Laparoscopic enucleation of pancreatic neoplasm.

BACKGROUND: Enucleation is an alternative procedure for treating benign and borderline neoplasms of the pancreas, which preserves healthy parenchyma and pancreatic function. This study aimed to evaluate the postoperative and long-term results after laparoscopic enucleation. METHODS: Data collected prospectively from 23 consecutive patients who underwent laparoscopic pancreatic enucleation were analyzed. RESULTS: Laparoscopic enucleation was achieved successfully for 21 patients (91.3%). One death (4%) occurred. A postoperative pancreatic fistula was observed in three cases (13%), and was clinically significant in one case (4%). Enucleation was performed for endocrine neoplasm in 15 patients (65%) and for cystic neoplasm in eight patients (35%). All the patients had benign tumors at the final histopathologic diagnosis. During a median follow-up period of 53 months, no patient experienced tumor recurrence or new-onset exocrine or endocrine insufficiency. CONCLUSION: Laparoscopic enucleation is a safe and effective procedure for the radical treatment of benign and borderline pancreatic tumors. The laparoscopic approach seems to be associated with a decrease in operative time, hospital stay, and pancreatic fistula after enucleation. Laparoscopy should become the standard approach in the future for enucleation of presumed benign lesions.

T4 colorectal cancer: is laparoscopic resection contraindicated?

AIM: T4 colorectal cancer remains a contraindication for laparoscopy. It is argued that the risk of incomplete resection could be higher than in open surgery. Furthermore, difficulty in dissection could lead to a very high rate of conversion. There is little information on this. The study aimed at assessing feasibility and operative and oncologic results of laparoscopic resection for T4 colorectal cancer. METHOD: Between 2006 and 2009, 39 patients with colorectal cancer with suspected involvement of another organ (T4) on computed tomography scanning and/or magnetic resonance imaging were included. The cancers were in the right colon (n = 18), left colon (n =9) and rectum (n = 12). The distribution of possible organ involvement was abdominal or pelvic side-wall (n = 21), urinary bladder (n = 4), small bowel or colon (n = 6), vagina and ovary (n = 3), prostate or seminal vesicles (n = 3) and duodenum (n = 2). RESULTS: The overall conversion rate was 18%. Postoperative mortality and morbidity were 2.5 and 33%, respectively. Clinical anastomotic leakage rate was 15% (n = 6). Abdominal reoperation was required in three (7%) patients. Pathological invasion to other organs (pT4) was confirmed in 30 (77%) patients. The R1 resection rate was 13% (4 of 30). After a median follow up of 19 months (range 1.5-45 months), the overall survival and disease-free survival rates were 97 and 89%, respectively. CONCLUSION: This study suggests that laparoscopic surgery is feasible for colorectal T4 cancer resection. Laparoscopy cannot therefore be considered an absolute contraindication for T4 colorectal cancer.

Medicago truncatula ENOD11: a novel RPRP-encoding early nodulin gene expressed during mycorrhization in arbuscule-containing cells.

Leguminous plants establish endosymbiotic associations with both rhizobia (nitrogen fixation) and arbuscular mycorrhizal fungi (phosphate uptake). These associations involve controlled entry of the soil microsymbiont into the root and the coordinated differentiation of the respective partners to generate the appropriate exchange interfaces. As part of a study to evaluate analogies at the molecular level between these two plant-microbe interactions, we focused on genes from Medicago truncatula encoding putative cell wall repetitive proline-rich proteins (RPRPs) expressed during the early stages of root nodulation. Here we report that a novel RPRP-encoding gene, MtENOD11, is transcribed during preinfection and infection stages of nodulation in root and nodule tissues. By means of reverse transcription-polymerase chain reaction and a promoter-reporter gene strategy, we demonstrate that this gene is also expressed during root colonization by endomycorrhizal fungi in inner cortical cells containing recently formed arbuscules. In contrast, no activation of MtENOD11 is observed during root colonization by a nonsymbiotic, biotrophic Rhizoctonia fungal species. Analysis of transgenic Medicago spp. plants expressing pMtENOD11-gusA also revealed that this gene is transcribed in a variety of nonsymbiotic specialized cell types in the root, shoot, and developing seed, either sharing high secretion/metabolite exchange activity or subject to regulated modifications in cell shape. The potential role of early nodulins with atypical RPRP structures such as ENOD11 and ENOD12 in symbiotic and nonsymbiotic cellular contexts is discussed.

Interaction of M(3+) Lanthanide Cations with Amide, Pyridine, and Phosphoryl O=PPh(3) Ligands: A Quantum Mechanics Study.

We report an ab initio quantum mechanical study on the interaction of M(n)()(+) cations (M(n)()(+) = La(3+), Eu(3+), Yb(3+), Sr(2+), and Na(+)) with model ligands L for lanthanide or actinide cations: several substituted amides, pyridines, and the phosphoryl-containing OPPh(3) ligand. The interaction energies DeltaE follow trends expected from the cation hardness and ligand basicity or softness in the amide series (primary < secondary-cis < secondary-trans < tertiary) as well as in the pyridine series (para-NO(2) < H < Me < NMe(2)). Among all ligands studied, OPPh(3) is clearly the best, while the (best) tertiary amide binds lanthanides slightly less than the (best) pyridine-NMe(2) ligand. In the lanthanide 1:1 complexes, the energy differences DeltaDeltaE as a function of M(3+) (about 40 kcal/mol for all ligands) are less than DeltaDeltaE in the pyridine series (up to about 90 kcal/mol) where marked polarization effects are found. The conclusions are validated by a number of methodological investigations. In addition to optimal binding features, we also investigate the directionality of ion coordination to the ligands and the effect of counterions and stoichiometry on the structural, electronic and energetic features of the complexes. The results are discussed in the context of modeling complexes of lanthanide and actinide cations and compared to those obtained with analogous Na(+) and Sr(2+) complexes.

MtENOD16 and 20 are members of a family of phytocyanin-related early nodulins.

We have identified two single-copy genes from the model legume. Medicago truncatula (MtENOD16 and 20) whose expression can be correlated with early stages of root nodulation and whose predicted coding sequences are partially homologous to both pea/vetch ENOD5 and soybean N315/ENOD55. Database searching and sequence alignment have defined the encoded early nodulins as a distinct sub-family of phytocyanin-related proteins, although the absence of key ligands implies that they are unlikely to bind copper. Molecular modelling based on known phytocyanin structure has been used to predict the 3-dimensional conformation of the principle globular domain of MtENOD16/20. Additional structural features common to both early nodulin and phytocyanin precursors include an N-terminal transit peptide, a highly variable (hydroxy)proline-rich sequence which probably undergoes extensive post-translational modification, and a hydrophobic C-terminal tail.

Rhizobium meliloti Nod factors elicit cell-specific transcription of the ENOD12 gene in transgenic alfalfa.

Extracellular lipo-oligosaccharides of Rhizobium, known as Nod factors, play a key role in the molecular signal exchange which leads to the specific nitrogen-fixing symbiotic association between the soil microbe and its host legume. The biological activity of Nod factors and their perception by the host plant during the earliest stages of the Rhizobium/legume interaction have been studied using transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the beta-glucuronidase (GUS) reporter gene. Histochemical staining has shown that GUS accumulates specifically in the differentiating root epidermis, prior to and during root hair emergence, within 2-3 h following the addition of purified Rhizobium meliloti Nod factors. This precocious transcriptional activation of the MtENOD12 gene, reminiscent of that observed after inoculation with intact Rhizobium, implies that the Nod factor signal can be perceived at a developmental stage preceding root hair formation. GUS activity can be detected following treatment with a wide range of R. meliloti Nod factor concentrations down to 10(-13) M, and furthermore, this rapid response to the bacterial elicitor appears to be non-systemic. Significantly, MtENOD12-GUS expression is not observed after inoculation with a R. meliloti nodH mutant which synthesizes exclusively non-sulphated Nod factors. Indeed purified Nod factors which lack the sulphate substituent are approximately 1000-fold less active than their sulphated counterparts. Thus, the triggering of ENOD12 transcription in the alfalfa root epidermis is a rapid molecular response which is subject to the same host-specificity determinant (Nod factor sulphation) that governs the interaction between alfalfa and its bacterial symbiont.

Rhizobium meliloti elicits transient expression of the early nodulin gene ENOD12 in the differentiating root epidermis of transgenic alfalfa.

To study the molecular responses of the host legume during early stages of the symbiotic interaction with Rhizobium, we have cloned and characterized the infection-related early nodulin gene MtENOD12 from Medicago truncatula. In situ hybridization experiments have shown that, within the indeterminate Medicago nodule, transcription of the MtENOD12 gene begins in cell layers of meristematic origin that lie ahead of the infection zone, suggesting that these cells are undergoing preparation for bacterial infection. Histochemical analysis of transgenic alfalfa plants that express an MtENOD12 promoter-beta-glucuronidase gene fusion has confirmed this result and further revealed that MtENOD12 gene transcription occurs as early as 3 to 6 hr following inoculation with R. meliloti in a zone of differentiating root epidermal cells which lies close to the growing root tip. It is likely that this transient, nodulation (nod) gene-dependent activation of the ENOD12 gene also corresponds to the preparation of the plant for bacterial infection. We anticipate that this extremely precocious response to Rhizobium will provide a valuable molecular marker for studying early signal exchange between the two symbiotic organisms.

Synchronous expression of leghaemoglobin genes in Medicago truncatula during nitrogen-fixing root nodule development and response to exogenously supplied nitrate.

Two leghaemoglobin genes from the diploid, autogamous Medicago truncatula (Mtlb1 and Mtlb2) have been cloned and their nucleotide sequences determined. The deduced amino acid sequences encoded by these two genes differ significantly (18%), confirming that they belong to different sub-groups of Medicago leghaemoglobin genes. RNAse protection experiments have been used to show that both genes are transcriptionally active, and are expressed specifically in the nitrogen-fixing root nodule of M. truncatula. Whilst Mtlb1 mRNA is present at approximatively 3-fold higher steady-state levels than Mtlb2 mRNA, the transcription of both genes is triggered concomitantly during nodule development (5 days after inoculation with Rhizobium meliloti), and the ratio of the steady-state levels of the two mRNA species remains constant throughout nodule maturation. When the growth medium of nodulated M. truncatula is supplemented with 5 mM KNO3 over a period of 2-3 days there is a progressive drop in specific nitrogen fixation activity to only 20-25% of the original level. This is accompanied with a parallel and synchronous reduction in the quantities of mRNA corresponding to both Mtlb1 and Mtlb2. By contrast, the expression of the nodule parenchyma-specific gene ENOD2 is not significantly modified following nitrate treatment, clearly demonstrating differences in tissue-specific gene regulation in response to combined nitrogen.

Cascade regulation of nif gene expression in Rhizobium meliloti.

We report the discovery of two genes from Rhizobium meliloti, fixL and fixJ, which are positive regulators of symbiotic expression of diverse nitrogen fixation (nif and fix) genes. nif gene regulation is shown to consist of a cascade: the fixLJ genes activate nifA, which in turn activates nifHDK and fixABCX. Like nifA, fixN can be induced in free-living microaerobic cultures of R. meliloti, indicating a major physiological role for oxygen in nif and fix gene regulation. Microaerobic expression of fixN and nifA depends on fixL and fixJ. The FixL and FixJ proteins belong to a family of two-component regulatory systems widely spread among prokaryotes and responsive to the cell environment. We propose that FixL, which has features of a transmembrane protein, senses an environmental signal and transduces it to FixJ, a transcriptional activator of nif and fix genes.

Quantitation of human serum apolipoprotein B by enzyme immunoassay in excess antigen.

A solid phase enzyme-linked immunoassay based on the 'sandwich' principle was developed for quantitative measurement of apolipoprotein B (Apo B) in human normal or hyperlipoproteinemic sera. The solid phase (polypropylene multi-finned sticks) coated with an excess of sheep anti-Apo B immunoglobulins was incubated with antigen (standards and unknown specimens) and affinity-purified anti-Apo B antibodies conjugated with horseradish peroxidase. In this principle, antigen and conjugate were in excess and fixed amount respectively. A part of antigen was fixed on multi-finned sticks, bound or not to conjugate. Unbound materials were removed by washing. Solid phases were next incubated with the enzyme substrate solution to develop a color which is inversely related to the amount of Apo B. The best technical conditions for the assay were determined. The method was characterized according to precision, sensitivity and accuracy. It yielded values that compared favorably with those obtained by another enzyme-linked immunoassay and by electroimmunoassay.

Saccharomyces cerevisiae ARS on a plasmid from Staphylococcus aureus.

Staphylococcus aureus plasmid pC194 carries three sequences closely related to a consensus sequence defined previously by analysis of different genetic elements which replicate autonomously in yeast Saccharomyces cerevisiae. Two of these enable the plasmid to replicate in yeast, the third does not. A new consensus sequence A/T T T T A T R T T T, 1 bp shorter than the previous one, can be deduced from our results. Replacement of the T with G at the position 9 of the sequence abolishes its activity. The presence of the two active sequences on pC194 genome can be explained by the A + T-rich base composition of the plasmid.

Synthesis of a 125I-labelled derivative of the antibiotic griseofulvin.

A derivative of griseofulvin has been synthesised, in which the 2'-O-methyl group is replaced by a 2'-(2-iodoethoxy), 125I-labelled group. This derivative is at least as potent as griseofulvin itself, when assayed for inhibition of growth on the Myxomycete Physarum polycephalum.