PubMed Health⌕ Search

Biomedical subjects

L Pérez Alvarez

Publications and source records attributed to L Pérez Alvarez.

15 recordsLinked to original sources
PubMed1998

[Expression of different HIV-1 phenotypic subpopulations through the natural history of the infection].

BACKGROUND: Multiple viral subpopulations coexist in an HIV infected patient with dynamics of selection established between them. In order to get insight on the phenotype of these subpoblations, and its relation with disease progression, we have studied the biological variability of HIV-1 in 113 patients. Variability was related with CD4+ T lymphocyte counts, clinical status, way of viral transmission and antiretroviral treatment. PATIENTS AND METHODS: 113 patients (80 adults and 33 children) were studied for HIV-1 isolation in cocultures of infected and non infected lymphocytes. Viral replication was evaluated as rapid (R)/slow (S) or high (H)/low (L). Syncytia formation was estimated in MT2 cell line (SI/NSI). The tropism toward lymphocytes and monocytes (LM) was studied on H9 and U937 cell lines. RESULTS: Up to 86.7% of viral isolates were R, 56.6% were H and 49.6% were SI. These percentages increased with disease progression. Eight viral strains were R/H/NSI cocultivated in MT2 cells and SI in cocultured lymphocytes (NSI/SI), which may be considered as a new phenotype. All the SI isolates and all the R/H (SI and NSI) isolates were LM. Three categories were established: R/H/SI/LM, R/H/NSI/LM and S/L/NSI/NLM. The first two categories corresponded to patients with CD4+ T lymphocytes <200 x 10(6)/I (56%, 50%). The third category corresponded to patients with > 500 x 10(6)/I (53.3%). CONCLUSIONS: Viral replication and SI phenotype, independently, are useful markers for severity of HIV infection. The biological differences among NSI of the 3 viral phenotype categories, including the new subgroup NSI/SI, may indicate the existence of more pathogenic NSI subpopulations.

Adolescent↗
PubMed1992

[Evaluation of the western blot test in the follow up of children born to HIV seropositive mothers].

We have made a follow-up study of 65 children born to HIV seropositive mothers. These children were studied during the first quarter of life and subsequently every three months thereafter to measure the usefulness of the Western Blot technique in the detection of the gradual development of seroreversion, as well as in HIV infection. The study of 25 mother-child pairs allowed us to anticipate seroreversion up to three months, showing an earlier and quicker finding than by indirect immunofluorescence. In the HIV diagnosis during the first 15 months of life, the sequential study of serum by Western Blot is able to detect the reappearance of new bands, indicating the endogenous production of antibodies in the child. The circunstance is observed in 7 out of 10 infected children, showing the reappearance of bands corresponding to antibodies against p-31 and/or p-55 proteins between the second and fourth quarter of life.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[HIV infection in infants under 15 months of age. Value of the p-24 antigen as a prognostic marker].

We have studied 65 children, born to HIV seropositive mothers, during the first quarter of life and afterwards every three-months. During this time, ten of the children (13%) became infected with the virus. The study of p24 antigen during the first 15 months of life showed an inverse relationship between the permanent presence of P24 antigen in the serum and the absence of anti-p24 antibodies. Since both markers were related to a bad prognosis, it is useful to carry-out the routine study of p24 antigen and its level in serum. Of the infections detected, 3 cases were early onset and the other 7 cases later onset. The three children from the first group died between 4 and 8 months of life, while the second group had a much more stable clinical situation. The children with early onset infections had T4 lymphocytes lower than 500 cell/mm3, detectable p24 antigen, and a fatal progression of the disease.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Early diagnosis of HIV infection in children born to seropositive mothers].

We have studied 70 children, born to HIV seropositive mothers, since the first trimester of life and every three months thereafter. The virological markers we used in the diagnosis included: 1) p24 antigen detection. 2) Autochthonous production of antibodies detected by Western Blot technique. 3) HIV isolation. 4) Specific determination of IgM antibodies. In infected children under 15 months of age, p24 antigen was positive in 78%, HIV was isolated in 75% and autochthonous production of antibodies occurred in 50%. IgM specific antibodies were detected in 92%, but these were also detected in the 33% of the children who seroreverted. In seroreverted children, the other three virological markers were negative. The problems due to the low sensitivity in p24 antigen detection, HIV isolation and the detection of autochthonous production of antibodies, as well as the low specificity of the IgM detection, means that it is necessary to simultaneously use several techniques in the diagnosis of these children.

Blotting, Western↗
PubMed1991

[Apical hypertrophic cardiomyopathy and coronary arteriovenous fistula].

We present a case of association of apical hypertrophic cardiomyopathy of the Japanese type and coronary arteriovenous fistula in a 56-year-old male who presented with anginal symptoms. Both cardiopathies can produce myocardial ischemia and angina, and their association could aggravate the ischemia. In our patient the symptoms were adequately controlled with Verapamil. The coexistence of these two rare entities in the same patient has recently been described in 2 other cases, allowing us to speculate on a possible etiological relation between the 2 abnormalities, probably both been originated in a common developmental error.

Aged↗
PubMed1990

[Images of magnetic resonance and computerized axial tomography in a case of subacute post-myocardial infarct heart rupture].

In a patient with clinical and hemodynamic criteria of cardiac tamponade, during the acute phase of myocardial infarction, a two dimensional echocardiographic study showed pericardial effusion with an echo-dense mass in the pericardial space. Subacute ventricular free-wall rupture diagnosis was suspected. A cardiac computerized tomography (CT) and magnetic resonance (MR) study was made. CT showed an elevated density (32 HU) of pericardial effusion suggesting hemopericardium. RM imaging showed a very high and homogeneous signal in the pericardial space consistent with a methemoglobin phase clot. Anatomic confirmation was not possible.

Acute Disease↗
PubMed1989

[Etiopathogenesis of HIV infection].

The knowledge of life's cycle of the acquired immune deficiency syndrome's virus (HIV) its complex genetic structure involving the interaction of positive and negative regulatory gene controlling the growth of the virus, its great genetic variability, the different pathogenic mechanisms, the cell-virus interaction, the different host-cells and the interaction of other pathogens, are all fundamentals facts for a better understanding of the various stages of infection by HIV until ultimate establishment of the Acquired Immune Deficiency Syndrome and also to explain the therapeutic difficulties until now.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Unusual viruslike particles in chronic non-A, non-B hepatitis in childhood.

Liver biopsies from 16 children with clinical and pathologic evidence of chronic hepatitis have been examined by electron microscopy for cytoplasmic and nuclear changes. Parallel studies by radioimmunoassay on sera from the same patients support the diagnosis of all these cases as non-A, non-B hepatitis (NANB). Ultrathin sections of the liver biopsies demonstrated in one case intranuclear hepatitis B virus-like core particles, 25 nm diameter. In a second biopsy from the same patient, the corelike particles could still be observed. This finding could be used either to support the thesis that a NANB virus is a member of the hepadnavirus group or to reflect the existence of seronegative cases of chronic HBV infection. Furthermore, we have observed in some mononuclear cells from the inflammatory infiltrate of a portal tract, some structures that resemble virus budding. There is a striking similarity between the morphology of these particles (which are enveloped and possess projections) and the ultrastructure of retrovirus.

Antigens, Viral↗