Fracture liaison services for osteoporosis in the Asia-Pacific region: current unmet needs and systematic literature review.

The analysis aimed to identify the treatment gaps in current fracture liaison services (FLS) and to provide recommendations for best practice establishment of future FLS across the Asia-Pacific region. The findings emphasize the unmet need for the implementation of new programs and provide recommendations for the refinement of existing ones. The study's objectives were to evaluate fracture liaison service (FLS) programs in the Asia-Pacific region and provide recommendations for establishment of future FLS programs. A systematic literature review (SLR) of Medline, PubMed, EMBASE, and Cochrane Library (2000-2017 inclusive) was performed using the following keywords: osteoporosis, fractures, liaison, and service. Inclusion criteria included the following: patients ≥ 50 years with osteoporosis-related fractures; randomized controlled trials or observational studies with control groups (prospective or retrospective), pre-post, cross-sectional and economic evaluation studies. Success of direct or indirect interventions was assessed based on patients' understanding of risk, bone mineral density assessment, calcium intake, osteoporosis treatment, re-fracture rates, adherence, and mortality, in addition to cost-effectiveness. Overall, 5663 unique citations were identified and the SLR identified 159 publications, reporting 37 studies in Asia-Pacific. These studies revealed the unmet need for public health education, adequate funding, and staff resourcing, along with greater cooperation between departments and physicians. These actions can help to overcome therapeutic inertia with sufficient follow-up to ensure adherence to recommendations and compliance with treatment. The findings also emphasize the importance of primary care physicians continuing to prescribe treatment and ensure service remains convenient. These findings highlight the limited evidence supporting FLS across the Asia-Pacific region, emphasizing the unmet need for new programs and/or refinement of existing ones to improve outcomes. With the continued increase in burden of fractures in Asia-Pacific, establishment of new FLS and assessment of existing services are warranted to determine the impact of FLS for healthcare professionals, patients, family/caregivers, and society.

Adenosine 3',5'-monophosphate-dependent protein kinase from brain.

Adenosine 3',5'-monophosphate at a concentration of 5 x 10(-7) mole per liter causes a 400 percent increase in the rate of phosphorylation of histone catalyzed by a partially purified enzyme preparation from rabbit brain. The data provide the first direct evidence of a biochemical action of adenosine 3',5'-monophosphate in the brain.

Cytidine 3',5'-monophosphate phosphodiesterase: decreased activity in the regenerating and developing liver.

A decrease in the activity of the enzyme cytidine 3',5'-monophosphate (cyclic CMP) phosphodiesterase was noted in the regenerating liver of young rats as early as 8 hours after partial hepatectomy, with a maximum decrease occurring 12 hours after the surgery. In comparison, in old rats which showed a slower liver growth, the maximum decrease in the activity of cyclic CMP phosphodiesterase was smaller and occurred at a much later time (2 days after surgery). A similar decrease in the enzyme activity was observed in the fetal liver of guinea pigs. These findings suggest that regulation of tissue concentration of cyclic CMP may be crucial for the regeneration and development of the liver.

Effects of thioether phospholipid BM 41.440 on protein kinase C and phorbol ester-induced differentiation of human leukemia HL60 and KG-1 cells.

The synthetic thioether phospholipid BM 41.440 (1-S-hexadecyl-2-methoxymethyl-rac-glycero-3-phosphocholine) was found to inhibit protein kinase C (PKC) activity competitively with respect to phosphatidylserine, with an apparent Ki value of about 6.4 microM. The agent also inhibited the enzyme activated by diolein or 12-O-tetradecanoylphorbol-13-acetate (TPA), without affecting binding of [3H]phorbol-12,13-dibutyrate to the enzyme. Myosin light chain kinase and cAMP-dependent protein kinase were not inhibited by BM 41.440, indicating a specificity of the action of the agent. BM 41.440 partly blocked the TPA-induced depletion of soluble PKC in HL60 and KG-1 cells (responsive to the differentiating effect of TPA) but not in K562 cells (resistant to the TPA effect). The thioether inhibited the phosphatidylserine/Ca2+-dependent phosphorylation of several common proteins in the solubilized homogenates of HL60 and KG-1 cells, and that of apparently distinct proteins in the preparation of K562 cells. The TPA-induced differentiation of HL60 and KG-1 cells was inhibited by BM 41.440 at a concentration inhibitory to PKC, but differentiation of HL60 cells promoted by dimethyl sulfoxide, retinoic acid, and 1,25-dihydroxyvitamin D3, on the other hand, was not affected. The present data suggested that PKC inhibition might partly account for the antineoplastic effect of BM 41.440, and that the agent could be useful in studying involvements of the PKC system in cellular processes.

Effects of selenium compounds on phospholipid/Ca2+-dependent protein kinase (protein kinase C) system from human leukemic cells.

Selenium compounds (selenium dioxide, selenious acid, and selenic acid) were found to inhibit phospholipid/Ca2+-dependent protein kinase (protein kinase C) and the phorbol ester-stimulated phosphorylation of endogenous substrate proteins from HL60 cells. Kinetic analysis indicated that selenium dioxide (SeO2) inhibited the enzyme noncompetitively with respect to phosphatidylserine (apparent Ki, 60 microM) and Ca2+ (apparent Ki, 68 microM). The inhibitory effect of SeO2 on protein kinase C was additive to that of another inhibitor of the enzyme (alkyl-lysophospholipid) when present together. SeO2 was also equally inhibitory to myosin light chain kinase, a calmodulin/Ca2+-dependent class of protein kinase. It, however, affected only very slightly cyclic adenosine 3':5'-monophosphate-dependent protein kinase. It is suggested that inhibition of Ca2+-dependent reactions might be related to the anticarcinogenic property of selenium.

Effects of phorbol ester on translocation and down-regulation of protein kinase C and phosphorylation of endogenous proteins in human acute myeloid leukemia cell line KG-1 and its phorbol ester-resistant subline KG-1a.

12-O-Tetradecanoylphorbol-13-acetate (TPA) induced decreases in the catalytic activity and immunoreactivity of protein kinase C (PK-C) in the soluble fraction, accompanied by increases in their activities in the particulate fraction, of a human myeloid leukemia cell line KG-1. TPA also caused a similar down-regulation and translocation of PK-C in KG-1a, a cloned subline shown to be resistant to the differentiating effect of TPA. The activity levels of enzyme in the soluble and particulate fractions from KG-1 cells, however, were about three times higher than those from KG-1a cells. Immunocytochemical studies showed that, when KG-1 cells were treated with 10 nM TPA for 30 min, PK-C was translocated to the plasma membrane in the adherent subpopulation of cells, whereas the enzyme remained largely in the cytoplasm and perinuclear area of the nonadherent cells. TPA, in contrast, caused a PK-C translocation primarily to the perinuclear region in KG-1a cells. Phosphorylation patterns of PK-C substrate proteins in the two cell lines were similar, except that phosphorylation of the Mr 33,000 and 97,000 proteins were predominant in KG-1 and KG-1a cells, respectively. The present findings showed existence of certain differential effects of TPA on the PK-C system in the two leukemia cell lines, suggesting a molecular basis for the selective resistance of KG-1a cells to the differentiating action of TPA.

Phospholipid-sensitive Ca2+-dependent protein phosphorylation system in various types of leukemic cells from human patients and in human leukemic cell lines HL60 and K562, and its inhibition by alkyl-lysophospholipid.

Phospholipid-sensitive Ca2+-dependent protein kinase (PL-Ca-PK), its endogenous substrate proteins, and regulation of the enzyme system by an antitumor agent alkyl-lysophospholipid were investigated in various types of leukemic cells (chronic myelocytic, acute myelocytic, and acute monocytic) from patients and in two cultured human leukemic cell lines (HL60 and K562). Exceedingly high levels of PL-Ca-PK, largely localized in the particulate fraction, were found in all types and lines of leukemic cells; much lower levels of cyclic adenosine 3':5'-monophosphate-dependent protein kinase and cyclic guanosine 3':5'-monophosphate-dependent protein kinase were also found. Although numerous and similar endogenous substrates for PL-Ca-PK were found in all cell types and lines examined, substrates specific for certain leukemic cells appeared to be present. Substrate proteins for calmodulin-sensitive Ca2+-dependent protein kinase, cyclic adenosine 3':5'-monophosphate-dependent protein kinase, and cyclic guanosine 3':5'-monophosphate-dependent protein kinase, in comparison, were much fewer or undetected. The PL-Ca-PK activity and the phosphatidylserine-Ca2+-stimulated phosphorylation of endogenous proteins from leukemic cells were inhibited by alkyl-lysophospholipid, which acted as a competitive inhibitor of the phospholipid cofactor of the enzyme. The findings suggested that the PL-Ca-PK system is a predominant protein phosphorylation system in leukemic cells and that this enzyme system may represent a site of cytotoxic action of alkyl-lysophospholipid.

Inhibition of protein kinase C, (sodium plus potassium)-activated adenosine triphosphatase, and sodium pump by synthetic phospholipid analogues.

The effects and modes of action of certain antineoplastic phospholipid analogues (racemic 1-O-octadecyl-2-O-methyl glycero-3-phosphocholine, BM 41.440, JH-1, CV-3988, and HePC) on (sodium plus potassium)-activated adenosine triphosphatase (Na,K-ATPase) and sodium pump activities were investigated. Inhibition of Na,K-ATPase in purified rat brain synaptosomal membranes by these lipids, in contrast to ouabain, was subject to membrane surface dilution and unaffected by whether the reaction was started with KCl, NaCl, or ATP. Kinetic analysis indicated that the analogues, again dissimilar to ouabain, were likely to interact directly or indirectly with sodium-binding sites of Na,K-ATPase located at the intracellular surface of the plasma membrane, a conclusion also supported by studies using the inside-out vesicles of human erythrocyte membranes. The studies also showed that ouabain (but not the lipids) increased the affinity constant of Na,K-ATPase for K+, whereas the lipids (but not ouabain) increased that for Na+. The lipids also inhibited 86Rb uptake by intact human leukemia HL60 cells at potencies quite comparable to those seen for inhibition of purified protein kinase C or Na,K-ATPase. It is suggested that Na,K-ATPase (sodium pump) might represent a hitherto unrecognized site of action for the lipid analogues, and that the antineoplastic effects of the agents might be due to, in part, inhibition of both protein kinase C and Na,K-ATPase and perhaps other membrane-associated enzymes.

Immunocytochemical evidence for phorbol ester-induced directional translocations of protein kinase C in HL60, K562, CHO, and E7SKS cells: possible role in differentiation.

The effects of phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) on the directions of protein kinase C (PKC) translocation in two leukemic cell lines (HL60 and K562) and two fibroblastic cell lines (CHO and E7SKS), related to their susceptibility to the differentiating effect of TPA, were examined. Immunocytochemical evidence indicated that TPA induced a redistribution (outward) of PKC to the plasma membrane in TPA-sensitive HL60 cells, whereas it caused a translocation (inward) of the enzyme to the nucleus or the perinuclear region in K562, CHO, and E7SKS cells, which are resistant to TPA in terms of cell growth and differentiation. Immunoblot analysis of the nuclear proteins from K562 cells revealed that TPA induced an increase in the amount of immunoreactive proteins. TPA, however, did not increase the amount of these immunoreactive species in nuclei isolated from CHO and E7SKS cells, indicating that the translocated PKC was associated only with perinuclear structures of the TPA-treated cells. It is suggested that directional redistribution of PKC to the plasma membrane, as opposed to the nuclear and perinuclear region, might represent an early event required for the TPA-induced differentiation and maturation of HL60 cells.

Differential effects of various protein kinase C activators on protein phosphorylation in human acute myeloblastic leukemia cell line KG-1 and its phorbol ester-resistant subline KG-1a.

Human myeloid leukemia KG-1 cells are induced to differentiate to macrophage-like cells by tumor-promoting phorbol esters, such as 12-O-tetradecanoylphorbol-13-acetate (TPA). Cells from the cloned subline, KG-1a, unlike the parental line, are resistant to the differentiating effect of TPA. In the present studies, we investigated in these cells protein phosphorylation stimulated by various protein kinase C activators, including 1-oleoyl-2-acetylglycerol in the presence of the diacylglycerol kinase inhibitor R59022, TPA, mezerein, and bryostatin. All the agents stimulated, to a greater extent and with a higher potency, phosphorylation of several proteins in KG-1 cells than in KG-1a cells. On the other hand, these agents markedly stimulated phosphorylation of other proteins in KG-1a cells compared to that in KG-1 cells. The findings indicated that the actions of the diacylglycerol, 1-oleoyl-2-acetylglycerol, and the non-metabolizable activators (TPA, mezerein, and bryostatin) were very similar but not fully equivalent; and that KG-1a cells exhibited altered (increased or decreased) phosphorylation patterns, perhaps related to the TPA resistance characteristic of this subline of cells.

Ontogenetic changes in levels of phosphodiesterase for adenosine 3':5'-monophosphate and glucosine 3':5'-monophosphate in the lung, brain and heart from guinea pigs.

Changes in tissue levels of the low Km phosphodiesterase for adenosine 3':5'-monophosphate (cyclic AMP) and guanosine 3':5'-monophosphate (cyclc GMP) in the lung, liver, heart and brain from developing guinea pigs were studied. It was found that the contents of the soluble (cytosol) phosphodiesterase for both cyclic AMP and cyclic GMP were higher in the lung from the fetus than from the neonate and adult. The ontogenetic changes seen in the liver were qualitatively similar to thos in the lung with respect to cyclic GMP hydrolysis, while a reversed pattern of change was noted in the brain. The level of cyclic AMP phosphodiesterase was highest in the fetal heart. Throughout the fetal stage, the levels of the enzyme for cyclic GMP hydrolysis were higher than those for cyclic AMP in the lung. At or around birth, a reversal in the relative levels of the two enzymes took place; two days after birth, the level of the enzyme for cyclic AMP was 2-3times higher than thos for cyclic GMP. Kinetic analysis showed that phohphodiesterases from extracts of the lung from all developmental stages of guinea pigs had the same Km (2.6 muM) for cyclic AMP and the same Km (6.6 muM) for cyclic GMP. The relative values of V, based on assays using the same amount of enzyme protein, in decreasing order, were fetus greater than neonate greater than adult. The present findings suggest that metabolism of the two cyclic nucleotides may be closely related to developmental processes of the tissues. Moreover, the actions involving cyclic GMP may be more predominent in the fetal lung and adult brain.

Stimulatory modulator of guanosine 3':5'-monophosphate-dependent protein kinase from mammalian tissues.

The crude protein kinase modulator preparations obtained from several rat tissues (aorta, brain heart, liver, lung, skeletal muscle, small intestine and testis) were separated into their stimulatory and inhibitory modulator components by Sephadex G-100 gel filtration. The isolated stimulatory modulator augmented the activity of guanosine 3':5'-monophosphate-dependent protein kinase. The isolated inhibitory modulator, on the other hand, depressed the activity of cyclic AMP-dependent protein kinase; it was without effect on the activity of cyclic GMP-dependent protein kinease. The present findings indicate that in the mammal, apparently in contrast to the arthropoda, separate proteins are responsibile for the stimulatory and the inhibitory activities of protein kinase modulator and that the two classes of cyclic nucleotide-dependent protein kinase are regulated in an opposing manner by these two types of modulators.

Stimulation by phospholipid of calcium-dependent phosphorylation of endogenous proteins from mammalian tissues.

The occurrence of endogenous substrate proteins for calcium-dependent protein kinase, augmented by either phospholipid or calmodulin, was examined in extracts of several rat tissues. Pancreas, vas deferens, adrenal and liver were found to contain substrate proteins for phospholipid-sensitive protein kinase. Under the conditions utilized, only vas deferens exhibited substrate proteins for calmodulin-sensitive protein kinase. Phosphorylation of pancreatic substrate protein for phospholipid-sensitive protein kinase was rapid and highly sensitive to Ca2+, being detectable within 15 s following exposure to Ca2+ and phosphatidylserine and at concentrations of Ca2+ as low as 0.5 muM. These findings suggest that phospholipid-sensitive protein kinase system may serve to mediate some effects of Ca2+ in a variety of mammalian cell types.

Alterations in activities of cyclic nucleotide systems and in beta-adrenergic receptor-mediated activation of cyclic AMP-dependent protein kinase during progression and regression of isoproterenol-induced cardiac hypertrophy.

Initial and transient increases in the basal levels of cyclic GMP in the heart were noted prior to cardiac hypertrophy in rats administered isoproterenol. Increased levels of cyclic AMP-phosphodiesterase (in both the soluble and particulate fractions) and stimulatory modulator of cyclic GMP-dependent protein kinase, however, were associated with the progression, or the state, of cardiomegaly, with their levels returning to the control values upon regression of the hypertrophy. The levels of cyclic GMP phosphodiesterase in the soluble fraction were lower, whereas those in the particulate fraction were higher, in the hypertrophied heart than the control. In cardiac hypertrophy, the maximal activity ratio(--cyclic AMP/+cyclic AMP) of cyclic AMP-dependent protein kinase in the incubated minced heart caused by isoproterenol was lower, whereas the concentration of isoproterenol required to increase the activity ratio half-maximally was higher than controls; the reduced responsiveness to the drug, however, was reversed when the hypertrophy regressed. These observations, taken collectively, appear to suggest that the desensitization of the beta-adrenergic mechanism seen in the cardiac hypertrophy produced by repeated administration of isoproterenol is associated with adaptive modifications in certain parameters of the cyclic nucleotide systems.

N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide(W-7), a calmodulin antagonist, also inhibits phospholipid-sensitive calcium-dependent protein kinase.

N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide(W-7), commonly regarded as a calmodulin antagonist, inhibited phospholipid-sensitive Ca2+ -dependent protein kinase and to a lesser extent cyclic GMP- and cyclic AMP-dependent protein kinases. Kinetic studies of the inhibition of the homogeneous spleen phospholipid-sensitive Ca2+ -dependent protein kinase indicated that W-7 inhibited the enzyme activity competitively with respect to phospholipid (Ki = 60 microM). N-(6-Aminohexyl)-1-naphthalenesulfonamide (W-5) was found to be much less potent than W-7. The findings indicate that W-7 was able to inhibit a variety of protein kinases, in addition to those requiring calmodulin previously reported.

Differential regulation of calcium-dependent and calcium-independent cyclic nucleotide phosphodiesterases from heart by palmitoylcarnitine and palmitoyl coenzyme A.

Regulation of Ca2+-dependent (peak I) and Ca2+-independent (peak II) phosphodiesterases from the heart by various fatty acyl esters and phospholipids were studied. DL-Palmitoylcarnitine stimulated the basal activity (in the absence of Ca2+) of peak I enzyme, while non-competitively inhibiting peak II enzyme with respect to cyclic AMP. It had no effect on other species of Ca2+-independent phosphodiesterases, including cyclic AMP- and cyclic GMP-specific enzymes from the lung, and cyclic CMP enzyme from the liver Palmitoyl-CoA and phosphatidylserine also stimulated the basal activity of peak I enzyme, but they were without effect on peak II enzyme. In comparison, DL-palmitoylcarnitine inhibited Ca2+-dependent activity of cardiac myosin light chain kinase, whereas phosphatidylserine was without effect. It is conceivable that differential regulation of phosphodiesterases by these lipids could profoundly alter the levels or effects, or both, of cyclic nucleotides and Ca2+ in the myocardium.

Modified cyclic nucleotide systems in Morris hepatoma 3924A favoring expression of cyclic GMP effect.

Modifications in the cyclic nucleotide systems favoring the expression of cyclic GMP effects were found to occur in the transplanted fast-growing Morris hepatoma 3924A. These included: (a) a decreased level of cyclic GMP phosphodiesterase and an increased level of cyclic AMP phosphodiesterase; (b) a disproportionately increased level of cylic GMP-dependent protein kinase relative to that of cyclic AMP-dependent protein kinase; (c) a disproportionately increased level of stimulatory modulator of cyclic AMP-dependent protein kinase relative to that of inhibitory modulator of cyclic AMP-dependent protein kinase; and (d) an increased level of phosphoprotein phosphatase.

Cyclic GMP-dependent and cyclic AMP-dependent protein kinases, protein kinase modulators and phosphodiesterases in arteries and veins of dogs. Distribution and effects of arteriovenous fistula and arterial occlusion.

Possible involvement of cyclic GMP-dependent and cyclic AMP-dependent protein kinases, protein kinase modulators and cyclic nucleotide phosphodiesterases in functions of vascular tissues were investigated in the dog. All of the above activities, localized in the smooth muscle-rich inner layer of the blood vessels, were found to be higher in the arteries than in the veins. The peripheral arteries were disproportionately richer in cyclic GMP-dependent protein kinase (as indicated by high ratios of cyclic GMP-dependent to cyclic AMP-dependent protein kinase) than were the veins, with the exception of the pulmonary artery, an atypical arterial tissue exposed to low blood pressure. Interestingly, the protein kinase ratio for the aorta, an artery with no significant role in blood pressure regulation, was not higher than that for the vena cava. Creation of femoral arteriovenous fistulae in the dogs led to preferential reductions in the cyclic GMP-dependent enzyme activity both in the proximal and distal arteries, whereas it was elevated in the stressed vein distal to the anastomotic site. The cyclic GMP-dependent enzyme was preferentially reduced in the saphenous artery distal to occlusion. Changes in the cyclic GMP-dependent enzyme activity appeared to precede gross atrophy or hypertrophy of the vessels. It is suggested that the vascular cyclic GMP-dependent protein kinase may be closely related to peripheral resistance and its regulation.

Thyroxine-induced changes in characteristics and activities of beta-adrenergic receptors and adenosine 3',5'-monophosphate and guanosine 3',5'-monophosphate systems in the heart may be related to reputed catecholamine supersensitivity in hyperthyroidism.

Modifications in characteristics and activities of beta-adrenergic receptors and certain parameters of the cyclic nucleotide systems were observed in the hypertrophied heart of the rat chronically treated with T4. These include: 1) an increased number of beta-adrenergic receptors without a change in their affinity, as determined by binding of (-)-[3H]dihydroalprenolol to the membrane; 2) increased sensitivity and magnitude of stimulation of adenylate cyclase in homogenates by isoproterenol, without a change in the basal or NaF-stimulated (total) enzyme activity; 3) decreased formation of cAMP and decreased activation of cAMP-dependent protein kinase in the minced heart stimulated by isoproterenol, probably due to decreased myocardial ATP concentration; 4) decreased activity of cAMP phosphodiesterase in the particulate fraction; 5) decreased activity of cGMP-dependent protein kinase in both the soluble and particulate fractions, accompanied by decreased activity of cAMP-dependent protein kinase in the particulate fraction; 6) decreased activity of the stimulatory modulator of cGMP-dependent protein kinase and, conversely, increased activity of the inhibitory modulator of cAMP-dependent protein kinase; and 7) increased sensitivity accompanied by decreased maximum tension development of the ventricular strip to contract in response to isoproterenol. These alterations largely disappeared upon regression of the hyperthyroid state. It is suggested that the above changes, many of which were the opposite of those reported earlier for the desensitized and hypertrophied rat heart caused by isoproterenol, may in part consitute the molecular basis for the reputed catecholamine supersensitivity of the heart in the hyperthyroid state.

beta-Adrenoceptor-adenosine 3',5-monophosphate system in human leucocytes before and after treatment for hyperthyroidism.

Modifications in characteristics of the beta-adrenoceptor-cAMP system were observed in leucocytes from 10 patients in the hyperthyroid state after antithyroid treatment. These include 1) an increased number of beta-adrenoceptors without a change in their affinity, 2) an increased magnitude of stimulation of adenylate cyclase by isoprenaline, without a change in the NaF-stimulated enzyme activity, 3) an increased cAMP-dependent protein kinase activity ratio, and 4) an increased activity of cAMP-phosphodiesterase. Moreover, the plasma cAMP levels were markedly elevated during the hyperthyroid state. It is suggested that the above changes may in part constitute the molecular basis for the reputed catecholamine supersensitivity in the hyperthyroid state.