Characterisation of cyclooxygenase 1 and 2 expression in mouse resident peritoneal macrophages in vitro; interactions of non steroidal anti-inflammatory drugs with COX2.

Resident peritoneal macrophages exposed to inflammatory stimuli (zymosan, lipopolysaccharide (LPS)) represent a widely used model for studying arachidonic acid metabolism and for screening of prostaglandin (PG) synthesis inhibitors. In the present study, cyclooxygenase 1 (COX1) was shown constitutively expressed in mouse adherent and non-adherent macrophages whereas expression of COX2 was observed only in adherent cells, even when cultured in minimal conditions (Ca-, Mg- and serum-free medium). The COX2 expression was amplified by arachidonic acid cascade stimulating agents (Ca, Mg, zymosan) and by LPS in a time-dependant manner; PGE2 by itself amplified LPS-induced COX2 expression. In well-defined experimental conditions of COX2 expression (LPS-stimulated adherent macrophages), we studied specific interactions of some representative anti-inflammatory drugs with COX2 enzymatic activity and expression. By contrast with dexamethasone, which reduced PGE2 release together with a strong reduction of COX2 expression (protein and mRNA), non steroidal anti-inflammatory drugs (NSAIDs) reduced PGE2 synthesis without any effect at the COX2 mRNA level. This reduction of PGE2 production by NSAIDs resulted from either an exclusive enzymatic inhibition (aspirin, NS398, 6-Methoxy naphtyl acetic acid) or an enzymatic inhibition associated with a slight decrease of COX2 protein level (indomethacin). For paracetamol and salicylic acid, two weak inhibitors of COX enzymatic activity, reduction of PGE2 synthesis appeared to be related to reduced level of COX2. These findings show that the macrophage can be used as a cellular model to study specifically COX1 and COX2. In this cell type, COX2 expression is dependent on adhesion, enhanced by stimulation of arachidonic acid metabolism, and auto amplified by PGE2. Furthermore, the results indicate that known NSAIDs differ in their interaction with cyclooxygenase, being able to inhibit either COX2 enzymatic activity, and/or COX2 expression. However, further studies are required to determine the mechanism and the role of COX2 expression during inflammation in vivo, and to define more precisely the best target for new potent and safe NSAIDs.

Bone morphometric changes in adjuvant-induced polyarthritic osteopenia in rats: evidence for an early bone formation defect.

Adjuvant polyarthritis (AP) in rats is known to result in extensive bone loss. This study investigates the mechanisms responsible for the early trabecular osteopenia evaluated at a single point in time--2 weeks after adjuvant injection--in the hindpaw of female Lewis rats using biochemical and histomorphometric methods. At this early point in time, the inflammation was generalized (inflammatory score, 20; albumin/globulin, -80% versus control). Histomorphometric analysis of the noninjected femur showed that the trabecular bone volume was significantly decreased (-28% versus control) in both proximal and distal parts, and the femur growth rate was unaffected. The trabecular osteopenia was associated with a 90% decrease in osteoid surface and a concomitant thinning (-19%) of the trabeculae. Both the double-fluorescence-labeled surface and the osteoblast surface were also markedly decreased (-75%). In addition, the mineral apposition rate was reduced (-50%) and the bone formation rate was decreased by as much as 90%. The trabecular bone volume was decreased in relation with the extent of double-fluorescence labeling (r = 0.38, p = 0.03) and bone formation rate (r = 0.42, p = 0.01), suggesting that the generalized osteopenia resulted from the reduced bone formation. This was associated with a 26% reduction in plasma osteocalcin. Neither the osteoclast surface nor the number of osteoclasts was consistently affected. However, urinary hydroxyproline was increased by 100-200%, which likely reflected the cartilage and bone destruction at the site of injection. The present data show that the early extensive osteopenia observed 2 weeks after AP induction in rats results from defective bone formation with unchanged bone resorption. The role of cytokines in such an inhibitory effect on bone formation remains to be determined.

1,3-Diaryl-4,5,6,7-tetrahydro-2H-isoindole derivatives: a new series of potent and selective COX-2 inhibitors in which a sulfonyl group is not a structural requisite.

Novel tetrahydro-2H-isoindoles have been prepared and evaluated as inhibitors of the COX-2 isoenzyme. A 1,3-diaryl substitution on the central polycyclic ring system and absence of a sulfonyl moiety are the two structural features of this chemical series. A short and easy synthetic pathway produced several derivatives which were shown to be potent and selective COX-2 vs COX-1 inhibitors (IC(50) = 0. 6-100 nM for COX-2, 100->1000 nM for COX-1). Structural modifications established that a bicyclic ring appended to the pyrrole nucleus and 4,4'-difluoro substitution on the phenyl rings were optimal for high inhibitory potency. Activity was confirmed in the human whole blood assay and subsequently in the murine air-pouch model in which in vivo PGE2 inhibitory activity was evaluated with respect to gastric tolerance (ED(50) for inhibition of exudate PGE2 of 3 mg/kg and gastric PGE2 of 20 mg/kg). Gastric tolerance was further assessed after administration to mice of high doses (up to 400 mg/kg) of the inhibitors by measurement of gastric damage. This panel of studies allowed selection of a number of tetrahydro-2H-isoindoles which were compared in the adjuvant-induced arthritis model. Compounds 32 and 37 showed the most potent activity with ED(50) values for edema inhibition in the noninjected paw of 0. 35 and 0.15 mg/kg/day, respectively, after oral administration. In addition, this interesting antiinflammatory profile was accompanied by a protective effect against arthritis-induced osteopenia, the decrease being 50% with a dose of 0.25 mg/kg/day.

[Pneumonia and submaxillary cellulitis caused by B group Streptococcus in an infant]. / Pneumopathie et cellulite sous-maxillaire à streptocoque B chez un nourrisson.

The association of pneumonia and submandibular cellulitis in the case of group B streptococcal LOD (Late Onset Disease) is rare. Concerning the possible nosocomial infection of a 31/2 months infant the authors compare the pulmonary disease with that of the EOD (Early Onset Disease) and like other authors recommend considering GBS as the main cause of any cellulitis for an infant under 4 months.

[The Vater association in a newborn infant of a diabetic mother]. / L'association VATER chez un nouveau-né de mère diabétique.

Concerning the case history of an infant of diabetic mother, the authors analyse the possible relationship between a VATER association and a poorly controlled diabetes mellitus in the early weeks of pregnancy. Caudal regression syndrome, the most frequently observed malformation noted in infants of diabetic mothers and VATER association are the results of an "AXIAL MESODERMAL DYSPLASIA". Furthermore, the factors causing VATER association occur before the seventh week of pregnancy like those responsible for the anomalies observed in infants of diabetic mothers. It is possible that a poorly controlled diabetes mellitus before conception and in the early weeks of pregnancy could favour the appearance of VATER association.

[Supraventricular tachycardia and fetal edema. Apropos of 2 cases]. / Tachycardie supraventriculaire et anasarque foetales. A propos de deux observations.

Two cases of supraventricular tachycardia responsible for hydrops fetalis emphasize the interest of an antenatal echocardiography. The systematic use of this technique will increase the frequency of diagnosis of this etiology in other cases where the prognosis is less favorable. The in utero treatment of this rhythmic disorder consists in administering Digoxin to the mother and the newborn child must receive excellent care from the moment of the birth.

[Congenital toxoplasmosis in the Alpes-Maritimes region. Apropos of 26 cases observed between 1984 and 1990]. / La toxoplasmose congénitale dans les Alpes-Maritimes. A propos de 26 cas observés entre 1984 et 1990.

Twenty-six cases of congenital toxoplasmosis observed in the department of Alpes Maritimes (Chief Town: Nice) between 1984 and 1990 are reported. All affected children were treated by pyrimethamine and sulfonamide as soon as the diagnosis was established. None of them exhibited serious sequellae. In most cases (58%) there were no clinical manifestations in agreement with other reports. Benign manifestations were observed in 10 cases (38%): 4 chorioretinitis; 4 intracranial calcifications: 1 febrile seizure; 7 hyperproteinorachias: 3 isolated and 4 associated with other signs. In 3 cases, secondary lesions appeared during the treatment period. This confirms the need for active therapeutic research in order to decrease the risk of late ocular complication which is the major problem of the disease.

Evaluation and comparison of urinary pyridinium crosslinks in two rat models of bone loss--ovariectomy and adjuvant polyarthritis--using a new automated HPLC method.

A specific HPLC system was developed to assess urinary excretion of collagen crosslinks (pyridinoline (Pyr) and deoxypyridinoline (D.Pyr)) in two models of osteopenia in rats, ovariectomy and adjuvant polyarthritis. The sensitivity of this method was in the picomolar range. In ovariectomized rats, a specific model of bone resorption, Pyr and D.Pyr levels rose early, reaching a peak 2 weeks after surgery. Both levels remained raised during the whole observation period (6 weeks) with no change in the Pyr/D.Pyr ratio. So, in this high bone turnover model, hyperresorption is reflected by the parallel increase of both crosslinks resulting in a significant decrease of bone mineral density (BMD) at 6 weeks (-7.3% vs. control). In polyarthritic rats, in the 2 post-adjuvant weeks, Pyr levels increased in parallel with inflammatory parameters, whereas D.Pyr levels remained unchanged. This is in agreement with our previous report that at the end of the 2nd week after adjuvant there is no change in bone resorption. From the 3rd week, both Pyr and D.Pyr increased. The Pyr/D.Pyr ratio was always significantly higher in polyarthritic rats. These results suggest that the early increase of Pyr level reflects non-osseous collagen breakdown and that bone resorption occurs at a later stage when D.Pyr rises, leading to a dramatic decrease of BMD at 4 weeks (-17.7% vs. control). Taken together, our results suggest that in rat as in human, urinary Pyr is a marker of bone and cartilage breakdown, whereas D.Pyr is a specific marker of bone loss. This automated method described may constitute a very useful tool to evaluate bone and/or cartilage breakdown in rats and for the assessment of protective treatments.