[Guideline 'The chronically ill and work']. / Richtlijn 'Chronisch zieken en werk'.

- The guideline 'The chronically ill and work' gives insight into disease-overarching factors and interventions that can promote or impede the participation in the work process of workers and those looking for work who have a chronic condition. - In particular, the guideline focuses on the role taken on by workers or those looking for work themselves during the process of keeping or resuming work. - The guideline gives recommendations for the daily practice of healthcare providers which are based on knowledge from disease-specific guidelines, the international literature and the experiences of healthcare providers, and workers and those looking for work with a chronic condition.

The status of p53 in the metastatic progression of colorectal cancer.

In order to investigate the role of TP53 in tumour progression and metastasis, we analysed 33 liver metastases of colorectal carcinomas and 19 primary colon carcinomas from the same hospital with respect to mutational changes, loss of heterozygosity and expression of the TP53 tumour suppressor gene. Direct sequencing of PCR products corresponding to the coding region of TP53 revealed that 13 of 19 primary tumours (68%) and 23 of 33 liver metastases (70%) had mutations in the TP53 gene. The distribution of mutations along the coding region of TP53 was similar in liver metastases compared to primary tumours. Thus, codon specificity did not seem to be a relevant factor and cells carrying specific TP53 mutations seem to have no selective advantage in the metastasising process. Comparing our data with the mutational spectra found in other countries did not reveal differences in the distribution of mutations along the coding region. Most of the metastases analysed showed loss of heterozygosity (LOH, 9 of 12 cases, 75%) and strong nuclear staining in immunohistochemistry (10 of 17 cases, 59%). Furthermore, with respect to mRNA expression levels, tumours carrying TP53 mutations showed significantly higher p53 mRNA levels compared to those without TP53 mutations. Thus, regulation of p53 mRNA levels seems to be subject to selection processes in tumourigenesis.

MDR1 expression correlates with mutant p53 expression in colorectal cancer metastases.

Overexpression of the multidrug resistance MDR1 gene is thought to contribute to drug resistance in non-responsive cancers like colorectal carcinoma. Little is known about the mechanisms by which expression of MDR1 is regulated in human tumours. However, there is growing evidence that regulation primarily takes place at the transcriptional level and that the process of tumour progression is related to activation of the MDR1 gene. Mutations in the p53 tumour-suppression gene occur in approximately 70% of colorectal cancers. As a transcriptional regulator, p53 might be involved in regulation of MDR1 expression in these tumours. We therefore determined MDR1 expression using the differential polymerase chain reaction technique in 30 colorectal tumours (4 primaries and 26 metastates) and correlated our results with previously reported data on p53 in the same group of patients. We found a significant positive correlation between p53 and MDR1 expression in p53-mutated tumours (P = 0.005; r = 0.596), but not in tumours without a p53 mutation. In addition, we observed a tendency towards higher MDR1 expression levels in tumours carrying p53 mutations (P = 0.14) compound to wild-type p53 tumours. These data indicate that mutant p53 may play a role in the regulation of MDR1 expression in human cholorectal cancer.

[Family planning as part of preventive health care]. / Familieplanlegging som en del av det forebyggende helsearbeid

PIP: The World Health Organization has a 5-point family planning program. They give counseling to the subfertile, to women who wish to monitor or regulate their fertile periods, to parents concerning their family responsibility, and to people who need any kind of counseling for emotional or sexual problems. Scientific research in the areas of sterility and fertility comprises the 5th point of the program.^ieng

Promoter is an important determinant of developmentally regulated puffing at the Sgs-4 locus of Drosophila melanogaster.

Sgs-4 is one of the eight known genes coding for larval secretion proteins in Drosophila melanogaster. High-level transcription of the endogenous Sgs genes in salivary glands is accompanied by chromosome puffing at the Sgs gene loci. Naturally occurring mutations of the Sgs-4 promoter region diminish both the level of Sgs-4 expression and the puff size; in null-producers no puff is formed. P element-mediated transformation experiments were performed to clarify this apparent causal relation between transcription and puffing. Sgs-4 upstream sequences, unchanged or recombined with sequences from differently expressed alleles, were fused with Sgs-4 coding and downstream sequences or with the coding sequence of the viral oncogene v-mil. Analyses of the expression of these fragments at the RNA and protein levels and of their capacity for puff formation demonstrate uncoupling of transcription and puffing. That is, high-level transcription is independent of chromosome puffing and does not necessarily induce puffing, and developmentally regulated chromosome puffing is independent of significant transcriptional activity within the puff. Our results show that the strength of the Sgs-4 promoter located within the upstream region from -1 to -840 determines the formation of a puff. No specific effects could be detected on either transcription or puffing by decondensed versus compact chromatin adjoining the transposed DNA at the sites of insertion in transformants. A model in which trans-acting factors binding to the promoter region initiate puffing is proposed.

Detection of p53 mutations using nonradioactive SSCP analysis: p53 is not frequently mutated in myelodysplastic syndromes (MDS).

p53 is one of the most frequently mutated genes in human cancers. Since p53 has been implicated in lymphatic and some myeloid leukemias, such as the blastic phase of chronic myelogenous leukemia, we sought to address the role of p53 gene mutations within exons 4-9 in myelodysplastic syndromes (MDS), a myeloid preleukemic condition. In order to avoid the potential hazard of using radioactive single-strand conformation analysis (SSCP), we used a nonradioactive SSCP method based on the silver stain of small minigels. In cell lines with known point mutations of the p53 gene, aberrant migrating bands were found. Serial dilutions indicated a sensitivity comparable to radioactive methods. Furthermore, a common polymorphism within the 4th exon of the p53 gene was easily detected. However, of 17 primary samples from patients with MDS, none harbored a p53 gene mutation. We conclude that this nonradioactive method can easily be used to screen for p53-gene mutations, and that p53-gene mutations do not play a major role in the pathogenesis of MDS.

Expression and mutational analysis of Nm23-H1 in liver metastases of colorectal cancer.

It has been proposed that nm23-H1, a candidate suppressor gene for metastasis, plays an important role in metastasis formation of human tumours. In order to investigate its role in the progression of colorectal cancer, we analysed 22 liver metastases of this malignancy with respect to mutational changes, loss of heterozygosity and expression levels of nm23-H1. Although genetic alterations in nm23-H1 have recently been described in those colorectal adenocarcinomas which give rise to distant metastases, we were unable to detect any mutation in the coding sequence of nm23-H1 in the metastatic tissue itself. We further analysed the metastases with respect to allelic deletions at the chromosomal locus of nm23. However, no loss of heterozygosity could be detected in ten informative cases. Moreover, the mRNA expression levels of nm23-H1 in the metastatic tissues were not significantly different from those in normal colon mucosa. Thus, although nm23-H1 might be involved in metastasis suppression of certain tumour types, in colorectal tumour progression its role remains to be determined.

Evidence for a mutual regulation of p53 and c-myc expression in human colorectal cancer metastases.

BACKGROUND: Alterations of the c-myc and the p53 genes occur in a majority of human colorectal cancers, and functional interaction between these two genes has recently been suggested. PATIENTS AND METHODS: We analyzed p53 sequence and c-myc and p53 mRNA expression in 26 metastases and 4 advanced primaries of human colorectal cancer. RESULTS: Twenty-one of 30 tumors (=70%) carried mutations of the p53 gene. In these samples, c-myc and p53 were overexpressed in 70% (15/21) and 71% (14/20) of evaluable cases, respectively, while in tumors carrying only wild-type p53, overexpression of c-myc and p53 was observed in only 33% (3/9; p < 0.05) and 22% (2/9; p < 0.01), respectively. Expression of p53 and c-myc were positively correlated (p = 0.014; r = 0.563) in tumors carrying a p53 mutation, but not in those with only wild-type p53. CONCLUSION: We conclude that c-myc might induce p53 expression in human colorectal cancer and that wild-type but not mutant p53 might be involved in a negative feedback regulation of c-myc expression. The abrogation of this normal control mechanism seems to be an essential step during colorectal tumorigenesis and metastatic progression.

PCR-determined expression of the MDR1 gene in chronic lymphocytic leukemia.

To determine the role the multiple drug-resistance (MDR 1) gene plays in chronic lymphocytic leukemia (CLL), we measured the expression of the MDR 1 gene in 30 patients with this disease. A rapid, highly sensitive, and nonradioactive technique based on the polymerase chain reaction (PCR) was used for that purpose. In this technique, called differential PCR, the target (MDR 1) and a reference gene (beta 2-microglobulin) are co-amplified by PCR from random hexamer-primed cDNA in the same reaction vessel. The level of target gene expression is reflected in the ratio between the intensities of the two resulting PCR product bands, as measured by high-performance liquid chromatography (HPLC). MDR 1 gene expression was detectable in 29/30 (97%) patients with CLL, with a median expression level of 0.36 U (human placenta = 1 U). There was no correlation between expression of the MDR 1 gene and clinical stage, time from diagnosis, absolute lymphocyte count, several lymphocyte surface markers, or prior treatment in the patients analyzed. Immunocytochemical studies of the same material using the monoclonal antibody C219 showed a very low or undetectable expression of the P-glycoprotein in the lymphocytes of all patients studied, whereas granulocytes were significantly more immunoreactive. We conclude that the level of expression of the MDR 1 gene in CLL is generally low, that the removal of granulocytes is important in studies of expression of MDR 1 mRNA in CLL, and that differential PCR provides a rapid and reliable method for quantifying the amount of a specific mRNA, even in very small samples of total RNA.

Molecular alterations in a patient with Turcot's syndrome.

Cells of a patient with Turcot's syndrome and of her parents were evaluated for the presence of molecular alterations in the p53 and the Ki-ras gene. Deletions on chromosome 17p, overexpression and point mutations of the p53 gene as well as mutations of the Ki-ras gene were detected in primary and metastatic tumour but not in the germline of the patient nor in her parents.

Position specificity of Ki-ras oncogene mutations during the progression of colorectal carcinoma.

The Ki-ras proto-oncogene is converted into an active oncogene by mutations in codon 12, 13, or 61. The incidence of mutations in the Ki-ras oncogene in colorectal adenomas and primary colorectal carcinomas has been shown to be 50-75 and 40-65%, respectively. To determine the role activation of the Ki-ras oncogene plays in the progression of colorectal carcinoma, we analyzed DNA from 11 nude-mouse xenografts and from 24 metastases of 22 patients with colorectal carcinoma, using the polymerase chain reaction technique and hybridization with labeled mutation-specific oligomers. Eleven of the 24 metastases (46%) carried mutations, 7 in codon 12 and 4 in codon 13, whereas only 1 nude-mouse tumor (9%) harbored a Ki-ras codon-12 mutation. Eleven of these 12 mutations in advanced stages of colorectal cancer were localized to the second position of either codon 12 or codon 13, whereas a majority of published ras mutations in earlier stages are in the first position of codon 12 of the Ki-ras oncogene. We conclude that there is a position specificity of Ki-ras oncogene mutations in advanced stages of colorectal carcinoma. In general, however, these mutations do not seem to play an important role in the progression of this cancer.

Regulation and possible function of axl expression in immature human mast cells.

The receptor tyrosine kinase Axl which expresses extracellular domains reminiscent of cell adhesion molecules, is involved in homotypic binding as well as in intracellular signaling of myeloid progenitor cells. In order to investigate factors which might influence differentiation pathways through changes of the adhesive properties of cells, we analyzed the expression of axl in immature basophil and mast cell lines and in cultured basophil and mast cell precursors. Axl expression was induced by interferon-alpha in the human leukemic mast cell line HMC-1 and in cultured mast cells derived from CD34+ peripheral blood cells. Axl induction was dose dependent, appeared within 1 h, and was independent of de novo protein synthesis. IFNalpha-treated HMC-1 cells expressing axl formed large cell aggregates within 40 h while untreated cells did not. HMC-1 cells also expressed gas6, the putative ligand of axl, which has been shown to induce axl-mediated homotypic binding. Gas6 expression was independent of interferon treatment in HMC-1 cells. The present results suggest that axl-mediated changes of cellular adhesive properties in mast cells may be important in mast cell differentiation as well as in mast cell-associated inflammation.