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Biomedical subjects

M Sawa

Publications and source records attributed to M Sawa.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Anterior chamber inflammation after cataract intraocular lens surgery in postvitrectomy eyes].

We determined the anterior chamber inflammation by means of laser flaremetry after cataract intraocular lens surgery for the nuclear cataract that developed after vitrectomy. Cases (38 eyes of 36 patients) were divided into the following four groups according to their pathologies indicating vitrectomy; proliferative diabetic retinopathy (PDR, 14 eyes), idiopathic posterior vitreous membrane syndrome (PVMS, 9 eyes), rhegmatogenous retinal detachment (RRD, 8 eyes), and branch retinal vein occlusion (BRVO, 7 eyes). Mean intervals between the two surgeries were 31, 23, 27 and 18 months, respectively. Phacoemulsification and aspiration through the self-sealing sclerocorneal wound and intraocular lens implantation in the bag were performed. The mean flare count was already high before the cataract surgery in all groups. Postoperative course of mean flare count was an overlap of two waves, one (P1) with a peak on day 1 followed by rapid decrease and the other (P7) with a peak on day 7 followed by slow decrease. Peak values of P1 were higher than the day 1 value after cataract surgery without fundus pathology, and higher in PDR and BRVO groups than in PVMS and RRD groups. P7 was like that observed after vitrectomy and there was close similarity among the groups.

Aged↗
PubMed1995

Circadian rhythms in aqueous protein concentration and intraocular pressure in rabbits.

Circadian rhythms in aqueous protein concentration (APC) and intraocular pressure (IOP) were examined in Dutch rabbits using the laser flare-cell meter and a pneumatonometer. The reproducibility and seasonal changes in circadian rhythm were also investigated. Rabbits were trained to a lighting cycle of 12-hour light and 12-hour darkness. The mean value of reproducibility coefficients obtained with re-examination at 2-week intervals was 21.9% in the reading of the laser flare-cell meter. APC was reduced during the dark phase, and increased rapidly and remained high during the light phase. On the other hand, IOP showed an inverse circadian rhythm which was negatively correlated with that of APC. The total average of APC throughout 24 hours was 39.1 +/- 28.3 (mean +/- SD) mg/100 ml equivalent of bovine serum albumin, which agreed with the previous data. Seasonal changes in circadian rhythm were not statistically significant either in APC or in IOP.

Animals↗
PubMed1995

[Distribution of S-100 protein positive cells in conjunctiva].

We compared the distribution of S-100 protein positive cells in normal conjunctiva and in an induced allergic conjunctivitis model using Hartley strain guinea pigs. The animals were sensitized by intraperitoneal injection of ovoalbumin solution with hydroxy aluminum, followed by topical application of the ovoalbumin solution. The primary antibody was antibovine brain S-100 positive antibody, detected by the avidin biotin complex method. S-100 positive cells were present at the limbal corneal epithelium and on the skin of the palpebrae in both the normal group and the allergic conjunctivitis group, indicating the presence of Langerhans cells. In the allergic group, positive cells were also detected in palpebral conjunctiva and the germinal centers of conjunctival follicles. These cells were identified as follicular dendritic cells or interdigitating cells. In conclusion antigen presenting cells were present in the limbal conjunctiva, follicular and parafollicular area of conjunctival follicles, and palpebral skin in the allergic conjunctivitis models.

Animals↗
PubMed1995

[Effect of a newly developed corneal storage medium on corneal endothelium--morphological study by scanning electron microscopy].

We compared the effects on corneal endothelium of the new storage mediums I and II with those of OPTISOL. Storage mediums I and II had the same formula, i.e., 0.1% hyaluronic acid, except for the concentration of basic medium TC-199. I contained 70% of the TC-199 concentration of OPTISOL and II contained 80%. Rabbit corneas were stored in storage mediums I and II for 3, 7, 10 and 14 days and in OPTISOL for 7, 10 and 14 days at 4 degrees C. After the 3-day storage period, endothelial cells were preserved in good condition. After the 7-day storage period, medium I showed better preservative ability in endothelial configuration than the other two storage media. Medium II and OPTISOL showed a similar storage potential morphologically. With increasing storage time, endothelial cells showed an irregular surface and a less defined cellular edge in both media II and OPTISOL.

Animals↗
PubMed1995

[A morphological study of lymphocyte homing in conjunctiva-associated lymphoid tissue].

High endothelial venule (HEV) is an important component of the mucosa-associated lymphoid tissue and plays a role in the homing phenomenon of lymphocytes. We investigated the presence of HEVs in conjunctiva-associated lymphoid tissue (CALT) using guinea pigs sensitized with ovalbumin. Electron microscopy showed characteristic findings for HEVs in the parafollicular area of the CALT. Lymphocytes in the vessels are trapped not only by microprocesses extending from the vascular endothelium but also by the endothelial cells. Some endothelial cells also appear to release lymphocytes. We conclude that HEVs are present also in the CALT.

Animals↗
PubMed1994

Lens accommodation evoked by microstimulation of the superior colliculus in the cat.

Accommodative responses to microstimulation of the superior colliculus (SC) of cats were investigated by measuring dioptric changes of the eye with a high-speed infrared optometer. Lens accommodation was elicited by low-current stimuli (< or = 20 microA) of the rostral portion of the SC, which corresponds to the representation of the central visual field. The low-threshold area for evoking lens accommodation was distributed from the superficial to intermediate layers of the SC. The latency of accommodative responses was 198.3 +/- 34.6 msec (mean and SD). The duration of accommodation was highly correlated with the duration of stimulation. These findings suggest that the SC plays an important role in the control of lens accommodation.

Accommodation, Ocular↗
PubMed1994

Is the biological artificial liver clinically applicable? A historic review of biological artificial liver support systems.

Hemoperfusion, hemodiafiltration, plasma exchange, and extracorporeal liver perfusion have already been adopted to treat patients with acute and chronic hepatic failure. However, the survival rate of patients with acute hepatic failure remains at approximately 30% and has not improved as expected. Current advances in biotechnology have opened the way for the development of a biological artificial liver, which is called the hybrid artificial liver because it consists of both biological and artificial materials. Isolated hepatocytes have been investigated for use in various types of hybrid artificial liver. In addition, the role of biomatrices, microcarriers, and the microencapsulation technique has been studied with respect to long-term maintenance of hepatocellular function and development of high-density culture systems for hepatocytes. Before clinical application of hybrid artificial liver support systems becomes possible, many problems have to be resolved, including large-scale preparation and long-term preservation of biomaterials, high-density and stable immobilization of biomaterials on artificial materials, control of immunological hazards, biocompatibility, safe transportation and sterilization of biomaterials, and the high cost. We review the history of biological artificial livers and discuss their future role.

Animals↗
PubMed1994

Collagenase activity and tissue inhibitor of metalloproteinases-1 (TIMP-1) content in human whole saliva from clinically healthy and periodontally diseased subjects.

Total TIMP-1 concentration in whole saliva of periodontally diseased subjects, 137 +/- 67 ng/ml (mean +/- SD), was clearly lower (p < 0.001) than that of clinically healthy subjects, 273 +/- 145, and that of edentulous subjects, 332 +/- 121. On the contrary, both active [1.58 +/- 0.35 units/ml (mean +/- SD)] and total (2.08 +/- 0.25) collagenase activities in TIMP-1-free whole saliva of diseased subjects were significantly higher than the activities (0.14 +/- 0.14 and 0.50 +/- 0.27, respectively) in TIMP-1-free whole saliva of healthy subjects. Most of the total collagenase in whole saliva of healthy subjects consisted of procollagenase, while mainly active collagenase was present in whole saliva from patients with periodontal diseases. Significant reciprocal changes of TIMP-1 and collagenase levels, that is, increase in TIMP-1 concentration and decrease in collagenase activity, were observed after the initial therapy of periodontitis patients.

Adolescent↗
PubMed1994

Detection of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus in donor eyes using polymerase chain reaction.

Detection of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) in donor eyes was performed. DNAs were extracted from the uvea, and they were amplified using the polymerase chain reaction (PCR). Amplified viral DNAs were detected with liquid hybridisation and chemiluminescent assay in which no radioactive materials were used. This method was shown to have a sensitivity limit of fewer than 10 copies of HIV, making it much more sensitive than the current techniques employed in eye banks. The method was applied to 120 donor eyes, including four from donors seropositive for HBV. The HBV gene was detected in one case in which the donor's blood had not been tested for HBV. HIV and HCV genes were not detected in any of the samples. The assay could be an effective screening test for the detection of these viruses in eye bank eyes.

Adolescent↗
PubMed1994

[Quantitative analysis of glycosaminoglycans in tear fluids during corneal epithelial wound healing in rabbits].

We performed quantitative analyses of glycosaminoglycans in the tear fluids in a rabbit wound healing model. We ablated rabbit corneal epithelium with trephine and spatula, and sampled tear fluids before the epithelial ablation, and at 3, 24, 48, and 72 hours after it. After an instillation of 200 microliters saline solution in the conjunctival sac, as much tear fluid as possible was collected from the lower cul-del-sac. The glycosaminoglycans in the tears were then treated with chondoroitinase ABC to make fractions of disaccharides. The quantities of disaccharides were determined with high-performance liquid chromatography as weight per unit protein in the tears. The concentrations of delta Di-HA in the tear fluids at 3 and 24 hours were significantly higher than those before the treatment and returned to the initial value at 72 hours after making the epithelial wound. Among the disaccharides of chondroitin sulfate, delta Di-0S and delta Di-6S showed a significant increase at 3 hours after the treatment but delta Di-4S did not show any significant variation. The results suggest that the glycosaminoglycans in the rabbit tear fluids may play an important role in the corneal epithelial wound healing process.

Animals↗
PubMed1994

[Spectral transmittance of normal human crystalline lens].

The spectral transmittance and non-tryptophan fluorescence of human crystalline lenses were evaluated. Eleven eye bank lenses and three lenses of prematurity of retinopathy patients were investigated. All lenses absorbed the short wavelength light below 430 nm strongly. The transmission of the short wavelength visible light decreased gradually with age. There was a positive correlation between the fluorescence intensity ratio of non-tryptophan to tryptophan fluorescence and the logarithm of age. It was thought that the generation of non-tryptophan fluorescence might be a first-order chemical reaction.

Adult↗
PubMed1994

Effect of MK-507 on aqueous humor dynamics in normal human eyes.

The effects of the topical carbonic anhydrase inhibitor, MK-507, on aqueous humor dynamics were studied in 6 normal volunteers. As a baseline study, intraocular pressure (IOP) was determined and aqueous protein concentration was checked hourly by laser flare-cell photometry from 0900 to 1800 hours. One week later, IOP and aqueous protein concentration were determined in the same subjects on the same time schedule with instillation of 1% MK-507 at 1100 hours. After one more week, the same experiment was carried out with oral administration of acetazolamide at a dose of 250 mg at 1100 hours. Topical MK-507 showed the maximum IOP reduction at 3 hours and increased aqueous protein concentration reaching its maximum at 4 hours. Oral acetazolamide showed the maximum IOP reduction at 2 hours and the maximum increase in aqueous protein concentration was at 3 hours. Although the peak effect on IOP or aqueous protein concentration did not significantly differ between topical MK-507 and oral acetazolamide, only oral acetazolamide showed a significant effect at 1 hour. These results suggested that topical MK-507 reduced the aqueous humor production, but it took more time for the ocular effect to become manifest than after administration of oral acetazolamide.

Acetazolamide↗
PubMed1994

[Effect of topical carbonic anhydrase inhibitor (MK-507) on intraocular pressure of normal human eyes].

The effects of topical carbonic anhydrase inhibitor (MK-507) on intraocular pressure (IOP) were studied in normal human eyes. The subjects were 6 normal volunteers. As a base line study, IOP and aqueous protein concentration determined by laser flare-cell photometry were examined from 0900 to 1800 hours. Then, the same time-course examinations were performed in the same subjects with an instillation of 1% MK-507 or administration of acetazolamide at a dose of 250 mg on different days. MK-507 decreased IOP 2 hours after the instillation, and showed maximum reduction of IOP at 3 hours. MK-507 increased aqueous protein concentration 2 hours after the instillation, and reached its maximum concentration at 4 hours. Acetazolamide decreased IOP and increased aqueous protein concentration 1 hours after the administration. Maximum decrease of IOP was obtained at 1 hour after the administration of acetazolamide. An increase in aqueous protein concentration occurred at 1 hour after the administration, but its maximum increase was at 3 hours. Corneal thickness, anterior chamber depth, anterior chamber volume, and serum protein concentration were not affected by either drug treatment. These results suggest that the inhibition of aqueous humor formation causes the reduction of IOP seen in the use of MK-507.

Acetazolamide↗
PubMed1993

Inherited amyloid polyneuropathy type IV (gelsolin variant) in a Japanese family.

We describe a Japanese family with familial amyloid polyneuropathy type IV. The family originates from central Japan, Nagano prefecture, and is unrelated to Finnish or other Caucasian populations. Of 42 members in three generations, 14 individuals (5 men, 9 women) are affected by corneal lattice dystrophy, cranial neuropathy, mild peripheral neuropathy, and skin changes. Polarizing microscopy and immunohistochemistry studies of skin biopsy samples demonstrated abundant amyloid deposits, which bound an antigelsolin monoclonal antibody. Direct sequence analysis of a DNA fragment spanning codon 187 of plasma gelsolin complementary DNA and restriction analysis using a modified polymerase chain reaction demonstrated a single base substitution, guanine to adenine, at nucleotide position 654, which is identical to the mutation in Finnish familial amyloid polyneuropathy type IV. This strongly suggests that the mutation causes the familial amyloid polyneuropathy type IV phenotype regardless of ethnic background.

Adult↗
PubMed1993

Genetics and biology of the sawfly, Athalia rosae (Hymenoptera). Review.

Hymenopteran insects are a unique group of animals in which arrhenotokous reproduction (haploid males develop from unfertilized eggs) is a rule. Males produce sperm through a non-reductional maturation division. A sawfly species, Athalia rosae ruficornis Jakovlev Tenthredinidae, Symphyta, Hymenoptera) has introduced as a new experimental material for studies on genetics and developmental biology. Basic features relating to the potential usefulness of the species in elucidating some to the important genetic and developmental biological problems are described.

Amino Acid Sequence↗
PubMed1993

Convergence paralysis after lesions of the cerebellar peduncles.

We studied vergence eye movements in a patient with limited hemorrhage affecting the right cerebellar peduncles and the hemisphere. The patient showed exotropia of 30 prism dptr during near vision. Some vergence paradigms were investigated in this patient. We studied fusional vergence evoked by placing a wedge prism before one eye. Accommodative vergence was studied by blur stimulus using a servocontrolled optometer. Lens accommodation was also recorded during blur stimulus. Although accommodative responses were normal, accommodative vergence was almost absent as well as fusional convergence in this patient. It has previously been reported that the cerebellum has a role in the control of vergence in the monkey. Our data suggest that the human cerebellum also relates to the control of vergence.

Accommodation, Ocular↗