Biomedical subjects
Publications and source records attributed to T Tsuruhara.
The seasonal distribution of birth dates of 31 patients with sporadic cretinism due to thyroid dysgenesis was analyzed in Osaka area for 14 years. The incidence was statistically high in the summer months. A hypothesis that some environmental factors such as viral infection may cause the disease is proposed.
A case of transient hyperthyrotropinaemia was found by mass screening for neonatal hypothyroidism using the paired TSH assay method. The patient was a baby boy born at term after a normal pregnancy who grew without any abnormal signs or symptoms. For the first 7 months after birth, his serum TSH was abnormally high while his total serum T4, T3, and free T4, T3 were within normal limits, exept for slightly low free T4 level at 7 months. The raised serum TSH decreased spontaneously to within normal limits after he was 9 months old.
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During early summer 1975 and spring 1976, outbreaks of acute gastroenteritis were reported from primary schools and other institutions in several districts of Japan. Outbreaks occurred in an explosive manner resembling mass food poisoning from a school lunch. The majority of patients were in the age group 6-14 years. Clinical features were generally mild, consisting of vomiting and/or diarrhea, often with low-grade fever. Reovirus-like agents in the feces were found in 27 (44%) of 62 patients. The virus found in feces of schoolchildren with acute gastroenteritis (SCGV) was related morphologically as well as serologically, not only to the agent found in infantile gastroenteritis (IGV), but also to neonatal calf diarrhea virus (NCDV). A slight difference in antigenicity between SCGV and IGV as suggested by cross complement fixation (CF) remains to be elucidated. About one-half of paired sera from 54 patients showed a significant rise in CF antibody against SCGV and/or NCDV. The pattern of neutralizing (NT) antibody against NCDV in patients' sera was similar to that of CF antibody. Most children studied had a titer of 1:4 or greater of CF and/or NT antibodies to SCGV and NCDV in acute sera. The relationship between acute gastroenteritis associated with reovirus-like agent in infants and that in schoolchildren is discussed.
This paper is a report of studies on Cotia virus; this had been first isolated in 1965 in Brazil and was subsequently shown to be a poxvirus. Cotia virus grew in a wide range of cell cultures and on the chick chorioallantois (CAM), Its growth characteristics are similar to those of other poxviruses. Microscopy showed virus factories or type B inclusions appearing before infectious progeny virus could be demonstrated. Type A inclusions appeared later, after development of progeny virus; these were shown by electron microscopy to differ from the type A inclusions of cowpox and other poxviruses and they have been termed Cotia bodies. Immunofluorescent staining also showed ring structures which appeared before the development of Cotia bodies. The growth of Cotia virus in human embryo lung (HEL) cells was sensitive to inhibitors of DNA and protein synthesis but was resistant to a concentration of rifampicin which inhibited vaccinia virus. Sharing of antigens between the Cotia virus and vaccinia virus was shown by gel precipitation tests and immunofluorescent staining. There was no cross neutralization between Cotia virus and vaccinia virus nor did anti-Cotia sera neutralize representatives of other poxvirus groups.
Human type "O," guinea pig, and chicken erythrocytes were agglutinated by enterovirus type 70 at 4 degrees C or room temperature. A hemagglutination inhibition test, using human "O" erythrocytes, is described for the serological diagnosis of acute hemorrhagic conjunctivitis caused by enterovirus type 70.
A simple and reliable method of paired TSH assay was developed and used in screening for neonatal primary hypothyroidism. In this method, a paired assay is first done. Equal parts of the extracts of dried blood spots on filter paper (9 mm diameter) from two infants 4-7 days old are combined and assayed for TSH by double antibody RIA. If the value obtained is over the cut-off point, the extracts are assayed separately for TSH in a second assay to identify the abnormal sample. Two systems, A and B, with different cut-off points were tested. On the basis of reference blood samples (serum levels of TSH, 80 microU/ml in system A and 40 microU/ml in system B), the cut-off point was selected as follows: upper 5 (A) or 4 (B) percentile in the paired assay and values of reference blood samples in the second individual assay. Four cases (2 in A and 2 in B) of neonatal primary hypothyroidism were found among 25 infants (23 in A and 2 in B) who were recalled from a general population 41,400 infants (24,200 in A and 17,200 in B) by 22,700 assays. This paired TSH neonatal hypothyroidism.
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Discrepancies between adenosine 3':5'-cyclic monophosphate (cAMP) and steroid production have been frequently observed in isolated target cells stimulated by low concentrations of trophic hormone. This dissociation is particularly marked in the interstitial cells of the testis, where testosterone production is elicited by gonadotropin concentrations in the picomolar range. Because of these observations, and a disparity between steroidogenesis and protein kinase (ATP: protein phosphotransferase, EC 2.7.1.37) activation in Leydig cells, the role of cAMP as a mediator of the acute steroidogenic response has been questioned. This problem has been further analyzed by assay of free and occupied cAMP-binding sites of the regulatory subunit of protein kinase in basal and hormone-stimulated cells. Free sites were measured by a [(3)H]-cAMP-binding assay, and occupied sites were measured by radioimmunoassay of endogenous cAMP eluted from receptor protein. After stimulation of purified Leydig cells with 0.1-10 pM human chorionic gonadotropin, a dose-dependent decrease in available [(3)H]cAMP-binding sites was observed, with no change in binding affinity. The reduction in cAMP-binding sites was equivalent to the increase in occupancy of cAMP receptors by endogenous nucleotide formed during gonadotropin action. Fractional occupancy of cAMP receptors rose progressively from basal values of 0.2-0.40 to full saturation as intracellular cAMP rose 10- to 30-fold during hormone stimulation. The testosterone dose-response curve was coincident with the initial part of the cAMP-receptor occupancy curve. These changes in endogenous cAMP binding to the regulatory subunit were accompanied by a significant increase in protein kinase activity in gonadotropin-stimulated Leydig cells. These observations provide direct evidence for the role of cAMP and protein kinase during hormonal activation of steroidogenesis in the Leydig cell by low concentrations of gonadotropin.
Purification of specific endocrine cells from mixed populations after dispersion of target tissues is important for detailed analysis of mechanisms of hormone action. A simple method for rapid isolation of endocrine cells with retention of biological integrity, has been developed by centrifugation in density gradients formed with Metrizamide. By this procedure, highly purified Leydig cells retaining morphological and biochemical characteristics were obtained. Such preparations bound 20, 300+/-3, 100 molecules of hCG per cell with affinity of 1.1+/-0.25 X 10(10) M-1. During incubation with hCG, cyclic AMP and testosterone responses of purified Leydig cells were considerably increased, and hCG concentrations as low as 0.2 pM caused activation of cAMP-dependent protein kinase.
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A method for measuring thyrotropin (TSH) in eluates of dried blood samples on filter paper was evaluated and improved as a screening test for neonatal hypothyroidism. A linear relationship between the volume of eluate and the TSH value and good recoveries of endogenous TSH (104%) and added TSH (89%) were obtained, indicating that TSH in dried blood was extracted well by overnight elution and determined accurately by radioimmunoassay. The TSH content in the central portion of a spot was less (71%) than that in the peripheral portion. The TSH in dried blood samples on filter paper was stable at 4 degrees C, room temperature (about 25 degrees C) or 37 degrees C for 1 month. The TSH values of eluates were correlated with those of whole blood (r = 0.90) and serum (r = 0.81). Cases of primary hypothyroidism cound be readily differentiated from normal subjects by this method, even when eluates of their blood were combined with those of normal blood for assay of TSH.
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