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The use of temporary hemodialysis catheters (THC) has facilitated the delivery of hemodialysis to patients lacking functional vascular access. However, the use of these catheters is often associated with infections or mechanical complications.A review of experiences at a tertiary referral center in Iraq with the use of 128 THC catheters in 103 patients was undertaken over one year, to identify indications for use and outcomes and issues limiting survival.The indications for insertion of THC included the following: as acute dialysis access for patients with chronic renal failure (CRF) in 42.1%, failed arteriovenous fistulae in 14%, acute renal failure in 18%, failed prior THC in 18.7%, absent vascular access in patients with transplant rejection in 6.2% and severe anasarca in one patient (0.78%). The site of insertion was the right internal jugular vein in 101 patients, the right subclavian vein in 23 patients, and the left internal jugular vein in four patients. During follow-up, 86 catheters were removed: 62 in patients with end-stage renal disease (ESRD), 23 in patients with acute renal failure and one patient with severe anasarca. The reasons for removal of THC in ESRD patients were elective removal (44%), catheter related sepsis (CRS) in 30%, mechanical complications (19%) and others (7%). The subclavian site was associated with infection in 20% of patients, while the internal jugular site was associated with infection in 22.7% of patients. For patients in whom THC removal was for infection, a post removal culture of the catheter tip showed Staphylococcus aureus in 57.8%, Klebsiella in 15.7%, Pseudomonas in 15.7% and Streptococcus hemolyticus in 10.5% of the cases.THC is advantageous for vascular access in patients with acute renal failure. Infections and blockage significantly reduce the survival of THC in patients with ESRD. Approaches to minimize these complications are likely to lead to improved clinical outcomes with THC use.

Many patients with systemic lupus erythematosus (SLE) and fibromyalgia (FM) may spend less time exposed to the sun than healthy individuals and thus might have low vitamin D levels. It is known that hydroxychloroquine (HCQ) inhibits conversion of 25(OH)- to 1,25(OH)2-vitamin D both in vitro and in patients with sarcoidosis. We assessed winter serum 25(OH)- and 1,25(OH)2-vitamin D levels in patients with SLE and FM. We recruited 25 consecutive female SLE and 25 female FM patients in London, Ontario, between January and March 2000. Subjects completed a brief questionnaire. Serum levels of 25(OH)-, 1,25(OH)2-vitamin D, and parathyroid hormone (PTH) were measured. In SLE patients mean 25(OH)-vitamin D was 46.5 nmol/l and mean 1,25(OH)2-vitamin D was 74.4 pmol/l. In FM patients these means were 51.5 nmol/l and 90.1 pmol/l, respectively. Serum 25(OH)-vitamin D levels did not significantly differ between SLE and FM patients, nor after adjusting for age and vitamin D, milk consumption, and sun block use. In 14 of the SLE patients and 12 of the FM patients 25(OH)-vitamin D levels < 50 nmol/l were found. SLE patients not using vitamin D supplements had lower 25(OH)-vitamin D levels than those who did. 1,25(OH)2-vitamin D tended to be lower in the SLE compared to the FM patients. This difference could be attributed to HCQ use: HCQ users (n = 17) had lower 1,25(OH)2-vitamin D levels than nonusers (n = 33); the mean adjusted difference was 24.4 pmol/l (95% CI 2.8-49.9). Half the SLE and FM patients had 25(OH)-vitamin D levels < 50 nmol/l, a level at which PTH stimulation occurs. Our data suggest that in SLE patients HCQ might inhibit conversion of 25(OH)-vitamin D to 1,25(OH)2-vitamin D

1. Long-term treatment with beta 2-adrenoceptor agonists can lead to a decreased therapeutic efficacy of bronchodilatation in patients with obstructive pulmonary disease. In order to examine whether or not this is due to beta-adrenoceptor desensitization, human bronchial muscle relaxation was studied in isolated bronchial rings after pretreatment with beta 2-adrenoceptor agonists. Additionally, the influence of pretreatment with dexamethasone on desensitization was studied. 2. The effect of beta 2-agonist incubation alone and after coincubation with dexamethasone on density and affinity of beta-adrenoceptors was investigated by radioligand binding experiments. 3. In human isolated bronchi, isoprenaline induces a time- and concentration-dependent beta-adrenoceptor desensitization as judged from maximal reduction in potency by a factor of 7 and reduction of 73 +/- 4% in efficacy of isoprenaline to relax human bronchial smooth muscle. 4. After an incubation period of 60 min with 100 mumol l-1 terbutaline, a significant decline in its relaxing efficacy (81 +/- 8%) and potency (by a factor 5.5) occurred. 5. Incubation with 30 mumol l-1 isoprenaline for 60 min did not impair the maximal effect of a subsequent aminophylline response but led to an increase in potency (factor 4.4). 6. Coincubation of dexamethasone with isoprenaline (120 min; 30 mumol l-1) preserved the effect of isoprenaline on relaxation (129 +/- 15%). 7. In radioligand binding experiments, pretreatment of lung tissue for 60 min with isoprenaline (30 mumol l-1) resulted in a decrease in beta-adrenoceptor binding sites (Bmax) to 64 +/- 1.6% (P0.05), while the antagonist affinity (KD) for [3H]-CGP-12177 remained unchanged. 8. In contrast, radioligand binding studies on lung tissue pretreated with either dexamethasone (30 mumol l-1) or isoprenaline (30 mumol l-1) plus dexamethasone (30 mumol l-1) for 120 min did not lead to a significant change of Bmax (160 +/- 22.1% vs 142.3 +/- 28.7%) or KD (5.0 nmol l-1 vs 3.5 nmol l-1) compared to the controls. 9. In conclusion, pretreatment of human bronchi with beta-adrenoceptor agonists leads to functional desensitization and, in lung tissue, to down-regulation of beta-adrenoceptors. This effect can be counteracted by additional administration of dexamethasone. Our model of desensitization has proved useful for the identification of mechanisms of beta-adrenoceptor desensitization and could be relevant for the evaluation of therapeutic strategies to counteract undesirable effects of long-term beta-adrenoceptor stimulation.