Biomedical subjects
J P Larbre
Publications and source records attributed to J P Larbre.
[Corticosteroids].
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A randomized trial of testosterone therapy in males with rheumatoid arthritis.
Thirty-five male patients, aged 34-79 yr, with definite rheumatoid arthritis (RA) were recruited from out-patient clinics and randomized to receive monthly injections of testosterone enanthate 250 mg or placebo as an adjunct therapy for 9 months. Endpoints included disease activity parameters and bone mineral density (BMD). At baseline, there were negative correlations between the ESR and serum testosterone (r = -0.42, P < 0.01) and BMD (hip, r = -0.65, P < 0.01). A total of 29.6% of all patients had at least one vertebral fracture, most having multiple fractures. Back pain, however, was not more prevalent in fracture patients (55% vs 50%). Disease activity was significantly higher in the fracture group (joint score P < 0.05, rheumatoid factor P < 0.01). Thirty patients completed the trial, 15 receiving testosterone and 15 receiving placebo. There were significant rises in serum testosterone, dihydrotestosterone and oestradiol in the treatment group. There was no significant effect of treatment on disease activity overall, five patients receiving testosterone underwent a "flare'. Differences in mean BMD following testosterone or placebo were non-significant (spine: +1.2% vs -1.1%; femur: -0.3% vs +0.3%). There was no suggestion of a positive effect of testosterone on disease activity in men with RA.
Upper lumbar disk herniations.
Specific features of upper lumbar disk herniations are reviewed based on data from the literature and from a retrospective study of 24 cases treated surgically between 1982 and 1994 (seven at L1-L2 and 17 at L2-L3). Clinical manifestations are polymorphic, misleading (abdominogenital pain suggestive of a visceral or psychogenic condition, meralgia paresthetica, isolated sciatica; femoral neuralgia is uncommon) and sometimes severe (five cases of cauda equina syndrome in our study group). The diagnostic usefulness of imaging studies (radiography, myelography, computed tomography, magnetic resonance imaging) and results of surgery are discussed. The risk of misdiagnosis and the encouraging results of surgery are emphasized.
Direct degradation of articular cartilage by rheumatoid synovial fluid: contribution of proteolytic enzymes.
OBJECTIVE: To test the effects of synovial fluids (SF) on human cartilage in an in vitro model. METHODS: Freshly collected SF were incubated with cryostat sections of articular cartilage, and glycosaminoglycan (GAG) loss determined by microdensitometry after alcian blue staining. RESULTS: Of 20 rheumatoid SF, 11 induced significant GAG loss compared with only 3 out of 15 osteoarthritic SF. The effect of rheumatoid fluids appeared to be related to disease activity. GAG loss was partially prevented by a broad spectrum serine protease inhibitor and a specific elastase inhibitor. Cartilage degrading activity was lost on storage which may explain why it has not been widely reported before. CONCLUSION: Rheumatoid SF can directly degrade cartilage through the action of proteases. There is an involvement of serine proteases, elastase in particular.
Sex differences in inflammation induced cartilage damage in rodents. The influence of sex steroids.
OBJECTIVE: To investigate sex differences in granulomatous inflammation and its effects upon articular cartilage and to assess the potential role of sex steroids in the process. METHODS: The cotton-pellet cartilage implant model was used with male and female mice in the presence and absence of gonadectomy and hormone replacement. The effects of granulomatous tissue upon articular cartilage was assessed and tissue content of interleukin 1 (IL-1) was determined. The expression of sex hormone receptors in inflammatory tissue was investigated by immunocytochemistry. RESULTS: Female mice showed a higher ability than males to degrade cartilage irrespective of the sex of the cartilage implanted. Gonadectomy resulted in a significant acceleration of cartilage damage in both sexes, which was reverted by estrogen replacement in females and androgen replacement in males. Female granulomata had significantly higher IL-1 content than those from males. Gonadectomy was associated with an increased IL-1 content in males but not in females, the effects being abolished by androgen replacement in males. Estrogen and androgen receptors were identified in inflammatory cells from the granulomatous tissue. CONCLUSION: Our data demonstrate that sex hormones affect inflammation induced cartilage degradation in male and female mice probably through the modulation of cytokine production and release in the granulomatous tissue. Further investigation on the effects of sex steroids in inflammation induced cartilage degradation may help elucidate their pathogenic role and therapeutic potential in human disease.
Arrhythmogenicity of antiarrhythmic drugs and intraventricular conduction disorders: possible aggravation by myocardial ischemia--study in the porcine in situ heart.
The effects of three antiarrhythmic drugs were investigated in anesthetized, open-chest pigs, in a left ventricular area, under pacing at a constant high rate (180 beats/min), in the absence and presence of ischemia. Ischemia was produced by transient complete occlusion of the left anterior descending coronary artery near its origin. In addition to the surface electrocardiogram, conduction time and monophasic action potential were recorded in the contractile fibers. In the absence of ischemia, intravenous flecainide and propafenone 2.5 mg/kg, and intravenous cibenzoline 2.0 mg/kg considerably lengthened conduction time (by 50-90%) but had no significant effect on the monophasic action potential duration. Consequently, the cited antiarrhythmic drugs enhance the prolongation of conduction time by 60% but do not limit the 30% shortening of the monophasic action potential caused by ischemia. Contrary to what was expected, they largely reduced the time to onset of the fibrillation due to ischemia from about 120 to 25 seconds. Thus, they manifested profibrillatory properties (more pronounced than those of other antiarrhythmic drugs of class I), which might be explained by their potent action on depolarization.
Cartilage degradation by polymorphonuclear leucocytes: in vitro assessment of the pathogenic mechanisms.
Polymorphonuclear leucocytes (PMNs), which predominate in inflammatory synovial fluid, can degrade cartilage. This was measured by a novel in vitro model; PMNs were incubated for up to one hour with 2 or 3 microns sections of cartilage and the glycosaminoglycan loss determined by microdensitometry after alcian blue staining. Glycosaminoglycan loss could be as a result of damage from reactive oxygen species, proteolytic enzymes, or a combination of the two. The relative contributions of these mechanisms were evaluated using selective inhibitors. The results show that activated PMNs will degrade cartilage and that this degradation is due to proteolytic enzymes and not reactive oxygen species. There is a specificity involving elastase but not other serine proteases. It is suggested that enzyme inhibition may play a part in reducing PMN mediated cartilage damage.
Protective effect of androgens against inflammation induced cartilage degradation in male rodents.
OBJECTIVES: Rheumatoid arthritis (RA) is a disease which predominantly affects women. Interestingly, low serum androgen levels and clinical improvement with androgen replacement have been reported in male patients. The aetiopathogenic role of sex hormones in arthritis and their potential long term effects on joint destruction and disability remains unclear, however. This study was designed to investigate the potential influence of sex hormones on inflammation induced cartilage degradation in male rodents. METHODS: An in vivo model of cotton wrapped cartilage implants was used to assess the effects of androgen, oestradiol, and progesterone on inflammation induced cartilage degradation, and in vitro techniques were used to investigate the direct actions on cartilage metabolism and cytokine production in male animals. RESULTS: Orchidectomy resulted in accelerated cartilage damage which was reversed by replacement of physiological levels of androgens. Granulomatous tissue from castrated male rodents produced higher amounts of interleukin 1. Sex hormones reduced spontaneous proteoglycan loss in vitro but did not interfere with the effects of interleukin 1 on cultured cartilage. CONCLUSIONS: Androgens appear to protect cartilage from inflammation induced breakdown in male animals. These results support a pathogenic role for hypoandrogenism in rheumatoid arthritis and suggest that long term androgen replacement may help prevent joint damage and disability.
Medical treatment of common cervicobrachial neuralgia.
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Cerebrospinal fluid dynamics in the tardive cauda equina syndrome of ankylosing spondylitis.
Typical cauda equina syndrome secondary to long-standing ankylosing spondylitis is reported in a 63-year-old man. Radionuclide cisternography demonstrated a resorption defect of cerebrospinal fluid in the enlarged lumbosacral dural sac. After transient symptomatic improvement with acetazolamide, a lumboperitoneal shunt was placed. The rate of cerebrospinal fluid, isotope resorption became normal. In the 5 years of follow-up, partial remission has been observed.
Rheumatoid metatarsus. The original evolution of the first metatarsal.
Three hundred and eight unselected rheumatoid feet underwent a weight-bearing X-ray examination. If the malformations of the forefoot studied here present a statistical association, the primus metatarsus adductus is closely connected with tarsal arthritis and flattened foot but does not depend on the duration of the disease. The spread forefoot is indeed related to the duration of the disease and the presence of a metatarsal erosion at the foot level, but is not affected by the lesions of the midfoot. It appears then that an early orthopaedic treatment should be prescribed, once the first signs of involvement of the first ray or pronounced pronation of the hindfoot are noticed; it must affect the hindfoot, the midfoot and the first ray which progress together.
Protection against ischaemic ventricular fibrillation by blocking agents of myocardial cell calcium influx. Electrophysiological study in the pig in situ heart.
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Kaposi's sarcoma in a patient with rheumatoid arthritis possible responsibility of captopril in the development of lesions.
Kaposi's sarcoma appeared 8 months after the start of captopril treatment in a 70-year-old woman with rheumatoid arthritis. A marked reduction of cutaneous and gastric lesions occurred when captopril was stopped. These findings are compared to immunosuppressive drug induced forms of Kaposi's sarcoma.
[Arrhythmogenic risk of antiarrhythmic drugs: study with class Ic drugs during myocardial ischemia].
The effects of three Ic antiarrhythmic drugs were investigated in anaesthetized, open-chest pigs, in a left ventricular area under pacing at constant high (180/min) rate, outside and during an ischaemia produced by temporary complete occlusion of the left anterior descending coronary artery, 1-1.5 cm from its origin. In addition to surface ECG, conduction time and monophasic action potential were recorded in the contractile fibres. Measurement of effective refractory period was added outside the periods of ischaemia. In this event, flecainide and propafenone, in 2.5 mg/kg dose, and cibenzoline, in 2.0 mg/kg dose, i.v. injected, lengthened considerably (50 to 90%) conduction time, but did not affect or hardly affected monophasic action potential and effective refractory period. During ischaemia, they did not hinder the abbreviation of monophasic action potential (30%) and reduced to a large extent (about 120 to 25 s) the onset time of fibrillation. The profibrillatory effect of Ic antiarrhythmic drugs, certainly more pronounced than those of other antiarrhythmic drugs, might be explained by their potent action on depolarization of the contractile fibres coincident with an almost total absence of action on repolarization.
Antinuclear antibodies during pyrithioxine treatment.
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[Cervical spondylodiscitis and rheumatoid polyarthritis].
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[Bullous toxic dermatitis due to disulfiram. Apropos of a case].
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