Structural Basis of Poxvirus Transcription: Vaccinia RNA Polymerase Complexes.

Poxviruses encode a multisubunit DNA-dependent RNA polymerase (vRNAP) that carries out viral gene expression in the host cytoplasm. We report cryo-EM structures of core and complete vRNAP enzymes from Vaccinia virus at 2.8 Å resolution. The vRNAP core enzyme resembles eukaryotic RNA polymerase II (Pol II) but also reveals many virus-specific features, including the transcription factor Rap94. The complete enzyme additionally contains the transcription factor VETF, the mRNA processing factors VTF/CE and NPH-I, the viral core protein E11, and host tRNAGln. This complex can carry out the entire early transcription cycle. The structures show that Rap94 partially resembles the Pol II initiation factor TFIIB, that the vRNAP subunit Rpo30 resembles the Pol II elongation factor TFIIS, and that NPH-I resembles chromatin remodeling enzymes. Together with the accompanying paper (Hillen et al., 2019), these results provide the basis for unraveling the mechanisms of poxvirus transcription and RNA processing.

Structure and flexibility of the DNA polymerase holoenzyme of vaccinia virus.

The year 2022 was marked by the mpox outbreak caused by the human monkeypox virus (MPXV), which is approximately 98% identical to the vaccinia virus (VACV) at the sequence level with regard to the proteins involved in DNA replication. We present the production in the baculovirus-insect cell system of the VACV DNA polymerase holoenzyme, which consists of the E9 polymerase in combination with its co-factor, the A20-D4 heterodimer. This led to the 3.8 Å cryo-electron microscopy (cryo-EM) structure of the DNA-free form of the holoenzyme. The model of the holoenzyme was constructed from high-resolution structures of the components of the complex and the A20 structure predicted by AlphaFold 2. The structures do not change in the context of the holoenzyme compared to the previously determined crystal and NMR structures, but the E9 thumb domain became disordered. The E9-A20-D4 structure shows the same compact arrangement with D4 folded back on E9 as observed for the recently solved MPXV holoenzyme structures in the presence and the absence of bound DNA. A conserved interface between E9 and D4 is formed by a cluster of hydrophobic residues. Small-angle X-ray scattering data show that other, more open conformations of E9-A20-D4 without the E9-D4 contact exist in solution using the flexibility of two hinge regions in A20. Biolayer interferometry (BLI) showed that the E9-D4 interaction is indeed weak and transient in the absence of DNA although it is very important, as it has not been possible to obtain viable viruses carrying mutations of key residues within the E9-D4 interface.

More Than Just Closed and Open: Unraveling a Mechanosensor.

The bacterial mechanosensitive channel of small conductance (MscS) is a well-studied model of how mechanical forces from the membrane can be sensed by an embedded protein. A recent study by Zhang et al. visualizes how MscS behaves under membrane tension, entering a desensitized state when it loses all coordinated lipids.

Architecture of the mycobacterial type VII secretion system.

Host infection by pathogenic mycobacteria, such as Mycobacterium tuberculosis, is facilitated by virulence factors that are secreted by type VII secretion systems1. A molecular understanding of the type VII secretion mechanism has been hampered owing to a lack of three-dimensional structures of the fully assembled secretion apparatus. Here we report the cryo-electron microscopy structure of a membrane-embedded core complex of the ESX-3/type VII secretion system from Mycobacterium smegmatis. The core of the ESX-3 secretion machine consists of four protein components-EccB3, EccC3, EccD3 and EccE3, in a 1:1:2:1 stoichiometry-which form two identical protomers. The EccC3 coupling protein comprises a flexible array of four ATPase domains, which are linked to the membrane through a stalk domain. The domain of unknown function (DUF) adjacent to the stalk is identified as an ATPase domain that is essential for secretion. EccB3 is predominantly periplasmatic, but a small segment crosses the membrane and contacts the stalk domain. This suggests that conformational changes in the stalk domain-triggered by substrate binding at the distal end of EccC3 and subsequent ATP hydrolysis in the DUF-could be coupled to substrate secretion to the periplasm. Our results reveal that the architecture of type VII secretion systems differs markedly from that of other known secretion machines2, and provide a structural understanding of these systems that will be useful for the design of antimicrobial strategies that target bacterial virulence.

Ncs2* mediates in vivo virulence of pathogenic yeast through sulphur modification of cytoplasmic transfer RNA.

Fungal pathogens threaten ecosystems and human health. Understanding the molecular basis of their virulence is key to develop new treatment strategies. Here, we characterize NCS2*, a point mutation identified in a clinical baker's yeast isolate. Ncs2 is essential for 2-thiolation of tRNA and the NCS2* mutation leads to increased thiolation at body temperature. NCS2* yeast exhibits enhanced fitness when grown at elevated temperatures or when exposed to oxidative stress, inhibition of nutrient signalling, and cell-wall stress. Importantly, Ncs2* alters the interaction and stability of the thiolase complex likely mediated by nucleotide binding. The absence of 2-thiolation abrogates the in vivo virulence of pathogenic baker's yeast in infected mice. Finally, hypomodification triggers changes in colony morphology and hyphae formation in the common commensal pathogen Candida albicans resulting in decreased virulence in a human cell culture model. These findings demonstrate that 2-thiolation of tRNA acts as a key mediator of fungal virulence and reveal new mechanistic insights into the function of the highly conserved tRNA-thiolase complex.

Anticipated time to seek medical advice for possible lung cancer symptoms and barriers to timely presentation in Palestine: a national cross-sectional study.

BACKGROUND: Lung cancer (LC) has poor survival outcomes mainly due to diagnosis at late stages. This study explored the anticipated time to seek medical advice for possible LC symptoms and barriers to early presentation in Palestine. METHODS: This cross-sectional study recruited adult participants from hospitals, primary healthcare centers, and public spaces of 11 governorates using convenience sampling. A modified, translated-into-Arabic version of the validated LC awareness measure was used to assess LC symptom awareness, the time needed to seek medical advice and barriers to early presentation. RESULTS: A total of 4762 participants were included. The proportion that would immediately seek medical advice for possible LC symptoms varied according to the symptoms' nature. For respiratory symptoms, this ranged from 15.0% for 'painful cough' to 37.0% for 'coughing up blood'. For non-respiratory symptoms, this ranged from '4.2% for 'unexplained loss of appetite' to 13.8% for 'changes in the shape of fingers or nails'. Participants with good LC symptom awareness were more likely to seek medical advice within a week of recognizing most LC symptoms. About 13.0% would delay their visit to see a doctor after recognizing an LC symptom. The most reported barriers were emotional with 'disliking the visit to healthcare facilities' (59.8%) as the leading barrier. CONCLUSION: LC respiratory symptoms were more likely to prompt early seeking of medical advice. Good LC symptom awareness was associated with a higher likelihood of help-seeking within a week. Educational interventions are needed to promote LC awareness and address the perceived barriers to early presentation in low-resource settings, such as Palestine.

Understanding the interplay of colorectal cancer awareness and attitudes among Palestinians: a national cross-sectional study.

BACKGROUND: In Palestine, colorectal cancer (CRC) is the second most common cause of cancer-related mortality after lung cancer. No studies have examined the relationship between CRC awareness and attitudes. This study aimed to investigate the interplay between CRC awareness and attitudes among the Palestinian population. METHODS: A nationwide cross-sectional survey was carried out between July 2019 and March 2020. Convenience sampling was used to collect data from hospitals, primary healthcare facilities, and public areas in 11 governorates. Modified, translated-into-Arabic versions of the validated Bowel Cancer Awareness Measure and Cancer Awareness Measure-Mythical Causes Scale were utilized to assess the awareness of CRC signs/symptoms, risk factors, and causation myths. The cumulative awareness score for each domain was computed and stratified into tertiles. The top tertile denoted 'high' awareness, while the remaining two tertiles denoted 'low' awareness. RESULTS: The final analysis included 4,623 participants; of whom, 3115 (67.4%) reported positive attitudes toward CRC. In total, 1,849 participants (40.0%) had high awareness of CRC signs/symptoms. There was no association between displaying a high awareness of CRC signs/symptoms and having positive attitudes toward CRC. A total of 1,840 participants (38.9%) showed high awareness of CRC risk factors. Participants with high CRC risk factor awareness were more likely to display positive attitudes toward CRC (OR = 1.22, 95% CI: 1.07-1.39). Only 219 participants (4.7%) had high awareness of CRC causation myths. Participants with high awareness of CRC causation myths were more likely to exhibit positive attitudes toward CRC (OR = 2.48, 95% CI: 1.71-3.58). CONCLUSION: A high awareness level of CRC risk factors and causation myths was associated with a greater likelihood of demonstrating positive attitudes toward CRC in terms of perceived susceptibility, importance of early detection, and consequences of developing the disease. Future educational interventions should focus on raising public awareness about CRC, with a particular emphasis on risk factors and causation myths, to maximize the potential for shaping favorable attitudes toward the disease.

Mechanochemical removal of ribosome biogenesis factors from nascent 60S ribosomal subunits.

The dynein-related AAA ATPase Rea1 is a preribosomal factor that triggers an unknown maturation step in 60S subunit biogenesis. Using electron microscopy, we show that Rea1's motor domain is docked to the pre-60S particle and its tail-like structure, harboring a metal ion-dependent adhesion site (MIDAS), protrudes from the preribosome. Typically, integrins utilize a MIDAS to bind extracellular ligands, an interaction that is strengthened under applied tensile force. Likewise, the Rea1 MIDAS binds the preribosomal factor Rsa4, which is located on the pre-60S subunit at a site that is contacted by the flexible Rea1 tail. The MIDAS-Rsa4 interaction is essential for ATP-dependent dissociation of a group of non-ribosomal factors from the pre-60S particle. Thus, Rea1 aligns with its interacting partners on the preribosome to effect a necessary step on the path to the export-competent 60S subunit.

Common misconceptions and myths about ovarian cancer causation: a national cross-sectional study from palestine.

BACKGROUND: Women's inability to recognize ovarian cancer (OC) causation myths to be incorrect may lead to behavioral changes that could distract them from actual risk factors and impact their treatment decision making. This study examined Palestinian women's recognition of OC mythical causes, and explored factors associated with good recognition. METHODS: A national cross-sectional study was conducted. Adult Palestinian women were recruited from hospitals, primary healthcare facilities, and public areas in 11 governorates. The Cancer Awareness Measure-Mythical Causes Scale was modified and utilized for data collection. Awareness level was determined based on the number of myths around OC causation recognized to be incorrect: poor (0-4), fair (5-9), and good (10-13). RESULTS: A total of 5618 participants agreed and completed the questionnaire out of 6095 approached (response rate = 92.1%), and 5411 questionnaires were included in the final analysis. The most recognized food-related myth was 'drinking from plastic bottles' (n = 1370, 25.3%) followed by 'eating burnt food' (n = 1298, 24.0%). The least recognized food-related myth was 'eating food containing additives' (n = 611, 11.3%). The most recognized food-unrelated myth was 'having a physical trauma' (n = 2899, 53.6%), whereas the least recognized was 'using mobile phones' (n = 1347, 24.9%). Only 273 participants (5.1%) had good awareness of OC causation myths as incorrect. Earning higher monthly incomes as well as visiting governmental healthcare facilities were associated with a decrease in the likelihood of exhibiting good awareness. CONCLUSION: The overall recognition of OC causation myths was low. Addressing mythical beliefs should be included in OC prevention strategies and public health interventions to improve women's understanding of OC risk factors versus mythical causes.

Myths and common misbeliefs about cervical cancer causation among Palestinian women: a national cross-sectional study.

BACKGROUND: Cervical cancer (CC) myths and beliefs can negatively impact women's preventive behaviors, including vaccination against human papillomavirus and having regular screening tests. This study aimed to examine awareness of Palestinian women about myths related to CC causation and investigated factors associated with good awareness. METHODS: A national cross-sectional study was conducted to recruit adult Palestinian women from hospitals, primary healthcare facilities, and public areas in 11 Palestinian governorates. A translated-into-Arabic version of the Cancer Awareness Measure-Mythical Causes Scale was used to collect data. Awareness level was determined based on the number of CC myths around CC causation recognized to be incorrect: poor (0-4), fair (5-9), and good (10-13). RESULTS: A total of 7058 questionnaires were included. Myths unrelated to food were more commonly recognized as incorrect compared to those related to food. The most recognized food-unrelated myth was 'having a physical trauma' (n = 3714, 52.6%), whereas the least recognized was 'using mobile phones' (n = 2238, 31.7%). The most recognized food-related myth was 'drinking from plastic bottles' (n = 2708, 38.4%), whereas the least recognized was 'eating food containing additives' (n = 1118, 15.8%). Only 575 participants (8.1%) displayed good awareness and promptly recognized at least 10 out of 13 myths around CC causation as incorrect. Factors associated with lower likelihood of displaying good awareness of myths around CC causation included living in the West Bank and Jerusalem, being married, widowed or divorced, knowing someone with cancer, and visiting hospitals or primary healthcare centers. CONCLUSIONS: A very small proportion of Palestinian women recognized 10 or more myths around CC causes as incorrect. Initiatives addressing CC myths are needed in the Palestinian community.

Differences in colorectal cancer awareness between screening eligible vs. ineligible Palestinians: a national cross-sectional study.

BACKGROUND: This study aimed to compare colorectal cancer (CRC) awareness between screening-eligible and ineligible individuals in Palestine. METHODS: Convenience sampling was utilized to recruit Palestinian adults from diverse settings, including hospitals, primary healthcare centers and public spaces across 11 governorates. The evaluation of CRC awareness in terms of signs/symptoms, risk factors and causation myths was conducted using Arabic-translated, modified versions of the validated instruments, the Bowel Cancer Awareness Measure and the Cancer Awareness Measure-Mythical Causes Scale. RESULTS: The final analysis included 2698 participants, with 2158 (80.9%) eligible for CRC screening and 540 (19.1%) ineligible for it. The most recognized CRC sign/symptom was 'lump in the abdomen' in both screening-eligible (n = 386, 71.5%) and ineligible (n = 1582, 73.3%) groups. 'Lack of physical activity' was the most recognized risk factor in both groups (eligible: n = 451, 83.5%; ineligible: n = 1766, 81.8%). The most reported causation myth in both groups was 'having a physical trauma' (eligible: n = 340, 63.0%; ineligible: n = 1353, 62.7%). In the screening-eligible group, only 210 participants (38.9%) demonstrated high awareness of CRC signs/symptoms, 213 participants (39.4%) showed high awareness of CRC risk factors and only 46 participants (8.5%) displayed high awareness of CRC causation myths. There were no significant associations between being eligible for screening colonoscopy and the awareness levels of CRC signs/symptoms, risk factors and causation myths. CONCLUSION: Overall, awareness levels of CRC signs/symptoms, risk factors and causation myths were notably low among screening-eligible participants. There were no differences in awareness levels between individuals eligible for colonoscopy and those who were not.

Mechanosensitive channel gating by delipidation.

The mechanosensitive channel of small conductance (MscS) protects bacteria against hypoosmotic shock. It can sense the tension in the surrounding membrane and releases solutes if the pressure in the cell is getting too high. The membrane contacts MscS at sensor paddles, but lipids also leave the membrane and move along grooves between the paddles to reside as far as 15 Å away from the membrane in hydrophobic pockets. One sensing model suggests that a higher tension pulls lipids from the grooves back to the membrane, which triggers gating. However, it is still unclear to what degree this model accounts for sensing and what contribution the direct interaction of the membrane with the channel has. Here, we show that MscS opens when it is sufficiently delipidated by incubation with the detergent dodecyl-ß-maltoside or the branched detergent lauryl maltose neopentyl glycol. After addition of detergent-solubilized lipids, it closes again. These results support the model that lipid extrusion causes gating: Lipids are slowly removed from the grooves and pockets by the incubation with detergent, which triggers opening. Addition of lipids in micelles allows lipids to migrate back into the pockets, which closes the channel even in the absence of a membrane. Based on the distribution of the aliphatic chains in the open and closed conformation, we propose that during gating, lipids leave the complex on the cytosolic leaflet at the height of highest lateral tension, while on the periplasmic side, lipids flow into gaps, which open between transmembrane helices.

Female cancer survivors: sexual function, psychological distress, and remaining fertility.

PURPOSE: Improved survivorship in cancer patients leads to new challenging issues including potential impairment of quality of life, sexual function, and fertility. The aim of this study was to assess sexual dysfunction (SD) and psychological distress in female cancer survivors who underwent fertility preservation in the past in comparison to reviewed healthy control data from other published studies. Additionally, our focus was on the difference in SD between women with current desire to get pregnant and already completed family planning. METHODS: In this prospective study, 53 female cancer survivors who underwent fertility preservation at time of cancer diagnosis between 2010 and 2020 were invited to a gynecological exam, laboratory assessment, and two questionnaires (Female Sexual Function Index (FSFI) and Hospital anxiety and depression scale (HADS)) in 2022. These scores were compared to results in the literature of healthy controls and depending on anti-Mullerian-hormone (AMH) levels, current desire to have a child, and age. RESULTS: After a mean follow-up time of 70 ± 50 months, SD was detected in 60.4% (n = 32) of the 53 included patients. Normal results regarding HADS-D/anxiety and HADS-D/depression were found in 88.7% and 94.3% of patients, respectively. At time of follow-up, 69.9% (n = 40) regained regular menstrual cycles, 52.6% (n = 20) < 40 years showed a diminished ovarian reserve with AMH levels < 1.1 ng/ml and 28.3% (n = 15) suffered from infertility. CONCLUSION: Female cancer survivors may be at risk for SD. Cancer patients should be informed about possible sexual dysfunction already at the start of cancer treatment and during follow-up. In addition, contraception needs to be addressed if regular cycles occur as more than two-thirds of the women regained regular menstrual cycles.

Anticipated time to seek medical advice for possible ovarian cancer symptoms and perceived barriers to early presentation among Palestinian women: a national cross-sectional study.

BACKGROUND: Several factors contribute to delayed presentation with ovarian cancer (OC) symptoms including poor symptom awareness and barriers to seeking help. This study explored the anticipated time to seek medical advice for possible OC symptoms and its association with OC symptom awareness. In addition, it examined perceived barriers that may delay help-seeking among Palestinian women. METHODS: A cross-sectional study was conducted among adult women (≥ 18 years) recruited from hospitals, primary healthcare centers, and public spaces in 11 Palestinian governorates. A modified version of the OC awareness measure was used to collect data in face-to-face interviews. The questionnaire comprised three sections: sociodemographic details, awareness of 11 OC symptoms and time to seek medical advice, and barriers to early presentation. RESULTS: Of 6095 participants approached, 5618 completed the OCAM (response rate = 92.1%). The proportion of participants who would immediately seek medical advice for a possible OC symptom varied based on the symptom's nature. For OC symptoms with pain, the proportion that reported immediate seeking of medical advice ranged from 7.9% for 'persistent low back pain' to 13.6% for 'persistent pain in the pelvis'. For non-specific potential OC symptoms, the proportion that reported immediate seeking of medical advice ranged from 2.3% for 'feeling full persistently' to 15.8% for 'increased abdominal size on most days'. Good OC symptom awareness was associated with higher likelihood of seeking medical advice within a week from recognizing 10 out of 11 OC symptoms. Emotional barriers were the most common barriers with 'feeling scared' as the most reported barrier (n = 1512, 52.4%). Displaying good OC symptom awareness was associated with a lower likelihood of reporting ≥ 4 emotional barriers (OR = 0.61, 95% CI: 0.38-0.98). CONCLUSION: Participants with good OC symptom awareness were more likely to seek medical advice earlier and to display fewer emotional barriers. Establishing educational interventions to raise OC awareness may help in promoting earlier help-seeking and, thus, facilitate earlier diagnosis and improved prognosis.

Biological Activity In Vitro, Absorption, BBB Penetration, and Tolerability of Nanoformulation of BT44:RET Agonist with Disease-Modifying Potential for the Treatment of Neurodegeneration.

BT44 is a novel, second-generation glial cell line-derived neurotropic factor mimetic with improved biological activity and is a lead compound for the treatment of neurodegenerative disorders. Like many other small molecules, it suffers from intrinsic poor aqueous solubility, posing significant hurdles at various levels for its preclinical development and clinical translation. Herein, we report a poly(2-oxazoline)s (POx)-based BT44 micellar nanoformulation with an ultrahigh drug-loading capacity of 47 wt %. The BT44 nanoformulation was comprehensively characterized by 1H NMR spectroscopy, differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), dynamic light scattering (DLS), and cryo-transmission/scanning electron microscopy (cryo-TEM/SEM). The DSC, XRD, and redispersion studies collectively confirmed that the BT44 formulation can be stored as a lyophilized powder and can be redispersed upon need. The DLS suggested that the redispersed formulation is suitable for parenteral administration (Dh ≈ 70 nm). The cryo-TEM measurements showed the presence of wormlike structures in both the plain polymer and the BT44 formulation. The BT44 formulation retained biological activity in immortalized cells and in cultured dopamine neurons. The micellar nanoformulation of BT44 exhibited improved absorption (after subcutaneous injection) and blood-brain barrier (BBB) penetration, and no acute toxic effects in mice were observed. In conclusion, herein, we have developed an ultrahigh BT44-loaded aqueous injectable nanoformulation, which can be used to pave the way for its preclinical and clinical development for the management of neurodegenerative disorders.

Sexual dysfunction in female and male people with multiple sclerosis: disability, depression and hormonal status matter.

BACKGROUND AND PURPOSE: Sexual dysfunction (SD) in people with multiple sclerosis (pwMS) is common and an often underestimated issue in the care of pwMS. The objective of the study was to evaluate risk factors for SD in pwMS, correlate its prevalence with patient-reported measures (quality of life and physical activity) and analyse its association with hormonal status. METHODS: Sexual dysfunction was determined in 152 pwMS using the Multiple Sclerosis Intimacy and Sexuality Questionnaire 19. A logistical regression model was used to identify independent risk factors for SD. RESULTS: The prevalence of SD in pwMS was 47%. Independent risk factors for the development of SD were ever-smoking (odds ratio [OR] 3.4, p = 0.023), disability as measured by the Expanded Disability Status Scale (OR 2.0, p < 0.001), depression (OR 4.3, p = 0.047) and bladder and bowel dysfunction (OR 8.8, p < 0.001); the use of disease-modifying treatment was associated with a lower risk for SD (OR 0.32, p = 0.043). SD was associated with worse quality of life (Multiple Sclerosis Impact Scale 29: physical score 6.3 vs. 40.0; psychological score 8.3 vs. 33.3; both p < 0.001) and lower physical activity (Baecke questionnaire, p < 0.001). Laboratory analysis revealed significantly higher luteinizing hormone and follicle-stimulating hormone levels and lower 17-beta oestradiol, androstenedione, dehydroepiandrosterone sulfate, oestrone and anti-Mullerian hormone levels in female pwMS with SD. In male pwMS and SD, there was a significant decrease in inhibin B levels. CONCLUSIONS: Our findings highlight the requirement of a holistic approach to SD in MS including physical, neurourological and psychosocial factors. Active screening for SD, especially in patients with disability, depression or bladder and bowel dysfunction, is recommended.

Common myths and misconceptions about breast cancer causation among Palestinian women: a national cross-sectional study.

BACKGROUND: The discussion about breast cancer (BC) causation continues to be surrounded by a number of myths and misbeliefs. If efforts are misdirected towards reducing risk from false mythical causes, individuals might be less likely to consider and adopt risk-reducing behaviors for evidence-based BC causes. This national study aimed to assess the awareness of BC causation myths and misbeliefs among Palestinian women, and examine the factors associated with having good awareness. METHODS: This national cross-sectional study recruited adult women from government hospitals, primary healthcare centers, and public spaces in 11 governorates in Palestine. A modified version of the Cancer Awareness Measure-Mythical Causes Scale was used to collect data. The level of awareness of BC causation myths was determined based on the number of myths recognized to be incorrect: poor (0-5), fair (6-10), or good (11-15). RESULTS: A total of 5,257 questionnaires were included. Only 269 participants (5.1%) demonstrated good awareness (i.e., recognizing more than 10 out of 15 BC mythical causes). There were no notable differences in displaying good awareness between the main areas of Palestine, the Gaza Strip and the West Bank and Jerusalem (5.1% vs. 5.1%). Having chronic disease as well as visiting hospitals and primary healthcare centers were associated with a decrease in the likelihood of displaying good awareness. Myths related to food were less frequently recognized as incorrect than food-unrelated myths. 'Eating burnt food' was the most recognized food-related myth (n = 1414, 26.9%), while 'eating food containing additives' was the least recognized (n = 599, 11.4%). 'Having a physical trauma' was the most recognized food-unrelated myth (n = 2795, 53.2%), whereas the least recognized was 'wearing tight bra' (n = 1018, 19.4%). CONCLUSIONS: A very small proportion of Palestinian women could recognize 10 or more myths around BC causation. There is a substantial need to include clear information about BC causation in future educational interventions besides focusing on BC screening, signs and symptoms, and risk factors.

The MscS-like channel YnaI has a gating mechanism based on flexible pore helices.

The mechanosensitive channel of small conductance (MscS) is the prototype of an evolutionarily diversified large family that fine-tunes osmoregulation but is likely to fulfill additional functions. Escherichia coli has six osmoprotective paralogs with different numbers of transmembrane helices. These helices are important for gating and sensing in MscS but the role of the additional helices in the paralogs is not understood. The medium-sized channel YnaI was extracted and delivered in native nanodiscs in closed-like and open-like conformations using the copolymer diisobutylene/maleic acid (DIBMA) for structural studies. Here we show by electron cryomicroscopy that YnaI has an extended sensor paddle that during gating relocates relative to the pore concomitant with bending of a GGxGG motif in the pore helices. YnaI is the only one of the six paralogs that has this GGxGG motif allowing the sensor paddle to move outward. Access to the pore is through a vestibule on the cytosolic side that is fenestrated by side portals. In YnaI, these portals are obstructed by aromatic side chains but are still fully hydrated and thus support conductance. For comparison with large-sized channels, we determined the structure of YbiO, which showed larger portals and a wider pore with no GGxGG motif. Further in silico comparison of MscS, YnaI, and YbiO highlighted differences in the hydrophobicity and wettability of their pores and vestibule interiors. Thus, MscS-like channels of different sizes have a common core architecture but show different gating mechanisms and fine-tuned conductive properties.

Clinical audit as a quality improvement tool in the Gaza Strip: an audit of audits.

BACKGROUND: Clinical audit plays a fundamental role in improving the quality of patient care and hence, is considered a cornerstone of clinical governance. This quality improvement tool is newly introduced in the health-care system of the Gaza Strip. Although the number of audits completed in Gaza has been increasing over the past few years, little evidence is available of subsequent quality improvements in practice. METHODS: An online survey was used to collect information on the audit team, location, applied methods, outcomes, presentation of data, and reaudit. Medical students and health-care professionals who had conducted audits between 2015 and 2018 were invited to complete the survey from Oct 12 to Nov 2, 2018. FINDINGS: Data on 62 audits were collected. Training in clinical governance was received by 55 auditors (89%) and a senior supervisor was available in 56 audits (90%). Audits were performed across different hospitals and specialties: 18 (29%) in obstetrics, 16 (26%) in medicine, and 11 (18%) in each of surgery and paediatrics, with six (10%) in other specialties. A clear trend of increasing numbers of audits was observed, with four (6%) having been done in 2015, 12 (19%) in 2016, 22 (35%) in 2017, and 24 audits (39%) in 2018. Students were involved in 46 audits (74%) whereas practising doctors were involved in only 29 audits (47%). 17 (27.4%) audits were done at more than one health-care facility and the remaining audits were done at one of 13 other main hospitals or community centres across the Gaza Strip. Clear standards were identified in 54 audits (90%) while eight audits (13%) reported not setting standards at all. Improvement of documentation was recommended in 44 audits (71%), development of national guidelines in 37 (60%), and staff training in 32 (52%). Only 32 audits (51.6%) were presented to the local staff. The audit cycle was completed in 13 projects (20.9%) with only seven of them reporting subsequent improvements in practice. INTERPRETATION: A rise in the numbers of audits reflects a growing awareness of their key role in health care and patients' safety. However, completion of audit cycles and the actual implementation of recommendations are lagging. Therefore, more focused efforts supported by both clinical and administrative leaderships are needed to implement changes and ensure continuous evaluation of their effectiveness. FUNDING: None.

Clinical and pathological characteristics and hormone receptor status of women with breast cancer in the European Gaza Hospital: a retrospective chart-based review.

BACKGROUND: Breast cancer is the most common cancer (accounting for 31·3% of all cancers) among women in the Gaza Strip. This audit examines clinical and pathological characteristics of women presenting with breast carcinoma to the European Gaza Hospital (EGH), a governmental hospital and oncological centre serving 600 000 people in the southern Gaza Strip. METHODS: Data were collected from the records of patients with breast cancer treated at the EGH from March, 2015, to Sept, 2017. 397 cases were identified, including 218 patients with full hormone receptor status (oestrogen, progesterone, and Her2/neu receptor status). Data were analysed using Student's t test. FINDINGS: The mean age was 54 years (SD 11·2). 64% of the women (139 of 218) were older than 50 years, and 16% (33 of 218) were younger than 40 years. Histological grade was assessed for 56% of the women (122 of 218), and 55% of these women (67 of 122) presented with grade II tumours. Tumour size was documented in 82% of the files (178 of 218), and tumours were 2-5 cm in 47% of the documented cases (83 of 178). Furthermore, 51% of women (112 of 218) tested positive for the presence of cancer cells in lymph nodes, and 6% (14 of 218) had distant metastasis at presentation. The clinical stage at diagnosis was recorded in 56% of cases (122 of 218), of whom 4% (five of 122) presented at stage I, 54% (66 of 122) presented at stage II, and 42% (51 of 122) presented at stage III/IV. Pre-operative histopathology was carried out for 120 women, of whom 85% (102 of 120) had intraductal carcinoma. Only 81% of women (177 of 218) had post-operative histopathology, of whom 79% (139 of 177) had intraductal carcinoma. The histopathological type was significantly different for pre-operative and post-operative specimens (p<0·0001). Oestrogen receptor status was positive in 58% of patients (127 of 218), progesterone receptor status was positive in 57% of patients (124), and HER2/neu receptor was overexpressed in 33% of patients (65). Triple-negative breast cancer (testing negative for oestrogen, progesterone, and HER2/neu) was found in 23% of the women (49) and double-negative breast cancer (testing negative for oestrogen and progesterone but positive for HER2) in 11% of the women (24). INTERPRETATION: Patients with breast cancer present with advanced disease in the Gaza Strip. HER2/neu overexpression was approximately 10% higher than the percentages reported in the literature for the USA. The significant difference between pre-operative and post-operative specimens' histopathological type could be due to use of fine-needle aspiration. Guidance from the Royal College of Radiologists recommends pre-operative core biopsy. It should be noted that documentation in the patient medical files was incomplete, which is a common obstacle in Gaza that must be tackled for effective improvement in the quality of care. FUNDING: None.