Le Forum, Vol. 45 #4

https://digitalcommons.library.umaine.edu/francoamericain_forum/1109/thumbnail.jp

Hemocompatibility of Silicon-Based Substrates for Biomedical Implant Applications

Silicon membranes with highly uniform nanopore sizes fabricated using microelectromechanical systems (MEMS) technology allow for the development of miniaturized implants such as those needed for renal replacement therapies. However, the blood compatibility of silicon has thus far been an unresolved issue in the use of these substrates in implantable biomedical devices. We report the results of hemocompatibility studies using bare silicon, polysilicon, and modified silicon substrates. The surface modifications tested have been shown to reduce protein and/or platelet adhesion, thus potentially improving biocompatibility of silicon. Hemocompatibility was evaluated under four categories—coagulation (thrombin–antithrombin complex, TAT generation), complement activation (complement protein, C3a production), platelet activation (P-selectin, CD62P expression), and platelet adhesion. Our tests revealed that all silicon substrates display low coagulation and complement activation, comparable to that of Teflon and stainless steel, two materials commonly used in medical implants, and significantly lower than that of diethylaminoethyl (DEAE) cellulose, a polymer used in dialysis membranes. Unmodified silicon and polysilicon showed significant platelet attachment; however, the surface modifications on silicon reduced platelet adhesion and activation to levels comparable to that on Teflon. These results suggest that surface-modified silicon substrates are viable for the development of miniaturized renal replacement systems

An investigation of the smoking behaviours of parents before, during and after the birth of their children in Taiwan

[[abstract]]Background: Although many studies have investigated the negative effects of parental smoking on children and Taiwan has started campaigns to promote smoke-free homes, little is known about the smoking behaviours of Taiwanese parents during the childbearing period. To help fill the gap, this study investigated Taiwanese parents' smoking behaviours before, during and after the birth of their children, particularly focusing on smoking cessation during pregnancy and relapse after childbirth. Methods: We used data from the Survey of Health Status of Women and Children, conducted by Taiwan's National Health Research Institutes in 2000. After excluding survey respondents with missing information about their smoking behaviours, our sample consisted of 3,109 women who were married at the time of interview and had at least one childbearing experience between March 1, 1995 and February 28, 1999. Data on parental smoking behaviour in the six months before pregnancy, during pregnancy, and in the first year after childbirth were extracted from the survey and analysed by descriptive statistics as well as logistic regression. Results: Four percent of the mothers and sixty percent of the fathers smoked before the conception of their first child. The educational attainment and occupation of the parents were associated with their smoking status before the first pregnancy in the family. Over 80% of smoking mothers did not quit during pregnancy, and almost all of the smoking fathers continued tobacco use while their partners were pregnant. Over two thirds of the women who stopped smoking during their pregnancies relapsed soon after childbirth. Very few smoking men stopped tobacco use while their partners were pregnant, and over a half of those who quit started to smoke again soon after their children were born. Conclusion: Among Taiwanese women who had childbearing experiences in the late 1990s, few smoked. Of those who smoked, few quit during pregnancy. Most of those who quit relapsed in the first year after childbirth. The smoking prevalence was high among the husbands of these Taiwanese women, and almost all of these smoking fathers continued tobacco use while their partners were pregnant. It is important to advocate the benefits of a smoke-free home to Taiwanese parents-to-be and parents with young children, especially the fathers. The government should take advantage of its free prenatal care and well-child care services to do this. In addition to educational campaigns through the media, the government can request physicians to promote smoke-free homes when they deliver prenatal care and well-child care. This could help reduce young children's health risks from their mothers' smoking during pregnancy and second-hand smoke at home

Robot-assisted gastrectomy and oesophagectomy for cancer

Background: Robot-assisted surgery is a technically feasible alternative to open and laparoscopic surgery, which is being more frequently used in general surgery. We undertook this review to investigate whether robotic assistance provides a significant benefit for oesophagogastric cancer surgery. Methods: Electronic databases were searched for original English-language publications for robotic-assisted gastrectomy and oesophagectomy between January 1990 and October 2013. Results: Sixty-one publications were included. Thirty-five included gastrectomy, 31 included oesophagectomy and five included both operations. Several publications suggest that robot-assisted subtotal gastrectomy can be as safe and effective as an open or laparoscopic procedure, with equal outcomes with regard to the number of lymph nodes resected, overall morbidity and perioperative mortality, and length of hospital stay. Robotic assistance is associated with longer operation times but also with less blood loss in some reports. A significant benefit for robotic assistance has not been shown for the more extensive operations of oesophagectomy or total gastrectomy with D2-lymphadenectomy. There are very few oncologic data regarding local recurrence or long-term survival for any of the robotic operations. Conclusions: No significant differences in morbidity, mortality or number of lymph node harvested have been shown between robot-assisted and laparoscopic gastrectomy or oesophagectomy. Robotic surgery, with its relatively short learning curve, may facilitate reproducible minimally invasive surgery in this field but operation times are reportedly longer and cost differences remain unclear. Randomized trials with oncologic outcomes and cost comparisons are needed

Corporate Governance in Latin America

This paper analyzes recent trends of Latin America's institutional development regarding investor protection. In spite of the underdevelopment of the region's financial markets, there is slow movement towards legal reforms intended to protect investors and make regional markets more attractive to investors; current inadequacies in the region's legal institution's generate high levels of ownership concentration, poor access to external equity financing, and narrow equity markets. The evidence in this paper, based on firm-level data for six countries, shows that, like legal protection of investors, appropriate firm-level corporate governance is linked to lower costs for capital, better valuation, performance, and dividend payments across countries. Firms can compensate for their countries' legal deficiencies by distinguishing themselves through improved corporate governance practices, thus increasing transparency and limiting potential conflict between large and minority shareholders. Firms can additionally look for capital by issuing ADRs, as they have in recent years, although this practice undermines local capital markets. In the end, firms and regulators must improve their governance structures and shareholder protections if they are to meet the improved benchmarks of developed nations brought about by Asian, European, and U.S. scandals in recent years

Renal artery sympathetic denervation:observations from the UK experience

Background: Renal denervation (RDN) may lower blood pressure (BP); however, it is unclear whether medication changes may be confounding results. Furthermore, limited data exist on pattern of ambulatory blood pressure (ABP) response—particularly in those prescribed aldosterone antagonists at the time of RDN. Methods: We examined all patients treated with RDN for treatment-resistant hypertension in 18 UK centres. Results: Results from 253 patients treated with five technologies are shown. Pre-procedural mean office BP (OBP) was 185/102 mmHg (SD 26/19; n = 253) and mean daytime ABP was 170/98 mmHg (SD 22/16; n = 186). Median number of antihypertensive drugs was 5.0: 96 % ACEi/ARB; 86 % thiazide/loop diuretic and 55 % aldosterone antagonist. OBP, available in 90 % at 11 months follow-up, was 163/93 mmHg (reduction of 22/9 mmHg). ABP, available in 70 % at 8.5 months follow-up, was 158/91 mmHg (fall of 12/7 mmHg). Mean drug changes post RDN were: 0.36 drugs added, 0.91 withdrawn. Dose changes appeared neutral. Quartile analysis by starting ABP showed mean reductions in systolic ABP after RDN of: 0.4; 6.5; 14.5 and 22.1 mmHg, respectively (p < 0.001 for trend). Use of aldosterone antagonist did not predict response (p < 0.2). Conclusion: In 253 patients treated with RDN, office BP fell by 22/9 mmHg. Ambulatory BP fell by 12/7 mmHg, though little response was seen in the lowermost quartile of starting blood pressure. Fall in BP was not explained by medication changes and aldosterone antagonist use did not affect response