Investigations on the biology,epidemiology, pathology and control of<Emphasis Type="Italic"> Tunga penetrans</Emphasis> in Brazil: I. Natural history of tungiasis in man

Tungiasis is an important health problem in poor communities in Brazil and is associated with severe morbidity, particularly in children. The causative agent, the female flea Tunga penetrans, burrows into the skin of its host, where it develops, produces eggs and eventually dies. From the beginning of the penetration to the elimination of the carcass of the ectoparasite by skin repair mechanisms, the whole process takes 4-6 weeks. The present study is based on specimens from 86 patients, for some of whom the exact time of penetration was known. Lesions were photographed, described in detail and biopsied. Biopsies were examined histologically and by means of scanning electron microscopy (SEM). Based on clinical, SEM and histological findings, the "Fortaleza classification" was elaborated. This allows the natural history of tungiasis to be divided into five stages: (1) the penetration phase, (2) the phase of beginning hypertrophy, (3) the white halo phase, (4) the involution phase and (5) residues in the host's skin. Based on morphological and functional criteria, stages 3 and 4 are divided into further substages. The proposed Fortaleza classification can be used for clinical and epidemiological purposes. It allows a more precise diagnosis, enables the assessment of chemotherapeutic approaches and helps to evaluate control measures at the community level.     

Analysis of the coxsackievirus B-adenovirus receptor gene in patients with myocarditis or dilated cardiomyopathy

Myocarditis and dilated cardiomyopathy (DCM) are common causes of morbidity and mortality in children and adults, most commonly due to infection with coxsackievirus B or adenovirus. Increased expression of the common human coxsackievirus B-adenovirus receptor (CAR) has been reported in patients with DCM. We investigated the CAR gene in patients with acquired or familial myocarditis/DCM for mutations/polymorphisms. Several polymorphisms or intronic substitutions, distant from the intron-exon boundaries, were identified but no mutations. Based upon these data it appears that CAR gene mutations are not a major host determinant in the development of myocarditis and DCM.     

Decreased prefrontal 5-HT2A receptor binding in subjects at enhanced risk for schizophrenia

The brain serotonin-2A receptor (5-HT_2AR) has been implicated in both the pathology of schizophrenia and the therapeutic action of atypical antipsychotics. However, little is known about the 5-HT_2AR status before the onset of schizophrenia and before the exposure to antipsychotics. We used [¹⁸F] altanserin and positron emission tomography (PET) in a pilot study of 6 individuals suspected to be at elevated risk for schizophrenia and seven age-matched controls to test the hypothesis that regional 5-HT_2AR binding is altered in the prodromal stages of schizophrenia. Distribution volume ratios (DVRs) as a proxy for 5-HT_2AR availability were significantly reduced in prefrontal cortex regions of at-risk subjects, implicating early abnormalities of serotonergic neurotransmission that antecede the onset of schizophrenia.     

Retinoids and spermatogenesis: lessons from mutant mice lacking the plasma retinol binding protein.

Using Rbp4-null mice as models, we have established for the first time the kinetics of the spermatogenetic alterations during vitamin A deficiency (VAD). Our data demonstrate that the VAD-induced testicular degeneration arises through the normal maturation of germ cells in a context of spermatogonia differentiation arrest. They indicate that retinoic acid (RA) appears dispensable for the transition of premeiotic to meiotic spermatocytes, meiosis, and spermiogenesis. They confirm that RA plays critical roles in controlling spermatogonia differentiation, spermatid adhesion to Sertoli cells, and spermiation, and suggest that the VAD-induced arrest of spermatogonia differentiation results from simultaneous blocks in RA-dependent events mediated by RA receptor gamma (RARgamma) in spermatogonia and by RARalpha in Sertoli cells. They also provide evidence that expression of major RA-metabolizing enzymes is increased in mouse Sertoli cells upon VAD and that vitamin A-deficient A spermatogonia differ from their RA-sufficient counterparts by the expression of the Stra8 gene.     

Patients with erythrophobia (fear of blushing) show abnormal autonomic regulation in mental stress conditions

OBJECTIVE: The objective of this study was to analyze the autonomic functions of patients with erythrophobia. METHODS: Forty patients with a diagnosis of erythrophobia (female/male ratio 18/22) without any other organic lesions and 20 healthy volunteers (female/male ratio 10/10) were assessed. Clinical evaluation was performed using a modified version of semistructured interviews. Autonomic testing was performed by means of spectral analysis of heart rate and continuous blood pressure by sparse discrete Fourier transformation at rest and under mental stress. RESULTS: There were no significant difference between the two samples in age, sex distribution, BMI, resting systolic, or diastolic blood pressure, nor was there a difference in autonomic baseline functioning between the 40 patients with erythrophobia and the control subjects. On the other hand, patients with erythrophobia consistently showed higher pulse rates (88 +/- 20 vs. 78 +/- 9 bpm, p <.05), higher total heart rate power values (8.40 +/- 0.63 vs. 8.07 +/- 1.02 p <.05), higher midfrequency spectral values (7.38 +/- 0.66 vs. 7.02 +/- 1.18, p <.01), higher high-frequency spectral values (6.89 +/- 0.86 vs. 6.48 +/- 1.44, p <.05), and lower baroreceptor sensitivity (8.62 +/- 8.16 vs. 11.65 +/- 4.42, p <.005) than the healthy subjects. ANOVA showed a significant group interaction (p <.0001) between the samples. CONCLUSIONS: This study provides evidence for abnormal autonomic functioning in patients with erythrophobia when under mental stress.     

Blinded, Externally Controlled Multicenter Evaluation of Light Microscopy and PCR for Detection of Microsporidia in Stool Specimens

The quality parameters for the detection of microsporidia in identical sets of 50 stool samples were determined for six laboratories where technicians used light microscopy and for six laboratories where technicians used PCR. The average overall sensitivities were 67% (89% for patient samples only) for the PCR laboratories and 54% (80% for patient samples only) for the light microscopy laboratories. Specificities were 98 and 95%, respectively. Differences in results were most apparent between the individual laboratories rather than between the two major methods used.