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Ma J, Luu B, Ruderman SA, Whitney BM, Merrill JO, Mixson LS, Nance RM, Drumright LN, Hahn AW, Fredericksen RJ, Chander G, Lau B, McCaul ME, Safren S, O'Cleirigh C, Cropsey K, Mayer KH, Mathews WC, Moore RD, Napravnik S, Christopoulos K, Willig A, Jacobson JM, Webel A, Burkholder G, Mugavero MJ, Saag MS, Kitahata MM, Crane HM, Delaney JAC. Alcohol and drug use severity are independently associated with antiretroviral adherence in the current treatment era. AIDS Care 2024; 36:618-630. [PMID: 37419138 PMCID: PMC10771542 DOI: 10.1080/09540121.2023.2223899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 06/05/2023] [Indexed: 07/09/2023]
Abstract
Substance use in people with HIV (PWH) negatively impacts antiretroviral therapy (ART) adherence. However, less is known about this in the current treatment era and the impact of specific substances or severity of substance use. We examined the associations of alcohol, marijuana, and illicit drug use (methamphetamine/crystal, cocaine/crack, illicit opioids/heroin) and their severity of use with adherence using multivariable linear regression in adult PWH in care between 2016 and 2020 at 8 sites across the US. PWH completed assessments of alcohol use severity (AUDIT-C), drug use severity (modified ASSIST), and ART adherence (visual analogue scale). Among 9400 PWH, 16% reported current hazardous alcohol use, 31% current marijuana use, and 15% current use of ≥1 illicit drugs. In multivariable analysis, current methamphetamine/crystal use, particularly common among men who had sex with men, was associated with 10.1% lower mean ART adherence (p < 0.001) and 2.6% lower adherence per 5-point higher severity of use (ASSIST score) (p < 0.001). Current and more severe use of alcohol, marijuana, and other illicit drugs were also associated with lower adherence in a dose-dependent manner. In the current HIV treatment era, individualized substance use treatment, especially for methamphetamine/crystal, and ART adherence should be prioritized.
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Affiliation(s)
- J Ma
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - B Luu
- Department of Medicine, University of Toronto, Toronto, Canada
| | - S A Ruderman
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - B M Whitney
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - J O Merrill
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - L S Mixson
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - R M Nance
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - L N Drumright
- Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Biobehavioral Nursing and Health Informatics, University of Washington, Seattle, WA, USA
| | - A W Hahn
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - R J Fredericksen
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - G Chander
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - B Lau
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA
| | - M E McCaul
- Department of Psychiatry, Johns Hopkins University, Baltimore, MD, USA
| | - S Safren
- Department of Psychology, University of Miami, Miami, FL, USA
| | - C O'Cleirigh
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA
- Department of Psychology, Harvard Medical School, Boston, MA, USA
| | - K Cropsey
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - K H Mayer
- Department of Medicine, Harvard Medical School, Boston, MA, USA
- The Fenway Institute, Boston, MA, USA
| | - W C Mathews
- Department of Medicine, University of California, San Diego, CA, USA
| | - R D Moore
- Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - S Napravnik
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA
| | - K Christopoulos
- Department of Medicine, University of California, San Francisco, CA, USA
| | - A Willig
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - J M Jacobson
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - A Webel
- Department of Child, Family, and Population Health Nursing, Unviersity of Washington, Seattle, WA, USA
| | - G Burkholder
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - M J Mugavero
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - M S Saag
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - M M Kitahata
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - H M Crane
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - J A C Delaney
- Department of Medicine, University of Washington, Seattle, WA, USA
- College of Pharmacy, University of Manitoba, Winnipeg, Canada
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Tomlinson JL, Hahn AW, Constantinescu GM, Wagner-Mann C, Williams N. Heat Conduction of Fixator Pins with Polymethylmethacrylate External Fixation. Vet Comp Orthop Traumatol 2018. [DOI: 10.1055/s-0038-1632587] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
SummaryThe purpose of this study was to determine the degree of thermal conduction along the fixation pins associated with acrylic external fixators and to develop a means of minimizing the potential for thermal injury. The data suggest that the degree of temperature conducted with 1.9 cm diameter acrylic external fixators was of minimal clinical significance if maintained a distance of one centimeter from the patient’s tissues. Larger diameter columns increase the potential for injury, however, this can be minimized with the use of a constant saline drip at the pin-acrylic interface to facilitate heat loss.This article describes the evaluation of thermal properties of polymethylmethacrylate external skeletal fixators. The data demonstrate heat conduction along the fixation pins. Thermal injury is theoretically minimized if columns are maintained a distance of at least one centimeter from the patient’s tissue.Research supported in part by and presented for the University of Missouri Pi Chapter of the Honor Society of Phi Zeta in coordination with SmithKline Beecham Animal Health, April 7, 1994
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Hahn AW, Nussenzveig RH, Pal SK, Agarwal N. Blood- and tissue-based tumor genomics: a battle royale or match made in heaven? Ann Oncol 2018; 28:2333-2335. [PMID: 28945831 DOI: 10.1093/annonc/mdx418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- A W Hahn
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, USA
| | - R H Nussenzveig
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, USA
| | - S K Pal
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, USA
| | - N Agarwal
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, USA.
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4
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Henry CJ, Hahn AW, Tyler JW, Steinberg HS, Caldwell CW. Comparative Oncology Solution to Understanding Hormonal Impact in the Epidemiology of Lymphoma. Vet Comp Oncol 2005. [DOI: 10.1111/j.1476-5810.2005.0064c.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Folk LC, Hahn AW, Patrick TB, Allen GK, Smith AB, Wilcke JR. Salvaging legacy data: mapping an obsolete medical nomenclature to a modern one. Biomed Sci Instrum 2002; 38:405-10. [PMID: 12085640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The Veterinary Medical Database (VMDB) is a repository containing abstracts of over six million case records from 24 veterinary colleges throughout the U.S. and Canada. These case record abstracts, spanning almost 40 years, represent a valuable resource for outcomes analysis and hypothesis generation. Database records are currently encoded using the Standard Nomenclature of Veterinary Diseases and Operations (SNVDO), a precoordinated, hierarchical coding system. SNVDO has not been updated since 1977 and is outdated and inadequate to express the current state of medical knowledge. We undertook to manually map a subset of the SNVDO codes to a modern medical nomenclature, SNOMED-RT (Version 1.0), and to evaluate the quality of the resultant mappings and the acceptability of the mapping method used. We found that the distribution of frequency of use of the SNVDO codes in the VMDB records is highly skewed, with a small number of codes accounting for a large percentage of the records. We targeted our mapping efforts on that subset of codes. We found that our targeted manual mapping of the SNVDO codes to SNOMED-RT codes was feasible and produced good quality results, based on separate evaluations performed by two domain experts. However, a significant proportion of the SNVDO codes could not be mapped to a single SNOMED-RT concept, necessitating construction of multiple-code post-coordinated terms. Additionally, this manual mapping was very labor-intensive.
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Affiliation(s)
- L C Folk
- College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
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Fischer JW, Stoll M, Hahn AW, Unger T. Differential regulation of thrombospondin-1 and fibronectin by angiotensin II receptor subtypes in cultured endothelial cells. Cardiovasc Res 2001; 51:784-91. [PMID: 11530112 DOI: 10.1016/s0008-6363(01)00345-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVES Angiotensin II (ANG II) can modulate cellular proliferation in various cell types via AT(1) and AT(2) receptors. In the present study, we investigated the effect of the angiotensin AT(1) and AT(2) receptors on DNA-synthesis as well as on the expression of the extracellular matrix (ECM) components, thrombospondin-1 (TSP-1) and fibronectin (FN) in endothelial cells (EC). METHODS The experiments were performed in microvascular EC derived from rat heart (CEC) and macrovascular EC derived from bovine aorta (BAEC). The experiments were performed in cells of the second and third passage and the expression of AT(1) and AT(2) receptors was verified by binding studies, Northern analysis or RT-PCR. Quiescent rat CEC and BAEC were stimulated to proliferate by the addition of 25 ng/ml bFGF, while ANG II (10(-7) M) and the selective ANG II receptor antagonists, Losartan (10(-5) M) and PD123177 (10(-6) M) or the AT(2) agonist, CGP42112A (10(-7) M) were added 16 h later. RESULTS ANG II induced a dose-dependent decrease of DNA-synthesis in BAEC measured by [3H]-thymidine incorporation. This inhibitory effect of ANG II was prevented by the addition of the AT(2) receptor antagonist PD123177 (10(-6) M), demonstrating, that the inhibition of DNA synthesis is mediated by the AT(2) receptor. In the presence of Losartan, stimulation of both, CEC and BAEC, with ANG II resulted in a marked increase of TSP-1 mRNA levels, which was maximal between 3 and 6 h in rat CEC and after 9 h in BAEC. In addition, TSP-1 was clearly induced by the AT(2) agonist CGP42112A. In contrast, blockade of the AT(2) receptor by the selective AT(2) antagonist, PD123177 (10(-6) M), resulted in a pronounced down regulation of FN mRNA 9 h after the stimulation. CONCLUSIONS The present results suggest that the ANG II receptor subtype AT(2) mediates growth inhibition in macrovascular EC similar to what has been shown before in microvascular rat EC and that AT(2) receptors mediates remodeling of the endothelial ECM by upregulation of TSP-1 expression in both macro- and micro-vascular endothelial cells.
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Affiliation(s)
- J W Fischer
- Institute of Pharmacology, Christian-Albrechts-University Kiel, 24105 Kiel, Germany.
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7
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Thayer JF, Hahn AW, Pearson MA, Sollers JJ, Johnson PJ, Loch WE. Heart rate variability during exercise in the horse. Biomed Sci Instrum 2001; 34:246-51. [PMID: 9603047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
High heart rate variability (HRV) has been associated with more efficient autonomic control, allowing more responsivity and sensitivity to changing environmental demands. Previous results from spectral analysis of interbeat intervals of equine heart rate (HR) indicated increased HRV, reflecting more effective vagal control of the heart. This study focuses on characterizing equine HR and HRV during increasing then decreasing physical demand. A non-invasive ambulatory monitoring system continuously records HR and HRV as horses exercise on a high speed equine treadmill at increasing then decreasing workloads. After a 5 minute baseline, the horses walk, then trot, then canter or trot fast, return to the slower trot, then walk, and then remain quiet for a 5 minute recovery period. Results indicate a decrease of HRV and large individual differences in parasympathetic activity during exercise. Resulting patterns of HR fluctuation indicate a nonlinear dynamical approach may describe the task responses more completely than the more traditional models.
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Affiliation(s)
- J F Thayer
- Department of Psychology, University of Missouri-Columbia 65211, USA
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8
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Roth AC, Leon MA, Milner SM, Herting RL, Hahn AW. A personal digital assistant for determination of fluid needs for burn patients. Biomed Sci Instrum 2001; 34:186-90. [PMID: 9603036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In most instances, the treatment of major burn victims begins in the emergency room of the hospital closest to the accident site. It can be assumed that the emergency room personnel in most hospitals rarely see patients with major burns. Thus, their experience with burn fluid resuscitation is often limited. Yet it is critical that primary early treatment of burn injury with fluid resuscitation begin before the patient is admitted locally or transferred to a burn unit. To assist these individuals a fluid resuscitation calculation application has been developed to run on a hand-held personal digital assistant (Palm Pilot). This hand-held application is meant to assist in emergency situations where time is short, thoughtful computation is not possible, and a quick determination of fluid replacement therapy is important for the survival of the patient.
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Affiliation(s)
- A C Roth
- Department of Health Management and Informatics, University of Missouri-Columbia 65211, USA
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9
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Harada E, Yonezawa Y, Caldwell WM, Hahn AW. A microcontroller-based telemetry system for sympathetic nerve activity and ECG measurement. Biomed Sci Instrum 2001; 35:63-7. [PMID: 11143393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
A telemetry system employing a low power 8-bit microcontroller has been developed for chronic unanesthetized small animal studies. The two-channel system is designed for use with animals in shielded cages. Analog signals from implantable ECG and nerve electrodes are converted to an 8-bit serial digital format. This is accomplished by individual 8 bit A/D converters included in the microcontroller, which also has serial I/O port. The converted serial binary code is applied directly to an antenna wire. Therefore, the system does not need to employ a separate transmitter, such as in FM or infrared optical telemeters. The system is used in a shielded animal cage to reduce interference from external radio signals and 60 Hz power line fields. The code is received by a high input impedance amplifier in the cage and is then demodulated. The telemeter is powered by a small 3 V lithium battery, which provides 100 hours of continuous operation. The circuit is constructed on two 25 x 25 mm. printed circuit boards and encapsulated in epoxy, yielding a total volume of 6.25 cc. The weight is 15 g.
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Affiliation(s)
- E Harada
- Dept. of Electronics Engineering, Hiroshima Institute of Technology, Hiroshima 731-51, Japan
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10
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Hammann HP, Hahn AW. Acquisition, storage, and transmission of multi-species electrocardiographic data. Biomed Sci Instrum 2001; 35:199-204. [PMID: 11143347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
We have developed a system for a remotely accessible secure entry and storage of electrocardiographic (ECG) and associated data. It allows entry of data as a scanned TIFF file from any authorized remote user and is specifically designed to accommodate ECGs of multiple species. The system runs on a dual processor Pentium-II with FreeBSD 3.0 as the operating system. The database used is MySQL 3.22 with interface routines written in C and Perl 5.005. The Web server used is Apache 1.3.4. No client is needed other than an Internet connected computer with a Web browser such as Netscape Communicator or Microsoft Internet Explorer.
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Affiliation(s)
- H P Hammann
- Departments of Computer Engineering/Computer Science, Veterinary Medicine and Surgery and Health Management and Informatics, University of Missouri, Columbia, MO 65211, USA
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11
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Ohga Y, Yonezawa Y, Takamitsu M, Hahn AW, Caldwell WM. Spectral analysis of human tremor during cognitive tasks. Biomed Sci Instrum 2001; 37:101-3. [PMID: 11347370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Many stresses occur in our daily lives. Some of these are part of diseases of the nervous system such as ataxia and neuroses. Certain body tremors may be related to these stresses. The rhythmic movement of various muscle groups, similar to a fast circadian rhythm, is defined as a tremor. These tremors, occurring during cognitive tasks, have been recorded by one-dimensional accelerometer in use in our laboratory. In this expanded study, we recorded three-dimensional body displacements with an optical motion capture system while subjects were performing the tasks of intent listening, reading and mental arithmetic calculations. The recorded displacements were subjected to spectral analysis using the Fast Fourier transform (FFT). The results indicate that the body vibration amplitude spectrum caused by mental arithmetic is significantly increased in the frequency rage of 0.5 to 0.7 Hz, when compared to those recorded during other tasks. The induced tremor, as well as general invisible body micro-vibration, were obtained from the three-dimensional body displacements.
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Affiliation(s)
- Y Ohga
- Department of Electronics, Hiroshima Institute of Technology, Hiroshima 731-5193, Japan
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12
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Hahn AW. On stethoscope design: a challenge for biomedical circuit designers. Biomed Sci Instrum 2001; 37:499-503. [PMID: 11347442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Most clinicians learned the art and science of auscultation using an acoustic stethoscope. While many models of electronic stethoscopes have been marketed over the years, none of them seem to do a very good job of emulating the most common forms of acoustic stethoscopes available. This paper is an appeal to biomedical circuit designers to learn more about the acoustics of commonly used stethoscopes and to develop an appropriate group of circuits which would emulate them much like music synthesizers can emulate almost any musical instrument. The implications are for creative designers to move toward a rational and acceptable design for both personal physician use and for telemedicine.
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Affiliation(s)
- A W Hahn
- Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211, USA.
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13
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Ogawa H, Yonezawa Y, Maki H, Hahn AW, Caldwell WM. A Web-based home helper support system. Biomed Sci Instrum 2001; 37:95-9. [PMID: 11347452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
A web-based "Home Helper" support system has been developed for improving scheduling and record keeping efficiency and for eliminating unnecessary travel. This support system consists of a wireless internet mobile phone for each "Home Helper" and a server at the main office. After each visit, the Home Helpers send their care reports via the mobile phone to the office server. This server computer then creates the "filings" automatically and in appropriate format for insurance and government use.
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Affiliation(s)
- H Ogawa
- Department of Information, Hiroshima Institute of Technology Polytechnic, Hiroshima 733-8533, Japan
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14
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Uokawa Y, Yonezawa Y, Caldwell WM, Hahn AW. A microcomputer-based data acquisition system for ECG, body and ambient temperatures measurement during bathing. Biomed Sci Instrum 2000; 36:373-7. [PMID: 10834261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
A data acquisition system employing a low power 8 bit microcomputer has been developed for heart rate variability monitoring before, during and after bathing. The system consists of three integral chest electrodes, two temperature sensors, an instrumentation amplifier, a low power 8-bit single chip microcomputer (SMC) and a 4 MB compact flash memory (CFM). The ECG from the electrodes is converted to an 8-bit digital format at a 1 ms rate by an A/D converter in the SMC. Both signals from the body and ambient temperature sensors are converted to an 8-bit digital format every 1 second. These data are stored by the CFM. The system is powered by a rechargeable 3.6 V lithium battery. The 4 x 11 x 1 cm system is encapsulated in epoxy and silicone, yielding a total volume of 44 cc. The weight is 100 g.
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Affiliation(s)
- Y Uokawa
- Dept. of Electronics Engineering, Hiroshima Institute of Technology, Japan
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15
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Hahn AW, Folk LC, Patrick T, Smith AB, Hesse S, Allen GK. Developing a controlled vocabulary for use in a hospital information system. Biomed Sci Instrum 2000; 36:69-73. [PMID: 10834211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
In bringing a controlled vocabulary to a health information system, it is important to include those terms commonly used by those who must routinely input data to the system. We have developed a methodology whereby we can obtain "free text" descriptions of diagnoses entered by system users. We then sort those terms/concepts by system and find the appropriate "atomic" term(s). The terms are also being submitted to domain experts for appropriateness and fidelity. These concepts are then coded in an international coding system (SNOMED International) to eventually be entered into the controlled "pick list" of terms available for users to enter.
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Affiliation(s)
- A W Hahn
- Veterinary Medical Teaching Hospital, College of Veterinary Medicine, Columbia, MO, USA.
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16
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Smith AB, Hahn AW. Data model development as a prelude to implementing a hospital information system. Biomed Sci Instrum 1998; 33:263-8. [PMID: 9731369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We developed a data model for use in a veterinary teaching hospital using modern object oriented database diagramming. Since we deal with more than one species and often with herds or flocks, the problem became even more complex than the situation in human medicine. We chose to follow, insofar as possible, standards set forth by the HL7 consortium and the American Society for Testing and Materials (ASTM), two organizations deeply involved in setting standards for the health care record. Some modifications became necessary in order to fit the veterinary medical record to these standards but these were straightforward and did not disrupt the overall model. As a first step in constructing a hospital information system we have developed, and present herein, a data model which adequately addresses our needs in both the clinical and financial arenas and which conforms to appropriate standards as completely as possible.
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Affiliation(s)
- A B Smith
- Department of Veterinary Medicine and Surgery, Veterinary Medical Teaching Hospital, University of Missouri, Columbia 65211, USA.
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17
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Hammann HP, Suedmeyer WK, Hahn AW. A World Wide Web accessible multi-species ECG database. Biomed Sci Instrum 1998; 33:7-12. [PMID: 9731327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We have developed a system for remotely accessible secure electronic storage of electrocardiographic (ECG) and other associated data. It allows entry of data from any authorized remote user and is specifically built to accommodate the ECGs of multiple species. The present system is implemented on a Sun Sparc Solaris 2.5 platform using Oracle 7.3.2, and the Oracle 7.3.2 Web server. It may be easily ported to any other UNIX or Windows NT platform. No client is needed other than an Internet Protocol connected computer using a web browser such as Netscape Navigator or Microsoft Internet Explorer.
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Affiliation(s)
- H P Hammann
- Department of Computer Engineering, Veterinary Medical Hospital, Columbia, MO, USA
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18
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Hahn AW, Leon MA, Klein-Leon S, Allen GK, Boon GD, Patrick TB, Klimczak JC. Delivery of laboratory data with World Wide Web technology. Biomed Sci Instrum 1998; 33:252-6. [PMID: 9731367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We have developed an experimental World Wide Web (WWW) based system to deliver laboratory results to clinicians in our Veterinary Medical Teaching Hospital. Laboratory results are generated by the clinical pathology section of our Veterinary Medical Diagnostic Laboratory and stored in a legacy information system. This system does not interface directly to the hospital information system, and it cannot be accessed directly by clinicians. Our "meta" system first parses routine print reports and then instantiates the data into a modern, open-architecture relational database using a data model constructed with currently accepted international standards for data representation and communication. The system does not affect either of the existing legacy systems. Location-independent delivery of patient data is via a secure WWW based system which maximizes usability and allows "value-added" graphic representations. The data can be viewed with any web browser. Future extensibility and intra- and inter-institutional compatibility served as key design criteria. The system is in the process of being evaluated using accepted methods of assessment of information technologies.
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Affiliation(s)
- A W Hahn
- Department of Veterinary Medicine, University of Missouri, Columbia 65211, USA
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19
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May C, Hubing N, Hahn AW. Wavelet transforms for electrocardiogram processing. Biomed Sci Instrum 1998; 33:1-6. [PMID: 9731326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Wavelet transforms were used to remove noise and detect characteristic points for feline and human electrocardiograms. The electrocardiograms contained both 60 Hz line noise and wideband noise. Noise was removed from the signals using both Fourier and wavelet techniques. For the Fourier technique, the signals were notch filtered at 60 Hz, and then low-pass filtered. To remove noise using wavelet techniques, the signals were wavelet-transformed and then soft thresholding was performed on each of the resulting details. The two methods of removing noise were then compared to illustrate the advantages of the wavelet approach. Wavelet transforms were also used to detect a characteristic point on each beat. An algorithm was written to find this point, calculate the instantaneous heart rate, and then plot heart rate variability.
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Affiliation(s)
- C May
- Department of Electrical Engineering, University of Missouri, Rolla 65409-0040, USA
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Thayer JF, Hahn AW, Sollers JJ, van Doornen L, Johnson PJ. Heart rate variability in the horse by ambulatory monitoring. Biomed Sci Instrum 1998; 33:482-5. [PMID: 9731407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Using a microprocessor controlled Ambulatory Monitoring System (AMS) developed by one of us (LvD), we have been studying the changes in and control of heart rate in the resting horse. The system provides us with InterBeat Intervals (IBI in milliseconds), motion sensing, and a time domain measure (mean successive differences: MSD) of heart rate variability for periods up to 72 hours. Thoracic impedance is also available but parameters for the equine chest are not currently available. The system is completely noninvasive, small, and carried on a surcingle worn by the subject. The equine subject is confined to a stall in our teaching hospital but not otherwise restrained. Recording is virtually unobtrusive. Ten horses (judged to be clinically normal) were used in this preliminary study. After collection, the data were "offloaded" to a laptop computer for additional analysis. The electrocardiogram could be recorded on each of the ten animals. Complete data, suitable for spectral analysis, were obtained from four of the animals. Spectral estimates were calculated on periods of varying lengths (3-5 minutes) with more stable spectral estimates associated with longer recording periods. Results indicated the preponderance of parasympathetic control in equid heart rate. These results provide support for the utility of this method for the study of heart rate variability in the freely behaving horse.
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Affiliation(s)
- J F Thayer
- Department of Psychology, University of Missouri, Columbia 65211, USA
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21
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Smith AB, Hahn AW. Bringing a WEB-based interface to a hospital information system. Biomed Sci Instrum 1998; 34:303-8. [PMID: 9603057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Hospital Information System at the MU Veterinary Medical Teaching Hospital is a "home-grown" system written in MUMPS. The system has a "roll-and-scroll" user interface typical of terminal based systems from the 1970s and early 1980s. We are now introducing a new user interface that uses World Wide Web technology (HTML forms). Computers connected to the hospital's intranet can access the hospital system using the Web browser of the user's choice. The new user interface can run in parallel with the older interface (even on the same computer), and uses the same underlying database. This allows a smooth migration to the new interface which minimizes both user and programmer anguish. User acceptance has been good, and the ease and speed of development has been very promising.
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Affiliation(s)
- A B Smith
- Department of Veterinary Medicine and Surgery, Veterinary Medical Teaching Hospital, Columbia, MO, USA.
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22
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Smith AB, Hahn AW. Special considerations for WEB-based clinical database applications. Biomed Sci Instrum 1998; 34:297-302. [PMID: 9603056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Hospital Information System at the University of Missouri-Columbia Veterinary Medical Teaching Hospital is implementing a web-based interface to the existing Hospital Information System. The "stateless" nature of HTML forms introduces a number of special considerations that, though not immediately obvious, nevertheless apply to any multi-user database application. Problems including identifying sessions and users, dealing with abandoned sessions or use of the "Back" arrow on the browser, record locking across multiple forms, state variables, and flow through "utility" forms. General solutions to each of these problems have been devised and are presented here.
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Affiliation(s)
- A B Smith
- Department of Veterinary Medicine and Surgery, Veterinary Medical Teaching Hospital, Columbia, MO, USA.
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23
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Thommen R, Humar R, Misevic G, Pepper MS, Hahn AW, John M, Battegay EJ. PDGF-BB increases endothelial migration on cord movements during angiogenesis in vitro. J Cell Biochem 1997; 64:403-13. [PMID: 9057098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To explore direct effects of platelet-derived growth factor (PDGF) on endothelial cells during angiogenesis in vitro, we have used cloned bovine aortic endothelial cells that spontaneously form cord structures. Recently we have shown that cells forming these endothelial cords express PDGF beta-receptors and that PDGF-BB can contribute to cellular proliferation and cord formation. In this study we investigated whether PDGF-induced cellular migration might also contribute to endothelial repair and angiogenesis in vitro. Ten individual endothelial cells in cords were tracked at an early stage of cord formation by video-timelapse microscopy. PDGF-BB (100 ng/ml) induced an increase in endothelial cell movement of 67 +/- 15% as compared with diluent control. Interestingly, PDGF-BB also increased movements of entire cord structures, followed at branching points, by 53 +/- 12% over diluent control. Taken together, these video-timelapse experiments suggested that the apparent movements of single endothelial cord cells might also be due to the motion of entire underlying cord structures in response to PDGF. To analyze the response of single endothelial cord cells we therefore examined whether PDGF-induced migration contributes to endothelial repair. Abrasions were applied with a razor blade to confluent monolayers of endothelial cells at an intermediate stage of cord formation. PDGF-BB concentration-dependently increased the distance to which cord-forming endothelial cells migrated into the abrasion. An increased number of elongated, i.e., probably migrating, endothelial cells was found in the abrasion in response to PDGF-BB. However, there was no effect of PDGF-BB on the total number of endothelial cells found in the abrasion. PDGF-AA affected neither the distance to which the cells migrated nor the number of elongated cells. Actin and tubulin stainings revealed that these cytoskeletal structures were not appreciably altered by PDGF-BB. Furthermore, urokinase-type plasminogen activator transcripts were not modulated in response to PDGF-BB. We conclude that in this model of angiogenesis in vitro PDGF-BB can elicit the movement of entire cord structures, possibly via u-PA-independent mechanisms. PDGF-BB also controls the migration of single cord-forming endothelial cells. Thus, PDGF-BB possibly contributes to endothelial repair and angiogenesis by direct effects on proliferation and composite movements of PDGF beta-receptor-expressing endothelial cells and cords.
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Affiliation(s)
- R Thommen
- Department of Research, University Hospitals, Basel, Switzerland
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24
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Cavalot F, Russo I, Mattiello L, Anfossi G, Massucco P, Mularoni E, Hahn AW, Trovati M. Influence of protamine on adhesion, chemotaxis and proliferation of human vascular smooth muscle cells. Diabetologia 1997; 40:67-75. [PMID: 9028720 DOI: 10.1007/s001250050644] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
It has been shown that, in streptozotocin diabetic rats, protamine-retarded insulin administered in vivo stimulates intimal hyperplasia in balloon-injured carotid artery. The aim of this study was to evaluate the influence of protamine on cultured human vascular smooth muscle cells (h VSMC), by observing its effects on adhesion, chemotaxis and proliferation. hVSMC were isolated during abdominal surgery, cultured and utilized at passages 6-10. We observed that protamine stimulates: 1) cell adhesion in the concentration range 0.04-20 micrograms/ml (analysis of variance, ANOVA, p < 0.0001); 2) cell chemotaxis in the absence of fetal calf serum (FCS) in the concentration range 1-200 micrograms/ml (ANOVA, p < 0.0001) and in the presence of 1% FCS in the concentration range 5-200 micrograms/ml (ANOVA, p < 0.0001), further enhancing the chemotaxis induced by 10% FCS in the concentration range 20-200 micrograms/ml (ANOVA, p < 0.0001); 3) cell proliferation and 3H-thymidine incorporation from 1 to 5 micrograms/ml (ANOVA, p < 0.0001); 4) cell c-fos oncoprotein nuclear expression. We also observed that protamine effects on chemotaxis, proliferation and c-fos expression are inhibited by heparin that human insulin stimulates cell proliferation and 3H-thymidine incorporation (ANOVA, p < 0.0001) at concentrations equal to or greater than 480 pmol/l and that these effects of insulin persist in the presence of protamine. In conclusion, protamine influences hVSMC behaviour by interfering with biological functions involved in atherogenesis. The concentrations used in this short-term in vitro study were higher than those probably occurring in vivo in patients chronically treated by protamine-retarded insulin preparations: further studies, therefore, are needed to evaluate the safety of protamine as a retardant of insulin action in vivo.
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Affiliation(s)
- F Cavalot
- Department of Clinical and Biological Sciences, University of Turin, Italy
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Trovati M, Massucco P, Mattiello L, Cavalot F, Mularoni EM, Hahn AW, Anfossi G. Studies on the influence of insulin on cyclic adenosine monophosphate in human vascular smooth muscle cells: dependence on cyclic guanosine monophosphate and modulation of catecholamine effects. Diabetologia 1996; 39:1156-64. [PMID: 8897002 DOI: 10.1007/bf02658501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Insulin increases both cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) in human vascular smooth muscle cells (hVSMC) and attenuates noradrenaline-induced vasoconstriction. In the present study, we aimed at investigation in hVSMC: 1) the interrelationships between insulin-induced increases of cGMP and cAMP; 2) the insulin effect on the catecholamine modulation of cAMP. Catecholamines cause both vasoconstriction and vasodilation. Vasoconstriction is attributable to the reduced synthesis of cAMP in hVSMC through alpha 2-adrenoceptors and to direct effects on calcium fluxes through alpha 1-adrenoceptors; vasodilation is attributable to the increased synthesis of cAMP through beta-adrenoceptors. In the present study, we determined the influence of insulin on cAMP in hVSMC incubated with or without: a) the inhibitor of guanylate cyclase methylene blue or the inhibitor of nitric oxide synthase NG-monomethyl-L-arginine (L-NMMA); b) the beta-adrenergic agonists isoproterenol and salbutamol; c) the physiological catecholamines noradrenaline and adrenaline; d) noradrenaline+the beta-adrenergic antagonist propranolol or the alpha 2-adrenergic antagonist yohimbine; e) noradrenaline+methylene blue of L-NMMA. We demonstrated that: 1) the inhibition of the insulin-induced cGMP synthesis blunts the insulin-induced increase of cAMP; 2) insulin induces a significant increase of cAMP also in the presence of isoproterenol, salbutamol, noradrenaline and adrenaline: the combined effects of insulin and catecholamines were additive in some, but not in all the experiments; 3) insulin enhances the cAMP concentrations induced by noradrenaline also in the presence of alpha 2- or beta-adrenergic antagonists; 4) in the presence of methylene blue or L-NMMA insulin does not modify the noradrenaline effects on cAMP.
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Affiliation(s)
- M Trovati
- Department of Clinical and Biological Sciences, University of Turnin, San Luigi Gonzaga Hospital, Italy
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26
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Cavalot F, Anfossi G, Russo I, Mularoni E, Massucco P, Mattiello L, Burzacca S, Hahn AW, Trovati M. Nonenzymatic glycation of fibronectin impairs adhesive and proliferative properties of human vascular smooth muscle cells. Metabolism 1996; 45:285-92. [PMID: 8606633 DOI: 10.1016/s0026-0495(96)90280-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Nonenzymatic glycation of proteins is involved in the pathogenesis of diabetes vascular complications. Extracellular matrix proteins are a prominent target for nonenzymatic glycation because of their slow turnover rates. The aim of this study was to investigate the influence of human fibronectin (F) nonenzymatic glycation on adhesion and proliferation of cultured human vascular smooth muscle cells (hVSMC). Incubation of human F with 500 mmol/L D-glucose at 37 degrees C induced a time-dependent increase in fluorescence detectable at 440 nm after excitation at 363 nm. Nonenzymatic glycation did not affect binding of F itself to the plates. Adhesion of hVSMC to F increased with the increase of incubation time of the cells on the protein from 30 minutes up to 120 minutes and remained stable thereafter. Adhesion to glycated fibronectin (GF) was reduced in comparison to control F at all the different adhesion times. Adhesion of hVSMC to GF was reduced when F was exposed to glucose for 4, 9, or 28 days (P=.0417 to .0025), but not when F was exposed for 1 day. Adhesion of hVSMC to GF was reduced compared with adhesion to nonglycated F at all coating concentrations from 0.2 to 10 micrograms/mL (P=.05 to .014). Thus, nonenzymatic glycation of F impairs adhesion of hVSMC in vitro. Proliferation of hVSMC on F increased with increasing concentrations of the protein as coating agent (ANOVA:P<.0001 for both nonglycated F and GF). Proliferation with F glycated for 4, 9, and 28 days was reduced at concentrations of 1, 3, and 10 micrograms/mL as compared with proliferation with nonglycated F (P=.0253 to .0001). Proliferation on F glycated for only 1 day was not significantly reduced. When the number of hVSMC plated on control F was reduced by 25% to take into account the reduced adhesion, the number of cells that proliferated on F was still reduced. In conclusion, nonenzymatic glycation of F impairs adhesive and proliferative properties of hVSMC.
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Affiliation(s)
- F Cavalot
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Gonzaga Hospital-Orbassano, Italy
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27
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Rugh KS, Hahn AW. Effective written communication in biomedical sciences. Biomed Sci Instrum 1996; 32:285-291. [PMID: 8672681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The written word is the biomedical scientist's most important and most enduring communication tool. Nevertheless, the development of writing skills receives little attention in most scientific disciplines and the ability to conduct research is often viewed as more important than the ability to communicate the results of that research. Consequently, many scientists lack the writing skills necessary to effectively convey essential aspects of their research. In this paper, we will discuss the importance of good writing skills, give examples of common mistakes that are made in biomedical science writing and offer suggestions on how to improve written communication.
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Affiliation(s)
- K S Rugh
- WordsWorth Professional Communications, Rocheport, MO 65279, USA
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28
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Carson CA, Keller JM, McAdoo KK, Wang D, Higgins B, Bailey CW, Thorne JG, Payne BJ, Skala M, Hahn AW. Escherichia coli O157:H7 restriction pattern recognition by artificial neural network. J Clin Microbiol 1995; 33:2894-8. [PMID: 8576341 PMCID: PMC228602 DOI: 10.1128/jcm.33.11.2894-2898.1995] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
An artificial neural network model for the recognition of Escherichia coli O157:H7 restriction patterns was designed. In the training phase, images of two classes of E. coli isolates (O157:H7 and non-O157:H7) were digitized and transmitted to the neural network. The system was then tested for recognition of images not included in the training set. Promising results were achieved with the designed network configuration, providing a basis for further study. This application of a new generation of computation technology serves as an example of its usefulness in microbiology.
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Affiliation(s)
- C A Carson
- Department of Veterinary Microbiology, University of Missouri, Columbia 65211, USA
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29
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Schrope DP, Fox PR, Hahn AW, Bond B, Rosenthal S. Effects of electrocardiograph frequency filters on P-QRS-T amplitudes of the feline electrocardiogram. Am J Vet Res 1995; 56:1534-40. [PMID: 8585669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE--To determine whether standard manual frequency filters in the ON and OFF settings affected P-QRS-T voltages, discover whether recorded P-QRS-T voltages vary between commercial electrocardiographs, assess effects of frequency filters on base-line artifact, and evaluate ECG frequency content by high-fidelity recordings subjected to digital filters with variable frequencies. DESIGN--Sequential 10-lead ECG were recorded in 30 cats, using 3 commercial electrocardiographs to assess effects of manual frequency filters on the P-QRS-T wave forms. Three clinically normal cats were evaluated for ECG frequency content. ANIMALS--Thirty cats (13 with hypertrophic cardiomyopathy; 4 with restrictive cardiomyopathy; 3 hyperthyroid; 1 with ventricular septal defect; 1 with aortic stenosis; and 8 with no detectable cardiovascular disease). Three additional clinically normal cats were studied for effects of frequency filters on the ECG frequency content. PROCEDURES--Ten-lead ECG were recorded on each cat by use of 3 commercial electrocardiographs sequentially. For each machine, a recording was made with manual filters ON, immediately followed by a recording with manual filters OFF. High-fidelity lead-II ECG recordings were made with filters set with their rolloff frequency at 0.1 Hz and 3.0 kHz; output voltage (0.2 mV/V) was fed to an analog-to-digital converter, then to attendant software, which sampled the signal at 6 kHz with a 12-bit sampler, and were digitally filtered at various corner frequencies. RESULTS--Voltages recorded by all 3 electrocardiographs were greatest when filters were OFF (most prominent on R- and S-wave voltages). In all recorded leads, R-wave voltage was significantly greater when filters were OFF than ON. Comparison of voltages indicated significant (P < 0.05) differences between R-wave voltages recorded in all leads with manual filters ON, but not with filters OFF. With filters ON, each electrocardiograph produced a smaller percentage of recordings with moderate to severe baseline artifact than with filters OFF. R-Wave amplitudes of high-fidelity lead-II ECG were significantly decreased with digital filters set at corner frequencies < 150 Hz. CONCLUSIONS--Significant (P < 0.05) voltage attenuation was recorded by each of the 3 commercial electrocardiographs when frequency filters were ON, compared with OFF. Comparison of waveform voltages among electrocardiographs with filters ON indicated significant variation in R-wave amplitudes in all leads. With manual filters ON, each electrocardiograph recorded a smaller percentage of recordings with baseline artifact than with filters OFF. Substantial frequency components > or = 150 Hz are present in the feline ECG waveform. Thus, filters with frequencies < 150 Hz markedly attenuate the feline R wave. CLINICAL RELEVANCE--Attenuation of feline ECG signals occurs with use of commercial electrocardiographs and varies greatly between manufacturers. This is attributable largely to internal manual frequency filters. These consequences may be important when applying standard feline reference values or when equivocal voltage measurements are recorded.
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Affiliation(s)
- D P Schrope
- Department of Medicine, Animal Medical Center, New York, NY 10021, USA
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30
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Resink TJ, Bochkov VN, Hahn AW, Philippova MP, Bühler FR, Tkachuk VA. Low- and high-density lipoproteins as mitogenic factors for vascular smooth muscle cells: individual, additive and synergistic effects. J Vasc Res 1995; 32:328-38. [PMID: 7578801 DOI: 10.1159/000159107] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The mitogenic activities of low (LDL)- and high (HDL)-density lipoproteins have been examined in cultures of human vascular smooth muscle cells (VSMC). LDL and HDL3 dose-dependently (EC50 values approximately 50 micrograms/ml) stimulated DNA and protein synthesis ([3H]-thymidine and [3H]-leucine incorporation, respectively) in the absence of exogenously added mitogens. The synthetic responses of VSMC to combinations of LDL and HDL3 were additive, indicating that each lipoprotein mediates discrete effects. LDL or HDL3 promoted VSMC proliferation under strict mitogen-free conditions, but this growth response was not sustained. VSMC exposed to combinations of lipoproteins (either LDL or HDL3) and growth factors (either PDGF-BB, EGF, bFGF or IGF) exhibited synergistic DNA synthesis responses. In the combined presence of PDGF-BB and either LDL or HDL3, VSMC proliferation was sustained. Anionized lipoprotein preparations (oxidized, acetylated, carbamylated or malonimylated) also stimulated DNA and protein synthesis. Since the antioxidant beta-hydroxylated toluene did not block the effect of native LDL on DNA synthesis, and fucoidin, a specific competitor for the 'scavenger' receptor, did not inhibit oxidized LDL-induced DNA synthesis, activation of mitogenic signals by lipoproteins does not depend on lipid peroxidation. Rather, the apparent intrinsic mitogenic potential of lipoproteins may depend upon their direct activation of replication-coupled signal transduction systems.
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Affiliation(s)
- T J Resink
- Department of Research, University Hospital of Basel, Switzerland
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31
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Hahn AW, Schmidt R, Kern F, Resink TJ, Bühler FR. Endothelium-modulated proliferation of medial smooth muscle cells: influence of angiotensin II and converting enzyme inhibition. Eur Heart J 1995; 16 Suppl C:29-32. [PMID: 7556269 DOI: 10.1093/eurheartj/16.suppl_c.29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
This study investigated the role of the endothelium and angiotensin II (Ang II) in regulating medial smooth muscle cell (SMC) proliferation. [3H]-thymidine incorporation into medial SMC of rat arteries was examined in vivo, using ballooned rat carotid arteries, as well as in vitro, using cultures of aortic tissue rings (organoids). In vivo, maximal medial [3H]-thymidine incorporation occurred within 3 days post-ballooning. In endothelium-denuded organoids, maximum medial DNA synthesis was achieved after 7 days of culture. [3H]-thymidine-labelling of SMC in intact organoids (with endothelium) increased minimally during culture, indicating that the endothelium provided protection with respect to medial proliferation under basal conditions (culture in the presence of 1% plasma-derived serum). Inclusion of 10(-7) M Ang II significantly elevated medial [3H]-thymidine incorporation above that in control cultures. The stimulatory effect of Ang II was much more pronounced in intact organoids that in endothelium-denuded organoids, indicating synergistic growth regulation by Ang II and endothelium-derived factors. When organoids were cultured in the combined presence of Ang II and the ACE inhibitor cilazaprilat, labelling indices of intact organoids were also significantly increased above control, but to a lower level than those obtained in the presence of Ang II alone. However, for endothelium-denuded organoids, medial [3H]-thymidine incorporation in the combined presence of Ang II and cilazaprilat was not significantly different from that in untreated controls. Thus, cilazaprilat exerts both endothelium-dependent and endothelium-independent negative regulatory effects on medial SMC proliferation.
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Affiliation(s)
- A W Hahn
- Department of Research, University Clinics Basel, Switzerland
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32
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Abstract
The arterial tenascin C expression in vivo and in vitro has been studied using immunohistochemistry. The functional relevance of localized tenascin C expression was assessed in vitro using various human cell types involved in the progression of vascular disease. Normotensive and hypertensive rats exhibited age-dependent patterns of vascular (aorta) tenascin expression, but the lumen-to-media-directed progression of tenascin induction was accelerated in hypertensive rats. Tenascin-rich neointimal lesions (spontaneous) were observed at branching sites of aorta from aged (80 weeks) hypertensive rats. Subendothelial tenascin foci contained lipid-laden smooth muscle cells and monocytes/macrophages. Medial tenascin foci encaged smooth muscle cells which synthesized DNA. Tenascin was expressed both in vivo and in vitro by endothelial and smooth muscle cells but not by monocytes/macrophages; angiotensin II, oxidized-low density lipoprotein and transforming growth factor beta 1 induced expression of tenascin transcripts and glycoprotein in vitro. Endothelial and smooth muscle cells, but not monocytes, adhered to tenascin substrata. Tenascin reduced focal adhesion integrity in confluent endothelial and smooth muscle cell cultures. Angiotensin II-induced migration of endothelial and smooth muscle cells was accompanied by tenascin deposition within extracellular matrix migration trails. Tenascin may function both as a defense against monocyte invasion and medial smooth muscle replication, as well as a substratum for directed endothelial and smooth muscle cell migration.
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Affiliation(s)
- A W Hahn
- Department of Research, University Clinics Basel, Switzerland
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33
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Birukov KG, Shirinsky VP, Stepanova OV, Tkachuk VA, Hahn AW, Resink TJ, Smirnov VN. Stretch affects phenotype and proliferation of vascular smooth muscle cells. Mol Cell Biochem 1995; 144:131-9. [PMID: 7623784 DOI: 10.1007/bf00944392] [Citation(s) in RCA: 155] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The exertion of periodic dynamic strain on the arterial wall is hypothesized to be relevant to smooth muscle cell morphology and function. This study has investigated the effect of cyclic mechanical stretching on rabbit aortic smooth muscle cell proliferation and expression of contractile phenotype protein markers. Cells were cultured on flexible-bottomed dishes and cyclic stretch was applied (frequency 30 cycles/min, 15% elongation) using a Flexercell Strain unit. Cyclic stretch potentiated smooth muscle cell proliferation in serum-activated cultures but not in cultures maintained in 0.5% fetal calf serum. Stretching induced a serum-independent increase of h-caldesmon expression and this effect was reversible following termination of mechanical stimulation. Strain was without effect on smooth muscle myosin or calponin expression. In cells grown on laminin stretch-induced h-caldesmon expression was more prominent than in cells cultured on collagen types I and IV, poly-L-lysine and gelatin. These data suggest that cyclic mechanical stimulation possesses dual effect on vascular smooth muscle cell phenotype characteristics since it: 1) potentiates proliferation, an attribute of a dedifferentiated phenotype; and 2) increases expression of h-caldesmon considered a marker of a differentiated smooth muscle cell state.
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Affiliation(s)
- K G Birukov
- Laboratory of Molecular Endocrinology, Russian Academy of Medical Sciences, Moscow
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34
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Hausam RR, Hahn AW. Representation of clinical problem assessment phrases in U.S. family practice using Read version 3.1 terms: a preliminary study. Proc Annu Symp Comput Appl Med Care 1995:426-30. [PMID: 8563317 PMCID: PMC2579128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Read Codes from the United Kingdom are a comprehensive clinical vocabulary, and one of the most likely candidates for adoption as a standard for use in Computer-Based Patient Record (CPR) systems. The new version 3.1 codes represent a major enhancement to the content and structure of the coding system, including incorporation of a new hierarchy and an explicit model for the use of qualifier terms. This is a preliminary study investigating the suitability of these codes for representing clinical problem assessment phrases in U.S. family practice. Problem assessment phrases from outpatient progress notes were encoded into the equivalent Read terms. The problem assessment phrases were evaluated for complexity and clarity. The coded representations of the phrases were evaluated for clinical acceptability. A list of coding difficulties was compiled. The most common difficulties were (1) qualifier terms present but not allowable for that Read concept (24%), and (2) qualifier terms not present (20%). British spelling and abbreviation variants were noted, but were relatively insignificant. The Read codes appear to be suitable for use in U.S. primary care practice with fairly minor modifications, but further development is required to expand the content and structure of the model for qualifier terms.
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Affiliation(s)
- R R Hausam
- Medical Informatics Group, University of Missouri-Columbia, USA
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35
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Abstract
This study has investigated the ability of the vasoconstrictor peptide angiotensin II to activate human peripheral blood monocytes. Activation was monitored by measuring both the release of tumor necrosis factor alpha from monocytes and their adhesion to monolayers of human endothelial cells. Angiotensin II-elicited activation of monocytes was dose-dependent (half-maximally effective concentration approximately 0.2 nM), saturable (maximally effective concentration approximately 5 nM), and sensitive to inhibition by the angiotensin type 1 receptor antagonist ZD 7155. Such direct actions imply that angiotensin II is an important candidate stimulus for the subendothelial infiltration of monocytes observed in atherogenesis and hypertension.
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Affiliation(s)
- A W Hahn
- Department of Research, University Clinics Basel, Switzerland
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Crabos M, Roth M, Hahn AW, Erne P. Characterization of angiotensin II receptors in cultured adult rat cardiac fibroblasts. Coupling to signaling systems and gene expression. J Clin Invest 1994; 93:2372-8. [PMID: 8200970 PMCID: PMC294443 DOI: 10.1172/jci117243] [Citation(s) in RCA: 181] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cardiac hypertrophy is largely due to cardiac fibroblast growth and increased synthesis of extracellular matrix. This study has investigated the contribution of the vasoactive hormone, angiotensin II, toward this hypertrophic process. We have demonstrated that cultures of adult rat cardiac fibroblasts express AT1 but not AT2 receptors for angiotensin II. The ability of angiotensin II to stimulate phosphoinositide catabolism and to elevate intracellular calcium concentrations in these cells was blocked by losartan, a specific AT1 receptor antagonist, but not by the AT2 receptor antagonist CGP 42112. Exposure of adult cardiac fibroblasts to angiotensin II resulted in the induction of several growth-related metabolic events including c-fos protooncogene expression and increased synthesis of DNA, RNA, and protein. Angiotensin II was also found to induce collagen type I, alpha 1 chain transcript expression in cardiac fibroblasts as well as the synthesis and secretion of collagen by these cells. The data demonstrate that angiotensin II, via AT1 receptors, can stimulate cardiac fibroblast growth and increase collagen synthesis in cardiac tissue. Thus, angiotensin II may contribute toward the development of cardiac hypertrophy in conditions of hypertension that are associated with elevated concentrations of angiotensin II.
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Affiliation(s)
- M Crabos
- Department of Research, University Hospital, Basel, Switzerland
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37
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Regenass S, Resink TJ, Kern F, Bühler FR, Hahn AW. Angiotensin-II-induced expression of laminin complex and laminin A-chain-related transcripts in vascular smooth muscle cells. J Vasc Res 1994; 31:163-72. [PMID: 8148467 DOI: 10.1159/000159042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Laminin, a major structural glycoprotein complex of basement membranes has been found to be modulated by angiotensin II in vitro and in vivo. In cultures of aortic organoids and vascular smooth muscle cells, expression of laminin was stimulated by exogenous vasoconstrictor peptide. Stimulation of laminin protein and mRNA expression was observed for both laminin B1/B2-chains and an unknown laminin heavy chain. Compared with PYS-2 cells, a mouse teratocarcinoma cell line which constitutively expresses a 10-kb mRNA transcript for 'classical' laminin A-chain, cultured vascular smooth muscle cells (VSMC) did not express a corresponding mRNA. However, cultured VSMC were found to express laminin A-chain-related mRNAs of approximately 1.8 kb and approximately 3.8 kb, respectively. The 1.8-kb species of transcript was expressed in a constitutive manner, whereas the 3.8-kb mRNA was found to be regulated by angiotensin II. Laminin complexes secreted by cultured cells contained a approximately 300 kD heavy chain which did not immunoreact with immunoreagents raised against either the classical laminin complex secreted by EHS tumor cells or the merosin heavy chain. The putative A-chain analogue possibly represents a new form of a tissue-specific laminin heavy chain, distinct from the A- and M-chains thus far described. Translation products encoded by the A-chain-related transcripts of cultured smooth muscle cells could not be specified using currently available antibodies. The putative protein(s) is speculated to contain the biological features of the N-terminus of the laminin A-chain, namely self-assembly and association with collagen type IV.
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MESH Headings
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Blotting, Northern
- Blotting, Western
- Cells, Cultured
- DNA Probes
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Gene Expression Regulation
- Immunohistochemistry
- Laminin/biosynthesis
- Laminin/genetics
- Male
- Mice
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Organoids/drug effects
- Organoids/metabolism
- Precipitin Tests
- Protein Biosynthesis
- RNA, Messenger/biosynthesis
- Rats
- Rats, Inbred SHR
- Teratocarcinoma/metabolism
- Transcription, Genetic
- Tumor Cells, Cultured
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Affiliation(s)
- S Regenass
- Department of Research, Basel University Hospital, Switzerland
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38
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Klimczak JC, Hahn AW, Sievert M, Mitchell JA. Getting around in a large nomenclature file: browsing SNOMED international. Proc Annu Symp Comput Appl Med Care 1994:1023. [PMID: 7949860 PMCID: PMC2247848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- J C Klimczak
- Medical Informatics Group, University of Missouri, Columbia 65211
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39
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Hahn AW, Knowles MJ, Klimczak JC. A "listener/viewer" for phonocardiograms. Proc Annu Symp Comput Appl Med Care 1994:1039. [PMID: 7949877 PMCID: PMC2247977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A W Hahn
- Medical Informatics Group, University of Missouri, Columbia 65211
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40
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Resink TJ, Bochkov VN, Tkachuk VA, Bühler FR, Hahn AW. Lipoproteins and angiotensin II exert synergistic effects on signalling processes in vascular smooth muscle cells. J Hypertens Suppl 1993; 11:S110-1. [PMID: 8158299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
MESH Headings
- Angiotensin II/administration & dosage
- Angiotensin II/pharmacology
- Angiotensin II/physiology
- Cells, Cultured
- Drug Synergism
- Humans
- Inositol Phosphates/biosynthesis
- Lipoproteins, HDL/administration & dosage
- Lipoproteins, HDL/pharmacology
- Lipoproteins, HDL/physiology
- Lipoproteins, LDL/administration & dosage
- Lipoproteins, LDL/pharmacology
- Lipoproteins, LDL/physiology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Signal Transduction/drug effects
- Signal Transduction/physiology
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Affiliation(s)
- T J Resink
- Department of Research, Basel University Hospital, Switzerland
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41
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Anderson MA, Mann FA, Wagner-Mann C, Hahn AW, Jiang BL, Tomlinson JL. A comparison of nonthreaded, enhanced threaded, and Ellis fixation pins used in type I external skeletal fixators in dogs. Vet Surg 1993; 22:482-9. [PMID: 8116204 DOI: 10.1111/j.1532-950x.1993.tb00425.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Three different pin types (Ellis, enhanced threaded, and nonthreaded) were used in type 1 external skeletal fixation after transverse osteotomy of the radius and ulna in 12 skeletally mature dogs. Dogs were placed into three groups of four dogs based on the pin type used. Axial extraction forces were determined for each of the pin types after 8 weeks of weight bearing (chronic study). Nine contralateral radii were used to determine axial extraction forces for nine of each pin type not subjected to weight bearing forces (acute study). The force required for extraction of the enhanced threaded and Ellis pins in the chronic and acute studies was not significantly different. The force required to extract the nonthreaded pins was significantly less than that required for the other two pin types. Ground reaction forces had returned to levels measured before surgery by 2 weeks after surgery in the enhanced threaded and Ellis pin groups, however, dogs in the nonthreaded pin group required 4 weeks until normal ground reaction forces were measured. Radiographic evaluations 1, 2, 4, 6, and 8 weeks after surgery showed no difference among groups in the number of pin tract radiolucencies, however, the enhanced threaded pins had caused more trans-cortical chip fractures than the other two pin types. None of the pins broke during the eight-week chronic study.
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Affiliation(s)
- M A Anderson
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, School of Medicine, University of Missouri, Columbia
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42
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Hausam RR, Klimczak JC, Hahn AW. Computerized medical records--new opportunities. Mo Med 1993; 90:705-6. [PMID: 8277934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The new generation of computer hardware and software is providing many new opportunities for physicians to use computerized medical records in their practices. A substantial number of new commercial systems have been introduced within the past few years, and many more will likely become available soon. In addition, there are opportunities for physicians to create their own customized systems using new software tools now available.
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Bochkov VN, Tkachuk VA, Hahn AW, Bernhardt J, Buhler FR, Resink TJ. Concerted effects of lipoproteins and angiotensin II on signal transduction processes in vascular smooth muscle cells. Arterioscler Thromb 1993; 13:1261-9. [PMID: 8364010 DOI: 10.1161/01.atv.13.9.1261] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Low-density (LDL) and high-density (HDL3) lipoproteins dose-dependently activate phosphoinositide turnover and elevate cytosolic free Ca2+ concentrations ([Ca2+]i) in cultured vascular smooth muscle cells (VSMCs) from either human (microarterioles and aorta) or rat (aorta) sources. High-performance liquid chromatography analysis of cell extracts revealed comparable spectra of inositol phosphate isomers generated in response to either LDL, HDL3, or angiotensin II (Ang II). Thus, lipoproteins and Ang II may use similar, if not identical, signal transduction pathways for the generation and metabolism of inositol phosphates and intracellular Ca2+ mobilization in VSMCs. When Ang II was added in combination with either LDL or HDL3, the phosphoinositide and [Ca2+]i responses of VSMCs were either equal to or even greater than the sum of the effects elicited by the agonists individually. This additivity/synergy between Ang II and the lipoproteins was not accompanied by alteration in the half-maximally effective dose requirements of VSMCs for either Ang II (approximately 2 nmol/L, with or without lipoproteins) or lipoproteins (approximately 50 micrograms/mL for LDL and HDL3, with or without Ang II). Neither short-term (up to 10 minutes) nor long-term (48 hours) exposure of VSMCs to lipoproteins caused desensitization of phospholipase C and intracellular Ca2+ mobilization responses to either Ang II or lipoproteins. Since constant exposure of VSMCs to lipoproteins is a physiological circumstance, and because elevation of [Ca2+]i and activation of phosphoinositide turnover are pivotal events for VSMC contraction and growth, we suggest that the low concentrations of lipoproteins in the vessel intima may play an important role in regulating the response of the vasculature to Ang II.
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Affiliation(s)
- V N Bochkov
- Department of Research, Basel University Hospital, Switzerland
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44
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Abstract
Endothelin-1 (ET-1), a vasoconstrictor peptide produced by endothelial and vascular smooth muscle cells (VSMC) might play a role in vascular remodelling. To investigate the proposed 'mitogenic' potential of ET-1, we examined the effects of chronic exposure of VSMC to ET-1 on cell cycle, growth/proliferation and differentiation under essentially mitogen-free culture conditions. Bulk cultures of thoracic aortic VSMC of spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats, although exhibiting genetically determined differences in growth/proliferation (due to shortened G1 and G2 phases in SHR VSMC), respond in a similar manner to ET-1 exposure: long-term exposure (12-15 days) of VSMC from both sources to ET-1 in nonmitogenic medium did not promote cycling of cells. On the contrary, ET-1 attenuated the cycling of VSMC which had already cycled beyond the S phase. For cells which had not cycled beyond the S phase, ET-1 interrupted progression through the cell cycle at the late G1/early S phase. The specific ability of SHR VSMC to grow in mitogen-free medium was abolished by ET-1, most likely via down-regulation of platelet-derived growth factor (PDGF)-alpha receptors. Subsequent to ET-1 exposure, VSMC expressed increased levels of mRNA and protein for smooth-muscle-specific alpha-actin. However, expression of smooth muscle alpha-actin did not predominate over beta-actin as observed for adult contractile VSMC in vivo. The ET-1-induced expression of smooth-muscle-specific alpha-actin mRNA was dose dependent (EC50 approx. 2 x 10(-9) M), and alpha-actin protein expressed was associated with organized actin fibers.
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Affiliation(s)
- A W Hahn
- Department of Research, University Hospital, Basel, Switzerland
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45
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Abstract
Angiotensin II is a major regulator of cardiovascular function, fluid homeostasis and also plays a role in long-term cardiovascular disease processes. At present it is unclear if and how the diverse functions of angiotensin II may relate to different cellular receptors for this vasoactive peptide. In order to identify subtypes of angiotensin receptors we used a PCR-mediated cloning approach. Oligonucleotide sequences for PCR amplification of angiotensin receptors were selected on the basis of nucleotide sequences conserved between species. Since the coding regions of AT1-type receptors appear to be located on a single exon, we used genomic DNA as a template in the PCR reactions. Resulting amplification products represented a mixture of four different sequences as assessed by T-tracking and sequencing of the partial clones. Three of the clones encode for sequences already known, whereas the fourth clone encoded a novel receptor subtype which we have termed AT1C. Deduced amino acid sequences of the four different receptor subtypes are highly homologous. The AT1C receptor nucleotide sequence homology was greatest to the described AT3 receptor (95%) and less so to the published AT1A (90%) and AT1B (82%) receptor subtypes. The variety and tissue- specific expression of AT1 receptor subtypes and coexpression of different receptor subtypes may account for the diverse tissue- specific actions of angiotensin.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- DNA/genetics
- DNA/isolation & purification
- Female
- Glomerular Mesangium/metabolism
- Molecular Sequence Data
- Muscle, Smooth, Vascular/metabolism
- Oligodeoxyribonucleotides
- Oligonucleotides, Antisense
- Organ Specificity
- Placenta/metabolism
- Polymerase Chain Reaction
- Pregnancy
- RNA, Messenger/genetics
- RNA, Messenger/isolation & purification
- RNA, Messenger/metabolism
- Rats
- Receptors, Angiotensin/genetics
- Restriction Mapping
- Sequence Homology, Amino Acid
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Affiliation(s)
- A W Hahn
- Department of Research, Basel University Hospitals, Switzerland
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46
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Hahn AW, Resink TJ, Mackie E, Scott-Burden T, Bühler FR. Effects of peptide vasoconstrictors on vessel structure. Am J Med 1993; 94:13S-19S. [PMID: 8488851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The peptide vasoconstrictors angiotensin II and endothelin-1, originally described as being derived exclusively from the plasma renin-angiotensin system and vascular endothelium, respectively, have been demonstrated to be produced independently of these sources. Local tissue angiotensin-generating systems are well documented and endothelin production has been demonstrated for a variety of nonendothelial cells, including vascular smooth muscle cells. There is increasing evidence that these locally produced vasoconstrictor peptides may contribute to blood vessel homeostasis, as well as the development of vascular pathologic conditions. Results obtained from pharmaceutical intervention in humans and animals of these systems strongly support this hypothesis. In addition to their vasoconstrictor properties, angiotensin II and endothelin-1 act as potent biologic effectors. In vitro, both vasoconstrictor peptides appear to modulate the activity of autocrine feedback loops in vascular smooth muscle cells. The activity of these feedback loops in vivo may represent a central mechanism for regulation and phenotypic differentiation of this cell type. The most well-established autocrine feedback loops of vascular smooth muscle cells are constituted by platelet-derived growth factor and transforming growth factor-beta, both of which are influenced by the action of angiotensin II and endothelin-1. The effects of the peptide vasoconstrictors on the (auto-) regulated feedback loops are of long-term structural importance, since both vasoconstrictors (via autocrine growth modulators) may influence the composition of the extracellular matrix of vascular smooth muscle cells. This includes effects on the synthesis and secretion of thrombospondin, fibronectin, tenascin, etc. The secretion of extracellular matrix glycoproteins themselves and incorporation into extracellular matrix in vitro appear to be linked to the activity of the autocrine feedback loops: e.g., stimulation of thrombospondin mRNA results in secretion of the glycoprotein only in the concomitant presence of exogenous platelet-derived growth factor, whereas the expression of fibronectin and tenascin may be directed by transforming growth factor-beta. The influence of angiotensin II and endothelin-1 on vascular smooth muscle cell surface receptor expression may represent a secondary mode of action of these vasoconstrictor peptides. Endothelin-1, for instance, can rapidly down-regulate platelet-derived growth factor-alpha receptor mRNA and both angiotensin II and endothelin-1, via induction of transforming growth factor-beta, may interrupt the platelet-derived growth factor based autocrine feedback loop. In vivo, the highly complex interactions between local and systemic vasoconstrictor production, autoregulated feedback loops, and extracellular matrix (which also serves as a reservoir for growth and differentiation modulators) are central to vessel homeostasis.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- A W Hahn
- Department of Research, University Hospitals Basel, Switzerland
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47
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Hahn AW, Regenass S, Kern F, Bühler FR, Resink TJ. Expression of soluble and insoluble fibronectin in rat aorta: effects of angiotensin II and endothelin-1. Biochem Biophys Res Commun 1993; 192:189-97. [PMID: 8476421 DOI: 10.1006/bbrc.1993.1399] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study has investigated the influence of the vasoconstrictor peptides angiotensin II (Ang II) and endothelin-1 (ET-1) on fibronectin expression by vascular smooth muscle cells (VSMC). In confluent, quiescent cultures of VSMC, Ang II and ET-1 elevated fibronectin mRNA levels in a time- and dose-dependent fashion. ET-1 and Ang II also induced a time-dependent expression of immunoreactive fibronectin in cultures of aortic organoids, and for both peptides the fibronectin immunoreactivity was most prominent within those medial smooth muscle cell layers close to the vessel lumen. Immunoprecipitation of biosynthetically labelled fibronectin elaborated by cultured VSMC revealed a predominant expression of soluble fibronectin in response to Ang II, whereas for ET-1 the newly synthesized fibronectin was predominantly incorporated into the extracellular matrix deposit of the cells. These findings indicate that Ang II and ET-1 may exert disparate effects on smooth muscle cell phenotype and migration.
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Affiliation(s)
- A W Hahn
- Department of Research, Basel University Hospitals, Switzerland
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48
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Affiliation(s)
- T F Lüscher
- Department of Medicine, University Hospital Basel, Switzerland
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49
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Abstract
A hallmark of vascular disease is the inappropriate proliferative and synthetic behaviour of vascular smooth muscle cells. This phenotypically immature behaviour arises as a consequence of the myocytes undergoing phenotypic conversion and/or clonal proliferation of a "fetal" type of smooth muscle cell preexisting in the vessel wall. De-differentiation and initiation of proliferation is not only induced by endothelial desquamation and acute exposure of smooth muscle cells to platelet-derived mitogens, but also occurs in the uninjured blood vessel. Therefore normal components of the blood vessel are implicit in the pathological process. These include vasoconstrictor peptides, growth factor peptides and extracellular matrix molecules. In vitro and in vivo experimentation has indicated that while some of these compounds individually are only mild stimulators of smooth muscle proliferative metabolism, they may act synergistically to induce robust responses. Here we discuss the effects of the vasoconstrictor peptide angiotensin II, which can be locally generated within the vessel wall itself, on the expression of extracellular matrix molecules in vitro and in vivo. We focus on the angiotensin II-modulated expression of extracellular matrix glycoproteins, e.g. thrombospondin, tenascin, fibronectin and laminin.
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Affiliation(s)
- A W Hahn
- Departement Innere Medizin, Kantonsspital Basel
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50
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Affiliation(s)
- T F Lüscher
- Department of Medicine, University Hospital Basel, Switzerland
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