Biomedical subjects
Publications and source records attributed to A Arias.
Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and other enzymes related to carbohydrate metabolism were studied in rhizobia. A nicotinamide adenine dinucleotide phosphate-6-phosphogluconate dehydrogenase was detected in strains of the fast-growing group of Rhizobium but not in strains of the slow-growing group. An enzymatic differentiation of rhizobia was established.
The utilization of d-mannitol, d-arabitol, and d-sorbitol by Rhizobium meliloti was studied in extracts from mannitol-grown cells. Two different polyol dehydrogenases were induced by any of these polyols: (i) a nicotinamide adenine dinucleotide (NAD)-arabitol dehydrogenase and (ii) a NAD-sorbitol dehydrogenase, whereas polyol phosphate dehydrogenases were absent. d-Arabitol dehydrogenase was observed to act on both d-arabitol and d-mannitol, but d-sorbitol dehydrogenase acted specifically on d-sorbitol. d-Arabitol was oxidized to d-xylulose, d-mannitol and d-sorbitol were oxidized to d-fructose. An adenosine triphosphate-linked hexokinase which acts on d-fructose and absence of hexose isomerase were also detected in this organism.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The in vitro susceptibility to amphotericin B, fluconazole, itraconazole and ketoconazole of 545 Candida strains from patients treated at the University Hospital of the Canaries was determined by means of a microdilution test. The distribution of the species was as follows: Candida albicans (342), Candida tropicalis (70), Candida glabrata (68), Candida parapsilosis (65). Of Candida albicans isolates, 8.5% and 7.6% showed resistance to itraconazole and fluconazole respectively. Of C. tropicalis isolates 34.3%, 27.1% and 2.9% were resistant to itraconazole, fluconazole and ketaconazole respectively. For C. glabrata, 10.3% and 4.4% of the isolates under study demonstrated resistance to fluconazole and itraconazole respectively. Only 4.6% and 1.5% of C. parapsilosis isolates demonstrated resistance to fluconazole and itraconazole respectively. C. tropicalis was the most resistant strain and C. parapsilosis the most sensitive. The greatest percentages of resistance in vitro were seen with the triazoles.
The in vitro susceptibility of 84 isolates of Candida glabrata from patients treated at the University Hospital of the Canary islands to eight antifungal agents (amphotericin B, itraconazole, fluconazole, miconazole, clotrimazole, tioconazole and econazole) has been studied using the broth dilution micro-method. Among the eight antifungal agents tested, the smaller geometric mean corresponded to tioconazole, econazole, clotrimazole and miconazole. In contrast with fluconazole, a greater geometric mean has been achieved. All the C. glabrata isolates tested were sensitive to concentrations of 3.125 micrograms/ml of clotrimazole and miconazole, 6.25 micrograms/ml of amphotericin and ketoconazole. Concentrations of 12.5 micrograms/ml were needed to obtain 100% inhibition of isolates for econazole and tioconazole and concentrations of 25 and 50 micrograms/ml, respectively for itraconazole and fluconazole. Among our C. glabrata isolates, 2.4% were found to be resistant to amphotericin B. For fluconazole and itraconazole, 19.1% and 7.9% of isolates, respectively, were resistant. With reference to imidazoles, we obtained 2.4% and 3.6% resistance for tioconazole and econazole, respectively. No isolates were found to be resistant to ketoconazole, miconazole and clotrimazole. The results have shown a high activity of amphotericin B and itraconazole, observing a similar response with the five imidazole antifungals tested. The highest rate of resistance was found when fluconazole was used.
Intraventricular neurocytoma is a rare clinicopathological entity that has been recently described. We are reporting our experience with four diagnosed cases and the previously reported cases from the available literature are reviewed. These neoplasms occur mainly in young adults, and their histological diagnosis is difficult on light microscope, because they are almost indistinguishable from oligodendrogliomas. Nevertheless, the presence of tumoral cells arranged around nucleus-free fibrillary zones, resembling the large rosettes of pineocytomas and the immunohistochemical demonstration of synaptophysin are useful data for the pathological diagnosis. This diagnosis is easy on electron microscope, because it demonstrates the neuronal nature of tumoral cells. Regarding prognosis, we have found increasing evidence that these tumors are associated with a favourable course after surgery, and at present there is no clear evidence of the usefulness of radiotherapy.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.