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Biomedical subjects

M Nakashima

Publications and source records attributed to M Nakashima.

At least 469 records · Page 26Linked to original sources
PubMed1989

Electrophysiological abnormalities and enhanced reperfusion arrhythmias in the isolated hearts of hyperthyroid rats.

1. The influence of hyperthyroidism on electrophysiological characteristics and on reperfusion arrhythmias was examined in rat hearts. 2. Electrophysiological studies were performed with glass microelectrodes, and the experiments on reperfusion arrhythmias were done in isolated perfused hearts. 3. Ventricular muscle from hyperthyroid rats was more prone than that from euthyroid rats to develop triggered activity under conditions believed to cause myoplasmic Ca2+ overload. 4. The severity of reperfusion arrhythmias was significantly enhanced in hyperthyroid preparations as compared with euthyroid ones. 5. The enhanced reperfusion arrhythmias in hyperthyroid rats were significantly reduced by propranolol (3 x 10(-7) M), lignocaine (1 x 10(-5) M) and verapamil (3 x 10(-8) M), but not by nadolol (3 x 10(-7) M) or prazosin (3 x 10(-7) M). 6. These results suggest that increased heart rate due to hyperthyroidism and responses mediated via either alpha- or beta-adrenoceptors were not dominant causes of enhanced reperfusion arrhythmias in hyperthyroid hearts. 7. The increased tendency to develop triggered activity which was observed in the electrophysiological study, may be one possible explanation of enhanced reperfusion arrhythmias in hyperthyroid hearts.

Action Potentials↗
PubMed1989

Dentin induction by implants of autolyzed antigen-extracted allogeneic dentin on amputated pulps of dogs.

Implantation of autolyzed antigen-extracted allogeneic (AAA) dentin matrix gelatin powder caused homeoinduction on amputated dental pulps. This event began with migration of spindle-shaped mesenchymal cells into the cavity on the amputated pulp. This was followed by proliferation of undifferentiated large cells concomitantly with vascular invasion and attachment of spindle-shaped cells and large cells to the AAA dentin. The adhering cells differentiated into osteodentinoblasts and/or preodontoblasts to form osteodentin matrix and predentin respectively. Osteodentinocytes and odontoblasts, then, formed osteodentin and tubular dentin. The healing of pulp dressed with inactivated AAA dentin using guanidine HCl was delayed. These results suggested that AAA dentin matrix powder may have chemotactic and mitogenic activity for undifferentiated mesenchymal cells and may provide a suitable scaffolding for fixation of these cells. Compartments of microenvironment formed by AAA dentin and the enveloping hard substances may play some role in differentiation into odontoblasts.

Animals↗
PubMed1989

Changes in plasma level of alpha-atrial natriuretic polypeptide (alpha-ANP) and responsiveness of the aorta to exogenous alpha-ANP subsequent to myocardial infarction in rats.

The changes in plasma level of alpha-atrial natriuretic polypeptide (alpha-ANP) and the relaxing responses to exogenous alpha-ANP of strips of rat aorta pretreated with methoxamine were examined at one, four and eight weeks after myocardial infarction induced by left coronary ligation. Responses to a beta-adrenergic stimulant, isoprenaline, and sodium nitroprusside of the vessel pretreated with high potassium were also evaluated up to twelve weeks. Plasma concentrations of immunoreactive alpha-ANP, which were measured at one, four and twelve weeks, were significantly elevated in rats with myocardial infarction (MI-rats) as compared with sham-operated rats (sham-rats). The relaxation responses of the aorta to exogenenous alpha-ANP in MI-rats were significantly reduced at one and four weeks as compared with sham-rats. The difference was, however, less obvious at eight weeks. The responses to isoprenaline tended to be reduced from the 1st week to the 12th week, and the difference was significant at eight weeks, whereas those to methoxamine and sodium nitroprusside were unchanged. It is concluded that the MI-rats are partially resistant to the vasodilating effects of alpha-ANP and isoprenaline without any change in responses to the alpha-stimulant and sodium nitroprusside, although these changes are transient.

Animals↗
PubMed1989

Reversal effect of thyroxine on altered vascular reactivity in diabetic rats.

The influence of thyroxine treatment on the altered reactivity of the isolated perfused mesenteric vasculature from streptozocin-induced diabetic rats was examined and compared with that of insulin. After 8 weeks of diabetes, the time when the decreased response to isoproterenol appeared, treatment with thyroxine reversed this decreased response to control levels. However, thyroxine replacement did not reverse the decreased responsiveness to norepinephrine, 5-hydroxytryptamine, acetylcholine, and isoproterenol after 12 weeks of diabetes. On the other hand, insulin replacement improved the vascular responsiveness to these agonists at 8 and 12 weeks. Insulin treatment also reversed the attenuated response to nerve stimulation found in diabetic rats, whereas thyroxine treatment did not improve it. Insulin treatment reversed the decreased plasma thyroid hormone levels similarly as thyroxine treatment. These results suggest that thyroid hormone deficiency is likely to be involved partly in the altered reactivity of the rat mesenteric vasculature at the early period of diabetes. On the other hand, adrenergic neuropathy is not induced by hypothyroidism.

Animals↗
PubMed1989

[Radiographic follow up examination on pulpotomy in primary teeth. Treatment with formocresol paste].

We conducted a radiographic follow up and discussion concerning 125 primary teeth (46 boys and 24 girls), which were random samplings from all primary teeth which had been treated by pulpotomy with Formocresol (Pulpac V) during the period from January 1980 to December 1985 at the Pediatric Dentistry Clinic of the School of Dentistry, Hiroshima University. For the follow up examination, we used only the radiograms which were radiographically available. The results obtained were as follows: 1) At the time of final follow up examination for each treated tooth, the number of teeth judged as being successful were 50 (40.0%) and 75 (60.0%) as being unsuccessful. In particular we observed especially many teeth judged as being unsuccessful during the period from 6 to 12 months and from 30 to 36 months after treatment. 2) In this investigation, we observed all the radiograms which had been taken at the recall after treatment, and therefore the number of cases examined was 247. According to the results at the time of each follow up examination, unsuccessful cases were more numerous during the period from 30 to 36 months. 3) According to the location of the treated teeth and the age at the time of treatment, abnormal findings appeared in the majority of the unsuccessful cases within 18 months after treatment. Unsuccessful cases were more numerous for the lower first deciduous molars. Successful cases of patients aged 6 years, when pulpotomy had been performed, were more numerous. 4) Of 75 teeth judged as being unsuccessful, 24 showed internal root resorption, 24 abnormal root resorption, 51 loss of lamina dura integrity and 53 alveolar bone resorption in the periapical and/or furcation areas.

Child↗
PubMed1989

[Clinical and radiographic follow up examination on direct pulp capping in primary teeth].

The purpose of this investigation was to evaluate direct pulp capping in primary teeth with calcium hydroxide agents. All utilized datas were selected from all the charts of the 3,675 patients at Pediatric Dentistry clinic of the School of Dentistry, Hiroshima University. The results obtained were as follows: 1) The number of all primary teeth where direct pulp capping, pulpotomy and pulpectomy were performed, was 2,511, and direct pulp capping was performed on 124 primary teeth (4.9%). Out of the 124 primary teeth, 100 were clinically evaluated. 2) At the time of the final follow up examination for each treated tooth, the ratio of teeth judged as being clinically successful were 94 (94.0%) and 6 (6.0%) as being unsuccessful. In the first year after treatment, the majority of unsuccessful cases were found. 3) We had many unsuccessful cases of anterior teeth on which composite resin and glassinomer cement had been filled after direct pulp capping. 4) Of 6 teeth judged as being clinically unsuccessful, 2 showed spontaneous pain, 1 discoloration of the tooth, 1 gingival swelling and 2 abscess formation. 5) Out of 100 primary teeth in the clinical examination, 66 became available for radiographic evaluation, and the ratio of teeth judged as being successful were 58 (87.9%) and 8 (12.1%) as being unsuccessful. During the two years following the treatment, we found most of unsuccessful cases.

Calcium Hydroxide↗
PubMed1989

[Intra-arterial injection of cisplatin suspension in lipiodol (LPS) for the treatment of advanced hepatocellular carcinoma (stage IV)].

We established a preparation method for the suspension of cisplatin in Lipiodol (LPS) and applied it by intra-hepatic artery injection for the treatment of advanced hepatocellular carcinoma. We defined that stage IV carcinoma as characterized by tumor spread more than one lobe (H4) or by tumor emboli in the major branches of the portal vein (Vp3) or by distant metastasis (M1). According to this definition, 20 patients of stage IV were treated by this therapy, and evaluated the survival using Kaplan-Meier method. A reduction in tumor size more than 25% was observed in 11 of 20 patients (55%). In 4 of these cases (20%), over 50% of tumor reduction was obtained. In 15 patients whose serum alpha-fetoprotein (AFP) levels were higher than 400 ng/ml, a decrease more than 50% was noted in 9 of the 15 patients (60%). Sixty per cent survival rate was obtained at 6 month. A statistical by significant difference was obtained in the survival patterns between this therapy and other intra-arterial chemotherapy. The factors that influenced on the survival significantly were AFP levels (over 10,000 ng/ml), Vp3 and M1. However, tumor size and intrahepatic metastasis, etc. were not significant factors. LPS therapy seemed to be effective to even stage IV hepatocellular carcinoma and could be applied further.

Carcinoma, Hepatocellular↗
PubMed1989

[The clinical study of fluconazole against pulmonary mycosis. Effects of fluconazole on pulmonary cryptococcosis and aspergillosis, and its pharmacokinetics in patients].

Effects on pulmonary cryptococcosis and aspergillosis and the pharmacokinetics of the new antimycotic agent, fluconazole, were examined. 1. Cases Pulmonary cryptococcosis: Two cases, 30 and 29 year-old men who were suspected of pulmonary tuberculosis by routine health examinations. Pulmonary aspergillosis: A 65 year-old man with collagen disease and a 62 year-old man with bacilli free cavities of tuberculosis. 2. Method Fluconazole was administered at a dose level of 400 mg/day per os for 2 to 4 weeks. One exception was the 65 year-old aspergillosis patient who was administered with fluconazole 50 mg/day for 4 weeks, 100 mg/day for 6 weeks then 400 mg/day for 4 weeks. Sera of the cases 1, 2 and 4 were harvested before, and 1/2, 1, 2, 4, 8 and 24 hours after administration of fluconazole on the 1st and the 7th day, and in every morning until the 9th day before administration and stored in a freezer. Serum fluconazole concentrations were determined at Pfizer Taito Laboratory. As pharmacodynamic parameters, T1/2, Tmax and Cmax were calculated. 3. Result Effects of fluconazole on 2 of the 2 cases with cryptococcosis were excellent. On the other hand, the effects on the aspergillosis were poor. The average Tmax was 2-4 hours. The average C maxs were 10.3 micrograms/ml on the 1st day and 30.6 micrograms/ml on the 7th day. Serum concentrations reached the plateau on the 5th-7th day, and the average C min (concentration before administration) was 21-23 micrograms/ml. Average T1/2s were 34.4 hours on the 1st day and 37.2 hours on the last (32th) day. 4. Conclusion Fluconazole may be regarded as the promising remedy for pulmonary cryptococcosis but not for pulmonary aspergillosis.

Adult↗
PubMed1989

[A case of miliary tuberculosis associated with ARDS, DIC and bilateral pneumothorax].

We reported a case of 64 a year-old male patient of miliary tuberculosis associated with ARDS, DIC and pneumothorax, who had a history of gastric ulcer and pulmonary tuberculosis. On admission his chief complaints were fever, fatigue, palpitation, appetite loss and weight loss, and most noticeable abnormalities were bleeding from the gastric ulcer and miliary shadow on the chest x-ray film with hypoxemia. On the day after admission to the hospital he was diagnosed as ARDS as he showed severe hypoxemia due to extensive tuberculous infiltration in bilateral lung fields, and treatment with antituberculous drugs and steroids were started. On the third hospital day DIC appeared on laboratory data, Gabexate mesilate (FOY) for DIC and respirator for ARDS were introduced. Two weeks later pulmonary infiltration, PaO2 and general condition were somewhat improved. On the 15th day after admission pneumothorax occurred on the right side, and on the 20th day on the left. Tube drainage of both pleural cavities, and instillation of OK-432 and Fibrinogen HT into the right pleural cavity were done, but it showed no effect. Two months after admission pouring Fibrinogen HT and thrombin into the left B1+2 and right B1 with cannula washing pipe through the instrument channel of bronchoscope was carried out. A few days later air leakage stopped and collapsed lungs were completely expanded. This method is effective in the case of incurable pneumothorax with pulmonary hypofunction.

Disseminated Intravascular Coagulation↗
PubMed1989

[Clinical investigation of pulmonary dirofilariasis with unusual abnormalities on chest roentgenograms].

The authors recently encountered three cases of pulmonary dirofilariasis with unusual abnormalities on chest roentgenograms. In case 1, with right upper and lower lobe masses and right pleural effusion, the right lower lobe mass and pleural effusion spontaneously disappeared one month after admission. In case 2, chest roentgenograms and chest CT scanning revealed a small mass with cavity formation. In case 3, with a right lower lobe mass and pleural effusion, steroid therapy resulted in disappearance of the mass and a remarkable reduction of pleural effusion. Human pulmonary dirofilariasis is a rare disease. In Japan, only 32, including our cases, have been reported in the literature of pulmonary dirofilariasis with unusual abnormalities on chest roentgenograms. The literature was reviewed.

Aged↗
PubMed1989

[A double-blind comparative study of intracoronary administration of GE-0943 and urokinase: multicenter study].

Coronary thrombolysis with plasminogen proactivator, GE-0943, was undertaken in patients with acute myocardial infarction and compared with urokinase. Fifty patients were given 6000 units of GE-0943 intracoronary and the totally occluded infarct-related arteries were recanalized in 92.0%. Fifty-four patients who were given 3000 units of GE-0943 intracoronary demonstrated a recanalization rate of 68.2%, while intracoronary administration of urokinase in 54 patients showed a recanalization rate of 70.4%. There was only one patient with hemorrhagic complication among GE-0943 3000-units group, none among GE-0943 6000-units group, and 5 among urokinase group. Thus, intracoronary administration of GE-0943 is very effective and safe with a dose up to 6000 units.

Adult↗
PubMed1989

Arterial-venous plasma concentration differences of 6-chloro-2-pyridylmethyl nitrate in humans after sublingual administration.

The plasma concentrations of 6-chloro-2-pyridylmethyl nitrate after sublingual administration were determined in six healthy male volunteers (venous plasma) and eleven patients (arterial plasma) with ischemic heart failure. The pharmacokinetics of the compound was investigated in volunteers. Plasma concentration-time data in each volunteer were found to fit a two-compartment open model with zero-order absorption. The pharmacokinetic parameters estimated from curve-fitting the plasma concentration-time data were as follow: Tmax 10 +/- 2.8 min, Cmax 8.16 +/- 2.48 ng/mL and CLP 6.16 +/- 1.79 L/min (means +/- S.D.). The arterial plasma concentrations (11.9 +/- 5.14 ng/mL) 7 min after sublingual administration were significantly higher (p less than 0.05) than those in venous samples (6.86 +/- 2.80 ng/mL). These results support that the arterial-venous gradient exists after administration of 6-chloro-2-pyridylmethyl nitrate in humans.

Administration, Sublingual↗
PubMed1989

[A case of spontaneous pneumothorax due to metastasis of urinary bladder carcinoma to the lung].

We reported a case of spontaneous pneumothorax associated with pulmonary metastasis of urinary bladder carcinoma. A 73-year-old male patient complaining of chest pain and dyspnea was admitted, who had undergone transurethral resection of the urinary bladder carcinoma and diagnosis of inactive pulmonary tuberculosis based on the chest X-ray film finding one year previously. On admission, chest X-ray film showed right pneumothorax, and the re-expanded chest X-ray film revealed a cystic lesion in the right upper lung field adjacent to the anterior chest wall, corresponding to the previous pulmonary lesion. Three months later, right thoracotomy was performed because of relapse accompanying by profuse air-leakage. There was a pleural fistula on the surface of the cystic lesion and necrotic tissue in it. Drainage bronchi were involved by surrounding tumorous tissue. Histological examination of the specimen from the cyst wall disclosed metastasis of transitional cell carcinoma of the bladder. The probable mechanism of the spontaneous pneumothorax probable consisted of stenosis of the right B3 bronchus caused by the metastatic tumor produced a check valve mechanism leading to cystic lesion, the rupture of which caused the spontaneous pneumothorax.

Aged↗
PubMed1989

[Two siblings of juvenile Parkinson's disease dystonic type (Yokochi type 3) and hereditary progressive dystonia with marked diurnal fluctuation (Segawa)].

Two siblings of juvenile parkinson's disease dystonic type (JPA Yokochi type 3) and hereditary progressive dystonia with marked diurnal fluctuation (Segawa, HPD) were reported. The family had consanguinity. The elder brother suffered from resting tremor of legs, left foot dystonia and left pes equinovarus at the age of 12 years and 5 months. At the age of 15, he developed tremor and rigidity of upper extremities. These symptoms did not show diurnal fluctuation and markedly responded to L-dopa treatment. He implicated wearing-off phenomenon at the age of 16, and on-off phenomenon and L-dopa-induced dyskinesia at the age of 18. He was diagnosed as JPA Yokochi type 3. The younger brother suffered from left pes equinovarus, right scoliosis and foot dystonia at the age of 8 years. These symptoms showed remarkable diurnal fluctuation, which ameliorated after sleep or rest and worsened afternoon. He noticed fine postural tremor of upper extremities at psychological tense state and right pes varus at the age of 16. He received L-dopa at the age of 17 and became to be remission. He was diagnosed as HPD. Since these two disorders related to basal ganglia show similar clinical symptoms mainly consisting of foot dystonia and similar clinicopharmacological response to L-dopa, it has been assumed that shared abnormalities in pathomechanism can exist between them. This study indicates that the same gene-regulated abnormality may participate in the development of these two disorders.

Child↗
PubMed1989

Altered responsiveness to sympathetic nerve stimulation and agonists of isolated left atria of diabetic rats: no evidence for involvement of hypothyroidism.

To clarify the role of hypothyroidism in diabetes-induced sympathetic neuropathy, we examined the responsiveness to sympathetic nerve stimulation and to agonists of the left atria of streptozotocin-induced diabetic rats, and compared it with those in hypothyroid, thyroxine(T4)-treated diabetic or T4-treated hypothyroid rats. Positive inotropic response of isolated left atria to transmural nerve stimulation (TNS) was examined in the presence of atropine. In diabetic rats, plasma triiodothyronine and T4 levels decreased markedly. The responses to TNS and norepinephrine (NE) also decreased. The decrease was greater in response to TNS, which may be due to the reduction of presynaptic NE release. As to the postsynaptic response, the maximal response to NE decreased without any significant change in ED50 value, and a similar decrease in the maximal response to Ca++ was also observed in spite of a slight decrease in the beta receptor density. Therefore, in diabetic rats the decreased response to TNS may result mainly from a decreased NE release from nerve endings and a decreased contractility beyond the adrenoceptor level. In hypothyroid rats, the response to TNS and NE decreased, and the decrease was again greater in response to TNS. The decrease in the NE response was due to the increased ED50 value without any change in the maximal response. Similarly, the maximal response to Ca++ did not change. Thus in the hypothyroid rats, the decreased response to TNS probably results from a decreased NE release from nerve endings as well as a decreased sensitivity to NE.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Potent antinociceptive effect of centrally administered delta-sleep-inducing peptide (DSIP).

The effect of central administration of delta-sleep-inducing peptide (DSIP) on nociceptive responses was evaluated in mice and rats. DSIP, administered intracerebroventricularly or intracisternally to mice, produced a significant dose-dependent antinociceptive effect in the tail-pinch and hot-plate tests. Intrathecal administration of DSIP did not produce such an effect. The antinociceptive effect of DSIP was blocked by pretreatment with the opioid antagonist, naloxone. Moreover, DSIP did not produce an antinociceptive effect in morphine-tolerant mice. Similar antinociceptive effects of DSIP were observed in rats. These results suggest that DSIP produces an antinociceptive effect by acting at the supraspinal level and that this effect is mediated via the opioid receptor, either directly or indirectly. DSIP may play an important role in pain regulation in the central nervous system.

Analgesics↗
PubMed1988

Trans-acting regulatory factors for T cell antigen receptor alpha- and gamma-chain gene expression.

BALB/c mouse thymoma-derived T cell line, CAK4.4 (Thy-1+, L3T4-, Lyt-2-), produced a large amount of TCR-gamma mRNA, a trace amount of TCR-beta mRNA but no detectable level of TCR-alpha mRNA. Another BALB/c mouse thymoma-derived T cell line, CAK1.3 (Thy-1+, L3T4+, Lyt-2+), synthesized a high level of TCR-alpha as well as TCR-beta mRNA but did not produce any amount of TCR-gamma mRNA. HAT-sensitive clones were established from the two T cell lines. Azaguanine-resistant, HPRT- CAK4.4 cells and bromodeoxyuridine-resistant, TK- CAK1.3 cells were fused by electrofusion method and the resultant hybrids were analyzed for expression of TCR genes as well as the changes of their cell surface phenotypes. Transcription of TCR-gamma gene was completely suppressed in all hybrids tested, although Southern blot analysis showed that the hybrids maintained TCR-gamma chain genes derived from both parental cells. TCR-alpha gene transcription occurred normally in one hybrid. In two other hybrids, TCR-alpha gene transcription was strongly suppressed. Treatment of the hybrid cells with 12-O-tetradecanoyl phorbol-13-acetate reversed the suppression of TCR-alpha gene transcription, but TCR-gamma gene transcription was not recovered by the same treatment. However, transcription level of TCR-beta gene was not changed in all hybrids. Our results suggested that the different trans-acting regulatory mechanisms control the transcription levels of TCR-alpha and TCR-gamma genes and that such a transcriptional control may play a crucial role in the determination of orderly appearance of TCR-gamma and TCR-alpha gene products during T cell ontogeny in the thymus.

Animals↗