Search PubMed⌕ Search

Biomedical subjects

M Sawa

Publications and source records attributed to M Sawa.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Immunohistochemical study of interstitial keratitis in an animal model].

PURPOSE: We performed an immunohistochemical study on the development of interstitial keratitis in a rabbit model sensitized by ovalbumin (OA). METHODS: A mixture of OA (5 micrograms/ml) and Freund's complete adjuvant was initially injected subcutaneously (0.4 ml) into the rabbits' back and footpad (0.2 ml). After a week, the rabbits were sensitized by an injection of the same solution into the back (0.5 ml) again. After 4 weeks the rabbits underwent the same treatment as a booster shot. Then a week later OA solution (0.05 ml) was injected into the corneal stroma. We observed the cornea on days 1-3, 7, and 10 after the corneal treatment. Corneas on days 3 and 10 were examined by immunohistological methods using hematoxylin-eosin stain, methylgreen pyronin stain, and by immunohistochemical methods with anti-CD 4, anti-CD 8, and anti-OA antibodies. The localization of specific antibodies was identified by fluorescent-antigen method. Electron-microscopic observation was also done. RESULTS: Rabbits developed corneal opacity and edema on day 1, corneas had on immune ring with a peak intensity on day 3, and vascularization on day 7 after corneal treatment. Microscopic examination revealed infiltration of neutrophils in to the area of the immune ring on day 3 and many plasma cells at the limbus and stroma on day 10. CD 4 positive cells were found at the limbus and stroma on days 3 and 10. CD 8 positive cells were found at the limbus and stroma only on day 10. OA positive findings were observed at the immune ring and its inner area. In the fluorescent-antigen method, specific antibodies were found in plasma cells at the limbus on days 3 and 10. CONCLUSIONS: In our experimental model of interstitial keratitis with immune ring and vascularization, the Arthus reaction was dominant. Infiltration of antigen specific plasma cells in the stroma with vascularization caused a modification of pathologic reaction in keratitis.

Animals↗
PubMed1999

Metastatic seeding of bile duct carcinoma in the transhepatic catheter tract: report of a case.

We describe herein the case of a 51-year-old woman in whom metastatic tumor seeding of the percutanenous transhepatic biliary drainage tract occurred following a pancreatoduodenectomy for carcinoma of the distal common bile duct. An abdominal computed tomography scan done 6 months after the initial operation detected a hepatic lesion located at the site of the previous percutaneous transhepatic biliary drainage tract. Implantation of bile duct carcinoma in the drainage tract was diagnosed, and the recurrent tumor was successfully resected by performing a subsegmentectomy of segment 3 and removal of the adjacent abdominal wall. At present, 5 years and 4 months after the second resection, the patient is in good health without any signs of recurrence. This case report demonstrates that an aggressive surgical approach should be performed for tumor seeding of a transhepatic biliary catheter tract.

Carcinoma, Squamous Cell↗
PubMed1999

[Clinical results and complications of refractive surgery].

PURPOSE: To evaluate the efficacy of photorefractive keratectomy (PRK) with a scanning type excimer laser MEL-60 (AESCLUP-MEDITEC, Co). SUBJECTS AND METHOD: We performed PRK on 102 eyes of 62 myopic patients whose refraction ranged from-3.00 to -12.50 D (mean, -6.47 D) and examined the clinical results of postoperative refraction and complications. RESULTS: At 12, 18, and 24 months after the operation, the mean refraction was -1.57 +/- 1.25D, -1.63 +/- 1.51 D and -1.73 +/- 1.47 D. At 12 months after the operation, 36 eyes (46.2%) were within +/- 0.5 D of intended correction, 61 eyes (78.3%) within +/- 1.0 D, and 76 eyes (97.4%) within +/- 2.0 D. Twenty-four months after the operation, 12 eyes (37.5%) were within +/- 0.5 D, 18 eyes (56.3%) within +/- 1.0 D and 29 eyes (90.6%) within +/- 2.0 D. The complications were as follows: keratitis filamentosa was observed in 10 eyes (10.5%), decrease of contrast sensitivity in 7 eyes (7.4%), subepithelial corneal haze in 4 eyes (1.2%), steroid-induced glaucoma was 2 eyes (2.1%), increase of astigmatism in 2 eyes (2.1%), decrease of best corrected visual acuity in 2 eyes (2.1%), and corneal ulcer in 1 eyes (1.1%). CONCLUSION: PRK with a scanning type excimer laser MEL-60 was effective to reduce refractive error in low and mild myopia, but there were some complications, so that a long, careful follow-up seems necessary.

Adult↗
PubMed1999

[Immunosuppressive effect of cholera toxin B on allergic conjunctivitis model in the guinea pig].

PURPOSE: To investigate the immunosuppressive effects of mucosal immune therapy in experimental allergic conjunctivitis. METHOD: We used 11 white Hartrey guinea pigs divided into two groups. Six animals (treated group) received pretreatment with topical instillation of cholera toxin B (4 micrograms/30 ml) and ovalbumin (10 micrograms/30 ml). The other group of 5 animals served as control. All the animals received intraabdominal injection of ovalbumin (100 g/ml) and aluminium hydroxide (5 mg/ml) repeated twice 2 weeks apart. Allergic conjunctivitis was induced by topical instillation of ovalbumin solution (5 mg/ml) one week after the above procedure. RESULT: Both groups developed palpebral and bulbar edema with hyperemia 30 minutes after instillation. The allergic reaction was significantly less in score in the treated than in control group (Mann Whitney U-test: p < 0.01). The clinical findings subsiced after 6 hours. The treated group showed less eosinophilic infiltration in the conjunctiva and the limbus, particularly in the conjunctival and the limbus, particularly in the conjunctival epithelium, than in control group at 6 and 24 hours. CONCLUSION: Pretreatment with topical cholera toxin B and antigen suppresses clinical and histological findings in experimentally induced allergic conjunctivitis.

Animals↗
PubMed1998

Toward the antibody-catalyzed chemiluminescence. Design and synthesis of hapten.

Hapten 4 was synthesized to generate catalytic antibodies triggering chemiluminescence by catalyzing the decomposition of the 1,2-dioxetane 3. The hapten 4 was so designed as to elicit a negatively charged functional group in the antibody combining site to catalyze the beta-elimination of the protecting group in 3 as well as to lock the protecting group into an energetically favorable anti-periplanar conformation.

Antibodies, Catalytic↗
PubMed1998

Multiporous cellulose microcarrier for the development of a hybrid artificial liver using isolated hepatocytes.

BACKGROUND: This study was aimed at developing an optimal method for immobilizing isolated hepatocytes in cellulose multiporous microcarriers (MCs) and evaluating the metabolic activity of MC-immobilized hepatocytes. MATERIALS AND METHODS: Hepatocytes isolated from the livers of male Wistar rats were immobilized in collagen-coated MCs by intermittent stirring (30 rpm for 2 min per 15 min) for 180 min or accumulation methods. The accumulation method was performed by pouring aliquots of hepatocyte suspension (8 x 10(5)) and MC suspension (1 mg) in turn onto a nylon mesh (pore size: 100 micron). The metabolic activity of MC-immobilized hepatocytes in floating culture and in a newly developed bioreactor was evaluated. The metabolic activity of MC-immobilized hepatocytes in the bioreactor was also evaluated in in vitro perfusion of a hollow-fiber-based hybrid artificial liver support system. RESULTS: The accumulation method immobilized 20 times more hepatocytes in collagen-coated MCs than the intermittent stirring method (P < 0.01). Morphological observation of hepatocyte-immobilized MCs revealed that many hepatocytes were immobilized deep within the MCs maintaining a spherical shape and normal microvilli on their surface. MC-immobilized hepatocytes in floating culture revealed similar NH3 metabolism and glucose synthesis to monolayer-cultured hepatocytes, and this metabolic activity was maintained during 9h of floating culture. MC-immobilized hepatocytes in a bioreactor also showed similar NH3 metabolism to monolayer-cultured hepatocytes. The NH3 metabolism of MC-immobilized hepatocytes in in vitro perfusion of a hybrid artificial liver support system was 241.5 microg/h/mg protein/m2 membrane surface. CONCLUSIONS: The results of this study indicate that the accumulation method was optimal for immobilizing isolated rat hepatocytes in MCs and that MC-immobilized hepatocytes maintained their metabolic activity for a long period.

Ammonia↗
PubMed1998

Chorioretinal damage caused by the excision of choroidal neovascularization.

PURPOSE: To determine whether choroidal neovascularization excision causes mechanical damage to the neurosensory retina, retinal pigment epithelium, or choriocapillaris. METHODS: Prospectively, 18 eyes of 18 consecutive patients who underwent choroidal neovascularization excision were observed. Preoperatively and postoperatively, the integrity of the choriocapillaris circulation in the pathway of choroidal neovascularization extraction was studied by fluorescein and indocyanine green angiography. Using static scanning laser ophthalmoscope microperimetry, the presence of iatrogenic scotomas that developed postoperatively in the pathway of choroidal neovascularization extraction was also investigated. RESULTS: Postoperatively, a choriocapillaris defect was detected in 17 (94.4%) of 18 cases. In 15 cases (83.3%), the choriocapillaris defect had a clear relationship to the pathway of choroidal neovascularization extraction. Postoperatively, a scotoma was present in 16 (88.9%) of 18 cases. In 14 cases (77.8%), the location of the scotoma had a clear relationship to the pathway of choroidal neovascularization extraction. CONCLUSION: Surgical excision of choroidal neovascularization leads to severe damage of the choroid and retina in the pathway of the extracted choroidal neovascularization. The injury involves the neurosensory retina, retinal pigment epithelium, and choriocapillaris.

Adult↗
PubMed1998

[The effect of matrix metalloproteinase inhibitor on pseudomonal proteinases].

We examined the effect of CS-610, a newly developed matrix metalloproteinase (MMP) inhibitor, on pseudomonal proteinase in vitro. Alkaline proteinase (1143-4977 unit/ml Type I collagenase equivalent) and elastase (13.6-22.6 unit/ml Type I collagenase equivalent) were obtained from strains of P. aeruginosa of IID-1117, IID-1030 and IID-1130. Zymographic analysis of cultured broth of P. aeruginosa demonstrated that CS-610 inhibited alkaline proteinase with an IC50 (50% inhibition concentration) of 1.06-29.0 (x 10(-8)M) and elastase with an IC50 of 1.0-33.3 (x 10(-8)M). CS-610 is a potent inhibitor of pseudomonal proteinases.

Dose-Response Relationship, Drug↗
PubMed1998

[Clinical features of 10 cases with phlyctenular keratitis].

We investigated 15 eyes of 10 patients with phlyctenular keratitis. The patients were 6 men and 4 women, and their ages ranged between 3 and 56 years (mean, 17.8 years). The follow-up periods ranged from 0.5 to 48 months (mean, 14 months). Clinically, complications in many cases were papillary hyperplasia in palpebral conjunctiva, meibomian gland infarct, chalazion, and blepharitis. Microbial examination from the lid margin before treatment revealed bacteria in 4 eyes of 4 patients out of 9 eyes of 8 patients. The level of serum specific IgE antibody was high in only 1 patient out of 6. We classified the clinical course into 3 stages, namely, infiltrative, nodule, and cicatricial stages. We also investigated the transition of the disease among the stages. All the cases of the infiltrative stage progressed to the nodule stage, and 92% of the nodule stage went on to the cicatricial stage. However 14% of the cicatricial stage cases reverted to the infiltrative stage and 7% to the nodule stage.

Adolescent↗
PubMed1998

[A case of corneal abscess with impetigo contagiosa].

Impetigo contagiosa often occurs on the face of children. Although the eyelid and conjunctiva are frequently affected, no corneal involvement has been reported in Japan. We encountered a case of impetigo contagiosa with corneal abscess. The patient, an 8-year-old boy, complained of pain and presented with corneal abscess and iritis in the right eye as well as eruptions in the inferior eyelid and around the anterior nostrils. He was diagnosed as having impetigo contagiosa with corneal abscess. Because the corneal abscess and eruptions occurred at the same time and coagulase-positive Staphylococcus with identical drug sensitivity was isolated from both lesions, we considered the corneal lesion as a part of the impetigo contagiosa. When impetigo contagiosa occurs around the eye, especially on the eyelids, a careful examination of the anterior segment of the eye is needed.

Abscess↗
PubMed1998

Allogeneic hepatocyte transplantation: contribution of Fas-Fas ligand interaction to allogeneic hepatocyte rejection.

Hepatocyte transplantation is a potential therapeutic modality for overcoming the shortage of liver donors, and the clinical application of allogeneic hepatocyte transplantation has been considered. However, there are two major problems with allogeneic hepatocyte transplantation: protection of transplanted hepatocytes from rejection and stimulation of the rapid proliferation of surviving cells. Without immunosuppression, allogeneic hepatocytes are rapidly rejected within a few days after transplantation, even though it is relatively easy to induce immunotolerance after allogeneic whole liver transplantation. Accordingly, different rejection mechanisms seem to operate after allogeneic hepatocyte transplantation and whole liver transplantation. To overcome the rejection of transplanted hepatocytes, induction of donor-specific unresponsiveness to graft without compromising the host immune system would be ideal. We previously reported that the Fas-Fas ligand system plays a critical role in the CD28-independent pathway of hepatocyte rejection. Therefore, blockade of rejection using CTLA4 immunoglobulin (CTLA4Ig) or anti-CD80/86 monoclonal antibodies and anti-FasL monoclonal antibody may prolong the survival of transplanted allogeneic hepatocytes. Furthermore, administration of hepatocyte growth factor (HGF) can promote the proliferation of allogeneic hepatocytes and this may lead to the development of a functioning liver substitute.

Animals↗
PubMed1998

[Effect of matrix metalloproteinase inhibitor on experimental pseudomonal corneal ulceration].

We examined the effect of matrix metalloproteinase (MMP) inhibitor (CS-610) on experimental pseudomonal corneal ulceration by clinical and histological evaluation. Intrastromal injection of 3.5 microliters sterile culture broth of P. aeruginosa, IID-1117 (13.5 unit Type I collagenase equivalent proteinase activities), was done to induce corneal ulcers in guinea pigs. The animals were divided into two groups of 23 each. The CS-610 group received topical CS-610 (400 micrograms/ml) treatment at 2-hour intervals and the control group received only the vehicle of CS-610 at the same intervals. In the control group, corneas developed acute corneal damage following corneal ulcerations at 6-12 hours. In the CS-610 group, these corneal lesions were inhibited in most of the eyes (p < 0.01). In the late period, as inflammatory cells migrated into the cornea, some animals of the CS-610 group developed corneal ulcer. The results indicated that CS-610 had a potent inhibitory activity against pseudomonal proteinases in vivo. The results also suggested that the mechanism of the ulceration model involved not only pseudomonal proteinases but also endogenous responses.

Animals↗
PubMed1997

Enhancement of proliferation of intrasplenically transplanted hepatocytes in cirrhotic rats by hepatic stimulatory substance.

This study aimed at investigating the efficacy of hepatic stimulatory substance (HSS) on the proliferation of transplanted hepatocytes in the spleen of rats with carbon tetrachloride (CCl4)-induced liver cirrhosis. After hepatocyte transplantation (HTx; 1x10(7) cells/rat), the recipients received intravenous administration of HSS (3ml) of 2, 4, or 7 times/week to investigate the effect of the frequency of HSS treatment on the proliferation of intrasplenically transplanted hepatocytes. Next, to investigate the effect of the severity of liver cirrhosis on HSS-stimulated proliferation of transplanted hepatocytes, different doses (0.00, 0.08, 0.12, and 0.16 ml/week) of CCl4 were given to rats after HTx. The recipients were killed and the spleens were removed at 2 and 4 weeks after HTx and stained with bromodeoxyuridine (BrdU) and hematoxylin and eosin for determining the BrdU labeling index (L.I.) and the hepatocyte-occupied area ratio in the longitudinal cut surface of the spleen (H:S ratio), respectively. The H:S ratio was measured in the hematoxylin and eosin-stained splenic sections under a light microscope connected to an image processor. HSS-treated rats showed significantly higher BrdU L.I. and H:S ratios than the untreated control rats at 2 and 4 weeks after HTx. However, the difference in the BrdU L.I. and H:S ratio was not statistically significant among the HSS-treated rats. Without HSS treatment, the severity of liver cirrhosis did not affect the proliferation of intrasplenically transplanted hepatocytes. On the other hand, HSS-induced proliferation of transplanted hepatocytes was further enhanced in proportion to the severity of liver cirrhosis. The H:S ratio of the rats treated with 0.04, 0.08, and 0.16 ml/week of CCl4 after HTx was 1.27+/-0.5%, 4.32+/-0.65%, and 6.25+/-0.70%, respectively, at week 4. During the long-term observation of up to 12 weeks, a marked decrease in the H:S ratio was observed in HSS-untreated control rats at weeks 4-12 compared with week 2. While HSS-treated rats revealed gradual proliferation of intrasplenically transplanted hepatocytes, the difference in the H:S ratio between HSS-treated and -untreated rats became larger. These results indicate that HSS treatment of recipient rats stimulated the proliferation of intrasplenically transplanted hepatocytes in cirrhotic rats and that the severity of liver cirrhosis enhanced the stimulative effect of HSS on the proliferation of transplanted hepatocytes.

Animals↗
PubMed1997

Functional assessment of proliferating hepatocytes stimulated by hepatic stimulatory substance in ascorbic acid biosynthetic enzyme-deficient rats.

The functional ability of hepatic stimulatory substance (HSS)-stimulated proliferating hepatocytes was investigated by intrasplenic and/or intraportal transplantation in ascorbic acid (AsA) biosynthetic enzyme-deficient (ODS-od/od) rats that die of osteogenic disorders unless there is AsA supplementation. HSS was extracted from regenerating porcine livers. Hepatocytes isolated from the livers of congeneic ODS-+/+ rats that are capable of synthesizing AsA were transplanted into the spleen (Sp-HTx) and/or the portal vein (Pv-HTx) of ODS-od/od rats. The recipients were divided into eight groups as follows: HSS-untreated groups [group Ia, sham-operated, HTx(-); group IIa, Sp-HTx; group IIIa, Pv-HTx; and group IVa, Sp- and Pv-HTx], HSS-treated groups [group Ib, HSS only; group IIb, Sp-HTx + HSS; group IIIb, Pv-HTx + HSS; and group IVb, Sp- and Pv-HTx + HSS]. The recipients were given a diet and water containing AsA for 6 weeks after HTx, and AsA supplementation was then halted. The average bromodeoxyuridine (BrdU) labeling index (LI) and hepatocyte-occupied ratio in the spleen (H/S ratio) of HSS-treated rats were significantly higher than those of HSS-untreated rats. All the rats in HSS-untreated groups and group Ib died by 8 weeks after the cessation of AsA. In HSS-treated groups IIb, IIIb, and IVb, the survival rates were 60%, 50%, and 80%, respectively, at 16 weeks after HTx. The average serum AsA level of the surviving rats in groups IIb, IIIb, and IVb was significantly higher than that in HSS-untreated groups. These results indicate that HSS treatment induced rapid proliferation of transplanted hepatocytes in the spleen and the portal vein, and that these proliferating hepatocytes synthesized AsA and improved the survival rate of ODS-od/ od rats.

Animals↗
PubMed1997

Orthotopic transplantation of a partial hepatic autograft in dogs.

The purpose of this study was to investigate the availability of an orthotopic transplantation of partial hepatic autograft in dogs as a means of surgical training. Male mongrel dogs weighting 10-15 kg were used. The left lobe of the liver was harvested while preserving the left branches of the portal vein, hepatic artery and bile duct, and the left hepatic vein. The remnant liver was removed while preserving the inferior vena cava using a veno-venous bypass. Orthotopic transplantation of the autograft was performed while anastomosing the left hepatic vein to the inferior vena cava, portal and arterial reconstruction, and external biliary drainage. Thirteen out of 29 dogs survived more than 48 h after transplantation. However, 6 out of 13 dogs were sacrificed after developing bile peritonitis due to a dislodgement of the biliary catheter, and only two dogs were able to survive for 7 days after transplantation. The arterial ketone body ratio recovered to 1.0 within 1 h after reperfusion, and the ratio of the dogs that survived for more than 48 h remained above 1.0 until sacrifice. Orthotopic transplantation of a partial hepatic autograft is a useful and simple procedure to train surgeons for partial liver transplantation.

Animals↗