Search PubMed⌕ Search

Biomedical subjects

H Asano

Publications and source records attributed to H Asano.

At least 91 records · Page 5Linked to original sources
PubMed1996

A newly-designed shape-memory coil stent for esophageal stricture: a preliminary report.

A newly designed coil esophageal endoprosthesis was developed using a thermal shape-memory titanium-nickel alloy. The major advantages of this stent lie in (a) its small diameter while in its compressed state in ice water and (b) the large lumen which is achieved once it has been warmed to body temperature. The technical feasibility and tissue compatibility of this stent were tested on four beagle dogs: two with an anastomotic stricture and two with a stenosis induced by the injection of monoethanolamine oleate. The teflon-coated stent was inserted under fluoroscopy and removed 4 weeks after implantation. No signs of esophageal reobstruction were observed in any of the animals after implantation or extraction of the stent, although the dog which had received the first stent without teflon coating developed obstruction caused by granulation tissue. Our preliminary experience strongly suggests that the shape-memory alloy stent with teflon coating may be used in the endoscopic treatment of anastomotic stenosis after esophagectomy, as well as of esophageal obstruction caused by carcinoma.

Alloys↗
PubMed1996

Regional blood flow and the endocrine response to sustained hypoxemia in the preterm ovine fetus.

To determine the circulatory response of the preterm fetus to a sustained hypoxic insult, regional blood flow was measured (microsphere technique) in 12 unanesthetized fetal sheep (0.75 gestation) during a normoxic control period, after 1 h and 8 h of sustained hypoxemia, and after a 1-h recovery period. Associated endocrine changes which might relate to organ-specific changes in blood flow were also assessed. Myocardial and cerebral blood flow were increased by 240 and 90%, respectively, such that oxygen delivery to the heart was well maintained throughout the study, whereas that to the brain was significantly decreased by 8 h of hypoxic study. Regional blood flows for all structures within the brain showed similar percent increases, except that for the pituitary gland, where the increase was much smaller, and that for the choroid plexus, where blood flow actually fell. Whereas blood flow to upper body muscle showed no significant change throughout the study, that to the thyroid was increased by 70% by 1 h of hypoxic study but fell thereafter. Adrenal cortical blood flow relative to that of the medulla was increased 3-fold by 8 h of hypoxic study, indicating a differential effect of sustained hypoxia on these vascular beds. Although pituitary and thyroid blood flows showed no relationship to respective trophic and/or secretory hormones measured, values for adrenal cortical flow relative to medullary flow were well correlated with plasma concentrations of ACTH. It is concluded that the "centralization" of blood flow to vital organs in response to a sustained hypoxic insult is qualitatively similar for both the preterm and near term ovine fetus and that hypoxic regulatory mechanisms may be better protective of the heart. Additionally, a role for the functional activation of the adrenal gland in its blood flow response to sustained hypoxemia is suggested.

Acidosis↗
PubMed1996

[The perinatal risk factors and periventricular leukomalacia (PVL) in premature infants--relationship between fetal heart rate decelerations and PVL].

Periventricular leukomalacia (PVL) has recently been recognized as an important risk factor of neurological impairment in premature infants. We studied 29 PVL cases on perinatal risk factors comparing with a non-PVL matched control group retrospectively. Variable decelerations were more frequently observed with statistical significance in the PVL group in the intrapartum period. Then another study was conducted to evaluate the relationship between fetal heart rate (FHR) decelerations and cystic PVL prospectively. Since January 1993 through December 1994 we studied 209 low birth weight infants (31.1 +/- 3.2 weeks, 1,424 +/- 419 g) who had been subjected to intrapartum FHR monitoring and postnatal sonographic intracranial examinations sequentially every 7 days until discharge. Cystic PVL was detected in 6 of 209 cases (2.9%) and occurred only in infants who had revealed severe variable deceleration or prolonged deceleration (6/37, 16%) in intrapartum FHR monitoring. We conclude that in low birth weight infants intrapartum severe variable deceleration or prolonged deceleration might play a causal role in cystic PVL.

Bradycardia↗
PubMed1996

[Influence of hyperkalemia on clinical decision making].

INTRODUCTION: In our hospital, extreme values are promptly reported in routine test, one of three kinds of reporting system. We investigated the influence of hyperkalemia on clinical decision making and discussed critical levels of hyperkalemia and the significance of prompt report of it. MATERIALS AND METHODS: One hundred eighty six patients with more than 6 mmol/l of blood potassium detected during 1993 were studied. Each episode in a patient with different causes was classified as a separated case and finally 194 cases were studied. Cause of hyperkalemia, clinical symptoms, electrocardiogram, outcome and treatment were investigated. RESULTS AND DISCUSSION: The mortality was 14% in 6 approximately 7 mmol/l, 42% in 7 approximately 8 mmol/l and 100% in more than 8 mmol/l. Electrocardiograms showed high peaked T wave in 6 approximately 7 mmol/l, widening of QRS complex and bradycardia in 7 approximately 8 mmol/l, and ventricular fibrillation and flatter in more than 8 mmol/1. These results supported that 7 mmol/l was acceptable as a critical value. One hundred percent of outpatients and 79% of inpatients undergoing emergency tests were promptly treated by doctors, and 61% and 35% undergoing urgent tests, and 52% and 30% undergoing routine tests (prompt report) were done respectively. Prompt reports of extreme values were more useful in decision making for outpatients than inpatients. Urea-N was more important than potassium as a factor influencing decision making in both patients, because most patients had renal failure or heart failure. CONCLUSION: The mortality and electrocardiogram studies supported that 7 mmol/l was an acceptable critical value. Prompt reports of hyperkalemia were more significant to clinical decision making for medical care for outpatients than for inpatients.

Clinical Laboratory Techniques↗
PubMed1995

Lung metastasis from parathyroid carcinoma causing recurrent renal hyperparathyroidism in a hemodialysis patient: report of a case.

We report herein the case of a 46-year-old woman on hemodialysis (HD) who developed recurrent renal hyperparathyroidism induced by lung metastasis from parathyroid carcinoma. The patient had been commenced on HD for chronic renal failure about 20 years earlier and had undergone a parathyroidectomy for advanced renal hyperparathyroidism 8 years later. After the initial operation, further explorations of the neck were performed due to recurrence, despite which the hyperparathyroidism persisted and she was finally referred to our department. The appearance of multiple coinlike lesions on a chest X-ray and computed tomography led to the diagnosis of recurrent hyperparathyroidism induced by lung metastasis from parathyroid carcinoma. A pulmonary wedge resection was performed and the metastatic parathyroid nodules were removed. Of the several hypotheses about the etiology of parathyroid carcinoma in HD patients, it is most likely that the parathyroid hyperplasia induced by chronic renal failure develops into carcinoma. Even in renal hyperparathyroidism, we should bear in mind the possibility that metastatic parathyroid carcinoma is a possible source of excess parathyroid hormone secretion at recurrence.

Carcinoma↗
PubMed1995

Prenatal infection with Setaria marshalli (Boulenger 1921) in cattle.

A full year's epidemiological study was conducted in Japan on prenatal infection with Setaria marshalli in cattle. A total of 65 bovine fetuses of abattoir origin, both male and female of 2-9 months of age, were examined postmortem. Results showed that S. marshalli adult worms were detected in the peritoneal cavity of six bovine fetuses of 7-9 months of age during the months of October-December, but not in fetuses of any age during the months of January-September. Infection was not detected in any fetuses under the age of 7 months at any given month of the year. This is the first observation to demonstrate prenatal S. marshalli infection in fetuses. Since S. marshalli has not been detected in cattle older than 2 years, it is speculated that prenatal infection is the common type, while postnatal infection is rather uncommon. Considering fetal age and the seasonal factor, a fetus of age 4-5 months would most frequently develop prenatal infection in the June-August period, when mosquitoes are active as vectors. It is concluded, therefore, that S. marshalli prenatal infection develops during the middle stage of fetal life in summer.

Animals↗
PubMed1995

Active life expectancy among elderly Japanese.

BACKGROUND: This study estimated the active life expectancy (ALE) among the elderly in a Japanese urban society to determine whether or not the Japanese live long lives at the expense of life quality. METHODS: Survival and ability to perform activities of daily living (ADLs) were followed up on a probability sample (n = 3,459) of the aged people living in Sendai City, Japan, between 1988 and 1991. ALE was calculated by an increment-decrement life table method. RESULTS: At age 65, ALE was 14.7 years for men and 17.7 years for women. The duration of active life occupied 91% of the total life expectancy for men and 87% for women. These values were further compared with those reported for the elderly in the United States. ALE among the Japanese subjects was longer than that among the American elderly. The percentage of remaining life that was active was comparable with that in the United States. However, the interpretation of the results requires caution because of the difficulty in comparing self-reported disabilities across cultures. CONCLUSION: The authors conclude that it is premature at this time to judge which country is better in terms of functional status among the elderly. An international comparison of ALE would create an opportunity to evaluate and promote health and function of the elderly population worldwide. For this purpose, an international standardization of ALE measurement is urgently needed.

Activities of Daily Living↗
PubMed1995

OP-1206, a prostaglandin E1 derivative, attenuates the thermal hyperesthesia induced by constriction injury to the sciatic nerve in the rat.

Nerve ischemia induces wallerian degeneration and peripheral neuropathy, the nerve constriction injury induces thermal hyperesthesia. Nerve ischemia is one possible mechanism in the development of thermal hyperesthesia in the nerve constriction injury model. Prostaglandin E1 increases tissue blood flow. In the present study, the authors examine the role of nerve ischemia in the maintenance of the thermal hyperesthesia induced by nerve constriction injury by orally administering OP-1206, a prostaglandin E1 derivative. A nerve constriction injury model was created by making four loose ligations around the rat sciatic nerve, which induces thermal hyperesthesia in the ligated paw in 2-5 days. OP-1206, was administered six times (Day 7, one time; Day 8, two times; Day 9, two times; Day 10, one time). A single administration of OP-1206 had no effect on the thermal hyperesthesia. Six hours after the sixth-administration of OP-1206, the level of the thermal hyperesthesia was attenuated in a dose-dependent manner, and this effect lasted more than 1 day after the last drug administration. These data indicate that nerve ischemia plays an important role in maintaining the thermal hyperesthesia induced by nerve constriction injury in the rat.

Alprostadil↗
PubMed1995

Management of meconium aspiration syndrome by tracheobronchial lavage and replacement of Surfactant-TA.

Meconium aspiration syndrome creates mechanical airway obstruction with air trapping and atelectasis. Tracheobronchial saline lavage to dislodge meconium may precipitate respiratory distress, a wet lung appearance and respiratory failure. Two case studies are reported in which meconium aspiration resulted in mechanical obstruction and displacement of surfactant and in whom tracheobronchial saline lavage and artificial surfactant replacement reversed respiratory failure.

Female↗
PubMed1995

Physical status and dementia risk: a three-year prospective study in urban Japan.

A three-year prospective study of 3,180 non-dementia persons in Sendai City, Japan was conducted to examine the effects of physical status and diseases diagnosed on dementia incidence. This cohort had been made at the initial survey in 1988 and the evaluation for incident dementia was performed on 2,461 respondents (77.4%) in a follow-up survey in 1991. Regarding physical status, the logistic regression including sex, age, health status, ambulatory activity and activities of daily living indicated that the poor health status and the limitation of ambulatory activity were significantly associated with an increased risk of dementia. The significant positive association with dementia was observed on stroke, respiratory disease and depression. This study identified the high risk population for dementia in the aspect of physical status.

Activities of Daily Living↗
PubMed1995

Dementia and physical disability as competing risks for mortality in a community-based sample of the elderly Japanese.

To examine whether an excess mortality due to dementia is independent of coexisting physical disability, a probability-sample of the non-institutionalized elderly (n = 3,308) living in Sendai City, Japan was followed between 1988 and 1991. Of those, 128 were diagnosed as dementia in 1988 by psychiatrists, using Diagnostic and Statistical Manual of Mental Disorders, Third Edition-Revised as a diagnostic standard. Information on the ability to perform activities of daily living (ADL) was collected by self-report of the study subjects in 1988 baseline survey. The survival status was investigated three years later. The risks of dementia and co-existing ADL disability for mortality was examined by Cox proportional hazard models. The results indicated that the relation between dementia and mortality was two-fold, depending upon the physical functions. Dementia increased the risk for mortality among those without ADL disability, but it did not so among those with ADL disability, rather ADL function was a stronger predictor for mortality among the latter individuals. Prevention and treatment of physical disability would be important for improving the survival of the demented people.

Aged↗
PubMed1995

Herbimycin A inhibits phorbol ester-induced morphologic changes, adhesion, and megakaryocytic differentiation of the leukemia cell line, MEG-01.

12-O-Tetradecanoylphorbol 13-acetate (TPA) induces rapid changes in the morphology of the human megakaryoblastic leukemia cell line, MEG-01, as well as changes in adhesion and megakaryocytic differentiation. To investigate the signal transduction pathway of these three phenomena, we studied the effect of herbimycin A, an inhibitor of tyrosine kinase (TK) and the effects of calphostin C, a specific inhibitor protein kinase C (PKC) on TPA treated MEG-01 cells. Both herbimycin A and calphostin C inhibited all three TPA-induced phenomena, suggesting that both pathways are required for these phenomena. Herbimycin A but not calphostin C blocked the tyrosine phosphorylation of cellular proteins. Immunohistochemical staining of PKC using an anti-PKC monoclonal antibody showed that herbimycin A did not interfere with the translocation and subsequent down regulation of PKC induced by TPA, suggesting that the TPA-induced effect on PKC (translocation and probably its activation) is not dependent on TK. Induction of c-fos and c-jun expression by TPA was inhibited by both herbimycin A and calphostin C, suggesting that both PKC and TK pathways are necessary for the induction of the TPA-induced transcription factor AP1, which is a known TPA-inducible early immediate gene product. Taken together, our results show that the tyrosine kinase signal transduction system as well as the PKC pathway is indispensable for the TPA-induced phenomena of morphologic change, cell attachment, early immediate gene expression, and lineage-specific phenotypic expression in the MEG-01 cell line.

Benzoquinones↗
PubMed1995

[Clinical result of left ventricular free wall rupture resulting from acute myocardial infarction].

We have treated 10 patients of left ventricular free wall rupture (LVFWR) resulting from acute myocardial infarction (AMI) in our intensive care unit (ICU) from Oct. 1984 to Dec. 1993. Nine of 10 patients underwent surgical repair, however, one patient was treated with pericardocentetesis in ICU and fibrin-glue was infused into the pericardial space (fibrin-glue therapy:FG therapy). The survival rate of surgical repair was only 33% (3/9), especially that was only 17% (1/6) when cardiopulmonary bypass (CPB) was required. One patient (49-year-old, male) suffered from cardiogenic shock following AMI in the posterior wall was performed coronary angioplasty (PTCA) in emergency and IABP support was required. Fourth day after PTCA, a sudden hemodynamical collapse had occurred on this patient due to cardiac tamponade. This patient was treated with pericardiocentetesis in ICU and FG therapy was performed, because all surgical teams were occupied in their operations. After FG therapy hemodynamical stability was obtained, the patient was survived and discharged at 2 months after LVFWR. In conclusion, the surgical result of LVFWR is still not good, especially when CPB was utilized. FG therapy was successful in one patient, suggesting FG therapy can be an alternative therapy for LVFWR when surgical team is not available.

Aged↗
PubMed1995

[The perinatal risk factors of periventricular leukomalacia (PVL) in premature infants].

Periventricular leukomalacia (PVL) has recently been recognized as an important risk factor in neurological impairment of the premature infant. We studied 29 PVL cases concerning perinatal risk factors retrospectively comparing them with a non-PVL matched control group. Variable decelerations were more frequently observed with statistical significance in the PVL group in the intrapartum period. There was no significant difference between the two groups in the appearance of late deceleration. A lower incidence of RDS, a higher incidence of low Apgar score, a longer period of ventilation and oxygen inhalation and a more persistent presence of apneic spells were documented in the PVL group with statistical significance. Our study suggests the significance of variable deceleration as a risk factor in the occurrence of PVL in premature infants as well as other previously documented risk factors.

Apgar Score↗
PubMed1994

Evidence for nonclonal hematopoietic progenitor cell populations in bone marrow of patients with myelodysplastic syndromes.

Clonality of marrow hematopoietic progenitor cells in myelodysplastic syndromes (MDS) was analyzed by X-chromosome inactivation pattern using polymerase chain reaction (PCR). Five female patients were included in this study; two with refractory anemia (RA) and three with RA with excess blasts (RAEB). They were heterozygous for BstXI restriction fragment length polymorphisms (RFLP) of the X-chromosome-linked phosphoglycerate kinase (PGK) gene. In each patient, erythroid and nonerythroid colonies, grown in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF), exhibited no remarkable difference in clonal constitution. Two patients showed only one methylation pattern, suggesting the monoclonal origin of hematopoietic progenitor cells. Colonies of two other patients exhibited predominant and minor methylation patterns in PGK gene, indicating that nonclonal progenitor cells remain a minor population. The bone marrow of one patient appeared to contain a greater proportion of nonclonal progenitors. Stem cell factor (SCF), a potent colony-stimulating factor, enhanced both erythroid and nonerythroid colony formation. However, it did not notably alter the clonal constitutions. We conclude that nonclonal hematopoietic progenitor cells can persist in a substantial number of MDS patients.

Aged↗
PubMed1994

Cerebral metabolism during sustained hypoxemia in preterm fetal sheep.

OBJECTIVE: The purpose of this study was to determine the effect of sustained hypoxia with resulting metabolic acidosis on cerebral metabolism in the preterm ovine fetus. STUDY DESIGN: Twelve fetal sheep were studied at 0.75 of gestation during a normoxic control period, after 1 and 8 hours of sustained hypoxemia, and again after a 1-hour recovery period. Cerebral arteriovenous differences were analyzed for oxygen content, blood gases and pH, glucose, and lactate. Cerebral blood flow was measured with the microsphere technique. RESULTS: Induced hypoxemia resulted in a variable degree of fetal acidemia that was entirely metabolic. Although cerebral oxidative metabolism was well maintained throughout the study, cerebral glucose consumption was variably increased when measured after 1 hour of sustained hypoxemia, with a subsequent decrease after 1 hour of recovery. Although lactate was neither consumed nor produced during the control period, by 8 hours of hypoxic study a significant efflux of lactate from the brain was evident, which continued into the recovery period. CONCLUSION: Sustained hypoxemia results in an increase in the anaerobic metabolism of glucose by the preterm fetal brain independent of any change in cerebral oxidative metabolism, which may give rise to an accumulation of lactic acid and contribute to neurologic impairment.

Animals↗
PubMed1994

Time-dependent effect of morphine and time-independent effect of MK-801, an NMDA antagonist, on the thermal hyperesthesia induced by unilateral constriction injury to the sciatic nerve in the rat.

BACKGROUND: It is known that peripheral nerve injury induces time-dependent changes in dorsal horn function. The current study investigated the time dependency of the effects of intrathecal morphine and MK-801, an N-methyl-D-aspartate antagonist, on the thermal hyperesthesia evoked by unilateral constriction injury to the sciatic nerve in the rat. METHODS: In rats with a unilateral constriction injury to the sciatic nerve, paw withdrawal latency against thermal stimulation for the injured paw was typically 3 s less than that for the uninjured paw during the first 5 weeks after the injury. Drugs were administered intrathecally 1 or 5 weeks after the nerve injury. RESULTS: Intrathecal morphine increased the paw withdrawal latencies of both the injured paw and the uninjured paw in an equally dose dependent manner in the 1-week study. In the 5-week study, morphine increased the paw withdrawal latency of the uninjured paw in a dose-dependent manner, but not that of the injured paw. Intrathecal MK-801 increased the paw withdrawal latency of the injured paw to the level of the uninjured paw in a dose-dependent manner in both the 1- and 5-week studies. CONCLUSIONS: These data indicate that (1) an N-methyl-D-aspartate receptor-mediated spinal facilitation may be the common mechanism maintaining the thermal hyperesthesia evoked by the constriction injury, and (2) the effects of intrathecal morphine on this thermal hyperesthesia are time-dependent.

Animals↗