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Biomedical subjects

A Pinchera

Publications and source records attributed to A Pinchera.

At least 127 records · Page 7Linked to original sources

Radiation dose to the testes after 131I therapy for ablation of postsurgical thyroid remnants in patients with differentiated thyroid cancer.

UNLABELLED: Radioiodine-131 is used in differentiated thyroid cancer (DTC) for ablation of postsurgical thyroid remnants and destruction of metastases. The question may be raised of whether 131I treatment of DTC in male patients may give an irradiation dose to the testes that could impair fertility. Few data in the literature concern the dose absorbed by the testes after 1311 therapy for DTC. Because 131I kinetics may be altered by the hypothyroid condition commonly present at the time of treatment and by the radioiodinated iodoproteins released by the damaged thyroid tissue, the dose values reported in the International Commission on Radiological Protection (ICRP) tables for euthyroid men may not be appropriate. To clarify this problem, three male subjects undergoing 131I therapy for ablation of thyroid remnants shortly after thyroidectomy for DTC were studied. METHODS: The mean administered activity was 1256 MBq, and the duration of the study was 2 wk. The gamma dose was measured by thermoluminescent dosimeters (TLDs) applied to the lower poles of the testes. Correction factors were calculated for the distance of the TLD from the center of the testes and for attenuation by the testes of the gamma rays reaching the TLD. After correction, the gamma dose to the testes ranged from 21 to 29 mGy. The gamma dose calculated by the Medical Internal Radiation Dose (MIRD) method from blood and urine samples was similar (18-20 mGy) to that measured by TLDs. The beta dose was estimated by the MIRD method from blood activity and testicular volume and ranged between 14 and 31 mGy. RESULTS: The total (beta and gamma) doses to testes were 30, 33 and 43 microGy/MBq in the three subjects. CONCLUSION: These values are close to those derived from the ICRP tables (26-37 microGy/MBq 131I) for euthyroid subjects. The present data indicate that significant irradiation is delivered to the testes after the administration of the 131I ablative dose to thyroidectomized patients. The relevance of the radiation absorbed by testes on fertility remains to be established.

Administration, Oral↗

Graves' ophthalmopathy and 131I therapy.

Graves' ophthalmopathy is an autoimmune process initiated and maintained by antigen(s) shared by the thyroid and the orbit. A matter of argument concerns the choice of the method of treatment for Graves' hyperthyroidism when clinically evident ophthalmopathy is present. Restoration of euthyroidism appears to be beneficial for ophthalmopathy. On the other hand the continuing disease activity associated with the recurrence of hyperthyroidism appears to adversely affect the course of ophthalmopathy. For these reasons it is our opinion that in patients with Graves' hyperthyroidism and ophthalmopathy the permanent control of thyroid hyperfunction by ablation of thyroid tissue should be obtained by radioiodine therapy or thyroidectomy. The rationale for an ablative strategy is the following: i) permanent control of hyperthyroidism avoids exacerbations of eye disease associated with recurrence of hyperthyroidism; ii) hypothyroidism, which follows thyroid tissue ablation, should be regarded as a therapeutic end point rather than as an undesirable result; iii) ablation of thyroid tissue may result in the removal of both the thyroid-orbit cross-reacting antigen(s) and the major source of thyroid-autoreactive lymphocytes. The relationship between radioiodine therapy and the course of GO is a matter of controversy, and some authors have suggested that radioiodine administration may be associated with a worsening of preexisting ophthalmopathy. This was not observed when radioiodine treatment was associated with a 3-month oral course of prednisone. The development or progression of GO after radioiodine therapy might be due to the release of thyroid antigens following radiation injury and to subsequent exacerbations of autoimmune reactions directed towards antigens shared by the thyroid and the orbit. The view that radioiodine therapy may be associated with a progression of ophthalmopathy is not shared by some authors who claim that the apparent link between progression of ophthalmopathy and radioiodine therapy might simply be coincidental, reflecting the natural history of the disease. The radioiodine-associated exacerbation of eye disease might be used as an argument against the use of radioiodine therapy in patients with ophthalmopathy. We do not share this view, since the outward effects of radioiodine on eye disease can easily be prevented by concomitant administration of glucocorticoids. Glucocorticoid treatment should be limited, in our opinion, to patients with clinically evident eye disease and to those without ophthalmopathy but with other known risk factors, such as smoking.

Graves Disease↗

[Orbital decompression in Grave's disease: comparison of techniques].

Grave's ophthalmopathy is an inflammatory, autoimmune disorder often associated with Grave's disease. The inflammatory infiltration involves the retrobulbar fatty tissue and the extrinsic eye muscles, causing proptosis, extraocular muscle dysfunction and often diplopia. Orbital decompression is an effective treatment in such cases, particularly when resistant to drugs and external radiation therapy. This work compares the results of orbital decompression performed by removing: a) the medial and lateral walls (Mourits technique) in 10 patients (19 orbits) and b) the medial and lower walls (Walsh-Ogura technique) in 17 patients (31 orbits). The results show that removing the floor of the orbit enables better reduction of proptosis but more easily leads to post-operative diplopia. Thus it proves necessary to combine the two techniques, modifying the surgical approach on a case-by-case basis.

Decompression, Surgical↗

Cigarette smoking and treatment outcomes in Graves ophthalmopathy.

BACKGROUND: It is unclear whether smoking affects the course of Graves ophthalmopathy and therapeutic outcomes. OBJECTIVE: To observe smoking behavior in a randomized study of the effect of radioiodine therapy on ophthalmopathy and in a case series of patients with Graves ophthalmopathy receiving orbital radiation therapy and glucocorticoids. DESIGN: Randomized, single-blind study of smoking and mild ophthalmopathy after radioiodine therapy (study 1) and a retrospective cohort study of the association between smoking and response of severe ophthalmopathy to treatment (study 2). SETTING: University medical center. PATIENTS: 300 patients with mild ophthalmopathy (study 1) and 150 patients with severe ophthalmopathy (study 2). INTERVENTION: In study 1, patients received radioiodine alone or radioiodine and a 3-month course of oral prednisone (initial dosage, 0.4 to 0.5 mg/kg of body weight per day). In study 2, patients received high-dose oral prednisone for 6 months (initial dosage, 80 to 100 mg/d) and underwent orbital radiation therapy by linear accelerator (cumulative dose, 20 Gy per eye over 2 weeks). MEASUREMENTS: Degree of ophthalmopathy was assessed by overall evaluation (inflammatory changes, proptosis, extraocular muscle dysfunction, corneal involvement, and optic neuropathy). RESULTS: In study 1, ophthalmopathy progressed in 4 of 68 nonsmokers (5.9% [95% CI, 3% to 9%]) and 19 of 82 smokers (23.2% [CI, 13% to 33%]) who received radioiodine alone (P = 0.007). Ophthalmopathy was alleviated in 37 of 58 nonsmokers (63.8% [CI, 51% to 78%]) and 13 of 87 smokers (14.9% [CI, 10% to 26%]) who received radioiodine plus prednisone (P < 0.001). In study 2, 61 of 65 nonsmokers (93.8% [CI, 90% to 98%]) and 58 of 85 smokers (68.2% [CI, 57% to 78%]) responded to treatment (P < 0.001). CONCLUSIONS: Cigarette smoking increases the risk for progression of ophthalmopathy after radioiodine therapy and decreases the efficacy of orbital radiation therapy and glucocorticoid therapy.

Adult↗

Prevalence of thyroid autoantibodies in children and adolescents from Belarus exposed to the Chernobyl radioactive fallout.

BACKGROUND: The long-term effects of ionising radiation, including radioiodine, on thyroid function are not well known. We compared thyroid immunity and function in two groups of children from Belarus, one of whom was exposed to the radioactive fallout of Chernobyl. METHODS: We measured serum free thyroxine 4 (free T4), free T3, and thyrotropin hormone (TSH) and the prevalence of thyroid autoantibodies (antithyroglobulin and antithyroperoxidase), in 287 children or adolescents living in Hoiniki (average caesium contamination of 5.4 Ci/km2). We also studied 208 children and adolescents living in Braslav (average contamination <0.1 Ci/km2), who were age 12 years or less at the time of the Chernobyl accident. FINDINGS: The prevalence of antithyroglobulin or antithyroperoxidase, or both, was significantly higher (p=0.0001) in individuals living in Hoiniki (56 [19.5%] of 287) than in those living in Braslav (eight [3.8%] of 208). In both villages, no sex differences were found in the antibody prevalence before age 13 years. Thereafter, a significantly higher prevalence of thyroid autoantibodies was found in girls from Hoiniki. The increase in the prevalence of circulating antibodies in the contaminated group was already apparent in individuals who, at the time of the accident, were in utero or newborn (15.7%), and was even more pronounced in children of 9 years or more (35.1%). No major alterations of serum FT-4, FT-3, or TSH were found. INTERPRETATION: 6-8 years after the Chernobyl accident, a significant increase in thyroid autoimmunity was found in children exposed to radioactive fallout. Pubertal age in girls is a risk factor for increased prevalence of thyroid autoimmunity. The autoimmune phenomena are limited to an increased prevalence of circulating thyroid autoantibodies without evidence of significant thyroid dysfunction. The future development of clinically relevant thyroid autoimmune diseases, especially hypothyroidism, is a possibility.

Adolescent↗

Simian virus 40-like DNA sequences in human papillary thyroid carcinomas.

Sequences of the SV40 virus, a virus of Asian macaques, have been found in human tumors, such as pleural mesotheliomas, ependimomas and choroid plexus tumors. Transgenic mice carrying the SV40 large T gene under the transcriptional control of the thyroglobulin gene promoter, develop thyroid dedifferentiation and follicular thyroid cell proliferation, leading to thyroid hyperplasia and adenocarcinomas. On these bases we investigated the presence of SV40 DNA sequences in 69 samples of papillary thyroid carcinomas (PTC) and in other thyroid and non-thyroid carcinomas, as well as in benign thyroid diseases. By Southern blot and PCR amplification followed by sequence analysis, we found the presence of SV40-related sequences integrated in the tumoral DNA of three cases of PTC. At least the 203 bp fragment of the aminoterminus of large T antigen, the 294 bp fragment of the VP1 gene and the 483 bp entire regulatory region were present in the tumoral DNA of these patients. SV40 sequences were not found in tissues other than PTC. Our results demonstrate that, in addition to previous findings in mesotheliomas and brain tumors, SV40 is somehow linked to papillary thyroid carcinoma. Although our data do not demonstrate a causative role in the development of PTC, this possibility must be considered and requires further studies.

Adolescent↗

Relation between therapy for hyperthyroidism and the course of Graves' ophthalmopathy.

BACKGROUND: The chief clinical characteristics of Graves' disease are hyperthyroidism and ophthalmopathy. The relation between the two and the effect of treatment for hyperthyroidism on ophthalmopathy are unclear. METHODS: We studied 443 patients with Graves' hyperthyroidism and slight or no ophthalmopathy who were randomly assigned to receive radioiodine, radioiodine followed by a 3-month course of prednisone, or methimazole for 18 months. The patients were evaluated for changes in the function and appearance of the thyroid and progression of ophthalmopathy at intervals of 1 to 2 months for 12 months. Hypothyroidism and persistent nyperthyroiaism were promptly corrected. RESULTS: Among the 150 patients treated with radioiodine, ophthalmopathy developed or worsened in 23 (15 percent) two to six months after treatment. The change was transient in 15 patients, but it persisted in 8 (5 percent), who subsequently required treatment for their eye disease. None of the 55 other patients in this group who had ophthalmopathy at base line had improvement in their eye disease. Among the 145 patients treated with radioiodine and prednisone, 50 (67 percent) of the 75 with ophthalmopathy at base line had improvement, and no patient had progression. The effects of radioiodine on thyroid function were similar in these two groups. Among the 148 patients treated with methimazole, 3 (2 percent) who had ophthalmopathy at base line improved, 4 (3 percent) had worsening of eye disease, and the remaining 141 had no change. CONCLUSIONS: Radioiodine therapy for Graves' hyperthyroidism is followed by the appearance or worsening of ophthalmopathy more often than is therapy with methimazole. Worsening of ophthalmopathy after radioiodine therapy is often transient and can be prevented by the administration of prednisone.

Adolescent↗

Stromal IGF-II messenger RNA in breast cancer: relationship with progesterone receptor expressed by malignant epithelial cells.

In breast cancer, insulin-like growth factor II (IGF-II) is stromal in origin and is considered an important regulator of tumour epithelium growth. The presence of progesterone receptor (PR) is expression of an intact oestrogen regulatory pathway of breast malignant epithelial cells and represents a parameter of cell differentiation in breast cancer. In this study we have examined the relationship between IGF-II mRNA expression and ER, PR content in 75 breast cancer. Formalin-fixed paraffin-embedded tissue sections were used to preserve histological details. IGF-II mRNA was evaluated by in situ hybridisation method and ER, PR by immunohistochemistry. IGF-II mRNA was scored semi-quantitatively: 2.6% breast tumour specimen expressed no IGF-II mRNA, 46.7% had low levels of expression (IGF-II-) and 50.7% had moderate or high IGF-II mRNA content (IGF-II+). IGF-II mRNA was found in the stroma fibroblasts surrounding malignant lesions and no signal was detected in malignant epithelial cells. In contrast, ER and PR were expressed only by neoplastic epithelial cells and no immunoreactivity was found in the stroma: 50/75 (66.6%) breast cancer specimens were positive for ER (ER+) and 35 (46.6%) for PR (PR+). Both, IGF-II mRNA and PR were directly correlated with the stromal proliferation (p < 0.05 and p < 0.001, respectively). No relationship was found between IGF-II RNA and ER. In contrast 24/35 (73.5%) PR breast cancer tissues were IGF-II+ (p < 0.01) and a strong correlation was found between epithelial PR immunostaining and stromal IGF-II mRNA content (p < 0.003). Our data indicate that in breast cancer IGF-II mRNA is generally expressed by stromal cells and ER and PR by epithelial cancer cells, and that IGF-II mRNA expression is strongly related with both percentage and staining intensity of PR+ epithelial cancer cells. These data support the hypothesis that IGF-II produced by the fibroblasts may exert a paracrin effect on malignant epithelium regulating its differentiation.

Breast Neoplasms↗

Detection of a new de novo mutation at codon 251 of exon 8 of thyroid hormone receptor beta gene in an Italian kindred with resistance to thyroid hormone.

Resistance to thyroid hormone (RTH) is almost invariably associated with mutations of the thyroid hormone (TH) receptor beta (hTR beta) gene and is inherited as an autosomal dominant disease. Mutations of hTR beta identified in patients affected by RTH cluster generally at two spots of the ligand binding domain. We investigated whether an Italian kindred with RTH had a mutation in the thyroid hormone (TH) receptor beta gene. Blood samples were obtained from the available family members for biochemical and genetic analyses. Thyroid function tests in basal conditions, and in the case of the propositus also following incremental doses of T3, were performed. Exon 4 to 10 of hTR beta gene were amplified using the polymerase chain reaction (PCR) and the mutation was identified by direct sequence analysis. The affinity constant of this mutated receptor for T3 was measured by in vitro transcription-translation and was then compared with that of wild type. We identified a heterozygous G to A transition at nucleotide 1037 of exon 8 at codon 251, resulting in a glycine (G) to glutamic acid (E) substitution (G251E) in the patient affected by RTH and in his affected offspring, but not in the normal family members. This novel mutation represents a de novo mutation since both parents of the index case were unaffected and did not have this genomic mutation. When expressed in vitro, the mutant protein (G251E) showed a marked decrease of the affinity for T3, suggesting an impaired ligand-dependent transactivation activity of this mutant receptor. In vivo studies with incremental doses of L-T3 demonstrated a reduced sensitivity to TH in the index case, in particular at the pituitary level where the thyrotrophs' activity was not completely inhibited even by 200 micrograms/day of L-T3. G251E mutation represents the fourth mutation described up to now in exon 8 of hTR beta among the subjects affected by RTH. A third cluster of mutations of the c-erbA beta gene located proximally with respect to the other two so far described begins to emerge in RTH patients.

Adult↗

Chronic recurrent stress due to panic disorder does not precipitate Graves' disease.

A role of psychic stress in precipitating hyperthyroid Graves' disease has been suggested, but the evidence in support of this pathogenetic mechanism is conflicting. In this study we investigated the possible occurrence of Graves' disease in patients with panic disorder, a psychiatric condition characterized by recurrent endogenous stress. The study group included 87 consecutive patients suffering from panic disorder since 1 to 30 years: 17 males (mean age 31.3, range 26-43 years) and 70 females (mean age 37.6, range 15-73 years). Two hundred and sixty-two normal subjects with no present or past history of psychiatric disorder served as controls. Patients were submitted to a full evaluation of the thyroid that included physical examination, assays for free thyroid hormones, TSH, thyroglobulin (TgAb), thyroperoxidase (TPOAb) and TSH receptor (TRAb) antibodies, and thyroid echography. The prevalence of circulating TgAb and/or TPOAb in patients with panic disorder did not differ from that in the control group. Twelve patients with panic disorder (13.7%) had circulating TgAb and/or TPOAb, but none had TRAb. Three out of 12 patients with thyroid antibodies, indicating a genetic susceptibility to autoimmune thyroid disease, had a family history of clinical thyroid autoimmunity, and 4 of them had a hypoechogenic pattern of the thyroid at ultrasound suggesting autoimmune thyroiditis. None of the patients with panic disorder had a previous history of hyperthyroidism. On examination, clinical hyperthyroidism or endocrine ophthalmopathy were not found in any of them. A small goiter was appreciated by palpation in 16 patients (18.3%). Free thyroid hormones and TSH were within the normal range in all patients but one: a 55-year old lady with normal serum free thyroid hormones and undetectable TSH. During an 18-month follow-up she did not develop hyperthyroidism and her TSH spontaneously returned in the normal range. Considering the individual duration of panic disorder, evidence for previous or present Graves' hyperthyroidism was not found for a total of 478 patient-years of exposure to recurrent endogenous stress in the whole study group, and for a total of 39 patient-years in patients with a genetic susceptibility to autoimmune thyroid disease. In conclusion, we found that recurrent endogenous stress did not precipitate Graves' hyperthyroidism in a series of 87 patients with panic disorder, encompassing a total of 478 patient-years of exposure to stress. Failure to activate the hypothalamic-pituitary-adrenal axis by endogenous stress due to panic disorder as opposed to exogenous stress due to life-events might explain why panic disorder does not precipitate Graves' hyperthyroidism.

Adolescent↗

Thyroid autoimmunity and aging.

Aging is associated with the appearance of several serum autoantibodies, including thyroid autoantibodies. The biological and clinical significance of this phenomenon is still unknown, because, with the exception of primary myxedema, the prevalence of clinically overt thyroid autoimmune diseases is not increased in the elderly. The peculiar link between autoimmune thyroid failure and aging is also underscored by the high prevalence of subclinical hypothyroidism in elderly subjects with positive serum thyroid autoantibodies, and could be the consequence of preferential age-dependent expression of destructive effector mechanisms and/or increased target gland susceptibility. Thyroid autoimmunity and subclinical hypothyroidism have been also implicated in the pathogenesis of other age-associated disorders, in particular coronary heart disease. Interestingly, recent data from our laboratories showed that thyroid autoantibodies are rare in healthy centenarians and in other highly selected aged populations, while they are frequently observed in unselected or hospitalized elderly. Taken together, these data suggest that thyroid autoimmune phenomena are not the consequence of the aging process itself, but rather might be related to age-associated disease.

Aging↗

PAX8 mutations associated with congenital hypothyroidism caused by thyroid dysgenesis.

Permanent congenital hypothyroidism (CH) is a common disease that occurs in 1 of 3,000-4,000 newborns. Except in rare cases due to hypothalamic or pituitary defects, CH is characterized by elevated levels of thyroid-stimulating hormone (TSH) resulting from reduced thyroid function. When thyroid hormone therapy is not initiated within the first two months of life, CH can cause severe neurological, mental and motor damage. In 80-85% of cases, CH is associated with and presumably is a consequence of thyroid dysgenesis (TD). In these cases, the thyroid gland can be absent (agenesis, 35-40%), ectopically located (30-45%) and/or severely reduced in size (hypoplasia, 5%). Familial cases of TD are rare, even though ectopic or absent thyroid has been occasionally observed in siblings. The pathogenesis of TD is still largely unknown. Although a genetic component has been suggested, mutations in the gene encoding the receptor for the thyroid-stimulating hormone (TSHR) have been identified in only two cases of TD with hypoplasia. We report mutations in the coding region of PAX8 in two sporadic patients and one familial case of TD. All three point mutations are located in the paired domain of PAX8 and result in severe reduction of the DNA-binding activity of this transcription factor. These genetic alterations implicate PAX8 in the pathogenesis of TD and in normal thyroid development.

Amino Acid Sequence↗

Endoscopic parathyroidectomy: report of an initial experience.

BACKGROUND: Preoperative localization of parathyroid lesions and intraoperative quick parathyroid hormone (PTH) assay have been proposed to minimize the extent of operation in primary hyperparathyroidism. To this purpose, endoscopic procedures have been introduced recently. METHODS: During a period of 13 months, 39 of 65 consecutive patients with primary hyperparathyroidism were selected for endoscopic parathyroidectomy on the basis of the following criteria: preoperative echographic diagnosis of a single adenoma, absence of nodular goiter, and no prior neck operations. Unilateral neck exploration and excision of the adenoma was performed through a gasless procedure combined with intraoperative PTH measurements. Mean follow-up after the operation was 7 months (range 1 to 13 months). RESULTS: Thirty-nine parathyroid adenomas were removed; the mean diameter was 21 mm (range 5 to 30 mm). The mean operative time was 65 minutes (range 30 to 180 minutes). In all cases PTH concentration decreased significantly. Patients who underwent endoscopic parathyroidectomy had less postoperative pain compared with patients who underwent conventional hemithyroidectomy. At follow-up, serum calcium and PTH levels were normal in all cases. CONCLUSIONS: Endoscopic parathyroidectomy proved to be a feasible surgical procedure that can be performed in an acceptable operative time with an excellent cosmetic result. The gasless approach avoided any emphysema.

Adult↗

Endoscopic parathyroidectomy by a gasless approach.

Endoscopic approach for the treatment of primary hyperparathyroidism is one of the new fields of interest for minimally invasive surgery. The removal of the parathyroid gland can be achieved either by a gas or gasless technique. Massive carbon dioxide (CO2) diffusion and absorption has been reported to occur during the gas procedure. Endoscopic techniques that do not rely on CO2 insufflation have still to be set. We have developed a new procedure that was offered to 20 selected patients with a localized parathyroid adenoma. A 3-minute CO2 insufflation (12 mm Hg) through a conventional trocar inserted under the strap muscles is used just to anatomically dissect the virtual thyrotracheal groove. Actually, the working space is maintained by means of skin retractors so as to allow needlescopic instruments to perform a parathyroid adenomectomy with the gasless procedure. In all cases the parathyroid adenoma was removed through a 1.5-cm skin incision. Quick parathyroid hormone assays always confirmed the removal of all pathologic glands and permitted unilateral cervical exploration. Mean operative time was 71.7 +/- 35.5 minutes. No complication was registered. At follow-up, all patients were normocalcemic. This new endoscopic approach to the neck seems to be safe, effective, and cosmetically satisfactory.

Adenoma↗

Activating thyrotropin receptor mutations in histologically heterogeneous hyperfunctioning nodules of multinodular goiter.

Activating thyrotropin (TSH) receptor mutations have been found in toxic adenomas and in hot nodules contained in toxic multinodular goiter. The typical feature of multinodular goiter is the heterogeneity in morphology and function of different follicles within the same enlarged gland. In this report we describe a patient with a huge multinodular goiter, normal free triiodothyronine (FT3) and free thyroxine (FT4) serum values, and subnormal TSH serum concentration. Thyroid scintiscan showed two hot areas corresponding to the basal and apical nodules of the left lobe. The right lobe was poorly visualized by the radioisotope. The patient underwent thyroidectomy, and histological examination of the tissue was performed. Genomic DNA was extracted from the tissue specimen and direct sequencing of the TSH receptor and Gs alpha genes was done. At histology, one hyperfunctioning nodule had the typical microscopic structure of thyroid adenomas, and the other contained multiple macrofollicular areas not confined by a capsule. In spite of this histological difference, both hyperfunctioning nodules harbored a mutation of the thyrotropin receptor (TSHr) gene: an isoleucine instead of a threonine in position 632 (T632I) in the first nodule and a methionine instead of an isoleucine in position 486 (I486M) in the second nodule. In conclusion, our findings show for the first time that gain-of-function TSHr mutations are not only present in hyperfunctioning thyroid nodules with the histological features of the true thyroid adenomas, but also in hyperfunctioning hyperplastic nodules contained in the same multinodular goiter.

Cyclic AMP↗