Miguel Angel Navarro

Interactions between serum leptin, the insulin-like growth factor-I system, and sex, age, anthropometric and body composition variables in a healthy population randomly selected.

objective Leptin secretion is influenced by many factors and the GH/IGF axis plays an important role in the regulation of body composition, but the physiological interactions between leptin and the IGF‐I system remain unknown. In this study we investigated the relationship between leptin, the IGF‐I system, and sex, age, anthropometric and body composition variables in a group of healthy adults randomly selected.

Altered 5-HT2A binding sites and second messenger inositol trisphosphate (IP3) levels in hippocampus but not in frontal cortex from depressed suicide victims

The binding parameters of 5-HT(2A) and levels of its second messenger, 1,4,5-trisphosphate (IP(3)), were simultaneously studied in frontal cortex and hippocampus from the brains of 18 control subjects and 18 depressed suicide victims. All suicides met DSM-III-R criteria for depressive symptoms, suffered a violent death and had not taken any antidepressant drugs for at least 6 months prior to death. A significant decrease in the number of 5-HT(2A) binding sites (154+/-22 vs. 254+/-36 fmol/mg), together with a significantly lower apparent affinity constant (1.02+/- 0.08 vs. 1. 36+/-0.09 nM), was detected in hippocampus but not in frontal cortex from the depressed suicides compared to the control subjects. Furthermore, IP(3) concentrations were significantly increased in hippocampus (3.2+/-0.3 vs. 2.1+/-0.3 pmol/g) but not in frontal cortex (1.3+/-0.3 vs. 2.7+/-0.5 pmol/g) from the suicide victims. The reported results may indicate a significant hypersensitivity of the 5-HT(2A) postsynaptic receptor located in the hippocampus from depressed suicide victims, giving rise to an enhancement of its intracellular signaling system with higher IP(3) production.

Altered 5-HT2A and 5-HT4 Postsynaptic Receptors and Their Intracellular Signalling Systems IP3 and cAMP in Brains from Depressed Violent Suicide Victims

Serotonin 5-HT2A and 5-HT4 binding parameters and their second messengers 1,4,5-inositol triphosphate (IP3) and cyclic adenosyl monophosphate (cAMP) were studied in the frontal cortex, hippocampus, caudate nucleus and amygdala of 19 control subjects and 19 antidepressant-free, violent suicide victims. A significantly higher number of 5-HT4 receptors and higher second messenger cAMP concentrations were found in the frontal cortex and caudate nucleus of the depressed suicide victims as compared with the control group. Furthermore, significantly increased 5-HT2A binding sites and IP3 concentrations were noted in the caudate nucleus of the suicide victims, together with a significantly reduced number of 5-HT2A binding sites, higher binding affinity and increased IP3 concentrations in the hippocampus. No significant alterations in 5-HT4 and cAMP or in 5-HT2A and IP3 concentrations were observed in the amygdala. The caudate nucleus of depressed suicide victims seems to be the brain region with the highest alteration of the serotonergic system, and hence with the most diagnostic sensitivity. Further studies on suicidality and depression should focus on the functionality of the caudate nucleus.

Usefulness of an ACTH Test in the Diagnosis of Nonclassical 21-Hydroxylase Deficiency among Children Presenting with Premature Pubarche

Adrenal steroidogenic function was evaluated in 55 children with typical premature pubarche (PP) to investigate the incidence of late-onset congenital adrenal hyperplasia (LOCAH) due to 21-hydroxylase (21-OH) deficiency and to evaluate the usefulness of routine ACTH testing in these patients. Four patients fulfilled criteria for LOCAH due to 21-OH deficiency. Of these, 3 had elevated baseline 17-OHP levels; in the remainder, basal 17-OHP was within normal limits. Mean basal and stimulated 17-OHP responses in children with PP, excluding those with an enzymatic defect, were very similar to those of controls (2.3 +/- 1.8 vs. 1.6 +/- 0.9 and 10.0 +/- 4.0 vs. 9.5 +/- 3.3 nmol/l, respectively). However, 5 patients had basal 17-OHP values exceeding the upper limit of controls and 8 patients, including 2 of those with elevated baseline levels, showed supranormal poststimulated 17-OHP values. Body mass indices, height standard deviation scores (SDS) and bone age SDS showed no correlation with the basal or incremental rises of any hormone. Four (7%) of our population of patients with typical PP had LOCAH due to 21-OH deficiency. Basal 17-OHP levels were helpful in detecting altered steroidogenesis in 3, thus suggesting that in some PP patients, LOCAH due to this enzymatic defect may remain undiagnosed if ACTH stimulation test is not routinely performed.

Epidermal growth factor in plasma and saliva of patients with active breast cancer and breast cancer patients in follow-up compared with healthy women.

We measure EGF in saliva and plasma from 52 patients with active breast cancer, 22 breast cancer patients in follow-up (non-active) and 33 healthy women. EGF concentrations in saliva were significantly higher in patients with active and non-active breast cancer than healthy women, whereas the opposite results were found in plasma. The highest values of EGF in saliva were found in the local recurrence subgroup.

Variations in [3H]imipramine and 5-HT2A but not [3H]paroxetine binding sites in suicide brains

Both the [3H]imipramine and [3H]paroxetine binding sites and the 5-HT2A receptor were simultaneously determined in frontal cortex, cingulate cortex, hippocampus and amygdala from 17 control subjects and 17 depressed suicide victims. A significant decrease in the maximum binding (Bmax) of [3H]imipramine was observed in the hippocampus of suicide victims as compared to control subjects (160 +/- 25 vs. 328 +/- 52 fmol/mg protein; P = 0.007) without changes in the apparent affinity constant (Kd). Furthermore, a significant decrease in the number of 5-HT2A binding sites, together with a significantly lower Kd, was also observed in the hippocampus of suicides as compared to control subjects (129 +/- 18 vs. 225 +/- 32 fmol/mg protein; P = 0.02 and 0.91 +/- 0.07 vs. 1.38 +/- 0.08 nM, respectively; P = 0.006). [3H]Paroxetine binding did not display modifications between the two groups in either Bmax or Kd from any of the brain regions studied. When all four brain regions were taken together, a down-regulation was noted between presynaptic [3H]imipramine binding and the postsynaptic 5-HT2A receptor (r = -0.40; P = 0.0013) in the control group. This correlation did not appear in the suicide group. No correlation was observed between [3H]paroxetine binding and the 5-HT2A receptor in either control subjects or suicides. Taken together, these results suggest that the 5-HT uptake site measured with [3H]imipramine and the 5-HT2A receptors are reliable markers of serotonergic dysfunction.

Constitutive and Regulated Secretion of Epidermal Growth Factor and Transforming Growth Factor-β1 in MDA-MB-231 Breast Cancer Cell Line in 11-Day Cultures

Epidermal growth factor (EGF) and transforming growth factor type beta1 (TGF-beta1) exert opposite effects in most cells. A potential regulation between the two factors has been studied at a transcriptional level, but never at a protein level. MDA-MB-231 is a breast carcinoma cell line which possesses large quantities of membrane receptors and expresses high activities for both factors. In this study, conditioned mediums (CM) of 11-day cultures of these cells were collected to measure EGF and TGF-beta1 by immunochemical assays. Four types of cultures were tested: (1) controls; (2) after treatment with 17-beta-estradiol; (3) treated with EGF; and (4) treated with TGF-beta1. These cells secreted constitutively quantifiable concentrations of both factors to the CM. EGF treatment inhibited TGF-beta1 levels in CM throughout the study period (P = 0.002), while EGF levels diminished after TGF-beta1 treatment (P = 0.05). This finding suggests a dual regulation between EGF and TGF-beta1, at a protein level, in this cell line.

Profile, mean residence time of ACTH and cortisol responses after low and standard ACTH tests in healthy volunteers

Objective  No consensus exists until now about the suitable dose of tetracosactin in the ACTH stimulation test for detecting adrenal insufficiency. Our aim was to characterize both the ACTH(1–24) and the cortisol profiles after standard high‐dose test (250 µg) (HDT) and low‐dose test (1 µg) (LDT) in healthy subjects in order to provide a deeper knowledge about the relationship between stimulus and response.

Secretion and dual regulation between epidermal growth factor and transforming growth factor-β1 in MDA-MB-231 cell line in 42-hour-long cultures

MDA-MB-231 is a breast cancer cell line which possesses large quantities of epidermal growth factor (EGF) receptors and specific high-affinity transforming growth factor-beta1 (TGF-beta1) receptors. We have established that these cells secrete constitutively measurable levels of EGF and TGF-beta1 in conditioned medium. The constitutive secretion of EGF decreased over time in culture (42 h), while the constitutive secretion of TGF-beta1 remained constant. TGF-beta1 secretion in EGF-treated cells was lower than in controls (P < 0.0001), but EGF concentrations were not modified after TGF-beta1 supplement. We postulate that in MDA-MB-231 cell line there is a dual regulation between both growth factors.

Growth of MDA-MB-231 cell line: different effects of TGF-beta(1), EGF and estradiol depending on the length of exposure.

The human cell line MDA‐MB‐231 is a prototype for the study of hormone‐independent breast cancer. Modification of cell growth behaviour has been observed after treating these cells with growth factors. EGF is a typical stimulatory growth factor for many cell types, whereas transforming growth factor β1(TGF‐β1) acts with inhibitory character. Here we observed cell growth inhibition after EGF as well as after TGF‐β1treatments. Nevertheless, in the 42‐h experiments, EGF‐treated cultures grew before (18 hours) respect to the TGF‐β1and E2‐treated cultures (24h), and in the 11‐day experiments, EGF‐treated cultures started growing (7 days) after TGF‐β1‐treated cultures (5 days). Estradiol inhibited the proliferation of these cells only after several days of treatment.