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C J Lips

Publications and source records attributed to C J Lips.

At least 109 records · Page 6Linked to original sources
PubMed1991

Non-linkage of the islet amyloid polypeptide gene with type 2 (non-insulin-dependent) diabetes mellitus.

Type 2 (non-insulin-dependent) diabetes is associated with the deposition of islet amyloid. The major formative peptide, islet amyloid polypeptide, has recently been characterised and an abnormality of the structure or expression of this gene is a possible candidate for the inherited component of Type 2 diabetes. A restriction fragment length polymorphism of the gene has been identified with Pvu II. To study the relationship between the islet amyloid polypeptide gene and Type 2 diabetes, two distinct genetic approaches have been undertaken. Firstly, non-linkage has been demonstrated in four pedigrees, with four normoglycaemic first degree relatives having an allele associated with diabetes in other family members, and one affected relative not having the putatively associated allele. The LOD score taking age-related penetrance into account was -1.68, making linkage unlikely (p = 0.02). Secondly, in a population-based restriction fragment length polymorphism survey, no linkage disequilibrium of the alleles was found between a population of unrelated Caucasian subjects with Type 2 diabetes and a normal population. A mutation in or near the islet amyloid polypeptide gene is thus unlikely to be a common cause of Type 2 diabetes.

Amyloid↗
PubMed1991

Stimulation and suppression of intact parathyroid hormone (PTH1-84) in normal subjects and hyperparathyroid patients.

OBJECTIVE: Because of an overlap between serum PTH values in healthy controls and hyperparathyroid patients we sought to evaluate a short stimulation and suppression test for differentiating the two groups. SUBJECTS: Subjects were 34 patients with primary hyperparathyroidism (PHPT) and 25 healthy controls. DESIGN: After stimulation with intravenous EDTA (10 mg/kg body weight in 5 minutes) blood samples were obtained for up to 15 minutes. After an oral calcium dose of 1 g, blood samples were obtained at 1 and 2 hours. After an intravenous calcium dose (2.5 mg/kg body weight in 30 seconds), blood samples were obtained serially for 20 minutes. MEASUREMENT: Serum PTH(1-84) was measured by a double antibody technique. RESULTS: The intravenous EDTA test resulted in an average 2.6-fold increase of serum PTH(1-84) in hyperparathyroid patients, whereas it increased 10.5-fold in controls. A response was absent in three of 23 patients. There was an overlap in results between patients with mild hyperparathyroidism and controls. The oral calcium dose decreased serum PTH(1-84) in patients to 0.73 and in controls to 0.55 of the basal value, but six of 15 patients and two of 12 controls did not respond. The intravenous calcium test resulted in a drop of serum PTH(1-84) in hyperparathyroid patients to 0.51 and in control subjects to 0.40 of the basal value, and non-responders were not observed. There was a strong correlation between the responses to the EDTA and the calcium infusion tests in the patients (r = 0.97, P less than 0.01). Fasting serum calcium and serum PTH(1-84) showed a positive correlation in PHPT patients (r = 0.75, P less than 0.001) and a negative correlation in control subjects (r = -0.41, P less than 0.05). Based on these relationships, hyperparathyroid patients and controls could be completely separated. CONCLUSION: The wide range of responses to stimulation and suppression tests and the correlation between these responses in hyperparathyroid patients indicate various degrees of autonomy. As the response to these tests is less marked in patients than in controls and both groups still overlap, these tests are not useful for the diagnosis of primary hyperparathyroidism.

Adolescent↗
PubMed1991

Hybridohistochemical demonstration of alternative splicing of the CALC-I gene.

Precursor RNA is processed to mature mRNA by excision of the noncoding introns. This process is called splicing and usually is studied by in vitro transcription experiments and by Northern blotting. The pre-mRNA of the first calcitonin gene (CALC-I) can be spliced alternatively into two different mRNAs encoding either for calcitonin or for calcitonin gene-related peptide (alpha-CGRP). The expression of CALC-I was studied by in situ hybridization in the nervous system of the rat with calcitonin-specific and CGRP-specific probes. We found evidence for alternative splicing of the pre-mRNA of CALC-I in the motor neurons of the spinal cord. alpha-CGRP mRNA was found in the nuclei and the cytoplasm of the spinal motor neurons, whereas hybridization with a calcitonin-specific probe was located strictly in the nuclei. Because no calcitonin RNA and protein was detected in the cytoplasm of the cells, we concluded that the hybridization obtained in the nucleus was the pre-mRNA encoding for alpha-CGRP.

Animals↗
PubMed1991

No effect of the long-acting somatostatin analogue octreotide in patients with insulinoma.

The efficacy of subchronic (3 weeks) treatment with the long-acting somatostatin analogue octreotide was studied in four patients with symptomatic benign insulinoma. No clinical or biochemical effect on serum glucose, insulin, C-peptide or glucagon was observed in all four patients despite clearly detectable serum levels of octreotide. The resistance to octreotide therapy in these patients might be explained by the absence of somatostatin analogue receptors on their tumours.

Adolescent↗
PubMed1990

Islet amyloid polypeptide: structure and upstream sequences of the IAPP gene in rat and man.

Islet amyloid polypeptide (IAPP) or amylin is a pancreatic islet hormone which was first found in amyloid in insulinomas and in pancreases of patients with type 2 diabetes. In rat a similar polypeptide occurs; however, pancreatic amyloid in this species has not been described. Here we report the structure of the rat and human IAPP gene. Both consist of three exons and two introns which are very similar. The upstream sequence of the rat IAPP gene contains a TATA-box, a CCAAT-sequence and a GT-element, whereas the upstream sequence of the human IAPP gene contains a TATA-box and a rat insulin enhancer-like sequence. This suggests that the rat and human IAPP gene may be controlled differently at the transcriptional level.

Amyloid↗
PubMed1990

Insulin-like growth factor gene expression in human smooth muscle tumors.

A role for insulin-like growth factors (IGF) in autocrine or paracrine growth stimulation of tumor cells has been proposed for tumors of different origins. We have studied IGF gene expression in human uterus smooth muscle (myometrium) and in a panel of benign (leiomyoma) and malignant (leiomyosarcoma) smooth muscle tumors. Using RNA transfer blot analysis we could demonstrate that in smooth muscle tissue and tumors IGF genes are differentially expressed. The mRNA species detected had the same size as reported for IGF mRNAs from other tissues. However, the abundance of the IGF gene transcripts varied from tissue to tissue. The amounts of IGF mRNAs detected in smooth muscle tumors were compared to the levels found in normal smooth muscle. The IGF-I gene was expressed at high levels in normal myometrium and in leiomyomas but appears to be repressed in leiomyosarcomas. Also the IGF-I peptide was detected in myometrium and in leiomyomas, but in leiomyosarcomas the level was substantially lower. The IGF-II gene was expressed at low levels in normal myometrium and leiomyomas but is activated in leiomyosarcomas. With increasing malignancy from the two major IGF-II mRNA species, 6.0 and 4.8 kilobases, in particular the 6.0-kilobase mRNA is produced at higher levels. In conclusion, these data suggest that for IGF-I a role in tumor cell growth is not likely, but probably IGF-II is involved in malignant smooth muscle tumor growth progression.

Female↗
PubMed1990

IAPP/amylin gene transcriptional control region: evidence for negative regulation.

Aberrant expression of the islet amyloid polypeptide (IAPP) gene might be involved in the pathogenesis of non-insulin-dependent diabetes mellitus (NIDDM). Here, we report that IAPP promoter-luciferase constructs revealed tissue-specific activity. This activity was not mediated by cAMP. Sequential 5' deletions of the IAPP promoter caused a progressive derepression of the IAPP gene promoter in IAPP-producing cells. Comparison of the nucleotide sequence of the IAPP promoter with that of the insulin promoter (both active in pancreatic beta-cells) reveals two sequence elements of putative importance: an insulin enhancer-like sequence and an element which corresponds to a protected domain in rat insulin I gene promoter footprint experiments.

Amyloid↗
PubMed1990

[Pseudohypoparathyroidism; where is the hitch?].

Pseudohypoparathyroidism is a condition in which for some reason the normal effect of PTH in the target organ fails to occur. In the Ia type here described the signal transmission is impaired due to abnormal genetic development of the stimulating G protein (Gs) in the cell membrane resulting in insufficient cAMP production after binding of PTH on the membrane receptor. The failure to occur of the normal PTH effect impairs the calcium homeostasis. In many cases this type of pseudohypoparathyroidism is associated with phenotypical characteristics such as short stature, round face, obesity, brachydactyly, subcutaneous and intracerebral calcifications and sometimes bradyphrenia. Since the Gs protein aspecifically also brings about production of cAMP after binding of other polypeptide hormones to this hormone-specific receptor, several hormone resistances may be present concurrently.

Adult↗
PubMed1990

Transfection of calcitonin gene regulatory elements into a cell culture model of the C cell.

Calcitonin gene expression in the TT cell line can be regulated by phorbol esters, cAMP, glucocorticoids, and 1,25-dihydroxyvitamin D3. To further study the regulation of this gene we have sequenced 1460 bases 5' to the start of calcitonin gene transcription. This DNA sequence contains cis consensus elements for both phorbol ester- and cAMP-responsive elements. To study the role of these elements, calcitonin 5' flanking DNA was coupled to the human growth hormone gene as a reporter and transiently transfected into TT cells, a human thyroid C cell line. Treatment of transfected TT cells stimulated a two- to fivefold increase in reported gene product expression, confirming the existence of functional cAMP- and phorbol ester-dependent enhancers within the calcitonin 5' flanking sequence.

Animals↗
PubMed1990

Expression of insulin-like growth factor 1 in sarcomas.

The expression of insulin-like growth factor-1 (IGF-1) was studied in normal tissues, in eight benign lesions and in 50 sarcomas. In palmar fibromatosis the spindle cells in cell-dense areas exhibited a strong immunoreactivity. IGF-1 was variably found in leiomyosarcomas (7/8), malignant schwannomas (7/9), synovial sarcomas (2/3), liposarcomas (3/6), fibrosarcomas (1/3), malignant fibrous histiocytomas (10/18) and in one angiosarcoma. Two rhabdomyosarcomas failed to express IGF-1 and only the spindle cell component of synovial sarcomas was positive. Immunoreactivity for IGF-1 in 10 malignant filrous histiocytomas (MFH) appeared to be related to co-expression of smooth muscle actin. These findings imply that MFHs can be subdivided into a group of tumours which are devoid of morphological and immunophenotypic evidence of differentiation and a group which manifest immunophenotypic differentiation.

Actins↗
PubMed1990

Detection of calcitonin-encoding mRNA by radioactive and non-radioactive in situ hybridization: improved colorimetric detection and cellular localization of mRNA in thyroid sections.

The localization of mRNA encoding calcitonin was studied by in situ hybridization using 35S-labeled RNA probes and biotin-labeled DNA probes. Radiolabeled probes were detected by autoradiography and biotin-labeled probes by streptavidin-biotin-peroxidase. To intensify the colorimetric signal, the indirect avidin-biotin complex (ABC) method was performed. However, the results were often variable. To improve the sensitivity, the peroxidase reaction signal was enhanced with a gold-silver deposit intensification reaction. To shorten the incubation times and to enhance the colorimetric reaction, several reaction steps were performed in a microwave oven. The localization of calcitonin mRNA in thyroid tissue, as detected with in situ hybridization, was confirmed by immunohistochemical localization of the calcitonin polypeptide. The results of in situ hybridization using biotinylated probes were compared to in situ hybridization using radioactive probes. Our data show that the results of in situ hybridization applied on frozen and paraffin-embedded sections using biotinylated DNA probes, detected with an indirect streptavidin-biotin-peroxidase reaction and intensified by silver-gold enhancement, were comparable to those obtained with radioactive probes. The localization of calcitonin encoding mRNA was in agreement with the localization of the calcitonin polypeptide.

Affinity Labels↗
PubMed1990

Insulinomas in MEN-I patients: early detection and treatment of insulinomas in patients with the multiple endocrine neoplasia syndrome type-I.

In the multiple endocrine neoplasia syndrome type I (MEN-I syndrome), periodic screening of patients and their close relatives may improve prognosis and life expectancy. Although there is diffuse involvement of the pancreas with microadenomatosis, insulinomas in the MEN-I syndrome usually occur as single tumours. This is illustrated here by two patients with insulinomas and the MEN-I syndrome. Preoperative localization of the tumours was achieved accurately by digital subtraction angiography combined with dynamic computerized tomography after a bolus injection of contrast medium. At present, two and three years after elective surgery both patients are asymptomatic. The early detection and treatment of insulinomas is extremely important because of the high risk of cerebral damage associated with late diagnosis. Periodic investigation of MEN-I family members can promote the early diagnosis and treatment of insulinomas, especially in young patients, whose life expectancy and quality of life may be improved.

Adolescent↗
PubMed1989

The complete islet amyloid polypeptide precursor is encoded by two exons.

Islet amyloid polypeptide (IAPP) is the 37-amino acid peptide subunit of amyloid found in pancreatic islets of type 2 diabetic patients and in insulinomas. Recently, we isolated the human gene encoding IAPP [(1988) FEBS Lett. 239, 227-232]. We now report the nucleotide sequences of a human insulinoma cDNA encoding a complete IAPP precursor, and of the corresponding parts of the IAPP gene. Two exons, which are approx. 5 kb apart in the human genome, encode the 89-amino acid pre-pro-IAPP. At least one additional exon is present further upstream in the IAPP gene. A putative signal sequence at the amino-terminus of the precursor suggests that IAPP is a secreted protein.

Amino Acid Sequence↗
PubMed1989

Development of multiple endocrine neoplasia type 2A does not involve substantial deletions of chromosome 10.

In MEN2A both familial and sporadic cases are known. The familial cases show a dominant pattern of inheritance. In these respects, MEN2A resembles other tumors in whose etiology so-called tumor suppressor genes play a decisive role. The MEN2A locus has been assigned to chromosome 10 by linkage studies. Analysis of tumor DNA from 42 patients shows that markers on chromosome 10 were lost in only one tumor. Thus, these results contrast with previous studies which show that tumor development is generally associated with the loss of the whole or substantial parts of the chromosome on which the putative tumor suppressor gene is located.

Carcinoma↗
PubMed1989

Pheochromocytoma-induced hypertensive encephalopathy revealing MEN-IIa syndrome in a 13-year old boy. Implications for screening procedures and surgery.

In the multiple endocrine neoplasia (MEN) type II syndrome, pheochromocytomas become manifest at a later age than medullary thyroid carcinomas (MTC) do. The present report concerns a 13-year-old boy, belonging to a MEN-IIA kindred, who was admitted because of convulsive seizures related to hypertensive encephalopathy. A pheochromocytoma was suspected immediately and appropriate medical therapy was initiated. A right adrenal pheochromocytoma was removed, as well as a pheochromocytoma of an accessory right adrenal gland. Today, three years later our patient is still asymptomatic and the results of the thyroid C-cell provocative tests remain normal. This case clearly justifies the conclusion that periodic investigation of MEN-II family members to detect both medullary thyroid carcinoma and pheochromocytoma should begin early in life, as the latter may be the initial life-threatening expression of the disease. Long-term follow-up of patients treated with unilateral adrenalectomy will permit better definition of the risk of contralateral recurrence in such cases.

Adolescent↗
PubMed1989

Screening for the multiple endocrine neoplasia syndrome type I. A study of 11 kindreds in The Netherlands.

Since 1974, a total of 11 families with the multiple endocrine neoplasia syndrome type I (MEN-I), including 52 patients, were identified. Fifteen of these 52 patients died of MEN-I-related complications (mean age, 44 years), most of them in the period before screening was started. In 11 of the 15 patients, death was caused by complicated peptic ulcer disease, in 2 by metastasis of an endocrine pancreatic tumor, and in 2 by renal failure due to hyperparathyroidism. Family screening led to the diagnosis of 43 new endocrine lesions: 21 cases of hyperparathyroidism, 16 endocrine pancreatic tumors, and 6 pituitary tumors. Hyperparathyroidism either was the first manifestation of MEN-I or was diagnosed simultaneously with the other components of the syndrome in 44 (94%) of the 47 patients who underwent full evaluation.

Adolescent↗