Baillière's clinical endocrinology and metabolism, Jul 1, 1995
The identification of RET proto-oncogene mutations in patients with MEN2 2 years ago was a waters... more The identification of RET proto-oncogene mutations in patients with MEN2 2 years ago was a watershed event in the management of this genetic cancer syndrome. The identification of a finite number of mutations that together causes more than 95% of hereditary and 15-25% of sporadic MTC has made it possible to develop simple and definitive tests to screen individuals at risk for this tumour syndrome. The impact of this technology is enormous. It is now possible to reassure 50% of family members at risk that they, and their children, do not have to worry about developing MTC. In the other 50% who are gene carriers, it is now possible to approach clinical management with greater certainty and plot strategies that are likely to result in a greater percentage of curative therapy. It seems likely that this technology will also have an impact on the management of sporadic MTC, although it is still too early to define a specific role for mutational analysis in these patients, except to exclude hereditary disease. The identification of specific mutations causative for MTC makes it possible to conceive future strategies for the treatment or prevention of MTC and to further extend the impact of these exciting findings.
Familial persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a glucose metabolism disor... more Familial persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a glucose metabolism disorder in neonates characterized by inappropriate insulin secretion in the presence of profound hypoglycemia. Loss of function mutations in the sulfonylurea receptor (SUR) gene recently have been implicated as a cause for familial PHHI in nine independent families. This review will describe the combined positional cloning and candidate gene strategy used to identify the SUR gene as the one responsible for PHHI. Potential roles for SUR in other disorders of insulin secretion remains to be determined.
Untreated hyperthyroidism in pregnant women is associated with a high incidence of maternal and f... more Untreated hyperthyroidism in pregnant women is associated with a high incidence of maternal and fetal complications. Thus, its treatment is mandatory, ideally using PTU because it has lesser transplacental passage. From 1987 and 1991 we have attended 19 hyperthyroid pregnant women. Of these, 18 had diffuse and 1 nodular goiter and in 10, thyrotoxicosis preceded pregnancy. PTU was used in 17 women (7 received it along the whole pregnancy), five had to be operated due to poor response, one received propranolol and one patient was not treated due to lack of attendance. Cesarean section was performed in 12 women, 5 had vaginal delivery, one had a miscarriage at the 20th week of pregnancy due to a neurological malformation and one patient was lost from control before delivery. The newborn of the untreated woman had a neonatal thyrotoxicosis and the resting 16 did not show evidence of thyroid disfunction. Newborns from mothers receiving PTU until delivery had significantly lower rT3 levels and non significant changes in T4 and T3. At the end of the observation period, 8 patients were euthyroid, 3 hypothyroid (2 after 131-l and 1 after surgery), 4 continued on PTU and 4 were lost from control. It is concluded that the outcome of pregnancy may be uneventful in hyperthyroid women provided that there is a close and adequate follow up.
Multiple endocrine neoplasias (MEN) are syndromes inherited as autosomal dominant. The applicatio... more Multiple endocrine neoplasias (MEN) are syndromes inherited as autosomal dominant. The application of the techniques of molecular biology has made possible the identification of the genes causing MEN 1 and 2. The gene responsable for MEN 1 belongs to the family of ...
Best Practice & Research Clinical Endocrinology & Metabolism, Jun 1, 2010
Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant cancer syndrome with major c... more Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant cancer syndrome with major components of medullary thyroid carcinoma (MTC), pheochromocytoma and hyperparathyroidism. The disease is caused by germline mutations of the RET proto-oncogene. Subtypes of MEN 2 include MEN 2A, MEN 2B and familial MTC (FMTC) which differ in pattern of additional lesions or--in FMTC--lack of pheochromocytoma. In 2009, after extensive review of the literature, the guidelines of the American Thyroid Association made several recommendations regarding clinical and genetic diagnostic testing and treatment options. In this article, the recently published literature is reviewed and concerns regarding future perspectives are added. In particular, a critical handling of rare DNA variants and double mutations is necessary. Up to now, mutation-specific risk profiles and mutation-associated treatment recommendations are unavailable. We emphasise the need for approved centres for treatment of patients affected by MEN 2, not only adults but young children as well. As a high level of skill is required for endoscopic adrenal-sparing surgery, surgeons should declare their expertise before operating such patients. Registry-based follow-up should be mandatory including documentation of short- and long-term outcome in order to provide valid data for future counselling of patients with MEN 2.
The spontaneous expression of Class II molecules (HLA-DR) was studied in cultured thyrocytes obta... more The spontaneous expression of Class II molecules (HLA-DR) was studied in cultured thyrocytes obtained from patients with Graves Disease (n = 7), Hashimoto's Thyroiditis (n = 5), euthyroid nodular goiter, (n = 12), papillary carcinoma (n = 5), and laryngeal carcinoma (3 normal thyroid glands). If nodular goiters and papillary carcinoma are of autoimmune origin, as Graves Disease and Hashimoto's Thyroiditis, they should spontaneously express HLA-DR antigen on their cell surface as this has been considered one of the initial steps of autoimmunity. The study was performed using the cytotoxicity assay. Immediately after the thyroid glands were obtained, thyrocytes were labelled with 51-Cr and incubated overnight; the cells were destroyed by adding monoclonal antiHLA-DR antibody and rabbit complement. The cytotoxicity index (CI% + SD) which reflects 51-Cr release from lyzed cells was used to measure antigen expression. While Graves Disease's and Hashimoto's Disease's thyrocytes expressed HLA-DR in high proportion, normal thyrocytes and thyroid cells from other diseases did so in minimal proportion (28.12 +/- 10.71 vs 2.26 +/- 2.32, p < 0.001). These findings strongly suggest that nodular goiters and papillary carcinoma are not of autoimmune origin since they are unable to express HLA-DR on their cell surface. It is postulated that HLA-DR expression is the result of the influence of T lymphocytes previously sensitized to thyroid antigens.
The purpose of this paper is to study some of the mechanisms by which antigen presentation, one o... more The purpose of this paper is to study some of the mechanisms by which antigen presentation, one of the first steps in the immune process, is modulated. Three different experiments are performed: a) Using thyroid tissue from patients operated on for Graves' Disease, spontaneous HLA-DR and TPO antigen expressions were measured through the Cytotoxicity Assay; these findings were correlated with the presence of antiTPO in the sera of these patients. It was found that only patients whose thyroid tissue spontaneously expressed both antigens had circulating antiTPO in their sera, thus demonstrating that dual expression is basic for antibody production. b) Blood samples from other Graves' patients were obtained; peripheral lymphocytes were isolated and cultured in complete media for 5 days, then supernatant was separated and IFN-g concentration was measured by a sandwich type RIA; the same procedure was done in 12 normal controls in order to compare the results. It was found that lymphocytes from Graves' patients secreted significantly more IFN-g than normal controls (20.9 +/- 13.54 U/ml vs 3.7 +/- 3.22 U/ml respectively, p < 0.001) confirming that they were sensitized, so this determination could be used as a marker of immune process, if other infectious conditions are excluded; also it was found that IFN-g hypersecretion persists once hyperthyroidism has been treated, pointing out that the immune abnormality is still present.(ABSTRACT TRUNCATED AT 250 WORDS)
In order to measure TSH receptor antibodies (TRAb) we tried to set up a radioreceptor assay using... more In order to measure TSH receptor antibodies (TRAb) we tried to set up a radioreceptor assay using human thyroid membranes. Due to lack of appropriate binding activity of the material obtained, we decided to use a kit which provides solubilized porcine membrane-receptors to TSH instead of human membranes, as well as calibrators that have been standardized in a receptor assay against MRC LATS std B. With these reactives we have measured TRAb in sera from 7 normal controls (C), 54 thyrotoxic patients (43 diffuse goiters [BDH], 8 multinodular goiters [BHM] and 3 Subacute Thyroiditis [TSA]), 3 patients with Hashimoto's Thyroiditis (TH) and in 6 non-hyperthyroid Graves ophthalmopathy patients. Measurement were initially performed using calibrators and the results expressed as U/L; since a very good correlation between the expression U/L and the calculated Inhibition Index (I.I.) was found (r = 0.99, n = 15, p < 0.001), results are shown using latter. In C mean +/- SD value for I.I. was 3.4 +/- 2.37%, so we decided to use, as cut off criteria for differentiating between normal and abnormal results, the figure 11%, which represents the mean +/- 3 SD. According to this, 93% of BDH had elevated TRAb activity while only slightly more than one third of MBH had elevated values, this difference being highly significant (p < 0.0001); both TSA and TH patients showed low TRAb activity while all Graves ophthalmopathy pts had elevated values, thus suggesting that they had a latent disease. We concluded that the methodology that is adequate and practical for clinical purposes.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this work was to study if TSH has a role in TPO antigen expression in vivo. Using ... more The purpose of this work was to study if TSH has a role in TPO antigen expression in vivo. Using the cytotoxicity assay we measured TPO expression and correlated it with TSH serum levels in 3 groups of rats: control, hypothyroid and hypothyroid supplemented with thyroxine. For comparative purposes, in the cytotoxicity assay we used rat monoclonal antiTPO or human sera with high titles for antiTPO antibodies. Hypothyroid rats showed marked elevations of TSH serum levels and TPO antigen expression in their thyrocytes when compared to the control and supplemented group. A positive correlation between TPO antigen and TSH levels was observed (r = 0.69, p < 0.001). There was an excellent correlation between TPO results using rat monoclonal or human sera antibodies (r = 0.94 p < 0.0001). It is concluded that TSH modulates TPO antigen expression. These data are of clinical relevance considering that TSH modulates the expression of other antigens that can maintain the immune response and perpetuate the immune disease in patients with Graves disease treated with antithyroid drugs. Thus, the avoidance of TSH hypersecretion with administration of thyroxine could be useful to treat these patients.
Baillière's clinical endocrinology and metabolism, Jul 1, 1995
The identification of RET proto-oncogene mutations in patients with MEN2 2 years ago was a waters... more The identification of RET proto-oncogene mutations in patients with MEN2 2 years ago was a watershed event in the management of this genetic cancer syndrome. The identification of a finite number of mutations that together causes more than 95% of hereditary and 15-25% of sporadic MTC has made it possible to develop simple and definitive tests to screen individuals at risk for this tumour syndrome. The impact of this technology is enormous. It is now possible to reassure 50% of family members at risk that they, and their children, do not have to worry about developing MTC. In the other 50% who are gene carriers, it is now possible to approach clinical management with greater certainty and plot strategies that are likely to result in a greater percentage of curative therapy. It seems likely that this technology will also have an impact on the management of sporadic MTC, although it is still too early to define a specific role for mutational analysis in these patients, except to exclude hereditary disease. The identification of specific mutations causative for MTC makes it possible to conceive future strategies for the treatment or prevention of MTC and to further extend the impact of these exciting findings.
Familial persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a glucose metabolism disor... more Familial persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a glucose metabolism disorder in neonates characterized by inappropriate insulin secretion in the presence of profound hypoglycemia. Loss of function mutations in the sulfonylurea receptor (SUR) gene recently have been implicated as a cause for familial PHHI in nine independent families. This review will describe the combined positional cloning and candidate gene strategy used to identify the SUR gene as the one responsible for PHHI. Potential roles for SUR in other disorders of insulin secretion remains to be determined.
Untreated hyperthyroidism in pregnant women is associated with a high incidence of maternal and f... more Untreated hyperthyroidism in pregnant women is associated with a high incidence of maternal and fetal complications. Thus, its treatment is mandatory, ideally using PTU because it has lesser transplacental passage. From 1987 and 1991 we have attended 19 hyperthyroid pregnant women. Of these, 18 had diffuse and 1 nodular goiter and in 10, thyrotoxicosis preceded pregnancy. PTU was used in 17 women (7 received it along the whole pregnancy), five had to be operated due to poor response, one received propranolol and one patient was not treated due to lack of attendance. Cesarean section was performed in 12 women, 5 had vaginal delivery, one had a miscarriage at the 20th week of pregnancy due to a neurological malformation and one patient was lost from control before delivery. The newborn of the untreated woman had a neonatal thyrotoxicosis and the resting 16 did not show evidence of thyroid disfunction. Newborns from mothers receiving PTU until delivery had significantly lower rT3 levels and non significant changes in T4 and T3. At the end of the observation period, 8 patients were euthyroid, 3 hypothyroid (2 after 131-l and 1 after surgery), 4 continued on PTU and 4 were lost from control. It is concluded that the outcome of pregnancy may be uneventful in hyperthyroid women provided that there is a close and adequate follow up.
Multiple endocrine neoplasias (MEN) are syndromes inherited as autosomal dominant. The applicatio... more Multiple endocrine neoplasias (MEN) are syndromes inherited as autosomal dominant. The application of the techniques of molecular biology has made possible the identification of the genes causing MEN 1 and 2. The gene responsable for MEN 1 belongs to the family of ...
Best Practice & Research Clinical Endocrinology & Metabolism, Jun 1, 2010
Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant cancer syndrome with major c... more Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant cancer syndrome with major components of medullary thyroid carcinoma (MTC), pheochromocytoma and hyperparathyroidism. The disease is caused by germline mutations of the RET proto-oncogene. Subtypes of MEN 2 include MEN 2A, MEN 2B and familial MTC (FMTC) which differ in pattern of additional lesions or--in FMTC--lack of pheochromocytoma. In 2009, after extensive review of the literature, the guidelines of the American Thyroid Association made several recommendations regarding clinical and genetic diagnostic testing and treatment options. In this article, the recently published literature is reviewed and concerns regarding future perspectives are added. In particular, a critical handling of rare DNA variants and double mutations is necessary. Up to now, mutation-specific risk profiles and mutation-associated treatment recommendations are unavailable. We emphasise the need for approved centres for treatment of patients affected by MEN 2, not only adults but young children as well. As a high level of skill is required for endoscopic adrenal-sparing surgery, surgeons should declare their expertise before operating such patients. Registry-based follow-up should be mandatory including documentation of short- and long-term outcome in order to provide valid data for future counselling of patients with MEN 2.
The spontaneous expression of Class II molecules (HLA-DR) was studied in cultured thyrocytes obta... more The spontaneous expression of Class II molecules (HLA-DR) was studied in cultured thyrocytes obtained from patients with Graves Disease (n = 7), Hashimoto's Thyroiditis (n = 5), euthyroid nodular goiter, (n = 12), papillary carcinoma (n = 5), and laryngeal carcinoma (3 normal thyroid glands). If nodular goiters and papillary carcinoma are of autoimmune origin, as Graves Disease and Hashimoto's Thyroiditis, they should spontaneously express HLA-DR antigen on their cell surface as this has been considered one of the initial steps of autoimmunity. The study was performed using the cytotoxicity assay. Immediately after the thyroid glands were obtained, thyrocytes were labelled with 51-Cr and incubated overnight; the cells were destroyed by adding monoclonal antiHLA-DR antibody and rabbit complement. The cytotoxicity index (CI% + SD) which reflects 51-Cr release from lyzed cells was used to measure antigen expression. While Graves Disease's and Hashimoto's Disease's thyrocytes expressed HLA-DR in high proportion, normal thyrocytes and thyroid cells from other diseases did so in minimal proportion (28.12 +/- 10.71 vs 2.26 +/- 2.32, p < 0.001). These findings strongly suggest that nodular goiters and papillary carcinoma are not of autoimmune origin since they are unable to express HLA-DR on their cell surface. It is postulated that HLA-DR expression is the result of the influence of T lymphocytes previously sensitized to thyroid antigens.
The purpose of this paper is to study some of the mechanisms by which antigen presentation, one o... more The purpose of this paper is to study some of the mechanisms by which antigen presentation, one of the first steps in the immune process, is modulated. Three different experiments are performed: a) Using thyroid tissue from patients operated on for Graves' Disease, spontaneous HLA-DR and TPO antigen expressions were measured through the Cytotoxicity Assay; these findings were correlated with the presence of antiTPO in the sera of these patients. It was found that only patients whose thyroid tissue spontaneously expressed both antigens had circulating antiTPO in their sera, thus demonstrating that dual expression is basic for antibody production. b) Blood samples from other Graves' patients were obtained; peripheral lymphocytes were isolated and cultured in complete media for 5 days, then supernatant was separated and IFN-g concentration was measured by a sandwich type RIA; the same procedure was done in 12 normal controls in order to compare the results. It was found that lymphocytes from Graves' patients secreted significantly more IFN-g than normal controls (20.9 +/- 13.54 U/ml vs 3.7 +/- 3.22 U/ml respectively, p < 0.001) confirming that they were sensitized, so this determination could be used as a marker of immune process, if other infectious conditions are excluded; also it was found that IFN-g hypersecretion persists once hyperthyroidism has been treated, pointing out that the immune abnormality is still present.(ABSTRACT TRUNCATED AT 250 WORDS)
In order to measure TSH receptor antibodies (TRAb) we tried to set up a radioreceptor assay using... more In order to measure TSH receptor antibodies (TRAb) we tried to set up a radioreceptor assay using human thyroid membranes. Due to lack of appropriate binding activity of the material obtained, we decided to use a kit which provides solubilized porcine membrane-receptors to TSH instead of human membranes, as well as calibrators that have been standardized in a receptor assay against MRC LATS std B. With these reactives we have measured TRAb in sera from 7 normal controls (C), 54 thyrotoxic patients (43 diffuse goiters [BDH], 8 multinodular goiters [BHM] and 3 Subacute Thyroiditis [TSA]), 3 patients with Hashimoto's Thyroiditis (TH) and in 6 non-hyperthyroid Graves ophthalmopathy patients. Measurement were initially performed using calibrators and the results expressed as U/L; since a very good correlation between the expression U/L and the calculated Inhibition Index (I.I.) was found (r = 0.99, n = 15, p < 0.001), results are shown using latter. In C mean +/- SD value for I.I. was 3.4 +/- 2.37%, so we decided to use, as cut off criteria for differentiating between normal and abnormal results, the figure 11%, which represents the mean +/- 3 SD. According to this, 93% of BDH had elevated TRAb activity while only slightly more than one third of MBH had elevated values, this difference being highly significant (p < 0.0001); both TSA and TH patients showed low TRAb activity while all Graves ophthalmopathy pts had elevated values, thus suggesting that they had a latent disease. We concluded that the methodology that is adequate and practical for clinical purposes.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this work was to study if TSH has a role in TPO antigen expression in vivo. Using ... more The purpose of this work was to study if TSH has a role in TPO antigen expression in vivo. Using the cytotoxicity assay we measured TPO expression and correlated it with TSH serum levels in 3 groups of rats: control, hypothyroid and hypothyroid supplemented with thyroxine. For comparative purposes, in the cytotoxicity assay we used rat monoclonal antiTPO or human sera with high titles for antiTPO antibodies. Hypothyroid rats showed marked elevations of TSH serum levels and TPO antigen expression in their thyrocytes when compared to the control and supplemented group. A positive correlation between TPO antigen and TSH levels was observed (r = 0.69, p < 0.001). There was an excellent correlation between TPO results using rat monoclonal or human sera antibodies (r = 0.94 p < 0.0001). It is concluded that TSH modulates TPO antigen expression. These data are of clinical relevance considering that TSH modulates the expression of other antigens that can maintain the immune response and perpetuate the immune disease in patients with Graves disease treated with antithyroid drugs. Thus, the avoidance of TSH hypersecretion with administration of thyroxine could be useful to treat these patients.
Uploads
Papers by Nelson Wohllk