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Biomedical subjects

W W van Solinge

Publications and source records attributed to W W van Solinge.

16 recordsLinked to original sources
PubMed2002

[From gene to disease; hereditary non-spherocytic hemolytic anemia caused by pyruvate kinase deficiency].

Pyruvate kinase (PK) deficiency is a common cause of hereditary non-spherocytic haemolytic anaemia. It is an autosomal recessive disorder caused by mutations in the gene coding for erythrocyte and liver-type pyruvate kinase (PKLR). So far, more than 130 mutations in this gene have been identified. Clinical symptoms, usually restricted to homozygous and compound-heterozygous individuals, are variable, ranging from neonatal jaundice requiring erythrocyte transfusions to a fully compensated haemolytic anaemia. The exact mechanism of erythrocyte destruction is unknown, however adenosine-triphosphate depletion and an increase in 2,3-disphosphoglycerate are thought to be important. The diagnosis of pyruvate kinase deficiency depends upon the demonstration of low PK enzyme activity. Due to the pitfalls in determining true PK activity, DNA testing is a valuable tool in the diagnosis of pyruvate kinase deficiency. By centralizing the molecular diagnostics of pyruvate kinase deficiency in Utrecht, more care can be provided for the diagnosis, treatment and support of patients.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed2001

Five novel mutations in the gene for human blood coagulation factor V associated with type I factor V deficiency.

Coagulation factor V (FV) plays an important role in maintaining the hemostatic balance in both the formation of thrombin in the procoagulant pathway as well as in the protein C anticoagulant pathway. FV deficiency is a rare bleeding disorder with variable phenotypic expression. Little is known about the molecular basis underlying this disease. This study identified 5 novel mutations associated with FV deficiency in 3 patients with severe FV deficiency but different clinical expression and 2 unaffected carriers. Four mutations led to a premature termination codon either by a nonsense mutation (single-letter amino acid codes): A1102T, K310Term. (FV Amersfoort) and C2491T, Q773Term. (FV Casablanca) or a frameshift: an 8-base pair deletion between nucleotides 1130 and 1139 (FV Seoul(1)) and a 1-base pair deletion between nucleotides 4291 and 4294 (FV Utrecht). One mutation was a novel missense mutation: T1927C, C585R (FV Nijkerk), resulting in the absence of mutant protein despite normal transcription to RNA. Most likely, an arginine at this position disrupts the hydrophobic interior of the FV A2 domain. The sixth detected mutation was a previously reported missense mutation: A5279G, Y1702C (FV Seoul(2)). In all cases, the presence of the mutation was associated with type I FV deficiency. Identifying the molecular basis of mutations underlying this rare coagulation disorder will help to obtain more insight into the mechanisms involved in the variable clinical phenotype of patients with FV deficiency.

Adolescent↗
PubMed2000

Acute intraduodenal bile salt depletion leads to strong gallbladder contraction, altered antroduodenal motility and high plasma motilin levels in humans.

Cholecystokinin is the main hormone involved in postprandial gallbladder contraction. There is also considerable gallbladder contraction in the fasting state, associated with phase III of the gastrointestinal migrating motor complex and release of the hormone motilin. It has been proposed that intraduodenal bile salts exert a negative-feedback control on postprandial cholecystokinin release and resulting gallbladder contraction. We wanted to elucidate whether a similar control mechanism on gallbladder contraction exists in the fasting state. We therefore performed gallbladder ultrasonography and 24-h antroduodenal motility registrations and determined plasma cholecystokinin and motilin levels in six healthy subjects before and after acute (4 g) and chronic (8 days; 8 g day(-1)) oral cholestyramine. Acute cholestyramine strongly decreased gallbladder volumes and increased motilin without changed cholecystokinin levels. There was a negative relationship between gallbladder volumes and plasma motilin levels. Although there was a persistent fasting pattern of antroduodenal motility, its cycle length was increased (P < 0.03) with markedly longer phase II (P < 0. 005). Fasting gallbladder volumes 24 h later were still strongly decreased but gradually increased to pretreatment levels. Before and after 8 days cholestyramine, interdigestive and postprandial gallbladder emptying, intestinal migrating motor complex and hormone levels did not differ. We conclude that acute (but not chronic) intraduodenal bile salt depletion with cholestyramine affects gallbladder and antroduodenal motility, possibly partly related to motilin release.

Adult↗
PubMed1997

Molecular modelling of human red blood cell pyruvate kinase: structural implications of a novel G1091 to a mutation causing severe nonspherocytic hemolytic anemia.

We present a novel G1091 to A mutation in the human liver and red blood cell (RBC) pyruvate kinase (PK) gene causing severe hemolytic anemia. In two families, three children were severely PK-deficient compound heterozygotes exhibiting the G1091 to A mutation and a common G1529 to A mutation on the other allele. In one family, the mother, a G1091 to A heterozygote, later had a second baby with a new husband, also a G1091 to A carrier. The baby was homozygous for the G1091 to A mutation and died 6 weeks after birth from severe hemolysis. Both mutant alleles were expressed at the RNA level. The G1091 to A mutation results in the substitution of a conserved glycine by an aspartate in domain A of RBC PK, whereas the G1529 to A mutation leads to the substitution of a conserved arginine residue with glutamine in the C-domain. Molecular modelling of human RBC PK, based on the crystal structure of cat muscle PK, shows that both mutations are located outside the catalytic site at the interface of domains A and C. The mutations are likely to disrupt the critical conformation of the interface by introducing alternative salt bridges. In this way the Gly364 to Asp and Arg510 to Gln substitutions may cause PK deficiency by influencing the allosteric properties of the enzyme.

Amino Acid Sequence↗
PubMed1997

[Hereditary haemochromatosis: recent developments in diagnostics].

Hereditary haemochromatosis (HHC), a condition of abnormal iron absorption, is among the commonest diseases in humans. Early diagnosis is vital, because the disease is easily treated by phlebotomy to remove iron. Recently, mutations were identified in a HLA-class I-like gene, designated HFE and possibly associated with HHC. It was found that 83% of unselected HHC patients and more than 90% of patients with a clear family history of HHC, were homozygous for a single point mutation resulting in an amino acid substitution (Cysteine282Tyrosine) in the HFE protein. Although these data look compelling, they are not definitive proof that HFE is the haemochromatosis gene, but identification of these mutations will be of value in early diagnosis of haemochromatosis. However, the questions when to use the assay for detection of the Cys282Tyr mutation and how to interpret the results are not fully clear yet. Therefore, caution is still advocated when using molecular testing.

Heart Diseases↗
PubMed1997

Detection of tumour DNA in serum of colorectal cancer patients.

Circulating tumour DNA has previously been detected in serum and plasma of patients with lung cancer and head and neck cancer. These observations could potentially lead to new, specific and non-invasive tools for diagnosis, prognosis and follow-up in neoplastic disease, if found to be a more general phenomenon. To test if tumour DNA is also present in serum of patients with colorectal cancer, we selected 14 colorectal cancer patients with advanced disease. In seven patients, K-ras mutations were detected in the primary tumour, using mutant-specific primers for point mutations in codon 12 or 13 of the K-ras gene. All patients were analysed for mutant DNA in serum. Tumour-specific point mutations, corresponding to the K-ras mutations found in the primary tumour were detected in the serum of all patients but one. No mutant K-ras could be detected in the serum of seven patients without K-ras mutations in the primary tumour. These results may be useful in assessing tumour burden in patients with neoplastic disease. Moreover, consecutive testing of serum tumour DNA after surgery or chemotherapy may be used as a tumour marker for recurrent disease.

Colorectal Neoplasms↗
PubMed1996

Clinical expression of a rare beta-globin gene mutation co-inherited with haemoglobin E-disease.

A single nucleotide substitution and the effect on the phenotype in an Indonesian family with beta-thalassaemia, HbE-trait and HbE-beta-thalassaemia is described. In the proposita (female, age 20 (Hb 7.4 mmol/l; MCV 72 fl; MCH 1.45 fmol; HbA2 3.5%; HbF 2.4%)). An A/G mutation in the RNA cleavage and polyadenylation sequence was detected (AATAAA/AATAGA). Her sister (Hb 8.2 mmol/l; MCV 77 fl; MCH 1.60 fmol; HbA2/HbE 32.4%), carried a different mutation in the beta-globin gene (codon 25; G129/A), and consequently had HbE-trait. Their mother had a haemoglobin concentration of 6.4 mmol/l (MCV 56 fl; MCH 1.20 fmol; HbA2/HbE 55.8%). She was compound heterozygous for the mutation in the poly A-signal and HbE-trait. Using restriction enzyme analysis and linkage studies, we subsequently identified six family members with HbE-beta-thalassaemia, five with beta-thalassaemia and six with HbE-trait. Two individuals were unaffected. The mutation in the polyadenylation sequence causes a mild form of beta (+)-thalassaemia. The MCV and MCH in individuals with both beta-thalassaemia and HbE-trait were significantly lower, yet on average they were only slightly more anaemic than those carrying only the thalassaemic gene.

Adolescent↗
PubMed1995

A distal Sp1-element is necessary for maximal activity of the human gastrin gene promoter.

Studies of transgenic mice have shown that transcriptional control of the gastrin gene exhibits significant species differences. Transfection of the human gastrin promoter in murine cells have depicted proximal Sp1, E-box and CACC elements as the major determinants of transcription. We have examined cis-regulatory elements of the human promoter on a human gastrin expressing cell line and find that a distal -135 to -142 Sp1 element is necessary for maximal activity. Alignment of the mouse and human promoters shows that the proximal human Sp1 and CACC elements are not conserved, whereas the E-box element is retained. The distal Sp1 element is present in mouse but exhibits a C to T transition in the core that is likely to reduce binding affinity of Sp1. We conclude that gastrin gene transcription is regulated by distinct elements in man and rodents.

Adenocarcinoma↗
PubMed1993

Splice site mutation in the human protein C gene associated with venous thrombosis: demonstration of exon skipping by ectopic transcript analysis.

Heterozygosity for a G-->C mutation converting the highly conserved Gln184 (CAG) to His (CAC) was identified at the last nucleotide of exon 7 of the protein C gene in two family members with deep vein thrombosis. As the nucleotide is a part of the 5 splice site of intron G, it was examined how the mutation affected splicing of protein C pre-mRNA. Relevant protein C cDNA fragments were amplified with polymerase chain reaction after reverse transcription of ectopic mRNA from peripheral blood lymphocytes. Southern blot analysis and nucleotide sequencing of these fragments showed a fragment (A) corresponding to correctly spliced mRNA originating from the normal allele and a fragment (B) corresponding to a truncated mRNA lacking exon 7, originating from the mutant allele. A third fragment (C) lacking exons 7 and 8 was identified in both affected and unaffected family members, as well as in normal controls. Analysis of human liver protein C mRNA indicated that the ectopic lymphocyte mRNA was qualitatively representative for the tissue-specific mRNA. In conclusion, evidence is provided showing that the mutation abolishes formation of correctly spliced mRNA. This agrees with the observation that the mutation results in a type 1 protein C deficiency.

Adult↗
PubMed1993

Ovarian cancers express and process progastrin.

Gastrin synthesis in ovarian tumors has been described in a few isolated cases associated with the Zollinger-Ellison syndrome. Consequently, ovarian gastrin synthesis has been considered exceptional. In order to evaluate whether expression of gastrin in ovarian tumors indeed is rare, we examined the expression and processing of progastrin in 16 malignant and 5 benign ovarian tumors and 4 normal postmenopausal ovaria. Using a library of sequence specific radioimmunoassays, cleavage by processing-like enzymes, and gel chromatography, we found that one-half of the malignant tumors expressed significant concentrations of amidated gastrins [6.7 +/- 2.7 (SEM) pmol/g; range, 1.4-20.0 pmol/g, n = 7]. The concentrations of glycine-extended gastrins and progastrins were low (0.25 +/- 0.03 and 1.4 +/- 0.4 pmol/g, respectively) but higher than in controls and benign tumors. Chromatography showed that the majority of the bioactive gastrins was unsulfated gastrin-17. The other half of the malignant tumors expressed glycine-extended gastrins and progastrins (0.2 +/- 0.03 and 0.6 +/- 0.1 pmol/g; n = 9), but the amidation of the peptides was impaired (0.1 +/- 0.03 pmol/g). Low concentrations of glycine-extended gastrins and progastrins were detected in the normal ovarian tissues (0.2 +/- 0.05 pmol/g tissue and 0.2 +/- 0.06 pmol/g, respectively, n = 4) and in the benign tumors (0.1 +/- 0.02 pmol/g and 0.5 +/- 0.03 pmol/g; n = 5). Amidated gastrins were undetectable, except in low amounts in a single benign tumor (0.2 pmol/g tissue). The results show that postmenopausal ovaria and neoplastic ovarian tissues express the gastrin gene at peptide level. The synthesis and processing of progastrin increase considerably in malignant tumors.

Cholecystokinin↗
PubMed1992

Co-transcription of the gastrin and cholecystokinin genes with selective translation of gastrin mRNA in a human gastric carcinoma cell line.

So far, no cells have been found to synthesize both of the homologous hormones, cholecystokinin and gastrin. Northern analysis and reverse transcription PCR showed, that the human gastric carcinoma cell line (AGS) expresses both a gastrin mRNA of 0.7 kb and a cholecystokinin transcript of 0.8 kb. A library of sequence-specific radioimmunoassays, cleavage with processing-like enzymes and chromatography subsequently revealed that the gastrin mRNA was translated into progastrin that was constitutively secreted into the medium (45 +/- 3 pmol/l). Neither procholecystokinin nor any of its processing products were detectable in cells and media. The results suggest that differentiation into gastrin- or cholecystokinin-producing cells may be regulated at the translational level. The gastric cell line, AGS, provides a model for studies of translational regulation of cell differentiation.

Blotting, Northern↗
PubMed1990

Radioimmunoassay for sequence 38-54 of human progastrin: increased diagnostic specificity of gastrin-cell diseases.

Antisera were raised against fragment 38-54 of human progastrin. All of eight immunized rabbits responded, but only one (No. 2145) produced high-titer (3.2 x 10(4)) and high-avidity (Keff degrees = 1.2 x 10(12) l/mol) antibodies. A radioimmunoassay based on antiserum 2145 and monoiodinated gastrin-34 was specific for the N-terminal sequence of human gastrin-34. It measured concentrations of 9.7 +/- 1, 18.4 +/- 2 pmol/l (mean +/- SEM) and 1.553 (0.7-476) nmol/l (median (range], respectively, in sera from normal subjects (n = 20), patients with duodenal ulcer (n = 19), and Zollinger-Ellison patients (n = 8). Conventionally measured concentrations of carboxyamidated gastrins in the same sera were 21.4 +/- 1, 23.8 +/- 3 pmol/l (mean +/- SEM) and 0.833 (0.4-214) nmol/l (median (range)), respectively. The results show that radioimmunoassays specific for the N-terminus of human gastrin-34 discriminate between healthy subjects and patients with duodenal ulcer. The improved diagnostic specificity is due to co-measurement of unprocessed and partly processed progastrins that occur in plasma of patients with duodenal ulcer disease and gastrinomas. We suggest that conventional gastrin assays are supplemented with assays specific for the N-terminus of gastrin-34 in studies of duodenal ulcer disease.

Amino Acid Sequence↗
PubMed1990

Gastrin, cholecystokinin and their precursors in acoustic neuromas.

Using sequence-specific radioimmunoassays the occurrence of 4 neuropeptides (cholecystokinin (CCK), gastrin, somatostatin, substance P and some of their precursors) was examined in 19 human acoustic nerve tumors and corresponding normal tissue. The normal acoustic nerve tissue obtained by autopsy contained traces of CCK, somatostatin, and substance P (less than or equal to 0.5 pmol/g), but neither proCCK, gastrin nor progastrin. In contrast 8 tumors expressed proCCK (range 0.2-4.5 pmol/g), 3 tumors gastrin (0.1-7.3 pmol/g) and 14 tumors progastrin (0.6-2.2 pmol/g). Traces of somatostatin were present in two and substance P in one tumor. The results show that acoustic neuromas often express the homologous CCK and gastrin genes, but process their propeptides poorly to transmitter-active peptides. The tumor synthesis of gastrin/progastrin contrasts to the rare, sporadic expression of the gastrin gene in normal nerve tissue.

Adult↗