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Biomedical subjects

K Kawamura

Publications and source records attributed to K Kawamura.

At least 289 records · Page 16Linked to original sources
PubMed1994

Isolation and partial characterization of crystal matrix protein as a potent inhibitor of calcium oxalate crystal aggregation: evidence of activation peptide of human prothrombin.

In order to clarify the characteristics of crystal matrix protein (CMP), which exhibits a remarkable affinity for calcium oxalate crystals and may be important in stone pathogenesis, we have isolated CMP from macromolecular matrix substances of newly-formed calcium oxalate crystals. Purification of CMP consisted of calcium oxalate crystal formation, dissolution of crystals, electrodialysis, anion exchange chromatography and high-performance liquid chromatography. CMP showed the protein band of 31 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of CMP was identical to that of human prothrombin. Both anti-CMP polyclonal antibody and anti-human prothrombin antibody cross-reacted well with human prothrombin and CMP in Western blotting. Its amino acid composition and its molecular weight of 31 kDa strongly suggest that CMP is the activation peptide of human prothrombin.

Adult↗
PubMed1994

The favourable effect of cyclophosphamide pulse therapy in the treatment of massive pulmonary haemorrhage in systemic lupus erythematosus.

Pulmonary haemorrhage (PH) is a rare but very serious complication of systemic lupus erythematosus (SLE) and the treatment is still controversial. Some authors showed the effectiveness of methylprednisolone pulse therapy for PH, although its effect was often transient. A 12-year-old Japanese girl with lupus nephritis and recurrent massive PH in SLE was treated with methylprednisolone pulse therapy. The effect on PH was transient and she needed three cycles within a month and side-effects developed. Pulse therapy with cyclophosphamide, synchronized with plasmapheresis, was tried. Thereafter she did not experience PH for 7 months, whereas lupus nephritis did not improve. Pulse cyclophosphamide would be effective for life threatening massive PH in SLE patients.

Child↗
PubMed1994

Effect of herbimycin A, an inhibitor of tyrosine kinase, on protein tyrosine kinase activity and phosphotyrosyl proteins of Ph1-positive leukemia cells.

Herbimycin A, a benzoquinonoid anasamycin antibiotic, preferentially inhibited the in vitro growth of Ph1-positive leukemia cell lines. On the other hand, genistein, which was developed as an inhibitor of receptor-type tyrosine kinase, and other protein kinase inhibitors showed no selective inhibition of Ph1-positive leukemia cell growth. Herbimycin A also displayed an abrogative effect on the transformation of murine hematopoietic cells by transfection with a bcr/abl oncoprotein-expressing retroviral vector. The antitumor action of herbimycin A on Ph1-positive leukemia cells is related to an inhibition of activity of bcr/abl protein tyrosine kinase and a subsequent reduction of the constitutive phosphotyrosyl proteins, however, the antibiotic has no effect on the expression of bcr/abl mRNA and oncoprotein. Therefore, herbimycin A may provide an important insight into the oncogenic action of bcr/abl oncoprotein and the future development of oncoprotein-targeted therapeutic agents.

Antibiotics, Antineoplastic↗
PubMed1994

Kinetic and mechanistic analysis of dinucleotide and oligonucleotide formation from the 5'-phosphorimidazolide of adenosine on Na(+)-montmorillonite.

The rate constants for the condensation reaction of the 5'-phosphorimidazolide of adenosine (ImpA) to form dinucleotides and oligonucleotides have been measured in the presence of Na(+)-volclay (a Na(+)-montmorillonite) in pH 8 aqueous solution at 25 degrees C. The rates of the reaction of ImpA with an excess of adenosine 5'-monophosphoramidate (NH2pA), P1,P2-diadenosine 5',5'-pyrophosphate (A5'ppA), or adenosine 5'-monophosphate (5'-AMP or pA) in the presence of the montmorillonite to form NH2pA3'pA, A5'ppA3'pA, and pA3'pA, respectively, were measured. Only 3',5'-linked products were observed. The magnitude of the rate constants decrease in the order NH2pA3'pA > A5'-ppA3'pA > pA3'pA. The binding of ImpA to montmorillonite was measured, and the adsorption isotherm was determined. The binding of ImpA to montmorillonite and the formation of higher oligonucleotides is not observed in the absence of salts. Mg2+ enhances binding and oligonucleotide formation more than Ca2+ and Na+. The rate constants for the oligonucleotide formation were determined from the reaction products formed from 10 to 40 mM ImpA in the presence of Na(+)-montmorillonite using the computer program SIMFIT. The magnitudes of the rate constants for the formation of oligonucleotides increased in the order 2-mer < 3-mer < 4-mer ... 7-mer. The rate constants for dinucleotide and trinucleotide formation are more than 1000 times larger than those measured in the absence of montmorillonite. The rate constants for the formation of dinucleotide, trinucleotide, and tetranucleotide are 41,2.6, and 3.7 times larger than those for the formation of oligo(G)s with a poly(C) template. The hydrolysis of ImpA was accelerated 35 times in the presence of the montmorillonite. The catalytic ability of montmorillonite to form dinucleotides and oligonucleotides is quantitatively evaluated and possible pathways for oligo(A) formation are proposed.

Absorption↗
PubMed1994

Increased susceptibility to oxidative DNA damage in regenerating liver.

Spontaneous and hepatocarcinogen (2-nitropropane, 2-NP)-induced levels of 8-hydroxy-2'-deoxyguanosine (oh8dG) in the nuclear DNA of regenerating liver [24, 48, 72 h and 7 days after partial hepatectomy (PH)] of male Sprague-Dawley rats were analysed for the verification of a hypothesis that the high susceptibility of proliferating hepatocytes to DNA damage is related to the well-known high susceptibility to carcinogens after PH. Interestingly, the spontaneous level of nuclear oh8dG in regenerating liver was significantly decreased (P < 0.01) at 48 h after PH (1.05 +/- 0.31 oh8dG/10(5)dG) compared with the level in normal rats (1.90 +/- 0.41). 2-NP induced an oh8dG level of 4.49 +/- 0.86 in nuclear DNA of rat liver without PH. However, in rats administered 2-NP (injections were performed 6 h before each sacrifice) after PH, the oh8dG level was significantly higher at 24 h (5.45 +/- 1.41, P < 0.05), 48 h (5.85 +/- 0.88, P < 0.01) and 72 h (5.67 +/- 1.07, P < 0.05) after PH than those with 2-NP exposure alone. Therefore, it is suggested that nuclear DNA in proliferating hepatocytes is in a stage susceptible to exogenous attack by 2-NP, and consequently this phenomenon might be related to the induction of hepatocarcinogenesis after PH.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1994

Inductions of oxidative DNA damage and mesothelioma by crocidolite, with special reference to the presence of iron inside and outside of asbestos fiber.

Inductions of oxidative DNA damage (oh8dG) in vitro and peritoneal mesothelioma in rats (F344, female) were compared between crocidolite (CR) and de-ironized crocidolite [DCR, washed by HCl and ethylenediamine tetraacetic acid (EDTA)] to verify the hypothesis that reactive oxygen species contribute to carcinogenesis, focusing on the role of iron present inside or outside of the CR. The yield of oh8dG was 14.6 oh8dG/10(5)dG in CR and 30.2 in DCR under simple incubation with DNA. In the incubation systems added several chemicals and H2O2, DCR induced higher levels of oh8dG than CR. Especially, the addition of Fe2O3 and H2O2 to DCR increased oh8dG in DNA depending on the Fe2O3 concentration, however, this tendency was not observed in the same system of CR. Surprisingly, 7 out of 10 rats died within 2 days after the injection of 10 mg of Fe2O3 following the DCR injection (5 mg/rat), showing necroses of hepatocytes from the surface of each lobe where CR and Fe2O3 particles had been deposited together. There was no death in other groups of rats. One year after the i.p. injection of CR (5 mg/rat, single injection), mesotheliomas were found in all rats administered DCR and Fe2O3 (2 mg/rat, once a week, for 35 weeks), in 4 rats of DCR alone (n = 10), in 5 rats of CR alone (n = 10) and in none of the rats administered Fe2O3 alone (n = 10). Therefore, present results indicate that the induction of oxidative DNA damage changed even when the same type of asbestos was washed by chemical treatment, and Fe2O3 promoted the development of mesothelioma which was induced by DCR.

Animals↗
PubMed1994

Epitopes and biological activities of two monoclonal antibodies to platelet integrin alpha IIb beta 3.

We have developed two monoclonal antibodies (MAbs), B6A3 and C4G1. The whole molecules of the two MAbs inhibited in vitro human platelet aggregation induced by either ADP, collagen or thrombin, and their F(ab')2 fragments inhibited ex vivo platelet aggregation induced by ADP in monkey. The concentrations necessary for complete inhibition were 5 and 1 microgram/ml for B6A3 and C4G1, respectively. The Fab fragment of C4G1 but not B6A3 inhibited platelet aggregation. B6A3 and C4G1 bound to activated platelets with dissociation constants of 0.25 and 0.82 nM, respectively. B6A3 recognized an epitope on beta 3, which was sensitive to reduction and alkylation of cystine residues, and C4G1 recognized a conformational epitope on the alpha IIb beta 3 complex, which was sensitive to EDTA. The binding of fibrinogen to activated platelets was inhibited by both MAbs. However, the binding of fibrinogen to isolated alpha IIb beta 3 was inhibited by the whole molecule of C4G1 but not B6A3, although both MAbs bound to the isolated alpha IIb beta 3. The binding of these MAbs to the isolated alpha IIb beta 3 was not inhibited by either Arg Gly Asp Ser (RGDS) or fibrinogen gamma-peptide. In addition, B6A3 but not C4G1 bound to human endothelial cells. These MAbs should contribute to the elucidation of the mechanism of platelet aggregation.

Amino Acid Sequence↗
PubMed1994

Converting enzyme inhibition improves congestion and survival in hypertensive rats with high-output heart failure.

The effects of angiotensin-converting enzyme (ACE) inhibitors in high-output heart failure have not yet been well established. We evaluated the effects of lisinopril (3 mg/kg/day) on hemodynamics, neurohormones, and survival in 10-week-old spontaneously hypertensive rats (SHR) with aortocaval fistula. Sham-operated treated and untreated SHR served as controls. Cardiac output (CO) was determined by thermodilution method, and renal blood flow (RBF) was assessed by laser-Doppler flowmetry. In sham-operated SHR, 2-week treatment with lisinopril decreased blood pressure (BP), left ventricular (LV) weight, and total peripheral resistance (TPR) (p < 0.01 each) and increased RBF and plasma renin activity (PRA) (both p < 0.05); CO and LV end-diastolic pressure (LVEDP) were unchanged. Fistula creation induced biventricular hypertrophy and high-output heart failure [increased LVEDP, CO, pulse pressure, and plasma norepinephrine (NE) and decreased RBF] with congestive signs (ascites, tachypnea). Lisinopril decreased LVEDP (p < 0.01), increased RBF, prolonged survival (both p < 0.05), and prevented ascites (0 vs. 46%) and increased PRA (p < 0.05) and attenuated the increase in plasma NE. Heart weight, BP, and CO were not affected by lisinopril. Thus, lisinopril ameliorated congestion and improved survival in SHR with fistula without compromising cardiorenal hemodynamics. Venous and renal dilatation and attenuation of vasoconstrictive systems may have contributed to the beneficial effects.

Animals↗
PubMed1994

Lichen sclerosis et atrophicus with prominent telangiectasia.

Lichen sclerosis et atrophicus is characterized by the development of well demarcated, depigmented macules with epidermal atrophy. Hemorrhage occurs occasionally; however, telangiectasia is seldom remarkable. We studied a case of lichen sclerosis et atrophicus with striking telangiectasia which involved a 62-year-old male who was suffering from this disorder on his upper back. An initial lesion had been excised 15 years earlier. Thirteen years after the original surgery, he noticed a similar skin eruption accompanied by telangiectasia that had recurred around the surgical scar. We present here a detailed description of this case and provide a short review of the literature.

Atrophy↗
PubMed1994

The peritoneal equilibration test variables in pediatric CAPD patients.

The peritoneal equilibration test (PET) is generally accepted as a valuable tool in individualizing continuous ambulatory peritoneal dialysis (CAPD) treatment schedules in adults. However, the classification of peritoneal permeability as described by Twardowski is not available for children due to differences in peritoneal transport abilities. In this paper, we report the results of the PET for 20 patients aged from 1.5 to 24 years (mean 10.3 years), who started CAPD therapy at age 0-15 years, using Twardowski's standardized technique. D/P creatinine (dialysate to plasma ratio of creatinine at 4 h), D/D0 glucose (the ratio of dialysate glucose at 4 h dwell time to dialysate glucose at 0 dwell time), and the residual volume (RV) in the abdominal cavity were calculated. The mean and standard deviation values for D/P creatinine and D/D0 glucose were of a higher permeability level than those reported in Twardowski's data. Furthermore, a significant correlation of creatinine and glucose with fluid drainage ability of the peritoneum were observed. A large amount of RV (425 +/- 125 mL/m2) was detected in the patients' peritoneal cavity and this had a significant correlation with dialysate leak occurrences. The authors suggest that the RV would be an indicator for leaks and especially latent leaks. The cause of a large RV is unknown, but there is a probability that drainage volume and transport rates of metabolites decrease because the concentration of the instilled dialysate is immediately diluted by a large RV within the peritoneum.

Adolescent↗
PubMed1994

Importance of mechanical damage to urinary red blood cells by the glomerular basement membrane.

The reasons for morphological changes of urinary red blood cells (RBC) in patients with glomerulonephritis are still controversial. In order to evaluate the importance of mechanical damage by the glomerular basement membrane (GBM), we examined urinary RBC taken from the patients with two different diseases which have characteristic GBM changes. Urinary RBC taken from 20 patients with Alport syndrome and nine with thin GBM disease were examined using a scanning electron microscope. Nineteen out of the 20 patients (95.0%) with Alport syndrome showed 'glomerular type', while five of the nine patients (55.6%) with thin GBM disease showed 'glomerular type'. These results suggest that more complicated GBM abnormalities cause more severe RBC distortion. Therefore, we conclude that mechanical damage by the GBM may be the major factor in dysmorphism of urinary RBC.

Erythrocytes↗
PubMed1994

Influence of RF capacitive heating on the alpha 1-adrenergic receptors of rat prostates.

The aim of this study was to find out the influence of radiofrequency (RF) capacitive heating on the alpha 1-adrenergic receptor of rat prostates. The prostates of 30-week-old Wistar rats were submitted to a 1-hour single session of RF capacitive heating at 45 degrees C. The ventral prostates that were submitted to heating were compared to those of other rats that were not submitted to heating. In order to determine the density of alpha 1-adrenergic receptors in rat ventral prostates, binding assays for alpha 1-adrenergic receptor were performed with [3H]prazosin in membrane preparations. The receptor density in the control group was 27.07 +/- 3.75 fmol/mg protein. The alpha 1-adrenergic receptor density (Bmax) in the thermotherapy group was 17.91 +/- 5.15 fmol/mg protein. A remarkable decrease in the density of alpha 1-adrenergic receptors was observed in the rat prostates of the thermotherapy group. In conclusion, the present results demonstrate that heating the rat prostate by RF capacitive heating damages the alpha 1-adrenergic receptors.

Animals↗
PubMed1994

The effect of pravastatin on prevention of restenosis after successful percutaneous transluminal coronary angioplasty.

Numerous attempts have been made to prevent late restenosis after successful percutaneous transluminal coronary angioplasty (PTCA), but there is still no effective treatment. This report describes the effect of an oral lipid-lowering agent, pravastatin, on restenosis after successful PTCA. Sixty-six patients who underwent successful elective PTCA were assigned to a pravastatin-treated group (Group 1, n = 29) or an untreated group (Group 2, n = 37) in a prospective and randomized fashion. Pravastatin (5 mg or 10 mg twice a day) was given to Group 1 patients from day 3 after the procedure. Selective coronary angiography was repeated 3 to 5 months later, or sooner if the patient developed angina pectoris. The serum cholesterol level was decreased significantly in Group 1 (from 215.7 +/- 44.3 mg/dl to 181.2 +/- 30.3 mg/dl, p < 0.001), but not in Group 2 (from 191.9 +/- 30.8 mg/dl to 191.8 +/- 33.3 mg/dl, p = ns), at the time of repeat coronary angiography. However, there were no differences between the groups with regard to the recurrence of angina, the need for repeat PTCA, or restenosis, as assessed by quantitative analysis of coronary cineangiograms. These results suggest that oral pravastatin therapy does not effectively prevent late restenosis after successful PTCA by this mode of administration.

Administration, Oral↗
PubMed1994

Left ventricular function of the heart regressed by nifedipine in spontaneously hypertensive rats.

Left ventricular (LV) performance of the pharmacologically regressed heart in hypertension is still unclear. We compared LV function of the heart regressed by nifedipine with that of the hypertrophied heart in spontaneously hypertensive rats (SHR). Nifedipine (30 mg/kg/day in food) was given to 15-week-old male SHR for 20 weeks (n = 12). Age- and sex-matched SHR served as controls (n = 12). LV catheterization was performed using a micromanometer and cardiac output was determined by the thermodilution method. Hemodynamic studies were performed after washout of nifedipine (24 h), when blood pressure had returned to the untreated level. Peak pumping ability was assessed during acute volume loading with saline. Nifedipine significantly decreased blood pressure in conscious animals (222 +/- 11 to 201 +/- 12 mmHg, p < 0.01) and reduced LV weight (1.20 +/- 0.07 to 1.07 +/- 0.05g, p < 0.01). After washout of nifedipine, LV systolic and end-diastolic pressures, dp/dtmax and cardiac output determined under pentobarbital anesthesia were similar in the treated and untreated groups. Peak pumping ability during acute preload elevation was also similar in the 2 groups. Plasma norepinephrine was unaltered, and plasma renin activity was significantly lower in the treated rats (p < 0.05). These results indicate that nifedipine regressed LVH with a minimal reduction of blood pressure and without evidence of neurohumoral activation or volume retention. In conclusion, LV function of the heart regressed by nifedipine was preserved after a spontaneous rise in blood pressure and during acute preload elevation.

Animals↗
PubMed1994

Excellent prognosis of Japanese patients with chest pain and normal or nearly normal coronary arteries--2- to 13-year follow-up of 274 patients after coronary cineangiography.

Although the prognosis of patients with chest pain and normal coronary arteries is reportedly good in the Western literature, it is unclear in Japan. The purpose of this study was to examine the natural history of 274 consecutive patients with chest pain and normal or nearly normal coronary arteries, and to determine whether the possibility of minor coronary artery disease has clinical implications as a prodromal factor of other heart diseases. Six of the patients died during the mean observation period of 6 years (74.5 +/- 35.4 months): 2 cancer, 3 cerebro-vascular accident, and 1 renal failure death. Three additional patients suffered from nonfatal cerebro-vascular accidents. Eleven patients were readmitted for evaluation of chest pain, and 4 of these were diagnosed as having vasospastic angina. Progression of significant coronary artery disease was not detected in these 11 patients with repeated coronary angiography. None of the patients in this study developed fatal or nonfatal myocardial infarction. A small number of patients (36/240, 15.0%) continued to suffer from chest pain. None of the patients developed cardiomyopathies or valvular heart diseases. Our observations indicate that the prognosis of chest pain with normal or nearly normal coronary arteries is better than that presented in the Western reports.

Adult↗
PubMed1994

[Pharmacokinetic and clinical evaluation of cefozopran in the pediatric field].

We conducted pharmacokinetic and clinical studies on cefozopran (CZOP, SCE-2787), an aminothiadiazolmethoxyiminoacetamido cephalosporin, and obtained the following results. 1. Concentrations in serum/excretion in urine We studied pharmacokinetic in children upon intravenous bolus injection and 30-minute intravenous drip infusion in single doses of 10 and 20 mg/kg. Upon intravenous bolus injection, mean serum concentrations 30 minutes after administration of 10 and 20 mg/kg were 27.8 and 52.3 micrograms/ml, respectively, and half-lives were 2.01 and 2.02 hours, respectively. Upon 30-minute intravenous drip infusion, mean serum concentrations on completion of the drip infusions of 10 and 20 mg/kg were 36.8 and 70.3 micrograms/ml, respectively, and half-lives were 1.74 and 4.11 hours, respectively. Their urinary recovery rates in the first 8 hours after administration were higher than 67.0% in the former regimen and between 23.2 to 98.0% in the latter. 2. Clinical results 54 patients were treated with CZOP for 32 cases of pneumonia, 11 cases of bronchitis, 3 cases of cervical lymphadenitis, 1 case of purulent tonsillitis, 2 cases of phlegmon, 2 cases of enterogastritis and 3 cases of urinary tract infections. CZOP gave "excellent" or "good" responses in 53 cases. 1 case of urinary tract infection showed fair response. Diarrhea was observed in 1 case. Abnormal laboratory test results were noted in 9 patients including elevations of eosinophils, GOT and GPT. In no cases the treatment had to be discontinued.

Adolescent↗