"It Runs in Your Blood": Reflections from Treatment Seeking Gamblers on Their Family History of Gambling

There are considerable gaps in our understanding of the familial transmission of gambling problems. This convergent mixed-methods study aimed to explore the: (1) sources of heterogeneity in the familial (paternal, maternal, and sibling) transmission of gambling problems; (2) degree to which family-of-origin characteristics are associated with family-of-origin problem gambling; and (3) beliefs of gamblers about the nature of the familial transmission of problem gambling. The sample consisted of 97 treatment-seeking gamblers in Australia. One-quarter (25.5%) of participants reported that at least one family member (16.5% father, 7.5% mother, 7.6% siblings) living with them when they were growing up had a gambling problem. Most participants reported that family members with a positive history of problem gambling were biological relatives, lived with them full-time, and experienced long-term difficulties with gambling. Participants with a family history of problem gambling were young (less than 12 years of age) at the onset of parental, but not sibling, problem gambling, were women, and reported difficulties with the same gambling activity as their family member. Participants raised in families with problem gambling were more likely to report parental separation (risk ratio [RR] = 2.32) and divorce (RR = 2.83), and extreme family financial hardship (RR = 1.80), as well as low levels of paternal authoritative parenting than participants raised in non-problem gambling families. Qualitatively, both social learning and genetics were perceived to play a central role in the familial transmission of gambling problems. These findings inform theories of the familial transmission of gambling problems and the design of targeted prevention and intervention strategies.

Characterizing Agreement in the Level of Interarm Blood Pressure Readings of Adults in the Emergency Department (CALIBRATE Study)

Background: Increased interarm systolic blood pressure difference (IASBPD) is one of the major predictors of cardiovascular disease. An IASBPD of >10 mmHg is of clinical significance. However, studies have reported a high number of patients visiting the emergency department (ED) with high IASBPD and varying correlation of IASBPD to age, ethnic background, and comorbidities such as hypertension and diabetes. Objective: The CALIBRATE study aimed to measure the IABPDs in the multiethnic patient population presenting to the ED in Qatar and to assess the distribution of IASBPD in this population. Methods: In a sitting position, two consecutive blood pressure (BP) measurements were recorded from the right and left arms for each participant using a calibrated automated machine and appropriate cuff sizes. The data were recorded using predefined data fields, including patient demographics, past medical, and social and family history. The continuous variables were reported as mean or median based on the distribution of data. The data were analyzed using Stata MP 14.0. Results: A total of 1800 patients, with a mean age of 34 (10) years, were prospectively recruited from the ED. The median absolute systolic BP difference (ΔSBP) between the right and left arms was 6 (3-10) mmHg, and it was the same for the first (ΔSBP1) and the second readings (ΔSBP2). The absolute average of ΔSBP1 and ΔSBP2 was 7 (4-10) mmHg. The difference in systolic BP difference (SBP) of < 20 mmHg for interarm blood pressure was seen in the 95th percentile of the population. No meaningful association could be detected between the IABPD and the study variables such as age, demographics, regions of interest, and risk factors. Conclusion: In population presenting to the ED, the IASBPD of at least 20 mmHg reached at the 95th percentile, validating the known significant difference. The utility of SBP difference can be improved further by taking the average of two individual readings.

Noradrenergic depletion causes sex specific alterations in the endocannabinoid system in the Murine prefrontal cortex

Brain endocannabinoids (eCB), acting primarily via the cannabinoid type 1 receptor (CB1r), are involved in the regulation of many physiological processes, including behavioral responses to stress. A significant neural target of eCB action is the stress-responsive norepinephrine (NE) system, whose dysregulation is implicated in myriad psychiatric and neurodegenerative disorders. Using Western blot analysis, the protein expression levels of a key enzyme in the biosynthesis of the eCB 2-arachidonoylglycerol (2-AG), diacylglycerol lipase-α (DGL-α), and two eCB degrading enzymes monoacylglycerol lipase (MGL) and fatty acid amide hydrolase (FAAH) were examined in a mouse model that lacks the NE-synthesizing enzyme, dopamine β-hydroxylase (DβH-knockout, KO) and in rats treated with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4). In the prefrontal cortex (PFC), DGL-α protein expression was significantly increased in male and female DβH-KO mice (P < 0.05) compared to wild-type (WT) mice. DβH-KO male mice showed significant decreases in FAAH protein expression compared to WT male mice. Consistent with the DβH-KO results, DGL-α protein expression was significantly increased in male DSP-4-treated rats (P < 0.05) when compared to saline-treated controls. MGL and FAAH protein expression levels were significantly increased in male DSP-4 treated rats compared to male saline controls. Finally, we investigated the anatomical distribution of MGL and FAAH in the NE containing axon terminals of the PFC using immunoelectron microscopy. MGL was predominantly within presynaptic terminals while FAAH was localized to postsynaptic sites. These results suggest that the eCB system may be more responsive in males than females under conditions of NE perturbation, thus having potential implications for sex-specific treatment strategies of stress-related psychiatric disorders.

Predictors of outcomes of psychological treatments for disordered gambling: A systematic review

This systematic review aimed to synthesise the evidence relating to pre-treatment predictors of gambling outcomes following psychological treatment for disordered gambling across multiple time-points (i.e., post-treatment, short-term, medium-term, and long-term). A systematic search from 1990 to 2016 identified 50 articles, from which 11 socio-demographic, 16 gambling-related, 21 psychological/psychosocial, 12 treatment, and no therapist-related variables, were identified. Male gender and low depression levels were the most consistent predictors of successful treatment outcomes across multiple time-points. Likely predictors of successful treatment outcomes also included older age, lower gambling symptom severity, lower levels of gambling behaviours and alcohol use, and higher treatment session attendance. Significant associations, at a minimum of one time-point, were identified between successful treatment outcomes and being employed, ethnicity, no gambling debt, personality traits and being in the action stage of change. Mixed results were identified for treatment goal, while education, income, preferred gambling activity, problem gambling duration, anxiety, any psychiatric comorbidity, psychological distress, substance use, prior gambling treatment and medication use were not significantly associated with treatment outcomes at any time-point. Further research involving consistent treatment outcome frameworks, examination of treatment and therapist predictor variables, and evaluation of predictors across long-term follow-ups is warranted to advance this developing field of research.

Cryptic species diversity reveals biogeographic support for the 'mountain passes are higher in the tropics' hypothesis

The 'mountain passes are higher in the tropics' (MPHT) hypothesis posits that reduced climate variability at low latitudes should select for narrower thermal tolerances, lower dispersal and smaller elevational ranges compared with higher latitudes. These latitudinal differences could increase species richness at low latitudes, but that increase may be largely cryptic, because physiological and dispersal traits isolating populations might not correspond to morphological differences. Yet previous tests of the MPHT hypothesis have not addressed cryptic diversity. We use integrative taxonomy, combining morphology (6136 specimens) and DNA barcoding (1832 specimens) to compare the species richness, cryptic diversity and elevational ranges of mayflies (Ephemeroptera) in the Rocky Mountains (Colorado; approx. 40°N) and the Andes (Ecuador; approx. 0°). We find higher species richness and smaller elevational ranges in Ecuador than Colorado, but only after quantifying and accounting for cryptic diversity. The opposite pattern is found when comparing diversity based on morphology alone, underscoring the importance of uncovering cryptic species to understand global biodiversity patterns.

Changing paradigm of cryptococcal meningitis: an eight-year experience from a tertiary hospital in South India

BACKGROUND

Cryptococcal meningitis (CM) is a common opportunistic fungal infection causing sub-acute meningitis with the potential for complications and significant mortality. We conducted this study to describe the difference in presentation and outcome between HIV-infected and HIV-uninfected patients.

MATERIALS AND METHODS

Patients admitted to a tertiary care centre between 2005 and 2013 with confirmed CM were included in the analysis. Details of the clinical presentation, laboratory findings, treatment details, risk factors for infection and outcome were documented and analysed.

RESULTS

During the study period, 102 (87.2%) cases of CM occurred among HIV infected individuals, whereas 15 (12.8%) occurred among HIV-uninfected patients. HIV-infected patients with CM were younger compared with HIV-uninfected patients (38.2 ± 8.5 years vs. 45 ± 11.5 years; P = 0.07). The median duration of symptoms prior to presentation was shorter in the HIV-infected group (20 ± 32 vs. 30 ± 42; P = 0.03). There was no difference between the cerebrospinal fluid (CSF) lymphocyte counts, CSF protein counts, and CSF sugar levels in both the groups. The diagnostic yield of Cryptococcus was similar with CSF India ink smear (89% vs. 87%), CSF fungal culture (95% vs. 87%), and blood culture (100% vs. 75%) in both the groups. Case fatality rate in the HIV-infected group was 30.6%, whereas there were no deaths in the HIV-uninfected group.

CONCLUSION

HIV-infected patients with CM have a worse outcome compared to HIV-uninfected patients. The overall trend over 3 decades shows increasingly successful rates of treatment and hence early diagnosis and treatment are of paramount importance.

Radical cystectomy: Analysis of trends in UK practice 2004–2012, from the British Association of Urological Surgeons’ (BAUS) Section of Oncology Dataset

Objective:

To analyse the British Association of Urological Surgeons’ (BAUS) radical cystectomy (RC) dataset, to examine the trends in patient selection, use of neoadjuvant chemotherapy (NAC) and operative technique.

Methods:

Data for RC were entered into a database voluntarily, by operating surgeons. A comparison was made to the Hospital Episode Statistics (HES) data, to estimate the proportion of cases captured by the dataset.

Results:

From 2004 to 2012, data was collected on 5321 patients undergoing RC. This constituted 37.1% of all HES RC cases during the corresponding time period. Notable trends were: An increasing use of NAC, the introduction of minimally-invasive surgery (23.5% in 2012), a dramatic reduction in blood transfusion rates and the increasing yields from lymph node dissection. The ileal conduit urinary diversion predominated as the urinary diversion of choice (80% of cases).

Conclusions:

This analysis of a large multi-centre dataset provides insight into RC practice in the UK, over 8 years. The major weaknesses of the study were that only one-third of cases were recorded and that outcome data was very limited. Mandatory publication of outcome data from 2016 should increase the recording of cases and provide material for a more complete analysis.

Problem gambling and family violence: prevalence and patterns in treatment-seekers

The primary aim of this study was to explore the prevalence and patterns of family violence in treatment-seeking problem gamblers. Secondary aims were to identify the prevalence of problem gambling in a family violence victimisation treatment sample and to explore the relationship between problem gambling and family violence in other treatment-seeking samples. Clients from 15 Australian treatment services were systematically screened for problem gambling using the Brief Bio-Social Gambling Screen and for family violence using single victimisation and perpetration items adapted from the Hurt-Insulted-Threatened-Screamed (HITS): gambling services (n=463), family violence services (n=95), alcohol and drug services (n=47), mental health services (n=51), and financial counselling services (n=48). The prevalence of family violence in the gambling sample was 33.9% (11.0% victimisation only, 6.9% perpetration only, and 16.0% both victimisation and perpetration). Female gamblers were significantly more likely to report victimisation only (16.5% cf. 7.8%) and both victimisation and perpetration (21.2% cf. 13.0%) than male gamblers. There were no other demographic differences in family violence prevalence estimates. Gamblers most commonly endorsed their parents as both the perpetrators and victims of family violence, followed by current and former partners. The prevalence of problem gambling in the family violence sample was 2.2%. The alcohol and drug (84.0%) and mental health (61.6%) samples reported significantly higher rates of any family violence than the gambling sample, while the financial counselling sample (10.6%) reported significantly higher rates of problem gambling than the family violence sample. The findings of this study support substantial comorbidity between problem gambling and family violence, although this may be accounted for by a high comorbidity with alcohol and drug use problems and other psychiatric disorders. They highlight the need for routine screening, assessment and management of problem gambling and family violence in a range of services.

Frondoside A enhances the antiproliferative effects of gemcitabine in pancreatic cancer

Pancreatic cancer has a very poor prognosis. While gemcitabine is the mainstay of therapy and improves quality of life, it has little impact on survival. More effective treatments are desperately needed for this disease. Frondoside A is a triterpenoid glycoside isolated from the Atlantic sea cucumber, Cucumaria frondosa. Frondoside A potently inhibits pancreatic cancer cell growth and induces apoptosis in vitro and in vivo. The aim of the present study was to investigate whether frondoside A could enhance the anti-cancer effects of gemcitabine. Effects of frondoside A and gemcitabine alone and in combination on proliferation were investigated in two human pancreatic cancer cell lines, AsPC-1 and S2013. To investigate possible synergistic effects, combinations of low concentrations of the two drugs were used for a 72 h treatment period in vitro. Growth inhibition was significantly greater with the drug combinations than their additive effects. Combinations of frondoside A and gemcitabine were tested in vivo using the athymic mouse model. Xenografts of AsPC-1 and S2013 cells were allowed to form tumours prior to treatment with the drugs alone or in combination for 30 days. Tumours grew rapidly in placebo-treated animals. Tumour growth was significantly reduced in all treatment groups. At the lowest dose tested, gemcitabine (4 mg/kg/dose), combined with frondoside A (100 μg/kg/day) was significantly more effective than with either drug alone. To conclude: The present data suggest that combinations of frondoside A and gemcitabine may provide clinical benefit for patients with pancreatic cancer.

Cerebellar mutism: the rehabilitation challenge in pediatric neuro-oncology: case studies

Cerebellar Mutism Syndrome (CMS), also known as posterior fossa syndrome (CMS/PFS), refers to a transient loss of speech followed by dysarthria and is a common complication in the pediatric population following resection of a cerebellar tumor. Recognition and rehabilitation of CMS is critical in the post-operative phases of recovery. Two case studies, including neuropsychological assessments, along with the family and patient's perspectives are reviewed.

Changes in the brain accumulation of glucocorticoids in abcb1a-deficient CF-1 mice

The multidrug resistance transporter, P-glycoprotein (P-gp), contributes to highly lipophilic molecules penetrating the brain from the blood at a much lower rate than expected, and has numerous substrates, inhibitors and modulators. The drug-transporting isoform of P-gp is coded by a single human gene, ABCB1, and shares 80% homology with the murine drug-transporting isoforms, abcb1a and abcb1b, which share 92% homology with each other. Although these murine isoforms are highly similar, there are known affinity differences between the isoforms, and the localisation of the two isoforms in the brain is also disputed. Studies using mice genetically modified to be deficient in one or both isoforms of P-gp have also resulted in conflicting data. The contribution of the abcb1a isoform, which is considered to contribute most to the central nervous system (CNS)-protective role of P-gp, is investigated in the present study using CF-1-abcb1a(-/-) mice and the well-established brain/choroid plexus perfusion technique. Twenty-minute in situ brain/choroid plexus perfusions in CF-1-abcb1a(-/-) mice indicated the increased accumulation of [(3) H]cortisol, [(3) H]corticosterone and [(3) H]dexamethasone in most of the brain regions examined compared to CF-1-abcb1a(+/+) mice. Taken together with our earlier published studies in abcb1a/b(-/-) mice, these data strongly suggest that the in vivo CNS accumulation of glucocorticoids obtained using single knockout strains [e.g. abcb1a(-/-)] cannot be directly compared with those obtained in double knockout strains [e.g. abcb1a/b(-/-)].

Rectal taurocholate increases L cell and insulin secretion, and decreases blood glucose and food intake in obese type 2 diabetic volunteers

AIMS/HYPOTHESIS

Glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) are secreted from enteroendocrine L cells in response to numerous stimuli, including bile salts. Both have multiple effects that are potentially useful in treating diabetes and obesity. L cell number and hormone content in the intestine are highest in the rectum in humans. We investigated the effects of intrarectal sodium taurocholate on plasma GLP-1, PYY, insulin and glucose concentrations, and on food intake of a subsequent meal.

METHODS

Ten obese type 2 diabetic volunteers were each studied on five separate occasions after an overnight fast and oral administration of 100 mg sitagliptin 10 h before the study. They then received an intrarectal infusion of either one of four doses of taurocholate (0.66, 2, 6.66 or 20 mmol, each in 20 ml of vehicle) or vehicle alone (1% carboxymethyl cellulose) single-blind over 1 min. Hormone and glucose measurements were made prior to, and for 1 h following, the infusion. The consumption of a previously selected favourite meal eaten to satiety was measured 75 min after the infusion.

RESULTS

Taurocholate dose-dependently increased GLP-1, PYY and insulin, with 20 mmol doses resulting in peak concentrations 7.2-, 4.2- and 2.6-fold higher, respectively, than those achieved with placebo (p < 0.0001 for each). Plasma glucose decreased by up to 3.8 mmol/l (p < 0.001). Energy intake was decreased dose-dependently by up to 47% (p < 0.0001). The ED(50) values for effects on integrated GLP-1, insulin, PYY, food intake and glucose-lowering responses were 8.1, 10.5, 18.5, 24.2 and 25.1 mmol, respectively.

CONCLUSIONS/INTERPRETATION

Therapies that increase bile salts (or their mimics) in the distal bowel may be valuable in the treatment of type 2 diabetes and obesity.

Norepinephrine and ß₁-adrenergic signaling facilitate activation of hippocampal CA1 pyramidal neurons during contextual memory retrieval

We previously described a role for adrenergic signaling in the hippocampus to promote contextual and spatial memory retrieval. A subsequent study performing expression analysis of the immediate-early gene (IEG) Arc suggested that activation of CA1 but not CA3 pyramidal neurons during memory retrieval is impaired in the absence of NE. The current study sought to confirm and extend those observations by performing expression analysis of a second IEG product, Fos, following a much greater variety of testing conditions. In mutant mice lacking NE, induction of Fos was normal in all regions of the hippocampus and amygdala shortly after fear conditioning. In contrast, when testing contextual fear 1 day after training, induction of Fos in CA1 and the central nucleus of the amygdala (CeA), but not CA3, the dentate gyrus or other amygdaloid nuclei, was impaired in the mutant mice. This pattern corresponded to the memory retrieval deficit exhibited by these mice. On the other hand, induction was normal in CA1 and CeA when testing cued fear 1 day after training, or contextual fear 1 week or 1 month after training, conditions in which retrieval are normal in the absence of NE. Acute restoration of NE in the mutant mice before testing but not before training rescued retrieval of contextual fear and restored Fos induction in CA1 and CeA. Because NE facilitates retrieval through the activation of β(1)-adrenergic receptors, β(1) knockout mice were also examined and found to exhibit reduced induction of Fos in CA1 and CeA following retrieval. Based on these and previous results, we hypothesize that adrenergic signaling is critical for the full activation of CA1 pyramidal neurons in response to excitatory input from CA3 pyramidal neurons conveying retrieved contextual information.

Retinoic acid receptor-α signalling antagonizes both intracellular and extracellular amyloid-β production and prevents neuronal cell death caused by amyloid-β

Alzheimer’s disease (AD) is characterized by amyloid-β (Aβ) deposition in the brain, neuronal cell loss and cognitive decline. We show here that retinoic acid receptor (RAR)α signalling in vitro can prevent both intracellular and extracellular Aβ accumulation. RARα signalling increases the expression of a disintegrin and metalloprotease 10, an α-secretase that processes the amyloid precursor protein into the non-amyloidic pathway, thus reducing Aβ production. We also show that RARα agonists are neuroprotective, as they prevent Aβ-induced neuronal cell death in cortical cultures. If RARα agonists are given to the Tg2576 mouse, the normal Aβ production in their brains is suppressed. In contrast, neither RARβ nor γ-agonists affect Aβ production or Aβ-mediated neuronal cell death. Therefore, RARα agonists have therapeutic potential for the treatment of AD.

Validation of screening measures for assessing mood in stroke patients

PURPOSE

There are few validated measures to assess mood in stroke patients and even fewer suitable for all stroke patients, including those with communication problems. The aim of this study was to compare the Stroke Aphasic Depression Questionnaire Hospital version (SADQ-H), Signs of Depression Scale (SODS), Visual Analogue Mood Scale (VAMS) and Visual Analogue Self-esteem Scale (VASES) in screening for mood problems after stroke.

METHODS

Fifty healthy older adults and 100 stroke patients in hospital completed the VAMS and VASES. A nurse completed the SADQ-H and SODS in relation to the stroke patients. A relative/carer completed the SADQ-H and SODS in relation to the healthy older adults. Those without communication problems also completed the Hospital Anxiety and Depression Scale (HADS).

RESULTS

The internal consistency of the scales was low in healthy older adults. In stroke patients the internal consistency of the SADQ-H, VAMS, and VASES was high (alpha = .71-.84) but that of the SODS was low (alpha = .53). In healthy older adults, correlations between the HADS and the VAMS and VASES were high but low between the HADS and SADQ-H and SODS. In stroke patients, the HADS depression scale correlated significantly with all the scales (0.35-0.55) but only the SADQ-H 10, VAMS, and VASES were significantly correlated with the HADS anxiety scale (0.40-0.52). Appropriate cut-offs were found for the SADQ-H (17/18), SADQ-H 10 (5/6), SODS (1/2), and VAMS 'sad' item (22/23) in comparison to depression on the HADS. No appropriate cut-offs were identified in comparison to anxiety on the HADS.

CONCLUSIONS

The SADQ-H, SADQ-H10 and SODS were all appropriate for screening for possible depression after stroke but not for screening for possible anxiety. The SADQ-H 10 had greater internal consistency and higher sensitivity and specificity than the SODS and is shorter than the SADQ-H. It was also significantly correlated with both the anxiety and depression scales of the HADS. The SADQ-H 10 was therefore recommended as the most appropriate for screening purposes. The VAMS and VASES provided no clear cut-offs for use in screening but scores were highly correlated with the HADS. They are therefore more suitable for assessing severity of low mood rather than for screening purposes. The cut-offs identified need further validation in an independent sample of stroke patients, including a higher proportion with low mood.

Comparative outcomes following endoscopic ureteral detachment and formal bladder cuff excision in open nephroureterectomy for upper urinary tract transitional cell carcinoma

PURPOSE

The introduction of laparoscopic nephroureterectomy highlights the need for the critical appraisal of approaches to the distal ureter at surgery for upper tract transitional cell carcinoma. We compared differences after endoscopic ureteral detachment and open bladder cuff excision in nephroureterectomy.

MATERIALS AND METHODS

A total of 138 patients underwent open nephroureterectomy for upper urinary tract transitional cell carcinoma from 1982 to 2005 with a median followup of 43 months. Of these patients 90 underwent endoscopic ureteral detachment and 48 underwent bladder cuff excision. Demographic, perioperative and oncological outcome data were collected in all cases. Statistical analyses were performed using the Student t test, chi-square and log rank tests, and logistic and Cox regression.

RESULTS

Mean operative duration was significantly lower in the endoscopic detachment group than in the bladder cuff group (p <0.01). There were 49 (54.4%) bladder recurrences in the endoscopic detachment group, of which 8 (16.3%) were muscle invasive and 3 (3.3%) developed at the resection site. There were 23 (47.9%) bladder recurrences in the bladder cuff group, of which 3 (13.0%) were muscle invasive and 2 (4.2%) developed at the resection site. All 5 resection site tumors occurred after excision of muscle invasive distal ureteral tumors and 4 of these had positive margins. There were no differences in recurrence-free survival or disease specific survival between the groups. Operation subtype did not predict oncological outcome on univariate or multivariate analysis.

CONCLUSIONS

Endoscopic ureteral detachment reduces operative duration and is associated with equivalent oncological outcomes compared with open bladder cuff excision in nephroureterectomy. Caution should be exercised in patients with low ureteral tumors.

Quality of life and psychological status of patients with implantable cardioverter defibrillators

INTRODUCTION

Implantable cardioverter defibrillators (ICDs) are effective at reducing mortality in patients at high risk for sudden cardiac death (SCD) but can cause psychological distress and reduce quality of life (QOL). The full benefits of ICDs can only be achieved when the patient's QOL and psychological status are maintained. We examined psychological status and QOL post ICD implantation; the relationship of psychological status to QOL; the relationship of time since implantation to psychological status and QOL; and the relationship of time since ICD implantation and age of patient to these variables.

METHODS AND RESULTS

A cross-sectional self-administered assessment of QOL, depression, anxiety, demographic characteristics and cardiovascular health history of patients (n = 48) who had received ICDs within the past 10 years at an urban hospital. Patients who had ICDs for longer experienced worse depression and QOL. Patients who were younger had worse depression, anxiety, and QOL. The combination of anxiety, depression, age, and time since ICD implant significantly predicted overall QOL and the psychosocial and physical dimensions of QOL explaining 55.5, 54, and 34.9% of the variance, respectively.

CONCLUSION

Younger ICD patients are at highest risk for psychological distress and poor QOL. Longitudinal research would facilitate determination of the trajectory of changes in psychological status and QOL over the duration of the ICD experience.

Pressor responses to ephedrine are not impaired in dopamine beta-hydroxylase knockout mice

BACKGROUND AND PURPOSE

Ephedrine and amphetamine can cause substantial increases in systemic arterial pressure. However, the role of endogenous noradrenaline release in mediating the pressor response to ephedrine is controversial. Studies using pharmacologic agents to decrease the synthesis, storage, and release of catecholamines have supported both a direct and an indirect mechanism of action for ephedrine. The purpose of the present study was to determine if endogenous noradrenaline release is required for cardiovascular responses to ephedrine and amphetamine using a genetic mouse model.

EXPERIMENTAL APPROACH

Increases in systemic arterial pressure and heart rate in response to ephedrine and amphetamine were investigated and compared in dopamine beta-hydroxylase knockout (Dbh -/-) mice that cannot synthesize noradrenaline. Dbh +/- littermates have normal noradrenaline and adrenaline tissue levels, and served as controls in all experiments.

KEY RESULTS

In Dbh -/- mice the increases in systemic arterial pressure and heart rate in response to i.v. injections of ephedrine were not impaired whereas responses to amphetamine were markedly reduced, when compared with responses in Dbh +/- mice. The pressor response to tyramine was abolished whereas pressor responses to noradrenaline, phenylephrine, dopamine, and angiotensin II were similar in Dbh -/- and Dbh +/- mice.

CONCLUSIONS AND IMPLICATIONS

The present results in Dbh -/- mice provide support for the hypothesis that pressor responses to ephedrine are directly mediated whereas responses to amphetamine are dependent on the release of noradrenaline and suggest that Dbh +/- and Dbh -/- mice are useful for the study of direct and indirect mechanisms.

Nevirapine uptake into the central nervous system of the Guinea pig: an in situ brain perfusion study

The presence of human immunodeficiency virus (HIV) in the central nervous system (CNS) is associated with the development of HIV-1-associated dementia (HAD), a major cause of HIV-related mortality. To eradicate HIV in the CNS, anti-HIV drugs need to reach the brain and cerebrospinal fluid (CSF) in therapeutic concentrations. This involves passage through the blood-brain and blood-CSF barriers. Using a well established guinea pig in situ brain perfusion model, this study investigated whether nevirapine [6H-dipyrido(3,2-b:2',3'-e)(1,4)diazepin-6-one,11-cyclopropyl-5,11-dihydro-4-methyl], a non-nucleoside reverse transcriptase inhibitor (NNRTI), could effectively accumulate in the CNS. [(3)H]Nevirapine was coperfused with [(14)C]mannitol (a vascular/paracellular permeability marker) through the carotid arteries for up to 30 min, and accumulation in the brain, CSF, and choroid plexus was measured. [(3)H]Nevirapine uptake into the cerebrum was greater than uptake of [(14)C]mannitol, indicating significant passage across the blood-brain barrier and accumulation into the brain (this was further confirmed with capillary depletion and high-performance liquid chromatography analyses). Likewise, [(3)H]nevirapine showed a great ability to cross the blood-CSF barrier and accumulate in the CSF, compared with [(14)C]mannitol. The CNS accumulation of [(3)H]nevirapine was unaffected by 100 muM nevirapine, suggesting that passage across the blood-brain barrier can occur by diffusion. Furthermore, coperfusion with 100 muM efavirenz [2H-3,1-benzoxazin-2-one, 6-chloro-4-(cyclopropylethynyl)-1,4-dihydro-4-(trifluoromethyl)-, (4S)-; another NNRTI] did not significantly alter CNS accumulation of [(3)H]nevirapine, indicating that the efficacy of nevirapine in the CNS would not be altered by the addition of this drug to a combination therapy. Together, these data indicate that this anti-HIV drug should be beneficial in the eradication of HIV within the CNS and the subsequent treatment of HAD.

Cyclic AMP response element-binding protein is required for normal maternal nurturing behavior

Analysis of mice with targeted disruptions of fosB or the gene encoding dopamine beta-hydroxylase suggests that FosB and adrenergic signaling play critical roles in maternal nurturing behavior. The majority of neonates born to null females from either mutation fail to thrive, and virgin mutant females of both lines exhibit impaired pup retrieval. Considering whether FosB and adrenergic signaling might share a signaling pathway important for maternal behavior, we examined the role of a potential intermediary, cyclic AMP response element-binding protein (CREB). Here we report that approximately 40% of neonates (all heterozygous) born to mice lacking the major isoforms of CREB (Creb-alphaDelta-/-) died within several days of birth. In contrast, heterozygotes born to Creb-alphaDelta+/- females thrived. Cross-fostering demonstrated that neonates born to Creb-alphaDelta(-/dagger/-) females thrived when reared by wild-type females, and that Creb-alphaDelta-/- females were capable of rearing neonates whose maternal care was initiated by wild-type females. Further, virgin Creb-alphaDelta-/- females were deficient in pup retrieval despite exhibiting normal investigation of pups and of novel objects. No maternal behavior phenotype was present in mice with a null mutation of the cyclic AMP response element modulator (Crem) gene. Interestingly, the number of cells immunostaining for phospho-CREB (on Ser(133)) in the medial preoptic area of the hypothalamus, a key region for the expression of maternal behavior, increased nearly three-fold in wild-type mice following exposure to pups but not to novel objects. On the other hand, basal expression and induction of FosB in response to pup exposure appeared to be independent of CREB because levels were equivalent between wild-type and Creb-alphaDelta-/- females. These results implicate CREB in maternal nurturing behavior and suggest that CREB is not critical for expression or induction of FosB in adult virgin female mice.

Temporal and spatial variations in structural protein expression during the progression from stunned to hibernating myocardium

BACKGROUND

Dysfunctional and normally perfused remote regions show equal myolysis and glycogen accumulation in pig hibernating myocardium. We tested the hypothesis that these arose secondary to elevations in preload rather than ischemia.

METHODS AND RESULTS

Expression of structural protein (desmin, desmoplakin, titin, cardiotin, alpha-smooth muscle actin, lamin-A/C, and lamin-B2) in viable dysfunctional myocardium was analyzed by immunohistochemistry. We performed blinded analysis of paired dysfunctional left anterior descending coronary artery and normal remote subendocardial samples from stunned (24 hours; n=6), and hibernating (2 weeks; n=6) myocardium versus sham controls pigs (n=7). Within 24 hours, cardiac myocytes globally reexpressed alpha-smooth muscle actin. In stunned myocardium, cardiotin was globally reduced, whereas reductions in desmin were restricted to the dysfunctional region. Alterations progressed with the transition to hibernating myocardium, in which desmin, cardiotin, and titin were globally reduced. A qualitatively similar reorganization of cytoskeletal proteins occurred 3 hours after transient elevation of left ventricular end-diastolic pressure to 33+/-3 mm Hg.

CONCLUSIONS

Qualitative cardiomyocyte remodeling similar to that in humans with chronic hibernation occurs rapidly after a critical coronary stenosis is applied, as well as after transient elevations in left ventricular end-diastolic pressure in the absence of ischemia. Thus, reorganization of cytoskeletal proteins in patients with viable dysfunctional myocardium appears to reflect chronic and/or cyclical elevations in preload associated with episodes of spontaneous regional ischemia.

Anti-HIV drug distribution to the central nervous system

The introduction, in 1995, of highly active antiretroviral therapy (HAART) dramatically reduced the morbidity and mortality of HIV-infected patients. However, the brain remains a site of viral replication for HIV and thus is still an important target for antiretroviral agents. Consequently, a clear understanding of how the current anti-HIV drugs reach the CNS, and interact at the level of the blood-brain barrier and blood-CSF barrier, is important if we are to maximise viral suppression and improve clinical outcome. It would also contribute to the development of new anti-HIV drugs and the identification of transport inhibitors that could be used as adjuvant therapies. In this review we focus on the role of the blood-brain and blood-CSF barriers in the delivery of the main classes of approved anti-HIV drugs. Among these groups, the CNS distribution of the nucleoside reverse transcriptase inhibitors is the best characterised. It involves probenecid efflux transport mechanisms, which limit their brain delivery and probably their, neurological efficacy. Nevirapine and efavirenz, the commonly prescribed non-nucleoside reverse transcriptase inhibitors, can readily enter the CSF, however, it remains to be seen if a transport system is involved in their distribution. The protease inhibitors have only a limited ability to reach the CNS, with the majority of this class of drugs not even being detected in human CSF after administration. This is partly the result of their removal from the CNS by the efflux transporters; P-glycoprotein, and possibly multi-drug resistance associated protein (MRP).

Hepatic fibrogenesis requires sympathetic neurotransmitters

BACKGROUND AND AIMS

Hepatic stellate cells (HSC) are activated by liver injury to become proliferative fibrogenic myofibroblasts. This process may be regulated by the sympathetic nervous system (SNS) but the mechanisms involved are unclear.

METHODS

We studied cultured HSC and intact mice with liver injury to test the hypothesis that HSC respond to and produce SNS neurotransmitters to promote fibrogenesis.

RESULTS

HSC expressed adrenoceptors, catecholamine biosynthetic enzymes, released norepinephrine (NE), and were growth inhibited by alpha- and beta-adrenoceptor antagonists. HSC from dopamine beta-hydroxylase deficient (Dbh(-/-)) mice, which cannot make NE, grew poorly in culture and were rescued by NE. Inhibitor studies demonstrated that this effect was mediated via G protein coupled adrenoceptors, mitogen activated kinases, and phosphatidylinositol 3-kinase. Injury related fibrogenic responses were inhibited in Dbh(-/-) mice, as evidenced by reduced hepatic accumulation of alpha-smooth muscle actin(+ve) HSC and decreased induction of transforming growth factor beta1 (TGF-beta1) and collagen. Treatment with isoprenaline rescued HSC activation. HSC were also reduced in leptin deficient ob/ob mice which have reduced NE levels and are resistant to hepatic fibrosis. Treating ob/ob mice with NE induced HSC proliferation, upregulated hepatic TGF-beta1 and collagen, and increased liver fibrosis.

CONCLUSIONS

HSC are hepatic neuroglia that produce and respond to SNS neurotransmitters to promote hepatic fibrosis.

HIV evolution: CTL escape mutation and reversion after transmission

Within-patient HIV evolution reflects the strong selection pressure driving viral escape from cytotoxic T-lymphocyte (CTL) recognition. Whether this intrapatient accumulation of escape mutations translates into HIV evolution at the population level has not been evaluated. We studied over 300 patients drawn from the B- and C-clade epidemics, focusing on human leukocyte antigen (HLA) alleles HLA-B57 and HLA-B5801, which are associated with long-term HIV control and are therefore likely to exert strong selection pressure on the virus. The CTL response dominating acute infection in HLA-B57/5801-positive subjects drove positive selection of an escape mutation that reverted to wild-type after transmission to HLA-B57/5801-negative individuals. A second escape mutation within the epitope, by contrast, was maintained after transmission. These data show that the process of accumulation of escape mutations within HIV is not inevitable. Complex epitope- and residue-specific selection forces, including CTL-mediated positive selection pressure and virus-mediated purifying selection, operate in tandem to shape HIV evolution at the population level.

The involvement of the blood–brain and the blood–cerebrospinal fluid barriers in the distribution of leptin into and out of the rat brain

Leptin is a 16 kDa hormone that is produced by adipose tissue and has a central effect on food intake and energy homeostasis. The ability of leptin to cross the blood-brain and blood-cerebrospinal fluid (CSF) barriers and reach or leave the CNS was studied by the bilateral in situ brain perfusion and isolated incubated choroid plexus techniques in the rat. Brain perfusion results indicated that [(125)I]leptin reached the CNS at higher concentrations than the vascular marker, confirming that [(125)I]leptin crossed the brain barriers. Leptin distribution varied between CNS regions and indicated that the blood-brain barrier, in contrast to the blood-CSF route, was the key pathway for [(125)I]leptin to reach the brain. Further perfusion studies revealed that [(125)I]leptin movement into the arcuate nucleus, thalamus, frontal cortex, choroid plexuses and CSF was unaffected by unlabelled human or murine leptin at a concentration that reflects the upper human and rat plasma leptin concentration (2.5 nM). In contrast, the cerebellum uptake of [(125)I]leptin was decreased by 73% with 2.5 nM human leptin. Thus, this site of dense leptin receptor expression would be sensitive to physiological changes in leptin plasma concentrations. The highest rate (K(in)) of [(125)I]leptin uptake was into the choroid plexuses (307.7+/-68.0 microl/min/g); however, this was not reflected in the CSF (8.9+/-4.1 microl/min/g) and indicates that this tissue tightly regulates leptin distribution. The multiple-time brain uptake of [(125)I]leptin was non-linear and suggested leptin could also be removed from the CNS. Studies using the incubated rat choroid plexus model found that [(125)I]leptin could cross the apical membrane of the choroid plexus to leave the CSF. However, this movement was not sensitive to unlabelled human leptin or specific transport inhibitors/modulators (including probenecid, digoxin, deltorphin II, progesterone and indomethacin).This study supports the concept of brain-barrier regulation of leptin distribution to the CNS, and highlights an important link between leptin and the cerebellum.

The Distribution of the HIV Protease Inhibitor, Ritonavir, to the Brain, Cerebrospinal Fluid, and Choroid Plexuses of the Guinea Pig

Anti-human immunodeficiency virus (HIV) drug penetration into the brain and cerebrospinal fluid (CSF) is necessary to tackle HIV within the CNS. This study examines movement of [(3)H]ritonavir across the guinea pig blood-brain and blood-CSF barriers and accumulation within the brain, CSF, and choroid plexus. Ritonavir is a protease inhibitor, used in combination therapy (often as a pharmacoenhancer) to treat HIV. Drug interactions at brain barrier efflux systems may influence the CNS penetration of anti-viral drugs, thus the influence of additional protease inhibitors, nucleoside reverse transcriptase inhibitors, and non-nucleoside reverse transcriptase inhibitors on [(3)H]ritonavir CNS distribution was explored. Additionally, the involvement of transporters on [(3)H]ritonavir passage across the brain barriers was assessed. Results from in situ brain perfusions and capillary depletion analysis demonstrated that [(3)H]ritonavir uptake into the guinea pig brain was considerable (6.6 +/- 0.7 ml/100 g at 30 min, vascular space corrected), although a proportion of drug remained trapped in the cerebral capillaries and did not reach the brain parenchyma. CSF uptake was more limited (2.2 +/- 0.4 ml/100 g at 30 min), but choroid plexus uptake was abundant (176.7 +/- 46.3 ml/100 g at 30 min). [(3)H]Ritonavir brain and CSF uptake was unaffected by neither inhibitors of organic anion transport (probenecid and digoxin) or P-glycoprotein (progesterone), nor by any additional anti-HIV drugs, indicating that brain barrier efflux systems do not significantly limit brain or CSF [(3)H]ritonavir accumulation in this model. [(3)H]Ritonavir uptake into the perfused choroid plexus was significantly reduced by nevirapine and abacavir, additional perfusion studies, and isolated incubated choroid plexus experiments were carried out in an attempt to further characterize the transporter involved.

Hydroxyurea transport across the blood-brain and blood-cerebrospinal fluid barriers of the guinea-pig

Hydroxyurea is used in the treatment of HIV infection in combination with nucleoside analogues, 2'3'-didehydro-3'deoxythymidine (D4T), 2'3'-dideoxyinosine or abacavir. It is distributed into human CSF and is transported from the CSF to sub-ependymal brain sites, but its movement into the brain directly from the blood has not been studied. This study addressed this by a brain perfusion technique in anaesthetized guinea-pigs. The carotid arteries were perfused with an artificial plasma containing [14C]hydroxyurea (1.6 microm) and a vascular marker, [3H]mannitol (4.6 nm). Brain uptake of [14C]hydroxyurea (8.0 +/- 0.9%) was greater than [3H]mannitol (2.4 +/- 0.2%; 20-min perfusion, n = 8). CSF uptake of [14C]hydroxyurea (5.6 +/- 1.5%) was also greater than [3H]mannitol (0.9 +/- 0.3%; n = 4). Brain uptake of [14C]hydroxyurea was increased by 200 microm hydroxyurea, 90 microm D4T, 350 microm probenecid, 25 microm digoxin, but not by 120 microm hydroxyurea, 16.5-50 microm D4T, 90 microm 2'3'-dideoxyinosine or 90 microm abacavir. [14C]Hydroxyurea distribution to the CSF, choroid plexus and pituitary gland remained unaffected by all these drugs. The metabolic half-life of hydroxyurea was > 15 h in brain and plasma. Results indicate that intact hydroxyurea can cross the brain barriers, but is removed from the brain by probenecid- and digoxin-sensitive transport mechanisms at the blood-brain barrier, which are also affected by D4T. These sensitivities implicate an organic anion transporter (probably organic anion transporting polypeptide 2) and possibly p-glycoprotein in the brain distribution of hydroxyurea and D4T.

Effect of transport inhibitors and additional anti-HIV drugs on the movement of lamivudine (3TC) across the guinea pig brain barriers

To treat human immunodeficiency virus (HIV) within the central nervous system (CNS), levels of anti-HIV drugs in the brain must reach therapeutic concentrations. The ability of (-)-2'-deoxy-3'-thiacytidine (3TC; lamivudine) to cross the blood-brain and blood-cerebrospinal fluid (CSF) barriers, alone and in combination with additional nucleoside analogs, was investigated. The bilateral in situ guinea pig brain perfusion method, linked to high-performance liquid chromatography analyses, was used to examine 3TC uptake into brain and CSF simultaneously. The influence of transport inhibitors and additional nucleoside analogs on this uptake was investigated. 3TC movement across the blood-CSF barrier was examined in more detail by the isolated choroid plexus model. 3TC movement across the brain barriers and subsequent accumulation in the brain and CSF was low. However, 3TC uptake from blood into choroid plexus (a potential CNS target for HIV treatment) was significant, and was facilitated by a digoxin-sensitive transporter. Another transporter was identified, which removed 3TC from the choroid plexus. Abacavir, 2'3'-didehydro-3'deoxythymidine, and 3'-azido 3'-deoxythymidine did not interact with 3TC at either of the brain barriers to affect CNS concentrations of 3TC. However, a significant interaction between 3TC and 2'3'-dideoxyinosine was observed at the choroid plexus, and it may prove beneficial to select drug combinations where no such interaction is indicated.

Mechanisms by which 2',3'-dideoxyinosine (ddI) crosses the guinea-pig CNS barriers; relevance to HIV therapy

The influence of transport mechanisms at the blood-brain barrier (BBB) and blood-CSF barrier (choroid plexus) on the CNS distribution of anti-human immunodeficiency virus (HIV) drugs was examined using guinea-pig brain perfusion and incubated choroid plexus models. 2',3'-dideoxyinosine (ddI) passage across the BBB was demonstrated to be via non-saturable (Kd = 0.22 +/- 0.3 microL/min/g) and saturable (Km = 20.1 +/- 15.0 microm, Vmax = 6.5 +/- 2.1 pmol/min/g) processes. Cross competition studies implicated an equilibrative nucleoside transporter in this influx. The brain distribution of ddI was unchanged in the presence of additional nucleoside reverse transcriptase inhibitors (NRTIs). ddI transport from blood into choroid plexus was demonstrated to involve an organic anion transporting polypeptide 2-like transporter. The NRTIs, abacavir, 3'-azido 3'-deoxythymidine and (-)-beta-L-2',3'-dideoxy-3'-thiacytidine, competed with ddI for transporter binding sites at the choroid plexus, altering the tissue concentration of ddI. This has clinical implications as the choroid plexus is a site of HIV replication, and suboptimal CNS concentrations of anti-HIV drugs could result in neurological complications. Furthermore, this may promote the selection of drug resistant variants of HIV within the CNS, which could re-infect the periphery and lead to HIV therapy failure. This study indicates that understanding drug interactions at the transporter level could prove valuable when selecting drug combinations to treat HIV within the CNS.

The distribution of the anti-HIV drug, 2'3'-dideoxycytidine (ddC), across the blood-brain and blood-cerebrospinal fluid barriers and the influence of organic anion transport inhibitors

The brain and CSF distribution of the HIV reverse transcriptase inhibitor, 2'3'-dideoxycytidine (ddC), was investigated by the in situ brain perfusion and isolated incubated choroid plexus methods in the guinea pig. Multiple-time brain perfusions indicated that the distribution of [3H]ddC to the brain and CSF was low and the unidirectional rate constant (K(in)) for the brain uptake of this nucleoside analogue (0.52 +/- 0.10 microL/min/g) was not significantly different to that for the vascular marker, [14C]mannitol (0.44 +/- 0.09 microL/min/g). The influence of unlabelled ddC, six organic anion transport inhibitors and 3'-azido 3'-deoxythymidine (AZT) on the CNS uptake of [3H]ddC was examined in situ and in vitro. ddC, probenecid and 2,4-dichlorophenoxyacetic acid altered the distribution of [3H]ddC into the brain and choroid plexuses, indicating that the limited distribution of [3H]ddC was a result of an organic anion efflux transporter, in addition to the low lipophilicity of this drug (octanol-saline partition coefficient, 0.047 +/- 0.001). The CNS distribution was also sensitive to p-aminohippurate and deltorphin II, but not digoxin, suggesting the involvement of organic anion transporters (OAT1/OAT3-like) and organic anion transporting polypeptides (OATP1/OATPA-like). AZT did not effect the accumulation of [3H]ddC, indicating that when these nucleoside analogues are used in anti-HIV combination therapy, the CNS distribution of ddC is unchanged.

Nitrogen retention in headwater streams: the influence of groundwater-surface water exchange

Groundwater-surface water (GW-SW) interaction lengthens hydraulic residence times, increases contact between solutes and biologically active surfaces, and often creates a gradient of redox conditions conducive to an array of biogeochemical processes. As such, the interaction of hydraulic patterns and biogeochemical activity is suspected to be an important determinant of elemental spiraling in streams. Hydrologic interactions may be particularly important in headwater streams, where the extent of the GW-SW mixing environment (i.e., hyporheic zone) is proportionately greater than in larger streams. From our current understanding of stream ecosystem function, we discuss nitrogen (N) spiraling, present a conceptual model of N retention in streams, and use both of these issues to generate specific research questions and testable hypotheses regarding N dynamics in streams.

Important role of endogenous norepinephrine and epinephrine in the development of in vivo pressure-overload cardiac hypertrophy

OBJECTIVES

We sought to define the role of norepinephrine and epinephrine in the development of cardiac hypertrophy and to determine whether the absence of circulating catecholamines alters the activation of downstream myocardial signaling pathways.

BACKGROUND

Cardiac hypertrophy is associated with elevated plasma catecholamine levels and an increase in cardiac morbidity and mortality. Although considerable evidence suggests that G-protein-coupled receptors are involved in the hypertrophic response, it remains controversial whether catecholamines are required for the development of in vivo cardiac hypertrophy.

METHODS

We performed transverse aortic constriction (TAC) in dopamine beta-hydroxylase knockout mice (Dbh(-/-), genetically altered mice that are completely devoid of endogenous norepinephrine and epinephrine) and littermate control mice. After induction of cardiac hypertrophy, the mitogen-activated protein kinase (MAPK) signaling pathways were measured in pressure-overloaded/wild-type and Dbh(-/-) hearts.

RESULTS

Compared with the control animals, cardiac hypertrophy was significantly blunted in Dbh(-/-) mice, which was not associated with altered cardiac function, as assessed by transthoracic echocardiography in conscious mice. The extracellularly regulated kinase (ERK 1/2), c-jun-NH(2)-terminal kinase (JNK) and p38 MAPK pathways were all activated by two- to threefold after TAC in the control animals. In contrast, induction of the three pathways (ERK 1/2, JNK and p38) was completely abolished in Dbh(-/-) mice.

CONCLUSIONS

These data demonstrate a nearly complete requirement of endogenous norepinephrine and epinephrine for the induction of in vivo pressure-overload cardiac hypertrophy and for the activation of hypertrophic signaling pathways.

Transport characteristics of the anti-human immunodeficiency virus nucleoside analog, abacavir, into brain and cerebrospinal fluid

The role of the blood-brain and blood-cerebrospinal fluid (CSF) barriers in the distribution of anti-human immunodeficiency virus (HIV) drugs is integral to the design of effective treatment regimens for HIV infection within the brain. Abacavir (formerly 1592U89) is a nucleoside analog reverse transcriptase inhibitor, which has activity against HIV. The ability of this drug to reach the brain at therapeutic concentrations has been explored by means of an established bilateral in situ brain perfusion model in combination with high-performance liquid chromatography analysis in the anesthetized guinea pig. The influence of other drugs on the entry of abacavir into the brain was also investigated and is of special significance with the use of three of more anti-HIV drugs as the recommended treatment for HIV infection. The results of this study indicate that intact [(14)C]abacavir can cross the blood-brain and blood-CSF barriers and enter the brain and cisternal CSF. Further studies, at a perfusion time of 10 min, revealed that the uptake (R(cerebrum)) of this (14)C-labeled drug (10.1 +/- 0.6%) was not affected by the presence of 0.86 to 200 microM unlabeled abacavir (6.8 microM; 11.0 +/- 1.4%), the nucleoside transport inhibitor [10 microM 6-(4-nitrobenzyl)thio-9-beta-D-ribofuranosylpurine; 9.7 +/- 3.3%], or a substrate for the nucleobase transporter (100 microM adenine; 12.7 +/- 3.0%). This would suggest that the entry of abacavir into the brain would not be affected by the presence of other anti-HIV drugs. The results of this animal study indicate that abacavir would be a useful addition to a treatment regimen against HIV-infection within the brain.

Use of dopamine-beta-hydroxylase-deficient mice to determine the role of norepinephrine in the mechanism of action of antidepressant drugs

Norepinephrine (NE) is thought to play an important role in the pathophysiology of depression, and in the mechanism of action of antidepressant compounds. Previously, we created mice that are unable to synthesize NE and epinephrine due to targeted disruption of the dopamine-beta-hydroxylase gene (Dbh). To specifically test the role of NE in mediating behavioral changes elicited by antidepressants, these mice were examined in the forced swim test. There was no difference in baseline immobility scores in the forced swim test between Dbh(+/-) mice, which have normal levels of NE, and Dbh(-/-) mice. However, the Dbh(-/-) mice failed to demonstrate antidepressant-like behavioral effects following the administration of several classes of antidepressants. These included the NE reuptake inhibitors desipramine and reboxetine, the monoamine oxidase inhibitor pargyline, and the atypical antidepressant bupropion. In addition, desipramine significantly reduced immobility in the Dbh(-/-) mice following pretreatment with the synthetic NE precursor L-threo-3,4-dihydroxyphenylserine, but not saline. Biochemical studies showed that there was no significant difference in the regional brain levels of NE transporter immunoreactivity or monoamine oxidase activity, the primary targets for most of the compounds examined. Taken together, these data show that the use of mice that lack endogenous NE may be an important strategy for unraveling the role of NE in tests sensitive to the effects of various psychotherapeutic agents.

Complications of fluoroscopically guided caudal epidural injections

OBJECTIVES

To assess the incidence of complications of fluoroscopically guided caudal epidural injections.

DESIGN

A retrospective cohort design study in which chart review was performed on patients, who presented with radiculopathy and received fluoroscopically guided caudal epidural steroid injections. All injections were performed consecutively over a 12-mo period. An independent observer reviewed medical charts, which included a 24-hr post procedure telephone call by an ambulatory surgery center nurse, who asked a standardized questionnaire about complications after the injections. Physician follow-up office notes 1 to 3 wk after injection along with epidurograms were reviewed.

RESULTS

The charts of 139 patients, who received 257 injections, were reviewed. Complications per injection included 12 episodes of insomnia the night of the injection (4.7%), 9 transient nonpositional headaches that resolved within 24 hr (3.5%), 8 increased back pain (3.1%), 6 facial flushing (2.3%), 2 vasovagal reactions (0.8%), 2 episodes of nausea (0.8%), and 1 increased leg pain (0.4%). No dural punctures occurred.

CONCLUSIONS

No major complications occurred. The incidence of minor complications was 15.6% per injection. All reactions resolved without morbidity and no patient required hospitalization.

The kinetics of hypoxanthine efflux from the rat brain

The brain efflux of radiolabelled hypoxanthine in the rat was rapid in the first minute after injection [K(eff)(i)=0.21+/-0.06 min(-1)], which was saturable with a V(max)=13.08+/-0.81 nM min(-1) g(-1), and a high K(m,app) (67.2+/-13.4 microM); the K(i,app) for inosine was 31.5+/-7.6 microM. Capillary depletion analysis indicated that hypoxanthine accumulates in neurons and glia with the time. From cross-inhibition studies with different purines and pyrimidines, it suggests that these molecules could also be important substrates for this carrier.

Leptin transport at the blood--cerebrospinal fluid barrier using the perfused sheep choroid plexus model

Leptin is secreted by adipose tissue and thought to regulate appetite at the central level. Several studies have explored the central nervous system (CNS) entry of this peptide across the blood-brain and blood-cerebrospinal fluid (CSF) barriers in parallel, but this is the first to explore the transport kinetics of leptin across the choroid plexus (blood-CSF barrier) in isolation from the blood-brain barrier (BBB). This is important as the presence of both barriers can lead to ambiguous results from transport studies. The model used was the isolated Ringer perfused sheep choroid plexus. The steady-state extraction of [(125)I]leptin (7.5 pmol l(-1)) at the blood face of the choroid plexus was 21.1+/-5.7%, which was greater than extraction of the extracellular marker, giving a net cellular uptake for [(125)I]leptin (14.0+/-3.7%). In addition, trichloroacetic acid precipitable [(125)I] was detected in newly formed CSF, indicating intact protein transfer across the blood-CSF barrier. Human plasma concentrations of leptin are reported to be 0.5 nM. Experiments using 0.5 nM leptin in the Ringer produced a concentration of leptin in the CSF of 12 pM (similar to that measured in humans). [(125)I]Leptin uptake at the blood-plexus interface using the single-circulation paired tracer dilution technique (uptake in <60 s) indicated the presence of a saturable transport system, which followed Michaelis-Menten-type kinetics (K(m)=16.3+/-1.8 nM, V(max)=41.2+/-1.4 pmol min(-1) g(-1)), and a non-saturable component (K(d)=0.065+/-0.002 ml min(-1) g(-1)). In addition, secretion of new CSF by the choroid plexuses was significantly decreased with leptin present. This study indicates that leptin transport at the blood-CSF barrier is via saturable and non-saturable mechanisms and that the choroid plexus is involved in the regulation of leptin availability to the brain.

Community values and preferences in transplantation organ allocation decisions

This paper is concerned with community values and preferences in organ transplantation allocation decisions. With recent trends in organ shortages, transplant teams face difficult allocation decisions amongst increasing numbers of "worthy" potential recipients. It is argued that the debate about these decisions ought to be informed in part by a systematic knowledge of prevailing community standards. A community sample of 238 adults (140 women and 98 men, with a mean age of 47.0 years) completed a questionnaire concerning which factors ought to affect recipient priority for transplantation. Longer waiting time, better prognosis, younger age and being a parent were the most frequently selected criteria for organ allocation decisions. The participants also rank ordered 16 potential recipients presented in the form of case scenarios in terms of priority for transplantation. The 16 case scenarios were constructed from a factorial combination of four variables: age of recipient (young vs old); the time the recipient had been on a waiting list (long vs short); recipient prognosis (excellent vs fair); and parental status (children vs no children). It was found that one case scenario involving a young parent with an excellent prognosis and long waiting time was ranked first by 75.2% of all participants. Analysis revealed that transplant recipient age and prognosis were the most influential factors in determining the priority rankings for organ allocation. The study has demonstrated that judgement and decision analysis procedures can be used to elicit community values and preferences about complex resource allocation decisions.

Living with an implantable cardioverter-defibrillator: a review of the current literature related to psychosocial factors

Sudden cardiac death (SCD) is responsible for 300,000 deaths annually. Lethal ventricular dysrhythmias account for the majority of SCDs. Implantable cardioverter-defibrillators (ICDs) are the emerging treatment for lethal dysrhythmias. Although reductions in SCD mortality with ICDs are clear, the psychologic and social consequences of these devices reveal a mixed success. Patients with ICDs have high levels of anxiety and depressive symptoms. Conversely, most studies of quality of life in patients with ICDs report that the device is well accepted despite fears of being shocked. The ICD shocks are a unique aspect of treatment and have the potential to cause psychologic distress. Nursing needs to provide care from a holistic perspective. Support groups provide reassurance and allow patients to discuss expectations and fears related to the ICD. Research needs to be conducted to explore the impact of these devices on the lives of patients and their families.

The characteristics of nucleobase transport and metabolism by the perfused sheep choroid plexus

The uptake of nucleobases was investigated across the basolateral membrane of the sheep choroid plexus perfused in situ. The maximal uptake (U(max)) for hypoxanthine and adenine, was 35.51+/-1.50% and 30.71+/-0.49% and for guanine, thymine and uracil was 12.00+/-0.53%, 13.07+/-0.48% and 12.30+/-0.55%, respectively with a negligible backflux, except for that of thymine (35.11+/-5.37% of the U(max)). HPLC analysis revealed that the purine nucleobase hypoxanthine and the pyrimidine nucleobase thymine can pass intact through the choroid plexus and enter the cerebrospinal fluid CSF so the lack of backflux for hypoxanthine was not a result of metabolic trapping in the cell. Competition studies revealed that hypoxanthine, adenine and thymine shared the same transport system, while guanine and uracil were transported by a separate mechanism and that nucleosides can partially share the same transporter. HPLC analysis of sheep CSF collected in vivo revealed only two nucleobases were present adenine and hypoxanthine; with an R(CSF/Plasma) 0.19+/-0.02 and 3.43+/-0.20, respectively. Xanthine and urate, the final products of purine catabolism, could not be detected in the CSF even in trace amounts. These results suggest that the activity of xanthine oxidase in the brain of the sheep is very low so the metabolic degradation of purines is carried out only as far as hypoxanthine which then accumulates in the CSF. In conclusion, the presence of saturable transport systems for nucleobases at the basolateral membrane of the choroidal epithelium was demonstrated, which could be important for the distribution of the salvageable nucleobases, adenine and hypoxanthine in the central nervous system.

Modeling the potential radionuclide transport by the Ob and Yenisey Rivers to the Kara Sea

A major portion of the former Soviet Union (FSU) nuclear program is located in the West Siberian Basin. Among the many nuclear facilities are three production reactors and the spent nuclear fuel reprocessing sites, Mayak, Tomsk-7, and Krasnoyarsk-26, which together are probably responsible for the majority of the radioactive contamination found in the Ob and Yenisey River systems that feed into the Arctic Ocean through the Kara Sea. This manuscript describes ongoing research to estimate radionuclide fluxes to the Kara Sea from these river systems. Our approach is to apply a hierarchy of simple models that use existing and forthcoming data to quantify the transport and fate of radionuclide contaminants via various environmental pathways. We present an initial quantification of the contaminant inventory, hydrology, meteorology, and sedimentology of the Ob River system and preliminary conclusions from portions of the Ob River model.

Synthetic strands of neonatal mouse cardiac myocytes: structural and electrophysiological properties

The aim of the present study was to morphologically and electrically characterize synthetic strands of mouse ventricular myocytes. Linear strands of mouse ventricular myocytes with widths of 34.7+/-4.4 microm (W(1)), 57.9+/-2.5 microm (W(2)), and 86.4+/-3. 6 microm (W(3)) and a length of 10 mm were produced on glass coverslips with a photolithographic technique. Action potentials (APs) were measured from individual cells within the strands with cell-attached microelectrodes. Impulse propagation and AP upstrokes were measured with multisite optical mapping (RH237). Immunostaining was performed to assess cell-cell connections and myofibril arrangement with polyclonal antisera against connexin43 and N-cadherins and monoclonal antibodies against cardiac myosin. Light microscopy and myosin staining showed dense growth of well-developed elongated myocytes with lengths of 34.2+/-4.2 microm (W(1)), 36. 9+/-5.8 microm (W(2)), and 43.7+/-6.9 microm (W(3)), and length/width ratios of 3.9+/-0.2. Gap junctions were distributed around the cell borders (3 to 4 junctions/microm(2) cell area). Each cell was connected by gap junctions to 6.5+/-1.1 neighboring cells. AP duration shortened with time in culture (action potential duration at 50% repolarization: day 4, 103+/-34 ms; day 8, 16+/-3 ms; P:<0.01). Minimum diastolic potential and AP amplitude were 71+/-5 and 97.2+/-7.6 mV, respectively. Conduction velocity and the maximum dV/dt of the AP upstroke were 43.9+/-13.6 cm/s and 196+/-67 V/s, respectively. Thus, neonatal ventricular mouse myocytes can be grown in continuous synthetic strands. Gap junction distribution is similar to the neonatal pattern observed in the hearts of larger mammals. Conduction velocity is in the range observed in adult mice and in the higher range for mammalian species probably due to the higher dV/dt(max). This technique will permit the study of propagation, AP, and structure-function relations at cellular resolution in genetically modified mice.

Synthesis of 1,3-diynes via palladium-catalyzed reaction of 1, 1-dibromo-1-alkenes

[reaction: see text] Both symmetric and unsymmetric 1,3-diynes were prepared from the palladium-catalyzed reaction of 1,1-dibromo-1-alkenes. The formation of symmetric 1,3-diynes 2 (homocoupling) was catalyzed by a weak ligand, tris(2-furyl)phosphine (TFP), and the addition of catalytic amount of CuI accelerated the reaction. The synthesis of unsymmetric 1,3-diynes 4 (the Sonogashira reaction) required a highly electron rich tris(4-methoxyphenyl)phosphine as the ligand, and CuI promotes the formation of byproduct 1,1-diynyl-1-alkenes 5.

Smoking patterns, health behaviors, and health-risk behaviors of college women

In 1993, 22% of college women smoked; in 1997, the rate increased to 29%. College-age women (<24 years) showed the greatest increase in smoking. The purpose of this study is to describe smoking behaviors of college women. The sample included 21 college-age female smokers. Each woman was interviewed about smoking habits and completed a health survey, the Fagerstrom Test for Nicotine Dependence, a Self-Efficacy Scale for predicting smoking relapse, a Decisional Balance Scale for smoking, a readiness for change tool, and the Derogatis Stress Profile. The majority of the students began smoking at the age of 14 years or younger and smoked fewer than 10 cigarettes per day. The biggest obstacles to quitting were being around other smokers and social activities involving alcohol. These students did not smoke when ill and were interested in quitting smoking. Smoking frequency correlated significantly with dependency and stage of change. Advanced practice nurses have a unique opportunity to identify these young smokers, educate them about smoking-cessation options, and offer specific strategies to help these women stop smoking.

Total synthesis and antifungal evaluation of cyclic aminohexapeptides

The need for new therapies to treat systemic fungal infections continues to rise. Naturally occurring hexapeptide echinocandin B (1) has shown potent antifungal activity via its inhibition of the synthesis of beta-1,3 glucan, a key fungal cell wall component. Although this series of agents has been limited thus far based on their physicochemical characteristics, we have found that the synthesis of analogues bearing an aminoproline residue in the 'northwest' position imparts greatly improved water solubility (> 5 mg/mL). The synthesis and structure-activity relationships (SAR) based on whole cell and upon in vivo activity of the series of compounds are reported.

State and territorial boards of nursing approaches to the use of unlicensed assistive personnel

This study examined U.S. state and territorial boards of nursing approaches to the regulation of the use of: unlicensed assistive personnel (UAP) in acute care hospitals; state and jurisdictional authority, oversight and disciplinary action related to registered nurse (RN) delegation, supervision and assignment; educational preparation requirements for UAP; and future projections for their use. A survey was administered to 53 state and territorial boards of nursing officials in 1998. A majority of the states reported that they had regulations/guidelines for RN's who supervised UAP and regulations that protected the use of the RN title. Few states used the American Nurses Association or National Council of State Boards of Nursing definitions for delegation, supervision, or assignment. The majority have formulated their own definitions. The majority of states reported no standardized curriculum in place for UAP employed in acute care hospitals. More than half of the states reported that no plans existed for developing a curriculum.

Perceptions of registered nurses working with assistive personnel in the United Kingdom and the United States

This study examines registered nurse perceptions of their role in acute care hospitals that use nursing care assistants (NCA) and unlicensed assistive personnel (UAP). Also studied was registered nurse (RN) satisfaction with nursing care assistants and unlicensed assistive personnel in the United Kingdom (UK) and the United States of America (USA). The purpose of this study is to assist RNs and managers in the re-design of health-care delivery systems by investigating: 1. The differences and similarities of registered nurses in the UK and the USA in the perceptions of changes in the RN role when working with nursing care assistants or unlicensed assistive personnel. 2. The differences between and similarities of registered nurses in the UK and the USA in perceptions of NCA and UAP abilities to perform delegated duties, to communicate pertinent clinical information and to provide more time for professional nursing activities. Registered nurse perceptions in the UK were compared with the findings of a previous study of RN role changes and satisfaction in the USA. Registered nurses in the UK did not perceive a profound change in their role when working with UAP and were more satisfied with their use than were RNs in the USA.

The provision of preventive care by general practitioners measured by patient completed questionnaires

The objective of this study was, by means of patient self-report, to measure the provision of preventive care to patients of a sample of Australian general practitioners. Patient-completed questionnaires from a consecutive sample of Australian general practitioners enrolled in the Quality Assurance and Continuing Medical Education Program of the Royal Australian College of General Practitioners were used. Patients were attendees at Australian general practices. The main outcome measures included the following: the provision of tetanus immunization within the last 10 years; blood pressure measurement within the last 12 months; cholesterol screening within the past 5 years; provision of adequate information to enable patients to stop smoking if they desired; discussion about the benefits of diet and exercise to enhance life, and about alcohol intake; provision of cervical smears in the past 2 years; provision of adequate instruction in breast self-examination and overall satisfaction with service provision. A total of 12,605 questionnaires from 133 general practices were completed. There was wide variability between practices in the reported provision of preventive care items including an average of 86% (range 36-100) of patients reporting the provision of blood pressure checking in the past 12 months, 62% (range 25-97%) reporting the provision of tetanus immunization in the past 10 years, and 63% (range 10-91%) reporting having had a cervical smear in the past 2 years. Patients who were very satisfied were more likely to have reported that they had received blood pressure measurement in the past 12 months, participated in discussions about the benefits of diet and exercise in enhancing life, and participated in discussions about alcohol intake and provision of adequate instruction in the technique of breast self-examination. Patient self-reporting identified variability between practitioners in the provision of preventive care conforming to accepted guidelines. Patients who reported that they were very satisfied or who regularly attend only one general practice reported the provision of more preventive care than those who were not very satisfied or who regularly visited two or more general practitioners.