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Biomedical subjects

L Johnson

Publications and source records attributed to L Johnson.

At least 253 records · Page 14Linked to original sources
PubMed1992

Patterns of shoulder flexibility among college baseball players.

In this study, I investigated and analyzed the various joint motions in the shoulders of college baseball players. Twenty-six players (age=20.38+/-1.36 yr) from two colleges were examined for upper extremity range of motion (ROM), including shoulder flexion, extension, internal rotation at 90 degrees abduction, and external rotation at 90 degrees abduction. Joint motions were measured using a JAMAR(R), six-inch, double-arm goniometer. Pitchers demonstrated 22 degrees more shoulder flexion and 21 degrees more external rotation at 90 degrees abduction than infield position players, and 17 degrees more shoulder flexion than outfield position players. There was no significant difference between the dominant arm flexibility of infield and outfield position players. When comparing the dominant to nondominant arm relative to the position, infield position players demonstrated 5 degrees less shoulder flexion and 6 degrees more external rotation on the dominant side at 90 degrees abduction. Pitchers did not demonstrate any significant difference between the dominant and nondominant arm. There was, however, an indication that pitchers had a tendency to exhibit greater flexibility during flexion and external rotation at 90 degrees abduction in the dominant side than in the nondominant side.

Journal Article↗
PubMed1992

Peripheral blood mononuclear cell subsets in patients with severe inherited forms of epidermolysis bullosa.

BACKGROUND AND DESIGN: Epidermolysis bullosa (EB) is a group of inherited disorders in which slight trauma to the skin results in blister formation. Patients with severe types of EB suffer cutaneous infections that sometimes progress to septicemia and cutaneous and gastrointestinal carcinomas that are locally aggressive and frequently metastasize. Previous studies have shown deficits in natural killer (NK) cell activity as well as in lymphokine and monokine production in patients with severe forms of EB. Alterations in peripheral blood mononuclear cells, however, which may reflect on immune functions in patients with EB, have received little attention. A prospective study was designed to ascertain if differences existed between subsets of peripheral blood mononuclear cells in patients with severe forms of EB vs healthy control subjects. Thirty patients with clinical and histologic diagnoses of EB and 30 healthy volunteers were studied. Flow cytometric analysis of labeled cells was performed. RESULTS: Absolute numbers of CD3+, CD2+, CD4+, CD19+, NK+, CD29+, and CD45R+ cells were lower in patients with severe types of EB in comparison with controls. The T cells showed decreased numbers of interleukin 2 receptors. An increase in numbers of CD20+, CD4+ CD8+, and CD4-CD8- cells was also observed in patients with severe types of EB. CONCLUSION: Alterations in monocyte and lymphocyte subsets known to affect host immune response were observed in patients with severe forms of EB. Quantitative changes relative to controls included decreased total numbers of T cells with greater decreases in helper cells, decreased NK cells, and a diminished number of interleukin 2 receptors. Such changes have been associated previously with a lower resistance to infections and to neoplasia. The changes in subsets correlated with the severity of the cutaneous and extracutaneous disease in the patients with EB.

Antibodies, Monoclonal↗
PubMed1991

Comparative efficacy of three commercial feline leukemia virus vaccines against methylprednisolone acetate-augmented oronasal challenge exposure with virulent virus.

Three commercial FeLV vaccines, (A, B, and C) were purchased on the open market and administered to 8- to 20-week-old specific-pathogen-free kittens, according to manufacturers' instructions. A similar group of nonvaccinated kittens served as controls. All kittens were challenge-exposed oronasally with virulent FeLV 4 weeks after the final vaccination. Serum samples were monitored for FeLV-p27 antigenemia using an ELISA at 1- to 2-week intervals for at least 16 weeks after the last day of challenge exposure. Kittens that were either transiently (1 to 4 weeks) or never viremic during this period were counted as recovered, whereas kittens that became viremic and retained viremia for at least 10 weeks were counted as persistently viremic. The 3 vaccines were found to be 39% (vaccine C), 28% (vaccine B), and 17% (vaccine A) efficacious in preventing persistent viremia in immunized, compared with nonimmunized kittens.

Animals↗
PubMed1991

Measurements by microdialysis of free tissue concentrations of propranolol.

To determine the free concentration of a drug (propranolol) in the interstitial space in humans in vivo, seven male students were investigated by microdialysis of the periumbilical subcutaneous tissue. The microdialysis catheters were calibrated in vivo and the propranolol concentration was determined by high-performance liquid chromatography. Ten hours after intake of 80 mg of propranolol, the total plasma and free interstitial propranolol concentrations were 80 +/- 43 and 7 +/- 2 nM, respectively. After a second dose, maximum concentration was reached after 80 +/- 10 min and 98 +/- 12 min, in plasma, and the concentrations in the interstitial water were 594 +/- 138 and 27 +/- 7 nM, respectively. In a second study, microdialysis was performed on the left ventricular wall in six pigs receiving an intravenous injection of 5 mg of propranolol followed by a constant propranolol infusion for 40 min (5 mg propranolol per h). The maximum concentrations of propranolol were 97 +/- 29 and 6 +/- 2 nM in plasma and in interstitial water, respectively. The data suggest that microdialysis is a useful tool for recording the free concentrations of a drug in the interstitial space.

Adult↗
PubMed1991

Effect of photoperiod on the rate of 3H-thymidine incorporation of epididymal principal cells in adult Syrian hamsters.

Photoperiod-induced cycles of gonadal regression and recrudescence in the Syrian hamster were used to determine if epididymal growth in adults involves mitotic activity of principal cells. In Experiment 1, the following groups of adult hamsters were examined: induced recrudescing (5L:19D [5 hr light and 19 hr dark] for 13 wk followed by 14L:10D for at least 3 wk), spontaneous recrudescing (5L:19D for 25 wk), and active gonadal state (14:10D). In Experiment 2, adult hamsters were divided into the following groups: induced recrudescing, active, and regressed (5L:19D for 16 wk). Hamsters received subcutaneous injections of 0.5 microCi 3H-thymidine/g body weight three times/wk for 3 wk. The epididymis was fixed in a glutaraldehyde followed by osmium, embedded in Epon 812, and sectioned at 1 micron. Slides were dipped in Kodak NTB-3 emulsion, exposed for 2 or 3 months, developed, and evaluated for isotopic labeling of principal and basal cell nuclei by scoring 500 to 1,000 nuclei. In Experiment 1, the percentages of labeled principal cell nuclei for the induced recrudescing, spontaneous recrudescing, and active groups were 26 +/- 2%, 23 +/- 5%, and 9 +/- 1%, respectively. Considering the intermittent availability of 3H-thymidine during 21 days, this represents daily recruitment of 6.3%, 5.6%, and 2.2%, respectively. In Experiment 2, the percentages of labeled principal cell nuclei for induced recrudescing, active, and regressed groups were 12 +/- 4%, 3 +/- 1%, and 4 +/- 1%, respectively. There was no effect of photoperiod on labeling pattern of basal cells (1.5 +/- 0.6%, 1.2 +/- 0.1%, 0.4 +/- 0.1% for the three photoperiod groups, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Isolation of the mutagenic and DNA adduct-inducing components from a commercial preparation of HC blue 1 using Salmonella (TA98) bioassay-directed HPLC fractionation.

In the present study we report the separation of the mutagenic impurities from the nitrophenylenediamine hair dye HC Blue 1. This was accomplished by bioassay-directed HPLC fractionation, using Salmonella strain TA98 and reverse phase HPLC analysis. The mutagenic fraction eluted between 80 and 90% methanol, whereas the HPLC fraction containing the parent compound HC Blue 1 eluted with 30% methanol and was non-mutagenic. 100% of the mutagenic activity applied to the column was recovered in fractions that did not possess the blue color of HC Blue 1. Also, HPLC-purified HC Blue 1 did not form DNA adducts (32P-postlabeling) in Salmonella strain TA98. On the other hand, commercial HC Blue 1 and the mutagenic fraction derived from commercial HC Blue 1 (HPLC-isolated) gave similar DNA-adduct profiles that consisted of 7 adducts. DNA adduction was examined concomitantly with mutagenicity and toxicity studies on the HC Blue 1 samples in TA98. The data indicated that, in Salmonella, both the mutagenicity and DNA adduction of commercial HC Blue 1 are due to impurities and not the parent compound.

Autoradiography↗
PubMed1991

Revised clinical and laboratory criteria for subtypes of inherited epidermolysis bullosa. A consensus report by the Subcommittee on Diagnosis and Classification of the National Epidermolysis Bullosa Registry.

Inherited epidermolysis bullosa encompasses a number of diseases, with the common finding of blister formation after minor mechanical trauma to the skin. In some forms significant, if not eventually fatal, extracutaneous disease activity may occur. In recent years application of newer technologies has contributed substantially to an overall understanding of this collection of inherited diseases. Concurrently, many new phenotypes have been recognized, in part the result of ongoing prospective patient registries in the United States and abroad. Unfortunately, this has resulted in a massive literature that may appear to be confounded by seemingly excessive or arbitrary subdivision of epidermolysis bullosa variants. With these concerns in mind a subcommittee was established by the National Epidermolysis Bullosa Registry to summarize the current literature and to make recommendations as to the best clinical and laboratory criteria for the practical diagnosis and subclassification of patients with inherited epidermolysis bullosa.

Epidermolysis Bullosa↗
PubMed1991

An evaluation of an alternative to long-stay hospital care for frail elderly patients: I. The model of care.

Recent UK government policy has advocated the development of case management to provide more coordinated care at home for vulnerable people. This paper describes a service model whereby case managers, with devolved budgets, employed by the social services department, were located in a geriatric multidisciplinary team to provide an alternative for patients requiring long-stay hospital care. As well as co-ordinating packages of care, case managers were responsible for deploying the time of home care assistants, multi-purpose workers who assisted health care staff and undertook home help tasks. The role of case managers within the multidisciplinary team is explained and the tasks undertaken by home care assistants are identified. Home care assistants undertook a wider range of activities than either home helps or nurses, covering both personal and domestic care tasks.

Aftercare↗
PubMed1991

An evaluation of an alternative to long-stay hospital care for frail elderly patients: II. Costs and effectiveness.

This paper provides the main findings of an evaluation of a service to provide alternative care at home for patients receiving long-stay hospital care. Elderly people receiving the service were compared with a group of similar patients in an adjacent health district. The paper presents data on length of time at home and in hospital, changes in quality of life and care of elderly people, and effects upon informal carers for the two groups. Elderly people receiving community-based care had a higher quality of life, and there was no evidence of greater stress upon their carers. The community-based service, although it involved extra costs to the social services department, had lower costs for the health service and society as a whole than long-stay hospital provision. It is concluded that the model of care can effectively integrate the new approach of case management into an existing geriatric multidisciplinary team.

Activities of Daily Living↗
PubMed1991

Seasonal differences in equine spermatocytogenesis.

Spermatocytogenesis plays a pivotal role in regulation of spermatogenesis; however, its details remain relatively obscure in nonrodent species. The equine testis contains approximately 100% more spermatogonia in summer than in winter and appears to be a good model to identify the flexible components of spermatocytogenesis that cause seasonal changes in daily sperm production. Testes were taken from horses in the winter (n = 47) and in summer (n = 43). Tissues were fixed by glutaraldehyde-perfusion and submission in osmium, embedded in Epon or methacrylate, sectioned at 0.5 micron or 5 microns, stained with toluidine blue, and observed using bright-field microscopy. The combined total number of A1, A2, A3, and B1 (A plus B1) spermatogonia/testis and the numbers of B2 spermatogonia or early primary spermatocytes were determined by stereology of Epon sections involving testicular volume density and volume of spermatogonial nuclei. In a subset of horses, different spermatogonial subtypes (A1, A2, A3, and B1) were counted per 100 Sertoli cells in each of the 8 spermatogenic stages and expressed as percentage of all A plus B1 spermatogonia. The number of each spermatogonial subtype/testis for the large series of horses was calculated by multiplying the number of A plus B1 spermatogonia/testis (determined for each horse) by the percentage of that given spermatogonial subtype. Season did not significantly affect the number of any given subtype per 100 Sertoli cells in any stage or percentages of different subtypes of spermatogonia. Numbers of A1 (p less than 0.05), A2, A3, B1, or B2 spermatogonia (p less than 0.01) were greater in the breeding season.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Season but not age affects Sertoli cell number in adult stallions.

To evaluate the effect of age and season on Sertoli cell number per paired testes, ratio of germ cells per Sertoli cell, and daily sperm production, testes were obtained from 184 adult (4-20 yr) stallions at slaughter throughout one year. Numbers of Sertoli cells or germ cells were derived from nuclear volume density, volume of individual nuclei, and parenchymal volume. Germ cell to Sertoli cell ratios were calculated from cell numbers. Regression analysis was used to detect age-related differences in the breeding season (May-Jul) or throughout the year. A two-way analysis of variance was used to evaluate time periods (Nov-Jan, Feb-Apr, May-Jul, and Aug-Oct) and age groups (4-5.5, 6-12.5, or 13-20 yr). Paired parenchymal weight and daily sperm production per horse increased significantly with age. Neither regression nor analysis of variance revealed an effect of age on Sertoli cell number. While season contributed (p less than 0.01) to variation in Sertoli cell number per horse, there was no (p greater than 0.05) age x season interaction or age effect on Sertoli cell number. In testes obtained from adult stallions, age had no effect on the number of Sertoli cells per horse, the ratio of maturation-phase spermatids to Sertoli cells, or the ratio of all stage VIII germ cells to Sertoli cells. Given no age effect within a given season on Sertoli cell number per horse, the number of Sertoli cells in the recrudesced testis of the breeding season probably is not significantly different for a given stallion between 4 and 20 yr of age.

Aging↗
PubMed1991

Postinflammatory cataracts in the mouse: induction by human mycoplasma-like organisms.

Cataracts often occur in humans secondary to uveitis. Uveitis may be caused by various infectious agents, but rarely is the agent detected in the cataract. Mycoplasma-like organisms (MLO) were recently reported to cause human uveitis and retinitis. Cataracts were often present in those inflamed eyes. MLO are intracellular cell wall deficient pathogenic bacteria. They are pleomorphic tubulospherical and filamentous organisms with a characteristic ultrastructural appearance. No MLO culture system has been found despite 20 years of effort. The diagnosis of MLO disease rests on detection of the organisms in parasitised cells by a transmission electron microscope and response to antibiotics. In human intraocular inflammatory disease MLO are detectable in parasitised leucocytes and retinal pigment epithelial cells at the disease sites. Inoculation of MLO from a human source into mouse eyelids produced intraocular, chronic, progressive, inflammatory disease, with intraocular leucocytes parasitised by MLO in 15 of 100 mice versus 0 in 200 controls (p less than 0.05). This report describes the cataracts with MLO-parasitised intralenticular leucocytes in the inflamed eyes of 14 of those 15 mice versus 0 in 200 control mice (p less than 0.05). The results indicate that MLO penetrated the lens capsules to produce the cataracts, and they suggest that MLO could cause human cataracts. Alternative methods for detection of MLO and rifampin treatment of MLO intraocular disease are discussed.

Animals↗
PubMed1991

Human resource development in rural health care facilities.

In this paper, human resource development problems facing rural health care facilities are identified and it is recognised that, particularly in the face of escalating demands for training arising from environmental pressures such as implementation of the structural efficiency principle, a coordinated approach to meet these problems is desirable. Such coordination is often sought via a regional staff development service. Accordingly, using the organisational life cycle as a conceptual framework, staff development services in five NSW health regions are examined. Ranging from a cafeteria style to a results-orientation, a diversity of strategic approaches to staff development is reflected.

Geography↗
PubMed1991

Effect of age and season on the establishment of spermatogenesis in the horse.

To determine the age at which adult values for hormonal and testicular characteristics are established, testes and blood from 123 slaughtered horses, aged 1-5 years, were compared. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) and intratesticular testosterone (ITT) were determined by radio-immunoassay. Specimens were obtained in the non-breeding (n = 46) or breeding (n = 43) season in Experiment 1 (Exp. 1) and in the breeding (n = 34) season in Experiment 2 (Exp. 2). Testicular parenchyma was fixed in glutaraldehyde and homogenized to enumerate nuclei of Sertoli cells and elongated spermatids. Paired parenchymal weight (PPar-Wt), Sertoli cell number per horse (SC/H) and daily sperm production per gram of parenchyma (DSP/g) or per horse (DSP/H) were determined. In Exp. 1, DSP/g and SC/H were higher (P less than 0.05) in the breeding season. Left (LT-Wt; adult value established at 4 years) and right (RT-Wt; 3 years) testicular weights, PPar-Wt (4 years), DSP/g (3 years), DSP/H (3 years), SC/H (3 years), number of elongated spermatids/SC (ES/SC; 5 years), LH (5 years) and T (5 years) increased (P less than 0.01) with age. FSH also increased (P less than 0.05) with age. Age was correlated (r = 0.47 to 0.72; P less than 0.01) with LT-Wt, RT-Wt, PPar-WT, DSP/g, DSP/H, SC/H, ES/SC, LH and T. DSP/H was correlated (r = 0.40 to 0.94; P less than 0.01) with PPar-Wt, SC/H, ES/SC, LH and T. In Exp. 2, left testes were processed for histology and scored for percentage of tubules with elongated spermatids (% ES) or residual bodies (% RB). LT-Wt (adult value established at 4 years), RT-Wt (4 years), PPar-Wt (4 years), T (4 years), LH (4 years), % ES (2.5 years) and % RB (2.5 years) were influenced (P less than 0.01) by age. Age was correlated (r = 0.41 to 0.84; P less than 0.01) with PPar-Wt, % ES, % RB, LH, T and ITT. Although adult values of % ES, % RB, DSP/g and DSP/H were obtained by Year 3, PPar-Wt and serum hormonal concentrations increased significantly and DSP/H tended to increase to Year 4.

Age Factors↗
PubMed1991

Use of a computerized system for evaluation of equine spermatozoal motility.

Three ejaculates from each of 3 stallions were used to evaluate a computerized system (Hamilton-Thorn motility analyzer; HTMA) for measuring equine spermatozoal motility. Variance components (ejaculate-within-stallion, chamber-within-ejaculate, and microscopic field-within-chamber) were determined for each stallion after diluting ejaculates to 25 x 10(6) spermatozoa/ml with a skim milk-glucose seminal extender. The HTMA was compared with frame-by-frame playback videomicrography (VIDEO) for determining: percentage of spermatozoal motility and spermatozoal number in microscopic fields; curvilinear velocity and straight-line velocity of individual spermatozoa for 5 track types; and repeatability of those velocity measurements. The effect of spermatozoal number per microscopic field on incidence of intersecting spermatozoa and the outcome of intersecting spermatozoa also were evaluated. Greatest variability in motility measures was generally attributed to the microscopic field-within-chamber component. The HTMA was highly correlated with VIDEO for estimation of spermatozoal numbers per microscopic field (r = 0.99; P less than 0.001) and motility (r = 0.97; P less than 0.001); however over the entire range of spermatozoal numbers, the HTMA yielded higher spermatozoal numbers per microscopic field (P less than 0.05) and higher motility (P less than 0.05) than did VIDEO. The HTMA- and VIDEO-derived measurements of curvilinear and straight-line velocities were highly correlated for all spermatozoal track types, but both measures were higher (P less than 0.05) by use of the HTMA than by use of VIDEO for most track types. For 3 of 5 track types, measurements of curvilinear and straight-line velocities were less variable (P less than 0.05), using the HTMA, rather than VIDEO.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Sequential outpatient application of intravaginal prostaglandin E2 gel in the management of postdates pregnancies.

A randomized blinded investigation was undertaken to determine the efficacy and safety of sequentially applied intravaginal prostaglandin E2 (PGE2) gel for accelerating cervical ripening in an outpatient setting in low-risk prolonged pregnancies. Fifty women with uncomplicated pregnancies at or beyond 41 weeks' gestation and Bishop scores below 9 received twice-weekly outpatient administration of gel containing 2.0 mg of PGE2 or placebo. Thirty nulliparas and 20 multiparas were enrolled. The PGE2 gel failed to improve cervical ripening over placebo, as judged by Bishop scores. There was no difference between the groups in gestational age on admission to the labor and delivery suite, number of gel applications, requirement for oxytocin, incidence of cesarean delivery, or neonatal outcome. Only two patients (4%) experienced regular uterine contractions after gel insertion; these subsided spontaneously in both. None of the subjects experienced labor, tetanic contractions, evidence of fetal distress, or any other side effects related to gel insertion. We conclude that PGE2 gel in this dosage may be used safely in an outpatient setting, but more frequent application or earlier initiation may be required to produce a clinical effect.

Administration, Intravaginal↗