Biomedical subjects

L E Soto-Ramirez

Publications and source records attributed to L E Soto-Ramirez.

6 recordsLinked to original sources

PubMed1998

Nocardiasis in patients with HIV infection.

The frequency of Nocardia infection in HIV-infected patients has increased during the past few years from 0.3% in 1985 to 1.8% in 1989. Although it is not of great concern as an AIDS-associated infection, the nonspecific clinical presentation in these patients might be confused with other lung infections such as tuberculosis (TB). The mortality rate can be as high as 60%. The authors diagnosed three homosexual men with nocardiasis among 1060 HIV-infected patients (0.2%) in a tertiary care center in Mexico City from 1981 to 1997. The mean age was 32 years. The CD4 count was less than 260 cells/mm3 in all these individuals. The clinical presentations were subacute sinusitis, chronic localized abdominal abscess, and acute disseminated nocardiasis. The respective associated infections were none; TB and cytomegalovirus (CMV); and candidiasis, TB, CMV, Isospora belli, and disseminated Mycobacterium avium complex (MAC). Trimethoprim/sulfamethoxazole (TMP/SMX) was the treatment in all the cases; at the time of this writing, two patients were living and one had died during the acute episode. A literature search uncovered 130 cases of Nocardia infection in HIV patients since 1982. According to the published data and our results, nocardiasis should be suspected in those HIV-infected patients who (1) do not respond to appropriate antituberculous treatment; (2) are intravenous drug users; and (3) develop a characteristic pericardial infection. Finally, adequate surgical or percutaneous drainage of abscesses are extremely valuable for diagnosis and therapy.

AIDS-Related Opportunistic Infections↗

PubMed1998

Bridging the gap?

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AIDS Vaccines↗

PubMed1997

Genetic variation within human immunodeficiency viruses generates rapid changes in tropism, virulence, and transmission.

The human immunodeficiency viruses (HIV-1) undergo high rates of variation. Only a few point mutations in the envelope gene are required to switch the tropism of HIV-1 from a growth preference for monocytes to lymphocytes or to acquire lytic properties for rapid killing of infected T4 lymphocytes. Since heterosexual transmission efficiency is high for HIV-1's that are most prevalent in Africa or Asia, but low for HIV-1 B, which dominates in the US and western Europe, we asked whether African and Asian viruses had a particular tropism for cells of the reproductive tract. Langerhans' cells (LC), showed only minimal susceptibility to infection with HIV-1B from the US, but substantially greater sensitivity for infections by HIV-1 E and HIV-1 C, subtypes that predominate in Asia and Africa.

Acquired Immunodeficiency Syndrome↗

PubMed1996

HIV-1 pol sequences from India fit distinct subtype pattern.

HIV-1 isolates are classified phylogenetically in several subtypes or clades according to env and gag coding sequences. Viral subtypes tend to cluster geographically. DNA sequences encoding the p51 subunit of reverse transcriptase were obtained by nested polymerase chain reaction from peripheral blood mononuclear cells of two HIV-1-seropositive individuals from New Delhi and three from Pune, in northern and western India, respectively. These isolates were previously characterized as subtype C according to their env sequences. Based on phylogenetic analysis, the reverse transcriptase coding region of these isolates is distinct from those of subtype A, subtype B, subtype D, and group O of HIV-1 viruses. The nucleotide divergence of these Indian pol sequences (3.3%) is similar to that of existing sequences for subtype B and subtype D viruses. This result supports the epidemiologic data of a more recently introduced HIV-1 epidemic in India. Based on the corresponding env sequences, the pol sequences described in this report are subtype C.

Amino Acid Sequence↗

PubMed1996

HIV-1 Langerhans' cell tropism associated with heterosexual transmission of HIV.

Heterosexual transmission by vaginal intercourse accounts for most transmission of human immunodeficiency virus-type 1 (HIV-1) in Africa and Asia but is less important in the HIV-1 epidemics of the United States and Western Europe. Epithelial Langerhans' cells (LCs) represent a possible source of initial cell contact for vaginal infection. Fifteen primary isolates of HIV-1 from U.S. homosexuals and 18 HIV-1 isolates from Thailand heterosexuals were evaluated for growth in LCs of U.S. origin. All the viruses from the Thai heterosexuals, which were subtype E, grew more efficiently in the LCs than any of the viruses from the U.S. homosexuals, which are subtype B. These results suggest that LC tropism is associated with the efficiency of heterosexual transmission of HIV.

Cell Line↗

PubMed1995

Human T-lymphotropic virus type I (HTLV-I)-specific antibodies and cell-free RNA in crevicular fluid-rich saliva from patients with tropical spastic paraparesis/HTLV-I-associated myelopathy.

Despite the likely role of mucosae in human T cell leukemia virus type I (HTLV-I) transmission, little is known about the mucosal immune response to HTLV-I. The present study evaluated the antibody response to HTLV-I in oral mucosa and the value of crevicular fluid rich saliva (CFRS) for diagnosing HTLV-I infection. CFRS and sera from patients with tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM), asymptomatic carriers, and HTLV-I seronegative individuals from Tumaco, Colombia, were analyzed for HTLV-I specific IgG, IgA, and secretory IgA (sIgA). Detection of IgG in CFRS by enzyme-linked immunosorbent assay correlated with its presence in sera for TSP/HAM patients and asymptomatic carriers. IgA and sIgA were more frequently detected in CFRS and sera from TSP/HAM patients than in those from asymptomatic carriers. An HTLV-I pol fragment could be amplified from CFRS by reverse transcriptase-PCR in 3 TSP/HAM patients and one asymptomatic carrier, all of whom had an IgA response in CFRS but not in sera. The more frequent detection of IgA and sIgA in sera and CFRS of TSP/HAM patients suggests increased viral replication. Further, the association of viral RNA in CFRS with a local IgA response may signify rounds of viral replication in the oral cavity.

Antibody Specificity↗