Down-regulation of inducible nitric oxide synthase (iNOS) in rat with congenital hydronephrosis

BACKGROUND: Most of our knowledge concerning obstructive uropathy has been derived mainly from surgically manipulated animal models, and the pathogenesis of congenital obstructive hydronephrosis is not fully elucidated. Nitric oxide (NO) acts as an important biological modulator with diverse physiological functions, which can be either toxic or protective depending on the situation. NO is synthesized from l-arginine by nitric oxide synthase, and in the kidney iNOS is expressed spontaneously. The aim of our study is to investigate the expression of iNOS protein and its relationship with tubulointerstitial fibrosis and tubular cell apoptosis in congenital hydronephrosis. METHODS: We conducted histological studies on 18 kidneys of six-week-old-rats from an inbred colony of congenital hydronephrosis with reference to the histological grading of the affected kidney, tubulointerstitial fibrosis, renal tubular atrophy, and tubular cell apoptosis. Renal transforming growth factor-beta1 (TGF-beta1) level was determined by a sandwich ELISA assay and the expression of iNOS was analyzed by western blotting. RESULTS: Most of the hydronephrotic kidneys were markedly enlarged with dilatation of the collecting system, parenchymal thinning, tubular atrophy, interstitial infiltration and fibrosis. Renal TGF-beta1 level was higher in hydronephrotic kidneys than normal control kidneys (364.81 +/- 52.60 vs. 221.19 +/- 22.53 pg/mg protein, P < 0.05). Tubular apoptotic score in hydronephrotic kidneys was also significantly higher than in the normal control kidneys (1.97 +/- 0.42 vs. 0.14 +/- 0.02/HPF, P < 0.01). The expression of iNOS protein was lower in the affected kidneys compared with the normal control kidneys (8.79 +/- 0.78 vs. 14.00 +/- 0.83 arbitrary unit, P < 0.01). There was a negative correlation between iNOS expression and histological grading in congenital hydronephrosis. The iNOS expression also correlated negatively with renal interstitial fibrosis, TGF-beta1 level and tubular cell apoptosis. CONCLUSION: Our study confirmed the down-regulation of iNOS expression in affected kidneys from rats with congenital hydronephrosis, in which the cytoprotective effect of NO may be lost or weakened.     

A protease inhibitor attenuates gastric erosions and microcirculatory disturbance in the early period after thermal injury in rats

The effects of camostat mesilate, a synthetic serine protease inhibitor on gastric microcirculation and active oxygen species generated by leucocytes from the gastric and jugular veins in the early period after thermal injury were assessed. Male Wistar rats were anaesthetized and a 30% full skin-thickness dorsal burn was inflicted. Camostat mesilate (100 mg/kg) was dissolved in distilled water and administered orally to rats 40 min before thermal injury (the camostat group). The control animals (the vehicle group) were administered distilled water orally. Rolling leucocytes as well as Monastral blue B deposits in venules were observed using in vivo microscopy. Active oxygen species were measured by chemiluminescence. Camostat mesilate decreased the total length of gastric erosion, venular deposits of Monastral blue B, and rolling of leucocytes in venules, and relatively increased luminol-dependent chemiluminescence activity generated by zymosan-stimulated leucocytes 15 min after thermal injury. These results suggest that serine proteases are involved in the formation of gastric erosions and gastric microcirculatory disturbance in the early period after thermal injury.     

人骨髓间质干细胞体外扩增和向内皮细胞定向诱导分化的研究

目的：体外分离、扩增成人骨髓间质干细胞（MSCs）和向内皮细胞（ECs）定向诱导分化，开辟心血管组织工程种子细胞的新来源。 方法： 采用Percoll(1 073 g/L)从正常成人骨髓中分离出MSCs，纯化和扩增后流式细胞仪鉴定其纯度；用血管内皮生长因子(VEGF)诱导MSCs向ECs分化，Ⅷ因子(vWF)免疫组化和透射电镜(TEM)鉴定细胞性质。 结果： 5.0×105个MSCs在体外扩增15代后，获得8.0×1012个MSCs，扩增了约1.6×107倍；MSCs在加入VEGF诱导培养大约14-21 d，80%-90%的诱导细胞对Ⅷ因子相关抗原呈阳性反应；TEM可观察到胞浆内有Weible-palade小体，证实为ECs。 结论： 成人骨髓MSCs在体外具有定向诱导分化为ECs的潜能，这为心脏组织工程瓣体外构建, 尤其是在小儿先天性心脏病组织工程研究中种子细胞的来源提供了可能性。     

反相高效液相色谱测定丹参注射剂的三种有效成分

本文用反相高效液相色谱法,采用离子抑制技术分离了丹参注射剂中三种有效成分:丹参素、原儿茶醛、原儿茶酸。并用外标法测定了它们在丹参注射液和复方丹参注射液中的含量。考察了Waters公司分析柱(3.9×300 mm)和径向加压柱(8×100 mm),以及国产色谱柱(5×150mm)分析样品,均能获得满意的结果。比较了用多通道紫外吸收检测器和254nm固定波长紫外检测器测定样品时灵敏度的差异。     

Comparison of the effects of pentagastrin and meal-stimulated gastrin on plasma calcitonin in normal man

We compared the effects of exogenous pentagastrin and meal-stimulated gastrin on plasma immunoreactive calcitonin (iCT) in various studies of 13 normal adult men. Bolus intravenous injection of pentagastrin (0.5 μg/kg) produced increases of iCT in 8 of 9 men. There was a linearly increasing response of iCT concentrations to increasing doses of pentagastrin (0.0625, 0.125, 0.25, and 0.5 μg/kg) and to achieved serum immunoreactive pentagastrin concentrations (r=0.72, P<0.01). To determine the effects of endogenous gastrin upon peripheral iCT concentrations, we measured serum immunoreactive gastrin (iG) and plasma iCT in four men at frequent intervals for 240 min after ingestion of low-(100 mg) and high- (400 mg) calcium meals. Serum iG increased in all subjects, with a peak at ～30 min. However, plasma iCT levels were unchanged from basal throughout the study. The increase of pentagastrin (0.3 pmol/ml) which caused a barely detectable increase of iCT was five-to tenfold greater than the mean maximal increases of gastrin after low- and high-calcium meals (0.04 and 0.06 pmol/ml, respectively). These results suggest that increases of plasma iCT concentrations after administration of pentagastrin in man reflect pharmacologic phenomena and that postprandial gastrin secretion may be insufficient to affect peripheral iCT concentrations.     

Cardiopulmonary exercise variables in diastolic versus systolic heart failure

The response to cardiopulmonary exercise (CPX) in patients with heart failure (HF) with normal left ventricular (LV) ejection fractions (EFs) is not well characterized. To determine if CPX testing could distinguish between patients with HF with normal EFs (>50%; i.e., diastolic HF) and those with decreased EFs (> or =50%; i.e., systolic HF), CPX responses were compared between 185 patients with systolic HF (79% men, mean age 62.6 +/- 10.9 years) and 43 with diastolic HF (54% men, mean age 67.4 +/- 9.8 years) enrolled in a phase II multicenter clinical trial. All patients were evaluated with echocardiography and a standardized CPX test as part of the trial. CPX variables, including oxygen uptake at peak exercise (peak VO(2)) and the slope of the ventilation/carbon dioxide production ratio (VE/VCO(2)), were determined and analyzed by core laboratory personnel. Echocardiographic measurements included the LV EF, the E/A ratio, filling time, cavity volumes, right ventricular function, and mitral regurgitation. Patients in the diastolic HF group tended to be older (p <0.08), with more women (p <0.006) and with greater body mass indexes (p <0.02), than those in the systolic HF group. There was no significant difference in the use of beta blockers or the incidence of coronary artery disease. Patients with diastolic HF had decreased E/A ratios (0.9 +/- 0.4 vs 1.4 +/- 1.1, p <0.02, diastolic HF vs systolic HF) and increased filling times (30.4 +/- 3.2 vs 26.5 +/- 4.7 ms, p <0.01, diastolic HF vs systolic HF). No significant differences in peak VO(2) (14.4 +/- 1.9 vs 15.6 +/- 3.2 ml/kg/min, p = 0.06, diastolic HF vs systolic HF) were observed. The VE/VCO(2) ratios for the 2 groups were abnormal and comparable (32 2 +/- 7.5 vs 34.0 +/- 8.3, p = 0.3, diastolic HF vs systolic HF). In conclusion, the CPX response in patients with diastolic HF and systolic HF is markedly abnormal and indistinguishable with regard to peak VO(2) and ventilation despite marked differences in the LV EF.     

Carotid atherosclerosis and right ventricular diastolic dysfunction in a sample of hypertensive Nigerian patients

Aim

To determine the association of carotid atherosclerosis and right ventricular diastolic dysfunction (DD) among treated hypertensive Nigerian patients.

Methods

This was a single center cross-sectional study performed at the Cardiology Clinic of LAUTECH Teaching Hospital, Ogbomoso, Nigeria between January and December 2012. The study included 122 hypertensive Nigerians (mean age, 57.3 ± 14.7 years, 36.9% women). Patients’ clinical, demographic, and echocardiographic parameters were obtained. Diastolic dysfunction was assessed with the trans-tricuspid Doppler flow.

Results

Patients with DD were significantly older than those with normal diastolic function. Mean and maximum carotid intima media thickness measurements were significantly higher among patients with right ventricular DD than in those with normal diastolic function. Mean systolic blood pressure (148.3 ± 31.9 vs 128.0 ± 2.8 mm Hg, P = 0.049) and interventricular septal thickness in diastole (12.8 ± 2.3 vs 11.6 ± 2.8mm, P = 0.048) were significantly higher and tricuspid annular pulmonary systolic excursion (33.6 ± 4.9 vs 23.0 ± 4.2 mm, P = 0.035) was significantly lower in patients with right ventricular DD than in those with normal diastolic function. Carotid intima media thickness measurements were correlated with early trans-tricuspid Doppler flow and early transtricuspid diastolic flow/late right atrial transtricupsid diastolic flow ratio.

Conclusion

Right ventricular DD in hypertensive patients was significantly correlated with increased carotid atherosclerosis. Carotid intima media thickness measurements may therefore be a surrogate marker for DD in hypertensive subjects.Systemic hypertension has been shown to be associated with right ventricular abnormalities in both morphology and function. Right ventricular diastolic dysfunction (DD) may be an early indicator of hypertensive heart disease accompanying left ventricular DD (1-3). It can be diagnosed by various means including the ratio of early and late trans-tricuspid Doppler inflow velocities and tissue Doppler velocities.Atherosclerosis is the underlying factor for many cases of cardiovascular morbidity and mortality (4). A useful surrogate marker for carotid atherosclerosis is carotid intima media thickness (5). This parameter reflects the severity of thickening/atherosclerosis of the major arteries and is directly linked with the severity of hypertension and target organ damage associated with hypertension (2,4). DD is a typical part of the cardiovascular risk spectrum with increased risk for accelerating progressive cardiac dysfunction (6). However, it is still not known whether carotid intima media thickness, which has been shown to correlate with many conventional cardiovascular risk factors, is associated with right ventricular DD, especially among Africans (7). This study aims to determine the association between right ventricular DD and carotid intima media thickness in a sample of Nigerian hypertensive patients.     

How does Helicobacter pylori cause duodenal ulcer disease: The bug, the host, or both?

Abstract Helicobacter pylori infection is the most common cause of duodenal ulcer disease, yet duodenal ulcer is an uncommon outcome of H. pylori infection. We reviewed the possible explanations such as differences in the host or in the strain of H. pylori. Host factors reviewed included genetic susceptibility to H. pylori infection and excess gastric acid secretion. The role of potential H. pylori virulence factors not present in all strains such as the cagA gene and the results of other molecular methods to identify disease-specific differences among isolates was also reviewed. Although cure of H. pylori infection resolves gastrin releasing peptide stimulated acid secretion there was no change in parietal cell mass. Twin studies have shown genetic differences in H. pylori susceptibility. There was no difference in the prevalence of the cagA gene between H. pylori infected asymptomatic volunteers and duodenal ulcer patients ( P = 1.0). DNA-DNA hybridization of whole genomic DNA in solution and cluster analysis of rep-PCR genomic DNA fingerprints suggest that isolates from patients with duodenal ulcer disease are different from those obtained from individuals with asymptomatic gastritis. Cluster analysis of the rep-PCR DNA fingerprints revealed two major groups of the strains; one set consisted of strains from patients with duodenal ulcer disease and the second cluster consisted largely of strains from individuals with asymptomatic gastritis. Recent molecular studies suggest that disease-specific cell lineages or strains may exist among H. pylori isolates leading to the various outcomes observed in patients with H. pylori infection.