[New CT and MR imaging techniques in non-traumatic neurological emergencies]

New CT and MR imaging techniques used for non-traumatic neurologic emergencies (represented mostly by ischemic stroke) fulfil the exigency to know quickly and with high accuracy the presence of abnormalities in cerebral perfusion, with the final aim to practise immediately all the treatments needed to prevent the progression of the neurologic damage, by selecting those patients to undergo fibrinolysis, which is useless and not indicated in many occasions. The diagnosis of ischemia is only the first goal reached by these new diagostic tools, while it is nowdays possible and required to stratify the risk factors for the therapy and to accurate select those patients candidates to fibrolnilysis, in order to minimize the risck related to the inadequate treatment choice.

[Neuroimaging of Alzheimer disease: current role and future potential]

Alzheimer disease (AD), the most common cause of dementia in the elderly, is a progressive neurodegenerative disorder, associated with deterioration in cognition and behaviour. With the availability of newer drugs for symptoms treatments there is a general agreement to the need of an early diagnosis and an the development of new sensitive tools, to identify and/or monitor early cerebral changes, suggestive for AD. CT and MRI are recommended for routine evaluation, in order to exclude treatable causes of dementia and to exactly evaluate the degree of cerebral atrophy and the presence of parenchymal signal abnormalities. Functional imaging, including PET, SPECT and functional MR techniques, are able to investigate physiological cerebral function, such as blood perfusion, metabolism, activation, molecular composition and water diffusibility, and have the potential to detect subtle pathological changes earlier during course of disease. MRI can provide both an accurate morphological assessment and a functional evaluation. Further investigations are needed to precisely define which will be the role of the different MR techniques. Most likely an exhaustive evaluation of AD will include information obtained by conventional and functional imaging, combined with clinical, laboratory and genetic findings.

[Trihalomethanes in the drinking water of Carabobo State, Venezuela]

OBJECTIVE

Disinfection of water with chlorine in water treatment plants leads to the formation of trihalomethanes (THMs). These compounds are associated with adverse health effects. The aim of this study was to analyze THM concentrations in the water provided for human consumption in the two main water treatment systems of Carabobo State: the Alejo Zuloaga plant and the Pao-Cachinche reservoir, which form the Central Regional System I (CRS I), and the Lucio Baldo Soules plant and the Pao-La Balsa reservoir, which form the Central Regional System II (CRS II).

METHODS

We analyzed 144 water samples collected in 6 samplings carried out in 2000 and 2001. THM concentrations were determined by gas chromatography using the headspace technique. The concentrations of the following THMs were measured: chloroform (CHCl3), bromoform (CHBr3), chlorodibromomethane (CHBr2Cl) and bromodichloromethane (CHCl2Br).

RESULTS

The concentration of total THMs was between 47.84 g/l and 94.23 g/l. CHCl3 was the most commonly formed compound representing 83% of all THMs in the CRS I and 82% in the CRS II. The concentrations of total THMs in the CRS I, specifically in the Baja and San Diego networks, were significantly higher (p < 0.05) than permissible levels set by the American Environmental Protection Agency (80 g/l) for the sum of all four THMs.

CONCLUSIONS

The results show that in the area studied there is a risk of adverse health effects due to THMs in drinking water, especially in the Baja and San Diego networks.

B cell specificity contributes to the outcome of diabetes in nonobese diabetic mice

Type I diabetes mellitus (TIDM) is an autoimmune disorder characterized by T cell-mediated destruction of insulin-producing beta cells in the pancreas. In the nonobese diabetic (NOD) model of TIDM, insulitis and diabetes are dependent on the presence of B lymphocytes; however, the requirement for specificity within the B cell repertoire is not known. To determine the role of Ag-specific B cells in TIDM, V(H) genes with different potential for insulin binding were introduced into NOD as H chain transgenes. VH125 H chain combines with endogenous L chains to produce a repertoire in which 1-3% of mature B cells are insulin specific, and these mice develop accelerated diabetes. In contrast, NOD mice harboring a similar transgene, VH281, with limited insulin binding develop insulitis but are protected from TIDM. The data indicate that Ag-specific components in the B cell repertoire may alter the course of TIDM.

[Role of magnetic resonance in shoulder disease]

Next to the knee, the shoulder is the most common joint to be referred for MRI. Excellent soft tissue contrast and multiplanar acquisition provide optimal assessment of muscle, tendons, hyaline and fibrous cartilage, joint capsule, fat, bursae and bone marrow. In this article the most common indications for shoulder MRI are reviewed and discussed, but we focused primarily on the rotator cuff syndrome and shoulder instability. Correct diagnosis requires the use of appropriate pulse sequences and imaging planes, proper patient positioning, and a satisfactory surface coil. Moreover, technical improvements continuously augment the ability of MRI to study the shoulder; for example Magnetic Resonance arthrography is superior to the other imaging techniques in evaluation of glenohumeral joint. This interdependence between technical development in MRI and clinical advance in shoulder therapy ensures that MRI will continue to play an important role in the routine management of patients with shoulder disease.

Occupational exposure to airborne mercury during gold mining operations near El Callao, Venezuela

OBJECTIVE

The National Institute for Occupational Safety and Health (NIOSH) recently conducted a cross-sectional study during gold mining operations near El Callao, Venezuela. The purpose of the study was to assess mercury exposures and mercury-related microdamage to the kidneys. The study consisted of concurrent occupational hygiene and biological monitoring, and an examination of the processing techniques employed at the different mining facilities. Mercury was used in these facilities to remove gold by forming a mercury-gold amalgam. The gold was purified either by heating the amalgam in the open with a propane torch or by using a small retort.

METHODS

Thirty-eight workers participated in this study. Some participants were employed by a large mining company, while others were considered "informal miners" (self-employed). Mercury exposure was monitored by sampling air from the workers' breathing zones. These full-shift air samples were used to calculate time-weighted average (TWA) mercury exposure concentrations. A questionnaire was administered and a spot urine sample was collected. Each urine sample was analyzed for mercury, creatinine, and N-acetyl-beta-D-glucosaminidase (NAG).

RESULTS

The range for the 8-h TWA airborne mercury exposure concentrations was 0.1 to 6,315 micrograms/m3, with a mean of 183 micrograms/m3. Twenty percent of the TWA airborne mercury exposure measurements were above the NIOSH recommended exposure limit (REL) of 50 micrograms/m3, and 26% exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 25 micrograms/m3. The mean urine mercury concentration was 101 micrograms/g creatinine (microgram/g-Cr), and the data ranged from 2.5 to 912 micrograms/g-Cr. Forty-two percent of the study participants had urine mercury concentrations that exceeded the ACGIH biological exposure index (BEI) of 35 micrograms/g-Cr. Urinary NAG excretion is considered a biological marker of preclinical, nonspecific microdamage to the kidney's proximal tubule cells. The mean urine NAG concentration was 3.6 International Units/g-Cr (IU/g-Cr) with a range of 0.5 to 11.5 IU/g-Cr. Three workers had urine NAG levels in excess of the reference values. Correlation analyses found statistically significant correlations between airborne mercury exposure and urine mercury level (P = 0.01), and between urine mercury level and urine NAG excretion (P = 0.01). In addition, the airborne mercury exposure data and urine mercury data were segregated by job tasks. A Wilcoxon rank sum test revealed significant correlations between tasks and mercury exposure (P = 0.03), and between tasks and urine mercury level (P = 0.02).

CONCLUSIONS

The tasks with the highest mean airborne mercury exposures were "burning the mercury-gold amalgam" and "gold refining/smelting". Recommendations were provided for improving the retort design to better contain mercury, for ventilation in the gold shops, and for medical surveillance and educational programs.

[Central nervous system malformations in a Clinical Hospital of Universidad de Chile and in Chilean maternity hospitals that participated in the Latin American Collaborative Study of Congenital Malformations (ECLAMC)]

BACKGROUND

In Chile, the rates of central nervous system congenital malformations at birth remain high, when compared with the rest of the world.

AIM

To report the rates of central nervous system congenital malformations in Chilean hospitals.

MATERIAL AND METHODS

Using the ECLAMC protocol, every malformed newborn or stillbirth, weighing more than 500 g at birth is registered using a standard protocol, and the next non malformed child of the same sex born in the same hospital is assigned as control.

RESULTS

The rates of central nervous system congenital malformations are higher at the University of Chile Clinical Hospital than in the rest of Chilean hospitals or Latin American Hospitals. There are significantly higher rates of anencephalia in Concepcion and spina bifida in Valdivia, Rancagua and Concepcion. In the University of Chile Clinical Hospital, global annual rates have a negative slope of -0.0259 per 1000 born alive, with a correlation coefficient of -0.125 (p < 0.05). The slope is positive among children born alive, with an annual rate increase of 0.071. Among stillbirths, the slope is -0.47 per 1000 born alive. Sixty two percent of malformed children were female. Among children with neural tube defects, 30% had a malformed relative and, of these, 66% had the same malformation.

CONCLUSIONS

Family clustering of neural tube defects, supports the influence of a genetic factor influencing their appearance.

Myeloperoxidase--463A variant reduces benzo[a]pyrene diol epoxide DNA adducts in skin of coal tar treated patients

The skin of atopic dermatitis patients provides an excellent model to study the role of inflammation in benzo[a]pyrene (BaP) activation, since these individuals are often topically treated with ointments containing high concentrations of BaP. In this study we have determined, by HPLC with fluorescence detection, the BaP diol epoxide (BPDE)-DNA adduct levels in human skin after topical treatment with coal tar and their modulation by the -463G-->A myeloperoxidase (MPO) polymorphism, which reduces MPO mRNA expression. BPDE-DNA adduct levels were 2.2 and 14.2 adducts/10(8) nt for MPO-463AA/AG and -463GG, respectively. The predominant BaP tetrol observed was tetrol I-1, which is derived after hydrolysis of the anti-BPDE-DNA adduct. The tetrol I-1/II-2 ratio, corresponding to the anti/syn ratio, was 6.7. The (32)P-post-labeling assay was also performed and thin layer chromatograms showed a major spot with a chromatographic location corresponding to BPDE-DNA. The mean values of the BPDE-DNA adduct spots were 3.8 +/- 2.4 per 10(8) nt for MPO-463AA/AG (n = 3) and 18.4 +/- 11.0 per 10(8) nt for MPO-463GG (n = 7), respectively (P = 0.03). One individual with the homozygous mutant genotype (-463AA) even had a 13-fold lower adduct level (1.4 per 10(8) nt) as compared to MPO-463GG subjects. In conclusion, these data show for the first time: (i) the in vivo formation of BPDE-DNA adducts in human skin treated with coal tar; (ii) that the MPO-463AA/AG genotype reduced BPDE-DNA adduct levels in human skin.

[Evaluation of exposure to carbon monoxide among kiosk vendors. Valencia, Venezuela]

OBJECTIVE

To study the level of exposure to carbon monoxide (CO), factors contributing to this exposure, and the exposure's potential effects on the health of vendors who have kiosks located on an avenue with heavy vehicular traffic in the city of Valencia, Venezuela.

METHODS

We measured the concentration of CO in the air (CO-air) in 16 kiosks in Valencia and also determined the concentration of carboxyhemoglobin (COHb) in the blood of 20 individuals who worked in those kiosks. We also determined the COHb concentrations in a control group made up of 23 professors, students, and workers from Simón Rodríguez University, which is in a town some 120 km from Valencia, in a remote mountainous area without noticeable pollution.

RESULTS

In seven of the Valencia kiosks (43.7%) the permissible CO-air limits were exceeded. Among the vendors experimental group there was no correlation between the concentrations of CO-air and of COHb. The COHb average for the experimental group (2.9%) was significantly higher than that of the control group (1.6%) and that of the permissible level, according to the analytical method used (< 1.5%). Of a group of symptoms possibly related to CO exposure that were assessed as to whether or not they occurred on a daily basis, all of these symptoms affected a larger percentage of individuals in the experimental group than in the control group. The most common of these symptoms among the experimental group were fatigue and strong headaches.

CONCLUSIONS

While the vendors' COHb average does not seem alarming, the CO exposures found could have an adverse impact on these workers' health, especially if they suffered from cardiovascular disorders, or as the result of additive interactions with other environmental pollutants. We recommend carrying out additional studies with more frequent and extended measurements of air quality, to produce information that could be applied in efforts to prevent and control adverse CO health effects.

Anergy and not clonal ignorance determines the fate of B cells that recognize a physiological autoantigen

Autoantibodies to insulin arise spontaneously in the insulin autoimmune syndrome and in type I diabetes. In addition, administration of insulin to individuals without autoimmune disease routinely results in Abs that bind autologous hormone. These observations and findings in transgenic models of tolerance led to an inference that physiological levels of hormones and growth factors, such as insulin, are not sufficient to induce tolerance in B cells, a state termed clonal ignorance. In contrast, we have discovered that virtually all conventional B cells expressing a low affinity anti-insulin transgene interact with endogenous insulin and are effectively silenced for Ig production and for T cell-dependent immune responses. A fraction of transgenic B cells escapes silencing and functions autonomously to produce insulin Abs that may lower fasting blood sugars similar to an insulin autoimmune syndrome. These B cells have characteristics of a B1-like subset and are depleted by hypotonic peritoneal lysis. These findings question the concept of clonal ignorance and show that physiological concentrations of Ag may effectively silence conventional B cells even when the affinity for autoantigen is low. Self-reactivity may arise in the repertoire because of compartmental differences that govern the fate of B cells and not as a result of true clonal ignorance.

Assessing mercury health effects in gold workers near El Callao, Venezuela

Mercury exposure and health status were examined in 40 gold workers in the area surrounding El Callao, Venezuela. Concentrations of mercury in workplace air were measured on 3 successive days, and spot urine and hair samples were also taken for analysis. Subjects underwent a physical examination and completed a questionnaire regarding employment history, work activities involving mercury exposure, use of protective clothing and equipment, and frequency of 37 symptoms associated with mercury toxicity. A complete set of health data was collected for 29 of the subjects. Use of protective equipment was limited, and 17.9%, 24.1%, and 48.3% of subjects had mercury concentrations in air, hair, and urine, respectively, above contemporary occupational exposure guidelines. Physical examination found the workers to be generally healthy and without overt symptoms of mercury toxicity. The frequency of psychoneurological, gastrointestinal, cardio-respiratory, and dermal symptoms was unrelated to any of the measures of mercury exposure. Two subjects had modestly elevated urinary levels of N-acetyl beta-D-glucosaminidase. Despite substantial occupational exposure to mercury among a number of the subjects, few adverse health effects were observed that were plausibly related to mercury.

[Disabling malformations in Chile. Latin American Cooperative Study of Congenital Malformations (ECLAMC), 1982-1997]

BACKGROUND

The ECLAMC (Estudio Colaborativo Latinoamericano de Malformaciones Congénitas) is an epidemiological surveillance program for congenital defects that operates in Chile since 1969.

AIM

To communicate the frequency of disabling congenital defects in Chile in the period 1982-1997.

MATERIAL AND METHODS

A review of the ECLAMC registry, choosing 12 congenital defects: amelia, limb amputations, limb reductions, arthrogryposis, hip luxation and subluxation, spina bifida, hydrocephaly, microcephaly, cephalocele, talipes equinovarus, Down syndrome and multiple abnormalities.

RESULTS

In the study period, 283,403 births occurred and 7,917 newborns were malformed (7,654 born alive and 263 stillbirths). The congenital defects prevalence rates appeared higher in Chile than in other Latin American countries, specially among stillbirths. Among the studied maternity hospitals, the Clinical Hospital of the University of Chile, showed the higher prevalence of congenital defects. Rancagua and the Navy Hospital in Valparaiso have a high frequency of Down syndrome. Global rates in Chile and in the rest of ECLAMC for specific defects, do not have significant differences, except for hip subluxation, that has a lower incidence in Chile.

CONCLUSIONS

The ECLAMC allows to have a good knowledge of the prevalence of congenital malformations in Latin America.

Antigenicity and immunogenicity of the HIV-1 gp41 epitope ELDKWA inserted into permissive sites of the MalE protein

The highly conserved amino acid sequence ELDKWA of HIV-1 gp41 has been inserted into Escherichia coli MalE protein which had been shown to be an adequate carrier to present foreign epitopes to the immune system. We first investigated whether eight different permissive sites of MalE are able to tolerate an insertion of 7-50 residues encoding this epitope. Secondly, antigenicity of the epitope inserted in MalE protein was estimated from monoclonal antibody 2F5 binding analysis using the BIAcore(R) technology and its immunogenicity in mice was measured as the ability of hybrid proteins to elicit antibodies against a synthetic peptide containing this epitope. This study revealed a good correlation between the antigenicity of the inserted epitope and its immunogenicity. Increasing the length of the inserted epitope, as well as inserting multicopies of this epitope increased both its antigenicity and immunogenicity. However, none of the MalE hybrid proteins tested induced anti-HIV-1 neutralizing antibodies. This study strongly suggests that the capacity of the 2F5 epitope to induce neutralizing antibodies depends on the molecular context in which it is presented.

T-Cell receptor Vbeta repertoire CDR3 length diversity differs within CD45RA and CD45RO T-cell subsets in healthy and human immunodeficiency virus-infected children

The T-cell receptor (TCR) CDR3 length heterogeneity is formed during recombination of individual Vbeta gene families. We hypothesized that CDR3 length diversity could be used to assess the fundamental differences within the TCR repertoire of CD45RA and CD45RO T-cell subpopulations. By using PCR-based spectratyping, nested primers for all 24 human Vbeta families were developed to amplify CDR3 lengths in immunomagnetically selected CD45RA and CD45RO subsets within both CD4(+) and CD8(+) T-cell populations. Umbilical cord blood mononuclear cells or peripheral blood mononuclear cells obtained from healthy newborns, infants, and children, as well as human immunodeficiency virus (HIV)-infected children, were analyzed. All T-cell subsets from newborn and healthy children demonstrated a Gaussian distribution of CDR3 lengths in separated T-cell subsets. In contrast, HIV-infected children had a high proportion of predominant CDR3 lengths within both CD45RA and CD45RO T-cell subpopulations, most commonly in CD8(+) CD45RO T cells. Sharp differences in clonal dominance and size distributions were observed when cells were separated into CD45RA or CD45RO subpopulations. These differences were not apparent in unfractionated CD4(+) or CD8(+) T cells from HIV-infected subjects. Sequence analysis of predominant CDR3 lengths revealed oligoclonal expansion within individual Vbeta families. Analysis of the CDR3 length diversity within CD45RA and CD45RO T cells provides a more accurate measure of disturbances in the TCR repertoire than analysis of unfractionated CD4 and CD8 T cells.

[Occupational exposure and health effects of metallic mercury among dentists and dental assistants: a preliminary study. Valencia, Venezuela; 1998]

The aim of this investigation was to establish mercury (Hg) health effects on dentists and dental assistants, its relationship with exposure conditions and the potential renal damage Hg-related. The total population was 66 people, with a sample of 37 (56%), 22 dentists (59.5%, 19 male, 3 female) and 15 dental assistants (40.5%, all female). This was accomplished by an interview, Hg in urine (Hg-U) and N-acetyl-B-D-glucosaminidase activity in urine (NAG-U). Average values of Hg-U for dentists were 22.4 +/- 6.4 micrograms/g creatinine and 22.2 +/- 6.1 micrograms/g creatinine for dental assistants NAG-U average values were 2.9 +/- 3 U/L and 5.2 +/- 8.1 U/L respectively. There were no statistically significant differences between these averages (p > 0.05). There was no correlation between the quantity of amalgam prepared and working hours with Hg-U and NAG-U. Most frequent symptoms referred by dentists were: irritability (54.5%), cephalalgia (45.4%), arthralgias (40.9%), and the ones more referred by assistants were arthralgias (53.3%), irritability (46.7%) and cephalalgia (46.7%). It was not found a significative risk of having them among these groups. There is a need for further investigations including environmental monitoring of Hg, clinical evaluation and neurobehavioural tests to detect early effects. It is important to enforce personal safety measures to control the exposure.

The use of quality indicators for assessing radical prostatectomy specimens

The information contained in pathology reports of radical prostatectomy specimens is critically important to treating physicians for selecting adjuvant therapy, evaluating therapy, estimating prognosis, and analyzing outcomes. This information is also of importance to patients and their families. In recent years, the Cancer Committee of the College of American Pathologists and the Association of Directors of Anatomic and Surgical Pathology developed suggested protocols for reporting the findings on radical prostatectomy specimens. The objectives of this study were to assess radical prostatectomy-specimen reports by using quality indicators derived from existing suggested protocols and to thereby assist pathologists in improving the quality of their reports on such specimens. A retrospective chart review of 554 cases for the second 6-month period of 1996 focused on 10 quality indicators: submission of a frozen section; location of the adenocarcinoma; proportion of the specimen involved by adenocarcinoma; perineural involvement; vascular involvement; seminal vesicle involvement; periprostatic fat status; number of nodes submitted; status of nodes; and prostate intraepithelial neoplasia (PIN). The findings of this study were shared with the pathology departments in all hospitals in New York State. In addition, the 113 hospitals from which the 554 cases were drawn were given their institution-specific data. Teleconferences were held with the 37 hospitals that accounted for 72.4% of all cases. These conferences included directors of pathology and laboratories and focused on the aggregate statewide findings. The presence of quality indicators in reports varied from a mean of 14.8% (periprostatic fat) to a mean of 85.9% (seminal vesicle involvement). For all hospitals, 4 indicators (proportion of the specimen involved by adenocarcinoma, vascular involvement, periprostatic fat status, and PIN) were included in fewer than 50% of cases. These 4 quality indicators and an additional 3 others (submission of a frozen section, perineural involvement, and the number of nodes submitted) were included in fewer than 70% of cases. Only 3 indicators (location of the adenocarcinoma, seminal vesicle involvement, and the status of nodes) were found in more than 70% of cases. Although the mean level of quality indicator inclusion ranged from 14.8% to 85.9% for all cases examined, the absolute range for any individual indicator was 0% to 100%. Thus, some hospitals included a given indicator 100% of the time; others never included it. This pattern held true for all 10 indicators. High-volume hospitals (10 or more cases) performed significantly better than low-volume hospitals (1-4 cases) on 5 indicators (P < .05), and better, but not significantly so, for an additional 2 indicators. Overall, the mean inclusion levels for all 10 indicators were 10% higher for high-volume hospitals compared with low-volume and medium-volume hospitals (5-9 cases). This study demonstrated wide variations in the inclusion of quality indicators by pathologists in their radical prostatectomy-pathology reports. Whereas some hospitals always include given indicators, others never mentioned them. These marked disparities point to the need for standardized reporting for radical prostatectomy specimens.

In vivo induction of a high-avidity, high-frequency cytotoxic T-lymphocyte response is associated with antiviral protective immunity

Many approaches are currently being developed to deliver exogenous antigen into the major histocompatibility complex class I-restricted antigen pathway, leading to in vivo priming of CD8(+) cytotoxic T cells. One attractive possibility consists of targeting the antigen to phagocytic or macropinocytic antigen-presenting cells. In this study, we demonstrate that strong CD8(+) class I-restricted cytotoxic responses are induced upon intraperitoneal immunization of mice with different peptides, characterized as CD8(+) T-cell epitopes, bound to 1-microm synthetic latex microspheres and injected in the absence of adjuvant. The cytotoxic response induced against a lymphocytic choriomeningitis virus (LCMV) peptide linked to these microspheres was compared to the cytotoxic T-lymphocyte (CTL) response obtained upon immunization with the nonreplicative porcine parvovirus-like particles (PPV:VLP) carrying the same peptide (PPV:VLP-LCMV) previously described (C. Sedlik, M. F. Saron, J. Sarraseca, I. Casal, and C. Leclerc, Proc. Natl. Acad. Sci. USA 94:7503-7508, 1997). We show that the induction of specific CTL activity by peptides bound to microspheres requires CD4(+) T-cell help in contrast to the CTL response obtained with the peptide delivered by viral pseudoparticles. Furthermore, PPV:VLP are 100-fold more efficient than microspheres in generating a strong CTL response characterized by a high frequency of specific T cells of high avidity. Moreover, PPV:VLP-LCMV are able to protect mice against a lethal LCMV challenge whereas microspheres carrying the LCMV epitope fail to confer such protection. This study demonstrates the crucial involvement of the frequency and avidity of CTLs in conferring antiviral protective immunity and highlights the importance of considering these parameters when developing new vaccine strategies.

Mannosylated lipoarabinomannan antagonizes Mycobacterium tuberculosis-induced macrophage apoptosis by altering Ca+2-dependent cell signaling

Mycobacterium tuberculosis-induced macrophage apoptosis can be inhibited by mannosylated lipoarabinomannan (ManLAM), although it induces tumor necrosis factor (TNF)-alpha and NO production, which participate in apoptosis induction. ManLAM also modulates Ca(+2)-dependent intracellular events, and Ca(+2) participates in apoptosis in different systems. Ca(+2) was assessed for involvement in M. tuberculosis-induced macrophage apoptosis and for modulation by ManLAM. The role of Ca(+2) was supported by the blockade of apoptosis by cAMP inhibitors and the Ca(+2) chelator, BAPTA/AM. These agents also inhibited caspase-1 activation and cAMP-responsive element-binding protein translocation without affecting TNF-alpha production. Infection of macrophages with M. tuberculosis induced an influx of Ca(+2) that was prevented by ManLAM. Similarly, M. tuberculosis infection-altered mitochondrial permeability transition was prevented by ManLAM and BAPTA/AM. Finally, ManLAM and BAPTA/AM reversed the effects of M. tuberculosis on p53 and Bcl-2 expression. ManLAM counteracts the alterations of calcium-dependent intracellular events that occur during M. tuberculosis-induced macrophage apoptosis.

Cytokeratin, vimentin and E-cadherin immunodetection in the embryonic palate in two strains of mice with different susceptibility to glucocorticoid-induced clefting

An immunohistochemical study analyzing the pattern of distribution of some intermediate filament proteins, keratin and vimentin and, one adhesion molecule, cadherin in different stages of developing secondary palate in two strains of mice with different H-2 backgrounds was undertaken to investigate differences between a strain that is susceptible to glucocorticoid-induced cleft palate (A/Sn) and one that is resistant to glucocorticoid-induced cleft palate (C57/BL). The heads of embryos were processed by standard immunohistochemistry with antipancytokeratin (KAE1), antikeratins 18 (K18) and 19 (K19), antivimentin, and anti E-cadherin antibodies. Immunostaining with KAE1 antibody showed differences between the strains. The reaction was stronger in the medial edge epithelia of palatal processes in the A/Sn strain at all stages of palatogenesis. The C57/BL strain showed a weak immunostain to KAE1. Antivimentin antibody stained the mesenchymal cells of palatal processes and K18 and K19 showed no reaction in either strain of mice. Anti E-cadherin antibody was detected in the medial palatal epithelium of both strains of mice and in all stages of palate development. No differences were observed in E-cadherin and vimentin immunostain in palatal epithelium between the strains. The different expression of some cytokeratins in the embryonic palatal epithelium suggests that these intermediate filament proteins may be involved in different susceptibility to glucocorticoid-induced cleft palate in the mouse. The decreased immunoreaction of cytokeratins observed in the resistant strain would facilitate the disappearance of this molecule during the transformation from an epithelial to a mesenchymal phenotype that takes place during the development of the palate. These results may be related to the loss of cytokeratin expression observed during epithelial-mesenchymal transformation in the embryonic palate.