Household smoking practices of parents with young children, and predictors of poor household smoking practices

Objectives: Household smoking practices of parents have a major impact on the health of their young children. This study examined the characteristics and household smoking practices of parents with children aged 4-5 years, and identified the predictive factors of poor household smoking practices among Chinese parents in Hong Kong. Study design: Cross-sectional survey. Methods: Smoking parents with young children from a 1997 birth cohort were re-contacted for a telephone interview to assess their household smoking practices. Results: Among 1149 smoking parents from 1049 families, 898 (85.6%) parents smoked at home. Of these, 339 (37.8%) parents reported smoking at home but not near (i.e. within 3 metres) their children, and 559 (62.2%) reported that they smoked at home without any restrictions. Logistic regression revealed that the predictors of poor household smoking practices were: smoking mother [odds ratio (OR) 4.92, P < 0.001]; children born with normal birth weight (OR 2.62, P < 0.05); having more than one child (OR 1.70, P = 0.01); being a daily smoker (OR 18.96, P < 0.0001); smoking ≥ 11 cigarettes per day (OR 3.10, P < 0.0001); having a higher Fagerstorm nicotine dependence score (OR 4.57-4.86, P < 0.01); and having a smoking partner (OR 2.78, P < 0.05). Conclusions: A high proportion of smoking parents with young children display poor smoking practices at home. It is of the utmost importance that community education and smoking cessation services are targeted at these smoking parents to promote smoke-free families. © 2008 The Royal Institute of Public Health.link_to_subscribed_fulltex

The 14-kDa Dynein Light Chain-Family Protein Dlc1 Is Required for Regular Oscillatory Nuclear Movement and Efficient Recombination during Meiotic Prophase in Fission Yeast

A Schizosaccharomyces pombe spindle pole body (SPB) protein interacts in a two-hybrid system with Dlc1, which belongs to the 14-kDa Tctex-1 dynein light chain family. Green fluorescent protein-tagged Dlc1 accumulated at the SPB throughout the life cycle. During meiotic prophase, Dlc1 was present along astral microtubules and microtubule-anchoring sites on the cell cortex, reminiscent of the cytoplasmic dynein heavy chain Dhc1. In a dlc1-null mutant, Dhc1-dependent nuclear movement in meiotic prophase became irregular in its duration and direction. Dhc1 protein was displaced from the cortex anchors and the formation of microtubule bundle(s) that guide nuclear movement was impaired in the mutant. Meiotic recombination in the dlc1 mutant was reduced to levels similar to that in the dhc1 mutant. Dlc1 and Dhc1 also have roles in karyogamy and rDNA relocation during the sexual phase. Strains mutated in both the dlc1 and dhc1 loci displayed more severe defects in recombination, karyogamy, and sporulation than in either single mutant alone, suggesting that Dlc1 is involved in nuclear events that are independent of Dhc1. S. pombe contains a homolog of the 8-kDa dynein light chain, Dlc2. This class of dynein light chain, however, is not essential in either the vegetative or sexual phases

Regulation of Sodium Channel Activity by Capping of Actin Filaments

Ion transport in various tissues can be regulated by the cortical actin cytoskeleton. Specifically, involvement of actin dynamics in the regulation of nonvoltage-gated sodium channels has been shown. Herein, inside-out patch clamp experiments were performed to study the effect of the heterodimeric actin capping protein CapZ on sodium channel regulation in leukemia K562 cells. The channels were activated by cytochalasin-induced disruption of actin filaments and inactivated by G-actin under ionic conditions promoting rapid actin polymerization. CapZ had no direct effect on channel activity. However, being added together with G-actin, CapZ prevented actin-induced channel inactivation, and this effect occurred at CapZ/actin molar ratios from 1:5 to 1:100. When actin was allowed to polymerize at the plasma membrane to induce partial channel inactivation, subsequent addition of CapZ restored the channel activity. These results can be explained by CapZ-induced inhibition of further assembly of actin filaments at the plasma membrane due to the modification of actin dynamics by CapZ. No effect on the channel activity was observed in response to F-actin, confirming that the mechanism of channel inactivation does not involve interaction of the channel with preformed filaments. Our data show that actin-capping protein can participate in the cytoskeleton-associated regulation of sodium transport in nonexcitable cells