Occurrence and risk factors for falls in rheumatoid arthritis

OBJECTIVES

To determine the one year period prevalence of falls by age and sex in patients with rheumatoid arthritis and the influence of concurrent medical treatment and disability on the occurrence of falls in this group.

METHODS

A consecutive series of rheumatoid patients aged 35 years and over, attending hospital outpatient clinics at Hope hospital, Salford, were asked to complete an interview assisted questionnaire which asked about the occurrence and number of falls in the previous 12 months.

SUBJECTS

who took part were asked about current treatment with antihypertensive agents, diuretics, sedatives or hypnotics, antidepressants, and a history of previous hip/knee surgery. They also completed the health assessment questionnaire (HAQ). Logistic regression was used to determine the association between these variables and falls in the previous 12 months.

RESULTS

253 men and women, mean age 62 years, were studied, and 84 (33%) reported falling in the previous year (36% of women and 26% of men). Of these, 52% had fallen on more than one occasion. There was no important increase in the frequency of falls with age. After adjusting for age and sex, those who had fallen in the previous year were more likely to report taking antidepressant treatment (odds ratio (OR) = 2.09) and to have impairment in both walking (OR = 1.37) and rising (OR = 1.41). The HAQ score was higher in those who reported a fall than those who did not, though the difference was not statistically significant.

CONCLUSIONS

In this hospital based survey, one in three patients with rheumatoid arthritis reported falling in the previous 12 months. Falls were associated with self reported impairment in lower limb function.

Benzocaine-Induced Methemoglobinemia: A Condition of which all Endoscopists Should Be Aware

Methemoglobinemia is a rare complication that can occur with the use of benzocaine-containing compounds. Two cases of methemoglobinemia are reported, and the pathophysiology and treatment of methemoglobinemia are reviewed. Both patients received topical 20% benzocaine spray before endoscopy. Immediately following the procedure, there was a reduction in O2saturation assessed by pulse oximetry that was refractory to O2therapy. Dramatic peripheral and central cyanosis developed. O2saturation measured by pulse oximetry ranged from 83% to 87% on O2by nasal prongs and 100% O2by a nonrebreathing mask. Both patients were mildly confused and one patient complained of a significant headache. The diagnosis of methemoglobinemia was considered and arterial blood gas sampling was performed. In both patients, the arterial blood had a chocolate brown colour. A methemoglobin level of 48% and 18% was noted in patient 1 and patient 2, respectively. Both patients were treated with methylene blue, resulting in a significant improvement with gradual normalization of their O2saturation within 10 min to 30 min. The use of benzocaine spray may not markedly alter the patient's perception of endoscopy and thus, the routine use of these agents should be questioned. If such agents are used, the physician must be aware of this association to prevent a delay in the diagnosis and management of this rare, but potentially lethal, condition.

Cre/lox-mediated marker gene excision in transgenic maize (Zea mays L.) plants

After the initial transformation and tissue culture process is complete, selectable marker genes, which are used in virtually all transformation approaches, are not required for the expression of the gene of interest in the transgenic plants. There are several advantages to removing the selectable marker gene after it is no longer needed, such as enabling the reuse of selectable markers and simplifying transgene arrays. We have tested the Cre/ lox system from bacteriophage P1 for its ability to precisely excise stably integrated marker genes from chromosomes in transgenic maize plants. Two strategies, crossing and autoexcision, have been tested and demonstrated. In the crossing strategy, plants expressing the Cre recombinase are crossed with plants bearing a transgene construct in which the selectable marker gene is flanked by directly repeated lox sites. Unlike previous reports in which incomplete somatic and germline excision were common, in our experiments complete somatic and germline marker gene excision occurred in the F(1) plants from most crosses with multiple independent Cre and lox lines. In the autoexcision strategy, the cre gene, under the control of a heat shock-inducible promoter, is excised along with the nptII marker gene. Our results show that a transient heat shock treatment of primary transgenic callus is sufficient for inducing cre and excising the cre and nptII genes. Genetic segregation and molecular analysis confirmed that marker gene removal is precise, complete and stable. The autoexcision strategy provides a way of removing the selectable marker gene from callus or other tissues such as embryos and kernels.

Effects of cis-nonachlor, trans-nonachlor and chlordane on the immune system of Sprague-Dawley rats following a 28-day oral (gavage) treatment

The immunotoxicity of cis- and trans-nonachlor and chlordane were investigated in adult male and female Sprague-Dawley rats following a 28-day oral (gavage) treatment. Rats were randomly assigned to six experimental groups: cis-nonachlor, females; trans-nonachlor, females; technical chlordane females; cis-nonachlor, males; trans-nonachlor, males; technical chlordane, males. The immunologic endpoints included: quantification of the total serum immunoglobulin (Ig) levels and subclasses and flow cytometric analysis of peripheral blood leukocytes and T-lymphocyte subsets, evaluation of the lymphoproliferative activity of splenocytes in response to concanavalin A (Con A) and Salmonella typhimurium (STM) mitogens, and natural killer (NK) cell activity of splenocytes. Satellite experiments to examine the delayed-type hypersensitivity (DTH) response to oxazolone, and resistance to Listeria monocytogenes were set up for female rats treated with cis- or trans-nonachlor. Statistically significant (P<0.05) effects included: increased serum immunoglobulin M (IgM) levels in the chlordane-treated females at the 25 mg/kg dose (pairwise comparison); increased serum IgG(1) and IgG(2c) in the cis-nonachlor-treated males at the 2.5 and 25 mg/kg doses and increased serum IgG(2a) levels at all doses; increased serum IgG(2b) at the 25 mg/kg dose and decreased (dose-related) serum IgM levels in the cis-nonachlor-treated male rats; increased (linear trend) IgG(1) and IgG(2a) in the cis-nonachlor-treated females with effects on IgG(2a) significant at the 25 mg/kg dose compared with control; increased serum IgG(2a) in the trans-nonachlor-treated male and female rats at the 2.5 mg/kg dose; increased absolute numbers (linear trend) of peripheral white blood cells, B lymphocytes, natural killer (NK) cells, T-suppressor/cytotoxic lymphocytes, and the double positive (T-helper/inducer, T-suppressor/cytotoxic) cells in the trans-nonachlor-treated females; increased (non-linear trend) lymphoproliferative activity in the Con A-stimulated splenocytes and decreased (linear trend) activity in the S. typhimurium mitogen-stimulated splenocytes of the cis-nonachlor-treated females; reduced resistance to L. monocytogenes in the cis-nonachlor (day 3, P=0.034)- and trans-nonachlor (day 2, P=0.0001)-treated females, and reduced (linear trend) NK cell activity in the cis-nonachlor-treated males. The present data indicated that the chlordane compounds tested in this study had significant effects on a number of immunologic endpoints. In comparison to technical chlordane, cis- and trans-nonachlors were more immunotoxic. Therefore, an evaluation of the risk these chlorinated compounds may pose to human health should consider the potential effects different chlordane compounds may have on the immune system.

Selective Purkinje cell ectopia in the cerebellum of the weaver mouse

The adult mouse cerebellar vermis consists of four transverse zones, each of which is further subdivided into parasagittal stripes. In the adult weaver (wv/wv) mouse, the zebrin II expression pattern in the cerebellar vermis is abnormal, consistent with the absence of a central zone (approximately lobules VI/VII). Because the small, heat shock protein HSP25 is a constitutive marker of parasagittal bands of Purkinje cells in the caudal central zone and the nodular zone (approximately lobules IX/X), we used HSP25 immunocytochemistry to show that the patterning abnormalities in wv/wv reflect selective Purkinje cell ectopia rather than the absence of the central zone. A specific HSP25-immunopositive Purkinje cell ectopia within the central zone was identified. Symmetrical clusters of HSP25-immunopositive Purkinje cells, which presumably would have formed the parasagittal stripes in the wild type, are present ectopically on either side of the midline in wv/wv. In contrast, in the nodular zone, HSP25-immunopositive Purkinje cells form a near-monolayer and are organized into parasagittal stripes. We therefore conclude that specific Purkinje cell clusters in the wv/wv cerebellum fail to disperse and that this ectopia contributes to the topographical abnormalities.

Sciatic inflammatory neuritis (SIN): behavioral allodynia is paralleled by peri-sciatic proinflammatory cytokine and superoxide production

We have recently developed a model of sciatic inflammatory neuritis (SIN) to assess how immune activation near peripheral nerves influences somatosensory processing. Administration of zymosan (yeast cell walls) around a single sciatic nerve produces dose-dependent low-threshold mechanical allodynia without thermal hyperalgesia. Low (4 microg) doses produce both territorial and extraterritorial allodynia restricted to the injected hindleg. In contrast, higher (40 microg) doses produce territorial and extraterritorial allodynias of both hindlegs, an effect not accounted for by systemic spread of the zymosan. The aim of these experiments was to determine whether these behavioral allodynias were correlated with immunological and/or anatomical changes in or around the sciatic nerve. These experiments reveal that zymosan-induced bilateral allodynia was associated with the following: (a) increased release of both interleukin-1beta and tumor necrosis factor-alpha from peri-sciatic immune cells; (b) increased release of reactive oxygen species from perisciatic immune cells; (c) no change in circulating levels of proinflammatory cytokine; (d) no apparent zymosan-induced influx of immune cells into the sciatic nerve from the endoneurial blood vessels; (e) mild edema of the sciatic, which was predominantly restricted to superficial regions closest to the peri-sciatic immune cells; and (f) no anatomic evidence of changes in either the ipsilateral saphenous nerve or contralateral sciatic nerve that could account for the appearance of extraterritorial or contralateral ("mirror") allodynia, respectively. No reliable differences were found when the low-dose zymosan was compared with vehicle controls. Taken together, these data suggest that substances released by peri-sciatic immune cells may induce changes in the sciatic nerve, leading to the appearance of bilateral allodynia.

Dilated and defunct K channels in the absence of K+

Potassium ions are vital for maintaining functionality of K channels. In their absence, many K channel types enter a long-lasting defunct condition characterized by absence of conductance and drastic changes in gating current. We show that channels pass through a dilated condition with altered selectivity as they are becoming defunct. To characterize these abnormalities we examined gating and ionic currents generated by Shaker IR and by three nonconducting mutants, W434F, D447N, and Y445A, in 0 K+. On entering the dilated condition, Shaker IR becomes permeable to Na+ and tetramethylammonium-positive (TMA+), signaling deformation of the selectivity filter. When dilated, nearly normal closing is possible at -140 mV. At -80 mV, however, closing is very slow and channels stray from the dilated into the defunct condition. Restoration from defunct to dilated condition requires tens of seconds at 0 mV and can occur in the absence of K+. W434F and D447N are similar to Shaker IR, showing Na+ and TMA+ permeability when dilated. The defunct gating currents are similar in Shaker IR and these two mutants and are reminiscent of the early transitions of normal gating. Y445A does not become defunct and shows Na+ but not TMA+ permeability on K+ removal.

Measurement of the electric form factor of the neutron through d-->(e-->,e(')n)p at Q2 = 0.5 (GeV/c)(2)

We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).

Effects of MAP kinase cascade inhibitors on the MKK5/ERK5 pathway

Antibodies that recognise the active phosphorylated forms of mitogen-activated protein kinase (MAPK) kinase 5 (MKK5) and extracellular signal-regulated kinase 5 (ERK5) in untransfected cells have been exploited to show that the epidermal growth factor (EGF)-induced activation of MKK5 and ERK5 occurs subsequent to the activation of ERK1 and ERK2 in HeLa cells. The drugs U0126 and PD184352, which prevent the activation of MKK1 (and hence the activation of ERK1/ERK2), also prevent the activation of MKK5, although higher concentrations are required. Our studies define physiological targets of the MKK5/ERK5 pathway as proteins whose phosphorylation is largely prevented by 10 microM PD184352, but unaffected by 2 microM PD184352. Surprisingly, 2 microM PD184352 prolongs the activation of MKK5 and ERK5 induced by EGF or H(2)O(2), indicating negative control of the MKK5/ERK5 pathway by the classical MAPK cascade. Our results also indicate that ERK5 is not a significant activator of MAPK-activated protein kinase-1/RSK in HeLa cells.

The role of alpha-MSH as a modulator of cutaneous inflammation

Among various neuropeptides such as substance P, calcitonin gene-related peptide and others, alpha-melanocyte-stimulating hormone (alpha-MSH) was found to be produced in the skin. Moreover, melanocortin receptor 1 (MC-1R), which is specific for alpha-MSH and ACTH, is expressed in the skin on keratinocytes, dendritic cells, macrophages and endothelial cells. In monocytes, macrophages and dendritic cells alpha-MSH inhibits the production and activity of immunoregulatory and proinflammatory cytokines such as IL-2, IFN-gamma, TNF-alpha and IL-1. It downregulates the expression of costimulatory molecules such as CD86 and CD40 and induces the production of suppressor factors such as the cytokine synthesis inhibitory factor IL-10. On endothelial cells alpha-MSH is capable of downregulating the LPS-induced expression of adhesion molecules such as vascular cell adhesion molecule (VCAM) and E-selectin. Moreover, the LPS-induced activation of transcription factors such as NF kappa B is downregulated by alpha-MSH. In a mouse model i.v. or topical application of alpha-MSH was found to inhibit the induction phase as well as the effector phase of contact hypersensitivity (CHS) reactions and to induce hapten-specific tolerance. These findings indicate that the production of immunosuppressing neuropeptides such as alpha-MSH by epidermal cells may play an essential role during the pathogenesis of immune and inflammatory reactions in the skin.

Isolation and characterization of mouse MUC18 cDNA gene, and correlation of MUC18 expression in mouse melanoma cell lines with metastatic ability

The cell surface adhesion molecule human MUC18 (huMUC18 or Mel-CAM) has been postulated to play a key pathogenic role in metastatic melanoma progression. To establish an immunocompetent syngeneic mouse model that would greatly facilitate our understanding of the role of MUC18 in the metastatic behavior of melanoma, we cloned and characterized the mouse MUC18 (muMUC18) cDNA gene. The gene was amplified by RT-PCR and RACE of the poly(A)+RNA isolated from the mouse melanoma cell line B16F10/Queens. The cloned muMUC18 cDNA gene contained 28 nucleotides of 5'-UTR, 908 nucleotides of 3'-UTR, and an open reading frame (ORF) of 1947 nucleotides encoding a protein of 648 amino acids, which is two amino acids longer than huMUC18. The size of the muMUC18 mRNA is about 3 kb with a shorter 3'-UTR than the huMUC18 mRNA (about 3.3 kb). Besides, the sequence in the 3' UTR of the two mRNAs is diverse with only 31% identity. The 5'-UTR and coding sequences of the muMUC18 cDNA are 72.4 and 80.6% identical to those of huMUC18, respectively. The deduced amino acid sequence of the muMUC18 cDNA is 76.2% identical to that of huMUC18. The amino acid sequences deduced from MUC18 cDNA sequences from six other mouse melanoma cell lines are identical except one to three residues, suggesting that the muMUC18 cDNA sequence determined in this report is correct. The muMUC18 protein is predicted to be slightly more acidic than the human protein. The levels of muMUC18 mRNA and protein in nine mouse melanoma cell lines were directly proportional to their ability to establish metastatic colonies in lungs of syngeneic mice. Most biological functions of the muMUC18 may be similar to the huMUC18.

Measurement of the charged pion electromagnetic form factor

Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in the momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of the invariant mass W = 1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parametrization fitted to very low Q2 elastic data.

Comparative effects of metal chelating agents on the neuronal cytotoxicity induced by copper (Cu+2), iron (Fe+3) and zinc in the hippocampus

The ability of metal chelating agents to prevent neuronal death caused by intra-hippocampal injections of cupric sulphate, ferric citrate and zinc chloride was investigated. Ammonium tetrathiomolybdate was itself toxic after injection into the hippocampus, but this toxicity was reduced by formation of a metal ion/tetrathiomolybdate complex with Cu+2. Disodium bathocuproine disulphonate (BCDS) prevented neuronal death caused by Cu+2, but not that induced by Fe+3 or Zn+2. Desferrioxamine prevented death caused by Fe+3, had no significant effect of the toxicity of Zn+2, and increased that caused by Cu+2. Even though N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) has a higher affinity for Cu+2 than for Zn+2, TPEN had no effect on the toxicity of Cu+2 while totally preventing damage caused by Fe+3 or Zn+2. Ethylenediaminetetra-acetic acid (EDTA) prevented the toxicity of all three metal ions. Motor seizure activity occurred in most rats after injections of Fe+3; or combinations of Cu+2 plus TPEN, or 4 nmol Fe+3 plus 0.1 nmol desferrioxamine. However, apart from the low dose desferrioxamine/Fe+3 combination, only the occasional brain contained seizure-induced neuronal loss in limbic regions outside the injected hippocampus, and these brains were not used for analysis. Seizure activity was found even with very low levels of Cu+2 with a fixed amount of TPEN (a ratio of Cu+2/TPEN of 1:100), but the extent of hippocampal damage in these brains was not significantly different to that caused by injections of saline. These studies demonstrate that idiosyncratic interactions can occur between metal ions and chelating agents. Thus further investigations are needed before chelating agents can be examined for their protective properties in various neurodegenerative diseases.

What is the most promising strategy for the treatment of metastasizing melanoma?

The treatment of patients with metastasizing melanoma, still one of the most deadly diseases in modern medicine, ranks among the greatest challenges that a clinician has to face. Metastatic melanoma also is one of the most profound sources of clinical frustration, since it provides far more ultimately defeating experiences than clinical victories. At the same time, the fascinating biology of melanoma has invited the study of this neuroectodermal tumor as a model system for dissecting many of the key problems of modern oncology, ranging from molecular oncogenesis via the controls of tumor proliferation, apoptosis, invasion, metastasis, and angiogenesis to tumor immunosurveillance and tumor drug resistance. Together with the dire need to develop more effective treatment modalities for improving both life expectancy and quality of life of affected patients, this has made metastatic melanoma a favorite model for the exploration of innovative strategies for tumor management. Encouragingly, many of these have already generated very promising results in animal models. However, this impressive level of research progress in conquering melanoma in the animal room contrasts rather pitifully with the actual progress made on the ward. This CONTROVERSIES feature, therefore, critically and soberly reviews the state of the art of treating metastatic melanoma today (distinguishing between nodal and distant metastases), and sharply defines unresolved or comparatively neglected key problems. In addition, this feature highlights several novel, provocative, hitherto underappreciated, yet potentially promising treatment approaches that deserve systematic exploration. Hopefully, this will offer further inspiration for the design and pursuit of innovative anti-melanoma strategies off-the-beaten-track.