New approach methodologies to enhance human health risk assessment of immunotoxic properties of chemicals - a PARC (Partnership for the Assessment of Risk from Chemicals) project

As a complex system governing and interconnecting numerous functions within the human body, the immune system is unsurprisingly susceptible to the impact of toxic chemicals. Toxicants can influence the immune system through a multitude of mechanisms, resulting in immunosuppression, hypersensitivity, increased risk of autoimmune diseases and cancer development. At present, the regulatory assessment of the immunotoxicity of chemicals relies heavily on rodent models and a limited number of Organisation for Economic Co-operation and Development (OECD) test guidelines, which only capture a fraction of potential toxic properties. Due to this limitation, various authorities, including the World Health Organization and the European Food Safety Authority have highlighted the need for the development of novel approaches without the use of animals for immunotoxicity testing of chemicals. In this paper, we present a concise overview of ongoing efforts dedicated to developing and standardizing methodologies for a comprehensive characterization of the immunotoxic effects of chemicals, which are performed under the EU-funded Partnership for the Assessment of Risk from Chemicals (PARC).

Comprehensive mapping of the AOP-Wiki database: identifying biological and disease gaps

Introduction: The Adverse Outcome Pathway (AOP) concept facilitates rapid hazard assessment for human health risks. AOPs are constantly evolving, their number is growing, and they are referenced in the AOP-Wiki database, which is supported by the OECD. Here, we present a study that aims at identifying well-defined biological areas, as well as gaps within the AOP-Wiki for future research needs. It does not intend to provide a systematic and comprehensive summary of the available literature on AOPs but summarizes and maps biological knowledge and diseases represented by the already developed AOPs (with OECD endorsed status or under validation). Methods: Knowledge from the AOP-Wiki database were extracted and prepared for analysis using a multi-step procedure. An automatic mapping of the existing information on AOPs (i.e., genes/proteins and diseases) was performed using bioinformatics tools (i.e., overrepresentation analysis using Gene Ontology and DisGeNET), allowing both the classification of AOPs and the development of AOP networks (AOPN). Results: AOPs related to diseases of the genitourinary system, neoplasms and developmental anomalies are the most frequently investigated on the AOP-Wiki. An evaluation of the three priority cases (i.e., immunotoxicity and non-genotoxic carcinogenesis, endocrine and metabolic disruption, and developmental and adult neurotoxicity) of the EU-funded PARC project (Partnership for the Risk Assessment of Chemicals) are presented. These were used to highlight under- and over-represented adverse outcomes and to identify and prioritize gaps for further research. Discussion: These results contribute to a more comprehensive understanding of the adverse effects associated with the molecular events in AOPs, and aid in refining risk assessment for stressors and mitigation strategies. Moreover, the FAIRness (i.e., data which meets principles of findability, accessibility, interoperability, and reusability (FAIR)) of the AOPs appears to be an important consideration for further development.

Hazard characterization of Alternaria toxins to identify data gaps and improve risk assessment for human health

Fungi of the genus Alternaria are ubiquitous plant pathogens and saprophytes which are able to grow under varying temperature and moisture conditions as well as on a large range of substrates. A spectrum of structurally diverse secondary metabolites with toxic potential has been identified, but occurrence and relative proportion of the different metabolites in complex mixtures depend on strain, substrate, and growth conditions. This review compiles the available knowledge on hazard identification and characterization of Alternaria toxins. Alternariol (AOH), its monomethylether AME and the perylene quinones altertoxin I (ATX-I), ATX-II, ATX-III, alterperylenol (ALP), and stemphyltoxin III (STTX-III) showed in vitro genotoxic and mutagenic properties. Of all identified Alternaria toxins, the epoxide-bearing analogs ATX-II, ATX-III, and STTX-III show the highest cytotoxic, genotoxic, and mutagenic potential in vitro. Under hormone-sensitive conditions, AOH and AME act as moderate xenoestrogens, but in silico modeling predicts further Alternaria toxins as potential estrogenic factors. Recent studies indicate also an immunosuppressive role of AOH and ATX-II; however, no data are available for the majority of Alternaria toxins. Overall, hazard characterization of Alternaria toxins focused, so far, primarily on the commercially available dibenzo-α-pyrones AOH and AME and tenuazonic acid (TeA). Limited data sets are available for altersetin (ALS), altenuene (ALT), and tentoxin (TEN). The occurrence and toxicological relevance of perylene quinone-based Alternaria toxins still remain to be fully elucidated. We identified data gaps on hazard identification and characterization crucial to improve risk assessment of Alternaria mycotoxins for consumers and occupationally exposed workers.

Mesenchyme-derived IGF2 is a major paracrine regulator of pancreatic growth and function

The genetic mechanisms that determine the size of the adult pancreas are poorly understood. Imprinted genes, which are expressed in a parent-of-origin-specific manner, are known to have important roles in development, growth and metabolism. However, our knowledge regarding their roles in the control of pancreatic growth and function remains limited. Here we show that many imprinted genes are highly expressed in pancreatic mesenchyme-derived cells and explore the role of the paternally-expressed insulin-like growth factor 2 (Igf2) gene in mesenchymal and epithelial pancreatic lineages using a newly developed conditional Igf2 mouse model. Mesenchyme-specific Igf2 deletion results in acinar and beta-cell hypoplasia, postnatal whole-body growth restriction and maternal glucose intolerance during pregnancy, suggesting that the mesenchyme is a developmental reservoir of IGF2 used for paracrine signalling. The unique actions of mesenchymal IGF2 are demonstrated by the absence of any discernible growth or functional phenotypes upon Igf2 deletion in the developing pancreatic epithelium. Additionally, increased IGF2 levels specifically in the mesenchyme, through conditional Igf2 loss-of-imprinting or Igf2r deletion, leads to pancreatic acinar overgrowth. Furthermore, ex-vivo exposure of primary acinar cells to exogenous IGF2 activates AKT, a key signalling node, and increases their number and amylase production. Based on these findings, we propose that mesenchymal Igf2, and perhaps other imprinted genes, are key developmental regulators of adult pancreas size and function.

Daily Fermented Whey Consumption Alters the Fecal Short-Chain Fatty Acid Profile in Healthy Adults

Gut microbiota influences many aspects of host health including immune, metabolic, and gut health. We examined the effect of a fermented whey concentrate (FWC) drink rich in L-(+)-Lactic acid, consumed daily, in 18 healthy men (n = 5) and women (n = 13) in free-living conditions.

Objective: The aims of this 6-weeks pilot trial were to (i) identify changes in the gut microbiota composition and fecal short chain fatty acid (SCFA) profile, and (ii) to monitor changes in glucose homeostasis.

Results: Total fecal SCFA (mM) concentration remained constant throughout the intervention. Proportionally, there was a significant change in the composition of different SCFAs compared to baseline. Acetate levels were significantly reduced (−6.5%; p < 0.01), coupled to a significant increase in the relative amounts of propionate (+2.2%; p < 0.01) and butyrate (+4.2%; p < 0.01), respectively. No changes in the relative abundance of any specific bacteria were detected. No significant changes were observed in glucose homeostasis in response to an oral glucose tolerance test.

Conclusion: Daily consumption of a fermented whey product led to significant changes in fecal SCFA metabolite profile, indicating some potential prebiotic activity. These changes did not result in any detectable differences in microbiota composition. Post-hoc analysis indicated that baseline microbiota composition might be indicative of participants likely to see changes in SCFA levels. However, due to the lack of a control group these findings would need to be verified in a rigorously controlled trial. Future work is also required to identify the biological mechanisms underlying the observed changes in microbiota activity and to explore if these processes can be harnessed to favorably impact host health.

Clinical Trial Registration: www.clinicaltrials.gov, identifier NCT03615339; retrospectively registered on 03/08/2018.

In pursuit of the triple crown: mechanism-based pharmacodynamic modelling for the optimization of three-drug combinations against KPC-producing Klebsiella pneumoniae

OBJECTIVES

Optimal combination therapy for Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-Kp) is unknown. The present study sought to characterize the pharmacodynamics (PD) of polymyxin B (PMB), meropenem (MEM) and rifampin (RIF) alone and in combination using a hollow fibre infection model (HFIM) coupled with mechanism-based modelling (MBM).

METHODS

A 10-day HFIM was utilized to simulate human pharmacokinetics (PK) of various PMB, MEM and RIF dosing regimens against a clinical KPC-Kp isolate, with total and resistant subpopulations quantified to capture PD response. A MBM was developed to characterize bacterial subpopulations and synergy between agents. Simulations using the MBM and published population PK models were employed to forecast the bacterial time course and the extent of its variability in infected patients for three-drug regimens.

RESULTS

In the HFIM, a PMB single-dose ('burst') regimen of 5.53 mg/kg combined with MEM 8 g using a 3-hr prolonged infusion every 8 hr and RIF 600 mg every 24 hr resulted in bacterial counts below the quantitative limit within 24 hr and remained undetectable throughout the 10-day experiment. The final MBM consisted of two bacterial subpopulations of differing PMB and MEM joint susceptibility and the ability to form a non-replicating, tolerant subpopulation. Synergistic interactions between PMB, MEM and RIF were well quantified, with the MBM providing adequate capture of the observed data.

DISCUSSION

An in vitro-in silico approach answers questions related to PD optimization as well as overall feasibility of combination therapy against KPC-Kp, offering crucial insights in the absence of clinical trials.

Chloroform-Methanol Extraction Method for Determination of Fat in Foods: Collaborative Study

Achloroform-methanol extraction method (complete extraction of fat in 3 min) for determining fat in processed and prepared foods has been studied collaboratively. Fourteen collaborators reported single replicate fat results on 7 samples representative of various food types and 2 spiked samples by the proposed method. Each sample was accompanied by a blind duplicate. For statistical purposes, the blind duplicates were treated as paired observations, and there were 2 laboratory outliers. There was a 97.9% agreement among the results from the remaining 12 collaborators and the Associate Referee for the unfortified samples. Recoveries of 93.8 and 98.3% were obtained on fortified samples, based on results obtained from 11 collaborators. The statistical analysis of the results indicate (ranges for standard deviations were Sr = 0.083-0.528, Sb = 0.101-0.379, Sd = 8.130-0.631, for fat values ranging from 1.58 to 26.91%) that this method is adequate for quantitating the fat content in a wide variety of processed foods for nutritional labeling. The method has been adopted official first action.

Enabling dual cellular destinations of polymeric nanoparticles for treatment following partial injury to the central nervous system

Following neurotrauma, oxidative stress is spread via the astrocytic syncytium and is associated with increased aquaporin 4 (AQP4), inflammatory cell infiltration, loss of neurons and glia and functional deficits. Herein we evaluate multimodal polymeric nanoparticles functionalized with an antibody to an extracellular epitope of AQP4, for targeted delivery of an anti-oxidant as a therapeutic strategy following partial optic nerve transection. Using fluorescence microscopy, spectrophotometry, correlative nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy, in vitro and in vivo, we demonstrate that functionalized nanoparticles are coated with serum proteins such as albumin and enter both macrophages and astrocytes when administered to the site of a partial optic nerve transection in rat. Antibody functionalized nanoparticles synthesized to deliver the antioxidant resveratrol are effective in reducing oxidative damage to DNA, AQP4 immunoreactivity and preserving visual function. Non-functionalized nanoparticles evade macrophages more effectively and are found more diffusely, including in astrocytes, however they do not preserve the optic nerve from oxidative damage or functional loss following injury. Our study highlights the need to comprehensively investigate nanoparticle location, interactions and effects, both in vitro and in vivo, in order to fully understand functional outcomes.

A microfluidic platform to synthesize a G-quadruplex binding ligand

An aromatic triarylpyridine chromophore promotes pi-stacking interactions with the terminal G-tetrad in quadruplex DNA, stabilizing the structure and presenting a pathway towards cancer treatment by inhibition of telomerase. An interesting parent compound in this class is the dimethylamino functionalised 4'-aryl-2,6-bis(4-aminophenyl)pyridine. However, access to this compound using traditional batch synthetic methodology is limited, due to thermodynamic and kinetic constraints. A novel approach to the synthesis of this compound has been developed, involving dynamic thin films, overcoming a series of competing reactions, effectively controlling chemical reactivity and selectivity.

Phosphate uptake in chick kidney cells: effects of 1,25(OH)2D3 and 24,25(OH)2D3

Phosphate homeostasis is controlled in part by absorption from the intestine, and reabsorption in the kidney. While the effect of Vitamin D metabolites on enterocytes is well documented, in the current study we assess selected responses in primary cultures of kidney cells. Time course studies revealed a rapid stimulation of phosphate uptake in cells treated with 1,25(OH)(2)D(3), relative to controls. Dose-response studies indicated a biphasic curve with optimal stimulation at 300 pM 1,25(OH)(2)D(3) and inhibition at 600 pM seco-steroid. Antibody 099--against the 1,25D(3)-MARRS receptor - abolished stimulation by the steroid hormone. Moreover, phosphate uptake was mediated by the protein kinase C pathway. The metabolite 24,25(OH)(2)D(3), which was found to inhibit the rapid stimulation of phosphate uptake in intestinal cells, had a parallel effect in cultured kidney cells. Finally, the 24,25(OH)(2)D(3) binding protein, catalase, was assessed for longer term down regulation. In both intestinal epithelial cells and kidney cells incubated with 24,25(OH)(2)D(3) for 5-24h, both the specific activity of the enzyme and protein levels were decreased relative to controls, while 1,25(OH)(2)D(3) increased both parameters over the same time periods. We conclude that the Vitamin D metabolites have similar effects in both kidney and intestine, and that 24,25(OH)(2)D(3) may have effects at the level of gene expression.

Rapidly increasing prevalence of eosinophilic oesophagitis in Western Australia

AIM

To assess the prevalence of eosinophilic oesophagitis in a tertiary paediatric gastroenterology clinic population.

METHODS

A retrospective audit of Western Australian children investigated for oesophageal disease by paediatric gastroenterologists in the years 1995, 1999 and 2004. Macroscopic appearance of the oesophagus at endoscopy, original histological findings and diagnosis were recorded for each child. Biopsy specimens were blindly re-evaluated, with re-coded histological diagnoses compared with original reports. Age, sex and socioeconomic status were identified for each child.

RESULTS

The prevalence of eosinophilic oesophagitis in Western Australia increased over the decade 1995-2004, rising from 0.05 to 0.89 per 10 000 children, with a concomitant increase in the severity of oesophagitis as determined by inflammatory cell numbers and associated features of inflammation. Children diagnosed with eosinophilic oesophagitis had a median age of 78.9 months (6.58 years), with no associated predisposition by sex or socioeconomic status trend. Almost one third of cases were macroscopically normal at endoscopy. All children with an original diagnosis of eosinophilic oesophagitis had > or =40 eosinophils per high-power field.

CONCLUSION

Over the decade 1995-2004, a true increase was seen in the prevalence of eosinophilic oesophagitis, not accounted for by diagnostic shift. Histological samples should be taken at endoscopy to confirm or exclude the diagnosis of eosinophilic oesophagitis.

The reliability and validity of the physiological cost index in healthy subjects while walking on 2 different tracks

OBJECTIVE

To investigate the reliability and validity of the Physiological Cost Index (PCI) scores, as a measure of energy expenditure, when healthy subjects walk on 2 different tracks (20-m and 12-m figure eight tracks).

DESIGN

Intra- and interrater reliability and construct validity.

SETTING

Physiotherapy division of a university in London, UK.

PARTICIPANTS

Forty healthy subjects (15 men, 25 women; mean age +/- standard deviation, 34.5+/-12.6 y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Heart rate (in beats/min) and speed (in m/min) were used to calculate the PCI (in beats/m). Rate of oxygen consumption (VO2, in mL x kg(-1) x min(-1)) and oxygen cost (EO2, in mL x kg(-1) x m(-1)) were used as criterion estimates of energy cost EO2. Pearson correlation coefficients between the PCI, components of the PCI, EO2, and VO2 were used to quantify validity. Intrarater reliability was assessed in all participants and interrater reliability was assessed on a subset of 13 subjects using intraclass correlation coefficients and Bland-Altman plots.

RESULTS

Intrarater (r=.73, r=.79) and interrater (r=.62, r=.66) reliability were acceptable between PCI scores from 20-m and 12-m tracks, respectively. Correlations between VO2 and EO2 with PCI were weak. PCI scores from the 20-m track were significantly lower than those on the 12-m track (P=.002). Subjects walked significantly faster on the 20-m track (P<.001). Results suggest a large difference in PCI scores would be necessary to indicate a "true" alteration in performance (52% for 20-m track, 43.4% for the 12-m track).

CONCLUSIONS

The PCI is reliable but not valid as a measure of the energy cost of walking in healthy subjects, on either track. The 20-m track is recommended for clinical use because it enables subjects to walk at a faster pace.

The use of complementary medicines by those with asthma

Complementary therapies attract considerable media attention and previous surveys of members of an asthma patient organisation suggested that their use by those with asthma was commonplace. This report concerns a study of a stratified cross section of the asthma population designed to give a more representative insight into current usage of complementary therapies. A sift questionnaire was used to identify those with asthma and 785 of those so identified undertook a semi-structured face-to-face interview. Only 6% of the study population were current users of complementary therapies with use being more common amongst those who expressed most concern regarding their current medication. Low use of complementary therapies may well reflect satisfaction with current management and suggests that previous surveys may have been unrepresentative of a more balanced population of those with asthma.

The role of the pathologist in the management of neuroblastoma

The role of the pathologist in the management of neuroblastoma, in the context of the team approach to these lesions, is discussed. The importance of the provision of fresh material is stressed, and the prognostic importance of histology and ancillary tests is noted. Participation by the team in a children's cancer study group is a vital component of current and future treatment methods.

The effects of overcoming experimental bladder outflow obstruction in fetal sheep

OBJECTIVE

To develop an ovine model of fetal bladder outflow obstruction and to investigate the effect on the kidney of surgical relief of the obstruction in the prenatal period.

METHODS

Ultrasound examination and amniocentesis were performed on 68 date-bred pregnant ewes at day 57 of pregnancy (term = 150 days). Fetal gender was determined using a molecular technique to identify single male fetuses. The urethra and urachus were ligated at hysterotomy on 20 of these fetuses at 75 days' gestation. Comparisons were made with six controls that did not undergo operation. Changes that occurred in fetal urinary tract appearance were detected using serial ultrasound examinations. Seven obstructed cases chosen at random had further prenatal surgery on day 94 to decompress the obstructed urinary tract by vesicostomy. The animals were killed at 110 days' gestation and post-mortem studies were performed.

RESULTS

Fourteen days after surgical obstruction, there were increases in the summed renal lengths (33 mm vs. 28 mm, p = 0.003) and renal pelvis anteroposterior (A-P) diameters (8 mm vs. 5.5 mm, p = 0.02). In the group allocated to receive surgical decompression, 9 days' relief of obstruction resulted in significant reductions in summed renal lengths (30 mm vs. 41 mm, p = 0.024; controls 31 mm) and renal pelvis A-P diameters (5.8 mm vs. 8.9 mm, p = 0.012; controls < 2 mm). Postmortem histological examination in the surgical decompression group revealed an estimated number of glomeruli similar to controls and greater than in the obstructed cases.

CONCLUSION

Surgical relief of fetal bladder outflow obstruction in ovine mid-pregnancy results in improved renal appearance on ultrasonic and histopathological examinations.

Lethal X-linked microcephaly with dysmorphic features, bilateral optic pathway aplasia and normal eyes

We describe a family, consisting of two brothers and a maternal uncle who died of an apparently identical condition, within a few days of birth, suggestive of an X-linked mode of inheritance. The propositus (the older sibling) was investigated in detail and showed the following clinical features: microcephaly, facial dysmorphism, malformations of hands and feet, and cryptorchidism. Examination of the brain revealed arhinencephaly, a primitive gyral pattern, arrested cortical maturation, absence of corticofugal tracts and corpus callosum, agenesis of the optic pathway with preserved eyes and oculomotor system, absent auditory pathway, agenesis of the pars compacta of the substantia nigra and severe hypoplasia of the cerebellum and its connections. This family belongs to the group of X-linked microcephalies and has some features in common with the Juberg-Marsidi syndrome. The fact that the CNS abnormalities were incompatible with life and the facial dysmorphic features were quite different makes it unlikely that the affected individuals in this family had Juberg-Marsidi syndrome. However, this does not exclude the possibility that more restricted anterior induction defects may occur in some X-linked microcephalies such as Juberg-Marsidi syndrome resulting in prolonged survival.

Prothrombotic megakaryocyte and platelet changes in hypertension are reversed following treatment: a pilot study

Platelets are formed from, and their function determined by, bone marrow megakaryocytes (MK). Previous studies have found that hypertension is associated with accentuated platelet function and that some antihypertensive drug classes have antiplatelet activity. We measured MK ploidy (DNA content), size, granularity, and expression of the adhesion molecule glycoprotein (GP) IIIa, using flow cytometry and measures of platelet function, in 12 untreated hypertensive patients and 14 normotensive subjects. Eight hypertensive patients were then treated with losartan (50 mg daily), an angiotensin receptor antagonist that lowers blood pressure, and MK and platelet parameters re-measured after 6 weeks. Hypertensive patients had, as compared with matched normotensive subjects: increased MK ploidy (mean +/- SD) 22.9 +/- 2.2 N versus 20.8 +/- 1.6 N (2P = 0.009); increased platelet size, 10.67 +/- 1.03fl versus 9.26 +/- 0.72fl (2P < 0.001); increased platelet expression of GP IIIa, 108.6 +/- 22.5 versus 92.0 +/- 12.3 (2P = 0.036); and reduced platelet count, (207 +/- 52) x 10(9)/l versus (257 +/- 55) x 10(9)/l (2P = 0.026). Losartan significantly reduced MK ploidy, 22.6 +/- 2.2 N versus 21.4 +/- 1.9 N (2P = 0.006); MK size, 607 +/- 22 versus 579 +/- 16 (2P = 0.003); and lengthened cutaneous bleeding time, 424 +/- 86s versus 563 +/- 164s (2P = 0.011), in hypertensive patients. Losartan did not alter MK granularity or GP IIIa expression, or platelet count, size, mass, GP IIIa expression, or aggregation. The data suggest that platelet changes in hypertension may be secondary to changes in MKs, and that anti-hypertensive treatment can alter MKs and the function of platelets they produce. Since antihypertensive therapy reduces the risk of stroke and myocardial infarction, MKs are a novel therapeutic target for the prevention of vascular events.

Protein solubility and folding monitored in vivo by structural complementation of a genetic marker protein

Protein misfolding is the basis of a number of human diseases and presents an obstacle to the production of soluble recombinant proteins. We present a general method to assess the solubility and folding of proteins in vivo. The basis of this assay is structural complementation between the alpha- and omega- fragments of beta-galactosidase (beta-gal). Fusions of the alpha-fragment to the C terminus of target proteins with widely varying in vivo folding yield and/or solubility levels, including the Alzheimer's amyloid beta (A beta) peptide and a non-amyloidogenic mutant thereof, reveal an unambiguous correlation between beta-gal activity and the solubility/folding of the target. Thus, structural complementation provides a means of monitoring protein solubility/misfolding in vivo, and should find utility in the screening for compounds that influence the pathological consequences of these processes.

Broadsheet number 56: Mechanisms of fetal loss

The most significant task of the pathologist examining a fetal death is, if possible, the provision of an explanation for the event, which will allow the clinical attendants to counsel the family in an informed and relevant manner. In some cases, no adequate explanation will be possible, though many conditions will be excluded and the importance of this exercise is worth emphasising. Often, however, a combination of fetal, maternal or placental conditions can be found and a full or partial explanation offered, and it is the purpose of this broadsheet to highlight some of these conditions and provide suggestions as to sources of further practical help.

Unexpected childhood death due to hemolytic uremic syndrome

Two cases of unexpected childhood death due to hemolytic uremic syndrome are reported. A 21-month-old girl who was discovered dead in bed following a short illness was found at autopsy to have overwhelming sepsis resulting from transmural colitis. Escherichia coli serotype 0157A was isolated from the intestine, and renal changes of hemolytic uremic syndrome were found. A 4-year-old girl died suddenly in hospital from intracranial hemorrhage while being treated for hemolytic uremic syndrome-related renal failure. Culture of urine and feces grew verocytotoxin producing E. coli. These cases demonstrate that hemolytic uremic syndrome may be a rare cause of unexpected childhood death and that the diagnosis may not be established prior to autopsy. Postmortem culture of tissues and fluids in cases of suspected sepsis in children may be essential in establishing this diagnosis, because histologic evaluation may be compromised by profound sepsis and tissue putrefaction. Accuracy in diagnosis may have significant public health and medicolegal consequences.

Platelets and stroke

Platelets are anucleate cells with little or no capacity for de novo protein synthesis. Their potential haemostatic reactivity is established at or before thrombopoiesis by their precursor cell, the bone marrow megakaryocyte. In some pathologic conditions, the megakaryocyte-platelet-haemostatic axis (MPHA) becomes perturbed, resulting in the formation of hyperfunctional platelets which may contribute to the development of vascular disease or an acute thrombotic event such as ischaemic stroke or myocardial infarction. Laboratory measurements of platelet function have established that platelet reactivity is accentuated in acute ischaemic stroke, particularly following cortical rather than lacunar infarction. Whether accentuated platelet function is a cause or a consequence of stroke is not yet clear, but it is likely that patients with certain risk factor profiles have some degree of platelet activation preceding the stroke. Further work into the MPHA is required to establish whether enhanced post-stroke platelet reactivity can be referred to the megakaryocyte. The antiplatelet agents tested to date are effective in secondary but not primary prevention of stroke. This probably reflects the diverse pathophysiology of stroke: accentuated platelet function is only likely to be a significant factor in cortical stroke.

Bilateral Wilms' tumor: a clinicopathologic review

Bilateral Wilms' tumor occurs at a younger age than unilateral disease. While it generally has a good prognosis, it presents a therapeutic dilemma to balance curative surgical resection with preservation of renal tissue. A 15 year review of bilateral Wilms' tumors diagnosed at Princess Margaret Hospital was undertaken. Of 46 Wilms' tumor cases, eight were designated bilateral by diagnostic imaging (median age 1.1 years compared with 3.5 years for unilateral tumors). The surgical management entailed primary nephrectomy with contralateral biopsy in two patients, and bilateral biopsy and delayed resection in all remaining surviving patients (one patient died of perioperative complications). Seven patients had localized disease (stage I/II) and the six surviving patients received chemotherapy with vincristine and actinomycin; no patient received radiotherapy. All are alive and well (median follow-up 5.1 years). The remaining patient presented with pulmonary metastases and died of disease progression. Pathologic review revealed that four patients had truly bilateral disease demonstrable by histology, three had unilateral Wilms' tumor with contralateral nephrogenic rests, and in one patient the biopsies of the contralateral kidney showed neither tumor nor nephrogenic rests. In most cases pathological material was subject to external review. Follow-up demonstrates excellent renal function with compensatory hypertrophy in the remaining renal tissue. Conservative surgery and simple out-patient based, low toxicity chemotherapy is curative in most patients.

Atypical mycobacterial lymphadenitis in childhood--a clinicopathological study of 17 cases

AIMS

To assess the clinical and pathological features of atypical mycobacterial lymphadenitis in childhood to define the salient clinical and histological features.

METHODS

17 cases were included on the basis of positive culture or demonstration of bacilli of appropriate morphology and staining characteristics.

RESULTS

The mean age at diagnosis was 4.86 years. All children were systemically well, with clear chest x rays. Unilateral cervical lymphadenopathy was the commonest mode of presentation. Differential Mantoux testing played no part in diagnosis. Clinical diagnosis improved with awareness. Treatment varied with surgeons opting for excision and paediatricians adding six months antituberculous chemotherapy. Acid- and alcohol-fast bacilli were identified in nine cases. Bacterial cultures were conducted in 16 cases and were positive for atypical or nontuberculous mycobacteria in 14, the main organism being M avium-intracellulare complex (11 cases). Histologically, 12 cases had bright eosinophilic serpiginous necrosis with nuclear debris scattered throughout the necrotic foci. Langhans type giant cells featured in the majority of cases but infiltration by plasma cells and neutrophils was not consistent.

CONCLUSIONS

Atypical mycobacterial lymphadenitis of childhood represents a rare but significant disease with characteristic clinical and histological features.

Medullary ray nodule of the kidney

In this short report we describe three preterm infants who died within the first 8 months of life (corrected age). All presented similar histological features within the kidney, showing medullary ray nodules composed of tubules lined by low columnar epithelium with clear cytoplasm. The immunohistochemical profile of these lesions was identical and suggested origin from distal convoluted tubule or collecting duct. The aim of this report is to draw attention to this entity and to suggest a possible origin of these lesions.

Cytogenetics of an atypical Spitz nevus metastatic to a single lymph node

Clinicopathologic details of an atypical Spitz nevus are reported. A metastasis to a single ipsilateral lymph node is documented. Cytogenetic analysis of the metastatic lesion revealed a clonal chromosomal abnormality, add(6)(q12-13), previously noted in cases of malignant melanoma.

Detection of respiratory syncytial virus nucleic acid in archival postmortem tissue from infants

Archival lung tissue from 99 cases of sudden infant death syndrome (SIDS) and from 58 matched comparison cases with known causes of death was studied. Sections were examined by in situ hybridization (ISH) using a cocktail of three synthetic oligonucleotides with sequences chosen from the published sequence of the nucleoprotein gene of respiratory syncytial virus (RS virus). The oligonucleotides were end-labelled with dinitrophenyl (DNP) or digoxigenin (DIG) and hybrids were detected immunocytochemically. RS virus nucleic acid was detected in 24 cases of SIDS (24%) and in 11 (19%) of the comparison group. Specificity was confirmed using a DIG-labeled cloned probe covering the whole of the nucleoprotein gene sequence. With one exception, the same results were obtained. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to confirm the specificity of these results. When matched for age and month and year of death, 76 SIDS cases and 38 controls could be compared. Twenty-one SIDS cases (27.6%) and seven comparison cases (18.4%) contained detectable RS virus sequences by ISH, with a higher detection rate in winter in both groups. The differences were not significant and reflected the seasonal pattern of RS virus infection in the community rather than a causal relationship of RS virus with SIDS. Detection of RS viral mRNA through the summer months suggests that persistence is possible.

Pattern of malformations in the axial skeleton in human triploid fetuses

We examined the axial skeleton in 15 human triploid fetuses (10 with XXX and 5 with XXY sex chromosomes). All fetuses 14-29 weeks of gestational age (GA), underwent whole-body radiography, permitting analysis of the nasal bone and the spine. From 9 of these, detailed radiographs were taken of midsagittal blocks of the cranial base and the spine, permitting detailed analysis of the cranial base.

NASAL BONE

Of 14 fetuses, where the nasal bone was seen on lateral projection, it appeared short in 10 cases.

SPINE

The spine was normal in 7 of 15 fetuses; malformations occurred in 8. These were osseous fusions between 2 or more vertebral bodies, most frequently in the cervical and thoracic regions, and disproportions in the sizes of the cervical bodies. Fusions occurred in 5 cases alone, and in one case in combination with disproportions of vertebral size. Disproportions alone occurred in 2 cases.

CRANIAL BASE

Malformation of the basilar part of the occipital bone was found in 5 of the 9 fetuses investigated. Of 9 fetuses, bilateral ossification centers of the postsphenoid bone occurred in 7, and shell-like ossification centers in 2. There was no difference in the type of malformations in the different axial fields related to genotype (XXX and XXY).

CONCLUSION

The most remarkable findings in the axial skeleton of triploid fetuses are vertebral fusions in 6 of 15 cases; clefts of vertebral bodies, previously reported as common findings in trisomy fetuses, are not demonstrated.

Neurogenic chronic idiopathic intestinal pseudo-obstruction, patent ductus arteriosus, and thrombocytopenia segregating as an X linked recessive disorder

We present a family with three affected males in two generations with congenital neurogenic chronic idiopathic intestinal pseudo-obstruction (CIIP), patent ductus arteriosus, and large platelet thrombocytopenia apparently segregating as an X linked recessive disorder. The pattern of segregation of DNA markers within the family is consistent with linkage to the previously described neurogenic CIIP (CIIPX) locus at Xq28. This combination may represent a new contiguous gene disorder and appears to have a good prognosis with supportive therapy.

A monoclonal antibody pool for routine immunohistochemical detection of human respiratory syncytial virus antigens in formalin-fixed, paraffin-embedded tissue

Four monoclonal antibodies (MAbs) with specificities for epitopes on human respiratory syncytial virus (RSV) proteins preserved after formalin fixation and paraffin embedding were identified in fixed and embedded virus-infected HEp-2 cell pellets. The MAbs bound epitopes on the fusion protein, the nucleoprotein, the phosphoprotein, and the M2 protein of the virus. Following high-temperature antigen unmasking, immunohistochemical staining revealed RSV antigens in the lungs of five of seven children who died with confirmed RSV infection and in none of nine children who died for other reasons, with no evidence of RSV infection. Staining was cytoplasmic, granular, and confined to epithelial cells. Intense staining was seen at the apex of ciliated bronchial and bronchiolar epithelial cells in all five positive cases. In one case, of pneumonitis, infected pneumocytes were present in the alveoli and in several cases, CD68-positive, cytokeratin-negative alveolar macrophages stained for viral antigens. These antibodies may prove useful in studies of the pathogenesis of RSV infection.

Three-year follow-up of bibliotherapy for depression

This study examined the durability of cognitive bibliotherapy for mild to moderately depressed adults by conducting a 3-year follow-up of participants from a previous study (C. Jamison & F. Scogin, 1995). The Hamilton Rating Scale for Depression, Beck Depression Inventory, and questions relating to participants' perceptions of the program were administered. Results indicated that treatment gains were maintained over the 3-year follow-up period and support the usefulness of cognitive bibliotherapy as an adjunct to traditional treatment modalities in a general adult population.

Three-year follow-up of bibliotherapy for depression

This study examined the durability of cognitive bibliotherapy for mild to moderately depressed adults by conducting a 3-year follow-up of participants from a previous study (C. Jamison & F. Scogin, 1995). The Hamilton Rating Scale for Depression, Beck Depression Inventory, and questions relating to participants' perceptions of the program were administered. Results indicated that treatment gains were maintained over the 3-year follow-up period and support the usefulness of cognitive bibliotherapy as an adjunct to traditional treatment modalities in a general adult population.

Mosaic partial trisomy 17 due to a ring chromosome identified by fluorescence in situ hybridisation

We report on a 3-year-old-girl with mosaic partial trisomy 17 due to an additional ring chromosome 17 in 13% of cells analysed. This was identified by fluorescence in situ hybridisation (FISH) using a whole chromosome 17 specific paint as well as probes specific for the Smith-Magenis and Miller-Dieker regions of chromosome 17p. This girl showed mild developmental delay with subtle facial and other minor abnormalities including single palmar creases, generalised joint laxity, and a scoliosis.

A translocation at 12q2 refines the interval containing the Holt-Oram syndrome 1 gene

A gene for Holt-Oram syndrome (HOS) has been previously mapped to chromosome 12q2 and designated HOS1. We have identified a HOS patient with a de novo chromosomal rearrangement involving 12q. Detailed cytogenetic analysis of this case reveals three breaks on 12q, and two of these are within the HOS1 interval. By using a combination of chromosome painting and FISH with YACs and cosmids, it has been possible to map these breakpoints within the critical HOS1 interval and thus provide a focus for HOS gene-identification efforts.

Fetal rhabdomyoma: two instances of recurrence

A congenital fetal rhabdomyoma was removed from the neck of a male infant on the second day of life. The lesion recurred 10 years later with histological features suggestive of increased differentiation and no evidence of malignant transformation. An unrelated patient of 3 years suffered from a recurrent fetal rhabdomyoma 4 months after the initial resection. The possibility of early or late recurrence must be considered when a diagnosis of fetal-type rhabdomyoma is made.

Inversion (14)(q11q32) in a patient with childhood T-cell acute lymphoblastic leukemia

We report a rare example of inversion (14)(q11q32) in childhood T-ALL and its further involvement in a subsequent translocation. We discuss the possible clinical significance of inv(14) in childhood T-ALL.

Ante-natal testicular torsion: only one cause of the testicular regression syndrome?

It has been suggested that the most likely cause of the Testicular Regression Syndrome (TRS) is ante-natal torsion of the testis. As testicular torsion is twice as common on the left this theory cannot explain the incidence of right sided or bilateral cases. From a 5-year retrospective surgical and pathological review, we confirmed that the left testis was the most commonly affected, that boys with TRS tended to be delivered closer to term, and that frequently both testes were present at birth, but one or both subsequently vanished. We also found that direct trauma can produce histological findings indistinguishable from TRS. Close to term, fetal testes are liable to be intrascrotal and therefore susceptible to direct trauma. As the left testis descends into the scrotum at an earlier stage than the right, it is therefore at greater risk of injury. Since the findings of TRS can be produced by direct trauma, we suggest that intra-partum trauma may predispose to the TRS.

Extrarenal Wilms' tumour presenting with intraperitoneal haemorrhage

Extrarenal Wilms' tumours are very rare and have usually been reported as isolated cases. Presentation occurs with a painless abdominal mass. This case report is the first presentation of such a tumour with intraperitoneal haemorrhage. The investigation and surgical management are discussed and the need for urgent surgical assessment reinforced.

Synthetic oligonucleotide cocktails as probes for detection of human parvovirus B19

A cocktail of 10 oligonucleotides selected at intervals along the length of the genome of human parvovirus B19 was labelled enzymically with digoxigenin and chemically with either digoxigenin (DIG) or dinitrophenyl (DNP). Chemical labelling was easier and more practical for the production of large quantities of probe. Pools labelled with either digoxigenin or DNP could detect 10 fg of B19 DNA in a dot blot reaction using an alkaline phosphatase antibody conjugate and colorimetric detection. Formalin fixed tissue from 11 consecutive cases of fetal hydrops were examined by in situ hybridisation (ISH). Both probe cocktails detected human parvovirus B19 DNA in 3 cases, with positive cells in all tissues examined and with equal sensitivity. The DNP pool is significantly cheaper and simpler to produce and could provide an inexpensive reagent suitable for diagnostic detection of viral nucleic acid in histopathological material.

Academic misconduct among nursing students: a multivariate investigation

The purpose of the study was to determine the degree to which several independent variables correlate with perceived instance of academic misconduct among nursing students. Maslow's Need-Goal Motivation Model served as the guiding framework for the study. It was postulated that nursing students' perceptions of their peers' maturity, academic commitment, and neutralizing attitude would be correlated with perceptions of their peers' involvement in various forms of academic misconduct. Results indicated a moderately high degree of correlation exists among the variables (Function I Rc2 = 0.325; p < .001).

A disease resistance gene in Arabidopsis with specificity for two different pathogen avirulence genes

The RPS3 and RPM1 disease resistance loci of Arabidopsis confer resistance to Pseudomonas syringae strains that carry the avirulence genes avrB and avrRpm1, respectively. We have previously shown that RPS3 and RPM1 are closely linked genetically. Here, we show that RPS3 and RPM1 are in fact the same gene. We screened a mutagenized Arabidopsis population with a P. syringae strain carrying avrB and found 12 susceptible mutants. All 12 mutants were also susceptible to an isogenic strain carrying avrRpm1, indicating a loss of both RPS3 and RPM1 functions. No mutants were recovered that lost only RPS3 function. Genetic analysis of four independent mutants revealed that the lesions were in RPS3. Thus, a single gene in Arabidopsis confers resistance that is specific to two distinct pathogen avirulence genes--a gene-for-genes interaction. This observation suggests that the RPS3/RPM1 gene product can bind multiple pathogen ligands, or alternatively, that it does not function as a receptor.

Total anomalous pulmonary venous drainage associated with fatal outcome in infancy and early childhood: an autopsy study of 52 cases

Clinicopathological details of 52 cases of total anomalous pulmonary venous drainage (TAPVD) taken from pediatric autopsy files from hospitals in Adelaide (Australia) Oxford and Edinburgh (United Kingdom) between 1957 and 1990 are presented. The patients ranged in age from a stillborn girl to a 15-month-old boy, with 42 cases (81%) dying in the first 3 months of life. While many patients had signs of a congenital cardiovascular anomaly prior to death, including tachypnea, tachycardia, central cyanosis, cardiac failure, heart murmurs, and difficulty in feeding, it was noteworthy that eight patients (16%) presented as sudden and unexpected death in the absence of significant antemortem symptoms and signs. Anomalous pulmonary venous drainage was also unsuspected prior to death in a total of 26 cases (53%) of those where relevant history was available (49 cases). Twelve infants (23%) underwent surgical correction, none of whom survived more than several weeks. TAPVD was isolated in 30 cases (58%) and was associated with other cardiac or congenital anomalies in 22 patients (42%). Just under half of nonisolated cases comprised the asplenia-heterotaxy syndrome. The points of drainage of the anomalous pulmonary veins were to the infradiaphragmatic veins (n = 21, 40%), left innominate vein (n = 13, 25%), coronary sinus (n = 7, 13%), right superior vena cava (n = 4, 8%), inferior vena cava above the diaphragm (n = 2, 4%), right innominate vein (n = 2, 4%), mixed left innominate vein and coronary sinus (n = 1, 2%), azygos vein (n = 1, 2%), and mixed right superior vena cava and left hemiazygos vein (n = 1, 2%). Twenty-three of 47 cases (49%) that were specifically examined revealed obstruction of the pulmonary veins or pulmonary hypertensive vascular changes on histology. These results emphasize that TAPVD needs to be excluded at autopsy as a causal factor in cases of sudden infant death even in the absence of antemortem symptoms and signs. Clues at autopsy include abnormal mobility of the heart, visceral situs inversus, and polyasplenia. The diversity of pulmonary-systemic venous anastomoses necessitates careful in situ dissection above and below the diaphragm and consideration of postmortem angiography.

Intraduct papillomatosis of the breast in a peripubertal male

A 13-year-old boy presented with right-sided gynecomastia. Histological examination of the excised specimen revealed distention of ducts by papillary configurations of proliferating epithelium. The boy had no known family history of breast disease and physical examination revealed minor dysmorphic features, but a karyotype was normal. The possible relationship of this lesion to other proliferative lesions described in the pubertal male breast is discussed.

Heart block and sudden death associated with fibrosis of the conduction system at the margin of a ventricular septal defect

Isolated ventricular septal defects in clinically well patients are not generally thought to cause sudden death. We document a case in which heart block, with sudden collapse and death, is related to the presence of fibrous interruption of the conduction system of the heart due to progressive fibrous closure of a small ventricular septal defect.

Acyclovir resistant varicella zoster and HIV infection

A child infected with HIV who developed chronic varicella zoster virus infection resistant to acyclovir is presented. The clinical course of the infection, treatment, virological investigations, and relationship of the infection to the child's immunodeficient state are discussed.

Identification of a disease resistance locus in Arabidopsis that is functionally homologous to the RPG1 locus of soybean

A new disease resistance locus in Arabidopsis, RPS3, was identified using a previously cloned avirulence gene from a non-Arabidopsis pathogen. The avrB avirulence gene from the soybean pathogen Pseudomonas syringae pv. glycinea was transferred into a P. syringae pv. tomato strain that is virulent on Arabidopsis, and conversion to avirulence was assayed on Arabidopsis plants. The avrB gene had avirulence activity on most, but not all, Arabidopsis ecotypes. Of 53 ecotypes examined, 45 were resistant to a P. syringae pv. tomato strain carrying avrB, and eight were susceptible. The inheritance of this resistance was examined using crosses between the resistant ecotype Col-0 and the susceptible ecotype Bla-2. In F2 plants from this cross, the ratio of resistant:susceptible plants was approximately 3:1, indicating that resistance to P. syringae expressing avrB is determined by a single dominant locus in ecotype Col-0, which we have designated RPS3. Using RFLP analysis, RPS3 was mapped to chromosome 3, adjacent to markers M583 and G4523, and < or = 1 cM from another disease resistance locus, RPM1. In soybean, resistance to P. syringae strains that carry avrB is controlled by the locus RPG1. Thus, RPG1 and RPS3 both confer avrB-specific disease resistance, suggesting that these genes may be homologs.

Oral teratoma (epignathus) with intracranial extension: a report of two cases

Epignathi are unusual congenital tumours presenting as oropharyngeal masses, often resulting in rapid asphyxia following birth. Occasionally, intracranial extension of the tumour is present, and two such cases are described. The presence of this complication, diagnosable by ultrasound examination, indicates that aggressive surgical treatment is inappropriate.