Dorsal closure is an essential stage of Drosophila development that is a model system for research in morphogenesis and biological physics. Dorsal closure involves an orchestrated interplay between gene expression and cell activities that produce shape changes, exert forces and mediate tissue dynamics. We investigate the dynamics of dorsal closure based on confocal microscopic measurements of cell shortening in living embryos. During the mid-stages of dorsal closure we find that there are fluctuations in the width of the leading edge cells but the time-averaged analysis of measurements indicate that there is essentially no net shortening of cells in the bulk of the leading edge, that contraction predominantly occurs at the canthi as part of the process for zipping together the two leading edges of epidermis and that the rate constant for zipping correlates with the rate of movement of the leading edges. We characterize emergent properties that regulate dorsal closure, i.e., a velocity governor and the coordination and synchronization of tissue dynamics.
Two new species of the genus Myrmarachne are described (Myrmarachne acutidens
sp. n., Myrmarachne epigealis
sp. n.), and Myrmarachne macrognatha and Myrmarachne melanocephala are redescribed from Flores specimens. The females of Myrmarachne macrognatha are recorded for the first time.
New species; ant-mimicking jumping spiders; Java; Malay Archipelago
This study explored strain distribution and resistance patterns of methicillin-resistant Staphylococcus aureus (MRSA) over a 5-year period in northeastern Scotland. We noted a shift in the relative rates of epidemic strains and an increase in community-associated strains. Use of oral antibiotics to eradicate throat carriage may have contributed to trimethoprim resistance, which was observed to increase 10-fold.
This study was conducted to assess the occurrence of fractures in solid-organ transplant recipients. Methods. Medical record review and surveys were performed. Patients received less than 6 months of glucocorticoids. Results. Of 351 transplant patients, 175 patients provided fracture information, with 48 (27.4%) having fractured since transplant (2–6 years). Transplants included 19 kidney/liver (50% male), 47 kidney/pancreas (53% male), 92 liver (65% male), and 17 pancreas transplants (41% male). Age at transplant was 50.8 ± 10.3 years. Fractures were equally seen across both genders and transplant types. Calcium supplementation (n = 94) and bisphosphonate therapy (n = 52) were observed, and an association with a lower risk of fractures was noted for bisphosphonate users (OR = 0.45 95% C.I. 0.24, 0.85). Fracture location included 8 (16.7%) foot, 12 (25.0%) vertebral, 3 (6.3%) hand, 2 (4.2%) humerus, 5 (10.4%) wrist, 10 (20.8%) fractures at other sites, and 7 (14.6%) multiple fractures. The estimated relative risk of fracture was nearly seventeen-times higher in male liver transplant recipients ages 45–64 years compared with the general male population, and comparable to fracture rates on conventional immunosuppressant regimens. Conclusion. We identify a high frequency of fractures in transplant recipients despite limited glucocorticoid use.
In the United Kingdom, EMRSA-15 and EMRSA-16 account for the majority (∼90%) of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infections. Currently, the standard typing technique, pulsed-field gel electrophoresis (PFGE), is laborious and insufficient for discriminating between closely related subtypes of EMRSA-15 and -16. The objective of the present study was to compare the usefulness of multilocus variable-number tandem-repeat fingerprinting (MLVF) and multilocus variable-number tandem-repeat analysis (MLVA) with PFGE for subtyping these highly clonal MRSA lineages. A panel of 85 MRSA isolates (41 EMRSA-15, 20 EMRSA-16, and 24 MRSA isolates with diverse PFGE patterns) was investigated. In addition, a further 29 EMRSA-15s with identical PFGE patterns from two geographically linked but epidemiologically distinct outbreaks and several sporadic cases were analyzed. PFGE, MLVF, and MLVA resolved 66 (Simpson's index of diversity [SID] = 0.984), 51 (SID = 0.95), and 42 (SID = 0.881) types, respectively, among the 85 MRSA isolates. MLVF was more discriminatory than MLVA for EMRSA-15 and -16 strains, but both methods had comparable discriminatory powers for distinguishing isolates in the group containing diverse PFGE types. MLVF was comparable to PFGE for resolving the EMRSA-15s but had a lower discriminatory power for the EMRSA-16s. MLVF and MLVA resolved the 29 isolates with identical PFGE patterns into seven and six subtypes, respectively. Importantly, both assays indicated that the two geographically related outbreaks were caused by distinct subtypes of EMRSA-15. Taken together, the data suggest that both methods are suitable for identifying and tracking specific subtypes of otherwise-indistinguishable MRSA. However, due to its greater discriminatory power, MLVF would be the most suitable alternative to PFGE for hospital outbreak investigations.
Several studies have described improved outcomes for HIV‐infected patients admitted to the intensive care unit (ICU) since the introduction of highly active antiretroviral therapy (HAART). A study was undertaken to examine the outcome from the ICU for HIV‐infected patients and to identify prognostic factors.
A retrospective study of HIV‐infected adults admitted to a university affiliated hospital ICU between January 1999 and December 2005 was performed. Information was collected on patient demographics, receipt of HAART (no patient began HAART on the ICU), reason for ICU admission and hospital course. Outcomes were survival to ICU discharge and to hospital discharge.
102 patients had 113 admissions to the ICU; HIV infection was newly diagnosed in 31 patients. Survival (first episode ICU discharge and hospital discharge) was 77% and 68%, respectively, compared with 74% and 65% for general medical patients. ICU and hospital survival was 78% and 67% in those receiving HAART, and 75% and 66% in those who were not. In univariate analysis, factors associated with survival were: haemoglobin (OR = 1.25, 95% CI 1.03 to 1.51, for an increase of 1 g/dl), CD4 count (OR = 1.59, 95% CI 0.98 to 2.58, for a 10‐fold increase in cells/µl), APACHE II score (OR = 0.51, 95% CI 0.29 to 0.90, for a 10 unit increase) and mechanical ventilation (OR = 0.29, 95% CI 0.10 to 0.83).
The outcome for HIV‐infected patients admitted to the ICU was good and was comparable to that in general medical patients. More than a quarter of patients had newly diagnosed HIV infection. Patients receiving HAART did not have a better outcome.
In September 2006, the seven-valent pneumococcal conjugate vaccine (PCV7; Prevenar) was introduced into the childhood vaccination schedule in the United Kingdom. We monitored the population of invasive pneumococci in Scotland in the 5 years preceding the introduction of PCV7 by using serogrouping, multilocus sequence typing (MLST), and eBURST analysis. Here, we present a unique analysis of a complete national data set of invasive pneumococci over this time. We observed an increase in invasive pneumococcal disease (IPD) caused by serotypes 1, 4, and 6 and a decrease in serogroup 14-, 19-, and 23-associated disease. Analysis of sequence type (ST) data shows a significant increase in ST306, associated with serotype 1, and a decrease in ST124, associated with serotype 14. There have also been increases in the amounts of IPD caused by ST227 (serotype 1) and ST53 (serotype 8), although these increases were not found to reach significance (P = 0.08 and 0.06, respectively). In the course of the study period preceding the introduction of PCV7, we observed considerable and significant changes in serogroup and clonal distribution over time.
To explore the associations between self reported high risk sexual behaviours and subsequent diagnosis with hepatitis C virus (HCV) infection.
The Sex, Health and Anti‐Retrovirals Project (SHARP) was a cross sectional study of sexual behaviour in HIV positive, men who have sex with men (MSM) attending a London outpatient clinic. From July 1999 to August 2000 participants completed a computer assisted self interview questionnaire (CASI) on recent sexual behaviour, recreational drug use, and detailed reporting of the last two sexual episodes involving different partners. Results were combined with routine clinic data and subsequent testing for HCV up to 21 April 2005. A new HCV diagnosis was defined as anti‐HCV antibody seroconversion or positive HCV RNA following a previous negative. Incident rate ratios (IRR) were calculated using Poisson regression in Stata (version 9). Men contributed time at risk from interview until either their diagnosis or their last negative test result.
Of the 422 men who completed questionnaires, 308 (73%) had sufficient clinical and HCV testing data available for analysis. Incident HCV infection was identified in 11 men. Unprotected anal intercourse, more than 30 sex partners in the past year, higher numbers of new anal sex partners, rimming (oro‐anal sex), fisting, use of sex toys, and intranasal recreational drug use were associated with HCV. In multivariate analysis only fisting remained associated with HCV (adjusted IRR 6.27, p = 0.005).
In this study of HIV positive MSM, fisting is strongly associated with HCV infection. Where individuals report high risk sexual behaviours, clinicians should offer appropriate testing for HCV infection.
hepatitis C virus infection; sexual behaviour; MSM; HIV positive
Despite a decline in incidence of Pneumocystis jirovecii pneumonia (PCP), severe PCP continues to be a common cause of admission to the intensive care unit (ICU) where mortality remains high. A study was undertaken to examine the outcome from intensive care for patients with PCP and to identify prognostic factors.
A retrospective cohort study was conducted of HIV infected adults admitted to a university affiliated hospital ICU between November 1990 and October 2005. Case note review collected information on demographic variables, use of prophylaxis and highly active antiretroviral therapy (HAART), and hospital course. The main outcome was 1 month mortality, either on the ICU or in hospital.
Fifty nine patients were admitted to the ICU on 60 occasions. Thirty four patients (57%) required mechanical ventilation. Overall mortality was 53%. No patient received HAART before or during ICU admission. Multivariate analysis showed that the factors associated with mortality were the year of diagnosis (before mid 1996 (mortality 71%) compared with later (mortality 34%; p = 0.008)), age (p = 0.016), and the need for mechanical ventilation and/or development of pneumothorax (p = 0.031). Mortality was not associated with sex, ethnicity, prior receipt of sulpha prophylaxis, haemoglobin, serum albumin, CD4 count, Pao2, A‐ao2 gradient, co‐pathology in bronchoscopic lavage fluid, medical co‐morbidity, APACHE II score, or duration of mechanical ventilation.
Observed improved outcomes from severe PCP for patients admitted to the ICU occurred in the absence of intervention with HAART and probably reflect general improvements in ICU management of respiratory failure and ARDS rather than improvements in the management of PCP.
AIDS; intensive care; mechanical ventilation;
; opportunistic infections; respiratory failure
bystander effect; fluorescence redistribution; gap junction; ultrasoft X-rays
Aims: To describe the laboratory confirmation of meningococcal disease, using culture and non-culture based techniques, between 1993 and 1999 as part of a national service in Scotland.
Methods: Samples from patients with suspected meningococcal disease in Scotland were analysed by culture and non-culture based techniques to gain a laboratory confirmation of disease. Data were analysed to establish the number of disease cases, the serogroups of the organisms involved, and the importance of the techniques used.
Results: Between 1993 and 1999, there was a total of 1749 notified cases of meningococcal disease in Scotland. Culture based methods provided a laboratory confirmation of 788 cases whereas non-culture techniques confirmed 461 cases.
Conclusions: Non-culture techniques were a useful addition to culture based techniques in Scotland and improved the dataset required for public health management, disease surveillance, and vaccine policy.
meningococcal disease; Neisseria meningitidis; non-culture diagnosis
The Scottish Meningococcus and Pneumococcus Reference Laboratory provides a national service for the laboratory confirmation of meningococcal and pneumococcal disease in Scotland. The main tests used for the laboratory confirmation of meningococcal disease are culture, the polymerase chain reaction (PCR), antibody testing, and more recently DNA sequencing. This paper describes the automation of PCR for the laboratory confirmation of meningococcal disease and the typing of meningococcal isolates using DNA sequencing. Both methods have been automated using a robotic liquid handler and automated DNA sequencer. These methods, along with standard culture phenotyping and antibody testing, provide Scotland with an excellent service for the confirmation of meningococcal disease.
Key Words: automation • Neisseria meningitidis • meningococci • meningitis
A fluoresence-based PCR method was developed, fully automated, and used to confirm infection with Neisseria meningitidis by detection of the meningococcus-specific ctrA gene. The method provided a highly sensitive, high-throughput assay that was reproducible and less labor-intensive than manual methods.
The Scottish Meningococcus and Pneumococcus Reference Laboratory (SMPRL) provides a national service for the laboratory confirmation of meningococcal and pneumococcal disease in Scotland. Part of this service includes the serogrouping of meningococcal isolates followed by typing and subtyping. The procedures for this are labor-intensive but important for the identification of linked cases and the surveillance of disease so that effective public health measures can be taken. However, different strains of meningococci, such as those within the electrophoretic type 37 complex, occurring during case clusters of disease are now indistinguishable by current methods. The SMPRL has started using multilocus sequence typing (MLST) as a routine method for the characterization of isolates of Neisseria meningitidis. MLST produces nucleotide sequence data of seven housekeeping genes providing results that are useful for public health management. However, the method is laborious and time-consuming and therefore lends itself towards automation. The SMPRL therefore developed a semiautomated method for MLST using a 96-well format liquid handler and an automated DNA sequencer. Semiautomated MLST is now provided as a reference service for Scotland. This work describes the methodology required for the characterization of N. meningitidis and highlights its usefulness for public health intervention.
We developed a PCR-based assay to quantify trichothecene-producing Fusarium based on primers derived from the trichodiene synthase gene (Tri5). The primers were tested against a range of fusarium head blight (FHB) (also known as scab) pathogens and found to amplify specifically a 260-bp product from 25 isolates belonging to six trichothecene-producing Fusarium species. Amounts of the trichothecene-producing Fusarium and the trichothecene mycotoxin deoxynivalenol (DON) in harvested grain from a field trial designed to test the efficacies of the fungicides metconazole, azoxystrobin, and tebuconazole to control FHB were quantified. No correlation was found between FHB severity and DON in harvested grain, but a good correlation existed between the amount of trichothecene-producing Fusarium and DON present within grain. Azoxystrobin did not affect levels of trichothecene-producing Fusarium compared with those of untreated controls. Metconazole and tebuconazole significantly reduced the amount of trichothecene-producing Fusarium in harvested grain. We hypothesize that the fungicides affected the relationship between FHB severity and the amount of DON in harvested grain by altering the proportion of trichothecene-producing Fusarium within the FHB disease complex and not by altering the rate of DON production. The Tri5 quantitative PCR assay will aid research directed towards reducing amounts of trichothecene mycotoxins in food and animal feed.
A proportion of patients with AIDS and toxoplasmic encephalitis (TE) sustain low plasma pyrimethamine concentrations during oral treatment, possibly because of incomplete and variable bioavailability. We wanted to develop a safe, practicable intravenous (i.v.) formulation of pyrimethamine and characterize its disposition in healthy volunteers. A neutral, aqueous, sterile solution of pyrimethamine was produced and presented in sealed glass ampoules. Pyrimethamine (1 mg/kg) was given to eight healthy male volunteers by i.v. infusion over 2 h, and blood was sampled over a 2 week period. Pyrimethamine levels in plasma were measured by high-performance liquid chromatography. The drug was well tolerated by all volunteers, and there were no changes in vital signs, electrocardiogram, hematology, or biochemical parameters. The maximum pyrimethamine concentration of 2,089 ± 565 ng ml−1 (mean ± standard deviation) was achieved shortly after the end of the infusion; thereafter, concentrations declined in a log-linear manner, with a half-life of 140 ± 31 h.
The ultimate goal of machine vision is image understanding-the ability not only to recover image structure but also to know what it represents. By definition, this involves the use of models which describe and label the expected structure of the world. Over the past decade, model-based vision has been applied successfully to images of man-made objects. It has proved much more difficult to develop model-based approaches to the interpretation of images of complex and variable structures such as faces or the internal organs of the human body (as visualized in medical images). In such cases it has been problematic even to recover image structure reliably, without a model to organize the often noisy and incomplete image evidence. The key problem is that of variability. To be useful, a model needs to be specific-that is, to be capable of representing only 'legal' examples of the modelled object(s). It has proved difficult to achieve this whilst allowing for natural variability. Recent developments have overcome this problem; it has been shown that specific patterns of variability in shape and grey-level appearance can be captured by statistical models that can be used directly in image interpretation. The details of the approach are outlined and practical examples from medical image interpretation and face recognition are used to illustrate how previously intractable problems can now be tackled successfully. It is also interesting to ask whether these results provide any possible insights into natural vision; for example, we show that the apparent changes in shape which result from viewing three-dimensional objects from different viewpoints can be modelled quite well in two dimensions; this may lend some support to the 'characteristic views' model of natural vision.
Evidence-based medicine (EBM) aids clinical decision making in all fields of medicine, including primary care. General practice is characterized by particular emphasis on the doctor-patient relationship and on biomedical, personal and contextual perspectives in diagnosis. Most evidence available to general practitioners (GPs) addresses only the bio-medical perspective and is often not directly applicable to primary care, as it derives from secondary or tertiary care. Emphasis on the biomedical domain and the randomized controlled trial (RCT) alone reflects a reductionist approach that fails to do justice to the philosophy of general practice. The art of medicine is founded on context, anecdote, patient stories of illness and personal experience, and we should continue to blend this with good quality and appropriate research findings in patient care.
We have used molecular techniques to characterize 51 group A streptococci from Scotland and 17 'serious disease' isolates from other countries, in order to establish the clonal structure of invasive Streptococcus pyogenes strains circulating between 1986 and 1993. Strains were grouped by restriction endonuclease analysis, pulsed field gel electrophoresis and ribotyping patterns, and were examined for the presence of alleles of the speA gene by polymerase chain reaction and DNA sequence analysis. Serious and fatal infections in Scotland were caused by several clones. One clone (9 of 51 strains) was M type 1 and possessed the speA gene allele 2. This was the clone previously identified as causing severe infection in the USA. Another clone (5 of 51 strains) was M type 3 and had speA gene allele 3. In view of the clear association of more than one clone with severe, invasive and fatal infections, horizontal gene exchange between genotypes merits further investigation.