Biomedical subjects
Publications and source records attributed to J M Stein.
Sixteen panic patients and fifteen normal controls performed submaximal exercise testing on a bicycle ergometer. Only one patient subject panicked. Biochemical, physiological, and psychological data showed similar exercise tolerance in both patients and controls. Exercise-induced distress and lactate increment do not appear to cause panic attacks.
Severe occlusal destruction, whether it results from attrition, abrasion, or erosion, must be met with definitive diagnosis and treatment. This case report illustrates the step-by-step diagnosis and treatment of a patient with severe occlusal wear. Restoration of a functional occlusion and esthetics involved endodontic treatment, reestablishment of the vertical dimension of occlusion, osseous periodontal surgery, and placement of single-tooth cast glass-ceramic crowns.
A method for the quantification of membrane lipids by acetylation with [3H]acetic anhydride is described. A standard lipid, labelled with 14C or 32P, is added to the sample and is simultaneously acetylated. The 3H/14C or 3H/32P ratios obtained in the acetylated lipids are proportional to the initial lipid concentration. The method has been used to quantify cholesterol, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in amounts between 2 and 10 nmol.
During sublytic complement attack on human neutrophils, plasma-membrane vesicles are shed from the cell surface as a cell-protection mechanism. By using surface-iodinated neutrophils it was found that less than 2% of surface label was recovered in shed vesicles under conditions where 40% of complement component C9 was shed. SDS/PAGE of 125I-labelled shed vesicles and plasma membranes showed differences in iodination pattern, demonstrating the sorting of membrane proteins into the shed vesicles. Analysis of 32P-labelled phospholipids after labeling of neutrophils with [32P]Pi before sublytic complement attack showed the presence of phosphatidic acid, phosphatidylcholine, phosphatidyl-ethanolamine, phosphatidylinositol and polyphosphoinositides in shed vesicles. Quantitative analysis using [3H]acetic anhydride-labelling method showed that the molar proportions of phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine and sphingomyelin were the same in shed vesicles as in plasma membranes. In contrast, the molar proportions of cholesterol and diacylglycerol relative to sphingomyelin were almost twice those found in plasma membranes. The data demonstrate the existence of protein and lipid sorting mechanisms during the formation of shed vesicles when neutrophils are subject to sublytic complement attack. The term 'ectocytosis' is proposed to describe triggered shedding of right-side-out membrane vesicles from the surface of eukaryotic cells.
1. The irradiation-inactivation procedure was used to study changes in the state of association of the protein components of adenylate cyclase in intact rat liver plasma membranes by measurement of alterations in the target size determined from the catalytic activity of the enzyme. 2. A decrease in target size at 30 degrees C in response to p[NH]ppG (guanosine 5'-[betagamma-imido]triphosphate) or GTP was demonstrated, which we take to reflect the dissociation of a regulatory subunit. The effect of GTP is potentiated by glucagon. This effect is not observed at 0 degrees C. 3. An increase in target size was observed in response to glucagon in the absence of guanine nucleotides, which we take to reflect the association of glucagon receptor with adenylate cyclase. 4. We propose a model for the activation of adenylate cyclase by glucagon in which the binding of the hormone to its receptor causes an initial association of the receptor with the catalytic unit of the enzyme and a regulatory subunit to form a ternary complex. The subsequent activation of the adenylate cyclase results from the dissociation of the ternary complex to leave a free catalytic unit in the activated state. This dissociation requires the binding of a guanine nucleotide to the regulatory subunit. 5. The effects of variation of temperature on the activation of adenylate cyclase by glucagon and guanine nucleotides were examined and are discussed in relation to the irradiation-activation data. 6. The effectiveness of hormones, guanine nucleotides and combinations of hormone and guanine nucleotides as activators of adenylate cyclase in both rat liver and rat fat-cell plasma membranes was studied and the results are discussed in relation to the model proposed, which is also considered in relation to the observations published by other workers.
Circumferential burn injuries can produce severe ischemia in the underlying muscles by producing compartmental compression. The latter requires prompt decompression, but it is often difficult to diagnose. A simple, rapid, and accurate technique for the direct measurement of compartmental pressure is described. It may be used to determine the need for decompressive escharotomy or fasciotomy, and to intraoperatively assess its adequacy.
Reduction of bacterial dose and support of host defense mechanisms are paramount in the prevention of infections. When infection is established, aggressive search for its cause and extent is necessary. Vigorous nonoperative (antibiotic, nutritional) and operative therapies are needed to eradicate infection and to salvage life and limb.
Explore the source record for details and available documents.
Para-chloroamphetamine (PCA) produces short-term decreases in eating and drinking. PCA also chronically decreases brain serotonin concentration following a single peripheral injection. The present investigation assessed short- and long-term effects of PCA on ingestive behavior and body weight in greater detail. Following an adaptation period, PCA, 0.0, 1.0, 2.0, 5.0 and 10.0 mg/kg, were administered IP, to free feeding rats. A decrease in food and water consumption was observed during the 0--24 hr postinjection period. During the 24--48 hr period, water consumption was significantly increased compared to baseline. Food intakes during this same period returned to baseline levels. No long-term effects on ingestive behavior or body weight were seen during the following 30 days.
Preliminary results indicated enhanced serotonin turnover in the lateral hypothalamus of 24 hr food deprived rats as compared to non-deprived rats. In the present study, the periods of food deprivation were extended in ordered that the effects of 0. 24, 48 and 72 hr of food deprivation on serotonin turnover could be measured. One hr following an infusion of 3H-5-hydroxytryptamine the lateral hypothalamus was perfused with physiological bacteriostatic saline for 40 min. Samples of perfusate, which corresponds to 75--90 min post-infusion, were analyzed by thin layer chromatography for estimation of 3H-labelled precursor and metabolites. The results indicate that serotonin turnover is enhanced as a function of hours of food deprivation.
One hr following an infusion of 3H-L-tryptophan, the lateral hypothalamus was perfused with physiological bacteriostatic saline for 40 min. Samples of perfusate, which corresponded to 75--90 min post-infusion, were analyzed by thin layer chromatography for estimation of 3H-labelled L-tryptophan, 5-hydroxytryptophan and 5-hydroxytryptamine. The results indicate that tryptophan uptake and serotonin synthesis are enhanced as a function of hours of food deprivation.
The distribution of eating, drinking and body weight changes during the 24 hr day were examined following brain 5-HT depletion with p-chloroamphetamine (PCA). Following a baseline period, measurements of food and water intakes and body weights were recorded 1, 2, 3, 6, 12, 20 and 24 hr following PCA, 5.0 mg/kg, or saline. Other animals were pretreated with fluoxetine, 10.0 mg/kg, prior to either PCA or saline in an attempt to block the PCA effects. The results indicate acute hypophagia, hypodipsia, and body weight losses. These decreases were not influenced by the time of day when PCA was administered. Pretreatment with fluoxetine enhanced rather than blocked these effects. No long term changes in ingestive behavior were seen. These results are discussed with respect to the possible role of 5-HT in the control of ingestive behavior.
One hour following an infusion of 3H-5-hydroxytryptamine, animals were injected with either 15 mg/kg imipramine hydrochloride or 0.9% NaCl and then the lateral hypothalamus was perfused for 40 min. Samples of perfusate were analyzed by thin layer chromatography for estimation of 3H-labelled 5-hydroxytryptamine and metabolites. The results indicate that impramine hydrochloride 15 mg/kg decreases serotonin release and turnover in the lateral hypothalamus.
The lateral cerebroventricle was perfused using two different labelling procedures in three separate experiments on 5-hydroxytryptamine metabolism. The sensitivity of 5-hydroxytryptamine metabolism to various drugs was subsequently determined. The results demonstrate that two serotonin reuptake blockers, imipramine and fluoxetine, increase the efflux of 3h-5-hydroxytryptamine into the ventricle without affecting the efflux of 3H-5-hydroxyindoleacetic acid. BL-3912 A, a drug with weak serotonin agonist activity, also increased the efflux of 3H-5-hydroxytryptamine into the ventricle.
Explore the source record for details and available documents.
The advisability of transporting severely burned civilian patients to a definitive burn-care facility during the first hours following injury is discussed and methods providing safe transport for 353 civilian burn patients are described. Feasibility of and methods for transporting patients over various distances are outlined and the problems of jet transportation presented. Adequate communication between referring and receiving physicians is imperative, as are adequate preparation before evacuation and maintenance of intravenous fluid resuscitation, intake and output records, and sterile technique during transport.
Explore the source record for details and available documents.
The effects of para-chlorophenylalanine (PCPA) on the ingestive behavior of rats offered a choice between ethanol (3%) and water, saccharin (0.125%) and water, or water alone were examined. Following a baseline period three saline or PCPA injections, 80 mg/kg, were administered. Decreases in both ethanol and saccharin intakes were observed. Increases in water intake occurred in the ethanol group without a change in total fluid intake. Increases in water intake did not occur in the saccharin group and these animals displayed decreases in total fluid intake. Water intake in the nonchoice group was unaffected. There were no changes in food intake associated with any of these effects. The data demonstrate that decreases in intakes following PCPA are not specific to ethanol solutions.