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Biomedical subjects

H Kawabata

Publications and source records attributed to H Kawabata.

At least 37 records · Page 2Linked to original sources
PubMed2001

Connectivity perception of partly occluded gratings in 4-month-old infants.

Four groups of eight 4-month-old infants were each habituated to one of four displays consisting of a grating of either low (0.4 cycle deg(-1) or high (1.2 cycles deg(-1) spatial frequency, whose central portion was covered up with a horizontal occluder which was either narrow (1.33 deg) or broad (4.17 deg). Posthabituation displays consisted of a complete grating of the same frequency as the habituated grating, along with a separate grating whose central portion was replaced with a black gap of the same height as the occluder in the habituation displays. All the infants, except those who were habituated to the high frequency with the broad occluder, looked longer at the separate grating than the complete grating display during posthabituation trials. Previously, we found that infants under 1 month of age perceive the grating continuation only when the occluder height is less than about 0.5 cycle of the grating; our present results show that this figure increases to about 1.6 cycles of the grating frequency in the case of 4-month-old infants. These findings indicate that those developmental changes depend on both the sufficiency of visual information available and the efficiency of the perceptual ability of infants for grasping spatial relationships.

Analysis of Variance↗
PubMed2001

Western blot analysis for diagnosis of Lyme disease in acute facial palsy.

BACKGROUND: Lyme borreliosis has been implicated in the pathogenesis of acute peripheral facial palsy (APFP). Few studies, however, have used Western blot analyses to confirm the serological diagnosis. PURPOSE: To analyze the prevalence of anti-Borrelia antibodies in patients with APFP compared with healthy control subjects living in Hokkaido Island, Japan. PATIENTS AND METHODS: In total, 113 patients with APFP were analyzed. They included 32 patients with varicella zoster virus (VZV) reactivation (Ramsay Hunt syndrome and zoster sine herpete) and 81 patients with Bell's palsy. Fifty-eight healthy control subjects were also included. IgM and IgG antibodies to Borrelia garinii and afzelii were tested by Western blot, and diagnoses were made according to the Centers for Disease Control and Prevention criteria. RESULTS: Five of 81 (6.2%) patients with Bell's palsy, 1 of 32 (3.1%) patients with VZV reactivation, and 1 of 58 control subjects (1.7%) were judged to have both IgM and IgG antibodies to Borrelia. This difference was not significant (P >.05, chi2 test). Patients with Bell's palsy who had herpes simplex virus type 1 (HSV-1) reactivation at the onset of palsy had a higher IgM-immunoreactivity to Borrelia afzelii. CONCLUSIONS: Although it is one of the endemic areas of Lyme disease in Japan, the prevalence of APFP caused by Lyme borreliosis is low in Hokkaido Island. In addition, cross-reactivity to B. afzelii in IgM blots is often observed in patients with HSV-1 reactivation, suggesting that careful interpretation of Borrelia IgM immunoblot data are needed for accurate serological diagnosis.

Acute Disease↗
PubMed2001

flaB-polymerase chain reaction (flaB-PCR) and its restriction fragment length polymorphism (RFLP) analysis are an efficient tool for detection and identification of Leptospira spp.

For establishment of a rapid-identification method of Leptospira species, a flaB gene of Leptospira was investigated and the following results were obtained. 1) HaeIII- or HindIII-restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) products (793 bp) of flaB gene was effectual for the classification of species of Leptospira. 2) Twenty cells of Leptospira in 1 ml of coagulated blood and 100 cells of Leptospira in 1 ml of anti-coagulated blood could be detected by flaB-PCR. These results suggested that PCR-RFLP based on the flaB gene was an efficient tool for rapid detection and identification of species of infected Leptospira from clinical specimens.

DNA Primers↗
PubMed2001

Magnetic resonance angiography of the forearm and hand in children.

A two-dimensional time-of-flight magnetic resonance angiography was performed in 29 arms in 25 pediatric patients with congenital hand abnormalities, whose average age was three years and eight months. Venous structures were eliminated with presaturation technique and the remaining arterial system was evaluated. Magnetic resonance angiography demonstrated major arteries in the forearm well but not their branches. Even the biggest branch of the artery sometimes could not be detected. Magnetic resonance angiography and Allen test were consistent in determining patency of the palmar arch in 62% of the cases but the sensitivity was only 28%. Our experience showed that non-invasive, convenient, two-dimensional time-of-flight magnetic resonance angiography was useful for detecting continuity and spatial localisation of the major arteries in a child's forearm. However, it was not a complete alternative to conventional angiography and was unsatisfactory in delineating the vascular anatomy in the hand.

Adolescent↗
PubMed2001

Role of cardiac ATP-sensitive K+ channels induced by angiotensin II type 1 receptor antagonist on metabolism, contraction and relaxation in ischemia-reperfused rabbit heart.

The role of cardiac adenosine triphosphate-sensitive K+ (K(ATP)) channels induced by angiotensin II type 1 (AT1) receptor antagonist, CV-11974, on myocardial metabolism and contraction during ischemia, and reperfusion by the phosphorus 31-nuclear magnetic resonance in Langendorff-perfused rabbit hearts was investigated. After 20 min of continuous normothermic global ischemia, 30 min of postischemic reperfusion was carried out. CV-11974 with or without the K(ATP) channel blocker, glibenclamide, or the bradykinin B2 receptor antagonist, D-Arg-[Hyp3,D-Phe7]bradykinin, was administered 40 min prior to the global ischemia. Adenosine triphosphate (ATP), creatine phosphate (PCr), inorganic phosphate (Pi), intracellular pH (pHi), left ventricular systolic developed pressure, left ventricular end-diastolic pressure (LVEDP), and coronary flow were measured. Twenty-eight hearts were divided into 4 experimental groups consisting of 7 hearts each. Group I consisted of controls, Group II perfused with CV-11974 (10(-6) mol/L), Group III perfused with CV-11974 (10(-6) mol/L) in combination with glibenclamide (10(-6) mol/L), and Group IV perfused with CV-11974 (10(-6) mol/L) in combination with D-Arg-[Hyp3,D-Phe7]bradykinin (10(-6) mol/L). Group II showed a significant inhibition of the decrease in ATP during ischemia and reperfusion compared with Group I (p<0.01), being 42+/-3% and 19+/-4% at ischemia, 69+/-3% and 47+/-4% at reperfusion in Group II and Group I, respectively. Group II also showed a significant inhibition of the increase in LVEDP during ischemia and reperfusion compared with Group I (p<0.01), being 13+/-4 mmHg and 52+/-8 mmHg at ischemia, 8+/-2 mmHg and 26+/-5 mmHg at reperfusion in Group II and Group I, respectively. However, Group II did not inhibit the decrease in ATP and the increase in LVEDP during ischemia and reperfusion. Group IV also showed no inhibition of the aforementioned parameters during the same period. These results suggest that CV-11974 has a significant beneficial effect for improving myocardial energy metabolism and relaxation during both myocardial ischemia and reperfusion, which is provided by K(ATP) channels and bradykinin B2 receptor. The cardioprotective quality of the AT1 receptor antagonist is caused by the K(ATP) channels that are mediated by the bradykinin B2 receptor.

Angiotensin Receptor Antagonists↗
PubMed2001

Cardioprotection with angiotensin converting enzyme inhibitor and angiotensin II type 1 receptor antagonist is not abolished by nitric oxide synthase inhibitor in ischemia-reperfused rabbit hearts.

Although angiotensin converting enzyme (ACE) inhibitor and/or angiotensin II type 1 (AT1) receptor antagonist can protect the myocardium against ischemia-reperfusion injury, the mechanisms of the effect have not yet been characterized at the cellular level. We here examined the effect of the combination of an ACE inhibitor, temocaprilat, an AT1 receptor antagonist, CV-11974 and/or a nitric oxide synthase inhibitor, L-NAME, on the myocardial metabolism and contraction during ischemia and reperfusion by using phosphorus 31-nuclear magnetic resonance (31P-NMR) in Langendorff rabbit hearts. After normothermic 20 min global ischemia, postischemic reperfusion of 30 min was carried out. Twenty-one hearts were divided into three experimental groups consisting of 7 hearts each: a Tem+CV group perfused with a combination of temocaprilat and CV-11974; a Tem+CV+L-NAME group perfused with a combination of temocaprilat and CV-11974 plus L-NAME, and a control group. During ischemia, both the Tem+CV group and Tem+CV+L-NAME group showed a significant inhibition of the decrease in adenosine triphosphate (ATP) compared with the control group (p<0.01); the increase in ATP was 50+/-3%, 42+/-4%, and 19+/-4% in the Tem+CV group, Tem+CV+L-NAME group, and control group, respectively. Both experimental groups also showed a significant inhibition of the increase in left ventricular end-diastolic pressure (LVEDP) compared with the control group (p<0.01). After postischemic reperfusion, the Tem+CV group and Tem+CV+L-NAME group again showed a significant improvement of ATP as compared with the control group (p<0.01); the increase in ATP was 73+/-3%, 64+/-3%, and 47+/-4% in the Tem+CV group, Tem+CV+L-NAME group, and control group, respectively, and a significant decrease of LVEDP as compared with the control group (p<0.01). There were no differences in ATP, or LVEDP during ischemia and reperfusion between the Tem+CV group and Tem+CV+ L-NAME group. In conclusion, the combination of temocaprilat and CV-11974 showed significant potential for improving myocardial energy metabolism and relaxation during both myocardial ischemia and reperfusion. This beneficial effect was not dependent on NO synthase.

Angiotensin Receptor Antagonists↗
PubMed2001

Role of cardiac ATP-sensitive K+ channels induced by HMG CoA reductase inhibitor in ischemic rabbit hearts.

Although 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors can protect the myocardium against ischemic injury, the mechanisms of their effect have not yet been characterized at the cellular level. Therefore, we investigated the role of cardiac ATP-sensitive K+ (K(ATP)) channels induced by the HMG-CoA reductase inhibitor known as pravastatin on the myocardial metabolism during ischemia by phosphorus 31-nuclear magnetic resonance (31P-NMR) in isolated rabbit hearts. Forty-five min of continuous normothermic global ischemia was carried out. Pravastatin with or without the K(ATP) channel blocker glibenclamide or the nitric oxide synthase inhibitor L-NAME was administered beginning 60 min prior to the global ischemia. Twenty-eight hearts were divided into 4 experimental groups consisting of 7 hearts each: the control group, the P group consisting of pravastatin treatment, the P+G group consisting of pravastatin treatment with glibenclamide, and the P+L group consisting of pravastatin treatment with L-NAME. During ischemia, the decreases in adenosine triphosphate (ATP) and intracellular pH (pHi) were significantly inhibited in the P group in comparison with Control group (at end of ischemia, respectively; both p<0.01), as was the increase in inorganic phosphate (Pi) (at end of ischemia, p<0.01). However, the decreases in ATP and pHi and the increase in Pi were not inhibited in the P+G group during ischemia. The P+L group also showed no inhibition of the aforementioned parameters during the same period. These results suggest that pravastatin has a significant beneficial effect for improving the myocardial energy metabolism, which is provided by K(ATP) channels and nitric oxide (NO), during myocardial ischemia. The cardioprotection of HMG-CoA reductase inhibitor may be caused by the K(ATP) channels that are mediated by the NO.

Adenosine Triphosphate↗
PubMed2001

Use of intercostal nerves for neurotization of the musculocutaneous nerve in infants with birth-related brachial plexus palsy.

OBJECT: The use of intercostal nerves (ICNs) for the neurotization of the musculocutaneous nerve (MCN) in adult patients with traumatic brachial plexus palsy has been well described. However, its use for brachial plexus palsy in infants has rarely been reported. The authors surgically created 31 ICN-MCN communications for birth-related brachial plexus palsy and present the surgical results. METHODS: Thirty-one neurotizations of the MCN, performed using ICNs, were conducted in 30 patients with birth-related brachial plexus palsy. In most cases other procedures were combined to reconstruct all upper-extremity function. The mean patient age at surgery was 5.8 months and the mean follow-up period was 5.2 years. Intercostal nerves were transected 1 cm distal to the mammary line and their stumps were transferred to the axilla, where they were coapted directly to the MCN. Two ICNs were used in 26 cases and three ICNs in five cases. The power of the biceps muscle of the arm was rated Grade M4 in 26 (84%) of 31 patients. In the 12 patients who underwent surgery when they were younger than 5 months of age, all exhibited a grade of M4 (100%) in their biceps muscle power. These results are better than those previously reported in adults. CONCLUSIONS: Neurotization of the MCN by surgically connecting ICNs is a safe, reliable, and effective procedure for reconstruction of the brachial plexus in patients suffering from birth-related palsy.

Axilla↗
PubMed2001

Effect of myopia on frequency-doubling perimetry.

PURPOSE: To examine the effect of myopia, occasionally associated with glaucomatous eyes, on the results obtained by frequency-doubling perimetry (FDP). METHODS: Sixty emmetropic or myopic normal volunteers (mean age, 26.2 +/- 0.35 years, mean +/- SEM; range, 19-34) with good visual acuity and without glaucoma were divided into three groups. The groups were emmetropia to low-myopia (mean refractive error, -1.16 +/- 0.23 D), intermediate-myopia (-4.95 +/- 0.17 D), and high-myopia (-8.12 +/- 0.36 D; n = 20 each). All subjects were tested on the FDP full-threshold C-20 program and the Humphrey Field Analyzer (HFA; Humphrey, Dublin, CA) full-threshold program on one randomly selected eye. FDP and the HFA test were conducted with the subjects wearing their full distance correction and with their distance correction with appropriate additional correction for near, respectively. The calculated mean sensitivity (MS), mean deviation (MD), pattern standard deviation (PSD), and test durations for FDP and the HFA test for the three groups were compared using one-way analysis of variance. The relationship between the refractive error and MS, MD, or PSD was also analyzed by simple regression analysis. RESULTS: The MS and MD for the fields determined by the HFA decreased significantly as the refractive errors increased, but there were no significant differences in the MS, MD, and PSD for FDP between the three groups. There were no significant differences in the test durations between the three groups for both FDP and HFA testing. The refractive error was correlated with both MS and MD only for the fields determined by the HFA. CONCLUSIONS: The results showed that lens-corrected myopia does not alter the visual fields obtained by FDP, and FDP can therefore be used regardless of the presence of myopia.

Adult↗
PubMed2001

[A case of Sjögren's syndrome with dermatomyositis who died of rapidly progressive interstitial pneumonia].

We report a case of 55 year-old woman with six year history of Sjögren's syndrome developed fatal rapidly progressive interstitial pneumonia. She had been well until February 1999. She developed swelling and erythematous lesions in the cheek and hands in spring 1999. She was admitted to our hospital for investigations of skin lesions in May 1999. Physical examination on admission revealed small hemorrhagic lesions in the nailfold. Serum CK level was slightly elevated. Electromyogram and MRI suggested mild myositis in the proximal upper extremities. She was suspected to have dermatomyositis along with Sjögren's syndrome. Prednisolone 10 mg/day had been given for her skin problems since March 1999. Suddenly, dyspnea on exertion was appeared on 34th day of admission. Chest X-ray film showed an acute worsening of interstitial pneumonia. Methylprednisolone pulse therapy (1000 mg for 3 days) and cyclophosphamide pulse therapy (500 mg for a day) were started, and she was subsequently treated with 60 mg/day of prednisolone and 250 mg/day of Cyclosporin A. However, interstitial pneumonia did not respond to the treatment, and pneumomediastinum and pneumothorax have developed. She died of respiratory failure on 55th day. We consider that most likely explanation for fatal interstitial pneumonia is concomitantly occurred dermatomyositis.

Cyclophosphamide↗
PubMed2000

Transferrin receptor 2-alpha supports cell growth both in iron-chelated cultured cells and in vivo.

In most cells, transferrin receptor (TfR1)-mediated endocytosis is a major pathway for cellular iron uptake. We recently cloned the human transferrin receptor 2 (TfR2) gene, which encodes a second receptor for transferrin (Kawabata, H., Yang, R., Hirama, T., Vuong, P. T., Kawano, S., Gombart, A. F., and Koeffler, H. P. (1999) J. Biol. Chem. 274, 20826-20832). In the present study, the regulation of TfR2 expression and function was investigated. A select Chinese hamster ovary (CHO)-TRVb cell line that does not express either TfR1 or TfR2 was stably transfected with either TfR1 or TfR2-alpha cDNA. TfR2-alpha-expressing cells had considerably lower affinity for holotransferrin when compared with TfR1-expressing CHO cells. Interestingly, in contrast to TfR1, expression of TfR2 mRNA in K562 cells was not up-regulated by desferrioxamine (DFO), a cell membrane-permeable iron chelator. In MG63 cells, expression of TfR2 mRNA was regulated in the cell cycle with the highest expression in late G(1) phase and no expression in G(0)/G(1). DFO reduced cell proliferation and DNA synthesis of CHO-TRVb control cells, whereas it had little effect on TfR2-alpha-expressing CHO cells when measured by clonogenic and cell cycle analysis. In addition, CHO cells that express TfR2-alpha developed into tumors in nude mice whereas CHO control cells did not. In conclusion, TfR2 expression may be regulated by the cell cycle rather than cellular iron status and may support cell growth both in vitro and in vivo.

Animals↗
PubMed2000

[Humeral lengthening and deformity correction].

Nine patients with achondroplasia and one patient with Apert syndrome underwent the surgical lengthening of both humerus and simultaneous correction of both associated bone deformity. An unilateral external fixator was applied to the lateral aspect of the humerus with four half-pins and percutaneous predrilling osteotomy was performed at the apex of flexion deformity of the bone. During the waiting period before distraction, the flexion deformity of the distal humerus was corrected using an additional external fixator. Slow gradual distraction was subsequently carried out at a rate of 0. 25 mm every 6 hours. The average lengthening was 8 cm (range 7.5 to 9 cm), the overall treatment time 312 days (range 192 to 406 days), and the average healing index 39.0 days/cm. The average correction of the elbow flexion deformity was 20 degrees. We believe this treatment is useful to improve the function of the arms and the activity of daily living for the patients with bilateral short humeri.

Achondroplasia↗
PubMed2000

A technique of percutaneous multidrilling osteotomy for limb lengthening and deformity correction.

We have recently developed a technique of per-cutaneous multidrilling osteotomy for limb lengthening and deformity correction. The bone is drilled percutaneously, using a special drill guide, and osteotomy is accomplished by connecting the multiple drill holes with a small chisel. The bone segments are subjected to slow progressive distraction with an external fixation device. We have lengthened 33 limbs in 22 patients with congenital or post-traumatic limb shortening and/or bone deformities. All the patients underwent the proposed lengthening and/or correction of the bone deformities through a single-treatment procedure. None of the lengthened segments resulted in nonunion. This technique can prevent undesirable bone cracks and preserve soft tissue around the osteotomy site, and is also applicable to other fields of orthopedic surgery.

Adolescent↗
PubMed2000

A novel type X collagen gene mutation (G595R) associated with Schmid-type metaphyseal chondrodysplasia.

Metaphyseal chondrodysplasia of the Schmid type (MCDS) is a skeletal dysplasia affecting the long bone metaphyses; it is characterized by short stature, bowlegs, and coxa vara. The spine is generally not involved. Here we report a novel missense mutation of the type X collagen gene in a sporadic case of MCDS. The mutation was a heterozygous single base-pair transition of G-to-A at nucleotide 1783, which predicted a substitution of glycine by arginine at codon 595 (G595R) in the carboxyl-terminal noncollagenous domain. Interestingly, another mutation of the same codon, in which glycine is substituted by glutamic acid (G595E), was previously reported to cause spondylometaphyseal dysplasia (SMD), another group of skeletal dysplasias with involvement of the spine in addition to the long tubular bones. The novel G595R mutation identified in the present study supports the concept of type X collagenopathy.

Adolescent↗