Neural tissue engineering: Adrenal chromaffin cell attachment and viability on chitosan scaffolds

Abstract

This study introduces chitosan-based matrices as cell substrates for bovine chromaffin cell attachment in transplantation procedures. Chitosan ([1 → ] linked 2-amino-2-deoxy-β-O-glucopyranose), having structural similarity to glycosaminoglycans, was modified using several proteins (collagen, albumin and gelatin) to increase surface area and improve biocompatibility. In vitro, collagen-blended chitosan (CC) matrices were found to attach more readily to chromaffin cells than to gelatin- or albumin-blended matrices. Morphological evidence showed that the chromaffin cells attached to CC substrates integrated well with the hydrogel matrix and survived for at least two weeks, under in vivo culture conditions. The chromaffin cells within chitosan scaffolds also survived for at least two weeks in vitro and after subarachnoid grafting to rats. [Neural Res 1998; 20: 648–654]     

Dust Mite Species and Allergen Concentrations in Beds of Individuals Belonging to Different Urban Socioeconomic Groups in Brazil

Background. Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis dust mites are among the most important agents of hypersensitivity reactions in human beings. However, a role of other mites in the etiology of these reactions has not yet been excluded.

Objectives. To investigate the nature of the dust mite fauna and the presence of Der p 1 (allergen 1 of Dermatophagoides pteronyssinus) and Blo t 5 (allergen 5 of Blomia tropicalis) on beds used by individuals with different socioeconomic backgrounds in Salvador, a major Brazilian city and to investigate possible associations of mite frequencies and allergen levels with (a) season of the year, (b) housing characteristics, (c) bed cleaning behaviors that could affect mite densities, and (d) allergy history.

Methods. Dust samples were collected from 459 beds of 101 residences from two groups with different socioeconomic levels (hereafter called wealthy and poor groups) in the city of Salvador, Brazil, for the identification of mite species and determination of Der p 1 and Blo t 5 levels. History of allergy was collected using the ISAAC phase I questionnaire.

Results. Eighty nine percent of the beds analyzed harbored at least one mite species. B. tropicalis was found in 71.8%, D. pteronyssinus in 39.9%, Cheyletus sp. in 33.9%, and Gohieria fusca in 21.1% of the beds. B. tropicalis was found with a similar frequency in beds of the two socioeconomic groups; D. pteronyssinus was found more frequently in the beds of the wealthy than of the poor group, whereas the reverse was observed with G. fusca. The concentrations of Der p 1 and Blo t 5 allergens exceeded the cut-off for sensitization of 2 μg/g of dust in 94.0% and 69.3% of the wealthy and poor group beds, respectively. No associations were found between history of allergy and mite species or between history of allergy and the concentrations of mite allergens.

Conclusions. The observation of B. tropicalis and D. pteronyssinus as the most frequently found mites is consistent with previous reports from tropical regions. The higher frequency of G. fusca in beds of individuals from the poor group than those from the wealthy group could be a consequence of different bed cleaning behaviors between the two groups.     

Prospective randomized multicentre study comparing stapler haemorrhoidopexy with Doppler‐guided transanal haemorrhoid dearterialization for third‐degree haemorrhoids

Aim Doppler‐guided transanal haemorrhoid dearterialization (THD) and stapler haemorrhoidopexy (SH) have been demonstrated to be less painful than the Milligan–Morgan procedure. The aim of this study was to compare the effectiveness of THD vs SH in the treatment of third‐degree haemorrhoids in an equivalent trial. Method One hundred and sixty‐nine patients with third‐degree haemorrhoids were randomized online to receive THD (n = 85) or SH (n = 84) in 10 Colorectal Units in which the staff were well trained in both techniques. The mean follow‐up period was 17 (range 15–20) months. Results Early minor postoperative complications occurred in 30.6% of patients in the THD group and in 32.1% of patients in the SH group. Milder spontaneous pain and pain on defecation were reported in the THD group in the first postoperative week, but this was not statistically significant. Late complications were significantly higher (P = 0.028) in the SH group. Residual haemorrhoids persisted in 12 patients in the THD group and in six patients in the SH group (P = 0.14). Six patients in the SH group and 10 in the THD group underwent further treatment of haemorrhoids (P = 0.34). No differences were found in postoperative incontinence. The obstructed defecation score (ODS) was significantly higher in the SH group (P < 0.02). Improvement in quality of life was similar in both groups. Postoperative in‐hospital stay was 1.14 days in the THD group and 1.31 days in the SH group (P = 0.03). Conclusion Both THD and SH techniques are effective for the treatment of third‐degree haemorrhoids in the medium term. THD has a better cost‐effective ratio and lower (not significant) pain compared with SH. Postoperative pain and recurrence did not differ significantly between the two groups.     

2019年中国科技论文统计与分析简报

【目的】 了解中国科技人员在国内外发表论文情况,为各级管理部门提供决策依据。【方法】 采用国际权威检索数据库《科学引文索引》《工程索引》《科技会议录引文索引》、Scopus数据库、《医学索引》《社会科学引文索引》以及《中国科技论文与引文数据库》的数据,对中国卓越科技论文、中国科技论文数量、学科和地区分布、基金项目论文、国际合著论文和社会科学论文情况进行统计分析。【结果】 2019年中国卓越科技论文数量为38.73万篇,较2018年增加了22.6%;根据《科学引文索引》的数据,2019年中国作者共计发 表49.59万篇论文,连续第11年位居世界第2,仅次于美国;2010—2020年(截至2020年10月),中国论文的总被引频次为3605.71万次,与2018年的统计结果相比,增加了26.7%,位居世界第2;中国平均每篇论文被引用了11.94次,比2018年的统计结果提高了9.3%,但是仍低于世界平均值13.26次/篇。【结论】 近年来,中国科技论文数量迅速增长,论文影响力的提升速度也相对较快,但篇均被引频次与世界平均值相比还有较大差距。     

A benefit/risk approach towards selecting appropriate pharmaceutical dosage forms - An application for paediatric dosage form selection

The design and selection of new pharmaceutical dosage forms involves the careful consideration and balancing of a quality target product profile against technical challenges and development feasibility. Paediatric dosage forms present particular complexity due to the diverse patient population, patient compliance challenges and safety considerations of this vulnerable population. This paper presents a structured framework for assessing the comparative benefits and risks of different pharmaceutical design options against pre-determined criteria relating to (1) efficacy, (2) safety and (3) patient access. This benefit/risk framework has then been applied to three hypothetical, but realistic, scenarios for paediatric dosage forms in order to explore its utility in guiding dosage form design and formulation selection. The approach allows a rigorous, systematic and qualitative assessment of the merits and disadvantages of each dosage form option and helps identify mitigating strategies to modify risk. The application of a weighting and scoring system to the criteria depending on the specific case could further refine the analysis and aid decision-making. In this paper, one case study is scored for illustrative purposes. However, it is acknowledged that in real development scenarios, the generation of actual data considering the very specific situation for the patient/product/developer would come into play to drive decisions on the most appropriate dosage form strategy.