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Biomedical subjects

Y Ohkawa

Publications and source records attributed to Y Ohkawa.

At least 37 records · Page 2Linked to original sources
PubMed1997

gamma-Pyrones from Gonystylus keithii, as new inhibitors of parathyroid hormone (PTH)-induced Ca release from neonatal mouse calvaria.

New gamma-pyrones, 9'-oxopodopyrone (3) and 8-methyl-9'-oxopodopyrone (4) were isolated from the leaves of Gonystylus keithii, along with known gamma-pyrones, 10'-oxopodopyrone (1) and 8-methyl-10'-oxopodopyrone (2). These gamma-pyrones markedly inhibited the bovine parathyroid hormone (PTH)-induced Ca release from neonatal mouse calvaria in vitro. It is the first time that gamma-pyrones showed inhibitory effects on bone resorption, and these compounds may be seed compounds of new drugs for osteoporosis.

Animals↗
PubMed1997

The course of the mandibular canal in the growing miniature pig.

Miniature pigs are extensively used as laboratory animals in studies concerning craniofacial growth and adaptation. However, in contrast to the vast amount of literature regarding the overall growth pattern of the pig's mandible, little is known about the internal structures of the mandible such as the mandibular canal. In order to investigate the position of the mandibular canal (MC) and the thickness of its buccal and lingual walls, a cross-sectional study was performed on female miniature pigs MINI-LEWE covering the period from newborn to adult. The position of the MC was analyzed at bony segments that were obtained by cutting the drys mandibles interdentally. At each segment a central point of the MC was defined and its relation to the buccal and lingual margin of the mandible was measured. Located at the lower part of the mandibular corpus, the MC runs in the form of an arch within the sagittal plane in anterior direction, getting enlarged into the form of an ampulla in the molar and premolar region. Whereas during the primary dentition the biggest size of the MC was found behind the third deciduous molar, during the secondary dentition the biggest size of the MC was seen in the region of the first and second permanent molar. With regard the buccolingual aspect, the central point of the MC was found mainly in the center of the mandibular corpus. Between the 2nd and 5th month as well as at the beginning of the 18th month the thickest canal wall existed on the buccal side. In the period of the eruption of the succedaneous teeth, however, the lingual wall was thicker than the buccal wall. Results suggest that the definite course of the MC achieves relatively early in the miniature pig with the completion of the primary dentition. There were no major changes of the position of the MC in the postnatal period suggesting that the age factor has only a minor effect on the location of the MC.

Age Factors↗
PubMed1997

[Coronary artery surgery in elderly patients].

We have experienced 351 cases of coronary artery bypass grafting in patients 70 years of age or older (107 cases: 75 years of age or older, 26 cases: octogenarians), among 1,395 cases of all coronary artery bypass grafting surgery. Estimated hospital death rate 4.8% seemed to be satisfactory.

Age Factors↗
PubMed1997

[A case of two stage operation of thoracic and thoracoabdominal aortic aneurysm of a patient in late phase with Behçet's disease].

Patient was a 70-year-old female diagnosed as Behçet's disease 1973. She underwent descending thoracic aortic aneurysm operation 1980. She had graft replacement for a residual thoracoabdominal aortic aneurysm on April 28, 1994. She didn't accept steroid therapy although she had a slight inflammatory reaction on admission. The graft replacement of thoracoabdominal aortic aneurysm was done with an aid of Carmeda closed chest support system bypass and segmental aortic cross clamping. Reattachment of the intercostal and lumbar arteries to the graft was used with button technique or interposition technique. Visceral branches including celiac axis, superior mesenteric and right renal arteries were reconstructed to an opening made in the graft with button technique and reattachment of left renal artery was used with graft interposition during selective perfusion of visceral arteries. She started steroid therapy with 5 mg of predonine to prevent inflammatory reaction postoperatively. The thoracoabdominal aortic aneurysm accompanied with Behçet's disease was relatively rare and this is a long survival case.

Aged↗
PubMed1997

[Simultaneous coronary artery bypass grafting and total arch graft replacement with dextrocardia and situs inversus].

The patient was a 79-year-old male who complained a sudden back pain. He had dextrocardia and situs inversus. An aortogram showed the dilatation of the ascending and aortic arch which reached 5.6 cm in diameter. A coronary angiogram also showed the 75 percent stenosis of segment 3 in the right coronary artery. Coronary artery bypass grafting to the right coronary artery was performed using a saphenous vein graft during cooling stage of the extracorporeal circulation. After that total arch replacement was carried out using a graft with four side branches with an aid of selective cerebral perfusion. He complicated with respiratory failure postoperatively and needed tracheostomy but recovered gradually. A postoperative computed tomogram showed good patency of three side grafts for cerebral perfusion and no abnormality of graft anastomosis.

Aged↗
PubMed1996

A computer-assisted operation for congenital aural malformations.

Surgical procedures to correct malformations of the external auditory canal are associated with the risk of facial nerve injury. We operated on a 6-year-old boy with a stenotic external auditory canal using a Viewing Wand (ISG Technologies Inc., Mississauga, Ontario, Canada) for improved visualization. We present our experience using this imaging system for aural surgery.

Child↗
PubMed1996

Flavones with antibacterial activity against cariogenic bacteria.

Methanolic extracts obtained from 13 plants were studied for their antibacterial activity against cariogenic bacteria. Among them, the extract from Artocarpus heterophyllus showed the most intensive activity. Serial chromatographic purifications offered two active compounds which were identified as 6-(3-methyl-1-butenyl)-5,2',4'-trihydroxy-3-isoprenyl-7-methoxy flavone and 5,7,2',4'-tetrahydroxy-6-isoprenylflavone. Both isolates completely inhibited the growth of primary cariogenic bacteria at 3.13-12.5 micrograms/ml. They also exhibited the growth inhibitory effects on plaque-forming streptococci. These phytochemical isoprenylflavones would be potent compounds for the prevention of dental caries.

Anti-Bacterial Agents↗
PubMed1996

Developmental stage-specific and nitrate-independent regulation of nitrate reductase gene expression in rapeseed.

cDNA clones for two isogenes of nitrate reductase (NR) have been isolated from rapeseed (Brassica napus L.) androgenetic haploid embryos induced by microspore culture. NR mRNA accumulation can be detected by northern hybridization at 14 d after culture initiation when embryos develop to the heart/torpedo-shaped stage. Whole-mount in situ hybridization experiments demonstrate that the mRNA accumulation is developmental stage specific. In addition, even when cultured in media containing no nitrate, embryos accumulated NR mRNA to almost the same level as the control. This indicates the unique regulation of NR in embryogenesis in which NR mRNA transcription is activated in a developmental stage-specific manner that is independent of nitrate induction. In zygotic embryogenesis, a stage-specific accumulation of NR mRNA was also observed. By contrast, the obvious effect of nitrate on NR expression that has been reported in many plant species was also confirmed in rapeseed leaf. Quantitative combined reverse transcription-polymerase chain reaction analysis suggests that the flexible and variable regulation of NR expression, which is organ specific, nitrogen metabolite specific, and developmental stage specific, is caused principally by regulation of one major structural gene.

Base Sequence↗
PubMed1996

Splenectomy-reduced hepatic injury induced by ischemia/reperfusion in the rat.

In the present study, we investigated the role of the spleen in experimental hepatic ischemia/reperfusion in the rat. After a 90-min period of ischemia in the left and middle hepatic lobes, the ischemia was released and the liver was reperfused for up to 24 h. Plasma alanine aminotransferase reached a peak 3 h after the onset of reperfusion, and gradually decreased thereafter. A histological examination revealed evidence of hepatocellular necrosis and degeneration, especially 24 h after the onset of reperfusion. In addition, there was a noticeable accumulation of polymorphonuclear cells in the liver following ischemia/reperfusion. A splenectomy performed just prior to ischemia/reperfusion reduced both biochemical and histological hepatocellular injury. The number of polymorphonuclear cells in the liver following ischemia/reperfusion was significantly reduced in rats subjected to splenectomy, suggesting that the increase in polymorphonuclear cells may contribute to liver injury. The number of mononuclear cells also increased in the marginal zones of the spleen following ischemia/reperfusion, and appeared to be derived from the splenic monocyte/macrophage population, based on immunohistochemical studies. The spleen plays an important role in the pathogenesis of hepatic ischemia/reperfusion injury and the splenic monocyte/ macrophage population contributes to liver damage.

Alanine Transaminase↗
PubMed1996

[Simultaneous aortic root and total arch graft replacement in a patient with aortitis syndrome].

The patient was a 45-year-old female diagnosed with aortitis syndrome and aortic regurgitation (AR). She had been taking steroid therapy since 1975. She had recently developed congestive heart failure due to AR while both the ascending aorta and aortic arch were enlarged. She had no inflammatory reaction on admission. An aortogram showed heavy dilation of both the ascending aorta and aortic arch and maximum diameters was 11 cm in the ascending aorta and 4.5 cm in the descending aorta. There was an obstruction of the left subclavian artery. Moderate AR was seen on an echocardiogram. She had a simultaneous graft replacement of aortic root and total arch. The aortic root was replaced with composite graft and coronary arteries were implanted using Carrel's patch technique, and the aortic arch was also replaced with a graft with two side branches. The postoperative course was uneventful without complication of cerebral infarction or paraplegia. The postoperative aortogram showed stenosis of the left carotid artery, but no abnormality of the coronary orifices and graft anastomosis. She returned home with disappearance of symptoms of congestive heart failure.

Aorta↗
PubMed1995

[The graft replacement of the patient with aortic arch aneurysm and thrombosed aortic dissection].

The patient was male and aged 68 years and complained of dyspnea and chest pain. He was pointed out aortic arch dilatation on chest X-ray and CT demonstrated aortic arch aneurysm accompanied with acute type IIIb aortic dissection. One month later after anti-hypertensive therapy, the false lumen of aortic dissection was closed with thrombus. While we performed the graft replacement to the aortic arch aneurysm, the thrombosed false lumen was recanalized, so it needed the closure of the false lumen reinforced with teflon felt. Postoperative angiography showed no abnormality of anastomosis and complete occlusion of the false lumen.

Aged↗
PubMed1995

[Primary hyperparathyroidism in young patients].

Five young patients with primary hyperparathyroidism were treated in our hospital. Male to female ratio was 3 to 2 and the mean age was 12.2 years old. Hypercalcemia due to a single adenoma of the parathyroid gland was found in all cases. They showed various clinical symptoms, such as abdominal pain, nausea, convulsions and disturbance of walking. Parathyroid tumors usually could be easily identified with ultrasonography or CT scan or thyroid subtraction scintigraphy. But in two cases parathyroid tumor was not found during operation. Angiography and/or venous sampling were performed and they showed the right localization.

Adolescent↗
PubMed1994

Liver resection in children, using a water-jet.

The water-jet method has been used during hepatic resection in children. The instrument cuts the hepatic tissue by means of a high-pressure fine water-jet, while the exposed intrahepatic vessels are spared injury. Physiological saline was used for the jet water, and pressure of 12 to 15 kilograms of force per square centimeter (kgf/cm2) through a 0.15-mm-diameter nozzle was found to be optimal for cutting the liver parenchyma. The authors evaluated the usefulness of the water-jet dissector (n = 8) during bisegmentectomy or trisegmentectomy in comparison to the Cavitron Ultrasonic Surgical Aspirator (CUSA) (n = 5). The mean operation time was 4.08 +/- 0.87 hours for the water-jet group and 5.08 +/- 1.33 hours for the CUSA group. The mean blood loss was 602 +/- 659 mL for the water-jet group and 1,036 +/- 521 mL for the CUSA group. Although there were no significant differences with respect to operation time, blood loss, or postoperative complications, the liver parenchyma was dissected more easily using the water-jet. The authors believe that the mechanical simplicity and safety of the water-jet method will lead to its more widespread use in liver resection in children.

Blood Loss, Surgical↗
PubMed1994

Congenital biliary dilatation with pancreatico-biliary maljunction: a comparative study between children and adults.

A comparative study of congenital biliary dilatation with pancreatico-biliary maljunction in 15 children and 16 adults was undertaken. Cystic and fusiform dilatation of the common bile duct was seen in 9 and 6 cases respectively in the child group, with 8 and 8 cases respectively in the adult group. Cholangiographically, neither the length of the common channel nor the type of pancreatico-ductal union varied significantly between groups. Furthermore the incidence of higher amylase levels of bile showed no apparent variance from group to group. This was also true when looking histologically at the number and distribution of periductal glands surrounding the intra-hepatic bile duct. Therefore, we concluded that there was no essential etiological difference between the two groups.

Adult↗
PubMed1994

Flavanones with potent antibacterial activity against methicillin-resistant Staphylococcus aureus.

With the therapeutic concept of using the defensive ability of plants against microbial infections, phytoalexin, an antimicrobial phytochemical was studied for its ability to inhibit the growth of methicillin-resistant Staphylococcus aureus (MRSA). Extracts from Sophora exigua (Leguminosae) were fractionated by serial chromatography and the anti-MRSA activity of each fraction was determined by the agar-plate method. Among the active isolates, 5,7,2',6'-tetrahydroxy-6-isoprenyl-8-lavandulyl-4'-methox yflavanone (exiguaflavanone D) completely inhibited the growth of all the MRSA strains examined at the concentration of 1.56-6.25 micrograms mL-1, and 5, 2',6'-trihydroxy-8-lavandulyl-7-methoxy-flavanone (exiguaflavanone B) inhibited at a concentration of 50 micrograms mL-1. This former compound is expected to be a phytotherapeutic agent for MRSA infections as an alternative to conventional antibiotics with unwanted side-effects or the appearance of antibiotic-resistant bacteria.

Anti-Bacterial Agents↗
PubMed1994

Occlusion of the posterior humeral circumflex artery: detection with MR angiography in healthy volunteers and in a patient with quadrilateral space syndrome.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of MR angiography in detecting occlusion of the posterior humeral circumflex artery and to determine if the finding is specific for the diagnosis of quadrilateral space syndrome. SUBJECTS AND METHODS: Two-dimensional fast low-angle shot MR angiography was used to image both shoulders of one symptomatic patient and six asymptomatic volunteers (10 posterior humeral circumflex arteries). RESULTS: With the arm in a neutral position, the posterior humeral circumflex arteries appeared normal on MR angiograms of all subjects. However, when the arm was in abduction, occlusion of the posterior humeral circumflex artery was seen both in the symptomatic patient and in 80% of the asymptomatic volunteers. CONCLUSION: Our data show that occlusion of the posterior humeral circumflex artery is common in asymptomatic volunteers. Thus, MR angiography has no value in the diagnosis of quadrilateral space syndrome.

Adult↗
PubMed1993

Philadelphia-chromosome-positive, monosomy 7 biphenotypic acute mixed lineage leukemia in adults: a pluripotent stem cell disorder.

Two adult patients with acute mixed lineage leukemia (AMLL) having combined Philadelphia chromosome (Ph1) positivity and monosomy 7 are presented. The phenotypes of leukemic blasts from both cases were almost same (early B-lymphoid lineage and myeloid lineage); CD10+, CD13+, CD19+. HLA-DR+, and dual-color analysis showed simultaneous expression of CD10 (CD19) and CD13 antigens in individual blasts (biphenotypic) in both cases. On molecular analysis, the leukemic blasts showed rearrangement in the first intron of the BCR gene with breakpoint just outside of 3' end of m-BCR-2 (bcr 3) in case 1, and in the M-BCR in case 2. Immunoglobulin heavy chain gene (IgH) rearrangement was noted in both cases, but rearrangement of the T-cell receptor beta-chain gene (TCR beta) was detected only in case 1. Clinically, both cases achieved complete remission by the combination chemotherapy consisting of L-asparaginase, doxorubicin, vincristine, and prednisolone (L-AdVP). In remission, all these molecular abnormalities disappeared in both patients. These results suggest that the Ph1-positive and monosomy 7 AMLL in adults is de novo acute leukemia with both early B-lymphoid and myeloid phenotypes and may arise from malignant transformation of pluripotent stem cell, and expresses a heterogenous rearrangement pattern of the BCR gene.

Acute Disease↗