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Biomedical subjects

H Kurosawa

Publications and source records attributed to H Kurosawa.

At least 55 records · Page 3Linked to original sources
PubMed2001

Quantitative assessment of the pharyngeal airway by dynamic magnetic resonance imaging in obstructive sleep apnea syndrome.

Dynamic changes in the pharyngeal airway of patients with obstructive sleep apnea syndrome (OSAS) were evaluated by quantitating the findings of real-time imaging performed during wakefulness and spontaneous sleep by means of dynamic magnetic resonance imaging (MRI). Six patients with OSAS and 3 non-OSAS subjects, selected prospectively and randomly, underwent polysomnography and dynamic MRI. The cross-sectional areas of the soft palate and oropharynx and the anterior-posterior airway dimensions seen during wakefulness and spontaneous sleep were calculated by US National Institutes of Health imaging software. On the basis of a case control study, comparisons were made with age-matched and body mass index-matched obese non-OSAS snorers. Spontaneous sleep caused significant obstruction and narrowing of various sites of the pharyngeal airway in the OSAS patients, but not in the non-OSAS subjects. During wakefulness, the non-OSAS subjects showed no marked narrowing of the pharyngeal airways, whereas a transient but significant narrowing was observed in the OSAS patients. The mean values of both the cross-sectional area and the anterior-posterior diameter at the soft palate were significantly reduced by spontaneous sleep in the OSAS patients. Dynamic MRI in awake OSAS patients shows promise as a routine diagnostic tool for localizing the upper airway collapse for appropriate selection of surgical therapy.

Adult↗
PubMed2001

[Indications for and clinical outcome of the Ross procedure: a review].

The Ross procedure has been used increasingly to treat aortic valve disease in children and young adults. The primary indication for the Ross procedure is to provide a permanent valve replacement in children with congenital aortic stenosis. More recently, it has been extended to young adults with a bicuspid aortic valve and small aortic annulus, especially women wishing to have children. Other possible indications include complex left ventricular outflow obstructive disease, native or prosthetic valve endocarditis, and adult aortic insufficiency with a dilated aortic annulus. Conversely, Marfan syndrome is considered to an absolute contraindication, and this procedure should be used with caution in patients with rheumatic valve disease and a dysplastic dilated aortic root because of the higher associated incidence of autograft dysfunction. The technique of total aortic root replacement has become the preferred method of autograft implantation, because it carries the lowest risk of pulmonary autograft failure. In patients with marked graft-host size mismatch, either concomitant aortic annulus reduction and fixation or aortic annulus enlargement (i.e., the Ross-Konno procedure) should be performed. The Ross Procedure International Registry data document that in the modern era (post-1986) the early and late mortality rate is 2.5% and 1%, respectively. Excellent long-term results have been reported, and the benefits of this procedure include optimal hemodynamics, low risk of endocarditis, resistance to infection in patients with active endocarditis, and nonthrombogeneicity and therefore few anticoagulation-related complications. The Ross procedure can be performed with acceptable early and mid-term mortality and excellent autograft durability. Further long-term follow-up will confirm the role of this procedure in patients with various types of aortic valve disease.

Adult↗
PubMed2001

[Right ventricular outflow tract reconstruction with PTFE mono-cusped transannular patch for tetralogy of Fallot].

Conotruncal repair for tetralogy of Fallot consists of (1) precise closure of the VSD with the membranous flap and (2) reconstruction of the right ventricular outflow tract (RVOT) by a short transannular patch (< 30% of the RV length) with a wide PTFE monocusp. This report describes the mid-term results in 46 patients with tetralogy of Fallot who underwent conotruncal repair with PTFE monocusped transannular patch and have been followed up for 4 years or more. There was no early and late death and no patient required reoperation. No patient has had a significant residual defect or tricuspid regurgitation (> II). The right and left ventricular pressure ratio was 0.41 +/- 0.12 and the pressure gradient across RVOT was 10.5 +/- 5.9 mmHg, signifying sufficient relief of RVOT obstruction. The mobility of the PTFE monocusp was echocardiographically detected in 86% over a mean follow-up period of 84 +/- 34 months and % freedom from pulmonary regurgitation (> II) was 85.9% at 10 years postoperatively. Excellent long-term durability of the PTFE monocusp provided the normal right vent performance with RVEDV of 91.8 +/- 29.5% of normal and a central venous pressure of 5 +/- 1 mmHg. In conclusion, conotruncal repair with a wide and short transannular patch has provided good mid-term results with the excellent long-term durability of PTFE monocusp.

Adolescent↗
PubMed2001

[Double outlet right ventricle].

There are eight fundamental types of double-outlet right ventricle based on the ventriculoarterial relationship, deviation of the great artery, and atrioventricular relationship. Combination of the dextroposition of the posterior great artery and levoposition of the anterior great artery provides conotruncal criss-cross. The appropriate biventricular repair can be selected in the setting of two types of double outlet right ventricle, the dextroposition and conotruncal criss-cross type.

Double Outlet Right Ventricle↗
PubMed2001

Magnetic resonance imaging observation of the conus medullaris.

We examined the anatomical height and shape of the conus medullaris in 602 cases using magnetic resonance imaging. The peak of the distribution of the conus height was at the middle one-third of L1. The comparison of the conus level had no significant relationships with age or sex, but the juvenile group had more a caudal distribution of the conus level. The shape of the conus medullaris was classified into three types, and the type B was most frequently observed.

Adolescent↗
PubMed2000

Introduction of monosaccharides having functional groups onto a carbosilane dendrimer: a broadly applicable one-pot reaction in liquid ammonia involving Birch reduction and subsequent SN2 reaction.

Benzylthioalkyl glycosides of D-glucuronic acid, N-acetyl-D-glucosamine, and N-acetylneuraminic acid (common monosaccharide constituents of natural oligosaccharide chains) have been prepared as sulfide precursors for the carbohydrate coating of dendric carbosilane cores and used in a generally applicable one-pot reaction (Birch reduction in liquid ammonia and subsequent SN2 reaction) to generate a thioether linkage between the monosaccharide moieties and a carbosilane dendrimer. The dendrimers were uniformly functionalized with the monosaccharides in good yields.

Amides↗
PubMed2000

Polyurethane membrane as an efficient immobilization carrier for high-density culture of rat hepatocytes in the fixed-bed reactor.

A fixed-bed bioreactor with a polyurethane membrane (PUM) as a cell-supporting material was developed for high-density culture of rat hepatocytes. The PUM has a heterogeneous porous structure of micropores (pore size <100 microm) and macropores (pore size >100 microm) with a porosity of 90%. One important feature of a PUM is that the macropores have finger-like structures and their diameters gradually decrease from the upper to the lower layer of the PUM. Most rat hepatocytes were readily immobilized in the micropores of PUM. Immobilized cell densities of 1-3 x 10(7) cells/cm(3) PUM were achieved within 5 min by natural downflow of cell suspension and their immobilization efficiencies were more than 99%. Using a syringe pump, a cell density of 5 x 10(7) cells/cm(3) PUM was achieved with more than 96% immobilization efficiency. Perfusion cultures using this reactor were performed for 7 days without cell leakage. The optimal cell density for albumin secretion was between 2 x 10(7) and 3 x 10(7) cells/cm(3) PUM. Albumin secretion in the perfusion culture was maintained for a relatively long period of time when compared to that in the monolayer culture. The rate of albumin secretion in the perfusion culture was about 50% of that in monolayer culture. Hepatocytes immobilized in PUM were slightly aggregated, but they maintained spherical form individually even after 7 days of cultivation. The above results show that PUM is a promising cell-supporting material for efficient immobilization of high cell density of hepatocytes.

Albumins↗
PubMed2000

Identification of dipeptidyl peptidase III in human neutrophils.

We have found activity of dipeptidyl peptidase (DPP) III, one of the most important enkephalin-degrading enzymes in the central nervous system, in human neutrophils. HPLC analysis of the peptide fragments produced by treatment of leucine-enkephalin with isolated neutrophils in the presence of inhibitors of other enkephalin-degrading enzymes revealed that the enzyme in human neutrophils cleaved dipeptides from the NH(2) terminus of leucine-enkephalin, suggesting the presence of DPPIII activity in human neutrophils. Using a specific synthesized substrate and proteinase inhibitors, it was found that the neutrophils have 19.2 +/- 3.6 microM/h/5 x 10(6) cells of beta-naphthylamine for the enzyme. It was also confirmed that spinorphin and tynorphin, both reported to inhibit the activities of enkephalin-degrading enzymes, had potent inhibitory activities (IC(50): 4.0 and 0.029 microg/ml, respectively) against the enzyme. The presence of DPPIII activity in human neutrophils suggests that the biologically active peptides which are associated with enkephalin play a physiological role in regulating enkephalin or inflammatory mechanisms in peripheral tissues.

2-Naphthylamine↗
PubMed2000

Association of EXT1 and EXT2, hereditary multiple exostoses gene products, in Golgi apparatus.

We prepared the specific antibodies for EXT1 and EXT2, hereditary multiple exostoses (HME) gene products, and characterized their expression, subcellular localization, and protein association among EXT members. Biochemical analyses indicate that EXT1 and EXT2 can associate and form homo/hetero-oligomers in vivo with or without HME-linked mutations, EXT1 (R340C) and EXT2 (D227N), when exogenously expressed in COS-7 cells. An immunocytochemical analysis showed that both EXT1 and EXT2 localized in Golgi apparatus, irrespective of HME mutations. An immunohistochemical analysis on developing bones further showed that both EXT1 and EXT2 were concomitantly expressed in hypertrophic chondrocytes of forelimb bones from 1-day-old neonatal mouse, but down-regulated in maturing chondrocytes of developing cartilage from 21-day-old mouse. Taken together with the recent finding that EXTs encode for the glycosyltransferase required for the synthesis of heparan sulfate [Lind, T., Tufaro, F., McCormick, C., Lindahl, U., and Lindholt, K. (1998) J. Biol. Chem. 273, 26265-26268], our results implied a molecular basis that a HME-linked mutation found in EXT genes could interfere the physiological function(s) of EXT homo/hetero-oligomers as glycosyltransferases in the developing bones of HME patients.

Animals↗
PubMed2000

Local hemostatic effects of microcrystalline partially deacetylated chitin hydrochloride.

The hemostatic effects of microcrystalline partially deacetylated chitin hydrochloride (DAC-HCl) were compared with those of cotton and collagen hydrochloride (collagen-HCl). The DAC-HCl had excellent physical properties as a hemostatic agent such as its ability to absorb and retain blood. In canine blood it induced the release of substances involved in the process of platelet activation, such as beta-thromboglobulin and platelet factor 4, and it also had excellent hemoagglutinative properties. Moreover, in a hemostatic study on bleeding from cancellous bone in canines it exhibited a hemostatic effect comparable to that exhibited by collagen-HCl. Because it also has an intrinsic promotive effect on wound healing, chitin hydrochloride is considered to be a promising hemostatic material.

Animals↗
PubMed2000

Coupling of Alkynes on a Pd-Pd Bond to Generate an Electrophilic µ-Butenediylidene Moiety.

The first dipalladium µ-PPh(3) complex (1) was obtained by the facile loss of two CH(3)CN ligands from [Pd(2)(PPh(3))(2)(CH(3)CN)(4)](PF(6))(2) in CH(2)Cl(2). Coupling of p-tolylacetylene (p-TolC identical withCH) with 1 or its precusor afforded the µ-butenediylidene complex 2, treatment of which with CH(3)CN resulted in PPh(3) migration to give 3.

Journal Article↗
PubMed2000

Pulmonary atresia with intact ventricular septum, antegrade coronary-right ventricular sinusoidal communication, and Wolff-Parkinson-White syndrome.

A fenestrated Fontan operation was performed successfully in a patient with pulmonary atresia with intact ventricular septum, an antegrade sinusoidal communication, and Wolff-Parkinson-White syndrome. Unlike most cases, blood flow in the sinusoidal communication was antegrade, from the left anterior descending artery to the right ventricle. This is the first report of the combination of pulmonary atresia with intact ventricular septum and Wolff-Parkinson-White syndrome.

Child, Preschool↗
PubMed2000

Rotational acetabular osteotomy for severely dysplastic acetabulum.

The operative procedures chosen for arthrosis with severe acetabular dysplasia vary among orthopaedic surgeons. We operated on 250 hips using the rotational acetabular osteotomy (RAO) method of Ninomiya and Tagawa [8]. In this report, we describe the technique of RAO and the results of this procedure in patients with severely dysplastic hips. Among the 250 hips, there were 6 which were classified as Severin group V. In those hips, the CE angle was less than 0 degrees, and the femoral head showed superolateral subluxation. After acetabular osteotomy with straight and curved osteotomes, smooth inferolateral rotation could be done in all cases. At the latest follow-up symptoms were improved remarkably, especially pain. Radiographically, adequate coverage of the femoral head was achieved and joint congruence improved in all 6 hips.

Acetabulum↗
PubMed2000

Hypoplasia of bilateral humeral trochlea associated with bilateral ulnar nerve palsy.

We document a case of bilateral ulnar nerve palsy that developed in an 27-year-old Japanese man who had bilateral hypoplasia of the humeral trochlea. Surgical management produced good results regarding the ulnar nerve palsy. The pathogenesis of the nerve paresis in this particular condition is discussed. There have been no reports outside Japan. Whether this deformity occurs only in persons of Japanese extraction or is simply overlooked by foreign surgeons is an interesting question.

Adult↗
PubMed2000

Biological fixation of the graft within bone after anterior cruciate ligament reconstruction in rabbits: effects of the duration of postoperative immobilization.

To investigate the effects of the duration of postoperative immobilization on the biological fixation of the graft within bone after anterior cruciate ligament (ACL) reconstruction, we performed ACL reconstruction in 27 rabbits, which were divided into five groups - no immobilization and 1-, 2-, 4-, and 6-week immobilization. All animals were killed 6 weeks postoperatively, and the graft-bone tunnel interface was examined biomechanically and histologically. In the groups with immobilization, in tensile failure tests, most specimens failed through the intraarticular portion of the grafts. There was no significant difference in the maximum load between these groups. In the no-immobilization group, all specimens failed through pulling of the grafts out of the femoral tunnel, with a lower maximum load than in the other groups. Histologically, new bone formation and occasional collagen fiber continuity were observed at the interface; which consisted of a fibrous tissue. In the no-immobilization group, the graft was partly separated from the fibrous tissue covering the bony wall. It is concluded that no immobilization delays the biological fixation process in the bone tunnel after ACL reconstruction, and that a certain period of immobilization is necessary for the fixation to proceed smoothly.

Animals↗
PubMed2000

Abnormal lateral notch in knees with anterior cruciate ligament injury.

We reviewed plain radiograms of anterior cruciate ligament injuries to determine the frequency of an abnormal lateral notch found in the lateral femoral condyle, and we investigated a possible mechanism for its occurrence by determining the relationship with associated injuries. We analyzed data for 216 patients who underwent ACL reconstruction between 1993 and 1996, whose radiographic images of the contralateral knee were available. The numbers of male and female patients were 122 and 94, respectively, and their ages ranged from 14 to 47 years (average, 25 years). The abnormal notch visualized by lateral radiograph was found in 66 of 216 knees (30. 6%) and was classified into three types. The type of abnormal notch seen most frequently (73%) was located at the same site as the notch on the contralateral side, but appeared deeper than normal. Knees with abnormal notches showed lateral meniscal injuries more frequently than those without such notches (P<0.005). The abnormal notch was assumed to have formed at the time of injuries, after impingement of the lateral femoral condyle on the lateral tibial condyle. Cartilage damage at the abnormal notch should be carefully observed in the future.

Adolescent↗
PubMed2000

Reconstruction of rabbit Achilles tendon with three bioabsorbable materials: histological and biomechanical studies.

This study investigated whether three biodegradable materials, poly-N-acetyl-D-glucosamine (chitin), poly-epsilon-caprolactone (p-CL), polylactic acid (PLA), and chitin/p-CL composite could be used as scaffold implants in the reconstruction of extra-articular ligaments or tendons. Braided artificial tendons made from these materials were soaked in phosphate-buffered saline or implanted in the subcutaneous tissue of 31 Japanese white rabbits and then subjected to load at failure testing. There was no significant loss of load at failure when chitin tendons were soaked in saline for 26 weeks, but a rapid decrease occurred in vivo. The other two types of tendons showed significant loss of strength after 26 weeks both in vitro and in vivo. Another 111 rabbits were used to assess Achilles tendon reconstruction with the braided tendon implants. The tendon regeneration process was assessed macroscopically, histologically, immunohistochemically, and mechanically (maximum load at failure). Chitin showed more rapid degradation than the other materials on histological examination. There was good formation of fibrous tissue composed of type I and type III collagen around the chitin, PLA, and chitin/p-CL fibers in comparison with p-CL fibers, but chitin tendons showed more rapid loss of strength after implantation. Both PLA and the chitin/p-CL composite tendons had good initial strength and showed increased ingrowth of fibrous tissue, suggesting that these materials are promising as artificial tendons.

Achilles Tendon↗