Inflammatory myoglandular colorectal polyps: a series of seven cases and review of literature.

INTRODUCTION: Inflammatory myoglandular polyp is an unusual but distinct, non-neoplastic type of colorectal polyp, commonly with a distal localization at the recto-sigmoidian level. It was first described in 1992 by Nakamura and his colleagues and it is considered to have few particular histological features. MATERIAL AND METHODS: We report a series of seven cases (two male and five female patients) of myoglandular polyps with different localization from 15 to 40 cm from anus. Only four out of seven cases presented with rectal bleeding, the others polyps we incidentally discovered. RESULTS: The polyps varied between 4 and 30 mm in the maximum diameter. Grossly, they had firm consistency and smooth reddish surface. Histological examination of the specimens revealed hyperplastic glands with occasional cystic dilatation, proliferation of smooth muscle with no regular distribution, a variable amount of granulation tissue (usually minimal) and no evidence of epithelial dysplasia. All the lesions were removed endoscopically without any complications. CONCLUSIONS: Inflammatory myoglandular polyps are distinct histopathological entities, with insufficiently investigated pathogenesis that can include local trauma, mucosal prolapse or ischemia. Being benign they can be removed endoscopically, surgical treatment being reserved in selected cases.

Does the RET variant G691S influence the features of sporadic medullary thyroid carcinoma?

OBJECTIVE: The RET (rearranged during transfection) proto-oncogene G691S variant is over-represented in the germline of patients with sporadic medullary thyroid carcinoma (sMTC) vs. normal controls but so far is not associated with any medical or pathological features of the tumour. The aim of our study was to assess the influence of this variant on the age of onset, clinical, biological and pathological features of sMTC. DESIGN AND PATIENTS: One hundred patients with histologically proven MTC, for whom the germline genetic analysis of RET was negative and medical records were available, were included in the study. RESULTS: Patients with the heterozygous GS variant or the homozygous SS variant (n = 36) were on average 8.0 years younger than patients with the wild-type GG variant (n = 64, mean age 43.9 vs. 51.9 years, P < 0.01). The former group did not differ from the wild-type group in terms of MTC size, prevalence of C-cell hyperplasia (CCH) or papillary thyroid carcinoma (PTC). However, the prevalence of an increased preoperative basal calcitonin (bCT) level (> 1000 pg/ml) was 2.75-fold higher in the patients with the GS or SS variant than in those with the wild-type variant (P < 0.001). The proportion of patients with lymph node metastases was also higher in the former group (P < 0.05). Multivariate analysis confirmed that the presence of the RET variant is independently associated with higher preoperative bCT values (P = 0.011). CONCLUSIONS: Our data demonstrate that the RET G691S variant could modulate the age of onset of sMTC as demonstrated previously for familial tumours. Moreover, this variant is an independent predictor of a higher basal calcitonin synthesis rate in patients with sMTC.

Endothelin-1 is synthesized and inhibits cyclic adenosine monophosphate- dependent anion secretion by an autocrine/paracrine mechanism in gallbladder epithelial cells.

Ion and fluid transport across the biliary epithelium contributes to bile secretion. Since endothelin (ET)-1 affects ion transport activities and is released by human gallbladder- derived biliary epithelial cells in primary culture, we examined the expression of ET peptides and ET receptors and the influence of ET-1 on ion transport in this epithelium ex vivo. In freshly isolated gallbladder epithelial cells, preproET-1, -2, and -3 mRNAs were detected by reverse transcription PCR and ET-1 isopeptide was identified by chromatography. The cells also displayed ET receptor mRNAs and high-affinity binding sites for ET-1, mostly of the ETB type. Electrogenic anion secretion across intact gallbladder mucosa was stimulated by forskolin, secretin, and exogenous ATP, as assessed by short-circuit current (Isc) increases in Ussing-type chambers. ET-1 inhibited forskolin- and secretin-induced changes in Isc, without affecting baseline Isc or ATP-induced changes. Accordingly, ET-1 significantly reduced the accumulation of intracellular cAMP elicited by forskolin and secretin in the epithelial cells, and this effect was abolished by pertussis toxin. This is the first evidence that ET-1 is synthesized and inhibits, via a Gi protein-coupled receptor, cAMP-dependent anion secretion in human gallbladder epithelium, indicating a role in the control of bile secretion by an autocrine/paracrine mechanism.

Simultaneous regression of Philadelphia chromosome and multiple nonrecurrent clonal chromosomal abnormalities with imatinib mesylate in a patient autografted 22 years before for chronic myelogenous leukemia.

A 31-year-old patient developed chronic myelogenous leukemia (CML) in November, 1983. In November 1984, following a diagnosis of acceleration, he received an autologous hemopoietic transplant after conditioning with cyclophosphamide and total body irradiation. The autologous marrow was purged with mafosfamide. Over 20 years, the patient remained in chronic phase of CML. Multiple nonrecurrent clonal chromosomal abnormalities appeared leading to a very complex karyotype, including among others involvement of chromosomes 1, 7, 9, 13, 19, and X. Fluorescent in situ hybridization showed that the two chromosomes 9 were involved. Acute myeloid crisis was diagnosed in February, 2004. Treatment with imatinib mesylate resulted within 6 months in a total disappearance of all chromosomal abnormalities with a complete cytogenetic and molecular response, which persists 3 years later. We question whether the ex vivo purging procedure with mafosfamide has favored the occurrence of these particular cytogenetic abnormalities (with no independent oncogenic potential) within the original leukemic stem cell pool. It remains unclear whether the autologous transplantation has indeed resulted into some prolongation of the duration of the chronic phase, which lasted for 20 years. At time of acute crisis, the dramatic response to imatinib mesylate leading to a complete cytogenetic and molecular response is noteworthy.

Functional interactions between bile acids, all-trans retinoic acid, and 1,25-dihydroxy-vitamin D3 on monocytic differentiation and myeloblastin gene down-regulation in HL60 and THP-1 human leukemia cells.

Bile acids were shown previously to inhibit proliferation and to induce monocytic differentiation in HL60 human acute promyelocytic leukemia cells (A. Zimber et al., Int. J. Cancer, 59: 71-77, 1994). In this report, we hypothesized that bile acids may exert a positive cooperativity with two known inducers of leukemic cell differentiation, all-trans retinoic acid and 1,25(OH)2-vitamin D3. Our results provide evidence that bile acids induced the monocytic differentiation of HL60 and THP-1 human leukemia cells exposed to ineffective concentrations of these inducers. The protein kinase C (PKC) inhibitors H-7 (10 and 20 microM) and staurosporine (5 and 20 nM) modulated the effects of bile acids on HL60 cell differentiation. Most interestingly, bile acids are shown herein to down-regulate the expression of the serine protease myeloblastin gene involved in the differentiation of myeloid hematopoietic cells. In agreement with the recent identification of nuclear receptors for bile acids, our data suggest that functional interactions between nuclear bile acid signaling pathways, PKC, and nuclear receptors for retinoic acid and vitamin D3 are involved in the down-regulation of the myeloblastin gene and the induction of cell differentiation in human leukemic cells.

Mevalonate deprivation alters the induction of fos and myc by growth factors.

Besides cholesterol, mevalonate is the precursor of several isoprenoid compounds including the farnesyl moiety of isoprenylated proteins. Inhibition of mevalonate biosynthesis leads to a growth arrest that can be relieved by addition of mevalonate, but not of cholesterol. To get a better understanding of the mechanisms underlying this growth inhibition, we have investigated whether mevalonate derivatives are implicated in the early response to growth factors. Our results show that pretreatment of quiescent human fibroblasts with mevinolin, an HMG CoA reductase inhibitor, partially suppresses fos and myc mRNA accumulation in response to serum stimulation. This effect of mevalonate deprivation appears to be on the transcriptional regulation of fos and does not depend upon the nature of the initial events of signal transduction, since the same phenomenon was observed following EGF and TPA stimulation.

Activation of p21ras is not sufficient to ensure a complete G1 phase of the cell division cycle in mouse fibroblasts.

In the mouse BP-A31 fibroblasts, mRNAs coding the three isoforms (Ha, Ki, N) of ras are expressed, and there are no activating mutations in the codons 12, 13 or 61. We have produced a subline (Ras2) expressing an oestrogen-inducible v-Ha-ras gene. The contribution of v-Ha-ras to the overall p21ras-GTP content was evaluated by metabolic labelling with 32P. Surprisingly, p21ras-GTP complexes were predominant in the serum-deprived BP-A31 cells as well as in the Ras2 cells. The excess of p21ras-GTP was not due to the lack of the GTPase activating protein. In transient transfection experiments, the serum response element (SRE)-directed CAT was expressed in serum-deprived BP-A31 cells, and insulin caused a further two- to threefold increase in CAT activity. A dominant negative ras mutant (Ha-Ras Asn-17) cancelled both the basal and insulin-induced CAT expression in the BP-A31 but not in the Ras2 cells. Expression of v-Ha-ras in Ras2 cells did not relax their growth factor-dependence and oestradiol had only a minor mitogenic effect. We conclude that p21ras activation does not ensure a complete cell division cycle in these cells, and does not entirely account for the transduction of the mitogenic signal initiated by insulin.

Interleukin 1 stimulates cholesterol esterification and cholesterol deposition in J774 monocytes-macrophages.

The effects of interleukin 1beta (IL1) in the range of concentration of 10-30 ng/ml on cholesterol metabolism were investigated in the monocyte-macrophage cell line J774. IL1 enhanced cholesterol esterification by [14C]oleic acid and acyl-coenzyme A cholesterol acyl transferase activity in a dose-dependent manner. Incubation of IL1-treated cells with acetylated low density lipoproteins labelled with [3H]cholesteryllinoleate resulted in accumulation of radioactive cholesterol in free and esterified form. Concomitantly, IL1 increased the free and esterified cholesterol intracellular content measured by the cholesterol oxidase technique. The effect of IL1 on cholesterol esterification by oleic acid was not observed in the presence of cycloheximide or of the ACAT inhibitor Sandoz 58 035. IL1 also stimulated cholesterol esterification in other cell types such as human fibroblasts and murine endothelial and smooth muscle cells. The effect of IL1 is specific, since IL2 or tumor necrosis factor (TNF) exhibited no significant activity, whereas oncostatin M only slightly enhanced cholesterol esterification. Since cholesterol deposition is involved in the initiation and progression of the atherosclerotic lesions, these findings highlight the role of the inflammatory cytokine IL1 on this process.

Clinical value of PCR in diagnosis and follow-up of leukaemia and lymphoma: report of the third Workshop of the Molecular Biology/BMT study group.

The proceedings of the third workshop of the molecular biology/bone marrow transplantation (BMT) study group held in January 1991 in Verona, Italy. This workshop was convened to review progress in the application of molecular techniques to the diagnosis and follow-up of patients with chronic myeloid leukaemia (CML) as well as other haematologic malignancies. The results of polymerase chainreaction studies in 157 CML patients 1-90 months post BMT suggest that leukaemia is frequently detectable for the first 12 months but rarely detected thereafter except in patients known to have a high risk of relapse. In the acute leukaemias and lymphomas there is a rapidly increasing number of leukaemia-specific as well as clone-specific molecular markers now available for the detection of minimal disease. It may be possible to coordinate multi-center prospective studies to investigate the role of these markers in the diagnosis and follow-up of haematologic malignancies.

Multicentric evaluation of the MDR phenotype in leukemia. French Network of the Drug Resistance Intergroup, and Drug Resistance Network of Assistance Publique-Hôpitaux de Paris.

The wide discrepancies in the frequency of 'positive' samples for multidrug resistance (MDR) phenotype within the same type of tumor observed in the literature justified the need for the definition of consensus recommendations. To define standard techniques of MDR phenotype measurement, we ran a large multicentric evaluation of the different methods available. Thirty-six French centers participated in the study, and 742 samples of 2-10 x 10(6) viable cells were sent by overnight express mail between December 1993 and February 1996. The same batches of MRK16, 4E3 and UIC2 were used. Nineteen samples of leukemia (12 AML, 1 ALL, 6 lymphoproliferative syndromes) and six leukemic cell lines with different levels of MDR expression were tested. Five meetings reached agreement concerning the guidelines for each technique, except immunocytochemistry. The 19 fresh samples were tested by each center using one to four techniques among cytofluorometry, immunocytochemistry, functional tests and RT-PCR. Five samples were diagnosed as 'negative' according to local criteria, with few discordant results (0 to 16% of 'positive' results). For all the 14 remaining samples, large discrepancies were observed from center to center, and from one technique to another. No correlations could be found between techniques. Flow cytometric analysis of cells already exposed to MRK16 or control IgG2A, fixed in paraformaldehyde and sent to centers did not reduce the discrepancies between centers in two of the four samples with moderate expression, emphasizing the role of histogram interpretation. The use of alternative monoclonal antibodies (4E3 and UIC2) did not reduce the discrepancies observed. In a second step, the K562 parental cell line, a low resistant subline (K562/HHT100, x7 resistance index to DNR) and a high resistant subline (K562/HHT300, x125 resistance index to DNR) were sent blindly three times, with an increasing level of recommendations for flow cytometry. Dramatic improvements were observed in cytometric results when the result was expressed as the ratio of arithmetic mean of fluorescence of antibody (10 microg of MRK16)/arithmetic mean of fluorescence of control (10 microg IgG2A): the proportion of expected results increased from 61 to 100% for K562, and from 37 to 85% for K562/HHT100. For uptake and drug efflux measurements, the use of 1 h uptake of 0.1 microM of rhodamine, followed by 1 h efflux +/-10 microM of verapamil, permitted an increased reproducibility of the technique from 71 to 100% for K562 and K562/HHT100. Whatever the technique used, concordant results were obtained for K562/HHT300. The immunocytochemistry, using several antibodies (MRK16, JSB1 and C219) gave many non-interpretable results (44%), due to a frequent high background and discordant results between antibodies in the same centers, and discordant conclusions between centers. The group does not recommend this technique for circulating tumoral cells.

French multicentric evaluation of mdr1 gene expression by RT-PCR in leukemia and solid tumours. Standardization of RT-PCR and preliminary comparisons between RT-PCR and immunohistochemistry in solid tumours. French Network of the Drug Resistance Intergroup, and Drug Resistance Network of Assistance Publique-Hôpitaux de Paris.

Since there is no consensus on the techniques for multidrug resistance (MDR) phenotype evaluation, many discrepancies concerning the importance and frequency of mdr1 gene expression in leukemias and solid tumors are observed in the literature. In order to establish an inter-laboratory consensus in France, a multicenter study was carried out to propose further guidelines for MDR phenotype evaluation. The techniques used by the 38 laboratories participating in the trial were: immunodetection (immunohisto and/or cytochemistry, flow cytometry), functional tests, reverse transcription-polymerase chain reaction (RT-PCR) or Northern blot. We present the results obtained by 19 laboratories concerning the measurement of mdr1 gene expression assessed by RT-PCR or Northern blot in: (1)19 samples of tumor cells obtained from leukemic patients; (2) six solid tumor samples obtained at surgery; (3) eight cell lines exhibiting variable levels of resistance, and; (4)10 preparations of RNA and of cDNA obtained from solid tumors. Standardization of the RT-PCR technique and preliminary results comparing RT-PCR with immunohistochemistry in solid tumors are also reported.

Detection of BCR/ABL translocation by polymerase chain reaction in leukemic progenitor cells (ALL-CFU) from patients with acute lymphoblastic leukemia (ALL).

In about 30% of cases, BCR/ABL transcripts are present in freshly isolated mononuclear cells from the bone marrow of patients with acute lymphoblastic leukemia (ALL) using the polymerase chain reaction (PCR) technique. We applied PCR to investigate the leukemic nature of ALL colony-forming unit (ALL-CFU) colonies grown in a clonogenic assay using a double feeder system. The high sensitivity of PCR enables us to detect 1 leukemic cell among 10(5) normal cells. Several controls were taken to assess contamination. In this report we studied three patients with ALL. In all of them, BCR/ABL transcripts were detected at initial diagnosis. We showed that the PCR technique could identify the leukemic nature of ALL-CFU progenitors. In addition, we demonstrated the nonleukemic nature of granulocyte-macrophage colony-forming unit (CFU-GM) and erythroid burst-forming unit (BFU-E) colonies using the same analysis. We conclude that the PCR technique is of great value in the identification of leukemic clones whenever specific molecular markers are present.

The role of serum lipoproteins on the in vitro proliferative potential of human hematopoietic progenitors CFUC and CFUE.

The influence of various lipoprotein fractions on the proliferation of normal human hematopoietic progenitors, CFUC and CFUE, was studied in vitro. The lipoprotein fractions, very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), low density lipoproteins (LDL), high density lipoproteins (HDL2 and HDL3), were isolated by sequential ultracentrifugation. The addition of each subfraction to lipoprotein deficient medium allowed us to distinguish two categories of lipoproteins: firstly, those with density d greater than 1.030, LDL, HDL2 and HDL3 which showed a marked inhibitory activity on CFUC and CFUE proliferation and, secondly, those with density d less than 1.030, VLDL and IDL which did not show any inhibitory activity. The regulatory role of lipoproteins on progenitor cell proliferation is discussed.

Phosphate dilution lowers net phosphatidyl choline synthesis in lymphocytes.

The rate of net phosphatidyl choline (PC) synthesis in lymphocytes was evaluated, under appropriate conditions, in terms of [32P]phosphate incorporation. Phosphate-diluted and normal media were compared, with the cells being stimulated by concanavalin A or not. In either case, incubation in phosphate-diluted medium lowered net PC synthesis. In concanavalin A-stimulated cells, phosphate dilution also abolished the stimulation effect on net PC synthesis in G1. Nevertheless, these changes did not inhibit blastogenic transformation of cells.

[Inhibition by the high density lipoprotein HDL2 and HDL3 of DNA and sterol biosynthesis in human lymphocytes stimulated with concanavalin A]. / Inhibition par les lipoprotéines de haute densité HDL2 et HDL3 de la synthèse du DNA et des stérols des lymphocytes humains stimulés par la concanavaline A.

Lipoproteins HDL2 and HDL3 inhibit DNA synthesis and sterol synthesis in human Con A-stimulated lymphocytes cultured in a medium supplemented with 20 per cent lipoprotein deficient serum. On the basis of the amount of proteins added, HDL2 is more efficient on DNA and sterol synthesis than HDL3 and less efficient than LDL. However, on the basis of the amount of cholesterol added, the inhibition of sterol synthesis induced by these three lipoproteins is not significantly different. At all concentrations of these three lipoproteins, the inhibition of sterol synthesis is higher than the inhibition of DNA synthesis.

Human placental microvilli as a source of antigen for the preparation of a polyclonal antibody directed against the LDL receptor.

Polyclonal antibodies were prepared by immunization of rabbits with partially purified LDL receptor obtained from human placental microvilli. The antiserum reacted with membranes from human placental microvilli and human fibroblasts, as assessed by immunobinding studies. It also reacted with purified LDL receptors of both origins. The antiserum markedly inhibited 125I-labeled LDL binding to cultured human fibroblasts.

Effect of AY 9944 and chlorpromazine on Concanavalin A-induced stimulation of human lymphocytes.

Amphiphilic molecules AY 9944 and chlorpromazine (CPZ) inhibited DNA synthesis in Concanavalin A-stimulated lymphocytes in a dose-dependent manner. While AY 9944 strongly decreased 7-dehydrocholesterol conversion to cholesterol, CPZ did not significantly affect this reaction. Moreover, the inhibitory effect of AY 9944 and CPZ on DNA synthesis took place in the presence of cholesterol in the culture medium. These findings suggest that the mechanism of inhibition of DNA synthesis by AY 9944 or CPZ is not related to endogenous cholesterol synthesis or exogenous cholesterol supply. Results are discussed in relation to the amphiphilic properties of AY 9944 and CPZ and to the interaction of these drugs with membranes or other intracellular targets such as calmodulin.

Interferon gamma is effective for BM purging in a patient with CML.

We report a case of Ph-positive CML where the BM was incubated for 24 h with 10(3) IU/ml IFN gamma and then cultured in liquid media for 4 weeks. After 24 h incubation, there was no differential sensitivity of CML CFU-GM to IFN gamma compared with untreated BM. Subsequent long-term culture (LTC) of the IFN gamma treated CML BM, however, demonstrated a 75% inhibition of production of CFU-GM from the second week onwards. Using PCR, we were able to demonstrate two types of BCR-ABL transcript in the diagnostic BM. After 4 weeks of LTC, the J(bcr b3/ABL II) RNA transcript persisted in the untreated BM, whereas neither BCR/ABL RNA transcripts were detected in the culture established with IFN gamma-treated CML BM. This study has two points of interest with the demonstration of (1) a possible antileukaemic effect of IFN gamma on the progenitors generated in the LTC system, and (2) the use of highly sensitive PCR technology to evaluate the effectiveness of IFN gamma to purge CML BM of Ph-positive cells.

Polymerase chain reaction: a method for monitoring tumor cell purge by long-term culture in BCR/ABL positive acute lymphoblastic leukemia.

We report the successful purging of leukemia cells bearing the Philadelphia chromosome and BCR/ABL transcripts by long-term marrow culture (LTC), and subsequent grafting of the purged marrow in a case of refractory acute lymphoblastic leukemia. The efficiency of the purge was evaluated by polymerase chain reaction (PCR) for BCR/ABL transcripts. In two LTCs initiated in the blastic stage, we demonstrated the selective effect of three culture media (serum dependent, serum-free (SF) supplemented or not with IL3 and GM-CSF) on the proliferative potential of normal hematopoietic (CFU-GM/BFU-E) and leukemic progenitors (CFU-ALL). BCR/ABL positive cells disappeared after 3 to 4 weeks of culture. The addition of IL3 and GM-CSF to the SF medium enhanced the growth of CFU-GM/BFU-E and shortened the purging period. We therefore carried out a LTC in the presence of IL3 and GM-CSF with marrow harvested in morphological remission. BCR/ABL positivity was detected at the outset, although no leukemia cells could be identified. The BCR/ABL was no longer found by PCR in the 7 and 14 day LTCs. The patient, consolidated by high dose polychemotherapy and total body irradiation, was infused with the 14 day LTC. This study indicates that PCR is a useful and sensitive technique for monitoring tumor cell reduction after LTC prior to autografting.