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Biomedical subjects

H Obata

Publications and source records attributed to H Obata.

At least 37 records · Page 2Linked to original sources
PubMed2000

Accuracy of carboxyhemoglobin dilution method for the measurement of circulating blood volume.

PURPOSE: The management of circulating blood volume (BVc) is crucial in intensive care unit (ICU) patients. The purpose of this study was to verify the accuracy and precision of the carbon monoxide-labeled hemoglobin (CO-Hb) dilution method (CO method) by comparing it with the 51Cr-labeled erythrocyte dilution method (51Cr method) for the measurement of BVc. METHODS: A prospective study was performed in 18 patients who underwent coronary artery bypass grafting (CABG) under mild hypothermic cardiopulmonary bypass (CPB). The BVc was measured by both the CO method and the 51Cr method at 24 hr after ICU admission in order to verify the accuracy and precision of the CO method. Paired data were assessed in absolute terms, and percentage errors were calculated by the degree of agreement. RESULTS: Small mean differences and standard deviations between the CO method and the 51Cr method (-70.2 +/-184.8 mL) and small percentage errors (-0.49+/-1.29%) indicated the accuracy and precision of the CO method, and a close correlation was observed (r = 0.97). CONCLUSION: The CO method can measure BVc with a similar degree of accuracy as the 51Cr method. It is simple, repeatable and safe without the risk of exposure to radioactivity in the ICU.

Blood Volume↗
PubMed2000

Reduction of cerebral hyperemia with anti-hypertensive medication after electroconvulsive therapy.

PURPOSE: Several different anti-hypertensive regimens have been introduced for the prevention of systemic hyperdynamic responses after electrically induced seizures. In the present study, the effects of anti-hypertensive medications on cerebral circulation were studied. METHODS: Systemic blood pressure was controlled by several anti-hypertensive medications, nicardipine, prostaglandin EI, alprenolol and nitroglycerin, in 30 patients (150 electroconvulsive therapy trials). Changes in cerebral blood flow velocity were measured by transcranial Doppler sonography of the right middle cerebral artery from the start of anesthesia to 10 min after the electrical shock. RESULTS: Administration of a Ca2+ antagonist, nicardipine, or prostaglandin EI did not alter the augmented cerebral blood flow velocity after the seizure. However, a beta-adrenergic blocking agent, alprenolol (P<0.05) or nitroglycerin (P<0.01) partially inhibited the increase in cerebral blood flow velocity. Maximal blood flow velocity was 133% larger than the pre-anesthesia value in the control group, 109% in the nicardipine group, 113% in the prostaglandin EI group, 72% in the alprenolol group, and 45% in the nitroglycerin group, respectively. The increase in cerebral blood flow velocity after electrically induced seizure was independent of systemic blood pressure. Internal jugular venous saturation (SjO2) was increased, and difference in arterial and venous concentrations of lactate was not altered in all groups. CONCLUSIONS: Cerebral hemodynamics is altered by ECT, even when systemic hemodynamics are stabilized by antihypertensive medication. Although the effects of antihypertensive medicine on cerebral hemodynamics are variable, systemic blood pressure control by these agents does not induce cerebral ischemia after ECT.

Adult↗
PubMed2000

Effect of anti-inflammatory agents on corneal wound-healing process after surface excimer laser keratectomy.

PURPOSE: To investigate the effect of anti-inflammatory agents on conjunctival inflammation and corneal haze formation after excimer laser keratectomy. SETTING: Department of Ophthalmology, University of Tokyo Faculty of Medicine, Tokyo, Japan. METHODS: After excimer laser keratectomy was performed in 21 rabbits (42 eyes), saline, betamethasone 0.1%, or diclofenac 0.1% was topically applied 6 times a day for 4 weeks and then 3 times a day for 8 weeks. The degree of conjunctival inflammation was determined 1, 2, 3, and 7 days after the keratectomy. The degree of corneal haze was quantitatively measured using a digital analyzer before and once a week after the keratectomy. The expression of type IV collagen in the corneas at baseline and 4 and 12 weeks after the keratectomy was examined immunohistochemically. RESULTS: Compared with saline, betamethasone and diclofenac significantly decreased early-phase conjunctival inflammation. Betamethasone significantly inhibited corneal haze formation compared with saline at 3 to 5 and 8 to 12 weeks. Diclofenac did not inhibit corneal haze formation significantly. Although betamethasone tended to be more effective in inhibiting corneal haze formation and deposition of type IV collagen than diclofenac, there was no statistical difference between the 2 anti-inflammatory agents. CONCLUSION: Topically applied betamethasone effectively suppressed corneal haze formation after excimer laser keratectomy. Diclofenac was not statistically effective in inhibiting corneal haze formation.

Animals↗
PubMed2000

Analysis of liquid accumulated in the distended capsular bag in early postoperative capsular block syndrome.

PURPOSE: To analyze the transparent liquid between the posterior lens capsule and the posterior chamber intraocular lens (PC IOL) in early postoperative capsular block syndrome and discuss the mechanism of posterior capsule distention. SETTING: Department of Ophthalmology, Tokyo University School of Medicine, and Tokyo Research Institute, Seikagaku Corporation, Tokyo, Japan. METHODS: This study evaluated 3 cases of capsular block syndrome presenting with transparent liquid in the distended capsular bag 1 day after cataract surgery. The transparent liquid material between the posterior capsule and PC IOL was aspirated and analyzed using high-performance liquid chromatography (HPLC). Also, sodium hyaluronate was diluted using a dialyzer to determine whether the aqueous humor was drawn into the capsular bag by an osmotic gradient across the capsule. RESULTS: The elution time of the samples was almost the same as that of sodium hyaluronate 1.0% (Healon) The concentration of the samples ranged from 3.29 to 9. 01 mg/mL by HPLC analysis. The sodium hyaluronate absorbed the physiological salt solutions through the dialyzer and expanded to 1. 9 times its original volume. CONCLUSIONS: These results indicate that the main ingredient of the transparent liquid in capsular bags is sodium hyaluronate and that the distention is caused by aqueous humor being drawn into the capsular bag by an osmotic gradient across the capsule when the capsulorhexis diameter is smaller than that of the PC IOL and by viscoelastic material retained and trapped in the bag intraoperatively.

Aged↗
PubMed2000

Serum total bile acid level as a sensitive indicator of hepatic histological improvement in chronic hepatitis C patients responding to interferon treatment.

BACKGROUND AND METHODS: Serum total bile acid (TBA) levels are used clinically as a sensitive and reliable index of hepatobiliary diseases. In the present study, to assess the clinical usefulness of determining TBA in interferon (IFN)-treated patients, changes in liver function test values, including TBA and liver histology, were examined in 36 chronic hepatitis C patients for 3 years after a sustained response to IFN treatment. RESULTS: Alanine aminotransferase and gamma-glutamyl transpeptidase values significantly decreased during the period of IFN treatment compared to the same measures before IFN treatment. Albumin, cholinesterase, total cholesterol and platelet count values temporarily decreased during IFN treatment, then increased significantly and reached a plateau 6-12 months after the end of IFN treatment. The zinc sulphate turbidity test and TBA values began to decrease during IFN treatment and continued to decrease during the 3-year follow-up period. The histological activity index of the liver (Knodell's score) significantly decreased, whereas the staging score was unchanged 1 year after the end of IFN treatment. In patients who had a TBA value > 10 micromol/L before IFN treatment, a significant correlation was observed between the decrease of TBA and liver histology grading score. CONCLUSIONS: A decrease in serum TBA level reflected histological improvement in the liver more precisely than did changes in the other liver function test values following IFN therapy.

Adult↗
PubMed2000

Isolation of two different phenotypes of mycorrhizal mutants in the model legume plant Lotus japonicus after EMS-treatment.

Lotus japonicus has been proposed as a model plant for the molecular genetic study of plant-microbe interaction including Mesorhizobium loti and arbuscular mycorrhizal (AM) fungi. Non-mycorrhizal mutants of Lotus japonicus were screened from a collection of 12 mutants showing non-nodulating (Nod-), ineffectively nodulating (Fix-) and hypernodulating (Nod++) phenotypes with monogenic recessive inheritance induced by EMS (ethylmethane sulfonate) mutagenesis. Three mycorrhizal mutant lines showing highly reduced arbuscular mycorrhizal colonization were obtained. All of them were derived from Nod- phenotypes. In Ljsym72, the root colonization by Glomus sp. R-10 is characterized by poor development of the external mycelium, formation of extremely branched appressoria, and the blocking of hyphal penetration at the root epidermis. Neither arbuscules nor vesicles were formed in Ljsym72 roots. Fungal recognition on the root surface was strongly affected by the mutation in the LjSym72 gene. Unique characteristics in mutant lines Ljsym71-1 and Ljsym71-2 were the overproduction of deformed appressoria and arrested hyphal penetration of the exodermis. Small amounts of internal colonization including degenerated arbuscule formation occurred infrequently in these types of mutants. Not only fungal development on the root surface but also that in the root exodermis and cortex was affected by the mutation in LjSym71 gene. These mutants represent a key advance in molecular research on the AM symbiosis.

Ethyl Methanesulfonate↗
PubMed2000

The comparative effects of propofol versus thiopental on middle cerebral artery blood flow velocity during electroconvulsive therapy.

UNLABELLED: Electroconvulsive therapy provokes abrupt changes in both systemic and cerebral hemodynamics. An anesthetic that has a minor effect on cerebral hemodynamics might be more suitable for patients with intracranial complications, such as cerebral aneurysm. The purpose of our present study was to compare the effects of thiopental and propofol on cerebral blood flow velocity. We continuously compared cerebral blood flow velocity at the middle cerebral artery (MCA) during electroconvulsive therapy, using propofol (1 mg/kg, n = 20) versus thiopental (2 mg/kg, n = 20) anesthesia. Systemic hemodynamic variables and flow velocity at the MCA were measured until 10 min after the electrical shock. Heart rate and arterial blood pressure increased in the thiopental group until 5 min after the electrical shock. In the propofol group, an increase in mean blood pressure was observed to 1 min after the electrical shock. Mean flow velocity at the MCA decreased after anesthesia in both groups, and increased at 0.5-3 min after the electrical shock in the thiopental group and at 0.5 and 1 min after the shock in the propofol group. The flow velocities at 0.5-5 min after the electrical shock were significantly more rapid in the thiopental group compared with the propofol group. ¿abs¿ IMPLICATIONS: Cerebral blood flow velocity change, measured by transcranial Doppler sonography during electroconvulsive therapy, was minor using propofol anesthesia compared with barbiturate anesthesia. Propofol anesthesia may be suitable for patients who cannot tolerate abrupt cerebral hemodynamic change.

Adolescent↗
PubMed2000

[A recurrent case of amebic liver abscess seventeen years after the first occurrence].

A 49-year-old male who had been diagnosed as having amebic liver abscess when he was 32-year-old was admitted to our hospital with fever and watery diarrhea. Ultrasonography and CT examination demonstrated a solitary abscess in the right lobe of the liver. Cysts of Entamoeba histolytica were detected in the stool and an aspiration of the liver abscess looked like anchovy paste. Serum amebic antibody by the IFA method was positive and the case was diagnosed as amebic liver abscess. The patient was treated with metronidazole, and percutaneous transhepatic abscess drainage was performed. The liver abscess decreased remarkably in size and serum amebic antibody was negative after the treatment. Recurrence of amebic liver abscess is rare and we report this case with some literature.

Humans↗
PubMed2000

Identification of a compound in Chamaecyparis taiwanensis inhibiting the ice-nucleating activity of Pseudomonas fluorescens KUIN-1.

Inactivation of the ice-nucleating activity of Pseudomonas fluorescens KUIN-1 by compounds in the leaves from coniferous trees were investigated, and the inactivated material was identified. Intact cells of the strain KUIN-1 and the acetone or methanol extracts of leaves of various coniferous trees were allowed to react for 30 min at 18 degrees C. Antinucleation compounds were obtained from Chamaecyparis taiwanensis. When the acetone extract from the leaves of coniferous trees was added to the cell suspension (about 10(6) cells/ml) in 50 mM potassium phosphate buffer (pH 7.0), the ice nucleating temperature, T50, was significantly decreased (T50 < -5 degrees C). This inhibitor was isolated by using TLC, then identified as hinokitiol based on UV-VIS, IR, and mass spectral data. When intact cells of the strain KUIN-1 were incubated with hinokitiol, limonene, and alpha-pinene of the principal constituent of the leaves of coniferous trees in 50 mM potassium phosphate buffer (pH 7.0), the ice-nucleating activity decreased, but not in alpha-terpinene. Furthermore, the ice-nucleating activities from other ice-nucleating bacteria also decreased in the presence of hinokitiol. This inhibition was proportional to the concentration of hinokitinol. The pH and thermal stabilities of the ice-nucleating activity of the cells were changed by the addition of hinokitiol (10 mM).

Bicyclic Monoterpenes↗
PubMed2000

A cold acclimation protein with refolding activity on frozen denatured enzymes.

We found that a cold acclimation protein from an ice-nucleating bacterium, Patoea ananas KUIN-3, has refolding activity on frozen denatured protein. Based on a SDS-PAGE analysis, we confirmed that the cold shock-treated cells of strain KUIN-3 could produce some cold acclimation proteins that inhibit their syntheses by the addition of chloramphenicol during the cold acclimation. Among such proteins, Hsc25 had refolding activity similar to GroELS. Hsc25 was purified to apparent homogeneity by (NH4)2SO4 precipitation and some chromatographies. The purified Hsc25 was composed of 8 subunits of 25,000 each with a molecular mass of 200,000 and had refolding activity against denatured enzymes, which were denatured by heat-treatment at 100 degrees C, cryopreservation at -20 degrees C, or guanidine hydrochloride, in a manner similar to GroELS. The N-terminal sequence of Hsc25 was Met-Arg-Ala-Ser-Thr-Tyr-His-Ala-Ala-Arg-. Furthermore, Hsc25 had a high level of activity at low temperature (12 degrees C). Also, the dissociation constants, KD (M) as the binding specificity for enolase, mutarotase, isocitrate dehydrogenase, and lactate dehydrogenase were 1.82x10(-10), 4.35x10(-9), 8.98x10(-12), and 3.05x10(-11), respectively. The affinity of Hsc25 for frozen danatured enzymes was higher than the affinity for heat denatured enzymes when compared with the affinity of GroEL. These results are the first report on the characterization of a purified chaperon that was induced by cold acclimation.

Adaptation, Physiological↗
PubMed2000

Occupational asthma due to exposure to African cherry (Makore) wood dust.

A 35-year-old man who had been a carpenter and a cabinet worker for over 15 years, was referred to our clinic with a 4-month history of cough, chest tightness and difficulty in breathing which occurred within minutes of exposure to African cherry wood (Makore). He developed a dual asthmatic reaction on specific challenge test with an extract of African cherry wood dust. Thus, the diagnosis of occupational asthma due to exposure to African cherry wood dust was confirmed by the specific challenge test. The mechanism of asthma due to African cherry wood dust exposure is not clear.

Adult↗
PubMed2000

[Aortic valve replacement with a stentless porcine aortic root bioprosthesis].

From April, 1999 to November, 1999, 8 patients underwent the aortic valve replacement using Medtronic Freestyle aortic root bioprosthesis. Mean age was 67.8 years old. Aortic valve etiology was as follows, AS: 1 case, AR: 2 cases, ASR: 3 cases, IE: 1 case, mechanical valve malfunction due to subvalvular pannus: 1 case. The implanted valve size was 25: 2 cases, 23: 3 cases, 21: 1 cases, 19: 2 cases. Surgical technique was subcoronary: 7 cases, full-root: 1 case. Post-op 2D-echo revealed tribial aortic valve incompetence in two cases because of size discrepancy between the aortic annulus and the ascending aorta. Pacemaker implantation was needed in 1 case because of the complete A-V block. In comparison with 5 cases of aortic valve replacement with Hancock II performed in same period, there were no significant differences about the implanted valve size and mean systolic pressure gradient, but the effective orifice area in Freestyle cases was significantly larger than Hancock II cases.

Aged↗
PubMed2000

[Minimally invasive direct coronary artery bypass grafting using subxiphoid approach].

We report twelve cases of minimally invasive coronary artery bypass grafting via small laparotomy using right gastroepiploic artery (RGEA) to the right coronary artery. Seven patients were operated on without partial sternotomy (N group), and lower partial sternotomy with Octopus 2 stabilization system was used in five of the cases (P group). Postoperative Doppler echographic imaging or angiographic study showed all RGEA grafts were functioning well in P group. However, graft occlusion was observed in two of the cases in N group. Inferior partial sternotomy combined with Octopus 2 stabilization system produce a clear surgical view, which avoids of both full-sternotomy and cardiopulmonary bypass. This method might be useful especially for reoperation.

Aged↗
PubMed1999

Identification of a novel ice-nucleating bacterium of Antarctic origin and its ice nucleation properties.

A novel ice-nucleating bacterium (INB) was isolated from Ross Island, Antarctica. INBs could be isolated more frequently than was generally thought. INB strain IN-74 was found in the white colony group. Strain IN-74 was identified from its taxonomic characteristics as a novel INB, Pseudomonas antarctica IN-74. When strain IN-74 was cultured aerobically in a medium consisting of the ice-nucleating broth (pH 7.0) for 6 days at 4 degrees C, the ice-nucleating activity of strain IN-74 cells was obtained. Strain IN-74 cells produced ice nuclei only at extremely low growth temperatures. The nuclei appeared to be less thermolabile than those of INB Pseudomonas fluorescens KUIN-1. The freezing difference spectra in D2O and H2O at ice-nucleating temperature for strain IN-74 cells and conventional INBs (Pseudomonas fluorescens KUIN-1, Pseudomonas viridiflava KUIN-2, and Pseudomonas syringae C-9) exhibited different curves.

Antarctic Regions↗
PubMed1999

Epidural block with mepivacaine before surgery reduces long-term post-thoracotomy pain.

PURPOSE: To examine the effect of continuous epidural block initiated before thoracic surgery upon early and long-term postoperative pain. METHODS: In a double-blind study, 70 patients scheduled for thoracic surgery under general anesthesia were assigned randomly to receive continuous epidural block with mepivacaine 1.5% initiated either 20 min before surgical incision (Pre group) or at completion of surgery (Post group). In both groups the initial dose was 4 ml, followed by a continuous infusion at 4 ml x hr(-1) until 72 hr after operation. Indomethacin suppositories, 50 mg, were administered on request as supplementary analgesics. Visual analogue scale at rest was assessed four hours after operation, and then every 24 hr after operation on postoperative days 1 through 7, and also days 14 and 30. At three and six months after operation, all patients were interviewed by telephone with respect to postoperative pain. The most severe pain was assessed using modified numerical rating scale. RESULTS: By a visual analogue scale, postoperative pain was less in the Pre group than in the Post group at four hours, two and three days after operation (P < 0.05). By a numerical rating scale six months after operation, pain was less in the Pre group than in the Post group (P = 0.015). The percentage of pain-free patients was higher in the Pre group than in the Post group at three (P = 0.035) and six (P = 0.0086) months after operation. CONCLUSION: Continuous epidural block initiated prior to surgery may reduce long-term post-thoracotomy pain.

Anesthesia, Epidural↗
PubMed1999

Exposure and sensitization to cat dander: asthma and asthma-like symptoms among adults.

BACKGROUND: Several pets, such as cats, dogs, and rodents, are known to produce allergens. Despite the clinical and laboratory evidence that exposure to pets can cause bronchoconstriction in sensitized subjects, the results of population studies have been contradictory. OBJECTIVES: The purpose of this study was to investigate the relationship between cat ownership and the prevalence of asthma, asthma-like symptoms, and bronchitic symptoms among subjects 20 to 44 years of age in Vancouver, Canada and to determine whether sensitization is responsible for such an association. METHODS: Two thousand nine hundred ninety-nine (88%) randomly selected subjects responded to a mail questionnaire. Of these, 504 participated in laboratory examination, including allergy skin testing. RESULTS: One thousand nineteen study responders (34%) were pet owners at the time of the study (current owners). Current pet owners were found to have a higher prevalence of current asthma, asthma-like symptoms, and bronchitic symptoms compared with those without pets. Cat owners had significantly higher risk of having current asthma and asthma-like symptoms. In the subset who had allergic skin tests, we found that those who were allergic to cat dander had a significantly higher risk of current asthma than those not allergic to cat dander and not owning a cat. CONCLUSION: This study provides evidence that sensitization to cat dander is a more important risk factor for current asthma and asthma-like symptoms than cat ownership itself.

Adult↗