Behavioral changes in Japanese quails exposed to predicted environmentally relevant abamectin concentrations

Abamectin (ABA) toxicity in fish, amphibian and mammals was already proven, but its effect on birds is almost unknown. Thus, the aim of our study is to assess the impact of exposure to water with ABA for 40 days at predicted environmentally relevant concentrations on the behavior of female Japanese quails (Coturnix coturnix japonica). The three following experimental groups (n = 10 each) were set: "control", quails exposed to drinking water, without ABA, "EC1x" and "EC1000x" (0.31 mg a.i./L and 310.0 a.i./L, respectively; via commercial formulation Kraft® 36EC). The open field test showed anxiolytic response in birds exposed to ABA. These birds did not show locomotor changes or aggressive behavior in the aggressiveness test. Quails exposed to the pesticide did not react to the introduction of an object in the experimental box during the object recognition test, and it suggested perception deficit due to ABA. Moreover, these birds did not recognize the cat (Felix catus) and the vocalization of a hawk (Rupornis magnirostris) as potential predatory threats. These responses also suggest anti-predatory behavior deficit due to the pesticide. Thus, our study is pioneer in showing that water with ABA, at tested concentrations, influences the behavior of C. coturnix japonica, as well as in highlighting the potential impacts of this pesticide on this group of birds.

Metabotropic glutamate receptor 5 positive allosteric modulators are neuroprotective in a mouse model of Huntington's disease

Background and Purpose

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion in the huntingtin protein. We have previously demonstrated that the cell signalling of the metabotropic glutamate receptor 5 (mGluR5) is altered in a mouse model of HD. Although mGluR5-dependent protective pathways are more activated in HD neurons, intracellular Ca²⁺ release is also more pronounced, which could contribute to excitotoxicity. In the present study, we aim to investigate whether mGluR5 positive allosteric modulators (PAMs) could activate protective pathways without triggering high levels of Ca²⁺ release and be neuroprotective in HD.

Experimental Approach

We performed a neuronal cell death assay to determine which drugs are neuroprotective, Western blot and Ca²⁺ release experiments to investigate the molecular mechanisms involved in this neuroprotection, and object recognition task to determine whether the tested drugs could ameliorate HD memory deficit.

Key Results

We find that mGluR5 PAMs can protect striatal neurons from the excitotoxic neuronal cell death promoted by elevated concentrations of glutamate and NMDA. mGluR5 PAMs are capable of activating Akt without triggering increased intracellular Ca²⁺ concentration ([Ca²⁺]_i); and Akt blockage leads to loss of PAM-mediated neuroprotection. Importantly, PAMs' potential as drugs that may be used to treat neurodegenerative diseases is highlighted by the neuroprotection exerted by mGluR5 PAMs on striatal neurons from a mouse model of HD, BACHD. Moreover, mGluR5 PAMs can activate neuroprotective pathways more robustly in BACHD mice and ameliorate HD memory deficit.

Conclusions and Implications

mGluR5 PAMs are potential drugs that may be used to treat neurodegenerative diseases, especially HD.

The mGluR5 positive allosteric modulator, CDPPB, ameliorates pathology and phenotypic signs of a mouse model of Huntington's disease

Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by a polyglutamine expansion in the amino-terminal region of the huntingtin protein (htt), leading to motor dysfunction, cognitive decline, psychiatric alterations, and death. The metabotropic glutamate receptor 5 (mGluR5) has been implicated in HD and we have recently demonstrated that mGluR5 positive allosteric modulators (PAMs) are neuroprotective in vitro. In the present study we demonstrate that the mGluR5 PAM, CDPPB, is a potent neuroprotective drug, in vitro and in vivo, capable of delaying HD-related symptoms. The HD mouse model, BACHD, exhibits many HD features, including neuronal cell loss, htt aggregates, motor incoordination and memory impairment. However, chronic treatment of BACHD mice with CDPPB 1.5 mg/kg s.c. for 18 weeks increased the activation of cell signaling pathways important for neuronal survival, including increased AKT and ERK1/2 phosphorylation and augmented the BDNF mRNA expression. CDPPB chronic treatment was also able to prevent the neuronal cell loss that takes place in the striatum of BACHD mice and decrease htt aggregate formation. Moreover, CDPPB chronic treatment was efficient to partially ameliorate motor incoordination and to rescue the memory deficit exhibited by BACHD mice. Importantly, no toxic effects or stereotypical behavior were observed upon CDPPB chronic treatment. Thus, CDPPB is a potential drug to treat HD, preventing neuronal cell loss and htt aggregate formation and delaying HD symptoms.

Susceptibility-weighted imaging for the evaluation of patients with familial cerebral cavernous malformations: a comparison with t2-weighted fast spin-echo and gradient-echo sequences

BACKGROUND AND PURPOSE

The T2-weighted gradient-echo (GRE) imaging is currently the gold standard MR imaging sequence for the evaluation of patients with cerebral cavernous malformation (CCM) lesions. We aimed to compare the sensitivity of susceptibility-weighted imaging (SWI) with T2-weighted fast spin-echo (FSE) and GRE imaging in assigning the number of CCM lesions in patients with the familial form of the disease.

MATERIALS AND METHODS

We studied 15 patients (8 men, 7 women; mean age, 34 years) with familial CCM. All patients underwent MR imaging with the following sequences: T1-weighted spin echo, T2-weighted FSE, T2-weighted GRE, and SWI. Two neuroradiologists read the images regarding the number of lesions seen on each sequence. The final decisions were reached by consensus. The number of lesions on the different sequences was compared with analysis of variance, followed by a nonparametric Wilcoxon matched-pairs signed rank test.

RESULTS

The number of lesions was higher on T2-weighted GRE than on T2-weighted FSE (P = .001). In addition, more lesions were seen on SWI than on T2-weighted GRE (P = .001) and FSE (P = .001) sequences.

CONCLUSION

The sensitivity of SWI in assigning the number of CCM lesions in patients with the familial form of the disease is significantly higher than that of T2-weighted FSE and GRE sequences.

Effects of mercury intoxication on the response of horizontal cells of the retina of thraira fish (Hoplias malabaricus)

Methyl mercury (MeHg) is highly neurotoxic, affecting visual function in addition to other central nervous system functions. The effect of mercury intoxication on the amplitude of horizontal cell responses to light was studied in the retina of the fish Hoplias malabaricus. Intracellular responses were recorded from horizontal cells of fish previously intoxicated with MeHg by intraperitoneal injection (IP group) or by trophic exposure (T group). Only one retina per fish was used. The doses of MeHg chloride administered to the IP group were 0.01, 0.05, 0.1, 1.0, 2.0, and 6.0 mg/kg. The amplitudes of the horizontal cell responses were lower than control in individuals exposed to 0.01 (N = 4 retinas), 0.05 (N = 2 retinas) and 0.1 mg/kg (N = 1 retina), whereas no responses were recorded in the 1.0, 2.0, and 6.0 mg/kg groups. T group individuals were fed young specimens of Astyanax sp previously injected with MeHg corresponding to 0.75 (N = 1 retina), 0.075 (N = 8 retinas) or 0.0075 (N = 4 retinas) mg/kg fish body weight. After 14 doses, one every 5 days, the amplitude of the horizontal cell response was higher than control in individuals exposed to 0.075 and 0.0075 mg/kg, and lower in individuals exposed to 0.75 mg/kg. We conclude that intoxication with MeHg affects the electrophysiological response of the horizontal cells in the retina, either reducing or increasing its amplitude compared to control, and that these effects are related to the dose and/or to the mode of administration.

Colour vision and contrast sensitivity losses of mercury intoxicated industry workers in Brazil

We evaluated vision loss in workers from fluorescent lamp industries (n=39) who had retired due to intoxication with mercury vapour and had been away from the work situation for several years (mean=6.32 years). An age-matched control group was submitted to the same tests for comparison. The luminance contrast sensitivity (CSF) was measured psychophysically and with the sweep visual evoked potential (sVEP) method. Chromatic red-green and blue-yellow CSFs were measured psychophysically. Colour discrimination was assessed with the Farnsworth-Munsell 100-hue test, Lanthony D-15d test and Cambridge Colour Vision Test. Patient data showed significantly lower scores in all colour tests compared to controls (p<.001). The behavioural luminance CSF of the patients was lower than that of controls (p<.001 at all frequencies tested). This result was confirmed by the electrophysiologically measured sweep VEP luminance CSF except at the highest frequencies-a difference that might be related to stimulus differences in the two situations. Chromatic CSFs were also statistically significantly lower for the patients than for the controls, for both chromatic equiluminant stimuli: red-green (p<.005) and blue-yellow (p<.04 for all frequencies, except 2 cycles per degree (cpd), the highest spatial frequency tested) spatial gratings. We conclude that exposure to elemental mercury vapour is associated with profound and lasting losses in achromatic and chromatic visual functions, affecting the magno-, parvo- and koniocellular visual pathways.

Raman spectra of deuteriated taurine single crystals

The polarized Raman spectra of partially deuteriated taurine [(ND3+)0.65(NH3+)0.35(CH2)2SO3-] crystals from x(zz)x and x(zy)x scattering geometries of the Ag and Bg irreducible representations of the factor group C2h are reported. The temperature-dependent Raman spectra of partially deuteriated taurine do not reveal any evidence of the structural phase transition undergone by normal taurine at about 250 K, but an anomaly observed in the 180 cm-1 band at approximately 120 K implies a different dynamic for this band (which is involved in a pressure-induced phase transition) in the deuteriated crystal.

Contrast sensitivity threshold measured by sweep-visual evoked potential in term and preterm infants at 3 and 10 months of age

Although healthy preterm infants frequently seem to be more attentive to visual stimuli and to fix on them longer than full-term infants, no difference in visual acuity has been reported compared to term infants. We evaluated the contrast sensitivity (CS) function of term (N = 5) and healthy preterm (N = 11) infants at 3 and 10 months of life using sweep-visual evoked potentials. Two spatial frequencies were studied: low (0.2 cycles per degrees, cpd) and medium (4.0 cpd). The mean contrast sensitivity (expressed in percentage of contrast) of the preterm infants at 3 months was 55.4 for the low spatial frequency (0.2 cpd) and 43.4 for the medium spatial frequency (4.0 cpd). At 10 months the low spatial CS was 52.7 and the medium spatial CS was 9.9. The results for the term infants at 3 months were 55.1 for the low spatial frequency and 34.5 for the medium spatial frequency. At 10 months the equivalent values were 54.3 and 14.4, respectively. No difference was found using the Mann-Whitney rank sum T-test between term and preterm infants for the low frequency at 3 or 10 months or for the medium spatial frequency at 3 or 10 months. The development of CS for the medium spatial frequency was equally fast for term and preterm infants. As also observed for visual acuity, CS was equivalent among term and preterm infants, suggesting that visual experience does not modify the development of the primary visual pathway. An earlier development of synapses in higher cortical visual areas of preterm infants could explain the better use of visual information observed behaviorally in these infants.

Tetrachromatic input to turtle horizontal cells

Recent physiological experiments support behavioral and morphological evidence for a fourth type of cone in the turtle retina, maximally sensitive in the ultraviolet (UV). This cone type has not yet been included in the models proposed for connectivity between cones and horizontal cells. In this study, we examined the inputs of UV, S, M, and L cones to horizontal cells. We used the high-resolution Dynamic Constant Response Method to measure the spectral sensitivity of horizontal cells without background light and after adaptation to UV, blue (B), green (G), and red (R) light. We concluded the following: (1) Tetrachromatic input to a Y/B horizontal cell was identified. The spectral-sensitivity curves of the cell in three of the adaptation conditions were well represented by L-, M-, and S-cone functions. Adaptation to blue light revealed a peak at 372 nm, the same wavelength location as that determined behaviorally in the turtle. A porphyropsin template could be closely fitted to the sensitivity band in that region, strong evidence for input from a UV cone. (2) The spectral-sensitivity functions of R/G horizontal cells were well represented by the L- and M-cone functions. There was no indication of UV- or S-cone inputs into these cells. (3) The spectral sensitivities of the monophasic horizontal cells were dominated by the L cone. However, the shape of the spectral-sensitivity function depended on the background wavelength, indicating secondary M-cone input. Connectivity models of the outer retina that predict input from all cone types are supported by the finding of tetrachromatic input into Y/B horizontal cells. In contrast, we did not find tetrachromatic input to R/G and monophasic horizontal cells. Chromatic adaptation revealed the spectral-sensitivity function of the turtle UV cone peaking at 372 nm.

Ultraviolet colour opponency in the turtle retina

We have examined the functional architecture of the turtle Pseudemys scripta elegans retina with respect to colour processing, extending spectral stimulation into the ultraviolet, which has not been studied previously in the inner retina. We addressed two questions. (i) Is it possible to deduce the ultraviolet cone spectral sensitivity function through horizontal cell responses? (ii) Is there evidence for tetrachromatic neural mechanisms, i.e. UV/S response opponency? Using a constant response methodology we have isolated the ultraviolet cone input into the S/LM horizontal cell type and described it in fine detail.

Monophasic (luminosity), biphasic L/M (red-green) and triphasic S/LM (yellow-blue) horizontal cells responded strongly to ultraviolet light. The blue-adapted spectral sensitivity function of a S/LM cell peaked in the ultraviolet and could be fitted to a porphyropsin cone template with a peak at 372nm.

In the inner retina eight different combinations of spectral opponency were found in the centre of the receptive field of ganglion cells. Among amacrine cells the only types found were UVSM−L+ and its reverse. One amacrine and four ganglion cells were also opponent in the receptive field surround.

UV/S opponency, seen in three different types of ganglion cell, provides a neural basis for discrimination of ultraviolet colours. In conclusion, the results strongly suggest that there is an ultraviolet channel and a neural basis for tetrachromacy in the turtle retina.

[Assessment of the response to reduced treatment schemes for vivax malaria]

Relapses may occur with long standard treatment of vivax malaria, and these are caused by incomplete patient's compliance. The use of reduced schedules may further better patient compliance, while maintaining the same efficacy, tolerance and minimal adverse reactions. The objective of this study was to test two schedules with reduced doses of chloroquine for vivax malaria and comparing these with the classical schedule. The authors studied 120 outpatients, with vivax malaria, aged over 12 years, submitted to three therapeutic schemes: scheme I: chloroquine phosphate (150 mg) in a dose of 25mg/kg/day for three days (10mg/kg/ day in the first day, 7.5mg/kg/day in the second and third day), plus primaquine (15 mg) in a dose of 0.25mg/kg/day for fourteen days; scheme II: chloroquine, in a single dose of 10mg/kg, plus primaquine in a dose of 0.5mg/kg/day for seven days; scheme III: chloroquine, 10mg/kg in a single dose plus primaquine in a dose 0.5mg/kg/ day for five days. The clinical response to all three therapeutic schemes was satisfactory. The disappearance of malarial symptoms occurred after a maximum 96 hours of treatment, while the asexual parasitaemia clearance occurred within 72 hours, in all therapeutic schemes.

[Comparative study between larval surveys and ovitraps to monitor populations of Aedes aegypti]

This study compares two techniques for detecting the presence of Aedes aegypti: larval surveys and the oviposition trap. In two areas of the municipality of Salvador, Bahia, Brazil were investigated 5,026 households. Larval surveys and oviposition traps were used simultaneously in these households. Different positivity levels (larvae and/or eggs) were detected between and within the two areas. However, only the use of the oviposition trap detected a significant statistical difference between the areas (z = 9,520, p < 0.001). Comparison of the Breteau, Household and Oviposition Indices reveals greater power of detection of positivity in the oviposition trap. There were prevalence ratios of positivity for oviposition trap of 3.4 and 2.1 (for areas 1 and 2 respectively) when compared with larval surveys. The oviposition trap proved to be an economical and operationally viable method, and the most effective in the surveillance of this species.

UV responses in the retina of the turtle

To study processing of UV stimuli in the retina of the turtle, Trachemys dorbignii, we recorded intracellular responses to spectral light from 89 cells: 54 horizontal (47 monophasic, five (R/G) biphasic and two (Y/B) triphasic), 14 bipolar, 12 amacrine, and nine ganglion cells. Spectral sensitivities were measured with monochromatic flashes or with the dynamic constant response method in dark or chromatic adapted states. Stray light and second-order harmonics were also measured. (1) All cells responded to UV stimuli, although none had maximum sensitivity in the UV. (2) Most horizontal, bipolar, and amacrine cells had red-peaked spectral sensitivities. (3) Red adaptation of all monophasic horizontal cells indicated a single red input, except one that had additional peaks in the blue and UV. (4) Responses of biphasic and triphasic horizontal cells to UV light were always hyperpolarizing. Opposition between hyperpolarizing and depolarizing responses at long wavelengths indicates that UV responses were not due to the beta band of red receptors. (5) An unstained spectrally opponent bipolar cell hyperpolarized in the center to green light and antagonistically depolarized in the surround to UV, blue, and green flashes, but hyperpolarized to red. (6) All dark-adapted amacrine cells were red-peaked monophasic cells, but red adaptation broadened their spectral-sensitivity curves or displaced their peaks. An A15, an A18, and an A24 wide-field amacrine cell were stained. (7) A G15 bistratified ganglion cell is shown here for the first time to be spectrally opponent. This UVB/RG cell depolarized to UV and blue and hyperpolarized to red and green. It differs from previously reported turtle ganglion cells in being color opponent in the entire field, not only in the surround, and in showing spatial opponency.

Reproducibility of alkaline antigens of Leishmania major-like and Leishmania (V.) braziliensis evaluated by IgG-ELISA. Comparison of antigens added of a protein inhibitor (PMSF) or not

This paper deals with the analysis of 10 batches of L.major-like and L. (V.) braziliensis antigens added or not of a proteases inhibitor evaluated by means of an IgG-ELISA on three consecutive days using positive standard sera from patients with diagnosis of American Leishmaniasis previously tested for the presence of IgG antibodies by means of ELISA. The statistical analysis showed that for L. (V.) braziliensis the PMSF-containing antigen did not show any difference among batches or days of testing; the L. (V.) braziliensis antigen without PMSF showed statistical significance for differences among batches and a two-way ANOVA showed significant differences between antigens. L.major-like antigen prepared with or without PMSF showed differences among batches; all 3 days of testing displayed differences for the PMSF antigen but only for days 1 and 2 for the antigen without inhibitor. A two-way ANOVA showed differences among batches of the antigens but not for antigens with and without the protein inhibitor. According to the statistical analysis the L.major-like antigen added or not of PMSF has shown that it is the choice antigen for mucocutaneous leishmaniasis serology.

[Case-control design in cardiovascular disease epidemiology. II--Analysis of data]

The wide spread distribution of statistical software recommended for multivariate analysis as well as the ease in handling it can lead the users into adopting wrong measures if they do not pay attention to the theoretical principles behind those methods. With a view to bringing out some of these principles some steps for the data analysis of a case-control study undertaken in the city of S. Paulo-Brazil from March, 1993 to February, 1994 in order to test the association between diabetes mellitus and ischaemic heart disease after adjusting for potential confounders and/or modifiers of effect are presented. Methodologic issues are emphasized in the development of four steps: a) the data bank structure: b) the calculation of statistical power; c) the definition of variables strata and codification and d) the choice of the logistic regression method.

Dietary patterns in Japanese migrants to southeastern Brazil and their descendants

This paper describes the dietary patterns of people of Japanese ancestry living in São Paulo, Brazil. Two cross-sectional surveys using a food frequency questionnaire (in 1989 and 1995) and self-administered three-day food record (only in 1995) were carried out in randomly chosen first-generation (Japan-born) and second-generation (Brazil-born) Japanese living in the city of São Paulo (n = 166), aged 40-69 years at the time of the first survey (1989). Daily intake of rice, bread, milk, fruits and coffee, and infrequent consumption of pork, green tea, black tea, tsukemono (pickled vegetables), seaweed and mushrooms were reported. The mean (+/- standard deviation) daily proportions of energy from fat among Japan-born participants were 27.2 +/- 6.7% for men and 26.2 +/- 6.7% for women. The respective figures for Brazil-born Japanese were 30.1 +/- 7.4% and 29.5 +/- 6.4%. These values were quite close to recent estimates for the general Brazilian population in metropolitan areas (about 30%), but seem to be higher than available data from Japan (25.3%). Dietary changes in this migrant population are discussed with focus on nutrients currently implicated in the etiology of major chronic diseases.

[Reproducibility of data in a study of the risk factors for insulin-dependent diabetes mellitus]

The reliability of information about mothers' and fathers' education, weight and height at birth, history of diarrhoea, duration of exclusive breast feeding and age of introduction of cows' milk products, selected from a structured questionnaire used in home interviewers was examined in a sample of 38 cases and 38 controls from a study related to the risk factors of insulin-dependent diabetes mellitus. The repetition of the questions was done by telephone. The agreement between the answers of both interviewers was verified using the kappa statistic (categorical variables) and the intra-class correlation coefficient (quantitative variables). The results enable one to conclude that the information is reproducible.

IDDM and milk consumption. A case-control study in São Paulo, Brazil

OBJECTIVE

To test the hypothesis that breast-feeding is a protective factor against IDDM and that early exposure to cow's milk is a risk factor for the disease.

RESEARCH DESIGN AND METHODS

A case-control study was conducted in São Paulo, Brazil. A total of 346 diabetic children, aged < 18 years, were identified in two institutions in the city of São Paulo. Duration of exclusive breast-feeding and age of introduction to cow's milk products in infant diet were compared with 346 sex-, age-, and neighborhood-matched control children. All comparisons between diabetic and control children were done using paired tests.

RESULTS

Statistically significant differences were found for the duration of exclusive breast-feeding (P = 0.007) and for the age of introduction to cow's milk products (P = 0.047). Control children had a longer time of exclusive breast-feeding and had received cow's milk later in their diet than the case children.

CONCLUSIONS

The results suggest that a shorter duration of exclusive breast-feeding is a risk factor for IDDM (odds ratio [OR] 2.13; 95% CI 1.8-3.55) and that the introduction to cow's milk products before age 8 days is a risk factor for the disease.

Evaluation of Leishmania antigens preparation and storage for use in enzyme immunoassays

The influence of time and temperature on the storage of an alkaline antigen of L. major-like and L.(V.) braziliensis promastigotes added or not of a proteases inhibitor (PMSF) was evaluated by means of an IgG-ELISA. Antibodies in assays using L. major-like antigen stored at -20 degrees C for 6 months had a statistically lower geometric mean titer (GMT) and different 95% confidence interval limits (CL) than antigens stored otherwise, as assessed by the "t" statistic. The PMSFL. major-like antigen after storage for 6 months at a temperature of 4 degrees C had the same GMT and 95% CL displayed at time zero as well as when storage for 4 and 6 months at -20 degrees C. Significant differences were not found when L.(V.) braziliensis antigens were stored at times and temperatures mentioned; the PMSF antigen stored for 2 months at -70 degrees C resulted in a lower serum GMT and 95% CL than any other, as assessed by the "t" statistic. Antigen performance did not show any statistical difference associated to the addition of PMSF within the same species; the largest difference between antigens was that between PMSF-L. (V.) braziliensis and L. major-like without PMSF.

[Dose-response effect of risk factors for ischemic heart disease in males]

PURPOSE

Several authors have reported hypertension, smoking and hypercholesterolemia as independent risk factors for ischemic heart disease (IHD), but few of them have investigated the existence of a linear gradient related to the levels of these exposures and IHD. We evaluated the effect of different levels of these exposures and IHD after adjusting for known confounders.

METHODS

The study was designed as a case-control and the period of data collection was from March/93 until February/94. The sample was composed of 547 men aged 30-69 years living in the city of São Paulo. We compared 192 cases with 355 controls (172 neighbourhood controls and 183 hospital controls). Logistic regression was the statistical method used to analyse of the data.

RESULTS

The results showed a linear gradient for known duration of hypertension, known duration of hypercholesterolemia and daily number of cigarettes smoked. The variables known duration of diabetes mellitus and duration of smoking did not present such a tendency.

CONCLUSION

Some methodological issues are presented to explain the absence of a linear gradient for known duration of diabetes mellitus and duration of smoking. It is concluded that the dose-response effect detected for known duration of hypertension, known duration of hypercholesteremia and daily number of cigarettes consumed were independent of the presence of major risk factors for ischemic heart disease.

Electrophysiological measurements of spectral sensitivities: a review

Spectral sensitivities of visual systems are specified as the reciprocals of the intensities of light (quantum fluxes) needed at each wavelength to elicit the same criterion amplitude of responses. The review primarily considers the methods that have been developed for electrophysiological determinations of criterion amplitudes of slow-wave responses from single retinal cells. Traditional flash methods can require tedious dark adaptations and may yield erroneous spectral sensitivity curves which are not seen in such modifications as ramp methods. Linear response methods involve interferometry, while constant response methods involve manual or automatic adjustments of continuous illumination to keep response amplitudes constant during spectral scans. In DC or AC computerized constant response methods, feedback to determine intensities at each wavelength is derived from the response amplitudes themselves. Although all but traditional flash methods have greater or lesser abilities to provide on-line determinations of spectral sensitivities, computerized constant response methods are the most satisfactory due to flexibility, speed and maintenance of a constant adaptation level.

[Anemia in the first year of life and its relation to breast-feeding]

INTRODUCTION

Many studies in this field justify the hypothesis that early weaning is one of the causes of anemia in the first year of life. This study seeks to discover the prevalence of iron deficiency anemia and its relation to the duration of breast-feeding among infants aged 0-12 months.

MATERIAL AND METHOD

A sample of 317 infants of four school health centers in the city of S. Paulo (Brazil) was studied. The information about diet was obtained by interviewing the mothers. The presence of anemia was verified by hemoglobin concentration, using the cianometahemoglobin method, and the criteria recommended by the World Health Organization (WHO) were utilized for the diagnosis. The duration of exclusive breast feeding was calculated by using the life table technique for censored data.

RESULTS

The prevalence of anemia was found to be 14.5% for the whole population and 22.6% for infants aged more than 180 days. No association was found between anemia and time of breast-feeding; the median time were the same for both groups, anemic and non-anemic.

COMMENTS

The results observed are more probably related to the demographic characteristics of the population studied and by no means lessen the importance of exclusive breast feeding in the prevention of anemia.

An AC constant-response method for electrophysiological measurements of spectral sensitivity functions

A number of methods have been used in the past to measure spectral sensitivity (S(lambda)) functions of electric responses in the visual system. We present here a microcomputer based, AC, constant-response method for automatic on-line measurement of S(lambda) in cells with or without a sustained tonic response. It is based on feedback adjustment of light intensity to obtain constant peak-to-peak amplitudes of response to a flickering stimulus as the spectrum is scanned between 300 and 700 nm in 4 nm steps. It combines the advantages of: (1) on-line presentation of S(lambda) curves; (2) constant light adaptation; (3) sampling of many points; and (4) fast data collection time. The system can be applied to sensitivity or threshold (e.g., S(lambda), dark adaptation, receptive field) measurements of any electrically recorded visual response.

[Diabetes mellitus and ischemic heart disease: case-control study]

Several works have been reported diabetes as an independent risk factor for ischaemic heart disease. The use of different methodologies have been an obstacle to a comparison of these studies. The study realized has sought to test the association between diabetes and ischaemic heart disease, after adjusting for known confounders and/or modifiers of effect. The study was designed as a case control study and the period of data collection was one year (March/93 to February/94). The cases were compared with three kinds of controls in two base-populations: primary and secondary. The sample was composed of 833 individuals of both genders of 30-69 years of age living in the city of S. Paulo, Brazil. Logistic regression was the statistical method used for the analysis of the data. The results showed that diabetes was not an independent risk factor for IHD. Hypertension, hypercholesterolemia, smoking and family antecedents of cardiovascular diseases were considered major risk factors for ischaemic heart disease. The interaction between diabetes and exposure levels of the others variables did not present statistical significance. Some methodological issues are presented to explain different magnitudes of effect according to the different kinds of controls. It is concluded that the presence of major risk factors in the models contributed to the disappearance of the association between diabetes and ischaemic heart disease.

[Diabetes mellitus and ischemie heart disease. Comparison by gender]

PURPOSE

To test the association between diabetes mellitus and ischaemic heart disease (IHD) in males and females, after adjusting for known confounders and/or modifiers of effect.

METHODS

The study was designed as a case-control and the period of data collection was one year (March/93 until February/94). The association between diabetes mellitus and IHD was evaluated in each one of two groups: one composed by men the other by women, aged 30-69 years living in the city of São Paulo. The respective samples sizes were 547 and 286. Logistic regression was the statistical method used to do the analysis of the data.

RESULTS

There were similar odds ratios in both genders and diabetes was not considered an independent risk factor for IHD. In each one of the groups the variables hypertension, hypercholesterolemia, smoking and familial history were considered independent risk factors to IHD. The interaction between diabetes and exposures levels of other variables was not statistically significant.

CONCLUSION

The presence of major risk factors in the models contributed to the disappearance of the association between diabetes mellitus and IHD.

[The evolution over time of the in-vitro resistance of Plasmodium falciparum to antimalarial drugs in 2 areas of the Brazilian Amazonia with distinct socioeconomic and geographic characteristics]

We evaluated the temporal progression of in vitro P. falciparum resistance to chloroquine, amodiaquine, quinine and mefloquine in two areas with distinct socioeconomical and geographical characteristics: Lourenço, in Amapá state and Paragominas, in Pará state. The former region is essentially an "open" gold mining camp, whereas the latter is one currently undergoing a colonization settlement process, in addition to expanding economical activities which mainly include cattle raising and wood exploitation. Our results show high resistance rates to chloroquine in the two study areas: 79.8% and 68.4% in Lourenço and Paragominas, respectively. Variations in the response of P. falciparum to both amodiaquine and quinine were recorded throughout the study period. On the other hand, no mefloquine P. falciparum resistant strains could be identified, despite the tact we had noted a decrease in sensitivity to this antimalarial drug throughout the study period.

Cranio-orbital approach for the paraclinoidal and anterior communicating aneurysms

Aneurysms arising at the proximal intracranial carotid artery (between cavernous sinus and posterior communicating artery) and at the anterior communicating complex may present with technical difficulties regarding appropriate access without excessive brain retraction. In a series of 15 patients the authors show the use of the cranio-orbital approach, formerly designed in the access of skull base tumors, for these subgroups of aneurysms. They discuss the advantages of a basal avenue in minimizing brain retraction, better anatomical orientation, obviation of tissue ressection and easier extra-dural bone removal. It was not identified any complication due to the described approach.

[The use of stratification and logistic regression model in the data analysis of case-control studies]

Data of a case-control study of esophageal cancer were used as an example of the use of multivariate analysis with stratification and logistic regression. Eighty-five cases and 292 controls were classified according to sex, age and smoking and drinking habits. The point estimates of the odds ratios were similar, and the techniques were considered complementary.

[Risk factors for cancer of the esophagus: a case control study in a metropolitan area of south-eastern Brazil]

The association between esophageal cancer and smoking and drinking habits, instruction and nutritional factors was examined by means of the utilization of data of a case-control study which was undertaken in the city of S. Paulo (Brazil). Eighty five cases were compared with two hundred and ninety two hospital controls, with different diseases, including other kinds of cancer. The crude estimations of the odds ratios were calculated for all the variables. Logistic regression was used in the next steps of the analysis. The drinking habit [odds ratio = 3.68, 95% confidence interval (1.74 - 7.78)], the smoking habit [odds ratio 4.86; 95% confidence interval (1.95 - 12.13)] and the frequent eating of hot pepper [odds ratio = 2.48; 95% confidence interval (1.46 - 4.23)] are important risk factors for the disease. The estimate of odds ratio for smoking ordinary cigarette was 3.43 (1.31-8.97) and for smoking of corn straw hand-rolled cigarrette was of 4.18 (1.38-12.66).

Nonlinear-optical properties of a poly(vinyl alcohol)-polyaniline interpenetrating polymer network

The nonlinear-optical properties of a semi-interpenetrating polymer network of poly(vinyl alcohol) glutaralde-hyde-polyaniline were studied. Large (>/=10(-12) cm(2)/W) and fast (<50 ps) refractive optical nonlinearites were observed. The potential of this novel material for photonic applications is evaluated.

[Cleft lip and palate: case-control study]

This study relates to a case-control analysis for the purpose of verifying the association between oral clefts and possible risk factors. The analysed variables were: place of mother's residence (urban/rural), pollution, parental diseases, mother's diseases during the first four months of pregnancy, intake of drugs related to this period, heredity, smoking habits, alcohol consumption and X-ray examinations during pregnancy or X-ray examinations prior to pregnancy. There were 450 cases of clefts of whom 354 had a cleft lip with or without cleft palate and 96 had a cleft palate. The relative risk (RR) for each variable by was estimated points and at a 95% of confidence interval and multivariate analysis was applied. As regards cleft lip with or without cleft palate, the risk factors are heredity (RR = 4.96), epilepsy in the mother (RR = 2.39) and the intake of drugs such as anti-inflammatory substance in the first four months of pregnancy (RR = 2.59). Related to cleft palate, the risk factors are heredity (RR = 2.82) and pollution (RR = 2.58).

Epidemiological distribution of Plasmodium falciparum drug resistance in Brazil and its relevance to the treatment and control of malaria

With the use of a simple formulary, filled by health agents was established a monitoring programme for responses of P. falciparum to the antimalarial drugs. This monitoring programme is emphasized for the knowledge of the epidemiology of the drug resistance and the control of malaria falciparum in Amazon Basin where occurs more than 95% of Brazilian malaria cases every year. It was demonstrated that still now 4-aminoquinolines have a great importance for the mortality control in areas where just SUCAM (National Health Foundation--Health Ministry) agents are present without any medical assistance. The results obtained permitted the simplification of malaria treatment in Brazil. Important conclusions were established in the field of malaria drug resistance.

"Pararamose": an occupational arthritis caused by lepidoptera (Premolis semirufa). An epidemiological study

The frequency of "pararama" occupational accidents between 1988 and 1990 as well as some associated clinical manifestations are herein reported. Data were collected at an industrial rubber tree plantation, in the northern part of Brazil and compared with data similarly collected from 1971 to 1974 on the same plantation, before starting protective measures. "Pararama" is the popular name of the larval form of a native insect of the Amazonian region, Premolis semirufa. During the study period, the annual average number of latex extractors was 337 and 60 accidents caused by "pararama" were registered. The annual average number of accidents per worker from 1971 to 1974 was 0.117 and in the period of this study, 0.063 (p = 0.061). Nineteen injured subjects were clinically evaluated and 13 of them were symptomatic. There was a statistically significant association between multiple accidents and the presence of symptoms (p = 0.001). "Pararamose", an occupational arthropathy, which may evolve with functional impairment of the affected joint, can be prevented with the latex extractors education and the institution of prophylactic measures, such as the use of gloves, boots and protective glasses.

[Arterial hypertension and possible risk factors]

The results of a cross-sectional (prevalence) study of high blood pressure, carried out in 1987 in Araraquara County in the north of S. Paulo State, Brazil are presented. The group studies numbered 1,199 people, including 533 men and 666 women, of from 15 to 74 years of age. The results show a high prevalence of the disease (32.0% for men and 25.3% for women), with a tendency to increase with age, up to the 40's (men) and the 50's (women). There was also a greater percentage of hypertensives in the mulatto and black groups, in the obese, and among those of lower family income, with a lower level of schooling and with less well remunerated jobs. However, the logistic regression showed very small odds ratios associated with these risk factors, which could be attributed to the way these factors were considered.

[Smoking prevalence in the urban locality of southeastern Brazil]

A cross-sectional study for prevalence of arterial hypertension in the population aged 15-74 years of age of the urban area of Araraquara County, 250 km from the city of S. Paulo, S. Paulo, State, Brazil, in 1987, was performed. The questionnaires presented to 1,199 people (533 men and 666 women) at the interview consisted of regarding sociodemographic variables, as well as the use of tobacco (smoking), the ways in which tobacco was used and the habit of inhaling the smoke. The sample was taken by the procedure of clustering, carried out in three stages. The sample was equiprobabilistic. The prevalence of tobacco smoking was very high being of 45.2% for men and 22.8% for women. The ex-smokers accounted for 15.9% of men and 8.0% of women. The men smoked much more than the women. The poorer smoked more than the richer, in both sexes. Among men, the prevalence of smoking was inversely proportional to duration of schooling, but that difference was not noted in women. As there have been other studies regarding the high prevalence of obesity and high blood pressure, it was concluded therefore that the population of Araraquara, an average town of the affluent urban interior of S. Paulo State, has a high frequency of risk factors for chronic non-transmissible diseases.

Ethnicity and cancer risk in São Paulo, Brazil

Data from the São Paulo Cancer Registry (Brazil) for the period 1969-1974 are used to investigate ethnic differentials in cancer risk. Risks for specific cancers were estimated for mulattos and blacks relative to whites, using a case-control approach with other cancers as controls. For both sexes, blacks and mulattos are at higher risk than whites for cancer of the esophagus, stomach, and liver and for myeloma; for prostate cancer in males; and for gall bladder, pancreas, and cervix uteri cancers in females. Blacks and mulattos are at lower risk than whites for cancer of the colon, lung, larynx (males only), bladder, bone, testis, breast, and corpus uteri and for melanoma and leukemia. Except for lung and colon cancers, for which life-style habits are the main risk factors, these ethnic differences are similar to those observed in the United States.

Proportional cancer incidence according to selected sites--comparison between residents in the city of S. Paulo, Brazil: Japanese and Brazilian/Portuguese descent

The percentual distributions of selected sites of cancer cases according to origin, sex and age are compared. Data were obtained from the Registry of Cancer of S. Paulo (School of Public Health of the University of S. Paulo, Brazil). The reference period for inhabitants of Japanese descent was 1969/78 and for those of Brazilian descent, the period was 1969/75. Standardized Proportionate Incidence Ratios (SPIR) with approximate 95% Confidence Intervals (CI) were evaluated using age specific Incidence Ratios of S. Paulo, 1973, as standards. The results agree with findings of previous works on mortality, but show different patterns according to origin. The well known fact that some sub-groups of a population may be different from the overall group is once again brought to the fore. Attention should be drawn to the differences detected for stomach, skin and prostate, in males, and for stomach, skin, cervix and uterus in females.

Cancer incidence rates among Japanese immigrants in the city of São Paulo, Brazil, 1969-78

Cancer incidence rates among first-generation Japanese immigrants in the city of São Paulo, Brazil, were estimated from the data of the São Paulo Cancer Registry during the years 1969 to 1978. From all registered cases, 2,179 cancer cases of Japan-born residents (1,288 males, 891 females) were selected and age-specific and summary age-adjusted incidence rates (AAIR) were calculated for the selected sites of cancer. The AAIR for all sites except non-melanoma skin cancer was 195.2 per 100,000 population (95 percent confidence interval: 176.4-214.1) in males and 147.3 (134.6-160.0) in females. Stomach cancer had the highest incidence rate of all cancers in both sexes (males, 69.3; females, 32.0). This was followed by cancer of the lung (22.5), esophagus (10.2), colon (8.3), and prostate (7.1) in males; and by breast (24.0), cervix (18.0), colon (8.4), and lung (7.2) in females. When these rates were compared with those among Japanese in Japan, cancer of the stomach and rectum revealed significantly lower rates, while non-melanoma skin cancer, and prostate and breast cancer showed higher rates. No significant increase of colorectal cancer was recognized among Japanese immigrants in São Paulo, contrary to the remarkably high rates of colorectal cancer being observed among Japanese immigrants in the US.

Cancer mortality among Japanese residents of the city of São Paulo, Brazil

Death certificates of Japanese residents of the city of São Paulo, Brazil from 1979 to 1981 were analyzed for cancer deaths by means of the standardized mortality ratio (SMR) and the standardized proportional mortality ratio (SPMR). Compared with residents of Japan, a significantly higher SMR value was obtained from Japan-born residents of São Paulo for prostate cancer, whereas lower values were obtained for cancer of the liver and gall-bladder in both sexes, of the esophagus and rectum in males, and of the lung in females. SMR values were higher for cancer of the stomach in both sexes but lower for those of the esophagus and prostate in males and of the gall-bladder and breast in females, when compared with the general population of São Paulo. Among Japan- and Brazil-born residents, stomach cancer in women revealed a significant stepwise decrease by generation when SPMR was used as an indicator. The high proportion of stomach cancer in males, however, was as high among the Brazil-born generation as in Japan. The SPMR of liver cancer decreased to the low level of the general population of São Paulo, even among the first generation. These changes in cancer patterns are discussed in relation to those among Japanese residents in the United States.

Comparative study of temporal summation and response form in hymenopteran photoreceptors

1. Temporal summation was measured in green-sensitive photoreceptors of seven hymenopteran species with various life styles: three bees, Melipona quadrifasciata quadrifasciata, Trigona spinnipes and Bombus morio; one wasp, Polistes canadensis; and three ants, Pseudomyrmex phyllophilus, Camponotus rufipes, and Atta sexdens rubropilosa. In all species approximate agreement with Bloch's law was confirmed. 2. Critical durations (tc), which varied from 10 ms (Pseudomyrmex) to 46 ms (Atta), are discussed in relation to the life styles of the species and to the mechanisms causing the differences. 3. The direct measures of critical duration obtained are compared to estimates made by convolution or integration of impulse responses measured here in one species and from published data. Linear convolution of typical impulse responses is shown to result in significant departures from Bloch's law, a fact that seems to have been overlooked in the literature. 4. The method used to measure temporal summation involved recording responses to 300-ms stimuli at various intensities; the form of these responses varied greatly from species to species. Possible causes of these variations are discussed.

Comparison between autoantibodies in malaria and leprosy with lupus

Sera from 16 patients with falciparum malaria, 16 patients with vivax malaria and 31 patients with leprosy were tested for autoantibodies to intracellular proteins and nucleic acids. Precipitating antibodies to soluble protein extracts were not detected in any serum. Sera from malaria patients showed prominent immunofluorescence staining of the HEP2 nuclear membrane as well as frequent 75% (24/32) and intense Western blot reactivity. In contrast, only 20% and 36% of patients with leprosy had positive immunofluorescence or positive immunoblots respectively, and reactivity was weak in most cases. Neither the malaria nor leprosy sera contained autoantibodies with specificities similar to the characteristic lupus autoantibodies such as double stranded DNA (dsDNA), Ro/SSA, La/SSB, Sm, RNP and P proteins. Low levels of antibodies to single stranded (ssDNA) were however found in 11 (34%) malaria sera and in seven (23%) leprosy sera. Thirteen percent of patients with leprosy had anti-histone antibodies. These findings demonstrate considerable differences in the capacity of infectious agents to induce autoantibodies and also the infrequency with which autoantibodies characteristic of idiopathic systemic lupus erythematosus are induced.

[Concentration of polychlorobiphenyl in the population of Greater São Paulo, Brazil]

Os policloretos de bifenila (PCBs), cuja utilização iniciou-se em 1930 em sistemas fechados (capacitores e transformadores elétricos) foram observados no ambiente em 1966, atingindo a cadeia alimentar e acumulando-se no tecido subcutâneo de seres humanos; ao mesmo tempo, foi possível mostrar que esses produtos químicos são potencialmente nocivos para a saúde humana. Como em 1976 os PCBs foram encontrados no tecido gorduroso de pequena amostra da população brasileira, decidiu-se fazer um estudo mais amplo, analisando-se por cromatografia de fase gasosa a gordura do tecido celular subcutâneo de 189 pessoas, de ambos os sexos, que tinham sofrido morte violenta. Foram encontrados níveis médios de 0,8661 ppm em indivíduos do sexo masculino, que apresentaram aumento linear das concentrações de acordo com a idade, o que não foi observado entre os do sexo feminino, onde os valores médios de acúmulo foram de 1,4530 ppm. Do total de amostras, 12,7% apresentaram níveis superiores a 1,95 ppm. É discutida a importância do achado e são assinaladas as medidas de proteção da população brasileira exposta aos PCBs.

[Perinatal morbidity and mortality in maternity hospitals. III--Congenital abnormalities in living births]

Realizou-se estudo das anomalias congênitas encontradas em recém-nascidos vivos, em nove maternidades, durante o ano de 1981-1982. O material é parte de uma pesquisa desenvolvida em sete maternidade do Estado de São Paulo, uma do Rio de Janeiro e uma de Florianópolis, Santa Catarina (Brasil), no período de agosto de 1981 a julho de 1982, quando foram coletados dados sobre todos os nascimentos ocorridos nesses nove serviços. As anomalias congênitas foram definidas como as descritas no XIV.° capítulo da Classificação Internacional de Doenças - 1975, 9ª Revisão, tendo sido utilizada essa classificação para codificá-las. Na análise estatística foram utilizados o X² (com um grau de liberdade), o teste de inclinação para proporções ("Trend test") e a técnica de Berkson para a verificação da hipótese de aderência à distribuição de Poisson. Em 12.782 recém-nascidos vivos, 286 (2,24%) apresentavam algum tipo de anomalia congênita, tendo havido 26 (0,20%) crianças com duas anomalias, 9 (0,07%) com três e duas (0,02) apresentando quatro tipos de malformações congênitas. As deformidades osteomusculares congênitas (código 754 da CID) foram as mais freqüentes (19%);segue-se as outras anomalias congênitas do coração (746) com uma freqüência de 14,1%. Ao se analisar a prevalência dessas malformações pela idade da mãe nota-se que há um aumento da prevalência à medida que a idade avança, apenas para Sindrome de Down (758).

Single-dose kinetics of mefloquine in Brazilian male subjects

Ten male subjects from a region of the state of Pará, Brazil, where malaria is endemic received a single oral dose of 1000 mg mefloquine. The plasma levels of the drug and of its metabolite, 2,8-bis(trifluoromethyl)-4-quinolinecarboxylic acid, were determined densitometrically on thin-layer chromatography plates. The pharmacokinetic parameters obtained fell well within the range of values reported previously for Africans and Caucasians.

A phase II/III double-blind, dose-finding clinical trial of a combination of mefloquine, sulfadoxine, and pyrimethamine (Fansimef) in falciparum malaria

Fansimef is a combination of 250 mg mefloquine (base), 500 mg sulfadoxine, and 25 mg pyrimethamine per tablet. One hundred and fifty adult male Brazilian patients at Belém (Pará), who had peripheral blood smears positive for Plasmodium falciparum, with or without clinical symptoms of falciparum malaria, were treated in a double-blind randomized fashion with either one, two or three tablets of Fansimef. Of those receiving one tablet (48 patients), 81% were cured and 19% exhibited RI recrudescences. All the patients receiving two or three tablets of Fansimef (49 patients in each group) were cured. The rates of initial clearance of parasitaemia and fever were similar in all treatment groups. Tolerance was good at all dose levels. The main side-effects included nausea, vomiting, dizziness, diarrhoea and abdominal pain, but these were mild and transient and required no specific treatment. The incidence of vomiting and nausea was highest in patients given the three-tablet dose. The results of various haematological, biochemical and urine analyses were not adversely altered by the administration of Fansimef.

Decline in cardiovascular disease mortality in the city of S. Paulo, Brazil, 1970 to 1983

Mortality from all causes as well as from the great groups of cardiovascular diseases for the residents of the city of S.Paulo, Brazil, of the ages-group 40-69, for the years 1970 to 1983, has been analysed by means of the specific death rates. During this period a statistically significant decline was observed (28% on the average for ischemic heart diseases and 16% for cerebrovascular diseases). The death rates for the group 40-69 years old for both sexes were age-standardized and compared with those of 27 industrialized countries. The S.Paulo standardized death rates ranked almost always very high in the comparisons.

[Characterization of P. falciparum strains obtained from relapsed patients]

A caracterização de cepas de P. falciparum coletadas de três pacientes internados no Centro de Provas Clínico-Farmacológicas do Hospital Barros Barreto (Belém, PA), através da eletroforese em acetato de celulose para duas enzimas (GPI e ADA), assim como através de testes de sensibilidade para duas drogas, cloroquina e mefloquina, permitiram observações da variação dos tipos enzimáticos em um dos pacientes e modificação no nível de sensibilidade à cloroquina em outro, tanto em amostras obtidas da infecção original, como em cada uma das recrudescências.

[Multivariate analysis of risk factors for low birth weight in live births in the municipality of São Paulo, SP (Brazil)]

Em casuística de 20.850 nascidos vivos não gemelares ocorridos em 31 maternidades do Município de São Paulo, SP, Brasil (parte da casuística total do Estudo Antropométrico do Recém-nascido Brasileiro), procurou-se identificar fatores de risco para o baixo peso ao nascer (peso < 2.500 g), tendo sido estipulados a priori, para estudo, os fatores escolaridade materna, estado marital, idade materna, paridade, peso pré-gestacional, tabagismo na gravidez e assistência pré-natal. A partir de análise multivariada pela técnica de modelos log-lineares, foram identificados quatro fatores de risco significativos: "ausência de assistência pré-natal", "peso pré-gestacional < 50 kg", "tabagismo na gestação" e "idade materna < 20 anos". O risco relativo associado a "ausência de pré-natal" foi de 2,2 nas mães de escolaridade inferior ao ginásio completo e de 3,4 nas de escolaridade igual ou superior àquele nível. Os riscos associados às características maternas de peso, tabagismo e idade foram respectivamente 1,9, 1,7 e 1,4 e independentes da escolaridade materna. Considerando-se além da magnitude dos riscos detectados a freqüência com que os fatores de risco se apresentaram na população, constatou-se que o peso pré-gestacional insuficiente, o tabagismo na gestação e a ausência de assistência pré-natal, particularmente em mães de "baixa escolaridade", são fatores cujo controle exerceria importante decréscimo na incidência de recém-nascidos de baixo peso. Assim sendo, tais fatores deveriam ser cuidadosamente considerados em programas de intervenção.

[Multivariate analysis; an example using a log-linear model]

Apresenta-se de forma resumida análise multivariada de dados categóricos, usando modelo log-linear para a situação de uma tabela de contingência 2 x 2 x 2.