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Biomedical subjects

K Moriyama

Publications and source records attributed to K Moriyama.

At least 127 records · Page 7Linked to original sources
PubMed1994

Mutations in the transcriptional regulatory region of the precore and core/pregenome of a hepatitis B virus with defective HBeAg production.

Termination mutations in the precore open reading frame of hepatitis B virus (HBV) variants with defective hepatitis B e antigen (HBeAg) production have been demonstrated in both infected patients who have seroconverted to anti-HBe and those with fulminant hepatitis B. A donated plasma sample was found to be positive for the hepatitis B surface antigen, but negative for both HBeAg and anti-HBe. The HBV DNA titer in the plasma was estimated to be 32 pg/ml, and circulating virus-like particles were observed by electron microscopy. The entire nucleotide sequence of the virus was determined and at least 7 nucleotides were found to be unique when compared with previously reported sequences. These nucleotides created no termination codon in the precore/core, pol, preS/S and HBx open reading frames. The deduced amino acid substitutions were 28 Arg--Gln, 94 His--Tyr, 131 Val--Ile and 132 Phe--Tyr of HBx and 715 Met--Val and 789 Asp--Asn of pol. Furthermore, the precore and core/pregenome promoter contained altered 1764 A, 1766 T and 1768 A. Therefore, mutations in regions other than the precore open reading frame can cause defective HBeAg production.

Adult↗
PubMed1994

[Pre-operative autologous blood collection in neurosurgical patients].

Homologous transfusion has been known to cause viral infections and other complications. Recently, autologous transfusion has been adopted widely as a safer and more effective procedure to prevent these complications. The authors report the experiences of 29 patients who had been operated on after preparation of autologous blood. Furthermore, the authors report a study concerning maximum surgical blood order schedule (MSBOS) of these operations. 212 patients operated on between January, 1991 and June, 1993 were used for this study of MSBOS. Although intraoperative transfusion was performed on 14 of 29 patients, the need for homologous transfusion was avoided in 12 of these 14 patients by the use of autologous blood. The frequency of homologous transfusion was reduced significantly after the introduction of pre-operative autologous blood collection in our clinic. The patients' value of hemoglobin fell after the collection of blood but these levels were not so seriously low as to impede the performance of operations. 212 cases of operated patients were divided according to the operative methods and diagnosis for calculation of MSBOS. The results were as follows; Craniotomy and removal of glioma 5u, meningioma 11u, neurinoma 7u, AVM 5u, transsphenoidal surgery 3u, Moyamoya disease 2u and V-P or S-P shunt 0u. Pre-operative autologous blood collection is easy to achieve for scheduled neurosurgical operations, and autologous transfusion is a beneficial procedure which should be used more widely.

Blood Loss, Surgical↗
PubMed1993

Association of RNA with human papillomavirus E7 protein of type 16 but not type 6b.

Nonfused human papillomavirus (HPV) type 16 and 6b E7 proteins were expressed in E. coli and fractionated by ion exchange and gel filtration chromatography. The E7 protein of type 6b was purified, but that of type 16 was found to be associated with RNA molecules which could not be excluded by repeated chromatography. The type 16 E7 protein in CaSki cells was also associated with RNA molecules of the same size.

Animals↗
PubMed1993

Neutralizing antibodies to human interleukin 6 reverse hypercalcemia associated with a human squamous carcinoma.

Bone resorbing cytokines may be associated with abnormalities in bone cell function and calcium homeostasis in a number of pathological conditions. One of these cytokines is interleukin 6 (IL-6), which is a multifunctional cytokine which has been shown to be associated with increased formation of bone resorbing osteoclasts in vitro. In this report, we demonstrate that neutralizing antibodies to human IL-6 lower the blood calcium in nude mice carrying a human tumor associated with increased IL-6 production. There was no effect on blood calcium in hypercalcemic nude mice carrying tumors not associated with increased IL-6 production and normocalcemic tumor-bearing nude mice. These results suggest that increased production of IL-6 may contribute to disturbances in calcium homeostasis in some malignancies, and suggest that neutralization of IL-6 effects can lower the serum calcium in these tumors.

Animals↗
PubMed1993

Isolation of a yeast essential gene, COF1, that encodes a homologue of mammalian cofilin, a low-M(r) actin-binding and depolymerizing protein.

We have cloned a Saccharomyces cerevisiae gene (COF1) encoding a low-M(r) actin-binding protein of 143 amino acid (aa) residues (yeast cofilin; Cof); its aa sequence is 35% identical to porcine Cof. The yeast recombinant Cof produced in Escherichia coli exhibited in vitro activities on actin filaments similar to those of mammalian and avian Cof. Gene disruption and tetrad analysis showed that gene COF1 is essential for yeast cell growth. Expression of the cDNA of porcine Cof or destrin (Des), the latter a Cof-related protein, complemented the cof1 null allele in yeast cells.

Actin Depolymerizing Factors↗
PubMed1993

Detection of a point mutation in cholesteryl ester transfer protein gene by polymerase chain reaction-mediated site-directed mutagenesis.

We describe a method for the rapid and non-radioactive examination of DNA samples for a mutation of cholesteryl ester transfer protein using a polymerase chain reaction-mediated site-directed mutagenesis. CETP deficiencies were studied in 554 Japanese subjects (370 men, 184 women) aged between 18 and 91 (mean 48.3 years). By this method, we detected one homozygote and 3 heterozygotes of the CETP deficiency.

Adult↗
PubMed1993

Angiotensin converting enzyme inhibitor, captopril, inhibits cardiac hypertrophy without changing collagen types and concentration in spontaneously hypertensive rats.

1. The effects of the ACE inhibitor, captopril, on collagen metabolism in spontaneously hypertensive rats (SHR) with cardiac hypertrophy was examined. Captopril (100 mg/kg per day) was administered in drinking water to 20 week old male SHR for 12 weeks. Collagen concentration was calculated from hydroxyproline content, and relative proportions of types I, III and V collagen were determined by non-interrupted SDS-polyacrylamide gel electrophoresis (SDS-PAGE). These parameters were examined in age and sex matched Wistar-Kyoto (WKY) rats, as well as in non-treated SHR, and compared with those of captopril-treated SHR. 2. Captopril significantly reduced both blood pressure (191 +/- 12.1 vs 146 +/- 11.2 mmHg, P < 0.01), and the ratio of left ventricular (LV) weight to bodyweight (BW; 2.38 +/- 0.17 vs 2.05 +/- 0.12 mg/g, P < 0.01). There were no significant differences in collagen concentration among WKY rats, captopril-treated SHR and non-treated 32 week old SHR. However, total collagen content in captopril-treated SHR reduced significantly compared with non-treated 32 week old SHR (16.8 +/- 2.0 vs 21.3 +/- 0.8 mg, P < 0.01). The relative proportion of type V collagen was significantly higher in both captopril-treated (58.6 +/- 3.4 vs 46.8 +/- 1.3%, P < 0.01) and non-treated 32 week old SHR (59.9 +/- 3.1 vs 46.8 +/- 1.3%, P < 0.01) compared with WKY rats. However, there were no significant differences between captopril-treated SHR and non-treated 32 week old SHR.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Biochemical remodeling of collagen in the heart of spontaneously hypertensive rats--prominent increase in type V collagen.

To determine how collagen is remodeled in the heart during the development of cardiac hypertrophy, the collagen concentration and the proportions of types I, III, and V collagen were analyzed in the hearts of 10-, 20-, 32-, and 40-week-old spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. The collagen concentration was calculated after the hydroxyproline content was measured and the proportions of types I, III, and V collagen were determined by non-interrupted SDS-polyacrylamide gel electrophoresis (SDS-PAGE). There was no significant difference between the collagen concentrations in 10-week-old SHR and WKY. At 20 weeks, the collagen concentration in the hearts of the SHR had decreased significantly (p < 0.01) when compared to that in the WKY, at 40 weeks, this concentration in SHR had increased significantly (p < 0.05) when compared to that in the WKY. Type V collagen in WKY increased with age and type I collagen in the 20- and 40-week-old WKY decreased significantly (p < 0.05) when compared to that in the 10-week-old WKY. However, the proportion of type I collagen in the 20-week-old WKY did not differ from that of the 40-week-old WKY. There was no significant difference between the proportions of the various types of collagen in 10-week-old SHR and those in age- and sex-matched WKY. However, the proportion of type V collagen in the 20- and 40-week-old SHR was significantly (p < 0.01) higher than that in age- and sex-matched WKY.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Evaluating coronary reperfusion during acute myocardial infarction in a canine model by gadolinium-DTPA-enhanced magnetic resonance imaging.

In previous studies, magnetic resonance imaging (MRI) using contrast agents was found to be useful in distinguishing reperfused infarcts from nonreperfused infarcts. However, there have been only a few detailed studies using consecutive MR images for the assessment of myocardial reperfusion during an acute myocardial infarction and also no studies have been performed using a percutaneous transluminal coronary occlusion model (closed chest model). We induced acute myocardial infarction in dogs by occluding and then reperfusing the coronary artery with a balloon catheter. ECG-gated MR images were taken using the spin-echo technique before and after Gd-DTPA injection during both coronary artery occlusion and after reperfusion. We defined the intensity ratio (IR) as the signal intensity at the ischemic area divided by that at the nonischemic area on MR images and compared each image by the IR. Without Gd-DTPA, there was no difference between infarcted and normally perfused myocardium. Infarcted myocardium had a low signal intensity (IR = 0.68 +/- 0.14) soon after Gd-DTPA injection. This difference diminished with time. After reperfusion the infarcted myocardium had a high signal intensity (IR:1.76 +/- 0.34). We conclude that Gd-DTPA- enhanced MRI can distinguish reperfused from nonreperfused infarcts soon after Gd-DTPA administration.

Animals↗
PubMed1993

[The characteristic flow of the superior vena cava in cardiac tamponade: a case report].

A case of cardiac tamponade showing the characteristic flow pattern in the superior vena cava is reported. An 80-year-old man was admitted to our hospital complaining of anorexia and general fatigue. We observed a paradoxical pulse of 25 mmHg, dilatation of the jugular vein, and marked cardiomegaly on chest radiography. A two-dimensional echocardiogram demonstrated a massive pericardial effusion and collapse of the right atrial and right ventricular walls. On the basis of his echocardiograms and clinical signs, we diagnosed his condition as cardiac tamponade. Pulsed Doppler echocardiograms showed two-peaked flow in the superior vena cava in systole. To assess the diagnostic significance of this characteristic flow pattern, the superior vena cava flow was recorded simultaneously with the intrapericardial pressure and the right atrial pressure. The intrapericardial pressure was higher than the right atrial pressure in early systole. After pericardial drainage, these pressures became reversed and the two-peaked flow disappeared. The two-peaked flow is attributed to collapse of the right atrial wall caused by the higher intrapericardial pressure than the right atrial pressure. The superior vena cava flow represents the right heart filling dynamics in cardiac tamponade.

Aged↗
PubMed1992

Apolipoprotein E1 Lys-146----Glu with type III hyperlipoproteinemia.

During the screening of samples obtained from 5 individuals with type III hyperlipidemia, we identified a variant of apolipoprotein (apo) E which exhibited a discrepancy in apo E phenotype showing the E3/E1 isoform on isoelectric focusing (IEF) analysis and E3/E3 on gene analysis. Sequence analysis of the DNA of the proband that was amplified by PCR and subcloned, revealed a single substitution of one lysine (AAG) for one glutamic acid (GAG) at position 146, thereby adding two negatively charged units to apo E3. This defect had been described only for apo E1 to date (Mann et al. (1989) Clin. Res. 37, 520A (abstract)). In this case, PCR-mediated site-directed mutagenesis was used to identify the structural alterations forming the abnormal E1 genotype in the proband's family. Purified apo E1 Lys-146----Glu showed less than 10% of binding activity to apo B, E receptor on human skin fibroblasts compared with apo E3. This substitution demonstrates that Lys-146 is essential for the binding of apo E to the receptor.

Adult↗
PubMed1992

Gly145 to Arg substitution in HBs antigen of immune escape mutant of hepatitis B virus.

A Japanese child born to an HBeAg-positive carrier mother received anti-HBs immunoglobulins and a plasma-derived HBs vaccine with a poor anti-HBs-antibody response. The child, who is now 3 years old, is presently suffering from chronic hepatitis with unusual serological findings that are positive for HBsAg, anti-HBs and HBeAg, since being infected with a measles virus at 12 months of age. The nucleotide sequences of the S region of HBV DNA obtained from the patient, the mother and an HBeAg-positive brother were completely identical except for one nucleotide at position 587 (mother and brother: guanosine, patient: adenosine), giving an amino acid change: Gly - greater than Arg at position 145 of the major HBs protein.

Amino Acid Sequence↗
PubMed1992

Mutational analysis of an actin-binding site of cofilin and characterization of chimeric proteins between cofilin and destrin.

Cofilin and destrin are two related low molecular weight mammalian actin-binding proteins. Cofilin is an F-actin side-binding and pH-dependent actin-depolymerizing protein, and destrin is a pH-independent actin-depolymerizing protein. We have introduced a few point mutations within an actin-binding sequence of cofilin. Biochemical analyses of these mutant proteins have clearly shown that Lys112 and Lys114 of cofilin are crucially but differently involved in its interaction with actin and phosphatidylinositol 4,5-bisphosphate. This is the first example among actin-binding proteins whose point mutations inactivate their interaction with actin in vitro. We have also made and characterized a series of chimeric proteins between cofilin and destrin to identify the regions responsible for the pH dependence and the F-actin side binding activity of cofilin. Our results suggest that a central region consisting of 42 amino acid residues and a carboxyl-terminal quarter of cofilin are both involved in regulation of the pH-dependent actin depolymerizing activity and the activity to bind along F-actin.

Actin Depolymerizing Factors↗
PubMed1992

Xenopus MAP kinase activator: identification and function as a key intermediate in the phosphorylation cascade.

MAP kinase is thought to play a pivotal role not only in the growth factor-stimulated signalling pathway but also in the M phase phosphorylation cascade downstream of MPF. MAP kinase is fully active only when both tyrosine and threonine/serine residues are phosphorylated. We have now identified and purified a Xenopus MAP kinase activator from mature oocytes that is able to induce activation and phosphorylation on tyrosine and threonine/serine residues of an inactive form of Xenopus MAP kinase. The Xenopus MAP kinase activator itself is a 45 kDa phosphoprotein and is inactivated by protein phosphatase 2A treatment in vitro. Microinjection of the purified activator into immature oocytes results in immediate activation of MAP kinase. Further experiments using microinjection as well as cell free extracts have shown that Xenopus MAP kinase activator is an intermediate between MPF and MAP kinase. Thus, MAP kinase activator plays a key role in the phosphorylation cascade.

Animals↗
PubMed1992

Localization of herpes simplex virus type 1 in sebaceous glands of mice.

The distribution of HSV-1 during the development of zosteriform skin lesions in SCID mice was analyzed by immunofluorescence and electron microscopy. The virus initially appeared within certain keratinocytes, sometimes surrounded by keratinocytes whose surfaces were also positive for the antigens, in the lower epidermal layers including the hair follicles, and then extended upward to the entire epidermis and downward to the sebaceous glands 1-2 days later, when no macroscopic skin lesion was seen. The affected epidermal cells subsequently degenerated and lost their viral antigens within a day, when the zosteriform lesion then became evident. This was followed by a degeneration of the dermis. The sebaceous glands eventually degenerated in 10 days, but some glands in the necrotic skin areas preferentially retained HSV-1. The horizontal spread of the virus in the epidermis beyond the first invaded dermatome occurred much later. In mice passively immunized with specific immune serum, viral antigens were observed even 20 days after the infection in sebaceous glands in necrotized areas. Therefore, HSV-1 appears to spread first via the extracellular fluid among the keratinocytes after being shed from nerve endings, and then produces a successive degeneration of the affected keratinocytes which may prevent any further extension of horizontal viral spread. The pilosebaceous apparatus is possibly acting as a site not only for the replication of HSV-1 with a delayed cytopathic effect, but also as an area that is temporarily sheltered from host defense mechanisms.

Animals↗
PubMed1992

Effects of non-collagenous proteins on the formation of apatite in calcium beta-glycerophosphate solutions.

The effects of the non-collagenous proteins; osteonectin, bone Gla protein and dentine phosphoprotein, on the formation of apatite were studied in calcium beta-glycerophosphate solutions containing catalytic amounts of alkaline phosphatase under physiological conditions. In the system used, calcium phosphate precipitates de novo at levels of supersaturation precisely determined through the enzymatic hydrolysis of beta-glycerophosphate. At 1.7 mM of calcium beta-glycerophosphate, calcium phosphate precipitated when inorganic phosphate accumulated to about 1.4 mM. In the presence of the proteins, however, a greater accumulation of inorganic phosphate was needed for calcium phosphate to precipitate, suggesting that a higher degree of supersaturation, though still a slight undersaturation with respect to dicalcium phosphate dihydrate, is required for calcium phosphate to precipitate in the presence of the proteins. At the same protein (micrograms/ml) concentration, dentine phosphoprotein was approximately four times as effective as bone Gla protein, which was about twice as effective as osteonectin in delaying precipitation. The proteins also retarded subsequent crystal growth, with apatite formed in the presence of the more inhibitory proteins having the smallest crystals, especially in width.

Alkaline Phosphatase↗
PubMed1992

Effects of niceritrol on levels of serum lipids, lipoprotein(a), and fibrinogen in patients with primary hypercholesterolemia.

Thirty-three consecutive unselected patients with primary hypercholesterolemia received niceritrol 1.5 g daily for 12 weeks, with the effect of administering divided dose (twice daily (b.i.d.) and three times daily (t.i.d.)) evaluated. The serum concentrations of lipoprotein(a) (Lp(a)), lipids, the major apolipoproteins (apo), cholesteryl ester transfer activity and fibrinogen were determined before and after treatment. The b.i.d. and t.i.d. regimens each significantly reduced the serum levels of total cholesterol and triglyceride. The mean changes in serum lipids and lipoproteins did not differ significantly between the two groups. After 12 weeks of treatment, there was a significant decrease in total plasma cholesterol, triglyceride, low density lipoprotein cholesterol, apo A-II, apo B and fibrinogen and an increase in the high density lipoprotein cholesterol levels. Although the serum level of Lp(a) did not change in every patient, niceritrol significantly reduced the serum Lp(a) level in those with an initially high level of Lp(a) (greater than or equal to 20 mg/dl).

Adult↗