Oral zolmitriptan is effective in the acute treatment of cluster headache.

OBJECTIVE: To evaluate the efficacy and tolerability of oral zolmitriptan 5 mg and 10 mg and placebo in cluster headache. METHODS: A multicenter, double-blind, randomized, three-period, crossover, outpatient study. Adult patients received placebo and zolmitriptan 5 mg and 10 mg orally for the acute treatment of episodic or chronic cluster headache. Headache intensity was rated by a five-point scale: none, mild, moderate, severe, or very severe. Patients only treated moderate to very severe headaches. The primary efficacy measure was headache response (two-point or greater reduction from baseline in the cluster headache rating scale) at 30 minutes. Secondary efficacy measures included proportion of patients with initial headache relief within 15 and 30 minutes, mild or no pain at 30 minutes, meaningful headache relief, and use of escape medication. RESULTS: A total of 124 patients took at least one dose of study medication, with 73% having episodic and 27% chronic cluster headache. For the primary endpoint, there was a treatment-by-cluster-headache-type interaction (p = 0.0453). Therefore, results are presented separately for chronic and episodic cluster headache. In patients with episodic cluster headache, the difference between zolmitriptan 10 mg and placebo at 30 minutes reached significance (47% versus 29%; p = 0.02). Mild or no pain at 30 minutes was reported by 60%, 57%, and 42% patients treated with zolmitriptan 10 mg, zolmitriptan 5 mg, and placebo (both p

Stimulation and inhibition of bone formation: use of peripheral quantitative computed tomography in the mouse in vivo.

The purpose of this study was to assess peripheral quantitative computed tomography (pQCT) imaging for measurement of volumetric bone mineral density (BMD) in vivo in mouse tibia following ovariectomy, and following treatment with 17 beta-oestradiol (E2). Two studies were undertaken. In study 1, three groups (n = 10) of mature mice were ovariectomized (OVX) or sham operated (SHAM); one of the OVX groups was dosed weekly with E2 (OVX.E2). Images of the proximal tibia were acquired on the day of surgery and at intervals following surgery until week 6. In study 2, four groups (OVX, SHAM, OVX.E2 and a SHAM group dosed with E2, SHAM.E2) of immature mice (n = 10) were imaged weekly up to 10 weeks post-surgery. Precision of pQCT for measurement of total (trabecular plus cortical) BMD was 2.4%, trabecular 5.2% and cortical 2.6%. In mature animals, significantly slower net bone formation was seen in OVX compared with SHAM animals using paired analysis with each animal as its own control. Group analysis detected no significant difference in BMD between SHAM and OVX at any time point. In immature animals, using paired analysis, with each animal as its own control, a significant difference between SHAM and OVX animals was detectable 3 weeks post-surgery (P < 0.05). As in study 1, group analysis of total BMD failed to detect any significant difference between SHAM and OVX at any time point. Treatment with E2 caused an easily-detected increase in BMD and led to osteopetrosis in both groups. The statistical power of this technique is adequate for testing antiresorptive or bone-forming therapies in the mouse.

Bone mineral density and composition in rat pregnancy: effects of streptozotocin-induced diabetes mellitus and insulin replacement.

A disturbed calcium homeostasis characterizes diabetic pregnancy. This study documents changes in bone mineral composition in diabetic pregnant rats and examines the effect of insulin replacement. Control pregnant (CP), diabetic pregnant (DP) and insulin-treated DP (DPi) rats were assessed for femoral calcium and magnesium content, bone mineral density (BMD) and the ratio of hypertrophic to maturing and proliferative cells in the femoral growth plate. DP rats showed a significantly (P < 0.01) lower body weight, femoral weight and length than CP rats. Femoral calcium and magnesium content was also significantly (P < 0.05) lower in DP rats, as was ash weight. When calcium and magnesium were normalized for ash weight no significant differences were apparent. A significantly (P < 0.05) lower total BMD at the distal femur was seen in DP rats. This comprised a significantly (P < 0.01) lower trabecular BMD with no significant change in cortical BMD. A significantly (P < 0.05) higher ratio of hypertrophic to maturing and proliferative cells of the femoral growth plate was evident in DP animals. DPi rats showed normal blood glucose concentrations and femoral growth plate histology. DPi rats also showed normal femoral weight and length but only partially restored femoral ash weight and mineral content. Insulin failed to normalize total or trabecular BMD. Diabetes mellitus clearly has a marked effect on bone growth and mineral content in pregnancy which may be relevant to overall calcium homeostasis. The lower bone growth, bone calcium content and trabecular BMD may be unfortunate consequences of the marked hypercalciuria reported elsewhere in diabetes and may serve to maintain normocalcaemia in the disease.

Effects of an inhibitor of cathepsin L on bone resorption in thyroparathyroidectomized and ovariectomized rats.

The process of bone resorption by osteoclasts involves the dissolution of mineral salts and enzymatic degradation of the mainly collagenous extracellular matrix. Cysteine proteinases, which can efficiently degrade collagen at acidic pH, have been suggested to play an important role in the bone resorptive process. The cysteine proteinase cathepsin L is secreted by osteoclasts, and inhibitors of this enzyme can prevent bone resorption in vitro. The activity of acetyl-leu-leu-norleucinol (ALLN), a selective inhibitor of cathepsin L, was investigated in two models of bone resorption in vivo. In the first study, the ability of ALLN to inhibit bone resorption was investigated in Ro-13-6298 (arotinoid)-treated thyroparathyroidectomized (TPTX) rats. ALLN [100 mg/kg, intraperitoneally (i.p.)] inhibited hypercalcemia by 62.8% acutely (p < 0.001), compared to 94.9% (p < 0.001) inhibition by salmon calcitonin (sCT) (10 IU/kg, subcutaneously). In rats treated for 3 days with ALLN, arotinoid-induced reduction in cortical bone mineral density measured by peripheral quantitative computed tomography (pQCT) was inhibited by 86.4% (p < 0.05) in rats treated with ALLN 100 mg/kg, i.p., and by 82% in rats treated with 50 mg/kg, i.p. (p < 0.05). In a second study, the efficacy of ALLN was tested in a longitudinal study in ovariectomized (ovx) rats. Bone loss, measured by pQCT, was unaffected by treatment with ALLN. The bisphosphonate alendronate, however, inhibited bone loss in this model. These data demonstrate the ability of a cathepsin L inhibitor to inhibit bone resorption in arotinoid-treated TPTX rats, a process which may be dependent on the activity of cathepsin L-like cysteine proteinases. In contrast to its effects in TPTX rats, ALLN had no inhibitory activity on bone resorption in ovx rats. It is possible that in chronic bone resorption in ovx rats, the activity of other enzymes such as cathepsins OC-2 or K allows the process of resorption to continue even when cathepsin L is inhibited by ALLN. Further studies are required to determine why the activity of ALLN varies between different animal models. These data indicate that there may be variations in the effects of drugs in different animal models of bone resorption which should be considered when investigating novel antiresorptive therapies.

Regional analysis of bone mineral density in the distal femur and proximal tibia using peripheral quantitative computed tomography in the rat In vivo.

The use of peripheral quantitative computed tomography (pQCT) was investigated for the measurement of volumetric bone mineral density (BMD) in mg x cm-3. Two studies were undertaken. In the first study, the precision of pQCT in vivo and ex vivo was tested at 14 weeks postovariectomy (OVX). In the second study, the efficacy of a standard antiresorptive treatment, 17beta-estradiol (E2), was tested 6 weeks post-OVX. The precision for total (compact plus trabecular) BMD was 1.3-1.9%, and that for trabecular BMD was 2.4-2. 7%. There was excellent agreement between trabecular BMD measurements in vivo and ex vivo (r = 0.91). Significant reductions in trabecular BMD were observed in vivo at 14 and 6 weeks following ovariectomy in the femur, in each study. The loss of trabecular BMD depended on slice location, and varied from 0 to 22% at 6 weeks, and from 0 to 26% at 14 weeks (P < 0.001, at the affected locations). The antiresorptive effect of treatment was demonstrated in the 6-week study: there was no significant difference in BMD between sham-operated and E2-treated OVX rats.

Inhibition of aldose reductase: 13C NMR studies in isolated peripheral nerve.

We report 13C NMR measurements of the flux through aldose reductase in isolated rat sciatic nerve, and its inhibition by an aldose reductase inhibitor of the sulphonylnitromethane class. [1-13C] galactose was used as substrate, and the rate of production of [1-13C] dulcitol was measured. Quantitation required the use both of internal extracellular, and external, standards. The mean net forward flux (+/- SD) was 20 +/- 11 nmol/(mL nerve water)/min (n = 10). In the presence of the inhibitor, flux was reduced significantly (p < 0.001) to 13% of control. Since dulcitol is symmetrical, an estimate of the backward flux, to [6-13C] galactose, is also possible; under our conditions, this was negligible.