Biomedical subjects

K Ohara

Publications and source records attributed to K Ohara.

532 records · Page 30Linked to original sources

PubMedDate not supplied

Age-related changes of human lens epithelial cells in vivo.

We examined the density and morphology of lens epithelial cells (LECs) in vivo in a group of normal volunteers and cataract patients by using a newly developed noncontact specular microscope. There was a statistically significant decrease in the cell density of LECs in a group of cataract patients over the age of 80 years. The coefficient of variation of the cell area and the number of large black spots that were observed in the enhanced specular images were not related to aging or cataract formation. Our data indicate that the cell density of LECs decreases after reaching the age of 80, but cataract formation does not affect the cell density or the coefficient of variation of the cell area until the age of 80.

Adolescent↗

PubMedDate not supplied

Benefits of combining radiotherapy with aggressive resection for stage IV gallbladder cancer.

BACKGROUND/AIMS: The efficacy of combining resection and radiation in the management of advanced gallbladder cancer has not yet been defined. In this study, effects of combining radiation therapy on survival, local control and the pattern of recurrences were analyzed as a retrospective review. METHODOLOGY: From October 1976 to May 1996, 85 patients with stage IV (pTNM) gallbladder cancer underwent various aggressive resection modalities in our institute, including 34 liver resections, 30 hepatopancreaticoduodenectomies. Intra-operative, external or intracavitary radiation therapy was supplemented to resection in 47 patients. RESULTS: The 30-day operative mortality rate was 5.9% and the overall 5-year survival rate of stage IV disease patients was 6.3%; 3 patients are living well more than 6 years after surgery. Adjuvant radiotherapy yielded a significantly (p=0.0023) higher 5-year survival rate (8.9%) than resection alone (2.9%). The local control rate was significantly (p=0.0467) higher in the adjuvant radiation group than in the resection alone group (59.1% vs. 36.1%). However, there was no statistical difference in the frequency of distant metastasis between the two groups. Significant improvement (p=0.0028) of long-term survival was exhibited when radiation was used appropriately on patients with microscopic residues only. Those with macroscopic or without microscopic residues failed to improve. The 5-year survival rate and median survival time of patients receiving adjuvant radiation therapy for microscopic residues were 17.2% and 463 days, respectively. CONCLUSIONS: Adjuvant radiation therapy following aggressive resection, in certain circumstances, improves prognosis with acceptable operative mortality for stage IV gallbladder cancer.

Adenocarcinoma↗

PubMedDate not supplied

Familial dementia with Lewy bodies (DLB).

We report a rare familial case of dementia with Lewy bodies (DLB). The patient was a man who died at the age of 51. His parents were first cousins. Among three siblings, two were diagnosed as probable cases of DLB, and one was a possible case, according to the clinical diagnostic criteria of the consortium on DLB. Following the patient's autopsy, he was found to have had DLB without neurofibrillary tangles or senile plaques (pure form of diffuse Lewy body disease). His other siblings have been followed for more than ten years. Although these patients with familial DLB displayed clinical variability, all three siblings showed progressive dementia of early onset and progressive language disorder with paraphasia and difficulty in finding words. Psychotic features were also seen in the three siblings. The patient's sister showed compulsive behavior, and the other two siblings showed symptoms of parkinsonism. Neuropathologically, in addition to the usual neuropathology of DLB, the autopsy findings showed numerous small spheroids in the stratum pyramidale from the subiculum to CA1 of the hippocampus. Significant neuronal loss in CA2-3 of the hippocampus was detected. Axonal flow disturbance may be involved in the hippocampal formations of this incidence of familial DLB.

Cerebral Cortex↗

PubMedDate not supplied

Utility of serum CA 19-9 monitoring in preoperative radiotherapy for pancreatic cancer.

BACKGROUND/AIMS: Pancreatic cancer is extremely refractory even to aggressive treatments including surgery, resulting in early metastasis and/or local recurrence. We investigated changes in serum tumor marker CA 19-9 levels during preoperative radiotherapy in conjunction with initial treatment failure. METHODOLOGY: Twenty-three patients presenting with localized disease and an increased serum CA 19-9 level, who were slated to undergo pancreatectomy and/or intraoperative radiotherapy following preoperative radiotherapy were reviewed. CA 19-9 response, the ratio of post-radiotherapy level before laparotomy to pre-radiotherapy level, was analyzed in relation to disease-control time and survival. RESULTS: Eleven patients revealed metastasis at restaging or laparotomy; 12 patients (52%) completed aggressive treatments. Initial failure was identified at the liver (52%), peritoneum (52%), or local site (26%) with a median disease-control time of 91 days; 7 patients showed combined failure. All but 1 patient died of cancer with a median survival time of 264 days. CA 19-9 response (range: 0-1185%) did not correlate with disease-control time or survival; 8 progressive-disease patients (> 140% response), however, showed significantly shorter disease-control time than 15 nonprogressive-disease patients (< or = 140% response). CONCLUSIONS: CA 19-9 monitoring is useful in preoperative radiotherapy for identifying patients who will not benefit by succeeding aggressive treatments by predicting early metastasis.

Adult↗

PubMedDate not supplied

Preliminary estimation of minimum target dose in intracavitary radiotherapy for cervical cancer.

PURPOSE: In intracavitary radiotherapy (ICRT) for cervical cancer, minimum target dose (Dmin) will pertain to local disease control more directly than will reference point A dose (D(A)). However, ICRT has been performed traditionally without specifying Dmin since the target volume was not identified. We have estimated Dmin retrospectively by identifying tumors using magnetic resonance (MR) images. MATERIALS AND METHODS: Pre- and posttreatment MR images of 31 patients treated with high-dose-rate ICRT were used. ICRT was performed once weekly at 6.0 Gy DA, and involved 2-5 insertions for each patient, 119 insertions in total. Dmin was calculated arbitrarily simply at the point A level using the tumor width (W(A)) to compare with D(A). W(A) at each insertion was estimated by regression analysis with pre- and posttreatment W(A). RESULTS: Dmin for each insertion varied from 3.0 to 46.0 Gy, a 16-fold difference. The ratio of total Dmin to total DA for each patient varied from 0.5 to 6.5. Intrapatient Dmin difference between the initial insertion and final insertion varied from 1.1 to 3.4. CONCLUSION: Preliminary estimation revealed that Dmin varies widely under generic dose prescription. Thorough Dmin specification will be realized when ICRT-applicator insertion is performed under MR imaging.

Adult↗

PubMedDate not supplied

Exfoliative tumor clearance following radiotherapy estimated by comparing radioresponse between primary esophageal cancer and its lymph node metastasis.

BACKGROUND/AIMS: We estimated the capacity for exfoliative mechanical clearance which could occur in shrinkage of esophageal tumors following radiotherapy; both mechanical clearance and phagocytotic biological clearance of another clearance mechanism could participate in primary diseases located on outer tissue surfaces, whereas only biological clearance can participate in lymph node metastases surrounded by normal tissues which prevent mechanical clearance. METHODOLOGY: Twenty-one patients with primary esophageal cancer and lymph node metastasis both treated by radiotherapy with the same dose were reviewed. The extent of tumor shrinkage was estimated by measuring the size on computed tomography scans before and after radiotherapy. The capacity for biological clearance plus mechanical clearance (primary disease) or biological clearance alone (lymph node metastasis) was defined as the slope of a tumor shrinkage curve. The capacity for mechanical clearance was estimated by intra-patient subtraction. RESULTS: Extent of tumor shrinkage was consistently greater in primary disease than in lymph node metastasis for each patient, showing significant correlation in extent of shrinkage between them. The capacity was smaller for mechanical clearance than for biological clearance as a whole, showing no correlation between them. CONCLUSIONS: Mechanical clearance is highly likely to participate extra in the shrinkage of tumors located on outer tissue surfaces; therefore, these tumors will normally respond more highly than parenchymal tumors.

Aged↗

PubMedDate not supplied

Comparison of the cardiac electrophysiologic effects of amitriptyline and clomipramine in the dog after myocardial infarction.

The effects of the tricyclic antidepressants amitriptyline and clomipramine on intraventricular conduction, effective refractory period and incidence of ventricular arrhythmias induced by programmed stimulation, were studied in the dog heart after myocardial infarction. Amitriptyline, at doses of 1 to 3 mg/kg, significantly slowed ventricular conduction of the infarcted zones in a frequency-dependent and a dose-dependent manner. Amitriptyline, at doses of 2 and 3 mg/kg, slightly slowed conduction in normal zones. The effective refractory period was prolonged by amitriptyline at a dose of 2 mg/kg. Amitriptyline increased the incidence of ventricular arrhythmias induced by programmed stimulation. On the other hand, the depressant effect of clomipramine, at doses of 1 to 3 mg/kg, on the conduction of infarcted zones was lower than that of amitriptyline, whereas the severely depressed conduction in the infarcted zone was obviously slowed by clomipramine. The incidence of ventricular arrhythmias did not significantly increase with clomipramine. From the present results, clomipramine seems to have a lower cardiac toxicity than amitriptyline, although clomipramine produces a slight depression of conduction in infarcted zones.

Amitriptyline↗

PubMedDate not supplied

Evaluation of intraoperative radiotherapy for carcinoma of the pancreas: prognostic factors and survival analyses.

Among 145 patients with carcinoma of the pancreas who had been admitted to three institutions between 1976 and 1985, 117 were entered into a prognostic factor analysis system according to Cox's proportional hazards model. The treatment was classified into four modalities: bypass surgery, single-dose intraoperative radiotherapy (IOR), IOR combined with external irradiation, and resection with or without various radiations. The most important prognostic factors for treatment were identified as location of tumor, TNM stage, and relief of back pain. Adjusting the imbalances among the treatment groups using Cox's model, the superiority of IOR with external irradiation was confirmed for both bypass and single-dose IOR. With this adjustment, the survival rates proved to be more meaningful than the simple Kaplan-Meier estimates.

Adenocarcinoma↗

PubMedDate not supplied

Effects of imipramine and amitriptyline on intraventricular conduction, effective refractory period, incidence of ventricular arrhythmias induced by programmed stimulation, and on electrocardiogram after myocardial infarction in dog.

The effects of imipramine and amitriptyline on intraventricular conduction, effective refractory period, incidence of ventricular arrhythmias induced by programmed stimulation and on electrocardiogram changes were studied after myocardial infarction in the dog. Amitriptyline, at doses of 1-3 mg/kg, significantly slowed the ventricular conduction of the infarcted zones in a dose- and frequency-dependent manner. Amitriptyline, at doses of 2 and 3 mg/kg, slowed the ventricular conduction slightly in the normal zone. The effective refractory period was prolonged by amitriptyline at a dose of 1 mg/kg. Amitriptyline increased the incidence of ventricular arrhythmias induced by programmed stimulation. Amitriptyline, at doses of 1-3 mg/kg, increased heart rate and prolonged the PQ, QRS and QT interval. Imipramine, at a dose of 3 mg/kg, slowed the conduction in infarcted zones to a lesser extent than amitriptyline. Imipramine, at doses of 1 and 2 mg/kg, did not significantly increase the incidence of ventricular arrhythmias. Imipramine, at a dose of 3 mg/kg, prolonged the QRS interval. From the present results it appears that imipramine has a lower cardiac toxicity than amitriptyline.

Amitriptyline↗

PubMedDate not supplied

Use of daily low-dose carboplatin in radiotherapy for non-small cell lung cancer.

The feasibility of using low-dose carboplatin (CBDCA) as a radiopotentiator in radiotherapy(RT) for non-small cell lung cancer(NSCLC) patients with unfavorable factors was studied. Fifteen patients with locally advanced and inoperable NSCLC were treated with RT in combination with daily 20 mg/m2 CBDCA. Twelve patients completed the treatment as planned. Thrombocytopenia and leukocytopenia(WHO Grade > or = 3) were observed in 1 and 2 patients, respectively. A complete and a partial response were obtained in 1(6.7%) and 9(60%) patients, respectively. The median survival time was 11 months. Calvert's formula has been used for carboplatin dosing and creatinine clearance applies in place of glomerular filtration rate in the formula. In this schedule, there was no correlation between pretreatment creatinine clearance and the nadir of platelet count(p = 0.9016). The combined use of daily low-dose CBDCA to RT was feasible for NSCLC patients with unfavorable factors.

Adenocarcinoma↗