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Biomedical subjects

M J Bennett

Publications and source records attributed to M J Bennett.

At least 307 records · Page 17Linked to original sources
PubMed1978

Outpatient problems: intermenstrual bleeding.

Intermenstrual bleeding in young girls is frequently a symptom that disappears spontaneously, but in adults it is best regarded as a symptom of intrauterine pathology. In patients in the late reproductive phase of life it may be the first symptom of uterine carcinoma and should therefore be treated with the same respect as postmenopausal bleeding. Treatment usually presents lille problem in patients who are properly investigated (Table 1).

Adolescent↗
PubMed1977

Maternal serum-alpha-fetoprotein and low birth-weight.

High maternal serum-alpha-fetoprotein (A.F.P.) concentrations in the first half of pregnancy were associated with prematurity and high perinatal mortality. 94 singleton pregnancies without neural-tube defects but with A.F.P. levels equal to or greater than three times the normal median resulted in the birth of infants weighing, on average, 357 g less than controls (P less than 0-001). The mean head circumference of the infants was also smaller than that of the controls. The 1 stillbirth and 3 neonatal deaths yielded a mortality-rate more than three and a half times that for singleton births without neural-tube defects at the same hospital in the years 1974-76. The results suggest that some pregnant women who will deliver low-birth-weight infants at high risk of perinatal death may be identified by means of serum-A.F.P. measurement early in pregnancy.

Abortion, Spontaneous↗
PubMed1977

Haemodynamic responses to isoflurane anaesthesia and hypovolaemia in the dog, and their modification by propranolol.

In six dogs chronically implanted with flow and pressure transducers, equipotent inspired concentrations of halothane and isoflurane were determined as the minimum inspried concentration of each agent which would abolish an individual dog's response to paw clamping. In equipotent concentration, isoflurane (1.2%, SD 0.2%) caused less myocardial depression than halothane (1.0%, SD 0.1%). Dose-response studies were possible up to a mean inspired isoflurane concentration of 3.0%, both before and after propranolol 0.3 mg kg-1, i.v. After propranolol, sensitive indices of myocardial contractility were depressed at all concentrations of isoflurane, indicating a moderate degree of beta-receptor activation by isoflurane. The haemodynamic response to hypovolaemia during isoflurane anaesthesia was not modified by propranolol.

Anesthesia, Inhalation↗
PubMed1977

The development of glycolytic and pentose phosphate shunt enzymes in human brain.

A quantitative enzyme analysis of 32 fetal human brains of 6--42 weeks gestational age range was carried out for the major glycolytic and pentose phosphate shunt enzymes. A critical period of raised enzyme levels was observed at 14 weeks. The glycolytic rate was probably controlled by the activities of hexokinase and phosphofructokinase which appear from the development patterns to have independent genetic sites. A rise in most enzyme activities was experienced in the final weeks of gestation towards levels consistent with those of adult tissues. Pentose phosphate shunt enzyme levels remained virtually unchanged during gestation after 14 weeks.

Brain↗
PubMed1976

Postabortal and postpartum tetanus. A review of 19 cases.

The occurrence of postabortal and postpartum tetanus over a 7 1/2-year period at Groote Schuur Hospital, Cape Town, is reviewed. Of all the women between the ages of 15 years and 50 years who were admitted with tetanus, 34,7% were admitted after abortions. The mortality rate was 15,8%, which appears to be the lowest thus far reported. Possible methods of preventing postabortal tetanus are discussed.

Abortion, Incomplete↗
PubMed1976

Haemodynamic interactions of high-dose propranolol pretreatment and anaesthesia in the dog. I: Halothane dose-response studies.

The effect of pretreatment for 3 weeks with propranolol 20 mg/kg/day on cardiovascular function during increasing depths of halothane anaesthesia (range 1.0-2.5% inspired halothane with IPPV and normocapnia) were studied in a group of seven closed-chest dogs which had been implanted previously with cardiovascular flow- and pressure-measuring instruments. The results were compared with those observed in a similar group of five untreated dogs. Propranolol pretreatment resulted in a small degree of additional cardiac depression at any inspired halothane concentration. The cardiac depressant effects of propranolol and halothane were found to be simply additive and therefore predictable. The presence of propranolol did not result in morbidity or mortality at any depth of halothane anaesthesia.

Animals↗
PubMed1976

Haemodynamic interactions of high-dose propranolol pretreatment and anaesthesia in the dog. II: The effects of acute arterial hypoxaemia at increasing depths of halothane anaesthesia.

Beta-adrenergic blockade may impair the normal cardiovascular response to hypoxia occurring during general anaesthesia. The haemodynamic effects of acute hypoxia, induced by a 90-s period of ventilation with nitrogen, were studied during increasing depths of halothane anaesthesia up to a maximum of 2.5% inspired halothane in dogs chronically implanted with intracardiac catheters, a left-ventricular pressure transducer and an aortic blood flow transducer. An untreated group of dogs and a group which had been treated for 3 weeks with propranolol 20 mg/kg/day were compared. The beta-blocked group had lesser cardiac output values, left-ventricular contractility indices, external left-ventricular work and peak left-ventricular power at all depths of anaesthesia except 2.5% halothane, but both groups responded to hypoxia similarly at each depth of anaesthesia. Cardiac performance was enhanced in both groups during acute hypoxia. No adverse haemodynamic effect of the combination of propranolol, halothane and hypoxia was demonstrated.

Anesthesia, General↗
PubMed1976

Haemodynamic interactions of high-dose propranolol pretreatment and anaesthesia in the dog. III: The effects of haemorrhage during halothane and trichloroethylene anaesthesia.

We have examined the haemodynamic effects of 0.8% trichloroethylene and 1% halothane anaesthesia in a control group of five dogs, chronically implanted with cardiovascular flow- and pressure-measuring apparatus and compared them with a similar group of six dogs pretreated for 3 weeks with oral propranolol (20 mg/kg/day). The effects of graded haemorrhage of 25% of the estimated blood volume and re-transfusion were studied. Cardiovascular function was satisfactory at all stages of the study except during trichloroethylene anaesthesia in the beta-blocked dogs when the response to blood loss was impaired severely. Therefore the use of trichloroethylene in the presence of propranolol may not be advisable in clinical practice.

Anesthesia, General↗
PubMed1976

Interaction of anesthesia, beta-receptor blockade, and blood loss in dogs with induced myocardial infarction.

The cardiovascular effects of halothane-nitrous oxide anesthesia, and beta-receptor blockade with either propranolol or practolol, were studied in 15 dogs in which severe myocardial infarction had been induced ten days earlier. The hemodynamic responses to blood loss amounting to 25 per cent of estimated blood volume, and its subsequent replacement, were studied before and after induction of beta-receptor blockade. In terms of cardiac output and aortic blood flow acceleration, cardiac performance in the absence of beta-blockade was markedly impaired during steady-state anesthesia, compared with corresponding values in normal dogs. Practolol (2.0 mg/kg) administered during anesthesia induced no significant circulatory change other than a 14 per cent decrease in heart rate and a 25 per cent increase in strode volum. Propranolol (0.3 mg/kg) caused a comparable reduction of heart rate, but significantly reduced cardiac output (-27 per cent), aortic blood flow acceleration (-26 per cent), and peak LV power (-19 per cent), and increased systemic vascular resistance (+49 per cent). The two drugs caused comparable shifts of the isoproterenol dose-response curve during anesthesia. Graduated blood loss during anesthesia, to a total of 25 per cent of blood volume, caused consistent circulatory changes (decreased mean arterial pressure cardiac output, peak LV power, LV minute work) that were essentially similar before and after beta-receptor blockade with either propranolol or practolol. The positive inotropic effect of calcium gluconate during halothane anesthesia was significantly reduced following either propranolol or practolol, but the hemodynamic responses to changes of systemic vascular resistance induced with acetylcholine or phenylephrine were not modified by beta-receptor blockade.

Acetylcholine↗