Fumihiro Yamasawa

Age-Dependent Changes of Collagen and Elastin Content in Human Aorta and Pulmonary Artery

Collagen and elastin in the arterial wall are thought to show some age-dependent changes, and to relate with development of the arteriosclerotic lesion. Both aortas and the pulmonary trunks were collected from 137 autopsy cases. Biochemical determination of collagen and elastin content was carried out. Collagen and elastin of the aorta and the pulmonary artery showed no significant age-dependent changes. Elastin content of the pulmonary artery increases with age in the adult. This paper seems to be the first report of simultaneous estimation of collagen and elastin content of both the aorta and the pulmonary artery.

Effects of long-term low-dose oxygen supplementation on the epithelial function, collagen metabolism and interstitial fibrogenesis in the guinea pig lung

BackgroundThe patient population receiving long-term oxygen therapy has increased with the rising morbidity of COPD. Although high-dose oxygen induces pulmonary edema and interstitial fibrosis, potential lung injury caused by long-term exposure to low-dose oxygen has not been fully analyzed. This study was designed to clarify the effects of long-term low-dose oxygen inhalation on pulmonary epithelial function, edema formation, collagen metabolism, and alveolar fibrosis.MethodsGuinea pigs (n = 159) were exposed to either 21% or 40% oxygen for a maximum of 16 weeks, and to 90% oxygen for a maximum of 120 hours. Clearance of inhaled technetium-labeled diethylene triamine pentaacetate (Tc-DTPA) and bronchoalveolar lavage fluid-to-serum ratio (BAL/Serum) of albumin (ALB) were used as markers of epithelial permeability. Lung wet-to-dry weight ratio (W/D) was measured to evaluate pulmonary edema, and types I and III collagenolytic activities and hydroxyproline content in the lung were analyzed as indices of collagen metabolism. Pulmonary fibrotic state was evaluated by histological quantification of fibrous tissue area stained with aniline blue.ResultsThe clearance of Tc-DTPA was higher with 2 week exposure to 40% oxygen, while BAL/Serum Alb and W/D did not differ between the 40% and 21% groups. In the 40% oxygen group, type I collagenolytic activities at 2 and 4 weeks and type III collagenolytic activity at 2 weeks were increased. Hydroxyproline and fibrous tissue area were also increased at 2 weeks. No discernible injury was histologically observed in the 40% group, while progressive alveolar damage was observed in the 90% group.ConclusionThese results indicate that epithelial function is damaged, collagen metabolism is affected, and both breakdown of collagen fibrils and fibrogenesis are transiently induced even with low-dose 40% oxygen exposure. However, these changes are successfully compensated even with continuous exposure to low-dose oxygen. We conclude that long-term low-dose oxygen exposure does not significantly induce permanent lung injury in guinea pigs.

Ventilation-perfusion inequality and diffusion impairment in acutely injured lungs

To assess the significant role of diffusion impairment and its unequal distribution in acutely injured lungs with alveolar flooding, oleic acid was intravenously injected into twenty-five mongrel dogs. The animals were divided into two groups, A and B. 0.1% CO in air was delivered, as an inspired gas, to the animals of group A. Simultaneously, saline containing a trace amount of six foreign inert gases was infused through a peripheral vein. While allowing the animals in group B to breathe air, saline containing ethylene, acetylene and freon 22 was infused. After injection of oleic acid, group A revealed increase in intrapulmonary shunt accompanied by a marked broadening of ventilation-perfusion (VA/Q) and diffusing capacity-perfusion (G/Q) distributions. A considerable amount of total cardiac output was received by the lung areas with low G/Q ratios where significant diffusion limitation was predicted to occur. Group B showed that excretion of freon 22 (gas with lower diffusivity) in injured lungs was considerably distorted as compared to those of ethylene and acetylene (gases with higher diffusivities), again ascertaining the importance of diffusion limitation in lungs with exudate in alveolar regions.

Simultaneous continuous 13C, 12C analysis of expired gas in the 13C breath test

The 13C breath test is a method of clarifying the metabolism of loaded substances by administering 13C‐labelled materials and calculating the 13CO2 and 12CO2 ratio (13C/12C isotope ratio) in the expired gas. The materials are metabolized and expelled in the expired gas. Because simultaneous continuous measurement of 13CO2 and 12CO2 in expired gas has been difficult up to the present, respective expired gases, including dead space before and after administration, have been sampled to separate sampling bags and 13C/12C has been measured in the bags and changed fraction of 13C/12C after administration (δ) has been used to judge the metabolic process. This method is affected by the contamination of the dead space gas. In the present study, in order to exclude the dead space effect, simultaneous continuous analysis of 12CO2 and 13CO2 of expired gas identifying alveolar gas was applied to the 13C‐urea breath test in addition to the conventional sampling bag method. Both isotope detectors were attached to a mass spectrometer. Fifty‐six cases receiving stomach health check‐ups for Helicobacter pylori were examined. δ was calculated in the bag or in phase III of continuous gas measurement. Because the bag contains dead space, δ was reduced and sensitivity and specificity with reference to gastric fluoroscopy or Helicobacter pylori IgG antibody were reduced. Decreasing the dead space contamination is important in reducing the measurement error in the 13C breath test and simultaneous continuous measurement is a good tool for this purpose.

Screening of Helicobacter Pylori Infection in the Health Examination Detected by Urea Breath Test and Barium Meal Study

Screening of Helicobacter Pylori Infection in the Health Examination Detected by Urea Breath Test and Barium Meal Study: Fumihiro Yamasawa, et al. Marubeni Clinic

Uneven distribution of ventilation-perfusion ratios in lungs estimated by a modified newton method

AbstractThe uneven distribution of ventilation—perfusion ratios (

Increased expression of inflammatory mediators in small-airway epithelium from tobacco smokers

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Endoscopic Observation of Peripheral Airway Lesions

) in diseased lungs is the major cause of arterial hypoxemia. Farhi and Yokoyama (1967) and Yokoyama and Farhi (1967) were the first who used physiologically inert gases as indicator gases to assess the uneven distribution of