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Biomedical subjects

C Hall

Publications and source records attributed to C Hall.

389 records · Page 22Linked to original sources

Neuropsychological functioning after treatment for hematological malignancies in childhood, including autologous bone marrow transplantation.

Neuropsychological functioning and academic achievement were assessed in 26 patients 2-10 years after autologous bone marrow transplantation (ABMT) for childhood hematological malignancies. Serial tests of general intelligence before and after ABMT were supplemented with a cross-sectional study of neuropsychological functioning. Test results for general intelligence were in the normal range and mainly unaffected over time, but below average performance in specific neuropsychological tests was found in a higher number of children than expected, especially for the variables "Strategies," "Attention," and "Memory." All school children were in regular classes; 5/15 obtained extra tutorial help and two of them had major learning difficulties. Eight young adults reported normal academic achievement. Low age at diagnosis and long time since ABMT correlated significantly with lower test results on general intelligence and "Attention," and high intensity of treatment directed to the central nervous system correlated with more learning difficulties as assessed by teachers. Children with identified problems in school were offered educational counseling based on their test profiles. To enable such counseling, it is suggested that both IQ tests and neuropsychological tests on memory and attention be included in follow-up programs for children who have received high-intensity cancer treatment.

Adolescent↗

Is there a pericardial restriction to the cardiac secretion of atrial natriuretic factor?

Atrial natriuretic factor (ANF) is secreted from atrial myocytes in response to increased atrial wall stress caused by increased transmural pressure. This study investigates whether the presence of an intact pericardium restricts the ANF secretory response to an increment in left atrial pressure caused by acute aortic constriction in anaesthetized open-chest pigs. The rise in ANF plasma concentration secondary to constriction was higher when the pericardium had been surgically opened than when it was left intact. Furthermore, an opened pericardium led to a larger increase during constriction in left atrial diameter as measured by sonomicrometry. The results suggest that the intact pericardium restricts the cardiac release of ANF secondary to aortic constriction, probably by restricting left atrial dilatation.

Animals↗

Parenteral nutrition and nutritional support in Veterans Administration Medical Centers.

Two surveys eliciting information regarding parenteral nutrition and nutritional support in Veterans Administration Medical Centers were performed in 1981. Of 133 answering Veterans Administration Medical Centers, 45% had nutritional support teams. Two-thirds of these nutritional support groups were reported to be active. If an attempt to assess the quality of these programs is made by establishing performance criteria, then 23 medical centers have active and well-functioning nutritional support programs.

Hospitals, Veterans↗

Pathology of rotavirus infection in suckling mice: A study by conventional histology, immunofluorescence, ultrathin sections, and scanning electron microscopy.

Pathologic changes induced in the small intestine of suckling mice by rotavirus infection were studied by conventional histology, immunofluorescence, scanning electron microscopy, and electron microscopy of ultrathin sections. Infection could be detected within 24 hours in a few mice, but after 2 days it was well established. Swollen, often vacuolated infected cells were found on the sides and tips of villi from which they rapidly became detached; microvilli showed variable irregularity. Immature enterocytes from crypts replaced lost infected cells. By the tenth day very few infected cells could still be found. Both tubular structures and spherical particles occurred in the infected cells. Only tubular structures were found in nuclei.

Animals↗

Experimental laryngeal reinnervation by phrenic nerve implantation into the posterior cricoarytenoid muscle.

Under general anaesthesia, 5 dogs underwent sectioning of the right recurrent nerve followed by implantation of the phrenic nerve into the posterior cricoarytenoid (PCA) muscle. Some 6-7 months later the dogs were sacrificed after registration of vocal cord motility. Still photographs and movie film of the larynx were taken during quiet and forced respiration and at electrical stimulation of the implanted phrenic nerve. The PCA and vocal muscles were removed for histochemical studies. We found practically no abductory movement of the vocal cord on the reinnervated side, either during quiet or forced respiration. During forced inspiration there was, however, a slight medial bowing of the right vocal cord. At electrical stimulation there was a sphincteric movement of the entire larynx. Histochemistry showed a reinnervation picture of both the PCA and the vocal muscles on the experimental side. The conclusion drawn from this study is that axonal escape, probably from the implantation site, results in an unwanted reinnervation of laryngeal adductor muscles, which neutralize the abducting effect of the PCA muscle during inspiration. This method therefore does not seem to be suitable as a treatment alternative for bilateral recurrent nerve paralysis.

Adenosine Triphosphatases↗

Blood flow measurement in PTFE grafts.

In vascular surgery peroperative control of the result of reconstruction is essential. PTFE-grafts have been known to be "resistant" to flow registration with electromagnetic flowmetry because of the electrical isolation. Similarly, intraoperative Doppler registration has been impossible because of the attenuation of the ultrasound in the graft wall. The leading disturbances are obviously caused by air in the graft material and are not caused by the material itself. By squeezing the graft carefully between the thumb and forefinger, blood slowly penetrates the wall colouring it red. The squeezing is performed intermittently to avoid occlusion of the graft. Excellent flow registration is obtained after less than 2 min squeezing of the thin walled graft, while at least 5 min squeezing is necessary to obtain signals from thick walled grafts. To obtain satisfactory ultrasound signals more squeezing is necessary.

Animals↗

Disposition, metabolism, and pharmacodynamics of labetalol in adult sheep.

Labetalol causes significant maternal and fetal metabolic effects in pregnant sheep (Yeleswaram et al., J. Pharmacol. Exp. Ther. 262, 683-691 (1992)). This study was undertaken to investigate the contribution of skeletal muscles in the development of metabolic acidosis induced by labetalol and to explore the involvement of active metabolite(s) using conscious, chronically instrumented adult nonpregnant ewes. Following a 100 mg iv bolus, the disposition of labetalol was similar to that observed in pregnant sheep. The effects of labetalol included hypotension, reflex tachycardia, a significant increase in femoral blood flow, hyperglycemia, lactic acidosis, and increased hind limb oxygen consumption. The arteriovenous flux of labetalol, glucose, lactate, and oxygen across the hindlimb was calculated using the Fick principle. The net output of lactate from the hindquarter over 12 hr following drug administration was calculated to be 6.25 +/- 1.35 g (0.07 +/- 0.015 mol). Glucuronidation, sulfation, and oxidative metabolism of labetalol were studied using urine and bile samples. The cumulative urinary excretion of labetalol as unchanged drug, glucuronide and sulfate was found to be 1.61 +/- 0.3, 11.46 +/- 2.83, and 1.47 +/- 0.74% of the dose, respectively. Using GC-mass selective detection, the presence of 3-amino-1-phenylbutane (3-APB), a close congener of amphetamine, in urine and bile samples was established. The cumulative excretion of 3-APB in urine represents 0.044 +/- 0.016% of the dose. Pharmacokinetic analysis shows the apparent elimination half-life of the metabolite to be 13.5 +/- 3.8 min. Conjugates of 3-APB were also found in the bile and urine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗