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S Lio

Publications and source records attributed to S Lio.

14 recordsLinked to original sources
PubMed1992

Charge and pH effect on the early events of Epstein-Barr virus fusion with lymphoblastoid cells (Raji).

Fusion of Epstein-Barr virus (EBV) with Raji cells was measured after exposure of the virus to neutral or low pH, enzymatic modification of the viral spike glycoproteins, or chemical modification of the target membrane. The relief of octadecylrhodamine (R18) fluorescence self-quenching was used to monitor fusion. Fusion of EBV with Raji cells at pH 5.9 was significantly enhanced compared to that at neutral pH. Treatment of Raji cells with agents known to modify the surface net charge (trinitrobenzene sulfonic acid) totally prevented fusion at a neutral pH. Desialylation of EBV significantly reduced the extent of fusion with Raji cells. Our results demonstrate that EBV is rapidly internalized and then fuses with lymphoblastoid cells in the endocytic vesicles.

Cells, Cultured↗
PubMed1990

Is zinc deficiency a cause of subclinical hypothyroidism in Down syndrome?

In Down syndrome there is a high incidence of overt or subclinical hypothyroidism as well as some immunological defects, early thymic involution associated to low serum zinc levels. Zinc supplementation to the diet has been reported to transiently improve thymic function; moreover thymic function has been shown to be in relation with the pituitary-thyroid axis. The aim of this study was to evaluate if, in Down patients, zinc therapy could improve also thyroid function, by determining serum levels of total and free thyroid hormones and basal TSH levels. In 52 patients studied, we found a high incidence of subclinical hypothyroidism (30%); in 17 patients treated with zinc sulphate we showed a reduction of FT3. More significantly, we detected 9 patients with low zinc levels in which zinc supplementation improved thyroid function, thus reducing the incidence of subclinical hypothyroidism.

Adolescent↗
PubMed1989

Role of smoking in goiter morphology and thyrotropin response to TRH in untreated goitrous women.

Three groups of women were evaluated for TSH response to TRH and for goiter morphology by means of thyroid ultrasonography: group A = goitrous nonsmokers; group B1 = goitrous moderate-smokers; group B2 = goitrous heavy-smokers. They were compared with a control group (group C) made up nongoitrous, nonsmoking women. The size of the goiter was not correlated with the daily consumption of cigarettes, even though in heavy smokers a nodular goiter was prevalent as shown by ultrasonography. The serum values of TT3 showed significant differences between nonsmokers and heavy smokers (p less than (p less than 0.005), whereas the serum values of TT4 and of basal TSH showed no statistically significant differences. On the contrary, the TSH response to TRH showed a significant difference between heavy and nonsmokers (p less than 0.05). In conclusion, it has been demonstrated that goitrous cigarette heavy smokers show: i) A prevalence of statistically significant nodular goiter; ii) A significantly higher TT3 serum levels; iii) A significantly higher re-of TSH to TRH. These data suggest that cigarette smoking favors the development of nodular goiter and can involve the central regulation of the hypothalamus-pituitary-thyroid interaction.

Adult↗
PubMed1989

[Is there a double pathway for the secretion of thyroglobulin: a "short circuit" weakly glycosyl-iodinated and a "long circuit" strongly glycosyl-iodinated?].

Intact rat thyroid lobes incubated in vitro release recently synthesized thyroglobulin (Tg) into the media at a faster rate than they release thyroglobulin stored in follicular structures. Differential release of this Tg fraction cannot be explained by morphological alterations in thyroid architecture during incubation. This rapidly excreted fraction exhibits a low density on rubidium chloride gradients characteristic of poorly sialylated and poorly iodinated thyroglobulin, comigrating on rubidium chloride gradients with thyroglobulin isolated from tunicamycin treated glands. This poorly sialylated and poorly iodinated thyroglobulin is itself unaffected in its density or release into the media by tunicamycin treatment. Tg isolated from the media of tunicamycin treated glands has nearly the same low iodine and low sialic acid content as rat serum thyroglobulin and does not incorporate radiolabelled glucosamine. This fraction thus appear to duplicate properties of low glycosylated-low iodinated thyroglobulin released from thyroid cells in organisms that have no follicular structures and no follicular storage process as well as from thyroid tissue in patients with thyroid disease states, particularly thyroid tumors. Thus it is proposed a "short loop" pathway of low-glycosylated low-iodinated thyroglobulin directly into circulation, that bypasses and is not stored in the follicular lumen, the "long loop".

Animals↗
PubMed1988

Enzymatic deglycosylation of human thyroglobulin: fluorescence studies.

The interaction between the carbohydrate and the amino acid residues in human thyroglobulin has been studied. Previous reports showed that the removal of the two terminal carbohydrates of the complex chains leads to an increase in thyroglobulin binding to thyroid membranes. In our study, after enzymatic release with glycosidases of the sugar moieties from thyroglobulin, a time-dependent decrease in tryptophan fluorescence has been observed. This decrease was also associated with a shift in the emission peak from 335 to 340 nm. The strong quenching of tryptophan emission was also accompanied by a decrease in the exposure of tryptophan residues, as shown by a Stern-Volmer analysis with the neutral quencher acrylamide. These data, together with the increase in fluorescence of the dansylated deglycosylated thyroglobulin, strongly suggest that a significant conformational change of thyroglobulin follows the deglycosylation of the protein.

Apoproteins↗
PubMed1988

[Endogenous opiate modulators of insulin secretion in the obese].

The effects of endogenous opiates on insulin response to oral glucose load were studied in obese subjects and in lean healthy volunteers. None of these having a family diabetes. After 3 days on an 1,800 cal./m2, 40% carbohydrate diet all subjects underwent two standard 75 g oral glucose tolerance tests (OGTT), one of which was accompanied by an i. v. administration of 10 mg of, an antagonist of opiates, the naloxone. In one group of obese impaired oral glucose tolerance test occurred. All obese, but not the lean healthy volunteers, showed: 1) increased basal plasma insulin levels, 2) higher insulin response to OGTT, 3) a decrease in insulin response to OGTT after naloxone administration, with significant differences at 60 min (p less than 0.01) and 90 min (p less than 0.025). In none of the subjects significant differences were observed in blood glucose levels after OGTT plus naloxone administration. These data suggest that increased endogenous opiates may affect insulin response to glucose in obese with impaired or normal oral glucose tolerance test. At present there seems to be no satisfactory explanation for unchanged blood glucose levels during OGTT with and without naloxone despite a decrease in insulin secretion in the obese patients.

Adolescent↗
PubMed1988

Thyroid and pituitary function following allogeneic bone marrow transplantation.

Thyroid function was evaluated in 13 consecutive patients with chronic myelogenous leukemia to verify in allogeneic bone marrow transplantation if the fractionated irradiation protocol with low dose rate, previously applied to reduce the damage to various organs, also prevents the 43% incidence of primary hypothyroidism that occurs after the administration of single dose with higher dose rate. Following bone marrow transplantation, decreased plasma levels of total thyroxine and triiodothyronine and impaired response of thyrotropic cells to thyrotropin-releasing hormone were observed. These alterations reverted to normal in nine months and none of the patients was hypothyroid at the end of follow-up. The damage to thyrotropic cells appears to be selective because the secretion of prolactin was not impaired and that of gonadotropins even increased, as a consequence of gonadal failure. Longer follow-up is needed to determine if this irradiation protocol, which prevents the complication of permanent primary hypothyroidism and does not cause any destruction of thyroid cells, may increase the risk of irradiation-related thyroid tumors.

Adolescent↗
PubMed1987

[Changes in the ratio of T-lymphocyte subpopulations in various cytological samples of Plummer's thyroid adenoma].

UNLABELLED: In order to correlate possible alterations of cell-mediated immune response with the evolutive phases of Plummer Adenoma (P. A.), T lymphocytes subpopulations in FNA samples and in peripheral blood lymphocytes (PBL) have been studied in 5 patients with autonomous nodules. The lymphocyte component in FNA and peripheral blood has been isolated by Lymphoprep gradient centrifugation; the analysis of T helper and T suppressor subpopulations was made by indirect immunofluorescence with OKT8 and OKT4 monoclonal antibodies. Our results show a reduction in OKT4/OKT8 ratio in cytological samples compared with PBL in patients with P. A., while in control subjects there was not statistically significant difference. In the patients with P. A., the relative increase of OKT8 lymphocytes in FNA compared with PBL is correlated with the functional state, that is toxic adenomas have a lower OKT4/OKT8 ratio compared with nodules in pre-toxic phase. IN CONCLUSION: T lymphocyte subpopulations typing in FNA demonstrate that, even in this type of hyperthyroidism, immune response disorders are present and consist of relative increase of suppressor/cytotoxic T cells, compared to T helper cells.

Adenoma↗
PubMed1986

[Polymorphism of human thyroxine binding serum globulin (TBG); existence of a new form of serum protein without detectable triiodothyronine binding power].

Two kinds of TBG polymorphism are described in human, one found in deglycosylated TBG from individual blood donors, the other is a genetically determined polymorphism. TBG from plasma samples from a patient with toxic goiter, not autoimmune, (p)TBG, from the patient's mother (m)TBG and from individual donors (n)TBG, were labeled with [125I]T4 or [125I]T3 and submitted to isoelectric focusing (IEF), followed by autoradiography. Three faint [125I]T4 radiolabeled bands were detectable in (p)TBG while four strong [125I]T4 radiolabeled bands were detectable in (m)TBG and (n)TBG), respectively. IEF of the [125I]T3 incubated serum samples resulted in no detectable isoelectric radiolabeled band for (p)TBG while a normal pattern was found in (m)TBG and in (n)TBG, respectively. These data suggest a new intraindividual not linked to sexual chromosome X polymorphism characterized by a loss in hormone binding.

Adult↗
PubMedDate not supplied

[Autonomous thyroid nodule: relations between clinical symptomatology and goiter endemia].

Sixty-three patients with autonomous thyroid nodule were studied, thirty-five from an endemic goiter area (EA) and twenty-eight from a non-endemic goiter area (NEA). Clinical history, physical examination, ultrasonography, thyroid hormone levels, and fine needle aspiration (FNA), were utilized to investigate whether or not iodine deficiency determined differences in the latency of progression to toxicity, the seriousness of illness and thyroid hormone levels. No significant difference was observed in the age of onset of nodularity, while the latency of progression to toxicity was significantly decreased in the EA (p less than 0.001). The ultrasonographic pattern did not show significant volume variations between the EA and NEA, but there was a slight prevalence of multinodular lesions in EA. No significant difference in serum thyroid hormone levels was found between the two areas in non toxic patients, while at the onset of hyperthyroidism higher levels of FT were observed in the EA than in the NEA. FNA showed a prevalence of colloid lesions in EA, while hyperplastic lesions prevail in the NEA. Forty-two patients underwent surgery: the extent of surgery was greater in patients from the EA. In conclusion, in iodine deficient areas earlier clinical thyrotoxicosis and a higher prevalence of hypoactive thyroid nodules were observed. Furthermore, in EA, the autonomous nodule in non toxic phase is more frequently associated with colloid lesions than hyperplastic lesions.

Adult↗