Effectiveness of 16S ribosomal DNA real-time PCR and sequencing for diagnosing bacterial keratitis

Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate the efficacy of real-time PCR for 16S ribosomal DNA (16S r-DNA) and sequencing for diagnosing microbial keratitis. We...     

Impact of turbulent blood flow in the aortic root on de novo aortic insufficiency during continuous-flow left ventricular-assist device support

Severe aortic insufficiency (AI) after implantation of continuous-flow left ventricular-assist device (LVAD) affects device performance and outcomes. However, the mechanism for the occurrence and progression of AI has not been elucidated. We investigated the impact of nonphysiological retrograde blood flow in the aortic root on AI after LVAD implantation. Blood flow pattern was analyzed in patients with and without AI (n = 3 each) who underwent LVAD implantation, by computational fluid dynamics with patient-specific geometries, which were reproduced using electrocardiogram-gated 320-slice computed tomographic images. The total volume of retrograde blood flow during one cardiac cycle (716 ± 88 mL) was higher and the volume of slow blood flow (<0.1 cm/s) (0.16 ± 0.04 cm³) was lower in patients with AI than in those without AI (360 ± 111 mL, P = .0495, and 0.49 ± 0.08 cm³, P = .0495, respectively). No significant difference in wall shear stress on the aortic valve was observed between the groups. Patients with AI had a perpendicular anastomosis at the distal ascending aorta and the simulation in the modified anastomosis model of patients with AI showed that the retrograde blood flow pattern depended on the angle and position of anastomosis. Computational fluid dynamics revealed strong retrograde blood flow in the ascending aorta and aortic root in patients with AI after LVAD implantation. The angle and position of LVAD outflow anastomosis might impact retrograde blood flow and de novo AI after LVAD implantation.     

Regulation of Macrophage-Mediated Xenocytotoxicity by Overexpression of Alpha-2,6-sialyltransferase in Swine Endothelial Cells

Macrophages play an important role in xenogenic rejection and therefore may represent a major obstacle in clinical application of xenograft. CD33-related sialic acid–binding immunoglobulin–like lectins (Siglecs) belong to the immunoglobulin superfamily and contain a cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM) that is able to inhibit cytokine production. Because human macrophages express various CD33-related Siglecs, we hypothesized that overexpression of α-2,6-sialyltransferase (2,6-ST) in swine endothelial cells (SECs) might prevent the cytotoxicity mediated by macrophages. To confirm our hypothesis, the cytotoxicity of macrophages against 2,6-ST–overexpressing SECs was determined with the use of in vitro–generated macrophages as an effector and naïve or 2,6-ST–overexpressing SECs as a target. The 2,6-ST–overexpressing SECs were established by transfection with the genes for 2,6-ST. Transfection of 2,6-ST led to significant reduction in cytotoxicity compared with naïve SECs. These findings indicate that the sialylated ligands against CD33-related Siglecs may provide an effective therapeutic strategy to inhibit macrophage-mediated xenograft rejection in xenotransplantation.     

Transthyretin (prealbumin) in the pancreas and sera of newly diagnosed type I (insulin-dependent) diabetic patients.

We investigated transthyretin (TTR) in the pancreases and sera of 10 newly diagnosed type I diabetic patients by immunohistochemistry and nephelometry. In the type I diabetic pancreases, glucagon-positive A-cells showed strong immunoreactivity for TTR, the intensity and distribution pattern of which corresponded to those in normal subjects. Morphometric analysis revealed that the amount of strongly TTR-positive A-cells was not significantly different from that in normal subjects. On the contrary, insulin-positive B-cells, which normally show uneven and weak TTR immunoreactivity, decreased in number, and only a few residual B-cells showed faint immunoreactivity. Neither somatostatin cells nor pancreatic polypeptide cells were positive for TTR. The serum TTR concentration showed a significant decrease in type I diabetic patients compared with that in normal subjects (P less than 0.005). These data suggest that the synthesis or storage of TTR in A-cells is not affected, but that in B-cells is impaired in type I diabetes. The decrease in serum TTR might be one of the features of metabolic disorders in type I diabetes.     

Gender differences in the incidence and progression of diabetic retinopathy among Japanese patients with type 2 diabetes mellitus: A clinic-based retrospective longitudinal study

A clinic-based retrospective longitudinal study conducted for 5.8 ± 2.5 years, including 383 (M/F 245/138) Japanese patients with type 2 diabetes mellitus showed that females exhibit a significantly higher prevalence of proliferative diabetic retinopathy (DR) at baseline and that female gender is an independent risk factor for the development of DR.