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Canine demodicosis is a prevalent skin disease caused by overpopulation of a commensal species of Demodex mite, yet its precise cause remains unknown. Research suggests that T-cell exhaustion, increased immunosuppressive cytokines, induction of regulatory T cells and increased expression of immune checkpoint inhibitors may contribute to its pathogenesis. This study aimed to gain a deeper understanding of the molecular changes occurring in canine demodicosis using mass spectrometry and pathway enrichment analysis. The results indicate that endoplasmic reticulum stress promotes canine demodicosis through regulation of three linked signalling pathways: eIF2, mTOR, and eIF4 and p70S6K. These pathways are involved in the modulation of Toll-like receptors, most notably TLR2, and have been shown to play a role in the pathogenesis of skin diseases in both dogs and humans. Moreover, these pathways are also implicated in the promotion of immunosuppressive M2 phenotype macrophages. Immunohistochemical analysis, utilising common markers of dendritic cells and macrophages, verified the presence of M2 macrophages in canine demodicosis. The proteomic analysis also identified immunological disease, organismal injury and abnormalities and inflammatory response as the most significant underlying diseases and disorders associated with canine demodicosis. This study demonstrates that Demodex mites, through ER stress, unfolded protein response and M2 macrophages contribute to an immunosuppressive microenvironment, thereby assisting in their proliferation., (© 2024 The Authors. Parasite Immunology published by John Wiley & Sons Ltd.)

Canine demodicosis is a common skin disease seen in companion animal practice that results from an overpopulation of the commensal Demodex mite species. Common predisposing factors to the development of canine demodicosis include immunosuppressive diseases, such as neoplasia and hypothyroidism, and administration of immunosuppressive therapies, such as corticosteroids. Despite this, the pathogenesis of development of canine demodicosis remains unclear. Previous studies have implicated a role for increased expression of toll like receptor 2 (TLR2), increased production of interleukin (IL)-10) and T cell exhaustion. Here, we investigate gene expression of formalin fixed paraffin embedded skin samples from twelve cases of canine demodicosis in comparison to twelve healthy controls, using a 770 gene panel (NanoString Canine IO Panel). Results show an increase in the T cell population, specifically Th1 and Treg cells in dogs with demodicosis. In addition, while there is an upregulation of immunosuppressive cytokines such as IL-10 and IL-13, there is also an upregulation of immune check point molecules including PD-1/PD-L1 and CTLA-4. These findings suggest that Demodex spp. mites are modulating the host immune system to their advantage through upregulation of several immune tolerance promoting pathways., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Objectives: To explore clinicopathological features of peripheral odontogenic fibromas in dogs and risk factors for their diagnosis., Materials and Methods: Data of cases with a histopathological diagnosis of peripheral odontogenic fibromas were obtained from a UK-based diagnostic laboratory and retrospectively reviewed. Prevalence amongst all biopsy submissions was assessed using binomial tests and Clopper-Pearson intervals. Age at diagnosis was assessed using t-test for independent samples. Lesion location, sex, and neuter status were assessed using χ 2 and post hoc binomial tests. Breed odds ratios were calculated using univariable logistic regression modelling., Results: The prevalence of peripheral odontogenic fibromas amongst all biopsy submissions was 2.8% (1001 of 35,328, 95% confidence interval [CI]: 2.7 to 3.0). The mean (sd) age was 8.1 (±2.7) years. The most affected quadrant was the rostral maxilla (40.1%). The ratio of maxillary to mandibular lesions was 1.3:1 (95% CI: 1.1 to 1.5), and for cases of multiple peripheral odontogenic fibromas the ratio of maxillary to mandibular lesions was 2.4:1 (95% CI: 1.1 to 5.6). Males had 1.2 times the odds of suffering of peripheral odontogenic fibromas compared to females (odds ratio [OR]: 1.2, 95% CI: 1.1 to 1.4). Neutering was associated with an increased risk of diagnosis (OR: 1.6, 95% CI: 1.3 to 1.9). Breeds with increased odds of peripheral odontogenic fibromas compared to crossbreed dogs included boxers (OR: 3.78, 95% CI: 2.80 to 5.09), border terriers (OR: 3.21, 95% CI: 2.10 to 4.91) and Basset Hounds (OR: 3.18, 95% CI: 1.58 to 6.44). Breeds with increased odds of multiple simultaneous peripheral odontogenic fibromas compared to crossbreed dogs included: Boxers (OR: 12.02, 95% CI: 7.13 to 20.24), border terriers (OR: 5.05, 95% CI: 2.32 to 11.43) and Staffordshire Bull terriers (OR: 2.42, 95% CI: 1.33 to 4.41)., Clinical Significance: Knowledge of clinicopathological features and at-risk breeds for peripheral odontogenic fibroma development can assist clinicians with making a diagnosis. The identification of risk factors provides targets for future research investigating peripheral odontogenic fibroma pathogenesis., (© 2023 British Small Animal Veterinary Association.)

Clinical diagnostic reports from 508 cases of canine demodicosis diagnosed either by histological or skin scraping analysis from a United Kingdom Accreditation Service (UKAS) accredited veterinary diagnostic laboratory servicing the United Kingdom (UK) and Ireland were evaluated. Of the 508 cases, 284 had skin swabs submitted for culture on the same day the skin biopsy and/or skin scraping were obtained. Dogs with juvenile-onset (JO) demodicosis represented 57.4% of these cases, whilst adult-onset (AO) cases comprised 42.6%. The data revealed that overgrowth of pathogenic bacteria was more common in AO demodicosis cases (75.2%) in comparison to the JO cases (57%). Adult-onset cases also had increased involvement of bacteria belonging to multiple genera and/or yeast (28.9%) in comparison to JO cases (18.4%). Pruritus was significantly associated with an overgrowth of Staphylococcus pseudintermedius (p < 0.001). Resistance to one or more antimicrobial classes was noted in S. pseudintermedius isolates from 56.3% of JO cases with 10.3% of these cases being classified as Multi-Drug Resistant (MDR). Similarly, 51.9% of S. pseudintermedius isolates from the AO cases were noted to be resistant to one or more antimicrobial class with 8.6% of these cases being considered MDR. Cephalosporins were the most frequently administered antimicrobial class noted in submission histories, followed by the penicillin and fluoroquinolone classes. Whilst our findings reveal a high prevalence of concurrent overgrowth of pathogenic bacteria warranting therapeutic intervention in canine demodicosis, the presence of resistance within isolates highlights the need for prudent selection and targeted use of antimicrobial therapy that encompass the key principles of antimicrobial stewardship., Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Canine demodicosis, due to an overpopulation of Demodex spp. mites, remains one of the most common dermatological diseases encountered in small animal practice. The aims of this study were to interrogate submitted histories and diagnostic report results from a large cohort of dogs (n = 508) diagnosed with demodicosis either through histological analysis or the finding of Demodex spp. mites on skin scrapings by a UKAS accredited commercial laboratory servicing the United Kingdom (UK) and Ireland in the years 2017 and 2018. The main findings revealed that short-coated breeds were more likely to develop juvenile-onset (JO) demodicosis, whereas medium- and long-coated breeds were more likely to develop adult-onset (AO) disease. Pododemodicosis was reported more commonly in adult, long-coated breeds. Skin scrapings were positive in only 83.3% of samples that had a corresponding positive biopsy result; this finding highlights the necessity to perform further diagnostic tests if demodicosis remains clinically suspected despite a negative skin scraping result. Concurrent underlying diseases, potentially associated with immunosuppression, were reported in 42/221 (19%) of dogs with AO demodicosis. Serum allergy and Sarcoptes ELISA assays were positive in individual animals in both the JO and AO groups; the clinical significance of these latter findings requires careful interpretation in dogs with confirmed demodicosis., Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A significant proportion of canine urothelial carcinomas carry the driver valine to glutamic acid variation (V595E) in BRAF kinase. The detection of V595E may prove suitable to guide molecularly targeted therapies and support non-invasive diagnosis of the urogenital system by means of a liquid biopsy approach using urine. Three cohorts and a control group were included in this multi-step validation study which included setting up a digital PCR assay. This was followed by investigation of preanalytical factors and two alternative PCR techniques on a liquid biopsy protocol. Finally, a blind study using urine as diagnostic sample has been carried out to verify its suitability as diagnostic test to complement cytology. The digital PCR (dPCR) assay proved consistently specific, sensitive, and linear. Using the dPCR assay, the prevalence of V595E in 22 urothelial carcinomas was 90.9%. When compared with histopathology as gold standard in the blind-label cases, the diagnostic accuracy of using the canine BRAF (cBRAF) variation as a surrogate assay against the histologic diagnosis was 85.7% with 92.3% positive predictive value and 80.0% negative predictive value. In all the cases, in which both biopsy tissue and the associated urine were assayed, the findings matched completely. Finally, when combined with urine sediment cytology examination in blind-label cases with clinical suspicion of malignancy, the dPCR assay significantly improved the overall diagnostic accuracy. A liquid biopsy approach on urine using the digital PCR may be a valuable breakthrough in the diagnostic of urothelial carcinomas in dogs., Competing Interests: CP, MN, JM, and FS are employed by IDEXX Laboratories Ltd. TF is employed by Private Veterinary Clinic San Marco Srl. MT is employed by Genefast srl. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Gentilini, Palgrave, Neta, Tornago, Furlanello, McKay, Sacchini and Turba.)

Cancer is a major reason for veterinary consultation, especially in companion animals. Cancer surveillance plays a key role in prevention but opportunities for such surveillance in companion animals are limited by the lack of suitable veterinary population health infrastructures. In this paper we describe a pathology-based animal tumour registry (PTR) developed within the Small Animal Veterinary Surveillance Network (SAVSNET) built from electronic pathology records (EPR) submitted to this network. From an original collection of 180232 free text (non-structured) EPRs reported between April 2018 and June 2019, we used specific text-mining methodologies to identify 109895 neoplasias. These data were normalized to describe both the tumour (type and location) and the animal (breed, neutering status and veterinary practice postcode). The resulting PTR, the largest of its kind for companion animals to date, is an important research resource being able to facilitate a wide array of research in areas including surveillance, clinical decision making and comparative cancer biology., (© 2021. The Author(s).)

Target capture sequencing effectively generates molecular marker arrays useful for molecular systematics. These extensive data sets are advantageous where previous studies using a few loci have failed to resolve relationships confidently. Moreover, target capture is well-suited to fragmented source DNA, allowing data collection from species that lack fresh tissues. Herein we use target capture to generate data for a phylogeny of the avian family Pipridae (manakins), a group that has been the subject of many behavioral and ecological studies. Most manakin species feature lek mating systems, where males exhibit complex behavioral displays including mechanical and vocal sounds, coordinated movements of multiple males, and high speed movements. We analyzed thousands of ultraconserved element (UCE) loci along with a smaller number of coding exons and their flanking regions from all but one species of Pipridae. We examined three different methods of phylogenetic estimation (concatenation and two multispecies coalescent methods). Phylogenetic inferences using UCE data yielded strongly supported estimates of phylogeny regardless of analytical method. Exon probes had limited capability to capture sequence data and resulted in phylogeny estimates with reduced support and modest topological differences relative to the UCE trees, although these conflicts had limited support. Two genera were paraphyletic among all analyses and data sets, with Antilophia nested within Chiroxiphia and Tyranneutes nested within Neopelma. The Chiroxiphia-Antilophia clade was an exception to the generally high support we observed; the topology of this clade differed among analyses, even those based on UCE data. To further explore relationships within this group, we employed two filtering strategies to remove low-information loci. Those analyses resulted in distinct topologies, suggesting that the relationships we identified within Chiroxiphia-Antilophia should be interpreted with caution. Despite the existence of a few continuing uncertainties, our analyses resulted in a robust phylogenetic hypothesis of the family Pipridae that provides a comparative framework for future ecomorphological and behavioral studies., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The tropics are the source of most biodiversity yet inadequate sampling obscures answers to fundamental questions about how this diversity evolves. We leveraged samples assembled over decades of fieldwork to study diversification of the largest tropical bird radiation, the suboscine passerines. Our phylogeny, estimated using data from 2389 genomic regions in 1940 individuals of 1283 species, reveals that peak suboscine species diversity in the Neotropics is not associated with high recent speciation rates but rather with the gradual accumulation of species over time. Paradoxically, the highest speciation rates are in lineages from regions with low species diversity, which are generally cold, dry, unstable environments. Our results reveal a model in which species are forming faster in environmental extremes but have accumulated in moderate environments to form tropical biodiversity hotspots., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Objective and Design: TNF-α neutralization is associated with increased mortality in mouse cecal ligation puncture (CLP) models. AZD9773 is an ovine polyclonal human TNF-α immune Fab, with pharmacological properties that differ from previously studied anti-TNF-α agents. We explored the safety and efficacy of therapeutically administered AZD9773 in mouse CLP sepsis., Methods: A moderate/severe-grade CLP model resulting in 20-30 % 5-day survival and a mild-grade CLP model resulting in ~70 % 5-day survival were established in human TNF-α transgene/murine TNF null (Tg1278/-/-) mice., Treatment: Mice received saline resuscitation and imipenem administration every 12 h (0-72 h post-CLP). AZD9773 (or DigiFab control) was dosed 24, 36, 48 and 60 h post-CLP., Results: Therapeutic dosing of AZD9773 in moderate/severe-grade CLP resulted in significantly increased survival (>70 %) compared with DigiFab (27 %, P < 0.05). Therapeutic dosing of AZD9773 in mild-grade CLP did not significantly affect survival outcome compared with DigiFab or imipenem alone (~60-70 % survival)., Conclusions: These data demonstrate that TNF-α neutralization can improve survival in moderate/severe CLP sepsis. TNF-α suppression in mild-grade models was not associated with survival benefit and did not increase 5-day mortality. These findings suggest that therapeutic benefit following TNF-α attenuation in models of sepsis may depend on model severity.

The 2010 annual National Toxicology Program (NTP) Satellite Symposium, entitled "Pathology Potpourri," was held in Chicago, Illinois, in advance of the scientific symposium sponsored jointly by the Society of Toxicologic Pathology (STP) and the International Federation of Societies of Toxicologic Pathologists (IFSTP). The goal of the annual NTP Symposium is to present current diagnostic pathology or nomenclature issues to the toxicologic pathology community. This article presents summaries of the speakers' presentations, including diagnostic or nomenclature issues that were presented, along with select images that were used for voting or discussion. Some topics covered during the symposium included a comparison of rat and mouse hepatocholangiocarcinoma, a comparison of cholangiofibrosis and cholangiocarcinoma in rats, a mixed pancreatic neoplasm with acinar and islet cell components, an unusual preputial gland tumor, renal hyaline glomerulopathy in rats and mice, eosinophilic substance in the nasal septum of mice, INHAND nomenclature for proliferative and nonproliferative lesions of the CNS/PNS, retinal gliosis in a rat, fibroadnexal hamartoma in rats, intramural plaque in a mouse, a treatment-related chloracne-like lesion in mice, and an overview of mouse ovarian tumors.

Introduction: We have evaluated the ability of a semi-automated, optomotor reflex method to assess drug-induced visual dysfunction, in albino and pigmented rats and mice., Methods: Male Han Wistar (HW) and Long Evans (LE) rats and mice (CD-1 and C57BL/6) were tested in a chamber formed by 4 computer monitors displaying a rotating vertical grating, to elicit head-tracking movements. The highest visible grating frequency was taken as the threshold of visual acuity, in cycles per degree (c/d). Animals received an intravenous infusion of either sodium iodate (50mg/kg) or 0.9% w/v NaCl (aq). They were tested 2h later, then re-tested daily for a further 3 days. The time course of the effect was assessed in HW rats over a 6-week period, including electron microscopy, and immunohistochemical analysis of markers of injury and repair in the retina., Results: Baseline visual acuities for HW and LE rats were 0.355 ± 0.007 and 0.530 ± 0.004 c/d, respectively, and 0.296 ± 0.003 c/d and 0.370 ± 0.001 c/d for CD-1 and C57BL/6 mice, respectively (n=10 for each). In HW rats there was a dramatic loss of visual acuity 2h after administration of sodium iodate (0.021 ± 0.021 c/d; P<0.001). Less dramatic decreases in visual acuity were seen in LE rats and in the two mouse strains. In HW rats, visual acuity was restored after 4 weeks. This paralleled the histopathological recovery of the peripheral retina, whereas the central retina did not recover., Discussion: The method proved to be very convenient, and the stability of visual acuity in vehicle control rats over a 6-week period also demonstrated its suitability for inclusion in long-term toxicity studies. Both albino and pigmented mice and rats are suitable for assessment of retinotoxicity using this method, but albino rats are the most sensitive to sodium iodate., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Pathology peer review verifies and improves the accuracy and quality of pathology diagnoses and interpretations. Pathology peer review is recommended when important risk assessment or business decisions are based on nonclinical studies. For pathology peer review conducted before study completion, the peer-review pathologist reviews sufficient slides and pathology data to assist the study pathologist in refining pathology diagnoses and interpretations. Materials to be reviewed are selected by the peer-review pathologist. Consultations with additional experts or a formal (documented) pathology working group may be used to resolve discrepancies. The study pathologist is solely responsible for the content of the final pathology data and report, makes changes resulting from peer-review discussions, initiates the audit trail for microscopic observations after all changes resulting from peer-review have been made, and signs the final pathologist's report. The peer-review pathologist creates a signed peer-review memo describing the peer-review process and confirming that the study pathologist's report accurately and appropriately reflects the pathology data. The study pathologist also may sign a statement of consensus. It is not necessary to archive working notes created during the peer-review process.

We have previously shown that kainic acid (KA) increases nitric oxide (NO) synthase (NOS) production in the rat dentate gyrus (DG) and hippocampus (CA3), and NOS inhibition [(by N(G)-nitro-L-arginine methylester (L-NAME)] modulates the vasoactive intestinal peptide (VIP)-responsive gene, activity-dependent neuroprotective protein, and alters neuro- and astrogliogenesis (Cosgrave et al. in Neurobiol Dis 30(3):281-292 2008, J Mol Neurosci 39(1-2):9-21, 2009, 2010). In the present study, using the same model we demonstrate that VIP synthesis is differentially regulated by the NO-cyclic guanosine monophosphate (cGMP) pathway in the DG and CA3 at 3 h and 3 days post-KA. At 3 h post-KA: In L-NAME+KA/7-nitroindazole (7-NI)+KA, stratum granulosum (SG) and subgranular zone (SGZ) cells were intensely stained for VIP when compared with L-NAME/7-NI/KA alone. Soluble guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, blocks cGMP production), suppressed astrocytic activation (glial fibrillary acidic protein) but other cell types were VIP(+); however, ODQ+KA suppressed overall VIP synthesis in the DG. At 3 days post-KA: In L-NAME+KA/7-NI+KA, SGZ and SG cells continued to express VIP, while in the KA alone, only SGZ cells were VIP(+). ODQ increased VIP(+) cells in the SG, and in contrast to 3 h, VIP-containing nNOS(+) cells increased in ODQ+KA when compared to vehicle+KA. In the hippocampus, 7-NI/ODQ had no effect on VIP at 3 h/3 days, while L-NAME+KA at 3 days increased VIP(+) cells, but reduced VIP-like immunoreactivity in astrocytes. These results suggest that the NO-cGMP pathway differentially regulates VIP in the DG and hippocampus during seizure.

Treatment with the nitric oxide synthase (NOS) inhibitor, L-NAME prior to the induction of seizures with kainic acid (KA) [L-NAME+KA] increases the expression of activity-dependent neuroprotective protein (ADNP) in cells in the subgranular zone (SGZ) of the rat dentate gyrus 3-days after seizure induction (Cosgrave et al., 2009). Using the incorporation of BrdU we found that this protocol [L-NAME+KA] stimulates neuro- and gliogenesis. By comparison, L-NAME or KA alone produced smaller effects. Doublecortin+ (BrdU negative) neuroblasts in the SGZ also significantly increased with L-NAME+KA treatment, suggesting that L-NAME+KA cause more cells to differentiate into neurons. L-NAME alone increased BrdU+ astrocytes in the hilus implying that NO inhibits stem cell differentiation into astrocytes and may also influence their migration. Although NOS inhibition increased cell proliferation in vivo and in vitro it disrupted cell clustering as revealed by ADNP immunoreactivity. In vitro KA treatment resulted in eccentric nuclei, reduced neurite extension and branching in neurons and retracted processes of glia cells, these changes were inhibited with prior treatment of L-NAME suggesting that KA-induced NO production affects cell morphology. Consequently, this data suggests an important role for NO in regulating stem cell proliferation and their fate in the SGZ.

The dentate gyrus (DG) of the normal rat brain contains activity-dependent neuroprotective protein (ADNP) which is widely distributed in the cytoplasm of neurons and astrocytes. Treatment with nitric oxide (NO) synthase (NOS) inhibitor N(G)-nitro-L: -arginine methyl ester (L: -NAME) caused a decrease in ADNP expression in granule cells which persisted 3 days post-treatment. However, treatment with neuronal-specific NOS inhibitor, 7-nitroindazole (7-NI), or soluble guanylyl cyclase inhibitor, ODQ, did not change ADNP expression in the DG. We have previously shown that kainic acid (KA)-induced seizure increases neuronal NOS in neurons and inducible NOS in glia cells and suppresses ADNP in the hippocampus (Cosgrave et al., Neurobiol Dis 30(3):281-292, 2008). In the DG, L: -NAME treatment prior to KA causes ADNP synthesis in granule cells by 3 h which was later restricted to the subgranular zone by 3 days. 7-NI and ODQ had no effect. Double immunostaining for neuronal marker NeuN and ADNP revealed a significant decrease of both ADNP(+) neurons and of total neuron numbers (NeuN(+)) in the hilus of animals having KA-induced seizure that had been pretreated with L: -NAME implying that NO and ADNP may act together to protect hilar neurons. Overall, these observations suggest that NO regulates ADNP in the DG under both basal and pathophysiological conditions.

Unlike most other tissues, the optimal fixative for preserving eye morphology is considered to be Davidson's fixative or modified Davidson's rather than formalin. However, the methodology for antibodies to be used in tissues fixed this way is not normally outlined in current antibody datasheets. Additionally, where eyes have been stored in Davidson's fixative, the efficacy of retrospective analysis of eye morphology by immunohistochemistry is largely unknown. The aim of this study was to compare a panel of six antibodies in both Davidson's-fixed and formalin-fixed pigmented and non-pigmented rat eyes, in order to provide optimal methods for future retinal immunohistochemical evaluation with image analysis. The antibodies evaluated were raised against rhodopsin, synaptophysin, glutamine synthetase, glial fibrillary acidic protein (GFAP), cleaved caspase-3 and phospho-histone H3 (PH3). Overall, the staining quality of these antibodies was found to be optimal in Davidson's compared to formalin-fixed tissues after a time period of up to 4 days in fixative. The methods outlined thus provide a platform for future detailed analysis of retinal pathology in Davidson's-fixed eyes.

Activity-dependent neuroprotective protein (ADNP) is widely distributed in the cytoplasm of neurons and astrocytes of the hippocampus. Kainic acid (KA)-induced seizures increases neuronal nitric oxide synthase (nNOS) in neurons and inducible NOS (iNOS) in glia cells which coincides with a reduction in ADNP in the hippocampus. Inhibitors of NOS or soluble guanylyl cyclase (sGC) activity reduce ADNP under basal conditions in the absence of seizures. Treating animals with these inhibitors prior to KA-induced seizure, in particular, L-NAME (N(G)-nitro-l-arginine methyl ester), advances the onset of the first seizure but reverses the loss of ADNP by 3 days after the first seizure. This suggests that the NO-cGMP pathway has a role in regulating ADNP under both basal physiological conditions and in the pathophysiological changes produced during epileptogenesis.

Constitutive activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signaling pathway in human cancers is often associated with mutational activation of BRAF or RAS. MAPK/ERK kinase 1/2 kinases lie downstream of RAS and BRAF and are the only acknowledged activators of ERK1/2, making them attractive targets for therapeutic intervention. AZD6244 (ARRY-142886) is a potent, selective, and ATP-uncompetitive inhibitor of MAPK/ERK kinase 1/2. In vitro cell viability inhibition screening of a tumor cell line panel found that lines harboring BRAF or RAS mutations were more likely to be sensitive to AZD6244. The in vivo mechanisms by which AZD6244 inhibits tumor growth were investigated. Chronic dosing with 25 mg/kg AZD6244 bd resulted in suppression of growth of Colo-205, Calu-6, and SW-620 xenografts, whereas an acute dose resulted in significant inhibition of ERK1/2 phosphorylation. Increased cleaved caspase-3, a marker of apoptosis, was detected in Colo-205 and Calu-6 but not in SW-620 tumors where a significant decrease in cell proliferation was detected. Chronic dosing of AZD6244 induced a morphologic change in SW-620 tumors to a more differentiated phenotype. The potential of AZD6244 in combination with cytotoxic drugs was evaluated in mice bearing SW-620 xenografts. Treatment with tolerated doses of AZD6244 and either irinotecan or docetaxel resulted in significantly enhanced antitumor efficacy relative to that of either agent alone. These results indicate that AZD6244 has potential to inhibit proliferation and induce apoptosis and differentiation, but the response varies between different xenografts. Moreover, enhanced antitumor efficacy can be obtained by combining AZD6244 with the cytotoxic drugs irinotecan or docetaxel.

Leukaemia inhibitory factor (LIF) and nerve growth factor (NGF) are well characterized regulators of galanin expression. However, LIF knockout mice containing the rat galanin 5' proximal promoter fragment (- 2546 to + 15 bp) driving luciferase responded to axotomy in the same way as control mice. Also, LIF had no effect on reporter gene expression in vitro, neither in the presence or absence of NGF, suggesting that other factors mediate an axotomy response from the galanin promoter. We then addressed the role of nitric oxide (NO) using NGF-deprived rat dorsal root ganglion (DRG) neuron cultures infected with viral vectors containing the above-mentioned construct, and also studied endogenous galanin expression in axotomized DRG in vivo. Blocking endogenous NO in NGF-deprived DRG cultures suppressed galanin promoter activity. Consistent with this, axotomized/NGF-deprived DRG neurons expressed high levels of neuronal NO synthase (nNOS) and galanin. Further, using pharmacological NOS blockers, or adenoviral vectors expressing dominant-negative either for nNOS or soluble guanylate cyclase in vivo and in vitro, we show that the NO-cGMP pathway induces endogenous galanin in DRG neurons. We propose that both LIF and NO, acting at different promoter regions, are important for the up-regulation of galanin, and for DRG neuron survival and regeneration after axotomy.

Nerve growth factor (NGF)-deprivation or axotomy of dorsal root ganglion (DRG) neurons causes stress, which they cope by triggering various mechanisms. Among several molecular changes, in the present study, we demonstrate preprotachykinin-A-substance P (PPTA-SP) and activity-dependent neuroprotective protein-vasoactive intestinal peptide (ADNP-VIP) expression pattern using DRG neurons-Schwann cells coculture and axotomy model. In the presence of NGF, DRG cultures showed high levels of PPTA and ADNP mRNA expression, which were significantly suppressed in the absence of NGF and/or nitric oxide synthase (NOS) inhibition by NG-nitro-L-arginine methyl ester (L-NAME), suggesting that both NGF and nitric oxide (NO) can regulate PPTA and ADNP expression. However, treating coculture with NO donor, diethylenetriamine nitric oxide (DETA-NO) did not increase PPTA and ADNP expression in the presence or absence of NGF, although there was a marginal increase in ADNP expression in the absence of NGF. NGF-deprivation increases endogenous NO; thus, DETA-NO had no further effect on PPTA and ADNP expression. Alternatively, NGF produced from NO-stimulated Schwann cells influence gene expression. In addition, interestingly, DETA-NO treatment of Schwann cells alone suppresses both PPTA and ADNP, suggesting differential response of DRG neurons-Schwann cells coculture to DETA-NO. SP and ADNP immunostaining of axotomized DRGs revealed significant reduction in SP and ADNP compared to intact DRG, which was partially recovered in neuronal NOS blocker, 7-nitroindazole (7-NI)-treated DRGs, particularly intense ADNP staining in satellite glia. As ADNP is VIP-responsive gene, we further explored VIP expression in DRGs. Axotomy increased VIP in DRG neurons, but 7-NI treatment caused intense VIP staining in satellite glia. These observations suggest a complex interaction of NO-NGF with PPTA/SP and ADNP-VIP in neuron-glial communication when neurons are stressed.

Nitric oxide (NO) is a biological messenger molecule produced by one of the essential amino acids L-arginine by the catalytic action of the enzyme NO synthase (NOS). The dual role of NO as a protective or toxic molecule is due to several factors, such as; the isoform of NOS involved, concentration of NO and the type of cells in which it is synthesised, the availability of the substrate L-arginine, generation of guanosine 3,5'-cyclic monophosphate (cGMP) from soluble guanylate cyclase and the overall extra and intracellular environment in which NO is produced. NOS activation as a result of trauma (calcium influx) or infection leads to NO production, which activates its downstream receptor sGC to synthesise cGMP and/or leads to protein nitrosylation. This may lead to one or more systemic effects including altered neurotransmission which can be protective or toxic, vaso/bronchodilatation in the cardiovascular and respiratory systems and enhanced immune activity against invading pathogens. In addition to these major functions, NO plays important role in thermoregulation, renal function, gastrointestinal motility, endocrine function, and various functions of the urogenital system ranging from renin secretion to micturation; spermatogenesis to penile erection; and ovulation to implantation and parturition. A schematic summary of the functions of NO and the various isoforms of NOS expressed in body systems is shown in figure 1. In this review, the historical background, biochemistry and biosynthesis of NO and its enzymes together with the mechanism of NO actions in physiology and pathophysiology are discussed.

The use of tissue microarrays (TMAs) in the determination of novel target molecule distribution in organs is an expanding area of discovery pathology. This pilot study was carried out to assess the Chromavision automated cellular imaging system (ACIS) for quantitation of both mRNA and protein distribution in rat and dog TMAs. The targets chosen were a protein kinase, P-CIP2, for mRNA assessment and its downsteam target, peptidylglycine amidating monoxygenase (PAM), for immunohistochemistry (IHC). Oligonucleotide probes produced against P-CIP2, together with an antibody against PAM, were evaluated on rat and dog TMAs. A method for evaluation of target distribution using the ACIS was developed and involved a two-tier approach. Firstly, an initial scanning of the labelled slides identified which tissues expressed the target. Secondly, a more comprehensive analysis was made. This required operator interaction to select specific regions of interest within selected tissue cores and exclude any background labelling from the final assessment. This exacted the level of expression of P-CIP2 or PAM in different cellular populations in tissue cores. A comparative semi-quantitative analysis of the same arrays was concomitantly made by the pathologist in order to assess the relative benefits of a potentially time-consuming detailed morphological evaluation. This involved the histological identification by the pathologist of specific cell populations expressing P-CIP2 or PAM. In this study, we demonstrate the power of an image analysing system to provide quantitative data on target distribution by in situ hybridisation and IHC on normal TMAs. This methodology, together with detailed histological analysis by a pathologist, forms a guideline for future target distribution evaluation within discovery pathology.

The role of nitric oxide (NO) in various systems of the body has gained prominence since the last decade. The dual role of NO either as a toxic or protective molecule depends on the concentrations of NO being produced, the isoform of NO synthase involved and the type of cell in which NO produced. The protective roles of NO appear to be mediated via cross talk between neurotrophic pathways. In view of this, in this paper, the role of NO in the enteric system is discussed with respect to neuronal nitric oxide synthase expression in neurons associated with the gut and the nerve growth factor and its receptor, tyrosine kinase A expression in the lamina epithelialis.

During early embryonic (E12) development almost all dorsal root ganglion (DRG) neurons express the neuronal isoform of nitric oxide synthase (nNOS). At this stage, the axons of these neurons are rudimentary and have not made contact with peripheral tissue targets. As their axons establish contact with peripheral targets such as the skin, the number of neurons expressing nNOS decrease that correspond to increased immunoreactivity for nerve growth factor (NGF) in the skin, and its high affinity receptor, tyrosine kinase A (trkA) in both skin and DRG neurons. During late postnatal development, very few DRG neurons express nNOS; however, axotomy or NGF deprivation of cultured DRG neurons induce nNOS and NOS blockade causes neuronal death. In contrast, NGF-deprived embryonic and neonatal DRG neurons die by apoptosis, while NOS blockade has no effect. Overall, these observations suggest that NGF and nitric oxide (NO) interact during embryonic and postnatal development to facilitate neuronal selection and survival. The roles of NO, NGF and its receptor trkA in DRG neurons during different stages of development are discussed.

The NO-cGMP pathway has emerged as a neuroprotective signaling system involved in communication between neurons and glia. We have previously shown that axotomy or nerve growth factor (NGF)-deprivation of dorsal root ganglion (DRG) neurons leads to increased production of NO and at the same time an increase in cGMP production in their satellite glia cells. Blockade of NO or its receptor, the cGMP synthesizing enzyme soluble guanylate cyclase (sGC), results in apoptosis of neurons and glia. We now show that co-culture of neonatal DRG neurons with either Schwann cells pre-treated with an NO donor or a membrane-permeant cGMP analogue; or neurons maintained in the medium from Schwann cell cultures treated in the same way, prevents neuronal apoptosis. Both NO donor and cGMP treatment of Schwann cells results in synthesis of NGF and NT3. Furthermore, if the Schwann cells are previously infected with adenoviral vectors expressing a dominant negative sGC mutant transgene, treatment of these Schwann cells with an NO donor now fails to prevent neuronal apoptosis. Schwann cells treated in this way also fail to express neither cGMP nor neurotrophins. These findings suggest NO-sGC-cGMP-mediated NGF and NT3 synthesis by Schwann cells protect neurons.

Histone acetyltransferases and histone deacetylases are protein-modifying enzymes involved in addition and removal of acetyl groups on histone proteins, respectively. These molecules play a pivotal role in cellular functions such as chromosome remodelling, gene transcription and cell proliferation. Histone deacetylase inhibitors (HDIs) have been shown to cause cell cycle arrest, cellular differentiation and inhibition of cell proliferation in tumor cells in vitro and in vivo. Their potential use for cancer therapy is currently under evaluation in clinical trials. A pilot study was performed to immunohistochemically evaluate the effects of a HDI, "Compound 1", on acetylation, proliferation, mitosis, and apoptosis in tumor xenografts (Calu-6, SW 620, Colo 205, and LoVo) in nude mice, at 6, 24, and 48 hours, following a single oral dose. Qualitative immunohistochemistry and computer-assisted image analysis demonstrated an increase in acetylation in all xenografts. Immunohistochemical analysis of acetylation in skin showed increased acetylation at 6 hours after HDI administration. In addition, image analysis showed a decrease in mitosis and an increase in metaphase mitotic figures in the SW 620 xenograft. These two findings were consistent with a G1/S cell cycle phase arrest. Increased apoptosis of SW 620 and LoVo xenografts was also observed following treatment.

The parasite Neospora caninum is an important cause of abortion in cattle world-wide. Chronically infected dams transmit the parasite transplacentally and infected foetuses may be aborted or born chronically infected but clinically normal. Chronically infected cows repeatedly transmit the parasite to foetuses in several pregnancies and some may abort more than once suggesting that the immune response in these cattle is compromised during pregnancy. To investigate the nature of the immune response in chronically infected cattle, five naturally, chronically infected cows were challenged with N. caninum tachyzoites at 10 weeks of gestation. No foetopathy occurred and all five delivered live calves at full-term. In four naive pregnant cows challenged at the same time, all four foetuses died within 3-5 weeks of challenge. Of the five live calves born to the chronically infected challenged cows, three were transplacentally infected with N. caninum. The kinetics of the maternal anti-N. caninum antibody responses during gestation suggested that these transplacental infections were not the result of the superimposed challenge, but the result of the recrudescence of the maternal chronic infection-which occurred concurrently in non-challenged, chronically infected pregnant controls. These data provide the first experimental evidence that protective immunity occurs in neosporosis. They also suggest that whilst immunity to a pre-existing infection will protect against an exogenous challenge, this protective immunity will not prevent transplacental infection. This implies that a subtle form of concomitant immunity exists in chronically infected cattle and has important implications for vaccine development.

After being anaesthetised for between one hour 40 minutes and seven hours, five adult horses developed acute neurological signs and extensive cerebrocortical necrosis. Four of them had had abdominal surgery for colic and one had had repeated orthopaedic interventions. Between five hours and seven days after the surgery, all five horses suddenly developed severe signs of a predominantly prosencephalic disturbance: bilateral blindness with normal pupillary light responses, abnormal behaviour varying from propulsive pacing to head pressing profound lethargy and generalised seizures. They were euthanased between 24 hours and three weeks after the onset of these signs. In three of the cases a gross examination of the brain revealed patchy malacia of the cerebral grey matter and some discolouration of the adjacent white matter. Microscopical examination revealed lesions that varied from laminar neuronal necrosis in the grey matter of the cerebral cortex to more diffuse necrosis of the cortex and underlying white matter. Four of the five cases had had a period of hypercapnea while anaesthetised, and two of them (and possibly a third) had also had hypoxaemia.

This paper addresses the issues of tracing and compliance encountered in setting up and maintaining a UK-wide 5-year observational study of beef cattle. The 5-year prospective study was initiated in 1997 to investigate the occurrence of bovine spongiform encephalopathy (BSE) in a single herd of pedigree Aberdeen Angus cattle, in which BSE had been detected at low prevalence. The study was given the acronym ULiSES (University of Liverpool Spongiform Encephalopathy Scheme). All cattle present on the farm at the start of the scheme were registered as members of the study population (n=320), as were all calves subsequently born on the farm (n=350). Animals that were sold (n=291) were traced and monitored at destination farms. Farmers were requested to give advance notification of slaughter of any ULiSES animal and an attempt was made to collect post-mortem samples of nervous tissue, peripheral lymphoid tissue and striated muscle from all animals in the scheme at the time of slaughter, death or euthanasia. Sections of medulla were examined (by standard histopathological techniques) for the presence of spongiform change. Remaining samples were stored at -70 degrees C for future investigation by alternative tests. At the halfway point of the scheme in October 1999, 75.2% (506/673) of the study population was still alive; 42% (284) of the population was still alive on the study farm and 33% (222) was distributed on other farms throughout the UK. Complete sets of specimens had been recovered from 77% (129/167) of dead animals. All brainstem sections were negative by histopathological examination. No suspect cases of BSE were reported in ULiSES animals. Failure to recover specimens occurred principally in animals which had left the study farm. The main cause of specimen loss was a failure of compliance in a small number of individuals who had purchased large numbers of ULiSES animals, and subsequently slaughtered them without contacting the University. Despite this, farmer compliance was generally high. The ULiSES scheme shows the feasibility of a country-wide longitudinal observational study spanning a period of several years and indicates the large impact of small numbers of non-compliant individuals.

Axotomised dorsal root ganglia (DRG) neurons show an increased expression of neuronal nitric oxide synthase (nNOS) compared with neurons from the intact ganglia. Increased nNOS expression resulted in synthesis of nitric oxide (NO) and the subsequent activation of cGMP in satellite glia cells surrounding the DRG neuron soma. In dissociated DRG we have demonstrated that the increase in nNOS expression is regulated by nerve growth factor and that the subsequent inhibition of NO production or cGMP synthesis precipitates apoptosis of neurons expressing nNOS and some non-nNOS neurons. Hence, NO or the NO-cGMP cascade appears to have a neuroprotective action in trophic factor-deprived DRG neurons. In the present study, using immunocytochemistry, we have investigated some of the factors associated with apoptosis that are activated when nNOS activity is blocked with NOS inhibitor in DRG neurons in vitro. Marked elevation of bax was observed within a few hours of NOS inhibition in nNOS containing neurons, whereas pretreatment of cultures with l-arginine completely abolished this effect in almost all nNOS neurons and 8-bromo-cGMP in some neurons. The apoptosis precipitated by NOS inhibition was also partially prevented by a number of caspase inhibitors; of those a caspase-9 blocker was the most effective. These observations further support the neuroprotective role of NO/NO-cGMP in stressed DRG neurons in an autocrine fashion that involves the suppression of bax, caspase-3 and -9 activation.

A 10-year-old male domestic shorthaired cat had a chronic, slowly enlarging subcutaneous mass on the right side of its nose. At the time of presentation, the nasal airflow was severely impeded on the affected side. The cat had been treated medically with various drugs. Oral itraconazole had been the most effective in reducing the size of the mass, but had caused hepatotoxicity and had to be withdrawn. The mass was finally removed surgically, and a diagnosis of granulomatous cellulitis caused by Alternaria alternata (phaeohyphomycosis) was established, based on histopathology and fungal isolation. There has been no recurrence of the lesion after 21 months and the cat remains clinically well at the time of writing. Subcutaneous phaeohyphomycosis caused by A alternata has not, to the authors' knowledge, been previously described in small domestic animals in the UK.

The clinical and hematologic features of two cases of probable essential thrombocythemia in the dog are described. Both dogs presented with hepatosplenomegaly, severe nonregenerative anemia, neutrophilia and Thrombocytosis. Mean platelet volume and percentages of large platelets were markedly increased in both dogs. Platelet aggregation studies demonstrated hyperaggregability in one dog; platelets from the other dog aggregated spontaneously, precluding further investigation. Cytologic and histologic examination of bone marrow showed pronounced megakaryocytic hyperplasia, with erythroid hypoplasia and relative myeloid hyperplasia. Megakaryocyte morphology was abnormal, with increased numbers of small mononuclear and binucleate cells. Normal to increased hemosiderin stores suggested that apparent macrocytosis in one dog, rather than being due to iron deficiency, resulted from the hematology analyzer counting large platelets as small red blood cells. Megakaryocytic infiltration of the spleen was evident in both dogs. The hematologic findings in dogs with essential thrombocythemia can mimic those associated with iron deficiency anemia, such that diagnostic investigations should be aimed at ruling out chronic blood loss and other causes of reactive Thrombocytosis.

A tumour occupying the fourth ventricle in a 3-year-old cat was removed surgically and characterized as a tanycytic ependymoma on the basis of histological features of low cellularity, inconspicuous perivascular pseudorosettes and fascicular architecture. Immunohistochemical analysis of sections revealed that the neoplastic cells were immunoreactive for glial fibrillary acidic protein (GFAP), vimentin and S-100. The histological and immunohistochemical findings were similar to those of human tanycytic ependymoma, a subclassification of ependymoma not previously described in domestic species.

In a previous study, we described the inhibitory effects of the growth factor-antagonist, trapidil, on spontaneously occurring oligodendrocyte remyelination in the rat spinal cord following lysolecithin-induced demyelination [30]. The objective of the present study was to further investigate the mechanisms of trapidil-mediated impairment of remyelination and thus obtain greater insight into the steps at which growth factors may be involved in remyelination. To this end, an ultrastructural analysis of the cellular composition of lesions from control and trapidil-treated animals was undertaken. Demyelination was created in the dorsal funiculus of 6-week-old female rats by the injection of 1.0 microliter of 1% lysolecithin. The animals received daily intraperitoneal injections of trapidil (80 mg/kg) or saline for 21 days, beginning on the day of lesion induction. Quantitative electron microscopic examination of lesions from both groups of animals showed that trapidil-treated lesions had reduced numbers of oligodendrocytes (P = 0.02) with a higher relative proportion of immature phenotypes, but increased numbers of microglia (P = 0.0009) and dystrophic axons (P0.02). In addition, the numbers of myelin lamellae around remyelinated axons were fewer in trapidil-treated animals. These results suggest that trapidil-mediated impairment of CNS remyelination is due to a blockage of growth factor-mediated proliferation and/or recruitment of remyelinating cells. Furthermore, the presence of oligodendrocytes with a more immature phenotype and the decreased thickness of the myelin sheaths of remyelination in the trapidil-treated animals indicate an impairment of growth factor-mediated differentiation.

In this study we describe the effects of trapidil, a putative platelet-derived growth factor-antagonist, on spontaneously occurring remyelination in rat spinal cord. Demyelination was created in the dorsal funiculus of 6- and 11-week-old female rats by the direct injection of 1.0 microliter of 1% lysolecithin. The animals received daily intra-peritoneal injections of either trapidil or saline for 21 days, commencing on the day of lesion induction. The 11-week-old rats receiving trapidil (60 mg/kg) showed a significant decrease in the extent of oligodendrocyte remyelination. Moreover, those axons that were remyelinated by oligodendrocytes tended to have thinner myelin sheaths than axons remyelinated by oligodendrocytes in the control group. In the 6-week-old group, the dose of trapidil which inhibited oligodendrocyte remyelination in the 11-week-old animals had a minimal effect on the extent of oligodendrocyte remyelination and no effect on the quality of myelin sheath formation. A higher dose of trapidil (80 mg/kg) was required before significant impairment of oligodendrocyte remyelination was achieved in the younger age group, implying an age-dependent effect of growth factor-inhibition of CNS remyelination. These results indicate an important role for growth factors, and in particular PDGF, in the orchestration of oligodendrocyte remyelination in the rodent CNS.

We have examined the effects of the mitogenic growth factors platelet derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and glial growth factor-2 (GGF-2) on oligodendrocyte precursor migration. In an agarose drop migration assay PDGF and bFGF stimulated migration while GGF-2 had no effect. The migration-enhancing effect of bFGF cannot be blocked by neutralising antibodies against PDGF, confirming that this effect is direct and not mediated via upregulation of PDGF receptors. Based on our results, we propose a model in which the differing effects of PDGF and GGF-2 ensure appropriate numbers of oligodendrocyte precursor cells in the vicinity of axons to be myelinated during development.

Malignant histiocytosis is a rare disease which is characterised by the neoplastic proliferation of tissue macrophages (histiocytes) leading to excessive phagocytosis of erythrocytes. The clinical signs and pathological findings in three Bernese mountain dogs are described. Two of the dogs had the same sire. The disease has been established as a familial problem in Bernese mountain dogs in other countries, although it has not been previously recorded in the United Kingdom.

A patient is described with oesophageal ulceration due to herpes simplex virus type I. The endoscopic, light, electron microscopic, and immunohistochemical appearances are described and the literature of this under-diagnosed entity is reviewed.

We studied the influence of morphine on intestinal secretion induced by three different secretogogues in an attempt to elucidate the mechanism for its antisecretory activity. In rabbit ileal mucosa in vitro morphine (10(-4) M) did not influence the electrical response to the subsequent administration of prostaglandin E2 or of acetylcholine but did inhibit the net secretion of chloride provoked by both agents and prevented the reduction of sodium adsorption induced by the prostaglandin. Morphine reduced the peak electrical response to cholera toxin and reduced toxin-induced net chloride secretion. The modes of action of morphine appeared to be by both enhancing adsorption, as it does in control, nonsecreting mucosa, and by inhibiting secretogogue activity.

Histamine is present in high concentrations in the intestine and we investigated the possibility that it might have a role here in intestinal transport. When added to the basal side of rabbit ileal mucosa in vitro histamine (10(-4)M) induced a short-lived increase in electrical potential difference and short circuit current. It inhibited net chloride absorption but did not influence sodium transport. Alkali secretion, measured by a pH stat technique, was inhibited, suggesting that bicarbonate secretion was reduced. Both the electrical and ion flux responses to histamine were blocked by the H1 receptor blocker diphenhydramine, but not by the H2 receptor blocker cimetidine. The presence of specific H1 histamine receptors was further supported by shifts in the dose-response curve to histamine by four different concentrations of diphenhydramine. Calculation of a pA2 value from these "Schild' plots provided a figure of 7.85, which is similar to that for H1 receptors in other tissues. Aminoguanidine, a histaminase blocker, had no electrical effects alone but shifted the histamine dose response curve to the left. These studies indicate that histamine inhibits chloride absorption and alkali secretion, possibly by influencing a chloride/bicarbonate exchange process, through specific mucosal H1 receptors. Enhancement of histamine effects by a histaminase inhibitor suggests that histaminases are present in the intestinal mucosa and supports the possibility of a role for endogenous histamine in influencing ion transport. The observations indicate a mechanism by which absorption might be impaired in diseases in which histamine is liberated locally in the intestine.

To investigate the pathogenesis of diarrhea in inflammatory bowel disease, electrolyte transport was examined in vitro in stripped colonic mucosa taken from the sigmoid or descending colon in colectomy specimens. Compared with previously reported values from normal colon, the electrical potential difference, short circuit current, and mucosal resistance were significantly lower in diseased mucosa. This reduction was associated with a significantly lower net sodium absorption in diseased mucosa, owing to a reduced mucosa to serosa unidirectional flux. Net chloride flux was similar to normal, but unidirectional fluxes were reduced. In mucosa from patients treated with corticosteroids, fluxes were similar to normal, while in untreated patients they were markedly impaired. It is concluded that there is a defect in active sodium absorption in inflammatory bowel disease that may contribute to the diarrhea. A secretory process, inhibited by sulphasalazine, cannot be excluded however.

Forty-eight patients successfully completed a six-week, double blind, placebo controlled trial of ranitidine hydrochloride 200mg twice daily for active duodenal ulceration. Following endoscopy 68% of the patients taking ranitidine had healed, compared to 35% of those who were taking placebo. Nineteen of the patients who had not healed then took a further six weeks of open active treatment; of these, 14 were successfully treated. Thirty-one of the patients who had healed duodenal ulcers then took ranitidine hydrochloride 100mg at night as a maintenance treatment for one year: 71% remained endoscopically and symptomatically in remission. No serious side effects were encountered.

Opiates are commonly used as antidiarrheal agents, and endogenous opioids have been demonstrated in the intestine. It seemed important therefore to investigate the effects of morphine on ion transport across intestinal mucosa. In rabbit ileum in vitro morphine (2 x 10(-5) M) induced a significant fall in potential difference and short circuit current but did not influence tissue resistance. Dextromoramide (10(-5) M), an active opiate, mimicked the action of morphine, whereas the inactive isomer levomoramide (10(-5) M) had no effect. Morphine caused a significant increase in chloride absorption, due predominantly to a decrease in the serosa to mucosa flux. No change in sodium transport was detected, but the residual ion flux, possibly representing bicarbonate secretion, was enhanced. Similar response were observed with a synthetic enkephalin analogue (Me-Tyr-D-Met-Gly-Phe-Pro-NH2); but this was more potent than morphine, a significant electrical response being observed at a concentration as low as 10(-8) M. These electrical and ion transport responses to morphine were blocked by naloxone, an effect shown to be competitive in nature. The results suggest that opiate receptors exist in rabbit ileal mucosa and that these influence electrical and ion transport changes across the mucosa.