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Biomedical subjects

M Yagi

Publications and source records attributed to M Yagi.

At least 199 records · Page 11Linked to original sources
PubMed1989

A method for determining reference points in celloidin specimens for computer graphic reconstruction.

For three-dimensional computer graphic reconstruction of histological sections, it is important to determine reference points. We have developed a machine that makes reference points in a celloidin block for this purpose by drilling holes straight into the block. A sliding microtome is placed under the machine, which consists of a worktable, a stand, and a motor-driven unit. The celloidin block is sectioned on a microtome to determine a plane for serial sectioning. Several holes are then drilled in the block vertical to the plane selected. Serially sectioned specimens are next stained with hematoxylin and eosin and are mounted in the usual manner. Three-dimensional reconstructions of the specimens were next done using a PC-9801 computer and CosmoZone-S software. As an example, the reconstruction of a guinea pig stapes is described.

Animals↗
PubMed1989

Utilization for protein synthesis in individual rat organs of extracellular 2-ketoisocaproate relative to utilization of extracellular leucine.

Rats were given constant intravenous infusions of [3H]-leucine plus [1-14C]-2-ketoisocaproate (KIC). Specific activities of plasma leucine and plasma KIC reached plateaus by two to three hours. 3H specific activity of KIC was 85% +/- 2% of that in leucine. 14C specific activity of leucine was 36% +/- 2% of that in KIC. The 14C/3H ratios in leucine and KIC were constant from the earliest sampling time (one hour) at 0.65 +/- 0.03 and 2.20 +/- 0.07, respectively. In various tissues, 14C/3H in free leucine and in tissue protein were approximately equal, but in most organs these ratios were significantly greater than the ratio 14C/3H in plasma leucine. From these data we estimate that the fraction of leucine incorporated into protein in individual organs derived from extracellular KIC rather than extracellular leucine varies from zero (in liver and bone marrow) to 35% to 45% (in brain and heart), and comprises 12% in the body as a whole.

Animals↗
PubMed1989

Studies on intestinal motility and mechanism of cholangitis after biliary reconstruction.

Cholangitis is a serious complication of biliary reconstruction for congenital biliary atresia. To observe the effect of intestinal motility on the mechanism of cholangitis, we studied intestinal motility in dogs after experimental common duct ligation and reconstruction by Roux-en-Y or interposition cholecystojejunostomy. One year after operation, bipolar electrodes were implanted in the canine intestine and electromyograms were performed. Distinct patterns of propagation and the direction of intestinal motility characteristic of each procedure were observed. The animals with Roux-en-Y loops showed a decrease in motility of the duodenum and upper jejunum. Those with an interposed segment demonstrated stagnation in both the duodenum and jejunum, and poor coordination of intestinal movement. The myoelectric activity of the Roux-en-Y loop suggests that it is the reconstruction technique most likely to prevent reflux cholangitis.

Anastomosis, Roux-en-Y↗
PubMed1989

Perioperative change of plasma endotoxin levels in early infants.

As a preliminary study to elucidate the relationship of endotoxemia to postoperative morbidity, the plasma endotoxin levels in 64 surgical neonates were quantitated by the chromogenic limulus test (Toxicolor test; Seikagaku Kogyo, Tokyo, Japan). The preoperative levels of plasma endotoxin were 64 +/- 59 pg/mL in the group of infants with perforated peritonitis (n = 9), 63 +/- 51 pg/mL in the group of infants with gastroschisis (n = 7), and 15 +/- 16 pg/mL in the group of infants with ileus (n = 28), while the mean level was 6 +/- 5 pg/mL in the remaining 20 surgical neonates who had no signs of ileus or peritonitis. In the serial determination of plasma endotoxin in 28 neonates, the levels on the first postoperative day increased significantly compared with the preoperative levels (16 +/- 18 pg/mL to 46 +/- 25 pg/mL, P less than .01). They decreased gradually to 8 +/- 5 pg/mL within a week in 15 neonates who had no postoperative complications. However, in 13 neonates who had postoperative complications such as wound infection or postoperative ileus, the postoperative levels of plasma endotoxin increased to a much higher level and remained there. In this article the relationship of clinical endotoxemia to postoperative thrombocytopenia and hyperbilirubinemia is analyzed, and the usefulness of evaluating endotoxemia in surgical neonates is discussed.

Bacterial Infections↗
PubMed1989

Comparison of recorded values from six pulse oximeters.

Recorded values (SpO2) of oxygen saturation from six noninvasive pulse oximeters were compared to each other and to the value from a cooximeter. Simultaneous measurements were obtained from each instrument in eight healthy nonsmoking volunteers rendered hypoxic greater than 70% SpO2. Functional arterial oxygen saturation (SaO2), fractional SaO2 (%HbO2), and percent fraction of carboxyhemoglobin (HbCO) and methemoglobin (MetHb) were determined by a cooximeter. The difference between SaO2 and %HbO2 was 2.3 +/- 0.3 (SD) % (p less than .001) with 1.4 +/- 0.1% HbCO and 0.9 +/- 0.1% MetHb. The SpO2 values in two instruments were close to %HbO2, while the other instruments correlated approximately with SaO2. The greatest SpO2 difference among the instruments was 2.7 +/- 1.9% (p less than .001). These results may indicate that, under normal dyshemoglobin levels, some pulse oximeters are calibrated to estimate SaO2 and others to estimate %HbO2. Since the pulse oximeter using two wavelengths cannot measure accurately %HbO2 or SaO2 in the presence of dyshemoglobin, SpO2 values would be independent from %HbO2 and SaO2. A standard calibration method for pulse oximeters should be established by the manufacturers.

Adult↗
PubMed1989

WS-9659 A and B, novel testosterone 5 alpha-reductase inhibitors isolated from a Streptomyces. I. Taxonomy, fermentation, isolation, physico-chemical characteristics.

WS-9659 A and B, produced by Streptomyces sp. No. 9659, were extracted from cultured broth, purified by solvent extraction followed by chromatography on silica gel and then isolated as prisms (C22H24N2O, mp 161 approximately 162 degrees C, C22H23N2OCl, mp 152 approximately 153 degrees C). WS-9659 A and B have testosterone 5 alpha-reductase inhibitory activity. The IC50 values of WS-9659 A and B for partially purified rat prostate testosterone 5 alpha-reductase were 5.0 x 10(-7) M and 1.0 x 10(-5) M, respectively.

5-alpha Reductase Inhibitors↗
PubMed1989

WS-9659 A and B, novel testosterone 5 alpha-reductase inhibitors isolated from a Streptomyces. III. Biological characteristics and pharmacological characteristics.

WS-9659 A, a novel phenazine, produced by a Streptomyces sp., had testosterone 5 alpha-reductase inhibition activity on rat, dog and human prostates. However, WS-9659 A did not show any inhibitory activities for aldose reductase on rabbit lenses and lactate dehydrogenase on pig hearts. WS-9659 A was a competitive inhibitor against testosterone 5 alpha-reductase on rat prostates by use of testosterone as a substrate. Radio receptor binding assay of androgen receptor of rat prostates revealed that WS-9659 A had no affinity for this receptor. WS-9659 A was tested subcutaneously in immature castrated rats to confirm its effect on the growth of the ventral prostates induced by testosterone propionate.

5-alpha Reductase Inhibitors↗
PubMed1989

Stability of CAT gene transcript depends on the 3'-end structure.

To determine the involvement of 3'-end structure of mRNA in the regulation of gene expression in eukaryotic cell, a series of pSCAT plasmids was constructed with chloramphenicol acetyltransferase (CAT) gene and the 3'-regulatory elements from various eukaryotic genes. As a result of determination of the CAT activities and the mRNA level generated from these plasmids, both results were well correlated. Furthermore, the treatment of transfected cells with phorbol ester (TPA) revealed that the polyadenylated CAT mRNAs form some genes were stabilized, in contrast, the mRNAs bearing 3'-end structure of histone or C-myc genes were not.

Chloramphenicol O-Acetyltransferase↗
PubMed1989

[Changes in the electroretinogram during enflurane anesthesia].

We have investigated a method of intraoperative monitoring of anesthetic depth using the electroretinogram (ERG). The effects of enflurane on ERG were studied in 12 patients undergoing surgical procedures. Recordings were made at 0%, 0.8%, 1.7% end-tidal enflurane concentrations. There were statistically significant increases in the latencies of the a-waves, b-waves and oscillatory potentials (OP) with increasing concentrations of enflurane. The amplitudes of the a-waves were reduced with increasing concentrations of enflurane, but the amplitudes of the b-waves did not change. The latencies of OP were thought to be the most sensitive indicator of the anesthetic depth among these parameters. To apply this technique to clinical practice, there were many problems to be solved. However, this may be one of useful monitors of anesthetic depth in future.

Adult↗
PubMed1989

[Is massive fluid load indispensable for the parturient immediately before regional anesthesia?].

One hundred healthy parturients scheduled for elective cesarean section were studied prospectively. Fifty patients received spinal anesthesia with 12mg of hyperbaric tetracaine and were defined as the spinal group. Other fifty patients received epidural anesthesia with 300mg of lidocaine and were defined as the epidural group. A half of patients in each group were given 1,000ml of Ringer's lactate immediately before the regional anesthesia (prehydrated). Rapid hydration was not given to another half of them (non-prehydrated). In the spinal group, ephedrine administration was needed significantly less frequently for prehydrated patients than for non-prehydrated ones. And the mean dose of this drug for prehydrated patients was significantly less than that for non-prehydrated ones. In the epidural group, though prehydration tended to prevent maternal hypotension, neither rate of ephedrine administration nor mean doses of this drug showed any significant difference between prehydrated and non-prehydrated patients. Prehydration did not improve significantly neither acid-base balances of umbilical arterial and venous blood nor Apgar scores of the neonates in either group. We conclude that massive fluid load is not indispensable immediately before the regional anesthesia for the parturient. Furthermore, because this method is not reliable, its advantages and disadvantages including the possibility of enhancing pulmonary edema should be evaluated.

Adult↗
PubMed1989

[Analgesia and anesthesia induced by subanesthetic concentrations of nitrous oxide].

This study was aimed to determine 1) the changes of the anesthetic and analgesic actions of inhalation of subanesthetic concentration of nitrous oxide, and 2) the possible antagonism by naloxone of these actions. Auditory response time (anesthetic action) and pain threshold (analgesic action) were examined before, during and after inhalation of subanesthetic concentration of nitrous oxide in six normal volunteers who were treated with or without intravenous administration of naloxone 1.4 mg. Analgesic action remained at 30 min after nitrous oxide inhalation, while auditory response time returned to control values. Both anesthetic and analgesic effects were unchanged during 100 min inhalation or administration of naloxone. These results indicate that the acute tolerance to these actions of nitrous oxide will not occur, and that naloxone will not show a significant antagonistic action as is observed with morphine.

Administration, Inhalation↗
PubMed1988

A case report of intrahepatic biliary atresia showing an unusual liver histology.

The extrahepatic biliary tract of a male infant, including both the left and right hepatic ducts, was proven to be patent up until his time of death, however, histologic examination of the liver revealed severe fibrosis of the portal areas with ductular proliferation, scattered bile thrombi, and subsequent biliary cirrhosis. In this case, since the obstructive lesion occurred at the secondary branching of the bilateral hepatic duct and because fewer changes were present in the interlobular bile ducts, it seemed possible to consider that the liver histology revealed findings similar to those of extrahepatic biliary atresia.

Bile Ducts, Intrahepatic↗