Frequency and severity of ileal adenomas in familial adenomatous polyposis after colectomy

BACKGROUND AND STUDY AIMS

The high cumulative risk of colorectal cancer in patients with familial adenomatous polyposis (FAP) justifies prophylactic colectomy with either ileorectal (IRA) or ileal-pouch-anal anastomosis (IPAA). Our aim was to evaluate retrospectively the frequency of and time interval to adenoma development in the ileal mucosa of patients with both types of surgery.

PATIENTS AND METHODS

Retrospective study of 44 FAP patients with IRA (n = 21) and IPAA (n = 23). All patients were followed with a standardized procedure including chromoscopy and biopsies of visible polyps. In patients with IRA, specific attention was paid to the ileal mucosa above the anastomosis.

RESULTS

In the IPAA group, 18/23 patients (78 %) presented with visible polyps [histology: 16 (70 %) had adenoma with low-grade dysplasia; 1 (4 %) had adenoma with high-grade dysplasia; 1 had normal mucosa]. The mean interval between colectomy and the diagnosis of adenoma was 4.7 +/- 3.3 years. In the IRA group, 16/21 patients (77 %) presented visible polyps in the ileal mucosa [adenoma with low-grade dysplasia in 8 patients (38 %), with high-grade dysplasia in 2 (10 %), and lymphoid nodular hyperplasia in 6]. The mean interval between colectomy and adenoma diagnosis was significantly shorter in the IPAA than in the IRA group (4.76 +/- 3.3 vs. 16.4 +/- 8.5 years, P< 0.0001).

CONCLUSION

Our results show a high frequency of adenomas in the ileal mucosa of patients with IPAA and IRA (74 % and 48 % respectively), with evolution into high-grade dysplasia in 6.7 % of cases.

CD99 isoforms dictate opposite functions in tumour malignancy and metastases by activating or repressing c-Src kinase activity

CD99 gene encodes two distinct proteins, produced by alternative splicing of CD99 gene transcript. Full-length CD99 isoform (CD99wt) is formed by an extracellular domain, followed by a transmembrane domain and a 36 amino-acid intracytoplasmic domain, which is partially deleted in the truncated, short form (CD99sh). A differential expression of these two CD99 molecules can lead to distinct functional outcomes in lymphocytes. To investigate the functional effects of CD99 molecules on malignancy, forced overexpression of the two CD99 isoforms was induced in osteosarcoma and prostate cancer cells. The two isoforms exhibited opposite functions: the major form dramatically inhibits anchorage-independent growth, anoikis resistance, migration and metastasis, whereas the CD99sh remarkably favours the phenomena. A mechanistic analysis of CD99-transfected osteosarcoma cells points to involvement of c-Src family kinase activity in regulating CD99 functions in malignancy. Ser168 residue of CD99 plays a pivotal role in the reversion of the malignant phenotype. Our findings highlight the involvement of CD99 in crucial processes of cancer malignancy, serving as a curtain raiser for this, so far neglected molecule. In addition, a dualistic role for the two CD99 isoforms was shown in agreement with what was observed for other cell adhesion molecules.

Spontaneous hypoglycaemia in the presence of both anti-insulin antibody and anti-insulin receptor antibody

Beside insulinoma, alternative causes of hyperinsulinaemic hypoglycaemia include the rare autoimmune syndrome related to spontaneous autoantibodies either to insulin or to insulin receptor. We describe a case of hypoglycaemia with high insulinemia in which insulinoma could not be evidenced. Surprisingly, we found in the patient's serum both insulin autoantibodies and insulin receptor autoantibodies. Available data eventually supported the predominant role of insulin autoantibodies rather than insulin receptor autoantibodies in the mechanism of hypoglycaemia of this patient. Insulin antibodies were present in high titre. Most of the insulin in serum was bound to the insulin antibodies and free insulin was slightly increased. HLA typing displayed DR4 haplotype, known to be strongly linked to the insulin autoimmune syndrome. The patient's serum was able to inhibit insulin binding to its receptor in a cultured cell line overexpressing insulin receptors both in experiments with native serum and with serum depleted from insulin antibodies. However, we could not demonstrate that the insulin receptor antibodies had insulin mimicking effect. We have no obvious explanation for the presence of these two antibodies in the same patient. Possible hypotheses might involve an idiotype-anti-idiotype mechanism or a poly-autoimmune disease.

Phenotypic and molecular evaluation of a recurrent selection program for a polygenic resistance to Phytophthora capsici in pepper

'Criollo de Morelos 334' (CM334) is one of the most promising sources of resistance to Phytophthora capsici in pepper. This Mexican accession is distantly related to bell pepper and its resistance displays a complex inheritance. The QTLs involved in resistance to P. capsici were previously mapped. In order to transfer the resistance factors from CM334 into a bell pepper genetic background, a modified, recurrent breeding scheme was initiated. The breeding population was divided into three sub-populations which were screened by distinct phenotypic tests of increasing severity. The plants from the first sub-population were screened with low-severity tests and backcrossed to the susceptible bell pepper; the plants from the second and third sub-populations were screened by more severe resistance tests and crossed with the plants from the first and second sub-populations, respectively. In this study, the phenotypic data for the three sub-populations during five screening/intermating cycles were analysed. In parallel, the changes in allelic frequencies at molecular markers linked to the resistance QTLs were reported. The resistance phenotype and allelic frequencies strongly depended on the sub-population and screening severity. Regarding allelic frequency changes across the selection cycles, a loss of resistant QTL alleles was observed in the first sub-population, particularly for the low-effect QTLs, whereas a better conservation of the resistant QTL alleles was observed in the two other sub-populations. The same trend was observed in the phenotypic data with an increasing resistance level from the first to the third sub-populations. The changes in the allelic frequencies of loci not linked to resistance QTLs and for horticultural traits across the breeding process indicated that the recovery of the recipient parent genome was not significantly affected by the selection for resistance.

Tolerance and efficacy of argon plasma coagulation for controlling bleeding in patients with typical and atypical manifestations of watermelon stomach

BACKGROUND AND STUDY AIMS

Watermelon stomach is a well-known cause of gastrointestinal bleeding and anemia. This study investigated the efficacy of and patient tolerance for argon plasma coagulation (APC) in this condition.

PATIENTS AND METHODS

The reports of 21 patients with watermelon stomach who were treated using APC from February 1998 to August 2001 were reviewed. The efficacy of APC was evaluated on the basis of the patients' symptoms, transfusion requirements, and hemoglobin levels.

RESULTS

Fifty-nine APC sessions were carried out (mean 2.81 sessions per patient, range one to five). Depending on the bleeding outcome and lesion intensity, repeat treatments were carried out with a mean delay of 1.8 months (range 2 days - 6 months). The mean follow-up period after the last session was 14.9 months (1 - 60.6 months). All of the patients required repeated blood transfusions before APC, compared with only two patients after treatment. One of these two patients died of uncontrolled bleeding despite APC. The mean hemoglobin level was 80.9 g/l before treatment, compared with 103.2 g/l after treatment. Three patients had recurrent bleeding 4.4 - 31.7 months (mean 13.8 months) after the last session and required a further session of APC, which controlled bleeding in all cases. Complications encountered consisted of two cases of hematemesis and one of sepsis.

CONCLUSIONS

APC was effective in controlling bleeding due to watermelon stomach in the great majority of patients, with a low complication rate.

Evidence of melanin-concentrating hormone-containing neurons supplying both cortical and neuroendocrine projections

In the rat, melanin-concentrating hormone-containing projections are detected in the median eminence and in the neural lobe of the pituitary. After vascular injections of the retrograde tracers fluorogold or fastblue, melanin-concentrating hormone neurons are retrogradely labeled in the rostromedial zona incerta and adjacent perifornical region. These neurons may be the source of the melanin-concentrating hormone projections toward the median eminence and posterior pituitary, and may release their secretory products into the bloodstream. After fastblue injections in the cerebral cortex and vascular fluorogold injections, some melaninconcentrating hormone neurons contain both tracers, indicating that they send collaterals in the cerebral cortex and in the median eminence/posterior pituitary. No such collaterals have been described for the classical neuroendocrine systems. The melanin-concentrating hormone system is thought to play a role in arousal in correlation with specific goal oriented behaviors such as feeding or reproduction. Some MCH neurons may be involved in such functions by modulating directly cortical activity as well as being neuroendocrine.

Neuroendocrine-immune surveillance of osteosarcoma: emerging hypothesis

Osteosarcoma is a bone-forming cancer predominantly found in children and adolescents more often than in adults. Osteosarcoma of the gnathic apparatus is relatively rare in the young population, and this condition becomes a concern of clinical dentists for predominantly the middle-aged and aging patient groups. Osteosarcomas are invaded by lymphocytes, which exhibit signs of activation. The immune processes that are engaged within the malignant bone matrix involve the production of cytokines, which regulate the process of apoptotic programmed cell death. This paper discusses the mechanisms by which apoptosis of osteosarcoma cells is modulated by the neuroendocrine-immune system, and potential physiological implications.

Genes, isochores and bands in human chromosomes 21 and 22

The recently available DNA sequences from chromosomes 21 and 22 enabled us to define the relationships of different band types with isochores and with gene concentration and to compare these relationships with previous results. We showed that chromosomal bands appear as Giemsa or Reverse bands depending not on their absolute GC level, but on the composition GC level relative to those of adjacent contiguous bands. We also demonstrated that the GC-richest, and gene-richest H3+ bands are characterized by a lower DNA compaction compared with the GC-poorest, gene-poorest L1+ bands. Moreover, our results indicate that the human genome contains about 30,000 genes.

Non-expression of HLA-A*2901102 N is caused by a nucleotide exchange in the mRNA splicing site at the beginning of intron 4

We describe the identification of the novel human leukocyte antigen (HLA) blank allele A*2901102 N which was detected in an individual of mixed race. The serological HLA class I typing was A1; B7,44 whereas PCR-SSP indicated the presence of an additional A*29 allele. The pedigree analysis demonstrated that the new blank allele segregated with the haplotype A*29null B*07, inherited from the individual's Vietnamese father. A single G-->Tau transversion was detected at position 1 of intron 4, which is a highly conserved nucleotide position in vertebrate splice donor sites. Accordingly, it is very likely that this nucleotide exchange inhibits the splicing of intron 4, resulting in a premature stop codon further downstream. Despite this alteration, transcription into mRNA was demonstrated.

Distinct hematopoietic support by two human stromal cell lines

OBJECTIVE

The hematopoietic microenvironment is complex, and the role of myofibroblast in its function is crucial. In order to obtain a stable model reflecting this particular cell type, we have previously established human bone marrow cell lines from primary myofibroblastic Stro1(+) population (pStro1(+)). We placed HPV16 E6 and E7 expression under the control of different promoters. Here, we have characterized and studied the hematopoietic support for two cell lines corresponding to the promoters alpha-SM (alphaSM-56 line) and SV40 (SV40-56 line).

MATERIALS AND METHODS

The expression profile was analyzed at the RNA level by gene array and at the protein level by Western blot, flow cytometry, and ELISA. Hematopoietic support determined using colony-forming unit (CFU) and stroma-adherent colony-forming cell (SA-CFC) assays.

RESULTS

The phenotype of cell lines was not significantly modified compared with primary myofibroblastic cells. They secreted a broad spectrum of hematopoietic cytokines and nonspecific mediators. The two lines allowed the growth of hematopoietic precursors and had different support capabilities.

CONCLUSIONS

We have extensively characterized two novel human bone marrow stromal cell lines. They retained a myofibroblastic phenotype and have substantial but different hematopoietic support capabilities. These lines provided a basis for determining stromal factors involved in stem-cell regulation.

CD99 signals caspase-independent T cell death

Death signaling by Fas and TNF receptors plays a major role in the control of activated mature T cells. However, the nature of the death receptors, which may be used by the immune system to control T cells that have not acquired susceptibility to Fas ligand or TNF, is not established. In this study, we demonstrate that engagement of distinct epitopes on CD99 rapidly induces T cell death by a novel caspase-independent pathway. A new mAb to these CD99 epitopes, Ad20, induces programmed cell death of transformed T cells as determined by morphological changes, phosphatidylserine exposure on the cell surface, and uptake of propidium iodide. In general, ligation of CD99 induced kinetically faster and more profound death responses as compared with the impact of anti-Fas and TNF-related apoptosis-inducing ligand (TRAIL). Ad20-induced programmed cell death was observed with seven of eight T cell lines examined, and notably, only two of these were distinctly responsive to anti-Fas and TRAIL. CD99-mediated death signaling proceeded independently of functional CD3, CD4, CD45, and p56(lck), revealed distinctions from CD47-mediated T cell death responses, and was not influenced by interference with CD47 signaling. In contrast to the effect on transformed T cell lines, Ad20-induced death responses were not observed with normal peripheral T cells. Thus, our data suggest that CD99 is linked to a novel death pathway that may have biologic relevance in control of early T cells.