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Biomedical subjects

K Nishimura

Publications and source records attributed to K Nishimura.

At least 415 records · Page 23Linked to original sources
PubMed1997

[A case report of one-stage repair for transposition of the great arteries with intact ventricular septum and coarctation of the aorta in neonate].

We report a neonatal case of one-stage repair for transposition of the great arteries with intact ventricular septum (TGA with IVS) and coarctation of the aorta (CoA). The surgery was performed at 27 days of age when the patient, a male, weighed 3408 g. Preoperative cardiac catheterization and angiography confirmed the diagnosis of TGA with IVS, CoA, atrial septal defect, patent ductus arteriosus, persistent left superior vena cava, left sided juxta-positioning of appendages and dextrocardia. The procedure was simultaneous subclavian flap aortoplasty through a left thoracotomy and an arterial switch operation through a median sternotomy. The patient's postoperative course was uneventful and he has grown well. Postoperative cardiac catheterization revealed mild pulmonary stenosis (pressure gradient of 19 mmHg between the right ventricle and the pulmonary artery) and mild aortic arch kinking from the arterial switch maneuver. One-stage repair, the combination of subclavian flap aortoplasty and arterial switch operation, provides a good clinical result in this complex malformation.

Abnormalities, Multiple↗
PubMed1996

Fas/APO-1-mediated apoptosis of human renal cell carcinoma.

We have investigated the Fas-mediated apoptosis of cultured human renal cell carcinoma OUR-10. OUR-10 cells express Fas antigen on their cell surface and showed apoptotic cell death by stimulation with anti-Fas agonistic antibody. Cell proliferation of OUR-10 was reduced to 62% by the addition of anti-Fas antibody. The cytotoxic effect of anti-Fas antibody on OUR-10 was augmented by the pretreatment of these cells with interferon-gamma, not with interferon-alpha or with interleukin-2. Flow cytometry demonstrated that preculture of Our-10 cells with interferon-gamma increased the cell surface Fas antigen. Immunohistochemical analysis of resected tissues from the patients with renal cancer revealed stronger expression of Fas antigen on the surface of cancer cells than that of normal cells. These data suggest that Fas may be one of the possible targets for a novel approach to human kidney cancer, and the efficiency of this Fas-mediated treatment for kidney cancer could be augmented by the treatment with interferon-gamma.

Apoptosis↗
PubMed1996

A second gene encoding a putative serine/threonine protein kinase which enhances spermine uptake in Saccharomyces cerevisiae.

We have isolated a new gene (PTK2) which restores spermine uptake of a polyamine uptake-deficient mutant of Saccharomyces cerevisiae (Kakinuma, Y., Maruyama, T., Nozaki, T., Wada, Y., Oshumi, Y., and Igarashi, K., 1995, Biochem, Biophys. Res. Commun. 216, 985-992). In magnesium-limited medium, the cell growth of a spermine-sensitive polyamine uptake mutant transformed with PTK2 recovered its sensitivity to spermine. The nucleotide sequence of the PTK2 gene indicated that it is identical with the YJR059W open reading frame of chromosome X encoding a putative serine/threonine protein kinase. The deduced amino acid sequence of the PTK2 gene product was 38% identical and 55% similar with that of the PTK1 (POT1) gene product, a putative serine/threonine protein kinase, which was found to enhance spermine uptake of the same mutant. The results indicate that polyamine transport of yeast is regulated by multiple phosphorylation/dephosphorylation pathways.

Amino Acid Sequence↗
PubMed1996

The importance of preserving disc structure in surgical approaches to lumbar disc herniation.

STUDY DESIGN: This study examined the clinical and radiographic results in patients with lumbar disc herniation treated surgically with one of four procedures: two different methods of herniotomy using a posterior approach and two different methods of percutaneous nucleotomy. OBJECTIVES: The authors goal was to identify the structural changes in the disc after each of the procedures and to correlate them with the clinical outcome. SUMMARY OF BACKGROUND DATA: The details of herniotomy procedure via a posterior approach or by percutaneous nucleotomy as described by many authors have not been consistent. Furthermore, previous reviews of these studies have been less than satisfactory. METHODS: One hundred fifty-seven herniotomies using a posterior approach and 94 percutaneous nucleotomies were studied with a follow-up of at least 2 years. Each of these groups was divided into two subgroups to evaluate the role of the remaining nucleus pulposus in the central area of the disc. RESULTS: Changes seen in imaging studies, such as a decrease in disc height and an increase of intervertebral instability in plain radiographs and a decrease in signal intensity of the disc in magnetic resonance images, were significantly less common in the subgroups of herniotomy and percutaneous nucleotomy in which the nucleus pulposus in the central area of the disc was preserved when compared with the subgroups in which a complete removal of the disc was attempted. The changes seen in the imaging studies were significant in patients younger than 40 years of age and correlated closely with the clinical results. CONCLUSIONS: Preserving the nucleus pulposus during the surgical treatment of lumbar disc herniation in patients younger than 40 years of age resulted in better radiographic and clinical results.

Adolescent↗
PubMed1996

Continuous monitoring of short-latency somatosensory evoked potentials during cardiac and aortic surgery.

The effectiveness of monitoring somatosensory evoked potentials (SEPs) intraoperatively to detect brain damage early remains controversial. To assess the diagnostic accuracy of this modality, a study was conducted between 1991 and 1994, recording SEPs in 287 consecutive patients undergoing cardiac and aortic surgery using cardiopulmonary bypass (CPB) with moderate hypothermia or deep hypothermic circulatory arrest. From P1 to N2 of the SEPs occurring within 50 ms latency in response to electrical stimulation of the median nerve were recorded over the contralateral postcentral cortex at 5-min intervals using a Neuropack-2 (Nihon Koden, Tokyo, Japan). Normal SEPs were recovered in 247 patients postoperatively; however, 2 of these patients had suffered a cerebral infarction and 1, a transient stroke intraoperatively, demonstrating a false-negative incidence of 1.2%. On the other hand, three different types of abnormal SEPs were recorded postoperatively. P1 and N1 absence, probably caused by a subcortical lesion, was observed in 4 patients; P2 and N2 absence, probably caused by a cortical lesion, was observed in 8 patients; and a flat SEP, representing diffuse damage, was observed in 2 patients. Among these 14 patients with abnormal SEPs, 7 showed no neurologic disturbance at all, demonstrating a false-positive incidence of 50%. Thus, we concluded that when normal SEPs are recovered during weaning from CPB, the incidence of brain damage could be predicted at below 5%. Conversely, when abnormal SEPs are demonstrated, the incidence of brain dysfunction impeding a return to active life is estimated to be about 70%.

Adolescent↗
PubMed1996

A new type of growth exhibited by Trimmatostroma abietis.

Trimmatostroma abietis initially grew as hyphae when grown in various media containing yeast extract or bactopeptone. It grew as segmented elements (lumbricoid elements) characterized by bidirectional growth, when grown in Czapek-Dox broth or yeast nitrogen base supplemented with 1% glucose. A lumbricoid element usually was 10-70 microns in length, with transverse septation only and contained 3 to 15 cells. Growth and propagation, as revealed by time-lapse photomicrography occurred as follows. Elements usually grew by apical elongation without widening; after simple apical elongation adjacent parts of two central cells eventually started to grow, resulting in the separation of the element into two.

Microscopy, Electron↗
PubMed1996

Phylogeny of Epidermophyton floccosum and other dermatophytes.

Eleven strains of Epidermophyton floccosum were compared with 5 Microsporum and 5 Trichophyton species with respect to the restriction fragment length polymorphism (RFLP) of the mitochondrial DNA to reveal their phylogenetic relationships. The phylogeny of 11 species showed that the three dermatophyte genera could not be separated from each other and could be considered to be congeneric. This result is not inconsistent with the results from ribosomal RNA sequences.

DNA, Fungal↗
PubMed1996

Management of subarachnoid fluid collection in infants based on a long-term follow-up study.

We report the natural history and management of subarachnoid fluid collections in infants and their management based on a longterm follow-up study in 20 cases. These subarachnoid fluid collections were resolved spontaneously in 17 of 20 patients and only 3 by surgical intervention at the age of 2. In our 20 patients the natural history of subarachnoid fluid collection in infants was benign unless the patients sustained head trauma. Surgical treatment was performed in the cases where a subarachnoid fluid collection developed into a subdural haematoma. Head trauma may precipitate subdural haematoma in patients with subarachnoid fluid collection. All patients except one who underwent the placement of subdural-peritoneal shunt, attained normal psychomotor development in time. During the follow-up period of 3 to 10 years after resolution of the fluid collection, no patient has had a recurrence once it resolved.

Cerebrospinal Fluid Shunts↗
PubMed1996

99mTc-MIBI accumulation in the parathyroid autograft in a patient with recurrent hyperparathyroidism.

A case with recurrent hyperparathyroidism secondary to chronic renal insufficiency is reported. The patient had undergone total parathyroidectomy and autotransplantation of parathyroid tissue five years ago. Bone scintigraphy clearly demonstrated skeletal involvement of secondary hyperparathyroidism and 99mTc-methoxyisobutylisonitrile scintigraphy clearly demonstrated a hyperfunctioning parathyroid autograft.

Bone and Bones↗
PubMed1996

Effect of the insect growth regulators, N-tert-butyl-N, N'-dibenzoylhydrazines, on neural activity of the American cockroach.

N-tert-Butyl-N,N'-dibenzoylhydrazines, agonists of 20-hydroxyecdysone, decelerated the rising and falling phases of an action potential, which had been electrically induced in the cockroach giant axon, at moderately high concentrations. 4-Aminopyridine, a blocker of potassium channels of nerve, selectively decelerated the falling phase of the action potential. This class of compounds caused convulsions in American cockroaches when injected. The convulsive activity seemed to be positively related to the activity to decelerate the falling phase of the action potential.

4-Aminopyridine↗
PubMed1996

Analysis of right ventricular function during bypass of the left side of the heart by afterload alterations in both normal and failing hearts.

This study investigated the mechanism of right ventricular failure during bypass of the left side of the heart by precisely assessing right ventricular function with use of a conductance catheter. Bypass of the left side of the heart was established with a centrifugal pump in 10 mongrel dogs weighing 11 to 19 kg. Right ventricular function during left heart bypass was evaluated by two parameters that were both derived from measurement of relative change in right ventricular volume by the conductance catheter technique. One parameter was the right ventricular end-systolic pressure-volume relationship as a load-independent index, and the other was the peak right ventricular pressure-right ventricular stroke volume relationship as a "force-velocity relationship." These parameters were measured in both normal and failing hearts while afterload was increased by bilateral intrapulmonary balloon inflation. Moreover, changes in these relationships were observed by varying assist ratios of left heart bypass from 0% to 100%. Failing heart models were induced by normothermic aortic clamping for 20 minutes. The right ventricular end-systolic pressure-volume relationship in normal hearts did not change, irrespective of the assist ratio of left heart bypass, whereas that in failing hearts decreased from 4.25 +/- 1.41 mm Hg/ml without bypass of the left side of the heart to 3.53 +/- 1.30 mm Hg/ml after 100% assist of left heart bypass (p < 0.05). In the peak right ventricular pressure-right ventricular stroke volume relationship, right ventricular stroke volume was almost constant in normal hearts when afterload was increased regardless of the assist ratio of left heart bypass. Moreover, right ventricular stroke volume was maintained at a higher level during bypass of the left side of the heart compared with that without left heart bypass. However, that slope of the relationship in failing hearts was inversely linear and became significantly steeper after 100% assist of bypass of the left side of the heart compared with that without left heart bypass (-0.131 +/- 0.042 versus -0.051 +/- 0.038, p < 0.005). Therefore ++these two slopes of the relationship intersected at a point that was considered the critical point of afterload during bypass of the left side of the heart. In other words, right ventricular stroke volume was decreased by 100% left heart bypass above the critical point of afterload. In conclusion, this study demonstrates not only that bypass of the left side of the heart results in an increase in right ventricular stroke volume in both normal and failing hearts at the physiologic range of afterload, but also that right ventricular function against higher afterload is impaired by 100% assist of bypass of the left side of the heart in failing hearts.

Animals↗
PubMed1996

Influence of baseline airway calibre and pulmonary emphysema on bronchial responsiveness in patients with chronic obstructive pulmonary disease.

STUDY OBJECTIVE: Bronchial hyper-responsiveness (BHR) is widely observed in patients with chronic obstructive pulmonary disease (COPD). However, its clinical significance in COPD has not yet been established. To determine the factors that influence BHR in COPD, multiple linear regression analysis was used to analyse the relationship between BHR to methacholine and baseline forced expiratory volume in 1 s (FEV1), vital capacity (VC), residual volume (RV)/total lung capacity (TLC), static compliance (Cst), transfer coefficient of the lung (Kco), and the percentage of low attenuation area (%LAA) determined by computed tomographic (CT) scan. METHODS: Bronchial responsiveness to methacholine was determined in 63 patients with COPD by the dosimeter method and expressed as PD20FEV1. Residual volume and TLC were determined by body plethysmography. The percentage of low attenuation area was defined as the percentage of area less than -960 Hounsfield unit on a CT scan of the thorax. RESULTS: Forced expiratory volume in 1s (%predicted) and %LAA correlated with BHR (P = 0.023 and 0.020, respectively), while VC (%pred), RV/TLC, Cst and Kco did not. The coefficient of determination was 0.43. The regression analysis showed that a 10% increase in FEV1 (%pred) and a 10% decrease in %LAA would increase log(PD20FEV1) by 0.145 and 0.117, respectively. CONCLUSIONS: A considerable proportion of the BHR in COPD is related to functional abnormalities and morphologic changes of emphysema, such as decreased baseline airway calibre and destruction of the lung parenchyma.

Aged↗
PubMed1996

Dysfunction of cholinergic and dopaminergic neuronal systems in beta-amyloid protein--infused rats.

Accumulations of beta-amyloid protein are characteristic and diagnostic features of the brain of Alzheimer's disease patients; however, the physiological role of this protein in CNS is unknown. We have previously reported that continuous infusion of beta-amyloid protein into rat cerebral ventricle impairs learning ability and decreases choline acetyltransferase activity, a marker enzyme of cholinergic neuron. In this study, the effects of beta-amyloid protein infusion on the release of neurotransmitters in cholinergic and dopaminergic neuronal systems were investigated by using an in vivo brain microdialysis method. Nicotine-stimulated release of acetylcholine and dopamine in these animals was significantly lower than that in vehicle-infused rats. Further, dopamine release induced by high-K stimulation was decreased in beta-amyloid protein-infused rats compared with vehicle-infused rats. These results suggest that the release of the two transmitters, acetylcholine and dopamine, was decreased by beta-amyloid protein and that learning deficits observed in the beta-amyloid protein-infused rats are partly due to the impairment of neurotransmitter release. Furthermore, continuous infusion of beta-amyloid protein may be a useful method to produce the animal model of Alzheimer's disease.

Acetylcholine↗