Biodegradable concanavalin A functionalized polycaprolactone nanoparticle: A promising avenue for cancer therapy

OBJECTIVE

Receptor-based tumor-selective delivery of therapeutic efficacy and therapeutic index of cytotoxic drugs that exhibit dose-limiting toxicity is observed. Concanavalin A (Con A) was selected as the ligand for the proposed system, which was appended to the polycaprolactone nanoparticles (NPs) carrying the drug to be a very efficient approach for the treatment of cancer.

METHODS

Preparation of plain polycaprolactone nanoparticles was carried out employing the emulsion diffusion evaporation technique. Con A was conjugated using carbodiimide chemistry by coupling -COOH group on the surface of nanoparticles. The paclitaxel-loaded Con A-conjugated nanoparticles were further subjected to the characterization of various parameters, that is, surface morphology, particle size, and polydispersity index. In vitro drug release study of both the formulations (plain & conjugated) was done using a dialysis tube up to 48 h in phosphate buffer (pH 7.4).

RESULTS

Studies done in xenograft models evidently propose a dose-dependent cytotoxicity response, that is, shrink in % cell growth with increase in the concentration of the drug. The fluorescence photomicrograph clearly revealed the access of the Con A-conjugated nanoparticles to the tumor. A noteworthy biodistribution difference of the paclitaxel from prepared systems was observed. At the same time, Con A-coupled nanoparticles increased the accumulation of paclitaxel in the tumor cells.

CONCLUSIONS

Hence, the Con A-conjugated nanoparticles formulation as compared to uncoupled solid lipid nanoparticles formulation and free drug solution showed nearly two times higher uptake because of the lectin receptors on the surface of tumors. Hence, it was envisaged to design polymeric nanoparticles which would be administered intravenously for better therapeutic efficacy.

An exhaustive comprehension of the role of herbal medicines in Pre- and Post-COVID manifestations

ETHNOPHARMACOLOGICAL RELEVANCE

The coronavirus disease (COVID-19) has relentlessly spread all over the world even after the advent of vaccines. It demands management, treatment, and prevention as well with utmost safety and effectiveness. It is well researched that herbal medicines or natural products have shown promising outcomes to strengthen immunity with antiviral potential against SARS-COV-2.

AIM OF THE REVIEW

Our objective is to provide a comprehensive insight into the preventive and therapeutic effects of herbal medicines and products (Ayurvedic) for pre-and post-COVID manifestations.

MATERIAL AND METHOD

The database used in the text is collected and compiled from Scopus, PubMed, Nature, Elsevier, Web of Science, bioRxiv, medRxiv, American Chemical Society, and clinicaltrials.gov up to January 2022. Articles from non-academic sources such as websites and news were also retrieved. Exploration of the studies was executed to recognize supplementary publications of research studies and systematic reviews. The keywords, such as "SARS-COV-2, coronavirus, COVID-19, herbal drugs, immunity, herbal immunomodulators, infection, herbal antiviral drugs, and WHO recommendation" were thoroughly searched. Chemical structures were drawn using the software Chemdraw Professional 15.0.0.160 (PerkinElmer Informatics, Inc.).

RESULT

A plethora of literature supports that the use of herbal regimens not only strengthen immunity but can also treat SARS-COV-2 infection with minimal side effects. This review summarizes the mechanistic insights into herbal therapy engaging interferons and antibodies to boost the response against SARS-COV-2 infection, several clinical trials, and in silico studies (computational approaches) on selected natural products including, Ashwagandha, Guduchi, Yashtimadhu, Tulsi, etc. as preventive and therapeutic measures against COVID. We have also emphasized the exploitation of herbal medicine-based pharmaceutical products along with perspectives for unseen upcoming alike diseases.

CONCLUSION

According to the current state of art and cutting-edge research on herbal medicines have showed a significant promise as modern COVID tools. Since vaccination cannot be purported as a long-term cure for viral infections, herbal/natural medicines can only be considered a viable alternative to current remedies, as conceived from our collected data to unroot recurring viral infections.

An Insight into Anticancer Bioactives from Punica granatum (Pomegranate)

Cancer is one of the major reasons for mortality across the globe. Side effects that are observed with the pharmacological medications present in the market majorly affect the quality of life of patients. This has caused the researchers to find an alternative source of medications such as herbal medicine which has shown a promising effect in anticancer treatment, one such source is Pomegranate, which belongs to the family Punicaceae. Several polyphenols are present in Punica granatum which exhibits properties ranging from antioxidant effect, antidiabetic effect, beneficial impact in treatment, and management of metabolic and cardiovascular disorders to advantageous impact in anticancer treatment. Polyphenols like punicalin, punicalagin, and ellagic acid are a few of the many compounds responsible for the anticancer activity of pomegranate. Many preparations of pomegranate such as Pomegranate Juice (PJ), Pomegranate seed oil (PSO), Pomegranate peel extract (PoPx) etc. are used in various clinical studies. These polyphenols show anticancer activity by either arresting the cell cycle in the G2/M phase, inducing apoptosis, or by damaging the DNA of tumor cells. This review explicitly discusses the role and mechanism of bioactives obtained from the pomegranate in the treatment and management of cancer. The chemical structure, properties and role of pomegranate in the treatment of breast, lung, thyroid, colon, and prostate cancer has been focused in detail. This review also discusses various drug delivery approaches for targeted delivery on tumors as well as patented preparation of pomegranate compounds along with the ongoing clinical trials.

Lipid-Based Nanocarriers for Lymphatic Transportation

The effectiveness of any drug is dependent on to various factors like drug solubility, bioavailability, selection of appropriate delivery system, and proper route of administration. The oral route for the delivery of drugs is undoubtedly the most convenient, safest and has been widely used from past few decades for the effective delivery of drugs. However, despite of the numerous advantages that oral route offers, it often suffers certain limitations like low bioavailability due to poor water solubility as well as poor permeability of drugs, degradation of the drug in the physiological pH of the stomach, hepatic first-pass metabolism, etc. The researchers have been continuously working extensively to surmount and address appropriately the inherent drawbacks of the oral drug delivery. The constant and continuous efforts have led to the development of lipid-based nano drug delivery system to overcome the aforesaid associated challenges of the oral delivery through lymphatic transportation. The use of lymphatic route has demonstrated its critical and crucial role in overcoming the problem associated and related to low bioavailability of poorly water-soluble and poorly permeable drugs by bypassing intestinal absorption and possible first-pass metabolism. The current review summarizes the bonafide perks of using the lipid-based nanocarriers for the delivery of drugs using the lymphatic route. The lipid-based nanocarriers seem to be a promising delivery system which can be optimized and further explored as an alternative to the conventional dosage forms for the enhancement of oral bioavailability of drugs, with better patient compliance, minimum side effect, and improved the overall quality of life.

Nanocarrier-Based Combination Chemotherapy for Resistant Tumor: Development, Characterization, and Ex Vivo Cytotoxicity Assessment

A folic acid-conjugated paclitaxel (PTX)-doxorubicin (DOX)-loaded nanostructured lipid carrier(s) (FA-PTX-DOX NLCs) were prepared by using emulsion-evaporation method and extensively characterized for particle size, polydispersity index, zeta potential, and % entrapment efficiency which were found to be 196 ± 2.5 nm, 0.214 ± 0.04, +23.4 ± 0.3 mV and 88.3 ± 0.2% (PTX), and 89.6 ± 0.5% (DOX) respectively. In vitro drug release study of optimized formulation was carried out using dialysis tube method. FA-conjugated PTX-DOX-loaded NLCs showed 75.6 and 78.4% (cumulative drug release) of PTX and DOX respectively in 72 h in PBS (pH 7.4)/methanol (7:3), while in the case of FA-conjugated PTX-DOX-loaded NLCs, cumulative drug release recorded was 80.4 and 82.8% of PTX and DOX respectively in 72 h in PBS (pH 4.0)/methanol (7:3). Further, the formulation(s) were evaluated for ex vivo cytotoxicity study. The cytotoxicity assay in doxorubicin-resistant human breast cancer MCF-7/ADR cell lines revealed lowest GI₅₀ value of FA-D-P NLCs which was 1.04 ± 0.012 μg/ml, followed by D-P NLCs and D-P solution with GI₅₀ values of 3.12 ± 0.023 and 3.89 ± 0.007 μg/ml, respectively. Findings indicated that the folic acid-conjugated PTX and DOX co-loaded NLCs exhibited lower GI₅₀ values as compared to unconjugated PTX and DOX co-loaded NLCs; thus, they have relatively potential anticancer efficacy against resistant tumor.

C-Type lectin receptor(s)-targeted nanoliposomes: an intelligent approach for effective cancer immunotherapy

Aim: The purpose of present approach is to target C-Type lectin (CTL) receptors for preferential uptake by the macrophages/dendritic cells and improving the cross-presentation of ovalbumin. Materials & methods: Conventional and engineered nanoliposomes (MPNLs) were fabricated and extensively characterized. The nanoliposome(s) was spherical in shape; and their ζ potential, size and ovalbumin loading efficiency were recorded to be 268 ± 4.15 nm, 23.4 ± 0.35 mV, 46.65 ± 1.84%, respectively. Results: The findings demonstrate that MPNLs significantly improved the antigen uptake and its cross-presentation to evoke Th CD8+ cell-mediated cellular immunity. Conclusion: In a nutshell, this engineered approach mannose surface modification for active targeting to dendritic cells/macrophages and pH-dependent quick endosomal antigen release is a promising system for efficient cancer immunotherapy.

Myeloid protein tyrosine phosphatase 1B (PTP1B) deficiency protects against atherosclerotic plaque formation in the ApoE-/- mouse model of atherosclerosis with alterations in IL10/AMPKα pathway

Objective

Cardiovascular disease (CVD) is the most prevalent cause of mortality among patients with Type 1 or Type 2 diabetes, due to accelerated atherosclerosis. Recent evidence suggests a strong link between atherosclerosis and insulin resistance due to impaired insulin receptor (IR) signaling. Moreover, inflammatory cells, in particular macrophages, play a key role in pathogenesis of atherosclerosis and insulin resistance in humans. We hypothesized that inhibiting the activity of protein tyrosine phosphatase 1B (PTP1B), the major negative regulator of the IR, specifically in macrophages, would have beneficial anti-inflammatory effects and lead to protection against atherosclerosis and CVD.

Methods

We generated novel macrophage-specific PTP1B knockout mice on atherogenic background (ApoE^−/−/LysM-PTP1B). Mice were fed standard or pro-atherogenic diet, and body weight, adiposity (echoMRI), glucose homeostasis, atherosclerotic plaque development, and molecular, biochemical and targeted lipidomic eicosanoid analyses were performed.

Results

Myeloid-PTP1B knockout mice on atherogenic background (ApoE^−/−/LysM-PTP1B) exhibited a striking improvement in glucose homeostasis, decreased circulating lipids and decreased atherosclerotic plaque lesions, in the absence of body weight/adiposity differences. This was associated with enhanced phosphorylation of aortic Akt, AMPKα and increased secretion of circulating anti-inflammatory cytokine interleukin-10 (IL-10) and prostaglandin E2 (PGE₂), without measurable alterations in IR phosphorylation, suggesting a direct beneficial effect of myeloid-PTP1B targeting.

Conclusions

Here we demonstrate that inhibiting the activity of PTP1B specifically in myeloid lineage cells protects against atherosclerotic plaque formation, under atherogenic conditions, in an ApoE^−/− mouse model of atherosclerosis. Our findings suggest for the first time that macrophage PTP1B targeting could be a therapeutic target for atherosclerosis treatment and reduction of CVD risk.

•

PTP1B inhibition as therapy for atherosclerosis/cardiovascular disease is proposed.

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Myeloid-PTP1B mice on ApoE^−/− background (ApoE^−/−/LysM-PTP1B) were generated.

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ApoE^−/−/LysM-PTP1B had improved glucose homeostasis with no body weight differences.

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ApoE^−/−/LysM-PTP1B had lower lipids and protection against atherosclerotic plaques.

•

Protection was via a PGE₂/IL-10/AMPKα mechanism.

Glycyrrhizin Conjugated Dendrimer and Multi-Walled Carbon Nanotubes for Liver Specific Delivery of Doxorubicin

The purpose of the present investigation was to investigate the drug targeting potential of glycyrrhizin (GL) conjugated dendrimers (GL-PPI) and multi walled carbon nanotubes (GL-MWCNTs) towards liver targeting of a model anti-cancer agent, doxorubicin (DOX). The synthesis was confirmed by FTIR, 1H-NMR and morphology analysis. Higher DOX loading was observed in case of GL-PPI-DOX and GL-MWCNT-DOX (43.02 ± 0.64% and 87.26 0.57%, respectively) than parent nanocarriers. GL attachment considerably reduced the haemolytic toxicity of DOX by 12.38 ± 1.05 and 7.30 ± 0.63% by GL-PPI-DOX and GL-MWCNT-DOX, respectively. MTT cytotoxicity studies, flow cytometry and cell morphology assessment was done in HepG2 cell. The IC50 of DOX was reduced from 4.19±0.05 µM to 2.0±0.01 and 2.7±0.03 µM, respectively by GL-PPI-DOX and GL-MWCNT-DOX, respectively. Flow cytometry and phase contrast microscopy confirmed GL conjugated formulations to be significantly dragging higher cancer cell number of cells in early apoptosis as well as in early apoptotic phase.

Polymer nanotechnology based approaches in mucosal vaccine delivery: challenges and opportunities

Mucosal sites serve as the main portal for the entry of pathogens and thus immunization through mucosal routes can greatly improve the immunity. Researchers are continuously exploring the vaccination strategies to engender protective mucosal immune responses. Unearthing of mucosal adjuvants, that are safe and effective, is enhancing the magnitude and quality of the protective immune response. Use of nanotechnology based polymeric nanocarrier systems which encapsulate vaccine components for protection of sensitive payload, incorporate mucosal adjuvants to maximize the immune responses and target the mucosal immune system is a key strategy to improve the effectiveness of mucosal vaccines. These advances promise to accelerate the development and testing of new mucosal vaccines against many human diseases. This review focuses on the need for the development of nanocarrier based mucosal vaccines with emphases on the polymeric nanoparticles, their clinical status and future perspectives. This review focuses on the need and new insights for the development of nanoarchitecture governed mucosal vaccination with emphases on the various polymeric nanoparticles, their clinical status and future perspectives.

Regulation of growth hormone induced JAK2 and mTOR signalling by hepatic protein tyrosine phosphatase 1B

Protein tyrosine phosphatase 1B (PTP1B) regulates various signalling pathways including insulin, leptin, IGF-1 and growth hormone (GH) signalling. Transmission of the GH signal depends on Janus kinase 2 (JAK2), which is how PTP1B is thought to modulate GH signalling in the liver, based on studies utilising global PTP1B knockout mice (Ptp1b(-/-)). Here, we investigated the liver-specific role of PTP1B in GH signalling, using liver-specific Ptp1b(-/-) mice (alb-crePtp1b(-/-)), under physiological (chow) or insulin resistant (high-fat diet [HFD]) feeding conditions. Body weight and adiposity were comparable between female alb-crePtp1b(-/-) and Ptp1b(fl/fl) control mice. On chow diet, under 48-hour fasting GH-resistant conditions, GH stimulation in vivo led to a robust stimulation of the JAK-STAT signalling pathway. Alb-crePtp1b(-/-) mice exhibited significantly higher GH-induced JAK2 phosphorylation and SOCS3 gene expression post-GH stimulation. However, STAT3, STAT5 and ERK1/2 phosphorylation and SOCS2 gene expression were similar between groups. Interestingly, GH-induced mTOR phosphorylation was significantly higher in alb-crePtp1b(-/-) mice 5-min post-GH stimulation compared to controls, revealing this part of the pathway under direct control of PTP1B. Under ad lib HFD-fed conditions, GH-induced STAT5 phosphorylation significantly increased in alb-crePtp1b(-/-) mice only, with no alterations in the controls. Overall, our data demonstrate that liver-specific PTP1B deletion leads to significant alterations in GH signalling with increased JAK2, STAT5 and mTOR phosphorylation and SOCS3 gene expression.

Dendrimer, liposomes, carbon nanotubes and PLGA nanoparticles: one platform assessment of drug delivery potential

Liposomes (LIP), nanoparticles (NP), dendrimers (DEN), and carbon nanotubes (CNTs), represent eminent classes of drug delivery devices. A study was carried out herewith by employing docetaxel (DTX) as model drug to assess their comparative drug delivery potentials. Under optimized conditions, highest entrapment of DTX was observed in CNT-based formulation (DTX-CNTs, 74.70 ± 4.9%) followed by nanoparticles (DTX-NP, 62.34 ± 1.5%), liposome (49.2 ± 1.51%), and dendrimers (28.26 ± 1.74%). All the formulations were found to be of nanometric size. In vitro release studies were carried out in PBS (pH 7.0 and 4.0), wherein all the formulations showed biphasic release pattern. Cytotoxicity assay in human cervical cancer SiHa cells inferred lowest IC50 value of 1,235.09 ± 41.93 nM with DTX-CNTs, followed by DTX-DEN, DTX-LIP, DTX-NP with IC50 values of 1,571.22 ± 151.27, 1,653.98 ± 72.89, 1,922.75 ± 75.15 nM, respectively. Plain DTX showed higher hemolytic toxicity of 22.48 ± 0.94%, however loading of DTX inside nanocarriers drastically reduced its hemolytic toxicity (DTX-DEN, 17.22 ± 0.48%; DTX-LIP, 4.13 ± 0.19%; DTX-NP, 6.43 ± 0.44%; DTX-CNTs, 14.87 ± 1.69%).

Inducible liver-specific knockdown of protein tyrosine phosphatase 1B improves glucose and lipid homeostasis in adult mice

AIMS/HYPOTHESIS

Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of insulin signalling. Hepatic PTP1B deficiency, using the Alb-Cre promoter to drive Ptp1b deletion from birth in mice, improves glucose homeostasis, insulin sensitivity and lipid metabolism. The aim of this study was to investigate the therapeutic potential of decreasing liver PTP1B levels in obese and insulin-resistant adult mice.

METHODS

Inducible Ptp1b liver-specific knockout mice were generated using SA-Cre-ER(T2) mice crossed with Ptp1b floxed (Ptp1b(fl/fl)) mice. Mice were fed a high-fat diet (HFD) for 12 weeks to induce obesity and insulin resistance. Tamoxifen was administered in the HFD to induce liver-specific deletion of Ptp1b (SA-Ptp1b(-/-) mice). Body weight, glucose homeostasis, lipid homeostasis, serum adipokines, insulin signalling and endoplasmic reticulum (ER) stress were examined.

RESULTS

Despite no significant change in body weight relative to HFD-fed Ptp1b(fl/fl) control mice, HFD-fed SA-Ptp1b(-/-) mice exhibited a reversal of glucose intolerance as determined by improved glucose and pyruvate tolerance tests, decreased fed and fasting blood glucose and insulin levels, lower HOMA of insulin resistance, circulating leptin, serum and liver triacylglycerols, serum NEFA and decreased HFD-induced ER stress. This was associated with decreased glycogen synthase, eukaryotic translation initiation factor-2α kinase 3, eukaryotic initiation factor 2α and c-Jun NH2-terminal kinase 2 phosphorylation, and decreased expression of Pepck.

CONCLUSIONS/INTERPRETATION

Inducible liver-specific PTP1B knockdown reverses glucose intolerance and improves lipid homeostasis in HFD-fed obese and insulin-resistant adult mice. This suggests that knockdown of liver PTP1B in individuals who are already obese/insulin resistant may have relatively rapid, beneficial therapeutic effects.

Susceptibility to diet-induced obesity and glucose intolerance in the APP (SWE)/PSEN1 (A246E) mouse model of Alzheimer's disease is associated with increased brain levels of protein tyrosine phosphatase 1B (PTP1B) and retinol-binding protein 4 (RBP4), and basal phosphorylation of S6 ribosomal protein

AIMS/HYPOTHESIS

Obesity is a major risk factor for development of insulin resistance, a proximal cause of type 2 diabetes and is also associated with an increased relative risk of Alzheimer's disease. We therefore investigated the susceptibility of transgenic mice carrying human mutated transgenes for amyloid precursor protein (APP (SWE)) and presenilin 1 (PSEN1 (A246E)) (APP/PSEN1), or PSEN1 (A246E) alone, which are well-characterised animal models of Alzheimer's disease, to develop obesity, glucose intolerance and insulin resistance, and whether this was age- and/or diet-dependent.

METHODS

We analysed the effects of age and/or diet on body weight of wild-type, PSEN1 and APP/PSEN1 mice. We also analysed the effects of diet on glucose homeostasis and insulin signalling in these mice.

RESULTS

While there were no body weight differences between 16-17- and 20-21-month-old PSEN1 mice, APP/PSEN1 mice and their wild-type controls on standard, low-fat, chow diet, the APP/PSEN1 mice still exhibited impaired glucose homeostasis, as investigated by glucose tolerance tests. This was associated with increased brain protein tyrosine phosphatase 1B protein levels in APP/PSEN1 mice. Interestingly, short-term high-fat diet (HFD) feeding of wild-type, PSEN1 and APP/PSEN1 mice for a period of 8 weeks led to higher body weight gain in APP/PSEN1 than in PSEN1 mice and wild-type controls. In addition, HFD-feeding caused fasting hyperglycaemia and worsening of glucose maintenance in PSEN1 mice, the former being further exacerbated in APP/PSEN1 mice. The mechanism(s) behind this glucose intolerance in PSEN1 and APP/PSEN1 mice appeared to involve increased levels of brain retinol-binding protein 4 and basal phosphorylation of S6 ribosomal protein, and decreased insulin-stimulated phosphorylation of Akt/protein kinase B and extracellular signal-regulated kinase 1/2 in the brain.

CONCLUSIONS/INTERPRETATION

Our results indicate that Alzheimer's disease increases susceptibility to body weight gain induced by HFD, and to the associated glucose intolerance and insulin resistance.

Oxidative stress modulates osteoblastic differentiation of vascular and bone cells

Oxidative stress may regulate cellular function in multiple pathological conditions, including atherosclerosis. One feature of the atherosclerotic plaque is calcium mineral deposition, which appears to result from the differentiation of vascular osteoblastic cells, calcifying vascular cells (CVC). To determine the role of oxidative stress in regulating the activity of CVC, we treated these cells with hydrogen peroxide (H(2)O(2)) or xanthine/xanthine oxidase (XXO) and assessed their effects on intracellular oxidative stress, differentiation, and mineralization. These agents increased intracellular oxidative stress as determined by 2,7 dichlorofluorescein fluorescence, and enhanced osteoblastic differentiation of vascular cells, based on alkaline phosphatase activity and mineralization. In contrast, H(2)O(2) and XXO resulted in inhibition of differentiation markers in bone osteoblastic cells, MC3T3-E1, and marrow stromal cells, M2-10B4, while increasing oxidative stress. In addition, minimally oxidized low-density lipoprotein (MM-LDL), previously shown to enhance vascular cell and inhibit bone cell differentiation, also increased intracellular oxidative stress in the three cell types. These effects of XXO and MM-LDL were counteracted by the antioxidants Trolox and pyrrolidinedithiocarbamate. These results suggest that oxidative stress modulates differentiation of vascular and bone cells oppositely, which may explain the parallel buildup and loss of calcification, seen in vascular calcification and osteoporosis, respectively.

Effects of MAP kinase cascade inhibitors on the MKK5/ERK5 pathway

Antibodies that recognise the active phosphorylated forms of mitogen-activated protein kinase (MAPK) kinase 5 (MKK5) and extracellular signal-regulated kinase 5 (ERK5) in untransfected cells have been exploited to show that the epidermal growth factor (EGF)-induced activation of MKK5 and ERK5 occurs subsequent to the activation of ERK1 and ERK2 in HeLa cells. The drugs U0126 and PD184352, which prevent the activation of MKK1 (and hence the activation of ERK1/ERK2), also prevent the activation of MKK5, although higher concentrations are required. Our studies define physiological targets of the MKK5/ERK5 pathway as proteins whose phosphorylation is largely prevented by 10 microM PD184352, but unaffected by 2 microM PD184352. Surprisingly, 2 microM PD184352 prolongs the activation of MKK5 and ERK5 induced by EGF or H(2)O(2), indicating negative control of the MKK5/ERK5 pathway by the classical MAPK cascade. Our results also indicate that ERK5 is not a significant activator of MAPK-activated protein kinase-1/RSK in HeLa cells.

Regulation of vascular calcification in atherosclerosis

Over a century ago it was recognized that the vessel wall is a predominant site for ectopic calcification which is a hallmark of clinically significant atherosclerotic lesions. Old observational studies, which characterized vascular calcification as osteogenesis, and recent identification of common molecular mechanisms in bone and vascular calcification have led to the new recognition that atherosclerotic calcification is an actively regulated process similar to osteogenesis and distinct from a metastatic passive mineralization. Since the atherosclerotic lesion is composed of a multitude of cells and inflammatory mediators, elucidation of the role of these components in induction and acceleration of calcification is of fundamental importance in better understanding its pathogenesis and identifying possible interventional targets. This article will focus on four important mediators of vascular calcification: 1) calcifying vascular cells, 2) oxidized lipids, 3) cytokines, and 4) leptin.

Inhibition of N-linked glycosylation of the human type 1alpha metabotropic glutamate receptor by tunicamycin: effects on cell-surface receptor expression and function

The potential role of N-linked glycosylation of the human type 1alpha metabotropic glutamate (mGlu1alpha) receptor was studied in a recombinant, inducible expression system, where receptor expression was induced in the absence and presence of tunicamycin. In the absence of tunicamycin the mGlu1alpha receptor appeared to be expressed, at least in part, as a dimer consisting of monomers of approx. 145 and 160 KDa relative molecular mass (Mr). In the presence of tunicamycin only a single monomeric protein could be detected approximating the Mr predicted for the human mGlu1alpha receptor based on its primary amino acid sequence (130 KDa). Exposure to tunicamycin during receptor induction did not appear to affect the cell surface expression of the mGlu1alpha receptor as determined immunocytochemically or using a cell-surface biotinylation strategy, but reduced agonist-stimulated phosphoinositide hydrolysis by approximately 50% compared to control cell populations. Our data suggest that non-N-glycosylated human mGlu1alpha receptors can traffic to the cell surface and activate phospholipase C.

Molecular cloning of Proteus mirabilis uroepithelial cell adherence (uca) genes

Proteus mirabilis bacteria are a common cause of hospital-acquired urinary tract infection. In a previous study, we described a P. mirabilis fimbrial protein, UCA, that adhered to human uroepithelial cells. Genes sufficient for expression of UCA adherence were cloned into Escherichia coli K-12. E. coli bacteria that contained the uca recombinant plasmid adhered to human uroepithelial cells. In addition, the ucaA gene encoding the structural component of UCA pili was subcloned, and its DNA sequence was determined. Amino acid sequence homology (30 to 50%) was found between mature UcaA protein and pilins from pathogenic bacteria representing several genera, including E. coli F17, G, and type 1C pilins, Haemophilus M43 pilin, and a Bordetella pilin.

In vitro toxicity testing for antibacterials against human keratinocytes

The use of cultured human keratinocytes in an in vitro comparison of topical antibacterial toxicity for epithelial cells was examined. The complement of three assessments allows testing of epithelial migration, growth, and survival. The three assessments included (1) flow cytometry for determination of cell survival, (2) a comparison of confluent cell culture growth after antibacterial exposures, and (3) an evaluation of cell migration using a technique of dermal explants to study radial migration. A comparative ranking of the toxicities of the various topical antibacterials was determined with the three assessments. This has confirmed anecdotal reports that many of the topical antibacterials are cell-toxic and may inhibit wound healing. This information can be directly extrapolated to the clinical setting, unlike many of the animal data for wound healing that currently exist.

Treatment of intractable pruritus ani

The majority of patients with idiopathic pruritus ani respond favorably to conservative treatment. Moreover, response to specific medical therapy is almost always favorable in certain dermatologic diseases such as psoriasis, mycotic dermatitis, and contact dermatitis. When surgery is performed for anorectal disorders such as hemorrhoids and fistulas, or potentially malignant entities such as extramammary Paget's disease, the accompanying pruritus ani invariably improves as well. Only patients with chronic intractable pruritus ani are included in the current study. Methylene blue (methylthionine chloride) 0.5 percent is injected intracutaneously on the anodermal and perianal skin. With one treatment, long-term cure has been observed.

Effect of arteriovenous flow reversal on blood flow and metabolism in a skin flap

Twelve pig buttock island flaps (10 X 10 cm) were studied for 6 hours after arteriovenous flow reversal at the level of the pedicle. Follow-up was 48 hours. Blood pressure, Po2, pH, and lactate were measured in flap arteries and veins. Oxygen consumption was calculated. Data indicated true flow reversal. Blood pressure and Po2 in flap veins increased to systemic arterial levels. Outflow was provided by the arterial system, demonstrating venous pressure and Po2 values. Lactate increased significantly (1.8 +/- 0.5 to 4.0 +/- 2.3 mmol/liter), while pH dropped from 7.43 +/- 0.03 to 7.11 +/- 0.02. Oxygen consumption remained below baseline. In four flaps thrombosis occurred within 6 hours; no flap survived 48 hours. The results of this study do not encourage clinical application of the concept of flow reversal.