Methotrexate: long-term safety and efficacy in an Australian consultant rheumatology practice.

BACKGROUND: The aim of this study was to evaluate the rate and cause of methotrexate (MTX) termination in clinical practice, describe the types of toxicities noted, assess the incidence of achieving remission in rheumatoid arthritis (RA) patients and review the appropriateness of current clinical guidelines for monitoring MTX treatment. METHODS: A retrospective, case review of patients seen in a private rheumatology practice attached to a major Sydney Teaching Hospital was undertaken over an 18-year period. The primary outcome was time to cessation of MTX. RESULTS: Seven hundred and ninety patients satisfied the inclusion criteria. MTX was terminated in 272 patients (34.4%). Toxicity-related discontinuation occurred in 93 patients (11.8%) and due to non-adverse reactions in 179 patients. The median duration of therapy in these two groups was 2.0 and 2.9 years, respectively. There was no difference in the average maximum weekly dose of MTX. Of patients with RA, 47.5% were in remission at last follow up. Cox proportional hazards analyses showed that those of the female sex remained on treatment significantly longer than the male sex (hazard ratio (HR) 0.73, 95% confidence interval (CI) 0.57-0.96; P = 0.014); patients with RA remained on treatment significantly longer than patients with seronegative arthritis (HR 0.56, 95%CI 0.42-0.74; P < 0.001). Being of the male sex aged more than 60 years and having a non-RA diagnosis predisposed to stopping MTX earlier. CONCLUSION: MTX is a safe and effective medication. Notable remission rates are achievable in patients with RA with current conventional treatment protocols. MTX has a low toxicity profile and this study stresses the need to re-evaluate and revise the current monitoring guidelines.

Secondary screening for osteoporosis in patients admitted with minimal-trauma fracture to a major teaching hospital.

AIMS: The aim of the present study was to determine: (i) the prevalence of the investigation and treatment of osteoporosis in patients admitted to hospital with a minimal-trauma fracture, (ii) the prevalence of osteoporosis using bone mineral density assessment by dual X-ray absorptiometry (DEXA) in such patients and (iii) a clinical pathway for the management of osteoporosis in such patients. METHODS: A cross-sectional study was undertaken involving all patients admitted with a fracture to Westmead Hospital, Sydney, Australia, between January 1999 and June 2000 (n = 327). Of these, 264 were excluded because of: (i) the fracture following significant trauma (n = 83), (ii) unavailability of medical records for review (n = 38), (iii) nursing home status (n = 37), (iv) previous malignancy (n = 18), (v) deceased (n = 11), (vi) recent osteoporosis screening and/or treatment (n = 18), (vii) refusal to participate (n = 37), (viii) uncontactable (n = 16) and (ix) inadequate English (n = 6). The remaining 63 patients underwent DEXA assessment and the following laboratory investigations: (i) liver function tests, (ii) urea, (iii) electrolytes, (iv) calcium, (v) phosphate, (vi) full blood count, (v) 25-hydroxyvitamin D level and (vi) thyroid-function tests. In men, levels of serum free testosterone, luteinizing hormone, follicle-stimulating hormone and prolactin were also obtained. RESULTS: Of the 63 study participants, 87% of the 47 women were either osteoporotic (T <-2.5) or osteopenic (-2.5

Stimulus properties of tiflucarbine: a novel antidepressant agent.

Tiflucarbine is a structurally novel antidepressant that binds at central serotonin (5-HT) binding sites. There is also evidence that this agent is both a 5-HT1 and a 5-HT2 agonist. To further characterize the serotonergic actions of this agent, tiflucarbine was evaluated in groups of rats trained to discriminate the 5-HT1A agonist 8-OH DPAT, the 5-HT2 agonist DOM, and the nonselective 5-HT agonist 5-OMe DMT from saline. Tiflucarbine resulted in partial generalization in the DOM-trained and in the 8-OH DPAT-trained animals. Although two-thirds of the animals were disrupted, 10 mg/kg of tiflucarbine resulted in stimulus generlization in the 5-OMe DMT-trained animals. It is concluded that tiflucarbine is most likely a nonselective 5-HT agonist.

Changes in septo-hippocampal projections after lateral entorhinal or combined entorhinal-raphé lesions as studied by anterograde tracing methods.

Septal and entorhinal projections to the hippocampus show a considerable overlap in their target structures in the molecular layer of the dentate gyrus (DG) and stratum lacunosum-moleculare of the cornu ammonis (CA). Employing anterograde tracing methods, it was investigated in which way the morphological pattern of the septohippocampal projections were influenced by lateral entorhinal cortex (LEA) lesions. Anterograde filling of neurons from soma to axonal terminals with Phaseolus vulgaris leucoagglutinin (PHA-L) revealed lesion-induced changes in innervation patterns in the DG but not in CA fields. LEA lesions provoke an impressive shift of septo-dentate projections from a predominant middle molecular layer innervation to the outer molecular layer, whereas septal projections to the CA remain unchanged. Comparison with concurrent acetylcholinesterase (AChE) staining and immunocytochemical demonstration of choline acetyltransferase (ChAT) confirm the cholinergic nature of this plasticity response. This response was equally strong in unilateral or bilateral damage to the LEA and was neither enhanced nor inhibited by simultaneous injury to the median raphé nuclei.

Behavioral and physiological detection of classically-conditioned blood pressure reduction.

Spontaneously hypertensive (SH) rats were trained to discriminate the effects of saline injection from the interoceptive stimuli associated with the blood-pressure-reducing effect of clonidine (0.02 mg/kg, IP) in a drug discrimination procedure. Anise/ethanol and ethanol odors were then systematically paired with clonidine and saline treatment, respectively, outside the drug discrimination setting. As the number of pairings increased, the anise/ethanol (but not the ethanol) stimulus, when given alone, came to both reduce blood pressure and to mimic clonidine's interoceptive stimulus to virtually the same extent as clonidine itself. Both responses induced by the conditioned stimulus (CS+; anise/ethanol odor) were antagonized by the noradrenergic alpha-2 receptor antagonist yohimbine at a dose that did not by itself influence blood pressure. These data support the hypothesis that activation of endogenous factors can be elicited by a CS, and that these factors may furthermore act agonistically at central alpha-2 receptors to reduce blood pressure in hypertensive animals.

GTP effects in rat brain slices support the non-interconvertability of M1 and M2 muscarinic acetylcholine receptors.

GTP (guanosine-5'-triphosphate) markedly reduced high-affinity 3H-oxotremorine-M binding to M2 receptors on brain slices in autoradiographic experiments while 3H-pirenzepine binding to M1 receptors was largely unaffected. The distribution of M1 receptors so labelled was also not altered by GTP to include former M2-rich regions, thus indicating that GTP could not, by itself, interconvert high agonist-affinity M2 receptors to M1 receptors.

Cortical projection patterns of magnocellular basal nucleus subdivisions as revealed by anterogradely transported Phaseolus vulgaris leucoagglutinin.

The present paper deals with a detailed analysis of cortical projections from the magnocellular basal nucleus (MBN) and horizontal limb of the diagonal band of Broca (HDB) in the rat. The MBN and HDB were injected iontophoretically with the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L). After immunocytochemical visualization of labeled efferents, the distribution of projections over the cortical mantle, olfactory regions and amygdala were studied by light microscopy. Based on differences in cortical projection patterns, the MBN was subdivided in anterior, intermediate and posterior portions (MBNa, MBNi and MBNp). All subdivisions maintain neocortical projections and are subject to an anterior to posterior topographic arrangement. In the overall pattern, however, the frontal cortex is the chief target. Furthermore, all MBN parts project to various regions of meso- and allocortex, which are progressively more dense when the tracer injection is more anteriorly placed. The most conspicuous finding, however, was a ventrolateral to dorsomedial cortical projection pattern as the PHA-L injection site moved from posterior to anterior. Thus, the posterior MBN projects predominantly to lateral neo- and mesocortex while the anterior MBN sends more fibers to the medial cortical regions. Furthermore, the MBNa is a source of considerable afferent input to the olfactory nuclei and as such should be regarded as a transition to the HDB. The HDB, apart from projecting densely to olfactory bulb and related nuclei, maintains a substantial output to the medial prefrontal cortical regions and entorhinal cortex, as well. Comparison of young vs aged cases indicate that aging does not appear to have a profound influence on cortical innervation patterns, at least as studied with the PHA-L method.

Detailed projection patterns of septal and diagonal band efferents to the hippocampus in the rat with emphasis on innervation of CA1 and dentate gyrus.

The detailed patterns of afferentation to the ammon's horn and dentate gyrus of the hippocampus in the rat were investigated employing the anterograde tracer Phaseolus vulgaris leuco-agglutinin (PHA-L) after punctate iontophoretic injections in the medial septum (MS) and vertical limb of the diagonal band of Broca (VDB). The topographically ordered innervation pattern was different in the regio superior (or CA1) vs. the regio inferior (or CA3) and in the dorsal vs. ventral aspects of ammon's horn and dentate gyrus. The CA1 pyramidal and dentate granule cell layers in the dorsal hippocampus received afferent input almost exclusively from the VDB, whereas those cell layers in ventral hippocampus were supplied from both VDB and MS. The PHA-L labeled projecting fibers could be differentiated into two distinct fiber systems. One class of thick and coarse axons (tentatively called type I fibers) carried fewer but larger terminal boutons and were found to infiltrate the entire stratum oriens, dentate hilus, all layers of the regio inferior and the CA1 str. moleculare. A second, delicate thin (type II) fiber system provided with numerous and passant varicosities showed a much more restricted laminar innervation pattern and appeared to originate from areas in MS-VDB which are rich in AChE-positive neurons. The densest type II fiber networks could be observed in the CA1 subpyramidal and dentate supragranular zones, in the CA1 stratum lacunosum-moleculare and in the dentate middle third molecular layer. This laminar type II innervation pattern showed a remarkable coincidence with the reported distribution of cholinergic marker enzymes. The topographic and spatial organization of the projections described above will be discussed in relation to their possible functional significance.

The interoceptive discriminative stimuli induced by the novel putative anxiolytic TVX Q 7821: behavioral evidence for the specific involvement of serotonin 5-HT1A receptors.

TVX Q 7821 is active in several behavioral models of anxiety in animals and has a high selective affinity for brain serotonin 5-HT1A receptors in binding assays. In order to determine if interaction with 5-HT1A receptors is important for some of the behavioral effects of this compound, 11 rats were trained to reliably discriminate the interoceptive stimuli induced by TVX Q 7821 (10 mg/kg, IP) from those of saline. Following discrimination acquisition, TVX Q 7821 administration resulted in drug-appropriate responding with an ED50 of 1.5 mg/kg, as did other substances with high affinity for the 5-HT1A receptor: 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT, ED50 = 0.16 mg/kg), 5-methoxy-N,N-dimethyltryptamine (5-OMe-DMT, ED50 = 2.5 mg/kg), and buspirone (ED50 = 5.4 mg/kg). Anxiolytics not acting via the 5-HT1A receptor, like diazepam and pentobarbital, did not induce full TVX Q 7821-appropriate responses. In addition, non-selective 5-HT agonists and antagonists such as bufotenin, quipazine, and methysergide, as well as substances with high affinity for the 5-HT1B receptor (m-trifluoromethylphenylpiperazine, TFMPP; 5-methoxy-3(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole succinate, RU 24969) did not substitute for TVX Q 7821. These data support a selective 5-HT1A mechanism of action in vivo for TVX Q 7821 and indicate the suitability of TVX Q 7821 for the investigation of behavioral correlates of the 5-HT1A receptor.

Serotonin receptor subtype mediation of the interoceptive discriminative stimuli induced by 5-methoxy-N,N-dimethyltryptamine.

Male Wistar rats were trained to discriminate the interoceptive effects of 5-methoxy-N,N-dimethyltryptamine (5-OMe-DMT; 1.25 mg/kg, IP) from saline in a two-lever operant chamber. Following discrimination learning, the following drugs (with ED50 dose in mg/kg IP) dose-dependently generalized: lysergic acid diethylamide (LSD, 0.04), 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.11), 6-methoxy-4-(dipropyl-amino)-1,3,4,5-tetrahydrobenz(c,d)indole hydrochloride (BAY R 1531, 0.15), 5-OMe-DMT itself (0.63), ipsapirone (TVX Q 7821, 2.7), and buspirone (3.8). The potencies of these drugs in generalization tests were best correlated with their binding affinities for the 5-HT1A serotonin receptor subtype (as measured by displacement of 3H-ipsapirone in the hippocampus). Drugs not, or only partially generalizing included quipazine, bufotenin, m-trifluoromethylphenylpiperazine (TFMPP), 5-methoxy-3(1,2,3,6-tetrahydropyridine-4-yl)-1H-indole succinate (RU 24969), citalopram, clomipramine, 1,4-dihydro-2,6-dimethyl-3-nitro-4(2-trifluoromethylphenyl)-pyridine-5- carboxylate (BAY K 8644), the buspirone metabolite 1-pyrimidinyl-piperazine (1-PP), methysergide, metergoline, and metitepine. Of the last three compounds with antagonistic activity at 5-HT receptors, as well as ketanserin, pizotifen, and ritanserin, only metitepine and pindolol could fully block the 5-OMe-DMT stimulus. Pizotifen blocked the generalization of quipazine fully, that of 5-OMe-DMT only partially, and that of ipsapirone not at all. These data indicate that the 5-HT1A receptor subtype is strongly involved in the transduction of the interoceptive discriminative stimuli induced by 5-OMe-DMT, with 5-HT2 agonism also playing a possible role.

Effects of N-ethylmaleimide on muscarinic acetylcholine receptor subtype autoradiography and inositide response in rat brain.

Chemical modification of brain muscarinic acetylcholine receptors (mAChr) with N-ethylmaleimide (NEM) has been employed to investigate mAChr-subtype distribution and mediation of the inositide response. 3H-Pirenzepine and 3H-oxotremorine-M were used to autoradiographically localize the M1- and M2-AChr subtypes, respectively, in brain slices. M1- and M2-AChr distribution were observed to be distinct from each other. The presence of 1 mM NEM selectively reduced the labeling of M2-, but not of M1-AChr. These data support the notion that NEM converts the high-affinity M2-AChr to a lower affinity state, without affecting the affinity of the M1-AChr. Also, regional analysis indicated that the M1- and M2-AChr subtypes were not interconvertible by NEM. NEM at 30 microM enhanced the carbamylcholine stimulated labeling of phosphatidic acid from 32Pi in nerve endings from rat forebrain, suggesting that the low affinity M2-AChr may mediate at least a part of the inositide response to cholinergic stimulation.

Direct autoradiographic determination of M1 and M2 muscarinic acetylcholine receptor distribution in the rat brain: relation to cholinergic nuclei and projections.

The autoradiographic distributions of receptors with high affinity for [3H]oxotremorine-M (the M2 receptor) and [3H]pirenzepine (the M1 receptor) were studied in the rat brain. M1 receptors were seen in highest density only in telencephalic structures: cerebral cortex (layers I-II), hippocampus, dentate gyrus, medial and basolateral amygdala, nucleus accumbens and caudate/putamen. M2 receptors were detected throughout the brain, with highest levels observed in cerebral cortical layers III and V, forebrain cholinergic nuclei, caudate/putamen, various thalamic areas, inferior and superior colliculus, interpeduncular and pontine nuclei, brainstem cholinergic nuclei and cervical spinal cord regions. M2 receptors were found to be good markers for cholinergic cell groups and the majority of cholinergic projection areas, whereas M1 receptors were only found in a large sub-group of telencephalic cholinergic projection areas, and the pattern of distribution of receptors in these areas differed from that of M2 receptors. Scatchard analysis of [3H]oxotremorine-M binding to inferior collicular slices revealed one site with a dissociation constant (Kd) of 1.9 nM and a receptor density (Bmax) of 1.4 pmol/mg protein. Our data support the hypothesis that M1 and M2 receptors are physically distinct sub-types of the muscarinic acetylcholine receptor.

Employee voice and employee retention.

This study investigates the relationship between the extent to which employees have opportunities to voice dissatisfaction and voluntary turnover in 111 short-term, general care hospitals. Results show that, whether or not a union is present, high numbers of mechanisms for employee voice are associated with high retention rates. Implications for theory and research as well as management practice are discussed.

Behavioral impairments related to cognitive dysfunction in the autoimmune New Zealand black mouse.

The possibility that autoimmunological disorders involving neuronal constituents as autoantigens can result in measurable behavioral impairments prompted the behavioral analysis of the New Zealand black (NZB) mouse strain, known to have high levels of brain-reactive antibodies. Sensorimotor competence and performance in tasks requiring learning and memory were assessed in 7-10-month-old NZB and contrasted with those of CFW mice. The NZB mice showed pronounced deficits in performance of passive and active shock avoidance responses. These deficits could not be accounted for by the slight sensorimotor disadvantage of NZB mice relative to CFW mice. No difference between the two mouse strains was seen in passive avoidance behavior at 1.5 months of age. It is concluded that NZB mice display a behavioral deficit related to cognitive dysfunction and that autoimmune mechanisms may be involved in the etiology of this deficit. Such behavioral disturbances produced by an autoimmune mechanism may have relevance for the neurological declines observed in aging, since the incidence of autoimmune disorders increases markedly in old age.

Central cholinergic involvement in working memory: effects of scopolamine on continuous nonmatching and discrimination performance in the rat.

Rats were trained to stable baselines of lever pressing on a variable intertrial interval continuous nonmatching to sample schedule (CNM) or on an analogous discrimination schedule. Scopolamine reduced accuracy of CNM performance to a similar extent over the three intertrial (retention) intervals: 2.5, 5, and 10 s, results indicating that the drug did not affect the time-dependent process of retention in working memory. When baseline levels of performance accuracy were similar in the CNM and discrimination tasks (but stimulus discriminability was greater in the CNM task), scopolamine reduced accuracy equally in the two procedures. Effects of scopolamine on accuracy of noncorrection trial CNM performance were simulated by reducing stimulus discriminability; however, scopolamine disrupted CNM correction trial performance much more than did reductions in stimulus discriminability. It is concluded that scopolamine's effects on working memory are not limited to possible effects on stimulus discrimination: Scopolamine may also affect retrieval of response rules from reference memory.

The pattern of cortical projections from the intermediate parts of the magnocellular nucleus basalis in the rat demonstrated by tracing with Phaseolus vulgaris-leucoagglutinin.

The pattern and distribution of the cortical projections from intermediate parts of the cholinergic basal magnocellular nucleus were studied by anterogradely transported Phaseolus vulgaris-leucoagglutinin. This immunocytochemical tracing technique reveals the detailed morphology and distribution of efferents from this intermediate area in the nucleus basalis to the various areas and layers of cortex and amygdala. Major projections with a relatively high density of terminal boutons were found in layers I, II and VI of the frontal cortex, in layers V and VI of parietal and temporal areas, in the entire perirhinal and entorhinal cortices, and in the basolateral nucleus of the amygdaloid body. From the nucleus basalis area studied, few if any projections could be demonstrated to cingulate and occipital cortical regions.