Search PubMed⌕ Search

Biomedical subjects

E Frenk

Publications and source records attributed to E Frenk.

At least 73 records · Page 4Linked to original sources
PubMed1991

Contour-clamped homogeneous electric field gel electrophoresis as a powerful epidemiologic tool in yeast infections.

To examine the longitudinal and cross-sectional patterns of yeast colonization in critically ill patients using genotypic characteristics defined by contour-clamped homogeneous electric field (CHEF) gel electrophoresis, 322 clinical isolates of Candida species were prospectively collected from 29 critically ill patients under routine surveillance over a 6-month period. All isolates, recovered from multiple anatomic sites and from the same sites on different days, were characterized by several identification methods (germ tube test), phenotyping (API system), and genotyping (electrophoretic karyotyping). Electrophoretic karyotype (EK) was determined using pulsed field electrophoresis with the CHEF technique. We used a karyotyping system for Candida albicans (EK code) that facilitated intraspecies delineation. C. albicans colonized 83% of the 29 patients. Candida sp. strains isolated from an individual patient had an identical EK pattern, even when isolated from different body sites, and remained the same over a prolonged period, up to 140 days. EK delineated not only the different Candida species, but also different strains of C. albicans. Strains of C. albicans isolated from different patients were distinguished using the EK pattern, but not API system. Minor variations in EK pattern could be demonstrated in a minority of strains recovered from four patients and were interpreted as chromosomal rearrangements between parent strains. Severe candidal infections, including eight episodes of fungemia, occurred in 11 of 29 patients (38%). All patients had been previously colonized with strains with identical EK patterns. Infection occurred a mean of 25 days after initial surveillance cultures grew yeast. No horizontal transmission could be demonstrated during the study period. In conclusion, EK is a reproducible, stable marker allowing inter-, as well as, intraspecies Candida strain delineation. EK strain delineation is a useful tool in candidal epidemiologic and pathogenic studies. Yeast colonization with the same strain preceded infection in critically ill patients.

Adolescent↗
PubMed1991

[Mycobacterium marinum granuloma in a fish fancier. Apropos of a case with sporotrichoid lesions].

A 43-year-old fish fancier with fish tank granuloma presented with a sporotrichoid-like skin infection of the right arm with multiple papulo-nodular lesions along the lymphatic drainage. Acid fast bacilli were found in skin biopsy specimens and Mycobacterium marinum grew in cultures. The clinical and histopathological findings in M. marinum infection are reviewed and the differential diagnosis, laboratory findings with this atypical mycobacterium, and therapeutic modalities are discussed. Finally, the importance of an adequate and pertinent patient's history for a correct and timely diagnosis is stressed.

Adult↗
PubMed1991

[Systemic lupus erythematosus associated with homozygous C2 deficiency. Apropos of a case report and literature review].

Inherited deficiencies of classical pathway complement components are rare and associated with autoimmune diseases and with increased susceptibility to bacterial infections. We report the clinical evolution and studies of the complement system in a 17-year-old female patient of Swiss origin presenting with systemic lupus erythematosus (malar rash, photosensitivity, leukopenia and antinuclear antibodies), in whom the hemolytically active second complement component (C2) was less than 10% of the normal value and antigenic C2 was not detectable. Linkage studies showed that the patient is HLA-A25, B18 positive and has the slow factor B allotype BfS. Further immunological assessment revealed low IgG4 concentrations in the patient, who had the G2M(23) allotype. The asymptomatic first degree family members had half-normal C2 levels compatible with a heterozygous state of C2 deficiency. Therapy with hydroxychloroquine for 17 months and topical sunscreen preparations produced marked clinical improvement. During the 4 years of follow-up, the patient has been well and shown only an abnormal titer of antinuclear antibodies. No infections were observed. To the best of our knowledge, 99 cases of homozygous C2 deficiency have been described so far and are discussed here.

Adolescent↗
PubMed1991

Isolation and characterisation of an extracellular alkaline protease of Aspergillus fumigatus.

Aspergillus fumigatus secreted an inducible alkaline protease (AlPase) when cultivated in the presence of collagen (200 micrograms/ml) as sole nitrogen and carbon source. Proteolytic activity was maximum at pH 9.0 with azocollagen as substrate. The enzyme, which was the major protein found in the supernate of a liquid culture, was purified by ammonium sulphate precipitation and gel filtration. The Mr was determined to be 33 Kda by gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The isoelectric point was estimated to be pH 8.2. Divalent cations strongly inhibited enzyme activity, whereas non-ionic detergents and reducing agents had no effect. A. fumigatus AlPase was totally inhibited by phenylmethanesulphonyl fluoride, antipain, chymostatin and alpha-2-macroglobulin. A. fumigatus AlPase is closely related to the A. oryzae AlPase, a serine protease of the subtilisin family, as attested by the antigen pattern seen by immunoblotting. The high collagenic activity and the ability of A. fumigatus AlPase to digest elastin could play a role in the invasion of the tissues by the fungus.

Aspergillus fumigatus↗
PubMed1990

The identification of pathogenic yeast strains by electrophoretic analysis of their chromosomes.

Epidemiological studies require characterisation of pathogenic yeasts at and below the species level. The chromosomes of 130 strains of four pathogenic species of the genus Candida, isolated from clinical material, were separated by pulsed field electrophoresis with the clamped homogeneous electric field (CHEF) technique. Each species was characterised by a distinct electrophoretic karyotype (EK). Furthermore, smaller variations of the EK amongst strains belonging to the same species appeared to offer a useful means of strain differentiation. A karyotyping system is proposed for C. albicans. The EKs were assigned to a code of four numbers which designated the number of bands that could be resolved in each of four sets of chromosomes. Morphotypes of the colonies of C. albicans on malt agar plates, which did not correlate with the EK, could provide a complementary means of strain characterisation in epidemiological studies.

Candida↗
PubMed1990

Nucleolar organizer regions in fibrohistiocytic tumors of the skin.

Nucleolar organizer regions (NORs) are loops of DNA which are present within the nucleoli of cells that possess ribosomal RNA (rRNA) genes. NORs are associated with proteins which can be visualized by a simple silver staining technique. As the number of NORs appears to reflect cell and nuclear activity its determination in benign, intermediate and malignant conditions could be of help in their differential diagnosis. In this study, we investigated 35 fibrohistiocytic tumors of the skin of benign, intermediate and malignant potential from 32 patients: 15 fibrous histiocytomas (FH), 5 FH with atypia (AFH), 7 atypical fibroxanthomas (AFX), 5 dermatofibrosarcoma protuberans (DFSP) and 3 malignant FH (MFH). A one-step silver technique was used on formalin or Bouin fixed specimens. Ag-NOR counts from benign conditions (FH, AFH) significantly differed from that of their intermediate-risk (AFX, DFSP) and malignant (MFH) counterparts. Furthermore, in 2 cases (one AFX; one MFH) which twice recurred, Ag-NOR counts steadily increased with time. However, a distinction could not be achieved between AFX and MFH. Although Ag-NOR is a simple and valuable technique, it does not allow a definite distinction between malignant and intermediate processes, at least as far as fibrohistiocytic tumors of the skin are concerned.

Diagnosis, Differential↗
PubMed1990

Delayed skin reaction caused by a coelenterate.

We report a delayed skin reaction, histologically characterized by liquefaction degeneration of the basal layer, which was observed in a 30-year-old man returning from Guadeloupe. It was most likely due to contact with a marine animal.

Adult↗
PubMed1990

Tufted angioma.

The clinical and histological description of 2 cases of tufted angioma is presented.

Diagnosis, Differential↗
PubMed1989

Spitz nevus (large spindle cell and/or epithelioid cell nevus). Age-related involvement of the suprabasal epidermis.

The Spitz nevus (large spindle and/or epithelioid cell nevus) is a benign acquired melanocytic tumour found predominantly in children and adolescents. Depending on the architecture (junctional, compound, dermal) and cytology (predominance of spindle or epithelioid cells, or presence of both cell types) several variants have been distinguished. A histological feature occasionally leading to diagnostic difficulties is the involvement of the suprabasal epidermis. The present study details the occurrence of intraepidermal involvement (pagetoid spread, nesting of cells, trans-epidermal elimination) according to the age of the patients. 89 cases of Spitz nevus were reviewed. There were 19 compound Spitz nevi with evidence of epidermal involvement, 56 cases of compound Spitz nevi without evidence of epidermal involvement and 14 cases of dermal Spitz nevi. The epidermal involvement mainly consisted of nesting of nevus cells above the basal cell layer, 9 cases clearly showing evidence of transepidermal elimination of cell nests. Upward spread of single melanocytes (pagetoid spread) was minimal and always associated with nesting or trans-epidermal elimination. The mean age of patients was significantly lower in the group of compound nevi with intraepidermal involvement (7.16 +/- 4.52 years), than in the group of compound nevi without epidermal involvement (13.18 +/- 8.88 years). The age of the latter group was significantly lower than the group of pure intradermal nevi (30.14 +/- 11.25 years). Thus, involvement of the suprabasal epidermis is not a feature of Spitz nevi in adults; in such a case the diagnosis of malignant melanoma should be considered.

Adolescent↗
PubMed1989

Thermolysin treatment: a new method for dermo-epidermal separation.

The epidermis of superficial human skin samples could easily be separated from the dermis following incubation at +4 degrees C for 1 h in a solution containing 250-500 micrograms/ml thermolysin, a proteolytic enzyme hitherto mostly used for protein analysis. Light and electron microscopy revealed that the dermo-epidermal separation occurred at the basement membrane between the sites of bullous pemphigoid antigen and laminin and that the hemidesmosomes were selectively disrupted. The cohesion and morphology of the separated epidermis as well as the immunologic parameters investigated were not altered by this procedure. The clear cut dermo-epidermal separation produced by thermolysin treatment differed from the separation obtained with trypsin, which predominantly occurred between basal and suprabasal cells by disruption of desmosomes.

Adult↗
PubMed1989

Direct mycological examination in dermatology: a comparison of different methods.

Direct examination for fungi in skin and nail scrapings can be done by light microscopy with or without staining, or by fluorescence microscopy using specific fluorochromes for the fungal cell wall constituents. The principal techniques described in the literature and two new methods (Congo red and Na2S-Blankophor P flüssig) were compared for their efficiency and rapidity.

Fluorescent Dyes↗
PubMed1989

[Menkes disease. Report of a case with pronounced involvement of connective tissues and changes in epidermal desmosomes].

The authors describe a patient who presented from birth on a severe involvement of connective tissues with pathological fractures, lack of auricular cartilage, hyperlaxity of fingers and cutis laxa with deep folds, all suggestive of derangements of collagen and elastin. Hypothermia at 24 hours of age should have already indicated the possibility of Menkes' syndrome. From the 3rd month on, the patient presents a neurological deterioration and a myoclonic epilepsy which is resistant to treatment. Craniocerebral tomodensitometry revealed, with time, a cerebral atrophy and subdural hematomas. Angiodysplasia of a coronary artery was seen at cardiac echocardiography. Undetectable levels of serum copper and ceruloplasmin, and an increased uptake of copper by fibroblasts in vitro confirmed the diagnosis of Menkes' syndrome. Electron microscopy of a skin biopsy disclosed a desmosomal anomaly in the epidermis. Desmosomes stay apart suggesting an alteration of the interdesmosomal cement.

Brain↗