A comparative study using thrombin generation and three different INR methods in patients on Vitamin K antagonist treatment.

INTRODUCTION: Vitamin K antagonist (VKA) treatment requires routine monitoring using the international normalized ratio (INR). However, different INR assays may vary in their results. The aim of this study was to assess the agreement of three different INR methods, compared with thrombin generation, in patients on VKA treatment. METHODS: Sixty patients attending the Anticoagulation Clinic at Mater Dei Hospital (Msida, Malta) for VKA monitoring between August and September 2015 were enrolled. The INR was tested using a point-of-care (POC) device (CoaguChek XS Plus, Roche Diagnostics) for both capillary and venous blood samples, a photo-optical (Sysmex CS-2100i/CA-1500, Siemens) and a mechanical clot detection system (Thrombolyzer XRC, Behnk Elektronik). All assays used human recombinant thromboplastin as reagent. Thrombin generation was performed using the calibrated automated thrombogram. RESULTS: There was a negative curvilinear correlation between the endogenous thrombin potential and different INR assays (r≤-.75) and a strong positive linear correlation between the CoaguChek XS Plus on capillary samples and the other INR methodologies (r≥.96). CONCLUSION: All different INR assays showed good correlation with the thrombin generation potential. The POC INR showed one of the highest correlation coefficients with thrombin generation, confirming the POC devices as an accurate, valid alternative to laboratory INR in VKA patients.

ISL1 Is Necessary for Maximal Thyrotrope Response to Hypothyroidism.

ISLET1 is a homeodomain transcription factor necessary for development of the pituitary, retina, motor neurons, heart, and pancreas. Isl1-deficient mice (Isl1(-/-)) die early during embryogenesis at embryonic day 10.5 due to heart defects, and at that time, they have an undersized pituitary primordium. ISL1 is expressed in differentiating pituitary cells in early embryogenesis. Here, we report the cell-specific expression of ISL1 and assessment of its role in gonadotropes and thyrotropes. Isl1 expression is elevated in pituitaries of Cga(-/-) mice, a model of hypothyroidism with thyrotrope hypertrophy and hyperplasia. Thyrotrope-specific disruption of Isl1 with Tshb-cre is permissive for normal serum TSH, but T4 levels are decreased, suggesting decreased thyrotrope function. Inducing hypothyroidism in normal mice causes a reduction in T4 levels and dramatically elevated TSH response, but mice with thyrotrope-specific disruption of Isl1 have a blunted TSH response. In contrast, deletion of Isl1 in gonadotropes with an Lhb-cre transgene has no obvious effect on gonadotrope function or fertility. These results show that ISL1 is necessary for maximal thyrotrope response to hypothyroidism, in addition to its role in development of Rathke's pouch.

PITX2 AND PITX1 regulate thyrotroph function and response to hypothyroidism.

Pitx2 is a homeodomain transcription factor required in a dose-dependent manner for the development of multiple organs. Pitx2-null homozygotes (Pitx2(-/-)) have severe pituitary hypoplasia, whereas mice with reduced-function alleles (Pitx2(neo/neo)) exhibit modest hypoplasia and reduction in the developing gonadotroph and Pou1f1 lineages. PITX2 is expressed broadly in Rathke's pouch and the fetal pituitary gland. It predominates in adult thyrotrophs and gonadotrophs, although it is not necessary for gonadotroph function. To test the role of PITX2 in thyrotroph function, we developed thyrotroph-specific cre transgenic mice, Tg(Tshb-cre) with a recombineered Tshb bacterial artificial chromosome that ablates floxed genes in differentiated pituitary thyrotrophs. We used the best Tg(Tshb-Cre) strain to generate thyrotroph-specific Pitx2-deficient offspring, Pitx2(flox/-;)Tg(Tshb-cre). Double immunohistochemistry confirmed Pitx2 deletion. Pitx2(flox/-);Tg(Tshb-cre) mice have a modest weight decrease. The thyroid glands are smaller, although circulating T(4) and TSH levels are in the normal range. The pituitary levels of Pitx1 transcripts are significantly increased, suggesting a compensatory mechanism. Hypothyroidism induced by low-iodine diet and oral propylthiouracil revealed a blunted TSH response in Pitx2(flox/-);Tg(Tshb-cre) mice. Pitx1 transcripts increased significantly in control mice with induced hypothyroidism, but they remained unchanged in Pitx2(flox/-);Tg(Tshb-cre) mice, possibly because Pitx1 levels were already maximally elevated in untreated mutants. These results suggest that PITX2 and PITX1 have overlapping roles in thyrotroph function and response to hypothyroidism. The novel cre transgene that we report will be useful for studying the function of other genes in thyrotrophs.

Expression of the hypothalamic transcription factor Nhlh2 is dependent on energy availability.

Mice with a deletion of the hypothalamic basic helix-loop-helix transcription factor Nhlh2 display adult onset obesity, implicating Nhlh2 in the neuronal circuits regulating energy availability. Nhlh2 colocalises with the hypothalamic thyrotrophin-releasing hormone (TRH) neurones in the paraventricular nucleus (PVN) and pro-opiomelanocortin (POMC) neurones in the arcuate nucleus. We show that Nhlh2 expression is significantly reduced in response to 24-h food deprivation in the arcuate nucleus, PVN, lateral hypothalamus, ventromedial hypothalamus (VMH) and dorsomedial hypothalamus (DMH). Food intake for 2 h following deprivation stimulates Nhlh2 expression in the arcuate nucleus and the PVN, and leptin injection following deprivation results in increased Nhlh2 expression in the arcuate nucleus, PVN, lateral hypothalamus, VMH, and DMH. Hypothalamic Nhlh2 expression in response to leptin injection is maximal by 2 h. Following leptin injection, Nhlh2 mRNA colocalises in POMC neurones in the arcuate nucleus and TRH neurones in the PVN. Nhlh2 mRNA expression in POMC neurones in the arcuate nucleus and TRH neurones in the PVN is reduced with energy deprivation and is stimulated with food intake and leptin injection. Modulation of POMC expression in response to changes in energy availability is not affected in mice with a targeted deletion of Nhlh2. However, deletion of Nhlh2 does result in loss of normal TRH mRNA expression in mice exposed to food deprivation and leptin stimulation. These data implicate Nhlh2 as a regulatory target of the leptin-mediated energy availability network of the hypothalamus, and TRH as a putative downstream target of Nhlh2.

Genetic analysis of NHLH2 and its putative role in bovine body weight control.

The control of energy balance is fundamental to adult animals and is necessary for weight gain/loss, reproductive capacity and general health. In mice, targeted deletion of the neuronal transcription factor Nhlh2 results in adult-onset obesity because of reduced exercise and infertility because of reduced sexual behaviour. Nhlh2 (NHLH2 for humans) is expressed in the hypothalamus, particularly in neurons that have been shown to regulate energy balance. We have cloned the bovine Nhlh2 gene (bNHLH2) and we have shown that bNHLH2 is also expressed in the hypothalamus. Phylogenetic analysis of Nhlh2 reveals that it is very highly conserved in humans, mice, chimps and cattle, and found in organisms with simpler nervous systems, including Caenorhabditis elegans and Drosophila. Using a cattle-human comparative map and online databases, we have evidence that bNHLH2 is located near a quantitative trait locus for marbling on bovine chromosome 3 between microsatellite markers BM723 and BMS963. Cloning of the bNHLH2 gene from Holstein cattle and a mixed breed individual and comparison with Hereford sequences shows that the gene is highly conserved among bovine breeds.

Use of albumin in intensive care units in the United kingdom.

OBJECTIVE: To review the use of intravenous albumin solutions in intensive care units in the United Kingdom. METHODS: A postal questionnaire was sent to the clinical directors of all intensive care units in the United Kingdom (n = 292) asking about their use and indications for intravenous albumin solutions. RESULTS: Responses were received from 261 (89.4%) intensive care units (ICUs). The units were classified as general ICUs (n = 198), paediatric ICUs (n = 22) and combined intensive care/coronary care units (ICU/CCUs) (n = 41). Of the 261 units that replied, 181 (69.3%) reported using intravenous albumin, although the indications varied between units particularly in paediatric intensive care units. The alternatives to albumin also varied between the units. The general ICUs favoured hydroxyethyl starch (n = 129, 65.2%) and/or gelatin solutions (n = 87, 43.9%), as did the combined ICU/CCUs (n = 28, 68.3% and/or n = 23, 56.1% respectively). However, of the paediatric ICUs that used an alternative to albumin solutions (n = 21/22), 12 favoured crystalloid solutions (54.5%) and 9 favoured gelatin solutions (40.9%). We also assessed the impact of the recent review by the Cochrane Injuries Group Reviewers on the use of albumin and found that the respondents of 131 units (50.2%) reported that this study influenced their use of intravenous albumin. Of the 80 units that did not use albumin solutions, 33 units reported that they had ceased using intravenous albumin following the review from the Cochrane Injuries Group Reviewers. CONCLUSIONS: Approximately two-thirds of intensive care units in the United kingdom reported using intravenous albumin, although the indications varied between units. In many of these units the use of intravenous albumin had been influenced by the recent review by the Cochrane Injuries Group Reviewers on the use of albumin.

Research priorities in critical care medicine in the UK.

OBJECTIVES: To establish priorities for research in critical care medicine in the UK using survey and nominal group (NG) techniques. DESIGN: The senior doctor and nurse from 325 intensive care units (ICUs) in the UK were invited to contribute up to ten research questions relevant to intensive care organisation, practice or outcomes. These were then ranked twice using a Likert scale by a panel (nominal group) consisting of ten doctors (two trainees) and two nurses from university teaching and district general (community) hospitals. The first ratings were performed privately, and the second after group discussion. Thirty questions, ten each with strong, moderate or weak support, were then returned for rating by the originating ICU staff and the results compared with those of the NG. RESULTS: One hundred eighty-five respondents (35.6 % university teaching, 62.1% district general, 2.3 % not stated) provided 811 questions of which 722 were research hypotheses. The most frequently identified topics were the evaluation of high dependency care, ICU characteristics, treatments for acute lung injury and acute renal failure, nurse:patient ratios, pulmonary artery catheterisation, aspects of medical and nursing practice, protocol evaluation, and interhospital transfers. These were condensed into 100 topics for consideration by the NG. Discussion and re-rating by the group resulted in strong support being offered for 37 topics, moderate support for 48, and weak support for 21. Following circulation of ten questions from each category, nine questions achieved strong support from both ICU staff and the NG. These were the effect on outcomes from critical illness of early intervention, high dependency care, nurse:patient ratios, interhospital transfers, early enteral feeding, optimisation of perioperative care, hospital type, regionalisation of paediatric intensive care and the use of pulmonary artery catheters. The absence of any questions relating to interventions targetting mediators of the immuno-inflammatory response could be a consequence of the failure of recent studies in sepsis to demonstrate benefits in outcome. CONCLUSIONS: The intensive care community in the UK appears to prioritise research into organisational aspects of clinical practice and practical aspects of organ-system support. Health services research and the biological sciences need to develop collaborative methods for evaluating interventions and outcomes.

Use of consensus development to establish national research priorities in critical care.

OBJECTIVES: To test the feasibility of using a nominal group technique to establish clinical and health services research priorities in critical care and to test the representativeness of the group's views. DESIGN: Generation of topics by means of a national survey; a nominal group technique to establish the level of consensus; a survey to test the representativeness of the results. SETTING: United Kingdom and Republic of Ireland. SUBJECTS: Nominal group composed of 10 doctors (8 consultants, 2 trainees) and 2 nurses. MAIN OUTCOME MEASURE: Level of support (median) and level of agreement (mean absolute deviation from the median) derived from a 9 point Likert scale. RESULTS: Of the 325 intensive care units approached, 187 (58%) responded, providing about 1000 suggestions for research. Of the 106 most frequently suggested topics considered by the nominal group, 37 attracted strong support, 48 moderate support and 21 weak support. There was more agreement after the group had met-overall mean of the mean absolute deviations from the median fell from 1.41 to 1.26. The group's views represented the views of the wider community of critical care staff (r=0.73, P<0.01). There was no significant difference in the views of staff from teaching or from non-teaching hospitals. Of the 37 topics that attracted the strongest support, 24 were concerned with organisational aspects of critical care and only 13 with technology assessment or clinical research. CONCLUSIONS: A nominal group technique is feasible and reliable for determining research priorities among clinicians. This approach is more democratic and transparent than the traditional methods used by research funding bodies. The results suggest that clinicians perceive research into the best ways of delivering and organising services as a high priority.