Morpho-anatomical characterization of mature embryo-derived callus of rice (Oryza sativa L.) suitable for transformation.

The objective of this study was to morpho-anatomically characterize embryogenic rice calli during early induction of somatic embryogenesis of three Brazilian rice cultivars. Herein, we explored embryogenic units (EUs) from 2-week-old cut proliferated calli to verify whether they were suitable for Agrobacterium tumefasciens-mediated transformation. Histological analysis and scanning electron microscopy (SEM) were used to analyze these types of calli during early rice callogenesis in the cultivars BRS Primavera, BRS Bonança, and BRS Caiapó. The characteristics of the embryogenic cells were preserved in the EUs, which showed a globular, compact structure that contained tightly packed cells and thus rendered the cells suitable for transformation. The EUs of BRS Caiapó also maintained the characteristics of the non-embryogenic callus, such as an elongated morphology and a lack of cellular organization. In general, the observations of the histological sections corresponded with those of the SEM images. The histological analysis suggested that all cultivars used in these experiments have morphogenic potential. The EUs from proliferated 2-week-old cut calli maintained their embryogenic features. The EUs were subjected to Agrobacterium-mediated transformation, which exhibited a regeneration frequency of 58 % for transformed hygromycin-resistant cell lines. These results show that EUs from proliferated 2-week-old cut calli are suitable for plant transformation.

Digestion, absorption and tissue distribution of ovalbumin and palmitoyl-ovalbumin: impact on immune responses triggered by orally administered antigens.

Previous work in this laboratory has demonstrated that ovalbumin coupled to palmitoyl residues (palmitoyl-Ova) does not induce oral tolerance. The present study sought to determine whether this coupling affects digestion, absorption and transfer of antigen. Ova and palmitoyl-Ova were shown to be digested differently in vitro by proteolytic enzymes and presented different tissue distribution kinetics after being labelled with (99m)technetium and orally administered to animals. Palmitoyl-Ova remained longer in the stomach, while native Ova was quickly transferred to the gut and other organs. After 3 h, higher levels of palmitoyl-Ova were found in the blood, Peyer's patches, mesenteric lymph nodes, liver and, especially, the spleen, which appears to be essential for immunization with palmitoyl-Ova. In fact, splenectomized mice treated orally with palmitoyl-Ova became tolerant, while tolerance to Ova was not affected. Thus, palmitoyl coupling was demonstrated to affect antigen digestion, absorption and transport. This is the first time that the spleen has been shown to be required for oral immunization with palmitoyl-Ova.

Perception of vulnerability to HIV infection in a cohort of homosexual/bisexual men in Rio de Janeiro, Brazil. Oswaldo Cruz Foundation STD/HIV Prevention Group.

The present study addresses sociodemographic characteristics, knowledge and attitudes regarding HIV/AIDS, as well as risk behaviour and perception of vulnerability to HIV infection, in the first 295 homosexual and bisexual volunteers (excluding male commercial sex workers and transvestites) taking part in a cohort study in Rio de Janeiro. The sample has a higher socio-economic level than the remainder of the cohort, and than comparable strata of the general population, and a sound knowledge about how to protect themselves against HIV infection. In addition, an association between perception of vulnerability to infection and the practice of unprotected anal sex was observed. An association was also observed between higher levels of formal education and perception of vulnerability; however no association was found with markers for past and recent exposure to sexually transmitted infections (hepatitis B, HbsAG and syphilis). The results of the present study suggest that knowledge and awareness of risk do not easily translate into behaviour change, since significant proportions of the cohort continue to practise unprotected sex with both principal and casual partners, despite their awareness of HIV infection risks as well as preventive measures.

[Acute facial pain associated with mandibular motion damage: considerations on a clinical sample]. / Dor facial aguda associada a alteração motora mandibular: considerações sobre uma amostra clínica.

The authors present a sample of five patients, 3 women and 2 men, with history of the dislocation of the mandible. The period ranged between 7 days and 7 months and all the patients looked for medical treatment, but did not have a correct diagnostic. The initial diagnostic was tetanus, sequela for VCA, food intoxication. The younger patient was 23 years old and the older was 63 years old. The first male patient was 23 years old and his first complaint was facial pain, rigidity, difficulty in speaking, chewing and the diagnosis received was Tetan, after 7 days. The second female patient was 61 years old and her first complaint was difficulty in speaking and chewing. The diagnosis was food intoxication after 7 month. The third patient was 54 years old. The first complaint was idiopathic, after 1 month. He did'nt managed to shut up his mouth--diagnosis idiopathic cause. The fourth patient was 63 years old and his first complaint was assimetric and facial pain due a neurological remains, after 4 month. And finally the fifth patient. He was 56 years old and the first complaint was an intense difficulty in speaking and shut out his mouth--hemiplegia in the left face due neurological remain, after 3 month. The authors make a review about the criteria for a diagnosis of dislocation of mandible and the benefits of immediate treatment.