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Biomedical subjects

D G Shaw

Publications and source records attributed to D G Shaw.

At least 55 records · Page 3Linked to original sources

Does ethanol inhibit LH secretion in the rat?

A prevailing view among those studying neuroendocrine effects of ethanol is that acute doses suppress luteinizing hormone releasing hormone (LHRH) secretion, and consequently inhibit luteinizing hormone (LH) release in the rat. This phenomenon has not been observed in primates, and has been thought to be a species difference. The experimental procedures, however, have involved ethanol administration by oral or intragastric (ig) routes in humans and monkeys, but intraperitoneal (ip) or carotid artery injection in rats. It has also been suggested that inhibition of LH secretion by ethanol in rats is mediated by endogenous opioid peptides (EOP), because the effect can be reversed by the opiate antagonist naloxone. An alternative explanation is that ip ethanol injection might stress rats sufficiently to activate hypothalamic-pituitary-adrenocortical (H-P-A) and EOP systems that are well known to inhibit hormonal activities of the hypothalamic-pituitary-gonadal (H-P-G) axis. Presented here are preliminary results from experiments with male rats. When ethanol is administered ig, under relatively stress-free conditions, it does not inhibit LH secretion in gonadally intact or castrated males. In contrast, ip injection of the same ethanol dose (2.0 g/kg body wt) causes pronounced inhibition of LH secretion and concomitant increases in plasma prolactin (PRL) and corticosterone--indicative of a stress response. Furthermore, when ip ethanol administration is preceded by intracerebroventricular (icv) injection of a corticotropin releasing factor (CRF) antagonist (alpha-helical ovine CRF residues 9 to 41), the effects of ethanol on LH and corticosterone are blocked. These results indicate that it may be stress, rather than ethanol per se, that inhibits LHRH and LH secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Progressive non-infectious anterior vertebral fusion.

Four cases of progressive non-infectious anterior vertebral fusion are described. Three cases remain relatively asymptomatic, but one has developed spinal cord compression secondary to an acute angled kyphosis. The clinical, radiological, and pathological features are reviewed and some comparisons with the spinal changes in thalidomide embryopathy are made.

Adolescent↗

Chronic granulomatous disease mimicking Crohn's disease.

A 34-month-old boy with intermittent diarrhoea and abdominal distension from 2 months of age, a chronic microabscess of the cheek, gastric antral narrowing, and perianal abscesses containing granulomata was found at colonscopy to have extensive, noncaseating, submucosal ileal and colonic granulomata. He was initially thought to have Crohn's disease, but then developed a cervical abscess, and a diagnosis of chronic granulomatous disease was established. This is an important, although rare, differential diagnosis of chronic inflammatory bowel disease in childhood.

Abscess↗

Accuracy of imaging of the brains of newborn infants by linear-array real-time ultrasound.

Comparisons were made in 69 newborn infants of the appearance of the brain as visualised by linear-array real-time ultrasound, computerised tomography and at autopsy, in order to evaluate the accuracy of ultrasound for the detection of lesions in the brain. Ultrasound was found to give a good estimate of the presence and extent of haemorrhage into the germinal layer and ventricles, and also to be very useful for assessing the appearance of the ventricular system. Ultrasound diagnosed extradural haemorrhages but was unhelpful for identifying subarachnoid haemorrhages or lesions in the posterior fossa.

Atrophy↗

Pancuronium during mechanical ventilation speeds recovery of lungs of infants with hyaline membrane disease.

Spontaneous breathing during mechanical ventilation in newborn infants may damage the lung. To find out whether the prevalence of lesions which might be due to trauma was reduced by muscle relaxation, fifty infants who required mechanical ventilation of hyaline membrane disease were randomly assigned to treated and control groups. The treated infants were kept muscle relaxed with pancuronium bromide until they needed a FiO2 of 0.40 or less during ventilation. The mean birthweight, gestational age, age at entry to the trial, duration of intubation and ventilation, FiO2 during the acute phase of the illness, and ventilator pressures were closely comparable in the two groups. Two of twenty-six treated infants and one of twenty-four controls died. Four treated and five control infants acquired pneumothoraces and/or interstitial emphysema. The length of time that the treated infants required added oxygen was significantly less than in the control infants. All treated infants were breathing room air spontaneously by one month of age whereas seven control infants were still dependent on added oxygen, needing an average FiO2 of 0.35 to achieve a mean PaO2 of 6.5 kPa (49 mm Hg). These seven infants required added oxygen until they were 5-18 (mean 10) weeks old. Muscle relaxation during mechanical ventilation for hyaline membrane disease speeds recovery of the lungs, probably owing to a reduction in traumatic damage.

Airway Resistance↗

Relationship between the chest radiograph, regional lung function studies, exercise tolerance, and clinical condition in cystic fibrosis.

This study evaluated the accuracy of the interpretation of the chest film in delineating localised abnormalities of ventilation and perfusion, as well as the overall severity of airways obstruction, exercise tolerance, and clinical condition in children with cystic fibrosis. Radiographic findings in various regions of the chest film were compared with the functional values obtained with regional lung function tests which evaluated the arrival and disappearance of boluses of radioactive nitrogen given by inhalation and infusion. While the more severely affected areas on the chest radiograph were found to correlate with similar regions on the lung function tests, as did overall scores, errors occurred in some cases if the x-ray film alone was used as a judge of regional physiological derangement. In addition the degree of airways obstruction, the exercise tolerance on a cycle ergometer, and clinical grading, each correlated significantly with the radiographic score. We conclude that the chest radiograph is a good indicator of the overall severity of the lung disease and that it correlates well with exercise tolerance and clinical condition in cystic fibrosis.

Adolescent↗

Léri's pleonosteosis.

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Age Determination by Skeleton↗