Immunologic Hyporesponsiveness to Serogroup C but Not Serogroup A following Repeated Meningococcal A/C Polysaccharide Vaccination in Saudi Arabia

In Saudi Arabia, vaccination with the meningococcal A/C polysaccharide (MACP) vaccine is advised every 3 years. A clinical outcome study was performed to test the effect of repeat vaccination with the MACP vaccine on the immune responses among Saudi nationals who live in the Makkah and Jeddah areas. Subjects (n = 230) aged 10 to 29 years were selected: 113 subjects with two or more prior vaccinations with the MACP vaccine, 79 subjects with one prior vaccination with the MACP vaccine, and 38 subjects naïve to vaccination with the MACP vaccine. All subjects received the MACP vaccine in 2002, and serum bactericidal antibody (SBA) titers were measured before and 1 month after vaccination with the MACP vaccine. For serogroup C, geometric mean SBA titers 1 month following vaccination with the MACP vaccine were 708.6 (95% confidence interval [CI], 217.5 to 2,308.9) for those naïve to prior vaccination with the MACP vaccine, and they were significantly higher (P < 0.0001) than 25.0 (95% CI, 12.4 to 50.2) for those who had received one prior vaccination with the MACP vaccine and 32.4 (95% CI, 18.7 to 56.4) for those who had received two or more doses of the MACP vaccine. For serogroup A, the geometric mean SBA titer 1 month after receipt of the MACP vaccine was 1,649.3 (95% CI, 835.2 to 3,256.9) for those naïve to prior vaccination, and the titers were lower (P = 0.67) than 2,185.7 (95% CI, 1,489.4 to 3,207.7) for those who had received one prior dose of the MACP vaccine and significantly lower (P = 0.042) than 3,540.8 (95% CI, 2,705.2 to 4,634.5) for those who had received two or more doses of the MACP vaccine. For serogroup C, the proportions of nonresponders (SBA titers, <8) were 19% for the naïve cohort, 52% for the cohort with one prior vaccination, and 49% for the cohort with two or more prior vaccinations. Following repeated doses of the MACP vaccine, hyporesponsiveness to serogroup C is evident, with high percentages of MACP vaccinees having SBA titers below the putative protective SBA titer. Serogroup A responses following vaccination with the MACP vaccine were boosted. Introduction of the serogroup C conjugate vaccine would provide long-term protection against serogroup C disease; however, quadrivalent conjugate vaccines are required to provide long-time protection against disease caused by serogroups A, W135, and Y.     

Carrageenan-Induced Suppression of T-Lymphocyte Proliferation in the Rat: Abrogation of Suppressor Factor Production by the Prostaglandin Synthesis Inhibitors,Indomethacin and ETYA

Carrageenan, an algal polygalactan reputed to be selectively toxic for macrophages, is widely employed as a tool to dissect pathways of cell-mediated immunity. In the present study, corn oil-elicited rat peritoneal macrophages after 72 h culture with 10 μg/ml Seakem® 9 Carrageenan secreted a soluble suppressor factor capable of abrogating T-cell activation by phytohemagglutinin-P (PHA). Addition of the prostaglandin synthesis inhibitors Indometha-cin or 5,8,11,14-eicosatetraynoic acid (ETYA) prevented inhibitor synthesis by Carrageenan-conditioned macrophages. Seakem ® 9 and lambda Carrageenans added directly into spleen cell cultures failed to diminish lymphocyte proliferation, but rather stimulated spleen cell division. Macrophages cultured with low concentrations of Carrageenan appeared to be activated on the basis of enhanced tumoristatic capacity against Schmidt-Ruppin sarcoma cells. Thus, macrophages activated by low concentrations of Carrageenan in vitro appear to secrete a product of arachidonic acid metabolism which is a potent inhibitor of PHA-induced spleen cell mitogenesis.     

Optimizing the HIV/AIDS informed consent process in India

Background

While the basic ethical issues regarding consent may be universal to all countries, the consent procedures required by international review boards which include detailed scientific and legal information, may not be optimal when administered within certain populations. The time and the technicalities of the process itself intimidate individuals in societies where literacy and awareness about medical and legal rights is low.

Methods

In this study, we examined pregnant women's understanding of group education and counseling (GEC) about HIV/AIDS provided within an antenatal clinic in Maharashtra, India. We then enhanced the GEC process with the use of culturally appropriate visual aids and assessed the subsequent changes in women's understanding of informed consent issues.

Results

We found the use of visual aids during group counseling sessions increased women's overall understanding of key issues regarding informed consent from 38% to 72%. Moreover, if these same visuals were reinforced during individual counseling, improvements in women's overall comprehension rose to 96%.

Conclusions

This study demonstrates that complex constructs such as informed consent can be conveyed in populations with little education and within busy government hospital settings, and that the standard model may not be sufficient to ensure true informed consent.     

Genomic screening for beta-sarcoglycan gene mutations: missense mutations may cause severe limb-girdle muscular dystrophy type 2E (LGMD 2E)

Autosomal recessive limb-girdle muscular dystrophies (LGMDs) are genetically heterogeneous. A subgroup of these disorders is caused by mutations in the dystrophin-associated sarcoglycan complex. Truncating mutations in the 43 kDa beta-sarcoglycan gene (LGMD 2E) were originally identified in a sporadic case of Duchenne-like muscular dystrophy, and a common missense mutation (T151R) was identified independently in Indiana Amish pedigrees with a milder form of LGMD. To facilitate mutational analysis of larger numbers of patients directly from genomic DNA, as opposed to reverse transcribed RNA from muscle biopsies, we have determined the genomic structure of the beta-sarcoglycan gene. The open reading frame of the beta-sarcoglycan coding region extends over six exons. Primers were designed for PCR amplification of single exons from genomic DNA and subsequent single strand conformation polymorphism (SSCP) analysis. We screened 15 patients from the Brazilian LGMD patient population, 13 of whom followed a severe course. Most of the patients had been assessed previously for deficiency of alpha- sarcoglycan immunofluorescence on muscle biopsy sections as a marker for disease of the sarcoglycan complex. Novel mutations in two familial and two sporadic cases of severe childhood-onset LGMD were identified. Only one of these patients carried a truncating mutation (homozygous 2 bp deletion, FS164TER), while the other three carried missense mutations (homozygous R91P, homozygous M100K, heterozygous recessive L108R; only one allele could be identified in this family). All three missense mutations occurred in exon 3, coding for the immediate extracellular domain. Complete absence for all three of the known sarcoglycans was noted by immunohistochemistry on muscle biopsy sections of the patients.      

Detection of damage to the mitochondrial genome in the oncocytic cells of Warthin's tumour

Warthin's tumour of the salivary glands is composed of oncocytic cells containing excessive numbers of mitochondria which show frequent structural abnormalities and reduced metabolic function. Recent evidence of a strong association between cigarette smoking and the occurrence of Warthin's tumour prompted this study, to look for evidence of damage to mitochondrial DNA (mtDNA) that could be the result of an increase in oxidative stress; two-colour fluorescence in situ hybridization (FISH) was developed to show the distribution of mitochondria with deleted mtDNA in paraffin wax-embedded material. Approximately 10% of mtDNA bears the 'common' 4977 bp deletion. Using the polymerase chain reaction (PCR), the 4977 bp deletion was further quantified, in Warthin's tumour and age-matched normal parotid control tissue. Whilst the deletion was present in all parotid tissue, its presence was significantly higher in oncocytic tumour cells. In a small number of controls, there was a trend towards higher concentrations of the deletion in smokers.     

Three Dact gene family members are expressed during embryonic development and in the adult brains of mice.

Members of the Dact protein family initially were identified through binding to Dishevelled (Dvl), a cytoplasmic protein central to Wnt signaling. During mouse development, Dact1 is detected in the presomitic mesoderm and somites during segmentation, in the limb bud mesenchyme and other mesoderm-derived tissues, and in the central nervous system (CNS). Dact2 expression is most prominent during organogenesis of the thymus, kidneys, and salivary glands, with much lower levels in the somites and in the developing CNS. Dact3, not previously described in any organism, is expressed in the ventral region of maturing somites, limb bud and branchial arch mesenchyme, and in the embryonic CNS; of the three paralogs, it is the most highly expressed in the adult cerebral cortex. These data are consistent with studies in other vertebrates showing that Dact paralogs have distinct signaling and developmental roles and suggest they may differentially contribute to postnatal brain physiology.     

Differential effects of cAMP and serotonin on membrane current, action-potential duration, and excitability in somata of pleural sensory neurons of Aplysia

1. In somata of sensory neurons in the pleural ganglia of Aplysia californica, serotonin (5-HT) modulates at least three K+ currents: the S K+ current (IK,S), a slow component of the Ca2(+)-activated K+ current (IK,Ca), and the delayed or voltage-dependent K+ current (IK,V). The modulation of IK,S and the slow component of IK,Ca by 5-HT has been shown previously to be mediated via adenosine 3',5'-cyclic monophosphate (cAMP). To determine whether the modulation of IK,V by 5-HT also is mediated via cAMP, we used two-electrode voltage-clamp techniques to compare the modulation of membrane current by cAMP and 5-HT. 2. Current responses were elicited by brief (200 ms) voltage-clamp pulses before and after the bath application of analogues of cAMP. At all voltage-clamp potentials examined (-40-30 mV), analogues of cAMP reduced the amplitude of the current response. The properties of the cAMP-sensitive component of membrane current were revealed by computer subtraction of current responses elicited in the presence of the analogue of cAMP from current responses elicited before application of the analogue. The characteristics of the resulting cAMP difference current (IcAMP) suggested that cAMP modulated a component of membrane current that was relatively voltage independent, did not inactivate, and was active over a wide range of membrane potentials. In addition, the current-voltage (I-V) relationship of the cAMP difference current had a positive slope. These properties of the cAMP difference current were consistent with those of IK,S but did not indicate that IK,V was modulated by cAMP. 3. The cAMP-independent modulation of membrane current by 5-HT was examined by eliciting current responses first in the presence of an analogue of cAMP and again after the addition of 5-HT to the bath, which still contained the analogue. The presence of the analogue of cAMP occluded further modulation of IK,S by 5-HT. However, the analogue of cAMP did not occlude the modulation of IK,V by 5-HT. This cAMP-independent effect of 5-HT on membrane current was revealed by computer subtraction of current responses elicited in the presence of 5-HT from current responses elicited before the application of 5-HT (the analogue of cAMP was present throughout). The resulting cAMP-independent 5-HT difference current (I5-HT) was highly voltage dependent, had complex kinetics, and its I-V relationship had a negative slope at membrane potentials above 0 mV.(ABSTRACT TRUNCATED AT 400 WORDS)     

Radioimmunoassay for insulin-like growth factor (IGF) II: interference by pure IGF-binding proteins.

A new radioimmunoassay for insulin-like growth factor-II (IGF-II) is described. Compared to recombinant DNA-derived IGF-II standard, the cross-reactivity of natural or recombinant IGF-I was less than 1%. The ED50 for IGF-II standard was 1.0 ng/ml, and the mean IGF-II level in acid-ethanol-extracted serum from healthy adults was 525 +/- 87 ng/ml (SD, n = 30). Addition of the IGF binding protein IGFBP-1 (BP-28, PP12) caused dose-dependent inhibition of IGF-II tracer binding to antiserum, increasing to greater than 90% inhibition at 400 ng/ml IGFBP-1. In contrast, the IGF binding protein IGFBP-3 (BP-53) caused approximately 30% inhibition of tracer binding at 20 ng/ml IGFBP-3, with no further inhibition up to 400 ng/ml IGFBP-3. The influence of added IGF binding proteins on IGF-II displacement curves varied depending on both the type and concentration of binding protein added. It is concluded that interference in IGF radioimmunoassays by IGF binding proteins depends both on the types of binding proteins present, and on the IGF concentration, in the test samples.