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Biomedical subjects

J Smith

Publications and source records attributed to J Smith.

At least 1,171 records · Page 65Linked to original sources
PubMed1984

Bone sarcomas in Paget disease: a study of 85 patients.

This is a comprehensive review of 85 patients who had bone sarcoma associated with Paget disease and who were seen at Memorial Sloan-Kettering Cancer Center between 1927 and 1982. There was an almost equal distribution of tumors in the axial and the appendicular skeletons. The pelvis, humerus, femur, and skull were the tumor sites in 80% of cases. The tumors were bulky large soft tissue masses. Lytic lesions were more common than sclerotic lesions. Mixed lytic and sclerotic lesions were much less common than either single type. Periosteal reaction was uncommon and found in less than 7%. Methylene diphosphonate scans of the bone often showed a cold area that was associated with marked increase in uptake on the gallium scan. Angiography, which was performed in 13 patients, was useful, but CT was much more helpful in showing the soft tissue mass as well as the extent of bony disease. Only three patients in this study survived for five years. Present chemotherapy protocols were disappointing in the treatment of this highly lethal tumor.

Adult↗
PubMed1984

Psychiatric hospital admissions in Bristol. II. Social and clinical aspects of compulsory admission.

Three groups of patients admitted compulsorily from populations with markedly different rates of compulsory psychiatric admissions were compared on a range of social and clinical data. Whilst West Indian and white patients from inner city areas differed in many respects, they were both more likely than other patients to be referred to the psychiatric services through police agencies, with little GP involvement and were often admitted from public places following disturbed behaviour. However, levels of violence and threatening behaviour were no higher among inner city patients, black or white, and once admitted, these groups showed similar treatment compliance to white patients who had been admitted compulsorily from suburban areas. Implications for primary care and delivery of psychiatric services are discussed.

Adult↗
PubMed1984

Long term effects of administration of a gonadotropin-releasing hormone superagonist analog in men with prostatic carcinoma.

Administration of the superagonist analog of GnRH, D-Leu6-GnRH proethylamide, profoundly reduced plasma LH, FSH, testosterone, and dihydrotestosterone levels when given for 6-11 weeks to adult men with prostatic carcinoma. Since patients with prostatic carcinoma can be expected to receive this analog for as long as 3-4 yr, we questioned whether the same degree of reduction could be maintained during chronic administration. In 22 men who had received D-Leu6-GnRH proethylamide for at least 1 yr, LH and testosterone remained at the initial low levels. Plasma dihydrotestosterone concentrations, on the other hand, gradually fell further with long term administration. FSH levels reached a nadir of 5.7 +/- 0.94 (+/- SEM) mIU/ml at 10-11 weeks. Unexpectedly, the plasma levels of this gonadotropin then gradually increased, and between 25 and 97 weeks were approximately 10-15 mIU/ml. This pattern occurred identically in patients receiving either 1 or 10 mg D-Leu6-GnRH proethylamide daily. These data indicate persistent suppression of LH and androgen levels during prolonged therapy and suggest that D-Leu6-GnRH-induced "medical castration" can be maintained with chronic administration.

Aged↗
PubMed1984

Effects of heat stress on day-old broiler chicks.

Short-term heat stress can occur when chicks are transported from the hatchery to growing facilities. Two experiments were conducted to determine the possible effects of short-term heat stress on growth and feed conversion of broiler (Hubbard X Hubbard) chicks. The heat stress was accomplished by placing chicks in Jamesway 252 incubators at dry bulb temperatures ranging from 40 to 45 C for variable times. Growth, feed consumption, and mortality were measured for 16 days following the heat stress. Short sublethal heat stress significantly reduced growth rate to 16 days in these experiments without any effect on feed conversion ratio. The results indicate that the hatchery industry should avoid overheating chicks even for periods as short as 1 hr.

Animals↗
PubMed1984

Polyclonal activation of the murine immune system by an antibody to IgD. VII. Demonstration of the role of nonantigen-specific T help in in vivo B cell activation.

Previous studies from this laboratory have shown that the injection of mice with an affinity-purified goat antibody to mouse IgD (GaM delta) induces T-independent polyclonal increases in: 1) B cell DNA synthesis, and 2) expression of surface Ia antigen and receptors for T helper factors, 1 to 2 days after injection. In addition, T-independent polyclonal increases in B cell number and IgG1 secretion are observed 6 to 7 days after injection. The administration of normal goat IgG (GIgG) along with GaM delta has been shown to augment GaM delta-induced polyclonal IgG1 secretion. To obtain information about the characteristics of the T help that is required for polyclonal antibody production in this model system, we investigated: 1) the length of the period during which GaM delta must be present to induce day 7 polyclonal antibody production, and 2) the kinetics of the induction of splenic T cell DNA synthesis. We found that GaM delta can be neutralized 3 days after injection by the administration of IgD without decreasing day 7 polyclonal IgG1 secretion, as long as mice are given GIgG at the time that GaM delta is neutralized. In contrast, polyclonal IgG1 secretion is greatly inhibited if GaM delta is neutralized 1 to 2 days after injection or if GaM delta is neutralized 3 days after injection, but GIgG is not administered at this time. Because GIgG can stimulate activated GIgG-specific T cells to secrete helper factors, but, unlike GaM delta cannot focus GIgG-specific T help polyclonally onto B cells, these findings suggest that nonspecific T help, rather than antigen-specific T help, is required in this system after day 3 for the induction of polyclonal IgG1 secretion. Determination of the kinetics of the induction of T cell DNA synthesis in this system by in vivo [3H] thymidine incorporation studies, as well as dual laser fluorescence-activated cell sorter analysis of T and B cell DNA content, indicate that T cells are induced to synthesize DNA 2 days after GaM delta injection and reach plateau rates of DNA synthesis 3 days after injection. Taken together, the GaM delta neutralization experiments and DNA synthesis studies suggest that one reason that GaM delta is required for 3 days in this system is to allow maximal activation of GIgG-specific T cells, which when stimulated later by GIgG secrete nonantigen-specific helper factors that induce GaM delta-activated B cells to secrete IgG1.

Animals↗
PubMed1984

Argon laser trabeculoplasty: comparison of bichromatic and monochromatic wavelengths.

A randomized prospective study was undertaken to examine the effects of bichromatic argon laser therapy and monochromatic argon laser therapy when used for trabeculoplasty in chronic open angle glaucoma. Fifty patients underwent laser trabeculoplasty with the continuous wave argon laser emitting wavelengths of multiple lines (454.5 nm to 528.7 nm) in the bichromatic spectrum (blue and green). Fifty additional patients underwent laser trabeculoplasty using a continuous-wave argon laser emitting a monochromatic (green) wavelength at 514.5 nm. Patients treated with the bichromatic laser had an average decrease in their intraocular pressure of -7.1 +/- 5.2 mmHg and patients treated with the monochromatic laser had an average decrease of -8.0 +/- 6.2 mmHg. The length of the follow-up was 2 to 13 months with an average of 10 months. For each group, this decrease in intraocular pressure from the pretreatment values was statistically significant (P less than 0.001). However, there was no statistically significant difference in the decrease in the intraocular pressure between the two groups (P = 0.34). No differences were noted in the postoperative course or in the complication rate between the two groups.

Aged↗
PubMed1984

Glucocorticoids stimulate adrenergic differentiation in cultures of migrating and premigratory neural crest.

Glucocorticoid hormones stimulate catecholamine (CA) anabolism in a variety of adrenergic derivatives of the neural crest. We describe work performed to investigate the action of these steroids on the catecholaminergic differentiation of neural crest cells themselves. Crest was taken from the trunk level of 2-day quail embryos, before migration had begun, and was cultured in vitro. Adrenergic differentiation, characterized by the ability of the cultures to synthesize and store CA, was minimal and was not improved when glucocorticoids were added to the medium. In contrast, extensive adrenergic differentiation occurred when neural crest cells, removed from the embryo 24 hr later, toward the end of their migratory phase, were cultured with the sclerotomal component of the somite (their immediate embryonic microenvironment). This process was considerably stimulated by corticosteroids; the rate of conversion of [3H]tyrosine to intracellular CA (norepinephrine, epinephrine, and dopamine) was 2 to 3 times higher in cultures exposed for 7 days to 10(-6) to 10(-7) M hydrocortisone, corticosterone, or dexamethasone, and the diameter of the dense-core vesicles seen in cell bodies and processes after permanganate fixation was strikingly increased. The effect was specific for the adrenergic phenotype in that acetylcholine synthesis by the cultures was consistently unaffected by hormone treatment. We infer that glucocorticoids do not trigger adrenergic differentiation, but that they selectively enhance catecholaminergic properties in crest cells that have already been exposed to an appropriate signal of another kind. This conclusion is strengthened by the observation that glucocorticoids stimulated the development of CA-producing cells from premigratory crest grown in the presence of somites and notochord, postulated sources of factors initiating adrenergic differentiation in the embryo. Although the intervention of glucocorticoids in vivo at very early embryonic stages remains to be established, our results indicate that neural crest derivatives would be potentially responsive to these hormones as soon as the sympathetic ganglia form.

Animals↗
PubMed1984

Direct estimation considered within a comparative judgment framework.

Two experiments that employed the dimension of line length were conducted to support an interpretation of direct estimation within the framework of comparative judgment. It was reasoned that because memorial and processing demands increased, decreasing amounts of transmitted information should be found in discrimination, categorization, and estimation tasks when considered in that order. The data of the first experiment supported the prediction. However, external anchors provided to reduce demand in estimation had no apparent effect. A second study did indicate a marginal effect of anchors when subjects were instructed to employ them but, more strikingly, demonstrated that the shape of the psychophysical function was sensitive to the differential labels that accompanied the anchors. Labels derived from a Fechnerian assumption about psychophysical relations produced a Fechnerian function, whereas labels derived from the actual ratio of the stimulus line to the largest line produced a function consistent with Stevens's power law. It was concluded that the evidence favored a view of direct estimation consonant with cognitive interpretations rather than with the idea of a universal psychophysical function.

Cognition↗
PubMed1984

Urethral strictures following cardiac surgery.

During the period July 1979 to December 1980 a series of urethral strictures developed following catheterisation for cardiac surgery in this hospital. Catheterisation was for monitoring purposes and the operation, in the majority of cases, was a coronary artery bypass graft procedure. The typical stricture extended along the anterior urethra as far as, but not including, the bulbous urethra. The presentation, diagnosis and subsequent management are outlined and possible aetiological factors are discussed.

Adult↗
PubMed1984

Effect of association, dissociation and positive self-talk strategies on endurance performance.

The purpose of the present investigation was to compare associative, dissociative and positive self-talk strategies in the performance of two endurance tasks. In Experiment 1, subjects (N = 40) were asked to employ one of these strategies during a 30 minute run around a quarter mile track. Subjects were instructed to run as fast and as far as they could during the allotted time. Heart rate, feelings, and cognitions were also assessed. Results indicated no significant between group differences on either performance or questionnaire measures. In Experiment 2, subjects (N = 230) were asked to employ the same cognitive strategies as described above throughout the duration of a muscular leg-endurance task. Results showed that the dissociation and positive self-task conditions produced significantly greater persistence than the association or control conditions. No significant differences were found for heart rate and other questionnaire data. The findings are discussed in terms of task type, the processing of internal and external cues and the mediating role of previous experience in affecting subjects' use of these cognitive strategies. Future directions for research are offered.

Adaptation, Psychological↗