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Biomedical subjects

R Ritter

Publications and source records attributed to R Ritter.

At least 19 recordsLinked to original sources
PubMed1992

Low-dose near-celiac arterial cholecystokinin suppresses food intake in rats.

Exogenous cholecystokinin (CCK) suppresses food intake by acting on vagal sensory neurons. However, CCK doses used in behavioral experiments are generally much larger than those necessary to produce electrophysiological changes in vagal afferents. We made automated measurements of liquid food intake before, during, and after infusion of low doses of CCK octapeptide (CCK-8) through a chronic aortic catheter with its tip seated just above the celiac juncture. In parallel experiments, we made similar infusions while collecting blood from the hepatic portal and jugular veins for CCK assay. Injection of 10, 30, 50, and 70 pmol of CCK-8 suppressed feeding in a dose-dependent manner beginning 1 min postinfusion. The lowest dose to produce statistically significant suppression of preinfusion intake was 30 pmol. Infusion of the same CCK-8 doses into the jugular vein did not suppress feeding. Near-celiac injection of 30 pmol of CCK-8 produced systemic plasma CCK concentrations averaging 6.5 +/- 1 pM compared with less than 1 pM after saline injection. These findings show that exogenous CCK, by acting on tissues perfused by the celiac artery, can suppress feeding at doses that 1) are similar to those producing effects on the firing of vagal neurons and 2) do not increase plasma CCK concentrations above postprandial levels.

Animals↗
PubMed1989

[Studies of solutions with various branched-chain amino acid contents on protein metabolism in the postoperative period. 1. A 15N tracer kinetic animal model for evaluating the effect of parenteral amino acid administration on nitrogen metabolism].

We were able to estimate nitrogen or protein metabolism on the basis of a 15N metabolic model that delivered a high amount of data during a parenteral nutrition period over 72 h. We describe the basic principles of the necessary N or 15N-analyses in blood, as well as in sera, in urine, in tissues of selected organs and in hepatocytes. This 15N-metabolic model allows the estimation of the utilization of amino acid infusion solutions. Because of the great similarity of parameters of the N or protein turnover between man and pig it is possible to provide relevant information for the clinical practice regarding amino acid infusion solutions.

Alanine Transaminase↗
PubMed1988

Evaluation of protein metabolism in clinical practice.

The application of stable isotopes creates further possibilities for our understanding of the metabolism. New concepts especially for non-invasive diagnostic procedures could be developed. An important step in our research program was the performing of a 1-year experiment on a volunteer. On the basis of a 10-pool model we received a lot of informations. Based on this knowledge we developed 2 simplified methods for calculating whole body protein turnover. Knowing the problems with whole body protein calculations we intensified our intentions for determining the protein enrichment in organs and isolated cells (hepatocytes), estimating at the same time the precursor pool in the cells. Of special importance was an extensive study, wherein all those 15N-estimations were performed we are able to do up to now. We calculated whole body protein, but especially we studied the enrichment of the cellular protein fractions in hepatocytes, of plasmaproteins, and of the intracellular precursor pool. This study is the base for further tracer investigations.

Animals↗
PubMed1988

Paget's disease with extensive involvement of the female genital tract initially detected by cervical cytosmear.

A 78-year-old woman with extramammary Paget's disease presented with vaginal bleeding and vulvar pruritus. Paget's cells were demonstrated initially in a cervical cytosmear and, subsequently, in the epithelia of the vagina and cervix, in addition to those of the vulva, periurethral area, and perineum. Such extensive intraepithelial spread of Paget's disease in the genital tract has rarely been reported previously. This is the first case, to our knowledge, in which the cells of cervicovaginal Paget's disease were detected by Papanicolaou smear.

Aged↗
PubMed1987

[Value of various amino acid mixtures for the treatment of chronic liver damage].

A reproducible liver lesion was caused in 28 pigs by intermittent, intraperitoneal administration of thioacetamide. The morphological degree of the liver lesion was checked by histological investigations (material drawn from the liver by biopsy). During a 3-day infusion period a so-called liver solution (Aminofusin hepar) was given to one group of animals, a normal solution (Infesol) to a second group, and only an electrolyte infusion solution under oral nutrition ad libitum to a third one. The solutions were labelled with (15N) glycine. The amounts of total N, total 15N, 15N with single non-protein fractions, a number of enzymes of 15N incorporated into the liver protein were measured in urine, and the following points were established: 1. The catabolic situation of metabolism is eliminated both by the so-called normal solution and the specific amino acid solution. The two mixtures of L-amino acids thus have a nutritive effect. 2. The toxic liver lesion is an indication for parenteral nutrition. Oral nutrition alone is not sufficient. 3. The so-called liver solution influences the liver metabolism of the protracted liver lesion more than the so-called normal solution does, and considerably more than an electrolyte infusion solution under oral nutrition ad libitum.

Amino Acids↗
PubMed1986

[The intravenous 15N metabolism test in assessing the effect of parenteral feeding on protein synthesis].

It is possible to investigate the influence of parenteral applicated L-amino acids on protein metabolism of whole organism by the help of 15N-tracer technique in this paper described. We can determine the utilization of nitrogen parenteral applicated quantitatively. On the basis of graphical methods the protein synthesis rate can be calculated. We get this from mathematical models, based on 3-pool-model. The calculation bases on 15N-elimination in urine after intravenous infusion of 15N labeled amino acids solution during the time of 24 h (endproduct method). We describe 3 graphical methods, using the so-called values of plateau of cumulative 15N-excess amount (96 h) (plateau method A) or 15N abundance after 24 h (plateau method B) and the slope of the curve of 15N excess, amount at 24 h ('slope' method). By the help of these methods the therapeutical nutritive conceptions can be evaluated.

Amino Acids↗
PubMed1982

The influence of the rate of electrical stimulation on the effects of the Anemonia sulcata Toxin ATX II in guinea pig papillary muscle.

In guinea pig papillary muscle, the rate of electrical stimulation (0.1-2 Hz) strongly influenced the effects of the Anemonia sulcata toxin ATX II on action potential duration (APD) and contractile force. In the concentration range studied (10-8-10-7 M), ATX II always produced a larger prolongation in APD at low rates of stimulation. At 0.1 Hz there was a temporal dissociation between the onset of the APD-prolonging and the positive inotropic effect. However, under equilibrium conditions there was a positive relationship between the APD expressed as a fraction of the time during which the membrane was depolarized, and the contractile force irrespective of the change in experimental conditions being variation of stimulation frequency or the addition of ATX II. The results suggest that the positive inotropic effects of both ATX II and increased stimulation frequency could be induced by a similar mechanism, e.g. an increase in sodium of the heart muscle.

Action Potentials↗
PubMed1978

[Sport and prolongation of life (author's transl)].

In a retrospective study a group of 80-year-old men (114) were compared with regard to their living habits with a group of men from the same firm (131) who had died before the age of 65. The aim of the study was to present factors which could possibly affect the limitation of life expectancy. By means of electronic data processing the findings of the investigation and historical data (family history, personal history, risk factors, physical activity, occupational and social status) were evaluated and possible correlations looked for. The cause of death was particularly included in the interpretation. The risk factors of greatest importance were: cigarette smoking, adiposity, little physical activity.

Humans↗
PubMed1978

[The position of scintigraphy in traumatology].

A report on the findings of skeletal scintigraphy in 80 cases of traumatic bone lesions is discussed. After a short survey on the physiological process in the activity ensilage, the assertion of the scintigraphy is compared to the X-ray. The indication which has been approved in practice is discussed and described. In correct indication scintigraphy is a valuable diagnostic measure and it may influence the procedure.

Adult↗
PubMed1978

[Scintigraphy in the diagnosis of osteitis].

The report on the experience with skeletal scintigraphy in case of osteitis discusses the clinical use of this method. It is shown that with correct indication scintigraphy can furnish early diagnosis and in many cases additional valuable information.

Adult↗
PubMed1976

Hemihypertrophy in a boy with renal polycystic disease: varied patterns of presentation of renal polycystic disease in his family.

Hemihypertrophy is a condition that has been described in association with a variety of other malformations and diseases; quite often these have had a renal origin. -It is the purpose of this paper to record and discuss the occurrence of polycystic disease in a family, to note that the disease was manifest as either the "adult" or the "infantile" form, and detail the fact that one member of the family who had infantile type polycystic disease also had hemihypertrophy. -The pattern of inheritance of renal polycystic disease, its age at presentation and the variation in the boy of its manifestation with the passage of time are discussed. The need for caution in offering a prognosis and genetic counselling is stressed.

Child↗
PubMed1976

[Results of bleomycin therapy in recurrent head and neck tumors (author's transl)].

40 patients with previously treated recurrent head and neck carcinomas have been treated with Bleomycin. The total dose of drug administered ranged from 360-600 mg. In three patients, treatment had to be interrupted because of severe side effects of the drug. Temporary complete disappearance of tumor occurred in three patients, whereas incomplete tumor regression briefly occurred in one third of those patients treated. Survival time for all patients averaged three months. A possible immunosuppressive effect of Bleomycin is also discussed, as based on clinical observations noted in one of the patients treated.

Bleomycin↗