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Biomedical subjects

A Mizuno

Publications and source records attributed to A Mizuno.

At least 217 records · Page 12Linked to original sources
PubMed1990

Changes in alpha-tubulin and actin gene expression during optic nerve regeneration in frog retina.

The optic nerve of the bullfrog was transected and the regeneration process was investigated. We previously reported that alpha-tubulin mRNA in the retina increased to a maximum 1-2 h after optic nerve transection with no specific change in actin mRNA. In the present investigation, we examined the long-term effect of optic nerve transection. Northern blot analysis revealed that alpha-tubulin mRNA increased again gradually after the rapid and transient increase and actin mRNA increased to a maximum at 7 days (more than twofold compared to the control retinas). The period during which actin mRNA reaches a maximal increase almost corresponds to the time lag between the axotomy and the initiation of axonal outgrowth. The main cytoskeletons of neuronal growth cones have been shown to consist of actin-containing microfilaments. Therefore, the transient increase of actin mRNA may have a relationship to the initial outgrowth of axons. On the other hand, the rapid and transient increase of alpha-tubulin mRNA observed in our previous studies is probably one of the initial responses of retinal ganglion cells to the axotomy, and the gradual increase in alpha-tubulin mRNA observed in this study can probably be interpreted as provision of the structural materials necessary for axonal elongation.

Actins↗
PubMed1990

Raman study of the lenses of spontaneously-occurring and streptozotocin-induced diabetic rats.

The WBN/Kob rat is an animal model of spontaneously occurring diabetes only in males at the age of around one year. The diabetic cataract develops about a half year after the onset of diabetes. Using laser Raman spectroscopy we monitored WBN/Kob rat lenses which had chronic hyperglycemic stress and streptozotocin-induced diabetic rat lenses which showed relatively acute cataract formation. WBN/Kob rat lenses revealed a marked increase in the lens water content only in the cortical portion. On the other hand, streptozotocin-induced diabetic rat lenses showed a pronounced increase in the lens water content both in the cortical and the nuclear portion.

Animals↗
PubMed1990

[Effect of controlled freezing-point storage of hearts--combined effect of controlled freezing-point storage and verapamil].

Controlled Freezing-point Storage (CF Storage) is a new method of preserving foods in minus non-frozen temperature range. Therefore, the authors tried to apply this method to organ preservation. We investigated the effect of controlled freezing-point storage of hearts on ventricular function in isolated perfused rat heart (male, Sprague dawley strain, body weight about 300 g), and the combined effect of controlled freezing-point storage and Verapamil (0.5 mg/l). The hearts were perfused by working heart mode for 10 min, and received infusion of cardioplegic solution which was followed by 4 hours of cardiac arrest. The hearts were stored for 4 hours in Euro-Collins solution at 4 degrees C (4 degrees C group) and minus non-frozen temperature (CF storage group), and were stored for 4 hours in Euro-Collins solution containing Verapamil at minus non-frozen temperature (CF-Ve storage group). Then, the aerobic reperfusion by working heart mode was continued for an additional 30 min. The recovery rate of cardiac output was 33.5%, 62.5% and 74.2% respectively of the preischemic value in 4 degrees C group, CF storage group and CF-Ve storage group. The recovery rate of cardiac output in 4 degrees C group was significantly lower than that in CF storage group and CF-Ve storage group (p less than 0.01), and significant difference was noted between CF storage group and CF-Ve storage group (p less than 0.05). ATP activity after 4 hours of cardiac arrest was 13.9 micrograms/mg, 18.7 micrograms/mg and 18.3 micrograms/mg in 4 degrees C group, CF storage group and CF-Ve storage group respectively. ATP activity after 4 hours of cardiac arrest in 4 degrees C group was significantly lower than that in CF storage group and CF-Ve storage group (p less than 0.05). These data suggest that CF storage of hearts has a protective effect against an ischemic insult upon myocardial cell during hypothermic cardiac arrest, and the best metabolic and functional protection appeared when the hearts were stored in Euro-collins solution containing Verapamil at minus non-frozen temperature.

Animals↗
PubMed1990

[Metastatic tumors of the gingiva--report of 3 cases].

Metastatic tumors to the oral region are uncommon and most are located in the mandible, with only a few in the soft tissue of the oral cavity. A review of the literature has revealed only 63 cases of a gingival soft tissue metastases. The prevalent primary site are the lung, the liver and the kidney in that decreasing order. Reported are two lung carcinomas and an esophageal carcinoma all showing a metastases to the gingival soft tissue. The primary lesions of two lung carcinomas were diagnosed after the detection of the gingival lesions. In all cases the diseases had disseminated when the gingival metastases were diagnosed. The longest survival time was only 4 months. The prognosis for such cases is poor, but early diagnosis and treatment is essential in order to prevent the pain and discomfort associated with the ulceration, the infection, and the local tissue destruction by the lesions.

Adenocarcinoma↗
PubMed1990

[A case of double bronchogenic cysts in the mediastinum].

A 42-year-old house wife had suffered from abnormal mass lesion in the right pulmonary hilum on her chest X-ray film. MRI showed another mediastinal mass between IVC and descending aorta with high T1 and T2 intensity. Thoracic CT done before MRI missed the latter lesion because only upper mediastinal scanning had been performed. At operation subcarinal and right paraesophageal cysts were successfully removed. Histological examination of the subcarinal cyst showed ciliated pseudostratified columnar epithelium lining, and its thin wall consisted of partly smooth muscle bundle, lymph node, calcification, inflammatory cell infiltration and hemorrhage. The paraesophageal cyst lined by a ciliated pseudostratified columnar epithelium, and the wall consisted of mostly fibrous connective tissue with partly smooth muscle bundle. Although the both cysts were diagnosed as bronchogenic origin, definitive bronchial glands and cartilage could not be recognized. The postoperative course was uneventful. This is the first case report of mediastinal double bronchogenic cysts appeared in the Japanese literature.

Bronchogenic Cyst↗
PubMed1989

Inhibitory action of gliclazide on platelet functions.

Gliclazide (GC), an oral hypoglycemic agent, inhibits platelet functions, but its effective concentration is reported to be much higher in vitro than in vivo. To determine why, we compared its inhibitory effect measured by impedance aggregometry using citrated whole blood with that measured by turbidometry using platelet-rich plasma. In addition, to see how GC inhibits platelet functions, we examined its effects on arachidonic acid metabolism in platelets in an in vitro system. Impedance aggregometry was found to be more sensitive than turbidometry for detecting the inhibition of platelet aggregation, and revealed significant inhibition at 1 x 10(-4) M GC. GC reduced the amount of prostaglandin I2 (PGI2) needed to inhibit ADP-induced platelet aggregation and the adhesiveness of platelets to a rabbit vessel wall after their preincubation with 1 x 10(-3) M GC for 10 min. GC (1 x 10(-4) -1 x 10(-2) M) had no effect on platelet cyclo-oxygenase activity. GC inhibited thromboxane A2 (TXA2)-induced platelet aggregation, but had no effect on the aggregation triggered by addition of mixtures of arachidonic acid (AA) and inhibitors of key enzymes regulating various steps of AA metabolism in platelets. GC had no significant effect on PGI2-stimulated cyclic AMP (cAMP) production in platelets. These results show that the difference in the effective concentrations of GC reported to modulate platelet functions in vivo and in vitro is partly due to differences in the methods used to evaluate its effect: turbidometry evaluates platelet aggregability, but not other platelet functions modulated by GC in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1989

c-Fos mRNA induction under vitamin B6 antagonist-induced seizure.

c-Fos mRNA expression was studied in mouse brain after vitamin B6 antagonist-induced seizure. The vitamin B6 antagonists used were hydrazine, thiosemicarbazide, penicillamine and deoxypyridoxine. Only deoxypyridoxine was effective in increasing c-fos mRNA and c-fos protein expression in nerve cells. The other 3 antagonists had levels of c-fos mRNA below or equal to basal level. The seizure activity induced by several vitamin B6 antagonists resulted in different effects on c-fos gene expression.

Animals↗
PubMed1989

Phase I study of Y-20811, a new long-acting thromboxane synthetase inhibitor by oral administration.

The safety, pharmacological action and pharmacokinetics of the thromboxane (TX) synthetase inhibitor Y-20811, a prospective medication for ischemic vascular disorder, were investigated in Phase I clinical trials in which single and repeated doses were administered orally to 32 healthy adult male volunteers. In the single-dose study, subjects were given single doses of 2.5, 5, 10, 25, 50, and 100 mg; in the repeated-dose study, a single dose of 50 mg was administered daily for 5 days. In the repeated-dose study, slight elevation of liver function test parameters in 1 subject was observed, but throughout the trials, no abnormality attributable to the test drug was found in other routine laboratory tests, subjective and objective findings, vital signs (blood pressure, pulse rate, body temperature, respiration rate), ECG, or bleeding time; nor did any finding indicate a problem concerning the safety of Y-20811. In both single- and repeated-dose studies, inhibition of the serum TXB2 production and an increase in the 6-keto-prostaglandin F1 alpha production during whole-blood coagulation, and inhibition of arachidonic acid-induced platelet aggregation were observed from 1 hour after administration of Y-20811. The duration of these actions was long, the former two lasting 168 hours (1 week) and the latter 48-72 hours or more. Slight inhibition of adenosine diphosphate-induced secondary platelet aggregation was also observed. The maximum plasma concentration time (tmax) of Y-20811 was 0.5-1.1 hours. The initial-phase half-life (t1/2 alpha) was 0.8-1.1 hours and the final-phase half-life (t1/2 beta) was 4.7-9.2 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Selection of mouse preimplantation embryos carrying exogenous DNA by polymerase chain reaction.

A polymerase chain reaction (PCR) system to detect transgenes in mouse preimplantation embryos was employed so that transgenic embryos could be selected before they were transferred to recipient mice. The selection system involves bisection of morulae, selection of the half-morulae containing target sequences within 7 hr, and culture and transfer of the sister half-morulae. PCR analysis of morulae derived from transgenic mice confirmed that the PCR system was reliable. However, five of 41 implanted embryos derived from PCR-positive morulae did not contain the transgenes. Also, one of 28 implanted embryos from PCR-negative morulae were transgenic. The selection system was applied to fertilized mouse eggs into which pSV2-gpt-gE1A DNA was injected. The injected DNA was detected in 30 of 84 morulae derived from the microinjected eggs. All seven implanted embryos developed from PCR-negative morulae had no detectable amount of transgenes, and one of two successfully implanted embryos from PCR-positive morulae was transgenic.

Animals↗
PubMed1989

Postoperative infection prophylaxis for upper gastrointestinal tract surgery--a prospective and comparative randomized study of cefoxitin and ceftizoxime.

A prospective and randomized clinical study was conducted in order to compare cefoxitin (CFX) and ceftizoxime (CZX) as prophylactic antibiotics. Two hundred and three consecutive cases of elective upper gastrointestinal tract surgery, performed at our institute between January, 1983, and March, 1986, were entered in the trial. The patients were assigned randomly, before surgery, to the CFX or to the CZX group. Two grams of the assigned antibiotic was first administered during surgery and then continued at a dose of 1 gram, every 8 hrs for a total of 4 days. One patient was withdrawn from the study due to an allergic reaction. Both groups were comparable in sex, age, underlying disease, diagnosis, operation, and preoperative laboratory data. There were 18 infections related to the operation in the CFX group, while there were only 3 in the CZX group (p less than 0.001). The number of unrelated infections in each group was 6 and 6 respectively (NS). No special differences were found between the two groups regarding the kinds of microorganisms isolated, and no significant differences were seen in the adverse effects of either antibiotic. Our study demonstrated that ceftizoxime was more efficient than cefoxitin in preventing postoperative infection, following upper gastrointestinal tract surgery.

Adult↗
PubMed1989

Technical modification of aortic valve replacement in aortitis syndrome--report of a case.

In patients who have aortitis syndrome associated with aortic regurgitation, aortic valve replacement (AVR) is frequently complicated by perivalvular leakage (PVL). A 47-year-old male with aortitis syndrome and severe aortic regurgitation was treated by AVR, modified in such a way as to prevent PVL. The aortic cusps were not resected and were placed between Teflon pledgets and the aortic annulus. We believe that this technique is useful for preventing PVL in patients with aortitis syndrome in which the aortic annulus is severely inflammed.

Aortic Arch Syndromes↗
PubMed1989

Reduction and fixation of jaw fractures using acrylic splints.

This paper proposes the criteria for application of acrylic splints in the treatment of various types of maxillofacial fractures. These were based mainly on the number of remaining teeth that are important for the restoration of occlusion. The acrylic splints studied consisted of intermaxillary, lingual and labiolingual types that hold a dental arch and a cap type that covers a dental arch. It was found that the intermaxillary type was best indicated for the loss of multiple teeth, the lingual type for the predicted intraversion of bone fragments and the labiolingual as well as cap types for the deciduous or mixed dentition. Clinical application based on the above standard, which was attempted in our 60 patients, produced successful results. In addition, the usefulness of these acrylic splints as an intraoral apparatus was discussed.

Acrylic Resins↗
PubMed1989

Dihydropyrimidines: novel calcium antagonists with potent and long-lasting vasodilative and antihypertensive activity.

The novel calcium antagonists 3-N-substituted-3,4-dihydropyrimidines 1 and 9 and 3-N-substituted-dihydro-pyrimidin-2(1H)-ones 8 were regioselectively synthesized in good yields. Compounds 1 [especially 1s [R1 = (CH2)2N(benzyl)(2-naphthylmethyl), R2 = i-Pr, X = 0-NO2] and 1t [R1 = (CH2)2N(benzyl)(3,4-dichlorobenzyl), R2 = i-Pr, X = 0-NO2]] exhibited not only more potent and longer lasting vasodilative action but also a hypotensive activity with slow onset as compared with dihydropyridines. Moreover, some dihydropyrimidines [1q [R1 = (CH2)2N(benzyl)(3-phenylpropyl), R2 = CH2(cyclopropyl), X = 0-NO2], 1s, and 1t] were weaker in blocking atrioventricular conduction in anesthetized open-chest dogs and less toxic than the dihydropyridines.

Animals↗
PubMed1989

Determination of caffeine in saliva by high-performance liquid chromatography: new sampling method for saliva using filter paper.

We report an assay method for the determination of salivary caffeine concentrations by high-performance liquid chromatography. A simple, new method for collecting mixed saliva using a piece of filter paper has been developed. An arbitrary amount of saliva is absorbed and a fixed amount of internal standard is added. The mean coefficient of variation of measurements repeated by changing both volumes absorbed and caffeine concentrations of saliva was 5.6% with this method. The detection limit was determined to be 0.5 microgram/ml. Precision of measurements and recoveries did not depend upon the volume of saliva absorbed. Four volunteers were given a capsule of 230 mg caffeine, and saliva was collected by the ordinary method using chemical stimulation with citric acid and by our filter paper absorption methods; the methods were compared. Salivary caffeine concentrations were always lower than plasma concentrations, and there were no big differences between two methods, although salivary concentrations measured by our method was higher, with a significant difference at 1.5 h after dosing. From the practical viewpoint this method would be convenient and sufficiently accurate.

Adult↗
PubMed1989

[Postoperative enterocolitis and current status of MRSA enterocolitis--the result of a questionnaire survey in Japan].

There is a trend of increase in the number of Staphylococcus aureus infection recently, and postoperative enterocolitis due to methicillin resistant strains is appearing. Because of this, a nation wide questionnaire survey on postoperative enterocolitis was conducted to clarify the status since 1980. Of the 875 major surgical institutes to which we sent the questionnaire, 370 (42.3%) replied and 67 case reports were obtained from 25 institutes. Twenty published reports were added to this and a total of 87 cases were evaluable. The number of postoperative enterocolitis increased after the year 1985, and those resulting from MRSA infection were more frequent in the northern half of Japan including the Kanto area. It was more frequent in males and the mean age was 57.9. Their onset was sudden, beginning with diarrhea and/or fever between the second and fifth postoperative days. In most of the cases, the cephalosporin group of antibiotics, especially of the third generation, were administered preceding the enterocolitis. Six of cases (24%) did not survive, and in some of the institutes they were considered to be hospital infections, as they appeared consecutively between a short period of time.

Adult↗
PubMed1989

[Inhibition of thromboxane production might ameliorate liver blood flow in shock].

UNLABELLED: We investigated whether thromboxane (TX), a vasoconstrictor, contributes to liver disturbance in shock by reducing liver blood flow. SUBJECTS AND METHODS: experimental groups: Sham, Et: endotoxin 4mg/kg, BDL + Et: bile duct ligation with Et, OKY. BDL + BDL + Et with infusion of OKYO46 (TX synthetase inhibitor) 5mg, HT: three days after 70% hepatectomy, OKY. HT: HT receiving OKYO46. We evaluated prostanoid and morbidity in hepatectomized cases. MEASUREMENT: TX, liver phospholipid, liver blood flow, endotoxin. RESULTS: Higher TX levels in blood and liver, and reduced liver phospholipid and liver blood flow in BDL + Et returned close to sham by OKYO46. High blood endotoxin in HT decreased by OKYO46. Intraoperative blood losses in cases with postoperative intraabdominal infection or hepatic failure were greater than those without complication. Hepatectomized cases with intraabdominal infection showed higher blood TX than those without complication. TX might be associated with decreased liver blood flow and with postoperative complication during shock. To reduce TX production would be beneficial in shock by ameliorating liver blood flow.

Animals↗