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Biomedical subjects

A Hirayama

Publications and source records attributed to A Hirayama.

At least 37 records · Page 2Linked to original sources
PubMed2001

Detection of Treponema denticola in atherosclerotic lesions.

We examined 26 atherosclerotic lesions and 14 nondiseased aorta specimens to detect the periodontopathogenic part of the bacterial 16S rRNA locus by PCR. Treponema denticola sequence of the 16S rRNA locus was found in 6 out of 26 DNA samples (23.1%) from the formalin-fixed, paraffin-embeded atherosclerotic lesions obtained during surgery but not in any of the 14 nondiseased aorta samples from deceased persons. Utilizing immunofluorescence microscopy, we observed aggregated antigenic particles reacting with rabbit antiserum against T. denticola in thin sections of the PCR-positive samples, but we could not detect any reacting particles in the PCR-negative thin sections.

Adult↗
PubMed2001

Circadian variation of the onset of acute myocardial infarction in the Osaka area, 1998-1999: characterization of morning and nighttime peaks.

The onset of acute myocardial infarction (AMI) shows characteristic circadian variations; that is, a definite morning peak related to biologic rhythms and a vague nighttime peak related to socioeconomic factors. The recent economic recession in Japan may change the circadian variation, especially the nighttime peak. This study evaluated the recent circadian variation of AMI in Osaka and specified the patient subgroups showing either a morning or nighttime peak predominantly. Of 1,609 consecutive patients with AMI registered from April 1998 to January 2000, 1,252 whose onset of AMI was definitely identified were studied. The day was divided into six 4-h periods with a morning peak between 08.01 h and 12.00h, and nighttime peak between 20.01 h and 24.00h. When subgroup analysis was performed, female patients aged 65 years or more showed a morning peak alone and male patients aged less than 65 years with an occupation and the habits of cigarette smoking and alcohol intake showed a nighttime peak alone. Thus, in Osaka nighttime socioeconomic factors may currently be more potent triggers of AMI than the morning surges in younger male workers who smoke and drink.

Adult↗
PubMed2001

Heterogeneity of prognosis in adult IgA nephropathy, especially with mild proteinuria or mild histological features.

OBJECTIVE: The present study was undertaken to clarify the clinical course and prognosis of adult patients with primary IgA nephropathy (IgAN), especially with mild proteinuria or mild histological alternations. PATIENTS AND METHODS: A population of 735 IgAN patients whom we were able to observe for more than two years was examined. RESULTS: A total of 115 patients (15.6%) was on dialysis during the observation period. The overall 5-year renal survival rate was 92.0%. On the other hand, 166 patients (22.6%) were in clinical remission. A group with mild proteinuria included 197 patients (26.8%). Forty-seven patients of this group showed minor glomerular abnormalities, whereas 12 patients with mild proteinuria showed severe mesangial involvement. Three patients with mild proteinuria were on dialysis during the observation period, whose proteinuria was increased during the clinical course. A group with minor glomerular abnormalities included 82 patients (11.2%). Forty-seven patients of this group showed mild proteinuria, of whom 12 patients showed moderate proteinuria. However, three patients with minor glomerular abnormalities who were not on dialysis showed loss of renal function. CONCLUSION: These results indicated the heterogeneity of the course and prognosis in IgAN. Even if a patient's initial clinical or histological findings are comparatively mild, strict follow-up management is needed.

Adolescent↗
PubMed2001

[Le Duc-Camey procedure as a method of ureteroileal implantation on augmentation cystoplasty in patients with myelodysplasia].

PURPOSE: We investigated the results of Le Duc-Camey procedure as a method of ureteroileal implantation on augmentation cystoplasty in patients with myelodysplasia. MATERIALS AND METHODS: A total of 14 patients (25 renal units) underwent ureteroileal implantation with Le Duc-Camey procedure on augmentation cystoplasty. The possible causes of complications concerning ureteroileal implantation that developed during the postoperative observation were classified as preoperative factors and postoperative factors.: The preoperative factors were the causative disease required ureteroneostomy, the grade of preoperative VUR, and the ureteral diameter at the anastomosis with the ileum.: The postoperative factors were the volume, and the compliance of the urinary bladder, and the maximum intravesical pressureled by the peristalsis of the utilized intestine. RESULTS: With the mean observation period of 31.6 months, no complications developed but VUR observed in 4 renal units of 4 patients. The patients with VUR had a larger ureteral diameter at the anastomosis site to the ileum among the preoperative factors and a significantly larger maximum intravesical pressure led by the intestinal peristalsis among the postoperative factors when compared with the patients without VUR. CONCLUSION: Regarding ureteroileal implantation with Le Duc-Camey procedure on augmentation cystoplasty in patients with myelodysplasia. It seems necessary to consider some countermeasures for the dilated ureters and for the unexpected 2 elevation of intravesical pressure due to the peristalsis of the utilized intestine.

Adolescent↗
PubMed2001

[Screening methods in the detection of bladder cancer: comparison of nuclear matrix protein-22, bladder tumor antigen and cytological examinations].

We evaluated the utility of urinary parameters (Nuclear Matrix Protein-22: NMP-22, Bladder Tumor Antigen: BTA, and cytological examinations) for the diagnosis or post-therapeutic monitoring of bladder cancer. Thirty one tumor-bearing cases including 19 fresh cases and 40 tumor-free cases, were subjects of this study. Using identical voided urine samples, NMP-22, BTA and urinary cytology were examined. The mean values of NMP-22 (cut-off value is 12 U/ml) was 100.5 +/- 26.5 U/ml in the tumor-bearing group and 21.9 +/- 7.8 U/ml in the tumor-free group (p < 0.05): Sensitivity was 74.2%, and specificity was 67.5%. Sensitivity of BTA was 58.1%, and specificity was 97.5%. Only five cases were judged positive by urinary cytology: 16.1% in sensitivity and 100% in specificity. Thus, NMP-22 and BTA were more sensitive than urinary cytology. In conclusion, the new urinary parameters, NMP-22 and BTA, would be less invasive and useful as tumor markers of bladder cancer. NMP-22 seems suitable for screening before the diagnosis and BTA for the post-therapeutic follow-up study.

Adult↗
PubMed2000

Angiographic and clinical outcome of a new self-expanding intracoronary stent (RADIUS): results from multicenter experience in Japan.

The RADIUS coronary stent featuring a multisegmented slotted tube design and self-expanding nitinol delivery system has a high radial force and flexibility, uniform expansion, and contours to the shape of the vessel. Successful stent deployment was achieved in 104 stable angina patients (106 lesions; 44% LAD, 19% circumflex, and 37% RCA). Mean minimal lumen diameter (MLD) increased from 0.77 +/- 0.46 mm to 2.88 +/- 0.61 mm and mean percent diameter stenosis (% DS) decreased from 73 +/- 14% to 6 +/- 13% immediately after the procedure. At 6-month follow-up, two patients (2%) underwent urgent target revascularization, and cerebral bleeding occurred in one patient (1%). Angiographic follow-up was performed in 94 lesions (89%) and mean MLD and mean % DS were 2.08 +/- 0.92 mm and 30% +/- 24%, respectively. Stent restenosis (>50% diameter stenosis at follow-up) was observed in 16 (17%) of all lesions. The high success rate for stent deployment, low incidence of major adverse cardiac event, and lower restenosis rate after stent implantation indicate that the RADIUS stent is useful for coronary intervention.

Adult↗
PubMed2000

Influence of surface modifications to titanium on oral bacterial adhesion in vitro.

The influence of surface modifications to titanium on the initial adherence of Porphyromonas gingivalis ATCC33277 and Actinobacillus actinomycetemcomitans ATCC43718 was evaluated. Surface modifications were performed with dry processes including ion implantation (Ca(+), N(+), F(+)), oxidation (anode oxidation, titania spraying), ion plating (TiN, alumina), and ion beam mixing (Ag, Sn, Zn, Pt) with Ar(+) on polished pure titanium plates. Comparatively large amounts of P. gingivalis and A. actinomycetemcomitans adhered to polished titanium plates. The degree of P. gingivalis adhesion showed a positive correlation with surface energy and the amount of calcium-ion adsorption. Adherence of both P. gingivalis and A. actinomycetemcomitans increased on calcium-implanted surfaces compared with polished titanium surfaces, whereas adherence of P. gingivalis was remarkably decreased on alumina-coated surfaces. These findings indicate that titanium implants exposed to the oral cavity require surface modification to inhibit the adherence of oral bacteria, and that surface modification with a dry process is useful in controlling the adhesion of oral bacteria as well as ensuring resistance against wear.

Aggregatibacter actinomycetemcomitans↗
PubMed2000

Clinical use of lidocaine for control of stroke oedema in the posterior cranial fossa accompanied by acute hydrocephalus.

Intravenous Lidocaine, in combination with steroid and Mannitol was used in 17 critical cases to control posterior fossa stroke oedema with jeopardised upward or downward herniation. Lidocaine successfully provided time for observation to select 5 correct candidates out of 17, indicated for aggressive decompression surgery in addition to ventricular drainage for acute hydrocephalus. There is no 'Golden-Rule' for this situation but the use of Lidocaine has a place in the management of it.

Aged↗
PubMed2000

Sphingolipid biosynthesis by L-PDMP after rat MCA occlusion.

L-PDMP (L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol) exhibits stimulatory effects on glycosphingolipid biosynthesis and its neurotrophic actions in cultured neuron. The effects of intraperitoneal administration of L-PDMP on sphingolipid metabolism and behavioral changes in the rat following permanent occlusion of the left middle cerebral artery (MCA) were investigated. The L-PDMP treatment induced increases in glucosylceramide (ganglioside precursor) and sphingomyelin (SM) levels in the ischemic cerebral cortex, and improved acquisition of memory and learning in the Morris water maze task. The pharmacological effects of L-PDMP have been proposed to have a significant activity on promoting cell survival and improving neural functions.

Animals↗
PubMed2000

Urachal tuberculosis.

BACKGROUND: We report on an extremely rare case of urachal tuberculosis that was confirmed using a polymerase chain reaction test of paraffin-embedded material. METHODS/RESULTS: A 62-year-old man presented with pollakiuria. With a diagnosis of urachal abscess, the patient underwent en bloc resection of the cystic mass. A bacterial culture test of the content showed no organism. The histopathologic findings suggested urachal tuberculosis. The AMPLICOR polymerase chain reaction test by using paraffin-embedded sections revealed the existence of Mycobacterium tuberculosis in the resected tissue. The only positive finding in systemic screening examinations for tuberculosis was old tuberculosis scars in the upper right lung. It was supposed that hematogeneous spreading from the lung lesion may result in urachal tuberculosis after a long latent period. CONCLUSIONS: Although urachal tuberculosis is an extremely rare condition, tuberculosis must always be kept in mind when observing any infectious diseases.

Abscess↗
PubMed2000

Hemodialysis does not influence the peroxidative state already present in uremia.

Hemodialysis (HD) patients are exposed to high oxidative stress, however, the nature of this stress is still unclear. In this study, we employed a specific lipid peroxidative product, phosphatidylcholine hydroperoxide (PCOOH), and evaluated the peroxidative effect of end stage renal disease by measuring thiobarbituric acid reactive substances (TBARS) and PCOOH in both plasma and erythrocyte membrane. We also surveyed plasma TBARS and PCOOH before and after HD sessions thereby assessing oxidative stress by a single HD procedure. The plasma TBARS level of healthy controls was 2.9 +/- 0.4 nmol/ml. Those of HD patients before and after HD session were 5.1 +/- 1.4 and 3.1 +/- 0.5 nmol/ml, respectively, and the pre-HD plasma TBARS levels were significantly higher than those of controls and after HD. The plasma PCOOH concentration of patients before HD was 119.7 +/- 58.4 pmol/ml and was significantly higher than that of controls which was 88.6 +/- 14.3 pmol/ml. After HD, the plasma PCOOH level decreased to 103.2 +/- 36.0 pmol/ml, which was still significantly higher than that of controls. In erythrocytes, the PCOOH level of patients was 259.3 +/- 105.4 nmol/g RBC and was significantly higher than that of controls with 88.6 +/- 32.0 nmol/g RBC. Analyzed with respect to the cause of renal disease, the polycystic kidney disease patients showed significantly lower plasma PCOOH levels than the others. These results suggest that there is an increase of lipid peroxidation in both plasma and erythrocytes of HD patients, though this oxidative stress was not brought about by HD.

Erythrocyte Membrane↗
PubMed2000

Morphological study of the femur in osteopetrotic (op/op) mice using microcomputed tomography.

Osteopetrosis is an inherited metabolic disorder in which normal bone remodelling is inhibited. Its primary cause is considered to be disruption of the functional balance between osteoblasts and osteoclasts as well as a reduction in the quantity of osteoclasts. The purpose of this study was to observe morphological characteristics of the femur in osteopetrotic (op/op) mice, in which the pathogenic mechanism of osteopetrosis has been shown to operate, using microcomputed tomography (micro-CT), in addition to macro-anatomical observations. Previously, micro-CT has been used mainly for morphometry of a small portion of cancellous bone. However, with recent improvements it has become possible for three-dimensional (3D) observations of bone using slightly larger samples to be made. In this study, the accuracy of reconstructed 3D images of the femur produced by micro-CT was confirmed by comparison with the original femur. In addition, an arbitrary cross-section could be displayed on the screen for detailed examination of its internal structure, and the volume percentage of trabecular bone in a particular region of interest could be measured in three dimensions. The results of this study revealed that the femur was smaller and malformed in the op/op mouse compared with the controls, and the differences were greater at the age of 18 weeks than at 5 weeks. In the control mice, bone marrow occupied a large space in the centre of the body of the femur, whereas this area was occupied by calcified bone tissue in the mutant mice. Moreover, when 3D bone density was measured in the region of interest, the value was greater in the mutants than in the controls at both 5 weeks and 18 weeks of age. This study also showed that micro-CT can be applied to 3D morphometric analyses.

Animals↗
PubMed2000

[Coronary angioscopy in ischemic heart disease].

The validity of coronary angioscope was discussed in several clinical settings in this article. First of all, although smooth coronary surface was observed by coronary angiography after the intervention of chronic total occlusion, protrusion or thrombus observed by angioscope occupied the arterial lumen and closed the vessel lumen. After implantation of the stent, lumen was widely opened. Serial angioscopic observation revealed that the neointima became thick and non-transparent until 6 months and then became thin and transparent by 3 years after stent implantation. These findings suggested the validity of angioscope in coronary intervention. Second, coronary angioscope revealed the morphologic and pathologic characteristics of culprit lesions in patients with acute coronary syndrome. The thrombus was observed on the yellow plaque in the culprit lesion. The thrombus formed directly over the plaque was mainly white and red thrombus might be formed after the blood flow was disturbed by the white thrombus formed by the platelet aggregation. These findings imply the importance of anti-platelet therapy after acute coronary syndromes. Finally, the angioscope can detect the minimal changes of the plaque formation, progression and rupture, that is, the entire process of the atherosclerosis. The early detection of yellow plaque might be able to intervent mechanically or pharmacologically to prevent its rupture.

Angioscopy↗
PubMed1999

S-nitrosothiols are stored by platelets and released during platelet-neutrophil interactions.

Interaction between platelets and neutrophils is important in vascular injury. We have investigated the storage and release of nitric oxide (NO) by platelets interacting with neutrophils. Shear-activated platelets were added to neutrophils in suspension and both superoxide and peroxynitrite formations monitored by lucigenin- and luminol-enhanced chemiluminescence. In addition, intraplatelet S-nitrosothiols were measured by dichlorofluorescein fluorescence following displacement of NO by mercuric chloride. Addition of activated platelets to neutrophils caused free radical production and platelet-neutrophil rosette formation. Pretreatment of platelets with 20 microM S-nitrosoglutathione changed the balance between luminol and lucigenin chemiluminescence in favor of luminol, whereas S-nitrosoglutathione in platelet-free plasma did not produce these changes. This pattern was also observed both following inhibition of neutrophil NO synthase and in a neutrophil-free superoxide-generating system. Inhibition of platelet NO synthase decreased luminol and increased lucigenin chemiluminescence. These effects were reversed by L-arginine. Platelet activation increased intraplatelet S-nitrosothiols from 1.93+/-0.19 (mean +/- SD) to 4.9+/-1.10 x 10(-18) mol/platelet (P < 0.01); this increase halved following NO synthase inhibition, but was enhanced by approximately 220% following incubation with S-nitrosoglutathione. These results show that during shear stress platelets store S-nitrosothiols, which can be derived either endogenously from NO synthesis or exogenously by sequestration of S-nitrosoglutathione. Release of stored NO during platelet-neutrophil interaction alters the interaction of NO with superoxide and could modulate vascular inflammation.

Arginase↗
PubMed1999

Mechanism for abnormal thallium-201 myocardial scintigraphy in patients with left bundle branch block in the absence of angiographic coronary artery disease.

Patients with left bundle branch block (LBBB) often show abnormal images on exercise thallium (T1)-201 scintigraphy without evidence of significant coronary stenosis. We investigated the mechanism for this phenomenon. Six patients with LBBB and without significant coronary stenosis underwent T1-201 SPECT, ECG-gated SPECT imaging with Tc-99m-methoxyisobutyl-isonitrile (MIBI), and atrial pacing stress test. The % count amplitude in Tc-99m-MIBI images was calculated as [(maximal counts) - (minimal counts)]/(minimal counts) x 100. Though all patients had a low count in the septal and inferior wall in T1-201 SPECT images, there was no ischemic production of lactate during an atrial pacing stress test. Nevertheless, gated SPECT images showed attenuated septal activity during systole. In patients with LBBB, the ratios of % count amplitude at the septum to that at the lateral wall at rest (0.47 +/- 0.05, mean +/- SE) were significantly less than the controls (n = 5, 0.83 +/- 0.12, p = 0.014). In conclusion, these results suggest that abnormal T1-201 SPECT images of the septum in patients with LBBB are partially caused by impaired septal wall thickening during systole. Such an abnormal wall motion may reduce blood flow demands to the septum, resulting in reduction of coronary blood flow with little ischemia.

Bundle-Branch Block↗
PubMed1999

Process of carboxylation of glutamic acid residues in the gla domain of human des-gamma-carboxyprothrombin.

In the absence of vitamin K (VK) or in the presence of VK antagonists, hepatic VK-dependent carboxylase activity is inhibited and des-gamma-carboxyprothrombin (DCP) is released into the blood. We analyzed the number of glutamic acid (Glu) residues and their positions in the Gla domain (GD) of DCP to investigate the gamma-carboxylation mechanism of VK-dependent carboxylase. Several DCPs were found in each subject studied. The 10 Gla residues of human prothrombin were carboxylated in order from the N-terminal (residues 26, 25, 16, 29, 20, 19, 14, 32, 7 and 6). The process of Glu carboxylation seemed to proceed three-dimensionally from inside to outside the molecule.

Adult↗