Alterations in gene expression in MEN1-associated insulinoma development.

OBJECTIVES: To identify gene expression alterations associated with insulinoma formation and progression in 2 mouse models of multiple endocrine neoplasia type 1. METHODS: Mice were killed at 12 or 16 months, and pancreatic islets were isolated by enzymatic and physical disruption. Islets were separated by size representing control, normal, hyperplastic, and adenomous islets. RNA was isolated from these islets and profiled on Sentrix Mouse-6 Expression version 1 BeadChips. Array data were analyzed in GeneSpring. RESULTS: One hundred and one genes that were significantly (P ≤ 0.05) altered in hyperplastic islets and insulinomas compared with normal islets were identified. Of these, 64 gene elements showed reduced messenger RNA levels and 37 gene elements had increased gene expression compared with control islets. Altered expression of 3 genes, namely, Gata6, Tspan8, and s100a8, was confirmed by quantitative reverse transcription-polymerase chain reaction, and aberrant levels of Tspan8 and Lmo2 protein measured by Western blot correlated with the changes in messenger RNA levels. CONCLUSIONS: These results suggest that alterations in gene expression of Gata6, Tspan8, S100a8, and Lmo2 may act via novel pathways that play functionally important roles in Men1-associated tumor progression.

Decreased Glasgow Coma Scale score does not mandate endotracheal intubation in the emergency department.

BACKGROUND: Decreased consciousness is a common reason for presentation to the emergency department (ED) and admission to acute hospital beds. In trauma, a Glasgow Coma Scale score (GCS) of 8 or less indicates a need for endotracheal intubation. Some advocate a similar approach for other causes of decreased consciousness, however, the loss of airway reflexes and risk of aspiration cannot be reliably predicted using the GCS alone. STUDY OBJECTIVE: A survey of all poisoned patients with a decreased GCS who were admitted to an ED short-stay ward staffed by experienced emergency physicians, to establish the incidence of clinically significant aspiration or other morbidities and endotracheal intubation. METHODS: A prospective, observational study was conducted of all patients admitted to the ED short-stay ward with a decreased level of consciousness (GCS < 15). RESULTS: The study included 73 patients with decreased consciousness as a result of drug or alcohol intoxication. The GCS ranged from 3 to 14, and 12 patients had a GCS of 8 or less. No patient with a GCS of 8 or less aspirated or required intubation. There was one patient who required intubation; this patient had a GCS of 12 on admission to the ward. CONCLUSIONS: This study suggests that it can be safe to observe poisoned patients with decreased consciousness, even if they have a GCS of 8 or less, in the ED.

Global expression profiling of sex cord stromal tumors from Men1 heterozygous mice identifies altered TGF-beta signaling, decreased Gata6 and increased Csf1r expression.

Heterozygous disruption of the Men1 gene predisposes mice to the development of multiple endocrine tumors, accurately mimicking the human MEN1 cancer predisposition syndrome. Additionally, Men1(+/-) mice frequently develop sex cord adenomas. The mechanism underlying the susceptibility of these mice to sex cord tumor development has not been fully determined, but data suggest it may involve transcriptional regulation of key growth promoting/repressing genes. To identify potential menin-regulated genes that may be important for tumor suppression in sex cord cells, we compared the global gene expression profiles of testis and ovary adenomas with other endocrine tumors of the pancreas and pituitary from Men1 heterozygous mice and with control tissues. Gonadal tumors clustered separately from pancreas and pituitary tumors with only a few genes (e.g., Cdkn2c) commonly dysregulated in all tumor types. Testis and ovary tumors displayed a higher level of transcriptional similarity to each other than they did to their respective control tissues. Among genes that had decreased expression in tumors was significant over-representation of genes associated with the TGF-beta, hedgehog and Wnt signaling, indicating that loss of menin function affects these pathways at the level of transcription. Aberrant protein expression in Leydig and granulosa cells of 2 transcriptionally dysregulated gene products, Gata6 and Csf1r were confirmed by immunohistochemistry. We propose that sex cord tumor susceptibility in Men1(+/-) mice involves deregulated cell proliferation due to dysregulation of multiple cell growth regulating genes including: reduced Cdkn2c transcription, loss of TGF-beta pathway tumor suppressor function (e.g., Gata6) and transcriptional activation of Csf1r.

Severe hypoglycaemia in citalopram overdose.

We present two episodes of poisoning with citalopram in which the main feature was profound hypoglycaemia. Citalopram has been regarded as the most toxic of the selective serotonin reuptake inhibitors in overdose; however, hypoglycaemia is not one of the documented features of overdose. This is an important component of the toxicological profile of citalopram and a treatable cause of seizure activity that should be reported in poisoning information references.

Paediatric analgesia in the emergency department, are we getting it right?

OBJECTIVES: To measure the dose discrepancy in prescribing simple paediatric analgesia, in the emergency department, by comparing age and actual weight-based dosing. To establish the accuracy of the weight-estimation formula for children [weight kg=2 (age years+4)]. METHODS: A prospective survey conducted in the emergency departments of a UK teaching hospital and district general hospital. Two hundred and forty-seven children were prescribed simple analgesia in the form of paracetamol and ibuprofen or both. The dose prescribed was based on age. All children were weighed and a maximum dose based on the child's weight was calculated. The individual child's weight was also compared with the weight calculated using the estimation formula. RESULTS: A total of 247 patients were included. Two hundred and thirty-three patients were prescribed paracetamol. Fifteen patients were prescribed ibuprofen. The paracetamol group was administered a mean dose that was 67% (P<0.001) of the optimal dose that was based on weight. Ibuprofen dosage was 51% (P<0.001) of optimal dose. The weight-estimation formula underestimated weight by 16% (P<0.001). CONCLUSIONS: Prescribing analgesia by age often results in significant underdosing in the paediatric population. Predicting a child's weight using the calculation may result in underdosing.

Global expression profiling of murine MEN1-associated tumors reveals a regulatory role for menin in transcription, cell cycle and chromatin remodelling.

Although the identification of menin-interacting partners and other evidence support a role for menin, the multiple endocrine neoplasia type 1 gene (MEN1) product, in regulating gene expression, little is known about the cellular pathways dysregulated by menin loss during tumorigenesis. The mouse models of MEN1 accurately mimic the human syndrome and provide an opportunity to assess the transcriptional effects of Men1 deletion in different endocrine tumor types to identify common pathway aberrations underlying tumorigenesis in MEN1-affected tissues. We compared the global gene expression profiles of pituitary adenomas and pancreatic islet tumors with control tissues from wild-type littermates. Amongst the 551 differentially expressed genes was significant over-representation of genes associated with chromatin remodelling, transcription and cell cycling, including some genes known to encode menin-binding partners, e.g., Rhox5 and Mll1. Consistent with increased cell-cycle transition from G1 to S phase was an elevation of Cdc7 expression in the tumors, which was confirmed by qRT-PCR using independent samples. In support of previous findings in islet tumors, we found down-regulation of the cell-cycle regulator, p18, in both the pancreatic islet and pituitary adenomas, suggesting that reduced p18 levels may be important for Men1-related tumorigenesis in multiple tissues. Surprisingly, we identified increased p16 transcript in pancreatic islet and pituitary tumors. This was accompanied by increased cytoplasmic localization p16 protein in tumor cells. The specific genes and general pathways we have found to be commonly dysregulated in MEN1 tumors, provide a platform for determining their roles in endocrine tumorigenesis.

Ghrelin and a novel preproghrelin isoform are highly expressed in prostate cancer and ghrelin activates mitogen-activated protein kinase in prostate cancer.

PURPOSE: There is evidence that the hormone ghrelin stimulates proliferation in the PC3 prostate cancer cell line although the underlying mechanism(s) remain to be determined. A novel, exon 3-deleted preproghrelin isoform has previously been detected in breast and prostate cancer cells; however, its characterization, expression, and potential function in prostate cancer tissues are unknown. EXPERIMENTAL DESIGN: Expression of ghrelin and exon 3-deleted preproghrelin was investigated in prostate cancer cell lines and tissues by reverse transcription-PCR and immunohistochemistry. Proliferation and apoptosis assays were done in the LNCaP prostate cancer cell line to determine if ghrelin stimulates proliferation and/or cell survival. Stimulation of mitogen-activated protein kinase (MAPK) pathway activation by ghrelin was determined in PC3 and LNCaP cells by immunoblotting with antibodies specific for phosphorylated MAPKs. RESULTS: Prostate cancer tissues display greater immunoreactivity for ghrelin and exon 3-deleted preproghrelin than normal prostate tissues, and prostate cancer cell lines secrete mature ghrelin into conditioned medium. Treatment with ghrelin (10 nmol/L), but not the unique COOH-terminal peptide derived from exon 3-deleted preproghrelin, stimulates proliferation in the LNCaP cells (45.0 +/- 1.7% above control, P < 0.01) and rapidly activates the extracellular signal-regulated kinase-1/2 MAPK pathway in both PC3 and LNCaP cell lines. Ghrelin, however, does not protect prostate cancer cells from apoptosis induced by actinomycin D (1 microg/mL). The MAPK inhibitors PD98059 and U0126 blocked ghrelin-induced MAPK activation, as well as proliferation, in both cell lines. CONCLUSIONS: These data suggest that these components of the ghrelin axis may have potential as novel biomarkers and/or adjunctive therapeutic targets for prostate cancer.

Back pain in children: dig a bit deeper.

This report highlights the uncommon disease of Langerhans cell histiocytosis in the context of nontraumatic back pain. Langerhans cell histiocytosis has a broad range of presentations and should be borne in mind in many differential diagnoses in the emergency and general practice setting. Back pain in children, contrary to back pain in adults, is frequently the result of a treatable organic pathology and should be assessed thoroughly before a diagnosis of nonspecific or mechanical back pain is made.