TCRBV3S1 and TCRBV18 gene segment polymorphisms in Brazilian Caucasoid and Black populations.

The T-cell receptor (TCR) repertoire plays an important role in shaping specific immune responses. Genetic polymorphisms at the TCR locus, in both constant and variable regions, seem to represent an important mechanism for generating inter-individual and inter-population differences. Considering the scarcity of immune parameters characterized for normal human populations, we decided to determine the frequency of two TCRBV polymorphisms (located in the TCRBV3S1 and TCRBV18 gene segments) in two ethnically distinct groups of the general Brazilian population. Both polymorphisms are related to the expression of these segments at the T-cell surface and can consequently modulate the T-cell repertoire, potentially modifying the capacity of a given individual to develop an immune response. These DNA polymorphisms were analysed in material obtained from adult, normal South-American Caucasoid and Black individuals. A total of 139 individuals were analysed for the TCRBV3S1 and 141 for the TCRBV18 gene segment polymorphisms. The data indicated statistically significant differences in allelic frequencies for the two ethnic groups analysed, suggesting that any correlation between TCR usage or T-cell repertoire and development of a given disease should take in account the ethnic origin of the population studied.     

Advantages of topical marcaine during spinal surgery. Technical note

Marcaine applied to irritated nerve roots during extradural spinal surgery may attenuate sympathetically mediated and somatosensory (pain)-related hypertensive and tachycardic crises.     

Dietary L-lysine and calcium metabolism in humans.

Calcium deficiency contributes to age-related bone loss; consequently, any preventive approach to osteoporosis should include dietary Ca adjustment or supplementation. The ideal Ca supplement would yield the greatest bioavailability. Studies in animals have shown that dietary supplements with certain amino acids, particularly L-lysine, can increase Ca absorption. Therefore, we examined the potential effect of this essential amino acid on Ca metabolism in humans. In one study, the acute effects of an oral Ca load (3 g as CaCl2) administered with or without 400 mg of L-lysine were compared in 15 healthy and 15 osteoporotic women. In all cases, the oral Ca load determined a progressive increase in serum total Ca and Ca2+ and a concomitant decrease in neophrogenous cAMP. As expected, a progressive increase in urinary Ca excretion was also observed, except in the L-lysine-treated healthy subjects, who exhibited a blunted calciuric response to the Ca load. In a second study, the effects of a short-term dietary supplementation with either L-lysine, L-valine, or L-tryptophan (800 mg/day) on 47Ca fraction absorption were compared in 45 osteoporotic patients. L-Lysine but not L-valine or L-tryptophan significantly increased the intestinal absorption of the mineral. Our results suggest that L-lysine can both enhance intestinal Ca absorption and improve the renal conservation of the absorbed Ca. The combined effects may contribute to a positive Ca balance, thus suggesting a potential usefulness of L-lysine supplements for both preventive and therapeutic interventions in osteoporosis.     

Changes in microtubule-associated protein-2 (MAP2) expression during development and after status epilepticus in the immature rat hippocampus

In this study, we analyzed the spatiotemporal expression patterns of the high-molecular weight (MAP2a and b) and low-molecular weight (MAP2c and d) cytoskeletal microtubule-associated protein-2 (MAP2) isoforms with Western blotting, and the cellular localization of the high-molecular weight MAP2 isoforms with immunocytochemistry in the hippocampi of 1- to 21-day-old rats. Moreover, the temporal profile (from 30 min to 1 week) of MAP2 isoform reactivity to kainic acid-induced status epilepticus was studied in P9 rats. During development, the expression of the high-molecular weight MAP2 isoforms significantly increased, while the low-molecular weight isoforms decreased, the most prominent changes occurring during the second postnatal week. This developmental increase in the high-molecular weight MAP2 expression was also confirmed with immunocytochemistry, which showed increased immunoreactivity, particularly in the molecular layers of the dentate gyrus, and in CA1 and CA3 stratum radiatum. In 9-day-old rats, status epilepticus resulted in a rapid transient increase (about 210%) in the high-molecular weight MAP2 expression, without any effect on the low-molecular weight MAP2. Moreover, disturbed dendritic structure in the CA1 and CA3 stratum radiatum was manifested as formation of varicosities 3h after the kainic acid treatment. The strictly developmentally regulated MAP2 isoform expression suggests different functional roles for these proteins during the postnatal development in the rat hippocampus. Moreover, high-molecular weight MAP2s may play a role in nerve cell survival during cell stress.     

Topical application of isosorbide dinitrate in patients with persistent constipation after pull-through surgery for Hirschsprung's disease.

AIMS: The aim of this study was to evaluate the anal manometric changes and the clinical effects after topical application of isosorbide dinitrate (ISDN) in patients with persistent constipation after pull-through surgery for Hirschsprung's disease (HD). METHODS: We studied 3 children (2 males and 1 female), aged 2, 3 and 5 years respectively, who had undergone the Soave-Boley surgical procedure for HD and who suffered from persistent constipation after operation. We performed a pre- and postoperative anorectal manometry study and we applied ISDN paste (1 mg/kg two times daily) in the anal region for three weeks. All patients were followed-up and re-evaluated at 1, 3, and 6 months. RESULTS: All patients showed an improvement of symptoms, with an average of 4 spontaneous evacuations per week. Prior to the topical treatment, the medium pressure was 115.6 mmHg (range 102 - 130 mmHg), the maximum pressure was 160 mmHg (range 145 - 175 mmHg), and the medium length of the high pressure zone was 1.8 cm (range 1.5 - 2.0 cm). At the 6 month follow-up, the medium pressure was 57.3 mmHg (range 52 - 61 mmHg, a decrease of 54.4 %), the maximum pressure was 98 mmHg (range 88 - 107 mmHg; a decrease of 38.7 %), and the medium length of the high pressure zone was 1.6 cm (range 1.4 - 1.8 cm; a decrease of 11.1 %). CONCLUSIONS: Topical treatment with ISDN is a valid therapeutic alternative to an anal myotomy in patients with persistent constipation after pull-through surgery for HD. However, a greater number of cases and a longer follow-up are necessary to confirm the validity of our experience.     

Symptomatic cystic dilatation of V ventricle: Case report and review of the literature

We report a case of V ventricular cystic dilatation, presenting with specific neurological symptoms including low back pain, bilateral sciatica, weakness of dorsiflexion, and urinary retention. MRI showed a large cystic dilatation of the ventriculus terminalis. Surgical fenestration of the cyst allowed complete relief from symptoms and remission of the neurological deficit.     

Alterations in the ultrastructure of cardiac autonomic nervous system triggered by crotoxin from rattlesnake (Crotalus durissus cumanensis) venom.

This study explored the toxic effects of crotoxin isolated from Crotalus durissus cumanensis venom on the ultrastructure of mice cardiac autonomic nervous system. Mice were intravenously injected with saline (control group) and crotoxin diluted in saline venom (study group) at a dose of 0.107 mg/kg mouse body weight. Samples from the inter-ventricular septum were prepared for electron microscopy after 6 h (G1), 12 h (G2), 24 h (G3) and 48 h (G4). The G1 group showed some cardiomyocyte with pleomorphic mitochondria. Capillary swollen walls, nerve cholinergic endings with depleted acetylcholine vesicles in their interior and other depletions were observed. A space completely lacking in contractile elements was noticed. The G2 group demonstrated a myelinic figure, a subsarcolemic region with few myofibrils and nervous cholinergic terminal with scarce vacuoles in their interior. The G3 group demonstrated a structure with a depleted axonic terminal, mitochondrias varying in size and enhanced electron density. In addition, muscular fibers with myofibrillar structure disorganization, a depleted nervous structure surrounded by a Schwann cell along with an abundance of natriuretic peptides, were seen. An amyelinic terminal with depleted Schwann cell and with scarce vesicles was also observed. Finally, axonic lysis with autophagic vacuoles in their interior and condensed mitochondria was observed in the G4 group. This work describes the first report of ultrastructural damage caused by crotoxin on mice cardiac autonomic nervous system.