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Biomedical subjects

G Blanc

Publications and source records attributed to G Blanc.

At least 73 records · Page 4Linked to original sources
PubMed1979

Blockade by benzodiazepines of the selective high increase in dopamine turnover induced by stress in mesocortical dopaminergic neurons of the rat.

The effects of electrical foot shock on the activity of the ascending dopaminergic neurons were estimated in the rat by measuring the changes in DOPAC and DA levels in discrete brain areas. DOPAC and DA levels were estimated with a radioenzymatic method in microdiscs of tissues punched out from serial frontal sections of the brain. A marked rise in the ratio of DOPAC/DA levels resulting from an increase of DOPAC and a decrease of DA levels was found in the cerebral frontal cortex at the end of a 20 min stress. The effect was less pronounced in stress of shorter duration from 3 to 10 min and was only related to a reduction of DA levels. Using the DOPAC/DA ratio as an index of the activity of the neurons, the mesocortical dopaminergic neurons were found to be selectively activated under stress since this ratio was increased in the frontal and cingular cortices but not in limbic structures such as the septum, the amygdala and the nucleus accumbens or in the striatum. Finally, pretreatment of the rats with diazepam (5 mg/kg i.p.) or chlordiazepoxide (10 mg/kg i.p.) prevented the increase in the DOPAC/DA ratio in the frontal cerebral cortex of rats submitted to the 20 min stress.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

Increased utilization of dopamine in the nucleus accumbens but not in the cerebral cortex after dorsal raphe lesion in the rat.

Dihydroxyphenylacetic acid (DOPAC) and dopamine (DA) levels were estimated in the frontal cortex, the nucleus accumbens and the striatum of the rat after electrolytical lesion of the dorsal raphe nucleus. The efficiency of this lesion was tested by measuring the decline in serotonin (5-HT) levels in the striatum. 5-HT levels were reduced by 90% when compared to those of sham-operated rats 11 days after the lesion. As revealed both by the increase in DOPAC levels and in the DOPAC/DA ratio, the rate of DA utilization was markedly increased in the nucleus accumbens, slightly enhanced in the striatum and in contrast remained unaffected in the frontal cerebral cortex 4 days after the lesion. Changes in DOPAC levels in the nucleus accumbens were also seen 11 and 30 days after the lesion but they were less pronounced than those observed at 4 days. These results suggest that neurons originating from the dorsal raphe and projecting to the ventro-tegmental area are regulating the activity of the meso-nucleus accumbens dopaminergic neurons but not that of the meso-cortical dopaminergic neurons.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

[Risks and median-term results of aortic valve replacement for calcifying aortic stenosis in 100 patients more than 70 years old].

100 patients with poorly tolerated calcific aortic stenosis underwent aortic valve replacement by the same surgical team (Starr-Edwards prosthesis: 52 cases, Bjäork prosthesis: 43 cases, Lillehei-Kaster prosthesis: 2 cases, and Hancock bioprosthesis: 3 cases) between July 1971 and April 1978. The hospital mortality was 17% and acute pulmonary oedema and cardiomegaly were poor preoperative prognostic factors. The late mortality was 14.5% with an average follow-up period of 25 months (range: 2 to 74 months). The survival rate expressed as an actuarial graph was 63.1 +/- 4% at 4 years. 90% of the patients operated move up at least one class in the New York Heart Association classification and 2/3 return to Stage I. The cardiothoracic ratio improved from 0.58 +/- 0.06 to 0.51 +/- 0.03 (p less than 0.02) and the Soko low-Lyon index from 40 +/- 13 to 25 +/- 6 (p less than 0.001). The main complication encountered at middle term was haemorrhage, observed in 17.5% patients. Comparison of the spontaneous outcome of the disease with the results of surgery favour surgical treatment of patients over 70 years old with poorly tolerated calcific aortic stenosis. The valve of choice should be the bioprosthesis when dependance on anticoagulant therapy and the associated risks of haemorrhage are taken into consideration.

Aged↗
PubMed1979

[Comparative study of the fate of a pancreatic stump treated by ligature or by pancreatico-jejunal anastomosis (author's transl)].

The authors studied in a series of 23 dogs divided up into two groups the fate of the pancreatic stump treated either by pancreatico-jejunostomy with a Y loop, or by a simple ligature. They note that although the mortality is slightly higher in the anastomoses, histological lesions are constant in both series and are fairly similar. This agrees with the findings in man by Goldsmith and justifies ligature of the remaining pancreatic stump after cephalic duodeno-pancreatectomy.

Animals↗
PubMed1978

Topographical distribution of dopaminergic innervation and dopaminergic receptors of the anterior cerebral cortex of the rat.

The quantitative topographical distribution of the dopaminergic innervation and the DA-sensitive adenylate cyclase were estimated in the anterior cerebral cortex of the rat. The high affinity uptake of [3H]DA and endogenous levels of DA were used as markers of the dopaminergic innervation. [3H]DA uptake, DA levels and DA-sensitive adenylate cyclase were estimated in microdiscs of tissues punched out from frozen serial frontal slices. The uptake of [3H]DA was measured on sucrose homogenates prepared from such microdiscs. The ventral part of the frontal cortex contained the highest DA concentration and DA-sensitive adenylate cyclase activity; the other structures rich in DA and in DA receptors were the cingular (close to the corpus callsoum) and the rhinal cortices. All of these cortical areas were rich in [3H]DA uptake sites. However, curiously, the dorsal part of the frontal cortex, which contained only moderate amounts of DA and of DA-sensitive adenylate cyclase, presented the highest number of [3H]DA uptake sites. Nevertheless, the uptake of [3H]DA in this region decreased by 60% after bilateral electrolytical lesions of the ventral tegmental area (A10 group). The parietal cortex was practically devoid of dopaminergic innervation and of DA-sensitive adenylate cyclase. The activity of the DA-sensitive adenylate cyclase in the frontal, cingular and rhinal cortices was 10-fold higher than that found in the striatum when compared to their respective DA levels.

Adenylyl Cyclases↗
PubMed1978

[Obstructive cardiomyopathy and associated coronary atherosclerosis. Review of the literature and report of 2 personal cases].

The association of idiopathic hypertrophic subaortic stenosis (IHSS) with significant coronary atherosclerosis is little known, only 43 cases being available in the literature, 2 of which are personal ones. But the incidence of this association has certainly been underestimated. It is especially found from the sixth decade onwards, and at least 20% of patients with IHSS in and above the age group have stenosing lesions of the coronary artery. It is almost impossible to establish the presence of associated coronary abnormalities from the clinical features of from electrocardiogram. It does however seem worthwhile looking for this condition in IHSS when there is refractory chest pain, especially to beta-blockers, particularly if the patient is aged over 50 and has risk factors for ischaemic heart disease. It is also good to find IHSS associated with known coronary artery disease by using simple non-invasive techniques such as phonomechanocardiography and especially echo-cardiography; it is important not to miss the myocardial lesion and to treat concurrently if there is likely to be an indication for dealing with the coronary arteries surgically. The beta-blockers are the treatment of choice for both conditions, together with anticoagulents. If they fail, myectomy or myotomy together with aorto-coronary bypass graft should be considered.

Cardiomyopathy, Hypertrophic↗
PubMed1977

[Traumatic rupture of the corpus cavernosum. Three cases (author's transl)].

"Fracture of the penis" by damage to the erectile structures is rare. This accident usually occurs when the erect penis is subjected to trauma, usually during intercourse. The diagnosis is easy in the presence of a haematoma spreading from the fraenulum to the scrotum, with sometimes an obvious breach in the albuginosa of one corpus cavernosum. In the three cases reported here, immediate surgery was possible in two. Early operation, with repair of the ruptured albuginosa, offers the best guarantee of cure without any disturbance in erection.

Adult↗