PubMed Health⌕ Search

Biomedical subjects

S L Cohen

Publications and source records attributed to S L Cohen.

At least 91 records · Page 5Linked to original sources
PubMed1981

Traumatic hepatic artery/hepatic vein fistula.

Traumatic hepatic artery/hepatic vein fistula was experienced in a 3 year-old boy. This hepatic arteriovenous fistula was diagnosed by a selective angiography of the hepatic artery. To prevent heart failure and pulmonary embolism developing, hepatic artery ligation was carried out. The postoperative course was uneventful and the patient was discharged without any sequelae. This paper summarizes our experience of a case with traumatic hepatic arteriovenous fistula and the treatment of hepatic artery ligation is discussed.

Arteriovenous Fistula↗
PubMed1981

Intravascular mixed venous oxygen tension monitoring. An analysis of electrode performance in 100 patients.

A lengthened umbilical artery catheter incorporating an oxygen electrode (Searle) was flow-guided to the pulmonary artery in 48 out of 62 attempts (77.4%). In the last 70 catheters used, electrode performance was evaluated over a total of 3687 h by comparison with an ABL2 (Radiometer) blood-gas analyser; 654 comparisons were made, of which 255 resulted in recalibration of the electrode output. When sampling intervals were within 6 h, in more than 80% of the comparisons the difference between in vivo and in vitro measurement was within +/- 0.4 kPa (+/- 3 mm Hg). Twenty-four electrodes were removed sooner than clinically indicated (mean useful life 48.5 h) because of failure of oxygen or pressure measurements.

Blood Gas Analysis↗
PubMed1981

The effects of brief-stimulus presentations in fixed-ratio second-order schedules.

Pigeons' responses were reinforced according to a three-component multiple schedule. In Component 1, key pecks produced food according to a fixed-ratio second-order schedule with fixed-ratio units. Here, a fixed number of fixed-ratio units produced food, and the brief stimulus terminating each unit also accompanied food. Responses in Component 2 produced food on an identical schedule except that the brief stimulus was not paired with food. Component 3 contained a simple fixed-ratio schedule whose response requirement equaled that of Components 1 and 2. Across conditions the size of the fixed-ratio unit (five, ten, twenty, forty, and eighty responses) and the total number of responses per reinforcement were parametrically manipulated. The highest response rates and shortest preratio pauses were observed in Component 3 (no brief stimulus). The lowest rates and longest pauses were found in the component with paired brief-stimulus presentations, indicating that the food-paired brief stimulus suppressed responding. The suppressive effects were greatest when the fixed-ratio units were small (e.g., fixed-ratio 5) and the total fixed-ratio requirement was large (e.g., fixed-ratio 160). Under no conditions did the paired brief stimulus facilitate responding. The nonpaired brief stimulus also suppressed responding but to a lesser extent. The suppressive effects of nonpaired brief stimuli were greatest when the fixed-ratio units were small and the total response requirement was large. These data suggest that the suppressive effects of the brief stimuli may have masked the conditioned-reinforcing effects reported in other studies, and that conditions that maximize suppression in second-order schedules involve the use of fixed-ratio schedule units and the presentation of many brief stimuli per reinforcer.

Journal Article↗
PubMed1980

The mechanism of hyperlipidaemia in nephrotic syndrome--role of low albumin and the LCAT reaction.

Diminished autologous LCAT activity was found in patients with proteinuria. This was due to substrate limitation and albumin appeared the most likely limiting factors. It is suggested that low albumin can contribute to the hyperlipidaemia of nephrotic syndrome through its role on the LCAT reaction. Evidence of the ability of triglyceride to enhance homologous LCAT activity was also noted.

Adolescent↗
PubMed1980

Osteochondritis dissecans of the hip: a rare disorder in the aged (case report).

Osteochondritis dessicans of the hip is rare in comparison with occurrence of the disease in other joints. Only about 50 cases have been reported. The literature is reviewed, and a new case is presented. The patients was a 94-year-old Spanish American War Veteran who was unusally active and in good health until the onset of osteochondritis dissecans in the right hip (classic clinical and roentgenologic findings). Despite his advanced age and the severe arthritic changes, under conservative therapy he gradually regained a suprising degree of mobility in the affected hip.

Aged↗
PubMed1979

Separating the reinforcing and discriminative properties of brief-stimulus presentations in second-order schedules.

Pigeons' responses were maintained under multiple schedules to study properties of briefly presented stimuli. Responses in one component produced food according to a second-order schedule with fixed-interval components in which food or a brief stimulus occurred with equal probability. In the second component responses produced only the brief stimulus under a fixed-ratio schedule. Under various conditions the brief stimulus in the first component was (a) paired with food, (b) not paired with food, (c) partially omitted, or (d) scheduled simultaneously with the second-order schedule under an independent variable-interval schedule. Paired and nonpaired brief stimuli maintained similar response patterning in the second-order schedule. However, only paired stimuli maintained responses in the second component. The data suggest that nonpaired brief stimuli engender response patterning in second-order schedules as a result of their discriminative properties. When the stimulus is paired with food, these discriminative properties sometime mask a reinforcement effect, and no change in response patterning is observed. When the discriminative properties of the brief stimulus are absent, the reinforcing effects of pairing the brief stimulus with food may be observed.

Animals↗
PubMed1979

Cephradine-induced interstitial nephritis.

A patient developed acute interstitial nephritis following cephradine administration. The clinical illness preceding the interstitial nephritis and the eosinophilia in peripheral blood suggested an allergic reaction. Immunological studies demonstrated an allergy to cephradine and penicillins which was IgG2-mediated. It is probable, therefore, that allergy to cephradine caused the renal lesion from which there was full clinical and biochemical recovery.

Adult↗
PubMed1978

Continuous monitoring of mixed venous oxygen tension (PvO2) in cardiorespiratory disorders.

The development of a miniature polarographic electrode mounted in the tip of a double-lumen plastic catheter has made possible continuous in-vivo monitoring of oxygen tension. Inexpensive catheters of this type have already proved of value as a means of continuously monitoring arterial oxygen tension in the newborn. In 25 patients with acute respiratory failure we found that these catheters could be safely and easily flow-guided into the pulmonary artery. In this way continuous recordings of mixed venous oxygen tension (PvO2) could be made for a period of several days. In our experience a sustained fall of PvO2 below 40 mm Hg proved to be a reliable indicator of respiratory or cardiac deterioration not always obvious by observation. In the patients described, falls of this order were seen after reductions in inspired oxygen concentration, in acute respiratory failure, in accidental underventilation, and in hypovolaemia and cardiac arrythmias. In some very ill patients routine nursing care involving movement of the patient caused pronounced falls of PvO2. Although electrode drift was an occasional problem, this could be checked by intermittent blood-sampling and recalibration if necessary.

Aged↗
PubMed1978

The preparation of pregnancy urine for an estrogen profile.

A method is described for purifying the estrogen content of pregnancy urine with little loss of the labile estrogens. The procedure makes use of the initial 50-fold purification effected by their precipitation whith ammonium sulphate, with simultaneous elimination of most urinary corticosteroids and 50--60% of urinary ketosteroids. It also employs the antioxident ascorbic acid as an additive in most stages of the procedure. The mild organic-solvent-HIO partition system of Brown is used for separating the strongly polar, 2including all "labile" estrogens, and of the weakly polar estrogens, from neutral steroids. The remaining neutral steroid still interfering with the assays were removed by an ascorbic acid treated ion exchange resin (AG 1). The final residues were revealed by mass-spectroscopy to consist almost solely of estrogens. Gas-liquid chromatography in which just 2 chromatograms are required yields a total of 12 "estrogen" peaks (for 12 estrogens which are excreted in amounts greater than 0.1 mg/day) in normal pregnancy urine, including all the known labile estrogens. Identification as estrogen for all but a few minor peaks of the gas chromatogram was obtained by mass-spectroscopy. The practical significance of the method lies in the fact that some labile estrogens are much more important in the estrogen metabolism of pregnant and nonpregnant women than heretofore generally thought.

Ammonium Sulfate↗
PubMed1978

The possible adverse effect of propranolol on the fetus in pregnancies complicated by severe hypertension.

A retrospective study is presented of the effect of propranolol on fetal outcome in pregnancies complicated by maternal hypertension. In nine pregnancies in which propranolol was given to markedly hypertensive women (diastolic blood pressure over 105 mm Hg) the fetal outcome was worse than in 15 patients using other hypotensive agents. The probability of fetal or neonatal death was related to the amount of proteinuria and the presence of parenchymal renal disease but was also significantly higher when the mother had been treated with propranolol. Experimental evidence suggests that beta-adrenergic blockade is harmful to the hypoxic fetus, for these reasons the use of propranolol in hypertensive pregnancies complicated by placental insufficiency may be contraindicated unless there is no satisfactory alternative.

Birth Weight↗