Screening of six risk exons of the RET proto-oncogene in families with medullary thyroid carcinoma in the Czech Republic.

Medullary thyroid carcinoma (MTC) occurs as a sporadic form (75%) or as an autosomal dominant inherited familial disorder (25%) called familial MTC (FMTC) or as multiple endocrine neoplasia type 2 (MEN2) syndromes. Germ-line mutations in the rearranged during transfection (RET) proto-oncogene in exons 10, 11, 13, 14, 15 and 16 are known to be a cause of most of the familial forms. In this paper we report molecular genetic testing of 106 families with MTC (358 tested persons) from the Czech Republic in which we directly sequenced these six exons of the RET proto-oncogene. We detected germ-line mutations in 100% of MEN2B families (4/4 families), 90% of MEN2A families (9/10), 40% of FMTC families (4/10) and 7% of apparently sporadic MTC (6/82). Eleven different germ-line mutations were revealed. MEN2B was associated with mutation Met918 Thr in exon 16. In one MEN2B family beside this mutation the Tyr791 Phe was also found, which has not yet been reported. MEN2A was restricted to different mutations in exon 11 (codon 634). In FMTC and 'sporadic' MTC families the mutations in exons 10, 11, 13 and 14 were detected. The genotype/phenotype correlations are given. Genetic testing revealed germ-line mutations in 23 index patients, 24 family members and excluded them in 53 relatives.

[Ret proto-oncogene mutation found in the Czech population and its predictive value for offspring of patients with medullary carcinoma of the thyroid gland]. / Mutace nalezené v Ret protoonkogenu v ceské populaci a jejich prediktivní prínos pro potomky pacientu s medulárním karcinomem stítné zlázy.

The authors completed a total of 23 pedigrees with the clinical diagnosis of medullary thyroid carcinoma (5 MEN 2A pedigrees, 11 FMTC pedigrees and 7 MTC pedigrees). Using the method of polymerase chain reaction (PCR), it was possible to define the rate of the most frequent mutations in exons 10, 11 and 16 of Ret-protooncogene present in the Czech population. The most frequent hereditary mutation found in MEN 2A and FMTC groups is substitution of thymine for cytosine in position 2095 of the transmembranous domain of the Ret-tyrosine kinase gene. Another six types of known mutations were tested.

[The effect of gender on prevalence and survival in thyroid carcinoma]. / Vliv pohlaví na prevalenci a prezití karcinomu stítné zlázy.

Based on their own experience with a large group of patients with thyroid cancers, the authors confirm the higher prevalence of differentiated thyroid cancers both papillary and follicular (1 : 3,5) in females, while the differences in anaplastic and medullary cancers are much less prominent. Survival of females in univariate studies is much higher in both papillary and follicular cancers compared to males, in multivariate studies these differences lose their significance and only in papillary cancers under the age of 40 years at diagnosis and in a subgroup of papillofollicular cancers the differences retain their significance. The authors therefore deduce that differences found in univariate studies are significantly influenced by other factors such as age at the diagnosis and the spread of disease at the diagnosis.

[Changes in bone metabolism in girls with Turner's syndrome]. / Zmeny kostního metabolismu u dívek s Turnerovým syndromem.

BACKGROUND: Data of the prevalence of osteoporosis in girls with Turner's syndrome are not uniform, and its causes have not been fully elucidated. Information on the mineralization of osseous tissue is controversial. The objective of the present work was to examine some more recent indicators of bone metabolism in a group of girls with Turner's syndrome. METHODS AND RESULTS: A group of girls aged 4-20 years was examined where genetic examination had revealed karyotype 45 X (7 patients) or mosaic 45 X (46 XX) (9 patients). On X-ray examination osteoporosis was found in 71%, densitometric evidence of reduced bone density was provided in 2% of the examined patients. As to biochemical osteologically oriented examinations, a significantly reduced osteocalcin value was found (1.18 +/- 0.42 mug/l, as compared with 11.38 +/- 0.03 in controls, p < 0.001), reduced values of alkaline phosphatase (2.67 mukat/l as compared with 8.46 +/- 4.16 mukat/l in controls, p < 0.005) and reduced values of the bone isoenzyme of alkaline phosphatase (1.47 mukat/l as compared with 6.04 +/- 0.27 in controls, p < 0.001). The values of calcemia (2.63 / 0.13 mmol/l) and phosphataemia (1.36 +/- 0.25 mmol/l) did not differ significantly from values recorded in controls. To six patients the authors administered for a period of three months 1,25(OH)2D3, 0.25 mg on alternate days. The osteocalcin values rose to 5.27 +/- 3.14 micrograms/l, similarly as alkaline phosphatase (6.32 +/- 1.83 mukat/l) and the bone isoenzyme of alkaline phosphatase (2.42 +/- 1.95 mukat/l), not evaluated statistically because of the small number of patients. CONCLUSIONS: In girl with Turner's syndrome a reduced bone density was revealed in 25%, reduced values of osteocalcin, alkaline phosphatase and its bone isoenzyme indicate a reduced osteoblast activity. It appears that administration of 1,25(OH)2D3 can have a favourable effect.

Osteocalcin in congenital adrenal hyperplasia.

Osteocalcin in the serum reflects bone turnover. It is known that prolonged therapy with glucocorticoids inhibits bone turnover. The aim of this study was to evaluate the osteocalcin level in children with congenital adrenal hyperplasia treated by glucocorticoids and mineralocorticoids and to assess the influence of 1,25(OH)2D3. The subjects were 75 children with congenital adrenal hyperplasia, aged 1-18 years, treated with glucocorticoids and mineralocorticoids in substitution doses from birth. These children demonstrated low levels of osteocalcin and alkaline phosphatase, whereas calcium and phosphate were in the normal ranges. Despite these abnormalities, no osteoporosis was detectable and a normal growth rate was confirmed, most probably because of higher levels of androgens; 17-OH progesterone averaged 11.8 nmol/l. After treatment with 1,25(OH)2D3, the osteocalcin levels increased, followed later by increases of alkaline phosphatase and bone isoenzyme.

[Use of immunoreactive calcitonin and sonography in the diagnosis of medullary carcinoma of the thyroid gland]. / Vyuzití imunoreaktivního kalcitoninu a sonografie v diagnostice medulárního karcinomu stítné zlázy.

In a group of 94 patients with a histologically verified medullary thyroid carcinoma were 59 patients with the sporadic form and 35 patients with the familial form. After radical surgery and subsequent actinotherapy in all patients the values of immunoreactive calcitonin were monitored along with the sonographic examination. In all with calcified thyroid residues confirmed on sonography, or when metastases were detected in the liver, elevated or high levels of immunoreactive calcitonin were found. The authors emphasize the importance of this examination for the early detection of relapses of medullary thyroid carcinoma.

Chromosome sensitivity to bleomycin in patients with dominantly inherited and sporadic tumors.

G2 chromosomal sensitivity to bleomycin (30 micrograms/ml) was tested in PHA-stimulated lymphocytes of healthy subjects and in patients with familial and sporadic tumors. These were multiple endocrine neoplasias (MEN) types 1, 2A and 2B, familial medullar thyroid cancer, Recklinghausen neurofibromatosis type I, sporadic and hereditary malignant tumors, and a preleukemic disorder, the myelodysplastic syndrome. Control subjects were either young (15-20), middle-aged (28-49) or old (70-83 years). Cells from old healthy subjects and from subjects with MEN 1 showed increased sensitivity to clastogenic effects of bleomycin. All the remaining investigated groups were insignificantly different from controls. Our data suggest that in contrast with recessively inherited syndromes with chromosome instability the mutagen hypersensitivity, as evaluated by the extent of chromosomal damage, is not a feature of most dominantly inherited tumor syndromes.

[Multiple endocrine neoplasia type 2: familial variant of medullary carcinoma of the thyroid gland]. / Mnohocetná endokrinní neoplazie typu 2: familiární varianta medulárního karcinomu stítné zlázy.

In addition to a brief characteristic of the syndrome of multiple endocrine neoplasia type 2 and medullary thyroid carcinoma with a familial incidence which is a prerequisite of the syndrome, the authors submit an account on a group of 53 patients who were on the authors' records during the past 12 years. During this period the disease is systematically searched for in the families of newly diagnosed patients by examining the immunoreactive calcitonin level of relatives. Familial variants account for 28% of all medullary thyroid carcinomas. Patients who are on the records so far belong to 24 families. Approximately twice as often an isolated variant of the familial type of medullary carcinoma is involved, as compared with association with another endocrine affection, in particular pheochromocytoma (Sipple's syndrome), but associated forms will increase in number perspectively (multiple endocrine neoplasia 2A). The syndrome of multiple endocrine neoplasia 2B is very malignant but in view of the typical phenotype the disease should be diagnosed already before the change to malignancy--once the disease develops into the clinical stage the course is very adverse. From the original number of all familial tumours 38 subjects survive (72%), incl 22 who were subjected to bilateral total thyroidectomy based on screening in the preclinical stage. The prognosis of these individuals is very favourable, the calcitonin levels are throughout the follow-up period (2-10 years) repeatedly negative. With regard to the possible association with another endocrinopathy (pheochromocytoma or hyperparathyroidism) all must be followed up systematically (screening) with regard to the manifestation of an associated endocrinopathy frequently only after a longer time interval.

[Medullary carcinoma of the thyroid gland. Personal experience]. / Medulárni karcinom stitné zlázy. Vlastni zkusenosti.

The authors present their experience with the diagnosis and treatment of medullary thyroid carcinoma (MTC) in a group of 175 patients in the records of the RI in Motol. From the above number 106 are alive, 69 of the patients who died were diagnosed at the time of the clinical manifestation of the disease, frequently an advanced stage of the disease. Of the living patients one third was treated by total thyroidectomy after active screening. MTC accounts under our conditions in recent years for 8.6% of all thyroid malignancies. The familial variant with autosomal dominant heredity accounts for 26.5% of the above number. Within the framework of the familial variant the most frequent finding is non-MEN MTC, only 30% MTC are part of the MEN 2A or MEN 2B syndromes. MTC in childhood belongs practically always to the familial variant. At present the authors' group comprises 13 children and adolescents under 18 years, incl. one boy with the MEN 2B syndrome who succumbed to the disease. In 8 children based on active screening total thyroidectomy was indicated, incl. 5 patients were by histological examination only hyperplasia of the C-cells, i.e. a precancerous condition, was detected. After operation repeatedly in all these patients the level of immunoreactive calcitonin is low which indicates an excellent prognosis. The authors draw attention to the importance of active screening in families of all direct relations of the patient where MTC was diagnosed. Complete removal of thyroid tissue at the time of hyperplasia of C-cells or the presence of tumourous microfoci has a marked positive effect on the subsequent fate of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Medullary carcinoma of the thyroid gland and the APUD system]. / Medulární karcinom stítné zlázy a APUD systém.

Medullary thyroid carcinoma, MTC, accounts for 8-10% of all thyroid malignancies. It occurs in the sporadic form (70-75%) and the familial variant (25-30%). In familial MTC the autosomal dominant type of heredity is involved. This variant is found frequently in association with other endocrine hyperplasias or tumours within the framework of the APUD system and is thus an indispensible condition of the MEN 2 syndrome, either MEN 2A (MTC and pheochromocytoma and/or hyperparathyroidism) or MEN 2B with the frequent concurrent presence of pheochromocytoma and a typical phenotype, in particular multiple neurofibromas on the lips and tongue. The type of MTC determines also to a certain extent the prognosis of the disease. MTC in the framework of MEN 2A are usually most benign, while the prognosis is poorest for MEN 2B. The sporadic variant has a poorer prognosis, as compared with differentiated thyroid carcinoma. The only effective and rational treatment of MTC is radical surgery. In all instances where we confirm the diagnosis before surgery we indicate bilateral total thyroidectomy. In the familial variant where the tumour is usually multifocal and in both lobes this indication is absolute, in sporadic forms with possible early intrathyroid dissemination of the primary tumour also to the other side, bilateral surgery is also indicated. Moreover we know that a certain ratio of assumed sporadic forms are genetically conditioned tumours and thus are familial. The histological finding of hyperplasia of the C-cells suggests the familial variant even when tumourous transformation did not occur yet.(ABSTRACT TRUNCATED AT 250 WORDS)

[Determination of serum calcitonin using a non-commercial RIA method]. / Stanovení kalcitoninu v séru nekomercní RIA metodou.

A radioimmunoanalytical determination of the immunoreactive calcitonine in the humen serum was worked out using the authors' own specific antiserum, the preparation and properties of which are reported in the present paper. The precision and reliability of the analytical procedure is within the usual limits (the intraserial variation coefficient was 8.6%, the calculated sensitivity was 6 pg/ml). The reported procedure was employed to determine calcitonine in a larger number of patients who were examined because of suspected medullar carcinoma of the thyroid gland and in patients suffering from other thyropathies. The results are discussed from the viewpoint of heterogeneity of calcitonine in the circulation.

[Diagnostic significance of osteocalcin levels in the classification of senile osteoporosis]. / Diagnostický význam hladiny osteokalcinu pri klasifikaci starecké osteoporózy.

The authors investigated the osteocalcin (BGP) serum level in 55 women with the senile type of osteoporosis. According to BGP values they divided the group into three sub-groups. Lower values were recorded in 27 subjects (50%), normal values comparable with a control group of 13 healthy women of equal age were recorded in 21 subjects (38%) and in a small sub-group of 7 women (12%) the BGP level was raised or high. Senile osteoporosis can be also heterogeneous, characterized by a reduced, normal but in some also an elevated metabolic turnover of bone. It is, however, possible that this is a question of different stages and at the time of examination the mentioned status was recorded. An opportunity to examine BGP levels would be a great asset for osteological departments, among others also for the classification of osteoporosis with regard to the rate of the metabolic turnover or remodelling activity and would provide doctors with valuable information for decision taking on rational therapy.

[Present experience with surgical treatment of medullary carcinoma of the thyroid gland]. / Nase soucasné zkusenosti s chirurgickou lécbou medulárního karcinomu stítné zlázy.

Between June 1 1975 and Dec. 31 1989 at the surgical clinic for adults in Prague-Motol 44 patients were operated on account of medullary cancer of the thyroid gland (MCT). In the great majority total thyroidectomy (TTE) was performed which in this disease is an absolute indication. In some instances the operation was supplemented by lymphadenectomy. The prognosis of the familial type of the disease was more favourable due to the possibility of active screening of the tumour. The authors reached the conclusion that the therapeutic results in MCT can be improved by early diagnosis as well as sufficiently radical surgical operations.

Application of non-commercial methods for estimation of immunoreactive serum calcitonin in clinical practice (comparison of two methods).

The authors compared the results of two radioimmunological methods for the estimation of immunoreactive calcitonin in human serum. Parallel with the commercial RIA kit the estimation was made by the authors' own modification of this process with their own specific antiserum and radioligand prepared in the laboratory. The results in a large group of patients with medullary carcinoma of the thyroid gland (MCT) in different stages of the disease revealed that although the values obtained by the two methods differ, there is a statistically significant correlation between the values and the clinical evaluation is also comparable.

[Osteocalcin]. / Osteokalcin.

Osteocalcin, non-collagenous vitamin K dependent bone protein is as a biochemical indicator of osteoblastic activity and metabolic turnover in bone, valuable in the diagnosis of several diseases and in investigations of the dynamics of osseous changes (processes) during treatment of osteopathies. Elevated osteocalcin levels are normal in childhood and adolescence. In the diurnal rhythm the peak is recorded in the early hours. Pathologically elevated values are associated with primary hyperparathyroidism, Paget's disease, chronic renal failure, acromegaly and some malignities. A rise in women during the early postmenopausal period signalizes an enhanced metabolic turnover of bone in those women who are candidates of postmenopausal osteoporosis. Low levels are as a rule recorded in advanced age, in nanism, hypoparathyroidism, type 1 diabetes, rheumatoid arthritis, vitamin D deficiency, vitamin K deficiency, hypercorticalism and glucocorticoid treatment.

[The effect of streptozotocin-induced diabetes treated with insulin on the metabolism of calcium, magnesium and phosphorus]. / Vliv streptozotocinového diabetu léceného inzulínem na metabolismus vápníku, horcíku a fosforu.

In a group of rats with streptozotocin induced diabetes the excretion of calcium, magnesium, phosphorus and creatinine in urine was investigated and the calcium, magnesium and phosphorus content of bone in relation to the duration of the disease. The authors observed that in diabetic rats the urinary losses of calcium, magnesium and phosphorus increase significantly. The creatinine excretion is also significant but lower in relation to calciuria and therefore the value of Nordin's index in diabetic rats rises markedly. Bone of diabetic rats in the early stage of diabetes (32 days) loses magnesium, while the calcium and phosphorus content does not change significantly. During longer persistence of severe diabetes (70 days) a significant drop of all three minerals in bone was observed. The bones of diabetic animals on the 70th experimental day were macroscopically smaller and were very fragile. The authors' findings suggest a marked influence of streptozotocin diabetes on calcium phosphate metabolism and bone metabolism, in particular on account of STZ diabetes, on an early drop of magnesium in bone. The possible impact of this finding for clinical practice will have to be tested further.

Plasma somatostatin activity in medullary cancer of the thyroid.

In a group consisting of 50 adults and 5 children with diagnosed or suspected medullary cancer of the thyroid, plasma somatostatin levels were measured in 77 samples with a sensitive radioimmunoassay. Only 2 patients had clearly enhanced plasma somatostatin immunoreactivity, both with highly active aggressive tumors. Other patients had plasma somatostatin levels of under 20 ng/l or undetectable ones. No evidence of response of somatostatin levels to pentagastrin stimulation was found.