Biomedical subjects
T Nakada
Publications and source records attributed to T Nakada.
Autoregulation of organ circulation. Artery dilatation theory on autoregulation.
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[Congenital heart diseases-cyanotic group].
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[2 cases of protein-losing gastroentropathy].
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[Experimental pulmonary reimplantation].
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Morphologic analysis of common atrioventricular valves in patients with right atrial isomerism.
The objective of the study was to examine the relation between the morphology of the common atrioventricular valve and regurgitation of the valve in patients with right atrial isomerism. We examined seven consecutive patients with documented right atrial isomerism who subsequently underwent postmortem examination during a 10-year period. The degree of regurgitation and the diameters of the common valve were evaluated via cineangiography, and the site of regurgitation was evaluated by echocardiography. The morphology of the common atrioventricular valve was assessed further at autopsy. Cineangiography revealed valve diameters ranging from 14.8 to 27.8 mm (mean 20.9 mm). Valvar regurgitation was revealed within 2 months of birth in all patients. Regurgitation abruptly worsened in three patients after placement of a Blalock-Taussig shunt or a central shunt and postintubation. Autopsies revealed that the common atrioventricular valve consisted of four leaflets in five patients, and three leaflets in two. The anterior leaflets were large and protruding in all patients, and the lateral leaflets were thickened in six. All patients had a mass consisting of the left lateral leaflets and chordae with direct attachment of the chordae to the ventricular muscle (the right lateral leaflet was attached to the ventricular muscle and immobile in one patient). The lateral leaflets clung to the ventricular wall and exhibited poor movement in six patients. Leaflets with poor mobility corresponded to the regurgitant valvar site as assessed by echocardiography in six patients; and the regurgitation in three patients with acute deterioration occurred at the valvar side with poor mobility. It is concluded that the common atrioventricular valve in patients with right atrial isomerism has morphologic characteristics that may be associated with valvar regurgitation and malignant potential for abrupt deterioration after replacement of systemic-pulmonary shunting.
19F 2-FDG NMR imaging of the brain in rat.
Images of the rat head reflecting glucose utilization were obtained using 2-fluoro-2-deoxy-D-glucose (2-FDG) and 19F nuclear magnetic resonance (NMR) imaging. Spatial heterogeneity of glucose utilization in the rat head was clearly demonstrated showing significantly higher glucose utilization in the brain as compared to the surrounding tissues. Although the potential adverse effects of the high doses of 2-FDG (400 mg/kg) needed to perform the study preclude immediate application of this technique to clinical quantitative glucose utilization studies, the present study shows potential for future development of glucose utilization imaging by NMR.
One-dimensional chemical shift imaging of fluorinated neuroleptics in rat brain in vivo by 19F NMR rotating frame zeugmatography.
One-dimensional chemical shift imaging reflecting local tissue contents of the fluorinated neuroleptics fluphenazine and trifluoperazine in rat brain was obtained noninvasively in vivo using one-dimensional 19-fluorine (19F) nuclear magnetic resonance (NMR) rotating frame zeugmatography. Activities of these fluorinated neuroleptics showed a differential distribution in the brain, maximal in the deep structures presumably within the basal ganglia. An additional resonance of an unidentified fluorinated metabolite was localized to the subcutaneous tissue. The present data indicate the feasibility of chemical shift imaging of fluorinated neuroleptics using a high field NMR system and the potential for future development of neurotransmitter imaging by NMR.
Reversible blindness associated with alcoholic ketoacidosis: pseudomethanol intoxication.
We report a case of reversible blindness associated with severe acidosis. A 49-year-old female presented with sudden onset of bilateral blindness. A work up for possible etiologic factors including computed tomography failed to reveal any abnormalities except for ethanol induced severe ketoacidosis. Methanol was not detectable in the serum despite an ethanol level of 14.76 mmol/L, effectively ruling out the diagnosis of methanol intoxication. Treatment of the acidosis led to rapid resolution of her blindness. Review of the literature revealed two case reports of reversible blindness associated with severe acidosis in diabetics. The current case underscores the necessity for a clear understanding of the role of severe acidosis as the sole causative factor of reversible bilateral blindness.
Acute effects of tumor necrosis factor-alpha on testicular germ cell apoptosis and vascular neutrophil adhesion in rats.
Acute effects of tumor necrosis factor-alpha (TNF-alpha) on testicular germ cell apoptosis and vascular neutrophil adhesion were investigated in rats. Acute administration of TNF-alpha did not show a significant increase in percentage of apoptotic tubules and apoptotic germ cells. TNF-alpha administration did not enhance neutrophil adhesion score in the intertubular and subtunical vein. TNF-alpha does not acutely influence testicular germ cell apoptosis and vascular neutrophil adhesion in rats.
The use of ebastine, a mast cell blocker, for treatment of oligozoospermia.
The effect of mast cell blocker (ebastine) on semen quality was evaluated in 15 idiopathic oligozoospermic males. Ten milligrams/day of ebastine was administered orally for 3 months. Nine cases (66.7%) showed definite improvement in the semen quality. The wives of 3 patients (20%) became pregnant within 6 months of the initial treatment. It would appear that mast cell blocker (ebastine) significantly improves semen quality in men with idiopathic oligozoospermia.
Localization of the sex-determining region-Y gene in XX males.
Localization of the sex-determining region Y (SRY) was investigated in 2 XX males. Metaphase chromosomes from peripheral lymphocytes were stained by fluorescence in situ hybridization using DXZ1 and SRY probes. An identical hybridization signal with the SRY probe was found on an X chromosome in both cases. The karyotype of the 2 cases was 46,XX, t(X;Y)(p22.3;p11.3). It would appear that XX male is the presence of a Y-chromosome fragment transferred to the X-chromosome short arm by unequal interchange between homologous regions in the short arms of sex chromosomes.
Absence of Y chromosome microdeletions involving the DAZ (deleted in azoospermia) and RBM (ribonucleic acid-binding motif) genes in patients with chordee without hypospadias.
The presence or absence of 33 DNA loci was investigated with a focus on the long arm of Y chromosome (Yq) interval 6 involving the DAZ and RBM genes, by means of a polymerase chain reaction strategy, in 10 patients with hypospadias. All patients did not show any of the 33 DNA loci. It would appear that chordee without hypospadias does not involve interval 6 of the Y chromosome.
Detection of chromosome 15 deletion in Prader-Willi syndrome using fluorescence in situ hybridization.
Deletion of chromosome 15 was investigated in 6 patients with Prader-Willi syndrome (PWS) using chromosome and fluorescence in situ hybridization (FISH) analysis. Although chromosome analysis using G-banding methods revealed the deletion of 15q11-q13 in only 3 cases, staining by FISH using D15S11 and/or small nuclear ribonucleoprotein polypeptide N (SNRPN) probes detected chromosome 15 deletion in all cases. It would appear that FISH analysis is an effective diagnostic test for the detection of chromosome 15 deletion in patients with PWS.
Application of ICSI for cryptorchid therapy.
Recent advances are provided in assisted reproductive technology and application of ICSI as treatment for infertile patients with previous cryptorchidism. Fertility rates were 25-81% and 8-48% in patients with unilateral and bilateral cryptorchidism, respectively. With the advent of assisted reproductive technology, pregnancy was not possible without sperm. Research in humans has resulted in pregnancy and live births after the injection of haploid germ cells (round spermatids) into the oocytes. In the mouse tetraploid germ cells (primary spermatocytes), nuclei have been injected into oocytes, which undergo meiosis, forming an embryo and live young. In animal models, round spermatids from both cryptorchid and previously cryptorchid testes can initiate normal embryo development when injected into mature oocytes. These cells may be used as substitutes for mature sperm. However, cryptorchidism in humans is often associated with inherent defects of spermatogenesis. With successive breakthroughs in treatment of impaired fertility associated with cryptorchidism, there is an increased risk of genetic abnormalities in the progeny. It is incumbent on clinicians who are involved in reproductive medicine to proceed cautiously with the development and application of assisted reproductive techniques to avoid creating future generations of genetically abnormal individuals.
Laparoscopic varicocelectomy in adolescents using an ultrasonically activated scalpel.
Ten laparoscopic varicocelectomies were performed using an ultrasonically activated scalpel to divide spermatic vessels in adolescents. The mean operation time was 35 (25-46) min. There were no intraabdominal viscelar or vascular complications, and no postoperative analgesia was required. These findings suggest that laparoscopic varicocelectomy using an ultrasonically activated scalpel may be a valuable treatment in the adolescent.
Sutureless vasovasostomy using new vascular closure staples in rats.
To evaluate the efficacy of sutureless vasovasostomy using vascular closure staples, 20 male Sprague-Dawley rats were used for the study. In each rat, a sutureless vasovasostomy using vascular closure staples was performed on a randomly selected side, and a conventional end-to-end microsutured anastomosis was performed on the opposite side. Operation time was significantly shorter for sutureless vasovasostomy using vascular staples (p < .001). Four weeks after the surgery, however, patency rate and granuloma formation were not different for conventional end-to-end vasovasostomy vs. sutureless vasovasostomy. These findings suggest that sutureless vasovasostomy is simple to perform and requires fewer special technical skills. This procedure may provide an alternative to the conventional vasovasostomy.
Reevaluation of testicular biopsies of males with nonobstructive azoospermia in assisted reproductive technology.
Spermatogenesis was investigated in seminiferous tubules of 100 males with nonobstructive azoospermia. Forty-four (44%) cases had Sertoli-cell-only syndrome, 23 (23%) had spermatogonium in the tubules, 17 (17%) had primary spermatocyte in the tubules, and 16 (16%) had round or late spermatid in the tubules. No cases showed secondary spermatocyte present in the tubules. The mean serum follicle-stimulating hormone (FSH) in males with nonobstructive azoospermia was significantly higher than that in males with obstructive azoospermia (p < .001). The mean concentrations of serum FSH in cases with Sertoli-cell-only syndrome and spermatogonium in the tubules were significantly higher than those in cases with primary spermatocyte and spermatid in the tubules (p < .05-.001). The results indicate that the evaluation of testicular histology using the type of germ cells present in seminiferous tubules is available for assisted reproductive technology.