admission. This proportion could already be greater in some parts of the country and may increase if referrals of cases of self-poisoning increase faster than the facilities for their assessment and management. The provision of social work and psychiatric expertise in casualty departments may be one means of preventing unnecessary medical admissions without risk to the patients. Dr Blake's and Dr Bramble's figures do not demonstrate, however, that any advantage would attach to medical teams taking over assessment from psychiatrists except that, by implication, assessments would be completed sooner by staff working on the ward full time. What the figures actually suggest is that if assessment of overdoses were left to house doctors there would be an increase in admissions to psychiatric units (by 19°U), outpatients (by 5O°'), and referrals to social services (by 140o). So for house doctors to assess overdoses would provide no economy for the psychiatric or social services. The study does not tell us what the consequences would have been for the six patients who the psychiatrists would have admitted but to whom the house doctors would have offered outpatient appointments. E J SALTER

Vitamin D deficiency.

Missale, Cristina, S. Russel Nash, Susan W. Robinson, Mohamed Jaber, and Marc G. Caron. Dopamine Receptors: From Structure to Function. Physiol. Rev. 78: 189–225, 1998. — The diverse physiological actions of dopamine are mediated by at least five distinct G protein-coupled receptor subtypes. Two D1-like receptor subtypes (D1 and D5) couple to the G protein Gs and activate adenylyl cyclase. The other receptor subtypes belong to the D2-like subfamily (D2 , D3 , and D4) and are prototypic of G protein-coupled receptors that inhibit adenylyl cyclase and activate K+ channels. The genes for the D1 and D5 receptors are intronless, but pseudogenes of the D5 exist. The D2 and D3 receptors vary in certain tissues and species as a result of alternative splicing, and the human D4 receptor gene exhibits extensive polymorphic variation. In the central nervous system, dopamine receptors are widely expressed because they are involved in the control of locomotion, cognition, emotion, and affect as well as neuroendocrine s...

Dopamine Receptors: From Structure to Function

GTPases are conserved molecular switches, built according to a common structural design. Rapidly accruing knowledge of individual GTPases--crystal structures, biochemical properties, or results of molecular genetic experiments--support and generate hypotheses relating structure to function in other members of the diverse family of GTPases.

The GTPase superfamily: conserved structure and molecular mechanism

Analysis of 13,023 genes in 11 breast and 11 colorectal cancers revealed that individual tumors accumulate an average of ˜90 mutant genes but that only a subset of these contribute to the neoplastic process. Using stringent criteria to delineate this subset, we identified 189 genes (average of 11 per tumor) that were mutated at significant frequency. The vast majority of these genes were not known to be genetically altered in tumors and are predicted to affect a wide range of cellular functions, including transcription, adhesion, and invasion. These data define the genetic landscape of two human cancer types, provide new targets for diagnostic and therapeutic intervention and monitoring.

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Consensus coding sequences of human breast and colorectal cancers

Small synthetic molecules called growth hormone secretagogues (GHSs) stimulate the release of growth hormone (GH) from the pituitary. They act through the GHS-R, a G protein-coupled receptor whose ligand has only been discovered recently. Using a reverse pharmacology paradigm with a stable cell line expressing GHS-R, we purified an endogenous ligand for GHS-R from rat stomach and named it "ghrelin," after a word root ("ghre") in Proto-Indo-European languages meaning "grow." Ghrelin is a peptide hormone in which the third amino acid, usually a serine but in some species a threonine, is modified by a fatty acid; this modification is essential for ghrelin's activity. The discovery of ghrelin indicates that the release of GH from the pituitary might be regulated not only by hypothalamic GH-releasing hormone, but also by ghrelin derived from the stomach. In addition, ghrelin stimulates appetite by acting on the hypothalamic arcuate nucleus, a region known to control food intake. Ghrelin is orexigenic; it is secreted from the stomach and circulates in the bloodstream under fasting conditions, indicating that it transmits a hunger signal from the periphery to the central nervous system. Taking into account all these activities, ghrelin plays important roles for maintaining GH release and energy homeostasis in vertebrates.

https://www.physiology.org/doi/pdf/10.1152/physrev.00012.2004

Ghrelin: Structure and Function

Pituitary adenomas arise from the replication of a single mutated cell in which growth advantage may result from either activation of protooncogenes or inactivation of antioncogenes. The search for oncogenes in the genesis of these tumors has yielded negative results except for the gsp oncogene, that has been identified in about 30-40% of GH-secreting adenomas. gsp mutations cause constitutive activation of the Gs alpha subunit, leading to elevated cAMP formation and growth hormone hypersecretion. In the remaining tumor types several lines of evidence suggest that genes implicated in cell proliferation, such as early immediate genes, growth factors and growth factor receptors, are overexpressed. As far as the loss of antioncogenes in pituitary adenomas is concerned, no inactivating mutations of these genes have yet been identified in pituitary adenomas. However, despite the lack of mutations, several antioncogene proteins have been detected at extremely low levels in pituitary adenomas, consistent with a possible role of these tumor suppressors in pituitary tumor formation.

Genetic aspects of pituitary tumors.

Autoimmune hypophysitis (AH) is an inflammatory disease that can present either as empty sella or as pituitary mass. A 16-years-old girl was admitted at our Unit for primary amenorrhea. A pituitary MRI performed 2 years before for severe headache demonstrated a large sellar and suprasellar lesion. As a craniopharyngioma was suspected, the consultant neurosurgeon suggested the removal of the lesion. Two months later, a preoperative MRI showed the disappearance of the lesion and a residual empty sella, figure consistent with AH. When the patient came at our observation, basal and dynamic testing documented a state of hypopituitarism, high titers of antipituitary antibodies and a partial empty sella at MRI. Hormonal replacement therapy was started, obtaining a good clinical and biochemical control. Four years later, severe headache and a MRI suggestive of pituitary adenoma recurred. A relapse of the autoimmune phenomenon seemed the most feasible hypothesis. A MRI performed 3 months later did not show any pituitary lesion and empty sella was again described. This patient represents one of the few reported cases of recurrent hypophysitis and demonstrates that both pituitary enlargement and empty-sella can be seen in the same patient at different times of his history.

Anna Spada

Papers

Genetic aspects of pituitary tumors.

An unusual case of recurrent autoimmune hypophysitis.

New aspects in 'non-functioning' pituitary tumors

Somatic mutational analysis of DAX1 in testes from men with idiopathic azoospermia.

In memoriam. Giovanni Faglia (1930-2012).