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A gas–liquid chromatographic micromethod for quantitation of cholesterol in 20 μl of plasma was developed using 5α-cholestane as an internal standard, saponification with tetramethylammonium hydroxide–isopropanol, and extraction with tetrachloroethylene–methyl butyrate. Cholesterol levels in plasma samples were calculated by comparing cholesterol–cholestane peak height ratios with those of preassayed reference plasma. Over a plasma cholesterol range of 44 to 468 mg/100 ml, the gas–liquid chromatographic micromethod and the automated ferric chloride colorimetric method gave nearly identical results (r = 0.99) in duplicate aliquots of 131 plasma samples.

The effects of acute withdrawal from cigarette smoking on indocyanine green (ICG) clearance and antipyrine pharmacokinetics were studied in healthy young male volunteers. Two separate crossover clinical trials, each using 12 subjects, were used to compare the disposition of the drugs from 24 to 36 hours after withdrawal to the disposition found under control conditions. The median difference of ICG clearance and all antipyrine pharmacokinetic parameters from smoking control was less than 13%, indicating that short-term smoking withdrawal had no effect large enough to be of clinical significance on hepatic blood flow or hepatic drug-metabolizing capacity. Rates of hepatic blood flow were normal in comparison with values published for larger sample populations. The lack of any clinically significant effect of smoking withdrawal on hepatic blood flow or on the disposition of antipyrine, a drug with very low hepatic extraction, indicates that on a pharmacokinetic basis, changes in dosage regimens for most drugs are not necessary on acute withdrawal from smoking.

Relationships between maternal cholesterol and phytosterol intake, and concen- trations of cholesterol and phytosterol in maternal plasma, breast milk, and infant plasma were evaluated in 14 lactating mothers and their infants. The mothers took an ad libitum diet for 30 days after delivery and then were randomized to one oftwo diets: one containing 190 mg cholesterol and 1200 mg phytosterol per day, and a polyunsaturated/saturated fat ratio of 1.8; the second, a high cholesterol diet calculated to contain 520 mg cholesterol and 50 mg phytosterol/day, with a polyunsaturated/saturated fat ratio of 0. 12. After 4 weeks on either diet, the mothers then crossed over to the other for a second 4 week period. Breast milk constituted the infants' sole intake during the two periods. During the ad libitum, low cholesterol-phytosterol enriched, and high cholesterol- low phytosterol diet periods, mean ± SE breast milk cholesterol (milligrams per grams total milk fat) was unchanged (2.4 ± 0.4, 2.4 ± 0.1, and 2.5 ± 0.2, respectively), despite a significant reduction of maternal plasma cholesterol from 220 ± 14 mg/dl (ad libitum) to 166 ± 7 (low cholesterol diet), and 186 ± 6 (high cholesterol diet). Infant plasma cholesterol, 143 ± 8 mg/dl on maternal ad libitum diet, was not significantly changed during maternal low cholesterol diet (140 ± 7), or during maternal high cholesterol diet (150 ± 8). Maternal milk phytosterol (0.17 ± 0.03 mg/g) on ad libitum diet, rose to 2.2 ± 0.3 on low cholesterol-phytosterol enriched diet, and fell to 0.7 ± 0.1 on the high cholesterol-low phytosterol diet, P < 0.0001. Maternal plasma phytosterol levels changed similarly, being 2.3 ± 0.9 mg/dl on ad libitum, 11.7 ± 0.9 on low cholesterol, and 4.9 ± 1.3 on high cholesterol intakes, P < 0.0001. Infant plasma phytosterol levels, 0.37 ± 0.04 mg/dl on both maternal ad libitum and high cholesterol intakes, rose to 0.54 ± 0.05 on maternal low cholesterol, phytosterol enriched diet (P < 0.01). Maternal dietary and plasma phytosterol levels were closely correlated (r = 0.62, P = 0.0001), as were plasma and milk phytosterol levels (r = 0.39, P = 0.02). Milk phytosterol and infant plasma phytosterol levels were also closely related (r = 0.43, P = 0.008). Conversely for cholesterol, the only significant maternal correlation was between dietary and plasma levels, r = 0.43, P = 0.004. No significant correlations were observed between maternal plasma and milk cholesterol levels, or between maternal milk and infant plasma cholesterol levels. On the polyunsaturate enriched as compared to a saturate enriched diet, milk content of linoleic acid was more than doubled, while oleic, palmitoleic, stearic, palmitic, and myristic acid levels were reduced. Am. J. Clin. Nut,. 31: 1347-1354, 1978.

Sural nerves obtained at autopsy and biopsy were examined histologically and subjected to gas-liquid chromatography. There was no correlation between the clinical severity or type of neuropathy and the histological appearance or the fiber numbers and diameter spectra of the nerves. Gas-liquid chromatography distinguished sural nerves obtained from patients with neuropathy occurring in association with diabetes, chronic respiratory disease and alcoholism from controls. It is suggested that this method of analysis of sural nerves may prove useful in diagnosis and in the understanding of the pathogenesis of peripheral neuropathies.

Fatty acids of the phospholipid fraction of bronchoalveolar lavage fluid from patients with bacterial pneumonia or with the adult respiratory distress syndrome were chromatographed and the patterns compared with those for a control group. In the control group, palmitic acid (16:0) was the predominant fatty acid, accounting for 58.0% (SD 8.25%) of the total fatty acid, a proportion significantly higher (p less than 0.001) than in the distress-syndrome group (42.1%, SD 4.88%) or the acute pneumonia group (32.1%, SD 1.73%). There was a greater proportion of oleic acid (18:1) in the disease groups; thus the ratio of palmitic to oleic acid was useful in distinguishing these three groups. No patient with a palmitic/oleic acid ratio greater than 2.45 had evidence of parenchymal inflammation. Of those with a ratio less than 1.3, 89% had acute bacterial pneumonia.

The intravenous disposition of theophylline was determined in 12 healthy young male smokers during periods of smoking and short-term withdrawal (24 to 36 hours), using a crossover design. Median half-life, clearance, volume of distribution, hepatic extraction, and intrinsic clearance of theophylline during withdrawal were within +/- 5% of the corresponding median control (smoking) parameters and were normal in comparison with values published for smokers. The lack of change in the pharmacokinetic profile of theophylline indicates that adjustment of the dosage regimen should not be necessary immediately after smoking withdrawal.

A gas-liquid chromatographic micromethod for quantitation of cholesterol in 20 micro l of plasma was developed using 5alpha-cholestane as an internal standard, saponification with tetramethylammonium hydroxide-isopropanol, and extraction with tetrachloroethylene-methyl butyrate. Cholesterol levels in plasma samples were calculated by comparing cholesterol-cholestane peak height ratios with those of preassayed reference plasma. Over a plasma cholesterol range of 44 to 468 mg/100 ml, the gas-liquid chromatographic micromethod and the automated ferric chloride colorimetric method gave nearly identical results (r = 0.99) in duplicate aliquots of 131 plasma samples.

Adult male rats were starved by allowing them one fifth of their measured daily food consumption until they lost 40% of their initial body weights. Some of these rats were then refed until their initial body weights were reached. We measured the total content of the following in the lung tissue of fed, starved, and refed animals: (1) elastin, (2) hydroxyproline, and (3) protein. Body weight and lung dry and wet weights were significantly reduced in starved and similar in refed rats compared with fed animals. Total contents of crude connective tissue, hydroxyproline, elastin, and protein were significantly lower in starved than in fed rat lungs. After refeeding, hydroxyproline content returned completely to levels found in fed rats, but other components only partially returned to normal values. These results provide a biochemical counterpart for our previous observations on the effects of starvation and refeeding on lung mechanics and morphologic aspects. It appears that the emphysema like changes in the lungs of starved rats are at least partly related to the loss of connective tissue elements.

Fatty acids of the phospholipid fraction of bronchoalveolar lavage fluid from patients with bacterial pneumonia or with the adult respiratory distress syndrome were chromatographed and the patterns compared with those for a control group. In the control group, palmitic acid (16:0) was the predominant fatty acid, accounting for 58.0% (SD 8.25%) of the total fatty acid, a proportion significantly higher (p less than 0.001) than in the distress-syndrome group (42.1%, SD 4.88%) or the acute pneumonia group (32.1%, SD 1.73%). There was a greater proportion of oleic acid (18:1) in the disease groups; thus the ratio of palmitic to oleic acid was useful in distinguishing these three groups. No patient with a palmitic/oleic acid ratio greater than 2.45 had evidence of parenchymal inflammation. Of those with a ratio less than 1.3, 89% had acute bacterial pneumonia.

Regional myocardial ischemia was produced in anesthetized pigs by occluding the left anterior descending coronary artery. Mitochondria were prepared from both normally perfused and ischemic myocardium after 2 h of occlusion. Mitochondria from the ischemic area exhibited an 89% increase in cholesterol content from 32.7 +/- 1.9 (control) to 62.0 +/- 0.47 (ischemic) nmol/mg protein with no change in either total phospholipid content or in membrane fatty acid composition. This increase in mitochondrial membrane cholesterol was accompanied by an increase in membrane microviscosity as indicated by increased fluorescence polarization using the fluorescent membrane probe, 1,6-diphenyl-1,3,5-hexatriene. In these same experiments the Arrhenius plot discontinuity temperature of oligomycin-sensitive adenosinetriphosphatase (ATPase) activity fell from 20.0 to 14.2 degrees C. Our results suggest that, during the myocardial ischemic process in pigs, there is an intracellular redistribution of free cholesterol that produces a marked increase in mitochondrial membrane cholesterol content. This appears to produce an altered mitochondrial membrane lipid bilayer packing, resulting in increased membrane microviscosity and, possibly, altered inner membrane ATPase function. Intracellular cholesterol redistribution may thus contribute to the cell membrane damage that occurs during the myocardial ischemic process.

Clinical, light microscopical, ultrastructural, and biochemical studies were done on nerve and muscle biopsy specimens from five patients with the oculo-cerebral-renal syndrome of Lowe. Four patients were American Indians, a racial group in whom this disease has not previously been recognized. The hypotonia, areflexia, and diffuse atrophy of muscles are associated with slowed motor nerve conduction velocities, and the morphologic changes in sensory nerves are attributed to a "dying-back" phenomenon probably resulting from an unknown metabolic derangement.

Adult rats received one fifth of their measured daily food consumption until they lost 40% body weight. Some of these rats were then refed until they reached their initial body weight. We measured the following in fed, starved, and refed animals: (1) disaturated phosphatidylcholine (DSPC) content of lung tissue and of lavage fluid, (2) protein content of lung tissue and of lavage return, and (3) DNA and RNA content of lung tissue. In starved lungs, tissue and lavage DSPC content, total protein and RNA contents, and RNA/DNA ratios were significantly lower than in fed rats. After refeeding, DSPC values returned completely to normal, whereas protein, DNA, and RNA contents were significantly higher than in fed rats. The RNA/DNA ratio was similar in the fed and refed groups. Changes in lavage DSPC are consistent with the increased surface elastic forces in starvation and their return to normal with refeeding reported by us previously. It appears that starvation leads to a reduction in cell size without changes in cell number and that refeeding is associated with a more significant increase in cell number than in cell size.

Diethylstilbestrol (DES) is readily extracted into toluene from biological fluids or tissue homogenates. Sodium carbonate is added to the initial mixture to eliminate potentially interfering substances. The toluene is extracted with a very small volume of aqueous trimethylphenylammonium hydroxide. This solution generates dimethyl DES in the vaporizer of a gas-liquid chromatograph. An internal standard, dienestrol (DI), is added at the beginning of the procedure and is partitioned and methylated in the same manner as DES. The DES and DI derivatives are well separated in less than 6 min on an ov-17 column. The entire analysis requires less than 15 min for a fluid specimen and less than 25 min for a solid tissue specimen. Seven samples can be analyzed each hour on a single column with a flame ionization detector. The relative standard deviations at levels from 2.5 to 100 ppm in bile are less than 5%. The lower limit of sensitivity is 8 ppb in a 1 ml bile sample.

A gas-liquid chromatographic procedure has been developed to quantitate dipicolinic acid in bacterial spores. The culture, washed from a plate, was hydrolyzed with acid containing the internal standard, pyridine-2,4-dicarboxylate, and then extracted into methyl isobutyl ketone. The internal standard and dipicolinic acid were then extracted into a small volume of trimethylphenylammonium hydroxide. Injection of the resultant quaternary ammonium salts into a gas chromatograph yielded, via thermal decomposition, the methyl ester derivatives of the dipicolinic acid and the internal standard. The amount of dipicolinic acid in the sample was determined from a standard curve. The method was sensitive to 100 ng of dipicolinic acid per sample and was 1,000 to 5,000 times more sensitive than the commonly used methods. Preparation of the sample required less than 1.5 h and less than 15 min of the analyst's time.

Fatty acids were analyzed by a new method which involved their isolation from hexane extracts of serum or brain tissue in aqueous potassium hydroxide (10 microliter) and methylation directly in this solution with methyl iodide. The resulting fatty acid methyl esters were partitioned into ethylene chloride (25 microliter) and were quantitated by gas-liquid chromatography. The procedure was documented by comparison with conventional methylation reactions on serum fatty acids. This method, which avoids thin-layer chromatography and which measures individual free fatty acid concentrations in 20-mg brain tissue samples, should be of particular value for examining regional free fatty acids in brain following ischemia and trauma.

Two groups of rats (young and old) were food-deprived for 3 wk and were compared with age-matched fed groups. Final body weight and dry and wet weights of lungs were significantly reduced in both young and old starved rats. As determined by saline volume-pressure (VP) curves, lungs of young starved rats accepted significantly less volume at all pressure levels compared with lungs of young fed rats. When expressed as a percent of maximum lung volume, the VP curve in young starved rats was significantly shifted upward at low lung volumes. In the old rats, the VP curves were similar in fed and starved rats. Total lung content of protein, DNA, crude connective tissue, hydroxyproline, and elastin were significantly reduced in young starved compared with young fed rats, whereas in old starved rats only protein and DNA contents were lower than those in old fed animals. It appears that in rapidly growing young rats starvation leads to growth retardation, loss of connective tissue components, and possibly reduction in tissue elastic forces at low lung volumes, whereas starvation has no significant effects on lung mechanics and connective tissue in old rats.