Testing the validity of c-fos expression profiling to aid the therapeutic classification of psychoactive drugs

RATIONALE

Different stimuli, including pharmacological stimuli, induce different neuroanatomical profiles of c-fos expression. Can these profiles be used in classifying psychoactive drugs and predicting therapeutic utility?

OBJECTIVE

To test the validity of c-fos expression profiling to aid therapeutic classification.

METHODS

Anxiolytics, antidepressants, antipsychotics and psychostimulants were compared. (i) A meta-analysis was performed and profiles compiled from literature reports of changes in c-fos expression in rat brain regions, measured by in situ hybridisation histochemistry or immunohistochemistry, after acute injection of psychoactive drugs. (ii) Male rat brains were profiled for changes in c-fos mRNA expression induced by acute injection of psychoactive drugs.

RESULTS

(i) The meta-analysis showed that anxiolytics activate few (mostly stress-related) brain regions; antidepressants activate more regions, including the central amygdaloid nucleus; antipsychotics activate more regions still, including the nucleus accumbens and striatal areas; and psychostimulants activate the greatest number of all, including the most cortical regions (especially the piriform cortex). Profiles also varied within drug classes. (ii) Our experimental profiles confirmed and extended meta-analysis profiles, showing more downregulation. (iii) Sites activated by mirtazapine (an antidepressant not previously profiled) matched those of the antidepressant imipramine.

CONCLUSIONS

(i) Differences between drug classes support their classification by means of c-fos profiling. Differences within classes may reflect mechanistic variations. (ii) Greater downregulation in our experiments might be because of inclusion of low, clinically relevant, drug doses and fuller coverage of brain regions. (iii) The agreement between mirtazapine and imipramine increases our confidence in the validity of c-fos expression profiling to aid drug classification and predict therapeutic utility.

Health behavior associated with influenza vaccination among healthcare workers in long-term-care facilities

OBJECTIVE

To investigate the health behavior associated with influenza vaccination among healthcare workers (HCWs) in long-term-care facilities.

DESIGN

A cross-sectional, self-administered survey of HCWs, augmented with focus groups to further examine attitudes toward influenza vaccination.

SETTING

Two long-term-care facilities participated in the survey. The focus groups were held at one of the two facilities.

PARTICIPANTS

All HCWs were invited to participate in the survey and all nonmanagerial staff members were invited to participate in the focus groups. The response rate for the survey was 58% (231 of 401).

RESULTS

Vaccinated HCWs had a more positive attitude toward influenza vaccination and a greater belief that the vaccine is effective. This was not accompanied by differences in vaccine knowledge or values of potential preventive outcomes. Nonvaccinated respondents were more likely to believe that other preventive measures, such as washing hands, taking vitamins and supplements, eating a nutritious diet, exercising, and taking homeopathic or naturopathic medications, were more effective than vaccination. Additional findings from the focus groups suggest that HCWs believe that the main purpose of influenza vaccination programs is to protect residents' health at the expense, potential harm, and burden of responsibility of the staff.

CONCLUSIONS

This study identifies challenges to and opportunities for improving vaccination rates among HCWs. A message that emphasizes the health benefits of vaccination to staff members, such as including vaccination as part of a staff "wellness" program, may improve the credibility of influenza immunization programs and coverage rates.

Resolution of P-glycoprotein and non-P-glycoprotein effects on drug permeability using intestinal tissues from mdr1a (-/-) mice

1. Intestinal xenobiotic transporters are a significant barrier to the absorption of many orally administered drugs. P-glycoprotein (PGP) is the best known, but several others, including members of the multidrug resistance-associated protein (MRP) family, are also expressed. Definitive information on their precise effect on intestinal drug permeability is scarce due to a lack of specific inhibitors and the difficulty of studying non-PGP activity in the presence of high PGP expression. 2. We have investigated the in vitro use of intestinal tissues from PGP knockout (mdr1a (-/-)) mice as a tool for dissecting the mechanisms of intestinal drug efflux. The permeability characteristics of digoxin (DIG), paclitaxel (TAX) and etoposide (ETOP) were measured in ileum from mdr1a (-/-) and wild-type (FVB) mice mounted in Ussing chambers. 3. DIG and TAX exhibited marked efflux across FVB tissues (B-A : A-B apparent permeability (P(app)) ratio 10 and 17 respectively) which was absent in mdr1a (-/-) tissues, confirming that PGP is the sole route of intestinal efflux for these compounds. The A-B P(app) of both compounds was 3 - 5 fold higher in mdr1a (-/-) than in FVB. 4. Polarized transport of ETOP in FVB tissues was reduced but not abolished in mdr1a (-/-) tissues. Residual ETOP efflux in mdr1a (-/-) tissues was abolished by the MRP inhibitor MK571, indicating involvement of both PGP and MRP. 5. MK571 abolished calcein efflux in mdr1a (-/-) tissues, while quinidine had no parallel effect in FVB tissues, suggesting involvement of MRP but not PGP. 6. Tissues from mdr1a (-/-) mice provide a novel approach for investigating the influence of PGP ablation on intestinal permeability and for resolving PGP and non-PGP mechanisms that modulate drug permeability.

An outbreak of Serratia marcescens associated with the anesthetic agent propofol

BACKGROUND

In October 1999, 7 patients with postoperative infections caused by Serratia marcescens were identified at a community hospital in Ontario, Canada. We describe the investigation of this outbreak.

METHODS

We undertook a case-control study to determine risk factors associated with infection. Case subjects consisted of patients who had undergone surgery and acquired bacteremia or wound infections that, when cultured, grew S marcescens. Control subjects were selected from the cohort of patients who underwent surgery at the same hospital during the outbreak period. Chart reviews were conducted for case and control subjects. Environmental samples were taken from medications and liquids in the operating rooms and from one health care professional who was involved in all the cases. S marcescens isolates were forwarded to a reference laboratory for pulsed field gel electrophoresis.

RESULTS

We identified 7 case subjects and 29 control subjects. Five patients had bacteremia and 2 patients had wound infections. Two patients with bacteremia died. All patients with bacteremia or wound infections were exposed to a single anesthetist (anesthetist A) and were administered the anesthetic medication propofol. These patients were more than 40 times more likely to have had anesthetist A administer their anesthetic (OR 41.6, 95% CI 3.6-1120) and 22 times more likely to have received propofol (OR 22, 95% CI 2.1-550) than were control subjects. None of the environmental samples or cultures from anesthetist A were positive for S marcescens. Six of the 7 human isolates had an identical pulsed field gel electrophoresis pattern, and the seventh was untypable.

CONCLUSIONS

This outbreak of postoperative infections was very strongly linked to the use of propofol by one anesthetist. Health care professionals must follow strict aseptic techniques when using propofol and should review these techniques regularly.

Use of Neo-melubrina, a banned antipyretic drug, in San Diego, California: a survey of patients and providers

BACKGROUND

Dipyrone is an antipyretic drug that has been associated with agranulocytosis. It is banned in the United States but is available in Mexico under the name Neo-melubrina.

OBJECTIVES

To define the use of Neo-melubrina in the Hispanic population of 2 San Diego, California, community clinics and to determine local physicians' and nurse practitioners' awareness of the drug and its risks.

DESIGN

Patient survey and provider survey.

PARTICIPANTS

PATIENTS

200 parents of Hispanic pediatric patients. Providers: members of San Diego chapters of the American Academy of Pediatrics, the American Academy of Family Physicians, and the California Coalition of Nurse Practitioners.

MAIN OUTCOME MEASURES

Self-reported use of Neo-melubrina by patients, and provider awareness of Neo-melubrina and its most significant side effects.

RESULTS

Of the 200 patients, 76 (38.0%) reported a lifetime use of Neo-melubrina. Most (56%) used it for both pain and fever. Most providers were unable to correctly identify why Neo-melubrina might be used or its adverse effects. Physicians answered correctly more often than nurse practitioners and pediatric providers more often than family medicine providers. Providers who trained within 75 miles of the US-Mexico border, who reported a patient population of more than 50% Hispanic, and who were resident physicians at the time of the survey were most likely to answer correctly.

CONCLUSIONS

Neo-melubrina has been used by a substantial percentage of Hispanic patients in the community clinics surveyed. Many San Diego health care providers are unaware of this medication and may, therefore, miss opportunities to educate patients about safer alternatives.

Mu- and delta-opioid receptor antagonists reduce levodopa-induced dyskinesia in the MPTP-lesioned primate model of Parkinson's disease

Long-term treatment of Parkinson's disease with levodopa is complicated by the emergence of involuntary movements, known as levodopa-induced dyskinesia. It has been hypothesized that increased opioid transmission in striatal output pathways may be responsible for the generation of dyskinesia. In this study, we have investigated the effect of blockade of opioid peptide transmission on levodopa-induced dyskinesia in a primate model of Parkinson's disease-the MPTP-lesioned marmoset. Coadministration of nonselective and mu- or delta-subtype-selective opioid receptor antagonists with levodopa resulted in a significant decrease in dyskinesia. There was no attenuation of the anti-parkinsonian actions of levodopa. These data suggest that specific mu- or delta-opioid receptor antagonists might be applicable clinically in the treatment of levodopa-induced dyskinesia in Parkinson's disease.

Neural mechanisms underlying peak-dose dyskinesia induced by levodopa and apomorphine are distinct: evidence from the effects of the alpha(2) adrenoceptor antagonist idazoxan

Dyskinesia, secondary to dopamine replacement therapy, is the major complication of currently available therapies for Parkinson's disease. Alpha(2) adrenoceptor antagonists, such as idazoxan, can significantly reduce levodopa-induced dyskinesia in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned, nonhuman primate model of Parkinson's disease and in human. This action of adrenoceptor antagonists may involve blockade of the actions of noradrenaline synthesised from levodopa. We hypothesise that, because dopamine receptor agonists, such as apomorphine, cannot be metabolised to produce noradrenaline, activation of adrenoceptors may not be involved in dyskinesia produced by such agents. If this were the case, idazoxan would not be expected to reduce apomorphine-induced dyskinesia. MPTP-lesioned marmosets with stable dyskinesia induced by prolonged levodopa therapy were given an acute challenge with apomorphine (0.3 mg/kg subcutaneously) or levodopa (8.0 mg/kg orally), these doses produced equivalent peak-dose dyskinesia. Idazoxan (2.5 mg/kg p.o.), or vehicle, was then administered with either apomorphine or levodopa. Idazoxan abolished levodopa-induced dyskinesia but did not affect apomorphine-induced dyskinesia (P < 0.05 and P > 0.05, respectively, Wilcoxon matched pairs test). Idazoxan also extended the anti-parkinsonian actions of levodopa but did not affect those of apomorphine. The pharmacological characteristics of the neural mechanisms underlying levodopa-induced dyskinesia and apomorphine-induced dyskinesia in parkinsonism thus appear to be distinct, at least with respect to the involvement of alpha(2) adrenoceptors. Specifically, levodopa, but not apomorphine-induced dyskinesia, involves activation of adrenoceptors. This finding may have major implications for understanding dyskinesia and should be borne in mind when designing clinical studies in which levodopa or dopamine receptor agonist challenges are employed to assess potential anti-dyskinetic properties of drugs.

Potentiometric and spectroscopic studies on the dimethyltin(IV) complexes of 2-hydroxyhippuric acid

Equilibrium and spectroscopic (1H, 13C NMR and 119Sn Mössbauer) studies in aqueous solution are reported for dimethyltin(IV) complexes of 2-hydroxyhippuric acid (Sal-Gly). Below pH 4, oxygen-coordinated complexes MLH and ML are formed. In the pH range 5-8.5, the species MLH(-1), predominates at any metal-to-ligand ratio. The ligand exchange of this species is slow on the NMR time scale, which allows its structural characterization by NMR spectroscopy: the coordination polyhedron around the tin atom is distorted trigonal bipyramidal, with tridentate [O-,N-,COO-] coordination of Sal-Gly, involving two equatorial methyl groups. The NMR results reveal that the main cause of the distortion of the polyhedron is the large CH3-Sn-CH3 angle of 136+/-4 degrees. The presented results supplement the data available on the dimethyltin(IV)-promoted amide deprotonation of peptides, and provide further arguments for the fundamental role of the carboxylate as an anchoring group in this process.

Leptin and the regulation of food intake and the neuroendocrine axis in sheep

1. Leptin is secreted by fat and acts on the brain. 2. Central infusion of leptin reduces food intake but does not alter endocrine secretions in normally fed sheep. 3. Leptin treatment can correct for altered hormonal secretion in fasted animals. 4. Alterations in bodyweight (leptin status) affect the expression of a number of genes in the hypothalamus that are involved in the regulation of food intake and neuroendocrine function. 5. Leptin receptors are found in both the hypothalamus and pituitary and direct action of leptin can be demonstrated on the somatotrophs in the pituitary.

Translation and linguistic validation of a disease-specific quality of life measure for cystic fibrosis

OBJECTIVE

To develop a conceptually and semantically valid English version of a French disease-specific measure of quality of life for children, adolescents, and adults with cystic fibrosis (CF).

METHODS

Following a backward and forward translation of the measure, 60 participants, including 20 children, 20 parents, and 20 adolescents/young adults completed the Cystic Fibrosis Questionnaire (CFQ) and a series of cognitive probes evaluating their understanding of the items and response choices.

RESULTS

Semantic and conceptual problems with the items were identified and modified for the second set of cognitive interviews. Response distributions across items and ages were adequate, and the predicted associations between disease severity and quality of life were obtained.

CONCLUSIONS

The English version of the CFQ appears to be a linguistically valid measure of quality of life for patients with CF. A national validation study is now under way to test the psychometric properties of the measure.

Antiparkinsonian actions of ifenprodil in the MPTP-lesioned marmoset model of Parkinson's disease

Dopamine-replacement strategies form the basis of most symptomatic treatments for Parkinson's disease. However, since long-term dopamine-replacement therapies are characterized by many side effects, most notably dyskinesia, the concept of a nondopaminergic therapy for Parkinson's disease has attracted great interest. To date, it has proved difficult to devise a nondopaminergic therapy with efficacy comparable to that of dopamine replacement. In animal models of Parkinson's disease, loss of striatal dopamine leads to enhanced excitation of striatal NR2B-containing NMDA receptors. This is responsible, in part at least, for generating parkinsonian symptoms. Here we demonstrate that, in the MPTP-lesioned marmoset, monotherapy with the NR2B-selective NMDA receptor antagonist, ifenprodil, administered de novo, has antiparkinsonian effects equivalent to those of l-DOPA (administered as its methyl ester form). In MPTP-lesioned marmosets, median mobility scores, following vehicle-treatment were 12.5/h (range 6-21), compared to 61/h (range 26-121) in normal, non-MPTP-lesioned animals. Following ifenprodil (10 mg/kg) treatment in MPTP-lesioned marmosets, the median mobility score was 66/h (range 34-93), and following l-DOPA (10 mg/kg i.p.) treatment 89/h (range 82-92). The data support the proposal that NR2B-selective NMDA receptor antagonists have potential as a nondopaminergic monotherapy for the treatment of parkinsonian symptoms when given de novo.

Difference-frequency-based tunable absorption spectrometer for detection of atmospheric formaldehyde

High-sensitivity detection of formaldehyde (CH2O) at 3.5315 micrometers (2831.64 cm-1) is reported with a diode-laser-pumped, fiber-coupled, periodically poled LiNbO3 spectroscopic source. This source replaced the Pb-salt diode laser Dewar assembly of an existing tunable diode-laser absorption spectrometer designed for ultrasensitive detection of CH2O. Spectra are recorded with 2f-modulation spectroscopy and zero-air rapid background subtraction. Initial measurements reported here, determined from multiple measurements of a flowing 7.7 parts per billion by volume (ppbv, parts in 10(9)) CH2O in air mixture, indicate replicate precisions as low as 0.24 ppbv.

Nurse anesthesia practice and research--a worldwide need

In 1992, nurse anesthetists from 94 countries participated in our transnational research by completing surveys (in English, French, German, or Spanish) and providing descriptions about their practice, education, and regulation. Five years later (1997), nurse anesthetists from 81 countries completed expanded and revised questionnaires. Their responses validated the 1992 findings that nurses may be the main administerers of anesthesia in many countries. They are administering both general and regional anesthesia, in rural and urban areas in all regions of the world, and in countries from all levels of development, working with and without anesthesiologists. Their major duties are primarily those that are performed inside operating rooms, a factor that may be contributing to a lack of visibility of the profession. In order to contribute to both clinical and health policy decision making, nurse anesthetists must first document their practice and then participate in collaborative research at the local, regional, national, and international levels.

Priority-setting for nursing research in the Republic of China

The question of how public funds for research should be allocated has led to participatory priority-setting in prosperous democracies like Taiwan, Republic of China. Useful criteria for research priorities are scientific merit, social benefit and feasibility. Taking a health needs approach and using these criteria, nearly 200 nurses from service and education in a national forum participated in describing research priorities. Through the group method of idea-writing, for clinical nursing, of high priority were assessing quality, care of the elderly, and preventing infectious disease. For nursing education, research addressing advanced role preparation and bridging nursing education and practice were priorities. For nursing management, research of highest priority pertained to economic evaluation, personnel administration, and effectiveness. These suggestions from the deliberation of a committed group of nurses can help shape future national decisions about research funding and training.

Characterisation of fatty acid multilayers using a TSM biosensor

Thickness shear mode (TSM) biosensors have many potential applications within the pharmaceutical sciences as a means of measuring mass changes in the nanogram range, film thickness, viscosity and shear moduli. This study addresses the possible use of the TSM sensor as a biosensor for measuring drug partition coefficients. In order to realise this potential, some fundamental understanding is required of the behaviour of lipid films on the sensor. The present study characterises the behaviour of fatty acid multilayers as a suitable model chemical system. Frequency shifts and impedance spectra are presented for multilayers of three fatty acid films coated on to the sensor using a Langmuir-Blodgett trough. The results indicate that the frequency shift is non-linear at lower numbers of fatty acid layers but the response is Sauerbrey-like at higher numbers of layers. Also at high numbers of layers, changes in the impedance spectra indicate viscoelastic behaviour in thicker membranes. An inverse relationship is observed between chain length and frequency shift, which is attributed to variations in the topography of the sensor surface. This work demonstrates the importance of fully characterising the physical behaviour of the lipid multilayers prior to using these systems for the measurement of drug partition coefficients.

The alpha2-adrenergic receptor antagonist idazoxan reduces dyskinesia and enhances anti-parkinsonian actions of L-dopa in the MPTP-lesioned primate model of Parkinson's disease

Dopamine replacement therapy in patients with Parkinson's disease is plagued by the emergence of abnormal involuntary movements known as L-dopa-induced dyskinesias. It has been demonstrated that yohimbine can reduce L-dopa-induced dyskinesia in the MPTP-lesioned primate model of Parkinson's disease. Yohimbine is, among other things, an alpha-adrenergic receptor antagonist. In this study, we demonstrate that the selective and potent alpha2-adrenergic receptor antagonist idazoxan reduces L-dopa-induced dyskinesia in the MPTP-lesioned marmoset model of Parkinson's disease. The alpha2-adrenergic receptor antagonists rauwolscine and yohimbine also reduce L-dopa-induced dyskinesia. Furthermore, we demonstrate that coadministration of idazoxan with L-dopa can provide an anti-parkinsonian action more than twice the length of that seen with L-dopa alone. However, idazoxan as a monotherapy displayed no anti-parkinsonian actions. We propose that idazoxan in combination with L-dopa may provide a novel approach to the treatment of Parkinson's disease that will not only reduce the dyskinetic side effects, but extend the anti-parkinsonian actions of L-dopa. Idazoxan, as an adjunct to dopamine replacement, may prove useful in the treatment of parkinsonian patients at all stages of disease progression.

Effect of repeated L-DOPA, bromocriptine, or lisuride administration on preproenkephalin-A and preproenkephalin-B mRNA levels in the striatum of the 6-hydroxydopamine-lesioned rat

Abnormal involuntary movements, or dyskinesias, plague current symptomatic approaches to the treatment of Parkinson's disease. The neural mechanisms underlying the generation of dyskinesia following repeated l-3,4-dihydroxyphenylalanine (L-DOPA) or dopamine agonist administration in Parkinson's disease remain unknown. However, de novo administration of bromocriptine or lisuride to either l-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned primates or patients can alleviate parkinsonian symptoms without the development of dyskinesia. In this study, we have investigated behavioral responses and alterations in the expression of opioid neuropeptide precursors preproenkephalin-A (PPE-A, encoding methionine- and leucine-enkephalin) and preproenkephalin-B (PPE-B), the precursor encoding dynorphins (dynorphin A1-17 and B1-13, leucine-enkephalin, and alpha-neoendorphin) in striatal output pathways of the 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease. Expression was assessed following repeated L-DOPA, bromocriptine, or lisuride administration. Given the functional organization of basal ganglia circuitry into anatomically discrete parallel circuits, we investigated alterations in peptide expression with reference to the detailed topography of the striatum. Following repeated L-DOPA administration (6.5 mg/kg, b.d., 21 days) in the 6-OHDA-lesioned rat a rotational response was observed. This became markedly enhanced with repeated treatment. We have previously characterized the pharmacology of this enhanced response and have suggested that it is a useful model for the elucidation of the cellular and molecular mechanisms underlying L-DOPA- and dopamine agonist-induced dyskinesia. In contrast to l-DOPA, de novo administration of bromocriptine (1 or 5 mg/kg, b.d., 21 days) or lisuride (0.01 or 0.1 mg/kg, b.d., 21 days) did not lead to an enhanced behavioral response. In vehicle-treated, 6-OHDA-lesioned animals, PPE-A expression was elevated rostrally and dorsally, while PPE-B expression was reduced in the striatum at all rostrocaudal levels. Repeated l-DOPA administration was accompanied by elevations in striatal PPE-B mRNA levels and a further elevation, above lesion-induced levels, in PPE-A expression. This further elevation was restricted to the dorsolateral striatum. However, following repeated bromocriptine or lisuride administration no increase in PPE-B expression was observed and the lesion-induced increase in PPE-A expression was normalized to prelesion levels. Increased PPE-A and PPE-B levels may, through decreasing GABA and glutamate release, respectively, in output nuclei of the basal ganglia, play a role in the development of L-DOPA- and dopamine-agonist induced dyskinesia in Parkinson's disease. These studies suggest that anti-parkinsonian treatments which are not associated with an elevation in PPE-B and/or normalize elevated PPE-A precursor expression, such as NMDA-receptor antagonists or long-acting dopamine D2 receptor agonists, e.g., cabergoline or ropinirole, may reduce dyskinesia in Parkinson's disease.