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Biomedical subjects

N Masaki

Publications and source records attributed to N Masaki.

At least 55 records · Page 3Linked to original sources
PubMed1992

In situ detection of oxidative stress in rat hepatocytes.

In rat hepatocytes in primary culture incubated with nitro blue tetrazolium, formazan content was increased by addition of t-butyl hydroperoxide, a potent oxidant, in a dose-related manner, but not by addition of valinomycin, which kills hepatocytes through mitochondrial damage. This increment after t-butyl hydroperoxide addition was not seen in hepatocytes preincubated with deferoxamine mesylate, a ferric iron chelator which inhibits radical formation. Liver perfusion with nitro blue tetrazolium and t-butyl hydroperoxide in rats produced formazan deposition faintly on the surface of hepatocytes throughout the liver and prominently in the cytoplasm of some hepatocytes, which was attenuated when performed following deferoxamine mesylate perfusion. When liver perfusion with nitro blue tetrazolium was performed in carbon tetrachloride-intoxicated rats, formazan deposition appeared diffusely in hepatocytes in the centrilobular areas. Similar deposition was also observed on the surface and in the cytoplasm of hepatocytes in the periportal and mid-zonal areas in rats undergoing post-ischaemic reperfusion. Liver perfusion with nitro blue tetrazolium can detect in situ oxidative stress in hepatocytes and may be a useful tool for studying the role of lipid peroxidation in rat liver injury.

Animals↗
PubMed1992

Hepatocyte membrane stabilization by prostaglandins E1 and E2: favorable effects on rat liver injury.

When prostaglandin (PG) E1 was continuously administered to rats from 24 hours before giving a dose of carbon tetrachloride, deranged serum glutamic pyruvic transaminase levels and prothrombin time were significantly reduced 12 hours after intoxication compared with controls. A similar effect of PGE1 was seen at 24 hours in D-galactosamine-intoxicated rats. Liver histology showed a comparable attenuation of injury in these rats. These results were consistent with reported effects of PGE2, suggesting that both prostaglandins may share a common pathway in protection against liver injury. When PGE1 or 16,16'-dimethyl PGE2 was added to the medium of primary cultured rat hepatocytes, lipid peroxidation-dependent killing of the cells by tert-butyl hydroperoxide was significantly attenuated without affecting the extent of malondialdehyde accumulation compared with controls. Both prostaglandins significantly reduced the extent of increased plasma membrane microviscosity of these cells assessed by 1-[4-(trimethyl-ammonio)phenyl]-6-phenyl-1,3,5-hexatriene. PGE1 and PGE2 may possess cytoprotective effects on liver parenchymal cells through stabilization of membrane microviscosity, which may contribute to protection against liver injury.

16,16-Dimethylprostaglandin E2↗
PubMed1992

Molecular-resolution images of aspirin crystals with atomic force microscopy.

The atomic force microscope was developed in order to image arrays of molecules on the (001), (100) and (011) faces of aspirin crystals in water. Lattice spacings and symmetries of methyl groups and the part of the phenyl groups on the (001) face in water are consistent with X-ray diffraction data. Surfaces of the (100) face that show the best-developed cleavage, in general, are difficult to image. Although the lattice constant derived from (100) image is consistent with the X-ray diffraction data, the c-glide plane symmetry is lost and diffused spots are observed that are 1.8-3.1 times more elongated than (001) spots. It is not possible to image the (011) surface. This initial success in imaging the molecular crystal surfaces of drug compounds has clarified the different submolecular structures of the three different crystal faces, and the close relationship between the imaging difficulties and the differences in the dissolution process in water.

Aspirin↗
PubMed1992

Preliminary results of concurrent cisplatin and radiation therapy in locally advanced bladder cancer.

Between March 1981 and March 1990, 15 patients with locally advanced transitional cell carcinoma of the bladder were treated concurrently with cisplatin and radiotherapy. Treatment comprised a radiation dose of 40-50 Gy in 20-25 fractions over 4-5 weeks and intravenous infusion of cisplatin with hydration during days 1-5 and 22-26. The total scheduled dose of cisplatin was 200 mg. A complete response (CR) was seen in 3 patients (2 T2 tumours and 1 T3) and the other 12 were regarded as partial responders. Two of the 12 partial responders (1 T2 tumour and 1 T4) underwent cystectomy after treatment, but 9 patients (2 T2, 6 T3 and 1 T4) underwent only transurethral resection. The remaining patient (with a T4 tumour) died from systemic disease, further treatment not being possible because of unrelated heart failure. In 3 CR patients and 9 with a partial response (PR), bladder function was preserved and they have survived for a mean of 18.3 months (range 5-47) after therapy. Although 4 patients in this group had recurrent bladder tumours and 1 died from cancer in another part of the body, 7 have survived with normal bladder function and no recurrence. It is concluded that concurrent cisplatin and radiation therapy is a safe and viable regimen and may be considered as a means of preserving the bladder in patients with locally advanced transitional cell carcinoma.

Aged↗
PubMed1992

[Indication and problems of radiation therapy of elderly patients with cancer].

The incidence of cancer and the patients treated with radiation therapy increased with age. Of 5778 patients treated with radiation therapy at the Center for Adult Diseases, Osaka, 37.5% are over 65, and 10.8% are over 75 years old. Older patients with cancer have a lower survival rate. Patients over the age of 75 with carcinoma of the pharynx, esophagus, lung, and uterine cervix have decreased survival compared with younger patients. However, for the patients with carcinoma of the larynx, age is not a determinant of prognosis. With respect to radiation therapy, it is not clear whether elderly patients differ from younger ones in responsiveness. However, a decreased tolerance for radiation therapy might be expected and under-dosing with radiation therapy may be more prevalent. More study of the optimal management of elderly patients with cancer is needed.

Aged↗
PubMed1992

Radiation therapy for the supraclavicular lymph node metastasis after curative resection of the esophageal carcinoma.

172 patients underwent curative resection for squamous cell carcinoma of the esophagus. The five-year actuarial survival rate was 38%. 21 of 27 patients who developed nodal metastasis of the supraclavicular lymph node were irradiated with a total dose of 40 to 70 Gy over four to seven weeks. This retrospective study showed the following results: 1. Complete response by radiation therapy was obtained 4/4 in tumor size within 2 cm, 7/10 in 2.1 to 5.0 cm with a total dose of 60 to 70 Gy, while 1/5 with a total dose of 40 to 56 Gy. 2. There were statistically significant differences of survival curves between multiple metastases and single metastasis of the supraclavicular lymph node (p less than 0.01).

Aged↗
PubMed1992

Radiation therapy for the esophageal carcinoma: external irradiation versus high-dose rate intraluminal irradiation.

From September 1977 through December 1989, 149 patients with esophageal carcinoma were treated with external irradiation (EI) with or without high-dose rate intraluminal irradiation (HDRII) using remote afterloading system. Two-year relapse-free survival rates were 52% in sage I (n = 23), 24% in stage II (n = 61) and 19% in stage III (n = 65). Two-year survival rates were 66% in complete response (CR) group (n = 65) and 7 to 9% in non-CR group (n = 84). Concerning CR group external irradiation alone (mean +/- S. D.: 66.5 +/- 5.2 Gy) showed higher local control rate than EI (60.0 +/- 0.4 Gy) + HDRII (10 Gy) (30/38 versus 15/27, p = 0.044), especially in ulcerative type (17/19 versus 5/11, p = 0.009). This preliminary result suggests that HDRII is not effective for the local control of the ulcerative lesion as a boost therapy.

Adult↗
PubMed1991

[MR imaging of osteoradionecrosis of the mandibula following radiotherapy for head and neck cancers].

Magnetic resonance (MR) images of 13 patients with osteoradionecrosis of the mandibula were analyzed. Abnormalities were noted in all patients and could be classified into three groups. In nine patients, MR signals were homogeneously low in intensity on both T1 weighted images (T1WI) and T2 weighted images (T2WI), suggesting fibrosis of bone marrow. These nine patients had suffered radiologically and/or clinically overt osteoradionecrosis more than ten months previously, and inflammatory symptoms had settled down by the time of MR study. Two patients showed low signal intensity on T1WI and an area of inhomogeneous high intensity in a diffuse area of low signal intensity on T2WI, suggesting acute inflammation in the irradiated fibrous bone marrow. Both patients suffered pathologic fracture due to osteoradionecrosis and showed severe inflammatory symptoms at the time MR study. In one of the two patients, these pathologic changes were confirmed in surgically excised mandibulectomy specimens. The other two patients showed homogeneous low signal intensity on T1WI and high signal intensity on T2WI, a finding that may be due to slight inflammation. However, in one of the two patients, this signal feature possibly indicated loose fibrosis with marked cellularity.

Adult↗
PubMed1991

Insulin and glucagon therapy of acute hepatic failure.

When insulin and glucagon are administered to rats with severe liver injury, survival is enhanced with an attenuation of the liver injury compared to that of untreated controls. In rats with acute liver injury both hormones produce a rapid normalization of hepatic protein content following initiation of DNA synthesis. When rats receive both hormones after partial hepatectomy, the first burst of DNA synthesis reaches a maximum earlier than that seen in controls. Both hormones enhance the increment of hepatic putrescine essential for DNA synthesis through activation of ornithine decaroxylase and/or spermidine-N1-acetyltransferase. The enhancement of putrescine content by each hormone is additive. Putrescine supplementation promotes hepatic DNA synthesis after hepatectomy. Based on these data, we conclude that a combination of insulin and glucagon is effective in the therapy of acute hepatic failure in rats. The restoration of liver function as well as the stimulation of liver cell proliferation via putrescine production may contribute to this effect.

Acetyltransferases↗
PubMed1991

Atomic force microscope images of the surfaces of aspirin crystals at submolecular resolution.

The atomic force microscope has been developed and used to image arrays of molecules at the (001) and (100) faces of aspirin crystals in water and in air. Lattice spacings composed of methyl groups and the part of the phenyl groups on the surface of the (001) in water, are consistent with X-ray diffraction data. The surface of (100) face which shows most perfect cleavage in bulk, is more difficult to image. This initial success in imaging at drug crystal surfaces clarified the different structural behavior at the submolecular level for three crystal faces, and the close relationship to the differences in the dissolution velocity.

Aspirin↗
PubMed1991

Usefulness of pulsed Doppler ultrasound in detection of angiographically evident recurrence of hepatocellular carcinoma after arterial embolization treatment.

Because hepatocellular carcinoma treated by transcatheter arterial embolization often regains its size, routine follow-up is necessary. The usefulness of pulsed Doppler ultrasound for detection of this type of recurrence was compared with ultrasonography and computed tomography in 21 such hepatocellular carcinomas. Of 15 hepatocellular carcinomas diagnosed by angiography as showing recurrence, four were detected with ultrasonography and five were detected with computed tomography. Doppler signals were obtained in the peripheral portions corresponding to tumor vessels or stains on angiograms in 14 of these 15 hepatocellular carcinomas, but they were undetectable in six hepatocellular carcinomas with no recurrence. All signals disappeared after transcatheter arterial embolization. One false-negative hepatocellular carcinoma with pulsed Doppler ultrasound showed faint tumor stains on angiograms; these were also negative on ultrasonography and computed tomography. Pulsed Doppler ultrasound may be superior to ultrasonography and computed tomography as a routine procedure to detect the recurrence of hepatocellular carcinoma treated by transcatheter arterial embolization.

Aged↗
PubMed1991

Sonographic staging of cancer of the mobile tongue.

In order to determine the value of sonography (US), in staging cancer of the mobile tongue, 57 patients were studied prospectively. Real-time sector scanners (5 and 7.5 MHz) were used with a submental approach. The findings by US were compared with those obtained by inspection and palpation and in 13 operated patients with the surgical results. US failed to visualize the tumor in 3 of the 57 patients (5%); in 30 patients (53%), the tumor was considered to be of nearly the same size by US and by palpation, but in 17 cases (30%), to be larger by US than by palpation, and in the remaining 7 cases (12%), to be smaller by US. Extension across the midline (8/8), and depth of tumor penetration, or extension to adjacent structures (5/5) were more correctly evaluated by US. We conclude that US is useful for staging work-up of tumors of the mobile tongue.

Adult↗
PubMed1990

[Treatment results of maxillary sinus carcinoma. A retrospective study].

The treatment results of a total of 617 cases with maxillary sinus carcinoma mainly treated by radiotherapy at the Department of Radiology, Osaka University Hospital between 1967 and 1983 were reviewed. The overall actuarial 5-year survival rate was 36.2%. The cases were divided into 3 groups by period of the treatment modalities corresponding each 5-year survival rate of 24.1% on 217 patients for 1967 to 1971, 40.0% on 155 patients for 1972 to 1975, and 44.6% on 245 patients for 1976 to 1983. The treatment results have improved in 5-year survival rate as modifying treatment modality. The actuarial 5-year local control rate was 60.0% for T1 on 9 patients, 43.1% for T2 on 181 patients, 31.7% for T3 on 246 patients, and 19.2% for T4 on 181 patients, respectively. For more detailed analysis of the results, the cases were divided into 4 groups according to the initial treatment; the group 1 was treated by radiotherapy alone (RT), the group 2 by radiotherapy combined with intra-arterial infusion of 5-fluorouracil (RT + 5-FU), the group 3 by radiotherapy combined with surgical removal of the tumor mass through curettage under the general anesthesia (RT + OP) and the group 4 by multidisciplinary procedure combined with radiotherapy, 5-FU regional infusion and curettage (RT + 5-FU + OP). In the T2 cases, the 5-year actuarial local control rate was 25.5% for RT on 51 patients, 45.0% for RT + 5-FU on 55 patients, 58.2% for RT + OP on 23 patients and 51.5% for RT + 5-FU + OP on 52 patients, respectively. In the T3 cases, the rate was 13.2% for RT on 85 patients, 33.6% for RT + 5-FU on 78 patients, 52.3% for RT + OP on 31 patients and 45.9% for RT + 5-FU + OP on 52 patients, respectively. In the T4 cases, the rate was 7.6% for RT on 77 patients, 27.2% for RT + 5-FU on 52 patients, 17.8% for RT + OP on 20 patients and 31.5% for RT + 5-FU + OP on 32 patients, respectively. The combination therapy with 5-FU regional infusion and/or curettage had successfully improved the local control rate. On the T2 and T3 cases of RT + OP, an additive effect of 5-FU infusion was not significant, and also on the T4 cases of RT + 5-FU, any usefulness of curettage could not be found.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Nodular histiocytic lymphoma, emphasizing results of stage I disease treated by radiotherapy. A report of the Japan Lymphoma Radiation Therapy Study Group (JLRTG).

The records of 49 patients with nodular histiocytic lymphomas (NH) who were treated from 1972 to 1985 in hospitals belonging to the JLRTG were retrospectively reviewed. The actuarial survival rate and relapse-free survival rate of all patients after 5 years were 55.0 and 51.3%, respectively. Twenty-one patients with stage I disease had a significantly better survival rate than did 12 patients with stage II disease (P less than 0.01). Without combination chemotherapy, all 15 patients with stage I NH treated by radiation therapy were in complete remission, and 14 of them remained alive and well. Among these 15 patients, no difference in relapse was observed between patients who received involved field irradiation (1 of 6) and those who received extended field irradiation (2 of 9). Patients with stage II or more NH should be treated with intensive chemotherapy and radiotherapy, as are patients with diffuse histiocytic lymphoma (DH). However, involved field radiotherapy with careful follow-up observation may be the treatment of choice for patients with stage I NH, provided their tumors are not bulky.

Adult↗
PubMed1990

[Tolerance dose of the small intestines and colon in patients with carcinoma of the uterine cervix].

From the clinical data of the 199 patients with carcinoma of the uterine cervix from August 1978 to December 1982 using external irradiation and RALS, the tolerance dose of rectum and sigmoid colon were considered as 65 Gy and 70 Gy, respectively. On the other hand, from the review of 86 patients who had been treated for paraaortic lymph node based on a survey of Kansai Cancer Therapist Group, the tolerance doses of small intestine were considered as 40-50 Gy. For further reassessment of tolerance dose, the analysis of volume factor and basic research for pathogenesis of complication are essential.

Aged↗
PubMed1989

Protease inhibitors do not prevent the killing of cultured hepatocytes by cystamine.

A study was made of the conditions of the killing of cultured hepatocytes by the reactive disulfide cystamine. Six to 12 mM cystamine killed up to 60% of the hepatocytes within 3 hours. The cytosolic calcium ion concentration rose prior to the loss of viability. Treatment with EGTA in a Ca2+-free medium lowered the initial Ca2+ concentration and prevented the rise in response to cystamine. However, there was no change in the number of dead cells. Furthermore, the sensitivity of cultured hepatocytes to cystamine was unaffected by the concentration of calcium in the culture medium. Addition to the culture medium of 3 protease inhibitors, leupeptin, antipain, or chymostatin, did not reduce the extent of cell killing by cystamine despite an inhibition of protein degradation. These data do not support the hypothesis that the toxicity of cystamine is necessarily mediated by proteases activated by a rise in the cytosolic calcium ion concentration.

Animals↗
PubMed1989

[The results of radiation therapy of patients with pure seminoma of the testis].

Between 1967 and 1985, 75 patients with pure seminoma of the testis were treated with radiation therapy for periaortic and ipsilateral iliac areas following orchiectomy at the Department of Radiology, Osaka University Hospital. All patients except three were followed at least 2 years. Concerning patients who received 28-30 Gy, all of 48 patients with N0 disease were controlled and alive 2 to 20 years after radiation therapy. All of four patients with N1 disease were controlled and alive 6 to 16 years after radiation therapy. Six of 7 patients with N2 disease were controlled and alive 6 to 19 years after radiation therapy but one patient with T1N2 disease who received 30 Gy to periaortic and ipsilateral iliac areas had recurrence in a paraaortic lymph node 11 months after radiation therapy. As for patients with N3 disease two patients were controlled after 38 Gy and 48 Gy, respectively. No complication was observed after radiation therapy. No sterility seemed to be induced by irradiation to periaortic and ipsilateral iliac areas. It may be concluded that dose of 30 Gy to periaortic and ipsilateral iliac areas is recommended for patients with N0 disease. However, for patients with N1 or N2 disease higher dose of 35 Gy or more is recommended.

Adult↗