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Biomedical subjects

R Gross

Publications and source records attributed to R Gross.

659 records · Page 37Linked to original sources
PubMedDate not supplied

Calcium channel modulation: ability to inhibit or promote calcium influx resides in the same dihydropyridine molecule.

BAY K 8644, a dihydropyridine of the nifedipine type, was shown to increase coronary resistance and to enhance myocardial contractility (Schramm et al., Nature 1983;303:535-7), in contrast to the well-known vasodilating and negative inotropic effects of the "classical" calcium channel blockers. In the isolated perfused guinea pig heart at high concentrations (greater than 3 microM), however, the coronary constricting and positive inotropic effects of BAY K 8644 progressively reverse until the drug has a negative inotropic effect and decreases coronary resistance, thus mimicking the effects of the "classical" calcium antagonists. On the other hand, in the same experimental model, calcium antagonists like nifedipine, nitrendipine, and nicardipine are shown to exert a small but definite positive inotropic effect at low concentrations, indicating a calcium agonistic action at those concentrations. To explain the pharmacological effects of BAY K 8644 and the calcium channel blockers of the dihydropyridine type, a model is proposed that suggests the existence of two dihydropyridine binding sites per channel. According to this model, it depends on the chemical structure of the respective dihydropyridine whether, after occupation of the first site, which increases the calcium influx through the channel, the occupation of the second site is unimpaired, turning the channel to one with low calcium permeability; or whether occupation of the second site is hindered, leaving the channel in the high conductance state.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMedDate not supplied

The total alkaloid and anagyrine contents of some bitter and sweet selections of lupin species used as food.

The total alkaloid and anagyrine contents of bitter and sweet Lupinus luteus, Lupinus angustifolius, Lupinus albus, Lupinus mutabilis, Lupinus polyphyllus, and Lupinus perennis were analyzed by gas chromatography (GC) and mass spectrometry. No anagyrine was detected in any of the samples. The GC peak in some of the samples which corresponded to anagyrine in retention of time seems to be identical to 17-oxolupanine. The alkaloid content of samples ranged from 3.17 to 0.003 percent.

Alkaloids↗
PubMedDate not supplied

[Prevention of postsurgical thromboembolism with small doses of heparin].

The study includes 390 patients of different age, operated for various conditions during the last quarter of 1975, and systematically treated post operatively with heparin (the cases in which heparin was contraindicated were not included). None of the patients developed signs of thromboembolism after the operation. The drawbacks of the method are virtually inexistent as compared to the gravity of postoperative thrombolic complications. A further study included 1708 operated patients of whom 223 (13.0%) received the heparin treatment and 1485 (87.0%) did not. There was no thrombolic-embolic complication in the former lot and 12 cases (0.8%) in the latter. Three of 15 patients (20%) in whom the postoperative heparin treatment was interrupted immediately or very soon, developed thromboembolism. The method is efficient provided it is applied after the operation up to complete mobilization of the patient. The method is readily applicable, there is no risk and haemostasis is insured.

Adolescent↗
PubMedDate not supplied

[Percutaneous oximetry assessment of oxygen pressure in feet with spastic hemiparesis following stroke].

In the period 1988-1993 at the Geriatrics Department percutaneous oximetric determinations of oxygen pressure were done in 40 patients with spastic hemiparesis after stroke. The obtained results indicated a lower pressure of oxygen in the foot of the paretic extremity as compared with contralateral extremity. This suggests a relationship between the degree of oxygen supply to the tissues and the side of hemiparesis following stroke.

Aged↗
PubMedDate not supplied

Painful spondylolisthesis in a two-year-old child.

Spondylolisthesis is considered one of the common causes of back pain in children. There are far fewer cases reported in children under the age of 4 years. However, all patients described were diagnosed by radiographic examination in a workup for other congenital or musculoskeletal abnormalities. This report describes a 2-year-old girl who presented with low back pain and was subsequently diagnosed with spondylolisthesis.

Child, Preschool↗