Intra-articular Contact Stress Distributions at the Ankle Throughout Stance Phase–patient-specific Finite Element Analysis as a Metric of Degeneration Propensity

A contact finite element (FE) formulation is introduced, amenable to patient-specific analysis of cumulative cartilage mechano-stimulus attributable to habitual functional activity. CT scans of individual human ankles are segmented to delineate bony margins. Each bone surface is projected outward to create a second surface, and the intervening volume is then meshed with continuum hexahedral elements. The tibia is positioned relative to the talus into a weight-bearing apposition. The articular members are first engaged under light preload, then plantar-/dorsi-flexion kinematics and resultant loadings are input for serial FE solutions at 13 instants of the stance phase of level walking gait. Cartilage stress histories are post-processed to recover distributions of cumulative stress-time mechano-stimulus, a metric of degeneration propensity. Consistency in computed contact stress exposures presented for seven intact ankles stood in contrast to the higher magnitude and more focal exposures in an incongruously reduced tibial plafond fracture. This analytical procedure provides patient-specific estimates of degeneration propensity due to various mechanical abnormalities, and it provides a platform from which the mechanical efficacy of alternative surgical interventions can be estimated.     

Nitric oxide produced in response to engagement of beta2 integrins on human neutrophils activates the monomeric GTPases Rap1 and Rap2 and promotes adhesion

We found that engagement of beta2 integrins on human neutrophils increased the levels of GTP-bound Rap1 and Rap2. Also, the activation of Rap1 was blocked by PP1, SU6656, LY294002, GF109203X, or BAPTA-AM, which indicates that the downstream signaling events in Rap1 activation involve Src tyrosine kinases, phosphoinositide 3-kinase, protein kinase C, and release of calcium. Surprisingly, the beta2 integrin-induced activation of Rap2 was not regulated by any of the signaling pathways mentioned above. However, we identified nitric oxide as the signaling molecule involved in beta2 integrin-induced activation of Rap1 and Rap2. This was illustrated by the fact that engagement of beta2 integrins increased the production of nitrite, a stable end-product of nitric oxide. Furthermore, pretreatment of neutrophils with Nomega-monomethyl-L-arginine, or 1400W, which are inhibitors of inducible nitric-oxide synthase, blocked beta2 integrin-induced activation of Rap1 and Rap2. Similarly, Rp-8pCPT-cGMPS, an inhibitor of cGMP-dependent serine/threonine kinases, also blunted the beta2 integrin-induced activation of Rap GTPases. Also nitric oxide production and its downstream activation of cGMP-dependent serine/threonine kinases were essential for proper neutrophil adhesion by beta2 integrins. Thus, we made the novel findings that beta2 integrin engagement on human neutrophils triggers production of nitric oxide and its downstream signaling is essential for activation of Rap GTPases and neutrophil adhesion.     

Influence of low phosphorus concentration on leaf photosynthetic characteristics and antioxidant response of rice genotypes

Influence of different phosphorus concentrations was studied in four rice varieties (Akhanphou, MTU1010, RP BIO 226, and Swarna) differing in their tolerance to low phosphorus. There was an increase in shoot and root dry mass with the increase in phosphorus concentration. At the low phosphorus concentration at both tillering and reproductive stages, Swarna, followed by Akhanphou, recorded maximum biomass for both roots and shoots, while the minimum was observed in RP BIO 226. Reduction in photosynthetic rate, stomatal conductance, transpiration rate, and internal CO₂ concentration at low phosphorus concentrations were observed at both tillering and reproductive stages in all the genotypes. In low phosphorus, maximum photosynthetic rate was found in Swarna followed by Akhanphou. Phosphorus deficiency did not alter the maximum efficiency of PSII photochemistry, however, there was a reduction in effective PSII quantum yield, electron transport rate, and coefficient of photochemical quenching, while the coefficient of nonphotochemical quenching was higher in the low phosphorus-treated plants. Prolonged exposure to excessive energy and failure to utilize the energy in carbon-reduction cycle induced the generation of reactive oxygen species, which affected PSII as indicated by the fluorescence traits. The reduction was less severe in case of Swarna and Akhanphou. The activities of superoxide dismutase, peroxidase, and catalase increased in roots under low phosphorus concentration indicating that photoprotective mechanisms have been initiated in rice plants in response to phosphorus deficiency. Comparatively, Swarna and Akhanphou exhibited a higher biomass, higher photosynthetic rate, and better reactive oxygen species-scavenging ability which conferred tolerance under low phosphorus conditions.     

Malaria prevalence in Mangaluru city area in the southwestern coastal region of India

Background

Malaria is highly prevalent in many parts of India and the Indian subcontinent. Mangaluru, a city in the southwest coastal region of Karnataka state in India, and surrounding areas are malaria endemic with 10–12 annual parasite index. Despite high endemicity, to-date, very little has been reported on the epidemiology and burden of malaria in this area.

Methods

A cross-sectional surveillance of malaria cases was performed among 900 febrile symptomatic native people (long-time residents) and immigrant labourers (temporary residents) living in Mangaluru city area. During each of dry, rainy, and end of rainy season, blood samples from a group of 300 randomly selected symptomatic people were screened for malaria infection. Data on socio-demographic, literacy, knowledge of malaria, and treatment-seeking behaviour were collected to understand the socio-demographic contributions to malaria menace in this region.

Results

Malaria is prevalent in Mangaluru region throughout the year and Plasmodium vivax is predominant species compared to Plasmodium falciparum. The infection frequency was found to be high during rainy season. Infections were markedly higher in males than females, and in adults aged 16–45 years than both younger and older age groups. Also, malaria incidence was high among immigrants compared to native population. In both groups, infection rate was directly correlated with their literacy level, knowledge on malaria, dwelling environment, and protective measures used. There was also a significant difference in treatment-seeking behaviour between these two groups.

Conclusions

Malaria incidences in Mangaluru region are predominantly localized to certain hotspot areas within the city, where socioeconomically underprivileged and immigrant labourers are densely populated. These areas have inadequate sanitation and constant water stagnation, harbouring high vector density and contributing to high infection incidences. Additionally, people in these areas seldom practice preventive measures such as using bed nets. The high incidences of malaria in adults are due to minimal cloth wearing, and long working hours stretching to late evenings in places with high vector density. Instituting heightened preventive public measures by governments and creating awareness on using preventive protective and environmental hygienic measures through educational programmes may substantially reduce the risk of contracting infections in these areas and spreading to other areas.

     

Photoluminescent properties of novel design heteroleptic Zn(II) complexes

Three novel heteroleptic Zn(II) complexes containing 8‐hydroxy quinoline and various pyrazolone‐based derivatives were synthesized and their structures confirmed by ¹H–nuclear magnetic resonance, mass spectrometry, Fourier transform infra‐red spectroscopy, UV–vis analysis and element analysis. All three complexes showed good photoluminescence properties in the solid state and in solution in the maximum emission range from 475 to 490 nm with a quantum yield of 0.45 to 0.51. Absorption spectra revealed that the complexes possessed a maximum absorption range of 272–281 nm with a band gap of 2.59–2.68 eV. The highest occupied molecular orbital and lowest unoccupied molecular orbital of all the complexes were determine by cyclic voltammetry. All complexes displayed high thermal stability. These characteristics were assessed to find suitability for an alternative cheap light emitter for organic light‐emitting diodes.     

Formulation and <Emphasis Type="Italic">In Vitro</Emphasis> Characterization of Thiolated Buccoadhesive Film of Fluconazole

The present work is focused on the development of thiolated film for fluconazole buccal delivery. To this end, unmodified polymers chitosan and sodium carboxymethylcellulose (NaCMC) backbone was covalently modified by thioglycolic acid (TGA) and cysteine, respectively. The thiolated buccoadhesive film was evaluated in terms of thickness, weight uniformity, water-uptake capacity, drug content, and release patterns. Moreover, mucoadhesion profile was investigated on buccal mucosa. The resulting chitosan–TGA and NaCMC–cysteine conjugates displayed 171?±?13 and 380?±?19 μmol thiol groups per gram of polymer (mean?±?SD; n?=?3), respectively. The water binding capacity of the thiolated film was significantly ～2-fold higher (p?<?0.05) as compared to unmodified film. The obtained thiolated film displayed 5.8-fold higher mucoadhesive properties compared with corresponding film. Controlled release of drugs from film was observed over 8 h. The transport of fluconazole across excised buccal mucosa was enhanced up to 17-fold in comparison with fluconazole applied in buffer. Based on these findings, thiolated film seems to be promising for fluconazole buccal delivery.     

Auxin biosynthetic intermediate genes and their role in developmental growth and plasticity in higher plants

Auxins are a group of phytohormones that regulate several aspects of plant growth and development. Indole-3-acetic acid (IAA) is the predominant form of auxin in plants and several IAA biosynthetic pathways have been previously proposed but remain genetically uncharacterized. One of the proposed pathways is the indole-3-pyruvic acid (IPyA) pathway, which is inferred to regulate key developmental processes such as apical hook formation and shade avoidance. Recent molecular evidence suggests the existence of the pathway in higher plants but remains unverified due to the elusive nature of IPyA in vitro. Extending on these recent advances, this research was aimed at investigating aspects of IPyA-dependent auxin biology in Pisum sativum (pea) using reverse genetics, expression profiling, and analytical techniques. As a result the genes PsTAR2, PsTAR 5g Mt 80, and PsTAR 5g Mt 90, which are inferred to encode key enzymes in the IPyA pathway, were cloned. On expression analysis PsTAR2 was found to be slightly heightened in response to IPyA-inducing conditions (shade) while IAA levels remained unaltered contrary to previous reports. Moreover, the inferred homologs PsTAR 5g Mt 80 and PsTAR 5g Mt 90 appeared down-regulated in the same conditions suggesting functional divergence in the gene family. Thus, PsTAR2 was thought to be solely responsible for regulating IPyA-dependent auxin synthesis. Consequently, using a reverse genetic approach, called TILLING, the PsTAR2 gene was mutated in order to study the down-stream effects of IPyA deficiency. The procedure is currently underway and in the process of isolating two novel pstar2 (IPyA) mutant lines consisting of a missense mutation (pstar2 4280) and a highly desired knockout mutation (pstar2 918). On completion the novel mutants are anticipated to be indispensable to future IPyA-auxin investigations in higher plants. In light of the unstable nature of IPyA, a protocol has been formulated using UPLC for fractioning followed by MS/MS analysis. This technique appears to be very promising as a robust IPyA detection protocol in plant extracts.     

In vivo evaluation of [18F]FECIMBI-36, an agonist 5-HT2A/2C receptor PET radioligand in nonhuman primate

We recently reported the radiosynthesis and in vitro evaluation of [¹⁸F]-2-(4-bromo-2,5-dimethoxyphenyl)-N-(2-(2-fluoroethoxy)benzyl)ethanamine, ([¹⁸F]FECIMBI-36) or ([¹⁸F]1), an agonist radioligand for 5HT_2A/2C receptors in postmortem samples of human brain. Herein we describe the in vivo evaluation of [¹⁸F]FECIMBI-36 in vervet/African green monkeys by PET imaging. PET images show that [¹⁸F]FECIMBI-36 penetrates the blood-brain barrier and a low retention of radioactivity is observed in monkey brain. Although the time activity curves indicate a somehow heterogeneous distribution of the radioligand in the brain, the low level of [¹⁸F]FECIMBI-36 in brain may limit the use of this tracer for quantification of 5-HT_2A/2C receptors by PET.     

Radiolabeling and initial biological evaluation of [18F]KBM-1 for imaging RAR-α receptors in neuroblastoma

Retinoic acid receptor alpha (RAR-α) plays a significant role in a number of diseases, including neuroblastoma. Children diagnosed with high-risk neuroblastoma are treated 13-cis-retinoic acid, which reduces risk of cancer recurrence. Neuroblastoma cell death is mediated via RAR-α, and expression of RAR-α is upregulated after treatment. A molecular imaging probe that binds RAR-α will help clinicians to diagnose and stratify risk for patients with neuroblastoma, who could benefit from retinoid-based therapy. In this study, we report the radiolabeling, and initial in vivo evaluation of [¹⁸F]KBM-1, a novel RAR-α agonist. The radiochemical synthesis of [¹⁸F]KBM-1 was carried out through KHF₂ assisted substitution of [¹⁸F]^? from aryl-substituted pinacolatoesters-based retinoid precursor. In vitro cell uptake assay in human neuroblastoma cell line showed that the uptake of [¹⁸F]KBM-1 was significantly inhibited by all three blocking agents (KBM-1, ATRA, BD4) at all the selected incubation times. Standard biodistribution in mice bearing neuroblastoma tumors demonstrated increased tumor uptake from 5 min to 60 min post radiotracer injection and the uptake ratios for target to non-target (tumor: muscle) increased 2.2-fold to 3.7-fold from 30 min to 60 min post injection. Tumor uptake in subset of 30 min blocking group was 1.7-fold lower than unblocked. These results demonstrate the potential utility of [¹⁸F]KBM-1 as a RAR-α imaging agent.