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Biomedical subjects

R Grau

Publications and source records attributed to R Grau.

29 records · Page 2Linked to original sources
PubMed1993

Effects of bis(tri-n-butyltin)oxide in Japanese quail exposed during egg laying period: an interlaboratory comparison study.

The guideline no. 206 for testing of chemicals of the Organization for Economic Cooperation and Development (OECD) comprising an avian reproduction test using the Japanese quail (Coturnix coturnix japonica; Termminck and Schlegel 1849) as pair-hold test organisms has been applied in a version that reduced the treatment period to 6 weeks without any pretreatment. In the present study bis(tri-n-butyltin)oxide, C.A. No. 56-35-9 (tributyltin oxide, TBTO) was examined by five participants in an interlaboratory comparison test. A comparable regimen of dosing was performed by all participants starting either with 24 or 60 mg/kg TBTO in the feed and ending with 150 or 375 mg/kg. Within this dose range no signs of toxicity in adults were observed. Substance-related effects however were obvious with regard to egg production, fertility, hatching success, and survival of 14 day-old chicks. A clear dose dependency was given regarding effects on egg weight and on hatchability. The no-observed-effect concentrations for these two parameters was 60 mg/kg TBTO, characterizing these parameters as the most sensitive in this investigation. With the presented set of test parameters further aspects of subchronic toxicity in adults and chicks can be assessed as well as the validity of the performed test. Comparing the results for most test parameters consistency is obvious, thus confirming the applicability of the presented test guideline.

Animals↗
PubMed1993

Regulation of the synthesis of unsaturated fatty acids by growth temperature in Bacillus subtilis.

Bacillus subtilis synthesizes, almost exclusively, saturated fatty acids, when grown at 37 degrees C. When cultures were transferred from 37 degrees C to 20 degrees C, a chloramphenicol- and rifampicin-sensitive synthesis of a C-16 unsaturated fatty acid was observed. Synthesis of this compound reached a plateau after 5 h at 20 degrees C, reaching levels of 20% of the total fatty acid content. [14C]-labelled fatty acids attached as thioesters to acyl-carriers compounds, such as coenzyme A (CoA) or acyl-carrier protein (ACP) synthesized de novo by glycerol-requiring auxotrophs deprived of glycerol to arrest phospholipid synthesis, could not be desaturated at 20 degrees C. Desaturation of these fatty acids was readily observed when glycerol was restored to the cultures allowing resumption of transfer of acyl-moieties from acyl-thioesters to phospholipid. It was also observed that depletion of the pools of CoA and ACP by starvation of pantothenate auxotrophs had no effect on the observed synthesis of unsaturated fatty acid at 20 degrees C. The overall results indicate that synthesis of unsaturated fatty acids in B. subtilis is a cold-inducible process and that phospholipids are obligate intermediates in this fatty acid desaturation pathway.

Acetyl Coenzyme A↗
PubMed1993

Schizophrenia in epilepsy: seizure and psychosis variables.

Prior studies have incompletely established a relationship between epilepsy and schizophrenia, primarily because of methodological difficulties. We undertook a two-part retrospective investigation of neurology clinic patients with epilepsy and schizophrenia. Part I: Interictal schizophrenic disorders occurred in 149 (9.25%) of 1,611 epileptic outpatients, compared with only 23 (1.06%) of 2,167 migraine outpatients. Part II: Among age- and sex-matched groups, we compared 62 epilepsy-with-schizophrenia patients with 62 epilepsy patients on six seizure variables, and we compared them with 62 schizophrenia patients on 10 psychosis variables. The epilepsy-with-schizophrenia group had a later epilepsy age of onset with more complex partial seizures, more patients with auras, and fewer patients with generalized epilepsy. Except for increased suicidal behavior, epileptic patients did not differ from controls on psychosis variables; however, psychotic symptoms often emerged with increased seizure activity. Together these results support a distinct association of schizophrenic disorders with epilepsy, particularly with seizures emanating from the temporal limbic system.

Adult↗
PubMed1991

Isolation and characterization of Bacillus subtilis mutants blocked in the synthesis of pantothenic acid.

We have produced and characterized by physiological and enzymatic analyses pantothenate (pan) auxotrophs of Bacillus subtilis. panB auxotrophs are deficient in ketopantoate hydroxymethyltransferase, whereas panE mutants lack ketopantoic acid reductase. The pan mutations were mapped by phage PBS1-mediated two-factor crosses and found to be located in the interval purE-tre of the genetic map of B. subtilis.

Alcohol Oxidoreductases↗
PubMed1991

The postictal psychosis of epilepsy: investigation in two patients.

Patients with epilepsy have a higher incidence of psychosis. Epilepsy-related psychotic behaviors include a chronic interictal schizophreniform illness, an "alternating psychosis" which remits with seizure activity, and ictal or perictal psychotic behaviors. In addition, there is an uncommon and less understood psychosis characterized by brief psychotic episodes during the postictal period. This report describes two patients with postictal psychosis and correlates their behavior with the pattern of seizures, electroencephalographic discharges, and anticonvulsant and psychotropic medications. The findings suggest that postictal psychosis results from increased epileptiform activity and continued cerebral dysrhythmia, has a latency in onset and is not due to the immediate postictal delirium, and reflects an exacerbation of underlying psychopathological tendencies. This report further discusses the potential pathophysiological mechanisms and management of this disorder.

Adult↗
PubMed1984

[Not Available].

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Canada↗
PubMed1984

Increased hepatic microsomal T3 production in vitro induced by insulin administration in rats in vivo.

Rats were treated with insulin infusion over 12 h with or without addition of cycloheximide and compared with controls. T4 to T3 deiodination in microsomal liver fraction was measured. Insulin treatment led to an increase in T3 production, whereas this effect was blunted by the inhibition of protein synthesis by cycloheximide. Neither serum concentrations of T4 nor the liver content of non-protein-bound sulph-hydryl groups explained the alterations in T3 production. It is strongly suggested that insulin directly acts on T4-5'-monodeiodination by stimulating de novo synthesis of protein.

Animals↗
PubMed1984

T3-hyperthyroidism caused by enhanced and shifted T4-conversion.

Radioactivities of endogenously labelled thyroid hormones following in vivo application of 131 I and extraction from serial blood samples, show that T4 secretion is enhanced in T3-hyperthyroidism as it is in T4-T3-hyperthyroidism. In an extreme case of T3-hyperthyroidism with serum concentrations (SC) of T3 nearly equal to T4 (1000 ng/dl and 1800 ng/dl, respectively) tracer studies revealed a very short half life of T4 when compared to T3 (21.8 and 20.2 hrs., respectively). In 110 cases with both types of hyperthyroidism, regression analysis showed that T3/T4 ratio as an indicator of T4 conversion, as well as T3/rT3 ratio as an indicator of the direction of the conversion, are related to T4SC (r = -0.84 and -0.72, respectively, p less than 0.001). T3-hyperthyroidism is described by high values of these ratios. For the definition of T3-hyperthyroidism it is suggested that both T4 and rT3SC are within the normal range (T4 less than or equal to 11.5 micrograms/dl, rT3 less than or equal to 43.0 ng/dl) and according to this definition, T3/rT3 is higher than in T4-T3-hyperthyroidism and in an undefined group (24.8 +/- 4.5 vs. 6.3 +/- 0.4 or 7.5 +/- 0.4, respectively). By means of the ratios the undefined group may be allocated to T4-T3-hyperthyroidism. The T3/rT3 ratio is value of greater than 10 has a frequency of 88% in thus defined T3-hyperthyroidism and a ratio of less than or equal to 10 is found in 90% of the other cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Granulocytes↗