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Biomedical subjects

S Margolis

Publications and source records attributed to S Margolis.

At least 91 records · Page 5Linked to original sources
PubMed1977

Macular colobomas in Leber's congenital amaurosis.

Two siblings with Leber's congenital amaurosis had the unusual association of bilateral macular colobomas. In addition to the colobomas, the patients also had deafmutism, severe myopia, large corneas, and an unusual discrete area of peripapillary tapetoretinal sheen. Electrodiagnostic evaluation of patients with congenitally poor visual ascuity and a central retinal defect differentiated a localized loss of funciton from a degeneration involving the entire retina.

Adult↗
PubMed1977

Oculocutaneous albinism associated with Apert's syndrome.

Five of nine patients with Apert's syndrome (acrocephalosyndactyly) showed an associated hypopigmentation of hair, skin, and eyes. The hair color of these five patients ranged from light brown to blond, the skin was pale, and the irides hazel or blue. Iris transillumination and hypopigmentation of the fundus were present and associated with absent or diffuse foveal reflexes. Unlike most forms of classic oculocutaneous albinism, however, there was good visual acuity and no pendular nystagmus. The evidence indicated that the lack of pigmentation associated with the characteristic skeletal anomalies of Apert's syndrome resulted from a disturbance of independent, genetically related, processes occurring at a common point in gestation.

Acrocephalosyndactylia↗
PubMed1977

Structural alterations of extraocular muscle associated with Apert's syndrome.

An inferior oblique muscle from a patient with Apert's syndrome was examined by light and electron microscopy. Alterations in the muscle fibres, the myoneural junctions, and intramuscular nerves were observed. These data are not compatible with the widespread notion that motility disturbances in this syndrome are solely due to mechanical limitations.

Acrocephalosyndactylia↗
PubMed1977

Acute pancreatitis with hyperlipemia: studies with an isolated perfused canine pancreas.

Clinical evidence suggests that in many settings hypertriglyceridemia can initiate an episode of acute pancreatitis. Hydrolysis of triglycerides by pancreatic lipase with the local release of large quantities of free fatty acids (FFAs) has been proposed as the pathogenetic mechanism. To gather information to evaluate this mechanism an isolated, ex vivo, perfused pancreatic preparation was used. Control preparations remained normal in gross appearance, gained little weight (18 gm), extracted oxygen and glucose and released carbon dioxide, and continued to secrete during a 4 hour perfusion period. Serum amylase remained normal (972 CU/100 ml) as did FFAs (1.11 mEq/liter). When triglycerides were added to the perfusate to increase the serum triglycerides to 1,600 mg%, the glands became edematous, hemorrhagic, and gained considerable weight (52 gm) during the 4 hour perfusion period. Serum amylase became markedly elevated (2,624 CU/100 ml), as did the serum FFA (29.19 mEq/liter). When FFAs were added directly to the perfusate, the glands became edematous, hemorrhagic, and gained weight (90 gm), but did so much more rapidly than when triglycerides were added. These studies add support to the concept that hypertriglyceridemia can initiate pancreatic injury. Furthermore, they suggest that the mechanism may be through the release of FFAs.

Acute Disease↗
PubMed1976

Fluorescein angiography and vitamin A and oxalate levels in fundus albipunctatus.

Two patients had fundus albipunctatus, one of the variants of congenital stationary night blindness. Neither the white dots in the retinas of these patients nor the retarded course of dark adaptation characteristically associated with the disease could be attributed to vitamin A deficiency or raised oxalate levels since both substances were present in normal amounts. Fluorescin angiography showed multiple discrete lesions in the pigment epithelium not coincident with the ophthalmoscopically visible changes. Since the pigment epithelium is the storage site for bleached visual pigment, these findings suggest abnormalities that underlie the major functional deficit in this disease, that is, the slow recovery of retinal sensitivity.

Adult↗
PubMed1976

Blood glucose monitoring in symptomatic hypoglycemia.

The relationship between blood glucose levels and the onset of hypoglycemic symptoms was studied by continuous monitoring of blood glucose levels after an oral glucose load in nine adults with normal glucose tolerance, five with chemical diabetes without symptomatic hypoglycemia, and nine with chemical diabetes with symptomatic hypoglycemia. Symptoms were associated not only with a low level of blood glucose but with a rapid fall as well. These two parameters were used to calculate a "hypoglycemic index" (defined as the fall in blood glucose during a 90-minute period prior to reaching the minimum level, divided by the value of this minimum level). The hypoglycemic index was 2.3 +/- 0.6 (mean +/- S.D.) in the group of diabetic patients with symptomatic reactive hypoglycemia and 0.7 +/- 0.3 for the other groups. This index may aid in the diagnosis of patients with symptoms of hypoglycemia and equivocally low values of blood glucose.

Adult↗
PubMed1976

Retinal hemorrhages in the newborn.

There were 100 babies examined within 24 hours of birth. Retinal hemorrhages were found in 35% of newborns. Birth trauma from forceps delivery and prolonged labor were thought to be significant. Babies born by cesarean section were less likely to have retinal hemorrhages. Asphyxia was also found to be significant. The role of low plasma prothrombin levels, the vacuum extractor and increased intracranial pressure were discussed as etiologic agents. According to Von Noorden in 1973 there appears to be no positive correlation between hemorrhage of the macula and the occurrence of strabismus.

Birth Injuries↗
PubMed1976

Detection of inhibitors in reduced nicotinamide adenine dinucleotide by kinetic methods.

Methods are described for detection of lactate dehydrogenase (LDH) inhibitors in preparations of reduced nicotinamide adenine dinucleotide. They are (a) comparison of values by kinetic methods with those measured for highly purified NADH and (b) examination of Lineweaver-Burk plots. Chromatographic inhomogeneities are correlated with deviant values for the kinetic constants of NADH preparations. Lineweaver-Burk plots that curve upward at the high concentrations or have a larger or smaller than normal slope may indicate the presence of inhibitor. As determined in bicarbonate buffer (0.11 mol/liter, pH 7.9) by use of 0.600 mmol/liter pyruvate and NADH freshly separated from impurities by chromatography on diethyl-aminoethyl-cellulose, the Km (apparent) of NADH at 25 degrees C has the value 8.11 +/- 0.71 mumol/liter (SD, n = 28) with LDH-1 (pig heart, 2.48 +/- 0.05 U per milliliter of reaction mixture, or 41.3 +/- 0.8 nmol/liter per second). Under similar conditions, the Km (apparent) of NADH has the value of 8.57 +/- 1.58 mol/liter (SD, n = 21) with LDH-5 (pig muscle, 1.77 +/- 0.03 U/ml of reaction mixture), or 29.4 +/- 0.6 nmol/liter per second). At infinite substrate concentrations with the same pH, buffer, and temperature, the Km (apparent) for NADH was 26.0 +/- 0.63 mumol/liter with LDH-1 and 23.2 +/- 4.6 mumol/liter with LDH-5.

Chromatography, High Pressure Liquid↗
PubMed1976

Improved methods for the study of hepatic HMG CoA reductase: one-step isolation of mevalonolactone and rapid preparation of endoplasmic reticulum.

Two new methods are described for the study of hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase. (1) Endoplasmic reticulum was rapidly prepared by diluting a 10,000 g supernatant with buffer containing 8 mM calcium chloride. The yield of protein and the specific activity of HMG CoA reductase in the pellet subsequently obtained by low speed centrifugation were nearly identical to those in the microsomal pellet prepared by ultracentrifugation. This technique may be particularly useful in studies of the rapid, in vitro modulation of the enzyme. (2) Mevalonolactone was extracted into benzene from the HMG CoA reductase assay mixture with an efficiency of 58%. There was less than 1% extraction of HMG CoA, acetoacetate, or beta-hydroxybutyrate. The extracted mevalonolactone was at least 98% pure as judged by thin-layer chromatography with four different solvent systems. These improved methods should significantly aid studies of the physiological importance of HMG CoA reductase.

Alcohol Oxidoreductases↗
PubMed1975

Purification of histaminase (diamine oxidase) from human pregnancy plasma by affinity chromatography.

The present study describes the use of affinity chromatography to achieve a high degree of purification of histaminase (diamine oxidase, EC 1.4.3.6) from plasma of women in the third trimester of pregnancy. The procedure is based upon the binding of histaminase to cadaverine, a diamine substrate for the enzyme, which is coupled to Sepharose. Contaminant proteins were removed by high concentrations of NaCl (up to 1.0M), and the histaminase was then eluted from the column with a buffer containing 300--400 units/ml of sodium heparin. The purification technique has the following characteristics: (1) in optimal experiments, 3000-fold purification of enzyme was obtained; (2) the yield of enzyme was as great as 25%; (3) the binding of histaminase to the amine groups of the cadaverine appears to represent a true "affinity" phenomenon since enzyme bound to DEAE-cellulose under neutral pH conditions was eluted at much lower concentrations of NaCl (less than 0.4 M). The enzyme purified by the present procedure has the following properties: (1) disc gel polyacrylamide electrophoresis showed two protein bands for 1000--3000-fold pure histaminase; the major band may represent a contaminant protein, while the minor band corresponded to the position of histaminase activity; (2) a 90 000 molecular weight subunit for the plasma histaminase was identified on calibrated sodium dodecyl sulfate gels; this value agrees well with previous estimations for the subunit size of human placental histaminase; (3) the purified enzyme behaved as classical histaminase (diamine oxidase) in that it was totally inhibited by low concentrations of aminoguanidine, but was less inhibited by semicarbazide and by inhibitors of monoamine oxidase, and the enzyme was active against histamine and putrescine, but not against the monoamines benzylamine and tryptamine. Also, the enzyme was strongly inhibited by NaCl.

Amine Oxidase (Copper-Containing)↗
PubMed1975

A pathogenesis for alcoholic pancreatitis.

Twelve patients with prior episodes of alcoholic pancreatitis and hyperlipemia were admitted to a metabolic ward during a quiescent period. By lipid feeding (316 to 894 Gm. per day), significant hypertriglyceridemia (greater than 600 mg. per 100 ml.) was induced in 11 of the 12 patients. Seven of the 11 patients with hypertriglyceridemia developed abdominal pain similar to but not as severe as that experienced during prior attacks of pancreatitis. Four of the seven patients with abdominal pain developed serum amylase elevations, and, of the remaining three, one had a serum lipase elevation and one a urinary amylase elevation. Alcohol ingestion is known to increase serum triglyceride levels in many individuals. A prior study demonstrated that 41 percent of the patients presenting to our hospital with alcoholic pancreatitis had serum triglyceride elevations. The data from the present study suggest that increased serum triglycerides act as an important intermediary in the pathogenesis of acute pancreatitis in some alcoholic patients.

Adult↗