Tribocorrosion behavior of CoCrMo alloy for hip prosthesis as a function of loads: A comparison between two testing systems

Metal-on-metal (MOM) hip prosthesis bearings have enjoyed renewed popularity, but concerns remain with wear debris and metal ion release causing a negative response in the surrounding tissues. Further understanding into the wear and corrosion mechanisms occurring in MOM hips is therefore essential. The purpose of this study was to evaluate the tribocorrosion behavior, or interplay between corrosion and wear, of a low-carbon CoCrMo alloy as a function of loading. The tribocorrosion tests were performed using two tribometer configurations. In the first configuration, “System A”, a linearly reciprocating alumina ball slid against the flat metal immersed in a phosphate buffer solution (PBS). In the second configuration, “System B”, the flat end of a cylindrical metal pin was pressed against an alumina ball that oscillated rotationally, using bovine calf serum (BCS) as the lubricant and electrolyte. System B was custom-built to emulate in vivo conditions. The tribocorrosion tests were performed under potentiostatic conditions at −0.345 V, with a sliding duration of 1800 s and a frequency of 1 Hz. In System A the applied loads were 0.05, 0.5, and 1 N (138, 296 and 373 MPa, respectively) and in System B were 16, 32, and 64 N (474, 597, and 752 MPa, respectively). Electrochemical impedance spectroscopy (EIS) and polarization resistance were estimated. The total mass loss (Kwc) in the CoCrMo was determined. The mass loss due to wear (Kw) and that due to corrosion (Kc) were determined. The dominant wear regime for the CoCrMo alloy subjected to sliding changes from wear–corrosion to mechanical wear as the contact stress increases. An attempt was made to compare both system, in their tribochemical responses and formulate some insights in the total degradation processes. Our results also suggest that the proteins in the serum lubricant assist in the generation of a protective layer against corrosion during sliding. The study highlights the need of adequate methodology/guidelines to compare the results from different test systems and translating in solving the practical problems

HEALTHCARE PROCESS OF THE PATIENT WITH ACUTE PANCREATITIS

Akutni pankreatitis je nagla upala gušterače koja se može javiti u blagom ili teškom obliku. Ova nagla upala se u gotovo 80% prijema u bolnicu pripisuje postojanju žučnih kamenaca ili konzumaciji alkohola. Žučni kamenci kao uzrok budu 1,5 puta češći kod žena, dok se alkohol kao uzrok u muškaraca pojavljuje šest puta više nego kod žena. Žučni kamenci najčešće začepe otvor pankreatičnog voda ili se na neko vrijeme zaustave u Oddijevu sfinkteru uzrokujući time upalu dok svakodnevna konzumacija alkohola također može dovesti do začepljenja malih vodova. Jaki bolovi se javljaju najčešće naglo nakon konzumacije prekomjerne količine obroka ili alkohola u gornjem srednjem dijelu abdomena. Osim što je bol nagla, pacijenti je opisuju kao probadajuću bol koja se širi u leđa. Može se javiti mučnina kao i nagon na povraćanje, u većini slučajeva popratnu uz temperaturu. Bolesnik se javlja u hitni trakt radi jakih bolova koji se ne smanjuju te se podvrgava daljnjoj dijagnostici. Laboratorijskim pretragama ne može se potvrditi dijagnoza akutnog pankreatitisa ali povišenom razinom enzima gušterače tu dijagnozu možemo potkrijepiti. Daljnjim radiološkim pretragama (rendgen abdomena, kompjutorizirana tomografija) dokazuje se mogućnost postojanja žučnih kamenaca kao i promjene u veličini i strukturi gušterače. Sa utvrđenom dijagnozom akutnog pankreatitisa, osoba se zaprima na odjel gdje se prekida daljnji unos hrane i pića kako bi se smanjila daljnja proizvodnja enzima u gušterači. Svu potrebnu tekućinu i ostale hranjive tvari nadoknađuju se intravenskim putem. U cijelom procesu liječenja ključna je i medicinska sestra koja najprije može uočiti eventualne promjene koje se mogu javiti kod pacijenta, kao što su primjerice smanjeno mokrenje, otežano disanje te stagniranje ili pogoršavanje intenziteta boli unatoč primijenjenoj analgetskoj terapiji.Acute pancreatitis is a sudden pancreatic inflammation occurring in mild or severe form. This sudden inflammation in almost 80% of admission to the hospital is attributed to the existence of gallstones or drinking alcohol. The gallstones as a cause of Acute pancreatitis are 1.5 times more common in women, while alcohol as a cause is present men appears six times more than in women. Gallstones usually close the pancreatic opening or stop for a while in Oddies sphincter causing it to inflate ,while daily alcohol consumption also leads to clogging of small lines. Strong pain usually are occurring suddnely after eating excessive meals or presence of alcohol in the upper mid-section of the abdomen. Apart pain is acute, patients are describeing as a stabbing kind of pain that is spreading in their back. There can be nausea and vomiting, in most cases accompanied by temperature. The patient is coming to an emergency with severe pain that does not diminish and undergoes further diagnosis. Laboratory examinations can not confirm the diagnosis of acute pancreatitis but elevated pancreatic enzyme levels can be supported by this diagnosis. Further radiological examinations (X-ray abdomena, computerized tomography) are proveing the possibility of gallstones as well as changes in the size and structure of the pancreas. With established diagnosis of acute pancreatitis, a person is hospitalized in intensice care where further food and drink intake is discontinued in order to reduce further enzyme production in the pancreas. All the necessary fluid and other nutrients are compensated by the intravenous. Throughout the process of treatment, role of nurse is also crucial to notice possible changes that may occur in the patient, such as decreased urination, difficulty breathing and stagnation or aggravation of pain intensity despite analgesic therapy

Autoantibodies against type I IFNs in patients with life-threatening COVID-19

Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 of 987 patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-w (IFN-w) (13 patients), against the 13 types of IFN-a (36), or against both (52) at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 of the 101 were men. A B cell autoimmune phenocopy of inborn errors of type I IFN immunity accounts for life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men

Latent class analysis of the Yale-Brown Obsessive-Compulsive Scale symptoms in obsessive-compulsive disorder

Objective: Obsessive-compulsive disorder (OCD) is phenomenologically heterogeneous, and findings of underlying structure classification based on symptom grouping have been ambiguous to date. Variable-centered approaches, primarily factor analysis, have been used to identify homogeneous groups of symptoms; but person-centered latent methods have seen little use. This study was designed to uncover sets of homogeneous groupings within 1611 individuals with OCD based on symptoms. Method: Latent class analysis models using 61 obsessive-compulsive symptoms collected from the Yale-Brown Obsessive-Compulsive Scale were fit. Relationships between latent class membership and treatment response, sex, symptom severity, and comorbid tic disorders were tested for relationship to class membership. Results: Latent class analysis models of best fit yielded 3 classes. Classes differed only in frequency of symptom endorsement. Classes with higher symptom endorsement were associated with earlier age of onset, being male, higher Yale-Brown Obsessive-Compulsive Scale symptom severity scores, and comorbid tic disorders. There were no differences in treatment response between classes. Conclusions: These results provide support for the validity of a single underlying latent OCD construct, in addition to the distinct symptom factors identified previously via factor analyses. © 2011 Elsevier Inc. All rights reserved.Articl