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Biomedical subjects

G Gerber

Publications and source records attributed to G Gerber.

At least 55 records · Page 3Linked to original sources
PubMed1991

Changes of nucleotide patterns in liver, muscle and blood during the growth of Ehrlich ascites cells: application of the reversed-phase and ion-pair reversed-phase high-performance liquid chromatography with radial compression column.

The pool of purine compounds was analysed in liver, skeletal muscle and blood of mice during the growth of Ehrlich ascites tumour cells. Three fast isocratic high-performance liquid chromatographic methods were used. (1) Determination of nucleotides by an isocratic ion-pair reversed-phase chromatography with a 10 mM ammonium phosphate buffer containing acetonitrile and tetrabutylammonium phosphate. (2) Separation of nucleosides and nucleobases in cell extracts by a reversed-phase system with methanol and 50 mM potassium phosphate buffer as eluent. (3) Nucleosides and nucleobases in body fluids were analysed by a reversed-phase system with 10 mM potassium phosphate containing methanol. These methods allow the rapid determination of purine compounds in small biological samples from various cell types and body fluids, with high accuracy and sensitivity. The pool of cellular nucleotides increased during the exponential phase of tumour growth. Adenosine accumulated significantly in all tissues in the stationary phase of tumour growth.

Animals↗
PubMed1991

Assessment of value of routine bone scans in patients with newly diagnosed prostate cancer.

The value of routine bone scans as a staging procedure was assessed in patients with newly diagnosed prostate cancer. Records from 277 patients were reviewed retrospectively to determine the serum acid and alkaline phosphatases, the presence or absence of bone pain, and the results of bone scans and other radiographic studies at the time of initial diagnosis. We determined the sensitivity and specificity of an abnormal acid phosphatase, an abnormal alkaline phosphatase, and the presence of bone pain used in combination for assessing bone metastases. If at least one of these three parameters was present, the sensitivity was 97 percent, whereas if all three tests were normal, the specificity was 78 percent. The negative predictive value for all three tests combined is 99 percent. These results suggest that a routine bone scan to stage patients with newly diagnosed prostate cancer who have no bone pain and normal acid and alkaline phosphatases may not be warranted in all cases.

Acid Phosphatase↗
PubMed1991

Superoxide dismutase promotes ATP and GTP restoration of rat small intestine during postischaemic reperfusion.

The small intestine of rats was prepared according to a procedure which is taken for preservation and transplantation in clinical practice. The blood supply of the rat intestine was completely interrupted for 30 min in situ. During this period the lumen of the intestine was rinsed with Ringer-lactate solution. This ischaemic period was followed by 10 min of reperfusion. As a result a decrease in ATP, and GTP concentrations, and of the total adenine nucleotide content during the preservation period occurred. In animals pretreated with superoxide dismutase (i.v. application; superoxide dismutase preparation from human erythrocytes) an accelerated restoration of nucleotide concentrations during the reperfusion period was observed. From the beneficial effect of superoxide dismutase it can be concluded, that there is a considerable formation of active species of oxygen which disturb the energy generation by the mitochondrial respiratory chain during ischaemia/re-oxygenation.

Adenine Nucleotides↗
PubMed1991

Characterization of a hexammineruthenium-stimulated external NADH oxidase from rat liver mitochondria.

The existence of an external hexammineruthenium-stimulated NADH oxidase in rat liver mitochondria is postulated. This enzyme is localized on the outer surface of the inner mitochondrial membrane, is specific for NADH and requires oxygen. The apparent affinity of the enzyme for NADH amounts to about 4 microM. Furthermore, the enzyme is characterized by an alkaline pH optimum and a linear Arrhenius plot (14 kJ/mol). The electron transfer from NADH to oxygen is not linked with the respiratory chain but is connected with the formation of superoxide radicals.

Animals↗
PubMed1990

Aldehyde and nucleotide separations by high-performance liquid chromatography. Application to phenylhydrazine-induced damage of erythrocytes and reticulocytes.

High-performance liquid chromatographic (HPLC) techniques were used for the determination of aldehydes as lipid peroxidation products and of nucleotide concentrations in rabbit red blood cells exposed to phenylhydrazine hydrochloride. Aldehydes were determined by derivatization to dinitrophenylhydrazones, followed by thin-layer chromatographic and HPLC separation with methanol-water on an ODS column. Nucleotides and their derivatives were measured by ion-pair reversed-phase HPLC gradient elution with 10 mM ammonium phosphate buffer containing 2 mM tetrabutylammonium phosphate on ODS columns. The sensitivity of mature erythrocytes was compared with that of reticulocytes against the toxicological effects of phenylhydrazine. For both cell types an increase in aldehyde concentrations, especially of 4-hydroxynonenal, and a decline in both energy-rich nucleoside triphosphate and NAD+ were demonstrated.

Aldehydes↗
PubMed1990

The catabolism of endogenous adenine nucleotides in rat liver mitochondria.

The degradation of intramitochondrial adenine nucleotides to nucleosides and bases was investigated by incubating isolated rat liver mitochondria at 37 degrees C under non-phosphorylating conditions in the presence of oligomycin and carboxyatractyloside. Within 30 min the adenine nucleotides were degraded by about 25 per cent. The main products formed were adenosine and inosine the contents of which increased five- to sevenfold. Compartmentation studies revealed that about 50 to 60 per cent of the adenosine formed remained inside the organelles whereas inosine was almost completely released into the surrounding medium. Outside the mitochondria only very small amounts of adenine nucleotides were detected. Similar incubations in the presence of [14C]-adenosine yielded no [14C]-inosine ruling out extramitochondrial adenosine deamination. It is concluded that endogenous adenine nucleotides can be degraded in mitochondria via AMP dephosphorylation and subsequent adenosine deamination. A purine nucleoside transport system mediating at least the efflux of inosine from the mitochondria is suggested.

Adenine Nucleotides↗
PubMed1990

Sensing, feeling, thinking. A development model for therapy and rehabilitation.

1. Holding the view that the whole is more than the sum of its parts opens up the possibility of integrating psychic and physical peculiarities. 2. Under the preeminence of wholeness, therapeutic methods are not exhausted in a one-sided promotion of intellectual and bodily functions. 3. By sensitizing and differentiating the sensory perception, the direct sensing experience is deepened, broadened and enriched. 4. If the physically sensed is recalled, feelings develop and grow deeper via imagery ideas. 5. It is only when the sensed physicalness and felt imagery are verbalized that speech and thought are in the true sense of word lively, not representing a set, stereotyped pattern. 6. If that which is possible can be developed and integrated, than that which is peculiar loses some of its importance, thus no longer standing for the whole but rather becoming part of the whole.

Emotions↗
PubMed1990

The problems of the employment of child and adolescent psychotherapeutical care.

We attempted to clarify the questions as to which variables were important for the acceptance or nonacceptance of a psychotherapy offer to the patients of our department. 1. We attempted to interpret some of the interpersonal variables hermeneutically: pressure of suffering and ability to suffer. We reflected these concepts as regards their ontogenesis and their significance for the initial contact with the therapist and the later compliance with the doctor-patient-relationship. 2. Other variables could be dealt with empirically. A group of patients whose psychotherapy was offered within one year of their initial contact with the clinic was examined. Here it was a question of 106 children and adolescents, 62 of these boys and 40 girls. No statistically significant influence upon the acceptance or refusal of an offer of therapy appeared in the variables--age and sex of the patients; distance between place of residence and clinic; the mother's occupation; psychiatric illnesses in relatives. On the other hand, a statistically significant influence is exercised by the variables--time interval between offer of therapy and its acceptance; therapy with psychopharmaceuticals at the same time; necessity of a depth psychologically-oriented individual therapy.

Adolescent↗
PubMed1990

Long term effects of monthly low dose whole body irradiation on the glutathione status and thiobarbituric acid-reactive substances in different organs of male Wistar rats.

Male Wistar-H-rats were exposed monthly to a 60cobalt-source low dose whole body irradiation (0.25 Gy, total dose: 4.5 Gy). The glutathione disulphide:total glutathione ratio, the concentration of thiobarbituric acid-reactive substances and the activities of glutathione peroxidase and glutathione transferase in eight different organs and blood were analysed. The low dose irradiation is accompanied by distinct peroxidative changes in organs. These oxidative loadings occur in the small intestine, the spleen and the kidneys. The measurements of glutathione status and of thiobarbituric acid-reactive substances are proposed as sensitive parameters for low dose radiation induced changes.

Animals↗
PubMed1990

[Metabolic pool of purine compounds in erythrocytes of mice during growth of transplanted tumors].

The pattern of purine derivatives was studied in the erythrocytes of C3HA and ICR mice during Hepatoma 22 and Ehrlich ascites tumor cells growth. Host erythrocytes purine nucleotides, nucleosides and bases were affected by the implanted tumors. The results indicated that the host erythrocytes markedly concentrated adenine and guanine nucleotides on the 5th and 11th-12th day of tumor growth. By contrast, content of nucleosides and bases were sharply decreased during the log growth phase (5th day) with the restoring of these precursors within the 11th-12th day (plateau phase). These observations indicate that aspects of the purine compounds metabolism in host erythrocytes are linked with tumor development.

Adenine Nucleotides↗