Fetal tissue engineering: in vitro analysis of muscle constructs

Background/purpose: This study was aimed at examining the impact of different tissue engineering techniques on fetal muscle construct architecture.Methods: Myoblasts from ovine specimens of fetal skeletal muscle were expanded in culture and their growth rates determined. Cells were seeded at different densities onto 3 scaffold types, namely polyglycolic acid (PGA) treated with poly-l-lactic acid (PLLA), a composite of PGA with poly-4-hydroxybutyrate (P4HB), and a collagen hydrogel. Constructs were maintained in a bioreactor and submitted to histologic, scanning electron microscopy, and DNA analyses at different time-points. Statistical analysis was by the likelihood ratio and paired Student’s t tests (P < .05).Results: Fetal myoblasts proliferated at faster rates than expected from neonatal cells. Cell attachment was enhanced in the PGA/PLLA matrix and collagen hydrogel when compared with the PGA/P4HB composite. Necrosis was observed at the center of all constructs, directly proportional to cell seeding density and time in the bioreactor.Conclusions: Fetal myoblasts can be expanded rapidly in culture and attach well to PGA/PLLA, as well as collagen hydrogel but less optimally to PGA/P4HB. Excessive cell seeding density and bioreactor time may worsen final construct architecture. These findings should be considered during in vivo trials of muscle replacement by engineered fetal constructs.     

Immunogenicity of a new Salmonella Typhi Vi polysaccharide vaccine--vax-TyVi--in Cuban school children and teenagers

A randomized, controlled, double blind study was carried out in Cuban children and teenagers aged 9-13 years to evaluate the immunogenicity of vax-TyVi-Salmonella Typhi Vi polysaccharide vaccine-with respect control vaccines. Serum samples were taken before and 21 days after the immunization, and ELISA was used for the determination of antibodies to Vi polysaccharide. Subjects who received vax-TyVi and TYPHIM Vi (Pasteur-Mérieux) showed seroconversion rates of 85.61 and 78.36%, respectively. The geometric mean titer (GMT) values for Vi antibodies induced after vaccination were 6.27 microg/ml (5.40-7.38 microg/ml) and 5.97 microg/ml (5.01-7.10 microg/ml), respectively. In contrast, subjects receiving the tetanus toxoid vaccine showed 0% seroconversion.     

Prevalence of near vision deficiency and related factors: a population-based study

The objective of this article was to estimate the prevalence of presbyopia in adults > or = 30 years and explore associated characteristics such as demographic, socioeconomic, and individual variables. A cross-sectional, population-based study was performed with 3,007 adults > or = 30 years in Pelotas, Rio Grande do Sul, Brazil. Near vision acuity was evaluated using the Jaeger table, and other variables were investigated using standardized, pre-coded questionnaires. Prevalence of presbyopia was 54.7%. When visual acuity was measured using visual corrective means, prevalence was 29.34%. Age and female gender were associated with the outcome variable after controlling for confounding. Some 42.4% of the sample reported not requiring near vision for routine daily tasks. The conclusion was that presbyopia displays a high prevalence in the adult population and is directly related to increasing age, especially 45 years of age and appearing earlier in women. In some 30% of individuals who already use visual corrective means, the latter are ineffective for near vision.     

Urinary bladder lesions induced by persistent chronic low-dose ionizing radiation

The incidence of urinary bladder cancer in the Ukraine increased from 26.2 to 43.3 per 100 000 population between 1986 and 2001 after the Chernobyl accident. The present study was conducted to evaluate the development of radiation-dependent lesions in the urinary bladders of people living in cesium 137 (¹³⁷Cs) radio-contaminated areas of the Ukraine. Bladder urothelial biopsies from 159 male and 5 female patients were subjected to histological examination and immunohistochemical study of p38 mitogen-acti-vated protein kinase (MAPK), as well as the p50 and p65 subunits of nuclear factor kappa B (NF- k B). A pattern of chronic proliferative atypical cystitis accompanied with large areas of sclerosis of connective tissue in the lamina propria was commonly observed in all cases. Interestingly, these lesions were associated with a dramatic increase in the incidences of dysplasia/carcinoma in situ , and, moreover, small urothelial carcinomas were incidentally detected. We defined the overall condition as "Chernobyl cystitis.'Greatly elevated levels of p38, p65 and p50 expression in the urothelium were evident and the patients showed increased ¹³⁷Cs in urine. The data support conclusions from our previous studies of a critical role for increased oxidative stress in generation of urinary bladder urothelial lesions in individuals chronically exposed to low-dose ¹³⁷Cs radiation. Alterations in the p38 MARK cascade and accumulation of NF- k B subunits could be crucial early molecular events in the pathogenesis of Chernobyl cystitis. (Cancer Sci 2003; 94: 328–333)     

Olfactory dysfunction in hereditary ataxia and basal ganglia disorders

In the present study the olfactory system of hereditary ataxia patients was tested using the smell identification test. Two previous findings suggested a possible olfactory impairment in these patients. First, an olfactory dysfunction has been found in different neurodegenerative diseases, and second, human functional imaging has shown cerebellar activation during olfaction. As an initial approach to determine if cerebellar ataxia impairs the olfactory process, cerebellar ataxia patients, along with basal ganglia patients, were tested. The results show an olfactory deficit in both basal ganglia and hereditary ataxia patients. Further exploration of the olfactory capacities in hereditary ataxia is necessary to elucidate the specific nature of the deficits.