South African experience with cross-linked ultrahigh molecular weight polyethylene in total hip arthroplasty

Ph.D.,Dept. of Orthopaedic Surgery, Faculty of Health Sciences, University of the Witwatersrand, 2009.Total hip replacement (THR) is an effective method of treatment for patients with hip disability. The procedure is capable of providing long-term functional improvement with excellent control of pain and restoration of function. Sir J Charnley developed a concept of low friction arthroplasty, which was based on use of ultra-high molecular weight polyethylene acetabular and stainless steel femoral components. The components were attached to bone with the use of polymethylmethacrylate (PMMA) bone cement. This concept has been very successful, and is considered the gold standard of THR. Aseptic loosening of the prosthetic components remains the single most important reason for failure of THRs. Wear to the ultra high molecular weight polyethylene (UHMWPE) acetabular cup is a well-known cause of osteolysis and aseptic loosening of the components. Thus, substantial improvement to the wear resistance of UHMWPE could extend the clinical life span of total hip replacements. In an attempt to reduce polyethylene wear and subsequent osteolysis, a method was developed in the early seventies in South Africa to improve polyethylene quality by means of gamma ray cross-linking. The acetabular cup was irradiated with 100 Kilogray in an acetylene environment, which was used as a cross-linking gas material, resulting in improvement of UHMWPE wear resistance. Influenced by the world trend and with the advent of a ceramic bearing surface, the Project of cross-linking was, to a certain extent, forgotten. Patients followed up in the late 1990s, showed minimal or total absence of wear after 15 years or longer. 3 Based on my preliminary studies, and anticipating the world trend of acceptance of cross- link UHMWPE, the aim of this research is to consolidate the results from the largest long term group of patients with acetylene cross-link UHMWPE, to study polyethylene gamma irradiated in the presence of a cross-linking acetiylene gas and the effects of it, in vitro, using a hip simulator. I was planning to communicate with as many patients as possible from the group operated on from 1977 until 1983 in whom cross-link UHMWPE was used. This group of over thousand patients represents the largest group of patients with cross-linked UHMWPE acetabular components in the world, with the longest clinical follow up of over 20 years on average. The first part of the research is a retrospective study: The goal was to contact as many patients as possible who were operated on during the period 1977 to 1983 when cross-linked polyethylene was used. To qualified for the study each patient had to have an early postoperative and the latest follow up radiograph. The radiological study consisted of the radiological measurement of wear. For this purpose the Hip Analysis Suite program was used. This is a software program designed by Dr John M. Martell from the University of Chicago, which is widely used and internationally accepted for that purpose. Image analysis offers significant improvements in reproducibility and accuracy when compared to manual analysis. 4 The final results were compared with results of polyethylene wear in patients in whom conventional UHMWPE was used. For this comparison only patients with acetabular components made from the same UHMWPE material and from the same supplier were used. The conventional UHMWPE is a component of the gold standard of hip replacement surgery. World-wide published follow up studies of 15 years and longer using conventional UHMWPE were compared to the cross-link UHMWPE group. If revision surgery was indicated for whatever reason in patients in with cross-linked UHMWPE acetabular components, the retrieved prosthesis was analyzed. The analysis consisted of examination of the articular surface of the cross-linked acetabular component for micro wear phenomena using a Scanning Electron Microscope (SEM). In order to perform an objective analysis of the retrieved components, two independent laboratories were used, namely: Peterson Tribology Laboratory, Loma Linda University, California, and Biomechanical Laboratory, Faculty of Engineering, University of Pretoria. The analyses were possible thanks to collaboration with Dr Ian Clark from Peterson Tribology Laboratory and Dr NDL Burger in charge of the Biomechanical Laboratory at the Department of Engineering, University of Pretori

Predstavnici pantljičara (cestoda) riba beogradskog sektora Dunava

U radu su izneti rezultati dvogodišnjih istraživanja unutrašnjih parazita različitih vrsta riba Dunava u beogradskom sektoru, i u tom cilju je urađena identifikacija i prikazan je spisak crevnih parazita iz grupe pantljičare (Cestoda). Tokom istraživanja pregledene su ukupno 802 jedinke 22 vrste riba. Pregledom crevnog trakta riba, utvrđeno je da je parazitima zaraženo 140 jedinki 12 vrsta riba, odnosno 17.46%. U inficiranim jedinkama riba nađena su ukupno 13 crevna parazita koji pripadaju grupi Cestoda (pantljičare). Predstavljen je spisak vrsta faune crevnih panljičara, po vrsti ribe, međusobni odnos parazitskih vrsta, kao i njihova dinamika prisustva u jedinkama riba. Prikazane su vrednosti intenziteta (broj parazita po ribi) i ekstenziteta infekcije (% zaraženosti, broj zaraženih riba određenim parazitom). Pantljičare su pljosnati, dorzo-ventralno spljošteni crvi, bez crevnog trakta. Telo im je podeljeno na članke (proglotise). Prednji kraj tela je skoleks i na njemu su smešteni organi za pričvršćivanje (pijavke, kukice). Iza njega je suženje (vratni region), a zatim sledi niz proglotisa. Razviće ovih parazita odvija se kroz smenu generacija (prelazni domaćin je oligoheta). Tokom istraživanja, izdvojile su se određene parazitske vrste pantljičara (“hit paraziti”), koje inficiraju veliki broj vrsta riba. To su vrste Proteocephalus torulosus (7 vrsta riba), Caryophyllaeides fennica i Caryophyllaeus laticeps (6 vrsta riba). Vrsta ribe koja je inficirana sa najvećim brojem parazita je Abramis brama (12). U njenom crevu je identifikovana vrsta parazitske pantljičare sa najvišim intenzitetom infekcije - Caryophyllaeus laticeps (1-165). Istraživana ihtiozajednica beogradskog sektora Dunava još uvek ima sastav koja se može okarakterisati autohtonom, uz napomenu da u toj fauni, nakon izgradnje HEPS „Đerdap“, nema više anadromnih jeseterskih vrsta (Acipenseridae). U zajednici se zapaža izrazita dominacija mirnih riba, pre svega krupatice (Bllica bjoerkna), bodorke (Rutilus rutilus) i deverike (Abramis brama). Većina konstantovanih vrsta riba mogu se smatrati predstavnicima zajednice gornjeg potamona, sa pojedinim elementima – vrstama riba zajednice donjeg ritrona. Sprovedena studija je pokazala da je inficiranost riba Dunava u beogradskom regionu značajna, s obzirom na brojnost i raznovrsnost identifikovanih crevnih parazita grupe pantljičara. Podaci o konstatovanoj fauni crevnih pantljičara upotpunjuju i potvrđuju dosadašnja sporadična saznanja o njihovom rasprostranjenju u otvorenim vodama Srbije. Do sada je, u 75 godišnjim izučavanjima parazitofaune riba površinskih voda Srbije, nađeno ukupno 170 parazita (ekto- i endo-). Od toga, grupi pantljičara (Cestoda) pripada 19 taksona

Spatio-temporal differences in the history of health and noise complaints about Australian wind farms: evidence for the psychogenic, “communicated disease” hypothesis.

Background and objectives With often florid allegations about health problems arising from wind turbine exposure now widespread in parts of rural Australia and on the internet, nocebo effects potentially confound any future investigation of turbine health impact. Historical audits of health complaints across periods when such claims were rare are therefore important. We test 4 hypotheses relevant to psychogenic explanations of the variable timing and distribution of health and noise complaints about wind farms in Australia. Setting All (n=51) Australian wind farms (with 1634 turbines) operating from 1993–2012 . Methods Records of complaints about noise or health obtained from wind farm companies regarding residents living near 51 Australian wind farms, expressed as proportions of estimated populations residing within 5km of wind farms, and corroborated with complaints in submissions to 3 government public enquiries and news media records and court affidavits . Results There are large spatio-temporal variations in wind farm noise and health complaints.33/51(64.7%) of Australian wind farms including 17/34(50%) with turbine size >1MW have never been subject to noise or health complaints. These 33 farms have some 21,592 residents within 5km of their turbines and have operated complaint-free for a cumulative total of 267 years. Western Australia and Tasmania Have seen no complaints. Only 131 individuals across Australia representing approximately 1 in 250 residents living within 5km of wind farms appear to have ever complained, with 94(72%) of these being residents near 6 wind farms which have been targeted by anti wind farm groups . About 1 in 87 (126/10901) of those living near turbines >1MW have ever complained. The large majority 104/131(79%) of health and noise complaints commenced after 2009 when anti wind farm groups began to add health concerns to their wider opposition. In the preceding years, health or noise complaints were rare despite large and small turbined wind farms having operated for many years. Conclusions In view of scientific consensus that the evidence for wind turbine noise and infrasound causing health problems is poor, the reported spatio-temporal variations in complaints are consistent with psychogenic hypotheses that health problems arising are “communicated diseases” with nocebo effects likely to play an important role in the aetiology of complaints

Paraziti crevnog trakta deverike abramis brama (linnaeus, 1758) Dunava u beogradskom delu toka

Izučavanje parazitofaune riba prirodnih voda od izuzetnog je značaja, ne samo u naučnom pogledu, već i za njihov uspešan intenzivan način gajenja u akvakulturi. U radu su predstavljeni rezultati istraživanja crevnih parazitskih vrsta deverike Abramis brama L. 1758. Primerci riba su sakupljeni tokom perida 2007–2009 na dva lokaliteta uzorkovanja duž toka reke Dunav koji protiče kroz beogradski region. Ukupno je pregledano 177 jedinki deverike različite starosti (2+ to 6+). Prtisustvo crevnih parazitskih vrsta identifikovano je kod 97 pregledanih primeraka deverike, sa intenzitetom infekcije u rasponu 1–165, predstavljajući 54.80% od ukupnog broja sakupljenih i pregledanih primeraka riba. U inficiranim jedinkama deverike utvrđeno je prisustvo 27 taksona endoparazita (helminta) iz četiri klase: jedanaest vrsta pantljičara (Cestoda), pet vrsta i jedan takson metilja (Trematoda), dve vrste klase Nematoda i osam vrsta Acanthocephala. Sprovedena istraživanja su pokazala da je inficiranost deverike Dunava u beogradskom regionu značajna, s obzirom na brojnost i raznovrsnost identifikovanih crevnih parazita. Buduća istraživanja su neophodna da bi se utvrdila uloga crevnih parazita u regulisanju brojnosti populacija deverike Dunava

Direct anterior approach in total hip arthroplasty: a narrative review

Objective: Worldwide, a growing number of Total Hip Arthroplasty (THA) procedures are being performed each year. However, despite this significant global demand, the ideal surgical approach remains controversial. Globally there has been a significant increase in the use of direct anterior approach THA. Therefore, the objective of this paper was to synthesise the vast body of new, evolving information into one non-biased narrative review, to provide an overarching review of various aspects of this approach, including controversial issues such as, benefits, functional outcomes, complications, costs, and surgical technique. Data source: The following keywords were entered into various scientific databases including, Mbase, Google scholar and PubMed. Only articles published in journals between 2017 and 2021 were extracted and included in this review. We found 148 articles published during this period and we used the 82 most relevant articles to collate this narrative review. Data selection/ extraction: Three fellowship trained arthroplasty orthopaedic surgeons, (JRTP, LM and JC) went through all the papers and selected the 82 most relevant papers for inclusion in this review. Conclusion: There has been significant interest and renewed vaguer in publication rates by authors worldwide evaluating the use of the DAA in THA. Most recent studies show that there is increasing evidence that the DAA is a safe, reliable, and reproducible surgical approach to THA. Direct anterior approach provides, in the most part, superior early short term functional outcomes in comparison with other THA approaches. It has however also been shown that a steep learning curve exists when using this approach. While complication rates are similar to those seen in other approaches, the types of complications however remain slightly different with an increase incidence of intraoperative peri-prosthetic femoral fractures, wound complications and femoral stem aseptic loosening being significantly greater in the direct anterior approach

Sericicultura: hilo de posibilidades

El trabajo muestra una forma simple de separación de las proteínas sericina y fibroina del capullo de seda de los insectos lepidópteros Bombix mori, luego de completar su metamorfosis, así como posibles usos de estas proteínas. El método utilizado para separar las proteínas es el de “desgomado”; con la sericina, se confecciona una crema para manos y con la fibroina se confeccionó un soporte inductor en el crecimiento de semillas de canola en hidroponía estéril. La crema resulta tener gran capacidad humectante e hidratante, mientras que se comprobó que la fibroina usada como soporte propicia una germinación rápida de las semillas de canola

Synthesis and characterisation of bismacrocyclic DO3A-amide derivatives – an approach towards metal-responsive PARACEST agents

[Abstract] Three new bismacrocyclic Ln3+ chelates consisting of triamide derivatives of cyclen with glycine, methyl and tert-butyl substituents (L1–3, respectively) linked to an acyclic EGTA-derived calcium chelator were synthesised as potential MRI contrast agents (EGTA – ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid). Eu3+ and Yb3+ complexes of L1–3 were investigated as chemical exchange saturation transfer (CEST) agents. Moderate to minor CEST effects were observed for Eu2L1, Eu2L2 and Yb2L2 complexes in the absence of Ca2+, with negligible changes upon addition of this metal ion. Luminescence steady-state emission and lifetime experiments did not reveal any changes in the coordination environment of the complexes, while the number of inner-sphere water molecules remained constant in the absence and presence of Ca2+. The protonation constants of Eu2L1 and Eu2L2 and stability constants of their complexes with Ca2+, Mg2+ and Zn2+ were determined by means of potentiometric titrations. The results show that the charge of the complex dramatically affects the protonation constants of the EGTA-binding unit. The stability constants of the complexes formed with Ca2+, Mg2+ and Zn2+ are several orders of magnitude lower than those of EGTA. These findings indicate that the nature of Ln3+ chelates and their charge are the main reasons for the observed results and weaker response of these EGTA-derived triamide derivatives compared to their tricarboxylate analogues

Freshwater jellyfish craspedacusta sowerbyi lankester, 1880 (hydrozoa, olindiidae)-50 years' observations in Serbia

Detailed and relevant limnological investigations of Serbian waters were initiated in 1958 and have continued to the present. During the period 1971-2008 we monitored biological elements as a part of working studies/projects, including the distribution of the freshwater jellyfish Craspedacusta sowerbyi Lankester, 1880. We observed over 500 sampling sites in running and standing waters. Specimens of this hydro-medusa were found in five of them. Throughout the period of investigation, only the medusae stages were observed. Our purpose in this paper was to provide data of the records and distribution of this limnomedusa during the period 1958-2008 in inland waters of Serbia. These observations should contribute to knowledge on the limnofauna not only of the Balkan Peninsula but Europe as a whole