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Biomedical subjects

K Ohara

Publications and source records attributed to K Ohara.

At least 91 records · Page 5Linked to original sources
PubMed1998

Changes of monoamines in post-mortem brains from patients with diffuse Lewy body disease.

1. In the present study, we measured the concentrations of 5-hydroxytryptamine (5-HT), norepinephrine and dopamine in post-mortem brains from five patients with diffuse Lewy body disease (DLBD), in comparison with five brains from patients with Alzheimertype dementia (ATD), and five brains from normal controls. 2. They were measured by means of high-performance liquid chromatography fluorometric detection. 3. Compared with the ATD and normal control brains, the DLBD ones showed decreased concentrations of 5-HT, norepinephrine and dopamine in the putamen, and lower 5-HT and norepinephrine concentrations, and almost equal dopamine ones in the neocortex.

Aged↗
PubMed1998

Cerebral ventricle-brain ratio in monozygotic twins discordant and concordant for schizophrenia.

1. Several studies on monozygotic twins discordant for schizophrenia showed that the cerebral ventricle-brain ratio (VBR) was larger in the twins with schizophrenia, as compared with the corresponding normal twins. 2. The results suggest that the difference of the VBR of the discordant twins was larger than that of the concordant twins of schizophrenia. 3. The authors studied the VBR in four monozygotic twin pairs discordant and four monozygotic twin pairs concordant for schizophrenia by computerized tomography. 4. In the discordant twins, all pairs showed that the VBR of the normal twins was smaller than that of the corresponding twins with schizophrenia. 5. The difference of the VBR of the discordant twins and that of the concordant twins of schizophrenia was not statistically different using Mann-Whitney U test. 6. The preliminary results suggest that the VBR enlargement in schizophrenia is not genetically controlled in monozygotic twins either discordant or concordant for schizophrenia. 7. In monozygotic concordant twins, the brain pathology may be heterogeneous.

Adolescent↗
PubMed1998

Basal cell carcinoma with neuroid type nuclear palisading: a report of three cases.

Nuclear palisading is a characteristic feature which is typically seen in neural tumours such as neurilemmoma, and also in some other tumours. We report here three patients with basal cell carcinoma who showed histological patterns similar to nuclear palisading. To our knowledge, this is the first such case report in the medical literature; we apply the term 'neuroid-type nuclear palisading' to these cases. In our patients, the spindle-shaped tumour cells were tightly packed and the nuclei were arranged uniformly to form this rare feature.

Aged↗
PubMed1998

Radioresponse of thymomas verified with histologic response.

Patterns of radiologic response of 10 thymomas treated by preoperative radiotherapy (RT) (18-20 Gy/2 weeks) were determined in conjunction with histologic response. Changes in tumor volume were evaluated with CT scans obtained 5 to 36 days before and 14 to 24 days after the initiation of RT and before surgery. The extent of tumor volume reduction (TR) varied widely (40-78%), while the mean daily volume decrement expressed as a percentage of the pre-RT tumor volume correlated significantly with the pre-RT tumor volume. Histologically, the tumors, all of which were resected 17 to 33 days after RT initiation, generally consisted of predominant fibrous tissues, rare necrotic foci, and few epithelial cells. The TR did not correlate with pre-RT tumor volume, observation period, histologic subtype, or quantity of remaining epithelial cells. The TR of thymomas does not predict RT impact on tumor cells but does reflect the quantity of inherent tumor stroma.

Adult↗
PubMed1998

Study of a patient referral system in the Republic of Honduras.

The first nationwide study on a patient referral system was conducted in Honduras. It covered all 25 public hospitals (six National, five Regional and 14 Area Hospitals) and 24 major health centres. Based on 46,739 reviews of patient records, 226 'received referral' and 1072 'sent referral' cases were analyzed by age and sex of the patient, diagnosis on referral, institution from or to which the case was referred, use of proper referral form, and reception of reply for referrals. At the same time, the study team supervised the function of the registry and management of patient records at each institution. The average referral rate by the level of health facility was 15.8% at National, 4.0% at Regional, 2.8% at Area Hospitals, and 0.8% at health centres. The referral rate was observed to be higher when institutional managers emphasized the importance of the referral system. Only 1.4% of referrals received a reply from upper level institutions. The most common cases for referral were neurological at National, obstetric at Regional and respiratory cases at Area Hospitals. The use rate of the standard referral form was 70 to 80% at hospitals and 60% at health centres. There was no norm to duplicate referral letters for record keeping. The patient referral system has not developed satisfactorily in Honduras. The main problems were: 1) low referral rate at all levels of institution, 2) evident by-pass phenomenon at intermediate hospitals, 3) inadequate health information system for patient referral, and 4) misunderstanding of the terminology of referral by health personnel. The following recommendations were made: guarantee of essential health services at peripheral institutions, development of an effective information system for patient referral, facilitation of frequent reply for referrals, elaboration of referral case discussion between institutions, patient education on proper use of health facilities, and restructuring the health service network in the two major cities.

Community Health Centers↗
PubMed1998

Photosensitivity reactions caused by lomefloxacin hydrochloride: a multicenter survey.

The photosensitivity effect of lomefloxacin hydrochloride (LFLX) was investigated in terms of patient background factors (sex, age, underlying disease, complications, history, occupation, and residential condition, etc.), treatment factors (daily dosage of LFLX, duration of treatment, total dose, concomitant drugs, and previous medication, etc.), and correlations among them. In 100 institutions throughout Japan, 4,284 patients were enrolled over a period of 2 years, beginning in October 1991, avoiding the accumulation of patients in any specific season. Since 8 patients did not visit again after enrollment, the clinical records of 4,276 patients were analyzed. Photosensitivity in 44 patients was found (1.03%), but the symptoms in most patients were not severe and improved after discontinuation of LFLX treatment. The photosensitivity reaction was more prevalent in patients who were 60 years of age and older with concomitant diseases and complications, in patients treated with a total amount of 20 g and more of LFLX for 30 days or longer, and in patients with a history of previous treatment with quinolone drugs. Although the incidence and degree of the photosensitivity reaction vary significantly among new quinolone drugs, every quinolone drug is potentially phototoxic. In particular, long-term use of LFLX should be avoided, and patients taking LFLX should be advised to abstain from prolonged exposure to sunlight.

Adolescent↗
PubMed1998

Polymerase chain reaction and immunohistochemistry frequently detect occult melanoma cells in regional lymph nodes of melanoma patients.

AIMS: To evaluate immunohistochemistry and reverse transcriptase polymerase chain reaction (RT-PCR) for melanoma associated antigens (MAA) in detecting occult melanoma cells in lymph nodes which were missed on routine pathology. METHODS: Occult melanoma cells were sought in 436 lymph nodes from 32 patients with cutaneous melanoma of the lower extremities by immunohistochemistry using the melanoma specific antibody HMB-45. The detection sensitivity of routine histology, immunohistochemistry, and RT-PCR was also compared in 23 lymph node samples from six patients. RESULTS: Immunohistochemistry showed that 15 of 24 patients (62.5%) who had no detectable metastasis by routine histology had at least one lymph node containing HMB-45 positive cells, mostly seen singly in the medullary sinus. No difference was found in known clinicopathological prognostic factors and recurrence rates between the two groups of patients with and without occult HMB-45 positive cells. RT-PCR analyses showed that the nested PCR for tyrosinase was more sensitive than a combination of single round PCR for five different MAA, including tyrosinase, MART-1/Melan A, Pmel-17, TRP-1, and TRP-2, detecting tyrosinase mRNA in six nodes which were negative by HMB-45 immunohistochemistry. CONCLUSIONS: Immunohistochemistry + RT-PCR is more sensitive than routine histology in detecting occult melanoma cells in lymph nodes. The nested PCR for tyrosinase should be used in future studies investigating the prognostic significance of such lymph node micrometastases.

Antigens, Neoplasm↗
PubMed1998

[Radiotherapy: a significant treatment option in management of prostatic cancer].

In the management of patients with localized prostate cancer, both radical prostatectomy and radiotherapy are shown in the U.S. to be equally effective to control a local disease but associate with different types of toxicity. Therefore, both treatments are recommended for patients to choose freely. Recently, mainly in western countries, radiotherapy has achieved technological innovation so as to increase target tumor doses and to decrease the volume and dose of peritumoral normal tissues, by which the treatment outcome is further improved. Major innovative techniques include three-dimensional conformal radiotherapy (3D CRT) and a high dose-rate (HDR) brachytherapy system. Three-D CRT focuses radiation on the tumor through multiple portals minutely tailored to the tumor volume determined by computed tomography, in conjunction with a sophisticated treatment planning system. A HDR brachytherapy system provides high-tech interstitial radiotherapy; a remote afterloading system precludes radiation exposure of hospital workers and a computer-controlled source-scanning system enables optimization of dose distribution. In order to provide a variety of effective treatment options for Japanese patients, radiation oncologists must master these techniques in practice, in cooperation with urologists.

Aged↗
PubMed1997

Cataract development induced by repeated oral dosing with FK506 (tacrolimus) in adult rats.

FK506 (tacrolimus), a potent immunosuppressant, is used for inhibiting allograft rejection in the organ transplantation field. In a preclinical toxicity study in rats, FK506 induced various toxicities, including renal and pancreatic injuries. One of these toxic findings was cataract, and we have found that cataract appeared in rats dosed orally with FK506 for 13 weeks and more. Therefore, to better elucidate the onset mechanism of FK506-induced cataract, we measured biochemical parameters, such as sorbitol, Na,K-ATPase and glutathione in the lens of rats. Rats were dosed with FK506 in oral daily doses of 0.2, 1 or 5 mg/kg for 13 weeks, the lowest dose of which approximated the expected clinical dosage. Cataract developed in the 5-mg/kg/day group, with an incidence of 25%, whereas no cataract formation was observed in the 0.2- or 1-mg/kg/day groups. Five mg/kg/day led an increase of sorbitol and a decrease of reduced type glutathione, but did not affect Na,K-ATPase activity of the lens. FK506 is known to have diabetogenicity mediated through pancreatic injury, which appears as vacuolation of islet cell in rats. Five mg/kg/day of FK506 induced an elevation of blood glucose associated with glucose intolerance, and decrease of both basal insulin level and insulin content in the pancreas, and the changes were in parallel with the cataract development in the present study. On the other hand, diabetic parameters did not change in the 0.2- or 1-mg/kg/day groups. These observation suggest that diabetes developed in the rats dosed with 5 mg/kg/day of FK506. Coadministration of a novel aldose reductase inhibitor, Zenarestat, at an oral dose of 50 mg/kg/day resulted in a reduction of incidence of the FK506-induced cataract and a decrease of sorbitol levels in the lens when compared to that in the lens of rats dosed with 5 mg/kg/day of FK506. These results suggest that FK506-induced cataract in rats is due to an accumulation of sorbitol in the lens, secondary to the diabetogenic effect of FK506. FK506 treatment at the doses of 0.2 and 1 mg/kg/day neither affected parameters indicative of diabetes nor induced cataract in rats, suggesting that the cataract would not develop with FK506 if diabetic parameters were kept under control.

Administration, Oral↗
PubMed1997

Exclusion of five trinucleotide repeat (CAG and CCG) expansions in 17 families with schizophrenia.

Trinucleotide repeat expansion diseases are characterized by anticipation. Several studies suggested the anticipation in schizophrenia. We studied five novel trinucleotide repeats identified by Li et al in a human brain cDNA library in 100 unrelated control subjects, and 57 subjects in 17 families with schizophrenia. The CTG-B43 and B45d, and CCG-A3 were not polymorphic in any unrelated control subjects or subjects with familial schizophrenia. The CTG-A4 had two alleles and the CTG-B1 three alleles. The two clones were not expanded in subjects with familial schizophrenia or unrelated healthy controls. There was no difference in allele frequency between unrelated control subjects and subjects in the families with schizophrenia. The allele frequencies in unaffected and affected subjects in the families with schizophrenia were not significantly different. There was no difference between the offspring and parental generations of affected subjects in the families with schizophrenia. The results suggest the exclusion of the five trinucleotide repeat expansions in the 17 families with schizophrenia.

Adolescent↗
PubMed1997

Anticipation and imprinting in schizophrenia.

Anticipation, i.e., a decrease in the age of onset and/or an increase in the severity of a disease in subsequent generations, and imprinting, i.e., different modes of parental transmission, have been suggested in trinucleotide repeat amplification diseases. The purpose of this study was to determine if anticipation and imprinting are associated with familial schizophrenia. Two generations of 49 schizophrenics from 24 families were studied. Ages of onset, numbers hospitalized, diagnostic subclasses of schizophrenia, amounts of antipsychotics, positive symptoms, negative symptoms, treatment resistance, and clinical course ratings, were compared between the two generations. The age of onset was significantly lower in the offspring generation, although there was no difference in the severity between the two generations. The negative symptom scores and clinical course scores in the offspring generation for paternal transmission were significantly higher than those for maternal transmission. Our results suggest the presence of imprinting and anticipation in schizophrenia.

Adolescent↗
PubMed1997

Detection of DNA lesions induced by chemical mutagens by the single cell gel electrophoresis (Comet) assay. 1. Relationship between the onset of DNA damage and the characteristics of mutagens.

We evaluated the relationship between the onset of DNA damage and the characteristics of 5 model chemical mutagens with the single-cell gel electrophoresis (SCG) assay using L5178Y mouse lymphoma cells. We treated the cells with each chemical for 3 h and sampled them 0, 21, and 45 h after treatment. DNA damage induced by UV mimetic mutagens MMS and MNU, and X-ray mimetic mutagen BLM was observed just after treatment, crosslinking agent MMC-induced DNA damage was detected 21 h after treatment, and 6-MP as an inhibitor of DNA synthesis did not induce DNA damage at any sampling time. These results suggest that the SCG assay detects DNA lesions just after treatment with UV and X-ray mimetic mutagens, but needs a waiting period after treatment with crosslinking agents.

Animals↗
PubMed1997

Radiation tolerance of cirrhotic livers in relation to the preserved functional capacity: analysis of patients with hepatocellular carcinoma treated by focused proton beam radiotherapy.

PURPOSE: To determine the preserved functional capacity of the liver as a probable determinant of radiation tolerance in patients with cirrhosis and hepatocellular carcinoma, who underwent proton beam radiotherapy. MATERIALS AND METHODS: We reviewed computed tomographic (CT) scans of 26 patients with cirrhosis and hepatocellular carcinoma during a period of 12-27 months after proton beam radiotherapy. Tumors were treated with focused proton beams with target doses of 140-186 TDF (time, dose, and fractionation). We measured the degree of hypertrophy of the untreated liver volume by measuring the total liver volume and the treated liver volume which was radiologically identified on contrast-enhanced CT scans. The risk of radiation-induced liver failure was estimated using the prediction score (PS) originally used for estimating posthepatectomy liver failure, substituting the planned treated liver volume for the resection liver volume. RESULTS: The degree of hypertrophy ranged from -19% to 51%, and was significantly positively correlated with the ratio of the planned treated liver volume to the functional liver volume. The PS agreed well with observed radiation tolerance in 21 patients, but underestimated the tolerance in 5. This underestimation was diminished when the PS was recalculated using the identified untreated liver volume in lieu of the planned untreated liver volume. CONCLUSION: As in surgical treatment, radiation tolerance of the cirrhotic liver after focused treatment is closely related to the preserved functional capacity of the identified untreated liver volume, which shows compensatory hypertrophy following radiotherapy.

Aged↗
PubMed1997

Serotonin2A receptor gene polymorphism in mood disorders.

Genes that regulate the serotonin (5-HT) system including 5-HT receptors may be involved in mood disorders. We studied 5-HT2A receptor exons and the adjacent intron regions in 102 patients with mood disorders (71 depressive disorders and 31 bipolar disorders). In 34 mood disorder cases, the gene encoding the 5-HT1A receptor had been sequenced, but no disease-specific polymorphism was found. The substitution of C for T at position 102 in exon 1, which had been reported by Warren et al., was confirmed. The corresponding amino acid, serine, did not change. The allele frequency of C [corrected] at position 102 was significantly higher in patients with depressive disorders than in those with bipolar disorders and healthy control subjects. Furthermore, the mean age of onset in the patients heterozyous for the T and C alleles was lower than that in those homozygous for the C allele. No other polymorphism in the gene was found.

Adolescent↗
PubMed1997

Analysis of the 5'-flanking promoter region of the 5-HT2A receptor gene in schizophrenia.

We studied the 5'-flanking promoter region comprising positions -1441 to +128 of the 5-HT2A receptor gene in 95 schizophrenics and 100 unrelated normal control subjects. The genes encoding the 5-HT2A receptor exons and the adjoining introl regions had already been studied in these subjects, but no disease specific polymorphism was found (Ishigaki et al., 1996). The DNA fragments were amplified by means of the polymerase chain reaction (PCR), and then analyzed by the single-stranded conformation polymorphism (SSCP) and sequencing methods. One patient had a substitution, from A to G, at position -668, and a 5 nucleotide deletion of TACTT at positions -646 to -642, however, the patient also had a normal sequence on the other allele. SSCP analysis showed that the other schizophrenics and the control subjects did not have any polymorphism in the 5'-flanking promoter region of the 5-HT2A receptor gene.

Adult↗