Expanding Chemical Frontiers: Approaches for Generating Diverse and Bioactive Natural Product-Like Compounds Libraries from Extracts

The realms of natural products and synthetic compounds exhibit distinct chemical spaces that not only differ but also complement each other. While the convergence of these two domains has been explored through semisynthesis and conventional pharmacomodulation endeavours applied to natural frameworks, a recent and innovative approach has emerged that involves the combinatorial generation of libraries of 'natural product-like compounds' (NPLCs) through the direct synthetic derivatization of natural extracts. This has led to the production of numerous NPLCs that incorporate structural elements from both their natural (multiple saturated rings, oxygen content, chiral centres) and synthetic (aromatic rings, nitrogen and halogen content, drug-like properties) precursors. Through careful selection of extracts and reagents, specific bioactivities have been achieved, and this strategy has been deployed in various ways, showing great promise without reaching its full potential to date. This review seeks to provide an overview of reported examples involving the chemical engineering of extracts, showcasing a spectrum of natural product alterations spanning from simple substitutions to complete scaffold remodelling. It also includes an analysis of the accomplishments, perspectives and technical challenges within this field.

Aurones and derivatives as promising New Delhi metallo-β-lactamase (NDM-1) inhibitors

Bacterial resistance is undoubtedly one of the main public health concerns especially with the emergence of metallo-β-lactamases (MBLs) able to hydrolytically inactivate β-lactam antibiotics. Currently, there are no inhibitors of MBLs in clinical use to rescue antibiotic action and the New Delhi metallo-β-lactamase-1 (NDM-1) is still considered as one of the most relevant targets for inhibitor development. Following a fragment-based strategy to find new NDM-1 inhibitors, we identified aurone as a promising scaffold. A series of 60 derivatives were then evaluated and two of them were identified as promising inhibitors with Ki values as low as 1.7 and 2.5 µM. Moreover, these two most active compounds were able to potentiate meropenem in in vitro antimicrobial susceptibility assays. The molecular modelling provided insights about their likely interactions with the active site of NDM-1, thus enabling further improvement in the structure of this new inhibitor family.

Epstein-Barr Virus Encephalitis: A Review of Case Reports from the Last 25 Years

Although uncommon, Epstein-Barr virus-related neurological disorders represent the seventh most frequent cause of infectious encephalitis in adults. The limited number of publications on EBV encephalitis mainly document isolated clinical cases. This study aimed to summarize published data on EBV encephalitis. A systematic literature search identified 97 EBV encephalitis cases. In the selected cases, EBV-related neurological disorders manifested as lymphocytic pleocytosis in the cerebrospinal fluid (CSF) with moderate hyperproteinorachia. The EBV PCR test was positive in 87% of the CSF samples, with wide-ranging viral loads. When encephalitis occurred in the context of past EBV infections, all of the EBV PCR tests on CSF samples were positive. On the contrary, negative EBV PCR tests on CSF samples occurred only in the context of primary infections. EBV PCR was rarely carried out on blood samples, contributing minimally to the diagnosis. For the treatment of EBV encephalitis, Aciclovir was used alone in 29% of cases, and in association with other drugs in 40% of cases. Ganciclovir (30%), corticoids (52%), and immunoglobulins (15%) were mainly used in association with other drugs. Cerebral imaging was abnormal in 69% of cases, mostly in the cerebellum and basal ganglia. This work highlights that the EBV PCR test on CSF samples is currently the main laboratory diagnostic test to diagnose EBV encephalitis. This diagnostic test is useful; however, it is imperfect. New complementary diagnostic tools, approved treatments, and standardized practices could improve patient management.

Substrate-bound and substrate-free outward-facing structures of a multidrug ABC exporter

Multidrug ABC transporters translocate drugs across membranes by a mechanism for which the molecular features of drug release are so far unknown. Here, we resolved three ATP-Mg²⁺-bound outward-facing conformations of the Bacillus subtilis (homodimeric) BmrA by x-ray crystallography and single-particle cryo-electron microscopy (EM) in detergent solution, one of them with rhodamine 6G (R6G), a substrate exported by BmrA when overexpressed in B. subtilis. Two R6G molecules bind to the drug-binding cavity at the level of the outer leaflet, between transmembrane (TM) helices 1-2 of one monomer and TM5'-6' of the other. They induce a rearrangement of TM1-2, highlighting a local flexibility that we confirmed by hydrogen/deuterium exchange and molecular dynamics simulations. In the absence of R6G, simulations show a fast postrelease occlusion of the cavity driven by hydrophobicity, while when present, R6G can move within the cavity, maintaining it open.

Substrate-bound and substrate-free outward-facing structures of a multidrug ABC exporter

Multidrug ABC transporters translocate drugs across membranes by a mechanism for which the molecular features of drug release are so far unknown. Here, we resolved three ATP-Mg²⁺-bound outward-facing conformations of the Bacillus subtilis (homodimeric) BmrA by x-ray crystallography and single-particle cryo-electron microscopy (EM) in detergent solution, one of them with rhodamine 6G (R6G), a substrate exported by BmrA when overexpressed in B. subtilis. Two R6G molecules bind to the drug-binding cavity at the level of the outer leaflet, between transmembrane (TM) helices 1-2 of one monomer and TM5'-6' of the other. They induce a rearrangement of TM1-2, highlighting a local flexibility that we confirmed by hydrogen/deuterium exchange and molecular dynamics simulations. In the absence of R6G, simulations show a fast postrelease occlusion of the cavity driven by hydrophobicity, while when present, R6G can move within the cavity, maintaining it open.

β-Carboline as a Privileged Scaffold for Multitarget Strategies in Alzheimer's Disease Therapy

The natural β-carboline alkaloids display similarities with neurotransmitters that can be favorably exploited to design bioactive and bioavailable drugs for Alzheimer's disease (AD) therapy. Several AD targets are currently and intensively being investigated, divided in different hypotheses: mainly the cholinergic, the amyloid β (Aβ), and the Tau hypotheses. To date, only symptomatic treatments are available involving acetylcholinesterase and NMDA inhibitors. On the basis of plethoric single-target structure-activity relationship studies, the β-carboline scaffold was identified as a powerful tool for fostering activity and molecular interactions with a wide range of AD-related targets. This knowledge can undoubtedly be used to design multitarget-directed ligands, a highly relevant strategy preferred in the context of multifactorial pathology with intricate etiology such as AD. In this review, we first individually discuss the AD targets of the β-carbolines, and then we focus on the multitarget strategies dedicated to the deliberate design of new efficient scaffolds.

Piperidinyl-embeded chalcones possessing anti PI3Kδ inhibitory properties exhibit anti-atopic properties in preclinical models

Phosphatidylinositide 3-kinases (PI3Ks) are widely expressed enzymes involved in membrane signalization pathways. Attempts to administer inhibitors with broad activity against different isoforms have failed due to toxicity. Conversely the PI3Kδ isoform is much more selectively expressed, enabling therapeutic targeting of this isoform. Of particular interest PI3Kδ is expressed in human basophils and its inhibition has been shown to reduce anti-IgE induced basophil degranulation, suggesting that PI3Kδ inhibitors could be useful as anti-allergy drugs. Herein, we report for the first time the activity of compounds derived from chalcone scaffolds as inhibitors of normal human basophil degranulation and identified the most active compound with anti-PI3Kδ properties that was investigated in preclinical models. Compound 18, namely 1-[2-hydroxy-4,6-dimethoxy-3-(N-methylpiperidin-4-yl)phenyl]-3-(2,4,6-trimethoxyphenyl)-prop-2-en-1-one, was found to inhibit normal human basophil degranulation in a dose-dependent manner. In a murine model of ovalbumin-induced asthma, compound 18 was shown to reduce expiratory pressure while its impact on the inflammatory infiltrate in alveolar lavage and total lung was dependent on the route of administration. In a DNFB-induced model of atopic dermatitis compound 18 administered systemically proved to be as potent as topical betamethasone. These results support the anti-atopic and allergic properties of the title compound and warrant further clinical development.

Traditional uses, phytochemistry and pharmacological properties of African Nauclea species: A review

ETHNOPHARMACOALOGICAL RELEVANCE

The genus Nauclea in Africa comprises seven species. Among them, N. latifolia, N. diderrichii and N. pobeguinii are widely used by the local population in traditional remedies. Preparation from various parts of plants (e.g. roots, bark, leaves) are indicated by traditional healers for a wide range of diseases including malaria, pain, digestive ailments or metabolic diseases.

MATERIALS AND METHODS

A literature search was conducted on African species of the genus Nauclea using scientific databases such as Google Scholar, Pubmed or SciFinder. Every document of ethnopharmacological, phytochemical or pharmacological relevance and written in English or French were analyzed.

RESULTS AND DISCUSSION

The Nauclea genus is used as ethnomedicine all along sub-Saharan Africa. Several local populations consider Nauclea species as a major source of remedies for malaria. In this regard, two improved traditional medicines are currently under development using extracts from N. latifolia and N. pobeguinii. Concerning the chemical composition of the Nauclea genus, indoloquinolizidines alkaloids could be considered as the major class of compounds as they are reported in every analyzed Nauclea species, with numerous structures identified. Based on traditional indications a considerable amount of pharmacological studies were conducted to ensure activity and attempt to link them to the presence of particular compounds in plant extracts.

CONCLUSION

Many experimental studies using plant extracts of the African species of the genus Nauclea validate traditional indications (e.g. malaria and pain). However, bioactive compounds are rarely identified and therefore, there is a clear need for further evaluations as well as for toxicity experiments. The sustainability of these plants, especially of N. diderrichii, a threatened species, should be kept in mind to adapt local uses and preparation modes of traditional remedies.

Occurrences, biosynthesis and properties of aurones as high-end evolutionary products

Recent years have witnessed a considerable renewed interest for the uncommon flavonoid class of aurones. The characterization of two major biosynthetic machineries involved in their biosynthesis in flowers has encouraged the revival of phytochemical studies and identification of original structures, a process started almost seventy-five years ago. This review draws up an exhaustive map of natural occurrences of aurones their biosynthetic pathways and roles, with the aim to link their original structural properties among flavonoids to their place in evolution and the selective advantages they bring to some of the most advanced taxa in the plant kingdom.

Disruption of Fibers from the Tau Model AcPHF6 by Naturally Occurring Aurones and Synthetic Analogues

The formation of tau aggregates is strongly linked to the neurodegenerative process in tauopathies such as Alzheimer's disease (AD). Yet only a few molecules have shown to efficiently prevent the in vitro formation of those aggregates, and the identification of such molecules is still an ongoing interest in a therapeutic context. Herein, we report the in vitro evaluation of a series of aurones against the fibrillation of the tau-derived hexapeptide AcPHF6 model. Using thioflavin T-based fluorescence assays, circular dichroism and atomic force microscopy, we showed that aurones are capable of efficiently interacting with the tau-derived hexapeptide. Importantly, this work reveals a significant activity observed for polyhydroxylated aurones. In particular, aurone 23 displayed an almost complete inhibition of fibers formation as shown by AFM at a peptide/inhibitor 1:1 ratio. It is similar to that observed for myricetin, a polyphenolic compound, well-known to prevent the in vitro elongation of tau fibers. Moreover, a tetrahydroxylated isomer, compound 24, was shown as a chemical probe of fibers rather than an inhibitor. Consequently, these results highlight aurones as a new promising scaffold to interfere with tau aggregation for both treatment and diagnosis of AD.

Arylthiosemicarbazones as antileishmanial agents

Based on a screening process, we targeted substituted thiosemicarbazone as potential antileishmanial agents. Our objective was to identify the key structural elements contributing to the anti-parasite activity that might be used for development of effective drugs. A series of 32 compounds was synthesized and their efficacy was evaluated against the clinically relevant intracellular amastigotes of Leishmania donovani. From these, 22 compounds showed EC50 values below 10 μM with the most active derivative (compound 14) showing an EC50 of 0.8 μM with very low toxicity on two different mammalian cell lines. The most relevant structural elements required for higher activity indicate that the presence of a fused bicyclic aromatic ring such as a naphthalene bearing an alkyl or an alkoxy group substituent are prerequisites. Owing to the easy synthesis, high activity and low toxicity, the most active compounds could be considered as a lead for further development.

2-Indolylmethylenebenzofuranones as first effective inhibitors of ABCC2

ABC-transporters play a vital role in drugs bioavailability. They prevent intracellular accumulation of toxic compounds, rendering them a major defense mechanism against harmful substances. In this large family, ABCC2 is an apical efflux pump representing about 10% of all membrane proteins in liver and small intestine, and up to 25% in colon. In these tissues, ABCC2 plays a major role in the pharmacokinetics and pharmacodynamics of endo- and xenobiotics. To gain insight in the function of this crucial protein, we have investigated and developed the first effective inhibitors of this pump. Firstly, we set up a cellular flow cytometry assay for monitoring the drug efflux carried out by ABCC2, and used it for the screening of chemical libraries derived from several chemical classes. We found that 2-indolylmethylenebenzofuranone derivatives as promising candidates. Optimization of the hits provided new compounds that inhibit ABCC2 in the micromolar range, making them the first potent ABCC2 inhibitors reported so far. Such compounds would constitute valuable tools to further investigate the role of ABCC2 in the pharmacokinetics and pharmacodynamics of drugs.

Chemical composition of the pods of Albizia polyphylla

In this study, we report for the first time the presence of alkaloids belonging to β-carboline type in the pods of the endemic Albizia polyphylla from Madagascar. Three major alkaloids were isolated and structurally identified as: 1-methyl-β-carboline, (+)-(R)-1-methyl-1,2,3,4-tetrahydro-β-carboline and (-)-(S)-1,2-dimethyl-1,2,3,4-tetrahydro-β-carboline.

Antibiotic drugs aminoglycosides cleave DNA at abasic sites: shedding new light on their toxicity?

Abasic sites are probably the most common lesions in DNA resulting from the hydrolytic cleavage of glycosidic bonds that can occur spontaneously and through DNA alkylation by anticancer agents, by radiotherapy, and during the repair processes of damaged nucleic bases. If not repaired, the abasic site can be mutagenic or lethal. Thus, compounds able to specifically bind and react at abasic sites have attracted much attention for therapeutic and diagnostic purposes. Here, we report on the efficient cleavage activity of characteristic antibiotic drugs of the major aminoglycosides (AG) family at abasic sites introduced either by depurination in a plasmidic DNA or site specifically in a synthetic oligonucleotide. Among the antibiotic AG drugs selected for this study, neomycin B is the most efficient (a 0.1 μM concentration induces 50% cleavage of an abasic site containing DNA). This cleavage activity could be related to aminoglycoside toxicity but also find medicinal applications through potentiation of cancer radiotherapy and chemotherapy with alkylating drugs. In the search for antibiotic and antiviral agents, we have previously described the synthesis of derivatives of the small aminoglycoside neamine, which corresponds to rings I and II of neomycin B constituted of four rings. The cleavage activity at abasic sites of four of these neamine derivatives is also reported in the present study. One of them appeared to be much more active than the parent compound neamine with cleavage efficiency close to that of neomycin.

Sialoblastoma of salivary glands in children: chemotherapy should be discussed as an alternative to mutilating surgery

Sialoblastoma is a very rare congenital salivary gland tumor. No consensus has been reached concerning the treatment of this tumor due to its rarity. The treatment of reference is surgery, which can be mutilating, in the case of a locally invasive tumor. The treatment of metastatic disease is also controversial. The authors report a new case of a 6-year-old girl with a progressively growing left parotid mass since birth. The first cytological diagnosis was that of pleomorphic adenoma. Due to local progression, superficial parotidectomy was performed at the age of 3.5 years and revealed a diagnosis of sialoblastoma. Six months later, local recurrence and lung metastasis were treated by neoadjuvant chemotherapy with a very good partial response on the local recurrence and the lung metastasis, allowing complete parotidectomy with sacrifice of the facial nerve. Bilateral lung biopsies after adjuvant chemotherapy showed total necrosis. No recurrence was observed with a follow-up of 1 year. This case and a review of the literature confirm the very good chemosensitivity of this tumor and argue in favor of neoadjuvant chemotherapy for locally invasive tumors rather than extensive mutilating surgery.

Medullary thyroid carcinoma identified within the first year of life in children with hereditary multiple endocrine neoplasia type 2A (codon 634) and 2B

CONTEXT

Early prophylactic thyroidectomy in patients with multiple endocrine neoplasia (MEN) type 2 offers the best chance for a normal life expectancy.

OBJECTIVE

To analyze the results of thyroidectomy performed during the first year of life in six patients with MEN 2A (codon 634) or MEN 2B (codon 918) syndrome.

DESIGN AND SETTING

A university hospital-based prospective study from 2001 to 2008.

SUBJECTS AND METHODS

Six family members affected either by MEN 2A (n=3) or MEN 2B (n=3) syndrome were identified through neonatal genetic screening.

RESULTS

Total thyroidectomy was performed at a median age of 0.8 year in the six patients, with central lymph node dissection in five. Bilateral millimetric medullary thyroid carcinoma (MTC) was found in all patients, with a unilateral lymph node micrometastasis in two of the three MEN 2B patients. Before thyroidectomy, MEN 2B patients had much higher basal serum calcitonin levels than those with MEN 2A and controls. After thyroidectomy, with a median follow-up of 3.3 years, the six patients had no evidence of persistent MTC.

CONCLUSION

Bilateral millimetric MTC may be present during the first year of life in these patients, with lymph node metastases also occurring in MEN 2B patients. These results support a total thyroidectomy at the age of about one year in MEN 2A (codon 634) children with an abnormal serum calcitonin level, and a total thyroidectomy with central neck dissection within the first weeks of life in MEN 2B patients.

Enhanced antimalarial activity of novel synthetic aculeatin derivatives

We report the design, synthesis, and in vitro evaluation of novel polyspirocyclic structures, inspired by the antimalarial natural products, the aculeatins. A divergent synthetic strategy was conceived for the practical supply and has allowed the discovery of two novel and more potent analogues active on the Plasmodium falciparum 3D7 strain. Moreover, these compounds proved to be potent against Toxoplasma gondii. A number of features that govern these inhibitions were identified.

In neuroblastic tumours, Schwann cells do not harbour the genetic alterations of neuroblasts but may nevertheless share the same clonal origin

Neuroblastic tumours are composed of variable proportions of neuroblasts and Schwann cells. Whether both components share a common neoplastic origin is highly debated and discrepant results have been reported about the presence of tumour-related genetic alterations in Schwann cells. We have used X-methylation analysis and array-CGH to investigate contiguous Schwannian and neuroblastic areas in tumours with a nodular pattern. A skewed X inactivation was observed in four out of five stromal components. Interestingly, in these four cases, the X-inactivation profiles of the neuroblastic components were identical to the matched stromal areas. However, whereas all neuroblastic areas displayed chromosomal imbalances, no alteration was found in any Schwann cell components. Similarly, no alteration was observed in a series of 19 tumours with a single stroma-rich component, which occasionally exhibited a skewed X-inactivation pattern (3/17 informative tumours). Altogether, this indicates that most stroma-rich tumours display a polyclonal proliferation and that Schwann cells do not derive from neuroblasts. However, in tumours with both stroma-rich and -poor components, our results suggest that cells from both areas share a common progenitor.

Leukocytes and the kidney contribute to interstitial inflammation in lupus nephritis

Interstitial leucocyte infiltration, a prominent feature of lupus nephritis, predicts deterioration of renal function. We used two models of lupus nephritis in mice, one with chronic spontaneous disease and the other with acute interferon-alpha (IFN alpha)-mediated disease. The latter is characterized by the virtual absence of interstitial infiltration. In vivo migration assays showed that splenic leukocytes from spontaneously nephritic mice tended to migrate into non-inflamed syngeneic kidneys. This was enhanced if the recipient kidneys were already inflamed. Kidneys from both chronically and acutely nephritic mice showed similar ability to recruit splenic leukocytes from chronically diseased mice. Leukocytes from acutely diseased mice, however, failed to migrate into chronically inflamed kidney. Compared with those with chronic nephritis, the kidneys of acute nephritic mice expressed less of the inflammatory chemokine CXCL13/BLC. Moreover, leukocytes from acute nephritic mice displayed impaired migration, in vitro, to T-cell chemokine attractants. This study links leukocyte infiltration to both kidney chemokine expression, and leukocyte chemotaxis to kidney-expressed chemokines.

Diastereodivergent strategies for the synthesis of homochiral aculeatins

We report concise and stereocontrolled syntheses of aculeatins (-)-A, (+)-B, (+)-D, and (+)-6-epi-D. Diastereodivergent 1,3-inductions in Mukaiyama aldol coupling contribute to reduce steps and to increase flexibility with reactants having sterically restricted proximal substituents (i.e., CH2), involving either a good anti or a moderate syn 1,3-induction, depending on the nature of protecting group (P). In addition, the 3,5-syn-diol-ketone resulting from concomitant deprotection of the beta-alkoxy (Tr = trityl) group proves to be remarkably stable whereas the 3,5-anti diastereoisomer cyclizes spontaneously to the corresponding tetrahydropyran hemiketal, thus enabling a useful and facile separation. The second part of our study is devoted to improving the yield and the diastereoselectivity of the final phenolic oxidation reaction leading to aculeatins.

A transient microenvironment loaded mainly with macrophages in the early developing human pancreas

We have previously shown that the human developing pancreas, as a tissue under construction and remodeling, is composed of epithelial ducts and differentiated endocrine cells surrounded by mesenchyme. The physiologic importance of resident tissue leukocytes, expected to enter through the mesenchyme in remodeling functions, prompted us to investigate human developing pancreases for the presence of leukocyte lineages and for expression of cytokines and receptors involved in their recruitment and differentiation. Immunohistochemistry studies were performed on 69 human, paraffin-embedded pancreases at 6-12 weeks of development (WD). Cytokines and receptor transcripts were monitored by reverse transcription (RT)-PCR, by immunohistochemistry when antibodies were available or by in situ hybridization (ISH). We show that numerous cells expressing CD45RA, HLADR and CD68 antigens are cellular components of the mesenchyme of all the pancreases at 6-12 WD. So-called constitutive chemokines (SLC (CCL19), stromal-derived factor 1 (SDF1) (CXCL12)) and a macrophage-specific growth/survival factor, colony-stimulating factor 1 (CSF1), were detected in epithelial duct cells. Both epithelial and mesenchymal cells expressed chemokine receptors, suggesting a role in leukocyte recruitment and possibly in early pancreatic development. In conclusion, we demonstrated the presence of CD45RA resident leukocyte-derived lineages, mostly macrophages, in the early human pancreatic mesenchyme. These cells may have migrated in the tissue through the vascular system, attracted by constitutively expressed chemokines, and locally surviving through CSF1 signaling. The role of macrophages in epithelium/mesenchyme interaction-mediated pancreatic development remains to be demonstrated.

[Peripheral neuroblastic tumors: anatomo pathological classification]

Peripheral Neuroblastic Tumors are classified according to the recommendations of the INPC into four categories and their subtypes: 1/Neuroblastoma stroma poor, undifferentiated, poorly differentiated, and differentiating, 2/ganglioneuroblastoma stroma composite, nodular, 3/ganglioneuroblastoma stroma composite, intermixed and 4/ganglioneuromas stroma dominant, maturing and mature. The classification is based on age and morphologic features of PNT, including the differentiation grade of the neuroblasts and the mitosis-karyorrhexis index. Histopathological classification has prognostic impact in predicting overall and event-free survival allowing the categorisation of PNT into two groups: favorable subset and unfavorable subset.

Cytokines, chemokine receptors, and homing molecule distribution in the rectum and stomach of pediatric patients with ulcerative colitis

BACKGROUND

Cytokines appear to play a significant role in the pathogenesis of inflammatory bowel disease (IBD) with a predominant Th2 pattern in colonic mucosa of patients with ulcerative colitis (UC). Chemokines and their receptors also regulate the migration of Th1 or Th2 lymphocytes to inflammatory tissues during the immune response. Although adult UC is usually confined to the colon, pediatric UC not uncommonly affects the stomach.

AIMS

The aim of this study was to compare expression of cytokines, chemokine receptors, and homing molecules in the rectal and the histologically characterized gastric mucosa of pediatric patients with UC. SUBJECTS Sixteen patients (11 girls and 5 boys; median age, 9 years) having all the features of UC were included in the study.

METHODS

Rectal and gastric mucosa obtained from UC cases were immunostained with antibodies against L-selectin, beta 7 integrin, CXCR3, CCR3, and CCR5. IL-4 and IL-12 p40 transcript expression was studied by in situ hybridization.

RESULTS

Chronic gastritis was found in 93.7% of cases and Helicobacter pylori (Hp) was found in 2 (13.3%) cases. In the rectal and gastric mucosa, CXCR3 was found in perivascular lymphocytes and CCR5 in a subset of CXCR3+ cells in the lamina propria. CCR3+ lymphocytes and IL-4-positive cells were always found, but there was no evidence of IL-12 production. Most of the lymphocytes infiltrating the gastric mucosa expressed beta 7 but not CD62L. In contrast, beta 7-positive cells were randomly dispersed in the rectal lamina propria, and the fraction of CD3+beta 7+ was low.

CONCLUSIONS

The authors conclude that gastritis is common in pediatric UC. The presence of CCR3+ lymphocytes, IL-4 transcript expression, without IL-12 p40 production in the stomach and in the rectum suggests a Th2 immune response. The presence of CCR3+, CD62L- activated Th2 cells may suggest that these gastric cells are recruited from colorectal primary lesions.

Laparoscopic adrenal surgery for neuroblastomas in children

PURPOSE

The role of laparoscopy in children with neuroblastomas has not been fully defined. The laparoscopic approach to the adrenal gland is already largely used in adults and a few cases have been reported in children. We report the experience of a single surgical team center with laparoscopic adrenal surgery for neuroblastomas in children.

MATERIALS AND METHODS

Between September 2000 and October 2002 laparoscopic adrenalectomy for neuroblastoma was performed in 9 patients (6 girls and 3 boys) with a mean age of 38 months (range 2 months to 9 years). Two tumors were detected prenatally and 7 postnatally. Preoperative diagnosis was neuroblastoma stage I in 4 cases and stage IV in 3 cases, and nondetermined suprarenal calcified masses in 2 cases. A 4 or 5-trocar transperitoneal approach was used in all cases. The adrenal tumors were completely excised, placed into a plastic bag and removed through the umbilical trocar site.

RESULTS

All of the adrenal tumors were well encapsulated and completely excised. One of the 9 procedures was converted to open surgery because of adhesions to renal vessels. In 1 case a second hepatic localization was removed simultaneously, and in 3 cases 1 or more lymph nodes were resected. Average operative time was 85 minutes (range 45 to 170). There were no deaths. There were no postoperative complications, except 1 port site infection that was treated locally. Blood transfusion was not required. Average hospital stay was 4.5 days (range 2 to 10). Histological analysis of the 9 specimens (maximum length 6 cm) confirmed the diagnosis of neuroblastoma. N-myc status was studied in 8 of the 9 resected neuroblastomas and was amplified in 2 cases (both stage IV with preoperative biopsy). Average postoperative followup was 15 months (range 1 to 25). There was no local recurrence or metastasis, except in the case that required conversion to open surgery (local recurrence 7 months later).

CONCLUSIONS

Laparoscopic adrenalectomy for neuroblastoma is safe and feasible in children, with good results. Experience with advanced laparoscopic surgery is required to achieve this result in optimal oncological conditions. Our short-term results must be reevaluated at long term, and further studies are needed to compare laparoscopy to open surgical techniques.

Card15 gene overexpression in mononuclear and epithelial cells of the inflamed Crohn's disease colon

BACKGROUND

Crohn's disease is one of the principal human chronic inflammatory bowel diseases. Although its aetiology is still unknown, its complex pathogenesis has environmental, immunological, and genetic determinants. CARD15 is the first susceptibility gene implicated in the predisposition to Crohn's disease and is known to be expressed only in monocytes. However, its expression in situ has not yet been studied.

AIMS

To analyse the tissue distribution of CARD15 and identify cells producing CARD15 in samples of colon from patients with Crohn's disease and control subjects.

PATIENTS AND METHODS

We analysed CARD15 gene expression in surgical specimens of colon from eight children with Crohn's disease and nine controls by immunohistochemistry, in situ hybridisation, and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

We showed that CARD15 was present only in the cytoplasm of macrophages in the normal colon. Increased CARD15 expression was detected in Crohn's disease lesions. There were more CARD15 positive cells in Crohn's disease lesions than in uninvolved areas. Both intestinal epithelial cells, macrophages, and their derivatives overproduced CARD15 in Crohn's disease. To further assess CARD15 expression by intestinal epithelial cells, we performed RT-PCR on freshly isolated intestinal epithelial cells, and showed that these cells isolated from Crohn's disease samples contained more CARD15 mRNA than intestinal epithelial cells from controls.

CONCLUSIONS

We have demonstrated that colonic involvement in active Crohn's disease is associated with increased CARD15 gene expression in both macrophages and intestinal epithelial cells. Therefore, this deregulation can affect the host-environment interaction and thus contribute to the pathogenesis of this disease.

Esophageal ligature in experimental gastroschisis

BACKGROUND/PURPOSE

Recently, the authors have shown that in human fetuses suffering from gastroschisis, there is an amniotic fluid inflammatory response and that amniotic fluid exchange designed to disrupt the inflammatory loop seems to have a favorable impact on outcome. The authors, therefore, designed in the fetal sheep a model of gastroschisis in which amnioinfusion significantly improved the deleterious process. They hypothesized that regurgitation and presence of digestive enzyme in the amniotic fluid triggers and maintains the process of inflammation.

METHODS

To test this hypothesis, the authors used their model of gastroschisis in the fetal lamb combined with esophageal ligation and compared it with gastroschisis with or without amnioinfusion.

RESULTS

Of 34 fetuses operated on at midgestation (days 70 through 80), 11 died in utero or were stillborn, 8 had gastroschisis and amnioinfusion, 8 had gastroschisis and no amnioinfusion, and 7 had gastroschisis and esophageal ligation. There were 9 control fetuses. Fetuses were killed at day 145 by cesarean section. Extraabdominal bowels with fibrous peel were processed for histologic examination. Thickness of bowel muscularis (micrometers) was 82.7 +/- 19 for controls, 159 +/- 56 for the nonamnioinfused fetuses, 126 +/- 21 for the amnioinfused fetuses (P =.001), and 240 +/- 225.8 for fetuses with esophageal ligature combined with gastroschisis. The same results were obtained for thickness of serous fibrosis and plasma cell infiltration. Assay of amniotic fluid ferritin, lipase, and protein showed that only amnioinfusion lowered ferritin and protein to levels similar to those of controls, thus, illustrating its preventive effect on inflammation and that esophageal ligature did not prevent digestive enzyme presence in the amniotic fluid.

CONCLUSION

In this model of gastroschisis in the fetal sheep, ligature of the esophagus, which was supposed to protect the extruded bowel by preventing oral regurgitation of digestive enzymes and by creating a relative hydramnios, did not improve the inflammatory and deleterious process, which is best prevented by amnioinfusion.

The IGF system in neuroblastoma xenografts: focus on IGF-binding protein-6

With a view to investigating the implication of IGF-binding protein-6 (IGFBP-6) in the growth of neuroblastomas, nude mice were injected with IGFBP-6-expressing or control IGR-N-91 human neuroblastoma cells and the resulting xenografts examined. Expression of IGFBP-3, IGFBP-4 and type 1 and type 2 IGF receptor messengers was similar in control tumours and equal-sized IGFBP-6-expressing tumours that had developed. IGF-II was more strongly expressed in control tumours, and IGFBP-6-expressing tumours contained less IGFBP-2 than controls. In both populations, there was a significant positive correlation between IGF-II and IGFBP-2 expression. In small IGFBP-6-expressing xenografts where tumour development had apparently been arrested, haematoxylin--eosin and TUNEL staining revealed numerous apoptotic cells. In situ hybridization indicated homogeneous distribution of the IGFBP-6 signal in test tumours. In cell culture, IGFBP-6-expressing cells expressed similar amounts of IGFBP-2, IGF-II and N-myc mRNAs as control cells; but media conditioned by IGFBP-6-expressing cells contained less intact IGFBP-2 protein, with no increase in its proteolytic fragment. In media treated with plasminogen, in which IGFBP-2 was proteolysed, IGFBP-6 was increased. With its especially strong affinity for IGF-II and its resistance to proteolysis, IGFBP-6 would act by sequestering IGF-II, hence inhibiting its mitogenic and anti-apoptotic effects. In excess, IGFBP-6 would displace IGF-II from IGFBP-2 whose potentiation of IGF-II action would cease and whose susceptibility to degradation would be increased. This study therefore shows that IGFBP-6 plays a role in neuroblastoma cell growth in vivo and in vitro and that stable overexpression of IGFBP-6 leads to alteration of the initial balance between the IGFBPs.

Investigation of osteocalcin, osteonectin, and dentin sialophosphoprotein in developing human teeth

Biochemical investigations in rodents have shown that numerous mineralized matrix proteins share expression in bone, dentin, and cementum. Little information is available regarding the expression pattern of these proteins in human tissues, particularly during tooth formation. The aim of this study was to identify the expression pattern of the two major noncollagenous proteins of bone and dentin, osteocalcin (OC) and osteonectin (ON), in comparison to the dentin-specific protein, dentin sialophosphoprotein (DSPP). Mandibles from fetuses (5-26 weeks), neonate autopsies, forming teeth from 10-12-year-old patients, third molars extracted for orthodontic reasons, and bone tumors were collected with approval from the National Ethics Committee. Human OC, ON, and DSPP mRNAs were detected by reverse transcription-polymerase chain reaction (RT-PCR) in fetal mandibles (5-11 weeks) and in primary cell cultures of dental pulp. In addition, OC, ON, and DSPP proteins were localized in forming human mineralized tissues using immunohistochemistry. In vivo, DSPP expression was associated with tooth terminal epithelial-mesenchymal interaction events, amelogenesis and dentinogenesis. Transient DSPP expression was seen in the presecretory ameloblasts with continuous expression in the odontoblasts. In contrast, both osteoblasts and odontoblasts showed a temporal gap between OC and ON expression in early development. ON was expressed in the initial stages of cytodifferentiation, whereas OC was expressed only during the later stages, especially in the teeth. At the maturation stage of enamel formation, both proteins were detected in odontoblasts and their processes within the extracellular matrix. In contrast to bone, OC was not localized extracellularly within the collagen-rich dentin matrix (predentin or intertubular dentin), but was found in the mature enamel. ON was present mostly in the nonmineralized predentin. These results demonstrate for the first time that both OC and ON are produced by human odontoblasts and determine the expression pattern of DSPP in human teeth, and suggest that OC and ON move inside the canalicule via odontoblast cell processes becoming localized to specific extracellular compartments during dentin and enamel formation. These distinct extracellular patterns may be related to the nature of DSPP, OC, and ON interactions with other matrix-specific macromolecules (i.e., amelogenin, dentin matrix protein-1) and/or to the polarized organization of odontoblast secretion as compared with osteoblasts.

Chimaeric anti-CD20 monoclonal antibody (rituximab) in post-transplant B-lymphoproliferative disorder following stem cell transplantation in children

Post-transplant lymphoproliferative disorder (PTLD) after haemopoietic stem cell transplantation is a serious complication that occurs in 8-22% of patients with high-risk factors. We retrospectively investigated tolerance and efficacy of humanized anti-CD20 monoclonal antibody (rituximab) as first-line treatment in 12 children with B-cell PTLD. At diagnosis, eight patients had tumoral involvement. The other four patients had fever, associated with raised Epstein-Barr virus (EBV) viral load and monoclonal gammopathy. Rituximab was given at the dose of 375 mg/m2 once a week by intravenous infusion (1-9 infusions). Only 1/48 infusions was associated with a grade 2 clinical adverse event. Eight out of 12 (66%) patients responded to the treatment and were in complete remission. All patients without tumoral involvement responded to the treatment. A rapid decrease in fever within 1 week was observed in all responders. Non-responders did not show any clinical response during the first week. Tumoral involvement and immunodepression seemed to be more marked in non-responders. Rituximab was an effective and well-tolerated treatment of B-cell PTLD. Early treatment before tumoral involvement seemed to be the most effective approach. Lack of rapid response should lead to intensification of PTLD treatment. Pre-emptive treatment should be considered and evaluated in further longitudinal multicentre studies.