Thyroid-stimulating antibody (TSAb) detected in sera of Graves'' patients using human thyroid cell cultures

As a homologous system is required to evaluate the effect of thyroid-stimulating antibody (TSAb) present in the serum of Graves' patients, primary cultures obtained from normal human thyroid gland have been used and the stimulatory effect measured as an increase of cAMP intracellular levels.

Monolayer cell cultures were stimulated by IgG purified from sera of Graves' patients or control subjects and compared to the effect of bovine TSH. Bovine TSH produced a dose-dependent increase in cAMP intracellular levels between 0·05 mU and 2·5 mU/ml, reaching a maximal value after 30 min with higher doses. While normal IgG had no effect, IgG prepared from untreated patients with frank Graves' disease elicited a significant increase in cAMP accumulation at a concentration between 0·05 and 0·5 mg/ml within 60 min in thirteen out of fourteen patients. A longer incubation period showed no further increase in cAMP values, even if in one case a higher concentration (5·0 mg/ml) of Graves' IgG had a delayed response. When the cAMP intracellular level modifications produced by Graves' IgG preparations in thyroid cell cultures were compared to those evoked in thyroid slices, an identical percentage (93%) of positive cases was obtained, without a coincidence of negative cases. Using thyroid slices the cAMP intracellular increase above basal levels was higher, if considered as a percentage, but in cultured cells a very low IgG concentration was sufficient to detect the presence of TSAb. No correlation between the two assays was found.

In conclusion, normal human cultured thyroid cells appeared to be a more suitable substrate when compared to human thyroid slices for detecting the presence of TSAb in Graves' disease and for studying its effect on thyroid cells. However, a 100% TSAb positivity was present in our Graves' patient series only when both assays were used.

     

Psychopathological traits and 5-HT2A receptor promoter polymorphism (-1438 G/A) in patients suffering from Anorexia Nervosa and Bulimia Nervosa

Various studies have evaluated the possible role of the -1438G/A polymorphism within the 5-HT2A receptor gene in the susceptibility to Eating Disorders (EDs). One hundred and forty-eight ED patients (EDp) and 89 control subjects were interviewed by means of the Eating Disorder Examination (EDE) and analyzed for distribution of the -1438G/A polymorphism. Patients with the AA genotype suffering from Anorexia Nervosa and Bulimia Nervosa showed higher Weight and Shape Concern (P = 0.003 and P = 0.010, respectively) scores and greater overall severity of the ED psychopathology (EDE total score) (P = 0.012). The obtained preliminary data suggest the use of dimensional psychopathological measures in ED genetic studies.     

Intrathyroidal lymphocytes from non toxic multinodular goiter: no evidence for production of thyroid stimulating antibodies

Although an autoimmune pathogenesis for non toxic goiter has been suggested, reports concerning circulating antibodies to TSH receptor structures have been conflicting. Intra thyroid lymphocytes, capable of secreting IgG, have been shown to be involved in the pathogenesis of Graves' and Hashimoto's diseases; therefore, the ability of conditioned media obtained from intra thyroid lymphocyte culture, and of IgG purified from these media, to stimulate cAMP accumulation and [3H]-Thymidine (TdR) uptake in FRTL-5 cells was investigated. The activity of IgG produced "in vitro" was compared with that of circulating IgG. Thyroid tissue samples were obtained at surgery from 21 patients with non toxic multinodular goiter (MNG), 5 patients with active Graves' disease (GD), and from 10 normal subjects, undergoing neck surgery for non-thyroidal pathology. IgG purified from media of GD lymphocyte cultures stimulated both cAMP accumulation and [3H]-TdR in 5 out of 5 cases: all of the IgG purified from control or MNG lymphocyte culture media was not active in either assay. Circulating IgG did not affect cAMP accumulation or [3H]-TdR in any of the non toxic MNG cases: controls showed no changed at all. However, both activities represented were increased by GD IgG. Conditioned media from intra thyroid lymphocyte cultures significantly inhibited basal cAMP accumulation in 7 out of the 21 non toxic MNG samples and totally abolished the response in all GD patients. [3H]-TdR was not affected by IgG of any of the controls, but it had an inhibitory effect on 8 out of 21 non toxic MNG patients, and significantly stimulated [3H]-TdR in all GD patients. In conclusion, present data demonstrate that intra thyroid lymphocytes from non toxic MNG do not produce antibodies capable of mimicking TSH actions through the adenylate cyclase cascade. Conversely, soluble factors interacting in TSH-mediated functions of FRTL-5 cells are present in conditioned media of intra thyroid lymphocytes of GD and MNG thyroid lymphocytes of GD and MNG thyroid cultures.     

Conversion of treatment from cefoxitin to ampicillin/sulbactam: experience in a university teaching hospital

A 12-month trial, conducted in a 650-bed university teaching hospital, evaluated the conversion from cefoxitin to ampicillin/sulbactam. This report discusses the methodology used to evaluate the feasibility of the change and the challenges encountered during the trial period. The effect of cost and overall therapeutic outcome were other aspects of the evaluation. Results indicate that a conversion from cefoxitin to ampicillin/sulbactam is not only feasible but is also a realistic approach to achieving high-quality, cost-effective care.     

National Cholesterol Education Program and International Diabetes Federation definitions of metabolic syndrome in the prediction of diabetes. Results from the FIrenze-Bagno A Ripoli study

Background:  The International Diabetes Federation (IDF) proposed to modify the diagnostic criteria for metabolic syndrome (MS) previously issued by the National Cholesterol Education Program (NCEP). Aim of the present investigation is to compare the predictive value for diabetes of NCEP and IDF definitions of MS in a large sample of predominantly Caucasian subjects.
Methods:  A prospective observational study was performed on a cohort study (n = 3096) enrolled in a diabetes-screening programme, the FIrenze-Bagno A Ripoli study. All subjects with fasting glucose >126 mg/dl and/or post-load glucose ≥200 mg/dl (5.7%) were excluded from the present analysis. Follow-up of each subject was continued until diagnosis of diabetes, death or until 31 December 2005. Mean follow-up was 27.7 ± 11.3 months.
Results:  Among subjects enrolled, 13.7 and 25.2% were affected by MS using NCEP and IDF criteria respectively. During follow-up, 38 new cases of diabetes were diagnosed, with a yearly incidence rate of 0.5%. The relative risk for diabetes in subjects with MS was 10.10 [5.13; 20.00] and 7.87 [3.70; 16.7] using NCEP and IDF definitions respectively. After adjustment for age, sex, fasting glucose and waist circumference, NCEP-defined MS, but not IDF-, was significantly associated with incident diabetes (hazard ratio, 95% CI: 2.41 [1.01; 5.95] and 2.05 [0.80; 5.29] respectively).
Conclusions:  Although the reasons for the proposed changes in diagnostic criteria for MS are easily understandable, the newer IDF definition, while increasing estimates of prevalence of the syndrome, reduces the effectiveness of MS in identifying subjects at risk for diabetes. Further research is needed before the previous NCEP criteria are abandoned.     

Sex steroids and odorants modulate gonadotropin-releasing hormone secretion in primary cultures of human olfactory cells

Olfactory neurons and GnRH neurons share a common origin during development. In the nasal epithelia, GnRH neurons persist throughout fetal life and adulthood. The fate and function of these neurons in vivo have remained unknown. In a previous in vitro study, we isolated, cloned, and propagated primary long term cell cultures from the olfactory neuroepithelium of 8- to 12-week-old human fetuses. These cells expressed both neural proteins as well as olfactory genes and were responsive to odorant stimuli. We now report that these human olfactory cells also express the GnRH gene and protein. Combined HPLC and RIA studies have indicated that these cells release authentic GnRH in spent media. The release of GnRH was time dependent and was positively affected by sex steroids and odorants. Immunohistochemical data demonstrated the presence of sex steroid receptors in these cells. The presence of the alpha- and beta-subtypes of the estrogen receptor was also demonstrated by RT-PCR and Western blot analysis. When the cells were stimulated with increasing concentrations of 17beta-estradiol in the presence of a fixed concentration of progesterone (10(-7) mol/L), the combination of the two steroids induced a 3- to 4-fold increase in GnRH secretion. This stimulatory effect was completely blunted by tamoxifen. Neither 17beta-estradiol nor progesterone was effective when tested separately. Treatment with increasing concentrations of the odorant, l-carvone, induced a time- and dose-dependent dramatic increase in GnRH protein release (1000-fold increase) and gene expression. Repeated application of the stimulus resulted in a progressive lower responsiveness of the cells. To our knowledge, this is the first time that primary cell cultures from human fetal olfactory neuroepithelium have been shown to express and release GnRH. Our results also demonstrate that these cultures, which are sensitive to sex steroids and odorants, can be useful models in the study of the complex array of regulatory factors that finely tune GnRH secretion in humans.