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Biomedical subjects

M Takahama

Publications and source records attributed to M Takahama.

At least 73 records · Page 4Linked to original sources
PubMed1991

Salmon calcitonin induces pituitary tumor in rats.

Calcitonin is widely used in the treatment of post-menopausal osteoporosis. The present study was designed to investigate the effects of salmon calcitonin (SCT) on the incidence of the pituitary tumors in Sprague-Dawley (SD) rats. Subcutaneous injections of SCT at a dose of 160 IU/kg/day for 6 months reduced body weight and induced one pituitary hyperplasia and three pituitary adenomas in 4 of 5 animals, while 5 controls did not show any changes. Prolactin-positive cells were located at the periphery of the affected pituitaries adjacent to the prolactin-negative adenomas. In addition, serum concentrations of prolactin and TSH were lower than in the controls, although serum calcium or LH levels were not significantly different from the controls. Among 7 animals treated with SCT for 6 months followed by no medication for another 6 months, 5 adenomas were detected, one of which had invasive growth toward the adjacent tissue, whereas only one adenoma was found in 9 controls. These results suggest that SCT administration at a high dose may induce the formation of pituitary adenoma, or may accelerate the development of spontaneous pituitary adenomas, some of which show frequent mitotic figures and invasive growth into the surrounding tissue, possibly resulting in malignant transformation. This indicates the need for caution in considering whether calcitonin injections into patients with osteoporosis as well as Paget's disease may induce such pituitary tumors.

Adenoma↗
PubMed1991

[A case of infantile Sertoli cell tumor].

A case of infantile Sertoli cell tumor of the testis is presented. A 2-year-old child visited our hospital with the complaint of painless swelling of the left scrotal content. A solid tumor was demonstrated in the left testis by scrotal echography. Physical and laboratory examinations were within normal limits and alpha-fetoprotein and beta-HCG were not elevated. The left testis was removed. The tumor sized 3.0 x 3.0 x 2.2 cm and weighted 14.5 g. Pathohistological diagnosis was benign Sertoli cell tumor. Tumor cells were vimentin positive and TM-1 reactive antigen positive and revealed electronmicroscopically some features of Sertoli cells such as intermediated microfilament, rich lysosomes and interdigitation between adjacent cells. The patient was well with no evidence of diseases one and a half years after the operation.

Age Factors↗
PubMed1988

Hematoporphyrin/DAPI staining: simplified simultaneous one-step staining of DNA and cell protein and trial application in automated cytological screening by flow cytometry.

We describe a procedure for simplified, simultaneous one-step staining in 10 min for DNA and cell and tissue proteins using a newly developed staining solution containing 0.03% hematoporphyrin (HP) with 0.001% DAPI [or with Hoeschst 33342 (HO)]. These HP/DAPI or HP/HO solutions were especially developed to facilitate a trial of automated cancer cell screening on sputum samples using flow cytometry. Under UV light (365 nm) with fluorescence microscopy, HP/DAPI-stained cells showed red fluorescence (max. 670 nm) of cytoplasm and simultaneous blue fluorescence (max. 470 nm) of nuclei. The distance between the maximum peak of fluorescence spectra of DNA and that of protein was as large as 200 nm, and there was no detectable overlapping of each spectrum at the photometric filter range, which provided accurate measurement of DNA and protein. On flow cytometry, a single UV beam (370 nm) from the argon laser was used for excitation of both dyes. Measurement of DNA was done using a 470-nm bandpass filter and of protein using a 640-nm longpass (or 670-nm bandpass) filter. Reflecting the undetectable overlapping of the fluorescence spectra of protein and DNA, normal diploid cells in sputum revealed horizontal distributions along the 2C level on the dot-plot display of flow cytometry, which made sorting of abnormal hyperdiploid cells and cancer cells easier.

Animals↗
PubMed1988

Arousal-related changes in dark focus accommodation and dark vergence.

Dual-innervation theory suggests that dark focus (DF; the accommodation in effect in total darkness) reflects a balance between sympathetic and parasympathetic inputs. Since it is assumed that relaxation of accommodation is sympathetically innervated, and that accommodative increases are parasympathetically innervated, stimulation that leads to sympathetic activation should produce lower DF values than is the case when there is greater parasympathetic influence. In addition, the synkinesis between accommodation and vergence, and the known effects of fatigue, injury and drugs on fusion, promote an interest in the effects of arousal on dark vergence (DV; the vergence in effect in total darkness). Twenty-three young adult males experienced a variety of stimulus conditions. The conditions, selected because of their likely autonomic effects, included deep muscle relaxation, cold pressor and mental activity, among others. During each condition, measurements were made of DF (with a laser optometer) and DV (with a Nonius alignment system). Results for DF were consistent with dual innervation theory; manipulations expected to induce sympathetic activation (eg, cold pressor) produced lower DF values than did conditions expected to induce more parasympathetic (or less sympathetic) activation (eg, relaxation). DV tended to be influenced in the opposite direction, in that relaxation led to smaller DV angles than did the other conditions. Several analyses confirmed a lack of synkinesis between accommodation and vergence during darkness.

Accommodation, Ocular↗
PubMed1987

Effects of relaxation and aversive visual stimulation on dark focus accommodation.

There is evidence that sympathetic innervation induces decreases in accommodation or accommodation amplitude. If so, emotional stress that produces sympathetic activation should induce similar changes in accommodation. In two experiments, dark focus accommodation was assessed following deep relaxation and after subjects looked at gruesome slides. Results showed that stress exposure led to lower dark focus values than did relaxation. Further, the degree to which dark focus was affected depended on subjects' levels of perceived arousal, and on the degree of stressfulness represented by the slides. It was concluded that psychological stress can produce predictable changes in accommodation, changes most parsimoniously understood in terms of autonomic innervation of the ciliary body.

Accommodation, Ocular↗
PubMed1984

Calcium pyrophosphate dihydrate deposits in the cervical ligamenta flava causing myeloradiculopathy.

Three cases of cervical myeloradiculopathy associated with multiple calcified nodules containing identified calcium pyrophosphate dihydrate (CPPD) crystals in the ligamenta flava are described, with a comprehensive review of the 12 cases of this entity reported to date. The disease is characterized by: 1) oval or triangular areas of radiodensity in the posterior aspect of the cervical canal as seen in the lateral x-ray films and laminograms; 2) hemispherical areas of high density located almost symmetrically in the paramedial portion of the posterior spinal canal on computerized tomography scans; and 3) CPPD crystals in the nodules. It occurs independently or in association with cervical spondylosis or ossification of the posterior longitudinal ligament.

Aged↗
PubMed1982

Dense cerebellopontine epidermoid cyst.

A diffuse, bubblelike, high-density epidermoid cyst of the cerebellopontine angle is described as seen on CT scanning. The high density was attributed to high protein concentration of the cystic fluid due to a proliferative and exudative defense reaction to a "minor leak" of the lipidic material through the capsule, verified by Sudan black B stain. A description of the appearance of the tumor on computerized tomography, based on 42 cases of intracranial epidermoids reported in the literature, is discussed. To our knowledge this is the first morphological documentation of spontaneous leakage of cyst contents, and the second report in the English literature of a dense intracranial epidermoid.

Adult↗
PubMed1979

Gait patterns of the diseased knee joint.

Biomechanical gait analyses were carried out on 21 patients in whom 11 had bilateral and 10 unilateral disease of the knee joint. Similar studies, for use as controls were made on 7 normal volunteers. The data, on which the analyses were based, were obtained using a force plate, a xylophone plate, electromyography and electrogoniometry. The equipment and methods used are described. The results suggest that the locomotion mechanism in patients with disease of the knee joints is affected adversely by severity of pain and instability. Alterations observed in the gait characteristics of such patients comprise decreased sagittal plane knee motion during stance phase, increased electromyographic activities of the quadriceps and the hamstrings during stance phase and increase in the lateral component of ground reaction force. Functional requirements of the knee joint include stable support of body weight and a wide range of movement. These features make the knee particularly susceptible to the deleterious effects of traumatic injury, inflammatory and degenerative disease. The purposes of this study are to characterise the gait patterns of patients with such disease of the knee joints and to identify the mechanisms of these abnormal patterns. With these intentions, biomechanical analyses were carried out on information obtained from the use of force plates, electrogoniometry and electromyography.

Adult↗
PubMed1975

Giant occipital hemangioendothelioma with thrombocytopenia, anemia, and hypofibrinogenemia. Case report.

The authors describe the total excision of a huge occipital hemangioendothelioma in an infant with thrombocytopenia, hypofibrinogenemia, and anemia; treatment was followed by normalization of platelet count, blood cell count, and level of fibrinogen. Histological and clincial studies support the concept the disseminated intravascular coagulation was related to the thrombocytopenia and coagulation deficits found in this case.

Afibrinogenemia↗
PubMed1975

[Giant occipital hemangioendothelioma with thrombocytopenia, anemia and hypofibrinogenemia treated by total excision (author's transl)].

An infant with a large occipital hemangioendothelioma with thrombocytopenia, anemia, and hypofibrinogenemia--Kasabach-Merritt syndrome--was reported. The case, a male neonate is unique, for this is the first report with this syndrome in whom the large hemangioma was noted at birth on the midocciput simulating the occipital encephalomeningocele. With the development of thrombocytopenia of 84,000 per mm3, hypofibrinogenemia of 92 mg/dl, anemia (erythrocyte 193 X 10(4) per mm3, hemoglobin 5.9 g/dl, hematocrit 16 vol%), hepato-splenomegalia, enlargement and bluish discoloration of the tumor noted on the 21/2 months of life, total excision was intended prior to the expected occurence of the systemic purpura. The patient received fresh whole blood transfusion immediately prior to surgery, and the total excision was successfully performed. Excessive bleeding was not encountered. Abrupt rise in the platelet count, red blood cell count, hemoglobin and hematocrit to normal range was noted at the first postoperative day; he was discharged on the 17th day after surgery. Nineteen months' follow-up showed normal hematologic findings with good somatic and mental development. The specimen weighing 250 g. revealed benigh hemangioendothelioma. Silver impregnation demonstrated lobular aggregates of small vascular channels. Papillary projection of interstitial cells into the lumen, reaction of the endothelium of the vessels, newly formed thrombus, ishemic necrosis and hemorrhage, hyaline degeneration of interstitial tissue were noted. These findings suggested the disseminated intravascular coagulation within the tumor followed by fibrinolysis accounts for loss of blood corpuscles, platelet, fibrinogen and clotting factors, which leads ultimately to the consumption coagulopathy and diffuse bleeding.

Afibrinogenemia↗