Molnupiravir versus placebo in unvaccinated and vaccinated patients with early SARS-CoV-2 infection in the UK (AGILE CST-2): a randomised, placebo-controlled, double-blind, phase 2 trial

BACKGROUND

The antiviral drug molnupiravir was licensed for treating at-risk patients with COVID-19 on the basis of data from unvaccinated adults. We aimed to evaluate the safety and virological efficacy of molnupiravir in vaccinated and unvaccinated individuals with COVID-19.

METHODS

This randomised, placebo-controlled, double-blind, phase 2 trial (AGILE CST-2) was done at five National Institute for Health and Care Research sites in the UK. Eligible participants were adult (aged ≥18 years) outpatients with PCR-confirmed, mild-to-moderate SARS-CoV-2 infection who were within 5 days of symptom onset. Using permuted blocks (block size 2 or 4) and stratifying by site, participants were randomly assigned (1:1) to receive either molnupiravir (orally; 800 mg twice daily for 5 days) plus standard of care or matching placebo plus standard of care. The primary outcome was the time from randomisation to SARS-CoV-2 PCR negativity on nasopharyngeal swabs and was analysed by use of a Bayesian Cox proportional hazards model for estimating the probability of a superior virological response (hazard ratio [HR]>1) for molnupiravir versus placebo. Our primary model used a two-point prior based on equal prior probabilities (50%) that the HR was 1·0 or 1·5. We defined a priori that if the probability of a HR of more than 1 was more than 80% molnupiravir would be recommended for further testing. The primary outcome was analysed in the intention-to-treat population and safety was analysed in the safety population, comprising participants who had received at least one dose of allocated treatment. This trial is registered in ClinicalTrials.gov, NCT04746183, and the ISRCTN registry, ISRCTN27106947, and is ongoing.

FINDINGS

Between Nov 18, 2020, and March 16, 2022, 1723 patients were assessed for eligibility, of whom 180 were randomly assigned to receive either molnupiravir (n=90) or placebo (n=90) and were included in the intention-to-treat analysis. 103 (57%) of 180 participants were female and 77 (43%) were male and 90 (50%) participants had received at least one dose of a COVID-19 vaccine. SARS-CoV-2 infections with the delta (B.1.617.2; 72 [40%] of 180), alpha (B.1.1.7; 37 [21%]), omicron (B.1.1.529; 38 [21%]), and EU1 (B.1.177; 28 [16%]) variants were represented. All 180 participants received at least one dose of treatment and four participants discontinued the study (one in the molnupiravir group and three in the placebo group). Participants in the molnupiravir group had a faster median time from randomisation to negative PCR (8 days [95% CI 8-9]) than participants in the placebo group (11 days [10-11]; HR 1·30, 95% credible interval 0·92-1·71; log-rank p=0·074). The probability of molnupiravir being superior to placebo (HR>1) was 75·4%, which was less than our threshold of 80%. 73 (81%) of 90 participants in the molnupiravir group and 68 (76%) of 90 participants in the placebo group had at least one adverse event by day 29. One participant in the molnupiravir group and three participants in the placebo group had an adverse event of a Common Terminology Criteria for Adverse Events grade 3 or higher severity. No participants died (due to any cause) during the trial.

INTERPRETATION

We found molnupiravir to be well tolerated and, although our predefined threshold was not reached, we observed some evidence that molnupiravir has antiviral activity in vaccinated and unvaccinated individuals infected with a broad range of SARS-CoV-2 variants, although this evidence is not conclusive.

FUNDING

Ridgeback Biotherapeutics, the UK National Institute for Health and Care Research, the Medical Research Council, and the Wellcome Trust.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

An Open Label, Adaptive, Phase 1 Trial of High-Dose Oral Nitazoxanide in Healthy Volunteers: An Antiviral Candidate for SARS-CoV-2

Repurposing approved drugs may rapidly establish effective interventions during a public health crisis. This has yielded immunomodulatory treatments for severe coronavirus disease 2019 (COVID-19), but repurposed antivirals have not been successful to date because of redundancy of the target in vivo or suboptimal exposures at studied doses. Nitazoxanide is a US Food and Drug Administration (FDA) approved antiparasitic medicine, that physiologically-based pharmacokinetic (PBPK) modeling has indicated may provide antiviral concentrations across the dosing interval, when repurposed at higher than approved doses. Within the AGILE trial platform (NCT04746183) an open label, adaptive, phase I trial in healthy adult participants was undertaken with high-dose nitazoxanide. Participants received 1,500 mg nitazoxanide orally twice-daily with food for 7 days. Primary outcomes were safety, tolerability, optimum dose, and schedule. Intensive pharmacokinetic (PK) sampling was undertaken day 1 and 5 with minimum concentration (Cmin ) sampling on days 3 and 7. Fourteen healthy participants were enrolled between February 18 and May 11, 2021. All 14 doses were completed by 10 of 14 participants. Nitazoxanide was safe and with no significant adverse events. Moderate gastrointestinal disturbance (loose stools or diarrhea) occurred in 8 participants (57.1%), with urine and sclera discoloration in 12 (85.7%) and 9 (64.3%) participants, respectively, without clinically significant bilirubin elevation. This was self-limiting and resolved upon drug discontinuation. PBPK predictions were confirmed on day 1 but with underprediction at day 5. Median Cmin was above the in vitro target concentration on the first dose and maintained throughout. Nitazoxanide administered at 1,500 mg b.i.d. with food was safe with acceptable tolerability a phase Ib/IIa study is now being initiated in patients with COVID-19.

A Case of Ovarian Dysplasia and a Vaginal Fibroleiomyoma in a Young Golden Retriever

This case demonstrates a unique ovarian congenital anomaly that likely contributed to the development of a rare fibroleiomyoma in the cranial vagina of a young bitch. A 13 month old intact female Golden Retriever presented to the veterinary teaching hospital for urinary incontinence, hematuria, and persistent vaginal discharge. Physical examination revealed a mucopurulent serosanguinous malodorous vulvar discharge, and after further diagnostics was reclassified as persistent estrus. Abdominal palpation and ultrasound revealed uterine thickening and poorly visualized ovaries. The reproductive tract was removed during an ovariohysterectomy, revealing small ovaries and a white anterior vaginal mass. Histopathology revealed dysplastic ovaries with hyperplastic granulosa cells and a benign vaginal fibroleiomyoma. These morphologic changes are consistent with elevated estrogen levels. It was thus concluded that her persistent estrus and the fibroleiomyoma were both secondary to persistent estrogen production by the hyperplastic granulosa cells.

Optimal dose and safety of molnupiravir in patients with early SARS-CoV-2: a Phase I, open-label, dose-escalating, randomized controlled study

OBJECTIVES

AGILE is a Phase Ib/IIa platform for rapidly evaluating COVID-19 treatments. In this trial (NCT04746183) we evaluated the safety and optimal dose of molnupiravir in participants with early symptomatic infection.

METHODS

We undertook a dose-escalating, open-label, randomized-controlled (standard-of-care) Bayesian adaptive Phase I trial at the Royal Liverpool and Broadgreen Clinical Research Facility. Participants (adult outpatients with PCR-confirmed SARS-CoV-2 infection within 5 days of symptom onset) were randomized 2:1 in groups of 6 participants to 300, 600 and 800 mg doses of molnupiravir orally, twice daily for 5 days or control. A dose was judged unsafe if the probability of 30% or greater dose-limiting toxicity (the primary outcome) over controls was 25% or greater. Secondary outcomes included safety, clinical progression, pharmacokinetics and virological responses.

RESULTS

Of 103 participants screened, 18 participants were enrolled between 17 July and 30 October 2020. Molnupiravir was well tolerated at 300, 600 and 800 mg doses with no serious or severe adverse events. Overall, 4 of 4 (100%), 4 of 4 (100%) and 1 of 4 (25%) of the participants receiving 300, 600 and 800 mg molnupiravir, respectively, and 5 of 6 (83%) controls, had at least one adverse event, all of which were mild (≤grade 2). The probability of ≥30% excess toxicity over controls at 800 mg was estimated at 0.9%.

CONCLUSIONS

Molnupiravir was safe and well tolerated; a dose of 800 mg twice daily for 5 days was recommended for Phase II evaluation.

AGILE: a seamless phase I/IIa platform for the rapid evaluation of candidates for COVID-19 treatment: an update to the structured summary of a study protocol for a randomised platform trial letter

BACKGROUND

There is an urgent unmet clinical need for the identification of novel therapeutics for the treatment of COVID-19. A number of COVID-19 late phase trial platforms have been developed to investigate (often repurposed) drugs both in the UK and globally (e.g. RECOVERY led by the University of Oxford and SOLIDARITY led by WHO). There is a pressing need to investigate novel candidates within early phase trial platforms, from which promising candidates can feed into established later phase platforms. AGILE grew from a UK-wide collaboration to undertake early stage clinical evaluation of candidates for SARS-CoV-2 infection to accelerate national and global healthcare interventions.

METHODS/DESIGN

AGILE is a seamless phase I/IIa platform study to establish the optimum dose, determine the activity and safety of each candidate and recommend whether it should be evaluated further. Each candidate is evaluated in its own trial, either as an open label single arm healthy volunteer study or in patients, randomising between candidate and control usually in a 2:1 allocation in favour of the candidate. Each dose is assessed sequentially for safety usually in cohorts of 6 patients. Once a phase II dose has been identified, efficacy is assessed by seamlessly expanding into a larger cohort. AGILE is completely flexible in that the core design in the master protocol can be adapted for each candidate based on prior knowledge of the candidate (i.e. population, primary endpoint and sample size can be amended). This information is detailed in each candidate specific trial protocol of the master protocol.

DISCUSSION

Few approved treatments for COVID-19 are available such as dexamethasone, remdesivir and tocilizumab in hospitalised patients. The AGILE platform aims to rapidly identify new efficacious and safe treatments to help end the current global COVID-19 pandemic. We currently have three candidate specific trials within this platform study that are open to recruitment.

TRIAL REGISTRATION

EudraCT Number: 2020-001860-27 14 March 2020 ClinicalTrials.gov Identifier: NCT04746183  19 February 2021 ISRCTN reference: 27106947.

Histopathological and immunohistochemical findings of primary and metastatic medullary thyroid carcinoma in a young dog

This report describes the gross, histological, and immunohistochemical features of medullary thyroid carcinoma (MTC) with pulmonary metastases in a young dog. Sheets of pleomorphic cells supported by fibrous stroma characterized the primary mass, while metastatic nodules had a neuroendocrine pattern. Despite differing histologic features, all masses showed marked immunoreactivity against calcitonin and multiple neuroendocrine markers consistent with MTC. Although MTC is a well-recognized entity, it may be difficult to distinguish this mass from other thyroid neoplasms, necessitating immunohistochemical characterization.

6 GENE EXPRESSION ANALYSIS OF IN VIVO- AND IN VITRO-MATURED PORCINE METAPHASE II OOCYTES

In vitro-matured (IVM) oocytes lack the same developmental competence as oocytes that are matured in vivo (IVV), yet no compelling explanation for this discrepancy has been provided at the molecular level. The aim of this study was to quantify and compare mRNA levels in IVM and IVV oocytes for genes from a wide variety of functional gene categories, including RNA degradation, pluripotency, epigenome modification, oocyte-specific, and apoptosis. Quantitative real-time PCR (qPCR) was used to evaluate the relative gene expression levels of 70 genes in each of 33 individual IVM oocytes from 4 different collection days and 29 individual IVV oocytes from 4 different donor animals. The qPCR data were analysed using ANOVA and significance was assigned at P < 0.05. After a multiple testing correction was applied, relative transcript abundances for 32 of the 70 genes tested were found to be significantly different (q < 0.05) between the IVM and IVV oocytes. Of these significantly different genes, 23 were higher in the IVM oocytes and only 9 were higher in the IVV oocytes. The 32 significantly differentially expressed genes were then evaluated in relation to their corresponding functional gene categories. Of particular interest, transcripts for 7/14 RNA degradation-related genes (CNOT3, DCP1A, DDX6, LSM1, PABPN1, PABPN1L, PARN) and 3/9 oocyte specific genes (BMP15, YBX2, H1FOO) were significantly more abundant in the IVM oocytes. In contrast, transcripts for 4/8 epigenetic related transcripts (ASH2l, DNMT1, EHMT2, EZH2), 2/2 apoptosis related genes (BCL2, XIAP), and 1/4 pluripotency factors (LIN28) were significantly more abundant in the IVV oocytes. Gene set enrichment analysis confirmed that, within the context of this experimental design, RNA degradation and chromatin remodelling pathways are significantly perturbed in IVM oocytes. We conclude that in vitro maturation has profound effects on transcript populations of metaphase-II oocytes, with most transcripts being higher in IVM oocytes. We expect that this data will lead to a better understanding of how we can improve the quality of oocytes that are matured in vitro as well as provide information to help to identify markers that could be indicative of oocyte quality.

RNA interference in parasitic helminths: current situation, potential pitfalls and future prospects

RNA interference (RNAi) has become an invaluable tool for the functional analysis of genes in a wide variety of organisms including the free-living nematode Caenorhabditis elegans. Recently, attempts have been made to apply this technology to parasitic helminths of animals and plants with variable success. Gene knockdown has been reported for Schistosoma mansoni by soaking or electroporating different life-stages in dsRNA. Similar approaches have been tested on parasitic nematodes which clearly showed that, under certain conditions, it was possible to interfere with gene expression. However, despite these successes, the current utility of this technology in parasite research is questionable. First, problems have arisen with the specificity of RNAi. Treatment of the parasites with dsRNA resulted, in many cases, in non-specific effects. Second, the current RNAi methods have a limited efficiency and effects are sometimes difficult to reproduce. This was especially the case in strongylid parasites where only a small number of genes were susceptible to RNAi-mediated gene knockdown. The future application of RNAi in parasite functional genomics will greatly depend on how we can overcome these difficulties. Optimization of the dsRNA delivery methods and in vitro culture conditions will be the major challenges.

Prospects for the future: is there a role for virally vectored immunocontraception in vertebrate pest management?

Virally vectored immunocontraception (VVIC) has been studied and promoted as an alternative to lethal methods for vertebrate pest control in Australia and New Zealand. Virally vectored immunocontraception offers a potentially humane and species-specific control method with potential for a good benefit–cost outcome, but its applicability for broad-scale management remains unknown. We present case studies for the house mouse, European rabbit, red fox and common brushtail possum and describe the current status of research into the use of VVIC as a broad-scale pest-management tool. All case studies indicated that there are significant problems with delivery and efficacy. The current state of development suggests that VVIC is not presently a viable alternative for the management of these vertebrate pests, and it is highly unlikely that this will change in the foreseeable future. An absence of benefit–cost data also hinders decision-making, and until benefit–cost data become available it will not be clear if there are short- or long-term benefits resulting from the use of VVIC for broad-scale pest management.

Accelerated re-epithelialization in beta3-integrin-deficient- mice is associated with enhanced TGF-beta1 signaling

The upregulation of TGF-beta1 and integrin expression during wound healing has implicated these molecules in this process, but their precise regulation and roles remain unclear. Here we report that, notably, mice lacking beta(3)-integrins show enhanced wound healing with re-epithelialization complete several days earlier than in wild-type mice. We show that this effect is the result of an increase in TGF-beta1 and enhanced dermal fibroblast infiltration into wounds of beta(3)-null mice. Specifically, beta(3)-integrin deficiency is associated with elevated TGF-beta receptor I and receptor II expression, reduced Smad3 levels, sustained Smad2 and Smad4 nuclear localization and enhanced TGF-beta1-mediated dermal fibroblast migration. These data indicate that alpha(v)beta(3)-integrin can suppress TGF-beta1-mediated signaling, thereby controlling the rate of wound healing, and highlight a new mechanism for TGF-beta1 regulation by beta(3)-integrins.

New algorithms for multi-class cancer diagnosis using tumor gene expression signatures

MOTIVATION

The increasing use of DNA microarray-based tumor gene expression profiles for cancer diagnosis requires mathematical methods with high accuracy for solving clustering, feature selection and classification problems of gene expression data.

RESULTS

New algorithms are developed for solving clustering, feature selection and classification problems of gene expression data. The clustering algorithm is based on optimization techniques and allows the calculation of clusters step-by-step. This approach allows us to find as many clusters as a data set contains with respect to some tolerance. Feature selection is crucial for a gene expression database. Our feature selection algorithm is based on calculating overlaps of different genes. The database used, contains over 16 000 genes and this number is considerably reduced by feature selection. We propose a classification algorithm where each tissue sample is considered as the center of a cluster which is a ball. The results of numerical experiments confirm that the classification algorithm in combination with the feature selection algorithm perform slightly better than the published results for multi-class classifiers based on support vector machines for this data set.

AVAILABILITY

Available on request from the authors.

Evaluation of the harmonic scalpel for laparoscopic bilateral ovariectomy in standing horses

OBJECTIVE

To evaluate use of the Harmonic Scalpel (Ethicon Endo-Surgery Inc., Cincinnati, OH) for performing laparoscopic bilateral ovariectomy in standing horses.

STUDY DESIGN

Experimental study.

ANIMALS

Eight mares aged 2-20 years and weighing 410-540 kg.

METHODS

Standing laparoscopic bilateral ovariectomy was performed in 8 mares with normal reproductive tract anatomy. The Harmonic Scalpel (an ultrasonically activated instrument) was used to simultaneously transect and obtain hemostasis of the ovarian pedicle. Necropsy was performed on 4 mares 3 days after surgery and 4 mares 30 days after surgery. Gross and histopathologic evaluation of the ovarian pedicles was performed to characterize tissue reaction.

RESULTS

Complete hemostasis of the ovarian pedicles was obtained in all mares. Median transection time for the ovarian pedicle was 28 minutes. Postoperative complications included transient fever, moderate subcutaneous emphysema, and incisional seroma formation. On necropsy examination, there were no signs of generalized peritonitis, postoperative hemorrhage, or adhesion formation. Mild to moderate acute inflammation and scar formation with moderate chronic inflammation at the ovarian pedicle was found at 3 and 30 days. Median depth of coagulation necrosis at 3 days was 2.87 mm.

CONCLUSIONS

The Harmonic Scalpel appears to provide reliable hemostasis of the ovarian pedicle during elective laparoscopic ovariectomy in horses. Clinical Relevance-The Harmonic Scalpel represents a safe alternative to other methods of hemostasis during elective laparoscopic ovariectomy in horses.

Emergency ambulances on the public highway linked with inconvenience and potential danger to road users

OBJECTIVES

The main aim was to survey interactions between the public highway users and emergency ambulances using lights and sirens. The objectives were to identify negative and positive experiences, and to assess the frequency and consequences of these events.

METHODS

Because of a poor response from a random postal pilot, a quota sample of 200 was adopted with a response of 65%. This provided data on demographics, details of previous interactions, and possible third party effects. Participant perception of psychological stress in negative interactions was also recorded. Possible links between the recorded interactions were assessed using the chi(2) tests of association.

RESULTS

The passage of an emergency ambulance using lights and sirens caused the public to move from their chosen position in most cases (61%). Horns or sirens were used frequently (86%), but they were not always applied in unison with the warning lights. A significant association was found between the satisfactory handling of events by the ambulance crews and the use of audible warning devices (p<0.001). Twenty per cent of avoidance manoeuvres necessitated reversing, which was associated with a third party affect (p<0.005). Roughly one third of the participants found interactions stressful and felt that the events could have been avoided. Most public road users (91%) believed that they acted in a controlled manner.

CONCLUSIONS

The findings suggest that most participants had interacted with the emergency ambulances in a positive manner, while a smaller but significant fraction of the public road users found the interactions difficult to handle. A third party effect was identified in avoidance manoeuvres. Further longitudal research with random sampling is recommended.

The effectiveness of benzimidazole derivatives for the treatment and prevention of histomonosis (blackhead) in turkeys

The benzimidazole derivatives, albendazole and fenbendazole were evaluated for their effectiveness in the treatment and prevention of histomonosis (blackhead) in turkeys. Histomonosis was produced in 5 week-old birds by placing them on broiler breeder litter known to be contaminated with Heterakis gallinae ova and the protozoan Histomonas meleagridis. In the first trial, at the onset of confirmed clinical disease, birds were treated orally with metronidazole, a compound known to be effective against Histomonas. Those receiving metronidazole had significantly greater mean body weight gains during the treatment period and the 2 weeks following treatment than untreated controls. Treated birds also had significantly lower caecal and liver lesion scores. These findings served to validate the method of disease reproduction and establish its suitability for testing the benzimidazoles. Similar trials were conducted to determine the therapeutic value of albendazole at 100.0 mg/kg of body weight and fenbendazole at 10.0 mg/kg body weight, administered orally twice a day for 5 consecutive days. Under these conditions, both drugs were found to be ineffective as treatments. A final trial was conducted to assess the prophylactic value of albendazole and fenbendazole administration. At the time of placement on contaminated litter, birds were medicated as previously described with the exception that treatment was continued for 14 consecutive days, the approximate incubation period for histomonosis. The trial was terminated on the 16th day. In the case of both albendazole and fenbendazole, treatment was associated with a significant increase in mean body weight gain and lower caecal and liver lesion scores. It is believed that the observed prophylactic effect may be attributed to the destruction of the transport vector e.g., Heterakis larvae, or to direct killing of the flagellated form of Histomonas which is normally found in the caecal lumen and is considered to be more sensitive to chemotherapeutic agents than the amoeboid form found in tissues.

Phylogenetic relationships of the Raphidophyceae and Xanthophyceae as inferred from nucleotide sequences of the 18S ribosomal RNA gene

Some earlier studies suggested an evolutionary relationship between the Raphidophyceae (chloromonads) and Xanthophyceae (yellow-green algae), whereas other studies suggested relationships with different algal classes or the &ouml;omycete fungi. To evaluate the relationships, we determined the complete nucleotide sequences of the 18S ribosomal RNA gene from the raphidophytes Vacuolaria virescens, Chattonella subsalsa, and Heterosigma carterae, and the xanthophytes Vaucheria bursata, Botrydium stoloniferum, Botrydiopsis intercedens, and Xanthonema debile. The results showed that the Xanthophyceae were most closely related to the Phaeophyceae. A cladistic analysis of combined data sets (nucleotide sequences, ultrastructure, and pigments) suggested the Raphidophyceae are the sister taxon to the Phaeophyceae-Xanthophyceae clade, but the bootstrap value was low (40%). The raphidophyte genera were united with high (100%) bootstrap values, supporting a hypothesis based upon ultrastructural features that marine and freshwater raphidophytes form a monophyletic group. We examined the relationship between Vaucheria, a siphoneous xanthophyte alga, and the &ouml;omycetes, and we confirmed that Vaucheria is a member of the class Xanthophyceae. Partial nucleotide sequences of the 18S rRNA gene from eight xanthophytes (including Bumillariopsis filiformis, Heterococcus caespitiosus, and Mischococcus sphaerocephalus) produce a phylogeny that is not congruent with the current morphology-based classification scheme.

Extracellular pH affects regulation of the pcbAB gene in Penicillium chrysogenum

The effect of extracellular pH and dissolved oxygen on regulation of the pcbAB gene in P. chrysogenum was examined, using Northern analysis and a reporter gene fusion. It was found that ambient pH markedly affected levels of pcbAB mRNA whereas maintenance of dissolved oxygen concentration above 10% had no detectable effect. The presence of a DNA-binding protein, which binds upstream of the pcbAB translational start codon, was also related to ambient pH. In all fermentations, pcbAB mRNA was most abundant at around the late exponential/early stationary phase of a culture.

Can foxes be controlled by reducing their fertility?

A model based on data from research in New South Wales conducted by the Cooperative Research Centre for the Biological Control of Vertebrate Pest Populations suggests that the effectiveness of fertility control in reducing the abundance of foxes (Vulpes vulpes) can be strongly influenced by environmental variability. The model includes age-specific recruitment and survival as functions of resources indexed by rainfall. It is assumed that fertility control will affect only female foxes and that the use of a baiting regime to deliver a contraceptive agent will result in fixed proportional changes in pregnancy rates. By comparing the variability in the rate of increase of treated and untreated fox populations, the model predicts that: (i) frequent baiting, every one or two years, will be more effective than applications of baits at longer time intervals; (ii) the abundance of foxes will decline more rapidly, with higher levels of fertility control; (iii) infertility which lasts for only one breeding season is less effective than permanent sterility which allows for accumulation of sterile animals in the population; and (iv) highly variable results are likely to be the outcome of low-frequency baiting with an agent that produces only temporary infertility.

Factors affecting DNA-binding proteins and pcbC transcript levels in Penicillium chrysogenum

Proteins extracted from Penicillium chrysogenum grown in either complex or defined medium were used in electromobility shift assays. With a probe DNA covering the region -10 to -132 relative to the pcbC translation start codon, four protein/DNA complexes (designated A-D) were reproducibly observed. Two of the four DNA/protein complexes routinely detected in extracts from liquid cultures (A and B) were also detectable with protein extracts from P. chrysogenum spores. Generally, with proteins from liquid cultures, there was a correlation between increased levels of the complexes and increased levels of the pcbC transcript. In addition, the detectable levels of the complexes and the pcbC transcript showed some relationship to the extracellular pH of the medium. In defined medium, with glucose as the carbon source, the pcbC transcript was not detectable in extracts from the wild-type strain at any time, whereas with the high penicillin-producing strain P-2, a pcbC transcript was detected. In complex medium, the pcbC transcript was detectable during the exponential phase of cultures of the wild-type or P-2, even when glucose levels were as high as 2.5% (w/v).

Movements and Home Ranges of Feral Pigs (Sus Scrofa) in Kosciusko National Park, New South Wales

The movements of a subalpine population of feral pigs were examined at Kosciusko National Park in southeastern New South Wales. Sufficient data were collected to estimate the home-range area of 20 pigs on the basis of 782 telemetry and trap locations. Mean (+/- s.d.) home-range size (minimum convex polygon method) for males (35.0 t 22.2 km*2) was significantly greater than that for females (1 1.1 +/- 5.2 km*2). Use of capture-recapture distances to estimate home-range size was considered inappropriate. A test for nomadism suggests that, although home ranges of pigs in this environment were larger than those reported for other pigs in Australia, the pigs were essentially sedentary. Management implications for this population are discussed.

Beyond retention: National Health Service Corps participation and subsequent practice locations of a cohort of rural family physicians

BACKGROUND

This report addresses the long-term career paths and retrospective impressions of a cohort of family physicians who served in rural National Health Service Corps (NHSC) sites in return for having received medical school scholarships during the early 1980s.

METHODS

We surveyed all physicians who graduated from medical school between 1980 and 1983, received NHSC scholarships, completed family medicine residencies, and served in rural areas. Two hundred fifty-eight physicians responded to our survey with complete information, 76 percent of the members of the cohort who could be located and met the study criteria.

RESULTS

In 1994 one quarter of the respondents were still practicing in the county to which they had been assigned by the NHSC, an average of 6.1 years after the end of their obligation. Another 27 percent were still in rural practice. Of the entire group, less than 40 percent were in traditional urban private or managed care settings.

CONCLUSIONS

Although only one quarter of NHSC assignees remain long term in their original assignment counties, they provide a large (and growing) amount of nonobligated service to those areas. Of those who leave, many remain in rural practice or work in community-oriented urban practices.

Thymic nurse cell rescue of early CD4+CD8+ thymocytes from apoptosis

We have now developed temperature sensitive lines of thymic nurse cells (TNCs), using the SV40 viral mutant tsA58, that maintain the ability to selectively internalize a subpopulation of alpha beta TCR+CD4+CD8+ thymocytes in vitro. One line, tsTNC-1, was shown to be able to rescue a subset of CD4+CD8+ thymocytes from programmed cell death at 32 degrees C, the temperature at which binding and internalization were detected. Rescue was significantly diminished at 38 degrees C, the temperature at which thymocyte binding was not observed. The rescued population of thymocytes showed a reduced level of apoptosis as measured by the DNA fragmentation assay. TNC rescue resulted in a shift of CD4+CD8+ thymocytes from immature TCRlow PNArhigh cells to the more mature TCRint PNArlow phenotype but no changes in cell surface levels of HSA nor CD69 were detected. The rescue activity of tsTNC-1 cells at 32 degrees C was significantly reduced with the addition of antibodies to either class I or class II MHC antigens. These results suggest that we have established TNC lines, using the SV40 viral mutant tsA58, that have the ability to rescue a subset of the TNC interactive thymocyte population from programmed cell death. The thymocyte population rescued by TNCs matures to a phenotype within the double positive stage of development that is indicative of positive selection.

Detection of a protein which binds specifically to the upstream region of the pcbAB gene in Penicillium chrysogenum

The upstream region of the pcbAB gene from Penicillium chrysogenum was screened for protein-binding sites using an electromobility shift assay. A specific protein/DNA interaction was detected within a fragment covering the region -387 to -242 relative to the pcbAB translational start codon. The appearance of this protein and pcbAB mRNA in culture extracts occurred at the same time point in fermentations, suggesting that the protein might be a transcription activator. The putative upstream activating sequence was located more precisely using cross-competition assays. These indicated the involvement of the 7-bp motif TGCCAAG in the binding of the protein.

Structural analysis of the human nov proto-oncogene and expression in Wilms tumor

We have cloned and sequenced the nov gene (novH) which is the homolog of the chicken nov proto-oncogene overexpressed in avian nephroblastomas. The novH gene is highly conserved and encodes a putative IGF-binding protein similar to that of chicken. We report that relative to autologous normal kidney expression of novH is elevated in Wilms tumors containing predominantly stromal elements and is inversely correlated in these tumors to the expression of WT1. Our results suggest that the regulation of IGFII expression by WT1 and increase of novH in Wilms tumors might be interrelated and represent a key element in tumor development in human.

Use of INT to determine the respiratory activity of immobilised and free Penicillium chrysogenum

The specific oxygen uptake rates (OUR) of kappa-carrageenan-immobilised and free cell cultures of Penicillium chrysogenum were determined using an oxygen electrode in a closed chamber. This was compared with the respiratory activity determined by the extent of staining with iodo-nitrophenyl tetrazolium chloride (INT). The degree of INT staining correlated with the OUR; an increase in INT deposition corresponding to an increase in the measured OUR. The INT staining technique could therefore be used to determine cell respiratory activity. In this way a profile of fungal cell activity throughout immobilised cell aggregates and free cell pellets was determined. In both types of cell culture, after the initial growth period only the peripheral biomass was observed to be active.

The Demography of Feral Pigs (Sus Scrofa) in Kosciusko National Park, New South Wales

The demography of a sub-alpine population of feral pigs was examined at Kosciusko National Park in south-eastern New South Wales. Reproductive data and age structures indicated a seasonal pattern of breeding, most births occurring in summer and autumn. It is proposed that a decreasing availability of high protein food in the autumn and winter months caused reduced rates of conception. Sows produced 0.84 litters per year with postnatal mortality as high as 85%. The population appeared relatively stable at a density of 1.6 pigs kg-2. Hunting, although illegal in a national park, removed 4.4-15.4% of pigs each year. The overall health and body condition of pigs was good, with no evidence of heavy parasitic burdens or disease. Age-specific body weight and body length in this study were greater than those reported for pigs in semi-arid wester New South Wales.

Physiological studies related to the immobilization of Penicillium chrysogenum and penicillin production

Using the production of penicillin by Penicillium chrysogenum as a model system, certain physiological aspects of immobilized and free cell cultures were compared. Reducing the immobilized viable spore loading (from 4 x 10(4) to 2 x 10(3) spores ml-1 gel) and initial bead diameter (from 3.5-4.0 to 1.5-2.0 mm) gave rise to an increase in the penicillin titer from 0.2 to 1.2 g l-1. Using these conditions in immobilized cell culture the growth phase was prolonged and the duration of expression of the isopenicillin N synthase gene (pcbC) was significantly extended when compared with free cell culture (150 h as opposed to 100 h). During the period of maximum penicillin production, different penicillin biosynthetic intermediates accumulated in the broth of free and immobilized cell cultures, reflecting a fundamental difference in cell physiology. Although the maximum specific productivity of penicillin production was reduced by immobilization, the average specific productivity increased when compared to free cell fermentation.

A Comparison of Three Ageing Techniques for Feral Pigs From Subalpine and Semi-Arid Habitats

Three ageing techniques were tested on samples of wild-caught feral pigs from subalpine (n =35) and semi-arid (n =64) areas in eastern Australia, and on a sample of known-age captive feral pigs reared from stock from semi-arid areas (n =15). Techniques employed were based on morphometric relationships, patterns of tooth eruption and wear, and counts of cementum lines in permanent incisors. Cyclic seasonal conditions led to apparently annular cementum line deposition for pigs from the subalpine area. In contrast, stochastic variation in seasonal conditions led to irregular cementum line deposition in pigs from the semi-arid area and captive-reared pigs of semi-arid stock. On the assumption that cementum lines are annular in pigs from the subalpine site, patterns of tooth eruption and wear and morphometrics returned reasonably accurate age estimates, the former being more precise. Patterns of tooth eruption and wear returned reasonably accurate age estimates for known-age captivereared pigs, whereas morphometrics gave increasing underestimates of age for progressively older pigs. On the assumption that patterns of tooth eruption and wear return similarly accurate age estimates for wild pigs from the semi-arid area, morphometrics again underestimated true age. A correction to the morphometric technique to improve its accuracy for semi-arid areas is given.

Observations on the effectiveness of shooting feral pigs from helicopters

The use of helicopters for the shooting of feral pigs in western New South Wales has become increasingly popular and widespread. Studies were conducted to evaluate the effectiveness of this practice in terms of population reduction, rate of population recovery and cost. The study site was an area of 120 km*2 on the southern edge of the Macquarie Marshes. Estimated population reductions, calculated by the index-removal method, over two consecutive years were 80 and 65%. The associated rate of increase (r) in the 12 months following the first population reduction was 1.34, which is equivalent to a recovery of 77% in numbers. Results and levels of control inputs were collated for an additional consecutive year and compared with other studies. Management implications from this study are also considered.

Factors Affecting Bait Uptake and Trapping Success for Feral Pigs (Sus Scrofa) in Kosciusko National Park

An evaluation of the rate and extent of population reduction that can be achieved by trapping feral pigs was conducted in a subalpine area of Kosciusko National Park in south-eastern New South Wales. Movements of pigs during the programme were monitored by radio-telemetry. In total, 142 pigs, including 12-17 (71%) previously fitted with transmitters and known to be still on the study site, were captured over 330 trap-nights at a cost of $A104 per pig. A model fitted to the change in percentage of bait stations eaten per day relative to the cumulative number of pigs caught estimated a population reduction of 62% of animals exposed to traps and only 28% of the entire population. Determinants of trap success are discussed. During the trapping evaluation and in 2 preceding seasons, factors that influenced the rate at which bait stations were found and eaten were also examined. Both the locality characteristics of bait stations and the time of year were found to have significant effects on this rate.

Iophenoxic Acid as a Quantitative Bait Marker for Foxes

The potential of iophenoxic acid as a quantitative bait marker for red foxes was investigated. Groups of adult foxes were administered doses of either 20, 40 or 60mg, representing one, two or three baits. Baseline concentrations of plasma iodine were compared with samples collected one, three, six and ten weeks after exposure. Plasma iodine levels were elevated by 7-18 times base-line estimates after six weeks and had returned to pre-treatment levels in approximately half the foxes by ten weeks. Application of regression analyses provided a relationship that could be used to estimate the number of baits eaten from post-exposure plasma iodine levels and the number of weeks after bait was offered.