Medical Students' Exposure to Ethics Conflicts in Clinical Training: Implications for Timing UME Bioethics Education.

While there is significant consensus that undergraduate medical education (UME) should include bioethics training, there is widespread debate about how to teach bioethics to medical students. Educators disagree about course methods and approaches, the topics that should be covered, and the effectiveness and metrics for UME ethics training. One issue that has received scant attention is the timing of bioethics education during medical training. The existing literature suggests that most medical ethics education occurs in the pre-clinical years. Follow-up studies indicate that medical students in their clinical rotations have little recall or ability to apply ethics concepts that were learned in their pre-clinical training. Trainees also report a desire for medical ethics to be taught in the context of practical application, which would suggest that the timing of pre-clinical ethics education is flawed. However, moving bioethics training to the clinical years should not be assumed to be the solution to the problems of recall and theory application. We argue that the effectiveness of timing bioethics education will depend on when medical students witness or experience particular categories of ethical dilemmas during their training. Our overarching hypothesis is that ethics education will be most effective when the bioethics training on a particular topic correlates to experiential exposure to that ethical issue. The purpose of our current study was to describe medical students exposure to particular categories of ethical conflicts, dilemmas, or issues. Our results may help bioethics educators better strategize about the most effective timing of medical ethics training in UME.

European Renal Best Practice Guideline on kidney donor and recipient evaluation and perioperative care.

The European Best Practice Guideline group (EBPG) issued guidelines on the evaluation and selection of kidney donor and kidney transplant candidates, as well as post-transplant recipient care, in the year 2000 and 2002. The new European Renal Best Practice board decided in 2009 that these guidelines needed updating. In order to avoid duplication of efforts with kidney disease improving global outcomes, which published in 2009 clinical practice guidelines on the post-transplant care of kidney transplant recipients, we did not address these issues in the present guidelines.The guideline was developed following a rigorous methodological approach: (i) identification of clinical questions, (ii) prioritization of questions, (iii) systematic literature review and critical appraisal of available evidence and (iv) formulation of recommendations and grading according to Grades of Recommendation Assessment, Development, and Evaluation (GRADE). The strength of each recommendation is rated 1 or 2, with 1 being a 'We recommend' statement, and 2 being a 'We suggest' statement. In addition, each statement is assigned an overall grade for the quality of evidence: A (high), B (moderate), C (low) or D (very low). The guideline makes recommendations for the evaluation of the kidney transplant candidate as well as the potential deceased and living donor, the immunological work-up of kidney donors and recipients and perioperative recipient care.All together, the work group issued 112 statements. There were 51 (45%) recommendations graded '1', 18 (16%) were graded '2' and 43 (38%) statements were not graded. There were 0 (0%) recommendations graded '1A', 15 (13%) were '1B', 19 (17%) '1C' and 17 (15%) '1D'. None (0%) were graded '2A', 1 (0.9%) was '2B', 8 (7%) were '2C' and 9 (8%) '2D'. Limitations of the evidence, especially the lack of definitive clinical outcome trials, are discussed and suggestions are provided for future research.We present here the complete recommendations about the evaluation of the kidney transplant candidate as well as the potential deceased and living donor, the immunological work-up of kidney donors and recipients and the perioperative recipient care. We hope that this document will help caregivers to improve the quality of care they deliver to patients. The full version with methods, rationale and references is published in Nephrol Dial Transplant (2013) 28: i1-i71; doi: 10.1093/ndt/gft218 and can be downloaded freely from http://www.oxfordjournals.org/our_journals/ndt/era_edta.html.

Time to cardiac death after withdrawal of life-sustaining treatment in potential organ donors.

Organ donation after cardiac death (DCD) is increasing markedly, allowing more patients to benefit from transplantation. The time to cardiac death following withdrawal of life-supporting treatment varies widely and is an important determinant of whether organ donation occurs. A prospective multicenter study of potential DCD donors was undertaken to evaluate the time to death and identify associated factors. One hundred and ninety-one potential adult DCD donors at nine UK centers were studied. Treatment withdrawal comprised stopping ventilator support and inotropes. Demographics and physiological variables at the time of death were recorded. Following treatment withdrawal, all potential donors died, with median time to death of 36 min (range 5 min to 3.3 days). Eighty-three potential donors (43.5%) remained alive 1 h after treatment withdrawal, and 69 (36.1%) and 54 (28.3%) at 2 and 4 h, respectively. Univariate analysis revealed that age, cause of death, ventilation mode, inotrope use, systolic blood pressure, FiO2 and arterial pH at treatment withdrawal were all associated with time to death. Multivariable analysis showed that younger age, higher FiO2 and mode of ventilation were independently associated with shorter time to death. This information may aid planning and resourcing of DCD organ recovery and help maximize DCD donor numbers.

NPAS2: an analog of clock operative in the mammalian forebrain.

Neuronal PAS domain protein 2 (NPAS2) is a transcription factor expressed primarily in the mammalian forebrain. NPAS2 is highly related in primary amino acid sequence to Clock, a transcription factor expressed in the suprachiasmatic nucleus that heterodimerizes with BMAL1 and regulates circadian rhythm. To investigate the biological role of NPAS2, we prepared a neuroblastoma cell line capable of conditional induction of the NPAS2:BMAL1 heterodimer and identified putative target genes by representational difference analysis, DNA microarrays, and Northern blotting. Coinduction of NPAS2 and BMAL1 activated transcription of the endogenous Per1, Per2, and Cry1 genes, which encode negatively activating components of the circadian regulatory apparatus, and repressed transcription of the endogenous BMAL1 gene. Analysis of the frontal cortex of wild-type mice kept in a 24-hour light-dark cycle revealed that Per1, Per2, and Cry1 mRNA levels were elevated during darkness and reduced during light, whereas BMAL1 mRNA displayed the opposite pattern. In situ hybridization assays of mice kept in constant darkness revealed that Per2 mRNA abundance did not oscillate as a function of the circadian cycle in NPAS2-deficient mice. Thus, NPAS2 likely functions as part of a molecular clock operative in the mammalian forebrain.

Mosaicism in autosomal dominant polycystic kidney disease revealed by genetic testing to enable living related renal transplantation.

Patients with end-stage renal disease (ESRD) secondary to autosomal dominant polycystic kidney disease (ADPKD) receive fewer living-related kidney (LRK) transplants than other groups with ESRD. This relates to the difficulties in excluding the disease in potential donors. We report a case which highlights these difficulties and, by discovery of mosaicism for a new mutation, illustrates the role of clinical and molecular genetic resources in assessing young related kidney donors for patients with ADPKD.

Interpreting regulatory authority guidance on immunosuppressive therapy for renal transplantation: a response to the UK's National Institute for Clinical Excellence (NICE).

AIMS: A group of UK consultant transplant physicians and surgeons (the Consensus Group) met to consider the implications and interpretation of the National Institute for Clinical Excellence's (NICE) Technology Appraisal No. 85 on the use of immunosuppressive therapy for renal transplantation in adults. METHODS: This group considered what the implications of these guidelines might be for clinical practice and consensus was developed on those areas which were potentially open to different interpretations. A wider survey of nephrologists and transplant surgeons throughout the UK was also performed to gauge the impact of the NICE recommendations. RESULTS AND CONCLUSIONS: The outcome of the discussions of the Consensus Group are presented with particular reference to the recommendations of how to respond to calcineurin inhibitor (CNI) intolerance. The survey suggested that the publication of this NICE guidance has resulted in relatively few changes in prescribing practice: UK transplant centers continue to use a wide range of locally developed protocols for immunosuppressive therapy. These include the use of agents such as mycophenolate mofetil (MMF) and sirolimus, despite the fact that both drugs appeared to receive only conditional acceptance in the NICE Guidelines.

Moderate maternal nutrient restriction, but not glucocorticoid administration, leads to placental morphological changes in the baboon (Papio sp.).

The aims of the present study were to describe the ontogeny of spatial relationships between placental components in baboons and to investigate alterations in these indices following (1) moderate maternal nutrient restriction and (2) administration of glucocorticoids to pregnant baboons. We investigated the effects of glucocorticoids since they have been shown to play a role in the altered fetal growth that accompanies maternal nutrient restriction. Glucocorticoids are also given to pregnant women who threaten premature labor to accelerate fetal lung maturation. A third aim was to compare our findings to those in similar conditions in human pregnancy. Volumetric placental development in the baboon was similar to that in the human, although growth of fetal capillaries was slower over the second half of gestation in baboon than in human placentas. Intervillous space (IVS) and villous star volumes were halved at the end of gestation compared to the middle of gestation, as described in the human placenta. When mothers were fed 70% of feed eaten by controls fed ad libitum, placental volumetric structure was unchanged at mid-gestation but was altered by the end of gestation when placental weight, but not fetal weight or length, was decreased. At the end of gestation villous volume and surface area, capillary surface area, and the villous isomorphic coefficient were all decreased, In contrast, IVS hydraulic diameter was increased. All parameters were similar in pregnancies with male and female fetuses, with the exception of fetal capillary volume, which was unchanged in pooled samples and those from male fetuses, but decreased in pregnancies with female fetuses. Glucocorticoid administration during the second half of gestation did not produce any changes in the measured indices of placental composition. In summary, these changes in placental structure, associated with maternal nutrient restriction, would all act to decrease placental transport of nutrients. The influence of MNR on villous capillarization depends on fetal gender.

Functional dichotomy within the vomeronasal system: distinct zones of neuronal activity in the accessory olfactory bulb correlate with sex-specific behaviors.

Chemosensory neurons in the vomeronasal organ (VNO) detect pheromones that elicit social and reproductive behaviors in most terrestrial vertebrates. Vomeronasal receptor neurons are chemoarchitecturally divided into two populations based on their position in the VNO, the type of G-protein subunit expressed, the family of putative pheromone receptor expressed, and termination site of their axons in the accessory olfactory bulb (AOB). To investigate the functional implications of these two segregated VNO-AOB pathways, we stimulated mice with pheromonal cues associated with different behavioral contexts and examined cellular activation patterns in the AOB. Exposure of ICR male mice to BALB/c males resulted in aggressive behavior, accompanied by a VNO-dependent increase in c-fos immunoreactivity in a cluster of cells located almost exclusively in the caudal AOB in both strains. This caudal cluster of activated cells did not appear to require the overt display of aggressive behavior because it was present in both the dominant and submissive males and could be evoked when the stimulus animal was anesthetized. In contrast, exposure of an ICR male to an ICR female in diestrus resulted in activation of cells located predominantly in the rostral AOB. Our findings indicate that male-to-male interactions involving interstrain recognition activate a separate population of vomeronasal receptor neurons than chemosensory cues detected in a sexual context. The results suggest that the dichotomy in the peripheral vomeronasal system serves to separate pheromones based on the behaviors they drive. As such, the results provide a bioassay for identifying pheromone molecules.

Inhibition of lordosis behavior in the female rat by intraventricular infusion of prolactin and by chronic hyperprolactinemia.

The role of prolactin (PRL) in the control of the lordosis reflex of female rats was investigated. In the initial series of experiments, the normal high level of sexual receptivity observed in the ovariectomized, estrogen-progesterone (E-P) primed female rat was suppressed by intraventricular infusion of 100 ng PRL. Mating behavior remained suppressed 2, 3, and 5 hours following a single infusion of PRL into the third ventricle. In contrast, infusions of either an equal volume of the solvent vehicle (saline) or 100 ng of adrenocorticotropic hormone (ACTH) were ineffective in modulating the level of mating behavior in hormone-primed female rats. In a second series of experiments, chronic hyperprolactinemia was induced by pituitary transplants under the renal capsule in intact, normal cycle diestrus rats (N=12). A significant decrement in E-P induced mating behavior was observed at 12 and 14 weeks posttransplantation but not at 4 weeks. Sham-operated animals (N=12) displayed the characteristic pattern of behavior normally observed under exogenous E-P therapy. In summary, transient exposure as well as chronic exposure to high levels of PRL can suppress mating behavior, thus suggesting a possible role for PRL in the mediation of reproductive behavior in the female rat.

Coitus-induced release of luteinizing hormone in the proestrous rat: fantasy or fact?

The influences of mating on serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were evaluated in 4-day cyclic proestrous rats of the Wistar strain. Blood samples were collected via guillotine from mated and unmated controls at 1900-2000 h or 2100--2200 h. Serum LH levels were determined by two independent radioimmunoassays. There were no significant differences in LH measurement between assays. At 1900--2000 h, LH levels were high, but not significantly different, in both the mated and unmated control animals. By 2100-2200 h, serum LH concentration had dropped in unmated controls but was significantly elevated in mated animals. There was no significant elevation in FSH either 1900-2000 h or 2100--2200 h on the evening of proestrus. The data indicate that when LH levels are normally high, coitus cannot further potentiate LH release. However, when LH levels are declining, coitus is an effective and adequate stimulus to initiate elevations in serum LH.

Kinetics of the human leucocyte Na(+)-H+ antiport in essential hypertension.

Many membrane abnormalities have been described in human essential hypertension that may lead to an increased intracellular Na+ content, an example being reduced Na+ efflux by the sodium pump. We have previously found increased Na(+)-H+ antiport activity in leucocytes of hypertensive subjects. In the present study we examined the kinetics of this pump in 16 hypertensive and 20 carefully matched normotensive subjects by loading cells to different intracellular pH levels (as measured by fluorimetry) using a double-ionophore technique. The maximal rate of ethyl isopropyl amiloride-sensitive H+ efflux was significantly raised in leucocytes from the hypertensive subjects [75.3 +/- 6.2 versus 48.8 +/- 2.1 mmol/l per min in normotensives (mean +/- s.e.m.); P less than 0.001]. There was no difference in the affinity of the Na(+)-H+ antiport for intracellular H+. Intracellular buffering power at different internal pH levels in the range 6.0-7.1 did not differ in the two groups. We conclude that one reason for the reported intracellular alkalinity and increased sodium content of leucocytes from hypertensive subjects in bicarbonate-free media could be an increased number of active Na(+)-H+ exchangers or an increased turnover rate for each exchanger. A similar defect in vascular smooth muscle could account for the increased tone and thickening of the media. The abnormal maximal transport capacity of the leucocyte may be a useful membrane marker for future studies in human hypertension.

Leucocyte intracellular pH and Na+/H+ antiport activity in human hypertension.

Hypertension is associated with thickening of the wall of resistance vessels, but the cellular or genetic basis of this is unclear. Cell proliferation and intracellular alkalinization via increased Na+/H+ exchange are linked in the response of tissues to growth factors. To define a possible cellular basis for vascular medial thickening in hypertension, we studied leucocyte intracellular pH, buffering power and Na+/H+ antiport activity in 17 hypertensive and 17 age-, sex- and weight-matched normotensive subjects. The cells from hypertensive subjects were significantly more alkaline [median (range): 7.49 (7.26-7.95) versus 7.39 (7.25-7.53); P less than 0.01], and had a lower buffering power [8.95 (3.05-17.98) versus 12.57 (7.44-19.95) mmol/l per pH unit; P less than 0.02] than those from normotensive subjects. Moreover, the activity of the Na+/H+ antiport was higher when cells were acid-loaded to an intracellular pH of 6.7. The presence of a similar increased activity in vascular smooth muscle cells may be associated with increased cellular proliferation resulting in a thickened media or increased vascular smooth muscle contractility.

Prediction of patient responses to antihypertensive drugs using genetic polymorphisms: investigation of renin-angiotensin system genes.

OBJECTIVE: To investigate whether the M235T polymorphism of the angiotensinogen (AGT) gene and the insertion/deletion (I/D) polymorphism of the angiotensin-1 converting enzyme (ACE) gene predict blood pressure response to different antihypertensive agents. DESIGN: Sixty-three patients with untreated essential hypertension were randomly assigned in a placebo-controlled crossover comparison to atenolol 50 mg once daily, lisinopril 10 mg once daily and nifedipine SR 20 mg twice daily, and the effect on blood pressure was assessed by ambulatory blood pressure monitoring (ABPM). In a further 44 patients, placebo-controlled ABPM data were available after treatment with a single agent (atenolol 50 mg once daily in 16 cases and lisinopril 10mg once daily in 28 cases). The change in systolic and diastolic blood pressure achieved by each agent was analysed for association with genotypes at the AGT and ACE gene loci. METHODS: Polymerase chain reaction (PCR) amplification of genomic DNA from each individual was used to identify the I/D polymorphism of the ACE gene. The M235T polymorphism of the AGT gene was detected by Tth111I digestion of PCR product. RESULTS: There was no significant association between response to any drug and either the AGT M235T or ACE I/D polymorphisms. CONCLUSIONS: The large variability between individuals in the observed blood pressure response to these agents cannot be attributed to the polymorphisms analysed at the ACE and AGT loci.

Activation of an anatomically distinct subpopulation of accessory olfactory bulb neurons by chemosensory stimulation.

Chemosensory cues known as pheromones play a key role in rodent reproductive physiology and social interactions. Pheromone molecules are detected by receptor cells located in the vomeronasal organ and conveyed exclusively to the accessory olfactory bulb, and then to limbic and hypothalamic sites for integration with other factors modulating reproductive physiology. We report here that chemosensory cues from the female mouse selectively activate a subpopulation of cells located in the anterior part of the accessory olfactory bulb of the male mouse. Exposure of male mice to female-soiled bedding resulted in a massive induction of c-fos expression, which was primarily confined to neurons located in the anterior part of the accessory olfactory bulb and was eliminated by removal of the vomeronasal organ. Exposure of the male to soiled bedding from a different stain of male mice also elevated c-fos expression, but immunoreactive cells were more evenly distributed along the anterior-posterior axis of the accessory olfactory bulb. No treatment effects were observed in the main olfactory bulb. Previous studies have indicated that vomeronasal receptor neurons are divided into two populations based on location within the organ, site of termination in the accessory olfactory bulb, second messenger content and putative pheromone receptor expression. The present study suggests that the two populations of vomeronasal receptor neurons detect different chemosensory stimuli. Since male mouse- and female mouse-specific urinary substances modulate different aspects of male mouse behavior, the present results suggest that anatomically segregated populations of vomeronasal organ receptor cells modulate distinct behavioral patterns.

Signal processing in the vomeronasal system: modulation of sexual behavior in the female rat.

Chemosensory cues detected by the vomeronasal (VN) organ modulate a variety of social interactions in many species. In particular, activation of the VN system by pheromones regulates sexual behavior in the rodent. Although the exact nature of stimulus access to the organ is not clearly defined, the neuroanatomical pathway connecting the VN organ to hypothalamic centers controlling reproductive function is well established and relatively straightforward. Electrophysiological techniques have provided insight into the signal transduction process throughout the VN system. Combining behavioral studies with immunocytochemical detection of immediate early genes and neuropeptides reveals that gonadotropin hormone releasing hormone (GnRH)-containing neurons are specifically activated by stimulation of the VN organ. Furthermore, some of the activated GnRH neurons project to the ventromedial hypothalamus where they are hypothesized to induce sexual responsiveness. Early anecdotal evidence of an influence of the VN organ on human reproductive events has been substantiated by more recent anatomical, behavioral, and electrophysiological studies. Thus, further deciphering of the signal transduction process within the VN system of the rodent may yield unique insights into behaviors associated with human reproduction.

Leukocyte isotopically exchangeable intracellular sodium fractions in lean and overweight hypertensives.

Leukocyte intracellular sodium, as measured by flame photometry, is increased in essential hypertension, especially when associated with a body mass index greater than 27 kg.m-2. A triple isotope method for measuring the isotopically exchangeable pool of intracellular sodium was used to assess if this pool was increased in hypertension. No significant differences in the isotopically exchangeable intracellular sodium concentration were found between lean and overweight hypertensives compared with normotensive controls. Lean hypertensives with systolic blood pressures below the median had significantly lower exchangeable intracellular sodium concentrations than lean normotensives, whereas those with systolic blood pressures above the median had raised exchangeable intracellular sodium concentrations. The obese hypertensives did not show this trend. The exchangeable intracellular sodium concentration was correlated to systolic (r = .53, P less than .001) and diastolic (r = 0.39, P less than .01) blood pressure in hypertensives. We conclude that the increase in total cellular sodium content (as measured by flame photometry) in hypertensives described in previous studies is not associated with any increase in the isotopically exchangeable pool of intracellular Na+, except in those lean hypertensives with systolic blood pressures above the median. By implication, there may be an increased slowly exchangeable pool of intracellular Na+ in leukocytes from most hypertensives.

Solitary hypothalamic neurons inherently express vasopressin and tyrosine hydroxylase.

Hypothalamic neurons were grown as single cells in three-dimensional culture. Solitary neurons lacking cell contacts were immunocytochemically examined for inherent expression of vasopressin (VP), tyrosine hydroxylase (TH), and luteinizing hormone releasing hormone (LHRH). Immunoreactive VP and TH were detected within a day. Sixty to eighty-five percent of neurons displayed homogeneously distributed reaction product for VP or TH. One percent exhibited intense punctate staining of somas and varicosities. Few neurons stained for LHRH. Results indicate that hypothalamic neurons can express appropriate neuropeptides and transmitter-specific products without contacting other neurons or nonneuronal cells. Thus, this culture system may provide a useful model to study intrinsic neuronal processes.

Iontophoretic mapping of corticotropin-releasing factor (CRF) sensitive neurons in the rat forebrain.

Iontophoretic application of corticotropin-releasing factor (CRF) onto the membrane of individual brain neurons produced changes in the spontaneous occurrence of their extracellular action potentials. Neurons in the cortex and hypothalamus tended to be excited by the application of this 41-residue peptide, while those in the thalamus and lateral septal area were inhibited. In general, neurons excited by CRF were also inhibited by the local application of dopamine (DA) and morphine (MOR), while those which were inhibited by CRF were excited by DA and MOR. Glutamate excited the majority of cells tested independent of the other peptide responses. The results suggest that CRF activates several CNS regions with some specificity, and may be involved in neuronal modulation of pituitary as well as extrapituitary events.

The effect of LHRH antagonist analogs and an antibody to LHRH on mating behavior in female rats.

The action of two antagonist analogs and an antibody to luteinizing hormone-releasing hormone (LHRH) on sexual receptivity was studied in avariectomized, estrogen-progesterone primed female rats. Small amounts of each LHRH substance or saline was infused through a cannula positioned in either the third ventricle or arcuate-ventromedial (ARC-VMH) area of the hypothalamus. Infusions were carried out at the time of progesterone priming, which was 42 hrs post-estrogen treatment, and sexual receptivity, as denoted by the lordosis-to-mount ratio, was measured six hrs later. One antagonist analog, [D-pGlu1, D-Phe2, D-Trp3,6]-LHRH[1], had little or no effect on sexual receptivity when tested in either site. Similarly, an antibody to LHRH, tested only in the ARC-VMH, had no observable effect on lordotic behavior. However, the second and the most potent antagonist analog, [Ac-dehydro-Pro1, pCl-D-Phe2, D-Trp3,6]-LHRH[2], produced a marked and significant decrement in lordotic behavior when infused into either the third ventricle or ARC-VMH. These results suggest that this potent and long-acting, competitive antagonist analog of LHRH prevented endogenous LHRH from exerting its normal role in the induction of sexual receptivity and provide evidence to support the contention that the role of LHRH in mediating receptivity in the female rat is physiologically relevant.

Electrophysiological evidence for glutamate as a vomeronasal receptor cell neurotransmitter.

Bipolar receptor cells in the vomeronasal organ send axonal projections to the accessory olfactory bulb where they synapse with mitral cell dendrites. Although the nature of the synapse is thought to be excitatory, the neurotransmitter(s) involved has not yet been identified. Electrophysiological recordings of single neurons in the mitral cell layer of the AOB in response to vomeronasal nerve stimulation were conducted to characterize the synaptic response and the underlying neurotransmitter substance. Extracellular activity was recorded in vivo (whole animal) and in vitro (AOB slice) from female rats. In vivo, the predominant response to stimulation of the VNO was excitation. In many instances in the whole animal preparation, the excitation was followed by an inhibitory response. Attempts to block the excitatory response by ejecting kynurenic acid in close proximity to the mitral cell being recorded were not successful. Since this failure may have been due to inability of the antagonist to reach its presumed site of action at the dendrite, further recordings were carried out in vitro. In the AOB slice preparation, the predominant response to stimulation of the VN nerve endings was excitation. Superfusion of the non-NMDA antagonist, CNQX, into the medium resulted in a reduction of the orthodromic excitation in 5 of 8 cells. The NMDA antagonist, AP-5, was found to blunt orthodromic excitation in 1 of 4 cells. These results suggest that the excitatory response evoked in mitral cells followng stimulation of the VN nerve is mediated by glutamate.