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Biomedical subjects

N Wagner

Publications and source records attributed to N Wagner.

At least 73 records · Page 4Linked to original sources
PubMed1990

The previous visual field: effects of lateralization and response accuracy on current performance.

The accuracy of performance in identifying syllables flashed to the RVF (right visual field) or LVF (left visual field) was strongly affected by the lateralization of and response accuracy for the previous stimulus, presented 10-20 sec earlier. For both the LVF and RVF, performance was better on Pre-LVF trials (previous stimulus in LVF) than on Pre-RVF trials (previous stimulus in RVF). The Pre-LVF advantage was the same in subjects with a strong RVF advantage and those with no asymmetry. Their performance was better when a previous stimulus had received adequate attention for correct encoding (Pre-Correct) than when it had not (Pre-Wrong), for both fields on Pre-LVF trials and the LVF, but not RVF, on Pre-RVF trials. Relations are discussed in terms of the capacities and properties of the RH (right hemisphere) and LH (left hemisphere) cerebral arousal systems.

Adult↗
PubMed1990

Behavioral and subjective effects of ethanol: relationship to cerebral metabolism using PET.

This study examined the effects of ethanol on regional cerebral metabolic rate using positron emission tomography (PET). The study explored the relationship between the mood-altering effects of ethanol and its effects on regional cerebral glucose utilization (CMRglu) in eight healthy male volunteers. In the first phase of the study, the subjects participated in a behavioral preference procedure conducted in a recreational environment to determine their responses to ethanol (0.5 g/kg) in a naturalistic setting. They then participated in three PET sessions, receiving at three to seven day intervals, in counterbalanced order, placebo, 0.5 g/kg or 0.8 g/kg ethanol. PET scans were conducted using a PETT-VI scanner with F-18-2-fluoro-2-deoxyglucose (FDG) as the tracer. The mood-altering effects of ethanol were measured in both the naturalistic and the PET phases of the study. Ethanol produced comparable effects on mood in the naturalistic and the PET settings (i.e., increases in positive mood). The lower dose of ethanol produced variable effects on whole brain and regional CMRglu across subjects. There was some suggestion that certain regional metabolic changes after ethanol were correlated with subjective responses to the drug. The higher dose of ethanol decreased whole brain CMRglu in most subjects. All regions were affected about equally. It was concluded that the mood-altering effects of ethanol are not related in a simple manner to regional changes in CMRglu.

Adult↗
PubMed1990

HIV-1 infection in a cohort of haemophilic patients.

The course of HIV infection in 53 haemophilic patients aged 5-20 years was evaluated by clinical examination and laboratory tests. During the evaluation time (median 30 months) two patients died of AIDS and 32 patients (60%) deteriorated when assessed by the Brodt-Helm classification. Nineteen patients (37%) had decreased absolute helper cell counts (less than 500 CD4 positive cells/microliters), and 45 patients (87%) had reduced helper cell to lymphocyte ratios (less than 0.35). HIV-1 was isolated from peripheral lymphocytes in 29 of 46 patients. As the disease progressed the number of positive viral cultures increased. Considerable progression of the HIV infection was seen in haemophilic children and adolescents during the median evaluation period of 30 months. The transition from symptomless HIV infection to immunodeficiency was easily recognised. A lowered ratio of helper cells to lymphocytes seems to be a useful marker of the beginning of the deterioration of the immune system.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Transferrin is an autocrine growth factor secreted by Reuber H-35 cells in serum-free culture.

We have previously reported that Reuber H-35 rat hepatoma cells secrete an autocrine growth-stimulating activity in serum-free culture. To characterize this activity, conditioned serum-free medium from dense H-35 donor cultures was collected in the absence and presence of [35S]methionine. A 1:4 dilution of conditioned medium into fresh serum-free medium resulted in an increase in mean H-35 cell numbers per assay dish from 1.59 +/- 0.12 X 10(5) to 3.35 +/- 0.34 X 10(5) after 44 h of incubation. Control, unconditioned medium, resulted in significantly (P less than 0.05) less growth (2.14 +/- 0.41 X 10(5) cells per dish). Trypsin digestion eliminated the growth-promoting effect of conditioned medium but had no effect on unconditioned medium. Dialysis did not diminish the growth-promoting activity of conditioned medium. The immunoprecipitate of [35S]methionine-containing conditioned medium with antisera against rat serum transferrin contained a dominant radioactive doublet of molecular weight equal to purified rat serum transferrin. A rat transferrin radioimmunoassay was devised and used to quantitate that 29.1 +/- 1.2 ng of transferrin was secreted per 10(6) cells per hour in serum-free culture. Addition of antitransferrin antibody resulted in a significant (P less than 0.025) decrease in H-35 cell growth after 48 h. Thus, a portion of the autocrine growth-promoting activity secreted by H-35 cells into serum-free culture is due to transferrin.

Animals↗
PubMed1988

Growth of H-35 rat hepatoma cells in unsupplemented serum-free media: effect of transferrin, insulin and cell density.

Serum-free tissue culture medium consisting of a 1:1 mixture of Dulbecco's modified Eagle's medium (DMEM) and Ham's F12 medium is herein shown to support growth of Reuber H-35 cells over several days in culture. Cells were initially plated in serum containing DMEM medium for 3 h. After cell attachment, serum is removed and replaced with a serum-free 1:1 mixture of these two commercially available tissue culture media. The doubling time of cell growth in this unsupplemented serum-free medium was 46 h in lightly plated cultures over the first 5 d. The presence of transferrin (5 micrograms/ml) and insulin (3.3 nM) results in a cell doubling time of 17 h, which equaled the growth rate in medium containing 10% fetal bovine serum. In the absence of transferrin, growth rates in serum-free medium were correlated with the cell density of cultures. Conditioned medium from dense, serum-free cultures has growth-stimulating activity in recipient lightly plated cultures. This simple, serum-free culture medium will facilitate studies on the growth regulation of H-35 rat hepatoma cells.

Animals↗
PubMed1987

Coreconstitution of bacterial ATP synthase with monomeric bacteriorhodopsin into liposomes. A comparison between the efficiency of monomeric bacteriorhodopsin and purple membrane patches in coreconstitution experiments.

The conditions for coreconstitution of a bacterial ATP synthase and bacteriorhodopsin into lecithin liposomes and for light driven ATP synthesis have been optimized. A rate of maximally 280 nmol ATP min-1 mg ATP synthase-1 was achieved with monomerized bacteriorhodopsin compared with a rate of up to 45 nmol ATP min-1 mg-1 found for proteoliposomes containing bacteriorhodopsin in the form of purple membrane patches. The different rates are explained by the finding that monomeric bacteriorhodopsin is more homogeneously distributed among the liposomes than the purple membrane patches. The final activities depended on both the purification method for the two proteins and the coreconstitution procedure. Furthermore, the ratio (lipid to bacteriorhodopsin to ATP synthase) could be optimized. Light-driven ATP synthesis depends also on the type of detergent used. The best result was obtained by deoxycholate. Also the relationship between proton translocation (by bacteriorhodopsin) and ATP synthesis activity was measured. A constant H+/ATP ratio was found at higher light intensities. This ratio increased strongly at lower light intensities.

Bacteriorhodopsins↗
PubMed1984

Handwriting posture, visuomotor integration, and lateralized reaction-time parameters.

On a simple manual reaction-time (RT) task to lateralized visual signals, right-handers and left-handers with the noninverted handwriting posture (RN and LN subjects, respectively) were faster and more consistent when the signal and response hand were homolateral as compared to heterolateral, but left-handers with the inverted handwriting posture (LI subjects) were not. For LI subjects, there was no speed difference for homolateral and heterolateral hand-signal combinations, and there was a clear and significant heterolateral superiority for response consistency. In agreement with suggestions of others, we believe that the anomalous response pattern of LI subjects is likely to be due to a disorder of visuomotor integration and cannot be attributed to reliance on uncrossed motor pathways.

Adolescent↗
PubMed1983

Cataract formation in newborn rats from feeding a liquid protein diet during gestation.

Liquid protein diets have been widely used in the United States to control weight gain. Pregnant rats were fed a standard casein diet in which liquid protein was substituted for the protein portion; all other necessary nutrients were supplied. The average incidence of cataracts in the offspring from mothers fed liquid protein was 25%. Offspring born with cataracts were successfully raised. The results suggest that nutrition may play an important role in cataract formation in newborns, and that the use of liquid protein during pregnancy may be related to ocular abnormalities in the offspring.

Animals↗
PubMed1983

Significance of biogenic amines for opioid-induced locomotor activity in rats.

The effect of the opioid levorphanol on locomotor activity was investigated in rats treated with p-chlorophenylalanine (PCPA) or 6-hydroxydopamine (6-OHDA). Acute oral administration of 10 or 30 mg/kg levorphanol induces a time- and dose-dependent alteration in motility. Ingestion of 10 mg/kg levorphanol in rats with an intact biogenic amine content results in an increase of locomotion for 180 min followed by a longer lasting, small but significant, reduction of motor activity. The course of motility after 30 mg/kg is similar to that after 10 mg/kg, but the initial peak appears after a 3-h delay. In 5-hydroxytryptamine (5-HT)-deficient rats, the first excitation of motility is enhanced and its subsequent depression intensified. After administration 30 mg/kg a general reduction in motor activity occurs. The effect of 10 mg/kg levorphanol after 6-OHDA treatment is on a lower level, similar to that of rats with intact amine content. After 30 mg/kg levorphanol an immediate and longer lasting increase in activity appears. Chronic ingestion of about 40 mg/levorphanol/kg per day enhances the total amount of activity in normal rats as well as in animals with catecholamine (CA) depletion, but not in those treated with PCPA. In all cases, withdrawal of the opioid results in a reduction of activity below that of control levels.

Animals↗
PubMed1982

[Fungal infestation of gastroduodenal ulcers: incidence and significance (author's transl)].

In a prospective study of 132 cases of gastroduodenal ulcer, proven by endoscopic biopsy, there were 59 in which fungi were cultered (44.7%). There was no significant difference in incidence between gastric ulcer (46.2%) and duodenal ulcer (42.6%), or between benign and malignant gastric ulcer (47.2 and 42.1%, respectively). Most of the fungi were yeasts of the genus Candida and Torulopsis. The mycel phase was demonstrable only in the native or histological preparation (16.7% [native] and 10.6% [histological] positive findings). In all those cases in which pseudomycels were demonstrated the culture count was especially high (more than 20 colonies). In most of these there was an additional disease which may be associated with immunological insufficiency (e.g. diabetes, chronic alcoholism, malignoma). The presence of pseudomycelia or more than 20 colonies in the culture from gastroduodenal ulcers are thus less of a pointer as to whether the local lesion is benign or malignant than to a general weakening of the organism's defence mechanisms.

Adult↗
PubMed1975

Functional changes in platelets during extracorporeal circulation.

An in vitro trauma test was conducted to determine the effects of extracorporeal circulation on platelet count and function. Fresh human blood was circulated in two identical in vitro circuits for six hours at a rate of 500 ml per minute (500 recirculations). One circuit included a G.E.--Peirce membrane lung and the other was a control. Platelet aggregation induced by adenosine diphosphate (ADP), epinephrine, or collagen was studied before and after six hours of perfusion. No important drop in platelet count occurred in the control circuit (Control-C) following bypass, but there was a 20% drop for the lung circuit (Lung-C). Platelet aggregation was reduced by about 30% for the control circuit and 65% for the lung circuit. The large decrease in platelet function accompanied by only a moderate decrease in platelet count is discussed in terms of loss of the youngest and most active platelets, platelet inhibition due to ADP released by red blood cell lysis, and platelet trauma.

Adenosine Diphosphate↗