Nitric oxide and cyclic GMP as pro- and anti-apoptotic agents

BACKGROUND: Previously we showed that atrial natriuretic peptide (ANP) increases cGMP production in PC12 (sympathetic-neuron-like) cells, cGMP elevations increase survival of hippocampal neurons during glutamate toxicity and ANP-induced cGMP elevations prolongs survival of stressed PC12 cells, all suggesting cGMP mediates anti-apoptotic/pro-survival effects in neural cells. AIM: The objective was to use a new technology, capillary electrophoresis-laser-induced-fluorescence-detector (CE-LIF) to accurately measure nitric oxide (NO)-induced stimulation and ANP/cGMP-induced inhibition of apoptotic DNA fragmentation in PC12 and NG108-15 (cholinergic-neuron-like) cells. METHODS: Apoptotic DNA fragmentation was quantified by CE-LIF. RESULTS: Sodium nitroprusside (SNP, 0.1-1.0 mM, 24 hours), NO donor, increased apoptotic DNA fragmentation in NG108-15 cells, but not PC12 cells (both with serum). In serum-deprived PC12 cells, ANP at 1, 10 and 100 nM inhibited apoptotic DNA fragmentation by 75.8%, 84.7%, and 94.1%, respectively. CONCLUSIONS: The data show that NO at higher levels induces apoptosis in NG108-15 cells, but not PC12 cells, indicating differences in susceptibility to NO-induced toxicity, and that ANP-induced cGMP elevation is a potent and effective inhibitor of apoptosis in PC12 cells. The data suggest that NO-induced cGMP elevations in certain neural cells (e.g. PC12 cells) provide a protective (anti-apoptotic) mechanism that counter-balances the pro-apoptotic actions of NO, thus helping to limit damage caused by NO.     

B23在肝再生和肝细胞增生过程中的表达与移位

目的：用B23蛋白的单克隆抗体研究B23表达在鼠肝大部分切除后再生过程中肝细胞的动态变化,探讨B23作为肝再生和肝细胞增生标记物的可能性。方法：鼠肝大部切除术后第1、2、3、4和7d收取再生肝组织,采用B23的单克隆抗体和Western印迹及免疫组化方法检测B23在不同时间再生肝组织的表达,并与增殖细胞核抗原（PCNA）的表达相比较。结果：B23在静止期肝细胞中几乎检测不到,但在不同时间再生肝组织的表达中既有表达量的变化又有表达位置的变化,在术后1－7d再生肝组织的表达中,B23表达量的增高变化呈近似抛物线样变化,其中第3d表达水平最高,B23表达量的这些变化与PCNA的变化非常相似。B23表达位置的变化从核仁的增强表达（G1－S）开始,进而核浆的表达（S－G2）及胞质和分裂染色体的表达（M）。结论：B23蛋白表达可作为肝再生和肝细胞增生的标记。     

Review of recent advancements in the understanding of primary angle-closure glaucoma

Primary angle-closure glaucoma is a leading cause of blindness worldwide. However, the terminology used for angle-closure in the literature is inconsistent, with inappropriate emphasis on symptomatology. A new nomenclature for primary angle-closure glaucoma focuses on the presence of end-organ damage and limits the use of the term "glaucoma" only for people who have suffered injury to the optic nerve. This review describes the various modalities of treatment for primary angle-closure glaucoma. The role and limitations of laser peripheral iridotomy in the management of the different forms of the disease are summarized. Recent developments have led to improvements in the understanding of the epidemiology, clinical course, and treatment of the condition.     

Prevalence of primary cornea guttata and morphology of corneal endothelium in aging Japanese and Singaporean subjects

The purpose of the present study was to examine, in the aging people, racial and gender differences in the morphology of corneal endothelium as well as the incidence of cornea guttata in two Asian subject groups, one in Singapore and the other in Japan. Four hundred and sixty-five Chinese Singaporeans and 299 Japanese subjects (residents of Monzen-machi, Ishikawa Prefecture) aged 50 years and older were recruited for the study. Corneal endothelial abnormalities were diagnosed with slit-lamp biomicroscopy and specular microscopy. Primary cornea guttata appeared as beaten metal appearance in slit-lamp images and dark regions in specular images. In addition to cornea guttata, corneal endothelial morphology was also analysed with specular microscopy. The mean cell density was 2,808/mm(2) in the Japanese subjects which was significantly higher than the 2,718/mm(2) seen in the Singaporeans (p < 0.001). The incidence of cornea guttata was significantly higher in the Singaporeans than in the Japanese individuals and also higher in women than in men of both racial groups. These differences support not only a racial and a gender factor but also a possible environmental influence.     

Deteriorated housing contributes to high cockroach allergen levels in inner-city households

The high prevalence of childhood asthma in low-income, inner-city populations is not fully understood but has been at least partly attributed to the disproportionate exposures associated with socioeconomic disadvantage. The contribution of indoor allergens to asthma is well documented, but links between socioeconomic disadvantage and indoor allergen levels are not clear. We investigated levels of cockroach allergens (Bla g 2) in a sample of 132 Dominican or African American low-income households with young children in northern Manhattan in New York City (40% were receiving public assistance) to determine whether the distribution of allergens is a function of housing deterioration. Deterioration was measured by the presence and number of physical housing problems (holes in the ceilings and walls, water damage, etc.). More than 50% of the sample had two or more types of housing dilapidation, and 67% of the sample reported cockroach sightings in their homes. Samples of dust were collected from kitchen and bedroom surfaces. We hypothesized that the greater the dilapidation, the higher the allergen levels, independent of income, sociocultural factors, and pest-control methods. In addition, we hypothesized that the homes of families characterized by frequent moves (23.5%) would have higher allergen levels than more stable families. Results showed significant positive associations between housing deterioration and allergen levels in kitchens, after adjusting for income and ethnicity, with independent effects of residential stability (p< 0.05). Bedroom allergen levels were associated with housing instability (p < 0.01) and ethnicity (p< 0.01). Findings demonstrated that indoor household allergen levels are related to degree of household disrepair, after adjusting for individual family attributes, suggesting that social-structural aspects of housing may be appropriate targets for public health interventions designed to reduce allergen exposure.     

Seroprevalence of IgG antibodies against Chlamydia pneumoniae in Chinese,Malays and Asian Indians in Singapore

BACKGROUND: Chlamydia pneumoniae, a bacterium that causes respiratory infections, is probably under-diagnosed. There is also interest in its possible role in the aetiology of coronary heart disease. This is the first population-based seroprevalence survey of C. pneumoniae infection in Singapore. METHODS: A random sample of 1,068 people aged 18-69 years was selected from the participants of the Singapore National Health Survey conducted in 1998. Sera and data on certain clinical measurements and conditions had been collected. IgG antibodies for C. pneumoniae were detected using an indirect microimmunofluorescence test and positivity graded. Seropositivity was defined as IgG titre >/=1:16. RESULTS: There were no statistically significant differences in the prevalence rates of seropositivity to C. pneumoniae for age group 18-69 years among the three ethnic groups, i.e. Chinese (males 76.7%, females 68.3%), Malays (males 75.4%, females 59.1%), and Asian Indians (males 74.6%, females 59.4%). The seropositivity rate for people aged 18-69 years in Singapore was 75.0% for males and 65.5% for females (difference of 9.5%, P < 0.001). In both genders combined, seropositivity increased from 46.5% in the age group 18-29 to reach a plateau of 78.9% in the age group 40-49, which remained stable to 60-69 years. There was no association of seropositivity with smoking, diabetes mellitus, hypertension or body mass index after adjustment for age and gender. CONCLUSION: The high prevalence rates in our study population and the higher rate in males compared to females are consistent with studies from other parts of the world. No significant difference in prevalence rates was observed among Chinese, Malays and Indians. The pattern of rising and levelling off of seropositivity with age suggests that C. pneumoniae infection occurs early in life, and in older ages the high level of seropositivity is probably maintained by re-infections or chronic infections. Chlamydia pneumoniae infection was not found to be associated with the cardiovascular risk factors examined.     

Disease Management by Prevention

Diabetic retinopathy is a significant cause of visual loss in developed countries. Data from epidemiological studies and controlled clinical trials have resulted in treatment strategies, which are highly successful in preventing blindness. These strategies involve measures that require both education and compliance of the individual with diabetes mellitus and the education of physicians and paramedical staff who deliver care to these patients. This paper presents the classification of diabetic retinopathy and the treatment strategies, both the preventive measures and the active treatment modalities used for diabetic retinopathy. Persons with diabetes should be invited from the first day of diagnosis to be active partners working towards the prevention of diabetic complications.The management of patients with diabetes includes essential medical preventive measures such as tight glucose level and blood pressure control and the lowering of serum cholesterol levels to successfully decrease the risk of microvascular complications, namely diabetic retinopathy, neuropathy and nephropathy. Persons with diabetes should also be aware of the importance of screening for diabetic retinopathy and the beneficial effects of timely laser photocoagulation and other surgical interventions.