Environmental factors associated with blood lead levels in Venezuelan children

A preliminary study explored the relative contribution of residential sources of lead exposure on mentally challenged children who attend "special education" institutions (GI) compared to a group of age and sex matched school children (G2). We captured descriptive information and analyzed demographic variables, personal and household information, medical effects, environmental exposure factors, and children habits. Home paint, dust, soil, and water sampling was conducted and blood lead (BPb) levels determined. Eighteen G1 and 20 G2 children were studied. The mean G1 BPb was 16.9 +/- 7.9 microg/dl and was significantly higher than that in G2. Fifty percent of G1 children had PbB >20 microg/dl and 72.2% were >10 microg/dl. Low muscular strength, decreased osteotendinose reflexes, fine and gross motricity, deficient equilibrium, and hipotonic muscular tone coincided with >18 microg/dl BPb levels. In 61.1% of G1 homes paint lead levels were higher than permissible levels and 33.3% had dust lead exceeding that level. The high BPb levels in G1 probably resulted from ingestion of household paint, dust, and soil via "hand-to-mouth" activity. Environmental exposure to lead can be an important source of lead intake by infants and children and could affect neurological development. This study provides new insights currently unavailable for these children in Venezuela.

Extending the CD4(+) T-cell epitope specificity of the Th1 immune response to an antigen using a Salmonella enterica serovar typhimurium delivery vehicle

We analyzed the CD4 T-cell immunodominance of the response to a model antigen (Ag), MalE, when delivered by an attenuated strain of Salmonella enterica serovar Typhimurium (SL3261*pMalE). Compared to purified MalE Ag administered with adjuvant, the mapping of the peptide-specific proliferative responses showed qualitative differences when we used the Salmonella vehicle. We observed the disappearance of one out of eight MalE peptides' T-cell reactivity upon SL3261*pMalE immunization, but this phenomenon was probably due to a low level of T-cell priming, since it could be overcome by further immunization. The most striking effect of SL3261*pMalE administration was the activation and stimulation of new MalE peptide-specific T-cell responses that were silent after administration of purified Ag with adjuvant. Ag presentation assays performed with MalE-specific T-cell hybridomas showed that infection of Ag-presenting cells by this intracellular attenuated bacterium did not affect the processing and presentation of the different MalE peptides by major histocompatibility complex (MHC) class II molecules and therefore did not account for immunodominance modulation. Thus, immunodominance of the T-cell response to microorganisms is governed not only by the frequency of the available T-cell repertoire or the processing steps in Ag-presenting cells that lead to MHC presentation but also by other parameters probably related to the infectious process and to the bacterial products. Our results indicate that, upon infection by a microorganism, the specificity of the T-cell response induced against its Ags can be much more effective than with purified Ags and that it cannot completely be mimicked by purified Ags administered with adjuvant.

Immune responses induced by recombinant BCG strains according to level of production of a foreign antigen: malE

A variety of viral, bacterial and parasitic antigens have been expressed in BCG and the capacity of these recombinant bacteria to induce immune responses has been well documented. However, little is known about the parameters influencing the induction of immune responses by recombinant BCG (rBCG), such as level of production and localization of the recombinant antigen. In the present study, we have constructed several rBCG strains expressing the malE gene from Escherichia coli which is either secreted or targeted to the cytoplasm or plasma membrane. Expression of malE was quantified by ELISA and localization was analyzed by flow cytometry. Even when using the same promoter, levels of cytoplasmic or membrane MalE production were far less than those from secreting strains using either mycobacterial or E. coli secretion signals. Stronger and more rapid immune responses were induced by rBCG strains with the highest levels of secreted MalE compared to cytoplasmic or membrane constructs, including both good humoral and proliferative responses in BALB/c, C57BL6 and even C3H mice, previously shown to be poor MalE responders. These results suggest that the levels of foreign antigen production play an important role in the induction of immune responses by rBCG strains.

Genomic compatibility between two phyllotine rodent species evaluated through their hybrids

In order to investigate the genomic compatibility between allopatric rodent species, Phyllotis darwini and Phyllotis magister, we have studied several cytogenetic and reproductive features of their laboratory hybrids. Of thirty-one pairings between species, only five were successful, producing eleven newborns. Like parents, hybrids had 38 metacentric chromosomes, except for the subtelocentric Y chromosome inherited from P. magister. There was almost total C and G band correspondence between homeologous autosomes. However, parental sex chromosomes had different morphology, C and G bands. Ag-NOR bands appeared as small telomeric Ag+ regions, distributed in four chromosomal pairs of darwini, three of magister and four homeologous chromosomes of the hybrids. The three forms had similar indexes of NOR activity per cell, in spite of the variability in NOR expression which was always detected. Usually, only one member of parental homologous chromosomes showed AgNOR+; nevertheless, both homeologous chromosomes were active in many hybrid cells. The frequencies of cells that expressed their ribosomal genes in the two homologous or homeologous NOR chromosomes were similar in parental and hybrid cells. These results strongly suggest that ribosomal genes of both parental genomes would function codominantly in the hybrids. The gonad histological and morphometric analyses showed that hybrids conformed to Haldane's rule, since females were fertile and males were infertile. Our results indicate that P. darwini and P. magister genomes can function in relative harmony and compatibility when they are placed together in their laboratory generated hybrids, suggesting that these species have few genetic differences, probably because they have recently diverged.

Sustained response to combination therapy in a patient with chronic hepatitis C and thrombocytopenia secondary to alpha-interferon

Recent data suggest that hepatitis C viral (HCV) infection may induce a significant autoimmune reaction to platelets, but the mechanism is unknown. Many patients with chronic hepatitis C, in fact, have high levels of platelet-associated immunoglobulin G (PAIgG) and HCV-RNA is present in the platelets of 100% of those patients with thrombocytopenia and high PAIgG levels. Hepatitis C virus infection has been associated with the development of thrombocytopenic purpura, sometimes triggered during interferon (IFN) therapy. In such cases, the treatment of the underlying disease is a difficult problem to solve. We report the case of a patient with chronic hepatitis C, who developed life-threatening thrombocytopenic purpura after a prolonged course of IFN-alpha2b over a 4-year period. Treatment with anti-immunoglobulin gammaglobulin (Polyglobin; Química Farmaceutica Bayer, Barcelona, Spain) had a transient effect on the platelet count, but prolonged therapy with prednisone was necessary for definitive relief of the haematological complication. Two years later, the patient was treated with combined therapy, including ribavirin (1200 mg/day) and IFN-alpha2b (5 mU, t.i.w.) for 12 months. This therapy induced a sustained response, both biochemical and virological, without haematological complications. This observation suggests that ribavirin may be of benefit in the treatment of immune-mediated thrombocytopenia in patients with chronic hepatitis C, preventing the harmful effect of IFN-alpha but also allowing both drugs to be combined so as to increase the probability of sustained remission of the liver disease.

Delivery of CD8(+) T-cell epitopes into major histocompatibility complex class I antigen presentation pathway by Bordetella pertussis adenylate cyclase: delineation of cell invasive structures and permissive insertion sites

Bordetella pertussis adenylate cyclase (AC) toxin-hemolysin (ACT-Hly) can penetrate a variety of eukaryotic cells. Recombinant AC toxoids have therefore been recently used for delivery of CD8(+) T-cell epitopes into antigen-presenting cells in vivo and for induction of protective antiviral, as well as therapeutic antitumor cytotoxic T-cell responses. We have explored the carrier potential of the ACT molecule by insertional mutagenesis scanning for new permissive sites, at which integration of two- to nine-residue-long peptides does not interfere with membrane interaction and translocation of ACT. A model CD8(+) T-cell epitope of ovalbumin was incorporated at 10 of these permissive sites along the toxin molecule, and the capacity of ACT constructs to penetrate into cell cytosol and deliver the epitope into the major histocompatibility complex (MHC) class I antigen processing and presentation pathway was examined. While all six constructs bearing the epitope within the Hly portion of ACT failed to deliver the epitope to the MHC class I molecules, all four toxoids with inserts within different permissive sites in the AC domain efficiently delivered the epitope into this cytosolic pathway, giving rise to stimulation of a specific CD8(+) T-cell hybridoma. The results suggest that, in contrast to the AC domain, the hemolysin moiety of ACT does not reach the cytosolic entry of the MHC class I pathway.

Modulation of benzo[a]pyrene diolepoxide-DNA adduct levels in human white blood cells by CYP1A1, GSTM1 and GSTT1 polymorphism

The modulation of benzo[a]pyrene diolepoxide (BPDE)-DNA adduct levels by polymorphisms in the CYP1A1, GSTM1 and GSTT1 genes was assessed in leukocytes of Caucasian males. Eighty-nine coke oven workers (35 smokers, 36 ex-smokers and 18 non-smokers) were recruited from job categories with different exposure levels to polycyclic aromatic hydrocarbons (PAH), together with 44 power plant workers (all smokers) not exposed to PAH. BPDE-DNA adducts were detected in 69 of 133 (52%) DNA samples with a 100-fold variation (range 0.2-44 adducts/10(8) nt) and a median of 1.6 adducts/10(8) nt. All samples with the GSTM1 active genotype (n = 59) and five out of 74 samples with GSTM1*0/*0 (7%) showed non-detectable adducts (<0.2 adducts/10(8) nt) and 69 of 74 subjects with GSTM1*0/*0 (93%) had detectable adducts (>0.2 adducts/10(8) nt). The difference in adduct level between the GSTM1*0/*0 and GSTM1 active genotypes was highly significant (P < 0.0001). No significant difference in adduct level between the GSTT1*0/*0 and GSTT1 active genotypes was seen. All heterozygotes (CYP1A1*1/*2) from subjects of GSTM1 active type did not have detectable adducts. Among the GSTM1-deficient individuals (n = 69), 42 with the CYP1A1*1/*1 genotype showed a lower adduct level (median 1.3, range 0.2-4.1 adducts/10(8) nt) compared with 26 individuals with heterozygous mutated CYP1A1*1/*2 genotypes (median 2.5, range 0.4-6.1 adducts/10(8) nt, P < 0.015). One individual with low PAH exposure and the rare combination CYP1A1*2A/*2A-GSTM1*0/*0 showed an extremely high level of 44 adducts/10(8) nt. Significant differences in detectable adduct levels were found between the CYP1A1*1/*1 and CYP1A1*1/*2 genotypes in the exposed group low + medium (P = 0.01) and for all adduct levels, detectable and non-detectable (set at a fixed value), in highly exposed individuals and in ex-smokers (P = 0.03), whereas no such differences were observed in the control group. Mutated CYP1A1*1/*2 increased the adduct level in non-smokers from the exposed group (1.4 versus 2.2 adducts/10(8) nt), but had no effect on the smokers from the exposed group (2.3 versus 2.8 adducts/10(8) nt). When all variables were dichotomized, statistical evaluation showed that CYP1A1 status (P = 0.015), PAH exposure (P = 0.003) and smoking (P = 0.006) had significant effects on adduct levels which increased in the order: CYP1A1*1/*1 < CYP1A1(*1/*2 or *2A/*2A); environmental exposure < occupational exposure; non-smokers < smokers, whereby adducts increased with cigarette dose and the duration of smoking. Higher levels of BPDE-DNA adducts in individuals with the combined CYP1A1(1/*2 or *2A/*2A)-GSTM1*0/*0 genotype suggest that these genotype combinations are at increased risk for contracting lung cancer when exposed to PAH.

Genetic polymorphism of CYP genes, alone or in combination, as a risk modifier of tobacco-related cancers

Tobacco use is causally associated with cancers of the lung, larynx, mouth, esophagus, kidneys, urinary tract, and possibly, breast. Major classes of carcinogens present in tobacco and tobacco smoke are converted into DNA-reactive metabolites by cytochrome P450 (CYP)-related enzymes, several of which display genetic polymorphism. Individual susceptibility to cancer is likely to be modified by the genotype for enzymes involved in the activation or detoxification of carcinogens in tobacco and repair of DNA damage. We summarize here the results of case-control studies published since 1990 on the effects of genetic variants of CYP1A1, 1A2, 1B1, 2A6, 2D6, 2E1, 2C9, 2C19, 17, and 19 alone or in combination with detoxifying enzymes as modifiers of the risk for tobacco-related cancers. The results of studies on gene-gene interactions and the dependence of smoking-related DNA adducts on genotype were also analyzed. Some CYP variants were associated with increased risks for cancers of the lung, esophagus, and head and neck. The risk was often increased in individuals who also had GSTM1 deficiency. For breast cancer in women, a few studies suggested an association with CYPs related to metabolism of tobacco carcinogens and steroidal hormones. The overall effects of common CYP polymorphisms were found to be moderate in terms of penetrance and relative risk, with odds ratios ranging from 2 to 10. Some CYP1A1/GSTM1 0/0 genotype combinations seem to predispose the lung, esophagus, and oral cavity of smokers to an even higher risk for cancer or DNA damage, requiring, however, confirmation. Future strategies in molecular cancer epidemiology for identifying such susceptible individuals are discussed with emphasis on well-designed larger studies.

Genetic cancer susceptibility and DNA adducts: studies in smokers, tobacco chewers, and coke oven workers

Preventive strategies require identification of cancer-susceptible individuals resulting from combinations of carcinogen exposure, cancer-predisposing genes, and lack of protective factors. To this aim, related to tobacco smoking and chewing (betel quid), we measured PAH-DNA adducts as exposure and susceptibility markers together with genetic polymorphism in drug-metabolizing enzymes related to CYP1A1, GSTM1, and GSTT1 genes in case-control studies. (+)-anti-Benzo(a)pyrene diol-epoxide (BPDE)-DNA adduct levels were quantitated in white blood cells (WBCs) and lung tissue DNA. CYP1A1 polymorphism and GSTM1 or GSTT1 gene deletion was analyzed in genomic DNA from lung parenchyma, WBCs, or oral biopsies (leukoplakia patients from India) and from oral exfoliated cells (healthy controls). Results from lung cancer patients and PAH-exposed coke oven workers correlated CYP1A1-GSTM1 genotype combinations with BPDE-DNA adduct levels. Smokers with homozygous CYP1A1 variant and GSTM1 null had the highest adduct levels and were, as shown in Japanese smokers, most susceptible to lung cancer. In oral premalignant leukoplakia cases associated with betel quid/tobacco chewing, the prevalence of the GSTM1 null and GSTT1 null genotypes was significantly higher, as compared to healthy controls. The combined GST null genotypes prevailed in 60% of the cases with none detected in controls. Based on this short review we conclude that (i) BPDE-DNA adduct levels resulting from "at risk" genotype combinations may serve as markers to identify most susceptible individuals; (ii) in Indian betel quid/tobacco chewers, the null genotypes of GSTM1 and GSTT1 greatly increased the risk for developing oral leukoplakia.

Pesticide exposure in a farming village in Venezuela--a developing country

This study was designed and performed by the Universidad de Carabobo, Centro de Investigaciones Toxicológicas, Venezuela, and the University of Cincinnati Department of Environmental Health. The authors tested methodology and analyzed preliminary data on demographics, pesticide use, health, environment, and lifestyles in a farming community in Venezuela (population = 386; sample size = 81) to determine if pesticide misuse might have been contributing to public health problems. Questionnaire and geographic information were collected. There were statistically significant incidences of pesticide-related symptoms (p < .01) in farmers versus nonfarmers (odds ratio = 5.7; 95% confidence interval = 2.9, 18.8). In addition, in one area there was a cluster of farmers who experienced symptoms that appeared to be the result of foul air and proximity to farms where there was pesticide use. The results of the study indicated that this public health problem may have been associated with pesticide misuse; however, additional studies are needed to corroborate the findings.

Defecation practices of young children in a Peruvian shanty town

Little is known about feces disposal practices, their determinants and feasibility for change, despite their importance in the control of diarrheal diseases. We report here the results of formative research for the development of an intervention to promote sanitary disposal of feces of young children. The study was conducted in a densely populated shanty town area of Lima, where water and sanitation systems are scarce. In-depth interviews were undertaken with mothers, husbands and community leaders. Group discussions were held with mothers in order to validate findings from the interviews, investigate particular topics further and explore reactions to possible intervention strategies. The principal defecation sites for young children were diapers, potties, the ground in or near the home, the hill, latrines and flush toilets. The main determinants found were the age of the child, the effort required by the method, perceptions of dirtiness and the availability of resources. Almost all children under one year of age use diapers but the high resource cost of diaper washing is a strong motivation for mothers to move their children on as early as possible. Potties were considered the most socially acceptable and 'hygienic' defecation method for children between one and three years of age. Nevertheless, defecation directly onto the ground is common at this age. Potty training is deemed to be quite difficult and the long term achievements are determined by the initial training success. In most cases, the training process is authoritative and inconsistent. The use of latrines and flush toilets is not considered appropriate for children until they are three to four years old. Based on these initial findings, a micro-trial was conducted to assess the feasibility and acceptability of promoting greater use of potties and associated practices. The results of the trial were very encouraging and provided valuable information for the design of a community-wide intervention. Our findings help explain why the emphasis given in most sanitation projects, where efforts have been concentrated on the promotion of latrines, has failed to induce their utilization by small children. Sanitation projects should incorporate interventions that will promote hygienic defecation and stool clearance practices for infants and small children.

[Severe liver failure in erythropoietic protoporphyria. A report of a case treated by liver transplantation]

Severe liver failure is a rare complication of erythropoietic protoporphyria (PEP), which is associated with a high rate mortality. Until now, 31 patients with this hepatic complication had underwent a liver transplantation, with a high rate of survival, but their long-term outcome is not well established. We report the first case in Spain of PEP in 59-year-old, whose acute liver failure was treated with liver transplantation, without postoperative complications. The patient is in good clinical condition 30 months later. Nevertheless during the first eleven months of follow-up the plasma levels of protoporphyrin remained elevated, which was accompanied of biochemical and histological evidence of relapse of the metabolic disease in the graft. Cases such as this stress the usefulness of liver transplantation, but also the need of more efficient measures to decrease the protoporphyrin levels before and after the transplant, in order to prevent hepatic and extrahepatic complications in these patients.

[Effect of an algae extract and several plant growth regulators on the nutritional value of potato (Solanum tuberosum L. var. gigant)]

Four commercial plant-growth (Biofol, Biozyme, Cytokin and Activol) and an extract from algae (AlgaEnzims) were applied at commercial doses in potatoes (S. tuberosum L. var. gigant) with and objective to evaluate its effect on nutritional value (dry-matter, water content, ashes, fat, protein, carbohydrates and assimilable fiber). These parameters were analyzed according to the Official Methods of Analysis (AOAC). The experimental design was in Random Blocks with 8 treatments and 4 replications with 32 lots in total. The statistical analysis was after Random Blocks for all bromatological analyses. The treatment algae in soil gave the highest ash content (6.20). Algae in soil (9.30), algae on foliage (8.90) and Cytokin (8.70) gave the highest values in protein as compared with test (6.20). Carbohydrate content was highest in Biofol (88.21), assimilable fiber was higher in algae in soil and on foliage (5.84) and lowest with Biofol (1.67). Highest fat content in the tuber was obtained with Biozyme and Cytokin and highest protein content with AlgaEnzims. With Activol the highest tuber production is obtained.

[Virtual cystoscopy of bladder neoplasms. Preliminary experience]

PURPOSE

We investigated the comparative sensitivity of virtual and conventional cystoscopy in patients with urinary bladder cancer.

MATERIAL AND METHODS

Twelve patients (8 men and 4 women; mean age: 61 years, range: 49-73) with findings of bladder cancer at conventional cystoscopy were submitted to volumetric spiral CT of the urinary bladder. Before the examination, the urinary bladder was distended with 180-200 mL of air. CT findings were then sent to an independent workstation to generate interactive intraluminal views of the bladder. The findings of virtual cystoscopy were compared with those of conventional cystoscopy in 11 patients and with the findings of transurethral resection after urethrotomy in one patient. All lesions had pathologic confirmation.

RESULTS

Eighteen (90%) of 20 masses detected on conventional cystoscopy were visualized with virtual cystoscopy. The latter allowed readers to identify 13 of 13 masses (100%) > 1 cm and only 5 of 7 (71%) < 1 cm; three 4-mm masses were missed. Although only a subjective evaluation of lesion size was possible on conventional cystoscopy, there seemed to be good agreement on mass size and site with both techniques.

DISCUSSION

Cystoscopy plays a key role in the diagnosis of urinary bladder carcinoma. However cystoscopy is invasive, has a limited field of view and lacks an objective scale; moreover, it is not indicated in patients with severe urethral strictures or active vesical bleeding. In our study, virtual cystoscopy depicted all the masses > 1 cm, and a lesion in a diverticulum with a small opening. Virtual cystoscopy was also very useful in a patient with urethral stricture (who could no be submitted to conventional cystoscopy) where it showed the lesion before transurethral resection after urethrotomy. The virtual technique could also be complementary to conventional cystoscopy in evaluation of bladder base and anterior bladder neck, as well as for postchemotherapy follow-up. Unfortunately virtual cystoscopy does not allow biopsy of suspicious lesions.

TNF-alpha and IL-10 modulate the induction of apoptosis by virulent Mycobacterium tuberculosis in murine macrophages

The Bcg/Nramp1 gene controls early resistance and susceptibility of macrophages to mycobacterial infections. We previously reported that Mycobacterium tuberculosis-infected (Mtb) B10R (Bcgr) and B10S (Bcgs) macrophages differentially produce nitric oxide (NO-), leading to macrophage apoptosis. Since TNF-alpha and IL-10 have opposite effects on many macrophage functions, we determined the number of cells producing TNF-alpha and IL-10 in Mtb-infected or purified protein derivative-stimulated B10R and B10S macrophages lines, and Nramp1+/+ and Nramp1-/- peritoneal macrophages and correlated them with Mtb-mediated apoptosis. Mtb infection and purified protein derivative treatment induced more TNF-alpha+Nramp1+/+ and B10R, and more IL-10+Nramp1-/- and B10S cells. Treatment with mannosylated lipoarabinomannan, which rescues macrophages from Mtb-induced apoptosis, augmented the number of IL-10 B10R+ cells. Anti-TNF-alpha inhibited apoptosis, diminished NO- production, p53, and caspase 1 activation and increased Bcl-2 expression. In contrast, anti-IL-10 increased caspase 1 activation, p53 expression, and apoptosis, although there was no increment in NO- production. Murine rTNF-alpha induced apoptosis in noninfected B10R and B10S macrophages that was reversed by murine rIL-10 in a dose-dependent manner with concomitant inhibition of NO- production and caspase 1 activation. NO- and caspase 1 seem to be independently activated in that aminoguanidine did not affect caspase 1 activation and the inhibitor of caspase 1, Tyr-Val-Ala-Asp-acylooxymethylketone, did not block NO- production; however, both treatments inhibited apoptosis. These results show that Mtb activates TNF-alpha- and IL-10-dependent opposite signals in the induction of macrophage apoptosis and suggest that the TNF-alpha-IL-10 ratio is controlled by the Nramp1 background of resistance/susceptibility and may account for the balance between apoptosis and macrophage survival.

Detection of the 70-kilodalton histoplasma capsulatum antigen in serum of histoplasmosis patients: correlation between antigenemia and therapy during follow-up

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals, who may develop a progressive disseminated form which is often fatal if it is untreated. In such patients, the detection of antibody responses for both diagnosis and follow-up may be of limited use, whereas the detection of Histoplasma capsulatum var. capsulatum antigens may provide a more practical approach. We have recently described an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection in patients' sera of a 69- to 70-kDa H. capsulatum var. capsulatum-specific antigen which appears to be useful in diagnosis. To investigate its potential for the follow-up of histoplasmosis patients during treatment, antigen titers in the sera of 16 patients presenting with different clinical forms of histoplasmosis were monitored at regular intervals for up to 80 weeks. Sera from four of five patients with the acute form of the disease showed rapid falls in antigenemia, becoming antigen negative by week 14 (range, weeks 10 to 16). Sera from four patients with disseminated histoplasmosis showed falls in antigen levels; three of them became antigen negative by week 32; the fourth patient became negative by week 48. In contrast, antigen titers in four of six AIDS patients with the disseminated form of the disease remained positive throughout follow-up. Sera from only one patient who presented with the chronic form of the disease were analyzed, and this individual's serum became antigen negative by week 9. The inhibition ELISA is shown to be of particular use in the monitoring of non-AIDS patients with the acute and disseminated forms of the disease and may complement existing means of follow-up.

Impact of adduct determination on the assessment of cancer susceptibility

The characterization of genetic determinants for cancer susceptibility is important for understanding disease pathogenesis and for preventive measures. There is growing evidence that a group of predisposing polymorphic genes exists, such as those involved in carcinogen metabolism and repair, which may increase cancer in certain environmentally exposed subjects, even those exposed only to low levels of carcinogens. In developing preventive strategies, it is therefore necessary to identify these vulnerable members in our society, particularly those suffering from an unfortunate combination of high carcinogen exposure, cancer-predisposing genes and lack of protective (dietary) factors. Thus, molecular epidemiology faces the difficult task of analyzing carcinogen-exposed individuals for a combination of genotypes associated with cancer susceptibility. Once identified, combinations of cancer-predisposing genes can then be used as intermediate risk markers rather than taking cancer as an endpoint. In case-control studies, simultaneous measurements were carried out in each subject to determine exposure/early effect markers, e.g. polycyclic aromatic hydrocarbons (PAH)-DNA adducts, and susceptibility markers, e.g. genetic polymorphism, in drug-metabolizing enzymes related to cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase (GSTM1) genes. The genotype dependence of human lung (+)-anti-benzo[a]pyrene diol-epoxide (BPDE)-DNA adducts in lung cancer patients was examined. BPDE-DNA adduct levels in bronchial tissue of smokers with high pulmonary CYP1A1 inducibility (by immunohistochemistry) and GSTM1 inactive were approximately 100-fold higher than in subjects with an active GSTM1 at similar smoking dose. Further genetic analyses confirmed that the combination of CYP1A1 homozygous mutants and GSTM1 inactive leads to high levels of BPDE-DNA adducts in human lung of smokers and white blood cells of PAH-exposed coke oven workers. Thus, BPDE-DNA adduct levels resulting from the "at risk" genotype combinations may serve as markers to identify high-risk subjects among smokers and individuals occupationally and/or environmentally exposed to PAH.

The effect of parathion on mouse testicular and epididymal development cultured in chicken allantochorion

Parathion is a widely used organophosphoric pesticide which has also been reported to interfere with mouse spermatogenesis. Moreover it has been related to prenatal toxicity in mammals. Sixteen A/ Snell mice were sacrificed at day 17 of pregnancy. Testes and epididymides of the male fetuses were implanted in the allantochorion of chicken eggs. Three experimental conditions of the egg injections were considered: Group I: 1 ml of parathion (0.5 mg/ml), Group II: 1 ml of parathion (1 mg/ml), and Group III: 1 ml distilled water (control group). The implanted subjects continued their development for 4 days (i.e. to complete the gestational period for mice). The cell proliferation and differentiation of the epithelial cells of the epididymis were evaluated with the use of the monoclonal antiproliferating cell nuclear antigen (PCNA-cyclin) antibody, and the AE1 keratin complex antibody. Parathion altered the allantochorion, as 15% of the chicken embryos died in Group I and 40% in Group II, vs. only 8% in controls (Group III). However, no malformations were seen in the surviving embryos. In the testicular implants, the seminiferous cords of Group I had the same cytological characteristics of germ and pre-Sertoli cells as the control, except for involuting Leydig cells. Contrarily, in the cases with higher doses of parathion (Group II), there was a complete disorganisation of the seminiferous cords and the interstitium. In some testes, hyaline degeneration of the seminiferous cords was observed. No cell proliferation was evident, and the epididymal morphology was apparently unaffected. Therefore, parathion seems to interfere with normal testicular differentiation. However, in spite of interstitial damage, the epididymal development seems unaltered. Since the epididymis is an androgen-dependent organ, it may be postulated that testosterone production is still sufficient to support epididymal development but not spermatogenic cell line differentiation.

[Aneurysm of the iliac artery in an elderly subject. Role of treatment with covered endoprosthesis]

BACKGROUND

Coated stents can be an alternative to open surgery for arterial aneurysms, particularly in patients with high operative risk.

CASE REPORT

A 90-year-old man with advanced stage cardiopathy developed a 52 mm aneurysm of the iliac artery. Perioperative imaging (arteriography with marked catheter, CT-scan and endovascular ultrasonography) provided a precise description. The material used (PTFE coated thermal memory endoprosthesis, balloon in the hypogastric) provided effective exclusion.

DISCUSSION

Endovascular treatment can be a useful alternative to open surgery for arterial aneurysm in the very elderly.

[Pulmonary textiloma revealed by hemoptysis 12 years after thoracotomy]

INTRODUCTION

Pulmonary textiloma or retained surgical sponge is rare but can have detrimental consequences. Its diagnosis is difficult, even when using computerized tomography (CT) scan and is always a medical and legal problem.

EXEGESIS

We report the case of a 46-year-old man with a history of pulmonary tuberculosis diagnosed by thoracotomy in 1986, who was admitted to hospital for hemoptysis. CT scan showed the existence of a pulmonary lesion. Clinical, radiological and fiberoptic endoscopy features mimicked an abscess or bronchiectasis. The patient underwent left inferior lobectomy. Anatomical findings led to the diagnosis of textiloma.

CONCLUSION

This case shows the difficult in diagnosing pulmonary textiloma, even when using CT scan. Textiloma should be considered when an atypical pulmonary mass is found in a patient with past history of thoracotomy.

Antigenemia in patients with paracoccidioidomycosis: detection of the 87-kilodalton determinant during and after antifungal therapy

Serological diagnosis and follow-up of paracoccidioidomycosis (PCM) patients have relied mainly on the detection of antibody responses by using techniques such as complement fixation (CF) and immunodiffusion. We recently described a novel inhibition enzyme-linked immunosorbent assay (inh-ELISA) which proved to be useful in the diagnosis of PCM via the detection of an 87-kDa determinant in patient sera (B. L. Gomez, J. I. Figueroa, A. J. Hamilton, B. Ortiz, M. A. Robledo, R. J. Hay, and A. Restrepo, J. Clin. Microbiol. 35:3278-3283, 1997). This test has now been assessed as a means of following up PCM patients. A total of 24 PCM patients, classified according to their clinical presentation (6 with the acute form of the disease, of whom two had AIDS, 12 with the multifocal form of the disease, and 6 with the unifocal form of the disease), were studied. The four human immunodeficiency virus-negative patients with acute PCM showed a statistically significant decrease in circulating antigen levels after the start of antifungal therapy. Antigen levels in this group became negative by our criteria ( Collapse

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MESH Headings

• AIDS-Related Opportunistic Infections/diagnosis
• AIDS-Related Opportunistic Infections/drug therapy
• AIDS-Related Opportunistic Infections/microbiology
• Acute Disease
• Adolescent
• Adult
• Aged
• Antifungal Agents/therapeutic use
• Antigens, Fungal/blood
• Antigens, Fungal/chemistry
• Enzyme-Linked Immunosorbent Assay/methods
• Epitopes/blood
• Epitopes/chemistry
• Female
• Fungemia/diagnosis
• Fungemia/drug therapy
• Fungemia/microbiology
• Humans
• Male
• Middle Aged
• Molecular Weight
• Paracoccidioides/immunology
• Paracoccidioides/isolation & purification
• Paracoccidioidomycosis/diagnosis
• Paracoccidioidomycosis/drug therapy
• Paracoccidioidomycosis/microbiology
• Time Factors

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[Multi-plane transesophageal echocardiography in cardiac angiosarcoma. Apropos of a case]

The authors report the case of a right atrial angiosarcoma extending to the right ventricle, presenting with a massive pericardial effusion, in a 30 year old man. The patient underwent surgical ablation of the tumour with right atrial reconstruction, tricuspid valvuloplasty, plicature of the right ventricle and a right coronary artery bypass graft with complementary chemotherapy. This case illustrates the decisive contribution of multiplane transoesophageal echocardiography in the preoperative investigation, providing accurate information about the site and extension of the tumour, and even about the malignant character of the pathology. Magnetic resonance imaging, though useful, did not provide any further information in this case. Unfortunately, thoracic CT scan, performed 15 days after surgery, showed the presence of pulmonary metastases, confirming the very poor prognosis of these tumours.

Activation of B cells by 1 microm particulate lysozyme or peptides: a Th-dependent pathway requiring CD40-CD40 ligand interaction

Many antigens encountered by the immune system are included in complex structures such as bacteria or parasites. We previously developed an in vivo model to study the immunogenicity of particulate antigens, based on covalent linkage of proteins or peptides to 1 microm latex particles and showed that these antigens cannot be presented to MHC class II-restricted specific T cells by B cells. However, they induce strong CD4+ T cell responses when injected to mice without adjuvant. The present study demonstrates that four out of the five proteins tested did not stimulate antibody synthesis when linked to 1 microm microparticles, although a strong IgG production was induced by the same proteins administered in soluble form with adjuvant. In contrast, lysozyme and two synthetic peptides containing B and T cell viral epitopes induced strong and long-lasting specific antibody responses when linked to 1 micrometer synthetic beads. The isotypic pattern of antibodies induced by particulate lysozyme was similar to that induced by the soluble protein in alum. Studies using CD4+ T cell-depleted mice revealed that the induction of antibodies by particulate lysozyme strictly required Th cell activity. Moreover, the T-B cell cooperation involved in B cell activation by antigens linked to beads required CD40-CD40 ligand interaction. Thus, these particulate antigens provide a useful tool to study the mechanisms of induction of antibody response against complex bacterial or parasitic antigens. Moreover, they may represent attractive candidates to elaborate efficient new vaccines using short synthetic peptides.

Induction of apoptosis in murine macrophages by Mycobacterium tuberculosis is reactive oxygen intermediates-independent

Infection with Mycobacterium tuberculosis induces apoptosis in murine macrophage lines. Resistant macrophages B10R (Bcgr) are more prone to undergo apoptosis than susceptible B10S (Bcgs) macrophages. Apoptosis and inhibition of intracellular growth of the mycobacteria seem to be dependent on the production of nitric oxide, since both can be reverted by aminoguanidine (AMG). Although B10R macrophages produce more superoxide anion than B10S macrophages after infection with M. tuberculosis, reactive oxygen intermediate (ROIs) scavengers did not affect uptake of 3H-uracil incorporation by the mycobacteria nor the induction of apoptosis. These results further suggest that both phenomena are dependent on the production of nitric oxide by the infected macrophages.

Alcohol and drug use, and depression among Hispanic men in early adulthood

Community research and clinical practice have shown that alcohol and drug use and depression are interrelated. Among Hispanics, acculturation may play a role in these relationships. To investigate these relationships as well as alcohol-related problems, we interviewed 288 Puerto Rican, Dominican, and Colombian men in early adulthood. No significant differences emerged in the proportions of abstainers across the three groups. Colombians drank significantly more frequently and had more alcohol-related problems than Dominicans. Dominicans were at least risk for and least likely to have alcohol-related problems. Puerto Ricans were much more likely to use drugs than the other Hispanic men. Drug use was associated with an increased likelihood of heavy drinking which, in turn, increased the risk of drug use and depression. Acculturation decreased the risk of drug use. Results are discussed in terms of implications for community psychology research and interventions.