Biomedical subjects

T Yasuhara

Publications and source records attributed to T Yasuhara.

At least 37 records · Page 2Linked to original sources

PubMed2000

Pars plana vitrectomy for regression of choroidal neovascularization with age-related macular degeneration.

OBJECTIVE: In age-related macular degeneration, the posterior vitreous surface often remains attached to a higher degree than expected for the patient's age, suggesting the involvement of the posterior vitreous membrane in the pathophysiology of choroidal neovascularization. Thus, we performed simple pars plana vitrectomy and artificial posterior vitreous detachment in order to induce regression of choroidal neovascularization. METHODS: Vitrectomy was performed in 12 eyes of 11 patients with age-related macular degeneration in whom the posterior vitreous surface remained attached, and in whom there was evidence of highly active choroidal neovascularization. The posterior vitreous membrane was artificially detached during surgery, but photocoagulation and/or a subretinal procedure for choroidal neovascularization was not performed. Patients underwent fluorescein and indocyanine green angiography both pre- and postoperatively to assess the status of choroidal neovascularization. RESULTS: Six months after surgery, 6 of the 12 eyes showed regression of choroidal neovascularization, and in 2 eyes it had disappeared completely. Subretinal exudative changes in 8 eyes had improved. Visual acuity testing showed improved vision in 4 eyes, unchanged vision in 4 eyes, and worsening of vision in 4 eyes. The final best corrected visual acuity was 10/20 or better in one eye, 10/ 20 to 20/200 in 7 eyes, and 20/200 or worse in 4 eyes. CONCLUSION: The results of the present study suggest the involvement of the posterior vitreous membrane in the pathophysiology of age-related macular degeneration. Furthermore, the minimally invasive pars plana vitrectomy may represent a new treatment for age-related macular degeneration.

Aged↗

PubMed2000

Production of enzymatically and immunologically active Der f 1 in Escherichia coli.

Der f 1 is a major house dust mite allergen belonging to the cysteine protease family. Because of the great demand for clinical and research use of this allergen, much effort to establish an efficient method of preparing purified Der f 1 has been made. We constructed an isopropyl-beta-D-thiogalactopyranoside-inducible expression plasmid to produce the pro-form of Der f 1 in Escherichia coli. The recombinant product was accumulated as insoluble inclusion bodies in cells. The solubilized inclusion bodies were found to be successfully renatured by two-step gel filtration chromatography. About 70 mg of pro Der f 1 were properly refolded by this method from 1 liter of culture. Acid treatment of the renatured pro Der f 1 resulted in the autocatalytic removal of the pro-sequence. The obtained mature form of Der f 1 bound IgE in patient sera and induced the release of histamine from peripheral blood leukocytes equally to native Der f 1. Furthermore, mature Der f 1 obtained by this method had identical protease activity with native Der f 1. We also discussed the contribution of the pro-sequence and the sugar chain of Der f 1 to its antigenic and enzymatic activity. This is the first report to produce an active mature form of recombinant Der f 1 in E. coli.

Allergens↗

PubMed2000

[Transvenous embolization for cavernous dural arteriovenous shunts: about the intracranial venous approach to the cavernous sinus].

Recently, the first choice of therapy for cavernous dural arteriovenous shunts (CdAVS) is transvenous embolization. Usually the approach routes for cavernous sinus are the inferior petrosal sinus (IPS), the superior ophthalmic vein (SOV) in most cases and the superior petrosal sinus (SPS) in rare case. But, it is difficult for us to treat patients in whom there are no extracranial veins through which to approach the cavernous sinus, with transvenous embolization. We presented the case in which intracranial transvenous approach to the cavernous sinus and transvenous embolization were performed and in which we achieve good results. In this article, we presented a case with Barrow's type D CdAVS and cortical venous drainage. At first, transarterial embolization was performed to decrease the amount of venous drainage for the purpose of eliminate convulsions and consciousness disturbance. However, cortical venous drainage continued. Moreover bilateral dilated SOVs normalized and bilateral IPSs were not visible, so we decided that it was impossible to carry out the transvenous embolization via extracranial veins. Transvenous embolization to the left cavernous sinus via the intracranial ophthalmic vein between the superior ophthalmic fissure and the inferior ophthalmic fissure after craniotomy was performed. Then, the transvenous embolization to the right cavernous sinus was carried out through the right superficial middle cerebral vein after craniotomy. The results were good and chemosis and bilateral abducens palsy diminished immediately. Trans-intracranial venous embolization for CdVAS is a very useful therapy when no extracranial veins exist for transvenous embolization.

Aged↗

PubMed2000

[Investigation of corneal autofluorescence in diabetic patients].

PURPOSE: The investigation of corneal autofluorescence in diabetic patients. OBJECTS AND METHODS: Corneal autofluorescence was investigated with a newly-developed fluorophotometer (wave length: excitation, 290-390 nm; emission, 430-630 nm) having, fluorescence characteristics involving those of reduced pyridine nucleotides (PN) and advanced glycation endoproduct (AGE) except pentosidine and pyrraline. Twenty-eight patients with non-insulin-dependent diabetes mellitus and sixty-seven healthy volunteers were studied. RESULTS: The corneal autofluorescence was 1.65 times higher than that of controls (p < 0.0001). In non-insulin-dependent diabetes mellitus, the corneal autofluorescence was not correlated significantly with various diabetic parameters in blood (r < 0.4). In controls, the corneal autofluorescence was correlated significantly with age (r = 0.438). CONCLUSION: The corneal autofluorescence has some relation with PN and AGE accumulation in the cornea.

Adolescent↗

PubMed1999

Allelic imbalance in chromosome band 18q21 and SMAD4 mutations in ovarian cancers.

Recently, three candidate tumor suppressor genes, SMAD2 (MADR2/JV18-1), SMAD4 (DPC4), and DCC, were identified in chromosome band 18q21. We examined allelic imbalance (AI) in 18q21 using six polymorphic microsatellite markers in 38 primary ovarian cancers and four ovarian borderline tumors. AI at one or more loci was detected in 15 of 37 (41%) informative ovarian cancers and in none of the four borderline tumors. Frequent AI was detected at the D18S46 (31%) and D18S474 (36%) loci, which were adjacent to the SMAD4 gene, and at the D18S69 (33%) locus, which was telomeric to the DCC gene. Therefore, we searched for mutations of the SMAD4 gene in 42 primary tumors and eight cell lines by PCR-SSCP and sequencing analyses. Missense mutations were detected in two ovarian tumors and three ovarian cancer cell lines, whereas silent mutation was detected in a primary ovarian cancer. These results suggest that there are at least two tumor suppressor genes on chromosome arm 18q and that SMAD4 is of importance in ovarian tumorigenesis.

Alleles↗

PubMed1999

Multiple cranial arteriovenous malformations in a child with eventual blindness in the affected eye.

PURPOSE: To report a case of multiple cranial arteriovenous malformations involving the orbit and retina. METHOD: Case report. We treated a 7-year-old girl who was diagnosed with a left submaxillary, a left retinal, a left orbital, and a middle subdural arteriovenous malformation. RESULTS: Enlargement of the arteriovenous malformations, except for the retinal arteriovenous malformation, was observed. After external carotid artery embolizations and radiation therapy for uncontrolled oral cavity bleeding, loss of light perception in the affected eye occurred, but no marked changes occurred in the retinal arteriovenous malformation. CONCLUSION: This rare case suggests that the clinical finding of a stable retinal arteriovenous malformation may be associated with enlargement of arteriovenous malformation lesions at other sites.

Blindness↗

PubMed1999

Vitrectomy for rhegmatogenous or tractional retinal detachment with familial exudative vitreoretinopathy.

OBJECTIVE: To examine the anatomic features and surgical indications of familial exudative vitreoretinopathy (FEVR) complicated with rhegmatogenous or tractional retinal detachment. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Twenty-eight eyes of 25 patients who had either clinically suspected or fully diagnosed FEVR. Of these, 25 had rhegmatogenous retinal detachment, 2 had tractional retinal detachment, and 1 had tractional retinal detachment plus vitreous hemorrhage. INTERVENTIONS: The authors carefully observed the vitreoretinal interface during surgery, studied the clinical and anatomic features of FEVR, and then evaluated the surgical results. RESULTS: The vitreoretinal adhesions were so strong in the peripheral avascular area that iatrogenic retinal breaks easily occurred in 22 of 28 eyes. In all cases, the bimanual technique with vitreous scissors and forceps was required to dissect the posterior vitreous membrane from the retinal surface. The retina was reattached in 24 of 28 cases (85.7%), and visual acuity improved in 20 eyes (71.4%). CONCLUSION: Dissection of the vitreous in the peripheral avascular area is very difficult in FEVR, and those patients for whom this procedure was not successfully performed may have a poorer prognosis.

Adolescent↗

PubMed1999

The allergens of Dendropanax trifidus Makino and Fatsia japonica Decne. et Planch. and evaluation of cross-reactions with other plants of the Araliaceae family.

cis-9,17-Octadecadiene-12,14-diyne-1,16-diol (I), an analog of falcarinol has been identified in our previous report as an active component of Dendropanax trifidus and a strong sensitizer. In this report, 16-hydroxy-cis-9,17-octadecadiene-12,14-diynoic acid (II) and cis-9,trans-16-octadecadiene-12,14-diynoic acid (III) were elucidated as 2 other active components of the plant. Compound I, however, presented with the highest concentration and showed a stronger reaction on patch testing. The leaves of Fatsia japonica Decne. et Planch. were also found to contain compound I, but the amount was found to be 7x more in Dendropanax trifidus than in Fatsia japonica. 5 subjects with hypersensitivity to Dendropanax trifidus and compound I showed positive reactions when patch tested with the leaves of Hedera helix L. and Schefflera arboricola. 1 of these also showed a positive reaction to the extract of Panax ginseng root powder diluted 1% in ethanol. There was cross-reaction among these plants, which all belong to the Araliaceae family.

Adult↗

PubMed1999

A case of bacterial endophthalmitis following perforating injury caused by a cat claw.

A case of bacterial endophthalmitis following a perforating ocular injury caused by a cat claw is reported. The scleral wound was sutured immediately following the injury and systemic antibiotics were administered. Despite this treatment, endophthalmitis occurred 3 days after the injury. The endophthalmitis was resolved by pars plana vitrectomy, however preretinal reproliferation and retinal detachment subsequently occurred. After reoperation the retina was reattached and the corrected visual acuity improved from 10 cm/HM to 20/200. Pseudomonas aeruginosa was detected in cultured vitreous humor that was collected during surgery. This case illustrates the possibility of endophthalmitis being caused by gram negative bacillus in cases of perforating injuries caused by animal claws. Perforating ocular injuries caused by animal claws are relatively rare. Here we report a case of endophthalmitis due to Pseudomonas aeruginosa that occurred after a perforating injury caused by a cat claw. The eye was treated by pars plana vitrectomy.

Adult↗

PubMed1998

Isolation and structure of pompilidotoxins, novel peptide neurotoxins in solitary wasp venoms.

Novel peptide neurotoxins, alpha- and beta-pompilidotoxins (alpha- and beta-PMTXs), were purified from the venoms of the solitary wasps Anoplius samariensis and Batozonellus maculifrons. Their structures were analyzed mostly by MALDI-TOF-MS, which were corroborated by solid-phase synthesis. alpha-PMTX, with 13 amino acid residues and the sequence of Arg-Ile-Lys-Ile-Gly-Leu-Phe-Gln-Asp-Leu-Ser-Lys-Leu-NH2, greatly potentiates synaptic transmission of lobster leg muscle by the presynaptic mechanisms. beta-PMTX, in which the lysine residue at 12 position of alpha-PMTX was replaced with arginine, was more potent than alpha-PMTX.

Animals↗

PubMed1998

Quantitative determination of biological sulfhydryl groups by postcolumn derivatization and elucidation of microheterogeneity of serum albumins.

A quantitative analytical system for biological sulfhydryl compounds has been developed using an ion-pair reagent with isocratic elution and an on-line postcolumn derivatization with Ellman-type reagents. As human or bovine serum albumin has 35 cysteinyl residues, one cysteinyl residue exists as a free sulfhydryl moiety, and this gives rise to the microheterogeneity in serum albumin. Here we report for the first time the quantitative characterization of the microheterogeneity of serum albumin. Cysteine was found to be the major molecule attached to the sulfydryl group of the serum albumins. Although glutathione could not be detected, the Cys-Gly element of glutathione was found. Freshly prepared human serum albumin from healthy volunteers contained 0.46 nmol of Cys/mL of serum, 0.24 nmol of Cys-Gly/mL of serum, and very small amounts of glutathione (0.02 nmol/mL).

Adult↗

PubMed1998

Vitrectomy for proliferative diabetic retinopathy with asteroid hyalosis.

PURPOSE: To characterize the clinical features of proliferative diabetic retinopathy (PDR) with asteroid hyalosis treated by pars plana vitrectomy. METHODS: Vitrectomy was performed in 26 eyes with PDR accompanied by asteroid hyalosis (7 eyes with vitreous hemorrhage, 6 eyes with tractional retinal detachment with vitreous hemorrhage, and 13 eyes with tractional retinal detachment without vitreous hemorrhage). We observed the occurrence of posterior vitreous detachment intraoperatively and evaluated the clinical characteristics retrospectively. RESULTS: In 24 eyes, posterior vitreous detachment was slight, necessitating artificial detachment. Of the 26 eyes, 20 experienced iatrogenic retinal breaks and 6 (23%) experienced postoperative retinal detachment due to iatrogenic breaks. Three cases worsened to anterior proliferative vitreoretinopathy and retinal reattachment could not be achieved. CONCLUSIONS: In vitrectomy for PDR with asteroid hyalosis, and in cases of simple vitreous hemorrhage, surgery should be performed with full understanding of the anatomic characteristics. Notably, if posterior vitreous detachment is not present, the occurrence of iatrogenic retinal breaks is more likely.

Adult↗

PubMed1998

Tissue specific-distribution and metabolism of vitamin A are affected by dietary protein levels in rats.

The effect of dietary protein levels on tissue-specific distribution and metabolism of vitamin A was studied in rats given [15-14C] retinol (14C-ROH). The weanling rats were fed a low level vitamin A diet for 10 days, then rats (15 rats per group) were divided into 2 groups; one was given a 40% casein diet as a high protein diet (HP-diet), and the other a 5% casein diet as a low protein diet (LP-diet). After 10 days feeding on these diets, 14C-ROH (5 microCi/rat) was given to both groups, HP-diet and LP-diet, by intraperitoneal injection. The radioactivity in the exhalated gases, urine and feces was measured to estimate the rate of vitamin A metabolism. The tissue specific-distribution of ROH was studied in terms of the radioactivities of the ROH fractions separated by HPLC. The hepatic 14C-ROH content in the HP-diet group was lower than that in the LP-diet group at 24, 48, and 72 hours after administration of 14C-ROH. In contrast, 14C-ROH content in serum, spleen, pancreas, and small intestinal mucosa in the HP-diet group was higher than that in the LP-diet group. The radioactivity of the exhalated gas and feces was higher in the HP-diet group. These results suggest that metabolism of vitamin A is higher with intake of a HP-diet. Thus, dietary protein levels may affect tissue-specific distribution and metabolism of vitamin A, thereby modulating the actions of this vitamin.

Animals↗

PubMed1997

Alpha-pompilidotoxin (alpha-PMTX), a novel neurotoxin from the venom of a solitary wasp, facilitates transmission in the crustacean neuromuscular synapse.

A new neurotoxin, named alpha-pompilidotoxin (alpha-PMTX) has been found in the venom of the solitary wasp Anoplius safnariensis. In the neuromuscular synapse of the lobster walking leg preparation, alpha-PMTX (10-100 micro/M) caused great enhancement of both the excitatory and inhibitory postsynaptic potentials. Recordings of the excitatory post synaptic currents (EPSCs) at the synaptic sites showed that alpha-PMTX reversibly and dose-dependently potentiates EPSCs. Alpha-PMTX may act primarily on the presynaptic membrane but the mode of action of the toxin is clearly different from other known facilitatory neurotoxins, such as alpha-latrotoxin, apamin or charybdotoxin. This novel toxin will serve as a useful tool in the research field of neuroscience.

Animals↗

PubMed1997

Detection of new spider toxins from a Nephilengys borbonica venom gland using on-line mu-column HPLC continuous flow (FRIT) FAB LC/MS and MS/MS.

Spider venom glands store various novel neurotoxic acylpolyamines which present potent and irreversible inhibition of the glutamatergic synapses. We have developed a new highly sensitive analytical method to detect and characterize structures of those neurotoxins stored in a single venom gland using micro bore column high performance liquid chromatography (HPLC)-continuous flow FRIT fast atom bombardment mass spectrometry (HPLC-FAB/MS) and tandem mass spectrometry (MS/MS) array detection system. The high-energy collision induced dissociation (CID) spectra of sodium cationized spider toxins produced very strong structurally informative product ions which afforded the location of nitrogen atoms and the connectivity of methylene units within the polyamines. This methodology permitted detection of 40 amino acid containing acylpolyamines in the venom of Nephilengys borbonica from which structures of only five compounds were previously known.

Animals↗

PubMed1997

The major allergen of Dendropanax trifidus Makino.

Dendropanax trifidus Makino (family Araliaceae, syn. Gilibertia trifida Makino) has been reported as causing allergic contact dermatitis in Japan. To identify the major allergen, fractionated extracts of fresh leaves of Dendropanax trifidus were patch tested on 2 patients with hypersensitivity to the plant. Cis-9,17-octadecadiene-12,14-diyne-1, 16-diol (I), an analog of falcarinol, was identified as an active component. 18 normal control subjects were patch tested with the leaf of Dendropanax trifidus and I diluted to 0.05% in pet. 4 of them showed active sensitization to the leaf of Dendropanax trifidus and I. Our results suggest that I is the major allergen of Dendropanax trifidus and is a strong sensitizer. The results of patch testing on patients and control subjects with the leaves of Fatsia japonica Decne. et Planch. and Hedera helix L., which also belong to the Araliaceae family, and urushiol are also shown.

Adult↗

PubMed1996

Corneal endothelial changes in schizophrenic patients with long-term administration of major tranquilizers.

PURPOSE: To examine corneal endothelial changes in schizophrenic patients who underwent long-term administration of major tranquilizers. METHODS: We performed slit-lamp examination and endothelial specular microscopy on 100 eyes of 50 schizophrenic patients (range, 31 to 68 years old; mean, 54 years) who underwent long-term (12 to 44 years) treatment with major tranquilizers. We also studied 50 eyes of 25 patients (range, 31 to 65 years old; mean, 53 years) with no history of corneal disease, as a control group of similar age. Mean cell density, coefficient of variation, and percentage of hexagonal cells were calculated and statistically compared between patients and controls using an unpaired t-test. RESULTS: Slit-lamp examination disclosed pigmentation of the cornea in nine eyes of five patients and pigmentation of the lens in 25 eyes (25%) of 35 patients. Corneal pigmentary changes were seen only in patients with lenticular changes. No eyes showed corneal edema. In contrast, no corneal abnormalities were seen in any control eye. Specular microscopic analysis showed mean cell density of 3,484.4 +/- 462.6 cells/mm2, coefficient of variation of 0.31 +/- 0.06 and percentage of hexagonal cells to be 60.2% +/- 7.5% in the patient group, and 3,291.3 +/- 384.4 cells/mm2, 0.32 +/- 0.07, and 60.6% +/- 7.0%, respectively, in the control subjects. There were no statistically significant differences between patient and control eyes in these three factors. The nine eyes with corneal pigmentation showed no significant differences in these three factors as compared with the control subjects. CONCLUSIONS: These results indicate that long-term treatment with major tranquilizers is not associated with morphometric abnormalities of the corneal endothelium.

Adult↗

PubMed1996

Direct expression of Der f2, a major house dust mite allergen, in Escherichia coli.

Der f2 protein in a highly antigenic form was directly expressed in bacteria. Plasmid pFLU11 derived from pKK233-2 was designed to express methionyl-Der f2 under the control of the trc promoter and it has the replication origin of pUC118 instead of its original to increase the copy number. This expression plasmid directed the synthesis of recombinant Der f2 (rDer f2) protein in an insoluble form of inclusion bodies in Escherichia coli cells. The high copy number plasmid pFLU11 conferred the efficient production of the Der f2 protein in E. coli, when compared to a nonchanged origin material. rDer f2 inclusion bodies were easily solubilized in urea and renatured by dialysis to assume the active form. The rDer f2 protein was purified by means of anion exchange and gel filtration chromatography. This expression system yielded about 10 mg of purified rDer f2 protein from the 1L culture. Purified rDer f2 protein reacted with IgE from patient sera almost identically to the native Der f2 in the RAST enzyme immunoassay and skin prick test.

Allergens↗