Treatment of inflammatory arthritis via targeting of tristetraprolin, a master regulator of pro-inflammatory gene expression.

OBJECTIVES: Tristetraprolin (TTP), a negative regulator of many pro-inflammatory genes, is strongly expressed in rheumatoid synovial cells. The mitogen-activated protein kinase (MAPK) p38 pathway mediates the inactivation of TTP via phosphorylation of two serine residues. We wished to test the hypothesis that these phosphorylations contribute to the development of inflammatory arthritis, and that, conversely, joint inflammation may be inhibited by promoting the dephosphorylation and activation of TTP. METHODS: The expression of TTP and its relationship with MAPK p38 activity were examined in non-inflamed and rheumatoid arthritis (RA) synovial tissue. Experimental arthritis was induced in a genetically modified mouse strain, in which endogenous TTP cannot be phosphorylated and inactivated. In vitro and in vivo experiments were performed to test anti-inflammatory effects of compounds that activate the protein phosphatase 2A (PP2A) and promote dephosphorylation of TTP. RESULTS: TTP expression was significantly higher in RA than non-inflamed synovium, detected in macrophages, vascular endothelial cells and some fibroblasts and co-localised with MAPK p38 activation. Substitution of TTP phosphorylation sites conferred dramatic protection against inflammatory arthritis in mice. Two distinct PP2A agonists also reduced inflammation and prevented bone erosion. In vitro anti-inflammatory effects of PP2A agonism were mediated by TTP activation. CONCLUSIONS: The phosphorylation state of TTP is a critical determinant of inflammatory responses, and a tractable target for novel anti-inflammatory treatments.

A new form of myeloma "kidney": shortened hemofilter survival and implications for membrane filtration plasmapheresis.

BACKGROUND: Despite rigorous focus on extracorporeal CRRT parameters such as access, blood flow, hemoconcentration, and anticoagulation, some patients have unexpected repetitive hemofilter clotting. We instead explored patient or disease-related factors that could be responsible, and present a case of plasma cell dyscrasia in which paraproteins caused hollow fiber failure. METHODS: A patient with IgG kappa chain multiple myeloma complicated by sepsis and acute renal failure was started on CVVH with a regional citrate anticoagulation protocol that typically yields filter life of >50 h. Polysulfone hemofilters repetitively clotted every 2-4 h, even after excluding circuit-related problems. Failed filters were examined by light, electron (EM), and immunofluorescence (IF) microscopy. RESULTS: Imaging of the hemofilters revealed several ultrastructural features typical for myeloma-associated alterations in native human tissue. Red cell rouleaux formation occurred within the hollow fibers. There was extensive protein layering on the luminal surface of the fibers with some extension into their walls: these deposits were IF+ for IgG kappa, and had a fibrillary substructure on EM. CONCLUSION: Extracorporeal hollow fiber phenomena recapitulate many intra-corporeal paraprotein effects such as those described in the kidney with plasma cell dyscrasias. Rapid protein layering suggests fouling of the membrane, decreased solute clearance before total device failure, and raises the theoretical concern that this might also occur during filtration plasmapheresis: we thus suggest serial serum free light chain levels to confirm their removal when using that technique. These findings emphasize the importance of disease rather than circuit-related factors that are under-appreciated causes of premature hemofilter failure.

Serial depletion and regeneration of the murine hematopoietic system. Implications for hematopoietic organization and the study of cellular aging.

The mouse hematopoietic system was subjected to repeated depletion and regeneration either by serial transfer of bone marrow cells through lethally irradiated recipients or by repeated treatment with the cycle-active drug hydroxyurea (HU). The capacity of surviving stem cells to proliferate and self-renew was assayed at intervals by two methods: (a) the spleen colony method; and (b) competitive repopulation of irradiated recipients using chromosome markers, with normal bone marrow cells as an internal control. The progressive decline in stem cell function that occurred during serial transfer of bone marrow and that had already begun after a single transfer was not seen during HU treatment; up to 25 pairs of HU injections given over more than 1 yr had no discernible effect on the number of stem cells present 3 wk after the final injection or on their capacity to self-renew. Within 2 d after exposure to HU, the average self-renewal capacity of surviving stem cells was enhanced. This implies that the drug selectively eliminates poorly self-renewing stem cells and hence that these enter cycle more readily than stem cells with a high self-replicative potential. However, the fact of being in cycle at the time of injection did not of itself affect self-renewal. The results show that serial transfer of bone marrow is not a valid method for studying clonal aging phenomena because it does not fulfill the assumptions on which such studies are based. No evidence was obtained for any intrinsic limitation in the capacity of bone marrow populations for repeated regeneration after HU-induced depletion. However, this does not necessarily imply that individual hematopoietic clones are capable of indefinite expansion because hematopoiesis may (as suggested by the relative resistance of highly self-replicative stem cells to mitogenic signals) proceed on the basis of clonal succession.

Intra-abdominal hypertension can be monitored with femoral vein catheters during CRRT and may cause access recirculation.

OBJECTIVES: Intra-abdominal hypertension (IAH) is an increasingly recognized disorder, and its diagnosis depends on accurate pressure monitoring. Bladder-based protocols are favored, but are not always clinically feasible. Abdominal venous (i.e. vena cava) pressure measurements are an alternative but are logistically challenging. We hypothesized that for patients suffering acute kidney injury, transducers built into renal replacement therapy (RRT) machines offer a simple opportunity to monitor pressures using catheters inserted via femoral veins. DESIGN: We performed in vitro testing of the accuracy of pressure transducers incorporated into continuous RRT devices, using highly calibrated instrumentation in the IAH-relevant range of 0 to +50 mmHg. We developed a protocol for using this modality in vivo, by stopping all pumps so as to allow equilibration of pressures: clinical application in a patient with femoral vein catheters and IAH was then described. RESULTS: In vitro analyses showed accuracy of the extracorporeal pressure transducers with an r² of 0.998, p < 0.001. In the patient case, the pressure transduced at the RRT device was identical to those obtained from bladder catheters. IAH also led to access recirculation and ineffective therapy. CONCLUSIONS: Pressure sensors incorporated into continuous RRT machines can be accurate in the IAH physiologic range, and thus may be used to easily measure intra-abdominal pressure via appropriate-length femoral vein-inserted access catheters. If not relieved, IAH can be an under-appreciated cause of access recirculation and ineffective clearance for any RRT modality (continuous or intermittent) using femoral catheters.

Self-assembly of artificial nucleobase 1H-benzimidazole-4,7-dione at the liquid/solid interface.

Self-assembly at the liquid/solid interface of an electrochemically active DNA nucleobase analogue, 1H-benzoimidazole-4,7-dione (Q), has been studied by means of scanning tunneling microscopy (STM). High-resolution STM images revealed the formation of well-ordered two-dimensional (2D) supramolecular nanostructures when the Q molecules are adsorbed onto the graphite surface from a 1-octanol solution. Detailed analysis shows that the observed 2D nanostructures are mainly dominated by hydrogen-bonded Q molecules. Since Q can be considered as a molecule mimicking the nucleobase guanine (G), which is known to form Watson-Crick base pairs with its complementary nucleobase cytosine (C), we have examined the binding ability of Q with C realized by available hydrogen-bonding sites on both Q and C molecules. Upon deposition of a mixture of Q and C molecules onto a graphite surface, one might expect that hydrogen-bonded QC dimers were observed in a new 2D self-assembled structure governed by inter- and intramolecular hydrogen-bonding interactions between Q and C molecules. However, our STM experiments showed that no well-ordered structures are formed and instead phase separation occurs where large-scale homodomains are formed consisting of the individual QQ and CC dimers. To gain further insight into the possible molecular arrangements of the Q and C nucleobases in the mixture phase, the high-resolution STM images are compared with the results from ab initio density functional theory (DFT) calculations.

Bilateral renal-cell carcinoma associated with an acquired VHL mutation and long-term trichloroethylene exposure.

BACKGROUND/AIMS: The genetic basis for clear-cell renal carcinomas has been established in familial and many sporadic forms. Whether the latter can be induced by environmental carcinogens remains controversial, with concern over solvents such as trichloroethylene (TCE). To study this putative relationship, we analyzed the VHL gene from a patient with long-term TCE exposure. METHODS: PCR amplification and sequencing of VHL exons 1 - 3 were performed on peripheral blood and tumor tissue. RESULTS: The tumor alone had a previously undescribed mutation in exon 1 of the VHL gene: deletion of a cytidine residue at position 291 relative to the first ATG start codon of the wild-type sequence. This deletion causes a frameshift and predicts an altered protein sequence from position 98 onwards. CONCLUSION: The affected amino acids are in the functionally important beta-domain of the VHL protein that is implicated in substrate binding for ubiquitylation, and we hypothesize the mutation lowers that affinity. There is loss of suppressor function when substrates such as hypoxia-inducible factor have impaired degradation: they accumulate and ultimately cause uncontrolled cell turnover. This association of a proposed occupational cause and occurrence of renal-cell carcinoma emphasizes the availability and use of VHL sequencing for both studying the pathophysiology of malignant transformation and potentially playing a clinical role in genetic counseling or risk assessment.

Lanthanum carbonate vs. sevelamer hydrochloride for the reduction of serum phosphorus in hemodialysis patients: a crossover study.

AIMS: The aim of this crossover study was to compare the reduction of serum phosphorus (SP) with fixed doses of the non-calcium-containing phosphate binders lanthanum carbonate (LC) and sevelamer hydrochloride (SH) in hemodialysis patients. METHODS: Following washout (2 - 3 weeks), 182 patients with SP >or= 6.0 mg/dl and calcium >or= 8.4 mg/dl were randomized (1:1) to receive LC (2,250 to 3,000 mg/day) or SH (4,800 to 6,400 mg/day) for 4 weeks. Patients underwent a second washout (2 weeks) and switched to the alternative binder for 4 weeks. RESULTS: At the end of treatment, LC had reduced SP by 1.7 +/- 0.1 mg/dl, compared with 1.4 +/- 0.1 mg/dl for SH; the difference was not statistically significant in the primary analysis (LOCF, p = 0.133). However, the reduction with LC was significantly greater than with SH in a prespecified key secondary analysis of patients who completed 4 weeks of treatment with each binder (0.5 mg/dl difference, p = 0.007). The reduction of SP was also greater with LC than SH after 1 week of treatment (p = 0.024). CONCLUSIONS: Although the primary analysis found no difference between LC and SH in the reduction of SP, a significant difference in favor of LC was observed in patients who completed treatment. The results of this study show interesting trends with respect to onset and duration of action that warrant further investigation in longer-term studies.

Adenine monolayers on the Au(111) surface: structure identification by scanning tunneling microscopy experiment and ab initio calculations.

From an interplay between scanning tunneling microscopy (STM) and ab initio density functional theory (DFT) we have identified and characterized two different self-assembled adenine (A) structures formed on the Au(111) surface. The STM observations reveal that both structures have a hexagonal geometry in which each molecule forms double hydrogen bonds with three nearest neighbors. One of the A structures, with four molecules in the primitive cell, has p2gg space group symmetry, while the other one, with two molecules in the cell, has p2 symmetry. The first structure is observed more frequently and is found to be the dominating structure after annealing. Experimental as well as theoretical findings indicate that the interaction of A molecules with the gold surface is rather weak and smooth across the surface. This enabled us to unequivocally characterize the observed structures, systematically predict all structural possibilities, based on all known A-A dimers, and provisionally optimize positions of the A molecules in the cell prior to full-scale DFT calculations. The theoretical method is a considerable improvement compared to the approach suggested previously by Kelly and Kantorovich [Surf. Sci. 589, 139 (2005)]. We propose that the less ordered p2gg symmetry structure is observed more frequently due to kinetic effects during island formation upon deposition at room temperature.

Two-dimensional supramolecular nanopatterns formed by the coadsorption of guanine and uracil at the liquid/solid interface.

A novel supramolecular nanostructure formed by the coadsorption of the complementary nucleobases guanine (G) and uracil (U) at the liquid (1-octanol solvent)/solid (graphite) interface is revealed by scanning tunneling microscopy (STM). The GU supramolecular structure is distinctly different from the structures observed by STM when the individual nucleobases (NB) are adsorbed on graphite in the control experiments. Using a systematic methodology and ab initio density functional theory (DFT), an atomistic structural model is proposed for the supramolecular coadsorbed GU structure, which consists of a periodic repetition of cyclic units based on the strongest GU base pairing.

An investigation into the interactions between self-assembled adenine molecules and a Au(111) surface.

Two molecular phases of the DNA base adenine (A) on a Au(111) surface are observed by using STM under ultrahigh-vacuum conditions. One of these phases is reported for the first time. A systematic approach that considers all possible gas-phase two-dimensional arrangements of A molecules connected by double hydrogen bonds with each other and subsequent ab initio DFT calculations are used to characterize and identify the two phases. The influence of the gold surface on the structure of A assemblies is also discussed. DFT is found to predict a smooth corrugation potential of the gold surface that will enable A molecules to move freely across the surface at room temperature. This conclusion remains unchanged if van der Waals interaction between A and gold is also approximately taken into account. DFT calculations of the A pairs on the Au(111) surface show its negligible effect on the hydrogen bonding between the molecules. These results justify the gas-phase analysis of possible assemblies on flat metal surfaces. Nevertheless, the fact that it is not the most stable gas-phase monolayer that is actually observed on the gold surface indicates that the surface still plays a subtle role, which needs to be properly addressed.

Understanding the disorder of the DNA base cytosine on the Au(111) surface.

Using ultrahigh vacuum scanning tunneling microscopy (STM) and ab initio density functional theory, we have investigated in detail structures formed by cytosine on the Au(111) surface in clean ultrahigh vacuum conditions. In spite of the fact that the ground state of this DNA base on the surface is shown to be an ordered arrangement of cytosine one-dimensional branches (filaments), this structure has never been observed in our STM experiments. Instead, disordered structures are observed, which can be explained by only a few elementary structural motifs: filaments, five- and sixfold rings, which randomly interconnect with each other forming bent chains, T junctions, and nanocages. The latter may have trapped smaller structures inside. The formation of such an unusual assembly is explained by simple kinetic arguments as a liquid-glass transition.

Coexistence of homochiral and heterochiral adenine domains at the liquid/solid interface.

In this work, the self-assembly of the DNA base molecule adenine (A) is imaged with high-resolution scanning tunneling microscopy (STM) at the liquid (1-octanol)/solid (HOPG) interface at room temperature. Rather surprisingly, the STM results reveal, for the first time, the spontaneous formation of two coexisting distinct (homo- and heterochiral) domains of adenine, which are formed at the liquid/solid interface without changing any experimental conditions. Ab initio density functional theory (DFT) calculations support our STM findings and suggest the existence of various A networks of nearly similar stability that all are constructed from the most stable A dimer.

Prevalence and mortality rate of congestive heart failure in the United States.

OBJECTIVES: The study was designed to determine the prevalence and mortality rate of congestive heart failure in noninstitutionalized men and women in the U.S. BACKGROUND: Congestive heart failure is a serious condition with significant morbidity and mortality. Earlier epidemiologic descriptions of congestive heart failure were constructed from small surveys, limited data, hospital records or death certificates. No nationally representative data from noninstitutionalized persons have been examined. METHODS: Data collected from the National Health and Nutrition Examination Survey (NHANES-I, 1971 to 1975) were used to determine the prevalence of heart failure on the basis of both self-reporting and a clinical definition. Mortality data were derived from the NHANES-I Epidemiologic Follow-up Study (1982 to 1986). RESULTS: The prevalence of self-reported congestive heart failure approximates 1.1% of the noninstitutionalized U.S. adult population; the prevalence of congestive heart failure based on clinical criteria is 2%. These estimates suggest that between 1 and 2 million adults are affected. Mortality at 10 and 15 years for those persons with congestive heart failure increases in graded fashion with advancing age, with men more likely to die than women. In the group greater than or equal to 55 years old, the 15-year total mortality rate was 39.1% for women and 71.8% for men. CONCLUSIONS: Congestive heart failure is a common problem in the U.S., with significant prevalence and mortality, both of which increase with advancing age. As the population of the U.S. becomes older, the health care impact of congestive heart failure will probably grow.

Prostate-specific antigen levels in nipple aspirate fluid correlate with breast cancer risk.

Despite the fact that breast cancer is the most common non-cutaneous cancer and a leading cause of cancer deaths in women, accepted markers of breast cancer risk miss up to 40% of these tumors. Moreover, screening methods involving the analysis of tissue or cells are limited by the need for a surgical biopsy. Nipple aspiration is a quick, efficient, noninvasive method to obtain breast epithelial cells, the cells at risk for transformation to carcinoma. Prostate-specific antigen (PSA), a protein thought to be specific to the prostate but recently found in a subset of breast tumors, has been correlated with improved survival. The purpose of this study was to measure PSA in a group of women with increasing breast cancer risk (no risk or family history of breast cancer, precancerous mastopathy, and invasive cancer) and determine if PSA correlates with risk. Nipple aspirate fluid was obtained from the intact breast and from surgical specimens using a modified breast pump. PSA was then measured in the fluid using a highly sensitive and specific immunofluorometric procedure. PSA was found at levels ranging from 0-13,423 ng/g of total protein, and there was a significant relationship between PSA level and breast cancer risk (P = 0.001). That is, all women with no risk factors and 90% of those with a family history had high PSA levels, whereas 68% of subjects with precancerous mastopathy or invasive cancer had low PSA levels. PSA was higher in premenopausal subjects (P = 0.002). After adjusting for the effect of menopausal status, there remained a significant association between PSA and breast cancer risk. These findings suggest that PSA in nipple aspirate fluid may be a useful marker of breast cancer risk.

Polymorphisms within the atrial natriuretic peptide gene in essential hypertension.

OBJECTIVE: To investigate polymorphisms in the atrial natriuretic peptide gene of African Americans at intron two (Hpall) and exon three (Scal). RESULTS: The allele frequency of the Hpall mutation was 25% in the hypertensive group (n =60) compared with only 3.4% in normotensive individuals (n = 44, P < 0.0001). The genotype heterozygote for the present mutation was much more common among those with hypertension (50 versus 6.8%, P < 0.0001). The groups were no different for the Scal site alone, although the two mutations were present together more often in the hypertensive group. The Hpall mutation was associated with hypertension in this typically salt-sensitive population.

Improved nutrition after the detection and treatment of occult gastroparesis in nondiabetic dialysis patients.

Malnutrition in dialysis patients is of multifactorial etiology and is associated with greatly increased morbidity and mortality. A low serum albumin level is one of the most powerful predictors of death and may persist despite optimization of the dialysis prescription. We retrospectively reviewed our experience in improving nutrition in nondiabetic patients with unexplained hypoalbuminemia. Using radionuclide solid-phase gastric emptying scans, we identified 6 patients who had occult gastroparesis. These patients (one on hemodialysis and five on peritoneal dialysis) were then treated with prokinetic medications (erythromycin elixir or metoclopramide) selected on the basis of their effectiveness in improving the scanning results after being given intravenously. Gastric emptying half-times improved from a median of 122 minutes (range, 95 to >300 minutes; normal, < or = 90 minutes) to 12 +/- 2 minutes (mean +/- SEM). The serum albumin increased from 3.3 +/- 0.04 g/dL to 3.7 +/- 0.08 g/dL at 3 months, with every patient's value higher than 3.5 g/dL. This improvement was statistically significant (P = 0.008) over the 5-month period of observation, which encompassed the 2 months before and 3 months after treatment. There was a linear improvement (P = 0.008) that showed a quadratic trend (P = 0.078) for a plateau at the final sampling point. The serum blood urea nitrogen, creatinine, and hematocrit levels remained unchanged (P > 0.1). We conclude that gastric emptying scans are valuable in identifying occult gastroparesis in high-risk patients and can guide the selection of prokinetic therapy, which may significantly increase serum albumin levels.

Quality of well-being before and after antibiotic treatment of pulmonary exacerbation in patients with cystic fibrosis.

General quality of life has only recently been measured with an objective tool in patients with cystic fibrosis (CF), and there have been no reported attempts to document changes in patients' overall well-being over time, as patients deteriorate or respond to intervention. We applied the Quality of Well-Being scale (QWB) in 28 patients with CF before and after a two-week course of oral ciprofloxacin used to treat pulmonary exacerbations. There were significant correlations between changes in QWB and various pulmonary function test results; QWB vs FEV1: r = 0.4, p less than 0.03; QWB vs FVC: r = 0.5, p less than 0.01; and QWB vs SaO2: r = 0.4, p less than 0.05. Thus, the QWB can track changes in general well-being in CF patients over a brief time and detect changes associated with pulmonary exacerbation and its treatment.

The quality of well-being in cystic fibrosis.

Traditional outcome measures in CF include PFTs, exercise tests, and several scoring systems that depend on pulmonary status and are largely subjective. The Quality of Well-being scale (QWB) is a widely used tool for measuring quality of life by three subscales: mobility, physical activity, and social activity, with points assigned within each subscale. The QWB has been shown to be valid in patients with COPD. We administered the QWB scale to 44 patients with CF, aged 7 to 36 years, and examined the relationship between QWB and PFTs, and in 15 patients the QWB vs exercise performance (peak VO2) on a progressive cycle ergometer test. QWB was significantly correlated with each variable examined: QWB vs FEV1, r = 0.5518 (p less than .0001); QWB vs FEF25-75%, r = 0.4793 (p less than .001); QWB vs PEFR, r = 0.4018 (p less than .01); QWB vs peak VO2, r = 0.5778 (p less than .01). The QWB scale is an objective measure that is significantly correlated with measures of performance and pulmonary function in CF. The relationship is not one of identity; further, the QWB is broad based and takes into account general well-being, not just pulmonary health, adding an important dimension to the care of patients with CF.