Oxidative stress in acute pancreatitis: lost in translation?

Oxidative stress has been implicated in the pathogenesis of acute pancreatitis, a severe and debilitating inflammation of the pancreas that carries a significant mortality, and which imposes a considerable financial burden on the health system due to patient care. Although extensive efforts have been directed towards the elucidation of critical underlying mechanisms and the identification of novel therapeutic targets, the disease remains without a specific therapy. In experimental animal models of acute pancreatitis, increased oxidative stress and decreased antioxidant defences have been observed, changes also detected in patients clinically. However, despite the promise of studies evaluating the effects of antioxidants in these model systems, translation to the clinic has thus far been disappointing. This may reflect many factors involved in the design of both preclinical and clinical evaluations of antioxidant therapy, not least the fact that most experimental studies have focussed on pre-treatment rather than post-injury assessment. This review has examined evidence relating to the involvement of oxidative stress in the pathophysiology of acute pancreatitis, focussing on experimental models and the clinical experience, including the experimental techniques employed and potential of antioxidant therapy.

Water polarization induced by thermal gradients: the extended simple point charge model (SPC/E).

We investigate the non-equilibrium response of extended simple point charge (SPC/E) water to thermal gradients. Using non-equilibrium molecular dynamics simulations, we show that SPC/E water features the thermo-polarization orientation effect, namely, water becomes polarized as a response to a thermal gradient. The polarization field increases linearly with the thermal gradient, in agreement with predictions of non-equilibrium thermodynamics theory. This observation confirms the generality of the thermo-polarization effect, first reported using the Modified Central Force Model (MCFM), and shows this physical effect is present irrespective of the water model details, in particular, dipole moment magnitude and model flexibility. The magnitude of the effect is the same for both models, although the sign of the electrostatic field is reversed in going from the MCFM to the SPC/E model. We further analyze the impact that the molecular geometry and mass distribution has on the magnitude of the polarization. Our results indicate that the thermo-polarization effect should be observed in a wide range of polar fluids, including fluids where hydrogen bonding is not present. Using various molecular models, we show that the polarization of these fluids under appropriate thermodynamic conditions can be of the same order or stronger than in water.

Statistical mechanics of coarse graining: estimating dynamical speedups from excess entropies.

The excess entropy of fluids has been shown to play a decisive role in the determination of dynamical properties [Y. Rosenfeld, Phys. Rev. A 15, 2545 (1977)]. We argue that it could play an equally important role in connecting dynamical properties of atomistic and coarse-grained models of molecular fluid systems. Molecular dynamics simulations for an atomistic and a coarse-grained model of water confirm the validity of this conjecture, showing that the sizable enhancement of the diffusion rate upon coarse-graining is a simple function of the difference in the excess entropy of the two models. This empirical observation could ease the way to a first-principles prediction of the relation of dynamical properties estimated from models at different resolution.

Computational verification of two universal relations for simple ionic liquids. Kinetic properties of a model 2:1 molten salt.

Two semianalytical relations [Nature, 1996, 381, 137 and Phys. Rev. Lett. 2001, 87, 245901] predicting dynamical coefficients of simple liquids on the basis of structural properties have been tested by extensive molecular dynamics simulations for an idealized 2:1 model molten salt. In agreement with previous simulation studies, our results support the validity of the relation expressing the self-diffusion coefficient as a function of the radial distribution functions for all thermodynamic conditions such that the system is in the ionic (ie., fully dissociated) liquid state. Deviations are apparent for high-density samples in the amorphous state and in the low-density, low-temperature range, when ions condense into AB(2) molecules. A similar relation predicting the ionic conductivity is only partially validated by our data. The simulation results, covering 210 distinct thermodynamic states, represent an extended database to tune and validate semianalytical theories of dynamical properties and provide a baseline for the interpretation of properties of more complex systems such as the room-temperature ionic liquids.

Urinalysis in Western culture: a brief history.

Today physicians use urine to diagnose selective conditions but from ancient times until the Victorian era, urine was used as the primary diagnostic tool. Laboratory medicine began with the analysis of human urine, which was called uroscopy and today is termed urinalysis. Uroscopy was the mirror of medicine for thousands of years. From a liquid window through which physicians felt they could view the body's inner workings. Numerous, somewhat accurate, physiologic theories arose from uroscopy. Then the importance of urinary diagnosis became exaggerated, and increasingly complex, until physicians required only the presence of urine, not patients, to diagnose disease. Uroscopy then escaped medical control, becoming first a home health aid and then a tool of uneducated practitioners. Thomas Brian led a medical rebellion against all uses of uroscopy and published the Pisse Prophet, a book that devastated uroscopy.

New sodalite frameworks; synthetic tugtupite and a beryllosilicate framework with a 3:1 Si:Be ratio.

Compounds of the formula Na8[Si(6 +y)Be(y)Al(6 - 2y)O24]X2, with X = Cl and Br, and y = 1, 2 and 3 have been synthesised and structurally characterised by combined powder X-ray and neutron diffraction profile analysis. These materials adopt the sodalite framework (SOD) with the tetrahedral species, BeO4, AlO4 and SiO4, disordered across the framework positions. Na8[Si8Be2Al2O24]Cl2, (y = 2), is a synthetic analogue of the naturally occurring semi-precious gemstone tugtupite, while Na8[Si9Be3O24]X2, X = Cl and Br represents a new tetrahedral framework stoichiometry with a Si ratio Be ratio of 3 ratio 1. Additional characterisation using 29Si MASNMR, IR spectroscopy and high-temperature, neutron diffraction show that the observed structure-property trends found when modelling sodalite materials can be extended to these new framework compositions.

Evaluation of an extensive tuberculosis contact investigation in an urban community and jail.

SETTING: Urban community and jail. OBJECTIVES/DESIGN: Evaluate outcome and process of an extensive tuberculosis contact investigation, including completion of treatment of latent TB infection (TLTBI). RESULTS: Between April 2000 and September 2001, 18 epidemiologically-linked tuberculosis cases were identified; 15 were culture-confirmed, all with a matching 14-band DNA fingerprint pattern. The source case had cavitary pulmonary disease and had been incarcerated 4 months prior to diagnosis. Sixty-six of 67 (99%) community contacts and 221/344 (64%) jail contacts were evaluated. The presumed new infection rate was 56% for community contacts (11 cases, 25 tuberculin skin test [TST] positive) and 20% for jail contacts (6 cases, 32 TST converters). Screening results for 113 (33%) jail contacts were obtained in the jail TST registry upon rearrest. All identified cases completed treatment. Of 22 community contacts initiating TLTBI, 11 completed (44% of infected, 50% of initiators). Of 32 infected jail contacts, 12 initiated TLTBI (all who remained incarcerated), and 10 completed (31% of infected, 83% of initiators). None of 20 additional in-fected jail contacts, all of whose TST conversions were identified with re-arrest data, were subsequently located. Two additional related cases have been identified as of October 2003. CONCLUSIONS: Close health department/corrections collaboration facilitated this extensive contact investigation, which identified high Mycobacterium tuberculosis transmission rates and controlled the outbreak. Numerous contacts were identified and screened, but rates of treatment completion for infected contacts were low. Novel strategies are needed to maximize the number of infected contacts who are not only identified and evaluated, but completely treated.

The HMG-domain protein BAP111 is important for the function of the BRM chromatin-remodeling complex in vivo.

The Drosophila trithorax group gene brahma (brm) encodes the ATPase subunit of a SWI/SNF-like chromatin-remodeling complex. A key question about chromatin-remodeling complexes is how they interact with DNA, particularly in the large genomes of higher eukaryotes. Here, we report the characterization of BAP111, a BRM-associated protein that contains a high mobility group (HMG) domain predicted to bind distorted or bent DNA. The presence of an HMG domain in BAP111 suggests that it may modulate interactions between the BRM complex and chromatin. BAP111 is an abundant nuclear protein that is present in all cells throughout development. By using gel filtration chromatography and immunoprecipitation assays, we found that the majority of BAP111 protein in embryos is associated with the BRM complex. Furthermore, heterozygosity for BAP111 enhanced the phenotypes resulting from a partial loss of brm function. These data demonstrate that the BAP111 subunit is important for BRM complex function in vivo.

Mutations in Drosophila heat shock cognate 4 are enhancers of Polycomb.

The homeotic genes controlling segment identity in Drosophila are repressed by the Polycomb group of genes (PcG) and are activated by genes of the trithorax group (trxG). An F(1) screen for dominant enhancers of Polycomb yielded a point mutation in the heat shock cognate gene, hsc4, along with mutations corresponding to several known PcG loci. The new mutation is a more potent enhancer of Polycomb phenotypes than an apparent null allele of hsc4 is, although even the null allele occasionally displays homeotic phenotypes associated with the PcG. Previous biochemical results had suggested that HSC4 might interact with BRAHMA, a trxG member. Further analyses now show that there is no physical or genetic interaction between HSC4 and the Brahma complex. HSC4 might be needed for the proper folding of a component of the Polycomb repression complex, or it may be a functional member of that complex.

The ISWI chromatin-remodeling protein is required for gene expression and the maintenance of higher order chromatin structure in vivo.

Drosophila ISWI, a highly conserved member of the SWI2/SNF2 family of ATPases, is the catalytic subunit of three chromatin-remodeling complexes: NURF, CHRAC, and ACF. To clarify the biological functions of ISWI, we generated and characterized null and dominant-negative ISWI mutations. We found that ISWI mutations affect both cell viability and gene expression during Drosophila development. ISWI mutations also cause striking alterations in the structure of the male X chromosome. The ISWI protein does not colocalize with RNA Pol II on salivary gland polytene chromosomes, suggesting a possible role for ISWI in transcriptional repression. These findings reveal novel functions for the ISWI ATPase and underscore its importance in chromatin remodeling in vivo.

Emphysematous cholecystitis in a Siberian husky.

A 6-year-old, intact male Siberian husky was evaluated for a 24-hour history of vomiting and lethargy. Diagnosis of emphysematous cholecystitis was achieved based on survey abdominal radiographs, a barium contrast gastrointestinal series, and abdominal ultrasound. Diagnosis and medical and surgical management of the condition are discussed.

A SWI/SNF-related chromatin remodeling complex, E-RC1, is required for tissue-specific transcriptional regulation by EKLF in vitro.

Erythroid Krüppel-like factor (EKLF) is necessary for stage-specific expression of the human beta-globin gene. We show that EKLF requires a SWI/SNF-related chromatin remodeling complex, EKLF coactivator-remodeling complex 1 (E-RC1), to generate a DNase I hypersensitive, transcriptionally active beta-globin promoter on chromatin templates in vitro. E-RC1 contains BRG1, BAF170, BAF155, and INI1 (BAF47) homologs of yeast SWI/SNF subunits, as well as a subunit unique to higher eukaryotes, BAF57, which is critical for chromatin remodeling and transcription with EKLF. E-RC1 displays functional selectivity toward transcription factors, since it cannot activate expression of chromatin-assembled HIV-1 templates with the E box-binding protein TFE-3. Thus, a member of the SWI/SNF family acts directly in transcriptional activation and may regulate subsets of genes by selectively interacting with specific DNA-binding proteins.

Transcription of chromatin: these are complex times.

Transcription of chromatin-packaged genes involves highly regulated changes in nucleosomal structure that control DNA accessibility. Two systems that facilitate these changes are ATP-dependent chromatin remodeling complexes and enzymatic complexes which control histone acetylation and deacetylation. Recent studies provide insight on the role of these remodeling machines and specific transcription factors in the expression of viral, inducible, and tissue-restricted genes.

NF-E2 disrupts chromatin structure at human beta-globin locus control region hypersensitive site 2 in vitro.

The human beta-globin locus control region (LCR) is responsible for forming an active chromatin structure extending over the 100-kb locus, allowing expression of the beta-globin gene family. The LCR consists of four erythroid-cell-specific DNase I hypersensitive sites (HS1 to -4). DNase I hypersensitive sites are thought to represent nucleosome-free regions of DNA which are bound by trans-acting factors. Of the four hypersensitive sites only HS2 acts as a transcriptional enhancer. In this study, we examine the binding of an erythroid protein to its site within HS2 in chromatin in vitro. NF-E2 is a transcriptional activator consisting of two subunits, the hematopoietic cell-specific p45 and the ubiquitous DNA-binding subunit, p18. NF-E2 binds two tandem AP1-like sites in HS2 which form the core of its enhancer activity. In this study, we show that when bound to in vitro-reconstituted chromatin, NF-E2 forms a DNase I hypersensitive site at HS2 similar to the site observed in vivo. Moreover, NF-E2 binding in vitro results in a disruption of nucleosome structure which can be detected 200 bp away. Although NF-E2 can disrupt nucleosomes when added to preformed chromatin, the disruption is more pronounced when NF-E2 is added to DNA prior to chromatin assembly. Interestingly, the hematopoietic cell-specific subunit, p45, is necessary for binding to chromatin but not to naked DNA. Interaction of NF-E2 with its site in chromatin-reconstituted HS2 allows a second erythroid factor, GATA-1, to bind its nearby sites. Lastly, nucleosome disruption by NF-E2 is an ATP-dependent process, suggesting the involvement of energy-dependent nucleosome remodeling factors.

Human herpesvirus 6: infection and disease following autologous and allogeneic bone marrow transplantation.

Human herpesvirus 6 activity (HHV-6) was studied in 15 allogeneic and 11 autologous marrow transplantation patients. After transplantation, HHV-6 was isolated from the peripheral blood mononuclear cells of 12 of 26 patients (6 allogeneic and 6 autologous). All isolates were variant B. Eleven of 26 and 12 of 19 patients showed salivary shedding of HHV-6 DNA before and after transplantation, respectively. The antibody titer increased in 7 of 26 patients. Thus, 23 of 26 patients showed evidence of active HHV-6 infection either by virus isolation, salivary shedding, or increases in antibody titers. The fraction of saliva specimens positive in 19 patients was negatively associated with their antibody titers (P= .005). The proportion of cultures positive increased after transplantation (P = .007). Sinusitis was associated with HHV-6 isolation in autologous recipients (P= .002). In allogeneic patients, active human cytomegalovirus infection was associated with HHV-6 isolation (P = .04). No association was observed between HHV-6 infection and GVHD, pneumonia, delay in engraftment, or marrow suppression. Of the 120 clinical events analyzed in 26 patients, HHV-6 was defined as a probable cause of 16 events in 9 patients based on the propinquity of HHV-6 activity and the clinical event plus the absence of other identified causes of the event.

Calixarenes with host-mediated potency in experimental tuberculosis: further evidence that macrophage lipids are involved in their mechanism of action.

Some time ago, it was found that attachment of hydrophilic polyoxyethylene chains to various hydrophobic phenols and alcohols gave water-soluble products which, although inactive in vitro, influenced and experimental tuberculous infection. With short chains the infection was suppressed, and with long chains it was promoted. Later work concentrated on Macrocyclon (short chain) and HOC-60 (long chain), both derived from a hydrophobic, polyphenolic calixarene. Growth of Mycobacterium tuberculosis inside macrophages (M phi) was inhibited by Macrocyclon and stimulated by HOC-60. Also, triglyceride lipase from M phi extracts and an extracellular phospholipase were inhibited by Macrocyclon and stimulated by HOC-60. This suggestion of a mechanism has been strengthened by the finding that M phi cultivated in monolayers and treated with Macrocyclon showed accumulation of lipid and little formation of fatty acid after incubation of killed cells. With HOC-60, lipid was depleted and much fatty acid was found.

Amobarbital evaluation of neurobehavioral function prior to therapeutic occlusion of brain arteriovenous malformations: a new neuropsychological procedure.

Because untreated arteriovenous malformations (AVMs) frequently result in some form of permanent neurological complication, treatment of AVMs is aggressively pursued A relatively new treatment consists of sending micropellets into blood vessels supplying the AVM core to block blood flow and "shrink" the AVM When vessels supplying the AVM are thought to also irrigate vital portions of brain, evaluations of neurobehavioral function after injection of amobarbital into intracranial vessels (Wada testing) may be performed to prevent significant complications folIowing embolization This study details our preliminary experience with Wada testing and electroencephalography (EEG) prior to AVM embolization in seven patients Neurobehavioral functions were continuously monitored after injection of 50-75 mg of amobarbital into target cerebral vessels No change in sensorimotor, cognitive, or EEG functions were detected in any of the superselective Wada examinations Embolization was performed following all negative Wada evaluations The only irreversible complication after embolization was a superior quadrantanopia No other permanent neurobehavioral sequelae resulted from embolization These preliminary findings suggest that simultaneous Wada/EEG monitoring may be useful in predicting neurobehavioral complications prior to AVM embolization.

Application of total organic carbon analysis to cleaning validation.

Cleaning validation is the process of assuring that cleaning procedures effectively remove residue from manufacturing equipment/facilities below a predetermined level. This is necessary to assure the quality of future products using the equipment, to prevent cross-contamination and as a GMP requirement. Currently, cleaning validation samples are measured using HPLC or spectrophotometric methods of analysis which are often time consuming and subject to a number of interferences. Total Organic Carbon (TOC) analysis is a new method which has previously only been applied to measurement of carbon residues on production surfaces for biopharmaceuticals. We have applied the TOC analysis method to a number of traditional pharmaceutical products including antibiotics, steroids, and antinauseants in addition to biopharmaceuticals. The method offers extremely low detection capability (ppm and ppb), rapid sample analysis time and therefore quick turn-around of production equipment and facilities. TOC analysis is also applicable to on-line analysis. The method allows the measurement of extraneous materials such as process intermediates, cleaning agents, and protein materials not possible by other methods.

WEHI-13VAR: a stable and sensitive variant of WEHI 164 clone 13 fibrosarcoma for tumor necrosis factor bioassay.

Bioassaying tumor necrosis factor (TNF) relies not only on a sensitive but also on a stable cell line towards TNF action. A variant of WEHI 164 clone 13, WEHI-13VAR, was characterized by us. This variant demonstrated both stability and high sensitivity towards rTNF-alpha or rTNF-beta when assayed in the presence of actinomycin-D (AcD). Fifteen subclones were generated from WEHI-13VAR (rTNF-alpha; ED50 range: 0.005-0.065 ng/ml). No clones were found more sensitive than the AcD-treated WEHI-13VAR cell line. An important feature of this line is its stable sensitivity. The stability of the cell line sensitivity towards rTNF-beta was demonstrated in the presence of AcD over a period of 16 months with an average ED50 of 0.046 +/- 0.004 ng/ml. In conclusion, unlike other TNF-sensitive cell lines in which the sensitivity is lost or the stability is unknown, WEHI-13VAR provides a sensitive, reliable and stable bioassay system to detect cytotoxin, TNF-alpha, and TNF-beta.