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Biomedical subjects

A Shimizu

Publications and source records attributed to A Shimizu.

At least 343 records · Page 19Linked to original sources
PubMed1993

Electrophysiologic effects of a new class III antiarrhythmic agent, E-4031, on atrial flutter, atrial refractoriness, and conduction delay in a canine sterile pericarditis model.

Numerous studies have shown that E-4031 generally prolongs the atrial effective refractory period (AERP) without affecting cardiac conduction. The effects of E-4031 on AERP and cardiac conduction at short cycle lengths (CLs) close to the AERP were measured in 12 dogs with sterile pericarditis. Three pairs of electrodes were sutured at three sites in the atria 4 days after the model was created. We measured AERP and maximum conduction delay (MCD) after 8 beats train at CLs of 400, 300, 200 and 150 ms before and during continuous infusion of E-4031 (0.1 microgram/kg/min) that followed an initial dose of 10 micrograms/kg/min/5 min. E-4031 interrupted sustained atrial flutter (AF) (> or = 10 min) in 4 of 5 episodes and atrial fibrillation (> or = 10 min) in 4 of 4. The CL of AF defined as a rapid atrial rhythm (rate > or = 240 beats/min) in five episodes studied in the sterile pericarditis model was significantly (p < 0.005) prolonged from 120 +/- 8 to 160 +/- 17 ms. There were significant (p < 0.005) increases in AERP at each CL, and prolongation of AERP was 39 +/- 18, 31 +/- 14, 23 +/- 14, and 16 +/- 14 ms at CL 400, 300, 200, and 150 ms, respectively. E-4031 produced less prolongation of AERP at short pacing CLs and had no effect on conduction time during atrial rapid pacing at CLs > 150 ms. E-4031 did not prolong MCD at CL 400 ms, but did prolong MCD at CLs of 300, 200, and 150 ms, despite prolongation of AERP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Relationship between atrial conduction defects and fractionated atrial endocardial electrograms in patients with sick sinus syndrome.

The relationship between abnormal atrial electrograms (AAE) recorded during sinus rhythm by endocardial catheter mapping of the right atrium and the atrial conduction defects of sinus impulses or single atrial extrastimuli was investigated in 44 patients with sick sinus syndrome. The patients were divided into two groups on the basis of the presence (n = 29) or absence (n = 15) of AAE recorded during sinus rhythm. The P wave duration in the AAE (+) Group patients was 137 +/- 14 msec, and 125 +/- 15 msec in the AAE (-) Group; P < 0.02. The intraatrial conduction time of sinus impulses in the AAE (+) Group was 54 +/- 12 msec, and 39 +/- 9 msec in the AAE (-) Group; P < 0.001. The interatrial conduction time in the AAE (+) Group was 101 +/- 14 msec, and 78 +/- 16 msec in the AAE (-) Group; P < 0.001. In the AAE (+) Group, 11 (38%) patients had a sinus node recovery time > 4 seconds, whereas in the AAE (-) Group there was only one (6%) patient; P < 0.03. AAE showed a specificity of 93% and a positive predictive accuracy of 91% in predicting inducibility of atrial fibrillation. The sensitivity was 35% and the negative predictive accuracy was 42%. Sustained atrial fibrillation was induced in ten (35%) patients of the AAE (+) Group, and in one (7%) patient of the AAE (-) Group; P < 0.05. These data suggest that in patients with sick sinus syndrome who possess abnormal endocardial electrograms in sinus rhythm within the right atrium have: (1) a significantly longer P wave duration; (2) a significantly longer intraatrial and interatrial conduction time of sinus impulses; and (3) a significantly greater sinus node dysfunction and higher incidence of induction of sustained atrial fibrillation. It is concluded that there are significantly greater atrial conduction defects in patients with sick sinus syndrome who possess AAE within the right atrium during sinus rhythm.

Adult↗
PubMed1993

Double response of the ventricle during transient entrainment in a common atrioventricular nodal reentrant tachycardia.

We report a patient with slow-fast atrioventricular (AV) nodal reentrant tachycardia, in which double ventricular response was demonstrated during rapid pacing at cycle length of 300 msec or less from the high right atrium. The determinants of double ventricular response during transient entrainment in the present case were: (1) a crucial conduction delay in the slow pathway; (2) the collision between the activation via the antegrade fast pathway (antidromically) of the last paced beat and the activation via the antegrade slow pathway (orthodromically) of the previous paced beat, instead of the unidirectional block in the slow pathway; and (3) the enhanced AV nodal conduction over the antegrade fast pathway.

Adult↗
PubMed1993

The association between hepatitis C virus infection and in vitro activation of the complement system.

The phenomenon of in vitro activation of the classical complement pathway at low temperatures (4-21 degrees C) is known as cold activation, and has been suggested to be associated with non-A, non-B hepatitis. We re-examined the association by using newly developed markers of hepatitis C virus (HCV) infection. Twenty-one cases randomly selected from those fulfilling the screening criteria of complement cold activation all showed evidence of HCV infection. More than half of 55 HCV antibody-positive cases selected randomly from our laboratory samples showed a tendency towards cold activation, whereas none of the HCV antibody-negative sera showed cold activation. All the HCV antibody-positive cases were negative in cold activation when CH50 was assayed with plasma. These results, taken together, indicate that cold activation of the complement system is strongly associated with HCV infection.

Cold Temperature↗
PubMed1993

Effects of dimethylpyrazine isomers on reproductive and accessory reproductive organs in male rats.

The effects of dimethylpyrazine isomers on reproductive and accessory reproductive organs in male rats were studied. Following the administration of 2,5-dimethylpyrazine (100 mg/kg, s.c.) the weight of prostate and seminal vesicles, as well as testosterone levels in plasma were significantly decreased. One isomer of dimethylpyrazine, 2,6-dimethylpyrazine (100 mg/kg, s.c.), affected only the seminal vesicles, while 2,3-dimethylpyrazine had no influence on accessory reproductive organs. Following administration of 100 mg/kg of 2,5-dimethylpyrazine, acid phosphatase activity in the prostate and fructose content in the seminal vesicles were also significantly decreased compared with tissues from vehicle-treated animals. Weight of the testes and acid phosphatase activity therein were not affected following the administration of 2,5-dimethylpyrazine, nor were numbers of spermatozoa in the epididymis. These results showed that 2,5-dimethylpyrazine induced decrease in prostate and seminal vesicle weight by inhibiting testosterone uptake and reducing plasma testosterone levels.

Acid Phosphatase↗
PubMed1993

[Fluorophotometric measurement of tear volume and tear turnover rate in human eyes].

Tear volume and turnover rate were measured in 31 normal eyes using a newly designed objective fluorophotometer. After instillation of 1 microliter of 50,000 ng/ml fluorescein solution, its concentration in the lower marginal strip was measured every minute for 10 minutes after instillation. The tear volume and the tear turnover rate were determined using the method of Mishima et al. (Invest. Ophthalmol. Vis. Sci., 1966). The tear volume in this study was 12.4 +/- 6.2 microliters, initial turnover rate was 31.5 +/- 14.4%/min., and basal turnover rate was 24.0 +/- 14.2%/min. (Mean +/- SD). There were no significant differences in sex, age or use of contact lens. We also measured the tear volume and turnover rate using 5 microliters of 10,000 ng/ml fluorescein solution in the same way. The result turned out to be significantly higher, suggesting that minimal irritation is required for evaluating the tear flow.

Adult↗
PubMed1993

[Tissue variability of androgen receptor gene in bulbospinal muscular atrophy--comparison of the number of CAG repeats between muscles and peripheral blood leukocytes].

We investigated an expansion of CAG repeats in exon 1 of androgen receptor gene in skeletal muscle tissue obtained from the patients with various neuro-muscular disorders (5 BSMA, 33 patients with amyotrophic lateral sclerosis, 3 patients with spinal progressive muscular atrophy and 2 patients with hereditary motor sensory neuropathy), by polymerase chain reaction (PCR) amplification according to LaSpadas' description. These muscle tissues had been stored at -70 degrees C freezer during 7 years. We also studied the tissue variation of CAG repeats size between muscles and peripheral blood leukocytes in 4 patients with BSMA. And we confirmed the increased number of CAG repeats in all 5 BSMA except for other patients with neurogenic muscular atrophy. In the 4 BSMA patients, we subcloned the PCR products from muscles tissues and peripheral blood leukocytes, and we determined the number of CAG repeats by sequencing. The repeats of them were 43-51, and all BSMA patients showed the same number of CAG repeats in muscles tissues and peripheral blood leukocytes. The CAG repeats fragment of BSMA may be stable region in frozen storage state for 7 years, and we didn't recognized the somatic variation at least between muscles tissues and peripheral blood leukocytes.

Adenosine↗
PubMed1993

[Perioperative psychological status of patients undergoing radical mastectomy and total hysterectomy].

Using four different psychological tests, namely Spielberger's rating scale [The State-Trait Anxiety Inventory (STAI)], Self-Rating Depression Scale (SDS), Maudsley Personality Inventory (MPI) and Baum test, we investigated the perioperative psychological status of patients undergoing radical mastectomy for breast cancer and compared data with those of patients undergoing total hysterectomy for uterine myoma. Parameters reflecting the psychological status of hysterectomy patients disclosed lower postoperative anxiety, and slight nervousness and persistent depression perioperatively. In contrast, in patients with breast cancer, those with nervousness had persistent anxiety and depression, while those without nervousness showed the same persistent depression as in hysterectomy patients, as well as a high anxiety level postoperatively. Therefore, we speculate that the persistence of depressive mood during the perioperative period is a factor in the psychological disturbance of mastectomy patients with breast cancer, and moreover, they appear markedly apprehensive because of cancer. These results suggest that the persistence of anxiety and depressive mood associated with cancer is a prime factor in the etiology of postoperative psychological disturbance.

Adult↗
PubMed1993

Studies on familial hypotransferrinemia: unique clinical course and molecular pathology.

Some unsolved problems--late onset of anemia and growth retardation (at age 7 years), healthy siblings showing very low transferrin (TF) level, and unexplained mode of inheritance--were found in family members of a congenital atransferrinemia already reported in 1972. The long-term clinical, laboratory, and developmental observations revealed that after 5 years of apo-TF supplementary therapy the patient's anemia gradually disappeared, and he started to grow again without further therapy. Immunoelectrophoretic study disclosed a severe deficiency of both TF and haptoglobin in the patient. The recovery from his anemia and the resumption of his physical development were dependent only on his TF level: that is, from a negligible level it increased to 10-20 mg/dl (normal, 205-370 mg/dl), a level similar to that of his TF-deficient siblings, who had been in good health since birth. The TF analysis of the patient and his family suggests that the minimum TF requisite in this family may be close to 10-20 mg/dl; subjects with more than 20 mg/dl are apparently healthy; with less than 10 mg/dl they may develop severe growth retardation and anemia, and extreme deficiency may be lethal. Also, coexisting haptoglobin deficiency might alleviate hemosiderosis. Further, the isoelectric focusing study disclosed that there was only a small amount of TF variant in these siblings including the patient. The study of the family confirmed that this variant was produced by an allelic gene derived from their father. So, the original diagnosis of congenital atransferrinemia should be revised as familial hypotransferrinemia transmitted with autosomal recessive mode, and the subjects with a recessive character may be compound heterozygotes of the "variant" allele and the "null" allele.

Adolescent↗
PubMed1993

[A study on medical examination items added to periodic health examination as a result of amendment of the Ordinance on Occupational Safety and Health].

In accordance with the recent amendment of the Ordinance on Occupational Safety and Health, anemia (Hb, RBC), liver function (GOT, GPT, gamma-GTP), serum lipid levels (T-Chol, TG) and ECG have become essential items of the general periodic health examination. Data on these items were examined on 86 employees on whom chest radiography, blood pressure, urinalysis and past history revealed no abnormalities in periodic health examination at their companies. The subjects were 58 males and 28 females, between 34 and 66 years old (47.6 years on average). Anemia was found in 3 (3.5%), liver dysfunction in 13 (15.1%), abnormal serum lipid levels in 24 (27.9%) and ECG abnormalities in 8 (9.3%). The new periodic health examination system is thus thought to be useful in the early detection and prevention of adult diseases. To enhance this utility, it appears important to instruct those found abnormal in any parameter to have extensive examination. In discussing liver function and serum lipid level abnormalities, obesity, drinking and food intake should be considered.

Adult↗
PubMed1993

[Ring eosinophils in patients with lowered eosinophil peroxidase activity].

Leucocyte cytograms were obtained by using a Technicon H6000 (Technicon Instrument Corporation, Tarrytown, NY, USA) in conjunction with an automated flow-cytochemical analyser by which leucocytes can be differentiated by cytochemical (peroxidase activity) and optical (cell size) methods. By analysis of cytograms obtained in this way, we found twelve cases of lowered eosinophil peroxidase activity among approximately 600,000 blood samples-days between 1984 and 1989. Ring eosinophils were observed on the peripheral blood smears in 2 out of 12 cases. The first case was a 41-year-old female confined to hospital with Hashimoto's disease, and the other a 54-year-old female hospitalized for trauma. In both cases, the percentage of eosinophils was normal, although some had ring-shaped nuclei with a large central nuclear hole and a nuclear ring formed with a thin nuclear chromatin bridge. Ring eosinophils previously have been described in patients with hematological malignancy, hypereosinophilic syndrome or severe alcoholism. Recently we observed ring eosinophils in a healthy individual for the first time. Although ring eosinophils may not have specific diagnostic significance, these cases are reported because they displayed a rare phenomenon.

Adolescent↗
PubMed1993

[A case of mesangioproliferative glomerulonephritis (GN) associated with unique lesions of juxtaglomerular apparatus (JGA) and interstitium].

A case of mesangioproliferative glomerulonephritis (GN) associated with unique lesions of the juxtaglomerular apparatus (JGA) and interstitium is discussed. A 31-year-old Japanese woman who developed eyelid and pretibial edema with nephrotic-range proteinuria (4.8 g/day) and without hematuria, was admitted. Her proteinuria and edema quickly disappeared within 7 days after admission without treatment. Her blood examinations revealed hypocomplementemia on admission, but complement recovered to normal levels after 4 weeks. A renal biopsy specimen obtained on the 5th day of admission revealed moderate mesangioproliferative GN with marked periarteriolar inflammatory cell infiltrations in the JGA and occasionally in the tubular interstitium. Depositions of IgG, IgA, IgM and C3 were observed in the glomerular mesangial regions and some capillary walls, but not in the extraglomerular areas. Titers of GN-related viral antigens were not increased. Although the renal histology of this case was similar to that of experimental acute cytomegalovirus (CMV) GN in mice (described by Smith, R.D.), we could not detect CMV antigen by indirect immunofluorescent method or the virus-like particles by electron microscopy. Clinical cases of nephropathy combining lesions of the glomerulus, JGA, and interstitium are very rare. We herein report a patient with mesangioproliferative GN, who underwent an acute clinical course associated with unique inflammatory lesions of the JGA and/or interstitium.

Adult↗
PubMed1993

[The growth activity and DNA ploidy in anaplastic carcinoma transplanted to nude mice].

Recently, nuclear DNA contents of various human tumors were studied, and DNA aneuploidy was thought to have prognostic significance in many kinds of malignant tumors. Although the same significance was reported in thyroid carcinoma, the anaplastic thyroid carcinoma which is one of the most aggressive tumor in human malignant neoplasms, not always shows DNA aneuploidy. Therefore, using 3 xenografts established from 3 patients with anaplastic thyroid carcinomas, we investigated their growth activity, DNA ploidy and chromosome abnormalities. Two of these xenografts grew relatively fast in nude mice showing diploid or near diploid state in a flow cytometric study, and also, showed many structural abnormalities in chromosome analysis by the G-banding technique. The remaining one xenograft showed slower growth and aneuploidy, and had extensive numerical but less structural variability in its chromosomal constitution. These results indicate that some tumors showed DNA diploidy and have structural chromosome abnormalities and also suggest that the prognostic value of quantitative DNA measurement is limited in such tumors.

Aneuploidy↗