PubMed Health⌕ Search

Biomedical subjects

M Pipeleers-Marichal

Publications and source records attributed to M Pipeleers-Marichal.

At least 19 recordsLinked to original sources

Formation of insulin-positive cells in implants of human pancreatic duct cell preparations from young donors.

AIMS/HYPOTHESIS: Pancreatic ducts are considered as potential sites for neogenesis of beta cells. In vitro studies have reported formation of islets from postnatal human and rodent duct tissue. We examined whether postnatal human duct-cell preparations can generate new beta cells after transplantation. METHODS: Pancreatic duct cells were prepared from the non-endocrine fraction of human donor pancreases that were processed for islet-cell isolation. Grafts containing 0.5 million duct cells with 1% contaminating insulin-positive cells were implanted under the kidney capsule of normoglycaemic nude mice. At 0.5 and 10 weeks post-transplantation, implants were examined for their cellular composition and for the volumes of their composing cell populations, i.e. cytokeratin 19-positive duct cells, synaptophysin-, insulin- and glucagon-positive endocrine cells. RESULTS: Between week 0.5 and 10, duct-cell volume decreased by at least 90% whereas the change in insulin-positive cell volume depended on donor age. Implants from donors over 10 years had a threefold decrease in their insulin-positive cell volume, while those from donors under 10 years had a 2.5-fold increase. After 10 weeks, the implants from the younger donors consisted of 19% insulin-positive cells occurring as single units or small cell clusters. Three percent of these insulin-positive cells also expressed the ductal marker CK 19 and were consistently found in conjunction with ductal epithelia; up to 1% was positive for the proliferation marker BrdU and located in small endocrine cell clusters. CONCLUSIONS/INTERPRETATION: These data indicate that duct cell preparations from donors under 10 years can generate insulin-positive cells. This process might involve differentiation of CK 19-positive-insulin cells that are formed at the duct epithelia as well as proliferation of insulin-positive cells within endocrine cell aggregates.

Adolescent↗

Mixed ductal-endocrine carcinomas of the pancreas and ductal adenocarcinomas with scattered endocrine cells: characterization of the endocrine cells.

We compared the histological and immunohistochemical features of mixed ductal-endocrine carcinomas of the pancreas with those of ductal adenocarcinomas (DACs) containing scattered tumor-associated endocrine cells (SECs). Three pancreatic neoplasms fulfilled the WHO criteria for mixed ductal-endocrine carcinomas. Two of them showed moderately to poorly differentiated glandular structures composed of both mucin producing and neuroendocrine cells. The third mixed ductal-endocrine carcinoma was of the composite type showing DAC structures and a solid component with small epithelial cells, most of them of neuroendocrine nature. In 32 of 34 cases of DAC located in the head (30 cases) and body to tail (4 cases) of the pancreas and showing lymph-node metastases, SECs were found, but they were few in number and irregularly distributed in the tumors. In three DACs a few SECs were also detected in lymph-node metastases. Double staining for chromogranin A and the proliferation marker Ki-S5 revealed that all SECs that were not intimately integrated into the neoplastic glandular epithelium failed to show proliferative activity and changes of the expression of tumor suppressor genes (p53 and DPC 4). These findings suggest that only those SECs that belong to the proliferative cell fraction may be of neoplastic origin, while the majority of SECs probably constitute a tumor-associated but non-neoplastic cell population. These features contrast with those of mixed ductal-endocrine carcinomas, in which all endocrine cells are a component of the neoplasm.

Adenocarcinoma↗

Loss of nuclear BRCA1 localization in breast carcinoma is age dependent.

Abstract. Patients carrying a germ line mutation in the BRCA1 gene are predisposed to breast cancer. Somatic BRCA1 mutations were almost never reported in sporadic breast tumors, but several authors have described a decrease in BRCA1 mRNA and protein. In order to further investigate the possible role of BRCA1 in sporadic breast cancer, an improved immunohistochemical protocol was developed and applied on tissue sections obtained from 102 cancer patients belonging to two nonoverlapping age groups (less than 40 and more than 60 years). Based on the obtained BRCA1 specific nuclear staining we could distinguish two categories of breast cancer. The staining was present in almost all the nuclei of the normal and the cancer cells in about 50% of young (less than 40 years old) as well as older patients (more than 60 years old). Thus, BRCA1 does not seem to be involved in the genesis of these cancers. In the second category of patients, either a fraction of, or all tumor cells showed no nuclear staining. In this category, no nuclear BRCA1 staining could be observed in the tumor cells of 14 (27%) young and 3 (6%) older patients. Among six young patients bearing a breast tumor showing no BRCA1 nuclear staining at all, one was found to carry a BRCA1 germline mutation. Taken together, our results suggest that the molecular pathway in which the BRCA1 protein participates is disturbed in about 50% of sporadic breast cancer, this effect being more pronounced in tumors of young patients.

Adenocarcinoma↗

Non-secreting atypical parathyroid adenoma.

Parathyroid tumors can be divided in adenomas and carcinomas, usually detected by hypercalcemia. We report a case of parathyroid adenoma in a young man, who complained of a pressure in the left neck region. Physical examination revealed a firm mass in the neck, without lymphnodes. Although Ca (9.7 mg/dl), phosphorus (3.3 mg/dl) and intact-PTH (49 pg/ml) were normal, imaging techniques (computed tomography scan and sestamibi substraction scan) suggested that the mass could arise from the parathyroid gland. Histology and immune staining for chromogranin and parathyroid hormone confirmed the parathyroid nature of the mass. Histological criteria defined the lesion as an atypical parathyroid adenoma. We review the pathology, diagnosis and treatment of parathyroid adenomas in its non-secreting atypical form.

Adenoma↗

Endocytosis of low-density lipoprotein by human pancreatic beta cells and uptake in lipid-storing vesicles, which increase with age.

Studies with I(125)-labeled low-density lipoproteins (LDLs) have shown the presence of high-affinity LDL receptors on insulin-producing beta cells but not on neighboring alpha cells. By using gold-labeled lipoproteins, we demonstrate receptor-mediated endocytosis of LDLs and very low-density lipoproteins in rat and human beta cells. Specific for human beta cells is the fusion of LDL-containing endocytotic vesicles with lipid-storing vesicles (LSVs; diameter, 0.6-3.6 microm), which are absent in rodent beta cells. LSVs also occur in human pancreatic alpha and duct cells, but these sequester little gold-labeled LDL. In humans <25 years old, LSVs occupy 1% of the cytoplasmic surface area in beta, alpha, and duct cells. In humans >50 years old, LSV surface area in beta cells (11 +/- 2% of cytoplasmic surface area) is fourfold higher than in alpha and duct cells and 10-fold higher than in beta cells at younger ages (P < 0.001); the mean LSV diameter in these beta cells (1.8 +/- 0.04 microm) is larger than at younger ages (1.1 +/- 0.2 microm; P < 0.005). Oil red O staining on pancreatic sections confirms that neutral lipids accumulate in beta cells of older donors. We conclude that human beta cells can incorporate LDL and very low-density lipoprotein material in LSVs. The marked increase in the LSV area of aging human beta cells raises the question whether it is caused by prolonged exposure to high lipoprotein levels such as occurs in Western populations and whether it is causally related to the higher risk for type 2 diabetes with aging.

Adolescent↗

Implantation of standardized beta-cell grafts in a liver segment of IDDM patients: graft and recipients characteristics in two cases of insulin-independence under maintenance immunosuppression for prior kidney graft.

Islet allografts in insulin-dependent diabetic (IDDM) patients exhibit variable survival lengths and low rates of insulin-independence despite treatment with anti-T-cell antibodies and maintenance immunosuppression. Use of poorly characterized freshly isolated preparations makes it difficult to determine whether failures are caused by variations in donor tissue. This study assesses survival of standardized beta-cell allografts in C-peptide negative IDDM patients on maintenance immunosuppression following kidney transplantation and without receiving anti-T-cell antibodies or additional immunosuppression. Human islets were isolated from pancreatic segments after maximal 20 h cold-preservation. During culture, preparations were selected according to quality control tests and combined with grafts with standardized cell composition (> or = 50% beta cells), viability (> or = 90%), total beta-cell number (1 to 2 x 10(6)/kg body weight) and insulin-producing capacity (2 to 4 nmol x graft(-1) x h(-1)). Grafts were injected in a liver segment through the repermeabilized umbilical vein. After 2 weeks C-peptide positivity, four out of seven recipients became C-peptide negative; two of them were initially GAD65-antibody positive and exhibited a rise in titre during graft destruction. The other three patients remained C-peptide positive for more than 1 year, two of them becoming insulin-independent with near-normal fasting glycaemia and HbA1c; they remained GAD65- and islet cell antibody negative. The three patients with surviving grafts presented a history of anti-thymocyte globulin therapy at kidney transplantation. Long-term surviving grafts increased C-peptide release following intravenous glucagon or oral glucose but not following intravenous glucose. Thus, cultured human beta-cells can survive for more than 1 year in IDDM patients on maintenance anti-rejection therapy for a prior kidney graft and without the need for an increased immunosuppression at the time of implantation. The use of functionally standardized beta-cell grafts helps to identify recipient and graft factors which influence their survival and metabolic effects. Insulin-independence can be achieved by injection of 1.5 million beta-cells per kg body weight in a liver segment. These beta-cell implants respond well to adenylcyclase activators but poorly to glucose.

Adolescent↗

Dexamethasone alters messenger RNA levels but not synthesis of collagens, fibronectin, or laminin by cultured rat fat-storing cells.

Glucocorticoids have been shown to suppress collagen synthesis and gene expression by fibroblasts. However, little is known about their effects on fat-storing cells, the major matrix-producing cells in liver fibrosis. In this study we investigated the effect of dexamethasone on the extracellular matrix expression by cultured rat fat-storing cells. Fat-storing cells were isolated from male Wistar rats by collagenase/pronase digestion and purified by density gradient centrifugation. Fat-storing cells in early primary culture (3-day-old, representing a relatively quiescent phenotype) and in subculture (one passage, about 2-week-old, representing an activated phenotype) were treated with 10(-6) mol/L dexamethasone for messenger RNA (mRNA) study or with 10(-8) to 10(-6) mol/L dexamethasone for protein study. Expression of collagen type I, III, IV, fibronectin, and laminin was analyzed at the mRNA level by Northern hybridization, and at the protein level by metabolic labeling and immunoprecipitation. Dexamethasone had a variable effect on the expression of collagen alpha1(I) mRNA level. While a tendency for modest suppression was observed (5%-50%) in primary cells, the difference was not statistically significant. Variable response was observed in subcultured cells. Collagen alpha1(III) mRNA level showed a tendency for stimulation. Dexamethasone stimulated the expression of collagen alpha1 (IV), fibronectin, and laminin B1 mRNA levels by 1.4-, 2.4-, and 1.6-fold respectively, in primary fat-storing cells. Subcultured cells showed a similar response, but the magnitude of stimulation was more variable than that of primary cells. Unexpectedly, at the protein level dexamethasone had no effect on the expression of these proteins. Our results indicate that glucocorticoids do not possess a net suppressive effect on extracellular matrix synthesis by fat-storing cells. Beneficial effects of glucocorticoids may be attributable to other mechanisms of action, such as their anti-inflammatory effect.

Animals↗

Peroxisome proliferation associated with fibrinogen storage in the liver.

We report a patient with fibrinogen storage disease in which there was proliferation of normal-sized peroxisomes in the hepatocytes. this phenomenon has previously been described in several acquired liver diseases. We believe that this is an adaptation response due to decreased microsomal isoenzyme activity as a result of the excess accumulation of fibrinogen in the endoplasmic reticulum.

Child↗

Increasing serum levels of alpha-fetoprotein in a patient with relapsing gallbladder carcinoma.

Alpha-fetoprotein (AFP) is a useful serum tumor marker especially for hepatocellular carcinoma and yolk-sac tumor. Increased serum levels of AFP have also been found in adenocarcinoma of the stomach, the pancreas, the colon and the lung, and in some squamous cell carcinomas of the lung. We describe a patient with a recurrent gallbladder carcinoma, presenting with increasing serum levels of AFP as the tumor progresses. Remarkable are the histologic changes in the metastases of the tumor, which showed more dedifferentiation as the number of cells containing AFP increased.

Adenocarcinoma, Papillary↗

Effects of chronically elevated glucose levels on the functional properties of rat pancreatic beta-cells.

This study examines the effects of chronically elevated glucose levels on the survival and function of purified rat beta-cells. Prolonged exposure (9 days) of beta-cell aggregates to 20 mmol/l glucose did not lead to cell losses, but reduced the amount of insulin secreted in response to glucose. This decrease was not caused by cellular desensitization but resulted from the lower cellular insulin content after a prolonged imbalance between stimulated rates of insulin synthesis and release. Virtually all beta-cells exhibited a state of metabolic and biosynthetic activation, which was maintained for at least 2 h in glucose-depleted media. Their rates of protein and insulin synthesis were amplified by glucose, reaching (half-) maximal stimulation at lower glucose concentrations (2 and 5 mmol/l, respectively) than control cells cultured at 10 mmol/l glucose (5 and 10 mmol/l, respectively). As for insulin release, the net glucose effect on insulin synthesis was markedly reduced as compared with that in control cells. This was also the case after culture at 6 mmol/l glucose. In the latter condition, the lower glucose-inducible activities were caused by cellular desensitization, with 50% of the beta-cells unresponsive to glucose and the other 50% responding with a lower sensitivity (half-maximal stimulation at 7 mmol/l glucose). Comparison of beta-cells cultured at the three glucose concentrations indicated that prolonged exposure to elevated glucose levels increases the number of degranulated cells, of cells with a high proportion of immature insulin granules, and of cells with glycogen deposition-morphologic features previously described in conditions of hyperglycemia. It is concluded that chronic exposure (9 days) of rat beta-cells to elevated glucose levels induces a prolonged state of beta-cell activation and glucose hypersensitivity rather than a glucotoxicity or glucose desensitization. This shift in the functional state of the beta-cell population is responsible for a reduced insulin release in response to glucose, as observed in other conditions of prolonged exposure to high glucose levels.

Animals↗

Imaging of renal cell cancer with radiolabelled octreotide.

Recently the presence of somatostatin receptors on human renal cell carcinomas has been demonstrated by autoradiographic techniques on surgically removed kidneys. In a prospective study we evaluated, by means of 111In-labelled octreotide scintigraphy, the in vivo tumour imaging in a group of patients with biopsy proven renal cell carcinomas at different tumour stages. Seven patients were studied. In three of them (43%) pathological tracer accumulation was demonstrated. In these patients 20 out of 23 known tumour localizations were clearly visualized. Tracer uptake could be inhibited by prior administration of cold octreotide. We conclude that 111In-octreotide scintigraphy can be used to demonstrate, in vivo, metastatic renal cell carcinoma.

Aged↗

Esophagitis of likely traumatic origin in newborns.

We describe 17 full-term newborns presenting with vague symptoms related to the upper gastrointestinal tract (anorexia, poor feeding, retching, regurgitation, and incessant crying) during their stay in the maternity unit. After an esophagogastroduodenoscopy performed between days 2 and 5 of life, the babies could clearly be divided into two groups. Twelve babies (group 1) had an extremely severe esophagitis (circular ulcerations), without gastroduodenitis. In the remaining five babies (group 2), the upper gastrointestinal tract was unaffected. Allergic, infectious, metabolic, and toxic etiologies were excluded. Esophageal pH monitoring data were within normal ranges in all. All babies of group 1 were treated as follows: prone anti-Trendelenburg position, cisapride, and cimetidine syrup. Symptoms and lesions disappeared within 48-72 h. Reendoscopy after 72 h showed an almost normal esophagus with greatly improved histology. These observations highlight four points of interest: (a) the existence of an extremely severe ulcerative esophagitis in apparently healthy newborns, (b) the very rapid clinical and histological recovery, (c) the difficulties in predicting esophagitis on clinical grounds, and (d) the mysterious origin despite thorough assessment. The distribution of the lesions (more severe in the upper esophagus), the early onset (almost at birth), the very rapid healing, and the absence of gastric and duodenal lesions are in favor of a possible "traumatic" origin (pharyngeal, esophageal, and gastric suction at birth). Finally, because the condition described is transient, questions arise regarding the necessity of treatment, and we currently do not recommend overtreating newborns presenting with similar symptoms and/or endoscopic findings.

Duodenum↗

Contribution of the 13C-urea breath test to the detection of Helicobacter pylori gastritis in children.

Serology, 13C-urea breath test, histology, Campylobacter-like organism testing, and culture were performed in 95 consecutive children to evaluate the contribution of these tests to the detection of Helicobacter pylori infection. In analyses considering any combination of three positive tests as "gold standard" for diagnosing H pylori infection, 26 children were Helicobacter positive (27%), which is only one patient more than the number of children with only a positive culture. The accuracy of culture was excellent when "any combination of three positive tests" was used as the gold standard (sensitivity 96%, specificity 100%, positive predictive value 100% [false positivity 0%], negative predictive value 99% [false-negative results 1%]). The results of invasive and noninvasive tests were comparable. When culture was considered as "gold standard," the sensitivity of serology and 13C-urea breath test was 96%; the specificity was 96% and 93%, respectively; the positive predictive value was 89% and 83% (false-positive results in 11% and 17%); and the negative predictive value for both was 99% (false-negative results in 1%). It is concluded that culture can be used as gold standard, but that non-invasive tests such as serology and/or 13C-urea breath test can be used to diagnose H pylori infection in children, since each has at least 95% sensitivity and 92% specificity.

Adolescent↗

Surgical pathology of gastrinoma. Site, size, multicentricity, association with multiple endocrine neoplasia type 1, and malignancy.

Specimens from the pancreas and duodenum of 26 patients with sporadic Zollinger-Ellison syndrome (ZES) and 18 patients with multiple endocrine neoplasia type 1 (MEN-1) and hypergastrinemia (17 with ZES) were screened immunocytochemically for gastrinomas. Location, size, multicentricity, and malignancy of the gastrinomas were evaluated. The MEN-1 patients had gastrinomas in the duodenum (nine of 18), pancreas (one of 18), and periduodenal lymph nodes (two of 18). No gastrinoma was identified in six patients. Most duodenal gastrinomas were multiple (five of nine) and smaller than 0.6 cm (six of nine). Lymph node metastases were present in eight of 12 patients. All 26 patients with sporadic ZES had a solitary gastrinoma; 14 were found in the pancreas and had a diameter greater than 2 cm. Ten patients had a duodenal gastrinoma, two with a diameter less than 0.6 cm. In two patients, only periduodenal "lymph node gastrinomas" were detected. Eighteen of the sporadic gastrinomas were malignant. These results suggest that duodenal location and multicentricity of gastrinomas are associated with the MEN-1 syndrome, and solitary gastrinomas, either in the pancreas or the duodenum, are predominantly seen in sporadic ZES.

Duodenal Neoplasms↗