Resolving the composite trait of hypertension into its pharmacogenetic determinants by acute pharmacological modulation of blood pressure regulatory systems

Acute pharmacogenetic analysis was carried out in an intercross F2 population derived from Prague hypertensive-hypertriglyceridemic and Lewis rats. Quantitative trait loci (QTL) mapping was performed for baseline blood pressure (BP) and for BP after blockade of the renin-angiotensin system by losartan, of the sympathetic nervous system (SNS) by pentolinium, and of the nitric oxide system by N(G)-nitro- L-arginine methyl ester. Two significant loci for baseline BP were found on chromosome (Chr) 3 (logarithm of likelihood, LOD, 3.8) and Chr 5 (LOD 3.6), and one suggestive locus on Chr 1 (LOD 2.7). The QTL on Chr 3 persisted after treatment with the three agents while the QTL on Chr 5 and Chr 1 disappeared after pentolinium administration. This suggests independence of the locus on Chr 3 from each acute BP regulatory system examined, whereas the loci on Chr 5 and Chr 1 appeared to be controlled mainly by the SNS. Although not apparent at baseline, a significant locus appeared on Chr 8 (LOD 7.0) after blockade of the SNS, and NO system blockade led to the appearance of a new QTL on Chr 1 (LOD 3.6), indicating the contribution of the inhibited systems to these loci. Pharmacogenetic dissection of the BP trait is a powerful tool to unravel the underlying physiological mechanisms of QTL affecting baseline BP and to identify specific QTL for the response to drugs. This pharmocogenetic approach enabled us to determine the main causative acute BP regulatory systems and should lead to better selection of suitable antihypertensive drugs for individual patients.     

Mothers’ Intentions to Support Children’s Physical Activity Related to Attention and Implicit Agreement with Advertisements

Background

ParticipACTION’s Think Again campaign targeted mothers who think their children are sufficiently active, yet whose children do not achieve recommended amounts of physical activity.

Purpose

This research examined the relationship of mothers’ intentions to support children’s physical activity with explicit believability and implicit agreement with the Think Again campaign message, attention paid to the advertisement, involvement with the issue, concern regarding children’s inactivity, and attitudes.

Method

Participants were mothers from Edmonton, Canada (N?=?102) who viewed one Think Again advertisement then completed a measure of implicit agreement with the campaign message and questionnaires.

Results

The mothers who paid attention to the message and were concerned for their own children were more likely to intend to act on campaign messages. The majority of participants implicitly agreed that children’s physical inactivity was a problem, but there was less agreement that physical inactivity was a problem for their own children.

Conclusion

Participants automatically tended to agree with campaign messages when the focus was on children in general, but there was greater disagreement when asked about participant’s own children. Why most mothers were not in agreement with the reality of how much physical activity their children needs remains to be determined.     

Depression and anxiety symptoms: onset, developmental course and risk factors during early childhood

Background:  Depressive and anxiety disorders are among the top ten leading causes of disabilities. We know little, however, about the onset, developmental course and early risk factors for depressive and anxiety symptoms (DAS).
Objective:  Model the developmental trajectories of DAS during early childhood and to identify risk factors for atypically high DAS.
Method:  Group-based developmental trajectories of DAS conditional on risk factors were estimated from annual maternal ratings (1½ to 5 years) in a large population sample ( n  =   1759).
Results:  DAS increased substantially in two of the three distinct trajectory groups identified: High-Rising (14.7%); Moderate-Rising (55.4%); and Low (29.9%). Two factors distinguished the High-Rising group from the other two: Difficult temperament at 5 months (High-Rising vs Moderate-Rising: OR = 1.32; 95% CI = 1.13–1.55; High-Rising vs Low: OR = 1.31, CI = 1.12–1.54) and maternal lifetime major depression (High-Rising vs Moderate-Rising: OR = 1.10; CI = 1.01–1.20; High-Rising vs Low: OR = 1.19; CI = 1.08–1.31). Two factors distinguished the High-Rising group from the Low group: High family dysfunction (OR = 1.24; CI = 1.03–1.5) and Low parental self-efficacy (OR = .71; CI = .54–.94).
Conclusions:  DAS tend to increase in frequency over the first 5 years of life. Atypically high level can be predicted from mother and child characteristics present before 6 months of age. Preventive interventions should be experimented with at risk infants and parents.     

Smoking prevention counseling practices of Montreal general practitioners

BACKGROUND: Primary care physicians are potentially important sources of interventions aimed at preventing youth smoking. Yet recent surveys suggest that physician smoking prevention practices are less than optimal. OBJECTIVES: To document prevention counseling practices and to identify correlates of these activities in a random sample of general practitioners in Montreal, Quebec. METHODS: A cross-sectional mail survey. RESULTS: Of 440 eligible general practitioners (GPs), 337 (77%) completed the questionnaire. General practitioners were more likely to ascertain the smoking status of adolescents (70.9%) than preadolescents (35.7%). Although about half of the GPs offered advice to prevent smoking onset in young adults (48.6%) and adolescents (48.3%), fewer did so for preadolescents (34.4%); only 12.1% advised parents to discuss smoking onset with their children. Correlates of ascertaining smoking status included female sex (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.07-3.41), lower proportion of walk-in patients (OR, 2.73; 95% CI, 1.31-5.80), awareness of the "stage of behavior change" model (OR, 2.17; 95% CI, 1.18-4.04), and higher self-efficacy (OR, 4.12, 95% CI, 2.00-8.69). Correlates of provision of prevention advice included more hours spent in direct patient care (OR, 1.93; 95% CI, 1.13-3.34), favorable beliefs and attitudes (OR, 1.73; 95% CI, 1.06-2.83), and higher self-efficacy (OR, 4.32; 95% CI, 2.25-8.44). CONCLUSIONS: Our results point to the need for renewed efforts to enhance preventive efforts in primary care settings. Intervention programs for GPs should emphasize overcoming unfavorable beliefs and attitudes and low self-efficacy. Future research should evaluate the effect of brief prevention counseling adapted to increasingly busy practices.     

Adenoviral Expression of a Bispecific VHH-Based Neutralizing Agent That Targets Protective Antigen Provides Prophylactic Protection from Anthrax in Mice

Bacillus anthracis, the causative agent of anthrax, secretes three polypeptides, which form the bipartite lethal and edema toxins (LT and ET, respectively). The common component in these toxins, protective antigen (PA), is responsible for binding to cellular receptors and translocating the lethal factor (LF) and edema factor (EF) enzymatic moieties to the cytosol. Antibodies against PA protect against anthrax. We previously isolated toxin-neutralizing variable domains of camelid heavy-chain-only antibodies (VHHs) and demonstrated their in vivo efficacy. In this work, gene therapy with an adenoviral (Ad) vector (Ad/VNA2-PA) (VNA, VHH-based neutralizing agents) promoting the expression of a bispecific VHH-based neutralizing agent (VNA2-PA), consisting of two linked VHHs targeting different PA-neutralizing epitopes, was tested in two inbred mouse strains, BALB/cJ and C57BL/6J, and found to protect mice against anthrax toxin challenge and anthrax spore infection. Two weeks after a single treatment with Ad/VNA2-PA, serum VNA2-PA levels remained above 1 μg/ml, with some as high as 10 mg/ml. The levels were 10- to 100-fold higher and persisted longer in C57BL/6J than in BALB/cJ mice. Mice were challenged with a lethal dose of LT or spores at various times after Ad/VNA2-PA administration. The majority of BALB/cJ mice having serum VNA2-PA levels of >0.1 μg/ml survived LT challenge, and 9 of 10 C57BL/6J mice with serum levels of >1 μg/ml survived spore challenge. Our findings demonstrate the potential for genetic delivery of VNAs as an effective method for providing prophylactic protection from anthrax. We also extend prior findings of mouse strain-based differences in transgene expression and persistence by adenoviral vectors.     

Psychosocial impact of predictive testing for myotonic dystrophy type 1

In the Saguenay-Lac-Saint-Jean region (Quebec, Canada), a predictive DNA-testing program for myotonic dystrophy type 1 (DM1) has been available as a clinical service since 1988. From 1 to 12 years (median, 5 years) after receiving predictive testing, a total of 308 participants (44 carriers and 264 non-carriers) answered a questionnaire to determine the psychosocial impact of this genetic testing. The main reasons for wanting to be tested were to learn if children are at risk for DM1 or for reproductive decision making (75%) and to relieve the uncertainty for themselves (17%). The majority of participants (96.1%) remembered correctly their test result. At the time of the survey, the perception of the general well-being, the psychological distress (Psychiatric Symptom Index), and the self-esteem (Rosenberg Self-Esteem Scale) were similar in carriers, in non-carriers, and in the reference (Quebec) population. When participants indicated a change in different aspects of their lives following predictive testing, it was perceived as a change for the better by non-carriers and as a change for the worse by carriers. Nevertheless, for a majority of carriers and of non-carriers, the test result did not bring changes in their lives. All respondents believed that predictive testing should be available for the at-risk population and the vast majority of carrier and of non-carriers would recommend the use of predictive testing to their family members. Predictive testing for individuals at-risk of DM1 can be offered safely within a well-organized clinical and genetic counseling program that includes careful pre-test counseling, pre-test clinical assessment, post-test psychological support, and follow-up for those identified as carriers.     

Mutation of the calcium channel gene Cacna1f disrupts calcium signaling, synaptic transmission and cellular organization in mouse retina

Retinal neural transmission represents a key function of the eye. Identifying the molecular components of this vital process is helped by studies of selected human genetic eye disorders. For example, mutations in the calcium channel subunit gene CACNA1F cause incomplete X-linked congenital stationary night blindness (CSNB2 or iCSNB), a human retinal disorder with abnormal electrophysiological response and visual impairments consistent with a retinal neurotransmission defect. To understand the subcellular basis of this retinal disorder, we generated a mouse with a loss-of-function mutation by inserting a self-excising Cre-lox-neo cassette into exon 7 of the murine orthologue, Cacna1f. Electroretinography of the mutant mouse revealed a scotopic a-wave of marginally reduced amplitude compared with the wild-type mouse and absence of the post-receptoral b-wave and oscillatory potentials. Cone ERG responses together with visual evoked potentials and multi-unit activity in the superior colliculus were also absent. Calcium imaging in Fluo-4 loaded retinal slices depolarized with KCl showed 90% less peak signal in the photoreceptor synapses of the Cacna1f mutant than in wild-type mice. The absence of post-receptoral ERG responses and the diminished photoreceptor calcium signals are consistent with a loss of Ca((2+)) channel function in photoreceptors. Immunocytochemistry showed no detectable Ca(v)1.4 protein in the outer plexiform layer of Cacna1f-mutant mice, profound loss of photoreceptor synapses, and abnormal dendritic sprouting of second-order neurons in the photoreceptor layer. Together, these findings in the Cacna1f-mutant mouse reveal that the Ca(v)1.4 calcium channel is vital for the functional assembly and/or maintenance and synaptic functions of photoreceptor ribbon synapses. Moreover, the outcome of this study provides critical clues to the pathophysiology of the human retinal channelopathy of X-linked incomplete CSNB.     

Serum TABM produced during anterior chamber-associated immune deviation passively transfers suppression of delayed-type hypersensitivity to primed mice

Injection of soluble protein antigen into the anterior chamber of the eye of primed mice induces anterior chamber-associated immune deviation (ACAID) which is manifested by suppression of delayed-type hypersensitivity (DTH) to the antigen. Recently, we found that ACAID induced in primed mice also results in a rapid rise in serum of soluble T lymphocyte-derived proteins specific for nominal antigen (TABM). Here, we demonstrate that serum TABM induced in primed mice during ACAID will transfer the suppression of DTH to mice primed to the same antigen. Sera from TNP-BSA-primed mice that received an anterior chamber injection of TNP-BSA, but not BSA alone, suppressed the DTH response to TNP when injected into other TNP-BSA-primed mice. Sera absorbed with Sepharose beads conjugated with either anti-TCR C(alpha), anti-TCR C(beta), anti-TABM or TNP-BSA did not contain TNP-specific TABM and did not transfer suppression of DTH. These results suggest that the antigen-specific, TCR C(alphabeta)+ TABM that appear in serum during ACAID are able to confer on or amplify the capacity of sensitized T cells to suppress DTH. We believe this to be the first demonstration of an in vivo immunologic function that is specifically associated with TABM produced in vivo.