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Biomedical subjects

D Michaeli

Publications and source records attributed to D Michaeli.

At least 73 records · Page 4Linked to original sources
PubMed1984

The immunogenicity of injectable collagen. I. A 1-year prospective study.

With the growing use of collagen-based biomaterials, questions have been raised regarding the immunogenicity of this protein in humans. Currently a bovine collagen implant is in widespread use for the correction of dermal contour deficiencies ( Zyderm Collagen Implant (hereafter referred to as "the implant"); Collagen Corporation, Palo Alto, CA). To investigate potential immunologic consequences of this material, sixty-one subjects were evaluated in a 1-year prospective study. Two of the sixty-one subjects (3%) experienced localized, self-limiting inflammatory responses to the implant material; only in these two subjects could elevated levels of anti-implant collagen antibodies be measured by radioimmunoassay. These antibodies did not cross-react with human dermal collagen nor did they result in elevated levels of circulating immune complexes. Routine blood and urine testing failed to reveal any results of clinical significance. Thus, this protein displayed only weak antigenic activity in this study population.

Adolescent↗
PubMed1984

The immunogenicity of injectable collagen. II. A retrospective review of seventy-two tested and treated patients.

Sera were collected from seventy-two patients who had been exposed to a preparation of a bovine collagen implant in widespread clinical use for correction of dermal defects ( Zyderm Collagen Implant [hereafter referred to as "the implant"]; Collagen Corporation, Palo Alto, CA). Thirty-one of these patients had reported implant site reactions alone, thirty-five had reported generalized symptoms without implant site involvement, and six had reported implant site reactions accompanied by generalized symptoms. Results of a radioimmunoassay performed on these sera showed that elevated levels of anti-implant antibodies correlated significantly with localized responses at injection sites. Conversely, systemic complaints could not be correlated with either skin reactions or antibody titers. In previous clinical studies, increasing numbers of exposure to this material were not shown to increase the likelihood of an immune response developing at implant sites. Therefore, immune responses to this implant are typically localized reactions that manifest within the first two exposures to the implant material.

Adult↗
PubMed1984

A comparative study of infective endocarditis.

A survey of hospitalizations at the Chaim Sheba Medical Center, covering two nonconsecutive decades (1951-60 and 1970-79), included 213 patients (228 episodes) with infective endocarditis. The increase in the age of patients and in the frequency of atherosclerotic heart disease, as well as the introduction of techniques such as heart catheterization and open-heart surgery, are responsible for the differences in clinical course, microbiology and therapy. Despite the changed pattern, rheumatic heart disease remained the principal underlying disease in both periods and Streptococcus viridans remained the most common pathogen. Not a single case of drug addiction appeared in our material, despite its increasing frequency in Israel.

Adolescent↗
PubMed1983

An unusual pattern of arthritis dermatitis syndrome.

A 27-year-old woman presented with skin lesions and arthritis of the right knee of two days' duration. Her medical history was noncontributory and synovial fluid aspirated from the affected knee and a biopsy of a skin lesion were negative for gonococci. However, after methylene blue staining of cervical and urethral smears, intracellular and extracellular diplococci were demonstrated. Immunofluorescence showed deposits of immunoglobulin complexes of the skin section within the wall of blood vessels and dermal-epidermal junction. Treatment with ampicillin, 4 gm a day, resulted in resolution of the lesions and arthritis in two days. The need for cervical and urethral smears and for better, as yet unavailable tools for the diagnosis of the arthritis dermatitis syndrome, is emphasized.

Adult↗
PubMed1979

Direct evidence for a sugar transport mechanism in isolated vacuoles.

Sugar transport has been directly observed in isolated higher plant vacuoles for the first time. The latter were released from protoplasts isolated from the mesophyll of Pisum sativum L.Uptake of l-glucose by the vacuoles was very slight in comparison with that of the d-glucose analog 3-O-methyl glucose (MeG), indicating, first, that a highly selective sugar uptake mechanism is seated in the tonoplast; and, second, that the mechanism was functioning in the isolated vacuoles.MeG uptake was markedly sensitive to the pH of the medium, falling as the external pH rose. Addition of MgATP to buffered medium strongly promoted MeG uptake by vacuoles, but not by the protoplasts from which they were released. Treatment with the proton ionophore SF(6847) drastically reduced uptake by the vacuoles, but had a lesser effect on uptake by the protoplasts. The inhibitory effect of SF(6847) on uptake by the vacuoles was countered to a substantial degree by the addition of MgATP.The influence of pH, the stimulatory effect of ATP, and the ATP-reversible inhibition by SF(6847) all strengthen the conclusion that the observed sugar uptake reflected membrane function and was not due to a diffusional inward leak through damaged membranes.The results are discussed in the light of currently held concepts regarding the driving force for sugar transport.

Journal Article↗