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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 1,225 records · Page 68Linked to original sources
PubMedDate not supplied

Mucoceles of the paranasal sinuses with intracranial extension-postoperative course.

Mucoceles of the paranasal sinuses cause progressive distension of the bony walls and induce compressive symptoms. Although rare, cases of massive intracranial extension have occurred. We believe that an endoscopic transnasal approach is the best choice for such huge mucoceles because it is the least invasive and can provide an adequate surgical field of view for wide marsupialization. However, the results of long-term follow-up after endoscopic transnasal surgery have not been reported. This study was designed to evaluate prospectively the postoperative course of patients with intracranially extended mucocele. In the last 5 years, we have operated on four patients with intracranially extended mucocele. Although postopertive scanning is not recommended routinely after surgery for inflammatory disease, we followed up two patients who consented by using magnetic resonance imaging (MRI) along with endoscopy. Dural descent to the original skull base plane necessitated long periods of follow-up, lasting 18 and 5 months, respectively. On the mucocele wall mucosa, which had been smooth during surgery, polyps and granulations developed after surgical drainage and lasted for a considerable time. Although endoscopic transnasal opening of mucocele is a method of choice, we recommend follow-up of such patients for long periods, at least until the frontal skull base dura returns to its original position.

Aged↗
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Estrogen receptor expression in the genital tract of female mice treated neonatally with diethylstilbestrol.

The distribution of the estrogen receptor (ER) was investigated immunohistochemically in the genital tract of 0 (day of birth)--to 50-day-old C57BL/Tw female mice given 5 daily injections of 2 micrograms diethylstilbestrol (DES) from the day of birth using an anti-ER monoclonal antibody. In the oviduct, cervix and vagina of control mice, both epithelial and stromal cell nuclei showed positive ER immunoreaction at 0 day. Nuclei of uterine stromal cells also showed strong ER immunostaining even at 0 day. In contrast, the ER in uterine epithelial cells began to appear by day 5. The number of positive epithelial cells and staining intensity gradually increased until 10 days. In neonatally DES-exposed mice, ER appeared in uterine epithelial cells 24 h after the injection. Polygonal cells appearing in the vaginal epithelium of DES-exposed 3-day-old mice showed weak ER staining. Neonatal DES exposure reduced staining intensity of columnar vaginal epithelial cells and uterine stromal cells at 3 days. Vaginal epithelial cells undergoing ovary-independent stratification and cornification in neonatally DES-exposed mice and normal estrous mice showed ER immunoreaction only in the basal cells.

Animals↗
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Elastofibroma dorsi. Cytologic, histologic, immunohistochemical and ultrastructural studies.

Cytologic, light and electron microscopic, and immunohistochemical studies were conducted on a case of elastofibroma. Aspiration cytology showed a characteristic "braidlike" or "fern leaf-like" structure. Immunohistochemically the accumulate was shown to be elastin. Transmission electron microscopy indicated electron-dense, granular aggregates surrounded by microfilaments and collagen, while scanning electron microscopy revealed balls with a ball-of-yarn-like structure consisting of small fibrils, probably of elastin. These structures are unique to this disease and useful for diagnosis.

Biopsy, Needle↗
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Measurement of peritoneal dialysate volume by CT.

Three-dimensional (3-D) graphic reconstruction of serial image data of x-ray CT on three dialysis patients was studied to measure peritoneal dialysate (PD) volume. Volume estimation with a surface reconstructed model provided a 16% error; a 35% error was found with a voxel model, although the total time required by the voxel model was 15 times less.

Aged↗
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Magnetic resonance imaging in chronic liver disease evaluated in relation to hepatic fibrosis--clinical and experimental results.

In 21 patients with chronic liver disease, the ratio of liver to muscle signal intensity on T1-weighted images was negatively correlated with the progression of hepatic fibrosis defined according to findings by laparoscopy and liver biopsy, and differentiated six patients with early chronic hepatitis from eight with liver cirrhosis. On T2-weighted images, the number of low intensity nodules comparable in size to regenerating nodules surrounded by connective tissues showed a positive correlation with stage. When hepatic fibrosis with no necrosis or fat infiltration was induced in rats, T2 values were positively correlated with hepatic hydroxyproline content, though there was no such correlation for T1 values. These results suggest that MR imaging may be useful for determining the progression of hepatic fibrosis in chronic liver disease. T2 values may directly reflect hepatic fibrosis.

Adult↗
PubMedDate not supplied

Computed tomography density of gallbladder stones may aid in predicting the rate of stone fragmentation with extracorporeal lithotripsy.

Thirty-six patients with gallbladder stone(s), 21 with solitary stone and 15 with multiple stones up to five in number, were treated by a single session of extracorporeal shock wave lithotripsy. In eight patients (group A), stones were gradually fragmented from the surface, producing fine powderlike fragments which made residual stones invisible, leading to reduced therapeutic efficacy. In 13 patients (group B), residual stones remained visible up to 2,400 shocks, though they showed similar fragments. Such fragments did not appear throughout treatment in 14 patients (group C). Computed tomography (CT) attenuation number, when the region of interest was settled on the whole stone, increased in the order of group A, B, and C. When the distribution of CT density on stones was analyzed, the density was diffusely lower than 50 HU in all patients in group A, higher than 50 HU only on the surface in all patients except for two in group B, and diffusely higher than 50 HU in all patients except for one in group C. CT findings may be useful for predicting the fragmentation mode of gallbladder stones by extracorporeal shock wave lithotripsy.

Adult↗
PubMedDate not supplied

Synthesis of the pro-peptide of subtilisin BPN'.

Subtilisin, a bacterial serine protease, is secreted as pre-pro-subtilisin. Previously, we demonstrated that the pro-peptide moiety of intact pro-subtilisin can guide the folding of inactive protein to active enzyme both in an intramolecular (6) and intermolecular manner (18). Herein is reported the total chemical synthesis of the pro-sequence (77 amino acids) of pre-pro-subtilisin BPN' carried out by solid phase methods. The structure was confirmed by both sequencing and amino acid analysis of the fragment peptides resulting from a V-8 protease digest. Preliminary studies indicate that the synthetic pro-peptide itself can renature denatured subtilisin BPN'. This study demonstrates a novel method for examining protein folding with the aid of exogenously added synthetic peptides.

Amino Acid Sequence↗
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Basic analysis of dynamic study in cases of hepatocellular carcinoma using inversion recovery snap shot FLASH MR imaging with Gd-DTPA.

Twenty patients with hepatocellular carcinoma were studied by dynamic sequential inversion recovery snap shot fast low angle shot (FLASH) imaging after the bolus injection of various amounts of Gd-DTPA. We determined the optimal dose of Gd-DTPA for depicting tumors as early marked enhancement and compared the method with dynamic CT by matching data acquisition time. The optimal dose was estimated to be 0.1 mmol/kg. Compared with dynamic CT, dynamic MRI showed rapid short-term enhancement in the early phase, while the contrast enhancement in the late phase lasted longer and was stronger than that of CT.

Aged↗
PubMedDate not supplied

Induction of neonatal immunologic tolerance to heart transplantation by intrathymic myocardial cell inoculation in rats.

To induce immunologic tolerance, intrathymic inoculation of myocardial cells in rats was performed during the neonatal period. Isolated myocardial cells from Wistar-Lewis (LEW/Crj) rat hearts were inoculated into the thymi of incompatible neonatal Wistar-King (WKAH/HKm) rats without use of immunosuppressants. Ten weeks later the heart from the LEW donor was transplanted heterotropically to the pretreated male WKAH rat (group 1, n = 14). As controls (groups 2 through 4), heart transplantation was performed in each of 10-week-old rats as follows: (1) The syngeneic heart was transplanted (group 2, n = 4); (2) the allogeneic heart was transplanted without use of immunosuppressants (group 2, n = 12); and (3) the allogeneic heart was transplanted with use of immunosuppressants (cyclosporine, 20 mg/kg/day, for 10 days after transplantation, (group 4, n = 5). In groups 1 through 3, four rats with heart transplants in each group were killed on the seventh day after transplantation and were histopathologically examined. No early rejection was seen in group 1. Hematoxylin-eosin staining of the thymus from the inoculated recipient revealed that donor myocardial cells continued to survive in the thymic tissue. The remaining rats in groups 1, 3, and 4 were saved for study of graft survival time. The longest proven graft survival in group 1 was 390 days, whereas it was only 7 days in group 3. These results indicated that intrathymic inoculation of donor myocardial cells in rats into incompatible neonatal recipients induced donor-specific tolerance for subsequent heart transplantation.

Animals↗
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Development and mitotic activity of the metrial gland in rat uterus during mid-pregnancy.

Development and mitotic activity of metrial gland in rat uterus were investigated focusing on the point of implantation during mid-pregnancy. In decidua basalis, the granulated metrial gland (GMG) cells slightly increased in number during days 8-12 of pregnancy and then decreased, while the cells appearing in the mesometrial triangle on day 9 continued to increase until day 16, forming the metrial gland in situ. By contrast, the mitotic change in the mesometrial triangle was similar to that in the other 2 regions, decidua basalis and the inner layer of myometrium. In all 3 regions, mitotic rate rose drastically on day 9, and then gradually decreased until day 16. However, most of the mitotic cells lacked the PAS-positive cytoplasmic granules in any regions. Mitotic activity in GMG cells was very low and almost unchanged throughout the gland development. These results suggest that the rapid rise of mitotic rate is due to the active mitosis of PAS-negative cells, presumably GMG precursor cells, existing widely in the implantation point of rat uterus during the early development of the gland. Immunocytochemical study revealed that progesterone receptors were localized in decidual and muscle cells and fibroblasts, but not in GMG cells during the development of the gland. The present study suggests that the metrial gland cells are proliferated, differentiated and maintained by the progesterone-sensitive stromal cells, such as decidual cells and/or fibroblasts.

Animals↗
PubMedDate not supplied

Purification of rabbit blood basophils by isopycnic banding on Percoll.

This study defines the basophil densities in rabbits and also describes a relatively simple method of purifying basophils from peripheral blood through a two-step procedure. To evaluate the recovery of basophils, EDTA-anticoagulated blood in layered over Percoll of various densities, ranging from 1.070 to 1.080 g/ml. The cells retained in Percoll were collected separately after centrifugation at 600 g(av) for 30 min (Step I). Distribution of basophils indicated that basophils had densities of between 1.070 and 1.078 g/ml, with a peak at 1.074 g/ml. To enhance the basophil purity, a second centrifugation of the cells obtained from Step I over appropriate Percoll gradient led to further enhancement of basophil purity (30.4 +/- 0.7%) which was (20.6 +/- 0.2%) in Step I. The cells obtained by this method appeared morphologically normal and viable.

Animals↗
PubMedDate not supplied

Effect of ovariectomy on histological change and protein expression in female mouse reproductive tracts.

Proliferation of the vagina and uterus in rodents is stimulated by ovarian estrogen, and ovariectomy induces regression of these tracts. In mouse, reproductive tracts, organ weights, vaginal epithelial thickness, the number of epithelial cell layers, and uterine epithelial cell height were significantly reduced 1 to 20 days after ovariectomy when compared with those of intact, mice taken at the estrous stage. No significant differences in those parameters were found between ovariectomized mice implanted with estradiol and intact estrous mice. Vaginal epithelium at estrus was composed of 10-15 layers of epithelial cells with superficial keratinized layers, however, the vaginal epithelium began to regress one day after ovariectomy. Infiltration of leukocytes was encountered in the vaginal epithelium 2-3 days after ovariectomy. Protein expression in the regressing vagina and uterus after ovariectomy was examined by two-dimensional polyacrylamide gel electrophoresis. After ovariectomy, new proteins appeared in the regressing vagina, but not in the regressing uterus. Expressions of 7 and 6 proteins in the vagina and uterus, respectively, reached peak levels 2-3 days after ovariectomy. The expression of ovariectomy-specific proteins and infiltration of leukocytes in vaginal epithelium was inhibited by the injection of cycloheximide, an inhibitor of protein synthesis. These results suggest that some proteins participate in the regression of mouse reproductive tracts after estrogen withdrawal induced by ovariectomy.

Animals↗
PubMedDate not supplied

Intrahepatic cholangiocarcinoma with a long-term survival of 12 years after surgical resection: report of a case and review of the literature.

The prognosis of primary liver cancer, especially cholangiocarcinoma, is extremely poor. A long term, 12 years survivor of intrahepatic cholangiocarcinoma arising in a local dilatation of the intrahepatic bile duct is presented. A 40-year-old male patient was presented with recurrent upper abdominal pain, fever, and jaundice. Computed tomography revealed a localized duct dilatation, and ultrasound clearly demonstrated a tumor mass arising within the bile duct. At surgery in March, 1982, the tumor mass was resected and histologically confirmed as a well differentiated papillary adenocarcinoma arising. In March, 1994, the patient is alive and cancer-free, 12 years after surgical resection. To our knowledge, there has been no report on a patient surviving more than 10 years after initial treatment. This case suggests that a localized cystic dilatation of the intrahepatic-bile duct on imaging modalities may harbor a bile duct carcinoma, and this in turn may contribute to early diagnosis of carcinomas and improved long term survival.

Adult↗
PubMedDate not supplied

Hypertensive changes in intratesticular arteries impair spermatogenesis of the stroke-prone spontaneously hypertensive rat.

It is reported that some elderly males exhibit both hypospermatogenesis and intratesticular arterial changes. These arterial changes are thought to contribute to spermatogenic damage. In this study the process of the damage to spermatogenesis induced by such changes was evaluated using stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP showed a rapid increase of blood pressure, followed by hypertensive vascular changes. At 23 weeks of age, 61.8% of seminiferous tubules were atrophic in SHRSP, simultaneously with the development of hypertensive vascular changes. In addition, the transferrin concentration in the cytosolic fraction of the testicular homogenate was decreased at 23 weeks of age exactly when the severe damage to the spermatogenesis was seen, suggesting that Sertoli cell function in SHRSP regressed at 23 weeks of age. Based on these findings, it was suggested that the decline in the Sertoli cell function caused by the hypertensive vascular changes is part of the mechanism whereby spermatogenic damage occurs in SHRSP.

Animals↗
PubMedDate not supplied

Manidipine improves spermatogenesis in the stroke-prone spontaneously hypertensive rat.

We evaluated the protective effects of manidipine, which is a long-lasting calcium-channel blocker, against damage to spermatogenesis arising from hypertensive vascular changes in stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP showed severe hypertension at 11 weeks of age, followed by hypertensive changes in intratesticular arterioles from 15 weeks of age. Manidipine lowered the blood pressure and the hypertensive vascular changes of intratesticular arterioles in SHRSP. The percentages of atrophic seminiferous tubules and tubules with less-differentiated germ cells were increased in SHRSP at 23 weeks of age, although the administration of manidipine preserved spermatogenesis at a normal level. The transferrin concentration in testicular cytosol was comparable, whereas insulin-like growth factor-I (IGF-I) was reduced from 19 weeks of age in SHRSP. Manidipine preserved the normal IGF-I concentration. Therefore, manidipine prevented the development of hypertensive vascular changes in the testis and maintained normal Sertoli cell function. As a result, manidipine protected spermatogenesis in SHRSP. These findings also suggested that hypertensive vascular changes in the testes play the most important role in spermatogenic damage in SHRSP.

Animals↗
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Comparison of the closing dynamics of mechanical prosthetic heart valves.

To compare the closing dynamics of mechanical tilting disk prosthetic heart valves (OmniScience 25 [OS25], Medtronic-Hall 25 [MH25], Bjork-Shiley Monostrut 29 [BS29]) and bileaflet valves (CarboMedics 29 [CM29]) in the mitral position, an x-ray high speed video camera (XHVC) and a mechanical mock circulator were used. From the continuous images taken with the XHVC, the starting point of closing and the period during closing (PDC) were measured. Pressures and flow rate were recorded at 500 Hz synchronously with the XHVC. A pressure difference across the valves at the onset of closing (dpc) was newly introduced to compare the closing response. Using 60 and 100 bpm, the following results were obtained: 1) the CM29 had less PDC and maximum backflow rate than the BS29; 2) the dpc and the PDC at 100 bpm were larger than those at 60 bpm; 3) the dpc of the MH25 was the lowest; and 4) the PDC of the CM29 was the shortest. With regard to the effect of valve design on closing dynamics, it was shown that: 1) less momentum of inertia of the occluder and disk traveling angle resulted in lower dpc and shorter PDC, and 2) the higher the dpc and the PDC became, the larger the maximum backflow rate that was generated, and 3) low final closing speed will be achieved for small disk travelling angle.

Biomechanical Phenomena↗
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Evaluation of the clamshell incision for bilateral pulmonary metastases.

To treat bilateral pulmonary metastases during a single operation, simultaneous bilateral thoracotomy via median sternotomy is usually employed. With this approach, however, it is sometimes difficult to access lesions located on the dorsal side of the left lower lobe. We have explored the use of clamshell incisions for such difficult cases. From 1990 to 1995, we studied the use of clamshell incisions in 14 patients with bilateral pulmonary metastases. The average duration of surgery was 212 minutes, the average volume of intraoperative blood loss was 477 ml, and the average number of metastatic lesions extirpated was 23. The endotracheal tube could be removed immediately after the operation in 12 patients, while the remaining 2 patients, who underwent an extensive operation, needed 3 and 4 days of intubation. The arterial blood gas analysis on the first postoperative day for the former 12 patients was as follows: the average value of PaCO2 was 44.4 mmHg, and the average value of PaO2 was 140.4 mmHg (FiO2 = 0.4). None of the patients experienced severe pain or respiratory distress that impaired their daily activities due to continuous epidural anesthesia following surgery. The length of time from surgery to discharge was relatively short, averaging 22 days. We have not encountered any sternal override in our patients. Although we cannot ignore the biological behaviour of primary tumors when selecting a surgical approach, the clamshell incision seems to provide a useful means of thoracotomy when treating bilateral pulmonary metastases. We intend to use this approach in future, taking into careful consideration the indication of each individual case.

Adolescent↗