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Biomedical subjects

A J Nelson

Publications and source records attributed to A J Nelson.

At least 19 recordsLinked to original sources
PubMed1992

Characterization and cloning of a novel glycoprotein expressed by stromal cells in T-dependent areas of peripheral lymphoid tissues.

A novel glycoprotein (gp) expressed by stromal cells of peripheral lymphoid tissue has been characterized immunohistochemically, biochemically, and at the molecular level. This molecule, gp38, was identified with a monoclonal antibody (mAb) (clone 8.1.1) previously shown to react with a subpopulation of thymic epithelium. This mAb generated a reticular labeling pattern in medullary and paracortical areas of lymph nodes and in splenic white pulp. At the ultrastructural level, labeling by the 8.1.1 mAb was restricted to fibroblastic reticular stromal cells. Serial sections of lymph node and spleen labeled with anti-CD3, anti-B220, and 8.1.1 mAbs clearly showed that the 8.1.1+ cells were associated with T cell-dependent areas. In severe combined immunodeficiency (SCID) or Nu/Nu mice, splenic white pulp also exhibited reticular labeling with the 8.1.1 mAb in the absence of detectable numbers of T cells, indicating that the appearance of 8.1.1-reactive stromal cells in discrete areas of peripheral lymphoid tissue was T cell independent. The cDNA encoding this stromal cell molecule was cloned by direct expression in COS cells and found to encode a 172 amino acid sequence with the typical features of a type I integral membrane protein. COS cells transfected with the gp38 clone direct the expression of an approximately 38-kD protein that reacts with the 8.1.1 mAb but not with isotype-matched controls. Comparison of the predicted amino acid sequence of 8.1.1 mAb but not with isotype-matched controls. Comparison of the predicted amino acid sequence of 8.1.1 with proteins in the National Biomedical Research Foundation (NBRF) data base showed that gp38 is very closely related to the early response protein OTS-8 obtained from a cDNA library of tumor promoting agent (TPA)-induced murine osteoblastic cell line, MC3T3-E1.

Amino Acid Sequence↗
PubMed1989

The key role of records in a production medicine practice.

The needs of dairy farmers for veterinary assistance have changed and are still changing. It appears that many future opportunities in dairy practice will involve active consultation on herd management factors. The ability to evaluate herd records will be crucial to this effort. This article discusses organizing and then utilizing a production medicine program based on systematic records analysis.

Animals↗
PubMed1988

Hyperthermia.

Explore the source record for details and available documents.

Humans↗
PubMed1988

Antihypertensive thiadiazoles. 1. Synthesis of some 2-aryl-5-hydrazino-1,3,4-thiadiazoles with vasodilator activity.

Some 2-aryl-5-hydrazino-1,3,4-thiadiazoles have been synthesized and screened for antihypertensive activity. In general, compounds with a 2-substituted phenyl ring had higher activity than their 3- or 4-substituted counterparts or those containing heteroaryl groups. The 2-methylphenyl and 2-ethylphenyl derivatives 7 and 18 were the most potent members of the series. Preliminary studies indicated that the hypotensive action of these compounds was due to a direct relaxant effect on vascular smooth muscle.

Animals↗
PubMed1988

Antihypertensive thiadiazoles. 2. Vasodilator activity of some 2-aryl-5-guanidino-1,3,4-thiadiazoles.

Some 2-aryl-5-guanidino-(or N-substituted guanidino)-1,3,4-thiadiazoles and closely related analogues were found to lower blood pressure in metacorticoid (DOCA) hypertensive rats. In the unsubstituted guanidines that exhibited low toxicity, optimum activity resulted when the aryl group was a 2-methylphenyl ring (11). Modifications to the guanidine group did not increase antihypertensive activity, but, in the 2-methylphenyl series, the N-n-butyl- and N-(2-methoxyethyl)guanidines (63 and 78) and the related iminoimidazolidine 93 were of comparable activity to that of the unsubstituted guanidine 11. The iminoimidazolidine 93 showed a somewhat longer duration of action than the guanidine derivatives. Preliminary studies in a pithed rat preparation indicated that these thiadiazole derivatives (11, 63, and 93) lowered blood pressure by a direct relaxant effect on vascular smooth muscle.

Animals↗
PubMed1988

The effect of early functional activities on experimentally tenotomized Achilles tendons in rats.

Muscle atrophy, joint stiffness, osteoarthritis, infection, skin necrosis, atrophy and ulceration of joint cartilage and tendocutaneous adhesion are familiar complications produced by prolonged immobilization of surgically repaired tendon ruptures. Because these complications may be minimized by limited immobilization and early functional activities, we studied the effects of early weight bearing on the maximum breaking strength of tenotomized tendons in 30 Wistar rats. After tenotomy, the right hind limb of the first group of 10 rats was immobilized for the first 5 days. Thereafter their casts were removed to permit weight bearing for the next 3 days. In a second group of 10 rats, casts were removed 2 days after surgery, the animals were allowed 3 days of unrestricted use of the limb, and then the limbs were re-casted for another 3 days. In a third group of 10 rats the right hind limbs were casted throughout the first 8 days of healing. At the end of this time, strain gauge measurements showed that tendons in the second group healed significantly stronger and without rerupture than those in either of the two groups. Although healing time in rats does not directly translate to humans, our findings suggest that function may return faster in humans, as, for example, following Achilles tendon rupture, if a better combination of immobilization and activity could be found than is currently employed.

Achilles Tendon↗
PubMed1987

Low-intensity pulsed galvanic current and the healing of tenotomized rat achilles tendons: preliminary report using load-to-breaking measurements.

The possible beneficial effects of low-intensity, pulsed galvanic currents on the healing of tenotomized Achilles tendons was investigated in three groups (20 animals each) of male Sprague-Dawley rats. Treatments via implanted electrodes were given once daily for 15 minutes over a two-week period. Although a portable high-voltage galvanic stimulator was used, stimulus intensity was only 75 microA at a frequency of 10/sec. Tendons were tested after two weeks for the load required to rebreak them at the original tenotomy site. The group treated with anodal current withstood significantly greater loads (p less than 0.001) than did either the group which healed normally (ie, without stimulation) or the group treated with cathodal current.

Achilles Tendon↗
PubMed1978

Combined microwave therapy.

Fifty-two cases of advanced head and neck cancer were treated by 434-MHz radiowave hyperthermia which was combined with cobalt radiotherapy and/or radioactive gold grain implant. Complete resolution of primary and secondary lesions occurred in 94% of cases, and the survival rate after three years was 54%. Retrospective study of comparable series revealed 62.5% resolution rate, and 29% survival after treatment with hyperbaric oxygen and cobalt, while after conventional supervoltage therapy, the resolution rate was 36.5%, and only 19% survived for three years.

Cobalt Radioisotopes↗
PubMed1978

The effect of verticality perception on body balance in normal subjects.

The relation between verticality perception and body balance as influenced by perceptual style, age, and sex was investigated in 100 subjects. Perceptual style was measured by the Rod and Frame Test. Body balance data were obtained by two electromechanical force plates. The results of the measurements of perceptual style indicated that the younger groups were more accurate in estimating verticality than the older groups and that men were more accurate than women. With regard to the body balance shift data, however, no significant differences relative to age, sex, or perceptual style were found. The rejection of the hypothesis concerning body balance shift was interpreted in terms of the dominant influence of proprioceptive cues over visual cues in maintaining body balance. In normal standing activities, as long as the neuromuscular system is intact, conflicting stimuli from the visual field appear to have little effect on modifying body balance.

Adolescent↗
PubMed1977

Acute disseminated staphylococcal disease in childhood.

From 1964 to 1974 we treated 15 children who had acute disseminated staphyloccal disease. The majority were previously-well males over 5 years of age. Thirteen of 15 patients had one or more cutaneous lesions characteristic of staphyloccal septicemia. Fifty percent of extracutaneous foci of staphylococcal infection were not detected on hospital admission and one third of these lesions were noted for the first time at autopsy. An absolute polymorphonuclear cell count of greater than 10,000/cu mm or an absolute band-form count of greater than 500/cu mm, or both, correlated with the presence of one or more inadequately treated sites of infection. These foci were responsible for bacteremia continuing after the initiation of antimicrobial therapy and for prolonged fever. The overall mortality was 27%; three of the four deaths occurred in patients with predisposing medical conditions. In addition to prolonged antimicrobial therapy, all patients should be evaluated carefully for the presence of occult metastatic sites of staphyloccal infection.

Acute Disease↗
PubMed1977

Glucose-6-phosphate dehydrogenase (G6PD) activity of human sperm.

Sperm from normal human donors and a G6PD-A- individual were examined for x-linked glucose-6-phosphate dehydrogenase activity and autosomally linked 6-phosphogluconate dehydrogenase activity. With the use of fluorescence microscopy, we divised a procedure to visualise in individual sperm cells the fluorescence of reduced coenzyme NADPH formed by each of the two enzymes in the presence of appropriate substrates. We found significant differences in the population distribution of sperm expressing each of the two activities, and the ratio of the two activities in sperm homogenate is very different from the one found in erythrocyte lysates. The possibility of haploid gene expression has been considered in interpreting these results.

Electrophoresis, Disc↗