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Biomedical subjects

H Osada

Publications and source records attributed to H Osada.

At least 343 records · Page 19Linked to original sources

Efficacy and complications of the Gianturco-Z tracheobronchial stent for malignant airway stenosis.

PURPOSE: To describe our experience using the Gianturco Z-stent (G-Z stent) for the management of malignant tracheobronchial stenosis, with special reference to complications. METHODS: Thirty-six stents were used in 22 patients with 28 lesions. Thirteen patients were grade 5 according to the Hugh-Jones classification. The technical success rates, follow-up results, and complications were reviewed on the basis of the patients' charts and radiographs. RESULTS: All stents were successfully placed in the ideal position without procedure-related complications. After the procedure, respiratory status improved in 95% (21/22) of patients, and performance status improved in 77% (17/22). Mean survival after stent placement was 15 weeks. Four patients suffered from increased thick secretions requiring multiple suctioning and aspiration by bronchoscopy. One of these patients died from asphyxiation 2 weeks after placement. Stent disruption and/or migration was observed in six patients. Of these six, four experienced life-threatening hemoptysis; all four had received aggressive anticancer treatment. CONCLUSION: G-Z stents are useful for palliation of malignant tracheobronchial obstruction. However, complications of stent strut fracture and migration give cause for concern.

Aged↗

Oligodendroglioma with cystic component in infant.

In this report, we examine the case of a 6-year-old girl with a mixed oligodendroglioma demonstrating uncommon neuroradiological images. CT and MR showed an intratemporal mass with multilocular cystic formation and intratumoral massive calcification, suggestive either of astrocytoma, dysembryoplastic neuroepithelial tumor, or ganglioglioma as a presumptive differential diagnosis. The tumor was almost completely removed. Post-operative histological examination revealed a mixed oligodendroglioma with a small component of astrocytoma. The combination of radiotherapy and chemical treatment was supplemented.

Antineoplastic Agents↗

Effects of an oil contrast medium on fertilization in the oviduct in rabbits.

The influence of an oil contrast medium on fertilization in rabbit oviducts was investigated. The oil contrast medium (Lipiodol-UF) was injected into the catheterized oviducts of anaesthetized animals, and they were mated 1, 3, 5 or 7 days later. When mating took place 1 day after injection, none of the ova that were subsequently recovered were fertilized; the fertilization rates when mating occurred 3, 5 or 7 days after injection of the medium were 78.9, 90 and 100%. Fertilization within the oviduct was, thus, impaired by the injection of oil contrast medium, but appeared to be fully recovered 7 days later.

Animals↗

Pregnancy by tubal insemination in rabbits using sperm cells capacitated in vitro.

It has been suggested that the mechanical interference involved in inserting a tube into the oviduct before ovulation, during tubal insemination, may impair the capacity of the tubal fimbriae to pick up ovulated eggs. When fresh sperm cells are used, the semen has to be injected into the oviduct before ovulation to allow time for sperm capacitation. In the present study in rabbits, sperm cells capacitated by pre-incubation in vitro were injected into the oviducts through the tubal fimbriae after ovulation. Two of the six rabbits inseminated became pregnant and gave birth to one and three offspring, respectively. Injecting capacitated sperm cells after ovulation may avoid the potential problems posed by mechanical damage of the tubal fimbriae.

Animals↗

Inhibitory effects of indomethacin on implantation and its related phenomena.

The dose-response relationship for the inhibitory effect of indomethacin on implantation and continuance of pregnancy was examined in four groups of rabbits administered with indomethacin (2.5, 5.0, 7.5 and 10.0 mg/kg) during the implantation period and compared with a control group. Implanted fetuses and corpora lutea were counted by laparotomy, and the number of offspring born was noted. The inhibitory effect of indomethacin on implantation was found to be dose-dependent, and the birth rate decreased in the indomethacin groups compared with the control group. As a result, even where implantation had been achieved, death of the implanted fetuses occurred at a high rate in rabbits administered with indomethacin during the implantation period.

Animals↗

Cleavage of unfertilized eggs after repeated administration of human chorionic gonadotrophin to hamsters.

The proportions of unfertilized eggs in the oviducts, showing abnormal cleavage, were examined in hamsters given single or repeated doses of 30 i.u. human gonadotrophic hormone for the induction of ovulation. In control animals (n = 7), 1.7% of the total ovulated eggs were morphologically abnormal unfertilized eggs showing cleavage. The proportions of unfertilized eggs that were abnormal in the groups of seven hamsters treated with one, two or three doses of the gonadotrophin were 20.4%, 19.4%, and 30.4%, respectively. The proportion of unfertilized eggs showing abnormal cleavage thus appeared to increase with repeated administrations of gonadotrophin.

Animals↗

Reduction of hamster egg abnormalities in repeatedly induced ovulation by using the minimum effective dose of human chorionic gonadotrophin.

The minimum dose of human chorionic gonadotrophin needed to induce ovulation was determined in hamsters, in which the luteinizing hormone surge was blocked by administration of phenobarbitone. Doses of 1.0, 2.5, 5.0 and 10.0 IU human chorionic gonadotrophin were injected subcutaneously, and 5.0 IU was found to be the minimum dose needed to induce ovulation in all of a group of seven hamsters. When this minimum dose was used to induce ovulation repeatedly, one, two or three times, in groups of seven hamsters the percentages of abnormal eggs seen were 5.3%, 5.6% and 6.4%, respectively. These results indicate that the marked increases in the proportions of abnormal eggs produced when ovulation is repeatedly induced, which have been observed in previous studies, can be prevented by using the minimum effective dose of human chorionic gonadotrophin.

Animals↗

Investigation of ovum transport in the oviduct: the dynamics of oviductal fluids in domestic rabbits.

Ova are captured by the oviductal fimbria and rapidly transported to the ampullary-isthmic junction of the fallopian tube. Fertilized ova and oviductal fluids are then carried medially in the fallopian tube, while undergoing maturation in preparation for entering the uterine cavity, where nidation and further development take place. This movement of oviductal fluids was visualized in a rabbit model with human chorionic gonadotropin-induced ovulation, by injection of a contrast medium into the ampulla region of the oviduct. In the ampulla, the opaque medium was observed to oscillate at 0-85.4 mm/s. This medial transport of the fluid towards the uterus decreased to 0-9.6 mm/s in the isthmic portion of the tube. This decrease substantiates previous findings that the transport of material in the isthmic portion of the oviduct is more strongly under the control of ciliary action than under peristaltic activity.

Animals↗

Influence of ageing on blastogenesis of mouse thymocytes in response to concanavalin A.

The influence of ageing on the blastogenic response of mouse thymocytes to a mitogen was investigated. Thymocytes from mice of various ages (10-70 days) were incubated with the mitogen, concanavalin A, to induce blastogenesis. The thymocytes were then incubated with [3H]thymidine, and the radioactivity of [3H]thymidine taken up by the cells was measured. The stimulation index (ratio of radioactivity uptake by cells incubated with and without mitogen) was used as a measure of blastogenesis of thymocytes. The stimulation index of thymocytes from 10-day-old mice was 2.9; it increased with age, reaching a peak of 33.7 in 40-day-old mice and then gradually decreasing to 8.2 in 70-day-old mice. The blastogenesis of thymocytes, an indicator of thymus function, was thus found to change considerably with age.

Aging↗

The effect of cross-linked hyaluronate hydrogel on the reduction of post-surgical adhesion reformation in rabbits.

The effects of cross-linked hyaluronate hydrogel and liquid sodium hyaluronate on post-surgical adhesion reformation were examined using a rabbit model. Primary adhesions in the ileocaecal region of Japanese white rabbits were induced by mechanical and chemical irritants during laparotomy. After 1 month the primary adhesions were lysed by microsurgery and cross-linked hyaluronate hydrogel or liquid sodium hyaluronate was applied to the lysed lesions. After 10-14 days the area of adhesion reformation was measured to assess any inhibitory effect of the test materials. Rabbits treated with cross-linked hyaluronate hydrogel showed a significant reduction in adhesion reformation area compared with liquid sodium hyaluronate or physiological saline treatment, and the area reduced to (mean +/- standard deviation) 0.6 +/- 1.95% of the original lesion. In a separate study, histological evaluation of rabbits treated with cross-linked hyaluronate hydrogel revealed a better healing pattern and a lower inflammatory response compared with controls. All these findings suggest cross-linked hyaluronate hydrogel may be a valuable anti-adhesion material to prevent post-surgical adhesion in abdominal or pelvic surgery.

Animals↗

Use of fibrin adhesive to reduce post-surgical adhesion reformation in rabbits.

Following surgery on fallopian tubes, the development of adhesions is a natural consequence of wound healing and may result in infertility. Using a rabbit model, we evaluated the anti-adhesive properties of a sponge-like equine collagen sheet (TachoComb), which is coated on one side with human fibrinogen and bovine thrombin. TachoComb is applied by affixing the sheet over the area of perforation or bleeding and acts as a haemostatic agent, capable of sealing perforations to prevent leakage. In our rabbit model, adhesions were induced by mechanical and chemical irritants during laparotomy. After a 1-month recovery period, adhesions were lysed using microsurgical techniques and TachoComb, or physiological saline applied. Evaluation of adhesion reformation was determined after a minimum of 10 days. TachoComb significantly reduced the area of adhesion reformation compared with rabbits treated using physiological saline only. Our study demonstrated that TachoComb is effective not only as a haemostatic agent, but is also capable of reducing adhesion reformation.

Animals↗

Clinical evaluation of a haemostatic and anti-adhesion preparation used to prevent post-surgical adhesion.

TachoComb consists of equine collagen in a sponge-like form coated on one side with human fibrinogen and bovine thrombin. This product functions as a haemostatic and physical barrier to inhibit post-surgical adhesion. In this study, we investigated TachoComb to control oozing in 16 patients who required haemostasis. Evaluation of post-surgical adhesion by second-look laparoscopy was performed at 3 months and 7 months after initial surgery. Observation via laparotomy during Caesarean section was also performed at 13 months, 3 years and 4 years after initial surgery. In all but one patient, no macroscopic evidence of TachoComb persistence was found. Furthermore, no de novo adhesions were detected at the TachoComb application site. We have thus demonstrated that TachoComb can be used to control oozing haemorrhage effectively from surgical sites and can prevent adhesion formation at the application site, and may thus be an effective method of preventing adhesion-induced infertility.

Adult↗