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Biomedical subjects

L W Johnson

Publications and source records attributed to L W Johnson.

At least 55 records · Page 3Linked to original sources
PubMed1995

Communal showers and the risk of plantar warts.

BACKGROUND: Plantar warts occur most commonly in adolescents and are more prevalent among users of public locker rooms. Previous studies have not differentiated shower rooms from locker rooms as risk factors. METHODS: The current study examined the prevalence of plantar warts among a group of 146 adolescents who used locker rooms. Subjects ranged in age from 10 to 18 years and were recruited from a public school and a swim club. All subjects used public locker rooms but only those in the swim club used communal showers on a regular basis. All subjects were interviewed by a physician and underwent an examination of the feet. RESULTS: There was a statistically significant difference in the prevalence of plantar warts between the shower room users (27%) and those who used only locker rooms (1.25%). CONCLUSIONS: The present study suggests that public shower users are at greater risk for plantar warts than are locker room users who do not use communal showers.

Adolescent↗
PubMed1994

Mycobacterium paratuberculosis infection in two llamas.

Mycobacterium paratuberculosis was diagnosed in 2 llamas by bacteriologic culturing and DNA probe testing of fecal and intestinal specimens. Diarrhea and weight loss were observed in both animals. Lesions in the gastrointestinal tracts of the 2 llamas were similar to pathologic changes reported in cattle infected with M paratuberculosis.

Animals↗
PubMed1994

Peripheral vascular complications of coronary angioplasty by the femoral and brachial techniques.

In order to monitor the incidence and types of peripheral vascular complications in a single institution, we prospectively entered 1,579 coronary angioplasty cases into a computer data base during the years 1991 and 1992. Various periprocedural risk factors were analyzed. The patients were followed closely to identify complications that occurred outside the laboratory or after discharge from the hospital. Peripheral vascular complications occurred in 37 patients (2.37%) and included hematoma 20 (1.27%), retroperitoneal bleeding 7 (.44%), false aneurysm 6 (.38%), occlusion 1 (.06%), infection 2 (.13%), and cholesterol emboli 1 (.06%). Risk factors for complications by multivariate analysis were older age, female gender, and clinical evidence of peripheral vascular disease. Other factors potentially related to vascular trauma or bleeding tendency that were not risk factors in this series were clinical presentation, use of heparin or thrombolytic agents, blood clotting parameters, and arterial sheath size. There was no significant difference between the femoral and brachial approaches in frequency of complications (2.5% vs. 1.6%), but femoral complications tended to carry greater morbidity.

Aged↗
PubMed1994

Update. Llama nutrition.

An understanding and appreciation of the New World Camelids' unique gastric anatomy and physiology, including rapid motility, prolonged digesta retention, rapid liquid passage rate, low protein maintenance requirements, low metabolized energy requirements, and low basal metabolism are imperative. Using this background, feeding recommendations for growing male llamas are proposed, and some suggestions are made concerning nutritional considerations of NWCs during the neonatal period, lactation, pregnancy, and work.

Animal Feed↗
PubMed1994

Llama herd health.

A herd health program that includes some firm recommendations based on research and medical and management observations made by the author is discussed. Some theoretical options are discussed that have been shared with the author by professional colleagues and llama owners.

Animal Husbandry↗
PubMed1994

Reproductive physiology of the male camelid.

The physiology of reproduction with emphasis on endocrinology of llamas and alpacas is addressed. Information regarding male anatomy, puberty, testicular function, semen description, and sexual behavior is also included.

Animals↗
PubMed1994

Congenital defects in the llama.

When faced with the question of what you should do as a veterinary practitioner, when presented with a congenital defect in a llama, one answer is to seek qualified help from your state veterinary diagnostic laboratory. But most importantly, encourage the owners of such animals to report the defect to their llama association, including pedigree information. The better we understand the pathogenesis of such defects, the better we will be able to control their incidence.

Animals↗
PubMed1994

Family physicians' perceptions of barriers to patients' dietary change.

A national random sample of 229 family physicians responded to a survey which included perceived barriers to patients' dietary change. Physicians perceived food taste preference (71%) as a deterrent to patients' dietary change followed by knowledge of what dietary changes to make (48%) and cost of food recommended (44%).

Attitude of Health Personnel↗
PubMed1994

Saving rural health care: strategies and solutions.

Health care for rural populations has been threatened in recent years by a significant number of hospital closures and a scarcity of primary care providers. While some factors that influence hospital closures lie beyond the reach of individual facilities, others, such as low occupancy rates and poor management, can and should be addressed through hospital networking, strategic planning, and well-focused marketing. To recruit and retain physicians, communities should develop financial-incentive packages and such alternatives to the traditional fee-for-service medical practice as recruiting older providers, establishing a community-based health maintenance organization, or founding a community-owned and -operated medical clinic staffed by primary care providers. Improving rural health care requires community involvement and commitment, and good planning.

Health Facility Closure↗
PubMed1993

Multivariable model for prediction of risk of significant complication during diagnostic cardiac catheterization. The Registry Committee of the Society for Cardiac Angiography & Interventions.

Although adequate data exist on the frequency of procedural-related complications during diagnostic cardiac catheterization, little information is available for the quantitative assessment of risk factors for significant complication. We analyzed 58,332 procedures in the 1990 SCA&I Registry Database in order to assess 1) the independent and cumulative significance of easily obtainable pre-procedural factors predictive of major complication and 2) the likelihood of a significant complication given the presence of these risk factors. A model was developed on a random sample of 38,888 patients and validated in the remaining 19,444 patients. Twelve variables were identified as having independent predictive behavior for significant complication with excellent agreement in the validation sample. The current model is an accurate and reliable instrument for stratifying risk of a significant complication during diagnostic catheterization.

Aged↗
PubMed1993

Effect of 5-lipoxygenase and cyclooxygenase blockade on porcine hemodynamics during continuous infusion of platelet-activating factor.

We hypothesized that 5-lipoxygenase and cyclooxygenase products might be mediators of cardiopulmonary and systemic vascular effects induced by a 4 h continuous infusion of platelet-activating factor (PAF, 10 ng/kg/min) in anesthetized pigs. Indomethacin (cyclooxygenase inhibitor) potentiated and CGS 8515 (5-lipoxygenase inhibitor) attenuated PAF-induced increases in total peripheral resistance (TPR) from 2.5 to 4 h. However, the 5-lipoxygenase inhibitor failed to modify pulmonary vasoconstriction and hypertension caused by PAF. Except for a delay in onset (approximately 44 s) and rate of development of pulmonary hypertension during the initial 10 min of PAF infusion, the pulmonary hemodynamic changes were also not attenuated by indomethacin. On the other hand, at 4 h, the PAF-induced pulmonary hypertension and systemic vasoconstriction were completely or partially reversed, respectively, by WEB 2086 (PAF receptor antagonist). The PAF-induced increases in plasma thromboxane B2 (TXB2) were blocked by indomethacin but not by CGS 8515, and at 4 h the 5-lipoxygenase inhibitor potentiated the levels of TXB2 in pigs treated with PAF. The plasma concentrations of 6-keto-PGF1 alpha and leukotriene B4 (LTB4) were not modified by PAF or CGS 8515 + PAF. We conclude that PAF-induced increases in TPR (2.5-4 h) are potentiated by indomethacin and are dependent on 5-lipoxygenase products other than LTB4. Although the early pulmonary vascular response (< 10 min) to PAF is dependent on cyclooxygenase products, the sustained response (after 10 min) cannot be explained by either 5-lipoxygenase or cyclooxygenase products but may be mediated directly by PAF receptors.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Comparative development of Eimeria tenella in primary chick kidney cell cultures derived from coccidia-resistant and -susceptible chickens.

A sixfold difference in resistance to coccidia (Eimeria tenella) infection between a resistant and a susceptible line of Auburn White Leghorn chickens, derived by selective breeding, has been reported. The purpose of the following study was to determine whether the resistance or susceptibility phenomenon in the Auburn lines could be manifested in a homogeneous group of isolated host kidney cells that support E. tenella development in vitro but not normally in vivo. Propagation of the parasite in host cells in vitro eliminates humoral and cellular elements of immunity, and allows the study of host genetic influences at the cellular level. Differences in parasite development were examined between the two lines of cells in vitro after 48 and 96 h of incubation; time periods that reflect initial infection of the host cells by the parasite and the subsequent asexual development. Quantification of differences by liquid scintillation counting was based on parasite-specific incorporation of pyrimidines, specifically [3H]-uracil. The results supported previous findings that overall E. tenella development was significantly greater in the host cells from the susceptible line than in the cells from the resistant cultures at both time periods.

Animals↗
PubMed1992

Percutaneous transluminal coronary angioplasty in New York State. Risk factors and outcomes.

OBJECTIVE: To identify significant independent risk factors for major percutaneous transluminal coronary angioplasty outcomes. DESIGN: Retrospective analysis using univariate and logistic regression analysis to identify significant independent risk factors for adverse outcomes. SETTING: All 31 hospitals performing percutaneous transluminal coronary angioplasty in New York State in 1991. PATIENTS: All 5827 patients undergoing percutaneous transluminal coronary angioplasty between January 1, 1991, and June 30, 1991, in New York State. MAIN OUTCOME MEASURES: In-hospital mortality, major complication(s) (in-hospital mortality, myocardial infarction, and/or emergency coronary artery bypass graft), and absence of angiographic success (stenosis reduction of less than 20% on any attempted lesion or residual stenosis of at least 50% on any attempted lesion). MAIN RESULTS: Before discharge from the hospital, a total of 37 patients (0.63%) died; 67 patients (1.1%) suffered a myocardial infarction, with a mortality rate of 4.5%; and 97 patients (1.7%) underwent emergency coronary artery bypass graft surgery, with a mortality rate of 2.1% (no deaths in 85 patients who were hemodynamically stable and two deaths among 12 patients who were hemodynamically unstable). A total of 187 patients (3.2%) experienced a major complication. Angiographic success was achieved for 88% of all patients. Multivariate analysis found four independent preprocedural variables related to death: female gender, hemodynamic instability, shock, and ejection fraction. CONCLUSIONS: Percutaneous transluminal coronary angioplasty outcomes in New York compare favorably with other recent results reported in the literature. Several preprocedural variables markedly increase the incidence of adverse events.

Aged↗
PubMed1992

Immunodeficiency syndrome associated with wasting and opportunistic infection in juvenile llamas: 12 cases (1988-1990).

Immunodeficiency was diagnosed as the cause of severe debilitating disease characterized by weight loss, failure to grow, and persistent infections that failed to respond to treatment in 12 young llamas. The llamas were affected after maternal-acquired immunity had decreased; failure of passive transfer of immunoglobulins thus was not suspected. Areas of lymph nodes containing T lymphocytes were hypocellular, suggesting T-cell involvement. High serum immunoglobulin concentrations were not found, despite the existence of infectious disease, suggesting at least secondary B-cell involvement. Results of lymphocyte blastogenesis assays were suggestive of B- and T-cell involvement. It was not possible to determine whether the condition was inherited or acquired.

Animals↗
PubMed1992

Review of radiation safety in the cardiac catheterization laboratory.

With the increasing use of coronary arteriography and interventional procedures, radiation exposure to patients and personnel working in cardiac catheterization laboratories has increased. Proper technique to minimize both patient and operator exposure is necessary. A practical approach to radiation safety in the cardiac catheterization laboratory is presented. This discussion should be useful to facilities with well-established radiation safety programs as well as facilities that require restructuring to cope with the radiation environment in a modern cardiac catheterization laboratory.

Cardiac Catheterization↗
PubMed1992

Differential effects of WEB 2086 and SRI 63-441 on TNF-alpha-induced alterations in cardiopulmonary function.

We hypothesized that platelet-activating factor (PAF) and cyclooxygenase products might be important mediators of the cardiopulmonary effects induced by tumor necrosis factor (TNF-alpha) in anesthetized pigs. A 6-h infusion of human recombinant TNF-alpha caused hypoxemia, leukopenia, thrombocytopenia, decreased cardiac index (CI), increased pulmonary vascular resistance (PVR) and increased mean pulmonary arterial (Ppa) and intratracheal (Pt) pressures. Administration of the PAF receptor antagonist SRI 63-441 or indomethacin blocked the early (0.25-0.5 h) and attenuated the later increases in PVR and Ppa; indomethacin also attenuated the increase in Pt and hypoxemia associated with TNF-alpha infusion. WEB 2086 did not attenuate the TNF-alpha-induced alterations in CI, PVR, Pt, or PaO2. The in vivo specificity of SRI 63-441 and WEB 2086 was tested by infusing exogenous PAF, prostaglandin (PG) F2 alpha, U-46619 [thromboxane (Tx)A2 receptor mimetic], or arachidonic acid (AA) before and during administration of SRI 63-441 or WEB 2086. Both antagonists blocked the cardiopulmonary effects induced by exogenous PAF. SRI 63-441, but not WEB 2086, significantly attenuated the increased PVR caused by PGF2 alpha, U-46619, and AA. We conclude that SRI 63-441 is a less specific PAF receptor antagonist in vivo compared with WEB 2086 and that cyclooxygenase products, but not PAF, contribute significantly to the cardiopulmonary responses induced by exogenously infused TNF-alpha in pigs.

Animals↗
PubMed1992

Hematologic features of iron deficiency anemia in llamas.

Iron deficiency anemia was identified and characterized in three 14 to 29-month-old male llamas (llama Nos. 1-3) from separate herds in Colorado. The identification of iron deficiency anemia was based on hypoferremia (serum iron = 20-60 micrograms/dl), erythrocytic features, and hematologic response to iron therapy. The anemia was moderate and nonregenerative and characterized by erythrocyte hypochromia, microcytosis (mean cell volume = 15-18 fl), and decreased mean corpuscular hemoglobin concentration (36.0-41.0 g/dl). Morphologic features unique to llamas with iron deficiency anemia included irregular distribution of hypochromia within erythrocytes and increased folded cells and dacryocytes. The cause of iron deficiency was not determined. The llamas were treated with various doses and schedules of parenteral iron dextran. Two of the llamas were monitored for up to 14 months after the start of iron therapy and experienced increases in hematocrit and mean cell volume values. In one llama, progressive replacement of microcytic cells with normal cells was visualized on sequential erythrocyte volume distribution histograms following iron therapy.

Anemia, Hypochromic↗