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Biomedical subjects

A Tawara

Publications and source records attributed to A Tawara.

At least 19 recordsLinked to original sources
PubMed2001

Influence of TT virus on the clinical course of alcoholic liver disease.

The sera of 43 patients with alcoholic liver disease (ALD) who abstained from alcohol for 4 weeks, were tested for TT virus (TTV) DNA by polymerase chain reaction (PCR) using three different primer pairs (UTR PCR, N22 PCR and genotype-1 PCR). The clinical course of the TTV DNA-positive and -negative groups was compared. By UTR PCR which detects all TTV genotypes, TTV DNA was detected in 40 patients (93%). N22 PCR which detects primarily TTV genotypes 1-6, detected TTV DNA in 17 patients (40%). The alanine aminotransferase (ALT) level 4 weeks after the start of abstinence was significantly higher and the rate of change in ALT {[(ALT on admission-ALT 4 weeks after abstinence)/(ALT on admission)]x100} was lower in the patients who were positive by N22 PCR, than in those who were negative by N22 PCR. Twelve patients (28%) were positive for TTV genotype 1. In the TTV genotype 1-positive group, the ALT 4 weeks after the start of abstinence was significantly higher, and the improvement rates of ALT, gamma-glutamyl transpeptidase and alkaline phosphatase levels were lower than those in the TTV genotype 1-negative group. These results suggest that certain genotypes of TTV may interfere with the improvement of liver function following the start of abstinence in ALD patients.

Journal Article↗
PubMed2001

[Apparent size of stereoscopic images with disparity in relation to the function of accommodation].

PURPOSE: We investigated experimentally the relationship between the apparent size of stereoscopic images with disparity and the accommodative function. METHODS: The judgement of the apparent stereoscopic image size used the subject reply. The size of the forward image, which was produced by crossed visual lines with binocular disparity and by a time-sharing type stereoscopic three-dimensional display using liquid crystal shutter glasses, was compared with the size of the plane image. The size of the backward image produced by uncrossed visual lines was also compared with the size of the plane image. Sixteen normal volunteers were requested to subjectively compare each image with the original plane image on the display screen in relation to its size. Accommodation was measured using an infrared optometer to record the step responses (from far to near, and near to far). The subjects were divided into two groups, a fast response group and slow response group. RESULTS: It was found that the forward image was smaller than the plane image and the backward image was larger than the plane image, and this tendency was remarkable in the fast response group. CONCLUSION: From these results, it appears that the state of accommodation affects the perceived size of stereoscopic images with disparity.

Accommodation, Ocular↗
PubMed2000

TT virus mRNAs detected in the bone marrow cells from an infected individual.

Although replicative forms of TT virus (TTV) DNA have been found in the liver and bone marrow cells, mRNAs of TTV have not yet been detected in these tissues. The entire nucleotide sequence of a TTV clone [TYM9 (3759 bases)] isolated from a patient with high TTV viremia (10(6) copies/ml) was determined, and the poly(A)(+) RNAs from bone marrow cells were subjected to reverse transcription-polymerase chain reaction with primers specific for the TYM9 sequence. Sequence analysis of the amplified products revealed the presence of three distinct species of spliced TTV mRNAs [2.9, 1.2, and 1.0 kilobases (kb)] with common 5' and 3' termini as well as splicing to bind nucleotide (nt) 181 to nt 283. The shorter mRNAs of 1.2 kb and 1.0 kb possessed another splicing to join nt 681 with nt 2341 or nt 2579. The transcription profile of TTV found in an infected human corroborates that observed in vitro.

3' Untranslated Regions↗
PubMed2000

Species-specific TT viruses in humans and nonhuman primates and their phylogenetic relatedness.

By means of polymerase chain reaction with a primer pair (NG133-NG147) deduced from the untranslated region (UTR) of TT virus (TTV), TTVs with markedly distinct genomic lengths were recovered from sera of humans and nonhuman primates, and their entire nucleotide sequences were determined. A human TTV [TGP96 of 2908 nucleotides (nt)] was obtained that was about 900 nt shorter than heretofore reported TTVs (3787-3853 nt). Likewise, TTVs of chimpanzee occurred in two distinct genomic sizes [Pt-TTV6 (3690 nt) and Pt-TTV8-II (2785 nt)]. Two TTVs of Japanese macaque [Mf-TTV3 (3798 nt) and Mf-TTV9 (3763 nt)] were comparable in genomic length, but only 55% similar in sequence. These five human and nonhuman primate TTVs, along with TTVs of tamarin [So-TTV2 (3371 nt)] and douroucouli [At-TTV3 (3718 nt)], were compared over the entire nucleotide sequence. Although the seven TTVs were only < or = 55% similar, they share a common genomic organization with two open reading frames (ORFs), designated ORF1 (654-735 amino acids) and ORF2 (91-152 amino acids). The N-terminal sequences of ORF1 proteins were rich in arginine, and sequence motifs necessary for transcription and replication were conserved among them all. Like the human prototype TTV (TA278), all seven TTVs from various animals possessed in common two 15-nt sequences (CGAATGGCTGAGTTT and AGGGGCAATTCGGGC) in the UTR that were covered by NG133 and NG147, respectively. These primers would be instrumental in research on TTVs in previously unexamined species for defining their virological characteristics and evolutionary relationships.

Amino Acid Sequence↗
PubMed2000

Transmission of human TT virus of genotype 1a to chimpanzees with fecal supernatant or serum from patients with acute TTV infection.

Fecal supernatant or serum containing TT virus (TTV) of genotype 1a (10(5) copies/ml) from patients with acute TTV infection was inoculated intravenously into two naive chimpanzees. Serum samples were obtained weekly and tested for TTV DNA by genotype 1-specific polymerase chain reaction. TTV DNA was detected in chimpanzee 228 at weeks 5-15 after inoculation with 0.5 ml of serum, and in chimpanzee 234 at weeks 7-19 after inoculation with 1 ml of fecal supernatant. The TTV DNA titer peaked at weeks 12 and 13 in chimpanzee 228 and at weeks 14-16 in chimpanzee 234. Mild biochemical and histological changes in biopsied liver samples were observed in both chimpanzees in association with the reduction in TTV titer. TTV DNA was transient in chimpanzee 228, but in chimpanzee 234 it reappeared at week 21 and persisted through week 30. These results indicate that TTV in feces is infectious and suggest that TTV has hepatitis-inducing capacity.

Acute Disease↗
PubMed2000

Replicative forms of TT virus DNA in bone marrow cells.

TT virus (TTV) is a human virus consisting of a single-stranded, circular DNA genome of 3.8 kilobases (kb). To examine whether TTV replicates in peripheral blood mononuclear cells (PBMCs) and bone marrow cells (BMCs), DNA was extracted from the PBMCs and/or BMCs of six TTV-infected individuals and separated by agarose gel electrophoresis. The TTV DNAs from the PBMCs migrated to the 2.0- to 2.5-kb region. The TTV DNAs from the BMCs migrated to the 2.0- to 2. 5-kb and 3.3- to 6.1-kb regions. The faster-migrating TTV DNAs were sensitive to S1 nuclease, while the slower-migrating TTV DNAs were resistant and their position on the agarose gel shifted to the position of the full genomic size upon digestion with restriction enzyme PstI. Full-length inverted polymerase chain reaction on the slower-migrating, double-stranded TTV DNAs from the BMCs amplified a 3.8-kb product. Replicative intermediate forms of TTV DNA are present in BMCs but not in PBMCs.

Base Sequence↗
PubMed2000

[Intraocular pressure during hemodialysis].

Hemodialysis, a useful treatment for patients with severely compromised renal function, has also unfavorable side effects. In the ophthalmologic area, a rise in intraocular pressure (IOP) during dialysis accompanied by ocular pain has been reported. In our study when measuring IOP, as well as serum osmolality and plasma CO2 pressure every 30 minutes during routine hemodialysis in renal failure patients with a normal aqueous outflow facility, the mean percent changes of IOP to the initial value showed no significant difference at any time, although the changes in serum osmolality decreased significantly. The mean percent changes of plasma CO2 pressure also did not show any significant difference during dialysis. In patients with a poor aqueous outflow facility, the mean percent changes of IOP increased significantly after 90 minutes, with the exception of the change at 180 minutes. The mean percent changes of serum osmolality decreased significantly after starting dialysis. A negative correlation in the mean percent change of IOP with that of serum osmolality was detected. The administration of an intravenous hyperosmotic agent prevented significant changes not only in serum osmolality but also in IOP. Therefore, it is considered that hemodialysis causes a decrease in serum osmolality, resulting in an osmotic gradient between the plasma and the intraocular fluids due to the presence of the blood-ocular barrier. Although the osmotic gradient draws water from the plasma into the eye, if there is no abnormal obstruction in the aqueous outflow pathway, an amount of aqueous humor matching the increase in intraocular fluid goes through the pathway out of the eye to maintain the normal level of IOP. In eyes with an obstructed aqueous outflow pathway, however, this compensatory mechanism of aqueous humor drainage does not work well, and results in an IOP elevation.

Aqueous Humor↗
PubMed2000

The entire nucleotide sequences of two distinct TT virus (TTV) isolates (TJN01 and TJN02) remotely related to the original TTV isolates.

TT virus (TTV) has a wide range of sequence divergence by which it is classified into at least 16 genotypes. A TTV isolate of genotype 12 (TJNO1) and another of genotype 13 (TJN02) were sequenced in the entire genome, and compared with the reported TTV isolates. TJN01 and TJN02 had genomic lengths of 3787 and 3794 nucleotides (nt), respectively, which were shorter by 66 and 59 nt than the prototype TTV isolate of genotype 1 (TA278). TJN01 and TJN02 shared the nucleotide sequence with TA278 merely in 53.9% and 55.2%, respectively. They possessed two major open reading frames (ORFs) and the noncoding region with a GC-rich region forming stem-loop structures, which are characteristic of TTV. However, their amino acid sequences in ORF1 were similar to that of TA278 in only 35.4 and 34.0%, respectively; TJN01 was 45.4% similar to TJN02. Comparison with TTV isolates of the same genotype identified hypervariable regions in ORF1 of TJN01 and TJN02, as in the prototype TTV of genotype 1. However, quasispecies were barely observed in them. Furthermore, sequences of hypervariable regions scarcely changed during 2-5.5 years in both TJN01 and TJN02. These results indicate that TTV of genotypes 12 and 13 are much different from the prototype TTV of genotype 1.

Adolescent↗
PubMed2000

Immunohistochemical localization of MYOC/TIGR protein in the trabecular tissue of normal and glaucomatous eyes.

PURPOSE: To examine immunohistochemically the localization of myocilin/trabecular meshwork inducible glucocorticoid response (MYOC/TIGR) protein in the glaucomatous and normal trabecular meshworks. METHODS: Trabecular tissues were used from one eye with late-onset goniodysgenetic glaucoma, three with primary open angle glaucoma (one of which had the MYOC/TIGR gene mutation), two with exfoliation glaucoma and one without glaucoma. For light microscopic immunohistochemistry, frozen sections were stained by the avidin-biotin complex method using anti-MYOC/TIGR polyclonal antibody. For electron microscopic immunohistochemistry, the pre-embedding method using the same antibody was performed. Double immunostaining using both anti-MYOC/TIGR and anti-type VI collagen antibodies was done by the immunofluorescence method. RESULTS: With light microscopy, immunoreactivity was seen in the whole trabecular meshwork of each of the specimens. No notable differences were detected in staining among the types of glaucoma, or between the eyes with and those without the gene mutation. Under electron microscopy, immunoreaction products were observed not only in the cytoplasm of the trabecular cells but also in the extracellular matrix, where staining was associated with the long-spacing collagen, fine granular materials and possibly microfibrils. With double immunohistochemistry, MYOC/TIGR was colocalized with type VI collagen in the trabecular meshwork. CONCLUSIONS: In glaucomatous and normal trabecular meshworks, the MYOC/TIGR protein is distributed in the extracellular matrix colocalizing with type VI collagen.

Adolescent↗
PubMed2000

Species-specific TT viruses and cross-species infection in nonhuman primates.

Viruses resembling human TT virus (TTV) were searched for in sera from nonhuman primates by PCR with primers deduced from well-conserved areas in the untranslated region. TTV DNA was detected in 102 (98%) of 104 chimpanzees, 9 (90%) of 10 Japanese macaques, 4 (100%) of 4 red-bellied tamarins, 5 (83%) of 6 cotton-top tamarins, and 5 (100%) of 5 douroucoulis tested. Analysis of the amplification products of 90 to 106 nucleotides revealed TTV DNA sequences specific for each species, with a decreasing similarity to human TTV in the order of chimpanzee, Japanese macaque, and tamarin/douroucouli TTVs. Full-length viral sequences were amplified by PCR with inverted nested primers deduced from the untranslated region of TTV DNA from each species. All animal TTVs were found to be circular with a genomic length at 3.5 to 3.8 kb, which was comparable to or slightly shorter than human TTV. Sequences closely similar to human TTV were determined by PCR with primers deduced from a coding region (N22 region) and were detected in 49 (47%) of the 104 chimpanzees; they were not found in any animals of the other species. Sequence analysis of the N22 region (222 to 225 nucleotides) of chimpanzee TTV DNAs disclosed four genetic groups that differed by 36.1 to 50.2% from one another; they were 35.0 to 52.8% divergent from any of the 16 genotypes of human TTV. Of the 104 chimpanzees, only 1 was viremic with human TTV of genotype 1a. It was among the 53 chimpanzees which had been used in transmission experiments with human hepatitis viruses. Antibody to TTV of genotype 1a was detected significantly more frequently in the chimpanzees that had been used in transmission experiments than in those that had not (8 of 28 [29%] and 3 of 35 [9%], respectively; P = 0.038). These results indicate that species-specific TTVs are prevalent in nonhuman primates and that human TTV can cross-infect chimpanzees.

Animals↗
PubMed1999

Histopathological changes in iridocorneal angle of inherited glaucoma in rabbits.

BACKGROUND: We examined morphologically the angular region of eyes affected by inherited glaucoma in rabbits genetically developed by crossbreeding in order to investigate the etiologic changes in the iridocorneal angle and to establish whether this strain of rabbit is a suitable animal model of goniodysgenetic glaucoma in humans. METHODS: The angular regions of both normal and glaucomatous eyes from four rabbits having unilateral inherited glaucoma were observed with light and electron microscopy. RESULTS: In the glaucomatous eyes angular region, the aqueous plexus corresponding to Schlemm's canal in humans was open and located far peripherally to the peripheral margin of the anterior chamber angle, although the plexus of one glaucomatous eye was poorly developed with a small lumen. In the angular meshwork, which corresponds to the trabecular meshwork in humans, a thick abnormal tissue with round cells embedded in the extracellular matrix was located just beneath the plexus. A large amount of extracellular matrix of basal lamina-like material was observed in the thick tissue. In the normal eyes, the angular region consisted of well-developed trabecular sheets with neither a thick tissue nor accumulations of extracellular matrix in the angular meshwork. CONCLUSION: The findings observed in the glaucomatous eyes are much the same as those observed in goniodysgenetic glaucoma in humans, suggesting that this strain of inherited glaucoma rabbits is a suitable animal model of goniodysgenetic glaucoma in humans. The present study also supports the hypothesis that the presence of a thick subcanalicular tissue due to maldevelopment of the iridocorneal angle is one of the main causes of this type of glaucoma.

Animals↗
PubMed1999

Postmortem findings two weeks after oral treatment for metastatic Candida endophthalmitis with fluconazole.

The purpose of this histological study was to present postmortem findings in both eyes of a 53-year-old male with liver dysfunction 2 weeks after short-time oral treatment with 200 mg/day fluconazole for metastatic Candida endophthalmitis due to intravenous hyperalimentation for 18 days. Candida had been demonstrated in the venous blood and on the tip of the intravenous catheter. The bilateral fungal endophthalmitis with hypopyon responded well to fungistatic therapy, but the patient suddenly died from heart failure. Both eyes were obtained at autopsy. Candida was demonstrated only in vitreous puff balls but not in the retina or uvea. Fluconazole administered for a short period had little effect in eliminating fungus from vitreous puff balls, which have no blood supply. Prolonged administration of the antifungal drug or vitrectomy should be considered when treating an eye with vitreous puff balls in the presence of fungal endophthalmitis.

Administration, Oral↗
PubMed1999

[Iris vessel involvement in iris-nevus syndrome].

PURPOSE: To report a case of iris-nevus syndrome accompanied by disruption of the blood-aqueous barrier in the iris which was confirmed angiographically and histopathologically. CASE: The patient was a 39-year-old woman. She noticed blurred vision in the left eye which was diagnosed as left glaucoma. Specular microscopy revealed low endothelial cell density in the left cornea. The left iris showed atrophy with clusters of nodular iris nevus and distorted pupil. The left iridocorneal angle was closed with peripheral anterior synechia. FINDINGS: Indocyanine green iris angiography revealed more vessels on the surface of the left iris than on the right. In fluorescein iris angiography, the dye leaked from the iris vessels in areas where the iris showed advanced atrophy. The trabecular tissue obtained by trabeculectomy from the patient's left eye showed histopathologically a lining of corneal endothelial cells on the surface of the iris. The density of the vessels was high in the iris stroma. Some cells covering the vessel wall showed degeneration with opening of the zonula occludens. Schlemm's canal had narrowed lumina, and the intertrabecular spaces were closed. CONCLUSION: Disruption of the blood-aqueous barrier may occur in iris-nevus syndrome.

Adult↗
PubMed1998

Double staining of proteoglycans and the HNK-1 carbohydrate epitope in pseudoexfoliation material.

PURPOSE: We combined the techniques of both immunogold and cupromeronic-blue staining with electron microscopy to investigate the possible relationship between proteoglycans and the HNK-1 carbohydrate epitope in pseudoexfoliation material. METHODS: The anterior segment was obtained from an enucleated eye with pseudoexfoliation syndrome. After cupromeronic-blue staining, following the method of Scott, specimens were embedded in L. R. White resin. Ultrathin sections were incubated successively in primary monoclonal antibodies, and 10 nm gold-conjugated secondary antibody. RESULTS: The present study showed simultaneous presence of the HNK-1 epitope and proteoglycans associated with zonular fibrils and pseudoexfoliation material on the posterior surface of the iris. The HNK-1 epitope was immunolocalized to the periphery of the pseudoexfoliation fibers, while cupromeronic blue-positive filaments bridged adjacent pseudoexfoliation fibers. CONCLUSIONS: Proteoglycans and the HNK-1 epitope might play a substantial role in the formation of pseudoexfoliation material via their adhesive function. Proteoglycans probably do not directly bear the HNK-1 epitope in pseudoexfoliation material.

Aged↗
PubMed1998

Ultrastructural examination of corneal epithelium of spontaneously obese, hyperglycemic rats.

PURPOSE: Otsuka Long-Evans Tokushima fatty (OLETF) rats spontaneously become obese and hyperglycemic with age. We investigated whether the development of hyperglycemia would alter the ultrastructure of the corneal epithelium. METHODS: Scanning and transmission electron microscopy (SEM and TEM) were used to examine the morphology of corneal epithelial cells. Fourteen OLETF rats were evaluated, and 9 Long-Evans Tokushima Otsuka (LETO) rats were used as control. Non-hyperglycemic OLETF rats served as controls. RESULTS: SEM showed exfoliative changes in the surface of the central corneal epithelium of the hyperglycemic OLETF rats. These superficial epithelial cells were irregular in shape as compared to polygonal shapes of those of LETO and non-hyperglycemic OLETF rats. The mean anterior surface area of individual superficial epithelial cells was significantly smaller in the hyperglycemic OLETF than that of the LETO or the non-hyperglycemic OLETF rats. Central protrusion(s) could be found in some of the superficial cells of all rats examined, although this phenomenon was more common in the hyperglycemic rats than in the non-hyperglycemic rats. TEM revealed that there were numerous cytoplasmic vacuoles and wide intercellular spaces in the central corneal epithelium of the hyperglycemic OLETF rats, but not in the non-hyperglycemic rats. CONCLUSIONS: The development of spontaneous hyperglycemia in OLETF rats alters the ultrastructure of the corneal epithelium. The alterations included abnormalities of the corneal epithelial surface observed by SEM and the presence of intracellular vacuoles and enlarged intercellular spaces detected by TEM.

Animals↗
PubMed1998

Early changes in iris blood vessels in exfoliation syndrome.

PURPOSE: To look for possible changes in iris blood vessels that might precede the formation of true exfoliation material, and to correlate these changes, if present, to aging of the iris. METHODS: Iris blood vessels of 10 clinically normal irises from 10 eyes (ages: 1 day-80 years), 4 irises with exfoliation (ages: 64-80 years) and 3 irises from primary open-angle glaucoma (POAG) (ages: 27-65 years) were examined with an electron microscope. RESULTS: Pronounced multilayering of the basal lamina around the vessels, abnormal excessive formation of microfibrils, presence of atrophic invaginations in the outer cell membranes of endothelial cells containing interlacing basal lamina, and an apparent decrease in the perivascular collagen fibers were evident in exfoliative iris vessels devoid of true exfoliation material. Similar, but much milder, changes were evident in normal aged and POAG irises. CONCLUSIONS: Abnormal elastic tissue and/or basal lamina production plays a role early in the formation of exfoliation material around iris blood vessels.

Adult↗
PubMed1998

Mechanism of intraocular pressure elevation during hemodialysis.

PURPOSE: To detect the mechanism of intraocular pressure elevation during hemodialysis. METHODS: We measured intraocular pressure, as well as serum osmolality and plasma CO2 pressure, every 30 min during hemodialysis, in 5 eyes with severely compromised aqueous outflow facility (Group A) from 4 renal failure patients. The same measurements were repeated on the same eyes using intravenous hyperosmotic Glyceol to prevent a rapid change in serum osmolality. We also measured the same parameters on 8 eyes with normal aqueous outflow facility (Group B) from 5 patients. The mean +/- SE of percent changes in each parameter was used for the statistical analysis. RESULTS: In Group A, the mean percent change of intraocular pressure increased significantly after 90 min, with the exception of the change at 180 min. The mean percent change of serum osmolality decreased significantly after starting dialysis. A negative correlation in the mean percent change of intraocular pressure with serum osmolality was detected (r = -0.759, r < 0.0001). The administration of intravenous hyperosmotic agent prevented significant changes in not only serum osmolality but also intraocular pressure. In Group B, the mean percent change in intraocular pressure showed no significant difference at any time, although the change in serum osmolality decreased significantly. CONCLUSION: A remarkable rise in intraocular pressure occurs during hemodialysis in eyes with an impaired aqueous outflow, when serum osmolality decreases rapidly.

Aged↗