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Biomedical subjects

D R Smith

Publications and source records attributed to D R Smith.

At least 253 records · Page 14Linked to original sources
PubMed1986

Proenkephalin-A gene regulation in the rat striatum: influence of lithium and haloperidol.

This report explores the influence of lithium and haloperidol on (Met5)-enkephalin (ME) biosynthesis in the rat striatum. Male Fischer 344 rats were treated intraperitoneally with lithium chloride (4 mEq/kg/day) for 2, 4, or 6 days and sacrificed 24 hr after the last dose; in addition, the effect of lithium at 2 and 24 hr after a single dose was studied. Serum levels increased in a time-related manner on repeated administration of lithium. Lithium increased the striatal ME content (native ME) in a time-dependent fashion, reaching 160% of control following six doses; no changes in ME were observed in hypothalamus and hippocampus. ME levels recovered to control values 8 days after cessation of a 4-day course of repeated administration (4 mEq/kg/day) of lithium. In an attempt to characterize the nature of this selective increase of ME content in the striatum, the precursor content (cryptic ME) as well as the preproenkephalin mRNA abundance was determined. Lithium increased the precursor content in a time-dependent fashion and this pattern closely paralleled the increase in native ME content. The preproenkephalin mRNA abundance with respect to control was quantitated by blot-hybridization of total RNA with a 32P-labeled cDNA probe derived from rat brain. Lithium increased the mRNA abundance following repeated doses for 4 or 6 days. Concurrent administration of an opiate antagonist, naltrexone (5 mg/kg/day), for 4 days did not influence the changes induced by lithium. On repeated administration (1 mg/kg/day) for 4 days, the neuroleptic, haloperidol, increased the biosynthesis of ME which was more marked than that of lithium administered for the same period; the combination of a haloperidol and lithium regimen did not lead to an additive of synergistic effect. The results indicate that, like haloperidol, repeated injections of lithium increase the biosynthesis of ME in the basal ganglia by increasing the preproenkephalin mRNA abundance and translation process.

Animals↗
PubMed1986

The lymphokine "inhibitor of DNA synthesis" (IDS) suppresses human T lymphocyte proliferation by an interleukin-2-independent mechanism.

IDS is a soluble glycoprotein product of activated T cells that inhibits lymphocyte proliferation induced by antigens and by lectin mitogens. This immunosuppressive lymphokine has been distinguished from lymphotoxin, Proliferation Inhibitory Factor, Colony Inhibitory Factor, Macrophage Inhibitory Factor, and interferon. Using IDS partially purified by isoelectric focusing from culture supernatants of concanavalin A-stimulated human peripheral blood mononuclear cells (PBMC), we investigated IDS inhibition of T cell proliferation with respect to the interleukin pathway. At concentrations that produced 75-90% suppression of proliferation in PHA-stimulated PBMC cultures, IDS caused no decrease in interleukin 2 (IL2) production (determined by bioassay) or in IL2 receptor expression (determined with anti-Tac antibody). Moreover, adding exogenous IL2 to IDS-inhibited cultures failed to restore proliferation. IDS inhibited growth of several IL2-dependent and IL2-independent cell lines, and suppressed proliferation of PBMC induced by the phorbol ester TPA (12-0-tetradecanoyl-13-phorbol acetate) or by the calcium ionophore A23187, thus distinguishing its mechanism of action from that of cyclosporin A, dexamethasone, OKT11A antibody, and other inhibitors. These data extend earlier findings that IDS acts late in G1 phase of the cell cycle, and provide evidence that IDS inhibits T cell proliferation through an IL2-independent mechanism.

Animals↗
PubMed1986

Nosocomial nasal myiasis.

Sixty-five fly maggots were retrieved from the nasal cavity of an unconscious 64-year-old man who had been admitted 18 days earlier with diabetic hyperosmolar coma. The larvae were identified as Cochliomyia macellaria, an organism commonly associated with myiasis in the United States. The clinical time sequence indicates that this infection was acquired in the hospital. This incident provides further evidence that immobile and debilitated patients are at risk to acquire myiasis.

Animals↗
PubMed1985

Coronary artery luminal diameter in aortic stenosis.

The coronary artery luminal diameters in 32 patients with aortic stenosis (AS) were compared with those of 24 control subjects without left ventricular (LV) hypertrophy by means of a derived index. Patients with AS had significantly larger coronary arteries than the control subjects (p less than 0.01). The increase in coronary luminal diameter had a weak correlation to LV wall thickness (r = 0.32) and LV mass (r = 0.34). Among 21 patients with AS and normal coronary angiograms, those with angina had higher peak LV pressures (224 +/- 8 vs 196 +/- 7 mm Hg) and greater peak systolic gradients (103 +/- 9 vs 74 +/- 10 mm Hg) than those without angina (p less than 0.05). However, there was no significant difference in coronary artery diameters, peak LV stress or LV tension at rest between patients with and without angina.

Adult↗
PubMed1985

Directional asymmetry of body dimensions among white adolescents.

Asymmetry of paired dimensions has been recognized as a methodological problem in anthropometry and more recently as an indicator of environmental stress. This study seeks to determine the extent of directional asymmetry for some of the measurements commonly made in anthropometry. Upper arm circumference, biepicondylar breadth, triceps and subscapular skinfolds, bicondylar breadth of the femur, and calf circumference were measured on right and left sides among 135 white adolescents from suburban Philadelphia. Handedness (right or nonright) was subject-assessed. Body composition was estimated through underwater weighing. Asymmetry was evaluated using a paired t test. Arm measurements are significantly asymmetric in favor of the right side; subscapular skinfolds and leg measurements are not significantly asymmetric. Among the sample of right-handed subjects (n = 116), upper arm circumference and biepicondylar breadth were significantly larger on the right side, and, among the males of this subsample, triceps was as well. The nonright-handed subjects (n = 19) did not show statistically significant asymmetry. Asymmetry was negatively but weakly related to body composition. These results are consistent with an explanation in terms of preferred use of one side of the body and consequent muscle hypertrophy, but an adequate test of this explanation requires hypothesis testing in larger samples of nonright-handed subjects.

Adolescent↗
PubMed1985

Dirofilaria immitis in a portacaval shunt.

The fifth known case of intravascular human infection with an adult Dirofilaria immitis (canine heartworm) is reported. This mature, but nongravid, female nematode was recovered at autopsy from a prosthetic portacaval shunt. A brief review of human dirofilariasis is presented.

Adult↗
PubMed1985

Meeting family needs following severe head injury: a multidisciplinary approach.

Families of neurotrauma patients experience significantly increased stress during the acute phase of injury. It is important to recognize each family's needs during this period in order to enhance the potential for recovery. Assessment of individual needs, communication with the health care team, and genuine concern are necessary. One successful approach to the group process is "The Family Huddle", a technique which has enjoyed positive results at one institution.

Brain Injuries↗
PubMed1985

Nucleotide sequence of HBI, a novel recombinant MC29 derivative with altered pathogenic properties.

HBI is a recombinant avian retrovirus with novel pathogenic properties that was derived from the myc-containing virus MC29. In contrast to MC29, which causes endotheliomas in chickens, HBI induces lymphoid tumors. The results of molecular cloning and nucleotide sequencing of HBI reported here show that the virus contains sequences derived from both c-myc and ring-neck pheasant virus, in addition to MC29. The 3' half of the myc gene was largely replaced by c-myc sequences, and most of the long terminal repeat and gag regions were replaced by ring-neck pheasant virus sequences. The long terminal repeat contained a triplicate sequence which was homologous to the core enhancer sequence of the simian virus 40 72-base-pair repeat. The significance of these changes in relation to the unusual biological properties of the virus are discussed.

Amino Acid Sequence↗
PubMed1984

Domains of the positive transcription factor specific for the Xenopus 5S RNA gene.

The 40 kd positive transcription factor that interacts with the 50 nucleotide internal control region of 5S ribosomal RNA genes in Xenopus can be subdivided into three functional domains by proteolytic cleavage. At one end of the protein is a 10 kd domain that is required for efficient RNA transcription but not for binding to the DNA. This adjoins a second domain that binds to the 5' end of the internal control region, a region of the DNA known to contribute only weakly to binding the protein but one that is essential for RNA transcription. The removal of both of these protein domains leaves a half of the protein that binds only to the 3' side of the control region and is inactive in promoting transcription. Quantitative DNA binding and in vitro transcription experiments show that only a single molecule of 40 kd factor binds to the internal control region, and that this stoichiometry is sufficient to give maximal stimulation of 5S RNA transcription in a reconstituted system. Consideration of the essential DNA contact points of the factor, taken together with the constraints imposed by a 1:1 protein to DNA stoichiometry permit the linear projection of the extended protein molecule onto its binding site along the internal control region of the 5S RNA gene.

Animals↗
PubMed1984

Aging and religious participation.

With few exceptions, previous studies of the relationship between age and religious participation have either ignored the nonorganizational aspects of participation or have used a single measure of participation. Following an approach adopted in studies of the structure of well-being, we investigate the multidimensional conceptualization of religious participation. The results demonstrate that (a) the empirical definitions for the dimensions of participation are invariant over age groups, (b) there is a convergence in individuals' organizational and nonorganizational participation in the later stages of the life cycle, and (c) the dimensions of religious involvement become more distinct and determinant with increasing age.

Aged↗
PubMed1984

Use of the exercise maximal ST segment/heart rate slope in assessing the results of coronary angioplasty.

A new exercise test was used to assess the effects of coronary angioplasty in 22 patients. Twenty five angioplasty procedures were performed and the exercise maximal ST segment/heart rate slope was measured before and after operation on 23 occasions; in two patients treated for unstable angina the slope was measured only after the two procedures. Successful angioplasty (23 of the 25 procedures) resulted in a significant reduction of the maximal ST/HR slope, usually falling by the equivalent of single vessel disease according to previously published criteria. When angioplasty produced little angiographic change (two of the 25 procedures) the maximal ST/HR slope was not significantly altered. A second, and successful, angioplasty for these two patients led to a significant reduction of the maximal ST/HR slope. Twelve patients were restudied by coronary angiography and exercise testing approximately six months after angioplasty. Of these, six had experienced recurrent chest pain, and the exercise test successfully identified the three who had restenoses and the three who did not. Thus the maximal ST/HR slope was useful as a non-invasive and accurate method for following the progress of individual patients after coronary angioplasty.

Adult↗