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T Ribeiro

Publications and source records attributed to T Ribeiro.

At least 19 recordsLinked to original sources
PubMed2003

Development, validation, and applications of a new laboratory-scale indirect impedancemeter for rapid microbial control.

We introduce a new laboratory-scale impedance-meter which is specially intended for indirect technique. It consists of a software system enabling data acquisition via a connected bus which is wired to the measuring cells. These measuring cells are individual impedance-meters that can be activated independently of one another. In the current configuration, the device is slightly affected by temperature, but it can register as little as 10.9 micromol of CO(2). With Bacillus subtilis, Escherichia coli, and Saccharomyces cerevisiae cultures, the conductance responses were highly replicable and repeatable for inocula concentrations of 1-10(8) colony-forming units (CFU) ml(-1). The main use for such devices could be the detection of contamination in foodstuffs. Several of these foodstuffs, when incubated at 37 degrees C, spontaneously release quite large amounts of CO(2). Our impedance meter, however, was able to detect an E. coli presence in canned French beans at 2.35 x 10(-2) CFU ml(-1) and a S. cerevisiae contamination of apple purée in glass jars at 6.1 x 10(-3) CFU ml(-1). The conductance response and the detection time (the time needed for a significant change in conductance) were correlated to the concentration of ampicillin (an antibiotic added to E. coli cultures). The device is thus able to detect the presence of inhibitory compounds in milk or other foodstuffs. Some industrial assays are in process to complement these laboratory tests. Compared with other available techniques for CO(2) measurement (manometry, infrared, radioactive labeling), the technique put forward here appears to be the best compromise between sensitivity, technical constraints, and cost. A commercial version of the impedance meter would enable routine measurements in the quality control of foodstuffs, pharmaceuticals, cosmetics and in R&D laboratories.

Bacillus subtilis↗
PubMed2001

A STR mutation in a heteropaternal twin case.

A heteropaternal male twin case with two men being alleged fathers was investigated as requested by the Court. Up to 37 PCR-based polymorphic DNA systems were studied in this case which was complicated by a paternal ACTBP2 mutation detected in one twin. This is the first report on a STR mutation in a double paternity case where both biological fathers were indisputably identified. The STR systems enable the resolution of these complex genetic relationships even in a case where a mutation in one STR locus was encountered.

DNA Fingerprinting↗
PubMed2000

Portuguese population and paternity investigation studies with a multiplex PCR--the AmpFlSTR Profiler Plus.

A Portuguese Caucasian population of 146 unrelated individuals was studied. DNA samples were amplified by multiplex PCR for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 using the AmpFlSTR Profiler Plus PCR Amplification Kit (Perkin-Elmer). All loci met Hardy-Weinberg expectations. Forensic statistical parameters were according to those obtained by other authors. Statistical differences were observed concerning three loci when comparing the Portuguese Caucasian population and an Italian Caucasian population, although these differences mainly concern the less frequent alleles. Eighty-three paternity investigation cases were analysed. Exclusions in between three and nine loci were observed in all the 23 exclusion cases obtained. Most of the non-exclusion cases had probability of paternity > 99.9%. Two cases with an isolated genetic incompatibility between the alleged father and the child were detected, which may indicate probable mutation cases. These results demonstrate that the AmpFlSTR Profiler Plus is a suitable multiplex for paternity investigation in the Portuguese population.

Alleles↗
PubMed2000

Sequence variation of new alleles at the short tandem repeat D19S253 locus.

This paper reports the sequences of two new alleles identified in a population database study on the short tandem repeat D19S253 locus. A Portuguese Caucasian population and a Portuguese African population were studied. Forty-four selected alleles were sequenced and 11 different alleles were found. All the sequenced alleles shown to possess a simple tetranucleotide GATA repeat region structure. The two new alleles, alleles 6 and 16, follow the simple repeat pattern. During paternity investigation casework, 1028 meiosis were analyzed and five isolated genetic incompatibilities detected. In one case, a non-detectable allele with the used set of primers could be the explanation. In the other four cases, single-step mutations could be considered. The mutation rate obtained for this locus was 3.89 x 10(-3).

Alleles↗
PubMed1999

The role of transjugular liver biopsy in a liver transplant center.

Transjugular liver biopsy is a particularly useful procedure in overcoming the classic limitations of percutaneous biopsy, such as hemorrhagic diathesis or tense ascites. The authors evaluated the impact that this technique had in their liver transplant program, considering performance and safety in 160 procedures. Histologic characterization was accomplished in 75% of cirrhotic patients and in 96% of patients with acute liver disease. Confirmation of a presumptive diagnosis was made in 76% of patients and a previously unsuspected diagnosis was raised in 11%. Hemochromatosis, Wilson's disease, and acute alcoholic hepatitis were the most challenging diagnoses and, together with patients with liver failure, had the most relevant implications in transplant decisions. The availability of transjugular liver biopsy provided decisive information regarding patient selection and the best timing to proceed with transplantation.

Adolescent↗
PubMed1998

[Hepatic schistosomiasis: diagnostic difficulties in a non endemic area].

Schistosomiasis is a major cause of liver damage and portal hypertension, especially in tropical countries, affecting about 200 million people in the world. We report the cases of two patients presenting persistent alterations of serum liver enzymes. We enhance the importance of considering the history of past travels and a liver biopsy to diagnose an infrequent parasite induced liver disease in a non endemic area such as Portugal. Some observations are made about the diagnosis and treatment of this parasitic disease.

Biopsy↗
PubMed1998

[The first assessment of hepatitis E virus seroprevalence in northern Portugal].

Hepatitis E is an enterically transmitted acute viral hepatitis, etiologically associated with a recently characterized virus, the hepatitis E virus (HEV). Outbreaks mainly occur in developing countries and as sporadic cases in endemic regions. The authors present the first serological assessment in northern Portugal to assess the presence of anti HEV IgG, using the Elisa test, the EIA and HEV Abbott, in samples from 50 blood donors and 103 chronic liver disease patients. In 2 blood donors (4%) and in 7 (6.8%) liver patients, the HEV antibody was detected with optic densities/cut off always below 2.5. Only one patient had a sojourn in an endemic region; the presence of anti-HEV was not significantly associated with other hepatotropic viruses. With this test the authors conclude that 4% of our blood donors are seropositive for anti-HEV antibody and that this percentage is not significantly higher in chronic liver disease patients (6.8%). They also think that a new generation of immunological assays, designed for serological diagnosis of HEV infection, will provide a further understanding of hepatitis E epidemiology.

Adult↗