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Holterman AX, Rogers K, Edelmann K, Koelle DM, Corey L, Wilson CB. An important role for major histocompatibility complex class I-restricted T cells, and a limited role for gamma interferon, in protection of mice against lethal herpes simplex virus infection. J Virol 1999; 73:2058-63. [PMID: 9971787 PMCID: PMC104449 DOI: 10.1128/jvi.73.3.2058-2063.1999] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Herpes simplex virus (HSV) inhibits major histocompatibility complex (MHC) class I expression in infected cells and does so much more efficiently in human cells than in murine cells. Given this difference, if MHC class I-restricted T cells do not play an important role in protection of mice from HSV, an important role for these cells in humans would be unlikely. However, the contribution of MHC class I-restricted T cells to the control of HSV infection in mice remains unclear. Further, the mechanisms by which these cells may act to control infection, particularly in the nervous system, are not well understood, though a role for gamma interferon (IFN-gamma) has been proposed. To address the roles of MHC class I and of IFN-gamma, C57BL/6 mice deficient in MHC class I expression (beta2 microglobulin knockout [beta2KO] mice), in IFN-gamma expression (IFN-gammaKO mice), or in both (IFN-gammaKO/beta2KO mice) were infected with HSV by footpad inoculation. beta2KO mice were markedly compromised in their ability to control infection, as indicated by increased lethality and higher concentrations of virus in the feet and spinal ganglia. In contrast, IFN-gamma appeared to play at most a limited role in viral clearance. The results suggest that MHC class I-restricted T cells play an important role in protection of mice against neuroinvasive HSV infection and do so largely by mechanisms other than the production of IFN-gamma.
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Torg JS, Harris SM, Rogers K, Stilwell GJ. Retrospective report on the effectiveness of a polyurethane football helmet cover on the repeated occurrence of cerebral concussions. AMERICAN JOURNAL OF ORTHOPEDICS (BELLE MEAD, N.J.) 1999; 28:128-32. [PMID: 10067717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
This report reviews the literature and unpublished data and presents survey results related to the use of a polyurethane football helmet cover. Two hundred forty-five individuals, identified by the helmet manufacturer as having purchased at least one device, were sent a survey after the 1992, 1993, and 1994 football seasons; 155 (63.3%) of the surveys were returned. The questionnaire, designed to be completed by the athlete, required a detailed history of concussions occurring both prior to and during the period the device was used. Individuals used the device as a result of having incurred at least one concussion. Rates of concussion reoccurrence while the device was worn were grouped by the number of previous concussions (1, 2, 3, or 4+) that occurred over a 4year period prior to use of the device. The rate of concussion reoccurrence was 2.4%, 7.3%, 15.8%, and 33.3%, respectively, over a 4-year period. The range appeared to reflect a parallel relationship between pre- and post-device concussion experiences: the more concussions experienced prior to adopting the device, the higher the rate of concussion reoccurrence while using the device. The natural history of repeated occurrences of concussive events may not be affected by the use of a polyurethane football helmet cover. We suggest that such a device not be routinely used prophylactically, but instead be reserved for individuals with 1 to 2 prior concussion injuries. However, at this time, we neither recommend nor discommend the device.
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Pecht M, Hillman C, Rogers K, Jennings D. Conductive filament formation: a potential reliability issue in laminated printed circuit cards with hollow fibers. ACTA ACUST UNITED AC 1999. [DOI: 10.1109/6104.755092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Manacci C, Rogers K, Martin G, Kovach B, Mancuso C, Fallon W. Efficacy of 24-hour shifts: prepared or impaired? A prospective study. Air Med J 1999; 18:20-5. [PMID: 10345781 DOI: 10.1016/s1067-991x(99)90005-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The effect of duty duration on performances is unknown. In a prospective cohort study model using repeated measures, we evaluated the effect of shift length on a battery of neuropsychologic performance indicators using our flight program as the test site. METHODS Flight nurses completing 24- and 12-hour shifts were tested on memory, attention, reasoning, motor, and speed measures. Ratings of stress, fatigue, sleep quality, and logged amount of work and sleep were evaluated from personal journals kept for this purpose. Data were analyzed by linear regression and repeated measures multivariate analysis of variance (MANOVA) and analysis of variance (ANOVA). Clinical significance was set at P < 0.05. RESULTS Fifteen subjects completed the testing and evaluation process. Neuropsychologic testing demonstrated that performance was not predicted by shift length, time of shift (day versus night), amount or quality of sleep before or during shift, or fatigue ratings. Age, gender, and education did not mediate shift length/test performance relationships. Uninterrupted sleep, stress ratings, and number of flights per shift modestly reduced some test scores. Predictably, repeated testings resulted in practice effects that reduced analysis power. We found that 24-hour shifts per se do not result in a cognitive decline compared with 12-hour shifts. Inconsistent sleep, number of flights, and the stressfulness of flights may have greater impact.
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Mealey KL, Barhoumi R, Rogers K, Kochevar DT. Doxorubicin induced expression of P-glycoprotein in a canine osteosarcoma cell line. Cancer Lett 1998; 126:187-92. [PMID: 9585065 DOI: 10.1016/s0304-3835(98)00004-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Canine and human osteosarcoma are very similar with respect to clinical presentation, radiological and histopathological features, metastatic rate and pattern and response to therapy. For these reasons, canine osteosarcoma is a useful intermediate model for the disease in humans. Overexpression of P-glycoprotein, the product of the MDR1 gene, is the most important predictor of an adverse clinical course in human patients with osteosarcoma. Exposure of canine osteosarcoma cells to doxorubicin resulted in overexpression of MDR1 mRNA and P-glycoprotein. Furthermore, these cells failed to accumulate doxorubicin intracellularly and were less sensitive to vincristine-induced cytotoxicity as compared to parental cells.
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Chattopadhyay N, Cheng I, Rogers K, Riccardi D, Hall A, Diaz R, Hebert SC, Soybel DI, Brown EM. Identification and localization of extracellular Ca(2+)-sensing receptor in rat intestine. Am J Physiol Gastrointest Liver Physiol 1998; 274:G122-30. [PMID: 9458781 DOI: 10.1152/ajpgi.1998.274.1.g122] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The extracellular calcium (Ca2+o)-sensing receptor (CaR) plays vital roles in Ca2+o homeostasis, but no data are available on its expression in small and large intestine. Polymerase chain reaction products amplified from reverse-transcribed duodenal RNA using CaR-specific primers showed > 99% homology with the rat kidney CaR. Northern analysis with a CaR-specific cRNA probe demonstrated 4.1- and 7.5-kb transcripts in all intestinal segments. Immunohistochemistry with CaR-specific antisera showed clear basal staining of epithelial cells of small intestinal villi and crypts and modest apical staining of the former, whereas there was both basal and apical staining of colonic crypt epithelial cells. In situ hybridization and immunohistochemistry also demonstrated CaR expression in Auerbach's myenteric plexus of small and large intestines and in the submucosa in the region of Meissner's plexus. Our results reveal CaR expression in several cell types of small and large intestine, in which it may modulate absorptive and/or secretomotor functions.
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Abstract
Plexosarcomas are rare soft tissue sarcomas, previously reported in association with gastrointestinal autonomic nerve (GAN) plexi. We report the first case arising from the autonomic nerve plexus of the bladder.
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Wang J, Lu F, Kane SA, Choi YK, Smyth MR, Rogers K. Hydrocarbon pasting liquids for improved tyrosinase-based carbon-paste phenol biosensors. ELECTROANAL 1997. [DOI: 10.1002/elan.1140091413] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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110
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Rogers K, Barrington GM, Parish SM. Squamous cell carcinoma originating from a cutaneous scar in a llama. THE CANADIAN VETERINARY JOURNAL = LA REVUE VETERINAIRE CANADIENNE 1997; 38:643-4. [PMID: 9332750 PMCID: PMC1576865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A nonhealing wound associated with a laceration in a 12-year-old llama was evaluated. Initial attempts at closure were unsuccessful and biopsy revealed scar tissue. Subsequent biopsies, 18 mo later, revealed squamous cell carcinoma with regional metastasis. This report describes squamous cell carcinoma, secondary to a traumatic wound in a llama.
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Skinner PP, Ogunbiyi OA, Scholefield JH, Start RD, Smith JH, Sharp F, Rogers K. Skin appendage involvement in anal intraepithelial neoplasia. Br J Surg 1997; 84:675-8. [PMID: 9171763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND High-grade anal intraepithelial neoplasia (AIN III) may be premalignant. Surgical excision of large areas of anal epithelium carries significant morbidity. Ablation treatments may carry less morbidity; however, the depth of ablation is uncertain and failure to ablate dysplasia in hair shafts and other skin appendages may lead to early recurrence. METHODS This study assesses morphometric aspects of skin appendages in perianal skin and anal canal mucosa in tissues from 30 patients with AIN III. Both normal and dysplastic epithelium was assessed in each patient. The depth to which AIN III involved skin appendages was measured using computerized image analysis. RESULTS Both the perianal epidermis and anal canal mucosa affected by AIN III were significantly thicker than normal. Nineteen of 30 patients with AIN III had skin appendage involvement. Some 57 per cent of hair follicles (79 of 138), 16 per cent of sebaceous glands (11 of 69) and 25 per cent of sweat glands (24 of 96) observed beneath an abnormal epithelium had evidence of AIN. The median depth of AIN involvement of the hair follicle was 1.14 (range 0.44-1.67) mm, sebaceous glands 1.44 (range 0.96-1.90) mm, and sweat glands 0.94 (range 0.50-2.20) mm. These figures do not take into account tissue shrinkage due to histological processing. CONCLUSION AIN III involvement of epithelial appendages is a significant problem. For disease eradication, tissue destruction or removal to a depth of at least 2.2 mm below the adjacent basement membrane is required. Surgical excision of high-grade AIN remains the treatment of choice.
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Skinner PP, Ogunbiyi OA, Scholefield JH, Start RD, Smith JHF, Sharp F, Rogers K. Skin appendage involvement in anal intraepithelial neoplasia. Br J Surg 1997. [DOI: 10.1002/bjs.1800840528] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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113
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Ye C, Ho-Pao CL, Kanazirska M, Quinn S, Rogers K, Seidman CE, Seidman JG, Brown EM, Vassilev PM. Amyloid-beta proteins activate Ca(2+)-permeable channels through calcium-sensing receptors. J Neurosci Res 1997; 47:547-54. [PMID: 9067864 DOI: 10.1002/(sici)1097-4547(19970301)47:5<547::aid-jnr10>3.0.co;2-v] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The amyloid-beta peptides (A beta) are produced in excess in Alzheimer's disease (AD) and may contribute to neuronal dysfunction and degeneration. This study provides strong evidence for a novel cellular target for the actions of A beta, the phospholipase C-coupled, extracellular Ca(2+)-sensing receptor (CaR). We demonstrate that A beta(s) produce a CaR-mediated activation of a Ca(2+)-permeable, nonselective cation channel (NCC), probably via elevation in cytosolic Ca2+ (Cai), in cultured hippocampal pyramidal neurons from normal rats and from wild type mice but not those from mice with targeted disruption of the CaR gene (CaR -/-). A beta(s) also activate NCC in CaR-transfected but not in nontransfected human embryonic kidney (HEK293) cells. Thus aggregates of A beta deposited on hippocampal neurons in AD could appropriately activate the CaR, stimulating Ca(2+)-permeable channels and causing sustained elevation of Cai with resultant neuronal dysfunction.
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Mosnik DM, Spring B, Rogers K, Baruah S. Tardive dyskinesia exacerbated after ingestion of phenylalanine by schizophrenic patients. Neuropsychopharmacology 1997; 16:136-46. [PMID: 9015796 DOI: 10.1016/s0893-133x(96)00054-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Despite continued research, the influences that promote or exacerbate tardive dyskinesia (TD) symptoms remain incompletely understood. Recent findings (Gardos et al. 1992; Richardson et al. 1989) suggest that ingestion of the dietary constituent, phenylalanine, might exacerbate TD symptoms, but a double-blind, placebo-controlled challenge had not previously been conducted in schizophrenic patients. On two different mornings, in counterbalanced order, 18 male schizophrenic patients with TD were challenged with either 100 mg/kg phenylalanine or placebo. Effects on abnormal involuntary movements, recall memory, and plasma phenylalanine were measured 90 minutes post-challenge. The results supported the hypothesis in that involuntary movements increased to a statistically and clinically meaningful degree after the phenylalanine challenge, but not after placebo. No effects on memory were detected. Significant order effects characterized the plasma findings but not the behavioral data. Results indicate that a dietary constituent, the amino acid phenylalanine, can potentially exacerbate tardive dyskinesia symptoms in schizophrenic patients. The influence of phenylalanine and other ingested substances on clinical symptomatology warrants further investigation.
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Boyle M, Sitler M, Kimura I, Rogers K, Duffy AJ. Knowledge and Attitudes of Certified Athletic Trainers in Pennsylvania Toward HIV/AIDS and Treating HIV-Positive Athletes. J Athl Train 1997; 32:40-4. [PMID: 16558431 PMCID: PMC1319234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
OBJECTIVE As the number of people infected with the Human Immunodeficiency Virus (HIV) continues to increase so does the likelihood that athletic trainers will treat HIV-positive athletes. The purposes of this study were to determine how knowledgeable certified athletic trainers in Pennsylvania are about HIV/ AIDS and their attitudes toward treating the injuries of HIV- positive/AIDS athletes. Another purpose of this study was to determine what effect the athletic trainers' HIV/AIDS attitudes had on their HIV/AIDS knowledge level. DESIGN AND SETTING A questionnaire was mailed to 807 NATA-certified athletic trainers who resided in the state of Pennsylvania. A total of 410 (50.8%) athletic trainers participated in the study: 241 (58.8%) males and 169 (41.2%) females. SUBJECTS NATA-certified athletic trainers who resided in the state of Pennsylvania as of March 19, 1994. MEASUREMENTS A questionnaire was developed by the investigators after reviewing the appropriate literature and in consultation with a panel of experts that consisted of athletic trainers, physicians, and a health educator who specialized in HIV/AIDS education. The questionnaire consisted of three sections: demographic information, HIV/AIDS knowledge, and HIV/AIDS attitude. Returned questionnaires were analyzed via descriptive (frequencies, percentages, and means) and inferential statistics. Univariate analysis consisted of independent t tests to determine what effect the athletic trainers' HIV/AIDS attitudes had on their HIV/AIDS knowledge level. RESULTS NATA-certified athletic trainers in Pennsylvania are moderately knowledgeable about HIV/AIDS and have constructive attitudes in treating the athletic injuries of HIV-positive/ AIDS athletes. Their major concern, however, is fear of HIV transmission. It was further determined that differences in HIV/AIDS attitudes had no effect on HIV/ AIDS knowledge level. CONCLUSIONS The likelihood that athletic trainers will treat HIV-positive athletes is ever increasing. HIV/AIDS education and appropriate clinical precautions are paramount in protecting the clinician and athlete alike.
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Kirstein F, Garcia B, Zhong R, Rogers K, Ohene-Fianko D, Hashimoto T, Grant D. Characterization of villi appearing in segmental colon transplants. Transplant Proc 1996; 28:2462. [PMID: 8907902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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117
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Hadley S, Chang M, Rogers K. Effect of syringe size on bruising following subcutaneous heparin injection. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1075-4210(96)80077-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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118
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Ye C, Rogers K, Bai M, Quinn SJ, Brown EM, Vassilev PM. Agonists of the Ca(2+)-sensing receptor (CaR) activate nonselective cation channels in HEK293 cells stably transfected with the human CaR. Biochem Biophys Res Commun 1996; 226:572-9. [PMID: 8806675 DOI: 10.1006/bbrc.1996.1396] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Calcium (Ca2+) ions serve multiple roles both intra- and extracellularly. We recently cloned a cell surface, Cao(2+)-sensing receptor (CaR) that plays a central role in Cao2+ homeostasis by enabling direct regulation by Cao2+ of parathyroid hormone (PTH) secretion and the function of other tissues involved in mineral ion homeostasis. In parathyroid cells, the CaR activates phospholipase C, thereby raising the levels of inositol trisphosphate (IP3) and releasing Ca2+ from intracellular stores. High Cao2+ also activates Ca2+ influx into parathyroid cells through poorly defined mechanisms that may involve Ca(2+)-permeable, nonselective cation channels (NCC). We now show that human embryonic kidney (HEK293) cells also have NCC and, furthermore, that these channels are regulated by the CaR. We have utilized the cell-attached configuration of the patch clamp technique to characterize the properties of these channels as well as their regulation by various CaR agonists added to the external bath solution. The polycationic CaR agonist, neomycin (100 microM), as well as an elevated concentration of Cao2+ (3 mM), both of which activate the cloned CaR, significantly increased the probability of channel opening (Po) in HEK cells stably transfected with the CaR but not in nontransfected HEK cells which do not contain the receptor. Thus, the activation of the CaR enhances the activity of Ca(2+)-permeable NCC in these cells, which could contribute to the sustained increase in Cai2+ in parathyroid cells which is observed in response to elevated Cao2+. The CaR may also regulate the membrane functions of other CaR-expressing cells (e.g., those in the brain), at least in part, by modulating similar channels.
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Jennings M, Sweetland H, Smith C, Wolf C, Lennard M, Tucker G, Woods H, Rogers K. Lack of relationships between the debrisoquine (CYP2D6) and mephenytion (CYP2C19) oxidation polymorphisms and susceptibility to breast cancer. Breast 1996. [DOI: 10.1016/s0960-9776(96)90020-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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120
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Hadley SA, Chang M, Rogers K. Effect of syringe size on bruising following subcutaneous heparin injection. Am J Crit Care 1996. [DOI: 10.4037/ajcc1996.5.4.271] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND: Bruising and induration associated with subcutaneous heparin injection often result in sustained tenderness and severe ecchymosis at the injection site. Research-based practice guidelines for subcutaneous heparin administration are needed to reduce these adverse effects. OBJECTIVES: The purpose of this study was to investigate the effect of syringe size (1-mL vs 3-mL) on postinjection-site bruising and induration following the administration of subcutaneous heparin. METHODS: A convenience sample of 29 subjects receiving 5000 units of subcutaneous heparin at least twice a day was recruited from a large urban hospital. Subjects received their regularly scheduled subcutaneous heparin injections with a 3-mL or a 1-mL syringe in a randomized sequence using a standardized procedure. Injection sites were assessed for bruises and induration at 24, 48, and 72 hours after injection. RESULTS: The incidence of injection site bruising with 1- and 3-mL syringes was 79% and 69%, respectively. The use of a 3-mL vs 1-mL syringe resulted in significantly smaller bruises at 48 and 72 hours after injection. Induration at the injection site occurred in three patients. CONCLUSIONS: Findings suggest that 3-mL syringes are preferable to 1-mL syringes for heparin administration. The effect of other injection-related variables should be studied with the use of the 3-mL syringe, and tested on various populations.
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121
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Hadley SA, Chang M, Rogers K. Effect of syringe size on bruising following subcutaneous heparin injection. Am J Crit Care 1996; 5:271-6. [PMID: 8811149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Bruising and induration associated with subcutaneous heparin injection often result in sustained tenderness and severe ecchymosis at the injection site. Research-based practice guidelines for subcutaneous heparin administration are needed to reduce these adverse effects. OBJECTIVES The purpose of this study was to investigate the effect of syringe size (1-mL vs 3-mL) on postinjection-site bruising and induration following the administration of subcutaneous heparin. METHODS A convenience sample of 29 subjects receiving 5000 units of subcutaneous heparin at least twice a day was recruited from a large urban hospital. Subjects received their regularly scheduled subcutaneous heparin injections with a 3-mL or a 1-mL syringe in a randomized sequence using a standardized procedure. Injection sites were assessed for bruises and induration at 24, 48, and 72 hours after injection. RESULTS The incidence of injection site bruising with 1- and 3-mL syringes was 79% and 69%, respectively. The use of a 3-mL vs 1-mL syringe resulted in significantly smaller bruises at 48 and 72 hours after injection. Induration at the injection site occurred in three patients. CONCLUSIONS Findings suggest that 3-mL syringes are preferable to 1-mL syringes for heparin administration. The effect of other injection-related variables should be studied with the use of the 3-mL syringe, and tested on various populations.
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Sever S, Rogers K, Rogers MJ, Carter C, Söll D. Escherichia coli tryptophanyl-tRNA synthetase mutants selected for tryptophan auxotrophy implicate the dimer interface in optimizing amino acid binding. Biochemistry 1996; 35:32-40. [PMID: 8555191 DOI: 10.1021/bi952103d] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Tryptophan auxotrophs of Escherichia coli in which mutations were mapped to the trpS locus (encoding tryptophanyl-tRNA synthetase) have been previously isolated. We have investigated the tryptophanyl-tRNA synthetase (TrpRS) purified from six auxotrophic strains for changes in amino acid activation and aminoacylation. Steady-state kinetic analyses show that these mutant TrpRS proteins have increases in the apparent KM for tryptophan, decreases in turnover number, or both, without significant changes in the apparent KM for ATP or tRNA(Trp). The crystal structure of a highly homologous tryptophanyl-tRNA synthetase from Bacillus stearothermophilus in a complex with the cognate aminoacyl adenylate allowed us to place the mutations in a structural context. The mutations in the enzymes are located in the KMSKS loop (M196I), in or near the active site (D112E, P129S, A133E) or far from the active site. The last three mutants (T60R, L91F, G329S) could not be predicted by examination of the protein structure as they line an interface between the C-terminal alpha-helix of one subunit and the Rossmann folds of both subunits, thus affecting a specific region of the dimer interface. These results support a role for dimerization in properly configuring the two active sites of the dimeric enzymes in the Trp/Tyr subclass of class I aminoacyl-tRNA synthetases in order to achieve optimal catalysis.
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Torg JS, Stilwell G, Rogers K. The effect of ambient temperature on the shoe-surface interface release coefficient. Am J Sports Med 1996; 24:79-82. [PMID: 8638758 DOI: 10.1177/036354659602400114] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Previous studies of the shoe-surface interface correlated foot fixation with cleat length, configuration, and material composition as well as turf type and surface conditions. Our study examined the effect of temperature on the rotational torsion resistance of artificial turf football shoes. Five football shoe models, a flat-soled basketball-style turf shoe, a natural grass soccer-style shoe, and three multistudded turf shoes, were studied on dry Astro Turf at five temperatures (range, 52 degrees F to 110 degrees F). An assay device, a prosthetic foot mounted on a loaded stainless steel shaft, was used to determine the force necessary to release a shoe from the turf's surface. We used a torque wrench to apply a rotational force so that each shoe was pivoted counterclockwise through an arc of 60 degrees. Our results indicated that release coefficients differ within and among the shoe models at various turf temperatures. We also found that an increase in turf temperature, in combination with cleat characteristics, affects shoe-surface interface friction and potentially places the athlete's knee and ankle at risk of injury. Based on an established risk criterion, which correlated shoe-surface interface combinations in the laboratory with documented clinical occurrences, only the flat-soled basketball-style turf shoe could be designated "safe" or "probably safe" at all five temperatures.
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Abstract
BACKGROUND AND OBJECTIVES Pyropheophorbide-a-hexyl ether (HPPH) is a new compound being investigated for use as a photosensitizer for photodynamic therapy; however, the pharmacokinetics are not known for any of the target species likely to be treated with this drug. The objective of this study was to determine the pharmacokinetic parameters of this drug prior to institution of a clinical trial in canine patients with various cancers. STUDY DESIGN, MATERIALS AND METHODS HPPH (0.3mg/kg i.v.) was administered to 12 dogs and blood samples were drawn at intervals for 24 hours and plasma HPPH concentrations were determined. Pharmacokinetic parameters were calculated for each dog. RESULTS No evidence of toxicity was noted in any dog. The mean half-life was calculated to be 26.98 +/- 2.35 hrs. The mean clearance was 5.061 +/- 0.214 ml/hr/kg. The mean volume of distribution of the central compartment was 0.069 +/- 0.003 L/kg, and the mean steady state volume of distribution was 4.47 +/- 0.25 L/kg. CONCLUSION The conclusion is that 0.3 mg/kg HPPH injected intravenously resulted in measurable plasma levels for 24 hrs, and resulted in no detectable adverse reactions.
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Lewis MA, Leake B, Giovannoni J, Rogers K, Monahan G. Drugs, poverty, pregnancy, and foster care in Los Angeles, California, 1989 to 1991. West J Med 1995; 163:435-40. [PMID: 8533405 PMCID: PMC1303166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To determine the characteristics and childbearing histories of women whose infants entered foster care in Los Angeles County, we examined the cases of 1,155 drug-using women whose infants were removed from them at birth and 236 non-drug-using women whose infants were also removed at birth by court order (July 1989 through March 1991). All of the women were indigent, and less than half had graduated from high school. The drug-using women frequently had criminal records, and more than a quarter were homeless. Many comparison women had mental health problems, and some (16.7%) were teenagers under court custody. Overall, 80% of all the children born to both groups of women were under court jurisdiction. Data obtained after study infants' births on 926 drug-using women observed for 18 months revealed that 22% had borne another infant who was placed in foster care; half of these infants had a positive drug immunoassay. Of the 185 non-drug-using women with 18-month follow-ups, 7.6% had borne another child who was in foster care. The magnitude of the repeated childbearing recorded among both groups of women in this study shows that preventive programs including family planning, mental health services, and drug prevention or rehabilitation programs have not reached this population.
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