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Biomedical subjects

Y Kato

Publications and source records attributed to Y Kato.

At least 55 records · Page 3Linked to original sources
PubMed2004

Present characteristics of symptomatic Entamoeba histolytica infection in the big cities of Japan.

Medical records, for 2000 and 2001, of symptomatic amoebic patients who were treated at our hospitals in Tokyo, Yokohama and Osaka were studied retrospectively for the purpose of gathering epidemiological data on symptomatic Entamoeba histolytica infection. A total of 58 patients were treated. Fifty-five of them were male, and 96% of the male patients were Japanese. The mean age of patients was 44.9 years old, and 91% of patients contracted the disease in Japan. Fifty-six per cent of the male patients indicated that they were practising homosexuals, and 44% of the male patients denied these practices or left the question unanswered. The serum Treponema pallidum haemagglutination test was positive in 45% of the patients, and antibody to human immunodeficiency virus (HIV) was positive in 45%. Our study revealed that recent symptomatic E. histolytica infection almost exclusively afflicted middle-aged males in the big cities of Japan, that a majority of the patients were probably exposed to the causative organism during homosexual activity, and that an increasing number of patients will be co-infected with HIV.

AIDS Serodiagnosis↗
PubMed2004

Improvement of dermatitis by iontophoretically delivered antisense oligonucleotides for interleukin-10 in NC/Nga mice.

IL-10 is overexpressed in skin lesions of atopic dermatitis (AD) patients and believed to be an important factor in the pathogenesis of the disease. Thus the regulation of IL-10 production is a potential solution for immunotherapeutic intervention in AD. We examined the topical delivery of an antisense oligonucleotide for mouse IL-10 (AS6) and the therapeutic effect on the skin lesions of NC/Nga mice, a human AD model. Using an iontophoresis system, about 30% of the applied dose of AS6 penetrated the skin and was distributed in the epidermis and upper dermis. Topically delivered AS6 decreased the levels of mRNA and protein of IL-10 in the lesions of NC/Nga mice, with no effect on IL-4 levels. The dorsal lesions of NC/Nga mice disappeared with repeated topical application of AS6. Topically delivered AS6 showed an inhibitory effect on the production of IL-10 in the skin lesions of NC/Nga mice and had a therapeutic effect on the established dermatitis.

Animals↗
PubMed2004

Role of women in medicine: a look at the history, the present condition and the future status of women in the surgical field, especially neurosurgery.

We have analyzed the historical background of women's progress in medicine in Japan and the role of female neurosurgeons as models for the next generation. Female neurosurgeons were asked to complete a questionnaire regarding their professional life in detail and the problems they are facing while managing their personal life after getting married and having a child. Some feel that there remain some constraints at work for being a female, due to their male colleagues who are not so understanding in nature. The younger generation is not so keen on joining the neurosurgical branch as their life career due to hard work and complete dedication demanded by neurosurgery. It is not easy for all to manage a neurosurgical career along together with a married life and children. Hence it is now time for those successful female neurosurgeons to become role models. Government can play an important role in these social reforms by coming up with programs to give social security to females and initiate programs for child care for married females pursuing such a demanding profession. Certain measures to encourage females to take up surgery are providing more time by arranging care for babies and families, flexibility in working hours, in addition to having a considerate husband and a considerate chief of department and senior staff. Departmental policies need to be completely impartial and should promote everyone based on their skills and knowledge. Women neurosurgeons need to get together and discuss all these issues so that the younger generation will not hesitate to take up this profession and become stalwarts of neurosurgery like their male counterparts.

Adult↗
PubMed2004

Prediction of impending rupture in aneurysms using 4D-CTA: histopathological verification of a real-time minimally invasive tool in unruptured aneurysms.

The authors describe the use of a 4D-CT angiogram to predict impending rupture in intact aneurysms, as a real-time, less invasive imaging technique. Histopathological verification and immunostaining of the bleb site performed on the study population reveals the significant predictive value of this tool. The point of maximum amplitude of pulsation of the aneurysm wall in unison with the RR interval of the electrocardiogram determines the potential rupture point. This helps in prioritizing the intervention for unruptured aneurysm cases, provides an effective screening of the high-risk population, and aids preoperative planning of clip application.

Aneurysm↗
PubMed2004

Outcome of surgery for small cell lung cancer -- response to induction chemotherapy predicts survival.

BACKGROUND: The role of surgery for local control of small cell lung cancer (SCLC) is controversial. METHODS: Sixty-nine consecutive patients who underwent complete resection of SCLC in our hospital were reviewed. The patients included 62 men and 7 women. Clinical stage at the time of diagnosis was c-stages IA and B in 29, c-stages IIA and B in 12, c-stage IIIA in 21, and c-stage IIIB in 7. RESULTS: Thirty-two patients received induction chemotherapy, and 37 patients underwent initial surgery. The overall response rate to induction chemotherapy was 71.9 %. The survival rate stratified by clinical stage at the time of diagnosis was 48.9 % for c-stage I, 33.3 % for c-stage II, 20.2 % for c-stage IIIA, and 0 % for c-stage IIIB. Downstaging after induction chemotherapy conferred a survival benefit. Survival after lobectomy or bilobectomy was better than after pneumonectomy. Patients who received adjuvant chemotherapy survived longer than patients who did not. CONCLUSIONS: Surgery combined with chemotherapy is a therapeutic option in selected patients with SCLC. Pathologic nodal status and response to induction chemotherapy are predictors of survival.

Aged↗
PubMed2004

In vitro metabolism of [14C]methoxychlor in rat, mouse, Japanese quail and rainbow trout in precision-cut liver slices.

1. The in vitro metabolism of [14C]methoxychlor (MXC) has been studied using precision-cut liver slices from the Sprague-Dawley male rat, CD-1 male mouse, WE strain male Japanese quail and juvenile rainbow trout (Oncorhynchus mykiss). The results demonstrated integrated phase I and II metabolism of MXC and species differences in the metabolic profiles were observed. 2. In rat liver slice preparations, MXC was rapidly metabolized to bis-OH-MXC by sequential O-demethylation followed by subsequent O-glucuronidation forming bis-OH-MXC glucuronide. No mono-OH-MXC glucuronide was detected. The doubly conjugated metabolite, bis-OH-MXC 4-O-sulphate 4'-O-glucuronide, was also detected as a rat-specific metabolite. 3. Formation of mono-OH-MXC and its glucuronide was the main metabolic pathway in the mouse and Japanese quail. In contrast to the rat, only minor amounts of bis-OH-MXC glucuronide were detected. A reductively dehalogenated metabolite, dechlorinated mono-OH-MXC glucuronide, was observed only in mouse preparations. 4. In rainbow trout, comparative amounts of both mono- and bis-OH-MXC glucuronide were formed as the major metabolites. Unconjugated forms of these metabolites were detected only as minor products. 5. The different metabolic profiles of MXC observed in the four animal species are possibly due to substrate specificity of contributing CYP450 monooxgenase enzyme(s) in different animal species.

Animals↗
PubMed2004

Presence of staphylococcal exfoliative toxin A in sera of patients with atopic dermatitis.

BACKGROUND: It has been reported that the toxins that Staphylococcus aureus produces are associated with the exacerbation of atopic dermatitis (AD). It has been shown in many studies that staphylococcal enterotoxin (SE) A and SEB contribute to AD by humoral immunity through IgE production as a superantigen. On the other hand, little attention has been paid to the relationship between AD and exfoliative toxin x (ETx). OBJECTIVE: We investigated the toxins that are frequently detected from the skin of patients and how these toxins affect AD. METHODS: S. aureus, isolated from the skin of 100 patients with mild to severe AD, were examined for the producibility of toxins by polymerase chain reaction. Serum samples were obtained from 21 patients with mild and moderate AD. The levels of SEB, ETA, total IgE, specific IgE, and specific IgG in sera were measured by ELISA. RESULTS: SEB was most frequently detected from S. aureus on the skin of these patients as previously reported. And ETx, to which little attention has been paid so far, was frequently detected next to SEB. Furthermore, ETA was detected from the sera of almost all the AD patients. SEB was not detected at all. Although the level of ETA in the AD group was significantly higher than that of controls, ETA-specific IgE was not detected from their sera. High levels of ETA tended to be detected from infantile patients. Although there were no significant differences in the levels of ETA-IgG between AD and the controls, its prevalence was more than twice as high as the controls in AD. CONCLUSION: These results suggest that many AD patients were exposed to ETx. We conclude that ETx may contribute to exacerbation of AD, particularly in infants, by a mechanism that is not through specific IgE production, unlike SEB.

Adolescent↗
PubMed2004

Immunological cell situation in the skin of atopic model mice.

BACKGROUND: We observed nishikinezumi, cinnamon-coloured (NC)/Fujita (F) mice aged between 5 and 28 weeks. These NC mice have skin eruptions that resemble human atopic dermatitis (AD) under conventional circumstances. OBJECT: We investigated the skin of eruptive and non-eruptive lesions in NC/F mice by using haematoxylin-eosin (H&E) staining, toluidine blue staining and immunohistopathological study with immunoglobulin (Ig)EepsilonRI, CD23, interleukin (IL)-4, IL-5, interferon (INF)-gamma and Ia antigen. RESULTS: Histological examination of the eruptive lesions revealed the perivascular infiltration of many lymphocytes and mast cells into the upper dermis. Intracellular oedema of the epidermis, lymphocyte infiltration into the epidermis and liquefaction degeneration of the basal layer were also observed. The numbers of IL-4 and IL-5 positive cells in the eruptive lesions were larger than those of the non-eruptive lesions. IL-4 and IL-5 positive cells in the eruptive lesions increased weekly. Some IFN-gamma positive cells were observed in the eruptive lesions after 21 weeks. IFN-gamma positive cells were scarce in the skin of both the non-eruptive and eruptive lesions before 21 weeks. Serum IgE increased from 7 weeks to 21 weeks. DISCUSSION: We confirmed that these findings indicated that T helper (Th)2-dominant immunological activation transformed to a Th1-dominant situation. Many IgEepsilonRI positive cells were recognized in the dermis of the eruptive lesions by the time IgE had decreased. We assumed that the dermatitis before 21 weeks was an IgE-mediated allergy. We have previously reported that older NC/F mice had positive patch-test reactions to mites. Because serum IgE decreased after 21 weeks, dermatitis after 21 weeks might be associated more with cell-mediated delayed hypersensitivity than with IgE-mediated immediate allergy.

Animals↗
PubMed2004

Quantitative analysis of the effects of hyaluronan and aggrecan concentration and hyaluronan size on the elasticity of hyaluronan-aggrecan solutions.

We determined elasticity (G') and viscosity (G'') of various aggrecan-hyaluronan solutions using a controlled-stress rheometer with high (10 Hz) to low (0.1 Hz) frequencies. Aggrecan solution (50 mg/ml) alone showed little elasticity at any frequency, but the addition of 3300 kDa hyaluronan at 0.001-0.1 mg/ml markedly increased the elasticity, but not the viscosity, at all frequencies. Increasing hyaluronan concentration at >0.1 mg/ml did not further increase the elasticity of the aggrecan solution, and the elasticity of the aggrecan-hyaluronan complex solution reached a plateau at a 500:1 (w/w) ratio. In studies with increasing concentrations of aggrecan and a constant concentration (0.5 mg/ml) of 3300 kDa hyaluronan, aggrecan induced elasticity only at >20 mg/ml, indicating the presence of a critical concentration for elasticity. In the presence of 50 mg/ml aggrecan, 1000 kDa hyaluronan had far less effect on the elasticity of the aggrecan solution than did 3300 kDa hyaluronan. These findings suggest that only approximately 50% reduction in aggrecan concentration (<20 mg/ml), or reduced hyaluronan size (<1000 kDa)--compared with their physiological levels in young cartilage--can abolish the elastic network of the aggrecan-hyaluronan complex.

Aggrecans↗
PubMed2004

Association of habitual long-distance running with the thickness of skeletal muscles and subcutaneous fat in the body extremities and trunk in middle-aged men.

AIM: We investigated the association of habitual long-distance running with the thickness of skeletal muscles and subcutaneous fat in the body extremities and trunk in middle-aged men using ultrasonography. METHODS: Three groups of healthy middle-aged men [mean (SD), 62.1 (2.8) years] took part in this investigation: a high-level group of 11 master runners who had competed in a 42.195 km race and run 51.6 (21.7) km every week, an intermediary-level group of 10 master runners who had competed in a 5-20 km race and run 9.3 (4.9) km every week, and a low-level group of 7 untrained men who continued to do no systematic training. The muscle thickness at 8 sites and the subcutaneous fat thickness at 10 sites were measured by B-mode ultrasonography, and were compared among the 3 groups. RESULTS: The high-level group had 10.0(-1)5.2% higher values for muscle thickness at the erector spinae, hamstrings, tibialis anterior, and triceps surae, compared with the intermediary-level and the low-level groups (p<0.05-0.001). The thickness of the subcutaneous fat about the rectus abdominis and external oblique was lower in the high-level group than in the intermediary-level and the low-level groups (p<0.05). CONCLUSIONS: Middle-aged male master athletes who habitually run at a high level have more muscle thickness in the lower extremities and trunk, and less subcutaneous fat thickness in the central regions of the body than do middle-aged men who habitually run at an intermediary level or do not run at all.

Abdominal Muscles↗
PubMed2003

Local manipulation of nuclear spin in a semiconductor quantum well.

The shaping of nuclear spin polarization profiles and the induction of nuclear resonances are demonstrated within a parabolic quantum well using an externally applied gate voltage. Voltage control of the electron and hole wave functions results in nanometer-scale sheets of polarized nuclei positioned along the growth direction of the well. Applying rf voltages across the gates induces resonant spin transitions of selected isotopes. This depolarizing effect depends strongly on the separation of electrons and holes, suggesting that a highly localized mechanism accounts for the observed behavior.

Journal Article↗
PubMed2003

Suppressive effects of a selective inducible nitric oxide synthase (iNOS) inhibitor on pancreatic beta-cell dysfunction.

AIMS/HYPOTHESIS: Type 1 diabetes mellitus is an autoimmune disease characterized by dysfunction and destruction of the pancreatic beta cells. Interleukin-1beta (IL-1beta) has been reported to cause suppression of insulin secretion from pancreatic islets via induction of inducible nitric oxide synthase (iNOS) followed by nitric oxide (NO) production. In this study, we investigated the effects of inhibition of iNOS on pancreatic beta-cell dysfunction in non-obese diabetic (NOD) mice and IL-1beta-treated isolated rat pancreatic islets using a novel specific inhibitor, ONO-1714. METHODS: Female NOD mice which received subcutaneous infusion of ONO-1714 (4 microg/kg/day or 40 microg/kg/day) from 10 to 14 weeks after birth were compared with untreated NOD mice. In addition, pancreatic islets were isolated from Sprague-Dawley rats and cultured for 24 h with IL-1beta (100 U/mL) with or without ONO-1714 or the non-selective NOS inhibitor NG-monomethyl-L-arginine (L-NMMA). We measured insulin secretion and insulin content of the islets by ELISA, iNOS mRNA expression by reverse transcription-polymerase chain reaction, and NO generation by Griess Reagent System. RESULTS: Hyperglycaemia was observed in NOD mice. ONO-1714 treatment blunted this increase and tended to preserve insulin secretion, although body weight increase did not differ between the groups. Insulitis was also attenuated in the ONO-1714-administered group compared to the control group. Furthermore, in isolated rat pancreatic islets ONO-1714 prevented IL-1beta-induced inhibition of insulin secretion, this protection being evident in much lower concentrations than with L-NMMA. While ONO-1714 completely inhibited IL-1beta-induced NO production, it did not reduce expression of islet iNOS mRNA. CONCLUSION/INTERPRETATION: These findings indicate that ONO-1714 is promising as a therapeutic agent for autoimmune diabetes.

Amidines↗
PubMed2003

Gigahertz electron spin manipulation using voltage-controlled g-tensor modulation.

We present a scheme that enables gigahertz-bandwidth three-dimensional control of electron spins in a semiconductor heterostructure with the use of a single voltage signal. Microwave modulation of the Landé g tensor produces frequency-modulated electron spin precession. Driving at the Larmor frequency results in g-tensor modulation resonance, which is functionally equivalent to electron spin resonance but without the use of time-dependent magnetic fields. These results provide proof of the concept that quantum spin information can be locally manipulated with the use of high-speed electrical circuits.

Journal Article↗
PubMed2003

Functional electrical stimulation (FES) for spinal cord injury.

Restoration of respiratory motion by stimulation of the phrenic nerve was investigated. Respiratory motion was restored successfully by introducing a breathing pacemaker to a patient with respiratory disturbance due to upper cervical spinal cord injury. Breathing pacemakers are considered to be more similar to physiological conditions compared to mechanical ventilators. Although the system is very expensive, its cost effectiveness may be excellent, provided that it can be used for long hours each day over an extended period. The system is effective in improving patient QOL because it dramatically increases patient mobility. From these findings, it is concluded that breathing pacemakers should be used more frequently in Japan, and that various forms of support are necessary to cope with economic and other concerns.

Adult↗
PubMed2003

Expression of hypothalamic corticotropin-releasing hormone-like immunoreactivity in isolated ACTH deficiency: a report of an autopsied case.

A 77-yr-old man died of metastising adenocarcinoma of the lung. He had been treated with hydrocortisone for isolated ACTH deficiency for 9 yr. At autopsy, the pituitary and the adrenal glands were atrophic. Lymphocyte infiltration was not observed in the pituitary, the adrenal and the thyroid glands. Immunohistochemistry revealed selective loss of ACTH-like immunoreactivity in the pituitary gland whereas CRH-immunoreactive cells were found in the paraventricular nucleus of the hypothalamus. This is the first report demonstrating immunohistochemical examinations of the pituitary and the hypothalamus in isolated ACTH deficiency.

Adrenal Glands↗