Treatment of osteoarthritis of the hip and knee: a comparison of NSAID use in patients for whom surgery was and was not recommended.

OBJECTIVE: To determine if NSAID use was different between OA (hip and/or knee) patients treated surgically to those treated medically. METHODS: We conducted a case control study, in which cases (n = 433) had had a total joint replacement within a two-year period, while controls (n = 195) had seen a rheumatologist or orthopedic surgeon, and not been recommended for surgery. Current and previous NSAID use was surveyed. RESULTS: Cases were older than controls (70 vs. 64 years, p < 0.0001), and were more likely to have OA in the hips (45% vs. 21%, p < 0.0001), to have severe OA (p < 0.0001), and to be male (42% vs. 28%, p < 0.0008). Potential confounding variables were statistically adjusted using logistic regression. Although disease duration was similar in cases and controls (9.8 years), cases had tried fewer NSAIDs (1.3 +/- 0.05 vs. 2.3 +/- 0.08 in controls, p < 0.0001). Cases were less likely to have taken any NSAID (86% vs. 94% of controls; OR 0.40, p < 0.007) or to have had intra-articular steroids (OR 0.19, p < 0.0001). Two or more NSAIDs were used (ever) in 38% of cases vs. 70% of controls (p < 0.0001); and 3 or more NSAIDs in 5% vs. 38% (p < 0.0001). Women were less apt to have obtained total joint replacements (OR 0.62, p < 0.0001), including TKRs even when adjusting for severity of OA. CONCLUSIONS: NSAIDs are used less by orthopedic surgeons than rheumatologists in our centre. Some subjects were offered a joint replacement without even a failure of medical management. The reasons for differences in prescribing trends are unknown. Referral biases may exist.

Haemophilus influenzae - human specific bacteria.

Haemophilus influenzae is both a commensal and a pathogen specific to humans. Here we review this bacterium with special emphasis on characteristics that may be involved in virulence.

SdrG, a fibrinogen-binding bacterial adhesin of the microbial surface components recognizing adhesive matrix molecules subfamily from Staphylococcus epidermidis, targets the thrombin cleavage site in the Bbeta chain.

Staphylococcus epidermidis is an important opportunistic pathogen and is a major cause of foreign body infections. We have characterized the ligand binding activity of SdrG, a fibrinogen-binding microbial surface component recognizing adhesive matrix molecules from S. epidermidis. Western ligand blot analysis showed that a recombinant form of the N-terminal A region of SdrG bound to the native Bbeta chain of fibrinogen (Fg) and to a recombinant form of the Bbeta chain expressed in Escherichia coli. By analyzing recombinant truncates and synthetic peptide mimetics of the Fg Bbeta chain, the binding site for SdrG was localized to residues 6-20 of this polypeptide. Recombinant SdrG bound to a synthetic 25-amino acid peptide (beta1-25) representing the N terminus of the Fg Bbeta chain with a KD of 1.4 x 10(-7) m as determined by fluorescence polarization experiments. This was similar to the apparent K(D) (0.9 x 10(-7) m) calculated from an enzyme-linked immunosorbent assay where SdrG bound immobilized Fg in a concentration-dependent manner. SdrG could recognize fibrinopeptide B (residues 1-14), but with a substantially lower affinity than that observed for SdrG binding to synthetic peptides beta1-25 and beta6-20. However, SdrG does not bind to thrombin-digested Fg. Thus, SdrG appears to target the thrombin cleavage site in the Fg Bbeta chain. In fact, SdrG was found to inhibit thrombin-induced fibrinogen clotting by interfering with fibrinopeptide B release.

2-36[K4,RYYSA(19-23)]PP a novel Y5-receptor preferring ligand with strong stimulatory effect on food intake.

Members of the neuropeptide Y (NPY) family regulate many physiological processes via interaction with at least four functional, pharmacologically distinct Y-receptors. However, selective antagonists developed for several subtypes have not been useful in defining particular Y-receptor functions in vivo. To identify critical residues within members of the NPY family required for Y-receptor subtype-selectivity we have determined the contribution of each residue within NPY to receptor binding by replacing them with L-alanine. In a second study, chimeric peptides where single or stretches of residues were interchanged between members of the NPY family were generated and tested in radioligand binding studies. Overall, substituted alanine analogues exhibited similar orders of affinities at each Y-receptor subtype with no obvious subtype-selectivity. Residues of particular interest are Leu30 which exhibited selectivity for the Y4-receptor, whereas Asp16 does not appear to play any role in ligand binding. Several chimeric peptides, e.g., [K4]pancreatic polypeptide ([K4]PP) and [RYYSA(19-23)]PP clearly showed higher affinity at the Y4 and Y5 subtypes compared to the Y1 and Y2 subtypes. In addition, the transfer of a proline residue from position 14 to 13 in peptide YY decreases its affinity at the Y1-, Y4- and Y5-receptors but is unchanged at the Y2 subtype. Combining these results, and with the help of molecular modelling, second generation chimeras were designed. The most significant improvement was achieved in chimera 2-36[K4,RYYSA(19-23)]PP where the affinity for the Y5 subtype increased by ninefold over that from NPY. Several of these compounds were also tested for their ability to stimulate food intake in a rat model. Interestingly, again 2-36[K4,RYYSA(19-23)]PP showed the most dramatic effect with a major increase on food intake over a range of doses compared to NPY suggesting a possible synergistic effect of several Y-receptors on feeding behaviour.

Immunologic and structural relationships of the minor pilus subunits among Haemophilus influenzae isolates.

Two proteins, HifD and HifE, have been identified as structural components of Haemophilus influenzae pili. Both are localized at the pilus tip, and HifE appears to mediate pilus adherence to host cells. In this study we examined the immunologic and structural diversity of these pilus subunits among type b H. influenzae (Hib) and nontypeable H. influenzae (NTHI) strains. Western immunoblot analysis revealed that antibodies directed against the C terminus of HifD and HifE from Hib strain Eagan bound to HifD and HifE proteins, respectively, of all piliated Hib and NTHI strains tested. Whole-cell enzyme-linked immunosorbent assays showed that antibodies specific for native HifD or HifE of strain Eagan also bound to all piliated Hib strains but did not bind to the piliated NTHI strains. Antibodies against HifE of strain Eagan inhibited the binding of Hib to human erythrocytes but did not inhibit the binding of NTHI strains. Restriction fragment length polymorphism (RFLP) analysis was used to determine strain-to-strain structural differences within hifD and hifE genes, either by PCR or by nucleotide sequence analysis. DNA and derived amino acid sequence analyses of HifD and HifE confirmed the uniqueness of the RFLP types. The hifD and hifE genes of all type b strains showed identical restriction patterns. Analysis of hifD and hifE genes from the NTHI strains, however, revealed seven unique RFLP patterns, suggesting that these genes encode proteins with diverse primary structures. These results indicate that HifD and HifE are immunologically and structurally similar among the Hib strains but vary among the NTHI strains.

Identification of two minor subunits in the pilus of Haemophilus influenzae.

Haemophilus influenzae type b (Hib) organisms produce pili, which mediate attachment to human cells and are multimeric structures composed of a 24-kDa subunit called pilin or HifA. Although pili from other organisms contain additional proteins accessory to pilin, no structural components other than pilin have been identified in Hib pili. Previous analysis of a Hib pilus gene cluster, however, suggested that two genes, hifD and hifE, may encode additional pilus subunits. To determine if hifD and hifE encode pilus components, the genes were overexpressed in Escherichia coli and the resulting proteins were purified and used to raise polyclonal antisera. Antisera raised against C-terminal HifD and HifE fragments reacted with H. influenzae HifD and HifE proteins, respectively, on Western immunoblots. Western immunoblot analysis of immunoprecipitated Hib pili demonstrated that HifD and HifE copurified with pili. In enzyme-linked immunosorbent assays, antisera raised against a recombinant HifE protein that contained most of the mature protein reacted more to piliated Hib than to nonpiliated Hib or to a mutant containing a hifE gene insertion. Immunoelectron microscopy confirmed that the HifE antiserum bound to pili and demonstrated that the antiserum bound predominantly to the pilus tips. These data indicate that HifD and HifE are pilus subunits. Adherence inhibition studies demonstrated that the HifE antiserum completely blocked pilus-mediated hemagglutination, suggesting that HifE mediates pilus adherence.

Comparison of duration of agonist action at beta 1- and beta 2- adrenoceptors in C6 glioma cells: evidence that the long duration of action of salmeterol is specific to the beta 2-adrenoceptor.

The C6 glioma cell line, which expresses beta 1- and beta 2-adrenoceptors at a ratio of 80:20, was used to investigate the durations of action of formoterol at beta 1-adrenoceptors and of salmeterol at both beta 1- and beta 2-adrenoceptors in an attempt to determine whether the sustained duration of action of salmeterol was unique to beta 2-adrenoceptors or, as with formoterol, resulted from its lipophilic nature and partitioning into the bulk lipid of the plasma membrane. In this cell line, formoterol, like the nonselective beta-adrenoceptor agonist isoprenaline, behaved as a potent, full agonist at beta 1-adrenoceptors and did not seem to exhibit a high degree of selectivity for beta 2-adrenoceptors. Salmeterol seemed to stimulate cAMP accumulation in C6 cells predominantly via activation of the subpopulation of beta 2-adrenoceptors. However, at high (micromolar) agonist concentrations, salmeterol also activated beta 1-adrenoceptors, albeit with low potency and efficacy. At high concentrations (30 microM), salmeterol attenuated cAMP responses mediated by activation of beta 1-adrenoceptors by isoprenaline (Kp = 1.6 microM), indicating that salmeterol exhibited a low affinity for beta 1-adrenoceptors in C6 cells. In multiple washout experiments, cAMP responses to isoprenaline and formoterol waned with increasing numbers of washing processes. Therefore, it seemed that formoterol relied on its moderately lipophilic nature to partition into bulk lipid of the plasma membrane to produce sustained activity, particularly at high agonist concentrations. Salmeterol was found to persist at beta 2-adrenoceptors in C6 cells despite washing cell monolayers up to four times. To determine the duration of action of salmeterol at beta 1-adrenoceptors expressed on the same cells, use was made of full/partial agonist interactions. In cells exposed to a single washout of agonist-containing medium, salmeterol (30 microM) lost its ability to attenuate responses to the more efficacious agonist, isoprenaline. This observation provided convincing evidence to support the hypothesis that salmeterol exhibits sustained agonist activity at beta 2-adrenoceptors, but not beta 1-adrenoceptors, expressed on the same cells. Therefore, the sustained activity of salmeterol at beta 2-adrenoceptors seems to be unique and does not result solely from its partitioning into bulk lipid of the plasma membrane.

Identification of hifD and hifE in the pilus gene cluster of Haemophilus influenzae type b strain Eagan.

Haemophilus influenzae produces surface structures called pili that promote adherence to human cells. Three genes encoding the major pilus structural component (pilin), chaperone, and usher proteins (designated hifA, -B, and -C, respectively) have been identified previously. In this study, transposon mutagenesis and DNA sequence analysis identified two open reading frames (ORFs) downstream of, and in the same orientation as, hifC. These genes have been designated hifD and hifE. Both genes have predicted C-terminal amino acid homology to HifA, and mutations in either gene resulted in the loss of morphologic and functional pili, indicating that hifD and hifE encode pilus structural components and are required for pilus expression. Another ORF, identified immediately downstream of hifE, has a predicted amino acid sequence that is 70% identical to an aminopeptidase of Escherichia coli called PepN, and a mutation within this ORF did not alter pilus expression. These data indicate that the pepN homolog is not required for pilus biogenesis and that one end of the pilus gene cluster has been defined.

Dysregulation of airway cytokine expression in chronic obstructive pulmonary disease and asthma.

Cigarette smoking is the major factor responsible for chronic obstructive pulmonary disease (COPD). COPD occurs in a minority of smokers, but the host factors that modify risk of disease have not been clearly elucidated. There is significant clinical and histopathologic overlap between COPD and asthma, including the accumulation and activation of airway inflammatory cells. These two disorders are compared and contrasted. Abnormal airway inflammatory cytokine expression in these disorders is discussed.

Altered cytokine regulation in the lungs of cigarette smokers.

Cigarette smoking is the major factor responsible for chronic obstructive lung disease, but it occurs in only a minority of smokers. Smoking is associated with increased susceptibility to pulmonary infections and with a neutrophil- and macrophage-rich inflammation of the small airways. We compared concentrations of tumor necrosis factor (TNF), interleukin (IL)-6, and IL-8 in bronchoalveolar lavage fluid (BALF) and measured the capacity of BALF macrophages to release TNF and IL-6 in vitro in nine smokers (19.1 +/- 4.2 pack-years; mean +/- SE) and nine nonsmokers. Compared with nonsmokers, BALF from smokers contained more cells (65.3 +/- 13.2 versus 27.2 +/- 4.8 x 10(6); p < 0.02), but much lower concentrations of IL-6 (1.8 +/- 1.0 versus 15.9 +/- 5.8 pg/ml; p < 0.05). The two smokers with the highest number of BALF cells had increased BALF concentrations of interleukin-8 (IL-8), but there was no difference in BALF IL-8 concentrations between the two groups (p = 0.08). Compared with BALF macrophages from nonsmokers, cells from smokers released less TNF (211 +/- 77 versus 1,406 +/- 348 units per 10(8) cells; p < 0.01) and IL-6 (5.8 +/- 2.6 versus 64.9 +/- 23.3 hybridoma units per ml; p < 0.02) during a 6-h incubation with lipopolysaccharide (LPS). We conclude that even in young, healthy smokers the pulmonary microenvironment is markedly abnormal, characterized by depressed levels of IL-6, macrophages that have a markedly depressed capacity for LPS-induced cytokine release and, in some smokers, increased concentrations of IL-8.

Increased activity of interleukin-6 but not tumor necrosis factor-alpha in lung lavage of premature infants is associated with the development of bronchopulmonary dysplasia.

Although considerable evidence suggests that bronchopulmonary dysplasia (BPD) is the result of prolonged inflammation and impaired healing of the immature lung, the mediators that regulate inflammation in neonatal lung injury have not been completely elucidated. We examined whether the cytokines IL-6 and tumor necrosis factor-alpha (TNF) interact to modulate a cascade of cell-cell signaling events involved in inflammation contributing to the development of BPD. To determine the relative activities of these cytokines in neonatal lung injury, lung lavage samples were serially obtained from 1 to 28 d from 11 infants with self-limited respiratory distress syndrome (RDS), 19 infants with evolving BPD, and 10 control infants ventilated for nonpulmonary reasons. On the first day of life, there were no differences in antigenic IL-6 concentrations in lavage fluids among the BPD, RDS, and control groups, but IL-6 activity determined by the 7TD1 proliferation assay was 15-fold and 6.6-fold higher in lung lavage of infants who developed BPD compared with activities in lavage from control and RDS infants, respectively (control, 49.4 +/- 17.6; RDS, 117.3 +/- 59.6; BPD, 779.5 +/- 212.6 x 10(3) hybridoma units/L, mean +/- SEM, p = 0.02). This suggests that pathways for inactivating or inhibiting IL-6 that may be present in the lungs of RDS and control infants may be deficient in BPD infants. IL-6 activity remained elevated in lavage of BPD infants for the first 2 wk and declined to low levels by d 28.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of hyperthermia on macrophage interleukin-6 and tumor necrosis factor-alpha expression.

The pyrogenic cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) appear in the circulation during infections and injuries, but TNF-alpha and IL-6 are regulated differently in macrophages. We compared the effects of elevated temperatures within the usual febrile range on the expression of TNF-alpha and IL-6 in vitro in lipopolysaccharide (LPS)-stimulated human macrophages derived from peripheral blood monocytes (HuMoM phi). During an 18-h incubation at 37 degrees C with 5 ng/ml LPS, these cells released 5,030 +/- 1,460 pg TNF-alpha/10(6) cells (means +/- SE) and 1,380 +/- 280 pg IL-6/10(6) cells. In LPS-stimulated HuMoM phi incubated at 40 degrees C, TNF-alpha release was almost completely inhibited (76 +/- 76 pg TNF-alpha/10(6) cells; P < 0.01 compared with LPS-stimulated HuMoM phi at 37 degrees C), but release of IL-6 was preserved (1,600 +/- 780 pg IL-6/10(6) cells). Western and Northern analyses showed that levels of TNF-alpha mRNA and cell-associated and secreted TNF-alpha protein were decreased, but IL-6 expression was unchanged at 40 degrees C in LPS-stimulated macrophages. Incubating HuMoM phi at 40 degrees did not alter their viability after 18 h but induced a 75-fold increase in levels of the inducible heat-shock protein 72 (HSP-72) mRNA in the face of a 56% inhibition in total protein synthesis. Our results show that IL-6 expression persisted at incubation temperatures in the upper end of the physiological range that induced heat shock and attenuated the expression of functionally active TNF-alpha in LPS-stimulated HuMoM phi.

Identification of a gene essential for piliation in Haemophilus influenzae type b with homology to the pilus assembly platform genes of gram-negative bacteria.

Haemophilus influenzae type b (Hib) pili are complex filamentous surface structures consisting predominantly of pilin protein subunits. The gene encoding the major pilin protein subunit of Hib adherence pili has been cloned and its nucleotide sequence has been determined. In order to identify specific accessory genes involved in pilus expression and assembly, we constructed isogenic Hib mutants containing insertional chromosomal mutations in the DNA flanking the pilin structural gene. These mutants were screened for pilin production, pilus expression, and hemagglutination. Pili and pilin production were assessed by immunoassays with polyclonal antisera specific for pilin and pili of Hib strain Eagan. Hemagglutination was semiquantitatively evaluated in a microtiter plate assay. Six Hib mutants produced proteins immunoreactive with antipilin antiserum but no longer produced structures reactive with antipilus antiserum. In addition, the mutants were unable to agglutinate human erythrocytes. Nucleotide sequence analysis localized the insertion sites in the six mutants to 2.5-kb open reading frame upstream of the pilin structural gene and immediately downstream of an Hib pilin chaperone gene. The amino acid sequence encoded by this open reading frame has significant homology to members of the pilus assembly platform protein family, including FhaA of Bordetella pertussis, MrkC of Klebsiella pneumoniae, and the Escherichia coli assembly platform proteins FimD and PapC. This open reading frame, designated hifC, appears to represent a gene essential to Hib pilus biogenesis that has genetic and functional similarity to the pilus platform assembly genes of other gram-negative rods.

Salmeterol, a long-acting beta 2-adrenoceptor agonist mediating cyclic AMP accumulation in a neuronal cell line.

1. The accumulation of cyclic AMP stimulated by salmeterol, a long-acting beta 2-adrenoceptor agonist and by isoprenaline, a non-selective beta-adrenoceptor agonist have been compared in the B50 neuroblastoma cell line. 2. Salmeterol produced a concentration-dependent increase in the accumulation of total [3H]-cyclic AMP in B50 cells yielding an EC50 value of 37 nM which was lower than that obtained with isoprenaline (294 nM). The maximum response to salmeterol was only 46% of that obtained with isoprenaline. 3. The beta 2-adrenoceptor antagonist, ICI 118551, inhibited the responses to both salmeterol (apparent KD 2.2 nM) and isoprenaline (apparent KD 1.6 nM). However, the beta 1-adrenoceptor antagonist, atenolol, produced no significant effect at concentrations up to 100 microM. 4. Salmeterol (1 microM) changed the concentration-response curve of isoprenaline in the manner of a partial agonist interacting with a full agonist. The KD of salmeterol obtained from the interaction was 55.6 nM. 5. Whereas salmeterol has a slow onset of action in airway smooth muscle compared to other beta 2-adrenoceptor agonists, in B50 monolayers both salmeterol and isoprenaline produced a rapid increase in cyclic AMP accumulation (t1/2 1.1 min and 0.4 min respectively). 6. Despite the existence of cyclic AMP efflux mechanisms that exist in this cell line it was possible to investigate the duration of agonist action by measuring intracellular levels of the second messenger. Replacement of drug-containing medium with fresh buffer led to a rapid reduction in intracellular levels of cyclic AMP in isoprenaline-stimulated cells whereas cyclic AMP accumulation was sustained for much longer periods in salmeterol-stimulated cells. However, the persistent action of salmeterol could be reversed by the addition of a beta2-selective antagonist.7. These results confirm that salmeterol has a high affinity, but low efficacy (relative to isoprenaline) for beta2-adrenoceptors coupled to cyclic AMP accumulation and that the drug persists at its site of action for long periods in the B50 neuronal cell line.

Upregulation of nicotinic receptors following continuous infusion of nicotine is brain-region-specific.

Rats receiving 4 mg nicotine/kg/day via implanted minipumps sustained plasma nicotine concentrations of 40 ng/ml throughout two weeks of nicotine infusion. Numbers of brain [3H]nicotine binding sites were increased by about 50% in cortex and hippocampus whereas numbers of [3H]nicotine binding sites in striatum were unaffected by nicotine treatment at either of the timepoints examined (7, 14 days). Cortical [125I] alpha-bungarotoxin and [3H]QNB binding sites were also unchanged. The regional selectivity of nicotinic receptor modulation may reflect the low dose of nicotine used and the mode of administration. The changes observed may be pertinent to the continuous administration of nicotine in man, via transdermal nicotine patches.

Reactivity of antibodies against conserved regions of pilins of Haemophilus influenzae type b.

To identify epitopes on pilins of Haemophilus influenzae type b (Hib) that may also be immunologically available on assembled pili, antisera were developed against eight synthetic peptides that represent conserved and hydrophilic regions of Hib pilin. Seven of the eight peptides were immunogenic. Binding of the anti-peptide antibodies to purified pili of Hib strain Eagan was weak. However, when the purified pili were denatured by heating, binding of the anti-peptide antibodies improved considerably, suggesting that the epitopes defined by the peptides were more available for anti-peptide antibody binding on the denatured pilins than on purified pili. On Western blot analysis, strain variation was seen in the binding of some of the anti-peptide antibodies, notably those directed against peptides in the N-terminal half of the pilin. Thus, when pilins are assembled into pili, the epitopes defined by the seven immunogenic peptides appear to be altered so that binding of the anti-peptide antibodies is greatly reduced.

Effect of dietary phosphoric acid supplementation on acid-base balance and mineral and bone metabolism in adult cats.

Experimental evidence indicates that maintenance of urinary pH < or = 6.4 is the single most effective means of preventing feline struvite crystalluria or urolithiasis of noninfectious causes. This may be accomplished by dietary acidification, but must be moderated to avoid potential adverse effects of excessive acidification, including bone demineralization, negative calcium balance, potassium depletion, and renal disease. Effects of chronic dietary phosphoric acid supplementation on acid-base balance and on mineral and bone metabolism were investigated in adult, domestic cats. One group of 6 cats was fed a basal, naturally acidifying diet without added acidifiers, and another group of 6 cats was fed 1.7% dietary phosphoric acid. Changes observed during 12 months of study included development of noncompensated metabolic acidosis, increased urinary calcium excretion, and lower but positive calcium balance in cats of both groups. Urinary pH decreased in cats of both groups, but was significantly (P < 0.05) and consistently maintained < or = 6.4 in cats given dietary phosphoric acid. Urinary phosphorus excretion increased in cats of both groups, but was significantly (P < 0.05) greater in phosphoric acid-supplemented cats, leading to lower overall phosphorus balance as well. Potassium balance decreased in cats of both groups, but was only transiently negative in the phosphoric acid-supplemented cats midway through the study, and normalized at positive values thereafter. Plasma taurine concentration was not affected by dietary acidification, and remained well within the acceptable reference range for taurine metabolism. Double labeling of bone in vivo with fluorescent markers was followed by bone biopsy and histomorphometric measurement of several static and dynamic variables of bone formation. Overall indices of bone formation decreased in cats of both groups with age and confinement, but were not affected by dietary phosphoric acid supplementation. Dietary supplementation with phosphoric acid used as the principal inorganic P source to achieve moderate and stable degree of urinary acidification, did not appear over the course of 1 year, to have induced adverse effects on mineral, bone, or taurine balance in these adult domestic cats.