Exploring the hemicellulolytic properties and safety of Bacillus paralicheniformis as stepping stone in the use of new fibrolytic beneficial microbes

Bacillus strains from the Moroccan Coordinated Collections of Microorganisms (CCMM) were characterised and tested for fibrolytic function and safety properties that would be beneficial for maintaining intestinal homeostasis, and recommend beneficial microbes in the field of health promotion research. Forty strains were investigated for their fibrolytic activities towards complex purified polysaccharides and natural fibres representative of dietary fibres (DFs) entering the colon for digestion. We demonstrated hemicellulolytic activities for nine strains of Bacillus aerius, re-identified as Bacillus paralicheniformis and Bacillus licheniformis, using xylan, xyloglucan or lichenan as purified polysaccharides, and orange, apple and carrot natural fibres, with strain- and substrate-dependent production of glycoside hydrolases (GHs). Our combined methods, based on enzymatic assays, secretome, and genome analyses, highlighted the hemicellulolytic activities of B. paralicheniformis and the secretion of specific glycoside hydrolases, in particular xylanases, compared to B. licheniformis. Genomic features of these strains revealed a complete set of GH genes dedicated to the degradation of various polysaccharides from DFs, including cellulose, hemicellulose and pectin, which may confer on the strains the ability to digest a variety of DFs. Preliminary experiments on the safety and immunomodulatory properties of B. paralicheniformis fibrolytic strains were evaluated in light of applications as beneficial microbes' candidates for health improvement. B. paralicheniformis CCMM B969 was therefore proposed as a new fibrolytic beneficial microbe candidate.

POS0468 EXTRACELLULAR VESICLES FROM SERUM OF MYOSITIS PATIENTS AS CIRCULATING BIOMARKERS AND DISEASE MEDIATORS

Background

Inflammatory myopathies (IM) are a heterogeneous group of disorders characterized by autoimmune inflammatory destruction of skeletal muscles. It is many times associated with lung, skin and joint involvement. Identifying biomarkers that can differentiate IM from other muscle disorders may elucidate the pathophysiology of IM, guide novel therapies, monitor disease activity/response to treatments and predict prognosis. Exosomes are membrane-bound nanovesicles with diameters of 30-150 nm that contain multiple proteins, nucleic acid, lipids and other molecules in a tissue- and cell-specific manner. Exosomes are secreted by a large variety of cells, play major roles in cell-cell interactions, and have recently emerged as circulating biomarkers in a variety of pathological conditions, including several autoimmune diseases.

Objectives

To characterize exosomes from serum of IM patients, analyze protein expression and study their potential mediators of disease pathologies.

Methods

Serum was collected from patients suffering from IM(n=5) and from patients suffering from Becker (BMD) and Duchenne (DMD) muscular dystrophies (n=6). Exosomes were isolated by Exoquick precipitation and analyzed for size distribution and by nanoparticle tracking analysis (NTA) and by Western blot for exosome markers. The effects of the isolated EVs on human satellite cell proliferation and differentiation and macrophage activation were examined.

Results

Exosomes from IM patients decreased human satellite cell proliferation (51%, P<0.01) and inhibited their myogenic differentiation as indicated by lower fusion index (24% inhibition, P<0.01) and expression of myosin heavy chain (72% inhibition, P<0.001). Similar results were obtained also with exosomes derived from DMD and BMD patients; however, their inhibitory effect were more pronounced on MyoG expression. Treatment of macrophages with exosomes from IM patients significantly increased the expression of IL-10 (3-fold, P<0.001), compared to exosomes of healthy controls and DMD patients. Another significant difference was in the expression of signaling molecules: Thus, exosomes from BMD patients increased the phosphorylation of Erk and p38, whereas a smaller effect was induced by IM exosomes.

Conclusion

Exosomes from IM patients decrease satellite cell proliferation and myogenic differentiation compared to healthy exosomes. In addition, these exosomes increased the expression of IL-10 in macrophages. These effects are unique to exosomes of IM patients compared to muscular dystrophies. These promising results suggest that serum exosomes should be further investigated as a novel biomarker with potential therapeutic implications.

Disclosure of Interests

Shaye Kivity Speakers bureau: BI, Abbvie, Lilly, Pfizer, Janssen, Neopharm, Grant/research support from: Sobi, Haya Kravitz: None declared, Coral Cohen: None declared, Darya Margoulis: None declared, Moshe Amar: None declared, Gila Kazimirsky: None declared, David Ozeri Speakers bureau: Neopharm, Consultant of: Abbvie, Amir Dori Grant/research support from: Biogen, Chaya Brodie Grant/research support from: Biogen.

Captopril Versus Hydralazine-Isosorbide Dinitrate Vasodilator Protocols in Patients With Acute Decompensated Heart Failure Transitioning From Sodium Nitroprusside

BACKGROUND

The role of oral vasodilators in the management of acute decompensated heart failure (ADHF) is not clearly defined. We evaluated the use of captopril vs hydralazine-isosorbide dinitrate (H-ISDN) in the transition from sodium nitroprusside (SNP) in patients with ADHF.

METHODS AND RESULTS

A retrospective chart review was performed of 369 consecutive adult patients in the intensive care unit with ADHF and reduced ejection fraction, who received either a captopril or an H-ISDN protocol to transition from SNP. Captopril patients were matched 1:2 to H-ISDN patients, based on serum creatinine and race (Black vs non-Black). Baseline demographics, serum chemistry and use of angiotensin converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) were similar in both groups. Time to SNP discontinuation (46.9 vs 40.4 hours, P = 0.11) and length of hospital stay (9.86 vs 7.99 days, P = 0.064) were similar in both groups. Length of hospital stay in the intensive care unit was statistically shorter in the H-ISDN group (4.11 vs 3.96 days, P = 0.038). Fewer H-ISDN protocol patients were discharged on ACEis/ARBs (82.9 % vs 69.9%, P = 0.003) despite similar kidney function at time of discharge (serum creatinine 1.1 vs 1.2, P = 0.113). No difference was observed in rates of readmission (40.7% vs 50%, P = 0.09) or mortality (16.3% vs 17.5 %, P = 0.77) at 1 year postdischarge.

CONCLUSION

Similar inpatient and 1-year outcomes were observed between patients using H-ISDN vs ACEi when transitioning from SNP, even though fewer H-ISDN protocol patients were discharged taking ACEis/ARBs despite similar kidney function.

The bacterial diversity of raw Moroccon camel milk

Dromedary camel milk is generally considered a valuable and marketable commodity but its production suffers from poor hygienic conditions that result in low microbiological quality and the presence of various pathogens. The objective of the present study was to provide a detailed report of the bacterial species level composition of Moroccan raw camel milk samples that can serve as a starting point for the selection of starter cultures to facilitate a change in manufacturing practices to an improved and safer production system. The composition of the bacterial community in four freshly collected raw camel milk samples was analyzed by performing a large-scale isolation campaign combined with 16S rRNA gene amplicon sequencing. A total of 806 isolates were obtained from four raw camel milk samples using ten combinations of growth media and incubation conditions. Subsequent isolate dereplication using MALDI-TOF mass spectrometry and identification of representative isolates through sequence analysis of protein encoding and 16S rRNA genes revealed the presence of established and novel dairy lactic acid bacteria, as well as bacteria that are considered indicators of poor hygienic conditions and psychrotrophic spoilage organisms. The large numbers of Lactococcus and Enterococcus isolates obtained present an interesting resource for starter culture selection.

RNA-seq reveals mechanisms of SlMX1 for enhanced carotenoids and terpenoids accumulation along with stress resistance in tomato

Improving nutritional fruit quality and impacts important agro-traits such as biotic or abiotic stresses are extremely important for human civilization. Our previous study reported that manipulation of SlMX1 gene enhanced carotenoids accumulation and drought resistance in tomato. Here, RNA-Seq analysis proved to be a very useful tool to provide insights into the regulatory mechanisms of SlMX1 involved in stress resistance and enhanced secondary metabolites. Physiological analysis showed that over-expression of SlMX1 results in substantially increased broad-spectrum tolerance to a wide-range of abiotic and biotic (fungus, bacteria, virus and insects) stresses in tomato. This research appears to be of remarkable interest because enhanced terpenoids content has been achieved by increasing trichome density. In addition, we reported two types of trichome which seems to be aberrant types in tomato. This study unravels the mechanism of regulation of SlMX1, which simultaneously modulates resistance and metabolic processes through regulating key structural and regulatory genes of the corresponding pathways.

Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. subtilis (subsp. spizizenii (2) and subsp. inaquosurum (6)), B. amyloliquefaciens (subsp. amyloliquefaciens (4) and subsp. plantarum (4)), B. tequilensis (3), B. pumilus (3) and Bacillus sp. (19). Only six isolates (2.5%) belonged to the genus Aeribacillus represented by A. pallidus (4) and Aeribacillus sp. (2). In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

Streptococcus moroccensis sp. nov. and Streptococcus rifensis sp. nov., isolated from raw camel milk

Two catalase- and oxidase-negative Streptococcus -like strains, LMG 27682T and LMG 27684T, were isolated from raw camel milk in Morocco. Comparative 16S rRNA gene sequencing assigned these bacteria to the genus Streptococcus with Streptococcus rupicaprae 2777-2-07T as their closest phylogenetic neighbour (95.9 % and 95.7 % similarity, respectively). 16S rRNA gene sequence similarity between the two strains was 96.7 %. Although strains LMG 27682T and LMG 27684T shared a DNA–DNA hybridization value that corresponded to the threshold level for species delineation (68 %), the two strains could be distinguished by multiple biochemical tests, sequence analysis of the phenylalanyl-tRNA synthase (pheS), RNA polymerase (rpoA) and ATP synthase (atpA) genes and by their MALDI-TOF MS profiles. On the basis of these considerable phenotypic and genotypic differences, we propose to classify both strains as novel species of the genus Streptococcus , for which the names Streptococcus moroccensis sp. nov. (type strain, LMG 27682T = CCMM B831T) and Streptococcus rifensis sp. nov. (type strain, LMG 27684T = CCMM B833T) are proposed.

[Prescription of methylphenidate for children: importance of recommendations to limit misuse]

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder appearing during childhood. Multimodal strategies have been developed to treat this disorder, some of them including medication. To this day in France, prescriptions are mainly based on methylphenidate. Ever since this drug was marketed in France in 1995, it has been subject to enhanced monitoring, mainly because of the risk of dependence, abuse, and misuse. The present study aims at assessing (1) whether the recommendations on methylphenidate use for children are being respected, (2) the extent of problematic use of methylphenidate, and (3) the impact of said recommendations being respected on the development of problematic consumption. We studied patients who were treated with methylphenidate in an academic child psychiatry department. We specifically developed a semistructured interview grid for this study. Both parents and children were interviewed. In almost three out of four cases, at least one recommendation had not been followed (52% of patients did not follow the recommendation of stopping use during weekends and holidays). We found an average of 1.6 (range, 0-5) recommendations that were not respected. In almost two out of three cases, the consumption of methylphenidate was problematic; for 40% of children, this meant the search for at least one effect other than the expected therapeutic effects, such as an intellectual, creative, or athletic boosting effect. Approximately one-third of parents also sought an effect other than therapeutic for their child. Conversely, if all of the prescription recommendations were followed, less problematic consumption was observed. Methylphenidate-based treatments must therefore be implemented after a specialist has evaluated the patient and be prescribed following the recommendations. In this context, the treatment's benefits are undeniable.

Helix stabilization of amphipathic peptides by hydrocarbon stapling increases cholesterol efflux by the ABCA1 transporter

Apolipoprotein mimetic peptides are short amphipathic peptides that efflux cholesterol from cells by the ABCA1 transporter and are being investigated as therapeutic agents for cardiovascular disease. We examined the role of helix stabilization of these peptides in cholesterol efflux. A 23-amino acid long peptide (Ac-VLEDSFKVSFLSALEEYTKKLNTQ-NH2) based on the last helix of apoA-I (A10) was synthesized, as well as two variants, S1A10 and S2A10, in which the third and fourth and third and fifth turn of each peptide, respectively, were covalently joined by hydrocarbon staples. By CD spectroscopy, the stapled variants at 24 °C were more helical in aqueous buffer than A10 (A10 17%, S1A10 62%, S2A10 97%). S1A10 and S2A10 unlike A10 were resistant to proteolysis by pepsin and chymotrypsin. S1A10 and S2A10 showed more than a 10-fold increase in cholesterol efflux by the ABCA1 transporter compared to A10. In summary, hydrocarbon stapling of amphipathic peptides increases their helicity, makes them resistant to proteolysis and enhances their ability to promote cholesterol efflux by the ABCA1 transporter, indicating that this peptide modification may be useful in the development of apolipoprotein mimetic peptides.

Impaired GABAergic transmission disrupts normal homeostatic plasticity in rat cortical networks

In the cortex, homeostatic plasticity appears to be a key process for maintaining neuronal network activity in a functional range. This phenomenon depends on close interactions between excitatory and inhibitory circuits. We previously showed that application of a high frequency of stimulation (HFS) protocol in layer 2/3 induces parallel potentiation of excitatory and inhibitory inputs on layer 5 pyramidal neurons, leading to an unchanged excitation/inhibition (E/I) balance. These coordinated long-term potentiations of excitation and inhibition correspond to homeostatic plasticity of the neuronal networks. We showed here, on the rat visual cortex, that blockade (with gabazine) or overactivation (with 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) of GABA(A) receptors enhanced the E/I balance and prevented the potentiation of excitatory and inhibitory inputs after an HFS protocol. These impairements of the GABAergic transmission led to a long-term depression-like effect after an HFS protocol. We also observed that the blockade of inhibition reduced excitation (by 60%), and conversely, the blockade of excitation decreased inhibition (by 90%). These results support the idea that inhibitory interneurons are critical for recurrent interactions underlying homeostatic plasticity in cortical networks.

Detection of venous invasion in surgical specimens of colorectal carcinoma: the efficacy of various types of tissue blocks

BACKGROUND

Venous invasion (VI) is an important prognosis predictor after colorectal carcinoma (CRC) resection, enabling more accurate staging and influencing postoperative management.

AIMS

To assess/compare various tissue block types (perpendicular, tangential, across mesentery (AM), from major vessels or lymph nodes (LNs)) for VI detection in CRC.

METHODS

Fifty two CRCs (51 colectomies, one polypectomy) were studied. Tumours were measured, surface area calculated, and colorectum and bowel wall sites recorded. Weigert's staining for elastin facilitated VI detection. VI sites, type, and amount were recorded. Ratios of relative yield of tissue block types to their frequency were calculated.

RESULTS

Average numbers of tissue blocks/colectomy specimen were: perpendicular, 10.2; tangential, 9.1; AM, 3.3; from major vessels, 2.1. Average number of LNs examined was 16.47. VI was detected in 22 tumours. Overall, VI was detected in 16 perpendicular, seven tangential, five AM, and two LN blocks. VI was detected in eight, two, one, and three tumours in perpendicular, tangential, LN, and AM blocks alone, respectively. In seven tumours, VI was identified in multiple tissue block types. The average number of blocks obtained was 39.7, 42.1, and 38 from all tumours, VI positive, and VI negative tumours, respectively (p = 0.0497). Efficacy to detect VI was 2.151, 2.088, 1.092, 0.172, and 0 for AM, perpendicular, tangential, LN, and mesenteric vessel blocks, respectively.

CONCLUSIONS

VI was identified most frequently and in eight cases only in perpendicular blocks. However, extramural VI was detected in six tumours only in blocks cut tangentially, AM, or from harvested LNs. Hence, all these types of blocks should be submitted routinely and scanned for VI.

Biodiversity of lactic acid bacteria in Moroccan soft white cheese (Jben)

The bacterial diversity occurring in traditional Moroccan soft white cheese, produced in eight different regions in Morocco, was studied. A total of 164 lactic acid bacteria were isolated, purified and identified by whole-cell protein fingerprinting and rep-PCR genomic fingerprinting. The majority of the strains belonged to the genera Lactobacillus, Lactococcus, Leuconostoc and Enterococcus. Sixteen species were identified: Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus paracasei, Lactobacillus brevis, Lactobacillus buchneri, Lactococcus lactis, Lactococcus garvieae, Lactococcus raffinolactis, Leuconostoc pseudomesenteroides, Leuconostoc mesenteroides, Leuconostoc citreum, Eterococcus durans, Enterococcus faecalis, Enterococcus faecium, Enterococcus saccharominimus and Streptococcus sp.

Enterococcus saccharominimus sp. nov., from dairy products

Four isolates, which were obtained from Belgian, Moroccan and Romanian dairy products, constituted a homogeneous but unidentified taxon after screening with whole-cell protein fingerprinting. Complete 16S rRNA gene sequence analysis classified representative strains in the genus Enterococcus. Highest sequence similarities of 98.6 and 98.0 % were obtained with the species Enterococcus sulfureus and Enterococcus saccharolyticus, respectively. Growth characteristics, biochemical features, tRNA intergenic length polymorphism analysis, DNA-DNA hybridization and DNA G+C contents of selected strains demonstrated that they represent a single, novel Enterococcus species. It differs phenotypically from other enterococci in characteristics commonly considered as typical of this genus: no growth in 6.5 % NaCl or 0.4 % sodium azide, and no acid production from a wide range of carbohydrates. The name Enterococcus saccharominimus sp. nov. is proposed for this novel species; the type strain (LMG 21727(T)=CCM 7220(T)) was isolated from contaminated pasteurized cow's milk.

Chryseomonas luteola identified as the source of serious infections in a Moroccan University Hospital

Chryseomonas luteola has only rarely been reported as a human bacterial pathogen. It has been shown that this organism in particular affects patients with health or indwelling disorders. Most reported cases showed septicemia, meningitis, endocarditis, or peritonitis. Two C. luteola infections observed in Morocco are described in the present study.

Cholinergic modulation of the cortical neuronal network

Acetylcholine (ACh) is an important neurotransmitter of the CNS that binds both nicotinic and muscarinic receptors to exert its action. However, the mechanisms underlying the effects of cholinergic receptors have still not been completely elucidated. Central cholinergic neurons, mainly located in basal forebrain, send their projections to different structures including the cortex. The cortical innervation is diffuse and roughly topographic, which has prompted some authors to suspect a modulating role of ACh on the activity of the cortical network rather than a direct synaptic role. The cholinergic system is implicated in functional, behavioural and pathological states including cognitive function, nicotine addiction, Alzheimer's disease, Tourette's syndrome, epilepsies and schizophrenia. As these processes depend on the activation of glutamatergic and GABAergic systems, the cholinergic terminals must exert their effects via the modulation of excitatory and/or inhibitory neurotransmission. However, the understanding of cholinergic modulation is complex because it is the result of a mixture of positive and negative modulation, implying that there are various types, or even subtypes, of cholinergic receptors. In this review, we summarize the current knowledge on central cholinergic systems (projections and receptors) and then aim to focus on the implications for ACh in the modulation of cortical neuronal activity.

Conclusions from a study of venous invasion in stage IV colorectal adenocarcinoma

AIMS

Venous invasion is an established predictor of prognosis in colorectal cancer (CRC). The reported incidence of venous invasion in CRC specimens varies between 10% and 89.5%, mainly as a result of interobserver variability and differences in specimen processing (for example, staining with haematoxylin and eosin (H+E) alone versus the addition of an elastic fibre stain). This study was performed with three purposes in mind, namely: (1) To assess and compare the incidence of venous invasion diagnosed on H+E stained tissue versus tissue stained with both H+E and an elastic fibre stain. (2) To estimate the inherent false negative rate associated with the diagnosis of venous invasion by histopathological evaluation of resected CRC specimens. (3) To compare the resulting data regarding incidence, quantity, site, and type of venous invasion to the pertinent literature.

METHODS

Venous invasion was assessed on sections from 81 CRCs resected from patients with synchronous distant metastases (hepatic and non-hepatic). Only stage IV tumours were studied for the following reasons: (1) it can be assumed that in all patients with distant haematogenous metastases venous invasion had occurred, thus enabling the false negative rate to be calculated; (2) there can be no dispute about the clinical relevance of the various characteristics of venous invasion identified in the tumours of patients with synchronous distant haematogenous metastases; and (3) to eliminate the effect of variance in tumour stage on the incidence of venous invasion. Initially, H+E stained sections were studied for venous invasion. Sections that were negative or questionable with regard to venous invasion were then stained with an elastic fibre stain, and a second search for venous invasion was carried out. Venous invasion was characterised by incidence, quantity, type, and site. The chi(2) test for independence was used to compare the incidence of venous invasion in colonic versus rectal and rectosigmoid primary tumours, and in patients with hepatic versus non-hepatic metastases.

RESULTS

Venous invasion was identified in 42 (51.9%) (of the 81 specimens on H+E stained sections. The addition of the elastic fibre stain enabled the diagnosis of venous invasion in 15 (38.5%) of the remaining 39 specimens, increasing the overall incidence to 57 of 81 cases (70.4%). Of the 57 positive specimens, venous invasion was minimal in 27 (47.4%), intermediate in five, (8.8%) and massive in 25 (43.9%). Only intramural veins were involved in 18 (31.6%), only extramural veins in 26 (45.6%), and both intramural and extramural veins in 13 (22.8%) of the 57 positive specimens. The filling type of venous invasion was found in 41 (71.9%), the floating type in 28 (49.1%), and the infiltrating type in six (10.5%) of the 57 positive specimens. There was no significant difference between the incidence of venous invasion in the colon (42 of 60; 70%) versus rectal and rectosigmoid tumours (15 of 21; 71.4%; p = 0.8539), nor in the incidence of venous invasion in patients with hepatic (49 of 70; 70%) versus non-hepatic (eight of 11; 72.7%) metastases (p = 0.9018).

CONCLUSIONS

The addition of an elastic fibre stain enables the identification of venous invasion in a considerable proportion of sections from CRC tumours that are falsely negative for venous invasion on H+E stain alone. The inherent chance of missing venous invasion on histopathological evaluation of CRC tumours stained with H+E and elastic fibre stains is at least 10.5%, and may be as high as 29.6%. In a large proportion of stage IV CRCs, despite the presence of synchronous distant metastases, only a minimal extent of venous invasion (that is, one to two involved veins) is demonstrable in the primary tumour. This suggests that only minimal venous invasion is required for the seeding of clinically relevant haematogenous metastases, and emphasises the careful, dedicated search for venous invasion that is required from the pathologist. Although extramural venous invasion was predominant in stage IV CRCs, in a considerable proportion of tumours (about a third) only intramural venous invasion was found. This suggests that intramural venous invasion may also seed clinically relevant haematogenous metastases, and should therefore also be considered as an indicator of poor prognosis.

ABCA1 overexpression leads to hyperalphalipoproteinemia and increased biliary cholesterol excretion in transgenic mice

The discovery of the ABCA1 lipid transporter has generated interest in modulating human plasma HDL levels and atherogenic risk by enhancing ABCA1 gene expression. To determine if increased ABCA1 expression modulates HDL metabolism in vivo, we generated transgenic mice that overexpress human ABCA1 (hABCA1-Tg). Hepatic and macrophage expression of hABCA1 enhanced macrophage cholesterol efflux to apoA-I; increased plasma cholesterol, cholesteryl esters (CEs), free cholesterol, phospholipids, HDL cholesterol, and apoA-I and apoB levels; and led to the accumulation of apoE-rich HDL1. ABCA1 transgene expression delayed 125I-apoA-I catabolism in both liver and kidney, leading to increased plasma apoA-I levels, but had no effect on apoB secretion after infusion of Triton WR1339. Although the plasma clearance of HDL-CE was not significantly altered in hABCA1-Tg mice, the net hepatic delivery of exogenous 3H-CEt-HDL, which is dependent on the HDL pool size, was increased 1.5-fold. In addition, the cholesterol and phospholipid concentrations in hABCA1-Tg bile were increased 1.8-fold. These studies show that steady-state overexpression of ABCA1 in vivo (a) raises plasma apoB levels without altering apoB secretion and (b) raises plasma HDL-C and apoA-I levels, facilitating hepatic reverse cholesterol transport and biliary cholesterol excretion. Similar metabolic changes may modify atherogenic risk in humans.

ABCA1 overexpression leads to hyperalphalipoproteinemia and increased biliary cholesterol excretion in transgenic mice

The discovery of the ABCA1 lipid transporter has generated interest in modulating human plasma HDL levels and atherogenic risk by enhancing ABCA1 gene expression. To determine if increased ABCA1 expression modulates HDL metabolism in vivo, we generated transgenic mice that overexpress human ABCA1 (hABCA1-Tg). Hepatic and macrophage expression of hABCA1 enhanced macrophage cholesterol efflux to apoA-I; increased plasma cholesterol, cholesteryl esters (CEs), free cholesterol, phospholipids, HDL cholesterol, and apoA-I and apoB levels; and led to the accumulation of apoE-rich HDL1. ABCA1 transgene expression delayed 125I-apoA-I catabolism in both liver and kidney, leading to increased plasma apoA-I levels, but had no effect on apoB secretion after infusion of Triton WR1339. Although the plasma clearance of HDL-CE was not significantly altered in hABCA1-Tg mice, the net hepatic delivery of exogenous 3H-CEt-HDL, which is dependent on the HDL pool size, was increased 1.5-fold. In addition, the cholesterol and phospholipid concentrations in hABCA1-Tg bile were increased 1.8-fold. These studies show that steady-state overexpression of ABCA1 in vivo (a) raises plasma apoB levels without altering apoB secretion and (b) raises plasma HDL-C and apoA-I levels, facilitating hepatic reverse cholesterol transport and biliary cholesterol excretion. Similar metabolic changes may modify atherogenic risk in humans.

High-affinity Zn block in recombinant N-methyl-D-aspartate receptors with cysteine substitutions at the Q/R/N site

In ionotropic glutamate receptors, many channel properties (e.g., selectivity, ion permeation, and ion block) depend on the residue (glutamine, arginine, or asparagine) located at the tip of the pore loop (the Q/R/N site). We substituted a cysteine for the asparagine present at that position in both NR1 and NR2 N-methyl-D-aspartate (NMDA) receptor subunits. Under control conditions, receptors containing mutated NR1 and NR2 subunits show much smaller glutamate responses than wild-type receptors. However, this difference disappears upon addition of heavy metal chelators in the extracellular bath. The presence of cysteines at the Q/R/N site in both subunits of NR1/NR2C receptors results in a 220,000-fold increase in sensitivity of the inhibition by extracellular Zn. In contrast with the high-affinity Zn inhibition of wild-type NR1/NR2A receptors, the high-affinity Zn inhibition of mutated NR1/NR2C receptors shows a voltage dependence, which resembles very much that of the block by extracellular Mg. This indicates that the Zn inhibition of the mutated receptors results from a channel block involving Zn binding to the thiol groups introduced into the selectivity filter. Taking advantage of the slow kinetics of the Zn block, we show that both blocking and unblocking reactions require prior opening of the channel.

Peritonitis caused by a ruptured infected mesenteric cyst

Perforation of a mesenteric cyst is a very rare complication of a very unusual lesion. Acute presentation is the rule in half of all affected children. Ultrasonography and computed tomography are the best preoperative diagnostic tools. The treatment of choice is an urgent laparotomy and complete cyst removal. Results are good in cases that are operated on in a timely manner.

Hyperbaric oxygen for children with cerebral palsy: a randomised multicentre trial. HBO-CP Research Group

BACKGROUND

The use of hyperbaric oxygen for children with cerebral palsy has spread worldwide, despite little scientific evidence of efficacy. We did a randomised trial to assess the efficacy and side-effects of this form of therapy in children with cerebral palsy.

METHODS

111 children with cerebral palsy aged 3-12 years were randomly assigned hyperbaric oxygen (n=57) or slightly pressurised room air (n=54). All children received 40 treatments over 2 months. Hyperbaric oxygen treatment was 1 h in 100% oxygen at 1.75 atmospheres absolute (ATA); children on slightly pressurised air received air at 1.3 ATA (the lowest pressure at which pressure can be felt, thereby ensuring the maintenance of masking). The main outcome measure was gross motor function. Secondary outcomes included performance in activities of daily living, attention, working memory, and speech.

FINDINGS

For all outcomes, both groups improved over the course of the study, but without any difference between the two treatments. The score on the global gross motor function measure increased by 3.0% in the children on slightly pressurised air and 2.9% in those on hyperbaric oxygen. The mean difference between treatments was -0.40 (95% CI -1.69 to 0.90, p=0.544). Other changes were seen in speech, attention, memory, and functional skills. Ear problems occurred in 27 children treated by hyperbaric oxygen and in 15 treated with hyperbaric air (p=0.004).

INTERPRETATION

In this study, hyperbaric oxygen did not improve the condition of children with cerebral palsy compared with slightly pressurised air. The improvement seen in both groups for all dimensions tested deserves further consideration.

Cytotoxic T lymphocytes are activated following myocardial infarction and can recognize and kill healthy myocytes in vitro

The damage of myocardial infarction (MI) is often progressive. A possible mechanism for subsequent myocardial damage and heart failure after MI is immune response against cardiac self-antigens. The purpose of our study was to test the hypothesis that cytotoxic T lymphocytes are activated following acute MI and may have a role in producing further myocardial damage. Rats were allocated into three experimental groups: acute MI, Sham MI and non-operated control. One, two and three weeks after surgery, lymphocytes were obtained from rat spleens and incubated with neonatal cardiac myocytes. Lymphocyte proliferation was assessed by a thymidine incorporation assay and calculated as proliferation index (PI). Myocyte destruction was measured by a crystal-violet staining assay and expressed as percentage of cell destruction. Proliferation index was significantly higher among lymphocytes obtained from MI animals (44. 3+/-5.8 and 44.9+/-5.1, at 2 and 3 weeks after MI, respectively) than sham MI (29.3+/-5.3, 27.1+/-4.7) (P<0.05) or control animals (17.1+/-2.5, 16.2+/-2.8) (P=0.03). Cytotoxic activity of the MI lymphocytes against the cultured cardiomyocytes was significantly higher 2 and 3 weeks after MI, (36.4+/-7.3%, 69.3+/-4.9%) compared to sham MI (17.9+/-3.14%, 36.6+/-5.3%) (P<0.001) and control animals respectively (13.3+/-5.4%, 17.4+/-6.1%) (P<0.001). The cytotoxic activity against healthy cardiomyocytes was myocyte-specific, induced by CD8 lymphocytes and major-histocompatibility complex (MHC) restricted. Cytotoxic T lymphocytes (CD8) are activated following MI and can recognize and kill normal cardiomyocytes in vitro. The newly described pathophysiological insights may provide novel oportunities to prevent death of non-ischemic cardiomyocytes and heart failure following myocardial infarction.

Pleomorphic hyalinizing angiectatic tumor of soft parts: immunohistochemical study including the expression of vascular endothelial growth factor

We report morphologic, flow cytometric, and immunohistochemical findings in two cases of pleomorphic hyalinizing angiectatic tumor of soft parts. Both patients were middle-aged women with subcutaneous lesions located in the lower extremity. The tumors consisted of sheets of spindled and pleomorphic cells with frequent intranuclear pseudoinclusions associated with clusters of ectatic vessels surrounded by prominent perivascular hyaline material. Numerous, nonhyalinized vessels were also present, mostly in the peripheral areas of the lesions. Some of these vessels had their walls permeated by numerous small capillaries. Immunostaining for vascular endothelial growth factor (VEGF), a secreted protein that has been implicated in tumor-associated angiogenesis, demonstrated positive staining in both tumoral and endothelial cells. Tumor cells were also reactive to vimentin and CD34. Focal positivity for CD99 and factor XIIIa was also present. Flow cytometry yielded a diploid DNA histogram with S-phase fraction of 7%. Our findings corroborate those from previously reported cases. They further suggest that angiogenesis and the angiogenic factor VEGF may play a role in the development of this peculiar tumor.

Multinucleated stromal cells of the anal mucosa: a common finding

AIMS

To document the presence, morphology, immunophenotype and ultrastructure of multinucleated stromal cells within the anal mucosa and to discuss possible pathogenetic mechanisms for this occurrence.

METHODS AND RESULTS

Multiple sections of normal anal mucosa from 30 abdominoperineal resection specimens were analysed by light microscopic, electron microscopic and immunohistochemical methods. Multinucleated stromal cells were found in 22 cases (73%). They contained two to five nuclei, arranged in a linear fashion or in a rosette or grape-like pattern. They stained positive for vimentin and negative for actin, desmin and oestrogen/progesterone receptors. Ultrastructural examination confirmed their fibroblastic lineage. Mast cells were frequently observed in the immediate vicinity of mono- and multinucleated cells.

CONCLUSIONS

Multinucleated stromal cells are a common occurrence in the normal anal mucosa. They should not be misinterpreted as neoplastic cells. Mast cells may play a role in their morphogenesis.

Lymph-node-based malignant lymphoma and reactive lymphadenopathy in eosinophilic fasciitis

BACKGROUND

Lymph node enlargement in patients with eosinophilic fasciitis is a rare occurrence and its clinical significance is unknown.

METHODS

The literature and authors' registries were searched for eosinophilic fasciitis associated with lymphadenopathy. Clinical data, time sequence of appearance of either disorder, and pathological diagnoses were analyzed.

RESULTS

Six patients presenting with eosinophilic fasciitis had a lymph-node-based lymphoma and 4 patients had a reactive lymphadenopathy. The patients with lymphoma were elderly and the subcutaneous induration preceded the lymphadenopathy by 2 to 36 months. The patients with eosinophilic fasciitis and reactive lymphadenopathy were young and the onset of subcutaneous induration and lymph node enlargement coincided with one another. Favorable response of the eosinophilic fasciitis to prednisone therapy was attained in 3 of 3 patients with reactive lymphadenopathy and in 4 of the 6 cases with lymphoma.

CONCLUSIONS

Eosinophilic fasciitis is rarely associated with clinically significant lymph node enlargement. Subcutaneous induration preceding the lymphadenopathy by 6 months or more, especially in elderly patients, suggests an underlying lymphoma. A favorable response of the subcutaneous induration to prednisone treatment does not exclude the diagnosis of lymphoma; therefore, it does not supersede the need of a pathological evaluation. A lymph node biopsy is mandatory in all cases.

[Severe hypercalcemia due to renal transitional cell carcinoma]

Hypercalcemia is a common metabolic disorder, especially in the elderly. The most common etiologies are hyperparathyroidism or malignancy, most often of the lung, breast, kidney or hematological system. Because hypercalcemia is an uncommon manifestation in urinary tract epithelial tumors, especially those of the renal pelvis, we present a man aged 62 years with hypercalcemia due to renal transitional cell carcinoma.

Toxoplasma infection in systemic lupus erythematosus mimicking lupus cerebritis

An opportunistic infection is a known, although under-diagnosed, complication of systemic lupus erythematosus (SLE). A 48-year-old woman with a recent diagnosis of SLE was admitted to the hospital because of a fever, confused state, and convulsive episode. Her symptoms were interpreted as being compatible with lupus cerebritis. Treatment with methylprednisolone resulted in a temporary improvement in the patient's condition. Nevertheless, during the next few weeks, her physical and mental condition deteriorated, and she died of massive pulmonary emboli. An autopsy revealed no signs of lupus cerebritis; however, disseminated cerebral toxoplasmosis was found. Cerebral toxoplasmosis is a rare complication of SLE that may be misdiagnosed as lupus cerebritis.

Microcalcifications in the anterior pituitary gland of the fetus and the newborn: a histochemical and immunohistochemical study

Calcified concretions are a normal and constant finding in the anterior pituitary gland of fetuses and newborns. Their light and electron microscopic characteristics have been recently reported by the authors. In this study, undecalcified and decalcified sections from 20 neonatal and 60 fetal anterior pituitary glands were studied by histochemical and immunohistochemical methods to further clarify their nature and mechanism of formation. All the glands revealed homogeneous and/or laminar calcifications located either within the interstitium or follicular structures. They were composed of a diastase-resistant periodic acid-Schiff-positive carbohydrate-rich matrix. The Feulgen method for DNA was negative. Their core frequently reacted to Alcian blue and epithelial membrane antigen (EMA). EMA also stained the apical membranes of adjacent epithelial cells. Other immunostains (vimentin, keratin, and pituitary hormones) were negative. The positive staining for Alcian blue and EMA and the negative staining with the Feulgen method for DNA suggest that the core of the calcifications consists of acidic mucosubstances and EMA-positive proteinaceous material previously secreted by viable pituitary cells. The EMA-negative periphery of the concretions probably develops from further extracellular peripheral mineralization that leads to larger, sometimes laminated psammoma bodies. The occurrence of pituitary calcifications in states of adult physiological and pathological hyperprolactinemia suggests that the marked proliferation of lactotrophs occurring during the fetal life play an important role in the pathogenesis of the fetal and neonatal concretions.

Effects of hyperbaric oxygen therapy on children with spastic diplegic cerebral palsy: a pilot project

Hyperbaric oxygen (HBO2) therapy for children with cerebral palsy (CP) is not new. Research documenting the effects in this population has been anecdotal. We evaluated the effects of HBO2 therapy for 25 children (X = 5.6 +/- 1.6 yr) with a functional diagnosis of spastic diplegic CP. Pre- and post-HBO2 evaluations consisted of the following measures: gross motor function measure (GMFM), fine motor function (Jebsen test for hand function), spasticity (modified Ashworth scale), video analysis, and parental questionnaire. The protocol for HBO2 therapy was 20 treatments of 95% oxygen at 1.75 atm abs for 60 min. The Wilcoxon matched-pairs signed-rank test for non-parametric measures was used to compare pre- and post-treatment data. Results showed improved gross motor function in three of the five items in the GMFM test, improved fine motor function in three of the six hand tests, reduced spasticity in three of four muscle groups when assessed by a physician specializing in CP, and improvements for four of nine questions posed to parents.

The role of hepatic lipase in lipoprotein metabolism and atherosclerosis

In addition to its traditional role in the hydrolysis of lipoprotein triglycerides and phospholipids, recent studies have implicated hepatic lipase in other aspects of cellular lipid and/or lipoprotein metabolism and atherosclerosis. Hepatic lipase may serve as a ligand that mediates the interaction of lipoproteins to cell surface receptors and/or proteoglycans as well as modulating aortic lesion development in different animal models. Over the past several years significant advances have been made in our understanding of new, alternative mechanisms by which hepatic lipase may modulate lipoprotein metabolism and the development of atherosclerosis in vivo.

Mucicarminophilic histiocytosis (benign signet-ring cells) and hyperplastic mesothelial cells: two mimics of metastatic carcinoma within a single lymph node

We describe a unique case of simultaneous signet-ring histiocytes containing polyvinylpyrrolidone (mucicarminophilic histiocytosis) and hyperplastic mesothelial cells within a single supraclavicular lymph node. Both types of cells expanded the nodal sinuses and were initially suspected of being metastatic carcinoma. Histologic features suggested the correct diagnoses, which were confirmed by histochemical and immunohistochemical staining. It is important for pathologists to be aware of these phenomena, so as to avoid a misdiagnosis of metastatic carcinoma.

Effect of advanced glycation end product-modified albumin on tissue factor expression by monocytes. Role of oxidant stress and protein tyrosine kinase activation

Diabetes is associated with a hypercoagulable state that contributes to macrovascular complications, including cardiovascular events. The glycation reaction, a consequence of chronic hyperglycemia, has also been implicated in the pathogenesis of diabetic complications. Glycated proteins have receptors on monocytes and generate reactive oxygen species that can regulate the expression of a number of genes. As abnormal monocyte expression of tissue factor (TF), the main initiator of the coagulation cascade, is responsible for thrombosis in a number of clinical settings, we studied the effect of glycated albumin on monocyte TF expression. Mononuclear cells were incubated with glycated albumin for 24 hours, and monocyte TF activity was measured with a plasma recalcification time assay; TF antigen was measured by ELISA and TF mRNA by RT-PCR. Glycated albumin induced blood monocyte expression of the procoagulant protein TF at the mRNA level. Oxidative stress appeared to be involved in this effect, as the antioxidant N-acetylcysteine diminished TF mRNA accumulation in stimulated monocytes. Hydroxyl radicals, which may be generated inside cells from H2O2 via the Fenton reaction, also appeared to be involved in this effect, as hydroxyl radical scavengers downregulated TF activity and antigen levels (but not TF mRNA). Finally, the involvement of activated protein tyrosine kinase in the transmission of the signal from the membrane to the nucleus was suggested by the inhibitory effect of herbimycin A. These results point to a new mechanism for the hypercoagulability often described in diabetic patients and suggest that antioxidants or protein tyrosine kinase inhibitors might be of therapeutic value in this setting.

Effect of L-arginine on systemic and renal haemodynamics in salt-sensitive patients with essential hypertension

In response to a high sodium (Na+) intake, salt-sensitive patients with hypertension retain more Na+ and manifest a greater rise in arterial pressure than salt-resistant patients. Because there is limited information regarding the role of nitric oxide (NO) in salt-sensitivity we examined the effects of L-arginine (500 mg/kg, i.v. for 30 min) on mean arterial pressure and renal haemodynamics in 21 hypertensive and five normotensive African-Americans. At the end of L-arginine infusion mean arterial pressure fell more in salt-sensitive (-11.5 +/- 2.5) than in salt-resistant (-3.7 +/- 1.5 mm Hg) and control subjects (-3.2 +/- 3.8 mm Hg). At the end of L-arginine infusion effective renal plasma flow (ERPF) increased more (P < 0.05) in controls (+108 +/- 13.9 ml/min/1.73 m2) than in salt-resistant (+55 +/- 16.0 ml/min/1.73 m2) and salt-sensitive patients (+22 +/- 21.5 ml/min/1.73 m2). This study has shown that salt-sensitive African-Americans manifest different systemic and renal haemodynamic responses to L-arginine than salt-resistant patients and controls. The fall in mean blood pressure following L-arginine was greater in salt-sensitive than in salt-resistant patients and controls, whereas the increase in ERPF was reduced in salt-sensitive compared to salt-resistant and normal subjects. The data are in keeping with the notion that a defect in NO production may participate to the genesis of blood pressure sensitivity to salt.

[Giant mesenteric cyst mimicking ascites]

Mesenteric cyst is a rare, benign lesion. A 59-year-old woman was admitted with abdominal distension. Physical examination and abdominal ultrasound indicated remarkable ascites. Aspiration revealed a clear transudate and computerized tomography showed a giant mesenteric cyst. At operation the cyst was removed. Giant mesenteric cysts can mimic ascites. This diagnosis should be included in the differential diagnosis of abdominal distension, even when ultrasound examination indicates ascites.

Structure and pharmacological properties of a molluscan glutamate-gated cation channel and its likely role in feeding behavior

We describe the isolation of a molluscan (Lymnaea stagnalis) full-length complementary DNA that encodes a mature polypeptide (which we have named Lym-eGluR2) with a predicted molecular weight of 105 kDa that exhibits 44-48% identity to the mammalian kainate-selective glutamate receptor GluR5, GluR6, and GluR7 subunits. Injection of in vitro-transcribed RNA from this clone into Xenopus laevis oocytes results in the robust expression of homo-oligomeric cation channels that can be gated by L-glutamate (EC50 = 1.2 +/- 0.3 micron) and several other glutamate receptor agonists; rank order of potency: glutamate >> kainate > ibotenate > AMPA. These currents can be blocked by the mammalian non-NMDA receptor antagonists 6,7-dinitroquinoxaline-2,3-dione, 6-cyano-7-nitroquinoxaline-2,3-dione, and 1-(4-chlorobenzoyl)piperazine-2,3-dicarboxylic acid. Ionic-replacement experiments have shown that the agonist-induced current is carried entirely by sodium and potassium ions. In situ hybridization has revealed that the Lym-eGluR2 transcript is present in all 11 ganglia of the Lymnaea CNS, including the 4-cluster motorneurons within the paired buccal ganglia. The pharmacological properties and deduced location of Lym-eGluR2 are entirely consistent with it being (a component of) the receptor, which has been identified previously on buccal motorneurons, that mediates the excitatory effects of glutamate released from neurons within the feeding central pattern generator.

Stable functional expression of the adult subtype of human muscle acetylcholine receptor following transfection of the human rhabdomyosarcoma cell line TE671 with cDNA encoding the epsilon subunit

The human rhabdomyosarcoma cell line TE671 expresses the foetal subtype of muscle acetylcholine receptor (AChR). By transfecting TE671 cells with cDNA encoding the human muscle AChR epsilon subunit under the control of the cytomegalovirus promoter we have established a stable cell clone that, in addition, constitutively expresses the adult AChR subtype. Both subtypes are inserted into the plasma membrane and demonstrate their respective characteristic single channel properties. The level of expression of the adult AChR subtype is two- to three-fold higher than that of the foetal subtype. The new cell clone provides a relatively abundant source of human adult AChR for immunological and pharmacological investigations.

Axillary involvement in pediatric Kikuchi's disease

We report the first Israeli pediatric case of Kikuchi's disease in a 10-year-old male. He was hospitalized for evaluation of migrating arthralgia and fever. Axillary adenopathy was the main physical finding. A biopsy showed a histiocytic necrotizing lymphadenitis. Diagnosis, therapeutic options and the clinical significance of Kikuchi's disease are discussed. Kikuchi's disease should be considered in the differential diagnosis of fever of unknown origin in children, even in the absence of cervical adenopathy. A long follow-up is advised because of possible links with systemic lupus erythematosus and to detect eventual late recurrences.

A nicotinic acetylcholine receptor subunit from insect brain forms a non-desensitising homo-oligomeric nicotinic acetylcholine receptor when expressed in Xenopus oocytes

The locust alpha-like nicotinic receptor subunit alpha L1 was expressed in Xenopus oocytes. Small but reproducible currents were elicited by application of high concentrations of nicotine, demonstrating that alpha L1 is capable of forming homo-oligomeric channels. Nicotine-evoked currents were blocked by alpha-bungarotoxin and methyllycaconitine. Comparison with chick alpha 7 receptors showed that the two receptors differ with respect to nicotine sensitivity and time course of evoked currents. Nicotine dose-response curves gave EC50 values of 24 and 830 microM for alpha 7 and alpha L1 respectively. Whereas alpha 7 responses showed characteristic fast onset and rapid desensitization within 3 s, alpha L1 currents displayed a slow onset and showed no tendency to desensitize during 45 s of agonist application. Thus alpha L1 is a novel nicotine subunit for the further exploration of structure-function relationships of ligand-gated ion channels. The question of the subunit composition of native insect receptors remains open.

[Uncommon manifestations of schistosomal colitis in African immigrants]

Schistosomiasis is rare in Israel but very common in Africa. The recent Ethiopian immigration has brought us cases of parasitic diseases unfamiliar to Israeli physicians. 3 cases with uncommon manifestations of colonic schistosomiasis are described. The first had bloody diarrhea for 4 years. The second had co-infection with Salmonella D. The third was diagnosed as having schistosomal colitis on routine sigmoidoscopy, which was performed following diagnosis of rectal carcinoma in her brother.