Antigenic variation in rabies and rabies-related viruses: cross-protection independent of glycoprotein-mediated virus-neutralizing antibody

Immunization experiments with vaccines prepared from the PM and ERA strains of rabies virus demonstrated that in mice, only ERA vaccine primes for an anamnestic response to the rabies-related strain Duvenhage (DUV6); in rabbits, both ERA and PM vaccines induced immunologic memory to DUV6 virus. In mice, ERA vaccine, but not an equal concentration of PM vaccine, conferred protection against a lethal challenge infection with DUV6 virus. This result indicated that the protective activity correlated with the vaccine's ability to induce immunologic memory. A vaccine prepared from a sequentially selected, neutralization-resistant, multiple-variant virus conferred protection against challenge with the parental strain, a result indicating that antigenic variation of the glycoprotein may not be the sole factor in determining the relative efficacy of rabies prophylaxis. We found no correlation between titers of neutralizing antibody and mortality rates in mice immunized with purified glycoprotein from these viruses.     

Evaluation of Lama glama semen viscosity with a cone-plate rotational viscometer

Llama semen is highly viscous. This characteristic is usually evaluated subjectively by measuring the thread formed when carefully pippeting a sample of semen. The aims of this study were (i) to objectively determine and analyse llama semen viscosity, (ii) to compare semen viscosity between ejaculates of the same male as well as between different males, (iii) to study the correlation between viscosity and other semen characteristics and (iv) to evaluate the effect of collagenase on semen viscosity. Semen viscosity was evaluated using a cone-plate Brookfield rotational viscometer. A non Newtonian, pseudoplastic behaviour was observed in the 45 semen samples evaluated. Rheological parameters were determined obtaining the following results (mean ± SD): apparent viscosity at 11.5 s(-1): 46.71 ± 26.8 cpoise and at 115 s(-1): 12.61 ± 4.1 cpoise; structural viscosity (K) (dyne s cm(-2)): 2.18 ± 1.4 and coefficient of consistency (n): 0.45 ± 0.1. Statistical differences were found between different ejaculates of the same male for structural viscosity and apparent viscosity at 11.5 s(-1) (P < 0.01). Correlation was found only between coefficient of consistency (n) and sperm concentration (P < 0.01). Significant differences for coefficient of consistency (n) and viscosity at 115 s(-1) were found between samples incubated with and without collagenase (P < 0.05).     

ER stress regulates myeloid-derived suppressor cell fate through TRAIL-R–mediated apoptosis

Myeloid-derived suppressor cells (MDSCs) dampen the immune response thorough inhibition of T cell activation and proliferation and often are expanded in pathological conditions. Here, we studied the fate of MDSCs in cancer. Unexpectedly, MDSCs had lower viability and a shorter half-life in tumor-bearing mice compared with neutrophils and monocytes. The reduction of MDSC viability was due to increased apoptosis, which was mediated by increased expression of TNF-related apoptosis–induced ligand receptors (TRAIL-Rs) in these cells. Targeting TRAIL-Rs in naive mice did not affect myeloid cell populations, but it dramatically reduced the presence of MDSCs and improved immune responses in tumor-bearing mice. Treatment of myeloid cells with proinflammatory cytokines did not affect TRAIL-R expression; however, induction of ER stress in myeloid cells recapitulated changes in TRAIL-R expression observed in tumor-bearing hosts. The ER stress response was detected in MDSCs isolated from cancer patients and tumor-bearing mice, but not in control neutrophils or monocytes, and blockade of ER stress abrogated tumor-associated changes in TRAIL-Rs. Together, these data indicate that MDSC pathophysiology is linked to ER stress, which shortens the lifespan of these cells in the periphery and promotes expansion in BM. Furthermore, TRAIL-Rs can be considered as potential targets for selectively inhibiting MDSCs.     

A classification of dental composites according to their morphological and mechanical characteristics.

The on-going search for a biologically acceptable restorative material has brought a confusing variety of composites on the dental market. In the present study, commercially available composites are categorized as a function of their mean particle size, filler distribution, filler content, Young's modulus, surface roughness, compressive strength, surface hardness, and filler morphology. Out of this information, it can be concluded that the materials of choice for restoring posterior cavities at present are the Ultrafine Compact-Filled Composites because their intrinsic surface roughness, Young's modulus and, indirectly, their filler content, compressive strength, and surface hardness are comparable to the same properties of enamel and dentin. The Ultrafine Midway-Filled Composites seem to be very satisfactory materials for anterior use.     

Differences in the release of melanocyte-stimulating hormone in vitro by rat pituitary glands collected at various times during the oestrous cycle

The release of melanocyte-stimulating hormone (MSH) into the medium during incubation and the pituitary tissue content of MSH were measured separately using pituitary glands collected from rats at various stages of the oestrous cycle. The MSH was measured by a biological assay using a synthetic alpha-MSH as standard. The release of MSH was maximal during thepro-oestrous phase and MSH content of the pituitary gland was highest during dioestrus. The influences of the tripeptide Pro-Leu-Gly-NH2, which inhibits MSH secretion in vivo, and of progesterone on the release of MSH in vitro were studied with tissue collected at various phases of the oestrous cycle. Pro-Leu-Gly-NH2 was effective in inhibiting MSH release both at pro-oestrus and oestrus but not at dioestrus. Progesterone overcame this inhibition.     

Risk factors and incidence of posttransplant diabetes mellitus in Mexican kidney recipients

BACKGROUND: Many risk factors are associated with the development of posttransplant diabetes mellitus (PTDM), which has adverse effects on graft and patient survival. We report the incidence and risk factors associated with the development of PTDM in Mexican kidney recipients. METHODS: In a retrospective cohort study, we included kidney transplants performed between January 1, 1994 and December 31, 2000; all patients were followed up for at least 1 year posttransplantation. PTDM was defined as fasting blood glucose >126 mg/dL on at least two occasions. Statistical analysis included estimation of crude relative risk (RR) with 95% confidence intervals (CI). Adjusted RR and 95% CI by logistic regression were used. RESULTS: We studied 522 kidney recipients. Fifty three (10.1%) cases of PTDM were identified in this cohort. Cumulative dosage of prednisone (PDN) >13 g (RR 7.6, 95% CI 1.5-16.3 p <0.0001) and the presence of >or=1 acute rejection episodes (RR 3.7, 95% CI 1.2-11.6 p <0.001 were independent risk factors associated with the development of PTDM. Obesity (RR 2.6, 95% CI 0.8-8.7, p = 0.083) and age range of 40-49 years (RR 2.0; 95% CI 0.6-7.2, p = 0.093) were identified as marginal risk factors. CONCLUSIONS: The incidence of PTDM in kidney recipients was 10.1% in our population. Cumulative PDN dosage and presence of >or=1 acute rejection episodes were independent risk factors for the development of PTDM. These results are consistent with prior studies of the diabetogenic effect of the PDN. The relationship between acute rejection and PTDM deserves further investigation in order to learn more about the role that inflammatory mechanisms may play in this association.