Effects of neonatal exposure to cocaine in the development of the neurotransmitters retinal systems: an immunocytochemical and neurochemical study

The visual system of rodents is affected if exposure to drugs, e.g., cocaine, occurs during prenatal or early postnatal development. This study aims to evaluate, in an experimental model of neonatal exposure to cocaine in the rat, the immunocytochemical expression of tyrosine hydroxylase in the retina and the levels of different neurotransmitters and its metabolites. Male Wistar rats were given 15 mg cocaine hydrochloride/kg body weight/day, subcutaneously, in two daily doses, from the day after birth (PND1) to PND6, 13, and 29. Controls were given 0.9% saline. Groups of rats were perfused at PND7, 14, and 30 with fixative, and the retinas were processed as wholemounts, and immunostained with the antibody anti-TH. Other groups were decapitated, and the retinas were dissected and processed by high performance liquid chromatography with electrochemical detection (HPLC-EC) for determination of dopamine and metabolites (DOPAC and HVA). A reduction in the retinal surface area was detected in the PND30 cocaine group, and a decrease in the density of the small TH-IR cells was found in the PND14 cocaine group although not reaching significant levels. The other quantitative parameters did not differ between the control and cocaine groups. The levels of neurotransmitters did not significantly differ between the groups at any age. These results show a differential vulnerability of the dopaminergic system of rats exposed neonatally to cocaine when compared with the effects found after prenatal exposure to the same drug.

Acute toxicity test with Daphnia magna: an alternative to mammals in the prescreening of chemical toxicity?

In this study, the association between the acute toxicity of 15 compounds to Daphnia magna, expressed as 24- and 48-h LC(50) values, and the corresponding oral LD(50) values for the rat was tested. Since there was evidence of a strong relationship between the two species, the sample was extended to 54 cases by including the values for acute toxicity to D. magna and rat of more chemicals published by other authors. Thus, a total of 54 data points were further used to ascertain the relationship between the acute toxicity of chemical compounds to D. magna and that to the rat. To summarize its validity, the D. magna test is more specific than sensitive as an indicator of toxicity to the rat. When it is used with a chemical that has a high probability of being very toxic to D. magna (LC(50)< 0.22 mg/L), the test provides considerable information if it is positive, virtually giving evidence of toxicity to the rat (with a probability of 0.83). On the other hand, a negative test (D. magna LC(50)>0.22 mg/L) has a probability of correctly assigning nontoxicity to the rat equal to 0.74. This study and results published by other authors provide good evidence of the applicability of using invertebrate tests as prescreening methods, thus considerably reducing the number of mammals required in toxicity testing.

[Diagnosis of intestinal amebiasis using coproscopic and immunological methods in a population sample in greater metropolitan Belém, Pará, Brazil]

We compare diagnostic methods for Entamoeba histolytica in fecal samples from the city of Belém, Pará, Brazil. We analyze stool samples from children and adults (Group I); stool and serum samples from adults (Group II); and stool samples from children (Group III). In groups I and III, we used direct examination with lugol (DM), Faust et al (FM), and ELISA (detection of E. histolytica anti-GIAP coproantigen) and in group II, DM, iron hematoxylin staining (IHS), FM, ELISA, and the indirect immunofluorescence test (IFAT) for detection of IgG antibodies. Positivity was 10.50% by DM plus FM and 28.99% by ELISA. There was no correlation between positivity and age group. In Group II (n = 87), the positive rate was 4.59% by DM plus FM, 8.04% by IHS, 4.59% by IFAT, and 21.83% by ELISA. The ELISA test was the most sensitive for all groups. IFAT alone is still not a useful tool for diagnosis of E. histolytica infection. The ELISA test is simple, performed in one-third of cases used for IHS and IFAT, and greatly improves quality of diagnosis. We recommend this as the method of choice for diagnosis of suspected E. histolytica infection.

Spirituality and prayer research: a select annotated bibliography

As the world has become more complex, so too have our ethical conceptualizations about it. In the 1970s, ethical theories and principle-based bioethics dominated. Then clinicians and scholars began to experience the limitations of these two approaches when used alone. In the 1980s, women's voices began to be heard through both feminist ethics and the ethic of care. In addition, virtue ethics and casuistry again gained recognition. During the 1990s and as we are about to enter the 21st century, ethics has expanded to capture the concepts of narrative ethics and spirituality. This select annotated bibliography focuses on spirituality and on prayer research.

Handouts as an educational support for the teaching/learning program in clinical anatomy

Handouts were developed to support the program of Clinical Anatomy in the Medical School of Porto, and since 1996/97 alterations have been made to improve their format and content with our educational objectives in mind. A questionnaire was designed to evaluate the opinion of second-year medical students enrolled in the program. Students were asked about their approval of the way handouts were organized and their usefulness, especially for lectures and practical sessions on physical examination, sectional and imaging anatomy, anatomical variations and malformations and case studies. Of 152 students, 138 (90.8%) returned the questionnaire. To describe the relationship between the value of handouts and several aspects of their organization and adequacy, the Spearman rank correlation coefficient was used for lectures, and canonical correlation for the various practical sessions. Students fully approved the way the handouts of lectures and practical sessions were organized (81.8% and 87%, respectively), their presentation (74.6% and 86.2%), relevance (88.3% and 85.5%), usefulness in understanding the lectures (77.6%) and their value in preparing for practical sessions (83.3%). Handouts were considered highly useful for case studies (90%), physical examination (81.9%) and sectional anatomy (65.7%). Students stating a higher degree of utility of the handouts emphasized that they were useful-indeed essential-in preparing for sessions, and noted their objectivity. The evaluation of the handouts was highly favorable and showed that they can be used as a guide through the complexities of an innovative program of Clinical Anatomy.

Clinical heterogeneity of autosomal recessive spastic paraplegias: analysis of 106 patients in 46 families

BACKGROUND

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders characterized by progressive and predominant spasticity of the lower limbs, in which dominant, recessive, and X-linked forms have been described. While autosomal dominant HSP has been extensively studied, autosomal recessive HSP is less well known and is considered a rare condition.

OBJECTIVE

To analyze the clinical presentation in a large group of patients with autosomal recessive HSP from Portugal and Algeria to define homogeneous groups that could serve as a guide for future molecular studies.

RESULTS

Clinical features in 106 patients belonging to 46 Portuguese and Algerian families with autosomal recessive HSP are presented, as well as the results of molecular studies in 23 of these families. Five phenotypes are defined: (1) pure early-onset families, (2) pure lateonset families, (3) complex families with mental retardation, (4) complex families with mental retardation and peripheral neuropathy, and (5) complex families with cerebellar ataxia. Six additional families have specific complex presentations, each of which is unique in the present series. Pyramidal signs in the upper limbs and pes cavus are frequent findings, while pseudobulbar signs, including dysarthria, dysphagia, and brisk jaw jerks, are more frequent in the complex forms. The complex forms have a poorer prognosis, while pure forms, particularly those with early onset, are more benign. One Algerian pure early-onset kindred was linked to the locus on chromosome 8, previously reported in 4 Tunisian families. Two of the Portuguese kindreds with complex forms (one with mental retardation and the other associated with hypoplasia of the corpus callosum) showed linkage to the locus recently identified on chromosome 16.

CONCLUSIONS

Although autosomal recessive HSP represents a heterogeneous group of diseases, some phenotypes can be defined by analyzing a large group of patients. The fact that only one Algerian family was linked to chromosome 8 suggests that this is a rare localization even in kindreds with the same ethnic background. Linkage to chromosome 16 was found in 2 clinically diverse Portuguese kindreds, illustrating that this locus is also rare and may correspond to different phenotypes.

A Daphnia magna first-brood chronic test: An alternative to the conventional 21-Day chronic bioassay?

In this study a comparison was made of the results obtained in Daphnia magna chronic bioassays after first-brood release and after 21 days of exposure, using inhibition of normal reproduction and growth as effect criteria and EC10, EC20, EC50, no-observed-effect concentration (NOEC), and lowest-observed-effect concentration (LOEC) as statistical parameters. Test substances were sodium bromide (NaBr), 3,4-dichloroaniline (DCA), cadmium, and parathion. For NaBr, DCA, and cadmium, toxicity evaluated after the first-brood release was similar to toxicity evaluated after 21 days, using reproduction as end point. Parathion did not affect either reproduction or growth. Thus, LC50, NOEC, and LOEC were calculated using mortality as the endpoint for parathion. Results indicate that the period until release of the first brood is sufficient to predict the toxicity of some chemicals to D. magna. Values estimated on the basis of a logistic model (EC10, EC20, and EC50) were more appropriate than NOECs and LOECs for evaluating toxicity of the test substances. Furthermore, classic endpoints used for the evaluation of chronic toxicity (inhibition of normal reproduction and growth) may not be adequate to evaluate the sublethal toxicity of compounds that induce cumulative effects leading to mortality within the test period and causing no observable effects on the reproduction and growth of the species. Endpoints indicative of biochemical stress or effects on specific targets of the test compound may be useful in sublethal toxicity evaluation.

Flexible foraging strategy of Cory's shearwater, Calonectris diomedea, during the chick-rearing period

Procellariiformes are well known for their low rates of food provisioning to their slow-growing chicks. In some species, the patterns of food delivery to chicks have been deduced from changes in their weight, obtained from periodic weighings. However, the behaviour of individual parents cannot be resolved using this method. In this study, we used a periodic weighing protocol with Cory's shearwater chicks on Selvagem Grande island, in the northeast Atlantic. In addition, we used an automatic logging system to examine the attendance of individual parents. In 1997, the chicks were fed infrequently, and were in significantly poorer condition, than in other years and at other colonies. This suggests that the adults were experiencing some difficulties in finding an adequate food supply close to the colony. Under these conditions, individual parents adopted a dual provisioning strategy, making both short and long foraging trips, a previously undescribed behaviour in any northern hemisphere petrel species. Although meals delivered to chicks were larger after long trips than after short trips, the average amount of food provisioned per day spent at sea decreased with increasing trip length, and so chicks did not benefit from longer trips. This finding suggests that long trips can be used to restore the adult's body condition, presumably depleted during short trips as shown previously for some petrels and albatrosses. The adoption of this flexible foraging strategy, which differs from the uniform intervals observed in Cory's shearwaters experiencing situations of 'normal' food abundance, may represent a mechanism through which breeding birds compromise between the needs of their chicks and the maintenance of their own body condition. Copyright 1998 The Association for the Study of Animal Behaviour.

delta-Aminolevulinate dehydratase inhibition by ascorbic acid is mediated by an oxidation system existing in the hepatic supernatant

The effect of ascorbic acid (AA) on hepatic delta-aminolevulinic acid dehydratase (ALA-D) activity was studied. AA decreased enzyme activity by reducing maximum velocity and tended to increase the Michaelis constant. ALA-D inactivation by AA occurred similarly both in air and argonium atmosphere incubation. DTT reduced considerably the inhibitory effect of AA on ALA-D, but glutathione was ineffective in reversing inactivation. These data indicate that inhibition occurs mainly due to an acceleration of the oxidation rate mediated by the hepatic supernatant utilizing AA in sulfhydryl groups of cysteine residues present at the ALA-D active site. AA probably acts on cysteine from the ALA-D B site since cucumber and radish leaves ALA-D was not inhibited by AA (up to 16 mM). The addition of free radical scavengers to the medium did not alter ALA-D inactivation caused by AA, indicating that active oxygen species formed during AA oxidation were not directly related to -SH oxidation. The chelation of zinc ions from the enzyme by EDTA turned ALA-D more susceptible to the inhibitory effect of AA. This effect seems to involve mainly ZnB, which is known to bind to four cysteines. The present data suggest that AA may participate in the regulation of the heme biosynthesis pathway by promoting a reversible inactivation of ALA-D.

Developmental exposure to methamphetamine: a neonatal model in the rat

Taking into account that methamphetamine (MA) is a popular recreational drug among young adult women, i.e., in gestational age, the present model aims to assess the effects of its exposure during development. In this experimental model, MA effects are assessed in the rat during the first month of life, regarding both general growth parameters, and gross morphological effects in the retina as part of the evaluation of sensory systems. Experimental animals were obtained from 60-day-old nulliparous females. Litters were culled to 8 pups (4 males and 4 females, whenever possible), individually marked and weighed every two days. Experimental groups received 10 mg (+)methamphetamine hydrochloride kg body weight/day, subcutaneously, twice daily, from postnatal day (PND) 1 to the day before sacrifice; control groups received isovolumetric doses of saline, in the same protocol. Pups were weaned on PND 21. Groups were sacrificed on PND 5, 7 and 30. Animals exposed to MA presented increased percentage of retinal hemorrhages (18, 7 and 11% on PND 5, 7 and 30, respectively) compound to control groups (2% on PND 7, 0% on PND 5 and 30). On PND 30, the mean body weight of males exposed to MA was 75% of the mean weight of male controls, whereas for females, mean body weights were 70% of those of female controls. These findings support the view that developmental parameters in the rat are deleteriously affected by early exposure to MA.

Differences in the frequency of cytokine-producing cells in antigenemic and nonantigenemic individuals with bancroftian filariasis

Individuals with clinical manifestations of lymphatic filariasis may be currently infected or not. Twenty-five individuals from a Wuchereria bancrofti-endemic area of Brazil were classified as being asymptomatic microfilaremic individuals, antigenemic individuals with clinical filariasis, or nonantigenemic individuals with clinical filariasis. Intracellular cytokine staining of mitogen-stimulated peripheral blood mononuclear cells (PBMC) showed that the frequency of either gamma interferon (IFN-gamma)- or interleukin-4 (IL-4)-producing cells was higher in the nonantigenemic individuals with clinical filariasis than in the asymptomatic microfilaremic individuals (geometric means, 22.1 versus 10.7% [P = 0.02] and 2.9 versus 1.4% [P = 0.01], respectively). When the asymptomatic microfilaremic individuals and antigenemic individuals with clinical filariasis were grouped together to constitute all actively infected individuals, the frequency of IFN-gamma-producing cells was also lower than in the nonantigenemic individuals with clinical filariasis (P = 0.04). Likewise, the frequency of IL-4-producing cells in the actively infected individuals was also lower than in the nonantigenemic individuals with clinical filariasis (P = 0.02). No differences in the frequency of IFN-gamma-, IL-4-, or IL-5-producing cells in purified CD4 T lymphocytes were found among the groups. These findings suggest that the presence of antigenemia, which is an indicator of current active infection, is closely associated with the frequency of IFN-gamma- and IL-4-producing cells in lymphatic filariasis. The differences found in the frequency of cytokine-producing cells among the three groups appear to be due to a subset of cells other than CD4 T cells.

Hereditary ataxias and spastic paraplegias: methodological aspects of a prevalence study in Portugal

A project for studying the prevalence of hereditary ataxias (HA) and familial spastic paraplegias (FSP) in Portugal was set up in 1993. The ascertainment of patients in previous prevalence studies relied mainly on the information of hospital admissions and out-patient contacts with the neurology and other related departments at central hospitals covering the whole region surveyed. Many patients might be overlooked if large populations were studied using this method, since registers at central hospitals are very incomplete and for most part not yet computerized. On the other hand HA and FSP are rare diseases appearing in family clusters, and it would be unreasonable to undertake a sample survey based upon a suitable frame of the Portuguese population. Therefore we decided to carry out a two-phase prevalence survey at district level, involving the collaboration of all physicians working in the district health institutions and the population, in the screening of eligible subjects in phase 1. All subjects screened as positive were examined by a neurologist in phase 2. This method provided a direct estimate of false positives and false negatives were all patients also examined in phase 2, who came to our knowledge using other sources of information. The prevalence of hereditary ataxias and spastic paraplegias in the pilot district was 6.4 per 100,000 inhabitants. The sensitivity of the screening procedure was 81.2% and the predictive value of a positive screening was 25%. Considering the geographically circumscribed district nature of the populations to be studied, the comprehensive sources of case identification used and the high adherence of the health professionals involved, we believe that this method can be widely used, particularly in countries with similar health care services.

Air quality inside the passenger compartment of a bus

The indoor air quality in the passenger compartment of an intercity bus is studied. A system used for the remotion of the contaminants from the compartment, based on an extraction duct, was projected using a simple, unidimensional flow model with capability to predict the air exchange rate as a function of the vehicle velocity. Some tests using tracer gan methods were performed in a real vehicle with the contaminant remotion system mounted, in order to validate the calculation model and evaluate the performances of the system. A good agreement between the predicted and the experimental results was verified and the obtained air exchange rate was quite reasonable when compared with the former situation, without extraction duct.

Use of writing portfolios for interdisciplinary assessment of critical thinking outcomes of nursing students

This article discusses an interdisciplinary research project in which faculty from nursing and english collaborated in the assessment of students' critical thinking skills as reflected in writing portfolios. Faculty reviewed students' writing portfolios and then corresponded on email from two different universities about evidence of critical thinking in the portfolios. Findings suggest that writing portfolios can provide important evidence of critical thinking outcomes. To do this, however, faculty need to design writing assignments to foster critical thinking skills, helping students to think not only about learning to write, but also about using writing to learn.

Learning in the Africanized honey bee: Apis mellifera L

Several series of experiments are reported that investigate learning in the Africanized honey bee. In the first series, classical conditioning of proboscis extension was studied by confining bees to small metal tubes where they received pairings of an odor with a 3-s feeding of sucrose. After a number of odor-sucrose pairings, the bees began to extend their proboscis to the odor. Controls include Unpaired, Discrimination, and Pseudoconditioning Groups. This technique was used to look at conditioning to a light CS, and to the odors of beeswax, geraniol, citral, and hexanal. The results indicate that acquisition was best when sucrose was paired with the odor of beeswax. Conditioning to the remaining odors was roughly similar, but acquisition did not occur using a light. In a second series of experiments, odors were no longer followed by sucrose feedings and the conditioned response slowly disappeared. With the exception of geraniol as a CS, this extinction effect did not occur if the animals continued to be fed on an unpaired schedule. In a third series of experiments, conditioned inhibition was demonstrated when geraniol was used as conditioned stimuli, but no effect was found when the odors of hexanal, citral and wax were used. In a fourth series of experiments, unrestrained bees flew back and forth from the laboratory to the hive, where they were taught to distinguish targets based on color and odor. With this technique, color and odor discrimination in the Africanized bees was demonstrated. In addition, it was found that more intruder bees visited the experimental station when the stimuli used were olfactory rather than visual.

[Epidemiological pattern of lymphatic filariasis in children living in endemic areas]

OBJECTIVE

Lymphatic filariasis still represents a major public health problem in the city of Recife. In spite of the fact that previous surveys had already shown high frequency of microfilaraemia in pediatric population, the prevalence of filarial disease and the microfilaraemic pattern of this group were unknown. This paper describes the clinical-epidemiological pattern of filariasis in children and adolescents living in two highly endemic areas of Recife.

METHODS

The parasitological survey was done through a census carried out between December 1990 and July 1991. Thick drop technique (45 micro l) was performed on a total of 1,464 children and adolescents between the ages of 5 and 14, of whom 967 were submitted to clinical examination. Positive cases had their blood recollected (60 micro l) to measure the microfilaraemic density.

RESULTS

The microfilaraemia prevalence was 6.4 %. In the age groups of 5 to 9 and 10 to 14 a microfilaraemia prevalence of respectively 4.6% and 8.3% was observed. The microfilaraemic density varied from 3 to 864 microfilariae per 60 microl of blood, there having been no statistically significant difference between the sexes and age groups (p<0.05). 6 cases (0.6 %) of acute filarial disease and 11 of chronic filarial disease (1.1%) were identified, hydrocele being the principal manifestation found. Lymphadenopathy was found in 22% of the children, statistical association with microfilaraemia being observed (p<0.001).

CONCLUSIONS

The results of the parasitological survey show the strong presence of children in the contingent of microfilaraemic individuals, indicating an early and intense exposure to filariasis in the population studied.

Synovial sarcoma: immunohistochemical expression of P-glycoprotein and glutathione S transferase-pi and clinical drug resistance

Our purpose was to study the role of the expression of P-glycoprotein (Pgp) and glutathione S transferase-pi (GST-pi) in predicting the response to chemotherapy, relapse-free interval, and survival of patients with synovial sarcoma (SS). Thirty-seven cases of primary SS, without regional lymph node or distant metastases, were studied. There were 17 females and 20 males, ranging in age from 7 to 81 years (median, 31 years) with tumors located in the lower extremity (n = 24) upper extremity (n = 5) and trunchus (n = 8). The cases were retrospectively studied without knowledge of clinical course to compare the immunohistochemical expression of Pgp and GST-pi, flow cytometry parameters (ploidy and % of cells in S+G2 phases), and PCNA and Ki-67 labeling of primary tumors before any therapy, with that observed in local recurrences and metastases after chemotherapy. The relationship of the aforementioned parameters with clinicopathological features (gender, age, and histo-blood group of the patients, size, location, histological subtype. TNM stage, and clinical response to chemotherapy of the tumors) was also evaluated. Results revealed that Pgp and GST-pi were expressed in 29.7% and 40.5% of the cases, respectively. In 48.6% of the tumors there was expression of a least one of the drug resistance markers. The markers were coexpressed in 25.0% of the tumors. The prevalence of Pgp expression was lower, but not significantly, in stage I-II (17.6%) than in stage III (40.0%) tumors, and also in cases without clinical progression (16.7%), than in cases with (36.0%). No such differences were observed for GST-pi expression. Pgp and GST-pi expressions were significantly associated with biphasic SS and were particularly noticeable in solid/glandular areas of biphasic SS. The expression of the drug resistance markers was not significantly associated with gender, age, and histo-blood group of the patients, dimension, location, and proliferative activity of the tumors; it was also not significantly related to relapse-free interval and survival of the patients. The expression of Pgp and GST-pi was not significantly associated either to response to chemotherapy or influenced by chemotherapy. We conclude that Pgp and GST-pi expressions are not good predictors response to of the chemotherapy in patients with localized SS. Other drug resistance mechanisms may be active in SS.