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Biomedical subjects

T Ashikaga

Publications and source records attributed to T Ashikaga.

At least 73 records · Page 4Linked to original sources
PubMed1992

Inhibition of platelet aggregation by prostacyclin is attenuated after exercise in patients with angina pectoris.

We tested whether alteration of platelet sensitivity to prostacyclin (PGI2) is involved in the activation of platelets induced by exercise in patients with stable angina. Twenty patients and 20 control subjects underwent treadmill testing. Blood samples were obtained before and immediately after exercise for plasma thromboxane B2 (TXB2) and 6-keto-PGF1 alpha (6kP) assays and platelet aggregation studies. Dose-response curves for platelet aggregation to collagen were obtained in the presence and absence of 1 nmol/L PGI2 to quantify the antiaggregation effects of PGI2. At rest, platelet aggregation by collagen was enhanced in the patients. However, platelets were more sensitive to exogenous PGI2, apparently associated with lower plasma 6kP levels in the patients. After exercise, plasma TXB2 levels increased in the patients but not in the control subjects. Plasma 6kP levels remained unchanged and platelet sensitivity to PGI2 decreased in the patients whereas these values increased in the control subjects. The exercise-induced changes in platelet sensitivity to PGI2 correlated with those of platelet adenylate cyclase activity in response to 1 nmol/L PGI2 (r = 0.787, p less than 0.01). Thus impaired sensitivity of platelets to PGI2, in addition to the reduced response of prostanoid secretion, might be relevant to the platelet activation associated with exercise in patients with stable angina.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Radiographic abnormalities in Vermont granite workers exposed to low levels of granite dust.

The issue of whether low levels of granite dust exposure lead to radiographic abnormalities after a lifetime of exposure has not been settled. In 1983, we carried out a radiographic survey of the Vermont granite industry, consisting of quarry and stone shed workers who had been exposed to the low dust levels prevailing in the industry since 1938 to 1940. Films were read by three "B" readers, using the ILO classification system, which requires the identification of both rounded and irregular opacities, as well as combinations of both. X-ray films were taken of 972 workers, out of a total work force of approximately 1,400. Of these films, 28 (3 percent) were interpreted by either two or three of the three readers as showing abnormalities consistent with pneumoconiosis. Only seven films (or 0.7 percent of the entire cohort) showed nodular or rounded opacities of the type typically seen in uncomplicated silicosis. The remainder of the abnormal x-ray films showed irregular opacities, largely in the lower lung zones, which are of uncertain significance, but may be related to heavy cigarette smoking and aging, and possibly dust inhalation. In addition, total gravimetric dust concentrations in the workplace were measured; 417 respirable-size mass samples showed concentrations of 601 micrograms/cu m +/- 368 micrograms/cu m. Using previously published estimates of 10 percent quartz in granite dust, the average quartz concentration was 60 micrograms/cu m. Twelve percent of the samples exceeded 100 micrograms/cu m, the current OSHA standard for quartz. We conclude that control of quartz exposure in the Vermont granite industry to levels which are on average less than the current OSHA standard has essentially eliminated definite radiographic changes of silicosis. The significance of the irregular opacities in the lower lung zones seen on a majority of the 28 x-ray films judged to be abnormal is not clear.

Adult↗
PubMed1990

Antiplatelet therapy for atherosclerotic disorders.

Recent studies have revealed the important roles of platelets in atherogenesis via vascular injury. Our in vivo and in vitro studies clearly demonstrate that activated platelets directly inflict injury to vascular endothelial cells, which is associated with a decrease in intracellular cyclic AMP levels in vascular tissues. Antiplatelet therapy is clinically important not only for the prevention of thrombotic episodes but also for the prevention of vascular injury and atherosclerosis. A small dose of aspirin (80 mg) induces clinically hypoaggregativeness of platelets with concomitantly decreased levels of thromboxane A2 in plasma. Our clinical study involving more than 3 years of treatment with small doses of aspirin demonstrated favorable therapeutic effects characterized by hypoaggregation of platelets and increased levels of cAMP and 6-keto PGF1 alpha in plasma which will aid in the prevention of atherosclerosis.

Animals↗
PubMed1989

Utilization of a murine model to optimize volume and dwell time of intraperitoneal cisplatin.

The pharmacokinetics of intraperitoneal (ip) cisplatin were investigated in a murine model. Groups of six animals were studied at initial cisplatin concentrations (Ci) of 50, 100, 200, and 400 micrograms/ml, and at injection volumes (V) of 0.5, 1, 2, and 4 ml. For each Ci and V, four dwell times (Dt) between 1.5 and 120 min were studied. At 180 min mice were killed and five tissues (heart, kidney, liver, bowel, and peritoneum) were obtained for platinum measurement. Platinum recovered from the peritoneal cavity at the end of the dwell time and platinum tissue levels were determined by a radioactive tracer assay using Pt 195m-labeled cisplatin. A total of 384 mice were studied. The permeability times the effective surface area product (pS) was found to be independent of Ci, V, and Dt. Platinum tissue levels were proportional to absorbed dose. As the ratio of platinum tissue level to absorbed dose is constant, it is not possible to change Ci, V, nor Dt to minimize toxicity from a given absorbed dose. This study suggests that the therapeutic index of an individual intraperitoneal cisplatin treatment will not be changed by modifying Ci, V, nor Dt.

Absorption↗
PubMed1989

Cervical change and uterine activity as predictors of preterm delivery.

Premature uterine activity and early cervical change have both been shown to be useful in predicting preterm delivery. Prospective studies evaluating weekly uterine activity and cervical change were performed in 20 women, 17 of whom were at risk for preterm delivery, starting at 20 to 25 weeks' gestation. Patients were followed weekly until either 36 weeks' gestation or until the onset of premature labor or delivery. Seven women delivered before 37 weeks' gestation (preterm group). Thirteen women did not require tocolysis and delivered after 37 weeks' gestation (term group). A Bishop score was assessed weekly and the score added to the prior values in order to obtain a cumulative cervical score. A similar process was used to assess uterine activity. The cumulative values of Bishop score and uterine activity were plotted against gestational age in both groups. There was no observed increase in cumulative uterine activity in the preterm group before delivery. However, there was a progressive increase in cumulative cervical change weeks before delivery in the preterm group (p less than 0.05). Despite the small sample size, we conclude that progressive cervical change precedes the onset of labor and may be a better predictor of preterm delivery than is weekly monitoring of uterine activity.

Cervix Uteri↗
PubMed1989

[A case of extramedullary plasmacytoma of the spleen].

A case of extramedullary plasmacytoma of the spleen in a 39 years-old man was reported. The tumor occupied almost of the spleen and extended to the transverse colon. 67Ga scintigraphy and MRI, particularly T 2-weighted image were useful in diagnosis of the localization.

Adult↗
PubMed1987

The Vermont longitudinal study of persons with severe mental illness, I: Methodology, study sample, and overall status 32 years later.

The authors report the latest findings from a 32-year longitudinal study of 269 back-ward patients from Vermont State Hospital. This intact cohort participated in a comprehensive rehabilitation program and was released to the community in a planned deinstitutionalization effort during the mid-1950s. At their 10-year follow-up mark, 70% of these patients remained out of the hospital but many were socially isolated and many were recidivists. Twenty to 25 years after their index release, 262 of these subjects were blindly assessed with structured and reliable protocols. One-half to two-thirds of them had achieved considerable improvement or recovery, which corroborates recent findings from Europe and elsewhere.

Adult↗
PubMed1987

The Vermont longitudinal study of persons with severe mental illness, II: Long-term outcome of subjects who retrospectively met DSM-III criteria for schizophrenia.

The authors present the findings from a long-term follow-up study of 118 patients from Vermont State Hospital who, when rediagnosed retrospectively, met DSM-III criteria for schizophrenia at their index hospitalization in the mid-1950s. The patients were studied with structured, reliable, multivariate instrument batteries by raters who were blind to information in their records. The rediagnostic process is described, and results of the follow-up are presented. Outcome varied widely, but one-half to two-thirds of the sample had achieved considerable improvement or recovered, in contrast to statements in DSM-III that predict a poor outcome for schizophrenic patients.

Adult↗
PubMed1986

The ear lobe crease sign and coronary artery disease in aortic stenosis.

Ear lobe creases have been proposed as useful indirect markers of coronary artery disease. To test such a hypothesis, this physical sign was evaluated in 100 patients with symptomatic aortic stenosis undergoing cardiac catheterization to establish the hemodynamic severity of the obstruction and the degree of coronary artery involvement. This is a disorder where the coexistence of cardiac ischemia may play an important part in diagnosis and management. Criteria were established for the degree of ear lobe involvement with a grading of mild (Grade 1), moderate (Grade 2), and severe (Grade 3). Significant coronary artery disease was defined as narrowing greater than or equal to 50% and a coronary score was established. Sensitivity, specificity, positive and negative predictive values were calculated, using Bayesian analysis for three levels of assumed coronary artery disease prevalence. An ear lobe crease score was correlated with a coronary artery disease score, taking into account the variables of age, sex, and body mass index. No useful statistical correlations were found and it is concluded that this physical sign is of little practical value in this clinical setting.

Adult↗
PubMed1986

Hexamethylmelamine, methotrexate, 5-fluorouracil as second line chemotherapy after platinum for epithelial ovarian malignancies.

Thirty-three patients were treated with HexAF after previous treatment with cyclophosphamide (C), Adriamycin (A), and cisplatin (P). The patients had either progressed on CAP, had persistent disease after CAP, or recurred after a negative second look. Treatment schedule was hexamethylmelamine (Hex) 150 mg po qd days 1-14, methotrexate (A) 40 mg/m2 IV days 1 and 8, and 5-fluorouracil (F) 600 mg/m2 IV days 1 and 8. Courses were repeated every 4 weeks. Thirty-one of 33 patients were evaluable for response. Three of 31 patients had partial responses, 7 of 31 had stable disease, and 21 of 31 progressed. Median survival of the responders (n = 3) was 23 months and the nonresponders (n = 28) was 6 months (p = 0.027). Patients with less than 1 cm disease (n = 12) had a median survival of 20 months, and those with greater than 1 cm (n = 21) had a median survival of 6 months (p = 0.004). Toxicity was mild. Even with a statistically significant survival advantage for HexAF responders, we consider a response rate of less than 10% unacceptable.

Adult↗
PubMed1984

Treatment of advanced and recurrent ovarian carcinoma with cyclophosphamide, doxorubicin, and cisplatin.

Forty-seven patients with primary advanced (N = 37) or recurrent ovarian carcinoma (N = 10) completed a 12-month course of CAP chemotherapy or developed progressive disease while on therapy and were evaluated. All patients were treated between August 1, 1977 and August 1, 1982. Cyclophosphamide 400 mg/m2, Adriamycin (doxorubicin) 40 mg/m2, and cisplatin 60 mg/m2, were administered every 4 weeks intravenously. After 8 courses the cisplatin was stopped. The patients then received 500 mg/m2 of cyclophosphamide and 50 mg/m2 of Adriamycin. At the cumulative dose of 450 mg/m2, the Adriamycin was stopped and cyclophosphamide was given at 1 g/m2 alone until the patient had received a total of 12-13 courses from the initiation of the chemotherapy protocol. The cardiac, renal, and hematopoetic toxicity of the regimen was mild to moderate. The median survival of the entire study population was 32 months. The median survival of the patients with primary disease was 36 months. The median survival of patients with recurrent disease was 20 months. There was a significant difference in median survival based on size of the largest lesion prior to initiation of chemotherapy. There was no difference in median survival based on tumor grade or comparing Stage III to Stage IV tumors. The most important aspects of the study appeared to be the length of the median survival of the patients, the fact that all patients who were complete responders and who were considered to have no evidence of disease, have been documented by second look, and the success of secondary treatment after second-look procedures revealed persistent tumor. The authors additionally report the use of weight change as an indicator of tumor response, and the importance of the pelvic examination complimented by fine-needle aspiration in following the course of these patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Lack of association between genital mycoplasmas and infertility.

We studied the relation between colonization with Mycoplasma hominis and Ureaplasma urealyticum, and the results of infertility studies in 205 women with involuntary infertility of at least one year's duration. Isolation of M. hominis (but not of U. urealyticum) was significantly (P = 0.002) more common in patients with a history of pelvic inflammatory disease. However, no relation could be shown between these genital mycoplasmas and any of the following: evidence of prior pelvic inflammatory disease as determined by hysterosalpingography and laparoscopy; cervical inflammation; numbers and motility of spermatozoa on postcoital test; pyosemia; quality of cervical mucus; whether the cause of infertility was related to male or female factors, both, or neither; and occurrence and outcome of subsequent pregnancy. Mycoplasmas were cultured from only 10 of 203 endometrial biopsy specimens (4.9 per cent), and in no instance was inflammation associated with this finding. Out studies do not support a role for genital mycoplasmas in the cause of infertility.

Adult↗
PubMed1984

Patterns of adnexal inflammatory damage: Chlamydia, the intrauterine device, and history of pelvic inflammatory disease.

In a study of 204 consecutive infertile couples, 58 women with adnexal abnormalities consistent with prior pelvic infection were identified. The status of those 58 subjects with respect to prior pelvic infection, prior intrauterine device use, and serologic evidence of past chlamydial infection was correlated with the types of adnexal abnormalities identified. Women with serologic evidence of past chlamydial infection were more likely to exhibit severe adhesions and hydrosalpinx formation, and hydrosalpinx formation was related to a history of clinically detected pelvic infection.

Chlamydia Infections↗