A Rare Case of P63-Negative Sinonasal Nut Midline Carcinoma in the Elderly.

A nuclear protein in testis (NUT) midline carcinoma arises from squamous cells and is often located in the head, neck, and lungs. This report focuses on the negative p63 mutation and older age at the diagnosis of a NUT carcinoma, which has significant prognostic implications. A 62-year-old patient presented initially with a three-year history of recurring frontal headaches, intermittent nasal bleeding, and a sensation of a nasal cavity mass. An incisional biopsy revealed a poorly differentiated NUT carcinoma in the left maxillary sinus. A functional endoscopic sinus surgery was performed, but the cancer recurred. As a result, a total maxillectomy was performed, and the patient was declared cancer-free with no evidence of residual disease. This is a rare instance of a p63-negative midline NUT cell carcinoma (NCC) in an elderly patient, which could potentially contribute to a more favourable prognosis and longer survival compared to other reported cases. LEARNING POINTS: Molecular analysis of a NUT carcinoma and age at diagnosis may serve as a potential means for predicting patient prognosis in cases of midline NCC.Each patient should receive careful monitoring and a personalised treatment strategy based on their molecular studies. Surgical resection, along with a combination of radiotherapy and chemotherapy, has the potential to improve overall survival rates.In line with the commonly observed relationship between increased p63 mutation and poorer survival rates, a negative p63 expression in squamous cell carcinomas may indicate a more favorable prognosis. This hypothesis highlights the importance of further research to validate these findings.

Factors affecting knowledge and attitude of healthcare workers towards basic life support in Khyber Teaching Hospital, Peshawar, Pakistan: a cross-sectional analysis.

OBJECTIVE: This study was conducted to assess the knowledge and attitude of healthcare workers towards basic life support (BLS) in Khyber Teaching Hospital, Peshawar, and to investigate the factors affecting them. DESIGN: Cross-sectional study. SETTING: This study was carried out in a tertiary care hospital in Peshawar, Pakistan. PARTICIPANTS: 201 healthcare professionals were recruited for this study through simple convenience sampling which included house officers (HOs), trained medical officers, postgraduate residents, professors, specialty registrars and nurses. Healthcare professionals who were reluctant to give consent were excluded from the study. RESULTS: Among the chosen participants, only 16.4% had good knowledge whereas 63% had a good attitude towards BLS. Knowledge of participants was found to be positively associated with less time elapsed between the training sessions (p=0.041). On the other hand, factors such as age(p=0.004), designation (p=0.05), number of BLS sessions attended (p=0.012) and the time elapsed since the last BLS session attended (p=0.015), were positively associated with the attitude of healthcare professionals. CONCLUSION: The level of knowledge and attitude towards BLS by healthcare professionals was suboptimal. Those individuals who had attended BLS training sessions frequently had better knowledge and attitude as compared with their counterparts.

`Cryo-EM': electron cryomicroscopy, cryo electron microscopy or something else?

Structural biology continues to benefit from an expanding toolkit, which is helping to gain unprecedented insight into the assembly and organization of multi-protein machineries, enzyme mechanisms and ligand/inhibitor binding. During the last ten years, cryoEM has become widely available and has provided a major boost to structure determination of membrane proteins and large multi-protein complexes. Many of the structures have now been made available at resolutions around 2 Å, where fundamental questions regarding enzyme mechanisms can be addressed. Over the years, the abbreviation cryoEM has been understood to stand for different things. We wish the wider community to engage and clarify the definition of cryoEM so that the expanding literature involving cryoEM is unified.

The active form of quinol-dependent nitric oxide reductase from Neisseria meningitidis is a dimer.

Neisseria meningitidis is carried by nearly a billion humans, causing developmental impairment and over 100 000 deaths a year. A quinol-dependent nitric oxide reductase (qNOR) plays a critical role in the survival of the bacterium in the human host. X-ray crystallographic analyses of qNOR, including that from N. meningitidis (NmqNOR) reported here at 3.15 Šresolution, show monomeric assemblies, despite the more active dimeric sample being used for crystallization. Cryo-electron microscopic analysis of the same chromatographic fraction of NmqNOR, however, revealed a dimeric assembly at 3.06 Šresolution. It is shown that zinc (which is used in crystallization) binding near the dimer-stabilizing TMII region contributes to the disruption of the dimer. A similar destabilization is observed in the monomeric (∼85 kDa) cryo-EM structure of a mutant (Glu494Ala) qNOR from the opportunistic pathogen Alcaligenes (Achromobacter) xylosoxidans, which primarily migrates as a monomer. The monomer-dimer transition of qNORs seen in the cryo-EM and crystallographic structures has wider implications for structural studies of multimeric membrane proteins. X-ray crystallographic and cryo-EM structural analyses have been performed on the same chromatographic fraction of NmqNOR to high resolution. This represents one of the first examples in which the two approaches have been used to reveal a monomeric assembly in crystallo and a dimeric assembly in vitrified cryo-EM grids. A number of factors have been identified that may trigger the destabilization of helices that are necessary to preserve the integrity of the dimer. These include zinc binding near the entry of the putative proton-transfer channel and the preservation of the conformational integrity of the active site. The mutation near the active site results in disruption of the active site, causing an additional destabilization of helices (TMIX and TMX) that flank the proton-transfer channel helices, creating an inert monomeric enzyme.

Impact and influence of crystallography across the sciences.

Crystallography has influenced many of the traditional science disciplines and has opened a number of cross-disciplinary activities often bringing physicists, chemists, biologists and medical scientists together.

Sub-atomic resolution X-ray crystallography and neutron crystallography: promise, challenges and potential.

The International Year of Crystallography saw the number of macromolecular structures deposited in the Protein Data Bank cross the 100000 mark, with more than 90000 of these provided by X-ray crystallography. The number of X-ray structures determined to sub-atomic resolution (i.e. ≤1 Å) has passed 600 and this is likely to continue to grow rapidly with diffraction-limited synchrotron radiation sources such as MAX-IV (Sweden) and Sirius (Brazil) under construction. A dozen X-ray structures have been deposited to ultra-high resolution (i.e. ≤0.7 Å), for which precise electron density can be exploited to obtain charge density and provide information on the bonding character of catalytic or electron transfer sites. Although the development of neutron macromolecular crystallography over the years has been far less pronounced, and its application much less widespread, the availability of new and improved instrumentation, combined with dedicated deuteration facilities, are beginning to transform the field. Of the 83 macromolecular structures deposited with neutron diffraction data, more than half (49/83, 59%) were released since 2010. Sub-mm(3) crystals are now regularly being used for data collection, structures have been determined to atomic resolution for a few small proteins, and much larger unit-cell systems (cell edges >100 Å) are being successfully studied. While some details relating to H-atom positions are tractable with X-ray crystallography at sub-atomic resolution, the mobility of certain H atoms precludes them from being located. In addition, highly polarized H atoms and protons (H(+)) remain invisible with X-rays. Moreover, the majority of X-ray structures are determined from cryo-cooled crystals at 100 K, and, although radiation damage can be strongly controlled, especially since the advent of shutterless fast detectors, and by using limited doses and crystal translation at micro-focus beams, radiation damage can still take place. Neutron crystallography therefore remains the only approach where diffraction data can be collected at room temperature without radiation damage issues and the only approach to locate mobile or highly polarized H atoms and protons. Here a review of the current status of sub-atomic X-ray and neutron macromolecular crystallography is given and future prospects for combined approaches are outlined. New results from two metalloproteins, copper nitrite reductase and cytochrome c', are also included, which illustrate the type of information that can be obtained from sub-atomic-resolution (∼0.8 Å) X-ray structures, while also highlighting the need for complementary neutron studies that can provide details of H atoms not provided by X-ray crystallography.

Metallogenomics and biological X-ray absorption spectroscopy.

An overview of the second special issue of the journal on biological applications of X-ray absorption spectroscopy (BioXAS) is presented. The emphasis is on the study of metalloproteins in the context of structural genomics programmes (metallogenomics).