Influence of advanced pulmonary vascular remodeling on accuracy of echocardiographic parameters of left ventricular filling pressure

Evaluation of left ventricular filling pressure plays an important role in the clinical management of pulmonary hypertension. However, the accuracy of echocardiographic parameters for the determination of left ventricular filling pressure in the presence of pulmonary vascular lesions has not been fully addressed. We retrospectively investigated 124 patients with pulmonary hypertension due to pulmonary vascular lesions (noncardiac pulmonary hypertension group) and 113 patients with ischemic heart disease (control group) who underwent right heart catheterization and echocardiography. The noncardiac pulmonary hypertension group was subdivided into less-advanced and advanced groups according to median pulmonary vascular resistance. Pulmonary artery wedge pressure was determined as left ventricular filling pressure. As echocardiographic parameters of left ventricular filling pressure, the ratio of early- (E) to late-diastolic transmitral flow velocity (E/A), ratio of E to early-diastolic mitral annular velocity (E/e′), and left atrial volume index were measured. In the less-advanced noncardiac pulmonary hypertension and control groups, positive correlations were observed between pulmonary artery wedge pressure and late-diastolic transmitral flow velocity (R = 0.41, P = 0.002 and R = 0.71, P < 0.001, respectively) and left atrial volume index (R = 0.53, P < 0.001 and R = 0.41, P < 0.001), whereas in the advanced noncardiac pulmonary hypertension group, pulmonary artery wedge pressure was only correlated with left atrial volume index (R = 0.27, P = 0.032). In the controls, only pulmonary artery wedge pressure determined E (β = 0.48, P < 0.001), whereas both pulmonary artery wedge pressure and pulmonary vascular resistance were independent determinants of E (β = 0.29, P < 0.001 and β = –0.28, P = 0.001, respectively) in the noncardiac pulmonary hypertension group. In conclusion, in the presence of advanced pulmonary vascular lesions, conventional echocardiographic parameters may not accurately reflect left ventricular filling pressure. Elevated pulmonary vascular resistance would lower the E, even when pulmonary artery wedge pressure is elevated, resulting in blunting of echocardiographic parameters for the detection of elevated left ventricular filling pressure.

Ultrafast slow-light tuning beyond the carrier lifetime using photonic crystal waveguides

We demonstrate ultrafast delay tuning of a slow-light pulse with a response time <10 ps. This is achieved using two types of slow light: dispersion-compensated slow light for the signal pulse, and low-dispersion slow light to enhance nonlinear effects of the control pulse. These two types of slow light are generated simultaneously in Si lattice-shifted photonic crystal waveguides, arising from flat and straight photonic bands, respectively. The control pulse blueshifts the signal pulse spectrum, through dynamic tuning caused by the plasma effect of two-photon-absorption-induced carriers. This changes the delay by up to 10 ps only when the two pulses overlap within the waveguide and enables ultrafast tuning that is not limited by the carrier lifetime. Using this, we succeeded in tuning the delay of one target pulse within a pulse train with 12 ps intervals.

Association of susceptibility to the development of pneumonia in the older Japanese population with haem oxygenase-1 gene promoter polymorphism

BACKGROUND

Oxidative stresses including cigarette smoking are implicated in the pathogenesis of cerebrovascular diseases, which are associated with pneumonia because of frequent aspiration. Haem oxygenase-1 (HO-1) acts in cytoprotection against oxidants, provides anti-inflammatory effects, and inhibits atherogenesis. A (GT)(n) dinucleotide repeat in the human HO-1 promoter modulates HO-1 gene expression and shows length polymorphism, which is grouped into three classes: class S (<27 repeats), class M (> or = 27, <33 repeats), and class L (> or = 33 repeats) alleles.

OBJECTIVE

To investigate the correlation between the HO-1 gene polymorphism and development of pneumonia in elderly Japanese.

METHODS

The length of the (GT)n repeats was analysed in 200 elderly patients with pneumonia and 200 control subjects. The association of the HO-1 gene polymorphism with risk of pneumonia was estimated by logistic regression.

RESULTS

The proportion of allele frequencies in class L, and the proportion of genotypic frequencies in the L-allele carriers (L/L, L/M, and L/S), was significantly higher in patients with pneumonia than in controls (20% v 10% in class L, and 34% v 18% in L-allele carriers). After adjustment for potentially confounding factors, both cerebrovascular disorders and HO-1 gene L-allele carriers were significant and independent risk factors for pneumonia. The adjusted odds ratio for L-allele carriers v non-L-allele carrier was 2.1 (95% confidence interval, 1.2 to 3.6).

CONCLUSIONS

The large size of a (GT)n repeat in the HO-1 gene promoter may be associated with susceptibility to pneumonia in the older Japanese population.

Increased circulating endothelial progenitor cells in patients with bacterial pneumonia: evidence that bone marrow derived cells contribute to lung repair

BACKGROUND

Tissue repair often occurs in organs damaged by various inflammatory diseases including pneumonia. Inflammatory stimuli induce a rapid and massive release of inflammatory cells from the bone marrow. Recent studies have suggested that bone marrow cells have the potential to differentiate into a variety of cell types. It has been shown that administration of lipopolysaccharide (LPS) to murine lungs induces a rapid release of endothelial progenitor cells (EPCs) into the circulation, and that bone marrow derived progenitor cells including EPCs contribute to lung repair after lung injury in mice. This study was undertaken to investigate the mobilisation of EPCs in humans following acute pneumonia.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood taken from 23 patients with pneumonia during both the acute and convalescent phase. 1x10(6) PBMCs were plated on fibronectin coated culture slides and cultured in culture medium for endothelium. The numbers of EPCs were counted 8 days after plating.

RESULTS

The number of circulating EPCs significantly increased in patients with pneumonia (p<0.0001). Patients with low EPC counts tended to have persistent fibrotic changes in their lungs even after their recovery from pneumonia.

CONCLUSIONS

Inflammatory stimuli induce a rapid release of EPCs into the circulation in humans. A sufficient number of EPCs is necessary for proper lung repair following bacterial pneumonia.

[Prediction of progression in patients with mild cognitive impairment using IMP-SPECT]

To examine the difference in functional brain imaging between mild cognitive impairment (MCI) and normal aging, we measured rCBF on functional brain imaging using 123I-IMP single photon emission computed tomography (IMP-SPECT) in 19 MCI patients who progressed to develop AD on follow-up and 23 probable Alzheimer's disease (AD) patients as well as 15 age-matched normal subjects. Baseline MMSE score was 25.3 (SD 1.2) in the MCI group and 17.5 (SD 3.3) in the AD group. The regions of interest (ROI) in the posterior cingulate gyrus, frontal, temporal and parietal cortices were drawn on the image of IMP-SPECT with reference to an individual MRI image. The rCBF ratio was calculated using ROI value in the cerebellum as a reference. Voxel-based analysis was also preformed using statistical parametric mapping (SPM). The rCBF ratio in the posterior cingulate gyrus was significantly reduced in the MCI group (mean 0.956, SD 0.080) and the AD group (mean 0.833, SD 0.118) compared to that in the normal group (mean 1.083, SD 0.084). In the frontal, temporal and parietal cortices, the rCBF ratio was significantly reduced only in the AD group compared to the normal group. At a fixed specificity of 80%, the diagnostic sensitivity in the discrimination between MCI patients and normal subjects was 80.5% when using rCBF ratio in posterior cingulate gyrus. In the SPM analysis, significant reduction of the rCBF in MCI group was observed only in the posterior cingulate gyrus, compared with normal subject group. Our results suggest that MCI patients presenting with a posterior cingulate hypoperfusion are at higher risk for transition from MCI to clinically recognizable AD.

18F-fluorodopa PET study of striatal dopamine uptake in the diagnosis of dementia with Lewy bodies

Using (18)F-fluorodopa PET and a constant 0.0062 influx rate in the putamen, dementia with Lewy bodies (n = 7) was distinguished from AD (n = 10) with a sensitivity of 86% and a specificity of 100%. A constant 0.0071 influx rate in the caudate yielded a sensitivity of 71% and a specificity of 100% for distinction of the two disorders. Despite a limited sample size, these findings suggest that assessing nigrostriatal dopaminergic function with (18)F-fluorodopa PET may be a useful diagnostic aid in cases of dementia with Lewy bodies while patients are alive.