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Biomedical subjects

J F Merlen

Publications and source records attributed to J F Merlen.

At least 19 recordsLinked to original sources
PubMed1989

[The value of studying the ocular conjunctiva in case-finding in prediabetic states].

Capillaroscopy, the only method available for the study of the microcirculation, without modifying its hydraulics, often provides a wealth of information in certain systemic diseases in which the microcirculatory involvement precedes clinical manifestations and of course, macrovascular complications. The prospective study of a healthy population is particularly demonstrative and the authors proposed scores on which diabetic microangiopathy could be suspected. The latter was confirmed by detailed laboratory investigations on one hand, and by the course of the disease on the other. For this reason, any subject at risk of diabetes should undergo at least one annual capillaroscopic examination of the ocular conjunctiva or if not, of the peri-ungual region. Furthermore, the study of microvessels in subjects with controlled and treated disease showed a regression of the anomalies which depended on proper control of diabetes, and this particularly nontraumatic test procedure which can be repeated and provides a wealth of information, can give a good reflection of proper therapeutic control, especially if it is performed by a trained and experienced investigator.

Capillaries↗
PubMed1987

[Flushes, blushing or hot flushes].

Apart from physiological flushes represented by emotional or prudish blushing, post-prandial flushes and menopausal hot flushes, various pathologic flushes exist of various etiologies: endocrine, dysmetabolic, histaminic and iatrogenic. Their pathogenicity is based mainly on local metabolites secretion provoking vasodilatation of the intermediary microcirculation rather than of the terminal microcirculation. Treatment is a function of etiology and therefore of the patient's history and results of clinical examination, functional exploration and standard biologic tests.

Blood Vessels↗
PubMed1986

[Microvascular disorders of adipose tissue].

The microcirculation of adipose tissue is poorly understood either because of the absence of histological documents or because they fail to explain pathological conditions. However, disturbances of blood flow and parietal lesions of the microvessels are the basis for these disorders. Although we speak of disturbances of the vascular control mechanisms, these mechanisms are poorly understood and although we speak of arteriovenous short-circuits, the existence of these lesions has not been proven. In fact, classically, the circulation in the dermis and hypodermis is assured by a meshwork of arterioles, venules and capillaries, but biopsies of lateral and anterior regions of the thigh have demonstrated "block devices" in the walls of small arteries and arterioles which are able to regulate the rate of blood flow towards the capillary bed. Following contraction of these devices, the vascular lumen dilates, ensuring free circulation and when they relax, the lumen closes, resulting in decreased or no blood flow. These smooth muscle devices within the arterial wall resemble small cushions in the small arteries and more or less pedunculated polyps in the arterioles, either simple or fissured in the form of an elephant's trunk with a safety valve effect, arranged either in a single column or in two columns face to face. This provides evidence for the particularly disturbed vasculo-tissue inter-relations observed in venous insufficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1986

[Chilblains].

Chilblain is a frostbite, it belongs to the vascular acrosyndromes by the mere fact of symmetrical lesions and to the dystrophic group by its organic obstructive and thrombotic microangiopathy, especially of venules. Chilblain is conditional on a dysesthesia for cold, diagnosis is easy if in the know, prognosis as usual good and treatment must be more preventive than curative.

Chilblains↗
PubMed1985

[Juvenile distal cerebral ischemia: value of pulp biopsy].

Juvenile distal cerebral ischemia has been attributed to small artery atherosclerosis (Arnold, Benoit, Merlen, Dobbelaere, Delandsheer, 1979), based on clinicopathologic findings in one male patient and results of big toe pulp biopsy in three other cases. Pathological findings were obstruction of small artery lumens by hypertrophic endothelium and loose fibrocellular bands, their origin being the result possibly of partial intimalization of media by elastic neogenesis. Appearances were similar to those described by Dahl in human cerebral atherosclerosis in 1976, and approached those of the initial stages of experimental atheroma (Ross, Glomset, 1976). Arterial exiguity was also present in the 4 cases. Results of biologic, metabolic, inflammatory and immunologic examinations were negative. The present study concerns 4 additional cases of juvenile distal encephalic ischemia. One case in a female patient not on oral contraceptives confirmed the hypothesis of intimalization of media of arterioles of big toe pulp. Elastic neogenesis was present in the tunica media in areas where there was a change of direction of myocytes, and was apparent at a distance from the internal elastic layer. The latter was fragmented, sometimes doubles and of variable color. In another case, a woman taking oral contraceptives, there was almost total obstruction of the pulp arteriolar lumens with a very thin tunica media. Elastic neogenesis encircled two very narrow lumens in the center of the vessel and there were also elastic changes common to both.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Microvascular consequences of low distal blood perfusion rates].

It is classical, in obstructive arterial disease, to be most concerned with the truncal arteries, although nutrition and exchanges occur at the level of the terminal vessels. The most important events occur in the muscles and in the skin, at the extremity of the limb and one wonders whether "ischaemic disease" could perhaps be summarized as the result of low perfusion rates. The laws of hydraulics are unusual in this situation, the microcirculation is autonomous and autoregulated. The architectonics are also unusual: the distribution into asymmetrical parallel networks explains the heterogeneity of the distribution in which stasis, conglutination and red cell rigidity, interstitial flooding and the rheological consequences play a major though unequal role in the skin and the muscle. The problems of the haematocrit, viscosity, surface tension or interface and the electrostatic potentials are more important at this level and they determine the therapeutic decisions.

Arterial Occlusive Diseases↗
PubMed1985

[The nail in vascular pathology].

The nail is part of the ungual unit; it is affected indirectly and late in vascular disease. The authors recall the anatomy and the blood supply of the ungual unit and describe the alterations in terms of the level of the lesion. They describe the changes seen in systemic diseases such as the collagen disease, in vascular disease, venous, arterial and lymphatic disease and in vascular acrosyndromes. These alterations are often a result of several diseases, but may, nevertheless, help orient the diagnosis.

Collagen Diseases↗
PubMed1985

[Evolution of vasomotor tone in chronic obstructive arteriopathy of the lower limbs].

Progressive degradation in the appearance of digital plethysmogram tracings occurs during acute episodes of occlusive arteriopathies, and is of importance for establishing the diagnosis and the choice of therapy. The distal microvasculotissular score is of major interest during the stages defined by R. Fontaine in 1966. Changes are in fact those of rheologic factors in the terminal network. It is logical to incriminate variations in "tone" and of vasomotor response, the final relay being at the site distal to the circulatory units and their endothelial receptors. The problem should be envisaged at each stage in the course of the disease. Vasoplasticity is a function of the severity of the arteriopathy.

Arterial Occlusive Diseases↗
PubMed1979

[Successive encephalic ischemic accidents in a young patient: Buerger's disease, buergerian syndrome, or juvenile atheroma? A report in clinical, angiographic, and anatomical findings in one case, compared to three other ones, in which a biopsy of the pulp of the toes was also performed (author's transl)].

A man of 19 years of age was found to have a diffuse livedo, a quadruple asphyxic acrosyndrome, and dementia. Angiography confirmed the presence of distal ischemia with multiple circulatory blocks and a reduced distal network. The patient died at the age of 25 years and histopathological examinations of the vessels demonstrated obstructive atheromatous lesions in the medium sized and small arteries of the brain and viscera. By comparing these findings with those observed in three other cases, in which biopsy of the pulp of the toe was also performed, the hypothesis can be advanced that these juvenile encephalic ischemic accidents are caused by atheroma, which can be detected, at an early stage, by studying the distal arteries in the finger or toe pulp.

Adult↗