Interactions between clarithromycin and digoxin in patients with end-stage renal disease

OBJECTIVE: To report a significant increase in the serum levels of digoxin associated with the use of clarithromycin in six patients undergoing renal replacement therapy. CASE SUMMARY: All six patients were males with end-stage renal disease and in need of renal replacement therapy. Four patients were anuric. The mean age was 78.8 +/- 5.8 (66-83) years. All patients except one, who was treated by hemofiltration, were treated by hemodialysis. All patients except one, who had been treated with metildigoxin (0.35 mg/week), were also taking digoxin (0.375 mg/week). Clarithromycin was administered at a dose of 200-400 mg/day for the treatment of bronchitis in all patients. The concomitant administration of clarithromycin increased serum digoxin levels from 1.8-4.0-fold in all cases. In two of six cases, a high probability of digoxin intoxication and suspicion of digoxin intoxication was evident. In three of six cases, serum digoxin levels increased within 12 days after the co-administration of clarithromycin, while in the other three cases, serum digoxin levels were increased 53-190 days after the administration of clarithromycin. CONCLUSION: The simultaneous administration of clarithromycin caused an increase in digoxin levels in six patients undergoing renal replacement therapy. The increase in the serum digoxin can be attributed to the inhibition of P-glycoprotein in the intestine and/or bile capillary rather than the kidney by clarithromycin since renal function was dramatically impaired, and four of the patients were anuric. The issue of why serum digoxin levels were increased so late in three patients undergoing renal replacement is unclear. However, this interaction seemed to be clinically significant even in ESRD patients, whose renal function was highly impaired. The simultaneous use of digoxin and clarithromycin should be avoided even in patients undergoing renal replacement therapy whose renal function is impaired, since digoxin levels may increase unexpectedly.     

Efficacy, safety, and pharmacokinetics of multiple administration of infliximab in Behçet's disease with refractory uveoretinitis

OBJECTIVE: Beh?et's disease (BD) with uveoretinitis is a chronic refractory disease accompanied by ocular attacks. As the decrease in visual acuity due to ocular attack is seriously life-threatening, development of a new drug is anticipated. Since tumor necrosis factor-a (TNF-a) is involved in the symptoms of BD, particularly the activity of ocular symptoms, suppression of TNF-a might be effective in treating BD with uveoretinitis. We conducted a clinical trial of infliximab, an anti-TNF-a chimeric monoclonal antibody, in patients with BD. METHODS: In this open label trial, the efficacy, safety, and pharmacokinetics of repeated administration of infliximab were evaluated in 13 patients with BD accompanied by refractory uveoretinitis. Infliximab was administered 4 times at Weeks 0, 2, 6, and 10 at doses of either 5 or 10 mg/kg by intravenous drip infusion. Frequency of ocular attacks was used as the primary index for evaluation of efficacy, with visual acuity and extraocular symptoms as secondary indices. RESULTS: The mean numbers of ocular attacks, converted to frequency per 14 weeks, were 3.96 times for the 5 mg/kg group and 3.79 times for the 10 mg/kg group during the observation period. Following treatment with infliximab, they decreased to 0.98 times and 0.16 times, respectively. A serious adverse event, tuberculosis, was observed in one case in the 10 mg/kg group. Serum infliximab concentration increased with dosage. CONCLUSION: Administration of infliximab in patients with BD with refractory uveoretinitis suppressed the frequency of ocular attacks, and multiple administration was well tolerated, suggesting that infliximab is effective for this condition.     

Severe persistent bone marrow failure following therapy with 2-chlorodeoxyadenosine for relapsing juvenile xanthogranuloma of the brain

2-Chlorodeoxyadenosine (2-CdA) has been successfully used in children to treat refractory Langerhans cell histiocytosis and juvenile xanthogranuloma (JXG) as salvage therapy. Although 2-CdA is generally well-tolerated, with temporary myelosuppression as the primary dose-limiting toxicity, prolonged myelosuppressive, and immunosuppressive effects have been reported. We describe an adolescent patient with refractory multiple central nervous system JXG, with the lesion size markedly reduced after treatment with 2-CdA. However, severe transfusion-dependent bone marrow failure developed after five courses of 2-CdA. He underwent successful bone marrow transplantation from his HLA compatible sister with reduced intensity conditioning.     

Slam-associated protein plays a key role in development of autoimmunity

In 1995, the SLAM-associated protein (SAP) gene was cloned in our laboratory, and patents were subsequently filed in the USA, EU and Canada. In 1998, the SAP gene was shown to be defective in patients with X-linked lymphoproliferative disease. Since this discovery, the gene has been demonstrated to play a significant role in viral protection, cytokine production and life-long immune memory (vaccination). This article reviews the crucial role of SAP in the development of autoimmunity.     

Giant thrombus in the ascending aorta that caused systemic embolism

Although an ascending aortic thrombus is a rare finding, it may cause major embolic complications. We report a case of a 58-year-old male who suffered from cerebral and left renal infarctions due to emboli from a giant thrombus in the ascending aorta. The thrombus was demonstrated by computed tomography and transesophageal echocardiography. Ten days after the initiation of anticoagulation therapy, surgery was performed. After a median sternotomy was performed and cardiopulmonary bypass was initiated, the ascending aorta was replaced with a synthetic graft under hypothermic circulatory arrest and retrograde cerebral perfusion. The excised specimen revealed a 3.5×3.0×3.0-cm pedunculated thrombus. The patient's postoperative recovery was uneventful, and there was no recurrence of aortic thrombosis during one year of postoperative follow-up. The patient had no coagulation disorders, and the etiology of this giant thrombus remains unclear. We believe that initial treatment for an ascending aortic thrombus should be emergency surgery before it leads to major embolic events. However, the treatment strategy for a thrombus causing cerebral infarction is sometimes difficult to develop.     

Introduction of human β-defensin-3 into cultured human keratinocytes and fibroblasts by infection of a recombinant adenovirus vector

Cultured epidermal autografts and cultured skin substitute are vulnerable to infection. Human beta defensin (HBD)-3 is an antimicrobial peptide that exhibits a wide-spectrum antimicrobial activity against gram-positive/negative bacteria and fungi. This study determined whether normal human keratinocytes (NHKs) and human dermal fibroblasts (HDFs) transfected with the HBD-3 gene secrete HBD-3 peptide with an antimicrobial activity. An adenovirus vector with an HBD-3 cDNA inserted downstream of the CMV promoter (ADhBD3) was created. The HBD-3 gene was introduced into NHKs and HDFs via ADhBD3 infection. HBD-3 gene expression in each type of transfected cells was evaluated by RT-PCR. The presence of HBD-3 peptide in the culture supernatants of each type of transfected cells was evaluated by Western blotting. The antimicrobial activities of the culture supernatants of each type of transfected cells against several bacterial strains were also measured. Both NHKs and HDFs infected with ADhBD3 expressed the HBD-3 gene and secreted HBD-3 peptide into culture supernatants. These supernatants exhibited a strong bacteriocidal activity against a Staphylococcus aureus reference strain and methicillin-resistant S. aureus (MRSA). NHKs and HDFs transfected with the HBD-3 gene secrete HBD-3 peptide with an antimicrobial activity against S. aureus and MRSA.