Experimental and Theoretical Investigations of Solvation Dynamics of Ionic Fluids: Appropriateness of Dielectric Theory and the Role of DC Conductivity

An analysis is provided of the subnanosecond dynamic solvation of ionic liquids in particular and ionic solutions in general. It is our hypothesis that solvation relaxation in ionic fluids, in the nonglassy and nonsupercooled regimes, can be understood rather simply in terms of the dielectric spectra of the solvent. This idea is suggested by the comparison of imidazolium ionic liquids with their pure organic counterpart, butylimidazole (J. Phys. Chem. B 2004, 108, 10245-10255). It is borne out by a calculation of the solvation correlation time from frequency dependent dielectric data for the ionic liquid, ethylammonium nitrate, and for the electrolyte solution of methanol and sodium perchlorate. Very good agreement is obtained between these theoretically calculated solvation relaxation functions and those obtained from fluorescence upconversion spectroscopy. Our comparisons suggest that translational motion of ions may not be the predominant factor in short-time solvation of ionic fluids and that many tools and ideas about solvation dynamics in polar solvents can be adapted to ionic fluids.

Immune Responses to Asexual Blood-Stages of Malaria Parasites

The blood stage of the malaria parasite's life cycle is responsible for all the clinical symptoms of malaria. The development of clinical disease is dependent on the interplay of the infecting parasite with the immune status and genetic background of the host. Following repeated exposure to malaria parasites, individuals residing in endemic areas develop immunity. Naturally acquired immunity provides protection against clinical disease, especially severe malaria and death from malaria, although sterilizing immunity is never achieved. Given the absence of antigen processing in erythrocytes, immunity to blood stage malaria parasites is primarily conferred by humoral immune responses. Cellular and innate immune responses play a role in controlling parasite growth but may also contribute to malaria pathology. Here, we analyze the natural humoral immune responses acquired by individuals residing in P. falciparum endemic areas and review their role in providing protection against malaria. In addition, we review the dual potential of cellular and innate immune responses to control parasite multiplication and promote pathology.

MR imaging, MR spectroscopy, and diffusion tensor imaging of sequential studies in neonates with encephalopathy

BACKGROUND

Although the imaging, spectroscopic, and diffusion characteristics of brains of infants with neonatal encephalopathy have been described, the time course during which these changes evolve is not clear. The results of sequential MR imaging studies--including anatomic MR imaging, proton MR spectroscopy, and diffusion tensor imaging (DTI)--of 10 patients enrolled prospectively in a study of neonatal encephalopathy are reported to help to clarify the time course of changes in different brain regions during the first 2 weeks of life.

METHODS

Ten neonates were prospectively enrolled in a study of the evolution of MR findings in neonatal encephalopathy and were studied 2 (8 patients) or 3 (2 patients) times within the first 2 weeks of life. The MR examination included spin-echo T1 and T2-weighted images, DTI, and long echo time (288 milliseconds) proton MR spectroscopy. Diffusion parameters (diffusivity [D(av)], fractional anisotropy [FA], and individual eigenvalues) were calculated for 10 1-cm2 regions of interest in each hemisphere that were placed based on anatomic landmarks. D(av) and FA were then measured manually in the same areas on a workstation. Metabolite ratios (NAA/Ch, Cr/Ch, Cr/NAA, Lac/Ch, and Lac/NAA) were calculated in 7 regions of interest. Imaging appearance, diffusion parameters, and metabolite ratios were then evaluated longitudinally (comparing with other studies on the same patient at different times) and cross-sectionally (comparing all studies performed on the same postnatal day).

RESULTS

In most of the patients a characteristic evolution of DTI and MR spectroscopy parameters was seen during the first 2 weeks after birth. Although the anatomic images were normal or nearly normal on the first 2 days after birth in most patients, abnormalities were detected on DTI (both visually and by quantitative interrogation of D(av) maps) and proton MR spectroscopy (abnormal metabolite ratios). These parameters tended to worsen until about day 5 and then normalize, though in several patients abnormal metabolite ratios persisted. Of interest, as areas of abnormal diffusivity pseudonormalized within one region of the brain they would develop in other areas. Therefore, the pattern of injury looked very different when imaging was performed at different times during this evolution.

CONCLUSION

Patterns of injury detected by standard anatomic imaging sequences, DTI sequences, and proton MR spectroscopy varied considerably during the first 2 weeks after injury. The appearance of new areas of reduced diffusion simultaneous with the pseudonormalization of areas that had reduced diffusion at earlier times can result in an entirely different pattern of injury on diffusivity maps acquired at different time points. Awareness of these evolving patterns is essential if studies are performed and interpreted during this critical period of time.

Leech bite: a rare gynecologic emergency

Vaginal bleeding as the result of a leech bite is a rare occurrence. We report 2 cases of vaginal bleeding in young girls that resulted from a leech bite and required treatment. Clinical presentation and management for young girls is described. Health professionals working in rural areas where leech infestation is common should be aware that children are at risk for leech bites in the genital region; a high index of suspicion is of great help to make an early diagnosis and ensure prompt treatment.

Interaction of Glutathione S-Transferase with Hypericin: A Photophysical Study

The photophysics of hypericin have been studied in its complex with two different isoforms, A1-1 and P1-1, of the protein glutathione S-transferase (GST). One molecule of hypericin binds to each of the two GST subunits. Comparisons are made with our previous results for the hypericin/human serum albumin complex (Photochem. Photobiol. 1999, 69, 633-645). Hypericin binds with high affinity to the GSTs: 0.65 microM for the A1-1 isoform and 0.51 microM for the P1-1 isoform (Biochemistry 2004, 43, 12761-12769). The photophysics and activity of hypericin are strongly modulated by the binding protein. Intramolecular hydrogen-atom transfer is suppressed in both cases. Most importantly, while there is significant singlet oxygen generation from hypericin bound to GST A1-1, binding to GST P1-1 suppresses singlet oxygen generation to almost negligible levels. The data are rationalized in terms of a simple model in which the hypericin photophysics depends entirely upon the decay of the triplet state by two competing processes, quenching by oxygen to yield singlet oxygen and ionization, the latter of these two are proposed to be modulated by A1-1 and P1-1.

Tumour necrosis factor receptor gene therapy affects cellular immune responses in collagen induced arthritis in mice

BACKGROUND

Collagen induced arthritis (CIA) is an animal model of rheumatoid arthritis (RA) amenable to immunotherapy directed against tumour necrosis factor alpha (TNFalpha).

OBJECTIVE

To evaluate whether local TNF receptor (TNF-R) gene therapy in DBA/1 mice exerts an influence beyond anti-inflammatory effects. Two measures of CIA pathogenesis were investigated-namely, immunity to collagen II (CII) 245-270 peptide (the major immunodominant epitope within bovine CII) and the preferential activation of T cell Vbeta8.2 variable region receptors in arthritic DBA/1 mice.

METHODS

DBA/1 mice received single periarticular injections of media or retroviral vectors containing LacZ or human TNF-R into affected arthritic paws at disease onset. Disease severity was monitored, immune responses towards the immunodominant bovine CII 245-270 and subdominant CII 334-360 peptide epitopes were assessed by ELISA, and T cell Vbeta usage was analysed by real time polymerase chain reaction for the LacZ transduced, TNF-R, and viral-free media treated control animals. The therapeutic influence of TNF-R gene transduction was compared with other groups at different times after treatment.

RESULTS

Reduced disease severity was seen 15-35 days after treatment, with a concomitant increase in immunity towards the subdominant CII 334-360 peptide epitope rather than the immunodominant CII 245-270 peptide in TNF-R treated animals. Early in the disease, TNF-R treated animals demonstrated a reduction of bias towards the otherwise predominant Vbeta8.2 T cell subset.

CONCLUSIONS

TNF-R gene therapy influences cellular immunity in CIA, leading to overall disease amelioration, thus suggesting that TNF inhibition may have therapeutic potential beyond the control of inflammation in RA.

Scaling behavior of the Portevin-Le Chatelier effect in an Al-2.5%Mg alloy

The scaling behavior of the Portevin-Le Chatelier (PLC) effect was studied by deforming an Al-2.5%Mg alloy for a wide range of strain rates. To reveal the exact scaling nature, the time series data of true stress versus time, obtained during deformation, were analyzed by two complementary methods: the finite variance scaling method and the diffusion entropy analysis. From these analyses we could establish that, in the entire span of strain rates, the PLC effect showed the Levy-walk property.

Human hepatic stellate cell lines, LX-1 and LX-2: new tools for analysis of hepatic fibrosis

BACKGROUND

Hepatic stellate cells (HSCs) are a major fibrogenic cell type that contributes to collagen accumulation during chronic liver disease. With increasing interest in developing antifibrotic therapies, there is a need for cell lines that preserve the in vivo phenotype of human HSCs to elucidate pathways of human hepatic fibrosis. We established and characterised two human HSC cell lines termed LX-1 and LX-2, and compared their features with those of primary human stellate cells.

METHODS AND RESULTS

LX-1 and LX-2 were generated by either SV40 T antigen immortalisation (LX-1) or spontaneous immortalisation in low serum conditions (LX-2). Both lines express alpha smooth muscle actin, vimentin, and glial fibrillary acid protein, as visualised by immunocytochemistry. Similar to primary HSCs, both lines express key receptors regulating hepatic fibrosis, including platelet derived growth factor receptor beta (betaPDGF-R), obese receptor long form (Ob-RL), and discoidin domain receptor 2 (DDR2), and also proteins involved in matrix remodelling; matrix metalloproteinase (MMP)-2, tissue inhibitor of matrix metalloproteinase (TIMP)-2, and MT1-MMP, as determined by western analyses. LX-2 have reduced expression of TIMP-1. LX-2, but not LX-1, proliferate in response to PDGF. Both lines express mRNAs for alpha1(I) procollagen and HSP47. Transforming growth factor beta1 stimulation increased their alpha1(I) procollagen mRNA expression, as determined by quantitative reverse transcription-polymerase chain reaction. LX-2, but not LX-1, cells are highly transfectable. Both lines had a retinoid phenotype typical of stellate cells. Microarray analyses showed strong similarity in gene expression between primary HSCs and either LX-1 (98.4%) or LX-2 (98.7%), with expression of multiple neuronal genes.

CONCLUSIONS

LX-1 and LX-2 human HSC lines provide valuable new tools in the study of liver disease. Both lines retain key features of HSCs. Two unique advantages of LX-2 are their viability in serum free media and high transfectability.

MUC1 (CD227) interacts with lck tyrosine kinase in Jurkat lymphoma cells and normal T cells

MUC1 (CD227) is a large transmembrane epithelial mucin glycoprotein, which is aberrantly overexpressed in most adenocarcinomas and is a target for immune therapy for epithelial tumors. Recently, MUC1 has been detected in a variety of hematopoietic cell malignancies including T and B cell lymphomas and myelomas; however, its function in these cells is not clearly defined. Using the Jurkat T cell lymphoma cell line and normal human T cells, we demonstrate that MUC1 is not only expressed in these cells but is also phosphorylated upon T cell receptor (TCR) ligation and associates with the Src-related T cell tyrosine kinase, p56lck. Upon TCR-mediated activation of Jurkat cells, MUC1 is found in the low-density membrane fractions, where linker of T cell activation is contained. Abrogation of MUC1 expression in Jurkat cells by MUC1-specific small interfering RNA resulted in defects in TCR-mediated downstream signaling events associated with T cell activation. These include reduction in Ca2+ influx and extracellular signal-regulated kinase 1/2 phosphorylation, leading to a decrease in CD69 expression, proliferation, and interleukin-2 production. These results suggest a regulatory role of MUC1 in modulating proximal signal transduction events through its interaction with proteins of the activation complex.

Comparative evaluation of antiproliferative activity and induction of apoptosis by some fluoroquinolones with a human non-small cell lung cancer cell line in culture

Lung cancer is the leading cause of cancer- related death in the world today. Since the effective management of drug resistant lung cancer, and particularly non-small cell lung carcinomas is a major problem, attempts need to be made to identify new potential anticancer drugs that can kill non-small cell lung cancer cells efficiently. In the present study, a human non-small cell lung carcinoma NCI-H460 cell line was used to evaluate the antiproliferative activity of Fluoroquinolones like Enoxacin, Norfloxacin, Ciprofloxacin and Levofloxacin. As determined by Sulphorodhamine B assay (SRB assay), all Fluoroquinolones caused cellular growth inhibition in a concentration and time-dependent manner. Enoxacin was found to be the most effective Fluoroquinolone followed by Norfloxacin, Ciprofloxacin and Levofloxacin. Growth inhibitory effects were also found to be independent of the concentrations of serum growth factors in culture medium or variation of initial cell seeding density and proved to be irreversible in nature. Appearance of rounded cells with altered morphology and cell surface blebbing indicated cell killing by apoptosis. Cell shrinkage, nuclear condensation & fragmentation, and cytoplasmic blebbing as indicated by MGG staining confirmed this to be the case. Thus, this investigation clearly demonstrated that the NCI-H460 human non-small cell lung carcinoma cell line is highly sensitive to Fluoroquinolone treatment. The Fluoroquinolones used in this study which are clinically used as antibacterial agents, can also inhibit tumor cell growth suggesting their potential use in a strategy for cancer treatment which might help in controlling cancer.

Protective effects of IL-1Ra or vIL-10 gene transfer on a murine model of wear debris-induced osteolysis

The current study evaluated the protective effects of anti-inflammatory cytokine gene transfer on osteolysis provoked by orthopedic biomaterial particles using a murine model of inflammatory bone loss. A section of bone was surgically implanted into an air pouch established on a syngeneic recipient mouse. Inflammation was provoked by introduction of ultra-high-molecular-weight polyethylene (UHMWPE) particles into the pouch, and retroviruses encoding for interleukin-1 receptor antagonist (hIL-1Ra), viral interleukin-10 (vIL-10), or LacZ genes were injected. Pouch fluid and tissue were harvested 7 days later for histological and molecular analyses. The results indicated that IL-1Ra or vIL-10 gene transfer significantly inhibited IL-1beta and tumor necrosis factor (TNF) expression at both mRNA and protein levels. There were significantly lower mRNA expressions of calcitonin receptor and cathepsin K in RNA isolated from hIL-1Ra- or vIL-10-transduced pouches than LacZ-transduced and virus-free controls. Both anti-inflammatory cytokine gene transfers significantly reduced the mRNA expression of M-CSF (70-90%) and RANK (>65%) in comparison with LacZ- and virus-free controls. Histological examination showed that hIL-1Ra or vIL-10 gene transfer dramatically abolished UHMWPE-induced inflammatory cellular infiltration and bone pit erosion compared to LacZ-transduced and virus-free controls. Histochemical staining revealed significantly fewer osteoclast-like cells in samples treated with IL-1Ra or vIL-10 gene transfer. In addition, bone collagen content was markedly preserved in the groups with anti-inflammatory cytokine gene transfers compared with the other two groups. Overall, retrovirus-mediated hIL-1Ra or vIL-10 gene transfer effectively protected against UHMWPE-particle-induced bone resorption, probably due to the inhibition of IL-1/TNF-induced M-CSF production and the consequent osteoclast recruitment and maturation.

Role of glucose and ketone bodies in the metabolic control of experimental brain cancer

Brain tumours lack metabolic versatility and are dependent largely on glucose for energy. This contrasts with normal brain tissue that can derive energy from both glucose and ketone bodies. We examined for the first time the potential efficacy of dietary therapies that reduce plasma glucose and elevate ketone bodies in the CT-2A syngeneic malignant mouse astrocytoma. C57BL/6J mice were fed either a standard diet unrestricted (SD-UR), a ketogenic diet unrestricted (KD-UR), the SD restricted to 40% (SD-R), or the KD restricted to 40% of the control standard diet (KD-R). Body weights, tumour weights, plasma glucose, beta-hydroxybutyrate (beta-OHB), and insulin-like growth factor 1 (IGF-1) were measured 13 days after tumour implantation. CT-2A growth was rapid in both the SD-UR and KD-UR groups, but was significantly reduced in both the SD-R and KD-R groups by about 80%. The results indicate that plasma glucose predicts CT-2A growth and that growth is dependent more on the amount than on the origin of dietary calories. Also, restriction of either diet significantly reduced the plasma levels of IGF-1, a biomarker for angiogenesis and tumour progression. Owing to a dependence on plasma glucose, IGF-1 was also predictive of CT-2A growth. Ketone bodies are proposed to reduce stromal inflammatory activities, while providing normal brain cells with a nonglycolytic high-energy substrate. Our results in a mouse astrocytoma suggest that malignant brain tumours are potentially manageable with dietary therapies that reduce glucose and elevate ketone bodies.

Immunocytochemical detection of p21ras, Raf-1, ERK1/MAP kinase and PKC isoforms in a 20-methylcholanthrene-induced transformed murine embryonal fibroblast cells in culture

An immunocytochemical study using antibodies against p21ras, Raf-1, MAP kinase/ERK1 and PKCalpha, beta, gamma, delta, epsilon, zeta, isoforms were performed on a 20-methylcholanthrene-induced transformed murine embryonal fibroblast cells in both in vitro and in vivo growth conditions. Altered expression of p21ras, Raf-1, MAP kinase in this particular cell line strongly supported the previous findings of the activation of one component of signal transduction under the influence of the other in the MAP kinase cascade of signal transduction during neoplastic transformation and which also seemed to be involved in CNCI-PM-20 cell line. The altered expression of PKCalpha, beta, and delta was thought to be an epigenetic event occurring under the indirect influence of other changes in these cells. Host physiology and metabolism did not have much impact on the expression of these gene products after biological incubation of these cells in syngenic host.

TNF receptor gene therapy results in suppression of IgG2a anticollagen antibody in collagen induced arthritis

BACKGROUND

Therapeutic strategies to block tumour necrosis factor alpha (TNFalpha) activity in experimental autoimmune arthritis models and rheumatoid arthritis (RA) have proved highly successful, and provide sustained beneficial effects.

OBJECTIVE

To examine whether TNFalpha inhibition has immunological activity beyond the reduction of inflammation in collagen induced arthritis (CIA), an established experimental model of RA.

METHODS

Arthritic DBA/1 mice received single periarticular injections of retroviral constructs encoding human TNF receptor (TNF-R) into the affected arthritic paw, at the onset of arthritis. Severity of arthritis, antibodies to collagen type II (CII), and extent of pathological joint damage of arthritic paws were compared between TNF-R and media treated (control) animals 3, 7, 14, 21, and 49 days after disease onset.

RESULTS

Severity of CIA was significantly decreased in TNF-R treated animals compared with controls, 14-34 days after disease onset. Joint destruction was reduced in TNF-R injected joints and in the uninjected contralateral and ipsilateral paws of TNF-R treated animals. Seven days after disease onset, TNF-R treated mice had lower levels of inflammatory Th1 driven IgG2a antibodies to CII (p<0.05) than controls. This altered the anticollagen IgG2a:IgG1 ratio towards Th2 driven IgG1.

CONCLUSIONS

Local TNF-R gene therapy in CIA appears to have systemic effects on the anti-CII antibodies. The overall influence of TNF-R gene therapy is that it inhibits the progression of CIA mainly by suppressing the inflammatory Th1 response rather than by stimulating a Th2 response. Therefore, periarticular TNF-R gene therapy may have excellent therapeutic potential in RA.

Diffusion tensor imaging of normal and injured developing human brain - a technical review

The application of diffusion tensor imaging (DTI) to the evaluation of developing brain remains an area of active investigation. This review focuses on the changes in DTI parameters which accompany both brain maturation and injury. The two primary pieces of information available from DTI studies-water apparent diffusion coefficient and diffusion anisotropy measures-change dramatically during development, reflecting underlying changes in tissue water content and cytoarchitecture. DTI parameters also change in response to brain injury. In this context, not only does DTI offer the possibility of detecting injury earlier than conventional imaging methods, but also appears more sensitive to disruption of white matter than any other imaging method. DTI offers unique insight into brain injury and maturation, and does so in a fashion that can be readily applied in a clinical setting.

Altered gene expression during nimesulide-mediated inhibition of apoptotic death in human chondrocytes

We previously found that the cyclooxygenase (COX)-2 preferential inhibitor nimesulide protects rodents' chondrocytes against apoptotic death in vitro. In the present study, we found that nimesulide also reduces staurosporine-mediated apoptotic death in human chondrocytes in vitro. Using cDNA microarrays, we explored alterations in gene expression during human chondrocytic apoptosis, and the influence of nimesulide therapy on these changes. Based on their known biologic activities, candidate gene products with altered expression were assigned to clusters of biological functions and mechanisms, and analysed for specific sets of alterations. We found that the expression of genes involved in cell proliferation is differentially regulated during staurosporine-mediated apoptotic death in human chondrocytes. Treatment with nimesulide reversed the staurosporine-mediated effects on these gene products during protection against apoptosis. The study suggests that nimesulide, in addition to its analgesic effect, may confer chondroprotection through mechanisms beyond classical COX inhibition.

Are accident and emergency consultants as accurate as consultant radiologists in interpreting plain skeletal radiographs taken at a minor injury unit?

The objective of this study was to compare the accuracy of an accident and emergency (A&E) consultant in interpreting plain skeletal radiographs with that of a consultant radiologist (CR). It took the form of a retrospective study of 2133 radiographs taken in a Minor Injury Unit (MIU). A&E consultant reports on these films were compared with those of a CR and also with a gold standard. The A&E consultant diagnoses achieved an accuracy of 98.5% (CR 97.8%), sensitivity of 97.8% (CR 98.1%), specificity of 98.8% (CR 97.7%), positive predictive value of 97.3% (CR 95.1%) and negative predictive value of 98.97% (CR 99.07%) (gold standard of 100%). In conclusion, the A&E consultant reports of plain skeletal radiographs generated from an MIU were as accurate as those of a consultant radiologist. This could have significant implications for the wet reporting of A&E departmental radiographs.

Dietary restriction reduces angiogenesis and growth in an orthotopic mouse brain tumour model

Diet and lifestyle produce major effects on tumour incidence, prevalence, and natural history. Moderate dietary restriction has long been recognised as a natural therapy that improves health, promotes longevity, and reduces both the incidence and growth of many tumour types. Dietary restriction differs from fasting or starvation by reducing total food and caloric intake without causing nutritional deficiencies. No prior studies have evaluated the responsiveness of malignant brain cancer to dietary restriction. We found that a moderate dietary restriction of 30-40% significantly inhibited the intracerebral growth of the CT-2A syngeneic malignant mouse astrocytoma by almost 80%. The total dietary intake for the ad libitum control group (n=9) and the dietary restriction experimental group (n=10) was about 20 and 13 Kcal x day(-1), respectively. Overall health and vitality was better in the dietary restriction-fed mice than in the ad libitum-fed mice. Tumour microvessel density (Factor VIII immunostaining) was two-fold less in the dietary restriction mice than in the ad libitum mice, whereas the tumour apoptotic index (TUNEL assay) was three-fold greater in the dietary restriction mice than in the ad libitum mice. CT-2A tumour cell-induced vascularity was also less in the dietary restriction mice than in the ad libitum mice in the in vivo Matrigel plug assay. These findings indicate that dietary restriction inhibited CT-2A growth by reducing angiogenesis and by enhancing apoptosis. Dietary restriction may shift the tumour microenvironment from a proangiogenic to an antiangiogenic state through multiple effects on the tumour cells and the tumour-associated host cells. Our data suggest that moderate dietary restriction may be an effective antiangiogenic therapy for recurrent malignant brain cancers.