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Biomedical subjects

J Smith

Publications and source records attributed to J Smith.

At least 793 records · Page 44Linked to original sources
PubMed1992

The effects of electroconvulsive therapy on plasma insulin and glucose in depression.

The effects of ECT on plasma insulin and glucose were assessed in 20 depressed patients, during the first, third and fifth session of ECT. After each administration of ECT there was a significant rise in blood glucose and plasma insulin levels, both of which peaked at 15 minutes. Insulin responses tended to attenuate over the course of ECT, whereas the glucose responses were similar for all three treatments. ECT was effective in all patients, although two months after the last treatment nine patients had partially relapsed (Hamilton score greater than 15). Those who relapsed had a more attenuated insulin response at the fifth treatment than those who had remained well, which suggests that insulin response to ECT may be predictive of clinical outcome.

Aged↗
PubMed1992

Comparative contraceptive efficacy and mechanism of action of the norgestimate-containing triphasic oral contraceptive.

Norgestimate (NGM), a derivative of 19-nortestosterone with very specific affinity for the progesterone receptor, has been used in combination with ethinyl estradiol (EE) at low doses in both monophasic and triphasic oral contraceptives (OCs). An open-label comparative clinical trial was conducted with 4,234 healthy women using comparative clinical trial was conducted with 4,234 healthy women using triphasic levonorgestrel (LUG)/EE and NGM/EE through a total of 22,312 menstrual cycles. Contraceptive (LUG)/EE and NGM/EE through a total of 22,312 menstrual cycles. Contraceptive efficacy was excellent with both preparations, with no statistically significant between-regimen differences in pregnancy rates. The theoretical Pearl index was the NGM/EE triphasic, and 0.34 for the LNG/EE triphasic. Adverse experiences in groups were typical of those that may occur among women taking low-dose OC agents. was similar with the two preparations: 8.6% for the NGM/EE triphasic and 6.8% for the LNG/EE triphasic. In a separate mechanism of action study, specific endocrine parameters were investigated in 20 subjects using the NGM/EE triphasic for 4 cycles. Ovulation suppression was demonstrated in statistically significant decreases from pretreatment values in serum levels of luteinizing hormone, follicle-stimulating hormone, progesterone, and estradiol. Significant on-treatment increases in serum levels of sex hormone binding globulin evidenced minimal androgenicity. All hormonal values returned to or toward normal in the post-treatment cycle. The study results support those obtained in large noncomparative studies of the NGM/EE triphasic. This phased-dose combination suppresses ovulation and is a very effective, minimally androgenic contraceptive agent with a good safety profile.

Adolescent↗
PubMed1992

Suppressive effect of tetrahydrocannabinol on specific T cell subpopulations in the thymus.

The effects of THC (delta-9-tetrahydrocannabinol) on thymocytes from adult BALB/c mice were investigated following in vitro stimulation with the T cell mitogen Concanavalin A (Con A). Con A treatment resulted in a decrease in the relative percent of L3T4+/Ly2+ cells (double positive; immature) with a concomitant increase in the percent of Ly2 cells (suppressor/cytotoxic). No change in the percent of L3T4 cells (helper) occurred. In addition, Con A stimulation resulted in an increase in the absolute number of Ly2 cells, with no change in number of L3T4 cells. Stimulation with the mitogen led to an increase in fluorescence intensity (indicative of relative number of markers) of Ly2 markers on Ly2 single positive cells as well as on L3T4+/Ly2+ cells. There was a moderate mitogen induced increase of L3T4 markers, but only on L3T4 single positive cells. Exposure to THC resulted in a definitive suppressive effect on Con A induced thymus cell proliferation. The suppression was primarily evidenced in the single positive Ly2 subpopulations. Since the thymus is the source of immunocompetent lymphocytes to the secondary lymphoid organs, it seems plausible that marijuana negatively affects maturation of these cells in the developing individual.

Animals↗
PubMed1992

Comparison of doxycycline and a chemically modified tetracycline inhibition of leukocyte functions.

Tetracyclines (Tc's) have the ability to inhibit neutrophil (PMN) functions which may be of value in the treatment of neutrophil-driven pathologic processes. However, long term use of Tc's frequently lead to emergence of antibiotic resistant strains of bacteria. A chemically modified analogue of Tc, 4DTc, having minimal antibiotic activity was compared to Dc, a member of the Tc family, for its ability to inhibit neutrophil functions. 4DTc was significantly less effective at inhibiting PMN superoxide synthesis, PMA-induced degranulation and PMN-mediated RBC lysis than was Dc. 4DTc and Dc were equally as effective inhibiting monocyte, but not PMN, adherence to gelatin-coated surfaces. When incubated in media containing varying 4DTc or Dc concentrations, Dc accumulated in RBC's and PMN's at levels 3 times greater than that found for similar media levels of 4DTc. The data suggest that the lesser ability of 4DTc to inhibit several PMN functions as compared to Dc may be related to its reduced intracellular accumulation. It also suggest that Tc inhibition of monocyte adherence may be more influenced by extracellular than intracellular processes.

Cell Adhesion↗
PubMed1992

Assessing symptom improvement after elective prostatectomy for benign prostatic hypertrophy.

BACKGROUND: Elective surgery for benign prostatic hypertrophy requires estimates of likely improvement. METHODS: Data are from a prospective study of all patients without cancer who underwent transurethral prostatectomy. After eliminating patients for whom surgery was not elective, we examined symptom improvement. RESULTS: Surgery was effective in reducing symptoms for all but those with very mild preoperative symptoms. For the remainder, the average level of postoperative outcomes achieved was independent of the initial symptom severity. CONCLUSIONS: Elective prostatectomy is effectiveness for improving symptoms. The improvement is typically sustained, and for some symptoms improvement continues during the first year after surgery. Patients with severe symptoms were as likely to achieve the same level of postoperative improvement as were patients with less severe problems initially. However, patients with very mild symptoms benefited little or none from surgery.

Adult↗
PubMed1992

Screening for neuroblastoma in the northern region of England. Laboratory aspects.

Our pilot study for neuroblastoma screening started in 1986. The study has progressed through several phases, with use of several analytical methods to a procedure based primarily on the use of automated gas chromatography mass spectrometry. The northern region of England has a relatively static population of approximately 3.5 million, with an annual birth rate of 41,000. The region consists of 16 administrative health districts. In 4 years, we have screened 20,829 infants from four health districts. In this program, we screen all children at 6 months of age. A urine sample is collected on filter paper by a health visitor, either at the time of the infant's routine clinic visit or during the health visitor's follow-up visit at home. In the laboratory, the sample is dried and processed for analysis of homovanillic acid (HVA) and vanillylmandelic acid (VMA), using a benchtop Hewlett Packard gas chromatograph mass spectrometer. The results are related to the creatinine content of the urine. Using cut-off limits of 39 micrograms/mg of creatinine for HVA and 25 micrograms/mg of creatinine for VMA, 2,537 infants (12.2%) required a second paper sample and 527 infants (2.5%) were observed with a liquid urine collection. Of these, the conditions of nine infants with elevated levels of HVA or VMA were investigated clinically for the possible presence of neuroblastoma. Two infants were found to have neuroblastoma; the other seven showed no evidence of tumor. In addition, there were three children who, when screened at 6 months of age, had normal levels of HVA and VMA but in whom neuroblastoma subsequently developed.

Biomarkers, Tumor↗
PubMed1992

A pilot study of screening for neuroblastoma in the north of England.

A pilot study has been carried out to assess the feasibility of screening for neuroblastoma in 6-month-old infants in the north of England. A total of 20,829 infants were screened. Two true-positive cases were found, along with eight false-positive and three false-negative cases. It was shown that the concentrations of catecholamine metabolites in the urine are dependent on the creatinine content; centiles have been established to allow this relationship to be taken into account. Five of the eight false-positive cases would have been correctly assessed as normal if the new centiles had been used. Preliminary results lend support to the need for a well-designed study of neuroblastoma screening to be carried out, with death from this disease as the only end point.

England↗
PubMed1992

Outcome of respiratory distress syndrome at 28 days: a prospective longitudinal study.

Fifty eight newborn infants with respiratory distress syndrome (RDS) were prospectively studied, in order to determine clinical variables prognostic of poor outcome at 28 days. Twenty six infants survived without bronchopulmonary dysplasia (BPD), 13 had Type 1 BPD, 4 had Type 2 BPD and 15 infants died before 28 days. Survivors without BPD had higher birthweights and gestational ages. Among the other infants, severity of initial lung disease was the best discriminator between outcome groups: Type 1 BPD infants had the best lungs at onset, and the nonsurvivors had the worst lungs. Stepwise multiple logistic regression identified gestational age and the ventilatory index number 1 (VI1) (= respirator frequency x maximal inspiratory pressure) at day 3 as the most useful variables to predict "poor outcome" (nonsurvival or Type 2 BPD). Ninety five percent of the infants were correctly classified using a cut-off probability of 0.5. We conclude that RDS outcome at 28 days is determined at a very early stage and that poor outcome can be predicted with reasonable accuracy at three days of age.

Birth Weight↗
PubMed1992

What makes outpatient attendance worthwhile for patients?

All patients attending 10 general medical and general surgical outpatient clinics at a provincial teaching hospital were surveyed during a 1-week period. Questionnaires administered and completed by the patients at the time of the visit were used to establish the factors most closely associated with patients feeling that their consultations had been "very worthwhile". These were: consultations lasting more than 10 min, having received advice from a specialist and having been reassured. The study may provide a basis for a process of medical audit in outpatient departments and, thus, more appropriate services.

Adult↗
PubMed1992

Comparison of intranasal and intratracheal oxygen administration in healthy awake dogs.

Intranasal (IN) and intratracheal (IT) oxygen administration techniques were compared by measuring inspired oxygen concentrations (FIO2) and partial pressures of arterial oxygen (PaO2) in 5 healthy dogs at various IN (50, 100, 150, and 200 ml/kg of body weight/min) and IT (10, 25, 50, 100, 150, 200, and 250 ml/kg/min) oxygen flow rates. Intratracheal administration of oxygen permitted lower oxygen flow rates than IN administration. Each IT oxygen flow rate produced significantly higher FIO2 and PaO2 than the corresponding IN flow rate. An IT oxygen flow rate of 25 ml/kg/min produced FIO2 and PaO2 values equivalent to those produced by an IN oxygen flow rate of 50 ml/kg/min. An IT oxygen flow rate of 50 ml/kg/min produced FIO2 and PaO2 values equivalent to those produced by IN oxygen flow rates of 100 and 150 ml/kg/min. All IT oxygen flow rates greater than or equal to 100 ml/kg/min produced FIO2 and PaO2 values that were greater than FIO2 and PaO2 values produced by IN oxygen flow rates of 200 ml/kg/min. The lowest flow rates studied (50 ml/kg/min, IN, and 10 ml/kg/min, IT) produced PaO2 capable of maintaining 97% hemoglobin saturation, which should be adequate for most clinical situations. Arterial blood gas analysis and FIO2 measurements are necessary to accurately guide oxygen flow adjustments to achieve the desired PaO2 and to prevent oxygen toxicity produced by excessive FIO2.

Administration, Intranasal↗
PubMed1992

Poor prognosis acute myeloid leukaemia treated by matched unrelated donor marrow transplant without preceding total body irradiation.

Two patients with acute myeloid leukaemia, one in relapse after autologous bone marrow transplantation (BMT) (aged 52 years) and the other with primary resistant disease secondary to previously treated malignancy, have received marrow transplants from matched unrelated donors. Cytoreductive conditioning in both cases was with high-dose combination chemotherapy alone. Engraftment was aided by the administration of total lymphoid irradiation together with in vivo antilymphocyte antibody prior to marrow infusion. Both patients survive in complete remission, currently at 12 and 15 months post-BMT respectively. The avoidance of total body irradiation in BMT patients at high risk of early treatment-related mortality may be advantageous.

Adult↗
PubMed1992

Prosthetic management of hemicorporectomy patients: new approaches.

Functional outcome with hemicorporectomy prosthetic management has improved little in the last 20 years. Patient expectations for independence, comfort, and cosmesis have been disappointed with traditional bucket designs. This report describes the prosthetic management of a paraplegic patient who underwent hemicorporectomy at T12 secondary to complications from a lumbar ependymoma. Four successive prostheses were developed using foam and resin combinations, computer-assisted pressure monitoring, and interdisciplinary team feedback regarding design and fabrication. A total-contact bucket with removable liner was created, allowing management of the ileal diversion and colostomy. Prosthetic legs were attached to improve wheelchair balance and cosmesis. In his final prosthesis, the patient's function and appearance was equivalent to a well-rehabilitated midthoracic spinal cord trauma patient. Sitting tolerance exceeded 12 hours a day. Each prototype is discussed, including design, materials, fabrication process, patient acceptance and functional independence, and complications.

Adult↗
PubMed1992

Effects of increasing the rate of alcohol metabolism on plasma acetate concentration.

Plasma acetate concentration is increased during alcohol metabolism. However, measures which increase the rate of alcohol metabolism do not always increase plasma acetate concentration. Plasma samples from normal male subjects who had been given alcohol and then either fructose or glucose were analysed for acetate. Although each of these carbohydrates increased the mean rate of alcohol metabolism, only fructose increased the plasma acetate concentration. It was concluded that the further metabolism of acetate produced from alcohol may be increased by glucose.

Acetates↗