Autocrine production of matrix metalloproteinase-2 is required for human airway smooth muscle proliferation

Airway smooth muscle proliferation is important in asthma and is dependent on pro- and antimitogenic factors and cell-matrix interactions. Here we show an antiproliferative effect of protease inhibitors on human airway smooth muscle due to inhibition of autocrine-derived matrix metalloproteinase (MMP)-2. Proliferation in response to fetal bovine serum, thrombin, and platelet-derived growth factor was inhibited by the broad-spectrum protease inhibitor Complete and the MMP inhibitors EDTA and Ro-31-9790 but not by cysteine or serine protease inhibitors. Conditioned medium from airway smooth muscle cells contained 72-kDa gelatinase that was secreted by growth-arrested cells and increased by fetal bovine serum but not by thrombin or platelet-derived growth factor. Immunostaining of cultured human airway smooth muscle cells and normal lung biopsies confirmed this gelatinase to be MMP-2. Our results suggest a novel role for MMP-2 as an important autocrine factor required for airway smooth muscle proliferation. Inhibition of MMPs could provide a target for the prevention of smooth muscle hyperplasia and airway remodeling in asthma.

Selective deletion of antigen-specific, activated T cells by a humanized MAB to CD2 (MEDI-507) is mediated by NK cells

CD2 is a 50-kDa transmembrane glycoprotein that plays an important role in T and natural killer (NT) lymphocyte functions. CD2 serves as both an adhesion molecule and as a costimulatory molecule through interactions with its ligand, CD58, on antigen presenting or target cells. Consistent with earlier studies using a rat anti-CD2 mAb, we have shown that treatment of alloantigen stimulated T lymphocytes with a humanized mAb, MEDI-507 (IgG1, kappa), induced hyporesponsiveness to subsequent stimulation with alloantigen but not to mitogen (phytohemagglutinin). Fluorescence-activated cell sorting analysis of cells from mixed lymphocyte reaction (MLR) treated with MEDI-507 revealed pronounced deletion of T and NK cells, consistent with lack of proliferation in the MLR. MEDI-507 F(ab')2 fragments did not have inhibitory activity or induce deletion of lymphocytes in the MLR. Removal of the NK cell subset by magnetic bead depletion using anti-CD16 and anti-CD56 mAbs eliminated both the T cell deletion and the inhibitory effect. Reconstitution of NK depleted responder populations using autologous NK cells restored the MEDI-507-mediated deletion activity to levels measured in the original MLR. Formaldehyde-fixed NK cells failed to mediate the MEDI-507-induced deletion effect. Altogether, our studies indicate that activated T cells with MEDI-507 bound to CD2 are preferential targets for autologous NK cells through a nonapoptotic cytotoxic mechanism.

Epidemics of diarrhea caused by a clindamycin-resistant strain of Clostridium difficile in four hospitals

BACKGROUND

Large outbreaks of diarrhea caused by a newly recognized strain of Clostridium difficile occurred in four hospitals located in different parts of the United States between 1989 and 1992. Since frequent use of clindamycin was associated with the outbreak in one of the hospitals, we examined the resistance genes of the epidemic-strain isolates and studied the role of clindamycin use in these outbreaks.

METHODS

Case-control studies were performed at three of the four hospitals to assess the relation of the use of clindamycin to C. difficile-associated diarrhea. All isolates of the epidemic strain and representative isolates of other strains identified during each outbreak were tested for susceptibility to clindamycin. Chromosomal DNA from these representative isolates was also analyzed by dot blot hybridization and amplification with the polymerase chain reaction (PCR) with the use of probes and primers from a previously described determinant of erythromycin resistance - the erythromycin ribosomal methylase B (ermB) gene - found in C. perfringens and C. difficile.

RESULTS

In a stratified analysis of the case-control studies with pooling of the results according to the Mantel-Haenszel method, we found that the use of clindamycin was significantly increased among patients with diarrhea due to the epidemic strain of C. difficile, as compared with patients whose diarrhea was due to nonepidemic strains (pooled odds ratio, 4.35; 95 percent confidence interval, 2.02 to 9.38; P<0.001). Exposure to other types of antibiotics or hospitalization in a surgical ward was not significantly associated with the risk of C. difficile-associated diarrhea due to the epidemic strain. All epidemic-strain isolates were highly resistant to clindamycin (minimal inhibitory concentration, >256 microg per milliliter). DNA hybridization and PCR analysis showed that all these isolates had an ermB gene, which encodes a 23S ribosomal RNA methylase that mediates resistance to macrolide, lincosamide, and streptogramin antibiotics. Only 15 percent of the nonepidemic strains were resistant to clindamycin.

CONCLUSIONS

A strain of C. difficile that is highly resistant to clindamycin was responsible for large outbreaks of diarrhea in four hospitals in different states. The use of clindamycin is a specific risk factor for diarrhea due to this strain. Resistance to clindamycin further increases the risk of C. difficile-associated diarrhea, an established complication of antimicrobial use.

Effect of gradual accumulation of iron, molybdenum and sulfur, slow depletion of zinc and copper, ethanol or fructose ingestion and phlebotomy in gout

Gout affects mostly males over 40 years old and, occasionally, postmenopausal women. This pattern coincides with the pattern of iron accumulation. On the other hand, menstruating women are seldom afflicted by gout, because the monthly blood loss causes them to accumulate iron to a much lesser degree. Gout involves seven aspects: (1) uric acid overproduction from increased purines in the diet; (2) uric acid overproduction from ATP degradation; (3) uric acid overproduction from increased de novo synthesis of purines; (4) uric acid overproduction from increased DNA breakdown from cell damage; (5) decreased uric acid elimination, caused by molybdenum and sulfur binding to copper in the kidneys; (6) precipitation of sodium urate-iron crystals in the joints due to high ferritin and saturated transferrin and low CuZn-SOD and Cu-thionein in the joint; (7) development of inflammation, triggered by tyrosine bonding to the sodium-urate-iron crystals and being transformed by tyrosine kinase. Alcohol and iron greatly affect most of these aspects. Therefore, phlebotomy is suggested as therapy for gout patients, in order to eliminate the accumulated Fe. Furthermore, yearly blood donation is recommended for males with a family history of gout, so as to prevent Fe accumulation and avoid gout.

Practice parameters for the treatment of restless legs syndrome and periodic limb movement disorder. An American Academy of Sleep Medicine Report. Standards of Practice Committee of the American Academy of Sleep Medicine

These are the first clinical guidelines published for the treatment of Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) providing evidence-based practice parameters. They were developed by the Standards of Practice Committee and reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine. The guidelines provide recommendations for the practice of sleep medicine in North America regarding the treatment of RLS and PLMD. Recommendations are based on the accompanying comprehensive review of the medical literature regarding treatment of RLS and PLMD which was developed by a task force commissioned by the American Academy of Sleep Medicine. Recommendations are identified as standards, guidelines, or options, based on the strength of evidence from published studies that meet criteria for inclusion. Dopaminergic agents are the best studied and most successful agents for treatment of RLS and PLMD. Specific recommendations are also given for the use of opioid, benzodiazepine, anticonvulsant, and adrenergic medications, and for iron supplementation. In general, pharmacological treatment should be limited to individuals who meet diagnostic criteria and especially who experience insomnia and/or excessive sleepiness that is thought to occur secondary to RLS or PLMD. Individuals treated with medication should be followed by a physician and monitored for clinical response and adverse effects. It would be desirable for future investigations to employ multicenter clinical trials, with expanded numbers of subjects using double-blind, placebo-controlled designs, and an assessment of long-term response, side effects, and impact of treatment on quality of life. Evaluation of special groups such as children, pregnant women, and the elderly is warranted.

Emergency department observation of poisoned patients: how long is necessary?

OBJECTIVE

To compare the emergency physician disposition decisions after observation periods of two, four, and six hours in a single cohort of ED patients with acute intentional ingestion to determine the accuracy of disposition decisions at two and four hours relative to the six-hour period of observation.

METHODS

This was a prospective observational study at two university hospital EDs. Study participants were patients with potentially toxic oral ingestions occurring less than six hours prior to ED presentation. Patients with isolated recreational drug or ethanol use were excluded. Structured data forms were completed at presentation, and two, four, and six hours later. Data included signs and symptoms consistent with toxic ingestion, physical examination, laboratory determinations, medications ingested, treatment, and suicide risk. At two and four hours, physicians were asked to determine whether they thought the patient was safe for medical clearance. These patients continued to be observed for six hours. The main outcome was whether patients initially thought to be appropriate for early medical clearance were ultimately cleared at six hours.

RESULTS

There were 260 patients enrolled: 28 were immediately admitted to the hospital and 17 were immediately discharged; 215 entered ED observation. Patients had a mean age of 24 years; 55% were female; 50% were suicidal; 17% had toxidromes. Of the 215 observed patients, 106 (49%) were deemed safe for early medical clearance at two hours. All 106 were ultimately cleared at six hours (100%, 95% CI = 97% to 100%). Of the 109 not safe for early medical clearance at two hours, 61 (56%) were deemed safe for early medical clearance at four hours; all 61 were subsequently discharged at six hours (100%; 95% CI = 95% to 100%). Overall, 167 of 215 (77%) observed overdose patients were deemed safe for early medical clearance after two or four hours of observation. All 167 were ultimately cleared at six hours (100%; 95% CI = 98.2% to 100%).

CONCLUSIONS

A large subset of overdose patients who are medically cleared after six hours of observation can be identified within two to four hours of presentation. No patient who was believed to be safe for medical clearance at either two or four hours had a complication within the six-hour time period (95% CI = 0% to 1.8%). These data suggest that asymptomatic patients with selected acute intentional ingestions can be released from medical observation in less than six hours.

Screening for hand osteoarthritis (OA) using a postal survey

OBJECTIVE

The aim of this study was to determine the feasibility of screening for hand osteoarthritis (OA) using a postal survey.

METHODS

Men and women aged 40-79, selected at random from a general practice in Nottingham, were sent a postal survey concerning arm pain. Subjects were asked to identify presence of any nodes, based on a diagrammatic example, and to document specific distal (DIP) and proximal (PIP) nodes. One hundred and thirty-nine subjects were subsequently assessed by a nurse metrologist, blinded to the subjects assessment. Subject-observer agreement was measured by calculating unweighted kappa (kappa). In addition, sensitivity and specificity were calculated, taking observer-identified nodes as the 'gold standard'. Intraobserver reproducibility was assessed on 10 subjects with nodes.

RESULTS

Intraobserver reproducibility was reasonable at all sites (kappa>/=0.59). Of the 56 subjects with observer-identified 'any nodes', 40 subjects had correctly identified them (sensitivity 71.4%); with three subjects incorrectly identifying nodes (specificity 96.4%). Corresponding kappa was 0.70. Subject-observer agreement was higher for presence/absence of any DIP nodes than PIP nodes (kappa=0.67 and 0.36 respectively). As with nodes overall, specificity was high (100% and 96.6% respectively). Agreement was generally poor for specific joint involvement.

CONCLUSION

A postal survey is a useful screening tool for identifying subjects with nodes. Although sensitivity may not be sufficient to permit assessment of prevalence of hand OA in the community, it has potential applications in terms of identifying and defining cases for further study.

Interstitial pneumonitis following mitozantrone, chlorambucil and prednisolone (MCP) chemotherapy

We describe two cases of interstitial lung disease in patients with non-Hodgkin's lymphoma who were treated with combination chemotherapy including mitozantrone. In both we had radiological and histological evidence of interstitial lung disease, with patterns of organizing pneumonia and hypersensitivity without a clear aetiological agent. Clinical resolution occurred on withdrawal of chemotherapy. One patient required a course of corticosteroid treatment. To date, both patients are well and in remission, and there has been no recurrence of their respiratory disease. We postulate that these observations are hitherto undescribed pulmonary abnormalities secondary to mitozantrone therapy.

Practice parameters for the use of light therapy in the treatment of sleep disorders. Standards of Practice Committee, American Academy of Sleep Medicine

These clinical guidelines were developed by the Standards of Practice Committee and reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine. The guidelines provide recommendations for the practice of sleep medicine in North America regarding the use of light therapy for treatment of various sleep disorders. This paper is based on a series of articles in the Journal of Biological Rhythms and also includes evidence tables from an updated Medline review covering the period January 1994 to December 1997. Evidence is presented by grade and level. Recommendations are identified as standards, guidelines, or options. Recommendations are provided for delayed sleep phase syndrome (DSPS), advanced sleep phase syndrome (ASPS), non-24-hour sleep-wake syndrome, jet lag, shift work, dementia, and sleep complaints in the healthy elderly. Light therapy appears generally safe if used within recommended intensity and time limits. Light therapy can be useful in treatment of DSPS and ASPS. Benefits of light therapy are less clear and treatment is an option in jet lag, shift work, and non-24-hour sleep-wake syndrome in some blind patients.

The care pathway: a tool to enhance clinical governance

A care pathway defines in detail the individual components of treatment for a group of patients. A well-written pathway can lead to consistent care of the highest quality. There are both educational and audit advantages to the approach. The authors detail the means by which groups are selected and the care pathways written. An example of the benefits that can accrue comes from their experience at Ashford Hospital of running a pathway for patients having prostate surgery. The pathways are appreciated by patients, nurses, doctors and managers. Care is improved, costs contained and clinical governance enhanced.

A direct comparison of the activities of two humanized respiratory syncytial virus monoclonal antibodies: MEDI-493 and RSHZl9

Two humanized monoclonal antibodies, MEDI-493 and RSHZ19, were developed independently as potential improvements over RSV-IGIV for prevention of respiratory syncytial virus (RSV) infection. RSV-IGIV is a polyclonal human antibody preparation for intravenous infusion enriched for RSV neutralizing activity. A phase III clinical trial showed that MEDI-493 significantly reduced hospitalizations due to RSV infection. In a separate trial, RSHZ19 failed to show significant efficacy. In new studies, the in vitro and in vivo activities of MEDI-493 and RSHZ19 were compared to determine whether the different clinical results are related to differences in biologic activity. MEDI-493 was consistently 4- to 5-fold more potent than RSHZ19 in antigen binding, RSV neutralization, and fusion inhibition assays. Although both MEDI-493 and RSHZ19 were effective against A and B subtypes of RSV in the cotton rat model of RSV infection, 2- to 4-fold higher doses of RSHZ19 were required for similar protection. The enhanced activity of MEDI-493 compared with RSHZ19 may, in part, explain its better clinical effect.

Changes in the morphology and the distribution of rat intestinal eosinophils during infection with the nematode Nippostrongylus brasiliensis

Increases in the numbers of eosinophil leukocytes present in the lamina propria of intestines infected with nematodes is a well described phenomenon, yet the role of these leukocytes and their actions in this situation are not yet fully understood. Morphologic changes in these cells occur with the course of the infection, as do alterations in their location within the gut; these findings may give important clues to the function of this prominent cell. We observed changes in intestinal eosinophils in the August rat during infection with the nematode Nippostrongylus brasiliensis and found, together with the well known increases in number infiltrating the lamina propria at Day 20 (three times the levels in normal animals), a distinct change in the morphology of individual cells which included increase of the cell's overall size and changes in shape, as well as a dissemination of cytoplasmic granules in relationship to the cell's nucleus. No ultrastructural evidence of extracellular degranulation or intact eosinophil cytoplasmic granules outside the bounds of cell cytoplasmic membranes was seen. This finding is important considering the light microscopic appearance of individual eosinophil granules apparently distributed extracellularly, and lying in the connective tissue of the lamina propria, a common histopathologic observation in eosinophilic conditions. Eosinophils within the lamina propria changed their location as the infection progressed, tending to move to line up along the subepithelial zones. In addition, eosinophils were observed both at the light and electron microscopic levels to be passing through the basement membrane and into the epithelial layer. This latter phenomenon was confirmed using confocal optical slicing where eosinophils were commonly observed on the luminal side of the nuclei of the gut epithelium. These observations strongly suggest that morphologic alterations occur in eosinophils in the lamina propria and these changes may be associated with functional alterations in these cells akin to the putative phenomenon of "activation." Our findings indicate that eosinophils have the capacity to enlarge and extend their cytoplasmic processes between various components of the lamina propria and move toward the basement membrane during an active infection, as well as into, and possibly through, the intestinal epithelium. These findings emphasize the need for careful consideration of the changing morphologic status of eosinophils when investigating biologic changes associated with the activation of these cells in tissue inflammatory responses.

Phase I trial of multiple cycles of high-dose chemotherapy supported by autologous peripheral-blood stem cells

PURPOSE

To determine the safety and feasibility of delivering multiple cycles of front-line high-dose carboplatin and paclitaxel with hematopoietic peripheral-blood stem cell (PBSC) support.

PATIENTS AND METHODS

Patients were required to have a malignant solid tumor for which they had received no prior chemotherapy. Mobilization of PBSC was achieved with cyclophosphamide, etoposide, and granulocyte-macrophage colony-stimulating factor (GM-CSF). After one cycle of conventional-dose carboplatin and cyclophosphamide with GM-CSF, patients received multiple cycles of high-dose carboplatin (area under the concentration-time curve [AUC], 12 to 20) and paclitaxel (250 mg/m(2)) with PBSC and GM-CSF repeated every 28 days.

RESULTS

Twenty-four of 28 patients were assessable for toxicity and clinical outcome. Dose-limiting toxicities were dehydration, diarrhea, and electrolyte imbalances. The maximum-tolerated dose of carboplatin was AUC 16 (equivalent to a median of 1,189 mg/m(2)). The relationship of target AUC to measured AUC was linear (r(2) =. 29; P =.0011). The overall response rate was 96%, with a complete clinical response rate of 67%. The median time to progression from the first PBSC reinfusion was 49.5 weeks (range, 8 to 156+ weeks).

CONCLUSION

Multiple cycles of high-dose carboplatin (AUC 16) and paclitaxel (250 mg/m(2)) can be safely administered with GM-CSF and PBSC support. Although this regimen is safe, feasible, and active, the use of multiple cycles of high-dose chemotherapy as front-line treatment remains experimental and should only be used in the context of a clinical trial.

Improving support for mental health staff: a qualitative study

BACKGROUND

High levels of both burnout and job satisfaction have been found in recent studies of mental health professionals. A qualitative methodology was used in a related study to explore reasons for these findings and to investigate staff's accounts of their strategies for coping with their work, and their views of support provided for them and how their jobs might be made less stressful and still more satisfying.

METHOD

A semi-structured schedule was used to interview a purposive sample of 30 mental health staff drawn from three South London geographical sectors, selected to include junior and senior members of each profession in both hospital and community settings. Interviews were transcribed and analysed using QSR NUD.IST software.

RESULTS

Informal contacts with colleagues were the most frequently mentioned way of coping with the difficult and demanding aspects of work in both hospital and community settings, closely followed by time management techniques. The main formal sources of support described by staff were individual supervision and staff support groups. Accounts of the former were generally positive, but there was great variation in opinions about whether support groups are useful. Almost all the interviewees believed that their jobs could be improved by further training. For community mental health staff the main training gaps were the development of skills in various forms of clinical intervention, whilst ward staff identified the need for further skills in diffusing potentially confrontational and aggressive situations.

Explanations for stress and satisfaction in mental health professionals: a qualitative study

BACKGROUND

High levels of burnout and poor psychological well-being, but also relatively high levels of job satisfaction, have been found among mental health staff, especially those based in community settings.

AIMS

In order to investigate the basis of these findings, a qualitative interview study was carried out, exploring mental health staff's views of their work and of its effects on them.

METHOD

A semi-structured interview was administered to a purposive sample of 30 professionals, including junior and senior members of each profession in both hospital and community settings. Interviews were transcribed verbatim and analysed using QSR NUD.IST software.

RESULTS

For most professionals, contact with colleagues was one of the major rewards of the job. There was surprisingly little evidence of conflict or difficulties defining roles between disciplines, except for the social workers, for whom difficulty in defining roles in relation to other professions was a major preoccupation. Reported stresses differed between community and hospital staff. Community staff tended to find their contacts with patients highly rewarding, but also to feel burdened by a strong and uncomfortable sense of being constantly responsible for their clients' well-being and actions. Ward staff, on the other hand, identified as central difficulties in their job lack of autonomy, responsibility and scope for developing an independent therapeutic role. They felt demoralised by revolving door' patients and by violence and the need to restrain patients.

Mental health, "burnout" and job satisfaction in a longitudinal study of mental health staff

BACKGROUND

This study examines whether the adoption of a more community based model in an inner city psychiatry service is accompanied by increasing "burnout", deteriorating mental health and decreasing job satisfaction amongst staff.

METHOD

Questionnaires were sent annually for 3 consecutive years to all mental health staff working in three adult mental health sectors in inner London. Main outcome measures were the 12-item General Health Questionnaire, Maslach Burn-out Inventory and a general job satisfaction measure.

RESULTS

There was no significant change over time in the outcome measures, once confounding by job and demographic variables was examined. Being based in the community was associated with higher GHQ-12 scores (P = 0.02) when compared to in-patient staff over the 3 years.

CONCLUSIONS

These results suggested that working in the community may be more stressful than working in in-patient services. However, there was no evidence to suggest that levels of stress are increasing over time, either in community-based or hospital-based staff.

Globular domains of agrin are functional units that collaborate to induce acetylcholine receptor clustering

Agrin, an extracellular matrix protein involved in neuromuscular junction formation, directs clustering of postsynaptic molecules, including acetylcholine receptors (AChRs). This activity resides entirely in the C-terminal portion of the protein, which consists of three laminin-like globular domains (G-domains: G1, G2 and G3) and four EGF-like repeats. Additionally, alternate mRNA splicing yields G-domain variants G2(0,4) with 0- or 4-amino-acid inserts, and G3(0, 8,11,19) with 0-, 8-, 11- or 19-amino-acid inserts. In order to better understand the contributions of individual domains and alternate splicing to agrin activity, single G-domains and covalently linked pairs of G-domains were expressed as soluble proteins and their AChR clustering activity measured on cultured C2 myotubes. These analyses reveal the following: (1) While only G3(8) exhibits detectable activity by itself, all G-domains studied (G1, G2(0), G2(4), G3(0) and G3(8)) enhance G3(8) activity when physically linked to G3(8). This effect is most pronounced when G2(4) is linked to G3(8) and is independent of the order of the G-domains. (2) The deletion of EGF-like repeats enhances activity. (3) Increasing the physical separation between linked G1 and G3(8) domains produces a significant increase in activity; similar alterations to linked G2 and G3(8) domains are without effect. (4) Clusters induced by two concatenated G3(8) domains are significantly smaller than all other agrin forms studied. These data suggest that agrin G-domains are the functional units which interact independently of their specific organization to yield AChR clustering. G-domain synergism resulting in biological output could be due to physical interactions between G-domains or, alternatively, independent interactions of G-domains with cell surface receptors which require spatially localized coactivation for optimal signal transduction.