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Biomedical subjects

F Reutter

Publications and source records attributed to F Reutter.

At least 19 recordsLinked to original sources

Immunostimulants and Toll-like receptor ligands obtained by screening combinatorial lipopeptide collections.

Synthetic lipopeptides carrying the head group of bacterial lipoproteins are specific ligands of Toll-like receptors (TLR). The three fatty acids containing lipopeptides with the tripalmitoyl-S-glyceryl-cysteinyl N-terminus (Pam(3)Cys) are agonists of TLR2. The structurally related lipopeptides with a head group lacking the fatty acyl residue at the amino-terminus (Pam(2)Cys) stimulate TLR2 and 6. To investigate the influence of the peptide chain of lipohexapeptides with a free N-terminus with regard to their ability to enhance B-cell proliferation, a randomized S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteinyl-pentapeptide amide collection Pam(2)CysXXXXX and 5 x 19 subcollections (Pam(2)CysOXXXX, Pam(2)CysXOXXX, Pam(2)CysXXOXX, Pam(2)CysXXXOX, Pam(2)CysXXXXO, O: all protein amino acids except Cys) were prepared by parallel solid-phase synthesis. The collection represents synthetic lipopeptide analogues of the numerous bacterial lipoproteins and of mycoplasma lipoprotein. Each of the 95 subcollections is characterized by one defined and four degenerated amino acid positions thus comprising 19(4) individual lipopeptides with free N-terminal amino groups. High-performance liquid chromatography electrospray mass spectrometry (HPLC-ESI-MS) was applied for the analytical characterization of the lipohexapeptide amide subcollections and for the individual lipohexapeptide amides. The subcollections were tested for polyclonal activation of murine spleen cells, deconvolution led to highly active single S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteinyl-pentapeptide amides.

Adjuvants, Immunologic↗

Single-injection inulin clearance for routine measurement of glomerular filtration rate in cats.

Glomerular filtration rate (GFR) was determined in 53 cats using an inulin single-injection method. Thirty healthy young adult cats were used to establish normal values. The procedure was also used in 23 cats that were either older than 10 years or had borderline serum creatinine levels. The total clearance was calculated from the decay of the serum inulin concentration after injection of 3000 mg/m(2)body surface area using a two-compartment model. Concomitant inulin and iohexol clearance in nine cats showed excellent correlation between the two methods. Calculated normal values for GFR in 30 healthy cats were 35.9-58.5 (median 46.0) ml/min/m(2)or 2.07-3.69 (median 2.72) ml/min/kg. A few cats with normal creatinine or blood urea nitrogen levels were detected as having reduced GFR and therefore being in a state of early renal dysfunction. The study indicates that single-injection inulin clearance is a valuable tool for routine GFR measurement in cats. An "inulin excretion test" using only one blood sample 3h after the administration of 3000 mg/m(2)body surface area could prove an attractive alternative for the assessment of renal function in daily practice.

Animals↗

Generation of 8-epi-prostaglandin F(2alpha) in isolated rat kidney glomeruli by a radical-independent mechanism.

Isoprostanes comprise a group of free radical-catalyzed products of arachidonic acid. However, there is recent evidence pointing towards an enzyme-dependent formation of isoprostanes. With the use of isolated rat glomeruli we addressed the mechanisms of isoprostane generation. Synthesis of prostanoids and isoprostanes, including 8-epi-PGF(2alpha), was studied under conditions favouring radical formation. Cultured glomeruli formed different prostanoids including 8-epi-PGF(2alpha). Upon LPS challenge cyclo-oxygenase (COX)-2 expression was enhanced, and this was paralleled by a 2 - 9-fold increase in prostanoid formation, including isoprostanes. Addition of COX-isoform unselective inhibitors (diclofenac, indomethacin) or a selective inhibitor (NS-398) suppressed the synthesis of prostanoids, 8-epi-PGF(2alpha) and total isoprostane fraction; however, inhibition of the latter was less pronounced. Antioxidants such as butylated hydroxytoluene (BHT), nordihydroguaiaretic acid (NDGA), or dimethylurea exhibited an only minimal inhibitory effect on 8-epi-PGF(2alpha) synthesis. Moreover, ROS-generating drugs (menadione, methylviologen) or NADPH-driven radical formation were unable to cause the generation of significant amounts of 8-epi-PGF(2alpha) by rat glomeruli. In contrast, the total isoprostane fraction could be increased by menadione addition. These data provide further evidence for a radical-independent, but COX-dependent formation of 8-epi-PGF(2alpha) in renal tissue. Regarding the other isoprostanes, both radicals and COX enzymes contribute to their formation. Based on our data we assume that elevated release of vasoactive 8-epi-PGF(2alpha) has to be expected under conditions when the prostanoid system in the kidney is stimulated, e.g. under inflammatory conditions. Regarding renal oxidative injuries, the usefulness of 8-epi-PGF(2alpha) as a representative marker molecule of oxidative stress has to be questioned.

Animals↗

Generation of the isoprostane 8-epi-prostaglandin F2alpha in vitro and in vivo via the cyclooxygenases.

F2-isoprostanes are isomers of the prostaglandin PGF2alpha. At least one compound of this group, 8-epi-PGF2alpha, exhibits biological activity, and therefore special interest is focused on the mechanism of isoprostane formation: enzyme catalyzed or radical mediated. We analyzed the formation of isoprostanes in vitro and in vivo. In both systems, purified cyclooxygenase isoenzymes and cell models specific for the cyclooxygenase isoenzymes, 8-epi-PGF2alpha formation could be totally suppressed by cyclooxygenase inhibitors. Indomethacin inhibited concentration-dependent 8-epi-PGF2alpha formation in platelets stimulated with calcium ionophore, arachidonic acid or thrombin. Nordihydroguaiaretic acid, an antioxidant, blocked isoprostane formation with a similar IC50 value as thromboxane B2 synthesis, pointing toward cyclooxygenase as the primary target of inhibition. Based on the turnover number, cyclooxygenase-2 formed higher levels of 8-epi-PGF2alpha than cyclooxygenase-1. Endogenous 8-epi-PGF2alpha production in rat mesangial cells correlated well with the mRNA and protein expression of cyclooxygenase-2 during interleukin-1 induction. However, in contrast to human platelets, which produced different forms of isoprostanes, rat mesangial cells appeared to form only 8-epi-PGF2alpha. Further, this indicates that mesangial cells may represent a cellular origin for renal 8-epi-PGF2alpha formation. Next, we analyzed the formation of isoprostanes in humans. A direct correlation was observed between indomethacin treatment and the decrease in 8-epi-PGF2alpha and isoprostane levels, but compared with other prostanoids the inhibition was less pronounced. In summary, based on the in vitro studies, a clear cyclooxygenase-dependent formation of isoprostanes, especially 8-epi-PGF2alpha, was observed. However, in vivo additional formation via cyclooxygenase enzyme-independent mechanisms is likely.

Adolescent↗

[Pravastatin in the treatment of primary hypercholesterolemia: a Swiss multicenter study].

Conventional lipid-lowering agents displayed only limited efficacy in lowering total and LDL cholesterol and a high incidence of side effects. Pravastatin is a new potent cholesterol-lowering agent, which selectively inhibits hepatic HMG-CoA-reductase. In a double-blind, placebo-controlled Swiss multicenter study with determination of lipids and lipoprotein in a central laboratory, the efficacy and safety of 6 months' therapy with pravastatin was evaluated in 50 patients with mild hypercholesterolemia and additional coronary risk factors. Compared to baseline and after 26 weeks' therapy, pravastatin significantly reduced total cholesterol (pravastatin vs placebo, -17% vs +7%, p < 0.0001) and LDL cholesterol (-26 vs +2%, p < 0.0001). The total/HDL cholesterol ratio ( = "atherogenic index") was comparable in the two groups at baseline (5.9 +/- 1.1 vs 6.3 +/- 0.9), and was distinctly lowered by pravastatin but not placebo (-20 vs 0%, p < 0.0001). In 11 patients in whom the reduction of serum total cholesterol after 13 weeks' treatment with 20 mg pravastatin was still below target (on average -9.1%), doubling of the dose produced a further decrease of 4.3%. Serum HDL cholesterol and serum triglyceride levels did not change significantly during pravastatin treatment as compared to baseline and placebo. Pravastatin was well tolerated during the 26 weeks without relevant subjective side-effects. There were 5 dropouts during the study, 2 patients in the pravastatin group and 3 in the placebo group. These findings document that pravastatin, administered in a single daily dose of 20 to 40 mg, effectively lowers serum cholesterol and total-/HDL-cholesterol improving action and is well tolerated.

Cholesterol, HDL↗

[Blood pressure lowering action and tolerance of ketanserin in mono- or combination therapy].

The antihypertensive efficacy and tolerability of the 5HT2-receptor antagonist ketanserin was investigated in 188 patients aged 41 to 82 years with mild to moderate essential hypertension. Ketanserin was given as monotherapy (n = 107) as well as in combination with either the diuretic hydrochlorothiazide/amiloride (n = 42) or the betablocker atenolol (n = 39) for 12 weeks. Compared to placebo, ketanserin lowered systolic blood pressure by 11 +/- 16 (SD), 9 +/- 13 and 9 +/- 11 mm Hg (p less than 0.01 for all) and diastolic blood pressure by 9 +/- 10, 10 +/- 9 and 7 +/- 9 mm Hg (p less than 0.001 for all), in the three treatment groups; body weight, serum sodium, potassium, uric acid, cholesterol and triglycerides remained unchanged. The incidence of withdrawals due to unwanted effects was 4% on ketanserin monotherapy, and 12% and 10% on the diuretic/ketanserin and the betablocker/ketanserin combination respectively. Well-being during ketanserin therapy was improved in the older patients in particular; sleep disturbances, daytime fatigue and overall weakness decreased. Ketanserin was well tolerated in combination with the diuretic, whereas in combination with the betablocker the occurrence of dry mouth and stuffy nose was slightly higher. - Ketanserin proved to be an effective antihypertensive drug comparable to other blood pressure lowering agents. It can be combined advantageously with a potassium sparing diuretic or a betablocker. The greater efficacy and tolerability in patients greater than or equal to 60 years qualify ketanserin primarily as an antihypertensive agent for older patients.

Adult↗

MRI in Cockayne syndrome type I.

MRI findings are reported from two patients with Cockayne syndrome (CS) type I, aged 11 and 37 years. Changes were compatible with diffuse white matter hypomyelination. Basal ganglia calcification was present in both, marked cerebellar atrophy in the older patient. MRI may support the diagnosis of CS in the appropriate clinical context. The view that CS is a dysmyelinating disorder is further substantiated.

Adult↗

Antihypertensive efficacy and well-being during monotherapy and combination therapy with ketanserin.

The effects of ketanserin on blood pressure and well-being were investigated in 188 patients, aged 41-82 years, with mild to moderate essential hypertension. At entry, 107 were untreated, 42 were taking the diuretic combination hydrochlorothiazide (50 mg/day) plus amiloride (5 mg/day) and another 39 were taking the beta-blocker atenolol (100 mg/day). A single-blind, 4-week placebo run-in period was followed by 12 weeks' oral ketanserin treatment at 20 or 40 mg twice a day. This regimen significantly reduced systolic and diastolic blood pressures in each group. Response rates were greater in patients aged over 60 years. Compared with placebo, sleep disturbances, daytime fatigue and overall weakness decreased during ketanserin treatment (P less than 0.05 for all), but the incidence of dry mouth and stuffy nose increased. In patients older than 60 years there was a greater reduction of complaints than in younger patients. Ketanserin proved effective and well tolerated, improving peripheral circulatory symptomatology, particularly in older patients and those with a good blood pressure response.

Adult↗

[Medullary sponge kidney. Diagnosis and course in 12 cases].

12 adult patients with medullary sponge kidney (MSK), followed up for 1 to 14 years (mean 7 years) are presented. MSK was initially diagnosed in 4 cases. In 8 cases the initial diagnosis included pyelonephritis, nephrocalcinosis, and nephrolithiasis. Renal calculi (4 patients), urinary tract infection (8) and hematuria (5) were the most frequent symptoms. Renal tubular acidosis was documented in 2 patients and hypercalciuria without hyperparathyroidism in 2. Over the years renal calculi increased in size in 4 patients. Renal function was stable in 11. In one patient with associated, well controlled hypertension, serum creatinin rose from 141 to 298 mumol/l over 14 years.

Adult↗

[Focal-segmental glomerulosclerosis in analgesic nephropathy].

The presence and extent of focal-segmental glomerulosclerosis/hyalinosis (FSSH) was determined in 79 autopsy cases of analgesic nephropathy and correlated with the levels of proteinuria, serum creatinine and arterial blood pressure. FSSH was present in 77% of cases. The extent of FSSH correlates positively with increasing proteinuria and serum creatinine. The widely scattered pattern suggests a multifactorial pathogenesis for FSSH in analgesic nephropathy, including, for example, glomerular overload and arterial hypertension. Mesangial proliferative glomerulonephritis was observed in only two cases.

Adult↗

Problem cases in renovascular hypertension.

The clinical course and response to therapy of 16 patients with various complex forms of renovascular hypertension were investigated. Reconstructive surgery and/or transluminal dilatation was either ineffective (n = 5) or could not be performed for technical reasons (n = 11). The group contained 7 patients with multilocular fibromuscular disease involving both renal arteries, two cases with multiple arteriosclerotic vascular occlusions, 3 patients with branch renal artery aneurysms, 3 with renal artery stenosis in a solitary kidney and one patient with renal artery stenosis and contraction of the contralateral kidney due to a non-vascular cause. With antihypertensive treatment, particularly with the angiotensin converting enzyme inhibitor captopril (n = 7), blood pressure could be reduced from 214 +/- 40/124 +/- 23 mm Hg to 145 +/- 23/88 +/- 9 mm Hg (P less than 0.001). In 11 of the 16 patients (69%) the values decreased to less than 160/95 mm Hg. These results suggest that, in complex forms of renovascular hypertension, antihypertensive treatment may be a potent therapeutic alternative if surgery and/or transluminal dilatation can not be performed or seem to have too high a risk.

Adult↗

[Unusual ophthalmic findings in a case of Niemann-Pick disease (author's transl)].

Case report on a woman patient who, although not Jewish, is suffering from Niemann-Pick disease. At the time of publication she is 55 years old, although this disease usually proves lethal in early childhood. Related atypical ocular changes were diagnosed, such as tortuosity of the retinal vessels and a conjunctival affection, which was demonstrated histologically.

Age Factors↗

[Diagnostic significance of lactate concentration in CSF in patients with meningitis (author's transl)].

White-cell count and differential blood count, total protein, lactate dehydrogenase activity (E.C. 1.1.1.27) and lactate concentration were determined in 496 CSF samples, obtained by lumbar puncture. Lactate was measured with a new enzymatic test. Reference values were determined for lactate and lactate dehydrogenase (90% limits: 1.2-2.1 mmol/l and 6-26 U/l, respectively). Lactate content proved to be best in the differential diagnosis between acute bacterial and abacterial meningitis: concentrations of 3.5 mmol/ml and above were found exclusively in bacterial meningitis. As for other diseases, markedly increased lactate concentrations were measured only in patients with brain tumour or cerebrovascular disease (up to 9.3 mmol/l). Determination of lactate concentration alone would have led to a misdiagnosis of acute bacterial meningitis in 3% of cases. If the CSF contains 3.5 mmol/l lactate or more and the leucocyte cell count is above 800/microliter, brain tumour or cerebrovascular disease can be practically excluded and the diagnosis of bacterial meningitis made with a high degree of reliability.

Adolescent↗

[Thorotrast kidney as a precancerous condition].

9 cases of "thorotrast kidney" after retrograde pyelography with reflux are presented. In 6 patients carcinoma of the renal pelvis developed 47--31 years after thorotrast pyelography. Because of this high rate of carcinoma induction, thorotrast kidney must be classified as a precancerous condition with high-rate tumor manifestation. Thorotrast kidney is diagnosed on X-ray by very opaque linear densities following the calices and pyelon. Early ureteronephrectomy is the treatment of choice in unilateral thorotrast kidneys. If uretero-nephrectomy is not possible, the patient should be followed up regularly with urinary cytologic examinations for early detection of malignancy.

Aged↗

Virus infections in renal transplant recipients.

534 serum samples from 73 renal transplant recipients, 41 haemodialysis patients, and 99 blood and organ donors were examined serologically for antibodies against Cytomegalo, H. simplex (types 1 and 2), Varicella-zoster, Epstein-Barr, Adeno, Influenza, Parainfluenza, Respiratory syncytial, Measles, Picorna- and human Polyoma- Viruses. Serum specimens were stored in the lyophilized state until examined thus enabling a simultaneous testing of all samples belonging to one patient. All antigens, complement, and control antisera were prepared, lyophilized, and standardized in this laboratory. This has enabled the use of single batches of any preparation throughout the study. Serologic results with antigens of the Herpesvirus group (CMV, HSV and VZV) compared favourably with previous results showing that infections with these agents, especially with CMV, can frequently be encountered among transplant recipients. Our results have indicated a moderately increased incidence of infections with some Herpesviruses in haemodialysis patients as well. Infections with VZV, for instance, were as frequently demonstrated in these patients, as in transplant patients although the former received no immunosuppressive therapy. Serologic results with non-Herpesvirus antigens indicated an increased incidence of infections with Polyomavirus, Myxoviruses (Influenza, Parainfluenza and RS) and Picornaviruses among transplant recipients. The incidence of acute infections with RS virus among adults was unusually high and there is no evidence so far to indicate such a high frequency of RS infections in any other group of adults. We were unable to demonstrate acute infections with non-Herpesviruses among haemodialysis patients, even though most of the patients were followed over a period of more than 2 years. Virus isolation attempts were performed with samples of urines and biopsy or autopsy samples. 23 out of 28 cytopathic agents recovered from urines, throat-swabs and/or from organs of transplant recipients were identified as CMV. Two HSV type 1, 1 HSV type 2, and 2 Coxsackie B type 3 viruses were also isolated. No viruses were isolated from a series of 31 kidneys randomly selected among autopsy cases.

Antibodies, Viral↗