Statin withdrawal and health-related quality of life in a primary cardiovascular prevention cohort

PURPOSE

While some work has been done on Health-Related Quality of Life (HRQoL) in statin users, none has focused specifically on statin-associated muscle symptoms (SAMS) sufferers. The objective was to assess self-reported HRQoL, before and after statin withdrawal, in patients reporting SAMS. We hypothesized that the presence of SAMS associated with decreased self-reported physical and mental well-being.

METHODS

Patients (50 men/28 women [M/W], aged 49 ± 9 years [Mean ± SD]) in primary cardiovascular prevention were recruited into three cohorts: statin users with (SAMS, 29 M/18W) or without symptoms (No SAMS, 10 M/5W) and controls (11 M/5W). The Short Form 36 Health Survey (SF-36) was used to assess HRQoL. All variables were measured before and after 2 months of statin withdrawal, and repeated measures analyses were used to verify withdrawal and group effects as well as their interaction.

RESULTS

SF-36 physical and mental component scores (respectively, PCS and MCS) were lower in the SAMS group compared with other groups (both p < 0.01). Statin withdrawal led to an increase in LDL cholesterol for statin users (+69.0%, p < 0.01) and an improvement in well-being in the SAMS group, other groups showing no change. A time x category interaction (p = 0.02) was seen for PCS and post hoc analyses showed that statin withdrawal improved PCS and MCS (respectively, +12.5% [ES 0.77] and +5.1% [ES 0.27], both p < 0.05) in the SAMS group.

CONCLUSION

Patients self-reporting SAMS showed improved HRQoL following drug withdrawal, but this was mirrored by a rise in LDL cholesterol. These findings should be considered by clinicians in the evaluation and follow-up of treatment with statins.

Inhibiting nighttime melatonin and boosting cortisol increase patrolling monocytes, phagocytosis, and myelination in a murine model of multiple sclerosis

Conflicting results on melatonin synthesis in multiple sclerosis (MS) have been reported due to variabilities in patient lifestyles, which are not considered when supplementing melatonin. Since melatonin acts through its receptors, we identified melatonin receptors in oligodendrocytes (OLs) in the corpus callosum, where demyelination occurs; the subventricular zone, where neural stem/progenitor cells (NSPCs) are located; and the choroid plexus, which functions as a blood-cerebrospinal fluid barrier. Moreover, using chimeric mice, resident macrophages were found to express melatonin receptors, whereas bone marrow-derived macrophages lost this expression in the demyelinated brain. Next, we showed that cuprizone-fed mice, which is an MS model, tended to have increased melatonin levels. While we used different approaches to alter the circadian rhythm of melatonin and cortisol, only the constant light approach increased NSPC proliferation and differentiation to oligodendrocyte precursor cells (OPCs), OPCs maturation to OLs and recruitment to the site of demyelination, the number of patrolling monocytes, and phagocytosis. In contrast, constant darkness and exogenous melatonin exacerbated these events and amplified monocyte infiltration. Therefore, melatonin should not be considered a universal remedy, as is currently claimed. Our data emphasize the importance of monitoring melatonin/cortisol oscillations in each MS patient by considering diet and lifestyle to avoid melatonin overdose.

Case Report: Two Families With HPDL Related Neurodegeneration

There are recent reports of associations of variants in the HPDL gene with a hereditary neurological disease that presents with a wide spectrum of clinical severity, ranging from severe neonatal encephalopathy with no psychomotor development to adolescent-onset uncomplicated spastic paraplegia. Here, we report two probands from unrelated families presenting with severe and intermediate variations of the clinical course. A homozygous variant in the HPDL gene was detected in each proband; however, there was no known parental consanguinity. We also highlight reductions in citrate synthase and mitochondrial complex I activity detected in both probands in different tissues, reflecting the previously proposed mitochondrial nature of disease pathogenesis associated with HPDL mutations. Further, we speculate on the functional consequences of the detected variants, although the function and substrate of the HPDL enzyme are currently unknown.

ABHD16A deficiency causes a complicated form of hereditary spastic paraplegia associated with intellectual disability and cerebral anomalies

ABHD16A (abhydrolase domain-containing protein 16A, phospholipase) encodes the major phosphatidylserine (PS) lipase in the brain. PS lipase synthesizes lysophosphatidylserine, an important signaling lipid that functions in the mammalian central nervous system. ABHD16A has not yet been associated with a human disease. In this report, we present a cohort of 11 affected individuals from six unrelated families with a complicated form of hereditary spastic paraplegia (HSP) who carry bi-allelic deleterious variants in ABHD16A. Affected individuals present with a similar phenotype consisting of global developmental delay/intellectual disability, progressive spasticity affecting the upper and lower limbs, and corpus callosum and white matter anomalies. Immunoblot analysis on extracts from fibroblasts from four affected individuals demonstrated little to no ABHD16A protein levels compared to controls. Our findings add ABHD16A to the growing list of lipid genes in which dysregulation can cause complicated forms of HSP and begin to describe the molecular etiology of this condition.

Selective Immunomodulatory and Neuroprotective Effects of a NOD2 Receptor Agonist on Mouse Models of Multiple Sclerosis

The significance of monocytes has been demonstrated in multiple sclerosis (MS). One of the therapeutic challenges is developing medications that induce mild immunomodulation that is solely targeting specific monocyte subsets without affecting microglia. Muramyl dipeptide (MDP) activates the NOD2 receptor, and systemic MDP administrations convert Ly6Chigh into Ly6Clow monocytes. Here, we report selective immunomodulatory and therapeutic effects of MDP on cuprizone and experimental autoimmune encephalomyelitis (EAE) mouse models of MS. MDP treatment exerted various therapeutic effects in EAE, including delaying EAE onset and reducing infiltration of leukocytes into the CNS before EAE onset. Of great interest is the robust beneficial effect of the MDP treatment in mice already developing the disease several days after EAE onset. Finally, we found that the NOD2 receptor plays a critical role in MDP-mediated EAE resistance. Our results demonstrate that MDP is beneficial in both early and progressive phases of EAE. Based on these results, and upon comprehensive basic and clinical research, we anticipate developing NOD2 agonist-based medications for MS in the future.

The Intellicage system provides a reproducible and standardized method to assess behavioral changes in cuprizone-induced demyelination mouse model

BACKGROUND

Multiple sclerosis is a neurodegenerative disorder characterized by myelin loss in the brain parenchyma. To mimic the disease, mice are fed a cuprizone-supplemented diet for 5 weeks, which leads to demyelination of white and grey matter regions, with the corpus callosum being the most susceptible to cuprizone intoxication. Although this model is highly exploited, classical behavioural tests showed inconsistent results.

OBJECTIVE

In our study, we aimed to use the automated system Intellicage to phenotype the behaviour of cuprizone-fed mice.

METHODS

Mice were continuously monitored during the 5 weeks of intoxication in their home cages, with minimal interference from the experimenter. Mice were assessed for spontaneous activity, fine movements, and impulsivity.

RESULTS

Consistently, cuprizone-fed mice showed reduced activity and impulsivity throughout the test period. These behavioral results were confirmed by repeating the battery of behavioral tests in a second cohort of cuprizone-fed mice. Our results suggest that the behavioural phenotyping of cuprizone-fed mice using Intellicage is reproducible and sensitive enough to detect changes normally missed in standard behavioral test batteries.

CONCLUSION

Using a reproducible and standardized method to assess behavioral changes in mice intoxicated with cuprizone is crucial to better understand the disease as well as the functional outcome of treatments.

Muramyl dipeptide-mediated immunomodulation on monocyte subsets exerts therapeutic effects in a mouse model of Alzheimer's disease

Background

Muramyl dipeptide (MDP) is a component derived from minimal peptidoglycan motif from bacteria, and it is a ligand for the NOD2 receptor. Peripheral administration of MDP converts Ly6C^high into Ly6C^low monocytes. Previously, we have shown that Ly6C^low monocytes play crucial roles in the pathology of a mouse model of Alzheimer’s disease (AD). However, medications with mild immunomodulatory effects that solely target specific monocyte subsets, without triggering microglial activation, are rare.

Methods

Three months old APP_swe/PS1 transgenic male mice and age-matched C57BL/6 J mice were used for high frequency (2 times/week) over 6 months and low frequency (once a week) over 3 months of intraperitoneally MDP (10 mg/kg) administrations. Flow cytometry analysis of monocyte subsets in blood, and behavioral and postmortem analyses were performed.

Results

Memory tests showed mild to a strong improvement in memory function, increased expression levels of postsynaptic density protein 95 (PSD95), and low-density lipoprotein receptor-related protein 1 (LRP1), which are involved in synaptic plasticity and amyloid-beta (Aβ) elimination, respectively. In addition, we found monocyte chemoattractant protein-1(MCP-1) levels significantly increased, whereas intercellular adhesion molecule-1(ICAM-1) significantly decreased, and microglial marker (Iba1) did not change in the treatment group compared to the control. In parallel, we discovered elevated cyclooxygenase-2 (COX2) expression levels in the treated group, which might be a positive factor for synaptic activity.

Conclusions

Our results demonstrate that MDP is beneficial in both the early phase and, to some extent, later phases of the pathology in the mouse model of AD. These data open the way for potential MDP-based medications for AD.

Role of Macrophage Colony-Stimulating Factor Receptor on the Proliferation and Survival of Microglia Following Systemic Nerve and Cuprizone-Induced Injuries

Microglia are the innate immune cells of the CNS and their proliferation, activation, and survival have previously been shown to be highly dependent on macrophage colony-stimulating factor receptor (CSF1R). Here we investigated the impact of the receptor in such processes using two different models of nerve injuries, namely hypoglossal axotomy and cuprizone-induced demyelination. Both models are associated with a robust microgliosis. The role of CSF1R was investigated using the gene deletion Cre/Lox system, which allows the conditional knock-out following tamoxifen administration. We found that after 5 weeks of cuprizone diet that CSF1R suppression caused a significant impairment of microglia function. A reduced microgliosis was detected in the corpus collosum of CSF1R knock-out mice compared to controls. In contrast to cuprizone model, the overall number of Iba1 cells was unchanged at all the times evaluated following hypoglossal axotomy in WT and cKO conditions. After nerve lesion, a tremendous proliferation was noticed in the ipsilateral hypoglossal nucleus to a similar level in both knock-out and wild-type groups. We also observed infiltration of bone-marrow derived cells specifically in CSF1R-deficient mice, these cells tend to compensate the CSF1R signaling pathway suppression in resident microglia. Taking together our results suggest a different role of CSF1R in microglia depending on the model. In the pathologic context of cuprizone-induced demyelination CSF1R signaling pathway is essential to trigger proliferation and survival of microglia, while this is not the case in a model of systemic nerve injury. M-CSF/CSF1R is consequently not the unique system involved in microgliosis following nerve damages.

Chondroitin sulfate proteoglycans as novel drivers of leucocyte infiltration in multiple sclerosis

Multiple sclerosis presents with profound changes in the network of molecules involved in maintaining central nervous system architecture, the extracellular matrix. The extracellular matrix components, particularly the chondroitin sulfate proteoglycans, have functions beyond structural support including their potential interaction with, and regulation of, inflammatory molecules. To investigate the roles of chondroitin sulfate proteoglycans in multiple sclerosis, we used the experimental autoimmune encephalomyelitis model in a time course study. We found that the 4-sulfated glycosaminoglycan side chains of chondroitin sulfate proteoglycans, and the core protein of a particular family member, versican V1, were upregulated in the spinal cord of mice at peak clinical severity, correspondent with areas of inflammation. Versican V1 expression in the spinal cord rose progressively over the course of experimental autoimmune encephalomyelitis. A particular structure in the spinal cord and cerebellum that presented with intense upregulation of chondroitin sulfate proteoglycans is the leucocyte-containing perivascular cuff, an important portal of entry of immune cells into the central nervous system parenchyma. In these inflammatory perivascular cuffs, versican V1 and the glycosaminoglycan side chains of chondroitin sulfate proteoglycans were observed by immunohistochemistry within and in proximity to lymphocytes and macrophages as they migrated across the basement membrane into the central nervous system. Expression of versican V1 transcript was also documented in infiltrating CD45+ leucocytes and F4/80+ macrophages by in situ hybridization. To test the hypothesis that the chondroitin sulfate proteoglycans regulate leucocyte mobility, we used macrophages in tissue culture studies. Chondroitin sulfate proteoglycans significantly upregulated pro-inflammatory cytokines and chemokines in macrophages. Strikingly, and more potently than the toll-like receptor-4 ligand lipopolysaccharide, chondroitin sulfate proteoglycans increased the levels of several members of the matrix metalloproteinase family, which are implicated in the capacity of leucocytes to cross barriers. In support, the migratory capacity of macrophages in vitro in a Boyden chamber transwell assay was enhanced by chondroitin sulfate proteoglycans. Finally, using brain specimens from four subjects with multiple sclerosis with active lesions, we found chondroitin sulfate proteoglycans to be associated with leucocytes in inflammatory perivascular cuffs in all four patients. We conclude that the accumulation of chondroitin sulfate proteoglycans in the perivascular cuff in multiple sclerosis and experimental autoimmune encephalomyelitis boosts the activity and migration of leucocytes across the glia limitans into the central nervous system parenchyma. Thus, chondroitin sulfate proteoglycans represent a new class of molecules to overcome in order to reduce the inflammatory cascades and clinical severity of multiple sclerosis.

Cochlear implantation in patients with chronic otitis media and radical mastoidectomy: A single-stage procedure

BACKGROUND

We conducted a retrospective case review of patients with mastoid cavity and active or inactive chronic otitis media (COM) who underwent cochlear implantation and ear obliteration in a single-stage procedure. The objectives of this review are to assess the rates of complications and postoperative infections and to evaluate post-implantation audiologic performance.

MATERIALS AND METHODS

All patients with COM and mastoid cavity, associated or not with active disease, who undergo cochlear implantation and obliteration of the ear as a single-stage procedure from November 2004 to April 2013, were included in the review. All the complications were recorded. Open-set sentence scores were used to evaluate the audiologic gain after implantation.

RESULTS

Twenty-seven patients were included in our review: Ten with active COM and seventeen with inactive COM. Overall, nine patients (9/27) presented post-operative complications (7/9 were minor): three were amongst active COM patients (30%) as compared to six amongst inactive COM patients (35%), which included the two major complications. A mean gain of 55.9% on open-set sentence scores was obtained after cochlear implantation.

DISCUSSION

We found that complications rate of the one-stage cochlear implantation was higher in patients with COM than in global implant population, but most complications were minors and there was no statistical difference between active and inactive COM. In addition, these patients had audiologic scores similar to those found in patients with normal temporal bone anatomy.

CONCLUSION

Cochlear implantation performed as a one-stage procedure could be considered as an option of treatment to avoid staging in patients with active and inactive COM. Although these patients need a regular follow-up, they present good post-implantation audiometric scores.

Assessment of the prevalence of the 985A>G MCAD mutation in the French-Canadian population using allele-specific PCR

Inherited deficiency of medium-chain acyl-CoA dehydrogenase (MCAD) is a severe, sometimes fatal disorder. A single mutation in the MCAD gene, 985A>G, is involved in approximately 90% of cases. To evaluate the relevance of implementing a systematic population-based screening program in the province of Quebec using a biochemical test, we measured the prevalence of this mutation in a set of anonymous newborn samples from the Quebec City area, a region where the majority of its inhabitants are French-Canadians. An allele-specific polymerase chain reaction assay was designed and used to detect the mutation in 7143 DNA samples obtained from consecutive anonymous newborns. Pools of eight DNA samples were genotyped in parallel for the same mutation to validate this pooling strategy. The allelic frequency of the MCAD 985A>G mutation was found to be 0.71% and the carrier frequency 1:71 (95% confidence interval 1:55 to 1:98). This estimate predicts a homozygous frequency of 1:19,837. Ninety-nine heterozygous carriers and one homozygous individual were identified out of 7143 samples. There was 100% concordance between the individual and pooled analyses, and the pooling strategy reduced the total genotyping costs by approximately 70%. The carrier frequency estimated for this population is similar to other northwestern European populations and would support implementation of systematic newborn screening (such as tandem mass spectrometry screening) for this disease. Pooling DNA samples followed by genotyping appears to be cost-effective for estimating prevalence of rare mutations.

Hereditary hemochromatosis screening: effect of mutation penetrance and prevalence on cost-effectiveness of testing algorithms

Screening for hereditary hemochromatosis, although largely discussed, is not yet implemented in clinical practice. We evaluated the cost-effectiveness of 165 hemochromatosis population-screening algorithms involving two or three of several screening tests by developing a computer program that simulates all possible screening scenarios. Input data comprised government estimates of health services data and costs and a virtual population with user-defined demographic characteristics (including variable HFE mutation frequencies and penetrance values). We show that when C282Y homozygote prevalence is set at 3:1000, population screening appears cost-effective when penetrance of the biochemical phenotype is >0.70. When only hepatocellular carcinoma and cirrhosis are considered as the cost-driving complications, population-based screening is not significantly more cost-efficient than no screening, but life expectancy of individuals identified with hereditary hemochromatosis and treated is still improved by 7 years. Among the 165 screening algorithms tested in 91 different virtual populations of one million individuals, biochemical tests usually perform better as the initial test than genetic testing. Indeed, the genetic testing is most cost-effective as the final confirmatory test. Finally, for most combinations of prevalence and penetrance of HFE, one screening algorithm--unbound iron-binding capacity + transferrin saturation--appeared robust enough to be always within the top 5 most cost-effective strategies.

Leisure physical activity is associated with quantitative ultrasound measurements independently of bone mineral density in postmenopausal women

The purpose of this study was to assess the magnitude of the relationship between leisure physical activity and bone status as measured either by an Achilles ultrasound bone densitometer (QUS) or dual-energy X-ray absorptiometry (DXA) in postmenopausal women. We studied 1162 French Canadian postmenopausal women, aged 33-84 years (mean age 58 years), for QUS parameters [broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI)] measured at the right calcaneus, and bone mineral density (BMD) measured at the lumbar spine and femoral neck. Multivariate regression analyses revealed that leisure physical activity level was an independent predictor of the heel QUS parameters and of femoral neck BMD. No such association was observed for BMD of the lumbar spine. Heel QUS parameters (BUA, SOS, SI) and femoral neck BMD adjusted for interfering covariables showed a statistically significant difference between sedentary (less than three sessions/month) and active women (three or more sessions/week) (P < or = 0.001). Furthermore, after adjusting each heel QUS parameters for the mean lumbar spine BMD value, the association observed between leisure physical activity and QUS remained significant. These results suggest that regular leisure physical activity could influence QUS parameters, independently of BMD, and that quantitative ultrasound could be a suitable outcome measure in exercise studies in postmenopausal women.

Circulating cell wall components derived from gram-negative, not gram-positive, bacteria cause a profound induction of the gene-encoding Toll-like receptor 2 in the CNS

The recent characterization of human homologs of Toll may be the missing link for the transduction events leading to nuclear factor-kappaB (NF-kappaB) activity and proinflammatory gene transcription during innate immune response. Mammalian cells may express as many as 10 distinct Toll-like receptors (TLRs), although TLR2 is a key receptor for recognizing cell wall components of Gram-positive bacteria. The present study investigated the effects of circulating bacterial cell wall components on the expression of the gene-encoding TLR2 across the mouse brain. Surprisingly, while Gram-negative components caused a robust increase in TLR2 transcription within the cerebral tissue, peptidoglycan (PGN) and lipoteichoic acid (LTA), either alone or combined, failed to modulate the receptor transcript. Indeed, the mRNA levels for TLR2 in the choroid plexus and few other regions of the brain remained similar between vehicle-, LTA-, PGN-, and LTA/PGN-administered mice at all the times evaluated (i.e. 30 min to 24 h post-intraperitoneal injection). This contrasts with the profound de novo expression of TLR2 following a single systemic injection of the lipopolysaccharide (LPS). The signal was first detected in regions devoid of blood-brain barrier and few blood vessels and microcapillaries. A second wave of TLR2 expression was also detected from these structures to their surrounding parenchymal cells that stained for a microglial marker iba1. The rapid induction of IkappaBalpha (index of NF-kappaB activity) and up-regulation of the adaptor protein MyD88 suggest that LPS-induced TLR2 transcription may be dependent on the NF-kappaB pathway. These data provide the evidence that TLR2 is not only present in the brain, but its encoding gene is regulated by cell wall components derived from Gram-negative, not Gram-positive, bacteria. The robust wave of TLR2-expressing microglial cells may have a determinant impact on the innate immune response that occurs in the brain during systemic infection by Gram-negative, not Gram-positive, bacteria.

Short polyglutamine tracts in the androgen receptor are protective against breast cancer in the general population

We studied the association of breast cancer with the polymorphic polyglutamine repeat of the androgen receptor (AR) in 255 incident cases of breast cancer and 461 matched controls from the Quebec City metropolitan area. Women for whom the sum of both of the AR (CAG)n-repeats alleles is 39 or less (short-allele AR genotypes) have one-half the risk of breast cancer compared with women for whom the sum of AR (CAG)n-repeats is 40 or more [odds ratio (OR), 0.5; 95% confidence interval (CI), 0.3-0.83; P = 0.007]. This association is stronger in postmenopausal women (180 cases, 297 controls; OR, 0.36; 95% CI, 0.19-0.7; P = 0.003). We also observed an interaction between the type of menopause (natural versus surgical) and the AR genotype on breast cancer risk. Alternately, when subjects were grouped according to their (CAG)n-repeat genotype [homozygous for short alleles (CAG)n < or = 20; other genotypes ("long allele")], results were similar (OR. 0.5; 95% CI, 0.27-0.82; P = 0.007). Thus, women with short-alleles AR genotypes appear to be protected against breast cancer. Short-alleles AR genotypes were observed in 16% of the general population as represented by the control group. Short polyglutamine repeats in the AR protein have been reported to be associated with an increase in the capacity of the receptor to activate transcription of reporter genes in vitro. Furthermore, androgens have been previously shown to inhibit in vitro the growth of breast cancer cell lines. This suggests that differences in the number of polyglutamines in the AR protein may influence individual risk of breast cancer, especially in postmenopausal women, and that this apparent protection could be the consequence of an increased response/sensitivity to androgens.

Regulation of the gene encoding the monocyte chemoattractant protein 1 (MCP-1) in the mouse and rat brain in response to circulating LPS and proinflammatory cytokines

Accumulating evidence supports the existence of an innate immune response in the brain during systemic inflammation that is associated with a robust induction of proinflammatory cytokines and chemokines by specific cells of the central nervous system. The present study investigated the genetic regulation and fine cellular distribution of the monocyte chemoattractant protein-1 (MCP-1) in the brain of mice and rats in response to systemic immune insults. MCP-1 belongs to a superfamily of chemokines that have a leading role in the early chemotaxic events during inflammation. In situ hybridization histochemistry failed to detect constitutive expression of the chemokine transcript in the cerebral tissue except for the area postrema (AP) that exhibited a low signal under basal conditions. This contrasts with the strong and transient induction of the mRNA encoding MCP-1 following a single systemic bolus of lipopolysaccharide (LPS), recombinant interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha). These stimuli rapidly triggered (30 to 90 minutes) MCP-1 transcription in all the circumventricular organs (CVOs), the choroid plexus (chp), the leptomeninges, and along the cerebral blood vessels. The time-related induction and intensity of the signal differed among the challenges, route of administration and species, but MCP-1-expressing cells were always found in vascular-associated structures and those devoid of blood-brain barrier. At later times, few isolated microglia across the brain parenchyma depicted positive signal for MCP-1 mRNA. A dual-labeling procedure also provided convincing anatomical evidence that endothelial cells of the microvasculature and a few myeloid cells of the CVOs and chp were positive for the transcript during endotoxemia. This gene is under a sophisticated transcriptional regulation, as the hybridization signal returned to undetectable levels 12 to 24 hours after all the treatments in both species. Of interest are the data that only ligands that triggered nuclear factor kappa B (NF-kappa B) signaling had the ability to increase MCP-1 gene expression, because high doses of IL-6 remained without effects. These data provide the anatomical evidence that MCP-1 is expressed within specific populations of cells in response to systemic inflammatory molecules that use NF-kappa B as intracellular signaling system. This chemokine may therefore play a critical role in the cerebral innate immune response and contribute to the early chemotaxic events during chronic cerebral inflammation.

[Lack of conviction about vaccination in certain Quebec vaccinators]

A questionnaire was mailed to all vaccinators in Quebec in 1998. The objective of this survey was to document vaccinators' attitudes, knowledge, and practices related to vaccination. Vaccinators generally believe in the security, efficacy and usefulness of vaccines given to young children. However, 41% of nurses do not fully agree with these opinions. More than 94% of pediatricians completely disagree that "certain practices (homeopathy, good eating habits and a healthy lifestyle) can eliminate the need for vaccination", compared with 85% of general practitioners and only 60% of nurses. Less than 25% of doctors recall children who are late in getting their immunizations; approximately 45% of vaccinators are in complete agreement with simultaneous injections of two vaccines; many circumstances are incorrectly seen as contra indications for vaccination. Public health authorities should target systematic interventions towards vaccinators to improve this situation and to increase nurses' conviction regarding the benefits of vaccination.

[Lack of conviction about vaccination in certain Quebec vaccinators]

A questionnaire was mailed to all vaccinators in Quebec in 1998. The objective of this survey was to document vaccinators' attitudes, knowledge, and practices related to vaccination. Vaccinators generally believe in the security, efficacy and usefulness of vaccines given to young children. However, 41% of nurses do not fully agree with these opinions. More than 94% of pediatricians completely disagree that "certain practices (homeopathy, good eating habits and a healthy lifestyle) can eliminate the need for vaccination", compared with 85% of general practitioners and only 60% of nurses. Less than 25% of doctors recall children who are late in getting their immunizations; approximately 45% of vaccinators are in complete agreement with simultaneous injections of two vaccines; many circumstances are incorrectly seen as contra indications for vaccination. Public health authorities should target systematic interventions towards vaccinators to improve this situation and to increase nurses' conviction regarding the benefits of vaccination.

Toll-like receptor 4: the missing link of the cerebral innate immune response triggered by circulating gram-negative bacterial cell wall components

The recent characterization of human homologues of Toll may be the missing link for the transduction events leading to NF-kappaB activity and proinflammatory gene transcription during innate immune response. Indeed, CD14 is not thought to participate directly in the cell signaling, but rather one or more of the mammalian Toll-like receptors (TLRs) acts in concert with the lipopolysaccharide (LPS) receptor to discriminate between microbial pathogens or their products and initiate transmembrane signaling. Mammalian cells may express as many as 10 distinct TLRs, although the importance of TLR4 in response to gram-negative bacteria and LPS is now supported by the fact that TLR4-mutated mice are LPS resistant. We investigated the expression of TLR4 across the rat brain under basal conditions and in response to systemic LPS and IL-1beta injection. We first cloned the rat TLR4 cDNA via RNA isolation and polymerase chain reaction (PCR) amplification with a proofreading polymerase. Total RNA was isolated from the rat liver tissue using Tri-Reagent and reverse transcribed into cDNA using Superscript II reverse transcriptase and an oligonucleotide primer with a degenerate 3' end of sequence 5'-T12(GAC)N-3'. Positive hybridization signal was found in the leptomeninges, choroid plexus (chp), subfornical organ, organum vasculosum of the lamina terminalis, median eminence, and area postrema. Scattered small cells also displayed a convincing hybridization signal within the brain parenchyma. Few well-defined nuclei exhibited positive TLR4 transcript: the supramamillary nucleus, cochlear nucleus, and the lateral reticular nucleus. The circumventricular organs, the leptomeninges, and chp also exhibited constitutive expression of the LPS receptor mCD14. In contrast to the strong up-regulation of the gene encoding mCD14 during endotoxemia, neither LPS nor IL-1beta caused a convincing increase in the TLR4 mRNA levels across the CNS. A down-regulation of the gene encoding TLR4 was found in the cerebral tissue of immune-challenged animals. The constitutive expression of both mCD14 and TLR4 may explain the innate immune response in the brain, which originates from the structures devoid of blood-brain barrier in presence of circulating LPS.

Comparative immunogenicity under field conditions of two recombinant hepatitis B vaccines in 8-10-year-old children

The immunogenicity of two hepatitis B vaccines was compared in 8-10-year-old children immunized in a school program. One year apart, 1129 children received Engerix-B 10 microg vaccine (EB), and 1126 received Recombivax-HB 2.5 microg (RB), following the 0, 1, 6 schedule. Blood samples were collected one month after the third dose. Anti-Hbs were measured by commercial radioimmunoassay. In the EB group, 99.1% of the children seroconverted (>/=2 IU/l) compared to 99.7% in the RHB group (p=0.09). The seroprotection rate (>/=10 IU/l) was similar for both groups: 98.9% in the EB group and 99.2% in the RB group (p=0.66). However, GMCs of anti-HBs were higher in children given EB compared to those given RB (7307 vs. 3800 mIU/ml, p<0.0001). This study showed that both vaccines were highly immunogenic, in the course of a regular field immunization program. However, the difference observed in the antibody levels attained according to the vaccine may play a role in the long-term protection of these children.

How the blood talks to the brain parenchyma and the paraventricular nucleus of the hypothalamus during systemic inflammatory and infectious stimuli

There are exciting new developments regarding the molecular mechanisms involved in the influence of circulating proinflammatory molecules within cells of the blood-brain barrier (BBB) during systemic immune challenges. These molecules, when present in the circulation, have the ability to trigger a series of events in cascade, leading to either the mitogen-activated protein (MAP) kinases/nuclear factor kappa B (NF-kappaB) or the janus kinase (JAK)/signal transducer and activator of transcription (STAT) transduction pathways in vascular-associated cells of the central nervous system (CNS). The brain blood vessels exhibit both constitutive and induced expression of receptors for different proinflammatory ligands that have the ability to stimulate these signaling molecules. Depending on the challenges and the cytokines involved, the transduction signal(s) solicited in cells of the BBB may orient the neuronal activity in a very specific manner in activating the transcription and production of soluble factors, such as prostaglandins (PGs). It is interesting to note that cytokines as well as systemic localized inflammation stimulate the cells of the BBB in a nonselective manner (i.e., within both large blood vessels and small capillaries across the brain). This nonselectivity raises several questions with regard to the localized neuronal activation induced by different experimental models of inflammation and cytokines. It is possible that the selectivity of the neuronal response is a consequence of the fine interaction between nonparenchymal synthesis of soluble mediators and expression of specific receptors for these ligands within parenchymal elements of different brain nuclei. This review will present the recent developments on this concept and the mechanisms that take place in cells of the BBB, which lead to the neuronal circuits involved in restoring the body's homeostasis during systemic immunogenic challenges. The induction of fever, the hypothalamic-pituitary adrenal (HPA) axis, and other autonomic functions are among the physiological outcomes necessary for the protection of the mammalian organism in the presence of foreign material.

An essential role of interleukin-1beta in mediating NF-kappaB activity and COX-2 transcription in cells of the blood-brain barrier in response to a systemic and localized inflammation but not during endotoxemia

When released into the bloodstream, proinflammatory cytokines have the ability to trigger the transcription of different genes in cells of the blood-brain barrier (BBB), including members of the nuclear factor kappa B (NF-kappaB) family and cyclooxygenase-2 (COX-2), the limiting enzyme for the formation of prostaglandins (PGs). The present study investigated the possibility that interleukin-1beta (IL-1beta) plays an essential role in these events during a systemic inflammatory response. Both wild-type and IL-1beta-deficient mice were killed at different times after two different immunogenic stimuli, i.e., intraperitoneal lipopolysaccharide (LPS) injection and intramuscular turpentine injection, used here as a model of systemic localized inflammatory insult. The inhibitory factor kappaBalpha (IkappaBalpha, index of NF-kappaB activity) and COX-2 transcripts were detected throughout the brain by means of in situ hybridization. Systemic LPS injection caused a strong and rapid expression of IkappaBalpha in endothelial cells lining the BBB of large and small blood vessels and thereafter within parenchymal microglia across the brain. This treatment also provoked a transient expression of COX-2 along cells of the vascular system, and the expression pattern and intensity of the signal for both transcripts were essentially the same in wild-type and IL-1beta-deficient animals. In contrast, the induction of these genes that was quite selective to the cells of the BBB in response to intramuscularly turpentine insult was completely abolished in IL-1beta-deficient mice. Indeed, a late and prolonged expression of IkappaBalpha and COX-2 mRNAs was found along the cerebral blood vessels in response to the sterile and localized inflammation in wild-type mice, whereas such induction was absent in the brain of IL-1beta-deficient animals. These results indicate that IL-1beta has an obligatory role in the activation of NF-kappaB molecules and PGs within endothelial cells of the BBB in an experimental model of intramuscularly turpentine-induced inflammation but not during endotoxemia.

Effects of systemic immunogenic insults and circulating proinflammatory cytokines on the transcription of the inhibitory factor kappaB alpha within specific cellular populations of the rat brain

Expression of the inhibitory factor kappaB alpha (IkappaB alpha) reflects the activity of nuclear factor kappaB(NF-kappaB) and is a powerful tool to investigate the regulation of the transcription factor within the CNS. IkappaB alpha mRNA was evaluated in the rat brain by means of in situ hybridization following different immunogenic stimuli; i.e., intraperitoneal (i.p.) and intravenous (i.v.) lipopolysaccharide (LPS), i.v. recombinant rat interleukin (IL) 1beta, IL-6, or tumor necrosis factor-alpha (TNF-alpha), and intramuscular (i.m.) turpentine injection, used here as a model of systemic localized inflammatory insult. Systemic LPS, IL-1beta, and TNF-alpha caused a rapid and transient transcriptional activation of IkappaB alpha along the blood vessels of the entire brain; the signal was very intense 30-60 min after the i.v. injections and returned to undetectable levels from 2 to 12 h depending on the challenge. Double-labeling procedure provided the anatomical evidence that IkappaB alpha-expressing cells within the microvasculature were essentially of the endothelial type, as they were immunoreactive to the von Willebrand factor. Scattered small cells were also found across the brain of LPS-, IL-1beta-, and TNF-alpha-injected rats at time 1-3 h, and microglial (OX-42)-immunoreactive cells were positive for the transcript. Such expression within parenchymal microglia was nevertheless not observed in the brain following a localized and sterile inflammatory insult. Indeed, i.m. turpentine administration stimulated IkappaB alpha transcription quite uniquely within the endothelium of the brain capillaries, an effect that paralleled the swelling of the injection site and lasted up to 24 h after the aggression. In contrast to these immunogenic challenges, i.v. IL-6 injection failed to activate the gene encoding IkappaB alpha in the rat brain. These results indicate that NF-kappaB may play a crucial role in specific cellular populations of the CNS to trigger transcription of immune-related genes and that IkappaB alpha resynthesis may act as a dynamic intracellular inhibitory feedback to avoid exaggeration of the response. It is possible that IkappaB alpha expression in cells of the blood-brain barrier is a general mechanism that takes place during systemic inflammation, whereas the participation of NF-kappaB-related molecules within parenchymal cells of the CNS is solicited during more severe conditions such as blood sepsis and endotoxemia.

Reduced corticotropin-releasing factor and enhanced vasopressin gene expression in brains of mice with autoimmunity-induced behavioral dysfunction

The spontaneous development of autoimmune disease in MRL-lpr mice induces behavioral and endocrine changes that resemble effects of chronic stressors. To further examine the correspondence between autoimmune disease and chronic stress, we asked whether the brains of autoimmune mice show a shift in the corticotropin-releasing factor (CRF) to vasopressin (AVP) ratio. Using in situ hybridization histochemistry with 35S-labelled mouse riboprobes, the levels of mRNA transcripts encoding CRF and AVP were compared between autoimmune MRL-lpr and control MRL +/+ brains. CRF transcript levels were lower in the hypothalamic paraventricular nucleus and in the central nucleus of the amygdala in MRL-lpr mice. AVP transcript levels were higher in the paraventricular and the supraoptic nuclei in MRL-lpr mice compared to controls. CRF mRNA levels were inversely related to performance in stress-sensitive tasks and to measures of autoimmunity. As found previously for behavioral performance, immunosuppressive treatment with cyclophosphamide abolished the group difference in neuropeptide gene expression. These results indicate that an autoimmune disease process is necessary for the shift in the brain CRF:AVP ratio. Furthermore, they support the parallel between chronic stress and chronic autoimmunity/inflammation, and suggest common central mechanisms relevant to endocrine function and behavior.

Effect of family responsibilities and job strain on ambulatory blood pressure among white-collar women

OBJECTIVE

This study was conducted to determine whether large family responsibilities and their combination with high job strain were associated with an increase in ambulatory blood pressure (BP) among white-collar women.

METHODS

A cross-sectional study was conducted in a stratified random sample of 199 white-collar women with or without children who were employed full time in jobs involving high or low strain. These women were selected from a population of 3183 women of all ages, employed in eight organizations in Quebec City, Canada. Subjects wore an ambulatory BP monitor for 24 hours during a working day. Mean BPs were calculated. Different measures of family responsibilities were used, based on the number of children and their ages, and domestic work. Job strain was measured using the Job Content Questionnaire recommended by Karasek.

RESULTS

Family responsibility measures were significantly related to diurnal BP among women holding a university degree (N=69). Indeed, women having large family responsibilities had increases in systolic and diastolic BPs of 2.7 to 5.7/1.8 to 4.0 mm Hg (p< or =.05). Among women holding a university degree, increases in diurnal systolic and diastolic BPs reached 8.1 to 10.9/5.5 to 7.1 mm Hg (p< or =.01) among women having both large family responsibilities and high job strain. These results were independent of confounders. There was no significant association among women without a university degree (N=130).

CONCLUSIONS

Large family responsibilities were associated with significant increases in diurnal systolic and diastolic BPs among white-collar women holding a university degree. In these women, the combined exposure of large family responsibilities and high job strain tended to have a greater effect on BP than the exposure to only one of these factors.

Involvement of serotonergic pathways in mediating the neuronal activity and genetic transcription of neuroendocrine corticotropin-releasing factor in the brain of systemically endotoxin-challenged rats

The present study investigated the effect of serotonin depletion on the neuronal activity and transcription of corticotropin-releasing factor in the rat brain during the acute-phase response. Conscious male rats received an intraperitoneal (i.p.) injection with the immune activator lipopolysaccaride (25 microg/100 g body wt) after being treated for three consecutive days with para-chlorophenylalanine (30mg/100 g/day). This irreversible inhibitor of tryptophane-5-hydroxylase decreased hypothalamic serotonin levels by 96%. One, 3 and 6 h after a single i.p. injection of lipopolysaccharide or vehicle solution, rats were killed and their brains cut in 30-microm coronal sections. Messenger RNAs encoding c-fos, nerve-growth factor inducible-B gene, corticotropin-releasing factor and the heteronuclear RNA encoding corticotropin-releasing factor primary transcript were assayed by in situ hybridization using 35S-labeled riboprobes, whereas Fos-immunoreactive nuclei were labeled by immunocytochemistry. Lipopolysaccharide induced a wide neuronal activation indicated by the expression of both immediate-early gene transcripts and Fos protein in numerous structures of the brain. The signal for both immediate-early gene transcripts was low to moderate 1 h after lipopolysaccharide administration, maximal at 3 h and decline at 6 h post-injection, whereas at that time, Fos-immunoreactive nuclei were still detected in most of the c-fos messenger RNA-positive structures. Interestingly, the strong and widespread induction of both immediate-early gene transcripts was almost totally inhibited by para-chlorophenylalanine treatment; in the hypothalamic paraventricular nucleus for example, c-fos messenger RNA signal and the number of Fos-immunoreactive positive cells were reduced by 80 and 48%, respectively, in serotonin-depleted rats treated with the bacterial endotoxin. This blunted neuronal response was also associated with an attenuated stimulation of neuroendocrine corticotropin-releasing factor transcription and plasma corticosterone release. Indeed, lipopolysaccharide caused a selective expression of corticotropin-releasing factor primary transcript in the paraventricular nucleus of the hypothalamus and this effect was significantly reduced by treatment with the serotonin inhibitor. However, basal expression of corticotropin-releasing factor messenger RNA across the brain (bed nucleus of the stria terminalis, medial preoptic area, paraventricular nucleus of the hypothalamus, central nucleus of the amygdala, etc.) was not affected by the para-chlorophenylalanine treatment. These results suggest that the integrity of serotonin pathways plays a role in the neuronal activity triggered by the systemic endotoxin insult. The fact that serotonin depletion largely prevented activation of neurosecretory parvocellular neurons of the paraventricular nucleus of the hypothalamus and neuroendocrine corticotropin-releasing factor gene transcription in response to immunogenic challenge provides the evidence that serotonergic system is part of the brain circuitry involved in the corticotroph axis-immune interface.

Fluoxetine induces the transcription of genes encoding c-fos, corticotropin-releasing factor and its type 1 receptor in rat brain

Fluoxetine is a serotonin re-uptake blocker commonly used to treat endogenous depression. The present experiments were carried out to assess the effects of fluoxetine on c-fos induction throughout the rat brain. In addition, intron-directed in situ hybridization analysis was used to examine fluoxetine regulation of corticotropin-releasing factor heteronuclear gene transcription in the paraventricular nucleus of the hypothalamus. Because the actions of corticotropin-releasing factor are mediated by membrane-bound corticotropin-releasing factor type 1 receptors, we also evaluated the stimulation of such receptors after acute fluoxetine exposure. The immediate-early gene, c-fos, was markedly induced in several telencephalic and diencephalic brain structures. For instance, a strong hybridized signal was apparent 30 min after fluoxetine (10 mg/kg; intraperitoneal) administration in the caudate putamen, septal nucleus, bed nucleus of stria terminalis, anterodorsal preoptic area, paraventricular nucleus, supraoptic nucleus, ventromedial hypothalamus and posterior hypothalamic nucleus. In addition, c-fos-expressing neurons were also evident in discrete amygdaloid nuclei. This nuclear induction was brief in duration, as levels of the immediate-early gene were mostly undetectable 90 min after drug administration. In contrast to the extensive induction of c-fos by fluoxetine throughout the brain parenchyma, elevation of corticotropin-releasing factor heteronuclear RNA levels were confined exclusively to neurosecretory nerve cells of the paraventricular nucleus, with peak levels detected 30 min after fluoxetine exposure. Therefore, the time-course of corticotropin-releasing factor heteronuclear RNA closely paralleled that of c-fos. Significant changes in corticotropin-releasing factor type 1 receptor messenger RNA levels were also observed in the paraventricular nucleus but with a slow incremental biosynthesis of the receptor messenger RNA, as high levels were discernible only 360 min after fluoxetine treatment. Finally, we failed to detect sex-related differences in the acute response to fluoxetine, as both female and male rat brains showed a comparable induction of c-fos, corticotropin-releasing factor heteronuclear RNA and corticotropin-releasing factor type 1 receptor expression within parvocellular neurosecretory nerve cells that govern the stress response. All of these findings are discussed in terms of specific sequences of nuclear events that couple fluoxetine-based serotonin input with changes in gene expression in selective neurons.

Job strain and ambulatory blood pressure among female white-collar workers

OBJECTIVES

The association between job strain and ambulatory blood pressure was studied among female white-collar workers.

METHODS

This cross-sectional investigation studied 210 women in high- or low-strain jobs randomly selected from 3183 women of all ages, employed as white-collar workers. The women wore an ambulatory blood pressure monitor for 24 hours during a workday. Mean blood pressures were calculated. Psychological demands and decisional latitude were measured twice (14 months before and 7 days before the blood pressure measurement) with 2 scales recommended by Karasek.

RESULTS

Significant differences in blood pressure were found according to current job strain among the women holding a university degree. Their mean blood pressures during work were significantly higher [8.0 mm Hg (1.1 kPa) systolic and 6.4 mm Hg (0.8 kPa) diastolic blood pressure] in the high-strain group than in the low-strain group. Statistically significant elevations in blood pressure over the 24-hour period were also found for women with a university degree. Cumulative exposure to high strain over 14 months was also significantly associated with high systolic blood pressure at work, in the evening, and over a 24-hour period irrespective of other factors related to blood pressure. Among the women without a university degree, the blood pressure differences observed between the job strain groups were less than 1 mm Hg (0.1 kPa) and not statistically significant.

CONCLUSIONS

These results provide support for the effect of job strain on ambulatory blood pressure only among female white-collar workers holding a university degree.

Expression and neuropeptidergic characterization of estrogen receptors (ERalpha and ERbeta) throughout the rat brain: anatomical evidence of distinct roles of each subtype

The recent cloning of a second estrogen receptor (ER) provided a new tool to investigate and clarify how estrogens are capable of communicating with the brain and influence gene expression and neural function. The purpose of the present study was to define the neuroanatomical organization of each receptor subtype using a side-by-side approach and to characterize the cellular population (s) expressing the ERbeta transcript in the endocrine hypothalamus using immunohistochemistry combined with in situ hybridization. Axonal transport inhibition was accomplished to cause neuropeptide accumulation into the cytoplasm and thus facilitate the detection of all positive luteinizing hormone-releasing hormone (LHRH), corticotropin-releasing factor (CRF), vasopressin (AVP), oxytocin (OT), gastrin-related peptide (GRP), and enkephalin (ENK) neurons. The genes encoding either ERalpha or -beta were expressed in numerous limbic-associated structures, and fine differences were found in terms of intensity and positive signal. Such phenomenon is best represented by the bed nucleus of the stria terminalis (BnST) and preoptic area/anterior hypothalamus, where the expression pattern of both transcripts differed across subnuclei. The novel ER was also found to be expressed quite exclusively in other hypothalamic nuclei, including the supraoptic (SON) and selective compartments (magnocellular and autonomic divisions) of the paraventricular nucleus (PVN). A high percentage of the ERbeta-expressing neurons located in the ventro- and dorsomedial PVN are of OT type; 40% of the OT-ir cells forming the medial magnocellular and ventromedial parvocellular PVN showed a clear hybridization signal for ERbeta mRNA, whereas a lower percentage (15-20%) of OT neurons were positive in the caudal parvocellular PVN and no double-labeled cells were found in the rostral PVN and other regions of the brain with the exception of the SON. Very few AVP-ir neurons expressing ERbeta transcript were found throughout the rat brain, although the medial PVN displayed some scattered double-labeled cells (<5%). Quite interestingly, the large majority of the ERbeta-positive cells in the caudal PVN were colocalized within CRF-ir perikarya. Indeed, more than 60-80% of the CRF-containing cells located in the caudolateral division of the parvocellular PVN exhibited a positive hybridization signal for ERbeta mRNA, whereas very few (<5%) neuroendocrine CRF-ir parvocellular neurons of the medial PVN expressed the gene encoding ERbeta. A small percentage of ERbeta-expressing cells in the dorsocaudal and ventromedial zones of the parvocellular PVN were also ENK positive. The ventral zone of the medial parvocellular PVN also displayed GRP-ir neurons, but no convincing hybridization signal for ERbeta was detected in this neuronal population. Finally, as previously described for the gene encoding the classic ER, LHRH neurons of both intact and colchicine-pretreated animals did not express the novel estrogen receptor. This study shows a differential pattern of expression of both receptors in the brain of intact rats and that ERbeta is expressed at various levels in distinct neuropeptidergic populations, including OT, CRF, and ENK. The influence of estrogen in mediating genomic and neuronal responses may therefore take place within these specific cellular groups in the brains of cycling as well as intact male mammals.

Corticotropin-releasing factor and glucocorticoid receptor (GR) gene expression in the paraventricular nucleus of immune-challenged transgenic mice expressing type II GR antisense ribonucleic acid

The purpose of this study was to investigate the effect of the immune activator lipopolysaccharide (LPS) on the expression of corticotropin-releasing factor (CRF) and glucocorticoid receptor (GR) mRNA in the paraventricular nucleus (PVN) of transgenic mice with impaired GR function caused by endogenous expression of GR antisense RNA. At 3 and 8 wk of age, control and transgenic mice were sacrificed 4.5 h after a single ip administration of LPS (100 micrograms/100 g of body wt) or vehicle. Frozen brains were mounted on a microtome and cut in 20-microns sections. mRNAs encoding CRF and GR were assayed by in situ hybridization histochemistry using 35S-labeled riboprobes, and localization of Fos-immunoreactive (Fos-ir) nuclei was determined by immunocytochemistry. Basal expression of CRF mRNA in the PVN, central nucleus of the amygdala (CeA), and geniculate complex (GN) was similar in the control and transgenic mice. LPS induced a comparable neuronal activation in the PVN of control and transgenic mice as revealed by the number of Fos-ir neurons. Moreover, the endotoxin caused a significant increase in the CRF mRNA levels within the PVN and CeA, an effect observed in both animal models. The endotoxin did not notably modulate CRF expression in other regions, such as GN. Although GR mRNA was expressed in the PVN of control mice under basal conditions, this transcript was not detected in this hypothalamic structure in LPS-treated and transgenic animals. This indicated that endogenous Type II GR mRNA is decreased in the PVN of mice expressing Type II GR antisense RNA and that gene is downregulated by LPS. Hybridization signal for CRF and GR transcripts was not notably altered by the age of mice. These results provide evidence that the basal expression of CRF and the increase of neuroendocrine CRF transcription in response to immunogenic challenges are not significantly affected by impairment of the Type II GR function.

Effect of dexfenfluramine on the transcriptional activation of CRF and its type 1 receptor within the paraventricular nucleus of the rat hypothalamus

1. The present study investigated the effect of intraperitoneal (i.p.) administration of the indirect 5-hydroxytryptamine (5-HT) receptor agonist, dexfenfluramine, on the transcriptional activity of corticotropin-releasing factor (CRF) and its type 1 receptor in the brains of conscious male Sprague-Dawley rats via in situ hybridization histochemistry (ISHH) using both intronic and exonic probe technology. 2. The immediate early gene (IEG) c-fos mRNA was also used as index of cellular activity, whereas localization between CRF-immunoreactive (ir) perikarya and the IEG was accomplished to determine the site of CRF neuronal activation in the brain of dexfenfluramine-treated rats. 3. Thirty minutes, 1, 3, and 6 h after a single injection of either dexfenfluramine (10 mg kg-1) or the vehicle solution, adult male rats (230-260 g) were deeply anaesthetized and rapidly perfused with a 4% paraformaldehyde-borax solution (PF). The brains were removed from the skull, postfixed, and placed in a solution of 4% PF-10% sucrose overnight at 4 degrees C. Frozen brains were mounted on a microtome and cut from the olfactory bulb to the medulla in 30-microns coronal sections. 4. Dexfenfluramine induced a general neuronal activation as indicated by the strong signal of c-fos mRNA in several structures of the brain, including the parietal cortex, caudate putamen, circumventricular organs, medial preoptic area, bed nucleus of the stria terminalis, choroid plexus, choroidal fissure, supraoptic nucleus, paraventricular nucleus of the hypothalamus (PVN), paraventricular nucleus of the thalamus, central nucleus of the amygdala, dorsomedial nucleus of the hypothalamus, laterodorsal tegmental nucleus, locus coeruleus, and several subdivisions of the dorsal vagal complex. In most of these structures, the signal was maximal at 30 min, still strong and positive at 60 min, largely decreased at 3 h, and had completely disappeared 6 h after injection. 5. In the parvocellular division of the PVN, the large majority of CRF-ir perikarya displayed a positive signal for the mRNA encoding c-fos, indicating a profound CRFergic activation within this neuroendocrine nucleus after dexfenfluramine administration. 6. Colocalization between CRF-ir neurones and c-fos positive cells was not detected in any other regions. This selective activation of PVN CRF neurones was also confirmed by the presence of CRF primary transcript; 30 min after i.p. injection of the indirect 5-HT agonist, a positive signal for CRF hnRNA was observed, specifically in the parvocellular PVN. 7. Transcription of the gene encoding the type 1 receptor for CRF was highly stimulated in the PVN following 5-HT activation. Although this hypothalamic nucleus exhibited a barely detectable signal under basal conditions, dexfenfluramine induced a strong signal of CRF1 receptor mRNA in the parvocellular PVN. Interestingly, CRF-ir neurones displayed a positive signal for the mRNA encoding the CRF1 receptor, 3 and 6 h after systemic treatment with dexfenfluramine. 8. These results indicate that although dexfenfluramine can generate a wide neuronal activation throughout the brain, this 5-HT agonist triggers the activity of CRF neurones selectively in the parvocellular division of the PVN, a mechanism possibly related to the activity of hypothalamic-pituitary-adrenal axis. Induction of CRF1 receptor mRNA in CRF cells of the PVN indicates that neuroendocrine CRF neurones can be targeted by CNS CRF under 5-HT stimulation.

Mutation R96W in cytochrome P450c17 gene causes combined 17 alpha-hydroxylase/17-20-lyase deficiency in two French Canadian patients

Congenital adrenal hyperplasia (CAH) is the most frequent cause of adrenal insufficiency and ambiguous genitalia in newborn children. In contrast to CAH caused by 21 alpha-hydroxylase and 11 beta-hydroxylase deficiencies, which impairs steroid formation in the adrenal exclusively, 17 alpha-hydroxylase/17,20-lyase deficiency impairs steroid biosynthesis in the adrenals and gonads. The sequence of CYP17 gene was determined by direct sequencing of asymmetric PCR products in two French-Canadian 46,XY pseudohermaphrodite siblings suffering from combined 17 alpha-hydroxylase/17,20-lyase deficiency. The two patients are homozygous for the novel missense mutation R96W caused by a C to T transition converting codon Arg96 (CGG) into a Trp (TGG) in exon 1. The both parents are heterozygous for this missense mutation. We assessed the effect of the R96W mutation on 17 alpha-hydroxylase/17,20-lyase activity by analysis of mutant enzyme, generated by site-directed mutagenesis, expressed in COS-1 cells. The presence of R96W substitution almost completely abolished the activity of the mutant protein. The present findings provide a molecular explanation for the signs and symptoms of combined 17 alpha-hydroxylase/17,20-lyase deficiency in these two patients and provide useful information on the structure-activity relationships of the P450c17, enzyme.

Nonsalt-losing male pseudohermaphroditism due to the novel homozygous N100S mutation in the type II 3 beta-hydroxysteroid dehydrogenase gene

Recently, the structure of two genes encoding isoenzymes responsible for 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta HSD) activity in the human was elucidated. This activity is an essential step in the biosynthesis of all classes of steroid hormones. In the classic severe form of 3 beta HSD deficiency, patients present with adrenal insufficiency, various degrees of salt loss, and incomplete masculinization in males. Here we report the characterization of the molecular basis of congenital adrenal hyperplasia due to 3 beta HSD deficiency in a male pseudohermaphrodite born from consanguineous parents and having no clinical salt loss. To analyze the structure of the type I and II 3 beta HSD genes of the patient, DNA fragments, generated by polymerase chain reaction amplification of the four exons and the exon-intron boundaries of these genes, were directly sequenced. The patients carried a homozygous missense mutation converting Asn100 to Ser in exon 3 of his type II 3 beta HSD gene. His parents were heterozygous for the same point mutation. The absence of clinical salt loss associated with a male pseudohermaphroditism suggested that 3 beta HSD activity was impaired to different levels in the testes and adrenal. To elucidate whether this N100S missense mutation affected preferentially a steroidogenic pathway, enzymatic activity was analyzed by in vitro analysis of mutant recombinant enzyme generated by site-directed mutagenesis after its transient expression in COS-1 cells. Using homogenates from transfected cells, the N100S 3 beta HSD enzyme showed a Km value for pregnenolone of 25 +/- 3 mumol/L compared with 3.5 +/- 0.2 mumol/L for the normal human type II 3 beta HSD enzyme. Similar results were obtained using dehydroepiandrosterone as substrate. In addition to decreasing apparent affinity, the N100S mutation decreased the relative specific activity (Vmax), leading to a relative specificity (relative Vmax/Km) 2.7% and 11% that of normal type II 3 beta HSD using pregnenolone or dehydroepiandrosterone as substrate, respectively. Moreover, the mutant N100S protein had an apparent decreased affinity for NAD+, with a Km value of 650 +/- 66 mumol/L compared with 20 +/- 2 mumol/L for normal type II 3 beta HSD. Except for the hypothetical effect of local factors, these findings suggest that a very weak residual activity of the normal type II 3 beta HSD enzyme could prevent salt loss, but it was insufficient for normal male sex differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Neuronal activity and neuropeptide gene transcription in the brains of immune-challenged rats

The present study investigated the effect of the acute-phase response of a systemic immune activation on the transcription of various immediate early genes (IEGs) and neuropeptides in the brain of conscious rats. One, 3, 6, 9, and 12 h after a single intraperitoneal (i.p.) administration of either the immune activator lipopolysaccharide (LPS) or the vehicle solution, adult male rats were sacrificed and their brains cut in 30-microns coronal sections. mRNA encoding the IEGs c-fos and nerve growth factor inducible-B (NGFI-B), and neuropeptides corticotropin-releasing factor (CRF), oxytocin (OT), and vasopressin (AVP) were assayed by in situ hybridization histochemistry using a 35S-labeled riboprobes. The primary transcripts [heteronuclear (hn)RNA] for these neuropeptides were also detected using intronic probe technology, and colocalization of c-fos mRNA within CRF, AVP, and OT neurons was determined by means of a combination of immunocytochemistry and in situ hybridization techniques on same the brain sections. One h after LPS treatment, both c-fos and NGFI-B genes were expressed in the parvocellular division of the paraventricular nucleus (PVN) of the hypothalamus. The medial preoptic area/organum vasculosum of the lamina terminalis, the supraoptic nucleus (SON), the magnocellular division of the PVN, the arcurate nucleus/median eminence, the locus coeruleus, the nucleus of the solitary tract, and the area postrema also exhibited a strong signal for these two transcripts 3 h after endotoxin administration. A smaller but a significant c-fos expression was observed in various structures, including the dorsomedial hypothalamic area, the central nucleus of the amygdala, the ventral part of the tuberomammillary nucleus, the laterodorsal tegmental nucleus, the external lateral part of the parabrachial nucleus, the dorsal division of the ambiguus nucleus, and the lateral reticular nucleus of LPS-injected rats. The signal for c-fos and NGFI-B mRNA in most of these brain nuclei reached a maximum at 3 h postinjection, declined at 6 h, and vanished 9 to 12 h after LPS treatment. In the parvocellular nucleus of the PVN, c-fos was largely expressed in CRF-immunoreactive (ir) neurons, whereas in the magnocellular part of that nucleus and in the SON, this transcript was colocalized in numerous OT-ir and few AVP-ir neurons. Relative levels of CRF mRNA in the parvocellular PVN were also significantly increased 6 h following LPS, but endotoxin did not alter the genetic expression of this stress-related neuropeptide in other brain regions.(ABSTRACT TRUNCATED AT 400 WORDS)

Immune challenge and immobilization stress induce transcription of the gene encoding the CRF receptor in selective nuclei of the rat hypothalamus

The present study investigated the effect of intraperitoneal (i.p.) administration of endotoxin lipopolysaccharide (LPS) and immobilization stress on the genetic expression of corticotropin-releasing factor receptor (CRF-R) in the brains of conscious male Sprague-Dawley rats. One group of rats was killed at 1, 3, 6, 9, and 12 hr after a single intraperitoneal injection of either the LPS (250 micrograms/100 gm of body weight) or the vehicle solution; the other group was killed before, immediately after, 1.5, 3, 6, and 12 hr after a 90 min acute session of immobilization stress. Rats were deeply anesthetized and rapidly perfused with a solution of 4% paraformaldehyde-borax. Frozen brains were mounted on a microtome and cut from the olfactory bulb to the medulla in 30 microns coronal sections. mRNA encoding the rat CRF-R was assayed by in situ hybridization histochemistry using a 35S-labeled riboprobe, and CRF-R localization within CRF-immunoreactive neurons in the PVN was determined using a combination of immunocytochemistry and in situ hybridization techniques. Strong basal levels of CRF-R transcripts were observed in several regions of the brain (piriform cortex, medial and basolateral nuclei of the amygdala, red nucleus, pontine gray, cerebellum, laterodorsal tegmental nucleus, caudal division of the zona incerta, nucleus incertus, spinal and principal sensory nuclei of the trigeminal nerve, and various layers of the cortex). A low to moderate signal was also detected in multiple sites (medial septal nucleus, nucleus of the diagonal band, supraoptic nucleus, arcuate nucleus of the hypothalamus, interpeduncular nucleus, and nucleus prepositus). Whereas vehicle-treated and control rats displayed hardly detectable signals of CRF-R mRNA in the paraventricular nucleus (PVN), CRF-R gene transcription was highly stimulated by LPS administration and immobilization stress in this hypothalamic structure. Indeed, the CRF-R mRNA signal was positive in the dorsomedial parvocellular PVN 3 hr after LPS injection, strong and maximum in both parvo- and magno-PVN at 6 hr postinjection, and declined 9 and 12 hr after treatment. Similarly, 90 min and 3 hr after the immobilization session, mRNA encoding the CRF-R was highly expressed in the parvo-PVN and totally vanished 12 hr after the stress. A lower but significant increase in the CRF-R transcript signal was also observed in the supraoptic nucleus 6 hr after the LPS treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Functional characterization of the novel L108W and P186L mutations detected in the type II 3 beta-hydroxysteroid dehydrogenase gene of a male pseudohermaphrodite with congenital adrenal hyperplasia

Two isoenzymes are responsible for 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta-HSD) activity in humans. We analyzed the structure of types I and II 3 beta-HSD genes in a male pseudohermaphrodite suffering from a severe salt-losing form of congenital adrenal hyperplasia. We did not detect any mutation in the type I 3 beta-HSD gene, but we found two different missense mutations in exon IV of the type II 3 beta-HSD gene of the patient; a conversion of codon Leu108 into a Trp (L108W) inherited from his mother and a conversion of codon Pro186 into a Leu (P186L) inherited from his father. We assessed the effect of the L108W and P186L mutations on 3 beta-HSD activity by in vitro analysis of mutant enzymes expressed in heterologous COS-1 cells. Using homogenates from transfected cells, the Km values for PREG were 7 +/- 2 and 8 +/- 2 microM for the recombinant L108W and P186L enzymes, respectively, compared with 2.2 +/- 0.2 microM for the normal type II 3 beta-HSD enzyme. Moreover, Km values for NAD+ were much higher for the L108W and P186L proteins, being 678 +/- 166 and 920 +/- 351 microM, respectively, compared with 24 +/- 3 microM for the normal type II 3 beta-HSD enzyme. Vmax values for PREG and NAD+ were lower for both mutant enzymes; thus, the in vitro overall efficiency, relative to the normal enzyme, is approximate as 0.3% and 0.2% for the L108W and P186L enzymes, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection and functional characterization of the novel missense mutation Y254D in type II 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) gene of a female patient with nonsalt-losing 3 beta HSD deficiency

Three beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta HSD) deficiency is a form of congenital adrenal hyperplasia characterized by severe impairment of steroid biosynthesis in the adrenals and gonads. To better understand the molecular basis of the phenotypic heterogeneity found in 3 beta HSD deficiency, we analyzed the structure of type I and II 3 beta HSD genes in a female patient with nonsalt-losing 3 beta HSD deficiency diagnosed at puberty. We directly sequenced DNA fragments generated by polymerase chain reaction amplification of the four exons, the exon-intron boundaries, and the 5'-flanking regions of each gene. No mutation was detected in the type I 3 beta HSD gene, which is the predominant species expressed in the placenta and peripheral tissues. We detected a novel missense mutation, Y254D, in one allele of the patient's type II 3 beta HSD gene, which is the almost exclusive type expressed in the adrenals and gonads. The influence of the Y254D mutation on enzymatic activity was assessed by analyzing the recombinant mutant enzyme generated by site-directed mutagenesis after its transient expression in COS-1 monkey kidney cells. Recombinant mutant type II 3 beta HSD enzyme carrying the Y254D substitution exhibits no detectable activity with C21 delta 5-steroid pregnenolone or C19 delta 5-steroid dehydroepiandrosterone used as substrate. The absence of restriction fragment length polymorphism by Southern blot analysis and the finding that all of the amplified DNA fragments possess the expected length suggest the absence of deletions, duplications, or re-arrangements in the other allele. A putative second mutation could be located farther than 1427 basepairs upstream of the initiation codon, thus potentially affecting the normal expression of this gene or within intronic regions, generating an alternative aberrant splicing site. These are possibilities that remain to be elucidated. The present findings, which describe the novel missense mutation Y254D in the human type II 3 beta HSD gene, provide useful information on the structure-activity relationships of the 3 beta HSD superfamily.

Molecular basis of congenital adrenal hyperplasia due to 3 beta-hydroxysteroid dehydrogenase deficiency

Congenital adrenal hyperplasia is the most frequent cause of adrenal insufficiency and ambiguous genitalia in newborn children. In contrast to congenital adrenal hyperplasia due to 21-hydroxylase and 11 beta-hydroxylase deficiencies, which impair steroid formation in the adrenal cortex, exclusively, classical 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency affects steroid biosynthesis in the gonads as well as in the adrenals. The structures of the highly homologous type I and II 3 beta-HSD genes have been analyzed in three male pseudohermaphrodite 3 beta-HSD deficient patients from unrelated families in order to elucidate the molecular basis of classical 3 beta-HSD deficiency from patients exhibiting various degrees of severity of salt losing. The nucleotide sequence of DNA fragments generated by selective polymerase chain reaction amplification that span the four exons, the exon-intron boundaries, as well as the 5'-flanking region of each of the two 3 beta-HSD genes have been determined in the three male patients. The five point mutations characterized were all detected in the type II 3 beta-HSD gene, which is the gene predominantly expressed in the adrenals and gonads, while no mutation was detected in the type I 3 beta-HSD gene, predominantly expressed in the placenta and peripheral tissues. The two male patients suffering from severe salt-losing 3 beta-HSD deficiency are compound heterozygotes, one bearing the frame-shift mutation 186/insC/187 and the missense mutation Y253N, while the other bears the nonsense mutation W171X and the missense mutation E142K. The influence of the detected missense mutations on enzymatic activity was assessed by in vitro expression analysis of mutant recombinant enzymes generated by site-directed mutagenesis in heterologous mammalian cells. Recombinant mutant type II 3 beta-HSD enzymes carrying Y253N or E142K substitutions exhibit no detectable activity. On the other hand, the nonsalt-losing patient is homozygous for the missense mutation A245P. This mutation decreases 3 beta-HSD activity by approximately 90%. The present findings, describing the first missense mutations in the human type II 3 beta-HSD gene, provide unique information on the structure-activity relationships of the 3 beta-HSD superfamily. Moreover, the present findings provide a molecular explanation for the enzymatic heterogeneity responsible for the severe salt-losing form to the clinically inapparent salt-wasting form of classical 3 beta-HSD deficiency.(ABSTRACT TRUNCATED AT 400 WORDS)