Search PubMed⌕ Search

Biomedical subjects

H Gras

Publications and source records attributed to H Gras.

At least 37 records · Page 2Linked to original sources
PubMed1981

Local light stimulation of isolated chromatophores of the sea urchin Centrostephanus longispinus.

The dark-reaction (pigment aggregation) of isolated, light-sensitive pigment cells of the sea urchin Centrostephanus longispinus was monitored using IR-microscopy. It differs in time course and mode of pigment displacement from the inverse process of pigment dispersion in white light. Partial illumination of darkness respectively causes locally different and appropriate pigment movements in the individual cell regions. Spot-illumination of a cell process of an otherwise darkened chromatophore leads to local pigment dispersion (from thd dark-adapted state) or aggregation (from the light-adapted state) exactly to the point of stimulation, while the pigment cell shows normal dark-reaction in all other regions. The results indicate that the pigment granules do not bear the receptor pigment, rather it may be expected in the whole cell membrane. The observation of contrary translocations in different regions of the cell support the concept of a local mechanism of granule movement regulated in a very precise manner.

Animals↗
PubMed1980

Ultrastructural observations on changes in cell shape in chromatophores of the sea urchin Centrostephanus longispinus.

Alterations in cell shape of the light-sensitive chromatophores of the sea urchin Centrostephanus longispinus were studied by scanning- and transmission electron microscopy. Transition of the aggregated to the dispersed state is accompanied by incorporation of vesicles into the membrane of the pigment cell. During disperson a system of microtubules originating from centriole-like structures is established throughout the stellate cell. Within restricted areas of the cell, cytoplasmic differentiation and condensation is found. The possible functional significance of the findings is briefly discussed.

Animals↗
PubMed1979

[Hemodynamic effects of hydralazine in the cardiac insufficiency of non-obstructive myocardiopathy].

The haemodynamic effects of a single dose of between 0.15 and 0.25 mg/kg hydralazine were studied during cardiac catheterisation of 9 patients with primary congestive cardiomyopathy and heart failure. The systemic arterial resistances decreased (--1 370 +/- 400 dynes/s.cm-5/m2, p less than 0.05); the reduction of pulmonary arterial resistances was less marked (--420 +/- 400 dynes/s.cm-5/m2, p less than 0.05). Intraaortic pressure was reduced (--16 +/- 12 mmHg, p less than 0.02) as was average pulmonary arterial (--4.2 +/- 4,2 mmHg, p less than 0.05) and left ventricular end diastolic pressures (--4.2 +/- 3.0 mmHg, p less than 0,02). Systolic index increased in all cases (+13 +/- 5 ml/syst/m2, p less than 0.001). Heart rate was unchanged. This was due to the improvement of left ventricular function by the reduced impedence. These results confirm the place of hydralazine in the treatment of certain forms of heart failure.

Adult↗
PubMed1978

[Clinicopathological study of the causes of mortality during the acute phase of myocardial infarction (author's transl)].

Clinical and autopsy study of 100 cases of patients dying during the first 3 weeks of hospitalisation for myocardial infarction revealed the following causes of death: cardiac failure in 59 cases (including 40 of cardiogenic shock), rupture of the heart in 29 cases (24 of rupture of the ventricular wall, 4 of the septum and 1 of a mitral papillary muscle). 4 ventricular arrhythmias and 6 haemorrhagic or embolic complications. In 2 cases, the cause of death could not be accurately determined. In cardiogenic shock, death usually occurred early. It was later in cases of refractory left ventricular failure. Conduction disturbances were much commoner in cases of myocardial infarction complicated by fatal cardiac failure (57.6%) than in the presence of any other complication (17.1%) (p less than 0.001). The responsible infarction was often extensive and recurrent. Rupture of the heart invariably occurred during the first three days of an infarction often initial (p less than 0.001), anterior (apart from septal rupture) and small in size (p less than 0.01). Other complications play only a secondary role in mortality at the present time, in particular arrhythmias, the gravity of which has greatly decreased since the reduction of delays before hospitalisation and improvements in anti-arrhythmic therapy.

Acute Disease↗
PubMed1977

[Rupture of an infective aneurysm of the sub-renal abdominal aorta into the inferior vena cava. One case (author's transl)].

An aorto-caval fistula developed in a 62-year-old woman secondary to the rupture of an infective aneurysm of the aortic bifurcation. Treatment in relation to local and, above all, general infection is discussed, emphasising the value of epiplooplasty and prolonged appropriate antibiotic therapy. However, adequate follow-up is essential in order to be able to affirm cure, recurrence of the infectious process always being possible, even late.

Anti-Bacterial Agents↗
PubMed1977

Light-induced alterations in cell shape and pigment displacement in chromatophores of the sea urchin Centrostephanus longispinus.

Alteration in cell shape of the ligh-sensitive chromatophores of Centrostephanus longispinus are described. Upon illumination a centrifugal pigment movement starts within extremely thin filopodia which radiate from the cell body. With continued pigment migration the cellular processes increase in length and diameter and give the cell an irregular stellate appearance. Pigment movement within the cellular processes is discontinuous in space and time and may occur independently in single filopodia. The motion of single granules shows characteristic features of a saltatory movement.

Animals↗