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L Schechter

Publications and source records attributed to L Schechter.

11 recordsLinked to original sources
PubMed1996

[3H]5-hydroxytryptamine labels the agonist high affinity state of the cloned rat 5-HT4 receptor.

We have used the cloned rat 5-HT4 receptor, and determined that the single protein product produced is able to bind both [3H]5-HT and [3H]GR113808 ([1-[(2-methyl sulphonyl) amino] ethyl-4-piperidinyl] methyl-1-methyl-1H-indole-3-carboxylate) with high affinity. The affinities of agonists for the [3H]5-HT (agonist)-labelled receptor were significantly higher than for the [3H]GR113808 (antagonist)-labelled receptor. Furthermore, [3H]5-HT binding was reduced by addition of guanyl nucleotides. These results strongly support the hypothesis that the 5-HT4 receptor displays two interconvertible affinity states (high and low) for agonists, characteristic of many G protein coupled receptors. [3H]5-HT, at the concentration employed, therefore labels the agonist high affinity state of the 5-HT4 receptor in systems in which high densities of this receptor are found.

Affinity Labels↗
PubMed1987

Intermittent claudication associated with cancer--case studies.

Cancer was diagnosed in 15 patients among 300 consecutive patients with intermittent claudication. The cancer-associated claudication is characterized by a more accelerated course of claudication, more often requires vascular surgery, and moreover, the lasting relief of claudication depends upon the efficiency of cancer therapy. It is the authors' impression that cancer-associated claudication is predetermined by atherosclerosis and aggravated by cancer through the chronic hypercoagulability state secondary to neoplasm. The clinical picture is characterized by rapid progression, with the frequent necessity of vascular surgery for limb salvage and a higher incidence of graft occlusion. Awareness of this possibility of hidden malignancy may be related to the clinical picture of hemodynamic deterioration of the underlying arterial insufficiency. A high index of suspicion leads to earlier diagnosis of neoplasm. Effective oncologic therapy will often bring the symptomatic relief of ischemic symptoms in the lower extremities. This report indicates that associated neoplasm has a more vicious course of the underlying arterial insufficiency and intermittent claudication.

Adenocarcinoma↗
PubMed1987

Subclavian vein stenosis as a complication of subclavian catheterization for hemodialysis.

Thirteen patients had placement of a subclavian vein catheter for temporary vascular access for hemodialysis. Peripheral venography was performed within two to six weeks of catheter placement. Forty-six percent (six of 13 patients) developed subclavian vein narrowing, which resolved in two patients. The duration of catheter placement had no impact on the incidence of this complication. Subclavian vein catheterization can frequently lead to subclavian vein stenosis, which often will resolve spontaneously. Consideration should be given to placement of subclavian lines on the contralateral side of a planned permanent vascular access.

Catheterization↗
PubMed1981

Nondegradation of fecal cholesterol in subjects at high risk for cancer of the large intestine.

In previous studies subjects with familial polyposis, the autosomal dominant disease leading to colon cancer, excreted higher levels of fecal cholesterol than normal subjects, with decreased conversion to degradation products. Findings suggested fecal cholesterol degradation as a marker of hereditary predisposition to colon cancer. Current measurements now have shown that affected individuals and asymptomatic progeny in a second population group with inherited predisposition to colon cancer are low converters of fecal cholesterol. The latter group consisted of highly colon cancer prone families without polyposis, in which patterns of inheritance similar to the autosomal dominant pattern of familial polyposis were observed. 24-h stool collections were obtained from 72 subjects who consumed mixed western diets. Mean percent degradation of fecal cholesterol to coprostanol, coprostanone, cholestanol, and cholestanone revealed significant decreases in fecal cholesterol conversion in affected and asymptomatic subjects in colon cancer prone families without polyposis (P < 0.001) compared to controls. This is in addition to those with familial polyposis (P < 0.001), and extends this marker of colon cancer susceptibility to a second population group with hereditary predisposition to colonic neoplasia.

Cholesterol↗
PubMedDate not supplied

Measured total energy requirements of adult patients with burns.

Adequate nutritional support is a primary concern in the treatment of patients with burns. Traditionally dietitians estimated energy requirements with the use of multifactorial equations that took into account anthropometric variables and burn severity. Recently, however, the availability of portable metabolic carts has reduced the need for dietitians to rely on predicted requirements. The use of metabolic carts, however, likely causes the underestimation of energy requirements because the carts do not always accurately measure the effects of surgery, dressing changes, and other related treatments. The aim of the current study was to determine the difference between resting energy expenditure and total daily energy expenditure. Seven adult patients whose burns ranged from 18% to 80% of their total body surface areas were studied. Total daily energy expenditure was measured with doubly labeled water, and resting energy expenditure was measured by studying respiratory gas exchange in the fed and fasted states. Total daily energy expenditure averaged 106% +/- 11% of average resting energy expenditure. Within the limits of the small data set studied, energy requirements could be measured with the use of the resting metabolic rate by allowing for an increase of 5% to 15% for nonrest activities and treatments.

Adult↗
PubMedDate not supplied

The main features of central 5-HT1 receptors.

The 5-HT1 receptor family comprises five different pharmacologic subtypes, designated 5-HT1A, 5-HT1B, 5-HT1C, 5-HT1D, and 5-HT1E, whose common property is to bind 5-HT with nanomolar affinity. Recent investigations with molecular biology approaches led to the cloning and sequencing of 5-HT1A receptors in the rat and in the human, and of the 5-HT1C receptor in the rat. Although the 5-HT1A and 5-HT1C protein binding subunits exhibit the same structure with seven hydrophobic transmembrane domains, an extracellular N terminal and an intracellular C tail, their respective amino-acid sequences are markedly different. Indeed, a higher degree of sequence homology is found between the 5-HT1C and 5-HT2 receptors than between the former and 5-HT1A receptors, suggesting that the 5-HT1C subtype in fact belongs to the 5-HT2 class of central 5-HT receptors. All other 5-HT1 receptor subtypes are negatively coupled to adenylyl cyclase, whereas the 5-HT1C subtype, like 5-HT2 receptors, is positively coupled to phospholipase C. The respective regional distributions and regulatory properties, as well as pending questions regarding the ultrastructural localization, synthesis, mutual interactions, and axonal flow of 5-HT1 receptor subtypes, are also discussed.

Animals↗