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Biomedical subjects

T Kuwahara

Publications and source records attributed to T Kuwahara.

At least 73 records · Page 4Linked to original sources
PubMed1998

Atrial natriuretic peptide as a preload depressor in acute renal failure secondary to congestive heart failure.

The present study was undertaken to verify the hypothesis that infusion of atrial natriuretic peptide (ANP) might lower preload and be beneficial in the treatment of pulmonary congestion even without a diuresis in patients with acute renal failure (ARF) secondary to severe congestive heart failure (CHF). We studied 22 patients with ARF secondary to CHF. The mean age of the patients (14 men and 8 women) was 72 years (range 36 to 85 years). Seven of the patients had dilated cardiomyopathy, ten had ischemic heart disease, and five had valvular heart disease. ANP was infused intravenously and the following data before and 1 hour after the start of ANP infusion were recorded; urinary output, systemic blood pressure (SBP), pulmonary blood pressure (PBP), right atrial pressure (RAP), cardiac index (CI), heart rate (HR), and arterial blood oxygen partial pressure. Diastolic PBP were employed as pulmonary capillary wedge pressure. Urinary output did not change. Mean SBP decreased from 92 to 85 mmHg (p < 0.05), and mean PBP decreased from 34 to 28 mmHg (p < 0.01). Mean RAP decreased from 11 to 9 mmHg (p < 0.01) and diastolic PBP decreased from 25 to 19 mmHg (p < 0.01). HR did not change significantly and CI increased 2.4 to 2.5 mi/min/m2 (p < 0.05). Arterial blood oxygen partial pressure increased significantly from 71 to 82 mmHg (p < 0.05). In conclusion, ANP decreased preload and improved arterial blood oxygen partial pressure, though diuretic response to ANP is attenuated in ARF secondary to CHE. Infusion of ANP will be very beneficial in cases in which dyspnea and pulmonary edema due to elevation of preload are the principal clinical problems.

Acute Kidney Injury↗
PubMed1998

Activation of 1-nitropyrene by nitroreductase increases the DNA adduct level and mutagenicity.

1-Nitropyrene (1-NP) is a mutagenic nitro compound in the environment. We studied correlations between the mutagenicity of 1-NP for three strains of Salmonella typhimurium, the activity of bacterial nitroreductases and the amount of 1-NP-derived DNA adducts. Bacterial strains used in this study were S. typhimurium strains TA98, nitroreductase-less mutant TA98NR and YG1021 carrying a nitroreductase-producing plasmid. The mutagenicity of 1-NP was measured using the Ames assay, and the nitroreductase activities of these strains were assayed by quantification of 1-aminopyrene produced from 1-NP. The DNA adducts were measured by the 32P-postlabeling method. Among the three bacterial strains, strain YG1021 was the highest in mutagenicity of 1-NP, the nitroreductase activity and the DNA adduct level. However, S. typhimurium strain TA98NR had the lowest values of these three parameters. Nitroreductase activity, DNA adduct level and mutagenicity were strongly correlated with each other. These results indicate that bacterial nitroreductase plays an important role in forming the DNA adducts, and that the higher the adduct level the higher the level of mutagenicity.

DNA Adducts↗
PubMed1998

Marked attenuation of mitral regurgitation by stent implantation: a patient with unstable angina.

A 69-year-old woman was admitted because of increase of chest pain and dyspnea. Systolic murmur of Levine III/VI was heard. Electrocardiography showed ST depression caused by ischemia. Echocardiography revealed severe mitral regurgitation (MR) and inferoposterior hypokinetic wall motion. Left ventriculography revealed the presence of MR (II/IV). Coronary angiography showed severe organic stenosis of the right coronary artery. Based on these findings, the diagnosis was severe papillary muscle dysfunction caused by unstable angina. The lesion of the right coronary artery was successfully stented with a Palmaz-Schatz stent. During balloon inflation, the v wave of the pulmonary capillary pressure curve was greatly elevated. After the stent implantation, ST depression was normalized and MR improved dramatically. Therefore, we suppose that acute MR was induced by temporary papillary muscle dysfunction, and could be relieved with coronary angioplasty.

Aged↗
PubMed1998

Direct evidence of impaired cardiac sympathetic innervation in essential hypertensive patients with left ventricular hypertrophy.

UNLABELLED: Increased sympathetic nervous activity has been proposed as one of the causes of left ventricular hypertrophy (LVH) associated with hypertension. However, the precise relationship is not fully understood. METHODS: To elucidate the relationship between myocardial sympathetic nervous activity and LVH in patients with essential hypertension EHT), we performed 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 49 patients with EHT and 17 normotensive control subjects. Sympathetic innervation of the left ventricle was evaluated using SPECT, and the whole heart uptake of the tracer was quantitatively assessed as the heart-to-mediastinum uptake ratio on both the early (15-min) and delayed (5-hr) images. Myocardial washout rate (MWR) of the tracer from 15 min to 5 hr after the isotope administration was also calculated. The left ventricular mass index (LVMI) was determined echocardiographically. RESULTS: In 49 hypertensive patients, there was a negative correlation between LVMI and heart-to-mediastinum uptake ratio on both the early and delayed images (r=-0.55, p < 0.0001; r=-0.63, p < 0.0001, respectively). In addition, there was a positive correlation between the LVMI and MWR of 123I-MIBG in these hypertensive patients (r=0.59, p < 0.0001). As for the regional uptake of the tracer, there was no significant difference between control subjects and hypertensive patients without cardiac hypertrophy, but a significant decrease of the uptake in the inferior and lateral regions was observed in hypertensive patients with cardiac hypertrophy. CONCLUSION: Patients with EHT had decreased accumulation and increased MWR of 123I-MIBG in proportion to the degree of LVH. Hypertensive patients with cardiac hypertrophy had impaired sympathetic innervation in the inferior and lateral regions of the left ventricle.

3-Iodobenzylguanidine↗
PubMed1997

Kidney-specific expression of a novel mouse organic cation transporter-like protein.

Using the signal sequence trap method, we have cloned a novel 12-membrane-spanning transporter-like protein, termed renal-specific transporter (RST), from the mouse kidney. RST is a 553-amino-acid protein highly homologous to recently cloned organic cation transporters, e.g. it is 30% identical to rat organic cation transporter I at the amino acid level. Northern blot analysis has revealed that the RST gene is expressed abundantly and specifically in the kidney. In situ hybridization analysis has shown that RST gene expression is restricted to the renal proximal tubule, where various organic cations such as endogenous catecholamines and choline or clinically used cationic drugs are known to be actively excreted.

Amino Acid Sequence↗
PubMed1997

Effect of intestinal bacteria on formation of azoxymethane-induced aberrant crypt foci in the rat colon.

The effect of intestinal bacteria on formation of azoxymethane (AOM)-induced aberrant crypt foci (ACF) and DNA adducts in the rat colon was investigated. Male Sprague-Dawley rats were administered cultures of Lactobacillus acidophilus, Bifidobacterium adolescentis, Bacteroides fragilis, Escherichia coli and Clostridium perfringens for five weeks and given injections of AOM at 15 mg/kg body weight at the first and second weeks. The number of ACF five weeks after the start of the experiment was decreased in the rats treated with the cultures or culture supernatants of L. acidophilus and C. perfringens. The half-life of O6-methylguanine (O6-meG) in the L. acidophilus group was shorter than that in the GAM broth group. The half-life of 7-methylguanine did not differ among the groups. These results suggest that the metabolite(s) of L. acidophilus and C. perfringens inhibit(s) the ACF formation in rats treated with AOM and that the inhibitory effect of L. acidophilus is due to the enhanced removal of O6-meG from the colon mucosal DNA.

Animals↗
PubMed1997

Genome analysis of Bacteroides by pulsed-field gel electrophoresis: chromosome sizes and restriction patterns.

The chromosomal DNAs of nine strains of seven Bacteroides species including B. fragilis, the type species of the genus Bacteroides, were digested with rare-cutting restriction enzymes I-Ceu I, Not I, and Asc I and analysed by pulsed-field gel electrophoresis. The genome sizes of B. fragilis, B. distasonis, B. eggerthii, B. ovatus, B. thetaiotaomicron, B. uniformis, and B. vulgatus were determined to be 5.3, 4.8, 4.4, 6.9, 4.8, 4.6, and 5.1 Mbp, respectively. B. distasonis and B. vulgatus, and also B. uniformis and B. eggerthii, showed similar I-Ceu I restriction profiles. I-Ceu I cut B. uniformis and B. eggerthii genomes into four, B. ovatus into five, B. fragilis and B. thetaiotaomicron into six, and B. distasonis and B. vulgatus into seven fragments. On the basis of genome size, restriction profile, and I-Ceu I fragment number, a phylogenetic tree of the Bacteroides species was proposed. This was in overall agreement with the previous phylogenetic tree obtained by 16S rRNA data, with the exceptions of B. distasonis and B. ovatus.

Bacteroides↗
PubMed1997

Quantitative analysis of myocardial ischemia by technetium-99m sestamibi exercise scintigraphy: a new method for change rate mapping.

In order to quantitatively assess the extent and severity of myocardial ischemia by Tc-99m sestamibi exercise myocardial scintigraphy, we developed a new method of change rate (CR) mapping and examined its efficiency. CR was calculated to divide the counts per pixel in the stress polar map by that in the rest polar map at each corresponding pixel. The CR map showed the CR values at each pixel. To correct the differences between the stress and rest images for the dose of Tc-99m sestamibi administered, the mean counts per pixel in the stress polar map and the rest map were adjusted to the same level. Regarding the regions in which the CR value was less than 1 as ischemia, we compared the abilities of the CR map and the polar map to detect coronary artery stenosis in 5 patients with angina pectoris. The sensitivity for coronary artery stenosis was 80% in the CR map, and 40% in the polar map. The specificity for both was 75%. We concluded that the CR map was effective in assessing the extent and severity of myocardial ischemia in Tc-99m sestamibi exercise myocardial scintigraphy.

Adult↗
PubMed1997

A 41-year-old woman with protein S deficiency and diffuse proliferative lupus nephritis: is protein S deficiency associated with a hyperinflammatory response?

A 41-year-old woman with complete protein S (PS) deficiency who developed diffuse proliferative lupus nephritis is reported. She was referred to our hospital with nephrotic syndrome and thrombocytopenia. Her medical history included colorectostomy and amputation of the extremities because of repeated thrombotic episodes during her teens without any evidence of systemic lupus erythematosus. The diagnosis of PS deficiency was made from the patient's clinical course, undetectable serum PS in either the active or inactive form, normal protein C activity, and no evidence of the antiphospholipid syndrome. However, there was no definitive family history. A depressed level of complements and a positive antinuclear acid antibody suggested a diagnosis of systemic lupus erythematosus. The patient had a rapidly progressive course and died of disseminated intravascular coagulation. An autopsy showed generalized thrombotic lesions and diffuse proliferative lupus nephritis on both ordinal light and immunoperoxidase microscopy. Our observations suggest that PS-deficient patients may have a hyperinflammatory response.

Adult↗
PubMed1997

[A Rathke's cleft cyst with a moving mass in the cyst].

We reported a case of Rathke's cleft cyst (RCC) with a moving mass in the cyst. A fifty-eight-year-old woman complaining of headache was admitted to our hospital. She suffered from hyponatremia, hypothalamic hypopituitarism, but did not show any neurological deficits, nor visual field nor visual acuity disturbance. MRI revealed an intrasellar cyst including a mass shadow and the cyst did not compress the hypothalamus. Interestingly, this mass moved gradually from the floor to the posterior wall of the sella turcica according to changes in position from standing to supine. We operated to remove the cyst partially by transsphenoidal approach. Xanthochromic fluid flowed out from the cyst. In addition, a brownish globular mass, 6 mm in diameter, existed within the cyst without connection to the surrounding tissue. Pathological findings showed that the capsule consisted of cuboid epithelium and was partially stratified, which confirmed the diagnosis of Rathke's cleft cyst. However, the mass was homogeneously stained with H.E., containing no cells, cellular debris, nor connective tissue. PAS stain was negative. Though we could not clarify the material in the cyst, this case is very rarely one of Rathke's cleft cyst. This case demonstrated the possibility of hypothalamic hypopituitarism in spite of the cyst being almost located in the sella turcica. We surmise that a cyst near the stalk of the pituitary gland, even if it is not so large, might compress the portal vein, and thus the function of hypothalamus-pituitary axis.

Craniopharyngioma↗
PubMed1997

[Chinese herbs nephropathy in the Kansai area: a warning report].

In 1993, Vanherweghem and his associates reported cases of rapidly progressive renal interstitial fibrosis in young women who were administered a slimming regimen including Chinese herbs. Subsequently, similar cases have been reported. In Japan, especially in the Kansai area, several cases of Chinese herbs nephropathy have already been reported. We experienced a patient suffering from Chinese herbs nephropathy (CHN), and further detected aristolochic acids from the Chinese herbs taken by the patient. Aristolochic acids are known to be causative agents of CHN. The danger of CHN should be noted as soon as possible and drugs containing aristolochic acids should be prohibited.

Aristolochic Acids↗
PubMed1997

[Mitral prosthetic valve replaced twice due to repeated prosthetic valve endocarditis: a case report].

A 38-year-old man was admitted to our hospital for detailed examination of fever, cough and yellow sputum. At the age of 32, be had mitral prosthesis for the first time, because of mitral regurgitation due to mitral valve prolapse. Four years previously, he had again undergone mitral prosthetic valve replacement due to prosthetic valve endocarditis due to staphylococcus epidemidis. This occasion, staphylococcus aureus was isolated by arterial blood culture. Transesophageal echocardiography detected vegetation attached to the mitral prosthetic valve and paravalvular leakage. The diagnosis was prosthetic valve endocarditis. He underwent a third mitral prosthetic valve replacement. Detection of the source of infection was difficult only by transthoracic echocardiography, and immediate transesophageal echocardiography seemed mandatory to diagnose bacterial endocarditis.

Adult↗
PubMed1997

[Traditional remedy-induced Chinese herbs nephropathy showing rapid deterioration of renal function].

A 19-year-old female was referred to our hospital for azotemia and anemia. She had been taking a health food for atopic dermatitis for about three years. Urinalysis showed proteinuria, glycosuria and microscopic hematuria. Generalized aminoaciduria was observed. Moreover, severe anemia, azotemia, hypokalemia and hypophosphatemia were also observed. Renal biopsy specimen disclosed hypocellular interstitial fibrosis and degeneration of the proximal tubular epithelial cells. No remarkable changes were observed in the glomeruli. Aristolochic acid was detected in the health food. From these findings, she was diagnosed as having Chinese herbs nephropathy (CHN). Although consumption of the food intake was stopped, her renal function deteriorated rapidly. Previously, we reported that certain kinds of Chinese herbal drugs contain aristolochic acid and that the drugs should be prohibited if aristolochic acid is identified. However, we experienced a patient of CHN arising from traditional remedy, which was not proved to be safe. It should be awared that health foods may contain aristolochic acid.

Adult↗
PubMed1996

Experimental infusion phlebitis: importance of titratable acidity on phlebitic potential of infusion solution.

The titratable acidity of infusion solutions has never been taken into account in infusion phlebitis. This study aims to clarify the importance of titratable acidity on the phlebitic potential of infusion solutions. Solutions with different titratable acidity (from 0.16 to 12 mEq/L) were infused into the ear veins of 6 rabbits for 6 h at 10 mL/kg/h, and the veins were later examined histopathologically. Even at pH 4.0, a commercial 10% glucose solution scarcely caused any changes because of its very low titratable acidity (0.16 mEq/L). A 10% glucose solution with its titratable acidity adjusted to 3 mEq/L (pH 4.3) with citrate and NaOH, however, caused phlebitic changes in all 6 rabbits, and adjusting the titratable acidity to 12 mEq/L (pH 4.4) increased the degree of phlebitis. On the other hand, a 10% glucose solution with a pH of 5.4 and a titratable acidity of 6 mEq/L caused slight phlebitic changes in half the rabbits. These results suggest that 1) the titratable acidity of infusion solutions is important to the phlebitic potential when the pH is low, 2) when the pHs are similar, the phlebitic potential of infusion solutions depend on the titratable acidity, and 3) the phlebitic potential of infusion solutions can not be estimated by pH or titratable acidity alone.

Journal Article↗
PubMed1996

Characteristic chewing parameters for specific types of temporomandibular joint internal derangements.

In order to determine if there are characteristic chewing patterns for specific types of TMJ internal derangements, chewing was analyzed in 210 TMD patients with unilateral internal derangement (MDR early, 40; MDR late, 41; MD, 80; MDP, 49), and in 94 TMD patients without internal derangement, and 10 asymptomatic subjects with normal TMJ imaging. Each internal derangement subgroup demonstrated a significantly restricted envelope of motion and a reduced chewing velocity especially when they chewed on their normal TMJ side. Comparing different types of internal derangement, the MDR early group demonstrated relatively normal chewing, while the MDR late, MD and MDP groups showed severely impaired chewing movements. Among these three groups, the MD group demonstrated the most impairment, followed by the MDP and the MDR late groups. These results demonstrate that different types of internal derangement have specific impairments upon chewing, suggesting use of this analysis as a diagnostic tool.

Adult↗
PubMed1996

The influence of postoperative treatment on the results of TMJ meniscectomy. Part II: comparison of chewing movement.

In order to evaluate the influence of different types of postoperative treatments on the results of TMJ surgery, chewing movement recorded postoperatively was compared in 32 patients with unilateral total meniscectomy, 42 patients with partial meniscectomy with disk repair, and 10 normal subjects. Postoperative treatment was of three different types depending on its strategy. It was found that postoperative treatment had a significant positive effect on the results of both total and partial meniscectomy. Postoperative treatment which included both physical medicine modalities and dental treatment demonstrated better results than only dental treatment or no postoperative treatment. However, none of these studied techniques could recover chewing movement to the normal range.

Adult↗
PubMed1996

Effect of continuous passive motion on the results of TMJ meniscectomy. Part I: Comparison of chewing movement.

In order to evaluate the therapeutic effect of continuous passive motion (CPM) on the outcome of TMJ meniscectomy, chewing movement was analyzed before surgery and six months after surgery in 31 patients receiving CPM (CPM group), 26 patients without CPM (non-CPM group), and in ten normal subjects. The surgical procedure consisted of either total meniscectomy or partial meniscectomy with disk repair. It was found that chewing in patients receiving CPM was closer to the normal range than for patients in the non-CPM group. The results from the CPM group demonstrated chewing parameters for patients with partial meniscectomy returning to the normal range. However, for the patients with total meniscectomy, some parameters remained out of the normal range. From these results, we conclude that CPM has a positive influence on the outcome of TMJ surgery.

Adult↗