Metabolic syndrome X--high risk factor for acute myocardial infarction and its complications.

Metabolic Syndrome X is a clinical entity which comprises the following factors: diabetes mellitus, arterial hypertension, high levels of triglyceride and/or low levels of HDL cholesterol, central obesity and microalbuminuria (by WHO criteria). The first goal of this study was to determine the frequency of the Metabolic Syndrome X (MSX) in patients with acute myocardial infarction compared with the general population. The second goal of the study was to examine the frequency of heart failure and reinfarction rate in the patients with myocardial infarction, with and without MSX. Furthermore, the relationship between gender and MSX was analyzed. A total of 101 patients with acute myocardial infarction took part in randomized trial (32 women and 69 men). MSX and all of its components were diagnosed according to WHO criteria. To determine statistical significance of our results, we used chi2 test and t-test for independent samples. From 101 patient 48 had MSX (47.52%), while in the general population incidence of MSX is 3-4%. The reinfarction and the heart failure rate were significantly higher in the group of patients with MSX (p = 0.0067 and p = 0.0217, respectively). To conclude, the results of the present study confirm that MSX is a high risk factor for myocardial infarction and its complications.

Insulin-like growth factor family in malignant haemangiopericytomas: the expression and role of insulin-like growth factor I receptor.

Haemangiopericytoma is a rare soft tissue tumour originating from the contractile pericapillary cells. Relatively little is known about its molecular pathogenesis. To address this issue, the insulin-like growth factor family (IGFs) was analysed in 19 tumours collected from a human tumour bank network. Seven of the tumours were associated with severe hypoglycaemia. Of these, six were retroperitoneal and one was located in the leg. 3 out of the 19 tumours (15.8 per cent) were positive for insulin-like growth factor I (IGF I) mRNA and 11 were positive for IGF II mRNA (57.9 per cent). Almost 90 per cent of haemangiopericytomas expressed IGF I receptor (IGF IR) mRNA (17 out of 19), five (26.3 per cent) expressed IGF binding protein 1 (IGF BP1), three (15.8 per cent) expressed IGF BP2, and four (21 per cent) exhibited IGF BP3 mRNA. All of the 14 haemangiopericytomas examined with regard to specific receptor binding were IGF IR positive, ranging from 1.2 to 16.2 per cent. Binding was much higher in IGF I/IGF IR positive tumours (15.3+/-0. 7) than in IGF I negative/IGF IR positive tumours (5.1+/-3.3). The potential role of IGF IR as a growth promoting factor in malignant haemangiopericytoma was studied using antisense oligonucleotides and monoclonal antibody alphaIR3 that specifically inhibit IGF IR synthesis or activity. 10 microM IGF IR antisense oligonucleotides significantly inhibited the growth of haemangiopericytoma cells in culture, by around 50 per cent; monoclonal antibody against IGF IR (alphaIR3) also significantly inhibited proliferation. The data suggest that IGF IR may play an important role in the genesis and progression of malignant haemangiopericytomas.

The expression and role of insulin-like growth factor II in malignant hemangiopericytomas.

Hemangiopericytoma is a rare soft tissue tumor originating from contractile pericapillary pericytes. To address the issue of molecular genetic events that participate in genesis and progression of hemangiopericytoma we analyzed insulin-like growth factor (IGF) II and IGF I receptor in 29 tumors collected from a human tumor bank network. Seven of these tumors were associated with severe hypoglycemia; six were retroperitoneal and one was located in the leg. Of 22 tumors tested 12 (54.5%) exhibited IGF II mRNA, while almost 90% (17 of 19) of hemangiopericytomas exhibited IGF I receptor mRNA. Sera from some patients whose tumors expressed IGF II mRNA contained elevated levels of IGF II. Removal of the tumor eliminated most of the IGF II immunoreactivity from the sera. The potential role of IGF II as a growth-promoting factor was examined on three malignant primary hemangiopericytoma cell cultures. Extracellular addition of IGF II significantly enhanced cell proliferation in a dose-dependent manner. Antisense oligodeoxynucleotides that specifically inhibit IGF II mRNA, at a concentration of 40 or 80 micrograms/ml, inhibited the growth of hemangiopericytoma cells significantly, by 40%. Simultaneous administration of antisense deoxyoligonucleotides to both IGF II and IGF I receptor inhibited tumor cell proliferation by even 80%. Our data suggest that tumor cells produce IGF II, and that this in turn stimulates their proliferation by autocrine mechanisms.

Molecular pathology of hemangiopericytomas accompanied by severe hypoglycemia: oncogenes, tumor-suppressor genes and the insulin-like growth factor family.

Relatively little is known about molecular genetic events that participate in the genesis and progression of hemangiopericytoma. In this study, we describe two cases of hemangiopericytoma accompanied by severe hypoglycemia. Tumor cells from patient 1 exhibited insulin-growth factor I (IGF I) and insulin-like growth factor I receptor (IGF IR) mRNA transcripts. Tumor cells from patient 2 exhibited IGF II, IGF IR and IGF binding proteins 1-3 mRNA. Serum from patient 2 contained IGF II, mostly in a large molecular form ("big" IGF II); the IGF II level did not change after the tumor removal. The presence of IGF IR in tumor cells was confirmed by immunoprecipitation with antibodies that recognize human IGF IR subunit (visualized as a 460-kDa band). The hemangiopericytoma cells derived from patient 1 expressed 210000 IGF I receptors/cell. Specific binding of IGF I to the tumor cell membrane fraction was higher in tissue from patient 1, while the tissue of patient 2 showed relatively low IGF I binding. In contrast, IGF II binding was much higher in tissue from patient 2. Both tumor tissues showed positive immunostaining for c-Jun; one tumor showed strong immunostaining for c-Myc, H-Ras and p53, while the other exhibited strong reaction with H-Ras antibodies only. No loss of the heterozygosity at the genes APC, NFI and nm23-H1 loci in tumor tissue obtained from patient 1 was found. In effect, our results suggest multiple molecular genetic changes in hemangiopericytoma -- activation of some oncogenes and the IGF growth factor family. IGF ligands together with IGF IR could be responsible for hypoglycemia and perhaps the transformed phenotype.

[National consensus on hyperandrogenemia]. / Nacionalni konsenzus o hiperandrogenemiji.

Croatian Endocrine Society and Croatian Academy of Medical Sciences organized Symposium on Hyperandrogenaemia on March 22nd, 1996. Different aspects of this syndrome were discussed: epidemiology, classification and clinical features, steroid biosynthesis in the adrenal gland and ovarium, the genetics of polycystic ovarian syndrome (PCOS), clinical significance of testosterone and dihydrotestosterone metabolism, androgen excess and metabolic syndrome (syndrome X), insulin disturbances in PCOS, increased risk for development of non insulin dependent diabetes mellitus, androgen effects on serum lipoproteins, insulin like growth factors and function of ovarium, Doppler parameters in PCOS, treatment of hyperandrogenaemia, skin changes in PCOS, tests for adrenal and ovarial function, arterial hypertension and hyperinsulinism. National Board of Hyperandrogenaemia has been elected.

Molecular genetics of malignant insulinoma.

Malignant insulinoma is an rare form of cancer with poor prognosis and a reported 5-year survival of 35%. Relatively little is known about the etiology of this disease or of the oncogenes and tumor suppressor genes that participate in its genesis and progression. To address this issue, several protooncogenes, including K-ras, N-ras, erbB-2, erbB-3,c-myc, c-fos, c-jun were examined. Also analyzed was the expression of the growth factors TGF-alpha, EGF, and insulin as well as the EGF receptor (EGF-R), p53 and the putative anti-metastasis gene nm23-H1. These were examined in malignant insulinomas, benign insulinomas, pancreatic B cell hyperplasias and in normal endocrine pancreas. Normal endocrine pancreas showed moderate immunoreaction for c-myc and a strong reaction for insulin. All other parameters were negative. Benign pancreatic B cell hyperplasias were slightly or moderately positive for N-ras and TGF-alpha, and were weakly positive for EGF-R. They were strongly positive for c-myc and insulin. In malignant insulinomas there was strong immunoreaction for c-myc, TGF-alpha, N-ras, K-ras and p53. Insulin reaction was moderate or strong. Molecular genetic studies have been performed for the presence of activating point mutations in codon 12 of the c-K-ras oncogene. Mutations were detected using primer-mediated, mutant-enriched, polymerase chain reaction-restriction fragment length polymorphism analysis and were further characterized by allele-specific oligonucleotide hybridization. Four out of six patients with malignant insulinoma and two out of eight patients with benign insulinoma harbored K-ras point mutations at codon 12. All patients with mutated K-ras oncogene also had elevated levels of p53 protein as well as c-myc and TGF-alpha. In one extremely malignant case we found concomitant mutation at codon 12 of K-ras and codon 61 of the N-ras gene. Our data are consistent with the idea that malignant progression is accompanied by the progressive accumulation of multiple genetic lesions and suggest that activation of myc, TGF-alpha and ras genes may be early events in the development of insulinoma.

[Androgen excess in women and the metabolic syndrome (syndrome X)]. / Suvisak androgena u zena i metabolicki sindrom (sindrom X).

In this paper we presented characteristics of insulin resistance syndrome (IRS), also known as metabolic syndrome and syndrome X, with an emphasis on insulin resistance in hyperandrogenemic women. The aim features of IRS are obesity, hypertension, dyslipidemia-hypertriglyceridemia and decreased HDL cholesterol, impaired glucose tolerance with hyperinsulinemia and higher cardiovascular morbidity. It is considered typical that in hyperandrogenemia, especially in PCO syndrome, insulin resistance and hyperinsulinemia without other characteristics of IRS are expressed.

Multiple genetic alterations in malignant metastatic insulinomas.

Proto-oncogenes, growth factors/receptors, and tumour suppressor genes were analysed in malignant metastatic insulinomas. Normal pancreas showed only a moderate immunoreaction for c-myc proto-oncogene and a strong reaction for insulin. Benign insulinomas were slightly or moderately positive for transforming growth factor alpha (TGF alpha), weakly positive for epidermal growth factor receptor (EGF-R), and strongly positive for c-myc and insulin. In malignant insulinomas, besides a strong immunoreaction for c-myc and TGF alpha, activation of c-K-ras and overexpression of p53 protein were found. Insulin reaction was moderate or strong. Three out of six malignant insulinomas displayed a c-K-ras point mutation at codon 12. All mutations were guanine to cytosine transversion, resulting in amino acid substitution, glycine to arginine. Mutations were present in metastatic insulinomas only. Patients with mutated c-K-ras oncogene had overexpression of p53 protein as well as c-myc and TGF alpha overexpression. Our results support the view that malignant progression is a consequence of more than one genetic lesion and suggest that activation of myc, TGF alpha an ras genes plays a role in a multistep process of tumour progression, perhaps serving as an initiating event.

The role of insulin-related substance in Hodgkin's disease.

An insulin-related growth-promoting substance was detected in the serum of a patient with Hodgkin's disease who suffered from severe hypoglycaemia, as well as in the supernatant of homogenized spleen tissue of the same patient. Low concentrations of this substance enhanced DNA synthesis of short-term-cultured spleen tumour cells obtained from the same patient, while the addition of anti-insulin antiserum interfered with that effect. Moreover, the preincubation of this insulin-related substance with the anti-insulin antiserum abrogated its stimulatory effect on tumour cell proliferation. Both insulin and the insulin-related substance bound to patients splenocytes to a similar extent. The data suggest that the insulin-related substance, found in this particular case of Hodgkin's disease, plays a role in tumour progression by an autocrine mechanism.

Autocrine tumour growth regulation by somatomedin C: an in-vitro model.

A human primary haemangiosarcoma was derived from a patient with severe hypoglycaemia. Cell line established from that tumour secreted somatomedin C in serum-free culture media. Immunoreactive somatomedin from the media eluted from Sephacryl S-200 in two peaks of 160 000 and 8000 molecular weights. Similar results were obtained when medium was acidified and chromatographed on Sephadex G-50. Binding of tracer concentrations of 125I-labelled somatomedin C to human haemangiosarcoma cells was much higher than that of 125I-labelled insulin. Half-maximal displacement of 125I-labelled somatomedin C binding occurred at an unlabelled somatomedin C concentration of 0.7 nmol/l. Insulin competed with 125I-labelled somatomedin for binding to this receptor, but 150-fold more insulin was required for half-maximal displacement. Somatomedin secreted by human haemangiosarcoma cells and purified from serum-free media strongly stimulated [methyl-3H]thymidine incorporation into the DNA of these cells. Inhibition of somatomedin C secretion by cortisol resulted in the inhibition of tumour cell proliferation but stimulation of somatomedin secretion by human GH stimulated the cell proliferation rate. It appears that production of somatomedin C in human haemangiosarcoma cells plays a part in the regulation of tumour growth by an autocrine mechanism.

Syndrome of inappropriate secretion of anti-diuretic hormone (SIADH) produced by an adenocarcinoma of the colon. Report of one case.

It is described a patient with all classical features of SIADH, and elevated levels of urinary ADH which was most probably produced by a colon carcinoma. It is proposed that all indistinct hyponatremias be thoroughly analysed and that urinary ADH be tentatively considered as a tumor marker for colon carcinoma.