NFIC regulates ribosomal biology and ER stress in pancreatic acinar cells and restrains PDAC initiation

Pancreatic acinar cells rely on PTF1 and other transcription factors to deploy their transcriptional program. We identify NFIC as a NR5A2 interactor and regulator of acinar differentiation. NFIC binding sites are enriched in NR5A2 ChIP-Sequencing peaks. Nfic knockout mice have a smaller, histologically normal, pancreas with reduced acinar gene expression. NFIC binds and regulates the promoters of acinar genes and those involved in RNA/protein metabolism, and Nfic knockout pancreata show defective ribosomal RNA maturation. NFIC dampens the endoplasmic reticulum stress program through binding to gene promoters and is required for resolution of Tunicamycin-mediated stress. NFIC is down-regulated during caerulein pancreatitis and is required for recovery after damage. Normal human pancreata with low levels of NFIC transcripts display reduced expression of genes down-regulated in Nfic knockout mice. NFIC expression is down-regulated in mouse and human pancreatic ductal adenocarcinoma. Consistently, Nfic knockout mice develop a higher number of mutant Kras-driven pre-neoplastic lesions.

The PRSS3P2 and TRY7 deletion copy number variant modifies risk for chronic pancreatitis

BACKGROUND

PRSS1 and PRSS2 constitute the only functional copies of a tandemly-arranged five-trypsinogen-gene cluster (i.e., PRSS1, PRSS3P1, PRSS3P2, TRY7 and PRSS2) on chromosome 7q35. Variants in PRSS1 and PRSS2, including missense and copy number variants (CNVs), have been reported to predispose to or protect against chronic pancreatitis (CP). We wondered whether a common trypsinogen pseudogene deletion CNV (that removes two of the three trypsinogen pseudogenes, PRSS3P2 and TRY7) might be associated with CP causation/predisposition.

METHODS

We analyzed the common PRSS3P2 and TRY7 deletion CNV in a total of 1536 CP patients and 3506 controls from France, Germany, India and Japan by means of quantitative fluorescent multiplex polymerase chain reaction.

RESULTS

We demonstrated that the deletion CNV variant was associated with a protective effect against CP in the French, German and Japanese cohorts whilst a trend toward the same association was noted in the Indian cohort. Meta-analysis under a dominant model yielded a pooled odds ratio (OR) of 0.68 (95% confidence interval (CI) 0.52-0.89; p = 0.005) whereas an allele-based meta-analysis yielded a pooled OR of 0.84 (95% CI 0.77-0.92; p = 0.0001). This protective effect is explicable by reference to the recent finding that the still functional PRSS3P2/TRY7 pseudogene enhancers upregulate pancreatic PRSS2 expression.

CONCLUSIONS

The common PRSS3P2 and TRY7 deletion CNV was associated with a reduced risk for CP. This finding provides additional support for the emerging view that dysregulated PRSS2 expression represents a discrete mechanism underlying CP predisposition or protection.

A GATA6-centred gene regulatory network involving HNFs and ΔNp63 controls plasticity and immune escape in pancreatic cancer

OBJECTIVE

Molecular taxonomy of tumours is the foundation of personalised medicine and is becoming of paramount importance for therapeutic purposes. Four transcriptomics-based classification systems of pancreatic ductal adenocarcinoma (PDAC) exist, which consistently identified a subtype of highly aggressive PDACs with basal-like features, including ΔNp63 expression and loss of the epithelial master regulator GATA6. We investigated the precise molecular events driving PDAC progression and the emergence of the basal programme.

DESIGN

We combined the analysis of patient-derived transcriptomics datasets and tissue samples with mechanistic experiments using a novel dual-recombinase mouse model for Gata6 deletion at late stages of KRasG12D-driven pancreatic tumorigenesis (Gata6LateKO).

RESULTS

This comprehensive human-to-mouse approach showed that GATA6 loss is necessary, but not sufficient, for the expression of ΔNp63 and the basal programme in patients and in mice. The concomitant loss of HNF1A and HNF4A, likely through epigenetic silencing, is required for the full phenotype switch. Moreover, Gata6 deletion in mice dramatically increased the metastatic rate, with a propensity for lung metastases. Through RNA-Seq analysis of primary cells isolated from mouse tumours, we show that Gata6 inhibits tumour cell plasticity and immune evasion, consistent with patient-derived data, suggesting that GATA6 works as a barrier for acquiring the fully developed basal and metastatic phenotype.

CONCLUSIONS

Our work provides both a mechanistic molecular link between the basal phenotype and metastasis and a valuable preclinical tool to investigate the most aggressive subtype of PDAC. These data, therefore, are important for understanding the pathobiological features underlying the heterogeneity of pancreatic cancer in both mice and human.

Comparative evaluation of corneal incision enlargement after intraocular lens delivery of new preloaded and manual implantation systems

PURPOSE

To determine whether total corneal incision enlargement after implantation of an intraocular lens with a new preloaded delivery system is comparable to a standard-of-care manual delivery system using an in vitro human cadaver eye model, despite having a smaller initial incision size.

METHODS

Human cadaver phakic whole eye globes were used for these studies (n = 16 per group). Each pair of eyes was randomly assigned to a new preloaded delivery system (UltraSert^TM) or a manual delivery system (MONARCH^® III D). The surgical procedure included creating a 2.2- and 2.4-mm corneal incision for the preloaded and manual delivery systems, respectively, measuring intraocular pressure and pre-implantation corneal incision size, delivering the intraocular lens into the anterior chamber, and measuring the post-implantation incision size.

RESULTS

The final corneal incision enlargement after intraocular lens delivery using the preloaded delivery system was 2.33 ± 0.04 mm, compared to 2.54 ± 0.05 mm after intraocular lens delivery with the manual delivery system. The mean corneal incision enlargement was comparable between the two systems, being 0.13 ± 0.04 mm using the preloaded delivery system and 0.14 ± 0.05 mm using the manual delivery system (p = 0.432).

CONCLUSION

In a human cadaver eye model, the preloaded delivery system demonstrated an intraocular lens delivery performance on cornea incision enlargement was noninferior to the manual, standard-of-care intraocular lens delivery system despite a smaller initial incision size.

TRANSLATIONAL RELEVANCE

Smaller incision sizes for cataract surgery improve patient outcomes via faster visual and wound recovery and decreased risk of complications such as postoperative inflammation and surgically induced astigmatism.

Pharmacognostic, Phytochemical and Pharmacological Review of “Phog”- Calligonum polygonoides L

Calligonum polygonoides (Phog) belongs to family Polygonaceae. It is a geographically widely distributed shrub seen from the arctic to the tropics. This endangered plant (included in Red data book of IUCN) is morphologically having stem with nodes and internodes, white flowers in spike inflorescence and needle like leaves. It is traditionally used to stabilize sand dunes, as fuel, and in treatment of heat-stroke by mixing with curd or “Rayata”. It is also reported as antidote for opium poisoning. Various phyto-chemicals present include butanolides- calligonolides A and B, various flavanoids like kaempferol, quercetin and their derivatives. Various steroidal compounds are reported in roots. Pharmacologicallly, its cytotoxic, anti-inflammatory, antioxidant, antifungal and biosorbent potentials are reported by various researchers. Therefore, an attempt has been made to accumulate properties of this potential herb. Keywords: Calligonum, Phog, biosorbent, heat-stroke, calligonolides, kaempferol

Identification of a functional enhancer variant within the chronic pancreatitis-associated SPINK1 c.101A>G (p.Asn34Ser)-containing haplotype

The haplotype harboring the SPINK1 c.101A>G (p.Asn34Ser) variant (also known as rs17107315:T>C) represents the most important heritable risk factor for idiopathic chronic pancreatitis identified to date. The causal variant contained within this risk haplotype has however remained stubbornly elusive. Herein, we set out to resolve this enigma by employing a hypothesis-driven approach. First, we searched for variants in strong linkage disequilibrium (LD) with rs17107315:T>C using HaploReg v4.1. Second, we identified two candidate SNPs by visual inspection of sequences spanning all 25 SNPs found to be in LD with rs17107315:T>C, guided by prior knowledge of pancreas-specific transcription factors and their cognate binding sites. Third, employing a novel cis-regulatory module (CRM)-guided approach to further filter the two candidate SNPs yielded a solitary candidate causal variant. Finally, combining data from phylogenetic conservation and chromatin accessibility, cotransfection transactivation experiments, and population genetic studies, we suggest that rs142703147:C>A, which disrupts a PTF1L-binding site within an evolutionarily conserved HNF1A-PTF1L CRM located ∼4 kb upstream of the SPINK1 promoter, contributes to the aforementioned chronic pancreatitis risk haplotype. Further studies are required not only to improve the characterization of this functional SNP but also to identify other functional components that might contribute to this high-risk haplotype.

No Association Between CEL-HYB Hybrid Allele and Chronic Pancreatitis in Asian Populations

A hybrid allele between the carboxyl ester lipase gene (CEL) and its pseudogene, CELP (called CEL-HYB), generated by nonallelic homologous recombination between CEL intron 10 and CELP intron 10', was found to increase susceptibility to chronic pancreatitis in a case-control study of patients of European ancestry. We attempted to replicate this finding in 3 independent cohorts from China, Japan, and India, but failed to detect the CEL-HYB allele in any of these populations. The CEL-HYB allele might therefore be an ethnic-specific risk factor for chronic pancreatitis. An alternative hybrid allele (CEL-HYB2) was identified in all 3 Asian populations (1.7% combined carrier frequency), but was not associated with chronic pancreatitis.

Genetic and phenotypic heterogeneity in tropical calcific pancreatitis

Tropical calcific pancreatitis (TCP) is a form of chronic non-alcoholic pancreatitis initially reported in the developing parts of the tropical world. The clinical phenotype of TCP has undergone marked changes since its first description in 1968. The disease is now seen in relatively older people with less severe symptoms. In addition, there are varying reports on the proportion of cases presenting with imaging abnormalities like calcification, ductal dilation, and glandular atrophy. Significant progress has also been made in understanding the etiopathology of TCP. The role of malnutrition and cassava toxicity in its pathogenesis is disproven and few studies have focused on the role of micronutrient deficiency and oxidative stress in the etiopathogenesis of TCP. Emerging evidence support an important role for genetic risk factors in TCP. Several studies have shown that, rather than mutations in trypsinogens, variants in serine protease inhibitor kazal type 1, cathepsin B, chymotrypsin C, cystic fibrosis transmembrane regulator, and carboxypeptidase A1, predict risk of TCP. These studies also provided evidence of mutational heterogeneity between TCP and chronic pancreatitis in Western populations. The current review summarizes recent advances that have implications in the understanding of the pathophysiology and thus, heterogeneity in genotype-phenotype correlations in TCP.

A review of the metabolism of 1,4-butanediol diglycidyl ether-crosslinked hyaluronic acid dermal fillers

BACKGROUND

Cosmetic procedures are growing ever more common, and the use of soft tissue fillers is increasing. Practicing physicians need to be aware of the biological behavior of these products in tissue to enable them to respond to any safety concerns that their patients raise.

OBJECTIVES

To provide an overview of the metabolism of 1,4-butanediol diglycidyl ether (BDDE)-crosslinked hyaluronic acid (HA) dermal fillers and to examine the safety of the resulting byproducts.

METHODS

A review of available evidence was conducted.

RESULTS

After reaction with HA, the epoxide groups of BDDE are neutralized, and only trace amounts of unreacted BDDE remain in the product (<2 parts per million). When crosslinked HA, uncrosslinked HA, and unreacted BDDE degrade, they break down into harmless byproducts or into byproducts that are identical to substances already found in the skin.

CONCLUSION

Clinical and biocompatibility data from longer than 15 years support the favorable clinical safety profile of BDDE-crosslinked HA and its degradation products. Given the strength of the empirical evidence, physicians should be confident in offering these products to their patients.

Comprehensive screening of chymotrypsin C (CTRC) gene in tropical calcific pancreatitis identifies novel variants

OBJECTIVE

In a previous study, the authors have shown that rather than variants in trypsinogen gene(s), mutations in pancreatic secretory trypsin inhibitor (encoded by SPINK1) and cathepsin B (CTSB) are associated with tropical calcific pancreatitis (TCP). Recently, chymotrypsin C (CTRC) variants that diminish its activity or secretion were found to predict susceptibility to chronic pancreatitis (CP). The authors analysed CTRC variants in a large, ethnically matched case-control TCP cohort.

DESIGN

The authors sequenced all eight exons and flanking regions in CTRC in 584 CP patients (497 TCP, 87 idiopathic CP) and 598 normal subjects and analysed the significance of association using χ(2) test. The authors also investigated interaction of CTRC variants with p.N34S SPINK1 and p.L26V CTSB mutations.

RESULTS

The authors identified 14 variants in CTRC, of which non-synonymous variants were detected in 71/584 CP patients (12.2%) and 22/598 controls (3.7%; OR 3.62, 95% CI 2.21 to 5.93; p=6.2 × 10(-8)). Rather than the commonly reported p.K247_R254del variant in Caucasians, p.V235I was the most common mutation in Indian CP patients (28/575 (4.9%); OR 7.60, 95% CI 2.52 to 25.71; p=1.01 × 10(-5)). Another pathogenic variant, p.A73T was identified in 3.1% (18/584) patients compared with 0.3% (2/598) in controls (OR=9.48, 95% CI 2.19 to 41.03, p=2.5 × 10(-4)). The authors also observed significant association for the synonymous variant c.180C>T (p.(=)) with CP (OR 2.71, 95% CI 1.79 to 4.12, p=5.3 × 10(-7)). Two novel nonsense mutations, p.G242AfsX9 and p.W113X were also identified exclusively in CP patients. No interaction between CTRC variants and p.N34S SPINK1 or p.L26V CTSB mutations was observed.

CONCLUSION

This study on a large cohort of TCP patients provides evidence of allelic heterogeneity and confirms that CTRC variants play a significant role in its pathogenesis.

In silico ligand based design of indolylpiperidinyl derivatives as novel histamine H(1) receptor antagonists

Histamine H(1) receptor antagonists play a vital role in the first line treatment of a broad range of allergic diseases. Frequent dosing of the antagonist results in side effects like sedation and cardiovascular toxicity. The present study highlights the important structural requirement and mechanistic interpretation of novel indolylpiperidinyl derivatives as H(1) receptor antagonists so as to facilitate the design of newer antihistaminics with increased duration of action and comparatively reduced side effects. The significance of the developed quantitative structure-activity relationship (QSAR) models were evaluated on the basis of statistical values of square of correlation coefficient (r(2)); (multiple linear regression (MLR), 0.86; and partial least squares (PLS), 0.85). The predictive ability of the resulting QSAR models was evaluated with cross-validated correlation coefficient (r(2)cv) values (MLR, 0.82; PLS, 0.82) generated for the training set and r(2) values (MLR, 0.763; PLS, 0.855) derived for test set. The final models comprised of multidimensional steric (verloop length, verloop B(3)), electronic (total dipole moment) and steric (KAlpha1 index) descriptors. The study indicates that antihistaminic activity is largely explained by steric and electronic parameters. In line with parameters entered in the model some indolylpiperidines derivatives were designed with good antihistaminic properties and pharmacokinetic profiles.

Entrapment of ketorolac tromethamine in polymeric vehicle for controlled drug delivery

The most common method for applying a drug in to the eye is to formulate the drug in the form of an eye drop, but this method is not considered ideal for ocular delivery of drug because of poor bioavailability arising from precorneal loss processes, this loss of drug from the precorneal area is a net effect of drainage, tear secretion and noncorneal absorption. Following the above lead we tried to improve the ocular bioavailability by increasing the corneal contact time and the feasible way was to formulate a drug with mucoadhesive/viscosity imparting agents. The adhesive strength of various polymers on corneal surface was studied with the help of self modified Franz diffusion cell and freshly excised goat/bovine cornea. The polymers hydroxypropylmethylcellulose, carboxymethylcellulose sodium, Eudragit type E/RL/RS, Carbopol ETD 2020 and Carbopol 934 National Formulary were formulated with drug, ketorolac tromethamine. The adhesive strength of polymers on corneal surface and permeation characteristics of drug through cornea were investigated by using above said formulations. Eudragit type E/RL/RS did not show any improvement in mucoadhesion, but the formulations containing Carbopol ETD 2020 and Carbopol 934 national formulary showed good mucoadhesion on corneal surface in the concentration as low as 0.75%. The mucoadhesive strength was also evaluated using the combination of Carbopol acrylates/C 10-30 alkylacrylate with allylpentaerithrital and preservative benzalkonium chloride, which also resulted in good mucoadhesion with improved corneal permeation. Observations made in this study indicate the potentiality of the ophthalmic formulations containing mucoadhesive/viscosity imparting agents.

Assessing the pathological relevance of SPINK1 promoter variants

The SPINK1 gene, encoding the human pancreatic secretory trypsin inhibitor, is one of the major genes involved in predisposition to chronic pancreatitis (CP). In this study we have assessed the potential functional impact of 11 SPINK1 promoter variants by means of both luciferase reporter gene assay and electrophoretic mobility shift assay (EMSA), using human pancreatic COLO-357 cells as an expression system. The 11 promoter variants were found to be separable into three distinct categories on the basis of the reporter gene assay results viz loss-of-function, gain-of-function and functionally neutral. These findings, which were validated by EMSA, concurred with data from previous deletion studies and DNase I footprinting assays. Further, binding sites for two transcription factors, HNF1 and PTF1, were newly identified within the SPINK1 promoter by virtue of their being affected by specific variants. Combining the functional data with epidemiological data (derived by resequencing the SPINK1 promoter region in French, German and Indian CP patients and controls), then allowed us to make meaningful inferences as to each variant's likely contribution to CP. We conclude that only the three promoter variants associated with a loss-of-function (ie, −53C>T, −142T>C and −147A>G) are likely to be disease-predisposing alterations.

Ultrasound-enhanced drug transport and distribution in the brain

Drug delivery in the brain is limited by slow drug diffusion in the brain tissue. This study tested the hypothesis that ultrasound can safely enhance the permeation of drugs in the brain. In vitro exposure to ultrasound at various frequencies (85 kHz, 174 kHz, and 1 MHz) enhanced the permeation of tritium-labeled molecules with molecular weight up to 70 kDa across porcine brain tissue. A maximum enhancement of 24-fold was observed at 85 kHz and 1,200 J/cm². In vivo exposure to 1-MHz ultrasound further demonstrated the ability of ultrasound to facilitate molecule distribution in the brain of a non-human primate. Finally, ultrasound under conditions similar to those used in vivo was shown to cause no damage to plasmid DNA, siRNA, adeno-associated virus, and fetal rat cortical neurons over a range of conditions. Altogether, these studies demonstrate that ultrasound can increase drug permeation in the brain in vitro and in vivo under conditions that did not cause detectable damage.

One-step acquisition of functional biomolecules from tissues

Direct determination of functional biomolecular chemistry of clinically relevant tissues in vivo is a challenging task. Current approaches, based on tissue retrieval by biopsy and subsequent solubilization, are limited in terms of accurate representation of tissue constituents, reproducibility, and retention of functionality of solubilized tissue biomolecules. Using a pool of known surfactants, we designed and screened a large combinatorial library of surfactant formulations, which led to the discovery of rare synergistic formulations that greatly enhance tissue solubilization as well as preserve bioactivity of solubilized molecules, in particular proteins. By combining these formulations with a short ultrasound application, we developed a tissue sampling method--STAMP (Surfactant-based Tissue Acquisition for Molecular Profiling)--for rapid one-step determination of functional tissue chemistry in vivo. We specifically demonstrate STAMP-assisted profiling of a multitude of proteins, lipids, and genomic DNA in skin and mucosal tissues. Applications of this sampling methodology to rapid molecular diagnostics of cutaneous allergies and infectious diseases are also presented.

Genetic analysis of the glycoprotein 2 gene in patients with chronic pancreatitis

OBJECTIVES

The aim of this study was to evaluate whether variations in the glycoprotein 2 gene (GP2) may potentially affect the risk of chronic pancreatitis.

METHODS

Six hundred sixty-one French white patients (idiopathic chronic pancreatitis, n = 590; familial chronic pancreatitis, n = 42; hereditary pancreatitis, n = 29), 445 Dravidian patients from India (tropical calcific pancreatitis, n = 306; idiopathic chronic pancreatitis, n = 139), and 962 unrelated healthy subjects (French white, n = 500; Dravidian, n = 462) participated in this case-control association study. The entire coding sequence of the GP2 gene was searched for conventional genetic variations by direct sequencing, whereas all 12 exons of the GP2 gene were screened for copy number variations by quantitative fluorescent multiplex-polymerase chain reaction.

RESULTS

Only 3 rare missense mutations (p.A137T, p.E250D, and p.V432M; only p.E250D was not detected in any control subjects) and 3 common synonymous polymorphisms (c.348C>T, c.714G>C, and c.1275A>G) were identified. The c.348C>T and c.1275A>G variations were found to be contradictorily associated with the disease (ranging from protective effects to disease-predisposing effects) in the French white and Indian populations.

CONCLUSION

The paucity of patient-specific missense mutations and contradictory findings with respect to 2 common polymorphisms in the 2 contrasting populations suggest that the GP2 gene is unlikely to play a major role in the etiology of chronic pancreatitis.

Rapid sampling of molecules via skin for diagnostic and forensic applications

PURPOSE

Skin provides an excellent portal for diagnostic monitoring of a variety of entities; however, there is a dearth of reliable methods for patient-friendly sampling of skin constituents. This study describes the use of low-frequency ultrasound as a one-step methodology for rapid sampling of molecules from the skin.

METHODS

Sampling was performed using a brief exposure of 20 kHz ultrasound to skin in the presence of a sampling fluid. In vitro sampling from porcine skin was performed to assess the effectiveness of the method and its ability to sample drugs and endogenous epidermal biomolecules from the skin. Dermal presence of an antifungal drug-fluconazole and an abused substance, cocaine-was assessed in rats.

RESULTS

Ultrasonic sampling captured the native profile of various naturally occurring moisturizing factors in skin. A high sampling efficiency (79 +/- 13%) of topically delivered drug was achieved. Ultrasound consistently sampled greater amounts of drug from the skin compared to tape stripping. Ultrasonic sampling also detected sustained presence of cocaine in rat skin for up to 7 days as compared to its rapid disappearance from the urine.

CONCLUSIONS

Ultrasonic sampling provides significant advantages including enhanced sampling from deeper layers of skin and high temporal sampling sensitivity.

Therapeutic opportunities in biological responses of ultrasound

The therapeutic benefits of several existing ultrasound-based therapies such as facilitated drug delivery, tumor ablation and thrombolysis derive largely from physical or mechanical effects. In contrast, ultrasound can also trigger various time-dependent biochemical responses in the exposed biological milieu. Several biological responses to ultrasound exposure have been previously described in the literature but only a handful of these provide therapeutic opportunities. These include the use of ultrasound for healing of soft tissues and bones, the use of ultrasound for inducing non-necrotic tumor atrophy as well as for potentiation of chemotherapeutic drugs, activation of the immune system, angiogenesis and suppression of phagocytosis. A review of these therapeutic opportunities is presented with particular emphasis on their mechanisms. Overall, this review presents the increasing importance of ultrasound's role as a biological sensitizer enabling novel therapeutic strategies.

Low-frequency sonophoresis: current status and future prospects

Application of ultrasound enhances skin permeability to drugs, a phenomenon referred to as sonophoresis. Significant strides have been made in sonophoresis research in recent years, especially under low-frequency conditions (20 kHz<f<100 kHz). This article reviews the mechanistic principles and current status of sonophoresis under low-frequency conditions. Several therapeutic macromolecules including insulin, low-molecular weight heparin, and vaccines have been delivered using low-frequency sonophoresis in vivo. Clinical trials have been performed with several drugs including lidocaine and cyclosporin. Novel theoretical and experimental approaches have provided insights into the mechanisms of low-frequency sonophoresis. Current understanding of these mechanisms is presented.

Ultrasound-induced cavitation: applications in drug and gene delivery

Ultrasound, which has been conventionally used for diagnostics until recently, is now being extensively used for drug and gene delivery. This transformation has come about primarily due to ultrasound-mediated acoustic cavitation - particularly transient cavitation. Acoustic cavitation has been used to facilitate the delivery of small molecules, as well as macromolecules, including proteins and DNA. Controlled generation of cavitation has also been used for targeting drugs to diseased tissues, including skin, brain, eyes and endothelium. Ultrasound has also been employed for the treatment of several diseases, including thromboembolism, arteriosclerosis and cancer. This review provides a detailed account of mechanisms, current status and future prospects of ultrasonic cavitation in drug and gene delivery applications.

Low-frequency sonophoresis: ultrastructural basis for stratum corneum permeability assessed using quantum dots

Low-frequency sonophoresis (LFS) has been well documented to enhance the permeability of skin to macromolecular drugs via induction of localized transport regions. However, the organizational details of epidermis, specifically stratum corneum (SC), during sonophoresis are beyond the resolution limit of common histo-optical microscopy tools, which fail to reveal any notable structural alterations in these regions at a submicroscopic scale. Here we report, using quantum dots (QDs) as a tracer and confocal microscopy and transmission electron microscopy (TEM) (with OsO(4) and RuO(4) post-fixation) as visualization methods, on LFS-induced permeation pathways in the SC. QDs (20 nm diameter) penetrated well beyond the SC. TEM revealed that ultrasound significantly increased the frequency of occurrence of the otherwise scattered and separated lacunar spaces in the SC. A significant increase in lacunar dimensions was observed when 1% w/v sodium lauryl sulfate was added to the coupling medium. These studies show that LFS induces dilatation and higher connectivity of voids in the SC, possibly leading to formation of a three-dimensional porous network, which is capable of transporting QDs as well as macromolecules across the SC. This contention is consistent with previously conceived theoretical mechanistic understanding of LFS-induced enhanced transport across the skin.

Induction of cancer-specific cytotoxicity towards human prostate and skin cells using quercetin and ultrasound

Bioflavonoids, such as quercetin, have recently emerged as a new class of chemotherapeutic drugs for the treatment of various cancer types, but are marred by their low potency and poor selectivity. We report that a short application of low-frequency ultrasound selectively sensitises prostate and skin cancer cells against quercetin. Pretreatment of cells with ultrasound (20 kHz, 2 W cm⁻², 60 s) selectively induced cytotoxicity in skin and prostate cancer cells, while having minimal effect on corresponding normal cell lines. About 90% of the viable skin cancer cell population was lost within 48 h after ultrasound-quercetin (50 μM) treatment. Ultrasound reduced the LC₅₀ of quercetin for skin cancer cells by almost 80-fold, while showing no effect on LC₅₀ for nonmalignant skin cells.

Low-frequency ultrasound as a transcutaneous immunization adjuvant

Percutaneous vaccine delivery offers an advantageous mode of immunization due to the unique ability of cutaneous immune cells, especially Langerhans cells, to present antigens to the immune system. Langerhans cells, upon activation, migrate to the regional lymph nodes and lead to the generation of systemic and mucosal immune responses. However, simple topical application of vaccines does not deliver sufficient amounts of antigen in the skin to generate an adequate immune response. Co-administration of strong adjuvants such as cholera toxin or invasive skin abrasion is usually necessary to induce an adequate immune response by topical vaccine application. Here, we report on the use of low-frequency ultrasound as a potent physical adjuvant for successful transcutaneous immunization (TCI). Using tetanus toxoid as a model vaccine, we show that low-frequency ultrasound enhances the immune response induced by topical application of tetanus toxoid. The adjuvant effect of ultrasound is partly explained by the enhanced delivery of tetanus toxoid into the skin after ultrasound application and partly by the activation of immune cells after ultrasonic TCI. These studies demonstrate generation of a potent systemic immune response through TCI without using toxin adjuvants or skin abrasion. Ultrasonic TCI offers a needle-free and painless mode of immunization.

A novel 70-kDa Triton X-114-soluble antigen of Plasmodium falciparum that contains interspecies-conserved epitopes

In order to identify novel conserved integral membrane and other membrane-associated proteins of Plasmodium falciparum, lambda gt11-P. falciparum DNA library phages were immunoscreened with convalescent-phase mouse sera and rabbit antiserum against Triton X-114-soluble proteins of P. falciparum. One recombinant phage clone, L857, reacted with both of the antibody probes. Insert DNA (857 bp long) in L857 was 69% dA+dT rich and hybridized to a fragment of 1800 bp from mung bean nuclease-digested P. falciparum genomic DNA. The cloned parasite DNA did not show notable sequence homology with any known protein gene. The L857-encoded polypeptide, p34 (M(r) 34 kDa) was expressed in bacteria, fused to glutathione S-transferase (GST). The fusion peptide, GST-p34 (M(r) 62 kDa), was recognized by immune serum against Triton X-114-soluble antigens of P. falciparum and was reactive with anti-P. falciparum, anti-Plasmodium yoelii, and anti-GST sera. Rabbit antiserum raised against the fusion peptide recognized a 70-kDa protein from lysates of P. falciparum cells and a putative homologous 100-kDa protein from lysates of P. yoelii. The rabbit serum anti-fusion peptide antibodies bound to acetone-fixed P. falciparum-infected erythrocytes and, in immunofluorescent antibody tests, produced a punctate pattern of fluorescence suggesting that the 70-kDa native protein is associated with an apical organelle of the parasite.

Disulfide bond assignments and secondary structure analysis of human and murine interleukin 10

Interleukin 10 (IL-10), which was first discovered by its ability to inhibit the synthesis of various cytokines, most notably gamma interferon, from Th1 helper cells, displays pleiotropic immunoregulatory properties. Human and murine IL-10 have a high amino acid sequence identity (ca. 73%) which includes the conservation of all four cysteine residues in human IL-10 and the first four out of five cysteine residues for murine IL-10. Chemical analysis was used to determine that both recombinant human and recombinant murine IL-10 contain two disulfide bonds. The disulfide pairs for each were determined by mass spectrometric and reversed-phase HPLC analysis of trypsin-derived polypeptide fragments. The disulfide bond assignments for both species were similar in that the first cysteine residue in the sequence paired with the third and the second paired with the fourth. The fifth cysteine in murine IL-10 was determined by chemical modification to be unpaired. Far-UV circular dichroism analysis indicated that the secondary structure of recombinant human and murine IL-10 are composed of ca. 60% alpha-helix. Reduction of the disulfide bonds structurally destabilized the protein and led to a structure containing only 53% alpha-helix. The reduced protein displayed no in vitro biological activity in a mast cell proliferation assay. These studies indicate that IL-10 is a highly alpha-helical protein containing two disulfide bonds, either one or both of which are critical for its structure and function. In addition, these properties suggest that this interesting cytokine may belong to the alpha helical cytokine class of hematopoietic ligands.

A simple and sensitive spectrophotometric method for the quantitative determination of solid supported amino groups

A simple and sensitive method for the quantitative determination of free amino groups on solid support is described. This approach is a modification of Ngo's [(1986) J. Biochem. Biophys. Methods 12, 349-354] method reported earlier. The method is based on the reaction of the solid support with an excess of 5'-O-(4,4'-dimethoxytrityl)-thymidine-3'-O-(2,4-dinitrophenyl) succinate (DTDS) in the presence of a catalytic amount of 4-dimethylaminopyridine. After removing the excess reagent, solid support is treated with perchloric acid to release 4,4'-dimethoxytrityl cation into the solution. The released 4,4'-dimethoxytrityl cation, which has a strong absorption at 498 nm (epsilon 498 = 70,000), is then determined spectrophotometrically. A comparative study of DTDS, N-succinimidyl-3-(2-pyridyldithio)propionate and 4,4-dimethoxytrityl chloride is also included. The method was found to be very useful to determine those amino groups which are available for functionalization of solid supports, especially, monitoring the functionalization of solid supports for affinity chromatography and synthesis of biopolymers.