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Biomedical subjects

A Kahn

Publications and source records attributed to A Kahn.

At least 487 records · Page 27Linked to original sources
PubMed1982

Improved rabbit brain tumor model amenable to diagnostic radiographic procedures.

The VX2 carcinoma was used to create a rabbit brain tumor model. VX2 tumors were chemically dissociated and suspended in liquid medium. Twenty-five microliters of the tumor suspension containing 3 X 10(3), 3 X 10(4), or 3 X 10(5) viable tumor cells were injected through cranial burr holes 6 mm into the right frontoparietal lobes of 17 rabbits. Fifteen of these developed histologically documented nodular intraparenchymal tumors. Tumors were demonstrable with cerebral computed tomographic scans and by cerebral angiography. The feasibility of surgical resection of lesions using the fluorescein staining technique was also demonstrated. This animal brain tumor model is suitable for neuro-oncology research focusing on imaging and therapeutic techniques.

Animals↗
PubMed1982

Effects of central apneas on transcutaneous PO2 in control subjects, siblings of victims of sudden infant death syndrome, and near miss infants.

A total of 75 polysomnograms recorded during night sessions in 25 control subjects, 25 siblings of sudden infant death syndrome victims, and 25 near miss infants were studied in order to correlate the duration of central apnea to the decrease in transcutaneous oxygen pressure (tcPO2). A total of 1,650 central apneas were recorded. The three groups of infants presented the same tendency for a lower tcPO2 in indeterminate and active sleep as in quiet sleep (P greater than .10). The apneas were not preceded by a decrease in tcPO2, but were followed by a decrease in tcPO2, directly proportional to the duration of apnea. The correlation was measured in each infant individually, and proved to be significant in all cases, and comparable in the three groups. The longest apneas (greater than ten seconds) were followed by the greatest decrease in tcPO2, and were restricted to the near miss group. Apart from this observation, the near miss and sibling infants did not show lower tcPO2 than the control subjects, at any time, during sleep.

Female↗
PubMed1982

Phenothiazines and sudden infant death syndrome.

A relationship between sudden infant death syndrome (SIDS), sleep apnea, and upper airway infections has been reported. The present observation stresses the possible influence of phenothiazine-containing medications and the occurrence of SIDS. The drug is commonly used for the treatment of infants with nasopharyngitis in Belgium and in some other European countries. In a prospective study, 52 SIDS victims, 36 near miss infants, and 175 control infants were compared for the coexistence of nasopharyngitis and phenothiazine treatment in the days preceding death or hospitalization. The incidence of nasopharyngitis was comparable in the three groups (approximately 31%), but phenothiazines were used significantly more frequently in SIDS victims (23%) and near miss infants (22%) than in control subjects (2%). It is postulated that phenothiazines, as CNS depressors, may contribute to the occurrence of SIDS.

Apnea↗
PubMed1982

Effects of obstructive sleep apneas on transcutaneous oxygen pressure in control infants, siblings of sudden infant death syndrome victims, and near miss infants: comparison with the effects of central sleep apneas.

In order to investigate the effects of obstructive sleep apneas upon transcutaneous PO2 75 polysomnograms, recorded during night sessions in 25 control infants, 25 siblings, and 25 near miss for sudden infant death syndrome (SIDS) infants were studied. These observations were compared with the decreases in transcutaneous PO2 measured during central sleep apneas in the same infants. During a total of 707.6 hours of sleep, 33 obstructive apneas and 1,650 central apneas were recorded. Obstructive apneas were seen in three control infants (three episodes), one sibling (five episodes), and six near miss for SIDS infants (25 episodes). The obstructive apneas tended to be short (less than 10 seconds). Comparatively, the central apneas were equally distributed in the three groups of infants, and only the near miss children presented apneas that lasted as long as 19 seconds. The decrease in transcutaneous PO2 was proportional to the duration of both types of apnea, but for a given duration the decrease in transcutaneous PO2 was significantly greater for the obstructive apneas than for the central apneas (with a mean difference of 7.59 +/- 0.53% PO2. It is concluded that the hypoxic effects of the obstructive apneas might have important clinical implications in infants, such as the near miss for SIDS.

Female↗
PubMed1981

The effect of water deficit on body temperature during rugby.

Sweat losses, water deficits and changes in rectal temperature were measured in 13 first-league players during a rugby match. Changes in plasma volume, serum electrolyte and blood glucose levels were also determined. Rectal temperatures were markedly elevated after the match. Both temperatures reached levels which are known to be associated with an impairment of physical, mental and psychological function, and could have caused a deterioration in performance during the second half of the match. Body temperatures were high enough to have predisposed to aggressive behaviour. Increases in rectal temperature were related to water deficit. The small volumes of fluid ingested by the players just before and during the match suggest that they are unaware of the importance of preventing dehydration. Recommendations are made to reduce the risk of hyperthermia. Glucose and electrolyte supplementation is not required just before and during rugby.

Adult↗
PubMed1981

Cyclic AMP and permeability coefficient of albumin of the isolated rat mesentery. Effects of Escherichia coli endotoxin.

We have investigated the mechanisms whereby Escherichia coli endotoxin exerts its exudative effects, by using an isolated rat mesentery placed as a separation membrane between the two compartments of a diffusion cell. The permeability coefficient of albumin (PA) can be easily computed from the equilibration rate of 125I-labeled albumin added to one compartment. E. coli endotoxin increased PA in a concentration-related manner. Direct measurements revealed an early and transient increase in cyclic AMP and prostaglandin E-immunoreactive material. These effects of endotoxin could be inhibited by indomethacin. Calcium-depleted tissues have a low PA, even though cyclic AMP levels could still be increased by endotoxin. It incubations were prolonged beyond 90 min, PA remained elevated, but prostaglandin E and cyclic AMP levels fell to control values. Similar results were observed with trypsin-treated tissues. These results suggest that transmesenteric passage of albumin is increased in the presence of endotoxin. During the earlier part of the incubation (up to 90 min), the effects could be related to a local synthesis of prostaglandin E, and are controlled by cyclic AMP and intracellular calcium levels. During longer incubations (90-280 min) mesothelial exfoliation could occur, allowing free diffusion of albumin through the remaining interstitial tissue.

Animals↗
PubMed1981

Diffuse meningocerebral angiodysplasia and adenovirus infection: an improbable relationship.

A case of diffuse meningocerebral angiodysplasia is described in which type 4 adenovirus was isolated from the brain biopsy. The pathological features were similar to those previously described by various authors (1,3,4,5) and were not indicative of an infective process. Status epilepticus in the presence of extensive arteriovenous shunting in this dysgenetic cerebromeningeal vasculature is probably responsible for the extensive necrosis observed in the cortex and white matter.

Adenoviridae Infections↗
PubMed1981

Controlled fall in natremia in hypertonic dehydration: possible avoidance of rehydration seizures.

This prospective study comprises 40 infants with severe hypernatremic dehydration due to gastroenteritis. During the first 24h, natremia was closely monitored and infusion rates were adjusted so as to keep the rate of fall in natremia below 0.5 mEq/l/h. This could be achieved by giving a 70 mEq/l Na solution at the rate of 120 ml/kg/24 h. Rehydration was uneventful in all cases, and no convulsions were observed.

Dehydration↗
PubMed1981

Involvement of prostaglandins in the local action of endotoxin.

Endotoxin from Gram-negative bacteria increases the permeability coefficient of albumin in isolated rat mesenteries used as a separating membrane between the two halves of a diffusion cell. Endotoxin also promotes cyclic AMP accumulation in similar mesenteric sheets. These effects are dose-related, and are inhibited by indomethacin. As shown by direct assay, Prostaglandin E-immunoreactive material is synthesized in the presence of endotoxin and is responsible for the increase in albumin permeability and for the increase in cyclic AMP.

Albumins↗