Alendronate interacts with the inhibitory effect of 1,25(OH)2D3 on parathyroid hormone-related protein expression in human osteoblastic cells.

The bisphosphonate alendronate is a potent inhibitor of bone resorption by its direct action on osteoclasts. In addition, there is some data suggesting that alendronate could also inhibit bone resorption indirectly by interacting with osteoblasts. Parathyroid hormone-related protein (PTHrP) produced by osteoblasts and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] are regulators of bone remodeling, which have interrelated actions in these cells. In this study, we assessed whether alendronate can affect PTHrP expression in the presence or absence of 1,25(OH)2D3 in human primary osteoblastic (hOB) cells from trabecular bone. Cell total RNA was isolated, and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) was carried out using human PTHrP-specific primers. PTHrP in the hOB cell-conditioned medium was analyzed by a specific immunoradiometric assay. We found that PTHrP mRNA and secreted PTHrP were maximally inhibited by 10(-8) - 10(-6) M of 1,25(OH)2D3 treatment within 8-72 h in hOB cells. Alendronate (10(-14) - 10(-8) M) modified neither PTHrP mRNA nor PTHrP secretion, although it consistently abrogated the decrease in PTHrP production induced by 1,25(OH)2D3 in these cells. On the other hand, alendronate within the same dose range did not affect either the vitamin D receptor (VDR) mRNA or osteocalcin secretion, with or without 1,25(OH)2D3, in hOB cells. The inhibitory effect of alendronate on the 1,25(OH)2D3-induced decrease in PTHrP in these cells was mimicked by the calcium ionophore A23187 (5 x 10-6 M), while it was eliminated by 5 x 10(-5) M of nifedipine. Furthermore, although alendronate alone failed to affect [Ca2+]i in these cells, it stimulated [Ca2+]i after pretreatment of hOB cells with 10(-8) M of 1,25(OH)2D3, an effect that was abolished by 5 x 10(-5) M of nifedipine. These results show that alendronate disrupts the modulatory effect of 1,25(OH)2D3 on PTHrP production in hOB cells. Our findings indicate that an increase in calcium influx appears to be involved in the mechanism mediating this effect of alendronate.

Down-regulation of L-selectin expression in neutrophils by nonsteroidal anti-inflammatory drugs: role of intracellular ATP concentration.

L-selectin is an adhesion molecule that plays an essential role in the early events of the inflammatory response. Our group has recently described that several nonsteroidal anti-inflammatory drugs (NSAIDs) are able to induce both in vivo and in vitro the shedding of L-selectin in neutrophils through an unknown mechanism. In this work, we have studied potential mechanisms involved in the shedding of L-selectin induced by NSAIDs. This effect of NSAIDs did not involve any detectable intracellular calcium flux. Pretreatment of neutrophils either with Ro 31-8220 and H7, 2 specific inhibitors of protein kinase C (PKC), or with inhibitors of protein tyrosine kinases such as tyrphostin A25 or herbimycin A did not prevent the NSAID-mediated L-selectin shedding. However, the KD-IX-73-4, an inhibitor of L-selectin proteolysis was able to block the effect of NSAIDs on L-selectin expression. Remarkably, NSAIDs caused a variable reduction in the neutrophil intracellular ATP concentration that highly correlated with the differential ability of NSAIDs to trigger L-selectin shedding (r = 0.8, P <.01). In agreement with this finding, azide plus 2-deoxy-D-glucose, 2 metabolic blockers, also induced a rapid L-selectin shedding (65% +/- 8%) without affecting the neutrophil viability, activation, or expression level of other surface molecules with soluble isoforms such as CD16 and CD59. These data indicate that the maintenance of L-selectin on the neutrophil surface requires energy consumption, which suggests that L-selectin is shed in neutrophils by default. Interestingly, NSAIDs seem to cause the shedding of L-selectin, at least in part, through the reduction of the intracellular ATP concentration.

Primary solitary Echinococcosis in cervical spine. Postsurgical successful outcome after long-term albendazole treatment.

STUDY DESIGN: A case report of a young man with isolated cervical hydatidosis treated postoperatively with sustained cyclical albendazole therapy for 9 years of follow-up. OBJECTIVES: To communicate the efficacy and safety of prolonged albendazole treatment in the postoperative management of spinal hydatid disease, and recommend therapeutic regimes for preventing its recurrence. SUMMARY AND BACKGROUND DATA: Bone involvement in hydatid disease is uncommon and the cervical region of the spine is rarely affected. Surgical excision remains the treatment of choice but high rates of postoperative recurrence have highlighted the importance of adjuvant anthelmintic therapy. The selection of the drug(s) and the duration of the medical treatment is still controversial. METHODS: The patient described herein presented with isolated bone lesions, in an unusual cervical location, and without coincidental visceral involvement. Therefore, diagnosis was delayed and surgical debridement was carried out without any preoperative anthelmintic therapy. To prevent late recurrences, therapy with intermittent courses of albendazole has been maintained for nine years and is still ongoing. Response and toxicity related to therapy has been closely monitored by clinical, biochemical and radiological follow up. RESULTS: After surgery the patient has remained asymptomatic without sequelae or evidence of relapses. No clinically relevant side effects has been observed. CONCLUSION: Prolonged albendazole treatment appears to be safe and effective in the prevention of late recurrences after spine hydatidosis surgery. Long-term chemotherapeutic schedules should be considered after surgical excision of spine or bone lesions.

Interference of nonsteroidal antiinflammatory drugs with very late activation antigen 4/vascular cells adhesion molecule 1-mediated lymphocyte-endothelial cell adhesion.

OBJECTIVE: To study the effect of nonsteroidal antiinflammatory drugs (NSAIDs) on the adhesion of peripheral blood lymphocytes (PBL) to activated human umbilical vein endothelial cells (HUVEC) under conditions that resemble blood flow. METHODS: Assays of adhesion of PBL to HUVEC or recombinant vascular cell adhesion molecule 1 (rVCAM-1), intercellular adhesion molecule 1 (ICAM-1), and E-selectin were performed under continuous rotation at 37 degrees C. The phenotype of PBL subpopulations attached was characterized by flow cytometry. Lymphocytes were pretreated with different doses (5-100 microg/ml) of aceclofenac, diclofenac, indomethacin, or piroxicam or with inhibitory monoclonal antibodies (MAb) prior to the adhesion assays. The effect of NSAIDs on lymphocyte adhesion molecules was assessed by flow cytometry. To determine whether NSAIDs interfere with the affinity state of very late activation antigen 4 (VLA-4) integrin, we studied the effect of these drugs on the appearance of a beta1 activation-dependent epitope recognized by the HUTS21 MAb both on human T lymphoblasts and on synovial fluid lymphocytes (SFL). RESULTS: In the flow-resembling model, PBL-HUVEC adhesion was mainly mediated by the VLA-4/ VCAM-1 adhesion pathway. The major PBL subset attached was the CD3+, CD45RO+ memory T cell, with CD49d(high) expression. Aceclofenac, diclofenac, and indomethacin, but not piroxicam, were able to inhibit PBL adhesion to HUVEC or rVCAM-1. However, the quantitative expression of VLA-4 was not affected by treatment of PBL with any of the NSAIDs studied. On T lymphoblasts and SFL, mostly CD45RO+ cells, the expression of the beta1 activation-dependent epitope detected by HUTS21 MAb was significantly decreased by aceclofenac, diclofenac, and indomethacin. CONCLUSION: Some NSAIDs are able to inhibit the adhesion of PBL to HUVEC under conditions that resemble blood flow by interfering with the conformational change in VLA-4 that increases its affinity for VCAM-1.

Hepatic sinusoidal dilatation in rheumatoid arthritis.

In a review of 100 consecutive patients with adult rheumatoid arthritis (RA), clinical evidence of liver disease was absent, whereas minor abnormalities of liver biochemistry, mainly a raised alkaline phosphatase, were present in 32 cases. Liver biopsies were obtained in eight patients; the most striking finding was the presence of sinusoidal dilation in all samples, with a normal central vein and preservation of hepatic architecture. The mechanism of this nonspecific histological change is not known, though it could be speculated to be secondary to a humoral factor related to RA. We conclude that hepatic involvement in adult RA is common but trivial and that routine liver biopsy is not indicated.

Very late activation antigen on synovial fluid T cells from patients with rheumatoid arthritis and other rheumatic diseases.

We used flow cytometry and immunoprecipitation techniques to study the expression of the activation molecules transferrin receptor, interleukin-2 receptor, HLA-DR, and very late activation antigen 1 (VLA-1) on purified T lymphocytes from peripheral blood and synovial fluid of 9 patients with rheumatoid arthritis and 7 patients with other rheumatic diseases. We found a T cell subset bearing VLA-1 in synovial fluid from 8 rheumatoid arthritis patients and 4 patients with other rheumatic diseases. VLA-1 was not found in peripheral blood T lymphocytes from either group.

Antithymocyte globulin in the treatment of gold induced severe aplastic anemia.

Severe aplastic anemia is the most serious complication of chrysotherapy. No treatment for this condition has been demonstrated effective. We report 3 patients with gold induced severe aplastic anemia treated with antithymocyte globulin. Complete marrow recovery was obtained in 1 case and a partial but satisfactory response in the other. All the patients remain alive without requiring blood transfusion after followup of longer than 16 months.