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Biomedical subjects

M Späth

Publications and source records attributed to M Späth.

At least 55 records · Page 3Linked to original sources
PubMed1979

Platelet aggregation evoked in vitro and in vivo by phosphatidic acids and lysoderivatives: identity with substances in aged serum (DAS).

In serum incubated at 36 degrees C for 18-24 hours a factor (DAS) develops which on intravenous injection into cats evokes platelet aggregation followed by an increase in pulmonary vascular resistance (PVR). This change in PVR is mediated via the platelets since it significantly correlates with the preinjection platelet count. There is evidence that phosphatidic acids (PA) and lysophosphatidic acids (LPA) are the active components of DAS. Investigations performed on platelet-rich plasma from man, cat, pig, dog, rabbit, guinea pig, and rat demonstrate that only human and feline platelets exposed to PA or to LPA are aggregated. Feline platelets are more sensitive to either compound than are the platelets from men; however, human platelets exhibit two exceptional properties, a) the sensitivity rapidly declines with time, b) pretreatment with subthreshold concentrations of LPA or PA induces a specific tachyphylaxis.

Adenosine Diphosphate↗
PubMed1978

Experimental studies on the intestinal uptake of organic and inorganic magnesium and potassium compounds given alone or simultaneously.

The peroral administration of magnesium and potassium compounds in effective doses (ED50) to rats yielded the following results: 1. Magnesium or potassium given as chlorides are significantly better absorbed than the corresponding aspartates. 2. In the presence of aspartate in higher concentrations the absorption of both magnesium and potassium is inhibited to a certain degree. 3. Increasing amounts of chloride cannot abolish the inhibitory effect of aspartate on potassium absorption, in contrast magnesium, which, in the presence of aspartate is better taken up when chloride is provided. 4. High concentrations of magnesium may perhaps impede the uptake of potassium to a small degree but not vice versa. 5. Magnesium losses from the body--induced by treatment with 9-alpha-fluorocortisol-acetate--can be effectively substituted by peroral administration of chloride-containing magnesium compounds over a reasonable time. The simultaneously occurring loss of potassium cannot be corrected correspondingly by potassium supplements.

Animals↗
PubMed1977

The effect of metacaine (MS-222) on the activity of the efferent and afferent nerves in the teleost lateral-line system.

1. Free-swimming fish (Tilapia leucosticta and Rutilus rutilus) were used to determine threshold concentrations required for general anesthesia with metacaine (MS-222). The criterion for anesthesia was reached at a concentration of 1:1500 (w/w) with both fish, although the symptoms were somewhat more pronounced in Rutilus. 2. Recordings of efferent spontaneous activity in the lateral-line nerve were used as a measure of the central effect of metacaine during administration in the respiratory stream, as compared with respiration of fresh water. The reduction of activity at the end of a 3-min exposure to the drug was 70%. 3. Maximum recovery (90% of the initial activity) was reached after 30 min application of fresh water. 4. The various efferent impulse types were differentially affected by the anesthetic. 5. Direct recordings from sound-sensitive neurons in the medulla confirm the strong central effect of metacaine. 6. Irrigation of the lateral-line system with anesthetic solution also produced a reduction in afferent spontaneous activity; there was a distinct peripheral effect even at the threshold concentration. 7. Reactions of trigeminal nerve fibers to mechanical stimulation of the skin were reduced after application of a metacaine solution to the skin. This finding confirms the local anesthetic effect of the drug. 8. The anesthetic solution at a given concentration had a greater effect on the CNS than on the peripheral receptors. 9. The implications of the results with respect to the risk of misjudging the depth of general anesthesia are discussed. 10. Because of the complexity of its anesthetic efficacy, it is recommended that metacaine not be used for neurophysiological investigations, but rather that the animals be immobilized by means of muscle relaxants.

Action Potentials↗
PubMed1976

Reactions of the goldfish (Carassius auratus auratus L.) to quantified mechanical and thermal stimuli.

Goldfish can differentiate between mechanical and thermal stimuli components in combined stimulations. Reactions to heated thermode (deltaT = + 3 degrees C) differ from those to isotherm thermode by up to 30%. Additional pretension (0.5 p) increases the reaction more than double; at simultaneously varied temperature (deltaT = + 3 degrees C and + 5 degrees C), there is a further increase in reaction of 25% and 35%. The significance for the organism of the two stimuli components is discussed.

Animals↗
PubMed1976

Magnesium concentrations in plasma and bone following enteral administration of Br-, Cl- and Mg++ in the form of different compounds and combinations.

In accordance with the results achieved in previous experiments the intestinal absorption of magnesium and its uptake into bone of rats were significantly improved when MgCl2 or mono-magnesium-mono-aspartate-hydrochloride (Mg asp. HCl) were used instead of mono-magnesium-di-l-aspartate (Mg asp.). Treatment with mono-magnesium-mono-aspartate-hydrobromide (Mg asp. HBr) resulted in remarkably elevated magnesium concentrations in plasma and bone. Since the animals were strongly sedated at the same time, we had to differentiate the influence of anesthesia from unspecific distress and specific actions of bromide and chloride, e.g. on intestinal uptake and/or renal excretion of Mg. Experiments in which the narcotic effect of bromide was reduced to moderate sedation by additional treatment with chloride would appear to suggest that both specific and unspecific mechanisms were involved. In additional experiments it was shown that the effects of Mg asp. plus KBr or Mg asp. plus KCl or CaCl2 were similar to those of the corresponding magnesium aspartate hydrohalogenides.

Administration, Oral↗
PubMed1975

[Pharmacology and pharmacokinetics of magnesium (author's transl)].

A dose-dependent fall in diastolic blood pressure, pulse rate, systolic pressure, inhibition of neuromuscular transmission and blockade of sympathetic ganglia could be demonstrated during infusion of magnesium in animal experiments. In sighting trials in two clinically healthy subjects, suggestions of a phasic course for plasma Mg were found, with a minimum in the morning. After administration of magnesium asparate hydrochloride in enteric coated capsules, the plasma Mg rose, depending on the dose, with a maximum at 3.7 hours. Raising the plasma Mg over 24 hours is possible with a total dose of 9 mg/kg Mg, divided into two or three doses daily. For reasons of absorption and better tolerance, division into three doses seems more advantageous.

Adult↗
PubMed1975

Improvement by chlorine of the intestinal absorption of inorganic and organic Mg compounds and of their protective effect against adrenergic cardiopathy.

Comparative studies on the therapeutic effects of MgSO4, MgCl2, Mg aspartate, and Mg aspartate hydrochloride were carried out in Sprague-Dawlwy rats. In general, the intestinal absorption of Mg and its uptake into bone were improved after oral or intraduodenal administration of the two compounds containing chlorine; however, in these animals, gain in body weight was reduced, especially after MgCl2. Treatment with 9-alpha-fluorocortisol plus epinephrine resulted in cardiac hypertrophy and necroses. All Mg compounds fed in amounts leading to marked hypermagnesemia prevented hypertrophy; as regards the incidence and severity of necroses, however, MgSO4 and Mg aspartate proved ineffective. Significant protective effects were observed only after MgCl2 and Mg aspartate hydrochloride, indicating the central pathogenic role of extracellular hypochloremic alkalosis in metabolic heart necroses.

Animals↗