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Biomedical subjects

Y Takehara

Publications and source records attributed to Y Takehara.

At least 109 records · Page 6Linked to original sources
PubMed1989

Scintigraphic evaluation of brain death with 99mTc-d,l-hexamethyl-propyleneamine oxime (HMPAO).

Lately, the criteria of brain death is being discussed. Cerebral scintigram, especially scintigraphic evaluation of brain death by dynamic study, has been previously reported. Cerebral imaging using radiolabeled amines such as 123I-IMP N-isopropyl-p-iodoamphetamin (IMP) or 99mTc d,l-hexamethyl-propyleneamine oxime (HMPAO) offers a significant information of brain death by the finding of "non visualized brain". However, the dynamic scintigram acquired during the bolus injection of 99mTc-HMPAO provides an additional information of brain death by classical "hot nose sign". 99mTc-HMPAO is able to be administered relatively in a large amount of dose. This cerebral perfusion tracer is lipophilic and remains in the central nervous system, which characterize its role as an reliable indicator of cerebral blood flow. As a result, this compound became suitable for the non-invasive study of brain circulation when the diagnosis of brain death is uncertain. We report a case of brain death in which diagnosis was made by the classical "hot nose sign" in dynamic scintigraphy performed when 99Tc-HMPAO was injected as well as the SPECT which showed a lack of cerebral visualization at the equilibrium state. As far as we are informed, this additional procedure used in the diagnosis of brain death has not reported before. The importance of performing a dynamic scintigram at the administration of 99mTc-HMPAO is also discussed in this report.

Aged↗
PubMed1989

Changes in release of N-acetyl-beta-D-glucosaminidase, gamma-glutamyl transpeptidase and leucine aminopeptidase from renal tubular cells under anaerobic conditions.

Although the urinary excretion of NAG and gamma-GTP has been employed as an index of renal injury, the mechanism of release of these enzymes remains unclear. In the case of renal ischemic injury, we recently reported that u-NAG and u-gamma-GTP were not correlated well with the degree of renal damage especially in the late phase of ischemic injury [1]. In order to elucidate the relationship between release of these enzymes and renal ischemic injury, we devised an in vitro model of anoxic injuries to renal tubular cells and measured the time-course release of NAG (a lysosomal enzyme), gamma-GTP and LAP (brush border enzymes) at 37 degrees C under five different aerobic and anaerobic conditions (95% O2, 20% O2, 10% O2, 3% O2 and 0% O2). The ATP and lactate levels in the system were also measured to estimate the metabolic state of the tubular cells. In the 3% O2, 10% O2 and 20% O2 groups, NAG, gamma-GTP and LAP were released into the media at a similar rate to that in the 95% O2 group, and anaerobic damage to the renal tubular cells was not observed. In the 0% O2 group, the NAG in the medium increased from 60 to 180 min at a significantly higher rate than that of the 95% O2 group, and a linear relationship was observed between NAG concentration and incubation time (r = 0.73), although NAG did not increase significantly at 30 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗
PubMed1987

Presence of abundant filaments in apical caps of the nonciliated bronchiolar epithelial (Clara) cells.

The nonionic detergent Triton X-100 has often been used for the extraction of cytoplasmic materials. We used the detergent in a vascular perfusion medium when preparing rat lung in order to observe the cytoskeleton of the nonciliated bronchiolar epithelial (Clara) cells. To eliminate some cytoplasmic materials selectively and to maintain good fine cell structure simultaneously, the lungs were perfused sequentially with the detergent (0.2% Triton X-100) alone for 2 min, with a mixture of low-concentration (0.1%) glutaraldehyde and detergent (0.2% Triton X-100) for 15 min, and finally with 2.5% glutaraldehyde for 5-10 min. After fixation, the nonciliated bronchiolar epithelial (Clara) cells were observed by scanning and transmission electron microscopy. At the apical region of the cells, there were central cytoplasmic protuberances (apical caps) filled with microfilaments. These filaments were bound at one end to the cytoplasmic side of the cell membrane and ran into the interior of the cytoplasm at the other end. As a control, the Clara cells were observed by transmission electron microscopy after perfusion with 2.5% glutaraldehyde solution. The luminal surfaces of the cells were covered with short, thick microvilli. The apical caps also had microvillus-like protrusions. These results suggest that the apical cap is not an apocrine droplet but rather is a stable structure involved in the function of the Clara cells.

Actin Cytoskeleton↗
PubMed1987

Smoke inhalation injury from newer synthetic building materials--a patient who survived 205 days.

A 25-year-old factory worker sustained inhalation injury and 2 per cent deep burns while fighting a fire in his factory (LSI factory) which was made of new synthetic building materials. He became unconscious and inhaled noxious substances from the smoke. Although he survived the acute stages following injury, his pulmonary function subsequently deteriorated with a damaged trachea and bronchi, repeated attacks of pneumonia, atelectasis, pneumothorax and lung fibrosis, leading to death with hypercapnia (PaCO2 more than 100 mmHg) after 205 days in hospital. Autopsy revealed scarring contraction and dilatation of the trachea and bronchi, acquired bronchiectasis, lobular pneumonia, bleeding, hyperaemia and oedema of the lungs. Systemic administration of corticosteroids was only transiently beneficial in reducing the increased airway resistance.

Adult↗
PubMed1987

Protective effect of vitamin E against lipoperoxides in developing rats.

Pregnant rats were fed a vitamin E-supplemented diet, and blood and liver tissue concentrations of lipoperoxides were determined in fetuses and newborn rats. For comparison, a standard diet and a vitamin E-deficient diet were given to different animal groups. Fetal rats of all three groups showed very low blood and liver tissue levels of lipoperoxides, and there were no apparent intergroup differences. However, the levels increased sharply immediately after birth in the vitamin E-deficient rats, with the blood level being 4 times greater than in the other groups 10 days after birth, and the liver level 6 times greater than in the other groups 3 days after birth. Thus, vitamin E was revealed to be an important protective factor against abnormal synthesis and accumulation of lipoperoxides in liver tissues, particularly during the early stages after birth.

Aging↗
PubMed1987

Lipid peroxidation and vitamin E levels during pregnancy in rats.

The present study examined pregnancy-related changes in the level of lipoperoxides and antioxidative substances such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) and vitamin E in the maternal and fetal serum, liver, lungs, and placenta using Wistar rats. Pregnant rats fed a standard diet (control animals) showed an increase of lipoperoxides in the blood to a level 3 times greater than the non-pregnant level. When the rats were fed a vitamin E-deficient diet, lipoperoxides were produced in much greater amounts. Fetal blood also contained greater concentrations of lipoperoxides by the use of a vitamin E-deficient diet. However, liver and lung tissues contained lipoperoxides in essentially constant concentrations throughout non-pregnancy and pregnancy. Fetal liver and lung tissues showed higher concentrations than the maternal concentrations. Fetal blood and tissue concentrations of vitamin E reflected the maternal concentrations, and the values in vitamin E-deficient animals were as small as 0.1-0.2 of the values in normally fed animals. As a protective factor against lipid peroxidation, SOD was slightly increased in the liver tissues of pregnant control animals, but catalase and GSH-Px were significantly decreased in the organ. A similar tendency was observed in vitamin E-deficient animals.

Animals↗
PubMed1986

Intra- and inter-nephron heterogeneity of ammoniagenesis in rats: effects of chronic metabolic acidosis and potassium depletion.

In order to determine intra- and inter-nephron heterogeneity of ammoniagenesis, ammoniagenic activity in microdissected nephron segments of control, acidotic and potassium (K)-depleted rats was examined. Intranephron distribution of ammoniagenic activity in control rats revealed the highest amount at the second segment of the proximal tubule (S2). Chronic metabolic acidosis induced ammoniagenesis markedly at the first segment of the proximal tubule (S1) by 235% and the thick ascending limb of Henle's loop by 198% and moderately at the S2 by 49%. K-depletion increased ammonia production significantly in the S1 by 298% and the S2 by 107%, which is a pattern quite similar to the result of chronic metabolic acidosis. Ammonia production in K-depletion was also increased in the cortical and medullary collecting tubule by 71% and 102%, respectively, probably due to increases in protein amounts (41% and 158%, respectively) there. To evaluate inter-nephron heterogeneity of ammoniagenesis, ammonia formation from glutamine in the S1 of superficial (SF) and juxtamedullary (JM) nephrons was examined. Although there was no difference in ammonia production between SF-S1 and JM-S1 in control rats, ammonia production in SF-S1 was significantly higher than that in JM-S1 in both metabolic acidosis and K-depletion. From these studies, we conclude: The increase of ammonia production in the proximal tubule was quite similar in both acidosis and K-depletion, suggesting that the main trigger of ammoniagenesis in both conditions might be a reduction of intracellular pH. SF-S1 was the nephron most reactive to acidosis and K-depletion. JM nephrons could be considered to be important not for ammonia production but for ammonia secretion.

Acidosis↗
PubMed1986

Selective inhibition of stimulation responses of neutrophils by membrane modulators.

Polymorphonuclear leukocytes undergo a series of morphological and biochemical changes in response to various chemical stimuli. Transmembrane potential change is an early event that follows stimulation and membrane depolarization may act as a trigger for superoxide generation. To determine if there is a correlation between membrane depolarization and superoxide generation, we investigated the effects of different membrane modulators on stimulus-dependent depolarization. The membrane modulators mepacrine, chlorpromazine and cepharanthine inhibited the superoxide generation produced by chemotactic peptide, FMLP, and/or digitonin in neutrophils. Inhibitory profiles of the activation parameters, however, demonstrate that membrane depolarization is not associated with superoxide generation: FMLP-induced depolarization was inhibited by the modulators tested and was accompanied by the suppression of superoxide generation, but the depolarization produced by digitonin was stimulated somewhat by these drugs. Our results indicate that receptor-mediated membrane depolarization is not a necessary event for the activation of superoxide generation by digitonin.

Animals↗
PubMed1986

Fluorescence and electron microscopic study of intracellular F-actin in concanavalin A-treated and cytochalasin B-treated Ehrlich ascites tumor cells.

To investigate the involvement of actin filaments in concanavalin A (Con A)-induced cap formation and cytochalasin B (CB)-induced zeiotic knob migration, the distribution of F-actin was studied in Con A-treated and CB-treated Ehrlich ascites tumor cells (EATC) by fluorescence microscopy using heavy meromyosin conjugated with a fluorescent dye, N-(7-dimethylamino-4-methylcoumarinyl) maleimide, (DACM-HMM). In non-treated cells, the diffuse fluorescence of DACM-HMM was observed in the cytoplasm, particularly intensely under the plasma membrane and around the nucleus. In Con A- and CB-treated cells, the fluorescence was seen at Con A-induced-capped and CB-induced-knob-accumulated regions. This fluorescence was more intense in CB-treated cells. To study the actin filaments in these fluorescent regions more clearly, the soluble components of the cells were eliminated by treatment with Triton X-100 or saponin solution containing a low concentration of glutaraldehyde, and the detergent-treated and saponin-treated cells were observed under a transmission electron microscope. Concentrated actin filaments were observed directly beneath the Con A-induced capping area and CB-induced zeiotic knob-accumulation area. The area of concentrated actin filaments appeared to correspond to the electron dense area observed in the identical region in the cells fixed without detergent treatment. More actin filaments were observed in CB-treated cells than in Con A-treated ones.

Actins↗
PubMed1985

Effects of proteinase inhibitors on preimplantation embryos in the rat.

Proteinase inhibitors of microbial origin were injected into the uterine horns of mated rats at 14:00 h on Day 5 of pregnancy (spermatozoa in vaginal smear = Day 1), and 5 or 6 h later the embryos were flushed from the horns and examined. Chymostatin and alpha-MAPI, inhibitors of chymotrypsin-like serine proteinase and thiol proteinases, as well as thiolstatin, an inhibitor of thiol proteinases, significantly inhibited embryo growth. The inhibitory activity of alpha-MAPI on embryonic growth was distinctly greater than that of thiolstatin, although the ID50 values of the two inhibitors to papain are similar. Antipain and leupeptin which are inhibitors of trypsin-like and thiol proteinases, and talopeptin, an inhibitor of metal proteinases, significantly interrupted the removal of the zona pellucida from expanding blastocysts. These results suggest that (1) a chymotrypsin-like proteinase seems to be important to the growth of the embryo, (2) a thiol proteinase may participate in embryonic growth, and (3) a trypsin-like proteinase and a metal proteinase are likely to participate in zonalysis.

Animals↗
PubMed1984

Prevalence of possible adult T-cell leukemia virus-carriers among volunteer blood donors in Japan: a nation-wide study.

A nation-wide survey of carriers of adult T-cell leukemia virus (ATLV) detected as anti-ATLA (ATLV-associated antigens) in volunteer blood donors was made in Japan. A total of 200 sera from donors between 40 and 64 years of age, collected in each of 64 blood centers located in eight districts, were tested for anti-ATLA by an indirect immunofluorescence test. The highest rate (8%) of seropositive donors was found in Kyushu and lower rates of 0.3 to 1.2% in other districts. However, the positive rate varied considerably in different localities even within districts with a high or low seropositive incidence. Further studies of all the donors (16 to 64 years old) in eight centers in Kyushu demonstrated two facts: (1) that the frequency of seropositive donors increased with age, and (2) that four centers in this district showed distinctly high incidences of seropositive donors, while the other four centers showed low incidences. The seropositive rate among all donors was estimated to be about 3% in Kyushu and 0.08 to 0.3% in all other districts.

Adolescent↗
PubMed1984

Inhibition of in-vitro fertilization of hamster oocytes by a thiol proteinase inhibitor.

Amongst the proteinase inhibitors tested, thiolstatin, a specific inhibitor for the thiol proteinases, leupeptin and antipain, both specific inhibitors of serine- and thiol-proteinases, strongly reduced fertilization of hamster oocytes in vitro. These results suggest the possible involvement of thiol proteinase(s), as well as acrosin, in the fertilization process. A possible role for thiol proteinase in sperm adhesion to the zona pellucida is proposed.

Animals↗