Evaluation of a pharmacist-managed amiodarone monitoring program.

Background: Because of the potential for serious adverse effects, patients treated with amiodarone must be carefully screened and routinely monitored for potential liver, thyroid, and pulmonary toxicity. However, laboratory and pulmonary monitoring rates have been found to be substantially lower than recommended in guidelines, including those of the North American Society of Pacing and Electrophysiology (NASPE, 2007).

Objective: To (a) assess rates of laboratory monitoring of liver, thyroid, and pulmonary function and adverse events in a pharmacist-managed amiodarone monitoring program compared with usual care in an integrated health care system and (b) estimate return on investment (ROI) from this intervention.

Anabolic and antiresorptive drugs improve trabecular microarchitecture and reduce fracture risk following radiation therapy.

Many patients with symptomatic bone metastases receive radiation therapy, even though radiation is known to have potential adverse effects on bone. We hypothesized that the concurrent use of a bisphosphonate drug (zoledronic acid, ZA) or a combination of ZA plus an anabolic agent (parathyroid hormone, PTH) would lead to improvements in the microarchitecture and mechanical properties of irradiated bone. Human breast cancer cells were injected into the distal femur of 56 female nude mice, which were then divided into four groups: no treatment (0 Gy), radiation administered 4 weeks postinjection (20 Gy), radiation plus ZA (12.

C-terminal analogues of parathyroid hormone: effect of C-terminus function on helical structure, stability, and bioactivity.

We have studied the effects of C-terminal group modifications (amide, methylamide, dimethylamide, aldehyde, and alcohol) on the conformation, adenylyl cyclase stimulation (AC), or binding of parathyroid hormone (hPTH) analogues, hPTH(1-28)NH(2) and hPTH(1-31)NH(2). hPTH(1-31)NH(2) has a C-terminal alpha-helix bounded by residues 17-29 [Chen, Z., et al.

Role of amino acid side chains in region 17-31 of parathyroid hormone (PTH) in binding to the PTH receptor.

The principal receptor-binding domain (Ser(17)-Val(31)) of parathyroid hormone (PTH) is predicted to form an amphiphilic alpha-helix and to interact primarily with the N-terminal extracellular domain (N domain) of the PTH receptor (PTHR). We explored these hypotheses by introducing a variety of substitutions in region 17-31 of PTH-(1-31) and assessing, via competition assays, their effects on binding to the wild-type PTHR and to PTHR-delNt, which lacks most of the N domain. Substitutions at Arg(20) reduced affinity for the intact PTHR by 200-fold or more, but altered affinity for PTHR-delNt by 4-fold or less.

Backbone-methylated analogues of the principle receptor binding region of human parathyroid hormone. Evidence for binding to both the N-terminal extracellular domain and extracellular loop region.

We have used backbone N-methylations of parathyroid hormone (PTH) to study the role of these NH groups in the C-terminal amphiphilic alpha-helix of PTH (1-31) in binding to and activating the PTH receptor (P1R). The circular dichroism (CD) spectra indicated the structure of the C-terminal alpha-helix was locally disrupted around the methylation site. The CD spectra differences were explained by assuming a helix disruption for four residues on each side of the site of methylation and taking into account the known dependence of CD on the length of an alpha-helix.

Parathyroid hormone, its fragments and their analogs for the treatment of osteoporosis.

The susceptibility to traumatic fracturing of osteopenic bones, and the spontaneous fracturing of osteoporotic bones by normal body movements caused by the microstructural deterioration and loss of bone, are currently treated with antiresorptive drugs, such as the bisphosphonates, calcitonin, estrogens, and selective estrogen receptor modulators. These antiresorptive agents target osteoclasts and, as their name indicates, reduce or stop bone resorption. They cannot directly stimulate bone formation, increase bone mass above normal values in ovariectomized rat models, or improve microstructure.

Constrained analogs of osteogenic peptides.

Osteogenic peptides are, or have potential to be, therapies for the treatment of osteoporosis, fracture repair, and repair of loosened bone implants. Human parathyroid hormone has been approved for the treatment of post-menopausal osteoporosis. Constrained analogs of PTH and the parathyroid-hormone related peptide (PTHrP) have aided the understanding of how PTH and PTHrP bind to their common receptor and some of these analogs have improved properties that make them possible candidates for clinical trial.

Treatment with parathyroid hormone hPTH(1-34), hPTH(1-31), and monocyclic hPTH(1-31) enhances fracture strength and callus amount after withdrawal fracture strength and callus mechanical quality continue to increase.

The influence of intermittent hPTH(1-34)NH2, hPTH(1-31)NH2, and monocyclic [Leu27]cyclo (Glu22-Lys26)hPTH(1-31)NH2 treatment on callus formation, mechanical strength, and callus tissue mechanical quality of tibial fractures in rats was investigated after 8 and 16 weeks of healing. In the 8 weeks of healing animals, the PTH-peptides were injected subcutaneously during the entire observation period (15 nmol/kg/day [hPTH(1-34)NH2: 15 nmol = 60 microg]), and control animals with fractures were given vehicle. In the 16 weeks of healing animals, the PTH-peptides were injected only during the first 8 weeks of healing (15 nmol/kg/day), after which the animals were left untreated during the rest of the healing period.

Ligand-selective dissociation of activation and internalization of the parathyroid hormone (PTH) receptor: conditional efficacy of PTH peptide fragments.

G protein-coupled receptors (GPCRs) mediate the action of many hormones, cytokines, and sensory and chemical signals. It is generally thought that receptor desensitization and internalization require occupancy and activation of the GPCR. PTH and PTHrP receptor (PTH1R) belongs to GPCR class B and is the major regulator of extracellular calcium homeostasis.

The effects of parathyroid hormone fragments on bone formation and their lack of effects on the initiation of colon carcinogenesis in rats as indicated by preneoplastic aberrant crypt formation.

The parathyroid hormone (PTH) and some of its fragments and analogs stimulate bone growth in various animal models and humans and one of them (hPTH-(1-34)) has been approved by the USFDA for treating osteoporosis. However, there are reports that PTH can stimulate the PI-3 kinase/mitogen-activated protein kinases-mediated proliferation of rat enterocytes and that primary hyperparathyroidism in humans is associated with an increased incidence of colon cancer. Here we have investigated the ability of two PTH fragments, hPTH-(1-34)NH(2) and [Leu(27)]cyclo(Glu(22)-Lys(26))hPTH-(1-31)NH(2) to initiate colon carcinogenesis or increase the initiatory activity of the widely used colon carcinogen azoxymethane (AOM).

Bone growth stimulators. New tools for treating bone loss and mending fractures.

In the new millennium, humans will be traveling to Mars and eventually beyond with skeletons that respond to microgravity by self-destructing. Meanwhile in Earth's aging populations growing numbers of men and many more women are suffering from crippling bone loss. During the first decade after menopause all women suffer an accelerating loss of bone, which in some of them is severe enough to result in "spontaneous" crushing of vertebrae and fracturing of hips by ordinary body movements.

The control of bone growth by parathyroid hormone, leptin, & statins.

There is a need for anabolic drugs that can stimulate bone growth, improve bone microarchitecture, accelerate fracture healing and thus restore bone strength to oteoporotics. The anabolic agents currently leading the way to the clinic are the parathroid hormone (PTH) and some of its adenylyl cyclase-stimulating fragments. Here we discuss what is known about the genes and their products that are stimulated by PTHR1 receptor signals and in four ways cause a large accumulation of bone-building osteoblasts.

C-terminal cyclization of an SDF-1 small peptide analogue dramatically increases receptor affinity and activation of the CXCR4 receptor.

In an effort to improve the activities and bioavailabilities of stromal cell-derived factor-1 (SDF-1, CXCL12) sdf-(1-67)-OH (1), we have prepared a linear peptide analogue [sdf-(1-31)-NH(2) (2)] and two lactam analogues [cyclo(Lys(20)-Glu(24))-sdf-(1-31)-NH(2) (3) and cyclo(Glu(24)-Lys(28))-sdf-(1-31)-NH(2) (4)], consisting of the N-terminal region (amino acids 1-14) joined by a four-glycine linker to the C-terminal region (amino acids 56-67) of 1. Analogues 2 and 4 had eight residues of alpha-helix, as estimated from its circular dichroism (CD) spectra, in contrast to 10 residues in analogue 3. Cyclization of analogue 2 at residues 20 and 24 to give analogue 3 resulted in only a slight change to the theta;(222)/theta;(209) ratio (0.

Structural requirements for conserved arginine of parathyroid hormone.

Arg-20 is one of two residues conserved in all peptides known to activate the parathyroid hormone (PTH) receptor. Previous studies have failed to find any naturally encoded analogues of residue 20 that had any adenylyl cyclase (AC) stimulating activity. In this work we have studied substitutions of Arg-20 with nonencoded amino acids and conformationally constrained analogues with side chains mimicking that of Arg.

Parathyroid hormone: an anabolic treatment for osteoporosis.

Osteoporosis is a disease characterised by low bone mass, structural deterioration of bone and increased risk of fracture. The prevalence, and cost, of osteoporosis is increasing dramatically with our ageing population and the World Health Organization now considers it to be the second-leading healthcare problem. All currently approved therapies for osteoporosis (eg.

Immunization of mice with lipopeptide antigens encapsulated in novel liposomes prepared from the polar lipids of various Archaeobacteria elicits rapid and prolonged specific protective immunity against infection with the facultative intracellular pathogen, Listeria monocytogenes.

Protective immunity to intracellular bacterial pathogens usually requires the participation of specific CD8+ T cells. Natural exposure of the host to sublethal infection, or vaccination with attenuated live vaccines are the most effective means of eliciting prolonged protective cell-mediated immunity against this class of pathogens. The ability to replace these immunization strategies with defined sub-unit vaccines would represent a major advance for clinical vaccinology.

The effect of monocyclic and bicyclic analogs of human parathyroid hormone (hPTH)-(1-31)NH2 on bone formation and mechanical strength in ovariectomized rats.

The [Leu27]cyclo(Glu22-Lys26)-hPTH-(1-31)NH2 lactam is a stronger stimulator of adenylyl cyclase activity and a better stimulator of trabecular bone in the ovariectomized (OVX) rat model of osteopenia than hPTH-(1-31)NH2. This enhanced activity is due in large part to the stabilization of the amphiphilic receptor-binding alpha-helix in the Ser17-Gln29 region. The goal of the present study was to determine whether further cyclization could produce a more active hPTH analog.

Stimulation of protein kinase C activity in cells expressing human parathyroid hormone receptors by C- and N-terminally truncated fragments of parathyroid hormone 1-34.

The parathyroid hormone (PTH) fragment PTH(1-34) stimulates adenylyl cyclase, phospholipase C (PLC), and protein kinase C's (PKCs) in cells that express human, opossum, or rodent type 1 PTH/PTH-related protein (PTHrP) receptors (PTHR1s). Certain carboxyl (C)-terminally truncated fragments of PTH(1-34), such as human PTH(1-31) [hPTH-(1-31)NH2], stimulate adenylyl cyclase but not PKCs in rat osteoblasts or PLC and PKCs in mouse kidney cells. The hPTH(1-31)NH2 peptide does fully stimulate PLC in HKRK B7 porcine renal epithelial cells that express 950,000 transfected hPTHR1s per cell.

The parathyroid hormones: bone-forming agents for treatment of osteoporosis.

This is a 3-part article. Part 1 is an overview of bone formation and resorption and the consequences of estrogen loss on bone. Part 2 comprehensively reviews the most current data on the ability of a family of potent osteoblast-stimulating bone-builders, the native 84-amino-acid parathyroid hormone (PTH), and certain of its 31- to 38- amino-acid fragments to stimulate the growth of animal and human bones.

Structure and activities of constrained analogues of human parathyroid hormone and parathyroid hormone-related peptide: implications for receptor-activating conformations of the hormones.

Parathyroid hormone (PTH) has a helix-bend-helix structure in solution. Part of the C-terminal helix, residues 21-31, is amphiphilic and forms a critical receptor-binding region. Stabilization of this alpha-helix by lactam formation between residues spaced i, i + 4 on the polar face was previously reported to increase adenylyl cyclase-stimulating (AC) activity if between residues 22 and 26 but to diminish it if between residues 26 and 30 [Barbier et al.

The parathyroid hormone, its fragments and analogues--potent bone-builders for treating osteoporosis.

As populations age a rising number of men and women, but especially women during the first decade after menopause, become victims of a severe, accelerated loss of bone with crippling fractures known as osteoporosis. This often results in costly, prolonged hospitalisation and perhaps indirectly, death. Osteoporosis in women is caused by the menopausal oestrogen decline, which removes several key restraints on the generation, longevity and activity of bone-resorbing osteoclasts.

Solution structure of the osteogenic 1-31 fragment of the human parathyroid hormone.

The solution conformations of a selectively osteogenic 1-31 fragment of the human parathyroid hormone (hPTH), hPTH(1-31)NH(2), have been characterized by use of very high field NMR spectroscopy at 800 MHz. The combination of the CalphaH proton and (13)Calpha chemical shifts, (3)J(NH)(alpha) coupling constants, NH proton temperature coefficients, and backbone NOEs reveals that the hPTH(1-31)NH(2) peptide has well-formed helical structures localized in two distinct segments of the polypeptide backbone. There are also many characteristic NOEs defining specific side-chain/backbone and side-chain/side-chain contacts within both helical structures.