Angiogenesis gene therapy: phase I assessment of direct intramyocardial administration of an adenovirus vector expressing VEGF121 cDNA to individuals with clinically significant severe coronary artery disease

BACKGROUND

Therapeutic angiogenesis, a new experimental strategy for the treatment of vascular insufficiency, uses the administration of mediators known to induce vascular development in embryogenesis to induce neovascularization of ischemic adult tissues. This report summarizes a phase I clinical experience with a gene-therapy strategy that used an E1(-)E3(-) adenovirus (Ad) gene-transfer vector expressing human vascular endothelial growth factor (VEGF) 121 cDNA (Ad(GV)VEGF121.10) to induce therapeutic angiogenesis in the myocardium of individuals with clinically significant coronary artery disease.

METHODS AND RESULTS

Ad(GV)VEGF121.10 was administered to 21 individuals by direct myocardial injection into an area of reversible ischemia either as an adjunct to conventional coronary artery bypass grafting (group A, n=15) or as sole therapy via a minithoracotomy (group B, n=6). There was no evidence of systemic or cardiac-related adverse events related to vector administration. In both groups, coronary angiography and stress sestamibi scan assessment of wall motion 30 days after therapy suggested improvement in the area of vector administration. All patients reported improvement in angina class after therapy. In group B, in which gene transfer was the only therapy, treadmill exercise assessment suggested improvement in most individuals.

CONCLUSIONS

The data are consistent with the concept that direct myocardial administration of Ad(GV)VEGF121.10 to individuals with clinically significant coronary artery disease appears to be well tolerated, and initiation of phase II evaluation of this therapy is warranted.

The SQUIRE (Standards for QUality Improvement Reporting Excellence) guidelines for quality improvement reporting: explanation and elaboration

As the science of quality improvement in health care advances, the importance of sharing its accomplishments through the published literature increases. Current reporting of improvement work in health care varies widely in both content and quality. It is against this backdrop that a group of stakeholders from a variety of disciplines has created the Standards for QUality Improvement Reporting Excellence, which we refer to as the SQUIRE publication guidelines or SQUIRE statement. The SQUIRE statement consists of a checklist of 19 items that authors need to consider when writing articles that describe formal studies of quality improvement. Most of the items in the checklist are common to all scientific reporting, but virtually all of them have been modified to reflect the unique nature of medical improvement work. This "Explanation and Elaboration" document (E & E) is a companion to the SQUIRE statement. For each item in the SQUIRE guidelines the E & E document provides one or two examples from the published improvement literature, followed by an analysis of the ways in which the example expresses the intent of the guideline item. As with the E & E documents created to accompany other biomedical publication guidelines, the purpose of the SQUIRE E & E document is to assist authors along the path from completion of a quality improvement project to its publication. The SQUIRE statement itself, this E & E document, and additional information about reporting improvement work can be found at http://www.squire-statement.org.

Protection against experimental Staphylococcus aureus arthritis by vaccination with clumping factor A, a novel virulence determinant

The importance of the fibrinogen-binding adhesin clumping factor A (ClfA) in the pathogenesis of Staphylococcus aureus septic arthritis was examined in an animal model. The protective effect of active and passive immunization with ClfA also was investigated in S. aureus infection models. The severity of arthritis was markedly reduced in mice challenged intravenously with a clfA mutant, compared with mice infected with the wild-type strain. Mice immunized with recombinant ClfA and challenged with S. aureus developed less-severe arthritis than did mice immunized with a control antigen. Passive immunization of mice with rat and rabbit anti-ClfA antibodies protected against S. aureus arthritis and sepsis-induced death, indicating that the protection by active immunization is antibody mediated. Taken together, these data strongly suggest that ClfA is a crucial virulence determinant for septic arthritis and an excellent target for the generation of immune therapies directed against S. aureus.

Virulence of protein A-deficient and alpha-toxin-deficient mutants of Staphylococcus aureus isolated by allele replacement

The gene coding for protein A (spa) of Staphylococcus aureus 8325-4 has been inactivated by substituting part of the spa coding sequence for a DNA fragment specifying resistance to ethidium bromide. The in vitro-constructed spa::EtBrr substitution mutation was introduced into the S. aureus chromosome by recombinational allele replacement. Southern blot hybridization showed that the in vitro-constructed mutation was present in the chromosomal spa locus. We have previously reported the inactivation of the alpha-toxin gene (hly) by allele replacement with an in vitro-constructed hly::Emr (erythromycin resistance) mutation (M. O'Reilly, J.C.S. de Azavedo, S. Kennedy, and T.J. Foster, Microb. Pathogen. 1:125-138, 1986). A double Spa- Hly- mutant was constructed by transduction. The virulence of Spa- and Hly- mutants was tested by experimental infection of mice. When subcutaneous injections were given, Hly- mutants formed a flat, darkened lesion, whereas Hly+ strains caused a raised, cream lesion. Alpha-toxin was shown to be a major factor in forming subcutaneous lesions and in causing the death of mice injected intraperitoneally. Spa- mutants were slightly less virulent than their Spa+ counterparts, which suggests that protein A is also a virulence factor of S. aureus.

Mental disorders and suicide in Northern Ireland

BACKGROUND

The aim of this part of the Northern Ireland Suicide Study was to investigate the prevalence of DSM-III-R axis I (clinical syndrome) and axis II (personality) disorders among suicides (14 years and older) in Northern Ireland during a one-year period.

METHOD

A psychological autopsy study based on a variety of documentary sources and interviews with bereaved informants and health care professionals.

RESULTS

Ninety per cent of suicides (106/118) had a current axis I and/or an axis II mental disorder. At least one current axis I disorder was diagnosed in 86% of suicides (102/118), and at least one axis II disorder was diagnosed in 44% (52/118). Suicides under 30 years (92% male) were less likely to have a current axis I disorder (68%; 26/38) than those 30 years and older (95%; 76/80). Psychiatric comorbidity was present in 55% of suicides (65/118). The time between the last contact with a health care professional and death was greater among suicides under 30 years and male suicides.

CONCLUSIONS

Notwithstanding the aetiological complexity of suicide, the prevention, recognition and treatment of mental disorder will continue to play key roles in suicide prevention.

Conservation of the regulatory subunit for the Clp ATP-dependent protease in prokaryotes and eukaryotes

Bacteria, tomatoes, and trypanosomes all contain genes for a large protein with extensive homology to the regulatory subunit, ClpA, of the ATP-dependent protease of Escherichia coli, Clp. All members of the family have between 756 and 926 amino acids and contain two large regions, of 233 and 192 amino acids, each containing consensus sequences for nucleotide binding. Within these regions there is at least 85% similarity between the most distant members of the family. The high degree of similarity among the ClpA-like proteins suggests that Clp-like proteases are likely to be important participants in energy-dependent proteolysis in prokaryotic and eukaryotic cells.

Risk factors for suicide independent of DSM-III-R Axis I disorder. Case-control psychological autopsy study in Northern Ireland

BACKGROUND

The vast majority of suicides suffer from at least one mental disorder at the time of death.

AIMS

To identify risk factors for suicide, particularly those independent of current DSM-III-R Axis I disorder(s).

METHOD

A case-control psychological autopsy study comparing suicides with matched community controls.

RESULTS

Independent risk factors for suicide included: Axis II (personality) disorder (particularly antisocial, avoidant and dependent); at least one of 12 life events (from the List of Threatening Experiences) during the previous 52 or 4 weeks (in particular, a 'serious problem with close friend, neighbour or relative'); current unemployment; previous history of deliberate self-harm; and contact with a GP within 26 weeks. Relative to individuals with no current mental disorder, the estimated risk of suicide in those with Axis I-Axis II comorbidity (OR 346.0) was significantly greater than that in those with Axis I disorder(s) only (OR 52.4).

CONCLUSIONS

Suicide risk assessment may be enhanced by enquiry about the aforementioned independent risk factors, and attention to Axis I-Axis II comorbidity.

Characterization of the interaction between the Staphylococcus aureus clumping factor (ClfA) and fibrinogen

The ability of Staphylococcus aureus to adhere to adsorbed fibrinogen and fibrin is believed to be an important step in the initiation of biomaterial and wound-associated infections. In this study, we show that the binding site in fibrinogen for the recently identified S. aureus fibrinogen-binding protein clumping factor (ClfA) is within the C-terminus of the fibrinogen gamma chain. S. aureus Newman cells expressing ClfA adhered to microtitre wells coated with recombinant fibrinogen purified from BHK cells, but did not adhere to wells coated with a purified recombinant fibrinogen variant where the 4 C-terminal residues of the gamma chain were replaced by 20 unrelated residues. In addition, a synthetic peptide corresponding to the 17 C-terminal amino acids of the fibrinogen gamma chain effectively inhibited adherence of ClfA-expressing cells to fibrinogen. In western ligand blots, a recombinant truncated ClfA protein called Clf33 (residues 221-550) recognized intact recombinant fibrinogen gamma chains, but failed to recognize recombinant fibrinogen gamma chains where the 4 C-terminal amino acids were altered by deletion or substitution. Previous studies have shown that the C-terminal domain of fibrinogen gamma chains contains a binding site for the integrin alphaIIb beta3 (glycoprotein gpIIb/IIIa) receptor on platelets [Kloczewiak, M., Timmons, S., Bednarek, M. A., Sakon, M. & Hawiger, J. (1989) Biochemistry 28, 2915-1919; Farrell, D. H., Thiagarajan, P., Chung, D. W. & Davie, E. W. (1992) Proc. Natl. Acad. Sci. USA 89, 10729-10732; Hettasch, J. M., Bolyard, M. G. & Lord, S. T. (1992) Thromb. Haemostasis 68, 701-706]. We now show that Clf33 inhibits ADP-induced, fibrinogen-dependent platelet aggregation in a concentration-dependent manner and inhibits adhesion of platelets to immobilized fibrinogen under fluid shear stress, indicating that the binding sites for the platelet integrin and the staphylococcal adhesin overlap. The interaction between Clf33 and fibrinogen was further characterized using the BIAcore biosensor. When soluble Clf33 was allowed to bind to immobilized fibrinogen, a Kd of 0.51 +/- 0.19 microM was experimentally determined using equilibrium binding data. It was also shown that the synthetic C-terminal gamma-chain peptide effectively inhibited this interaction.

The psychological autopsy approach to studying suicide: a review of methodological issues

The psychological autopsy approach to studying suicide is becoming an increasingly used research method. It presents considerable methodological problems. In order to assist future researchers in this field and to help readers assess reports of psychological autopsy studies the authors have reviewed these issues on the basis of their own experience and those of other workers. The areas covered include research design, identification of subjects, sources of information and the particular issues concerned with approaching relatives and other informants, choice and recruitment of controls, the difficulties of conducting psychological autopsy interviews with relatives, problems for interviewers, the selection of appropriate measures to obtain information, and achieving valid and reasonably reliable conclusions from diverse information sources.

Teaching and assessing resident competence in practice-based learning and improvement

We designed, implemented, and evaluated a 4-week practice-based learning and improvement (PBLI) elective. Eleven internal medicine residents from 2 separate residency programs participated in the PBLI elective and 22 other residents comprised a comparison group. Residents in each group had similar pretest Quality Improvement Knowledge Application Tool scores; but after the PBLI elective, participant scores were significantly higher. Also, participants' self-assessed ratings of PBLI skills increased after the rotation and remained elevated 6 months afterward. In this curriculum, residents completed a project to improve patient care and demonstrated their knowledge on an evaluation tool in a way that was superior to nonparticipants.

Alpha-toxin and gamma-toxin jointly promote Staphylococcus aureus virulence in murine septic arthritis

Septic arthritis is a common and feared complication of staphylococcal infections. Staphylococcus aureus produces a number of potential virulence factors including certain adhesins and enterotoxins. In this study we have assessed the roles of cytolytic toxins in the development of septic arthritis by inoculating mice with S. aureus wild-type strain 8325-4 or isogenic mutants differing in the expression of alpha-, beta-, and gamma-toxin production patterns. Mice inoculated with either an alpha- or beta-toxin mutant showed degrees of inflammation, joint damage, and weight decrease similar to wild-type-inoculated mice. In contrast, mice inoculated with either double (alpha- and gamma-toxin-deficient)- or triple (alpha-, beta-, and gamma-toxin-deficient)-mutant S. aureus strains showed lower frequency and severity of arthritis, measured both clinically and histologically, than mice inoculated with the wild-type strain. We conclude that simultaneous production of alpha- and gamma-toxin is a virulence factor in S. aureus arthritis.

Patterns of use of antithrombotic therapy and quality of anticoagulation among patients with non-valvular atrial fibrillation in clinical practice

We conducted a retrospective cohort study of thromboprophylaxis rates and the quality of anticoagulation control among patients with atrial fibrillation (AF) using a large, geographically diverse database of electronic medical records. The study population consisted of 13,709 AF patients treated in US outpatient physician practices. Approximately two-thirds were prescribed warfarin alone or in combination with another drug. Older patients, males, and those with congestive heart failure (CHF) or prior stroke were more likely to receive antithrombotic therapy. Among 6454 patients treated with warfarin who had at least two valid prothrombin time/international normalised ratio test results, approximately half of study days were spent in target range. Female sex, CHF and residence in the Northeast were associated with more time out of range. Our study confirms that, in routine medical practice, warfarin is not prescribed for substantial numbers of eligible patients, and anticoagulation control with warfarin is suboptimal for many of those at risk for thromboembolism.

Coproducing Health Professions Education: A Prerequisite to Coproducing Health Care Services?

In 2016, Batalden et al proposed a coproduction model for health care services. Starting from the argument that health care services should demonstrate service-dominant rather than goods-dominant logic, they argued that health care outcomes are the result of the intricate interaction of the provider and patient in concert with the system, community, and, ultimately, society. The key notion is that the patient is as much an expert in determining outcomes as the provider, but with different expertise. Patients come to the table with expertise in their lived experiences and the context of their lives.The authors posit that education, like health care services, should follow a service-dominant logic. Like the relationship between patients and providers, the relationship between learner and teacher requires the integrated expertise of each nested in the context of their system, community, and society to optimize outcomes. The authors then argue that health professions learners cannot be educated in a traditional, paternalistic model of education and then expected to practice in a manner that prioritizes coproductive partnerships with colleagues, patients, and families. They stress the necessity of adapting the health care services coproduction model to health professions education. Instead of asking whether the coproduction model is possible in the current system, they argue that the current system is not sustainable and not producing the desired kind of clinicians.A current example from a longitudinal integrated clerkship highlights some possibilities with coproduced education. Finally, the authors offer some practical ways to begin changing from the traditional model. They thus provide a conceptual framework and ideas for practical implementation to move the educational model closer to the coproduction health care services model that many strive for and, through that alignment, to set the stage for improved health outcomes for all.

Selective killing of human monocytes and cytokine release provoked by sphingomyelinase (beta-toxin) of Staphylococcus aureus

The best-known activity of Staphylococcus aureus sphingomyelinase C, alias beta-toxin, is as a hemolysin that provokes hot-cold lysis of erythrocytes which contain substantial amounts of sphingomyelin in the plasma membrane. Sheep erythrocytes are most susceptible, and we found that one hemolytic unit, representing the toxin concentration that elicits 50% hemolysis of 2.5 X 10(8) erythrocytes per ml, corresponds to 0.05 enzyme units or to approximately 0.25 microg of sphingomyelinase per ml. The cytotoxic action of beta-toxin on nucleated cells has not been described in any detail before, and the present investigation was undertaken to fill this information gap. We now identify beta-toxin as a remarkably potent monocytocidal agent. At a concentration of 0.001 U/ml, corresponding to approximately 5 ng/ml, beta-toxin killed over 50% of human monocytes (10(6) cells per ml) within 60 min. By contrast, 1 to 5 microg of beta-toxin per ml had no cytocidal effects on human granulocytes, fibroblasts, lymphocytes, or erythrocytes. A selective monocytocidal action was also observed with sphingomyelinase C from Bacillus cereus and a Streptomyces sp., whereas phospholipase A2 and phospholipase D at 100 U/ml were without effect. Monocytes succumbing to the action of beta-toxin processed and released interleukin-1beta, soluble interleukin-6 receptor, and soluble CD14 into the supernatant. Thus, monocyte killing by beta-toxin is associated with cytokine-related events that are important for the initiation and progression of infectious disease. These findings uncover a potentially important role for sphingomyelinase as a determinant of microbial pathogenicity.

The impact of paediatric tracheostomy on both patient and parent

OBJECTIVE

We set out to assess the impact of paediatric tracheostomy, performed in a central London hospital, on patients and their families.

METHODS

We conducted structured interviews with caregivers of tracheostomised children using the Pediatric Tracheotomy Health Status Instrument during all in-patient admissions for airway endoscopy over a 6-month period.

RESULTS

Completed questionnaires were received from 26 caregivers, 7 (27%) of whose children had been successfully decannulated. Carers reported adverse effects on all aspects of their quality of life, including sleep, relationships, social life and ability to work. The families included in the study had gross household incomes below the mean for SE London. There is a shortfall in the provision of home nursing when compared with the needs of the caregivers.

CONCLUSIONS

Tracheostomy has wide ranging effects on the quality of life of both the patient and their caregivers. We identified the need for better pre-operative preparation where possible, and greater support for such families in the community.

Genetic variation in DNMT3B and increased global DNA methylation is associated with suicide attempts in psychiatric patients

Recently, a significant epigenetic component in the pathology of suicide has been realized. Here we investigate candidate functional SNPs in epigenetic-regulatory genes, DNMT1 and DNMT3B, for association with suicide attempt (SA) among patients with co-existing psychiatric illness. In addition, global DNA methylation levels [5-methyl cytosine (5-mC%)] between SA and psychiatric controls were quantified using the Methylflash Methylated DNA Quantification Kit. DNA was obtained from blood of 79 suicide attempters and 80 non-attempters, assessed for DSM-IV Axis I disorders. Functional SNPs were selected for each gene (DNMT1; n = 7, DNMT3B; n = 10), and genotyped. A SNP (rs2424932) residing in the 3' UTR of the DNMT3B gene was associated with SA compared with a non-attempter control group (P = 0.001; Chi-squared test, Bonferroni adjusted P value = 0.02). Moreover, haplotype analysis identified a DNMT3B haplotype which differed between cases and controls, however this association did not hold after Bonferroni correction (P = 0.01, Bonferroni adjusted P value = 0.56). Global methylation analysis showed that psychiatric patients with a history of SA had significantly higher levels of global DNA methylation compared with controls (P = 0.018, Student's t-test). In conclusion, this is the first report investigating polymorphisms in DNMT genes and global DNA methylation quantification in SA risk. Preliminary findings suggest that allelic variability in DNMT3B may be relevant to the underlying diathesis for suicidal acts and our findings support the hypothesis that aberrant DNA methylation profiles may contribute to the biology of suicidal acts. Thus, analysis of global DNA hypermethylation in blood may represent a biomarker for increased SA risk in psychiatric patients.

Role of Staphylococcus aureus surface-associated proteins in the attachment to cultured HaCaT keratinocytes in a new adhesion assay

Colonization of human skin with Staphylococcus aureus is a common feature in a variety of dermatologic diseases. In order to reproducibly investigate the adherence of Staphylococcus aureus to human epidermal cells, an in vitro assay was established using the biotin/streptavidine labeling system and the HaCaT cell line. This assay was used to define the role of several Staphylococcus aureus surface proteins with regard to their function in the staphylococcal adhesion process. Our studies included the standard laboratory strain Newman as well as its genetically constructed mutants DU5873, DU5852, DU5854, and DU5886 generated by allele replacement or transposon mutagenesis, which are deficient in the elaboration of staphylococcal protein A (spa), clumping factor (clfA), coagulase (coa), and the fibronectin-binding proteins A and B (fnbA/B), respectively. In comparison with strain Newman all mutants showed remarkably reduced adherence to the HaCaT keratinocyte cell line in our assay, yielding only between 43% and 60% of the adherence capacity of strain Newman after 60 min. Bacterial adherence could be re-established by introducing the cloned wild-type genes for the surface proteins on shuttle plasmids into the chromosomally defective mutants, thus suggesting a pathogenetic role of these proteins in the attachment of Staphylococcus aureus to human keratinocytes. Bacterial adherence was additionally enhanced by alkaline pH-values that are characteristic for skin conditions with epidermal barrier dysfunction. The use of Staphylococcus aureus mutant strains, deficient in the elaboration of defined proteins, allows specific investigation of colonization and virulence factors of this dermatologic relevant microorganism.

Safety of telephone consultation for "non-serious" emergency ambulance service patients

OBJECTIVE

To assess the safety of nurses and paramedics offering telephone assessment, triage, and advice as an alternative to immediate ambulance dispatch for emergency ambulance service callers classified by lay call takers as presenting with "non-serious" problems (category C calls).

DESIGN

Data for this study were collected as part of a pragmatic randomised controlled trial reported elsewhere. The intervention arm of the trial comprised nurse or paramedic telephone consultation using a computerised decision support system to assess, triage, and advise patients whose calls to the emergency ambulance service had been classified as "non-serious" by call takers applying standard priority dispatch criteria. A multidisciplinary expert clinical panel reviewed data from ambulance service, accident and emergency department, hospital inpatient and general practice records, and call transcripts for patients triaged by nurses and paramedics into categories that indicated that dispatch of an emergency ambulance was unnecessary. All cases for which one or more members of the panel rated that an emergency ambulance should have been dispatched were re-reviewed by the entire panel for an assessment of the "life risk" that might have resulted.

SETTING

Ambulance services in London and the West Midlands, UK.

STUDY POPULATION

Of 635 category C patients assessed by nurses and paramedics, 330 (52%) cases that had been triaged as not requiring an emergency ambulance were identified.

MAIN OUTCOME MEASURES

Assessment of safety of triage decisions.

RESULTS

Sufficient data were available from the routine clinical records of 239 (72%) subjects to allow review by the specialist panel. For 231 (96.7%) sets of case notes reviewed, the majority of the panel concurred with the nurses' or paramedics' triage decision. Following secondary review of the records of the remaining eight patients, only two were rated by the majority as having required an emergency ambulance within 14 minutes. For neither of these did a majority of the panel consider that the patient would have been at "life risk" without an emergency ambulance being immediately dispatched. However, the transcripts of these two calls indicated that the correct triage decision had been communicated to the patient, which suggests that the triage decision had been incorrectly entered into the decision support system.

CONCLUSIONS

Telephone advice may be a safe method of managing many category C callers to 999 ambulance services. A clinical trial of the full implementation of this intervention is needed, large enough to exclude the possibility of rare adverse events.

Computer assisted assessment and advice for "non-serious" 999 ambulance service callers: the potential impact on ambulance despatch

OBJECTIVE

To investigate the potential impact for ambulance services of telephone assessment and triage for callers who present with non-serious problems (Category C calls) as classified by ambulance service call takers.

DESIGN

Pragmatic controlled trial. Calls identified using priority dispatch protocols as non-serious were allocated to intervention and control groups according to time of call. Ambulance dispatch occurred according to existing procedures. During intervention sessions, nurses or paramedics within the control room used a computerised decision support system to provide telephone assessment, triage and, if appropriate, offer advice to permit estimation of the potential impact on ambulance dispatch.

SETTING

Ambulance services in London and the West Midlands.

SUBJECTS

Patients for whom emergency calls were made to the ambulance services between April 1998 and May 1999 during four hour sessions sampled across all days of the week between 0700 and 2300.

MAIN OUTCOME MEASURES

Triage decision, ambulance cancellation, attendance at an emergency department.

RESULTS

In total, there were 635 intervention calls and 611 controls. Of those in the intervention group, 330 (52.0%) were triaged as not requiring an emergency ambulance, and 119 (36.6%) of these did not attend an emergency department. This compares with 55 (18.1%) of those triaged by a nurse or paramedic as requiring an ambulance (odds ratio 2.62; 95% CI 1.78 to 3.85). Patients triaged as not requiring an emergency ambulance were less likely to be admitted to an inpatient bed (odds ratio 0.55; 95% CI 0.33 to 0.93), but even so 30 (9.2%) were admitted. Nurses were more likely than paramedics to triage calls into the groups classified as not requiring an ambulance. After controlling for age, case mix, time of day, day of week, season, and ambulance service, the results of a logistic regression analysis revealed that this difference was significant with an odds ratio for nurses:paramedics of 1.28 (95% CI 1.12 to 1.47).

CONCLUSIONS

The findings indicate that telephone assessment of Category C calls identifies patients who are less likely to require emergency department care and that this could have a significant impact on emergency ambulance dispatch rates. Nurses were more likely than paramedics to assess calls as requiring an alternative response to emergency ambulance despatch, but the extent to which this relates to aspects of training and professional perspective is unclear. However, consideration should be given to the acceptability, reliability, and cost consequences of this intervention before it can be recommended for full evaluation.

Temporomandibular joint: magnetic resonance imaging

Magnetic resonance (MR) imaging of the temporomandibular joint was performed in two subjects using a 1.5 T experimental imaging system equipped with a 6.5 cm surface coil antenna. Normal and pathologic anatomy were demonstrated with exquisite detail. Anterior displacement of the joint meniscus was clearly visible in the symptomatic subject, consistent with arthrographic confirmation.

Cloning, expression, and mapping of the Staphylococcus aureus alpha-hemolysin determinant in Escherichia coli K-12

A fragment of Staphylococcus aureus DNA encoding the alpha-hemolysin determinant was cloned from strain Wood 46 by inserting Sau3A-generated genomic DNA fragments between the BamHI sites of the lambda replacement vector L47.1. Phages expressing alpha-hemolysin were detected by overlaying plaques formed from several thousand independent recombinant phage with erythrocytes and looking for zones of hemolysis. One phage expressing alpha-hemolysin was purified and named lambda w alpha 3. This was subsequently shown to contain a 10.2-kilobase pair insert of S. aureus DNA. A 7.6-kilobase pair HindIII fragment encoding the alpha-hemolysin was subcloned from lambda w alpha 3 into the plasmid vector pACYC184 to form the hybrid plasmid pDU1148. Escherichia coli K-12 cells harboring pDU1148 synthesized a low level of alpha-hemolysin which remained associated with the cells and was not secreted into culture supernatants. When the same strain was stabbed onto blood agar plates, no zones of hemolysis were detected after overnight growth at 37 degrees C but hemolysis developed if the plates were left at room temperature for 48 h. By introducing specific deletions or Tn5 insertions into plasmid pDU1148, the alpha-hemolysin gene was mapped to a region within a 3.3-kilobase pair EcoRI-HindIII fragment which was subcloned onto the vector plasmid pBR322. A specific enzyme-linked immunosorbent assay with peroxidase-labeled rabbit anti-alpha-hemolysin antibodies was used to measure the levels of alpha-hemolysin antigen expressed in E. coli K-12 cells harboring pDU1148 or a variety of pDU1148::Tn5 and pDU1148 deletion mutants.

Homeobox genes in the functioning of plant meristems

The maize homebox gene knotted1 (kn1) is expressed in vegetative and floral meristems and is down-regulated at the site of primordia formation. kn1-related genes from maize and other species also show meristem-specific expression and offer additional tools for studying the activities of shoot meristems. Members of this gene family are expressed early in embryogenesis, providing molecular markers for meristem initiation. Ectopic expression of either kn1 or a related Arabidopsis gene, KNAT1, causes dramatic alterations in Arabidopsis and tobacco leaf morphology. Most significantly, meristems form on the leaf, producing small shoots. We discuss whether the phenotypes can be interpreted as changes in positional information or timing of determination.

Role of Staphylococcus aureus surface adhesins in orthopaedic device infections: are results model-dependent?

Bacterial colonisation of prosthetic material can lead to clinical infection or implant failure, or both, often requiring removal of the device. Adherence of Staphylococcus aureus to bioprosthetic materials is mediated by adhesins belonging to the MSCRAMM (microbial surface components recognising adhesive matrix molecules) family of microbial cell surface proteins. The objective of this study was to compare the virulence of a mutant strain of S. aureus Newman that possesses all three fibrinogen-, fibronectin- and collagen-binding MSCRAMMs (MSCRAMM-positive strain) with that of a mutant strain that lacks all three types of MSCRAMMs (MSCRAMM-negative strain) in a rabbit model of orthopaedic device-related infection. After a hole was drilled into the knee joint of each animal, a group of 10 rabbits was inoculated with the MSCRAMM-positive strain and another group of 10 rabbits received the MSCRAMM-negative strain. A stainless steel screw was then placed into the drilled hole. Two weeks later, the rabbits were killed and serum samples, bone tissue and implants were harvested for bacteriological and histopathological evaluation. No significant difference in infection rates was demonstrated between the two groups. The ability to delineate the role of S. aureus surface adhesins in causing orthopaedic device-related infection could be model-dependent.

Phase I study of temozolamide (TMZ) combined with procarbazine (PCB) in patients with gliomas

Temozolomide (TMZ) is an oral alkylating agent with a good safety profile and proven efficacy in the treatment of malignant glioma. Procarbazine (PCB) has been used for treating gliomas for many years and here both agents were combined in the treatment. This phase I study was designed to evaluate the efficacy and safety of TMZ alone (course 1) and TMZ in combination with PCB in subsequent courses in chemotherapy-naïve patients with malignant glioma. Patients with anaplastic astrocytoma (AA), glioblastoma multiforme (GBM) and low-grade glioma were treated with TMZ 200 mg m(-2) on days 1-5 on a 28-day cycle for course 1. Beginning with course 2, cohorts of patients received TMZ at full dose with escalating doses of PCB (50/75/100/125 mg m(-2) days 1-5 given 1 h prior to TMZ). A total of 28 patients were enrolled with three patients each at dose level 1 and 2, 16 patients at dose level 3 and six patients at dose level 4 received 182+ cycles of treatment and were included in this analysis. In all, 16 patients had GBM, seven patients had AA, five had grade 1 or 2 glioma and the median age was 47 years. The patients had received prior surgery and radiotherapy. Responses were seen at all dose levels. Overall, there were 10 (36%) responses lasting from 2 to 17+ months. Treatment was generally well tolerated with few grade 3 or 4 toxicities, except at dose level 4, where four patients had grade 3/4 had thrombocytopaenia at this dose and several patients had moderate-to-severe lethargy. TMZ 200 mg m(-2) and PCB 100 mg m(-2) were well tolerated on a daily 5 x and four weekly cycle in patients with malignant glioma and clearly had antitumour activity.