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Biomedical subjects

B Michel

Publications and source records attributed to B Michel.

At least 181 records · Page 10Linked to original sources
PubMed1978

Pemphigus antibody interaction with human epidermal cells in culture.

The mechanism of pemphigus acantholysis has been studied with an in vitro system. Freshly prepared human skin epidermal cells were incubated in F-10 medium which contained the immunoglobulin G fraction from either pemphigus serum or normal human serum. During 18-h incubation periods, the pemphigus antibody became bound to the surface of the epidermal cells, caused the destruction of 75% of the viable cells as compared to only 14% in the normal immunoglobulin G controls (trypan blue exclusion), prevented the accumulation of newly synthesized proteins by nearly 60% as determined by radioactive tracer studies, and caused a dramatic shift in distribution of the newly synthesized proteins from an insoluble cell-associated fraction to an extracellular soluble fraction. These effects on the accumulation and partitioning of newly synthesized proteins were antibody concentration-dependent. Kinetic studies showed that at a fixed pemphigus antibody concentration the inhibition of protein accumulation preceded solubilization by about 1 h, at which time rapid solubilization of up to 70% of the insoluble cellular material occurred. Several lines of evidence suggested that this phenomenon was caused by enzymatic activity. Epidermal extracts solubilized a prepared substrate of radioactivity labeled insoluble epidermal cell material. This activity was heat labile and pH dependent, with pH optima ranging from 4.5 to 6.5. Enzymes with pH optima between 6 and 6.5 were recovered in the culture medium after a 2-day incubation of pure, intact epidermis with the pemphigus antibody. We proposed the following hypothesis to account for pemphigus acantholysis. The pemphigus antibody reacts with the epidermal cell surface and produces such a severe disturbance that the integrity of the cell surface is lost. As a result of these primary perturbations, the cell is killed and during the process, responds by release or activiation of soluble hydrolytic enzymes. This autolytic process results in the characteristic acantholysis of pemphigus.

Acantholysis↗
PubMed1978

Epidermal acantholysis induced in vitro by pemphigus autoantibody. An ultrastructural study.

Suprabasilar acantholysis can be produced in organ culture of normal human skin in the presence of pemphigus IgG autoantibody. We have examined this in vitro system by electron microscopy. The earliest ultrastructural changes at 12 hours included widening of the intercellular spaces and disruption of the intercellular cement substance in the nondesmosomal areas. After 24 to 48 hours in culture, the tonofilaments retracted from the cell periphery, desmosomes were lost, and extensive cell surface digitation occurred. By 72 hours, isolated cells without noticeable desmosomes were seen in the suprabasilar areas, whereas basal cells, with intact hemidesmosomes, remained attached to the basal lamina. Control cultures which were grown in the presence of normal IgG or F-10 medium alone did not manifest these changes. The ultrastructural features support the conclusion that the acantholysis produced in this system is similar and probably identical to that of naturally occurring pemphigus.

Acantholysis↗
PubMed1977

Skin basement membrane immunofluorescence in rheumatoid arthritis: lack of diagnostic correlation.

Thirty-nine patients with rheumatoid arthritis were studied for the presence of skin basement membrane immunofluorescence. Punch biopsies from normal sun-exposed skin of the forearm were negative for basement membrane immunofluorescence in all cases, except one which was read as questionable. No correlation with serum antinuclear antibody or lupus erythematosus cells was observed. Skin immunofluorescence studies are helpful in differential diagnosis when patients with a clinical picture of rheumatoid arthritis present with serum antinuclear antibodies and lupus erythematosus cells. Positive basement membrane immunofluorescence is strong evidence of systemic lupus erythematosus.

Adolescent↗
PubMed1977

An organ culture model for the study of pemphigus acantholysis.

An in vitro model for the study of pemphigus acantholysis has been developed. The histological changes of pemphigus vulgaris were reproduced in vitro in organ culture by growing normal human skin in the presence of pemphigus vulgaris or pemphigus foliaceus sera. At 24 h a suprabasilar split was noted and at 72 h extensive suprabasilar acantholysis developed. Direct immunofluorescent tests demonstrated that pemphigus antibody became bound to the epidermal intercellular space antigen(s) during the first 6-12 h. As acantholysis increased the presence of tissue-fixed antibody decreased. The fixation of the pemphigus antibody to the skin prior to the development of acantholysis provides strong evidence for the pathogenetic role of this antibody in the production of acantholysis. The data suggest that complement is not required in this model for the production of the acantholytic changes of pemphigus since heating the serum for 30 min at 56 degrees C did not destroy the acantholytic activity and no complement (C3) could be detected by DIF of organ culture explants.

Acantholysis↗
PubMed1977

Factors influencing small bowel changes in dermatitis herpetiformis.

Factors influencing small bowel morphology in dermatitis herpetiformis (DH) were investigated by comparing patients with DH and normal small bowel biopsies to patients with DH and abnormal small bowel biopsies. The mean age of 18 patients with morphological changes in small bowel (38 years) was significantly lower (P less than 0-001) than the mean age of nine patients with normal bowel mucosa (60 years). HLA typing confirmed the high frequency of HLA-B8 in DH (64%) but HLA-B8 was unrelated to the presence or severity of small bowel lesions. Four patients had diarrhoea with progressive weight loss or abdominal cramps subsequently responsive to gluten withdrawal. In this subgroup serum levels of IgG and IgM were significantly lower than in patients with normal small bowel mucosa. Small bowel involvement appeared to be independent of the duration and severity of skin disease, and the deposition of immunoglobulin and complement (C3) in the dermal papillae of skin adjacent to skin lesions.

Adult↗
PubMed1977

Hodgkin's disease and mycosis fungoides in a married couple.

Hodgkin's disease and mycosis fungoides are malignancies in which there is abnormal T lymphocyte proliferation. The authors report the occurrence of Hodgkin's disease and mycosis fungoides in a husband and wife, respectively. This represents another instance of clustering of cases of T lymphocyte malignancies.

Adult↗
PubMed1977

Cicatricial pemphigoid of Brunsting-Perry. Immunofluorescent studies.

Six patients with a vesiculobullous eruption of the type described by Brunsting and Perry as benign pemphigoid were studied by direct and indirect immunofluorescence. All six showed linear deposits of IgG but not IgM or IgA at the epidermal-dermal junction. One case also showed C3 deposition and one patient had circulating antibasement membrane zone antibodies in a titer of 1280. These data provide strong evidence that this condition belongs to the cicatricial pemphigoid-bullous pemphigoid spectrum of disease.

Aged↗
PubMed1977

[Tomodensitometric study of cerebral accidents causing acute hemiplegia in children].

Computerized Axial Tomography (C.A.T.) easily distinguishes between the two types of cerebral accident responsible for the two major categories of acute hemiplegia in childhood. 1) In hemiplegias which develop in association with hemiclonic status epilepticus (H. H. and H. H. E. syndromes), in the majority of cases there is an appearance of cortico-sub-cortical atrophy involving the whole hemisphere contralateral to the hemiplegia. This atrophy develops following oedema of the hemisphere which accompanies the initial status epilepticus and which is clearly shown by a very early T.A.C. 2) In congenital or acquired hemiplegias not associated with status epilepticus there is, in most cases, an appearance of cerebral infarction or, very rarely, haemorrhage. It is thus possible, from a physiopathogenic standpoint, to draw a clear distinction between these two major forms of acute infantile hemiplegia. The first (H. H. and H. H. E. syndromes) usually result from hemispheric atrophy which develops in association with a unilateral or predominantly lateral episode of status epilepticus, whilst the second group are usually the result of cerebral infarction.

Adolescent↗
PubMed1977

Central nervous system involvement in mycosis fungoides: pre mortem diagnosis by light and electron microsocopic study of the spinal fluid.

Involvement of the brain, spinal cord, peripheral nerves, meninges, and cerebrospinal pathways in mycosis fungoides manifests itself, clinically, as an obscure neurologic disturbance, occurring in patients with cutaneous manifestations of that disorder. Neurologic expressions of this particular cutaneous lymphoma are infrequently reported, in spite of the fact that many patients dying in the course of mycosis fungoides have pathologically demonstrable central nervous system, peripheral nervous system, and meningeal involvement. We report here a patient who incurred devastating neurologic illness as one of the initial features of the course of systemic dissemination of mycosis fungoides. Death occurred nine years after the onset of cutaneous illness. In this instance, cerebrospinal fluid cytologic studies established the diagnosis of nervous system involvement. Mycosis fungoides cells shed into the cerebrospinal fluid were studied by special techniques of light and electron microscopy. Brain scan abnormalities were present, which were clinically correlative with foci of brain involvement. The initial response of patient's nervous system illness to therapy was gratifying but unsustained, and she went on to fatal brain and multiple organ involvement with disseminated mycosis fungoides. The techniques of spinal fluid cytologic diagnosis, confirmatory of the etiology of disease in this case, may have practical appications in the diagnosis of otherwise obscure neurologic disorders.

Adult↗
PubMed1976

Classification criteria for systemic lupus erythematosus. Frequency in normal patients.

One hundred healthy women were examined prospectively during their annual physical examination for any of the preliminary criteria of systemic lupus erythematosus (SLE). No patient had more than three of the criteria; 50 (50%) had none. The preliminary criteria were effective in excluding normal patients. Three of 19 patients taking oral contraceptives had serum antinuclear antibody (ANA), whereas only one of 81 non-pill users had serum ANA (P less than .05). None of these patients with positive ANA had clinical evidence of SLE.

Adult↗
PubMed1976

[Study of epilepsy by computer controlled transverse axial tomography of the brain].

The value of computerized azial tomography of the encephalon is considered:--Firstly, in relation to the different electro-clinical varieties of epilepsy (essentially primary, secondary and partial) where it provides information of a high degree of precision concerning the topography, frequency and size of morphological abnormalties of the encephalon.--Secondly, in relation to the various aetiological possibilities (tumour, post-traumatic, post-ischaemic, post-infective, et cetera). This new method is of considerable to specify an aetiology almost unknown up to the present time: post-ischaemic occipital porencephaly secondary to perinatal or infantile occlusion of the posterior cerebral artery.

Adult↗
PubMed1976

Acrodermatitis enteropathico. Abnormalities of fat metabolism and integumental ultrastructures in infants.

Acrodermatitis enteropathica is a rare disease of childhood, characterized by periorificial and perioral dermatitis, acrodermatitis, diarrhea, and alopecia. Two patients were successfully treated with diiodohydroxyquin (Diodoquin). Lipid concentrations disclosed abnormal distribution of fats that resembled those of less mature infants fed diets low in linoleic acid even though the patients were actually on diets with high linoleic acid levels. Fatty acid distribution showed increased levels of linoleic acid that correlated with clinical improvement in the patient who was more ill. Skin fatty acids showed decreased levels of linoleic acid. Electron micrographs and histochemical staining disclosed increased lipids droplets in epidermal cells. Linoleic acid and zinc may have a role in the origin of the disease, and measurement of both skin and serum linoleic acid is suggested in the evaluation of its progress.

Acrodermatitis↗
PubMed1976

Production of epidermal acantholysis in normal human skin in vitro by the IgG fraction from pemphigus serum.

Normal human skin was maintained in organ cultures for several days in Ham's F-10 medium with good preservation of the epidermal cells. When the partially purified IgG fraction from the pooled sera of patients with pemphigus vulgaris or pemphigus foliaceous was added to this culture system, after 24 hr some evidence of epidermal acantholysis was seen. By 72 hr, extensive suprabasilar epidermal acantholysis had occurred in which the acantholytic cells were indistinguishable histologically from the acantholytic cells in biopsies from skin lesions of patients with pemphigus vulgaris. In the control cultures (i.e., F-10 medium or F-10 medium + normal human serum IgG), none of these changes was seen. Direct immunofluorescent staining of these explants using fluorescein-labeled goat antihuman IgG showed that by 6 hr binding of the pemphigus IgG had occurred in the intercellular cement substance of the epidermis. The staining intensity was maximal by 18 to 20 hr. When the pemphigus serum was fractionated by DEAE-cellulose column chromatography, three major IgG-containing peaks (presumably IgG) were eluted which bound to the epidermoid intercellular substance and caused acantholysis in culture. The complement system did not play a role in the antibody-induced acantholysis since complement was not included in this system and heating the reconstituted F-10 + pemphigus IgG for 1 hr at 58 degrees C did not destroy the acantholytic activity. Autoradiographic experiments showed that after about 2 days in culture the rates of incorporation of RNA and protein precursors in the suprabasilar cells in the presence of pemphigus IgG were reduced to less than 10% of the normal IgG controls, whereas these synthetic activities of the basal cells were only slightly affected. These observations lead to the proposal that it is the interaction of the pemphigus autoantibody(s) with the suprabasilar epidermal cell which initiates and possibly substains the process(es) of acantholysis.

Acanthocytes↗
PubMed1976

[The diagnostic importance of low-density lipoprotein (LP-X) for the diagnosis of cholestasis].

Based on the clinical, biochemical and morphological examination of a selected group of patients, the following may be said about low-density lipoprotein (LP-X): The LP-X test 1. proves to be a reliable method of examination for diagnosing cholestasis. It is a quick and simple test; 2. has a highly significant statistical relationship (x2 = 31,7) to the histological results and other parameters indicating cholestasis; 3. does not, however, distinguish between intra- and extrahepatic cholestasis and positive results do not allow any conclusion as to the etiology of the icterus; 4. makes it possible to diagnose cases of cholestasis with aP activities not clinically manifest; 5. in borderline cases conclusions may be drawn from a combination of LP-X and aP results and, most of all, from LP-X and gamma-GT, a highly sensitive, specific and simple method of diagnosis. 6. diagnostic findings of still greater significance resulting from applying laboratory data indicating or precluding cholestasis may be derived from a prospective study with a larger group of patients, using the same parameters and taking the likelihood ratio into consideration.

Cholangitis↗
PubMed1976

Gluconate zinc in acrodermatitis enteropathica.

Two children with characteristic findings of acrodermatitis enteropathica were found to have low serum zinc levels prior to therapy. Treatment with zinc gluconate in low dosages resulted in an increase in serum zinc levels and clinical improvement. All family members studied had low serum zinc levels. In addition, we noted a change of hair color to red and excessive drooling just prior to exacerbations in these two patients. The hair color returned to normal with remission.

Acrodermatitis↗