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H E Franz

Publications and source records attributed to H E Franz.

At least 19 recordsLinked to original sources
PubMed1994

Expression of a rat renal sodium-dependent dicarboxylate transporter in Xenopus oocytes.

Microinjection of mRNA isolated from rat kidney cortex into Xenopus laevis oocytes resulted in the expression of a Na(+)-dependent dicarboxylate transporter, as detected by uptake measurements with [14C]succinate as substrate. The expressed transporter showed an S-shaped Na(+)-dependence with half-maximal activation at 19-21 mM Na+ and a Hill coefficient between 2 and 3. Endogenous succinate uptake was not Na(+)-dependent. Na(+)-stimulated succinate uptake in mRNA-injected oocytes exhibited a maximum at pH 7.5, whereas endogenous Na(+)-independent transporter was fastest at pH 8.5. The expressed dicarboxylate transporter also differed from the endogenous transporter in its sensitivity to citrate as well as dicarboxylates in trans and cis configurations. The expressed transporter resembled the renal basolateral transporter, especially with respect to affinity for succinate (Km 28 microM), activation by Na+, pH-dependence and substrate specificity. After injection of size-fractionated mRNA, succinate uptake was expressed by mRNA of 2-3 kb. Our results suggest expression of the basolateral Na(+)-dependent dicarboxylate transporter after injection of mRNA from rat kidney into Xenopus oocytes.

Animals↗
PubMed1993

Characterization of p-aminohippurate transport from rat kidney which is expressed after injection of size-selected mRNA into oocytes of Xenopus laevis.

First, the existence of an endogenous p-aminohippurate (PAH) transporter in oocytes of Xenopus laevis was demonstrated. When, however, the oocytes were injected with mRNA from rat kidney cortex, an expressed p-aminohippuric acid (PAH) uptake was seen which differed from the endogenous transporter. Both transport systems are saturated at high PAH concentrations, exhibit trans-stimulation by PAH and are partially inhibited by probenecid. The endogenous transport has a rather low affinity for PAH (Km = 0.57 mM) and is about 50% inhibited by probenecid (one apparent inhibition site with half maximal inhibition at 0.5 mM). The expressed PAH transport has a high affinity for PAH (Km = 60 microM) and can be inhibited 80% by probenecid (two apparent inhibition sites with half maximal inhibitions at 1 microM and 2 mM). Expression experiments with fractionated mRNA revealed that the PAH transport expressed from rat kidney cortex is encoded by an mRNA of 1.8 to 2.5 kb.

Animals↗
PubMed1993

Evidence that functional deletion of donor-reactive T lymphocytes in kidney allograft recipients can occur at the level of cytotoxic T cells, IL-2-producing T cells, or both. A limiting dilution study.

The frequencies of circulating donor-reactive cytotoxic lymphocyte precursors (CLP) and Il-2-producing helper lymphocyte precursors (HLP) were determined by limiting dilution analysis in 19 kidney allograft recipients before and at various intervals (up to 2 years) after transplantation. A significant, selective, and stable reduction of the frequencies of donor-reactive (but not of third party-reactive) CLP and/or HLP was observed in some patients beginning 3 to 6 months after transplantation. One patient developed reduced frequency of CLP only, 3 patients reduced frequencies of HLP only, and 2 patients reduced frequencies of both CLP and HLP. The selective reduction of donor-reactive CLP and/or HLP frequencies ranged from 5-25-fold when compared with the pretransplantation level and was associated with stable graft function. These data indicate that functional deletion of circulating donor-reactive T cells can occur at the level of cytotoxic T lymphocytes, Il-2-producing helper T lymphocytes, or both. Implications of these findings for the individualization of immunosuppressive regimens will be discussed.

Humans↗
PubMed1992

[LDL cholesterol apheresis by adsorption to dextran sulfate].

Extracorporeal LDL cholesterol elimination may be the sole successful treatment in familial hypercholesterolemia. By treatment of 41 plasma both total cholesterol and LDL cholesterol were lowered by 69 +/- 1% and 78 +/- 1%, respectively. HDL cholesterol was decreased by 24 +/- 3%. This could be explained both by hemodilution (hematocrit was decreased by 9.3 +/- 2.8%) and unspecific adsorption of various plasma proteins (-15.3 +/- 3.7 g/l, i.e. -22 +/- 4%). Protein electrophoresis showed different affinities of the protein fractions. These data suggest that LDL apheresis by dextran sulfate is an effective method for the elimination of LDL cholesterol. However, other proteins besides apolipoprotein B are adsorbed to dextran sulfate.

Adsorption↗
PubMed1991

Clearance of osteocalcin in adults with end-stage renal disease undergoing CAPD.

Osteocalcin (OC) is a bone-specific protein whose blood concentration is a specific and sensitive marker of bone turnover. In adults undergoing continuous ambulatory peritoneal dialysis (CAPD), mean serum osteocalcin levels (S-OC) are lower than in similar patients on hemodialysis. We therefore measured the serum (S) and dialysate (D) levels of OC, estimated the peritoneal clearance (Cp) and mass transfer (MT) of OC and evaluated the relationship between S-OC levels and other serum biochemical parameters of bone metabolisms. Fourteen adult patients on CAPD were studied with a mean age of 46.3 +/- 13 years and a mean dialytic age on CAPD of 17.4 +/- 9.6 months. OC concentrations in (S) and (D) were 60.8 +/- 55.5 micrograms/l (normal range: 4.3-12.4 micrograms/l) and 6.9 +/- 6.2 micrograms/l, respectively. The Cp of OC was 1.08 +/- 0.3 ml/min and the MT of OC over 4-h dialysis exchange periods was 14.5 +/- 12.3 micrograms when using a dialysis solution containing 2.27% glucose. S-OC was significantly correlated with serum levels of alkaline phosphatase (r = 0.80), intact PTH (r = 0.82) and the MT of OC (r = 0.94). No significant correlations were found with serum levels of total calcium, phosphate, creatinine, total protein and dialytic age. These results suggest that the OC level in serum is influenced by both bone turnover and peritoneal clearance. Therefore, altered serum levels of OC should be interpreted always together with the peritoneal mass transfer of OC. Taking this into account, OC and intact PTH may be of value as markers of increased bone turnover secondary to renal osteodystrophy in CAPD.

Adult↗
PubMed1988

The influence of kidney transplantation on carnitine metabolism.

In this study, we examined all three plasma carnitine fractions, free carnitine (FC), short-chain acyl- (SCC), and long-chain acylcarnitine (LCC), as well as the urinary excretion of FC and SCC in 62 patients with functioning renal allografts 1-70 months following the kidney transplantation (KT). Patients were classified into three groups according to their transplant function, as characterized by the serum creatinine concentration (CR). A comparison with normal subjects (n = 20) and with patients on chronic hemodialysis (HD, n = 46) revealed a complete normalization of all carnitine plasma fractions for group I patients (Cr less than 120 mumol/l). In contrast, significant elevations of plasma free and esterified carnitine were found in group II (Cr greater than 120, less than 200 mumol/l; with FC + 27%, SCC + 82%, and LCC + 49% and group III patients (Cr greater than 200 mumol/l; with FC + 39%, SCC + 122%, and LCC + 106%), as compared to healthy subjects (p less than 0.001). The elevations in concentrations of SCC were more pronounced than those of FC; consequently, we found a higher ratio of acylcarnitine (AC) to FC in group III than in group I patients (+ 41%, p less than 0.001). Yet even in the former group, this ratio was found to be markedly reduced when compared to HD patients (-41%, p less than 0.001). We found no significant differences in the urinary excretion of FC and SCC between the 3 groups of KT patients. It is thus to conclude that in patients with a well-functioning transplant, the pattern of carnitine fractions in plasma is fully normalized. The decrease in the ratio of AC to FC following a successful KT might suggest a better availability of FC and thereby be associated with an enhanced fatty acid oxidation.

Acetylcarnitine↗
PubMed1987

Selective reduction of donor-specific cytotoxic T lymphocyte precursors in patients with a well-functioning kidney allograft.

We have recently developed a sensitive limiting dilution (LD) culture system to measure human alloreactive cytotoxic T lymphocyte precursors (CTL-p) in a given lymphoid cell population. We have now used this system to determine frequencies of donor HLA antigen-inducible CTL-p in the peripheral blood of human allograft recipients at various stages after transplantation. All patients (1 pancreas recipient and 9 kidney recipients) were on continuous cyclosporine treatment throughout the study. We report that, in patients with a well-functioning kidney graft (6/9), the number of donor-reactive CTL-p among peripheral blood lymphocytes decreased within 3-8 months after transplantation--in some cases (2/6) more than 10-fold. In contrast, frequencies of CTL-p with specificity for third-part HLA antigens remained largely unaltered in these patients. Furthermore, no decrease of donor-reactive CTL-p frequencies was seen in 3 of 4 patients showing clinical symptoms of graft rejection. These results indicate that functional clonal deletion of antigraft-reactive CTL-p may contribute to the state of graft tolerance in certain patients with a well-functioning kidney allograft.

Cells, Cultured↗
PubMed1986

Isosorbide dinitrate in plasma and dialysate during haemodialysis.

In 10 patients with end stage renal disease on regular haemodialysis the plasma concentrations and dialyzer clearance of isosorbide dinitrate (ISDN) were determined after an oral dose of a retarded release formulation of 60 mg ISDN. The maximal plasma concentration of ISDN 2-7 h after oral administration was higher (14 ng/ml) than has been reported in healthy volunteers. The haemodialyzer clearance of ISDN was 92.4 ml/min at a blood flow of 200 ml/min and dialysate flow of 500 ml/min. During a 5-h haemodialysis an average of 0.3 mg ISDN was removed from the patient's circulation, representing about 0.5% of the administered dose and about 3% of the available drug in the circulation. No influence of haemodialysis on the plasma level of ISDN was found.

Aged↗
PubMed1986

Real-time ultrasound evaluation of renal transplant failure during the early postoperative period.

In a prospective clinical trial 385 ultrasound (US) examinations were performed on 50 renal allograft patients. Baseline sonograms were obtained within 24 hrs of transplantation, and serial US examinations were performed in two to three days intervals during hospital recovery. 24 out of 28 cases of acute rejections (85.7%) were detected by US with an 8% false positive rate. Using statistical analysis, enlarged and sonolucent pyramids, areas of decreased parenchymal echogenicity and an increase in anterior-posterior diameter of the organ, proved to be the best US-rejection criteria. Fine needle aspiration cytology revealed a high rate of false positive rejection diagnosis (23.8%). The results demonstrate that US is a valuable diagnostic aid in the evaluation of postoperative renal transplant failure.

Adult↗
PubMed1985

[Ultrasonically targetted fine-needle aspiration cytology in the immediate postoperative follow-up of transplanted kidneys].

From March 1982 to September 1983 62 ultrasound-guided fine needle aspiration cytologies in 22 patients with cadaveric kidney transplants had been performed during the postoperative hospitalisation period. In any case it was possible to guide the needle tip into the cortico-medullary boundary or in sonolucent parenchymal areas occurring during acute cellular rejection episodes. Thus technical failures could be reduced to 6% (4 out of 22). In 79% the clinically suspected diagnosis could be confirmed by FNAC. Aspirates from circumscript sonolucent parenchymal areas allowed rejection diagnosis in 95%. In 17% cellular signs of rejection were seen cytologically despite a regular transplant function.

Adult↗