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Biomedical subjects

M Schmidt

Publications and source records attributed to M Schmidt.

1,095 records · Page 61Linked to original sources
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Effects of SK&F 82526 and SK&F 83742 on the renal vascular dopamine receptor.

The renal vascular effects of benzazepine derivatives were studied on the isolated perfused rat kidney in the presence of phenoxybenzamine and sotalol after contraction of the vascular bed with prostaglandin F2 alpha. SK&F 82526 was a very potent dopaminomimetic drug (ED50 = 7.6 +/- 0.8 X 10(-9) M) on the renal vascular dopamine receptor. It displayed partial agonist activity (similar to SK&F 38393) and was devoid of alpha-adrenomimetic effects. SK&F 83742 was a potent dopaminolytic drug. It antagonized dopamine-induced relaxation of the renal vascular bed in a competitive way, with an apparent pA2 of 7.47 +/- 0.23.

Animals↗
PubMedDate not supplied

[Interaction between non-steroidal anti-inflammatory agents and lithium salts].

Since the first observation in 1978, it has been clearly established that the non-steroidal anti-inflammatory drugs (NSAIDs) interfere with the pharmacokinetics of lithium: by reducing urinary clearance of the metal, they can raise the plasma lithium level and thus lead to intoxication. Among the NSAIDs available in France, this interaction has been reported with phenylbutazone (Butazolidine, Carudol), diclofenac (Voltarène), indomethacin (Indocid) and its antalgic derivative clomethacin (Dupéran), ketoprofen (Profenid), mefenamic acid (Ponstyl), niflumic acid (Nifluril) and piroxicam (Feldène). This interaction does not occur with aspirin; this exception suggests that the inhibition of prostaglandins synthesis is not the mechanism responsible for the decrease in the urinary elimination of lithium linked with an increase in its tubular reabsorption. In practice, in view of the growing diffusion of NSAIDs, it is necessary to inform all patients under lithium treatment of the risk of interaction resulting from their use.

Animals↗
PubMedDate not supplied

[Theophylline and urinary elimination of lithium in the anesthetized dog].

The effect of theophylline (intrarenal perfusion of 1.2 then of 2.4 mg/kg for two successive 15 minute periods) on urinary lithium elimination was studied in 6 pentobarbital anaesthetized dogs perfused with intravenous lithium chloride. Lithium and inulin clearance and the urinary elimination of sodium, potassium and phosphate were studied. Theophylline increases lithium clearance, glomerular filtration and salidiuresis. This salidiuretic effect partly linked to the inhibition of the proximal reabsorption of sodium attested by the rise in phosphate elimination contrasts with the absence of modifications in the fractional tubular reabsorption of lithium. Under our experimental conditions the increased lithium clearance seems linked to the increased glomerular filtration.

Anesthesia↗
PubMedDate not supplied

[Validation of Guttman scales of vigor and readiness to make social contacts in the aged].

Two Guttman-scales for the assessment of functional health and sociability of aged persons were examined in several different samples concerning their scalability, dimensionality, and validity. They proved well suited for a relatively broad use. Contrary to other measures of ADL-functioning, our functional health scale discriminates the upper levels of functional competence. In regard to expert-ratings as well as to measures of actual behavior, both scales proved to be valid. The functional health scale correlates significantly with the Barthel Index but shows a better sensibility for changes of functional competence during a half-year period.

Activities of Daily Living↗
PubMedDate not supplied

[The mechanism of the natriuretic action of dopamine in the anesthetized dogs (author's transl)].

1. The natriuretic effect of increasing doses of dopamine (1.5 to 15 x 10(-8) moles/kg/min intrarenally) was compared in dogs (pentobarbital anesthetized) who were either water restricted or overhydrated. 2. The dopaminergic response to doses larger than 1.5 x 10(-8) moles/kg/min (3 micrograms) was hidden either by important alpha-adrenergic effects or by renal reaction to the modifications in systemic haemodynamics. 3. Renal blood flow was increased by a dose of 1.5 x 10(-8) moles/kg/min of dopamine. At the same dose, natriuresis was increased only in hydrated dogs. Glomerular filtration rate only increased in water restricted animals. 4. The natriuretic effect of dopamine depended on the catecholamine induced variations of renal haemodynamic. 5. In water restricted animals, the absence of natriuretic effect of dopamine goes in hand with an absence of variation in filtration fraction. 6. In hydrated animals, the dopamine-induced natriuretic effect, in the absence of increased glomerular filtration, is tied to a decreased proximal tubular reabsorption of sodium probably secondary to the haemodynamic effects of this catecholamine.

Anesthesia↗
PubMedDate not supplied

Instability of side-chain protecting groups during MALDI-TOF mass spectrometry of peptide fragments.

Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS), a well-suited method for the characterization of peptides and proteins, was used for analysis of protected peptide fragments. It is shown that acidic matrices, e.g. 2,5-dihydroxybenzoic acid, frequently used in MALDI-TOF MS of peptides, causes partial cleavage of acid-labile side-chain protecting groups. Because this effect is strongly related to the matrix used, the observed deprotection can be avoided by choosing an appropriate matrix such as 2,4,6-trihydroxyacetophenone or 2-amino-5-nitropyridine. The advantage of neutral matrix compounds for MALDI-TOF analysis of protected peptides is clearly demonstrated, confirming the potential of MALDI-TOF mass spectrometry.

Amino Acid Sequence↗
PubMedDate not supplied

Collection of oviduct fluid in heifers.

The present experiments were undertaken in order to develop an alternative way of collecting oviduct fluid from heifers (n = 13). Under general anesthesia and through a midline incision, catheters were anchored in the ampullar region of the oviduct with ligatures of silk or steel and the uterotubal junction ligated. Subsequently, they were guided through the uterine wall into the lumen of one uterine horn and then transversed caudally through the cervix and vagina until they finally passed the vulva-vestibulum and could be attached to cryotubes taped to the tail. Fluid was collected daily over an average of 60 days for all animals (range 6-183). When only steel suture was used the average collection time was 99 days. The volume reached maximal values on the day of heat. In conclusion, the present experiment showed that it is possible to use alternative ways for bovine oviduct catheterization which permitted sampling without any noticable discomfort for the animals. The sampling period increased considerably when steel replaced nylon in the fixation of the catheters in the ampullar part of the oviduct.

Animals↗
PubMedDate not supplied

[Sialidosis and galactosialidosis as the cause of non-immunologic hydrops fetalis].

Two cases of non-immunological hydrops fetalis (NIHF) presenting with massive ascites are reported; in both patients an oligosaccharid-pattern in the urine typical for sialidosis resp. galactosialidosis was found. The cerebral sonography of both patients showed streaky echo enhancement in the region of the thalamostriatal vessels, which was interpreted as calcification of the vessels. The courses of the patients were characterised by recurrent infections, hepatosplenomegaly and myoclonus. Relevant literature reports on a large variability in the clinical appearance of oligosaccharidoses. The diagnosis of sialidosis is confirmed in cultured fibroblasts by the deficiency of alpha-N-acetylneuraminidase and, in case of galactosialidosis by the additional lack of beta-galactosidase. The precise diagnosis in NIHF is of increasing interest for prenatal diagnostic as well as for neonatological management.

Brain↗