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Biomedical subjects

C Fischer

Publications and source records attributed to C Fischer.

At least 325 records · Page 18Linked to original sources
PubMed1982

Combined treatment of preimplantation mouse embryos in vitro with sodium nitrite and x-rays.

Man takes up nitrite in a considerable amount. Effects of nitrite on DNA have been reported; therefore, interaction between nitrite and radiation might be possible. Preimplantation mouse embryos in vitro were treated with a combination of sodium nitrite (1 mM or 2.5 mM) and X-rays (0.94 Gy) in order to obtain some information whether radiation risk is influenced by the presence of nitrite. The microscopic visible development up to 144 h post conceptionem (h p.c.), the number of cell nuclei, and the number of micronuclei were determined. None of the experimental results gives any indication that radiation risk is influenced by nitrite. All effects after combined treatment correspond to the sum of the single effects.

Animals↗
PubMed1982

[Aspects of early somatosensory and auditory evoked potentials in neurologic comas and brain death].

Following stimulation of the median nerve at the wrist, SEPs, BAEPs and EEG activity were recorded during the same session in 20 comatose patients (13 head injuries, 6 comas of vascular origin, 1 anoxic coma). Patients were classified according to clinical data. In traumatic comas with clinically preserved brain stem reflexes (5 patients), BAEPs were all present, with preserved cervical N14 and scalp recorded P15 SEPs; the parietal N20 SEP was either present on both sides or unilaterally absent in case of hemispheric, possibly EEG silent, traumatic lesion. In comas with a reactive EEG and absent brain stem reflexes (8 patients), N14 and P15 SEPs were present when the parietal N20 component was absent on both sides. In these patients various aspects of BAEPs were observed, but in most cases (7 out of 8) either the BAEPs were completely absent or only peaks I or I and II were present. In brain-dead patients (7 cases) the cervical N14 was recorded in all cases, the P15 SEP was inconstant and the parietal N20 component was constantly abolished on both sides; in most cases (5 out of 7) all the BAEPs were absent. The practical use of evoked responses for the survey of comatose patients is discussed.

Adolescent↗
PubMed1982

Urinary and systemic metabolites of prostacyclin in the perfused rabbit kidney.

Rabbit kidneys were isolated and perfused with a solution to which tritiated or unlabeled prostacyclin was added continuously. The ureteral and venous effluents were collected separately and chromatographed. The peaks obtained by high-pressure liquid chromatography were analyzed using gas chromatography-mass spectrometry. The characteristic fragments of dinor-6-keto-PGF1 alpha could be detected from ureteral and venous effluents and represented material corresponding to 9.6 and 9.1% of the radioactivity recovered from chromatography, respectively. In addition, 39.2% (ureteral effluent) and 58.2% (renal venous effluent) of the radioactivity could be identified as 6-keto-PGF1 alpha, the stable in vitro hydrolysis product of prostacyclin. These results show that the kidney is able to degrade prostacyclin by beta-oxidation and that dinor-6-keto-PGF1 alpha formed in the kidney can be detected in both the vascular and urinary compartments.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

Prostacyclin metabolites in human plasma.

The major metabolites of prostacyclin (PGI2) in human plasma have been determined after intravenous infusion of tritium-labeled prostacyclin. Plasma was extracted and chromatographed. On high-pressure liquid chromatography (HPLC), several radioactive peaks could be resolved. The major peak containing 41.6% of the radioactivity had the retention volume of authentic 6-keto-prostaglandin F 1 alpha (6-keto-PGF 1 alpha), the stable in vitro hydrolysis product of prostacyclin. When the material of this peak was derivatized to the methoxime methyl ester trimethylsilyl ether and analyzed by gas chromatography-mass spectrometry, the fragments m/z 508 and 598, which are characteristic of this derivative of 6-keto-PFG 1 alpha were detected. A much smaller peak representing 6.6% of the radioactivity eluted from HPLC with the same retention volume as dinor-6, 15-diketo-13, 14-dihydro-PGF 1 alpha. On gas chromatography-mass spectrometry this material resulted in the fragments m/z 527, 468, 437, and 347, which are characteristic for this prostanoid. Finally, 10.1% of the radioactivity with ions m/z 571m 481, 391, and 354 on mass spectrometric analysis could be identified as dinor-6, 15-diketo-13, 14-dihydro-20-carboxyl-PGF 1 alpha. It is concluded that 6-keto-PFG 1 alpha represents the major breakdown product of prostacyclin in human plasma. In addition, dinor-6, 15-diketo-13, 14-dihydro-PGF 1 alpha and its w-oxidized analog could be identified circulating metabolites.

Chromatography, High Pressure Liquid↗
PubMed1981

Treatment of Huntington disease with gamma-acetylenic GABA an irreversible inhibitor of GABA-transaminase: increased CSF GABA and homocarnosine without clinical amelioration.

gamma-Acetylenic GABA (GAG, RMI 71.645), a potent irreversible inhibitor of gamma-aminobutyric acid transaminase, was given orally in various dosage schedules to 14 patients with Huntington disease. The biochemical effects of the drug on cerebrospinal fluid (CSF) concentrations of gamma-aminobutyric acid (GABA) and the GABA-containing dipeptide, homocarnosine, were measured in 10 of 14 patients. Treatment with GAG increased CSF concentrations of GABA and homocarnosine as compared to pretreatment values, suggesting that the drug increased brain GABA concentration. Despite this neurochemical effect, the clinical state was not improved. Except for single seizure episodes in five patients, GAG therapy was well tolerated. These results do not exclude the possibility that agents that augment CNS GABAergic function may prove useful in therapy of Huntington disease.

4-Aminobutyrate Transaminase↗
PubMed1981

[Diagnostic value of brainstem auditory evoked potentials (author's transl)].

The present work is an evaluation of brainstem auditory evoked potentials (BAEP) as a tool for neurological diagnosis. Filtered alternate clicks with monaural stimulation and ipsilateral recording between the vertex and the ipsilateral mastoid have been used. Normative data of the laboratory established in 50 normal subjects, mean age 35 years, and criteria for interpretation are given. 155 patients had or were suspected of having multiple sclerosis. In definite multiple sclerosis (33 patients), BAEP were abnormal in 67 p. 100 of the cases, among them the 4 patients with an internuclear ophtalmoplegia. In probable multiple sclerosis (54 patients) BAEP were abnormal in 41 p. 100 of the cases and in possible multiple sclerosis (68 patients) there were 19 p. 100 with abnormalities. Results show that BAEP are clearly a useful tool for diagnosis in progressive paraplegia, in optic neuritis, and in cases in which symptoms and signs lead to discuss posterior fossa tumours. In 66 patients with suspected or proved tumours (acoustic neurinomas excluded) and in 25 patients with vascular disease, the contribution of BAEP to neurological diagnosis is of unequal interest. In some cases BAEP only confirmed the data of the clinical examination. When tumours were diagnosed with the CT scan, BAEP could help in pointing out the accurate relation of the tumour with the brainstem and the auditory pathways. In 36 patients the contribution of BAEP was important in establishing the rostral extension of bulbocervical tumours or, mainly, in indicating the presence or absence of infiltrating brainstem tumours which were not clearly apparent on the CT scan.

Adult↗
PubMed1980

Therapeutic efficacy of sulfasalazine and its metabolites in patients with ulcerative colitis and Crohn's disease.

We studied the therapeutic efficacy of sulfasalazine and its metabolites sulfapyridine and 5-aminosalicylic acid in nine patients with Crohn's disease and in 23 patients with ulcerative colitis. In a randomized, controlled trial, we treated 11 patients for six weeks with 1 g of sulfasalazine three times a day, seven patients with 0.5 g of sulfapyridine three times a day, and 14 patients with 0.5 g of 5-aminosalicylic acid suppositories three times a day. The clinical state of the disease was characterized by an activity index, quality of stool, and remission rate. In addition, we monitored plasma levels of sulfapyridine, 5-aminosalicylic acid, and their acetylated metabolites. The initial activity index (mean +/- S.D.) was significantly reduced by sulfasalazine (from 245 +/- 129 to 100 +/- 71; P < 0.001) and by 5-aminosalicylic acid (from 251 +/- 65 to 90 +/- 93; P < 0.0001), but sulfapyridine was without benefit. Stool quality was also improved by sulfasalazine (82 per cent of the cases) and by 5-aminosalicylic acid (79 per cent). The highest remission rate was achieved with 5-aminosalicylic acid (86 per cent), followed by sulfasalazine (64 per cent) and sulfapyridine (14 per cent). Our investigations show that 5-aminosalicylic acid is the active moiety of sulfasalazine and that this effective metabolite may be an alternative to sulfasalazine in inflammatory bowel disease.

Adult↗
PubMed1980

Metabolism of prostacyclin and 6-keto-prostaglandin F1 alpha in man.

Labeled and unlabeled prostacyclin and 6-keto-PGF1 alpha were infused into healthy volunteers; urine was chromatographed on different systems including high pressure liquid chromatography. The peaks obtained by the latter method were derivatized to the methoxime methyl ester trimethyl silyl ether and analyzed by gas-liquid chromatography-mass spectrometry. After infusion of prostacyclin the following metabolites could be identified: dinor-4-keto-7,9,13-trihydroxy-prosta-11,12-enoic acid (20.5%), dinor-4,13-diketo-7,9-dihydroxy-prostanoic acid (6.8%), dinor-4,13-diketo-7,9-dihydroxy-prostan-1,18-dioic acid (19.7%), and 6-keto-PGF1 alpha (14.2%), the in vitro hydrolysis product of prostacylin. 6-Keto-PGF1 alpha infusion resulted in the same metabolites with the relative amounts of 22.4, 5.4, 7.0, and 6.8%, respectively. Additionally, 6,15-diketo,13,14-dihydro-PGF1 alpha (5.7%) could be identified. These data show that the metabolic pathway of prostacyclin involves hydrolysis to 6-keto-prostaglandin F1 alpha, subsequent beta-oxidation, dehydrogenation at C-15, reduction of the double bond between C-13 and C14, and omega-oxidation to the dicarboxyl metabolite. We conclude that dinor-4-keto-7,9,13-trihydroxy-prosta-11,12-enoic acid and dinor-4,13-diketo-7,9-dihydroxy-prostan-1,18-dioic acid represent the major urinary metabolites of prostacyclin in man. 6-keto-PGF1 alpha is a minor urinary excretory product following the administration of prostacyclin or 6-keto-PGF1 alpha.

6-Ketoprostaglandin F1 alpha↗
PubMed1980

Identification of the major metabolite of prostacyclin and 6-ketoprostaglandin F1 alpha in man.

Human volunteers were infused with 3H- and 2H-labeled prostacyclin or 3H-labeled 6-ketoprostaglandin F1 alpha and, in separate experiments, with the unlabeled prostanoids. The urine was purified by different chromatographic steps and finally separated into several fractions by high-performance liquid chromatography. The major fractions contained 20.5 and 23.0% of the eluted readioactivity for the metabolites of prostacyclin and 6-ketoprostaglandin F1 alpha, respectively. The structure of both metabolites was identified by gas-liquid chromatography-mass spectrometry as dinor-6-ketoprostaglandin F1 alpha. It is concluded that the major metabolite of prostacyclin and 6-ketoprostaglandin F1 alpha in man is dinor-6-ketoprostaglandin F1 alpha.

6-Ketoprostaglandin F1 alpha↗
PubMed1980

[Influence of below-freezing temperatures on the rate of post-mortem metabolism and the water-holding capacity in prerigor frozen beef muscles (author's transl)].

Prerigor beef is very suitable for the production of "bruehwurst" (frankfurter and bologna type sausages) because of its high waterholding capacity (WHC). This high WHC can be preserved for several months by rapid freezing of prerigor beef either unsalted or salted. In order to elucidate the optimum conditions of frozen storage for the preservation of high WHC, intact beef muscle, ground beef and ground, salted (2% NaC1) beef (neck muscles) were frozen at - 18 degrees or --40 degrees C in a thin layer (0.5-1 cm) 30--60 min after slaugther and stored at various temperatures between --5 degrees and --40 degrees C. The changes of biochemical parameters (content of glycogen and lactate, R-value [it corresponds to ATP concentration] and pH) in the tissue and the WHC of raw and heated muscle homogenates, prepared from the frozen material and containing 2% NaC1, were measured and related to time and temperature of frozen storage. At storage temperature of --18 degrees and --40 degrees C no appreciable biochemical changes occur in intact and ground, unsalted tissue over a period of 10 months. Above 18 degrees C, however, rising temperature causes an increased rate of ATP turnover and glycolysis. In ground muscle higher rates of postmortem metabolism are generally found than in the intact tissue. In prerigor salted and frozen beef a faster drug of ATP concentration (increase of R-value) occurs whereas the breakdown of glycogen to lactate is inhibited. The WHC of raw and heated muscle homogenates depends on time and temperature of frozen storage. As soon as the ATP concentration in unsalted beef falls to a level, at which the onset of rigor mortis occurs, the WHC of homogenates decreases markedly. With beef, ground and salted in the prerigor state and than frozen muscle homogenates are obtained which show always a high WHC even after complete breakdown at ATP during frozen storage. These results have practical consequences with regard to processing of hot-deboned beef.

Adenosine Triphosphate↗
PubMed1980

[Amnesic syndrome of posterior cerebral ischemia].

30 patients with acute onset of memory disturbances and visual impairment (cortical blindness or hemianopsia) are reported. For all of them, there was evidence of posterior cerebral artery ischemia. This clinical syndrome is compared with Dide and Botcazo's case report. The amnesia never recovered in 17 patients and was transient in 13 patients: in 4 of them it occurred during vertebral angiography and in 4 during general anaesthesia with anoxia. The main clinical features of the syndrome and the related bibliography are reviewed.

Adult↗