What role will composite resins have (vs. porcelain) in the future?
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Composite Resins↗
Biomedical subjects
S Katz
Publications and source records attributed to S Katz.
Isolated gastric varices due to spontaneous splenic vein thrombosis.
Isolated bleeding gastric varices due to a spontaneous idiopathic thrombosis of the splenic vein was found to be the cause of obscure, painless recurrent bleeding in our patient. The diagnosis of spontaneous splenic vein thrombosis should be considered in the presence of gastrointestinal bleeding with unexplained splenomegaly. Prominent gastric folds may be the only barium contrast or endoscopic finding often lacking esophageal varices. Arteriography is essential in demonstrating an obstructed splenic vein. Splenectomy is the treatment of choice of "left-sided" portal hypertension.
Gastrointestinal Hemorrhage↗
Pulmonary venoocclusive disease in pregnancy.
A 23-year-old woman in her 27th week of gestation presented with clinical findings of progressive pulmonary hypertension. After cardiac catheterization she went into labor and was delivered by cesarean section. She died shortly thereafter from right heart failure. Pulmonary venoocclusive disease was found at autopsy. Hemodynamic changes during pregnancy, labor, delivery, and the postpartum period may have contributed to her deterioration and death. This is the first description of pulmonary venoocclusive disease in pregnancy.
Adult↗
Azidocalmodulin derivatives. Activation of, and binding to, three target proteins: aorta myosin light-chain kinase, erythrocyte (Mg2+ + Ca2+)-dependent ATPase and cardiac sarcoplasmic-reticulum kinase.
Different azidocalmodulin derivatives were synthesized by modification of either one carboxylic acid group or one or several arginine residues and their binding and activation capacity investigated in three target enzyme systems. The systems studied were smooth-muscle myosin light-chain kinase, cardiac sarcoplasmic-reticulum kinase and erythrocyte (Mg2+ + Ca2+)-dependent ATPase. The results indicated that the activation ability of each calmodulin derivative was different depending on the system studied. Binding studies carried out by the displacement of 125I-calmodulin indicated that the monosubstitutions did not greatly alter the apparent Kd of calmodulin for the enzymes but that the modification of four arginine residues caused a 4-8-fold increase in the apparent Kd in all systems. These results have shown that azidocalmodulin derivatives may have different degrees of usefulness in the study of calmodulin target proteins in different systems, with the behaviour of the derivatives not predictable on the basis of the nature (soluble or membrane-bound) or the type (ATPase or kinase) of enzyme system to be investigated. However, the monosubstituted calmodulin and, in particular, the carboxylic acid-group-modified derivative (where the modification was statistically dispersed over the protein chain) are good candidates for photolabelling calmodulin-binding proteins.
Amino Acids↗
A new, informal glimpse of Dr. Frederick Banting.
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Canada↗
Active life expectancy.
This study was designed to demonstrate the feasibility of forecasting functional health for the elderly. Using life-table techniques, we analyzed the expected remaining years of functional well-being, in terms of the activities of daily living, for noninstitutionalized elderly people living in Massachusetts in 1974. The expected years, or active life expectancy, showed a decrease, from 10 years for those aged 65 to 70 years to 2.9 for those 85 or older. Active life expectancy was shorter for the poor than for others, and women had a longer average duration of expected dependence than men. The measure of active life expectancy provides important information about health at a given population level, in terms other than death. This information can be used for actuarial purposes in planning and policy making. It is also useful in identifying high-risk populations for which preventive health care and medical care can compress morbidity during the last years of life.
Activities of Daily Living↗
Regulation of calcium accumulation and efflux from platelet vesicles. Possible role for cyclic-AMP-dependent phosphorylation and calmodulin.
Calcium-accumulating vesicles were isolated by differential centrifugation of sonicated platelets. Such vesicles exhibit a (Ca2+ + Mg2+)-ATPase activity of about 10 nmol (min . mg)-1 and an ATP-dependent Ca2+ uptake of about 10 nmol (min . mg)-1. When incubated in the presence of Mg[gamma-32P]ATP, the pump is phosphorylated and the acyl phosphate bond is sensitive to hydroxylamine. The [32P]phosphate-labeled Ca2+ pump exhibits a subunit molecular weight of 120 000 when analyzed by lithium dodecyl sulfate-polyacrylamide gel electrophoresis. Platelet calcium-accumulating vesicles contain a 23 kDa membrane protein that is phosphorylatable by the catalytic subunit of cAMP-dependent protein kinase but not by protein kinase C. This phosphate acceptor is not phosphorylated when the vesicles are incubated in the presence of either Ca2+ or Ca2+ plus calmodulin. The latter protein is bound to the vesicles and represents 0.5% of the proteins present in the membrane fraction. Binding of 125I-labeled calmodulin to this membrane fraction was of high affinity (16 nM), and the use of an overlay technique revealed four major calmodulin-binding proteins in the platelet cytosol (Mr = 94 000, 87 000, 60 000 and 43 000). Some minor calmodulin-binding proteins were enriched in the membrane fractions (Mr = 69 000, 57 000, 39 000 and 37 000). When the vesicles are phosphorylated in the presence of MgATP and of the catalytic subunit of cAMP-dependent protein kinase, the rate of Ca2+ uptake is essentially unaltered, while the Ca2+ capacity is diminished as a consequence of a doubling in the rate of Ca2+ efflux. Therefore, the inhibitory effect of cAMP on platelet function cannot be explained in such simple terms as an increased rate of Ca2+ removal from the cytosol. Calmodulin, on the other hand, was observed to have no effect on the initial rate of calcium efflux when added either in the absence or in the presence of the catalytic subunit of the cyclic AMP-dependent protein kinase, nor did the addition of 0.5 microM calmodulin result in increased levels of vesicle phosphorylation.
Adenosine Triphosphate↗
Separation and quantitation of oxypurines by isocratic high-pressure liquid chromatography: application to xanthinuria and the Lesch-Nyhan syndrome.
An isocratic HPLC technique has been developed for the separation and measurement of urine and plasma oxypurines in a patient with xanthinuria. The case history and laboratory data are presented. Xanthine excretion was 172 mg/g creatinine and hypoxanthine was 45 mg/g creatinine. Uric acid was too small to be measured but uricase determination showed only 3 mg/24 hr. Serum oxypurine analysis showed hypoxanthine 0.87 mg/dl and xanthine 0.35 mg/dl. Uric acid was not seen in this patient's serum but could be readily measured in normal control subjects. The technique can also be used to separate nucleotides from purine bases, and we have demonstrated its application to the measurement of erythrocyte hypoxanthine guanine phosphoribosyl transferase and adenine phosphoribosyl transferase in a kindred associated with the Lesch-Nyhan syndrome.
Chromatography, High Pressure Liquid↗
Thermodynamic behaviour of membrane enzymes in Duchenne muscular dystrophy.
Erythrocyte ghost preparations have been prepared from blood of Duchenne patients (DMD), female carriers of the disease and controls. Arrhenius plots of Na+, K+-ATPase activity of these membrane preparations show a biphasic response for controls. For 75% of DMD and carriers the response is monophasic. This is not an inherent property of the membrane since it can vary over time in the one individual and it can be induced in normal membranes by preincubation with DMD plasma. Arrhenius plots of AChE activity showed no such difference between the three sources of blood.
Acetylcholinesterase↗
Characterization of cardiac microsomal sarcoplasmic reticulum prepared from control and diabetic rats.
A method for the preparation of cardiac sarcoplasmic reticulum (SR) from rat heart is described. SR isolated from control and diabetic rats was characterized to determine if differences in calcium transport activity could originate as an artifact of preparation. Electron micrographs of cardiac SR preparations isolated from control and diabetic rats were indistinguishable. The yeild of SR and the mitochondrial membrane contamination were similar in both preparations. These results suggest that depression in diabetic rat cardiac SR microsomal function is not due to nonspecific alterations in the membrane preparations used.
Animals↗
Comparative effects of indomethacin, prostaglandin E1, and ibuprofen on bowel ischemia.
This study evaluates the effects of Indomethacin (IND), Prostaglandin E1 (PGE1), and Ibuprofen (IBP) in a bowel ischemia model. Laparotomy was performed in 80-gram rats (n = 260). Transient ischemia was induced by a one minute occlusion of the superior mesenteric artery. Animals were placed in five experimental groups: (I) ischemic controls (n = 80), (II) PGE1, 80 micrograms/kg IV (n = 20), (III) IBP, 12.5 mg/kg IV (n = 60), (IV) IND 15 mg/kg IV (n = 80) and (V) PGE1 + IND (n = 20). All medications were given just prior to laparotomy. Animals were evaluated for survival, length of survival and the presence of bowel necrosis and/or perforation at seven days. Survival was 18% in controls and was reduced to 5% by IND (p less than .005). Improved survival was observed with PGE1 (35%), TBP (31%) and PGE1 + IND (35%). IND resulted in early death, while PGE1, IBP, and PGE1 + IND all increased the length of survival (p less than .05). IND-treated rats had a high incidence of bowel perforation (greater than 40%). PGE1 reversed this effect when given concomitantly with IND. IBP had a significantly lower incidence of intestinal necrosis. These data suggest that infants treated with IND who are at risk for NEC should be carefully monitored for evidence of bowel necrosis. PGE1 and IBP may have a cytoprotective role in subjects at risk for bowel ischemia.
Alprostadil↗
Pancreatic abscess: an unusual complication of pancreatitis in infancy.
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Abscess↗
Blue Rubber Bleb Nevi as a cause of intussusception.
The Blue Rubber Bleb Nevus syndrome is a rare disease characterized by a distinctive type of hemangioma which involves the skin and the gastrointestinal tract. In the latter location, these lesions are often responsible for chronic blood loss and secondary anemia, and in rare situations may act as a leading point for an intussusception. The diagnosis of intussusception in children older than 3 or 4 yr is frequently difficult and delayed. In a child with typical skin lesions of the Blue Rubber Bleb Nevus syndrome, an acute illness with manifestations of intestinal obstruction should indicate the possibility of an associated intussusception.
Child↗
Snaring the guide for esophageal dilatation through a gastrostomy.
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Child↗
R L Gregory and others: the wrong picture of the picture theory of perception.
It is the position of R L Gregory and other cognitive theorists that perceptual knowledge conceived as an inner picture leads to an infinite regress, but that perceptual knowledge conceived as an abstract or coded representation does not. It is argued here that this view is mistaken. All inner representations, whether pictorial or abstract, lead to the regress because all representations, inner or outer, require interpretation, and hence an interpreter. The problem will not disappear, furthermore, by formalizing the representation because rule-following is not equivalent to interpretation. The regress can only be avoided if the whole organism is made the interpreter, and representations are given their appropriate place: in the external world, not inside heads.
Brain↗
The effects of spinal cord injury on somatosensory evoked potentials produced by interactions between afferent pathways.
The purpose of the present study was to determine the utility of somatosensory evoked potentials (SEPs) produced by interaction between afferent pathways for spinal cord injury evaluation. Interaction was measured as alterations in SEP configuration compared to controls. Monkeys anesthetized with N2O were used. Stimulus intensities were sufficient to excite all nerve fibers. The conditioning stimulus (CS) was applied to the left peroneal nerve and test stimulus (TS) to the left radial nerve. CS-TS intervals were 100 msec in duration. SEPs were recorded from primary cortical receiving area for the forelimb. Different surgical lesions were made at spinal cord level T3-T4. Amplitudes of TS-produced-SEPs remained unchanged postlesion. CS-produced-SEPs were found to be dependent upon the integrity of anterolateral column pathways. Accentuated interaction was observed following dorsal column ablation. Interaction was slightly enhanced after left hemisection but diminished after right hemisection or central cord lesion. Interaction between spatially separate afferent inputs as measured by SEP alteration was determined to be a sensitive indicator of spinal cord injury.
Afferent Pathways↗
Far-field potentials as a method of monitoring acute and chronic spinal cord injury.
Far-field potentials (FFPs) were studied in monkeys to determine the utility of such responses in evaluating acute and chronic spinal cord injury. Monkeys (Macaca fascicularis) were anesthetized with 70% N2O 30% O2, immobilized with pancuronium bromide, and maintained on a respirator. Spinal cord transections were made at level T3-T4 and included bilateral dorsal columns or anterolateral columns, right or left hemisection, or central cord lesions. Percutaneous stimulation of both posterior tibial nerves was performed at a frequency of 3 Hz using 3-4 mA for 0.3 msec duration. Potentials were recorded from chronically implanted epidural electrodes (right ear reference) through a 300-3,000 Hz band pass filter. Each far-field potential represents the average of 256 individual responses recorded for a duration of 25 msec before and after cord lesion for up to 8 weeks. Seven reproducible components in the far-field potential could be identified. Following dorsal column transection all components were reduced in amplitude. After anterolateral column transection only latencies were altered. Right or left hemisections caused both attenuation of component amplitudes and latency alteration. Central cord lesions resulted in no detectable amplitude or latency disturbances. Control records likewise showed no changes. No major alterations, following day 1 posttransection, were observed, attesting to the relative stability of far-field potentials over long periods of time. Far-field potentials therefore may be useful in monitoring spinal cord injury.
Animals↗
Carnitine and short-chain acylcarnitines in the lumen of the human male reproductive tract.
Bioautography of human semen demonstrated the presence of L-carnitine, acetylcarnitine, propionylcarnitine and C4-acylcarnitines (butyrylcarnitines). In studies designed to ascertain the organs secreting these compounds into semen it was found that: Quantitative analyses of semen obtained pre- and post-vasectomy showed markedly decreased L-carnitine concentrations, slightly decreased acetylcarnitine levels, and unchanged propionyl- and butyrylcarnitine concentrations as a result of vasectomy. The earlier portion of human split ejaculate samples characteristically contained higher concentrations of carnitine and its propionyl- and butyryl esters and a lower concentration of acetylcarnitine than did the later portion. Vas deferens luminal fluid contained carnitine and each of the short-chain acyl derivatives, as shown by bioautography. Prostatic fluid contained only small amounts of carnitine and its derivatives. Spermatozoa contained much more acetylcarnitine than free carnitine, and only trace amounts of the other acylcarnitines. It is concluded that carnitine in semen is secreted primarily by the epididymis, that a proportion of the acetylcarnitine derives from the seminal vesicles and epididymis, and that propionylcarnitine and butytylcarnitine enter semen, at least in part, together with the vas deferens contents.
Adult↗