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Biomedical subjects

N Fernandes

Publications and source records attributed to N Fernandes.

13 recordsLinked to original sources
PubMed2006

The seroprevalence of human infection with Rickettsia slovaca, in an area of northern Spain.

An epidemiological survey was undertaken to explore human exposure to Rickettsia slovaca in two provinces of northern Spain. When IFAT were used to test 200 members of the general population for antibodies to rickettsiae of the spotted-fever group, six (3.3%) were found positive, presumably, since Dermacentor is one of the most common genera of human-biting tick in the study area, for antibodies to R. slovaca. Thirty-one (16.9%) of an additional 183 subjects who presented shortly after being bitten by ticks were also found seropositive. The difference in seroprevalence between the general and the tick-bitten populations was significant. Subject gender had no influence on seroprevalence in either population, although, in the tick-bitten group, age and occupation did have a significant influence on the prevalence recorded. Immunoblotting was used to confirm the presence of antibodies in the five subjects, all from the tick-bitten group, found to have acute infections. Three D. marginatus ticks obtained from three of these acute cases were found PCR-positive for R. slovaca DNA.

Acute Disease↗
PubMed2001

Kruppel-like factor 4 regulates laminin alpha 3A expression in mammary epithelial cells.

Laminin-5, the major extracellular matrix protein produced by mammary epithelial cells, is composed of three chains (designated alpha3A, beta3, and gamma2), each encoded by a separate gene. Laminin-5 is markedly down-regulated in breast cancer cells. Little is known about the regulation of laminin gene transcription in normal breast cells, nor about the mechanism underlying the down-regulation seen in cancer. In the present study, we cloned the promoter of the gene for the human laminin alpha3A chain (LAMA3A) and investigated its regulation in functionally normal MCF10A breast epithelial cells and several breast cancer cell lines. Using site-directed mutagenesis of promoter-reporter constructs in transient transfection assays in MCF10A cells, we find that two binding sites for Kruppel-like factor 4 (KLF4/GKLF/EZF) are required for expression driven by the LAMA3A promoter. Electrophoretic mobility shift assays reveal absence of KLF4 binding activity in extracts from T47D, MDA-MB 231, ZR75-1, MDA-MB 436, and MCF7 breast cancer cells. Transient transfection of a plasmid expressing KLF4 activates transcription from the LAMA3A promoter in breast cancer cells. A reporter vector containing duplicate KLF4-binding sites in its promoter is expressed at high levels in MCF10A cells but at negligible levels in breast cancer cells. Thus, KLF4 is required for LAMA3A expression and absence of laminin alpha3A in breast cancer cells appears, at least in part, attributable to the lack of KLF4 activity.

Binding Sites↗
PubMed2000

Peroneal latency in normal and injured ankles at varying angles of perturbation.

The aim of this study was to determine whether there was a difference in latency of the peroneus longus muscle at varying amplitudes of ankle inversion perturbation and between individuals with and without a history of ankle injury. Thirty-four male athletes from different football codes (soccer, rugby) received four random tilts to their left ankles at 5 degrees, 10 degrees, and 15 degrees in the frontal plane on a dual platform trap door. Peroneal latency was defined as the time difference between onset of the trap door movement, as detected by an accelerometer, and the onset of muscle activation above a resting baseline, as recorded using surface electromyography. Latency was determined using an algorithm. A series of repeated measures analyses of variance indicated that the latency was reliable between trials. There was no statistical evidence that history of injury or subjective ankle instability influenced the latency; however, there was a systematic difference between dominant and nondominant legs (dominant, 6.3 ms faster), and there was a small systematic effect (3 ms) for the angle of inversion perturbation. Muscle latency responses in male football players are thought to be influenced more by dominance than by history of injury or amplitude of perturbation.

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

Reliability of the peroneal latency in normal ankles.

The aim of this study was to determine the reliability of peroneal latency between trials and to compare the right and left sides in healthy subjects. A dual platform trapdoor was constructed to tilt the right or the left ankle by 30 degrees in the frontal plane. Electromyography recorded the onset of peroneal activity in response to this perturbation, and an accelerometer detected the onset of trapdoor movement. Peroneal latency was determined algorithmically as the time difference between the onset of trapdoor movement and the onset of peroneal activity. Twenty trials were recorded from 31 right leg dominant, healthy subjects. Peroneal latency was measured successfully for 613 trials (99% success rate). A repeated measures analysis of variance showed a main effect for side with the right, dominant side recording a longer latency. Intertrial reliability of the peroneal latency was high (intraclass correlation coefficients for the right and left legs were .91 and .82, respectively). Thus, peroneal latency is a reliable measure of the polysynaptic reflex ares involved in the response of these muscles to a sudden inversion stress.

Adult↗
PubMed1996

Gastrointestinal actions of buprenorphine: are different receptors involved?

The effects of buprenorphine on castor-oil-induced diarrhoea, gastrointestinal transit and ethanol-induced gastric lesions in rats were compared to the same effects of morphine. Like morphine, buprenorphine prevented castor-oil-induced diarrhoea. However, it has no effect on gastrointestinal transit per se but prevented the inhibitory action of morphine. While morphine protected against ethanol-induced gastric lesions, buprenorphine aggravated them. It is suggested that different types/subtypes of opioid receptors may be involved in the gastrointestinal actions of buprenorphine.

Animals↗