Blood flow and oxygen consumption with near-infrared spectroscopy and venous occlusion: spatial maps and the effect of time and pressure of inflation

We have measured the local blood flow (BF) and oxygen consumption (OC) in the human calf muscle using near-infrared spectroscopy during venous occlusion. Venous occlusion was achieved by inflating a pneumatic cuff around the thigh of the subject. We have investigated the influence of the inflation time and cuff pressure on the recovered values of BF and OC. We have found that if the cuff pressure is increased from a threshold pressure (approximately 30 mm Hg) to a critical pressure (approximately 45 mm Hg) in less than about 6 s, one measures the same values of BF and OC independent of the total inflation time and final cuff pressure. We also report nine-pixel spatial maps of BF and OC to show that this technique can lead to spatially resolved measurements of blood flow and oxygen consumption in tissues.     

Comparison of optic nerve head measurements obtained by optical coherence tomography and confocal scanning laser ophthalmoscopy

PURPOSE: To evaluate the relationship between optic nerve head (ONH) measurements generated by optical coherence tomography (OCT; versions 2 and 3) and confocal scanning laser ophthalmoscopy (CSLO) and to compare the association between OCT and CSLO ONH measurements with glaucoma disease status, as determined by clinical evaluation and perimetry. DESIGN: Cross-sectional study. METHODS: In a prospective study in the glaucoma service of an academic department of ophthalmology, 159 eyes (97 subjects) and 77 eyes (44 subjects) were recruited in two separate periods. All subjects were scanned with a CSLO device. Subjects tested within the first period of recruitment were scanned with OCT version 2 and in the second period with OCT version 3. The main outcome measure was the correlation between automatic and manually defined OCT ONH measurements and the correlation of CSLO and OCT ONH measurements between devices and with glaucoma disease status. RESULTS: A high correlation was found between ONH measurements obtained by the automatic determination of ONH margin and those obtained by manual tracing of the disk margin (r =.93 to.98). Optical coherence tomography and CSLO ONH measurements were highly correlated. Optical coherence tomography-measured mean disk area was significantly larger than that measured by CSLO, as were all other disk size-related parameters. The areas under the receiver operator characteristic (AROC) curves for the associations between CSLO and OCT ONH measurements and clinical diagnosis were found to be similar and in the range of 0.47 to 0.79 for both devices. CONCLUSIONS: Automated OCT ONH measurements correlate highly with those obtained by manual tracing of disk margin. Optical coherence tomography and CSLO ONH analyses are highly correlated and have similar associations with glaucoma disease status.     

青光眼视网膜神经纤维层厚度的光学相干断层扫描纵向评估

目的：纵向评估光学相干断层扫描（OCT）视盘周围神经纤维层厚度测量，并将这些检查与临床状态和自动视野计检查作横向比较。 方法：对参与前瞻性纵向研究的青光眼或疑似青光眼患者64只眼（37例）作回顾性评估。所有参与者每6个月作一次全面的临床评估、视野检查和OCT。视野进展按可重复性测量的视野平均偏差至少比基线降低2dB，OCT进展按可重复性测量视网膜神经纤维层平均厚度至少变薄20pro。 结果：每个患者在中位值为4．7年的随访中有5个可使用的OCT扫描。青光眼和疑似青光眼患者之间视网膜神经纤维层厚度线性回归斜度的差异对所有变量均不显著；然而，Kaplan-Meier生存曲线分析显示视野比OCT测量有较高的进展率。在随访期间66％的眼是稳定的。22％只有OCT进展，9％单有视野平均偏差进展。3％视野和OCT都有进展。 结论：OCT比全自动视野计对辨别青光眼进展有更大的可能性。这可能反映OCT的敏感性或在常规方法发现之前其真实损害就能被OCT发现。     

Artificial device for extracorporeal blood oxygenation in rats

Abstract:  Blood oxygenation devices are an essential component of any cardiopulomonary bypass circuit in various species of laboratory animals. When using larger animals like dogs or pigs, the human and pediatric blood oxygenators could be easily used, but the disadvantage of these species is the scarcity of biochemical and genetic assays for experimental follow-up. However, small rodents like rats have plenty of biochemical assays, but their size requires special oxygenators adapted for their small blood volume and often primed with blood of another animal or other physiological solution. We showed the new design of a blood oxygenator with direct blood–gas contact in an open circuit, specially designed for rats in which the blood oxygenation takes place in a slowly rotating plastic tube with blood spread onto its inner walls in a thin layer. The oxygenator is simple and efficient, does not require priming with the blood of another rat, has a small dead volume, is reusable, and easy to clean and sterilize.     

Deletion of hensin/DMBT1 blocks conversion of beta- to alpha-intercalated cells and induces distal renal tubular acidosis

Acid-base transport in the renal collecting tubule is mediated by two canonical cell types: the β-intercalated cell secretes HCO(3) by an apical Cl:HCO(3) named pendrin and a basolateral vacuolar (V)-ATPase. Acid secretion is mediated by the α-intercalated cell, which has an apical V-ATPase and a basolateral Cl:HCO(3) exchanger (kAE1). We previously suggested that the β-cell converts to the α-cell in response to acid feeding, a process that depended on the secretion and deposition of an extracellular matrix protein termed hensin (DMBT1). Here, we show that deletion of hensin from intercalated cells results in the absence of typical α-intercalated cells and the consequent development of complete distal renal tubular acidosis (dRTA). Essentially all of the intercalated cells in the cortex of the mutant mice are canonical β-type cells, with apical pendrin and basolateral or diffuse/bipolar V-ATPase. In the medulla, however, a previously undescribed cell type has been uncovered, which resembles the cortical β-intercalated cell in ultrastructure, but does not express pendrin. Polymerization and deposition of hensin (in response to acidosis) requires the activation of β1 integrin, and deletion of this gene from the intercalated cell caused a phenotype that was identical to the deletion of hensin itself, supporting its critical role in hensin function. Because previous studies suggested that the conversion of β- to α-intercalated cells is a manifestation of terminal differentiation, the present results demonstrate that this differentiation proceeds from HCO(3) secreting to acid secreting phenotypes, a process that requires deposition of hensin in the ECM.     

Accumulation of tissue macrophages and depletion of resident macrophages in the diabetic thymus in response to hyperglycemia-induced thymocyte apoptosis

AimsWe investigated the dynamics and morphology of thymus macrophages in response to thymus involution caused by hyperglycemia. Thymus is an organ affected early and dramatically after the onset of diabetes, losing most of the thymocyte populations but diabetes's impact on the components of the thymus stroma is largely unknown.MethodsRats were injected with streptozotocin and thymus weight, body weight, and glycemia were measured at various time points. The dynamics and morphology of macrophages in the diabetic thymus were investigated by histology, immunohistochemistry, qPCR, electron microscopy and flow cytometry.ResultsIn hyperglycemic animals the involuting thymus is gradually infiltrated by tissue macrophages (ED1-positive) and depleted of resident macrophages (ED2-positive). While ED1 positive macrophages are scattered in both cortex and medulla the ED2 positive ones are limited to the cortex and cortico-medullary junction. CD4 + CD11b + macrophages also accumulate. The TUNEL reaction that detects the degradation of the DNA from apoptotic thymocytes in the macrophages is enhanced. The thymic macrophages enlarge and accumulate lipid vacuoles and apoptotic bodies. qPCR measurements of the expression of macrophage markers showed a persistent increase in the diabetic thymus after the injection of streptozotocin.ConclusionsThymus involutes rapidly and persistently after the onset of hyperglycemia because of the elevated apoptosis in the thymocytes. Tissue macrophages accumulate in the thymus and the resident macrophages decrease. This results in an overall increase in macrophage activity in the diabetic thymus in response to the elevated apoptosis of thymocytes produced by hyperglycemia.