In vivo desensitization of glycogenolysis to Ca2+-mobilizing hormones in rat liver cells

Antithrombotic drug therapy for IgA nephropathy: a meta analysis of randomized controlled trials

BACKGROUND

Antithrombotic agents, including antiplatelet agents, anticoagulants and thrombolysis agents, have been widely used in the management of immunoglobulin A (IgA) nephropathy in Chinese and Japanese populations. To systematically evaluate the effects of antithrombotic agents for IgA nephropathy.

METHODS

Data sources consisted of MEDLINE, EMBASE, the Cochrane Library, Chinese Biomedical Literature Database (CBM), Chinese Science and Technology Periodicals Databases (CNKI) and Japana Centra Revuo Medicina (http://www.jamas.gr.jp) up to April 5, 2011. The quality of the studies was evaluated from the intention to treat analysis and allocation concealment, as well as by the Jadad method. Meta-analyses were performed on the outcomes of proteinuria and renal function.

RESULTS

Six articles met the predetermined inclusion criteria. Antithrombotic agents showed statistically significant effects on proteinuria (p<0.0001) but not on the protection of renal function (p=0.07). The pooled risk ratio for proteinuria was 0.53, [95% confidence intervals (CI): 0.41-0.68; I(2)=0%] and for renal function it was 0.42 (95% CI 0.17-1.06; I(2)=72%). Subgroup analysis showed that dipyridamole was beneficial for proteinuria (p=0.0003) but had no significant effects on protecting renal function. Urokinase had statistically significant effects both on the reduction of proteinuria (p=0.0005) and protecting renal function (p<0.00001) when compared with the control group.

CONCLUSION

Antithrombotic agents had statistically significant effects on the reduction of proteinuria but not on the protection of renal function in patients with IgAN. Urokinase had statistically significant effects both on the reduction of proteinuria and on protecting renal function. Urokinase was shown to be a promising medication and should be investigated further.

Efficacy of methylprednisolone and urokinase pulse therapy combined with or without cyclophosphamide in severe Henoch-Schoenlein nephritis: a clinical and histopathological study

BACKGROUND

There have been few controlled studies of combined therapy with multiple drugs, including immunosuppressives, for severe Henoch-Schoenlein nephritis (HSPN). We evaluated the efficacy of methylprednisolone and urokinase pulse therapy combined with cyclophosphamide for patients with HSPN of at least grade IVb.

METHODS

We studied 37 patients who had been diagnosed with HSPN of at least grade IVb. Of them, 20 (Group A) were treated with methylprednisolone and urokinase pulse therapy, and 17 (Group B) were treated with methylprednisolone and urokinase pulse therapy combined with cyclophophamide. We analysed the clinical features, laboratory and pathological findings of the two groups retrospectively.

RESULTS

After 6 months of treatment, mean urinary protein excretion in Group B had significantly decreased compared with Group A, and the activity index of both groups at the second biopsy was lower than that at the first. Furthermore, at the second biopsy, the chronicity index of Group B was lower than that of Group A. Four patients of Group A but none of Group B had persistent nephropathy (P<0.05).

CONCLUSIONS

Our study suggests that methylprednisolone and urokinase pulse therapy combined with cyclophosphamide is useful for patients with severe HSPN.

Effects of co-administration of urokinase and benazepril on severe IgA nephropathy

BACKGROUND

The availability of treatment for IgA nephropathy (IgAN) is limited. Method. A prospective randomized controlled clinical trial was performed to evaluate the effects of therapy with urokinase (UK) and benazepril (BZ, an angiotensin-converting enzyme inhibitor) or BZ alone on severe IgAN. We divided 71 cases of IgAN, Lee's grade >/=III and with fibrinogen deposits, into two groups to be treated for 12 months with either UK + BZ or BZ alone.

RESULTS

There was no significant difference between the two groups in baseline clinical and histopathological data. After 12 months of treatment, 25 of 35 patients (71.4%) in the UK + BZ group and 16 of 36 (44.4%) in the BZ-alone group had a >/=50% decrease in 24-h urinary protein excretion compared with the baseline (chi(2) test, P<0.05). Proteinuria significantly decreased at 6 and 12 months of treatment in both groups compared with baseline (P<0.01 in the UK + BZ group, P<0.05 in the BZ group), and the therapeutic efficiency of UK + BZ was better than that of BZ alone (P<0.05 at 6 and 12 months). The endogenous creatinine clearance rate (Ccr) was stable in the UK + BZ group, while Ccr declined significantly at 6 and 12 months in the BZ-alone group compared with baseline (P<0.05, respectively). The Ccrs of the two groups at 12 months of treatment were statistically different (P<0.05).

CONCLUSIONS

Combined therapy with UK and BZ was more effective than with BZ alone in reducing proteinuria and protecting renal function in patients with severe IgAN.

Effect of receptor density on the receptor-effector coupling: use of cloned and stably expressed alpha 1B-adrenoceptors in CHO cells

Using Chinese hamster ovary cells stably expressing alpha 1B-adrenoceptor as a model, we investigated whether the changes in receptor density may influence the receptor-effector coupling relationship. Among the transfected cells, two clones which showed similar pharmacological properties but markedly differed in receptor density (Bmax were 1600 and 110,000 sites/cell, respectively), were examined. The phenoxybenzamine inactivation method showed that the alpha 1B-adrenoceptor occupancy and transients of cytosolic Ca2+ concentration ([Ca2+]i) response relationship was markedly nonlinear but similar in the two cell lines. The dose-response relationship for norepinephrine-induced [Ca2+]i response showed an increase in maximum effect with no change in agonist potency, and the increase in maximum effect was disproportionate to the difference in receptor density. The results indicate that the classical model of drug-receptor action cannot appropriately describe the coupling of alpha 1B-adrenoceptor to [Ca2+]i response in the single receptor expressing system.

Different mechanisms of homologous and heterologous desensitization of thrombin-induced endothelial prostacyclin production

Several workers have described desensitization of endothelial prostacyclin production but conflicting evidence has been published regarding the mechanism of desensitization, whether it is homologous (agonist specific) or heterologous, and whether inactivation of cyclooxygenase is involved. The purpose of the present study was to determine the relation between the intensity of a first thrombin stimulus and the subsequent response to a repeat thrombin, histamine, ionophore A23187 or aluminium fluoride (AlF4) stimulation and to determine possible targets of desensitization. Following thrombin stimulation of confluent cultured human umbilical vein endothelial cells (HUVEC) only homologous desensitization of inositol phosphate production was observed. Both homologous and heterologous desensitization of arachidonic acid release and prostacyclin production occurred, the latter towards both histamine and the ionophore A23187. For any given dose of the first stimulant there was a much greater effect on the homologous response than on the heterologous response. These differences suggest different mechanisms. The homologous desensitization probably involves the receptor whereas the present results suggest that the target of heterologous desensitization is distal to calcium mobilization in the signal transduction pathway. The possibilities include decreased activity of phospholipase A2 or a decreased pool of accessible arachidonic acid.