Picoflare jets power the solar wind emerging from a coronal hole on the Sun

Coronal holes are areas on the Sun with open magnetic field lines. They are a source region of the solar wind, but how the wind emerges from coronal holes is not known. We observed a coronal hole using the Extreme Ultraviolet Imager on the Solar Orbiter spacecraft. We identified jets on scales of a few hundred kilometers, which last 20 to 100 seconds and reach speeds of ~100 kilometers per second. The jets are powered by magnetic reconnection and have kinetic energy in the picoflare range. They are intermittent but widespread within the observed coronal hole. We suggest that such picoflare jets could produce enough high-temperature plasma to sustain the solar wind and that the wind emerges from coronal holes as a highly intermittent outflow at small scales.

Ultra-high-resolution observations of persistent null-point reconnection in the solar corona

Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s^-1 and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona.

Microvascular Endothelial Function and Neurocognition Among Adults With Major Depressive Disorder

BACKGROUND

Cardiovascular risk factors (CVRFs) and endothelial dysfunction have been associated independently with poorer neurocognition in middle-aged adults, particularly on tests of frontal lobe function. However, to our knowledge, no studies have examined markers of microvascular dysfunction on neurocognition or the potential interaction between macro- and microvascular biomarkers on neurocognition in middle-aged and older adults with major depressive disorder (MDD).

METHODS

Participants included 202 adults with MDD who were not receiving mental health treatment. Microvascular endothelial function was assessed using a noninvasive marker of forearm reactive hyperemia velocity while macrovascular endothelial function was assessed using flow-mediated dilation (FMD) of the brachial artery. CVRFs were assessed using the Framingham Stroke Risk Profile and fasting lipid levels. A standardized neurocognitive assessment battery was used to assess three cognitive domains: executive function, working memory, and verbal memory.

RESULTS

Greater microvascular dysfunction was associated with poorer neurocognition across all three domains. Microvascular function continued to predict verbal memory performance after accounting for background factors and CVRFs. Macro- and microvascular function interacted to predict working memory performance (F = 4.51_{1, 178}, p = 0.035), with a similar nonsignificant association for executive function (F = 2.73_{1, 178}, p = 0.095), with moderate associations observed between microvascular function and neurocognition in the presence of preserved FMD (r₆₁ = 0.40, p = 0.001), but not when FMD was impaired (r₆₃ = -0.05, p = 0.675).

CONCLUSION

Greater microvascular dysfunction is associated with poorer neurocognition among middle-aged and older adults. This association was strongest in participants with preserved macrovascular function.

Postoperative cognitive dysfunction and mortality following lung transplantation

Preliminary evidence suggests that postoperative cognitive dysfunction (POCD) is common after lung transplantation. The impact of POCD on clinical outcomes has yet to be studied. The association between POCD and longer-term survival was therefore examined in a pilot study of posttransplantation survivors. Forty-nine participants from a prior randomized clinical trial underwent a neurocognitive assessment battery pretransplantation and 6 months posttransplantation, including assessments of the domains of Executive Function (Trail Making Test, Stroop, Digit Span), Processing Speed (Ruff 2 and 7 Test, Digit Symbol Substitution Test), and Verbal Memory (Verbal Paired Associates, Logical Memory, Animal Naming, and Controlled Oral Word Association Test). During a 13-year follow-up, 33 (67%) participants died. Greater neurocognition was associated with longer survival (hazard ratio [HR] = 0.49 [0.25-0.96], P = .039), and this association was strongest on tests assessing Processing Speed (HR = 0.58 [0.36-0.95], P = .03) and Executive Function (HR = 0.52 [0.28-0.97], P = .040). In addition, unadjusted analyses suggested an association between greater Memory performance and lower risk of CLAD (HR = 0.54 [0.29-1.00], P = .050). Declines in Executive Function tended to be predictive of worse survival. These preliminary findings suggest that postoperative neurocognition is predictive of subsequent mortality among lung transplant recipients. Further research is needed to confirm these findings in a larger sample and to examine mechanisms responsible for this relationship.

Histological and Environmental Changes in Longstanding Ileal Conduits

Seventeen patients with urinary diversions present for between 10 and 17 years were examined endoscopically. The region of the anastomosis was successfully biopsied in 13 cases. Biopsy specimens were examined both histologically and cytologically. Urine was aspirated from the conduits under sterile conditions and sent for qualification of bacterial flora. Histology revealed a variable degree of villous atrophy, mucosal metaplasia, crypt hyperplasia and in one case, antral type gland metaplasia. The finding of hyperplasia was corroborated by flow cytometry which demonstrated a high percentage of cells in G2 and metaphase. The majority of cases showed a colonic type of bacterial colonization and mucin histochemistry demonstrated a colonic type of mucin.

Retroperitoneal Fibrosis Complicating Intravesical Formalin Therapy

Two cases are reported of ureteric obstruction due to retroperitoneal fibrosis following the use of intravesical formalin. This particular complication of this treatment has not previously been described.

Non-Vascularized Free Toe Phalanx Transfers in Congenital Hand Deformities – the Great Ormond Street Experience

Many options of varying complexity are available for the management of congenital short digits resulting from aphalangia in symbrachydactyly and constriction ring syndrome. We have used non-vascularized free toe phalanx transfers for these children when a vascularized toe transfer has been contraindicated. We describe our technique and experience with 22 children who underwent a total of 64 transfers of the proximal (35) or middle (29) toe phalanges (average 3 per child). The mean age at initial surgery was 15 months, and the mean follow-up was 5 years. Duration of time until epiphyseal closure could not be determined accurately, but total digital elongation averaged 6 mm. Complications of this technique include joint instability, premature epiphyseal closure and, in one patient, infection and graft loss. Donor site deformity was determined according to measured growth deficit and toe function. This technique is a simple option for digital elongation and, if performed in the appropriate age group in short fingered and monodactylous subtypes of symbrachydactyly, has the potential to allow growth and function with minimal donor site deficit.

Dynamically controlled deposition of colloidal nanoparticle suspension in evaporating drops using laser radiation

Dynamic control of the distribution of polystyrene suspended nanoparticles in evaporating droplets is investigated using a 2.9 μm high power laser. Under laser radiation a droplet is locally heated and fluid flows are induced that overcome the capillary flow, and thus a reversal of the coffee-stain effect is observed. Suspension particles are accumulated in a localised area, one order of magnitude smaller than the original droplet size. By scanning the laser beam over the droplet, particles can be deposited in an arbitrary pattern. This finding raises the possibility for direct laser writing of suspended particles through a liquid layer. Furthermore, a highly uniform coating is possible by manipulating the laser beam diameter and exposure time. The effect is expected to be universally applicable to aqueous solutions independent of solutes (either particles or molecules) and deposited substrates.

The interaction between artemether-lumefantrine and lopinavir/ritonavir-based antiretroviral therapy in HIV-1 infected patients

Background

Artemether-lumefantrine is currently the most widely recommended treatment of uncomplicated malaria. Lopinavir–based antiretroviral therapy is the commonly recommended second-line HIV treatment. Artemether and lumefantrine are metabolised by cytochrome P450 isoenzyme CYP3A4, which lopinavir/ritonavir inhibits, potentially causing clinically important drug-drug interactions.

Methods

An adaptive, parallel-design safety and pharmacokinetic study was conducted in HIV-infected (malaria-negative) patients: antiretroviral-naïve and those stable on lopinavir/ritonavir-based antiretrovirals. Both groups received the recommended six-dose artemether-lumefantrine treatment. The primary outcome was day-7 lumefantrine concentrations, as these correlate with antimalarial efficacy. Adverse events were solicited throughout the study, recording the onset, duration, severity, and relationship to artemether-lumefantrine.

Results

We enrolled 34 patients. Median day-7 lumefantrine concentrations were almost 10-fold higher in the lopinavir than the antiretroviral-naïve group [3170 versus 336 ng/mL; p = 0.0001], with AUC_(0-inf) and C_max increased five-fold [2478 versus 445 μg.h/mL; p = 0.0001], and three-fold [28.2 versus 8.8 μg/mL; p < 0.0001], respectively. Lumefantrine C_max, and AUC_(0-inf) increased significantly with mg/kg dose in the lopinavir, but not the antiretroviral-naïve group. While artemether exposure was similar between groups, C_max and AUC_(0-8h) of its active metabolite dihydroartemisinin were initially two-fold higher in the lopinavir group [p = 0.004 and p = 0.0013, respectively]. However, this difference was no longer apparent after the last artemether-lumefantrine dose. Within 21 days of starting artemether-lumefantrine there were similar numbers of treatment emergent adverse events (42 vs. 35) and adverse reactions (12 vs. 15, p = 0.21) in the lopinavir and antiretroviral-naïve groups, respectively. There were no serious adverse events and no difference in electrocardiographic QTcF- and PR-intervals, at the predicted lumefantrine T_max.

Conclusion

Despite substantially higher lumefantrine exposure, intensive monitoring in our relatively small study raised no safety concerns in HIV-infected patients stable on lopinavir-based antiretroviral therapy given the recommended artemether-lumefantrine dosage. Increased day-7 lumefantrine concentrations have been shown previously to reduce the risk of malaria treatment failure, but further evidence in adult patients co-infected with malaria and HIV is needed to assess the artemether-lumefantrine risk : benefit profile in this vulnerable population fully. Our antiretroviral-naïve patients confirmed previous findings that lumefantrine absorption is almost saturated at currently recommended doses, but this dose-limited absorption was overcome in the lopinavir group.

Trial registration

Clinical Trial Registration number NCT00869700. Registered on clinicaltrials.gov 25 March 2009

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1345-1) contains supplementary material, which is available to authorized users.

Psychosocial Predictors of Mortality Following Lung Transplantation

Lung transplantation has become an increasingly common treatment for patients with end-stage lung disease. Few studies have examined psychosocial risk factors for mortality in transplant recipients, despite evidence suggesting that elevated levels of negative affect are associated with greater mortality following major cardiac surgery. We therefore examined the relationship between negative affect early after lung transplantation and long-term survival in a sample of 132 lung transplant recipients (28 cystic fibrosis, 64 chronic obstructive pulmonary disease, 26 idiopathic pulmonary fibrosis, 14 other) followed for up to 13.5 years (median 7.4 years) following transplantation. Patients underwent both medical and psychosocial assessments 6 months following transplantation, which included the Beck Depression Inventory-II (BDI-II), Spielberger Anxiety Inventory, and General Health Questionnaire (GHQ). Over the course of follow-up, 80 (61%) participants died. Controlling for demographic factors, native lung disease, disease severity, family income, education level, social support, and frequency of posttransplant rejection, elevated symptoms of depression (BDI-II: HR = 1.31, p = 0.011) and distress (GHQ: HR = 1.28, p = 0.003) were associated with increased mortality. Higher levels of depression and general distress, but not anxiety, measured 6 months following lung transplantation are associated with increased mortality, independent of background characteristics and medical predictors.

A novel framework for discharge uncertainty quantification applied to 500 UK gauging stations

A generalized framework for discharge uncertainty estimation is presentedAllows estimation of place-specific discharge uncertainties for many catchmentsLocal conditions dominate in determining discharge uncertainty magnitudes.

Delirium affects length of hospital stay after lung transplantation

BACKGROUND

Delirium is relatively common after lung transplantation, although its prevalence and prognostic significance have not been systematically studied. The purpose of the present study was to examine pretransplant predictors of delirium and the short-term impact of delirium on clinical outcomes among lung transplant recipients.

METHODS

Participants underwent pretransplant cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status and the Trail Making Test. After transplant, delirium was assessed using the Confusion Assessment Method until discharge.

RESULTS

Sixty-three patients were transplanted between March and November 2013, of which 23 (37%) developed delirium. Among transplanted patients, 48 patients completed pretransplant cognitive testing. Better pretransplant cognitive function was associated with lower risk of delirium (odds ratio, 0.69 [95% confidence interval 0.48, 0.99], P = .043); and demographic and clinical features including native disease (P = .236), the Charlson comorbidity index (P = .581), and the lung allocation score (P = .871) were unrelated to risk of delirium, although there was a trend for women to experience delirium less frequently (P = .071). The presence (P = .006) and duration (P = .027) of delirium were both associated with longer hospital stays.

CONCLUSION

Delirium occurs in more than one-third of patients after lung transplantation. Delirium was associated with poorer pretransplant cognitive functioning and longer hospital stays, after accounting for other medical and demographic factors.

Influence of Doping on the Crystal Potential of Silicon investigated by the Convergent Beam Electron Diffraction Technique

Low index structure potentials of silicon were determined by convergent beam electron diffraction (Kossel-Möllenstedt technique) from very small crystal areas of about 100 Å in diameter. The values of 111, 222, 220, 113 and 004, determined to an accuracy of ±0.03 volts, are in excellent agreement with the accurate X-ray results of Aldred and Hart (see [6], p. 239). Heavy arsenic or phosphorous doping was found to cause a shift of 0.15 volts in the 111 structure potential. Absorption potentials were also determined and found to be 1/3 of the theoretical values published by Radi [20].

Synthesis, characterization, and antiplasmodial activity of polymer-incorporated aminoquinolines

In this research, aminoquinoline compounds were synthesized, characterized, and incorporated into water-soluble polymers to form conjugates. The conjugates were characterized by X-ray diffraction, thermal gravimetric analysis, scanning electron microscope, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy to confirm the successful incorporation of the aminoquinoline compound on to the polymer. The synthesized conjugates were screened for in vitro antiplasmodial activity in triplet test against chloroquine-sensitive strain of Plasmodium falciparum and chloroquine drug was used as a reference drug in all the experiments. A full dose-response was performed to determine the concentration inhibiting 50% of parasite growth (IC50 value). Polymeric conjugates containing 3-diethylamino-1-propylamine solubilizing units were found to be most active against the chloroquine-sensitive strain of P. falciparum.

Polysialyltransferase: a new target in metastatic cancer

Polysialic acid (polySia) is a carbohydrate polymer critical for neuronal cell migration and axon pathfinding in embryonic development. Besides brain regions requiring persistent neuronal plasticity, polySia is essentially absent from the adult body. However, polySia is aberrantly re-expressed on many tumours, where it decorates the surface of NCAM (neuronal cell adhesion molecule) and modulates cell adhesion, migration and invasion. PolySia-NCAM expression is strongly associated with poor clinical prognosis and correlates with aggressive and invasive disease in many cancers, including lung cancer, neuroblastoma and gliomas. The synthesis of polySia is mediated by two polysialyltransferases (polySTs), ST8SiaIV (PST) and particularly ST8SiaII (STX) in cancer cells. The demonstration that polyST knock-down negates events associated with tumour cell dissemination indicates that PST and STX are validated targets. Selective inhibition of polySTs therefore presents a therapeutic opportunity to inhibit tumour invasion and metastasis.

Mitochondrial DNA differentiation between the antitropical blue whiting species Micromesistius poutassou and Micromesistius australis

This study investigated the biogeography and genetic variation in the antitropically distributed Micromesistius genus. A 579 bp fragment of the mitochondrial coI gene was analysed in 279 individuals of Micromesistius poutassou and 163 of Micromesistius australis. The time since divergence was estimated to be c. 2 million years before present (Mb.p.) with an externally derived clock rate by Bayesian methods. Congruent estimates were obtained with an additional data set of cytochrome b sequences derived from GenBank utilizing a different clock rate. The divergence time of 2 Mb.p. was in disagreement with fossil findings in New Zealand and previous hypotheses which suggested the divergence to be much older. It, therefore, appears likely that Micromesistius has penetrated into the southern hemisphere at least two times. Paleoceanographic records indicate that conditions that would increase the likelihood for transequatorial dispersals were evident c. 2-1·6 Mb.p.. Haplotype frequency differences, along with pairwise F(ST) values, indicated that Mediterranean M. poutassou is a genetically isolated population.

Kinetic modelling of the role of the aldehyde dehydrogenase enzyme and the breast cancer resistance protein in drug resistance and transport

A compartmental model for the in vitro uptake kinetics of the anti-cancer agent topotecan (TPT) has been extended from a previously published model. The extended model describes the drug activity and delivery of the pharmacologically active form to the DNA target as well as the catalysis of the aldehyde dehydrogenase (ALDH) enzyme and the elimination of drug from the cytoplasm via the efflux pump. Verification of the proposed model is achieved using scanning-laser microscopy data from live human breast cancer cells. Before estimating the unknown model parameters from the experimental in vitro data it is essential to determine parameter uniqueness (or otherwise) from this imposed output structure. This is formally performed as a structural identifiability analysis, which demonstrates that all of the unknown model parameters are uniquely determined by the output structure corresponding to the experiment.

Helminths: an unrecognised disease burden prevalent among migrants in the gastroenterology clinic

OBJECTIVE

To estimate the prevalence of, and implement a diagnostic strategy for, imported helminth infection in the gastroenterology clinic.

DESIGN

A retrospective study of eosinophil count and probable tropical exposure (phase I) followed by a prospective study of parasitological investigation (phase II).

SETTING

Gastroenterology service of an inner London hospital.

PATIENTS

Adult patients newly attending general gastroenterology and inflammatory bowel disease clinics.

INTERVENTIONS

In phase I, evidence of undiagnosed helminth infection was sought by analysing patient records for associations between eosinophil count and ethnicity. In phase II, a UK guideline for investigation of eosinophilia in migrants was implemented and diagnostic yield determined.

MAIN OUTCOME MEASURES

In phase I, prevalence of eosinophilia was determined; in phase II, helminth prevalence and degree of eosinophilia before and after treatment were reported. Information on symptomatic response to treatment was recorded. Ethnicity was used as a proxy measure for tropical exposure.

RESULTS

426 new patients attended in a 12 month period. Eosinophilia was present in 27 (6.3%). 10/27 (37.0%) patients with eosinophilia were of African or Asian ethnicity whereas only 20% (85/426) of patients overall were from these ethnic groups (χ²=5.27, p=0.02). Following implementation of the protocol, 25/36 migrants with eosinophilia attended for parasitological investigations. Helminth infection was diagnosed in 10/25 (40%). Strongyloidiasis (six patients) and schistosomiasis (three patients) were the most common diagnoses. Median eosinophil count was 1.06×10⁹/l in those with helminths and 0.58×10⁹/l in those without (p=0.004). Eosinophil counts normalised in, and symptomatic improvement was reported by, most patients after treatment.

CONCLUSIONS

Eosinophilia is associated with African or Asian ethnicity in an inner city gastroenterology service. This association is probably explained by imported helminths, which are prevalent in this setting, may be a cause of gastrointestinal symptoms and is easily diagnosed and treated by standard protocols.

Adrenalectomy to treat reactivated chronic hepatitis B infection in a patient with a steroid-secreting adrenal tumour

We present a case of reactivation of chronic hepatitis B virus (HBV) infection by a steroid-producing adrenal tumour. The tumour caused a reactivation and subsequent flare of the patients' HBV. The adrenal tumour was treated with an adrenalectomy and as a consequence the patients' transaminitis and viral load fell rapidly without the need for any additional hepatitis B treatment. The role of hepatitis B and steroid priming is discussed and the possible immunological mechanisms that underpin this phenomenon.

DNA barcoding highlights a cryptic species of grenadier Macrourus in the Southern Ocean

Although three species of the genus Macrourus are recognized in the Southern Ocean, DNA sequencing of the mitochondrial COI gene revealed four well-supported clades. These barcode data suggest the presence of an undescribed species, a conclusion supported by meristic and morphometric examination of specimens.

DNA identification of ciliates associated with disease outbreaks in a New Zealand marine fish hatchery

Ciliates associated with fish mortalities in a New Zealand hatchery were identified by DNA sequencing of the small subunit ribosomal RNA gene (SSU rRNA). Tissue samples were taken from lesions and gill tissues on freshly dead juvenile groper, brain tissue from adult kingfish, and from ciliate cultures and rotifers derived from fish mortality events between January 2007 and March 2009. Different mortality events were characterized by either of 2 ciliate species, Uronema marinum and Miamiensis avidus. A third ciliate, Mesanophrys carcini, was identified in rotifers used as food for fish larvae. Sequencing part of the SSU rRNA provided a rapid tool for the identification and monitoring of scuticociliates in the hatchery and allowed the first identification of these species in farmed fish in New Zealand.

Simultaneous Measurement of Cell Cycle Phase Position and Ionizing Radiation-induced DNA Strand Breakage in Single Human Tumour Cells Using Laser Scanning Confocal Imaging

Techniques for the assessment of DNA damage and repair in individual cells are pertinent to several areas of research, in particular the study of the heterogeneity of tumour cell populations in response to anticancer agents. We describe an adaptation of an in situ alkaline denaturation assay performed on individual nuclei of lysed cells, termed nucleoids, trapped within an agarose film. A novel aspect of the technique described in the application of confocal laser scanning fluorescence microscopy for the measurement of nucleoid relaxation in response to DNA damage. The volumes of spherical nucleoids and their relative DNA contents were determined by ethidium bromide staining and the analysis of confocal sections through the equatorial planes of the nucleoids. Mean nucleoid volume increased as a linear function of X-ray dose (0.5-8 Gy) administered to intact cells prior to lysis. We provide evidence of heterogeneity, in asynchronous cultures, in the DNA unfolding/unwinding characteristics of cells irrespective of cell cycle age. Bivariate plots of relative DNA content versus nucleoid volume allowed the direct assessment of cellular repair capacity with respect to cell cycle position.

Shallow genetic and morphological divergence among seaperches in the South Pacific (family Scorpaenidae; genus Helicolenus)

The phylogenetic relationships among populations of seaperch, Helicolenus spp., in the south-west Pacific were examined with mtDNA markers. Parts of the cytochrome b gene [459 base pair (bp)] and the control region (448 bp) were sequenced in 58 specimens from the south-west Pacific and four specimens of Helicolenus lengerichi from Chile. Only one clade was recognized in New Zealand coastal waters, despite a wide range of colour morphs. This clade also occurred in the mid Tasman Sea on the Norfolk Ridge and around Tasmania and Victoria. A second sympatric clade was identified around Tasmania and Victoria and to the west of New Zealand. A third allopatric clade was identified to the north of New Zealand and in deep water on the Chatham Rise and a fourth clade on the Foundation Seamounts and the Louisville Ridge. Helicolenus lengerichi from Chile formed a fifth clade. Assuming a molecular clock, the clades were estimated to have diverged c. 0.7-2.6 million years ago. Only two clades, around Tasmania and Victoria, were separated using morphology, colour (in live) and dorsal-fin soft ray counts and were confirmed as Helicolenus percoides and Helicolenus barathri. Two characters, orbit diameter and colour variation, previously used to identify two species in New Zealand waters were unreliable characters for species discrimination. Principle component analyses of 11 morphological measures from 67 individuals did not delineate the clades. A canonical discriminant analysis was able to separate four of the five clades, but mean discriminate probabilities were low (77.6%), except for the five Chilean specimens of H. lengerichi (100%).

Investigating South African plants as a source of new antimalarial drugs

Based on the historical success of natural products as antimalarial drugs and the urgent need for new antimalarials, a number of South African medicinal plants have been evaluated for their antimalarial properties. This paper reviews the major studies conducted and their findings. Overall three ethnobotanical screening programmes have been conducted on South African plants while there have been a few studies adopting a more direct approach, where plants within a particular genus were screened for antiplasmodial activity. The paper also summarizes the bioactive molecules identified from selected plants having antiplasmodial activity. Overall the results of all studies conducted to date confirm the potential of South African medicinal plants in antimalarial drug discovery and identified a number of promising taxa and compounds for further investigation as plant-based antimalarial agents.

A coupled drug kinetics-cell cycle model to analyse the response of human cells to intervention by topotecan

A model describing the response of the growth of single human cells in the absence and presence of the anti-cancer agent topotecan (TPT) is presented. The model includes a novel coupling of both the kinetics of TPT and cell cycle responses to the agent. By linking the models in this way, rather than using separate (disjoint) approaches, it is possible to illustrate how the drug perturbs the cell cycle. The model is compared to experimental in vitro cell cycle response data (comprising single cell descriptors for molecular and behavioural events), showing good qualitative agreement for a range of TPT dose levels.

Mitochondrial phylogeography of New Zealand freshwater crayfishes, Paranephrops spp

Tectonic movement at the boundary of the Indo-Australian and Pacific Plates during the Miocene and Pliocene is recognized as a driving force for invertebrate speciation in New Zealand. Two endemic freshwater crayfish (koura) species, Paranephrops planifrons White 1842 and Paranephrops zealandicus White 1842, represent good model taxa to test geological hypotheses because, due to their low dispersal capacity and life history, geographical restriction of populations may be caused by vicariant processes. Analysis of a mitochondrial DNA marker (cytochrome oxidase subunit I) reveals not two, but three major koura lineages. Contrary to expectation, the cryptic West Coast group appears to be more closely related to P. zealandicus than to P. planifrons and has diverged earlier than the final development (Late Pleistocene) of Cook Strait. Our date estimates suggest that koura lineage diversification probably coincided with early to mid-Alpine orogeny in the mid-Pliocene. Estimates of node ages and the phylogenies are inconsistent with both ancient Oligocene and recent postglacial Pleistocene range expansion, but suggest central to north colonization of North Island and west to east movement in South Island during mid- to late Pliocene. Crypsis and paraphyly of the West Coast group suggest that morphological characters presently used to classify koura species could be misleading.

Early bactericidal activity of high-dose rifampin in patients with pulmonary tuberculosis evidenced by positive sputum smears

We studied the early bactericidal activity of twice the standard dose of rifampin in subjects with pulmonary tuberculosis evidenced by positive smears. The observed mean 2-day activity was almost double that reported at the standard dose. Further studies are warranted to establish whether higher rifampin doses might assist in shortening tuberculosis treatment.

Transcatheter embolisation of patent ductus arteriosus using an Amplatzer vascular plug in six dogs

OBJECTIVES

The objective of this study was to assess the feasibility of transcatheter embolisation of a patent ductus arteriosus using an Amplatzer vascular plug (Amplatzer Medical UK) in six dogs.

METHODS

The Amplatzer vascular plug is a self-expandable, cylindrical device attached to a delivery cable. In all the dogs, the device was delivered transvenously. Successful device implantation was defined as firm anchorage of the device squarely within the distal part of the ductus arteriosus with no intra- or postoperative dislodgement. Successful occlusion of the ductus arteriosus occurred if a disappearance of the continuous murmur was achieved 24 hours after placement of the Amplatzer vascular plug.

RESULTS

The age of the dogs ranged from 16 weeks to 7.5 years. Their weights ranged from 2.9 to 27.6 kg (median 6 kg). Two dogs had congestive heart failure before embolisation. Successful device implantation was achieved in all dogs. Successful occlusion of the ductus arteriosus was achieved in four of the six dogs. Complications included mild lameness, residual shunting, and bruising and pruritus around the surgical wound site. At follow-up, two dogs had a continuous murmur and one required treatment for congestive heart failure.

CLINICAL SIGNIFICANCE

This technique may represent a clinically effective and less expensive alternative to the use of an Amplatzer duct occluder (Amplatzer Medical UK) in dogs with medium-sized patent ductus arteriosus. Further investigations are required to fully evaluate its efficacy and safety in various sizes and types of patent ductus arteriosus, and to determine the optimal device size in relation to the size of the ductus.

Modification to improve efficiency of sampling schedules for BA/BE testing of FDC anti-tuberculosis drugs

SETTING

The assessment of rifampicin (RMP) containing fixed-dose combination (FDC) formulations using in vivo bioequivalence testing is widely accepted. It would be advantageous for both the drug regulatory authorities and drug manufacturers, for optimum minimum blood testing time intervals that encompass all anti-tuberculosis active constituents in the FDC to be established.

OBJECTIVE

To determine the optimum blood sampling schedule for testing novel FDC anti-tuberculosis drugs, isoniazid, RMP, pyrazinamide and ethambutol

DESIGN

The results of 12 different single-dose, two-way cross-over designs are presented. The studies determined the bioavailability and bioequivalence of RMP-containing FDCs, and conformed with the requirements of the South African national drug regulatory authority for each of the active constituents.

RESULTS

The pharmacokinetic parameters to determine bioavailability and the Hauschke method to determine bioequivalence revealed that a six-point time protocol, namely 0, 1, 2, 4, 6 and 8 h, provides a good approximation of the area under the curve, and that an 11-point time protocol of 0, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6 and 8 h provided information comparable to the conventional 15 time-points for FDCs containing up to four drugs.

CONCLUSION

The findings provide concrete economic benefit and convenience for quality assurance testing of existing and novel FDCs.

QSAR models based on quantum topological molecular similarity

A new method called quantum topological molecular similarity (QTMS) was fairly recently proposed [J. Chem. Inf. Comp. Sc., 41, 2001, 764] to construct a variety of medicinal, ecological and physical organic QSAR/QSPRs. QTMS method uses quantum chemical topology (QCT) to define electronic descriptors drawn from modern ab initio wave functions of geometry-optimised molecules. It was shown that the current abundance of computing power can be utilised to inject realistic descriptors into QSAR/QSPRs. In this article we study seven datasets of medicinal interest : the dissociation constants (pK(a)) for a set of substituted imidazolines , the pK(a) of imidazoles , the ability of a set of indole derivatives to displace [(3)H] flunitrazepam from binding to bovine cortical membranes , the influenza inhibition constants for a set of benzimidazoles , the interaction constants for a set of amides and the enzyme liver alcohol dehydrogenase , the natriuretic activity of sulphonamide carbonic anhydrase inhibitors and the toxicity of a series of benzyl alcohols. A partial least square analysis in conjunction with a genetic algorithm delivered excellent models. They are also able to highlight the active site, of the ligand or the molecule whose structure determines the activity. The advantages and limitations of QTMS are discussed.

Potent cytotoxicity and inhibition of pan-cell cycle progression by Alchemix, a novel alkylating anthraquinone

12030

Introduction: DNA topoisomerase II (topo II) is crucial to the maintenance of cancer cells in a proliferative state. DNA intercalation is a crucial part of topo II inhibition by DNA affinic anthraquinones. Potent cytotoxicity of anthraquinones, is related to their slow rate of dissociation from DNA, the kinetics of which favours long-term trapping of the topo-DNA complexes. Currently available DNA interacting agents at best promote a transient inhibition of topo II, since the topo-drug-DNA ternary complex is reversed by removal of the intracellular drug pool. Results: Alchemix cell cycle events: DNA content and Cyclin B1 expression were measured using flow cytometry and a p53 functional human osteosarcoma cell line (U2-OS) The results indicate: (ii) slow pan-cell cycle progression and mitotic commitment with a limited expression of G2 arrest, (iii) B1 cyclin tracking reveals that escape from Alchemix-induced cell cycle arrest in G2 is forcing some cells to enter polyploidy via an aberrant mitosis in keeping with topoisomerase II inhibition. Alchemix in vitro activity against the NCI human cell line panel including several drug resistant cancer cell lines had a mean IG50 = 49 nM. 11 of the 24 cell lines tested have an IG50 of <10 nM. Alchemix retains potent activity against chemotherapy resistant tumors including drug resistant ones. Conclusions: Alchemix possesses potent activity across a variety of different human tumors and significantly shows potent activity in cisplatin and anthracyline resistant human tumors Alchemix has pan-cell cycle effects. Multilevel targeting by Alchemix reduces the probability of evasion of cell cycle related pharmacodynamic responses. Results help explain the activity of Alchemix in both cisplatin and anthracycline resistant tumors in vitro and in vivo.

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Effect of spinal flexion on the conus medullaris: a case series using magnetic resonance imaging

Anatomy textbooks state that the conus medullaris moves cephalad when the vertebral column is flexed. This could confer protection against spinal cord damage during dural puncture, but has not been demonstrated in vivo. We therefore imaged the spine of 10 volunteers using magnetic resonance imaging to determine if such movement occurs with the spine in the neutral and flexed positions. The position of the conus medullaris in relation to the superior endplate of the L1 vertebra was determined. On spinal flexion, the conus medullaris moved cephalad in three subjects and caudad in three subjects, with no change in the remaining four. The median overall movement (95% CI [range]) was 0 mm (4 mm caudad to 1 mm cephalad [3 mm caudad to 1 mm cephalad]; p = 1.0). Whilst spinal flexion may facilitate needle insertion during dural puncture, it is unlikely to confer extra protection against spinal cord damage.

Pigmented villonodular synovitis of the hip mimicking soft-tissue sarcoma: a case report

Pigmented villonodular synovitis is a rare and benign but potentially locally aggressive disease that should be considered in younger patients who present with monoarticular joint symptoms and pathology. We present a 30-year-old Sudanese woman with a huge mass arising from the right hip joint. A multimodality radiological approach to investigation and diagnosis is demonstrated and discussed. Histopathological examination of the resected specimen confirmed the diagnosis of pigmented villonodular synovitis with the mass consisting of a proliferation of fibrohistiocytic cells, abundant haemosiderin, foamy histiocytes, and occasional giant cells. The patient made a good recovery, with mobility aided by arm crutches and a hip abduction brace.