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Biomedical subjects

G Albrecht

Publications and source records attributed to G Albrecht.

At least 73 records · Page 4Linked to original sources
PubMed1988

Influence of ion-pair-formation on the pharmacokinetic properties of drugs. Part 3: Influence of hexylsalicylic acid on the pharmacokinetics of pholedrine.

Based on previous in vitro studies it could be shown that ion-pair-formation with the lipophilic hexylsalicylic acid (1) influences the pharmacokinetics of the hydrophilic drug pholedrine (2) which is ionized in all physiological media. After oral combination with 1 an increase of the AUC of 2 could be observed. This finding is due both to the increase of the absorption of 2 and to the decrease of the elimination of 2. After i.v. application the high biotransformation rate of 2 prevents an influence of 1.

Administration, Oral↗
PubMed1988

Influence of ion-pair-formation on the pharmacokinetic properties of drugs. Part 4: Influence of hexylsalicylic acid on the pharmacokinetics of bretylium.

Based on in vitro results it was found that the pharmacokinetic parameters of the hydrophilic drug bretylium (2) can be influenced by an ion-pair-formation with the lipophilic hexylsalicyclic acid (1). After simultaneous i.v. application of 1 and 2 on rabbits a significant increase of the AUC of 2 was observed. Under these conditions a marked increase of the AUC and the MRT of 1 was also obtained, since the blood levels of 2 are high enough for such an influence. A combined rectal application of 1 and 2 causes an increase of the AUC of 2.

Administration, Oral↗
PubMed1987

Collagen at interfaces. II: Competitive adsorption of collagen against albumin and fibrinogen.

Adsorption of chemically radiolabeled [14C] collagen from binary mixtures with albumin or fibrinogen was studied on the solution/air and solution/polyethylene interfaces and revealed the preferential adsorption of albumin. This phenomenon is confirmed by the data of surface tension measurements of single protein, collagen-albumin, and collagen-fibrinogen solutions. Desorption experiments clearly show that more irreversibly adsorbed collagen was found on polyethylene surfaces when adsorption was performed from collagen-fibrinogen than from collagen-albumin solutions. The combined adsorption-desorption and the surface tension data show that competitive adsorption of collagen at the hydrophobic surfaces is strongly influenced by the surface tension properties of the proteins in solution.

Adsorption↗
PubMed1987

The effect of prehepatic insulin administration on alanine flux rates in diabetic dogs.

The in vivo flux rates of glucose (6-3H-glucose) and of alanine (U-14C-alanine) were measured in insulin-dependent chronically diabetic dogs which were infused with insulin employing a bedside-type artificial B cell and either the peripheral or the portal venous route. In comparison with non-diabetic control animals the diabetic dogs had near-normal patterns of glucose metabolism and pancreatic glucagon regardless of the route of insulin administration. They also showed reduced basal portal but moderately elevated peripheral insulin levels on peripheral and near-normal peripheral values on portal insulin infusion. Both concentration and production rates of alanine were reduced on peripheral (0.142 +/- 0.016 mmol/l, 4.73 +/- 0.49 mumol.kg-1.min-1, p less than 0.05) but normal on portal insulin (0.206 +/- 0.030 mmol/l, 6.33 +/- 0.63 mumol.kg-1.min-1). The alanine clearance was slightly elevated or normal in the diabetic dogs, and the glucose production from alanine showed a strongly delayed response to an exogenous glucose load on either route of insulin administration. It is concluded that the peripheral hyperinsulinism during posthepatic insulin administration stimulates glucose utilisation to a normal extent, but inhibits the provision of amino groups in resting muscle. Alanine synthesis is thereby reduced, and the carbon moieties are shunted from glucose into circulating lactate. Long-term studies are needed to elucidate the role of the liver under these conditions.

Alanine↗
PubMed1987

36 months continuous subcutaneous insulin infusion (CSII) in insulin dependent diabetes (IDDM)--influence on early stages of retinopathy, nephropathy and neuropathy--psychological analysis.

UNLABELLED: In extremely unstable (brittle) IDDM patients (n = 11) the metabolic effect of long-term (36 months) CSII proved to be superior to conventional insulin treatment (CIT) (statistical twins, n = 11): HbA1 = 8.6 +/- 0.3 versus 10.4 +/- 0.4, MBG = 5.6 +/- 0.3 versus 8.5 +/- 0.8, M (80)- value = 23.6 +/- 0.6 versus 56.7 +/- 10.2, GCI) = 37.3 +/- 15.6 versus 132 +/- 24.2. In addition, in CSII patients the metabolic control was significantly better than intensified conventional insulin treatment (ICT) before. Retinal morphology improved under CSII in 1 eye, did not change in 10 eyes and deteriorated in 11 eyes. Under CIT retinal findings improved in none, did not change in 16 and deteriorated in 16 eyes. Deteriorations under CSII appeared more frequently during the first than during the second and third year of treatment and seemed to be a consequence of too strict metabolic control and/or too fast decrease of the glycemia at the beginning of CSII. During 36 months of CSII no deterioration but in one case normalization of microproteinuria was observed. Under CIT three cases changed from normal into microproteinuria. Reduced motor nerve conduction velocity (MCV) and/or sensory nerve conduction velocity (SCV) could be normalized in most cases under CSII, but respiratory heart arrhythmia (RHA) at rest could not. Most patients--if highly motivated before starting CSII--remained positively motivated for long-term pump therapy. IN CONCLUSION: Our experiences over three years demonstrate a positive effect of CSII on the metabolism as well as on the course of early stages of microangiopathy and neuropathy. A longer period of observations will be necessary to evaluate this, conclusively.

Adult↗
PubMed1987

Monolayer studies on poly(isobutylcyanoacrylate)-ampicillin association.

Surface pressure-area isotherms (pi-A) of poly(isobutylcyanoacrylate) monolayers with or without glucose and dextran as polymerization adjuvants used in the preparation of nanoparticles have been derived from measurements made at the air-water interface with the subphase pH at 2.7, 5.5 or 8.8. The isotherms were characteristic of the expanded type of polymer monolayer curves, yielding unusually low limiting area values compared with those of other known poly(acrylate) derivatives. This behaviour may be explained by the folding of polar moieties of the polymer groups in the water subphase. Ampicillin incorporated during preparation of nanoparticles had a negligible effect on the general behaviour of adjuvant-free monolayers, but a significant one on the adjuvant-loaded polymer monolayer system which showed an increase in surface area throughout the compression cycle, as compared with the surface area of the adjuvant-free polymer system although the collapse pressure was practically the same at 67 mN m-1.

Ampicillin↗
PubMed1987

Identical genomic footprints of the adenovirus EIIa promoter are detected before and after EIa induction.

Genomic DNase I footprinting was used to compare specific protein binding to the adenovirus type 5 early, EIa-inducible, EIIa promoter. Identical protection patterns of the promoter region were observed whether EIIa transcription was undetectable or fully induced. These results suggest that EIa-mediated transcriptional induction does not increase binding of limiting transcription factors to the promoter but rather that transactivation results from the proper interactions between factors already bound to their cognate sequences.

Adenoviridae↗
PubMed1987

[Skin reaction to dithranol and its modification by the addition of tar (LCD)].

In spite of 70 years' continuous use of dithranol for the topical treatment of psoriasis, there are few reports of contact hypersensitivity reactions to this compound. A male patient with psoriasis had an adverse skin reaction to the traditional topical dithranol treatment; patch tests revealed contact dermatitis in response to 0.02% dithranol in petrolatum, which was characterized by marked erythema and severe bullous reaction to 0.1% dithranol in acetone. A control group of ten volunteers tested under similar conditions did not react with marked erythema until a concentration of 0.1% dithranol in petrolatum was applied. When liquid tar (5% liquor carbonis detergens, LCD) was added to the patch test solutions concentrations that were clearly one or two steps higher were needed before the erythematous skin reaction was induced. Since minimal erythema generally appears in patch tests with greater than or equal to 0.05% dithranol in petrolatum, we believe that in the patient reported here contact hypersensitivity to dithranol was present. The development of large perilesional erythematous areas with accompanying edema during topical dithranol treatment supports this suggestion. It seems that the addition of liquid tar elevates the reaction threshold to dithranol in hypersensitive patients with psoriasis.

Anthralin↗
PubMed1987

Prevalence and incidence trends of non-insulin-dependent diabetes mellitus (NIDDM) in the population of the GDR.

Trends of prevalence and incidence rates of non-insulin-dependent diabetes mellitus (non-insulin-treated diabetes mellitus) were assessed in the population of the GDR based upon the National Diabetes Register and the Official Statistical Year Book as sources for the calculations. Within the 25-year follow-up period 1960-1984 the prevalence rose from 4.39%; to 31.95%; the incidence rate from 1.04%; to 3.57%. Age-dependence of the specific rates is characterized by their continuous rise above the age of 30 years reaching the peak prevalence of 146.6%; in 75- to 80-year-olds, that of 14.1%, for the incidence in people aged 70 to 75 years. A significant male preponderance was confirmed between the ages of 30 and 50 years, a significant overwhelming of female NIDDM in the age groups 60 to 90 years. Based on demonstrated correlations between the changes of living standard parameters and the epidemiological trend of NIDDM the conclusion is drawn that overnutrition and reduced muscular activity mainly account for the rise of diabetes morbidity in the population of the GDR.

Cross-Sectional Studies↗
PubMed1986

[Condylomata acuminata. Recent aspects of clinical signs, pathogenesis and therapy].

Condylomata acuminata and its rare variants (bowenoid papulosis and giant condylomata) are caused by human papilloma viruses (HPV), especially by HPV type 6. In spite of radical surgery, a 68-year-old woman suffering from giant condylomata acuminata of Buschke and Löwenstein on her vulva developed several local recurrences. Assuming that patients with recurring condylomata might have a defect in their cellular immunity, we examined subsets of circulating T-lymphocytes in the peripheral blood of ten patients by means of monoclonal antibodies. T-helper cells were decreased in number; the ratio of T-helper and T-suppressor cells was within the lower normal range. As to the common treatment with podophyllin, several precautions have to be considered in order to avoid local or systemic damage (i.e., irritations, contact dermatitis, vomiting, neuropathies, or fever). The use of interferon seems to be a new alternative. A 21-year-old patient, whose condylomata had been surgically removed six times but had always recurred, was treated with interferon recomb A (rA-INF). This patient has now been treated for eight weeks with 18 mill. I. E. every other day, and he did not develop any recent condylomata.

Aged↗
PubMed1986

[The Berlin Model. A multicenter study of prednicarbate in various vehicles].

We report on the results of an openly conducted multicenter study concerning efficacy and tolerance of a new prednisolone derivative free from halogenic groups (prednicarbate 0.25%, Dermatop) prepared as a) emulsifiable greasy ointment without water, b) w/o emulsion (ointment), and c) o/w emulsion (cream). These preparations were therapeutically applied in eczema (allergic, seborrheic, microbic), psoriasis, and atopic dermatitis. The study was carried out in close team work between a clinic and 37 practicing dermatologists and included 383 patients. After 3 weeks therapy, 4% of the patients did not reveal any satisfying results; 16% showed medium outcome with some persisting symptoms; in 80% of the patients, we observed good to very good therapeutic results.

Administration, Topical↗
PubMed1986

[Histologic variation in the width of trichoepitheliomas].

Our histopathological study deals with the evaluation of 232 solitary or multiple trichoepitheliomas, which have been examined by means of hematoxylin-eosin staining. The characteristic features of these benign adnexal tumors have been described with special emphasis on changes of the surrounding stroma. We found a great variation with regard to the size and number of cysts, the maturity of the epithelium and surrounding stroma, as well as the amount of affected stroma. In some cases, a clear separation between trichoepithelioma and keratinizing basal cell epithelioma was not possible.

Connective Tissue↗
PubMed1985

Alterations in alanine metabolism in diabetic dogs during short-term treatment with an artificial B cell.

The flux rates of plasma glucose and alanine were studied isotopically (6-3H-glucose and U-14C-alanine simultaneously) in resting chronically diabetic dogs during short-term treatment with an artificial B cell where the insulin was infused into a peripheral vein. Despite perfect blood glucose control and normal glucose flux rates, the concentration and rates of appearance and disappearance of alanine were significantly elevated in the diabetic animals before, during and after an exogenous glucose load. The incorporation of the carbon moiety of alanine into circulating glucose was also increased, but diminished to a near-normal extent when exogenous glucose was given. The plasma clearance rates for alanine in the diabetic dogs were normal throughout the study. It is concluded that normal blood glucose control in diabetes does not necessarily mean normalization of the entire metabolic network. On the basis of peripheral hyperinsulinaemia alanine formation from glucose and branched chain amino acids is elevated in muscle. This may explain increased flux of alanine despite normal blood glucose control.

Alanine↗
PubMed1985

Daily glucose and insulin rhythms in diabetic dogs on the artificial beta cell.

The circadian periods of plasma glucose, insulin and alpha-amino nitrogen (alpha-AN) were studied in fed and fasting normal and diabetic dogs which were fed either beef or beef supplemented with carbohydrates (CH). The diabetics were either withdrawn from insulin supply or treated with an artificial beta cell (ABC) or infused a constant insulin dose (CI).--There was a significant daily glucose rhythm in normal fasting animals and in fasting diabetics on CI or on insulin withdrawal. In the fed controls, the phase of the rhythms depends on carbohydrate content of food. In CH-free fed controls the insulin maxima were related to alpha-AN but in CH-fed controls they were related to glycemia. Due to the mechanism of ABC-provided insulin dosage, the phases of glucose and of insulin oscillations were correlated in all diabetics on ABC. Thus even if the mean glucose level is normalized by ABC the intrinsic phase relations remain altered.--It is concluded that the daily glucose periodicity is based on endogenous rhythms in glucose production and utilization and is essentially independent of current insulin provision. But it is governed by the meals as main "Zeitgebers" and modified by the actual insulin supply.

Amines↗