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Biomedical subjects

M Nakama

Publications and source records attributed to M Nakama.

At least 19 recordsLinked to original sources
PubMed1996

The effects of xylazine on intrauterine pressure, uterine blood flow, maternal and fetal cardiovascular and pulmonary function in pregnant goats.

To investigate the effects of xylazine on pregnant goats, xylazine induced changes in heart rate (HR), arterial blood pressure (ABP) and arterial blood pH and gases in the mother and fetus, as well as changes in intrauterine pressure (IUP) and uterine blood flow (UBF), were studied using a chronic preparation model of pregnant goats. Intramuscular administration of xylazine (0.2 mg/kg b.w.) caused a marked decrease in HR and ABP of the mother, which remained significantly reduced up to 120 min. In the fetus, a significant decrease in HR and a significant increase in ABP were recorded after only 5 min. Significant decreases of maternal arterial blood pH and oxygen partial pressure (Po2) were observed up to 120 and 30 min after the injection, respectively. Fetal arterial blood pH and Po2 also decreased, but these changes were milder and less persistent than those of the mother. Within 2 to 5 min after the administration of xylazine, IUP began to increase and remained high for about 15 min. Thereafter, there was a frequent periodic increase in IUP. After 5 min, UBF decreased significantly and remained low up to 120 min. A fall in UBF was associated with a rise in IUP. These findings suggested that administration of xylazine to pregnant goats results in a decrease in UBF arising from the induction of uterine contractions, a decrease in circulating blood volume, hypoxemia and acidosis in the mother.

Animals↗
PubMed1995

A gene therapy strategy using a transcription factor decoy of the E2F binding site inhibits smooth muscle proliferation in vivo.

The application of DNA technology to regulate the transcription of disease-related genes in vivo has important therapeutic potentials. The transcription factor E2F plays a pivotal role in the coordinated transactivation of cell cycle-regulatory genes such as c-myc, cdc2, and the gene encoding proliferating-cell nuclear antigen (PCNA) that are involved in lesion formation after vascular injury. We hypothesized that double-stranded DNA with high affinity for E2F may be introduced in vivo as a decoy to bind E2F and block the activation of genes mediating cell cycle progression and intimal hyperplasia after vascular injury. Gel mobility-shift assays showed complete competition for E2F binding protein by the E2F decoy. Transfection with E2F decoy inhibited expression of c-myc, cdc2, and the PCNA gene as well as vascular smooth muscle cell proliferation both in vitro and in the in vivo model of rat carotid injury. Furthermore, 2 weeks after in vivo transfection, neointimal formation was significantly prevented by the E2F decoy, and this inhibition continued up to 8 weeks after a single transfection in a dose-dependent manner. Transfer of an E2F decoy can therefore modulate gene expression and inhibit smooth muscle proliferation and vascular lesion formation in vivo.

Animals↗
PubMed1992

[The role of urodynamic study in female patients with urinary incontinence].

To determine the type of urinary incontinence in 96 female incontinent patients, we performed a comparative study between the clinical evaluation and the results of urodynamic studies. Their complaints, physical examination, laboratory examinations including routine urological X-ray and ultrasonic studies, revealed that 15 to 30% of the patients had another type of incontinence than those with stress incontinence, urge incontinence and those in whom diagnosis was made from urodynamic studies. Urodynamic studies disclosed that another urinary incontinence type was observed in 7 to 18% of the patients, who were not improved in spite of treatment which was required because of their complaints and physical examination. Our findings showed that urinary incontinence could not be classified according to the frequency of urination or vesical volume. Urodynamic studies may be essential in female patients with urinary incontinence scheduled to have an operation or for whom initial treatment was unsuccessful.

Adult↗
PubMed1990

[Radiotherapy of carcinoma of the biliary system].

One hundred and twenty-two patients with carcinoma of the biliary system were treated with radiotherapy at Jichi Medical School Hospital from 1977 to 1988. Of these, 100 patients were retrospectively analyzed to obtain the outcome of radiation treatment, while 22 patients were excluded from the analysis for recurrence or previous operation when referred. Most of the patients received a total dose of 40 to 60 Gy, with a fraction dose of 1.8 to 3.0 Gy at 3 to 5 settings per week, and 1.3 to 1.5 Gy with interval of 4 to 6 hrs. in the case of accelerated hyperfractionation. It was observed that the over-all median survival time was 5.0 months and that crude survival rates were 24.1% at 1 year and 16.7% at 2 years. From the investigation of prognostic factors by log-rank test, local response after radiation treatment was found to be a factor which influenced the survival rate with a fair statistical significance. As compared to the survival rate of the patients with no response group (NC plus PD), that of good response group (CR plus PR) was significantly higher (p less than 0.005). Of 6 surviving more than 2 years, 5 patients had good responses including 3 complete responses. The survival rate seems to be higher in a group of the short interval between the first symptom and the start of radiotherapy, of no body weight loss, of a short stenosis and of incomplete obstruction, but is not statistically significant. The results suggest that combined modality or altered fractionation regimes should be tried for carcinoma of the biliary system.

Adult↗
PubMed1989

[Clinical experience of hyperthermia in malignant tumors].

Results in 44 cases of malignant tumors treated by localized radiofrequency hyperthermia are presented. All patients had either one or more failed attempts at conventional therapy or had such advanced disease at presentation that control with conventional modalities was considered unlikely. Hyperthermia were used together with radiation in 42 patients with chemotherapy in 1 patient, and alone in 1 patient. The overall response (CR plus PR) was 50% including a 18% complete response. Tumor response was somewhat better for superficial tumors. We retrospectively have analyzed the association between tumor response and histology, tumor size, temperature, radiation dose and total number of heat sessions. Clinical factors influencing the tumor response were initial tumor size and intratumor temperature. The incidence of overall response increased with a decrease in initial tumor size and an increase of intratumor temperature.

Combined Modality Therapy↗
PubMed1988

[Radiotherapy of metastatic brain tumors].

In order to evaluate the role of radiotherapy cases of brain metastases, we retrospectively have analyzed the results of treatment in 89 patients with brain metastases, who had completed a course radiotherapy at the Jichi Medical School Hospital from August, 1973 to October, 1986. Cases analyzed included 60 patients with lung cancers, 6 with breast cancers, 6 with gastric cancers, 10 with other types, and 7 with unknown primary sites. The over-all median survival time was 4.7 months. Crude survival rates were 38.2% at 6 months, and 11.2% at one year, respectively. Two patients survived more than 3 years. The over-all rate of improvement of neurologic function (NF) were 75.3% of NF III patients, and 58% of NF II patients. There was, however, no significant difference in survival rates between the patients with and without NF improvement. Prognostic factors were investigated by a statistical method of a proportional hazard model. Age, the combined treatment with surgery and irradiation, and the neurologic standard dose (Neuret) were found to be factors which influenced the survival rate with a fair statistical significance. Survival rate increased with a decrease in age, an increase in the thoroughness of the surgical excision, and an increase in the Neuret dose. These data suggest that an aggressive approach to brain metastases in younger patients, so far as clinical judgements permit, may indeed improve survival.

Brain↗
PubMed1988

[Clinical research of radiotherapy in brain metastasis].

One hundred and four patients with brain metastasis were received the conventional radiotherapy from 1980 to 1985 at 3 hospitals. Results were as follows. 1. Primary sites were lung (41 cases), breast (34) and others (29). 2. Tumor was 3.15 cm in mean size (0.6-8.2 cm) and 2.6 in number of average (1-15) 3. Radiation dose was 46.5 Gy in average (30-66 Gy) and almost of all cases were irradiated with whole brain field. 4. Over all response rate on CT findings was 65.4% (CR rate: 23.1%) and 63.4% for lung and 73.5% for breast cancer. 5. Survival rate were 25.5% in 1 year, 8.8% in 2 year, 5.4% in 3 year and 3.6% in 5 year. 6. The longer interval was between onset of brain metastasis and primary treatment, the longer survival after brain irradiation. 7. No significant differences of survival rate were seen in size and in number of brain metastasis and with on without improvement of neurological symptoms. 8. The better response was on CT, the better prognosis after radiotherapy. 9. Identification of treatment for brain metastasis according to patient's characteristics and tumor factors were important.

Adult↗
PubMed1988

[Radiotherapy of squamous cell lung cancer].

A retrospective study was made of 56 patients with squamous cell lung cancer, who were inoperable or unresectable and had completed a course of radiotherapy at Jichi Medical School Hospital from August, 1973 to December, 1986. All cases had a performance status score of 80-100 (Karnofsky), no evidence of a distant metastases and tumors that had received a minimum total dose of 50 Gy. The patients were treated with one of three therapy regimens: split course (SC, 32 Patients), conventional fractionation (CF, 13), or multiple daily fractionation (MDF, 11). The over-all median survival time was 13.0 months, and the 2 and 5-year survival rates were 29.2% and 14.7%, respectively. The patients treated with the split course had the lowest survival rate in comparison with the other two groups. Comparison of the patients with the continuous course (CF + MDF) were significantly higher (P less than 0.025) than that of the split course. Patients with MDF had better local control. Age, tumor stage, and the size of the booster field were found to be factors which influenced the survival rate with a fair statistical significance. The survival rate increased with an increase in age, a decrease in the tumor stage, and in the size of the booster field. These findings have important implications for the design of future clinical trials for patients with squamous cell lung cancer.

Aged↗
PubMed1985

Treatment of bladder carcinoma in patients more than 80 years old.

We reviewed 26 patients more than 80 years old with bladder carcinoma to determine if an active surgical policy is justified. Ten patients with superficial carcinoma were treated with transurethral resection; none died of cancer and half have survived 5 years. Of 16 patients with invasive carcinoma 9 underwent total cystectomy with urinary diversion and 2 underwent partial cystectomy. There was no operative mortality. Postoperative complications were not serious. Five of the 9 patients who underwent total cystectomy are alive, with a mean survival of 35 months. The 4-year crude survival rate was 50 per cent. Both patients who underwent partial cystectomy died within 2 years. One patient treated with radiotherapy alone and 1 without any treatment have survived 2 years. These results suggest that contrary to the general tendency towards conservative treatment, a curative operation is worth attempting in elderly patients with bladder carcinoma.

Adenocarcinoma↗
PubMed1980

Radionuclide angiography of vascular lesions of the spinal cord. Its efficacy in selecting patients for spinal angiography.

Selective angiography of the spinal cord is essential for both definitive diagnosis and preoperative evaluation of vascular lesions of the spinal cord. However, the complexity of angiography precludes its use in evaluating every spinal cord lesion. Radionuclide angiography successfully demonstrated vascular lesions of the spinal cord in our two cases, one a hemangioblastoma and the other an arteriovenous malformation. Myelography had not been conclusive in either case. The value of radionuclide angiography as a screening test for vascular lesions of the cord is stressed.

Adolescent↗