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Biomedical subjects

W Gross

Publications and source records attributed to W Gross.

At least 91 records · Page 5Linked to original sources
PubMed1992

Release of carrot plasma membrane-associated phosphatidylinositol kinase by phospholipase A2 and activation by a 70 kDa protein.

Plasma membranes were isolated from carrot (Daucus carota L.) cells grown in suspension culture and treated with phospholipase A2 from snake or bee venom for 10 min. As a result of this treatment, phosphatidylinositol kinase activity was recovered in the soluble fraction. There was no detectable diacylglycerol kinase or phosphatidylinositol monophosphate kinase activity released from the membranes after the phospholipase A2 treatment. Treating the plasma membranes with phospholipase C or D did not release PI kinase activity. The phospholipase A2-released PI kinase was activated over 2-fold by a heat stable, soluble 70 kDa protein. The partially purified 70 kDa activator increases the Vmax but does not affect the Km of the phospholipase A2-released PI kinase.

1-Phosphatidylinositol 4-Kinase↗
PubMed1992

Apolipoprotein B(Arg3500----Gln) allele specific polymerase chain reaction: large-scale screening of pooled blood samples.

A two-step polymerase chain reaction (PCR) method for the rapid detection of the apolipoprotein B(Arg3500----Gln) mutation in a mixture of pooled blood samples is described. In the first step PCR, a short gene fragment surrounding codon 3500 is amplified. Subsequently the reaction product is subjected to a second amplification in which a mutation-specific primer is used. A PCR product is generated only if the mutant sequence is present in the DNA pool. Individuals carrying the mutation can then be identified by PCR with mutagenic primers and MspI restriction typing, essentially as described by Hansen et al. (J. Lipid Res. 1991. 32: 1229-1233).

Alleles↗
PubMed1992

AIDS awareness and risk behaviors among dually disordered adults.

An exploratory needs assessment was conducted among 50 clients of an abstinence-oriented outpatient clinic for adults experiencing coexisting drug abuse and chronic mental disorders. Findings revealed that, despite education and prevention efforts, sample members possessed considerable misinformation about AIDS and continued to engage in high risk heterosexual practices. Their knowledge level was not associated significantly with their admission diagnoses. Knowledge level also did not correlate significantly with safer sexual practices. These findings have implications for the development of AIDS education and prevention programs for dually disordered clients. To be effective, AIDS prevention and education efforts must be targeted at the clients' specific needs. Clear, explicit information about AIDS must be provided. In addition, behavioral-attitudinal change strategies that focus on the high-risk situations encountered by the clients and teach them alternative safer sex practices are required.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Phosphorylation of lysophosphatidylinositol by carrot membranes.

sn-1 Palmitoyl lysophosphatidylinositol is found in carrot suspension culture cells and can be phosphorylated to [32P]lysophosphatidylinositol monophosphate (LPIP) when [gamma 32P]ATP is added to isolated membranes. Based on in vivo labeling studies, [3H]inositol sn-1 palmitoyl LPIP was found predominantly in the plasma membrane-rich fraction or upper phase isolated by aqueous two-phase partitioning and LPI was found in the intracellular membrane-rich fraction or lower phase (Wheeler and Boss, Plant Physiol. 85, 389-392, 1987). While both membrane fractions phosphorylated LPI in vitro, the apparent Km for LPI in the intracellular membrane fraction was 180 microM and for the plasma membrane was 580 microM. When cells were treated with the ionophore, monensin, the percentage of [3H]inositol LPIP increased in the whole cell lipid extract. However, the monensin treatment decreased the amount of [3H]inositol LPIP and PIP recovered in the plasma membrane fraction relative to the sum of the individual lipid, [3H]inositol LPIP or PIP, respectively, recovered in both membrane fractions.

Cell Membrane↗
PubMed1991

Phenotyping of apolipoprotein E by immunoblotting in immobilized pH gradients.

An immunoblotting method for the determination of apolipoprotein E (apoE) phenotypes has been developed. Delipidated plasma proteins are focused in an immobilized pH gradient, and transferred to polyvinylidene difluoride (PVDF) membranes. ApoE isomorphs are identified by immunoperoxidase staining. The method allows reproducible assignment of apoE phenotypes without isolation of triglyceride-rich lipoproteins. Only small amounts of serum are required. There are several important steps in the procedure: (i) delipidation is indispensable, (ii) carrier ampholytes have to be added to the gels and to the sample buffer, and, (iii) on immunostaining, polyvinylidene difluoride membranes provide an excellent signal-to-background ratio.

Apolipoproteins E↗
PubMed1991

Apolipoprotein (a) concentrations are not related to the risk of venous thrombosis.

The protein moiety of lipoprotein (a) consists of apoB-100 and apolipoprotein (a). Lipoprotein (a) is an independent risk factor for premature atherosclerosis. Apolipoprotein (a) and plasminogen are structurally homologous. Through interference with the fibrinolytic system, lipoprotein (a) may act as a thrombogenic factor. Therefore, we have determined apolipoprotein (a) in 203 patients with venous thrombosis and/or embolism below the age of 45 years and in 115 healthy volunteers. The frequency distribution of apolipoprotein (a) in thrombosis patients resembled that in the reference group. It is concluded that there is no clinically relevant association between apolipoprotein (a) concentrations and the risk of venous thrombosis in young subjects.

Adult↗
PubMed1991

Fourth report of the cooperative, open-ended study of slowly growing mycobacteria by the International Working Group on Mycobacterial Taxonomy.

The open-ended study of the International Working Group on Mycobacterial Taxonomy is an ongoing project to characterize slowly growing strains of mycobacteria that do not belong to well-established or thoroughly characterized species. In this fourth report we describe two numerical taxonomic clusters that represent subspecies or biovars of Mycobacterium simiae, one cluster that encompasses the erstwhile type strain of the presently invalid species "Mycobacterium paraffinicum," one cluster that is phenotypically very similar to Mycobacterium avium and Mycobacterium intracellulare but may be a separate genospecies, one cluster that appears to be phenotypically distinct from M. avium but reacts with a nucleic acid probe specific for M. avium, and three tentatively defined clusters in proximity to a cluster that encompasses the type strain of Mycobacterium malmoense. Of special practical interest is the fact that one of the latter three clusters is composed of clinically significant scotochromogenic bacteria that can be misidentified as the nonpathogenic organism Mycobacterium gordonae if insufficient biochemical tests are performed.

Agglutination Tests↗
PubMed1991

Mechanism of activation of A2 adenosine receptors. II. A restricted collision-coupling model of receptor-effector interaction.

Existing models describing the kinetics of receptor-effector interaction were found to be insufficient to account for the experimental findings on adenylate cyclase activation by A2 adenosine receptors described in the preceding manuscript [Mol. Pharmacol. 39: 517-523 (1991)]. We have, therefore, chosen another approach and have developed discrete computer simulations of receptor-effector interactions taking place on a spherical membrane. These simulations were based on the following principles: (a) receptors activate effectors in a catalytic manner, and (b) diffusion of receptors and effectors is slow, so that receptors will only activate effectors that are in their vicinity at the time of agonist occupation. Using several experimentally determined parameters, these simulations could reproduce the experimental findings on adenylate cyclase activation by A2 adenosine receptors described in the preceding manuscript. In addition, by appropriate choice of the simulation parameters, they are shown to accommodate the behavior of several other models of receptor-effector interactions.

Azides↗
PubMed1991

[Fetal movement and acceleration behavior in hypertension in pregnancy].

Under standardized conditions, 26 pregnant women with pregnancy-related hypertension of different degrees were submitted to cardiogram-synchronous recording of fetal body and respiratory movements. The gestational age was between the completed 34th and 38th weeks. Of the 26 fetuses of the risk group, 20 were normotrophic and 6 hypotrophic. 40 normotrophic unimpaired fetuses of the same gestational age served as a control group. The average duration of the examination period was 70 minutes. The fetal movement and acceleration behaviours did not differ between the normotrophic fetuses of the risk group and those of the control group. The hypotrophic fetuses from the risk group, however, had significantly lower fetal body and respiratory activities than the normotrophic fetuses from this group. The same holds true for the degrees of heart rate activity. It can be concluded that pregnancy-related hypertension as the only pregnancy complication does not have a measurable influence on fetal movement and acceleration behaviours. This is true for both treated and untreated pregnancy-related hypertensions. The severity of pregnancy-related hypertension is not primarily reflected in changes of fetal movement and acceleration behaviours, either. This means that the parameters presented are not suited to prognosticate the effects of pregnancy-related hypertension on the fetus a priori. The situation becomes quite different if in addition to pregnancy-related hypertension some intrauterine fetal growth retardation develops. In this case, the fetus indicates its impairment by increasingly impaired movement and heart rate activities as a consequence of chronic oxygen deficiency.

Female↗
PubMed1990

Time-dependent alterations in lipid metabolism during treatment with low-dose oral contraceptives.

The effect of sex steroids on lipid metabolism depends on the type and dose of the compounds, the route of administration, and the duration of treatment. Therefore the composition of an oral contraceptive determines the resultant effect on lipids and lipoproteins. During 12 months of treatment, the effects of two oral contraceptives containing 30 micrograms of ethinyl estradiol and 150 micrograms of desogestrel (EE/DG) or 75 micrograms of gestodene (EE/GSD) on 19 serum parameters of lipid metabolism were followed in 11 women each. There was no change in total cholesterol and phospholipids. Total triglyceride levels were significantly elevated only by EE/GSD. After 3 and 6 months of intake of both preparations, a transitory increase in the triglyceride content of very low-density lipoprotein and low-density lipoprotein and a decrease in low-density lipoprotein-phospholipids was observed. After 12 months, very low-density lipoprotein cholesterol, very low-density lipoprotein phospholipids, and apolipoprotein B were significantly elevated, whereas very low-density lipoprotein triglycerides and all components of low-density lipoprotein were unchanged. Most of the components of high-density lipoprotein (HDL) were increased as a result of a rise in HDL3 and apolipoprotein A2, whereas HDL2 and apolipoprotein A1 were not altered. There was no significant difference between the effects of the two preparations, although those of EE/GSD were mostly more pronounced. The increase in high-density lipoprotein, very low-density lipoprotein, and total triglycerides reflects a slight preponderance of the effect of the estrogen component. Because low-density lipoprotein cholesterol and total cholesterol were not changed, treatment with both formulations is in all probability not associated with an elevated risk of atherosclerosis.

Adolescent↗
PubMed1990

The evaluation of radioactive microsphere data: remarks on the use of the BMDP and SAS statistical software packages.

We investigated the suitability of BMDP and SAS as an integrated tool for the evaluation of regional blood flow data obtained from the radioactive microsphere technique. Both packages were applied to a recent study on muscle blood flow with a 3-factorial design. The organization of data and files, the strategy of data reduction, and the evaluation by means of statistical and graphical techniques are shown. The method may be applied to any microsphere study design. A considerable amount of time can be saved and data integrity may be improved. The statistical quality of the results may benefit from the broad spectrum of statistical tests available.

Algorithms↗
PubMed1990

Changes in lipid metabolism during 12 months of treatment with two oral contraceptives containing 30 micrograms ethinylestradiol and 75 micrograms gestodene or 150 micrograms desogestrel.

The effect of two oral contraceptives containing 30 micrograms ethinylestradiol + 75 micrograms gestodene (EE/GSD) or 30 micrograms ethinylestradiol + 150 micrograms desogestrel (EE/DG) upon serum lipids and lipoproteins were measured in 11 women each on days 1, 10, and 21 of the first, third, sixth, and twelfth treatment cycle and compared to the levels on days 1, 10, and 21 of the preceding control cycle. There was no change in total cholesterol (CH) and phospholipids (PL), while total triglycerides (TG) were significantly elevated only during treatment with EE/GSD. After 3 and 6 months of intake of both oral contraceptives, a transitory increase in the TG content of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL), and a decrease in LDL-PL was observed. After 12 months, VLDL-CH, VLDL-PL, and apolipoprotein B were significantly elevated, while VLDL-TG and all components of LDL were unchanged. Most of the components of high-density lipoprotein (HDL) were increased due to a rise in HDL3 and apolipoprotein A-II, while HDL2 and apolipoprotein A-I were not altered. There was no significant difference between the effects of the two preparations, although those of EE/GSD were mostly more pronounced. The time-dependent change in the effects of the oral contraceptives on various parameters of lipid metabolism demonstrates that the relevance of results of short-time studies may be questionable. There was also a significant alteration in some parameters between day 1 and 10 of the treatment cycles and a tendency to return to the pretreatment levels during the pill-free week, e.g., in total TG and in the PL component of VLDL, LDL and HDL. The increase in HDL, VLDL, and total TG reflects a slight preponderance of the effect of ethinylestradiol on lipid metabolism. The unchanged total CH and LDL-CH and the elevated HDL levels indicate that the risk of the development of atherosclerosis is in all probability not increased during treatment with both preparations.

Adolescent↗
PubMed1990

MIC-III--an integrated software package to support experiments using the radioactive microsphere technique.

MIC-III is a versatile program system to support gamma spectrometry data management and data collection for experiments using the radioactive microsphere technique. It is mainly written in PASCAL and running on a minicomputer. Hierarchical organ dissection schemes are used for unique classification and identification of samples. For each series of experiments, up to 12 different nuclides and up to 20 different organ dissection schemes can be handled simultaneously. Sample weights are collected on-line and sample radioactivities are measured automatically by gamma spectrometry under process control. The spectra with a resolution of 1022 channels are analyzed using a modified linear regression technique and a strategy to compensate for global spectrum shifts. The spectrum deconvolution algorithm was evaluated by calculating the recovery indices for known nuclide mixtures and compared to the stripping method, matrix method and a linear regression technique using window counts. Recovery values produced by MIC-III are better balanced than those of the other methods. MIC-III showed the smallest dispersion of the recovery index and exhibited least error accumulation in case of spectrum shift. MIC-III computes regional blood flow and arterio-venous shunt, and provides interfaces to customized programs or statistical software packages for further analysis. It has successfully been employed in more than 140 experiments.

Animals↗
PubMed1990

Outpatient treatment of adults with coexisting substance use and mental disorders.

This study examined the six-month and one-year treatment statuses of 118 patients admitted to an abstinence-oriented, outpatient facility serving dually disordered adults. Findings revealed that persons who have been underserved by the mental health and substance abuse fields can be engaged in treatment and will respond favorably to it. Overall, demographic characteristics, admission diagnoses, and past treatment history did not predict treatment outcomes. Rather, patients who participated more fully in treatment had better recoveries than did those who did not engage in treatment. In addition, patients who complied and responded to treatment during their first six months in treatment were more likely to comply and respond to treatment during the second six months of treatment. These results should encourage other clinicians to develop innovative services that meet the needs of dually disordered adults.

Adaptation, Psychological↗
PubMed1990

Properties and Activity Changes of Chlorogenic Acid:Glucaric Acid Caffeoyltransferase From Tomato (Lycopersicon esculentum).

A novel acyltransferase from cotyledons of tomato (Lycopersicon esculentum Mill.), which catalyzes the transfer of caffeic acid from chlorogenic acid (5-O-caffeoylquinic acid) to glucaric and galactaric acids, was purified with a 2400-fold enrichment and a 4% recovery. The enzyme showed specific activities (theoretical V(max) per milligram of protein) of 625 nanokatals (caffeoylglucaric acid formation) and 310 nanokatals (caffeoylgalactaric acid formation). On sodium dodecyl sulfate-polyacrylamide gel electrophoresis it gave an apparent M(r) of 40,000, identical to the value obtained by gel filtration column chromatography. Highest activity was found at pH 5.7, which was constant over a range of 20 to 120 millimolar K-phosphate. The isoelectric point of the enzyme was at pH 5.75. The reaction temperature optimum was at 38 degrees C and the apparent energy of activation was calculated to be 57 kilojoules per mole. The apparent K(m) values were 0.4 millimolar for glucaric acid, 1.7 millimolar for galactaric acid, and with both acceptors as second substrates 20 millimolar for chlorogenic acid. The relative ratio of the V(max)/K(m) values for glucaric acid and galactaric acid was found to be 100:12. Substrate-competition experiments support the conclusion that one single enzyme is responsible for both the glucaric and galactaric acid ester formation with marked preference for glucaric acid. It is proposed that the enzyme be called chlorogenic acid:glucaric acid O-caffeoyltransferase (EC 2.3.1.-). The three caffeic acid-dependent enzyme activities involved in the formation of the glucaric and galactaric acid esters, the chlorogenic acid:glucaric acid caffeoyltransferase as the key activity as well as the caffeic acid:CoA ligase and the caffeoyl-CoA:quinic acid caffeoyltransferase as the preceding activities, were determined. The time course of changes in these activities were followed during development of the seedling in the cotyledons and growth of the young plant in the first and second leaf. The results from tomato seedlings suggest a sequential appearance of these enzymes.

Journal Article↗
PubMed1990

[Phenotyping of apolipoprotein E: immunoblotting after isoelectric focusing in immobilized pH gradients].

Apolipoprotein E is a major ligand for cellular lipoprotein receptors and plays an important role in the catabolism of triglyceride-rich lipoproteins. The polymorphism of apo E is associated with familial dysbetalipoproteinemia, LDL-cholesterol, and cardiovascular risk. In this report a method for the analysis of apo E isoforms in immobilized pH gradients is presented that does not require isolation apo E containing lipoproteins by ultracentrifugation.

Apolipoproteins E↗
PubMed1990

[Fast lipoprotein chromatography: a new method for determining plasma lipoproteins].

Fast Lipoprotein Chromatography (FLPC) is a novel method for the quantitation of lipoprotein fractions. Plasma proteins are separated by fast flow gel filtration and lipoproteins are detected after post-column derivatization with an enzymatic cholesterol reagent. FLPC resolves VLDL, LDL, and HDL. Coefficients of variation for determinations of VLDL-, LDL-, and HDL-cholesterol are 5.8%, 2.0%, and 1.9%, respectively. Comparison of FLPC with a combined ultracentrifugation and precipitation method obtained correlation coefficients of 0.983, 0.973, and 0.941 for VLDL-C, LDL-C, and HDL-C, respectively.

Apolipoprotein A-I↗