1613 A Case Study Implementing A Strength Training Programme with The Aim to Reduce the Risk of Osteosarcopenia And Bone Fractures

Aim

Strength training induces a mechanical load, both increasing muscle mass and enhancing osteoblast activity. This results in increased muscle and bone strength, reducing the risk of osteosarcopenia. Osteosarcopenia can start after the age of 30, putting patients at increased risk of bone fractures, with an untrained individual losing 0.23kg of muscle mass per year. In this case study, we illustrate a training programme, implemented over a period of 4 weeks on an untrained individual. The aim is to set an exemplar strengthening regimen for patients to reduce their risk of developing osteosarcopenia and bone fractures.

Method

One untrained novice subject was recruited. Two physical profile measurements were taken, prior to the start of the programme and at its conclusion. These included height, weight, BMI, lean body mass, muscle circumference and 1 repetition max (1RM) for upper body strength (bench press) and lower body strength (deadlift and squat).

Results

The subject had increased strength performance with increased 1RM, or equivalent, in the deadlift (+2.9kg), squat (+3kg) and bench press (+2.5kg) He also had a small increase in lean body mass of 0.1kg and increased body circumference in all muscle groups.

Conclusions

Our study shows that a simple strength training programme performed independently can lead to improved muscle strength and increased lean body mass. We illustrated that the programme can be performed inexpensively. Forthcoming, we would like to perform a prospective cohort study with the aim to implement a standardised programme within national guidelines for fracture risk-reduction.

An evolving role for endobronchial ultrasonography in the intensive care unit

Endobronchial ultrasound (EBUS) bronchoscopy is an established minimally-invasive modality for visualization, characterization, and guidance of sampling of paratracheal and parabronchial structures and tissues. In the intensive care unit (ICU), rapidly obtaining an accurate diagnosis is paramount to the management of critically ill patients. In some instances, diagnosing and confirming terminal illness in a critically ill patient provides needed closure for patients and their loved ones. Currently available data on feasibility, safety, and yield of EBUS bronchoscopy in critically ill patients is based on single center experiences. These data suggest that in select ICU patients convex and radial probe-EBUS bronchoscopy can serve as useful tools in the evaluation of mediastinal lymphadenopathy, central airway obstruction, pulmonary embolism, and peripheral lung lesions. Barriers to the use of EBUS bronchoscopy in the ICU include: (I) requirement for dedicated equipment, prolonged procedure time, and bronchoscopy team expertise that may not be available; (II) applicability to a limited number of patients and conditions in the ICU; and (III) technical difficulty related to the relatively large outer diameter of the convex probe-EBUS bronchoscope and an increased risk for adverse cardiopulmonary consequences due to intermittent obstruction of the artificial airway. While the prospects for EBUS bronchoscopy in critically ill patients appear promising, judicious patient selection in combination with bronchoscopy team expertise are of utmost importance when considering performance of EBUS bronchoscopy in the ICU setting.

Hemoptysis associated with percutaneous transthoracic needle biopsy: Development of critical events checklist and procedure outcomes

BACKGROUND

A percutaneous transthoracic needle biopsy (PTNB) is performed to obtain tissue for a pathologic diagnosis. A PTNB is necessary prior to the initiation of many cancer treatments. There is a risk of hemoptysis, the expectoration of blood, with the possibility for adverse, life-threatening outcomes. A critical event checklist is a cognitive aid used in an emergency to ensure critical steps are followed. To date, there are no known checklists published for management of PTNB-related, life-threatening hemoptysis. The purpose of this report is to describe the development and implementation of a critical event checklist and the adoption of the checklist into hemoptysis management.

METHODS

In March 2017, a process improvement team convened to evaluate the hemoptysis response using the Plan-Do-Study-Act (PDSA) methodology. The checklist was evaluated and updated through September 2019. The team educated Interventional Radiology (IR) clinicians on the new checklist and conducted simulations on its use. A retrospective chart review was performed on hemoptysis events between the ten-year period of October 1, 2008 and September 30, 2018 to evaluate the adoption of the checklist into practice.

RESULTS

There were 231 hemoptysis events occurring in 229 patients (2 with repeat biopsies). Prior to implementing the protocol and checklist, there were 166 (71.9%) hemoptysis events. After implementation there were 65 (28.1%) events. The median amount of documented blood expectorated with hemoptysis was 100 mL (IQR 20.0-300.0). Twenty-six patients were admitted after PTNB for reasons related to the hemoptysis event (11.3%). During the procedure, four (1.7%) patients with hemoptysis suffered a cardiac arrest. Prior to implementation of the protocol and critical events checklist, nurses positioned patients in the lateral decubitus (LD) position in 40 out of 162 (24.7%) cases. After implementation of the critical events checklist, nurses positioned patients in the LD position 42 out of 65 cases (64.6%) (OR=5.57(95% CI 2.99-10.367), p<0.001).

DISCUSSION

Interventional Radiology nurses successfully adopted the checklist into management of hemoptysis events. The reported incidence of hemoptysis suggests a need for IR teams to prepare for and simulate hemoptysis events. Future research is needed to evaluate the change in patient outcomes before and after critical events checklist implementation.

Replacing thymine with a strongly pairing fifth Base: A combined quantum mechanics and molecular dynamics study

The non-natural ethynylmethylpyridone C-nucleoside (W), a thymidine (T) analogue that can be incorporated in oligonucleotides by automated synthesis, has recently been reported to form a high fidelity base pair with adenosine (A) and to be well accommodated in B-DNA duplexes. The enhanced binding affinity for A of W, as compared to T, makes it an ideal modification for biotechnological applications, such as efficient probe hybridization for the parallel detection of multiple DNA strands. In order to complement the experimental study and rationalize the impact of the non-natural W nucleoside on the structure, stability and dynamics of DNA structures, we performed quantum mechanics (QM) calculations along with molecular dynamics (MD) simulations. Consistently with the experimental study, our QM calculations show that the A:W base pair has an increased stability as compared to the natural A:T pair, due to an additional CH-π interaction. Furthermore, we show that mispairing between W and guanine (G) causes a distortion in the planarity of the base pair, thus explaining the destabilization of DNA duplexes featuring a G:W pair. MD simulations show that incorporation of single or multiple consecutive A:W pairs in DNA duplexes causes minor changes to the intra- and inter-base geometrical parameters, while a moderate widening/shrinking of the major/minor groove of the duplexes is observed. QM calculations applied to selected stacks from the MD simulations also show an increased stacking energy for W, over T, with the neighboring bases.

Success and failure of additional immune modulators in steroid-refractory/resistant pneumonitis related to immune checkpoint blockade

BACKGROUND

Pneumonitis related to immune checkpoint blockade is uncommon but can be severe, fatal or chronic. Steroids are first-line treatment, however, some patients are refractory or become resistant to steroids. Like many immune-related adverse events, little is known regarding the outcomes and optimal management of patients in whom steroids are ineffective.

METHODS

We performed a single-center retrospective cohort study at a high-volume tertiary cancer center to evaluate the clinical course, management strategies and outcomes of patients treated for immune checkpoint pneumonitis with immune modulatory medications in addition to systemic steroids. Pharmacy records were queried for patients treated with both immune checkpoint blockade and receipt of additional immune modulators. Records were then manually reviewed to identify patients who received the additional immune modulators for immune checkpoint pneumonitis.

RESULTS

From 2013 to 2020, we identified 26 patients treated for immune checkpoint pneumonitis with additional immune modulators in addition to steroids. Twelve patients (46%) were steroid-refractory and 14 (54%) were steroid-resistant. Pneumonitis severity included grade 2 (42%) or grade 3-4 (58%). Additional immune modulation consisted of tumor necrosis factor-alpha inhibitor (77%) and/or mycophenolate (23%). Durable improvement in pneumonitis following initiation of additional immune modulators occurred in 10 patients (38%), including three patients (12%) in whom pneumonitis resolved and all immunosuppressants ceased. The rate of 90-day all-cause mortality/hospice referral was 50%. At last follow-up, mortality attributable to pneumonitis was 23%. In addition to mortality from pneumonitis and cancer, 3 patients (12%) died due to infections possibly associated with immunosuppression.

CONCLUSIONS

Steroid-refractory or -resistant immune checkpoint pneumonitis is uncommon but associated with significant morbidity and mortality. Additional immunomodulators can yield durable improvement, attained in over one third of patients. An improved understanding of the underlying biology of immune-related pneumonitis will be crucial to guide more precise and effective treatment strategies in the future.

Enzymatic Formation of an Artificial Base Pair Using a Modified Purine Nucleoside Triphosphate

The expansion of the genetic alphabet with additional, unnatural base pairs (UBPs) is an important and long-standing goal in synthetic biology. Nucleotides acting as ligands for the coordination of metal cations have advanced as promising candidates for such an expansion of the genetic alphabet. However, the inclusion of artificial metal base pairs in nucleic acids mainly relies on solid-phase synthesis approaches, and very little is known about polymerase-mediated synthesis. Herein, we report the selective and high yielding enzymatic construction of a silver-mediated base pair (dIm^C-Ag^I-dPur^P) as well as a two-step protocol for the synthesis of DNA duplexes containing such an artificial metal base pair. Guided by DFT calculations, we also shed light into the mechanism of formation of this artificial base pair as well as into the structural and energetic preferences. The enzymatic synthesis of the dIm^C-Ag^I-dPur^P artificial metal base pair provides valuable insights for the design of future, more potent systems aiming at expanding the genetic alphabet.

Occurrence and stability of lone pair-π and OH-π interactions between water and nucleobases in functional RNAs

We identified over 1000 instances of water-nucleobase stacking contacts in a variety of RNA molecules from a non-redundant set of crystal structures with resolution ≤3.0 Å. Such contacts may be of either the lone pair-π (lp-π) or the OH-π type, in nature. The distribution of the distances of the water oxygen from the nucleobase plane peaks at 3.5 Å for A, G and C, and approximately at 3.1-3.2 Å for U. Quantum mechanics (QM) calculations confirm, as expected, that the optimal energy is reached at a shorter distance for the lp-π interaction as compared to the OH-π one (3.0 versus 3.5 Å). The preference of each nucleobase for either type of interaction closely correlates with its electrostatic potential map. Furthermore, QM calculations show that for all the nucleobases a favorable interaction, of either the lp-π or the OH-π type, can be established at virtually any position of the water molecule above the nucleobase skeleton, which is consistent with the uniform projection of the OW atoms over the nucleobases ring we observed in the experimental occurrences. Finally, molecular dynamics simulations of a model system for the characterization of water-nucleobase stacking contacts confirm the stability of these interactions also under dynamic conditions.

Unravelling the utility of modern sulfonylureas from cardiovascular outcome trials and landmark trials: expert opinion from an international panel

AIM

The primary objective of this review is to develop practice-based expert group opinions on the cardiovascular (CV) safety and utility of modern sulfonylureas (SUs) in cardiovascular outcome trials (CVOTs).

BACKGROUND

The United States Food and Drug Administration issued new guidance to the pharmaceutical industry in 2008 regarding the development of new antihyperglycemic drugs. The guidance expanded the scope for the approval of novel antihyperglycemic drugs by mandating CVOTs for safety. A few long-term CVOTs on dipeptidyl peptidase 4 inhibitors, glucagon-like peptide 1 receptor agonists, and sodium-glucose cotransporter 2 inhibitors have been completed, while others are ongoing. SUs, which constitute one of the key antihyperglycemic agents used for the management of type 2 diabetes mellitus (T2DM), have been used as comparator agents in several CVOTs. However, the need for CVOTs on modern SUs remains debatable. In this context, a multinational group of endocrinologists convened for a meeting and discussed the need for CVOTs of modern SUs to evaluate their utility in the management of patients with T2DM. At the meeting, CVOTs of modern SUs conducted to date and the hypotheses derived from the results of these trials were discussed.

REVIEW RESULTS

The expert group analyzed the key trials emphasizing the CV safety of modern SUs and also reviewed the results of various CVOTs in which modern SUs were used as comparators. Based on literature evidence and individual clinical insights, the expert group opined that modern SUs are cardiosafe and that since they have been used as comparators in other CVOTs, CVOTs of SUs are not required.

CONCLUSION

Modern SUs can be considered a cardiosafe option for the management of patients with diabetes mellitus and CV disease; thus CVOTs among individuals with T2DM are not required.

Success and failure of additional immunosuppressants in steroid-refractory pneumonitis related to immune checkpoint blockade

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Background: Severe immune related adverse events (irAEs) with immune checkpoint blockade are uncommon but can be fatal. Steroids are the most common initial treatment for most non-endocrine irAEs, but some patients are or become refractory to steroids. When steroids are not effective, there is limited data to guide management strategies, particularly in the context of pneumonitis. Methods: All patients at MSK treated with immune checkpoint blockade from 2013-2020 were queried for receipt of an immunosuppressant (e.g. TNF antagonists, mycophenolate mofetil, cyclophosphamide) beyond steroids. Patient records were then manually reviewed to identify patients who received such therapy for management of immunotherapy-related pneumonitis. Results: Among 5363 patients treated with immune checkpoint blockade, 364 (6.8%) received an additional immunosuppressant for an irAE, including 28 (0.5% of all patients treated) patients treated for pneumonitis. Most of these pneumonitis events (19/28, 68%) were grade 3 or higher. Agents used included mycophenolate mofetil (7/28; 25%), TNF antagonists (23/28; 82%), and cyclophosphamide (1/28; 3.5%); more than one medication was used in 3 patients (11%). The indications were primary non-response to steroids (n = 16, 57%) and recrudescence after initial response to steroids (n = 12, 43%). At 90 days from initiation of the additional immunosuppressant, 13/28 (46%) patients were alive with improvement or resolution of pneumonitis while 15/28 (54%) had died. Survival with resolution/improvement was more common in patients treated for recrudescence vs primary non-response (67% vs 25%, p = 0.05). Conclusions: Outcomes with additional immunosuppressants in the setting of steroid-refractory immune-related pneumonitis are poor, but resolution can occur in some cases. A deeper understanding of the mechanistic underpinnings of irAEs is needed to more effectively tailor immunosuppressant therapies, particularly in severe pneumonitis events.

Structural and Energetic Impact of Non-natural 7-Deaza-8-azaguanine, 7-Deaza-8-azaisoguanine, and Their 7-Substituted Derivatives on Hydrogen-Bond Pairing with Cytosine and Isocytosine

The impact of 7-deaza-8-azaguanine (DAG) and 7-deaza-8-azaisoguanine (DAiG) modifications on the geometry and stability of the G:C Watson-Crick (cWW) base pair and the G:iC and iG:C reverse Watson-Crick (tWW) base pairs has been characterized theoretically. In addition, the effect on the same base pairs of seven C7-substituted DAG and DAiG derivatives, some of which have been previously experimentally characterized, has been investigated. Calculations indicate that all of these modifications have a negligible impact on the geometry of the above base pairs, and that modification of the heterocycle skeleton has a small impact on the base-pair interaction energies. Instead, base-pair interaction energies are dependent on the nature of the C7 substituent. For the 7-substituted DAG-C cWW systems, a linear correlation between the base-pair interaction energy and the Hammett constant of the 7-substituent is found, with higher interaction energies corresponding to more electron-withdrawing substituents. Therefore, the explored modifications are expected to be accommodated in both parallel and antiparallel nucleic acid duplexes without perturbing their geometry, while the strength of a base pair (and duplex) featuring a DAG modification can, in principle, be tuned by incorporating different substituents at the C7 position.

Paradoxical immune reconstitution inflammatory syndrome associated with disseminated tuberculosis infection in an unrelated donor cord blood transplant recipient

Tuberculosis (TB) is an infrequent infection after hematopoietic cell transplant (HCT), with associated mortality up to 30%. The utility of universal screening for latent TB in HCT candidates is controversial due to the lack of sensitive screening tests. We describe a case of disseminated TB infection complicated by immune reconstitution inflammatory syndrome in an adult double unit umbilical cord blood transplant recipient who originated from the United Arab Emirates.

Theoretical characterization of sulfur-to-selenium substitution in an emissive RNA alphabet: impact on H-bonding potential and photophysical properties

We employ density functional theory (DFT) and time-dependent DFT (TDDFT) calculations to investigate the structural, energetic and optical properties of a new computationally designed RNA alphabet, where the nucleobases, ^tsA, ^tsG, ^tsC, and ^tsU (ts-bases), have been derived by replacing sulfur with selenium in the previously reported tz-bases, based on the isothiazolo[4,3-d]pyrimidine heterocycle core. We find out that the modeled non-natural bases have minimal impact on the geometry and energetics of the classical Watson-Crick base pairs, thus potentially mimicking the natural bases in a RNA duplex in terms of H-bonding. In contrast, our calculations indicate that H-bonded base pairs involving the Hoogsteen edge of purines are destabilized as compared to their natural counterparts. We also focus on the photophysical properties of the non-natural bases and correlate their absorption/emission peaks to the strong impact of the modification on the energy of the lowest unoccupied molecular orbital. It is indeed stabilized by roughly 1.1-1.6 eV as compared to the natural analogues, resulting in a reduction of the gap between the highest occupied and the lowest unoccupied molecular orbital from 5.3-5.5 eV in the natural bases to 3.9-4.2 eV in the modified ones, with a consequent bathochromic shift in the absorption and emission spectra. Overall, our analysis clearly indicates that the newly modelled ts-bases are expected to exhibit better fluorescent properties as compared to the previously reported tz-bases, while retaining similar H-bonding properties. In addition, we show that a new RNA alphabet based on size-extended benzo-homologated ts-bases can also form stable Watson-Crick base pairs with the natural complementary nucleobases.

Collaborating with interventional pulmonology in managing a massive tracheoesophageal fistula that extends from cricoid to carina: a case report

Tracheoesophageal fistulas (TEF) present a perioperative management challenge. A 62 year-old man with esophageal carcinoma presented with a large tracheoesophageal fistula extending most of the trachea. Previously, the patient had two overlapping esophageal and one tracheal stent placed, but he developed progressive tracheal disruption due to esophageal stent perforation near the level of the cricoid. This case describes the anesthetic management of tracheal stent placement for an expanding TEF. Management included a spontaneous breathing inhalation induction followed by ventilation through a supraglottic device—laryngeal mask airway (LMA). Finally, during rigid bronchoscopy, a combination of bag ventilation and jet ventilation was utilized.

Energetics and dynamics of the non-natural fluorescent 4AP:DAP base pair

Quantum mechanics and molecular dynamics methods are used to compare the non-natural 4AP–DAP base pair to natural base pairs.

Occurrence and stability of lone pair-π stacking interactions between ribose and nucleobases in functional RNAs

The specific folding pattern and function of RNA molecules lies in various weak interactions, in addition to the strong base-base pairing and stacking. One of these relatively weak interactions, characterized by the stacking of the O4' atom of a ribose on top of the heterocycle ring of a nucleobase, has been known to occur but has largely been ignored in the description of RNA structures. We identified 2015 ribose-base stacking interactions in a high-resolution set of non-redundant RNA crystal structures. They are widespread in structured RNA molecules and are located in structural motifs other than regular stems. Over 50% of them involve an adenine, as we found ribose-adenine contacts to be recurring elements in A-minor motifs. Fewer than 50% of the interactions involve a ribose and a base of neighboring residues, while approximately 30% of them involve a ribose and a nucleobase at least four residues apart. Some of them establish inter-domain or inter-molecular contacts and often implicate functionally relevant nucleotides. In vacuo ribose-nucleobase stacking interaction energies were calculated by quantum mechanics methods. Finally, we found that lone pair-π stacking interactions also occur between ribose and aromatic amino acids in RNA-protein complexes.

Tumor Xenografts of Human Clear Cell Renal Cell Carcinoma But Not Corresponding Cell Lines Recapitulate Clinical Response to Sunitinib: Feasibility of Using Biopsy Samples

BACKGROUND

Parallel development of preclinical models that recapitulate treatment response observed in patients is central to the advancement of personalized medicine.

OBJECTIVE

To evaluate the use of biopsy specimens to develop patient-derived xenografts and the use of corresponding cell lines from renal cell carcinoma (RCC) tumors for the assessment of histopathology, genomics, and treatment response.

DESIGN, SETTING, AND PARTICIPANTS

A total of 74 tumor specimens from 66 patients with RCC were implanted into immunocompromised NOD-SCID IL2Rg-/- mice. Four cell lines generated from patients' specimens with clear cell pathology were used for comparative studies.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Preclinical models were established and assessed. Engraftment rates were analyzed using chi-square testing. Analysis of variance (two-way analysis of variance) was conducted to assess tumor growth.

RESULTS AND LIMITATIONS

Overall, 33 RCC mouse xenograft models were generated with an overall engraftment rate of 45% (33 of 74). Tumor biopsies engrafted comparably with surgically resected tumors (58% vs 41%; p=0.3). Xenograft tumors and their original tumors showed high fidelity in regard to histology, mutation status, copy number change, and targeted therapy response. Engraftment rates from metastatic tumors were higher but not more significant than primary tumors (54% vs 34%; p=0.091). Our engraftment rate using metastases or biopsies was comparable with recent reports using resected primary tumors. In stark contrast to corresponding cell lines, all tested xenografts recapitulated patients' clinical response to sunitinib.

CONCLUSIONS

Patient-derived xenograft models can be effectively established from tumor biopsies. Preclinical xenograft models but not matched cell lines reflected clinical responses to sunitinib.

PATIENT SUMMARY

Matched patient-derived clear cell renal cell carcinoma xenografts and cell lines from responsive and refractory patients treated with sunitinib were established and evaluated for pharmacologic response to anti-vascular endothelial growth factor treatment. Both models accurately reflected the genetic characteristics of original tumors, but only xenografts recapitulated drug responses observed in patients. These models could serve as a powerful platform for precision medicine.