Biomedical subjects
Publications and source records attributed to R Wood.
A case of benign symmetrical lipomatosis (Madelung-Launois-Bensaude syndrome) is described. The characteristic clinical features and the association with chronic alcoholism are reported.
To determine the accuracy of skinfold thickness measurements in body composition assessment, skinfold thicknesses, bioelectrical impedance, body density by underwater weighing, and total body water by deuterium dilution were determined in 105 healthy adults who varied widely in body fatness. Body fat ranged from 2.9% to 61.2% of body weight and a substantial number of obese subjects was included. The correlation between body fat calculated from skinfold equations and body fat measured by underwater weighing was in the same range as that between body fat estimated from impedance and underwater weighing. However, body fat calculated both from skinfold equations and bioelectrical impedance tended to be underestimated compared with body fat calculated from underwater weighing and total body water in the most obese subjects. In obese subjects it was not possible to measure significant numbers of skinfold thicknesses because of the inadequate size of the calipers.
A variety of opinions have been expressed in the literature concerning asbestos and laryngeal cancer. This paper presents an analysis of epidemiological studies based on criteria that prioritized the most heavily exposed cohorts. Emphasis was given to the six cohorts or subcohorts with lung cancer relative risk estimates of 2 or more. The two groups of workers with the highest lung cancer relative risk estimates (4.06 and 3.28) both gave strong support for a causal association of asbestos and laryngeal cancer, with relative risk estimates of 1.91 (90% confidence limits 1.00 to 3.34) and 3.75 (90% confidence limits 1.01 to 9.68), respectively. Confounding with cigarette smoking or alcohol consumption does not explain the findings. Case-control studies gave mixed results, but generally supported the hypothesis. It was concluded that asbestos is a probable cause of laryngeal cancer in view of the reasonable consistency of the studies, the strength of the association in key studies, the evidence for dose-response relationships, and the biological plausibility for asbestos being a cause of laryngeal cancer.
A particular version of the Westgard-Barry-Hunt-Groth (Westgard) multi-rule quality-control system is studied by Monte Carlo simulation. The principal focus is on the amount of distortion in the working power curve caused by skewness in the distribution of analyte measurements. The effect of using only the first two rejection modes of the Westgard system is also studied.
The role of asbestos in the etiology of lung cancer and of mesothelioma of the pleura and peritoneum has been well documented. The evidence for a causal association between asbestos and other human cancers is not as extensive but suggests that asbestos may be carcinogenic at several different sites. This paper is concerned specifically with a possible causal association between asbestos and human kidney cancer. A review of the evidence to date indicates that only three human studies have sufficient statistical power to detect an excess mortality from kidney cancer among workers exposed to asbestos. All three were occupational cohort studies, and two of these gave strong direct evidence for such an excess; a study of U.S. insulators (kidney cancer SMR = 2.22, 90% CI 1.44-3.30), and a study of U.S. asbestos products company workers (kidney cancer SMR = 2.76, 90% CI 1.29-5.18). The third study, of Italian shipyard workers, reported excess mortality from "cancers of the kidney, urinary bladder, and other urinary organs" (SMR = 1.98, 90% CI 1.42-2.70). Further support for a causal association includes studies finding asbestos fibers in human kidneys and urine, as well as reports of kidney tumors in two animal bioassays. It is concluded that asbestos should be regarded as a probable cause of human kidney cancer.
This paper describes the smokeless tobacco use practices and oral health problems of members of a minor league professional baseball team. Seventeen of 25 ball-players reported current use of smokeless tobacco. Gingival recession and lesions in the oral mucosa were more common in smokeless tobacco users than nonusers. Reported use of smokeless tobacco was greater during baseball season than in the off-season. Of the 19 current and past users, 15 reported first using smokeless tobacco after entering professional baseball. To discourage the use of smokeless tobacco by professional athletes, teams should stop accepting free samples and do a better job educating players about health consequences associated with use.
Tested the hypothesis that induced conceptions of ability as a stable entity or as an acquirable skill would affect self-regulatory mechanisms governing performance in a simulated organization. Ss served as managerial decision makers in which they had to match employees to subfunctions and to discover and apply managerial rules to achieve a difficult level of organizational performance. Those who performed the challenging managerial task under an entity conception of ability suffered a loss in perceived self-efficacy, lowered their organizational goals, and became less efficient in their analytic strategies. Ss who managed the organization under an acquirable skill conception of ability sustained their perceived self-efficacy, set challenging organizational goals, and used analytic strategies effectively. These divergences in self-regulatory factors were accompanied by substantial differences in organizational performance. Path analysis revealed that perceived self-efficacy had both a direct effect on organizational performance and an indirect effect through its influence on analytic strategies. Personal goals also affected organizational performance through the mediation of analytic strategies. The relation of prior organizational performance to subsequent performance was mediated entirely by the combined influence of the self-regulatory factors.
Tested the hypothesis that perceived controllability and stringency of performance standards would affect self-regulatory mechanisms governing performance attainments of a simulated organization. Ss who managed the simulated organization under a cognitive set that organizations are not easily controllable displayed low perceived self-efficacy, even when standards were within easy reach, and lowered their organizational goals. Ss who operated under a cognitive set that organizations are controllable maintained a strong sense of self-efficacy, set increasingly challenging goals, and exhibited effective analytic thinking. The divergent changes in these self-regulatory factors were accompanied by large differences in organizational attainments. Path analyses revealed that perceived self-efficacy, which was affected by prior accomplishments, influenced subsequent organizational performance through its effects on analytic strategies. After further experience, the performance system was regulated more extensively and intricately by Ss' self-conceptions of efficacy. Perceived self-efficacy affected subsequent organizational attainments both directly and indirectly through its influence on personal goal challenges. Personal goals, in turn, enhanced organizational attainments directly and through mediation of analytic strategies.
The disappearance rate of macaque chorionic gonadotrophin (MCG) was investigated in six pregnant monkeys. The animals were hysterectomized with a rapid initial ligature of the uterine and ovarian vessels with minimal uterine manipulation. The entire procedure lasted less than 2 min. Blood samples were drawn before and after the hysterectomy (5, 20, 30, 45, 60, 90, 120 min), and MCG was measured in serum by radioimmunoassay. For all animals, a progressive decrease (rate of disappearance) of MCG values in serum was found, which appeared to follow a double exponential curve. Averaged curves produced disappearance rates of T1/2(1) = 17.2 h for the first compartment (72 h), and T1/2(2) = 87.1 h for the second compartment (156 h). The results suggest that the disappearance of MCG after interruption of pregnancy in rhesus monkey is very similar to that occurring in humans. These data demonstrate that the rhesus monkey is an excellent animal model to study the dynamics of placental hormone secretion in humans.
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Biopsies from the common bile ducts from seven patients undergoing surgery for biliary obstruction due to stones or malignancy were studied histochemically and electron microscopically. The surface of the bile duct is lined by a tall epithelium which extends into diverticula. Apically, they contain some neutral and sialated mucosubstances. Fucosyl residues were found in the Golgi apparatus and along the apical cell membrane. The latter is lined by microvilli. There was a well-developed rough endoplasmic reticulum and Golgi apparatus and a small number of apical secretory droplets. Large numbers of lipid droplets were present basally in some cells. Lipid-containing macrophages were also seen intra-epithelially and in the lamina propria. This suggests a possible pathway for lipid transport. The glands were lined by cuboidal cells, some containing much mucus--sulphated, sialated, and neutral with a basal nucleus. A well-developed endoplasmic reticulum and Golgi apparatus were found with abundant secretory droplets. The glandular epithelium contained lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin. These may play a protective role. The lamina propria contained scattered smooth muscle cells amongst the fibroblasts and inflammatory cells.
Previous studies from this laboratory have established that acquired resistance of murine L1210 leukemia cells to L-phenylalanine mustard (L-PAM) and other alkylating agents is accompanied by a two-to threefold elevation in their glutathione (GSH) concentration (Biochem. Pharm. 31:121). In an attempt to gain insight into the mechanism by which resistant tumor cells maintain their increased GSH content, we have assessed the possible role of gamma-glutamyl transpeptidase (gamma-GT), a membrane bound enzyme involved in GSH metabolism. These results indicate that the enzyme is present in both sensitive and resistant murine L1210 leukemia cells but that the cellular content of gamma-GT is elevated two-to threefold in L-PAM resistant cells as compared to their sensitive counterparts. This elevation in enzymatic activity correlates well with the increased cellular GSH content in resistant cells. The results of a detailed kinetic analysis of gamma-GT activity indicate that there is no difference, between cell types, in the apparent Km of the enzyme for the gamma-glutamyl donor (L-gamma-glutamyl-p-nitroanilide) or the acceptor (glycylglycine). However, the apparent Vmax is increased two-to threefold in L-PAM resistant tumor cells. Investigation into the role of gamma-GT in the extracellular metabolism of GSH indicates that resistant tumor cells metabolize two-fold more GSH than do sensitive cells and that such metabolism results in a similar difference in the intracellular concentration of cysteine. Results of studies with cellular lysates also indicate a role for the enzyme in the supply of cysteine to the glutathione precursor pool of the tumor cell and in the maintenance of elevated GSH concentrations in cells resistant to alkylating agents.
Two wide-bore capillary columns are evaluated for their applicability to the purge-and-trap technique and GC/MS analysis of 34 volatile organics. Neither column is able to completely resolve all 34 compounds, as is also typical of the packed column; however, the analysis is faster than with the packed column (18 to 21 min compared to 30 min), and the column effluent is introduced directly into the mass spectrometer without requiring an open-split interface. Method precision, as assessed from the instrument response at a concentration of 50 micrograms/L per component, is better than +/- 5% for 41% of the compounds using the VOCOL column (diphenyl dimethyl polysiloxane with crosslinking moieties) and for 53% of the compounds using the 007 column (95% methyl 5% phenyl silicone). The instrument response is linear from 20 to 200 micrograms/L for most compounds, and the amounts loaded to either column without serious distortion of the peak shape or resolution can be as high as 5 micrograms per component. Because the VOCOL column resolved more compounds than the 007 column within approximately the same analysis time, this column is further tested for performance with groundwater samples.
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Subcellular fractions of nuclei, mitochondria, endoplasmic reticulum, plasma membrane and cytosol were prepared from liver and hepatoma 7288CTC. Marker enzyme activities, biochemical compositions and electron microscopy were used to establish purity. Hepatoma NADH: cytochrome C reductase and 5'-nucleotidase exhibited abnormal subcellular distributions. The lipids from the subcellular fractions were examined in detail. Mitochondria and plasma membranes were characterized by elevated percentages of diphosphatidylglycerol and sphingomyelin, respectively, in both tissues. All hepatoma subcellular fractions contained dramatically elevated levels of sphingomyelin and cholesterol, two components that form preferential strong complexes in vitro. The fatty acid composition of hepatoma sphingomyelin differed markedly from liver and, unlike liver, did not exhibit organelle specific compositions. Some hepatoma lipid classes contained reduced percentages of palmitate while others contained higher levels. Hepatoma phosphatidylcholine and phosphatidylethanolamine from organelles contained lower percentages of long chain polyunsaturated fatty acids than liver. Generally, unique fatty acid profiles exhibited by individual phospholipid classes of liver subcellular fractions were absent or much reduced in the hepatoma. The ratios of oleate to vaccenate were near one for most of the phospholipid classes of most liver fractions, but all hepatoma classes, with few exceptions, contained a much higher percentage of oleate in all subcellular fractions. The hypothesis is proposed that the origin of some acyl moieties for the biosynthesis of various hepatoma lipid classes differs from liver sources. The possible changes in acyl pools, sources and compartments for complex lipid biosynthesis could result in change in the quantities of molecular species that could contribute to the abnormal properties of the hepatoma membranes.
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The stability of amiodarone hydrochloride in intravenous admixtures was studied. Amiodarone hydrochloride 900 mg was mixed with 500 mL of either 5% dextrose injection or 0.9% sodium chloride injection in polyvinyl chloride or polyolefin containers; identical solutions were also mixed with either potassium chloride 20 meq, lidocaine hydrochloride 2000 mg, quinidine gluconate 500 mg, procainamide hydrochloride 2000 mg, verapamil hydrochloride 25 mg, or furosemide 100 mg. All admixtures were prepared in triplicate and stored for 24 hours at 24 degrees C. Amiodarone concentrations were determined using a stability-indicating high-performance liquid chromatographic assay immediately after admixture and at intervals during storage. Each solution was visually inspected and tested for pH. Amiodarone concentrations decreased less than 10% in all admixtures except those containing quinidine gluconate in polyvinyl chloride containers. The only visual incompatibility observed was in admixtures containing quinidine gluconate and 5% dextrose injection. In most solutions pH either decreased slightly or remained unchanged. Amiodarone hydrochloride is stable when mixed with either 5% dextrose injection or 0.9% sodium chloride injection in polyvinyl chloride or polyolefin containers alone or with potassium chloride, lidocaine, procainamide, verapamil, or furosemide and stored for 24 hours at 24 degrees C. Amiodarone should not be mixed with quinidine gluconate in polyvinyl chloride containers.
The sources of octadecenoic acid (18:1) and the importance of the stearoyl-CoA desaturase system in maintaining elevated levels of this fatty acid in the Morris hepatoma 7288C have been investigated. Sterculic acid, an inhibitor of the stearoyl-CoA desaturase system, when added to the culture medium, inhibited the production of monoenoic fatty acids through de novo synthesis by 90% while the production of saturated fatty acids and cholesterol was unaffected. Sterculic acid also inhibited 18:1 formation through desaturation of exogenous stearate (18:0) by 80%. These results indicate that the stearoyl-CoA desaturase system is responsible for most, if not all, of the 18:1 produced within these cells and that an alternate, sterculic acid-insensitive, pathway for 18:1 biosynthesis is not functioning in this cell line. Measurements of fatty acid synthesis, using 3H2O, show that de novo synthesis accounts for approx. 30% of the cellular 16:1 and 18:1 mass, while contributing 63% and 95% of the stearate and palmitate mass, respectively. Cells grown in the presence of sterculic acid displayed a 50% decrease in 18:1 levels while levels of both palmitate and stearate increased. These effects were maximal at 20-30 microM sterculate. Polyunsaturate levels were unaffected. The 50% decrease in 18:1 levels in treated cells could be completely accounted for by the inhibition of de novo 18:1 biosynthesis and the inhibition of exogenous 18:0 desaturation. This enzyme system, although low in activity when measured in this tissue, is responsible for a major portion of the 18:1 observed in these cells.