Apolipoprotein B polymorphism and altered apolipoprotein B concentrations in Congolese blacks

The immunoreactivity of apolipoprotein B (apo B) in plasma obtained from 238 unrelated black African male subjects from the People's Republic of Congo was analysed by non-competitive Enzyme Linked-Immunosorbent Assay (ELISA) with monoclonal BIP 45 anti-LDL antibody. The polymorphism detected by BIP 45 monoclonal antibody is identical to the Ag(c,g) polymorphism. Antibody BIP 45 distinguishes three apo B allotypes (immunophenotypes) encoded by the two allelic genes apo B Ag(c) and apo B Ag(g). Because of co-dominant transmission, genotypes may be inferred from allotypes, and it has been shown that BIP 45 binds strongly to the Ag(c) factor and only weakly to the allelic Ag(g) factor. Analysis of the Congolese plasma samples indicated that 67.65% of them bound BIP 45 with low affinity (Ag(c-,g+) genotype), 28.15% with intermediate affinity (Ag(c+,g+) genotype) and 4.20% with high affinity (Ag(c+,g-) genotype). According to the Hardy-Weinberg equilibrium, this corresponds to gene frequencies of 0.817 and 0.183 for the type Ag(g)/Ag(c) alleles, respectively. After adjustment for age and body-mass index, it was found that the Ag(c) allele decreases the apo B level by 9.62 mg/dl and that the Ag(g) allele increases apo B by 0.43 mg/dl. Therefore, as much as 4.30% of the genetic variance for apo B level could be accounted for by the Ag(c,g) gene locus.     

Paraxanthine displaces the binding of [3H]SCH 23390 from rat striatal membranes

We present evidence showing that paraxanthine (1,7-dimethylxanthine), the main metabolite of caffeine in man, displaces the binding of [3H]SCH 23390, a radioligand which selectively labels dopamine D-1 receptors when used at low concentrations, from striatal membranes of the rat. The displacement was competitive and indicated the existence of two affinity states (Hill coefficient = 0.49; K(high) = 0.15 microM; K(low) = 95.9 microM, %R(high) = 32.4). When the stable GTP analog Gpp(NH)p was included, the displacement curve indicated the presence of only the low-affinity state (Hill coefficient = 1.16; Ki = 72.1 microM). However, paraxanthine did not displace the specific binding of [3H]spiperone. After injection of 30 mg/kg s.c. of caffeine, a maximum of 10 microM of paraxanthine was found in striatal homogenates, which could be sufficient to occupy dopamine D-1 receptors. Our results suggest that a dopaminergic action of paraxanthine could be involved in the behavioural stimulation produced by caffeine.     

INVASIVE MUCORMYCOSIS WITH GASTRIC INVOLVEMENT IN A PATIENT WITH SEVERE ATHEROMATOUS VASCULAR DISEASE

Gastric mucormycosis involvement is a rare condition that usually occurs in inmunocompromised patients and frequently has a fatal outcome. We report the case of a 73‐year‐old woman admitted to the intensive care unit with severe bleeding after an acute pulmonary disease. Upper endoscopy disclosed wide and deep necrotic ulcers in the body and fundus of the stomach and greenish exudates with the antrum and the duodenum undamaged. Autopsy revealed an invasive mucormycosis and a severe atheromatosis. Several predisposing factors for mucormycosis infection have been reported until now. We postulate that ischemic gastritis could be a predisposing factor for colonization of zygomycete.     

Nutritional Aspects of Breath Testing Based on Stable Isotopes

Stable isotope methodologies offer a number of possibilities for the nutritional assessment of many different processes and metabolic pathways. The application of stable isotopes has been boosted by the development of new mass spectrometers, lower costs of probes, and the risks associated with radioactive tracers. The use of ¹³C as a tracer offers all the advantages of stable isotopes and has been widely applied for measuring various types of metabolic processes. This review is focused on clinical and nutritional assessments using ¹³C breath tests.     

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.     

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.