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Biomedical subjects

J Moore

Publications and source records attributed to J Moore.

At least 613 records · Page 34Linked to original sources

Cimetidine in elective Caesarean section. Effect on gastric acidity.

Aspiration pneumonitis, Mendelson's syndrome, continues to be an important cause of maternal morbidity and mortality in obstetric anaesthesia, despite widespread adoption of the practice of routine administration of alkalis. Histamine H2 receptor blocking drugs have been shown to reduce gastric secretion in non-obstetric patients. Cimetidine was given intravenously to fasting patients before elective Caesarean section. In all 10 patients who received cimetidine 200 mg intravenously at 60--80 minutes before anaesthesia, the pH of gastric contents at the time of induction was above 2.5. When the interval between administration of the drug and induction of anaesthesia was only 30--40 minutes (six patients) or was over 90 minutes (20 patients) then the pH was raised to above this value in only two-thirds of patients. By contrast eight of 10 untreated patients were found to have a gastric pH of less than 2.5. No adverse effects of cimetidine were seen in mothers or infants.

Anesthesia, General↗

Evaluation of midazolam as an intravenous induction agent.

Midazolam, a new water-soluble benzodiazepine, was investigated as an intravenous anaesthetic agent in 260 adult patients in doses ranging from 0.15 to 0.5 mg/kg using a variety of premedications. Its onset of action was generally slow, taking up to 3 minutes to exert its maximum effect. A wide variability in response was found in that some unpremedicated patients were satisfactorily anaesthetised with 0.15 mg/kg while other were only moderately sedated following doses of 0.5 mg/kg. Less variability was found in the elderly who also required smaller doses. Narcotic premedication potentiated the sedative effect of midazolam. Few respiratory or cardiovascular effects were noted apart from hiccough following the larger doses. The incidence of venous sequelae was much lower than that found following diazepam.

Adolescent↗

The placental transfer of cimetidine.

The placental transfer of cimetidine 200 mg intravenously was investigated in 16 patients in normal labour and 40 patients undergoing elective Caesarean section. Cimetidine crosses the placental barrier, blood levels at delivery in mothers and infants being lower with increasing time from injection. Umbilical cord blood cimetidine levels are markedly lower than those of the mother during the first hour following administration but thereafter levels are similar. The mean fetal-maternal ratio at delivery was highest (0.84) at 1 1/2-2 hours following administration. Postdelivery infant and maternal blood samples showed that cimetidine could not be detected, in most cases, 19 hours following administration. The relevance of these findings is discussed.

Cesarean Section↗

Mental neuropathy from systemic cancer.

Nineteen patients with mental neuropathy secondary to systemic cancer are described. In nine patients, the numb chin was the presenting symptom of a neoplasm. Nine patients had lymphoreticular malignancies, and the others had a variety of solid tumors. Radiograms of the mandible were abnormal in 5 of 12 patients. The cerebrospinal fluid contained malignant cells in two. Resolution, complete or partial, occurred in 16 of 19 patients receiving radiation or chemotherapy, including 8 who received chemotherapy alone. Sixteen of the 19 patients died within 17 months of the onset of the neuropathy. A nontraumatic mental neuropathy should initiate a search for cancer.

Adult↗

Drug-induced thrombocytopenia is associated with increased binding of IgG to platelets both in vivo and in vitro.

Thrombocytopenia is a common serious adverse effect of drug treatment. A variety of in vitro diagnostic techniques to confirm the diagnosis are available, but the majority lack sufficient sensitivity to detect all cases of drug-induced thrombocytopenia. We studied 19 patients with suspected drug-induced thrombocytopenia and demonstrated that platelet-associated IgG (PAIgG) was elevated in all at the time of thrombocytopenia, and PAIgG returned to normal levels as the thrombocytopenia resolved. In the majority of patients, the platelet count rapidly returned to normal after the drug was discontinued; however, in six patients, the thrombocytopenia persisted well beyond the period of time that the offending drug would be expected to be cleared from the blood. In 13 patients, serum obtained after recovery was used to identify the drug responsible for the thrombocytopenia in an in vitro assay. In all cases, the addition of the drug historically associated with the thrombocytopenic episode was associated with an increased binding of IgG to control platelets. For uncertain reasons, the concentration of drug required to increase the in vitro binding of IgG to test platelets was often more than the concentration usually achieved in vivo. Wider application of these techniques may provide better understanding of the clinical characteristics and mechanisms responsible for drug-induce thrombocytopenia.

Adult↗

The development and application of a serum assay for platelet-bindable IgG (S-PBIgG).

Direct assays for PAIgG are useful in diagnosing ITP and investigating mechanisms of thrombocytopenia. A serum assay for S-PBIgG would offer technical advantages in transportation and storage of samples and could prove useful in the diagnosis of thrombocytopenia caused by alloantibodies. We report the development of an assay for S-PBIgG that is positive in the majority of patients with immune thrombocytopenia. This was accomplished by empirically testing a number of variables, including the anticoagulant used to prepare target platelet, the presence of a fixative, incubation time, and the target platelet count. The development of this assay was facilitated by using a microtiter modification of the antiglobulin consumption assay, which was validated by simultaneously determining PAIgG with each method (r = 0.91, p less than 0.01, n = 42). The serum assay was then applied to the study of several types of immune thrombocytopenia PAIgG and S-PBIgG were simultaneously quantitated on platelets and sera obtained from 42 patients with idiopathic thrombocytopenia. PAIgG was elevated in 38 and S-PBIgG elevated in 34. Eleven patients had a normal or only moderately elevated S-PBIgG but a considerably elevated PAIgG. In these patients the unbound platelet antibody or immune complex may have platelet specificity. In the remaining patients there was a close correlation between the level of PAIgG and S-PBIgG (r = 0.81, n = 31) indicating that the bound platelet antibody or immune complex is dynamic equilibrium with the unbound. The potential application of the assay for S-PBIgG was demonstrated in three leukemic patients who were refractory to platelet transfusions and in two mothers who had infants with alloimmune neonatal thrombocytopenia. In these patients elevated S-PBIgG was associated with a normal or only slightly elevated PAIgG.

Antibodies↗

Changes in serum enzyme levels following ketamine infusions.

The levels of four serum enzymes, known to be elevated in toxic hepatitis, were measured preoperatively and on the 3-4th and 13-15th postoperative days in patients anaesthetised with ketamine infusions (54) or with a standard technique (64). Significant elevations in enzyme levels were considered to have occurred when the postoperative levels were outside the accepted normal range and had increased by more than 3 X SD from controls. About half the patients in each group had minor gynaecological operations and 2/20 in the ketamine series had postoperative elevation of enzyme levels, with no changes in the non-ketamine group. Following intermediate operations 14/34 anaesthetised with ketamine showed abnormal enzyme levels compared with 7/34 who had standard operations. None of the latter had more than one abnormal test as compared with six in the ketamine series. The causes and significance of these findings are not known.

Adult↗

Annual variations in plasma levels of testosterone and luteininzing hormone in the laboratory male mongrel dog.

Blood samples, drawn every 15 days (September 1975-September 1976) from four laboratory-housed male mongrel dogs, were assayed by radioimmunoassay for levels of testosterone and LH in the plasma. The mean plasma concentrations of testosterone remained relatively constant for most of the year with the exception of a significant rise in late August and early September. Mean plasma levels of LH showed a cyclic pattern throughout the year which could be represented by a cosine function curve. However, this cyclic pattern of LH was not accompanied by cyclic changes in plasma levels of testosterone and there was no relationship between these two hormones during the period of 1 year. As the cyclic pattern of LH was altered, the plasma level of testosterone began to rise and reached its highest concentration. Since this alteration of the LH cycle occurred before the increased concentrations of testosterone, and since there was no relationship between these two hormones for the period of a year, we have concluded that there may be another hormone(s) involved which either alters the sensitivity of the canine testis to LH or alters the Lh synthesis/release mechanism of the pituitary gland.

Animals↗

Uncertainty reduction, conditioned reinforcement, and observing.

In a concurrent-chains procedure, pigeons chose between equivalent mixed and multiple fixed-interval schedules of reinforcement. In the first experiment, preference for the multiple schedule was higher when the probability of the shorter fixed interval was less than .50 than for complementary points, an outcome consistent with the delay-reduction hypothesis of conditioned reinforcement and observing, but inconsistent with the uncertainty-reduction hypothesis which requires symmetrical preferences with a maximum when the two intervals are equiprobable. A second experiment assessed preference for equivalent mixed and multiple schedules when each choice outcome resulted in two reinforcements, one on the longer and one on the shorter fixed interval. The order of the two fixed intervals was determined probabilistically. Pigeons again preferred multiple to mixed schedules, although multiple-schedule preference did not vary systematically with the likelihood of the shorter fixed interval occurring first. The results from these choice procedures are consistent with those from the observing-response literature in suggesting that the strength of a stimulus cannot be well described as a function of the degree of uncertainty reduction the stimulus provides about reinforcement.

Journal Article↗

Stimulation of hepatic regeneration after partial hepatectomy by infusion of a cytosol extract from regenerating dog liver.

A cytosol liver extract was prepared from adult dog livers and from liver remnants that had been regenerating for one, two and three days after 72 per cent partial hepatectomy. Given intraportally, the most active of these cytosols did not stimulate proliferation in the livers of normal dogs. However, infused during a six hour period into the portal vein of test group dogs, the cytosol from 48 and, especially, 72 hour regenerating livers augmented the regeneration response ordinarily produced by 44 per cent partial depatectomy. The effect was delayed. It became identifiable 48 hours after infusion and rached a peak at 72 hours. Neither augmentation nor significant inhibition of the normal regeneration response was produced by cytosol from normal liver and 24 hour regenerating liver or by six hour infusion of insulin. The amplification effect of active cytosol was equivocal when the infusions were given intraperitoneally and was not demonstrable at all by the intravenous route. In these investigations, it is confirmed that there are growth control factors in regenerating liver but the nature or physiologic significance of the factor or factors has not been clarified.

Animals↗

Preventing malignant-cell transfer during endoscopic brush cytology.

Transfer of malignant cells on cytology brushes was responsible for false positive cytology reports in 4 patients. In 24 examinations of cytology brushes after patients with gastric carcinoma had been previously endoscoped, malignant cells were identified on 7 occasions. Satisfactory irradication of malignant cells was achieved by autoclaving the brushes for 15 min, not by cleaning with chlorhexidine or pancreatin. Although these observations may argue against the use of non-disposable brushes, non-disposable brushes provide a higher yield of cells and are cheaper than disposable brushes.

Cell Count↗

Comparison of brush cytology before or after biopsy for diagnosis of gastric carcinoma.

A randomized trial has compared the results of brush cytology before or after biopsy in patients with solitary gastric lesions. One hundred and eleven carcinomas were identified in 324 patients. False positive histological reports were recorded in 2 patients but there were no false positive cytology results. The cumulative accuracy of biopsy and cytology in patients with carcinoma was 97 per cent, which was significantly better than biopsy alone (83 per cent, P less than 0.001) or cytology alone (87 per cent, P less than 0.001). The cumulative results of brushing before biopsy were significantly better than results obtained by brushing after biopsy (P less than 0.05) and indicate that brush cytology should normally be performed before biopsy.

Biopsy↗