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Biomedical subjects

T Mitsui

Publications and source records attributed to T Mitsui.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Acetylcholine receptor knockout mice].

To identify the functions of nicotinic or muscarinic acetylcholine receptor (nAChR or mAChR) subtypes, mice lacking beta 2 nAChR, alpha 4 nAChR, alpha 7 nAChR, M1 mAChR, and M2 mAChR have been generated. All these mice grow to normal size, and show no obvious physical or neurological deficit. However, pharmacological, biochemical, electrophysiological, neuroanatomical, and behavioural analyses revealed important functions of these AChR subunits. The beta 2 nAChR is most widely expressed in the central nervous system, and is involved in the functional high-affinity nicotine receptor regulating cognitive performance and the mesolimbic dopamine system. Aged beta 2-/- mutant mice showed neocortical degeneration and impaired spatial learning, and may serve as one possible animal model for dementias. The alpha 4 nAChR is associated mainly with the beta 2 subunit, and may form a component of the nicotinic pain pathways modulating the antinociceptive effect of nicotine. The alpha 7 nAChR mediates fast nicotinic currents in the hippocampus, and is not essential for normal neuronal development nor neurological function. The M1 mAChR mediates M current modulation in sympathetic neurons and the induction of seizure activity in the pilocarpine model of epilepsy. The M2 mAChR functions in the extrapyramidal system, hypothalamus, and spinal and/or spraspinal muscarinic pain pathways, and is possibly involved in locomotor performance, temperature control, and antinociceptive responses, respectively.

Animals↗
PubMed1998

Effects of mouth cleansing on the levels of exhaled nitrous oxide in young and older adults.

Nitrous oxide (N2O) is produced by denitrification, i.e. by microbial reduction of nitrate (NO3-). Our previous studies have established an analytical method for demonstrating the existence of N2O in exhaled air, and we showed that levels of N2O in exhaled air increase with age after puberty. However, the source of this change and its biological significance are still unclear. The purpose of this study was to examine whether the oral microorganisms are the main source of N2O. We measured exhaled N2O in 35 young adults (aged 19-29 years) and 34 older adults (aged 61-79 years) before and after mouth cleansing. N2O was measured using an infrared-photoacoustic analyzer equipped with an optical filter (UA0985, 2215 cm-1). Participants were classified as producers and non-producers according to the levels of exhaled N2O relative to the level in the atmosphere. N2O production differed significantly between the young adult producers and the older adult producers. Mouth cleansing resulted in an immediate reduction in exhaled N2O in both groups. We only found seven (20.0%) producers in the young, and 32 (94.1%) producers in the older after mouth washing. The differences before and after mouth cleansing were significant in both groups (P < 0.01 in the young and P < 0.05 in the older). The oral cavity is a major source of N2O. However, since approximately half-levels of N2O were still observed in exhaled air after mouth, cleansing, there may exist another N2O source in the human body.

Adolescent↗
PubMed1998

Novel breakpoints of the EWS gene and the WT1 gene in a desmoplastic small round cell tumor.

We report here a 15-year-old boy with an intraabdominal desmoplastic small round cell tumor (DSRCT). Cytogenetic analysis of the tumor cells showed the chromosomal translocation (11;22). Reverse-transcriptase polymerase chain reaction and sequencing analysis revealed a chimeric transcriptional message of the EWS gene exon 10 fused to the WT1 gene exon 8. The typical chimeric transcript seen in DSRCT is an in-frame fusion of EWS exon 7 to WT1 exon 8. The tumor in this case had a novel and longer chimeric transcript, which should be a potent transcription factor. Genetic analysis is a very powerful and specific aid in the differential diagnosis of small round cell tumors.

Abdominal Neoplasms↗
PubMed1998

Induced potential model for muscular contraction mechanism, including two attached states of myosin head.

The model for myosin head motion along an actin filament as proposed by Mitsui & Chiba [(1996). J. theor. Biol. 182, 147-159] is here modified so that it can explain the isometric tension and isotonic velocity transients having the same parameter values as the stationary filament sliding. The modified model differs in that a myosin head forms a complex with two actin molecules in an actin filament and has two attached states in the complex instead of three. Thus an incremental step in the myosin head motion is equal to the F-actin monomer repeat (5.46 nm). Muscle properties concerning the stationary filament sliding are calculated with new parameters in a manner similar to that of Mitsui-Chiba, with the results being qualitatively similar to theirs. In studying the transient phenomena, a quantitative expression is given for the potential energy of the myosin head in the complex, and two rate constants are applied to the kinetics of the head. The time course of tension recovery after a quick length change is determined by calculating the statistical distribution of the head in the two attached states, which conforms to experimental observations by Ford et al. [(1977). J. Physiol. 269, 441-515]. The tension variations T1/T0 and T2/T0 calculated with parameters determined from the analysis of stationary filament slidings are in fairly good agreement with the experimental data by Ford et al. The model suggests that a large fluctuation exists in the relative position between the actin and myosin filaments even when the load on a muscle is kept constant. Taking this fluctuation into account explains the characteristics of the isotonic velocity transient observed by Civan & Podolsky.

Actins↗
PubMed1998

Mitral reoperation via right thoracotomy in a patient with pulmonary hypertension.

A 62-year-old woman with pulmonary hypertension underwent mitral valve re-replacement through right thoracotomy. Severe adhesion occurred to the right lung. During pleural dissection the lung collapsed under single-lung ventilation, rapidly elevated pulmonary vascular resistance caused hemodynamic instability. When pulmonary hypertension is preoperatively present, this approach under single-lung ventilation is not recommended.

Female↗
PubMed1998

Aortic dissection extending from ductus diverticulum aneurysm.

We report the case of a 28-year-old woman with type B chronic aortic dissection extending from a ductus diverticulum aneurysm. The patient was successfully treated by interposition of a Hemashield 26-mm woven Dacron graft with a left posterolateral thoracotomy approach. Circulatory arrest through profound hypothermia and short retrograde cerebral circulation were employed during proximal anastomosis of the graft.

Adult↗
PubMed1998

Effects of (+)-8',8',8'-trifluoroabscisic acid on alpha-amylase expression and sugar accumulation in rice cells.

The effects of (+)-8',8',8'-trifluoroabscisic acid (trifluoro-ABA) on alpha-amylase expression were studied in rice embryoless half-seeds, scutella, and suspension-cultured cells derived from the embryo, and the effects of the analog on sugar accumulation were also studied in scutella and suspension-cultured cells. Treatment with (+)-trifluoro-ABA strongly inhibited the gibberellic acid-inducible expression of alpha-amylase I-1 encoded by RAmy1A in the aleurone layers of embryoless half-seeds at the levels of transcription, protein synthesis, and enzyme activity. It was also found that (+)-trifluoro-ABA stimulated (i) the uptake of glucose from the incubation medium and (ii) the synthesis of sucrose in scutellar tissues and suspension-cultured cells of rice. The biological activity of (+)-trifluoro-ABA was found to be more potent and persistent than that of natural ABA. We further examined the effects of trifluoro-ABA on the expression of alpha-amylase I-1 in scutellar tissues and suspension-cultured cells. It was found that (+)-trifluoro-ABA did not inhibit the formation of alpha-amylase I-1 in the absence of external glucose. However, glucose and (+)-trifluoro-ABA cooperatively suppressed the formation of alpha-amylase I-1. Judging from these results, we conclude that the regulatory mechanism for the expression of alpha-amylase I-1 in the scutellar epithelium is distinguishable from that operating in the aleurone layer.

Abscisic Acid↗
PubMed1998

Suppression of prostanoid formation and regulation of peripheral circulation after surgery using thrombin inhibitor (MD805).

We studied the effects of thrombin generation due to surgical stress on prostanoid formation and peripheral circulation in anesthetized dogs. Three experimental groups were used, consisting of a control group (group 1), a thoracotomized group (group 2), and a thoracotomized group treated with thrombin inhibitor (MD805: a synthetic arginine derivative) (group 3). The plasma concentrations of thrombin-antithrombin III complex (TAT) and prostanoids were measured along with the hemodynamic parameters. The plasma concentrations of TAT and thromboxane B2 significantly increased 1h after a thoracotomy in group 2. However, neither concentration increased after a thoracotomy in group 3. The flow ratio of the brachial and femoral arteries to cardiac output significantly decreased 1h after a thoracotomy in group 2. This study indicates that thromboxane A2 was thus synthesized by the stimulation of endogenous thrombin, while it also reduced the peripheral blood flow after surgery.

Animals↗
PubMed1998

Repeat coronary artery bypass in a patient with liver cirrhosis.

The case of a 69-year-old man with liver cirrhosis, thrombocytopenia, unstable angina, and a history of previous coronary artery bypass grafting (CABG) is presented. The patient under-went successful repeat CABG through lateral thoracotomy on the beating heart without extracorporeal circulatory support.

Aged↗
PubMed1998

An approach for acute disruption of large arteries in patients with advanced cervical cancer: endoluminal balloon occlusion technique.

OBJECTIVE: To test the feasibility of an intraluminal balloon occlusion technique for the control of sudden arterial disruption from cervical branches in patients with advanced malignancy. BACKGROUND: A sudden disruption of large cervical arteries is a devastating complication of advanced cervical malignancy and local infection. METHODS: Three patients with this complication underwent endoluminal balloon occlusion before surgical management. A double-lumen balloon catheter was introduced from the femoral artery to the bleeding point. Angiographic examination of the intracranial cross-filling could be performed by the injection of contrast medium from the opposite carotid artery, and consciousness levels could be directly confirmed under unilateral carotid occlusion. RESULTS: Resection of the carotid or innominate artery was safely performed in all the patients. No neurologic complications occurred. Bleeding did not recur during follow-up (range 5-32 months). CONCLUSIONS: This experience, although limited, suggests that surgical intervention to control cervical arterial bleeding with intraluminal balloon occlusion prevents excessive bleeding, decreases the risk of damage to the central nervous system, and improves the outcome in these critically ill patients.

Acute Disease↗
PubMed1998

CD48 expression on leukocytes in infectious diseases: flow cytometric analysis of surface antigen.

BACKGROUND: The function of CD48, one of the pan leukocyte cell surface antigens, is not yet well understood. CD48 was recently shown to enhance the CD40-mediated activating signal to B lymphocytes. As CD48 is one of the activation antigens of monocytes, neutrophils and lymphocytes, a change of its expression on the cells could be expected in infectious diseases. METHODS AND RESULTS: Leukocytes from 27 healthy controls and 97 patients with various infectious diseases were stained with anti CD48 antibody and analyzed by flow cytometry. On monocytes and neutrophils, the CD48 expression was increased in all of the patients with varicella, measles, rubella, infectious mononucleosis, streptococcus tonsillitis, sepsis and appendicitis. On lymphocytes, a significant increase of CD48 was also detected in the patients with the same diseases, except those with sepsis or appendicitis. The normalization of increased CD48 expression was confirmed on monocytes at the convalescent phase. CONCLUSION: These data suggest that CD48 expression on leukocytes reflects the disease activity of infectious diseases, especially of viral infections.

Adolescent↗
PubMed1998

Vesicourethral dysfunction following radical surgery for rectal carcinoma: change in voiding pattern on sequential urodynamic studies and impact of nerve-sparing surgery.

OBJECTIVES: Urodynamic studies were performed to clarify vesicourethral dysfunction and recovery after rectal surgery for cancer. MATERIALS AND METHODS: At 1, and 6 to 1 2 months after rectal surgery interviews and urodynamic studies (UDS) were performed on 51 consecutive patients, all without a prior history of voiding disorder (40 males and 11 females; median age, 60 years). Patients were divided into 2 groups, either with (preserved group, n = 17) or without (nonpreserved group, n = 34) preservation of the bilateral pelvic plexus during surgery. Comparisons of voiding status and urodynamic parameters were made between the 2 groups. RESULTS: By 1 and 6 months after the operation normal voiding was achieved in 71% (12/17) and 100% (13/13) of patients in the preserved group, and 6% (2/34) and 30% of patients (9/30) in the nonpreserved group, respectively (P < 0.001). Attainment of normal voiding in the nonpreserved group was preceded by the recovery of bladder sensation, while UDS demonstrated increases in vesical compliance and the disappearance of vesical denervation supersensitivity. CONCLUSION: A nerve-sparing procedure during radical surgery for rectal carcinoma preserved vesicourethral function. The urodynamic parameters relevant to postoperative recovery of voiding function were improved vesical compliance, disappearance of vesical denervation supersensitivity, and recovery of a bladder filling sensation.

Adult↗
PubMed1998

Persistent vesicourethral dysfunction following radical surgery for rectal carcinoma: urodynamic features and potential abatement with modified sphincterotomy (radical transurethral resection of the prostate).

BACKGROUND: Vesicourethral function returns after radical rectal surgery during the first year but rarely progresses after 1 year. We examined the urodynamics of patients whose voiding dysfunction remained after 1 year, and treated several with a modified sphincterotomy procedure similar to radical transurethral resection of the prostate. METHODS: We analyzed the urodynamic features of vesicourethral dysfunction in 16 male patients with persistent voiding dysfunction for more than 1 year following radical surgery for rectal carcinoma. Seven patients elected to undergo radical transurethral resection of prostate (radical TUR-P) for the relief of their persistent voiding dysfunction. RESULTS: The mean bladder volume at the first desire to void was 210 mL, the mean maximal bladder capacity was 343 mL, and the mean vesical compliance (Cves) was 27.1 mL/cm H2O. All patients demonstrated either vesical denervation supersensitivity (Vds) or uninhibited contraction. The mean maximal urethral closure pressure was 43.9 cm H2O, and urethral denervation supersensitivity was found in 77.8% (7/9), and sphincter dyssynergia in 66.7% (6/9) of patients. After radical TUR-P, 5 patients became free from the use of self-catheterization, 1 patient had a reduced residual urine rate, and 1 patient was unchanged, but no patient noted a change in urinary control. CONCLUSION: Urethral dysfunction after radical rectal surgery was caused by failure of the bladder to empty along with an underactive detrusor. Radical TUR-P was effective in restoring voiding function in a selected group of these patients.

Aged↗
PubMed1998

A cause of sudden death: rupture of thoracic aortic aneurysm.

Sudden death occurred during antihypertensive therapy of a Stanford type A dissecting aortic aneurysm. Hemodynamic and electrocardiographic events were recorded including deterioration of ventricular fibrillation 4 minutes after rupture.

Aortic Aneurysm, Thoracic↗
PubMed1998

[Inflammatory reactions and microorganisms cultured from sputum and blood in association with terminal stage infection of patients with lung cancer].

We reviewed our experience with terminal stage infections in patients with lung cancer over an 11 year period at Kurume University Hospital. In patients with end-stage lung cancer, the infection is common and a mortal disease. We examined the clinical features and significance of pathogenic microbes isolated from sputum and blood in patients with lung cancer during their last month. Bacteriological examinations from blood done frequently in patients with episodes of fever revealed that bacteremia was one of the most important disease in terminal stage infection. In the blood cultures from the 22 patients various species of pathogenic microbes were recovered, and nine of which were fungi; five Candida albicans, three Candida tropicalis and one Candida parapsilosis. The major species of bacteria isolated from sputum were Staphylococcus aureus, including methicillin-resistant strain, and Gram-negative bacilli; P. aeruginasa, A. calcoaceticus, K. pneumoniae and E. cloacae, which are known to be frequently involved in hospital-acquired infections. However, S. pneumoniae and H. influenzae which were well known to be microbes of respiratory infections were rare. We concluded that we had to reveal the feature of terminal stage infection in order to reduce the fee for medical treatment and improve the QOL of patients with terminal stage lung cancer.

Bacteremia↗