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J P Striebel

Publications and source records attributed to J P Striebel.

At least 19 recordsLinked to original sources
PubMed1996

Hyperammonemia-induced depletion of glutamate and branched-chain amino acids in muscle and plasma.

BACKGROUND/AIMS: Exogenous hyperammonemia is known to decrease the plasma levels of branched-chain amino acids (BCAA). To investigate whether changes in intracellular amino acid concentrations of muscle are associated with and may, at least in part, mediate this effect, experiments were carried out on a total of 60 male Wistar rats. METHODS: Five groups were formed in a randomized manner. Group A: no treatment; groups B1 and B2: 2-hour and 6-hour continuous central-venous infusions, respectively, of sodium salts; groups C1 and C2: 2-hour and 6-hour infusions of ammonium salts. We obtained venous blood samples and muscle biopsies. Plasma ammonia, whole blood glucose, serum insulin, blood pH, and amino acids in plasma as well as in the intracellular water of muscle were measured. RESULTS: As compared with control group A, groups C1 and C2 displayed a 3.3- and a 4-fold increase, respectively, in the plasma ammonium concentration. Regarding insulin, the ammonium-infused rats were similar to group A but not to the sodium-infused B groups, which had significantly lower insulin concentrations. Administering ammonium brought about a decline in BCAA concentrations in plasma after 2 hours and in muscle after 6 hours. The ammonium-induced fall in intracellular BCAA values was preceded by an increase of glutamine as well as by a decrease of glutamate and alanine in both plasma and muscle. CONCLUSIONS: It is pointed out that the inter-group differences in serum insulin, although possibly accounting for some of the findings, can by no means explain the entire pattern of amino acid concentrations seen after the ammonium infusions. Instead, our results agree with the hypothesis that hyperammonemia indirectly lowers the plasma levels of BCAA by stimulating glutamine synthesis, thus reducing the intracellular glutamate pool, which is likely to be restored, at least in part, by an intensified BCAA transamination. Clarification is needed as to whether carbon skeletons derived from valine and isoleucine additionally contribute to replenishing the glutamate pool.

Alanine↗
PubMed1990

[Peripheral vein requirement-adjusted parenteral feeding: renaissance of maltose?].

A requirement-adapted peripheral-venous parenteral nutrition was developed by exchanging the conventional carbohydrates like glucose, etc., for disaccharide maltose in combination with a fat emulsion (650 mosm/l; 2,000 kcal). In a clinical randomised study, we compared this nutrition regimen with a common requirement-adapted parenteral nutrition regimen, which was applicated by central-venous catheter (2,000 mosm/l; 2,000 kcal). All results, including the results of tracer-investigations with the strable isotope 13C-leucine, showed no metabolic difference between these two nutrition regimens.

Blood Glucose↗
PubMed1990

[Perioperative myocardial ischemia in patients with peripheral arterial occlusive diseases].

Patients with peripheral vascular disease (PVD) often have coronary artery disease (CAD) which means an increased risk during anesthesia. The prevalence of CAD is nearly 50% among such patients. Owing to claudication, diagnostic stress tests can rarely be performed in PVD patients. In order to evaluate the frequency of transient perioperative myocardial ischemia, Holter monitoring was performed in 30 consecutive PVD patients with ASA II-III and AVK scale (Fontaine) II-IV who were undergoing femoropopliteal bypass surgery. Patients who had left bundle branch block and left ventricular hypertrophy or were taking digitalis medication were excluded from Holter monitoring. The ST-segment analysis of the frequency modulated recordings (n = 19) revealed episodes of myocardial ischemia in 26% of the patients. Most (75%) of the episodes occurred preoperatively, and 25%, during or after the anesthesia or during preparation for it. Risk factors for CAD were more often found in patients with ST segment alterations than in patients without ST segment deviations, even though the preoperative antianginal medication administered was comparable in the two subgroups. It is concluded that in a considerable subset of PVD patients silent myocardial ischemia occurs, which can be related to the different perioperative intervals by means of ST segment analyses of Holter recordings. The ST segment may allow a better insight into the cardiac state of PVD patients. Further studies are necessary in larger populations to test our suspicion.

Aged↗
PubMed1989

Intra- and extracellular amino acid concentrations in portacaval-shunted rabbits. Role of hyperammonemia and effects of branched-chain amino acid-enriched parenteral nutrition.

Intra- and extracellular amino acid concentrations were measured in rabbits in order to elucidate the possible role of hyperammonemia in lowering the postabsorptive plasma levels of branched-chain amino acids (BCAA) and to assess the effects of BCAA-enriched total parenteral nutrition (TPN) on the amino acid pattern of muscle. The pathophysiological part of this paper deals with portacaval anastomosis (PCA) and is aimed at substantiating or rejecting our hypothesis that excessive ammonia-by stimulating glutamine synthesis-reduces the intracellular glutamate pool which is then restored, at least in part, by an intensified BCAA degradation. Regarding infusion therapy, we were mainly interested in whether an amino acid solution adapted to the metabolism in liver cirrhosis causes an accumulation of BCAA in muscle or modifies the intracellular content of glutamate and glutamine. Eighteen rabbits did not undergo surgery and served as controls (group A), while 30 were given a portacaval end-to-side anastomosis (group B). Two weeks after creating the PCA, venous blood samples were taken and muscle biopsies (Bergström's technique) were performed postabsorptively. An 18-h TPN was then started, the regimen administered included dextrose, fat and, in addition, either a conventional (group B1, n = 15) or an adapted amino acid solution (group B2, n = 15). We obtained second blood specimens and muscle biopsies at the end of the infusion period. With the control animals, the same time schedule for blood sampling and muscle biopsies was followed. Fourteen days after the operation, the PCA rabbits displayed a mean plasma ammonia level 5.1 times higher than that measured in the controls (p less than or equal to 0.001). Conventional blood chemistry did not reveal any impairment of liver cell integrity or over-all hepatic function, whereas the nutritional state of the shunted animals worsened, as indicated by body weight and biochemical variables. Since in the PCA rabbits, the total amino acid pools of muscle and plasma were seen to be increased and decreased, respectively, the results concerning the individual amino acids are given in terms of both the absolute and percentage values, the latter more often revealing high levels of statistical significance. PCA induced a marked rise in the intra- and extracellular concentrations of glutamine, while the values of glutamate and alanine showed a decline in muscle and plasma. The extracellular levels of methionine, phenylalanine, and tyrosine were raised, while those of the BCAA were diminished.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1987

[Intracellular amino acid concentrations in the musculature of 3 species of animals under physiologic, pathophysiologic and infusion therapy conditions].

In the first part of this paper methodological aspects of intracellular amino-acid analysis in three species of animals, i.e. in rats, rabbits, and cats are dealt with. The genetic homogeneity as well as the age of the animal groups, metabolic differences between carnivores and herbivores, the length of the intestine and, thus, the time elapsing before the postabsorptive state is reached, furthermore, the body size which, in studies with muscle biopsies, makes correlated samples either possible or impossible; all these factors are experimental variables potentially affecting the evidence of the results obtained. Amino acids being involved in ammonia detoxification or showing raised plasma levels in hepatic failure form the subject of the subsequent parts of this paper. In the muscle cells of the three above species investigated after an overnight fast, the concentration of glutamine was about 5.5 times and that of glutamate about 4.1 times higher than in human muscle. Regarding glutamine and glutamate, there were no marked differences between the three species. As to the other amino acids measured in the rats, rabbits, and cats, alanine, the branched-chain amino acid (BCAA) as well as methionine and phenylalanine had intracellular values similar to those observed in humans. To test the hypothesis that ammonia lowers the BCAA plasma levels by considerably increasing glutamine synthesis and decreasing the intracellular glutamate pool with consecutively intensified transamination of BCAA for partial replenishment of this pool, we infused ammonium salts and created portocaval shunts in animal experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1987

[Emergency call and medical missions. A six-months' prospective clinical system analysis of the Mannheim area].

The prehospital care of emergency patients has proved to be highly efficient for traumatic and coronary care cases. The critical factor for the rescue mission is the quality of the alarming information. In a prospective 6-month study with two mobile rescue units, all rescue missions were documented in a computerized form. Times for arrival and activities, times for return, type of alarming information, type of emergency, difference between primary and final diagnosis, cases of under- and overestimation of the primary diagnosis, and outcome of external cardiopulmonary resuscitations were listed. A guiding list including medical emergency symptoms and general emergency situations for assistance in deciding to alarm the rescue unit proved to be valid. Of a total of 2151 missions, 88.7% were primary rescue missions, 10.3% failed operations, and 1% secondary missions. The timetable and frequency of operations are shown in Figs. 1 and 2. In 34% of cases simultaneous emergency calls for two different places were received. The spectrum of 1908 missions included 34.8% internal medicine, 24.7% surgery, 14% intoxication, 12% neurological/psychiatric disease, 7.5% cardiopulmonary resuscitation, 4.6% others, and 2.7% primary death (Fig. 3). In 77.6% the primary diagnosis was confirmed by the clinician. Intoxication and epilepsy were overestimated at primary diagnosis, whereas myocardial infarction were underestimated in view of further clinical development. Only in 37.6% of patients reported to be unconscious could the unconsciousness be confirmed. Of 110 patients with prehospital cardiac arrest, 38% could be resuscitated with success; 5.5% of the total could leave the hospital (Fig. 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Emergency Medical Services↗
PubMed1986

[Amino acid uptake and release by colorectal cancer in man].

Little information is available regarding the amino acid exchange by human tumors. To characterize this exchange in vivo, 21 patients with resectable colorectal carcinomas were studied during curative operations. Concerning the amino acid uptake and release by peripheral tissues, 20 non-cancer patients served as controls. Both groups of subjects were well-nourished, as indicated by anthropometric and biochemical variables. In the cancer patients, we cannulated a peripheral artery and vein as well as a central tumor-draining vein and the portal vein. Plasma concentrations and concentration differences were determined in mumol/l and in percentages of the total amino acid amounts. Peripheral glutamate uptake per liter plasma was reduced in the cancer patients (p = 0.02). In these patients, the central tumor-draining vein contained less glutamine (p = 0.002) and more glutamate (p = 0.002) than the peripheral vein. Glutamine uptake by the tumor occurred more often than glutamine release, while glutamate had a negative balance across the tumor in all but three cases. The qualitative differences between the peripheral tissues and the tumors with respect to glutamine and glutamate exchange reached high levels of significance (p = 0.002 for both of the amino acids). In addition, the tumors released more glycine, ornithine, and tyrosine than the periphery. As to glutamine and glutamate metabolism, there was a significant difference between the tumors and the portal-drained organs (p greater than or equal to 0.05). The discussion of the results emphasizes the contributions made by the periphery and the tumor to the plasma amino pattern. The role of glutamine as a potential high importance energy source for neoplastic tissues is delineated.

Aged↗
PubMed1979

[Investigation on the postoperative behavior of plasma amino acids in metabolically healthy patients. 1st communication (author's transl)].

In 12 patients before and after vaginal hysterectomy the plasma amino acid levels were determined. Without parenteral feeding the changes in plasma amino acid patterns can be explained by effects of operation and anaesthesia alone. The branched-chain amino acids decreased after operation. The following rise was never exceeding the control level. Even without substitution the concentrations of phenylalanine, methionine, and glutamic acid were increased. Tyrosine concentration remained within normal levels while cystine fell significantly.

Adult↗
PubMed1979

[Utilization of maltose during shorttime parenteral nutrition (author's transl)].

Twelve metabolically healthy patients, who had to undergo cholecystectomy or gastric resection, were fed intermittently by the parenteral route (via veins of the upper limbs) post-operatively up to and including the 2nd post-operative day with a combined maltose-glucose solution in parallel with an 8% mixture of crystalline L-aminoacids. At an administration rate of 150 g maltose/day and 250 g glucose/day with the simultaneous administration of 80 g aminoacids, the mean carbohydrate utilisation was 82,5%. The glucose and maltose levels in the blood fluctuated in accordance with the infusion periods and the free fatty acids levels measured were their mirror image. On the whole free fatty acids were lowered significantly, which indicates adequate carbohydrate supply with consequent inhibition of lipolysis. The degree of tolerance was determined objectively by measurement of the acid-base parameter, gamma-GT, alkaline phosphatase, GOT, bilirubin, uric acid, creatinine and serum electrolytes. No changes were found which could be attributed to the administration of the infusion solution.

Adult↗