Safety, efficacy and steroid-sparing effect of amifampridine in Lambert-Eaton myasthenic syndrome patients - real world data.

INTRODUCTION: Lambert-Eaton myasthenic syndrome (LEMS) is an ultrarare neuromuscular disease with a triad of symptoms: muscle paresis, dysautonomy, and areflexia. Amifampridine is the symptomatic treatment of LEMS. AIM OF STUDY: To assess the effectiveness and safety of treatment in the real world. MATERIAL AND METHODS: 14 patients with non-neoplastic LEMS treated with amifampridine were enrolled in the study (female 42.9%, mean age 48.8 ± 11.4 years). The patients were assessed using the Quantitative Myasthenia Gravis (QMG) scale, QMG limb domain (LD) score, spirometry, Hand Grip Strength (GRIP) test, and repetitive nerve stimulation study (RNS) at baseline and at the end of follow-up. Diagnostic delay since first symptoms was from seven months up to 22 years. Treatment delay ranged from one to 26 years. The patients were treated and reevaluated after 21.1 ± 12.0 weeks (range 13-48). RESULTS: All of the patients improved in QMG score. Mean improvement was 5.1 ± 2.0 (range 1-8) points (p < 0.001) and this showed no correlation with the duration of the disease before treatment (p = 0.477). 85.7% of patients (N = 12) improved ≥ 3 points (clinically meaningful) in QMG. 78.6% of the patients improved in QMG LD (mean 2.2 ± 1.6 points (p < 0.001)). Also, forced vital capacity (FVC) improved after treatment (p = 0.031). Mean improvement in GRIP test was 7.0 ± 7.1 kg in the right hand and 5.2 ± 7.5 kg in the left hand (p < 0.001). In RNS before treatment, facilitation ( > 100%) was observed in 78.6% (N = 11) of patients, and was higher before treatment (p < 0.001). Compound muscle action potential (CMAP) amplitude was higher after treatment (p < 0.001). Mean increase of CMAP amplitude was 2.1 ± 1.6 times. In 64.3% (N = 9) of patients lowering of corticosteroid dose was achieved. CONCLUSIONS: Amifampridine is an effective treatment in non-neoplastic LEMS patients, regardless of disease duration. The treatment is well-tolerated and allows to reduce dose of corticosteroids in the majority of patients.

Apoptosis Evaluation in Circulating CD34+-Enriched Hematopoietic Stem and Progenitor Cells in Patients with Abnormally Increased Production of Endogenous Glucocorticoids in Course of Cushing's Syndrome.

Abnormalities in hematological parameters of peripheral blood have been noted in patients with endogenous Cushing's Syndrome (CS) in the corticotropin (ACTH)-dependent and ACTH-independent forms. Nevertheless, the exact mechanism of glucocorticoids (GCs) action on human hematopoiesis is still not entirely clear. The aim of the study was to determine whether endogenous excessive production of GCs could affect apoptosis of CD34+ cells enriched in hematopoietic stem and progenitor cells (HSPCs) collected from the peripheral blood of newly diagnosed CS patients. Flow cytometry, Annexin-V enzyme-linked immunosorbent assay, TUNEL assay, real-time quantitative PCR, and microarray RNA/miRNA techniques were used to characterize CS patients' HSPCs. We found that the glucocorticoid receptor (GR) protein expression levels in CS were higher than in healthy controls. A complex analysis of apoptotic status of CS patients' HSPC cells showed that GCs significantly augmented apoptosis in peripheral blood-derived CD34+ cells and results obtained using different methods to detect early and late apoptosis in analyzed cell population were consistent. CS was also associated with significant upregulation in several members of the BCL-2 superfamily and other genes associated with apoptosis control. Furthermore, global gene expression analysis revealed significantly higher expression of genes associated with programmed cell death control in HSPCs from CS patients. These findings suggest that human endogenous GCs have a direct pro-apoptotic activity in hematopoietic CD34+ cells derived from CS subjects before treatment.

Rare clinical manifestation of multiple endocrine neoplasia type 1.

OBJECTIVE: Multiple endocrine neoplasia type 1 (MEN1) is a rare disorder characterized by tumors in various endocrine glands. It is caused by a mutation in the MEN1 gene. This gene encodes menin, a protein that regulates cell proliferation. The clinical manifestation of the syndrome most commonly involves hyperparathyroidism and pancreatic, pituitary gland, and adrenocortical adenomas. Although the first symptoms of the disease usually occur in patients under the age of 20, the data on MEN1 in children is scarce. Here, we report a case study of a familial MEN1 syndrome with a central nervous system ganglioglioma, a manifestation that has not been characterized so far. CASE REPORT: The diagnosis of a 17-year-old boy with hypoglycemia of unknown origin revealed the presence of a pancreatic tumor. As kidney stone disease and acute pancreatitis were reported in his father, and his asymptomatic sister was initially diagnosed with a pancreatic tumor, a familial MEN1 syndrome was suspected. Indeed, a pathogenic mutation within the MEN1 gene was detected. Further diagnosis revealed primary hyperparathyroidism in both children and their father, which is typical of MEN1. The girl also presented with hydrocephalus caused by ganglioglioma of the central nervous system. Surgical treatment was successfully conducted in both children. CONCLUSIONS: The reported family case provides evidence of the diagnostic and therapeutic difficulties related to the MEN1 syndrome. In children, the benefits of an early surgery should be considered in relation to the risks of possible surgical complications and consequences of a loss of endocrine gland function.

Impact of One-Year Dietary Education on Change in Selected Anthropometric and Biochemical Parameters in Children with Excess Body Weight.

Obesity is regarded as a civilization disease that increases mortality and the risk of cardiovascular complications. In Poland, the prevalence of excess body weight in the paediatric population has been steadily increasing. The consequences of excess body weight in the developmental age population affect children's health and destabilize their development. Appropriate dietary interventions are the main non-invasive methods of preventing and treating obesity. They should be aimed at the whole family, optimally with the use of simple tools such as the Healthy Eating Pyramid. Due to the increasing prevalence of excess body weight in the developmental age population and the problems with the treatment of this condition, studies were undertaken in order to determine the impact of a dietary intervention on anthropometric and biochemical parameters in children with excess body weight. A total of 68 (72.3%) children completed the study. Based on BMI SDS, 59 (86.8%) were diagnosed with obesity and 9 (13.2%) with overweight. After the completion of the one-year dietary educational program, a significant improvement in weight loss, waist and hip circumference, as well as the value of the WHtR index was demonstrated. There was also a significant increase in the percentage of muscle tissue and a decrease in the content of adipose tissue in the bodies of examined children. A significant improvement in the parameters of carbohydrate metabolism, and almost all parameters of lipid metabolism, except for total cholesterol. A significant (by 28.0%) reduction in the incidence of fatty liver was also noted. No influence of dietary education on arterial blood pressure was observed.

Newborn Screening for SCID and Other Severe Primary Immunodeficiency in the Polish-German Transborder Area: Experience From the First 14 Months of Collaboration.

In 2017, in the Polish-German transborder area of West Pomerania, Mecklenburg-Western Pomerania, and Brandenburg, in collaboration with two centers in Warsaw, a partnership in the field of newborn screening (NBS) for severe primary immunodeficiency diseases (PID), mainly severe combined immunodeficiency (SCID), was initiated. SCID, but also some other severe PID, is a group of disorders characterized by the absence of T and/or B and NK cells. Affected infants are susceptible to life-threatening infections, but early detection gives a chance for effective treatment. The prevalence of SCID in the Polish and German populations is unknown but can be comparable to other countries (1:50,000-100,000). SCID NBS tests are based on real-time polymerase chain reaction (qPCR) and the measurement of a number of T cell receptor excision circles (TREC), kappa-deleting recombination excision circles (KREC), and beta-actin (ACTB) as a quality marker of DNA. This method can also be effective in NBS for other severe PID with T- and/or B-cell lymphopenia, including combined immunodeficiency (CID) or agammaglobulinemia. During the 14 months of collaboration, 44,287 newborns were screened according to the ImmunoIVD protocol. Within 65 positive samples, seven were classified to immediate recall and 58 requested a second sample. Examination of the 58 second samples resulted in recalling one newborn. Confirmatory tests included immunophenotyping of lymphocyte subsets with extension to TCR repertoire, lymphoproliferation tests, radiosensitivity tests, maternal engraftment assays, and molecular tests. Final diagnosis included: one case of T-BlowNK+ SCID, one case of atypical Tlow BlowNK+ CID, one case of autosomal recessive agammaglobulinemia, and one case of Nijmegen breakage syndrome. Among four other positive results, three infants presented with T- and/or B-cell lymphopenia due to either the mother's immunosuppression, prematurity, or unknown reasons, which resolved or almost normalized in the first months of life. One newborn was classified as truly false positive. The overall positive predictive value (PPV) for the diagnosis of severe PID was 50.0%. This is the first population screening study that allowed identification of newborns with T and/or B immunodeficiency in Central and Eastern Europe.

Papillary thyroid cancer in three children.

INTRODUCTION: Thyroid cancers (TC) are rare diseases in the pediatric population and represents 0.5-3% of all malignant tumors in children. Differenti-ated thyroid cancer (DTC) is a major TC in children. Every patient under 18 years of age diagnosed with a thyroid nodule should under-go a detailed medical examination. The screening test for children with an increased risk for DTC is ultrasound examination of the neck. Both ultrasound and clinical images of a tissue lesion are more important than its size. It should also be emphasized that autoimmune thyroiditis (AIT), a comorbid condition for TC, is increasingly often diagnosed in young patients. Because of the rare incidence of this kind of cancer, we present 3 case studies of patients with papillary thyroid carcinoma, hospitalized in the Department of Pediatrics, En-docrinology, Diabetology, Metabolic Diseases and Cardiology of Developmental Age at Pomeranian Medical University (PMU) in Szczecin.

Ten years of clinical experience with biosimilar human growth hormone: a review of safety data.

Safety concerns for recombinant human growth hormone (rhGH) treatments include impact on cancer risk, impact on glucose homeostasis, and the formation of antibodies to endogenous/exogenous GH. Omnitrope® (biosimilar rhGH) was approved by the European Medicines Agency in 2006, with approval granted on the basis of comparable quality, safety, and efficacy to the reference medicine (Genotropin®). Additional concerns that may exist in relation to biosimilar rhGH include safety in indications granted on the basis of extrapolation and the impact of changing to biosimilar rhGH from other rhGH treatments. A substantial data set is available to fully understand the safety profile of biosimilar rhGH, which includes data from its clinical development studies and 10 years of post-approval experience. As of June 2016, 106,941,419 patient days (292,790 patient-years) experience has been gathered for biosimilar rhGH. Based on the available data, there have been no unexpected or unique adverse events related to biosimilar rhGH treatment. There is no increased risk of cancer, adverse glucose homeostasis, or immunogenic response with biosimilar rhGH compared with the reference medicine and other rhGH products. The immunogenicity of biosimilar rhGH is also similar to that of the reference and other rhGH products. Physicians should be reassured that rhGH products have a good safety record when used for approved indications and at recommended doses, and that the safety profile of biosimilar rhGH is in keeping with that of other rhGH products.

The Impact of Growth Hormone Therapy on the Apoptosis Assessment in CD34+ Hematopoietic Cells from Children with Growth Hormone Deficiency.

Growth hormone (GH) modulates hematopoietic cell homeostasis and is associated with apoptosis control, but with limited mechanistic insights. Aim of the study was to determine whether GH therapeutic supplementation (GH-TS) could affect apoptosis of CD34+ cells enriched in hematopoietic progenitor cells of GH deficient (GHD) children. CD34+ cells from peripheral blood of 40 GHD children were collected before and in 3rd and 6th month of GH-TS and compared to 60 controls adjusted for bone age, sex, and pubertal development. Next, apoptosis assessment via different molecular techniques was performed. Finally, to comprehensively characterize apoptosis process, global gene expression profile was determined using genome-wide RNA microarray technology. Results showed that GH-TS significantly reduced spontaneous apoptosis in CD34+ cells (p < 0.01) and results obtained using different methods to detect early and late apoptosis in analyzed cells population were consistent. GH-TS was also associated with significant downregulation of several members of TNF-alpha superfamily and other genes associated with apoptosis and stress response. Moreover, the significant overexpression of cyto-protective and cell cycle-associated genes was detected. These findings suggest that recombinant human GH has a direct anti-apoptotic activity in hematopoietic CD34+ cells derived from GHD subjects in course of GH-TS.

Two-Year Data from a Long-Term Phase IV Study of Recombinant Human Growth Hormone in Short Children Born Small for Gestational Age.

INTRODUCTION: This ongoing, prospective, open-label, non-comparative, multicenter phase IV study is evaluating the safety and efficacy of recombinant human growth hormone (rhGH; Omnitrope(®), Sandoz GmbH) in short children born small for gestational age (SGA). Here we report data from patients who have completed 2 years' treatment. METHODS: Eligibility criteria included prepubertal children born SGA with growth disturbances defined as current height standard deviation score (HSDS) <-2.5 and parental adjusted SDS <-1; birth weight and/or length <-2 SDS; and failure of catch-up growth [height velocity (HV) SDS <0 during the last year] by 4 years of age or later. The primary study objective is to assess the long-term effect of Omnitrope treatment on the development of diabetes in short children born SGA. Secondary objectives include evaluation of efficacy, incidence and severity of adverse events (AEs), occurrence of malignancies during treatment, and detection of anti-rhGH antibodies during treatment. RESULTS: In total, 278 children have been enrolled and received study medication; 249 have completed 2 years of treatment. No child has developed diabetes mellitus during the first 2 years; no fasting glucose or 2-h oral glucose tolerance test value exceeded the pre-defined limits of >126 or >200 mg/dL, respectively. No adverse alterations in body mass were noted. Treatment-emergent AEs were experienced by 211 (76.2%) children; most of these were of mild-to-moderate intensity (99.3%) and considered unrelated to study medication (97.6%). Treatment with Omnitrope was effective; mean HSDS was -3.39 at baseline, -2.57 at 1 year and -2.15 at 2 years of treatment. Mean HVSDS (peak-centered) also improved, from -2.13 at baseline to +4.16 at 1 year and +2.23 at 2 years. CONCLUSION: In this second interim analysis, short children born SGA were safely and effectively treated with rhGH (Omnitrope), and 2 years' treatment had no major adverse impact on carbohydrate metabolism or body mass. FUNDING: Sandoz.

Recombinant growth hormone therapy in a girl with Costello syndrome: a 4-year observation.

BACKGROUND: Costello syndrome is a rare syndrome of multiple congenital anomalies. The typical clinical traits include dysmorphic craniofacial features, skin hyperpigmentation and excess, feeding difficulties leading to severe postnatal growth retardation, short stature, joint hypermobility, and delayed psychomotor development. Additionally, Costello syndrome may present with an increased incidence of congenital heart disease, hypertrophic cardiomyopathy, and increased risk of both benign and malignant tumors. Furthermore, cases of patients with endocrine disorders such as adrenal insufficiency and endogenous growth hormone deficiency have also been documented. CASE PRESENTATION: We present a patient with Costello syndrome who has been successfully treated with recombinant human growth hormone (rhGH) for almost 4 years. CONCLUSIONS: The possibility of growth hormone (GH) treatment can be considered in cases of documented GH deficiency in patients with Costello syndrome, but only under close oncologic and cardiologic supervision.

The significance of molecular studies in the long-term follow-up of children with beckwith- wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is a congenital disorder of imprinting caused by epimutations and mutations affecting two imprinted loci on chromosome 11p15. Its clinical features are heterogeneous, including macrosomia, macroglossia, hemihyperplasia, abdominal wall defects, neonatal hypoglycemia, and increased risk of embryonal tumors such as Wilms tumor, adrenocortical carcinoma, hepatoblastoma, and neuroblastoma. The molecular and clinical heterogeneity of BWS makes the diagnosis challenging, but essential, since different etiologies of BWS have different clinical prognoses - most crucially, patients with gain of maternal methylation at imprinting control region type 1 (ICR1) are at significant risk of Wilms tumor or hepatoblastoma. We present three cases of BWS with different symptomatology and two different molecular diagnoses. The authors emphasize the importance of molecular studies in the long-term follow-up of children with BWS, including refinement of phenotype-genotype correlation and its connection with optimal management and tumor surveillance.

Management of familial hypercholesterolemia in children and adolescents. Position paper of the Polish Lipid Expert Forum.

Familial hypercholesterolemia (FH) affects on average 1 in 500 individuals in European countries, and it is estimated that FH in Poland may affect more than 80,000 people. However, in Poland, only about 20% of the population is estimated to have been diagnosed with FH, of which only a small number receive adequate treatment. FH results in more rapid development of atherosclerosis and is associated with a high risk of cardiovascular events. Atherosclerosis develops beginning in childhood in patients with FH and reaches advanced stages before clinical manifestations develop. Inadequate diagnostics and treatment of FH in Polish children suggests a need for raising the level of awareness and understanding of the condition in both society and among health professionals. These recommendations present the current epidemiological status, guidelines for diagnosing FH in Polish children and adolescents, and effective treatment options.

Design of, and first data from, PATRO Children, a multicentre, noninterventional study of the long-term efficacy and safety of Omnitrope(®) in children requiring growth hormone treatment.

OBJECTIVE: To describe the rationale, design and first data from PATRO Children, a postmarketing surveillance of the long-term efficacy and safety of somatropin (Omnitrope(®)) for the treatment of children requiring growth hormone treatment. METHODS: PATRO Children is a multicentre, open, longitudinal, noninterventional study being conducted in children's hospitals and specialised endocrinology clinics. The primary objective is to assess the long-term safety of Omnitrope(®) in routine clinical practice. Eligible patients are infants, children and adolescents (male or female) who are receiving treatment with Omnitrope(®) and who have provided informed consent. Patients who have been treated with another recombinant human growth hormone (rhGH) product before starting Omnitrope(®) are eligible for inclusion. All adverse events (AEs) are monitored and recorded, with particular emphasis on: long-term safety; the recording of malignancies; the occurrence and clinical impact of anti-hGH antibodies; the development of diabetes during Omnitrope(®) treatment in children short for gestational age (SGA); safety issues in patients with Prader-Willi syndrome (PWS). Efficacy assessments include auxological parameters, plus insulin-like growth factor-1 and insulin-like growth factor binding protein-3. RESULTS: As of September 2012, 1837 patients were enrolled in the study from 184 sites in 10 European countries. To date, efficacy data are reassuring and consistent with previous studies. In addition, there have been no confirmed cases of diabetes occurring under Omnitrope(®) treatment, no reports of malignancy and no safety issues in PWS patients. CONCLUSIONS: The efficacy and safety profile of Omnitrope(®) in the PATRO Children study so far are as expected. The ongoing study will extend the safety database for Omnitrope(®), and rhGH products more generally, in paediatric indications. Of particular interest, PATRO Children will add important information on the diabetogenic potential of rhGH in children born SGA, the risk of malignancies in children receiving rhGH, and AEs with a possible causal relationship to rhGH treatment in children with PWS.

Incomplete expression of Klippel-Trenaunay syndrome.

UNLABELLED: Klippel-Trenaunay syndrome (KTS) is a rare, congenital vascular anomaly, defined as a triad including a port-wine stain, underlying bone and soft tissue hypertrophy and varicose veins and/or venous malformations. AIM: Our aim is to present the case of a 13-year-old girl with a delayed proper diagnosis of incomplete expression of KTS presenting with a port-wine stain of her left lower extremity associated with hypertrophy of the affected limb (upon the moment of diagnosis no varicose veins were observed). The patient did not experience any pain in the affected limb, nor was she diagnosed with neuropathy - both of above mentioned symptoms are often a significant issue. To ensure proper diagnosis, the patient underwent a broad spectrum of diagnostic tests, including physical examination with anthropometric measuring, biochemical tests, as well as radiological examinations including CT scan, Doppler vein ultrasound and bone X-ray. Based on physical examination and test results we were able to establish the diagnosis of incomplete expression of Klippel-Trenaunay syndrome. SUMMARY: The authors aim to emphasise the very rare incidence of KTS, as well as the low level of awareness of the described disease, which resulted in the significantly delayed final diagnosis in the presented case. Establishing the diagnosis of KTS before the onset of severe vascular complications, regular check-ups in the Outpatient Clinic of Haemangioma Care and compression dressing may help avoid/diminish the severity and significantly delay the development of venous failure of the affected limb.

Bone marrow of multiorgan donors underutilized: implications for improvement of accessibility of hematopoietic cells for transplantations.

BACKGROUND: The demand for human hematopoietic stem and progenitor cells (HSPCs) for transplantation is increasing. Thus, effective alternative sources of HSPCs are required. Consequently, we sought to expand the accessibility of hematopoietic cells for clinical purposes by the investigation of hematopoietic reconstitution after transplantation of human HSPCs harvested from the bone marrow (BM) of heparinized deceased organ donors (HDODs). METHODS: For multipart research comparison, human BM HDODs-, healthy donor-derived, umbilical cord blood nuclear cells, or CD34(+) cells were transplanted into sublethally irradiated NOD/SCID mice. Twenty-eight days after transplantation nuclear cells were isolated from the murine BM, spleen, and peripheral blood and were used to quantitatively detect human CD45 antigen by quantitative real-time reverse transcriptase-polymerase chain reaction and flow cytometry. The clonogenic growth of human colony-forming units was also investigated. RESULTS: We found that umbilical cord blood-derived HSPCs showed the greatest transplantation potential in our in vivo model. Interestingly, the transplantation potential of HSPCs collected from the BM of HDODs was of the same quality as cells obtained from healthy BM donors. CONCLUSION: Based on these results, we conclude that HDODs are a strongly underappreciated source of HSPCs that are ready to use for clinical purposes.

Parental age as a risk factor for isolated congenital malformations in a Polish population.

Currently available data on the relationship between the prevalence of isolated congenital malformations and parental age are inconsistent and frequently divergent. We utilised the data from the Polish Registry of Congenital Malformations (PRCM) to accurately assess the interplay between maternal and paternal age in the risk of isolated non-syndromic congenital malformations. Out of 902 452 livebirths we studied 8683 children aged 0-2 years registered in the PRCM. Logistic regression was used to simultaneously adjust the risk estimates for maternal and paternal age. Our data indicated that paternal and maternal age were independently associated with several congenital malformations. Based on our data, young maternal and paternal ages were independently associated with gastroschisis. In addition, young maternal age, but not young paternal age, carried a higher risk of neural tube defects. Advanced maternal and paternal ages were both independently associated with congenital heart defects. Moreover, there was a positive association between advanced paternal age and hypospadias, cleft palate, and cleft lip (with or without cleft palate). No significant relationships between parental age and the following congenital malformations were detected: microcephaly, hydrocephaly, oesophageal atresia, atresia or stenosis of small and/or large intestine, ano-rectal atresia or stenosis, renal agenesis or hypoplasia, cystic kidney disease, congenital hydronephrosis, diaphragmatic hernia and omphalocele.

[Hypoparathyroidism with calcifications in the central nervous system in an 8-year-old boy--case report]. / Niedoczynnosc przytarczyc z ogniskami zwapnien w obrebie osrodkowego ukladu nerwowego u 8-letniego chlopca--opis przypadku.

Hypoparathyroidism is a cause of the tetany in children. Except from the signs of generalized neuromuscular irritability it can also present with less characteristic signs of psychomotor development retardation, calcifications in the soft tissues, including CNS. In our report we describe a case of 8-year-old boy in whom hypoparathyroidism revealed for the first time as an episode of seizures and calcifications of the basal ganglia.

Analysis of the sodium iodide symporter expression in histological slides from a nodular goiter.

BACKGROUND: The aim of the study was analysis at both the level and the cell site of the sodium/iodide symporter (NIS) in histological slides from hot, warm, and cold nodules and extranodular parenchyma according to scintigraphy. METHODS: The study population consisted of 97 people who underwent surgery for a toxic nodular goiter (26 patients) or a non-toxic nodular goiter (71 patients). Immunohistochemical study was performed with 198 histological slides from hot, warm, and cold nodules (study slides) and the extranodular parenchyma (control slides). The level of NIS expression was estimated objectively using the computerized image analysis system, Quantimet 600S (Leica, Cambridge, UK). RESULTS: We found significantly higher NIS expression in hot nodules than in cold nodules and in warm nodules than in cold ones. We found significantly higher NIS expression in hot and warm nodules than in the surrounding parenchyma. The level of NIS expression did not differ significantly between cold nodules and the collateral tissues. CONCLUSIONS: Our data indicate that NIS protein participates in the development of hyperthyroidism in the course of a nodular goiter. We confirm that the functional state of a nodular goiter is determined by NIS expression in nodules, not in collateral parenchyma. The low metabolism of cold nodules does not simply result from decreased level of NIS protein or its defective targeting to the cell membrane. The observation of NIS in the cell cytoplasm of hot nodules seems to indicate that the intracellular localization of NIS does not determine loss of its activity.