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Biomedical subjects

K Matsubara

Publications and source records attributed to K Matsubara.

At least 307 records · Page 17Linked to original sources
PubMed1991

Production and effect of infectious Dane particles in transgenic mice.

We have demonstrated by immunoelectron microscopy that 42-nm particles with double-shelled structures characteristic of Dane particles are present in the serum of transgenic mice, 1.2HB-BS 10, carrying partly duplicated hepatitis B virus (HBV) genome. Furthermore, these particles were shown to infect primary human fetal hepatocytes as demonstrated by the elevation of HBV surface antigen (HBsAg) in the culture medium. HBV DNA is known to be expressed in a liver- and kidney-specific manner in the adult mouse, so we examined the developmental expression of viral antigens. In the liver, viral antigens (HBsAg and HBV e antigen) began to be expressed before birth and the level of expression showed a sharp rise after birth. On the other hand, in the kidney, viral antigens began to be expressed after birth. Serum levels of viral antigens were roughly proportional to the levels of expression in the liver, suggesting that the liver is the main source for viral antigens in the serum. None of these transgenic mice produced anti-HBs or anti-HBV core response or showed biochemical or pathological change up to at least 24 months of age. All these results suggest that infectious viral particles can be produced in transgenic mice, and that expression and replication of HBV DNA are not toxic in vivo.

Aging↗
PubMed1991

Familial juvenile nephronophthisis in two siblings--histological findings at an early stage.

We present two female siblings with familial juvenile nephronophthisis (FJN) which was diagnosed at the early stage of renal failure. Diagnosis was made during the investigation of anemia in case 1 and by a subsequent family survey in case 2. Most patients with FJN are not identified until the terminal stage of renal failure and such cases have rarely been reported in Japan. Case 2 had a reduction in the maximum urinary concentration ability but no azotemia, and among the FJN patients reported in Japan so far she has the least advanced renal disease. Histological examination of the renal biopsy in case 1 showed typical findings of FJN, such as thickening and lamination of the tubular basement membrane (TBM), interstitial fibrosis, and round cell infiltration of the interstitium. In case 2, renal biopsy revealed an irregular marked thickening of the TBM with trivial interstitial changes and a normal glomerular appearance. The histology of these two cases suggests that the TBM may be the primary site affected in FJN.

Child↗
PubMed1991

Chromosomal sites for hepatitis B virus integration in human hepatocellular carcinoma.

The discovery that hepatitis B virus (HBV) integrates into host chromosomes raises the question of whether such viral DNA integration correlates directly with the activation of specific oncogenes or the inactivation of anti-oncogenes. To obtain insight into this problem, we randomly collected HBV integrant samples from different human hepatocellular carcinomas and identified the site of chromosomal integration by using in situ hybridization and/or linkage analysis with the flanking cellular DNAs as probes. Our findings did not specifically identify particular HBV DNA integration sites in chromosomes, although chromosomes 11 and 17 seemed to have more than the average number of integrants.

Alleles↗
PubMed1991

Three envelope proteins of hepatitis B virus: large S, middle S, and major S proteins needed for the formation of Dane particles.

The infectious particles of hepatitis B virus are called Dane particles and consist of viral nucleic acid encapsulated within a core particle that is enveloped by virus-coded surface proteins. The major S protein constitutes a significant fraction of these surface proteins. In addition, there are two other related proteins (large S and middle S), but their role in envelope formation has not yet been elucidated. We modified the translation initiation codon ATG of each of the envelope proteins by site-directed mutagenesis and found that mutant genomes that did not produce one or two of these proteins were unable to form Dane particles. The particles released into the culture medium by such mutants did not carry DNA. Synthesis of virus-coded RNA still occurred normally, and core particles carrying DNA accumulated intracellularly. The DNA in such core particles was mostly in the double-stranded open circular form, in contrast to the normal situation in which the particles contain mostly RNA and its complementary single-stranded DNA or else contain linear DNA that is partially single stranded and otherwise duplex. The role of the large S and middle S proteins in the formation of Dane particles is discussed.

Blotting, Northern↗
PubMed1991

Endogenous retroviral LTR DNA sequences as markers for individual human chromosomes.

The human genome carries multiple copies of sequences related to endogenous retroviral genomes that include long terminal repeat (LTR) sequences. We used the LTR of one such viral genome, called HERV-A, as a probe in Southern analysis to examine the distribution profiles of the hybridizing DNA in the genomes of twelve human x rodent hybrid cell lines carrying one or a few human chromosomes, and in the DNA samples prepared from six sorted, individual chromosomes. The HERV-A sequence was found to be widely distributed among different chromosomes and the Southern patterns for chromosomes 5, the X, and the Y, each obtained in duplicate from independently prepared cell lines or sorted chromosomes, were matched. Chromosome-specific Southern profiles can be used to monitor chromosomes in hybrid cells or to characterize chromosome aberrations, such as deletions.

Actins↗
PubMed1991

Reproducibility of diurnal variation of heart rate.

Heart rate variation has been utilized as a parameter for validating autonomic nerve and sinus node function. However, few reports are available on the reproducibility of such data. In the present study, we studied the reproducibility of the diurnal variation of heart rate in 15 patients, and the effect of age differences on the variation in 30 normal men using a Holter ECG monitoring method. For investigating reproducibility, Holter ECG monitoring was performed twice, the two measurements being separated by a short interval. A moving average method applied on heart rate of every 3h exhibited essentially the same diurnal pattern of heart rate between two records in each patient. Excellent reproducibility of the pattern was also demonstrated by a lag correlation analysis. Variability of heart rate in normal men was independent of age. These results suggest that heart rate variation was essentially constant in each subject, at least within a short period.

Adult↗
PubMed1991

Visualization of the heart and determination of left ventricular mass in rats by echocardiography.

A high-frequency transducer was used to determine the optimal parameters for visualizing the heart in 40 normal Wistar, 15 SHR, and 10 aorta-banded rats. The rats were 5 to 30 weeks old and weighed between 105 and 705 grams. Two-dimensional and M-mode views of the ventricles, atria, valves, and great arteries were obtained by placing the transducer beneath the rats through the left or right parasternal window in either the prone or the right decubitus positions, respectively. Left ventricular (LV) mass was determined on the basis of a spheroid model; these values correlated well with the LV weight for both the Wistar rats (r = 0.94, p less than 0.001) and the rats with cardiac hypertrophy due to pressure load (r = 0.87, p less than 0.001). These results were highly reproducible. This indicates that echocardiography is useful for obtaining quantitative measurements in rats.

Animals↗
PubMed1991

A novel system for large-scale sequencing of cDNA by PCR amplification.

We have developed a method for constructing a library containing the 3' end fragment of cDNA for large-scale sequencing of cDNA clones. The average size of the insert was 270 bp. Cell lysates that carry plasmids having the cDNA insert were subjected to PCR amplification of the cDNA moiety and the products were subjected to sequencing analysis using an autosequencer. With this protocol, sample preparation became a non-limiting step, that allowed us to sequence as many samples as the autosequencer could handle.

Base Sequence↗
PubMed1991

Colorimetric determination of fructosamine in hemolytic samples for the postmortem diagnosis of diabetes mellitus.

An analytical method of fructosamine (glycated serum protein) determination in hemolytic samples from cadavers was investigated for the postmortem diagnosis of diabetes mellitus. Fructosamine level is usually measured by the reduction of nitroblue tetrazolium (NBT) using a spectrophotometer. This assay was significantly disturbed by more than 1 g/l hemoglobin, which strongly reduced NBT by the catalytic action of the sulfhydryl and glycated groups. Glycated and total hemoglobin levels were then determined simultaneously to exclude the interferences. Total protein concentration was analyzed to eliminate dilutional effects by hemolysis. With these modifications, corrected fructosamine levels in samples containing not more than 10 g/l hemoglobin could be estimated. The assay of such hemolytic samples from 32 cadavers indicated higher fructosamine values in diabetic group than in non-diabetic subjects and the postmortem degradation of the levels as previously reported.

Adolescent↗
PubMed1991

[The clinical significance of reverse redistribution of Tl-201 SPECT at rest in the 1st month after the onset of acute myocardial infarction].

The pattern of Thallium-201 reverse redistribution (r-RD) at rest has been reported in some patients with acute myocardial infarction (AMI) in the acute phase. But there is no report of this pattern in the later phase. To investigate the significance of Thallium-201 reverse redistribution in the subacute phase, 37 patients with AMI underwent Thallium-201 SPECT at rest a month after the onset. The patients were classified into three groups visually and 19 of 37 patients (51%) showed the persistent defect pattern (Group PD), and the remaining 18 patients (49%) had the reverse redistribution pattern (Group r-RD). None of them had the redistribution pattern. Coronary reflow was earlier and the incidence of the scintigraphic overlap on Dual SPECT image of 99mTc-PYP/201TlCl in the acute phase was more frequent in Group r-RD than in Group PD. A decrease in thallium defect size of patients with r-RD from the acute phase to one month after the onset represented improvement more significantly than that with PD. Initial %Tl uptake of the infarcted region of Group r-RD was greater than that of Group PD. The degree of stenosis of the infarct-related coronary artery in Group r-RD was less severe than that in Group PD. And corresponding regional wall motion of Group r-RD was less impaired. The Thallium-201 washout in the infarcted region with r-RD was significantly faster than that in the normal region. It is concluded that the r-RD pattern at rest in the 1st month after the onset of AMI may be a sign of viable myocardium.

Aged↗
PubMed1991

[Apical sequestration in hypertrophic cardiomyopathy: its clinical features and pathophysiology].

The clinical and pathophysiological significance of apical sequestration, in which an apical cavity was sequestered from the remainder of the left ventricle by cavity obliteration was investigated in patients with hypertrophic cardiomyopathy (HCM). Among 196 consecutive patients, 24 with apical sequestration and 70 control subjects proven to have no sequestration with left ventriculography were selected for this study using echocardiography combined with Doppler color flow imaging. Various cardiac disorders occurred significantly more frequently in patients with apical sequestration than in the 70 controls: NYHA > or = II, 83% vs 51%; thromboembolism, 17% vs 3%; ventricular tachycardia, 47% vs 11%; and apical asynergy, 75% vs 4%. Continuous Doppler ultrasound revealed that all 24 patients with sequestration had a high systolic blood flow velocity across the obliterated cavity (2.7 +/- 0.9 m/s). During isovolumic relaxation or early diastolic filling or both, 21 of them had paradoxical jet flow directed toward the basal cavity away from the apex, with the peak flow velocity ranging from 1.0 m/s to 3.5 m/s (mean 1.9 +/- 0.7). The maximal diastolic pressure gradient across the obliterated cavity ranged between 4 mmHg and 49 mmHg using the simple Bernoulli's equation, which suggested a significantly higher pressure in the sequestered apical chamber during early diastole. Patients with sequestration were classified into 2 groups; 17 with (group A) and 7 without (group B) apical hypertrophy. The time interval from the closing of the aortic valve to the onset of filling into the sequestered cavity was longer in group A than in group B (401 +/- 191 vs 131 +/- 145 ms, p < 0.01) as assessed by the pulsed Doppler technique. Angiographic asynergy of the apex was more frequent in group A than in group B (100 vs 29%, p < 0.01). In group B, the midventricular cavity was incompletely obliterated throughout the cardiac cycle; whereas, in group A, it was obliterated completely in systole and partially in diastole. Apical sequestration is not uncommon in HCM; it is accompanied by abnormal segmental wall motion, which may be related to ventricular arrhythmias and thromboembolism. Prolonged cavity obliteration with a higher systolic apical pressure and a persistent diastolic intraventricular gradient may play a pathogenic role in apical aneurysmal formation in the absence of fixed coronary artery disease, particularly in patients with apical hypertrophy.

Adolescent↗
PubMed1991

Abnormalities of plasma lipoproteins in a new genetically obese rat with non-insulin-dependent diabetes mellitus (Wistar fatty rat).

We investigated plasma lipoprotein profiles and the activities of tissue cholesterol regulating enzymes in Wistar fatty rats, an animal model for non-insulin-dependent diabetes mellitus (NIDDM). Wistar fatty rats were made by transfer of the fa gene to the Wistar Kyoto rats by backcross-breeding. Wistar fatty and control non-diabetic littermates were given a laboratory chow or an atherogenic diet containing 1 percent (weight percent) cholesterol, 0.5 percent cholic acid, and 5 percent lard. Under the chow diet, plasma fasting glucose and immunoreactive insulin concentrations in Wistar fatty rats were 1.5- and 6-fold higher than controls, respectively. Plasma cholesterol was significantly increased in Wistar fatty rats compared with controls. Elevated plasma cholesterol levels in Wistar fatties was accounted for by the increases of cholesterol content in the d less than 1.006 g/ml lipoprotein and high-density lipoproteins. Under the atherogenic diet, plasma cholesterol levels in Wistar fatties were further increased by 129 percent compared with controls. The diet-induced increase of cholesterol contents was shown in all lipoprotein classes for Wistar fatty rats. The activities of regulatory enzymes for cholesterol biosynthesis or absorption were measured in Wistar fatty rats. Both hepatic and intestinal 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase activities were significantly higher in Wistar fatty rats than those in controls (P less than 0.05 and P less than 0.01, respectively). ACAT activities in Wistar fatties were significantly increased in the intestine (P less than 0.05) and decreased in the liver in comparison with controls (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

[A case of hypertrophic cardiomyopathy with progressive cavity dilatation--a review of serial 201Tl myocardial imaging].

We reviewed 201Tl images of a 32 year old man with dilated hypertrophic cardiomyopathy (DHCM). At 22 years of age, when he was diagnosed as having nonobstructive hypertrophic cardiomyopathy (HCM)IVST; 20mm, Dd; 44mm, EF; 62%), 201Tl images showed only a small defect in the anteroseptal segment. At 27 years of age, when he had the first cardiac symptom as palpitation on exertion, his perfusion defect of 201Tl became wider. At 32 years age, he was hospitalized because of deterioration of congestive heart failure. Echocardiography revealed left ventricular wall thinning(IVST; 6mm), left ventricular cavity enlargement (Dd; 63mm) with a large mural thrombus and reduced left ventricular ejection fraction (EF; 32%). Thus 201Tl images may provide useful information on the process of DHCM from HCM.

Adult↗
PubMed1991

[The early changes in bone mineral metabolism due to radiation--measurement of bone mineral density in lumbar vertebra by quantitative computed tomography].

Osteosclerosis, osteonecrosis and compression fracture are commonly observed several years after radiation. Since lumbago usually occurs several months after radiation, the possibility that bone mineral metabolism is disturbed during and immediately after radiation cannot be ruled out. However, there have been no reports concerning early changes in bone mineral metabolism due to radiation. The bone mineral density was measured by QCT (Quantitative Computed Tomography) in 30 normal non-radiated cases and 14 radiated cases to investigate the changes in bone mineral metabolism due to radiation. The bone mineral density (QCT-Value: QCT-V) in the 3rd lumbar vertebra (L3) of normal non-radiated subjects decreased linearly with age (Y = 291.114447-3.01473X). The QCT-V of the 5th lumbar vertebra (L5) of normal cases also decreased linearly with age (Y = 309.641397-3.03986X), resembling that of L3. The ratio of the QCT-V of L5 to L3 (L5/L3, expressed as a percentage) definitely increased with age (Y = 86.5657441 + 0.58885064X). In radiated cases, the QCT-V of L3 in the non-radiated field did not change appreciably. The QCT-V of L5 in the radiated field was decreased from 20GY and reached 53.08 +/- 17.37% of the pre-radiation value after 50GY. The L5/L3 ratio was also decreased from 20GY and reached 55.47 +/- 15.32% of the pre-radiation value after 50GY. It becomes apparent that the QCT-V of the radiated lumbar vertebra is decreased during radiation. It is suggested that bone mineral metabolism may be disturbed in the early phase of radiation.

Bone Density↗