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Biomedical subjects

Y Haga

Publications and source records attributed to Y Haga.

At least 19 recordsLinked to original sources
PubMed2003

Coexistence of antiferromagnetism and superconductivity near the quantum criticality of the heavy-fermion compound CeRhIn5.

We report a study on the interplay between antiferromagnetism (AFM) and superconductivity (SC) in a heavy-fermion compound CeRhIn5 under pressure P=1.75 GPa. The onset of the magnetic order is evidenced from a clear split of 115In nuclear quadrupole resonance spectrum due to the spontaneous internal field below the Néel temperature T(N)=2.5 K. Simultaneously, bulk SC below T(c)=2.0 K is demonstrated by the observation of the Meissner diamagnetism signal whose size is the same as in the exclusively superconducting phase. These results indicate that the AFM coexists homogeneously with the SC at a microscopic level.

Journal Article↗
PubMed2003

[Showing no increase of C-reactive protein and developing non-bacterial median chest wound dehiscence after coronary artery bypass grafting].

A 72-year-old male underwent coronary artery bypass grafting for 3 vessels disease. After the operation, the peak C-reactive protein (CRP) level was 0.85 mg/dl and CRP levels stayed very low. Forty days after the operation the patient developed a progressive median chest wound dehiscence but the bacterial cultures were negative. In spite of conventional therapies such as debridement of necrotic tissue or irrigation, the wound granulation was underdeveloped. After 6 months an epidermis had developed to cover the wound.

Aged↗
PubMed2002

Magnetic structure, phase diagram, and a new type of spin-flop transition dominated by higher order interaction in a localized 5f system U3Pd20Si6.

The magnetic structure of the localized-5f uranium intermetallic compound U3Pd20Si6 has been determined by means of a neutron diffraction experiment. Our data demonstrate that this compound has a collinear coupling of the sublattice ordering of the uranium spins on the 4a and 8c sites. We conclude that higher-order exchange and/or quadrupole interactions are necessary to stabilize this unique collinear structure. We discovered a new type of spin-flop transition against the uniaxial anisotropy induced by this collinear coupling.

Journal Article↗
PubMed2001

Adjuvant chemotherapy for large cell carcinoma with neuroendocrine features.

BACKGROUND: In 1999, the World Health Organization categorized large cell neuroendocrine carcinoma, large cell carcinoma with neuroendocrine differentiation, and large cell carcinoma with neuroendocrine morphology as a variant of large cell carcinoma. Patients with large cell carcinoma with neuroendocrine features have poor prognoses, comparable to those for small cell lung carcinoma. Small cell lung carcinoma is sensitive to chemotherapy; however, it is still unclear whether large cell carcinoma with neuroendocrine features is responsive to adjuvant chemotherapy. METHODS: The authors analyzed 73 patients with large cell carcinoma with neuroendocrine features who underwent resection of the tumor and studied the effect of adjuvant chemotherapy for large cell carcinoma with neuroendocrine features. RESULTS: In patients with Stage I disease, the overall survival for patients with adjuvant chemotherapy based on cisplatin, carboplatin, or cyclophosphamide, which were used as standard chemotherapy for small cell lung carcinoma, were significantly higher than the overall survival for patients without adjuvant chemotherapy. In patients with Stage II, III, and IV disease, there was no significant difference between patients with adjuvant chemotherapy and without adjuvant chemotherapy. CONCLUSIONS: Adjuvant chemotherapy based on cisplatin, carboplatin, or cyclophosphamide prolongs survival of patients with large cell carcinoma with neuroendocrine features in early stage.

Adult↗
PubMed2001

Clinical characterization of pulmonary large cell neuroendocrine carcinoma and large cell carcinoma with neuroendocrine morphology.

BACKGROUND: Large cell carcinoma has been classified as four potential types based on its neuroendocrine morphology and evidence of neuroendocrine differentiation discernible by immunohistochemistry or electron microscopy. However, the clinical relation among these four categories has not been clearly defined. In 1999, the World Health Organization (WHO) categorized large cell neuroendocrine carcinoma as a variant of large cell carcinoma. MATERIAL AND METHODS The authors analyzed 119 cases of large cell carcinoma from a total of 2070 primary lung carcinoma cases resected surgically between 1969-1999. Using light microscopy, electron microscopy, and immunohistochemical staining, the authors reclassified these cases into large cell neuroendocrine carcinoma (LCNEC), large cell carcinoma with neuroendocrine differentiation (LCCND), large cell carcinoma with neuroendocrine morphology (LCCNM), and classic large cell carcinoma (CLCC). RESULTS: In multivariate analyses, the authors found that large cell carcinoma with neuroendocrine features, which combined LCNEC, LCCND, and LCCNM, impacted both the overall survival and disease-free survival of patients. The clinical behavior of LCCNM was similar to that of LCNEC. CONCLUSIONS: Large cell carcinomas with neuroendocrine features appear to be more clinically aggressive than CLCCs. The authors' findings suggest that the histologic identification of neuroendocrine features in tumor tissue from patients diagnosed with large cell carcinoma of the lung may have clinical relevance.

Adult↗
PubMed2001

Unique spin dynamics and unconventional superconductivity in the layered heavy fermion compound CeIrIn5: NQR evidence.

We report measurements of the 115In nuclear spin-lattice relaxation rate ( 1/T1) between T = 0.09 and 100 K in the new heavy fermion (HF) compound CeIrIn5. At 0.4 < or = T< or = 100 K, 1/T1 is strongly T-dependent, which indicates that CeIrIn5 is much more itinerant than known Ce-based HFs. We find that 1/T1T, subtracting that for LaIrIn5, follows a (1 / T+straight theta)3/4 variation with straight theta = 8 K. We argue that this novel feature points to anisotropic, due to a layered crystal structure, spin fluctuations near a magnetic ordering. The bulk superconductivity sets in at 0.40 K below which the coherence peak is absent and 1/T1 follows a T3 variation, which suggests unconventional superconductivity with line-node gap.

Journal Article↗
PubMed2001

Evaluation of an Estimation of Physiologic Ability and Surgical Stress (E-PASS) scoring system to predict postoperative risk: a multicenter prospective study.

We previously reported generating a scoring system termed E-PASS that predicted postsurgical risk. This study was undertaken to evaluate the usefulness of this system. A consecutive series of 902 patients who underwent elective gastrointestinal operations in six national hospitals in Japan were prospectively assessed for a comprehensive risk score (CRS) of the E-PASS, which was compared with their postoperative course. The postoperative morbidity rates linearly increased as the CRS increased. The postoperative mortality rate was only 0.13%, when the CRS was below 0.5; however, it increased to 9.7% when the CRS ranged from 0.5 to <1.0, and to 26.9% when the CRS was > or =1.0. The CRS correlated significantly with the severity of postoperative complications (rs = 0.527, P < 0.0001) and the costs of hospital stay (rs = 0.810, P < 0.0001). When the CRS-adjusted mortality rate at the CRS of > or =0.5 was compared among the hospitals, it was related to the hospital volume of operations, being 44.2% at the volume of <100 cases per year, 20.6% at the range of 100-199 cases, and 8.6% at the volume of > or =200 cases. These results suggest that E-PASS may be useful for predicting postsurgical risk, estimating medical expense, and comparing surgical quality.

Adolescent↗
PubMed2001

Different binding sites for the neuropeptide Y Y1 antagonists 1229U91 and J-104870 on human Y1 receptors.

The peptidic Y1 antagonist 1229U91 and the non-peptidic antagonist J-104870 have high binding affinities for the human Y1 receptor. These Y1 antagonists show anorexigenic effects on NPY-induced feeding in rats, although they have completely different structures and molecular sizes. To identify the binding sites of these ligands, we substituted amino acid residues of the human Y1 receptor with alanine and examined the abilities of the mutant receptors to bind the radio-labeled ligands. Alanine substitutions, F98A, D104A, T125A, D200A, D205A, L215A, Q219A, L279A, F282A, F286A, W288A and H298A, in the human Y1 receptor lost their affinity for the peptide agonist PYY, but not for 1229U91 and J-104870, while L303A and F173A lost affinity for 1229U91 and J-104870, respectively. N283A retained its affinity for 1229U91, but not for PYY and J-104870. Y47A and N299A retained their affinity for J-104870, but not for PYY and 1229U91. W163A and D287A showed no affinity for any of the three ligands. Taken together, these data indicate that the binding sites of 1229U91 are widely located in the shallow region of the transmembrane (TM) domain of the receptor, especially TM1, TM6 and TM7. In contrast, J-104870 recognized the pocket formed by TM4, TM5 and TM6, based on the molecular modeling of the Y1 receptor and J-104870 complex. In conclusion, 1229U91 and J-104870 have high affinities for Y1 receptors using basically different binding sites. D287 of the common binding site in the TM6 domain could be crucial for the binding of Y1 antagonists.

Alanine↗
PubMed2001

Chronic cobalt exposure affects antioxidants and ATP production in rat myocardium.

Chronic cobalt exposure is characterized by severe cardiac insufficiency. Since the mechanisms of cobalt toxicity are not yet clear, we analysed the effects of chronic cobalt exposure on antioxidant enzyme activities and myocardial mitochondrial ATP production rate in a rat model. One group of rats was fed a conventional diet and another a cobalt supplemented diet for 24 weeks. The manganese-superoxide dismutase activity was markedly reduced in the cobalt rats (18+/-4.7 U/mg protein) compared to the control rats (100+/-22 U/mg protein; p <0.001). Activity in the respiratory chain enzymes succinate-cytochrome c reductase, NADH-cytochrome c reductase and cytochrome c oxidase was also reduced in the cobalt rats (p<0.01). Glutamate dehydrogenase activity, located in the mitochondrial matrix, was unchanged. The mitochondrial ATP production rate in relation to myocardial mass was lower in the cobalt rats for all substrates tested except palmitoyl-l-carnitine + malate. In conclusion, 24 weeks of chronic cobalt exposure induces a marked decrease in manganese-superoxide dismutase activity, a moderate decrease in mitochondrial ATP production rate and a general reduction in the capacity of the respiratory chain. The impairment in mitochondrial ATP production might be secondary to the decreased manganese-superoxide dismutase activity, causing inactivation of mitochondrial factors susceptible to superoxide radicals.

Adenosine Triphosphate↗
PubMed2001

A typical Y1 receptor regulates feeding behaviors: effects of a potent and selective Y1 antagonist, J-115814.

Neuropeptide Y (NPY) is a potent feeding stimulant. The orexigenic effect of NPY might be caused in part by the action of Y1 receptors. However, the existence of multiple NPY receptors including a possible novel feeding receptor has made it difficult to determine the relative importance of the Y1 receptor in feeding regulation. Herein we certified that the Y1 receptor is a major feeding receptor of NPY by using the potent and selective Y1 antagonist (-)-2-[1-(3-chloro-5-isopropyloxycarbonylaminophenyl)ethylamino]-6-[2-(5-ethyl-4-methyl-1,3-thiazol-2-yl)ethyl]-4-morpholinopyridine (J-115814) and Y1 receptor-deficient (Y1-/-) mice. J-115814 displaced (125)I-peptide YY binding to cell membranes expressing cloned human, rat, and murine Y(1) receptors with K(i) values of 1.4, 1.8, and 1.9 nM, respectively, and inhibited NPY (10 nM)-induced increases in intracellular calcium levels via human Y1 receptors (IC(50) = 6.8 nM). In contrast, J-115814 showed low affinities for human Y2 (K(i) > 10 microM), Y4 (K(i) = 640 nM) and Y5 receptors (K(i) = 6000 nM). Intracerebroventricular (ICV) (10-100 microg) and intravenous (IV) (0.3-30 mg/kg) administration of J-115814 significantly and dose-dependently suppressed feeding induced by ICV NPY (5 microg) in satiated Sprague-Dawley rats. Intraperitoneal (IP) administration of J-115814 (3-30 mg/kg) significantly attenuated spontaneous feeding in db/db and C57BL6 mice. Feeding induced by ICV NPY (5 microg) was unaffected by IP-injected J-115814 (30 mg/kg) in Y1-/- mice and was suppressed in wild-type and Y5-/- mice. These findings clearly suggest that J-115814 inhibits feeding behaviors through the inhibition of the typical Y1 receptor. We conclude that the Y1 receptor plays a key role in regulating food intake.

Animals↗
PubMed2000

Elastase activity enhances the adhesion of neutrophil and cancer cells to vascular endothelial cells.

BACKGROUND: Elastase activity in cancer cells has been reported to promote their metastasis. Hence, we analyzed the influence of elastase activity of cancer cells on their responsive adhesion to vascular endothelial cells. MATERIALS AND METHODS: Human pancreatic (S2-007, S2-013, S2-020, S2-028) and colonic (COLO205) cancer cell lines were used. S2-007, S2-013, and S2-020 possess high elastase activity, whereas S2-028 and COLO205 have low elastase activity. Adhesive reactions of these cancer cells and neutrophils to TNFalpha-activated HUVEC were analyzed. Bound cells onto HUVEC were counted after incubation for 10 min. The effects of suppression of elastase activity by ZD8321, a potent elastase inhibitor, and supplementation of human neutrophil elastase (NE) on the adhesive reactions were also analyzed. In addition, E-selectin expression on HUVEC and concentrations of soluble E-selectin in the medium were measured. RESULTS: Adhesion of cells with high intracellular elastase activity to TNFalpha-activated HUVEC was suppressed by ZD8321. On the other hand, adhesion of cells with low elastase activity was enhanced by exogenous NE. Expression of E-selectin, a key molecule in leukocyte-endothelial cell interaction, on HUVEC was increased by NE. Soluble E-selectin concentration in the medium increased after the adhesive reaction between neutrophils and HUVEC. This increase was thought to be due to the shedding of cell surface E-selectin. Such responses were inhibited by ZD8321. CONCLUSION: Elastase activity has a biological function of stimulating both the E-selectin expression on HUVEC and the resultant adhesive reaction of cancer cells with them. Inhibition of elastase activity is a potent strategy for controlling cancer metastasis.

Cell Adhesion↗
PubMed2000

Clear cell adenocarcinoma with endobronchial polypoid growth.

Clear cell adenocarcinoma of the lung is extremely rare. On radiography, a 45-year-old female with fever was found to have an abnormal shadow in the left lower lung field. Bronchoscopy revealed a polypoid tumor in the left bronchus. On biopsy, the tumor was determined to be adenocarcinoma. Preoperative examination found no tumors outside of the lung. The patient underwent left lower lobectomy with bronchial wedge resection. The tumor had completely obstructed and dilated the left lower bronchus, but had not invaded the tissue outside the bronchial wall. Microscopically, the cytoplasm of the tumor cells contained abundant glycogen, and the tumor had solid and glandular structures. The tumor was diagnosed as clear cell adenocarcinoma of the lung.

Adenocarcinoma, Clear Cell↗
PubMed2000

Tumor necrosis factor alpha acts on cultured human vascular endothelial cells to increase the adhesion of pancreatic cancer cells.

We studied the effect of tumor necrosis factor alpha (TNFalpha), one of the major inflammatory cytokines, on the adhesive reaction of pancreatic cancer cells to human umbilical vein endothelial cells (HUVECs) and on the hepatic metastasis of cancer cells in vivo. After TNFalpha stimulation, the expression of E-selectin, an adhesion molecule to neutrophils on HUVECs, increased. In addition, the adhesion of pancreatic cancer cells to HUVECs increased after TNFalpha stimulation, as was observed with neutrophils. The TNFalpha-induced adhesive response depended on the extent of sialyl Lewis(a) expression on cancer cells. The hepatic metastasis in vivo was often observed when cancer cells expressing a high amount of sialyl Lewis(a) were inoculated intrasplenically after increase in plasma TNFalpha concentration by lipopolysaccharide administration. Because sialyl Lewis(a) on cancer cells is a ligand for E-selectin on HUVECs, as sialyl Lewis(x) on neutrophils, TNFalpha upregulated the adhesive interaction between sialyl Lewis(a) on cancer cells and E-selectin on HUVECs. These results suggest that production of TNFalpha after surgical trauma may stimulate the hematogenic metastasis of cancer cells with a high sialyl Lewis(a) expression.

Animals↗
PubMed1999

Less-invasive surgery for gastric cancer prolongs survival in patients over 80 years of age.

This study was undertaken to determine the most appropriate form of surgery for elderly patients with gastric cancer in relation to postoperative complications and long-term survival. A total of 72 consecutive patients over 80 years of age who underwent partial or total gastrectomy were evaluated using an E-PASS scoring system. This system is comprised of a preoperative risk score (PRS), a surgical stress score (SSS), and a comprehensive risk score (CRS) determined by both the PRS and SSS. Patients with a CRS > or = 0.5 had significantly higher rates of morbidity and mortality at 45.0% and 20.0%, respectively, than those with CRS < or = 0.5, at 17.0% and 2.1%, respectively. A Cox regression analysis of long-term survival, including death from other causes, identified five significant prognostic factors, namely: stage, curability, SSS, CRS, and allogeneic blood transfusion. Among the patients without any apparent residual cancer, a significantly better survival was seen in those who underwent less invasive surgery (SSS < 0.25), those with a CRS < or = 0.5, and those who had not been given a blood transfusion. These results suggest that less invasive surgery not requiring a blood transfusion is advisable for patients over 80 years of age with gastric cancer. Furthermore, gastrectomy with a CRS > or = 0.5 may have a poor therapeutic effect on both early and long-term outcome.

Aged↗
PubMed1999

Estimation of Physiologic Ability and Surgical Stress (E-PASS) as a new prediction scoring system for postoperative morbidity and mortality following elective gastrointestinal surgery.

Overwhelming surgical stress exceeding a patient's reserve capacity causes a disruption of homeostasis, leading to various postoperative complications. This study was undertaken to develop a new scoring system, "E-PASS", standing for the Estimation of Physiologic Ability and Surgical Stress, that predicts the postsurgical risk by quantification of the patient's reserve and surgical stress. E-PASS comprises the preoperative risk score (PRS), the surgical stress score (SSS), and the comprehensive risk score (CRS) that is determined by both scores. These scores were computed by a multiple regression analysis conducted on 292 consecutive patients who underwent elective common gastrointestinal operations at one hospital between 1992 and 1995 (internal group). The usefulness of the scores was evaluated in 989 consecutive patients who underwent the same surgical procedures during the same period at another hospital (external group). The morbidity and mortality rates increased similarly in both groups as the CRS increased. A marked step-up of both rates was observed at a CRS > 1.0, reaching mortality rates of 20% in the internal subjects and 28.5% in the external subjects. These results suggest that the E-PASS scoring system is reproducible, and that it may be useful for surgical decision making. This system requires no special examinations and can be used in every hospital.

Aged↗
PubMed1999

Absence of Mycobacterium paratuberculosis DNA in intestinal tissues from Crohn's disease by nested polymerase chain reaction.

A role of Mycobacterium paratuberculosis in Crohn's disease has been suggested for many years. To determine whether Mycobacterium paratuberculosis has the potential to cause Crohn's disease, we investigated Crohn's disease tissues for the presence of Mycobacterium paratuberculosis, using highly sensitive nested polymerase chain reaction (PCR). DNA was extracted from samples of intestine obtained from 13 patients with Crohn's disease, 14 patients with ulcerative colitis, and 13 control patients without inflammatory bowel disease. Nested PCR was performed using primer pairs complementary to sequences in the insertion element IS900 gene of Mycobacterium paratuberculosis. No Mycobacterium paratuberclulosis-specific PCR product was detected in any of these specimens, although PCR products of the appropriate size were consistently obtained using control DNA template from Mycobacterium paratuberculosis. The results did not suggest that Mycobacterium paratuberculosis is involved in the pathogenesis of Crohn's disease.

Adolescent↗