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Biomedical subjects

N Hirata

Publications and source records attributed to N Hirata.

At least 19 recordsLinked to original sources
PubMed1995

[Fine needle aspiration cytology in screening of prostatic cancer].

Between October 1990 and June 1993, 112 patients underwent fine needle aspiration cytology and core needle biopsy of the prostate under transrectal ultrasonographic guidance. They were suspected of having prostatic cancer from the prostatic antigen level, digital rectal examination and/or transrectal ultrasonography. Twenty seven of the 112 cases (24%) were diagnosed with prostatic cancer. Their cytological diagnoses showed 22 class IV or V, 2 class III, and 3 class I or II. Efficiency, false negative rate and false positive rate were 86%, 11% and 0% in fine needle aspiration cytology. We could obtain sufficient samples for fine needle aspiration cytology in all cases. No severe complication was observed. However, we missed 3 patients, in fine needle aspiration cytology, who were strongly suspected of having prostatic cancer, and reexamination or additional core needle biopsy would have been necessary on 15 of the 112 patients (13%) who showed false negative or class III cytological results, if we had screened prostatic cancer only by fine needle aspiration cytology. In conclusion, fine needle aspiration cytology may not be as useful as core needle biopsy to screen prostatic cancer.

Adenocarcinoma↗
PubMed1994

Response of right ventricular systolic function to exercise stress: effects of pulmonary vascular resistance on right ventricular systolic function.

To elucidate factors influencing responses of right ventricular systolic function to exercise stress, we evaluated the right ventricular ejection fraction and peak ejection rate with two different loading conditions, atrial septal defect and mitral stenosis, at rest and during exercise by means of gated equilibrium blood pool radionuclide ventriculography. In both atrial septal defect and mitral stenosis, strong correlations between changes in the right ventricular ejection fraction with exercise and pulmonary vascular resistance at rest (r = -0.97, p < 0.001; r = -0.86, p < 0.005: respectively) were found. Significant correlations between changes in the right ventricular peak ejection rate with exercise and pulmonary vascular resistance at rest (r = -0.85, p < 0.05; r = -0.75, p < 0.01: respectively) were found in atrial septal defect and mitral stenosis. Both the right ventricular ejection fraction and peak ejection rate were lower during exercise than at rest when pulmonary vascular resistance at rest was more than 200 dynes.sec.cm-5.m2 in both atrial septal defect and mitral stenosis. In conclusion, right ventricular systolic function responding to exercise stress was influenced by the pulmonary vascular resistance in both atrial septal defect and mitral stenosis.

Adult↗
PubMed1994

Synthetic studies of sesquiterpenes with a cis-fused decalin system, 5. A synthetic approach to the study of structure-activity relationships of the termiticidal norsesquiterpenoids, chamaecynone and related compounds.

Various analogues of chamaecynone [1] were prepared from alpha-santonin, and the termiticidal activity of these compounds was examined. All compounds possessing a 5 beta H-13-noreudesmane skeleton with a ethynyl group at C-7 showed significant termiticidal activity. Changes in the structure of the A-ring of these compounds also influenced the potency of their termiticidal activity.

Animals↗
PubMed1994

Alendronate modulates osteogenesis of human osteoblastic cells in vitro.

The bisphosphonates, which are carbon-substituted pyrophosphates, have been studied extensively both in vivo and in vitro to elucidate their effects on bone tissues and cells. However, because these agents were shown to have a potent inhibitory effect on bone resorption, the majority of studies have focused on only this aspect of bone metabolism. There appears to be less information regarding the direct effect of bisphosphonates on bone formation, so thus we undertook experiments to investigate the effects of bisphosphonates, especially alendronate, on the mineralization and matrix protein synthesis of human osteoblastic cells in vitro. The data show that the bisphosphonates, alendronate, etidronate and pamidronate, suppressed 1,25-dihydroxycholecalciferol (1,25(OH)2D3)-stimulated mineralization of human osteoblastic cells at high concentrations, while relatively lower concentrations of alendronate and etidronate potentiated mineralization of the cells in the presence of 1,25(OH)2D3. The potentiation of mineralization with alendronate was accompanied by increased synthesis of bone matrix proteins, osteocalcin and collagen, and the mRNA of pro alpha(I) collagen. These findings show that in addition to their well-known effects on bone resorption, bisphosphonates have significant and direct effects on osteogenesis in osteoblasts in vitro. The actual mechanism remains to be further investigated.

Alendronate↗
PubMed1994

Crossed and uncrossed segmental synaptic effects on obliquus externus abdominis motoneurons from cutaneous and cutaneous-muscle nerve in spinal cats and alpha-chloralose-anesthetized cats.

Segmental synaptic responses in the obliquus externus abdominis (OEA) for stimulation of the dorsal cutaneous and cutaneous-muscle (CD) nerve and the ventral cutaneous and cutaneous-muscle (CV) nerve were investigated in 49 spinal cats and 28 cats under alpha-chloralose anesthesia (chloralose cats) with an intracellular recording method. The result that there was no monosynaptic PSP in OEA motoneurons for stimulation of the CD or CV nerves (containing the cutaneous-muscle nerve) indicates that the cutaneous muscle of the dorsal or ventral area does not connect monosynaptically to the OEA motoneuron. The OEA motoneurons in chloralose cats received few effects from descending pathways coming from the upper spinal cord and the brain. Almost all OEA neurons had polysynaptic EPSP responses for stimulation of the ipsilateral or contralateral CD or CV nerves at 5-10T stimulus intensity in spinal or chloralose cats, which indicates that the OEA muscle can contract bilaterally when strong impulses of superficial afferents from the left or right skin or cutaneous muscle enter in the spinal cord.

Anesthesia, General↗
PubMed1994

Evaluation of regional myocardial perfusion in areas of old myocardial infarction after revascularization by means of intraoperative myocardial contrast echocardiography.

Because myocardial revascularization to areas of old myocardial infarction brings about functional recovery to some extent to myocytes in those areas, the assessment of regional myocardial perfusion on those areas after myocardial revascularization may allow myocardial viability to be estimated. Using intraoperative myocardial contrast echocardiography by direct injection of 2 ml sonicated 5% human albumin into saphenous vein grafts, we assessed regional myocardial perfusion in 16 revascularized areas of old myocardial infarction. We estimated the myocardial viability of areas with respect to myocardial perfusion, and we compared these results to both the improvement of regional wall motion after myocardial revascularization (increase in segmental wall thickening during systole) and relative thallium 201 activity obtained by quantitative analysis of preoperative exercise myocardial thallium 201 distribution on delayed images. The background-subtracted peak peak intensity of myocardial enhancement and the ratio of endocardial to epicardial intensity were determined in each revascularized area. An inverse correlation existed between peak intensity (18 +/- 7) and the endocardial/epicardial ratio (0.88 +/- 0.17) (r = -0.63, p < 0.01). A good correlation was found between peak intensity and both the percent increase in segmental wall thickening (r = 0.73, p < 0.005) and the relative thallium 201 activity (r = 0.81, p < 0.005). These results suggested that regional myocardial perfusion after myocardial revascularization in areas of old myocardial infarction distributed better to the epicardial halves than to the endocardial halves, and that the peak intensity could be related to myocardial viability.

Aged↗
PubMed1993

Long-term appraisal of coronary bypass operations in familial hypercholesterolemia.

Long-term results of coronary artery bypass grafting (CABG) in consecutive 32 patients with familial hypercholesterolemia, 6 homozygotes and 26 heterozygotes between 1976 and 1990, were analyzed. Seventeen patients in the early series underwent CABG with vein grafts alone. Subsequently, 15 patients underwent CABG with internal mammary artery grafting to the left anterior descending artery and received intensive lipid-lowering treatments early after CABG. All homozygotes and 1 heterozygote received intermittent low-density lipoprotein apheresis after CABG. There was only one late noncardiac death (3%), and the actuarial rates of freedom from cardiac events (myocardial infarction, cardiac death, and angina pectoris) were 60% at 5 and 10 years for homozygotes, and 87% and 73% for heterozygotes. The cardiac event-free curve for the heterozygous familial hypercholesterolemia group was comparable with that for the random age-matched subset of patients without familial hypercholesterolemia who underwent CABG during the same period. Two of 3 homozygotes and 4 of 14 heterozygotes in the early series had one or more cardiac events, whereas no patients in the late period had cardiac events. The patency rate of internal mammary artery grafts to the left anterior descending artery from 1 to 3 years after CABG was significantly higher than that of vein grafts to the left anterior descending artery (92 versus 45%; p < 0.05). Abdominal aortic aneurysm developed postoperatively in 2 homozygotes and 2 heterozygotes without sufficient cholesterol reduction. In conclusion, internal mammary artery grafting in combination with postoperative intensive lipid-lowering treatments, including low-density lipoprotein apheresis, may provide acceptably good long-term results of coronary revascularization in patients with FH.

Actuarial Analysis↗
PubMed1993

Renal hypouricemia due to enhanced tubular secretion of urate associated with urolithiasis: successful treatment of urolithiasis by alkalization of urine K+, Na(+)-citrate.

We encountered a case of hypouricemia with increases both in urate clearance (Cur) and in the ratio of Cur to creatinine clearance (Cur/Ccr), the normal daily urinary excretion of urate, and urolithiasis. Pyrazinamide markedly decreased Cur and Cur/Ccr, and both probenecid and benzbromarone markedly increased Cur and Cur/Ccr, however, benzbromarone did not increase either Cur or Cur/Ccr under pretreatment with pyrazinamide in the patient. Thus, the diagnosis was made of renal hypouricemia due to enhanced tubular secretion of urate. The urinary pH of the patient tended to be acidic. Three months after the start of alkalization of the patient's urine by K+, Na(+)-citrate, both urolithiasis and the symptoms related to urolithiasis disappeared. These results suggest that renal hypouricemia due to enhanced tubular secretion of urate can result in urolithiasis and the alkalization of urine may be an effective treatment for uric acid stones.

Benzbromarone↗
PubMed1993

[Treatment for cardiac rupture following acute myocardial infarction].

We experienced thirty-three patients with cardiac free wall rupture following acute myocardial infarction (AMI). Twelve patients received reperfusion therapy. Surgical closure of cardiac rupture was performed in twelve patients under cardiopulmonary bypass (CPB). Two of these patients were placed on percutaneous cardiopulmonary support system (PCPS) immediately after the onset of blow out rupture. Cardiac rupture occurred in 19 patients within 3 days from the onset of AMI (early rupture) and in 14 patients 4 days after the onset (delayed rupture). All five patients with successful reperfusion were in the early rupture group, while there were no patients with successful reperfusion in the delayed rupture group. In 12 surgical patients, 7 patients had blow out rupture and 5 patients had oozing rupture. In 7 patients with blow out rupture, four patients could not be disconnected from CPB and 2 patients had cerebral death. One patient received PCPS support showed no mental disturbance after surgery, but he died of renal failure 6 days after surgery. Three out of 5 patients with oozing rupture survived. The interval from the onset of hypotension to establishment of cardiopulmonary support was 5 minutes and 60 minutes in two patients using PCPS. However it averaged 94 minutes in 5 patients using usual CPB. It is suggested that early reperfusion therapy may prevent delayed cardiac rupture following AMI, and surgical therapy using PCPS may be useful for the treatment of cardiac blow out rupture.

Adult↗
PubMed1993

[Antireflux operation for vesicoureteral reflux in spina bifida patients].

A series of 32 patients with spina bifida, representing 50 renal units with vesicoureteral reflux (VUR), was treated with antireflux operation. All but one patient underwent ureteral reimplantation with Cohen's technique. Another patient was treated with bilateral Politano-Leadbetter's technique. The overall success rates were 92.0% by renal unit and 87.5% by case, with a mean follow-up period of 42.5 months. These results were comparable to those in the recent literature. Failure included recurrence of VUR in 3 patients. Another patient who had undergone unilateral reimplantation developed new occurrence of reflux in the contralateral ureter. Possible masking of contralateral VUR should be taken into consideration in patients with unilateral high grade VUR. We also emphasize the importance of continuing clean intermittent catheterization in a proper manner to be free of VUR postoperatively.

Adolescent↗
PubMed1993

[Unresolved issues concerning the operative indication of augmentation cystoplasty in spina bifida patients: a report of two cases].

Augmentation cystoplasty is evolving into a common method of surgical treatment for a low capacity and/or low compliance neurogenic bladder. Although an increasing number of successful results have been recently reported, the operative indication of augmentation cystoplasty is yet to be established. Herein, we report two cases of neurogenic bladder due to spina bifida which required abandonment of augmentation cystoplasty. The first case was in a 23-year-old female with a severely deformed bladder and right vesicoureteral reflux (VUR). She refused to undergo ileocystoplasty because we could not assure her of postoperative conception which she eagerly anticipated. The second case was in a 19-year-old male with a severely deformed bladder and right VUR. He experienced recurrent episodes of ventriculoperitoneal shunt (V-P shunt) difficulty which required exchanging the shunt tube each time, and each exchange proved to be very difficult or nearly impossible. Based on lengthy neurosurgical consultation, we came to the conclusion that ileocystoplasty was not a preferable treatment of choice for the correction of his disease due to the possibility of V-P shunt infection, which could be fatal. Alternatively, both cases were treated with Cohen's ureteral reimplantation, which resulted in the recurrence of VUR. These cases presented still unresolved issues concerning the operative indication of augmentation cystoplasty in spina bifida patients.

Adult↗
PubMed1992

Studies on the synthesis of sesquiterpene lactones, 14. Syntheses of (-)-arbusclin D and (+)-4-EPI-arbusclin D: the stereochemical assignment of arbusclin D.

Efficient syntheses of (-)-arbusclin D and (+)-4-epi-arbusclin D are reported. By these syntheses the C-4 stereochemistry of arbusclin D and the absolute configuration of (-)-arbusclin D have been determined to be a s shown in structure 1. The biological activities, such as cytotoxic activity toward P-388 lymphocytic leukemia, plant growth regulating activity, and antimicrobial activity of compounds 1, 3, 7, 9, 12, and 14 were also studied.

Animals↗
PubMed1992

Salmonella colitis: assessment with double-contrast barium enema examination in seven patients.

To completely rule out the possibility of ulcerative colitis, Crohn disease, and other diseases, the authors analyzed the radiographic findings at double-contrast barium enema examination performed in seven patients with colitis caused by Salmonella organisms. In all patients, bacteriologic confirmation of nontyphoid Salmonella infection and radiographs of the upper gastrointestinal tract were obtained. Total colonoscopy was performed in five patients and sigmoidoscopy in one patient. In all patients, the radiographic findings were retrospectively analyzed. The descending colon and sigmoid colon were affected in six patients, whereas the rectum was affected in none. The findings included fine mucosal granularity (seven patients), loss of haustration (six patients), many fine ulcerations (five patients), and multiple ulcers (two patients). The radiographic features simulated those of ulcerative colitis, except for absence of rectal abnormality. It is concluded that double-contrast barium enema examination is useful for detection of fine mucosal changes.

Adolescent↗
PubMed1992

Preoperative and postoperative right ventricular function during exercise in patients with mitral stenosis.

To elucidate the effects of mitral valve surgery on right ventricular function in 11 patients with mitral stenosis, pre- and postoperative right ventricular function were quantified using gated equilibrium blood pool radionuclide ventriculography at rest and during exercise. The preoperative right ventricular ejection fraction was 39 +/- 4% at rest and 36 +/- 9% during exercise, which during exercise was lower than control values (51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction was lower during exercise than at rest, postoperative right ventricular ejection fraction during exercise was lower than normal values (42 +/- 3% versus 51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction did not decrease during exercise, the postoperative right ventricular ejection fraction was within normal limits during exercise (54 +/- 5%). In addition, postoperative right ventricular ejection fraction during exercise increased to normal values in patients whose preoperative right ventricular ejection fraction during exercise had been 40% or higher. Preoperative peak ejection rate was -1.81 +/- 0.19 EDV/sec at rest and -1.72 +/- 0.39 EDV/sec during exercise, which during exercise was lower than control values (-2.44 +/- 0.53 EDV/sec) (p < 0.01). Postoperatively, peak ejection rate during exercise (-2.50 +/- 0.37 EDV/sec) increased (p < 0.05) to normal levels. Preoperative peak filling rate was 1.61 +/- 0.47 EDV/sec at rest and 1.88 +/- 0.54 EDV/sec during exercise, which during exercise was lower than control values (2.58 +/- 0.62 EDV/sec) (p < 0.01). Postoperatively, peak filling rate during exercise (2.82 +/- 0.62 EDV/sec) increased (p < 0.05) to normal values in all patients. Preoperative changes in both right ventricular ejection fraction and peak ejection rate from rest to exercise inversely correlated with the preoperative pulmonary vascular resistance at rest (right ventricular ejection fraction, r = -0.79, p < 0.005; and peak ejection rate, r = -0.67, p < 0.05). In conclusion, right ventricular systolic function improved in about half of the patients with mitral stenosis, and diastolic function improved in all patients during exercise following surgery. When the preoperative pulmonary vascular resistance was elevated, the right ventricular systolic dysfunction persisted.

Adult↗