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Biomedical subjects

M Nakazawa

Publications and source records attributed to M Nakazawa.

At least 127 records · Page 7Linked to original sources

Arrestin gene mutations in autosomal recessive retinitis pigmentosa.

OBJECTIVE: To assess the clinical and molecular genetic studies of patients with autosomal recessive retinitis pigmentosa associated with a mutation in the arrestin gene. DESIGN: Results of molecular genetic screening and case reports with DNA analysis and clinical features. SETTING: University medical center. PATIENTS: One hundred twenty anamnestically unrelated patients with autosomal recessive retinitis pigmentosa. METHODS: DNA analysis was performed by single strand conformation polymorphism followed by nucleotide sequencing to search for a mutation in exon 11 of the arrestin gene. Clinical features were characterized by visual acuity slitlamp biomicroscopy, fundus examinations, fluorescein angiography, kinetic visual field testing, and electroretinography. RESULTS: We identified 3 unrelated patients with retinitis pigmentosa associated with a homozygous 1-base-pair deletion mutation in codon 309 of the arrestin gene designated as 1147delA. All 3 patients showed pigmentary retinal degeneration in the midperipheral area with or without macular involvement. Patient 1 had a sibling with Oguchi disease associated with the same mutation. Patient 2 demonstrated pigmentary retinal degeneration associated with a golden-yellow reflex in the peripheral fundus. Patients 1 and 3 showed features of retinitis pigmentosa without the golden-yellow fundus reflex. CONCLUSIONS: Although the arrestin 1147delA has been known as a frequent cause of Oguchi disease, this mutation also may be related to the pathogenesis of autosomal recessive retinitis pigmentosa. This phenomenon may provide evidence of variable expressivity of the mutation in the arrestin gene.

Adult↗

Situs variation and cardiovascular anomalies in the transgenic mouse insertional mutation, inv.

The inv mouse was reported as a novel strain with situs inversus Yokoyama et al., '93), and a few cases with heterotaxy were found in homozygotes. The original report by Yokoyama et al. described the location of the heart and the stomach using the index of arrangement of body structure. We newly examined 40 homozygous offspring for phenotypes of visceroatrial situs and the incidence of cardiovascular anomalies making use of morphological details defined in each organ structure. According to the arrangement of each organ, which ranged from the almost complete form of situs inversus to left isomerism, visceroatrial situs was classified into four categories: Situs inversus (4 cases), "variation type" of situs (17 cases), "abdominal heterotaxy" (15 cases), and visceroatrial heterotaxy (4 cases). In offspring with situs inversus, only one had aortic stenosis (25%). Seven with the "variation type" of situs had cardiovascular anomalies, such as aortic stenosis, endocardial cushion defect, and posterior vena cava interruption (41%). All 15 offspring with "abdominal heterotaxy" had anomalies of the posterior vena cava, and three of them also had tetralogy of Fallot. The remaining four with visceroatrial heterotaxy had endocardial cushion defect, which was associated with outflow tract anomaly in two cases (i.e. tetralogy of Fallot in one case and transportation of the great arteries in the other). These results revealed that visceroatrial heterotaxy frequently occurred in the inv homozygotes, especially in the abdomen, and often showed a propensity to left isomerism with posterior vena cava interruption.

Animals↗

Anomalous looping, atrioventricular cushion dysplasia, and unilateral ventricular hypoplasia in the mouse embryos with right isomerism induced by retinoic acid.

BACKGROUND: Visceroatrial heterotaxy syndrome is characterized by abnormality of visceral laterality and complex cardiovascular anomalies usually involving both the outflow and inflow tract. Morishima et al. (1995) showed that mouse embryos treated with all-trans retinoic acid at embryonic day 6.5 (primitive streak stage) induces this syndrome. METHODS: To investigate the morphogenetic process of visceroatrial heterotaxy syndrome, we examined retinoic acid-treated mouse embryos at embryonic days 9-15 using scanning electron microscopy. RESULTS: The sinoatrial connection was first distinguished for the determination of situs as early as at embryonic day 10.5. Normal visceroatrial situs was found in 57% of all treated embryos, and the rest had abnormal situs, in which right isomerism was found in 81%. In the right-isomeric mouse, the cardiac morphology was characterized by abnormal looping together with dysplasia of the inflow and outflow tract cushion; that is, the primitive right ventricle was usually deviated cranially to various degrees, the atrioventricular cushion appeared trilobed in a half of them, and unilateral ventricular hypoplasia was noted in about one-third of them after embryonic day 14.5. CONCLUSIONS: An anomalous relation between the atrioventricular cushions and the interventricular septum appeared to have caused a restrictive inflow to the unilateral ventricle, leading to ventricular chamber hypoplasia on the ipsilateral side. Thus, we clarified that retinoic-acid treatment at the primitive streak stage disturbed cardiac looping and formation of atrioventricular cushion development, which secondarily influenced ventricular chamber development.

Abnormalities, Drug-Induced↗

Radiofrequency pulmonary valvotomy using a new 2-French catheter.

We report the usefulness of a new 2-French (F) electrode catheter for perforating the atretic pulmonary valve in patients with pulmonary atresia and intact ventricular septum, using radiofrequency energy. The new 2-F electrode catheter was used in three patients. The first patient, weighing 2.1 kg, with pulmonary atresia and an intact ventricular septum, underwent transcatheter valvotomy at the age of 18 days. Due to massive left ventricular volume overload, the patient required surgical ligation of the ductus arteriosus, but she was discharged uneventfully after that. The second patient, weighing 2.2 kg, had Ebstein's anomaly with pulmonary atresia and an intact ventricular septum. She underwent transcatheter valvotomy at the age of 30 days. Although she was weaned from prostaglandin E1 infusion, she died suddenly (presumed septicemic). A postmortem examination showed a split pulmonary valve. The third patient, weighing 2.3 kg, with pulmonary atresia and an intact ventricular septum, underwent transcatheter valvotomy at the age of 17 days. Prostaglandin E1 infusion was discontinued on the 3rd day after the transcatheter valvotomy and she was discharged uneventfully.

Angiography↗

Hemodynamic effects of human atrial natriuretic peptide after modified Fontan procedure.

BACKGROUND: Reduction of pulmonary vascular resistance and maintenance of urine output are important after the modified Fontan procedure. Atrial natriuretic peptide (ANP) has the effects of a vasodilator (including the pulmonary arteries) and a physiologic diuretic, and newly synthesized human ANP is available. We measured plasma ANP levels before and after the Fontan procedure and examined the effects of human ANP on hemodynamic parameters after the Fontan procedure. METHODS: Eight patients, aged 2 to 15 years, underwent the Fontan procedure (atriopulmonary connection). Blood samples were taken before and 3 hours after operation, and plasma ANP levels were measured by radioimmunoassay. The correlation between central venous pressure and ANP was examined. Human ANP was infused intravenously at a dosage of 0.1 microg x kg(-1) x min(-1) for 1 hour after the Fontan procedure under controlled ventilation and another blood sample was obtained. Urine volume and central venous pressure were measured, and pulmonary vascular resistance and the cardiac index were calculated by the thermodilution catheter method before and after human ANP infusion. One hour after human ANP infusion was discontinued, the evaluation was repeated. No other diuretics were given and the infusion rates of catecholamine were kept constant during these measurements. RESULTS: Plasma ANP levels before and after the Fontan procedure were 29.1 and 54.9 pg/mL, respectively, and a positive correlation was obtained between central venous pressure and plasma ANP levels (r = 0.661, p < 0.05). Human ANP infusion significantly decreased central venous pressure and pulmonary vascular resistance, and increased urine volume and the cardiac index, whereas the plasma ANP level was elevated to 617.5 pg/mL. Systemic blood pressure did not change significantly. CONCLUSIONS: Atrial natriuretic peptide is secreted in response to elevated central venous pressure after the Fontan procedure, but its concentration might not be sufficient. Human ANP can be a therapeutic choice after the Fontan procedure as a physiologic diuretic and a pulmonary vasodilator.

Adolescent↗

Ameliorative effect of SA4503, a novel cognitive enhancer, on the basal forebrain lesion-induced impairment of the spatial learning performance in rats.

We investigated the effect of successive administrations of SA4503 (1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride), a novel cognitive enhancer with high affinity and selectivity for the sigma1 receptor subtype, on the cortical cholinergic dysfunction-induced impairment of the spatial learning performance in the Morris water maze (MWM) task in rats. The impairment of the spatial learning performance was produced by the ibotenic acid-induced lesion of the basal forebrain (BF) area in rats. Escape latencies to find the platform during the training trials of the MWM task were significantly prolonged in the BF-lesioned rats compared with the sham-operated rats. Daily treatment with SA4503 (0.1-0.5 mg/kg, P.O./day) for 13 days ameliorated this learning deficit. In the probe trial, BF-lesioned rats reduced the number of times each rat crossed the former platform location during the training trials (goal area) in comparison with sham-operated rats. Successive administrations of SA4503 (0.25 mg/kg, P.O./day) also significantly increased the BF lesion-induced reduction of the number of times each rat crossed the goal area. These results suggest that the successive administrations of SA4503 attenuate the impairment of the spatial learning performance in rats with cortical cholinergic dysfunction, and that SA4503 is useful as a therapeutic drug for Alzheimer's disease.

Animals↗

Activation of sigma1 receptor subtype leads to neuroprotection in the rat primary neuronal cultures.

The mechanisms of sigma (sigma) receptor ligands-induced neuroprotective effects are controversial because both sigma receptors and phencyclidine (PCP) binding sites of the N-methyl-D-aspartate (NMDA) receptor channel complex have been reported to contribute to these neuroprotective effects. Thus, to clarify the role of sigma receptor in the neuroprotective effects, we examined the effects of 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride (SA4503), a novel sigma1 receptor agonist with negligible affinity for the NMDA/PCP receptor channel complex, on the hypoxia/hypoglycemia- and exogenously applied NMDA-induced neurotoxicity in the rat primary neuronal cultures. A selective sigma1 receptor agonist, SA4503, significantly suppressed the hypoxia/hypoglycemia-induced neurotoxicity in the cultures, whereas this agonist failed to inhibit the NMDA-induced neurotoxicity. Similarly, (+)-pentazocine ((+)-PTZ), a prototype sigma1 receptor agonist, inhibited the hypoxia/hypoglycemia-induced neurotoxicity, whilst it did not affect the NMDA-induced toxicity in the cultures. These neuroprotective effects of SA4503 and (+)-PTZ were partially blocked by N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine monohydrochloride (NE-100), a putative sigma1 receptor antagonist. These results suggest that the sigma1 receptor subtype plays an important role in the sigma receptor ligands-induced neuroprotective effects via the regulation of excitatory amino acids (EAAs) release from the presynaptic sites.

Animals↗

Central acinic cell carcinoma of the mandible. Report of a case.

Central acinic cell carcinoma is extremely rare; only six cases have been reported in the literature. An unusual case of central acinic cell carcinoma of the mandible in an 84-year-old Japanese woman is presented. This is thought to be the seventh case of central acinic cell carcinoma described in the English literature.

Aged↗

Fetal ventricular tachycardia in long QT syndrome.

We report a case of a fetus presenting intermittent ventricular tachycardia during mid-gestation, whose mother had long QT syndrome. The arrhythmia disappeared spontaneously, and the electrocardiogram of the baby after birth showed prolonged QTc. As far as we are aware, this is the first case in which ventricular tachycardia was documented during fetal life in a baby with long QT syndrome.

Adult↗

Cloning and characterization of three isoforms of OS-9 cDNA and expression of the OS-9 gene in various human tumor cell lines.

OS-9 gene is frequently coamplified with CDK4 gene in human sarcomas. We isolated and characterized three isoforms of OS-9 cDNA found in a myeloid leukemia HL-60 cDNA library. Isoform 1 consisted of 2,700 bp, from which a 667 amino acid sequence was deduced and found to be identical with that of OS-9 cDNA from osteosarcoma cells [Su et al. (1996) Mol. Carcinogen. 15, 270-275]. Isoform 2 cDNA lacked a 165 nucleotide sequence in the coding region. Isoform 3 cDNA had an additional 45 bp deletion in the coding region. Isoforms 2 and 3 encode 612 and 597 amino acid polypeptides, respectively. Comparison of their cDNA sequences with the genomic structure indicated that three isoforms are splice variants. Reverse transcription-polymerase chain reaction analysis showed predominant expression of isoform 2 mRNA in myeloid leukemia HL-60 cells, osteosarcoma OsA-CL cells and rhabdomyosarcoma Rh30 cells. Northern blotting revealed similar levels of expression of OS-9 gene in various tumor cell lines of sarcoma cells, carcinoma cells and myeloid leukemia cells, but 3-4 times higher expression in OsA-CL cells and Rh30 cells containing a homogeneously staining region of 12q13-15. OS-9 expression decreased in differentiation-induced HL-60 cells. Possible involvement of the OS-9 gene in cell growth is discussed.

Alternative Splicing↗

[Estimation of probiotics by infection model of infant rabbit with enterohemorrhagic Escherichia coli O157:H7].

We examined the preventative effect against enterohemorrhagic Escherichia coli O157:H7 (EHEC) infection in rabbits on administration of probiotics contained in Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus. The probiotics were administered to 5 days old Japanese white rabbits throughout the experiment. Inoculation of 10(6) colony forming units (CFUs) of EHEC per rabbit was tried 8 days after birth. Three days after EHEC inoculation, in the control group (not administered probiotics), diarrhea was observed in approximately 80% of the rabbits, on the other hand, in the group administered probiotics, rabbits showed diarrhea in 15%. In necropsy, the number of EHEC in the contents of the cecum and the number of attaching and effacing (AE) lesions were fewer in the probiotics group than in the control group. These results suggest that infant rabbits are useful as a colitis model for EHEC, and the probiotics are effective for the prevention of the growth of EHEC in the intestine and for diarrhea.

Animals↗

Suppressive activity of the chloroform extract of Tripterygium wilfordii Hook f on effector T cell activation during Hymenolepis nana infection in mice.

The chloroform extract of Tripterygium wilfordii Hook f (TWH extract) administered into mice daily at doses of 80.0 to 200.0 micrograms/kg (but not 40.0 micrograms/kg) caused suppression of protective immunity to Hymenolepis nana when the extract was injected subcutaneously during the induction phase of protective immunity. Daily administration of 200.0 micrograms/kg TWH extract, during the course of larval development from challenge, also suppressed protective immunity. Inhibition of protective immunity was only observed in mice that received TWH extract for 6 days at a daily dose of 200.0 micrograms/kg and were challenged 24 h after the final injection. TWH extract did not inhibit formation of effector cells that mediate delayed type hypersensitivity (DTH) to H. nana egg antigen when the extract was administered subcutaneously at a dose of 200.0 micrograms/kg/day for 5 days before cell preparation. However, TWH extract did inhibit DTH effector cell activation when cells prepared from infected, PBS-injected mice were transferred into 200.0 micrograms/kg TWH extract-treated recipient mice. These results strongly indicate that TWH extract cannot inhibit the generation of effector cells but will suppress their function in vivo.

Animals↗

Fully-Automated Spot Recognition and Matching Algorithms for 2-D Gel Electrophoretogram of Genomic DNA.

We have developed the fully-automated algorithms for processing 2-D gel electrophoretograms based on RLGS (restriction landmark genomic scanning) method; one for fully-automated spot recognition from RLGS electrophoretogram and another for fully-automated pairwise matching of the spots found on such 2-D electrophoretograms. Without any human interaction, several thousands of spots on a 2-D electrophoretogram, including hidden spots found at the shoulder of large spots, can be identified correctly by applying our spot recognition algorithm, except for only a few true-negative and false-positive spots. Once the locations and intensities of the landmark spots are correctly recognized automatically, our pairwise spot matching algorithm reliably and rapidly identifies equivalent pairs of spots found on the nonlinearly distorted RLGS electrophoretograms in the fully-automatic way, i.e., the boring and annoying spot landmarking process is unnecessary. At the beginning of the spot matching process, most suitable pair of corresponding spots is searched automatically, then the other equivalent pairs of spots are identified. With our powerful image processing algorithms, it is possible to detect DNA molecular changes such as deletions, additions, amplifications or DNA methylations occurring at or near to the restriction enzyme cleavage sites by means of comparing large amount of RLGS electrophoretograms, without any visual inspection and human interaction.

Journal Article↗

Increased frequencies of interleukin-2- and interferon-gamma-producing T cells in patients with active Behçet's disease.

PURPOSE: To elucidate the profile of cytokine-producing T cells in patients with active or inactive Behçet's disease (BD), the frequencies of type 1 (Interleukin- [IL] 2, interferon-gamma [IFN-gamma]) and type 2 (IL-4) cytokine-producing CD4+ and CD8+ cells in peripheral blood were investigated, and the effect of immunosuppressive drugs on the profile of cytokine-producing cells was evaluated. METHODS: Fifty-two patients with BD (32 with active and 20 with inactive BD) and 33 healthy control subjects were the subjects in this study. Patients were or were not treated with immunosuppressive drugs. Peripheral blood mononuclear cells were fixed, permeabilized, and stained for intracellular cytokines in combination with cell surface markers CD4 and CD8 for flow cytometric analysis. RESULTS: In nontreated patients with BD, the frequencies of IL-2- and IFN-gamma-producing CD4 and CD8+ cells in active patients were significantly higher than those in inactive patients. Conversely, the frequencies of IL-4 producing CD4+ and CD8+ cells in nontreated patients with active BD were comparable with those in patients with inactive disease and in control subjects. Patients with inactive BD who were treated with immunosuppressive drugs showed significantly lower frequencies of IL-2- and IFN-gamma-producing CD4+ and CD8+ cells than did treated patients with active BD. CONCLUSIONS: The frequencies of type 1 cytokine-producing CD4+ and CD8+ cells increased in patients with active BD. Effective immunosuppressive treatments decreased the population of type 1 cytokine-producing CD4+ and CD8+ cells. These results suggest that type 1 cytokine-producing cells play an important role in the immunopathogenesis of the inflammation in BD.

Adolescent↗

[Catheter intervention for adult congenital heart diseases].

The efficacy of catheter intervention for adult congenital heart diseases was evaluated in 27 patients aged 20 to 52 years (mean age at catheterization 25 +/- 7 years) from 1986 to 1996. Four patients had pulmonary valve stenosis, four had aortic valve stenosis, three had coarctation of the aorta, 10 had pulmonary artery stenosis, four had cyanotic heart diseases and aorto-pulmonary collateral arteries, one had patent ductus arteriosus, and one had cyanotic heart disease and stenotic Blalock-Taussig shunt. Balloon dilation was successful in all patients with pulmonary valve stenosis, and follow-up evaluation (1-8 years) showed no restenosis in any patients. Balloon dilation was successful in all patients with aortic valve stenosis, and follow-up evaluation (0.5-5 years) showed transvalvular pressure gradient < 50 mmHg. Stenosis was relieved successfully in all patients with coarctation of the aorta, and follow-up evaluation showed no restenosis. Balloon dilation was successful in eight of 13 locations (62%) in patients with pulmonary artery stenosis. Coil embolization was successful in all patients with cyanotic heart diseases and aortopulmonary collateral arteries. In a patient with patent ductus arteriosus, two coils were placed in the ductus arteriosus but were retrieved because hemolysis was observed after the embolization. These data indicate that catheter intervention in young adults with congenital heart diseases is as effective as in children.

Adult↗

[Unilateral gustatory disturbance by pontine infarction].

We reported a case of pontine infarction presenting as diminished taste on the contralateral side. A 67-year-old man was hospitalized with a sudden onset of right hypogeusia. No neurological abnormalities were found except diminished taste in the areas innervated by the chorda tympani, greater petrosal and glossopharyngeal nerves on the right side. Brain MRI demonstrated a lesion with low-intensity on T1-weighted images and high-intensity on T2-weighted images in the left suprapontine tegmentum. Cases of pontine disease presenting as contralateral dysgeusia have rarely been reported. In the present case, we considered that infarction occurred superior to the pontine taste are (PTA). It is suggested that the gustatory pathway superior to PTA takes a chiasmal tract ascending in the brainstem.

Cerebral Infarction↗

Cardiac outflow tract septation process in the mouse model of transposition of the great arteries.

It has been reported that all-trans retinoic acid induces transposition of the great arteries (TGA) at 80-90% in ICR mice. The authors revealed that retinoic acid affects the initial formation of the conus cushions leading to a loss of spirality in the cardiac outflow tract. However, the aberrant process of septation has not been precisely defined. In this study, we observed the hearts of live embryos using a video system followed by scanning electron microscopic examination. First, we found that, in the retinoic acid-treated embryos, the proximal outflow tract cushions, in addition to hypoplasia and dysplasia, did not establish the continuity with the distal outflow tract cushions and could not contribute to the outflow septation. Second, the distal outflow tract did not rotate counter-clockwise, retaining the outflow septum anlage in the superoinferior position. Third, a tongue-like mesenchymal tissue had developed on the right anterior rim of the muscular interventricular septum and was incorporated into the interventricular septum. Altogether, these processes contributed to establishing a reversed relationship between the outflow septum anlage and the ventricular septum anlage. On the other hand, right-ward deviation of one or both of the distal outflow tract cushions, relative to the mesenchymal tissue, gave rise to variable degrees of overriding of the pulmonary artery orifice. We conclude that, due to hypoplasia and dysplasia of the proximal outflow tract cushions and lack of distal outflow tract rotation, the outflow septum anlage took an inverted relationship with the ventricular septum anlage. Various types of rightward shift of the outflow tract cushions produced a morphological spectrum of TGA-type cono-truncal anomalies.

Animals↗