Merits and liabilities of NSAID therapy

The clinical usefulness of nonsteroidal anti-inflammatory drugs (NSAIDs) in antirheumatic therapy is discussed, along with the adverse reaction profile. The authors focus on the recent required gastrointestinal class labeling for NSAIDs as they impact on host population responses. Finally, the risk/benefit and cost/benefit considerations are reviewed.

Hydrogen sulfide exposure alters the amino acid content in developing rat CNS

Hydrogen sulfide is a widespread environmental pollutant that may produce severe effects on the developing nervous system. Putative amino acid neurotransmitter levels in the rat cerebrum and cerebellum were determined to evaluate the effects of exposure to hydrogen sulfide during perinatal development. The levels of aspartate, GABA, glutamate, glycine and taurine were quantitated using high-performance liquid chromatography. With the exception of glycine, all of the amino acids examined were affected by the treatment. On day 21 postnatal, which was the last day of the exposure, aspartate, glutamate and GABA in the cerebrum and aspartate and GABA in the cerebellum were significantly depressed. The observed alterations in the amino acid levels during this critical phase of development may have chronically affected the activity of the neurotransmitters, their receptor sensitivity or their individual target areas. The consequence of one or a combination of such alterations may lead to behavioral and structural abnormalities.

The effects of two anticonvulsants on amino acid levels in the developing rat cerebellum

Two anticonvulsants were administered pre- and postnatally to determine their effects on putative amino acid neurotransmitter levels in the rat cerebellum. The amino acids were quantitated using precolumn fluorescence derivatization and reverse-phase high performance liquid chromatography at various postnatal intervals. Treatment with clonazepam produced an initial depression in levels of most of the amino acids analyised. By three weeks postnatal all the amino acids, with the exception of GABA, had returned to control levels. GABA levels were still depressed five weeks after the cessation of treatment. Phenobarbital treatment produced an initial elevation in the level of GABA. At three weeks postnatal, both GABA and glutamate levels were elevated and remained so at eight weeks postnatal. In conclusion, the data demonstrated that each anticonvulsant produced unique, acute and chronic alterations in the levels of the cerebellar amino acids.

New understandings of NSAID gastropathy

Non-steroidal anti-inflammatory drug (NSAID)-induced gastropathy is a serious public health problem. The United States Food and Drug Administration has recently proposed strong class labelling for NSAIDS, warning of the risk of ulceration, bleeding and perforation associated with their use. The adaptation of the gastric mucosa in response to NSAID intake in volunteers does not seem to occur to the same extent in rheumatic patients. In an ongoing study of patients with osteo- or rheumatoid arthritis, currently in its fourth year, nabumetone has been shown to be relatively gastric sparing when compared with naproxen. Nabumetone is at least as effective as naproxen. Long-term studies are important as treatment of arthritis may involve prolonged use of NSAIDs.

Inhibition of oxytocin-induced but not angiotensin-induced rat uterine contractions following exposure to sodium sulfide

Low concentrations (0.15-15 microM) of sodium sulfide reversibly attenuated the contractile response of the isolated rat uterus to oxytocin without affecting angiotensin II responsiveness. These findings suggest that functionally important disulfide bonds in the rat uterine oxytocin receptor, but not the angiotensin receptor, are sensitive to hydrosulfide ion. Reduction of oxytocin receptors by hydrosulfide ion may be a mechanism by which low levels of H2S delay parturition in rats.

Life stress and lymphocyte alterations among patients with rheumatoid arthritis

The relation between life stress and immune parameters was investigated for 33 female rheumatoid arthritis (RA) patients interviewed during three routine monthly clinic checkups. Life stress from major and minor events, coping efficacy, and self-reported psychological distress were assessed, and immunofluorescence of T-cells and B-cells was performed on the blood drawn during each visit. Small stressful events were positively related to the proportion of circulating B-cells, psychological distress was inversely related to proportion of circulating T-cells, and major life events were associated with lower T-helper/T-suppressor cell ratios.

Prevention of NSAID-induced gastric ulcer with misoprostol: multicentre, double-blind, placebo-controlled trial

A double-blind, placebo-controlled study was carried out to see whether the synthetic E prostaglandin, misoprostol, would prevent gastric ulcer induced by non-steroidal anti-inflammatory drugs (NSAIDs). 420 patients with osteoarthritis and NSAID-associated abdominal pain were studied; they were receiving ibuprofen, piroxicam, or naproxen. Endoscopy was done at entry and after 1, 2, and 3 months of continuous treatment with 100 micrograms or 200 micrograms misoprostol or placebo, given four times daily with meals and at bedtime, concurrently with the NSAID. Abdominal pain was rated independently by patients and physicians. A treatment failure was defined as development of a gastric ulcer. Gastric ulcers (0.3 cm in diameter or greater) occurred less frequently (p less than 0.001) in both misoprostol treatment groups (5.6% 100 micrograms and 1.4% 200 micrograms) than in the placebo group (21.7%). The significant difference in ulcer formation between the placebo and the misoprostol treatment groups remained when comparisons were restricted to ulcers greater than 0.5 cm in diameter (12.3% placebo, 4.2% 100 micrograms misoprostol, and 0.7% 200 micrograms misoprostol). Mild to moderate, self-limiting diarrhoea was the most frequently reported adverse effect attributed to misoprostol. These results provide the first clear indication that NSAID-induced ulcers are preventable.

Evidence that activation of in vitro hippocampal theta rhythm only involves muscarinic receptors

The present study was conducted for two purposes: the first was to evaluate whether activation of nicotinic receptors in the hippocampal formation in vitro (slice) preparation was capable of producing type 2 (atropine-sensitive) theta rhythm. The cholinergic nature and involvement of muscarinic receptors in this type of theta has been previously well documented. The second purpose was to determine whether perfusion of a number of (other) putative neurotransmitters shown to be present in the hippocampal formation could elicit type 1 (atropine-resistant) theta in the slice preparation. Further experiments were conducted to determine if these agents interacted in any manner with cholinergically-induced type 2 theta. Electroencephalic (EEG) theta activity was not induced by nicotine, providing evidence for an exclusive muscarinic receptor involvement in this cholinergically-induced type 2 theta. In addition, theta activity was not elicited by the application of gamma-aminobutyric acid (GABA), glutamate, norepinephrine, dopamine or serotonin. The application of any of these agents did not significantly alter the production of cholinergically-induced theta. These results suggest that type 1 theta originates in regions extrinsic to the hippocampus, or is the result of the interaction of several neurotransmitters on different receptors.

Carbachol-induced EEG 'theta' in hippocampal formation slices: evidence for a third generator of theta in CA3c area

The topography of carbachol-induced EEG theta activity was studied using the hippocampal formation slice preparation. Systematic tracking with electrodes exhibited two amplitude maxima of cholinergic-induced theta, one located in the stratum oriens of the CA1 pyramidal cells and the other in a region of CA3c pyramidal neurons. In addition, mapping experiments demonstrated EEG theta in the CA3a and CA3b cell body layers, but not in the subicular and parasubicular regions, or the ventral blade of the dentate gyrus. Furthermore, transected slice (trans-slice) preparations used in the present study revealed that the CA3c region could generate carbachol-induced theta independently of CA1 and dentate gyrus generator zones and conversely, CA1 and dentate gyrus areas were capable of generating cholinergic-induced theta rhythm independently of the CA3c region. These results provide strong evidence for 3 independent, anatomically separated generators of theta: one located in the stratum oriens of CA1 neurons, a second in the stratum moleculare of the dentate gyrus and a third one in the region of Ca3c cells. In addition, the results support previous in vivo suggestions that theta rhythm can be either elicited or blocked by cholinergic agents acting on sites within the hippocampal formation.

NSAID and gastropathy: a rheumatologist's review

Nonsteroidal antiinflammatory drug (NSAID) use, salicylate and nonsalicylate, is all too commonly associated with gastropathy. The problem is reviewed as significantly impacting upon the success of the most common treatment of most forms of arthritis. Blockade of prostaglandin products by NSAID is recently recognized as a basis for the ultimate failure of adaptive cytoprotection to respond to putative threat and restore the gastric mucosa. A cohort of such patients, based upon risk factors especially noted in elderly women taking longterm high sustained doses of NSAID is identified for purposes of closer clinical monitoring. Issues of prophylaxis, adjustment of arthritis regimens to NSAID gastropathy, and gastroprotective measures are reviewed as strategic responses to this recently recognized and described iatrogenic problem of arthritis management.

Intracellular records of carbachol-induced theta rhythm in hippocampal slices

Intracellular recordings were made in the CA1, CA3 and dentate cell layers prior to, during and after the bath perfusion of 50 microM carbachol on hippocampal slices. Fifty-six percent of the cells in this sample were termed theta (theta)-related, i.e., they exhibited membrane potential oscillations of 5-28 mV and rhythmic spike discharges related to the carbachol-induced extracellular theta-rhythm. The remaining 44% of the cells did not show the above relationships to the extracellular theta-rhythm. Carbachol produced an overall depolarization in all cells, in the range of 10-20 mV. These results demonstrated the cellular basis of carbachol-induced theta in hippocampal slices. This preparation will be a valuable model for studying cellular mechanisms and network properties underlying electroencephalographic activity.

Pharmacologic approaches to musculoskeletal disorders

Pharmacologic considerations of musculoskeletal disease in the elderly involve an appreciation of the pathophysiology of aging as it alters host response to the particular drugs used for these disorders. Treatment of rheumatic conditions is often chronic. Pharmacologic studies of drug handling in the elderly versus the young are often short term and not appropriate to the answers required for sustained therapy in aging individuals with decremental organ system decline, dysfunction, and disease. Where inadequate information exists, the clinical therapist must proceed cautiously on a highly individualized basis in choice of agents, use of those agents at whatever particular dose, and monitoring to ensure safety. Such commitment requires the best of the art as well as the science of medicine. No less is required in the appropriate therapy of these disorders in our elderly population.

Inhalation anaesthetics exhibit pathway-specific and differential actions on hippocampal synaptic responses in vitro

The effects of halothane, isoflurane and enflurane were compared on three CNS excitatory synaptic pathways in vitro, to determine whether selective actions described in vivo result from differential effects on anatomically distinct cortical pathways and neurone populations. Halothane (0.25-1.25 vol%) depressed postsynaptic excitability of CA1 pyramidal neurones in response to activation of stratum radiatum synaptic inputs, and concentration-dependent excitatory (0.25-1.25 vol%) and depressant (1.5-2.0 vol%) actions were observed on dentate granule neurone excitability and perforant path evoked synaptic responses. In contrast, isoflurane increased CA1 neurone excitability (0.25-0.75 vol%) and produced postsynaptic depression of dentate neurones (0.5-4.0 vol%). Enflurane also increased CA1 excitability (0.5-4.0 vol%), but depressed synaptic responses at equivalent concentrations, and produced mixed excitatory (0.25-1.0 vol%) and depressant (1.0-4.0 vol%) effects on dentate synaptic responses. Differential actions were also observed for the three anaesthetics on stratum oriens excitatory inputs to CA1 neurones, and on antidromic responses. A good correlation (r = 0.992) exists between the membrane/buffer partition coefficients of these anaesthetics and their half-maximal concentrations for depression of synaptic responses; however, this correlation does not reflect the different, anaesthetic-specific actions observed. The results indicate that inhalation anaesthetics act at multiple and selective hydrophobic recognition sites which are heterogenously distributed on different synaptic pathways.

Effect of phenobarbital on Purkinje cell growth patterns in the rat cerebellum

The effects of low level phenobarbital administration (18 postcoitus to 21 days postnatal) on Purkinje cell growth and remodeling were studied from 3 to 20 weeks postnatal). The Purkinje cell dendritic trees were analyzed both metrically and topologically using the method of vertex analysis. The total segment length, mean terminal path length, and mean vertex path length were reduced in the treated cells. The pattern of segment frequency as related to equivalent orders was abnormal in the treated cells. The Va/Vb vertex ratios and the levels of trichotomy indicated that the treated cells underwent nonrandom remodeling, unlike the control cells which exhibited dichotomous, random terminal branching. These observations confirm that phenobarbital produces distinct long-term morphologic alterations in Purkinje cells.

The development of carbachol-induced EEG 'theta' examined in hippocampal formation slices

The development of carbachol-induced EEG theta (theta) activity was studied in the CA1 and dentate regions of hippocampal formation slices obtained from neonatal rats (4, 6, 8, 10, 12 and 14 days of age). When perfused with carbachol (50 microM), 4- and 6-day-old hippocampal slices exhibited only short-lasting irregular activity. The initial appearance of carbachol-induced rhythmic waves were observed in slices obtained from 8-day-old rats. From the time that theta appeared at 8 days of age, a steady increase in amplitude and frequency was noted. This observed in vitro developmental pattern of hippocampal theta-rhythm closely resembles the development of theta activity in in vivo preparations.

Naproxen: antirheumatic efficacy and safety in patients with pre-existing gastrointestinal disease

Nonsteroidal antiinflammatory drugs (NSAIDs) effectively reduce pain and inflammation of rheumatoid arthritis (RA). To further refine the appropriate uses of NSAID therapy, NSAIDs have been evaluated for possible gastrotoxicity, particularly in patients who have pre-existing gastrointestinal (GI) disease. In the present study, 58 such RA patients (36 women, 22 men) treated long-term with naproxen were monitored for periods up to 2.5 years to determine if any gastrotoxicity were induced by naproxen. We found an extremely low incidence of fecal occult blood, patient complaints of GI discomfort, complications documented by GI studies, and patient discontinuance of naproxen therapy because of complaints. Studies reported in the medical literature support our observations that naproxen can be well tolerated and is effective as long-term RA treatment when patients who have clinically significant pre-existing GI disease are managed with conventional treatments and appropriate monitoring.

The effects of neomycin on membrane properties and discharge activity of an isolated sensory neuron

The effects of neomycin sulfate were examined upon the discharge activity and electrical membrane properties of an isolated invertebrate sensory neuron, the crayfish stretch receptor neuron. Neomycin depressed cell discharge activity in a concentration-dependent manner over the concentration range of 0.01-1.0 mM. Significant concentration-related increases were observed in the resting membrane potential and the width of the orthodromic action potential. There was a significant concentration-dependent decrease in the fast rising phase of the antidromic action potential. Significant changes also were observed in other electrical properties such as membrane resistance, but these were found not to be concentration related. The most significant change was membrane hyperpolarization, which could account for the depression of cell discharge activity. The observed changes are consistent with a neomycin-induced change in the membrane potassium conductance. It is proposed that the neural effect of neomycin is a selective interaction with the neuronal membrane phospholipids.

Cholinergic theta rhythm in transected hippocampal slices: independent CA1 and dentate generators

The controversy concerning intrahippocampal theta (theta) generators, arising as a result of in vivo investigations, prompted us to record theta-activity from isolated populations of CA1 pyramidal or dentate granule neurons in vitro. In the present study, transected slices (trans-slices) of the hippocampal formation were used to isolate the CA1 area from the dentate gyrus, providing a method for testing the 'two generator' hypothesis. We demonstrated that neurons in both the CA1 area and dentate gyrus could independently generate carbachol-induced (type 2) electroencephalogram (EEG) theta-activity. This activity could be completely blocked by the muscarinic receptor antagonist atropine sulfate but was unaffected by the nicotinic blocker, (+)-tubocurarine. These in vitro results provide the first direct evidence for the two-generator hypothesis and confirm the cholinergic-muscarinic nature of type 2 slow wave theta.