Limited capacity of human adult islets expanded in vitro to redifferentiate into insulin-producing beta-cells

Limited organ availability is an obstacle to the widespread use of islet transplantation in type 1 diabetic patients. To address this problem, many studies have explored methods for expanding functional human islets in vitro for diabetes cell therapy. We previously showed that islet cells replicate after monolayer formation under the influence of hepatocyte growth factor and selected extracellular matrices. However, under these conditions, senescence and loss of insulin expression occur after >15 doublings. In contrast, other groups have reported that islet cells expanded in monolayers for months progressed through a reversible epithelial-to-mesenchymal transition, and that on removal of serum from the cultures, islet-like structures producing insulin were formed (1). The aim of the current study was to compare the two methods for islet expansion using immunostaining, real-time quantitative PCR, and microarrays at the following time points: on arrival, after monolayer expansion, and after 1 week in serum-free media. At this time, cell aliquots were grafted into nude mice to study in vivo function. The two methods showed similar results in islet cell expansion. Attempts at cell differentiation after expansion by both methods failed to consistently recover a beta-cell phenotype. Redifferentiation of beta-cells after expansion is still a challenge in need of a solution.     

Gender difference as regards myocardial protein oxidation in aged rats: male rats have increased oxidative protein damage

Objective The reasons for the difference in life expectancy between males and females are still unknown. Previous studies have provided compelling evidence for the presence of oxidized proteins, and lipids in advanced human atherosclerotic lesions. The gender factor responsible for such protein oxidation is unknown and controversial. Our aim was to reveal the difference between myocardial protein and lipid oxidation parameters of male and female aged rats. Methods We investigated the relation between myocardial protein carbonyl (PCO) and other protein oxidation parameters such as advanced oxidation protein products (AOPP), nitrotyrosine (NT), protein hydroperoxide (P-OOH), and protein thiol (P-SH). Our study also covered other oxidative stress parameters, such as total thiol (T-SH), non-protein thiol (Np-SH), 4-hydroxyalkenal (4-HAE), malondialdehyde (MDA), reduced glutathione (GSH), and the glutathione disulfide (GSSG). Results Among the studied parameters, myocardial PCO, AOPP, NT, Np-SH, GSH, Fe²⁺ levels and the redox index (RI) of male rats were significantly higher than in the female group. On the other hand, P-OOH, P-SH, T-SH, 4-HAE, and MDA levels were all found to be not different. Conclusions These data support the hypothesis that elevated levels of PCO, AOPP, and NT contribute to the extent of protein, but not lipid, oxidation in aged male rats. We are of the conviction that the increased myocardial Np-SH, GSH and RI levels that we have determined in aged male rats may be a protective factor in propagation of protein oxidation. Our findings support our conviction that protein and lipid oxidation, in the myocardial tissue of aged rats, have a controlling role in differing regulating mechanisms through gender differences.     

Contemporary seasonal influenza A (H1N1) virus infection primes for a more robust response to split inactivated pandemic influenza A (H1N1) Virus vaccination in ferrets

Human influenza pandemics occur when influenza viruses to which the population has little or no immunity emerge and acquire the ability to achieve human-to-human transmission. In April 2009, cases of a novel H1N1 influenza virus in children in the southwestern United States were reported. It was retrospectively shown that these cases represented the spread of this virus from an ongoing outbreak in Mexico. The emergence of the pandemic led to a number of national vaccination programs. Surprisingly, early human clinical trial data have shown that a single dose of nonadjuvanted pandemic influenza A (H1N1) 2009 monovalent inactivated vaccine (pMIV) has led to a seroprotective response in a majority of individuals, despite earlier studies showing a lack of cross-reactivity between seasonal and pandemic H1N1 viruses. Here we show that previous exposure to a contemporary seasonal H1N1 influenza virus and to a lesser degree a seasonal influenza virus trivalent inactivated vaccine is able to prime for a higher antibody response after a subsequent dose of pMIV in ferrets. The more protective response was partially dependent on the presence of CD8(+) cells. Two doses of pMIV were also able to induce a detectable antibody response that provided protection from subsequent challenge. These data show that previous infection with seasonal H1N1 influenza viruses likely explains the requirement for only a single dose of pMIV in adults and that vaccination campaigns with the current pandemic influenza vaccines should reduce viral burden and disease severity in humans.     

Blood mercury levels of dental students and dentists at a dental school.

OBJECTIVE: To determine the blood mercury levels in dental students and clinical teaching staff in a dental school using amalgam as a restorative material. SETTING: A dental school in Ege University, Turkey surveyed during one academic year. SUBJECTS AND METHODS: Cross-sectional study of groups of dental students (n=92) in years I to V, clinical teachers in restorative dentistry (n=16) and controls (n=14). Mercury concentration was estimated in venous blood samples using a cold vapour atomic absorption method at the commencement and end of the academic year. Daily air mercury levels were determined in clinical and teaching areas by measuring the darkening of palladium chloride discs using spectrophotometry. RESULTS: There were statistically significant increases (p<0.001) in plasma mercury concentration between measurements in all groups at the end of the academic year. Red cell mercury levels were also consistently elevated. Although the highest levels of mercury were recorded in persons working with amalgam, increased levels were also found in subjects working in the teaching classrooms but not with amalgam (controls and first year students). CONCLUSION: Increased mercury levels appeared to be due to background exposure from spillage of mercury and amalgam residues on floors. Increased mercury hygiene and regular control of working atmosphere should be implemented to prevent mercury exposure in the dental pre-clinical laboratory.     

Skeletal traction and delayed percutaneous fixation of complicated supracondylar humerus fractures due to delayed or unsuccessful reductions and extensive swelling in children

The functional and radiological results of 13 supracondylar humerus fractures of 13 children were evaluated to determine the efficiency of delayed percutaneous fixation of the fractures after a period of skeletal overhead traction. All the fractures were complicated by delayed reduction, extensive swelling or unsuccessful reduction manipulations. As the unfavourable preexisting factors subsided under skeletal traction, anatomical reduction and fixation of fractures by percutaneous pinning were performed under general anesthesia. The average follow-up period was 21 months. Bauman and lateral capitellohumeral angles were measured and statistically analyzed. Functional and cosmetic results were evaluated by physical examination of the elbows. There were 11 excellent and two fair functional results while all cosmetic results were excellent or good. As a result, skeletal traction and delayed percutaneous pinning is accepted as an alternative method of treatment for complicated supracondylar humerus fractures in children.     

PLC-gamma1 enzyme activity is required for insulin-induced DNA synthesis.

Previously, we had shown that inhibition of PLC activity impaired the ability of insulin to activate ERK in 3T3-L1 adipocytes. In this study, we confirmed that the insulin receptor and PLC-gamma1 are physically associated in hIRcB fibroblasts, insulin stimulates PLC-gamma1 enzyme activity, and inhibition of PLC activity impairs activation of ERK. We subsequently investigated whether PLC-gamma1 is required for insulin-stimulated mitogenesis. First, inhibition of PLC activity using U73122 impairs the ability of insulin to stimulate DNA synthesis. Second, disruption of the interaction of the insulin receptor with PLC-gamma1 by microinjection of SH2 domains derived from PLC-gamma1 or Grb2 but not Shc similarly blocks insulin-induced DNA synthesis. Third, microinjection of neutralizing antibodies to PLC-gamma1 blocks DNA synthesis, but nonneutralizing antibodies do not. The blockade in all three cases is rescued by synthetic diacylglycerols but not by inositol-1,4,5-trisphosphate, indicating a requirement for PLC enzyme activity. These experimental data point to a requirement for PLC-gamma1 in insulin-stimulated mitogenesis in hIRcB cells.     

Studying in vitro release of dexchlorpheniramine maleate from aqueous phases and water/oil emulsions (creams) with various penetration enhancers

The effect of various penetration enhancers on the permeation of dexchlorpheniramine maleate from a 2 wt% aqueous phase and from water-oil emulsions (creams) was studied using a modified Franz diffusion cell. A polyamide membrane filter (modeling a biomembrane) was impregnated with n-octanol, sandwiched between two dialysis membranes, and placed between the source and receiver compartments. The permeation coefficient in the aqueous phase was 270 times greater than that in the cream, while the lag time was 3.5 times longer in the cream. A mixture of isopropyl myristate and ethanol (8: 2) gave the highest enhancement ratio, while oleic acid acted as a penetration retardant in the cream formulation. Published in Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 6, pp. 39–43, June, 2007.     

Surgical outcomes of ulnar nerve lesions in children. A retrospective clinical study

The ulnar nerve provides the major motor innervation of the interosseous muscles of the hand and the flexor muscles of the wrist and the fourth and fifth digits. Injury is most common at the wrist, forearm or elbow, secondary to trauma or entrapment. Pediatric ulnar nerve lesions differ from adult lesions by their quicker axonal regeneration. Neural plasticity is also greater in children. We analyzed 21 pediatric patients with ulnar nerve lesion who underwent surgical treatment between 1995 and 2002 to determine if there were differences in the neurological outcome in terms of the type of lesion and surgery. Data showed that excellent results were found in 100% of the lesions treated by simple decompression and nearly 58% of the lesions treated by neurolysis. Good results were obtained in 33% of lesions treated by neurolysis. There were fair results for surgery performed in discontinuous lesions.