A Survey on Various Brain MR Image Segmentation Techniques

Prior to medical image analysis, segmentation is an essential step in the preprocessing process. Partitioning an image into distinct regions based on characteristics like texture, color, and intensity is its primary goal. Numerous applications include tumor and coronary border recognition, surgical planning, tumor volume measurement, blood cell classification and heart image extraction from cardiac cine angiograms are all made possible by this technique. Many segmentation methods have been proposed recently for medical images. Thresholding, region-based, edge-based, clustering-based and fuzzy based methods are the most important segmentation processes in medical image analysis. A variety of image segmentation methods have been developed by researchers for efficient analysis. An overview of widely used image segmentation methods, along with their benefits and drawbacks, is provided in this paper

Usporedna procjena različitih postupaka lančane reakcije polimerazom uz prethodnu reverznu transkripciju za dokaz gena F i N virusa kuge malih preživača u kliničkim uzorcima.

In the present study the diagnostic value of different sets of F and N gene based primers currently used for diagnosis of Peste des petits ruminants (PPR) by reverse transcription polymerase chain reaction (RT-PCR) were assessed by comparing it with Sandwich ELISA (S-ELISA). A total of five primer pairs, consisting of two pairs (F1/F2 and Fb1/Fb2) amplifying two different regions of F gene and three pairs amplifying different regions of N gene (NP3/NP4, pprn_fr2/pprn_rev and N1/N2) were compared on 10 clinical samples (4 blood, 4 nasal swabs and 2 tissue samples) collected from animals suspected for PPR. The primer sets NP3/NP4 detected highest number of positive samples 6 out of 10 followed by N1/N2 (5/10). Both F-gene based primers (F1/ F2 and Fb1/Fb2) detected 3 out of 10 samples as positive. Whereas the primer pair pprn_fr2/pprn_rev did not yield the desired amplicon in any of the samples tested. The maximum sensitivity and specififi city of 100% was observed by NP3 and NP4 primer based RT-PCR whereas, 0% sensitivity was recorded by pprn_fr2/pprn_rev which fail to detect any positive sample. The overall agreement of 100% with kappa value 1.00 was highest between S-ELISA and NP3 and NP4 primer based RT-PCR suggesting an almost perfect agreement, followed by N1/N2, having kappa value of 0.800, suggesting a substantial agreement. Results thus obtained in the present study, suggest that F-gene primers based RT-PCR can be easily replaced by highly sensitive and specific N-gene primers based RT-PCR for detection of PPR virus nucleic acid.Istražena je dijagnostička vrijednost različitih početnica za gene F i N koje se sada rabe za dijagnosticiranje kuge malih preživača lančanom reakcijom polimerazom uz prethodnu reverznu transkripciju u usporedbi sa sendvič imunoenzimnim testom (S-ELISA). Testirano je ukupno pet parova početnica: dva para (F1/F2 i Fb1/Fb2) specifična za različita područja gena F i tri para specifična za različita područja gena N (NP3/NP4, pprn_fr2/pprn_rev i N1/N2). Njihova vrijednost bila je uspoređena pretragom 10 kliničkih uzoraka (četiri uzorka krvi, četiri uzorka nosnog obriska i dva uzorka tkiva) uzetih od životinja pod sumnjom na kugu malih preživača. Uporabom početnica NP3/NP4 dokazan je najveći broj pozitivnih uzoraka (6/10), a potom početnicom N1/N2 (5/10). Objema početnicama za gen F (F1/F2 i Fb1/Fb2) dokazana su tri pozitivna uzorka (3/10). Par početnice pprn_fr2/pprn_rev nije dao željeni umnožak (amplikon) ni u jednom pretraženom uzorku. Osjetljivost i specifičnost od 100% dokazana je za početnice NP3 i NP4, dok pprn_fr2/pprn_rev nisu pokazale nikakvu reakciju te njihovom upotrebom nije dokazan nijedan pozitivan uzorak. Podudarnost od 100% s kappa vrijednošću 1,00 bila je najveća između S-ELISA-e te RT-lančane reakcije polimerazom upotrebom početnica NP3 i NP4 što govori o posvemašnjoj podudarnosti, dok je na drugom mjestu po podudarnosti bila početnica N1/N2 s kappa vrijednošću od 0,800. Rezultati pokazuju da se RT-lančana reakcije polimerazom upotrebom početnica za gen F može zamijeniti vrlo osjetljivom i specifičnom reakcijom uz upotrebu početnica za gen N za dokazivanje nukleinske kiseline virusa kuge malih preživača

Usporedna procjena različitih postupaka lančane reakcije polimerazom uz prethodnu reverznu transkripciju za dokaz gena F i N virusa kuge malih preživača u kliničkim uzorcima.

In the present study the diagnostic value of different sets of F and N gene based primers currently used for diagnosis of Peste des petits ruminants (PPR) by reverse transcription polymerase chain reaction (RT-PCR) were assessed by comparing it with Sandwich ELISA (S-ELISA). A total of five primer pairs, consisting of two pairs (F1/F2 and Fb1/Fb2) amplifying two different regions of F gene and three pairs amplifying different regions of N gene (NP3/NP4, pprn_fr2/pprn_rev and N1/N2) were compared on 10 clinical samples (4 blood, 4 nasal swabs and 2 tissue samples) collected from animals suspected for PPR. The primer sets NP3/NP4 detected highest number of positive samples 6 out of 10 followed by N1/N2 (5/10). Both F-gene based primers (F1/ F2 and Fb1/Fb2) detected 3 out of 10 samples as positive. Whereas the primer pair pprn_fr2/pprn_rev did not yield the desired amplicon in any of the samples tested. The maximum sensitivity and specififi city of 100% was observed by NP3 and NP4 primer based RT-PCR whereas, 0% sensitivity was recorded by pprn_fr2/pprn_rev which fail to detect any positive sample. The overall agreement of 100% with kappa value 1.00 was highest between S-ELISA and NP3 and NP4 primer based RT-PCR suggesting an almost perfect agreement, followed by N1/N2, having kappa value of 0.800, suggesting a substantial agreement. Results thus obtained in the present study, suggest that F-gene primers based RT-PCR can be easily replaced by highly sensitive and specific N-gene primers based RT-PCR for detection of PPR virus nucleic acid.Istražena je dijagnostička vrijednost različitih početnica za gene F i N koje se sada rabe za dijagnosticiranje kuge malih preživača lančanom reakcijom polimerazom uz prethodnu reverznu transkripciju u usporedbi sa sendvič imunoenzimnim testom (S-ELISA). Testirano je ukupno pet parova početnica: dva para (F1/F2 i Fb1/Fb2) specifična za različita područja gena F i tri para specifična za različita područja gena N (NP3/NP4, pprn_fr2/pprn_rev i N1/N2). Njihova vrijednost bila je uspoređena pretragom 10 kliničkih uzoraka (četiri uzorka krvi, četiri uzorka nosnog obriska i dva uzorka tkiva) uzetih od životinja pod sumnjom na kugu malih preživača. Uporabom početnica NP3/NP4 dokazan je najveći broj pozitivnih uzoraka (6/10), a potom početnicom N1/N2 (5/10). Objema početnicama za gen F (F1/F2 i Fb1/Fb2) dokazana su tri pozitivna uzorka (3/10). Par početnice pprn_fr2/pprn_rev nije dao željeni umnožak (amplikon) ni u jednom pretraženom uzorku. Osjetljivost i specifičnost od 100% dokazana je za početnice NP3 i NP4, dok pprn_fr2/pprn_rev nisu pokazale nikakvu reakciju te njihovom upotrebom nije dokazan nijedan pozitivan uzorak. Podudarnost od 100% s kappa vrijednošću 1,00 bila je najveća između S-ELISA-e te RT-lančane reakcije polimerazom upotrebom početnica NP3 i NP4 što govori o posvemašnjoj podudarnosti, dok je na drugom mjestu po podudarnosti bila početnica N1/N2 s kappa vrijednošću od 0,800. Rezultati pokazuju da se RT-lančana reakcije polimerazom upotrebom početnica za gen F može zamijeniti vrlo osjetljivom i specifičnom reakcijom uz upotrebu početnica za gen N za dokazivanje nukleinske kiseline virusa kuge malih preživača

Posterior capsule opacification: What's in the bag?

Cataract, a clouding of the lens, is the most common cause of blindness in the world. It has a marked impact on the wellbeing and productivity of individuals and has a major economic impact on healthcare providers. The only means of treating cataract is by surgical intervention. A modern cataract operation generates a capsular bag, which comprises a proportion of the anterior capsule and the entire posterior capsule. The bag remains in situ, partitions the aqueous and vitreous humours, and in the majority of cases, houses an intraocular lens (IOL). The production of a capsular bag following surgery permits a free passage of light along the visual axis through the transparent intraocular lens and thin acellular posterior capsule. Lens epithelial cells, however, remain attached to the anterior capsule, and in response to surgical trauma initiate a wound-healing response that ultimately leads to light scatter and a reduction in visual quality known as posterior capsule opacification (PCO). There are two commonly-described forms of PCO: fibrotic and regenerative. Fibrotic PCO follows classically defined fibrotic processes, namely hyperproliferation, matrix contraction, matrix deposition and epithelial cell trans-differentiation to a myofibroblast phenotype. Regenerative PCO is defined by lens fibre cell differentiation events that give rise to Soemmerring's ring and Elschnig's pearls and becomes evident at a later stage than the fibrotic form. Both fibrotic and regenerative forms of PCO contribute to a reduction in visual quality in patients. This review will highlight the wealth of tools available for PCO research, provide insight into our current knowledge of PCO and discuss putative management of PCO from IOL design to pharmacological interventions

Posterior capsule opacification after phacoemulsification: Foldable acrylic versus poly(methyl methacrylate) intraocular lenses

Purpose: To study the effects of foldable acrylic and poly(methyl methacrylate) (PMMA) intraocular lens (IOL) implantation on posterior capsule opacification (PCO)