Quiste de Tarlov: diagnóstico durante el puerperio / Tarlov cyst: diagnosis during the postpartum period

Los quistes de Tarlov, también llamados quistes extradurales, son una ectasia del espacio perineural de las raíces nerviosas espinales, situadas de manera habitual distalmente al ganglio dorsal o en la unión con este. Su localización más frecuente es la región sacra y son de etiología incierta. La mayoría de las veces son asintomáticos, aunque pueden ser responsables de síntomas irritativos lumbares o radiculares. A continuación se presenta un caso clínico de un quiste de Tarlov que se manifiesta con síntomas radiculares durante el puerperio

Tarlov cysts, also called extradural cysts, consist of perineural space ectasia of the spinal nerve roots, usually located distal to the dorsal root ganglia or in the junction with this structure. The most frequent location is in the sacral region. The etiology remains uncertain. Most Tarlov cysts are asymptomatic, but they can cause lumbar or root irritative symptoms1. We describe a case of Tarlov cyst presenting as radicular symptoms during the postpartum period

Effect of Mouriri pusa tannins and flavonoids on prevention and treatment against experimental gastric ulcer.

AIM OF THE STUDY: Mouriri pusa, popularly known as "manapuçá" or "jaboticaba do mato", is a plant from Brazilian cerrado that has been found to be commonly used in the treatment of gastrointestinal disturbs in its native region. The present work was carried out to investigate the effect of tannins (TF) and flavonoids (FF) fractions from Mouriri pusa leaves methanolic extract on the prevention and cicatrisation process of gastric ulcers, and also evaluate possible toxic effects. MATERIALS AND METHODS: The following protocols were taken in rats: acute assay, in which ulcers were induced by oral ethanol after pre-treatment with the fractions; and 14 days treatment assay, in which ulcers were treated for 14 days after induction by local injection of acetic acid. RESULTS: In the acute model, treatment with either, TF (25mg/kg) or FF (50mg/kg), was able to reduce lesion area, showing gastroprotective effect. In addition, FF proved itself anti-inflammatory by reducing COX-2 levels. In acetic acid model, both fractions exhibited larger ulcers' regenerative mucosa, indicating cicatrisation enhancement. FF group also showed augmented cell proliferation, anti-inflammatory action and enhanced angiogenesis as well as increased mucus secretion. Moreover, concerning the toxicity parameters analyzed, no alteration in the fractions groups was observed. CONCLUSIONS: Tannins and flavonoids from Mouriri pusa provide beneficial effects against gastric ulcers with relative safety.

Mutagenicity of Mouriri pusa Gardner and Mouriri elliptica Martius.

Mouriri pusa Gardner and Mouriri elliptica Martius are fruit-bearing plants of the Melastomataceae family, popularly known in Brazil as puçá-preto or jaboticaba-do-cerrado, and they are used in folk medicine for the treatment of gastric ulcers. In this study, we employ the Ames test to assess the mutagenicity of compounds obtained from the leaves of these species. The methanol extract of the M. pusa was mutagenic to the Salmonella typhimurium strains TA98, TA97a and TA100, with or without metabolic activation. The methanol extract of M. elliptica induced mutagenic activity in TA98 when metabolized with S9 fraction and TA97a with and without S9, but with lower mutagenicity index (MI) and potencies values than those for M. pusa. Enriched fractions of flavonoids and tannins of M. pusa were also evaluated and they demonstrated positive mutagenicity. The highest values of MI and potency were obtained with the flavonoid fraction, which contains large amounts of quercetin, quercetin glycosides and myricetin. These compounds are probably related to the mutagenicity observed in the Ames test. The dichloromethane extract was not mutagenic in any of the test conditions employed.

Differences in gastroprotective and mutagenic actions between polar and apolar extracts of Ananas ananassoides.

Several plants are used in folk medicine to treat gastrointestinal disorders. Ananas ananassoides (Baker) L.B. Smith (Family Bromeliaceae) is a medicinal plant commonly used in the central region of Brazil against gastric pain. We evaluated two extracts (methanol [MeOH] and dichloromethane [DCM]) obtained from the leaves of A. ananassoides for their ability to protect the gastric mucosa against injuries caused by necrotizing agents (0.3 M HCl/60% ethanol, absolute ethanol, non-steroidal anti-inflammatory drugs, and pylorus ligation) in mice and rats. The best results were obtained after pretreatment with the DCM extract, whereas the MeOH extract did not show any significant anti-ulcerogenic activity but presented mutagenic action. The mechanism of action of the DCM extract suggested the effective participation of endogenous sulfhydryl group in the gastroprotective action. The data, taken together with the absence of acute toxicity and mutagenicity, indicate the apolar extract, instead of the polar, extract of A. ananassoides as a safe and potential new anti-ulcerogenic drug.

Studies of gastric mucosa regeneration and safety promoted by Mouriri pusa treatment in acetic acid ulcer model.

ETHNOPHARMACOLOGICAL RELEVANCE: Mouriri pusa Gardn. (Melastomataceae) is a medicinal plant commonly used by people living in the Cerrado to treat gastrointestinal disturbances. This medicinal plant has shown intense gastroprotective action in rodent gastric lesion, but still there are no data about its healing effect on gastric mucosa. AIM OF THE STUDY: To evaluate the methanolic extract (MeOH) obtained from Mouriri pusa leaves for its effect on the cicatrisation process of gastric ulcer. MATERIALS AND METHODS: The healing effects on gastric ulcers inducted by subserosal injection of acetic acid were evaluated by macroscopic and microscopic measures, immunohistochemistry and cell counting in rats treated with MeOH extract of Mouriri pusa (250 mg/kg, p.o./daily) for 14 or 30 days. The toxicity of Mouriri pusa was also evaluated by body and organ weight measure and clinical biochemical parameters. RESULTS: Mouriri pusa treatments lasting 14 and 30 days showed elevated mucus secretion (PAS) and thicker regenerative gastric mucosa, denoting increased cell proliferation, which was confirmed by PCNA immunohistochemical analysis. Moreover, there was important cell recruitment (neutrophils and mast cells) to the site of the ulcer, which is an important factor in ulcer healing. No toxic effect was observed in all parameters evaluated. Phenolic compounds present in the MeOH extract like tannins, flavonoids and epicatechin are the probable agents involved in the healing effects of this medicinal plant. CONCLUSIONS: These findings showed a potential effect of Mouriri pusa in increasing regeneration of damaged gastric mucosa with safety for human use.

Hypothalamo-hypophysial dysfunction after traumatic brain injury in children and adolescents: a preliminary retrospective and prospective study.

With two study protocols, one retrospective and the other prospective, we evaluated hypothalamo-hypophysial dysfunction (HHD) in paediatric patients treated for traumatic brain injury (TBI) in the neurosurgical or intensive care department at our hospital. The retrospective group comprised 22 patients who had experienced TBI 0.7-7.25 years before the study. The prospective group included 30 patients assessed at TBI (T0), 26 of 30 after 6 months (T6), and 20 of 26 after 12 months (T12). Auxological and hormonal basal parameters of hypothalamo-hypophysial function were evaluated at recall in the retrospective group, and at T0, T6 and T12 in the prospective group. Basal data and standard dynamic tests in selected patients revealed one with precocious puberty, one with total anterior hypopituitarism, one with central hypogonadism, and one with growth hormone (GH) deficiency in the retrospective group; three patients with cerebral salt-wasting syndrome, one with diabetes insipidus and seven with low T3 syndrome at T0 (all transient), one with hypocorticism at T6 confirmed at T12, and one with GH deficiency at T12 in the prospective group. The results of our study show that post-TBI HHD in our paediatric cohort is not uncommon. Of the 48 patients who underwent a complete evaluation (22 retrospective study patients and 26 prospective study patients evaluated at T6) five (10.4%) developed HHD 6 months or more after TBI. HHD was newly diagnosed in one previously normal patient from the prospective group at 12 months after TBI. GH deficiency was the most frequent disorder in our paediatric cohort.

Morphometry and Histochemistry of the Rectus abdominis Muscle Fibers of Tufted Capuchin Monkeys (Cebus apella Linnaeus, 1758) / Morfometría e Histoquímica de las Fibras del Músculo Recto del Abdomen del Mono Capuchino Almohadillado (Cebus apella Linnaeus, 1758)

The phylogenetic proximity of primates to humans, along with their behavioral, biochemical, and anatomical similarities, make such animals more interesting experimental models for biomedical researches, as compared to classical laboratory animals. Another aspect that has called the attention of researchers is the differentiated quadrupedalism present in some primates. The tufted capuchin monkey uses the ground and tree branches as its support for locomotion, showing various postures while performing this task. On the basis of this information, we have decided to study the rectus abdominis muscle of the tufted capuchin monkey, with the following goals: the frequency and area of fiber types; its possible compartmentalization; and identify if this muscle is better adapted to phasic or postural activities. To do this, samples were removed from 4 regions of the rectus abdominis muscle of 6 adult male tufted capuchin monkeys, and were submitted to reaction with m-ATPase, (with alkaline and acid pre-incubation), NADH, and H.E.. Results showed: a statistically significant difference (P<0.05) for both frequency and area, between fiber types FG and FOG and FG and SO, but did not show a statistically significant difference between fibers FOG and SO, in all studied regions; similarity in frequency and area of a same fiber type (FG, FOG, and SO) among the studied regions. Based on these data, it was concluded that: the rectus abdominis muscle of the tufted capuchin monkey does not show fiber compartmentalization, since the distribution and size patterns of the different fiber types are similar in the studied regions; there is a predominance of fast twitch fibers (FG + FOG) over slow twitch fibers (SO), for frequency and area, which characterizes the muscle as being more dedicated to phasic than to postural activities.

La proximidad filogenética y las semejanzas de comportamiento, bioquímicos y anatómicos, de los primates con los humanos convierten a estos animales en modelos experimentales más interesantes para las investigaciones biomédicas, que los animales clásicos de laboratorio. Otro aspecto que ha llamado la atención de los investigadores es el movimiento cuádruple diferente que presentan algunos primates. El macado clavo se traslada usando como apoyo el suelo y las ramas de los árboles, presentando posturas variadas en la ejecución de esas tareas. En base a estas informaciones se resolvió estudiar el músculo recto del abdomen del macaco-clavo, con los siguientes objetivos: observar la frecuencia y el área de los tipos de fibras de este músculo; observar posibles diferencias entre e1las y sus regiones media proximal y distal; y su participación en la locomoción de este animal. Para ello, fueron retiradas 4 muestras de 4 regiones del músculo recto del abdomen, de 6 macacos-clavos machos adultos, que fueron sometidos a las reacciones de m-ATPasa (previa incubaciones alcalina y ácida), NADH y HE. Los resultados mostraron: diferencias estadísticamente significativas (p<0,05) tanto en la frecuencia como en el área, entre las fibras del tipo FG y FOG y FG y SO, pero no presentaron diferencias estadísticamente significativas entre las fibras FOG y SO, en todas las regiones estudiadas. Basándome en estos datos, se concluye que el músculo recto del abdomen del macaco-clavo no presenta división de sus fibras, pues los patrones de distribución y tamaño de los diferentes tipo de de fibras son semejantes en las regiones estudiadas con predominio de las fibras de contracción rápida (FG + FOG) sobre aquellas de contracción lenta (SO), tanto en la frecuencia como en el área, caracterizándolo como un músculo más adaptado para las actividades sutiles que posturales.

Molecular mechanisms of PKCalpha localization and activation by arachidonic acid. The C2 domain also plays a role.

Arachidonic acid, one of the major unsaturated fatty acids released during cell stimulation, participates in the signaling necessary for activation of different enzymes, including protein kinase C (PKC). Here, we demonstrate that arachidonic acid is a direct activator of PKCalpha, but needs the cooperation of Ca(2+) to exert its function. By using several mutants of the C2 and C1 domains, we were able to determine the molecular mechanism of this activation. More specifically, site-directed mutagenesis in key residues found in the C2 domain showed that the Ca(2+)-binding region was essential for the arachidonic acid-dependent localization and activation of PKCalpha. However, the lysine-rich cluster, also located in the C2 domain, played no relevant role in either the membrane localization or activation of the enzyme. Moreover, site-directed mutagenesis in key residues placed in the C1A and C1B subdomains, which are responsible for the diacylglycerol/phorbil ester interaction, demonstrated that the C1A subdomain was involved in the membrane localization and activation mechanism. Taken together, these data suggest a very precise mechanism for PKCalpha activation by arachidonic acid, involving a sequential model of activation in which an increase in intracytosolic Ca(2+) leads to the interaction of arachidonic acid with the Ca(2+)-binding region; only after this step, does the C1A subdomain interact with arachidonic acid, leading to full activation of the enzyme.

Endocrine function and water metabolism in children and adolescents with surgically treated intra/parasellar tumors.

Hydroelectrolytic disorders often complicate surgery of intra/parasellar tumors in children and adolescents. Eighteen patients undergoing microneurosurgical procedures for intra-supra-sellar craniopharyngioma (10 patients), hypothalamic germinomas (3 patients), hypothalamic-chiasmatic astrocytomas (3 patients), pituitary adenomas (2 patients) were studied. The hydroelectrolytic balance was assessed from 8 hours before surgery to 1 week after with a specific protocol in which water metabolism alterations were treated with standard procedure. Diabetes insipidus (DI) was observed in 10/18 patients before surgery and in 15/18 patients after surgery; during surgery it was effectively treated with synthetic desmopressin (DDAVP) and hydroelectrolytic solutions. Hyponatremia, isolated or associated (with diuresis contraction or polyuria), seen during surgery and in the following 24 hours, was treated with variation of the infusion rate. We show that close monitoring and treatment of hydroelectrolytic disorders in patients submitted to neurosurgery for intra/ parasellar tumors may significantly reduce their morbidity and mortality rate.

Pubertal development in patients with McCune-Albright syndrome or pseudohypoparathyroidism.

Gain or loss of function mutations of the GNAS1 gene lead to McCune-Albright syndrome (MAS) or pseudohypoparathyroidism Ia (PHP-Ia), respectively. Patients with MAS, caused by a post-zygotic missense mutation leading to constitutive activation of Gs alpha, suffer from gonadotropin-independent precocious puberty, and delayed or incomplete sexual development and reproductive dysfunction is found in women with PHP-Ia, an inherited disorder caused by deficient expression or function of the Gs alpha protein. In females with MAS, 50% developed precocious puberty by the age of 4 years, the remaining between 4 and 8 years. Peripheral precocious puberty is often atypical and characterized by alternate periods of rapid progression and regression of pubertal development; menstrual bleeding may occur before breast development. Ovarian cyst growth and regression is often described as a sign of ovarian follicle hyperactivation. Notwithstanding this clinical heterogeneity, a subset of patients with MAS develop relentlessly progressive precocious puberty ultimately resulting in premature epiphyseal fusion and reduced adult stature. Long-term information on reproductive function has been obtained in females: some patients had regular menses without ovarian cysts on pelvic US scan, whereas others were oligomenorrheic and showed recurrent ovarian cysts. In males with MAS, precocious puberty occurred in three patients between 4 and 9 years of age. In one patient, long-term follow-up demonstrated normal plasma testosterone and gonadotropin values at the age of 17 years. On testicular sonography, multiple hyperechogeneic spots were found in both testicles (snow-storm appearance). Female patients with PHP-Ia were oligomenorrheic or amenorrheic; more than half had delayed or incomplete sexual development, They were mildly hypoestrogenic with normal to slightly elevated serum gonadotropin levels. These clinical and biochemical findings indicate partial resistance of the theca and granulosa cells of the ovary to gonadotropins due to deficient Gs alpha activity. Responsiveness might be sufficient to promote some degree of follicular development and steroid secretion, but insufficient to induce ovulation

Impact of endocrine hyperfunction and phosphate wasting on bone in McCune-Albright syndrome.

Skin dysplasia, as café-au-lait spots, bone fibrous dysplasia and peripheral endocrinopathies are the main clinical features of McCune-Albright syndrome (MAS). This illness is due to activating mutations of the Gsalpha protein and is spread with a mosaic pattern in affected tissues that consist of intermixed areas of normal and mutated cells. Peripheral endocrine secretion, free of hypothalamic pituitary control, is the hallmark of the endocrine syndromes: precocious puberty, Cushing's syndrome, hyperthyroidism and gigantism/acromegaly. In addition, phosphate wasting as hyperphosphaturia is often present. The impact of hormonal hypersecretion and phosphate loss on the bones of patients with MAS is poorly understood both in normal and fibrous bone tissue. As hypercortisolism and hyperthyroidism increase bone resorption, hyperestrogenism and growth hormone hypersecretion stimulate bone growth and mineralization, and phosphate wasting reduces bone mineral content. All these actions can be exerted at varying times and degrees in a single patient on lesional and non-lesional bones. Sonographic evidence of multiple diffused hyperechogenic spots in the testes of patients with MAS do not seem to be related to alterations in calcium-phosphate metabolism but rather to zonal dysplasia/hyperplasia of testicular tissue.

Pamidronate treatment in bone fibrous dysplasia in children and adolescents with McCune-Albright syndrome.

Thirteen patients with McCune-Albright syndrome (MAS) and bone fibrous dysplasia (BFD) have been treated for 2-6 years with pamidronate, an aminobisphosphonate which inhibits osteoclastic function. MAS is a rare genetic condition caused by constitutive activating mutations of the Gs protein and manifests with skin dysplasia, bone fibrous dysplasia, and multiple endocrinopathies. Raised serum alkaline phosphatase and urinary hydroxyproline have been reported in these patients, indicating bone metabolic hyperactivity. Encouraging therapeutic results have been achieved with pamidronate, mainly in adults. In our study, treatment reduced bone pain, fracture rate and metabolic indices of bone turnover, in particular significantly decreased bone alkaline phosphatase and cross-links (Wilcoxon test; p <0.06), and increased bone mineral density (DEXA). Signs of healing, such as thickening of the cortical bone, were found in some patients. Three patterns of MRI were found: homogeneous hypointense fibrous tissue, 'dotted' hypointense fibrous tissue, and hyperintense cystic images. Pamidronate treatment can be considered a favorable therapeutic option for patients with MAS.

Bone turnover in children and adolescents with McCune-Albright syndrome treated with pamidronate for bone fibrous dysplasia.

Bone fibrous dysplasia is one of the main features of McCune-Albright syndrome, a rare genetic condition caused by constitutive activating mutations of Gs-protein and defined by skin dysplasia, bone fibrous dysplasia, and autonomous multiple endocrinopathies. Raised serum alkaline phosphatase (ALP) and urinary hydroxyproline levels indicating bone metabolic hyperactivity have been reported in these patients. Encouraging therapeutic results have been achieved, mainly in adults, with pamidronate, an aminobisphosphonate. In this study we investigate newer bone metabolic indices in a cohort of 11 children and adolescents treated with pamidronate. Tenfold increases of bone ALP and urinary pyridinoline cross-links were found and osteocalcin levels were twofold higher compared with reference values. After treatment, significant decreases in bone ALP and cross-links (Wilcoxon test P < 0.06) were found. Bone mineral density (BMD) significantly increased during treatment. There were signs of radiological healing as thickening of the cortical bone was found in some cases.

Identification of the phosphatidylserine binding site in the C2 domain that is important for PKC alpha activation and in vivo cell localization.

The C2 domain of classical PKCs binds to membranes through Ca(2+) bridging to phosphatidylserine as recently observed through X-ray diffraction of the isolated domain. Additionally, it has been proposed that N189, T251, R216, and R249A interact directly with phosphatidylserine [Verdaguer, N., et al. (1999) EMBO J. 18, 6329-6338]. When these four residues were mutated to Ala to determine their role in PKC binding to phospholipid membranes, PKC activation, and in its in vivo localization, the results revealed that they were very important for the activation of full-length PKCalpha. N189, in particular, was involved in the activation of the enzyme after its interaction with PS, since its mutation to Ala did not decrease the level of membrane binding but did prevent full enzyme activation. On the other hand, mutations R216A, R249A, and T251A affected both membrane binding and enzyme activation, although T251A had the most drastic effect, suggesting that the protein interactions with the carbonyl groups of the phospholipid are also a key event in the activation process. Taken together, these results show that the four residues located near the calcium binding site are critical in phosphatidylserine-dependent PKCalpha activation, in which N189 plays an important role, triggering the enzyme activation probably by interacting with neighboring residues of the protein when lipid binding occurs. Furthermore, these results provide strong evidence for better defining one of the two phosphatidylserine isomer models proposed in the previous crystallographic report.

Accuracy of fine needle aspiration biopsy of thyroid nodules in detecting malignancy in childhood: comparison with conventional clinical, laboratory, and imaging approaches.

In childhood the traditional diagnostic approach to thyroid nodules consists of clinical, laboratory, and imaging evaluations. A safe and accurate procedure is needed to promptly identify patients who require surgery. In regard to the usefulness of fine needle aspiration biopsy, the data in the literature concerning children and adolescents are scanty. The aim of this study was to evaluate and compare the diagnostic accuracies of clinical, laboratory, and imaging data collected retrospectively in a group of pediatric patients with thyroid nodules submitted to fine needle aspiration biopsy. Forty-two patients who underwent surgery for thyroid nodules, recruited in 9 Italian pediatric endocrine units, were retrospectively studied. According to histological diagnosis, they were divided into 2 groups, 22 patients with benign lesions and 20 patients with malignant lesions. From clinical records we obtained data about 1) symptoms of neck compression; 2) cervical adenopathy; 3) thyroid function, calcitonin level, and antithyroid antibody titers; 4) ultrasonography; 5) (99m)Tc scintiscanning; and 6) cytology obtained with fine needle aspiration biopsy. Patients and nodule characteristics were analyzed statistically for associations with the presence of thyroid cancer. Among clinical findings, only adenopathy was significantly higher in the group with cancer (8 of 22 benign lesions vs. 16 of 20 malignant lesions; P = 0.006). Thyroid function and antibody titers were similar in the 2 groups, whereas the serum calcitonin level was elevated only in 1 patient with malignant lesions. Among ultrasonography findings, no significant statistical difference was found between the 2 groups with regard to number, dimensions, growth progression, or hypoechogenic pattern of the nodules. Regarding scintigraphic findings, no significant difference was found between the 2 groups. However, a positive correlation (r = 0.90; P < 0.0001) was found between fine needle aspiration biopsy cytological findings and histological diagnoses. The sensitivity, specificity, and accuracy of fine needle aspiration biopsy were 95%, 86.3%, and 90.4%, respectively. A multiple regression analysis showed that only fine needle aspiration biopsy (beta coefficient = 0.963; P < 0.0001) significantly contributed to detecting malignancy (multiple r = 0.973; P < 0.0001). This study provides strong evidence that fine needle aspiration biopsy is a safe technique even in childhood and adolescence, offering the best sensitivity, specificity, and accuracy in detecting malignancy compared with conventional approaches.

Thyroid diseases in patients treated during pre-puberty for medulloblastoma with different radiotherapic protocols.

We evaluated thyroid disease in 32 patients treated, during pre-puberty, for medulloblastoma, followed for at least 4 years and without relapse during observation. After surgery the patients underwent chemotherapy (CT) and radiotherapy (RT). The protocols were as follows: 20 patients (group A) SNC 76 and SNC 85 protocols which included conventional fractionated RT (36-40 Gy to the craniospinal axis and a 14-18 Gy boost to the posterior fossa, administered as 1.5-1.8 Gy per fraction per day) and a junction between the cranial and the spinal fields at C2-C3 level; 12 patients (group B) SNC 91 protocol which included hyperfractionated RT (36 Gy to the craniospinal axis and a 30 Gy boost to the posterior fossa; this was administred as 1 Gy per fraction twice per day) and a junction at levels C5-C6 or C6-C7 level. The mean age at diagnosis was 7.4+/-3.2 years for group A and 8.4+/-2.6 years for group B. Thyroid function was evaluated yearly and ultrasonographic characteristics every 2 years. The patients were followed for a mean of 10.8+/-3.8 for group A and 6+/-1.4 years for group B. Primary hypothyroidism was diagnosed in 16 group A patients and 4 group B patients, and central hypothyroidism was diagnosed in 2 group A patients (difference in risk of developing hypothyroidism evaluated with a Wilcoxon-test: p=0.048). Ultrasonography showed reduced thyroid volume in 7 group A cases, and structural changes in 21 patients (17 group A, 4 group B); 9 L-thyroxine-treated patients were confirmed hypothyroid after having stopped therapy. A thyroid nodule was detected in two cases (one from each group). In conclusion, our data indicate that thyroid injury may be diminished by the use of hyperfractionation and low-junction radiotherapy in the treatment of medulloblastoma.

GH/IGF-I axis in Prader-Willi syndrome: evaluation of IGF-I levels and of the somatotroph responsiveness to various provocative stimuli. Genetic Obesity Study Group of Italian Society of Pediatric Endocrinology and Diabetology.

Basal IGF-I levels and the GH response to at least two among provocative stimuli such as clonidine (CLO, Catapresan, 150 mcg/m2 p.o.), GHRH (1 mcg/kg i.v.)+arginine (ARG, 0.5 g/kg i.v. infusion during 30 min) and GHRH+pyridostigmine (PD, Mestinon cpr 60 mg p.o.) have been evaluated in 43 children with Prader-Willi syndrome (PWS, 17 males and 26 females, age 3-22 yr, 7 normal weight and 36 obese PWS), in 25 normal short children (NC, 17 males and 8 females, 7.7-18.5 yr) and in 24 children with simple obesity (OB, 14 males, 10 females, 7.7-21.5 yr). Both normal weight and obese PWS had mean IGF-I levels lower than those recorded in NC (p<0.001) and OB (p<0.001). The GH responses to GHRH+ARG and GHRH+PD in NC were similar and higher than that to CLO (p<0.001). In PWS the GH response to GHRH+ARG was higher than that to GHRH+PD (p<0.001) which, in turn, was higher than that to CLO (p<0.001); these responses in PWS were lower than those in normal children (p<0.02) and similar to those in OB. In normal weight PWS the GH responses to GHRH+ARG and to GHRH+PD were similar and higher than to CLO (p<0.05); however, each provocative stimulus elicited a GH rise lower than that in NC (p<0.05). In obese PWS as well as in OB the GH response to GHRH+ARG was higher than that to GHRH+PD (p<0.02) which, in turn, was higher than that to CLO (p<0.001); all GH responses in obese PWS and OB were lower than those in NC (p<0.001) but similar to those in normal weight PWS. In conclusion, patients with PWS show clear reduction of IGF-I levels as well as of the somatotroph responsiveness to provocative stimuli independently of body weight excess. These results strengthen the hypothesis that PWS syndrome is frequently connotated by GH insufficiency.