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Biomedical subjects

M Meléndez

Publications and source records attributed to M Meléndez.

At least 19 recordsLinked to original sources
PubMed1998

Risk behaviors, HIV seropositivity, and tuberculosis infection in injecting drug users who operate shooting galleries in Puerto Rico.

This study was designed to assess HIV risk behaviors, HIV seroprevalence, and tuberculosis (TB) infection in shooting gallery managers in Puerto Rico. The subjects were 464 injection drug users (IDUs), of whom 12.5% reported managing shooting galleries. The median frequency of drug injection was higher in shooting gallery managers than in nonmanagers. A trend was observed for purified protein derivative (PPD) reactivity to increase according to the length of time spent as a gallery manager, but this trend was not statistically significant. However, anergy rates increased significantly with increase in the number of months spent as shooting gallery manager (p = .021). Multivariate analyses showed that IDUs reporting shooting gallery management experience of > or = 25 months were more likely to be infected with HIV. Prevention programs need to emphasize strategies to protect the health of shooting gallery clients and, in particular, shooting gallery managers. Additional studies are required to determine effective strategies for reducing the risk of HIV and TB infection in shooting galleries.

AIDS-Related Opportunistic Infections↗
PubMed1998

Abnormal immunological response to Mycobacterium tuberculosis antigens in a patient with chronic myelocytic leukemia and active tuberculosis.

The pathogenic mechanisms of immunosuppression leading to susceptibility of Mycobacterium tuberculosis (MT) infection in chronic myelocytic leukemia (CML) are not clear. To address this issue, we measured the proliferative response, variation of T cell subpopulations (CD4+, CD8+, TCR-V delta 2 and TCR-V beta 8 T cells) and the cytokine profile (IL-1 beta, IL-2, IL-4, IL-6, IL-10, TNF-alpha, IFN-gamma) after MT stimulation of peripheral blood mononuclear cells (PBMC) in a patient with concomitant CML and active pulmonary tuberculosis. The results were compared to four patients with active pulmonary tuberculosis and no other coexistent diseases. The immunologic response to phytohemagglutinin (PHA) was also evaluated. In contrast to controls, the CML PBMC failed to proliferate in response to MT antigens. Mycobacterium-reactive CD4+, V delta 2 and V beta 8 T cells did not expand after MT stimulation of the CML PBMC. In MT antigens-stimulated cultures from the CML patient, IL-2 was not produced and mild reduction of IL-1 beta and INF-gamma were observed. In contrast, IL-10 was markedly elevated in these cultures. Similarly, PHA-stimulated PBMC from the CML patient showed no expansion of CD4+ and CD8+. T cells. In these cell cultures, INF-gamma concentration in supernatants was decreased and IL-10 was significantly elevated. This study suggests that patients with CML may present a profound immunosuppression of essential cellular and molecular immune effectors, a scenario which might contribute to the development of active tuberculosis. These findings further support the need of establishing immunotherapeutic modalities with potential value for myeloproliferative disorders.

Adult↗
PubMed1996

Mycobacterium tuberculosis infection among crack and injection drug users in San Juan, Puerto Rico.

This study aims to determine the prevalence of Mycobacterium tuberculosis infection and its association with HIV and other health risk factors among drug users. A sample of 716 IDUs and crack users were enrolled from community sites. Consenting subjects were tested for HIV serum antibody status. Drug users with an unknown PPD status were administered a PPD skin test and an anergy panel of three antigens (Candida, mumps and tetanus). Overall, 68 (10.3%) were reactive to the PPD skin test, 240 (34.7%) were HIV positive and 195 (29.5%) showed cutaneous anergy. Participants infected with tuberculosis (TB) were more likely to be HIV seropositive, and to have a history of incarceration and residential drug treatment than those not infected. In addition, TB infection was more prevalent among intravenous drug users (IDUs) and shooting gallery managers. These findings suggest that drug users should be considered at high risk for TB and HIV infection. Innovative programs to monitor both infections among drug users are needed to arrest what can become a dual epidemic of HIV and TB in the near future.

Adult↗
PubMed1992

Physeal injuries in myelomeningocele patients.

Epiphysiolysis from a series of 253 patients under regular control in the Spina Bifida Unit at our hospital has been analysed from 1967 to the present time. From that total there have been 18 physeal fractures in 9 of the myelomeningocele patients. The clinical characteristics, diagnostic difficulties and therapeutic criteria for this type of lesion are considered, and we suggest the need to use suitable orthoses whenever the patient is able to walk, and to temporarily increase the level of orthotisation in patients if the physis of the knee is affected.

Adolescent↗
PubMed1979

Distribution of HLA histocompatibility antigens, ABO blood groups and Rh antigens in alcoholic liver disease.

The distribution of 16 antigens of the HLA-A and 15 antigens of the HLA-B series of HLA system, the blood groups ABO, and Rh antigens were studied in 40 alcoholics with cirrhosis, 18 alcoholics without cirrhosis, and in normal control subjects. The group of alcoholics with cirrhosis showed a significantly high frequency of HLA-B13 (corrected P less than 0.01) when compared with normal subjects, while the frequency of HLA-B13 was similar to normal in alcoholics without cirrhosis. On the basis of these findings, its seems that the carriers of HLA-B13 are more susceptible to liver damage caused by alcohol. Both groups of alcoholics and the normal controls had a similar distribution of ABO blood groups and Rh antigens.

ABO Blood-Group System↗
PubMed1978

Immunity to antigenically related salmonellae: effects of humoral factors on the bactericidal activity of normal and immune peritoneal exudate cells.

Immunity against Salmonella enteritidis and Listeria monocytogenes was studied by measuring in vitro the bactericidal activity of peritoneal exudate cells (PEC) of control (normal PEC) and S. typhi Ty2-immune (immune PEC) mice. Specific immune serum, anti-S. tyhphi Ty2, heat inactivated at 56 degrees C for 30 min, significantly inhibited the growth of S. enteritidis only with immune PEC. These opsonic factors had no effect upon the activity of normal PEC. That such inhibition could not be demonstrated in Listeria experiments, either with immune or normal PEC, suggests that S. enteritidis was specifically recognized, in vitro, by the thermostable opsonin anti-S. typhi Ty2 and that macrophages from immune PEC were more efficient in inhibiting bacterial growth than those from normal PEC. Thus, the interaction between macrophages and the microorganism seems to play an essential role in cell-mediated as well as humoral immunity.

Antibodies, Bacterial↗