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Biomedical subjects

F Hirota

Publications and source records attributed to F Hirota.

12 recordsLinked to original sources
PubMed1989

X-ray crystallographic studies as to the calcification in the Hunter-Schreger bands of human enamel.

By analyzing integrated intensities of X-ray diffraction patterns and X-ray diffractograms obtained from the two zones of the Hunter-Schreger bands, it was deduced that the ratio of the sums of the integrated intensities and the degree of preferred orientation of the crystal aggregates in both zones of the bands were almost the same in value, but the fiber axes of the two zones were oriented in different directions. From these experimental observations and a consideration of the effect of the orientation of the enamel prisms relative to the incident X-ray beam, it is concluded that the two zones of the bands were calcified evenly and the light and dark zones on the microradiographs were caused by the difference in the orientation of enamel prisms.

Bicuspid↗
PubMed1988

[Interferon-alpha].

Among interferon (IFN)-alpha, beta, gamma, there are no differences in its clinical effects and toxicities. As to IFN-alpha, there are leukocyte IFN, lymphoblastoid IFN, recombinant IFN-alpha 2a, 2b, and 2c. Now we have largely completed the process of surveying for anticancer effects over the broad range of malignancies. However, the adequate method of administration, route, dose, and interval are not yet fully established. Dose response remains unanswered question with some contradictory results in in vitro and clinical reports. The actual mechanism responsible for its anticancer activity is still not known. The question of what variables to monitor in assessing adequate dosages of IFN remains unsolved. Several trials have examined the possibility of combining IFN with other treatment modalities including anticancer agents, BRMs, radiation, etc. It should be acknowledged that we remain at a very early stage in our understanding of IFN. In future, IFN may play an even larger role when used in an adjuvant setting or as part of multimodality cancer treatment.

Drug Evaluation↗
PubMed1987

[Interferon production in vitro].

Interferon production in vitro was induced by poly I: C and PHA in leukocytes obtained from patients with cancer, benign diseases and control subjects. The interferon response per lymphocyte was relatively constant in all groups. However, interferon production was slightly inhibited in patients receiving cancer chemotherapy. The peak response of interferon occurred at 48 hours after the initiation of the combined culture in each specimen. From our observations, it was suggested that interferon production in vitro seems to be useful marker for evaluation of effect of chemotherapy and or immunotherapy, and, furthermore, in the treatment of cancer patients with interferon inducers, there seems to be optimum BRM dose and optimum timing of administration.

Cell Wall Skeleton↗
PubMed1986

An explanation for the "two fiber axes" problem in human enamel by x-ray diffraction.

Since Thewlis found the "two fiber axes" patterns on x-ray diffractograms of human enamel in 1934, many investigators have studied this problem. However, a definite answer has not yet been obtained. The present detailed x-ray diffraction study showed that the "two fiber axes" patterns in human enamel were caused by reflections from the two zones of the Hunter-Schreger bands being recorded simultaneously on x-ray film, because we used an x-ray beam far larger in size than the width of the Hunter-Schreger bands.

Cuspid↗
PubMed1986

[Host factors in cancer chemotherapy].

Cancer grows in interaction with the host, that is, a host-tumor relationship exists. Investigations of host factors in patients receiving cancer chemotherapy are important, as they reveal the conditions in which a tumor response can develop. Furthermore, reliable host factors, if present, will be useful for quantitative evaluation of the effects of treatment. We have investigated the following three categories of host factors in relation to the effects of cancer chemotherapy and/or immunotherapy. CBC, and blood chemistries (44 parameters). Tumor markers; sialic acid, RNase, lysozyme, ferritin, IAP (immunosuppressive acidic protein), elastase I, AFP, CEA, POA, CA 19-9, CA 125, etc. Immunological parameters; lymphocyte, active T cell, T cell, B cell, IgG Fc receptor-positive T cell, lymphocyte blastogenesis stimulated by PHA, or concanavalin-A, ADCC activity, interferon production in vitro induced by poly I: C, or PHA, PPD skin test, immune complex, immunoglobulin G, A, and M, OKT series 3, 4, 8, 11, 4/8 ratio, antihuman HLA-DR, Leu 11, NK cell activity, etc. From our clinical observations, there were no significant differences in the pretreatment levels of these parameters between responders and non-responders. In responders, there was a tendency for the host factors to show greater degrees of improvement following treatment than in non-responders, but none proved to be reasonably reliable parameters for evaluating therapeutic effects. On the other hand, from our clinical observations on the advanced gastric cancer cases, life span showed a close correlation with tumor regression induced by cancer chemotherapy. Because of these facts, it is only natural that the clinical effects of chemotherapy are currently determined by definite tumor regression.

Humans↗
PubMed1984

[Pharmacokinetics of human interferons].

Interferon in the blood was rapidly cleared from the circulation after intravenous injection. Intramuscular injection of alpha-interferon caused low but stable interferon levels in the blood. However, in the case of beta-interferon, interferon was never detected consistently in the blood after intramuscular or subcutaneous administration. Intraarterial administration of beta-interferon also caused low but stable interferon levels in the blood. Our studies suggest that beta-interferon should be given intravenously to see clinical beneficial. No difference in pharmacokinetics was seen between natural interferon and recombinant interferon. No difference was also noted between partially purified interferon and highly purified interferon.

Animals↗
PubMed1983

[Phase II clinical trial of MCNU].

MCNU is a new derivative of nitrosourea and experimental studies have shown equal or superior activity to known nitrosourea compounds. Twenty one cases were entered into our clinical studies with a phase II study. Nineteen cases have had a several courses of prior chemotherapy. Four out of 21 cases achieved a partial response (each one of lymphoepithelioma, parotid gland cancer, recurrent uterine cancer and recurrent breast cancer). The major toxicity encountered during treatment was myelosuppression. Full recovery of myelosuppression was delayed and was seen six to eight weeks after each injections. These initial results justify further clinical investigations with MCNU.

Adolescent↗
PubMed1983

[Pancreatic oncofetal antigen (POA)].

Recently, there has been an increasing interest in the diagnostic and prognostic usefulness of tumor-associated antigen of embryonic and fetal origin. Many approaches have been attempted to make an early diagnosis of the pancreatic cancer, where a specific screening blood test for the pancreatic cancer is required. By using antiserum to fetal pancreas, Banwo et al, discovered an oncofetal antigen that was present in human fetal pancreas, pancreatic tumor tissue, and sera from patients with the pancreatic cancer. Pancreatic oncofetal antigen (POA) was considered to be an oncofetal antigen for human pancreas, and its measurement seemed to be useful in the diagnosis of pancreatic cancer. But elevated levels of POA were also observed in the serum of some patients with cancer of the stomach, lung, colon, or liver as well as in the serum of some pregnant women and others with certain benign conditions. In summary, combined assay with various tumor markers was considered to be useful for the diagnosis of pancreatic cancer.

Antigens, Neoplasm↗
PubMed1982

Prism arrangement in human cusp enamel deduced by X-ray diffraction.

Analysis of the many X-ray diffractograms obtained from the regions along the bands of Hunter-Schreger, and a series of X-ray patterns taken by tilting the specimen with respect to the incident X-ray beam over a wide range of tilt angles, showed that the fibre axis of the crystal aggregates in each zone of the bands not only deviated in opposite directions but also tilted at an angle of about 50 degrees with respect to the central axis of tooth enamel. Comparison with previous studies enabled a fundamental and simplified three-dimensional model of human cusp enamel to be constructed, consisting of two groups of spirally-arranged structure which would probably be elastic enough to fulfil its unique functions in occlusion and mastication.

Crystallization↗
PubMed1982

[Clinical experiences with pepleomycin].

From experimental observations, Peplomycin was expected to be more active against a variety of tumors and to be less toxic for the lung than the parent compound. An intermittent dose(10mg. twice a week) of peplomycin was tested in patients with malignant lymphoma or squamous cell carcinoma who had failed conventional treatment. There were two cases of CR and five cases of PR in twelve cases with malignant lymphoma, and two cases of PR in fourteen cases with squamous cell carcinoma. Out of 26 cases treated with peplomycin, fever was seen in ten cases(38.5%) and pulmonary complication was seen in five cases (19.2%). These data obtained from peplomycin treatment were compared with the results obtained from our previous experiences with bleomycin. Response rate, spectrum and frequency of side reactions of peplomycin treatment were substantially identical with those of bleomycin treatment. However, remission duration and life span were much longer in peplomycin treatment. In this respect, peplomycin seems to be superior than bleomycin to a certain extent.

Adult↗