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Biomedical subjects

M Handa

Publications and source records attributed to M Handa.

At least 55 records · Page 3Linked to original sources
PubMed2000

Genomic organization and expression of the mouse equilibrative, nitrobenzylthioinosine-sensitive nucleoside transporter 1 (ENT1) gene.

We have cloned and characterized the genomic structure of the mouse gene for the NBMPR-sensitive equilibrative nucleoside transporter (mENT1), which is located on chromosome 17C. About 12-kb of genomic DNA was sequenced including the promoter region, 12 exons, 11 introns, and the 3'-untranslated region. All exon-intron junction sequences conform to the GT/AG rule. Primer extension analysis demonstrated a transcription initiation site located 252 bp upstream of the translation start site. Analysis of the 2.5-kb 5'-flanking sequence shows putative binding sites for several transcription factors, including GATA-1, IRF-2, Pit-1, myogenin, CREB, Sp-1, Ap-2, MAZ, and GR. We demonstrated that mouse ENT1 mRNA was highly expressed in heart, spleen, lung, liver, and testis. Lower levels of expression were detected in brain and kidney. Functional analysis of the 5'-flanking region showed that the nucleotide sequence from -652 to -111 contains cis-regulatory elements that promote gene expression. We found two Sp-1 binding sites (-296/-303, -307/-313) and two MAZ binding sites (-353/-359, -522/-528) in this region. Luciferase assay results suggest that MAZ and Sp-1 transcription factors are important positive regulators of transcription for the ENT1 gene in NG108-15 cells.

3' Untranslated Regions↗
PubMed2000

Immunoneutralization of glycoprotein Ibalpha attenuates endotoxin-induced interactions of platelets and leukocytes with rat venular endothelium in vivo.

This study aimed to examine molecular mechanisms for endotoxin-induced adhesive changes in platelets in vivo. Platelets labeled with carboxyfluorescein diacetate succinimidyl ester were visualized in rat mesenteric venules through intravital microscopy assisted by a high-speed fluorescence video imager at 1000 frames per second or by a normal-speed intensifier under monitoring of erythrocyte velocity. Leukocyte rolling was examined by normal-speed transmission video images. The velocity of platelets traveling along the centerline of venules followed that of erythrocytes, whereas that measured at the periendothelial space was significantly smaller than the erythrocyte velocity; a majority of these cells exhibited transient but notable rolling with endothelium. Administration of endotoxin increased the density of periendothelial platelets and reduced the rolling velocities of platelets and leukocytes in venules: All events were attenuated by anti-rat P-selectin monoclonal antibody s789G or by anti-human glycoprotein (GP) Ibalpha monoclonal antibody GUR83/35, which blocks ristocetin-induced aggregation of rat platelets. Isolated rat platelets injected into endotoxin-pretreated rats were able to roll on the venules. This event was attenuated by pretreatment of platelets in vitro with GUR83/35 but not with s789G, suggesting involvement of endothelial P-selectin and platelet GP Ibalpha in the endotoxin-induced responses. Furthermore, isolated human platelets showed similar rolling interactions with endotoxin-preexposed rat venules, and pretreatment of the platelets with GUR83/35, but not with s789G, significantly reduced such interactions. Our results provide the first evidence for involvement of GP Ibalpha in endotoxin-induced microvascular rolling of platelets and leukocytes, and this system serves as a potentially useful tool to examine GP Ibalpha-associated function of human platelets in vivo.

Animals↗
PubMed2000

Targeting of liposomes carrying recombinant fragments of platelet membrane glycoprotein Ibalpha to immobilized von Willebrand factor under flow conditions.

Liposomes with covalently bound recombinant fragments of platelet membrane glycoprotein Ibalpha that retain the von Willebrand factor (vWf)-binding function (rGPIbalpha-liposomes) were prepared. Their interactions with an immobilized vWf surface under flow conditions were evaluated with a recirculating flow chamber, mounted on an epifluorescence microscope, which allows real-time visualization of fluorescence-labeled liposomes interacting with the surface. The interaction of rGPIbalpha-liposomes with the vWf surface was directly related to shear rate. At high densities of rGPIbalpha and vWf, rGPIbalpha-liposomes establishing contact with the vWf surface exhibited continuous displacement with decreased velocity relative to the hydrodynamic flow, depending on receptor density and matrix concentration. At lower densities of rGPIbalpha and vWf, rGPIbalpha-liposomes stopped only transiently, in the millisecond range, on the surface. This is the first study to demonstrate that the targeting of rGPIbalpha-liposomes is specific to the vWf surface under flow conditions.

Binding Sites↗
PubMed2000

Association between diabetic retinopathy and genetic variations in alpha2beta1 integrin, a platelet receptor for collagen.

Platelets might be involved in the pathogenesis of diabetic microangiopathy. Wide interindividual variations in the density of a platelet collagen receptor (alpha2beta1 integrin or glycoprotein Ia/IIa) are reportedly associated with polymorphism(s) in the gene encoding the alpha subunit of the receptor, including a Bgl II polymorphism in intron 7. The aim of the present study was to determine the relationship between the Bgl II polymorphism and the susceptibility to diabetic microangiopathy. A case-control study comparing 227 patients with type II diabetes mellitus (119 with versus 108 without diabetic retinopathy) as well as 169 nondiabetic subjects demonstrated that genotypes with Bgl II (+) allele had a significant increase in the risk for retinopathy. The odds ratio for Bgl II (+/+) to Bgl II (-/-) was 3.41 (95% CI, 1.49-7.78, P =.0036) when analysis was confined to those with a disease duration of diabetes of 10 years or more. The present study suggests that the presence of a Bg II (+) allele is a genetic risk factor for diabetic retinopathy. (Blood. 2000;95:1560-1564)

Alleles↗
PubMed2000

Rapid tyrosine phosphorylation and activation of Bruton's tyrosine/Tec kinases in platelets induced by collagen binding or CD32 cross-linking.

Stimulation of the platelet nonintegrin collagen receptor, glycoprotein VI, evokes a signaling response similar to that induced by antigen receptor activation in B and T lymphocytes. A key transducer of the lymphocyte signaling pathways is the Bruton's tyrosine kinase (Btk)/Tec kinase family, which connects receptors to the elevation of intracellular-free calcium levels. An important signaling function for Btk in collagen-induced platelet activation in vitro was recently demonstrated by other researchers using Btk-deficient platelets from patients with X-linked agammaglobulinemia (XLA). Since Btk-deficiency does not induce an overt platelet-based bleeding disorder in vivo, collagen receptor responses may include other Btk/Tec kinase family members in normal platelets. Both Btk and Tec had increased tyrosine following stimulation of collagen receptors or CD32 cross-linking. Data from kinetic analyses and inhibitor studies and the use of phosphopeptide-specific antibodies recognizing 2 Btk regulatory phosphorylated tyrosine residues suggest a mechanism for coordinate recruitment of Btk and Tec through the immunoreceptor tyrosine-based activation motif, Src family kinases, and phosphatidylinositol 3-kinase. In XLA platelets, collagen treatment increased tyrosine phosphorylation of Tec and several other signaling proteins, including Lyn, Fyb, Slp-76, and the Wiskott-Aldrich syndrome protein. This indicates that important elements of the collagen signaling pathway proximal and distal to Btk and Tec are preserved despite the lack of functional Btk. The results are consistent with the conclusion that activation of Tec may sustain XLA platelet function in vivo, while some in vitro assays of nonintegrin collagen receptor signaling through the Btk/Tec kinase family reflect the additive dosage of the transducers. (Blood. 2000;95:1663-1670)

Agammaglobulinaemia Tyrosine Kinase↗
PubMed2000

Osmium-metal coating device using hollow-cathode plasma CVD method.

A novel osmium-metal coating device for SEM observation has been developed to prevent negative charge build-up on specimens by applying the hollow-cathode low voltage discharge plasma chemical vapour deposition (CVD) method. The CVD method using the hollow-cathode offers the following advantages. (i) The method can deposit osmium-metal at very low discharge voltage that is as low as half of that of the planar parallel electrode method. Therefore, the method avoids damage due to ion bombardment during the coating process. (ii) The method can minimize the quantity of the OsO4 gas by introducing directly into the hollow-cathode. This feature is important to prevent the air pollution caused by the purged gas. (iii) A large coating area is guaranteed because the Os ion is filled in the hollow-cathode where the specimen is holed. (iv) The lower discharge voltage can be used by mixing Ar, N2 or air with the OsO4 gas as the environmental gas in the chamber. (v) The hybrid coating is also available by lining the appropriate metal material such as platinum (Pt) on the surface of the inside of the hollow-cathode. The method uses the plasma CVD of Os metal as well as the ion-sputter deposition of the lined metal.

Animals↗
PubMed2000

A new approach to antiplatelet therapy: inhibitor of GPIb/V/IX-vWF interaction.

Evidence has been presented that the interaction between von Willebrand factor (vWF) and its platelet membrane receptor, the GPIb/V/IX complex, plays an important role in the pathogenesis of arterial thrombosis. A monoclonal antibody against the A1 domain of vWF has been shown to inhibit thrombus formation in the animal model of arterial thrombosis. Based upon these findings, a new approach to treating arterial thrombosis has been proposed by intervening in the interaction between vWF and platelet.

Acetates↗
PubMed2000

[A case of right B2 hillar lung cancer treated by sleeve segmentectomy].

A 47-year-old male, a heavy smoker, was referred to our hospital after Class IV was detected by screening of sputum cytology. His chest X-ray film showed no abnormalities, but bronchoscopy revealed a small nodular lesion at the orifice of right B2. Squamous cell carcinoma was diagnosed by transbronchial biopsy. The clinical stage was I (T1N0M0), and S2 sleeve segmentectomy with lymph node dissection (R 2 b) was performed. The pathological stage was I (T1N0M0), and it was confirmed as early hilar lung cancer. There were no post operative complications and he is well without any evidence of recurrence 5 months after surgery. It may well be considered that this segmental bronchoplastic procedure is useful for cases with early stage squamous cell carcinoma of the segmental bronchus to preserve pulmonary function.

Carcinoma, Squamous Cell↗
PubMed2000

Platelet surface P-selectin molecules increased after exposing platelet to a high shear flow.

BACKGROUND: P-selectin is known to play a crucial role in leucocyte recruitment at sites of vascular injury. Although platelet surface expression of P-selectin molecules are well known to occur after platelet stimulation by chemical agonists such as alpha-thrombin, it is still uncertain whether P-selectin expression occurs in the process of the more physiological platelet activation pathway mediated by interaction between von Willebrand factor (vWF) and platelet receptor proteins, including glycoprotein (GP) Ibalpha and GP IIb/IIIa, occurring under high shear rates generated by blood flow. METHODS: We have developed a method to detect P-selectin molecules expressed on platelet surface with flow-cytometer and monoclonal antibody, which can bind exclusively to P-selectin (WGA1), directly conjugated with fluorescein isothiocynate. This method allowed us to measure platelet surface P-selectin molecules semiquantitatively. RESULTS: We demonstrated that a significant increase in platelet surface P-selectin molecules occur after exposing platelets to a relatively high shear rate of 10,800 s(-1). We have also demonstrated that shear-induced surface expression of P-selectin as well as microparticle release from platelets depended at least on the interaction between von Willebrand factor and glycoprotein Ibalpha, a platelet surface receptor for the former. CONCLUSIONS: Shear-induced von Willebrand-mediated surface expression of P-selectin may play a role in leucocyte recruitment in platelet thrombi at vascular injury sites.

Antibodies, Monoclonal↗
PubMed2000

A randomized trial of postoperative CDDP-based chemotherapy/chemoradiotherapy vs short-term immunochemotherapy in lung cancer.

BACKGROUND: Although a few reports indicated some benefit to survival, the effect of adjuvant therapy for the patients with resected lung cancer was still controversial. The aim of our study was to evaluate survival advantage of CDDP-based adjuvant therapy compared with short-term immunochemotherapy. METHODS EXPERIMENTAL DESIGN: prospective randomized trial. PATIENTS: from 1990 through 1994, 94 patients were registered. Forty-seven patients were randomly assigned to each group, i.e., CDDP-based therapy group (CB Group, CDDP+VDS+tegafur+OK-432 or CDDP+OK-432+mediastinal irradiation) or immunochemotherapy group (IC Group, tegafur+OK-432). PATIENTS in both groups were followed at 4-month intervals with the routine follow-up program of our department. RESULTS: No significant difference was observed between the patients' characteristics of two groups. Compliance of the regimen in each group was 79% in CB Group and 85% in IC Group. No treatment-related death was observed. Five-year survival rates of CB Group and IC Group were 49% and 51%, and 5-year disease-free survival rates were 46% and 44%, respectively. There were no statistical differences between the two groups. Furthermore, no survival differences could be found between CB Group and IC Group in any subgroup of patients. CONCLUSIONS: Both of these regimens were feasible. However, we have not observed any survival benefit in the CB Group in any subgroup, so far. Induction therapy, new chemotherapeutic agents, or anti-angiogenetic a agents may improve the survival of surgically treated lung cancer patients.

Adenocarcinoma↗
PubMed1999

Phosphatidylinositol 3-kinase is involved in the protection of primary cultured human erythroid precursor cells from apoptosis.

Little is known about the physiologic role of phosphatidylinositol 3-kinase (PI-3K) in the development of erythrocytes. Previous studies have shown that the effects of the PI-3K inhibitor wortmannin on erythropoietin (EPO)-dependent cell lines differed depending on the cell type used. Wortmannin inhibited EPO-induced differentiation of some cell lines without affecting their proliferation; however, the EPO-induced proliferation of other cell lines was inhibited by wortmannin. In neither case were signs of apoptosis observed. We have previously reported that signaling in highly purified human colony forming units-erythroid (CFU-E), generated in vitro from CD34(+) cells, differed from that in EPO-dependent cell lines. In the current study, we examined the effects of a more specific PI-3K inhibitor (LY294002) on human CFU-E. We found that LY294002 dose-dependently inhibits the proliferation of erythroid progenitor cells with a half-maximal effect at 10 micromol/L LY294002. LY294002 at similar concentrations also induces apoptosis of these cells, as evidenced by the appearance of annexin V-binding cells and DNA fragmentation. The steady-state phosphorylation of AKT at Ser-473 that occurs as a result of PI-3K activation was also inhibited by LY294002 at similar concentrations, suggesting that the effects of LY294002 are specific. Interestingly, the acceleration of apoptosis by LY294002 was observed in the presence or absence of EPO. Further, deprivation of EPO resulted in accelerated apoptosis irrespective of the presence of LY294002. Our study confirms and extends the finding that signaling in human primary cultured erythroid cells is significantly different from that in EPO-dependent cell lines. These data suggest that PI-3K has an antiapoptotic role in erythroid progenitor cells. In addition, 2 different pathways for the protection of primary erythroid cells from apoptosis likely exist: 1 independent of EPO that is LY294002-sensitive and one that is EPO-dependent and at least partly insensitive to LY294002.

Androstadienes↗
PubMed1999

A mutation in the extracellular cysteine-rich repeat region of the beta3 subunit activates integrins alphaIIbbeta3 and alphaVbeta3.

Inside-out signaling regulates the ligand-binding function of integrins through changes in receptor affinity and/or avidity. For example, alphaIIbbeta3 is in a low-affinity/avidity state in resting platelets, and activation of the receptor by platelet agonists enables fibrinogen to bind. In addition, certain mutations and truncations of the integrin cytoplasmic tails are associated with a high-affinity/avidity receptor. To further evaluate the structural basis of integrin activation, stable Chinese hamster ovary (CHO) cell transfectants were screened for high-affinity/avidity variants of alphaIIbbeta3. One clone (AM-1) expressed constitutively active alphaIIbbeta3, as evidenced by (1) binding of soluble fibrinogen and PAC1, a ligand-mimetic antialphaIIbbeta3 antibody; and (2) fibrinogen-dependent cell aggregation. Sequence analysis and mutant expression in 293 cells proved that a single amino acid substitution in the cysteine-rich, extracellular portion of beta3(T562N) was responsible for receptor activation. In fact, T562N also activated alphaVbeta3, leading to spontaneous binding of soluble fibrinogen to 293 cells. In contrast, neither T562A nor T562Q activated alphaIIbbeta3, suggesting that acquisition of asparagine at residue 562 was the relevant variable. T562N also led to aberrant glycosylation of beta3, but this was not responsible for the receptor activation. The binding of soluble fibrinogen to alphaIIbbeta3(T562N) was not sufficient to trigger tyrosine phosphorylation of pp125(FAK), indicating that additional post-ligand binding events are required to activate this protein tyrosine kinase during integrin signaling. These studies have uncovered a novel gain-of-function mutation in a region of beta3 intermediate between the ligand-binding region and the cytoplasmic tail, and they suggest that this region is involved in integrin structural changes during inside-out signaling.

Amino Acid Substitution↗
PubMed1999

Serum KL-6, a novel mucin-like glycoprotein, as an indicator of interstitial pneumonitis following lobectomy.

Serum KL-6 has been shown to be a useful marker of active interstitial pneumonitis in patients who have not undergone lobectomy. Considering that KL-6 is produced mainly in the distal airway epithelium, the present study was conducted to determine whether resected lung volume influenced the postoperative KL-6 levels, and also to evaluate whether it is a useful parameter in patients who have undergone lobectomy. The serum KL-6 levels decreased by 36% 1 week after lobectomy, but returned to the preoperative levels by 2 months postoperatively. Although the KL-6 levels increased by 100% 3 to 4 months after lobectomy, the levels were significantly lower than those in interstitial pneumonitis (P < 0.05). The decrease in the KL-6 levels correlated with the number of resected lung segments, but not with the changes in white blood cell count, lactate dehydrogenase level, or C-reactive protein level. In comparison with the lobectomy patients, the serum KL-6 levels decreased by half in patients who had undergone partial resection (P < 0.05). The results of this study suggest that the serum KL-6 level may be a useful indicator of interstitial pneumonitis after lobectomy. Serum KL-6 levels are influenced by the volume of the resected lung, and probably also by the upregulation of KL-6 production.

Adolescent↗
PubMed1999

Functional evaluations for pulmonary resection for lung cancer in octogenarians. Investigation from postoperative complications.

We have reviewed the records of our twenty-four patients aged 80 years or older who underwent lung resections for bronchogenic carcinoma between 1983 and 1997 in our department. Eighteen patients were male and six were female. Adenocarcinoma was the histology in more than half of the cases (13 patients), along with 8 squamous cell carcinoma, 2 large cell carcinoma, and one small cell lung carcinoma. More than single lobectomy was performed in each patient. Unilateral pulmonary occlusion tests were employed in patients with impairment in pulmonary functions. Every patient, who underwent the unilateral pulmonary occlusion test, was certified that the total pulmonary vascular resistance index during unilateral pulmonary arterial occlusion test was less than 700 dyne.sec.cm-5.m2. Postoperative cardiovascular complications, such as paroxysmal atrial tachycardia, premature atrial contraction, premature ventricular contraction or atrial fibrillation, were seen in 10 patients. Postoperative respiratory complications, namely, sputa retention, retained secretions or atelectasis, were seen in 7 patients. The extent of dissection of mediastinal lymph node was not correlated to the postoperative pulmonary complications. However, the incidence of arrhythmias in the patients who received R2 mediastinal lymphnode dissection was much higher than in those who received R1 or R0 dissection. Complete blood counts and serum biochemical analysis performed at about three weeks after operations revealed leukocytosis and increases in levels of serum transaminase. These phenomena in leukocytosis and increases in the levels of serum transaminase in these patients were similar to those in younger patients. There was no operative death. We conclude that some patients over 80 years are candidates for lung resection after careful preoperative cardiopulmonary evaluation.

Adenocarcinoma↗
PubMed1999

Esophageal motility and psychiatric factors in functional dyspepsia patients with or without pain.

Subtypes of functional dyspepsia (FD), including refluxlike dyspepsia, ulcerlike dyspepsia, dysmotility-like dyspepsia, and nonspecific dyspepsia, have been described and are widely used clinically. However, these symptom patterns often overlap, and the terms are insufficient for indicating all FD symptoms. In this study, we divided 71 FD patients into two groups: patients with or without pain. Group I, the pain dyspepsia group, included patients in whom the main symptoms were epigastralgia and/or chest pain. Group II, the painless dyspepsia group, included patients without pain, in whom the symptoms were nausea, vomiting, and heartburn. We examined the relationship between esophageal function and psychiatric factors in the test groups and compared them with a control group. Of the FD patients, 19.7% [8 (25%) of 32 group I patients, 6 (15.4%) of 39 group II patients] had esophageal motility disorders, such as nutcracker esophagus and diffuse esophageal spasm. The LES pressure of group I was higher than that of group II by esophageal manometry (P < 0.05). In 17 (53.1%) of 32 group I patients and 31 (79.5%) of 39 group II patients, psychiatric disorders (38.0% had depressive disorder and 21.1% had an anxiety disorder) were diagnosed following DSM III-R criteria. Group II tended to be more depressive than group I (P = 0.0508). Psychological assessment scores, STAI-I and STAI-II, were higher in groups I and II than in the control group (P < 0.001). Long-term distress, anxiety, and depression seem to influence the symptoms of FD patients. Esophageal dysmotility may be an important functional abnormality of FD.

Abdominal Pain↗
PubMed1999

Antidepressant treatment of patients with diffuse esophageal spasm: a psychosomatic approach.

The cause of diffuse esophageal spasm (DES) has not been clearly established, and effective treatment is lacking. To determine whether a psychosomatic approach can be effective in treating DES patients, nine patients and 26 healthy volunteers were studied. Esophageal manometry and psychological testing were performed in both groups. The psychological background of the DES patients was investigated. Psychiatric diagnoses were made according to the criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised. The authors started psychosomatic treatment with isosorbide dinitrate for 1 month, then prescribed serotonin reuptake inhibitor antidepressants for an additional month. Anxiety and depression scores were substantially higher for the DES group than for the control group. Five of the nine DES patients (56%) were diagnosed as having major psychiatric disorders. Only one patient showed improvement with isosorbide dinitrate, and eight patients improved with antidepressants. These initial observations suggest that psychosomatic treatment with antidepressants may be effective in the treatment of DES.

Adult↗
PubMed1999

[Experience with surgery for congenital esophago-bronchial fistula with esophageal diverticulum in adult].

A 65-year-old female was admitted into our department with complaint of bloody sputum. An upper G-I series examinations and thoracic CT demonstrated an esophago-bronchial fistula with diverticulum located between the mid-esophagus and right B6. Following postero-lateral thoracostomy, the fistula was surgically removed and right lower lobectomy was carried out. No inflammatory changes were found in the surrounding tissues of the fistula and the diverticulum. Histological examination revealed that the fistula wall contained squamous epithelium and muscularis mucosa. These results suggested that this case was congenital esophago-bronchial fistula categorized as Braimbridge type I.

Aged↗