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Biomedical subjects

K Nishimura

Publications and source records attributed to K Nishimura.

At least 1,351 records · Page 75Linked to original sources
PubMedDate not supplied

Ruptured aneurysm of the right sinus of Valsalva: two pulsed Doppler echocardiographic studies.

Pulsed Doppler echocardiography (PDE) was performed on two cases with ruptured aneurysm of the right sinus of Valsalva into the right ventricle. PDE revealed a wide band pattern throughout the cardiac cycle when the sample volume was placed within the aneurysm. In the right ventricle below the aneurysm, a continuous disturbed flow in case 1 and a diastolic turbulence in case 2, was widely recorded, respectively. In contrast, the flow pattern of the right ventricular outflow tract distal to the aneurysm showed a systolic disturbed flow in both cases. These PDE findings were consistent with the shunt flows in angiocardiography.

Adult↗
PubMedDate not supplied

Relationship between regional myocardial blood flow and mitochondrial function.

The purpose of this study was to clarify the relationship between myocardial mitochondrial dysfunction and the degree plus duration of restricted coronary blood flow. 135 anesthetized and open-chest dogs were divided into 3 groups according to coronary occlusion time: 10, 20, and 60 min. Regional myocardial blood flow (MBF) was determined in both ischemic and nonischemic areas before and during coronary occlusion using the hydrogen gas clearance method. Myocardial mitochondria were prepared from each area in which MBF was determined after 10, 20, or 60 min of coronary ligation, and their respiratory control index (RCI), ADP/O, and rate of oxygen consumption in state III O2 (St. III O2) were measured. The MBF measured in 135 dogs before coronary ligation was 103 +/- 25 ml/min/100 g (mean +/- SD) for the area to be rendered ischemic and 101 +/- 24 ml/min/100 g for the control area. The MBF in the ischemic area did not cease completely following coronary ligation, and the distribution of MBF showed variations which seemed attributable to individual differences. In the 10-min group, no index of mitochondrial function of the ischemic area differed from that of the nonischemic area at any level of MBF. When MBF was less than 20 ml/min/100 g, RCI of mitochondria from the ischemic area was significantly lower than that from the nonischemic area, in the 20- and 60-min groups. When MBF was less than 20 ml/min/100 g, St. III O2 of mitochondria from the ischemic area significantly decreased compared with that from the nonischemic area, in the 20-min group. In the 60-min group, MBF less than 30 ml/min/100 g, St. III O2 of mitochondria from the ischemic area was likewise significantly decreased. Moreover, with MBF below 20 ml/min/100 g, both RCI and St. III O2 of mitochondria from the ischemic area were significantly lower in the 60-min group than in the 20-min group. These results indicate that ischemia-induced mitochondrial dysfunction depends on the degree of decrease in the blood flow of the area involved as well as on the duration of ischemia, and the blood flow that is critical for survival, based on mitochondrial function, is approximately 20 ml/min/100 g, i.e., a reduction to 20% of normal value.

Animals↗
PubMedDate not supplied

CT imaging of biliary enteric fistula.

BACKGROUND: To define the signs useful for differentiating between gallbladder-enteric fistula (GB-EF) and common bile duct-enteric fistula (CBD-EF) on computed tomography (CT) because the prognosis and management of the two are different. METHODS: CT scans in 13 patients with pneumobilia, who had not had surgical biliary-enteric anastomosis and endoscopic sphincterotomy, were reviewed. The presence of fistula itself, the location of air in the biliary system, and the appearance of the gallbladder were assessed. RESULTS: The causes of pneumobilia were GB-EF in seven patients, CBD-EF in three patients, emphysematous cholecystitis (EC) in one patient, gallbladder cancer (GBC) in one patient, and incompetent sphincter of Oddi in one patient. In three of seven GB-EF patients (43%) and in none of the three CBD-EF patients (0%), the fistula itself was detected. Air was detected in the common bile duct in four of seven GB-EF (57%) and in all three CBD-EF (100%) patients, and GBC. In six of seven GB-EF (86%) and in one of three CBD-EF (33%) patients, the gallbladder was contracted. Thus, the location of air and the contraction of gallbladder were useful signs to differentiate GB-EF from CBD-EF. CONCLUSION: CT can distinguish between GB-EF and CBD-EF.

Aged↗
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Temporal modulation transfer function in normal-tension glaucoma patients.

A new screening test involving the Flicker System was used to measure temporal modulation transfer function in an effort to detect early-stage glaucoma. The study involved 64 normal-tension glaucomatous eyes and 65 normal control eyes. Patients with early-stage glaucoma (stage 0-1 of the Aulhorn-Greve classification) showed a significant modulation decrease in the 20-45 Hz range, compared to the modulation in normal eyes (P < 0.05). Patients with moderate stage glaucoma (stage 2-3) also exhibited significantly decreased modulation values in the 14-55 Hz range. In the 25-45 Hz range, the reduction of modulation in patients with diffuse visual defect was more profound than in those with localized or mixed defects. The results of the present study suggest the presence of diffuse visual function deficit in glaucoma.

Adult↗
PubMedDate not supplied

Magnetic resonance imaging around the eustachian tube.

Magnetic resonance imaging (MRI) of the eustachian tube, the nasopharynx, and the middle ear was performed in normal subjects and patients with ear diseases. In normal subjects, the high soft tissue contrast resolution of MRI gave a clearer view of nasopharyngeal structures compared to roentgenologic examinations including computed tomography (CT). Several cases of nasopharyngeal pathology are also presented. Nasopharyngeal carcinoma was excellently depicted, and its margin was clearly visualized. Tumor involvement of the eustachian tube and accompanying otitis media with effusion were clearly visualized. In a patient with submucous cleft palate, abnormal arrangement of levator veli palatini muscles and possible deformity of the eustachian tube cartilage were found. Magnetic resonance imaging is expected to become a valuable tool for the diagnosis of nasopharyngeal and middle ear diseases.

Adolescent↗
PubMedDate not supplied

Pure-tone audiometry and auditory brainstem responses in noise-induced deafness.

PURPOSE: The objective of this study is to find the relationship between pure-tone audiometry results and the auditory brainstem response wave abnormalities. SUBJECTS AND METHODS: The pure-tone audiometry (PTA) and auditory brainstem responses (ABRs) from 22 patients (44 ears) with diagnosed noise-induced permanent hearing loss were studied. Three indices of PTA were average thresholds of 0.5 kHz/, /1 kHz, and 2 kHz (PTA1); 2 kHz and 4 kHz (PTA2); and 4 kHz (PTA3) were subdivided into 3 thresholds of hearing. Their relationships with ABR results were analysed. The patterns of PTA from various groups of ABR wave patterns were studied. RESULTS: In this study, the abnormal ABR wave patterns were detected in 72.7% of the ears. The ears with prolonged ABR wave latency, absent early waves, prolong interpeak wave I-V latency was 20.5%, 18.2%, and 21.1%, respectively. Normal ABRs were recorded in 27.3% of the ears despite marked thresholds elevation of the PTA at high frequencies. Other relationships between PTA results and ABR wave results were discussed. CONCLUSION: There were relationships between severity of noise-induced hearing loss indicated by PTA and the patterns of ABR wave abnormalities among workers with noise-induced permanent hearing loss.

Aged↗
PubMedDate not supplied

Comparison between human and armadillo Paracoccidioides brasiliensis isolates by random amplified polymorphic DNA analysis.

Sixty-three Paracoccidioides brasiliensis isolates obtained from three nine-banded armadillos (Dasypus novemcinctus), one Amazonian armadillo's and 19 clinical isolates were compared by random amplified polymorphic DNA analysis with the primer OPG-19. The isolates were divided into three major clusters, I, II and III. Coincidences between human and armadillo isolates were observed in clusters I and II. Cluster III consisted only of armadillos' isolates. The results suggested that (I) humans may acquire P. brasiliensis infection by contact with armadillo's environment, (II) there may be P. brasiliensis genotypes peculiar to the animal, and (III) individual armadillos may be infected with P. brasiliensis cells with different genotypes.

Animals↗
PubMedDate not supplied

Pathogenicities and GP43kDa gene of three Paracoccidioides brasiliensis isolates originated from a nine-banded armadillo (Dasypus novemcinctus).

We studied three different isolates of Paracoccidioides brasiliensis obtained from the mesenteric lymph node (D3LY1), the spleen (D3S1) and the liver (D3LIV1) of the same armadillo (Dasypus novemcinctus). Pulmonal inflammatory area was evaluated by intravenous inoculation of 10(6) yeast cells of each isolates in young, male, ddY mice. Moreover, the partial sequence of GP43kDa gene of P. brasiliensis was analyzed. The lung inflammatory area was greater in animals inoculated with isolate D3S1. The partial sequence of GP43kDa gene indicated that isolate D3S1 is different from isolates D3LY1 and D3LIV1. This study suggested that the same armadillo might be susceptible to multiple P. brasiliensis isolates simultaneously.

Animals↗
PubMedDate not supplied

Association of selenoprotein P with testosterone production in cultured Leydig cells.

Selenoprotein P, a plasma selenoprotein, is thought to act as an antioxidant in the testis, similar to glutathione peroxidase. mRNA encoding selenoprotein P was selectively expressed by Leydig cells, suggesting participation in testosterone production. On the other hand, testosterone production has been linked to O2 toxicity in cultured Leydig cells. The authors, therefore, examined changes in selenoprotein P mRNA expression and testosterone production following stimulation by a stable analog cyclic adenosine 3',5'-monophosphate (cAMP) in cultured Leydig cells (MLTC-1 cells) under normal O2 concentrations. Selenoprotein P mRNA was analyzed by Northern blotting, while testosterone concentration in culture medium was measured by radioimmunoassay. When cAMP was added to cultures at 0, 0.01, 0.1, or 1 mM, selenoprotein P mRNA expression showed dose-dependent stimulation. cAMP was added at 0.1 mM to cultures, and the selenoprotein P mRNA expression and testosterone concentration were evaluated after incubation times of 2, 5, 9, 15, or 24 h. Selenoprotein P mRNA expression was maximal at 9 h. Testosterone concentration in the medium also increased, becoming maximal at 15 h. Selenoprotein P induced in Leydig cells following cAMP stimulation may counteract O2 toxicity from cAMP-mediated increases in testosterone production.

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PubMedDate not supplied

Outcome of surgical treatment for obstructive azoospermia.

The efficacy of reanastomosis was evaluated in 30 patients with obstructive azoospermia, including 19 postvasectomy cases; 7 cases complicating inguinal herniorrhaphy; 2 cases with a characterized isolated congenital anomaly; 1 case of Young's syndrome; and 1 case with an unknown, possibly congenital cause. In the postvasectomy group. successful vasovasostomy was achieved in 15 of 18 cases (83.3%; 1 postvasectomy patient dropped out of the study prior to analysis). Duration of obstruction in the 3 cases where anastomosis failed was 6, 9, and 20 years. In the group where obstruction followed inguinal herniorrhaphy, unilateral vasovasostomy was performed in 6 cases, and transepididymovasostomy was performed in 1 case. Success was achieved in 3 of 6 cases (50%; 1 case was not included because failure of spermatogenesis was detected postoperatively). In all 4 remaining cases, microsurgical epididymovasostomy or transepididymovasostomy was performed, but success was achieved only in the case of Young's syndrome. Although mailed questionnaires and telephone interviews indicated occurrence of natural pregnancy in only 4 affected couples, postoperative sperm counts were relatively satisfactory as in previous reports.

Adult↗
PubMedDate not supplied

Effect of renal transplantation on sexual function.

This investigation was conducted to determine whether renal transplantation can improve sexual function in male patients with chronic renal failure. The authors retrospectively studied 121 men undergoing renal transplantation who complained of any type or degree of sexual dysfunction pre-operatively. Sexual function was evaluated by questionnaire which included erectile, ejaculative, and orgasmic functions. Pre- and postoperative frequency of sexual intercourse was also recorded. Patient characteristics, laboratory data, and endocrinologic profiles were analyzed to identify factors that might influence sexual function. In patients with hormonal determinations, results essentially normalized after transplantation. However, only 43 patients (35.5%) reported improvement of overall sexual function after renal transplantation, while 34 (28.1%) reported worsening. Although frequency of sexual intercourse was unaffected by transplantation, 15 of 20 patients who had no intercourse before transplantation initiated intercourse afterward. These 15 patients all underwent transplantation before 40 years of age. Comparisons of variables by sexual function showed significant differences for type of immunosuppressive treatment, interval after renal transplantation, and serum concentration of hemoglobin A1c. It is concluded that renal transplantation cannot improve sexual function in all patients, although hormonal profiles were largely normalized, and that renal transplantation should be encouraged at a younger age.

Adult↗
PubMedDate not supplied

Effect of lifestyle factors on infertility in men.

Environmental factors, changes in lifestyle and occupational exposures are responsible for declining human semen quality. We investigated the effects of history of surgery and lifestyle choices on infertility of 271 infertile men and 251 healthy volunteers. The frequency of varicocelectomy was significantly higher in infertile men (2.9%) than in controls (0.4%; P < 0.05). Alcohol use was significantly more common in infertile men (92%) than in controls (80%; P < 0.01). Satisfaction with sexual life was greater in controls (85%) than in infertile men (77%; P < 0.05). Other factors had no effect.

Adult↗
PubMedDate not supplied

Climacteric-like disorders in prostate cancer patients treated with LHRH agonists.

We assessed long-term side effects with characteristics of female climacteric disorders in prostate cancer patients treated with luteinizing hormone-releasing hormone (LHRH) agonists. Such side effects are not considered to be serious, though they can significantly affect patient quality of life. Sixty-four prostate cancer patients treated with LHRH agonists and 30 benign prostatic hyperplasia patients, as a control group, were surveyed by questionnaire. The median age of the cancer patients was 74.9 years old, ranging from 60 to 94 years, and the median LHRH agonist dosing period was 16.5 months, ranging from 1 to 64 months. The results of the questionnaires were compared between the patients and the controls, as well as between different variables. Sixty (93.8%) of 64 patients claimed symptoms similar to female climacteric disorders. Further, more than 50% of the symptoms included in the questionnaire were reported by 14 (21.9%) of the patients. Symptoms reported by the patients were more severe than those by the controls. Hot flashes, sleep disturbance, and fatigue recorded high scores in the patient questionnaires as compared with those of the controls. In addition, as the term of LHRH agonist use increased, complaints of sweating or coldness in hands and feet increased. Patients without bone metastasis frequently experienced heaviness in the head and headaches compared to those with bone metastasis. The results of our questionnaire-based outcome study showed that side effects similar to female climacteric disorders in prostate cancer patients treated with LHRH agonists were more severe than in the control group, which could be detrimental to quality of life and general well-being.

Aged↗
PubMedDate not supplied

Bromocriptine for infertile males with mild hyperprolactinemia: hormonal and spermatogenic effects.

To clarify the influence of hyperprolactinemia on spermatogenesis and steroidogenesis in infertile male patients, the serum prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol concentrations were and the effect of bromocriptine treatment on spermatogenesis was examined. A total of 1234 patients were evaluated and 147 men had hyperprolactinemia. Of these, only 30 had PRL concentrations more than twice the upper limit of normal and most of them had a little excess over the upper limit. For 10 of these 30, serum hormone concentrations were measured and semen was analyzed before and after bromocriptine administration. No relationship between the PRL and other hormone concentrations was found. No changes were noted in the LH, FSH, testosterone, or estradiol concentrations, or in the sperm density and motility after treatment. The mean PRL decreased from 26.5 +/- 4.5 to 1.4 +/- 1.8 ng/mL. In infertile men who are mildly hyperprolactinemic, bromocriptine administration does not improve semen analysis, although it does normalize the PRL.

Bromocriptine↗
PubMedDate not supplied

Age variation in the upper limit of hearing and amplitude of eye accommodation in childhood and adolescence.

The upper limit of hearing and amplitude of eye accommodation were examined, and their standard aging curves were established in order to evaluate their age-related changes in childhood and adolescence. The subjects were 2497 audiometrically and otologically normal ears and 2349 optometrically and ophthalmologically normal eyes ranging in age from 5 to 24 years in Japan. The upper limit of hearing was measured by the equipment made by us. The amplitude of eye accommodation was calculated at near point and far point measured by the ophthalmodynamometer. Both the upper limit of hearing and amplitude of eye accommodation became gradually less as age increased. The variability of the upper limit of hearing was less than that of the amplitude of eye accommodation. Standard aging curves were established in childhood and adolescence by calculating 10th, 25th, 50th, 75th and 90th centiles. There is no significant relationship between the upper limit of hearing and the amplitude of eye accommodation.

Accommodation, Ocular↗
PubMedDate not supplied

Right ventricular performance is impaired by full assist of left heart bypass. Analysis of right ventricular performance against change in afterload in heart failure models.

The purpose of this study was to assess right ventricular (RV) performance during left heart bypass (LHB) and to determine the optimum LHB driving conditions to preserve RV performance. LHB was established with a centrifugal pump in eight mongrel dogs weighing 11-19 kg. Failing heart models were induced by normothermic aortic clamping for 20 min. RV volume was measured by a conductance catheter, and RV performance was evaluated by two parameters. One was the slope of the RV end-systolic pressure-volume relationship (ESPVR) as a load independent index, and the other was the peak RV pressure (PRVP)-RV stroke volume (RVSV) relationship as a "force-velocity relationship." These parameters were measured during varying assist ratios of LHB at 0% to 100% of pulmonary artery flow, and varying afterload as induced by bilateral intrapulmonary balloon inflation. In failing hearts, RV ESPVR showed an inverse correlation, with the assist ratio of LHB significantly decreasing from 4.23 +/- 1.35 (mmHg/ml) to 3.52 +/- 1.30 (mmHg/ml; P < 0.05) after 100% LHB assist. The correlation between PRVP and RVSV also was inversely linear, the slope of this correlation becoming significantly steeper after 100% LHB assist compared to that without LHB (-0.131 +/- 0.042 vs. -0.051 +/- 0.038, P < 0.005). These two slopes intersected, and this intersection was considered the critical point of afterload above which RVSV was decreased by LHB compared to that without LHB. In addition, reducing the assist ratio made the slope of the PRVP-RVSV correlation significantly more gentle (70%: -0.072 +/- 0.037 vs. 100%: -0.131 +/- 0.042, P < 0.05), with the intersection of the two slopes shifting rightward (i.e., higher afterload). Consequently, the critical level of afterload at 70% LHB assist was significantly higher than that at 100% LHB assist (70%: 38.1 +/- 6.9 vs. 100%: 29.2 +/- 6.8, P < 0.05). Therefore, RV performance against afterload was improved by reducing the assist ratio of LHB. This study demonstrates that RV performance is impaired by full LHB assist if the RV afterload is above the critical level, and that reducing the assist ratio may improve RV performance against afterload.

Animals↗