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SARS-CoV-2 is a novel coronavirus which has caused the COVID-19 pandemic. Other known coronaviruses show a strong pattern of seasonality, with the infection cases in humans being more prominent in winter. Although several plausible origins of such seasonal variability have been proposed, its mechanism is unclear. SARS-CoV-2 is transmitted via airborne droplets ejected from the upper respiratory tract of the infected individuals. It has been reported that SARS-CoV-2 can remain infectious for hours on surfaces. As such, the stability of viral particles both in liquid droplets as well as dried on surfaces is essential for infectivity. Here we have used atomic force microscopy to examine the structural stability of individual SARS-CoV-2 virus like particles at different temperatures. We demonstrate that even a mild temperature increase, commensurate with what is common for summer warming, leads to dramatic disruption of viral structural stability, especially when the heat is applied in the dry state. This is consistent with other existing non-mechanistic studies of viral infectivity, provides a single particle perspective on viral seasonality, and strengthens the case for a resurgence of COVID-19 in winter. Statement of Scientific SignificanceThe economic and public health impact of the COVID-19 pandemic are very significant. However scientific information needed to underpin policy decisions are limited partly due to novelty of the SARS-CoV-2 pathogen. There is therefore an urgent need for mechanistic studies of both COVID-19 disease and the SARS-CoV-2 virus. We show that individual virus particles suffer structural destabilization at relatively mild but elevated temperatures. Our nanoscale results are consistent with recent observations at larger scales. Our work strengthens the case for COVID-19 resurgence in winter.
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SARS-CoV-2 virus is the causative agent of COVID-19. Here we demonstrate that non-infectious SARS-CoV-2 virus like particles (VLPs) can be assembled by co-expressing the viral proteins S, M and E in mammalian cells. The assembled SARS-CoV-2 VLPs possess S protein spikes on particle exterior, making them ideal for vaccine development. The particles range in shape from spherical to elongated with a characteristic size of 129 {+/-} 32 nm. We further show that SARS-CoV-2 VLPs dried in ambient conditions can retain their structural integrity upon repeated scans with Atomic Force Microscopy up to a peak force of 1 nN.
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@#Introduction: Acinic cell carcinoma (ACC) represents 1-6% of parotid gland neoplasms. Case Report: We report cytomorphological features of two uncommon variants of acinic cell carcinoma. The first case was an eleven-year-old female with a nodular mass in parotid and the FNA smears demonstrated a lymphoepithelial lesion composed of epithelial tumour cells with features of acinar cells in a lymphoid background. The second case was a 62-year-old male with a large parotid mass. The FNA smears revealed presence of extracellular, acellular amyloid-like material with tumour cells arranged in follicles. Discussion: Awareness of cytomorphological features of these unusual variants of acinic cell carcinoma may help to avoid diagnostic pitfall.
Assuntos
Neoplasias ParotídeasRESUMO
Sepsis is a common cause of death in infants and children. Haemostatic abnormalities have been reported in such patients. There is scant information on the nature and frequency of these abnormalities in children especially from India. Our aim was to evaluate the nature and frequency of haematological and haemostatic abnormalities in children with sepsis. Fifty children between 1-10 years of age admitted with sepsis and 50 age-matched, healthy controls were included in the study. Complete blood counts, examination of stained peripheral blood film, prothrombin time (PT), activated partial thromboplastin time (APTT), plasma fibrinogen, C-reactive protein, liver function tests and serum creatinine were done in all patients and controls. Prolonged PT and APTT were seen in 9 (18%) and 24 (48%) patients respectively. Plasma fibrinogen was decreased in 6% and increased in 8% patients. One or more haemostatic parameter was abnormal in 35 (70%) patients and in all patients who died.
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PURPOSE: To compare Ki-67 index and microvessel density MVD) in multiple myeloma and non-myeloma patients and their correlation with each other and other prognostic markers. MATERIALS AND METHODS: Forty patients were enrolled in this study between 2011-2013, 30 with multiple myelomas and 10 with non-malignant disease as controls. Proliferative activity was analyzed by Ki-67 and microvessel density (MVC) was assessed by CD34 and compared between two groups. In myeloma patients, correlation between Ki-67, MVD and other prognostic factors was assessed by Pearson correlation coefficient. RESULTS: According to Durie Salmon staging criteria, 13 patients were of stage 1, 5 of stage II and 12 of stage III. Ki-67 expression showed a positive correlation with MVD (r=0.729, <0.001) and was significantly higher (<0.0001) in myeloma patients (range 35-80%, mean 60.1 %) as compared to controls (range 8-25%, mean 18.1%). MVD/mm2 was also significantly (<0.0001) higher in myeloma patients (range 62-237/mm2, mean 178.0/mm2) than controls (range 5.2-50/mm2, mean 18.3/mm2). Ki-67 and MVD, both increased progressively with increasing stage of myeloma. Ki-67 showed significant positive correlation with blood urea and lactate dehydrogenase and a significant negative correlation with serum albumin. MVD showed a significant positive correlation with blood urea, lactate dehydrogenase, serum creatinine, ß2 microglobulin and skeletal lesions. CONCLUSIONS: Ki-67 and MVD are indicators of aggressiveness and poor prognosis having significant correlation with each other and other prognostic markers of multiple myeloma. Routine assessment of these markers may help to identify high risk patients, who may benefit from with more aggressive therapy.
