Molecular association in aqueous solutions of high molecular weight poly(N-vinyl-2-pyrrolidone)

A viscosimetric method was used to investigate the molecular association in aqueous solutions of poly(N-vinyl-2-pyrrolidone), (PVP), of molecular weight 700 000. Limiting viscosity numbers [η] and Huggins constants k_H of the polymer solutions were observed to decrease upon addition of denaturing agents such as thiourea and guanidinium sulfate. Guanidinium sulfate was found to be even more effective in its denaturing action as compared to urea and thiourea. The decrease in [η] and k_H values increased with increasing concentrations of the denaturing agents. This behaviour was explained on the basis of the rupture of bridges formed by water molecules among different PVP chains, hydrogen bonding being responsible for these intermolecular associations. While no change in the [η] values was observed for PVP in 2 M thiourea solutions upon increasing the temperature from 25°C to 35 and 45°C, for the same increase in temperature the [η] values of aqueous PVP solutions showed substantial decreases. This is also attributed to the breaking of hydrogen bonds existing between PVP molecules.     

Thrombopoietin receptor (Mpl) expression by megakaryocytes in myeloproliferative disorders

The thrombopoietin receptor (Mpl) is involved in the pathogenesis of chronic myeloproliferative disorders (CMPD). In this study, we determined Mpl expression by bone marrow cells and megakaryocytes in CMPD by applying laser microdissection, real-time RT-PCR, and immunohistochemistry. Mpl mRNA expression was significantly increased up to 9-fold in total bone marrow cells (p < 0.001) and up to 4-fold in megakaryocytes in chronic myeloproliferative disorders (n = 73) compared to normal controls (n = 26, p = 0.01). Immunohistochemistry revealed heterogeneous Mpl expression by megakaryocytes in CMPD with a stronger accentuation in idiopathic myelofibrosis (IMF) in comparison to polycythaemia vera (PV) and essential thrombocythemia (ET). In addition to megakaryocytes, the erythropoietic lineage was prominently labelled by Mpl antiserum, with considerably stronger staining in polycythaemia vera. We conclude that, in CMPD, megakaryocytes and erythroid cells exhibit increased Mpl expression levels which may contribute to the sustained proliferation of both cell lineages in CMPD.     

The prevalence of metabolic syndrome is increased in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis

Purpose

Cardiovascular disease is one of the major causes of mortality in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). Metabolic syndrome (MetS) is associated with increased cardiovascular risk in the normal population. However, MetS in AAV has not been adequately investigated. We aimed to determine MetS prevalence and associated factors in AAV patients.

Methods

Thirty-seven AAV patients and 42 healthy controls were enrolled. MetS was determined by International Diabetes Federation (IDF) and National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII) criteria. The relationship between clinical features of AAV and MetS was also investigated.

Results

MetS was significantly higher in AAV patients than controls by NCEP-ATPIII (51.4% vs. 26.2%, p 0.022) and IDF (62.2% vs. 35.7%, p 0.020). When AAV patients with MetS were compared to those without, there were significant differences in age, CRP, GFR and NT-pro-BNP. Age [58 (13) vs. 50 (8) years p: 0.028], CRP [4.0 (3.6) vs. 3.2 (1.0) mg/l, p 0.021] and NT-pro-BNP [173.5 (343.7) vs. 106.0 (103.0) pg/ml, p 0.013] were significantly higher in AAV patients with MetS than those without; GFR was significantly lower [38 (46) vs. 83 (51) ml/min/1.73 m², p 0.004]. ROC curve analysis showed NT-pro-BNP?>?58.0 ng/ml predicted MetS with 87.1% sensitivity and 46.7% specificity (Area under curve: 0.71, CI 0.536–0.902, p 0.041). Multivariate analysis revealed age [OR (95% CI): 1.180 (1.010–1.370), p 0.039] and NT-pro-BNP?>?58 pg/ml [OR (95% CI): 5.5 (1.02–30.1) p 0.047] were independent predictors of MetS in AAV patients.

Conclusion

MetS is significantly higher in AAV patients than controls and is associated with age and NT-pro-BNP. Screening and treating MetS may improve prognosis in AAV patients.

     

Carbamazepine-induced sperm disorders can be associated with the altered expressions of testicular KCNJ11/miR-let-7a and spermatozoal CFTR/miR-27a

Male infertility is a global health problem, and the underlying molecular mechanisms are not clearly known. Ion channels and microRNAs (miRNAs), known to function in many vital functions in cells, have been shown to play a significant role in male infertility through changes in their expressions. The study aimed to evaluate the alterations of testicular and/or spermatozoal potassium voltage-gated channel subfamily J member 11 (KCNJ11), Cystic fibrosis transmembrane conductance regulator (CFTR), miR-let-7a and miR-27a expressions in carbamazepine-related male infertility. Here, we showed that carbamazepine reduced sperm motility, increased abnormal sperm morphology, and impaired hormonal balance as well as increased relative testis weight and decreased relative seminal vesicle weight. On the other hand, downregulated KCNJ11 and upregulated miR-let-7a expressions were determined in testis (p < .05). Also, downregulated KCNJ11 and upregulated CFTR and miR-27a expressions were found in spermatozoa (p < .05). Interestingly, altered testicular KCNJ11 and miR-let-7a expressions were correlated with decreased sperm motility and elevated sperm tail defect. Besides, spermatozoal CFTR and miR-27a expressions positively correlated with sperm tail defects. The results indicated a significant relationship between ion channel and/or miRNA expression alterations and impaired sperm parameters due to carbamazepine usage.     

Posterior fossa pseudotumour due to viral encephalitis in a child

A 14-year-old boy had a 1-month history of diplopia (due to a VI nerve palsy), motor ataxia and dizziness. Brain MRI showed a 1.5-cm mass posterior to the pons. Histopathological examination of a biopsy specimen showed the lesion to be of viral origin. After 3 months, the ataxia and dizziness had resolved and the MRI findings returned to normal. By 5 months the abducens paralysis had also resolved. Viral encephalitis should be considered in the differential diagnosis of posterior fossa tumours. Received: 20 March 1997 Accepted: 16 April 1997     

The Impact of Mitral Stenosis on Left Atrial Function Assessed by Two‐Dimensional Speckle Tracking Echocardiography

Aims: The aim of this study is to investigate the effect of mitral stenosis (MS) on left atrial (LA) function using two‐dimensional speckle tracking echocardiography (2DSTE). Methods and Results: The study subjects consisted of 52 patients with asymptomatic MS and 52 control subjects. LA function was assessed using prototype speckle tracking software and manual tracking method. Maximal LA volume (LAVmax) and minimal LA volume (LAVmin) and LA volume before atrial contraction (LAVpre‐a) were measured. Using these volumes, LA reservoir, conduit and booster pump fuction parameters were calculated. Indexed LAVmax, LAVmin, and LAVpre‐a measurements via speckle tracking were highly correlated with manual tracing methods in both groups. Expansion index (67.8 ± 36.4 vs. 148.3 ± 44.2), diastolic emptying index (37.7 ± 12.9 vs. 58.0 ± 8.5), passive emptying (37.3 ± 14.1 vs. 70.4 ± 10.4) and passive emptying index (13.3 ± 6.3 vs. 41.3 ± 10.6) were decreased significantly in MS patients (P < 0.001). In contrast active emptying index (62.6 ± 4.1 vs. 29.5 ± 10.1) increased in MS group (P < 0.001) while active emptying (28.1 ± 13.0 vs. 28.3 ± 6.9) remained same among both groups. Conclusions: This is the first study relating LA volumes and function assessed by 2DSTE to MS. 2D speckle tracking analysis of LA volume is relatively easy and provides more detailed information regarding the changes in LA volumes during the cardiac cycle.