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Biomedical subjects

A Seubert

Publications and source records attributed to A Seubert.

At least 37 records · Page 2Linked to original sources
PubMed1989

Studies on uroporphyrinogen decarboxylase of etiolated Euglena gracilis Z.

1. A 423-fold purified fraction of uroporphyrinogen decarboxylase (EC 4.1.1.37) showing a specific activity of 770 units/mg protein has been employed in order to study some properties in etiolated Euglena gracilis Z. 2. Uroporphyrinogen decarboxylase has a relative molecular mass of 54,000, an optimum pH of 7.2 and exhibits Michaelis-Menten kinetics, employing both uroporphyrinogen I and uroporphyrinogen III as substrates. 3. Anaerobic conditions seem not to be necessary for uroporphyrinogen decarboxylase activity. Neither EDTA nor cysteine affected enzyme activity, whereas dithiothreitol produced a remarkable activation of coproporphyrinogen formation. 4. Kinetic data employing both substrates showed an accumulation of porphyrinogen (i.e. hexa- and hepta-porphyrin) containing six or seven COOH groups, depending on the uroporphyrinogen concentration used. 5. An unusual elution profile of the intermediates on Sephacryl S-200 was found.

Animals↗
PubMed1986

Quincke's edema in a dialysis patient after administration of acrylic bone cement: possible role of ethylene oxide allergy.

A 33-year-old female dialysis patient suffered from osteomyelitis and luxation of the dens axis with cervical myelopathy. In the past she had had three attacks of anaphylaxis after treatment with dialyzers that had been sterilized with ethylene oxide. IgE-type antibodies directed against human serum albumin-ethylene oxide complexes could be demonstrated in the patient's serum by radioallergosorbent techniques. Immediately after an operation in which acrylic bone cement (Palacos-R) sterilized with ethylene oxide was implanted for stabilization of the cervical spine, the patient developed massive edema of the larynx, pharynx, and tongue, suggesting Quincke's edema. It is concluded that ethylene oxide present in acrylic bone cement may induce acute allergic reactions in sensitized patients. Dialysis patients may be at special risk, since the incidence of ethylene oxide allergy in this patient population is about 10%.

Adult↗
PubMed1986

Elimination of porphyrins and their precursors in rats pretreated with hexabromobenzene.

The elimination times of porphyrins and their precursors and of hexabromobenzene (HBB) itself were studied in female rats given 15 mg HBB by stomach tube every other day for 4 months. The concentrations of HBB in the blood, liver and adipose tissue were in the ratio 1:1.5:25, 24 hr after the last dose. Two weeks after the end of treatment, HBB was no longer detectable in the tissues. In animals given a single oral dose of 16.6 mg HBB/kg body weight, HBB was no longer detectable in adipose tissue 12 days after dosing. The half-life of HBB in adipose tissue was about 2.5 days in the animals given HBB for 4 months, and at the end of the treatment the concentrations of porphyrin in the liver, urine and faeces were increased to about 1000, 600-700 and 60-70 times the control values. The amounts of delta-aminolaevulinic acid and porphobilinogen in the urine of treated animals were 6-7 times those in controls. After the end of HBB treatment, it took almost 1.5 yr for delta-aminolaevulinic acid and porphobilinogen excretion to return to normal. Nearly 2 yr were needed for complete elimination of the accumulated liver porphyrins.

Adipose Tissue↗
PubMed1985

[Hypersensitivity phenomena in dialysis patients. Incidence of eosinophilia, raised IgE and ethyleneoxide-induced antibodies].

The hypersensitivity parameters eosinophil count, serum IgE and IgE-type antibodies to ethylene oxide-albumin conjugates (ETO-antibodies), were determined in 182 dialysis patients. Eosinophilia was seen in 21.7% of patients, IgE elevation in 21.4% and ETO-antibodies in 12.4%. A pathological change in at least one of the measured parameters was present in 33.1%. The appearance of ETO-antibodies was frequently associated with severe clinical symptoms, especially asthma and anaphylactic shock. Sensitisation is apparently common in dialysis patients. Since ETO-antibodies are often associated with severe clinical symptoms, their presence should be sought in those dialysis patients showing incompatibility reactions or asthma.

Adult↗
PubMed1985

A porphyria cutanea tarda-like distribution pattern of porphyrins in plasma, hemodialysate, hemofiltrate, and urine of patients on chronic hemodialysis.

The porphyrin investigations of plasma, dialysate, hemofiltrate, and urine in 50 chronic renal patients without bullae undergoing hemodialysis imply that a hyperporphyria exists. All 50 dialysis patients without blisters had significantly elevated plasma porphyrins with a mean of 27.4 micrograms/liter (SD: 10.0). Normal values were established in 51 nonporphyric ambulatory patients with normal renal function. The mean plasma porphyrin content in this group was 10.6 micrograms/liter (SD: 1.7). Porphyrin values in dialysates of 41 patients with chronic renal failure ranged from 2.6-6.3 micrograms/liter (mean, 3.9 micrograms/liter) and were much lower than the porphyrin content in hemofiltrates of 9 patients which ranged from 10-27 micrograms/liter with a mean of 20 micrograms/liter. In addition, plasma, hemofiltrate, and urine of 5 dialysis patients with blisters and porphyria cutanea tarda (PCT) were investigated. The plasma values were extremely elevated and exceeded those of PCT patients with normal renal function. Whether the dermatologic manifestations of chronic hemodialysis can be interpreted as a "forme fruste" of PCT should be subjected to further investigations.

Blood↗
PubMed1984

[Penetration of benzoyl peroxide in the skin].

Benzoyl peroxide preparations have proven to be effective agents in the treatment of acne. In comparison to the numerous clinical communications, very few reports exist concerning the pharmacokinetics of benzoyl peroxide. The benzoyl peroxide content of abraded horny layers and its metabolite benzoic acid were investigated by high-pressure liquid chromatography after application (1-2 min) of emulsion containing benzoyl peroxide. It was found that benzoyl peroxide penetrates the stratum corneum very quickly where it is rapidly degraded to benzoic acid. No benzoyl peroxide depot in the stratum corneum could be demonstrated.

Adolescent↗