Classical swine fever virus down-regulates endothelial connexin 43 gap junctions

Classical swine fever is a contagious disease of pigs characterized by fatal hemorrhagic fever. Classical swine fever virus (CSFV) induces the expression of pro-inflammatory and pro-coagulant factors of vascular endothelial cells and establishes a long-term infection. This study aimed to understand the effect of CSFV on endothelial connexin 43 (Cx43) expression and gap junctional intercellular coupling (GJIC). Porcine aortic endothelial cells were infected with CSFV at different multiplicity of infection for 48 h. Semi-quantitative RT-PCR, immunoconfocal microscopy, and Western blotting showed that the transcription and translation of Cx43 were reduced, and this was associated with an attenuation of GJIC. This decrease occurred in a time-dependent manner. An ERK inhibitor (PD98059), a JNK inhibitor (SP600125), and proteasome/lysosome inhibitors all significantly reversed the reduction in Cx43 protein levels without any influence on the titer of progeny virus. In addition, CSFV activated ERK and JNK in a time-dependent manner and down-regulated Cx43 promoter activity, mainly through decreased AP2 binding. This effect was primarily caused by the replication of CSFV rather than a consequence of cytokines being induced by CSFV infection of endothelial cells.

Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance. The Da Qing IGT and Diabetes Study

OBJECTIVE

Individuals with impaired glucose tolerance (IGT) have a high risk of developing NIDDM. The purpose of this study was to determine whether diet and exercise interventions in those with IGT may delay the development of NIDDM, i.e., reduce the incidence of NIDDM, and thereby reduce the overall incidence of diabetic complications, such as cardiovascular, renal, and retinal disease, and the excess mortality attributable to these complications.

RESEARCH DESIGN AND METHODS

In 1986, 110,660 men and women from 33 health care clinics in the city of Da Qing, China, were screened for IGT and NIDDM. Of these individuals, 577 were classified (using World Health Organization criteria) as having IGT. Subjects were randomized by clinic into a clinical trial, either to a control group or to one of three active treatment groups: diet only, exercise only, or diet plus exercise. Follow-up evaluation examinations were conducted at 2-year intervals over a 6-year period to identify subjects who developed NIDDM. Cox's proportional hazard analysis was used to determine if the incidence of NIDDM varied by treatment assignment.

RESULTS

The cumulative incidence of diabetes at 6 years was 67.7% (95% CI, 59.8-75.2) in the control group compared with 43.8% (95% CI, 35.5-52.3) in the diet group, 41.1% (95% CI, 33.4-49.4) in the exercise group, and 46.0% (95% CI, 37.3-54.7) in the diet-plus-exercise group (P < 0.05). When analyzed by clinic, each of the active intervention groups differed significantly from the control clinics (P < 0.05). The relative decrease in rate of development of diabetes in the active treatment groups was similar when subjects were stratified as lean or overweight (BMI < or > or = 25 kg/m2). In a proportional hazards analysis adjusted for differences in baseline BMI and fasting glucose, the diet, exercise, and diet-plus-exercise interventions were associated with 31% (P < 0.03), 46% (P < 0.0005), and 42% (P < 0.005) reductions in risk of developing diabetes, respectively.

CONCLUSIONS

Diet and/or exercise interventions led to a significant decrease in the incidence of diabetes over a 6-year period among those with IGT.

Impaired glucose tolerance and its relationship to ECG-indicated coronary heart disease and risk factors among Chinese. Da Qing IGT and diabetes study

OBJECTIVE

To determine the prevalence of IGT and diabetes and identify the occurrence of CVD and its risk factors.

RESEARCH DESIGN AND METHODS

This study was a population-based, cross-sectional study of 110,660 residents, 25-74 yr of age of DaQing, Hei Long Jiang Province, China.

RESULTS

Using 1985 WHO criteria, 577 (5.5/1000) subjects with IGT and 630 (6.0/1000) with newly diagnosed diabetes were identified. In addition, 190 (1.7/1000) with previously known diabetes were identified. Hypertension, obesity, and abnormal albumin excretion were twice as frequent in those with IGT as in 279 men and 240 women of similar age and sex distribution who had normal OGTTs. Plasma cholesterol and TGs were higher, and HDL cholesterol was lower in subjects with IGT than in nondiabetic subjects. Those with IGT had a prevalence of electrocardiographically recognized CHD 9.5-fold greater than the normoglycemic subjects. Subjects with IGT had higher plasma insulin concentrations, but the 1-h insulin-glucose ratio after the 75-g glucose load was lower. In a forward stepwise multiple logistic regression analysis, IGT itself remained an independent factor associated with CHD after adjustment for age, sex, cigarette smoking, plasma cholesterol, BP, and obesity.

CONCLUSIONS

Therefore, in China, IGT may occur with almost as high a frequency as diabetes and is accompanied by an increased frequency of CVD and its risk factors. Estimates from this study indicate that > 12.0% of all ECG-indicated CHD in the Da Qing population occurs in individuals with IGT and NIDDM. The IGT subjects identified in this survey form the cohort for a long-term follow-up and intervention study.

Coronary heart disease and diabetic retinopathy in newly diagnosed diabetes in Da Qing, China: the Da Qing IGT and Diabetes Study

In 1986, 110,660 of 281,589 residents aged 25-74 years in Da Qing, Hei Long Jiang Province of China, were surveyed. Based on the results of a 75-g oral glucose tolerance test, 630 subjects were found to have previously undiagnosed diabetes according to 1985 WHO criteria. Among them, 600 diabetics aged 35-74 years (288 men, 312 women) and 410 non-diabetics of similar age with normal glucose tolerance (207 men, 203 women) were examined to determine the prevalence of retinopathy and coronary heart disease (CHD) and to evaluate associated characteristics. Retinal examinations of 423 newly diagnosed diabetics showed that 15.4% had several microaneurysms and/or small intraretinal haemorrhage, 5.5% soft exudates, 7.1% hard exudates, and 2.3% proliferative retinopathy. Among 220 non-diabetics, 13.6% had one or two microaneurysms and/or small intraretinal haemorrhage, and only 1.4% had a few soft exudates; half of the non-diabetics with retinopathy had hypertension. CHD, according to Minnesota coding (1.1-1.3, 5.1-5.3 and 7.1) of resting electrocardiograms, was ten times more frequent in the diabetics (3.59%) than in the controls (0.32%), after adjusting for age and sex. Multiple regression analysis showed that plasma glucose concentration was a risk factor for retinopathy after adjusting for age, sex, body mass index (BMI), smoking and blood pressure. Two-hour plasma glucose concentration (after adjusting for age, sex, BMI, smoking and blood pressure) and blood pressure (after adjusting for age, sex BMI, smoking and 1-h or 2-h plasma glucose level) were associated with CHD among the diabetics and non-diabetics and among the diabetics alone. Thus, both micro- and macrovascular complications occur frequently in previously undiagnosed Chinese diabetics and the frequency of CHD is markedly increased compared to the low frequency among Chinese non-diabetics.

Protein kinases and membrane protein phosphorylation in normal and abnormal human erythrocytes: variation related to mean cell age

Protein kinase activities and membrane autophosphorylation reactions of normal and abnormal human erythrocytes were analyzed. Erythrocytes from patients with high reticulocytosis due to sickle cell anemia and other disorders (n = 13) exhibited elevated activities of total and membrane-bound cAMP-independent casein kinase and cAMP-stimulated histone kinase. Relative to normal controls (n = 10), the average total activities in these abnormal cells were increased 50% and 81%, respectively. The casein and histone kinase activities of normal and abnormal erythrocytes declined significantly with increasing age and buoyant density in Stractan density gradients. Casein kinase activity was highly correlated (r = 0.88; n = 23) with the percentage of reticulocytes in the fraction, consistent with either a progressive loss of activity in mature erythrocytes or an abrupt decline during reticulocyte maturation. The cAMP-independent and cAMP-stimulated autophosphorylation activities of isolated membranes also declined with increasing erythrocyte age. On average, the initial rate of spectrin labeling was 36% lower in ghosts from Stractan gradient bottom fractions, relative to ghosts from top fractions similarly incubated with gamma-32P-ATP. Incorporation into the "band 4.5 zone" (primarily labeling bands 4.8 and 4.9, mol wt 47,800 and 44,600) was also age-dependent. In membranes of unfractionated sickle cells, spectrin autophosphorylation was within normal limits, while 4.5 zone autophosphorylation was increased. Membranes from high reticulocytosis controls (vitamin B-12 deficiency) exhibited similar autophosphorylation patterns, suggesting that the altered autophosphorylation pattern of sickle cell membranes may be attributed to the predominance of very young cells.