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Biomedical subjects

K Kamiya

Publications and source records attributed to K Kamiya.

At least 307 records · Page 17Linked to original sources
PubMed1985

Cushing's disease: pituitary microadenoma demonstrated by high resolution computed tomography with thin slices.

A girl 16 7/12 years of age with Cushing's disease secondary to pituitary microadenoma is described. The tumor was very clearly demonstrated by high-resolution contrast-enhanced computed tomography (CT) with thin slices and was removed by transsphenoidal microadenomectomy. In some patients with Cushing's disease levels of ACTH and cortisol are not always high. Therefore, high-resolution contrast-enhanced CT with thin slices should be performed when the diagnosis of Cushing's disease is suspected even when the definite diagnosis cannot be established by endocrinological examinations.

Adenoma↗
PubMed1985

Cerebral blood flow during open-chest cardiac massage with occlusion of the descending aorta in dogs.

Cerebral blood flow (CBF) and carotid blood flow (CAF) during open-chest cardiac massage with and without occlusion of the descending aorta was examined in 10 dogs to assess whether they were augmented by occlusion. In control measurements with a normally beating heart, CBF with and without occlusion of the descending aorta were 17.8 +/- 2.3 and 13.8 +/- 2.2 ml/min (+/- S.E.M.), which were not significantly different. Cerebral blood flow during open-chest cardiac massage were 6.1 +/- 1.0 with occlusion and 5.7 +/- 1.0 ml/min without occlusion of the descending aorta, which were also not significantly different. By contrast, CAF increased significantly with occlusion of the descending aorta both during control measurement, with mean increases of 61.1% and 92.2% during open-chest cardiac massage (P = 0.05). While occlusion generally failed to augment CBF; in two dogs resuscitation was successful by manual cardiac massage. With the restoration of cardiac activity it increased immediately to twice that of control blood flow, and then gradually returned to the control level. Based on these observations, it is the author's opinion that every effort should be directed toward the restoration of cardiac activity as quickly as possible during circulatory arrest, and to increase CBF which is essential for neurological recovery.

Animals↗
PubMed1985

Histological observations on rat popliteal lymph nodes after blockage of their afferent lymphatics.

Afferent lymphatic vessels to the popliteal lymph node in the rat were blocked, and the node was histologically examined 2-35 weeks later. After the operation, the node was reduced in size and its lymphoid structures, such as germinal centers, lymph follicles and deep cortex units, were decreased in size and number. At 16 weeks, the lymphoid organization of the node reached a minimal level, but the node still exhibited reduced numbers of lymphoid structures. The lymphoid parenchyma of the node, although reduced in size, showed no noticeable change in cellular density during the period of observation. The changes observed in the popliteal node following blockage of the afferent lymphatics were interpreted as resulting from a reduced supply via the afferent lymph of antigens and other factors on which the development and persistence of the lymph node structures are believed to depend.

Animals↗
PubMed1985

Generation of lymphomagenic mouse type-C viruses from radiation- or chemically-induced non-producer T-cell lymphoma cell lines infected with non-oncogenic ecotropic virus.

Highly lymphomagenic mouse type-C viruses were generated from radiation- or chemically-induced T-cell lymphoma cell lines of NFS/N mouse origin infected with a non-oncogenic ecotropic virus E4. By analysis of these progeny viruses, the following results were obtained. 1) The viruses were lymphomagenic in neonatally inoculated NFS/N and C3H/He mice and W/Fu rats but not in Balb/c and C57BL/6N mice, indicating that they possess the Fv-1n tropism of exogenously infected parent virus. 2) Lymphomagenic viruses consisted of plural viral subpopulations. Recombinant mink cell focus-inducing (MCF) and ecotropic viruses were cloned from them. Inoculation of either MCF or ecotropic virus alone or both viruses together did not cause lymphoma in NFS/N mice and there was no evidence of viral replication in the recipients. 3) Inoculation of either MCF- or ecotropic virus-infected NFS-ME cells alone did not cause lymphoma development in pre-irradiated NFS/N mice, while transplantation of both MCF- and ecotropic virus-infected NFS-ME cells resulted in the development of lymphomas of host origin. These results show that lymphomagenic MCF virus was generated through the recombination of E4 viral genome and a modified proviral DNA of endogenous viruses present in radiation- or chemically-induced lymphomas, and that an interaction or synergism of MCF and ecotropic viruses is required for MCF virus to exert lymphomagenic activity.

Animals↗
PubMed1985

Synergistic effect of radiation and N-nitrosoethylurea in the induction of lymphoma in mice: cellular kinetics and carcinogenesis.

The effect of a combined treatment with radiation and N-nitrosoethylurea (NEU), or a split administration of NEU in inducing lymphoma was studied in female C57BL/6N mice. A single intragastric administration of 5 mg of NEU was only slightly lymphomagenic, inducing thymic lymphomas in 20% of mice, while the incidence was elevated to 92% if the NEU treatment was preceded (by 5 days) by 400 rad of total-body X-irradiation, which alone is seldom lymphomagenic. A high yield of lymphoma (84-93%) was also obtained if 5 mg of NEU was delivered in two split doses of 4 mg and 1 mg with a 4 day interval. Drastic injury to both the thymus and bone marrow caused by either 400 rad total-body X-irradiation or the first dose of NEU (4 mg) was followed by a vigorous regeneration within a few days. The maximum induction rate of lymphoma was obtained when the subsequent dose of NEU (1 mg) was given at the peak of DNA synthesis in the bone marrow and thymus following the first treatment. The data indicate that the principal effect of the irradiation or the first dose of NEU was to provide a susceptible cell population, and that a high yield of lymphoma was brought about through the action of the subsequent dose of NEU on a sufficient number of target cells engaged in heightened DNA synthesis.

Animals↗
PubMed1985

High mammary carcinogenicity of neutron irradiation in rats and its promotion by prolactin.

The present study was undertaken to assess the mammary carcinogenic effect of low doses of fission and thermal neutrons in female W/Fu rats. Only 2 of 62 (3.2%) rats exposed to various doses of fission radiation alone developed mammary tumors (MT) in a 12-month observation period, whereas 21 of 63 (33.3%) similarly irradiated rats developed MT if further treated with prolactin; the lowest effective dose was 4.1 rad, which contained only 1.7 rad of fission spectrum neutrons with an average energy of 2.0 MeV. The long survival of radiation-initiated potentially malignant cells was suggested by the observation that excess numbers of MT developed in irradiated rats in whom prolactin treatment was started as late as 12 months after irradiation. The negligible contribution of gamma-rays, one component of the reactor radiations, to the rat mammary carcinogenesis was proven by a simulation experiment with 60Co gamma-rays. Thermal neutrons with an average energy of 0.025 eV were less effective than fission neutrons. The rat mammary carcinogenic effects of 180 kVp X-rays, 14.1 MeV fast neutrons, 0.025 eV thermal neutrons and 2.0 MeV fission neutrons were estimated in such a way as to compare the dose of each radiation that gave an MT incidence of 40% of that in irradiated, prolactin-treated rats. The efficiency of fission spectrum neutrons is much higher than those of other radiations; the relative biological effectiveness (RBE) of fission spectrum neutrons was 17.8 against X-rays. Based on these findings, the relevance of animal data to tumor induction in atomic bomb survivors is discussed.

Animals↗
PubMed1985

Protective effects of progesterone and tamoxifen in estrogen-induced mammary carcinogenesis in ovariectomized W/Fu rats.

The protective effect of progesterone or tamoxifen, an antiestrogenic agent, was investigated in estrogen-induced mammary carcinogenesis. Multiple mammary tumors (MT) of tubular or medullary carcinoma type developed at a high rate following prolonged treatment of ovariectomized W/Fu rats with diethylstilbestrol or 17 beta-estradiol. All MTs were located adjacent to the nipple and were slow-growing. The induction rate, multiplicity and size of estrogen-induced MTs were reduced by the simultaneous administration of either progesterone or tamoxifen. The estrogen-induced pituitary tumorigenesis was effectively inhibited by tamoxifen treatment, but it was not affected by progesterone. The results indicated that the inhibitory effect of progesterone or tamoxifen in estrogen-induced carcinogenesis is attributable to interference with the binding of estrogen to the estrogen receptors on the target cells.

Adenoma↗
PubMed1984

Reconstruction of lymph follicles in the mouse popliteal lymph node after X-irradiation damage.

In order to suppress possible "de novo" formation of follicles in the node after irradiation, animals to be irradiated received surgical operations to block the afferent lymphatics to the popliteal node on one side, the corresponding node on the other side left intact. 600 R whole body X-irradiation severely destroyed lymph follicles in the nodes of both sides, but the number of follicles in the node on either side recovered toward normal by 3 weeks after irradiation, regardless of whether they contained germinal centers or not. In animals exposed to 1,000 R whole body X-irradiation and infused with bone marrow cells, no lymph follicles were observed in the nodes on day 9. If such treated animals were given 1.0 X 10(8) lymph node cells on day 5, lymph follicles were reconstructed in the nodes of both sides on day 9. In animals irradiated with 1,000 R to the lower half of the body, the number of follicles in the node on either side remained comparable to that of the unirradiated control node. The results favor the interpretation that although X-irradiation destroys the lymphoid elements of the follicles, the stromata of follicles persist and preserve the ability to collect small lymphocytes, and that lymph follicles are reconstructed at the sites of the stromata persisting from damaged follicles.

Animals↗
PubMed1984

Formation of lymph follicles and germinal centers in draining lymph nodes after local injection of phytohemagglutinin and lipopolysaccharide in mice.

Changes in the number of lymph follicles and germinal centers in draining popliteal lymph nodes were investigated in 8-week-old mice injected with either phytohemagglutinin (PHA) or lipopolysaccharide (LPS) into the footpad of the left hind leg. The dose of PHA injected ranged from 10 micrograms to 1 mg, and that of LPS, from 2 to 200 micrograms. In unstimulated animals, the popliteal lymph nodes contained only a small number of germinal centers, and many of the lymph follicles in the nodes were in the form of primary follicles. In the draining lymph nodes, regardless of the dose injected, PHA induced germinal center development in existing primary follicles, but eventually failed to stimulate the formation of new lymph follicles and germinal centers. On the other hand, LPS not only induced germinal centers in the existing follicles, but also stimulated the formation of new primary follicles, many of which then developed germinal centers. The occurrence of new follicles in the LPS-treated lymph nodes was dose-dependent, and LPS appeared to cause de novo formation of follicles.

Animals↗