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Biomedical subjects

Y Yamazaki

Publications and source records attributed to Y Yamazaki.

At least 307 records · Page 17Linked to original sources
PubMed1997

[Pulmonary disease caused by Mycobacterium avium presenting as a solitary cavity with a thickened wall].

A 46-year-old man was admitted for evaluation of a solitary pulmonary cavity in the apey of the left lung. Because two transbronchial biopsies followed by brushing and washing and sputum cytology did not yield any diagnostic findings, the patient was treated with INH, RFP and SM under a tentative diagnosis of pulmonary tuberculosis. The shadow decreased over two months with combination therapy, but increased again after the dose of SM was decreased. We performed a left upper lobectomy to diagnose either multi-drug-resistant pulmonary tuberculosis or lung cancer. Pathological examination of the resected lung revealed epitheloid cell granulomas with areas of caseous necrosis. Smooth chromophoric colonies were isolated on an Ogawa egg medium, and were identified as M. avium by PCR and DDH. A diagnosis of pulmonary M. avium was made. A chest X-ray film taken two years later was normal. Pulmonary M. avium disease developed in this patient, who had no predisposing lung pathologies.

Diagnosis, Differential↗
PubMed1996

Molecular identification and characterization of cytosolic isoforms of glutamine synthetase in maize roots.

In maize, a small multigene family encodes the cytosolic isoforms of glutamine synthetase (GS), and five cDNAs, designated pGS1a, pGS1b, pGS1c, pGS1d, and pGS1e, have been cloned (Sakakibara, H., Kawabata, S., Takahashi, H., Hase, T., and Sugiyama, T. (1992) Plant Cell Physiol. 33, 49-58; Li, M., Villemur, R., Hussey, P. J., Silflow, C. D., Gantt, J. S., and Snustad, D. P. (1993) Plant Mol. Biol. 23, 401-407). This report describes the identification and enzymatic characterization of the cytosolic isoforms of GS in maize roots, namely GS1 and GSr. The purified isoforms, as well as recombinant enzymes that had been overexpressed in Escherichia coli, were analyzed by capillary liquid chromatography/electrospray ionization-mass spectrometry, and GS1 and GSr were identified as the products of the GS1a/GS1b and GS1c/GS1d genes, respectively. Upon the addition of ammonia to the culture medium, significant amounts of GSr accumulated and a preferential increase in GS synthetase activity, as compared to GS transferase activity, was found in the root extract. Assays with the purified recombinant enzymes confirmed that the specific biosynthetic and synthetase activities of GSr were 1.6-fold higher than those of GS1. Marked differences in stability were also found between the two isoforms: GSr was more sensitive to heat than GS1 and octameric aggregates of the subunits of GSr were easily dissociated to monomers than those of GS1 at low concentrations of Mn2+ and Mg2+ ions. These characteristics of the ammonia-induced isoform of GS seem to be physiologically important for the primary assimilation of external ammonia by roots.

Ammonia↗
PubMed1996

Three-dimensional labeling program for elucidation of the geometric properties of biological particles in three-dimensional space.

For all biological particles such as cells or cellular organelles, there are three-dimensional coordinates representing the centroid or center of gravity. These coordinates and other numerical parameters such as volume, fluorescence intensity, surface area, and shape are referred to in this paper as geometric properties, which may provide critical information for the clarification of in situ mechanisms of molecular and cellular functions in living organisms. We have established a method for the elucidation of these properties, designated the three-dimensional labeling program (3DLP). Algorithms of 3DLP are so simple that this method can be carried out through the use of software combinations in image analysis on a personal computer. To evaluate 3DLP, it was applied to a 32-cell-stage sea urchin embryo, double stained with FITC for cellular protein of blastomeres and propidium iodide for nuclear DNA. A stack of optical serial section images was obtained by confocal laser scanning microscopy. The method was found effective for determining geometric properties and should prove applicable to the study of many different kinds of biological particles in three-dimensional space.

Animals↗
PubMed1996

Sulphatide binds to human and animal influenza A viruses, and inhibits the viral infection.

We found, by using a virus overlay assay, that influenza A virus isolates bind to sulphatide (HSO3-Gal beta 1-->1'Cer), which has no sialic acid residue, and that the infection of Madin-Darby canine kidney cells with the human influenza virus A/Memphis/1/71 (H3N2) is inhibited by sulphatide. A/Memphis/1/71 (H3N2) causes obvious haemagglutination and low-pH haemolysis of asialoerythrocytes reconstituted with sulphatide. All influenza A virus isolates from the species of animals so far tested bound to sulphatide. The sulphatide-binding specificity of the isolates was different from the viral sialyl-linkage specificity. Influenza A virus isolates also bound to galactosyl ceramide (GalCer; Gal beta 1-->1'Cer), as well as sulphatide, in the virus overlay assays. In contrast, the influenza virus did not bind to N-deacyl, a derivative of sulphatide, glucosyl ceramide or the other neutral glycolipids tested. These results indicate that the linkage of galactose, or sulphated galactose, to ceramide is important for viral binding.

Animals↗
PubMed1996

Mutations in the p53 gene and human papillomavirus infection as significant prognostic factors in squamous cell carcinomas of the oral cavity.

The p53 gene has been indicated to be a tumour suppressor gene that is found in mutated form in common human cancers. Human papillomavirus (HPV) has oncogenic activity in cervical and oral squamous cell carcinomas (SCCs). The E6 protein of HPV is known to bind with p53 protein and inactive the tumor suppressor activity by promoting p53 degradation. Because of this background, we examined 38 primary, resected specimens of oral SCCs for detection of p53 mutations and HPV DNAs. Exons 5 through 8 of the p53 Mutations were observed in nine cases (24%). HPV-DNA detection and typing were performed using PCR with ¿high risk group' HPV-specified primers. HPV DNA sequences were detected in eight cases (21%). The AvaII digestion pattern of PCR-amplified HPV DNA showed that HPV-16 was present in all eight cases. Seven cases were p53 mutation-positive/HPV-negative, six cases were p53 mutation-negative/HPV-positive, and two intraosseus SCC cases were p53 mutation-positive/ HPV-positive. Thus, 15/38 (40%) cases had inactivation of the p53 protein. Interestingly, p53 mutation-negative/ HPV-negative cases had a poorer prognosis than p53 mutation positive or HPV-positive cases (P < 0.01). We conclude that (1) mutation in the p53 gene and/or HPV infection are frequent (40%) in oral SCC; (2) inactivation of p53 function by mutation and HPV infection are important genetic events in the development of 40% integral of oral SCCs; (3) p53 mutation and HPV infection are not mutually exclusive events and (4) other oncogenes or tumor suppressor genes may be crucial in the development of oral SCC if the prognosis is poor.

Aged↗
PubMed1996

Hydrogen bonds of water and C==O groups coordinate long-range structural changes in the L photointermediate of bacteriorhodopsin.

Fourier transform infrared spectra of light-adapted bacteriorhodopsin exhibit a band at 1618 cm(-1) that shifts to 1625 cm(-1) upon formation of the L intermediate. It is assigned to the peptide C==O of Val49 from the fact that it shifts in [1-(13)C]valine-labeled bacteriorhodopsin and appears perturbed in the Val49-->Met mutant. The intensity of the BR-->L difference band is reduced in the Thr46-->Val mutant but restored by the additional mutation of Asp96-->Asn. These intensity changes are closely correlated with the H-bonding change of water olecules, suggesting that the peptide C==O of Val49 is hydrated. This could arise in the Thr46-->Val mutant because of perturbation of the C==O of Val46, which points toward Val49. The Val49-->Ala mutation influences a peptide N-H, presumably of Val49, and the carboxylic C==O of Asp96, as well as water molecules proximal to Asp85. Conversely, the water molecule assumed to be in the cavity that arises from the missing two methyl groups in V49A could be affected in the mutant of Asp96-->Asn. We propose that the perturbation exerted on Asp85 by the Schiff base in the L intermediate is transmitted to Asp96 through H-bonding of water molecules in the Asp85-Val49 region, the C==O of Val49, H-bonding between Val49 and Thr46, and H-bonding between Thr46 and Asp96.

Amino Acid Sequence↗
PubMed1996

Ectopic induction of cartilage and bone by bovine bone morphogenetic protein using a biodegradable polymeric reservoir.

Two kinds of bone morphogenetic protein (BMP) containing polymeric reservoirs made from poly(lactide-co-glycolide) (PLG) and a mixture of PLG/poly(ethylene glycol) (PEG) (PLG/PEG) were implanted into mice femoral muscles. In the PLG/PEG reservoir with BMP, bone formation was induced within 3 weeks. On the other hand, in the PLG reservoir with BMP scarcely any bone formation could be observed. The results suggest that the carrier system is most important for the development of BMP-induced bone formation and the PLG/PEG reservoir system is available for BMP delivery.

Animals↗
PubMed1996

Bone morphogenetic protein encapsulated with a biodegradable and biocompatible polymer.

To develop a controlled release system for bone morphogenetic protein (BMP), poly(DL-lactide-co-glycolide) (PLGA) capsules containing BMP were prepared by an interfacial precipitation method using a water-in-oil-in-water emulsion. The surface morphology, particle size distribution, and hydrolytic degradation rate of the PLGA capsules were examined. The encapsulation yield and release rate of BMP in vitro were measured using fluorescein isothiocyanate-labeled BMP. The amount of BMP released from PLGA capsules increased between days 3 and 5. In addition, the effectiveness of BMP encapsulated in PLGA to induce bone formation in vivo was also examined by subcutaneous implantation in rats. Complete digestion of the capsules and new bone formation including bone marrow were identified by histologic examination of harvested tissues at 3 weeks after implantation. These results demonstrated that encapsulation of BMP with PLGA could be a promising method to induce bone in clinics.

Animals↗
PubMed1996

Spontaneous hemopneumothorax.

BACKGROUND: Spontaneous hemopneumothorax is a rare disorder, occurring in 1% to 12% of patients with spontaneous pneumothorax. We studied our previously treated patients to determine the nature of optimal operative management. METHODS: This was a retrospective case study. From 1987 to 1994, of 428 cases of spontaneous pneumothorax that occurred in 234 patients treated at our institution, hemopneumothorax developed in 10 patients (2.3%). The clinical features of these patients were studied. RESULTS: The amount of bleeding ranged from 600 to 1,600 mL, and 3 patients exhibited symptoms of shock, such as sweating, nausea, and syncope. Six patients underwent operation within 7 days from the onset, and this involved resection of the bullae or pneumorrhaphy, or both. The source of bleeding was identified in 5 patients. Pathologic examination showed marked fibrosis with alcian blue-positive deposits of aberrant vessels. All 6 patients continue to be well postoperatively without recurrence or complications. Four patients did not undergo early thoracotomy. However, decortication was required in 3 of these patients because of a reactive fluid collection in the pleural space, which led to impaired lung expansion. CONCLUSIONS: Early surgical repair should be considered once diagnosis of a spontaneous hemopneumothorax is confirmed, because this provides better long-term results. Video-assisted thoracoscopic surgery as well as minithoracotomy should be considered as surgical options because of the improved quality of life they confer.

Adolescent↗
PubMed1996

The dual expression of minor and major bcr/abl chimeric mRNA in blast crisis of chronic myelogenous leukemia.

The hypothesis that minor bcr/abl fusion mRNA is produced in blast crisis of chronic myelogenous leukemia (CML) is examined. The RNA transcripts encoding the minor and major bcr/abl fused protein were detected by polymerase chain reaction (PCR) using RNA from peripheral blood or bone marrow cells of eight patients with blast crisis or accelerated phase of CML. The mRNA encoding for major bcr/abl was detected in all eight cases. In four patients, however, transcripts encoding for minor bcr/abl mRNA were detected, as well as major bcr/abl mRNA. The presence of minor bcr/abl mRNA was verified with the hybridization with a junction-specific probe and DNA sequencing analysis of PCR products. The appearance of minor bcr/abl fusion mRNA was associated with the lymphoblastic immunophenotype of the blast cells. In two of these four patients, samples of initial diagnosis of chronic phase of CML were available, which did not show minor bcr/abl transcript. We conclude that the appearance of minor bcr/abl mRNA transcript is associated with the terminal evolution of CML in lymphoblastic crisis.

Adolescent↗
PubMed1996

Elevated levels of nitric oxide in synovial fluid from patients with temporomandibular disorders.

OBJECTIVE: The objective of this study was to measure nitric oxide activity in synovial fluid samples taken from patients with temporomandibular disorders. STUDY DESIGN: We investigated six volunteers without symptoms and 56 patients with temporomandibular disorders. Nitric oxide activity was measured in temporomandibular joint synovial fluid with a highly sensitive and specific chemiluminescence detection method. RESULTS: A detectable nitrite concentration was found in only 1 of 10 joints in the control group. Measurable levels (> 0.001 mol/l) of nitrites in the synovial fluid were found in 8 (72.7%) of 11 joints with disk derangement with clicking, 24 (85.7%) of 28 joints with disk derangement with locking, and all 26 (100%) joints with osteoarthritis. The mean nitrite concentrations in the temporomandibular joint synovial fluid in the disk derangement with clicking, disk derangement with locking, and osteoarthritis groups were significantly higher than that in the control group (p < 0.05, p < 0.001, p < 0.001, respectively). CONCLUSIONS: These data clearly show increased nitric oxide production in certain temporomandibular disorders and suggest that nitric oxide may play a role in the pathogenesis of synovitis and degenerative changes of cartilaginous tissue and bone of the temporomandibular joint.

Adolescent↗
PubMed1996

Detection of ultraviolet photoproducts in mouse skin exposed to natural sunlight.

In the present study, we for the first time investigated the formation of ultraviolet (UV) photoproducts, cyclobutane pyrimidine dimers (CPDs), pyrimidine-pyrimidone (6-4) photoproducts (64PPs) and Dewar isomers, in vivo in shaved and depilated C3H/HeN mouse skin exposed to natural sunlight (NSL) at noon for 5 min to 1 h in mid-summer, using a highly sensitive immunohistochemical method. This method permits the quantitative analysis of UV-photoproducts in formalin-fixed, paraffinembedded sections with specific antibodies against CPDs, 64PPs and Dewar isomers. We demonstrated that the induction of CPDs in vivo in mouse skin by NSL was exposure time-dependent, but the accumulation of 64PPs or Dewar isomers was comparatively low in the skin sections from mice exposed to NSL in vivo. The results indicate that CPDs are the main photoproducts in vivo induced by sunlight and that their formation and repair may be important in connection with carcinogenesis in sun-exposed areas of human skin.

Animals↗
PubMed1996

Profile of Helicobacter pylori cytotoxin derived from two areas of Japan with different prevalence of atrophic gastritis.

BACKGROUND AND AIM: To clarify the roles of Helicobacter pylori cytotoxin in gastric atrophy, the cytotoxin positive rate and cytotoxin activity in Fukui and Okinawa, where the prevalence of atrophic gastritis and gastric cancer risk are quite different, were studied. MATERIALS: Seventy three strains from Fukui and 51 from Okinawa were examined. METHODS: The validation of atrophy was done by endoscopy, being confirmed with histology. The supernatant of liquid H pylori culture media was concentrated 20-fold, serially diluted, using doubling dilutions, and scored from 1 to 8. The semi-quantitated cytotoxin activity was expressed as the maximum dilution score yielding > 50% A431 cell vacuolation, being standardised with bacterial density. RESULTS: The cytotoxin activity of the strains from Fukui was highly diverse compared with that from Okinawa, although the cytotoxin positive rate was not different. In Fukui strains, the grade of atrophy and the cytotoxin activity were correlated (p < 0.05). In addition, the cytotoxin activity of the strains from all patients in Okinawa, most of whom showed closed-type/mild atrophy, was significantly lower than that of the strains from the patients with open-type/severe atrophy in Fukui (6.46 (5.53) v 9.76 (8.80), p < 0.05), (mean (SEM)). CONCLUSION: The difference in profile of the cytotoxin activity in the two areas was related to the difference in the prevalence of atrophic gastritis.

Adult↗
PubMed1996

Application of the minimum jerk model to formation of the trajectory of the centre of mass during multijoint limb movements.

Smoothness of movement is an inherent characteristic of the motor repertoire of primates. According to the minimum hand jerk model, a major feature of motor coordination in two-joint upper limb movements by humans in the horizontal plane is the production of the smoothest possible movement of the end effector, the hand ('hand version'). In the present study, this model was extended to the formation of the trajectory of the centre of mass (CMt) of the whole arm system ('CMt version'), and its importance for the shaping of multijoint movements was tested against the classical 'hand version'. During point-to-point movements between many pairs of targets in the work space, the movements of the CMt showed lower changes of torque than in movements of the hand on a straight path. Furthermore, the CMt version of the minimum jerk model reproduced the curved hand trajectory that can be observed in actual human performance. Under the assumption that the smoothness criterion is induced by a high-level motor coordination, our results suggest that CMt-based planning can be an alternative strategy for joint coordination. It offers the advantage of the simplified scaling of joint torques which are suitable for execution of planned movements.

Computer Simulation↗
PubMed1996

[Behavioral studies of KSG-504, a new CCK-A receptor antagonist].

The effects of KSG-504 after intravenous administration on behavior and other central functions were studied. KSG-504 did not affect the general behavior of dogs up to the dose of 30 mg/kg, but the drug (100 mg/kg, i.v.) caused vomiting in 3 out of the 5 dogs. Moreover, KSG-504 (1-30 mg/kg, i.v.) had no effects on spontaneous motility, thiopental-induced sleep, acetic acid-induced writhing in mice and satiety in rats. A high dose of CCK-8 (100 micrograms/kg or more) suppressed spontaneous motility, writhing and satiety, and prolonged sleep when administered subcutaneously. The behavioral changes induced by CCK-8 were antagonized by KSG-504 in a dose-dependent manner (1-30 mg/kg, i.v.). When KSG-504 was administered intravenously to rabbits at the dose of 10 mg/kg or 0.5 mg/kg/min for 120 min, we could not detect the drug in the cerebrospinal fluid, indicating that KSG-504 does not cross the blood-brain barrier after peripheral administration of the drug. Thus, the inhibitory effect of KSG-504 on CCK-8-induced behavioral changes may be the result of antagonism at peripheral CCK-A receptors.

Animals↗
PubMed1996

[Effects of KSG-504, a new CCK-A receptor antagonist, on gallbladder and gastrointestinal functions].

We investigated the interaction of KSG-504 with CCK-8- or pentagastrin-induced gallbladder and gastrointestinal responses in vitro and in vivo. KSG-504 (10(-7)-10(-4) M) inhibited CCK-8-induced contractions of both isolated guinea pig gallbladder and rabbit terminal cavity of the bile duct in a concentration-dependent manner. Furthermore, intravenous administration of KSG-504 also dose-dependently inhibited CCK-8-induced gallbladder contraction in anesthetized guinea pigs with an IC50 value of 0.23 mg/kg. In conscious mice, KSG-504 inhibited both CCK-8- and egg yolk-stimulated gallbladder emptying in a dose-dependent manner (IC50: 13.3 and 9.6 mg/kg, respectively). The CCK-8-induced delay of gastric emptying in conscious rats was also antagonized by KSG-504 with an IC50 value of 3.78 mg/kg, i.v., whereas pentagastrin-stimulated gastric acid secretion in anesthetized rats was not affected by KSG-504 at all. KSG-504 (1 mg/kg, i.v.) also inhibited CCK-8-induced duodenal and jejunal contractions in anesthetized rabbits. These results indicate that KSG-504 exerts an antagonistic effect on CCK-A receptors in the gastrointestinal tract, but not on gastrin receptors in the stomach.

Animals↗