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Biomedical subjects

T Tanishima

Publications and source records attributed to T Tanishima.

At least 19 recordsLinked to original sources
PubMed2001

Factors in the natural history of chronic subdural hematomas that influence their postoperative recurrence.

OBJECT: Factors affecting the postoperative recurrence of chronic subdural hematomas (CSDHs) have not been sufficiently investigated. The authors have attempted to determine features of CSDHs that are associated with a high or low recurrence rate on the basis of the natural history of these lesions and their intracranial extension. METHODS: One hundred six patients (82 men and 24 women) harboring 126 CSDHs who were treated at Tokyo Kosei Nenkin Hospital between January 1989 and April 1998 were studied. Types of CSDHs were classified according to hematoma density and internal architecture, and the intracranial extension of the hematomas were investigated. The postoperative recurrence rate was calculated for each factor. Based on the internal architecture and density of each hematoma, the CSDHs were classified into four types, including homogeneous, laminar, separated, and trabecular types. The recurrence rate associated with the separated type was high, whereas that associated with the trabecular type was low. Chronic subdural hematomas are believed to develop initially as the homogeneous type, after which they sometimes progress to the laminar type. A mature CSDH is represented by the separated stage and the hematoma eventually passes through the trabecular stage during absorption. Based on the intracranial extension of each hematoma, CSDHs were classified into three types, including convexity, cranial base, and interhemispheric types. The recurrence rate of cranial base CSDHs was high and that of convexity CSDHs was low. CONCLUSIONS: Classification of CSDHs according to the internal architecture and intracranial extension may be useful for predicting the risk of postoperative recurrence.

Adult↗
PubMed2000

Relationship between drainage catheter location and postoperative recurrence of chronic subdural hematoma after burr-hole irrigation and closed-system drainage.

OBJECT: This study was conducted to determine the best position for the subdural drainage catheter to achieve a low recurrence rate after burr-hole irrigation and closed-system drainage of chronic subdural hematoma (CSDH). METHODS: The authors studied 63 patients with CSDH in whom the drainage catheter tip was randomly placed and precisely determined on postoperative computerized tomography (CT) scans and 104 patients with CSDH in whom CT scans were obtained 7 days postsurgery. The location of the subdural drainage catheter, the maximum postoperative width of the subdural space, and the percentage of the ipsilateral subdural space occupied by air postoperatively were determined and compared with the postoperative recurrence and reoperation rates. Patients with parietal or occipital drainage had a higher rate of CSDH recurrence and much more subdural air than those with frontal drainage. In addition, patients with residual subdural air demonstrated on CT scans obtained 7 days postsurgery also had a higher recurrence rate than those without subdural air collections. Furthermore, patients with a subdural space wider than 10 mm on CT scans obtained 7 days postsurgery had a higher recurrence rate than those with a space measuring 10 mm or less. CONCLUSIONS: The incidence of postoperative fluid reaccumulation seems to be reduced by placing the tip of the drainage catheter in the frontal convexity and by removing subdural air during or after surgery.

Adult↗
PubMed1997

Development and prevention of frozen shoulder after acute aneurysm surgery.

BACKGROUND: We conducted a study on periarthritis humeroscapularis or "frozen shoulder," a postoperative complication of aneurysm surgery. The purpose of this study was to seek the cause of this complication and the methods of preventing it in patients who undergo aneurysm surgery. METHODS: The diagnosis of frozen shoulder was based on the clinical presence of shoulder pain and difficulty in raising arms that developed within 3 months of surgery. Sixty-four patients who underwent aneurysm surgery with no motor deficit were examined and classified into three groups: (1) early surgery (29 patients in the acute stage after subarachnoid hemorrhage); (2) delayed surgery (19 patients in the chronic stage); and (3) elective surgery (16 patients with unruptured aneurysms). RESULTS: The incidence of frozen shoulder was 41% in the early surgery group, 16% in the delayed surgery group, and 13% in the elective surgery group. The highest incidence of frozen shoulder was found to occur in the early surgery group and was attributed to the immobility of their upper extremities during postoperative treatment. Since patients who undergo surgery in the acute stage are often delirious and confused for several days after surgery, their arms are tied down by their sides in order to prevent them from inadvertently removing catheters such as the one for ventricular drainage. It seems that this manner of immobilizing the patient's arms is the cause of the development of frozen shoulder: Our study showed that if each arm was passively raised by turns above the patient's shoulder, the patient was able to maintain the range of motion of the upper arms and was less likely to develop frozen shoulder. CONCLUSION: Inactivity of the shoulder joints due to immobilizing the upper extremities of patients after acute aneurysm surgery seemed to cause the development of frozen shoulder. The incidence of this complication was greatly reduced by keeping the patient's upper arms raised alternately to maintain their range of motion after acute aneurysm surgery.

Craniotomy↗
PubMed1997

[Rapidly enlarging supratentorial ependymoma in a child presenting initially with a small calcified lesion: case report].

The authors report an unusual case of a 11-year-old boy whose supratentorial ependymoma showed rapid growth. He had had generalized convulsive seizures when he was 9 years old. On an initial CT scan a small calcified lesion was identified adjacent to the right sensorimotor cortex. Repeated CT scans showed no interval change in the size of the tumor for 16 months. Then, he suffered an acute onset of left hemiparesis. The neuroimaging studies demonstrated a huge tumor with a large cyst in the right parietal region which had not been observed on CT scan 7 months before. Total removal of the tumor was performed and the histopathological diagnosis was ependymoma with no evidence of malignancy. However, MIB-1 staining of the specimen revealed a high index of 1 proliferative potential up to 25% in some area. The high score of MIB-1 staining correlated well with the rapid clinical course of this histologically benign ependymoma. The small calcified lesion demonstrated on the initial CT scan in this case is considered to have been a low grade ependymoma and to have abruptly transformed into a higher grade, one resulting in rapid enlargement. The authors stress that small intracranial calcified lesions should be carefully followed up by repeated neuroimaging studies at short intervals.

Calcinosis↗
PubMed1990

New wound-healing model using cultured corneal endothelial cells. 1. Quantitative study of healing process.

A new in vitro model to evaluate the corneal endothelial wound-healing process was developed. Confluent monolayer cell sheets of either rabbit or bovine corneal endothelial cells were cultured on cover slips, the surface of which had been precoated with hydroxyethyl methacrylate (HEMA) except for the 8 mm-diameter area for cell culture. Wounds were made by scraping off cells in the center of the cell sheets using a rotating silicone tip. The areas of these wounds were measured by a method of computed planimetry. The average wound area was 3.00 +/- 0.21 mm2 in rabbit cell cultures and 3.18 +/- 0.28 mm2 in bovine. The healing process after the wounding was observed using an inverted phase contrast microscope and wound-healing rates (healed area per hour) were calculated. Wounded areas were recovered by 60 hours in rabbit experiments, and by 84 hours in bovine experiments. Wound-healing rates were different among the observation periods and showed differences between the two species. The healing rates in the rabbit were higher than those in the bovine in the early phase. This in vitro model can be used for quantitative evaluation of the wound-healing process of the corneal endothelium.

Animals↗
PubMed1990

New wound-healing model using cultured bovine corneal endothelial cells. 2. Role of migration and mitosis studied by immunohistochemistry.

The roles of migration and mitosis in the in vitro corneal endothelial wound-healing process were studied using an immunohistochemical method. The in vitro wound-healing model was a cultured cell sheet prepared using bovine corneal endothelium, and the wound was made at the center of the cell sheet using a rotating silicon tip. Following the wounding, specimens were incubated with bromodeoxyuridine (BrdU) for 12 hours. After the fixation with 10% phosphate-buffered formalin, the cells incorporating BrdU were stained by the avidin biotin peroxidase complex method. In 12 hours after the wounding, no stained cells were observed. In 24 hours, cell migration had started and a few cells were stained; the average number of stained cells was 14.6 +/- 4.0 cells/mm2. In 48 hours, the number of stained cells increased. The maximum number of stained cells was observed between 48 and 60 hours after the wounding. The number of stained cells decreased rapidly after 72 hours when the wound was almost closed. Stained cells were most numerous in the area within 0.8 mm of the wound edge throughout the wound-healing. The endothelial wound-healing process in this model could be divided into four phases, latent, migration, concurrence of migration and mitosis, and inhibition phases. This in vitro wound-healing model could simulate the wound-healing process in vivo and will be useful for a quantitative evaluation of drug effects on the corneal endothelial wound-healing.

Animals↗
PubMed1989

[A new wound healing model using tissue cultured corneal endothelium. 1. Quantitative study of healing process].

A new in vitro model for evaluating endothelial wound healing has been developed. Rabbit and bovine corneal endothelial cells were cultured on coverslips in areas 8mm in diameter with hydroxyethyl methacrylate (HEMA) and monolayer sheets were obtained. Wounds were produced by scraping cells in the center of the cell sheets with a rotating silicone tip. The areas of these wounds were measured with computed planimetry. The average wound area was 3.00 +/- 0.21 mm2 in rabbit cell cultures 3.18 +/- 0.28 mm2 in bovine cell cultures. The healing process after making the wound was observed by inverse phase contrast microscope and wound healing rates were calculated. Wounded areas were covered by 60 hours in rabbit cultures, and by 84 hours in bovine cultures respectively. Wound healing rates during 6-12 and 12-24 hours were 92.5 +/- 11.9 microns 2/h, 62.4 +/- 3.4 microns 2/h in rabbits and 10.6 +/- 3.6 microns 2/h, 62.9 +/- 7.8 microns 2/h in bovine material respectively. The healing rates were higher in rabbit cultures than in bovine cultures. This model can be used for quantitative evaluation of the wound healing process of corneal endothelium.

Animals↗
PubMed1989

[Kinetic study of cell proliferation in a new wound healing model using tissue cultured corneal endothelial cells].

We studied cell kinetics in the wound healing process using cultured bovine corneal endothelium. We cultured bovine endothelial cells on coverslips coated by hydroxyethyl methacrylate (HEMA) which had on 8 mm HEMA-free zone in diameter, and produced wounds at the center of the monolayer cell sheets using a rotating silicone tip. At various time periods after injury, we added bromodeoxyuridine (BrdU) to the medium and incubated for 12 hours. Then, the specimens with fixed 10% phosphate-buffered formalin and were incubated with a monoclonal antibody against BrdU. The cells incorporating BrdU into DNA were stained by the Avidin Biotin Peroxidase Complex (ABC) method. At 12 hours, no labeled cells were observed. At 24 hours, 14.6 +/- 4.0 cells were stained. The maximum labeling occurred during 48-60 hours after the wound. Seventy two hours after the wound, labeled cells decreased rapidly. Labeled cells were localized within 0.6mm from the wound edge throughout the wound healing process. It can be thought that the wound healing process comprised four phases, i.e., latent, migration, migration plus mitosis, and contact inhibition phases. The first is the latent phase observed during the first six hours after wound infliction. The cells respond to external expansion. The second phase in the migration phase which is last until 24 hours after wound infliction, and occurs mainly through cellular migration, while proliferation has only a minor contribution in this phase. The third is the migration plus mitosis phase. The cell proliferation shows a rapid increase after 72 hours after wound infliction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Actin in wound-healing of rabbit corneal endothelium. I. Study by immunoperoxidase method.

The distribution of actin in the rabbit cornea was examined by the indirect immunoperoxidase method using mouse monoclonal anti-actin IgM and goat anti-mouse IgM serum conjugated with peroxidase, which was stained with 4-chloronaphthol. Flat preparation of the cornea was made and the actin distribution was examined in the normal endothelium and also during wound-healing of the endothelium that took place after transcorneal freezing. In the normal cornea, the epithelial, stromal and endothelial cells contained actin in the cytoplasm. Diffuse actin staining in the endothelial cytoplasm was observed in the flat preparation of the normal endothelium. After endothelial damage, the cells adjacent to the damaged area showed a fiber-like staining of actin around the nucleus; this occurred 12 to 24 hours after the freezing. Punctate staining was seen on the 2nd day, and the intensity of the staining was maximum on the 3rd day when the wound was completely covered. On the 3rd day, fibroblast-like cells were encountered and a long fiber-like staining of actin was seen in the cytoplasm, but the staining disappeared on the 4th day. The long fiber-like and punctate staining reappeared on the 14th day. Normal staining pattern was recovered on the 28th day. These findings suggest that actin production was accelerated in the endothelial cells during the wound-healing, and that this productive activity returned to normal levels as healing was completed.

Actins↗
PubMed1987

Actin in wound-healing of rabbit corneal endothelium. II. Study by nitrobenzoxadiazole-phallacidin method.

The distribution of F-actin in the rabbit corneal endothelial cells was studied in vivo and in culture using nitrobenzoxadiazole-conjugated phallacidin. In the normal cornea, the fluorescence showing the presence of F-actin was observed along the membrane of the endothelial cells, but little fluorescence was seen in the cytoplasm. During wound-healing processes after transcorneal freezing, the endothelial cells migrating to the wound area showed abundant fiber-like fluorescence in the cytoplasm. In about 28 days after the injury, the endothelial cells recovered normal shape and the pattern of actin localization became normal, ie, fiber-like fluorescence localization along the cell membrane. The endothelial cells were cultured for about one week and the explants were removed. After further culture for about two weeks the cultured cells became confluent forming a monolayer. At the center of this monolayer, a small wound was made, and changes in the cell shape and actin distribution were studied. The actin distribution in the undisturbed monolayer cells was similar to that seen in vivo, ie, fiber-like fluorescence along the cell membrane. After the wound production, many cells were seen to migrate toward the wound center, and abundant fluorescent fiber-like structures were observed throughout the cytoplasm. Addition of cytochalasin B to the culture medium suppressed cell migration in a dose-dependent manner. At a high cytochalasin B concentration the fiber-like fluorescence was not formed and scattered fluorescent speckles were observed. Further culture in cytochalasin B-free medium after exposure to this agent permitted a recovery of cell migration and formation of the fiber-like actin fluorescence. It was suggested that polymerization of actin filaments is activated in the migrating cells during wound-healing, and that cytochalasin B reversibly blocks this polymerization, thereby suppressing cell migration. Actin filament polymerization would constitute a significant part of the mechanism underlying cell migration and wound-healing.

Actins↗
PubMed1986

Electron microscopic observations of Descemet's membrane of peripheral cornea.

The posterior portion of the Descemet's membrane was studied by scanning and transmission electron microscopy; the materials comprised 87 human peripheral corneas with ages from 2 to 98 years, 5 monkey corneas and 4 rabbit corneas. In some specimens, the endothelium was removed by ultrasonication. After removal of the endothelium, "curly structures" were recognized on the surface of the Descemet's membrane, where the membrane showed a gradual thinning. These structures appeared along the whole circumference of the cornea with variable width in the human specimens, but in monkey and rabbit corneas, the extent of these structures was less than in the human cornea. The "curly structures" were not encountered in young subjects, and they increased with age. There was a positive correlation (r = 0.60, P less than 0.001) between the age and the extent of these structures. Other aging products of the Descemet's membrane, ie, Hassall-Henle bodies, were partly surrounded by the "curly structures". The human "curly structures" consisted of collagen fibrils, halo structures in the collagen bundles, wide-spacing fibers, microfibrils, ground substances containing minute filaments and a structure resembling the Descemet's membrane. Components of "curly structures" of the monkey and rabbit were almost the same as those of the human except for the Descemet's membrane-like structure.

Aging↗
PubMed1985

Pathophysiology and pharmacology of intraocular surgery.

Meticulous studies of the pathophysiology of postoperative eyes are mandatory to find the means of reducing the risks of intraocular surgery. Various methods of examination developed for this purpose are described and their clinical significance discussed. The corneal endothelium shows no proliferative capacity even after injury and great care must be taken to protect this vulnerable cell layer. Drugs may be toxic to the corneal endothelium and their use during surgery must be exercised with caution. The intraocular irrigating solutions must contain calcium and have an appropriate salt composition. Pupillary constriction that occurs during extracapsular cataract extraction is due mainly to prostaglandins synthesized as a result of surgical trauma; this can be prevented by the preoperative use of topical indomethacin. Breakdown of the blood-aqueous barrier after intraocular surgery may also be due to a similar mechanism, and preoperative topical non-steroidal anti-inflammatory agents (indomethacin, flurbiprofen and diclofenac) can prevent this phenomenon, as studied by fluorophotometry. Topical indomethacin also prevents cystoid macular oedema after cataract surgery. Based on the biochemical findings on inflammation after tissue injury, a protocol for the preoperative and postoperative use of corticosteroid and non-steroidal anti-inflammatory agents is proposed for anterior segment surgery.

Anterior Eye Segment↗
PubMed1985

Endothelial wound-healing in penetrating corneal graft for experimental bullous keratopathy in rabbit.

Persistent bullous keratopathy was produced in one eye of a rabbit by anterior chamber irrigation with benzalkonium chloride solution (BAK). Corneal grafts were made from both eyes of another rabbit and they were transplanted to the eye with bullous keratopathy and the normal fellow eye, which served as the control. Subsequently, at intervals flat preparations of the endothelium of both eyes stained with silver nitrate were made. On panoramic photographs of the endothelium along one meridian of the cornea, the endothelial cell sizes were determined on both sides of the host-graft junction and at every 1 mm from the junction. In the control eyes the cell sizes increased, in the early postoperative period, near the host-graft junction both in the graft and in the host, and this increase gradually diminished by the end of the 6-month observation period. However, even after 6 months the mean cell size in both graft and host was slightly larger than the normal cell size. In the eye with bullous keratopathy, the cell size in the graft center increased rapidly and progressively. After 3 months the endothelial cells were seen in the host cornea and the cell sizes were considerably larger than those in the control cornea. After 6 months the cells were seen even in the periphery of the host cornea. In three sets of experiments, bullous keratopathy was produced in one eye of a male rabbit and the graft from a female rabbit was transplanted. Four months later, the detection frequency of the sex chromatin stained with acetic orcein was similar between the cells in the graft and in the host bullous cornea, indicating that the cells in the host had migrated from the graft.

Animals↗