Observations of Rogue Seas in the Southern Ocean.

We report direct observations of surface waves from a stereo camera system along with concurrent measurements of wind speed during an expedition across the Southern Ocean in the austral winter aboard the South African icebreaker S.A. Agulhas II. Records include water surface elevation across a range of wave conditions spanning from early stages of wave growth to full development. We give experimental evidence of rogue seas, i.e., sea states characterized by heavy tails of the probability density function well beyond the expectation based on bound mode theory. These conditions emerge during wave growth, where strong wind forcing and high nonlinearity drive wave dynamics. Quasiresonance wave-wave interactions, which are known to sustain the generation of large amplitude rogue waves, capture this behavior. Wave statistics return to normality as the wind forcing ceases and waves switch to a full developed condition.

Comparative Study of Nanoparticle Blood Circulation after Forced Clearance of Own Erythrocytes (Mononuclear Phagocyte System-Cytoblockade) or Administration of Cytotoxic Doxorubicin- or Clodronate-Loaded Liposomes.

Recent developments in the field of nanomedicine have introduced a wide variety of nanomaterials that are capable of recognizing and killing tumor cells with increased specificity. A major limitation preventing the widespread introduction of nanomaterials into the clinical setting is their fast clearance from the bloodstream via the mononuclear phagocyte system (MPS). One of the most promising methods used to overcome this limitation is the MPS-cytoblockade, which forces the MPS to intensify the clearance of erythrocytes by injecting allogeneic anti-erythrocyte antibodies and, thus, significantly prolongs the circulation of nanoagents in the blood. However, on the way to the clinical application of this approach, the question arises whether the induced suppression of macrophage phagocytosis via the MPS-cytoblockade could pose health risks. Here, we show that highly cytotoxic doxorubicin- or clodronate-loaded liposomes, which are widely used for cancer therapy and biomedical research, induce a similar increase in the nanoparticle blood circulation half-life in mice as the MPS-cytoblockade, which only gently and temporarily saturates the macrophages with the organism's own erythrocytes. This result suggests that from the point of view of in vivo macrophage suppression, the MPS-cytoblockade should be less detrimental than the liposomal anti-cancer drugs that are already approved for clinical application while allowing for the substantial improvement in the nanoagent effectiveness.

The Biological and Clinical Aspects of a Latent Tuberculosis Infection.

Tuberculosis (TB), caused by bacilli from the Mycobacterium tuberculosis complex, remains a serious global public health problem, representing one of the main causes of death from infectious diseases. About one quarter of the world's population is infected with Mtb and has a latent TB infection (LTBI). According to the World Health Organization (WHO), an LTBI is characterized by a lasting immune response to Mtb antigens without any TB symptoms. Current LTBI diagnoses and treatments are based on this simplified definition, although an LTBI involves a broad range of conditions, including when Mtb remains in the body in a persistent form and the immune response cannot be detected. The study of LTBIs has progressed in recent years; however, many biological and medical aspects of an LTBI are still under discussion. This review focuses on an LTBI as a broad spectrum of states, both of the human body, and of Mtb cells. The problems of phenotypic insusceptibility, diagnoses, chemoprophylaxis, and the necessity of treatment are discussed. We emphasize the complexity of an LTBI diagnosis and its treatment due to its ambiguous nature. We consider alternative ways of differentiating an LTBI from active TB, as well as predicting TB reactivation based on using mycobacterial "latency antigens" for interferon gamma release assay (IGRA) tests and the transcriptomic analysis of human blood cells.

Impact of previous corticosteroid exposure on outcomes of patients receiving immune checkpoint inhibitors for advanced non-small cell lung cancer: a retrospective observational study.

BACKGROUND: Immunosuppressive dosing of corticosteroids at the start of treatment impairs immune checkpoint inhibitor (ICI) efficacy in advanced non-small cell lung cancer (NSCLC). Previous cumulative dose and intake modality of corticosteroids may result in different levels of immunosuppression. We sought to determine whether these aspects could predict disease control and survival in NSCLC patients receiving ICIs. METHODS: We conducted a retrospective single-center study, including patients treated with ICI as second-line therapy at our institution between July 2015 and February 2021. A prednisone equivalent threshold of 700 mg defined low (LCD) or high (HCD) cumulative dosing during the 90 days before starting ICIs. At least one 5-day course of ≥ 10 mg prednisone equivalent determined whether the intake was pulse (PCD, ≤ 5 days) or continuous (CCD, > 5 days). RESULTS: We included 113 consecutive patients. Durable control benefit and no clinical benefit (NCB) were reported in 53 (47%) and 60 (53%) of the cases, respectively. ECOG PS 1-2, negative PD-L1 expression, HCD, and CCD were significantly related to NCB in multivariate analysis. The median PFS was 4.6 months (95%CI: 3.9-6.3) and median OS was 6.9 months (95% CI: 6.0-8.9) after a median follow-up time of 43.5 months (95% CI: 32.6-54.4). Multivariate analysis of survival confirmed ECOG PS 1-2 (p = 0.005), negative PD-L1 expression (p = 0.002), and CCD (p = 0.001) significantly correlated with an increased risk of mortality. CONCLUSIONS: These findings imply that immunosuppressive corticosteroid dosing before ICIs, even of short duration, might affect survival. The constraints of this study and lack of reliable comparisons suggest a hypothesis-generating value of these results.

Antineoplastic treatment class modulates COVID-19 mRNA-BNT162b2 vaccine immunogenicity in cancer patients: a secondary analysis of the prospective Vax-On study.

BACKGROUND: Preliminary analysis from the Vax-On study did not find a correlation between cancer treatment type and antibody response to COVID-19 vaccination. We carried out a secondary subgroup analysis to verify the effects of comprehensive cancer treatment classification on vaccine immunogenicity. METHODS: The Vax-On study prospectively enrolled patients who started a two-dose messenger RNA-BNT162b2 vaccine schedule from 9 March 2021 to 12 April 2021 (timepoint-1). Those on active treatment within the previous 28 days accounted for the exposed cases. Patients who had discontinued such treatment by at least 28 days or received intravesical therapy represented the control cases. Quantification of immunoglobulin G (IgG) antibodies against the receptor binding domain of the S1 subunit of the SARS-CoV-2 spike protein was carried out before the second dose (timepoint-2) and 8 weeks thereafter (timepoint-3). Seroconversion response was defined at ≥50 arbitrary units/ml IgG titer. Classification of antineoplastic agents was based on their pharmacodynamic properties. RESULTS: Three hundred and sixty-six patients were enrolled (86 and 260 as control and exposed cases, respectively). Univariate analysis revealed a significantly lower IgG titer after both doses of vaccine in subgroups treated with tyrosine kinase inhibitors (TKIs), multiple cytotoxic agents, alkylating agents, and topoisomerase inhibitors. At timepoint-3, seroconversion response was significantly impaired in the topoisomerase inhibitors and mechanistic target of rapamycin (mTOR) inhibitors subgroups. After multivariate testing, treatment with alkylating agents and TKIs was significantly associated with a reduced change in IgG titer at timepoint-2. Treatment with mTOR inhibitors resulted in a similar interaction at each timepoint. Cyclin-dependent kinase 4/6 inhibitor treatment was independently correlated with an incremental variation in IgG titer at timepoint-3. Specific subgroups (TKIs, antimetabolites, alkylating agents, and multiple-agent chemotherapy) predicted lack of seroconversion at timepoint-2, but their effect was not retained at timepoint-3. Eastern Cooperative Oncology Group performance status 2, immunosuppressive corticosteroid dosing, and granulocyte colony-stimulating factor use were independently linked to lower IgG titer after either dose of vaccine. CONCLUSIONS: Drugs interfering with DNA synthesis, multiple-agent cytotoxic chemotherapy, TKIs, mTOR and cyclin-dependent kinase 4/6 inhibitors differentially modulate humoral response to messenger RNA-BNT162b2 vaccine.

Structure of ribosome-bound azole-modified peptide phazolicin rationalizes its species-specific mode of bacterial translation inhibition.

Ribosome-synthesized post-translationally modified peptides (RiPPs) represent a rapidly expanding class of natural products with various biological activities. Linear azol(in)e-containing peptides (LAPs) comprise a subclass of RiPPs that display outstanding diversity of mechanisms of action while sharing common structural features. Here, we report the discovery of a new LAP biosynthetic gene cluster in the genome of Rhizobium Pop5, which encodes the precursor peptide and modification machinery of phazolicin (PHZ) - an extensively modified peptide exhibiting narrow-spectrum antibacterial activity against some symbiotic bacteria of leguminous plants. The cryo-EM structure of the Escherichia coli 70S-PHZ complex reveals that the drug interacts with the 23S rRNA and uL4/uL22 proteins and obstructs ribosomal exit tunnel in a way that is distinct from other compounds. We show that the uL4 loop sequence determines the species-specificity of antibiotic action. PHZ expands the known diversity of LAPs and may be used in the future as biocontrol agent for agricultural needs.

Structure of Dirithromycin Bound to the Bacterial Ribosome Suggests New Ways for Rational Improvement of Macrolides.

Although macrolides are known as excellent antibacterials, their medical use has been significantly limited due to the spread of bacterial drug resistance. Therefore, it is necessary to develop new potent macrolides to combat the emergence of drug-resistant pathogens. One of the key steps in rational drug design is the identification of chemical groups that mediate binding of the drug to its target and their subsequent derivatization to strengthen drug-target interactions. In the case of macrolides, a few groups are known to be important for drug binding to the ribosome, such as desosamine. Search for new chemical moieties that improve the interactions of a macrolide with the 70S ribosome might be of crucial importance for the invention of new macrolides. For this purpose, here we studied a classic macrolide, dirithromycin, which has an extended (2-methoxyethoxy)-methyl side chain attached to the C-9/C-11 atoms of the macrolactone ring that can account for strong binding of dirithromycin to the 70S ribosome. By solving the crystal structure of the 70S ribosome in complex with dirithromycin, we found that its side chain interacts with the wall of the nascent peptide exit tunnel in an idiosyncratic fashion: its side chain forms a lone pair-π stacking interaction with the aromatic imidazole ring of the His69 residue in ribosomal protein uL4. To our knowledge, the ability of this side chain to form a contact in the macrolide binding pocket has not been reported previously and potentially can open new avenues for further exploration by medicinal chemists developing next-generation macrolide antibiotics active against resistant pathogens.

Mechanistic insights into the slow peptide bond formation with D-amino acids in the ribosomal active site.

During protein synthesis, ribosomes discriminate chirality of amino acids and prevent incorporation of D-amino acids into nascent proteins by slowing down the rate of peptide bond formation. Despite this phenomenon being known for nearly forty years, no structures have ever been reported that would explain the poor reactivity of D-amino acids. Here we report a 3.7Å-resolution crystal structure of a bacterial ribosome in complex with a D-aminoacyl-tRNA analog bound to the A site. Although at this resolution we could not observe individual chemical groups, we could unambiguously define the positions of the D-amino acid side chain and the amino group based on chemical restraints. The structure reveals that similarly to L-amino acids, the D-amino acid binds the ribosome by inserting its side chain into the ribosomal A-site cleft. This binding mode does not allow optimal nucleophilic attack of the peptidyl-tRNA by the reactive α-amino group of a D-amino acid. Also, our structure suggests that the D-amino acid cannot participate in hydrogen-bonding with the P-site tRNA that is required for the efficient proton transfer during peptide bond formation. Overall, our work provides the first mechanistic insight into the ancient mechanism that helps living cells ensure the stereochemistry of protein synthesis.

Co-produced natural ketolides methymycin and pikromycin inhibit bacterial growth by preventing synthesis of a limited number of proteins.

Antibiotics methymycin (MTM) and pikromycin (PKM), co-produced by Streptomyces venezuelae, represent minimalist macrolide protein synthesis inhibitors. Unlike other macrolides, which carry several side chains, a single desosamine sugar is attached to the macrolactone ring of MTM and PKM. In addition, the macrolactone scaffold of MTM is smaller than in other macrolides. The unusual structure of MTM and PKM and their simultaneous secretion by S. venezuelae bring about the possibility that two compounds would bind to distinct ribosomal sites. However, by combining genetic, biochemical and crystallographic studies, we demonstrate that MTM and PKM inhibit translation by binding to overlapping sites in the ribosomal exit tunnel. Strikingly, while MTM and PKM readily arrest the growth of bacteria, ∼40% of cellular proteins continue to be synthesized even at saturating concentrations of the drugs. Gel electrophoretic analysis shows that compared to other ribosomal antibiotics, MTM and PKM prevent synthesis of a smaller number of cellular polypeptides illustrating a unique mode of action of these antibiotics.

Klebsazolicin inhibits 70S ribosome by obstructing the peptide exit tunnel.

Whereas screening of the small-molecule metabolites produced by most cultivatable microorganisms often results in the rediscovery of known compounds, genome-mining programs allow researchers to harness much greater chemical diversity, and result in the discovery of new molecular scaffolds. Here we report the genome-guided identification of a new antibiotic, klebsazolicin (KLB), from Klebsiella pneumoniae that inhibits the growth of sensitive cells by targeting ribosomes. A ribosomally synthesized post-translationally modified peptide (RiPP), KLB is characterized by the presence of a unique N-terminal amidine ring that is essential for its activity. Biochemical in vitro studies indicate that KLB inhibits ribosomes by interfering with translation elongation. Structural analysis of the ribosome-KLB complex showed that the compound binds in the peptide exit tunnel overlapping with the binding sites of macrolides or streptogramin-B. KLB adopts a compact conformation and largely obstructs the tunnel. Engineered KLB fragments were observed to retain in vitro activity, and thus have the potential to serve as a starting point for the development of new bioactive compounds.

Madumycin II inhibits peptide bond formation by forcing the peptidyl transferase center into an inactive state.

The emergence of multi-drug resistant bacteria is limiting the effectiveness of commonly used antibiotics, which spurs a renewed interest in revisiting older and poorly studied drugs. Streptogramins A is a class of protein synthesis inhibitors that target the peptidyl transferase center (PTC) on the large subunit of the ribosome. In this work, we have revealed the mode of action of the PTC inhibitor madumycin II, an alanine-containing streptogramin A antibiotic, in the context of a functional 70S ribosome containing tRNA substrates. Madumycin II inhibits the ribosome prior to the first cycle of peptide bond formation. It allows binding of the tRNAs to the ribosomal A and P sites, but prevents correct positioning of their CCA-ends into the PTC thus making peptide bond formation impossible. We also revealed a previously unseen drug-induced rearrangement of nucleotides U2506 and U2585 of the 23S rRNA resulting in the formation of the U2506•G2583 wobble pair that was attributed to a catalytically inactive state of the PTC. The structural and biochemical data reported here expand our knowledge on the fundamental mechanisms by which peptidyl transferase inhibitors modulate the catalytic activity of the ribosome.

A retrospective study on female urological surgeries over the 10 years following spinal cord lesion.

OBJECTIVES: To evaluate the efficacy and safety over a 10-year period of any urological operations required by female patients with spinal cord lesions (SCLs). METHODS: Retrospective study of urological surgeries from our database performed on females with SCLs from 2001 to 2002. Surgery efficacy for neurogenic lower urinary tract dysfunctions (N-LUTDs) was evaluated by comparing 7-day voiding diaries pre- and post-surgeries, while individual investigations were done pre- and post-surgery to evaluate urological complications. Drawbacks were assessed. RESULTS: Thirty-eight out of 69 patients underwent one or more urological procedures. Twenty-one out of 42 patients with suprasacral lesions underwent interventions for N-LUTD. The main surgical treatment was endoscopic detrusor infiltration of botulinum-A (Botox 300 UI or Dysport 750 UI) performed 107 times on 15 subjects using aseptic intermittent catheterizations for neurogenic overactive bladder. Mean efficacy duration was 9.2 months. Six females with infrasacral lesions underwent at least one intervention for N-LUTD. Two females in each group underwent tension-free vaginal tape for stress urinary incontinence (SUI), reducing episodes per week of SUI by >90% after 5 years. The most serious urological complication was active vesico-ureteral reflux (VUR) in three patients, treated endoscopically with submucosal injection of Macroplastique. No VUR recurrence was detected during a 6-year follow-up. All bladder stones (five cases) and renal calculi (five cases) were treated with endoscopic transurethrally electrohydraulic lithotripsy and extracorporeal shock-wave lithotripsy, respectively. Overall, no serious drawbacks were observed. CONCLUSIONS: Mini-invasive surgeries were exclusively used to address urological issues in chronic SCL patients.

Intravesical electrostimulation versus sacral neuromodulation for incomplete spinal cord patients suffering from neurogenic non-obstructive urinary retention.

OBJECTIVES: To compare the efficacy of intravesical electrostimulation (IVES) versus sacral neuromodulation (SNM) in patients with incomplete spinal cord lesions (SCL) and neurogenic non-obstructive urinary retention (N-NOR). METHODS: In this retrospective study, 77 N-NOR patients underwent IVES (minimum 28 sessions), then after returning to voiding baseline symptoms, percutaneous first stage of SNM (lasting for minimum 4 weeks). After the two neuromodulation treatments, responders were categorized as patients experiencing both a 50% reduction of volume per catheterization per ml and a 50% reduction in number of catheterizations per day when comparing the 7-day voiding diaries at the end of both procedures to baselines. New urodynamics were performed subsequently. Responders to first stage of SNM underwent permanent SNM. RESULTS: Forty-eight patients responded to neither of the treatments, whereas 29 responded to both IVES and first-stage SNM. No significant statistical differences (P>0.05) were detected in the voiding diaries. Following the two procedures, the first sensation of bladder filling was either maintained or recovered by all responders, whereas the same 11 patients reached a bladder contractility index of >100. The 29 IVES responders lost their clinical benefits in a mean follow-up of 9.6 months. Only 10 out of the 29 patients became nonresponsive to permanent SNM, in a mean follow-up of 54 months. CONCLUSION: A strict correlation in terms of clinical and urodynamic patterns was demonstrated in patients with incomplete SCL and N-NOR, following IVES and first stage of SNM. However, voiding improvement through IVES was short-term when compared with the effects of permanent SNM.

Clinical efficacy of intravesical electrostimulation on incomplete spinal cord patients suffering from chronic neurogenic non-obstructive retention: a 15-year single centre retrospective study.

OBJECTIVE: To evaluate the clinical and urodynamic impact of intravesical electrostimulation (IVES) on incomplete spinal cord injury (SCI) patients suffering from chronic neurogenic non-obstructive urinary retention (N-NOR). METHODS: One-hundred and two patients underwent at least 28 consecutive daily IVES sessions because objective evidence of detrusor acontractility instead of hypocontractility was detected. Diary entries written at various stages by each patient were compared (7 days before the IVES cycle, 15-21 days into the cycle and 7 days before its end). Responders were patients with a mean 50% reduction in both the number of daily catheterizations and post-void residual urine. Responders underwent further urodynamics at the end of the IVES cycle; patients experiencing first sensation of bladder filling, and the mean volume of first sensation of bladder filling per ml, Qmax ml s(-1), among others, were evaluated. Nineteen individuals who repeated another IVES round were included in this study. RESULTS: Thirty-eight subjects (37.2%) responded to IVES and of those, 83.3% recovered the first sensation of bladder filling after the IVES round. Nineteen responders repeated IVES within 1 year, owing to loss of efficacy. They obtained similar voiding symptoms improvement and urodynamic results as after the first IVES cycle. A timespan of <2 years from SCI to IVES, and the presence of first sensation of bladder filling at baseline represented significant predictive parameters for IVES success (P<0.05) using χ(2)-test. CONCLUSIONS: IVES represents a possible therapeutic option for incomplete SCI patients with N-NOR.

Controversy over the pharmacological treatments of storage symptoms in spinal cord injury patients: a literature overview.

STUDY DESIGN: Our aim was to locate research and communicate the evidence found from scientific studies pertaining to the treatment of neurogenic detrusor overactivity (NDO) in the chronic stage of spinal cord injury (SCI). OBJECTIVE: To address the controversy over the traditional (antimuscarinics) and the 'new' treatments for NDO and try to offer an insight on the rationale underlying the development of new drugs such as botulinum toxin (BTX), vanilloids, nociceptin/orphanin FQ. As a final point, to provide information on a new class of cation channels, the Degenerin/Epithelial Na(+)Channel (Deg/ENaC) Family that could be future targets for the management of NDO. SETTING: International. METHODS: Overview of English literature on drug management of NDO. RESULTS: Agents that block the 'efferent' function of micturition reflex, such as antimuscarinics, are currently first-line therapy for NDO. They reach the highest level of evidence (1a) and grade of recommendation (A). However, many patients and physicians believe that the 'efferent' pharmacological management of NDO is not completely satisfactory. Consequently, research is trying to address issues of efficacy, tolerability and convenience of new therapeutic strategies targeting the 'afferent' function. CONCLUSION: Antimuscarinic therapy increases the bladder capacity and delays the initial urge to void. However, in some patients they fail to achieve the patient's therapeutic goals. New interesting approaches have been investigated in the last few years. BTX seems to be very promising in treating neurogenic overactive bladder (OAB), but other compounds are now on the horizon.

Clinical concomitant benefits on pelvic floor dysfunctions after sacral neuromodulation in patients with incomplete spinal cord injury.

OBJECTIVES: To assess the concomitant clinical improvement in incomplete spinal cord injury patients (SCIPs) suffering from neurogenic bowel symptoms (NBSs), neurogenic lower urinary tract symptoms (NLUTSs) and neurogenic erectile dysfunction (NED) using sacral neuromodulation (SNM) for NBSs and NLUTSs. METHODS: Seventy-five SCIPs were selected. Before and during the follow-ups post-SNM, NLUTSs and NBSs were detected mainly through specific diaries. Erectile function was assessed using the International Index of Erectile Function composed of 5 questions (IIEF5). Quality of life (QoL) was measured with the Short Form 36 Health Survey questionnaire (SF-36). During the first stage, in which a permanent electrode was inserted percutaneously into the third sacral foramina and stimulated using an external generator, patients with NBSs or NLUTSs were required to improve their symptoms by at least 50% compared with baseline before proceeding to the second stage in which the generator was placed in the patient's buttock. NED patients needed to increase their IIEF5 score by at least 25% compared with baseline (evaluated initially 3 months after the second stage) in order to continue follow-up. RESULTS: Fourteen out of 37 subjects who manifested two functional pelvic dysfunctions at baseline maintained notable clinical improvement in two pelvic functions (median follow-up >3 years). Six had non-obstructive retention (NOR) and NED, six double incontinence, and two constipation with NOR. In the general and mental health domains of the SF-36, all patients improved their scores by at least 20% compared with baseline. CONCLUSIONS: SNM may be beneficial to selected incomplete SCIP with concomitant pelvic functional disturbances.