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Biomedical subjects

S A Friedman

Publications and source records attributed to S A Friedman.

At least 91 records · Page 5Linked to original sources
PubMed1983

Lysozyme and lactoferrin quantitation in the crevicular fluid.

This study was designed to determine if quantitation of lysosomal products in crevicular fluid may be useful as a diagnostic test to evaluate clinical status in periodontal disease. Levels of lysozyme and lactoferrin were quantitated in crevicular fluid from patients with gingivitis, generalized adult periodontitis, localized juvenile periodontitis and normals. Crevicular fluid (CF) was collected from each patient by standardized filter paper strips and evaluated for lysozyme and lactoferrin by rocket immunoelectrophoresis. Levels of lysozyme (micrograms of protein per microliter of CF) were significantly higher in localized juvenile periodontitis patients as compared to gingivitis and adult periodontitis. On the other hand, levels of lactoferrin (micrograms of protein per microliter of CF) did not show significant differences between gingivitis, adult periodontitis and localized juvenile periodontitis. These results indicate that a lysozyme to lactoferrin ratio could be of value as a diagnostic test for localized juvenile periodontitis patients.

Adolescent↗
PubMed1981

Regulation of acetyl-CoA carboxylase by guanine nucleotides.

Acetyl-CoA carboxylase, a major rate-limiting enzyme for fatty acid synthesis, is subject to acute regulation by both allosteric modulation and covalent enzyme phosphorylation. Because citrate activation of the enzyme in vitro requires citrate concentrations far in excess of intracellular levels, we have attempted to identify other ligands which might mediate carboxylase activity. Heated liver extracts contain a potent endogenous activator of carboxylase assayed in dialyzed high speed liver supernatant; the activator elutes behind the salt volume of a Bio-Gel P-6 gel filtration column, is destroyed by alkaline phosphatase, and is adsorbed by charcoal. This activator activity is shared by several guanine nucleotides (5'-GTP, 5'-GDP, 5'-GMP, and 3':5'-cyclic GMP). Further separation of the endogenous activator by high pressure liquid chromatography reveals a carboxylase-activating compound which co-elutes with 5'-GMP. The guanine nucleotides are potent activators of carboxylase activity at intracellular nucleotide concentrations and permit expression of maximal enzyme velocity at cytosolic citrate concentrations. However, we have been unable to document any effects of guanine nucleotides on isolated rat liver acetyl-CoA carboxylase. While the mechanisms of these effects remain to be elucidated, they suggest that the guanine nucleotides may be important intracellular regulators of carboxylase activity and of fatty acid synthesis.

Acetyl-CoA Carboxylase↗
PubMed1981

Microsomal acetyl-CoA carboxylase: evidence for association of enzyme polymer with liver microsomes.

Fatty acid synthesis is traditionally viewed as being confined to the cytosolic cellular fraction, although a substantial body of data indicates that both microsomes and mitochondria are capable of initiating fatty acid synthesis and may contain acetyl-CoA carboxylase [acetyl-CoA:carbon-doxide ligase (ADP-forming), EC 6.4.1.2], fatty acid synthetase, and ATP-citrate lyase [ATP citrate (pro-3S)-lyase; ATP:citrate oxaloacetate-lyase (pro-3S-CH2COO- leads to acetyl-CoA; ATP-dephosphorylating), EC 4.1.3.8] activities. We have identified 32P-labeled acetyl-CoA carboxylase and 32P-labeled ATP-citrate lyase by immunoprecipitation of a rat hepatocyte microsomal preparation. In the transition between the fasting state (low rates of lipogenesis) and fasting/re-feeding (high rates), the fraction of total cytosolic plus microsomal acetyl-CoA carboxylase in the microsomes increases from 6% to 43%, whereas the microsomal proportion of total fatty acid synthetase and ATP-citrate lyase remains approximately 10%. Microsome isolation conditions favoring carboxylase polymerization (presence of citrate) promote microsomal association, whereas conditions favoring enzyme protomerization (malonyl-CoA, preincubation with cyclic AMP/ATP/Mg2+) diminish this association. The microsomal enzyme has a 5-fold higher specific activity than the cytosolic enzyme as determined by immunotitration. Sucrose density gradient analysis of the microsomal fraction indicates that a substantial portion of carboxylase activity sediments with marker enzymes for endoplasmic reticulum, plasma membrane, Golgi apparatus, and outer mitochondrial membrane, while cytosolic enzyme or isolated enzyme incubated under polymerizing conditions does not penetrate the gradient. These data suggest that the microsomes may be a significant locus of fatty acid synthesis initiated with association of acetyl-CoA carboxylase polymer with this fraction.

Acetyl-CoA Carboxylase↗
PubMed1980

Raynaud's phenomenon and thyroid deficiency.

We describe a patient with panhypopituitarism whose only clinical symptoms were related to Raynaud's phenomenon. Previously described patients with Raynaud's phenomenon due to hypothyroidism had Hashimoto's thyroiditis, an autoimmune disease associated with multisystem autoimmune disorders. The occurrence of Raynaud's phenomenon in hypothyroidism without thyroiditis and its prompt disappearance with thyroid replacement therapy demonstrate that decreased thyroid function per se is a cause of this vasospastic syndrome. Raynaud's phenomenon may be an early clue to the diagnosis of hypothyroidism.

Female↗
PubMed1979

Antibiotic control in a municipal hospital.

The choice of an antibiotic for a patient is often a difficult decision. The clinician must contend with a bewildering variety of bacteria and use a number of expensive and toxic antimicrobial agents judiciously. To deal with the problems of excessive and inappropriate use, the medical staff of Coney Island Hospital established compulsory, prospective antibiotic control. Two years after initiation of this program, we analyzed changes in sensitivity patterns of hospital flora, physicians' prescribing habits and antibiotic use. A trend toward increasing resistance on the part of some Gram-negative isolates to certain beta-lactam antibiotics was noted. Antibiotic costs decreased an average of 38%, while prescribing skills improved.

Anti-Bacterial Agents↗
PubMed1979

Antibiotic action of N-methylthioformohydroxamate metal complexes.

The antibiotic activity of metal complexes of N-methylthioformohydroxamic acid against gram-negative Escherichia coli NIHJ and gram-positive Staphylococcus aureus 209P was investigated. The kinetically labile, square-planar, divalent (Cu, Ni, and Pd) and octahedral, trivalent (Fe, Co, and Cr) complexes displayed activity, whereas the more inert platinum(II) or rhodium(III) complex displayed no activity, or activity only at elevated concentrations. The free ligand did not suppress the growth of the above organisms, and the sulfur atom of the ligand in its metal complexes appears crucial for activity. Uptake studies of radioactively labeled N-methylthioformohydroxamic acid, its nickel(II), platinum(II), iron(III), and rhodium(III) complexes were conducted in the Escherichia coli K-12 RW193 mutant, which is defective in the production of its native iron(III) transport agent, enterobactin. Uptake of (55)Fe or (63)Ni label from their metal complexes appeared to occur as free inorganic metal ions. The antibiotic activity of the iron(III) and nickel(II) complexes was not due merely to an enhanced accumulation of metal ions by the cell. Metal complexes of [(35)S]N-methylthioformohydroxamic acid enhanced the accumulation of (35)S label compared to that of the free ligand. The antibiotic activity and uptake data are discussed in terms of possible modes of action.

Anti-Bacterial Agents↗
PubMed1979

Kawasaki's disease appearing as erythema multiforme.

In 1967, Kawasaki reported an acute, febrile, mucocutaneous condition accompanied by swelling of cervical lymph nodes that affected infants and young children in Japan. He called it mucocutaneous lymph node syndrome. We report here a case of Kawasaki's disease with characteristic findings that demonstrated a typical erythema multiforme rash. With the increased number of reported cases of Kawasaki's disease in the United States, it becomes increasingly important to differentiate the exanthem of Kawasaki's disease from early erythema multiforme.

Diagnosis, Differential↗
PubMed1978

Arterial thrombosis in essential thrombocythemia.

The course of essential thrombocythemia has been observed in ten patients, ages 46 to 83, of whom nine were followed for a period of 4 months to 9 years. In contrast to the experience with essential thrombocythemia recorded in the literature, manifestations of arterial thrombosis were far more common than hemorrhage. In six of the ten patients, the presenting complaints were ascribable to incipient gangrene of the toes and several of these patients additionally developed occlusion of tibial and larger arteries while under our observation. All patients with incipient gangrene showed marked clinical improvement accompanying busulfan-induced reduction and normalization of the platelet count. Relapses in five patients after 2 to 87 months responded well to retreatment with busulfan. No patient has shown evolution to another myeloproliferative disorder. Essential thrombocythemia should be considered in the differential diagnosis of occlusive arterial disease.

Aged↗
PubMed1977

Initial characterization of hexose and hexitol phosphoenolpyruvate-dependent phosphotransferases of Staphylococcus aureus.

The phosphoenolpyruvate sugar phosphotransferases of Staphylococcus aureus were surveyed biochemically to determine substrate range, inducibility and constitutivity, and requirements for soluble sugar-specific proteins. The substrate range is similar to that of the phosphotransferases of enteric bacteria, but the staphylococcal mannose and sorbitol systems are very inefficient. In addition, S. qureus has phosphotransferase activities for lactose and sucrose. The systems tested fell into two broad classes. Sugars for which there was substantial constitutive activity (fructose, mannose, sucrose, and glucose and its nonmetabolized analogues) did not require sugar-specific soluble factors for phosphorylation. Only in the case of fructose did growth in the presence of these constitutive sugars induce the corresponding phosphotransferase activity to higher levels. Kinetic experiments with each of these constitutive sugars yielded biphasic Hofstee plots; i.e., the kinetics were not characteristic of single enzymes. Preliminary experiments suggest that sucrose phosphorylation may involve the glucose and/or fructose systems. Truly inducible sugar phosphotransferase systems represent a second class; those for lactose and mannitol are the only members thus far identified. These systems are absent from uninduced cells, require soluble sugar-specific factors, and exhibit linear Hofstee plots. Sorbitol is apparently transported very poorly by intact cells but is an inducer of the mannitol system; it is phosphorylated efficiently in vitro by extracts of cells grown on either hexitol, but is taken up by intact cells at 0.1% of the mannitol rate.

Cell Membrane↗
PubMed1976

Common manifestations of degenerative arterial disease.

The major focus of preventive medicine in the aged must be on the clinical consequences of peripheral arteriosclerosis rather than the disease process itself. Treating risk factors may be of some limited benefit. However, of most crucial importance is careful attention to premonitory symptoms and the state of the peripheral pulses including the abdominal aorta.

Aged↗