Pegylated asparaginase in combination with high-dose methotrexate for consolidation in adult acute lymphoblastic leukaemia in first remission: a pilot study

The German Multicentre acute lymphoblastic leukaemia (ALL) study group (GMALL) performed a pilot study using pegylated asparaginase (PEG-ASP) in combination with high-dose methotrexate as consolidation therapy in the 05/93 protocol. The aim of the study was an intra-individual comparison of two different doses of PEG-ASP in 26 patients, with regard to the depletion of asparagine in serum and toxicity. 'Pharmacokinetic' monitoring was performed to evaluate the effect of an intra-individual dose escalation of PEG-ASP from 500 to 1000 U/m2 intravenously in successive doses. Serum asparaginase activity was targeted at > or =100 U/l for 1 week and > or =50 U/l for 10 d. The second course of PEG-ASP was administered to 23 patients. Due to hypersensitivity reactions in five patients, only 18 patients were evaluable for pharmacokinetic monitoring. With respect to the PEG-ASP activity, an effective depletion of asparagine could be postulated in the majority of patients during 10 d after the first administration. The effect of an intraindividual dose escalation form 500 to 1000 U/m2 was evaluable in 17 of 22 patients. An increment in peak PEG-ASP activity >70% was observed in 65% of the patients. PEG-ASP was well tolerated. Despite the long half-life of PEG-ASP, neither pancreatic nor central nervous toxicities occurred among the 26 adult patients treated in this pilot study.

[Secondary and primary prophylaxis of gastropathy associated with nonsteroidal antiinflammatory drugs or low-dose-aspirin: a review based on four clinical scenarios]

Based on current references four clinical scenarios were discussed and different management strategies were compared for secondary and primary prophylaxis of ulcer or peptic ulcer bleeding under continuous therapy with non-steroidal antiinflammatory drugs (NSAID) or low-dose-aspirin, for H.pylori-positive and H.pylori-negative patients. Used as secondary prophylaxis eradication alone is insufficient in preventing recurrent peptic ulcer or recurrent ulcer bleeding for H.pylori-positive patients who continue to take unselective NSAIDs. Maintenance therapy with PPIs or switching from nonselective NSAID to COX-2-inhibitors is required after eradication of H.pylori or primary H.pylori-negative patients. Further evaluation is needed of what kind of secondary prophylaxis - maintenance therapy with PPI or switching to COX-2-inhibitor - is more (cost-)effective. It is sufficient to use eradication of H.pylori alone as secondary prophylaxis in preventing recurrent peptic ulcer or recurrent ulcer bleeding for H.pylori-positive patients, who continue to take low-dose-aspirin. Maintenance therapy with PPI is not generally required. However it can be considered for patients with increased risk for gastrointestinal complications (previous history of peptic ulcer, age over 65 years, concomitant use of corticosteroids, anticoagulants or individual NSAID with higher risk for gastrointestinal complications, serious cardiovascular disease). Switching from low-dose-aspirin to clopidogrel is not required. Used as primary prophylaxis in preventing peptic ulcer or ulcer bleeding before starting long-term therapy with NSAIDs, COX-2-inhibitors or unselective NSAIDs concomitant with PPIs are recommended for patients with increased risk for gastrointestinal complications. Patients starting long-term therapy with unselective NSAIDs should be screened for H.pylori and eradicated. There are no valid data supporting screening for H.pylori and eradication for patients starting long-term therapy with low-dose-aspirin. Further studies are needed to evaluate a possible benefit for patients with increased risk for gastrointestinal complications.

[Day-night variability of the prehospital phase of acute myocardial infarct]

While a circadian rhythm in the onset of acute myocardial infarction (AMI) is well established, little is known about the variability of prehospital delay and decision processes. Seven hundred and thirty-nine consecutive AMI patients (median age 65.3 years; 30.2% women) with a median decision time of 60 min and a total prehospital delay of 180 min were studied. In 30.9% of patients onset of AMI symptoms was at night (10.00 p.m.-06.00 a.m.). At night patient decision time was significantly longer than during daytime (120 vs 45 min, difference 75 min; p < 0.001), total prehospital delay was prolonged accordingly (240 vs 170 min, difference 70 min; p < 0.001). The relative risk (RR; 95% confidence interval, CI) for a late decision (> 1 h) to seek medical care at night was significantly increased in females (RR 1.96; CI 1.07-3.61, p = 0.028), non-smokers (RR 2.49; CI 1.42-4.39, p = 0.001) and patients with radiation of anginal pain (RR 2.34; CI 1.32-4.15; p = 0.003). Of all patients with a late decision to seek medical care at night, 95.6% belonged to one of these groups. These variables were not significant for early or late decisions during daytime. Decision processes of AMI patients may be different during daytime and at night. In conclusion, in AMI patients, decision time to seek medical help is prolonged at night. Simple clinical variables (female sex, non-smokers, radiation of anginal pain) identify patients at high risk for a late decision at night. This information should be included into public and individualized education campaigns.

Emotional attitudes toward symptoms and inadequate coping strategies are major determinants of patient delay in acute myocardial infarction

BACKGROUND

Early reperfusion treatment in acute myocardial infarction (AMI) preserves ventricular function and saves lives. After onset of AMI symptoms, patients often delay for hours until the decision to seek medical help.

AIM

Of the MI-heart (Myocardial Infarction--HElp seeking And ReacTions) study was to identify factors determining patient decision delay.

METHODS

739 consecutive patients with confirmed AMI (median age 65.3 years, 30.2% females) were studied after transfer from the intensive care unit. A standardized interview covered AMI symptoms, attitudes toward symptoms, coping strategies, and clinical and sociodemographic variables.

RESULTS

Of patients, 93.3% knew an AMI could be deadly. 43.9% of the patients who suspected an AMI, and knew it could be deadly, decided late (> 1 hour) to seek medical help. In univariate analyses, attitudes toward symptoms and coping strategies had the highest impact on a late decision. Stepwise logistic regression identified the following independent contributors to a late decision to seek medical help (relative risk, 95% confidence interval): wanting to wait and see (3.53; 2.32-5.39), not taking symptoms seriously (2.47; 1.64-3.72), not wanting to bother anybody (2.14; 1.29-3.57), symptoms improving at first (2.33; 1.52-3.56), asking others for advice (0.46; 0.30-0.71), taking pain medication (2.01; 1.01-4.03), age > 65 years (1.69; 1.17-2.44), very strong intensity of angina (0.60; 0.42-0.87).

CONCLUSIONS

Emotional attitudes to AMI symptoms and inadequate coping strategies are the major determinants of patient decision delay. They should be considered as a key factor in patient and public education. Modification of these emotional factors might best be achieved by an individualized approach.

[Bradycardia despite hyperthyroidism]

Hyperthyroidism is usually associated with tachycardia, hypothyroidism with bradycardia. After observing clinically inapparent hyperthyroidism in patients requiring pacemaker implantation, we studied the occurrence of hyperthyroidism in patients receiving a first permanent pacemaker. Of 237 patients (age 71.4 +/- 8.9 years; 54.9% females), 16 (6.75%) had subclinical (TSH < 0.1 mE/l and fT3 < or = 9.0 pmol/l) and 4 (1.69%) overt hyperthyroidism (TSH < 0.1 mE/l and fT3 > 9.0 pmol/l). Prevalence of hyperthyroidism was similar to that in the general population. Compared to euthyroid patients, in the patients with subclinical or overt hyperthyroidism there were significantly more females (n = 16) than males (n = 4; p = 0.018). Hyperthyroid patients were older (75.0 +/- 9.6 vs. 70.7 +/- 8.9 years; p = 0.015). At follow-up, all patients had a relevant proportion of pacemacer-induced beats. Clinical signs of hyperthyroidism or cardiac symptoms were not different between groups. In conclusion, bradycardia does not exclude the presence of hyperthyroidism. Temporary pacing is recommended in thyreotoxicosis with bradycardia. In contrast, primary implantation of a permanent pacemaker appears to be adequate in patients with bradycardia, cardiovascular disease and an additional diagnosis of hyperthyroidism.

Out-of-hospital cardiac arrest in north-east Germany: increased resuscitation efforts and improved survival

In the years after 1989 major political and socioeconomic changes have taken place in East Germany. In parallel, emergency medical services (EMS) were restructured according to western standards. In Stralsund the EMS was restructured from a single to a two tier system with implementation of a second ambulance base in 1990. The number of household telephone extensions more than doubled. To analyze the effects of these changes, patients receiving advanced life support (ALS) for out-of-hospital cardiac arrest of cardiac origin (OHCA) between 1984 and 1988, and from 1991 to 1997 were studied. Adjusted per 100,000 inhabitants, the number of OHCA patients receiving ALS increased from 11 per year before 1989 to 52 per year after 1990 (P < 0.01). Survival without relevant neurologic defects was achieved in 3.7% (2/53) of patients before 1989 and in 8.1% (22/273) after 1990. Response time of the ALS unit shortened from 11.0 +/- 1.4 to 9.0 +/- 0.4 min (n.s.), while response time of any EMS shortened from 11.0 +/- 1.4 to 6.1 +/- 0.3 min (P < 0.005). Adjusted for observation period and population served, there was a 10-fold increase in the number of resuscitations attempted at home and an 8-fold increase in the absolute number of OHCA survivors without relevant neurological defects. In parallel to socioeconomic changes, the restructuring of the EMS in Stralsund and the rapid expansion of the telephone network led to a significant increase in the number of patients successfully resuscitated from OHCA. If the present results can be transferred to other former socialist countries of East and Middle Europe, they may have important implications for the EMS in these regions.

Intensive chemotherapy with idarubicin, ara-C, etoposide, and m-AMSA followed by immunotherapy with interleukin-2 for myelodysplastic syndromes and high-risk Acute Myeloid Leukemia (AML)

Intensive chemotherapy followed by treatment with interleukin-2 (IL-2) was evaluated in a prospective, randomized, multicenter trial including 18 patients with refractory anemia with excess of blasts in transformation (RAEB-T), 86 patients with acute myeloid leukemia (AML) evolving from myelodysplastic syndromes, and six patients with secondary AML after previous chemotherapy. Median age was 58 years (range: 18-76 years). Forty-nine patients (45%) achieved a complete remission (CR) after two induction cycles with idarubicin, ara-C, and etoposide, 52% of them aged </=60 years and 35% aged >60 years (p=0.06). After two consolidation courses, patients were randomized to four cycles of either high- or low-dose IL-2. Patients aged up to 55 years with an HLA-identical sibling donor were eligible for allogeneic bone marrow transplantation. The median relapse-free survival was 12.5 months, with a probability of ongoing CR at 6.5 years of 19%. Overall survival of all patients was 8 months, and 21 months for the CR patients. Median survival was significantly longer among patients aged </=60 years than among the older patients (16 vs 6 months, p<0.001). Median duration of survival and relapse-free survival were not statistically different in the two IL-2 treatment arms.

Regulation of beta2-microglobulin expression in different human cell lines by proinflammatory cytokines

BACKGROUND

Proinflammatory monocytic cytokines such as interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF-alpha) and IL-6 have been incriminated in the pathogenesis of elevated beta2-microglobulin (beta2M) serum concentrations in patients undergoing haemodialysis with so-called bioincompatible dialyser membranes. However, neither the source of the elevated serum beta2M nor the precise role of monocytic cytokines in the expression of the beta2M gene have been elucidated conclusively. The aim of the current study was to evaluate whether monocytic cytokines, and in particular IL-6, are regulators of beta2M gene expression in human hepatoma cells, T-lymphocytes and monocytes.

METHODS

HepG2 and HuH7 human hepatoma cells, Jurkat T-cells, monocytic MonoMac6 cells, primary human monocytes and synoviocytes were stimulated with IL-1beta, IL-6, interferon-alpha (IFN-alpha), IFN-gamma or conditioned media from lipopolysaccharide (LPS)-treated monocytes. Expression of beta2M mRNA was analysed by Northern blotting, beta2M protein synthesis was determined by metabolic labelling and immunoprecipitation, and beta2M secretion was measured by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

In all cell types tested, IFN-gamma and, to a lesser extent, IFN-alpha stimulated gene expression of beta2M resulting in an increased synthesis and secretion of beta2M protein. Neither IL-1beta and IL-6 nor supernatants from LPS-treated monocytes were capable of inducing beta2M gene expression, with the exception of a small increase in HuH7 hepatoma cells upon IL-1beta treatment.

CONCLUSIONS

The present study provides evidence that interferons are important regulators of beta2M expression. It also shows that proinflammatory monocytic cytokines do not modulate directly the expression of beta2M in cells of hepatic, monocytic and T-lymphocytic origin. Whether they influence beta2M synthesis and secretion indirectly by modulating interferon synthesis needs to be elucidated.

Metastatic workup of patients with prostate cancer employing alkaline phosphatase and skeletal alkaline phosphatase

PURPOSE

To compare the efficacy of two tests, alkaline phosphatase (AP) and skeletal alkaline phosphatase (SAP) as staging markers to discriminate patients with cancer of the prostate (CaP) with bone metastases (M+) from those without bone metastases (Mo).

MATERIALS AND METHODS

Patients with previously untreated CaP were entered in the retrospective analysis. Serum concentrations of AP (n = 215) and SAP (n = 73) were available. After staging the patients could be divided into 2 groups: Group I: patients with CaP and bone metastases (cT2-4 NxMoss AP: n = 40; SAP: n = 21) Group II: patients with CaP without bone metastases (cT3-4 Nx Mo; pT1-3 No Mo; AP: n = 175; SAP: n = 52).

RESULTS

None of the Mo patients but 71% of the M+ patients exhibited a SAP value above the reference range (< 19 ng/ml). This difference is statistically significant (p < 0.001) and resulted in a sensitivity and specificity of 71% and 100%, respectively. The Youden-index is 0.7. In contrast 7% of the Mo patients and only 13% of the M+ patients exhibited a AP value above the reference range (< 170 U/l). This difference is statistically not significant (p = 0.71) and resulted in a sensitivity and specificity of 13% and 93%, respectively. The Youden-index is 0.06.

CONCLUSION

SAP could become a useful marker in the evaluation of patients with newly diagnosed CaP as it provides more information than AP concerning the skeletal status of these patients.

Simulation of a pheochromocytoma--Munchausen syndrome

A 46-year old female nursing sister was admitted to three different hospitals because of blood pressure crises of 300/150 mmHg which occurred up to six times a day. The rises in blood pressure were accompanied by headache, tachycardia and outbreaks of sweating. Raised catecholamine concentrations were repeatedly measured in the 24-hour urine and in the blood. The diagnosis of pheochromocytoma could therefore be regarded as confirmed. The investigations to establish the localization (including MIBG scintigrams carried out several times) showed negative results. Octreotide scintigraphy finally revealed a raised concentration of nuclides in the right adrenals. Selective venous blood samples showed markedly raised concentrations of adrenaline and noradrenaline in all regions investigated. After removing the right adrenal, which was of normal histological appearance, there was an improvement for six months. Afterwards, up to six blood pressure crises per day were observed once more. Fresh determination of catecholamines at various levels demonstrated the highest concentrations in the left iliac vein. It was then shown that the patient injected catecholamines intravaginally even during the angiographic investigation. A search of the patient s room revealed several ampoules containing noradrenaline and adrenaline as well as syringes and needles. - This case shows that in clinical pictures with typical clinical symptoms and negative results of repeated investigations a factitious disorder must be considered in terms of differential diagnosis especially when female patients with medical knowledge who have ready access to drugs are involved with a history comprising several stays in hospital which have not produced any clarification of their condition.

Remission of IgA nephropathy following treatment of cytomegalovirus infection with ganciclovir

Following the detection of cytomegalovirus antigen in mesangial cells of some patients with IgA nephropathy, an important role of human cytomegalovirus in the pathogenesis of IgA nephropathy has been discussed. We studied a case of IgA nephropathy with rapid deterioration of renal function associated with cytomegalovirus infection. Following an infection of the upper respiratory tract, a 57-year-old woman developed with hematuria and acute renal failure. The histological diagnosis of IgA nephropathy was established and renal function transiently improved during immunosuppressive therapy. However, the ensuing clinical course was complicated by severe bleeding from intestinal ulcera, thrombocytopenia, pneumonia and relapse of renal failure. The histological investigation of colonic mucosa showed characteristic "owl's eye" cells leading to the diagnosis of cytomegalovirus disease as the cause of intestinal bleeding. Immunosuppression was stopped and treatment with ganciclovir started. Pneumonia as well as intestinal bleeding disappeared and, of particular note, renal function improved considerably. Following discontinuation of antiviral therapy CMV-disease reoccurred and renal function deteriorated again. The patient was restarted on ganciclovir therapy and, again, serum creatinine fell quickly. This impressive and reproducible clinical improvement of renal insufficiency under antiviral therapy with ganciclovir provides some evidence for an important role of cytomegalovirus in the pathogenesis of this case of IgA nephropathy.

Retinal capillary density in patients with arterial hypertension: 2-year follow-up

BACKGROUND

Arterial hypertension is known to be an important risk factor for cerebral and cardiovascular disease. Previous studies have demonstrated a decrease of capillary density in the perifoveal network in tandem with decreased capillary flow velocity in patients with essential hypertension. In a prospective study we quantified the retinal microcirculation in order to evaluate the time course of changes in the perifoveal network.

METHODS

Thirty-three patients with essential hypertension (mean age 45 +/- 14 years) underwent video-fluorescein angiographic studies at baseline and at 2 years 28 +/- 6 months) thereafter. The angiograms were obtained with a scanning laser ophthalmoscope and were digitally recorded. By means of digital image analysis we quantified off-line the mean area of perifoveal intercapillary areas (PIA) and the mean capillary flow velocity.

RESULTS

At baseline, the patients with hypertension showed significantly increased PIA and a significantly decreased capillary flow velocity compared with reference values. During the follow-up period the capillary flow velocity decreased further significantly, whereas the PIA showed no significant change.

CONCLUSIONS

The continuous decrease of capillary flow velocity demonstrates a progression of altered microcirculation in patients with essential hypertension whose blood pressure was believed to be well controlled. Further studies with this technique may be useful to determine the influence of antihypertensive therapy and may help to identify patients at risk for cerebrovascular events.

[Is skeletal alkaline phosphatase a valid staging marker in detection of osteoblastic skeletal metastases of prostate carcinoma?]

PURPOSE

For patients with prostate cancer (CaP) the proof of osteoblastic bone metastases is decisive regarding the prognosis as well as the therapeutical concept. To evaluate the efficiency of skeletal alkaline phosphatase (SAP) as staging marker for bone metastases in prostate cancer, SAP was measured in CaP-patients with and without bone metastases compared with prostate-specific antigen (PSA) as the marker of choice till now.

METHOD

73 patients with histological proven, but still untreated CaP were entered into the study. After staging the patients were divided into 3 groups: group I: patients with CaP and bone metastases (n = 21), group II: patients with locally advanced CaP without bone metastases (n = 26), group III: patients with clinically localized CaP without bone metastases (n = 26). Serum concentration for SAP and PSA were determined using radioimmunassay. As reference range we defined serum concentrations for SAP < 19 ng/ml and for PSA < 100 ng/ml.

RESULTS

71% of the patients with bone metastases (group I) showed elevated SAP and PSA serum concentrations. In contrast, patients without bone metastases (group II + III) have normal SAP-values (<19 ng/) and in 19% of the cases elevated PSA-values (>100 ng/ml). This resulted in a sensitivity and specificity of 71% and 100% for SAP and 71% and 81% for PSA. The positive predictive value for osteoblastic bone metastases was 100% for SAP and 60% for PSA.

CONCLUSION

SAP is a useful staging marker in prostate cancer and can contribute for an early detection of osteoblastic bone metastases.

Ultrasensitive analysis of the intestinal absorption and compartmentalization of aluminium in uraemic rats: a 26Al tracer study employing accelerator mass spectrometry

BACKGROUND

Developments in accelerator mass spectrometry (AMS) now permit the determination of femtogram amounts of 26Al in blood and in various tissues with good precision and free of external contamination.

METHODS

In the present study we used trace quantities of 26Al to investigate the intestinal absorption and compartmentalization of aluminium in rats with renal failure (Nx, 5/6 nephrectomy) and in pair-fed controls (C). Single oral doses of 20 ng 26Al were administered to six animals in each group and, subsequently, 24-h post-load 26Al was analysed in serum, urine, bone, liver, and spleen by means of AMS.

RESULTS

Serum concentrations of 26Al were significantly lower in uraemic rats compared to controls, whereas urinary excretion was comparable (Nx, 7.11 +/- 5.78 pg/day vs C, 9.46 +/- 6.10 pg/day), suggesting a higher fraction of ultrafiltrable serum 26Al in uraemia. The target tissues of cellular transferrin-mediated 26Al uptake, liver and spleen, tended to show a larger degree of aluminium accumulation in controls (0.26 +/- 0.31 pg/g vs Nx, 0.14 +/- 0.10 pg/g and 0.37 +/- 0.27 pg/g vs Nx, 0.25 +/- 0.27 pg/g respectively). In contrast, in bone, a site of extracellular aluminium deposition, 26Al concentrations were more elevated in uraemia (1.22 +/- 0.59 pg/g vs C: 0.68 +/- 0.30 pg/g). Estimated total 26Al accumulation in all measured target tissues was significantly higher in uraemic rats (28.15 +/- 9.90 pg vs C: 17.03 +/- 7.03 pg) and total recovery of 26Al from tissue and urine was 26.58 +/- 6.74 pg in controls and 35.75 +/- 7.03 pg in uraemic animals, suggesting a fractional absorption of 0.133% and 0.175% respectively.

CONCLUSIONS

Our data suggest that fractional absorption from a dietary level dose of 26Al is about 0.13%. Compartmentalization occurs in transferrin-dependent target tissues such as liver and spleen; however, in quantitative terms extracellular deposition in bone is more important. Uraemia has a significant effect on the intestinal absorption and compartmentalization of aluminium. It enhances fractional absorption and increases subsequent extracellular deposition of aluminium in bone. However, at the same time uraemia does not increase transferrin-dependent cellular accumulation of aluminium in liver and spleen.

Metastatic workup of patients with prostate cancer employing skeletal alkaline phosphatase

PURPOSE

To compare the efficacy of two tests, prostate-specific antigen (PSA) and skeletal alkaline phosphatase (SAP) as staging markers to discriminate patients with cancer of the prostate (CaP) with bony metastases (M1) from those without bony metastases (Mo).

MATERIAL AND METHODS

Forty-seven untreated patients with Mo (n = 26) and M1 (n = 21) CaP were entered in this study. Serum concentrations for SAP and PSA were determined using two immunoassays.

RESULTS

None of the Mo patients but 65% of the M1 patients exhibited a SAP value above the reference range (< 19 ng/ml). A corresponding cut-offpoint of 100 ng/ml for PSA showed that 27% of Mo patients and only 65% of the M1 patients exhibited a value > 100 ng/ml. This resulted in a sensitivity and specificity of 65% and 100% for SAP and 65% and 73% for PSA.

CONCLUSION

Our findings suggest that SAP could become a useful marker in the evaluation of patients with newly diagnosed CaP as it seems to provide additional information concerning the skeletal status of these patients.

Effect of iron status on the intestinal absorption of aluminum: a reappraisal

Clinical and experimental studies have shown that serum aluminum (Al) is bound to transferrin and that cellular uptake of Al appears to be mediated by transferrin receptors. Based on these findings it is widely believed that intestinal Al absorption occurs via iron-specific, transferrin-dependent pathways and that iron (Fe) deficiency increases the intestinal absorption of Al. However, since no transferrin receptors are expressed on the absorptive surface of small intestinal epithelial cells this notion is doubtful. To further clarify the issue the present study investigated the effect of marked alterations of body Fe stores on the intestinal absorption of Al using three different rat models. (I) Serum Al concentrations and urinary excretion rates of Al were measured in iron-overloaded (Fe+) or iron-deficient (Fe-) rats with either normal (C) or impaired (5/6 nephrectomy) renal function (Nx) employing oral A1 loads in single dose studies. (II) Tissue A1 accumulation as well as serum and urine A1 were determined in respective experimental groups exposed to a prolonged (41 days) dietary Al load. (III) To assess the effect of Fe status on the intestinal absorption of Al directly at the organ level perfusions of in situ rat gut preparations were performed. In the single dose studies administration of Al resulted in similar urinary excretion rates of Al in intact kidney groups (C+Fe-, 229 +/- 85 nmol/5 days; C+Fe+, 240 +/- 59 nmol/5 days) despite marked differences in liver Fe (C+Fe-, 1.34 +/- 0.16 vs. C+Fe+, 55.69 +/- 13.20 mumol/g) and duodenal mucosal Fe (C+Fe-, 0.68 +/- 0.11 vs. C+Fe+, 3.17 +/- 0.82 mumol/g). In addition, mucosal Al concentration 24 hours after the load was not affected by the Fe status (C+Fe-, 37 +/- 16 nmol/g, C+Fe+, 56 +/- 19 nmol/g). Regardless of the Fe status post-load Al excretion was enhanced in Nx rats (Nx+Fe-, 533 +/- 234 nmol/five days, Nx+Fe+, 536 +/- 201 nmol/five days). Irrespective of Fe status a prolonged dietary Al load resulted in a similar increase in tissue Al concentration (nmol/g) in liver (baseline, 159 +/- 22; C+Fe-, 276 +/- 125; C+Fe+, 251 +/- 71; Nx+Fe-, 330 +/- 119; Nx+Fe+, 437 +/- 67) and in bone (baseline, 219 +/- 119; C+Fe-, 433 +/- 174, C+Fe+, 485 +/- 141; Nx+Fe-, 504 +/- 185; Nx+Fe+, 548 +/- 215). The increase in spleen Al was significantly larger in Fe-overloaded rats (baseline, 194 +/- 20; C+Fe+, 511 +/- 129 vs. C+Fe-, 308 +/- 62, P < 0.05; Nx+Fe+, 514 +/- 67 vs. Nx+Fe-, 389 +/- 119, P < 0.05). Brain Al tended to rise in Nx rats only (baseline, 96 +/- 33; Nx+Fe+, 174 +/- 100, Nx+Fe-, 156 +/- 78, P = NS). Analogous results were obtained in in situ intestinal perfusion studies: Fe deficiency and Fe overload both did not affect the time-dependent increase in serum Al in either systemic or portal vein blood. When paracellular intestinal permeability was assessed mannitol absorption was significantly higher in uremic animals as compared to controls. Pharmacological blockade (2 mM kinetin) of the paracellular permeability substantially reduced the time-dependent increase in serum Al in uremic rats but had little effect in control animals, suggesting that even the excess absorption of Al observed in uremia occurs via a paracellular rather than an iron-specific pathway. In conclusion, the findings of the present study provide several lines of evidence against the commonly accepted view that the intestinal absorption of Al occurs via iron-specific pathways. Most likely, this is related to the fact, that neither the absorption of Fe nor the absorption of Al are mediated via transferrin receptors. In addition, the enhanced intestinal absorption of Al observed in uremic rats does also not occur via iron-specific pathways, but seems to due to increased paracellular permeability of the intestine.

Improved outcome in adult B-cell acute lymphoblastic leukemia

A total of 68 adult patients with B-cell acute lymphoblastic leukemia (B-ALL) were treated in three consecutive adult multicenter ALL studies. The diagnosis of B-ALL was confirmed by L3 morphology and/or by surface immunoglobulin (Slg) expression with > 25% blast cell infiltration in the bone marrow (BM). They were characterized by male predominance (78%) and a median age of 34 years (15 to 65 y) with only 9% adolescents (15 to 20 y), but 28% elderly patients (50 to 65 y). The patients received either a conventional (N = 9) ALL treatment regimen (ALL study 01/81) or protocols adapted from childhood B-ALL with six short, intensive 5-day cycles, alternately A and B. In study B-NHL83 (N = 24) cycle A consisted of fractionated doses of cyclophosphamide 200 mg/m2 for 5 days, intermediate-dose methotrexate (IdM) 500 mg/m2 (24 hours), in addition to cytarabine (AraC), teniposide (VM26) and prednisone. Cycle B was similar except that AraC and VM26 were replaced by doxorubicin. Major changes in study B-NHL86 (N = 35) were replacement of cyclophosphamide by ifosphamide 800 mg/m2 for 5 days, an increase of IdM to high-dose, 1,500 mg/m2 (HdM) and the addition of vincristine. A cytoreductive pretreatment with cyclophosphamide 200 mg/m2, and prednisone 60 mg/m2, each for 5 days was recommended in study B-NHL83 for patients with high white blood cell (WBC) count (> 2,500/m2) or large tumor burden and was obligatory for all patients in study B-NHL86. Central nervous system (CNS) prophylaxis/treatment consisted of intrathecal methotrexate (MTX) therapy, later extended to the triple combination of MTX, AraC, and dexamethasone, and a CNS irradiation (24 Gy) after the second cycle. Compared with the ALL 01/81 study where all the patients died, results obtained with the pediatric protocols B-NHL83 and B-NHL86 were greatly improved. The complete remission (CR) rates increased from 44% to 63% and 74%, the probability of leukemia free survival (LFS) from 0% to 50% and 71% (P = .04), and the overall survival rates from 0% to 49% and 51% (P = .001). Toxicity, mostly hematotoxicity and mucositis, was severe but manageable. In both studies B-NHL83 and B-NHL86, almost all relapses occurred within 1 year. The time to relapse was different for BM, 92 days, and for isolated CNS and combined BM and CNS relapses, 190 days (P = .08). The overall CNS relapses changed from 50% to 57% and 17%, most probably attributable to the high-dose MTX and the triple intrathecal therapy. LFS in studies B-NHL83 and B-NHL86 was significantly influenced by the initial WBC count < or > 50,000/microL, LFS 71% versus 29% (P = .003) and hemoglobin value > or < 8 g/dL, LFS 67% versus 27% (P = .02). Initial CNS involvement had no adverse impact on the outcome. Elderly B-ALL patients (> 50 years) also benefited from this treatment with a CR rate of 56% and a LFS of 56%. It is concluded that this short intensive therapy with six cycles is effective in adult B-ALL. HdM and fractionated higher doses of cyclophosphamide or ifosphamide seem the two major components of treatment.

Long-term ciclosporine A treatment in adults with minimal change nephrotic syndrome or focal segmental glomerulosclerosis

To evaluate the efficacy and safety of long-term ciclosporine A (CSA) treatment in idiopathic nephrotic syndrome, we prospectively followed immunosuppressive therapy in 22 nephrotic adults for a median of 32 months (range 7-91 months) and obtained repeat renal biopsies. CSA induced complete remission in 60.0% and 14.3% of patients with minimal change nephrotic syndrome (MCNS) (n = 7), respectively. In addition, partial remissions were achieved in 20.0% of patients with MCNS and in 42.9% of patients with FSGS. Resolution of proteinuria was strictly CSA-dependent and no sustained remission occurred following withdrawal, thereby requiring long-term treatment in 18 patients. In 10 patients CSA was administered for more than 43 months. During maintenance therapy the antiproteinuric effect of CSA was preserved and renal function as well as blood pressure remained stable in patients with MCNS, whereas renal function deteriorated in two patients with FSGS due to progression of the underlying renal disease. Renal biopsies revealed slight signs of CSA toxicity in four patients. However, in no case loss of renal function was attributable to these lesions. In conclusion, the present data suggest that long-term maintenance treatment of MCNS with CSA is efficacious and safe at least for a period of up to 43 months. In contrast, CSA has some effect on proteinuria in FSGS, but the results are less favorable.

Osteocalcin in patients with rheumatoid arthritis. A one-year followup study

OBJECTIVE

To analyze clinical, radiological, and drug (disease modifying antirheumatic drug, DMARD) dependent factors influencing bone turnover in patients with rheumatoid arthritis (RA).

METHODS

We investigated in a one-year double blind randomized study comparing intramuscular (im) gold with im methotrexate (MTX), whether the variation of inflammatory activity or functional capacity, the ascending anatomic stage, or DMARD treatments have an influence on bone formation (osteocalcin) in patients with RA.

RESULTS

Patients (n = 48) enrolled at the beginning of our study had significantly increased osteocalcin levels (3.45 +/- 0.93-->4.42 +/- 1.39 ng/ml p < 0.02) after one year if inflammatory activity decreased (> or = 1 SD: erythrocyte sedimentation rate (ESR) 26.4 mm/h, C-reactive protein (CRP) 3.8 mg/dl). We found a significant negative correlation of the one-year CRP- (r = -0.44, p < 0.001) or ESR differences (r = -0.45, p < 0.001) with the corresponding osteocalcin differences. This was also evident if these patients were pooled with 15 patients excluded from the double blind study as already receiving DMARD treatment (n = 63; p < 0.01). Patients with impaired functional capacity also had significantly reduced osteocalcin levels (p < 0.01). In both cases, alkaline phosphatase showed no significant differences.

CONCLUSIONS

Our data suggest that osteocalcin, a useful followup variable of bone turnover, is changed significantly (p < 0.02) in patients with RA regarding inflammatory activity and functional capacity. In contrast to alkaline phosphatase, a fall in inflammatory activity stimulated and impairment of functional capacity significantly decreased osteocalcin levels in patients with RA.

Contrast-enhanced computed tomography for demonstration of bilateral renal cortical necrosis

Bilateral renal cortical necrosis as a rare form of acute renal failure was encountered in two patients with sepsis and acute renal failure. In both cases contrast-enhanced computed tomography showed characteristic findings: absent specification of the renal cortex and enhancement of subcapsular and juxtamedullary areas and of the medulla without excretion of contrast medium. Establishing an early diagnosis and visualizing the extent of renal cortical necrosis by means of contrast-enhanced computed tomography allow a prognostic evaluation of renal function and further planning of therapy.

Quantification of retinal capillary density and flow velocity in patients with essential hypertension

Arterial hypertension is known to be an important risk factor for cerebral and cardiovascular disease. Previous studies in rats have demonstrated that changes in both capillary density and vessel diameter may contribute to increased vascular resistance in hypertension. In vivo studies of human subjects with essential hypertension revealed a reduction in the number of arterioles in the skin and conjunctiva; no other in vivo data are available from other tissues. By means of a new imaging technique, capillary density and capillary blood flow velocity can now be assessed in the human retina. We undertook the present investigation to determine whether patients with essential hypertension and only minor clinical retinal vascular alterations have decreased retinal capillary density and altered capillary flow velocity. Seventeen hypertensive patients with only minor retinal vascular alterations and 17 healthy volunteers matched for age were selected. All study participants underwent ophthalmologic examination and fluorescein angiographic studies by means of scanning laser ophthalmoscopy. Capillary density and capillary blood flow velocity in the perifoveal network were evaluated from the angiograms. The retinal microcirculation in the perifoveal capillary network of hypertensive patients showed significant alterations. Both the capillary density and capillary flow velocities were significantly reduced compared with the control group. For the first time alterations of capillary blood flow and capillary density in a vascular network very similar to that of the brain have been demonstrated in hypertensive patients in vivo. Further studies with this technique may help identify patients at high risk for cerebrovascular diseases.

[Retinal hemodynamics in patients with arterial hypertension]

Arterial hypertension is a risk factor for the development of retinal, cerebral and renal microangiopathy. Therefore, a prospective study was started to investigate the progression of retinal microangiopathy in hypertensive patients. Initially, 254 patients were examined in a cross-sectional study. Following an ophthalmological examination, retinal hemodynamics were quantified by means of video-fluorescence angiography. Moreover, blood fluidity (hematocrit, plasma viscosity and erythrocyte aggregation) was analyzed. The severity of the retinal changes was defined according to the Neubauer classification. One hundred (40%) patients showed retinal changes corresponding to stage I; 133 (52%) were classified as stage II. Hypertensive retinopathy (stage III and IV) was encountered in 20 (8%) patients. Arm-retina time was significant prolonged among the hypertensive patients compared with a control group. Arteriovenous passage time showed no significant differences between hypertensive patients and reference values. Plasma viscosity was significantly increased in hypertensive patients and showed a significant increase with progression of the retinal changes. Hematocrit and erythrocyte aggregation were normal among the patients studied. The present findings show an alteration in blood fluidity among hypertensive patients, whereas retinal microcirculation showed no significant disturbances. Follow-up studies are planned to assess the development of retinal microcirculatory changes among hypertensive patients.

Osteocalcin in patients with rheumatoid arthritis--effect of anatomical stages, inflammatory activity and therapy

The aim of this study was to investigate whether the degree of inflammatory activity, the anatomical stage and various treatments have an influence on bone turnover in patients with rheumatoid arthritis (RA). Osteocalcin (OC) and other parameters of bone turnover were measured in 131 patients with RA. The mean values of alkaline phosphatase (AP), but not of OC were significantly (P < 0.01) higher in our patients compared to controls. In contrast to AP, OC values increased and correlated significantly (r = +0.33, P < 0.01) with ascending anatomical stage in women not on glucocorticoid treatment. As regards therapy, we found significantly lower OC levels in women receiving steroids compared to controls (P < 0.03) and those being treated with non-steroidal anti-inflammatory drugs (NSAIDs) (P < 0.03), methotrexate (MTX) (P < 0.05), or gold (P < 0.01). Females treated with gold had higher OC levels than patients receiving no antirheumatic drugs (P < 0.03). Furthermore, there was a significantly negative correlation between OC and inflammatory activity [C-reactive protein (CRP)] (r = -0.25, P < 0.003). In conclusion, OC levels were significantly higher (P < 0.032) in patients with advanced (anatomical) stages of RA. In contrast to AP, changes in bone turnover, such as suppression of bone formation by steroids and high inflammatory activity in patients with RA, were easily detected.

Secondary hyperparathyroidism and sonographic evaluation of parathyroid gland hyperplasia in dialysis patients

Ninety-six hemodialysis patients were examined by ultrasonography of the parathyroid glands to study the prevalence of parathyroid gland hyperplasia and to assess the relevance of sonography in the evaluation of secondary hyperparathyroidism. The results were compared with clinical, biochemical and radiological parameters. Thirty-two (33.3%) patients had sonographically enlarged glands. Of them 19 had 1 and 13 had 2 and more enlarged glands. Patients with enlarged glands, compared to those with undetected glands, had a significantly higher frequency of bone and joint pains (65.5% vs 40.6%), radiological features of hyperparathyroid bone disease (in hands 28.1% vs 6.9%, in acromioclavicular joints 37.5% vs 13.6%) and higher levels of intact serum parathyroid hormone (1-84) concentration (52.8 +/- 47.9 pmol/l vs 18.1 +/- 18.0 pmol/l) and serum alkaline phosphatase concentration (260.2 +/- 201.1 U/l vs 129.8 +/- 127.3 U/l). Those with enlarged glands had been on dialysis for a longer period (87.7 +/- 51.0 months vs 62.5 +/- 47.4 months). The severity of secondary hyperparathyroidism increased with the number of enlarged glands. Our study shows that ultrasonography is a useful noninvasive screening method for the evaluation of secondary hyperparathyroidism in patients on hemodialysis and that sonographically enlarged glands may be a measure of the severity of secondary hyperparathyroidism.

Effect of fluoride on aluminum-induced bone disease in rats with renal failure

Aluminum (Al) accumulation in renal failure is an etiological factor in the pathogenesis of low turnover bone disease. Aluminum-induced impairment of mineralization has been related to a reduced extent of active bone-forming surface. The present study investigated the effect of fluoride, a potent stimulator of osteoblast number, on the toxicity of aluminum in rats with renal failure (Nx). Following a large parenteral aluminum load (3.2 mg/kg x day) over a period of nine weeks, bone histomorphometry of vertebral cancellous bone revealed a severe low-turnover osteodystrophy as evidenced by a fall in osteoblastic osteoid surfaces and mineral apposition rates. Concurrent administration of fluoride [20 mg/liter (F20) or 40 mg/liter (F40) supplied with the drinking water] resulted in a significant increase in the number of osteoblasts (Nx+Al+F40 vs. Nx+Al, 33.75 +/- 2.83 vs. 1.81 +/- 0.43 mm-1, P less than 0.001) together with an overall reduced deposition of aluminum in bone (469.3 +/- 24.6 vs. 592.2 +/- 28.3 micrograms/g, P less than 0.01). However, there was an increase in the fraction of osteoid surface exhibiting stainable aluminum at the bone-osteoid interface (70.7 +/- 7.1 vs. 44.3 +/- 6.0%, P less than 0.005). Fluoride-exposed rats accumulated a significantly larger osteoid volume, suggesting an exacerbation of the osteomalacic lesion, and furthermore, dynamic histomorphometric parameters remained depressed. These results indicate that fluoride has a distinct effect on the pattern of aluminum deposition in bone. In addition, fluoride antagonizes the aluminum-induced reduction in osteoblast number but provides no amelioration of the impaired mineralization in aluminum-intoxicated rats. Thus, in this model a decrease in the extent of osteoblast surface does not account for the development of aluminum-related bone disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics and pharmacodynamics of cisapride in patients undergoing hemodialysis

Twenty-two patients who were receiving hemodialysis were studied in three groups of eight subjects each to assess the pharmacokinetics during the dialysis-free interval and during hemodialysis treatment and to assess the pharmacodynamics of cisapride. Cisapride and its metabolite norcisapride were measured by use of HPLC and gas chromatography, respectively. The pharmacodynamic effect of cisapride was measured by means of radionuclide gastric emptying. After a single oral dose of 20 mg the terminal half-life of cisapride was 9.6 +/- 3.3 hours, the volume of distribution was 4.8 +/- 3.3 L/kg, the total oral plasma clearance was 380 +/- 161 ml/min, the area under the curve was 1024 +/- 447 ng.hr/ml (mean +/- SD). Norcisapride only could be detected in the dialysate (0.36 +/- 0.067 mg) and was eliminated by a hemodialysis clearance of 34.7 +/- 7.9 ml/min. Cisapride reduced gastric retention from 77.6% +/- 21.1% to 43.7% +/- 18.2% of maximum filling (40 minutes after meals) and normalized the abnormal gastric emptying time in patients receiving dialysis. Cisapride dosage adjustment or substitution after hemodialysis is not necessary.

Tripotassium dicitrato bismuthate: absorption and urinary excretion of bismuth in patients with normal and impaired renal function

We have investigated the absorption and urinary excretion of tripotassium dicitrato bismuthate during a treatment course of 4 weeks in 7 patients with normal renal function (creatinine clearance 115 +/- 29 ml/min; mean +/- S.D.), in 7 patients with impaired renal function (creatinine clearance = 34 +/- 19 ml/min) and in 4 dialysed patients. Following the first dose of tripotassium dicitrato bismuthate (216 mg bismuth b.d.), and after 2 and 4 weeks of treatment (dialysed patients received only 108 mg/b.d.), plasma and urine concentrations of bismuth were monitored for 2 and 24 h, respectively. After stopping therapy plasma and urine concentrations of bismuth were followed for 4 and 6 weeks, respectively. In all three groups of patients small amounts of bismuth (mean values 0.26 to 0.28% of dose) were rapidly (transient mean peak concentrations between 40 and 134 micrograms/L) reached within about 30 to 40 min, absorbed and plasma levels demonstrated a wide intra- and inter-individual variability. Absorption profiles were not altered during the treatment course; however, the trough plasma concentration of bismuth demonstrated an about 3- to 5-fold accumulation (correlated to creatinine clearance) from about 5 micrograms/L to 15 micrograms/L (normal renal function) or to 20-25 micrograms/L (impaired renal function). Pre-study bismuth levels could be detected within 2 to 4 weeks after stopping therapy in all subjects whereas urinary concentrations were still elevated 6 weeks after the course of treatment. Our results indicate that tripotassium dicitrato bismuthate is absorbed in very low amounts during standard therapy. However, dependent on renal function, accumulation to non-toxic levels does occur during a course of treatment. It appears prudent to halve tripotassium dicitrato bismuthate dosage in patients with severe renal insufficiency (creatinine clearance less than or equal to 20 ml/min) to avoid any possible toxic risks. In such patients monitoring of the plasma bismuth concentration might be helpful, especially if longer or repeated treatment is anticipated.

Hyperaluminaemia in critically ill patients: role of antacid therapy and impaired renal function

A significant rise in serum concentrations of aluminum was demonstrated in 23 patients prophylactically treated with the antacid magaldrate, whereas no increase in serum aluminium was observed in another 26 critically ill patients, in whom the use of antacids was avoided. In parallel, urinary excretion rates of aluminum rose to values close to maximum 72 h after antacid therapy had been started. Hyperaluminaemia was most marked in patients with acute renal failure undergoing continuous haemofiltration, but a significant increment in serum aluminium was also noted in patients with impaired renal function in the predialytic state. In the latter group and in patients with normal renal function there was a significant negative correlation between urinary excretion rates of aluminium and creatinine clearance after 48 h of treatment suggesting an enhancement of gastrointestinal absorption of aluminium in the presence of chronic renal failure. Maximum serum concentrations of aluminium did attain critical values in some patients with acute renal failure, but no overt signs of aluminium toxicity were noted. However, in light of both, possible subtle toxicity and enhanced absorption of aluminium in critically ill patients with renal failure, the prophylactic use of antacids in this setting should be re-evaluated cautiously.

Calcium carbonate as a phosphate binder in dialysis patients: evaluation of an enteric-coated preparation and effect of additional aluminium hydroxide on hyperaluminaemia

Calcium carbonate has been successfully used as a phosphate binder in patients with chronic renal failure; however, a high frequency of hypercalcaemia has been reported. To study the effects of calcium carbonate preparations with different dissolution characteristics on the incidence of this side effect, we conducted a double-blind, crossover trial in 21 patients undergoing chronic haemodialysis. Aluminum hydroxide therapy was replaced with calcium carbonate. The subjects then randomly received either an enteric-coated or a gastric-coated preparation. Calcium carbonate (3.1-3.6 g/d) controlled serum phosphate concentrations as effectively as aluminium hydroxide (2.9 g/d). Concurrently, there was a significant rise in mean serum calcium and a fall in serum concentrations of both parathyroid hormone and osteocalcin, the latter suggesting a decrease in bone turnover. Overall, hypercalcaemic episodes developed in 9 patients (43%) and occurred at a considerable frequency (33 episodes per 100 patient-months) during treatment with the gastric-coated formulation. Following conversion to enteric-coated calcium carbonate (3.6 g/d) patients had fewer occurrences of hypercalcaemia (12 episodes per 100 patient-months, P less than 0.05) and, as compared to the gastric-coated preparation, increases in serum calcium greater than 3.00 mmol/l were not observed at all. Hyperaluminaemia was regressive during therapy with calcium carbonate, but addition of small doses of aluminium hydroxide caused a large rise in serum aluminium concentrations after infusion of desferrioxamine, indicating an enhanced rate of absorption or aberrant compartmentalization of aluminium. We conclude that calcium carbonate can control hyperphosphataemia in dialysis patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of lactate on the absorption and retention of aluminum in the remnant kidney rat model

In previous investigations we found the gastrointestinal absorption of aluminum (Al) to be enhanced in uremic rats and this phenomenon could not be attributed to either calcitriol deficiency or secondary hyperparathyroidism. The purpose of this study was to examine whether carboxyl ligands such as lactate could affect the absorption of A1 in our model and, if so, whether this would impose additional alterations on the A1 absorption in uremia. Uremic rats and controls were studied with single oral loads of either A1 chloride or A1 lactate and, subsequently, urinary A1 excretion was measured for 5 days. Compared with Al chloride, administration of A1 lactate resulted in significantly higher urinary excretion rates of A1 in uremic rats (55.5 +/- 22.7 vs. 27.4 +/- 7.0 micrograms; 2.06 +/- 0.84 vs. 1.01 +/- 0.26 mumol) and in controls (23.6 +/- 8.5 vs. 11.9 +/- 4.3 micrograms; 0.87 +/- 0.31 vs. 0.44 +/- 0.16 mumol). However, with either A1 load the recovery of A1 from urine was substantially higher in uremic animals. In contrast, only in controls was there a more pronounced rise in serum A1 concentrations following ingestion of A1 lactate, whereas in uremic rats this increase had a similar magnitude following A1 chloride and A1 lactate, suggesting a larger apparent volume of distribution of the latter. Adjustment of the pH of the A1 lactate-containing solution to 7.0 or oral administration of sodium lactate together with A1 chloride yielded essentially similar results. These observations indicate that the enhanced intestinal absorption of A1 in uremia is further augmented by lactate regardless of the mixture of hydroxolactato complexes employed.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effect of steroids and chloroquine on the intestinal absorption of aluminium and calcium

In rats with normal renal function the intestinal absorption of aluminium appears to be partly vitamin D dependent. To further characterise the similarities between the absorption of aluminium and calcium we investigated the effects of dihydroxylated vitamin D metabolites, prednisolone, and chloroquine (CQ) in Sprague-Dawley rats with normal or reduced renal function. The latter agents interfere with lysosomal functions and have been reported to reduce the intestinal absorption of calcium, whereas vitamin D metabolites may stimulate the absorption of both aluminium and calcium. To assess the intestinal absorption of aluminium we monitored urinary aluminium excretion and serum aluminium concentrations following an oral load of 410 mumol aluminium. Calcium absorption was calculated from the differences between an orally administered dose of 45calcium and faecal excretion. In vitamin-D-deficient rats cholecalciferol and calcitriol augmented urinary aluminium excretion to a similar degree subsequent to an oral load whereas 24R,25(OH)2D3 was without an apparent effect. In vitamin-D-replete rats with normal renal function CQ (225 mg/kg i.p.; 3 days) as well as prednisolone (25 mg/kg; 7 days) significantly reduced calcium absorption (% dose) (CQ: 39 +/- 5%, prednisolone: 42 +/- 3%, control: 58 +/- 11%). In contrast neither drug reduced urinary aluminium excretion (CQ: 519 +/- 92, prednisolone: 494 +/- 137, control: 469 +/- 187 nmol/5 days) or the postload increase in serum aluminium following oral exposure. When aluminium was administered intravenously recovery of aluminium was comparable between treatment groups and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced deposition of aluminium in trabecular bone of uraemic rats treated with dihydroxylated vitamin D metabolites

The rate of aluminium accumulation in bone may be related to the presence of vitamin D metabolites. The present study investigated the effect of 1,25(OH)2D3 (24 pmol/d s.c.) and 24R,25(OH)2D3 (480 pmol/day), combined or alone, on the deposition of aluminium (119 mumol/kg per day) in bone of uraemic rats during concomitant parenteral administration of aluminium for 9 weeks. Bone histomorphometry of trabecular bone revealed a severe low-turnover osteodystrophy in aluminium-treated uraemic rats, as evidenced by a decrease in osteoblastic osteoid surfaces and mineral apposition rates. 1,25(OH)2D3 as well as 24R,25(OH)2D3 decreased stainable bone aluminium and the aluminium content of trabecular bone and, in parallel, the number of osteoblasts and osteoclasts increased. Additional treatment with one or both vitamin D metabolites 14 days prior to the aluminium load further improved these results. Despite these effects, dynamic histomorphometric parameters remained suppressed and osteoidosis persisted. Serum PTH concentrations were significantly elevated in aluminium-loaded uraemic rats treated with 24R,25(OH)2D3 alone compared to controls. In conclusion, administration of 1,25(OH)2D3 or 24R,25(OH)2D3 reduces the accumulation of aluminium in trabecular bone in uraemic rats and prevents some of its excess toxicity. The mechanism of action may be different for either vitamin D metabolite; however, combined treatment does not result in further reduction of the accumulation rate of aluminium in bone in this model.

[The patella-nail syndrome. Study of 2 families]

The radiological and clinical features of two families with a nail-patella syndrome are described. Our findings emphasize the varying expressivity of the syndrome, which has an autosomal dominant mode of inheritance and a penetrance of 100%. It is important for the radiologist to be aware of the syndrome's stigmata so that renal failure can be detected as early as possible after the diagnosis of skeletal dysplasia.

Pharmacokinetics of ranitidine in patients undergoing haemofiltration

The pharmacokinetics of ranitidine was investigated in 11 patients with acute or end stage renal failure during haemofiltration. Each patient received 50 mg ranitidine i.v. The mean distribution and elimination half lives were 0.13 and 2.57 h, respectively. The total body clearance (CL) and volume of distribution (Vz) were 298 ml.min-1 (5.19 ml.min-1.kg-1) and 1.08 l.kg-1, respectively. About 17.1% of the administered dose was removed by haemofiltration (in approximately 20 l filtrate). Five of the patients still had some urine output and they excreted 0.1 to 11.8% of the dose in urine in 24 h. The haemofiltration clearance was 66.9 ml.min-1 at a filtrate flow rate of 86 ml.min-1, corresponding to a mean sieving coefficient of 0.78 (n = 6). As plasma concentrations were still in an effective range after haemofiltration, dose supplementation is not recommended.

Enhanced gastrointestinal absorption of aluminium in uraemia: time course and effect of vitamin D

The present study examines the time course of aluminium absorption in uraemic rats vs controls and investigates the effect of vitamin D. Following an oral load of 410 mumol aluminium there was a significant increase in the urinary excretion rate of aluminium as early as 60 min in uraemic rats. Compared with controls this increase was significantly greater in uraemic animals and maximum excretion rates (77 +/- 49 vs pre-load 2 +/- 1 nmol Al/h) were achieved after 2 h. When vitamin-D-deficient rats with normal renal function were compared with vitamin-D-replete controls, the latter excreted a significantly greater amount of the oral dose of aluminium in their urine (727 +/- 361 vs 359 +/- 140 nmol Al/5d; P less than 0.02) and the post-load increase in the serum aluminium concentration was more pronounced in the vitamin-D-replete animals. Aluminium administered i.v. resulted in similar urinary aluminium excretion rates in both groups. In uraemic rats, however, regardless of their vitamin D status, administration of 1,25(OH)2D3 had no effect on the amount of urinary aluminium excretion after oral or i.v. loads. These findings suggest that although in rats with normal renal function aluminium absorption appears to be partly vitamin D dependent, 1,25(OH)2D3 does not further augment the enhanced gastrointestinal absorption of aluminium in uraemia.

Enhanced gastrointestinal absorption of aluminum in uremic rats

To investigate the possibility of enhanced gastrointestinal absorption of aluminum in uremia, we measured the urinary aluminum excretion of rats following an oral load of 11 mg aluminum. Rats, in which uremia had been established by the remnant kidney model, excreted 1.5 to 2.2-fold higher amounts of aluminum in their urine over a collection period of five days compared with their controls. Within this period of time up to 0.17 +/- 0.08% of the oral dose of aluminum was recovered in the urine of the uremic animals. Serum concentrations of aluminum were significantly elevated five hours after ingestion of aluminum, but this increase was similar in rats with normal or reduced renal function. Uremic rats excreted significantly less aluminum during the first 24 hours after i.v. administration of 15 micrograms aluminum if the data were corrected for the higher baseline excretion rates. The excretion rate showed a negative correlation with the serum creatinine. Selective parathyroidectomy had no effect on the pattern or amount of urinary aluminum excretion after an oral load in either uremic rats or in rats with normal renal function. We conclude that the gastrointestinal absorption of aluminum is increased in uremic rats, and that parathyroid hormone has no detectable effect on the magnitude of aluminum absorption, regardless of the renal function in this model.

5-Fluorocytosine kinetics in patients with acute renal failure undergoing continuous hemofiltration

The pharmacokinetic disposition of 5-fluorocytosine (5-FC) was studied in 7 patients with acute renal failure undergoing continuous hemofiltration (CH). CH was performed with a high-flux membrane and the average filtration rate (FR) was 16.3 ml/min. Following an intravenous loading dose of 2,500 mg, 5-FC concentrations were measured in plasma and ultrafiltrate. The half-lives of 5-FC were markedly prolonged in all patients, ranging from 15.9 to 37.2 h and longer half-lives corresponded to lower FR. The clearance of 5-FC averaged 97.5% of the FR. Within 48 h, 29-35% of the administered dose was recovered in the ultrafiltrate of 3 patients. The volume of distribution ranged from 0.772 to 0.982 l/kg. We found a linear relationship between the elimination rate constant and the FR, and based on these data, a dosage schedule is proposed regarding the use of 5-FC in patients treated with CH.

Activity of ornithine decarboxylase and creatine kinase in soft and hard tissue of vitamin D-deficient chicks following parenteral application of 1,25-dihydroxyvitamin D3 or 24R,25-dihydroxyvitamin D3

We investigated the stimulation of creatine kinase (CK) and ornithine decarboxylase (ODC) by 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] in doses ranging from 1.625 to 6500 pmol in 4-week-old vitamin D-deficient chicks. Enzyme activities were monitored for 72 h. 1,25(OH)2D3 but not 24R,25(OH)2D3 enhanced the activity of ODC in duodenum and bone. The time course of ODC activity in bone was biphasic, with an increase after 1 h and a higher peak after 24 h. Diaphyses and epiphyses responded equally well after a dose of 6500 pmol. The kidney, liver, and lung showed 1.5-3.8-fold increase in CK activity following 1,25(OH)2D3, reaching a maximum between 3-5 h. However, sustained stimulation of CK activity could still be demonstrated after 72 h, and the 48-h levels in the lung even exceeded the 5-h values. No change of activity of either enzyme was noted in heart and brain after application of 1,25(OH)2D3. There was no coincidence of stimulation of ODC and CK by 1,25(OH)2D3 in the same tissue, and the dose-responsiveness of both enzymes differed considerably. Near maximum activities of ODC were achieved with 19.5 pmol 1,25(OH)2D3 in duodenum and pancreas, while maximum responses of CK occurred in the liver at 195 pmol and in lung and kidney at 6500 pmol. 24R,25(OH)2D3 failed to produce any consistent effects of either enzyme in all tissues examined. These results, particularly the lack of response to 24R,25(OH)2D3, are different from those reported in rats.