The chromosomes of the nine-banded armadillo,Dasypus novemcinctus

Summary The chromosomes of the nine-banded armadillo, Dasypus novemcinctus, were studied using cultured peripheral leukocytes, tissue cells and direct preparation of male germ cells.The diploid number was found to be 64 in the blood and tissue cells, the haploid number was 32 in the testicular preparations.The autosomes can be divided into six groups, according to their size and the position of the centromere. Group A contains two pairs of large metacentrics, Groups B and C contain together 18 pairs of acrocentric chromosomes, the distinguishing feature being a gradual decrease in size. Group D is composed of six pairs of small metacentric chromosomes with almost medial centromeres. One prominentld satellited chromosome constitutes a ready marker element of this groud and of the karyotype. It is not entirely certain whether this satellitey chromosome has a homologue or not. Five pairs of small acrocentrics constitute Group E. These are almost indistinguishable from one another.Buccal smears showed a typical sex chromatin body in interphase nuclei of epithelial cells from female animals similar to that observed in some other mammals. A sex difference was also noted on examination of peripheral blood films, typical drumsticks being present on polymorphonuclear leukocytes from female armadillos.     

LL5beta is a phosphatidylinositol (3,4,5)-trisphosphate sensor that can bind the cytoskeletal adaptor,gamma-filamin

We identified a potential phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P(3)) binding pleckstrin homology domain in the data bases and have cloned and expressed its full coding sequence (LL5beta). The protein bound PtdIns(3,4,5)P(3) selectively in vitro. Strikingly, a substantial proportion of LL5beta became associated with an unidentified intracellular vesicle population in the context of low PtdIns(3,4,5)P(3) levels produced by the addition of wortmannin or LY294002. In addition, expression of platelet-derived growth factor-receptor mutants unable to activate type 1A phosphoinositide 3-kinase (PI3K) or serum starvation in porcine aortic endothelial cells lead to redistribution of LL5beta to this vesicle population. Importantly, pleckstrin homology domain mutants of LL5beta that could not bind PtdIns(3,4,5)P(3) were constitutively localized to this vesicle population. At increased PtdIns(3,4,5)P(3) levels, LL5beta was redirected to a predominantly cytoplasmic distribution, presumably through a PI3K-dependent block on its targeting to the vesicular compartment. Furthermore, at high, hormone-stimulated PtdIns(3,4,5)P(3) levels, it became significantly plasma-membrane localized. The distribution of LL5beta is thus dramatically and uniquely sensitive to low levels of PtdIns(3,4,5)P(3) indicating it can act as a sensor of both low and hormone-stimulated levels of PtdIns(3,4,5)P(3). In addition, LL5beta bound to the cytoskeletal adaptor, gamma-filamin, tightly and in a PI3K-independent fashion, both in vitro and in vivo. This interaction could co-localize heterologously expressed gamma-filamin with GFP-LL5beta in the unidentified vesicles.     

Proliferation Index: A Continuous Model to Predict Prognosis in Patients with Tumours of the Ewing's Sarcoma Family

The prognostic value of proliferation index (PI) and apoptotic index (AI), caspase-8, -9 and -10 expression have been investigated in primary Ewing''s sarcoma family of tumours (ESFT). Proliferating cells, detected by immunohistochemistry for Ki-67, were identified in 91% (91/100) of tumours with a median PI of 14 (range 0–87). Apoptotic cells, identified using the TUNEL assay, were detected in 96% (76/79) of ESFT; the median AI was 3 (range 0–33). Caspase-8 protein expression was negative (0) in 14% (11/79), low (1) in 33% (26/79), medium (2) in 38% (30/79) and high (3) in 15% (12/79) of tumours, caspase-9 expression was low (1) in 66% (39/59) and high (3) in 34% (20/59), and caspase-10 protein was low (1) in 37% (23/62) and negative (0) in 63% (39/62) of primary ESFT. There was no apparent relationship between caspase-8, -9 and -10 expression, PI and AI.PI was predictive of relapse-free survival (RFS; p = 0.011) and overall survival (OS; p = <0.001) in a continuous model, whereas AI did not predict outcome. Patients with tumours expressing low levels of caspase-9 protein had a trend towards a worse RFS than patients with tumours expressing higher levels of caspase-9 protein (p = 0.054, log rank test), although expression of caspases-8, -9 and/or -10 did not significantly predict RFS or OS. In a multivariate analysis model that included tumour site, tumour volume, the presence of metastatic disease at diagnosis, PI and AI, PI independently predicts OS (p = 0.003). Consistent with previous publications, patients with pelvic tumours had a significantly worse OS than patients with tumours at other sites (p = 0.028); patients with a pelvic tumour and a PI≥20 had a 6 fold-increased risk of death. These studies advocate the evaluation of PI in a risk model of outcome for patients with ESFT.     

Antidiabetic Sulphonylureas Stimulate Acetylcholine Release from Striatal Cholinergic Interneurones Through Inhibition of KATP Channel Activity

Abstract: The sulphonylureas tolbutamide and glibenclamide were shown to stimulate acetylcholine release from rat striatal slices. To determine the mechanism of this effect, whole-cell patch-clamp recordings were made from large neurones within the striatum that displayed morphological, electrophysiological, and pharmacological characteristics typical of cholinergic interneurones. Dialysis of these neurones with a pipette solution containing low concentrations of ATP produced a gradual hyperpolarisation that could be reversed by bath application of the sulphonylureas. In voltage-clamp studies, these compounds were shown to act through the inhibition of a potassium conductance. It is concluded that cholinergic interneurones within the rat striatum express sulphonylurea-sensitive ATP-sensitive potassium channel activity. These channels are probably cytoprotective and may prove to be novel sites of therapeutic modulation.     

Fatty acids in the milk of goats after cessation of lactation

Regular hand milking of six goats was discontinued after 32-35 weeks of lactation. A few days after milking out ceased, the concentration of triglyceride in peripheral blood plasma increased. Over a period of weeks, the concentration of triglyceride in small samples of fluid taken from the teat canal fell gradually. Lipase activity of the milk fluid was temporarily reduced shortly after milking out ended, but, despite this, its concentration of free fatty acids increased. It is suggested that free fatty acids are released during clearance of milk triglyceride from residual fluid in the mammary gland after cessation of lactation.     

Cyst formation and faecal–oral transmission of Dientamoeba fragilis – the missing link in the life cycle of an emerging pathogen

Dientamoeba fragilis is a protozoan parasite emerging as a cause of diarrhoea and “irritable-bowel-like” gastrointestinal disease in humans with a propensity for establishing long-term, chronic infections in humans. Although Dientamoeba was discovered over a century ago its life cycle and mode of transmission is not known. No cyst stage has been described and no animal models are presently available for the study of this parasite. Here we describe the establishment of an animal model using laboratory rodents, the fulfilling of Koch’s postulates, and the discovery of a new cyst stage in the life cycle of D. fragilis. Our demonstration of long-term parasite carriage by rodents and prolonged shedding of cysts, together with elevated levels of calprotectin in the stool, confirms the capacity of this organism to cause disease and indicates dientamoebiasis should be considered in the differential diagnosis of gastrointestinal diseases such as Inflammatory Bowel Syndrome (IBS). Finally, we suggest that the cyst stage described here is the vehicle that mediates faecal–oral transmission of D. fragilis between hosts.