Under the spotlight: understanding the role of the Chief Medical Officer in a pandemic

As the COVID-19 pandemic took hold in 2020, Chief Medical Officers (CMOs) entered the public spotlight like never before. Amidst this increased visibility, the role is deeply contested. Much of the disagreement concerns whether CMOs should act independently of the government: while some argue CMOs should act as independent voices who work to shape government policy to protect public health, others stress that CMOs are civil servants whose job is to support the government. The scope and diversity of debates about the CMO role can be explained by its inherently contradictory nature, which requires incumbents to balance their commitments as physicians with their mandates as civil servants who advise and speak on the government’s behalf. The long-haul COVID-19 pandemic has further tested the CMO role and has shone light on its varying remits and expectations across different jurisdictions, institutions and contexts. It is perhaps unsurprising, then, that calls to amend the CMO role have emerged in some jurisdictions during the pandemic. However, any discussions about changing the CMO role need a stronger understanding of how different institutional and individual approaches impact what incumbents feel able to do, say and achieve. Based on an ongoing comparative analysis of the position across five countries with Westminster-style political systems, we provide an overview of the CMO role, explain its prominence in a pandemic, examine some debates surrounding the role and discuss a few unanswered empirical questions before describing our ongoing study in greater detail.

A pharmacokinetic and biomarker study of delayed-release dimethyl fumarate in subjects with secondary progressive multiple sclerosis: evaluation of cerebrospinal fluid penetration and the effects on exploratory biomarkers

BACKGROUND

Biomarkers are a useful and reliable measure of disease activity in many fields of medicine. Axonal and glial biomarkers in multiple sclerosis (MS) are being applied more often as technology is improving and becoming increasingly reliable. Nonclinical studies have shown dimethyl fumarate (DMF) to have cytoprotective and anti-inflammatory effects. The purpose of this study is to explore the pharmacokinetics (PK) of DMF (by measuring MMF, the active compound) in serum and cerebrospinal fluid (CSF) as well as relevant biomarker data for patients with secondary progressive MS (pwSPMS) and whether there is objective evidence for neuroprotection in pwSPMS treated with DMF.

METHODS

Sixteen pwSPMS had serum and cerebrospinal fluid (CSF) evaluation for PK studies levels of MMF at various time points after ingestion of DMF. The CSF biomarkers neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), ubiquitin carboxyo-terminal hydrolase isozyme L1 (UCH-L1) and total tau (T-tau) were measured at baseline, week 6 and week 28 after initiating DMF with a starting dose of 120 mg twice daily for 4 weeks, followed by a maintenance dose of 240 mg twice daily. Clinical correlation of these patients with EDSS and MRI at these same time periods were made with the biomarkers. Four normal human volunteers had CSF studies for biomarkers at baseline.

RESULTS

PK data showed CSF MMF concentration 11% of plasma with Tmax of plasma at 5 hr and Tmax of CSF at 7 hr. Biomarker data showed that CS NfL and to a lesser extent, GFAP, but not UCH-L1 nor T-tau showed relevant changes with clinical data. Some pwSPMS receiving DMF showed clinical improvements in Expanded Disability Status Scale (EDSS). Biomarker changes, but not MRI, correlated with clinical measures in this group of pwSPMS over the observation period.

CONCLUSIONS

PK data showed that the Tmax of CSF MMF peaked only 2 hours later than that of plasma with 11% measured in the CSF so that MMF readily crossed the blood brain barrier allowing potential direct penetration into the brain. NfL CSF levels, and to a lesser extent, GFAP CSF levels, showed correlation to disease activity in pwSPMS . These data suggest that DMF may have some benefit in reducing disease activity in pwSPMS if studied for a longer duration and larger well-controlled studies are warranted. DMF was reasonably well tolerated but 3 of the 16 patients did discontinue DMF at 6 weeks due to persistent side effects. NfL appeared to be more clinically relevant biomarker than brain MRI in this this group during the 28-week study period.

Hybridisation capture allows DNA damage analysis of ancient marine eukaryotes

Marine sedimentary ancient DNA (sedaDNA) is increasingly used to study past ocean ecosystems, however, studies have been severely limited by the very low amounts of DNA preserved in the subseafloor, and the lack of bioinformatic tools to authenticate sedaDNA in metagenomic data. We applied a hybridisation capture 'baits' technique to target marine eukaryote sedaDNA (specifically, phyto- and zooplankton, 'Planktonbaits1'; and harmful algal bloom taxa, 'HABbaits1'), which resulted in up to 4- and 9-fold increases, respectively, in the relative abundance of eukaryotes compared to shotgun sequencing. We further used the bioinformatic tool 'HOPS' to authenticate the sedaDNA component, establishing a new proxy to assess sedaDNA authenticity, "% eukaryote sedaDNA damage", that is positively correlated with subseafloor depth. We used this proxy to report the first-ever DNA damage profiles from a marine phytoplankton species, the ubiquitous coccolithophore Emiliania huxleyi. Our approach opens new avenues for the detailed investigation of long-term change and evolution of marine eukaryotes over geological timescales.

Phase II Dose Selection for Alpha Synuclein-Targeting Antibody Cinpanemab (BIIB054) Based on Target Protein Binding Levels in the Brain

This modeling and simulation analysis was aimed at selecting doses of cinpanemab (BIIB054), a monoclonal antibody targeting aggregated α‐synuclein, for a phase II study in Parkinson’s disease (PD). Doses and regimens were proposed based on anticipated target concentration in brain interstitial fluid (ISF); in vitro/in vivo data on the affinity of monoclonal antibodies to the target protein; and safety, tolerability, and pharmacokinetic data (1–135 mg/kg intravenous administration) from a phase I single ascending dose (SAD) study. A population pharmacokinetic modeling approach was used to select intravenous doses of 250, 1,250, and 3,500 mg every 4 weeks, to maintain 50%, 90%, and > 90% of target binding in ISF of PD participants. A favorable safety profile from the SAD study—which showed that cinpanemab was generally well‐tolerated at doses up to 90 mg/kg, supported by modeling and simulations of the anticipated safety margins—allowed implementation of a fixed‐dose approach.

Combined effects of HIV and obesity on the gastrointestinal microbiome of young men who have sex with men

OBJECTIVES

The prevalence of obesity is rising among people living with HIV, which may synergistically increase inflammation and the risk of associated diseases. Disruption of gut bacterial communities may be one of the key drivers of this inflammation; however, the combined effects of HIV and obesity on the microbiome have not been explored.

METHODS

This study included 381 men who have sex with men. Thirty-nine were HIV-positive and obese (H+O+), 143 were HIV-positive and nonobese, 64 were HIV-negative and obese, and 135 were HIV-negative and nonobese. Microbiome composition was assessed by targeted sequencing of the V4 region of the 16S ribosomal RNA (rRNA) gene using rectal swab samples. Inverse probability of treatment-weighted marginal structural models were used to investigate differences in microbial composition between groups while controlling for numerous clinical and behavioural confounders.

RESULTS

Significant variability in microbial composition was explained by the combination of HIV and obesity, over and above each condition alone (R² for the marginal contribution of the H+/O+ group = 0.008; P = 0.001). H+O+ participants had the highest ratios of Prevotella to Bacteroides, a pro-inflammatory enterotype that has been described in HIV infection and obesity independently. H+O+ participants had lower levels of Bacteroides and Veillonella than all other groups, suggesting a synergistic effect of HIV and obesity on these genera.

CONCLUSIONS

Our findings support the hypothesis that HIV and obesity act together to disrupt gut microbial communities, which may help explain higher levels of generalized inflammation among people living with both HIV and obesity.

Urogenital symptoms in mitochondrial disease: overlooked and undertreated

Background and purpose

Bowel symptoms are well documented in mitochondrial disease. However, data concerning other pelvic organs is limited. A large case–control study has therefore been undertaken to determine the presence of lower urinary tract symptoms (LUTS) and sexual dysfunction in adults with genetically confirmed mitochondrial disease.

Methods

Adults with genetically confirmed mitochondrial disease and control subjects were recruited from a specialist mitochondrial clinic. The presence and severity of LUTS and their impact on quality of life, in addition to sexual dysfunction and bowel symptoms, were captured using four validated questionnaires. Subgroup analysis was undertaken in patients harbouring the m.3243A>G MT‐TL1 mitochondrial DNA mutation. A subset of patients underwent urodynamic studies to further characterize their LUTS.

Results

Data from 58 patients and 19 controls (gender and age matched) were collected. Adults with mitochondrial disease had significantly more overactive bladder (81.5% vs. 56.3%, P = 0.039) and low stream (34.5% vs. 5.3%, P = 0.013) urinary symptoms than controls. Urodynamic studies in 10 patients confirmed that bladder storage symptoms predominate. Despite high rates of LUTS, none of the patient group was receiving treatment. Female patients and those harbouring the m.3243A>G MT‐TL1 mutation experienced significantly more sexual dysfunction than controls (53.1% vs. 11.1%, P = 0.026, and 66.7% vs. 26.3%, P = 0.011, respectively).

Conclusions

Lower urinary tract symptoms are common but undertreated in adult mitochondrial disease, and female patients and those harbouring the m.3243A>G MT‐TL1 mutation experience sexual dysfunction. Given their impact on quality of life, screening for and treating LUTS and sexual dysfunction in adults with mitochondrial disease are strongly recommended.

Landscape hydrology. The hydrological legacy of deforestation on global wetlands

Increased catchment erosion and nutrient loading are commonly recognized impacts of deforestation on global wetlands. In contrast, an increase in water availability in deforested catchments is well known in modern studies but is rarely considered when evaluating past human impacts. We used a Budyko water balance approach, a meta-analysis of global wetland response to deforestation, and paleoecological studies from Australasia to explore this issue. After complete deforestation, we demonstrated that water available to wetlands increases by up to 15% of annual precipitation. This can convert ephemeral swamps to permanent lakes or even create new wetlands. This effect is globally significant, with 9 to 12% of wetlands affected, including 20 to 40% of Ramsar wetlands, but is widely unrecognized because human impact studies rarely test for it.

Empirical Interatomic Potentials for L1O Tial and B2 Nial

Recent studies have suggested a particular relationship between the degree of covalent bonding in TiAl and the mobility of dislocation[1,2]. Ultimately such electronic effects In ordered compounds must dictate the dislocation core structures and at the same time the dislocation mobility within a given compound. However, direct modelling of line defects Is beyond the capability of todays electronic structure techniques. Alternatively, significant steps toward extending our understanding of the flow behaviour of structural intermetallics may come through general application of empirical interatomic potential methods for calculating the structure and mobility of defects. Toward this end, we have constructed semi-empirical interatomic potentials within the embedded atom formalism for L1O and B2 type structures. These potentials have been determined by fitting to known bulk structural and elastic properties of TIAl and NiAl, using least squares procedures. Simple expressions that relate the parameters of the potentials to the bulk properties are used in the fitting procedure. Calculations of dislocation core structures and planar fault energies using these potentials are considered. The differences between the optimized bulk properties predicted from the potentials and the values for these properties are discussed in terms of non-spherical nature of the electron density distribution. Empirical methods which incorporate these effects into interatomic potentials are briefly discussed.

The Interaction Between Dislocations and Lamellar Grain Boundaries in Pst γ Tiai

In lamellar TiAl the flat-plate geometry of the grains, the barriers to deformation across the grain boundaries and the coherency stresses all contribute to a marked anisotropy in the yield and fracture stresses of the material. Both yield and fracture occur at low stresses when the deformation is within the lamellae (soft mode) and they occur at high stresses when the deformation crosses the lamellae (hard mode). The anisotropy is enhanced by a new effect which can soften the soft mode and harden the hard mode: the geometry of the lamellar boundary produces degeneracies in the planar fault energies at the interfaces which enhance the mobilities of dislocations on these interfaces. These degeneracies modify the core structure of dislocations on or near the interfaces, consequently soft mode dislocations can dissociate widely and move more easily when their glide plane is contained in the interface. Hard mode dislocations can substantially reduce their core energies when intersecting a γ/γ interface, and subsequently become immobilized, by cross slipping on to the interface plane. This paper presents a discussion of the geometry and relative energies of the γ/γ interfaces using elements of Bollman O-lattice theory. In order to investigate the influence of the interfaces on dislocation core structure we have fit an empirical Embedded Atom Method (EAM) potential to the structural and elastic properties of bulk L10 TiAl. The mobility and core structure of the twinning dislocation at the 180° interface and the perfect, 1/2<110] screw dislocation at the 60° and 120° interfaces were calculated using molecular statics within the EAM. We have also studied the influence of one and two atomic step ledges on dislocation mobility in the 120° interface. We find in general that dislocations are more glissile on the γ/γ interfaces, as compared to bulk TiAl and that ledges are weak barriers to dislocation glide. The interfaces themselves are strong barriers to dislocation motion in the hard mode. We find that the 1/2<110] screw dislocations gliding on conjugate {111} planes are trapped at these interfaces, as a result of lower core energies for screw dislocations lying in the interface.

Electrostatic contributions to the binding of Ca2+ in calbindin mutants. A Monte Carlo study

Monte Carlo simulation is used to calculate the free energy of binding of calcium ions to the native and several mutant forms of bovine calbindin D(9K) in salt solution. The simulations are performed in the canonical ensemble wherein free energies are calculated with a modified Widom method. The protein is modelled as a set of fixed hard spheres of fractional or unit charge with the surrounding solution as a dielectric continuum containing counterions and added salt particles. The interior of the protein is assumed to have the same dielectric permittivity as the solvent, which turns out to be an excellent approximation. Indeed, this simple model is able to predict accurately experimentally measured shifts in the calcium binding constants of up to five orders of magnitude, due to mutations and added salt.

Prediction of dislocation cores in aluminum from density functional theory

The strain field of isolated screw and edge dislocation cores in aluminum are calculated using density-functional theory and a flexible boundary condition method. Nye tensor density contours and differential displacement fields are used to accurately bound Shockley partial separation distances. Our results of 5-7.5 A (screw) and 7.0-9.5 A (edge) eliminate uncertainties resulting from the wide range of previous results based on Peierls-Nabarro and atomistic methods. Favorable agreement of the predicted cores with limited experimental measurements demonstrates the need for quantum mechanical treatment of dislocation cores.

Episodic ataxia and hemiplegia caused by the 8993T->C mitochondrial DNA mutation

The m.8993T-->C MTATP6 mutation of mitochondrial DNA (mtDNA) usually causes mitochondrial disease in childhood, but was recently described in a family with adult onset ataxia and polyneuropathy. Cytochrome c oxidase muscle histochemistry, which is the standard clinical investigation for mitochondrial disease in adults, is usually normal in patients with MTATP6 mutations. This raises the possibility that these cases have been missed in the past. We therefore studied 308 patients with unexplained ataxia and 96 patients with suspected Charcot-Marie-Tooth disease to determine whether the m.8993T-->C MTATP6 mutation is common in unexplained inherited ataxia and/or polyneuropathy. We identified a three-generation family with the m.8993T-->C mutation of mtDNA. One subject had episodic ataxia (EA) and transient hemipareses, broadening the phenotype. However, no further cases were identified in an additional cohort of 191 patients with suspected EA. In conclusion, m.8993T-->C MTATP6 should be considered in patients with unexplained ataxia, CMT or EA, but cases are uncommon.

Development of 17-allylamino-17-demethoxygeldanamycin hydroquinone hydrochloride (IPI-504), an anti-cancer agent directed against Hsp90

Heat shock protein 90 (Hsp90) is an emerging therapeutic target of interest for the treatment of cancer. Its role in protein homeostasis and the selective chaperoning of key signaling proteins in cancer survival and proliferation pathways has made it an attractive target of small molecule therapeutic intervention. 17-Allylamino-17-demethoxygeldanamycin (17-AAG), the most studied agent directed against Hsp90, suffers from poor physical-chemical properties that limit its clinical potential. Therefore, there exists a need for novel, patient-friendly Hsp90-directed agents for clinical investigation. IPI-504, the highly soluble hydroquinone hydrochloride derivative of 17-AAG, was synthesized as an Hsp90 inhibitor with favorable pharmaceutical properties. Its biochemical and biological activity was profiled in an Hsp90-binding assay, as well as in cancer-cell assays. Furthermore, the metabolic profile of IPI-504 was compared with that of 17-AAG, a geldanamycin analog currently in clinical trials. The anti-tumor activity of IPI-504 was tested as both a single agent as well as in combination with bortezomib in myeloma cell lines and in vivo xenograft models, and the retention of IPI-504 in tumor tissue was determined. In conclusion, IPI-504, a potent inhibitor of Hsp90, is efficacious in cellular and animal models of myeloma. It is synergistically efficacious with the proteasome inhibitor bortezomib and is preferentially retained in tumor tissues relative to plasma. Importantly, it was observed that IPI-504 interconverts with the known agent 17-AAG in vitro and in vivo via an oxidation-reduction equilibrium, and we demonstrate that IPI-504 is the slightly more potent inhibitor of Hsp90.

Deep Impact: observations from a worldwide Earth-based campaign

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

A link between mRNA turnover and RNA interference in Arabidopsis

In RNA interference (RNAi), double-stranded RNA (dsRNA) triggers degradation of homologous messenger RNA. In many organisms, RNA-dependent RNA polymerase (RdRp) is required to initiate or amplify RNAi, but the substrate for dsRNA synthesis in vivo is not known. Here, we show that RdRp-dependent transgene silencing in Arabidopsis was caused by mutation of XRN4, which is a ribonuclease (RNase) implicated in mRNA turnover by means of decapping and 5'-3' exonucleolysis. When both XRN4 and the RdRp were mutated, the plants accumulated decapped transgene mRNA. We propose that mRNAs lacking a cap structure become exposed to RdRp to initiate or maintain RNAi.

Comparison of selected analytical techniques for protein sizing, quantitation and molecular weight determination

Protein analysis techniques are developing fast due to the growing number of proteins obtained by recombinant DNA techniques. In the present paper we compare selected techniques, which are used for protein sizing, quantitation and molecular weight determination: sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE), lab-on-a-chip or microfluidics technology (LoaC), size exclusion chromatography (SEC) and mass spectrometry (MS). We compare advantages and limitations of each technique in respect to different application areas, analysis time, protein sizing and quantitation performance.