Biomedical subjects

T Katoh

Publications and source records attributed to T Katoh.

At least 199 records · Page 11Linked to original sources

PubMed1998

Detection of a local slow potential preceding the surface QRS complex during non-preexcited impulse propagation--a phenomenon reflecting anterograde concealed conduction through the accessory pathway?

A case of Wolff-Parkinson-White (WPW) syndrome with several interesting electrophysiologic findings is presented. Although manifest preexcitation had not been documented in clinical routine check-ups for the 2 years before the ablation session, an intermittent preexcitation emerged after an initial unsuccessful radiofrequency current delivery directed at the subvalvular mitral annulus 1 cm distal from the subsequent successful ablation site. During intermittent manifestation of preexcitation, the following observations were made: (1) during manifest preexcitation, a possible Kent potential was recorded at the successful ablation site; (2) during non-preexcited impulse propagation, a local slow potential preceding the QRS complex (pre-QRS potential) was clearly observed at the same site; (3) the pre-QRS potential disappeared during orthodromic atrioventricular reciprocating tachycardia, spontaneous atrial premature contraction and after the subsequent successful ablation; and (4) when the pre-QRS potential was obvious, a small change in QRS morphology of the body-surface ECG was appreciable, compared with that during beats of negative pre-QRS potential. A comparable preceding component was also detected in a signal-averaged ECG. It is considered that the pre-QRS potential might be related to the anterograde concealed conduction through the accessory pathway.

Electrophysiology↗

PubMed1998

Low-dose basic fibroblast growth factor and vascular endothelial growth factor for angiogenesis in canine acute hindlimb insufficiency.

Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have shown strong angiogenetic effects in ischemic animals; however, whether such a beneficial effect could be achieved using low doses remains to be determined. The effects of identical low-level doses of these substances on the creation of collateral circulation in canine acute hind limb insufficiency were evaluated. Anesthetized dogs that had undergone left femoral artery occlusion received 20 microg (2 microg/kg) intravenous boluses of either bFGF or VEGF 3 times at 2-day intervals for the first week only, animals on vehicle saline injection served as controls. All groups, control (n=8), bFGF-treated (n=8), and VEGF-treated (n=6) underwent angiography, blood flow measurement (in ml/min) on the day of ligation (day 0), and at 7, 14 and 28 days, then underwent ischemic limb muscle biopsy at 28 days. Angiogenic-treated groups showed remarkable enhanced collateral circulation at 7 days, which was maintained up to 28 days, and the main collateral source artery of the angiogenic-treated groups dilated by 14 days. Many neovascularized arterioles in specimens of the angiogenic groups were recognized without any tissue edema or necrosis. Even low doses of bFGF or VEGF were enough to augment collateral circulation with no side-effects, and short treatment after acute ischemia was effective. Low-dose bFGF or VEGF may be therapeutical effective options in patients with acute lower limb vascular disease.

Animals↗

PubMed1998

[A follow-up study on renal tubular dysfunction in women living in the cadmium-polluted Jinzu River basin in Toyama, Japan. Part 1. Changes in the level of exposure to cadmium after soil replacement of polluted paddy fields and the related effects on the prognosis of renal tubular dysfunction].

A follow-up study on renal tubular dysfunction was carried out on 193 female inhabitants of the cadmium (Cd)-polluted Jinzu River basin and 40 reference subjects living in an adjacent area in 1994-95. They were 54 to 70 years old when the initial examination was conducted in 1983-84. In the Cd-polluted Jinzu River basin, extensive reclamation of polluted rice fields has been conducted since 1979; as a result, the average Cd concentrations in polished rice consumed by the subjects in the 1994-95 study (0.12 ppm in 1994, 0.14 ppm in 1995) were significantly lower than those in the 1983-84 study (0.26 ppm in 1983, 0.29 ppm in 1984). The average Cd levels in urine in the follow-up study (7.5 micrograms/g Cr. in 1994, 7.7 micrograms/g Cr. in 1995) were also significantly lower than those in the initial study (13.5 micrograms/g Cr. in 1983, 13.3 micrograms/g Cr. in 1984). However, the mean values for urinary excretion of beta 2-microglobulin (beta 2-m) (3.9 mg/g Cr. in 1994, 3.7 mg/g Cr. in 1995) and glucose (203 mg/g Cr. in 1994, 251 mg/g Cr. in 1995) in the follow-up study were significantly higher than those obtained at the initial examination (2.0 mg/g Cr. and 125 mg/g Cr. in 1983 and 1.1 mg/g Cr. and 78 mg/g Cr. in 1984 for beta 2-m and glucose excretion, respectively). The magnitude of increase in urinary excretion of beta 2-m and glucose in inhabitants of the Cd-polluted area was significantly higher than that of the inhabitants of the reference area. Moreover, an increase was observed in the prevalence of renal tubular dysfunction determined by urinary beta 2-m exceeding 10 mg/g creatinine and urinary glucose exceeding 150 mg/g creatinine only among inhabitants of the Cd-polluted area; it is noteworthy that 31 new cases of renal tubular dysfunction were observed in the follow-up study. These results indicate that renal tubular dysfunction among inhabitants of the Cd-polluted Jinzu River basin is irreversible and progressive, and many new cases of renal tubular dysfunction were also noted over a period of 11 years, despite the fact that Cd exposure had decreased over the past 11 years.

Aged↗

PubMed1998

Dose-dependent effects of dichloropropanol on liver histology and lipid peroxidation in rats.

A rare outbreak of acute hepatic damage in workers exposed to dichloropropanols (DCPs) was reported recently. The purpose of the present study is to examine the effects of DCPs on various organs, the dose dependency and the pathogenetic potential of DCP hepatotoxicity. A single intraperitoneal injection was given to six groups of rats with 0.2 ml of 20% ethanol (control), or 1/8 x, 1/4 x, 1/2 x, 1 x, and 2 x LD50 (0.11 ml/kg) of 1,3-dichloro, 2-propanol (DC2P) diluted in 20% ethanol. After blood samplings, all organs were subjected to histologic examinations with light and electron microscopes. Fresh liver tissues from further 4 control and 4 experimental rats sacrificed 6 hours after the injection of 20% ethanol and 1 x LD50 of DC2P were homogenized and subjected to evaluate lipid peroxidation, glutathione S-transferase activity and reduced glutathione contents in the liver. The rats administered with only ethanol or 1/8 and 1/4 LD50 of DC2P showed no serological or histopathological abnormalities. Marked elevation of serum glutamate pyruvate transaminase (SGPT) with a diffuse massive necrosis of the liver cells were noted in all rats of both the 1 x and 2 x LD50 groups, and irregular zonal necroses were found in 3 of 4 rats injected with 1/2 LD50. There were no serious toxic changes in other organs. Hepatic malondialdehyde level was significantly increased, associated with decreases of liver glutathione S-transferase activity and reduced glutathione content. It was concluded that the serious DC2P-toxicity was mainly found in the livers, dose dependently, and one of the causative mechanisms of this hepatotoxicity might be the lipid peroxidation.

Alanine Transaminase↗

PubMed1998

Class specific influence of dietary Spirulina platensis on antibody production in mice.

In the present study, we investigated antibody productions of IgA and other classes, such as IgE and IgG1, in mice as possible evidence of the protective effects of Spirulina toward food allergy and microbial infection. An increase of IgE antibody level in the serum was observed in the mice that were orally immunized with crude shrimp extract as an antigen (Ag group). The antibody level, however, was not further enhanced by treatment with Spirulina extract (SpHW). IgG1 antibody, on the other hand, which was increased by antigen administration, was further enhanced by Spirulina extract. It was noted that the IgA antibody level in the intestinal contents was significantly enhanced by treatment with Spirulina extract concurrently ingested with shrimp antigen, in comparison with that of the Ag group treated with shrimp antigen alone. An enhancement of IgA antibody production by Spirulina extract was also observed in culture supernatant of lymphoid cells, especially in the spleen and mesenteric lymph node from mice treated with Spirulina extract for 4 weeks before antigen stimulation. These results suggest that Spirulina may at least neither induce nor enhance allergic reaction such as food allergy dependent on an IgE antibody, and that when ingested both concurrently with antigen and before antigen stimulation, it may significantly enhance the IgA antibody level to protect against allergic reaction.

Animals↗

PubMed1998

[Minimally invasive cardiac surgery for aortic valve disease].

Recent surgical advances leading to good operative results have contributed to the trend to useminimally invasive approaches, even in cardiac surgery. Smaller incisions are clearly more cosmetically acceptable to patients. When using a minimally invasive approach, it is most important to maintain surgical quality without jeopardizing patients. A good operative visual field leads to good surgical results. In the parasternal approach, we use a retractor to harvest an internal thoracic artery in coronary artery bypass surgery. Retracting the sternum upward allows for a good surgical view and permits the use of an arch cannula rather than femoral cannulation. When reoperating for aortic valve repair, the j-sternotomy approach requires less adhesiolysis compared with the traditional full sternotomy. No special technique is necessary to perform aortic valve surgery using the j-sternotomy approach. However, meticulous attention must be paid to avoiding left ventricular air embolisms to prevent postoperative stroke or neurocognitive deficits, especially when utilizing a minimally invasive approach. Transesophageal echo is useful not only for monitoring cardiac function but also for monitoring the persence of air in the left ventricle and atrium. This paper compare as the degree of invasion of minimally invasive cardiac surgery and the traditional full sternotomy. No differences were found in the occurrence of systemic inflammatory response syndrome between patients undergoing minimally invasive cardiac surgery and the traditional technique. Therefore it is concluded that minimally invasive surgery for patients with aortic valve disease may become the standard approach in the near future.

Aortic Valve↗

PubMed1998

[Repair of left ventricular free wall rupture with GRF glue associated with acute myocardial infarction: report of a case].

Histopathological examination of a repair of left ventricular free wall rupture associated with acute myocardial infarction using GRF glue was reported. A 63-year-old male with cardiac rupture due to LMT total occlusion was referred to our ward after unsuccessful PTCA with institution of IABP and PCPS. Left ventricular rupture repair by GRF glue and xenograft pericardial patch with concomitant myocardial revascularization (SVG-LAD, CX) was performed under cardiopulmonary bypass. Hemostasis around the ventricular rupture was easily accomplished. Unfortunately, the patient died at 14 POD because of low output syndrome caused by broad myocardial infarction. At autopsy, rupture site was examined histologically and was revealed that GRF glue made a tight adhesion between patch and myocardium. Neither abnormal inflammatory cells nor giant cells were found. We concluded that GRF glue might be a effective histocompatibly in hemostasis for left ventricular rupture associated with acute myocardial infarction.

Cardiac Surgical Procedures↗

PubMed1998

Progressive hyperthermia during thoracoscopic procedures in infants and children.

We describe the development of progressive hyperthermia during thoracoscopic procedures in infants and children. Twelve patients (four infants and eight children) underwent closure of a patent ductus arteriosus using the video-assisted technique. A progressive increase in body temperature of more than 2 degrees C occurred in six of the patients during surgery. The increase in body temperature correlated inversely with body weight and directly with duration of surgery (r = -0.76, P = 0.003 and r = 0.68, P = 0.01, respectively). We found that the thoracoscope produces 28.5 joule.min-1 of constant energy in vitro. Our findings show progressive hyperthermia during thoracoscopic procedures, due to energy release from the thoracoscope. This could be a significant complication in infants undergoing prolonged operations.

Age Factors↗

PubMed1998

[MRI phase contrast flow measurement of portal vein: influence and compensation of respiratory motion and propriety of phase correction using background].

The purposes of this study were to (1) determine which condition, breath holding (BH) or quiet breathing (QB), is better for phase contrast (PC) measurement of the portal flow (PF); (2) assess the usefulness of respiratory compensation (RC), a technique that diminishes motion artifacts due to breathing, on PC flow measurement; and (3) evaluate the propriety of phase correction (PhC) using background for PC flow measurement. For purposes (1) and (2) respiratory simulation phantom (RSP) was measured, and PF measurements were performed in 6 healthy subjects (HS) and 53 patients. Thirty of the patients had liver cirrhosis (LC) and 23 did not. For purpose (3), flow measurements were carried out in the phantom and 6 HS. (1) In 6 HS, intra-subjective coefficients of variation (CV) were smaller under QB than under BH (p < 0.05). And PF in patients with LC was less than in those not under QB (p < 0.01). This difference was not statistically significant under BH. (2) In the RSP study PC flow measurement with high sort RC showed good reliability. (3) Intraobserver variation was smaller without PhC than with PhC (p < 0.05) in the HS study. It may be more useful to perform portal flow measurements under QB with RC and without PhC than with PhC or under BH.

Adult↗

PubMed1998

[Metastatic renal tumor originating from esophageal carcinoma: a case report].

We report a case of renal metastasis from esophageal carcinoma. The patient was a 74-year-old man, who had undergone an operation for esophageal carcinoma thirteen months previously. He was admitted to our clinic for examination of a right renal mass. Computed tomography (CT) revealed an irregular low density area in the right kidney and angiography showed a hypovascular tumor. Partial nephrectomy was performed. Histological examination revealed squamous cell carcinoma and the diagnosis was metastasis of esophageal carcinoma. Metastatic renal tumors are rarely encountered clinically and, to our knowledge, the present case is only the 16th clinical report of the renal metastasis of esophageal carcinoma in Japan. However, metastasis to the kidney is relatively common at autopsy. It is the fifth most common site of metastasis following the lungs, liver, bones and adrenals. Consequently, patients with malignancy should be followed up while keeping renal metastasis in mind.

Aged↗

PubMed1998

[Autonomic nervous function of the patients with neurally mediated syncope].

Although diagnosis of neurally mediated syncope (NMS) using head-up tilt (HUT) test has been established, the exact mechanism of NMS has not yet been elucidated. We evaluated beta and alpha-adrenergic function in NMS patients by pharmacological autonomic function test. The alpha-adrenergic sensitivity of NMS patients was significantly lower than that of control subjects. The patients who need low dose isoproterenol for provocation of syncope showed higher beta-adrenergic sensitivity than patients who developed syncope without isoproterenol. Thus, pharmacological autonomic function test was useful for evaluation of NMS patients.

Adolescent↗

PubMed1998

Examination of prognostic factors after resection of pulmonary metastasis of osteosarcoma by multivariate analysis.

Prognostic factors for the case of pulmonary metastasis of osteosarcoma was examined using the multivariate analysis. 1) The 3-year survival rate after operation of primary focus in 23 cases was 34.8% and the 5-year survival rate was 30.4%. The 3-year survival rate after the first operation of pulmonary metastasis was 30.4% and the 5-year survival rate was 12.2%. No deaths attributed to operation were found. 2) Gender, age, histological type, solitary or multiple pulmonary metastasis, laterality, number of pulmonary metastatic tumors, TDT and DFI were examined, and the laterality, number of pulmonary metastatic tumors and DFI were considered to be useful prognostic factors. DFI among them was most closely associated with postoperative survival days. 3) A significant difference in the number of excised nodules was found between the DFI less than 90 days group and the DFI not less than 90 days group, and the number in the former group was significantly larger. 4) It was suggested that postoperative observation and close examination for pulmonary metastasis at about 3 months intervals after of primary focus are important, and also, positive or negative pulmonary metastasis as the time of examination, particularly, the number metastatic nodules of less than 5 or not less than 5, are reflected in the prognosis. 5) Expected survival time after the first operation pulmonary metastasis appeared possible to estimate as 3.0 x DFI days.

Adolescent↗

PubMed1998

A case of pulmonary metastases of synovial sarcoma surviving for a long period after active surgery.

The patient was a 24-year-old woman. She underwent marginal excision of synovial sarcoma originating in the right femoral soft tissue at the age of 18, followed by local radiation therapy and chemotherapy. At the age of 20, abnormal shadow was indicated in bilateral lungs on plain roentgenography of the chest, and she underwent open-chest surgery for excision of bilateral pulmonary metastatic tumors. She was subjected to bilateral thoracotony repeatedly thereafter for a total of 5 times, and all of the metastatic foci detected in each operation were resected. Consequently, she has been surviving for a long period of about 7 years. The therapeutic outcome of tumor of bone soft tissue is greatly affected by its pulmonary metastasis. Although the therapeutic outcome has recently been improved by large dose chemotherapy and active excision of metastatic foci in the lung, survival time in the case of synovial sarcoma, giant cell sarcoma and Ewing's sarcoma is not very long yet. In the present study, we observed a patient who had lung metastasis of synovial sarcoma of which prognosis is generally considered poor has been surviving for a long time of 7 years owing to active excision of pulmonary metastatic foci. The relation of the present prognostic factors to those in the past were compared.

Adult↗

PubMed1998

[Relative valve area stenosis after replacement of a Starr-Edwards mitral valve (model 6520) for corrected TGA (S, L, L): report of a case].

The patient was a 38-year-old man who had undergone mitral valve replacement with a Starr-Edwards disc valve (model 6520, 3 M, phi 30 mm, functional valve area: 2.85 cm2) at the age of 15 years for TR combined with corrected TGA. He developed dyspnea on exertion and palpitations at the age of 30 years, and paroxysmal supraventricular tachycardia appeared at the age of 35 years. Cardiac catheterization revealed that the PCWP was 30 mmHg and the TVA was 1.1 cm2, and a diagnosis of stenosis of the prosthetic valve was made. Thus, replacement of the Starr-Edwards disc valve using a BICARBON double leaflet valve (phi 27 mm, functional valve area: 2.85 cm2) was performed. The operative findings of the Starr-Edwards disc valve revealed a normal appearance and no pannus growth. Postoperative echocardiography and cardiac catheterization found that the TVA was 3.7 cm2 and the PCWP was 13 mmHg. The actual valve area of the disc valve sewn on the ventrical, which was anatomically RV construction might have been smaller than the ideal area; however, the double leaflet valve proved efficient in our patient. This case report serves to demonstrate that because of the postoperative difference in measurement between the actual valve area and the prostheticin ball or disc valve, patients undergoing mitral valve replacement must be followed up carefully.

Adult↗

PubMed1997

Essential light chain exchange in smooth muscle myosin.

The exchange of 17-kDa essential light chain (LC17) in smooth muscle myosin was carried out by incubating myosin with a 10-fold molar excess of exogenously added LC17 over the corresponding endogenous light chain in the presence of trifluoperazine and 4.5 m ammonium chloride. Porcine aorta myosin contains two kinds of LC17 isoform, LC17nm and LC17gi, while chicken gizzard myosin contains only one kind of LC17 isoform. As LC17gi can be separated from LC17nm and gizzard LC17 by urea-gel electrophoresis, LC17nm in aorta myosin and LC17 in gizzard myosin were exchanged with LC17gi and LC17gi in aorta myosin was exchanged with LC17nm, and the degree of exchange was estimated by urea-gel electrophoresis. Under the optimal conditions (6 and 10 degrees C for aorta and gizzard myosin, respectively), nearly 90% of exchange, which is close to the theoretical value, was achieved for the former combinations, and a slightly lower exchange was obtained for the latter. The LC17-exchanged myosins contained stoichiometric amounts of the heavy and light chains and retained the original nature in the phosphorylation-dependent actin-activated ATPase activity, 6S-10S conformational transition, and filament assembly.

Actin Cytoskeleton↗

PubMed1997

A Case of Apocrine Carcinoma of the Breast Presenting as Two Cysts.

A case of apocrine carcinoma of the breast presenting as two cysts is reported. A 60-year-old woman had two soft, mobile, well-defined masses measuring 4 x 2.5 cm and 1.5 x2.5 cm in diameter in the lower-inner quadrant of the right breast. Tumor markers such as CEA, CA15-3, BCA225 and NCC-ST-439 were within normal limits. Mammography showed two oval radioopaque masses with microcalcificatin in the smaller one. Ultrasonography disclosed two cysts and papillary projection in the larger one. Fine needle aspiration cytology revealed apocrine carcinoma of the breast. Excisional biopsy confirmed the diagnosis of apocrine carcinoma with focal invasion. Modified radical mastectomy was performed. Pathological study showed that the tumor mainly proliferated in the cysts and the two cysts communicated with each other through an involved duct. There was no apocrine metaplasia in adjacent mammary gland. There were no metastatic lymph nodes. This case may be regarded as intraductal apocrine carcinoma developing two cysts with focal invasion.

Journal Article↗

PubMed1997

In vivo intravascular laser photodynamic therapy in rabbit atherosclerotic lesions using a lateral direction fiber.

BACKGROUND AND OBJECTIVE: This study was performed to evaluate the possibility of inducing regression of atherosclerotic foci by photodynamic therapy (PDT) using hematoporphyrin derivative (HpD). STUDY DESIGN/MATERIALS AND METHODS: Atherosclerotic rabbits were divided into four groups: A (n = 6) and C (n = 6) were given 5 mg/kg of HpD intravenously; Groups B (n = 4) and D (n = 4) were not. Twenty-four hours after HpD administration, the aortae of groups A and B were exposed to 200 mw output argon dye laser beam at 630 nm for 10 minutes; groups C and D were exposed to 400 mw for 5 minutes. Three rabbits from groups A and C and two rabbits from groups B and D were sacrificed immediately after laser photoradiation, being named groups A 0, C 0 and groups B 0, D 0, respectively. Groups A 7, C 7, and Groups B 7, D 7 were sacrificed 7 days after the photoradiation. RESULTS: In groups A 7 and C 7, most intimal cells and endothelial cells had become necrotic and disappeared, and a loss of intima was observed. No such changes were found in groups B 7, D 7. CONCLUSION: The above data suggest that PDT caused effective regression of the atherosclerotic lesions.

Animals↗

PubMed1997

Assessment of vasoreactivity in brain edema by acetazolamide activation SPECT and PET.

Our study was performed to find out cerebrovascular reactivity post acetazolamide administration in patients with peritumoral edema. Adult patients (n = 9) underwent CBF measurement by 99mTc-HMPAO SPECT pre and post 1 gram i.v. acetazolamide. In all patients, this procedure was repeated once again within 10 days of performing tumor removal. Five of these patients also underwent CBF measurement pre and post 1 gram i.v. acetazolamide post surgery only using oxygen-15 labeled H2O PET. Asymmetry index (AI) was calculated as ratio of ROI counts in the peritumoral edematous area and symmetrical ROI on the contralateral normal hemisphere. The AI increased after acetazolamide in edematous gray matter post operatively though the resting AI remained almost same post operatively. AI in edematous white matter showed non-significant increase post operatively both at rest and after acetazolamide. Good linear correlation of AI between PET and SPECT was observed both in gray and white matter. The improvement of vascular reactivity in edematous gray matter after tumor removal suggests that mass effect not only reduces CBF but also suppresses vascular reactivity. White matter vascular reactivity in early post operative period is little improved, possibly due to factors other than mass effect i.e. excess water accumulation in white matter perivascular space.

Acetazolamide↗