The activation of cAMP-dependent protein kinase is directly linked to the inhibition of osteoblast proliferation (UMR-106) by parathyroid hormone-related protein

The present study was performed to compare the effect of parathyroid hormone-related protein (PTHrP) on the proliferation of osteoblastic osteosarcoma cells (UMR-106) with that of PTH and characterize the direct involvement of cAMP in the change of osteoblast proliferation by PTHrP. Human(h)PTHrP-(1-34) (10(-11)-10(-7)M) dose-dependently inhibited [3H]thymidine incorporation (TdR) in the same manner as hPTH-(1-34). The simultaneous addition of PTHrP and PTH at a maximal effective dose of 10(-7) M did not cause additive suppressive effect on cell proliferation. Rp-cAMPs, which has been recently shown to act directly as antagonist in the activation of cAMP-dependent protein kinase (PKA), dose-dependently (10(-6)-10(-4)M) antagonized PTHrP-induced suppression of TdR in the same manner as PTH. Present study indicated that PTHrP has the same effect on osteoblast proliferation as PTH and that the activation of PKA is directly linked to the change of osteoblast proliferation by PTHrP.     

Direct inhibitory effect of amino-terminal parathyroid hormone fragment [PTH(1-34)] on PTH secretion from bovine parathyroid primary cultured cells in vitro

We have examined the possibility of direct inhibitory effect of PTH(1-34) on PTH secretion in bovine parathyroid cells. As low as 10(-12) M PTH(1-34) completely inhibited low calcium (0.5 mM Ca2+)-stimulated PTH secretion by these cells. In the presence of 1.25 mM Ca2+, 10(-12) M PTH(1-34) inhibited PTH secretion by about 14.3% of the basal value, while 10(-11) M or higher concentration of PTH(1-34) showed potent inhibitory effects equivalent to the inhibitory action of high calcium concentration (2.5 mM Ca2+) on PTH secretion. At 2.5 mM Ca2+, as much as 10(-9) M PTH(1-34) failed to inhibit PTH secretion further. These results suggest that PTH(1-34) might directly, not via calcium concentration, inhibit PTH secretion by parathyroid cells and that a cooperative mechanism could exist between calcium and PTH(1-34) to inhibit PTH secretion.     

Purification and properties of extracellularβ-fructofuranosidases fromAureobasidium sp. ATCC 20524

Summary Two extracellular -fructofuranosidases (E-1 andE-2) fromAureobasidium sp. ATCC 20524, producing 1-kestose (1^F--fructofuranosyl-sucrose) from sucrose, were purified to homogeneity. Molecular weights of the enzymes were estimated to be about 304000 (E-1) and 315000 (E-2) Da by gel filtration. The enzymes contained 33% (w/w) (E-1) and 27% (w/w) (E-2) carbohydrate. TheK _m values for sucrose ofE-1 andE-2 andE-2 were 0.34 and 0.28 M, respectively. were 0.34 and 0.28 M, respectively. The enzymatic profiles of these enzymes were almost identical to intracellular enzymesP-1 andP-2 except for the differences in carbohydrate content andK _m values ofE-2 andP-2.     

Application of enzyme-linked immunosorbent assay for mass examination of strongyloidiasis in okinawa, Japan

The enzyme-linked immunosorbent assay was tested to evaluate whether it could be applicable in screening for mass examination of strongyloidiasis. A total of 2906 inhabitants in three areas (858 in Gushikawa Village, 849 in Nakazato Village and 1199 in Sashiki Town) were screened by the enzymatic assay and approximately 11–30% (11.8% in Gushikawa, 17.0% in Nakazato and 27.7% in Sashiki) were considered to be antibody positive. In the parasitological follow-up examinations of those who were antibody positive, actual infection was found in more than half (51%) the subjects. The overall infection rates estimated from the results reached 5.8% in Gushikawa, 9.1% in Nakazato and 14.0% in Sashiki (mean = 10.4%). The infection rates were significantly higher than those in previous surveys conducted in the same areas. The ELISA technique was found to be useful for strongyloidiasis screening and for seroepidemiological purposes in Okinawa.     

The effect of 1,25-dihydroxyvitamin D3 on human osteoblast-like osteosarcoma cell: modification of response to PTH

The influence of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on adenylate cyclase responsiveness in cultured osteoblastic cells was studied using a human osteosarcoma cell line SaOS-2. 1,25(OH)2D3 treatment had no effect on cell growth, cell protein and alkaline phosphatase activity. 1,25(OH)2D3 did not alter the basal production of cyclic AMP (cAMP) in intact cells, but the cAMP formation in response to parathyroid hormone (PTH), isoproterenol (ISO) and cholera toxin was attenuated by 1,25(OH)2D3. The response to forskolin, however, was unaffected by 1,25(OH)2D3 treatment. Islet activating protein failed to modify these 1,25(OH)2D3 effect. In cell free experiments, 1,25(OH)2D3 showed similar effect--that is, PTH and ISO-stimulated adenylate cyclase activity were attenuated, but forskolin-stimulated adenylate cyclase was unaffected. 1,25(OH)2D3 treatment had no effect on the kinetics of PTH binding to PTH receptor and on the ADP ribosylation of GTP stimulatory binding protein (Gs) in SaOS-2 cells. According to these results, 1,25(OH)2D3 appeared to change the coupling of Gs with adenylate cyclase, but does not affect receptor, Gs and adenylate cyclase themselves, nor GTP inhibitory binding protein.     

Kinetics of the Unrolling of the Second Leaves Detached from Rice Seedlings by Blue Light

Unrolling due to blue light (B) irradiation of the second leavesdetached from 8-day-old rice (Oryza saliva L.) seedlings wassimilar to that reported previously for nondetached leaves.The effect of B was counteracted by irradiation with red light(R). The counteracting effect of R was reversed by subsequentirradiation with far-red light (FR). When the detached leaf was irradiated with B passed througha 1-mm-wide slit 5, 8, 10, 12 or 15 mm from the leaf tip, irradiation10 mm from the leaf tip was the most effective. The effect of a 1 mm-wide-B irradiation 10 mm from the leaftip was counteracted by a 1 mm-wide-R irradiation at the sameposition, but not by irradiations at the other points. The counteractingeffect of R was reversed by a 1 mm-wide-FR irradiation at thesame position. This suggests that the excitation or the reactionof the B photoreceptor(s) is affected directly by the PFR formof phytochrome. The dose-response curve for the unrolling caused by B showeda simple Bunsen-Roscoe relation without two peaks, which differsfrom that for the phototropism in Avena caused by B. (Received August 21, 1980; Accepted December 20, 1980)     

Light and electron microscopical combined staining by immunohistochemical and enzyme histochemical methods using rat prolactin-secreting pituitary tumours

Summary Combined immunohistochemical staining (IHCS) and enzyme histochemical staining (EHCS) methods for light microscopy (LM) and electron microscopy (EM) are reported, using oestrogeninduced rat pituitary tumours. For LM, combined staining for alkaline phosphatase and acid phosphatase by EHCS, using the azo dye method, and for prolactin and ACTH by IHCS, using the enzyme-labelled antibody method, gave the best results on 1 m glycol methacrylate sections. For EM, combined staining by EHCS on 30 m tissue sections followed by IHCS for prolactin on ultrathin Epon sections (enzyme-labelled antibody method) provided acceptable results. By these combined staining methods, the neoplastic prolactin cells were shown to have close affinity to rich alkaline phosphatase-positive capillaries and to possess an alkaline phosphatase-positive cell membrane. Furthermore, they revealed acid phosphatase-positive lysosomal and secretory granules. These combined staining methods may be valuable in studies on the actual functional status of cells.     

Recessive and dominant genes controlling inducible sexual agglutinability in Saccharomyces cerevisiae

Summary We have characterized the two dominant genes, IND 1 and IND 2, responsible for inducible sexual agglutinability. The strains carrying these genes differ from the inducible strains carrying the recessive gene, saa 1 in the following points. The former strains produce agglutination substance at 22°, 28°, and 37° C only in response to sex pheromone of the opposite mating type, but the latter strains produce the substance constitutively without the pheromone at 22° C, only in response to the pheromone at 28° C, and do not produce the substance, even in the presence of the pheromone, at 37° C.We suggest that strains carrying one of the dominant, inducible genes are wild type and have a pheromone-controlled regulatory system of sexual agglutinability.     

High-dose zolpidem abuse in a patient with insomnia comorbid with major depressive disorder

Sleep and Biological Rhythms - A 39-year-old married woman was referred to a psychiatry outpatient clinic for treatment of major depressive disorder (MDD). The dose of zolpidem she had been taking...     

Rapid Severing and Motility of Chloroplast-Actin Filaments Are Required for the Chloroplast Avoidance Response in Arabidopsis

Phototropins (phot1 and phot2 in Arabidopsis thaliana) relay blue light intensity information to the chloroplasts, which move toward weak light (the accumulation response) and away from strong light (the avoidance response). Chloroplast-actin (cp-actin) filaments are vital for mediating these chloroplast photorelocation movements. In this report, we examine in detail the cp-actin filament dynamics by which the chloroplast avoidance response is regulated. Although stochastic dynamics of cortical actin fragments are observed on the chloroplasts, the basic mechanisms underlying the disappearance (including severing and turnover) of the cp-actin filaments are regulated differently from those of cortical actin filaments. phot2 plays a pivotal role in the strong blue light–induced severing and random motility of cp-actin filaments, processes that are therefore essential for asymmetric cp-actin formation for the avoidance response. In addition, phot2 functions in the bundling of cp-actin filaments that is induced by dark incubation. By contrast, the function of phot1 is dispensable for these responses. Our findings suggest that phot2 is the primary photoreceptor involved in the rapid reorganization of cp-actin filaments that allows chloroplasts to change direction rapidly and control the velocity of the avoidance movement according to the light’s intensity and position.