A semi-automatic method for quantification and classification of erythrocytes infected with malaria parasites in microscopic images

Visual quantification of parasitemia in thin blood films is a very tedious, subjective and time-consuming task. This study presents an original method for quantification and classification of erythrocytes in stained thin blood films infected with Plasmodium falciparum. The proposed approach is composed of three main phases: a preprocessing step, which corrects luminance differences. A segmentation step that uses the normalized RGB color space for classifying pixels either as erythrocyte or background followed by an Inclusion-Tree representation that structures the pixel information into objects, from which erythrocytes are found. Finally, a two step classification process identifies infected erythrocytes and differentiates the infection stage, using a trained bank of classifiers. Additionally, user intervention is allowed when the approach cannot make a proper decision. Four hundred fifty malaria images were used for training and evaluating the method. Automatic identification of infected erythrocytes showed a specificity of 99.7% and a sensitivity of 94%. The infection stage was determined with an average sensitivity of 78.8% and average specificity of 91.2%.     

Apoptosis, cell proliferation and modulation of cyclin-dependent kinase inhibitor p21cip1 in vascular remodelling during vein arterialization in the rat

Neo-intima development and atherosclerosis limit long-term vein graft use for revascularization of ischaemic tissues. Using a rat model, which is technically less challenging than smaller rodents, we provide evidence that the temporal morphological, cellular, and key molecular events during vein arterialization resemble the human vein graft adaptation. Right jugular vein was surgically connected to carotid artery and observed up to 90 days. Morphometry demonstrated gradual thickening of the medial layer and important formation of neo-intima with deposition of smooth muscle cells (SMC) in the subendothelial layer from day 7 onwards. Transmission electron microscopy showed that SMCs switch from the contractile to synthetic phenotype on day 3 and new elastic lamellae formation occurs from day 7 onwards. Apoptosis markedly increased on day 1, while α-actin immunostaining for SMC almost disappeared by day 3. On day 7, cell proliferation reached the highest level and cellular density gradually increased until day 90. The relative magnitude of cellular changes was higher in the intima vs . the media layer (100 vs . 2 times respectively). Cyclin-dependent kinase inhibitors (CDKIs) p27^Kip1 and p16^INKA remained unchanged, whereas p21^Cip1 was gradually downregulated, reaching the lowest levels by day 7 until day 90. Taken together, these data indicate for the first time that p21^Cip1 is the main CDKI protein modulated during the arterialization process the rat model of vein arterialization that may be useful to identify and validate new targets and interventions to improve the long-term patency of vein grafts.     

Hypoxanthine-guanine phosphoribosyltransferase deficiency in a patient with a Madrid II mutation

The hypoxanthine-guanine phosphoribosyltransferase deficiency is an inborn error of purine metabolism, linked to the X chromosome. The clinical phenotypes associated with HPRT deficiency varied according to the level of enzyme deficiency, with a large spectrum of neurologic features like self-injurious behaviour in patients with complete deficiency. We report a 20-year-old man who had asymmetric polyarthritis, tophi, hyperuricemia, nephrolithiasis and mild neurologic symptoms with undetectable levels of HPRT activity in lysed erythrocytes. The genetic study identified the c.143G>A mutation in exon 3, GAA CGT (CTT > GAA CAT CTT (48arg > his). The presence of gouty arthropathy and chronic hyperuricemia in a young patient with neurological symptoms, suggests HPRT deficiency for which it is necessary its enzyme and molecular determination.     

Age-dependent changes of nuclear morphology are uncoupled from longevity in Caenorhabditis elegans IGF/insulin receptor daf-2 mutants

Nuclear envelope (NE) architecture and aging have been associated since the discovery that certain human progeria diseases are due to perturbations in processing of lamin A protein, generating alterations in NE morphology. However, whether changes in the NE are a causal effect of normal and premature aging is still controversial. Caenorhabditis elegans is a model organism where observations supporting both, dependent and independent roles of nuclear architecture in the aging process, have been reported. We found that the long-lived glp-1 mutant and dietary restriction delayed age-associated nuclear morphology changes. In addition, we observed that the long-lived mutant of the insulin/IGF receptor daf-2 delayed the age-dependent changes of nuclear architecture at 25 °C, as previously described. However, when daf-2 animals were incubated at 20 °C they remained long-lived, but nuclear appearance changed at similar rate as in the wild type. This supports the idea that both phenotypes, longevity and maintenance of nuclear architecture are tightly associated but can be separated and argues that nuclear morphology deterioration is not a cause of the natural aging process.