Intensive care management of patients with viral encephalitis.

Viral encephalitis is a severe syndrome that can lead to encephalopathy, seizures, focal deficits, and neurological sequelae and death. It is mainly caused by neurotropic herpes viruses (i.e., HSV and VZV), although other pathogens may be observed in specific geographic regions or conditions. Recent advances in neuroimaging and molecular biology (PCR, metagenomics) allow for faster and more accurate etiological diagnoses, although their benefits need to be confirmed to provide guidelines for their use and interpretation. Despite intravenous acyclovir therapy and supportive care, outcomes remain poor in about two-thirds of herpes encephalitis patients requiring ICU admission. Randomized clinical trials focusing on symptomatic measures (i.e. early ICU admission, fever control, and treatment of seizures/status epilepticus) or adjunctive immunomodulatory therapies (i.e. steroids, intravenous immunoglobulins) to improve neurologic outcomes have not been conducted in the ICU setting. Large prospective multicenter studies combining clinical, electrophysiological, and neuroimaging data are needed to improve current knowledge on care pathways, long-term outcomes, and prognostication.

3D reconstructions, 4D imaging and postprocessing with CT in musculoskeletal disorders: Past, present and future.

Three-dimensional (3D) imaging and post processing are common tasks used daily in many disciplines. The purpose of this article is to review the new postprocessing tools available. Although 3D imaging can be applied to all anatomical regions and used with all imaging techniques, its most varied and relevant applications are found with computed tomography (CT) data in musculoskeletal imaging. These new applications include global illumination rendering (GIR), unfolded rib reformations, subtracted CT angiography for bone analysis, dynamic studies, temporal subtraction and image fusion. In all of these tasks, registration and segmentation are two basic processes that affect the quality of the results. GIR simulates the complete interaction of photons with the scanned object, providing photorealistic volume rendering. Reformations to unfold the rib cage allow more accurate and faster diagnosis of rib lesions. Dynamic CT can be applied to cinematic joint evaluations a well as to perfusion and angiographic studies. Finally, more traditional techniques, such as minimum intensity projection, might find new applications for bone evaluation with the advent of ultra-high-resolution CT scanners. These tools can be used synergistically to provide morphologic, topographic and functional information and increase the versatility of CT.

CT arthrography of the intra-articular long head of biceps tendon: Diagnostic performance outside the labral-bicipital complex.

PURPOSE: The purpose of this study was to determine the performance of CT arthrography for the diagnosis of intra-articular long head of biceps (LHB) tendon intrinsic lesions using arthroscopy findings as standard of reference. MATERIAL AND METHODS: CT arthrography studies of 98 patients (55 men, 43 women; mean age 54.8±12.7 [SD] years [range: 16-77 years]) were retrospectively evaluated by two radiologists independently. Per operative arthroscopic images and surgical reports were retrospectively reviewed by a shoulder-specialist surgeon. Based on the analysis of arthroscopic images and the surgical reports, the LHB tendon was classified as normal (continuous with uniform tendon thickness), tendinopathy/partial rupture (focal change in tendon thickness and contour irregularities) and total rupture (total loss in tendon continuity). Imaging results were compared to those of surgery that served as standard of reference. Interobserver agreement was assessed. RESULTS: At arthroscopy, the LHB tendon was classified as normal in 38/98 (38.8%) patients, tendinopathic in 51/52 (52%) and totally ruptured in 9/98 (9.2%). The sensitivity and specificity of CT arthrography for the diagnosis of LHB tendinopathy were respectively 74% (95%CI: 60%-85%) and 93% (95%CI: 80%-99%) for reader 1 and 79% (95% CI: 67%-89%) and 95% (95% CI: 83%-99%) for reader 2. The sensitivity and specificity for the diagnosis of LHB tendon total ruptures were 100% (95%CI: 66%-100%) and 93% (95%CI: 86%-98%) for both readers. Interobserver agreements for the identification of the LHB tendon tendinopathy and total ruptures were excellent (kappa values of 0.94 and 0.96, respectively). CONCLUSION: CT arthrography demonstrates good sensitivity and excellent specificity for the detection of intra-articular LHB tendinopathy and tear.

Functional outcomes in adult patients with herpes simplex encephalitis admitted to the ICU: a multicenter cohort study.

PURPOSE: We aimed to study the association of body temperature and other admission factors with outcomes of herpes simplex encephalitis (HSE) adult patients requiring ICU admission. METHODS: We conducted a retrospective multicenter study on patients diagnosed with HSE in 47 ICUs in France, between 2007 and 2017. Fever was defined as a body temperature higher or equal to 38.3 °C. Multivariate logistic regression analysis was used to identify factors associated with poor outcome at 90 days, defined by a score of 3-6 (indicating moderate-to-severe disability or death) on the modified Rankin scale. RESULTS: Overall, 259 patients with a score on the Glasgow coma scale of 9 (6-12) and a body temperature of 38.7 (38.1-39.2) °C at admission were studied. At 90 days, 185 (71%) patients had a poor outcome, including 44 (17%) deaths. After adjusting for age, fever (OR = 2.21; 95% CI 1.18-4.16), mechanical ventilation (OR = 2.21; 95% CI 1.21-4.03), and MRI brain lesions > 3 lobes (OR = 3.04; 95% CI 1.35-6.81) were independently associated with poor outcome. By contrast, a direct ICU admission, as compared to initial admission to the hospital wards (i.e., indirect ICU admission), was protective (OR = 0.52; 95% CI 0.28-0.95). Sensitivity analyses performed after adjustment for functional status before admission and reason for ICU admission yielded similar results. CONCLUSIONS: In HSE adult patients requiring ICU admission, several admission factors are associated with an increased risk of poor functional outcome. The identification of potentially modifiable factors, namely, elevated admission body temperature and indirect ICU admission, provides an opportunity for testing further intervention strategies.

Correction to: Functional outcomes in adult patients with herpes simplex encephalitis admitted to the ICU: a multicenter cohort study.

The original article unfortunately contained a mistake. Due to technical problems the study group was not tagged correctly. Please find the correct tagging down below. We apologize for the mistake.

Desmopressin test during petrosal sinus sampling: a valuable tool to discriminate pituitary or ectopic ACTH-dependent Cushing's syndrome.

UNLABELLED: Corticotropin-releasing hormone (CRH)-stimulated petrosal sinus sampling is currently the gold standard method for the differential diagnosis between pituitary and ectopic ACTH-dependent Cushing's syndrome. Our objective was to determine sensitivity and specificity of desmopressin test during petrosal sinus sampling. PATIENTS AND METHODS: Forty-three patients had petrosal sinus sampling because of the lack of visible adenoma on magnetic resonance imaging (MRI) and/or because of discordant cortisol response to high-dose dexamethasone suppression test. ACTH sampling was performed in an antecubital vein, right and left petrosal sinuses, then at each location 5 and 10 min after injection of desmopressin. Diagnosis was based on the ACTH ratio between petrosal sinus and humeral vein ACTH after desmopressin test. Diagnosis was confirmed after surgery. A receiver operating characteristics curve was used to determine optimal sensitivity and specificity. RESULTS: Thirty-six patients had Cushing's disease (CD) and seven had ectopic ACTH secretion. A ratio > 2 after desmopressin was found in 35 of the 36 cases of CD (sensitivity: 95%). A ratio < or = 2 was found in the seven patients with ectopic ACTH secretion (specificity: 100%). Sinus sampling was ineffective in determining the left or right localization of the adenoma (sensitivity = 50%). No major adverse effects were observed during or after the procedure. CONCLUSION: Desmopressin test during petrosal sinus sampling is a safe and effective diagnostic procedure in ACTH-dependent Cushing's syndrome. It thus represents a valuable alternative to CRH.

Gamma knife radiosurgery is a successful adjunctive treatment in Cushing's disease.

OBJECTIVE: Though transsphenoidal surgery remains the first-line treatment of Cushing's disease, recurrence occurs frequently. Conventional radiotherapy and anticortisolic drugs both have adverse effects. Stereotactic radiosurgery needs to be evaluated more precisely. The aim of this study was to determine long-term hormonal effects and tolerance of gamma knife (GK) radiosurgery in Cushing's disease. DESIGN: Forty patients with Cushing's disease treated by GK were prospectively studied over a decade, with a mean follow-up of 54.7 months. Eleven of them were treated with GK as a primary treatment. METHODS: Radiosurgery was performed at the Department of Functional Neurosurgery of Marseille, France, using the Leksell Gamma Unit B and C models. Median margin dose was 29.5 Gy. Patients were considered in remission if they had normalized 24-h free urinary cortisol and suppression of plasma cortisol after low-dose dexamethasone suppression test. RESULTS: Seventeen patients (42.5%) were in remission after a mean of 22 months (range 12-48 months). The two groups did not differ in terms of initial hormonal levels. Target volume was significantly higher in uncured than in remission group (909.8 vs 443 mm(3), P = 0.038). We found a significant difference between patients who were on or off anticortisolic drugs at the time of GK (20 vs 48% patients in remission respectively, P = 0.02). CONCLUSION: With 42% of patients in remission after a median follow-up of 54 months, GK stereotactic radiosurgery, especially as an adjunctive treatment to surgery, may represent an alternative to other therapeutic options in view of their adverse effects.

Prolactinoma surgery.

Surgery is generally used as second-line treatment in prolactinomas. For microprolactinomas, it may be indicated in cases of resistance or intolerance to dopamine agonists or where patients prefer definitive cure to lifelong drug treatment. In highly trained hands, selective adenomectomy results in normalization of prolactin levels in 75-90% of cases with little morbidity and no mortality. However, subsequent relapse is possible in up to 20% of cases. In macroprolactinoma, a definitive cure is unlikely due to the frequency of invasive tumor extension. A transsphenoidal or, less frequently, a transfrontal surgical approach is necessary in patients resistant to or intolerant of medical treatment, and also in rare cases such as pituitary apoplexy or cerebrospinal fluid rhinorrhea.

[Diagnostic value of autoantibodies to MAG by ELISA Bühlmann in 117 immune-mediated peripheral neuropathies associated with monoclonal IgM to SGPG/SGLPG]. / Les autoanticorps IgM anti-MAG par Elisa Bühlmann: apport diagnostique dans 117 neuropathies périphériques auto-immunes associées à une IgM monoclonale à activité anti-SGPG/SGLPG.

The neuropathies associated with monoclonal IgM gammopathy reacted with glycoconjugated targets on a very antigenic epitope on the sulfated glucuronic glycolipids corresponding to SGPG and SGLPG (sulfoglucuronyl paragloboside and sulfoglucuronyl lactosaminyl paragloboside), myelin-associated glycoprotein (MAG) and sulfatide. Sometimes monoclonal IgM binds to a broad spectrum of gangliosides. The detection of targets of autoantibodies has considerable importance in the diagnosis and management of patients. It is not known whether the results of antibody tests are equally sensitive and specific for identification of involved auto-antigens. In this study we evaluated the results obtained using IgM reactivity against MAG by enzyme-linked immunosorbent assay (ELISA Bühlmann) with IgM reactivity against SGPG/SGLPG obtained by overlay thin-layer chromatography. We selected 117 patients with anti-SGPG/SGLPG monoclonal gammopathy and peripheral neuropathy and a control group of 102 peripheral neuropathies with 24 having IgM high titres of monoclonal IgM anti-ganglioside antibodies. The anti-MAG sensitivity was 0.97, specificity was 0.86. There is a crossreactivity between 8 (57%) monoclonal IgM antibodies anti-MAG and anti-ganglioside GM1 and 2 (28%) anti-disialylated gangliosides. These results indicate that in clinical practice, anti-MAG ELISA is useful for eliminating anti-MAG neuropathy, as well as for positive diagnosis for titres upper than 10,000 BTU. It is also alpha good test to appreciate clinical improvement after Rituximab treatment.

Noninactivation of thyrotropin by cultured porcine thyroid cells.

Freshly isolated porcine thyroid cells were cultured in the presence of highly purified porcine thyrotropin. Cells associate into follicles between the second and tenth day of culture and later form a monolayer. The biological and immunological activity of thyrotropin was measured daily in the media. Thyrotropin concentration and biological activity remained unchanged from the onset of the culture up to day 14. Limiting factors influencing thyroglobulin biosynthesis do not appear before day 13. The loss of follicular organization at day 10 cannot be explained by thyrotropin degradation in the medium. Considering the number of receptors per cell and the half life of the thyrotropin . receptor complex in the two dissociation compartments previously demonstrated, it appears in terms of both biological activity and affinity for the receptors that the thyrotropin molecules released from the first compartment do not differ from native molecules. It can be calculated that at least 31% of the molecules released from the second compartment are not inactivated. Thus, it is probable that the catabolism of thyrotropin on the receptor, or near the receptor site, does not play an important role in the regulation of thyroid cell function in vitro.

Efficacy of chimeric molecules directed towards multiple somatostatin and dopamine receptors on inhibition of GH and prolactin secretion from GH-secreting pituitary adenomas classified as partially responsive to somatostatin analog therapy.

OBJECTIVE: This study compared the potency of a somatostatin receptor (sstr)2-sstr5 analog, BIM-23244, of an sstr2-dopamine D2 receptor (sstr2-DAD2) molecule, BIM-23A387 and of new somatostatin-dopamine chimeric molecules with differing, enhanced affinities for sstr2, sstr5 and DAD2, BIM-23A758, BIM-23A760 and BIM-23A761, to suppress GH and prolactin (PRL) from 18 human GH adenomas that are partially responsive to octreotide or lanreotide. MATERIALS AND METHODS: The sstr2, sstr5 and DAD2 mRNA levels were determined by RT-PCR. The effect of drugs was tested in cell cultures at various concentrations. RESULTS: In all tumors, the sstr2, sstr5 and DAD2 mRNA levels were coexpressed (mean levels+/-s.e.m. 0.4+/-0.1, 5.3+/-1.9 and 2.0+/-0.4 copy/copy beta-glucuronidase). In 13 tumors, the maximal suppression of GH secretion produced by BIM-23A387 (30+/-3%) and BIM-23244 (28+/-3%) was greater than that produced by octreotide (23+/-3%). In six out of 13 tumors, BIM-23A758, BIM-23A760 and BIM- 23A761 produced greater maximal suppression of GH secretion than octreotide (33+/-5, 38+/-2 and 41+/-2 vs 24+/-2%). Their EC(50) values were 10, 2 and 4 pmol/l. BIM-23A761 was more effective than BIM-23A387 in GH suppression (41+/-2 vs 32+/-4%). The new chimeric molecules produced maximal PRL suppression greater than octreotide (62+/-8 to 74+/-5 vs 46+/-11%). CONCLUSIONS: Novel dopamine-somatostatin chimeric molecules with differing, enhanced activity at sstr2, sstr5 and DAD2, consistently produced significatly greater suppression of GH and PRL than either octreotide or single-receptor-interacting ligands in tumors from patients classified as only partially responsive to octreotide therapy. The higher efficacy of the chimeric compounds was, at least partially, linked to their high affinity for sstr2 (IC50 1-10 pmol/l). The other mechanisms by which such molecules produce an enhanced inhibition of GH remain to be elucidated.

Consensus statement: medical management of acromegaly.

In November 2003, the Pituitary Society and the European Neuroendocrine Association sponsored a consensus workshop in Seville to address challenging issues in the medical management of acromegaly. Participants comprised 70 endocrinologists and neurosurgeons with international expertise in managing patients with acromegaly. All participants participated in the workshop proceedings, and the final document written by the scientific committee reflects the consensus opinion of the interactive deliberations. The meeting was supported by an unrestricted educational grant from Ipsen. No pharmaceutical representatives participated in the program planning or in the scientific deliberations.

Different pathways of secretion for glycosylated and nonglycosylated human prolactin.

Human prolactinoma cells in culture secrete the monomeric nonglycosylated form of human PRL (NG-hPRL) and its glycosylated variant (G-hPRL). We have performed pulse-chase experiments to investigate the individual patterns of release of these two molecular variants. The cells were pulse labeled for 10 min with [35S]methionine and then chased for increasing periods of time up to 24 h. The secretion of newly synthesized G- and NG-hPRL was followed by immunoprecipitation of the chase medium and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Both forms were rapidly released (10 min of chase), but presented with different rates of secretion. Half-maximal release of G-hPRL occurred with 60-min chase, while 110 min were necessary for NG-hPRL. More than 50% of initially labeled G-hPRL was released in the medium vs. only 20% for NG-hPRL. Incubation of the cells with 8-chloroadénosine-cAMP during a 2-h chase period resulted in a 3.6-fold increase in the release of newly synthesized NG-hPRL and had only a slight effect on newly synthesized G-hPRL release (1.7-fold increase). The intracellular transit of labeled G- and NG-hPRL was investigated in cells treated by the ionophore monensin. The secretions of both newly synthesized forms were inhibited to the same extent, probably via an arrest of the transit at the level of the median Golgi, as judged by the delay of acquisition to endoglycosidase-H resistance for G-hPRL in monensin-treated cells. In contrast, Western blot analysis of the same medium-showed that monensin abolished the secretion of G-hPRL and had little effect on NG-hPRL. Our results on the different rates of secretion of G- and NG-hPRL indicate a sorting of the two forms into different compartments in the secretory pathway, with G-hPRL being secreted at a higher rate than NG-hPRL, possibly via a different intracellular route. The differential effects of 8Cl-cAMP and monensin further suggest that G-hPRL may be constitutively secreted after synthesis, while NG-hPRL secretion may involve a storage step.

The electrical properties of isolated human prolactin-secreting adenoma cells and their modification by dopamine.

Human prolactinoma cells were maintained in culture for a period of at least 8 days and were able to secrete PRL in large amounts. This secretion was inhibited by bromocriptine, an agonist of dopaminergic receptors, in a dose-dependent manner. The cells showed electrical activity (action potentials) which was blocked by inhibitors of calcium current (cobalt, manganese), whereas it was insensitive to blockers of sodium current (tetrodotoxin). At the resting potential of the cell, dopamine induced a hyperpolarizing response such that action potentials no longer occurred. This effect was due to increase of the membrane conductance and depended on the cell potential. The reversal potential of this response was at -100 mV, which suggests the involvement of potassium ions. Bromocriptine and RU 24213, which are strong dopaminergic receptor agonists, both induced responses identical to the dopamine-induced response. The D2 receptor antagonists (haloperidol, domperidone, and spiperone) blocked the dopamine-induced response in a reversible manner. The D1 antagonist of dopaminergic receptors flupentixol had no effect on the dopamine response. It is concluded that the dopamine modulation of electrical activity involving calcium current may be an early important step in the mechanism by which dopamine inhibits PRL release.

Immunoreactive somatostatin in rat hypophysial portal blood.

Somatostatin levels have been determined by RIA in hypophysial portal blood of pentobarbital-anesthetized male rats. In most animals, immunoreactive somatostatin (SRIF) levels were higher in hypophysial portal blood than in systemic blood. In euthyroid rats, the mean level was 158 +/- 27 pg/ml (n = 8); SRIF was undetectable (less than 30 pg/ml) in systemic blood of these rats. It is suggested that endogenous SRIF was not degraded during the collection of stalk blood, since synthetic SRIF is stable when incubated in rat serum during 4 min at 37 c and 2 h at 0 C, i.e. under the conditions the blood was kept during the collection. SRIF in hypophysial portal plasma had the same immunoreactivity with a specific antiserum against SRIF as did synthetic SRIF. Gel filtration of hypophysial portal plasma revealed two immunoreactive peaks, the major one corresponding to synthetic SRIF, the smaller one representing a larger molecular form. Thyroidectomy and excess of T4 did not modify the levels of SRIF in hypophysial portal blood, suggestinc SRIF is stable when incubated in rat serum during 4 min at 37 C and 2 h at 0 C, i.e. under the conditions the blood was kept during the collection. SRIF in hypophysial portal plasma had the same immunoreactivity with a specific antiserum against SRIF as did synthetic SRIF. Gel filtration of hypophysial portal plasma revealed two immunoreactive peaks, the major one corresponding to synthetic SRIF, the smaller one representing a large molecular form. Thyroidectomy and excess of T4 did not modify the levels of SRIF in hypophysial portal blood, suggesting that the feedback of thyroid hormones on TSH secretion does not involve changes in the secretion of SRIF by the hypothalamus.

Polymorphism of prolactin secreted by human prolactinoma cells: immunological, receptor binding, and biological properties of the glycosylated and nonglycosylated forms.

Multiple forms of PRL differing in their physicochemical and biological characteristics have been described. We have analyzed the molecular forms of human (h) PRL released in culture by pure hPRL-secreting tumors with a particular attention to glycosylated hPRL. The prolactinoma cells from six different tumors released, in serum-free conditions, 10-28 mg hPRL. The combination of polyacrylamide gel electrophoresis and immunoblotting techniques using a [125I]anti-hPRL monoclonal antibody allowed qualitative and quantitative analysis of the hPRL variants. The ratio of the glycosylated 25,000-mol wt form (G-hPRL) to the 23,000-mol wt nonglycosylated monomeric hPRL (NG-hPRL) varied from 0.13 to 0.25. Under the conditions of our studies, cleaved forms of the hormone (19,000 and 15,000 mol wt) accounted for less than 5% of the total immunoreactivity. G- and NG-hPRL were subsequently purified by gel filtration and lectin affinity chromatography. G-hPRL appeared fully sensitive to endoglycosidase F digestion, further supporting the presence of a freely accessible N-linked carbohydrate chain. When assayed for their ability to react with polyclonal antibodies directed against hPRL in a competitive RIA, G-hPRL was 3 times less immunoreactive than NG-hPRL. However, both types of hPRL exhibited superimposable displacement curves when tested in an immunoassay using an anti-hPRL monoclonal antibody. In binding studies using crude rabbit mammary gland membranes G-hPRL was half as potent as NG-hPRL. In stimulating the growth of the Nb2 lymphoma cell line, G-hPRL was 50% less active than NG-hPRL. Thus 1) under basal conditions, hPRL undergoes partial and variable glycosylation; 2) glycosylation of the hormone may modulate its immunoreactivity; 3) glycosylation of hPRL not only lowers its mammary gland receptor binding capacity but also its growth-promoting activity.

Three year follow-up of acromegalic patients treated with intramuscular slow-release lanreotide.

Somatostatin analogs are an alternative treatment to pituitary surgery and radiotherapy in acromegalic patients. Recently, a depot long-lasting formulation of slow release (SR) lanreotide has been shown to be effective in the short-term control of GH hypersecretion in acromegalic patients. We report the long-term follow-up of a cohort of 22 acromegalic patients treated with SR lanreotide during 1-3 yr. Thirteen females and 9 males, age 51 +/- 3 yr, presented with macroadenomas (n = 12), microadenomas (n = 8), or empty sella (n = 2). Seven patients previously had undergone a partial surgical removal of their adenomas, and 21 of them had mean plasma GH levels less than 5 micrograms/L during a previous octreotide treatment. According to GH values recorded after 3 months of twice monthly 30 mg SR lanreotide im injection, SR lanreotide was administered every 14 days (n = 13) or every 10 days (n = 9). At the 6-month visit, mean GH values were 5 micrograms/L or less in 68% and 2.5 micrograms/L or less in 27% of patients, and these results remained unchanged during the 1-3 yr follow-up period. During SR lanreotide treatment, the mean insulin-like growth factor I (IGF-I) concentrations remained in the normal range in 63% of patients. No escape from the treatment occurred in any of the cases. A significant decrease of the pituitary tumor volume was observed in 3 (13%) patients. The main side effect consisted of minor digestive problems during 48 h after each injection and was reported by 13 patients. Biannual gallbladder echographies revealed the occurrence of gallstones in 4 (18%) patients. In conclusion, these data confirm the efficacy and the tolerance of the long-term SR lanreotide administration (30 mg im every 10-14 days) in the control of acromegaly.

Direct action of opiates on bromocriptine-inhibited prolactin release by human prolactinoma cells in primary culture.

The present study was undertaken in order to examine the existence of opioid binding sites on cell membranes of human PRL-secreting tumors. Determination of opioid binding sites using different opiate ligands revealed one class of high affinity (KD, 1.3 nM) binding sites. Pharmacological characterization revealed kappa-1 selectivity (high affinity ethylketocyclazocine (EKC) binding, insensitive to 5 microM (D-Ala2, D-Leu5]enkephalin). Subsequently EKC was added to hPRL-secreting tumor cells in primary culture, alone or in combination with the dopaminergic agonist bromocriptine, and PRL release was measured. Opiates had no direct effect on PRL release by prolactinoma cells. When cells were preincubated with bromocriptine [6.6 +/- 4.8 (SD) X 10(-11) M], EKC (10(-11) to 10(-9) M) antagonized, in a dose-dependent manner, the dopaminergic inhibition of PRL release. The opiate effect was reversed by the opiate antagonist diprenorphine (10(-7) M). Cross-competition studies indicated that this effect was not due to the interaction of opiates with the dopaminergic receptor. In conclusion, opioid binding sites are found on prolactinoma cells. The binding of kappa-1 type opioid ligands modulates the inhibitory effect of dopamine upon PRL release.

Pit-1 gene expression in the human pituitary and pituitary adenomas.

The cellular basis for pituitary neoplasia is poorly understood. The POU domain protein Pit-1 is a pituitary-specific transcription factor involved in the generation, differentiation, and proliferation of three pituitary cell types: lactotrophs, somatotrophs, and thyrotrophs. In this study, we analyzed the expression of Pit-1 gene in a series of 15 different human pituitary tumors and compared it with that observed in normal tissue. Pit-1 transcripts, identical in size (2.4 and 4.5 kilobases) and sequence to those observed in normal tissue were evidenced in PRL-, GH-, and TSH-secreting tumors. Pit-1 is overexpressed (2.5- to 5-fold) in the PRL- and GH-secreting tumors, but to an extent consistent with the predominant cellular type of these adenomas. An isoform of Pit-1, with an insertion of 26 amino acids in the trans-activation domain as a result of alternative splicing, is also present in both normal and tumoral tissues. It is concluded that human pituitary tumorigenesis does not seem to be associated with a gross alteration of Pit-1 gene expression.

Impact of gsp oncogene on the expression of genes coding for Gsalpha, Pit-1, Gi2alpha, and somatostatin receptor 2 in human somatotroph adenomas: involvement in octreotide sensitivity.

The impact of the gsp oncogene on the expression of genes engaged in the somatotroph cell phenotype remains poorly understood in human somatotroph adenomas. As the gsp oncogene is associated with an increased octreotide (somatostatin agonist) sensitivity, a group of 8 somatotroph adenomas bearing the gsp mutation (gsp+) and another group of 16 adenomas without the mutation (gsp-) were analyzed, all of them presenting variable octreotide sensitivities. The expressions of genes encoding for G(s)alpha, Pit-1, G(i2)alpha, and SSTR2, involved in the regulation of secretory activity in somatotroph cells, were assessed by Northern blot. A decreased expression of the G(s)alpha gene was found in gsp + tumors, suggesting the existence of a negative feedback of the oncogenic protein upon its own messenger ribonucleic acid (mRNA). In contrast, G(i2)alpha, Pit-1, and GH messengers were not significantly different in the groups. A positive correlation between the in vitro and in vivo GH octreotide-induced secretory inhibition and the expression of SSTR2 mRNA was found. However, the expression of the gene for SSTR2 appeared not to be different between gsp + and gsp-, even when the octreotide sensitivity was significantly higher in the adenomas carrying the mutation. Interestingly, the SSTR2 gene expression was significantly correlated to those of G(i2)alpha and Pit-1. In the same way, the G(s)alpha mRNA expression was positively correlated with those of Gi2alpha and Pit-1. Such correlations strongly suggest a concerted dysregulation of the expression of these genes in both categories of adenomas. The loss of the octreotide sensitivity represents one aspect of the dysregulation process that partially results from the decreased SSTR2 expression. However, the improvement of the sensitivity associated with the presence of the gsp oncogene seems to proceed in a way different from SSTR2 expression.