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Biomedical subjects

A Shimizu

Publications and source records attributed to A Shimizu.

At least 307 records · Page 17Linked to original sources
PubMed1994

Incidence and electrophysiologic characteristics of supernormal atrial conduction in humans.

The incidence and electrophysiologic characteristics of supernormal atrial conduction (SNC) were examined by cardiac stimulation in 53 control subjects. Their ages ranged from 15 to 71 years (mean age, 50 +/- 21 years) (mean +/- SD). There were 27 women and 26 men in the study. Conduction of premature atrial responses from the sinus node to the atrioventricular node (intraatrial conduction time) was supernormal in 27 (51%) subjects and conduction to the left atrium (interatrial conduction time) was supernormal in 35 (66%) subjects (difference not significant). At coupling intervals ranging between 440 and 240 ms, the conduction time of the premature beats was as much as 25 ms shorter than that of the basic driven beats. The maximum decrease in interatrial conduction time during the period of SNC was 13 +/- 5 ms and the maximum decrease in intraatrial conduction time was 9 +/- 3 ms (P < .001). The supernormal interatrial conduction zone was 71 +/- 29 ms and the supernormal intraatrial conduction zone was 57 +/- 25 ms (P < .05). There was a significant positive correlation between the SNC zone and the maximum decrease in conduction time (r = .82; P < .001). Supernormal atrial conduction was stable, reproducible, and remained constant in individual patients. Supernormal atrial conduction was found to be a relatively frequent phenomenon. There was a significantly greater SNC zone and maximum decrease in conduction time in interartrial conduction than in intraatrial conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function↗
PubMed1994

Repetitive atrial firing and fragmented atrial activity elicited by extrastimuli in the sick sinus syndrome with and without abnormal atrial electrograms.

Endocardial catheter mapping of the right atrium during sinus rhythm and programmed atrial stimulation were performed in 50 patients with sick sinus syndrome to investigate the relationship between abnormal atrial electrograms recorded during sinus rhythm and some determinants of the atrial vulnerability such as repetitive atrial firing and fragmented atrial activity elicited by single extrastimulus. The patients were divided into 2 groups on the basis of the presence (Group I) or absence (Group II) of abnormal atrial electrograms recorded during sinus rhythm. In Group I (N = 32), repetitive atrial firing was induced in 23 (72%) patients, and in Group II (N = 18) in 6 (33%) patients; p less than 0.01. The repetitive atrial firing zone was 41 +/- 37 ms in Group I and 12 +/- 18 ms in Group II; p less than 0.001. Fragmented atrial activity was induced in 30 (94%) patients from Group I, and in 8 (44%) patients from Group II; p less than 0.0001. The fragmented atrial activity zone was 47 +/- 42 ms in Group I and 14 +/- 19 ms in Group II; p less than 0.0001. The atrial electrogram width at the premature beat (A2; p < 0.02) and the maximum A2/A1 ratio (p < 0.002) were 178 +/- 53 ms and 196% +/- 40%, respectively in Group I, and 141 +/- 36 ms and 159% +/- 30%, respectively in Group II. Atrial fibrillation was induced in 13 (41%) patients from Group I, and in 1 (6%) patient from Group II (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Role of increased DNA synthesis activity of hepatocytes in multicentric hepatocarcinogenesis in residual liver of hepatectomized cirrhotic patients with hepatocellular carcinoma.

To examine whether the marked increase in DNA synthesis of hepatocytes in cirrhotic liver might elicit multicentric hepatocarcinogenesis, we examined the relationship between new development of hepatocellular carcinoma (HCC) and the bromodeoxyuridine (BrdU) labeling index (LI) of hepatocytes in the residual liver of hepatectomized patients with liver cirrhosis (LC) and HCC. Eighteen hepatectomized patients with LC and HCC, whose resected liver revealed neither portal nor hepatic vein invasion by histologic examination, were studied (to exclude cases with intrahepatic metastasis). DNA synthesis activity of hepatocytes from the residual cirrhotic liver was measured by a BrdU/anti-BrdU in vitro method. The incidence of HCC recurrence was studied during a 3-year follow-up period. Among 18 patients, 9 patients had recurrence and 9 did not. The average BrdU LI in the recurrent patients was 2.6 +/- 1.3% and was significantly higher than that in patients without recurrence (1.4 +/- 0.5%, P < 0.05). All five patients who had a BrdU LI of 2.4% or above showed recurrence within 3 years, as compared with 4 of 13 (30.8%) patients with BrdU LI of less than 2.4% (P < 0.05). Our data indicate that abnormally high DNA synthesis in hepatocytes in the background cirrhosis might lead to the development of multicentric carcinogenesis in human cirrhotic liver, and in the residual cirrhotic liver of hepatectomized patients with HCC and LC, it may be a predictor of new development of HCC.

Adult↗
PubMed1994

A new type of staphylococcal exfoliative toxin from a Staphylococcus aureus strain isolated from a horse with phlegmon.

A new type of staphylococcal exfoliative toxin (sET) was isolated from the culture filtrate of a Staphylococcus aureus strain isolated from a horse with skin infection including phlegmon. The new sET was purified by precipitation with 80% saturated ammonium sulfate, column chromatography on DEAE-cellulofine A-500, gel filtration on a Sephadex G-75 column, and polyacrylamide gel electrophoresis (7.5% polyacrylamide). The new sET elicited general exfoliation of the epidermis with the so-called Nikolsky sign when inoculated into both 3-day-old mice and 1-day-old chicks, whereas sETA and sETB from human strains of S. aureus caused exfoliation in a 3-day-old mouse alone and shET from a porcine strain of Staphylococcus hyicus caused exfoliation in 1-day-old chicks alone. Intraepidermal splitting was observed at the granular layer of the epidermis of mice inoculated with the new sET as well as those inoculated with sETA. Exfoliation at the germinative layer of the epidermis was also observed in the chicks inoculated with the new sET as well as those inoculated with shET. The new sET was serologically different from sETA, sETB, and shET and showed the same molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was thermolabile and lost its toxicity after being heated at 60 degrees C for 15 min. We propose that the new sET be designated as sETC.

Animals↗
PubMed1994

Mechanism of interruption of atrial flutter by moricizine. Electrophysiological and multiplexing studies in the canine sterile pericarditis model of atrial flutter.

BACKGROUND: Moricizine is said to have potent effects on cardiac conduction but little or no effect on cardiac refractoriness. METHODS AND RESULTS: The effects of moricizine (2 mg/kg IV) on induced atrial flutter were studied 2 to 4 days after the creation of sterile pericarditis in 11 dogs. Ten episodes of stable atrial flutter before and after the administration of moricizine were studied in 9 dogs in the conscious, nonsedated state, and 7 episodes were studied in 6 dogs in the anesthetized, open chest state. In the conscious state, the effects of moricizine on atrial excitability, atrial effective refractory period, and intra-atrial conduction times were studied by recording during overdrive pacing of sinus rhythm from epicardial electrodes placed at selected atrial sites. Moricizine prolonged the atrial flutter cycle length in all the episodes, from a mean of 133 +/- 9 to 172 +/- 27 milliseconds (P < .001), and then terminated 7 of the 10 episodes. Moricizine increased the atrial threshold of excitability from a mean of 2.3 +/- 1.4 to 3.3 +/- 2.2 mA (P < .01) and prolonged intra-atrial conduction times (measured from the sulcus terminalis to the posteroinferior left atrium) from a mean of 58 +/- 6 to 64 +/- 5 milliseconds (P < .005). Prolongation of the atrial effective refractory period from 166 +/- 20 to 174 +/- 24 milliseconds (P < .05) was observed only at the sulcus terminalis site. In the open chest studies, administration of moricizine prolonged the atrial flutter cycle length from a mean of 150 +/- 15 to 216 +/- 30 milliseconds (P < .001) and then terminated the atrial flutter in all 7 episodes. As demonstrated by simultaneous multisite mapping from 95 bipolar sites on the right atrial free wall, the atrial flutter cycle length prolongation was either due to further slowing of conduction in an area of slow conduction in the reentrant circuit of the atrial flutter (5 episodes) or further slowing of conduction in an area of slow conduction plus the development of a second area of slow conduction (2 episodes). The change in conduction times in the rest of the reentrant circuit was negligible (10.9 +/- 8.7% of the total change). In all 7 episodes, the last circulating reentrant wave front blocked in an area of slow conduction. CONCLUSIONS: Moricizine (1) prolongs the atrial flutter cycle length, primarily by slowing conduction in an area of slow conduction in the reentrant circuit, (2) terminates atrial flutter by causing block of the circulating reentrant wave front in an area of slow conduction of the reentrant circuit, and (3) effectively interrupts otherwise stable atrial flutter in this canine model. The reason for these effects of moricizine are not readily explained by its effects on global atrial conduction times and refractoriness studied during sinus rhythm. Local changes in conduction in an area(s) of slow conduction are responsible for both cycle length prolongation and atrial flutter termination rather than the traditional wavelength concept of head-tail interaction.

Animals↗
PubMed1994

Effects of 2,5-dimethylpyrazine on plasma testosterone and polyamines- and acid phosphatase-levels in the rat prostate.

The effects of 2,5-dimethylpyrazine (DMP) on plasma testosterone and levels of polyamines and acid phosphatase in the prostate of rat were studied. A high dose of DMP administered once daily for two weeks to juvenile male rats significantly decreased plasma testosterone and levels of polyamines and acid phosphatase in the prostate. These effects were not obtained by administration to mature male rats, and the inhibition was thus recognized to occur during the growth period. These findings suggest that a high dose of DMP inhibits the biosynthesis of polyamines and acid phosphatase in the prostate by decreasing the circulating testosterone level.

Acid Phosphatase↗
PubMed1994

Effects of intravenous verapamil on atrial vulnerability.

To investigate the effects of verapamil on indicators of atrial vulnerability, we examined 30 patients with paroxysmal supraventricular tachycardia who received intravenous verapamil during an electrophysiologic study. Single atrial extrastimuli were given before and after intravenous administration of verapamil to induce repetitive atrial firing (RAF) or atrial fibrillation, and to examine the maximum A2/A1, which was defined as the maximum ratio of the duration of the atrial electrogram resulting from premature stimulation (A2) to that resulting from the basic drive beat (A1). The maximum A2/A1 increased from 145 +/- 20% to 154 +/- 25% (p < 0.02) after verapamil administration. The maximum A2/A1 in patients in whom neither RAF nor atrial fibrillation were induced both before and after verapamil were smaller than those in patients in whom RAF was induced only after verapamil (before; 138 +/- 20% vs 165 +/- 15%, p < 0.02. after; 144 +/- 22% vs 172 +/- 17%, p < 0.05). RAF or atrial fibrillation was induced only after verapamil in 6 patients, who showed a maximum A2/A1 before verapamil of 150% or more. These data suggest that verapamil may induce repetitive atrial firing and possibly atrial fibrillation in some predisposed patients, especially in those that have a greater maximum A2/A1, which may be an indicator of local intraatrial conduction delay before drug infusion.

Adolescent↗
PubMed1994

[Werner's syndrome associated with meningioma and a cerebrovascular disorder].

We present a case of Werner's syndrome associated with intracranial meningioma and a cerebrovascular disorder. A 49-year-old male was transferred to this hospital with a head injury as a result of a car accident, and a CT scan revealed a traumatic intracerebral hemorrhage. The patient displayed the characteristic clinical features of Werner's syndrome, including premature senility, juvenile cataract, atrophic skin, and a tendency to ward familial occurrence was present. MRI and cerebral angiography revealed multiple intracerebral hemorrhages, perhaps due to amyloid angiopathy, multiple lacunar infarctions and parasagittal meningioma. This is the first report on the MRI findings in the brain of a patient with Werner's syndrome. We suspect that of Werner's syndrome also shows evidence of premature aging on MR images.

Cerebral Angiography↗
PubMed1994

[A case report: ovarian carcinoma IVth can become complete remission by immunochemotherapy].

A patient with navel metastasis from ovarian carcinoma was treated by immunotherapy and neo-adjuvant intraarterial infusion chemotherapy (OK-432 i.c., VP-16 25 mg/body x 10 days po, CDDP 100 mg/m2 iA, CPM 200 mg x 3 days/body i.v., THP 50 mg/m2 iA). Maximal blood concentration of THP was 1.081 micrograms/ml at 1 hour intraarterially and 0.091 microgram/ml at 2 hour intravenously. THP concentration of arteria is ten times higher than that of venous. And the area under the curve (AUC) of THP is 3.46 micrograms/ml/hr intraarterially and 0.43 microgram/ml/hr at intravenous. Two courses of the neo-adjuvant intraarterial chemotherapy were done. One month after, the first operation was performed. Each tissue platina concentration is 9.72 micrograms/ml is 9.72 micrograms/cm3 uterus cervix, 7.10 micrograms/cm3 uterus corporis, 5.72 micrograms/cm3 left ovarium, 2.64 micrograms/cm3 right ovarium, 0.52 microgram/cm3 paraaortic lymph node. After the immuno-chemotherapy, the metastatic tumor appeared remarkably smaller and the main tumor regained normal size and we achieved the optimal operation successfully. This patient was treated with double platina chemotherapy by intraperitoneal infusion using implantable reservoir access after the first operation (VP-16 200 mg/m2 i.p. D1, CDDP 100 mg/m2 ip D1, CBDCA 300 mg/m2 i.v. D3). This patient can keep the state of cytological complete remission for more than four months after the second look operation. Now she continues maintenance immuno-chemotherapy from a home doctor.

Adenocarcinoma↗
PubMed1994

[Age-related alteration of tear dynamics in normal volunteers].

Age-related alteration of tear dynamics was studied using a newly developed fluorophotometer. The subjects, 55 eyes of 30 normal volunteers, included 32 eyes of 16 younger subjects in their twenties and 23 eyes of 14 older subjects aged 50 years and above. After instillation of 1 microliter of fluorescein solution at a concentration of 50 micrograms/ml into the temporal bulbar conjunctiva, fluorescence intensity was measured with the fluorophotometer every minute for 10 minutes after instillation. Fluorescein concentration was calculated from the intensity, and various parameters of tear dynamics were analyzed. In the younger subjects, the tear volume, initial turnover rate and basal turnover rate were 10.6 +/- 6.0 microliters, 37. 1 +/- 15.6%/min, and 25.8 +/- 15.2%/min, respectively. In the older subjects, these values were 6.5 +/- 2.6 microliters, 26.5 +/- 11.4%/min, and 20.5 +/- 13.5%/min, respectively. The basic tear flow rate, calculated from the basal turnover rate and tear volume, was 2.7 +/- 2.2 microliters/min in the younger and 1.4 +/- 1.0 microliter/min in the older subjects. There was a statistically significant difference in the tear volume, tear turnover rate, and basic tear flow rate between the younger and older subjects.

Adult↗
PubMed1994

[p53 expression in colorectal adenoma and early carcinoma].

Expression of p53 was studied immunohistologically in 25 adenomas, 46 cancers in adenoma, and 18 cancers without adenoma, which were obtained by endoscopic polypectomy or mucosal resection. Positive ratio of p53 expression was 100% in cancer without adenoma, 78.3% in cancer in adenoma, and 48% in adenoma. We divided the positive case of p53 expression to three staining patterns, poorly stained type, focal type and diffuse type. The diffuse type was most of cancer without adenoma. In each diagnostic group there was no significant colleration between sex, age, and shape of polyp and the staining pattern. But in cancer without adenoma, there was significant colleration between size of polyp and the staining pattern, and number of the diffuse type increased as the polyp size was larger. Consequently, it was suggested that p53 takes a role of cancerization from adenomas at every step.

Adenoma↗
PubMed1994

[The influence of ulinastatin on renal function during anesthesia for renal transplantation].

The purpose of this study was to evaluate the influence of ulinastatin (UST) on renal function and changes in granulocyte elastase during anesthesia in 10 living related and 10 cadaveric renal transplantations. UST (300,000 units) was administered after the induction of anesthesia and renal vessel anastomosis, respectively. The living patients who received UST had greater urine volume during the operative and postoperative periods. In addition, the granulocyte elastase values of these patients showed relative suppressive changes during the intraoperative and postoperative periods. In cadaveric renal transplant patients, UST did not influence serum BUN or creatinine, although urine volume was greater in the UST-treated patients than in the patients who did not receive. We could not conclude that the intraoperative administration of UST affected the renal function of renal transplants, but we did find that UST is useful to suppress granulocyte elastase which is concerned with the index of stress or inflammation. It is necessary to investigate further the method of administration of UST for renal transplantation.

Adult↗
PubMed1994

Successful heterotransplantation of human endometrium in SCID mice.

OBJECTIVE: To establish an experimental system useful for long-term evaluation of human endometrial tissue by its heterotransplantation to SCID mice. METHODS: Human endometrium was transplanted subcutaneously into SCID mice, nude mice, or nude mice given anti-asialo GM1 antibody, a natural killer activity suppressor. The transplant was observed by ultrasonography for up to 10 weeks and then morphologically. To assess the drug susceptibility of the transplant, danazol (10-100 mg/kg/day orally), buserelin (0.01 mg/kg/day subcutaneously), or estradiol (0.5 mg/kg/day intraperitoneally) was administered to the host mice for up to 10 weeks after the transplantation. Multiple-comparison procedures were used for statistical evaluation. RESULTS: The heterotransplant was accepted 100% in SCID mice and natural killer activity-suppressed nude mice, but was significantly inferior (40%) in nude mice at 10 weeks after the transplantation. The transplant size was volumetrically measurable noninvasively by ultrasonography. Using this SCID mouse model, we could evaluate drug effects on the transplanted endometrium. CONCLUSION: This system in SCID mice may be useful for evaluating drug actions on human endometrium and endometriotic tissues.

Adult↗
PubMed1993

Unfolding of the molten globule state of alpha-lactalbumin studied by 1H NMR.

The urea-induced unfolding of the molten globule state of bovine alpha-lactalbumin was investigated by 1H nuclear magnetic resonance. In the molten globule state, most of the aromatic resonances deviate from their random coil values, indicating that aromatic side chains form some ordered structures in the molten globule state. When the urea concentration increases, the resonances are shifted, and the deviations from the random coil values are diminished. Because the chemical shifts of several random coil peptides are found to be independent of urea concentration, the urea-induced shifts of the resonances in the molten globule state reflect the unfolding transition of some ordered structures. The unfolding transitions measured by individual aromatic resonances do not coincide with each other. The unfolding transition curves obtained from some aromatic resonances are also different from those of the secondary structures measured by circular dichroism spectra. These results clearly show that the unfolding of the molten globule state of alpha-lactalbumin is not a cooperative two-state process.

Animals↗