Experimental Study on Plasmodium knowlesi Normocyte Binding Protein Xa Region II (PkNBPXaII) for Erythrocyte Binding.

Normocyte binding protein Xa (NBPXa) has been implied to play a significant role in parasite invasion of human erythrocytes. Previous phylogenetic studies have reported the existence of three types of NBPXa for Plasmodium knowlesi (PkNBPXa). PkNBPXa region II (PkNBPXaII) of type 1, type 2 and type 3 were expressed on mammalian cell surface and interacted with human and macaque (Macaca fascicularis) erythrocytes. The binding activities of PkNBPXaII towards human and macaque erythrocytes were evaluated using erythrocyte-binding assay (EBA). Three parameters were evaluated to achieve the optimal protein expression of PkNBPXaII and erythrocyte binding activity in EBA: types of mammalian cells, post transfection time and erythrocyte incubation time. COS-7, HEK-293, and CHO-K1 cells showed successful expression of PkNBPXaII, despite the protein expression is weak compared to the positive control. COS-7 was used in EBA. All three types of PkNBPXaII showed rosette formation with macaque erythrocytes but not with human erythrocytes. Future studies to enhance the PkNBPXaII expression on surface of mammalian cells is indeed needed in order to elucidate the specific role of PkNBPXaII in erythrocytes invasion.

Complications of Sub-microscopic Plasmodium vivax Malaria among Orang Asli in Pos Lenjang, Kuala Lipis.

In recent years, increasing cases of Plasmodium vivax complications had been reported all over the world. This former benign Plasmodium species is now recognized to be one of the human malaria parasites that can produce severe disease. In this article, we report two cases of sub-microscopic P. vivax malaria confirmed by PCR. Both patients were asymptomatic before treatment. They showed unusual presentations few days after initiation of antimalarial treatment. Both patients had subsequently completed antimalarial treatment and recovered completely.

Predictive model of surgical remission in acromegaly: age, presurgical GH levels and Knosp grade as the best predictors of surgical remission.

PURPOSE: To identify presurgical clinical, hormonal and radiological variables associated with surgical remission in acromegaly and develop a predictive model for surgical remission. METHODS: Ambispective study of acromegaly surgical patients followed in two Spanish tertiary hospitals. Patients operated by the same neurosurgeon by endonasal endoscopic transsphenoidal approach (n = 49) were included to develop the predictive model, and patients operated by other neurosurgeons (n = 37) were used for external validation of the predictive model. The predictive model was developed with a multivariate logistic regression model based on the 2000 criteria. RESULTS: 86 acromegalic patients were included. 49 patients, 83.7% with macroadenomas and 32.7% with Knosp grade > 2, were included for the development of the predictive model. The overall rate of surgical remission with the 2000 criteria was 73.5% and 51.0% with the 2010 criteria. Using the 2000 criteria, variables associated with surgical remission were: older age (OR = 1.1, p = 0.001), lower basal presurgical GH levels (OR = 0.9, p = 0.003), Knosp 0-2 (OR = 34.1, p < 0.0001) and lower maximum pituitary adenoma diameter (OR = 0.9, p = 0.019). The model with the best diagnostic accuracy to predict surgical remission combined age, Knosp 0-2 and presurgical GH levels (AIC = 29.7, AUC = 0.95) with a sensitivity of 93.8% and a specificity of 75.0%. The estimated loss of prediction with the external validation (n = 37) was 4.2%. CONCLUSION: The predictive model with the best diagnosis accuracy for surgical remission combined age, Knosp 0-2 and presurgical GH levels, with a sensitivity of 93.8% and a specificity of 75.0%. This model could be very useful to select candidates to preoperative medical treatment and planning the follow-up.

Complications of Sub-microscopic Plasmodium vivax Malaria among Orang Asli in Pos Lenjang, Kuala Lipis

@#In recent years, increasing cases of Plasmodium vivax complications had been reported all over the world. This former benign Plasmodium species is now recognized to be one of the human malaria parasites that can produce severe disease. In this article, we report two cases of sub-microscopic P. vivax malaria confirmed by PCR. Both patients were asymptomatic before treatment. They showed unusual presentations few days after initiation of antimalarial treatment. Both patients had subsequently completed antimalarial treatment and recovered completely.

Experimental Study on Plasmodium knowlesi Normocyte Binding Protein Xa Region II (PkNBPXaII) for Erythrocyte Binding

@# Normocyte binding protein Xa (NBPXa) has been implied to play a significant role in parasite invasion of human erythrocytes. Previous phylogenetic studies have reported the existence of three types of NBPXa for Plasmodium knowlesi (PkNBPXa). PkNBPXa region II (PkNBPXaII) of type 1, type 2 and type 3 were expressed on mammalian cell surface and interacted with human and macaque (Macaca fascicularis) erythrocytes. The binding activities of PkNBPXaII towards human and macaque erythrocytes were evaluated using erythrocyte-binding assay (EBA). Three parameters were evaluated to achieve the optimal protein expression of PkNBPXaII and erythrocyte binding activity in EBA: types of mammalian cells, post transfection time and erythrocyte incubation time. COS-7, HEK-293, and CHO-K1 cells showed successful expression of PkNBPXaII, despite the protein expression is weak compared to the positive control. COS-7 was used in EBA. All three types of PkNBPXaII showed rosette formation with macaque erythrocytes but not with human erythrocytes. Future studies to enhance the PkNBPXaII expression on surface of mammalian cells is indeed needed in order to elucidate the specific role of PkNBPXaII in erythrocytes invasion.

Investigative study on the role of the Toxo 5699 gene in the Toxoplasma gondii lytic cycle using the CRISPR/Cas9 system.

The focus of the current study was to disrupt the Toxo 5699 gene via CRISPR/Cas9 to evaluate the effects of gene disruption on the parasite lytic cycle. In the present work, a single plasmid expressing both the guide RNA and Cas9 nuclease together with a selectable marker of human dihydrofolate reductase (DHFR) was introduced into Toxoplasma gondii. Targeted disruption of the Toxo 5699 gene was carried out via the CRISPR/Cas9 system and confirmed by PCR, sequencing, and immunofluorescence microscopy. Disrupted and nondisrupted control parasites were allowed to invade HS27 cell monolayers and plaques were counted. The average number of plaques from three replicates per group was obtained between the disrupted and non-disrupted T. gondii RH strain and was compared using a onetailed t-test. It was observed that there was a significant decrease in number and size of plaque formation in the Toxo 5699 gene disrupted parasite line. This is an indication that the Toxo 5699 gene may play a role in the lytic cycle of the parasite, particularly during the replication phase and thus would be a novel target for disruption or silencing. The Toxo 5699 gene presented in the current work is an important part of the T. gondii lytic cycle, therefore meriting further inquiry into its potential as a target for further genetic-silencing or disruption studies.

Investigative study on the role of the Toxo 5699 gene in the Toxoplasma gondii lytic cycle using the CRISPR/Cas9 system

@#The focus of the current study was to disrupt the Toxo 5699 gene via CRISPR/Cas9 to evaluate the effects of gene disruption on the parasite lytic cycle. In the present work, a single plasmid expressing both the guide RNA and Cas9 nuclease together with a selectable marker of human dihydrofolate reductase (DHFR) was introduced into Toxoplasma gondii. Targeted disruption of the Toxo 5699 gene was carried out via the CRISPR/Cas9 system and confirmed by PCR, sequencing, and immunofluorescence microscopy. Disrupted and nondisrupted control parasites were allowed to invade HS27 cell monolayers and plaques were counted. The average number of plaques from three replicates per group was obtained between the disrupted and non-disrupted T. gondii RH strain and was compared using a onetailed t-test. It was observed that there was a significant decrease in number and size of plaque formation in the Toxo 5699 gene disrupted parasite line. This is an indication that the Toxo 5699 gene may play a role in the lytic cycle of the parasite, particularly during the replication phase and thus would be a novel target for disruption or silencing. The Toxo 5699 gene presented in the current work is an important part of the T. gondii lytic cycle, therefore meriting further inquiry into its potential as a target for further genetic-silencing or disruption studies.

Barriers for Cataract Treatment among Elderly in Sri Lanka.

Cataract is still the leading cause of blindness. Many government institutes and voluntary organizations in Sri Lanka are providing free treatment services to patients with cataract. Still people are not patronizing the available free services; thus they have to live with impaired vision or blindness. This paper describes the barriers for cataract treatment among the population over 60 years of age. Out of 470 elders, 379 were found to have some kind of cataract. This study demonstrated lack of awareness and knowledge, socioeconomic factors, and misconceptions as the main barriers for cataract treatment which has led to a lower cataract surgery rate irrespective of the high cataract prevalence reported. Findings of this study highlight the importance of cataract as a common health problem in elderly and need for removal of the barriers for its treatment which should be given due prominence in the formulation of public health policy in Sri Lanka at the earliest.

Symmetric and asymmetric instability of buried polymer interfaces.

We demonstrate using neutron reflectometry that the internal interfaces in a trilayer system of two identical thick polystyrene layers sandwiching a much thinner (deuterated) poly(methyl methacrylate) layer 15 nm thick (viscosity matched with the polystyrene layers) increase in roughness at the same rate. When the lower polystyrene layer is replaced with a layer of the same polymer of much greater molecular mass, two different growths of the interfaces are observed. From the growth of the interface for this asymmetric case in the solid regime using the theoretical prediction of the spinodal instability including slippage at the interface, a value of the Hamaker constant of the system has been extracted in agreement with the calculated value. For the symmetric case the rise time of the instability is much faster.

Rheo-SAXS investigation of shear-thinning behaviour of very anisometric repulsive disc-like clay suspensions.

Aqueous suspensions of swelling clay minerals exhibit a rich and complex rheological behaviour. In particular, these repulsive systems display strong shear-thinning at very low volume fractions in both the isotropic and gel states. In this paper, we investigate the evolution with shear of the orientational distribution of aqueous clay suspensions by synchrotron-based rheo-SAXS experiments using a Couette device. Measurements in radial and tangential configurations were carried out for two swelling clay minerals of similar morphology and size, Wyoming montmorillonite and Idaho beidellite. The shear evolution of the small angle x-ray scattering (SAXS) patterns displays significantly different features for these two minerals. The detailed analysis of the angular dependence of the SAXS patterns in both directions provides the average Euler angles of the statistical effective particle in the shear plane. We show that for both samples, the average orientation is fully controlled by the local shear stress around the particle. We then apply an effective approach to take into account multiple hydrodynamic interactions in the system. Using such an approach, it is possible to calculate the evolution of viscosity as a function of shear rate from the knowledge of the average orientation of the particles. The viscosity thus recalculated almost perfectly matches the measured values as long as collective effects are not too important in the system.

Rheological behaviour of polyoxometalate-doped lyotropic lamellar phases.

We study the influence of nanoparticle doping on the lyotropic liquid crystalline phase of the industrial surfactant Brij®30 (C12E4) and water, doped with spherical polyoxometalate nanoparticles smaller than the characteristic dimensions of the host lamellar phase. We present viscometry and in situ rheology coupled with small-angle X-ray scattering data that show that, with increasing doping concentration, the nanoparticles act to decrease the shear viscosity of the lamellar phase, and that a shear-induced transition to a multilamellar vesicle "onion" phase is pushed to higher shear rates, and in some cases completely suppressed. X-ray data reveal that the nanoparticles remain encapsulated within the membranes of the vesicles, thus indicating a viable method for the fabrication of nanoparticle incorporating organic vesicles.

Clozapine-associated weight loss.

Clozapine is associated with weight gain. We report three patients with substantial weight loss following treatment with clozapine. The weight loss observed in the three patients was 33, 18 and 14.4 kg with percentage loss of body weight of 49, 18 and 21 respectively. Two patients had diabetes mellitus. History, physical examination and extensive investigations in the three patients did not reveal any cause that could account for the weight loss.

Switching layer stability in a polymer bilayer by thickness variation.

We use optical and scanning force microscopy to explore the possibility of switching the stability of a bilayer of poly(methyl methacrylate) (PMMA) on polystyrene by simply changing the film thickness. We show that for thin PMMA layers on thicker polystyrene films the PMMA layer is unstable to thickness fluctuations. However, polystyrene layers are unstable when they are substantially thinner than the now stable PMMA film. Dewetting morphologies are cataloged as a function of the thickness of individual polymer layers by identifying which layer is unstable by which mechanism, be it spinodal dewetting or heterogeneous thermal nucleation. Our results are in good agreement with a linear stability analysis of the influence of long-range dispersion forces, but also indicate the influence of film preparation and small variations of material properties.

Idiopathic purpura fulminans in dengue hemorrhagic fever.

Purpura fulminans is a rapidly progressive thrombotic disease that has been described during both severe bacterial and viral infections. Disseminated intravascular coagulation (DIC), antiphospholipid antibodies and acquired or congenital C and S protein deficiency are thought to play a role in its pathogenesis. Here we report the case of a 4-year-old girl who developed gangrene of all her fingers and toes following dengue shock syndrome complicated by DIC and also discuss its management.

Normal blood pressure and renal function in mice lacking the bradykinin B(2) receptor.

Telemetric blood pressure determinations, heart rate measurements, and pressure-natriuresis-diuresis experiments were used to characterize cardiovascular and renal function in bradykinin B(2) receptor knockout mice fed mouse chow containing 0.25% NaCl or mouse chow containing 4% NaCl. In B(2) receptor knockout mice fed usual mouse chow, the mean arterial blood pressure leveled between 108+/-1 and 110+/-3 mm Hg, and the heart rate leveled between 520+/-26 and 525+/-29 bpm, values that were not different from those measured in B(1) receptor knockout mice or 129Sv/J control mice. Increasing dietary salt intake did not affect mean arterial blood pressure and heart rate. Accordingly, pressure-natriuresis curves, pressure-diuresis curves, renal blood flow, and glomerular filtration rate were not different between B(2) receptor knockout and 129Sv/J mice. Increasing dietary salt intake to 4% increased renal blood flow to levels between 8.41 and 9.50 mL/min per gram kidney wet weight in 129Sv/J mice, whereas in B(2) receptor-deficient mice, renal blood flow was not affected and ranged between 6.85 and 7.88 mL/min per gram kidney wet weight. Other renal function parameters were not affected. Absence of B(2) receptor function was verified in B(2) receptor knockout mice with bradykinin infusion. These data suggest that the absence of B(2) receptor function does not necessarily make B(2) receptor knockout mice hypertensive or induce salt sensitivity. Presumably, differences in the genetic background or an adaptation to the loss of B(2) receptor function may account for these results, in contrast with earlier reports involving B(2) receptor knockout mice. We hold the latter possibility to be more likely and to be a fruitful possibility for future research.

In-continuity fundic bypass for palliation in unresectable carcinoma of the oesophagus: a previously unreported procedure.

Surgical bypass for the palliation of dysphagia in patients with unresectable oesophageal carcinoma continues to be an option in developing countries, as the cost of a good quality endo-prosthesis is well beyond the means of most patients. One such case is presented in which an in-continuity fundic bypass (without resection of the lesser curvature and cardia, thereby not disconnecting the oesophago-gastric junction) was made with gratifying results with regard to quality of life. Awareness of this previously unreported procedure is important because it adds to the armamentarium of surgeons wanting to provide palliation for dysphagia and aspiration in patients with unresectable carcinoma of the oesophagus.

Characterisation of two tomato fruit-expressed cDNAs encoding xyloglucan endo-transglycosylase.

Xyloglucan endo-transglycosylase (XET) catalyses the cleavage and concomitant transfer of one xyloglucan molecule to another. It is thought to be an important component of cell wall metabolism, particularly in expanding tissue and ripening fruits. The recently reported cloning of a cDNA encoding a seed-expressed XET from nasturtium [9] has enabled two XET-encoding cDNAs to be isolated from a tomato fruit (breaker stage) cDNA library. Their deduced amino acid sequences exhibit ca. 40% identity to nasturtium XET. One of the tomato cDNA clones (tXET-B2) was over-expressed in Escherichia coli; following purification and refolding, the recombinant protein was shown to have XET activity, with no detectable hydrolytic activity. Southern hybridisation analysis suggests that these clones are members of a small multi-gene family encoding tomato XET. Ribonuclease protection assays show that transcripts protected by one of the clones (tXET-B1) are most abundant in pink fruit pericarp and were also detected in stems.

Regulated expression of the rat medium chain hydrolase gene in transgenic rape seed.

Medium chain hydrolase (MCH) is an enzyme which regulates the chain length of fatty acid synthesis specifically in the mammary gland of the rat. During lactation, MCH interacts with fatty acid synthase (FAS) to cause premature release of acyl chains, thus providing medium chain fatty acids for synthesis of milk fat. In this study we have investigated the ability of rat MCH to interact with the phylogenetically more distant FAS structure present in plant systems and to cause a perturbation of fatty acid synthesis. In in vitro experiments, addition of purified MCH to rapeseed homogenates was found to cause a significant perturbation of fatty acid synthesis towards medium chain length products. The rat MCH gene was expressed in transgenic oilseed rape using a seed specific rape acyl carrier protein (ACP) promoter and a rape ACP plastid targeting sequence. Western analysis showed MCH protein to be present in transgenic seed and for its expression to be developmentally regulated in concert with storage lipid synthesis. The chimaeric preprotein was correctly processed and immunogold labelling studies confirmed MCH to be localized within plastid organelles. However, fatty acid analysis of oil from MCH-expressing rape seed showed no significant differences to that from control seed.