2,080 research outputs found
Crystallization of a nonreplicating rotavirus vaccine candidate.
Nonreplicating rotavirus vaccine (NRRV) candidates are being developed with the aim of serving the needs of developing countries. A significant proportion of the cost of manufacturing such vaccines is the purification in multiple chromatography steps. Crystallization has the potential to reduce purification costs and provide new product storage modality, improved operational flexibility, and reduced facility footprints. This communication describes a systematic approach for the design of the crystallization of an NRRV candidate, VP8 subunit proteins fused to the P2 epitope of tetanus toxin, using first-principles models and preliminary experimental data. The first-principles models are applied to literature data to obtain feasible crystallization conditions and lower bounds for nucleation and growth rates. Crystallization is then performed in a hanging-drop vapor diffusion system, resulting in the nucleation and growth of NRRV crystals. The crystals obtained in a scaled-up evaporative crystallization contain proteins truncated in the P2 region, but have no significant differences with the original samples in terms of antibody binding and overall conformational stability. These results demonstrate the promise of evaporative crystallization of the NRRV
Holistic process development to mitigate proteolysis of a subunit rotavirus vaccine candidate produced in Pichia pastoris by means of an acid pH pulse during fed‐batch fermentation
To meet the challenges of global health, vaccine design and development must be reconsidered to achieve cost of goods as low as 15¢ per dose. A new recombinant protein‐based rotavirus vaccine candidate derived from non‐replicative viral subunits fused to a P2 tetanus toxoid CD4(+) T cell epitope is currently under clinical development. We have sought to simplify the existing manufacturing process to meet these aims. To this end, we have taken a holistic process development approach to reduce process complexity and costs while producing a product with the required characteristics. We have changed expression system from Escherichia coli to Pichia pastoris, to produce a secreted product, thereby reducing the number of purification steps. However, the presence of proteases poses challenges to product quality. To understand the effect of fermentation parameters on product quality small‐scale fermentations were carried out. Media pH and fermentation duration had the greatest impact on the proportion of full‐length product. A novel acidic pH pulse strategy was used to minimize proteolysis, and this combined with an early harvest time significantly increased the proportion of full‐length material (60–75%). An improved downstream process using a combination of CIEX and AIEX to further reduce proteases, resulted in maintaining product quality (95% yield)
Effects of altitude on circadian rhythm of adult locomotor activity in Himalayan strains of Drosophila helvetica
BACKGROUND: We recently reported that the altitude of origin altered the photic and thermal sensitivity of the circadian pacemaker controlling eclosion and oviposition rhythms of high altitude Himalayan strains of Drosophila ananassae. The present study was aimed at investigating the effects of altitude of origin on the pacemaker controlling the adult locomotor activity rhythm of D. helvetica. METHODS: Locomotor activity rhythms of the high altitude Himalayan (haH) strain (Hemkund-Sahib, 4,121 m above sea level) and the low altitude Himalayan (laH) strain (Birahi, 1,132 m a.s.l.) of D. helvetica were assayed by two experiments. The first experiment examined the natural entrainment pattern in light-dark (LD) cycles at the breeding site of each strain. The second experiment examined the entrainment parameters in LD 12:12 cycles and the period of free-running rhythm in constant darkness (DD) under controlled laboratory conditions. RESULTS: When entrained by natural or artificial LD cycles, the haH strain had an unimodal activity pattern with a single peak that commenced in the forenoon and continued till evening, while the laH strain had a bimodal activity pattern in which the morning peak occurred before lights-on and was separated by about 4 h from the evening peak. Unimodality of the haH strain was retained in DD; however, bimodality of the laH strain was abolished in DD since the evening peak disappeared immediately after the trasfer from LD 12:12 to DD. The period of the free-running rhythm of the haH strain was ~26.1 h, whereas that of the laH strain was ~21.7 h. CONCLUSION: Parameters of entrainment and free-running rhythm of the adult locomotor activity of the haH strain of D. helvetica were strikingly different from those of the laH strain and were likely due to ecological adaptations to the prevailing environmental conditions at the altitude where the species evolved
Infant feeding practices of mothers in an urban area in Nepal
Abstract Background: Child health in developing countries including Nepal is a matter of serious concern as the prevalence of malnutrition among children continues to be high with 48.6% of children under five in Nepal being underweight. Since infant feeding practices adopted by mothers play a major role in influencing health of these children, there is a need to study the infant feeding practices prevalent in different areas in order to have pragmatic approaches to solve this problem. Materials and methods: A cross sectional study was conducted among mothers who attended the immunization clinics of 18 wards of Pokhara municipality area. They were interviewed with a semi-structured questionnaire on various aspects of infant feeding. Result: A total of 168 mothers were interviewed and prevalence of breastfeeding was 99.4% (167). Only 43.5% of the mothers initiated breastfeeding within one hour of birth and 60.5% were practicing exclusive breastfeeding at 5 months. Almost 40% of the mothers started complementary feeding before the recommended age of 6 months and 22.5 % delayed introduction of complementary feeding beyond the recommended age. Conclusion: Breast feeding practices adopted by mothers of Pokhara urban area are still lacking in terms of late initiation of and early starting of complementary feeding. There is a need to educate the mothers regarding proper infant feeding practices
Usefulness of hospital emergency department records to explore access to injury care in Nepal
© 2016, Bhatta et al. Background: Injuries are a major public health problem worldwide. Despite increasing morbidity and mortality from injuries in Nepal, it is not recognised in the government’s policy and programmes and few population-based studies have been published. This study describes the usefulness of hospital emergency department records to explore access to injury care in Nepal. Methods: A retrospective ED-based study was conducted at a governmental hospital in Nepal to review the routinely collected data for 1year (1 January 2010 to 31 December 2010). The study was designed to provide cross-sectional data to describe the distribution of injuries by age, gender, ethnic group and injury mechanism. Results: Results showed that twice as many males as females attended the emergency department (14.6 vs. 7.0 per 1000), attendance varied by age with most (39.8%) attendances in young adults of working age and over half of attendances were from just two ethnic groups (Brahmin (26%) and Tamang (25.5%). Road traffic injuries were the most common cause of injury (37.6%). Conclusions: This study therefore showed the feasibility of using routinely collected hospital emergency department data to monitor injury inequalities in Nepal
QTL Mapping of Combining Ability and Heterosis of Agronomic Traits in Rice Backcross Recombinant Inbred Lines and Hybrid Crosses
BACKGROUND: Combining ability effects are very effective genetic parameters in deciding the next phase of breeding programs. Although some breeding strategies on the basis of evaluating combining ability have been utilized extensively in hybrid breeding, little is known about the genetic basis of combining ability. Combining ability is a complex trait that is controlled by polygenes. With the advent and development of molecular markers, it is feasible to evaluate the genetic bases of combining ability and heterosis of elite rice hybrids through QTL analysis. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we first developed a QTL-mapping method for dissecting combining ability and heterosis of agronomic traits. With three testcross populations and a BCRIL population in rice, biometric and QTL analyses were conducted for ten agronomic traits. The significance of general combining ability and special combining ability for most of the traits indicated the importance of both additive and non-additive effects on expression levels. A large number of additive effect QTLs associated with performance per se of BCRIL and general combining ability, and dominant effect QTLs associated with special combining ability and heterosis were identified for the ten traits. CONCLUSIONS/SIGNIFICANCE: The combining ability of agronomic traits could be analyzed by the QTL mapping method. The characteristics revealed by the QTLs for combining ability of agronomic traits were similar with those by multitudinous QTLs for agronomic traits with performance per se of BCRIL. Several QTLs (1-6 in this study) were identified for each trait for combining ability. It demonstrated that some of the QTLs were pleiotropic or linked tightly with each other. The identification of QTLs responsible for combining ability and heterosis in the present study provides valuable information for dissecting genetic basis of combining ability
Magnetic resonance imaging of abnormal ventricular septal motion in heart diseases: a pictorial review
The purpose of this article is to illustrate the usefulness of MR imaging in the clinical evaluation of congenital and acquired cardiac diseases characterised by ventricular septal wall motion abnormality. Recognition of the features of abnormal ventricular septal motion in MR images is important to evaluate the haemodynamic status in patients with congenital and acquired heart diseases in routine clinical practice
Emergence and maintenance of actionable genetic drivers at medulloblastoma relapse
BACKGROUND: 90% of tumors) and established genetic drivers (e.g. SHH/WNT/P53 mutations; 60% of rMB events) were maintained from diagnosis. Critically, acquired and maintained rMB events converged on targetable pathways which were significantly enriched at relapse (e.g. DNA damage-signaling) and specific events (e.g. 3p loss) predicted survival post-relapse. CONCLUSIONS: rMB is defined by the emergence of novel events and pathways, in concert with selective maintenance of established genetic drivers. Together, these define the actionable genetic landscape of rMB and provide a basis for improved clinical management and development of stratified therapeutics, across disease-course
Invasive carcinomas of the male breast: a morphologic study of the distribution of histologic subtypes and metastatic patterns in 778 cases
The current investigation was conducted to evaluate the proportional distribution of the various histologic subtypes (including newly recognized variants) of male breast carcinomas, to determine whether any histologic subtypes occur with a frequency that is markedly discordant with the expected frequencies from published data on parallel female breast tumors. We also aimed to document the distribution of malignancies metastatic to the breast. Seven hundred fifty-nine archived cases of primary invasive carcinoma involving the male breast were retrieved and subcategorized into histologic subtypes according to contemporary criteria. Six hundred forty-three (84.7%) tumors were pure infiltrating ductal carcinoma (IDC) not otherwise specified. The most common of the remainder included papillary carcinoma with invasion in the form of IDC (n = 34), mixed IDC and mucinous carcinoma (n = 26), and pure mucinous carcinoma (n = 21). In 19 cases, metastases from other sites involved the breast, most commonly (58%) cutaneous melanoma. Invasive carcinoma of the male breast appears to display a morphologic spectrum and distribution of histologic subtypes that is comparable to those of the female breast, with some expected variation. Compared with published experience on their female counterparts, there is a two-fold increase in the frequency of invasive papillary carcinoma in the male breast. Finally, the most common tumor metastatic to the male breast in this series was cutaneous melanoma
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