Diagnostic sensitivity and specificity of immunohistochemistry for the detection of rabies virus in domestic and wild animals in South Africa

We estimated the diagnostic sensitivity (DSe) and specificity (DSp) of an immunohistochemistry (IHC) protocol compared to the direct fluorescent antibody test (DFAT), which is the gold standard test for rabies diagnosis. We obtained brain samples from 199 domestic and wild animal cases (100 DFAT-negative, 99 DFAT-positive), by convenience sampling from 2 government-accredited rabies virus (RABV) testing laboratories in South Africa, between February 2015 and August 2017. Tissues that had been stored at 4-8°C for several days to weeks at the 2 accredited laboratories were formalin-fixed and paraffin-embedded. Nighty-eight cases tested IHC-positive using a polyclonal anti-RABV nucleoprotein antibody and a polymer detection system. The overall DSe and DSp for the RABV IHC test were 98% (95% CI: 93-100%) and 99% (95% CI: 95-100%), respectively. Domestic dogs accounted for 41 of 98 RABV IHC-positive cases, with the remainder in 4 domestic cats, 25 livestock, and 28 wildlife. Herpestidae species, including 7 meerkats and 9 other mongoose species, were the most frequently infected wild carnivores, followed by 11 jackals. Three cases in domestic dogs had discordant test results; 2 cases were IHC-/DFAT+ and 1 case was IHC+/DFAT-. Considering the implications of a false-negative rabies diagnosis, participating in regular inter-laboratory comparisons is vital, and a secondary or confirmatory method, such as IHC, should be performed on all submitted specimens, particularly negative cases with human contact history.

Theileriosis in naturally infected roan antelope (Hippotragus equinus)

Cases of Theileria-associated mortality are rarely reported in African wild artiodactyls. Descriptions of lesions are limited, particularly in endangered hippotraginids. Here, we analyzed retrospectively the gross and histologic findings in 55 roan antelope (Hippotragus equinus) with fatal natural theileriosis. The most frequently recorded gross findings in 40 cases were widespread petechiae and ecchymoses (72.5%), probable anemia (67.5%), icterus (60%), splenomegaly (60%), hepatomegaly (52.5%), and pulmonary edema (50%). Histologic lesions in 34 cases were characterized by multi-organ infiltrates of parasitized and nonparasitized mononuclear leukocytes (MLs), and fewer multinucleate giant cells (MNGCs). Liver, lung, kidney, adrenal gland, and heart were most consistently infiltrated, followed by spleen and lymph nodes. Leukocytes were phenotyped in lung, liver, kidney, and heart specimens from 16 cases, using immunohistochemistry to detect CD20, CD3, myeloid/histiocyte antigen (MAC387), IBA-1, and CD204 surface receptors. A roan polyclonal anti-Theileria sp. (sable) antibody was applied to the same tissues to identify intraleukocytic parasite antigens. Similar proportions of intravascular and extravascular IBA-1-, CD204-, and MAC387-reactive putative monocyte-macrophages and fewer CD3-positive putative T-lymphocytes were identified in all organs, especially the lungs in infected roan. CD20-positive putative B-lymphocytes were significantly scarcer than in uninfected controls. Intraleukocytic Theileria parasites labeled consistently in affected tissues. Some parasitized and nonparasitized MLs and the MNGCs failed to label with selected leukocyte markers. Fatal theileriosis in roans may largely be the result of multi-organ monocyte-macrophage activation with associated tissue injury and overwhelming systemic inflammation. The identity of the parasitized leukocytes and characteristics of the lymphohistiocytic response require further clarification in roans.

Ontogeny of the testicular excurrent duct system of male Japanese quail (Coturnix japonica): A histological, ultrastructural, and histometric study

The testicular excurrent duct system undergoes several physiological and morphological changes during the reproductive stage or breeding season in mammals, birds, and reptiles. Studies on normal age-related histomorphological changes in the excurrent duct system of Japanese quails (Coturnix japonica) remain unreported, despite the extensive use of this bird as an avian model in research studies. The current study investigated the histological, ultrastructural, and histometric changes in the testicular excurrent duct system of the Japanese quail during three reproductive stages, namely prepubertal, pubertal, and adult. Simple squamous to low cuboidal cells formed the epithelia of the rete testis in prepubertal and pubertal birds, while in adult birds the lining was low cuboidal to cuboidal. In pubertal and adult birds, the nonciliated Type I epithelial cells of the proximal efferent duct displayed a subapical endocytotic apparatus comprising coated pits, coated apical tubules, and endosomes. There was a significant increase (p ≤ .001) in epithelial heights of all ducts of the excurrent duct system in the mature, sexually active, adult birds when compared to the other age groups. The luminal and tubular diameters, and the cross-sectional areas of efferent ducts and the epididymal duct unit increased significantly (p ≤ .001) with age. It is concluded that the morphology and morphometry of the excurrent ducts of the testis of the Japanese quail change as birds mature.

Rabies of canid biotype in wild dog (Lycaon pictus) and spotted hyaena (Crocuta crocuta) in Madikwe Game Reserve, South Africa in 2014-2015: Diagnosis, possible origins and implications for control

Both domestic and wild carnivore species are commonly diagnosed with rabies virus (RABV) infection in South Africa. Although the majority of confirmed rabies cases in wild carnivore species are reported from the yellow mongoose (Cynictis penicillata), the rest are from other wild carnivores including the highly endangered wild dog (Lycaon pictus). Lyssavirus infection was confirmed in two wild dogs and a spotted hyaena (Crocuta crocuta) in the Madikwe Game Reserve, North West province in South Africa, in 2014 and 2015, using a direct fluorescent antibody test and immunohistochemistry. There had been no new wild dog introductions to the Madikwe Game Reserve for many years and the wild dogs were last vaccinated against rabies approximately 11 years prior to the incident. The first euthanised wild dog was the last surviving of a break-away pack of 6, and the second was the last of a larger pack of 18, the rest of which died with no carcasses being found or carcasses too decomposed for sampling. Subsequent antigenic typing of the lyssaviruses indicated that they were canid RABVs. The RABVs originating from 22 wild carnivore species, 7 dogs, and a caprine, mostly from the North West province, were genetically characterised by targeting a partial region of the nucleoprotein gene. The nucleotide sequence analyses of these viruses and two previously characterised RABVs confirmed that the outbreak viruses were also canid rabies, phylogenetically clustering with virus isolates originating from black-backed jackals recovered between 2012 and 2015 from the North West province, and domestic dogs from neighbouring communal areas. The source(s) of the mortalities and possible reservoir host(s) for the virus could only be speculated upon from data on specific predator numbers, movements and behaviour, kills, park management and the changing environmental ecology, which were monitored closely in Madikwe over several years. The most likely rabies sources were from boundary fence contacts between wild carnivores within the park, with domestic dogs or cats and/or naturally occurring wild carnivores outside the park. The associated risk of zoonotic infection and threat to important and endangered predators may be mitigated through regional rabies control primarily in domestic dogs and cats, as well as by preventative vaccination of at-risk park employees and their pets. The importance of ongoing prophylactic rabies protection by regular vaccination of highly endangered wildlife carnivores and the submission of carcasses for rabies diagnosis of any wild or domestic animals behaving uncharacteristically or found dead is emphasised.

The cost of a patient activation intervention for achieving successful outcomes: results from the PAADRN randomized controlled trial

In a large, pragmatic clinical trial, we calculated the costs of achieving four successful patient-centered outcomes using a tailored patient activation DXA result letter accompanied by a bone health brochure. The cost to achieve one successful outcome (e.g., a 0.5 standard deviation improvement in care satisfaction) ranged from $127.41 to $222.75.

INTRODUCTION

Pragmatic randomized controlled trials (RCTs) should focus on patient-centered outcomes and report the costs for achieving those outcomes. We calculated per person incremental intervention costs, the number-needed-to-treat (NNT), and incremental per patient costs (cost per NNT) for four patient-centered outcomes in a direct-to-patient bone healthcare intervention.

METHODS

The Patient Activation after DXA Result Notification (PAADRN) pragmatic RCT enrolled 7749 patients presenting for DXA at three health centers between February 2012 and August 2014. Interviews occurred at baseline and 52 weeks post-DXA. Intervention subjects received an individually tailored DXA result letter accompanied by an educational bone health brochure 4 weeks post-DXA, while the usual care subjects did not. Outcomes focused on patients (a) correctly identifying their results, (b) contacting their providers, (c) discussing their results with their providers, and (d) satisfaction with their bone healthcare. NNTs were determined using intention-to-treat linear probability models, per person incremental intervention costs were calculated, and costs per NNT were computed.

RESULTS

Mean age was 66.6 years old, 83.8% were women, and 75.3% were non-Hispanic whites. The incremental per patient cost (costs per NNT) to increase the ability of a patient to (a) correctly identify their DXA result was $171.07; (b) contact their provider about their DXA result was $222.75; (c) discuss their DXA result with their provider was $193.55; and (d) achieve a 0.5 SD improvement in satisfaction with their bone healthcare was $127.41.

CONCLUSION

An individually tailored DXA result letter accompanied by an educational brochure can improve four patient-centered outcomes at a modest cost.

TRIAL REGISTRATION

clinicaltrials.gov identifier NCT01507662.

Paraquat intoxication and associated pathological findings in three dogs in South Africa

Paraquat is a bipyridylium non-selective contact herbicide commonly used worldwide. When ingestion occurs by humans and animals either accidentally, intentionally or maliciously, paraquat selectively accumulates in the lungs resulting in the production of oxygen-free radicals, causing membrane damage and cell death. Intoxicated subjects typically show progressive and fatal pulmonary haemorrhage, collapse and oedema. In individuals surviving the acute phase, pulmonary fibrosis develops. Gastrointestinal-, renal- and central nervous system clinical signs may also occur. Owing to the lack of effective treatment and absence of an antidote, the prognosis is poor. The clinical presentation, clinicopathological findings and treatment are briefly described of three dogs from one South African household, intoxicated with paraquat. Macroscopic and microscopic lesions in one dog that was necropsied, as well as pulmonary ultrastructure are detailed and illustrated for academic reference. All dogs presented with tachypnoea and dyspnoea 2-3 days after accidental paraquat ingestion. Treatment was aimed at reducing gastrointestinal absorption, enhancing elimination by diuresis and avoiding further oxidative damage by administration of antioxidants. All dogs, however, became progressively hypoxic despite treatment and were euthanised. Paraquat toxicity should be a differential diagnosis in dogs with unexplained progressive respiratory and gastrointestinal signs and renal failure. The local veterinary profession should be aware of accidental or intentional paraquat toxicity of animals. Existing literature, variations possible in canine clinical signs, measured parameters, lesions, as well as possible treatments, promising experimental antidotes and management options are discussed.

Pathology of fatal lineage 1 and 2 West Nile virus infections in horses in South Africa

Since 2007, West Nile virus (WNV) has been reported in South African horses, causing severe neurological signs. All cases were of lineage 2, except for one case that clustered with lineage 1 viruses. In the present study, gross and microscopic lesions of six South African lineage 2-infected horses and the one lineage 1 case are described. Diagnoses were confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR) of central nervous system (CNS) tissue and one by RT-PCR of a brain virus isolate. The CNS of all cases was negative by RT-PCR or immunohistochemistry (IHC) for African horse sickness (AHS), equine encephalosis virus, equine herpes viruses 1 and 4, other zoonotic flaviviruses, alphaviruses, and shunivirus, and either by immunofluorescence or IHC for rabies. Gross visceral lesions were nonspecific but often mimicked those of AHS. The CNS histopathology of WNV lineage 2 cases resembled the nonsuppurative polioencephalomyelitis reported in the Northern Hemisphere lineage 1 and recent Hungarian lineage 2 cases. Occasional meningitis, focal spinal ventral horn poliomalacia, dorsal and lateral horn poliomyelitis, leucomyelitis, asymmetrical ventral motor spinal neuritis and frequent olfactory region involvement were also seen. Lineage 2 cases displayed marked variations in CNS lesion severity, type and distribution, and suggested various viral entry routes into the CNS, based on findings in experimental mice and hamsters. Lineage 1 lesions were comparable to the milder lineage 2 cases. West Nile virus IHC on CNS sections with marked lesions from all cases elicited only two antigen-positive cells in the olfactory cortex of one case. The presence in the CNS of T-lymphocytes, B-lymphocytes, plasma cells and macrophage-monocytes was confirmed by cluster of differentiation (CD) 3, CD20, multiple myeloma oncogene 1 (MUM1) and macrophage (MAC) 387 IHC.

Analytical confirmation of Xanthium strumarium poisoning in cattle

Xanthium strumarium, commonly referred to as “cocklebur,” rarely causes poisoning in cattle. When mature, this robust, annual weed bears numerous oval, brownish, spiny burs. Only the seeds in the burs and young seedlings (cotyledonary leaves) contain the toxic principle, carboxyatractyloside. In the Frankfort district of the Free State Province of South Africa, a herd of 150 Bonsmara cows were allowed to graze on the banks of a small river, where mature cocklebur was growing. Four cows died while grazing in this relatively small area. Clinical signs ranged from recumbency, apparent blindness, and hypersensitivity to convulsive seizures. During necropsy, burs completely matted with ingesta were located in the rumen content. The most distinctive microscopic lesions were severe, bridging centrilobular to midzonal hepatocyte necrosis and hemorrhage. Ultrastructurally, periacinar hepatocytes were necrotic, and novel electron-dense cytoplasmic needle-like crystals were observed, often in close association with peroxisomes. Carboxyatractyloside concentrations were determined using liquid chromatography–high-resolution mass spectrometry (LC-HRMS). Carboxyatractyloside was present in rumen contents at 2.5 mg/kg; in burs removed from the rumen at 0.17 mg/kg; in liver at 66 ng/g, and was below the limit of quantitation in the kidney sample, estimated at approximately 0.8 ng/g. Based on the presence of the plants on the riverbank, the history of exposure, the clinical findings, the presence of burs in the rumen, and the microscopic and ultrastructural lesions, X. strumarium poisoning in the herd of cattle was confirmed and was supported by LC-HRMS.

Comparative pathology of neurovirulent lineage 1 (NY99/385) and lineage 2 (SPU93/01) West Nile virus infections in BALBc mice

The pathology in mice infected with neurovirulent South African lineage 2 West Nile virus (WNV) strains has not previously been described. Three- to 4-month-old male BALBc mice were infected with South African neurovirulent lineage 2 (SPU93/01) or lineage 1 (NY385/99) WNV strains and the gross and microscopic central nervous system (CNS) and extra-CNS pathology of both investigated and compared. Mice infected with both lineages showed similar illness, paralysis, and death from days 7 to 11 postinfection (PI). Two survivors of each lineage were euthanized on day 21 PI. WNV infection was confirmed by nested real-time reverse transcription polymerase chain reaction of tissues, mostly brain, in the majority of mice euthanized sick or that died and in 1 healthy lineage 2 survivor. Gross lesions caused by both lineages were identical and included marked gastric and proximal small intestinal fluid distension as described in a previous mouse study, but intestinal microscopic lesions differed. CNS lesions were subtle. Immunohistochemical (IHC)-positive labeling for WNV E protein was found in neurons multifocally in the brain of 3 lineage 1-infected and 3 lineage 2-infected mice from days 9 to 11 PI, 4 of these including brainstem neurons, and of cecal myenteric ganglion neurons in 1 lineage 2-infected day 8 PI mouse. Findings supported hypotheses in hamsters that gastrointestinal lesions are likely of brainstem origin. Ultrastructurally, virus-associated cytoplasmic vesicular or crystalline structures, or amorphous structures, were found to label IHC positive in control-positive avian cardiomyocytes and mouse thalamic neurons, respectively, and WNV-like 50-nm particles, which were scarce, did not label.

Association between high aflatoxin B1 levels and high viral load in HIV-positive people

Since both aflatoxin and the human immunodeficiency virus (HIV) cause immune suppression, chronic exposure to aflatoxin in HIV-positive people could lead to higher levels of virus replication. This study was conducted to examine the association between aflatoxin B₁ albumin adduct (AF-ALB) levels and HIV viral load. Antiretroviral naive HIV-positive people (314) with median CD4 count of 574 cells/μl blood (mean ± standard deviation = 630±277) were recruited in Kumasi, Ghana. Sociodemographic and health data, and blood samples were collected from participants. The plasma samples were tested for AF-ALB and HIV viral load. Univariate logistic regression analysis was conducted using viral load (high/low) as the outcome and AF-ALB quartiles as exposure. Multivariable logistic regression analysis was performed between quartile AF-ALB, viral load and CD4 adjusting for sex, age, and year of HIV diagnosis. Both univariate and multivariable logistic regression showed that viral load increased as AF-ALB levels increased. By univariate analysis, high viral load was 2.3 times more likely among persons in the third AF-ALB quartile (95% confidence interval (Cl): 1.13, 4.51), and 2.9 times more likely among persons in the fourth AF-ALB quartile (Cl: 1.41, 5.88), compared to persons in the first quartile. In the multivariable model, persons in the fourth AF-ALB quartile were about 2.6 times more likely to have high viral loads than persons in the first quartile (Cl: 1.19-5.69). When AF-ALB and viral load were log transformed and linear regression analysis conducted, the univariate linear regression analysis showed that for each pg/mg increase in AF-ALB, viral load increased by approximately 1.6 copies/ml (P=0.0006). The association was marginally significant in the adjusted linear regression model (i.e. for each pg/mg increase in AF-ALB, the mean viral load increased by approximately 1.3 copies/ml, P=0.073). These data show strong and consistent increases in HIV viral load with increasing AF-ALB levels. Since the median and mean CD4 were greater than 500 cells for participants in each AF-ALB quartile, the results indicate that the immune modulating and virus transcription effects of aflatoxin may occur quite early in HIV infection, even while the CD4 count is still above 500, resulting in higher viral loads.

Fatal disseminated toxoplasmosis in an immunocompetent cat

A 10-year-old domestic short hair cat was referred for investigation of anorexia and polydipsia of 3 days’ duration. Clinically the cat was obese, pyrexic (39.8 °C), had acute abdominal pain and severe bilirubinuria. Haematology and serum biochemistry revealed severe panleukopenia, thrombocytopenia, markedly elevated alanine aminotransferase (ALT) and five-fold increased pre-prandial bile acids. Ultrasonographic evaluation of the abdomen did not identify any abnormalities. Serum tests for feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) were negative. Broad-spectrum antibiotic treatment for infectious hepatitis was to no avail; the cat deteriorated and died 72 h after admission. Necropsy revealed mild icterus and anaemia, severe multifocal hepatic necrosis, serofibrinous hydrothorax, pulmonary oedema and interstitial pneumonia. Histopathology confirmed the macroscopic findings and revealed multifocal microgranulomata in the brain and myocardium, as well as areas of necrosis in lymph nodes and multifocally in splenic red pulp. Long bone shaft marrow was hyperplastic with a predominance of leukocyte precursors and megakaryocytes and splenic red pulp showed mild extramedullary haemopoiesis. Immunohistochemical staining for Toxoplasma gondii was strongly positive, with scattered cysts and tachyzoites in the liver, lymph nodes, spleen, lungs, brain, salivary glands and intracellularly in round cells in occasional blood vessels. Immunohistochemical staining for corona virus on the same tissues was negative, ruling out feline infectious peritonitis (FIP). Polymerase chain reaction (PCR) on formalin-fixed paraffin-wax embedded tissues was positive for Toxoplasma sp., but attempts at sequencing were unsuccessful. This was the first case report of fulminant disseminated toxoplasmosis in South Africa, in which detailed histopathology in an apparently immunocompetent cat was described.

Development of early tissue cysts and associated pathology of Besnoitia besnoiti in a naturally infected bull (Bos taurus) from South Africa

Besnoitia besnoiti is an apicomplexan that causes serious economic loss in cattle in many countries and the disease is now spreading in Europe. At least 2 phases of bovine besnoitiosis are recognized clinically. An acute febrile phase characterized by anasarca and necrosis of skin is associated with multiplication of tachyzoites in vascular endothelium; this phase is short-lived and rarely diagnosed. Chronic besnoitiosis characterized by dermal lesions is associated with the presence of macroscopic tissue cysts and is easily diagnosed. Here we report the development of early B. besnoiti tissue cysts in a naturally infected Hugenoot bull from South Africa. Tissue cysts were 10-70 μm in diameter, contained 1-12 bradyzoites, and were most numerous in the dermis, testicles, and pampiniform venous plexus. Amylopectin granules in bradyzoites stained red with periodic acid Schiff (PAS) reaction. Bradyzoites varied in size and in the intensity of PAS reaction (some were PAS-negative), some were plump, and others were slender. With immunohistochemical staining with Besnoitia oryctofelisi and bradyzoite-specific antibodies (BAG-1 made against Toxoplasma gondii bradyzoites), the staining was confined to parasites, and all intracystic organisms were BAG-1 positive. With Gomori's silver stain only bradyzoites were stained very faintly whereas the rest of the tissue cyst was unstained. Ultrastructurally many tissue cysts contained dead bradyzoites and some appeared empty. Unlike bradyzoites from mature cysts, bradyzoites in the present case contained few or no micronemes. These findings are of diagnostic significance. Ultrastructually host cyst cells had features of myofibroblasts, and immunohistochemistry using antibodies against MAC387, lysozyme, vimentin, Von Willebrand factor, and smooth muscle actin confirmed this. Polymerase chain reaction on DNA extracted from lymph node of the bull confirmed B. besnoiti diagnosis. Associated clinical findings, lesions, and histopathology are briefly presented. The bull died of nephrotic syndrome; anasarca in acute besnoitiosis due to protein-losing glomerulopathy is a finding not previously reported in cattle.

Socio-demographic determinants of aflatoxin B1-lysine adduct levels among pregnant women in Kumasi, Ghana

OBJECTIVES

Aflatoxins are fungal metabolites that contaminate staple food crops in many developing countries. Although studies have linked these toxins to adverse birth outcomes and poor infant development, no study has investigated the socio-demographic and economic determinants of aflatoxin levels among pregnant women living in sub-Saharan Africa.

DESIGN

A cross-sectional study was conducted among 785 pregnant women in Kumasi. Aflatoxin B1 lysine adduct levels (AF-ALB) were determined by High Performance Liquid Chromatography. Analysis of variance was used to determine mean log AF-ALB levels and significance of differences in these levels according to socio-demographic variables. Logistic regression was used to identify independent associations of socio-demographics with having AF-ALB levels (≥ 11.34 pg/mg; upper quartile).

RESULTS

AF-ALB levels ranged from 0.44 pg/mg to 268.73 pg/mg albumin with a median level of 5.0 pg/mg. Bivariate analyses indicates that mean ln AF-ALB as well as the percent of women having high AF-ALB levels (≥ 11.34 pg/mg; upper quartile) were inversely associated with indices of higher socioeconomic status: higher education and income, being employed and having a flush toilet. Higher income, being employed, having one child (verses no children) and having a flush toilet (verses no toilet facilities) were each independently associated with a 30-40% reduced odds of high AF-ALB levels.

CONCLUSIONS

Additional research is needed to investigate how socio-demographic and economic factors interact to influence aflatoxin ingestion by individuals in regions with high aflatoxin crop contamination. This knowledge can be used to formulate and implement policies that will reduce exposure of women and their unborn children to these toxins.

Smoking cessation post-discharge following nicotine replacement therapy use during an inpatient admission

BACKGROUND

Cigarette smoking remains a health issue despite declining prevalence in Australia. The burden of tobacco-related morbidity affects hospitals, particularly those in lower socioeconomic areas where prevalence is highest.

AIM

We have shown that nicotine replacement therapy (NRT) use during hospitalization increases motivation to quit post-discharge. We postulated that subjects using the nicotine patch post-discharge, in comparison to the inhaler, would have higher rates of abstinence at 12 months after discharge. The aim was to compare the efficacy of the nicotine patch or inhaler formulation for cessation post-discharge, following use during admission.

METHODS

Post-discharge, subjects chose their preferred formulation (patch or inhaler) based on their experience with NRT during admission. Tailored, medium-intensity support was provided with subsidized NRT during outpatient visits. Subjects were followed for 12 months. Exhaled breath CO confirmed non-smoking.

RESULTS

Of 123 subjects enrolled, 37 elected to use the inhaler, 50 the patch and 36 no NRT. At 12 months continuous abstinence rates were 38%, 38% and 25% respectively.

DISCUSSION

This study built upon the 'teachable moment' provided by hospitalization and the inpatient use of NRT, encouraging cessation post-discharge. Both NRT formulations provided similar 12 month cessation rates, and were superior to those achieved by subjects electing not to use NRT. Although the patch was the most popular formulation, the inhaler provided an equally efficacious alternative which addressed other facets of cigarette addiction. Subjects electing not to use NRT were less successful. Continuous abstinence rates were equivalent to community-based studies using NRT. We recommend a similar programme to other hospitals.

Barbiturate ingestion in three adult captive tigers (Panthera tigris) and concomitant fatal botulism of one

Zoo animals, including tigers, have been reported to suffer from barbiturate intoxication, with pentabarbitone being most commonly recorded. Clinical signs range from mild ataxia to general anaesthesia with recovery over hours to days with several factors affecting hepatic barbiturate metabolism and tissue partitioning. Botulism is an often fatal intoxication in man, animals, birds and certain fish. The occurrence in carnivores is uncommon to rare, with only 2 reports found of botulism in felids. This report relates to 3 adult captive cohabiting tigers that simultaneously developed signs of abdominal discomfort, progressive ataxia, recumbency and comatose sleep resembling stage 2 anaesthesia, alternating with periods of distracted wakefulness and ataxic movements. These signs occurred 4 days after being fed the carcass of a horse that had ostensibly died of colic and not been euthanased. The male tiger that was the dominant animal in the feeding hierarchy was worst affected and had to be given intravenous fluids. The female that was lowest in hierarchy was unaffected. After 48-72 hours of treatment at the Onderstepoort Veterinary Academic Hospital the females could eat and made an uneventful recovery. The male tiger showed partial recovery but died during the night a few hours after drinking water on his return to the owner. Necropsy revealed severe oesophageal dilation and impaction with decaying grass; some of this material and water were present in the pharynx and trachea, and had been aspirated causing acute widespread bronchopneumonia. Colon content tested negative for common pesticides but, together with liver, tested positive for barbiturate. Serum taken on the day of admission had tested negative for barbiturate and the residual serum from the 3 animals later tested negative for botulinum toxin. Colon and oesophageal content from the male at necropsy were positive for Clostridium botulinum toxin type C by the mouse bioassay neutralisation test, confirming that this male had had concomitant barbiturate toxicity and botulism, and had succumbed to aspiration bronchopneumonia secondary to pharyngeal, laryngeal and oesophageal paralysis and oesophageal

Shuni virus as cause of neurologic disease in horses

To determine which agents cause neurologic disease in horses, we conducted reverse transcription PCR on isolates from of a horse with encephalitis and 111 other horses with acute disease. Shuni virus was found in 7 horses, 5 of which had neurologic signs. Testing for lesser known viruses should be considered for horses with unexplained illness.

Association of high viral load and abnormal liver function with high aflatoxin B1-albumin adduct levels in HIV-positive Ghanaians: preliminary observations

We examined the association between certain clinical factors and aflatoxin B(1)-albumin adduct (AF-ALB) levels in HIV-positive people. Plasma samples collected from 314 (155 HIV-positive and 159 HIV-negative) people were tested for AF-ALB levels, viral load, CD4+ T-cell count, liver function profile, malaria parasitaemia, and hepatitis B and C virus infections. HIV-positive participants were divided into high and low groups based on their median AF-ALB of 0.93 pmol mg(-1) albumin and multivariable logistic and linear regression methods used to assess relationships between clinical conditions and AF-ALB levels. Multivariable logistic regression showed statistically significant increased odds of having higher HIV viral loads (OR=2.84; 95% CI=1.17-7.78) and higher direct bilirubin levels (OR=5.47; 95% CI=1.03-22.85) among HIV-positive participants in the high AF-ALB group. There were also higher levels of total bilirubin and lower levels of albumin in association with high AF-ALB. Thus, aflatoxin exposure may contribute to high viral loads and abnormal liver function in HIV-positive people and so promote disease progression.

Pathology and immunohistochemistry of papillomavirus-associated cutaneous lesions in Cape mountain zebra, giraffe, sable antelope and African buffalo in South Africa

Skin lesions associated with papillomaviruses have been reported in many animal species and man. Bovine papillomavirus (BVP) affects mainly the epidermis, but also the dermis in several species including bovine, the best-known example being equine sarcoid, which is associated with BVP types 1 and 2. This publication describes and illustrates the macroscopic and histological appearance of BPV-associated papillomatous, fibropapillomatous or sarcoid-like lesions in Cape mountain zebra (Equus zebra zebra) from the Gariep Dam Nature Reserve, 2 giraffes (Giraffa camelopardalis) from the Kruger National Park, and a sable antelope (Hippotragus niger) from the Kimberley area of South Africa. An African buffalo (Syncerus caffer) cow from Kruger National Park also had papillomatous lesions but molecular characterisation of lesional virus was not done. Immunohistochemical staining using polyclonal rabbit antiserum to chemically disrupted BPV-1, which cross-reacts with the L1 capsid of most known papillomaviruses, was positive in cells of the stratum granulosum of lesions in Giraffe 1, the sable and the buffalo and negative in those of the zebra and Giraffe 2. Fibropapillomatous and sarcoid-like lesions from an adult bovine were used as positive control for the immunohistochemistry and are described and the immunohistochemistry illustrated for comparison. Macroscopically, both adult female giraffe had severely thickened multifocal to coalescing nodular and occasionally ulcerated lesions of the head, neck and trunk with local poorly-circumscribed invasion into the subcutis. Necropsy performed on the 2nd giraffe revealed neither internal metastases nor serious underlying disease. Giraffe 1 had scattered, and Giraffe 2 numerous, large, anaplastic, at times indistinctly multinucleated dermal fibroblasts with bizarre nuclei within the sarcoid-like lesions, which were BPV-1 positive in Giraffe 1 and BPV-1 and -2 positive in Giraffe 2 by RT-PCR. The sable antelope presented with a solitary large lesion just proximal to the right hind hoof, which recurred after excision, and was BPV-1 positive by RT-PCR. Other wart-like growths were present elsewhere on the body. The Cape mountain zebra either succumbed from their massive lesions or were euthanased or removed from the herd because of them. The lesions were BPV-1 and/or -2 positive by RT-PCR. The buffalo lesions were wart-like papillomatous projections in the inguinal and udder region. Stratum granulosum cells that stained immunohistochemically positive in the various species appeared koilocyte-like, as described in human papillomaviral lesions.

Infiltrative angiolipoma of the parotid salivary gland in a dog

Solitary benign angiolipoma and infiltrative angiolipoma are rare tumours in dogs. Angiolipomata can be distinguished histologically from lipomata by the large number of tightly packed blood vessels seen between the adipocytes with multiple fibrin thrombi occupying some of the vessels' lumens. The dog presented with a solitary slow-growing mass in the cervical region. Histopathology revealed multifocal to coalescing single or clusters of blood-filled vessels lined by flattened endothelial cells with narrow, elongated, basophilic nuclei. These regions were embedded in adipose tissue with multifocal areas of intervascular remnants of differentiated serous salivary glandular tissue with multifocal small ducts. Fibrin thrombi occupied a few of the vessel lumens. A histological diagnosis of infiltrative angiolipoma was made. On computed tomography, the mass was bilobed with a suspected primary component involving the right parotid gland which was grossly enlarged. The mass had a slightly hypoattenuating mottled to lobulated appearance with a few hyperattenuating mineralised specks throughout. Hounsfield units of the mass ranged between 40 and 45, which was less than the 60-65 of the contralateral salivary glands and cranial musculature. Post contrast images showed no contrast enhancement of 90% of the mass with only a band of peripheral contrast uptake of the affected lateral lobe.

Aflatoxin-albumin adducts and correlation with decreased serum levels of vitamins A and E in an adult Ghanaian population

A study of aflatoxin (AF) exposure and the levels of vitamins A and E was carried out with a group of 507 Ghanaian participants. AFB(1)-albumin adducts (AFB-AA) were measured by radioimmunoassay and vitamins A and E were measured by high-performance liquid chromatography (HPLC). The average level of serum AFB-AA was 0.94 +/- 0.64 (range = 0.1-4.44) pmol mg(-1) albumin. Mean levels of vitamins A and E were 1.32 +/- 0.48 (range = 0.41-4.85) micromol l(-1) and 15.68 +/- 4.12 (range = 6.35-30.40) micromol l(-1), respectively. A significantly negative correlation was found between serum AFB-AA and vitamin A levels (r = -0.110, p = 0.013). An even stronger, significant negative, correlation was found between serum AFB-AA and vitamin E levels (r = -0.149, p < 0.001). Serum AFB-AA levels were statistically higher (median = 0.985 pmol mg(-1) albumin) in subjects who had low levels of both vitamins A and E as compared with the levels (median = 0.741 pmol mg(-1) albumin) subjects who had high vitamins A and E levels (p(trend) = 0.001). To verify these findings, blood samples were again collected from 165 of the 507 people 3 months after the initial collection. Significantly negative correlations were confirmed between levels of serum AFB-AA and both vitamins A (r = -0.232, p = 0.003) and E (r = -0.178, p = 0.023). Again, high serum AFB-AA concentrations (median = 1.578 pmol mg(-1) albumin) were found in subjects with low levels of vitamins A and E compared with the concentrations (median = 1.381 pmol mg(-1) albumin) in subjects with high levels of vitamins A and E (p(trend) = 0.002). These data show that AF exposure was associated with decreased levels of serum vitamins A and E in high-risk human populations, which may significantly influence the incidence of AF-related adverse health effects.

Relative age effect in youth soccer: analysis of the FIFA U17 World Cup competition

This investigation sought to determine if a relative age effect exists in the FIFA U17 World Cup competition. Birthdates of players competing in the most recent six competitions, from 1997 to 2007 were examined. For all competitions, the distributions of birth months were significantly different than expected with more players born in the early months of the year compared with the later months. For the entire cohort of players, 40% were born in the first quarter of the year while only 16% were born in the last 3 months. A small portion of this effect seems to be due to physical stature of the players. This relative age effect held for all FIFA-designated geographical zones except for Africa. The African region displayed a reverse relative age effect with a relatively large portion of players born in the later part of the year, particularly in December of the age appropriate year. The results of this investigation show that at the highest level of youth soccer, there is a strong bias toward inclusion of players born early in the selection year.

NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis: II. Reduction in biomarkers of aflatoxin exposure in blood and urine

The efficacy of NovaSil clay (NS) to reduce aflatoxin (AF) biomarkers of exposure was evaluated in 656 blood samples and 624 urine samples collected from study participants during a 3-month phase IIa clinical intervention trial in Ghana. NS was delivered before meals via capsules. Serum AFB (1)-albumin adduct was measured by radioimmunoassay and urinary AFM (1) metabolites were quantified by immunoaffinity-high-performance liquid chromatography (HPLC)-fluorescence methods. Levels of AFB (1) -albumin adduct in serum samples collected at baseline and at 1 month were similar (p = 0.2354 and p = 0.3645, respectively) among the placebo (PL), low dose (LD, 1.5 g NS day (-1)), and high dose (HD, 3.0 g NS day (-1)) groups. However, the levels of AFB (1)-albumin adduct at 3 months were significantly decreased in both the LD group (p < 0.0001) and the HD group (p < 0.0001) compared with levels in the PL group. Levels of AFM(1) in urine samples collected at baseline and at 1 month were not statistically different among the three study groups. However, a significant decrease (up to 58%) in the median level of AFM (1) in samples collected at 3 months was found in the HD group when compared with the median level in the PL group (p < 0.0391). In addition, significant effects were found for dose, time, and dose-time interaction with serum AFB(1)-albumin adduct and dose-time interaction with urinary AFM (1) metabolites. The results suggest that capsules containing NS clay can be used to reduce effectively the bioavailability of dietary AF based on a reduction of AF-specific biomarkers.

NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis. I. Study design and clinical outcomes

A 3-month double-blind and placebo-controlled, phase IIa clinical trial was conducted in Ghana to investigate the safety, tolerance and aflatoxin-sorption efficacy of dietary NovaSil (NS). Volunteers (507 subjects) were clinically screened to evaluate their general health, pregnancy status and blood AFB(1)-albumin adduct levels. Of these subjects, 177 were randomly assigned to three groups: high-dose (HD), low-dose (LD) and placebo-control (PL) groups receiving 3.0, 1.5 and 0 g NS day(-1) in capsules. Trained study-monitors supervised NS capsule administration to participants and recorded side-effects daily. Physical examinations were performed monthly. Blood and urine samples were collected for laboratory analysis. Approximately 92% of the participants (162 of 177) completed the study and compliance rate was over 97%. Overall, 99.5% of person x time reported no side-effects throughout the study. Mild to moderate health events ( approximately 0.5% of person x time) were recorded in some participants. Symptoms included nausea, diarrhea, heartburn and dizziness. These side-effects were statistically similar among all three groups. No significant differences were shown in hematology, liver and kidney function or electrolytes in the three groups. These findings demonstrate that NS clay is apparently safe and practical for the protection of humans against aflatoxins in populations at high risk for aflatoxicosis.

APOE alleles predict the rate of cognitive decline in Alzheimer disease: a nonlinear model

BACKGROUND

The APOE genotype predicts the age at onset of Alzheimer disease (AD) and neuropathologic progression. However, studies relating APOE alleles to the rate of cognitive decline have been inconclusive. This may stem from their use of linear statistical analyses.

OBJECTIVE

To model relations of APOE alleles to the rate of cognitive decline in AD, nonlinearly.

METHODS

Serial measures of cognitive ability were obtained using the cognitive scale of the Cambridge Examination for Mental Disorders of the Elderly in 218 patients with AD. The relations of these serial scores to APOE alleles were tested using nonlinear and linear mixed-effects models.

RESULTS

In the non-linear model, possession of an APOE epsilon4 allele related to earlier and faster cognitive decline, but possession of an APOE epsilon2 related to slower decline. Patients homozygous for APOE epsilon4 showed faster cognitive decline than heterozygotes. The linear model was less sensitive and did not detect differences between APOE epsilon4 homo- and heterozygotes.

CONCLUSIONS

APOE genotype strongly predicts the rate of cognitive decline in Alzheimer disease. The decline shows a dose-response relation with the APOE epsilon4 allele, but the APOE epsilon2 allele is protective. The nonlinear model yielded larger estimates of the maximal rate of decline than the linear.

Lymphangiosarcoma of dogs: a review

Lymphangiosarcoma in dogs, an extremely rare tumour with only 16 cases reported in the literature, is reviewed. Lymphangiosarcoma in humans, also very rare, and known in post-mastectomy, chronically-lymphoedematous patients as 'Stewart-Treves' syndrome, is briefly outlined, as well as the various other causes of lymphoedema, both primary and secondary, which usually precede malignancy. Comparisons between human and canine lymphoedema are made when such references were found. The genetic links to primary lymphoedema and the manifestation thereof in humans are mentioned. Lymphangiosarcoma in the majority of human and canine patients is an aggressively malignant tumour with few patients surviving despite various attempted treatments. The tumour most commonly arises in the subcutaneous tissues and rapidly invades underlying tissues and may spread widely internally via haematogenous and lymphatic routes, with frequent pleural and chest involvement. The tumour has been reported mostly in medium- to large-breed dogs, in slightly more males than females, and in an age-range of 8 weeks to 13 years, with more cases aged 5 years and older. Methods of diagnosis, with the variations encountered, including routine histopathology, immunohistochemistry, electron microscopy, tissue culture characteristics and endothelial expression of glycocongugates, are discussed.

Vertical cross contamination of trichloroethylene in a borehole in fractured sandstone

Boreholes drilled through contaminated zones in fractured rock create the potential for vertical movement of contaminated ground water between fractures. The usual assumption is that purging eliminates cross contamination; however, the results of a field study conducted in a trichloroethylene (TCE) plume in fractured sandstone with a mean matrix porosity of 13% demonstrates that matrix-diffusion effects can be strong and persistent. A deep borehole was drilled to 110 m below ground surface (mbgs) near a shallow bedrock well containing high TCE concentrations. The borehole was cored continuously to collect closely spaced samples of rock for analysis of TCE concentrations. Geophysical logging and flowmetering were conducted in the open borehole, and a removable multilevel monitoring system was installed to provide hydraulic-head and ground water samples from discrete fracture zones. The borehole was later reamed to complete a well screened from 89 to 100 mbgs; persistent TCE concentrations at this depth ranged from 2100 to 33,000 microg/L. Rock-core analyses, combined with the other types of borehole information, show that nearly all of this deep contamination was due to the lingering effects of the downward flow of dissolved TCE from shallower depths during the few days of open-hole conditions that existed prior to installation of the multilevel system. This study demonstrates that transfer of contaminant mass to the matrix by diffusion can cause severe cross contamination effects in sedimentary rocks, but these effects generally are not identified from information normally obtained in fractured-rock investigations, resulting in potential misinterpretation of site conditions.

Lymphangiosarcoma in a 3.5-year-old Bullmastiff bitch with vaginal prolapse, primary lymph node fibrosis and other congenital defects : clinical communication

Lymphangiosarcoma is an extremely rare tumour in dogs with only 16 cases reported in the literature. Lymphoedema, whichmaybe primary due to defects in the lymphatic system, or secondary to various other pathologies, often precedes malignancy. Of the 16 canine reports, only 1 dog was confirmed as having had prior primary lymphoedema due to aplasia of the popliteal lymph nodes. A case of lymphangiosarcoma is described in a 3.5-year-old purebred, Bullmastiff bitch which presented with vaginal blood 'spotting' for 3 weeks after cessation of oestrus, during which intromission by the male had been unsuccessful. During ovariohysterectomy a large multicystic, proliferative, spongy, fluid-filled, brownish-red mass surrounding the cervix and projecting into the abdominal space was removed with the cervix, and a diagnosis of lymphangiosarcoma made on histological and electron microscopic examination of the tissue. Ultrastructurally, no basement membrane or pericytes were found, only some of the neoplastic endothelial cells were linked by tight junctions while there were gaps between others, and neither micropinocytotic vesicles nor Weibel-Palade bodies occurred in the cells examined.Very few of the endothelial cells lining the many interlinking, tortuous maze of channels, stained slightly positive immunohistochemically for factor VIII-related antigen. The channels were filled mostly with serous fluid, and occasionally mixed leucocytes and some erythrocytes. The endothelium was often associated with underlying blocks of collagenous material, as well as looselyarranged aggregates of lymphocytes, other mononuclear cells and occasional neutrophils in the connective tissue septae and more prominently perivascularly. The bitch was discharged on antibiotic treatment but returned 2 weeks later with apparent prolapsed vagina which failed to reduce over the next week. Laparotomy revealed the tumour to have spread extensively in the caudal abdomen to involve the broad ligament and the ventral rectal serosa, and the 'prolapsed' tissue was found to be expanded vaginal wall. The bitch was euthanased and necropsied, Histological examination confirmed lymphangiosarcomatous invasion of the submucosal and muscular layers of the retroperitoneal, traumatised, prolapsed part of the vagina, the urethra and the ventral rectal wall. The broad ligament was diffusely invaded with tumour which had proliferated into the caudal abdominal space, and 3 small intra-trabecular foci of tumour were found in the right popliteal lymph node near the hilus. Mitotic figures were generally scarce. There was mild subcutaneous oedema of the ventral trunk extending from the axillae to the inner proximal thighs, which had not been evident clinically, and the lymph nodes (peripheral more so than internal) microscopically showed marked trabecular and perivascular fibrosis especially in hilar regions. Other congenital defects were hepatic capsular and central venous fibrosis with lymphatic duplication and dilatation in all areas of connective tissue, ventrally-incongruous half-circular tracheal rings, and multifocal renal dysplasia affecting the right kidney. There was locally-extensive subacute pyelonephritis of the left kidney.

Renal medullary AA amyloidosis, hepatocyte dissociation and multinucleated hepatocytes in a 14-year-old free-ranging lioness (Panthera leo)

A 14-year-old lioness, originating from Etosha in Namibia, and a member of a pride in Pilanesberg National Park since translocation in 1994, was euthanased due to fight-related vertebral fracture and spinal injury, incurred approximately 6-8 weeks previously. Blood specimens collected at the time of death showed mild anaemia and a leukogram reflecting stress and chronic infection. Necropsy conducted within 2 hours of death was on a dehydrated, emaciated animal with hindquarter wasting and chronic traumatic friction injuries from dragging her hindlegs. There was cellulitis in the region of bite-wounds adjacent to the thoraco-lumbar vertebral fracture, at which site there was spinal cord compression, and there was marked intestinal helminthiasis. The outer renal medullae appeared pale and waxy and the liver was macroscopically unremarkable. Histopathology and electron microscopy of the kidneys revealed multifocal to coalescing deposits of proximal medullary interstitial amyloid, which fluoresced strongly with thioflavine T, and was sensitive to potassium permanganate treatment prior to Congo Red staining, thus indicating inflammatory (AA) origin. There was diffuse hepatocyte dissociation, as well as numerous binucleated and scattered multinucleated (up to 8 nuclei/cell) hepatocytes, with swollen hepatocyte mitochondria, in liver examined light microscopically. Ultrastructurally, the mono-, bi- and multinucleated hepatocytes contained multifocal irregular membrane-bound accumulations of finely-granular, amorphous material both intra-cytoplasmically and intra-nuclearly, as well as evidence of irreversible mitochondrial injury. The incidence and relevance in cats and other species of amyloidosis, particularly with renal medullary distribution, as well as of hepatocyte dissociation and multinucleation, as reported in selected literature, is briefly overviewed and their occurrence in this lioness is discussed.

Glycogen debranching enzyme is associated with rat skeletal muscle sarcoplasmic reticulum

AIMS

Gel electrophoresis revealed a band of molecular weight approximately 160 000 Da associated with the skeletal muscle sarcoplasmic reticulum (SR) vesicle preparations. This investigation sought to examine glycogen debranching enzyme associated with skeletal muscle SR.

METHODS

Sarcoplasmic reticulum samples were also taken from muscle whose glycogen content had been reduced either via stimulation of the sciatic nerve or alpha-amylase treatment of muscle homogenates.

RESULTS

The stimulation protocol reduced whole muscle glycogen by 86% (7.4 +/- 0.4 vs. 1.0 +/- 0.3 microg mg(-1) wet mass, P < or = 0.05). Glycogen associated with the SR was reduced by 82% in the stimulation protocol (533 +/- 82 vs. 96 +/- 7 microg mg(-1) protein) and by 94% in alpha-amylase treatment (493 +/- 11 vs. 29 +/- 2 microg mg(-1) protein), respectively. Gel electrophoresis and Western blots revealed that the content of glycogen debranching enzyme was reduced by approximately 53% as a result of muscle stimulation and by approximately 46% in alpha-amylase treatment (P < or = 0.05). In addition, glycogen debranching enzyme activity was reduced by 61% in stimulated samples compared with control (20.3 +/- 1.0 vs. 8.0 +/- 1.2 nmol mg(-1) min(-1), respectively), a value consistent with reductions observed from gel electrophoresis and Western blots.

CONCLUSION

These results confirm that similar to glycogen phosphorylase, glycogen debranching enzyme is associated with the skeletal muscle SR and is dissociated under exercise conditions.

Effects of fatigue on depolarization- and caffeine-induced contractures of skinned fibres

AIMS

Fatigue has been shown to cause intrinsic alterations in sarcoplasmic reticulum (SR) Ca2+ release.

METHODS

In this investigation, frog semitendinosus muscles were stimulated to fatigue, in vitro (80 Hz, 100 ms, 1 train s-1, 5 min). Immediately after stimulation, single fibres were removed and skinned using either chemically or mechanically skinning. Contralateral muscle were treated similarly but were not stimulated.

RESULTS

In fatigued, saponin skinned fibres, contracture responses to low [caffeine] (4-8 mm) were depressed compared with control. However, responses to high concentrations (10-15 mm) were not different between conditions. In the fatigued, mechanically skinned fibres, responses to chloride depolarization were depressed at all [chloride] (20-100 mm) compared with control.

CONCLUSIONS

These results suggest that fatigue causes intrinsic alterations in both the SR Ca2+ release channel as well as communication between the transverse-tubule and the SR.

Comparison of formation and fluid-column logs in a heterogeneous basalt aquifer

Deep observation boreholes in the vicinity of active production wells in Honolulu, Hawaii, exhibit the anomalous condition that fluid-column electrical conductivity logs and apparent profiles of pore-water electrical conductivity derived from induction conductivity logs are nearly identical if a formation factor of 12.5 is assumed. This condition is documented in three boreholes where fluid-column logs clearly indicate the presence of strong borehole flow induced by withdrawal from partially penetrating water-supply wells. This result appears to contradict the basic principles of conductivity-log interpretation. Flow conditions in one of these boreholes was investigated in detail by obtaining flow profiles under two water production conditions using the electromagnetic flowmeter. The flow-log interpretation demonstrates that the fluid-column log resembles the induction log because the amount of inflow to the borehole increases systematically upward through the transition zone between deeper salt water and shallower fresh water. This condition allows the properties of the fluid column to approximate the properties of water entering the borehole as soon as the upflow stream encounters that producing zone. Because this condition occurs in all three boreholes investigated, the similarity of induction and fluid-column logs is probably not a coincidence, and may relate to aquifer response under the influence of pumping from production wells.

Neosporosis in a white rhinoceros (Ceratotherium simum) calf

A 16-day-old white rhinoceros calf died suddenly while in excellent condition and showing no obvious previous clinical signs. It was the 9th calf of a mature female kept free-ranging with 11 other rhinoceros as well as various other game species on a 2000 hectare game breeding centre adjacent to the town of Lichtenburg and outlying cattle farmlands in the Northern Province. At post mortem examination, death was ascribed to heart failure. There was marked multifocal to coalescing subacute parasitic myocarditis with numerous protozoan bradyzoite cysts and free tachyzoites present amongst the predominantly round cell inflammatory infiltrate. The coccidian was positively identified as Neospora sp. using both polyclonal and murine monoclonal Neospora caninum antibody immunohistochemistry in the avidin-biotin technique. The parasites stained poorly with Toxoplasma gondii-specific immunoperoxidase staining. Ultrastructurally, a section of a bradyzoite-containing cyst, as well as tachyzoites, were largely but not totally consistent with those described for Neospora caninum. The dam showed no sign of illness. Neosporosis affecting white rhinoceros (Ceratotherium simum) has not previously been reported. A summarised overview of neosporosis from selected publications and a recent review is given.

Action of deferoxamine against Pneumocystis carinii

We found earlier that deferoxamine (DFO), a drug used for treatment of iron overload, is active against a rat model of Pneumocystis carinii pneumonia (PCP). We had assumed a mode of action by deprivation of nutritional iron; however, data here show that DFO penetrates P. carinii, causing irreversible damage, thus indicating a different mode of action. Penetration was demonstrated by showing DFO uptake by high-pressure liquid chromatography analysis. By using calcein-AM as an indicator, exposure to DFO was shown to cause a reduction in P. carinii cytoplasmic free iron. Exposure to >or=100 microM DFO for >or=8 h in vitro caused growth to cease and cell numbers to decline over several days. This direct and irreversible damage to P. carinii led to the prediction that infrequent delivery of DFO to the lungs via an aerosol would be an effective treatment in the animal model of PCP. This prediction was confirmed by demonstrating that a once-a-week aerosol treatment of rats was 100% effective both as a prophylactic and as a curative treatment in a rat model of PCP.

The first reported case of equine nocardioform placentitis in South Africa

Since the late 1980s a distinct form of focally-extensive mucoid to mucopurulent uterine body chronic placentitis,caused by nocardioform organisms, hasbeen recognised in horses in the USA state of Kentucky and possibly in other areas. This disease has led to increasing numbers of foal losses from late abortions, still-births, prematurity, or early neonatal deaths. The foals are usually not infected, but may be small or emaciated. Modes of infection and transmission are as yet unknown. Nocardia spp. and related nocardioform bacteria as causes of equine infertility, endometritis and foal death are briefly reviewed. A case of near full-term abortion involving a Friesian mare in the Pretoria district of Gauteng Province in South Africa during February 2000, with the same placental lesion as described in the Kentucky cases, is presented. Nocardioform organisms were visualised on impression smears and histological sections of affected foetal membranes, and were also cultured. The organism has been identified at the Livestock Disease Diagnostic Center of the University of Kentucky as an Amycolatopsis sp. of the less-commonly diagnosed group of nocardioforms causing placentitis in the USA. The organism was cultured from the uterus of the mare 18 days post-foaling, but after a 2-week course of oral trimethoprim and sulphamethoxazole, based on antibiogram sensitivity testing, a uterine flush yielded no growth. A semen sample from the sire of the aborted foal did not yield any Gram-positive filamentous branching bacteria. The mare subsequently conceived to a single insemination.

Reproductive processes in two oak (Quercus) contact zones with different levels of hybridization

Patterns of reproductive isolation between two sympatric species of oaks, Quercus gambelii and Q. grisea, that exhibit strong ecological differentiation were examined. A full diallel cross using four trees of each species (i.e. all possible pollinations among eight trees) was performed. This design was repeated at two sites that represent different outcomes of sympatry: (1) a xeric mountain ridge where many hybrids are established (HZ); and (2) a mesic valley bottom where virtually no hybrids are established (MOCYN). By measuring fruit survival at several developmental stages, both the timing and strength of reproductive barriers within and between sites, species, cross types, and pollen dosage levels were examined. In three of four cases, heterospecific fruit set was significantly reduced compared to conspecific fruit set. This reduction occurred after the time of fertilization, but before the onset of embryo growth. Increasing the dose of pollen from an average of 9-194 grains/stigma did not affect this result. Thus, early postfertilization processes play a strong role in species fidelity in these oaks. Quercus gambelii experienced a five-fold decrease in conspecific fruit set at HZ relative to MOCYN. In contrast, heterospecific fruit set of Q. gambelii was the same at both sites. Poor Q. gambelii pollen performance is implicated as playing the major role in this result. One Q. gambelii individual at HZ was highly fecund, and had higher heterospecific than conspecific fruit set; slight introgression in this tree was detected uisng RAPD markers. The Environmental Emasculation Hypothesis that posits that environmental stress can increase the probability of hybrid formation by reducing the competitive ability of male gametes of one species is proposed.

Thyroid hormone receptor-interacting protein 1 modulates cytokine and nuclear hormone signaling in erythroid cells

Erythropoietin (Epo) and thyroid hormone (T(3)) are key molecules in the development of red blood cells. We have shown previously that the tyrosine kinase Lyn is involved in differentiation signals emanating from an activated erythropoietin receptor. Here we demonstrate that Lyn interacts with thyroid hormone receptor-interacting protein 1 (Trip-1), a transcriptional regulator associated with the T(3) receptor, providing a link between the Epo and T(3) signaling pathways. Trip-1 co-localized with Lyn and the T(3) receptor alpha in the cytoplasm/plasma membrane of erythroid cells but translocated to discrete nuclear foci shortly after Epo-induced differentiation. Our data reveal that T(3) stimulated the proliferation of immature erythroid cells, and inhibited maturation promoted by erythropoietin. Removal of T(3) reduced cell division and enhanced terminal differentiation. This was accompanied by large increases in the cell cycle inhibitor p27(Kip1) and by increasing expression of erythroid transcription factors GATA-1, EKLF, and NF-E2. Strikingly, a truncated Trip-1 inhibited both erythropoietin-induced maturation and T(3)-initiated cell division. This mutant Trip-1 acted in a dominant negative fashion by eliminating endogenous Lyn, elevating p27(Kip1), and blocking T(3) response elements. These data demonstrate that Trip-1 can simultaneously modulate responses involving both cytokine and nuclear receptors.

Glycogen and glycogen phosphorylase associated with sarcoplasmic reticulum: effects of fatiguing activity

The purpose of the present study was to investigate the effects of fatiguing muscular activity on glycogen, glycogen phosphorylase (GP), and Ca(2+) uptake associated with the sarcoplasmic reticulum (SR). Tetanic contractions (100 ms, 75 Hz) of the gastrocnemius and plantaris muscles, elicited once per second for 15 min, significantly reduced force to 26.5 +/- 4.0% and whole muscle glycogen to 23% of rested levels. SR glycogen levels were 415.4 +/- 76.6 and 20.4 +/- 2.1 microg/mg SR protein in rested and fatigued samples, respectively. The optical density of GP from SDS-PAGE was reduced to 21% of control, whereas pyridoxal 5'-phosphate concentration, a quantitative indicator of GP content, was significantly reduced to 3% of control. GP activity after exercise, in the direction of glycogen breakdown, was reduced to 4% of control. Maximum SR Ca(2+) uptake rate was also significantly reduced to 81% of control. These data demonstrate that glycogen and GP associated with skeletal muscle SR are reduced after fatiguing activity.

Homocysteine and cognitive decline in healthy elderly

Serum homocysteine is increased, and correlates inversely with cognitive scores, in Alzheimer's disease (AD), vascular dementia and "age-associated memory impairment". Elevated levels might signal accelerated cognitive decline, although this remains to be established. We therefore repeated Mini-Mental State Examinations, together with additional ADAS-Cog assessments, in 32 healthy elderly individuals to determine whether prior homocysteine levels predicted cognitive changes over a 5-year period. Homocysteine predicted follow-up cognitive scores and rate of decline in cognitive performance independently of age, sex, education, renal function, vitamin B status, smoking and hypertension (p < 0.001). Homocysteine predicted word recall (p = 0.01), orientation (p = 0.02) and constructional praxis scores (p < 0.0001). One subject, with the second highest initial homocysteine, had developed probable AD at follow-up. Fasting total serum homocysteine appears to be an independent predictor of cognitive decline in healthy elderly and exerts a maximal effect on spatial copying skills.

Correlates contributing to involvement in violent behaviors among young adults

The study examines the extent to which gender, personality attributes, household, community, and environmental factors are associated with violent behaviors in young adulthood. The authors present findings from a sample of 765 21-year-old individuals participating in a drug and delinquency prevention study. Personality attributes, opportunities, and social acceptability of antisocial behaviors were identified as accounting for gender differences and having more influence on violent behavior than environmental correlates. Implications for preventive intervention are discussed.

Diagnostic accuracy of 99Tcm-HIDA with cholecystokinin and gallbladder ejection fraction in acalculous gallbladder disease

The diagnostic accuracy and clinical impact of 99Tcm hepatic iminodiacetic acid (HIDA) imaging with cholecystokinin (CCK) was investigated in a prospective study of 359 patients over an 11 year period. All patients presented with right upper quadrant biliary type pain and had a normal ultrasound investigation prior to imaging. CCK was administered as a 3 min infusion at peak gallbladder uptake of HIDA. A gallbladder ejection fraction (GBEF) was used to quantify the gallbladder response to CCK. Two hundred and forty-four of 359 (68%) patients had an abnormal GBEF (< or = 35%). One hundred and thirty-four of 141 (95%) patients who underwent cholecystectomy had abnormal surgical/histological findings and/or relief of symptoms on long-term (mean 5.7 years) follow-up. Clinical follow-up, mean of 5.9 years, of the patients with GBEF > 35% showed 73/79 (92%) of them with little evidence of gallbladder disease. For a total 261 patients with mean clinical follow-up of 5.7 years the sensitivity of GBEF measurement is 95%, specificity is 92% and overall accuracy is 94%. It is concluded that 99Tcm-HIDA imaging, with a 3 min infusion of CCK, is a highly accurate technique and valuable in the diagnostic management of patients with suspected acalculous gallbladder disease.

Imitation, mirror neurons and autism

Various deficits in the cognitive functioning of people with autism have been documented in recent years but these provide only partial explanations for the condition. We focus instead on an imitative disturbance involving difficulties both in copying actions and in inhibiting more stereotyped mimicking, such as echolalia. A candidate for the neural basis of this disturbance may be found in a recently discovered class of neurons in frontal cortex, 'mirror neurons' (MNs). These neurons show activity in relation both to specific actions performed by self and matching actions performed by others, providing a potential bridge between minds. MN systems exist in primates without imitative and 'theory of mind' abilities and we suggest that in order for them to have become utilized to perform social cognitive functions, sophisticated cortical neuronal systems have evolved in which MNs function as key elements. Early developmental failures of MN systems are likely to result in a consequent cascade of developmental impairments characterised by the clinical syndrome of autism.

The central MHC gene, BAT1, may encode a protein that down-regulates cytokine production

BACKGROUND

BAT1 belongs to the DEAD-box family of RNA-binding proteins and is encoded in the central MHC. To determine whether it affects immune responses and hence diseases influenced by MHC haplotypes, U937, THP1 and Jurkat cells were stably transfected with anti-sense DNA corresponding to exons 2-5 of BAT1 using a retroviral vector.

RESULTS

Anti-sense transfectants carried anti-sense DNA and expressed anti-sense mRNA. After mitogenic stimulation, they produced higher levels of TNFalpha, IL-1 and IL-6 than equivalent cells carrying the vector alone, suggesting that BAT1 may down-regulate acute phase cytokine production. Polyclonal antibodies raised against a peptide in exon 8 of BAT1 recognized approximately 50 kDa and approximately 38 kDa proteins in all cell lines tested, including the anti-sense transfectants. Expression was localized to the nucleolus in dividing fibroblasts. However the immunochemistry may be confounded by a recently described gene, DDXL, on chromosome 19, which shares a 89% amino acid identity with BAT1. RT-PCR analyses established that BAT1 and DDXL mRNA are expressed in resting U937, THP1 and Jurkat cells. BAT1 and DDXL are divergent in the exons selected for the anti-sense study.

CONCLUSIONS

BAT1 is a negative regulator of inflammation. Future studies should address how its functions relate to those of DDXL.

Frequency-specific effects of flicker on recognition memory

The functions of the electroencephalographic rhythms are uncertain. Correlational evidence has linked 10-12Hz alpha rhythms to memory formation in healthy people. Moreover, loss of 10Hz alpha correlates with memory problems in Alzheimer's disease. Going beyond mere correlation, brain stimulation or peptides that alter electroencephalographic rhythms can modulate behaviour and enhance memory in rats. This latter finding fits with evidence that electroencephalogram-frequency stimulation can enhance long-term potentiation, the neural basis of memory. I aimed to test if manipulations of alpha-frequency electroencephalographic activity enhance human memory. Flicker provides an experimental means of modulating the human electroencephalogram: 9-12Hz flicker can entrain alpha-like activity. In rats, the frequency-specificity of brain stimulation's behavioural effects excludes the possibility that they result from non-specific (i.e. non-electroencephalographic) mechanisms. I tested if flicker manipulations would show analogous frequency-specific effects in man. In view of the above correlational data, I predicted that flicker at 10Hz (a frequency near to the peak power of endogenous alpha) would enhance human memory, but adjacent frequencies (8.7 and 11.7 Hz) would not. The results confirmed this prediction. This suggests that 10Hz electroencephalographic alpha subserves memory formation in man: 10Hz flicker enhances memory in healthy people and may have therapeutic potential in memory disorders.

Skeletal muscle calcineurin: influence of phenotype adaptation and atrophy

Calcineurin (CaN) has been implicated as a signaling molecule that can transduce physiological stimuli (e.g., contractile activity) into molecular signals that initiate slow-fiber phenotypic gene expression and muscle growth. To determine the influence of muscle phenotype and atrophy on CaN levels in muscle, the levels of soluble CaN in rat muscles of varying phenotype, as assessed by myosin heavy chain (MHC)-isoform proportions, were determined by Western blotting. CaN levels were significantly greater in the plantaris muscle containing predominantly fast (IIx and IIb) MHC isoforms, compared with the soleus (predominantly type I MHC) or vastus intermedius (VI, contains all 4 adult MHC isoforms). Three months after a complete spinal cord transection (ST), the CaN levels in the VI muscle were significantly reduced, despite a significant increase in fast MHC isoforms. Surprisingly, the levels of CaN in the VI were highly correlated with muscle mass but not MHC isoform proportions in ST and control rats. These data demonstrate that CaN levels in skeletal muscle are highly correlated to muscle mass and that the normal relationship with phenotype is lost after ST.

Maturation of erythroid cells and erythroleukemia development are affected by the kinase activity of Lyn

This study examined the impact of the tyrosine kinase Lyn on erythropoietin-induced intracellular signaling in erythroid cells. In J2E erythroleukemic cells, Lyn coimmunoprecipitated with numerous proteins, including SHP-1, SHP-2, ras-GTPase-activating protein, signal transducers and activators of transcription (STAT) 5a, STAT5b, and mitogen-activated protein kinase; however, introduction of a dominant-negative Lyn (Y397F Lyn) inhibited the interaction of Lyn with all of these molecules except SHP-1. Cells containing the dominant-negative Lyn displayed altered intracellular phosphorylation patterns, including mitogen-actiated protein kinase, but not erythropoietin receptor, Janus-activated kinase (JAK) 2, or STAT5. As a consequence, erythropoietin-initiated differentiation and basal proliferation were severely impaired. Y397F Lyn reduced the protein levels of erythroid transcription factors erythroid Kruppel-like factor and GATA-1 up to 90%, which accounts for the inability of J2E cells expressing Y397F Lyn to synthesize hemoglobin. Although Lyn was shown to bind several sites on the cytoplasmic domain of the erythropoietin receptor, it was not activated when a receptor mutated at the JAK2 binding site was ectopically expressed in J2E cells indicating that JAK2 is the primary kinase in erythropoietin signaling and that Lyn is a secondary kinase. In normal erythroid progenitors, erythropoietin enhanced phosphorylation of Lyn; moreover, exogenous Lyn increased colony forming unit-erythroid, but not burst forming uniterythroid, colonies from normal progenitors, demonstrating a stage-specific effect of the kinase. Significantly, altering Lyn activity in J2E cells had a profound effect on the development of erythroleukemias in vivo: the mortality rate was markedly reduced and latent period extended when either wild-type Lyn or Y397F Lyn was introduced into these cells. Taken together, these data show that Lyn plays an important role in intracellular signaling in nontransformed and leukemic erythroid cells.

Osteoprotegerin is produced when prostaglandin synthesis is inhibited causing osteoclasts to detach from the surface of mouse parietal bone and attach to the endocranial membrane

Osteoclast differentiation and activation is controlled, at least in part, by the counterbalancing influences of osteoprotegerin ligand (OPGL) and osteoprotegerin (OPG). Nonsteroidal anti-inflammatory drugs have been shown to inhibit bone loss in vivo and bone resorption in vitro, and this is associated with a loss of osteoclasts from the bone surface. We test the hypothesis that OPG mediates the inhibition of osteoclast activity that occurs with indomethacin in the mouse calvaria. Recombinant human OPG, like indomethacin, was found to cause osteoclasts to detach from the bone surface and attach to the adjacent endocranial membrane (periosteum). Recombinant human OPG also inhibited the stimulatory effect of prostaglandin E2 (PGE2), parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D3 (1,25D3) on osteoclast adhesion to bone after an incubation with indomethacin. A function-blocking antibody to OPG and soluble human OPGL both inhibited the effect of indomethacin, leaving active osteoclasts on the bone. OPG activity was detected in the culture medium from indomethacin-treated bones and PTH, PGE2, 1,25D3, and dexamethasone all inhibited the production of OPG activity. We conclude that, in the absence of specific stimulators of bone resorption, OPG is produced by the mouse calvaria in vitro, which inhibits bone resorption by causing osteoclasts to detach from the bone surface.