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Biomedical subjects

K G Brand

Publications and source records attributed to K G Brand.

At least 19 recordsLinked to original sources
PubMed1993

Infection of mammary prostheses: a survey and the question of prevention.

Seventy-three plastic surgeons reported 60 early and late mammary implant infections among 54,661 implantations. Smooth, textured, and polyurethane-coated implants had similar infections rates (respectively, 0.06%, 0.16%, and 0.12% for augmentations and 0.6%, 0.4%, and 0.3% for reconstructions including revisions and expansions). Insertion routes and implant placements had no influence on infection rates. Causative bacteria included Staphylococcus aureus and S. epidermidis, Streptococci A and B, enterobacteria, Klebsiella, Pseudomonas, and mycobacteria. Most surgeons followed a regimen of topical and/or systemic prophylaxis. Some (approximately 20%) used the Dolsky insertion sleeve. Whereas smoking, obesity, and diabetes did not significantly predispose to infection, the following did: skin atrophy and scarring, corticosteroids in subglandular augmentation, additional simultaneous surgery, pregnancy, preceding lactation, and vigorous exercising, massage, and trauma postsurgically. Few late implant infections were recorded resulting from bacterial milk duct invasion or hematogenously from antecedent infection foci. The need for and the possibilities of preventive measures are critically discussed.

Female↗
PubMed1988

Foam-covered mammary implants.

Our investigations suggest that polyurethane coating of implants prevents longitudinal fibrosis, circumferential capsule formation, and contracture as long as the underlying smooth silicone surface remains firmly and completely covered. Although not studied extensively, our experimental observations give no indication that polyurethane-coated implants promote septic inflammation more so than uncoated implants. Polyurethane-coated implants are less tumorigenic in mice than uncoated implants. However, because humans are highly resistant to foreign body tumorigenesis in general, either implant type can be considered virtually noncarcinogenic in humans.

Animals↗
PubMed1984

Procedure for intrapleural implantation in mice by thoracotomy.

An intrapleural implantation procedure by thoracotomy was developed for application in mice. Animal survival was found to depend on the following: (A) slow induction and quick reversal of a pneumothorax by controlled pleural air injection and withdrawal, (B) keeping the pleura open for the shortest possible time by quick insertion of the implant and immediate tight closure with prepositioned sutures, and (C) use of the right, not the left, pleural cavity especially for maximum size implants which for a 30-gram mouse was 12 X 5 X 4 mm. Surgical and postsurgical mortality was below 5% (n = over 300).

Animals↗
PubMed1983

Fibronectin in foreign body-induced sarcomas and preneoplastic cells.

Foreign body (FB)-induced murine sarcoma cells and advanced preneoplastic cells as well as normal fibroblasts produce fibronectin (FN) in primary culture; cells at early preneoplasia do not. Hence, the neoplastic properties of FB-induced sarcomas do not depend on absence of FN. Temporary FN repression during early preneoplasia is associated with certain phenotypic cell characteristics.

Animals↗
PubMed1983

Chromosomal aberrations in foreign body tumorigenesis of mice.

Sarcomas were induced in 107 male and female isogeneic CBA/H or CBA/H-T6 mice by subcutaneous implantation of double films of unplasticized vinylchloride-acetate copolymer, 15 x 22 x 0.2 mm in size. Tumors were grouped by chromosome number. G-banding was performed on chromosomes of (a) 12 sarcomas, (b) 6 specimens of preneoplastic cells derived from foreign body (FB)-reactive tissues at 4, 6, 9, and 16 months postimplantation, and (c) 11 sarcomas which developed from clonal lines of the preneoplastic cells studied. Karyological analyses lead to the following results and conclusions: (1) Various derangements in chromosome number occurred in preneoplastic cells during early FB reaction at the time of, and possibly in causal relation to carcinogenic initiation. (2) Structural abnormalities of specific chromosomes (insertions, translocations, transpositions, etc.) were found as stable cell markers only during late preneoplasia. They may thus contribute to advanced tumor progression. (3) Ploidy deviations of specific chromosomes (secondary to the early derangements in chromosome number) were most frequently seen in chromosomes 1, 6, 7, 13, 15, 18, and 19; however, these latter aberrations were unstable and inconsistent both in vivo and in vitro.

Aneuploidy↗
PubMed1980

Risk assessment of carcinogenesis at implantation sites.

Of the 98 foreign-body or scar-related cancers reported in the literature, over 25 percent have developed within 15 years, and over 50 percent within 25 years. Substantial numbers of various implants have now been in place for 10 to 20 years. Since at least 25 percent of cancer cases should already have occurred, the low number actually observed permits the prediction that the incidence of cancers at implantation sites will remain low. This conclusion is supported by studies on 27 specimens of chronic foreign-body reactions against a variety of implants that had been in situ for 1 to 19 years. Employing a cell-culture technique previously developed for experimental mice, an attempt was made to identify specific precancer cells in the tissues. None were detected, in contrast to foreign-body reactions of mice, in which the incidence of foreign-body tumors is high.

Animals↗
PubMed1980

Effects of gonadectomy on foreign-body tumorigenesis in CBA/H mice.

Sarcomas were induced by sc implantation of unplasticized polyvinylchloride-vinylacetate films in gonadectomized and normal male and female CBA/H mice. Gonadectomy did not demonstrably influence tumor incidence and tumor latencies in males but significantly prolonged tumor latencies in females. The results suggest that estrogen influences the pace of foreign-body tumorigenesis in CBA/H mice.

Animals↗
PubMed1979

Schistosomiasis--cancer: etiological considerations. A review.

Evidence for a causal connection between Schistosoma haematobium-infection and carcinoma of the urinary bladder is discussed. A group relationship of schistosomiasis cancer to cancers as+sociated with asbestosis, foreign body implants, and cicatrization is suggested on the basis of several criteria. Results of experimental foreign body tmuorigenesis in mice are presented and elaborated in relationship to schistosomiasis cancer. Carcinogenic development at the cellular level is discussed with emphasis on the essential role of tissue-environmental conditions, especially fibrotic changes and macrophage quiescence.

Adult↗
PubMed1978

Foreign-body tumorigenesis in mice: DNA synthesis in surface-attached cells during preneoplasia.

(CBA/H X CBA/H-T6)F1 mice were given sc implants of unplasticized vinyl chloride acetate 15 X 22-mm copolymer films. The animals were pulsed with [3H]thymidine at various times during the 15 months following implantation. DNA synthesis occurred in the film-attached cell population, predominantly macrophages, throughout the preneoplastic phase in both females and males. Giant cells with fewer than 10 nuclei were labeled synchronously and asynchronously. No DNA synthesis was detected in giant cells with more than 10 nuclei. Previous studies have shown that phagocytic inactivity and ultrastructural signs of functional dormancy are characteristic for the foreign-body-reactive macrophage. However, this investigation demonstrated that the macrophage was not dormant with respect to DNA synthesis.

Animals↗
PubMed1977

Foreign-body tumors of mice: strain and sex differences in latency and incidence.

Sarcomas were induced by sc implantation of unplasticized polyvinylchloride acetate films in female and male mice of strains AKR/J, BALB/cJ, BALB/cWat, CBA/H and CBA/H-T6, C3H/HeJ, C57BL/10ScSn, C57BL/6J-bgj, C57BL/cdJ, DBA/-1J l/LnJ, LP/J, SJL/J, X/Gf, 129/J, and hybrids (CBA/H-T6 X AKR/J)F1, (C57BL/10ScSn x CBA/H or CBA/H-T6)F1, (C57BL/6J-bgj x C57BL/6J)F1. The strains and sexes showed marked differences in incidence and mean latency of resulting tumors. Crucial information was provided for the selection of appropriate mouse strains for the study of interrelationships between genotypes, defined somatic properties, and the multifactorial process of foreign-body tumorigenesis.

Animals↗
PubMed1977

Immunosuppression studies in foreign body tumorigenesis: no evidence for tumor-specific antigenicity.

Sarcomas were induced in CBA/H mice by sc implantation of 15 X 22 X 0.2-mm polyvinyl chloride vinyl acetate copolymer films. The animals were immunosuppressed with azathoprine, antilymphocyte globulin, or thymectomy. Sarcoma development was not accelerated in comparison to nonimmunosuppressed demonstrated in sarcomas of immunosuppressed mice. It was concluded that foreign body tumorigenesis in mice in neither associated with nor dependent on the emergence of tumor-specific transplantation antigens.

Animals↗
PubMed1976

Multiphasic incidence of foreign body-induced sarcomas.

Single or multiple plastic films (unplasticized vinyl chloride vinyl acetate copolymer) of different sizes and shapes were implanted s.c. in female CBA/H and CBA/H-T6 mice. Tumor incidence increased and accelerated with increased total surface area of multiple implants or with increased size of single implants. Tumor distribution curves over time were generally multiphasic. The profiles changed in proportionate relation to implant size. These findings indicate class differences between tumors according to latency. Since latency is known to be a predetermining characteristic of foreign body-induced tumors, class differences seem to exist at the originator cell level, reflecting diversity of intrinsic carcinogenic factors.

Animals↗