Biomedical subjects

K G Brand

Publications and source records attributed to K G Brand.

At least 37 records · Page 2Linked to original sources

PubMed1975

Suppression of bacterial growth and ammonia formation by citrate buffer in urine collected in ileal loop receptacles.

Bacterial growth in urine collected in ileal loop receptacles is greatly suppressed by the presence of 5 to 10 ml. 1-M. citrate buffer, pH 4. The suppression of bacterial growth by the citrate buffer prevents the formation of ammonia and perhaps other noxious metabolites whic are believed responsible for the irritation and inflammation of the skin exposed to infected urine. The citrate buffer is placed in the ileal loop receptacle at the beginning of each urine collection period.

Ammonia↗

PubMed1975

Foreign-body tumorigenesis: number, distribution, and cell density of preneoplastic clones.

Double 15 times 22-mm plastic films (two films on top of each other) were implanted subcutaneously in CBA/H-T6 mice. After 7.5, 8.5, and 9.5 months the films were removed. Each interior film (next to the abdominal wall), covered by a cell monolayer on one side only, was cut in four 7 times 10-mm segments. Wiping to 5 times 7, 4 times 4, 3 times 3, or 2 times 2 mm reduced the cell areas on three of them. They were then transferred to (CBA/H times CBA/Br)F1 or (CBA/H-Ty times CBA/Br)F1 recipient mice. Tumors arising from transferred film segments were analyzed as to chromosome number and morphology, sarcoma type, degree of anaplasticity, and posttransfer latency. We used these criteria to determine whether tumors originated from the same or different clones. From this information it was estimated that preneoplastic clones were present in limited numbers and that they were either widely disseminated or spatially restricted on the implant surfaces. The extent of clone dissemination appeared to be related to preneoplastic progression.

Animals↗

PubMed1975

Foreign-body tumorigenesis by vinyl chloride vinyl acetate copolymer: no evidence for chemical cocarcinogenesis.

We investigated whether vinyl chloride monomers, released from implants of vinyl chloride vinyl acetate copolymer (VCA), exerted cocarcinogenic activity and added thereby to the mechanism of foreign-body (FB) tumorigenesis. CBA/H and CBA/H-T6 mice were used. No evidence was found to indicate that chemical carcinogenic activity partakes in tumorigenesis by VCA implants. Hence it was concluded that VCA plastic is not suitable for the study of the combined process of FB/chemical cocarcinogenesis. Furthermore, experimental results obtained with VCA film implants were representative of FB tumorigenesis in the absence of demonstrable chemical carcinogenic activity.

Acetates↗

PubMed1975

Foreign-body tumorigenesis: in vitro isolation and expansion of preneoplastic clonal cell populations.

Foreign-body reactions were induced in coisogenic CBA/H and CBA/H-T6 mice by sc implantation of 15 times 22 times 0.2-mm unplasticized vinyl chloride vinyl acetate copolymer films. At 6 months' post implantation, implants and unopened tissue capsules were transferred to recipient animals of the T6-different partner strain. After another 3 months, part of the film/capsule complex was transferred to (C57BL/10ScSn times CBA/H-T6)F1 mice for tumor development. Capsule-derived and film-attached cells of the other part were separately cultured. Cultures consisting initially of euploid cells were often gradually replaced by different cells with specific aneuploid karyotypes which were identical with, or closely related to, those of the corresponding tumors. The cultured cells implanted in hybrid recipients at different passage numbers frequently gave rise to homologous tumors. Hence, it was possible to prepare in vitro cells with prefixed specific tumor determinants at different stages of preneoplastic maturation.

Aneuploidy↗

PubMed1975

Etiological factors, stages, and the role of the foreign body in foreign body tumorigenesis: a review.

Attempts were made to analyze the process of foreign body (FB) tumorigenesis and to identify etiologically significant factors by correlating information in the literature and recent experimental data from our labroatory. It appears that the process of FB tumorigenesis is dependent on sequence of specific conditions as expressed by the following criteria: (a) cellular proliferation and tissue infiltration during acute FB reaction; (b) fibrosis of the tissue capsule surrounding the FB; (c) quiescence of the tissue reaction, i. e., dormancy and phagocytic inactivity of FB-attached macrophages; and (d) availability of a FB surface for direct contact with clonal preneoplastic cells. There is no indication that the initial acquisition of neoplastic potential and the determination of specific tumor characteristics are based on direct physical or chemical reaction between cells and the FB. These etiological key events occur presumably in mesenchymal stem cells associated with the microvasculature no later than during the acute stage of FB reaction and certainly long before clonal descendants of these cells are first found in contact with the FB surface. In fact, there is no reason to assume that cells with neoplastic determination may be present in normal tissue prior to the introduction of a FB and that the FB would only create the conditions required for stepwise preneoplastic maturation.

Animals↗

PubMed1975

Foreign-body tumorigenesis induced by glass and smooth and rough plastic. Comparative study of preneoplastic events.

Foreign-body (FB) tumorigenesis was induced in female CBH/H and CBA/H-T6 mice and their hybrids by sc implantation of about 0.2-mm thick, large (660-720 mm2) or small (210-400 mm2) pieces of glass, smooth-surfaced plastic, or roughened plastic (rigid unplasticized vinyl chloride vinyl acetate copolymer). The tumorigenic process was analyzed in the various implantation groups by the evaluation of tumor incidences and latencies, and by the determination of 1) frequency of originator ("parent") cells, 2) appearance of preneoplastic cells in FB-reactive capsule tissue, 3) expansion of preneoplastic cell clones throughout the tissue capsule, and 4) pace of cellular preneoplastic maturation in terms of time remaining until neoplastic autonomy. Established methods included transfer of preneoplastic FB-reactive tissue capsules to recipient animals (hybrids of CBA/H and CBA/Br or C57BL/10ScSn). Specific preneoplastic events or stages of FB tumorigenesis were affected differently, depending on the size, material, and surface properties of implants.

Animals↗

PubMed1973