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Biomedical subjects

N Hamada

Publications and source records attributed to N Hamada.

281 records · Page 16Linked to original sources
PubMedDate not supplied

Simulium (Psaroniocompsa) tergospinosum new species (Diptera: Simuliidae) in siolii group from the southern part of the State of Amazonas, Brazil.

The larva, pupa, male and female of Simulium tergospinosum n. sp. are described and illustrated. The adults of this new species share many characters with species in the subgenus Psaroniocompsa, where it is placed. The larva of this species bears dorsal and lateral triangular tubercles on the abdomen and multiply branched scale-like setae on the body, suggesting that it belongs to the S. siolii species group. S. tergospinosum n.sp. was collected along the Juma River, Apuí county, in the southern part of the State of Amazonas, Brazil. The Juma, a black-water river, is a tributary of the Aripuanã River in the Madeira River hydrographic basin, on the southern part of Amazonas. Females were collected biting humans along the water courses during the sampling period (in the dry season).

Animals↗
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[Clinical characteristics of postinfarction left ventricular aneurysm with extensive calcification].

The authors experienced 4 cases of calcified postinfarction aneurysm of the left ventricle. They were all male, aged 55 to 71 (mean 64). Risk factor for coronary artery disease was only smoking in 2 patients, but there was none in the others. They had had acute anteroseptal or extensive anterior infarction at age 41-57 years (mean 49.3), and associated major cardiac events 10-22 years (mean 14.5) after acute myocardial infarction. Ventricular tachycardia, congestive heart failure and systemic thromboembolism were seen in 4, 2 and 1 patients respectively. However, none developed angina pectoris. In the 2 patients in whom signal-averaged electrocardiogram was performed, late potential was detected, so it was suspected that ventricular tachycardia could be due to reentry. Left ventricular end-diastolic pressure was elevated in all patients except one and ranged from 11 to 22 mmHg. Left ventricle was dilated in all cases and the end-diastolic volume index ranged from 143 to 503 ml/m2. The left ventricular ejection fraction ranged from 11 to 24%. However, in 2 of the 4 patients, the cardiac index was within normal limits, and evidence of congestive heart failure was absent. In 2 other patients with associated congestive heart failure, cardiac indices were 2.32, 1.56 l/min/m2 respectively. Coronary arteriogram showed a total occlusion in the left anterior descending (LAD) artery in all cases, and only the LAD artery was affected in 2 patients. In the remaining 2 patients, the right coronary arteries also were significantly stenotic or totally occluded, i.e., they had 2-vessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Changes of mutant-type p53 expression in squamous cell carcinoma of the head and neck during radiation therapy and its clinical significance: comparison of an immunohistochemical method and PCR-SSCP assay.

P53 has been reported to be one of tumor suppressor genes that play a major role in signal transduction following many kinds of stresses, including ionizing radiation. Changes in p53 expression during radiation therapy in tumor tissues have not yet been reported. We determined whether radiotherapy changes p53 expression in human squamous cell carcinomas of the head and neck, and established the possible correlations between p53 expression and the therapeutic effects of radiation therapy. 30 patients with tumors of the oral cavity, oropharynx, and maxillary sinus were examined, and all the tumors were confirmed as squamous cell carcinomas. Biopsies were performed on the cancer tissues before treatment and at doses of 4, 10, and 20 Gy of radiotherapy, and the specimens were preserved in liquid nitrogen for further examination. Samples were immunohistochemically stained using streptoavidin-biotin peroxidase method and a monoclonal antibody against p53 (Ab-3, mutant type). For all the samples p53 PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) assays were performed. 14 of the 30 patients with squamous cell carcinomas showed expression of p53 in their tumor cells before and/or at 4 Gy or 10 Gy of radiotherapy. Eleven of the 14 tumors showed high radiosensitivity. Results of the p53 PCR-SSCP assays revealed mutations of p53 in 13 of 30 patients examined, and percentages of mutated p53 DNA varied at radiation doses of 4 Gy and 10 Gy. Ten of 12 patients with mutated p53 in their tumors showed decreased percentages of mutated p53 DNA during radiotherapy. The relationship between the immunohistochemical findings and the antitumor effect of a radiation dose of 20 Gy was examined on the correspondent hematoxylin-eosin sections. In patients whose p53 expressions in tumor cells were grades + or ++ or before radiotherapy and/or at 4 Gy of radiotherapy, the tumors responded significantly well to radiation therapy but the patients responded with significantly unfavorable clinical courses. The high radiosensitivity of squamous cell carcinomas in our samples could be explained by an overexpression of mutant type p53 in the tumor cells, and these mutant type p53-positive tumor cells possibly showed radioresponsiveness.

Adult↗
PubMedDate not supplied

Analysis of radiation pneumonitis and radiation-induced lung fibrosis in breast cancer patients after breast conservation treatment.

We examined radiation pneumonitis in breast cancer patients after breast conservation treatment (BCT) and analysed the degree of radiation-induced lung fibrosis by computed tomographies of the chest (chest CT). Fifty-two breast cancer patients were treated with BCT, including breast irradiation and chemotherapy. These patients symptomatic of radiation pneumonitis were examined every two to four weeks. Chest X-rays and chest CT were performed about one year after irradiation. symptoms due to radiation pneumonitis was registered in 9.6% of patients. lungs showed fibrotic changes by chest CT in 90% of the cases. Concurrent or alternative chemotherapy increased the incidence of symptomatic radiation pneumonitis and, to a certain extent, the degree of fibrotic change in the lung after BCT.

Adult↗
PubMedDate not supplied

The immunopotentiation effects of the bifunctional radiosensitizer KIN-806 in comparison with its analogs KIN-804 and KIN-844.

KIN-806 is one of the 2-nitroimidazole derivative hypoxic cell radiosensitizers. Its radiosensitizing effects and the degree of lung metastasis detected were evaluated and compared with its analogs KIN-804 and KIN-844. The immune reactions induced by these radiosensitizers were also analyzed. Female C3H/He mice and SCCVII tumor cells were used. Seventeen days after inoculation of SCCVII tumor cells into the animals, 0.4 g/kg of KIN-806, KIN-804, and KIN-844 was administered to each radiosensitizer group 30 min before 40 Gy was delivered as local irradiation. In each group, KIN-806, KIN-804, and KIN-844 markedly suppressed tumor regrowth in comparison with animals that received irradiation alone. There was no significant difference in the radiosensitizing effects among these three radiosensitizers. A marked suppression of lung metastasis and macrophage/T-lymphocyte infiltration into the tumor were observed only in the KIN-806-administered groups, regardless of the presence or absence of radiation therapy. It therefore appears likely that the lung metastasis suppression was caused by the immune reaction elicited by KIN-806, which is an excellent immunopotentiator as well as an effective radiosensitizer.

Animals↗
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Effect of 3-methylcholanthrene pretreatment on glucuronidation and sulfation in perfused rat liver.

The metabolism of p-nitro[14C]phenol (PNP) was studied in perfused rat liver. Metabolites were identified in perfusate and bile. The perfusion system containing 0.5 mM PNP, at the start, converted the phenol within 2 hr to p-nitrophenyl glucuronide (PNPGA), 31.4% in perfusate and 21% in bile; p-nitrophenyl sulfate (PNPS), 22% in perfusate; and p-nitrophenyl glucoside (PNPG), between 2 and 4% perfusate. Biliary excretion of PNPS and PNPG accounted for less than 2% of PNP. An apparent maximal rate of PNPGA synthesis by the perfused liver, estimated from the rates of appearance of PNPGA in perfusate and bile, corresponded well to the glucuronyl-transferase activities determined in "native" liver homogenates. Sulfation of PNP in the perfused liver exhibited two apparent maximal rates of synthesis, as determined from the rates of appearance of metabolite in the perfusate. A slower rate (R1) occurred when PNP concentration was between 0.13 and 0.5 mM, and a faster rate (R2) when PNP was approximately between 0.025 and 0.13 mM in the perfusate. Possible significance of these findings is discussed. Pretreatment of rats with 3-methylcholanthrene (3MC) increased the apparent maximal rate of PNPGA production by the perfused liver by a factor of 1.7, and biliary excretion of PNPGA by a factor of 1.5. The latter increase was attributed to the increased rate of synthesis of the glucuronide rather than to an increase in the biliary transport maximum, since the 3MC treatment produced no significant effect on the biliary excretion of performed PNPGA added to the perfusate. The 3MC pretreatment increased 1.5-fold the rate of sulfation of PNP, as judged by the increase in R2.

Animals↗
PubMedDate not supplied

Early experiences of breast-conservation treatment combined with tamoxifen and CAF chemotherapy for breast cancer of stages I and II.

A total of 39 patients with breast cancer of stages I and II received breast-conservation treatment (BCT) combined with tamoxifen and systemic chemotherapy (CAF) from August 1989 to March 1993. All of these patients visited the outpatient clinic of the Department of Radiology of Kochi Medical School Hospital, with an obvious desire to undertake BCT. During this period, another two patients with the same desire were treated with modified radical mastectomy, because of obviously positive surgical margins in frozen sections obtained at surgery. The percentage of patients treated by BCT was, therefore, 95.1%. All of the patients were females, and their average age was 49.9 years. Thirty-six of these 39 patients underwent lumpectomy, and another three patients with large-sized tumor or suspected extensive intraductal component underwent quadrantectomy or wide local excision. Nineteen of these 39 patients who were over 70 years old or had no clinically detectable axillary lymph node swelling received tangential field radiotherapy to their ipsilateral axillary region instead of axillary dissection. At the end of May 1993, the mean follow-up time was 22.4 months. Until now, one patient (T2N1M0, stage IIB) has died of distant metastases of breast cancer to bone, liver, lung, and brain, and another patient, aged 81, died of pneumonia with no evidence of breast cancer progression. The overall survival rates were, therefore, 100% (30/30), 90.0% (18/20), and 75.0% (6/8) at 1 year, 2 years, and 3 years, respectively. Cause-specific survival rates were 100% (30/30), 94.7% (18/19), and 85.7% (6/7) at 1, 2, and 3 years, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

CD34-positive cell yield in peripheral blood of cancer patients during radiation therapy.

For the purpose of evaluating the feasibility of inducing CD34-positive cells in peripheral blood by radiation therapy, we examined the changes in CD34-positive cells in 21 cancer patients (16 with lung cancer and five with esophageal cancer) during thoracic radiotherapy using flow cytometry and CD34 monoclonal antibody. Although assays of granulocyte-colony-forming units (G-CFU) and granulocyte-monocyte-colony-forming units (GM-CFU) were also performed for 16 of the patients during radiation therapy, in most of these cases there was approximately one G-CFU or GM-CFU for every 100 CD34-positive cells. Seven of the 21 cancer patients showed percentages of CD34-positive cells of more than 3% (more than mean + 2 S.D.; standard deviation) of mononuclear cells in peripheral blood in at least one of the examinations. However, six of these seven patients were in stage IV with distant metastases (four with lung cancer and two with esophageal cancer), and another lung cancer patient was in stage III. Therefore, CD-34 positive cells were shown to appear in peripheral blood especially in the patients with advanced stages of malignancy, and further examinations are needed to induce CD34-positive cells by radiation therapy for possible application of ultra-high dose chemotherapy supported by peripheral blood stem cell transplantation.

Antigens, CD34↗
PubMedDate not supplied

Influence of the flow rate during flushing on porcine multivisceral preservation.

The effect of flushing flow rate during multiple organ procurement (MOP) on viability of the liver, pancreas, and intestine were investigated in porcine multivisceral transplantation. Splanchnic organs were flushed in situ with 50 ml/kg of 4 degrees C UW solution via the aorta using a pump at a flow rate of 10, 30, or 50 ml/kg/min. After storage and transplantation, we assessed the clearance of hyaluronic acid (CHA) for hepatic endothelial cells function, liver enzymes, amylase, and histology. Two-day survival was 17% in the 10 ml/kg/min group and 67% in other groups. The former group had inadequate flushing out of the hepatic and intestinal grafts, resulting in aggravation of CHA and intestinal tissue injury. At the flow rate of 30 ml/kg/min, the viability and integrity of all organs were well maintained. We conclude that the optimal flushing flow rate would differ for each organ, therefore the common flow rate acceptable for any of the individual grafts should be applied in MOP.

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PubMedDate not supplied

Small bowel rejection in isolated small bowel transplantation and in multivisceral transplantation: a comparative study in a large animal model.

The proposition that a combined graft including the liver protects other organ allografts from the same donor is well known. However, it is not evident in the clinical results. The present experiments were undertaken to compare acute small bowel rejection in isolated small bowel transplantation with multivisceral transplantation. Using 36 outbred, male Large-White pigs, isolated small bowel transplantation (SBTX: n = 9) and abdominal multivisceral transplantation (MVTX: n = 9) were performed without immunosuppression. The survival rate and blood serum samples were monitored postoperatively. In order to compare acute small bowel rejection, sequential biopsy specimens from Thiry-Vella loops were also monitored daily beginning on me 3rd day after transplantation. The specimens were scored from 0 to 3 according to the severity of the rejection. The survival rate was not significantly different. However, significant differences were noted in the cause of the death and in the pathologic changes of the small bowel. In contrast to SBTX, the small bowel rejection of MVTX was significantly delayed and less severe. The rejection score of MVTX was significantly better than SBTX from 5 postoperative days (POD) to 1 lPOD (P < 0.05). The present study demonstrated mat acute small bowel rejection of MVTX graft including the liver was delayed and less severe than that of SBTX in an outbred large animal model.

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