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Biomedical subjects

M D'Armiento

Publications and source records attributed to M D'Armiento.

At least 19 recordsLinked to original sources
PubMed1992

Thyroid hormone stimulates glucose transport and GLUT1 mRNA in rat Sertoli cells.

The transport of 2-deoxyglucose (dGlc) by cultured rat Sertoli cells was stimulated by L-triiodothyronine (T3) in a time and dose-dependent manner. The lag-time was of about 6 h, the half-maximal dose (ED50) was 0.47 nM, which correlates with the Kd of the nuclear T3 receptor of rat Sertoli cells (Kd = 1-2 nM), and the stimulation was maintained up to 24 h. The effect was specific, as judged by the order of potency of T3 analogs. Cycloheximide prevented the stimulatory effect without affecting the basal uptake. T3 stimulated the uptake of the glucose analog 3-O-methylglucose (MeGlc) with the same order of potency as that of dGlc. The ontogenetic profile of the T3 effect coincides with that of T3 nuclear receptors in rat Sertoli cells. Northern blot analysis demonstrated that Sertoli cells express the erythrocyte/brain glucose transporter isoform (GLUT1) but not the adipose/muscle isoform (GLUT4). T3 treatment (10(-7) M for 24 h) induces an increase of GLUT1 mRNA level comparable to that of glucose analog uptake. These results suggest that thyroid hormone stimulates glucose transport by increasing the synthesis of new glucose transporter units and give further evidence for a direct effect of thyroid hormone in the modulation of Sertoli cell functions.

3-O-Methylglucose↗
PubMed1991

Renal tubular dysgenesis and very large cranial fontanels in a family with acrocephalosyndactyly S.C. type.

We describe the first case of renal tubular dysgenesis in a newborn female who survived 15 days. The immunohistochemical and lectin binding studies confirmed the lack of proximal tubule differentiation. Electron microscopy showed undifferentiated tubular epithelium. Widely patent cranial fontanels were present in the proposita. The father and sister showed acrocephalosyndactyly Saethre-Chotzen type. The parents were not related and there was no familial history of renal pathology.

Abnormalities, Multiple↗
PubMed1991

The effects of iodoprophylaxis on thyroid size during pregnancy.

Thyroid gland size was ultrasonographically determined in 35 pregnant women who live in an area with moderate iodine deficiency. Iodide salt was administered to group A (n = 17), whereas group B (n = 18) was used as a control. Each group was tested for thyroid-stimulating hormone serum levels, iodine excretion, and thyroid volume. In both groups thyroid-stimulating hormone levels were similar and did not change throughout pregnancy. The iodine excretion at the third trimester in the treated group was significantly (p less than 0.01) higher than that of group B (100.0 +/- 39.0 versus 50.0 +/- 37.0 micrograms iodine per 24 hours, respectively). Initially, thyroid volume did not differ between the two groups. At the end of pregnancy, no difference was found in thyroid size in group A, whereas in the untreated women it increased significantly (p less than 0.0001) with a mean increase of 1.6 +/- 0.6 ml (16.2% +/- 6.0%). These results show that the increased thyroid size in the control group was mainly a result of relative iodine deficiency and that iodoprophylaxis should be warranted even in areas with moderate iodine deficiency to prevent the increase in thyroid size and, probably, to avoid the risk of maternal and fetal hypothyroidism.

Adult↗
PubMed1991

Monitoring of serum alpha-fetoprotein levels in children with chronic hepatitis B virus infection.

Changes in serum alpha-fetoprotein (alpha FP) levels were investigated by radioimmunoassay during the follow-up (17 +/- 12 months, two to three times per year) of 50 children with chronic hepatitis B virus infection (mean age of 8 years, 30 males) and of 35 healthy age- and sex-matched controls. Eleven of 50 were healthy carriers; 7 had chronic persistent hepatitis, 29 had chronic active hepatitis, and 3 had cirrhosis-associated chronic active hepatitis. Serum alpha FP levels in controls were found to be always lower than 5 ng/ml (0.1-4.4 ng/ml, mean +/- SD of 1.34 +/- 1.32 ng/ml). Statistical analysis after logarithmic transformation showed a significant difference between mean levels (ng/ml) in controls and in patients [geometric mean = 0.83 C.L. (95% confidence limits of 1.19/0.58) vs. 3.43 (95% C.L. of 4.79/2.45); p = 0.0001]. Mean values of serum alpha FP levels at entry were higher than those found at the end of the follow-up period [geometric mean = 3 (95% C.L. of 4.69/1.92) vs. 1.48 (95% C.L. of 2.13/0.95); p = 0.038]. Only three patients repeatedly showed high alpha FP levels (76.7, 122.8, and 1,600 ng/ml at entry): alpha FP values became normal after a mean follow-up of 17 +/- 7.8 months as well as liver enzymes, with no changes in serum "e" antigen-antibody and anti-delta antibody status being observed. Mean values of serum alpha FP levels in HBeAg-positive patients were significantly higher than in HBeAg-negative patients both at entry and during the follow-up (p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Effect of thyroid hormone on the pre- and post-natal development of the rat testis.

The relationship between thyroid function and testicular development in the rat was investigated. Hypothyroidism was induced during fetal or post-natal life by adding methimazole (MMI) to the drinking water of pregnant or lactating mothers. A group of newborn rats was treated with MMI and i.p. injections of L-tri-iodothyronine (L-T3). Hypothyroidism was shown by the reduced serum levels of total T3 and of total thyroxine (T4) in pregnant mothers and in pubertal rats. Testes were studied using light microscopy at 18 and 21 days post coitum or during puberty (21, 35 and 50 days after birth); serum levels of gonadotrophins were also evaluated in pubertal rats. Hypothyroidism had no effect on testicular development during fetal life and when induced in newborn rats it was associated at puberty with reduced serum levels of FSH and LH and with delayed maturation of the testis compared with control rats. The delay in maturation consisted of a reduction in the diameter of seminiferous tubules, and a reduction in the number of germ cells per tubule; this was associated with increased degeneration and arrested maturation of germ cells. In addition, Sertoli cells demonstrated retarded development, as indicated by a delay in the appearance of cytoplasmic lipids and in the development of a tubule lumen. Hormonal and morphological abnormalities were absent in rats treated with MMI plus L-T3. In conclusion, hypothyroidism occurring soon after birth caused reduced levels of gonadotrophins in the serum and a delay in pubertal spermatogenesis, possibly due to retarded differentiation of the Sertoli cells.

Animals↗
PubMed1990

Ontogenesis of the nuclear 3,5,3'-triiodothyronine receptor in the rat testis.

The aim of this study was to investigate the ontogenesis of the nuclear T3 receptor among the different cell types in the rat testis from fetuses at the 19th day of gestation and animals 1, 5, 15, 20, and 60 days after birth. Whole testis, tubular fraction, nontubular fractions, and Sertoli cells cultured in vitro or enriched in vivo by irradiation were used. The results demonstrate that high affinity, low capacity T3-binding sites are localized only in Sertoli cells; the binding specificity and affinity (Kd ranges from 0.8 +/- 0.2 to 2.6 +/- 0.4 nM) do not change significantly with the age of the animals and are comparable to those observed for T3 receptors in other mammalian tissues. In the whole testis, the concentration of receptors changes during gonadal development, being maximally expressed in the fetus (154.3 +/- 8.1 fg T3 bound/10(6) nuclei) and from 1 (203.4 +/- 10.9 fg T3 bound/10(6) nuclei) to 5 (185.3 +/- 15.1 fg T3 bound/10(6) nuclei) days of postnatal life, decreasing significantly at 15 and 20 days (65.4 +/- 2.0 and 57.9 +/- 1.9 fg T3 bound/10(6) nuclei, respectively) and being virtually absent in the adult. The same change in receptor concentration was found in Sertoli cells obtained by different techniques. This ontogenetic profile coincides with the pattern of Sertoli cell proliferation and differentiation, thus suggesting a role of thyroid hormones in the regulation of growth and maturation of the somatic cells of the seminiferous epithelium.

Animals↗
PubMed1989

Cutaneous lichen amyloidosis associated with multiple endocrine neoplasia type 2A.

We have previously described a kindred with hereditary medullary thyroid carcinoma and pheochromocytoma (multiple endocrine neoplasia type 2A [MEN 2A]) with localized pruritic cutaneous manifestations present only in affected members. Although the initial skin biopsies reported did not show amyloidosis, subsequent skin biopsy results reported here have demonstrated amyloid which stained for keratin but not for calcitonin and established that this family represents an association of a rare autosomal dominant form of lichen amyloidosis with MEN 2A.

Adrenal Gland Neoplasms↗
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↗
PubMed1986

[Current diagnostic technics in the prediction of the functional recovery of a urographically silent kidney].

25 patients with a silent kidney, because of obstructive uropathy, have been studied. Authors' aim was to find out some parameters which could be able to predict renal function recovery once the obstruction was removed. 99m Tc DTPA renal scintiscanning, renal ultrasonography, and the study of renal clearances on the urine obtained via a percutaneous nephrostomy were executed. The authors observed that when the nuclide renal uptake is absent a minimal functional recovery is still possible and it may be foretold only analysing the urine collected through a percutaneous nephrostomy.

Adult↗
PubMed1984

Lack of inhibition of anterior pituitary hormone release during chronic treatment with calcium antagonists.

Calcium antagonists are widely used for the treatment of cardiovascular disorders, especially ischaemic heart disease. It has been demonstrated that these drugs, either in vitro or acutely administered in humans, inhibit the basal and stimulated secretion of pituitary hormones by blocking calcium influx through slow calcium channels. To see if a similar effect could be detected after their chronic administration, we studied the basal, TRH- and LHRH-stimulated TSH, PRL, LH and FSH release in 18 male subjects with chronic stable angina before and on the 30th day of oral treatment with verapamil (n = 8;80 mg three times a day) or with nifedipine (n = 10; 10 mg three times a day). Neither drug had any effect on basal TSH, PRL, LH and FSH values or on their response to the specific hypothalamic-releasing hormones. These results suggest that the chronic administration of calcium antagonists, at the usual therapeutic doses, does not effect the process of stimulus-secretion coupling of anterior pituitary hormones, ruling out any impairment of the related target glands which have been expected on the basis of previous studies.

Aged↗
PubMed1984

Transitory subclinical and permanent hypothyroidism in the course of subacute thyroiditis (de Quervain).

Sixty-two patients affected with subacute thyroiditis (SAT) were followed for a mean period of 14 months (range 1-40), by monitoring thyroid hormone levels in basal condition, pituitary TSH reserve, antithyroglobulin (TgAb) and antimicrosomal antibodies ( MsAb ), in order to study the natural course of the disease and to characterize its intermediate phase. In the first phase the mean serum iodothyronine levels were within normal limits, nevertheless elevated T3 and T4 levels were detected in 34 (54%) and 20 (32%) patients, respectively. The next phase was characterized by normal serum iodothyronine levels; TRH stimulation test, however, showed a significant increase of pituitary TSH reserve in 35 (56%) patients. All parameters reverted gradually towards normal in all but 3 patients, who showed overt permanent hypothyroidism. TgAb and MsAb were positive in the early stage in 15 (24%) and 40 (64%) patients, respectively, disappearing at the end of the follow-up period in all but one patient; this particular patient belonged to the group of 3 patients affected with permanent hypothyroidism. Our data indicate that the onset of SAT is characterized by transient hyperthyroidism and that transient subclinical hypothyroidism characterizes the next phase. TRH stimulation test is required for the diagnosis of the latter and for the identification of the few who develop permanent hypothyroidism.

Adolescent↗
PubMed1983

17 alpha-hydroxylase deficiency: mineralocorticoid hormone profiles in an affected family.

The plasma concentrations of mineralocorticoid hormones, basal and after stimulation and suppression with ACTH, can identify the heterozygotes in a family with two siblings with 17 alpha-hydroxylase deficiency. Both parents and one sibling had elevated levels of plasma deoxycorticosterone, corticosterone, 18-hydroxydeoxycorticosterone, and 18-hydroxycorticosterone, but normal cortisol and aldosterone concentrations. Stimulation with ACTH effected additional increases in the elevated steroid and cortisol levels, but not in aldosterone, further increasing the discrepancy and the ratio between 18-hydroxycorticosterone and aldosterone. One sibling had normal steroid patterns and an 18-hydroxycorticosterone to aldosterone ratio. Suppression of ACTH restored the steroids to low normal levels. In addition, the ratio of the gas chromatographic analysis of the total major urinary metabolites of corticosterone to total metabolites of cortisol was greater, and the sum of urinary androsterone and etiocholanolone to total corticosterone and cortisol metabolites was less in the heterozygotes than in normal subjects. This identifies deficient 17-hydroxylation, which is required for the production of cortisol and C-19 steroids. These criteria appear unique for the 17 alpha-hydroxylase defect in the heterozygote.

18-Hydroxycorticosterone↗
PubMed1982

[Inhibition of the biosynthesis of thyroglobulin with propranolol in the rat].

Thyroglobulin biosynthesis was studied in thyroid glands of rats treated during 30 days with a daily dose of propranolol, a non-selective beta-adrenergic blocking drug. Studies were carried out by extraction of soluble proteins from homogenates after incubation of the glands in presence of [3H]-4,5-L-leucine and [3H]-D-1-galactose. Thyroglobulin 19S, 12S and 4-8S soluble proteins were separated and identified by ultracentrifugation in a saccharose gradient. The glands of rats treated with propranolol showed a decreased amount of soluble proteins as well as a decreased incorporation of [3H] labeled markers. 19S thyroglobulin is poorly represented, but very large amounts of the 12S monomer are present; this suggests an impairment in the dimerization of the 12S subunit, absent in normal controls. This impairment could be due to a structure modification. Propranolol reduces the biosynthesis of thyroglobulin in thyroid gland as well as the formation of T3 from T4 in peripheral tissues; its therapeutical use against thyrotoxicosis is thus justified. The study of its action on the dimerisation of the 12S subunit could be of interest to clear the mechanism of thyroglobulin biosynthesis.

Animals↗