Long-Term Persistence of Inappropriate Antidiuretic Hormone Secretion Following Minor Head Injury.

Unlabelled: The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common cause of euvolemic hyponatremia, resulting from non-osmotic release of antidiuretic hormone (ADH). SIADH is frequently associated with neurological conditions, including traumatic brain injury (TBI). TBI-associated SIADH usually develops within days to weeks and resolves within a few weeks.

Spontaneous Periodic Hypothermia with Confirmed Epilepsy: A Report of Two Cases.

Unlabelled: Spontaneous periodic hypothermia (SPH) is an exceptionally rare condition characterised by paroxysmal episodes of spontaneous hypothermia. While commonly associated with Shapiro syndrome, which includes SPH, hyperhidrosis and agenesis of the corpus callosum, there are also cases of SPH that do not exhibit these defining characteristics, known as 'Shapiro syndrome variant'. These variants may present with diverse brain imaging findings but no agenesis of the corpus callosum, suggesting different potential aetiologies.

Treatment Guidelines for Hyponatremia: Stay the Course.

International guidelines designed to minimize the risk of complications that can occur when correcting severe hyponatremia have been widely accepted for a decade. On the basis of the results of a recent large retrospective study of patients hospitalized with hyponatremia, it has been suggested that hyponatremia guidelines have gone too far in limiting the rate of rise of the serum sodium concentration; the need for therapeutic caution and frequent monitoring of the serum sodium concentration has been questioned. These assertions are reminiscent of a controversy that began many years ago.

Intestinal Pseudo-Obstruction with Life-Threatening Hypokalaemia in a Patient with Adult-Onset Still's Disease.

Unlabelled: Adult-onset Still's disease (AOSD) is a rare autoinflammatory disorder that can lead to a cytokine storm, causing a range of symptoms. Acute intestinal pseudo-obstruction is another rare condition that results in intestinal obstruction without anatomical cause. Although the two conditions are rarely reported together, we present the case of a 62-year-old male who developed acute intestinal pseudo-obstruction in the context of an AOSD flare.

Not All MC States Are the Same: The Role of MC States in the Photochemical NN Ligand Release from [Ru(bpy)(NN)] Complexes.

Ruthenium(II) complexes feature prominently in the development of agents for photoactivated chemotherapy; however, the excited-state mechanisms by which photochemical ligand release operates remain unclear. We report here a systematic experimental and computational study of a series of complexes [Ru(bpy)(NN)] (bpy = 2,2'-bipyridyl; NN = bpy (), 6-methyl-2,2'-bipyridyl (), 6,6'-dimethyl-2,2'-bipyridyl (), 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole (), 1-benzyl-4-(6-methylpyrid-2-yl)-1,2,3-triazole (), 1,1'-dibenzyl-4,4'-bi-1,2,3-triazolyl ()), in which we probe the contribution to the promotion of photochemical NN ligand release of the introduction of sterically encumbering methyl substituents and the electronic effect of replacement of pyridine by 1,2,3-triazole donors in the NN ligand. Complexes to all release the ligand NN on irradiation in acetonitrile solution to yield [Ru(bpy)(NCMe)], with resultant photorelease quantum yields that at first seem counter-intuitive and span a broad range.

Theoretical Study of the Full Photosolvolysis Mechanism of [Ru(bpy)]: Providing a General Mechanistic Roadmap for the Photochemistry of [Ru(N^N)]-Type Complexes toward Both Cis and Trans Photoproducts.

A complete mechanistic picture for the photochemical release of bipyridine (bpy) from the archetypal complex [Ru(bpy)] is presented for the first time following the description of the ground and lowest triplet potential energy surfaces, as well as their key crossing points, involved in successive elementary steps along pathways toward - and -[Ru(bpy)(NCMe)]. This work accounts for two main pathways that are identified involving (a) two successive photochemical reactions for photodechelation, followed by the photorelease of a monodentate bpy ligand, and (b) a novel one-photon mechanism in which the initial photoexcitation is followed by dechelation, solvent coordination, and bpy release processes, all of which occur sequentially within the triplet excited-state manifold before the final relaxation to the singlet state and formation of the final photoproducts. For the reaction between photoexcited [Ru(bpy)] and acetonitrile, which is taken as a model reaction, pathways toward cis and trans photoproducts are uphill processes, in line with the comparative inertness of the complex in this solvent.

Synthesis of α-oxygenated β,γ-unsaturated ketones by a catalytic rearrangement strategy.

A straightforward two-step entry to α-oxgenated β,γ-unsaturated ketones from readily available α,β-unsaturated ketones is disclosed. It was found that bis(allylic) alcohols undergo a skeletal rearrangement in the presence of 1 mol% of cheap and non-corrosive p-toluenesulfonic acid. Computational studies were conducted to support the mechanism and to rationalise the influence of the catalyst acidity on the product selectivity.

Exploration of Uncharted PES Territory for [Ru(bpy)]: A New MC Minimum Prone to Ligand Loss Photochemistry.

We have identified a new MC state bearing two elongated Ru-N bonds to the same ligand in [Ru(bpy)]. This DFT-optimized structure is a local minimum on the PES. This distal MC state (MC) is destabilized by less than 2 kcal/mol with respect to the classical MC state (MC), and energy barriers to populate MC and MC from the MLCT state are similar according to nudged elastic band minimum energy path calculations.

Mild water restriction with or without urea for the longterm treatment of syndrome of inappropriate antidiuretic hormone secretion (SIADH): Can urine osmolality help the choice?

Background: Treatment options for chronic SIADH include water restriction (WR) and urea. The usefulness of urine osmolality to guide the choice of the treatment option is not clearly defined. We hypothesized that urine osmolality can indicate whether treatment with mild water restriction alone could be successful.

Hyponatraemia diagnosis and treatment clinical practice guidelines.

Hyponatremia, defined as a serum sodium concentration <135mmol/l, is the most common water-electrolyte imbalance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from mild to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay. Despite this, the management of hyponatremia patients remains problematic.

Methodological CASPT2 study of the valence excited states of an iron-porphyrin complex.

The singlet valence excited states of an iron-porphyrin-pyrazine-carbonyl complex are investigated up to the Soret band (about 3 eV) using multi-state complete active space with perturbation at the second order (MS-CASPT2). This complex is a model for the active site of carboxy-hemoglobin/myoglobin. The spectrum of the excited states is rather dense, comprising states of different nature: d→π* transitions, d→d states, π→π* excitations of the porphyrin, and doubly excited states involving simultaneous intra-porphyrin π→π* and d→d transitions.

Osmotic Stress-Induced Defective Glial Proteostasis Contributes to Brain Demyelination after Hyponatremia Treatment.

Adequate protein folding is necessary for normal cell function and a tightly regulated process that requires proper intracellular ionic strength. In many cell types, imbalance between protein synthesis and degradation can induce endoplasmic reticulum (ER) stress, which if sustained, can in turn lead to cell death. In nematodes, osmotic stress induces massive protein aggregation coupled with unfolded protein response and ER stress.

Urea minimizes brain complications following rapid correction of chronic hyponatremia compared with vasopressin antagonist or hypertonic saline.

Hyponatremia is a common electrolyte disorder that carries significant morbidity and mortality. However, severe chronic hyponatremia should not be corrected rapidly to avoid brain demyelination. Vasopressin receptor antagonists (vaptans) are now being widely used for the treatment of hyponatremia along with other alternatives like hypertonic saline.

Clinical practice guideline on diagnosis and treatment of hyponatraemia.

Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from subtle to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay in patients presenting with a range of conditions. Despite this, the management of patients remains problematic.

Clinical practice guideline on diagnosis and treatment of hyponatraemia.

Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from subtle to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay in patients presenting with a range of conditions. Despite this, the management of patients remains problematic.

Clinical practice guideline on diagnosis and treatment of hyponatraemia.

Hyponatraemia, defined as a serum sodium concentration <135 mmol/L, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. Hyponatraemia is present in 15-20% of emergency admissions to hospital and occurs in up to 20% of critically ill patients. Symptomatology may vary from subtle to severe or even life threatening.

Actual Therapeutic Indication of an Old Drug: Urea for Treatment of Severely Symptomatic and Mild Chronic Hyponatremia Related to SIADH.

Oral urea has been used in the past to treat various diseases like gastric ulcers, liver metastases, sickle cell disease, heart failure, brain oedema, glaucoma, Meniere disease, etc. We have demonstrated for years, the efficacy of urea to treat euvolemic (SIADH) or hypervolemic hyponatremia. We briefly describe the indications of urea use in symptomatic and paucisymptomatic hyponatremic patients.

Efficacy and tolerance of urea compared with vaptans for long-term treatment of patients with SIADH.

Background And Objectives: Vaptans (vasopressin V(2)-receptor antagonists) are a new approach for the treatment of hyponatremia. However, their indications remain to be determined, and their benefit compared with that of the usual treatments for the syndrome of inappropriate antidiuretic hormone secretion (SIADH) have not been evaluated. This prospective, long-term study compared the efficacy, tolerability, and safety of two oral vaptans with those of oral urea in patients with SIADH.

Astrocytes are an early target in osmotic demyelination syndrome.

Abrupt osmotic changes during rapid correction of chronic hyponatremia result in demyelinative brain lesions, but the sequence of events linking rapid osmotic changes to myelin loss is not yet understood. Here, in a rat model of osmotic demyelination syndrome, we found that massive astrocyte death occurred after rapid correction of hyponatremia, delineating the regions of future myelin loss. Astrocyte death caused a disruption of the astrocyte-oligodendrocyte network, rapidly upregulated inflammatory cytokines genes, and increased serum S100B, which predicted clinical manifestations and outcome of osmotic demyelination.

Minocycline protects against neurologic complications of rapid correction of hyponatremia.

Osmotic demyelination syndrome is a devastating neurologic condition that occurs after rapid correction of serum sodium in patients with hyponatremia. Pathologic features of this injury include a well-demarcated region of myelin loss, a breakdown of the blood-brain barrier, and infiltration of microglia. The semisynthetic tetracycline minocycline is protective in some animal models of central nervous system injury, including demyelination, suggesting that it may also protect against demyelination resulting from rapid correction of chronic hyponatremia.

Treatment of euvolemic hyponatremia in the intensive care unit by urea.

Introduction: Hyponatremia in the intensive care unit (ICU) is most commonly related to inappropriate secretion of antidiuretic hormone (SIADH). Fluid restriction is difficult to apply in these patients. We wanted to report the treatment of hyponatremia with urea in these patients.

Re-induction of hyponatremia after rapid overcorrection of hyponatremia reduces mortality in rats.

Osmotic demyelination syndrome is a devastating neurologic disorder often seen after the rapid correction of chronic hyponatremia. The permeability of the blood-brain barrier is increased in experimental osmotic demyelination, and some have suggested that corticosteroids protect against this disorder by keeping the permeability of the blood-brain barrier low. We previously reported that re-lowering of the serum sodium after rapid correction of chronic hyponatremia was beneficial if performed early in the course (12 to 24 h).