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Biomedical subjects

K Ohara

Publications and source records attributed to K Ohara.

At least 109 records · Page 6Linked to original sources
PubMed1997

Three CAG trinucleotide repeats on chromosome 6 (D6S1014, D6S1015, and D6S1058) are not expanded in 30 families with schizophrenia.

Since 1991, more than five neuro-genetic disorders have been recognized to be caused by trinucleotide repeat expansions, and the list of such disease should grow. The diseases are characterized clinically by the phenomenon of anticipation, i.e., worsening of the disease phenotype in successive generations with increasing trinucleotide repeat expansion. The presence of anticipation in familial schizophrenia has been suggested. Several studies have provided supportive evidence that the suceptability locus for schizophrenia is on chromosome 6. Therefore, we analyzed three CAG trinucleotide repeat clones D6S1014, D6S1015, and D6S1058 on chromosome 6, which are polymolphic in 30 families with schizophrenia. No unusually, long alleles that would suggest abnormal expansion of more than 35 trinucleotide repeats were observed for these genes. Also, no statistically significant differences were found between the offspring and parental generations of affected subjects or between the affected and unaffected subjects in families with schizophrenia.

Adult↗
PubMed1997

Chest wall deformities and thoracic scoliosis after costal cartilage graft harvesting.

Donor-site complications, specifically chest wall deformities and thoracic scoliosis, occurring after harvest of costal cartilage grafts are presented and discussed. The cases of 18 patients (12 male and 6 female), who underwent costal cartilage grafts for microtia reconstruction from 1975 to 1993, were reviewed for donor-site complications using radiography and physical examination. Ribs from which costal cartilage had been harvested showed increased inward bowing on radiographs in 16 of 32 donor sites. The frequency of rib deformity in donor sites was 20.0 percent when cartilages were harvested from patients older than 10 years of age, whereas it was 63.6 percent in patients younger than 10 years old. This difference was statistically significant (p = 0.027, Fisher's exact test), although only 32 grafts were performed in 18 cases. The upper ribs demonstrate a higher incidence of deformity than lower ribs. Thoracic scoliosis was found in 4 of 16 cases. The biomechanical impact of these deformities was considered because of respiratory movement of the thorax and injury to the germinal growth center of the ribs. We recommend delaying costal cartilage grafts for as long as possible, leaving the costochondral junction intact to minimize chest wall deformity and thoracic scoliosis.

Adolescent↗
PubMed1997

Mechanism of vestibular adaptation of fish under microgravity.

In a space experiment, the adaptation of goldfish behavior during flight and readaptation after landing were investigated. Six goldfish (1 normal, 1 with otoliths removed on both sides, 4 with otoliths removed on one side) were flown in a fish package (F/P) of Aquatic Animal Experiment Unit (AAEU). The dorsal light responses (DLRs) of fish with otoliths removed were recorded after operation until launch and after landing. The behaviors of the fish were recorded with a video camera on Mission Elapsed Time (MET) Day-00, 02, 05, 08, 12. On MET Day-00, two fish with otoliths removed on one side showed flexion of body toward the operated side. These fish also showed rolling behavior toward the operated side. However, the body flexion disappeared on MET Day-05 or MET Day-08. No rolling behaviors were observed after that time. Five fish showed backward looping behaviors during the mission. Although the frequency of looping episodes decreased after MET Day-08, five fish still showed looping behavior on MET Day-12, that was the last day of video recording on orbit. In microgravity, visual system of fish did not seem to provide sufficient cues to prevent them from looping or rolling. After landing, no looping and rolling behavior was observed. However, the tilt angle of the DLR increased in the fish with otolith removed 5 month before launch but not in normal fish and those with otoliths removed 2 weeks before launch. These results suggest that the behavioral dysfunction and the adaptational process in space are dependent on vestibular inputs.

Adaptation, Physiological↗
PubMed1997

[Case report of coronary artery bypass performed on a patient implanted with a single-lead atrial triggered ventricular VDD pacemaker].

Single-lead atrial synchronized ventricular pacing using a floating atrial sensing electrode enables physiologic pacing in patients with complete atrioventricular block and normal sinus function. Open heart surgery performed on patient implanted with a single-lead atrial triggered ventricular VDD pacemaker is rarely reported. A 71-year-old male had been implanted with a single-lead VDD pacemaker because of Mobitz II atrioventricular block. He had a history of old myocardial infarction and diabetes mellitus. Coronary angiography revealed stenoses in the left main trunk and two main vessels. Bypass grafting of two coronary vessels under cardiopulmonary bypass was performed. Just before surgery, the pacemaker was reset to VVI mode at minimum pacing rate (50 beats per minute). During surgery, precautions were taken to ensure that the lead was not touched and that the position of the atrial electrode was not altered by atrial cannulation. After surgery, temporary VVI pacing at 90 beats per minute was conducted using a temporary ventricular pacing lead. However, this temporary lead was not absolutely necessary because the VVD pacemaker could be used. If a temporary lead was to be placed during surgery, placing it in the atrium to utilize the VDD pacemaker would be preferable because it would contribute to the cardiac function. The patient recovered uneventfully and was discharged one month after the surgery. This case demonstrates that special precautions different to those needed for a fixed electrode are required for a floating electrode placed in the atrium.

Aged↗
PubMed1997

[A successful surgical case report of acute aortic dissection involving entire sinus of Valsalva].

We successfully performed aortic root replacement for acute aortic dissection, Stanford type A involving the entire sinus of Valsalva, associated with acute anterior wall myocardial infarction and aortic valve insufficiency. A 57-year-old man was admitted complaining of chest pain. An emergency operation was performed after a perfusion catheter was inserted to 99% stenotic lesion of the left anterior descending artery (LAD) on the same day. The dissection extended to both ostia of the coronary arteries and disrupted all commissures of the aortic valve, resulting in severe prolapse of the aortic valve leaflets. Aortic root replacement was performed using a valved conduit. The left main coronary artery was reattached to the graft using interposition technique with a 8 mm diameter woven Dacron tube graft. In addition, the LAD and right coronary artery were bypassed using saphenous vein. The postoperative course was uneventful and the patient was discharged from hospital on the 35th postoperative day. Retaining no aortic sinus and adequate coronary artery reconstruction is important for surgical repair of aortic dissection involving the entire sinus portion of the ascending aorta.

Aortic Dissection↗
PubMed1997

[The waffle procedure (multiple incision of epicardium) with pericardiectomy for constrictive pericarditis].

Pericardiectomy is the only effective surgical procedure for constrictive pericarditis, but we have often experienced a lack of significant improvement of hemodynamic parameters, this being attributed to the presence of residual constriction. We have had two patients with constrictive pericarditis. In these patients, we decorticated the pericardium as usual, anterior to the bilateral phrenic nerves without cardiopulmonary bypass, and then, multiple longitudinal and transverse incisions were carefully made in the fibrous epicardium, avoiding the predicted course of major coronary branches and the myocardium. At the end of the procedure, the epicardial fibrous surface acquired a waffle-like appearance. With this maneuver, relief of constriction was achieved and the myocardium was able to reexpand, thus obtaining an adequate hemodynamic response. Our two patients recovered fully, and were discharged on the 18th and 19th postoperative day. They are presently free of clinical symptoms.

Aged↗
PubMed1996

Polymorphisms of dopamine D2-like (D2, D3, and D4) receptors in schizophrenia.

The result of most association studies and linkage analyses have suggested a negative association between schizophrenia and D2-like (D2, D3, and D4) receptor polymorphisms. Although the polymorphisms of the D2-like receptor in themselves may not account for the etiology of schizophrenia, they can contribute to the severity of the symptoms. Thus, we studied the associations between the polymorphisms and their combinations, and the vulnerability of schizophrenics. Fragments of the D2-like receptor genes were amplified by means of the polymerase chain reaction, and the polymorphisms were identified by the restriction fragment length polymorphism and single-stranded conformation polymorphism methods. There were no statistically significant differences in the polymorphisms and their combinations between schizophrenics and controls. Schizophrenics with D4E1(A1/A2), which contains 2 and 1 tandem repeats of a 12-base-pair sequence in exon 1, had a lower total positive symptom score before medication than schizophrenics with D4E1(A1/A1). There was no association between the polymorphisms and negative symptoms.

Adult↗
PubMed1996

Effect of Prograf (FK506) on spermatogenesis in rats.

Prograf (FK506) was given to male mature rats in a daily subcutaneous dose of 1 or 3 mg/kg/day for 2 weeks to investigate its effect on spermatogenesis. Prograf dose-dependently sperm counts and motility, but did not affect testosterone level in the serum of rats. Histopathologically, there were no abnormal changes in the testis, seminal vesicle or prostate in any rats dosed with Prograf, but intra-ductal eosinophilic globules, probably degeneration of the sperm cells, were observed in the epididymis of the 3 mg/kg/day group. Sperm counts and motility returned to the control levels after stopping of the drug. The results indicate that Prograf decreased sperm counts and motility through direct action on the sperm in the epididymis, but not the production of sperm in the testis. Cyclosporine A (CsA) was used as the reference drug in the present study. Thirty mg/kg/day of CsA also decreased sperm counts and motility, and stopping of the drug led to the recovery of these changes. The males dosed with Prograf for 2 weeks were mated with non-dosed females to investigate its effect on the fertility potential of the males. Prograf did not affect copulation or fertility index, but a decrease in the number of live fetuses associated with implantation loss was observed in the 3 mg/kg/day group. The changes were considered to be due to the decrease of sperm counts and motility, although 1 mg/kg/day of Prograf, 5-10 times the clinical dose, did not affect any fertility parameters including implantation index.

Animals↗
PubMed1996

Daily rhythm of serum melatonin in patients with dementia of the degenerate type.

The daily rhythm in serum melatonin levels was measured in patients with dementia of the degenerate type (Alzheimer's disease, Pick's disease and senile dementia of the Alzheimer type) by radioimmunoassay. Thirteen patients (age: 69.0 +/- 8.0 years, mean +/- S.D.) were studied. All patients were hospitalized at the time of the study and had a history of sleep-wake disturbances, nocturnal wandering and/or delirium. We also studied 13 age-matched healthy control subjects (control group 1), ten young adults (control group 2), and nine hospitalized patients without dementia (control group 3). Two subjects in the control groups showed no measurable changes in melatonin level throughout the day, while the other 30 control subjects exhibited a clear daily rhythm with the peak concentration occurring during the night. On the other hand, four out of the 13 patients with dementia did not show any melatonin rhythm. Two of the demented patients who did not exhibit melatonin rhythm displayed clinical symptoms of rhythm disorders. One out of the nine patients with melatonin rhythm presented with clinical symptoms, such as delirium and sleep-wake disturbance. Our results suggest that the probability of absent melatonin rhythm is higher in demented patients compared with subjects without dementia. However, a lack of melatonin rhythm is not always associated with symptomatic rhythm disorders. Since the melatonin rhythm reflects that of the suprachiasmatic nucleus, it follows that the SCN function of the patients having a history of rhythm disorders was not always severely damaged.

Aged↗
PubMed1996

Impact of biological clearance on tumor radioresponsiveness.

PURPOSE: To determine the capacity of biological clearance in tumor regression following radiotherapy by using metastatic brain tumors as a clinical model in which mechanical clearance is negligible. METHODS AND MATERIALS: Thirty-eight tumors (19 nonsmall cell lung cancer, 11 small cell lung cancer, and 8 nonlung cancer) in 23 patients were followed with computed tomography (CT) scans over 3 months or more following initiation of radiotherapy, with doses ranging between 34 and 66 Gy. The tumor regression rate (RR; mm3/day), which represented the capacity of biological clearance, was calculated for each CT observation period. The complete response (CR) rate was calculated. The relationship between RR and tumor diameter was determined with regression analysis in conjunction with the pattern of contrast enhancement and the type of primary disease. The change of the RR also was examined. RESULTS: The CR rate was 60.5% for the total group; it was lower for ring-enhanced tumors (41.7%) than diffusely enhanced tumors (69.2%), which included mostly small cell lung cancer metastases. The RR correlated significantly with the tumor diameter (D), with a regression curve of exponential function (RR = 0.035 *D2.5). The RR varied widely and was rather large until 40 days following initiation of radiotherapy, especially for the subgroups of diffusely enhanced tumors and the small cell lung cancer tumors, and became rather constant thereafter. CONCLUSION: A tumor diameter exponent in the regression curve of smaller than 3.0 indicates that the larger the tumor volume is, the smaller the capacity of biological clearance. The capacity of biological clearance also is dependent on vascularity and cellularity of the tumor components expressed by the pattern of contrast enhancement.

Adult↗
PubMed1996

The genes encoding the 5HT1D alpha and 5HT1D beta receptors are unchanged in patients with panic disorder.

To determine the serotonergic function in panic disorder, sequencing of the genes encoding the 5HT1D alpha and 5HT1D beta receptors was carried out. The genes for the 5HT1D alpha and 5HT1D beta receptors were amplified by polymerase chain reaction and sequenced by the dideoxy method. Some patients have both nucleotides C and T at position 1080 in 5HT1D alpha receptor gene; however, both of them code the same amino acid, asparagine. The 5HT1D beta receptor gene had a substitution from GCA276 to GCG276, not only panic disorder but also in controls; however, this substitution does not change the corresponding amino acid, alanine92.

Adolescent↗
PubMed1996

Preoperative radiotherapy and surgery for advanced thymoma with invasion to the great vessels.

From 1983 to 1994, 12 advanced thymomas with invasion to the great vessels were initially treated by irradiation (mean dose, 18.3 Gy) and subsequent surgical resection. In nine patients, complete resection was possible by concomitant resection of the surrounding tissues, mainly pericardium and/or brachiocephalic vein. Histologically, all tumors showed prominent fibrosis. Ten patients also received postoperative radiotherapy (mean dose, 42.3 Gy). Tumor-related deaths occurred in only two patients; one who did not receive postoperative irradiation 21 months and one who had viable cells at the surgical margin 10 months after operation. However, there were also 2 patients who died of respiratory failure due to operation and/or irradiation, one 45 days and the other 7 years after the treatment. Preoperative radiotherapy could facilitate complete resection of the advanced thymomas. The prognosis of the patients treated with preoperative radiotherapy seemed fair if followed by adequate resection and subsequent irradiation.

Adult↗
PubMed1996

Intact 5-HT2A receptor exons and the adjoining intron regions in schizophrenia.

Genes that regulate serotonergic (5-HT) systems may underlie the etiology of schizophrenia. In this study the gene encoding the 5-HT2A receptor in schizophrenics and healthy controls was examined. First, we sequenced all exons and the flanking introns of the 5-HT2A receptor gene in 10 schizophrenics and 10 controls. The substitution of C for T at position 102 in exon, which had been reported by Warren et al. (1993), was confirmed. Restriction fragment length polymorphism (RFLP) analysis revealed no association between polymorphism and schizophrenia. There was no association between the polymorphism and subdiagnosis, family history, age of onset, amounts of antipsychotics, or positive and negative symptoms before or after medication. Other polymorphisms in the gene were screened in 100 schizophrenics by the single-strand conformation polymorphism method, but none was found. Our results suggest that an abnormality in the 5-HT2A receptor gene in schizophrenia is unlikely.

Adult↗
PubMed1996

Clearance of parenchymal tumors following radiotherapy: analysis of hepatocellular carcinomas treated by proton beams.

Clearance of a parenchymal tumor following radiotherapy was determined by using follow-up CT scans of 18 hepatocellular carcinoma tumors treated with focused proton beams. Regression analysis of the daily decrement (DD) and the diameter (D) of a tumor mass in each CT observation interval, DD = a*Db, showed that the exponent b was 3.0 or larger in early periods and 2.0 or smaller in late periods. This suggests that the clearance depends initially on the tumor volume, subsequently on the tumor surface area, and then it becomes much more moderate, possibly due to radiation damage to the parenchymal tissues.

Aged↗
PubMed1996

A new surgical technique for postaxial polydactyly of the foot.

A new technique for the treatment of the most common type of postaxial polysyndactyly of the foot is presented. The technique employs four local flaps and a skin graft from the pedal area. The outermost skeletal elements and nail tissue were excised, while the fourth interdigital commissure was deepened. This differs from historical techniques of desyndactylization in the hand that have been applied to surgery in the foot. The new technique is characterized by minimal waste of tissue from the outermost toe with preservation of the dominant fifth toe.

Abnormalities, Multiple↗