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Biomedical subjects

M Mayr

Publications and source records attributed to M Mayr.

16 recordsLinked to original sources
PubMed1989

Different anisotropies of movement direction in upper and lower layers of the cat's area 18 and their implications for global optic flow processing.

Cells in Area 18 of awake and behaving cats were tested for directional preference with a large visual noise pattern. Upper and lower layer cells were found to exhibit different anisotropies for movement direction, offset by 90 degrees. These findings could reflect different functions for the global mapping and processing of optic flow field in upper and lower layers.

Animals↗
PubMed1987

Myocardial metabolism of free fatty acids. Studies with 14C-labeled substrates in humans.

Free fatty acids are considered to be the major energy source for the myocardium. To investigate the metabolic fate of this substrate in humans, 24 subjects underwent coronary sinus and arterial catheterization. 13 subjects were healthy volunteers and 11 subjects had symptoms of ischemic heart disease. [1-14C]oleate or [1-14C]palmitate bound to albumin was infused at a constant rate of 25 microCi/h. Oxidation was determined by measuring the 14CO2 production. The data demonstrated that a high percentage (84 +/- 17%) of the palmitate and oleate extracted by the myocardium underwent rapid oxidation. A highly significant correlation was present between the arterial level and the amount oxidized (r = 0.82, P less than 0.001 for palmitate; r = 0.77, P less than 0.001 for oleate). The isotope extraction ratio was greater than the chemical extraction ratio. This difference of 6 +/- 2 nmol/ml of blood in the young normal subjects was significantly less than the 12 +/- 4 nmol/ml observed in the ischemic heart disease patients (P less than 0.001).

Adolescent↗
PubMed1985

Differences in direction specificity of receptive fields in upper and lower layers of the cat's prestriate area 18.

Direction specificity was measured for neurons in area 18 (A18) in penetrations approximately perpendicular to the layers in awake cats. A majority of lower layer cells (below 1.0 mm) preferred stimuli moving at rather orthogonal directions with respect to the preferred directions of the neurons in the upper layers (0-1.0 mm). The results suggest more functional autonomy of the corresponding cortical layers.

Animals↗
PubMed1984

Single cell activity in area 18 of the cat's visual cortex during optokinetic nystagmus.

Single cell activity was recorded in area 18 during optokinetic nystagmus (OKN) in awake cats. The search coil technique was used to record the horizontal and vertical eye movements. Cells showing direction specific responses to a moving large area random dot pattern (70%) were tested with different velocities in the preferred and in the null-direction. Their response characteristics can be classified according to the two phases of the OKN. 41% responded specifically to the retinal slip velocity, having their response optimum at different values between 2 and 100 degrees/s. Additionally, in 60% of all tested cells the resetting saccades of the OKN were correlated with brief activity bursts of 39 ms latency on the average. These results are discussed in terms of two concepts: the classic concept of a corollary discharge from the oculomotor system and the concept of a gating function of the reticular system on thalamic and cortical transmission.

Animals↗
PubMed1978

[Specific glucocorticoid receptor activity in the lungs and concentration of corticosteroids in the plasma of newborn rabbits during the first hours of life (author's transl)].

Nine pure-bred albino New Zealand white rabbits were delivered on the 30th day of gestation (term 31 days) by Caesarean section. The concentration of dexamethasone binding receptors in the cytosol and nucleus of the lungs as well as the total plasma corticosteroid levels were measured in the newborns before the first breath, after 30 min, 1, 2, 4, 6 and 24 h after birth. The level of plasma corticosteroids increased after birth while the concentration of the receptors in the cytosol and nucleus decreased but was still present after 24 h as well as in the lungs of adult animals. A temporary increase in the concentration of the nuclear receptors after 1 and 2 h is explained by the translocation and binding of the abundantly produced steroid-receptor-complex to the nucleus. The stress of hypo- and hyperthermia on the newborns showed variable behaviour with respect to receptor activity. However, the relationship between the corticosteroid levels in the plasma and the concentrations of the receptors in the cytosol and the nucleus of the lungs was similar as in fetuses kept under "physiological" conditions. It may be concluded from these results that in the rabbit the specific glucocorticoid receptor activity in the lungs decreases after birth but is present throughout life.

Adrenal Cortex Hormones↗
PubMed1970

[Rib osteomas].

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

[Clinical and radiologic comparison of "idiopathic" and "neurogenic" pes cavus].

41 patients with 66 cavus feet were reviewed clinically and radiologically according to the parameters of Dennemann at an average age of 41.3 years. The etiology was a so-called "idiopathic pes cavus" in 51 per cent of the cases, in the others, a neurological basic disease (15 per cent condition after poliomyelitis, 3 per cent meningocele, 6 per cent Friedreich's ataxia, 10.5 per cent other neurological disorders) or condition after congenital club foot or trauma. Exact neurological and electrodiagnostic examination of the cavus feet primarily staged as idiopathic revealed sensory or motor loss in 74 per cent of the cases. A comparison of the "idiopathic cavus feet" with the cavus feet in neurological basic diseases with respect to the radiological parameters showed no significant differences concerning progression and osteoarthritis. Conservative and surgical measures were carried out with roughly the same success. In 36 cases (55 per cent), however, complaints on the part of the ankle joint and the talo-calcaneonavicular joint and the metatarsal head were noted.

Adolescent↗