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Biomedical subjects

C Nakamura

Publications and source records attributed to C Nakamura.

At least 55 records · Page 3Linked to original sources
PubMed1999

Reduced size of liquefaction necrosis of mitral annular calcification in chronic renal failure by using low calcium concentration hemodialysis.

A report is presented of a liquefaction necrosis of mitral annular calcification in a patient with chronic renal failure and secondary hyperparathyroidism who had been managed by hemodialysis for 11 years. The mass was echogenic with an echo-lucent area inside, high density on computed tomography and low intensity on magnetic resonance imaging. The uptake of gallium-67 (67Ga)-citrate and the bone agent technetium-99m-methylene diphosphate (99mTc-MDP) was seen in the mass. These findings were compatible with liquefaction necrosis of the mitral annular calcification. After treatment with low calcium concentration hemodialysis, the size of the mass reduced with disappearance of the echo-lucent area on the echocardiography and there was no uptake of 67Ga-citrate or 99mTc-MDP. Liquefaction necrosis might be the early and reversible form of mitral annular calcification. When a tumorlike echogenic mass at the base of mitral leaflets is seen in patients with predisposing factors for mitral annular calcification, consider the possibility of this specific form of mitral annular calcification in order to avoid any unnecessary surgical intervention.

Calcinosis↗
PubMed1999

Pseudoaneurysm of the left ventricle progressing from a subepicardial aneurysm.

A 56-year-old man presented with an inferior myocardial infarction and a huge pseudoaneurysm below the inferior surface of the left ventricle, which had progressed from a small subepicardial aneurysm over a 6-month period. Transthoracic echocardiography, Doppler color flow images, radionuclide angiocardiography, magnetic resonance imaging and contrast ventriculography all revealed an abrupt disruption of the myocardium at the neck of the pseudoaneurysm, where the diameter of the orifice was smaller than the aneurysm itself, and abnormal blood flows from the left ventricle to the cavity through the orifice with an expansion of the cavity in systole and from the cavity to the left ventricle with the deflation of the cavity in diastole. Coronary angiography revealed 99% stenosis at the atrioventricular nodal branch of the right coronary artery. At surgery the pericardium was adherent to the aneurysmal wall and a 1.5-cm orifice between the aneurysm and the left ventricle was seen. Pathological examination revealed no myocardial elements in the aneurysmal wall. The orifice was closed and the postoperative course was uneventful. Over-intense physical activity as a construction worker was considered to be the cause of the large pseudoaneurysm developing from the subepicardial aneurysm. These findings indicate that a subepicardial aneurysm may progress to a larger pseudoaneurysm, which has a propensity to rupture, however, it can be surgically repaired.

Aneurysm, False↗
PubMed1999

In vitro tests of 1,3-dithia-2-thioxo-cyclopent-4-ene to evaluate the mechanisms of its hepatoprotective action.

Some in vitro tests were performed using 1,3-dithia-2-thioxo-cyclopent-4-ene (DT827A) to evaluate its mode of action on hepatoprotection. Experiments with leucine, uridine and thymidine uptakes using L-132 cells showed no increase in leucine uptake, but did show a tendency toward increases in both uridine and thymidine uptakes, which suggested a stimulating effect on RNA and DNA synthesis in vitro. DT827A did not influence GSH levels in the HepG2 cultured cell system, and did not show inhibition of cytochrome P450 2El in microsomes obtained from mouse liver. There may be no possibility for DT827A to protect a liver injury through its influence on liver GSH levels and inhibiting metabolic activation of CCl4 in this in vitro system. However, the inhibitory effect of DT827A on lipid peroxidation was observed in vitro, the same as the observation in vivo. Furthermore, when DT827A was incubated with Alamar Blue in the presence of a mixture of mouse liver S9 and mitochondrial fractions for 20 hr, DT827A showed more reducibility than it did in a case of non-incubation, and it was suggested that DT827A would be metabolized in the S9-mitochondrial fraction in vitro to show an increase of Alamar Blue reducibility. The protective effect of DT827A on a liver injury is due neither to its influence on liver GSH levels nor inhibition of the metabolic activation of CCl4, but a possible mechanism of action for the DT827 series of compounds to indicate an antioxidative effect would be brought about by the role of the compounds as a radical scavenger as well as its reductive effect.

Animals↗
PubMed1999

[Catheter drainage of late cardiac tamponade guided by computed tomography].

Delayed cardiac tamponade is an unusual but serious complication of cardiac surgery. Echocardiography and computed tomography (CT) are well established methods for the detection of pericardial effusions. Catheter insertion guided by CT has been used to accomplish non operative drainage of symptomatic postoperative pericardial effusion in seven cases. These patients were grouped into four types according to distribution of the fluid. General pericardial effusion around the heart is classified as type 1, effusion adjacent to the right side of the heart as type 2 and left side as type 3, effusion localized only at the apex as type 4. CT imaging is useful not only to localize and assess the size of the effusions, but also to select the way of catheter insertion. As the fluid might be trapped in compartments, for instance right-sided or left sided type, investigation of the pericardial spaces is important in planning a catheter pericardiocentesis.

Aged↗
PubMed1999

[Methods of sleep induction for EEG recordings: comparison between three hypnotics and natural sleep].

We compared the effects of three oral hypnotics, monosodium trichloroethyl phosphate (MTP), chloral hydrate (CH), and pentobarbital calcium (PTB), to those of non-medication on wake-sleep states and sleep activation of epileptic seizure discharges. The subjects consisted of 410 epileptics and 171 non-epileptic outpatients (mean age: 12.5 years) of the Department of Pediatrics, Nagoya City University Hospital. Complete EEG records including awake and sleep states were obtained in 230/241 (95%) of patients with MTP, 20/22 (91%) of those with CH, 72/85 (85%) of those with PTB, and 225/233 (97%) of those without any hypnotics. There were no statistically significant differences in the effect of sleep induction among the four groups. Sleep activation effects were observed in 25% of patients with natural sleep and 35% of those with induced sleep. There was no statistical difference (p > 0.05). These results suggested MTP, CH, and PTB are useful hypnotics for sleep EEG recordings.

Adolescent↗
PubMed1999

[A patient with pulmonary alveolar proteinosis who underwent whole lung lavage under total intravenous anesthesia with propofol].

A 32-year-old male suffering from pulmonary alveolar proteinosis underwent whole lung lavage under one-lung ventilation and total intravenous anesthesia with propofol and fentanyl. The lung lavage was initially performed for the right lung, and for the left lung two weeks later. Spo2 and Pao2 declined at the time of lung degassing and drainage of lavage fluid (minimum values; Spo2 = 83%, Pao2 = 55.9 mmHg), and recovered on filling with the lavage fluid. Although pulmonary arterial pressure and central venous pressure were slightly increased at the time of unilateral lung filling, there was no marked change in arterial pressure, heart rate or cardiac output for lavage of either lung. % VC, DLCO and PaO2 markedly improved after whole lung lavage, from 26.0%, 5.84 ml.min 1.mmHg-1, and 61.9 mmHg in room air to 41.6%, 9.96 ml.min-1.mmHg-1, and 89.3 mmHg in room air, respectively. Since propofol does not inhibit hypoxic pulmonary vasoconstriction and is able to maintain a stable level of anesthesia, it is a useful anesthetic agent for whole lung lavage.

Adult↗
PubMed1998

PCR on cerebrospinal fluid to show influenza-associated acute encephalopathy or encephalitis.

BACKGROUND: Except for Reye's syndrome, influenza-associated acute encephalopathy or encephalitis is not universally recognised. We did a multicentre study of laboratory and clinical data for patients with influenza-associated acute encephalopathy or encephalitis. METHODS: In Nagoya, Japan, ten patients with acute encephalopathy or encephalitis associated with influenza-like illness were admitted to our hospitals between April, 1996, and March, 1997. We collected clinical, laboratory and serological data and assessed cerebrospinal fluid samples by PCR for influenza A and B. FINDINGS: Seven patients, aged 22 months to 4 years, had evidence of recent influenza infection, six with type-A/Hong Kong (H3N2) and one with type B. The first sign in the central nervous system appeared within 2 days of fever in all but one patient. The first sign of involvement of the central nervous system was generalised convulsions in all patients. Two patients died, one had sequelae, and four survived without sequelae. PCR for influenza type A was positive for five patients. INTERPRETATION: The results of PCR suggest that at least part of the influenza type A genome existed in the central nervous system. Influenza-associated acute encephalopathy or encephalitis in young children deserves wider recognition.

Acute Disease↗
PubMed1998

Interactions of chlorophyll a with synthesized peptide in aqueous solution.

The interactions between chlorophyll a and synthesized peptides have been studied using optical spectroscopy. Three 30-residue peptides are designed and synthesized: an amphiphilic peptide without histidine (L), an amphiphilic peptide with histidine (L/H) and a hydrophilic peptide (K/E). These peptide properties thereby allow us to examine the effect of the peptide hydrophobicity and/or histidine residue on pigment-peptide interactions. On mixing with peptides, chlorophyll a has a main absorption band in the Qy region with the maximum at 672 nm. For all three peptides, fluorescence patterns show that at a low concentration of the peptide (0.05 mM) in aqueous solution, the energy is transferred among various forms of the pigment. Only peptide L/H at high concentration (0.5 mM) in solution retains the Qy band of chlorophyll a at 672 nm, and the emission is that typically seen for the monomeric form of the pigment. The aggregation of chlorophyll a is suppressed most strongly in the presence of the peptides L/H. The results suggest that chlorophyll a is ligated to a histidine residue, located in the hydrophobic region of the peptides L/H, and in surrounded or shielded by the peptide alpha-helixes.

Amino Acid Sequence↗
PubMed1998

Redox properties of an H-subunit-depleted photosynthetic reaction center from Rhodopseudomonas viridis.

Recently, we reported that a H-subunit-depleted photosynthetic reaction center (RC-H) was purified from purple nonsulfer photosynthetic bacterium Rhodopseudomonas viridis (Rps. viridis) using a strong detergent sodium alkyl ether sulfate. We compared the redox properties of a native photosynthetic reaction center (RC) and RC-H of Rps. viridis. In RC-H prepared by our method, secondary quinone (QB) was removed while primary quinone (QA) was retained. Absorption spectrum of RC-H was similar to that of RC. After reconstitution of ubiquinone 10 into QB sites, RC-H showed electron transfer activity that was the same as that for native RC. This is the first report about the redox properties of RC-H of Rps. viridis.

Electron Transport↗
PubMed1998

Characteristic difference in gastrointestinal excretion of clarithromycin and roxithromycin.

Excretion characteristics of two new macrolides; clarithromycin and roxithromycin, into the intestinal and the gastric lumens was studied by in situ single-pass perfusion and loop methods in rats. Roxithromycin maintained higher serum levels than clarithromycin after their intravenous administrations at a dose of 5 mg kg(-1) each. Radioactivities of clarithromycin and roxithromycin exsorbed into the intestinal lumen were 8.6 and 18.9% of dose in 2 h, respectively, whereas clarithromycin and roxithromycin excreted into the bile were 28.4 and 5.9%, respectively. These results suggest that roxithromycin is transported mainly by exsorption across the intestinal membrane, whereas clarithromycin mainly by excretion through the biliary tract. On the other hand, radioactivities of clarithromycin and roxithromycin exsorbed into the gastric lumen were much less then those into the intestinal lumen and were 0.72 and 1.34% of dose in 4 h, respectively. Thus, the exsorption into the gastric lumen seems to be a minor route for the elimination of both macrolides. Consequently, the transport into the intestinal lumen via the intestinal membrane and/or the bile tract may play a significant role in the overall elimination of both macrolides.

Animals↗
PubMed1998

[Spontaneous splenic rupture after mitral valve replacement for infective endocarditis].

We report a successful treatment of massive bleeding due to spontaneous splenic rupture after mitral valve replacement. A 61-year-old man was admitted to our hospital for intermittent high fever. An echocardiogram demonstrated a large vegetation on the posterior cusp of the mitral valve and mitral regurgitation of moderate degree. Staphylococcus epidermidis was cultured from his arterial blood. He underwent a mitral valve replacement after 3 weeks of antimicrobiological therapy with penicillin G crystalline and minocycline hydrochloeide. The patient fell into hemorrhagic shock on postoperative day 11 after complaining dull pain on his left upper abdomen for 3 days. A computed tomography demonstrated a splenic rupture and massive hematoma in the retroperitoneum. A splenic arterial embolization was done before splenectomy. The blood and clot of 2800 g were sucked from peritoneal and retroperitoneal cavities. There were no mycotic aneurysms nor abscess but the torn capsule on the swelled and partially necrotic spleen. The patient discharged uneventfully on postoperative day 43. Infective endocarditis frequently causes splenic infarction but rarely splenic rupture. Anticoagulation therapy after mitral valve replacement might have emphasized the bleeding in the patient.

Endocarditis, Bacterial↗
PubMed1998

Effects of aluminum hydroxide and famotidine on bioavailability of tosufloxacin in healthy volunteers.

This study was designed to determine the influence of aluminum hydroxide and famotidine on the bioavailability of tosufloxacin. Coadministration of aluminum hydroxide reduced the bioavailability of tosufloxacin by 31.6% (P < 0.05). Famotidine did not alter tosufloxacin absorption. To avoid potential treatment failures, the concurrent use of tosufloxacin and aluminum hydroxide should be avoided altogether.

Adult↗
PubMed1998

Change in erythrocyte shape induced by cyclosporine administration.

In order to estimate the effect of the long term administration of cyclosporine (CsA) on the shape change of erythrocytes, erythrocyte shapes which are observed with a scanning electron microscope were classified according to the nomenclature of Bessis for stomatocyte-echinocyte shape transformation. As a result of observing the erythrocyte shape of fifty-six patients with kidney transplantation treated with CsA, the morphological index of the erythrocytes of patients significantly increased to 0.0835+/-0.0085*** in comparison with 0.0004+/-0.0051 of those from healthy volunteers (control) (***: p<0.001, ANOVA). Such transformations had no relation to the subjects' sex or age. On the other hand, the erythrocytes of patients administered more than 100 ng/ml of CsA and posttransplanted within less than two years were transformed by CsA from the state of discocyte to echinocyte. In rats, the morphological index of erythrocytes of rats treated with 3 mg/kg/d or 5 mg/kg/d of CsA significantly increased in comparison with rats treated with saline (control). Furthermore, the erythrocytes of two patients were observed in terms of shape before the treatment with CsA. In both patients, the echinocyte type of erythrocyte increased by treatment with CsA. In vitro, the morphological index of the erythrocytes incubated with plasma containing CsA significantly increased, to 0.459+/-0.066*** in comparison with 0.064+/-0.029 of the control. It is suggested from these results that CsA treatment induces the echinocyte type of erythrocyte.

Adult↗
PubMed1998

Protective effects of betamipron on renal toxicity during repeated cisplatin administration in rats and protective mechanism.

The protective effects of betamipron (BP, N-benzoyl-beta-alanine) against nephrotoxicity induced by repeated cisplatin injections were examined. The ratio of the kidney weight to body weight and the lipid peroxide level after treatment with cisplatin plus BP tended to be larger and lower than those after treatment with cisplatin plus alkaline solution, respectively. The blood urea nitrogen, serum creatinine and glutathione levels in the animals treated with cisplatin plus BP differed significantly from those in the animals treated with cisplatin plus alkaline solution. Furthermore, the mechanism of the preventive effects of BP was analyzed for cisplatin-induced nephrotoxicity. The concentration of cisplatin in the renal cortex significantly decreased with concomitant BP. BP inhibited the uptake of cisplatin into the renal cortex in a competitive manner in the same way as an anionic transport inhibitor, probenecid. The treatment with BP appears to be useful for the renal toxicity induced by repeated cisplatin administration.

Alanine↗
PubMed1998

[A case report of infective endocarditis with total rupture of the posterior papillary muscle after aortic valve replacement].

We reported a case with severe mitral regurgitation caused by total rupture of the posterior papillary muscle two days after aortic valve replacement. A 62-year-old man was transferred to our hospital with high fever and dyspnea with severe aortic regurgitation caused by infective endocarditis. The left heart failure occurred suddenly two days after the initial operation. Echocardiogram revealed massive mitral regurgitation and rupture of the posterior papillary muscle. He underwent emergent mitral valve replacement. Histological examination of the papillary muscle showed typical ischemic necrosis without inflammation. The postoperative course was uneventful. We suggested the papillary muscle rupture in this case may be due to coronary artery emboli occurred in association with infective endocarditis.

Aortic Valve↗
PubMed1998

Tissue factor and tissue factor pathway inhibitor in hemodialysis patients.

Tissue factor and tissue factor pathway inhibitor are important in extrinsic coagulation. We investigated their clinical significance in hemodialysis patients. We took blood samples, prior to initiation of routine hemodialysis, from 73 patients on hemodialysis (35 men and 38 women aged 56.1+/-11.7 years on dialysis for 82.1+/-61.0 months), and determined tissue factor and tissue factor pathway inhibitor levels by ELISA. In the patients the tissue factor level was 704.5+/-141.6 pg/ml and the tissue factor pathway inhibitor level was 44.5+/-23.3 ng/ml; both values were significantly higher than in normal controls (192.7+/-36.6 pg/ml and 18.6+/-5.7 ng/ml, respectively). In patients with shunt obstruction, tissue factor pathway inhibitor levels were significantly higher than in those without it. Therefore, the tissue factor pathway inhibitor level may be a marker of shunt obstruction.

Adult↗