Cognitive mechanisms and resilience in UK-based general practitioners: cross-sectional findings.

BACKGROUND: Being a general practitioner (GP) is a stressful occupation, and the strain GPs are under can have negative effects on their psychological well-being, as well as on the patients' experience of healthcare. Resilience can help buffer against this and is a dynamic process by which one can cope with adversity and stress. AIMS: This study aimed to identify modifiable cognitive mechanisms related to resilience in GPs, specifically interpretation bias and cognitive reappraisal. METHODS: One hundred and fourteen GPs completed an online cross-sectional correlational study. This comprised questionnaires assessing resilience, emotional distress, work environment and cognitive mechanisms (emotion regulation), as well as a task assessing interpretation bias. RESULTS: Resilience of GPs was negatively correlated with measures of emotional distress. Furthermore, resilience was positively correlated with positive interpretation bias (r = 0.60, ρ = 0.60, P < 0.01) and cognitive reappraisal (r = 0.39, ρ = 0.40, P < 0.01). In a hierarchical regression, positive interpretation bias (B = 0.25, SE B = 0.06, ß = 0.39, P < 0.01) was a significant independent predictor of resilience when controlling for depression, anxiety and stress. CONCLUSIONS: This is the first study to establish an association between resilience and positive interpretation bias and cognitive reappraisal in GPs. Future research should use longitudinal designs to determine if they have a causal role in promoting resilience, and importantly whether interventions focusing on these processes may foster resilience in less resilient GPs.

Urinary B-cell-activating factor of the tumour necrosis factor family (BAFF) in systemic lupus erythematosus.

INTRODUCTION: We examined the clinical relevance of urinary concentrations of B-cell-activating factor of the tumour necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) in systemic lupus erythematosus (SLE). METHODS: We quantified urinary BAFF (uBAFF) by enzyme-linked immunosorbent assay in 85 SLE, 28 primary Sjögren syndrome (pSS), 40 immunoglobulin A nephropathy (IgAN) patients and 36 healthy controls (HCs). Urinary APRIL (uAPRIL) and monocyte chemoattractant protein 1 (uMCP-1) were also quantified. Overall and renal SLE disease activity were assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000. RESULTS: uBAFF was detected in 12% (10/85) of SLE patients, but was undetectable in HCs, IgAN and pSS patients. uBAFF was detectable in 28% (5/18) of SLE patients with active nephritis vs 5/67 (7%) of those without ( p = 0.03), and uBAFF was significantly higher in active renal patients ( p = 0.02) and more likely to be detected in patients with persistently active renal disease. In comparison, uAPRIL and uMCP-1 were detected in 32% (25/77) and 46% (22/48) of SLE patients, respectively. While no difference in proportion of samples with detectable uAPRIL was observed between SLE, HCs and IgAN patients, both uAPRIL and uMCP-1 were significantly detectable in higher proportions of patients with active renal disease. CONCLUSIONS: uBAFF was detectable in a small but a significant proportion of SLE patients but not in other groups tested, and was higher in SLE patients with active renal disease.

A deep look into thin melanomas: What's new for the clinician and the impact on the patient.

Melanoma incidence and mortality are on the rise and although most new cases of melanoma are thin, a significant percentage of these patients still experience disease progression. The American Joint Committee on Cancer publishes staging criteria for melanoma, which were recently updated to the 8th edition. The most significant revision from the 7th edition affects the T1b classification, which now includes melanomas with a Breslow depth of 0.8 mm to 1.0 mm. The second major revision eliminates mitoses as a criterion to upstage a thin melanoma to T1b. Although mitotic figures have been established as an independent prognostic factor, they do not have a significant correlation with sentinel lymph node (SLN) biopsy positivity. SLN status remains the most important independent prognostic factor in thin melanomas. Nonetheless, the identification of patients who are at the highest risk for having a positive SLN test result remains difficult. Importantly, a positive SLN test result has high positive predictive value, but a negative one has very low negative predictive value. Since there is no proven survival benefit in performing an SLN biopsy in T1 disease, dermatologists need to have a personalized discussion with patients with thin melanomas to review expected risks and benefits before undertaking this procedure.

Vasoconstrictor stimulus determines the functional contribution of myoendothelial feedback to mesenteric arterial tone.

KEY POINTS: In isolated resistance arteries, endothelial modulation of vasoconstrictor responses to α1 -adrenoceptor agonists occurs via a process termed myoendothelial feedback: localized inositol trisphosphate (InsP3 )-dependent Ca2+ transients activate intermediate conductance Ca2+ -activated K+ (IKCa ) channels, hyperpolarizing the endothelial membrane potential to limit further reductions in vessel diameter. We demonstrate that IKCa channel-mediated myoendothelial feedback limits responses of isolated mesenteric arteries to noradrenaline and nerve stimulation, but not to the thromboxane A2 mimetic U46619 or to increases in intravascular pressure. In contrast, in the intact mesenteric bed, although responses to exogenous noradrenaline were limited by IKCa channel-mediated myoendothelial feedback, release of NO and activation of endothelial small conductance Ca2+ -activated K+ (SKCa ) channels in response to increases in shear stress appeared to be the primary mediators of endothelial modulation of vasoconstriction. We propose that (1) the functional contribution of myoendothelial feedback to arterial tone is determined by the nature of the vasoconstrictor stimulus, and (2) although IKCa channel-mediated myoendothelial feedback may contribute to local control of arterial diameter, in the intact vascular bed, increases in shear stress may be the major stimulus for engagement of the endothelium during vasoconstriction. ABSTRACT: Constriction of isolated resistance arteries in response to α1 -adrenoceptor agonists is limited by reciprocal engagement of inhibitory endothelial mechanisms via myoendothelial feedback. In the current model of feedback, agonist stimulation of smooth muscle cells results in localized InsP3 -dependent Ca2+ transients that activate endothelial IKCa channels. The subsequent hyperpolarization of the endothelial membrane potential then feeds back to the smooth muscle to limit further reductions in vessel diameter. We hypothesized that the functional contribution of InsP3 -IKCa channel-mediated myoendothelial feedback to limiting arterial diameter may be influenced by the nature of the vasoconstrictor stimulus. To test this hypothesis, we investigated the functional role of myoendothelial feedback in modulating responses of rat mesenteric resistance arteries to the adrenoceptor agonist noradrenaline, the thromboxane A2 mimetic U46619, increases in intravascular pressure and stimulation of perivascular sympathetic nerves. In isolated arteries, responses to noradrenaline and stimulation of sympathetic nerves, but not to U46619 and increases in intravascular pressure, were modulated by IKCa channel-dependent myoendothelial feedback. In the intact mesenteric bed perfused under conditions of constant flow, responses to exogenous noradrenaline were modulated by myoendothelial feedback, but shear stress-induced release of NO and activation of endothelial SKCa channels appeared to be the primary mediators of endothelial modulation of vasoconstriction to agonists and nerve stimulation. Thus, we propose that myoendothelial feedback may contribute to local control of diameter within arterial segments, but at the level of the intact vascular bed, increases in shear stress may be the major stimulus for engagement of the endothelium during vasoconstriction.

Warty (follicular) dyskeratoma on the mons pubis.

Warty (follicular) dyskeratoma (WD) is a discrete nodular lesion that demonstrates the characteristic histopathologic findings of acantholysis and dyskeratosis. WDs most commonly occur on the head and neck of adults. We present a case of WD that occurred on the mons pubis of a 53-year-old woman. Only a few other cases of WDs occurring on the vulva have been reported. WD most likely represents a tumor of the follicular infundibulum. Despite its name, there is no evidence that WD is caused by a human papillomavirus (HPV) infection. Although occurrences on the vulva are rare, they must be distinguished from HPV-induced squamous tumors when found in this area.

Anaesthetic management of patients undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei: a retrospective audit.

Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has been shown to improve quality of life and survival rates in patients suffering from pseudomyxoma peritonei. The procedure is long and associated with significant intraoperative blood loss. As such, the anaesthetic management of patients undergoing this procedure can be challenging. The aim of this paper is to describe our perioperative management of pseudomyxoma peritonei patients who received CRS and to report a retrospective audit of our outcomes and complications over a six-year period at a large tertiary centre. A total of 70 patients were included, of whom three (4.3%) had CRS alone, 42 (60.0%) had CRS with HIPEC, and 25 (35.7%) had CRS with HIPEC and early postoperative intraperitoneal chemotherapy. There were no intraoperative deaths. A total of four patients (5.7%) died during their hospital admission. At one-year follow-up, six patients (9.0%) had died, and at the end of the study 15 (22.4%) had died. No statistically significant difference in blood loss was seen between patients who received tranexamic acid (30 patients, 42.9%) and those who did not, but the incidence of deep venous thrombosis was much higher (10/30 versus 1/40). Different intravenous fluid strategies appeared not to influence the incidence of postoperative acute renal failure. Further research is required to evaluate the effects of intraoperative tranexamic acid and different intraoperative fluid strategies on outcomes in patients undergoing CRS with HIPEC.

Gaps and barriers in health-care provision for co-morbid diabetes and chronic kidney disease: a cross-sectional study.

BACKGROUND: Patients with diabetes and chronic kidney disease (CKD) are a complex subset of the growing number of patients with diabetes, due to multi-morbidity. Gaps between recommended and received care for diabetes and chronic kidney disease (CKD) are evident despite promulgation of guidelines. Here, we document gaps in tertiary health-care, and the commonest patient-reported barriers to health-care, before exploring the association between these gaps and barriers. METHODS: This cross-sectional study recruited patients with diabetes and CKD (eGFR < 60 mL/min/1.73 m2) across 4 large hospitals. For each patient, questionnaires were completed examining clinical data, recommended care, and patient-reported barriers limiting health-care. Descriptive statistics, subgroup analyses by CKD stage and hospital, and analyses examining the relationship between health-care gaps and barriers were performed. RESULTS: 308 patients, of mean age 66.9 (SD 11.0) years, and mostly male (69.5%) and having type 2 diabetes (88.0%), participated. 49.1% had stage 3, 24.7% stage 4 and 26.3% stage 5 CKD. Gaps between recommended versus received care were evident: 31.9% of patients had an HbA1c ≥ 8%, and 39.3% had a measured blood pressure ≥ 140/90 mmHg. The commonest barriers were poor continuity of care (49.3%), inadequate understanding/education about CKD (43.5%), and feeling unwell (42.6%). However, barriers associated with a failure to receive items of recommended care were inadequate support from family and friends, conflicting advice from and poor communication amongst specialists, the effect of co-morbidities on self-management and feeling unmotivated (all p < 0.05). CONCLUSIONS: Barriers to health-care varied across CKD stages and hospitals. Barriers associated with a deviation from recommended care were different for different items of care, suggesting that specific interventions targeting each item of care are required.

Effectiveness of endoscopic cricopharyngeal myotomy in adults with neurological disease: systematic review.

OBJECTIVE: To determine the effectiveness of endoscopic cricopharyngeal myotomy on upper oesophageal sphincter dysfunction in adults with upper oesophageal sphincter dysfunction and neurological disease. DATA SOURCES: Published and unpublished studies with a quasi-experimental design investigating endoscopic cricopharyngeal myotomy effects on upper oesophageal sphincter dysfunction in humans were considered eligible. Electronic databases, grey literature and reference lists of included studies were systematically searched. REVIEW METHODS: Data were extracted by two independent reviewers. Methodological quality was assessed independently using the PEDro scale and MINORS tool. RESULTS: Of 2938 records identified, 2 studies were eligible. Risk of bias assessment indicated areas of methodological concern in the literature. Statistical analysis was not possible because of the limited number of eligible studies. CONCLUSION: No determinations could be made regarding endoscopic cricopharyngeal myotomy effectiveness in the cohort of interest. Reliable and valid evidence on the following is required to support increasing clinical usage of endoscopic cricopharyngeal myotomy: optimal candidacy selection; standardised post-operative management protocol; complications; and endoscopic cricopharyngeal myotomy effects on aspiration of food and laryngeal penetration, mean upper oesophageal sphincter resting pressure and quality of life.

Population Genetic Structure and Potential Incursion Pathways of the Bluetongue Virus Vector Culicoides brevitarsis (Diptera: Ceratopogonidae) in Australia.

Culicoides brevitarsis is a vector of the bluetongue virus (BTV), which infects sheep and cattle. It is an invasive species in Australia with an assumed Asian/South East Asian origin. Using one mitochondrial marker (i.e., part of the cytochrome oxidase subunit I gene) and six nuclear markers, we inferred population genetic structure and possible incursion pathways for Australian C. brevitarsis. Nine mitochondrial haplotypes, with low nucleotide sequence diversity (0.0-0.7%) among these, were identified in a sample of 70 individuals from seven sites. Both sets of markers revealed a homogeneous population structure, albeit with evidence of isolation by distance and two genetically distinct clusters distributed along a north-to-south cline. No evidence of a cryptic species complex was found. The geographical distribution of the mitochondrial haplotypes is consistent with at least two incursion pathways into Australia since the arrival of suitable livestock hosts. By contrast, 15 mitochondrial haplotypes, with up to four times greater nucleotide sequence diversity (0.0-2.9%) among these, were identified in a sample of 16 individuals of the endemic C. marksi (sampled from a site in South Australia and another in New South Wales). A phylogenetic tree inferred using the mitochondrial marker revealed that the Australian and Japanese samples of C. brevitarsis are as evolutionarily different from one another as some of the other Australian species (e.g., C. marksi, C. henryi, C. pallidothorax) are. The phylogenetic tree placed four of the species endemic to Australia (C. pallidothorax, C. bundyensis, C. marksi, C. henryi) in a clade, with a fifth such species (C. bunrooensis) sharing a common ancestor with that clade and a clade comprising two Japanese species (C. verbosus, C. kibunensis).

BK Virus Associated Nephropathy, a Cause of Early Renal Allograft Dysfunction: A Single Centre Study.

BACKGROUND: BK virus associated nephropathy (BKVN) is an important cause of early graft dysfunction in renal transplant recipients. The present study was carried out to determine the burden of BKVN in a single renal transplant centre in Australia. METHOD: A retrospective analysis of de novo renal transplant recipients from 2010 to 2013 was performed to identify biopsy proven BKVN. Estimated glomerular filtration rate (eGFR) was compared at baseline, at BKVN diagnosis and 3 and 12 months postdiagnosis. RESULT: Of the 317 de novo renal transplants recipients in the study period, 20 (6.3%) developed BKVN. The mean age was 54.8 ± 13.1 years and 13 (65%) were male. The mean time from transplant to BKVN was 8.7 ± 6.7 months with 17 (85%) diagnosed within 12 months. Four recipients each were diagnosed BKVN on 3 and 12 month surveillance biopsy. Six (30%) had normal eGFR at diagnosis. Mean eGFR at diagnosis was 38.8 ± 19.2 ml/min/1.73 m2, which was significantly lower (p < 0.01) than that at baseline (50.3 ± 16.4 ml/min/1.73 m2). eGFR improved numerically at 3 and 12 months post-diagnosis, however the difference was not significant. One patient had graft failure, 19 months after diagnosis. CONCLUSION: BKVN generally occurs in first post-transplant year and is an important cause of early graft dysfunction. Surveillance biopsy helps in detecting subclinical BKVN.

One cancer destroys another: short report of a myeloid sarcoma causing ischaemic necrosis of an adenocarcinoma.

We present a highly unusual case and histological images of a patient who underwent complete resection of a perforated caecal adenocarcinoma caused by angiodestruction of the proximal vasculature by a distinct acute myeloid infiltrate. Both tumours were removed in their entirety at one visit to theatre and the patient remains well and in remission 18 months later.

Vancomycin-resistant enterococci colonization does not increase mortality in end-stage kidney failure: a case-control study.

BACKGROUND: Vancomycin-resistant enterococci (VRE) colonization is a frequent occurrence in patients with renal failure. Understanding the impact of VRE colonization on this group of patients has considerable clinical applicability. AIM: To understand whether VRE colonization in renal patients has an impact on number of admissions to hospital, length of stay, and mortality. METHODS: A retrospective case-control study of renal dialysis patients was performed between 2000 and 2010. Cases were 134 VRE-colonized patients requiring renal replacement therapy and matched controls were 137 non-colonized patients with the same baseline characteristics. Matched cases and controls were analysed for differences in number of admissions, length of stay, and mortality. FINDINGS: There was no difference in mortality between colonized and non-colonized patients (hazard ratio: 1.14; 95% confidence interval: 0.78-1.69; P = 0.49). Length of stay for colonized patients was 7.29 days compared with 4.14 days (P < 0.001). The number of admissions for VRE-colonized patients was not significantly different compared with controls (9.34 vs 8.33, P = 0.78). CONCLUSION: VRE colonization did not increase mortality in renal patients but did contribute to increased length of stay.

Cinacalcet reduces plasma intact parathyroid hormone, serum phosphate and calcium levels in patients with secondary hyperparathyroidism irrespective of its severity.

AIMS: To evaluate the relationship between the severity of secondary hyperparathyroidism (SHPT) - defined in terms of baseline plasma intact parathyroid hormone (iPTH) level - and the magnitude of response to cinacalcet. MATERIALS AND METHODS: In this post hoc analysis, data were pooled from three randomized, placebo-controlled trials in which dialysis patients with iPTH ≥ 300 pg/ml were dose-titrated with cinacalcet or placebo in addition to conventional treatment to achieve iPTH ≤ 250 pg/ml. In 953 patients analyzed (cinacalcet, 545; placebo, 408), baseline iPTH levels were categorized in 100 pg/ml intervals (300 - ≥ 1,000 pg/ml), and the impact of baseline iPTH on changes in iPTH, phosphate (P), calcium (Ca) and calcium- phosphate product (Ca × P) was evaluated. RESULTS: Cinacalcet reduced iPTH (47% reduction), P (9%), Ca (7%), and Ca × P (15%) across all subgroups. For patients receiving cinacalcet, the mean percentage reduction from baseline in iPTH varied from 35 to 55%, being consistently decreased across the severity subgroups. The mean absolute change in iPTH was more pronounced in patients with higher baseline iPTH levels, particularly in the ≥ 1,000 pg/ml subgroup vs. the other subgroups. However, as baseline iPTH levels increased, iPTH ≤ 250 pg/ml was achieved in fewer patients. A trend towards greater absolute change from baseline was observed for P in patients with more severe disease (iPTH ≥ 800 pg/ml) treated with cinacalcet compared with patients with less severe disease (iPTH 300 - < 800 pg/ml). CONCLUSIONS: Cinacalcet lowers plasma iPTH and serum P, Ca and Ca × P levels in dialysis patients with SHPT, regardless of disease severity. Patients with more severe disease experienced greater reductions in PTH and P, but fewer achieved iPTH ≤ 250 pg/ml by the efficacy assessment phase. Use of cinacalcet when baseline PTH is lower may result in more stable control of SHPT and help to control bone and mineral alterations.

Acute tetraplegia and cardiac arrest following high cervical leptomeningeal metastasis of giant cell glioblastoma.

Giant cell glioblastoma multiforme (gcGBM) is an unusual subtype of high-grade glioma (grade IV, World Health Organization classification). We report a patient with a rare acute tetraplegia, followed by lethal cardiac arrest, who had undergone a prior resection of a supratentorial gcGBM. Neuroradiological workup revealed a large, high cervical compressive leptomeningeal mass consistent with a drop metastasis. Due to the possibility of a rapid clinical deterioration in patients with high cervical cord compression, the diagnosis of drop metastasis to the spine should be considered in patients with a previous history of supratentorial GBM who present with acute diffuse motor weakness.

Surgical management of melanoma brain metastases in patients treated with immunotherapy.

OBJECT: Despite the increasing use of immunotherapy in the treatment of metastatic melanoma, the effects of this therapy on the management of patients with associated brain metastases are not completely defined. The authors undertook this study to determine the effectiveness of resection and the effects of immunotherapy on brain metastasis management. METHODS: The authors analyzed data pertaining to consecutive patients with metastatic melanoma treated with immunotherapy within 3 months of discovery of brain metastases that were surgically resected. RESULTS: Forty-one patients (median age 44.4 years, range 19.2-63.1 years) underwent resection of 53 brain metastases (median number of metastases 1, range 1-4). The median metastasis volume was 2.5 cm(3). Fifteen patients underwent whole-brain radiation therapy (WBRT) and 26 patients did not. Duration of survival from brain metastasis diagnosis was not significantly different between patients who received WBRT (mean 24.9 months) and those who did not (mean 23.3 months) (p > 0.05). Local and distant brain recurrence rates were not statistically different between the WBRT (7.1% and 28.6%, respectively) and non-WBRT (7.7% and 41.0%) groups for the duration of follow-up (p > 0.05). An objective systemic response to immunotherapy was associated with increased duration of survival (p < 0.05). CONCLUSIONS: Resection of melanoma brain metastases in patients treated with immunotherapy provides excellent local control with low morbidity. An objective response to systemic immunotherapy is associated with a prolonged survival in patients who have undergone resection of melanoma brain metastases. Moreover, adjuvant WBRT in melanoma immunotherapy patients with limited metastatic disease to the brain does not appear to provide a significant survival benefit.

Advanced chronic kidney disease, cardiovascular events and the effect of diabetes: data from the Atherosclerosis and Folic Acid Supplementation Trial.

BACKGROUND: End-stage kidney disease registry data have reported increased mortality in patients with diabetes as compared with those without. Here we examine whether diabetes is independently associated with an increased risk of major cardiovascular events and death in patients with advanced chronic kidney disease (CKD). METHODS: Data from 315 participants with CKD in the Atherosclerosis and Folic Acid Supplementation Trial (ASFAST) were assessed. Primary end-points were fatal or non-fatal cardiovascular events, including myocardial infarction, stroke, unstable angina, coronary revascularisation and peripheral vascular events assessed both jointly and separately using Cox-proportional hazard models. RESULTS: Twenty-three per cent reported diabetes. Median follow up was 3.6 years. In those with diabetes, an increased risk for major cardiovascular events was observed, crude hazard ratio (HR) 2.87 (95% confidence interval (CI) 2.11-3.90). After adjustment for age, gender, smoking, systolic blood pressure, body mass index, past ischaemic heart disease and use of preventive therapies, diabetes was associated with an HR of 1.83 (1.28-2.61) for major cardiovascular events. The risk for peripheral vascular events was also increased, adjusted HR 6.31 (2.61-15.25). For all-cause death, major coronary and stroke events, the risk in those with diabetes was not significantly increased (all-cause death, adjusted HR 1.31 (95% CI 0.80-2.14); major coronary events, adjusted HR 1.26 (95% CI 0.64-2.49); and major stroke events, adjusted HR 1.28 (95% CI 0.55-2.99)). CONCLUSIONS: Diabetes significantly increases the risk of major cardiovascular events, especially peripheral vascular events in patients with advanced CKD. Trials of multifactorial management of cardiovascular risk factors are required to determine if outcomes for this population may be improved.

Mucosa-associated lymphoma tissue of the dura presenting as meningioma.

Mucosa-associated lymphoma tissue (MALT) of the dura is extremely rare, with only a few reported cases worldwide. We present a unique case of a 61-year-old female who presented with neurologic symptoms of unsteady gait, dizziness, and sharp pain on her scalp for 3 weeks. A subsequent magnetic resonance imaging (MRI) of the brain demonstrated a dural-based mass radiographically consistent with meningioma. However, biopsy revealed the cells to be immunopositive for CD20 and CD79a, and immunonegative for CD5, CD10, CD43, and CD23. The neoplastic small lymphoid B cells were MUM1 positive and showed kappa light chain restriction, consistent with MALT of the dura. No evidence of systemic disease was found. The patient underwent radiation, which resulted in a complete response. MALT lymphoma, while rare, must be considered in the differential diagnosis in patients presenting radiographically with meningioma.

Host-specificity of myxoma virus: Pathogenesis of South American and North American strains of myxoma virus in two North American lagomorph species.

The pathogenesis of South American and North American myxoma viruses was examined in two species of North American lagomorphs, Sylvilagus nuttallii (mountain cottontail) and Sylvilagus audubonii (desert cottontail) both of which have been shown to have the potential to transmit the South American type of myxoma virus. Following infection with the South American strain (Lausanne, Lu), S. nuttallii developed both a local lesion and secondary lesions on the skin. They did not develop the classical myxomatosis seen in European rabbits (Oryctolagus cuniculus). The infection at the inoculation site did not resolve during the 20-day time course of the trial and contained transmissible virus titres at all times. In contrast, S. audubonii infected with Lu had very few signs of disseminated infection and partially controlled virus replication at the inoculation site. The prototype Californian strain of myxoma virus (MSW) was able to replicate at the inoculation site of both species but did not induce clinical signs of a disseminated infection. In S. audubonii, there was a rapid response to MSW characterised by a massive T lymphocyte infiltration of the inoculation site by day 5. MSW did not reach transmissible titres at the inoculation site in either species. This might explain why the Californian myxoma virus has not expanded its host-range in North America.

Molecular and serological analysis of the epidemiology of myxoma virus in rabbits.

The epidemiology of myxoma virus was studied by serology and molecular analysis of restriction fragment length polymorphisms (RFLPs) in genomic DNA. 159 isolates of myxoma virus were made over a period of 5 spring/summer epidemics from 12 field sites in south-eastern Australia. Virus isolates were classified into 10 genetic types using RFLPs detected with a panel of nine restriction endonucleases. Between 3 and 6 different genetic types were found during spring/summer periods across all sites and up to 3 different genetic types were isolated during an epidemic on a single site. The predominant type tended to change each year. A widespread mutation was identified in two genetic types with replacement of the 3' two-thirds of the M009L gene at the left hand inverted terminal repeat junction with a duplication of the region containing the M156R, M154L and M153R genes from the right hand end of the genome. This demonstrated how myxoma virus can potentially evolve by expansion of the inverted terminal repeat boundaries.

Simultaneous freeze tolerance and avoidance in individual fungus gnats, Exechia nugatoria.

Freeze tolerance and freeze avoidance are typically described as mutually exclusive strategies for overwintering in animals. Here we show an insect species that combines both strategies. Individual fungus gnats, collected in Fairbanks, Alaska, display two freezing events when experimentally cooled and different rates of survival after each event (mean +/- SEM: -31.5 +/- 0.2 degrees C, 70% survival and -50.7 +/- 0.4 degrees C, 0% survival). To determine which body compartments froze at each event, we dissected the abdomen from the head/thorax and cooled each part separately. There was a significant difference between temperature levels of abdominal freezing (-30.1 +/- 1.1 degrees C) and head/thorax freezing (-48.7 +/- 1.3 degrees C). We suggest that freezing is initially restricted to one body compartment by regional dehydration in the head/thorax that prevents inoculative freezing between the freeze-tolerant abdomen (71.0 +/- 0.8% water) and the supercooled, freeze-sensitive head/thorax (46.6 +/- 0.8% water).