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H H Neumayer

Publications and source records attributed to H H Neumayer.

At least 163 records · Page 9Linked to original sources
PubMed1987

Effect of dialyzer membranes on in vitro generation of eicosanoids.

Eicosanoids are potent substances released from blood cells after contact with foreign materials. Eicosanoid generation, in addition to complement fragment formation, may be a valuable indicator of the biocompatibility of dialyzer membranes. In the present in vitro study, eicosanoid generation induced by several different flat dialyzer membranes [polyacrylonitrile (PAN), cuprammonium cellulose (CC), and polycarbonate (PC)] was evaluated and compared using blood from non-uremic healthy volunteers. Generation of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) was greatest with PC followed by PAN and CC. The formation of C3a des arg with PAN was less than with either CC or PC. Our results suggest that dialyzer membranes affect complement activation and eicosanoid generation differently; biocompatibility as expressed by a low level of complement fragment formation does not necessarily translate into biocompatibility when considering eicosanoid generation.

Acrylic Resins↗
PubMed1986

[Protective effect of the calcium antagonist diltiazem on acute kidney failure following kidney transplantation. The results of a prospective randomized study].

UNLABELLED: In a prospective randomised study the effect of the calcium antagonist diltiazem on primary transplant failure following cadaver kidney transplantation was studied. The transplants were perfused with a solution containing 20 mg/l diltiazem, the graft recipient received diltiazem as a bolus injection of 0.28 mg/kg pre-operatively, followed by a continuous infusion of 0.0022 mg/kg X min for 48 hours. Thereafter diltiazem was applied orally (twice 60 mg/d). Glomerular filtration rate and renal blood flow were measured by single-shot techniques (inulin, PAH). For immunosuppression ciclosporin A and low-dose methylprednisolone were given. Nine patients (41%) in the control group (n = 22) but only two (10%) in the diltiazem group (n = 20) developed primary transplant failure (P less than 0.05). Glomerular filtration rate in transplants with primary function was significantly higher in the diltiazem group (day 4: 29 +/- 0.8 vs. 20 +/- 0.8; day 7: 39 +/- 1.4 vs. 24.9 +/- 0.7 ml/min, P less than 0.05) although ciclosporin blood levels were significantly higher in this group (week 1: 1150 vs. 728 ng/ml, P less than 0.01). The rate of rejection episodes was significantly higher in controls than in patients on diltiazem (0.5 +/- 0.05 vs. 0.1 +/- 0.02 rejection episodes per patient in the first postoperative month, P less than 0.05). CONCLUSION: Diltiazem has a protective effect against primary transplant failure following cadaver kidney transplantation. Furthermore, it might reduce the nephrotoxicity of ciclosporin A.

Acute Kidney Injury↗
PubMed1986

[Prevalence of antibodies against LAV/HTLV-III in patients with terminal renal insufficiency treated with hemodialysis and following renal transplantation].

Sera of 1046 patients undergoing haemodialysis for terminal renal failure or after renal transplantation were tested with the ELISA screening test for anti-LAV/HTLV-III and, if positive, the Western blot and ELAVIA tests. Four patients (0,38%) had "true" antibodies against LAV/HTLV-III, confirmed by the Western blot and ELAVIA tests. These patients had definite signs of cellular immune defects. They had received transplants from drug addict donors. Such kidneys should therefore no longer be used for transplantation. In addition, 29 patients (2.8%) had "false-positive" antibodies against LAV/HTLV-III in the ELISA test, unconfirmed in the Western blot and ELAVIA tests. The "false-positive" result was presumably due to cross-reaction with HLA antibodies. Sera of dialysis and transplantation patients who had received many blood transfusions should therefore be especially carefully tested before a diagnosis of infection with LAV/HTLV-III is made.

Antibodies, Viral↗
PubMed1986

Acute interstitial nephritis and non-oliguric renal failure after cefaclor treatment.

A case of acute interstitial nephritis (AIN) developing after cefaclor treatment is reported. Diagnosis was proofed by kidney biopsy and lymphocyte transformation test. The clinical course of the patient with non-oliguric renal failure was favourable. Four weeks after discontinuation of cefaclor treatment the renal function was completely restored and remained stable over the ten-month follow-up period. It is concluded that cefaclor can cause hyperallergic AIN and acute renal failure.

Acute Kidney Injury↗
PubMed1986

The influence of long-term infusion of the calcium antagonist diltiazem on postischemic acute renal failure in conscious dogs.

The influence of long-term infusion of the calcium-entry blocker diltiazem on postischemic acute renal failure was investigated in conscious dogs monitored by implanted instruments. In 18 uninephrectomized beagle dogs on a salt-rich diet, an electromagnetic flow probe and an inflatable plastic cuff were placed around the renal artery. Acute renal failure was induced by inflating the cuff for 180 min in the conscious animal. Group A (n = 5, control) received an intraaortic injection of 0.9% NaCl (5 ml/day) from the 3rd day before until the 7th day after ischemia and group B (n = 6, posttreatment) an intra-aortic injection of diltiazem (5 micrograms X min-1 X kg-1) beginning at the end of ischemia until the 7th day. Group C (n = 7, pre- and posttreatment) received diltiazem from the 3rd day before until the 7th day after ischemia. In group A, renal blood flow dropped from 149 +/- 16 (preischemic) to 129 +/- 29 ml X min-1 on the 1st day after ischemia. In contrast, renal blood flow increased on the 1st postischemic day in both treatment groups by 29 +/- 15% (group B, P 0.05) and 14 +/- 13% (group C). In the following days, there was no significant difference in renal blood flow between groups A, B and C. In group B, the reduction of the glomerular filtration rate was similar to that in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1985

Beneficial effects of long-term prostaglandin E2 infusion on the course of postischemic acute renal failure. Long-term studies in chronically instrumented conscious dogs.

The effect of a continuous intra-aortal infusion of prostaglandin E2 (PGE2) (0.03 microgram . min-1 . kg-1) on the course of postischemic renal failure (180 min cessation of blood flow by inflation of a pneumatic cuff) has been investigated in 11 conscious sodium-replete dogs. The glomerular filtration rate (51Cr-EDTA: endogenous creatinine clearance) was less decreased in the PGE2 group (group B, n = 6) than in the control group (group A, n = 5; 13 ml . min-1 vs. 22 ml . min-1; p less than 0.05). Renal blood flow (electromagnetic flow probe) was markedly lower in the control group (82 ml . min-1) than in the PGE2 group (130 ml . min-1; p less than 0.05), even exceeding baseline levels in the latter group. Accordingly, the excessive rise in renal vascular resistance in the control group (+277%) was abolished in the PGE2 group (-20%) (p less than 0.05). Nitrogen retention was also markedly improved. Plasma renin activity, which was markedly raised initially (25.8 ng angiotensin I . ml-1 . h-1) was not significantly further increased during the subsequent 7 days. Urinary excretion of PGE2 was diminished in the control group and elevated following PGE2 infusion. It is suggested that the beneficial effects of PGE2 are mediated by preservation of renal perfusion. Additional effects of prostanoids on the ultrafiltration coefficient (KF) and cytoprotection by reduction of intracellular calcium accumulation must also be taken into consideration.

Acute Kidney Injury↗
PubMed1984

Prostaglandin E2 promotes hypotension on low-sodium hemodialysis.

The influence of low-sodium dialysate (126 mmol/l) on plasma levels of prostaglandin E2 (PGE2) and PGF2 alpha, plasma renin activity (PRA) and arterial blood pressure was investigated in 16 patients on maintenance hemodialysis. PGE2 rose more than tenfold and there was a significant increase in PGF2 alpha and PRA. Mean arterial pressure dropped by 30 mm Hg causing discomfort in several patients. By contrast, conventional hemodialysis against 140 mmol/l of sodium was followed by less pronounced changes in plasma prostaglandins, and reduction of blood pressure was moderate (13 mm Hg). It is suggested that vasodilating prostaglandins may contribute to dialysis hypotension. Their origin may not be confined to the kidneys but rather extend to the lungs and circulating blood cells. The in vitro generation of prostaglandins was demonstrated when donor blood was circulated in an extracorporeal dialysis system.

Dinoprost↗
PubMed1983

Elimination kinetics of plasma exchange.

Interest in the therapeutic use of plasma exchange for various diseases is growing. The two different effects of plasma exchange are elimination and activation. The kinetics are linear for elimination by plasma exchange, but not for activation. Plasma exchange is performed intermittently and can be described by intermittent kinetics. According to intermittent kinetics, plasma exchange removes 50% to 75% of a substance in plasma within 1-2 h, corresponding to an elimination half-life of 30-40 min. Hybrid kinetics, a mixture of actually intermittent but theoretically continuous elimination by plasma exchange, can however also be applied. Hybrid kinetics are more convenient and more reliable than intermittent kinetics. This is because hybrid kinetics are based solely on the concentrations before each plasma exchange; hybrid kinetics also reflect removal from the entire body and not just from the plasma compartment. According to hybrid kinetics, the amount of a substance in the body removed within 3-4 days is 50% of the difference between the initial and the final plasma concentration, depending on the intensity of plasma exchange. The intensity may well contribute at least in part to the beneficial effect of plasma exchange in various diseases.

Antibodies↗
PubMed1982

Influence of prostaglandins A1, E1, E2, and F2 alpha on renal blood flow and plasma renin activity. Investigations in chronically instrumented conscious dogs.

The effects of different prostaglandins (PG) on serial determination of renal blood flow (RBF), mean arterial blood pressure (MABP), renal vascular resistance (RVR) and renin release were investigated in the conscious, chronically instrumented dog. 2 months after right-sided nephrectomy, female beagle dogs (n = 6) were implanted with an electromagnetic flow probe and an inflatable pneumatic cuff around the left renal artery, and a catheter was inserted into the aorta above the renal artery. In repeated experiments, different prostaglandins (PGA1, E1, E2 and F2 alpha) were infused above the renal artery at increasing doses (infusion time 15 min, doses 0.03--1.0 micrograms min-1 kg-1). Lower and medium doses induced an increase of RBF, which returned to or were slightly below control levels with higher doses. PGA1 appeared to be the most potent vasodilator with a significant hypotensive activity and the greatest augmentation of RBF. Simultaneously, renin release was most pronounced by PGA1.

Animals↗