Biomedical subjects

R R De Krijger

Publications and source records attributed to R R De Krijger.

8 recordsLinked to original sources

PubMed2006

Genetic analyses of apparently sporadic pheochromocytomas: the Rotterdam experience.

Pheochromocytomas (PCCs) are neuroendocrine tumors of chromaffin tissue that produce catecholamines. They are usually located in the adrenal medulla, although in about 10% the tumors arise from extra-adrenal chromaffin tissue. The majority of PCCs arise sporadically, but PCCs occur also in the context of hereditary cancer syndromes. Familial PCC is inherited as an autosomal dominant trait alone or as a component of the multiple endocrine neoplasia Type 2 (MEN2) syndrome (RET gene), Von Hippel-Lindau (VHL) disease (VHL gene), neurofibromatosis Type 1 (NF1 gene), or familial pheochromocytoma-paraganglioma (PCC-PGL) syndrome (SDHD/B and C genes). It has been reported that 24% of apparently sporadic PCCs patients harbor germline mutations in these PCC-causing genes. We investigated the contribution of the inherited PCC-causing genes in a partly retrospectively and partly prospectively obtained series of 213 apparently sporadic PCCs. Mutation analysis was performed for RET (56 cases), VHL (136 cases), and SDHD (126 cases) and SDHB (47 cases). No germline RET mutations, six (4.4%) germline VHL mutations, two (1.5%) germline SDHD mutations, and one germline (1.6%) SDHB mutation were found. In total we found germline mutations in about 7.5% of the investigated apparently sporadic PCCs. Although 7.5% germline mutations in a series of apparently sporadic PCCs are far less than the more than 20% reported in the literature, the figure is significant enough to consider germline mutation testing for each patient with PCC.

Adrenal Gland Neoplasms↗

PubMed2004

Cellular composition of pancreas-associated lymphoid tissue during human fetal pancreatic development.

AIM: To study human fetal pancreatic tissue between 15 weeks of gestation and term, analysing the development of pancreatic lymphoid tissue and focusing on the presence and maturational status of dendritic cells (DCs). During normal human fetal pancreatic development lymphoid tissue arises in and around the pancreas. DCs are antigen-presenting cells which are capable of initiating immunity, but are also essential in inducing and maintaining T-cell tolerance. METHODS AND RESULTS: First, the presence and general composition of intra- and peripancreatic lymphoid tissue was investigated by histology and immunohistochemistry with antibodies to CD3, CD4, CD8, CD14, CD20, CD68, and CD79. Intrapancreatic lymphoid tissue (IPLT) appeared to be present only from 29 weeks of gestation onwards, and had a similar composition to peripancreatic lymphoid tissue (PPLT), which was found in all 23 specimens examined. Both forms of lymphoid tissue had an architecture similar to lymph nodes, with separate B- and T-lymphocyte areas and scattered macrophages. DCs were investigated in detail by immunohistochemistry for CD1a, CD83, CD86, CD123, Langerin, and DC-LAMP. Both Langerin, a marker for immature DCs, as well as DC-LAMP, a marker for mature DCs, were expressed by cells in both the IPLT and PPLT at all ages examined. CONCLUSION: The presence of DCs at all developmental stages, expressing various maturation-related markers, in addition to the general composition of the human fetal PPLT and IPLT suggests that this is fully functional and has a function comparable to peripheral lymph nodes.

Antigens, CD↗

PubMed2002

Thyroid transcription factor-1 expression during normal human lung development and in patients with congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Thyroid transcription factor-1 (TTF-1) was detected in human respiratory epithelial cells from 11 weeks of gestation. TTF-1 is involved in both lung morphogenesis and in the regulation of surfactant proteins. Recently, low expression of TTF-1 in the nitrofen rat model of congenital diaphragmatic hernia (CDH) was shown and restoration of this downregulation by antenatal glucocorticolds (CS) was reported. The aim of this study was to investigate the expression of TTF-1 as a marker of lung morphogenesis in normal human lung development and in age-matched controls of human lung specimen in hypoplastic lungs of human CDH and other forms of lung hypoplasia. METHODS: Immunohistochemistry by a monoclonal TTF-1 antibody was performed on paraffin sections of human fetal and neonatal lung tissues. The so-called developmental group (12 weeks' gestation to full term) included 47 lung specimens. The congenital hypoplasia group included 8 full-term CDH patients who died within 12 hours after birth, 3 full-term CDH patients who had antenatal CS therapy, and 4 full-term CDH patients after extracorporeal membrane oxygenation (ECMO) therapy. For comparison, 6 full-term born patients, who died of other forms of pulmonary hypoplasia, were used as comparative specimen. Immunohistochemical localization of TTF-1 was evaluated by light microscopy for 3 different areas of the airways including intrapulmonary bronchi, intermediate airways so-called terminal bronchioles, distal airways, and later sacculi and alveoli. RESULTS: Nuclear TTF-1 staining was observed in the progenitor cells of the developing bronchiolar cells early in the human lung developmental series. At full term, TTF-1 was expressed in both type II epithelial cells and in subsets of respiratory nonciliated bronchiolar epithelial cells in a pattern similar in all studied groups. No TTF-1 expression was detected at the level of the intrapulmonary bronchi. CONCLUSIONS: No difference in TTF-1 expression was observed in the developing early fetal and full-term neither in hypoplastic human lungs. This expression did not change with antenatal CS and postnatal ECMO treatment. Although TTF-1 appears to play an important role in lung morphogenesis, a pivotal role in human lung development is not likely.

Fetus↗

PubMed2001

Localization and potential role of matrix metalloproteinase-1 and tissue inhibitors of metalloproteinase-1 and -2 in different phases of bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) can evolve in prematurely born infants who require mechanical ventilation because of hyaline membrane disease (HMD). The development of BPD can be divided in an acute, a regenerative, a transitional, and a chronic phase. During these different phases, extensive remodeling of the lung parenchyma with re-epithelialization of the alveoli and formation of fibrosis occurs. Matrix metalloproteinase-1 (MMP-1) is an enzyme that is involved in re-epithelialization processes, and dysregulation of MMP-1 activity contributes to fibrosis. Localization of MMP-1 and its inhibitors, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2, were investigated in lung tissue obtained from infants who died during different phases of BPD development. In all studied cases (n = 50) type-II pneumocytes were found to be immunoreactive for MMP-1, TIMP-1, and TIMP-2. During the acute and regenerative phase of BPD, type-II pneumocytes re-epithelialize the injured alveoli. This may suggest that MMP-1 and its inhibitors, expressed by type-II pneumocytes, play a role in the re-epithelialization process after acute lung injury. Although MMP-1 staining intensity remained constant in type-II pneumocytes during BPD development, TIMP-1 increased during the chronic fibrotic phase. This relative elevation of TIMP-1 compared with MMP-1 is indicative for reduced collagenolytic activity by type-II pneumocytes in chronic BPD and may contribute to fibrosis. Fibrotic foci in chronic BPD contained fibroblasts immunoreactive for MMP-1 and TIMP-1 and -2. This may indicate that decreased collagen turnover by fibroblasts contributes to fibrosis in BPD development.

Autopsy↗

PubMed1999

MEN1 gene mutation analysis of sporadic adrenocortical lesions.

To clarify the role of the MEN1 gene in the tumorigenesis of sporadic adrenocortical tumors, we performed a molecular study on 35 adrenocortical lesions including 6 hyperplasias, 19 adenomas and 10 carcinomas. Loss of heterozygosity (LOH) of the MEN1 gene was assessed by PCR using an intragenic (D11S4946) and 2 flanking microsatellite markers (D11S4936, PYGM) and/or fluorescence in situ hybridization (FISH) with a 40-kb cosmid probe containing the MEN1 gene. The complete coding sequence of the MEN1 gene was screened for mutations using non-radioactive, PCR-based single-strand conformation polymorphism (SSCP) analysis and MDE heteroduplex gel electrophoresis. PCR-LOH and FISH analyses performed in 29 tumors (PCR-LOH in 4, FISH in 17 and both in 8 tumors) revealed allelic deletion of the MEN1 locus in 8 (27.5%) and at 11q13 in 9 (31%) tumors. Furthermore, the frequency of LOH at 11q13 was significantly higher in adrenocortical carcinomas (60%) than in benign lesions (11%). Mutation analysis of tumor samples revealed 9 polymorphisms in 7 tumors (S145S, R171Q, R171Q together with L432L) but no mutations, with the exception of one adrenocortical adenoma. The latter tumor contained a somatic E109X stop codon mutation in exon 2 and a 5178-9G-->A splice mutation in intron 4, which was also detectable in various nontumorous tissues and blood indicative of a germ-line mutation. The patient, who had no clinical signs or family history of MEN1, later also developed a neuroendocrine carcinoma (atypical carcinoid) of the lung. Our findings indicate that inactivating mutations of the MEN1 tumor-suppressor gene appear not to play a prominent role in the development of sporadic hyperplastic or neoplastic lesions of the adrenal cortex and that the newly reported 5178-9G-->A splice mutation in intron 4 might cause a variant of the MEN1 phenotype.

Adrenal Cortex↗

PubMed1999

Immunohistochemical detection of somatostatin receptor subtypes sst1 and sst2A in human somatostatin receptor positive tumors.

Although in situ hybridization has been used to examine the distribution of messenger RNA for somatostatin receptor subtypes (sst) in human tumors, the cellular localization of sst1 and sst2A receptors has not been reported. In this study, we describe the cellular localization of human sst1 and sst2A receptor proteins in both cryostat- and paraffin-embedded sections of 25 human tumor tissues using two recently developed polyclonal antibodies. Six somatostatin (SS) receptor (SSR) positive tumors (two gastrinomas, three carcinoids, one pheochromocytoma) and one SSR negative tumor (renal cell carcinoma), selected by positive and negative SSR autoradiography, respectively, were studied by both immunohistochemistry and Western blot analysis. The six SSR positive tumors expressed sst2A, while 4 of 5 expressed sst1 as well. The SSR negative tumor did not express either sst1 or sst2A. Western blot analysis of wheat germ agglutinin purified membrane proteins confirmed the presence of the sst1 and sst2A glycosylated receptors. The paraffin-embedded sections gave best information with respect to the subcellular localization. Sst1 immunoreactivity was observed both on the membrane and in the cytoplasm, while sst2A showed predominantly membrane-associated immunoreactivity. This subcellular distribution of sst1 or sst2A receptors was confirmed in paraffin-embedded sections of 8 additional intestinal carcinoids, 5 gastrinomas and 5 pheochromocytomas. Sst1 receptors were detected in 7 out of 8 carcinoids, in all gastrinomas, and in 4 out of 5 pheochromocytomas, while 6 out of 8 carcinoids, all gastrinomas, and 3 out of 5 pheochromocytomas expressed sst2A receptors. In conclusion, sst1 and sst2A receptors show a differential subcellular localization in human SSR positive tumors. The use of SSR subtype selective antibodies to detect the subcellular distribution of SSR subtypes in individual tumor cells is an important step forward to understand more about the pathophysiological role of the different SSR subtypes in human tumors.

Adrenal Gland Neoplasms↗

PubMed1992

The midgestational human fetal pancreas contains cells coexpressing islet hormones.

In the fetal development of the mouse pancreas, endocrine cells have been found that express more than one hormone simultaneously. Our objective was to evaluate the existence of such cells in the human fetal pancreas. We found cells coexpressing two of the major pancreatic hormones (insulin, glucagon, and somatostatin) in sections of eight midgestational (12-18 weeks) pancreata and in 0-7% of cells in single-cell suspensions from midgestational pancreata. By electron microscopy, using granule morphology and immunoelectron microscopic techniques, we could confirm these findings and even detect cells containing three hormones. Morphologically different granules contained different immunoreactivities, suggesting parallel regulation of hormone production and packaging. In six newborn pancreata (born after 22-40 weeks of gestation), we could not find any multiple-hormone-containing cells. Subsequently, we evaluated whether multiple-hormone-containing cells proliferate by using pancreatic fragments and single-cell preparations at the light and electron microscopic level (six pancreata). No endocrine hormone-containing cells incorporated bromodeoxyuridine during a 1-hr culture period, indicating that these cells have lost the ability to proliferate under the conditions chosen. We conclude that, as in mice, the human fetal pancreas of 12-18 weeks of gestation contains endocrine cells that express multiple hormones simultaneously. These (multiple) hormone-containing cells do not seem to proliferate under basal conditions.

Bromodeoxyuridine↗

PubMedDate not supplied

CHARGE association-related ocular pathology in a newborn with partial trisomy 19q and partial monosomy 21q, from a maternal translocation (19;21) (q13.1;q22.3).

We report a novel case of partial trisomy 19q and concomitant partial monosomy 21q, segregated from a maternal translocation (19;21) (q13.1;q22.3), identified by spectral karyotyping. Clinical examination revealed dysmorphic features of the face and limbs, cleft palate, bilateral colobomas with associated bilateral colobomatous optic nerve cysts, hearing loss, and a cardiac anomaly. At autopsy, the dysmorphic features and cleft palate were confirmed. The ocular histopathology is described in detail and the cardiac anomaly was further specified. The combination of phenotype features is diagnostic of the CHARGE (coloboma, heart malformation, atresia choanae, retarded growth and development, and/or CNS anomalies, genital hypoplasia, ear anomalies and/or deafness) association. This case also has some phenotypic features in common with previous cases of partial trisomy 19q. The importance of a complete autopsy in cases with multiple congenital anomalies and/or genetic abnormalities is emphasized. This will allow optimal genetic counseling and contribute to our understanding of developmental biology.

Abnormalities, Multiple↗