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Biomedical subjects

T Kagawa

Publications and source records attributed to T Kagawa.

At least 145 records · Page 8Linked to original sources
PubMed1984

Surgical treatment of pulmonary abscess in children under ten years of age.

Ten children under ten years of age with pulmonary abscess were treated surgically between 1962 and 1982. In nine patients, lobectomies with or without pulmonary decortication were performed; and in one case, drainage via a chest tube directly from the abscess cavity was successful. There were no surgical or late postoperative deaths. All patients recovered without any complication. The postoperative course has been followed for two months to 20 years. The effect of treatment is correlated with the clinical type of abscess.

Child↗
PubMed1984

Secondary CO2 diffusion following HCO3- shift across the red blood cell membrane.

In order to clarify the interaction between CO2 diffusion and HCO3- shift in the red blood cell (RBC), HCO3- shift was measured by using a stopped flow method combined with fluorometry. When HCO3- entered the RBC, the intracellular PCO2 increased, causing a secondary outflow of CO2. Conversely, when HCO3- ions flowed out of the RBC, the resulting decrease of PCO2 caused an inward CO2 diffusion. The PCO2 change caused by the inward HCO3- shift was about 3- to 4-fold that of the outward shift. During the respective in- and outward-shifts, the mean half-times of the extracellular pH changes were 0.15 and 0.13 sec. These were approximately twice as long as those of the primary CO2 diffusion. The permeability of HCO3- across the RBC membrane was obtained by comparing the experimental extracellular pH curve with a numerical solution for CO2 and HCO3- diffusions accompanied by the hydration and dehydration reactions. Thus the HCO3- permeability was determined to be 5 x 10-4 cm/sec, in the in- and outward-HCO3- shifts, respectively. The influence of Cl- concentration on HCO3- permeability was tested by reducing the initial Cl- gradient across the RBC membrane. In a physiological Cl- concentration range the HCO3- permeability was not affected by the Cl- gradient.

Bicarbonates↗
PubMed1984

Numerical solution of partial differential equations for CO2 diffusion accompanying HCO3- shift in red blood cells.

A computer program for a numerical solution of the CO2 diffusion in the red blood cell including the HCO3- shift was developed. Comparing the calculated extracellular PCO2 curve with the experimental data on the primary and secondary CO2 diffusions, the permeabilities of CO2 and HCO3- across the red cell membrane, eta(CO2) and eta(HCO3-), were determined as eta(CO2)= 2.5 x 10(-6) cm/(sec.Torr), Inward eta(HCO3-), = 5 x 10(-4) cm/sec, Outward eta(HCO3-) = 7 x 10(-4) cm/sec. The dependencies of the CO2 diffusion rate on the hematocrit and initial intra- and extracellular HCO3- concentrations were examined using the above permeabilities. The half-time of the extracellular PCO2 change in a closed RBC suspension was obviously reduced as the hematocrit and initial extracellular HCO3- increased, while the effect of the initial intracellular HCO3- was not significant. The CO2 diffusion in vivo was simulated using pulmonary and tissue capillary models. The half-time of the extracellular HCO3- change was about 0.15 sec, while that of the intracellular HCO3- change ranged from 40 to 60 msec.

Bicarbonates↗
PubMed1984

[Three surgically treated cases of spontaneous rupture of the esophagus with reference to a new surgical approach--eversion stripping and esophagogastrostomy through the posterior mediastinum].

Three surgical cases of spontaneous rupture of the esophagus were reported. Case 1 was a 56-year-old man who was admitted 3 days after the onset was treated with open drainage. He had no complications whatsoever 8 years after the treatment. In case 2 (a 55-year-old man), eversion stripping of the esophagus and gastrostomy were performed 2 months after diagnosis, but esophageal reconstruction was not successful. He died of acute congestive heart failure 5 years after surgery. The Third case was a 60-year-old women whose rupture was confirmed 11 days after the onset. Cervical esophagostomy, gastrostomy and jejunostomy were performed 16 days after the rupture. Thereafter, esophageal eversion stripping and esophagogastrostomy through the posterior mediastinum were successfully carried out 2 months after the first surgery. She had no postoperative complications. Eversion stripping of the esophagus with esophagogastrostomy through the posterior mediastinum is an effective and safe method for some advanced cases of spontaneous esophageal rupture. We have not found any reports of surgical cases with spontaneous esophageal rupture treated by this approach in the literature.

Esophageal Diseases↗
PubMed1983

Derivation of theoretical equations of the CO2 dissociation curve and the carbamate fraction in the Haldane effect.

The simultaneous Henderson-Hasselbalch equations in plasma and red cell were solved in order to obtain the CO2 dissociation curve of oxygenated blood. In order to solve the above two equations the following equation was added, in which the relationship between the intracellular (delta pHC) and the extracellular pH change (delta pHP) was defined as follows: pHC = (1 + sigma) delta pHP, where 1 + sigma is a factor to be determined from experimental data on Donnan's ratio for H+. From the solution, the ratio of bicarbonate shift to the CO2 quantity released out of or combined with hemoglobin was calculated. The solution was validated by comparing the above ratio between the theoretical and experimental data. The CO2 contents calculated at 12 Torr in whole blood, red cell, and plasma compartments show good agreement with the respective analyzed values. When the buffer values of hemoglobin and plasma buffer protein were 70.0 and 7.5 mmol/(liter plasma X pH), respectively, sigma = -0.21 + 0.05 X delta pHP, and the Donnan's ratio for HCO3- was assumed to be 0.7 at pH = 7.33, the theoretical CO2 dissociation curve fitted well with the experimental curve. The CO2 dissociation curve of deoxygenated blood was expressed by adding the measured Haldane effect to the CO2 content of oxygenated blood. This additive characteristic in turn made it possible to estimate carbamate contribution in the Haldane effect.

Carbamates↗
PubMed1983

Quantitative analyses of the CO2 dissociation curve of oxygenated blood and the Haldane effect in human blood.

The theoretical equations for the CO2 dissociation curve derived by MOCHIZUKI et al. (1983) have made it possible to estimate the CO2 contents in blood at any PCO2 by putting the intra- and extracellular bicarbonate contents at a certain PCO2 into them. Moreover, according to their Haldane effect equation, the carbamate and bicarbonate contributions are evaluated, when the Haldane effect and its plasma component are known along the PCO2 range. In order to accomplish the above calculation the water shifts due to the PCO2 and O2 saturation changes were measured as the changes of hematocrit. The hematocrit of oxygenated blood was linearly correlated to pH with a factor of -0.037, and the difference in hematocrit between oxygenated and deoxygenated bloods was 0.004 in terms of fractional hematocrit. The blood and plasma CO2 contents measured at four different PCO2's were compared with the ones calculated by use of the intra- and extracellular bicarbonate contents at 42 Torr PCO2. The measured and calculated CO2 contents coincided fairly well with each other. Using intra- and extracellular bicarbonate contents in oxygenated blood together with the Haldane effect and its plasma component, the carbamate contribution was then calculated. The carbamate content was about 1.2 mmol/liter blood over a PCO2 range of 20 to 100 Torr, and its ratio to the total Haldane effect decreased from 50 to 40%, as PCO2 was increased. The ratio of the bicarbonate shift to the total bicarbonate change due to the Haldane effect, ranging from 0.82 to 0.66, was significantly greater than that measured by changing PCO2.

Carbamates↗
PubMed1983

5-Fluorouracil derivatives. III. A simple method to prepare 5-fluoro-2'-deoxyuridine derivatives.

3',5'-Diacyl-2'-bromo-5-fluoro-2'-deoxyuridine (4) was obtained by the reaction of 5, 6-dihydro-6-hydroxy-5-fluorouridine (2) and acyl bromide. Because the route from uridine (1) to 2, the route from 4 to 3',5'-diacyl-5-fluoro-2'-deoxyuridine (5), and the route from 5 to 5-fluoro-2'-deoxyuridine (FUDR, 6) are known reactions, the three step synthesis from uridine to 5 and four step synthesis from uridine to FUDR have been accomplished.

Chemical Phenomena↗