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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↗
PubMed1983

[Paradoxical aspects of acrocyanosis and its pathogenesis].

First described by Crocq (1896) the clinical pattern of acrocyanosis is well known and its diagnosis is easy but acrocyanosis is a nosological frame with multiple aspects and a constitutional basis of microvasculotissular dysregulation. Acrocyanosis is made of capillarovenular hypotonia and stasis with a large and permanent opening of arteriovenous glomic anastomosis (J.F. Merlen, 1952).

Capillaries↗
PubMed1983

[Necrotic angiodermatitis].

Necrotic angiodermatitis, as defined and described by the School of Lyon and especially by D. Colomb, stays at the confines of dermatology and angiology. Its diagnosis is easy in front of such "cutaneous gangrene in superficial plates". In fact it is a microangiohistopathy, it appears like an infarction of the skin, due to atherosclerosis and so to senescence, it means a low flow of perfusion and perhaps relates to immunology.

Aged↗
PubMed1983

[Full popliteal fossa].

Many reasons of clinical discussions about a filling of the popliteal fossa arise from this special anatomical area which is encumbered, so often requested by the activity of joints and muscles and so, since the embryological development. Although rare, perhaps because unrecognised, ischemic disorders, venous signs, swollen legs, permanent or intermittent full fossa . . . are the more frequent clinical aspects. The main patterns are arterial, rarely venous and more rarely arteriovenous aneurysms, adventitial cystic disease, lipoma, synovial or sebaceous cyst . . . malignant tumours, exostosis . . . Serious examination, functional techniques of which Doppler, angiographies . . . So, quite a lot of diagnostic discussions, even during surgical interventions.

Adult↗
PubMed1983

[Acute symmetric polygangrene of the extremities].

The authors stress the importance, in acute symmetric polygangrene of the extremities, of systemic disease accompanied by decreased perfusion with its physicochemical consequences on parietal structures and the liquid contents of vessels and tissues developing rapidly in the extremities. In the first chapter, they recall the various aetiologies proposed in the literature. They then describe 3 personal case studies which they have chosen for their extreme age range and their varying aetiology. They present the various pathogenic factors which can occur either in isolation or in combination: parietal factors, abnormalities of the various elements of the blood, plasma factors, all of which are responsible for rheological disturbances which, when combined with decreased perfusion, lead to the development of gangrene. Finally, they present their ideas about treatment which sould be a function of the aetiology and the stage of the disease at the time of diagnosis.

Acute Disease↗
PubMed1982

[Impedance plethysmography. Comparison of sensibility and specificity in recent deep venous thromboses of the lower limbs (author's transl)].

Although phlebocavography remains the ideal technique of diagnosis and reference, impedance plethysmography is a simple non-invasive technique which records variations in impedance of a limb segment through which a H.F. current is injected and with distal venous occlusion. Variations in impedance go hand in hand with variations in volume. It is thereby possible to demonstrate any obstacle to venous flow, either of an obstructive type if there is thrombosis of the major proximal collecting vessels, or of a restrictive type if there is thrombosis in the leg. The technical conditions of the examination and measurement are here fundamental and hence the value of a specially designed apparatus and multi-input abacuses in order to determine indices of emptying, filling and filling rate with simultaneous examination of both limbs. The method is selective for the diagnosis of recent deep venous thrombosis: 83% correlation between impedance and phlebography, 16% false positive and 1% false negative, reliability at the level of the thigh in 98% of cases, lesser reliability in the calf though the score can be improved and touch 94% by comparison of the two legs (Franco). Wuydin has reported a specificity of 85% and a sensitivity of 96%. This reliable, specific, objective, atraumatic, inexpensive and easily repeatable method may be used to give an overall quantification of a proximal obstructive thrombosis and define the existence of a thrombosis in the calf.

Diagnosis, Differential↗