Effect of thalidomide in different tumors in rodents

This study investigated the effects of chronic administration of thalidomide on three different neoplasms of ectodermic origin in rodents: 1) chemically induced tumors of the nervous system of rats by transplacental exposure to ethylnitrosourea; 2) transplanted RPMI-1846 melanoma in hamsters and 3) transplanted C6 glioblastoma in rats. No effects were seen on thalidomide-treated rats on the frequency- and time of tumor development induced by ethylnitrosourea. In contrast, a reduction in tumoral growth and mitotic-index was obtained in animals treated with thalidomide in transplanted tumors, melanoma and glioblastoma, when compared with controls (P < 0.001 and 0.025, respectively). These results suggest that, although thalidomide is not a cytotoxic drug for neoplastic cells, it might partially inhibit the tumoral growth through any of its pharmacological actions; by blockage of cell-surface adhesion receptors induction of DNA oxidation, or inhibition of angiogenesis. Further investigations on the use of thalidomide perhaps associated to cytotoxic drugs, for treatment of ectodermic neoplasms seem guaranteed.     

Association between cardiovascular disease and anti-Chlamydia pneumoniae antibodies

OBJECTIVE: To evaluate the association between cardiovascular disease (CVD) and antibodies against Chlamydia in Mexican population. MATERIAL AND METHODS: A cross-sectional study was conducted from August 1988 to April 2000, at the Immunology and Infectology Research Unit of Hospital de Infectología, Centro Médico Nacional La Raza (CMNR)--and at the Cardiovascular Surgery and Circulatory Care, Hospital General CMNR, Instituto Mexicano del Seguro Social (IMSS). Study subjects were 70 CVD hospitalized patients, older than 30 years, from both genders. Serum IgG and IgM antibodies against C. psitaccii, C. trachomatis and C. pneumoniae were determined by microimmunofluorescence in study subjects and compared with those from 140 healthy individuals, matched by age and sex. Simple random sampling was used, for an expected prevalence of 50% and a 99% confidence level; the sample size was 110 subjects. The chi-squared test and odds ratios were used to compare proportions. RESULTS: IgG antibodies against C. pneumoniae were found in 94.3% (66/70) patients, as compared to only 37% (52/140) of healthy individuals (p < 0.001). CONCLUSIONS: An association between IgG antibodies against C. pneumoniae and CVD was found. This finding warrants further studies to evaluate the role of C. pneumoniae as a predictor of CVD. The English version of this paper is available at: http://www.insp.mx/salud/index.html.     

Expression of CD44s and CD44 splice variants in human melanoma.

The ability of tumor cells to adhere and detach from extracellular matrix and endothelial cells, is a crucial step in the metastatic process and may alter the clinical prognosis of some human tumors such as melanomas. CD44, the major cell surface receptor for hyaluronate, has been implicated in cell adhesion and in tumor progression. We studied the expression of standard CD44 molecule (CD44s) and its variants v3 and v6 in 57 human primary melanoma biopsies, without previous treatment. We analyzed the association between CD44 expression and the principal clinicopathological features, including survival. Fifty-six of 57 tumors expressed CD44s, associated to the cytoplasmic membrane. No expression of CD44v3 or CD44v6 was detected. No association between CD44s expression and prognostic factors such as tumor thickness, growth type, stage or anatomic site of the lesion was found. However, a positive correlation between CD44s expression and Clark level (Spearman, p<0.001) was found. While only 33.3% of melanomas Clark I + II showed high expression of CD44s (more than 50% of positive cells), 82.6% of melanomas Clark IV + V did so. Kaplan-Meier analysis revelead that patients whose melanomas had high expression of CD44s showed a reduced relapse free survival (RFS) rate, though without statistical significance. No difference between the level of CD44 expression and overall survival (OS) was found. We conclude that melanomas only expressed CD44s, and that its level was associated with Clark's stage. CD44s seems not to be useful as a tumor marker, because it does not predict either RFS or OS.     

Incidence of leukemias in children from El Salvador and Mexico City between 1996 and 2000: Population-based data

Background

There are very few studies that report the incidence of acute leukemias in children in Latin America. This work assesses the incidence of acute leukemias, between 1996 and 2000, in children from 0–14 years old who were attended at the Mexican Social Security Institute in Mexico City and in children from 0–11 years old in El Salvador.

Methods

Design: Population-based data. Hospitals: In San Salvador, El Salvador, Hospital Nacional de Niños "Benjamín Bloom", the only center in El Salvador which attends all children, younger than 12 years, with oncologic disease. The Pediatric Hospital and the General Hospital of the Mexican Social Security Institute in Mexico City, the only centers in Mexico City which attend all those children with acute leukemia who have a right to this service. Diagnosis: All patients were diagnosed by bone marrow smear and were divided into acute lymphoid leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and unspecified leukemias (UL). The annual incidence rate (AIR) and average annual incidence rate (AAIR) were calculated per million children. Cases were stratified by age and assigned to one of four age strata: 1) <1 year; 2) 1–4 years; 3) 5–9 years, or 4) 10–14 or 10–11 years, for Mexico City and El Salvador, respectively.

Results

The number of cases was 375 and 238 in El Salvador and Mexico City, respectively. AAIRs in Mexico City were 44.9, 10.6, 2.5, 0.5, and 58.4 per million children for ALL, AML, CML, UL, and total leukemias, respectively. The AAIRs in El Salvador could not be calculated because the fourth age stratum in El Salvador included children only from 0–11 years old. The incidence rates for the Salvadoran group of 0–11 year olds were 34.2, 7.1, 0.6, 0.2, and 43.2 per million children for ALL, AML, CML, UL, and total leukemias, respectively.

Conclusion

Reported AIRs for each age group in El Salvador were similar to those from other American countries. The AAIR of ALL in Mexico City is one of the highest reported for North America.     

Pesticide exposure alters follicle-stimulating hormone levels in Mexican agricultural workers

Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas-liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic-pituitary endocrine function and also indicates that FSH and LH are the hormones most affected.     

Effect of zinc-treated Entamoeba histolytica on the human polymorphonuclear respiratory burst

One of the mechanisms that Entamoeba histolytica uses to evade host immune response is inhibition of the polymorphonuclear (PMN) leukocyte respiratory burst. In studies previously conducted in a model used in our laboratory, we observed that when treating trophozoites with different zinc concentrations certain amebic functions are inhibited while significantly limiting development of hepatic abscess in golden hamsters (Mesocricetus aureatus). We carried out an in vitro study using a chemoluminescent method to assess the effect zinc-treated amebic trophozoites exercise on respiratory burst in human PMNs. We measured response of PMNs incubated with E. histolytica trophozoites from cultures with TYI-S33 medium alone and with zinc. Zinc concentrations between 0.1 and 1.0 mM did not affect amebic trophozoite viability, and PMNs in contact with these in a zinc-free medium had an oxidative response similar to that obtained with zymosan and significantly greater (p <0.05) than that generated by cells co-incubated with amebas cultured in TYI-S33 medium alone. These results suggest that zinc alters the amebic mechanism that inhibits the oxidative function of human polymorphonuclear leukocyte.     

Is Iodine A Gatekeeper of the Integrity of the Mammary Gland?

This paper reviews evidence showing iodine as an antioxidant and antiproliferative agent contributing to the integrity of normal mammary gland. Seaweed is an important dietary component in Asian communities and a rich source of iodine in several chemical forms. The high consumption of this element (25 times more than in Occident) has been associated with the low incidence of benign and cancer breast disease in Japanese women. In animal and human studies, molecular iodine (I₂) supplementation exerts a suppressive effect on the development and size of both benign and cancer neoplasias. This effect is accompanied by a significant reduction in cellular lipoperoxidation. Iodine, in addition to its incorporation into thyroid hormones, is bound into antiproliferative iodolipids in the thyroid called iodolactones, which may also play a role in the proliferative control of mammary gland. We propose that an I₂ supplement should be considered as an adjuvant in breast cancer therapy.     

Hip ulcer secondary to foreign body reaction and vacuum-assisted closure therapy: report of a case

Patients who have a foreign body reaction are at risk of developing chronic ulcers secondary to necrosis, due to the inflammation present in the affected tissues or trauma, worsened by alterations in the vascular perfusion. These ulcers represent a therapeutic challenge for both physicians and patients.