Calcium- and cyclic AMP-dependent chloride secretion in human colonic epithelia.

Three stable epithelial cell lines (HCA-7, HCA-7-Col 1 and HCA-7-Col 3) all derived from the same human adenocarcinoma have been cultured on collagen-coated Millipore filters. These epithelial monolayers have been used to record short circuit current (SCC) in response to of secretagogues. Similar monolayers, but grown on plastic dishes, were used for measurements of tissue cyclic AMP.

Accessibility of antigenic sites recognized by AUA1, HMFG1 and HMFG2 monoclonal antibodies: its influence on antibody binding of live cells.

We assessed the immunoreactivity of live and alcohol-fixed monolayers of HRA-19, a rectal adenocarcinoma cell line, to the monoclonal antibodies AUA1, HMFG1 and HMFG2. Differences in staining patterns between live and alcohol-fixed colonies were found. The well-polarized cells forming the centers of the monolayer colonies showed strong membrane staining when the cells were alcohol-fixed prior to AUA1 incubation, but showed no staining when the cells were alive during the incubation.

Establishment and characterisation of six human colorectal adenocarcinoma cell lines.

The establishment and characterisation (morphology, ultrastructure, tumourigenicity) of six cell lines from primary human colorectal adenocarcinomas is described. These lines were established from surgical specimens, from 49 unselected patients, without the use of 'feeder' cells, 'conditioned' medium or passage of cells in nude mice. The six cell lines exhibit considerable variation in morphology, CEA secretion and tumourigenicity in nude mice.

Endocrine differentiation by a human rectal adenocarcinoma cell line (HRA-19).

Colorectal epithelium is composed of a variety of cell types, including absorptive, mucous and endocrine cells. All of these cell types are thought to arise from stem cells located at the base of the crypt. However, the factors which control these differentiation pathways are poorly understood.

Kinin effects on ion transport in monolayers of HCA-7 cells, a line from a human colonic adenocarcinoma.

Using epithelial monolayers of HCA-7 cells, derived from a primary human colonic adenocarcinoma and grown on pervious supports, it is shown that responses to lysylbradykinin can be elicited from either side. It is proposed that kinin receptors are inserted into both apical and basolateral membrane domains.

Dome formation by a human colonic adenocarcinoma cell line (HCA-7).

A new cell line, HCA-7, has been established from a primary human colonic adenocarcinoma. The HCA-7 cells have an epithelial morphology by phase-contrast microscopy, they secrete carcinoembryonic antigen, and they form adenocarcinomas when injected s.c.

HLA-DR expression in a human colonic carcinoma cell line.

A human colonic carcinoma cell line (HCA-7) isolated from a well differentiated mucoid adenocarcinoma of the colon has been maintained in vitro for 3 years. It spontaneously synthesizes HLA-DR which is mainly intracytoplasmic. Stimulation with lymphocyte conditioned medium and recombinant gamma-interferon results in enhanced synthesis of HLA-DR and the appearance of the antigen on the cell surface.

Further characterization of corticotrophin releasing factor activity from a bronchial tumour.

The nature of corticotrophin releasing factor (CRF) activity secreted by a human bronchial carcinoid cell line was investigated. The CRF activity in incubation media exposed to bronchial tumour cells was concentrated by preparative high pressure liquid chromatography (HPLC). Analytical HPLC resolved the CRF activity into several different forms.

Secretion of corticotrophin releasing factor-like activity by a human bronchial carcinoid cell line.

The production of corticotrophin releasing factor (CRF) activity by human tumour cells in monolayer culture was investigated. The secretion of CRF activity by a bronchial carcinoid cell line was demonstrated using a rat pituitary cell monolayer system. The long-term production (5 years) of CRF activity suggested the synthesis and secretion of active factors by the tumour cells.

Studies on the corticotrophin releasing activity of a posterior pituitary extract.

The posterior pituitary gland is considered to be a source of a corticotrophin releasing factor(s) distinct from vasopressin. In this study, the corticotrophin releasing activity of a commercial posterior pituitary extract (Pitressin) and synthetic vasopressin were compared, using a perfused rat pituitary monolayer system. Pitressin was shown to have approximately twice the releasing activity than could be accounted for by its vasopressin content.

A dose interpolation routine for multiple dilutions in radioimmunoassay.

A method of estimating doses from multiple dilutions of an unknown sample in radioimmunoassay is described. It uses a computer program to minimise the root mean square error about a standard curve. The confidence limits of the estimates were evaluated from the sum of squares error as a function of dose.