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K J Friedman

Publications and source records attributed to K J Friedman.

49 records · Page 3Linked to original sources
PubMed1986

Temperature-induced changes in fatty acid composition of myelinated and non-myelinated axon phospholipids.

The olfactory (non-myelinated) and trigeminal (myelinated) nerve axons of garfish show changes in phospholipid fatty acid composition when these fish are acclimated to temperatures ranging from 11 to 35 degrees C. Myelinated and non-myelinated nerve axons show similar changes in the percent saturated, percent 16-carbon, percent 18-carbon, and percent 20-carbon-and-greater unsaturated fatty acids. The observed changes in phospholipid fatty acid composition fit a linear regression model suggesting a gradual change in axonal phospholipid fatty acid composition with temperature. The temperature-induced changes in garfish nerve phospholipid fatty acid composition are consistent with the general observation of increased saturated fatty acid residues in plasma membrane phospholipids of organisms acclimated to higher environmental temperatures. The garfish data are similar to data previously obtained for goldfish tissues and Tetrahymena.

Acclimatization↗
PubMed1986

Delayed healing in full-thickness wounds treated with aluminum chloride solution. A histologic study with evaporimetry correlation.

Optimizing wound healing parameters seems to be the utmost importance in the present age of sophisticated wound care and dressings. We studied the effect of two hemostatics: 30% aluminum chloride and ferric subsulfate (Monsel's solution) on the rate of wound healing in Yucatan miniature hairless pigs. Wound healing was examined in occluded and nonoccluded full-thickness 3-mm punch biopsy wounds. Wounds were treated either with 30% aluminum chloride solution or ferric subsulfate solution or were allowed to clot with minimal pressure from a gauze pad. The course of wound healing was followed utilizing evaporimetry readings from the wound sites in addition to periodic histologic examination in an attempt to correlate the evaporimetry readings with corresponding histology. Delay in reepithelialization was noted histologically both in wounds treated with aluminum chloride and in those treated with ferric subsulfate compared to controls. Presumably this delay was the result of tissue necrosis caused by these hemostatic agents, resulting in slightly larger and less cosmetically acceptable scars. Plots of evaporimetry data revealed a biphasic pattern of water loss during healing, with an initial rapid decline in water loss followed by a much slower decline. Histologic reepithelialization seemed to correlate best with the point on the evaporimery curve where the slope changed from the phase of rapid water loss to a slower rate.

Aluminum↗
PubMed1985

Changes in sterol and phospholipid fatty acid composition in Refsum's disease fibroblasts grown in the presence of phytol.

Fibroblasts derived from an individual with Refsum's disease (GM 3896) and a normal control (GM 1717) were grown in the presence of 0, 0.1, 0.2, and 0.3 mM phytol. Cultures were analyzed for total sterol content, and the fatty acid composition of the extractable phospholipids. The fatty acid composition of the phospholipids are similar for control and Refsum's disease fibroblasts when grown on media lacking phytol. However, the addition of phytol to the growth medium produces differences in fatty acid composition between the phospholipids extracted from control and Refsum's disease cells. With regard to sterol composition, data are presented which suggest that an altered sterol is induced in Refsum's disease fibroblasts by the presence of phytol in the growth medium. The possible relationship of these findings to the mechanism of Refsum's disease is discussed.

Cell Line↗
PubMed1982

Role of lipids in the Neurospora crassa membrane: IV. Biochemical and electrophysiological changes caused by growth on phytanic acid.

Neurospora crassa strain cel, which is deficient in fatty acid synthesis, was grown with phytanic acid supplementation. The temperature dependence of membrane potential is increased by growth on phytanic acid. A temperature change of 40 degrees C produces a change of 184 mV in phytanic acid-grown cells as compared to a 50 mV change for cel grown on palmitic acid or wild-type. Membrane resistance (measured as DC input resistance) of phytanic acid-grown cells did not differ from cel grown on palmitic acid or wild-type. Lipid analysis of cel grown on phytanic acid revealed approximately 7 mole percent phytanic acid incorporation into phospholipids, no change in phospholipid base composition, a reduction of ergosterol content from 80 to 30 percent, and the induction of beta sitosterol, a sterol not usually present in Neurospora. beta sitosterol accounted for approximately 60 percent of the sterol present. Incorporation of 7 mole percent phytanic acid into phospholipids lowers the phase transition temperature by approximately 5 degrees C, and decreases the heat content of the phase transition (delta H) slightly. Results are discussed in relation to Refsum's disease, a human neurological disorder associated with high plasma levels of phytanic acid. It is proposed that high intracellular phytanic acid concentration induces novel sterol synthesis and that the incorporation of the novel sterol into the membrane is responsible for the increased temperature sensitivity of membrane potential. The excitable membrane deficits observed in patients with Refsum's disease may be explained by such a mechanism.

Cell Membrane↗
PubMed1977

Role of lipids in the Neurospora crassa membrane. II. Membrane potential and resistance studies; the effect of altered fatty acid composition on the electrical properties of the cell membrane.

The effect of doubling the saturated fatty acid content on the electrophysiology of Neurospora crassa membranes was studied. Intracellular membrane input resistance (Rm) and potential (Em) were measured for wild-type (w/t) and cel- (Tween 40) organisms as a function of temperature. Over the 0 to 40 degrees C temperature range studied, mean Em values of both w/t and cel- (Tw 40) organisms increased from -160 to -210 mV. This difference is greater than that expected from Nernst potential considerations, indicating an active component of Em. This active component is insensitive to a doubling of the saturated fatty acid content. Rm exhibits a temperature dependence and hysteresis. Averaged data indicate an increase in Rm with decreased temperature. The slope of the temperature dependence varies among individual hyphae. Above 17.5 degrees C cel- (Tw 40) hyphae averaged greater than 70% higher values of Rm than w/t. Below 17.5 degrees C w/t Rm data divided into low and high temperature dependence groups, while cel- data exhibited a low temperature dependence. The results are discussed in relation to gel-liquid crystal phase transitions, membrane fluidity, and the contribution of fatty acid structure to membrane electrical properties.

Cell Membrane↗
PubMed1977

Role of lipids in the Neurospora crassa membrane. I. Influence of fatty acid composition on membrane lipid phase transitions.

The relationship between lipid composition and phase transition was investigated by differential scanning calorimetry for intact and membrane phospholipid extracts of wild-type (w/t) and the cel-(Tw 40) mutant of Neurospora crassa. The cel-(Tw 40) mutant (grown on minimal, sucrose medium supplemented with Tween 40 at approximately 34 degrees C) had approximately twice the saturated fatty acid content of w/t organisms grown at approximately 22 degrees C. The gel-liquid crystal phase transitions of ergosterol-free extracts derived from w/t and cel-(Tw 40) occur at -31 and -11 degrees C, respectively. The heats of transition (delta H) of these extracts were 1 and 13 cal/g, respectively. The addition of ergosterol (the predominant sterol in Neurospora) to the phospholipid extracts decreased the observed heats of transition, but did not alter the transition temperature. Intact Neurospora, whether w/t or cal-(Tw 40) did not manifest similar gel-liquid crystal phase transitions in the differential scanning calorimeter. However, an endothermic peak at approximately 30 degrees C was observed in intact cells and extracted phospholipids of both w/t and cel-(Tw 40) organisms. This peak was insensitive to the addition of ergosterol, had a low heat content (delta H congruent to 1 cal/g), and was reversible.

Calorimetry, Differential Scanning↗
PubMedDate not supplied

Cytology of metastatic neuroendocrine (Merkel-cell) carcinoma in pleural fluid. A case report.

A case of Merkel-cell (neuroendocrine) carcinoma of the skin with extensive metastases, including pleural effusion, occurring over 20 years after primary resection and treatment, is reported. The histologic appearance of the primary neoplasm was identical to that seen in the biopsy specimens of the metastatic carcinoma involving the great toe and inguinal lymph nodes and to that of the residual neoplasm tissue found at necropsy. Electron microscopic examination of a lymph node metastasis demonstrated cytoplasmic microfilaments and numerous dense-core, peripheral, neurosecretory granules, as previously described in Merkel-cell carcinoma. Cytologic examination of a pleural fluid specimen demonstrated numerous small malignant cells closely resembling the cells seen in the histopathologic sections from the surgical and necropsy tissues involved by metastatic carcinoma. This is the first report of the cytologic findings in a patient with Merkel-cell carcinoma metastatic to the pleural cavity.

Carcinoma, Small Cell↗