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Biomedical subjects

J L Hess

Publications and source records attributed to J L Hess.

At least 73 records · Page 4Linked to original sources
PubMed1980

Responses of superoxide dismutase and glutathione reductase activities in cotton leaf tissue exposed to an atmosphere enriched in oxygen.

Responses of superoxide dismutase (EC 1.15.1.1) and glutathione reductase (EC 1.6.4.2) activities were evaluated in leaf tissue from intact cotton plants (Cotton Branch 1697) which were exposed to 75% O(2), 350 microliters per liter CO(2) for 48 hours. Soluble protein was extracted from O(2)-treated and control tissue, and enzyme levels were determined. Superoxide dismutase activity in cotton leaf tissue was high (26 units per milligram protein) under normal conditions of 21% O(2), saturating light, and limiting CO(2), and neither qualitative nor quantitative differences in the cyanide-sensitive or -insensitive forms of the enzyme occurred in response to hyperoxic conditions. Glutathione reductase activity, however, was 2- to 3-fold higher in extracts from tissue exposed to 75% O(2). No increase in activity was observed for the peroxisomal enzymes, glycolate oxidase (EC 1.1.3.1) and catalase (EC 1.11.1.6). Results are consistent with an integrated pathway involving superoxide dismutase and glutathione reductase for protection of sensitive leaf components against detrimental effects of intermediate reduction products of O(2).

Journal Article↗
PubMed1980

MMPI factor scale differences among heroin addicts differing in race and admission status.

Predictions that personalities of compulsive heroin users differ as a function of ethnicity and admission status were tested in an analysis of covariance design (covariates: age, intelligence, and socioeconomic status) using four MMPI factor scales as personality measures (i.e., anxiety, repression, somatization, and unconventionality). Those volunteering for treatment (n = 260) expressed significantly more anxiety and somatization than nonvolunteers (n = 67); White heroin users (n = 144) registered significantly more anxiety and repression than Blacks (n = 183). These findings, contraindicating the notion that one personality characteristic is associated with heroin addiction, underscore the necessity for developing personality typologies before assessing the role of psychosocial dimensions in theories and treatment of heroin addiction.

Adult↗
PubMed1979

Clinical utilization of mechanical sutures for intestinal anastomosis in Macaca mulatta.

Using three mechanical stapling instruments that employ stainless steel wire staples, a Mann-Bollman fistula was created on the terminal ileum in 27 rhesus monkeys (Macaca mulatta). Two functional end-to-end anastomoses were accomplished and an ileostium constructed. Staples of various sizes were used; it was found that pediatric-sized staples were necessary for the intestinal tissue of these primates. Six months after surgery, microscopic examination revealed encapsulation of the staples by granulomatous inflammatory tissue. When staples of the proper size were selected, mechanical suturing provided rapid and consistent anastomoses, and wound closures had less edema, inflammation and necrosis than with conventional suturing methods.

Animals↗
PubMed1976

Lenticular opacities in young rats as a consequence of maternal diets low in tryptopham and/or vitamin E.

The relative effect upon lens transparency of a diet low in both tryptophan and vitamin E was compared to diets low in either nutrient alone during development. Thirty-three percent of 126 progeny from 19 litters at weaning were found to have either unilateral or bilateral lenticular opacities when the maternal diet during gestation and lactation provided only 75 mg L-tryptophan and 0.1 mg dl-alpha-tocopheryl acetate per 100 g diet. No opacities were seen in 179 progency from 20 litters when tryptophan alone was restricted, and only 6% incidence was detected when vitamin E was the sole limiting nutrient. The data reveal a previously unrecognized association between tryptophan and vitamin E relative to fetal lens development.

Animals↗
PubMed1975

Partial purification and characterization of aspartate aminotransferases from seedling oat leaves.

As relatively little information is available on the properties of aspartate aminotransferase from photosynthetic tissue, isolation and characterization of the two major electrophoretically distinct forms of this enzyme from seedling oat leaf homogenates were undertaken. These two forms are designated I for the more anionic form and II for the less anionic form. Form I, 80 to 90% of the total activity, has been purified to a specific activity of 120 mumol/min/mg of protein (1100-fold) and is estimated to be 90 to 95% homogeneous, as judged by analytical polyacrylamide gel electrophoresis. Form II, 10 to 20% of the total activity, has been purified to a specific activity of approximately 6 mumol/min/mg of protein (300-fold). Both forms exhibit optimal activity at pH 7.5. Michaelis constants do not differ greatly between forms I and II and are similar to those reported for the pig heart cytosolic enzyme as well as aspartate aminotransferase from other plant sources. A molecular weight of 130,000 for the purified aspartate aminotransferase I was estimated by sedimentation equilibrium centrifugation; molecular weights of the two forms are similar as estimated by sucrose density gradient centrifugation. No activation by pyridoxal phosphate has been observed during purification.

Aspartate Aminotransferases↗
PubMed1969

Glycolate stimulation of oxygen evolution during photosynthesis.

Glycolate and glyoxylate stimulated 100% to 300% the rate of oxygen evolution by Scenedesmus in the light in the absence of added carbon dioxide. This stimulation occurred either aerobically or anaerobically, and was sensitive to CMU. Aerobic dark respiration was stimulated 25% to 100% by glycolate. This phenomenon was best demonstrated with synchronized Scenedesmus at the stage of cell division. For glycolate stimulation of oxygen evolution, a dark preincubation of 1 minute or less was necessary. In comparative test with other compounds of metabolism and photosynthesis, the stimulation of oxygen evolution was greatest by glycolate and glyoxylate. In a proposed scheme glyoxylate serves as a terminal hydrogen acceptor from NADPH produced by photosynthesis, and it thereby stimulates oxygen evolution when carbon dioxide is not available. Transformation of glycolate to glyoxylate in these cells would have to occur in the absence of oxygen.

Eukaryota↗
PubMed1967

Glycolate pathway in algae.

No glycolate oxidase activity could be detected by manometric, isotopic, or spectrophotometric techniques in cell extracts from 5 strains of algae grown in the light with CO(2). However, NADH:glyoxylate reductase, phosphoglycolate phosphatase and isocitrate dehydrogenase were detected in the cell extracts. The serine formed by Chlorella or Chlamydomonas after 12 seconds of photosynthetic (14)CO(2) fixation contained 70 to 80% of its (14)C in the carboxyl carbon. This distribution of label in serine was similar to that in phosphoglycerate from the same experiment. Thus, in algae serine is probably formed directly from phosphoglycerate. These results differ from those of higher plants which form uniformly labeled serine from glycolate in short time periods when phosphoglycerate is still carboxyl labeled. In glycolate formed by algae in 5 and 10 seconds of (14)CO(2) fixation, C(2) was at least twice as radioactive as C(1). A similar skewed labeling in C(2) and C(3) of 3-phosphoglycerate and serine suggests a common precursor for glycolate and 3-phosphoglycerate. Glycine formed by the algae, however, from the same experiments was uniformly labeled. Manganese deficient Chlorella incorporated only 2% of the total (14)CO(2) fixed in 10 minutes into glycolate, while in normal Chlorella 30% of the total (14)C was found in glycolate. Manganese deficient Chlorella also accumulated more (14)C in glycine and serine.Glycolate excretion by Chlorella was maximal in 10 mm bicarbonate and occurred only in the light, and was not influenced by the addition of glycolate. No time dependent uptake of significant amounts of either glycolate or phosphoglycolate was observed. When small amounts of glycolate-2-(14)C were fed to Chlorella or Scenedesmus, only 2 to 3% was metabolized after 30 to 60 minutes. The algae were not capable of significant glycolate metabolism as is the higher plant. The failure to detect glycolate oxidase, the low level glycolate-(14)C metabolism, and the formation of serine from phosphoglycerate rather than from glycolate are consistent with the concept of an incomplete glycolate pathway in algae.

Carbon Isotopes↗
PubMed1967

Changes in Chlorophyll a/b Ratio and Products of CO(2) Fixation by Algae Grown in Blue or Red Light.

Chlamydomonas and Chlorella were grown for 10 days in white light. 955 muw/cm(2) blue light (400-500 mmu) or 685 muw/cm(2) red light (above 600 mmu). Rates of growth in blue or red light were initially slow, but increased over a period of 5 days until normal growth rates were reestablished. During this adaptation period in blue light, total chlorophyll per volume of algae increased 20% while the chlorophyll a/b ratio decreased. In red light no change was observed in the total amount of chlorophyll or in the chlorophyll a/b ratio. After adaptation to growth in blue light and upon exposure to (14)CO(2) with either blue or white light for 3 to 10 minutes, 30 to 36% of the total soluble fixed (14)C accumulated in glycolate-(14)C which was the major product. However, with 1 minute experiments, it was shown that phosphate esters of the photosynthetic carbon cycle were labeled before the glycolate. Glycolate accumulation by algae grown in blue light occurred even at low light intensity. After growth of the algae in red light, (14)C accumulated in malate, aspartate, glutamate and alanine, whereas glycolate contained less than 3% of the soluble (14)C fraction.

Journal Article↗