Search

T. Evans in [4] introduced a concept generalizing the associative law for groups. Certain very restricted cases of this generalization had occurred, somewhat as side results, in the considerations of A. K. Suškevič [7], D. C. Murdoch [5], [6], and R. H. Bruck [2] associated with quasigroups which obey theorems generalizing certain results in group theory.In this paper we consider quasigroups obeying an instance of Evans' generalization. We show two means of constructing such quasigroups, and we demonstrate these constructions with several examples. The principal result of this paper is a theorem which reveals a peculiar trait of quasigroups obeying an instance of the generalized associative law we are considering. Such a quasigroup obeys a law expressed with permutations in which the nontrivial permutations involved either are both automorphisms of the quasigroup or else both fail to distribute over any product from the quasigroup.

Using pacemakers implanted in canines with surgically induced atrioventricular blocks, the effects of the microwave-oven frequencies (915 and 2450 MHz) and two radar frequencies (2810 and 3050 MHz) were evaluated. Quantitative evaluation of these fields with respect to complete inhibition of pacemakers can be made. A narrow zone of inhibition during some exposures-a ``window'' effect-not previously described is reported. The following field parameters would be regarded as potential situations for complete pacemaker inhibition: 1) 915-MHz-fields continuous- and sine-wave modulation at 120 Hz in field strengths over 75 V/m, and 2) fields at either 2810 or 3050 MHz pulsed at a rate of 40 pulses per second (pps) or less with a field strength greater than 250 V/m.

The Royal Navy operates a fleet of complex modern warships and submarines each comprising a system of systems often in harsh and potentially volatile environments. The maintenance of surface vessels is primarily undertaken by Babcock and BAe Systems in an alliance with the Ministry of Defence. The Ministry of Defence system engineering lifecycle is known as CADMID, this details the six phases of a projects’ lifecycle from Concept through to Disposal. The “In-Service” phase of a naval vessel will typically constitute 70% of the artefact's through-life cost. During the “In-Service” phase the number and involvement of stakeholders will vary as the vessel cycles through Tasking, Upkeep and Regeneration. The paper considers the key stakeholders and their participation in each cyclical mode. Information to be exploited will be subject to two discrete drivers, firstly the information available for exploitation as a consequence the vessels’ current cyclical mode, secondly, the characteristics of the information source.

A new spiral bacterium, distinct from Campylobacter pylori, was found in the gastric mucosa of six patients with gastrointestinal symptoms. All patients had chronic active type B gastritis and four had oesophagitis. Culture and microscopy for C pylori infection was negative. These unculturable spiral organisms were probably an incidental finding in patients presenting for upper gastrointestinal endoscopy, but it is not possible to say from this small series whether these organisms cause chronic active gastritis. The organism is helical, 3.5-7.5 microns long and 0.9 micron in diameter with truncated ends flattened at the tips, and up to 12 sheathed flagella 28 nm in diameter at each pole. It is proposed that this spiral bacterium should be called "Gastrospirillum hominis Gen.nov., Sp.nov."

The principle of abstraction, of separating a concept from a particular implementation of that concept, is gaining increasingly widespread use in programming and problem solving, and in teaching these subjects. A method of teaching the abstract concept of recursion, independent of its implementation, is presented.

Two groups of lambs raised free of sporozoan infection were inoculated with Sarcocystis tenella sporocysts and compared with controls. Lambs from Group 1 were inoculated with 5000 sporocysts and those in Group 2 were given 20 000. Transient increases in rectal temperatures occurred between 23 and 39 days post-inoculation (dpi), although the lambs appeared normal and retained their appetites. Packed cell volumes (PCV) of lambs given 20 000 sporocysts decreased dramatically from 28 to 38 dpi after which they slowly returned to near pre-inoculation levels by 99 dpi. The anaemia was normocytic/ normochromic. White cell counts (WCC) rose in infected lambs from 49 dpi, reflecting pricipally an increase in lymphocyte numbers. Plasma albumin of Group 2 decreased at 28 dpi and remained depressed untile the experiment was terminated at 99 dpi. Plasma globulin of infected groups increased from 31 (Group 2) and 35 dpi (Group 1). Plasma alkaline phosphatase (ALP) of Group 2 decreased from 28 dpi and remaind depressed to 99 dpi. Lactate dehyrogenase (LDH) of Group 2 was elevated at 24 and 28 dpi and from 42 to 78 dpi, while aspartate aminotransferase (AST) of the same group was elevated from 45 to 66 spi. Creatine kinase (CK) of Group 2 was elevated from 52 to 71 dpi.

The venorelaxant effect of atrial natriuretic factor in man was studied using the dorsal hand vein technique. Infusion of met-ANF to preconstricted veins at doses up to 240 ng min-1 in 11 healthy male subjects caused only minimal venorelaxation. Atrial natriuretic factor is unlikely to have a significant venorelaxant effect at physiological doses in man.

Three years after the start of an experiment to assess the merits of thiabendazole (TBZ) treatment of trichostrongylid parasites in weaner sheep, field isolates of Ostertagia spp and Trichostrongylus spp were made from weaner sheep treated under one of three treatment schemes. Treatment frequencies were "nil", "planned" (5 or 6/year) and "regular" (every 3 weeks). In addition an isolate was taken from a group of "tracer" sheep drenched with TBZ every 10 days. Resistance to TBZ was assessed using an in vitro egg hatch assay, pre- and post-treatment faecal egg counts and a controlled anthelmintic efficiency test. Pre- and post-treatment egg counts revealed the presence of TBZ-resistance in field isolates of mixed species. Egg hatch assays indicated a level of resistance for Ostertagia spp which was proportional to the frequency of TBZ treatment. The "planned", "regular" and "tracer" strains of Ostertagia spp had resistance ratios for eggs of 4, 13 and 15 respectively when compared to the "nil" strain. In the anthelmintic efficiency assay treatment with 44 mg kg-1 and 88 mg kg-1 of TBZ removed 82 and 96% respectively of the total Ostertagia burden (adults and larvae) from the "nil" strain and 30 and 75% respectively from the "planned" strain. The same dose rates against the "regular" and "tracer" strains and additional rates of 132 or 176 mg kg-1 against the "tracer" strain failed to reduce the Ostertagia burden significantly. Intestinal Trichostrongylus spp from all isolates were fully susceptible to TBZ at 44 mg kg-1. Levamisole at 7.0 mg kg-1 was highly effective (99% reduction) against the "tracer" strain of Ostertagia.

SUMMARY The confirmation of a cat-sheep transmission for visible sarcocysts was achieved in specific pathogen free (SPF) animals by completing sheep-cat-sheep-cat passages during 1977–79. The study used 22 laboratory cats and 15 specially bred sheep. Experimental sheep were dosed with sporocysts recovered from cats fed visible sarcocysts. “Giant” or “fat” form of macroscopic sarcocysts commonly found on the oesophagus were first demonstrated in the SPF sheep at 17 months after dosing. The sarcocysts from these sheep were infective to cats. Thus, the cycle of transmission for cat-borne ovine sacosporidiosis was completed. Grazing sheep in some situations develop visible cysts earlier, around one year of age, hence it is considered that the infections of experimental sheep in SPF conditions may not reflect all the circumstances leading to natural infection.

We have developed over the past few years new linear filtering methods for images which incorporate the use of properties of human vision in design. These methods apply to noise removal, image enhancement and image restoration. One interesting extension of our work is to the use of the anisotropy of vision to achieve better visual quality. In this paper we propose combining several of these processing tasks at once, by taking advantage of visual perception and of the image content information that can be estimated directly from the image. We present a brief overview of the image filtering techniques using properties of vision that we have developed and discuss the basis on which several processing tasks can be combined for the same image. We discuss briefly the approach taken to the implementation of such multistep algorithms on dedicated pipeline image processors.

Gas within the retroperitoneum is usually a sign of serious gastrointestinal or urinary tract pathology. Most commonly, it results from bowel perforation secondary to inflammatory or ulcerative disease, blunt or penetrating trauma or to iatrogenic manipulation such as double-contrast barium enema or colonoscopy (Lezak & Goldhammer, 1974; Peterson et al, 1982). Retroperitoneal gas may also result from pancreatitis complicated by bacterial infection or infection in the perirenal space (Meyers, 1974). It has also been reported as a complication of mechanical ventilation when, following alveolar rupture, air tracks into the mediastinum and then passes retrocrurally into the retroperitoneum (Powner et al, 1976). We wish to report a case of pneumoretroperitoneum demonstrated by computed tomography (CT) which we believe to be the first case reported as a complication of iliac crest trephine.

Gastric mucosal concentrations of erythromycin, amoxycillin, ampicillin and ciprofloxacin were determined in patients at upper gastrointestinal endoscopy 38-480 min after a 500 mg dose of erythromycin ethyl succinate, erythromycin stearate, amoxycillin, pivampicillin or ciprofloxacin. All the agents attained concentrations greater than the MIC 90 for Campylobacter pylori. The macrolides attained the lowest concentrations. There was no significant difference between concentrations attained with erythromycin ethyl succinate and stearate. High concentrations were attained by amoxycillin (range 14.6-322 mg/kg) and pivampicillin (range 47.5-209 mg/kg). Ciprofloxacin attained very high concentrations (range 35-1762 mg/kg); inhibitory concentrations 35 mg/kg) were still present at 6 h after the dose. Ciprofloxacin and erythromycin are ineffective in vivo despite these high gastric mucosal concentrations. Penetration into the gastric mucus and crypts where C. pylori is found will be determined by physicochemical properties of the antimicrobials, such as pKa, stability, activity over a wide range of pH, and lipid solubility.

The design of underground cable systems requires knowledge of the thermal environment in which the cables are to be installed. Many papers have been written over the years which describe methods for measuring the thermal properties of soils, and two papers in this volume (Steinmanis, 1981; Boggs, 1981) describe the most recent improvements in laboratory and field measurements. Although such measurements provide designers with useful information, the strong moisture dependence of soil thermal properties coupled with significant seasonal and climatic fluctuations makes reliance on limited spot measurements questionable for cable design. This article describes an approach which can be used in addition to laboratory and field measurements to provide statistically based estimates of soil thermal properties which include climatic and seasonal effects.

The species of trichostrongyloid nematodes present in 376 sheep from different agricultural regions of the state of South Australia were determined. Parasites encountered in the abomasum were Teladorsagia circumcincta, T. trifurcata, T. davtiani, Camelostrongylus mentulatus, Haemonchus contortus and Trichostrongylus axei. T. circumcincta was the species most commonly encountered, but C. mentulatus was widespread in arid areas. H. contortus was present in a small number of sheep only, mainly in southern areas. In the small intestine, Trichostrongylus vitrinus predominated in the wetter, southern districts, and T. rugatus in dry, northern areas. T. colubriformis was common, but was rarely dominant. T. probolurus was found in one sheep. Nematodirus filicollis was restricted to wetter, southern areas, while N. spathiger and N. abnormalis were widespread and predominated in dry areas. N. helvetianus was found once. Cooperia species were uncommon; species encountered were C. oncophora, C. surnabada and C. pectinata.

Background Thrombolytic treatment for acute ischaemic stroke improves prognosis, although there is a risk of bleeding complications leading to early death/severe disability. Benefit from thrombolysis is time dependent and treatment must be administered within 4.5 hours from onset of symptoms, which presents unique challenges for development of tools to support decision making and patient understanding about treatment. Our aim was to develop a decision aid to support patient-specific clinical decision-making about thrombolysis for acute ischaemic stroke, and clinical communication of personalised information on benefits/risks of thrombolysis by clinicians to patients/relatives. Methods Using mixed methods we developed a COMPuterised decision Aid for Stroke thrombolysiS (COMPASS) in an iterative staged process (review of available tools; a decision analytic model; interactive group workshops with clinicians and patients/relatives; and prototype usability testing). We then tested the tool in simulated situations with final testing in real life stroke thrombolysis decisions in hospitals. Clinicians used COMPASS pragmatically in managing acute stroke patients potentially eligible for thrombolysis; their experience was assessed using self-completion forms and interviews. Computer logged data assessed time in use, and utilisation of graphical risk presentations and additional features. Patients’/relatives’ experiences of discussions supported by COMPASS were explored using interviews. Results COMPASS expresses predicted outcomes (bleeding complications, death, and extent of disability) with and without thrombolysis, presented numerically (percentages and natural frequencies) and graphically (pictographs, bar graphs and flowcharts). COMPASS was used for 25 patients and no adverse effects of use were reported. Median time in use was 2.8 minutes. Graphical risk presentations were shared with 14 patients/relatives. Clinicians (n = 10) valued the patient-specific predictions of benefit from thrombolysis, and the support of better risk communication with patients/relatives. Patients (n = 2) and relatives (n = 6) reported that graphical risk presentations facilitated understanding of benefits/risks of thrombolysis. Additional features (e.g. dosage calculator) were suggested and subsequently embedded within COMPASS to enhance usability. Conclusions Our structured development process led to the development of a gamma prototype computerised decision aid. Initial evaluation has demonstrated reasonable acceptability of COMPASS amongst patients, relatives and clinicians. The impact of COMPASS on clinical outcomes requires wider prospective evaluation in clinical settings. Electronic supplementary material The online version of this article (doi:10.1186/s12911-014-0127-1) contains supplementary material, which is available to authorized users.

The blood pressure rapid intensive lowering and normal treatment for mood and cognition in persistent depression (BRILiANT mood study) was devised as a pilot study to investigate the feasibility and safety of intensive blood pressure lowering as treatment for persistent mood and cognitive symptoms in older adults with major depressive disorder and to assess the availability of this population for recruitment. In addition, the relationship between reduced blood pressure and the change in cerebral blood flow and mood was to be investigated. A single centre pilot randomised controlled trial (RCT), with two parallel groups of intensive or normal treatment for hypertension, recruiting from primary and secondary care and newspaper advert, with an aim of recruiting 66 participants, was observed in this study. At the end of the recruitment period, in order to explore the reasons for failure to recruit to target, surveys were developed and issued to those involved in recruitment. Recruitment rates were lower than expected which led to the study being expanded to further areas and opened to self-referral via advertisement. However, because of better management of hypertension due to changes in the UK Quality and Outcomes Framework guidelines for blood pressure treatment, few eligible patients were identified and the study closed at the end of the recruitment period, with 13 participants consenting, but 12 failing screening resulting in one recruited participant. Overall, the BRILiANT mood study was found not to be feasible, and results suggest that the expected patient population no longer exists. To overcome such recruitment difficulties, a prompt commencement of a study after funding so no relevant care changes occur might help prevent similar problems in future studies. In addition, self-referral, in this case via advertisement in papers, may be a useful tool to increase response rate. When recruiting in primary care, direct access to primary care databases, in a secure and anonymised way, may enable more effective screening. Ultimately, the BRILiANT mood study was shown not to be feasible; this was a useful conclusion from this pilot study. ISRCTN 64524251 ; UKCRN Portfolio No: 13284

Background As in many countries around the world, there are high expectations on academic health science centres and networks in England to provide high-quality care, innovative research, and world-class education, while also supporting wealth creation and economic growth. Meeting these expectations increasingly depends on partnership working between university medical schools and teaching hospitals, as well as other healthcare providers. However, academic-clinical relationships in England are still characterised by the “unlinked partners” model, whereby universities and their partner teaching hospitals are neither fiscally nor structurally linked, creating bifurcating accountabilities to various government and public agencies. Discussion This article focuses on accountability relationships in universities and teaching hospitals, as well as other healthcare providers that form core constituent parts of academic health science centres and networks. The authors analyse accountability for the tripartite mission of patient care, research, and education, using a four-fold typology of accountability relationships, which distinguishes between hierarchical (bureaucratic) accountability, legal accountability, professional accountability, and political accountability. Examples from North West London suggest that a number of mechanisms can be used to improve accountability for the tripartite mission through alignment, but that the simple creation of academic health science centres and networks is probably not sufficient. Summary At the heart of the challenge for academic health science centres and networks is the separation of accountabilities for patient care, research, and education in different government departments. Given that a fundamental top-down system redesign is now extremely unlikely, local academic and clinical leaders face the challenge of aligning their institutions as a matter of priority in order to improve accountability for the tripartite mission from the bottom up. It remains to be seen which alignment mechanisms are most effective, and whether they are strong enough to counter the separation of accountabilities for the tripartite mission at the national level, the on-going structural fragmentation of the health system in England, and the unprecedented financial challenges that it faces. Future research should focus on determining the comparative effectiveness of different alignment mechanisms, developing standardised metrics and key performance indicators, evaluating and assessing academic health science centres and networks, and empirically addressing leadership issues.

To assess sleep-disordered breathing (SDB) in patients with acute stroke and its relationship to prestroke cerebrovascular disease, particularly leukoariosis.The authors studied SDB and CT evidence of prestroke cerebrovascular disease, nonacute brain infarction, and white matter disease (WMD) in 78 previously independent patients with acute stroke. Subjects underwent respiratory sleep studies to determine the Apnea-Hypopnea Index (AHI) and Desaturation Index (DI) 7 to 14 days following stroke. CT scans were evaluated for severity of acute prestroke cerebrovascular disease and WMD severity.Prestroke cerebrovascular disease was present in 49 (63%) patients and was associated with worse SDB (mean AHI 35 vs 23, p0.01; mean DI 28 vs 18, p0.05), particularly in men (mean AHI 43 vs 27, p0.01). WMD severity correlated with AHI (r = 0.26, p0.05) and age (r = 0.56, p0.01). WMD severity in frontal and basal ganglia areas showed the strongest association. On multivariate analysis, WMD severity correlated independently with AHI (R(2) = 0.07, p0.05).The presence of prestroke cerebrovascular disease and severity of WMD are associated with worse SDB. These findings suggest that either white matter is particularly vulnerable to the hypoxia and blood pressure variability associated with SDB or that WMD is a major factor exacerbating SDB following stroke.

Heart rate and blood pressure are linked by the baroreflex mechanism. Baroreflex gain can be estimated from the ratio of RR interval to systolic pressure spectra. This value, /spl alpha/, has units of ms mmHg/sup -1/. The aim of this study was to quantify the effect of using four different techniques for estimating the spectra on estimates of /spl alpha/. Nine healthy subjects were studied. Each relaxed supine for 20 min, ECG (lead II) and finger blood pressure (Finapres) signals were then recorded to computer with a sample rate of 250 Hz. Each recording was 5 min long. RR interval and systolic pressure sequences were resampled at 4 Hz and transformed into the frequency domain using an averaged Fast Fourier Transform (FFT), averaged zero padded FFT (FFTZ), widowed autocovariance function (ACVF) and the maximum entropy method (ME). This study shows that the use of different spectral analysis techniques does not significantly affect estimation of baroreflex gain, /spl alpha/, and that the results of different studies can be compared.

Background Biomedical Research Centres (BRCs) are partnerships between healthcare organisations and universities in England. Their mission is to generate novel treatments, technologies, diagnostics and other interventions that increase the country’s international competitiveness, to rapidly translate these innovations into benefits for patients, and to improve efficiency and reduce waste in healthcare. As NIHR Oxford BRC (Oxford BRC) enters its third 5-year funding period, we seek to (1) apply the evidence base on how best to support the various partnerships in this large, multi-stakeholder research system and (2) research how these partnerships play out in a new, ambitious programme of translational research. Methods Organisational case study, informed by the principles of action research. A cross-cutting theme, ‘Partnerships for Health, Wealth and Innovation’ has been established with multiple sub-themes (drug development, device development, business support and commercialisation, research methodology and statistics, health economics, bioethics, patient and public involvement and engagement, knowledge translation, and education and training) to support individual BRC research themes and generate cross-theme learning. The ‘Partnerships’ theme will support the BRC’s goals by facilitating six types of partnership (with patients and citizens, clinical services, industry, across the NIHR infrastructure, across academic disciplines, and with policymakers and payers) through a range of engagement platforms and activities. We will develop a longitudinal progress narrative centred around exemplar case studies, and apply theoretical models from innovation studies (Triple Helix), sociology of science (Mode 2 knowledge production) and business studies (Value Co-creation). Data sources will be the empirical research studies within individual BRC research themes (who will apply separately for NHS ethics approval), plus documentary analysis and interviews and ethnography with research stakeholders. This study has received ethics clearance through the University of Oxford Central University Research Ethics Committee. Discussion We anticipate that this work will add significant value to Oxford BRC. We predict accelerated knowledge translation; closer alignment of the innovation process with patient priorities and the principles of responsible, ethical research; reduction in research waste; new knowledge about the governance and activities of multi-stakeholder research partnerships and the contexts in which they operate; and capacity-building that reflects the future needs of a rapidly-evolving health research system.

Abstract —Longitudinal studies suggest that hypertension in midlife is associated with cognitive impairment in later life. Cross-sectional studies are difficult to interpret because blood pressure can change with onset of dementia and the inclusion of subjects on treatment and with hypertensive end-organ damage can make analysis difficult. We examined cognitive performance in hypertensive and normotensive subjects without dementia or stroke ≥70 years of age. Cognitive performance was determined with the use of a computerized assessment battery in 107 untreated hypertensives (55 women, age 76±4 years, blood pressure, 164±9/89±7; range, 138 to 179/68 to 99 mm Hg) and 116 normotensives (51 female, age 76±4 years, 131±10/74±7; 108 to 149/60 to 89 mm Hg). Older subjects with hypertension were significantly slower in all tests (reaction time, milliseconds; simple, 346±100 versus 318±56, P P P P P P P =0.08). Accuracy was also impaired in tests of number vigilance, 99.2±2.5% versus 99.9±0.9, P P P

We investigated the role of nitric oxide (NO) in the vascular resistance changes of normotensive and preeclamptic pregnancy. Forearm blood flow (FBF) responses to brachial artery infusion of N G-monomethyl-l-arginine (l-NMMA), an NO synthase inhibitor, and angiotensin II (ANG II), an NO-independent vasoconstrictor, were determined by plethysmography in 20 nonpregnant women, 20 normotensive primigravidae, and 15 primigravidae with untreated preeclampsia. In pregnant subjects, FBF was reduced to nonpregnancy levels by infusion of norepinephrine (NE), which was then coinfused with ANG II (2, 4, and 8 ng/min) and l-NMMA (200, 400, and 800 μg/min) each for 5 min. In separate studies, responses to NE (20, 50, and 100 ng/min) were determined in 8 nonpregnant women, with FBF elevated to pregnancy levels by concomitant infusion of glyceryl trinitrate, and 10 pregnant women. Vasoconstrictor responses tol-NMMA were increased in pregnant compared with nonpregnant subjects [mean ± SE summary measure (in arbitrary units): 60 ± 7 vs. 89 ± 8, respectively; P < 0.01], whereas responses to ANG II were blunted (125 ± 11 vs. 79 ± 7, respectively; P < 0.001). Compared with normotensive pregnant subjects, preeclamptic subjects had an enhanced response to ANG II (79 ± 7 vs. 103 ± 8, respectively; P < 0.05) but no difference in response to l-NMMA (89 ± 8 vs. 73 ± 10, respectively; P = 0.30). Responses to NE were similar in pregnant and nonpregnant subjects (110 ± 20 vs. 95 ± 33, respectively; P = 0.66). During the third trimester of pregnancy, forearm constrictor responses tol-NMMA are increased. The responses to NE are unchanged, whereas responses to ANG II are blunted. Increased NO activity contributes to the fall in peripheral resistance. In preeclampsia, forearm constrictor responses to ANG II but notl-NMMA are increased compared with those in normal pregnancy. Changes in vascular NO activity are unlikely to account for the increased vascular tone in this condition.

We sought to determine whether the enhanced forearm vascular activity of nitric oxide during pregnancy and preeclampsia is associated with altered smooth muscle sensitivity to nitric oxide or with stimulated nitric oxide release.Forearm blood flow responses to brachial artery infusion of glyceryl trinitrate (a nitric oxide donor), serotonin (an endothelium-dependent nitric oxide-mediated agonist), and ritodrine (a beta-adrenergic receptor agonist) were studied in 10 nonpregnant women, 12 pregnant women, and 7 women with preeclampsia by means of strain-gauge plethysmography. Responses to each drug (maximum dilator response and the sum of the percentage of dilator responses to each drug) were compared by analysis of variance.Compared with nonpregnant women, pregnant subjects showed reduced responses to serotonin (summary response, 117 +/- 19 vs 221 +/- 30; P.05). Responses to serotonin were reduced in the group with preeclampsia compared with those in the nonpregnant group (summary response, 71 +/- 28; P.05) but did not differ from the responses in pregnant women. There were no differences between responses to glyceryl trinitrate and responses to ritodrine in any of the groups.Vascular smooth muscle sensitivity to nitric oxide is not altered in normal pregnancy or preeclampsia, but dilator responses to serotonin appear blunted. Alterations in serotonin receptor coupling to nitric oxide synthase, or a limitation of availability of the substrate for nitric oxide synthase (L-arginine) during pregnancy, could account for the reduction in stimulated nitric oxide release.

Summary A 28 year old man presented with haematuria and renal failure. Renal arteriography revealed bleeding into the pelvis of a solitary right kidney from a hilar artery. Multiple aneurysms were noted in the splenic artery. The spleen subsequently ruptured spontaneously and was removed at laparotomy together with the right kidney. Histological examination of the spleen and kidney revealed an acute necrotizing vasculitis involving medium-sized and smaller arteries confirming a diagnosis of polyarteritis nodosa. An area of infarction involved a subcapsular area of the spleen. Spontaneous splenic rupture is a rare but important complication of systemic vasculitides.

SUMMARY The estimation of corneal endothelium mean cell area (and, hence, mean cell density) is an important problem in clinical ophthalmology. Mitotic division of these cells is not known to occur, and cell deaths are followed by the enlargement of adjacent cells. As a consequence, cell-area distributions change drastically as functions of age and disease. Changes in cell-area distributions, in particular multimodality and skewness due to aging, are observed, and give rise to some difficult sampling problems. In this paper, sample quantiles are investigated as an alternative to the use of the sample mean. Asymptotic approximations are provided for the sample sizes required to estimate population quantiles with a desired precision. Asymptotic sample sizes are then compared with those obtained from tolerance limits. Empirical sample quantiles that can be used as benchmarks to compare corneas of normal individuals against corneas with unknown cell-area distributions are also presented. Aspects that merit further investigation are noted.

(This paper has been accepted for publication in the Proceedings, but the photo-ready from was not delivered in time. Copies of the paper should be available upon request at the presentation.)

The effects of nematodiasis on productivity in weaner sheep was measured at Kybybolite Research Centre, South Australia, during 1976-81. Three levels of control were compared at two stocking rates (7.5 ha-1 and 16 ha-1). One group was not treated with anthelmintics, another group was treated every 3 weeks and the third group (Planned) was given five doses of anthelmintics each year: once in October, twice during the hot dry summer and twice during the winter months. The sheep were replaced by weaner sheep at shearing in October each year. The drenching regime of sheep on a particular paddock was the same for all five years. Nematodes, particularly Trichostrongylus spp., had a very large effect on the production of the sheep. The mean annual death rate of the untreated sheep was 22% and 56070, for the low and high stocking rates respectively. The regularly drenched sheep were 9-31% heavier and cut 11-46% more wool than the survivors of the untreated sheep at the low stocking rate. At the high stocking rate the regularly drenched sheep were 17-58% heavier and cut 14-56% more wool than the survivors of the undrenched sheep. The sheep given the Planned drenching program had similar final liveweights each year to the regularly drenched sheep, and in only two years out of five did the regularly drenched sheep produce significantly more wool than the sheep given the Planned program. The effect of drenching on the contamination of wool with faeces, and the resultant effect on the incidence of fly strike, is discussed. There was a significant variation between years in amount of available pasture, and there was generally slightly more pasture available on the Nil drench treatment paddocks.

A replication of the 1970 Safeway unit pricing study found substantial differences having both substantive and methodological implications.

Causes of mortality in weaner sheep subjected to differing regimes of anthelmintic treatment were investigated at Kybybolite, S.A., between 1976 and 1981. The greatest mortality occurred in untreated sheep during the winter months, and was directly attributable to nematode infections, principally Trichostrongylus vitrinus. Deaths occurred during the summer months of the later years of the experiment. Nematode infections were considered to be a predisposing cause, with anaemia possibly due to infection with Eperythrozoon ovis as the precipitating factor in mortalities.

Electrophoretic variants of enzymes from 100 individual macroscopic sarcocysts from sheep carcasses were examined to see if they could serve as genetic markers for the identification of ovine sarcosporidia. Of the 31 enzymes screened, 12 that represented single genetic loci were tested. There were two patterns of isoenzyme mobility, which differed at. 7 out of 12 of the loci being studied, and corresponded to enzymes from either 'fat' or 'thin' cysts, indicating that these two sarcocyst types may be considered quite different species. In a parallel study, extracts of microscopic sarcocysts digested from sheep heart muscle were compared with those from macroscopic sarcocysts and found to have a distinct electrophoretic isoenzyme profile for each of four loci.

A new algorithm is presented for the determination of the locations of major edges in a noisy image based, in part, on the approach of maximum-likelihood estimation.