Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana

The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

Practice parameters for the nonpharmacologic treatment of chronic insomnia. An American Academy of Sleep Medicine report. Standards of Practice Committee of the American Academy of Sleep Medicine

Insomnia is the most common sleep complaint reported to physicians. Treatment has traditionally involved medication. Behavioral approaches have been available for decades, but lack of physician awareness and training, difficulty in obtaining reimbursements, and questions about efficacy have limited their use. These practice parameters review the current evidence with regards to a variety of nonpharmacologic treatments for insomnia. Using a companion paper which provides a background review, the available literature was analyzed. The evidence was graded by previously reported criteria of the American Academy of Sleep Medicine with references to American Psychological Association criteria. Treatments considered include: stimulus control, progressive muscle relaxation, paradoxical intention, biofeedback, sleep restriction, multicomponent cognitive behavioral therapy, sleep hygiene education, imagery training, and cognitive therapy. Improved experimental design has significantly advanced the process of evaluation of nonpharmacologic treatments for insomnia using guidelines outlined by the American Psychological Association (APA). Recommendations for individual therapies using the American Academy of Sleep Medicine recommendation levels for each are: Stimulus Control (Standard); Progressive Muscle Relaxation, Paradoxical Intention, and Biofeedback (Guidelines); Sleep Restriction, and Multicomponent Cognitive Behavioral Therapy (Options); Sleep Hygiene Education, Imagery Training, and Cognitive Therapy had insufficient evidence to be recommended as a single therapy. Optimal duration of therapy, who should perform the treatments, long term outcomes and safety concerns, and the effect of treatment on quality of life are questions in need of future research.

Vinorelbine (Navelbine) in the treatment of non-small-cell lung cancer: studies with single-agent therapy and in combination with cisplatin

Initial studies of vinorelbine (Navelbine) given as a single agent to patients with operable non-small-cell lung cancer (NSCLC) showed that overall response rates of the order of 30% could be obtained with a schedule of 30 mg/m2 given weekly. Although such high levels of response have seldom been obtained when vinorelbine is given alone in one arm of a comparative study, the level of activity is clearly worthwhile and represents a significant improvement over supportive care. Combination therapy with cisplatin has been highly successful, establishing Vinorelbine as a safe well-tolerated agent which provides considerable activity, and experience from large phase III studies suggests that the combination of vinorelbine and cisplatin could represent a reference schedule against which other therapy should be compared.

Vinorelbine (navelbine) in the treatment of non-small-cell lung cancer: recent developments in combination chemotherapy and radiotherapy

The investigation of the activity of vinorelbine in non-small-cell lung cancer (NSCLC) has continued beyond the initial studies which established its single agent activity and defined the combination of vinorelbine and cisplatin as one of the standard treatments for inoperable NSCLC. Alternative partners to cisplatin have been evaluated in combination therapy with vinorelbine with promising results emerging from combinations with carboplatin, ifosfamide, mitomycin C and gemcitabine. Three drug combinations such as vinorelbine, cisplatin and ifosfamide can clearly produce high response rates in patients with good performance status at the time of treatment. The ability of vinorelbine to contribute to disease reduction either alone or in combination with other cytotoxic drugs has made it possible to consider its use in neo-adjuvant therapy, while the synergistic action of vinorelbine with radiotherapy has encouraged the use of sequential or concomitant chemoradiotherapy producing high response rates after completion of both modalities. The possible role of post-operative adjuvant treatment with Vinorelbine either alone or in combination with cisplatin is being assessed in a prospective trial.

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.