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Biomedical subjects

J Clarke

Publications and source records attributed to J Clarke.

At least 307 records · Page 17Linked to original sources
PubMed1983

Coronary artery surgery and direct coronary artery thrombolysis during acute myocardial infarction.

Twelve patients underwent direct coronary artery streptokinase thrombolysis during acute evolving myocardial infarction. Ten patients had restoration of orthograde pulmonary blood flow. Eight patients had significant myocardial salvage and clinical stabilization. Nine patients had subsequent coronary artery bypass surgery with no major hematological or cardiac complications. Five of these had surgery performed immediately. Two patients with no myocardial salvage after streptokinase had urgent surgery because of other critical coronary lesions. Seven patients with thrombolytic salvage of myocardium underwent urgent coronary artery bypass surgery without incident. The occurrence of two reinfarctions in streptokinase-improved patients waiting for surgery suggests that delay is unwarranted and coronary bypass surgery is needed to insure success.

Arrhythmias, Cardiac↗
PubMed1982

Effect of short-term infusion of sodium nitroprusside on mortality rate in acute myocardial infarction complicated by left ventricular failure: results of a Veterans Administration cooperative study.

Eight hundred twelve men with presumed acute myocardial infarction and left ventricular filling pressure of at least 12 mm Hg participated in a randomized double-blind placebo-controlled trial to assess the efficacy of a 48-hour infusion of sodium nitroprusside. The mortality rates at 21 days (10.4 per cent in the placebo group and 11.5 per cent in the nitroprusside group) and at 13 weeks (19.0 per cent and 17.0 per cent, respectively) were not significantly affected by treatment. The efficacy of nitroprusside was related to the time of treatment: the drug had a deleterious effect in patients whose infusions were started within nine hours of the onset of pain (mortality at 13 weeks, 24.2 per cent vs. 12.7 per cent; P = 0.025) and a beneficial effect in those whose infusions were begun later (mortality at 13 weeks, 14.4 per cent vs. 22.3 per cent; P = 0.04). Nitroprusside should probably not be used routinely in patients with high left ventricular filling pressures after acute myocardial infarction. However, the results in the patients given late treatment suggest that those with persistent pump failure might receive sustained benefit from short-term nitroprusside therapy.

Aged↗
PubMed1982

Role of veiled cells in lymphocyte activation.

Peripheral blood lymphocytes from normal rabbits or from rabbits hyperimmunized with human immunoglobulin were cultured in 20-microliters hanging droplets. The cultures were stimulated with concanavalin A or, in the case of cells from sensitized animals, with human immunoglobulin. The addition to the cultures of small numbers of autologous or allogeneic veiled cells separated from afferent lymph increased the responses to low doses of the stimulants, particularly when the cells were cultured at low cell densities or for short periods of time. At high cell densities or at longer periods of culture, stimulation occurred in the absence of added veiled cells and was associated with clumping of the lymphoid cells and development of cells which morphologically resembled veiled cells found in afferent lymph. The enhanced responses upon addition of small numbers of veiled cells were also correlated with the formation of lymphoid aggregates which were frequently held together by the elongated processes of a single veiled cell. The observations support the view that the veiled cells are lymph-borne precursors of dendritic cells in the lymph nodes. This may provide an in vitro model for the cellular relationships which occur in paracortical cords of lymph nodes following antigenic stimulation.

Animals↗
PubMed1982

The effect of veiled cells on lymphocyte function.

The response of lymphocytes to stimulation with Con A has been studied in the presence of veiled cells collected from the afferent lymph. In these enriched cultures the response occurred earlier with smaller numbers of lymphocytes and at lower concentrations of Con A. Veiled cells also caused clumping of lymphocytes in unstimulated cultures. In stimulated cultures small cells with veil-like projections appeared after 48 hr, but were not seen in unstimulated cultures.

Animals↗
PubMed1981

Development of an education program for parents of children with cancer.

A structured education program for parents of children with cancer has been developed and has undergone pilot testing. Content included both medical and psychosocial materials. The parent education program supplemented the existing educational and emotional support services of a large, childhood cancer treatment center. Written materials, self-instructional exercises, lectures, visual aids, and small group discussions were incorporated into the program. This variety of topics and teaching techniques was appealing to parents and appeared to enhance learning. Parents enthusiastically attended the program pilots, gained and retained the new information, and appeared to benefit emotionally from their participation.

Child↗
PubMed1981

Effects of inhibiting prolactin secretion on the maintenance of embryonic diapause in the suckling rat.

Treatment of rats with bromocriptine between days 5 and 8 after the post-partum mating resulted in suppression of serum prolactin levels and caused luteal regression. Although this treatment led to embryonic resorption when suckling was prevented by removing litters soon after birth, the diapausing embryos of animals nursing a litter of eight pups were unaffected by the treatment. These results suggest that the high levels of prolactin and progesterone in the circulation during lactation are not responsible for maintenance of the diapausing state.

Animals↗
PubMed1980

Effect of the cholesterol content of small unilamellar liposomes on their stability in vivo and in vitro.

Small unilamellar neutral, negatively and positively charged liposomes composed of egg phosphatidylcholine, various amounts of cholesterol and, when appropriate, phosphatidic acid or stearylamine and containing 6-carboxyfluorescein were injected into mice, incubated with mouse whole blood, plasma or serum or stored at 4 degrees C. Liposomal stability, i.e. the extent to which 6-carboxyfluorescein is retained by liposomes, was dependent on their cholesterol content. (1) Cholesterol-rich (egg phosphatidylcholine/cholesterol, 7:7 molar ratio) liposomes, regardless of surface charge, remained stable in the blood of intravenously injected animals for up to at least 400min. In addition, stability of cholesterol-rich liposomes was largely maintained in vitro in the presence of whole blood, plasma or serum for at least 90min. (2) Cholesterol-poor (egg phosphatidylcholine/cholesterol, 7:2 molar ratio) or cholesterol-free (egg phosphatidylcholine) liposomes lost very rapidly (at most within 2min) much of their stability after intravenous injection or upon contact with whole blood, plasma or serum. Whole blood and to some extent plasma were less detrimental to stability than was serum. (3) After intraperitoneal injection, neutral cholesterol-rich liposomes survived in the peritoneal cavity to enter the blood circulation in their intact form. Liposomes injected intramuscularly also entered the circulation, although with somewhat diminished stability. (4) Stability of neutral and negatively charged cholesterol-rich liposomes stored at 4 degrees C was maintained for several days, and by 53 days it had declined only moderately. Stored liposomes retained their unilamellar structure and their ability to remain stable in the blood after intravenous injection. (5) Control of liposomal stability by adjusting their cholesterol content may help in the design of liposomes for effective use in biological systems in vivo and in vitro.

Animals↗
PubMed1980

Experience with the CAM vision stimulator: preliminary report.

Eighty-four children with at least 2 lines of amblyopia were treated with the CAM vision stimulator. 91% of the children who had received no previous amblyopia therapy showed improvement, 73% achieving 6/12 vision or better. Of children in whom previous occlusion therapy had failed 73.8% improved. The treatment appears to be effective, rapid, and well tolerated. Our initial impressions have been sufficiently favourable to stimulate further clinical evaluation.

Adolescent↗
PubMed1980

Prosthetic replacement in femoral neck fractures.

Despite refinement of the guidelines for the use of an endoprosthesis in the management of femoral neck fractures and for the use of bone cement, no universally accepted treatment regimen currently exists. In order to collect statistically significant data about the "unsolved fracture," prospective studies from several centers must be undertaken. However, until such data are available, we submit the following conclusions about the patient with a cemented endoprosthesis for a femoral neck fracture. The early results are satisfactory--patients experience relatively little pain. Femoral fixation is enhanced--loosening occurs less frequently. The complications of prosthetic replacement are not increased by the use of cement fixation.

Femoral Neck Fractures↗
PubMed1979

[HbA1c: need of its dosage in diabetics (author's transl)].

HbA1c is the product of a slow, virtually irreversible reaction, occurring continuously throughout the 120 day life-span of the erythrocyte, between HbAo and glucose. It has been shown to represent the time-averaged blood glucose concentration of the preceeding 2 month period, and is independant of day to day fluctuations in the blood glucose concentration. HbA1c therefore acts as a biochemical marker and permits clinicans, by one test, to judge the quality of the diabetic control, in their patients.

Blood Glucose↗