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Biomedical subjects

N Forest

Publications and source records attributed to N Forest.

78 records · Page 5Linked to original sources
PubMed1983

Freeze-dried skin allografts. A human clinical and histological study.

Free gingival autografts still remain the most predictable method for creating attached gingiva. However, a need exists for sources of connective tissue other than the patient's own connective tissue. Yukna et al. have proposed freeze-dried skin (FDS) allografts as a substitute for gingival autografts. The purpose of the present study was to evaluate FDS allografts on humans, clinically and histologically. Ten FDS allografts and two free gingival (FG) autografts were performed on ten patients, two of them receiving both FDS and FG grafts. Clinical measurements were made before surgery, immediately after surgery and then 2 and 6 months after surgery. After 4 and 24 months, biopsies were performed on both FG and FDS grafts. Routine histologic staining was done. The results show a mean gain of attached gingiva of 0.32 mm with a range from 0 to 0.8 mm. Compared biopsies sections of FDS allografts and FG autografts show that the tissue obtained with the FDS allografts do not display the histomorphologic pattern of attached gingiva. The FDS allografts do not seem to represent a good substitute to free gingival autografts. However, they might be used successfully as a biological bandage.

Adult↗
PubMed1983

[Expression of the glycogenic response to insulin in cultured fetal hepatocytes].

In the present study, we used primary cultures of fetal rat hepatocytes which are highly suitable for studying the glycogenic effect of insulin and its regulation. After a lag in the period of culture in the presence of cortisol, glycogenic response to insulin developed together with a progressive accumulation of glycogen. When insulin was added, the rate of glycogen synthesis increased, becoming maximal after 2-3 h, due to the activation of the glycogen synthase system already present. Modification of glycogen precursors in the medium did not alter the amplitude of the insulin effect. The glycogenic effect of insulin was unrelated to that of glucose load and occurred after the formation of glucose-1-phosphate. This only happened when the cyclic AMP-dependent glycogenolytic system was not stimulated, since it was suppressed by low doses of glucagon. Insulin effect, which was time-dependent, ceased after 4 h. This corresponded to a desensitization of hepatocytes without any alteration in the specific binding of insulin. These variations in the glycogenic effect of insulin were likely due to different causes; one of these could be the first events following the interaction of insulin with its receptor.

Animals↗
PubMed1982

Collagen synthesis in mouse embryonal carcinoma cells: effect of retinoic acid.

In five lines of mouse embryonal carcinoma cells, PCC3/A1, PCC4, PCC4/Aza-R1, and F9, collagen synthesis was examined by immunofluorescence reaction using specific antibodies directed against collagen. All the embryonal carcinoma cell lines showed type IV collagen, and PCC7-S/Aza-R1 revealed the additional presence of type III collagen. When the F9 and PCC3/A1 EC cells were treated with retinoic acid and dibutyryl-cAMP, they differentiated into morphologically different cellular types. These cellular types showed new types of collagen. Thus, in treated F9 cells, type I, type III, and type V collagen were detected and in treated PCC3/A1 cells, type III and type V collagen were detected. In two established cellular strains, PYS-2 corresponding to parietal endoderm and 3TDM-1 corresponding to trophoblastoma, collagen was identified by immunological reaction and electrophoretic mobility. The trophoblastoma cell line was characterized by the production of type I, type III, and type IV collagen, whereas endodermal PYS-2 revealed type IV collagen.

Animals↗
PubMed1979

[Characterization of Mycoplasma salivarium in periodontal diseases].

Research for oral mycoplasms has been conducted on individuals affected with periodontal disease. In 66 out of 100 samplings taken from lesions distinctive or gingivitis, it has been possible to identify Mycoplasma salivarium, by means of specific culture medium and serological reactions. A good correlation has been established between the oral hygiene index and the presence of Mycoplasma salivarium. 80% of the samplings taken from the periodontal pockets of patients affected with chronic periodontitis have revealed the presence of Mycoplasma salivarium. There is a close connection between the stage of the infection and the depth of the pockets. The deeper periodontal tissues of 63 out of the same 100 subjects bear evidence of Mycoplasma salivarium, which, besides the processes already described in relation to bacteria, would come to imply a direct action of mycoplasms on the cell metabolism.

Adult↗