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Biomedical subjects

J Jung

Publications and source records attributed to J Jung.

At least 145 records · Page 8Linked to original sources
PubMed1989

The relationship of daily hassles, social support, and coping to depression in black and white students.

Black and White American college students were compared to determine how daily hassles, coping strategies, and social support related to depression. Although the mean intensity of hassles did not differ, Black students reported a higher frequency of hassles. Cumulative severity of hassles, defined in terms of both intensity and frequency was therefore higher for Black students. White students perceived more support from friends than from family, but the opposite held for Black students. Mean scores on type of coping (active problem solving, seeking social support, or avoidance) were similar, as were the reported levels of depression. Hierarchical multiple regression showed that the severity of hassles was directly related to depression for both groups. Race did not interact with any index of social support, except perceived family support, which was related to lower depression among Black students. There was no support for the notion that social support serves as a buffer against depression.

Adaptation, Psychological↗
PubMed1988

Absorption kinetics of dietary hydrolysis products in conscious pigs given diets with different amounts of fish protein. 2. Individual amino acids.

1. Concentrations of amino acids (AA) in blood obtained from arterial and portal permanent catheters were measured together with the portal hepatic blood flow-rate during a post-prandial period of 8 h, in nine conscious pigs (initial mean body-weight 49.3 (SEM 1.8) kg) receiving experimental meals (500, 600 or 1000 g) at 3-4 d intervals from 6-8 to 20 d after the surgical implantation of the catheters and electromagnetic flow probe. The semi-synthetic starch-based diets contained variable amounts of fish meal giving crude protein (nitrogen x 6.25; CP) concentrations (g/kg) of 80 (seven meals), 120 (seven meals), 160 (five meals) and 240 (three meals). 2. During the post-prandial period, variations in the individual blood AA concentrations were parallel to those of total amino-N (Rérat et al. 1988) to a greater or lesser extent according to the AA considered. Portal concentrations, which always exceeded arterial ones (except for glutamic acid and glutamine), increased quickly and, after a peak, returned slowly to reach initial values (small intake) or above (large intake) after 8 h. 3. Relations between amounts of each AA appearing during 8 h after the meal and amounts ingested were characterized by a highly significant linear regression (with the exceptions of glutamic acid and cystine). There were also close and significant relations between amounts of AA absorbed during the first 2 and 4 h after the meal and the amounts ingested. 4. For a mean intake of 90 g CP, aromatic AA showed the highest hourly absorption coefficients (about 0.10/h), and sulphur-AA (0.07/h), lysine (0.07/h) and arginine (0.056/h) the lowest ones. Alanine was synthesized (amounts absorbed within 8 h exceeding those ingested) at the expense of glutamic acid (absorption coefficient 0.01/h). 5. For a given period of time, the AA absorption coefficients decreased with increasing intake, but not in the same proportions for all AA, resulting in an enrichment (lysine, arginine, serine, proline) or depletion (branched-chain AA, histidine) of the absorbed mixture. 6. Some substances of the urea cycle were synthesized in rather large amounts in the gut wall (for a mean level of intake of 90 g CP: citrulline 2.41 g/8 h, ornithine 1.09 g/8 h). Blood glutamine was taken up by the gut wall in larger amounts (4.28 g/8 h).

Amino Acids↗
PubMed1988

Ethylene production by sunflower cell suspensions : effects of plant growth retardants.

From a variety of undifferentiated plant cell suspensions, 2,4-dichlorophenoxyacetic acid-dependent cells of sunflower (Helianthus annuus L. Spanners Allzweck) produced large quantities of ethylene. The maximum rate was about 1 nanomole x gram fresh weight(-1) x hour(-1) during the exponential growth phase. The action of various compounds known to interfere with ethylene formation in plant tissue was studied in sunflower cell suspensions. The influence on ethylene, 1-aminocyclopropanecarboxylic acid (ACC), and N-malonyl-ACC (MACC) levels suggested that the final steps in ethylene synthesis resemble those of other plant systems. This makes sunflower cells suitable for analyzing the effects of biologically active compounds on cellular ethylene biosynthesis. In particular, plant growth retardants of the norbornenodiazetine and triazole type inhibited ethylene production of sunflower cells. On the other hand, the ACC level was considerably elevated while that of MACC did not change significantly. It is assumed that the conversion of ACC to ethylene catalyzed by the ethylene-forming enzyme was influenced.

Journal Article↗
PubMed1987

Regulation of plant morphology by growth retardants: effects on phytohormone levels in soybean seedlings determined by immunoassay.

The effects of the growth retardants tetcyclacis, a norbornenodiazetine, and LAB 150 978, a dioxanylalkenyl triazole, on seedling growth and endogenous levels of phytohormone-like substances in Glycine max L. cv Maple Arrow were studied. The levels of phytohormone-like substances in the root and in the various shoot tissues were analyzed by immunoassay. After seed treatment with both compounds, shoot growth was reduced more intensively than root growth. Both compounds decreased, on a fresh weight basis, the amount of various immunoreactive gibberellins when compared with the levels in control plants, especially in the shoot tip. Likewise, the growth retardants lowered the levels of abscisic acid-like material, particularly in the primary leaf, the epicotyl and the root. In contrast, the levels of trans-zeatin-riboside and dihydrozeatin-riboside-type cytokinins were considerably elevated by the growth retardants, mainly in the primary leaf, epicotyl, and hypocotyl. On the other hand the level of isopentenyladenosine-like material was less influenced. In general, the immunoreactive 3-indoleacetic acid content in the different plant parts was changed only slightly. It is assumed that besides their effect on gibberellin content both compounds interfere directly or indirectly with the regulation of the endogenous levels of abscisic acid and cytokinins. This might be seen as an additional mode of action of growth retardants explaining some side effects on developmental processes of treated plants, e.g. delayed senescence and enhanced chlorophyll concentration in the leaves.

Journal Article↗
PubMed1986

Morphologic and morphometric analysis of muscle in X-linked myotubular myopathy.

The X-linked form of myotubular myopathy is highly lethal in neonates. Several autopsy-derived muscles from two probands of a new kindred who survived for 100 days because of intensive supportive care were analyzed by light microscopy, morphometry, enzyme histochemistry, and electron microscopy. The results were compared with a similar analysis of muscle from control fetal and neonatal subjects. The findings, in addition to the characteristic centronucleated hypotrophic myofibers, included widespread myofiber degeneration and focal contraction band necrosis that differed from the types seen in other myopathic and dystrophic muscle diseases. A high frequency of degenerating nuclei that often contained large nucleoli was observed. Because of the paradoxic nuclear morphology, nuclear failure (in migration and myofibrillogenesis) is believed to be of central importance in the pathogenesis of this disease.

Histocytochemistry↗
PubMed1986

How significant others cope with problem drinkers.

About half of the 234 college students surveyed have a close friend or relative whose drinking creates problems for the significant other. A variety of coping responses were identified but none of them was considered effective for either the drinker or significant other.

Adaptation, Psychological↗
PubMed1984

Hepatitis B follow-up among Indochinese refugees.

During 1979 and 1980 the Department of National Health and Welfare carried out a survey and later routine testing to determine the prevalence of serologic markers of hepatitis B in Indochinese refugees entering Canada. Between March and July 1981 the hepatitis-B-marker status of 220 selected refugees in the Ottawa-Hull area was reassessed. Overall, 173 (79%) of the participants had the same serologic markers when retested, but in 47 (21%) the markers had changed. The most significant changes were the loss of antigenemia in 22% of those who had been HBsAg-positive and the appearance of evidence of infection in 18% of those who had been seronegative. Most of these changes occurred among persons under 30 years of age, especially females aged 10 to 19 years.

Adolescent↗
PubMed1981

Cardiovascular disease mortality in Canada.

During the past two decades approximately one half of all deaths in Canada were due to cardiovascular diseases. Ischemic heart disease and cerebrovascular disease caused more than 60% and 20% of those deaths respectively. The mortality rates for ischemic heart disease in males increased slightly until 1965 and then dropped substantially, whereas the rates for females, which were declining at least since the early 1960s, accelerated in their decline. As a consequence, the rates for males remain almost twice as high as those for females. The reductions were initially observed in males 25 to 34 years old and in all age groups of females, but became apparent in a wider range of ages in the second period reviewed (1969 through 1977). The mortality of cerebrovascular disease has gradually diminished for both sexes since the 1950s, but the decline has been more pronounced among females, who originally had the higher rate. Marked geographic differences in mortality rates still exist in Canada despite the decline in death rates for both ischemic heart disease and cerebrovascular disease in all regions of the country. Surprising regional differences in times of onset of these declines have been demonstrated. For ischemic heart disease Ontario maintains the highest and the Prairies the lowest mortality rates. Quebec, despite a sustained decline, still ranks third, while the Pacific region shows the second-lowest rates in the country. The Atlantic region showed the lowest rates of decline in the period reviewed. The reduction in the mortality of ischemic heart disease in Canada (16.4% between 1969 and 1977) must be considered real for a variety of reasons. Direct evidence is not available to elucidate whether the reduction is the consequence of reduced incidence, increased survival or a combination of the two factors. The potential role of various factors that may have contributed to this decline is briefly discussed in this article.

Adult↗
PubMed1981

Transient kinetics of electron-transfer reactions of flavodoxins.

Stopped-flow and laser photolysis methods have been used to investigate the rates of electron-transfer reactions of fully reduced riboflavin and the three oxidation states of Clostridium pasteurianum flavodoxin. Both normal and 7,8-dichloroflavin analogues were studied. Redox reagents included oxygen, ferricyanide, ferric EDTA, and several c-type cytochromes as oxidants and the semiquinone of 5-deazariboflavin as a reductant. The dependence of the rate of oxidation of the semiquinone form of the dichloro analogue flavodoxin upon oxidant concentration has provided clear evidence for the existence of a complex in the reaction pathway. Rate constant comparisons demonstrate that dichloro substitution decreases the rate of flavodoxin semiquinone oxidation by at least 1-2 orders of magnitude. The limiting first-order rate constants were found to be dependent on the redox potential of the oxidant, as would be predicted by theory if these were reflecting the actual electron-transfer reaction. Rate constant decreases upon chlorine substitution were also observed for the reduction of both oxidized and semiquinone forms of flavodoxin by deazariboflavin semiquinone. These results, considered in conjunction with the redox potential shift of the flavodoxin produced by the chlorine substitution, provide support for the hypothesis that electron transfer to and from the semiquinone form of the flavodoxin involves direct participation of the dimethylbenzene ring of the flavin. A comparison of oxidation rate constants for free and protein-bound fully reduced flavin suggests that the protein environment does not markedly influence coenzyme reactivity in this oxidation state.

Clostridium↗
PubMed1981

Scanning electron-microscopy of plague in Papillon-Lef:evre syndrome.

Supra and subgingival plaque associated with periodontal lesions in patients with Papillon-Lefèvre syndrome were studied by examining extracted teeth and associated soft tissue by scanning electron and light microscopy. Four zones of plaque were described according to their location along the tooth surface. Supragingivally, cocci, filamentous bacilli and "corncob" formations were seen. Fusiform bacilli colonized the surface of supragingival plaque on the root surface. Subgingival sites, particularly apical areas, had numerous spirochetes adherent to the plaque surface as well as directly to the cementum surface. Microcolonies of bacteria, probably Mycoplasma, could be seen in the subgingival plaque. The findings of a potentially pathogenic plaque, attached subgingival spirochetes and microcolony formation may have important therapeutic and research implications.

Bacteria↗