The necessity of removal of third molars involved in mandibular fractures: A retrospective study.

This retrospective analysis aimed to investigate the necessity of removing the wisdom tooth in cases of angle fractures of the mandible. The study retrieved 595 mandible fractures from January 2006 to December 2021 through the Hospital Inpatient Enquiry System, of which 303 involved a fracture through the angle of the mandible, including the wisdom tooth socket. Of these, 203 (66.9%) underwent open reduction and internal fixation with retention of the third molar. The authors found that only four (2%) patients returned for the removal of plates and the retained third molar during the follow-up period. Therefore, the authors concluded that wisdom teeth removal should remain an exception during open reduction and internal fixation of mandibular angle fractures unless they hinder fracture reduction, pose a potential infection risk, or interfere with occlusal stability.

Cenozoic evolution of deep ocean temperature from clumped isotope thermometry.

Characterizing past climate states is crucial for understanding the future consequences of ongoing greenhouse gas emissions. Here, we revisit the benchmark time series for deep ocean temperature across the past 65 million years using clumped isotope thermometry. Our temperature estimates from the deep Atlantic Ocean are overall much warmer compared with oxygen isotope-based reconstructions, highlighting the likely influence of changes in deep ocean pH and/or seawater oxygen isotope composition on classical oxygen isotope records of the Cenozoic. In addition, our data reveal previously unrecognized large swings in deep ocean temperature during early Eocene acute greenhouse warmth. Our results call for a reassessment of the Cenozoic history of ocean temperatures to achieve a more accurate understanding of the nature of climatic responses to tectonic events and variable greenhouse forcing.

Adaptive ecological niche migration does not negate extinction susceptibility.

Extinction rates in the modern world are currently at their highest in 66 million years and are likely to increase with projections of future climate change. Our knowledge of modern-day extinction risk is largely limited to decadal-centennial terrestrial records, while data from the marine realm is typically applied to high-order (> 1 million year) timescales. At present, it is unclear whether fossil organisms with common ancestry and ecological niche exhibit consistent indicators of ecological stress prior to extinction. The marine microfossil record, specifically that of the planktonic foraminifera, allows for high-resolution analyses of large numbers of fossil individuals with incredibly well-established ecological and phylogenetic history. Here, analysis of the isochronous extinction of two members of the planktonic foraminiferal genus Dentoglobigerina shows disruptive selection differentially compounded by permanent ecological niche migration, "pre-extinction gigantism", and photosymbiont bleaching prior to extinction. Despite shared ecological and phylogenetic affinity, and timing of extinction, the marked discrepancies observed within the pre-extinction phenotypic responses are species-specific. These behaviours may provide insights into the nature of evolution and extinction in the open ocean and can potentially assist in the recognition and understanding of marine extinction risk in response to global climate change.

Proxy evidence for state-dependence of climate sensitivity in the Eocene greenhouse.

Despite recent advances, the link between the evolution of atmospheric CO2 and climate during the Eocene greenhouse remains uncertain. In particular, modelling studies suggest that in order to achieve the global warmth that characterised the early Eocene, warmer climates must be more sensitive to CO2 forcing than colder climates. Here, we test this assertion in the geological record by combining a new high-resolution boron isotope-based CO2 record with novel estimates of Global Mean Temperature. We find that Equilibrium Climate Sensitivity (ECS) was indeed higher during the warmest intervals of the Eocene, agreeing well with recent model simulations, and declined through the Eocene as global climate cooled. These observations indicate that the canonical IPCC range of ECS (1.5 to 4.5 °C per doubling) is unlikely to be appropriate for high-CO2 warm climates of the past, and the state dependency of ECS may play an increasingly important role in determining the state of future climate as the Earth continues to warm.

Differential engagement of polar networks in the glucagon-like peptide 1 receptor by endogenous variants of the glucagon-like peptide 1.

The glucagon-like peptide 1 receptor (GLP-1R) can be activated by a number of endogenous peptide hormones, including extended, processed, glycine extended and carboxy-terminally amidated versions of glucagon-like peptide 1 (GLP-1). While the main focus of the literature has been on the processed, amidated form, GLP-1(7-36)NH2, the other forms of this peptide are likely to be secreted in physiologically relevant amounts under certain circumstances. This study builds on our existing work examining the effect of mutation of conserved transmembrane polar residues within the receptor to understand the nature of binding and pleiotropic signaling in response to these alternatively processed versions of this important incretin hormone. We show that extended and processed peptides differ not only in their binding to the receptor but also in the way the receptor is engaged for activation that leads to differential signaling bias exhibited by these peptides.

Aggressive Recurrence of Oral Squamous Cell Carcinoma in a patient with Fanconi's Anaemia (FA).

Fanconi's Anaemia is a rare autosomal recessive disease for which the incidence of head and neck cancer can be increased 700-fold1. We report a case of a 31-year old Caucasian male with FA who initially presented in July 2007 with oral squamous cell carcinoma for which he received radical surgery and radiotherapy. He was disease-free until August 2015 when he presented with an extremely aggressive recurrence.

Plio-Pleistocene climate sensitivity evaluated using high-resolution CO2 records.

Theory and climate modelling suggest that the sensitivity of Earth's climate to changes in radiative forcing could depend on the background climate. However, palaeoclimate data have thus far been insufficient to provide a conclusive test of this prediction. Here we present atmospheric carbon dioxide (CO2) reconstructions based on multi-site boron-isotope records from the late Pliocene epoch (3.3 to 2.3 million years ago). We find that Earth's climate sensitivity to CO2-based radiative forcing (Earth system sensitivity) was half as strong during the warm Pliocene as during the cold late Pleistocene epoch (0.8 to 0.01 million years ago). We attribute this difference to the radiative impacts of continental ice-volume changes (the ice-albedo feedback) during the late Pleistocene, because equilibrium climate sensitivity is identical for the two intervals when we account for such impacts using sea-level reconstructions. We conclude that, on a global scale, no unexpected climate feedbacks operated during the warm Pliocene, and that predictions of equilibrium climate sensitivity (excluding long-term ice-albedo feedbacks) for our Pliocene-like future (with CO2 levels up to maximum Pliocene levels of 450 parts per million) are well described by the currently accepted range of an increase of 1.5 K to 4.5 K per doubling of CO2.

Biased allosteric modulation at the CaS receptor engendered by structurally diverse calcimimetics.

BACKGROUND AND PURPOSE: Clinical use of cinacalcet in hyperparathyroidism is complicated by its tendency to induce hypocalcaemia, arising partly from activation of calcium-sensing receptors (CaS receptors) in the thyroid and stimulation of calcitonin release. CaS receptor allosteric modulators that selectively bias signalling towards pathways that mediate desired effects [e.g. parathyroid hormone (PTH) suppression] rather than those mediating undesirable effects (e.g. elevated serum calcitonin), may offer better therapies. EXPERIMENTAL APPROACH: We characterized the ligand-biased profile of novel calcimimetics in HEK293 cells stably expressing human CaS receptors, by monitoring intracellular calcium (Ca(2+) i ) mobilization, inositol phosphate (IP)1 accumulation, ERK1/2 phosphorylation (pERK1/2) and receptor expression. KEY RESULTS: Phenylalkylamine calcimimetics were biased towards allosteric modulation of Ca(2+) i mobilization and IP1 accumulation. S,R-calcimimetic B was biased only towards IP1 accumulation. R,R-calcimimetic B and AC-265347 were biased towards IP1 accumulation and pERK1/2. Nor-calcimimetic B was unbiased. In contrast to phenylalkylamines and calcimimetic B analogues, AC-265347 did not promote trafficking of a loss-of-expression, naturally occurring, CaS receptor mutation (G(670) E). CONCLUSIONS AND IMPLICATIONS: The ability of R,R-calcimimetic B and AC-265347 to bias signalling towards pERK1/2 and IP1 accumulation may explain their suppression of PTH levels in vivo at concentrations that have no effect on serum calcitonin levels. The demonstration that AC-265347 promotes CaS receptor receptor signalling, but not trafficking reveals a novel profile of ligand-biased modulation at CaS receptors The identification of allosteric modulators that bias CaS receptor signalling towards distinct intracellular pathways provides an opportunity to develop desirable biased signalling profiles in vivo for mediating selective physiological responses.

Engendering biased signalling from the calcium-sensing receptor for the pharmacotherapy of diverse disorders.

The human calcium-sensing receptor (CaSR) is widely expressed in the body, where its activity is regulated by multiple orthosteric and endogenous allosteric ligands. Each ligand stabilizes a unique subset of conformational states, which enables the CaSR to couple to distinct intracellular signalling pathways depending on the extracellular milieu in which it is bathed. Differential signalling arising from distinct receptor conformations favoured by each ligand is referred to as biased signalling. The outcome of CaSR activation also depends on the cell type in which it is expressed. Thus, the same ligand may activate diverse pathways in distinct cell types. Given that the CaSR is implicated in numerous physiological and pathophysiological processes, it is an ideal target for biased ligands that could be rationally designed to selectively regulate desired signalling pathways in preferred cell types.

Structural and functional insights into the juxtamembranous amino-terminal tail and extracellular loop regions of class B GPCRs.

Class B guanine nucleotide-binding protein GPCRs share heptahelical topology and signalling via coupling with heterotrimeric G proteins typical of the entire superfamily of GPCRs. However, they also exhibit substantial structural differences from the more extensively studied class A GPCRs. Even their helical bundle region, most conserved across the superfamily, is predicted to differ from that of class A GPCRs. Much is now known about the conserved structure of the amino-terminal domain of class B GPCRs, coming from isolated NMR and crystal structures, but the orientation of that domain relative to the helical bundle is unknown, and even less is understood about the conformations of the juxtamembranous amino-terminal tail or of the extracellular loops linking the transmembrane segments. We now review what is known about the structure and function of these regions of class B GPCRs. This comes from indirect analysis of structure-function relationships elucidated by mutagenesis and/or ligand modification and from the more direct analysis of spatial approximation coming from photoaffinity labelling and cysteine trapping studies. Also reviewed are the limited studies of structure of some of these regions. No dominant theme was recognized for the structures or functional roles of distinct regions of these juxtamembranous portions of the class B GPCRs. Therefore, it is likely that a variety of molecular strategies can be engaged for docking of agonist ligands and for initiation of conformational changes in these receptors that would be expected to converge to a common molecular mechanism for activation of intracellular signalling cascades.

The class B G-protein-coupled GLP-1 receptor: an important target for the treatment of type-2 diabetes mellitus.

Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone secreted from L cells in the distal small intestine and proximal colon after a meal that acts as an incretin to augment the insulin response, while also inhibiting glucagon and slowing gastric emptying. These characteristics of GLP-1, as well as its ability to reduce islet beta cell apoptosis and expand beta cell mass and its cardioprotective and neuroprotective effects, provide a broad spectrum of actions potentially useful for the management of type-2 diabetes mellitus. GLP-1 also has the added advantage of having its incretin effects dependent on the level of serum glucose, only acting in the presence of hyperglycaemia, and thereby preventing hypoglycemic responses. Although natural GLP-1 has a very short half-life, limiting its therapeutic usefulness, a variety of analogues and formulations have been developed to provide extended actions and to limit side effects. However, all of these peptides require parenteral administration. Potentially orally active small-molecule agonists acting at the GLP-1 receptor are also being developed, but have not yet been approved for clinical use. Recent insights into the molecular nature of the class B G-protein-coupled GLP-1 receptor has provided insights into the modes of binding these types of ligands, as well as providing opportunities for rational enhancement. The advantages and disadvantages of each of these agents and their possible clinical utility will be explored.

Optimal patient positioning for ligamentotaxis during balloon kyphoplasty of the thoracolumbar and lumbar spine.

Percutaneous balloon kyphoplasty aims to restore vertebral height, correct angular deformity and stabilize the spine in the setting of vertebral compression fractures. The patient is positioned prone with supports under the iliac crests and upper thorax to allow gravity to extend the spine. In the treatment of lumbar fractures, we evaluated patient positioning with the contribution of hip extension to increase anterior ligamentotaxis, thus facilitating restoration of vertebral height. Our positioning technique created a mean anterior height increase from 72% to 78% of the average height of the cranial and caudal vertebrae (p=0.037). Balloon inflation did not significantly further increase anterior or posterior vertebral height, or Cobb angle.

Susceptibility to nontuberculous mycobacterial lung disease.

The nontuberculous mycobacteria (NTM) exhibit heterogeneous pathogenicity in humans. Articles on known and potential human factors capable of producing susceptibility to NTM lung disease (NTMLD) were identified by a systematic search of the medical literature, and are reviewed in the present study. Patients with pre-existing structural lung disease are known to be at risk of NTMLD. Other susceptible groups have become recognised since the 1980s, in particular middle-aged nonsmokers without previous lung disease (a group including those with Lady Windermere syndrome) and patients with genetically determined defects of cell-mediated immunity, including abnormalities of the interleukin-12/interferon-gamma axis, certain human leukocyte antigen alleles, cystic fibrosis transmembrane conductance regulator mutations, and polymorphisms of solute carrier 11A1 (or natural resistance-associated macrophage protein 1) and the vitamin D receptor. Information is also accruing about acquired systemic causes of susceptibility to NTMLD, including inhibitory antibodies directed against interferon-gamma, post-menopausal waning of endogenous oestrogen levels, coeliac disease and exposure to use of dietary phyto-oestrogens. It is not known whether immunosuppressive factors, such as oral corticosteroid treatment, chronic renal failure, diabetes mellitus and other known risk factors for pulmonary tuberculosis, are also risk factors for the development of NTMLD. Caution is appropriate in managing such patients.

Involvement of the sigma1 (sigma1) receptor in the anti-amnesic, but not antidepressant-like, effects of the aminotetrahydrofuran derivative ANAVEX1-41.

BACKGROUND AND PURPOSE: Tetrahydro-N, N-dimethyl-5, 5-diphenyl-3-furanmethanamine hydrochloride (ANAVEX1-41) is a potent muscarinic and sigma(1) (sigma (1)) receptor ligand. The sigma (1) receptor modulates glutamatergic and cholinergic responses in the forebrain and selective agonists are potent anti-amnesic and antidepressant DRUGS. WE HAVE HERE ANALYSED THE SIGMA (1) COMPONENT IN THE BEHAVIOURAL EFFECTS OF ANAVEX1-41. EXPERIMENTAL APPROACH: Binding of ANAVEX1-41 to muscarinic and sigma (1) receptors were measured using cell membranes. Behavioural effects of ANAVEX1-41 were tested in mice using memory (spontaneous alternation, passive avoidance, water-maze) and antidepressant-like activity (forced swimming) procedures. KEY RESULTS: In vitro, ANAVEX1-41 was a potent muscarinic (M(1)>M(3), M(4)>M(2) with K(i) ranging from 18 to 114 nM) and selective sigma (1) ligand (sigma (1), K(i)=44 nM; sigma (2), K(i)=4 microM). In mice, ANAVEX1-41 failed to affect learning when injected alone (0.03-1 mg kg(-1)), but attenuated scopolamine-induced amnesia with a bell-shaped dose response (maximum at 0.1 mg kg(-1)). The sigma (1) antagonist BD1047 blocked the anti-amnesic effect of ANAVEX1-41 on both short- and long-term memories. Pretreatment with a sigma (1) receptor-directed antisense oligodeoxynucleotide prevented effects of ANAVEX1-41 only in the passive avoidance procedure, measuring long-term memory. ANAVEX1-41 reduced behavioural despair at 30 and 60 mg kg(-1), without involving the sigma (1) receptor, as it was not blocked by BD1047 or the antisense oligodeoxynucleotide. CONCLUSIONS AND IMPLICATIONS: ANAVEX1-41 is a potent anti-amnesic drug, acting through muscarinic and sigma (1) receptors. The latter component may be involved in the enhancing effects of the drug on long-term memory processes.

Discovery of antiandrogen activity of nonsteroidal scaffolds of marketed drugs.

Finding good drug leads de novo from large chemical libraries, real or virtual, is not an easy task. High-throughput screening is often plagued by low hit rates and many leads that are toxic or exhibit poor bioavailability. Exploiting the secondary activity of marketed drugs, on the other hand, may help in generating drug leads that can be optimized for the observed side-effect target, while maintaining acceptable bioavailability and toxicity profiles. Here, we describe an efficient computational methodology to discover leads to a protein target from safe marketed drugs. We applied an in silico "drug repurposing" procedure for identification of nonsteroidal antagonists against the human androgen receptor (AR), using multiple predicted models of an antagonist-bound receptor. The library of marketed oral drugs was then docked into the best-performing models, and the 11 selected compounds with the highest docking score were tested in vitro for AR binding and antagonism of dihydrotestosterone-induced AR transactivation. The phenothiazine derivatives acetophenazine, fluphenazine, and periciazine, used clinically as antipsychotic drugs, were identified as weak AR antagonists. This in vitro biological activity correlated well with endocrine side effects observed in individuals taking these medications. Further computational optimization of phenothiazines, combined with in vitro screening, led to the identification of a nonsteroidal antiandrogen with improved AR antagonism and marked reduction in affinity for dopaminergic and serotonergic receptors that are the primary target of phenothiazine antipsychotics.

Relaxin receptors--new drug targets for multiple disease states.

Relaxin was discovered more than 75 years prior to the identification of the receptors that mediate its actions. There has been a slow emergence in understanding the role of relaxin, with it being denoted initially as a hormone of pregnancy due to its observed effects to relax pubic ligaments and soften the cervix of guinea pigs to facilitate parturition. However, many other physiological roles have been identified for relaxin, including cardiovascular and neuropeptide functions and an ability to induce the matrix metalloproteinases, so it is clear that relaxin is not exclusively a hormone of pregnancy but has a much wider role in vivo. The recent de-orphanisation of four receptors LGR7, LGR8, GPCR135 (SALPR) and GPCR142 (GPR100) that respond to and bind at least one of the three forms of relaxin identified to date, allows dissection of this system to determine the precise role of each receptor and enable the identification of new targets for treatment of numerous disease states. Relaxin has the potential to be useful for the treatment of scleroderma, fibrosis, in orthodontics and to facilitate embryo implantation in humans. Relaxin antagonists may act as contraceptives or prevent the development of breast cancer metastases. Recent research has added considerable knowledge to the signalling pathways activated by relaxin, which will aid our understanding of how relaxin produces its effects. The focus of this review is to bring together recent developments in the relaxin receptor field and to highlight their potential as drug targets.

Amylin receptors: molecular composition and pharmacology.

Several receptors which bind the hormone AMY (amylin) with high affinity have now been identified. The minimum binding unit is composed of the CT (calcitonin) receptor at its core, plus a RAMP (receptor activity modifying protein). The receptors have been named AMY(1(a)), AMY(2(a)) and AMY(3(a)) in accordance with the association of the CT receptor (CT((a))) with RAMP1, RAMP2 and RAMP3 respectively. The challenge is now to determine the localization and pharmacological nature of each of these receptors. Recent attempts to achieve these aims will be briefly discussed.

G-protein-coupled receptor allosterism: the promise and the problem(s).

Allosteric modulators of G-protein-coupled receptors interact with binding sites that are topographically distinct from the orthosteric site recognized by the receptor's endogenous agonist. Allosteric ligands offer a number of advantages over orthosteric drugs, including the potential for greater receptor subtype selectivity and a more 'physiological' regulation of receptor activity. However, the manifestations of allosterism at G-protein-coupled receptors are quite varied, and significant challenges remain for the optimization of screening methods to ensure the routine detection and validation of allosteric ligands.

Allosteric modulation of G protein-coupled receptors.

G protein-coupled receptors (GPCRs) constitute the largest receptor superfamily in the human genome and represent the most common targets of drug action. Classic agonist and antagonist ligands that act at GPCRs tend to bind to the receptor's orthosteric site, that is, the site recognized by the endogenous agonist for that receptor. However, it is now evident that GPCRs possess additional, extracellular, allosteric binding sites that can be recognized by a variety of small molecule modulator ligands. Allosteric modulators offer many advantages over classic orthosteric ligands as therapeutic agents, including the potential for greater GPCR-subtype selectivity and safety. However, the manifestations of allosterism at GPCRs are many and varied and, in the past, traditional screening methods have generally failed to detect many allosteric modulators. More recently, there have been a number of major advances in high throughput screening, including the advent of cell-based functional assays, which have led to the discovery of more allosteric modulator ligands than previously appreciated. In addition, a number of powerful analytical techniques have also been developed exclusively for detecting and quantifying allosteric effects, based on an increased awareness of various mechanisms underlying allosteric modulator actions at GPCRs. Together, these advances promise to change the current paucity of GPCR allosteric modulators in the clinical setting and yield novel therapeutic entities for the treatment of numerous disorders.