Maternal aggression in Wistar rats: effect of 5-HT2A/2C receptor agonist and antagonist microinjected into the dorsal periaqueductal gray matter and medial septum.

The objective of the present study was to assess the role of the 5-HT2A/2C receptor at two specific brain sites, i.e., the dorsal periaqueductal gray matter (DPAG) and the medial septal (MS) area, in maternal aggressive behavior after the microinjection of either a 5-HT2A/2C receptor agonist or antagonist. Female Wistar rats were microinjected on the 7th postpartum day with the selective agonist alpha-methyl-5-hydroxytryptamine maleate (5-HT2A/2C) or the antagonist 5-HT2A/2C, ketanserin. The agonist was injected into the DPAG at 0.2 (N = 9), 0.5 (N = 10), and 1.0 microg/0.2 microl (N = 9), and the antagonist was injected at 1.0 microg/0.2 microl (N = 9). The agonist was injected into the medial septal area (MS) at 0.2 (N = 9), 0.5 (N = 7), and 1.0 microg/0.2 microl (N = 6) and the antagonist was injected at 1.0 microg/0.2 microl (N = 5). For the control, saline was injected into the DPAG (N = 7) and the MS (N = 12). Both areas are related to aggressive behavior and contain a high density of 5-HT receptors. Non-aggressive behaviors such as horizontal locomotion (walking) and social investigation and aggressive behaviors such as lateral threat (aggressive posture), attacks (frontal and lateral), and biting the intruder were analyzed when a male intruder was placed into the female resident's cage. For each brain area studied, the frequency of the behaviors was compared among the various treatments by analysis of variance. The results showed a decrease in maternal aggressive behavior (number of bites directed at the intruder) after microinjection of the agonist at 0.2 and 1.0 microg/0.2 microl (1.6 +/- 0.7 and 0.9 +/- 0.3) into the DPAG compared to the saline group (5.5 +/- 1.1). There was no dose-response relationship with the agonist. The present findings suggest that the 5-HT2A/2C receptor agonist has an inhibitory effect on maternal aggressive behavior when microinjected into the DPAG and no effect when microinjected into the MS. Ketanserin (1.0 microg/0.2 microl) decreased locomotion when microinjected into the DPAG and MS, but did not affect aggressive behavior. We interpret these findings as evidence for a specific role of 5-HT2A/2C receptors in the DPAG in the inhibition of female aggressive behavior, dissociated from those on motor activity.

Evaluation of commercially available preservatives for laboratory detection of helminths and protozoa in human fecal specimens.

Formalin and mercuric chloride-based low-viscosity polyvinyl alcohol (LV-PVA) are widely used by most diagnostic parasitology laboratories for preservation of helminth eggs and protozoan cysts and trophozoites in fecal specimens. Concerns about the toxicity of formalin and the difficulty of disposal of LV-PVA are powerful incentives to use alternate preservatives. Such alternatives have been marketed by several companies and are often presented as one-vial, non-mercuric chloride fixatives that aim at performing the same role as formalin and PVA combined. We compared five, one-vial commercial preservatives, two from Meridian Diagnostics, Inc. (Ecofix and sodium acetate-acetic acid-formalin), and one each from Scientific Device Laboratories, Inc. (Parasafe), Alpha Tec Systems, Inc. (Proto-fix), and Streck Laboratories, Inc. (STF), with 10% formalin and LV-PVA. Fecal specimens obtained from patients in a Brazilian hospital were aliquoted within 12 h of collection into the seven preservatives mentioned above and were processed after 1 month at the Centers for Disease Control and Prevention. Direct and concentrated permanent smears as well as concentrates for 20 positive specimens (a total of 259 processed samples) were prepared, stained according to the manufacturers' instructions, examined, and graded. Positive specimens contained one or more parasites with stages consisting of eggs, larvae, cysts, and a few trophozoites of Giardia intestinalis. Criteria for assessment of the preservatives included the quality of the diagnostic characteristics of helminth eggs, protozoan cysts, and trophozoites, ease of use, and cost. Acceptable alternatives to formalin for wet preparations were found. Ecofix was found to be comparable to the traditional "gold standard" LV-PVA for the visualization of protozoa in permanent stained smears. This study suggests that more acceptable alternatives to the traditional formalin and LV-PVA exist.

[IQ in hydrocephalus and myelomeningocele. Implications of surgical treatment]. / QI em pacientes com hidrocefalia e mielomeningocele. Implicações do tratamento cirúrgico.

Myelomeningocele occurs in 0.4 for 1000 neonates and is associated with hydrocephalus in 85-90%, and reports on cognition are sparsely found in literature. Forty five children with treated hydrocephalus and myelomeningocele were studied in regard of IQ, and statistically correlated to functional motor level, age of the first shunt, number of revisions of shunt, infection of the shunt and circumference of the head. The medium age was of 7.5 years (3-15 years), 16 males and 29 females. Three (6.6%) had a IQ score > 110, 11 (24.4%) had a score between 100-110, 8 between 85-100 (17.7%), 16 (35.5%) between 85-100 (17.7%) and 7 (15.5%) between 50-70. IQ directly correlated with motor level, having better cognitive results the children with minor functional motor disabilities. Cognition was best in children operated until the seven day of life (t 0.0099), with progressive worse results in children operated after the first month of life, no significance was observed in children operated in the period 7 to 31 days (t 0.1013). Worse results were observed in the group of patients with infection of shunts (t 0.0146). Results were progressively worse with reoperations. The best results in relation of the circumference of the head were seen with children in the medium range (t 0.0115); intermediate results were seen in patients between the medium range and-1SD (t 0.00130) and medium range and +1SD. The worse results were seen in patients at the extremes of > 1SD (t 0.0269) and < ISD (t 0.0042). According to cognitive results the surgical treatment of hydrocephalus have to be done until the first month of life, avoiding reoperations and infections that have unfavorable impact in IQ.

Differential expression of an hsp70 gene during transition from the mycelial to the infective yeast form of the human pathogenic fungus Paracoccidioides brasiliensis.

We have isolated and characterized cDNA and genomic clones that encode a 70 kDa heat shock protein (Hsp70) from the dimorphic human pathogenic fungus Paracoccidioides brasiliensis. The gene encodes a 649-amino-acid protein showing high identity with other members of the hsp70 gene family. The hsp70 gene is induced during both heat shock of yeast cells at 42 degrees C and the mycelial to yeast transition. A differential expression of this gene can be observed between mycelial and yeast forms, with a much higher level of expression in the yeast. We found two introns of 178 and 72 nucleotides in the P. brasiliensis hsp70 gene. Splicing of these introns is regulated during the heat shock process and possibly during infection. In order to analyse the differential accumulation of unspliced mRNA following cellular differentiation and/or heat shock, reverse transcriptase-polymerase chain reaction (RT-PCR) experiments were carried out. The temperature-induced mycelial to yeast transition results in the transient accumulation of unspliced hsp70 mRNA transcripts. Yeast cells, after adaptation at 36 degrees C, seem to be more proficient at splicing, at least with respect to hsp70 mRNA because, during a severe heat shock (42 degrees C), the unspliced form of this mRNA does not accumulate. The mycelial to yeast differentiation will have the adaptational effect of increasing the resistance of the organism to environmental stress, which may be necessary for parasite survival in the mammalian host.

Characterization of Paracoccidioides brasiliensis isolates by random amplified polymorphic DNA analysis.

We initially used 25 different random primers in order to test their ability to generate random amplified polymorphic DNA fragments from the dimorphic human pathogenic fungus Paracoccidioides brasiliensis. From the tested primers we chose five to distinguish between seven isolates of this microorganism. The DNA amplification patterns allowed clear differentiation of the seven isolates into two distinct groups with only 35% genomic identity. One of these groups contained two subgroups with 81% genetic similarity. The random amplified polymorphic DNA analysis method proved to be a good tool for analyzing and comparing different genomes of P. brasiliensis isolates.

Time course of the effect of praziquantel on Schistosoma mansoni attachment in vitro: comparison with its effects on worm length and motility.

We report herein that praziquantel inhibits the capacity of adult male Schistosoma mansoni to attach to the bottom of a glass dish and produces a diminution of worm length and motility, acting under a similar concentration and time dependency. After removal of 1 microM praziquantel from the medium, the worms progressively recuperated their initial length and motility without recovering their attachment capability. The absence of calcium or presence of 1 microM verapamil did not change the praziquantel-induced effect on worm attachment, causing only a transient decrease in worm length and motility. The present data indicate that the diminution of motility induced by praziquantel results from the progressive contraction of the longitudinal musculature of the worm. In contrast, the loss of attachment should not be causally related to the contraction of the worm since these two praziquantel-induced effects have distinct patterns of response under some experimental conditions.

Ischaemic colitis (necrotizing colitis, pseudomembranous colitis) in acute schistosomiasis mansoni: report of two cases.

Two cases of ischaemic necrosis of the sigmoid colon (necrotizing colitis) are reported in 2 brothers aged 7 and 4 years, diagnosed within a 10 d interval. The children had bathed in streams suspected to be contaminated by Schistosoma mansoni about 50-60 d before the onset of acute disease. Both patients had been previously exposed to schistosome-infected streams without showing signs or symptoms of infection. Before admission, S. mansoni eggs had not been found in the stool. Both patients presented with an apparently identical, relatively symptomatic clinical course with rapid evolution to an acute abdomen. Laparotomy disclosed, in both patients, extensive necrosis (ischaemic necrotizing colitis of schistosomal aetiology) of about 20 cm in the first child and 8 cm in the second, extending from part of the descending colon to the sigmoid. The patients were successfully operated upon (hemicolectomy plus colostomy). The histopathological findings were similar in both patients. Ischaemic necrosis with complete destruction of the mucosa and part of the submucosa was detected in the first case; in the necrotic areas a few eggs of S. mansoni were seen, with no granulomatous reaction, but surrounded by cell shadows, pycnotic nuclei and amorphous material. Necrosis extended to the muscular layer and serosa, in which schistosome granulomas in the necrotic-exudative phase were seen, as well as diffuse granulocytic exudate and fibrin. Sections of tissue from both patients contained numerous eggs and granulomas all in the same exudative phase in regional lymph nodes and near the thrombotic vessels. After surgery, the 2 patients progressed similarly. About 10 d after hospital discharge, the patients received anti-schistosomal treatment with oxamniquine. No further sign of infection was detected at subsequent recall visits.

Praziquantel inhibits Schistosoma mansoni attachment in vitro.

Male adult Schistosoma mansoni worms were placed in a glass dish containing Tyrode solution and observed for 15 min after addition of praziquantel (0.01 to 1 microM). Praziquantel promoted a concentration- and time-dependent inhibition of sucker-mediated attachment of the worm. Attachment inhibition was correlated with shortening of the parasite. We propose that the rapid and total inhibition of worm attachment observed in vitro with 1 microM praziquantel indicates that therapeutic concentrations of this drug should promote a rapid hepatic shift, in vivo, which may facilitate host tissue reaction.