Diurnal alteration of platelet-free Ca2+ in subjects with normal renal function and patients undergoing CAPD]

We examined the relation of diurnal alteration of platelet-free Ca2+ to blood pressure and plasma vasoactive substances in 6 subjects with normal renal function (N group) (with both normal GFR and normal urine concentration, and with the renal biopsy finding of minor glomerular change) and 7 patients undergoing CAPD (CAPD group), then evaluated the pathophysiological difference in diurnal variations between both groups and the effect of native kidney function. Diurnal values of platelet basal-free Ca2+ concentration in N showed a positive correlation with the corresponding PRA levels. On the other hand, in CAPD they showed a positive correlation with the corresponding levels of plasma AVP. The larger increases in platelet-free Ca2+ concentration due to thrombin stimulation were observed in the daytime and the smaller increases in the nighttime in the N groups. The thrombin-induced changes showed a positive correlation with the diurnal levels of mean blood pressure in N (p < 0.004). However, in contrast, in CAPD the increase in platelet-free Ca2+ due to thrombin tended to be larger in the nighttime and showed a negative correlation with the daily mean blood pressure levels (p < 0.004). These findings suggest that there might be differences in the regulation of intracellular-free Ca2+ dynamics and the diurnal variation between subjects with normal renal function and patients undergoing CAPD. Those differences could affect the progression of vascular disturbance in CAPD patients.     

Furosemide disposition in patients on CAPD

Single doses of oral and intravenous furosemide were given to 8 healthy male volunteers (40 mg) and 11 patients with renal failure maintained on continuous ambulatory peritoneal dialysis (CAPD) (80 mg). In the volunteers, absorption was variable. Only one half of the intravenous dose and one third of the oral dose was available for renal pharmacological action as judged by the urinary recovery. In the patients, absorption was also variable and was markedly delayed (tmax 128 vs 90 min) but more complete (bioavailability 70.1 vs 53.6%). The differences between the two groups were not significant, however (95% C.I.: -90 to 30 and -40.4 to 7.5 respectively). The mean elimination half-life was significantly longer in the patients following both the oral (228 vs 65.1 min) and intravenous dose (195 vs 60.3 min). The total body clearance of furosemide in the volunteers was 138 ml x min(-1) and this was much lower in the CAPD patients (61.9 ml x min(-1)) in whom the renal clearance was negligible. Although there were trends indicating differences in absorption between the two groups, the significant differences in furosemide disposition observed in CAPD patients were due to renal failure.     

Diurnal and long-term variations of lymph capillary pressure in healthy subjects

The practical value of the detection of clonality within the T-cell receptor gamma locus by polymerase chain reaction for the diagnosis of cutaneous T-cell lymphomas is well known. However, studies dealing with this subject so far, with special emphasis on the sensitivity of the technique in comparison to, for example, Southern blotting have used mixtures of DNA in various concentrations instead of using mixtures of the cells involved, which would reflect the in vivo situation in a more realistic scope. The purpose of this study was therefore to determine the sensitivity and the limitations of the PCR assay by dilution experiments, using mixtures of cells. Furthermore we studied its applicability to cutaneous T-cell proliferative disorders. Two clonal T-cell lines (MyLa and Jurkat) served as positive control. Dilutions of MyLa cells, cultured normal human keratinocytes and peripheral blood mononuclear cells from lymphoma negative volunteers were used to assess the sensitivity of the PCR-DGGE assay. Skin samples from 4 patients with cutaneous T-cell lymphoma, 1 lesional lymph node, 2 blood samples from a patient with Sézary syndrome and 4 lymphoma-negative tissue samples were analysed. Two samples were uncertain for diagnosis of lymphoma. The PCR-DGGE assay consisted of a 2-round nested PCR with consensus primers within the TCR-gamma locus followed by electrophoretic separation of the product along a denaturing urea/formamide gradient gel. PCR-DGGE sensitivity was, to our knowledge, for the first time investigated for mixtures of lymphocytes (clonal and polyclonal) and keratinocytes. Clonal T-cells were detected in a concentration between 1-0.1% in keratinocytes, whereas the sensitivity was generally lower upon dilution in peripheral blood mononuclear cells or in a mixture of keratinocytes and peripheral blood mononuclear cells. Nevertheless, T-cell clonality was detected in 2 blood samples of a patient with Sézary syndrome, which were negative by Southern blot analysis. The crucial point of this work was the new approach to establish the sensitivity of the PCR-DGGE, in a way which more closely mimics the condition of clinical specimens. Instead of mixing and amplifying DNA extracted from clonal T-cell lines and polyclonal bone marrow cells, we amplified DNA from clonal and polyclonal cells which had been mixed in various ratios before DNA extraction. Polymerase chain reaction in conjunction with denaturing gradient gel electrophoresis is a sensitive and versatile molecular tool for the assessment of clonality of suspect cutaneous lesions. The determination of sensitivity using DNA extracted from premixed cells more closely corresponds to the actual test situation when testing skin samples.     

Diurnal variations in the urinary excretion of calcium and phosphate in hyperparathyroidism

The urinary excretion of calcium and phosphate during the day and night was studied in 20 patients with primary hyperparathyroidism and in the same number of controls with normal function of the parathyroids. A significant difference in TRP between day and night was found in the controls but not in the HPT group. In other respects there were no substantial differences between day and night. The higher excretion of calcium observed in the HPT group was largely attributable to the patients with remal calculi. The simplified sampling procedure when only night urine is analysed has no disadvantages-it is more likely to improve the diagnostic reliability as it reduces the influence of meals, for example.     

Incidence of and risk factors for hepatitis B virus and hepatitis C virus infection among haemodialysis and CAPD patients: evidence for environmental transmission

Hepatitis B virus (HBV) serum markers (HBsAg, anti-HBs, anti-HBc) and antihepatitis C antibody (anti-HCV) were prospectively followed in haemodialysis and CAPD patients. From January 1987 to January 1990, 185 patients on haemodialysis and 124 on CAPD were analysed. Among patients susceptible to HBV (69 on haemodialysis and 70 on CAPD), there were 17 HBsAg seroconversions on haemodialysis (0.19/patient-year) and 1 on CAPD (0.01/patient-year). A Cox proportional hazards model showed that haemodialysis treatment was the only risk factor significantly associated with HBV infection, thus suggesting transmission through the environment. Regarding hepatitis C, 83 anti-HCV-negative patients on haemodialysis and 46 on CAPD were followed. There were 18 seroconversions on haemodialysis (0.15/patient-year) and two seroconversions on CAPD (0.03/patient-year). Haemodialysis treatment was also the only risk factor significantly associated with a higher risk of HCV infection. The hazard ratio for HCV infection in haemodialysis patients was 5.7 compared to CAPD patients. Nevertheless, for one patient on CAPD treatment transfusions were the only possible source of HCV infection. In conclusion, both viruses were transmitted mainly through the haemodialysis environment, but the role of transfusions could not be excluded.     

Silicon and aluminium interactions in haemodialysis patients

BACKGROUND: Aluminium toxicity in dialysis patients is well described. Aluminium has a close chemical affinity with silicon. Silicon may have a role in protection against aluminium toxicity. METHODS: We measured serum aluminium and silicon levels from haemodialysis patients from four different centres. RESULTS: Though no relationship was seen across all centres combined, in one centre there was a reciprocal relationship in patients on home haemodialysis (who did not require reverse osmosis). Median (range) aluminium levels were higher, 2.2 (0.4-9.6) micromol/l when serum silicon was less than 150 micromol/l, and lower, 1.1 (0.2-2.8) micromol/l when serum silicon levels were greater than 150 micromol/l (P = 0.03). CONCLUSIONS: In patients treated by haemodialysis without reverse osmosis high serum silicon concentrations were associated with lower serum aluminium concentrations than those with low serum silicon. Further work needs to confirm a preventative role for silicon in the accumulation and subsequent toxicity of aluminium in dialysis patients.     

A study on angiotensin-I converting enzyme polymorphism in CAPD patients

To clarify the role of genes related to angiotensin-I converting enzyme (ACE), the author investigated polymorphism of the ACE gene in 60 patients undergoing chronic ambulatory peritoneal dialysis (CAPD) and 50 patients undergoing hemodialysis (HD). One hundred healthy subjects were used as controls. The polymorphism was classified into three genotypes, II, ID and DD, according to insertion (I) and deletion (D) using the polymerase chain reaction method. In dialysis patients (CAPD or HD, n = 110), 21.8% had the II genotype, 48.2% the ID genotype, and 30.0% the DD genotype. There was a significant difference in allele frequency between normal subjects (n = 100) (J = 0.63, D = 0.37) and dialysis patients (I = 0.46, D = 0.54) (chi 2 = 12.321, p < 0.001). The mean plasma ACE activity was 9.9 +/- 1.6 IU/l in CAPD patients with the II genotype, 11.6 +/- 4.7 IU/l in CAPD patients with the ID genotype, and 14.5 +/- 3.5 IU/l in CAPD patients with the DD genotype. The mean rate of decrease in residual urinary volume was 0.8 +/- 0.7% per month in CAPD patients with the II genotype 1.4 +/- 1.3% per month in CAPD patients with the ID genotype, and 2.5 +/- 2.0% per month in CAPD patients with the DD genotype. These data showed a significant decrease in urinary volume in CAPD patients with the DD genotype (p < 0.05). The mean rate of decrease in residual urinary volume was positively correlated with the plasma ACE activity (r = 0.13389, p < 0.02). In CAPD patients, the mean cardiothoracic ratio was 46.6 +/- 3.5% in cases with the II genotype, 47.6 +/- 5.5% in cases with the ID genotype, and 52.9 +/- 8.4% in cases with the DD genotype. These data indicated significant cardiac enlargement in DD genotype cases. It can be concluded that CAPD patients with the DD genotype lost their residual renal function more rapidly and had a larger heart, than patients with the other genotypes.     

High-dose alfacalcidol improves anaemia in patients on haemodialysis

BACKGROUND: Alfacalcidol is efficient for treating secondary hyperparathyroidism in patients on maintenance haemodialysis (HD). Little is known about the direct impact of high-dose alfacalcidol on anaemia in end-stage renal failure. We therefore carried out a prospective study over 18 months to examine the direct effect of high-dose alfacalcidol on erythropoiesis in erythropoietin (rHuEpo)-dependent anaemic patients on HD for more than 6 months with moderate hyperparathyroidism. STUDY DESIGN: Twelve patients received oral alfacalcidol at a dosage of 6-7 micrograms per week and calcium carbonate during the first 12 months, calcium carbonate without alfacalcidol during the next 3 months, and again alfacalcidol and calcium carbonate during the last 3 months. Criteria for selection were haemoglobin < 10 g/dl, iPTH > 250 pg/ml, transferrin saturation (TS) > 25%, S-ferritin > 300 micrograms/l, and S-aluminium < 40 micrograms/l. RESULTS: Haemoglobin (Hb) and reticulocyte counts increased during the first phase, decreased and returned to a baseline prior to starting vitamin D treatment in the second phase, and again increased when alfacalcidol was reintroduced, whereas iPTH decreased during the first 3 months of the first phase and then remained stable, as did S-calcium, which increased during the first 3 months and then remained constant. S-phosphate increased during the first and third phases, and decreased during the second phase. Two patients during the first phase and one patient during the third phase presented hypercalcaemia; requiring a temporary discontinuation of alfacalcidol. CONCLUSION: High-dose alfacalcidol is efficient in anaemic patients with moderate hyperparathyroidism on maintenance HD and has a direct effect on erythropoietic cells regardless of serum calcium and iPTH levels.     

Hernia development in CAPD patients and the effect of 2.5 l dialysate volume in selected patients

Merkel cell carcinoma (MCC) of the skin is a rare, primary malignant skin neoplasm which can present as a cutaneous nodule. These neoplasms are seen primarily in the elderly and located in the head and neck area or extremities. Twenty-nine aspirates from primary and metastatic lesions obtained by percutaneous fine-needle aspiration in 19 patients have been studied. The cytomorphologic features, clinical information, and immunocytochemical (ICC) findings are detailed. Aspirate smears demonstrated small-to-intermediate-sized cells with a loosely cohesive pattern. Nuclei were round with finely granular chromatin and multiple, small nucleoli. Cells possessed a thin rim of cytoplasm, and infrequent pseudorosette formations were noted in cell groups. ICC results were universally positive for cytokeratin, which showed a paranuclear "dot-like" pattern. Neuron-specific enolase, epithelial membrane antigen, and S-100 protein were positive in varying degrees. Leukocyte common antigen was universally negative. The diagnosis of MCC of the skin by FNA can be made by applying cytologic features in addition to ancillary studies and clinical information.     

Diurnal variations in vasoactive intestinal polypeptide-like immunoreactivity in the suprachiasmatic nucleus of congenitally anophthalmic mice

The present study has combined recording of circadian locomotor rhythms with light microscopic immunocytochemistry for vasoactive intestinal polypeptide (VIP) in the suprachiasmatic nucleus (SCN) of congenitally anophthalmic mice. These mice, which never develop retinae or optic nerves and do not perceive light, are thus in constant darkness. Our data show a circadian rhythm in expression of VIP in the SCN of anophthalmic mice--expression is maximal during late subjective night/early subjective day and minimal in late subjective day/early subjective night. These observations support the hypothesis that expression of VIP is related to regulation of circadian rhythms by the SCN.