The Forgotten Variable of Shear Stress in Mitral Annular Calcification: Whole Blood Viscosity

Objective

The aim of this research was to assess the relationship between mitral annular calcification (MAC) and whole blood viscosity (WBV).

Subjects and Methods

A total of 184 patients with MAC and 133 patients without MAC were enrolled in the study. The WBV was calculated with a confirmed formulation using the hematocrit and total plasma protein at a low shear rate (LSR) and high shear rate (HSR). Early diastolic mitral annular velocity (Ea) and late diastolic mitral annular velocity (Aa) were measured using pulse Doppler tissue echocardiography. Pearson''s correlation analysis was performed to assess the relationship between WBV and mitral annular motion velocities. The effects of different variables on the occurrence of MAC were assessed in univariate and multivariate logistic regression analysis.

Results

In patients with MAC, WBV values were significantly higher at HSR (18.04 ± 0.84 vs. 17.25 ± 0.96 208 s^-1, p < 0.001) and at LSR (78.0 ± 14.2 vs. 61.9 ± 17.1 0.5 s^-1, p < 0.001). The WBV at HSR and LSR were significantly correlated with Ea (r = −0.477, p < 0.001; r = −0.385, p < 0.001, respectively) and Aa (r = −0.544, p < 0.001; r = −0.323, p < 0.001, respectively). Multivariate analysis showed that WBV of both shear rates was an independent predictor of MAC. Using the ROC curve, a cut-off value of 70.1 for WBV at LSR had a sensitivity of 83.7% and a specificity of 73.7% (AUC 0.785, p < 0.001) and a WBV cut-off value of 17.5 at HSR had a sensitivity of 79.6% and a specificity of 71.4% (AUC 0.761, p < 0.001) for the prediction of MAC.

Conclusion

Patients with MAC had significantly higher WBV, which independently predicted the presence of MAC. WBV had an inverse correlation with mitral annular motion velocities, indicating that a higher WBV may lead to greater limitation in annular motion and, thus, more calcification.Key Words: Mitral valve calcification, Shear stress, Blood viscosity     

Evaluation of 28 cases of mucormycosis

Mucormycosis is a rare but invasive fungal disease with high mortality. The present study aimed to retrospectively investigate the demographic characteristics, as well as the clinical, radiological and laboratory features and the results of treatment, in the patients followed in our hospital because of mucormycosis. The present study retrospectively evaluated 28 cases, which were followed in our hospital because of mucormycosis between January 2002 and July 2013. The clinical form was rhinocerebral in 27 cases (rhinoorbital in 12, nasal in 8 and rhinoorbitocerebral in 7) and disseminated in one case. With regard to predisposing factors, diabetes mellitus (n = 20), haematological malignancy (n = 6) and chronic renal insufficiency (n = 5) were the leading concomitant diseases. Seventeen (61%) of 28 cases showed atypical clinical picture. With regard to the therapeutic outcomes; it was found that 14 (50%) cases died and six cases recovered with sequel. Today, when particularly the prevalence of immunosuppressive diseases and conditions are gradually increasing, the incidence of mucormycosis is also increased. Considering that the majority of our cases had atypical clinical involvement and complications, being familiar with the characteristics of this disease could be life‐saving together with early diagnosis and treatment.     

Lysozyme Activity in the Plasma of Rodents Infected With Their Homologous Trypanosomes

Background

In this study the concentration of lysozyme in blood plasma of Microtus agrestis, Clethrinomys glareolus, Apodemus sylvaticus, BK rats and outbred white mice before and after infection with culture forms of Trypanosoma microti, T, evotomys, T. grosi, T. lewisi and T. musculi respectively was measured.

Methods

Blood samples of rodents, Microtus agrestis, Clethrionomys glareolus, Apodemus sylvaticus, BK rats and outbred mice infected with T. microti, T. evotomys, T. grosi, T. lewisi and T. musculi respectively were collected in heparinized micro- tubes immediately before inoculation and 3, 6, 12, 24, 48, 96 and more than 400 days after intra- perituneal inoculation with 5×10⁵of their homologous trypanosome parasites of which more than half were metacyclic trypomastigote in 0.2 ml of culture medium. Micro- tubes were centrifuged and plasma samples were separated and the lysozyme activity was measured by the agar method.

Results

Levels of lysozyme rose rapidly three to six days after the inoculation to ten to twenty than their pre- infection levels. They then gradually decreased, although after more than one year they were still two to ten folds higher than controls. The highest level measured occurred in rats infected with T. lewisi and the lowest in A. sylvaticus infected with T. grosi. After one year the highest concentration of lysozyme was in mice infected with T. musculi and lowest in A. sylvaticus.

Conclusion

Persistent enhanced lysozyme levels may prevent re- infection with trypanosomes.     

Decrease in subunit aggregation of phosphoribosylpyrophosphate synthetase: a mechanism for decreased nucleotide concentrations in pyruvate kinase-deficient human erythrocytes

Pyruvate kinase (PK)-deficient RBCs have several unexplained metabolic abnormalities, such as decreased concentrations of total adenine nucleotides (AMP, ADP, and ATP) and total (oxidized and reduced) nicotinamide adenine dinucleotide (NAD). Because 5-phosphoribosyl-1- pyrophosphate (PRPP) is an intermediate in the synthesis of adenine nucleotides and NAD, we investigated PRPP synthetase (PRPPS), the enzyme responsible for PRPP synthesis. This enzyme is regulated, in part, by changes in its state of subunit aggregation. The proportion of aggregated PRPPS can be altered in vitro by ATP and 2,3- diphosphoglycerate (DPG). Because PK-deficient RBCs have decreased ATP and increased DPG concentrations, we examined the state of subunit aggregation of PRPPS in RBCs from normal and PK-deficient subjects, using gel permeation chromatography. Young normal RBCs have more aggregated PRPPS than do older RBCs. In contrast, due to their decreased ATP and increased DPG concentrations, PK-deficient RBCs contain less aggregated PRPPS than do RBCs of comparable age without PK deficiency. These data suggest that PRPPS should be less active in vivo in PK-deficient RBCs. This may play a key role in mediating the decreases in total adenine nucleotide and total NAD concentrations in these RBCs.     

Extrapulmonary tuberculosis in immunocompetent adults

Tuberculosis continues to be a significant cause of morbidity and mortality. Although tuberculosis usually attacks the lungs, other organs can also be affected, leading to extrapulmonary tuberculosis (EPT) or disseminated tuberculosis. This study retrospectively analysed the incidence, clinical sites and risk factors for EPT in 252 patients with EPT between 1 January 1991 and 30 June 2003. EPT was defined as clinical, laboratory, imaging, and/or histopathological evidence of mycobacterial infection in a site other than hilar lymph nodes or lung parenchyma. In our study group, tuberculous lymphadenitis (36.5%) was found to be the most common clinical presentation of EPT. 119 (47.2%) patients developed the severe form of EPT, according to the WHO report, and 133 (52.8%) patients developed the less severe form. A case history of pulmonary tuberculosis was found to be a risk factor for the development of EPT (p <0.05). The study showed that EPT is still a public health problem. These findings suggested that pulmonary tuberculosis may play a critical role in the development of EPT. 12-month therapy may be chosen in patients with EPT considering acceptable adverse effects without relapses.     

Adhesion of sickle neutrophils and erythrocytes to fibronectin

The pathophysiology of vaso-occlusive crisis in sickle cell disease involves interactions among blood cells, plasma proteins, and vessel wall components. The initial goal of this work was to quantify the adhesion of sickle red blood cells (RBCs) to fibronectin immobilized on glass under both static and dynamic shear stress conditions. High-power microscopic inspection of static assay plates showed striking numbers of adherent neutrophils as well as RBCs. Sickle neutrophils and RBCs were significantly more adherent to fibronectin than the corresponding normal cells in static adhesion assays. Adhesion of both sickle neutrophils and sickle RBCs in dynamic adhesion assays was promoted by a period of static incubation preceding initiation of shear stress conditions. Adherent neutrophils remained attached at shear stresses up to 51 dyne/cm2; most adherent RBCs were attached at shear stresses up to 13 dyne/cm2, but detached at a shear stress of 20 dyne/cm2. Sickle neutrophil adhesion was enhanced significantly by autologous plasma. Elevated levels of plasma interleukin-6 (IL-6; but not IL-1 or IL-8) were found in 6 of 9 sickle cell disease samples examined, and elevated levels of tumor necrosis factor were found in 2 of 9 samples. Plasma IL- 6 levels correlated positively with both the number of sickle neutrophils adherent to fibronectin and the ability of sickle plasma to enhance adhesion of normal neutrophils to fibronectin. These data suggest possible roles for neutrophil activation and for fibronectin in mediating sickle neutrophil and RBC adhesion.     

Effects of Cd^＋2, Cu^＋2, Ba^＋2 and Co^＋2 ions on Entamoeba histolytica cysts

AIM:The effects of cobalt, copper, cadmium and barium ions on the cysts of Entarnoeba histolytica (E.histolytica),an amebic dysentery agent,cultured in Robinson medium were investigated.METHODS: E.histolytica cysts and trophozoites isolated from a patient with amebiasis were cultivated in the medium,incubated at 37℃ for a period of 4 days and 40&#215;10^4/ml amebic cysts were then transferred to a fresh medium. At the second stage, 0.05, 0.1 and 0.2mM of selected metal ions were added to the medium,and the effects of these ions on parasitic reproduction compared with the control group were observed.RESULTS:It was determined that the number of living parasites in all the groups containing metal ions decreased significantly starting from 30 minutes (P&lt;0.01). CuCl2 showed the highest lethal effect on E. histolytica cysts, whereas the lowest lethal effect was observed with CoCl2. It was also seen that the number of living cells was decreased as the ion concentration and exposure time were increased, and that there were no living parasites in the medium at the end of 24h (P&lt;0.01).CONCLUSION:It may be stated that the effect of everincreasing contamination of the environment with metal waste materials on parasites should be investigated further.