Search PubMed⌕ Search

Biomedical subjects

T Yoshikawa

Publications and source records attributed to T Yoshikawa.

At least 235 records · Page 13Linked to original sources
PubMed2000

Vitamin E and leukocyte-endothelial cell interactions.

Leukocyte-endothelial cell interactions are mediated by adhesion molecules, expression of which is modulated by cytokines and chemical mediators in the early phase of inflammatory and immunologic reactions, including the development of atherosclerosis. Vitamin E is a lipid-soluble antioxidant that is present in all cell membranes at a low concentration and is reported to be an anti-atherogenic agent. Recently, it was reported that vitamin E inhibits the activation of protein kinase C and nuclear factor-kappa B (NF-kappa B). We demonstrated that vitamin E can prevent leukocyte-endothelial cell adhesion by inhibiting signal transduction involved in the surface expression of adhesion molecules by leukocytes and endothelial cells. These results suggest that vitamin E may have a protective effect against the progression of inflammation and atherosclerosis.

Animals↗
PubMed2000

Lung cancer implantation in the chest wall following percutaneous fine needle aspiration biopsy.

We describe a 70-year-old man with lung cancer implantation in the chest wall following percutaneous fine needle aspiration biopsy. He underwent lobectomy after percutaneous transthoracic fine needle aspiration biopsy using a 19-gauge needle. Twenty-six months after the biopsy, he noticed a hard subcutaneous tumor at the biopsy site in the chest wall. Ribs and intercostal muscles were resected. The primary lung tumor and the chest wall tumor were histologically identical, but were not contiguous to each other. We concluded that the subcutaneous tumor was due to needle biopsy implantation. This complication is extremely rare, but open biopsy should always be considered as a possible alternative. During the procedure, care must be taken with the least chance of implantation and patients should be observed carefully after needle biopsy.

Adenocarcinoma↗
PubMed2000

Do plasma and urine trypsinogen activation peptides (TAP) really increase in trypsin-taurocholate-induced pancreatitis?

Plasma and urine levels of trypsinogen activation peptides (TAP) reflect the severity of acute pancreatitis in experimental and clinical acute pancreatitis. In trypsin-taurocholate-induced pancreatitis in rats, the extrinsic bovine trypsin used for the induction of pancreatitis might influence on the TAP levels after induction of pancreatitis. The aim of the present study was to elucidate whether infused trypsin itself affects TAP levels in trypsin-taurocholate-induced pancreatitis. Rats were divided into three groups. In the pancreatitis group, acute pancreatitis was induced by a retrograde infusion of bovine trypsin and sodium taurocholate into the pancreatic duct. In the duct infusion group and peritoneal injection group, a mixture of bovine trypsin and trypsin inhibitor, ONO-3403, was infused into the pancreatic duct or the peritoneal cavity. Plasma and urine TAP concentration significantly increased in trypsin-taurocholate-induced pancreatitis but not in the duct infusion and peritoneal injection groups for 6 hours after the infusion of trypsin. Serum rat immunoreactive trypsin (IRT) and amylase significantly increased in the pancreatitis and duct infusion groups but not in the peritoneal injection group. Serum levels of bovine IRT in the pancreatitis group was significantly lower than those in duct infusion and peritoneal injection groups. In conclusion, an intraductal infusion of bovine trypsin itself into pancreatic duct does not influence the levels of plasma and urine TAP in trypsin-taurocholate-induced pancreatitis.

Acute Disease↗
PubMed2000

Clinical characteristics of febrile convulsions during primary HHV-6 infection.

OBJECTIVE: To clarify clinical characteristics of children with febrile convulsions during primary human herpesvirus 6 (HHV-6) infection. SUBJECTS AND METHODS: The clinical characteristics of first febrile convulsion were compared between those with and without primary HHV-6 infection in 105 children. HHV-6 infection was verified by culture or acute/convalescent anti-HHV-6 antibody titres. RESULTS: Primary infection with HHV-6 was seen in 21 of 105 patients with febrile convulsions (3 upper respiratory infection, 1 lower respiratory infection, and 17 exanthem subitum). 13 of 23 patients < 1 year, 19 of 79 patients with first febrile convulsion, and 2 of 15 with second convulsion were infected with HHV-6. The median age of patients with first febrile convulsion and HHV-6 was significantly lower than those without infection. The frequency of clustering seizures, long lasting seizures, partial seizures, and postictal paralysis was significantly higher among those with primary HHV-6 infection than among those without. The frequency of atypical seizures in 19 patients with first febrile convulsion associated with primary infection was significantly higher than in 60 patients without primary infection. The frequency in infants younger than 1 year of age was also significantly higher than that in 10 age matched infants without primary infection. CONCLUSIONS: These findings suggest that primary infection with HHV-6 is frequently associated with febrile convulsions in infants and young children and that it often results in the development of a more severe form of convulsions, such as partial seizures, prolonged seizures, and repeated seizures, and might be a risk factor for subsequent development of epilepsy.

Age Distribution↗
PubMed2000

Invasion by human herpesvirus 6 and human herpesvirus 7 of the central nervous system in patients with neurological signs and symptoms.

METHODS: A total of 43 children with neurological signs and symptoms were enrolled in the study. All children were suspected of having meningitis, and lumbar punctures were performed. Human herpesvirus 6 (HHV-6) and HHV-7 DNA was detected in cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) by nested polymerase chain reaction. RESULTS: Most patients had detectable serum antibody to both HHV6 and 7. HHV6 DNA was detected in PBMC of 15 patients and in CSF cell pellet of seven. Corresponding figures for HHV7 were 28 and 6.2/7, and 5/6 with CSF viral DNA also had it in PBMC, respectively. No viral DNA was detected in CSF supernatants. The seven HHV6 CSF viruses were all variant B. CONCLUSION: These data suggest that HHV-7 may invade the CNS.

Child↗
PubMed2000

Immune response to gangliosides in a case of Guillain-Barré syndrome after varicella.

An 8 year old girl was admitted to hospital with the typical clinical features of Guillain-Barré syndrome (GBS) after recovering from varicella. Onset of the disease was just two weeks after the onset of varicella in her young sister. Examination of cerebrospinal fluid and nerve conduction studies showed typical findings of GBS. Although serum from both the patient and sister were analysed for autoantibodies to gangliosides and myelin P0 protein, IgM anti-GM1 antibody and anti-GD1b antibody were only detected in the patient. HLA DR haplotypes were quite different between the two subjects. This suggests that these autoantibodies may play an important role in the pathogenesis of GBS after varicella zoster virus infection.

Autoantibodies↗
PubMed2000

Possible paracrine growth of adenocarcinoma of the stomach induced by granulocyte colony stimulating factor produced by squamous cell carcinoma of the oesophagus.

Synchronous cancers of the oesophagus and stomach diagnosed in a patient showing pronounced leucocytosis were examined for production of granulocyte colony stimulating factor (G-CSF) and expression of G-CSF receptor. Whereas enzyme immunoassay of tissue extracts showed that the oesophageal carcinoma produced G-CSF, the gastric cancer did not. However, the gastric tumour showed G-CSF receptor expression on immunohistochemical examination of sections. These findings suggest that the oesophageal cancer promoted gastric cancer growth by paracrine mechanisms involving G-CSF.

Adenocarcinoma↗
PubMed2000

Suppression of specific IgE antibody responses by liposome-conjugated ovalbumin in mice sensitized with ovalbumin via the respiratory tract.

BACKGROUND: Previously we have shown that intranasal administration of ovalbumin (OVA) together with cholera toxin (CT) abrogates nasal tolerance to OVA, resulting in the induction of specific IgE antibody (Ab) responses, and that intraperitoneal injection of OVA coupled with liposomes (OVA-liposomes) induces a selective suppression of IgE Ab responses to OVA. Whether OVA-liposomes suppress anti-OVA IgE Ab responses in mice sensitized with CT-combined OVA via the respiratory tract remains to be clarified. METHODS: In some experiments, mice were given OVA, liposomes or OVA-liposomes with or without CT intranasally three times, at 2-week intervals (weeks 0, 2 and 4). In other experiments, mice were given OVA-liposomes intranasally 2 days before or 1 and 3 weeks after CT-combined OVA (week 0), which was administered intranasally three times, at 2-week intervals (weeks 0, 2 and 4). Two weeks after the third administration of CT-combined OVA (week 0), nasal wash and serum IgA, IgG and IgE Ab responses were assayed. RESULTS: Pretreatment with OVA-liposomes suppressed IgE Ab responses to CT-combined OVA, with a significantly high production of both nasal IgA and serum IgG Abs. Moreover, treatment with OVA-liposomes 1 and 3 weeks after CT-combined OVA administration also suppressed IgE Ab responses. The suppression of anti-OVA IgE Ab production by OVA-liposomes was accompanied by a simultaneous enhancement of specific IgA and IgG (IgG1, and especially IgG2a) Ab production. CONCLUSIONS: Postimmunization treatment with OVA-liposomes, as well as preimmunization treatment, suppressed specific IgE Ab responses in mice sensitized intranasally with CT-combined OVA. Allergens conjugated to liposomes may be appropriate for preventing the development of allergies to inhaled or dietary antigens in humans.

Administration, Intranasal↗
PubMed2000

The effect of previous administration of nizatidine on the neuromuscular effects of vecuronium and the effect of nizatidine on gastric secretion.

Nizatidine, a new H2-receptor antagonist, has been reported to inhibit acetylcholinesterase activity. This could lead to an interaction with neuromuscular blocking drugs. This study examined the effects of nizatidine on the actions of vecuronium. Oral nizatidine has been reported to be an effective protective agent against acid aspiration syndrome, and we reevaluated this effect. The control group (n = 10) received a placebo with water 50 ml and the nizatidine group (n = 10) received nizatidine 300 mg with water 50 ml two hours before arrival in the operating room. Gastric contents were aspirated and the volume and pH measured before induction of anaesthesia. Anaesthesia was induced in all patients with thiopentone 5 mg/kg and 1.5% isoflurane in 98.5% oxygen followed by vecuronium 0.1 mg/kg. Vecuronium onset time and duration time 25 (time from injection until recovery of 25% of vaseline twitch amplitude) were obtained using electromyography. There were no significant differences between the two groups in vecuronium onset time or duration time 25. Gastric fluid volume was greater and gastric pH was lower in the control group than in the nizatidine group. 70% of the control group and none of the nizatidine group (P < 0.005) had a gastric content pH < 2.5 or volume > 25 ml.

Elective Surgical Procedures↗
PubMed2000

Facile synthesis of a chitosan hybrid of a laminin-related peptide and its antimetastatic effect in mice.

Laminin, a cell adhesion protein, consists of three peptide chains (alpha-1, beta-1 and gamma-1). The beta-1 chain contains a Tyr-Ile-Gly-Ser-Arg (YIGSR) sequence that has been found to inhibit experimental metastasis in mice. We have prepared a hybrid of a water-soluble chitosan and a laminin-related peptide, and have examined its inhibitory effect on experimental metastasis in mice. A laminin-related peptide, acetyl-Tyr-Ile-Gly-Ser-Arg-betaAla-OH (Ac-YIGSRbetaA-OH), was prepared by a solid-phase method. Ac-YIGSRbetaA-OH was then reacted with a water-soluble chitosan. BetaAla is a spacer and was placed to avoid racemization of the Arg residue when the peptide was coupled with chitosan. Although chitosan has amino groups, they did not react with the peptide. Four methods were tried to achieve a coupling reaction, the diphenylphosphoryl azide method, the diisopropylcarbodiimide/1-hydroxybenzotriazole method, the water-soluble carbodiimide (WSC), and the 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) method, but all four methods were unsuccessful. Therefore, a small spacer, tert-butyloxycarbonyl-Gly, was intercalated in chitosan, by the TBTU method, to facilitate its coupling with the peptide. After removal of the protecting group, the Gly-chitosan was coupled with Ac-YIGSRbetaA-OH by the water-soluble carbodiimide method to give Ac-YIGSRbetaAG-chitosan. Conjugation of the peptide with the larger chitosan molecule did not reduce the inhibitory effect of the peptide on experimental metastasis in mice, it actually potentiated the antimetastatic effect, demonstrating that chitosan may be effective as a drug carrier for peptides.

Animals↗
PubMed2000

Effects of a nitric oxide synthase inhibitor on hypophagia induced by the peripheral 5-HT receptor agonists, alpha-methyl-5-hydroxytryptamine and 5-carboxamidotryptamine in rats.

We investigated the effects of the nitric oxide (NO) synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME) on hypophagia in rats elicited by alpha-methyl-5-hydroxytryptamine (alpha-methyl-5-HT) and 5-carboxamidotryptamine (5-CT) which are suggested to be mediated by the peripheral 5-HT2A and 5-HT7 receptor, respectively. Both alpha-methyl-5-HT and 5-CT apparently inhibited food intake in food-deprived rats. L-NAME significantly enhanced alpha-methyl-5-HT-elicited hypophagia, while it inhibited 5-CT-elicited hypophagia. These results suggest that NO is differentially related to alpha-methyl-5-HT and 5-CT-induced hypophagia and that NO may play a role in hypo- and hyperphagia.

Animals↗
PubMed2000

Age-adjusted heart rate variability as an index of the severity and prognosis of heart failure.

The age-adjusted, heart rate variability (HRV) was evaluated as a parameter for the severity of heart failure and its prognosis. HRV was obtained by 24-h Holter monitoring in patients with left ventricular dysfunction (LVD). New York Heart Association (NYHA) functional classification, echocardiography, radioisotope ventriculography, and blood examination were performed, and compared between patients and normal subjects. The evaluation was repeated during the follow-up period. Finally, using the lower limit of HRV, patients were divided into either normal or abnormal group for each low-frequency power (LF) and high-frequency power (HF) (age-adjusted HRV). Other parameters of heart failure and prognosis were compared between these 2 groups. HRV tended to be lower in patients with LVD. HF decreased at the early stage of heart failure, but did not decrease progressively. LF decreased progressively. HRV change paralleled the change of NYHA. The abnormal HRV group showed a poor prognosis for cardiac death, but not for sudden cardiac death. In patients with LVD, HRV was decreased compared with the normal subjects. Change in HRV correlated with the change in NYHA classification. Age-adjusted HRV correlated with cardiac-death prognosis, but not for sudden cardiac death.

Aged↗
PubMed2000

Ultrastructural study of Langerhans cells in equine insect hypersensitivity "Kasen".

Ultrastructural features of Langerhans cells (LCs) of equine "Kasen" were studied. Electron microscopic observation revealed that LCs were dendritic and had irregular nuclear membranes. A number of Birbeck granules (Bgs) of various types were observed in the cytoplasm of LCs. In LCs in the upper stratum spinous, many Bgs were observed (Type 2 LC). LCs in the epidermo-dermal junction (EDJ) had a few Bgs, vesicles (multivesicular bodies) and highly electron-dense granular endosomes in the cytoplasm (Type 3 LC). Inactive LCs were also observed between the keratinocytes (Type 1 LC). Various types of LCs observed in the skin lesions of equine "Kasen" were interpreted as representing those that recognize, intake and process antigens.

Animals↗
PubMed2000

The kinetics of Langerhans cells in equine insect hypersensitivity "Kasen".

An immunohistochemical study was carried out on the kinetics of Langerhans cells (LCs) at various pathological stages of "Kasen". Skin lesions of "Kasen" that were collected by biopsy from May to October were classified histopathologically into three stages: initial (Group I, 31 cases), developing (Group II, 50 cases) and regressing (Group III, 13 cases). LCs showed a positive reaction with anti-equine thymocytes (EqT6) monoclonal antibody (MoAb) and anti-major histocompatibility complex (MHC) class II MoAb by immunohistochemical staining. The anti-EqT6 MoAb was intensely positive along the cytoplasmic process. The number of LCs per unit area increased markedly with the passage of time from the initial to the developing stage of the disease, particularly in the epidermo-dermal junction (EDJ). However, the number of LCs tended to decrease in the epidermal layer. In conclusion, the LCs moving into the epidermal layer moved into the EDJ and dermis during the time course of lesion development, and the changes occurring in LCs possibly influenced the progression of the skin lesions of "Kasen".

Animals↗
PubMed2000

In vivo osteogenic capability of cultured allogeneic bone in porous hydroxyapatite: immunosuppressive and osteogenic potential of FK506 in vivo.

Fischer or ACI rat marrow cells were obtained from femoral shafts and were cultured to confluence in Eagle's minimal essential medium (EMEM) supplemented with 15% fetal bovine serum. After trypsinization, the cells were subcultured on porous hydroxyapatite (HA; Interpore 500) blocks in the presence of beta-glycerophosphate and 10 nM dexamethasone (Dex). After 2 weeks of subculture, a mineralized bone matrix with osteogenic cells developed on the HA pore surfaces. ACI or Fischer cultured bone tissue/HA constructs were implanted subcutaneously into the backs of Fischer rats and the immunosuppressant FK506 was given to the rats for 4 weeks. Implants were harvested 4 weeks and 8 weeks after insertion. At 4 weeks, the ACI constructs (allografts) showed high levels of osteogenic parameters (alkaline phosphatase [ALP] activity and osteocalcin content) and bone formation was observed together with active osteoblasts without obvious accumulation of inflammatory cells. At 8 weeks, active osteoblasts and progressive bone formation were still observed, while osteogenic parameters remained high and osteocalcin messenger RNA (mRNA) was detected. Without FK506 administration, the allografts showed neither bone formation nor osteocalcin mRNA and there were only trace levels of the osteogenic parameters. In the case of Fischer constructs (isografts), extensive bone formation was detected and all the osteogenic parameters were higher with FK506 than without FK506 at both 4 weeks and 8 weeks. These results indicate that cultured bone tissue/HA constructs possess a high osteogenic potential, even as allografts, and that FK506 not only has an immunosuppressive action, but also promotes bone formation.

Alkaline Phosphatase↗
PubMed2000

Increased osteocyte apoptosis during the development of femoral head osteonecrosis in spontaneously hypertensive rats.

We investigated the presence of osteocyte apoptosis in the necrotic trabeculae of the femoral head of spontaneously hypertensive rat (SHR) using the in situ nick end labeling (TUNEL) method and transmission electron microscopy. The occurrence of osteonecrosis and ossification disturbance was significantly higher in SHR compared with Wistar Kyoto (WKY) rats, and Wistar (WT) rats used as control animals (P < 0.01). A high population of TUNEL positive osteocytes was detected mainly in 10- and 15-week-old SHRs. Sectioned examination of the femoral head of SHRs and WKY rats by electron microscopy revealed apoptotic cell appearances such as aggregation of chromatin particles and lipid formation. In contrast, a positive reaction was significantly lower in osteocytes in the femoral heads of WT rats (P < 0.01). Our results indicate that apoptosis forms an important component of the global pathologic process affecting the femoral head of SHR, which leads to osteonecrosis in this region.

Animals↗
PubMed2000

Langerhans cell histiocytosis limited to the pituitary-hypothalamic axis--two case reports.

Langerhans cell histiocytosis rarely presents as a solitary lesion in the pituitary-hypothalamic region, and is indistinguishable from germinoma, which occurs much more frequently, especially in Japanese. A 14-year-old girl and a 9-year-old girl presented with polydipsia and polyuria as the initial symptoms. Magnetic resonance (MR) imaging demonstrated a round mass at the pituitary stalk appearing as isointense on T1-weighted imaging and hyperintense on T2-weighted imaging. Endocrinological examination revealed mild hypopituitarism with central diabetes insipidus. Both patients underwent open craniotomy. Histological examination revealed granulomatous tissue with eosinophil infiltration and frequent Langerhans histiocyte clustering, compatible with the diagnosis of Langerhans cell histiocytosis. Low-dose local irradiation of 20 Gy was administered. First patient was followed up for 8 years, and her hypopituitarism gradually improved to a minimal level with only amenorrhea as the residual symptom. Recent MR imaging showed no residual mass at the region. Second patient was followed up for 15 months, and her diabetes insipidus is stable. MR imaging performed 5 months after the treatment showed marked reduction of the mass. These cases reemphasize the importance of histological diagnosis for lesions with similar neuroimaging appearances. Biopsy and low-dose irradiation are an effective treatment for this rare and essentially benign lesion, as opposed to attempting total removal of the mass.

Adolescent↗