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Biomedical subjects

T Nishida

Publications and source records attributed to T Nishida.

At least 811 records · Page 45Linked to original sources
PubMedDate not supplied

Morphological changes in rabbit corneal endothelium after surgical injury.

PURPOSE: To understand the responses of the corneal endothelium to different types of surgical insults, we chronologically investigated morphologic changes in rabbit endothelial cells after injury. METHODS: We performed a mechanical incision, epithelial ablation, or excimer laser irradiation on rabbit corneas and observed the changes in the endothelial cells for up to 2 weeks after surgery under a light microscope and an electron microscope. RESULTS: Although we observed enlargements of intercellular spaces between neighboring endothelial cells, intercellular adhesion complexes were maintained and the cells joined tightly near their apexes immediately after each procedure. We observed no signs of endothelial cell degeneration after the procedures, but we did observe many Golgi apparati, rough-surfaced endoplasmic reticula, and secreted granules, indicating that the cells had been activated. After each procedure, varying periods of time were required before the intercellular junctions and spaces returned to normal. CONCLUSION: These results suggest that the different kinds of surgical injuries affected the corneal endothelium in different ways, but that the early changes were reversible.

Animals↗
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A case of noninflammatory corneal edema following anterior-posterior radial keratotomy (Sato's operation) successfully treated by topical corticosteroid.

BACKGROUND: Corticosteroids seem to affect the functions of corneal endothelial cells directly in addition to their anti-inflammatory effect. CASE: A 69-year-old man presented with blurred vision in his left eye and decreased visual acuity in both eyes. He had received anterior-posterior radial keratotomy for myopia in both eyes 40 years earlier. OBSERVATIONS: Both eyes showed mild corneal stromal edema in the pupil area. We diagnosed the condition as corneal edema secondary to cell loss and dysfunction of corneal endothelium after surgery. One month later, the stromal edema was further advanced in the left eye. Corneal thickness had increased from the initial value of 619 microm to 631 microm, and corrected visual acuity had decreased from 0.5 to 0.06. There were no signs suggesting inflammatory reaction. The left eye was then treated with topical corticosteroid eyedrops and subconjunctival corticosteroid injection. Two months later, corneal thickness had decreased to 546 microm and visual acuity had improved to 0.5. CONCLUSIONS: This case shows that topical corticosteroids may be effective in treating corneal edema by producing an anti-inflammatory effect and possibly activating the endothelium.

Administration, Topical↗
PubMedDate not supplied

Immunohistochemical study of localization of extracellular matrix after holmium YAG laser irradiation in rat cornea.

PURPOSE: To better understand the corneal responses to holmium YAG (Ho:YAG) laser irradiation, we used immunofluorescent microscopy to examine changes in the localization of the extracellular matrix components, which play important roles in the maintenance of corneal morphology and functions. METHODS: Rats were irradiated with a Ho:YAG laser. On days 1, 3, and 7 after irradiation, the eyes were enucleated and frozen. Cryosections were made with a cryostat and were stained with antibodies against type I collagen, fibronectin, type IV collagen, or laminin for immunohistochemical study. RESULTS: One day after Ho:YAG laser irradiation, contraction of the stromal collagen fibrils was observed. Keratocytes could not be observed at the irradiated stromal region on day 1 after irradiation. One week later, however, keratocytes returned to the irradiated area. Although the stromal collagen fibrils had contracted, they were stained by an antibody against type I collagen. Dense fluorescence for fibronectin was observed at the margin of the stromal acellular zone. Both laminin and type IV collagen were observed at the basement membrane under the corneal epithelium, regardless of whether or not the corneas had been irradiated. CONCLUSION: These results suggest that Ho:YAG laser irradiation might be useful for the collagen contraction of stroma, without causing serious damage to the corneal epithelium and the basement membrane.

Animals↗
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Abnormal deposition of laminin and type IV collagen at corneal epithelial basement membrane during wound healing in diabetic rats.

PURPOSE: To understand the pathophysiology of the corneal basement membrane in diabetes, we compared the localization of laminin and type IV collagen in the epithelial basement membrane during corneal epithelial wound healing in diabetic and nondiabetic rats. METHODS: Streptozotocin was used to induce diabetes in half the rats. Two weeks later, the whole corneal epithelium was debrided. Diabetic and healthy rats (3-5 per group) were sacrificed before debridement and 1, 3, and 7 days and 1 month afterwards. The localization of laminin and type IV collagen was observed in cryosections by epifluorescence microscopy. RESULTS: In unwounded corneas of both diabetic and normal rats, laminin and type IV collagen were localized in the corneal epithelial basement. The intensity of fluorescence, however, was clearly stronger in the diabetic rats. In normal rats, wounding initially removed laminin and type IV collagen, but during healing these two proteins reappeared beneath the resurfacing corneal epithelium. Although similar results were observed in diabetic rats, the expression of laminin and type IV collagen was delayed, and their deposition was fragmented and irregular. CONCLUSIONS: These results suggest that delayed corneal epithelial wound healing in diabetes might involve delayed reappearance and abnormal reformation of epithelial basement membrane proteins.

Animals↗
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Changes in extracellular matrix components after excimer laser photoablation in rat cornea.

PURPOSE: To learn more about corneal wound healing after excimer laser photoablation. METHODS: Observations were made on the chronological changes in type I collagen, fibronectin, laminin, and type IV collagen after excimer ablation of rat cornea. Immunohistochemical techniques were used. RESULTS: There was no obvious change in the localization of type I collagen in the ablated area, but the localization of fibronectin, laminin, and type IV collagen changed remarkably. One day after ablation, immunofluorescent staining for fibronectin increased on the ablated surface. Subsequently, the fluorescence of fibronectin, laminin, and type IV collagen increased remarkably; in particular, the localization of these extracellular matrix proteins was sustained in the shallow layer of the stroma until about 24 weeks after ablation. Hematoxylin-eosin staining indicated that keratocytes temporarily disappeared 1 day after ablation, and activated keratocytes then migrated to the ablated areas. CONCLUSIONS: These results suggest that activated keratocytes might be synthesizing the extracellular matrix components. Therefore sustained responses of keratocytes may be induced by excimer laser photoablation.

Animals↗
PubMedDate not supplied

Signaling regulation for synergistic effects of substance P and insulin-like growth factor-1 or epidermal growth factor on corneal epithelial migration.

PURPOSE: In a previous report we showed that substance P (SP) and insulin-like growth factor-1 (IGF-1) or epidermal growth factor (EGF) synergistically stimulate corneal epithelial migration. In this study, we used an organ culture system of rabbit cornea to identify which signal transduction system affects corneal epithelial migration. METHODS: Rabbit corneal blocks were cultured in TC-199 culture medium containing various reagents for 24 hours. After the end of cultivation, the length of the path of epithelial migration was measured. RESULTS: Acting alone, protein kinase C (PKC) inhibitors, calphostin C and H-7, each reduced the length of epithelial migration. Tyrosine kinase (TK) inhibitors, genistein and herbimycin A, also acted individually to inhibit epithelial migration. The synergistic stimulatory effects of SP and IGF-1 on corneal epithelial migration were eliminated when PKC inhibitors or TK inhibitors were added. The synergistic effect of SP and EGF was eliminated by TK inhibitors, but only partly suppressed by PKC inhibitors. CONCLUSIONS: These results suggest that the synergistic effect of SP and EGF might require a TK pathway, and that the synergistic effect of SP and IGF-1 might require both PKC and TK pathways.

Animals↗
PubMedDate not supplied

Electron microscopic observation of established chondrocytes derived from human intervertebral disc hernia (KTN-1) and role of macrophages in spontaneous regression of degenerated tissues.

BACKGROUND CONTEXT: Biological and pathological cell processes during the degeneration of intervertebral discs are as yet poorly understood. PURPOSE: An electron microscope was used to observe disc hernia degeneration at the cellular level as expressed in extruded tissue from a human intervertebral disc and in cultured chondrocytes. The mechanism of spontaneous regression was analyzed in order to investigate the effects of homologous macrophages, and the results of this analysis may be developed into a clinical therapy. STUDY DESIGN/SETTING: Extruded tissue specimens excised during surgery on human intervertebral disc hernia and cultured chondrocytes isolated from the excised tissue were observed by means of electron microscopy. Extracellular matrix metalloproteinase-3 (MMP-3) and its antagonist, tissue inhibitor of metalloproteinases-1 (TIMP-1), were observed by means of immune electron microscopy. Macrophages confirmed by CD68 immunostaining were added to the chondrocyte culture and observed by means of electron microscopy. PATIENT SAMPLE: All control subjects and patients gave written consent to the study. OUTCOME MEASURES: KTN-1 was directly observed without culture, and nuclei degeneration, the development of chromatin granules, changes in the osmotic pressure of the nuclear membrane and rough-surfaced endoplasmic reticulum, and the development of fat droplets were observed. METHODS: Tissues excised during surgery were divided, a part of the tissues were fixed in various fixatives for electron microscopy and immune electron microscopy analysis, and the other part was treated with collagenase. In addition, chondrocytes were isolated and cultured. Human peripheral blood mononuclear cells were separated using the Ficoll method. After culturing the cells, macrophages were collected, added to the chondrocyte culture, and observed under an electron microscope. CD68 positivity of the macrophages was confirmed by CD68 immunostaining. RESULTS: Freshly isolated chondrocytes in the hernia's extruded region differed markedly from cultured chondrocytes. By means of immunoelectron microscopy, MMP-3 and TIMP-1 were localized at the endoplasmic reticulum of the cultured chondrocytes. Infiltration of macrophages among the chondrocytes was observed in the mixed culture. CONCLUSIONS: The tissue extruded from the intervertebral disc showed obvious signs of degeneration, such as changes in osmotic pressure. Macrophages were observed to be the mechanism of spontaneous regression.

Cell Line↗
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Remission of metastatic cervical adenocarcinoma with weekly paclitaxel.

We report the use of paclitaxel in the successful treatment of a patient with recurrent adenocarcinoma of the cervix. Paclitaxel, 70 mg/m2 by 1-h infusion weekly, was administered to a 59-year-old patient with cervical adenocarcinoma showing lung metastasis. She showed partial clinical response after seven cycles, and at the completion of 20 cycles she showed complete response, which was confirmed by chest X-ray and computed tomography scan. Toxicities including neurotoxicity were mild. She showed an objective response to treatment for over 8 months, and she enjoyed a favorable quality of life during and after treatment. Weekly paclitaxel was very well tolerated, yet was effective for recurrent cervical adenocarcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Three-dimensional vector graphing of the H reflex.

Comparison of latencies of the H reflex from side-to-side is considered a valid indicator of pathology, but amplitudes are too variable to allow similar comparison. Three pairs of electrodes were placed circumferentially and longitudinally along the calf to record the H reflex in three axes simultaneously. An H reflex with the greatest amplitude was produced by incrementally increasing submaximal stimulation to the tibial nerve. Three-dimensional vector graphs were constructed at three levels in each calf in ten normal individuals. Best fit curve Procrustes statistical analysis showed an average of 82.2 to 90.6% agreement of 3-D shape left-to-right with greater agreement at distal levels. Standard deviation ranged from 11.3% proximally to 8.2% distally. This represents much closer agreement than established norms for amplitude, which can vary from two to four times side-to-side. Three-dimensional vector analysis holds promise to further understanding of peripheral and central electrophysiologic phenomena.

Adult↗
PubMedDate not supplied

Comparison of three methods for recording tibial H reflex: a clinical note.

Recording the tibial H reflex from the calf is routine in clinical electromyography. Two widely used methods are Hugon's and Braddom and Johnson's. Both methods produce an H wave with an initial positive deflection. Another method, the "half and half" method, generates an H wave with an initial negative deflection. To compare these methods, H-reflex responses were recorded in the right calf of 20 normal adults with each method using identical amplifier and stimulator settings. Stimulus current was increased by increments of 0.5-1.0 mA until the H reflex and motor (M) wave responses reached maximum amplitudes (Hmax, Mmax). H wave to M wave (H/M) amplitude ratios were calculated. The half-and-half method produced greatest Hmax, Mmax, and H/M ratio. Wave form configuration for the half-and-half method was biphasic with an initial negative deflection; it was triphasic with an initial positive deflection with the other methods. The shapes of M and H waves were similar in two methods but dissimilar in one. Because of the greater amplitude and the initial negative deflection, the H wave may be easier to detect with the half-and-half method and may present a latency that is more easily determined. For these reasons, the half-and-half method is recommended for measuring amplitude and latency in clinical settings.

Adult↗
PubMedDate not supplied

Phagocytosis of latex beads by the epithelial cells in the terminal region of the vas deferens of the cat: SEM and TEM study.

The present scanning and transmission electron microscopic observations of the terminal vas deferens of the cat have revealed that the epithelial cells, like luminal macrophages, are not only involved in the removal of spermatozoa as previously reported but also capable of taking up actively the latex beads injected to the lumen. In addition, orchidectomy has been shown to do not have any remarkable effects on the ability of the epithelial cells for phagocytosis of beads.

Animals↗
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Histologic grade and cellular proliferation at the deepest invasive portion correlate with the high malignancy of submucosal invasive gastric carcinoma.

To establish appropriate indications for endoscopic treatment of submucosal invasive gastric carcinoma, we investigated clinicopathologic features and proliferating cell nuclear antigen (PCNA) expression at the deepest invasive portion of 192 differentiated submucosal invasive gastric carcinomas that had been surgically resected. Lymph node metastasis was demonstrated in 30 (15.6%) of 192 lesions. Histologic heterogeneity (based on differentiation at the deepest invasive portion) was demonstrated in 36 (18.8%) of the 192 lesions. In 159 lesions, excluding 33 undifferentiated lesions at the deepest invasive portion, the depth of invasion, histologic grade, lymph vessel involvement, infiltrative growth pattern (INF) and existence of an ulceration were all significantly correlated with the incidence of lymph node metastasis. The lesions with both well-differentiated adenocarcinoma (WELL) and minimal submucosal invasion (sm1) showed no lymph node metastasis. PCNA expression was estimated in 59 good stained lesions. The mean PCNA labeling index (LI) was 50.9 +/- 7.2% in lesions with lymph node metastasis and 43.7 +/- 9.3% in those without lymph node metastasis (p < 0.05). In addition, PCNA-LI also correlated significantly with the histologic grade, depth of invasion, INF and lymph vessel involvement. These results indicate that the submucosal invasive gastric carcinoma with both WELL and sm1, which shows no other risk factors, can be considered as the appropriate indication for curative endoscopic treatment. The PCNA-LI at the deepest invasive portion is useful in understanding the biology of lymph node metastasis in submucosal invasive gastric carcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Correlation between cell killing effect and cell membrane potential after heat treatment: analysis using fluorescent dye and flow cytometry.

Exposure of mammalian cells to a temperature between 42 and 44 degrees C produces multiple effects on cellular metabolism. However, none of these effects have been demonstrated to be casually related to cell death. The plasma membrane has also been suggested to be one of the targets for hyperthermia. Hyperthermia influences the membrane fluidity and membrane fluidity affects both passive diffusion and active transport process. Here, we examined the effect of hyperthermia on the transmembrane potential V-79 cells using a lopophilic probe and flow cytometry. The underlying principle on which this method is based is that a freely diffusible cation distributes itself across the membrane according with the transmembrane potential and with the concentration gradient. By these methods, we tried to find the relation between the change of surviving fraction and membrane potential. We revealed that the membrane potential becomes to be depolarized by heat treatment between 41 and 44 degrees C immediately after heat treatment. In the relationship between the change in membrane potential and cell surviving fraction, the difference between 43 and 44 degrees C was not statistically significant but between 42 and 43 degrees C was statistically significant. These results imply that the cell membrane (potassium ion channel) is one of the targets of heat treatment and that duration of depolarized condition leads to cell death.

Animals↗
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Fibronectin appears at the site of corneal stromal wound in rabbits.

Fibronectin (FN) is present both in plasma and in extracellular matrix, and is postulated to be involved in wound healing. The appearance of FN was investigated in the wounded rabbit cornea after corneal stroma was injured with a sharp knife or after lamellar keratoplasty was performed. An indirect immunofluorescence technique was employed to detect the presence of FN. Normal, unwounded rabbit cornea showed an intensive fluorescence at Descemet's membrane. Strong specific fluorescence was observed at the edge of a stromal wound and beneath the sliding epithelial cells after non-perforating incisions. These could be detected as early as 3 hours after injury. The fluorescence became the strongest at 6 hours, and and then gradually decreased in its intensity, disappearing by about 7 days when epithelial cells entirely filled the stromal wound. In case of lamellar keratoplasty, FN was detected at the interface of the graft and the recipient cornea. These results suggest that FN plays an important role in the stromal wound healing.

Animals↗
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Changes in energy metabolism following roentgen irradiation of in vivo growing Ehrlich ascites tumour cells studied by 31P magnetic resonance spectroscopy.

The energy metabolism in Ehrlich ascites tumour cells following in vivo irradiation of a dose of 5.0 Gy was studied in vitro in their ascites fluid up to 48 hours using 31P magnetic resonance spectroscopy measuring ATP, ADP and inorganic phosphate (Pi). The results are also related to radiation induced changes in cell cycle composition. ATP was reduced by more than 50 per cent 20 to 24 hours after irradiation but normalized at 48 hours. ADP was reduced to about half the normal level 24 to 48 hours after irradiation. When the ATP and ADP had reduced levels, the inorganic phosphate increased correspondingly. Addition of glucose to the ascites cell suspension at the time of minimum ATP level immediately raised the ATP:Pi ratio. Since the glucose concentrations in blood and in ascites fluid following irradiation were also reduced, lack of glucose for energy production might have been a major contributing factor for the reduced ATP production.

Adenine Nucleotides↗
PubMedDate not supplied

Radical surgery after neoadjuvant intra-arterial chemotherapy in stage IIIb squamous cell carcinoma of the cervix.

We examined the efficacy and safety of neoadjuvant intra-arterial chemotherapy (NAC) followed by radical hysterectomy and/or radiotherapy in patients with stage IIIb cervical cancer. Treatment consisted of bilateral internal iliac artery infusion of cisplatin or carboplatin and peplomycin every 21 days for two courses. Patients who responded to NAC underwent radical surgery. Patients who did not respond to NAC were treated with pelvic radiotherapy. Complete response was achieved in 2 (7.1%) of 28 patients, while a partial response was observed in 17 (60.7%) and stable disease in 9 (32.1%) patients. Sixteen patients (57.2%) were able to undergo surgery. The median blood loss (674 ml) and operating time (232 min) for radical surgery in patients with stage IIIb disease was similar to that in patients with stages Ib to IIb disease. No intra-operative or immediate postoperative complications were observed. The 5-year disease-free survival (DFS) for patients who underwent surgery (81.3%) was higher than for patients who underwent radiotherapy after NAC (31.3%). Radical surgery after NAC for stage IIIb disease was safe, and a survival benefit followed by surgery with or without radiotherapy.

Adult↗