Search PubMed⌕ Search

Biomedical subjects

K Yasuda

Publications and source records attributed to K Yasuda.

At least 271 records · Page 15Linked to original sources
PubMed2000

Overt congestive heart failure with mitral and aortic regurgitation due to antiphospholipid syndrome in a patient with systemic lupus erythematosus.

A 51-year-old woman with overt congestive heart failure with pleural and pericardial effusion was treated with furosemide and nifedipine, leading to improvement in her condition and a decrease in effusions. An echocardiography demonstrated mitral and aortic regurgitation with mitral valve prolapse, which caused the congestive heart failure. Since leukocytopenia and lymphocytopenia with arthralgia could be observed, serological investigations were performed. She was diagnosed as having systemic lupus erythematosus (SLE) with antiphospholipid syndrome, and started on a treatment of prednisolone and aspirin. Based on the treatment, the pleural and pericardial effusion went into complete remission, indicating that the serositis related to SLE had overlapped the heart failure. Since there was no evidence of any other diseases that could be responsible for the valvular lesions, we concluded that they were due to antiphospholipid syndrome. The administration of prednisolone had no significant effect on valvular morphology or function as demonstrated by echocardiography. When patients with valvular disease are seen, a valvulopathy related to antiphospholipid syndrome should be considered as part of the differential diagnosis.

Antiphospholipid Syndrome↗
PubMed2000

A hamster model of equine herpesvirus 9 induced encephalitis.

An acute and lethal infection of equine herpesvirus 9 (EHV-9), a new type of equine herpesvirus, was established in Syrian hamsters by intranasal inoculation. Clinical symptoms included the loss of body weight, nasal and ocular discharges and apparent neurological symptoms. Both LD50 and ID50 were equal at 33 plaque forming units. Histological and immunohistochemical examination demonstrated that the virus replicated in the olfactory mucosal cells and in the neurons of the olfactory bulbs, cerebrum and mesencephalon. The induction of encephalitis by intranasal but not by other routes of inoculation (i.v., i.p., i.m.) indicated that EHV-9 entered the brain via the olfactory nerve and then spread trans-synaptically to connecting neurons along the olfactory tract. This animal model should be useful for studying the pathogenesis and neurovirulence of this newly discovered neurotropic virus as well as other neurotropic herpesviruses.

Animals↗
PubMed2000

Altered expression of hepatic cytochromes P-450 in mice deficient in one or more mdr1 genes.

We hypothesized that the drug efflux protein P-glycoprotein (Pgp), the product of the multidrug resistance gene MDR1, might influence hepatic expression of CYP3A or other cytochromes P-450 (P-450s) because Pgp can transport endogenous regulators of these cytochromes. We began with variants of a CF-1 mouse strain containing a defective mdr1a gene that is inherited in a Mendelian fashion. The amount of CYP3A protein in liver was inversely related to the gene dose of the normal mdr1a allele in these mice. mdr1a knockout mice of either mixed (FVB x 129/Ola) or pure FVB genetic background and housed in Amsterdam display an increased expression of CYP2B and CYP3A proteins. However, because mdr1a ablation causes a compensatory increase in hepatic mdr1b (which can efflux intracellular glucocorticoids), we reasoned that mdr1b might mask the overall effect of mdr1a absence on P-450 gene expression. Targeted inactivation of the mdr1b gene increased P-450 expression, but the effect was modest compared with mdr1a ablation. Mice nullizygous for both mdr1a and mdr1b-type Pgps and kept in Amsterdam had dramatically increased levels of CYP3A protein as well as other P-450s examined and of the electron donor P-450 reductase. Consistent with the protein results, CYP3A catalytic activity measured as midazolam 1'- and 4-hydroxylation in liver microsomes from these knockout mice revealed a rank order of activities with mdr1a/1b > mdr1a > mdr1b > (+/+) mice. In contrast to results in mice housed in Amsterdam, in the genetically identical mdr1a or mdr1a/1b (-/-) male mice housed in the United States, hepatic P-450 expression was unaffected by mdr1 genotype or actually showed a slight decrease in mdr1a (-/-) mice. These results provide a revealing picture of mdr1-type Pgp as an upstream regulator of hepatic P-450 expression, and demonstrate that these pharmacologically relevant phenotypes in knockout mice depend not only on the genetic make-up of the mice but also on the environment.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Effect of functional continuous magnetic stimulation for urinary incontinence.

PURPOSE: We evaluated the therapeutic efficacy of continuous magnetic stimulation on urinary incontinence by studying the urodynamic effect on urethral closure and bladder inhibition. MATERIALS AND METHODS: A total of 11 patients with stress incontinence and 12 with urge incontinence (7 males and 16 females, mean age 55.8 years) were evaluated. In the pilot study urethral pressure profile was performed before and after 20 Hz. 15-minute (with 1-minute on/30-second off cycles) stimulation, and maximum intraurethral pressure was recorded during stimulation in stress incontinence cases. Cystometry was performed before and during 15-minute stimulation at 10 Hz. in urge incontinence cases. In the therapeutic study 8 females with stress incontinence, and 3 males and 5 females with urge incontinence were treated with magnetic stimulation twice a week for 5 weeks. RESULTS: In the pilot study maximum intraurethral pressure increased by 34% during stimulation and maximum urethral closure pressure increased by 20.9% (p = 0.0409) after stimulation in stress incontinence cases. In urge incontinence cases significant increases in bladder capacities at first and maximum desire to void during stimulation were noted (p = 0.0164 and 0.0208, respectively). In the therapeutic study 86% of 7 patients with stress incontinence and 75% of 8 with urge incontinence were improved, and 1 dropped out of the study. CONCLUSIONS: Continuous magnetic stimulation was effective on urethral closure and bladder inhibition, and as treatment of urinary incontinence.

Female↗
PubMed2000

The glucocorticoid receptor is essential for induction of cytochrome P-4502B by steroids but not for drug or steroid induction of CYP3A or P-450 reductase in mouse liver.

Cytochrome P-4503A, CYP2B, and P-450 reductase are induced by glucocorticoids, antiglucocorticoids such as pregnenolone 16alpha-carbonitrile, and drugs such as rifampin and phenobarbital. Although the pregnane X receptor is reported to mediate steroid and drug activation of CYP3A via a conserved cis-element in CYP3A genes, discrepancies exist between the induction of the endogenous CYP3A genes and the activation of the pregnane X receptor. It is a formal possibility that the glucocorticoid receptor may account for some of these discrepancies. To determine the requirement in vivo of the glucocorticoid receptor in expression of CYP3A and CYP2B, we compared the induction of these proteins in the livers of normal mice and mice with a targeted mutation in the glucocorticoid receptor. Mice lacking the glucocorticoid receptor show no difference in constitutive hepatic expression of CYP3A but show a decrease in the level of CYP2B. Glucocorticoid receptor-deficient mice challenged with either dexamethasone or pregnenolone 16alpha-carbonitrile failed to induce CYP2B proteins, whereas CYP2B was readily induced in (+/+) mice. In contrast, CYP3A and P-450 reductase proteins were induced by either inducer in wild-type and glucocorticoid receptor-null mice. Similarly, rifampin induced CYP3A in either wild-type or glucocorticoid receptor-null mice. Despite reports that rifampin is a nonsteroidal ligand for the human glucocorticoid receptor, rifampin failed to induce tyrosine aminotransferase in mice regardless of glucocorticoid receptor genotype, and rifampin did not compete for ligand binding to either mouse or human glucocorticoid receptor. Phenobarbital induced CYP3A, CYP2B, and P-450 reductase in all mice, but the amplitude of induction was diminished 37% in glucocorticoid receptor-null mice. Thus, there are distinctly different essential requirements of CYP3A, CYP2B, and P-450 reductase genes for the glucocorticoid receptor in their induction by steroids and drugs.

Aldosterone↗
PubMed2000

[The effect of prophylactic nicorandil infusion to reduce intraoperative myocardial ischemia during abdominal surgery in patients with risk factors of ischemic heart disease].

Three hundred patients who had undergone abdominal surgery with risk factors of ischemic heart disease (IHD), such as hypertension, diabetes mellitus, hyperlipidemia, smoking, advanced age, obesity, familial history, electrocardiographic abnormality, other perivascular disease, and male, were included in this study. Patients older than forty years were included in the study. They were divided into two groups for a randomized double blind trial: nicorandil was administered in one group (group N) and placebo in another (group C), and we investigated the effect of prophylactic nicorandil infusion to reduce intraoperative myocardial ischemia. ST segment in leads II and Vs was recorded by ST trend monitor from the time of patient's entering the operating room to the time to exit. Intraoperative myocardial ischemia occurred in 11 patients in group N and in 32 patients in group C (P < 0.0001). Prophylactic nicorandil infusion was effective to reduce intraoperative myocardial ischemia in patients with risk factors of IHD during abdominal surgery.

Abdomen↗
PubMed2000

[Myocardial ischemia score as a preoperative screening method for intraoperative myocardial ischemia].

Three hundred patients for abdominal surgery with risk factors of ischemic heart disease (IHD), such as hypertension, diabetes mellitus, hyperlipidemia, smoking, old age, obesity, familial history, electrocardiographic abnormality, other perivascular diseases and male, were included in this study. Patients older than forty years were included in the study. ST segment in lead II and V5 was recorded by ST trend monitor from the time of entering the operating room to the time of exit and intraoperative myocardial ischemia occurred in 58 patients (19.3%). Correlation coefficients between each risk factor of IHD and intraoperative myocardial ischemia were calculated by multiple regression analysis and myocardial ischemia score (MIS) was determined. Intraoperative myocardial ischemia increased in patients with more than 10 points of MIS by discriminant analysis and hitting ratio of MIS was 86.3%.

Aged↗
PubMed2000

Mitral valve repair and septal myectomy for hypertrophic obstructive cardiomyopathy.

Combined mitral valve repair using the sliding leaflet technique and septal myectomy were employed to successfully treat left ventricular outflow tract (LVOT) obstruction and mitral regurgitation due to hypertrophic obstructive cardiomyopathy (HOCM). A 46-year-old man was diagnosed with HOCM along with congestive heart failure and was treated medically. These symptoms, however, were resistant to medical treatments with a beta-blocker, a Ca-antagonist, and disopyramide, and he was referred to our hospital for surgery. Doppler echocardiography demonstrated an LVOT obstruction at rest with a peak pressure gradient of 138 mmHg. The interventricular septum thickness was 14 mm. Mitral regurgitation of 3+ with severe SAM was also observed. Temporary dual chamber pacing was tried without significant improvement. Following these examinations, the patient underwent surgery. A transaortic septal myotomy-myectomy was performed first, and the mitral valve was then approached through the left atrium. Mitral valve repair was performed with the sliding leaflet technique to reduce the height of the posterior leaflet from 2 cm to 1 cm. Postpump transesophageal echocardiography revealed no MR and a peak LVOT gradient of 15 mmHg. The patient recovered well except for a residual mild SAM, and MR2+. We therefore concluded that this surgical approach might provide results which are superior to those of myectomy alone.

Cardiomyopathy, Hypertrophic↗
PubMed2000

Angiotensin-converting enzyme-independent angiotensin formation in a human model of myocardial ischemia: modulation of norepinephrine release by angiotensin type 1 and angiotensin type 2 receptors.

Angiotensin II (Ang II) promotes norepinephrine (NE) release from cardiac sympathetic nerve endings. We assessed in a human model in vitro whether locally formed Ang II contributes to NE release in myocardial ischemia. Surgical specimens of human right atrium were incubated in anoxic conditions. After 70 min of anoxia, NE release (carrier-mediated; caused by NE transporter reversal) was 8-fold greater than normoxic release. Angiotensin-converting enzyme inhibition with enalaprilat failed to reduce anoxic NE release. In contrast, prevention of chymase-dependent Ang II formation with chymostatin, Bowman-Birk inhibitor, or alpha(1)-antitrypsin significantly inhibited anoxic, but not exocytotic, NE release. Two mast-cell stabilizers, cromolyn and lodoxamide, markedly reduced NE release, implicating cardiac mast cells as a major source of chymase. Angiotensin type 1 receptor (AT(1)R) blockade with EXP3174 inhibited NE release, whereas angiotensin type 2 receptor (AT(2)R) blockade with PD123319 did not. Interestingly, PD123319 reversed the inhibitory effect of EXP3174. Furthermore, synergisms were uncovered between EXP3174 and an AT(2)R agonist, and between EXP3174 and a Na(+)/H(+) exchanger inhibitor. Thus, angiotensin-converting enzyme-independent Ang II formation via chymase is important for carrier-mediated ischemic NE release in the human heart. Locally generated Ang II promotes NE release by acting predominantly at AT(1)Rs, which are likely coupled to the Na(+)/H(+) exchanger. Effects of Ang II at AT(2)Rs, seemingly opposite to those resulting from AT(1)R activation, are uncovered when AT(1)Rs are blocked. Because NE release is associated with coronary vasoconstriction and arrhythmias, and mast-cell density and chymase content increase in the ischemic heart, the notion that chymase-generated Ang II plays a major role in carrier-mediated NE release may have important clinical implications.

Aged↗
PubMed2000

[Clinical evaluation of hepatic blood flow and oxygen metabolism during thoracoabdominal aortic surgery using pulse dye-densitometry combined with hepatic venous oxygen saturation].

OBJECTIVE: There has been no report that pulse dye-densitometry (PDD), a novel non-invasive modality for monitoring hepatic blood flow (HBF), was applied during cardio-pulmonary bypass (CPB). We investigated weather PDD was useful to measure HBF during thoracoabdominal aortic surgery using partial CPB. Furthermore, HBF and hepatic metabolism were assessed during selective visceral perfusion or shunt using PDD, hepatic venous oxygen saturation (ShO2), and analysis of hepatic metabolic products. METHODS: A prospective study was carried out in eight patients who underwent thoracoabdominal aortic surgery from April 1998 to October 1999. Operative adjuncts were partial CPB with mild hypothermia in six (femoral veno-arterial bypass: FF group) and deep hypothermic circulatory arrest in two (DHCA group). Measurements were performed at following five time points; just before initiating CPB, just after establishing CPB, during selective visceral perfusion, during selective visceral shunt, and just after weaning CPB. RESULTS: Plasma clearance rate of indocyanine green measured by PDD well correlated with that obtained by in vitro spectrophotometry (p < 0.0001, R2 = 0.644). PDD demonstrated that decreased IIBF during selective visceral perfusion or shunt was well compensated by increased hepatic oxygen extraction rate in FF group and reduced oxygen consumption in DHCA group. Lactic acid extraction ratio and arterial ketone body ratio also decreased during this period. ShO2 during selective visceral shunt correlated with systemic systolic arterial pressure (SAP), and it showed a marked decrease under 20% when SAP was below 80 mmHg. Postoperative time course of serum total bilirubin and alanine aminotransferase of almost patients were within acceptable limits except the patient who required large amount of homologous blood transfusion. CONCLUSIONS: PDD proved to be a useful modality that enabled non-invasive monitoring of HBF even during partial CPB. Decreased HBF during selective visceral perfusion or shunt in thoracoabdominal aortic surgery was within physiological compensation, which led us conclude that it might be effective adjuncts, for visceral organ protection.

Adult↗
PubMed2000

Surgical results of Stanford type B aortic dissection. Comparisons between partial and subtotal replacement of the dissected aorta.

BACKGROUND: Surgical results for Stanford type B aortic dissection were retrospectively compared between the subtotal prosthetic replacement of the thoracoabdominal dissected aorta (STR) and partial replacement of the descending aorta at the intimal tear (PR). METHODS: Twenty-two patients (11 males and 11 females with mean age of 56.9+/-2.6 years) undergoing repair of aneurysms were analyzed. All operations were performed with the aid of femorofemoral partial cardiopulmonary bypass. Reconstruction of the critical artery for spinal cord blood supply was determined by evoked spinal cord potential (ESP) monitoring in non-urgent cases. Operative mortality and incidence of complications were compared between the PR group (Group I; n=15) and the STR group (Group II; n=7). RESULTS: There were one operative death and one late death in Group I. No early or late deaths occurred in Group II. Postoperative paraplegia occurred in 1 patient in Group I and 2 patients in Group II. Among patients undergoing selective reconstruction of the critical intercostal arteries, paraplegia occurred in only one patient. Incidence of postoperative complications was not significantly different between Group I and Group II. Presence of rupture (p<0.001) and development of acute renal failure (p<0.05) revealed significant determinants of postoperative mortality by multivariate analysis. Operative procedure did not influence postoperative mortality or occurrence of paraplegia. CONCLUSIONS: Operative results of STR with selective reconstruction of the critical arteries and PR for aortic dissection were comparable. Subtotal replacement of the thoracoabdominal dissected aorta is encouraged to apply for patients with diffuse, large postdissection aneurysms or those with a high risk of future enlargement of remaining false channels such as Marfan syndrome, under adequate reconstruction of the critical segmental arteries.

Acute Kidney Injury↗
PubMed2000

Directional preponderance in pitch circular vection.

We used optokinetic stimulation (OKS) in eighteen normal adults aged 18-30 years to investigate vertical self-motion perception. In order to induce self-rotation, either a stripe pattern or a random dot pattern was projected onto the inner wall of a hemispherical dome with a diameter of 150 cm. The pattern was rotated either about the subject's vertical axis (yaw) or about the subject's interaural axis (pitch) for 80 s at a constant acceleration of 1 deg/s2. Stimuli were randomly repeated three to four times in each direction. The latency of onset as well as the perceived intensity of circular vection (CV) was measured for each stimulus presentation. CV latencies for upward rotational stimulation were significantly longer than those for downward rotational stimulation under both types of stimulus conditions. There was no significant difference in CV latency between rightward and leftward rotational stimulation. For most subjects, the magnitudes of the perceived CV for rightward rotational stimulation were equal to those for leftward rotational stimulation, whereas the magnitudes of the perceived CV for vertical stimulation showed large intersubject variability. These results provide additional evidence that fundamental differences exist between different types of self-motion. Possible explanations for the directional asymmetry in vertical perception of self-motion will also be discussed.

Adult↗
PubMed2000

[A study of the minimum number of slices required for quantification of pulmonary emphysema by computed tomography].

We attempted to determine the minimum number of slices required for quantification of overall emphysema by computed tomography (CT). Forty-nine patients underwent CT scanning with a 15-mm slice interval, and 13 to 18 slices per patient were obtained. The percentage of low attenuation area (LAA%) per slice was measured with a method that we reported on previously, utilizing a CT program and NIH image. The average LAA% values for 1, 2, 3, and 6 slices evenly spaced through the lungs [LAA% (1), LAA% (2), LAA% (3), and LAA% (6)] were compared with those for all slices [LAA% (All)]. The correlation coefficients for LAA% (1), LAA% (2), LAA% (3), and LAA% (6) with LAA% (All) were 0.961, 0.981, 0.993, and 0.997, respectively. Mean differences +/- SD were -3.20 +/- 4.21%, -2.32 +/- 3.00, -0.20 +/- 1.84, and -0.16 +/- 1.26, respectively. From these results, we concluded that overall emphysema can be quantified by using at least three slices: one each of the upper, middle, and lower lung.

Adult↗
PubMed2000

[A comparative study of the prognosis for Japanese patients with idiopathic interstitial pneumonia or BOOP based on histopathologic subsets].

We explored the prognosis for 123 patients with either idiopathic interstitial pneumonia (IIP) or bronchiolitis obliterans organizing pneumonia (BOOP). All patients underwent either open lung biopsy or thoracoscopic lung biopsy procedures. The histopathologic diagnosis of IIP included patients with usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), and desquamative interstitial pneumonia with respiratory bronchiolitis-associated interstitial lung disease. The prognosis was poorest for patients with a histologic diagnosis of UIP, and excellent for those who received a diagnosis of BOOP. Although the prognosis is generally considered to be good for patients with NSIP, some NSIP patients in our study died. Histopathologic diagnosis based on surgical lung biopsy is useful in evaluating the prognosis for patients with IIP.

Aged↗
PubMed2000

Biofeedback training for detrusor overactivity in children.

PURPOSE: We evaluated biofeedback training for incontinence due to detrusor overactivity in children. MATERIALS AND METHODS: Included in our study were 22 boys and 17 girls with a mean age of 11.2 years. We noted nighttime incontinence in 3 patients, nighttime incontinence and daytime urinary symptoms in 26, and daytime incontinence in 10. All patients had detrusor overactivity and incontinence refractory to conventional treatment, including bladder training, tricyclic antidepressants, anticholinergics, desmopressin and/or conditioning therapy. Urodynamic study was performed using an 8Fr double lumen transurethral catheter for cystometry, a double balloon transrectal catheter for rectal pressure and external anal sphincter pressure measurement, and surface electrodes for sphincter electromyography. During biofeedback training patients were instructed to contract the anal sphincter without raising abdominal pressure to inhibit overactive bladder contractions. Biofeedback training was repeated monthly until cystometry revealed a stable bladder or lower urinary tract symptoms improved considerably. RESULTS: Four patients were lost to followup. Of the remaining 35 children urinary symptoms were cured in 23 and improved in 4. Urodynamic studies after 6 months of biofeedback training in 33 cases showed that bladder overactivity disappeared in 10 and improved in 18. Bladder capacity at the initial desire to void and maximum cystometric capacity increased significantly (p = 0.0115 and <0.0001, respectively). Detrusor-sphincter dyssynergia in 2 patients before biofeedback training resolved in each after therapy. CONCLUSIONS: Biofeedback training for detrusor overactivity is effective even in pediatric cases refractory to conventional treatment.

Biofeedback, Psychology↗
PubMed2000

Concomitant abdominal aortic aneurysm repair and cholecystectomy. Combination of retroperitoneal aortic reconstruction and gassless laparoscopic cholecystectomy.

The coexistence of cholelithiasis and abdominal aortic aneurysm is not uncommon. However, cholecystectomy at the time of abdominal aortic reconstruction has generally been delayed because of the potential contamination of the graft. The case described here had concomitant cholelithiasis and abdominal aortic aneurysm, both of which were required to be treated, and was successfully treated with a combination of retroperitoneal abdominal aortic reconstruction and gasless laparoscopic cholecystectomy.

Aortic Aneurysm, Abdominal↗