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Kollech HG, Chao MR, Stark AC, German RZ, Paniello RC, Christensen MB, Barkmeier-Kraemer JM, Vande Geest JP. Extracellular matrix deformations of the porcine recurrent laryngeal nerve in response to hydrostatic pressure. Acta Biomater 2022; 153:364-373. [PMID: 36152909 PMCID: PMC10627241 DOI: 10.1016/j.actbio.2022.09.039] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 08/22/2022] [Accepted: 09/15/2022] [Indexed: 11/25/2022]
Abstract
Damage to the recurrent laryngeal nerve (RLN) caused by supraphysiological compression or tension imposed by adjacent tissue structures, such as the aorta, may contribute to onset of idiopathic unilateral vocal fold paralysis (iUVP) resulting in difficulty speaking, breathing, and swallowing. We previously demonstrated in adolescent pigs that the right RLN epineurium exhibits uniform composition of adipose tissue, with larger quantities along its length within the neck region in contrast to the left RLN that shows greater collagen composition in the thoracic region and greater quantities of adipose tissue in the neck region. In contrast, the epineurium in piglets was primarily composed of collagen tissue that remained uniform along the length of the left and right RLNs. Tensile testing of the left and right RLN in piglets and pigs showed associated differences in strain by RLN side and segment by age. The goal of this study was to investigate how external hydrostatic compression of the RLN affects the nerve's connective tissue and microstructure. RLN segments were harvested from the distal (cervical/neck) regions and proximal (subclavian for the right RLN, thoracic for the left RLN) regions from eight adolescent pigs and nine piglets. RLN segments were isolated and assessed under fluid compression to test hypotheses regarding epineurium composition and response to applied forces. Second harmonic generation (SHG) imaging of epineurial collagen was conducted at 0, 40, and 80 mmHg of compression. The cartesian strain tensor, principal strain (Eps1), and principal direction of the RLN collagen fibers were determined at each pressure step. Significantly larger values of the 1st principal strain occurred in the proximal segments of the pig left RLN when compared to the same segment in piglets (p = 0.001, pig = 0.0287 [IQR = 0.0161 - 0.0428], piglet = 0.0061 [IQR = 0.0033 - 0.0156]). Additionally, the median transverse strain Eyy) for the second pressure increment was larger in the right proximal segment of pigs compared to piglets (p < 0.001, pig = 0.0122 [IQR = 0.0033 - 0.0171], piglet = 0.0013 [IQR = 0.00001 - 0.0028]). Eyy values were significantly larger in the right proximal RLN versus the left proximal RLNs in pigs but not in piglets (p < 0.001). In contrast to piglets, histological analysis of pig RLN demonstrated increased axial alignment of epineurial and endoneurial collagen in response to compressive pressure. These findings support the hypothesis that the biomechanical response of the RLN to compressive pressure changed from being similar to being different between the right and left RLNs during development in the porcine model. Further investigation of these findings associated with age-related onset of idiopathic UVP may illuminate underlying etiologic mechanisms. STATEMENT OF SIGNIFICANCE: Damage to the recurrent laryngeal nerve (RLN) caused by compression imposed by the aorta may contribute to the onset of left-sided idiopathic unilateral vocal fold paralysis resulting in difficulty speaking, breathing, and swallowing. The goal of this study was to investigate how compression affects the connective tissue and microstructure of the RLN. We quantified the pressure induced deformation of the RLN using multiphoton imaging as a function of both location (proximal versus distal) and age (piglets, adolescent pigs). Our results demonstrate that the biomechanical response of the RLN to compression changes in the right versus left RLN throughout development, providing further evidence that the the left RLN is exposed to increasing dynamic loads with age.
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Affiliation(s)
- Hirut G Kollech
- Computational Modeling and Simulation Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Melissa R Chao
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - Amanda C Stark
- National Center for Voice and Speech, University of Utah, Salt Lake City, UT, USA
| | - Rebecca Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA
| | - Randal C Paniello
- Department of Otolaryngology - Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Julie M Barkmeier-Kraemer
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Utah, UT, USA
| | - Jonathan P Vande Geest
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Mechanical Engineering and Material Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Allen-Brady KL, Christensen MB, Sandberg AD, Pastuszak AW. Significant familial clustering of Peyronie's disease in close and distant relatives. Andrology 2022; 10:1361-1367. [PMID: 35770847 PMCID: PMC9481671 DOI: 10.1111/andr.13223] [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: 02/17/2022] [Revised: 06/08/2022] [Accepted: 06/23/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND Peyronie's disease (PD) has previously been observed to co-aggregate in a small number of first-degree relative pairs (e.g., father-son). However, the familial aggregation of PD in more distant relatives, as well as the aggregation of Dupuytren's disease (DD) in probands and relatives, has not been thoroughly investigated. OBJECTIVE This study explored the evidence for familial clustering of PD and DD in close and distant relatives. MATERIALS AND METHODS The Utah Population Database, which includes genealogy information linked to electronic medical records (available since 1995), was used to identify men and their relatives with PD and DD based on ICD9/10 codes. All cases were required to have high-quality genealogy data. We estimated relative risk (RR) of PD and DD in first- through fifth-degree relatives compared to matched population rates of disease. We also investigated the average relatedness of cases compared to the average relatedness of sets of matched controls. Outcome measures include estimation of relative risk and excessive relatedness as measured by a Genealogical Index of Familiality (GIF) analysis. RESULTS We analyzed 307 individuals with PD, and their first- through fifth-degree relatives. Approximately 0.12% of the population had PD, 95% of these were diagnosed over the age of 30 years (age range: 10-92 years), and 1.3% of PD probands had a comorbid diagnosis of DD. RR estimates for PD were significant for first- and fifth-degree relatives. RR estimates for DD were significant only for probands. The average relatedness of cases was significantly greater than matched controls, even after removing first- and second-degree relatives. We also found that 74.9% of identified PD probands belonged to pedigrees with a statistical excess of PD. CONCLUSION Despite the low prevalence of PD in our healthcare records, the results provide evidence that support a genetic contribution to at least a subset of PD cases.
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Affiliation(s)
- Kristina L Allen-Brady
- Genetic Epidemiology, Department of Epidemiology, University of Utah, Salt Lake City, Utah, USA
| | - Michael B Christensen
- Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | | | - Alexander W Pastuszak
- Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah, USA
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Twitchell DK, Christensen MB, Hackett G, Morgentaler A, Saad F, Pastuszak AW. Examining Male Predominance of Severe COVID-19 Outcomes: A Systematic Review. Androg Clin Res Ther 2022; 3:41-53. [PMID: 36199281 PMCID: PMC9527649 DOI: 10.1089/andro.2022.0006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/13/2022] [Indexed: 05/26/2023]
Abstract
Although not universal, many epidemiological data sources signal that a higher proportion of males than females with confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections have adverse outcomes, such as intensive care unit (ICU) admission and death. Though likely multifactorial, the various hypotheses that have been proposed as underlying factors behind this trend are related to greater smoking prevalence among males, testosterone (T) deficiency causing an inflammatory storm, androgen-driven pathogenesis of SARS-CoV-2, a protective effect of estrogen in females, and inborn errors of cytokine immunity. This review aims at examining the evidence and at assessing the likelihood that the factors being investigated are contributory to the reported trend of male predominance of severe COVID-19 cases. Sources were obtained using the PubMed database and were selected based on their relevance to one of the primary hypotheses attempting to explain the strong male sex bias of severe SARS-CoV-2 infections. Emphasis was placed on meta-analyses and population-based studies. Sources are current through February 22, 2022. A severe COVID-19 case or outcome is defined in this review as a progression of the SARS-CoV-2 virus that results in either admission to an ICU for management of symptoms and clinical stabilization or which leads to death. Although the trend of male predominance of severe COVID-19 cases is likely multifactorial, the hypothesis of T deficiency causing an inflammatory storm has support from many studies with limited conflicting evidence. An inborn error in cytokine immunity is also well supported, but it needs more studies to add support to the hypothesis. The immunologic protective effect of estrogen is supported by multiple studies, but it also has conflicting evidence. It appears less likely that the trend is caused solely by an increased prevalence of smoking among males or an androgen-driven pathogenesis, based on the extent of conflicting evidence.
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Affiliation(s)
| | - Michael B. Christensen
- Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Geoffrey Hackett
- Department of Men's Health, Little Aston Hospital, Sutton Coldfield, United Kingdom
| | - Abraham Morgentaler
- Division of Urology, Department of Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Farid Saad
- Department of Men's Health Research, Gulf Medical University, Ajman, UAE
| | - Alexander W. Pastuszak
- Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah, USA
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Christensen MB, Vibel T, Hilliard AJ, Kruk MB, Pawłowski K, Hryniuk D, Rzążewski K, Kristensen MA, Arlt JJ. Observation of Microcanonical Atom Number Fluctuations in a Bose-Einstein Condensate. Phys Rev Lett 2021; 126:153601. [PMID: 33929256 DOI: 10.1103/physrevlett.126.153601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Quantum systems are typically characterized by the inherent fluctuation of their physical observables. Despite this fundamental importance, the investigation of the fluctuations in interacting quantum systems at finite temperature continues to pose considerable theoretical and experimental challenges. Here we report the characterization of atom number fluctuations in weakly interacting Bose-Einstein condensates. Technical fluctuations are mitigated through a combination of nondestructive detection and active stabilization of the cooling sequence. We observe fluctuations reduced by 27% below the canonical expectation for a noninteracting gas, revealing the microcanonical nature of our system. The peak fluctuations have near linear scaling with atom number ΔN_{0,p}^{2}∝N^{1.134} in an experimentally accessible transition region outside the thermodynamic limit. Our experimental results thus set a benchmark for theoretical calculations under typical experimental conditions.
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Affiliation(s)
- M B Christensen
- Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - T Vibel
- Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - A J Hilliard
- Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - M B Kruk
- Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - K Pawłowski
- Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - D Hryniuk
- Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - K Rzążewski
- Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - M A Kristensen
- Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - J J Arlt
- Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
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Graversen DS, Christensen MB, Pedersen AF, Carlsen AH, Bro F, Christensen HC, Vestergaard CH, Huibers L. Safety, efficiency and health-related quality of telephone triage conducted by general practitioners, nurses, or physicians in out-of-hours primary care: a quasi-experimental study using the Assessment of Quality in Telephone Triage (AQTT) to assess audio-recorded telephone calls. BMC Fam Pract 2020; 21:84. [PMID: 32386511 PMCID: PMC7211335 DOI: 10.1186/s12875-020-01122-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 03/04/2020] [Indexed: 11/10/2022]
Abstract
Background To explore and compare safety, efficiency, and health-related quality of telephone triage in out-of-hours primary care (OOH-PC) services performed by general practitioners (GPs), nurses using a computerised decision support system (CDSS), or physicians with different medical specialities. Methods Natural quasi-experimental cross-sectional study conducted in November and December 2016. We randomly selected 1294 audio-recorded telephone triage calls from two Danish OOH-PC services triaged by GPs (n = 423), nurses using CDSS (n = 430), or physicians with different medical specialities (n = 441). An assessment panel of 24 physicians used a validated assessment tool (Assessment of Quality in Telephone Triage - AQTT) to assess all telephone triage calls and measured health-related quality, safety, and efficiency of triage. Results The relative risk (RR) of poor quality was significantly lower for nurses compared to GPs in four out of ten items regarding identifying and uncovering of problems. For most items, the quality tended to be lowest for physicians with different medical specialities. Compared to calls triaged by GPs (reference), the risk of clinically relevant undertriage was significantly lower for nurses, while physicians with different medical specialties had a similar risk (GP: 7.3%, nurse: 3.7%, physician: 6.1%). The risk of clinically relevant overtriage was significantly higher for nurses (9.1%) and physicians with different medical specialities (8.2%) compared to GPs (4.3%). GPs had significantly shorter calls (mean: 2 min 57 s, SD: 105 s) than nurses (mean: 4 min 44 s, SD: 168 s). Conclusions Our explorative study indicated that nurses using CDSS performed better than GPs in telephone triage on a large number of health-related items, had a lower level of clinically relevant undertriage, but were perceived less efficient. Calls triaged by physicians with different medical specialities were perceived less safe and less efficient compared to GPs. Differences in the organisation of telephone triage may influence the distribution of workload in primary and secondary OOH services. Future research could compare the long-term outcomes following a telephone call to OOH-PC related to safety and efficiency.
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Affiliation(s)
- D S Graversen
- Research Unit for General Practice, Aarhus, Bartholins Allé 2, 8000, Aarhus C, Denmark. .,Department of Public Health, Aarhus University, Bartholins Allé 2, 8000, Aarhus C, Denmark.
| | - M B Christensen
- Research Unit for General Practice, Aarhus, Bartholins Allé 2, 8000, Aarhus C, Denmark.,Department of Public Health, Aarhus University, Bartholins Allé 2, 8000, Aarhus C, Denmark
| | - A F Pedersen
- Research Unit for General Practice, Aarhus, Bartholins Allé 2, 8000, Aarhus C, Denmark.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - A H Carlsen
- Research Unit for General Practice, Aarhus, Bartholins Allé 2, 8000, Aarhus C, Denmark
| | - F Bro
- Research Unit for General Practice, Aarhus, Bartholins Allé 2, 8000, Aarhus C, Denmark.,Department of Public Health, Aarhus University, Bartholins Allé 2, 8000, Aarhus C, Denmark
| | - H C Christensen
- Emergency Medical Services, Copenhagen, Denmark.,The National Clinical Databases (RKKP), Copenhagen, Denmark
| | - C H Vestergaard
- Research Unit for General Practice, Aarhus, Bartholins Allé 2, 8000, Aarhus C, Denmark
| | - L Huibers
- Research Unit for General Practice, Aarhus, Bartholins Allé 2, 8000, Aarhus C, Denmark
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Patel DP, Christensen MB, Hotaling JM, Pastuszak AW. Erectile Dysfunction and Peyronie’s Disease: Genetic Diseases? Eur Urol Focus 2020; 6:572-574. [DOI: 10.1016/j.euf.2019.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 08/15/2019] [Indexed: 02/06/2023]
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7
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Chao MR, Howe KA, Pierce JL, Stark AC, Smith ME, Christensen MB. Morphometric Differences in the Recurrent Laryngeal Nerve in Patients with Vocal Fold Paralysis. Ann Otol Rhinol Laryngol 2019; 129:32-38. [PMID: 31409113 DOI: 10.1177/0003489419870829] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Injury to the recurrent laryngeal nerve (RLN), if severe enough, can result in vocal fold paralysis. Reinnervation surgery can improve patient outcomes, but previous studies have reported a negative correlation between time since onset of paralysis and surgical outcomes. The ability of the paralyzed nerve to serve as a conduit for donor nerve fibers may be a factor in the success of reinnervation; however, changes in RLN composition after paralysis have not been well studied. Therefore, we investigated the morphometric composition of explanted RLN sections from patients who had experienced vocal fold paralysis for varying length of times. METHODS Nine nerve sections from unilateral vocal fold paralysis (UVP) patients and seven control nerve sections were analyzed for morphometric parameters including fascicular area, fiber count, fiber density, fiber packing, mean g-ratio, and fiber diameter distribution. Nerves from UVP patients were also compared as a function of time since UVP onset. RESULTS In comparison to control nerves, paralyzed nerves were found to have significantly lower fiber densities and fiber packing, higher mean g-ratio values, and a shift in diameter distributions toward smaller diameter fibers. With respect to paralysis duration, no significant differences were observed except in fiber diameter distributions, where those with paralysis for >2 years had distributions that were significantly shifted toward smaller diameter fibers. CONCLUSIONS The morphometric data presented here suggest that correlations between the time since onset of vocal fold paralysis and reinnervation outcomes may be due to fiber size changes in the paralyzed nerve over time.
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Affiliation(s)
- Melissa R Chao
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - Katherine A Howe
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - Jennifer L Pierce
- Department of Communication Sciences and Disorders, University of Utah, Salt Lake City, UT, USA
| | - Amanda C Stark
- National Center for Voice and Speech, University of Utah, Salt Lake City, UT, USA
| | - Marshall E Smith
- Division of Otolaryngology/Head and Neck Surgery, University of Utah, Salt Lake City, UT, USA
| | - Michael B Christensen
- National Center for Voice and Speech, University of Utah, Salt Lake City, UT, USA
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
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8
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Patel DP, Christensen MB, Hotaling JM, Pastuszak AW. A review of inflammation and fibrosis: implications for the pathogenesis of Peyronie's disease. World J Urol 2019; 38:253-261. [PMID: 31190155 DOI: 10.1007/s00345-019-02815-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 05/17/2019] [Indexed: 01/07/2023] Open
Abstract
Peyronie's disease (PD) is a superficial fibrosing disorder that causes penile deformity and can interfere with sexual intercourse and reproduction, as well as diminish quality of life. While the exact mechanism of PD is still being investigated, there is likely a genetic component to the predisposition to penile plaque formation. Ultimately, however, perturbations in normal wound healing and aberrant deposition of extracellular matrix components lead to fibrotic tissue deposition. Fibrosis in PD is regulated by a complex pathway of inflammatory and fibrotic mediators. Currently there are no treatments for PD that address an underlying cause or disease progression. In this review, we provide an overview of the known inflammatory and fibrotic mediators of PD and explore the pathophysiology of other human superficial fibrosing disorders to develop further insights into PD.
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Affiliation(s)
- Darshan P Patel
- Division of Urology, Department of Surgery, Center for Reconstructive Urology and Men's Health, University of Utah School of Medicine, 30 N 1900 E, Rm # 3B420, Salt Lake City, UT, 84132, USA
| | - Michael B Christensen
- Division of Urology, Department of Surgery, Center for Reconstructive Urology and Men's Health, University of Utah School of Medicine, 30 N 1900 E, Rm # 3B420, Salt Lake City, UT, 84132, USA
| | - James M Hotaling
- Division of Urology, Department of Surgery, Center for Reconstructive Urology and Men's Health, University of Utah School of Medicine, 30 N 1900 E, Rm # 3B420, Salt Lake City, UT, 84132, USA
| | - Alexander W Pastuszak
- Division of Urology, Department of Surgery, Center for Reconstructive Urology and Men's Health, University of Utah School of Medicine, 30 N 1900 E, Rm # 3B420, Salt Lake City, UT, 84132, USA.
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9
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Kristensen MA, Christensen MB, Gajdacz M, Iglicki M, Pawłowski K, Klempt C, Sherson JF, Rzążewski K, Hilliard AJ, Arlt JJ. Observation of Atom Number Fluctuations in a Bose-Einstein Condensate. Phys Rev Lett 2019; 122:163601. [PMID: 31075024 DOI: 10.1103/physrevlett.122.163601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Indexed: 06/09/2023]
Abstract
Fluctuations are a key property of both classical and quantum systems. While the fluctuations are well understood for many quantum systems at zero temperature, the case of an interacting quantum system at finite temperature still poses numerous challenges. Despite intense theoretical investigations of atom number fluctuations in Bose-Einstein condensates, their amplitude in experimentally relevant interacting systems is still not fully understood. Moreover, technical limitations have prevented their experimental investigation to date. Here we report the observation of these fluctuations. Our experiments are based on a stabilization technique, which allows for the preparation of ultracold thermal clouds at the shot noise level, thereby eliminating numerous technical noise sources. Furthermore, we make use of the correlations established by the evaporative cooling process to precisely determine the fluctuations and the sample temperature. This allows us to observe a telltale signature: the sudden increase in fluctuations of the condensate atom number close to the critical temperature.
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Affiliation(s)
- M A Kristensen
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - M B Christensen
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - M Gajdacz
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - M Iglicki
- Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
- Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093 Warsaw, Poland
| | - K Pawłowski
- Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - C Klempt
- Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
| | - J F Sherson
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - K Rzążewski
- Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - A J Hilliard
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - J J Arlt
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
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King RE, Lau HK, Zhang H, Sidhu I, Christensen MB, Fowler EW, Li L, Jia X, Kiick KL, Thibeault SL. Biocompatibility and Viscoelastic Properties of Injectable Resilin-Like Polypeptide and Hyaluronan Hybrid Hydrogels in Rabbit Vocal Folds. Regen Eng Transl Med 2019; 5:373-386. [DOI: 10.1007/s40883-019-00094-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Type 2 diabetes mellitus is a common and severe chronic metabolic disease, which confers increased risk of cardiovascular disease and mortality. During the last decade a large number of new drugs within the classes dipeptidyl peptidase 4 (DPP-4) inhibitors (DPP-4Is), glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1RAs) and sodium/glucose cotransporter 2 (SGLT-2) inhibitors (SGLT-2Is) have been developed and tested in nine large-scale cardiovascular outcome trials (CVOTs). Here we review the evidence behind antihyperglycemic treatment of patients with type 2 diabetes with a particular focus on compiling and summarizing the evidence of hard clinical endpoints stemming from these large CVOTs.
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Affiliation(s)
- A M Sørensen
- Department of Clinical Pharmacology, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
| | - M B Christensen
- Department of Clinical Pharmacology, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark and Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
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12
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Bartlett RS, Guille JT, Chen X, Christensen MB, Wang SF, Thibeault SL. Mesenchymal stromal cell injection promotes vocal fold scar repair without long-term engraftment. Cytotherapy 2017; 18:1284-96. [PMID: 27637759 DOI: 10.1016/j.jcyt.2016.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [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: 03/29/2016] [Revised: 07/18/2016] [Accepted: 07/24/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Regenerative medicine holds promise for restoring voice in patients with vocal fold scarring. As experimental treatments approach clinical translation, several considerations remain. Our objective was to evaluate efficacy and biocompatibility of four bone marrow mesenchymal stromal cell (BM-MSC) and tunable hyaluronic acid based hydrogel (HyStem-VF) treatments for vocal fold scar using clinically acceptable materials, a preclinical sample size and a dosing comparison. METHODS Vocal folds of 84 rabbits were injured and injected with four treatment variations (BM-MSC, HyStem-VF, and BM-MSC in HyStem-VF at two concentrations) 6 weeks later. Efficacy was assessed with rheometry, real-time polymerase chain reaction (RT-PCR) and histology at 2, 4 and 10 weeks following treatment. Lung, liver, kidney, spleen and vocal folds were screened for biocompatibility by a pathologist. RESULTS AND DISCUSSION Persistent inflammation was identified in all hydrogel-injected groups. The BM-MSC alone treatment appeared to be the most efficacious and safe, providing an early resolution of viscoelasticity, gene expression consistent with desirable extracellular matrix remodeling (less fibronectin, collagen 1α2, collagen 3, procollagen, transforming growth factor [TGF]β1, alpha smooth muscle actin, interleukin-1β, interleukin-17β and tumor necrosis factor [TNF] than injured controls) and minimal inflammation. Human beta actin expression in BM-MSC-treated vocal folds was minimal after 2 weeks, suggesting that paracrine signaling from the BM-MSCs may have facilitated tissue repair.
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Affiliation(s)
- R S Bartlett
- Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - J T Guille
- Department of ENT and Head and Neck Surgery, University Hospital of Pointe à Pitre, Guadeloupe, French West Indies
| | - X Chen
- Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - M B Christensen
- National Center for Voice and Speech, University of Utah, Salt Lake City, Utah, USA
| | - S F Wang
- Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - S L Thibeault
- Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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Ebert JF, Huibers L, Lippert FK, Christensen B, Christensen MB. Development and evaluation of an "emergency access button" in Danish out-of-hours primary care: a study protocol of a randomized controlled trial. BMC Health Serv Res 2017; 17:379. [PMID: 28566087 PMCID: PMC5452428 DOI: 10.1186/s12913-017-2308-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 05/15/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Out-of-hours (OOH) health care for acute medical problems is often challenged by long waiting time for callers in need of advice and triage. Allowing patients to bypass the OOH telephone waiting line may increase patient satisfaction and provide them with a feeling of safety. We aimed to develop an "emergency access button" enabling patients to bypass the normal telephone waiting line in out-of-hours primary care (OOH-PC) if they perceive their condition to be critical and to evaluate the effect of introducing the button in terms of patient satisfaction and their feeling of safety. METHODS All patients calling the OOH-PC in two different Danish health care regions during three months will be included in this randomized controlled trial. Data will be collected through two questionnaires developed for this study: a pop-up questionnaire on the relevance of bypassing the normal waiting line to be completed by triage professionals after patient contact and a paper/electronic questionnaire on perceived safety and satisfaction with the emergency access button to be completed by the callers. These questionnaires were developed and validated using external and internal expert feedback, focus group interviews and a two-week field test. The study will be conducted over three months with an estimated user-rate of the emergency access button of 3%. DISCUSSION We have developed an emergency access button and we now want to investigate whether this new option will influence upon the level of satisfaction and the feeling of safety in the calling patients. Additionally, the study will reveal the assessed relevance of the decision to bypass the line by triage professionals. TRIAL REGISTRATION Registered as NCT02572115 at Clinicaltrials.gov on October 5th 2015.
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Affiliation(s)
- J F Ebert
- Section for General Medical Practice, Department of Public Health, Aarhus University, Bartholins Allé 2, DK-8000, Aarhus C, Denmark. .,Research Unit for General Practice, Department of Public Health, Aarhus University, Bartholins Allé 2, DK-8000, Aarhus C, Denmark.
| | - L Huibers
- Section for General Medical Practice, Department of Public Health, Aarhus University, Bartholins Allé 2, DK-8000, Aarhus C, Denmark.,Research Unit for General Practice, Department of Public Health, Aarhus University, Bartholins Allé 2, DK-8000, Aarhus C, Denmark
| | - F K Lippert
- Emergency Medical Services Copenhagen, The Capital Region of Denmark, Telegrafvej 5, DK-2750, Ballerup, Copenhagen, Denmark
| | - B Christensen
- Section for General Medical Practice, Department of Public Health, Aarhus University, Bartholins Allé 2, DK-8000, Aarhus C, Denmark
| | - M B Christensen
- Section for General Medical Practice, Department of Public Health, Aarhus University, Bartholins Allé 2, DK-8000, Aarhus C, Denmark.,Research Unit for General Practice, Department of Public Health, Aarhus University, Bartholins Allé 2, DK-8000, Aarhus C, Denmark
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14
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Viitanen SJ, Lappalainen AK, Christensen MB, Sankari S, Rajamäki MM. The Utility of Acute-Phase Proteins in the Assessment of Treatment Response in Dogs With Bacterial Pneumonia. J Vet Intern Med 2016; 31:124-133. [PMID: 28032360 PMCID: PMC5259651 DOI: 10.1111/jvim.14631] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 10/18/2016] [Accepted: 11/09/2016] [Indexed: 12/19/2022] Open
Abstract
Background Acute‐phase proteins (APPs) are sensitive markers of inflammation, and serum C‐reactive protein (CRP) recently has been shown to be a useful diagnostic marker in dogs with bacterial pneumonia (BP). In humans with community‐acquired pneumonia, APPs also have great utility as follow‐up markers aiding in the assessment of treatment response. Objectives The aim of our study was to investigate the applicability of APPs as markers of treatment response in dogs with BP. Animals Nineteen dogs diagnosed with BP and 64 healthy dogs. Methods The study was conducted as a prospective longitudinal observational study. Serum CRP, serum amyloid A (SAA), and haptoglobin concentrations were followed during a natural course of BP. Normalization of serum CRP was used to guide the duration of antibiotic treatment (treatment was stopped 5–7 days after CRP normalized) in 8 of 17 dogs surviving to discharge; 9 of 17 dogs were treated according to conventional recommendations. Results All measured APPs initially were significantly increased, but the magnitude of increase was not correlated to disease severity. C‐reactive protein and SAA concentrations decreased rapidly after initiation of antimicrobial treatment. When normalization of serum CRP was used to guide the duration of antibiotic treatment, treatment duration was significantly (P = .015) decreased without increasing the number of relapses. Conclusions and Clinical Importance Serum CRP and SAA reflected the recovery process well and therefore may be used as markers of treatment response. According to the results, the normalization of serum CRP may be used to guide the duration of antibiotic treatment in dogs with BP.
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Affiliation(s)
- S J Viitanen
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - A K Lappalainen
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - M B Christensen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - S Sankari
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - M M Rajamäki
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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Abstract
The problem of acoustic feedback in hearing aids could be solved potentially by applying a compliant hydrogel to the outer surface that would conform to the ear canal and block feedback. With this objective, several formulations of hydrogels were developed and their swelling and mechanical properties investigated. Hydrogel formulations were polymerized from hydroxyethyl methacrylate (HEMA) and N-vinyl-pyrrolidone (NVP), with various photo-initiators, crosslinkers, and swelling agents. The hydrogel that swelled most rapidly and yet remained undissolved in water had a monomer composition of 40 mol% HEMA, 60 mol% NVP, with 1 wt% polyethylene glycol dimethacrylate as a crosslinker, and 0.5 wt% 2,2-dimethoxy-2-phenyl-acetophenone as the photo-initiator. The tensile modulus, strength, hardness, and durability of the dry hydrogels were not a strong function of composition. In the swollen state, the mechanical properties were much reduced. The potential use of these materials on hearing aids has been discussed in this article.
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Affiliation(s)
- Sung-Il Choi
- Chemical Engineering Department, Brigham Young University, Provo, UT 84602, USA
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16
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Abstract
The aim of the present study was to investigate the impact of static contraction of the shoulder and neck muscles on muscle tenderness and headache in patients with tension-type headache. Twenty patients with frequent episodic tension-type headache and 20 healthy age- and sex-matched controls were examined using a placebo-controlled cross-over design. The subjects performed static contraction of the trapezius muscles (active procedure) or the anterior tibial muscles (placebo procedure) with 10% of maximal force for 30 min. Total tenderness score, local tenderness score and headache intensity were evaluated before and after the static work. Changes in headache intensity were followed for 24 h. Pericranial tenderness increased significantly more in patients than in controls after the active procedure ( P = 0.04). The increase in pericranial tenderness tended to be higher after the active procedure than after the placebo procedure in patients ( P = 0.08) and in controls ( P = 0.07). Sixty per cent of the patients and 20% of the healthy controls developed headache after the active procedure. Fifty per cent of the patients and none of the controls developed headache after the placebo procedure. There was no significant difference in headache development between the active and the placebo procedure in patients or controls. These findings demonstrate that tension-type headache patients are more liable to develop shoulder and neck pain in response to static exercise than healthy controls.
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Affiliation(s)
- M B Christensen
- Danish Headache Centre and Department of Neurology, Glostrup Hospital, University of Copenhagen, Denmark.
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17
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Woo JH, King SN, Hoffman H, Dailey S, Wang S, Christensen MB, Thibeault SL. MERS versus Standard Surgical Approaches for Porcine Vocal Fold Scarring with Adipose Stem Cell Constructs. Otolaryngol Head Neck Surg 2016; 155:612-23. [PMID: 27165681 DOI: 10.1177/0194599816645772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 04/01/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Cells, scaffold, and surgical approaches are important for regeneration of the lamina propria of the scarred vocal fold (VF). Microendoscopy of Reinke's space (MERS) is a surgical approach used to access the lamina propria. The present study evaluated MERS in the treatment of VF scarring as compared with standardized approaches for the treatment of VF scarring with adipose stem cell constructs. STUDY DESIGN Animal study. SETTING Academic center. SUBJECTS AND METHODS VF injury was performed bilaterally to induce scarring in 20 pigs. Eight weeks after injury, pigs were classified into no treatment, minithyrotomy, VF injection, VF incision/dissection, and MERS. All groups (except control) were implanted with adipose stem cell and hyaluronan. Four weeks after treatment, histology for collagen, hyaluronan, and fibronectin; mRNA expression for α-smooth muscle actin, tumor growth factor β1, collagen 1α1, collagen 3α1, matrix metalloproteinase 2, basic fibroblast growth factor, and hepatocyte growth factor; and tissue rheology were evaluated. RESULTS Differences were measured among surgical approaches for protein levels of collagen, hyaluronan, and fibronectin (P = .0133, P < .0001, and P = .0025, respectively). Fibroblast growth factor, collagen 1α1, and matrix metalloproteinase 2 transcript levels were different among treatment groups (P = .003, P = .0086, and P = .014, respectively), while no differences were measured for α-smooth muscle actin, tumor growth factor β1, hepatocyte growth factor, and collagen 3α1. Rheologically, significant differences were not measured between groups. CONCLUSION MERS is a promising surgical approach for the treatment of VF scarring, optimizing the placement of implanted biomaterials.
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Affiliation(s)
- Joo Hyun Woo
- Department of Otorhinolaryngology-Head and Neck Surgery, Gil Medical Center, Gachon University, Incheon, Korea
| | - Suzanne N King
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, USA
| | - Henry Hoffman
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA
| | - Seth Dailey
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sarah Wang
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | | | - Susan L Thibeault
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Christensen MB, Wark HA, Hutchinson DT. A histological analysis of human median and ulnar nerves following implantation of Utah slanted electrode arrays. Biomaterials 2016; 77:235-42. [DOI: 10.1016/j.biomaterials.2015.11.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 01/30/2023]
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Christensen MB, Wolchok JC, Klemuk SA, Titze IR. Development of a bilayer ring system for achieving high strain in commercial rheometers. J Biomech 2015; 48:3512-6. [PMID: 26228712 DOI: 10.1016/j.jbiomech.2015.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 07/02/2015] [Accepted: 07/13/2015] [Indexed: 11/16/2022]
Abstract
Mechanical stimulation of cell cultures has been shown be an effective means of enhancing ECM production. ECM produced from vocal fold fibroblast cultures has the potential for therapeutic use for vocal fold repair. However, current bioreactor designs generally fail to produce physiological relevant frequency and strain values. Here we present an approach for using commercial oscillatory rheometers and an elastic ring bilayer system to produce physiologically relevant strain values at frequencies in the range of 20-100 Hz. We demonstrate the ability to target specific strain and frequency values by manipulating system parameters, and also show that it is possible to maintain high oscillatory strains for extended periods of time. Such a system could be used to mechanically stimulate cell cultures contained within gel carrier systems and has the potential to be extended to other applications requiring high strains at low frequencies.
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Affiliation(s)
- Michael B Christensen
- The National Center for Voice and Speech, University of Utah, 136 South Main Street, Suite 320, Salt Lake City, UT 84101, USA; Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Rm 3100, Salt Lake City, UT 84112, USA.
| | - Jeffrey C Wolchok
- Department of Biomedical Engineering, University of Arkansas, 317 Engineering Hall, Fayetteville, AR 72701, USA
| | - Sarah A Klemuk
- The National Center for Voice and Speech, University of Utah, 136 South Main Street, Suite 320, Salt Lake City, UT 84101, USA; Department of Communication Sciences and Disorders, University of Iowa, 324 SHC, Iowa City, IA 52242, USA
| | - Ingo R Titze
- The National Center for Voice and Speech, University of Utah, 136 South Main Street, Suite 320, Salt Lake City, UT 84101, USA
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Nolta NF, Christensen MB, Crane PD, Skousen JL, Tresco PA. BBB leakage, astrogliosis, and tissue loss correlate with silicon microelectrode array recording performance. Biomaterials 2015; 53:753-62. [DOI: 10.1016/j.biomaterials.2015.02.081] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/13/2015] [Accepted: 02/19/2015] [Indexed: 10/23/2022]
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Christensen MB, Tresco PA. Differences Exist in the Left and Right Sciatic Nerves of Naïve Rats and Cats. Anat Rec (Hoboken) 2015; 298:1492-501. [PMID: 25857635 DOI: 10.1002/ar.23161] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 02/02/2015] [Accepted: 02/09/2015] [Indexed: 12/14/2022]
Abstract
The sciatic nerve of rats and cats is commonly used in experimental models of peripheral nerve injury and repair, as well as experiments involving peripheral nerve electrode implantation. In such experiments, morphometric parameters from the implanted nerve are commonly evaluated and compared to control values obtained from the contralateral nerves. However, this may not be an appropriate approach as differences may naturally exist in the structure of the two nerves owing to developmental or behavioral asymmetry. Additionally, in the cat, baseline values for standard morphometric parameters are not well established. In this study, we characterized fascicle area, fiber count, fiber density, fiber packing, mean g-ratio, and fiber diameter distributions in the rat and cat, as well as investigated the potential for naturally occurring sided differences in these parameters in both species. We also investigated whether animal age or location along the nerve influenced these parameters. We found that sided or left/right leg differences exist in some parameters in both the rat and the cat, calling into question the validity of using the contralateral nerve as a control. We also found that animal age and location along the nerve can make significant differences in the parameters tested, establishing the importance of using control nerves from age- and behaviorally matched animals whose morphometric parameters are collected and compared from the same location.
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Affiliation(s)
- Michael B Christensen
- Department of Bioengineering, College of Engineering, University of Utah, Salt Lake City, Utah
| | - Patrick A Tresco
- Department of Bioengineering, College of Engineering, University of Utah, Salt Lake City, Utah
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22
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Christensen MB, Oberg K, Wolchok JC. Tensile properties of the rectal and sigmoid colon: a comparative analysis of human and porcine tissue. Springerplus 2015; 4:142. [PMID: 25977885 PMCID: PMC4414857 DOI: 10.1186/s40064-015-0922-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 03/11/2015] [Indexed: 01/19/2023]
Abstract
For many patients, rectal catheters are an effective means to manage bowel incontinence. Unfortunately, the incidence of catheter leakage in these patients remains troublingly high. Matching the mechanical properties of the catheter and the surrounding tissue may improve the catheter seal and reduce leakage. However, little data is available on the mechanical properties of colorectal tissue. Therefore, our group examined the mechanical properties of colorectal tissue obtained from both a common animal model and humans. Uniaxial tension tests were performed to determine the effects of location, orientation, and species (porcine and human) on bowel tissue tensile mechanical properties. Bowel tissue ultimate strength, elongation at failure, and elastic modulus were derived from these tests and statistically analyzed. Ultimate tensile strength (0.58 MPa, 0.87 MPa), elongation at failure (113.19%, 62.81%), and elastic modulus (1.83 MPa, 5.18 MPa) for porcine and human samples respectively exhibited significant differences based on species. Generally, human tissues were stronger and less compliant than their porcine counterparts. Furthermore, harvest site location and testing orientation significantly affected several mechanical properties in porcine derived tissues, but very few in human tissues. The data suggests that porcine colorectal tissue does not accurately model human colorectal tissue mechanical properties. Ultimately, the tensile properties reported herein may be used to help guide the design of next generation rectal catheters with tissue mimetic properties, as well as aid in the development of physical and computer based bowel models.
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Affiliation(s)
- Michael B Christensen
- Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, 36 S Wasatch Dr. Rm 3100, Salt Lake City, UT 84112 USA
| | - Kevin Oberg
- Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, 36 S Wasatch Dr. Rm 3100, Salt Lake City, UT 84112 USA
| | - Jeffrey C Wolchok
- Department of Biomedical Engineering, University of Arkansas, 120 Engineering Hall, Fayetteville, AR 72701 USA
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Mathews KS, Wark HA, Warren DJ, Christensen MB, Nolta NF, Cartwright PC, Normann RA. Acute Monitoring of Genitourinary Function Using Intrafascicular Electrodes: Selective Pudendal Nerve Activity Corresponding to Bladder Filling, Bladder Fullness, and Genital Stimulation. Urology 2014; 84:722-9. [DOI: 10.1016/j.urology.2014.05.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 05/01/2014] [Accepted: 05/13/2014] [Indexed: 11/15/2022]
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Christensen MB, Lawlor DA, Gaunt TR, Howell WM, Howell MW, Davey Smith G, Ebrahim S, Day INM. Genotype of galectin 2 (LGALS2) is associated with insulin-glucose profile in the British Women's Heart and Health Study. Diabetologia 2006; 49:673-7. [PMID: 16468038 DOI: 10.1007/s00125-006-0145-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [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] [Received: 10/10/2005] [Accepted: 11/29/2005] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS It has been suggested that the gene encoding lymphotoxin-alpha (LTA) is associated with insulin resistance, and genetic association studies in the LTA region offer some support for this. However, LTA is in linkage disequilibrium with both the HLA gene cluster and the gene encoding TNF-alpha, making inferences about causality difficult. In this study, we used the galectin 2 (LGALS2) genotype, which affects LTA secretion but is located on another chromosome than the HLA gene cluster or TNF, to examine the relationship between the LTA pathway and traits of the metabolic syndrome. SUBJECTS A cross-sectional genetic association study was carried out in 3,272 British women of European origin who were aged 60 to 79 years and were randomly selected from the community. RESULTS Fasting plasma glucose and serum insulin were statistically significantly associated with LGALS2 rs7291467, with this association being independent of BMI and WHR. The mean difference in fasting insulin per minor allele was -4% (p=0.01 for trend by allele) and the mean per minor allele difference in fasting glucose was -2% (p=0.02 for trend by allele). When women with known diabetes were excluded from the analyses the findings did not differ from those for the whole cohort. CONCLUSIONS/INTERPRETATION Our findings for the physically unlinked LGALS2, invite further study of LGALS2 specifically and the LTA pathway generally for their influence on glucose-insulin regulation.
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Affiliation(s)
- M B Christensen
- Human Genetics Division School of Medicine, Southampton University Hospital, Southampton SO16 6YD, UK
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Vedsted P, Christensen MB. Frequent attenders in general practice care: A literature review with special reference to methodological considerations. Public Health 2005; 119:118-37. [PMID: 15694959 DOI: 10.1016/j.puhe.2004.03.007] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Revised: 03/04/2004] [Accepted: 03/26/2004] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To describe the basis on which our knowledge of frequent attendance in general practice rests and to propose recommendations for further research on frequent attenders (FAs). DESIGN The literature review (finished February 2004) encompassed peer-reviewed articles in English describing contacts with general practice in terms of frequency. Searches were performed in the Medline, CINAHL, EMBASE, PsycINFO, Social Sciences Expanded Index and ISI Citation databases with additional searches in reference lists and the 'related articles' function in the ISI Citation database and Medline. SETTING General practice. SUBJECTS Sixty-one articles (54 studies). MEASURES The articles were assessed according to the following design variables: setting; definition of FAs; sampling; sample size; control groups; study aim; study design; data sources; effect measure; and main results. RESULTS There was no generally accepted definition of frequent attendance. Research designs differed substantially. Eight articles gave sufficient information on all design variables. The top 10% of attenders accounted for 30-50% of all contacts, and up to 40% of FAs were still FAs the following year. More than 50% of FAs had a physical disease, more than 50% of FAs suffered from psychological distress, social factors (low social support, unemployment, divorce) were associated with frequent attendance in more than 50% of FAs, multiproblems (physical, psychological and social) were found in one-third of FAs, and frequent attendance was associated with increasing age and female gender. CONCLUSION The diversity of designs, definitions and methods in the current literature on FAs in general practice hampers comparison of their precision, validity and generalizability, and calls for cautious interpretation and adoption of a common, generally acceptable definition in future studies.
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Affiliation(s)
- P Vedsted
- The Research Unit and Department of General Practice, University of Aarhus, Vennelyst Boulevard 6, DK-8000 Aarhus C, Denmark.
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Abstract
OBJECTIVE A reorganisation of the out-of-hours general practice service in Denmark was launched in January 1992. The biggest changes were in a mandatory telephone triage staffed by GPs and the replacement of small rota systems with county-based health centres. We aimed to analyse the effect of this out-of-hours reform on the number of contacts with the casualty wards. DESIGN A register-based ecologic time-trend study of the mean number of annual contacts per inhabitant from 1988 to 1997. SETTING The County of Aarhus. SUBJECTS All 630000 inhabitants in the county. MAIN OUTCOME MEASURES Mean number of annual contacts with casualty wards per inhabitant. Intercepts derived from two regression models. RESULTS The mean number of contacts with casualty wards rose significantly during the whole period. Given this constant increase in contact rates, a regression model showed that the increase in the attendance rate with casualty wards after the reform was statistically insignificant. CONCLUSIONS The decrease in the total number of contacts with the out-of-hours primary health care after the reform was not met by a corresponding increase in casualty ward contacts. A clear-cut significant increase in the use of casualty wards following the out-of-hours reform could not be demonstrated.
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Affiliation(s)
- P Vedsted
- Research Unit and Department of General Practice, University of Aarhus, Denmark.
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27
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Kjeldsen HC, Ovesen LC, Christensen MB, Olesen F. [Are out of hours contacts with physicians necessary? Assessment by physicians on call and by patients]. Ugeskr Laeger 2000; 162:2032-6. [PMID: 10815518] [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: 02/16/2023]
Abstract
Patients and GPs were asked about necessity and possible prevention of contacts to the out of hour service. 4187 (83.9%) of the GP questionnaires and 1493 (52.3%) of the patient questionnaires were returned. According to the GPs 25% of the contacts were not necessary and 5% were not necessary according to the patients. Patients and GPs agreed that contacts concerning old people were most necessary. GPs assessed contacts concerning children relatively more necessary. Patients assessed contacts concerning middle-aged relatively more necessary. Frequent users were assessed less necessary according to GPs but more necessary according to the users themselves. Many contacts could have been prevented according to both GPs and patients--especially within the first five hours of the service. Concordance between a patient's and a GPs answer was bad (kappa = 0.0-0.2). Concordance between the GPs answering the phone and the GPs examining the patient was only slightly better (kappa = 0.1-0.3).
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Nielsen LP, Bjerke T, Christensen MB, Skamling M, Peterson CG, Mygind N, Dahl R. Eosinophil markers in seasonal allergic rhinitis. Intranasal fluticasone propionate inhibits local and systemic increases during the pollen season. Allergy 1998; 53:778-85. [PMID: 9722227] [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: 02/08/2023]
Abstract
BACKGROUND The purpose was to study activation markers of the eosinophil granulocytes in seasonal allergic rhinitis, and the impact of topical steroid therapy thereupon. METHODS Sixty-three rhinitis patients with monoallergy to grass were examined before and at peak pollen season. Blood eosinophil count, eosinophil cationic protein (ECP), and eosinophil peroxidase (EPO) in serum and nasal lavage fluid were measured. During the season, patients were randomized to treatment with intranasal fluticasone propionate 0.1 mg o.d. (n=26), 0.2 mg o.d. (n=25), or placebo (n=12). Six healthy persons served as controls. RESULTS During the season, all parameters, except nasal lavage ECP, increased in the placebo group (P<0.001-P<0.05). Significant differences were seen between the steroid groups and the placebo group for all parameters (P<0.001-P<0.05). Higher eosinophil count (P<0.05), serum EPO (P<0.02), and nasal lavage EPO (P<0.05) were found in patients before season than in controls. The following winter, 44 patients returned for repeated measurement. Lower levels of nasal lavage EPO were observed for patients than levels at the beginning of the season (P<0.0001). CONCLUSIONS Intranasal fluticasone propionate reduced inflammation of the nasal mucosa, demonstrated locally by nasal lavage ECP and EPO, and systemically by blood eosinophils, serum ECP, and serum EPO. EPO seemed more sensitive than ECP as indicator of allergic inflammation. EPO demonstrated some perennial eosinophil activity in hay fever patients, increasing locally during spring.
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Affiliation(s)
- L P Nielsen
- Department of Respiratory Diseases, Aarhus University Hospital, Denmark
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Abstract
OBJECTIVE Five years after its introduction, to evaluate the 1992 reform in the out of hours service in Denmark. DESIGN Comparison of data before and after reform. Data were collected from published reports, Danish national health statistics, and the Danish trade union for general practitioners. SETTING Denmark. MAIN OUTCOME MEASURES Number of out of hours services; workload of general practitioners; cost of the service; patient satisfaction. RESULTS Five years after the reform, the percentage of telephone consultations had almost doubled, to 48%. Consultations in doctors' surgeries were relatively unchanged, but home visits were much reduced, to 18%. The percentage of doctors who worked 5 hours or more out of hours per week dropped from about 70% to about 50%. Overall patient satisfaction in 1995 was high (72%). CONCLUSION The organisation of the out of hours service, with a fully trained general practitioner in a telephone triage function, is working satisfactorily. Many calls that previously would have required home visits are now dealt with by telephone or through consultations. The out of hours workload for general practitioners has decreased considerably.
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Affiliation(s)
- M B Christensen
- Research Unit for General Practice, University of Aarhus, 2 DK-8000 Aarhus C, Denmark.
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Christensen MB, Olesen F. [Prescription of strong analgesics in the out-of-hours general practice in the county of Aarhus]. Ugeskr Laeger 1997; 159:2381-5. [PMID: 9163114] [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: 02/04/2023]
Abstract
The article describes the ordination of opioid analgesics in the out-of-hours general practice service to patients with pain due to an illness lasting for more than two days. The physicians working out-of-hours duty and the patient's GP answered a questionnaire. The research includes 227 contacts. The results showed that the main diagnoses were: migraine/headache (33%), angina pectoris (19%) and back-pain (11%). The physicians estimated 33% of the contacts to be "less necessary" or "unnecessary". In 78% of the cases the GPs "agreed" or "almost agreed" with the deputizing doctors' use of opioids. In most of the cases the patients' usual GPs agreed with the treatment prescribed by the deputizing doctors. There seems to be a disagreement between the GPs and the Danish National Board of Health about the principles concerning the use of opioids.
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Christensen MB, Olesen F. [Use of on-call service by patients with pain in the county of Aarhus]. Ugeskr Laeger 1997; 159:2375-80. [PMID: 9163113] [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: 02/04/2023]
Abstract
The aim of the study was to describe the numbers and other characteristics of patients who contacted the general practitioners (GP) out-of-hours on-call service with pain as the most important or major contributing reason for the contact. Data were collected from a questionnaire entered in the GPs' computer system. About 80% of the GPs participated. Over a 14 day period 10,653 contacts were registered, and of these 4718 were analyzed, consisting of 2080 telephone consultations, 1316 consultations and 1322 home visits. The results showed that 30% of the telephone calls, 37% of the consultations and 41% of the home visits concerned a patient with pain problems. Of these contacts concerning pain patients, the physicians estimated that 33% of the consultations and home visits and 55% of the telephone calls were "less necessary" or "unnecessary". It is concluded that pain is a major reason for contacting the GPs' on-call service, and that physicians deem many of these contacts "less necessary" of "unnecessary". Better information to citizens and better education of the physicians might enable some of these contacts to be transferred to normal working hours.
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Nielsen LP, Bjerke T, Christensen MB, Pedersen B, Rasmussen TR, Dahl R. Assessment of the allergic reaction in seasonal rhinitis: acoustic rhinometry is a sensitive and objective method. Clin Exp Allergy 1996; 26:1268-75. [PMID: 8955576] [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
BACKGROUND Seasonal allergic rhinitis constitutes an excellent in vivo model of an allergic mucosal inflammatory reaction. This offers the opportunity of studying the fundamentals of allergic inflammation in addition to improvement of knowledge on the basal pathophysiological mechanisms of the disease. So far, monitoring methods of disease activity and treatment efficacy have mainly been based upon subjective assessments, illustrating the impact of introducing reliable objective methods. OBJECTIVE To investigate the allergic inflammatory reaction of seasonal rhinitis through different objective methods and evaluate these as indicators of disease activity and treatment efficacy. METHODS Functional parameters, i.e. acoustic rhinometry and nasal metacholine challenge, and biological markers, i.e. blood eosinophil count, eosinophil cationic protein in serum (s-ECP) and nasal lavage fluid (n-ECP), were assessed before and at peak pollen season in 27 patients with grass pollen induced rhinitis. Patients were randomized to either nasal corticosteroid or placebo treatment and recorded nasal symptom scores. RESULTS Acoustic rhinometry revealed a significant difference in favour of steroid treatment (P < 0.05) comparing nasal volumes before and during season. This difference primarily relied upon a decrease in the placebo group (P = 0.05). A reduction from baseline of s-ECP in the steroid group (P < 0.01) was obtained. N-ECP demonstrated a difference between treatment groups, although not significant. Symptom scores increased in all patients during the pollen season, although this was only significant in the placebo treated patients (P < 0.01). The remaining methods applied did not demonstrate further differences, either within or between treatment groups. CONCLUSION Our results demonstrate acoustic rhinometry to be a sensitive and objective method of assessment of nasal obstruction. Furthermore, acoustic rhinometry and s-ECP reflect the impact of nasal steroid therapy on seasonal allergic rhinitis.
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Affiliation(s)
- L P Nielsen
- Department of Respiratory Diseases, University Hospital of Aarhus, Denmark
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Bødker A, Rasmussen TB, Christensen MB. The absorption of chlortetracycline following transscrotal instillation for the treatment of primary hydrocele testis. J Urol 1991; 145:792-4. [PMID: 2005703 DOI: 10.1016/s0022-5347(17)38453-7] [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] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We describe the absorption of chlortetracycline from the emptied hydrocele sac, which was instilled to treat a primary hydrocele of the testis. The study included 7 patients and 2 control subjects who were given 500 mg. chlortetracycline. Plasma concentration was determined at 0, 1/2, 1, 2, 4, 6, 12 and 24 hours after instillation, and in 2 patients plasma levels also were determined at 48 and 72 hours. The area under the plasma concentration-time curve (AUC1) was calculated in each case by using the trapezoidal rule. In the control group the plasma level was determined at 0, 1, 2, 4 and 6 hours after instillation. The area under the plasma concentration-time curve (AUC2) was calculated by the formula AUC2 = Co/Kc. The fraction F of absorption can be expressed as F = AUC1/AUC2; median F = 0.67 (range 0.41 to 0.92). We conclude that chlortetracycline passes readily and almost completely through the tunica vaginalis lining the hydrocele sac.
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Affiliation(s)
- A Bødker
- Department of Surgery, Holbaek Hospital, Copenhagen, Denmark
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Abstract
Serum from guinea pigs exposed to a single high dose of UVB and from controls was injected into the spleen of normal animals 5 days prior to sensitization. When 1.0 ml was transferred 4.5 h after irradiation, immunosuppression was obtained. Transfer of 1.5 ml of serum 2.5 h after irradiation failed to induce immunosuppression. This experimental model in guinea pigs might be valuable in further studies investigating the effect of other modalities of ultraviolet exposure (e.g., PUVA or high-dose UVA) on the release of soluble serum factor(s) inducing immunosuppression in allergic contact dermatitis.
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Abstract
Sodium cromoglycate was applied to the forearm of 9 subjects with known delayed hypersensitivity, and to the back of 14 dinitrochlorobenzene-sensitized guinea pigs before challenge with the allergen and sodium lauryl sulphate. Sodium cromoglycate did not decrease the intensity of allergic of toxic-irritant reactions in either humans or guinea pigs.
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Abstract
Flare-up reactions were induced in potassium dichromate hypersensitive guinea pigs by a single oral dose of 55 mg/kg. This dose is systemically toxic and higher than the dose required to induce the same reactions in humans. A total oral dose of potassium dichromate of 90-115 mg/kg induced immunological unresponsiveness for at least 6 weeks. With limitations, the guinea pig model may be helpful in screening the hyposensitization capacity of different haptens dosed orally.
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Abstract
22 DNCB sensitized guinea pigs were challenged with varying amounts dissolved in alcohol, acetone and olive oil. DNCB applied in alcohol resulted in almost 100% positive reactions; the test scores correlated to dose. When similar amounts were applied in alcohol and acetone, the former produced a significantly higher degree of positivity. The importance of defining allergen concentration, volume or weight of test substance applied and test area size, when comparing test results in guinea pigs and humans, is emphasized.
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Abstract
Sera from 100 subjects were tested for the presence of the cystic fibrosis (CF) "factor" utilizing the short circuit current rat jejunum bioassay. Comparing the mean percent decrease in short circuit current, the presumed normal group differs from the homozygous CF group at P = 0.001 and from the heterozygous group at P = 0.05. The two CF genotypes are statistically different at P = 0.004. There is, however, a large overlap among the three groups, which limits the assay's utility as a guide for factor purification as well as clinical use.
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Tucker RD, Hudrlik TR, Gibbs GE, Christensen MB. The effect of serum from patients with pancreatic disease on the short circuit current of rat jejunum. IEEE Trans Biomed Eng 1979; 26:607-13. [PMID: 511195 DOI: 10.1109/tbme.1979.326542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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