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1.
IEEE Trans Med Imaging ; 42(3): 684-696, 2023 03.
Article in English | MEDLINE | ID: mdl-36227828

ABSTRACT

Registration of dynamic CT image sequences is a crucial preprocessing step for clinical evaluation of multiple physiological determinants in the heart such as global and regional myocardial perfusion. In this work, we present a deformable deep learning-based image registration method for quantitative myocardial perfusion CT examinations, which in contrast to previous approaches, takes into account some unique challenges such as low image quality with less accurate anatomical landmarks, dynamic changes of contrast agent concentration in the heart chambers and tissue, and misalignment caused by cardiac stress, respiration, and patient motion. The introduced method uses a recursive cascade network with a ventricle segmentation module, and a novel loss function that accounts for local contrast changes over time. It was trained and validated on a dataset of n = 118 patients with known or suspected coronary artery disease and/or aortic valve insufficiency. Our results demonstrate that the proposed method is capable of registering dynamic cardiac perfusion sequences by reducing local tissue displacements of the left ventricle (LV), whereas contrast changes do not affect the registration and image quality, in particular the absolute CT (HU) values of the entire CT sequence. In addition, the deep learning-based approach presented reveals a short processing time of a few seconds compared to conventional image registration methods, demonstrating its application potential for quantitative CT myocardial perfusion measurements in daily clinical routine.


Subject(s)
Deep Learning , Myocardial Perfusion Imaging , Humans , Tomography, X-Ray Computed , Myocardium , Heart/diagnostic imaging , Perfusion , Image Processing, Computer-Assisted
2.
Vet Anim Sci ; 17: 100261, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35856003

ABSTRACT

Consultation was requested for a 7-year-old Gypsy Vanner male horse with a 2-year history of foreskin injury. Upon revision, an ulcer, 153 cm2 in size, with yellowish granules was observed; a RESVECH 2.0 evaluation revealed a score of 32/35 points. Medical history confirmed multiple failed deworming, anti-inflammatory, and antibiotic treatments with different topical therapies and recurrence in summer. Laboratory results confirmed elevated total proteins (8.8 g/dL) and globulins (5.5 g/dL), negative bacterial and fungal cultures, as well as negative coproparasitoscopic findings, and finally, identification of stable fly larvae (Stomoxys calcitrans) in the feces. Microscopy showed disorganized collagen, thickened tissue, polymorphonuclear cells, and acanthosis without neoplastic tissue or parasite remains. Debridement was performed and systemic treatment with ivermectin, penicillin, and non-steroidal anti-inflammatory drugs (NSAIDs) continued. In addition, 2% chitosan gel and films were applied to the entire surface of the lesion for 72 hours on 30 occasions; vector control with nets and insecticides was performed. On day 94, there was a 6 cm2 surface with involvement of the dermal and epidermal layers, moist epithelial tissue, and diffuse edges, with a RESVECH 2.0 evaluation of 6/35 points. Microscopy showed an intact basement membrane, presence of hair follicles, sweat glands, aligned collagen, and angiogenesis. It was concluded that chronic skin lesions in horses represent a diagnostic challenge, and topical chitosan is an adequate treatment due to its biocompatibility and efficacy, in addition to the functional and cosmetic results in dermal regeneration.

3.
J Chemother ; 22(3): 160-4, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20566419

ABSTRACT

The production of extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae is the most prevalent resistance mechanism to third-generation cephalosporins. The aim of this study was to identify the ESBLs produced in Escherichia coli and Klebsiella pneumoniae clinical isolates from two hospitals of the Colombian Caribbean Region. A total of 30 clinical isolates of K. pneumoniae (21) and E. coli (9) ESBL-producers were collected in two hospitals from January, 2001 to June, 2003. Isoelectric point values were indicative of SHV-, and CTX-M-type beta-lactamases. PCR amplification and sequencing of SHV genes revealed that SHV-12 was the most prevalent ESBL followed by SHV-5, SHV-2a, the novel SHV-86 and CTX-M-12. There was a geographic distribution of two particular PFGE subtypes in these two distant hospitals. Clonal and horizontal dissemination of resistance was observed.


Subject(s)
Escherichia coli/enzymology , Klebsiella pneumoniae/enzymology , beta-Lactamases/genetics , Caribbean Region , Drug Resistance, Multiple, Bacterial , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Hospitals , Humans , Klebsiella Infections/microbiology , Klebsiella pneumoniae/isolation & purification , Microbial Sensitivity Tests , Polymerase Chain Reaction , beta-Lactamases/metabolism
4.
Antimicrob Agents Chemother ; 39(7): 1621-3, 1995 Jul.
Article in English | MEDLINE | ID: mdl-7492118

ABSTRACT

Spontaneous quinolone-resistant mutants obtained from Salmonella typhimurium Su694 were screened for mutations by direct DNA sequencing of an amplified PCR gyrA fragment. Substitutions Ser-83-->Phe (Ser83Phe), Ser83Tyr, Asp87Tyr, and Asp87Asn and double mutation Ala67Pro-Gly81Ser, which resulted in decreased sensitivities to ciprofloxacin, enoxacin, pefloxacin, norfloxacin, ofloxacin, and nalidixic acid, were found. The levels of resistance to quinolones for each mutant were determined.


Subject(s)
Anti-Infective Agents/pharmacology , DNA Topoisomerases, Type II/genetics , Mutation , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics , Amino Acid Sequence , Base Sequence , DNA Gyrase , DNA, Bacterial/genetics , Drug Resistance, Microbial , Fluoroquinolones , Molecular Sequence Data , Polymerase Chain Reaction , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid
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