Search PubMed⌕ Search

Biomedical subjects

S Bernasconi

Publications and source records attributed to S Bernasconi.

At least 19 recordsLinked to original sources
PubMed2003

Mitochondrial dysfunction and death in motor neurons exposed to the glutathione-depleting agent ethacrynic acid.

This study investigated the mechanisms of toxicity of glutathione (GSH) depletion in one cell type, the motor neuron. Ethacrynic acid (EA) (100 microM) was added to immortalized mouse motor neurons (NSC-34) to deplete both cytosolic and mitochondrial glutathione rapidly. This caused a drop in GSH to 25% of the initial level in 1 h and complete loss in 4 h. This effect was accompanied by enhanced generation of reactive oxygen species (ROS) with a peak after 2 h of exposure, and by signs of mitochondrial dysfunction such as a decrease in 3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyltetrazolium bromide (MTT) (30% less after 4 h). The increase in ROS and the MTT reduction were both EA concentration-dependent. Expression of heme oxygenase-1 (HO-1), a marker of oxidative stress, also increased. The mitochondrial damage was monitored by measuring the mitochondrial membrane potential (MMP) from the uptake of rhodamine 123 into mitochondria. MMP dropped (20%) after only 1 h exposure to EA, and slowly continued to decline until 3 h, with a steep drop at 5 h (50% decrease), i.e. after the complete GSH loss. Quantification of DNA fragmentation by the TUNEL technique showed that the proportion of cells with fragmented nuclei rose from 10% after 5 h EA exposure to about 65% at 18 h. These results indicate that EA-induced GSH depletion rapidly impairs the mitochondrial function of motor neurons, and this precedes cell death. This experimental model of oxidative toxicity could be useful to study mechanisms of diseases like spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS), where motor neurons are the vulnerable population and oxidative stress has a pathogenic role.

Animals↗
PubMed2003

Transition from pediatric to adult care of children with chronic endocrine diseases: a survey on the current modalities in Italy.

We report on a survey carried out in 65 pediatric and adult endocrinological centers concerning: 1) the modalities of the transfer of children with chronic endocrine diseases from pediatricians to adult endocrinologists, 2) opinions and suggestions from physicians of the Centers, and 3) specific details regarding GH deficiency. The main results are: 1) The mean age of transfer is around 18 yr of age. 2) The reasons for the transfer are personal convincement of pediatricians in 47%, administrative reasons in 37% and patient's desire in 16% of cases 3) In the majority of cases a discharge summary is sent by the pediatrician to the endocrinologist often followed by a phone call, whereas 30% of endocrinologists do not send a report back to pediatricians. 4) Less than half of the Centers are satisfied with the modalities of the transfer and the remainder complain about the lack of communication, no common guidelines, and differences in the management of patients. However, all are willing to try to improve this important time for adolescents with chronic diseases. 5) As far as GH deficiency is concerned, the main differences between pediatric and adult endocrinological centers are the different tests used to re-evaluate the diagnosis and the higher doses of GH used by pediatricians to treat young adults. In conclusion, considering the interest and desire of physicians, a structural intervention of the scientific societies to help to overcome problems is highly desirable.

Adolescent↗
PubMed2003

Growth and pubertal disorders in neurofibromatosis type 1.

The first textbook of Pediatric Endocrinology in the early 1950s reported an association of neurofibromatosis type 1 (NF1) and precocious puberty (PP) and/or short stature. Recent studies have indicated that children with NF1 grow normally until puberty; thereafter height velocity and relative height (SDS or percentiles) decreases with respect to healthy peers, reaching a mean adult height close to the 25th percentile for the general population. Moreover, the percentage of patients with true short stature (<3rd percentile) increases from childhood (5%) to late puberty (20-30% in literature, 18% in our study), and final height is significantly below the genetic target and predicted adult height calculated just before or at the beginning of puberty. Finally, among the shortest patients (<10th percentile) there is a high incidence of severe complications, such as CNS tumors, huge plexiform neurofibromas and severe scoliosis. Precocious puberty is a frequent complication of NF1, and occurs mainly in association with optic pathway tumors (OPT); however, occasionally it has been reported in the absence of optic gliomas, probably with a similar incidence as in the general population. GnRH agonist therapy must be decided individually as in some patients further growth could be normal and/or treatment would not improve final height. In the presence of early pubertal signs, an OPT must be ruled out. In addition to PP, delayed puberty has been frequently reported in NF1. In a study of 123 girls with NF1, we found that the mean age at menarche (13.0 +/- 1.9 yr) was later than in their mothers (12.7 +/- 1.4 yr) and in the general population (12.4 +/- 1.2 yr; p <0.05), with a very high incidence of delayed menarche (>2 SD): 16% vs 6.8% (mothers) vs 3.4% (controls) (p <0.01). In conclusion, growth and puberty present unusual patterns in NF1, often with true pathological findings increasing medical and psychological problems.

Body Height↗
PubMed2002

Induction of puberty in the hypogonadal girl--practices and attitudes of pediatric endocrinologists in Europe.

The management of children and adolescents with hypogonadism and in particular the induction of puberty in the hypogonadal girl is subject to controversy. Therefore, under the auspices and through organization of the Drugs and Therapeutics Committee of the European Society of Paediatric Endocrinology (ESPE), an interactive voting session and workshop was held at the 39th ESPE Annual Meeting in Brussels to discuss these topics. Common practice in Europe and attitudes of pediatric endocrinologists in Europe were questioned and recorded in the 1.5-hour program. We now report on some of the results of the questionnaires and discussions of that session to further the discussion on and knowledge of current concepts of induction of puberty in the hypogonadal girl in Europe. It became clear from the data accumulated here that the start of treatment, the aims of therapy and the modalities of how to treat the hypogonadal girl vary amongst pediatric endocrinologists in Europe. For example, a chronological age > or =11 years was considered appropriate for the start of estrogen therapy by 40.4% (out of 188 answers), while 47.8 and 7.5% felt that a chronological age > or =13 and > or =15 years respectively was appropriate. In respect to the form and route of estrogen administration, the audience was asked for their common estrogen replacement practice: 31.9% used oral 17beta-estradiol treatment, while 10% would prescribe 17beta-estradiol transdermal patches. Another 12.2% would recommend conjugated estrogens (e.g. Premarin) orally, 4.8% use oral estradiol valerate and 39.3% ethinylestradiol orally. Only 1.8% out of 229 physicians answering were undecided. In addition, counseling of patients and their families is quite variable and perceptions for example regarding potential pregnancies in affected women are also not uniform. In this report the authors do not want to provide their own personal views but rather reflect current practice in Europe. It is hoped that a more uniform picture will emerge once European and international guidelines on how to treat the girl with hypogonadism will be available and even more discussions amongst doctors from different countries have been led.

Adolescent↗
PubMed2002

High serum allopregnanolone levels in girls with precocious puberty.

Allopregnanolone, a circulating neuroactive steroid hormone, is involved in the modulation of behavioral functions, stress, and the neuroendocrine axis. The aim of this study was to evaluate serum allopregnanolone concentrations in girls with central precocious puberty (n = 12), girls with normal pubertal development at the same pubertal stage (n = 17), and prepubertal girls (age-matched; n = 16). Gonadotropin and steroid hormones (allopregnanolone, cortisol, dehydroepiandrosterone sulfate, and E2) were assessed in all patients. GnRH and ACTH stimulation tests were performed in all girls with central precocious puberty and in some pubertal controls. Basal allopregnanolone levels in girls with central precocious puberty were significantly higher than in normal controls (P < 0.01). Allopregnanolone levels increased significantly after GnRH and ACTH stimulation tests (P < 0.05) both in girls with central precocious puberty and in those with normal pubertal development. There was no difference found between the peak values. In conclusion, our study shows that allopregnanolone is hypersecreted in central precocious puberty, confirming a pubertal stage-related increase in its levels during normal pubertal development. The increase in serum allopregnanolone after GnRH and ACTH stimulation tests demonstrates that both adrenal cortex and gonads are sources of this neuroactive steroid.

Adrenocorticotropic Hormone↗
PubMed2002

Thyroid nodules.

Explore the source record for details and available documents.

Biopsy, Needle↗
PubMed2002

Hypothyroidism.

Explore the source record for details and available documents.

Humans↗
PubMed2002

Association of waist circumference and body mass index with fasting blood insulin in severely obese children: a cross-sectional study.

We tested whether body mass index (BMI) and waist circumference (WC) are associated with fasting insulin in severely obese children. A number of 391 (204 female and 187 male) obese children were consecutively enrolled in the study at a Paediatric outpatient clinic. They were aged 10+/-3 yr (mean+/-SD; range: 3-17 yr) and had a relative weight for age of 160+/-27% (mean+/-SD). BMI and WC explained respectively 9 and 13% of the variance of log-transformed (lt) insulin (p<0.0001 for both). After correction for age, however, BMI lost its association with lt-insulin (p=NS) and WC explained only 3% (p<0.001) of lt-insulin variance. Sex and pubertal status did not influence the relationship between WC, BMI and lt-insulin (p=NS, ANCOVA). We conclude that in severely obese children: 1) WC is a marginally better predictor of fasting blood insulin than BMI, 2) age has a substantial influence on the relationship between BMI, WC and insulin and, 3) the contribution of BMI and WC to insulin is of doubtful clinical relevance because it leaves a substantial portion (> or = 87%) of lt-insulin variance unexplained.

Adolescent↗
PubMed2001

CD20 levels determine the in vitro susceptibility to rituximab and complement of B-cell chronic lymphocytic leukemia: further regulation by CD55 and CD59.

Complement-dependent cytotoxicity is thought to be an important mechanism of action of the anti-CD20 monoclonal antibody rituximab. This study investigates the sensitivity of freshly isolated cells obtained from 33 patients with B-cell chronic lymphocytic leukemia (B-CLL), 5 patients with prolymphocytic leukemia (PLL), and 6 patients with mantle cell lymphoma (MCL) to be lysed by rituximab and complement in vitro. The results showed that in B-CLL and PLL, the levels of CD20, measured by standard immunofluorescence or using calibrated beads, correlated linearly with the lytic response (coefficient greater than or equal to 0.9; P <.0001). Furthermore, the correlation remained highly significant when the 6 patients with MCL were included in the analysis (coefficient 0.91; P <.0001), which suggests that CD20 levels primarily determine lysis regardless of diagnostic group. The role of the complement inhibitors CD46, CD55, and CD59 was also investigated. All B-CLL and PLL cells expressed these molecules, but at different levels. CD46 was relatively weak on all samples (mean fluorescence intensity less than 100), whereas CD55 and CD59 showed variability of expression (mean fluorescence intensity 20-1200 and 20-250, respectively). Although CD55 and CD59 levels did not permit prediction of complement susceptibility, the functional block of these inhibitors demonstrated that they play an important role in regulating complement-dependent cytotoxicity. Thus, lysis of poorly responding B-CLL samples was increased 5- to 6-fold after blocking both CD55 and CD59, whereas that of high responders was essentially complete in the presence of a single blocking antibody. These data demonstrate that CD20, CD55, and CD59 are important factors determining the in vitro response to rituximab and complement and indicate potential strategies to improve the clinical response to this biologic therapy.

Antibodies, Monoclonal↗
PubMed2001

Selective induction of phospholipase D1 in pathogen-activated human monocytes.

Phospholipase D (PLD) activation is part of the complex signalling cascade induced during phagocyte activation. Two PLD isoforms have been cloned, but their role in phagocyte functions is still poorly defined. We report that resting fresh circulating human monocytes expressed PLD1. PLD1 protein expression was rapidly down-regulated during cell culture. Lipopolysaccharide and pathogen-derived agonists (Candida albicans, arabinoside-terminated lipoarabinomannan and Gram-positive bacteria, but not mannose-capped lipoarabinomannan or double-stranded RNA) strongly induced PLD1 expression at both the mRNA and protein levels. Pro-inflammatory cytokines [interleukin (IL)-1beta and tumour necrosis factor alpha] had only a weak effect, whereas immune cytokines (IL-6 and interferon gamma), anti-inflammatory cytokines (IL-13 and IL-10) and chemoattractants (fMet-Leu-Phe and macrophage chemoattractant protein 1) were inactive. None of the agonists tested induced significant changes in the basal expression of PLD2 mRNA. Consistent with PLD1 up-regulation was the observation that PLD enzymic activity was higher in monocytes treated with active-pathogen-derived agonists than in control cells, when stimulated with PMA or with chemotactic agonists (fMet-Leu-Phe and C5a). Thus PLD2 seems to be a constitutive enzyme in circulating monocytes. Conversely, PLD1 is an inducible protein, rapidly regulated during culture conditions and selectively induced during cell activation. Therefore PLD1 might have a relevant role in immune responses against pathogens and in chronic inflammation.

Blotting, Northern↗
PubMed2001

Rhabdomyoma of a rare type in a child: case report and literature review.

We describe a 9-year-old boy who presented with dyspnea and with a neck mass which was initially described as a thyroid nodule. At the end of the diagnostic-therapeutic research this mass was finally diagnosed as an adult rhabdomyoma originating from the mediastinum. This is an extremely rare tumor which is usually found in the adult population.

Child↗
PubMed2001

Leptin inhibits steroid biosynthesis by human granulosa-lutein cells.

Absence of leptin secretion compromises reproductive function and fertility in the ob/ob mouse which, when given leptin, shows a rise in serum LH levels and becomes fertile. Recently, the long and active isoform of the leptin receptor was detected in the ovary, indicating that leptin may also show direct gonad-related activity. To examine this, we studied the effect of graded doses of human leptin on estradiol (E2) and progesterone (P4) concentrations in the culture media of human granulosa-lutein cells obtained from follicular fluid of women undergoing in vitro fertilization. We also evaluated the mRNA expression of steroidogenic acute regulatory protein (StAR), aromatase, and cytochrome P450 17alpha (CYP17) in these cells at baseline and after exposure to leptin. Estradiol levels were significantly decreased in the media 24 hours after incubation of the cells with increasing hLeptin concentrations (10(-11) - 10(-7) mol/l). The maximal 30% decrease in E2 production was caused by the 10(-9) mol/l hLeptin concentration; however, P4 levels in the media were not influenced by leptin. Exposure of granulosa-lutein cells to 10(-9) mol/l hLeptin did not produce any measurable changes on StAR, aromatase, or CYP17 mRNA expression. When hLeptin (10(-9) mol/l) was co-incubated with increasing concentrations of hCG (1.25 - 10 mlU/ml), IGF-II (15-60 ng/ml) or 1-6 desaminated IGF-II (deslGF-II; 15-60 ng/ml), it did not modify the elevation of E2 concentrations caused by each of the different stimuli. We conclude that leptin suppresses E2 secretion by human granulosa-lutein cells but does not impair the stimulatory effects of hCG and IGFs on these cells. Leptin may play a minor, but direct regulatory role on unstimulated human ovarian steroidogenesis by interfering with either the translational or post-translational steps of the baseline CYP17 and/or aromatase synthesis and/or the activation of the enzymes.

Adult↗