PubMed Health⌕ Search

Biomedical subjects

R Mateo

Publications and source records attributed to R Mateo.

61 records · Page 4Linked to original sources

Early detection of de novo hepatitis C infection in patients after liver transplantation by reverse transcriptase polymerase chain reaction.

BACKGROUND: Reverse transcriptase polymerase chain reaction (RT-PCR) can detect the viral genome and show hepatitis C recurrence in patients who undergo transplantation for chronic hepatitis C viral (HCV) infection. We investigated the utility of an RT-PCR-based HCV assay for early detection of viral RNA in de novo HCV infection after liver transplantation. METHODS: Pretransplantation antibodies and explanation HCV viral RNA status were obtained from 117 patients. Follow-up liver biopsy specimens were examined for evidence of hepatitis activity. Plasma samples during the period of time of the biopsy were assayed for HCV antibody and viral RNA. RNA was extracted from samples and reverse transcribed to cDNA. cDNA was amplified by PCR, and products were detected by liquid hybridization. RESULTS: Clinical hepatitis developed in seventeen of 117 patients who, before transplantation, were HCV antibody negative and explant viral RNA negative. Ten patients were plasma PCR negative and had known non-hepatitis C causes for the biopsy findings. Of the remaining seven patients, five (70%) were plasma RT-PCR positive before seroconversion in matched plasma samples. CONCLUSIONS: In liver transplant patients, the incidence of de novo clinical hepatitis is low, and HCV viral RNA in de novo clinical hepatitis C infection can be detected in the absence of HCV antibodies.

Base Sequence↗

Mycotoxins and mycotoxigenic moulds in nuts and sunflower seeds for human consumption.

A survey was carried out to obtain data on the occurrence of mycotoxins and the mycotoxin-producing potential of fungi isolated from nuts (almonds, peanuts, hazelnuts, pistachio nuts) and sunflower seeds in Spain. Thin-layer chromatography was used to separate the toxins. Aflatoxins were detected in one sample of almonds (95 ppb aflatoxin B1 and 15 ppb aflatoxin B2) and in one sample of peanuts at a level below 10 ppb of aflatoxin B1. 100% of samples showed variable incidence of fungal contamination. The predominant fungi present in samples were Penicillium spp, Aspergillus niger, A. flavus, A. glaucus and Rhizopus spp. The results showed that isolates of different species were able to produce aflatoxins B1, B2, G1, and G2, sterigmatocystin, ochratoxin A, patulin, citrinin, penicillic acid, zearalenone, and griseofulvin.

Analysis of Variance↗

Effect of the incubation conditions on the production of patulin by Penicillium griseofulvum isolated from wheat.

Sixty-four wheat samples from Spanish flour factories were screened for patulin and patulin-producing moulds. None of them was found to contain any patulin, whereas samples experimentally contaminated with this toxin proved it to be highly unstable. On the other hand, Penicillium griseofulvum was the only in vitro patulin-producing species found (19 samples). Mould growth in the samples was investigated by using yeast-sucrose medium (YES) and high-performance liquid chromatography (HPLC) to measure the amounts of toxin produced during 40 day's incubation at 20 and 28 degrees C. The highest yield rate of patulin was obtained between the 20th and 30th day of incubation; such a rate, however, was very low throughout the vigorous growth phase, during the first 20 days of incubation. The more appropriate temperature for incubation and patulin production was 28 degrees C. We also investigated the influence of other incubation conditions in the yield and found stationary dark cultures to be more efficient that shaken or fermentation cultures in YES medium. The best patulin yield achieved was 11.9 mg in the culture broth and 6.3 mg in the mycelium from 100 ml of medium.

Culture Media↗

Differentiation of Penicillium griseofulvum Dierckx isolates by enzyme assays and by patulin and griseofulvin analyses.

The production of patulin and griseofulvin by 49 different isolates of Penicillium griseofulvum Dierckx was analyzed by high-performance liquid chromatography. Eleven isolates were obtained from pistachio nuts, 37 were obtained from wheat seeds, and 1 was obtained from the American Type Culture Collection. Activities of 19 enzymes were also assayed by the API ZYM system. From these results it may be deduced that there are two different groups among the strains tested which cannot be distinguished by morphological and cultural characteristics. One group of isolates did not produce detectable amounts of patulin and griseofulvin when grown in sucrose-yeast extract and Wickerham media, while enzymatic activities were quantitatively distinct from the other group, which produced patulin and griseofulvin in variable proportions. Leucine arylamidase, phosphoamidase, and beta-D-glucosidase are the main enzymes with differing activities between the two groups. Differences in physiological characteristics among isolates of a single species reveal shortcomings in the classification of the penicillia based only on morphological criteria. Thus, determination of the ability to yield mycotoxins and antibiotics as well as determination of enzymatic activities appear to be very valuable tools in the taxonomy of these fungi and for food toxicology.

Chromatography, High Pressure Liquid↗

Capillary column gas chromatographic identification of sugars in honey as trimethylsilyl derivatives.

A method for identifying carbohydrates (mono-, di- and trisaccharides) in honey is presented. It is based on the separate preparation of both trimethylsilyl ethers and oxime trimethylsilyl ethers of the sugars followed by their gas chromatographic separation on a fused-silica capillary column coated with OV-101 using temperature programming. From the two chromatograms, the number of peaks given by each derivatized sugar, their relative retention times and peak-area ratios are used for identification. The identities of two unidentified trisaccharide peaks are considered. Quantitative applications to honey sugar analysis are discussed.

Carbohydrates↗

Live-donor liver transplantation: the USC experience.

BACKGROUND: Liver transplantation is currently the standard of care for patients with end stage liver disease. However due to the cadaveric organ shortage, live donor liver transplantation (LDLT), has been recently introduced as a potential solution. We analyzed and support our initial experience with this procedure at USC. MATERIAL AND METHODS: From September 1998 until July 2000, a total of 27 patients underwent LDLT at USC University Hospital and Los Angeles Children's Hospital. There were 12 children with the median age of 10 months (4-114) and 15 adults with the median age of 56 years (35-65). The most common indication for transplantation was biliary atresia for children and hepatitis C for adults. RESULTS: All donors did well postoperatively; the median postoperative stay was five days (5-7) for left lateral segmentectomy and seven days (4-12) for lobar donation. None of the donors required blood transfusion, re-operation or postoperative invasive procedure. However, five of them (18%) experienced minor complications. The survival rate in pediatric patients was 100% and only one graft was lost at nine months due to rejection. Two adult recipients died in the postoperative period, one from graft non-function and one from necrotizing fascitis. 37% of adult recipients experienced postoperative complications, mainly related to biliary reconstruction. Also 26% of the recipients underwent reoperation for some of these complications. CONCLUSION: LDLT is an excellent alternative to cadaveric transplantation with excellent results in the pediatric population. However, in adult patients it still carries a significant complication rate and it should be used with caution.

Adult↗

[Changes in carbohydrate metabolism in the HIV/AIDS patient].

Over the last few years, there has been a considerable reduction in the mortality and morbidity associated with HIV patients, due to the use of protease inhibitors which have led to a true revolution in the treatment of this infection. A new problem has arisen with the increased life expectancy: the onset of a plurimetabolic syndrome characterized by hypertriglyceridaemia, hypercholesterolaemia and hyperglycaemia; in addition to anomalies in composition and distribution of body fat (central obesity and loss of peripheral fat) due to the associated lipodystrophy. As a result of the metabolic alterations, there is an increase in the risk of cardiovascular disease. Hyperglycaemia is the result of insulin resistance and is detected in between 13.6% and 46% of patients, possibly leading to type 2 diabetes (diagnosed in between 2.4% and 7% of the patients). These alterations have been documented as potentially related with the use of protease inhibitors and other drugs used in the handling of HIV patients. The appropriate treatment of altered metabolism of carbohydrate requires: 1) a customized dietary approach depending on individual BMI and lipid alterations; 2) a physical exercise programme; 3) the use of insulin sensitization drugs: metformin and thiazolidinediones and, where the therapeutic goals are not achieved or there is a contraindication for oral hypoglycaemic drugs; 4) insulin therapy with regimens similar to other diabetic patients.

Acquired Immunodeficiency Syndrome↗