Biomedical subjects

T Miki

Publications and source records attributed to T Miki.

At least 1,099 records · Page 61Linked to original sources

PubMedDate not supplied

Transcriptional activation by the Werner syndrome gene product in yeast.

Werner syndrome (WS) is characterized by the premature occurrence of many age-related features. Before the cloning of the gene for WS (WRN), several reports suggested that transcriptional defects of genes may relate to the mechanisms of the occurrence of WS and natural aging. Because WRN, which encodes a helicase (WRN-H), has been cloned, we are attempting to clarify the mechanism of the transcriptional abnormalities found in WS cells, using WRN and WRN-H. In this article, we studied transcriptional activation of a promoter by WRN-H in a yeast assay system as a first step. The results showed that WRN-H functions as a transcriptional activator in the system. Furthermore, we performed additional transcriptional assays using various parts of WRN to define the critical region of WRN-H for transcriptional activation in yeast. The results revealed the critical region for the activation most likely mapped to the region of 315 to 403 aa. The region of 404 to 1309 aa may also effect activation in the presence of the critical region. The two regions contain an acidic domain, and the region of 404 to 1309 aa also contains a helicase domain. If this transcriptional activation by WRN-H occurs also in human cells in vivo, direct activation of the promoters by WRN-H could explain the results of somatic cell hybrid studies as well as the overexpressed genes detected in WS cells. However, our results should be interpreted with caution, because thus far, the transcriptional activation by WRN-H were only demonstrated using one promoter in a yeast system.

DNA Helicases↗

PubMedDate not supplied

Long-term follow-up of severe central serous chorioretinopathy using indocyanine green angiography.

BACKGROUND: The severe types of central serous chorioretinopathy (CSC) have a chronic nature, suggesting that a pathological process persists subclinically. Indocyanine green (ICG) angiography recently revealed intrachoroidal dye leakage and its static nature in CSC. As the intrachoroidal dye leakage was suspected to be relevant to the disease process, the long-term persistence of intrachoroidal ICG leakage was examined in four patients of the severe types of CSC. METHODS: ICG angiography was performed periodically over more than three years in three patients and two years in one patient. One patient had CSC with bullous retinal detachment, and the other three had chronic CSC or diffuse retinal pigment epitheliopathy. RESULTS: Intrachoroidal ICG leakage persisted in all the patients. However, a change in location of persistent intrachoroidal leakage or disappearance of intrachoroidal leakage regardless of no progression of retinal pigment epithelial alteration was noted in one eye of two patients. CONCLUSIONS: Pathology causing intrachoroidal ICG leakage persisted subclinically for a long period. However, location and extent of the intrachoroidal leakage could change during a long-term follow-up period.

Adult↗

PubMedDate not supplied

Efficacy of sildenafil as the first-step therapeutic tool for Japanese patients with erectile dysfunction.

The aim of this study was to assess the efficacy of sildenafil as the first-step tool for erectile dysfunction (ED) in Japanese males. Between March 1999 and March 2003, 281 patients were prescribed five tablets of sildenafil (50 mg) as the first step in the therapeutic management of ED. Of the 281 patients, 206 were evaluable patients. The overall success rate in achieving sexual intercourse in subjects after taking sildenafil was 77.2% (159/206), while 22.8% (47/206) were unsuccessful. The success rates in men with functional ED and organic ED were 91.4% (85/93) and 65.5% (74/113), respectively (P<0.0001). Overall, transient adverse effects of sildenafil occurred in 16 (8%) males. Intolerable adverse effects (edema and dizziness) occurred in only 1% of patients (2/206). Sildenafil citrate may be recommended as the first choice drug for ED because of its high success rate and low invasiveness.

Adult↗

PubMedDate not supplied

Efficacy of sildenafil for Japanese patients with audio-visual sexual stimulation (AVSS) test by the RigiScan Plus.

Sildenafil is most effective in men with mild-to-moderate ED, but not severe ED in Japan. In order to evaluate the efficacy of sildenafil, we conducted the present study using the AVSS test by the RigiScan Plus. The subjects were 56 patients (age: 34-82 years, mean: 60.5 years) with ED. The IIEF5 questionnaire and the AVSS test were conducted before and after administration of sildenafil. The penile rigidity could not be measured in 19 patients. Of these 19, sildenafil was effective in 7 and not effective in 12. The 7 cases in whom sildenafil was effective were all false-negatives. The sensitivity of sildenafil was 84%, and its specificity was 100%. This study suggests that the AVSS test by RigiScan Plus can objectively evaluate the efficacy of sildenafil, and shows potential for predicting that efficacy.

Adult↗

PubMedDate not supplied

Construction of a plasmid vector for the regulatable high level expression of eukaryotic genes in Escherichia coli: an application to overproduction of chicken lysozyme.

A novel expression vector pKP1500 for synthesizing unfused protein in Escherichia coli was constructed. pKP1500 perserves the tac promoter, the lacZ SD sequence, unique restriction sites (EcoRI, SmaI, BamHI, SalI, PstI and HindIII) and the rrnB terminators of pKK223-3, but the replication origin is replaced with that of pUC9. Construction of this plasmid is based upon the observation that the copy number control of pUC9 is temperature dependent. At 28 degrees C, the copy number of pKP1500 is less than 25 per chromosome, approximately the same copy number as that of pKK223-3, which contains the replication origin of pBR322, whereas at 42 degrees C, the copy number increases about 10 times and reaches up to 230 copies per chromosome. The main advantage of this system is that the temperature-dependent copy control and regulatable expression of the tac promoter make cells carrying pKP1500 derivatives stable against selective pressure by detrimental overproduction of foreign proteins at a low temperature and permits high expression of cloned DNAs at a high temperature. When chicken lysozyme cDNA carrying the initiation codon (ATG) immediately upstream from the Lys1 codon was inserted downstream from the tac promoter and the SD sequence, the pKP1500 derivative produced lysozyme at about 25% of the total cellular proteins. This value is more than 10 times higher than that obtained with the pKK223-3 derivative carrying the same lysozyme cDNA. By comparison, the expression of eukaryotic genes from the tac promoter reported by others has usually been less than a few % of the total cellular protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Point mutation of alanine (31) to valine prohibits the folding of reduced lysozyme by sulfhydryl-disulfide interchange.

In the preceding paper in this issue, we described the overproduction of one mutant chicken lysozyme in Escherichia coli. Since this lysozyme contained two amino acid substitutions (Ala31----Val and Asn106----Ser) in addition to an extra methionine residue at the NH2-terminus, the substituted amino acid residues were converted back to the original ones by means of oligonucleotide-directed site-specific mutagenesis and in vitro recombination. Thus, four kinds of chicken lysozyme [Met-1Val31Ser106-, Met-1Ser106-, Met-1Val31- and Met-1 (wild type)] were expressed in E. coli. From the results of folding experiments of the reduced lysozymes by sulfhydryl-disulfide interchange at pH 8.0 and 38 degrees C, followed by the specific activity measurements of the folded enzymes, the following conclusions can be drawn: (i) an extra methionine residue at the NH2-terminus reduces the folding rate but does not affect the lysozyme activity of the folded enzyme; (ii) the substitution of Asn106 by Ser decreases the activity to 58% of that of intact native lysozyme without changing the folding rate; and (iii) the substitution of Ala31 Val prohibits the correct folding of lysozyme. Since the wild type enzyme (Met-1-lysozyme) was activated in vitro without loss of specific activity, the systems described in this study (mutagenesis, overproduction, purification and folding of inactive mutant lysozymes) may be useful in the study of folding pathways, expression of biological activity and stability of lysozyme.

Alanine↗

PubMedDate not supplied

Enhancement of interleukin-2-induced lymphokine-activated killer activity by interleukin 7 against autologous human renal cell carcinoma.

Adjuvant immunotherapy with interferons and/or interleukin 2 (IL-2) is widely used for advanced kidney cancer. However, the results are not satisfactory so far. The purpose of this study is to evaluate the inducible activity of lymphokine-activated killer (LAK) cells against autologous human renal cell carcinoma. The effect of interleukin 7 (IL-7) on IL-2-induced LAK activity was assessed by the autologous assay system which we have established. Peripheral blood lymphocytes from patients with renal cell carcinoma were stimulated with IL-2 and/or IL-7, and tested for antitumor activity against autologous renal cell carcinoma. In all 10 cases tested, IL-7 alone induced LAK activity. Moreover, IL-2-induced LAK activity was augmented by the concomitant addition of IL-7. Flow cytometry revealed an increase in IL-2-receptor-positive lymphocytes following incubation with IL-7. These results suggest that combination therapy using IL-2 and IL-7 may be a useful treatment for patients with advanced renal cell carcinoma.

Aged↗

PubMedDate not supplied

Genetic association between Alzheimer disease and the alpha-synuclein gene.

alpha-Synuclein has been isolated as a component of amyloid in addition to the major A beta peptide in Alzheimer disease (AD). However, there are conflicting reports regarding the association of alpha-synuclein gene polymorphism with AD. Using a novel and common polymorphism in intron 3, we examined the relationship between AD and alpha-synuclein and apolipoprotein E (ApoE) genes in 183 Japanese AD patients and 210 controls. Carriers of the alpha-synuclein deletion (D) allele had a 2.2-fold increased risk of developing AD than noncarriers in women. The odds ratio for the ApoE epsilon 4 and the alpha-synuclein D allele was 11.4 in women. The results showed that the alpha-synuclein gene is associated with sporadic AD in women, independent of ApoE epsilon 4 status.

Aged↗

PubMedDate not supplied

Digital fluorescein fundus angiography with DFC-512 and IMAGEnet systems.

Image processing with direct acquisition digital fundus fluorescein angiography using the OIS DFC-512 and Topcon IMAGEnet were assessed. Fundus diseases included central and branch retinal vein occlusion, diabetic retinopathy, age-related macular degeneration, central serous choroidopathy and angioid streaks. Analogue images were taken with Kodak Tri-X 35 mm film as well. Although the resolution of the original image was less than that of 35 mm film, it was improved by image processing, particularly contrast enhancement. One type of contrast enhancement, available in both systems, exaggerated lack of light at the peripheral area of the original image. This drawback was not seen with another type of enhancement processing, available in IMAGEnet. However, the latter produced an artificial hypofluorescent area around an intensely hyperfluorescent lesion and also exaggerated hyper- and hypo-fluorescent patches of the background. Nevertheless, these processing methods were particularly useful in case of media opacity like cataract, even when the 35 mm film picture is not clear. Other processing techniques like pseudocolor and relief, etc. were used just for different ways of presentation. The two systems are basically equivalent, except for contrast enhancement. There was no problem for diagnosis in both systems, but the artificial effects must be borne in mind when interpreting the image.

Choroid Diseases↗

PubMedDate not supplied

Intrachoroidal dye leakage in indocyanine green fundus angiography after experimental commotio retinae.

Dye leakage in sodium fluorescein (FLUO) fundus angiography indicates damage to the blood-retinal barrier. However, dye leakage in indocyanine green (ICG) fundus angiography does not mean the same, because of the larger molecular size of the dye and impermeability of the choroidal vessels to it. The possibility of dye leakage in ICG angiography has not yet been revealed in an experimental study in which the blood-retinal barrier is undamaged. We report here that intrachoroidal dye leakage may occur in ICG angiography in an experimental model of the traumatic retinal opacity of the rabbit eye, even when the blood-retinal barrier is undamaged. This mechanism of dye leakage in ICG angiography is quite different from the leakage of FLUO angiography. Pathological choroidal vessels with increased permeability, such as choroidal neovascularization under the retinal pigment epithelium, can be observed using ICG angiography.

Animals↗

PubMedDate not supplied

Change of retinal correspondence in monocularly reduced intensity of stimulus.

We analyzed the retinal correspondence with a phase difference haploscope on reducing the stimulus intensity of a monocular image with a series of neutral density filters. Ninety-one exotropes were examined by this method. Five cases changed from normal to anomalous correspondence when the stimulation of the strabismic eye was reduced. Two cases showed anomalous correspondence without a filter, but normal correspondence with a reduced stimulus of the normal eye. All these seven cases showed normal correspondence with any other test. The results suggest that masked anomalous correspondence becomes manifest in some cases when the strabismic eye is stimulated more intensely than the normal eye. These cases display both normal and anomalous correspondence and this condition may be called dual correspondence.

Adolescent↗

PubMedDate not supplied

Computer assisted image analysis using the subtraction method in indocyanine green angiography.

The choroidal vessels are three dimensionally distributed and very complex in their patterns. They often appear to be overlaid in indocyanine green (ICG) angiograms so it is harder to analyze ICG angiography than fluorescein angiography. When an earlier frame is subtracted from a later frame in a sequence of angiograms, the fluorescence which has increased during the time between the two frames can theoretically be demonstrated. We applied computer-assisted image subtraction methods in selected clinical cases of directly acquired digital ICG angiography to demonstrate how this method works. We used software already installed in an IMAGEnet computer system (Topcon) for image subtraction. We applied the subtraction technique in 18 cases with various diseases. When two images with a time difference of several seconds were subtracted, filling of the choriocapillaris, the neovascularization or the pathological vessels could be observed. When the images had a time difference of several minutes, intrachoroidal dye leakage could be seen more clearly. This method is very helpful for analyzing pathological changes in ICG angiography in clinical cases, when two images are selected appropriately.

Adult↗

PubMedDate not supplied

Clinical effect of etidronate on alveolar pyorrhoea associated with chronic marginal periodontitis: report of four cases.

Etidronate 200 mg daily was administered to four female patients with periodontitis and resultant alveolar pyorrhoea for periods of 2 weeks, followed by off-periods of 10 weeks or more, for 2-3 years. The macroscopic appearance of gingival mobility of the teeth, depth of periodontal pockets, and X-ray findings of alveolar bones improved markedly during this time. The effects were first observed after 6-12 months of treatment. These findings indicate that bisphosphonates may be effective in the treatment of periodontitis and resultant alveolar pyorrhoea. The effect may be mediated by the inhibitory action on bone resorption and the anti-inflammatory action of etidronate. Concomitant conventional dental management is also required.

Bone Resorption↗

PubMedDate not supplied

Suppression of alveolar bone resorption by etidronate treatment for periodontal disease: 4- to 5-year follow-up of four patients.

Four women with periodontitis received intermittent cyclical etidronate (etidronate administered orally at a dose of 200 mg/day for 2 weeks, at intervals of 10-12 weeks or 6 months) for 4-5 years in addition to ordinary dental therapy. Alveolar bone density was measured using a new method comparing the percentage increase in density. Mean alveolar bone density increased significantly during intermittent cyclical etidronate treatment. Significant reductions were observed in the mobility of the teeth and the depth of periodontal pockets. There were significant correlations between alveolar bone density and both mobility of the teeth and the depth of the alveolar pockets. It is concluded that increases in alveolar bone density are associated with the clinical benefits of etidronate in the treatment of periodontitis.

Absorptiometry, Photon↗

PubMedDate not supplied

Immunohistological localization of autoantigens detected by serum autoantibodies from mice with experimental autoimmune orchitis without using adjuvants.

Recently, a murine model of testicular autoimmunity was produced in mice by subcutaneous injections with viable syngeneic testicular germ cells alone, without depending on the use of any adjuvants or immunopotentiators. In this article, histological localization of autoantigens detected by circulating autoantibodies was immunohistochemically studied by reacting the immune sera with frozen sections of testes from mice of various ages. The study showed that the reactivity of immune sera was detected in the testis sections of normal mice older than 24 days of age but not in those of mice younger than 20 days of age. The immunostain was detected at proacrosomal, acrosomal, and other cytoplasmic regions of variously shaped developing spermatids but never on pachytene spermatocytes, basal compartment germ cells, or the supporting tissue of the seminiferous tubules.

Adjuvants, Immunologic↗

PubMedDate not supplied

Cancer risk in space due to radiation assessed by determining cell lethality and mutation frequencies of prokaryotes and a plasmid during the Second International Microgravity Laboratory (IML-2) Space Shuttle experiment.

We participated in a space experiment conducted during the 2nd International Microgravity Laboratory Mission (IML-2) project. The aim of our study was to investigate the effects of space radiation, i.e., high-LET (linear energy transfer) cosmic radiation, on living organisms in the 'Realtime Radiation Monitoring Device (RRMD)'. The biological samples, dried E. coli DNA repair-deficient mutant cells and shuttle vector plasmid pZl89 DNA, were prepared and placed in a biospecimen box sandwiched between 'Harzlas' plastic radiation detectors. This box was then loaded into the RRMD sensor unit in the Space Shuttle 'Columbia' and an identical box was left in the NASA John F. Kennedy Space Center (KSC) as a control. 'Columbia' (flight No. STS-65) was launched from KSC in Florida, USA on July 8, 1994. The mission duration was 14.75 days and after 'Columbia' returned to earth, we studied (i) the lethal and mutagenic effects of high-LET cosmic radiation on E. coli mutants and (ii) the relationship between high-LET cosmic radiation and the mutation frequency of pZ189 DNA. There were virtually no differences between the cell viabilities of the space and control samples of Escherichia coli KMBL3835 (wild-type), KY383 (lexA-), KY385 (recA-) and KY386 (uvrA-), nor between the mutation frequency ratios of the space and control E. coli mutant samples. Furthermore, the survival and mutation frequency of the supF gene of pZ189 DNA space samples did not differ from those of the control samples. We concluded there was no cancer risk during this Space Shuttle flight.

Cosmic Radiation↗

PubMedDate not supplied

Radiotherapy for adrenal gland metastasis from lung cancer: report of three cases.

Adrenal gland metastasis is often observed during the clinical course of patients with lung cancer. However, treatment of adrenal gland metastasis is seldom considered because of the systemic spread of the disease. Treatment with curative intent is very rare, but palliative treatment may sometimes be considered when symptoms such as flank pain are observed. Three cases of adrenal gland metastasis were reported. Two of them received surgery for lung cancer and developed a sole metastasis of the adrenal gland. Case 1 developed a sole left adrenal gland metastasis with left flank pain 14 months after surgery for large cell carcinoma of the lung. Curative radiotherapy after intra-arterial chemotherapy was given. A good response was obtained, and he has been alive for 2 years and 9 months. Case 2 developed a right adrenal gland metastasis after radiotherapy for brain metastasis, after having received right upper lobectomy because of SCLC. The increase in the size of the right adrenal gland led us to treat the lesion before symptoms developed. Radiotherapy was given on an outpatient basis. Case 3, who was previously treated with chemoradiotherapy for SCLC, developed brain, liver, and bilateral adrenal gland metastasis. Huge adrenal gland metastases displaced the pancreas and caused severe pain with the increase in serum amylase level. Concurrent radiotherapy with systemic chemotherapy was given and remarkable shrinkage of the adrenal gland metastases was obtained together with pain relief. Cases 2 and 3 died after 8 and 4 months, respectively. In some cases, radiotherapy for adrenal gland metastasis is a good palliative therapy even in the advanced stage patients. Radiotherapy can sometimes curatively treat adrenal metastasis from NSCLC, as in our Case 1, in which adrenalectomy appeared difficult at the time of recurrence.

Adrenal Gland Neoplasms↗

PubMedDate not supplied

Incising the thick retrolental fibrovascular tissue with a hooked sclerotome in persistent hyperplastic primary vitreous.

A technique for incising thick retrolental fibrovascular tissue and extensive cyclitic membrane is reported in a case of anterior persistent hyperplastic primary vitreous. A membranectomy was performed in a 1-month-old post-lensectomy baby via a limbal approach. A sclerotome tip was hooked to cut through an extremely thick fibrovascular tissue by rotating the sclerotome by its grip. Sutherland microscissors (Grieshaber, Switzerland) and a vitrectomy cutter were used for further membranectomy. The baby was followed-up until age 18 months. A total of 3 membranectomy sessions were required because of rapid cyclitic membrane formation, severe centripetal retraction of the membrane on the ciliary processes, and posterior synechia. Thorough membranectomy and cutting the iris edge maintained a clear pupillary area during the 13-month postoperative period. Extremely thick retrolental fibrovascular tissue is a challenging condition that can be dealt with by delicate instrumentation.

Anterior Eye Segment↗