Hypophosphatasia is an inborn error of metabolism characterized by deficient activity of the tissue‐nonspecific isoenzyme of alkaline phosphatase (TNSALP) and skeletal disease due to impaired ...mineralization of cartilage and bone matrix. We investigated two independently generated TNSALP gene knock‐out mouse strains as potential models for hypophosphatasia. Homozygous mice (–/–) had < 1% of wild‐type plasma TNSALP activity; heterozygotes had the predicted mean of ∼50%. Phosphoethanolamine, inorganic pyrophosphate, and pyridoxal 5′‐phosphate are putative natural substrates for TNSALP and all were increased endogenously in the knock‐out mice. Skeletal disease first appeared radiographically at ∼10 days of age and featured worsening rachitic changes, osteopenia, and fracture. Histologic studies revealed developmental arrest of chondrocyte differentiation in epiphyses and in growth plates with diminished or absent hypertrophic zones. Progressive osteoidosis from defective skeletal matrix mineralization was noted but not associated with features of secondary hyperparathyroidism. Plasma and urine calcium and phosphate levels were unremarkable. Our findings demonstrate that TNSALP knock‐out mice are a good model for the infantile form of hypophosphatasia and provide compelling evidence for an important role for TNSALP in postnatal development and mineralization of the murine skeleton.
Summary
The widespread use of chloroquine to treat Plasmodium falciparum infections has resulted in the selection and dissemination of variant haplotypes of the primary resistance determinant PfCRT. ...These haplotypes have encountered drug pressure and within‐host competition with wild‐type drug‐sensitive parasites. To examine these selective forces in vitro, we genetically engineered P. falciparum to express geographically diverse PfCRT haplotypes. Variant alleles from the Philippines (PH1 and PH2, which differ solely by the C72S mutation) both conferred a moderate gain of chloroquine resistance and a reduction in growth rates in vitro. Of the two, PH2 showed higher IC50 values, contrasting with reduced growth. Furthermore, a highly mutated pfcrt allele from Cambodia (Cam734) conferred moderate chloroquine resistance and enhanced growth rates, when tested against wild‐type pfcrt in co‐culture competition assays. These three alleles mediated cross‐resistance to amodiaquine, an antimalarial drug widely used in Africa. Each allele, along with the globally prevalent Dd2 and 7G8 alleles, rendered parasites more susceptible to lumefantrine, the partner drug used in the leading first‐line artemisinin‐based combination therapy. These data reveal ongoing region‐specific evolution of PfCRT that impacts drug susceptibility and relative fitness in settings of mixed infections, and raise important considerations about optimal agents to treat chloroquine‐resistant malaria.
Chloroquine resistance in Plasmodium falciparum is mediated by mutant isoforms of the digestive vacuole transporter PfCRT that generally impart a fitness cost. We report that a highly mutated allele from Cambodia has evolved to mediate low‐level resistance with no evident reduction in relative growth rate in vitro. Our data suggest an ongoing evolution of pfcrt alleles in Cambodia and the Philippines that impact parasite fitness as well as susceptibility to multiple antimalarials in clinical use.
Development of academic-practice partnerships (APPs) provides the foundation to build a sustainable partnership between academia and practice settings. APPs provide academic, practice, and mutual ...benefits to advance ambulatory care nursing. Those who engage in partnerships can achieve mutual respect and understanding, a shared vision with mutual goals and outcomes, and agreed-upon evaluation strategies. Part 1 of a 3-part series.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
IL-33, a member of the IL-1 cytokine family that signals through ST2, is upregulated in ulcerative colitis (UC); however, the role of IL-33 in colitis remains unclear. IL-33 augments type 2 immune ...responses, which have been implicated in UC pathogenesis. We sought to determine the role of IL-33 signaling in oxazolone (OXA) colitis, a type 2 cytokine-mediated murine model of UC.
Colon mucosal IL-33 expression was compared between pediatric and adult UC and non-IBD patients using immunohistochemistry and real-time PCR. OXA colitis was induced in WT, IL-33, and ST2 mice, and histopathology, cytokine levels, and goblet cells were assessed. Transepithelial resistance was measured across IL-33-treated T84 cell monolayers.
Colon mucosal IL-33 was increased in pediatric patients with active UC and in OXA colitis. IL-33 and ST2 OXA mice exhibited increased disease severity compared with WT OXA mice. OXA induced a mixed mucosal cytokine response, but few differences were observed between OXA WT and IL-33 or ST2 mice. Goblet cells were significantly decreased in IL-33 and ST2 OXA compared with WT OXA mice. IL-33 augmented transepithelial resistance in T84 cells, and this effect was blocked by the ERK1/2 inhibitor PD98,059.
OXA colitis is exacerbated in IL-33 and ST2 mice. Increased mucosal IL-33 in human UC and murine colitis may be a homeostatic response to limit inflammation, potentially through effects on epithelial barrier function. Further investigation of IL-33 protective mechanisms would inform the development of novel therapeutic approaches.
Background: The effect of initial antiretroviral therapy (ART) class on cancer risk in people with HIV (PWH) remains unclear. Setting: A cohort study of 36,322 PWH enrolled (1996–2014) in the North ...American AIDS Cohort Collaboration on Research and Design. Methods: We followed individuals from ART initiation (protease inhibitor PI-based, nonnucleoside reverse transcriptase inhibitor NNRTI-based, or integrase strand transfer inhibitor INSTI-based) until incident cancer, death, loss-to-follow-up, December 31, 2014, 85 months (intention-to-treat analyses ITT), or 30 months (per-protocol PP analyses). Cancers were grouped (nonmutually exclusive) as follows: any cancer, AIDS-defining cancers (ADC), non-AIDS-defining cancers (NADC), any infection-related cancer, and common individual cancer types. We estimated adjusted hazard ratios (aHR) comparing cancer risk by ART class using marginal structural models emulating ITT and PP trials. Results: We observed 17,004 PWH (954 cancers) with PI-based (median 6 years follow-up), 17,536 (770 cancers) with NNRTI-based (median 5 years follow-up), and 1782 (29 cancers) with INSTI-based ART (median 2 years follow-up). Analyses with 85-month follow-up indicated no cancer risk differences. In truncated analyses, the risk of ADCs (aHR 1.33; 95% CI: 1.00, 1.77 PP analysis) and NADCs (aHR 1.23; 95% CI: 1.00 to 1.51 ITT analysis) was higher comparing PIs vs. NNRTIs. Conclusions: Results with longer-term follow-up suggest being on a PI-based versus NNRTI-based ART regimen does not affect cancer risk. We observed shorter-term associations that should be interpreted cautiously and warrant further study. Further research with a longer duration of follow-up that can evaluate INSTIs, the current first-line recommended therapy, is needed to comprehensively characterize the association between ART class and cancer risk.
Schematic diagram of spherical coordinate system for 3D printing cartridge on the stage of texture analyzer; and B) extrudability profile a sample 3D printing paste (Formulation F1) using texture ...analyzer.
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The rheological characteristics of pastes for 3D printing of tablets may not be described fully by the traditional rheological tests generally used for other pastes. In the present study, extrudability testing of carbopol based 3D printing pastes was performed to establish a constitutive rheological model for micro-extrusion. This model was developed for pastes that exhibit a non-linear plasto-viscoelastic behavior and follow the generalized Herschel–Bulkley flow rule. An analytical model was applied to extrudability data obtained by micro-extrusion through nozzles of 0.4 and 0.6 mm diameters. For this purpose, nineteen pastes were prepared per a fractional factorial design using various concentrations of the active ingredient and soluble and insoluble excipients. Critical material parameters (σ0, k and n) of the pastes were then calculated by analyzing extrudability data using a constitutive equation relating flow rate, nozzle and cartridge diameters, printing pressure and slip-flow angle. The accuracy of the constitutive model to predict paste yield stress, consistency and flow indices was evident by low RMSE values of 0.0691 bar, 0.034 and 6.3 bar/sn, respectively. Yield stress, flow and consistency parameters of the pastes were significantly affected by percentages of soluble and swellable excipients. The nozzle diameter had significant effect on flow index (n) but not on the consistency index (k). Hence, this study provides a mechanistic model to characterize the complex rheological behavior of pastes for 3D printing of tablets by a micro-extrusion process.
Breast cancer resistance protein (BCRP) is a newly identified ABC transporter, which plays an important role in drug disposition and represents an additional mechanism for the development of MDR. ...Flavonoids, a major class of natural compounds widely present in foods and herbal products, have been shown to be BCRP inhibitors. The objective of the present study was to elucidate the SAR and derive a QSAR model for flavonoid–BCRP interaction. The EC
50 values for increasing mitoxantrone accumulation in MCF-7 MX100 cells for 25 flavonoids, from five flavonoid subclasses, were determined in this study or obtained from our previous publication Zhang S, Yang X, Morris ME. Combined effects of multiple flavonoids on breast cancer resistance protein (ABCG2)-mediated transport. Pharm Res 2004;21(7):1263–73, and ranged from 0.07
±
0.02
μM to 183
±
21.7
μM. We found that the presence of a 2,3-double bond in ring C, ring B attached at position 2, hydroxylation at position 5, lack of hydroxylation at position 3 and hydrophobic substitution at positions 6, 7, 8 or 4′, are important structural properties important for potent flavonoid–BCRP interaction. These structural requirements are similar but not identical to those for potent flavonoid–NBD2 (P-glycoprotein) interaction, indicating that inhibition of BCRP by flavonoids may involve, in part, the binding of flavonoids with the NBD of BCRP. In addition, a QSAR model consisting three structural descriptors was constructed, and both internally and externally validated, suggesting the model could be used to quantitatively predict BCRP inhibition activity of flavonoids. These findings should be useful for predicting BCRP inhibition activity of other untested flavonoids and for guiding the synthesis of potent BCRP inhibitors for potential clinical application.
► An update on an ongoing consortium effort with an aim to develop a harmonized zebrafish developmental toxicity assay is given. ► 10 teratogens and 10 non teratogens were evaluated blinded in 4 ...laboratories. ► Laboratories achieved similar overall concordance (60–70% to animal data) despite the use of different zebrafish strains. ► Following integration of optimized procedures into the protocol, retesting of compounds in one lab achieved 85% concordance. ► To further assess performance, 40 proprietary compounds are in evaluation at 2 laboratories.
This report provides a progress update of a consortium effort to develop a harmonized zebrafish developmental toxicity assay. Twenty non-proprietary compounds (10 animal teratogens and 10 animal non-teratogens) were evaluated blinded in 4 laboratories. Zebrafish embryos from pond-derived and cultivated strain wild types were exposed to the test compounds for 5 days and subsequently evaluated for lethality and morphological changes. Each of the testing laboratories achieved similar overall concordance to the animal data (60–70%). Subsequent optimization procedures to improve the overall concordance focused on compound formulation and test concentration adjustments, chorion permeation and number of replicates. These optimized procedures were integrated into a revised protocol and all compounds were retested in one lab using embryos from pond-derived zebrafish and achieved 85% total concordance. To further assess assay performance, a study of additional compounds is currently in progress at two laboratories using embryos from pond-derived and cultivated-strain wild type zebrafish.
Management of secondary hyperparathyroidism is challenging with traditional therapy. The calcimimetic cinacalcet HCl acts on the calcium-sensing receptor to increase its sensitivity to calcium, ...thereby reducing parathyroid hormone (PTH) secretion. This phase 3, multicenter, randomized, placebo-controlled, double-blind study evaluated the efficacy and safety of cinacalcet in hemodialysis (HD) and peritoneal dialysis (PD) patients with PTH > or =300 pg/ml despite traditional therapy. A total of 395 patients received once-daily oral cinacalcet (260 HD, 34 PD) or placebo (89 HD, 12 PD) titrated from 30 to 180 mg to achieve a target intact PTH (iPTH) level of < or =250 pg/ml. During a 10-wk efficacy assessment phase, cinacalcet was more effective than control for PTH reduction outcomes, including proportion of patients with mean iPTH levels < or =300 pg/ml (46 versus 9%), proportion of patients with > or =30% reduction in iPTH from baseline (65 versus 13%), and proportion of patients with > or =20, > or =40, or > or =50% reduction from baseline. Cinacalcet had comparable efficacy in HD and PD patients; 50% of PD patients achieved a mean iPTH < or =300 pg/ml. Cinacalcet also significantly reduced serum calcium, phosphorus, and Ca x P levels compared with control treatment. The most common side effects, nausea and vomiting, were usually mild to moderate in severity and transient. Once-daily oral cinacalcet was effective in rapidly and safely reducing PTH, Ca x P, calcium, and phosphorus levels in patients who received HD or PD. Cinacalcet offers a new therapeutic option for controlling secondary hyperparathyroidism in patients with chronic kidney disease on dialysis.
Gastrectomy with negative resection margins and adequate lymph node dissection is the cornerstone of curative treatment for gastric cancer (gc). However, gastrectomy is a complex and invasive ...operation with significant morbidity and mortality. Little is known about surgical practice patterns or short- and long-term outcomes in early-stage gc in Canada.
We undertook a population-based retrospective cohort study of patients with gc diagnosed between 1 April 2005 and 31 March 2008. Chart review provided clinical and operative details such as disease stage, primary tumour location, surgical approach, operation, lymph nodes, and resection margins. Administrative data provided patient demographics, geography, and vital status. Variations in treatment and outcomes were compared for 14 local health integration networks. Descriptive statistics and log-rank tests were used to examine geographic variation.
We identified 722 patients with nonmetastatic resected gc. We documented significant provincial variation in case mix, including primary tumour location, stage at diagnosis, and tumour grade. Short-term surgical outcomes varied across the province. The percentage of patients with 15 or fewer lymph nodes removed and examined varied from 41.8% to 73.8% (
= 0.02), and the rate of positive surgical margins ranged from 15.2% to 50.0% (
= 0.002). The 30-day surgical mortality rates did not vary statistically significantly across the province (
= 0.13); however, rates ranged from 0% to 16.7%. Overall 5-year survival was 44% and ranged from 31% to 55% across the province.
This cohort of patients with resected stages i-iii gc is the largest analyzed in Canada, providing important historical information about treatment outcomes. Understanding the causes of regional variation will support interventions aiming to improve gc operative outcomes in the cancer system.
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