Biomedical subjects

K Kitahara

Publications and source records attributed to K Kitahara.

At least 37 records · Page 2Linked to original sources

PubMed1999

[Short-term fluctuation of blue-on-yellow perimetry in normal eyes].

PURPOSE: To evaluate short term fluctuation (SF) of blue-on-yellow perimetry (B/Y) as compared with white-on-white perimetry (W/W) in normal eyes. SUBJECTS AND METHOD: One eye each of 25 healthy persons underwent B/Y and W/W perimetry repeated 5 times each. The test subjects had no previous experience of perimetry. An automated perimeter, Humphrey Field Analyzer, model 750, was used throughout. RESULTS: The SF at the first session of B/Y perimetry averaged 2.02 dB. This value was significantly different from those of the subsequent 4 sessions. Each of SF of B/Y perimetry at the first two sessions was significantly different from that of W/W perimetry at the first two sessions. The SF of B/Y perimetry showed wider fluctuations than those of W/W perimetry at each session. CONCLUSION: B/Y perimetry in normal eyes showed individual differences as well as fluctuations between the initial and consecutive sessions. This feature has to be considered in interpretation of the findings.

Adolescent↗

PubMed1999

[Expression of brain-derived neurotrophic factor gene in retina following vitreous tap].

PURPOSE: Mechanical injuries to the retina following vitreous tap are reported to protect photoreceptor cells in a rat model of the retinal degeneration and enhance the survival rate of retinal ganglion cells in the optic nerve transection. Neurotrophic factors are presumably involved in the protective mechanisms. In order to see whether neurotrophic factors are synthesized in the retina, we studied the expression of neurotrophic factors in the retina following vitreous tap in rats. MATERIALS AND METHODS: One eye each of 20 mature rats received transscleral vitreous taps at three points of entry and retinal injury. The retinas were removed and examined at day 0 to 14 of treatment. RESULTS: Following injury, the retina showed increased expression of glial fibrillary acidic protein (GFAP) mRNA and brain-derived neurotrophic factor (BDNF) mRNA. There was no enhancement of neurotrophin-3 (NT-3) mRNA when examined by reverse transcription-polymerase chain reaction (RT-PCR). CONCLUSIONS: Activated retinal glial cells may produce BDNF which prevents retinal neuronal cell damage following injury.

Animals↗

PubMed1999

Comparison of telomerase and CD44 expression as diagnostic tumor markers in lesions of the thyroid.

The analysis of the tissue expression patterns of both the telomerase enzyme and the adhesion molecule CD44 has highlighted these molecules as potential tumor markers. In this study, the expression of these markers was analyzed in frozen tissue samples of the same human thyroid lesions, and the data were compared to evaluate their application to tumor diagnosis. The study analyzed 12 malignant specimens, including 5 papillary, 3 follicular, 2 anaplastic, 1 medullary, and 1 low-grade Hurthle cell carcinoma and 17 specimens from benign lesions, including cases of adenoma, hyperplasia, and Graves' disease. Telomerase expression was analyzed by assay of enzyme activity using the telomeric repeat amplification protocol and by reverse transcription-PCR detection of human telomerase reverse transcriptase (hTERT) mRNA. Nine of 12 (75%) malignant samples and the two Graves' disease samples were evaluated as positive for telomerase activity by the telomeric repeat amplification protocol assay. The presence of hTERT mRNA was detected in 8 (67%) of 12 malignant tissues and in 5 (29%) of 17 benign thyroid tissue samples. The expression of CD44 transcripts containing variant exons 7, 8, and 11 was evaluated by reverse transcription-PCR/Southern blot analysis. Of the 12 malignant samples, 9 (75%) included transcripts containing exon 7, 10 (83%) included transcripts containing exon 11, and 11 (92%) included transcripts containing exon 8. However, these CD44 exons were also present in transcripts in a high proportion of benign samples. Five (28%), 10 (59%), and 6 (35%) benign samples contained CD44 transcripts, including variant exons 7, 8, and 11, respectively. The measurement of telomerase activity proved to be the most specific for the detection of thyroid carcinoma in frozen tissue samples as a single analyte, but diagnostic accuracy was increased by the combination of telomerase and CD44 analyses.

Biomarkers, Tumor↗

PubMed1998

Clinical and cytogenetic remission induced by interferon-alpha in a patient with chronic eosinophilic leukemia associated with a unique t(3;9;5) translocation.

A patient with chronic eosinophilic leukemia and a unique complex chromosomal translocation 46,XY,t(3;9;5)(q25;q34;q33) who had elevated blood interleukin-5 is reported. Complete cytogenetic remission was induced by interferon-alpha after treatment failure with corticosteroids and cytotoxic drugs. Severe cardiopulmonary symptoms due to hypereosinophilia and thromboembolic complication improved dramatically in the first 6 months of interferon therapy. Since it is known that the gene encoding for interleukin-5 resides on the long arm of chromosome 5, it may be possible that the chromosomal translocation in our patient resulted in overproduction of this cytokine, and our findings may be helpful for understanding the pathogenesis of this disorder.

Adult↗

PubMed1998

Prediction of functional recovery and prognosis in patients with acute myocardial infarction by 123I-BMIPP and 201Tl myocardial single photon emission computed tomography: a multicenter trial.

123I-BMIPP [15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid] was developed for metabolic imaging with SPECT. A multicenter collaborative study was conducted on a large patient series to determine whether 123I-BMIPP and 201Tl myocardial SPECT are of use in predicting the prognosis and ventricular function after acute myocardial infarction (AMI). Patients with uncomplicated first AMI underwent resting 123I-BMIPP and 201Tl myocardial SPECT in the subacute phase after the onset of AMI. Of these, 167 patients who had been followed up for an average of 22 months were retrospectively reviewed to predict serious cardiac events and recurrent ischemia. In addition, the association between changes in radionuclide parameters and recurrent ischemia was investigated in Subgroup A (58 patients) who had repeated SPECT in the chronic phase. Furthermore, prediction of the ejection fraction (EF) was investigated in Subgroup B (94 patients) and Subgroup C (76 patients) in whom left ventriculography was performed at the time of discharge and 90 days or more after the onset, respectively. The prognosis was generally favorable, with 4 cases of cardiac death (2%), 3 of heart failure (2%), 4 of nonfatal reMI (2%), and 25 of recurrent ischemia (15%). The results of Cox multivariate regression analysis revealed a high probability of serious cardiac events in patients who were elderly (p = 0.04), who had 90% or more residual stenosis of the infarct-related artery (p = 0.09), and who had a high BMIPP defect score (p = 0.17). There was a high probability of recurrent ischemia in elderly patients (p = 0.10) who had multi-vessel disease (p = 0.03), but no association was found with radionuclide parameters in the subacute phase. In Subgroup A, however, the probability of recurrent ischemia tended to be high in patients with a large mismatch scorebetween 123I-BMIPP and 201Tl in the subacute to chronic phase. An important observation was that the extent of BMIPP defect was more strongly correlated with EF at the time of discharge and 90 days or more after the onset than the extent of Tl defect (r = -0.60 vs. r = -0.47, and r = -0.53 vs. r = -0.43, respectively). In addition, multiple regression analysis showed that parameters related to the BMIPP defect were also better predictive factors of EF both at the time of discharge and 90 days or more after the onset. In conclusion, resting 123I-BMIPP and 201Tl myocardial SPECT performed in the subacute phase of AMI were shown to be useful in predicting prognosis and ventricular function for patient management.

Aged↗

PubMed1998

Inhibitory effects of pentamethine trinuclear cyanine dyes on ADP/Fe2+-induced lipid peroxidation in rat liver mitochondria: changes in the mode of action with the hydrophobic nature of the dyes.

The effects of various pentamethine trinuclear cyanine dyes, each of which has three alkyl chains, on ADP/Fe2+-induced lipid peroxidation in rat liver mitochondria were examined. Although the dye having the shortest -C2H5 chains (tri-S-C2(5)) did not show any appreciable effect, the dyes having -C4H9 (tri-S-C4(5)), -C7H15 (tri-S-C7(5)), and -C12H25 (tri-S-C12(5)) chains significantly inhibited lipid peroxidation, the most potent inhibitory effect being observed with tri-S-C7(5). The mode of antiperoxidation effect of the dyes was dependent on the length of the alkyl chains. The relatively hydrophilic dye tri-S-C4(5) was suggested to scavenge radicals more efficiently at or near the membrane surface rather than in the interior of the lipid membrane, whereas the more hydrophobic dye tri-S-C7(5) was suggested to scavenge radicals efficiently in the membrane rather than at or near the membrane surface. The hydrophilic/hydrophobic balance of the dye was found to regulate the site of action of the dyes.

Adenosine Diphosphate↗

PubMed1998

[Individual variations in color vision and its molecular biology].

Individual variations in normal color vision and congenital red-green color vision defects in Japanese males were investigated using both psychophysics and molecular biology techniques. 1. Normal color vision. We studied 72 Japanese males who were diagnosed as having normal color vision using the Ishihara plates test and Nagel model I anomaloscope. The structure of the gene arrays of the X-linked L- and M-pigment genes was determined using quantitative PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism). We found the following variations of the number of M-pigment genes: 27 (38%) of these men had only one M-pigment gene, 29 (40%) had two, 13 (18%) had three and 3 (4%) had four. Two common polymorphisms were found at amino acid residue 180 of both L- and M-opsin, of the total 56 (78%) were Ser and the other 16 (23%) were Ala in the L-pigment and of the total 65 (90%) were Ala and the other 7 (10%) were Ser in the M-pigment. The Rayleigh match midpoints fell within the normal range, however there were two fairly distinct groups with consistent differences in each group. The mean values of the proportion of red in a mixture of red and green were 0.564 +/- 0.026 (mean +/- standard deviation). Correlation was found only between the Rayleigh match midpoint and the polymorphism at residue 180 of L-pigment. In order to estimate the variations of L/M cone ratio in the retinae the spectral sensitivities using heterochromatic flicker method were measured. Using the hypothesis that the luminosity function is proportional to the sum of L- and M-cone spectral sensitivity (k L (lambda) + M (lambda)), the constant k values were obtained. The k values for the subjects with Ser180 and Ala180 L-pigment were 1.89 +/- 1.44 and 1.85 +/- 1.02 respectively. Furthermore, in order to study the variation of information processing system, the spectral sensitivities for 1 degree, 200-ms test flash on a white background were measured. Using the hypothesis that the spectral sensitivity is proportional to the difference of L- and M-cone spectral sensitivity (L (lambda) - k' M (lambda)), the k' values were obtained. The k' values for the subjects with Ser180 and Ala180 L-pigment were 1.38 +/- 0.06 and 1.49 +/- 0.07 respectively. As a result, it was suggested that there are individual variations in both the L/M cone ratio and the color opponent system. 2. Congenital red-green color vision deficiencies. We studied the structure of the gene arrays of the X-linked L- and M-pigment genes and investigated the relationship between genotype and phenotype in 21 Japanese males comprising 4 protanopia, 6 protanomaly, 7 deuteranopia and 4 deuteranomaly. All of the protan subjects had 5' L-M fusion gene with/without the M gene. All of the deutan subjects had a normal L gene with/without 5' M-L fusion gene. Genotype agreed with phenotype in 8 of 10 protan subjects and 10 of 11 deutan subjects. Two of them were diagnosed as abnormal trichromatism in spite of having only one gene. One of them was diagnosed as dichromatism in spite of having two genes that encoded spectrally different pigments. As a result, it was felt that the diagnosis of dichromacy and abnormal trichromacy with an anomaloscope has limitations.

Asian People↗

PubMed1998

[Pitfalls in echocardiographic diagnosis of mitral bileaflet prolapse].

Preoperative echocardiography provides good planning information for successful repair of mitral valve regurgitation, but identifying the prolapse of both the anterior and posterior leaflets is sometimes difficult. To clarify the cause of this problem, preoperative echocardiographic findings and intraoperative observations of the prolapse were analyzed in 124 patients with non-rheumatic pure mitral regurgitation. In 48 patients with final diagnoses of bileaflet prolapse, 16 (33%) were considered to have only single leaflet prolapse before the operation. Anterior leaflet prolapse was overlooked in 14, and prolapse of either of its commissural segments was the least detectable by echocardiography. Chordal rupture was seen more in the posterior leaflet than in the anterior leaflet. Movement of the anterior leaflet may be influenced by a prolapsed and hypermobile posterior leaflet and/or regurgitant jet flow caused by the posterior leaflet prolapse.

Chordae Tendineae↗

PubMed1998

Telomerase activity in lesions of the thyroid: application to diagnosis of clinical samples including fine-needle aspirates.

The telomerase enzyme is capable of replacing telomeric DNA sequences that are lost at each cell division. It has been suggested that the function of this enzyme is necessary for cells to become immortal, and in concordance with this hypothesis, telomerase activity has been detected in malignant tumor cells, whereas the enzyme is inactive in normal somatic cells. The measurement of this activity in human tissue samples may have diagnostic value, and in this study, we examined whether such a measurement may be useful for the detection of malignant cells within the thyroid. Telomerase activity was assayed using the telomeric repeat amplification protocol and related to the histological diagnosis of thyroid biopsy tissue samples and of cells obtained from the thyroid by fine-needle aspiration (FNA). Extracts from 9 of 11 (82%) carcinoma biopsy tissue samples contained telomerase activity, whereas enzyme activity was detected in only 2 of 14 (14%) benign tissue sample extracts. These two positive cases were subsequently diagnosed as Graves' disease with severe lymphocytic infiltration. Five of six (83.3%) histologically confirmed carcinoma FNA samples were identified by using the telomeric repeat amplification protocol assay, and two samples considered to be suspicious by FNA cytology were also positive. Conversely, only 4 of 48 (8.3%) benign FNA samples had telomerase. These promising data indicate that this sensitive assay could become a useful adjunct to microscopic cytopathology in the detection of cancer cells in small tissue biopsies and in fine-needle aspirates of the thyroid.

Biopsy, Needle↗

PubMed1998

[A case of primary localized amyloidosis of the urinary bladder].

A case of primary amyloidosis of the bladder is reported. A 59-year-old man visited our hospital with a complaint of gross hematuria. Cystoscopy revealed several elevated lesions with yellowish surface accompanied by proliferated vessels at the posterior wall. Transurethral mucosal biopsy was performed. Histopathological diagnosis was a primary localized amyloidosis of AL type in the bladder. Systemic amyloidosis was clinically excluded. He is followed for 38 months without symptoms but mucosal lesions persisted.

Amyloidosis↗

PubMed1998

[Meige's syndrome associated with basal ganglia and thalamic functional disorders].

Magnetic resonance imaging (MRI) or single positron emission computed tomography (SPECT) or both were performed and the responses of surface electromyography (EMG) were examined in seven cases of Meige's syndrome. MRI or SPECT or both demonstrated lesions of the basal ganglia, the thalamus, or both in five of the cases. Surface EMG revealed abnormal burst discharges in the orbicularis oculi and a failure of reciprocal muscular activity between the frontalis and orbicularis oculi in all the cases. These findings suggest that voluntary motor control and reciprocal activity in the basal ganglia-thalamocortical circuits are impaired in Meige's syndrome. In addition, good responses were seen to clonazepam, tiapride and trihexyphenidyl in these cases. Therefore, we conclude that dopaminergic, cholinergic, and gamma-aminobutyric acid (GABA) ergic imbalances in the disorders of the basal ganglia and thalamus in Meige's syndrome cause control in the excitatory and inhibitory pathways to be lost, resulting in the failure of integration in reciprocal muscular activity and voluntary motor control. This failure subsequently causes the symptoms of Meige's syndrome.

Aged↗

PubMed1998

[Treatment outcome on 52 patients with 53 testicular germ cell tumors].

Between August 1983 and April 1996, 53 testicular germ cell tumors in 52 patients were treated at Toranomon Hospital. The average age of the patients was 36.1 years (range 21-89). The affected side was the right side in 24, left in 27 and bilateral in 1 case. Of the 53 tumors 34 (64.2%) were seminoma and 19 (35.8%) were non-seminomatous germ cell tumor (NSGCT). High ligation orchiectomy was performed in all cases. Of 29 stage I seminomas, post-operative adjuvant radiotherapy was performed in 6 cases prior to 1991. None of these tumors recurred. Two cases of relapses (8.7%) were found among the 23 stage I seminomas followed by surveillance. Of 8 stage I NSGCTs followed by surveillance, 4 (50.0%) tumors which contained embryonal carcinoma element and vascular invasion relapsed within 12 months after orchiectomy. A case of stage IIA seminoma was treated successfully by irradiation. Seven cases of stage II (3 seminomas and 4 NSGCTs) and 8 cases of stage III (1 seminoma and 7 NSGCTs) as well as cases of 6 stage I patients who developed relapse during surveillance were treated by VAB-6 chemotherapy. Of these 21 cases, 11 (52.4%) achieved complete response (CR) and 10 (47.6%) partial response (PR). Salvage surgery and/or additional chemotherapy was successful to bring the 10 PR cases into CR condition. One NSGCT patient, however, died of electrolyte imbalance during the maintenance chemotherapy for disease progression after achieving CR. All 34 patients with seminomas and 18 of the 19 with NSGCTs were alive without evidence of disease after a mean follow up period of 61.1 months (range 4-150 months).

Adult↗

PubMed1997

Study of the action of human salivary alpha-amylase on 2-chloro-4-nitrophenyl alpha-maltotrioside in the presence of potassium thiocyanate.

The degradation mechanism of a synthetic substrate, 2-chloro-4-nitrophenyl alpha-maltotrioside (CNP-G3), by human salivary alpha-amylase (HSA) was investigated by kinetic and product analyses. It was observed that the enzyme attacked the various CNP-maltooligosaccharides (CNP-G3 to CNP-G6) releasing free CNP. Addition of 500 mM potassium thiocyanate (KSCN) was also found to greatly increase the rates of CNP-release. It was the fastest with CNP-G3, and, in the presence of KSCN, was almost comparable to that of degradation of maltopentaose (G5). On the other hand, addition of KSCN decreased the rate of cleavage between glucan-glucan bonds in maltopentaose. Product analysis showed that KSCN addition altered the cleavage distribution which occurred 100% at the bond between CNP and G3, and that product distribution of free CNP was largely dependent on substrate concentration. Formation of CNP-G6, a larger product than the original substrate CNP-G3, was found to be present in the digest at high concentrations of substrate and in the presence of KSCN. Based on these results, a degradation pathway for CNP-G3 involving transglycosylation besides direct hydrolysis is proposed. The increase of the CNP-release by the addition of KSCN would result from a corresponding increase in the interaction between the CNP moiety and the corresponding subsite near the catalytic site, as well as the enhancement of the catalytic efficiency.

Chromatography, High Pressure Liquid↗

PubMed1997

Anti-tremor activity of talipexole produced by selective dopamine D2 receptor stimulation in cynomolgus monkeys with unilateral lesions in the ventromedial tegmentum.

The anti-tremor activity of talipexole (6-allyl-2-amino-5,6,7,8-tetrahydro-4H-thiazolo[4,5-d]azepine dihydrochloride, B-HT 920 CL2, Domin), a non-ergot dopamine D2 receptor agonist which possesses alpha 2-adrenoceptor agonistic and 5-HT3 receptor antagonistic properties, was examined in monkeys with a unilateral lesion in the ventromedial tegmentum. Talipexole dose dependently suppressed the tremor and had ED50 values of 34 micrograms/kg s.c. and 84 micrograms/kg p.o. The anti-tremor effect of talipexole occurred at much lower doses than that of an ergot dopamine receptor agonist, bromocriptine (2-bromo-alpha-ergocryptine mesilate, ED50; 2.5 mg/kg s.c.), and talipexole acted synergistically in combination with L-DOPA (3,4-dihydroxyphenylalanine). In ventromedial tegmentum-lesioned monkeys, anti-tremor doses of talipexole did not cause emetic behavior, but had sedative effects. Conversely, monkeys given bromocriptine exhibited oral movement, salivation and vomiting when anti-tremor effects were observed, but not marked sedative behavior at any of the doses investigated. During repeated administration of talipexole (a daily dose of 50 micrograms/kg s.c. for 21 days), the extent and duration of the anti-tremor effect did not change, but those of the sedative effect decreased gradually. The anti-tremor effect of talipexole was significantly suppressed by sulpiride, but not by SCH 23390 (7-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepine-7-ol) or yohimbine, while the sedative effect was inhibited by sulpiride and yohimbine. The main metabolites of talipexole had no anti-tremor or sedative effects. These results indicate that talipexole exerts its anti-tremor activity via selective dopamine D2 receptor stimulation.

Administration, Oral↗

PubMed1997

Idiopathic restrictive cardiomyopathy with diffuse perimyocytic fibrosis--a rare observation.

Idiopathic restrictive cardiomyopathy (RCM) is rare. Even today little is understood of its etiology or underlying mechanisms, and definitive diagnostic criteria are lacking. In this report, we describe a case of idiopathic RCM in a young Japanese woman who died while awaiting cardiac transplantation during the 5-year course of the disease. Rare pathologic findings of diffuse perimyocytic fibrosis were revealed at autopsy.

Adult↗

PubMed1997

[Transurethral microwave thermotherapy for benign prostatic hyperplasia].

BACKGROUND: We studied the clinical efficacy of transurethral microwave thermotherapy (TUMT) using Endotherm UMW system (OLYMPUS). METHODS: TUMT was performed in 28 patients with benign prostatic hyperplasia (BPH). Three patients of them were catheterized because of urinary retention. The treatment was performed in a single session for an hour. The urethral surface temperature was set at 39 degrees C, and the coolant flow of the urethral applicator (21 Fr balloon catheter) was set at 30 ml/min, to heat up the broad area of the prostate up to 45 degrees C. The clinical efficacy was evaluated by analyzing subjective responses, using the International Prostate Symptom Score (I-PSS) scale (S) and QOL score (L), and objective responses, using peak urinary flow rate (Qmax), average flow rate (Qave), residual urine volume and prostate volume following the treatment. RESULTS: At 24 weeks after the treatment, significant improvement were observed in S score (41%), L score (37%), Qmax (53%) and Qave (62%). Although there was no significant decrease in residual urine and prostate volume. The three patients, with a catheter indwelled because of urinary retention, were all free of the catheter within 4 weeks after the treatment. During and after the treatment, no severe adverse effects, including transient urinary retention needed for indwelling a catheter, was detected. CONCLUSION: A single session of TUMT by Endotherm UMW considered to be safe and useful for symptomatic BPH patients, even who are not indicated for transurethral resection of the prostate (TUR-P) because of underlying disorders.

Aged↗

PubMed1997

Growth inhibitory effect of interferon-beta is associated with the induction of cyclin-dependent kinase inhibitor p27Kip1 in a human gastric carcinoma cell line.

The effect of IFN-beta on cell growth and the mechanism of growth modulation was examined in human gastric carcinoma cell lines. IFN-beta inhibited the cell growth of TMK-1 cells, whereas it did not affect the growth of the other three cell lines (MKN-7, -28, and -45). The number of apoptotic cells in IFN-beta-treated TMK-1 cells was 2-fold the number of those in control TMK-1 cells, whereas the induction of apoptosis was not observed in IFN-beta-treated MKN-28 cells. IFN-beta enhanced the expression of cyclin-dependent kinase inhibitor p27Kip1 at mRNA and protein levels. The increased p27Kip1 bound preferentially to CDK6. The phosphorylation level of retinoblastoma protein in TMK-1 cells was reduced by IFN-beta treatment. IFN-beta did not affect the expression of cell cycle regulators in MKN-28 cells. These results suggest that the induction of p27Kip1 by IFN-beta might confer inhibition of cell growth, leading to subsequent apoptosis in TMK-1 cells.

Adenocarcinoma↗

PubMed1997

[Detection of cortical activities on eye movement using functional magnetic resonance imaging].

Cortical activity during eye movement was examined with functional magnetic resonance imaging. Horizontal saccadic eye movements and smooth pursuit eye movements were elicited in normal subjects. Activity in the frontal eye field was found during both saccadic and smooth pursuit eye movements at the posterior margin of the middle frontal gyrus and in parts of the precentral sulcus and precentral gyrus bordering the middle frontal gyrus (Brodmann's areas 8, 6, and 9). In addition, activity in the parietal eye field was found in the deep, upper margin of the angular gyrus and of the supramarginal gyrus (Brodmann's areas 39 and 40) during saccadic eye movement. Activity of V5 was found at the intersection of the ascending limb of the inferior temporal sulcus and the lateral occipital sulcus during smooth pursuit eye movement. Our results suggest that functional magnetic resonance imaging is useful for detecting cortical activity during eye movement.

Adult↗