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Biomedical subjects

A Hofmann

Publications and source records attributed to A Hofmann.

At least 163 records · Page 9Linked to original sources
PubMed1978

Historical view on ergot alkaloids.

A short survey of the history of ergot, of the original and, for a long time, only source of ergot alkaloids, is given. Once a dreaded poison, ergot has changed its role over the centuries to become a rich treasure house of valuable pharmaceuticals. In the Middle Ages it was the cause of epidemics of ergotism, which cost tens of thousands of people their lives. Ergot was first mentioned by the German physician Lonitzer in 1582 as a remedy used by midwives for quickening childbirth. The isolation of pharmacologically useful alkaloids started in 1906 with the discovery of ergotoxine and its adrenolytic activity by Barger, Carr and Dale. In 1918, Stoll isolated ergotamine, the first chemically pure ergot alkaloid, which found widespread therapeutic use in obstetrics and internal medicine. In 1935 the specific oxytocic principle of ergot, ergonovine, was discovered simultaneously in four separate laboratories. Since then, worldwide investigations on ergot alkaloids resulted in the elucidation of their structures and total syntheses and preparation of valuable therapeutics such as Methergine, Hydergine, Dihydergot, and others.

Chemistry↗
PubMed1978

Anaesthetised normotensive rats for the detection of hypotensive activity of a beta-adrenoceptor antagonist and other antihypertensive agents.

A simple method for the detection of antihypertensive activity in anaesthetised (66 mg/kg i. v. alpha-chloralose and 20 mg/kg i. v. aprobarbital) normotensive rats is described. Dihydralazine (0.5 to 2 mg/kg i. v.) reduced blood pressure dose-dependently but did not provoke the anticipated tachycardia. Clonidine (1 to 8 microgram/kg i.a.), guanethidine (0.5 to 5 mg/kg i.a.) and alpha-methyldopa (2.5 to 10 mg/kg i.a.) reduced blood pressure dose-dependently; the effect of reserpine (0.1 to 1.0 mg/kg i.a) was, however, not dose-dependent. Although all four drugs reduced heart rate, only clonidine and guanethidine did so in a dose-dependent manner. Phentolamine (0.5 to 2 mg/kg i. v.) and propranolol (0.01 to 1 mg/kg i. v.) elicited dose-dependent falls in blood pressure. Whereas phentolamine increased heart-rate slightly, propranolol elicited a bradycardia. It is concluded that the chloralose-aprobarbital anaesthetised rat is a suitable and economical model for the screening of potential antihypertensive agents including beta-adrenoceptor antagonists. However, reflex trachycardia provoked by peripheral vasodilators may not be apparent.

Adrenergic beta-Antagonists↗
PubMed1976

Efficacy of gut lavage, hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication.

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents. Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1-2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1-2 ppm, the clearance values for hemoperfusion were some 5-7 times higher than those for hemodialysis. In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquats less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

Adult↗
PubMed1976

[Cytogenetic studies as a contribution to the diagnosis of juvenile preleukemia and leukemia recurrence].

Hematologic changes in panmyelopathia are characterized by a wide-spreading spectrum of symptoms and a rare specifity. Therefore cytological and cytochemical findings do not allow a significant prognosis for the malignant or benign development of panmyelopathia. Cytogenetic experiments showed only the Philadelphia chromosome being of diagnostic value. MEISNER and co-workers, who studied adults with panmyelopathia and proven myelocytic leukemia and 5 children with acute lymphocytic leukemia, found that significant and persistent spontaneous division in unstimulated 24 hr. peripheral blood cultures is an indication of a malignant state. The present work shows that in two of five children with panmyelopathia and with significant spontaneous division chronic myelocytic leukemia developed or was in the very initial state; a third child with spontaneous division is still under control. In contrast to literature only one of 14 children with ALL had significant spontaneous cell division. Therefore the method applied must be checked for its usefulness in ALL and especially for its usefulness in early recognition of a relapse.

Child↗
PubMed1976

Toxicological study on pramiverine (author's transl).

4,4-Diphenyl-N-isopropyl-cyclohexylamine-hydrochloride (pramiverine, Sistalgin) was investigated alone and in combination (1 + 1000) with N-methyl-N-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl)-aminomethanesulfonate (metamizole) in various species for acute toxicity after oral and intravenous administration, for local tolerance and subacute toxicity. In addition, long-term trials and reproduction toxicity studies were performed with pramiverine. Pramiverine was only slightly toxic and was well tolerated locally as an ampoule solution also in combination with metamizole. The acute trials of the two compounds in mice and rats like the subacute study in rats showed that the toxicity of metamizole was not increased by pramiverine. Rats tolerated in the long-term trial all pramiverine doses examined (0.5; 5.0; 50.0 mg/kg), while cholinolytic concomitant effects were observed in dogs under higher doses (5.0 and 20.0 mg/kg). Pramiverine did not have a foetotoxic and teratogenic effect in mice, rats and rabbits. In the perinatal and postnatal experiment in rats no effect on foetal development, viability and growth of the offspring as well as the course of labour and lactation ability of the dams was observed.

Administration, Oral↗
PubMed1975

On the question of extracorporeal hemodialysis in diquat intoxication.

Extracorporeal hemodialyses were carried out in a female patient with severe diquat intoxication. Diquat clearance was on average, 3.17 ml/min. Only 0.84 mg diquat could be eliminated from the blood serum by 11.5 hrs of dialysis. Hemodialysis is therefore not an efficient technique for removing amounts of diquat from the organism that are toxicologically relevant one day after ingestion.

Adult↗
PubMed1975

Affinity-labelling of the muscarinic receptor of the guinea-pig illeum.

1. The activities of some cholinergic compounds were investigated on the terminal ileum of the guinea-pig and their muscarinic potencies were found to be in the following order: acetylcholine (ACh) greater than diazoacetylcholine (DACh) greater than iodoacetylcholine (IACh) greater than azidoacetylcholine (AACh). 2. Protection experiments with atropine showed a decreased affinity of the four cholinergic compounds for the muscarinic receptor, demonstrating a direct interaction of the drugs and the receptor. 3. The maximal contractions (intrinsic activity) caused by DACh were greater than those casued by ACh, IACh and AACh. 4. Incubation of the ileum with ACh was followed by a reversible loss of its ability to contract (desensitization). The time course of recovery was similiar to that after incubation with AACh. 5. IACh caused a partial (50%), irreversible paralysis of the muscle. 6. The furaziridines seem to react partially irreversibly (30%), whereas paranitrophenyldiazonium fluoborate (p-NDP) caused a complete, irreversible blockade of the muscarinic receptor.

Acetylcholine↗