Interaction of epidermal growth factor, Ca2+, and matrix metalloproteinase-9 in primary keratinocyte migration

Elevations of epidermal growth factor (EGF) and Ca²⁺ concentrations in the wound site are associated with reepithelialization during wound healing. In addition, Ca²⁺ and EGF can both induce increases in matrix metalloproteinase‐9 (MMP‐9) synthesis. However, little is known about the interplay of these events in regulating the migration properties of primary keratinocytes on collagen I, the most abundant extracellular matrix component in the skin. We found that EGF stimulated both chemokinetic and chemotactic migration of primary keratinocytes on collagen I; however, MMP‐9 was required for EGF‐stimulated chemotaxis but not EGF‐stimulated chemokinesis. Calcium at 0.5 mM stimulated chemokinetic migration of keratinocytes. Together, Ca²⁺ and EGF stimulated higher levels of chemokinesis than either stimulus alone. Furthermore, Ca²⁺ could restore the ability of keratinocytes from MMP‐9 null mice to undergo EGF‐stimulated chemotaxis. The phosphatidylinositol‐3 kinase inhibitor LY294002 inhibited both EGF‐ and Ca²⁺‐stimulated chemokinetic migration. In contrast, the MEK inhibitor PD98059 blocked Ca²⁺‐ but not EGF‐stimulated chemokinetic migration of keratinocytes. A combination of PD98059 and LY294002 was required to inhibit Ca²⁺ enhancement of EGF‐stimulated migration completely. Calcium‐stimulated chemokinesis was completely blocked by either the protein kinase C‐α inhibitor Gö6976 or the src/fyn inhibitor PP2. Using primary keratinocytes, our results showed how the combined action of Ca²⁺, EGF, and MMP‐9 regulated the contributions of extracellular‐regulated kinase and phosphatidylinositol‐3 kinase toward chemokinetic and chemotactic migration of keratinocytes.     

Variation of multifocal electroretinogram with axial length

INTRODUCTION: The first-order kernel response of multifocal electroretinogram (mfERG) decreases in myopia. A recent study indicates that the flash ERG is also reduced with increased axial length. The aim of this study was to investigate the variations in the first-order response (K1) and the first slice of second-order response (K2.1) across the retina for different axial lengths. METHODS: Thirty healthy subjects with axial length from 23.72 to 28.13 mm (spherical equivalent refractive errors from plano to -10.50 D) were recruited for mfERG measurement using VERIS 4.0. All subjects were fully corrected after cycloplegic refraction and pupils were dilated prior to mfERG recording. There is one trough, n1, and one peak, p1, in the K1 response and three troughs, n1, n2, n3, and three peaks, p1, p2, p3, in the K2.1 response. The amplitudes and implicit times of K1 and K2.1 responses were analysed to determine the characteristic of the responses across retina and the correlation to axial length. RESULTS: The amplitudes of p1 (in the first-order kernel-K1) decreased in the central region and the paracentral region (ring 3) as the axial length increased. The central retinal region showed high rates of reduction in both n1 and p1 (in K1). The amplitudes of n1p1 and n2p2 (in the first slice of the second-order kernel-K2.1) were reduced in the paracentral region (from ring 2 to ring 5) as axial length increased. The average n1 and p1 in K1, and n1p1 and n2p2 in K2.1 mfERG responses are decreased in amplitude by 6-10% per millimetre elongation of axial length. CONCLUSION: Eyes with longer axial lengths, usually with high myopia, have a weaker mfERG response and this attenuation is across the measured retina (from central to paracentral regions) but different kernel responses show a different pattern of attenuation at different retinal eccentricities. The weaker mfERG responses may be related to the morphological changes associated with increased axial length.     

Progressive resistance training and nutrition in renal failure.

Nutrition and exercise are an integral part of the medical management of many chronic and complex conditions. They are interrelated and share many common metabolic pathways that may affect disease processes and their management. In nephrology, nutritional interventions have been relatively well studied and are recommended in many evidence-based clinical practice guidelines for managing people with chronic kidney disease (CKD). Over the past 20 years, growing evidence has suggested that aerobic exercise interventions are efficacious, and that the rationale for progressive resistance training (PRT) is strong, particularly in this population, despite a more limited evidence base to date. In the small number of clinical trials that have included patients with CKD, PRT programs have proved safe, feasible to administer, and efficacious. They have been shown to improve clinical, physical, and functional outcomes.     

Suicide and unemployment: what are the missing links?

The suicide rate has been paralleled by an upward trend of unemployment in Hong Kong since 1997. This study aims to explore the unknown suicide-related factors among the unemployed. This information is useful in developing culturally specific suicide prevention initiatives related to unemployment. Seventy-six suicide deceased and 15 life subjects who were unemployed were selected from a previous psychological autopsy study. Logistic regression models were employed to estimate the relative suicide risks among the unemployed people. Among the unemployed, the suicide deceased were more likely to be male, had suffered from psychiatric illness, and had attempted suicide before. They also had acquired less competent social problem solving skills. Comparison with a small control group creates a generalizability problem. Suicide prevention for the unemployed could be done through mental health awareness programs; problem-solving skills training for attempters and males; and vocational training and job opportunities for discharged psychiatric patients and rehabilitees.     

Laparoscopic repair of recurrent childhood inguinal hernias after open herniotomy

Background Open repair of recurrent paediatric inguinal hernias (IH) is difficult and there is definite risk of damaging the vas deferens and testicular vessels during dissection of the previous open herniotomy field. Laparoscopic repair (LR) has the benefit of avoiding the previous operative site. Method Records of patients with recurrent IH that had LR after open repair were reviewed and evaluated retrospectively. The results were compared with data from cases in which the LR method was used in the initial IH repair. Results From September 2002 to October 2005, four boys and one girl (mean age 58.8 months) were treated in our institution for recurrent IH after open repair. Operative time, success rate and complications did not show any statistically significant difference when compared with our previous prospectively collected data for primary repairs. Conclusion Laparoscopic repair is the preferred operation for recurrent childhood IH after open repair.     

Scale-up of Adhesive Transdermal Drug Delivery Systems

Pharmaceutical Research -     

中国内地城市和香港9～18岁学生心肺耐力及肌肉素质的比较研究

为了比较中国内地城市和香港青少年儿童的心肺耐力和肌肉素质，对两地的青少年儿童体质调查数据进行了比较研究。结果发现：内地各年龄组男女生的心肺耐力均优于香港同龄者；香港青少年儿童的肌肉素质除立定跳远外，其他项目的成绩均弱于内地青少年儿童。提示：随着生活水平的提高，应重视青少年儿童对体育活动的参与。