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Biomedical subjects

A Mohar

Publications and source records attributed to A Mohar.

At least 37 records · Page 2Linked to original sources
PubMed1998

HPV prevalence among Mexican women with neoplastic and normal cervixes.

Genital human papillomavirus (HPV) infection is causally linked to cervical cancer, yet little is known regarding HPV prevalence in cancerous and normal women in Mexico, a country with a high cervical cancer incidence. We studied 185 Mexican women among the patients attending gynecological outpatient clinics in four hospitals in Mexico City. Each woman had a Pap smear, a colposcopy, and, when necessary, a biopsy. HPVs were identified by a consensus-primer-based polymerase chain reaction (PCR) assay. HPV was detected in 87% of 69 cancers, 83% of 24 high-grade squamous intraepithelial lesions (HGSILs), 33% of 21 low-grade squamous intraepithelial lesions (LGSILs), and 17% of 71 normals. Twenty-one of the 32 HPV types tested were detected at least once. The ratio of high-risk:low-risk types was 87:6 in HGSILs and cancers, compared to 11:8 for LGSILs and normals. In invasive cancers, HPV types found at the highest frequency were, in descending order: HPV-16, -18, and -45, followed by -39, -59, and -58 with the same frequency. HPV-16 and related types were present in 52% of the cancer cases, as well as in 79% of HGSILs, and HPV-18 and related types were present in 36% of the cancers but in only 12.5% of the HGSILs. HPV-16 was predominant in squamous carcinomas, and HPV-18 and related types were predominant in adenosquamous carcinoma. Both biopsies and scrapes were tested for HPVs in 63 women, all of them with cervical neoplasia. Identical HPV results were obtained in 89% of the samples, but additional types were often identified in scrapes. HPV prevalence and type distribution in cervical cancer in Mexico was similar to the reported worldwide, as well as in other Latin American countries.

Carcinoma, Adenosquamous↗
PubMed1997

Dichlorodiphenyltrichloroethane serum levels and breast cancer risk: a case-control study from Mexico.

Some, but not all, epidemiological studies have suggested that dichlorodiphenyltrichloroethane (DDT) may play a role in the development of breast cancer. These investigations have been conducted in countries where this substance has been banned for at least 20 years. We conducted a study in Mexico, a country in which DDT is still being used to control malaria. In a hospital-based case-control study, we compared 141 histologically confirmed cases of breast cancer with 141 age-matched controls (+/-3 years). All subjects were identified at three referral hospitals of Mexico City between March 1994 and April 1996. Reproductive histories and other variables were obtained by structured interviews, DDT/DDE levels were determined in serum by gas-liquid chromatography. The arithmetic mean of serum DDE in lipid basis was 562.48 +/- 676.18 ppb (range, 10.24-4661.44) for the cases and 505.46 +/- 567.22 ppb (range, 0.004 to 4361.75) for the controls, but this difference was not statistically significant. The age-adjusted odds ratios for breast cancer regarding the serum level of DDE were 0.69 (95% confidence interval, 0.38-1.24) and 0.97 (confidence interval, 0.55-1.70) for the contrasts between tertile 1 (lowest level) and tertiles 2 and 3, respectively. These estimates were unaffected by adjustment for body mass, accumulated time of breast-feeding and menopause, and other breast cancer risk factors. These results do not lend support to the hypothesis that DDT is causally related to breast cancer at the body-burden levels found in our study population but do not exclude the possibility that higher levels of exposure could still play a role in the etiology of this tumor.

Adult↗
PubMed1997

Intestinal type: diffuse type ratio of gastric carcinoma in a Mexican population.

This study was performed in order to define the histological patterns of gastric carcinoma according to Lauren's classification and the IT:DT ratio in a Mexican population. We analyzed the relative frequency of intestinal-type and diffuse-type carcinomas in a group of patients, diagnosed at the Instituto Nacional de Cancerologia in Mexico City between 1982 and 1992. Of the 460 cases of gastric cancer, 242 (52.7%) were of the intestinal-type, 206 (44.7%) of the diffuse type, and 12 (2.6%) others. A predominance of the diffuse type among the younger age groups (< 50 years) was observed-the transitional age for men and women occurred in the sixth decade. The global intestinal: diffuse ratio was 1.2 and increased with age. This ratio remained similar during the 11 years of the analysis. Men had a higher proportion of intestinal type carcinoma than women. These findings indicate that Mexico is not a low risk area for gastric cancer with a consistently low intestinal: diffuse type ratio. Despite differences in geographic and demographic patterns, the intestinal and diffuse types of gastric carcinoma have common etiological factors.

Adult↗
PubMed1997

Basal cell carcinoma of trunk and extremities.

BACKGROUND: Basal cell carcinoma is the most common malignancy in Caucasians. Information about basal cell carcinoma in the Mexican population is scarce. OBJECTIVE: To determine the epidemiologic and clinical characteristics and treatment results of basal cell carcinoma located on the trunk and extremities of patients seen at the Instituto Nacional de Cancerología of Mexico. METHODS: A retrospective study was performed of patients with confirmed diagnosis of basal cell carcinoma located on the trunk and extremities seen at the Instituto Nacional de Cancerología of Mexico between 1966 and 1993. RESULTS: Ninety-one patients with basal cell carcinoma located on the trunk and extremities were found (6% of all patients with diagnosis of basal cell carcinoma). The median age was 64 years; 52% of the patients were women and 48% were men. A total of 119 basal cell carcinomas at these locations were diagnosed. The size of the skin tumor ranged from 0.3 to 22 cm (mean, 3.9 cm). Treatment results were evaluated in 62 patients (follow-up ranged from 24 to 240 months; mean, 80 months). Overall tumor control was accomplished in 95% of cases. Three patients died as a result of basal cell carcinoma. CONCLUSIONS: Basal cell carcinoma in the Mexican population is not as infrequent as previously thought, although it is less commonly located on the trunk and extremities than in Caucasians.

Adult↗
PubMed1997

[Lymphoma].

Explore the source record for details and available documents.

Adult↗
PubMed1996

Chemotherapy-associated oral mucosal lesions in patients with leukaemia or lymphoma.

In order to determine the incidence rate of oral lesions associated with chemotherapy, as well as well as its association with clinical and laboratory parameters and potential risk factors, 50 in-patients with non-Hodgkin's lymphoma or leukaemia under chemotherapy were followed from January 1993 to May 1994. Basal and weekly oral examinations were performed. Clinical and laboratory data were registered. Wilcoxon's rank sum test, chi square test, univariate and multivariate logistic regression analyses were used, 36 individuals with leukaemia and 14 with non-Hodgkin's lymphoma were followed for 158 weeks; mean age was 33 years (range 15-85). Oral lesion incidence rate was 45/100 patients-week. Exfoliative cheilitis and infections (herpes and candidosis) were the most common oral complications, followed by haemorrhagic lesions and mucositis. Haemorrhagic lesions correlated with thrombocytopenia (RR = 30.5). Etoposide administration (RR = 8.6), alkylating agents (RR = 15.6), a prior course of chemotherapy (RR = 23.2) and neutropenia (RR = 4.16) were predictors of mucositis. Oral lesions were a common complication in this study, and a possible association of mucositis with several factors is suggested.

Adolescent↗
PubMed1995

Association of Epstein-Barr virus latent membrane protein and Hodgkin's disease in Mexico.

Epstein-Barr virus (EBV) has been demonstrated in association with Hodgkin's disease (HD) in approximately 40 to 50% of cases in series from North America, Europe, and Japan. However, few data are available concerning this association in developing countries. Recent studies, including mostly a pediatric population from Peru and a pediatric population from Honduras, showed a higher percentage of EBV positivity compared with those in developed countries. To determine the prevalence of EBV in Hodgkin's disease in a Mexican adult population, we analyzed 50 formalin-fixed, paraffin-embedded cases of HD by a three-step technique using a monoclonal antibody to the latent membrane protein of EBV. All the cases were confirmed immunophenotypically as HD (CD15+ and/or CD30+, CD45-). Reed-Sternberg cells and variants were positive for LMP in 35 cases (70%). The staining was found both on the cell surface and/or within the cytoplasm with enhancement of the Golgi area. EBV latent membrane protein was found in 1/1 case (100%) of diffuse lymphocyte-predominant HD, 10/20 cases (50%) of nodular-sclerosis, 18/22 cases of mixed-cellularity (81%), and 6/7 (86%) cases of lymphocyte-depleted HD. Our results show a high prevalence of EBV in HD in this Mexican adult population. All histologic subtypes of HD in the population analyzed appear to be strongly associated with EBV, in contrast to the strong association of mixed cellularity HD in developed countries. Patient age and gender were not predictive of the presence of EBV.

Adolescent↗
PubMed1994

Experience of an intravenous therapy team at the Instituto Nacional de Cancerología (Mexico) with a long-lasting, low-cost silastic venous catheter.

Means of vascular access are fundamental in the management of cancer. However, since current intravenous devices for long-term treatment are expensive and necessitate a high degree of education among medical personnel, in developing countries they are impractical for use in most of the population. We describe the use of a nontunneled, low-cost, long-lasting Silastic catheter (LLSC), cared for by an intravenous therapy team (IVTT), in 462 patients with cancer. The rate of infectious complications was 0.66 infections per 1,000 catheter-days, which is as low as that reported in association with other catheters in developed countries. Neutropenia and skin and/or soft-tissue infections were significant risk factors associated with LLSC-related infections. We believe that use of this catheter may be an alternative for patients with cancer who need chemotherapy, as long as an IVTT is established for its care. Our experience could be useful for practitioners in countries with similar socioeconomic characteristics.

Antineoplastic Agents↗
PubMed1994

Hippocampal involvement associated with human immunodeficiency virus encephalitis in Mexico.

The objective of the present study was to review the alterations of the central nervous system (CNS) in a group of deceased Mexican patients with acquired immunodeficiency syndrome; autopsies were reviewed with a special emphasis on the damage to the hippocampal formation. Of these 19 deceased patients with acquired immunodeficiency syndrome, nine (47%) had opportunistic infections in the CNS that were accompanied by human immunodeficiency virus encephalitis (HIVE), three (16%) had evidence of opportunistic infections in the brain without HIVE, and two (11%) had HIVE alone. All of the patients who had presented with neurological and neurobehavioral alterations had evidence of HIVE and/or opportunistic infections in the CNS. Of these 19 patients, 11 (58%) had presented with evidence of HIVE (with or without opportunistic CNS infections), as evidenced by the presence of gp41-positive microglial cells in the basal ganglia, neocortex, and hippocampus. The subiculum was the region that displayed the most abundant infiltration by gp41-positive microglial cells. The percentage of cases of acquired immunodeficiency syndrome with HIVE and/or CNS opportunistic infections in our series was similar when compared with that of other series in which similar methods of detection of human immunodeficiency virus in the CNS were used. We conclude that evidence of human immunodeficiency virus-associated lesions in the hippocampal formation might in part explain the selective neuronal alterations in this limbic structure, and we suggest that damage to this circuitry might be in part involved in the cognitive alterations in HIVE.

AIDS-Related Opportunistic Infections↗
PubMed1993

The association of Helicobacter pylori with gastric cancer and preneoplastic gastric lesions in Chiapas, Mexico.

BACKGROUND: Helicobacter pylori recently was identified as a risk factor for gastric cancer. Its association with preneoplastic conditions of the stomach, however, is undocumented. METHODS: Gastric biopsy specimens from 245 symptomatic patients were examined for neoplastic and preneoplastic lesions and for gastric H. pylori infection. The sera of 183 subjects were tested by enzyme-linked immunosorbent assay (ELISA) for anti-H. pylori immunoglobulin G. RESULTS: Histologic H. pylori infection, usually accompanied by acute and chronic gastritis, was found in 85.7% of patients. There was a strong association between H. pylori in the tissue and atrophy (relative risk, 15.0; 95% confidence interval, 4.2-56.6), intestinal metaplasia (relative risk, 5.7; 95% confidence interval, 1.9-16.8), and dysplasia or cancer (relative risk, 4.0; 95% confidence interval, 1.1-14.8). The ELISA was 93.2% sensitive and 57.1% specific for histologic infection with a positive predictive value of 96.1%. The overall seroprevalence rate was 86.1%, with no significant difference in rates between patients with cancer precursors and those with normal stomachs. CONCLUSIONS: In this high-risk population, precursor lesions for adenocarcinoma were associated universally with H. pylori infection.

Adult↗
PubMed1993

Oral findings in Mexican AIDS patients with cancer.

Oral findings of 42 Mexican AIDS patients with cancer were reviewed. Kaposi's sarcoma (KS) was the most frequent malignancy (81%) followed by non-Hodgkin's lymphoma (NHL) (12%). All cases of NHL were of high or intermediate grade and most of them were extranodal. Out of the 34 individuals with KS, 22 (65%) showed oral KS and in 21 of them the palate was involved. The clinical features of oral KS including site, appearance and size are described. Pseudomembranous candidosis (PC), hairy leukoplakia (HL) and exfoliative cheilitis (ECh) were also found in these patients. There was no association of these lesions with any type of cancer. A strong association of oral candidosis and history of this infection was found, RR = 7.0 (1.3-4.1). There was evidence of severe immunosuppression in most patients, with mean average CD4 counts of 116 mm3 (range 4-841/mm3). Oral KS, ECh, PC and HL were more common in patients with lower CD4 counts. Our findings illustrate the most frequent oral lesions associated with HIV-1 infection in patients with AIDS and cancer, and further support the importance of oral examination in HIV infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1992

Viruses other than HIV and non-Hodgkin's lymphoma.

There are several viral infections which are known to cause lymphoma among animals; all establish latency in lymphoid cells. The human T-lymphotropic virus type I is a human virus which causes lymphomas among a subset of carriers. However, this virus is very restricted in its distribution and as such, is unlikely to play a role in the increase of non-Hodgkin's lymphoma (NHL). A highly prevalent infection, the Epstein-Barr virus (EBV) is known to play a role in the etiology of NHL among persons with acquired or inherited immune suppression. However, whether it is involved with "spontaneous" NHL is unknown. We have found evidence that among a group of 104 NHL patients with blood samples taken several years before diagnosis, there was an alteration in the antibody profile against the EBV which is quite similar to that seen for immune-suppressed patients prior to their diagnosis. This pattern is most evident in the oldest patients. This suggests that there may be an age-related subclinical immune suppression leading to chronic activation of EBV. If a viral infection is a major factor in the recent increase in NHL in the world, then we should consider the role of immune-suppressive exposures which have become widespread in recent decades.

Adult↗
PubMed1992

Constitutional translocation (8;13) in a patient with non-Hodgkin's lymphoma.

We report a case of non-Hodgkin's lymphoma in a 16-year-old male, whose peripheral white blood cells have a t(8;13)(q24;q14). There are no previous reports that describe this association. Although the tumor cells were not studied, we discuss the possible link between this finding and the development of the malignant lymphoma.

Adolescent↗
PubMed1992

The spectrum of clinical and pathological manifestations of AIDS in a consecutive series of autopsied patients in Mexico.

OBJECTIVE: Little is known about the clinical profile of AIDS in Latin American populations. This study characterizes the clinical and pathological manifestations of AIDS in a representative series of Mexican AIDS patients at autopsy. DESIGN: The clinical and pathological findings were abstracted retrospectively for a sequential series of autopsied AIDS patients. SETTING: Autopsies were conducted at the four major tertiary level hospitals that serve the majority of AIDS patients in Mexico City. PATIENTS: Subjects included 177 consecutive patients diagnosed with AIDS between March 1984 and January 1989 who subsequently died and were autopsied in the same period in the study hospitals. MAIN OUTCOME MEASURES: Demographic characteristics, including age, gender, residence, socioeconomic status, and risk group; clinical presentation and autopsy findings, including opportunistic infections and malignancies. RESULTS: Sixty per cent of the AIDS patients presented with wasting syndrome. The most common infections were cytomegalovirus (69%), tuberculosis (25%), and Pneumocystis carinii pneumonia (24%). Central nervous system infections were also common and included toxoplasmosis (19%) and cryptococcoses (10%). Kaposi's sarcoma was present in 30% of cases and non-Hodgkin's lymphoma in 9%. CONCLUSION: Clinical manifestation, and types and frequency of opportunistic infections in our Mexican AIDS patients were more similar to those seen in AIDS patients in Africa and Haiti than in the United States and Europe. These findings suggest that the AIDS epidemic in Mexico has an 'intermediate' pattern and may be a prototype for Latin American countries.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A model for the AIDS epidemic in Mexico: short-term projections.

As in many developing countries, the AIDS epidemic in Mexico has become a major public health problem. Given the competition for scarce health resources in Mexico, where hospitals are overcrowded and care for AIDS patients is often unavailable, planning depends on accurate estimates of the incidence of AIDS and the prevalence of HIV-1 infection. This article presents estimates of AIDS incidence in Mexico corrected for delays in reporting and short-term projections based on the corrected AIDS incidence. Trends in incidence cannot be assessed without such correction because only about 50% of AIDS cases are reported within 4 months of diagnosis. In addition to information on AIDS incidence, short-term projections also require estimates of the latency distribution between infection with HIV-1 and onset of AIDS. Latency periods with medians of 8 and 10 years lead to estimates that 22,000 and 24,000 new AIDS cases infected before June 1989 will be diagnosed between 1989 and 1994.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Epstein-Barr virus antibody patterns preceding the diagnosis of non-Hodgkin's lymphoma.

Immunosuppressed patients who develop non-Hodgkin's lymphoma (NHL) have abnormal antibody responses against the Epstein-Barr virus (EBV) prior to the diagnosis of malignancy. To see if this is also true of "spontaneous" cases in the general population, we undertook a collaborative serologic case-control study. From 4 serum banks containing specimens from over 240,000 persons, 104 subjects were identified for whom a blood specimen had been stored an average of 63 months before diagnosis of NHL, and 259 controls matched for age, sex, ethnic group and date of serum collection. The relative risks (RR) for subsequent development of NHL associated with elevated levels of IgG and IgM antibodies against viral capsid antigen were 2.5 (95% confidence interval = 1.1-5.7) and 3.2 (1.3-7.5), respectively; these associations increased with age at diagnosis. For the nuclear antigen, the distribution of titers for cases was more restricted than that of controls, with fewer cases having either elevated or low titers, RR = 0.5 (0.2-1.4) and 0.5 (0.2-1.2), respectively. Cases had significantly lower antibody titers against the cytomegalovirus, RR = 0.4 (0.2-0.9). These findings suggest that, at least for some patients, NHL is preceded by an enhanced level of endogenous immunosuppression with resultant EBV activation. This observation supports the role of EBV either directly in the development of NHL or as a primary marker of immune dysfunction.

Adult↗
PubMed1991

Modeling the AIDS epidemic in Mexico City.

To study the future course of the AIDS epidemic in Mexico City, we use an open compartmental model to forecast new AIDS cases among homosexual and bisexual males and among heterosexual males and females. For each group three compartments are defined: uninfected persons, infected but asymptomatic persons, and persons diagnosed with AIDS. It is assumed that the AIDS epidemic will follow the propagation of infectious disease model, where spread of infection is proportional to the product of the number of healthy persons and the number of infected ones. The compartmental model is represented by a system of nonlinear differential equations describing the rate of change in the number of persons in each compartment. The impact of preventive measures is explored by decreasing the probability of HIV transmission, which is one of the model parameters representing behavioral patterns. By April 1989, 491 AIDS cases had been reported in Mexico City and classified as sexually related. Our model predicts that the AIDS incidence will continue to rise in Mexico City for the foreseeable future and will spread among the heterosexual population. Decreasing the transmission probability by 10% in all groups (through education programs) will result in a decrease of 18.1% in the number of accumulated cases over a 5-year period. A 20% decrease would prevent more than 31% of the cases. We conclude that mathematical models can be valuable in predicting the spread of the AIDS epidemic and the impact of behavioral change on its spread.

Acquired Immunodeficiency Syndrome↗