Virological and histological responses to one year alpha-interferon-2a in hemodialyzed patients with chronic hepatitis C.

BACKGROUND: alpha-Interferon-2a (IFNalpha) alone is a therapy of limited proven benefit for non-uremic patients with chronic hepatitis C virus (HCV) infection. In dialyzed patients, such an effect is suggested on small short-term studies without sufficient clinical and virologic follow-up to document any sustained effect. PROTOCOL: Twelve chronically hemodialyzed patients with chronic hepatitis C and waiting for renal transplantation were included in a prospective open study of treatment with IFNalpha. We used, as did others, doses of 3 million units (MU), three times a week, but for a longer period of treatment of 12 months. Follow-up was continued for 6 months after the end of IFNalpha in order to document any sustained biochemical, virological and histological responses. RESULTS: Aminotransferase levels returned to the normal range within 1-2 months of treatment in all patients in whom they had been elevated at baseline. At 1 month of treatment, serum HCV-RNA was not detected in 5 (41%) patients and in 9 (75%) at 12 months. A sustained virological response was documented in 4 (33%) patients 6 months after the end of treatment. Relapse occurred in 5 patients within 2 months after IFNalpha withdrawal. HCV genotype was not predictive of any sustained response. At inclusion, using the histologic Metavir scoring system, half of the patients had low-grade cytolytic activity and none had cirrhosis. After IFNalpha, liver biopsy specimens were available from 9 patients and showed histologic improvement in 3. IFNalpha tolerance was poor, inducing a 5% mean weight loss and the acute rejection of two nonfunctioning kidney grafts. CONCLUSION: This study documents that administration of IFNalpha at 3 MU three times a week, for 12 months, in hemodialysis patients with chronic hepatitis C was efficient for clearing the serum of HCV-RNA in 75% of the patients. A sustained response was maintained in one third of these patients after cessation of IFNalpha, and was predicted by the early serum clearance of the virus within the first 2 months of treatment. We confirm that a 12-month treatment period carries a higher sustained response rate than shorter treatment periods. These encouraging results call for larger studies in uremic patients, using IFNalpha alone or in association with new antiviral drugs.

Intestinal calcium absorption from mineral water.

Little is known about the bioavailability of calcium in water and various beverages. Some mineral waters contain large amounts of calcium that could compensate for insufficient consumption of dairy products. The fractional intestinal absorption of calcium (FCA) was measured in 12 healthy adult volunteers, using a trace dose of radiocalcium and 200 mg of calcium carrier, part of which was calcium contained in mineral water. Measurements were performed in fasting subjects consuming a standard breakfast. In all the subjects, three mineral waters with a calcium concentration of 10.4, 78, and 467 mg/l, respectively, were tested. Calcium absorption occurred with the same kinetics for each of the mineral waters tested, and within 2 h of the oral dose, equilibrium was reached between absorbed calcium and calcium remaining in the gastrointestinal tract, which resulted in a constant FCA value. This level comprising between 34.1 and 37.0% was independent of the daily calcium consumption and the chemical content of the mineral water. In conclusion, calcium contained in mineral waters in available for intestinal absorption. In a given normal subject, the only rate-limiting factor for FCA is the amount of total calcium given with foods and drinks. Mineral waters containing calcium are recommended as a supplemental source of calcium to achieve optimal calcium requirements, especially in aged people with lactose intolerance.

Duodenal calcium binding protein and active calcium transport in rats: are they functionally related?

The effects of calcitriol and a novel calcitriol analogue, 22-oxacalcitriol (OCT) on duodenal Ca transport, calbindin-D9k mRNA, and calbindin-D9k content were studied in two animal models reflecting common human pathologies, namely arterial hypertension and chronic renal failure, as well as in normal rats. The hormone or its analogue were administered intraperitoneally to vitamin-D-replete rats. Active Ca transport was increased in both spontaneously hypertensive rats (SHR) and in normotensive control WKY rats 5 h after calcitriol dosing of either 60 and 600 ng per rat. In WKY, calbindin-D9k content was slightly increased after the injection of 60 ng calcitriol, but not of 600 ng calcitriol whereas calbindin-D9k mRNA stayed essentially unchanged. In contrast, active Ca transport was significantly stimulated after the higher dose of 600 ng calcitriol. In SHR, while both doses of calcitriol increased active Ca transport, they had no stimulatory effect on calbindin-D9k mRNA or protein. In chronically uraemic rats, active Ca transport, duodenal calbindin-D9k and calbindin-D9k mRNA were stimulated after the injection of two subsequent doses of 300 ng calcitriol per rat. OCT treatment at same dosage led to a similar stimulation of calbindin-D9k and calbindin-D9k mRNA, but failed to induce an increase in active Ca transport. These results show that the stimulation of intestinal active Ca transport and calbindin-D9k can be entirely dissociated at the protein synthesis and the mRNA expression level (1) after calcitriol administration to normal and hypertensive rats, and (2) after OCT administration to uraemic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of 22-oxa-calcitriol on calcium metabolism in rats with severe secondary hyperparathyroidism.

The purpose of the present study was to examine the effect of a two day and a five day administration of 22-oxa-calcitriol (OCT) on calcium metabolism in rats with advanced chronic renal failure and severe secondary hyperparathyroidism. A first series of 27 uremic rats received either placebo, OCT or calcitriol (0.3 microgram i.p./rat) 48 and 24 hours before sacrifice. A second series of 18 uremic rats received either placebo, OCT (0.3 microgram i.p./rat) or calcitriol (0.05 microgram i.p./rat) for five days. We found that after 48 hours (series 1) both calcitriol and OCT increased blood ionized calcium (Ca2+) as compared to vehicle (1.23 +/- 0.04 and 1.10 +/- 0.02 mM, P < 0.01 and P < 0.05, respectively vs. control, 1.02 +/- 0.03 mM). Duodenal Ca transport (S/M) using the everted gut sac technique was not stimulated by OCT, even though it increased from 2.8 +/- 0.4 to 7.0 +/- 0.6 (P < 0.01) with calcitriol. In contrast, duodenal calbindin-D9k mRNA expression and protein content increased to a similar extent with OCT and calcitriol. Calcitriol was more potent in reducing plasma iPTH1-34 levels than OCT: 344 +/- 75 pg/ml (calcitriol) versus 632 +/- 46 pg/ml (OCT) compared with 897 +/- 74 pg/ml (control), P < 0.01. In the second series of rats, the injection of OCT (0.3 microgram i.p./rat) over five days was less effective than the lower dose of calcitriol (0.05 microgram i.p./rat) in reducing circulating iPTH: 110 +/- 26 (calcitriol) and 281 +/- 64 (OCT) versus 624 +/- 135 pg/ml (control), P < 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of acyclovir to prevent cytomegalovirus infection in renal allograft recipients.

Cytomegalovirus (CMV) is the most common opportunistic pathogen following renal transplantation and remains a major concern in transplantation centers owing to its high morbidity and impact on renal allografts. Pending more effective antiviral drugs, efforts have been directed toward prevention strategies. We conducted a retrospective analysis to evaluate the efficacy of various prophylactic options used at our institution during the period April 1986 to August 1990. All CMV-negative patients with CMV-negative kidneys (D-R-) received screened, CMV-negative blood products (n = 19). CMV-specific immunoglobulins (CMV Ig) were used in 6 patients at increased risk for primary CMV infection and acyclovir was administered to 21 patients at an initial intravenous dose of 5 mg/kg body weight; then oral doses of 800-3200 mg per day were given according to the patients' estimated creatinine clearance. Thirty-two patients did not receive any CMV prophylactic treatment and served as controls. CMV monitoring of the patients during the first 6 months after transplantation showed an overall infection and disease rate of 81% and 38.1%, respectively, in the acyclovir-treated group. Compared with controls, the incidences of infection and disease were higher in the acyclovir-treated patients, with a significant difference for CMV infection (P = 0.002, generalized Wilcoxon test). Only 1 of the 19 D-R- patients presented with CMV infection. CMV Ig-treated patients tended to have less severe disease without any apparent reduction in infection incidence. Given the high rate of infection in patients at risk, we infer that high-dose acyclovir does not prevent CMV infection in our setting of renal transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)