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Biomedical subjects

M Nakazawa

Publications and source records attributed to M Nakazawa.

At least 217 records · Page 12Linked to original sources
PubMed1995

X linked ocular albinism in Japanese patients.

Thirteen affected Japanese male patients and 13 female carriers with X linked ocular albinism from seven families were examined to assess their clinical findings and to compare them with those of white and black patients. Affected Japanese patients had poor visual acuity, horizontal nystagmus, macular hypoplasia, and loss of stereopsis. Some affected patients had non-albinotic fundus with moderate pigmentation. The amount of pigment in the fundus varied among affected patients and appeared to be between that of the white and black patients. All affected patients had brown irides that show no translucency. Interestingly, two affected patients had megalocornea and a third affected patient had posterior embryotoxon. All female carriers exhibited good visual acuity, normal eye position, stereopsis, brown irides without translucency, and the typical mosaic pattern in the fundus. The pigmented iris and fundus made the correct diagnosis of these affected patients difficult. Nine affected patients (70%) had been diagnosed initially as having congenital nystagmus, with or without macular hypoplasia, until they were reviewed for this study.

Adolescent↗
PubMed1995

Autosomal dominant retinitis pigmentosa locus on chromosome 19q in a Japanese family.

A large four generation Japanese family was studied, in which autosomal dominant retinitis pigmentosa (ADRP) of very variable expression was segregating. Positive lod scores with maxima between 1.557-5.118 at theta = 0.00, strongly suggestive of linkage, were obtained for KLK, D19S180, D19S418, and D19S254 on chromosome 19q. Recently, an ADRP locus has been mapped to the same region in a British family, in which, again, several members subjectively had no clinical evidence of the disease although they had both an affected parent and an affected child.

Adolescent↗
PubMed1995

Hemodynamics and ventricular function in the day-12 rat embryo: basic characteristics and the responses to cardiovascular drugs.

We investigated the basic characteristics of the rat embryonic circulation and also looked at the hemodynamic effects of alpha- and beta-agonists, digitalis, and atrial natriuretic peptide, using a modified organ culture system in which the embryo was placed in oxygenated Hanks' balanced salt solution, blood pressure was measured by a servo-null micropressure system, and blood flow pattern was obtained by a 20-MHz pulsed Doppler velocity meter. The peak pressure was 0.5 +/- 0.04 (SEM) mm Hg at the atrium (n = 6), 2.3 +/- 0.10 mm Hg at the ventricle (n = 15), 1.6 +/- 0.03 mm Hg at the truncus (n = 7), and 1.0 +/- 0.05 mm Hg at the umbilical artery (n = 21). There was a pressure drop from the ventricle to the truncus and then a smaller pressure decrease to the umbilical artery. The atrial a-wave was 20% of ventricular pressure and ventricular inflow blood flow pattern showed very low early-to-late filling ratio, indicating that the ventricle was stiff. These findings were essentially the same as in the chick embryo. We recorded the ventricular image by using a high-speed video system with a frame rate of 200/s, and the ventricular pressure-area loop showed a triangular shape with short isovolumetric phases, which was different from that of the chick embryo at a similar stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Long-term results after surgical repair of total anomalous pulmonary venous connection--hemodynamic evaluation of pulmonary venous obstruction with isoproterenol infusion.

To evaluate late pulmonary venous obstruction following surgical repair in patients with total anomalous pulmonary venous connection, which may be disclosed at high cardiac output but not at rest, a hemodynamic study was performed using isoproterenol infusion. The study included 7 patients in NYHA class I, aged from 5 to 12 years (mean 6 years), who had undergone surgical correction in their early infancy (mean 79 days). After a routine catheterization protocol, isoproterenol was infused at a rate of 0.01 microgram/kg per min. On average, cardiac index increased from 4.8 to 8.1 L/min per m2. The pulmonary arterial and wedge pressures following isoproterenol infusion remained normal in all patients, including 1 case with mild pulmonary hypertension. These results suggest that most, if not all, patients with total anomalous pulmonary venous connection repaired in early infancy do not have any hemodynamic impairment if they show no pulmonary venous obstruction within the first 12 months following surgical correction.

Child↗
PubMed1995

Natural infection with attaching and effacing Escherichia coli and adenovirus in the intestine of a pigeon with diarrhea.

Attaching and effacing Escherichia coli (AEEC) and adenovirus infections in a 6-month old pigeon were found by retrospective histologic examinations. Histologically, numerous gram-negative bacilli covered the surface of the enterocytes of the ileum. Brush borders were not sharply defined on the apical enterocytes at the sites of bacterial attachment. Scanning electron microscope showed that much of the mucosal surface was heavily colonized by bacilli and that the microvilli were lost. Many intranuclear inclusions were seen in enterocytes from the duodenum to the cecum. On transmission electron microscopy, adenovirus-like particles were observed in the nuclei of enterocytes.

Adenoviridae↗
PubMed1995

The mechanism of lactitol (NS-4) in inducing adrenomedullary proliferative lesion in rats.

We used 13-week repeated oral administration of lactitol as part of a study to clarify the mechanism by which lactitol induces the proliferation of adrenomedullary chromaffin cells. There was a marked increase in urinary calcium (Ca) excretion even though the lactitol administration had no effect on the blood Ca level. A tendency for an increase in adrenal venous blood epinephrine (EPI) and norepinephrine (NE) concentrations was seen. Organ weight measurement of adrenal glands revealed a tendency for an increase in absolute weight and a significant increase in relative weight. Morphometric analysis of adrenomedullary chromaffin cells showed a tendency for an increased total cell volume and a decreased numerical density; but, there was no conspicuous change in the total cell number. Determinations of the anti-bromodeoxyuridine (BrdU) and antiproliferative cell nuclear antigen (PCNA) antibody-positive cell counts showed a tendency for an increased proliferation rate for adrenomedullary chromaffin cells. Electron microscopy showed a slight increase in the number of Golgi apparatuses in these cells. Because the marked increase in urinary Ca excretion was concomitant with morphological changes that suggested the hyperfunction of chromaffin cells in the adrenal medulla and a tendency for an increased cell proliferation rate, we assume that persistent hyperfunction of the adrenomedullary chromaffin cells, which was mediated by enhanced Ca absorption from the intestinal tract, may have induced proliferative lesion.

Adrenal Medulla↗
PubMed1995

[Single dose toxicity studies of metabolite, degradation product and impurity of montirelin hydrate (NS-3) in mice].

Montirelin hydrate (NS-3) is a new drug for the treatment of disturbance of consciousness. The single dose toxicity studies of its degradation product and impurity (CNK-603) and its metabolite (CNK-6004) were conducted in Slc: ddY mice. The compounds were administered intravenously to male and female mice. Deaths occurred in both sexes of mice receiving more than 125 mg/kg of CNK-603. There were no treatment-related effects on survival in both sexes of mice receiving doses up to 2,000 mg/kg of CNK-6004. Approximate lethal dose of CNK-603 was 125 mg/kg and lethal dose of CNK-6004 was more than 2,000 mg/kg. Decrease in locomotor activity was observed in mice receiving the two compounds. Tremor, prone position and dyspnea were seen in mice receiving CNK-603. The body weight showed no changes attributable to the dosing of the two compounds in mice. In autopsies, congestion and hemorrhage in the lung were observed in dead mice given CNK-603. There were no remarkable changes in mice given CNK-6004. These results show that the lethal dose of CNK-603 is over 4 times lower than that of montirelin hydrate, and that CNK-6004 is less toxic than montirelin hydrate.

Animals↗
PubMed1995

Alteration of glutamine concentration in the vitreous humor in patients with proliferative vitreoretinopathy.

Using sensitive high performance liquid chromatography (HPLC), we measured free amino acid concentrations in the undiluted vitreous samples of patients who underwent pars plana vitrectomy for treatment of idiopathic preretinal macular fibrosis (PMF, n = 8), proliferative diabetic retinopathy (PDR, n = 12), or proliferative vitreoretinopathy (PVR, n = 15) to investigate the effect of vitreoretinal diseases on the concentrations of free amino acids in human vitreous. The most abundant amino acid was glutamine in all of three groups. Other major amino acids commonly found in the human vitreous samples were serine, alanine, arginine, valine, and lysine. Patients with PDR and PVR showed significantly lower concentrations of glutamine in vitreous (PDR: 655 +/- 230 nmoles/ml, PVR: 683 +/- 302 nmoles/ml) than those with PMF (PMF: 975 +/- 247 nmoles/ml; significance level, PDR: p < 0.01, PVR: p < 0.05). In addition, patients with grade D PVR showed significantly lower concentration of glutamine (357 +/- 117 nmoles/ml) than those with grade C PVR (802 +/- 256 nmoles/ml, p < 0.005), or PMF (p < 0.005). These results suggest two possible mechanisms for the alteration of intravitreal glutamine in the pathologic conditions. The first possibility is a reduced amount of supply of glutamine that is normally transported or released from surrounding tissues into vitreous humor. The second possibility is an increased amount of uptake and utilization of glutamine by cells within vitreous and pathologic tissues.

Adolescent↗
PubMed1995

[Adherence to HEp-2 cells of enterotoxemic Escherichia coli O-group 139 from pigs with edema disease].

One hundred and one strains of enterotoxemic Escherichia coli (ETEEC) O-group 139 isolated from swine with edema disease were investigated for their adherence to HEp-2 cells in the presence of D-mannose. All strains adhered in large numbers to the cells (21 to 60 bacteria/cell). No correlation was found between the presence of F107 fimbria on the organisms and the adherence to the cells. Adhesion-inhibition tests showed that anti-K12 serum inhibited the adhesion ETEEC O-group 139 (an inhibition rate of 63 to 65%), but anti-F107 or anti-O139 sera did not. These results indicate that the capsular K12 antigen may be one of the pathogenic factors of ETEEC O-group 139.

Animals↗
PubMed1995

Specific antibody patterns of Wistar rats inoculated with third stage larvae of Anisakis simplex.

Levels of excretory-secretory (ES)-specific antibody were measured in Wistar rats inoculated with 1, 5, or 20 third stage larvae (L3) of Anisakis simplex. Primary inoculation induced ES-specific IgM and IgG titers, paralleling inoculum size. Secondary inoculations resulted in an IgM and IgG titer augmentation in 1 or 5 larvae-inoculated animals to levels comparable to those of animals inoculated with 20 larvae, but titers in high inoculum animals did not increase upon secondary inoculation. Primary inoculation induced low ES-specific IgE antibody titers. However, secondary inoculation produced a different pattern than with IgM or IgG titers. Instead of titers equivalent to animals receiving more larvae, rats receiving 1 larva developed higher IgE titers than rats receiving larger inoculums. IgE titers of single larvae-inoculated rats peaked at 3-5 days after secondary inoculation but disappeared by day 14. The time course of IgE production is therefore consistent with duration of the infection. As the natural infection typically involves few larvae, monitoring ES-specific IgE may be a useful diagnostic tool for human intestinal anisakiasis.

Animals↗
PubMed1995

[Minimally differentiated hypoplastic leukemia].

Sixty-seven years-old female, who was an atomic bomb survivor in Hiroshima, was pointed out as having leukopenia and anemia in 1991. She was referred to Tsukuba University Hospital in June 1992. Her peripheral blood count showed pancytopenia- 2,600/microliters WBC, 10.5 g/dl hemoglobin, and 80,000/microliters platelets- at that time. BM biopsy revealed hypoplastic marrow and increased peroxidase-negative blasts (32.8%). Surface marker analysis of the blasts showed a feature of CD2+ CD33+ CD34+ CD13+ CD3-. Electronmicroscopically, myeloperoxidase was positive. She was diagnosed as having hypoplastic leukemia of which the blasts had a feature of AML-M0 by FAB-group. After 6 months' silent period, her pancytopenia became profound. We successfully reduced the blasts by BAM therapy. However, she died of bacterial pneumonia during the myelosuppressive state. This is a case of minimally differentiated hypoplastic AML.

Aged↗
PubMed1995

[Evaluation of partial volume effect in quantitative measurement of regional cerebral blood flow in single photon emission computed tomography--effects of limited spatial resolution and first-pass extraction fraction].

Two numerical brain phantoms were generated in order to investigate errors which might be included in the quantitative measurement of regional CBF with use of single photon emission computed tomography (SPECT). The first phantom simulated the normal brain, and effects of the limited spatial resolution of the SPECT scanner were evaluated for 4 tracer kinetic models of the conventional microsphere model, the intra-carotid bolus injection technique of 133Xe, 133Xe Kanno-Lassen method, and the IMP-autoradiography (IMP-ARG) method. The second phantom simulated the diseased brain with middle-carotid artery (MCA) occlusion, and effects of the limited first-pass extraction fraction were investigated for the microsphere model with various permeability-surface area products. The limited spatial resolution caused systematic underestimation of the radioactivity concentration in the gray matter regions, and systematic overestimation in the low CBF regions. These errors in the original radioactivity distribution were found to cause further systematic errors in the calculated regional CBF images. It was also found that these errors were highly dependent on the tracer kinetic model employed, e.g., regional CBF values were overestimated in the clearance and the Kanno-Lassen methods compared with the conventional microsphere method, whereas values were underestimated in the IMP-ARG method. It was also shown in this study that the limited first-pass extraction fraction caused significant underestimation in the calculated rCBF values. In addition, regional contrast can be reduced when using a tracer with small PS product.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1995

[Quantitation of regional cerebral blood flow using 123I-IMP from a single SPECT scan and a single blood sampling--analysis on statistical error source and optimal scan time].

Recently, a method has been proposed to measure quantitative regional cerebral blood flow (rCBF) in man using N-isopropyl-p-[123I]-iodoamphetamine (IMP) and single photon emission tomography (SPECT). In this method (IMP-ARG method), a functional map of rCBF was calculated from a single SPECT scan data set, in which effects of the clearance of IMP from the brain was taken into account by employing the 2 compartment model. To avoid the procedures of frequent and/or continuous sampling of the arterial blood that was required in determination of the input function, use of a standard input function and calibrating it by one blood sampling were validated. The present study was intended to investigate the sensitivity to various sources of errors in the IMP-ARG method such as (1) effects of individual difference of the arterial input function, (2) effects of ambiguity of the regional distribution volume (Vd) of IMP, and (3) effects of inaccuracy of the SPECT measurement. It was shown in the present simulation study that errors in the calculated rCBF values were dependent on the SPECT mid-scan time (MST), and that the minimum error corresponded to the MST of approximately 30 min after the IMP infusion. With this optimal MST, errors in rCBF due to the individual difference of the input function was approximately 10%, and the errors due to the ambiguity of the Vd were approximately 8%. The total accuracy of the calculated rCBF in the IMP-ARG method was, therefore, estimated as approximately 13%. Although a relatively large error was expected at a high rCBF area, this study strongly suggested the IMP-ARG method being useful and accurate for providing the quantitative rCBF map for a clinical use.

Amphetamines↗
PubMed1994

rbcL gene sequences provide evidence for the evolutionary lineages of leptosporangiate ferns.

Pteriodophytes have a longer evolutionary history than any other vascular land plant and, therefore, have endured greater loss of phylogenetically informative information. This factor has resulted in substantial disagreements in evaluating characters and, thus, controversy in establishing a stable classification. To compare competing classifications, we obtained DNA sequences of a chloroplast gene. The sequence of 1206 nt of the large subunit of the ribulose-bisphosphate carboxylase gene (rbcL) was determined from 58 species, representing almost all families of leptosporangiate ferns. Phlogenetic trees were inferred by the neighbor-joining and the parsimony methods. The two methods produced almost identical phylogenetic trees that provided insights concerning major general evolutionary trends in the leptosporangiate ferns. Interesting findings were as follows: (i) two morphologically distinct heterosporous water ferns, Marsilea and Salvinia, are sister genera; (ii) the tree ferns (Cyatheaceae, Dicksoniaceae, and Metaxyaceae) are monophyletic; and (iii) polypodioids are distantly related to the gleichenioids in spite of the similarity of their exindusiate soral morphology and are close to the higher indusiate ferns. In addition, the affinities of several "problematic genera" were assessed.

Base Sequence↗
PubMed1994

[Accelerated hyperfractionation in the treatment of malignant glioma].

A retrospective evaluation was performed to determine whether accelerated hyperfractionation (AHF) improves the survival rate of patients with malignant gliomas. One hundred and seven patients with malignant gliomas, including glioblastoma multiforme, who had received radical radiotherapy were evaluated. Of the patients, 36 were treated by conventional fractionation (CF), and 71 by AHF. The treatment results of the two regimens were compared with regard to survival rate after therapy. Treatment by AHF was conducted at 10-15 F/W (1.5 Gy/F); the mean total dose was 61 Gy over an average of 27 days. Treatment by CF was conducted at 5 F/week (1.8-2 Gy/F); the mean total dose was 59 Gy over 51 days. Multivariate analysis using Cox's proportional hazard model revealed that AHF significantly increased survival rate. Besides pointing to the selection of the AHF method as a treatment regimen, multivariate analysis showed the following factors to be indicators of favorable prognosis: a histopathological diagnosis other than glioblastoma multiforme, age below 40 years, and supratentorial location of the tumor.

Adolescent↗
PubMed1994

Rp-8-Br-guanosine-3',5'-cyclic monophosphorothioate inhibits relaxation elicited by nitroglycerin in rabbit aorta.

To ascertain whether the activation of cyclic GMP-dependent protein kinase is involved in the relaxant effects of nitroglycerin, the effects of Rp-8-Br-guanosine-3',5'-cyclic monophosphorothioate (Rp-8-Br-cGMPS), an inhibitor of activation of G-kinase by cyclic GMP, were studied. In the isolated rabbit aorta contracted by phenylephrine, Rp-8-Br-cGMPS (30 microM) competitively inhibited the relaxation elicited by 8-Br-cGMP, but not that elicited by 8-Br-cyclic AMP, indicating that Rp-8-Br-cGMPS is a specific inhibitor of activation of cyclic GMP-dependent protein kinase by cyclic GMP. The relaxation elicited by nitroglycerin was inhibited by Rp-8-Br-cGMPS.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

A conformational change associated with the phototransformation of Pisum phytochrome A as probed by fluorescence quenching.

Dynamic quenching of the two lifetime component tryptophan fluorescence of Pisum phytochrome has revealed differential accessibility of certain residues. Both acrylamide and Tl+ ions showed preferential exposure of some tryptophans in Pfr-phytochrome. Greater kq's for Pfr are, however, in contrast with values for Avena phytochrome in which Pr-->Pfr conversion impedes Tl+ access. The Pr short lifetime component was more accessible to Cs+; however, the long component accessibility was approximately 2-fold higher in Pfr. 2-Hydroxy-5-nitrobenzyl bromide (HNB-Br) modification of native Pisum phytochrome was used to reduce the total number of fluorescent tryptophans. The absence of the fluorescence contributions of the three residues which reacted with HNB-Br in both photoisomers increased the Tl+ Ksv's for Pr and Pfr. The two additional HNB-Br modifications specific for Pfr resulted in a reversal of the Stern-Volmer plots relative to the unmodified protein. The regions around four of the 10 tryptophans may represent conformationally photoresponsive areas in Pisum phytochrome A. Furthermore, topographic changes associated with the phytochrome phototransformation are not confined to the 58-kDa chromphore domain, and they involve most if not all of the region from Trp-365 to Trp-787. We also provide evidence that the protein conformation in this region is not completely conserved between Pisum and Avena phytochromes.

2-Hydroxy-5-nitrobenzyl Bromide↗