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Biomedical subjects

C T Hanks

Publications and source records attributed to C T Hanks.

72 records · Page 4Linked to original sources
PubMed1980

The expression of the epithelial blood-group substances: normal and malignant tissues.

The blood-group isoantigens are macromolecules localized to the plasma membranes of certain epithelial tissues. These substances are not detectable on the epithelium once it has undergone malignant transformation. Results of this investigation have demonstrated that the loss of detectability of the blood-group isoantigens does not appear to be related to a "masking" effect by an increase in surface sialic acid. Using fluorescein-labeled lectins specific for sugar subunits which are components of the blood-group oligosaccharide chain, it was found that the malignant cells and cells of the parabasal layer of normal oral epithelium had high levels of N-acetyl-D-glucosamine (GlcNAC), the subterminal sugar residue of the blood-group chain. The basal cells of normal epithelium and a minority of the malignant cells demonstrated levels of D-galactose-N-acetyl-D-galactosamine, which are the most proximal blood-group sugar subunits, as well as subunits of other membrane antigens. Our results indicate that malignant cells seem to be capable of synthesizing the blood-group oligosaccharide chains to the same level as the normal cells of the parabasal layer of stratified squamous epithelium. This level is just subjacent to the terminal D-galactose residue of the blood-group precursor chain. Increased or decreased differentiation characteristics of squamous cell carcinomas did not alter the level of blood-group synthesis. However, there may be a correlation between the level of synthesis of these antigens and the ability of the cells to demonstrate motility and to proliferate.

ABO Blood-Group System↗
PubMed1980

In vitro cytotoxicity of periodontally diseased root surfaces.

The purpose of this experiment was to develop a model system for controlled in vitro testing of root surface toxicity. Human gingival fibroblasts were placed into a depression created in the root surfaces of ten heat sterilized periodontally involved teeth, one half of which were root planed to remove all irritants. The teeth and fibroblasts were incubated in culture medium for 5 days, after which the cells were fixed and stained. Each tooth was examined for migration of cells onto the root planed and non-root planed areas of the tooth, and for evidence of any cytotoxic reaction. No difference in pattern of cell growth, cell migration, or cytotoxic reaction was discernible between root planed and non-root planed areas. Normal fibroblasts could be detected on the surfaces of dentin, calculus, periodontally involved cementum, and enamel. It appears that heat-sterilized periodontally-involved root surfaces, as well as calculus and calculus-laden enamel, were not toxic to human gingival fibroblasts in cell culture.

Cell Division↗
PubMed1978

The inhibitory effects of a dermal extract upon granulation tissue.

Injection of a water-soluble dermal extract into adult rats resulted in depression of DNA synthesis in granulation tissue at 3 different sites of injury, but not in epithelium. This suggests that connective tissue proliferation may be controlled in part by a chalone-like mechanism.

Animals↗
PubMed1978

Inhibition of connective tissue proliferation by dermal extract.

Following the subcutaneous injection of a water soluble dermal extract (DE) of neonatal rat skin into young adult male rats, depression of nuclear labeling (DNA synthesis) was observed in proliferating connective tissue in several wound sites. At 16--20 hr following DE injection, DNA synthesis was depressed most in back wounds (57--87%) and maxillary palatal wounds (45--68%), and least in ear wounds (24--29%). Epithelium in the wound margins of back, ear and palate did not show a similar depression in DE-injected animals. This study suggests that a chalone-like negative feedback mechanism may be partially responsible for in vivo control of fibroblastic proliferation in wound healing.

Animals↗
PubMed1977

Biochemical and morphological studies of rat submandibular gland: III. effects of testosterone treatment on proteins of granule-rickch fraction.

Mature adult male rats and castrated and testosterone-treated castrated adult rats were injected with pilocarpine HCl and 3-H-lysine and sacrificed sequentially over an eight-hour time period. Following homogenization and differential centrifugation, three subcellular fractions from each group of animals were analyzed by gel electrophoresis and liquid scintillation. Two proteins in the granule-rich fraction appeared in larger amounts on the densitometric scans and appeared to represent a larger proportion of newly synthesized proteins than the other proteins.

Animals↗
PubMedDate not supplied

Biochemical and morphological studies of rat submandibular gland: I. Centrifugal fractionation of granule-rich fraction.

Submandibular glands from male rats were homogenized in 0.34 M sucrose and 0.5 mM ethylenediaminetetraacetic acid in 10 mM HEPES buffer at a pH of 7.4. The extract was centrifuged and filtered through nuclepore filters to prepare a granule-rich fraction. Electron dense zymogen granules constituted approximately 85% of the particles in this fraction which also contained about a third of the total alkaline esterase activity in the gland.

Acid Phosphatase↗
PubMedDate not supplied

Biochemical and morphological studies of rat submandibular gland: II. Partial purification of proteins from granule-rich fraction.

Soluble proteins derived from a centrifuged and filtered granule-rich fraction of homogenized rat submandibular gland were analyzed by gel filtration, ion-exchange chromatography, and polyacrylamide gel electrophoresis. Both the granule-rich fraction and final supernatant fraction contained alkaline esterase activity. The major protein component, derived from granules of the convoluted tubules, was further resolved into a series of peptides ranging in molecular weight from 9,000 to 55,000 daltons.

Alkalies↗
PubMedDate not supplied

Element release and cytotoxicity of Pd-Cu binary alloys.

The release of elements from a series of palladium-copper alloys into cell-culture medium was measured using atomic absorption spectroscopy. The effect of the alloys on the succinyl dehydrogenase activity of Balb/c 3T3 fibroblasts was also measured. Palladium inhibited the release of Cu in alloys up to 70 atomic weight percent Cu. Below 70 at. % Cu, Cu release was < 0.8 micrograms/cm2 at 72 hours. Palladium release was lower from pure Pd (0.08 micrograms/cm2) at 72 hours than from Pd-Cu alloys containing > 70 at. % Cu, where it increased to 1.2 micrograms/cm2. The cytotoxicity of the alloys correlated closely with the release of Cu, becoming markedly cytotoxic above 70 at. % Cu, when Cu release was greater than 2.2 micrograms/cm2.

Animals↗
PubMedDate not supplied

Correlation between cytotoxicity and the elements released by dental casting alloys.

Elements that caused cytotoxicity of high-noble, noble, and silver-based dental casting alloys were identified by correlating the release of elements with the cytotoxicities of the alloys. Release of elements was determined by atomic absorption spectroscopy, and the cytotoxic effect was determined by cellular mitochondrial function. The high-noble alloy released low levels of elements that did not increase after 6 hours, whereas the other alloys released higher levels of elements that increased over time. The cytotoxic effects of the alloys were attributed primarily to the release of silver and copper. In some observations, interactions between silver and copper were suspected of having an effect on the cytotoxicity.

3T3 Cells↗