The prevalence of chronic kidney disease in rheumatology outpatients.

BACKGROUND: The introduction of routine reporting of estimated glomerular filtration rate coupled with a new definition of chronic kidney disease (CKD) has led to an unprecedented focus on kidney disease in many patient groups. In light of this, we performed an audit of patients attending the rheumatology clinics to assess the prevalence of CKD in this population. METHODS: Over a four week period, we reviewed the renal function of all patients attending the rheumatology clinics and day ward at our hospital (n=351). Renal function was assessed using the 4-variable MDRD formula. We then interviewed those patients with estimated glomerular filtration rate (eGFR) of 59 ml/min or lower. RESULTS: We found a prevalence rate of 18% for stage 3 CKD or lower in our audit population. Surprisingly, 60.3% of patients in this category were not aware of any problems with their kidneys (n=38). CONCLUSIONS: The prevalence rate of 18% for stage 3 CKD or lower is significantly higher than the five per cent reported within the general population. As a result of this audit, we now plan to ensure that these patients undergo measurement of blood pressure, eGFR, and urinalysis on a six to twelve monthly basis.

Past environmental sun exposure and risk of multiple sclerosis: a role for the Cdx-2 Vitamin D receptor variant in this interaction.

Multiple studies have provided evidence for an association between reduced sun exposure and increased risk of multiple sclerosis (MS), an association likely to be mediated, at least in part, by the vitamin D hormonal pathway. Herein, we examine whether the vitamin D receptor (VDR), an integral component of this pathway, influences MS risk in a population-based sample where winter sun exposure in early childhood has been found to be an important determinant of MS risk. Three polymorphisms within the VDR gene were genotyped in 136 MS cases and 235 controls, and associations with MS and past sun exposure were examined by logistic regression. No significant univariate associations between the polymorphisms, rs11574010 (Cdx-2A > G), rs10735810 (Fok1T > C), or rs731236 (Taq1C > T) and MS risk were observed. However, a significant interaction was observed between winter sun exposure during childhood, genotype at rs11574010, and MS risk (P = 0.012), with the 'G' allele conferring an increased risk of MS in the low sun exposure group (

Melanocortin 1 receptor genotype, past environmental sun exposure, and risk of multiple sclerosis.

OBJECTIVE: Low past sun exposure, fair skin type, and polymorphisms of the MC1R gene have been associated with multiple sclerosis (MS) risk. We aimed to investigate the interplay between melanocortin 1 receptor gene variants, red hair/fair skin phenotype, and past environmental sun exposure in MS. METHODS: Population-based case-control study in Tasmania, Australia, involving 136 cases with MS and 272 controls randomly drawn from the community and matched on sex and year of birth. Measures included past sun exposure by calendar and questionnaire, spectrophotometric skin type, and MC1R genotype, with any MC1R Arg151Cys, Arg160Trp, or Asp294His alleles present denoted as red hair color (RHC) variant. RESULTS: The association between RHC variant genotype and MS was more evident for women (odds ratio 2.02 [1.15-3.54]) than for men (odds ratio 0.65 [0.27-1.57]) (difference in effect, p = 0.03). The RHC variant genotype was associated with behavioral sun avoidance. In addition, increasing summer sun exposure at ages 6 through 10 years was associated with reduced MS risk among those with no RHC variant (p = 0.03), but not among those with RHC variant genotype (p = 0.15; difference in effect, p = 0.02). Similar findings were evident for other past sun exposure measures and when the sample was restricted to women only. CONCLUSION: The interplay between red hair color variant genotype, red hair/fair skin phenotype, and multiple sclerosis (MS) is complex. The modification of past sun exposure by MC1R genotype provides further support that ultraviolet radiation or derivatives such as vitamin D may be causally related to a reduced MS risk.

Leishmaniasis host response loci (lmr1-3) modify disease severity through a Th1/Th2-independent pathway.

The severity of disease caused by infection with Leishmania major depends critically on the genetics of the host. Early induction of T helper (Th)1-type immune responses in the resistant C57BL/6 mice and Th2-type responses in the susceptible BALB/c mice are thought to determine cure or disease, respectively. We have previously mapped three host response loci in a genetic cross between C57BL/6 and BALB/c mice, and here we show definitively the involvement of these loci in disease severity using animals congenic for each of the loci. Surprisingly, in the late stage of infection when the difference in disease severity between congenic and parental mice was most pronounced, their cytokine profile correlated with the genetic background of the mice and not with the severity of disease. This indicates that the loci that we have mapped are acting by a mechanism independent of Th phenotype.

Functional analysis and treatment of self-injury associated with transitions.

We applied functional analysis methodology to the assessment and treatment of 2 individuals' self-injurious behavior (SIB), which was reported to be occasioned by transitions from one activity or location to another. A structural (task) analysis of activity transitions identified at least three separate components that might influence behavior either alone or in combination: (a) termination of a prechange activity, (b) initiation of a postchange activity, and (c) movement from one location to another. Results of preference and avoidance assessments were used to identify activities to which participants were exposed in varying arrangements during transitions in a functional analysis. Results of 1 participant's functional analysis indicated that his SIB was maintained by avoidance of having to change locations, regardless of the activity terminated prior to the change or the activity initiated following it. The 2nd participant's analysis revealed the same function but also an additional one: avoidance of certain task initiations. This information was used to identify transition contexts during intervention and to design treatment procedures appropriate for a given context and behavioral function. A procedure involving advance notice of an upcoming transition had no effect on SIB, and differential reinforcement of alternative behavior (DRA) had limited effects in the absence of extinction. Sustained decreases in SIB were observed when DRA was combined with extinction and response blocking. Further extensions of functional analysis methodology to the assessment of problem behavior in situations characterized by multiple or protracted stimulus changes are discussed.

A unique sialidase that cleaves the Neu5Gcalpha2-->5-O(glycolyl)Neu5Gc linkage: comparison of its specificity with that of three microbial sialidases toward four sialic acid dimers.

We found that the hepatopancreas of oyster, Crassostrea virginica, contained a sialidase capable of releasing Neu5Gc from the novel polysialic acid chain (-->5-O(glycolyl)Neu5Gcalpha2-->)n more efficiently than from the conventional type of polysialic acid chains, (-->8Neu5Acalpha2-->)n, or (-->8Neu5Gcalpha2-->)n. We have partially purified this novel sialidase and compared its reactivity with that of microbial sialidases using four different sialic acid dimers, Neu5Gcalpha2-->5-O(glycolyl)Neu5Gc (Gg2), Neu5Acalpha2-->8Neu5Ac (A2), Neu5Gcalpha2-->8Neu5Gc (G2), and KDNalpha2-->8KDN (K2) as substrates. Hydrolysis was monitored by high performance anion-exchange chromatography with a CarboPac PA-100 column and pulsed amperometric detection, the method by which we can accurately quantitate both the substrate (sialiac acid dimers) and the product (sialic acid monomers). The oyster sialidase effectively hydrolyzed Gg2 and K2, whereas A2 and G2 were poor substrates. Neu5Ac2en but not KDN2en effectively inhibited the hydrolysis of Gg2 by the oyster sialidase. Likewise, the hydrolysis of K2 by the oyster sialidase was inhibited by a cognate inhibitor, KDN2en, but not by Neu5Ac2en. Using the new analytical method we found that Gg2 was hydrolyzed less efficiently than A2 but much more readily than G2 by Arthrobacter ureafaciens sialidase. This result was at variance with the previous report using the thiobarbituric acid method to detect the released free sialic acid [Kitazume, S., et al. (1994) Biochem. Biophys. Res. Commun. 205, 893-898]. In agreement with previous results, Gg2 was a poor substrate for Clostridium perfringens sialidase, while K2 was refractory to all microbial sialidases tested. Thus, the oyster sialidase is novel and distinct from microbial sialidases with regards to glycon- and linkage-specificity. This finding adds an example of the presence of diverse sialidases, in line with the diverse sialic acids and sialic acid linkages that exist in nature. The new sialidase should become useful for both structural and functional studies of sialoglycoconjugates.

Functional analysis and treatment of problem behavior evoked by noise.

We conducted a four-part investigation to develop methods for assessing and treating problem behavior evoked by noise. In Phase 1, 7 participants with developmental disabilities who were described as being hypersensitive to specific noises were exposed to a series of noises under controlled conditions. Results for 2 of the participants verified that noise was apparently an aversive event. In Phase 2, results of functional analyses indicated that these 2 participants' problem behaviors were maintained by escape from noise. In Phase 3, preference assessments were conducted to identify reinforcers that might be used during treatment. Finally, in Phase 4, the 2 participants' problem behaviors were successfully treated with extinction, stimulus fading, and a differential-reinforcement-of-other-behavior (DRO) contingency (only 1 participant required DRO). Treatment effects for both participants generalized to their home environments and were maintained during a follow-up assessment. Procedures and results were discussed in terms of their relevance to the systematic assessment of noise as an establishing operation (EO) and, more generally, to the identification of idiosyncratic EO influences on behavior.

Rapid access to uronic acid-based mimetics of Kdn2en from D-glucurono-6,3-lactone.

A concise route to novel mimetics of Kdn2en, based on delta4-uronic acids, from D-glucurono-6,3-lactone is presented. Uronic acid-based mimetics in which an aliphatic ether (O-glycoside), a thioether (S-glycoside), or acetamide takes the place of the natural C-6 glycerol sidechain of the sialic acid were synthesized from the key intermediate, methyl 2,3,4-tri-O-acetyl-alpha-D-glucopyranosyluronate bromide.

Synthesis of delta4-beta-D-glucopyranosiduronic acids as mimetics of 2,3-unsaturated sialic acids for sialidase inhibition.

Mimetics of Neu5Ac2en and KDN2en, based on delta4-beta-delta-glucopyranosiduronic acids, have been synthesised. The Neu5Ac2en mimetic 5 showed inhibition of both bacterial and viral sialidases, with inhibition of the viral sialidase being comparable to that of Neu5Ac2en itself.

Catalysis by a new sialidase, deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm), initially forms a less stable alpha-anomer of 3-deoxy-D-glycero-D-galacto-nonulosonic acid and is strongly inhibited by the transition state analogue, 2-deoxy-2, 3-didehydro-D-glycero-D-galacto-2-nonulopyranosonic acid, but not by 2-deoxy-2,3-didehydro-N-acetylneuraminic acid.

Deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm) is a new sialidase that has been induced and purified from Sphingobacterium multivorum. Catalysis by this new sialidase has been studied by enzyme kinetics and 1H NMR spectroscopy. Vmax/Km values determined for synthetic and natural substrates of KDNase Sm reveal that 4-methylumbelliferyl-KDN (KDNalpha2MeUmb, Vmax/Km = 0.033 min-1) is the best substrate for this sialidase, presumably because of its good leaving group properties. The transition state analogue, 2, 3-didehydro-2,3-dideoxy-D-galacto-D-glycero-nonulosonic acid, is a strong competitive inhibitor of KDNase Sm (Ki = 7.7 microM versus Km = 42 microM for KDNalpha2MeUmb). 2-Deoxy-2, 3-didehydro-N-acetylneuraminic acid and 2-deoxy-2, 3-didehydro-N-glycolylneuraminic acid are known to be strong competitive inhibitors for bacterial sialidases such as Arthrobacter ureafaciens sialidase; however, KDNase Sm activity is not significantly inhibited by these compounds. This observation suggests that the hydroxyl group at C-5 is important for recognition of the inhibitor by the enzyme. Reversible addition of water molecule (or hydroxide ion) to the reactive sialosyl cation, presumably formed at the catalytic site of KDNase Sm, eventually gives rise to two different adducts, the alpha- and beta-anomers of free 3-deoxy-D-glycero-D-galacto-nonulosonic acid. 1H NMR spectroscopic studies clearly demonstrate that the thermodynamically less stable alpha-form is preferentially formed as the first product of the cleavage reaction and that isomerization rapidly follows, leading to an equilibrium mixture of the two isomers, the beta-isomer being the major species at equilibrium. Therefore, we propose that KDNase Sm catalysis proceeds via a mechanism common to the known exosialidases, but the recognition of the substituent at C-5 by the enzyme differs.

Airway muscle stereology: implications for increased shortening in asthma.

Increased airway smooth muscle, resulting from either hyperplasia or hypertrophy, has been implicated as a cause of excessive bronchoconstriction in asthma despite the many methodologic limitations of studies to date. Our recent failure to demonstrate increased muscle volume in an asthmatic airway preparation having 3-fold greater shortening than nonasthmatic controls prompted us to reassess the quantity of muscle in asthmatic versus nonasthmatic airways. Smooth muscle was quantified in axially sectioned, 2nd- to 4th-generation bronchi, using standardized stereologic methods on high-magnification images of cross-sectional airway smooth muscle profiles in tissues from five asthmatic subjects and five nonasthmatic smokers. When data were normalized by total cross-sectional tissue area, no differences between the two groups (asthmatic versus nonasthmatic) were detected for the proportion of smooth muscle (3.45 +/- 0.81% versus 2.74 +/- 0.76%), extracellular matrix between muscle cells (1.65 +/- 0.46% versus 1.06 +/- 0.25%), or connective tissue within smooth muscle bundles (1.65 +/- 0.34% versus 1.53 +/- 0.59%). These methodologies for evaluating cross-sectional airway muscle in axial airway sections at high resolution provide no evidence of increased airway smooth muscle in asthmatic large airways, and suggest that differences in mechanical responses of asthmatic airways cannot be explained solely by the amount of smooth muscle.

Hypothesis: excessive bronchoconstriction in asthma is due to decreased airway elastance.

Based on the strikingly different mechanical properties of airway smooth muscle preparations of different species, we hypothesized that a decrease in the elastance of nonmuscle elements within airway walls of asthmatics reduces the load limiting smooth muscle shortening, thereby allowing excessive smooth muscle shortening and bronchoconstriction. Full thickness, circumferentially cut, lobar bronchial preparations were obtained from one asthmatic and six nonasthmatic lobectomy subjects. Passive tension of the asthmatic preparation was less than that for any nonasthmatic preparation at all lengths below that for optimal force generation (Lmax). Maximal isometric force generation was greater in the asthmatic specimen (2.32 g) than in the nonasthmatic specimens (0.90 +/- 0.15 g), with stress threefold higher for the asthmatic tissue. Isotonic shortening of the asthmatic preparation was strikingly greater at starting lengths less than or equal to Lmax, with maximal fractional shortening being 31% versus 11 +/- 2% for nonasthmatic preparations. Morphometric analysis revealed no differences in cross-sectional areas of smooth muscle for asthmatic versus nonasthmatic preparations. We conclude that the reduced tissue elastance may account for the greater muscle shortening by placing a lesser load upon the smooth muscle. Airway inflammation in asthma may alter connective tissue matrix elements within airway walls leading to this decreased elastance and excessive smooth muscle shortening.

Role of leukotrienes in airway hyperresponsiveness in guinea-pigs.

1. Repeated aerosolization of leukotriene C4 (LTC4) to guinea-pigs produced leftward shift in their pulmonary resistance (RL) dose-response curves to inhaled acetylcholine (ACh) without increasing the maximum responses. 2. Repeated LTC4 aerosolization did not increase airway eosinophils. 3. The 5-lipoxygenase-activating protein (FLAP) inhibitor, MK-886, prevented the leftward shift in RL dose-response curves to ACh following repeated antigen challenge in guinea-pigs. 4. MK-886 did not inhibit the increased maximal RL produced by repeated antigen challenge, nor inhibit the airway eosinophilia induced by repeated antigen challenge. 5. Our findings suggest that leukotrienes may account for the leftward shift in pulmonary resistance responses caused by antigen but do not cause the airway eosinophilia nor enhanced maximum broncho-constrictor response to antigen.

cis-bis(pyridine)platinum(II) organoamides with unexpected growth inhibition properties and antitumor activity.

The platinum(II) organoamides [Pt(NRCH2)2L2] (L = pyridine (py), R = p-HC6F4, C6F5,p-IC6F4,p-CIC6F4,p-C6F5C6F4; L = 4-methylpyridine, R = p-HC6F4) and [Pt(NRCH2CH2NR')(py)2] (R = p-HC6F4, R' = C6F5, p-BrC6F4, or p-MeC6F4) inhibit the growth of murine L1210 leukemia cells in culture with ID50 values for continuous exposure in the range 0.6-2.7 microM. Representative complexes are also active against L1210 cells in 2-h pulse exposures, as well as against the cisplatin-resistant variant L1210/DDP and human colonic carcinoma cell lines HT 29 and BE. Three complexes [Pt(NRCH2)2L2] (R = p-HC6F4, C6F5, or p-IC6F4) have good activity (T/C greater than or equal to 180%) against P388 leukemia in mice, and all other compounds tested are active except when R = p-C6F5C6F4, L = py. Although the molecular basis of the biological activity of these complexes is not known, the observation of good activity for amineplatinum(II) compounds with no hydrogen substituents on the nitrogen donor atoms introduces a new factor in the anticancer behavior of platinum(II) complexes.

Capsaicin inhibits airway hyperresponsiveness but not lipoxygenase activity or eosinophilia after repeated aerosolized antigen in guinea pigs.

To evaluate the role of tachykinins in airway hyperresponsiveness following repeated aerosolized antigen challenge in guinea pigs, we treated 12 guinea pigs with capsaicin (105.6 mg cumulative dose given subcutaneously over 5 days) after sensitization to ovalbumin (OA) and before three repeated OA aerosol challenges per wk for 4 to 5 wk. Ten guinea pigs received identical OA sensitization and challenges without capsaicin treatment, and four of eight nonsensitized controls received capsaicin followed by saline challenges. Capsaicin treatment did not alter antibody responses to OA as assessed by passive cutaneous anaphylaxis, nor did it alter lipoxygenase products from OA-stimulated bronchial tissue in vitro. Capsaicin completely inhibited the increased pulmonary resistance (RL) to acetylcholine produced by repeated aerosolized OA, whereas it did not alter baseline RL or acetylcholine responses of controls. Capsaicin did not alter airway eosinophilia induced by repeated aerosolized OA. We conclude that neuropeptides play an important role in antigen-induced airway hyperresponsiveness without altering antibody levels, lipoxygenase mediator production, or airway eosinophilia.

Nedocromil sodium inhibits airway hyperresponsiveness and eosinophilic infiltration induced by repeated antigen challenge in guinea-pigs.

1. Repeated exposure to ovalbumin aerosol produced significant increases in epithelial eosinophils of airways of all sizes and produced increased pulmonary resistance (RL) to inhaled acetylcholine (ACh) in guinea-pigs. 2. Nedocromil sodium 10 mg ml-1, by nebulization prior to each ovalbumin (OA) challenge inhibited both the airway eosinophilia and hyperresponsiveness to ACh. 3. Nedocromil sodium pretreatment (10 mg ml-1 by nebulization) 10 min prior to OA completely inhibited the acute bronchoconstrictor response to OA. 4. Our findings suggest that nedocromil sodium inhibits airway hyperresponsiveness by inhibiting eosinophilic infiltration, or by simultaneously inhibiting mechanisms involved in both processes.

Inhibition of antigen-induced airway hyperresponsiveness, but not acute hypoxia nor airway eosinophilia, by an antagonist of platelet-activating factor.

The role of platelet-activating factor (PAF) in Ag-induced airway hyperresponsiveness was evaluated in a guinea pig model using the PAF antagonist SDZ 64-412. Repeated OVA challenge by aerosol (twice weekly x 4 wk) of previously sensitized guinea pigs produced striking airway hyperresponsiveness as determined by pulmonary resistance changes to increasing doses of inhaled acetylcholine given 3 days after the last OVA challenge. Each OVA challenge produced significant hypoxia that was unaffected by oral pretreatment with 20 mg/kg SDZ 64-412, 2 h before each challenge (pO2 = 35 +/- 2 mm Hg for OVA alone vs 40 +/- 6 mm Hg for SDZ and OVA groups, respectively). SDZ 64-412 pretreatment abolished the airway hyperresponsiveness resulting from repeated Ag challenge. Morphometric analysis revealed that SDZ 64-412 treatment had no effect on the increased numbers of eosinophils that infiltrated the airways of OVA-challenged guinea pigs. These results suggest that PAF may be a primary mediator of airway hyperresponsiveness, but not acute bronchoconstriction, induced by repeated Ag challenge. This activity of PAF appears independent of eosinophil recruitment to airways.

Increased in vitro responses of tracheal smooth muscle from hyperresponsive guinea pigs.

Repeated aerosol antigen challenge of previously sensitized guinea pigs induces airway hyperresponsiveness to inhaled acetylcholine. To determine the mechanism producing these airway changes and assuming that changes in the trachealis muscle reflect changes in muscle of the entire tracheobronchial tree, we examined the in vitro smooth muscle mechanics and morphometric parameters of tracheae from guinea pigs demonstrating hyperresponsiveness in vivo vs. tracheae from control guinea pigs. No differences between these groups were found in luminal volume at zero transmural pressure, passive pressure-volume characteristics, or area of airway wall. Smooth muscle areas were slightly less in tracheae from hyperresponsive guinea pigs. Tracheae from hyperresponsive guinea pigs had both significantly increased isovolumetric force generation and isobaric shortening compared with tracheae from controls when evaluated over the range of transmural pressures from -40 to 40 cmH2O. We conclude that the in vivo airway hyperresponsiveness induced with repeated antigen challenge is associated with both increased force generation and shortening of tracheal smooth muscle without increased muscle mass, suggesting enhanced contractile activity.

Repeated antigen challenge induces airway hyperresponsiveness with tissue eosinophilia in guinea pigs.

To test the hypothesis that the development of airway hyperresponsiveness (AHR) lasting greater than or equal to 3 days after the last antigenic exposure required repeated mediator release, we compared dose-response changes in lung resistance (RL) to acetylcholine (ACh) in animals sensitized with 1% ovalbumin (OA), 4% Bordatella pertussis aerosol and subsequently challenged with 0.5% OA aerosol twice weekly for 4-6 wk vs. animals receiving saline aerosol instead of OA. Despite antihistamine pretreatment, each OA challenge produced cyanosis and inspiratory indrawing. Blood gas analysis in six guinea pigs revealed an immediate fall in arterial PO2 (PaO2) from 104.3 +/- 4.9 to 35.4 +/- 2.2 Torr after a 1-min exposure to aerosolized OA. ACh dose-response measurements of RL 3 days after the last OA challenge demonstrated a leftward shift and an increased magnitude of response. These differences were less marked at 7 days, and by 14 days after the last OA challenge, ACh dose-response curves were not different from those of control guinea pigs. Sensitization without repeated antigen challenge did not cause hyperresponsiveness. Morphometric analysis showed significantly increased numbers of eosinophils in the epithelium of airways in hyperresponsive guinea pigs, without neutrophil infiltration or alterations in epithelium and airway wall areas. We conclude that repeated antigenic challenge, but not sensitization alone, causes prolonged AHR in guinea pigs, which is associated with tissue eosinophilia.