Chitosan isolation from the chitosan-glucan complex of fungal cell wall using amylolytic enzymes

The chitosan/glucan complex isolated from the mycelia of the fungus, Gongronella butleri USDB 0201 can be cleaved with a heat-stable -amylase at 65 °C for 3 h. This results in the removal of the glucan side chain and gives a chitosan solution with 100 times lower turbidity. It is proposed that chitosan and glucan chains are bound by an (1 to 4) glucosidic bond. Both fungal chitosan and fungal glucan have been purified separately.     

Sulfated chitin and chitosan as novel biomaterials

Chitin and chitosan are known to be natural polymers and they are non-toxic, biodegradable and biocompatible. Chemical modification of chitin and chitosan with sulfate to generate new bifunctional materials is of interest because the modification would not change the fundamental skeleton of chitin and chitosan, would keep the original physicochemical and biochemical properties and finally would bring new or improved properties. The sulfated chitin and chitosan have a variety of applications, such as, adsorbing metal ions, drug delivery systems, blood compatibility, and antibacterial field. The purpose of this review is to take a closer look about the different synthetic methods and potential applications of sulfated chitin and chitosan. Based on current research and existing products, some new and futuristic approaches in this context area are discussed in detail. From the studies reviewed, we concluded that sulfated chitin and chitosan are promising materials for biomedical applications.     

Chitosan as a growth stimulator in orchid tissue culture

The effect of shrimp and fungal chitosan on the growth and development of orchid plant meristemic tissue in culture was investigated in liquid and on solid medium. The growth of meristem explants into protocorm-like bodies in liquid medium was accelerated up to 15 times in the presence of chitosan oligomer, the optimal concentration being 15 ppm. The 1 kDa shrimp oligomer was slightly more effective compared to 10 kDa shrimp chitosan and four times more active compared to high molecular weight 100 kDa shrimp chitosan. The 10 kDa fungal chitosan was more effective compared with 1 kDa oligomer. The development of orchid protocorm into differentiated orchid tissue with primary shoots and roots was studied on solid agar medium. The optimal effect, the generation of 5–7 plantlets in 12 weeks was observed in the presence of 20 ppm using either 10 kDa fungal or 1 kDa oligomer shrimp chitosan. The data are consistent with preliminary results from field experiments and confirm unequivocally that a minor amount of chitosan has a profound effect on the growth and development of orchid plant tissue.     

Variables associated with corneal confocal microscopy parameters in healthy volunteers: implications for diabetic neuropathy screening

Diabet. Med. 29, e297-e303 (2012) ABSTRACT: Aim Corneal confocal microscopy is a promising screening method for diabetic neuropathy. Although much research in this field has been accomplished, we aimed to determine and confirm the known clinical and eyewear variables associated with the parameters of corneal confocal microscopy specifically in healthy volunteers, in particular associations with corneal nerve fibre length. Methods Clinical characteristics, electrophysiological examination and a general clinical eye history were collected from 64 healthy volunteers. Corneal confocal microscopy was performed to determine corneal nerve fibre length, corneal nerve branch density, corneal nerve fibre density and tortuosity coefficient. Univariate and multivariate linear regression analysis was used to determine clinical variables associated with corneal nerve fibre length parameters. Results We observed that corneal nerve fibre length has a broad distribution in healthy volunteers (18?±?4?mm/mm(2) , 95% confidence interval, 12.3-25.7?mm/mm(2) ). Multivariate regression analysis demonstrated that HbA(1c) was the only independent clinical factor to account for variations in corneal nerve fibre length, independent of age and status of contact lens wear. Conclusions This study does not provide convincing evidence that corneal nerve fibre length is independently associated with age or the wearing of contact lenses, and that these factors are therefore unlikely to hinder valid screening for polyneuropathies such as diabetic neuropathy. Furthermore, the strong inverse association of corneal nerve fibre length with glycaemic exposure may support the use of this parameter to detect subclinical pre-diabetic nerve injury.     

Synthesis and characterization of α(v)β(3)-targeting peptidomimetic chelate conjugates for PET and SPECT imaging

There is growing interest in small peptidomimetic α(v)β(3) integrin antagonists that are readily synthesized and characterized and can be easily handled using physiological conditions. Peptidomimetic 4-[2-(3,4,5,6-tetrahydropyrimidine-2-ylamino)ethyloxy]benzoyl-2-[N-(3-amino-neopenta-1-carbamyl)]-aminoethylsulfonyl-amino-β-alanine (IAC) was successfully conjugated to 1-(1-carboxy-3-carbo-t-butoxypropyl)-4,7-(carbo-tert-butoxymethyl)-1,4,7-triazacyclononane (NODA-GA(tBu)(3)) and 1-(1-carboxy-3-carbotertbutoxymethyl)-1,4,7,10-tetraazacyclododecane (DOTA-GA(tBu)(4)) and radiolabeled with (111)In, (67)Ga and (203)Pb. Results of a radioimmunoassay demonstrated binding to purified α(v)β(3) integrin when 1-4equiv of integrin were added to the reaction. Based on this promising result, investigations are moving forward to evaluate the NODA-GA-IAC and DOTA-GA-IAC conjugates for targeting tumor associated angiogenesis and α(v)β(3) integrin positive tumors to define their PET and SPECT imaging qualities as well as their potential for delivery of therapeutic radionuclides.     

3-Amino-2-hydroxyamides and related compounds as inhibitors of methionine aminopeptidase-2

Substituted 3-amino-2-hydroxyamides and related hydroxyamides and acylhydrazines were identified as inhibitors of human methionine aminopeptidase-2 (MetAP2). Examination of substituents through parallel synthesis and iterative structure-based design allowed the identification of potent inhibitors with good selectivity against MetAP1. Diacylhydrazine 3t (A-357300) was identified as an analogue displaying inhibition of methionine processing and cellular proliferation in human microvascular endothelial cells (HMVEC).     

Inhibition of nebulin and connectin (titin) for assembly of actin filaments during myofibrillogenesis

In order to examine the role of cytoskeletal scaffolding proteins, nebulin and connectin (titin), in actin dynamics during myofibrillogenesis, rhodamine (rh)-labeled actin was microinjected into cultured skeletal muscle cells in which the function of these proteins had been inhibited with their respective antibodies. In the nebulin function-inhibited cells, exogenously introduced actin formed irregularly distributed amorphous patches or bright foci inside the cells, but it was not incorporated into myofibrillar structures at any stage. Thus, the blockage of actin binding sites of nebulin seems to inhibit the association of actin monomers to the preexisting nebulin scaffold. In the cells inhibited with anti-connectin antibody, incorporation of rh-actin was similar to that in antibody-uninjected cells. These results support the idea that nebulin is related to the accessibility/exchangeability of actin into nascent myofibrils, but connectin does not have such a role in actin assembly. Since all antibodies recognizing different domains of nebulin filaments blocked actin incorporation along the entire length of actin filaments, inhibition of any domains of nebulin filaments seems to affect actin dynamics.     

A Bayesian phase 2 model based adaptive design to optimise antivenom dosing: Application to a dose-finding trial for a novel Russell’s viper antivenom in Myanmar

For most antivenoms there is little information from clinical studies to infer the relationship between dose and efficacy or dose and toxicity. Antivenom dose-finding studies usually recruit too few patients (e.g. fewer than 20) relative to clinically significant event rates (e.g. 5%). Model based adaptive dose-finding studies make efficient use of accrued patient data by using information across dosing levels, and converge rapidly to the contextually defined ‘optimal dose’. Adequate sample sizes for adaptive dose-finding trials can be determined by simulation. We propose a model based, Bayesian phase 2 type, adaptive clinical trial design for the characterisation of optimal initial antivenom doses in contexts where both efficacy and toxicity are measured as binary endpoints. This design is illustrated in the context of dose-finding for Daboia siamensis (Eastern Russell’s viper) envenoming in Myanmar. The design formalises the optimal initial dose of antivenom as the dose closest to that giving a pre-specified desired efficacy, but resulting in less than a pre-specified maximum toxicity. For Daboia siamensis envenoming, efficacy is defined as the restoration of blood coagulability within six hours, and toxicity is defined as anaphylaxis. Comprehensive simulation studies compared the expected behaviour of the model based design to a simpler rule based design (a modified ‘3+3’ design). The model based design can identify an optimal dose after fewer patients relative to the rule based design. Open source code for the simulations is made available in order to determine adequate sample sizes for future adaptive snakebite trials. Antivenom dose-finding trials would benefit from using standard model based adaptive designs. Dose-finding trials where rare events (e.g. 5% occurrence) are of clinical importance necessitate larger sample sizes than current practice. We will apply the model based design to determine a safe and efficacious dose for a novel lyophilised antivenom to treat Daboia siamensis envenoming in Myanmar.     

Expression of hemagglutinin protein from the avian influenza virus H5N1 in a baculovirus/insect cell system significantly enhanced by suspension culture

Background  

Prevention of a possible avian influenza pandemic necessitates the development of rapid diagnostic tests and the eventual production of a vaccine.     

Are Husbands Involving in Their Spouses’ Utilization of Maternal Care Services?: A Cross-Sectional Study in Yangon,Myanmar

IntroductionHusbands can play a crucial role in pregnancy and childbirth, especially in patriarchal societies of developing countries. In Myanmar, despite the critical influence of husbands on the health of mothers and newborns, their roles in maternal health have not been well explored. Therefore, the aim of this study was to identify the factors associated with husbands’ involvement in maternal health in Myanmar. This study also examined the associations between husbands’ involvement and their spouses’ utilization of maternal care services during antenatal, delivery and postnatal periods.MethodsA community-based, cross sectional study was conducted with 426 husbands in Thingangyun Township, Yangon, Myanmar. Participants were husbands aged 18 years or older who had at least one child within two years at the time of interview. Face to face interviews were conducted using a pretested structured questionnaire. Factors associated with the characteristics of husband’s involvement as well as their spouses’ utilization of maternal care services were analyzed by multivariable logistic regression models.ResultsOf 426 husbands, 64.8% accompanied their spouses for an antenatal visit more than once while 51.6% accompanied them for a postnatal visit. Husbands were major financial supporters for both antenatal (95.8%) and postnatal care (68.5%). Overall, 69.7% were involved in decision making about the place of delivery. Regarding birth preparedness, the majority of husbands prepared for skilled birth attendance (91.1%), delivery place (83.6%), and money saving (81.7%) before their spouses gave birth. In contrast, fewer planned for a potential blood donor (15.5%) and a safe delivery kit (21.1%). In the context of maternal health, predictors of husband’s involvement were parity, educational level, type of marriage, decision making level in family, exposure to maternal health education and perception of risk during pregnancy and childbirth. Increased utilization of maternal health services was found among spouses of husbands who accompanied them to antenatal visits (AOR 5.82, 95% CI, 3.34–10.15) and those who had a well birth plan (AOR 2.42, 95% CI, 1.34–4.39 for antenatal visit and AOR 2.88, 95% CI, 1.52–5.47 for postnatal visit).ConclusionThe majority of husbands supported their spouses’ maternal care services use financially; however, they were less involved in birth preparedness and postnatal care. Exposure to maternal health education and their maternal health knowledge were main predictors of their involvement. Women were more likely to use maternal care services when their husbands company them for ANC visits and had a well-birth plan in advance.