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Biomedical subjects

T Sakurai

Publications and source records attributed to T Sakurai.

At least 487 records · Page 27Linked to original sources
PubMed1992

High survival of rabbit morulae after vitrification in an ethylene glycol-based solution by a simple method.

Rabbit morulae were exposed to a vitrification solution-modified PBS [PB1] medium containing 40% ethylene glycol + 18% Ficoll + 0.3 M sucrose (EFS) for 2, 5, or 10 min at 20 degrees C and were vitrified in liquid nitrogen. When morulae were rapidly warmed, 96% had an intact zona pellucida. When embryos were cultured after removal of the mucin coat, high proportions of them formed blastocoel (79-100%), but the percentage of embryos developed to fully expanded blastocysts decreased with increased exposure time 87%, 40%, and 17%). The survival rate of morulae vitrified after removal of the mucin coat was lower than that of mucin-intact embryos. To assess the development potential in vivo, 131 embryos were vitrified after 2 min of exposure to EFS solution; all the embryos were recovered and 120 were transferred to recipients without removal of the mucin coat, resulting in 78 (65%) full-term fetuses or young. This simple method, which yields high survival both in vitro and in vivo, will be of practical use for vitrifying rabbit embryos.

Animals↗
PubMed1992

Survival of mouse morulae vitrified in an ethylene glycol-based solution after exposure to the solution at various temperatures.

Mouse morulae were exposed in one step to a vitrification solution (EFS, a modified PBS containing 40% ethylene glycol, 18% Ficoll, and 0.3-M sucrose) at various temperatures, then cooled rapidly in liquid nitrogen, and then warmed rapidly. All of the embryos exposed to the EFS solution for 0.5 min at 25 degrees C before vitrification developed in culture. However, survival rates were lower if the duration of exposure was prolonged to 2, 5, or 10 min. At lower ambient temperatures (20, 10, and 5 degrees C), high survival rates were associated with longer exposure to the EFS solution. The toxicity of the EFS solution was also lower at lower temperatures. The toxic injury of morulae was manifested as decompaction of the blastomeres. Among the three additives in the EFS solution, ethylene glycol, which can cross cell membranes, was responsible for the toxicity. The results show that the optimum time for exposure of the embryos to the EFS solution before rapid cooling varies with the ambient temperature, i.e., 0.5 min at 25 degrees C, 0.5-5 min at 20 degrees C, 2-5 min at 10 degrees C, and 2-10 min at 5 degrees C. If they are exposed for an optimum period, almost all mouse morulae can survive vitrification (94-100%).

Animals↗
PubMed1992

Increased lung endothelin-1 production in rats with idiopathic pulmonary hypertension.

The role of endogenous circulating or locally produced endothelin-1 (ET-1) in pulmonary hypertensive states is unknown. To investigate this we measured ET-1 levels and preproendothelin-1 (prepro-ET-1) mRNA expression at various ages in control Sprague-Dawley (SDR) rats and in fawn-hooded rats (FHR), a strain which develops idiopathic pulmonary hypertension. Although serum ET-1 levels were similar in SDR and FHR, we found twofold increases in FHR whole lung homogenate ET-1 levels by radioimmunoassay. Coexisting threefold increases in preproET-1 mRNA expression were found in FHR lungs by densitometric analysis of Northern blots and by filter hybridization, suggesting the increase in lung ET-1 was due to enhanced intrapulmonary production of the peptide. To test whether the increase in lung preproET-1 mRNA was primary or secondary to established pulmonary hypertension, we compared preproET-1 mRNA expression prior to development of pulmonary hypertension in fetal (19 day gestation) and neonatal (5 day old) FHR and SDR. Despite similar right ventricular size in SDR and FHR, preproET-1 mRNA was already elevated in neonatal FHR lungs. Furthermore, we found no increase in lung preproET-1 mRNA or ET-1 levels in adult SDR with an equivalent degree of pulmonary hypertension due to chronic hypoxia, implying that the increases in ET-1 production in FHR were not a common consequence of all pulmonary hypertensive states. The functional significance of these observations remains unclear but raises the possibility of a role for ET-1 in the pathophysiology of pulmonary hypertension in the FHR.

Animals↗
PubMed1992

Comparison of lipids, apoproteins and associated enzyme activities between diabetic and nondiabetic end-stage renal disease.

Lipids, apoproteins and associated enzyme activities in type 2 diabetic end-stage renal disease (ESRD) were compared with that in nondiabetic ESRD and normal controls. Of the 40 uremic patients with non-insulin-dependent diabetes mellitus, 20 patients were receiving stable continuous hemodialysis treatment (CHT). Of the 39 patients with nondiabetic ESRD, 21 were undergoing CHT. Patients with nondiabetic ESRD exhibited elevated levels of serum triglyceride and a marked reduction in high-density-lipoprotein (HDL) cholesterol. Concentrations of serum apolipoprotein (Apo) C-3 were higher than in controls, whereas mean levels of serum Apo E were lower. The concentrations of serum Apo A-1 and Apo A-2 decreased with diminished lecithin: cholesterol acyltransferase activity. Lipoprotein lipase activity decreased in undialysed patients, and hepatic triglyceride lipase activity decreased significantly throughout the observation. Patients with diabetic ESRD exhibited elevated serum Apo B and normal serum Apo E levels, besides the lipid and Apo abnormalities observed in nondiabetic ESRD. Moreover, a prominent reduction in serum Apo A-1 was found in dialysed diabetic patients. The Apo B/Apo A-1 ratio was significantly higher in diabetic ESRD than in nondiabetic patients undergoing CHT. These results indicate that lipid abnormalities are accelerated in diabetic ESRD and may constitute a serious risk for the development of atherosclerosis.

Adult↗
PubMed1992

Microcirculatory characteristics in patients with Buerger's disease.

The most characteristic pathophysiologic change in Buerger's disease or thromboangiitis obliterans (TAO) is considered the breakdown of microcirculation in the extremity, but this has not yet been proven. The purpose of this study is to examine the damage of microcirculation in TAO objectively, by means of intra-arterial injection of two kinds of radioisotope. In 7 TAO and 4 infrainguinal arteriosclerosis obliterans (ASO) patients, thallium 201 chloride (201Tl) and 99mTc macroaggregated human serum albumin (99mTc-MAA) were administered through bilateral common femoral artery injections. In the planar image of the foot, rectangular regions of interest (ROIs) were placed on the foot muscles and toes. Normalized counts of 99mTc-MAA in each ROI were divided by that of 201Tl, and the result was defined as the microcirculation damage index, based on their different kinetics. The damage index of the foot muscle was not different between ASO and TAO, but that of the toe was lower in TAO than ASO patients. Lumbar sympathectomy was performed in 5 TAO patients, but it did not improve the damage index. It is concluded that there is breakdown of the microvascular defense system from the beginning of the disease, and critical ischemia make the regional cell function deteriorate as if a precursor to a trophic lesion. Lumbar sympathectomy did not immediately improve microcirculation.

Adult↗
PubMed1992

Mechanisms of pharmacokinetic interaction between propranolol and quinidine in rats.

In order to study the mechanism of propranolol-quinidine interaction, the effects of quinidine on propranolol pharmacokinetics were examined in male Wistar rats. The concurrent oral administration of quinidine (10 mg/kg) markedly increased the plasma concentration of propranolol (2.5 mg/kg), and the area under the propranolol concentration-time curve increased about 3.6-fold. These results are consistent with previous observations in man and indicate the possible usefulness of the male Wistar rat as an animal model for investigating the mechanisms of the drug interaction. When propranolol was given intravenously, a concurrent administration of quinidine increased the apparent distribution volume of propranolol, mainly by decreasing its plasma protein binding. However, the systemic clearance of propranolol was not significantly altered by quinidine. Thus, quinidine increased the availability of oral propranolol from 13.8 +/- 2.2 to 44.2 +/- 4.6% (p less than 0.01). Furthermore, quinidine delayed the elimination of propranolol from the isolated perfused rat liver. These results indicate that quinidine reduces the presystemic elimination of propranolol in the liver, thereby increasing its systemic availability after oral administration.

Animals↗
PubMed1992

Intravenously administered (1----3)-beta-D-glucan, SSG, obtained from Sclerotinia sclerotiorum IFO 9395 augments murine peritoneal macrophage functions in vivo.

Effect of intravenously (i.v.) or intraperitoneally (i.p.) administered (1----3)-beta-D-glucan, SSG, obtained from Sclerotinia sclerotiorum IFO 9395 on the murine peritoneal macrophage (PM) functions were examined. A single i.v. administration of SSG increased the number of PMs at a dose of 250 micrograms/mouse, and the peak appeared 4 d after administration. However, no special change was observed on peritoneal exude cell (PEC) populations. These PMs showed augmented lysosomal enzyme activity and the peaks appeared in 2 phases, on days 2 and 10. In contrast, SSG administered i.p. (250 micrograms/mouse) increased the number of PMs and enhanced the lysosomal enzyme activity of PMs from day 4, and a broad peak appeared until days 8--12. The populations of PECs were also changed by i.p. injection of SSG. Additionally, SSG administered i.v. enhanced phagocytic activity, H2O2 production and interleukin 1 (IL-1) production, and the kinetics of the activation differed depending on the activities. These data suggest that the effects of SSG on macrophage functions are different depending on administration routes, and there are some different mechanisms in the activation of macrophages in vivo by SSG.

Adjuvants, Immunologic↗
PubMed1992

Identification of the carboxymethyllysine residue in the advanced stage of glycated human serum albumin.

As an advanced stage of glycation, glycated human serum albumin (G-HSA; glucose content, 2 mol of 5-hydroxymethylfurfural equivalent/mol of HSA) was incubated at 37 degrees C up to 30 d in 0.2 M phosphate buffer, pH 7.4, with 100 microM Fe3+. G-HSA incubated for 30 d (G-HSA-30(Fe)) was subsequently hydrolyzed at 110 degrees C for 24 h in 6 N HCl. In the hydrolysate, N epsilon-carboxymethyllysine (CML) was identified by cochromatography with synthesized CML on an amino acid analyzer. pI of HSA (4.8) shifted to 4.5 in G-HSA. A more acidic fraction, pI 4.3, appeared in G-HSA-30(Fe). CML content (mol of CML/mol of HSA) of HSA and G-HSA was as follows; 0 in HSA, 0.2 in HSA-30(Fe), 0.4 in G-HSA and 1.5 in G-HSA-30(Fe) pI 4.3. The amino acid compositions also changed in lysine, arginine and tyrosine at the advanced stage of the reaction.

Arginine↗
PubMed1992

[Molecular pharmacology of endothelin in the cardiovascular system].

Endothelin-1 (ET-1), ET-2 and ET-3 are 21-amino acid peptides that act to stimulate contraction of many smooth muscle tissues including blood vessels, uterus, bladder, and intestine. In the case of each ET, the 21-amino acid bioactive form is produced from each precursor (referred to as big ET) via specific conversion between Trp-Val (ET-1, ET-2) or Trp-Ile (ET-3). Northern blot analysis of the mRNA for the ET isoform as well as determination of the peptide itself revealed that they are independently expressed in various tissues, indicating that each isoform may play separate physiological or pathophysiological roles. However, the vascular endothelial cells appear to produce only ET-1. Since ET-1 was first discovered, the majority of investigations so far reported have been concerned with this particular peptide. This review will focus on ET-1 with respect to the regulation of its biosynthesis in endothelial cells and its precise pharmacological actions on the cardiovascular system including the cerebral, coronary and renal circulations. Sub-classification of ET receptors was made from molecular biological, biochemical as well as pharmacological points of view. The signal transduction for mechanisms of action was also explained in detail.

Animals↗
PubMed1992

Antitumor activity of new antitumor substance, polyoxomolybdate, against several human cancers in athymic nude mice.

Antitumor polyoxomolybdates have been recognized in the course of study on the medical utilization of polyoxometalates, inorganic polymers of metal oxide. [NH3Pri]6[Mo7O24].3H2O (PM-8) was found as a representative of antitumor polyoxomolybdates. The growth suppressions of PM-8 against Co-4 human colon cancer xenografted under the subrenal capsule in cd-1 mice were equal or superior to that of 5-FU, MMC, ACNU, ADM and CDDP. Potent antitumor activity of PM-8 is also established against MX-1 human breast and OAT human lung cancer xenografted in athymic nude mice. Polyoxomolybdate is a new type of antitumor substance.

Animals↗
PubMed1992

Absorption and metabolism of pyridoxamine in mice. II. Transformation of pyridoxamine to pyridoxal in intestinal tissues.

The absorption of pyridoxamine from the intestine of the mouse was studied in whole animals. [3H]Pyridoxamine was orally administered and the distribution of isotope between the six recognized forms of vitamin B6 was determined in portal blood after the administration. When small doses (1.4 or 14 nmol) were administered, labeled pyridoxamine could hardly be found in the portal blood, although labeled pyridoxal and pyridoxal phosphate were found in the same blood. However, when a large amount (46 or 140 nmol) was given, a significant amount of labeled pyridoxamine was found with labeled pyridoxal and pyridoxal phosphate in the portal blood. These results suggest that a physiological dose of pyridoxamine is rapidly transformed to pyridoxal in the intestinal tissues and then released in the form of pyridoxal into the portal blood.

Administration, Oral↗
PubMed1992

[A report of two cases of cervical necrotizing soft-tissue infection].

Two recent cases of cervical necrotizing soft-tissue infection are herein presented. Case 1. A 52-year-old man with uncontrolled diabetes was hospitalized because of an erythematous swelling of the left side of his neck and high grade fever. Fetid yellowish pus exuded from the left parotid area. The swelling extended from the left temporal area to the left supraclavicular fossa, with necrosis of the parotid gland, sternocleidomastoid, masseter and a portion of the strap muscles. Wound cultures revealed Staphylococcus aureus and alpha-hemolytic streptococcus. No anaerobic bacteria were detected. Treatment consisted of intravenous administration of antibiotics, control of diabetes with insulin, and debridement of the necrotic tissue, which left an epidermal defect in the initially swollen area. Transfer of a forearm free flap was done after the growth of healthy granulation tissue over the affected area. Case 2. A 55-year-old woman with rheumatoid arthritis was transferred to our hospital after tracheotomy performed in another hospital because of dyspnea due to severe crepitant swelling of her cheeks and submandibular areas bilaterally, and her left temporal area. A copious amount of fetid pus exuded from the incisions made in the left temporal area, left cheek, and right submandibular area. There were bilateral diffuse rales. Culturing the pus revealed alpha-hemolytic streptococci, while MRSA and Pseudomonas aeruginosa were detected from cultures of sputum. No anaerobic bacteria were found. After intravenous administration of antibiotics, infected wounds and pneumonia were ameliorated, and necrotic subcutaneous tissue and fascia were debrided. The patient was discharged with a residual depression in her left cheek and a scar on her left temporal area.

Connective Tissue Diseases↗
PubMed1992

[Serum eosinophil cationic protein (ECP) and major basic protein (MBP) levels in patients prepared for asthma attack].

Serum ECP levels, serum MBP levels and blood eosinophil counts (Eo) were studied in patients prepared for asthma attack. Five severely asthmatic children were studied. Samples were taken just before their 33 times of home stay loading test. Serum ECP levels were significantly higher in the patients who suffered asthma attacks during their home-stay period than in those who did not. In addition, serum ECP levels were higher in the patients whose asthma attack started less than 12 hours after they returned home. However, there was no significant correlation either in serum MBP levels or peripheral eosinophil counts between these groups. These findings suggested that serum ECP levels increased in patients prepared for asthma attack.

Adult↗
PubMed1992

Marinesco-Sjögren syndrome with reduced cytochrome c oxidase in muscle.

The present study deals with the sisters of Marinesco-sjögren syndrome without parental consanguinity. Cranial MRI of sisters in a 0.5T superconducting magnet revealed the cerebellar hypoplasia or atrophy, especially in vermis and tonsils with dilatation of IVth ventricle. Microscopic findings of muscle biopsy indicated moderate variation of fibers with phagocytosis, rimmed vacuoles and no ragged red fibers with markedly decreased cytochrome C oxidase activity. 1H-NMR study of urine indicates the secondary decreased turnover rate in urea cycle due to high concentration of 3-hydroxy-n-butyrate.

Biopsy↗
PubMed1992

[The treatment of choice in deep vein thrombosis of the lower extremity].

Of 67 patients with acute deep vein thrombosis of the lower extremity (DVT), 43 patients were treated by venous thrombectomy and 24 patients were managed by conservative treatment. The clinical effect of thrombectomy was evaluated by analyzing follow-up results in the 2 groups. The cumulative incidences of pigmentation and stasis ulcer at the 5th year were 2.7% and 0% respectively in the thrombectomy group, and 24.3% and 10% respectively in the conservative treatment group. Pigmentation and stasis ulcer were significantly more frequent in the conservative treatment group (p < 0.01). It is concluded that venous thrombectomy is superior to conservative treatment to prevent late postthrombotic sequelae. Protein C, protein S and plasminogen were assayed in 40 DVT patients to determine the incidence of hypercoagulable state in DVT. Congenital deficiency or abnormality were found in 15 patients (37.5%). In such DVT patients with thrombophilia anticoagulant prophylaxis should be continued to decrease a risk of rethrombosis.

Adult↗