Immunity in the absence of CD28 and CD137 (4-1BB) molecules

We report the generation and immune regulation of mice that are deficient in CD28 and 4-1BB (CD137) genes. These mice were viable, fertile and did not display any overt abnormalities and had a normal T cell phenotype in thymus and spleen. Proliferative responses to anti-CD3 and ConA were enhanced in 4-1BB-/- but not in either CD28-/- or double mutant mice, while levels of interleukin-2 were decreased in all mutant mice. Although the 4-1BB-/- mice displayed increased basal levels of most immunoglobulin isotypes tested, the plateau levels of immunoglobulin G2a, immunoglobulin G2b and immunoglobulin A were particularly high compared to wild type controls. The immunoglobulin class switch to T-dependent antigen was normal in 4-1BB-/- mice but was greatly affected in both CD28-/- and 4-1BB-/- CD28-/- mice. Vesicular stomatitis virus-specific cytotoxic T lymphocyte responses and plaque reduction neutralizing ability was differentially reduced in all mutant mice. Contact sensitivity to allergens showed marginal but not significant change in ear thickness in 4-1BB-/- mice, but an ability to mount contact hypersensitivity to the same antigens was greatly curtailed in CD28-/- and double mutant mice.     

Paracetamol and conventional antimalarial drugs induced hepatotoxicity and its protection by methionine in rats

Hepatotoxicity, induced in rats, by treatment with high doses of paracetamol and chloroquine was confirmed by estimating blood transaminase levels. Hepatoprotective effect was determined by administering combination of methionine (10% of paracetamol/chloroquine, p.o.) and hepatotoxic drugs quinine. The results were confirmed by histopathological examination of liver. Paracetamol (7 g/kg) and chloroquine (970 mg/kg) administration increased significantly the transaminase levels. Methionine alone did not produced any change. Hepatonecrosis induced by paracetamol, chloroquine alone and their combinations and its protection with methionine was revealed by histopathological study whereas the combination of paracetamol and methionine showed no significant histopathological difference when compared to the normal liver section. The results reveal that, methionine significantly prevented the rise in transaminases levels produced by hepatotoxic doses of paracetamol and chloroquine. But, to prevent occasional cases of paracetamol overdosage, it is not advisable to give methionine concurrently with paracetamol to patients who are taking paracetamol therapeutically.     

Nuclear gene trees and the phylogenetic relationships of the mangabeys (Primates: Papionini)

Phylogenetic relationships of mangabeys within the Old World monkey tribe Papionini are inferred from analyses of nuclear DNA sequences from five unlinked loci. The following conclusions are strongly supported, based on congruence among trees derived for the five separate gene regions: (1) mangabeys are polyphyletic within the Papionini; (2) Cercocebus is the sister taxon to the genus Mandrillus; and (3) Lophocebus belongs to a clade with Papio and Theropithecus, with Papio as its most likely sister taxon. Morphologically based phylogenies positing mangabey monophyly were evaluated by mapping the sequences for each locus on these trees. The data seem to fit these trees poorly in both maximum-parsimony and likelihood analyses. Incongruence among nuclear gene trees occurred in the interrelationships among Lophocebus, Papio, and Theropithecus. Several factors that may account for this incongruence are discussed, including sampling error, random lineage sorting, and introgression.      

Active coping toward predatory stress is associated with lower corticosterone and progesterone plasma levels and decreased methylation in the medial amygdala vasopressin system

An active coping style displayed under stress – which involves proactive investigatory responses toward environmental threats – has been associated with reduced vulnerability to psychiatric illness. However, the neurobiological determinants of coping styles are not well understood. When rats are exposed to a naturalistic stressor (cat fur) in a group, some individuals in the group show robust active investigation of the stimulus while others show a passive response involving retreat, immobility and close aggregation with conspecifics. Here we explored endocrine and epigenetic correlates of these contrasting coping styles. Male Wistar rats (n = 48) were exposed to cat fur in groups of 4 and the passive and active responders were identified and assessed for endocrine and epigenetic differences. Three days after the final cat fur exposure, active responders had substantially lower plasma levels of corticosterone and progesterone than passive responders. Plasma and testicular testosterone levels did not differ between active and passive responders. Active responders had markedly less methylation of the AVP CGCG promoter region located at base 4970 in the posterodorsal region of the medial amygdala but did not differ in the methylation status of the CCGG sequence located at base 2243. This is in agreement with prior research suggesting that AVP and progesterone act in opposition within the medial amygdala to modulate stress-related behaviors. The present study reports striking endocrine and epigenetic differences between active and passive responders, providing insight into potential systems involved in the manifestation of differing coping styles.     

The urokinase plasminogen activator receptor as a gene therapy target for cancer

Urokinase plasminogen activator (uPA) and/or its receptor (uPAR) are essential for metastasis, and overexpression of these molecules is strongly correlated with poor prognosis in a variety of malignant tumours. Impairment of uPA and/or uPAR function, or inhibition of the expression of these components, impedes the metastatic potential of many tumours. Several approaches have been employed to target uPAR with the aim of disrupting its ligand-independent action or interaction with uPA, including the more recent antigene technology. This review discusses the in vivo use of antigene approaches for downregulating uPAR as a potential therapy for cancer. Preclinical studies are advancing towards the translational phase, provided that established orthotopic tumours, which mimic clinical progression and presentation, are treated using clinically acceptable modes of nucleic acid delivery.     

Systematic variation in mRNA 3'-processing signals during mouse spermatogenesis

Gene expression and processing during mouse male germ cell maturation (spermatogenesis) is highly specialized. Previous reports have suggested that there is a high incidence of alternative 3′-processing in male germ cell mRNAs, including reduced usage of the canonical polyadenylation signal, AAUAAA. We used EST libraries generated from mouse testicular cells to identify 3′-processing sites used at various stages of spermatogenesis (spermatogonia, spermatocytes and round spermatids) and testicular somatic Sertoli cells. We assessed differences in 3′-processing characteristics in the testicular samples, compared to control sets of widely used 3′-processing sites. Using a new method for comparison of degenerate regulatory elements between sequence samples, we identified significant changes in the use of putative 3′-processing regulatory sequence elements in all spermatogenic cell types. In addition, we observed a trend towards truncated 3′-untranslated regions (3′-UTRs), with the most significant differences apparent in round spermatids. In contrast, Sertoli cells displayed a much smaller trend towards 3′-UTR truncation and no significant difference in 3′-processing regulatory sequences. Finally, we identified a number of genes encoding mRNAs that were specifically subject to alternative 3′-processing during meiosis and postmeiotic development. Our results highlight developmental differences in polyadenylation site choice and in the elements that likely control them during spermatogenesis.     

Protozoan parasite Toxoplasma gondii manipulates mate choice in rats by enhancing attractiveness of males

Females in various species typically avoid males infected with parasites, while parasite-free males advertise their status through conspicuous phenotypic traits. This process selects for heritable resistance and reduces direct exposure of the female to parasites. Coevolving parasites are likely to attempt to circumvent this obstacle. In this paper, we demonstrate a case of parasitic manipulation of host mate choice. We report that Toxoplasma gondii, a sexually transmitted infection of brown rats, enhances sexual attractiveness of infected males. Thus under some evolutionary niches, parasites can indeed manipulate host sexual signaling to their own advantage.     

Thermal inactivation of the reductase domain of cytochrome P450 BM3

Although the reductase domain of cytochrome P450 BM3 (BMR) catalyzes the reduction of cytochrome c and 2,6-dichlorophenolindophenol, we observed a catalytically independent loss of activity. By varying the incubation time for the enzyme prior to reaction initiation, we measured an inactivation rate of 0.22 min(-1). We hypothesized that either an active BMR dimer dissociates to an inactive monomer or BMR undergoes denaturation. We were not able to trap or destabilize a dimer, and BMR inactivation proved to be irreversible. Addition of excess FMN only slightly decreased the rate of inactivation from 0.22 to 0.13 min(-1), indicating inactivation likely does not reflect loss of flavin. When inactivation rates as a function of temperature were fit to the Arrhenius equation, the energy required to inactivate BMR was 9.9 kcal mol(-1)--equivalent to a few hydrogen bonds. The potential instability of BMR under certain conditions raises concerns for the use of BMR as a model or surrogate P450 reductase in other systems.     

Effect of zinc supplementation from different sources on growth, nutrient digestibility, blood metabolic profile, and immune response of male guinea pigs

Forty weaned male guinea pigs of 208.20±6.62 g mean body weight were divided into 4 groups of 10 animals in a randomized block design. All of the guinea pigs were fed a basal diet [25% ground maize hay, 30% ground maize grain, 22% ground chickpea (Cicer arietinum L.), 9.5% deoiled rice bran, 6% soybean meal, 6% fish meal, 1.45% mineral supplement (without Zn) and 0.05% ascorbic acid] and available green fodder. Group I served as the control (no Zn supplementation), whereas 20 ppm Zn was added in the diet in groups II, III, and IV either as zinc sulfate (ZnSO₄), zinc amino acid complex (ZAAC), and ZnSO₄ ⁺ ZAAC in equal parts, respectively. Experimental feeding lasted for 70 d, including a 3-d digestibility trial. Blood was collected through cardiac puncture from four animals in each group at d 0 and subsequently at the end of experimental feeding. After 40 d of experimental feeding, four animals from each group were injected with 0.4 mL of Brucella abortus cotton strain-19 vaccine to assess the humoral immune response of the animals. After 10 wk of study, four animals from each group were sacrificed to study the concentration of Zn, Cu, Co, Fe, and Mn in the liver, pancreas and spleen. Results revealed no significant difference in the feed intake, body weight gain, and digestibility of the nutrients, except for crude protein (CP) digestibility, which was significantly (p<0.05) lower in group IV. Although concentrations of serum glucose, Ca, and P and the albumin:globulin (A:G) ratio were similar in the different groups, the total protein, albumin, and serum alkaline phosphatase activity were higher in all of the Zn-supplemented groups on d 70. The serum Zn levels at the end of experimental feeding were significantly higher in groups II and III, whereas serum Mn levels were found to be significantly (p<0.05) higher in groups III and IV. The organ weights (as percentage of body weights) did not show any differences among the treatment groups. Although the Mn concentration was significantly (p<0.05) higher in the pancreas, the Cu concentration was significantly (p<0.05) reduced in the spleen in all of the Zn-supplemented groups. The humoral immune response (antibody titer values) on d 14 of vaccination was significantly (p<0.05) higher in all of the Zn-supplemented groups. It was concluded that the 20-ppm level of Zn in the diet might be adequate for growth and nutrient utilization in guinea pigs, but supplementation of 20-ppm zinc significantly improved the immune response and impact was more prominent with the ZAAC (organic source) compared to ZnSO₄ (inorganic source).     

Carrier-mediated delivery of peptidic drugs for cancer therapy

Protein and peptide drugs are used for treatment of a variety of ailments. However, their wider use has been hindered by issues such as poor bioavailability in vivo and the cost involved in producing these drugs. This review discusses the various carrier-mediated methods used for delivery of peptide and protein drugs, with emphasis on liposomal and microspherical drug delivery systems. A brief look at the types of peptidic drugs currently in use clinically, and a brief discourse on several novel ideas for better protein delivery systems for cancer therapy is included.