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961.
Teresa Coccini Luciano Maestri Francesco S. Robustelli della Cuna L. Bin Lucio G. Costa Luigi Manzo 《Archives of toxicology》1996,70(11):736-741
Styrene is stereoselectively oxidized by cytochrome P450 to its reactive metabolite, styrene oxide. The (R)- and (S)-enantiomers
of styrene oxide can be conjugated with glutathione (GSH) to both (R)- and (S)-diastereoisomers of the specific mercapturic
acids, N-acetyl-S-(1-phenyl-2-hydroxyethyl)-L-cysteine (M1) and N-acetyl-S-(2-phenyl-2-hydroxyethyl)-L-cysteine (M2). Several investigations have indicated different toxic potential of the (R)- and (S)-configurations of styrene
oxide and its GSH- and N-acetyl-conjugates. In this study the mercapturic acid diastereoisomers were measured in the urine
of rats exposed to styrene in combination with ethanol, a good inducer of styrene metabolism. Male Sprague-Dawley rats were
given an isocaloric liquid diet containing ethanol (5% w/v) for 3 weeks. Starting from the 2nd week, the animals were also
exposed to styrene vapours (300 ppm, 6 h/day, 5 days/week) in a dynamic exposure chamber. Both the (R)- and (S)-diastereoisomers
of the M1 and M2 as well as the conventional biomarkers, mandelic acid (MA) and phenylglyoxylic acid (PGA) were measured in
urinary samples. Approximately 30 and 25% reduction of the levels of brain non-protein sulfhydryls (NPS) was observed in the
animals given styrene and ethanol, respectively, while the combined ethanol and styrene treatment resulted in a 60% decrease.
Ethanol consumption also resulted in higher urinary levels of the M1-R, M1-S and M2 metabolites associated with increased
M1-R/S ratio and higher urinary MA excretion compared to animals treated with styrene. These results suggest that the urinary
mercapturic acid diastereoisomers may be used as a noninvasive tool to examine stereoselective patterns of styrene metabolism
in vivo, as well as their alterations caused by ethanol. These compound-specific mercapturic acids may also be valuable indicators
of styrene-induced disorders of GSH homeostasis in nonaccessible organs.
Received: 19 December 1995/Accepted: 10 May 1996 相似文献
962.
Magnetic resonance imaging and pathologic findings in a 28-year-old patient with a giant deep benign fibrous histiocytoma
in the popliteal fossa of the right knee are described. The MR imaging findings include a well-delineated oval mass with low
signal intensity on T1-, and high signal intensity on T2-weighted, images, and marked peripheral contrast enhancement. To
the best of our knowledge, this is the first report on the MR findings in this entity.
Received 28 July 1997; Revision received 21 October 1997; Accepted 27 October 1997 相似文献
963.
Bharti Razdan Peter J. Marro Outi Tammela Rajiv Goel Om Prakash Mishra Maria Delivoria-Papadopoulos 《Brain research》1993,600(2):308-314
The effect of hypoxia on the structure and function of the synaptosomal membranes and myelin fraction (glial cells, neuronal cell bodies and axonal membranes) was investigated by measuring Na+,K+-ATPase activity and levels of lipid peroxidation products in cerebral cortical synaptosomal membranes and myelin fractions obtained from newborn piglets. Hypoxic hypoxia was induced and cerebral hypoxia was documented as a decrease in the ratio of phosphocreatine to inorganic phosphate (PCr/Oi) using31P-NMR spectroscopy. PCr/Pi decreased from baseline of2.93 ± 0.76to0.61 ± 0.36 during hypoxia. The synaptosomal membrane Na+,K+-ATPase activity decreased from a control value of56.6 ± 3.7to40.4 ± 6.0 μgmol Pi/mg protein/h during hypoxia. The level of conjugated dienes increased from zero (reference value) to4.5 ± 2.7 nmol/mg lipid and the level of fluorescent compounds increased from23.5 ± 2.2to92.6 ± 46.4 ng quinine sulfate/mg lipid in the synaptosomal membranes during hypoxia. No change in myelin fraction Na+,K+-ATPase activity or levels of lipid peroxidation products were noted. These data indicate that sunaptosomal membranes, rich in polyunsaturated fatty acids, are more susceptible to oxygen free radical mediated lipid peroxidative damage during hypoxia. 相似文献
964.
965.
Spontaneous remission in a patient with therapy-related myelodysplastic syndrome (t-MDS) with monosomy 7 总被引:1,自引:0,他引:1
B. Renneboog V. Hansen P. Heimann A. De Mulder F. Janssen & A. Ferster 《British journal of haematology》1996,92(3):696-698
We describe a case of spontaneously reversible refractory anaemia, a subtype of myelodysplastic syndrome (MDS), with monosomy 7 secondary to chronic treatment with azathioprine (AZA) in a young renal transplant recipient. AZA was stopped after that conventional cytogenetics and fluorescence in situ hybridization (FISH) had demonstrated the existence of a monosomy 7 clone. 4 months later, haematological values had considerably improved and the karyotypic examination as well as the FISH analysis were normal. The spontaneous remission of this MDS with monosomy 7, which is usually associated with a particularly poor prognosis, could be due to the recovery of a better immunosurveillance following the withdrawal of AZA. 相似文献
966.
967.
Objective: This international postmarketing observational study of flunarizine was designed to evaluate, in routine clinical practice,
the risk/benefit ratio of flunarizine in its approved indications, namely prophylaxis of migraine and treatment of vertigo.
Comparator drugs were propranolol in migraine and betahistine in vertigo. The study was carried out by 498 general practitioners
in Belgium, The Netherlands and Germany, whose participation had been requested by mail. In total 3186 patients were entered:
1601 in the two migraine cohorts and 1585 in the two vertigo cohorts.
Results:
In the migraine study, treatment results with propranolol tended to be somewhat better than those with flunarizine, but a
selection bias cannot be excluded. There was no clear difference regarding efficacy between flunarizine and betahistine in
the vertigo study. The safety evaluation focused on extrapyramidal symptoms (EPS) and depression. Overall, EPS were noted
in only four patients, two in the vertigo-betahistine and two in the migraine-flunarizine cohort. A total of 70 patients developed
depressive symptoms (34 in the flunarizine and 24 in the propranolol migraine cohorts, but only 7 in the flunarizine and 5
in the betahistine vertigo cohorts). Patients with migraine were clearly more prone to depression than patients with vertigo,
regardless of their treatment. Additional risk factors for depression were a history of depression, and, in the migraine flunarizine
cohort, a high number of previous migraine treatments.
Received: 23 October 1995/Accepted in revised form: 20 February 1996 相似文献
968.
Treatment of End-Stage Renal Disease in Central and Eastern Europe: Overview of Current Status and Future Needs 总被引:2,自引:0,他引:2
Bolesaw Rutkowski Aleksandru Ciocalteu Ljubica Djukanovic Istvan Kiss Aleksander Kovac Momir Polenakovic Zvonimir Puretic Rafail Rozental Maria Stanaityte Irina Tareyeva Vladimir Teplan Jeff Zavitz Krivoshiev Stefan & Kveder Rado 《Artificial organs》1998,22(3):187-191
The situation of end-stage renal disease (ESRD) patients in central and eastern Europe was very poor for many years during the so called socialistic era. Economical and political liberation resulted in the significant growth of renal replacement facilities in this region. The number of hemodialysis units increased significantly (56%) during the period 1990–1996, and the number of patients treated with this modality has risen by 75%. More dramatic progress was achieved in peritoneal dialysis. The number of units performing this method of renal replacement therapy (RTT) increased by 277% and the number of patients by more than 300%. Not only quantitative but also qualitative changes were observed. More modern hemodialysis machines installed in the vast majority of units allow for the performance of bicarbonate dialysis, controlled ultrafiltration, and sodium profile modeling. Also, a wider choice of biocompatible dialyzers has become available during the last few years. The number of centers performing renal transplantation has increased significantly, but the number of renal transplants has not followed this progress. Despite all the progress, further development of all RRT methods is necessary to achieve acceptance rates comparable to those observed in developed countries. 相似文献
969.
ABSTRACT: Nigeria generally has overlooked the health needs of its adolescents. To determine student perceptions of their health-related needs, some 600 students in Uyo, the capital of Akwa Ibom State, were surveyed, and they identified several concerns. Their responses provided the basis to offer five recommendations for action: improve the quality of school health service facilities and personnel available in the secondary schools; implement a comprehensive national program of drug education and control; provide a healthful school environment; assess the quality and quantity of food provided to students, especially in boarding schools; and implement a comprehensive school health education program in Nigerian schools. 相似文献
970.
Anna Pizzirusso Patrizia Oliva Sabatino Maione Michele D’Amico Francesco Rossi L. Berrino 《Naunyn-Schmiedeberg's archives of pharmacology》1998,357(5):514-518
In order to evaluate the role played by vasopressin on pressor responses elicited by stimulation of the periaqueductal gray
(PAG) area by excitatory amino acids we carried out in vivo studies in genetically vasopressin deficient rats (Brattleboro).
Microinjections of l-glutamic acid (glutamate, 0.6 to 60 nmol/rat) or N-methyl-d-aspartic acid (NMDA, 0.07 to 7 nmol/rat)
into the PAG area of freely moving Brattleboro rats induced increases of arterial blood pressure values significantly lower
than those obtained in Long Evans rats (control) (glutamate in Brattleboro rats: from +2±1 mmHg to 16±3 mmHg; glutamate in
Long Evans rats: from +16±2 mmHg to +36±4 mmHg; NMDA in Brattleboro rats: from +5±2 mmHg to +34 ±8 mmHg; NMDA in Long Evans
rats: from +18±7 mmHg to 80±9 mmHg; n=5). Similarly, in anaesthetized Brattleboro rats (urethane 1.2 g/kg i.p.) pressor responses to NMDA microinjections (0.7
nmol/rat) into the PAG area were significantly lower than in Long Evans rats (controls) (+15±3 mmHg vs +24±4 mmHg). In Long
Evans rats NMDA injection also reversed blood pressure decrease induced by ganglionic blocker, hexamethonium and/or losartan
(3 mg/kg i.v.), an AT1 receptor antagonist. In Brattleboro rats, NMDA injection did not reverse blood pressure decreases induced
by hexamethonium (5 mg/kg i.v.). Moreover, hexamethonium induced blood pressure decrease was not reversed by acetylcholine
injection (137 nmol/rat) into the PAG area of anaesthetized Long Evans rats, but if injected before hexamethonium, acetylcholine
was able to increase blood pressure (+25±3 mmHg). Our results document: i) the importance of the PAG area in the control
of cardiovascular system; ii) the involvement of excitatory amino acids in the neural control of vasopressin release; iii)
the close relationship between glutamate and vasopressin in the central blood pressure regulation.
Received: 1 April 1997 / Accepted: 2 February 1998 相似文献