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A J Ladman

Publications and source records attributed to A J Ladman.

18 recordsLinked to original sources
PubMed1988

Cell contacts and surface features of three murine tumors grown as multicellular spheroids.

Ultrastructural observations using scanning and transmission electron microscopy were made on three murine tumors, line 1 lung carcinoma, fibrosarcoma (FSA) and mammary carcinoma MCa-11, grown in vitro as multicellular tumor spheroids (MTS). The cytology of these MTS revealed the presence of characteristic cellular organelles as well as varying amounts of intracisternal type-A viral particles. In line 1 and FSA, the occurrence of gap junctions in the outer shells of these MTS was correlated with the growth behavior of these spheroids. In FSA, extracellular collagen bundles were identified next to tumor cells and represent synthetic activity by these cells under these conditions. No specific cytological correlations were made with the slow growing MCa-11 spheroid.

Animals↗
PubMed1981

A method for culturing canine tracheal smooth muscle cells in vitro: morphologic and pharmacologic observations.

A method of culturing canine tracheal smooth muscle cells in vitro is described. The morphology of these cells is monitored up to 60 days in culture and selected stages are illustrated. The characteristics of these cells are numerous mechanical attachments, the presence of thick filaments in suitably processed cells, and their contractile response to in vitro administration of carbachol, a cholinomimetic drug. They also possess nexus formations and both thin (actin) filaments and 10-nm filaments. Mitosis is found in the nonconfluent preparations up to 16 days after culturing. Cultures of 2 to 8 days appear to be most useful as pharmacological test vehicles. This system will be used to explore the phenomenon of adrenergic beta-2 receptor desensitization in airway smooth muscle, to attempt to localize these receptor sites and to determine how receptor affinity and/or number may be regulating cell response to pharmacologic agents.

Animals↗
PubMed1980

Multicellular tumour spheroids: a model for combined in vivo/in vitro assay of tumour immunity.

Multicellular tumour spheroids (MTS) from 4 mouse tumours (Line 1 lung carcinoma; a fibrosarcoma, FSA; a mammary carcinoma, MCa-11; and SV40-transformed fibroblasts, SV-A31) WEre injected into the abdominal cavity of normal, immunized or tumour-bearing syngeneic mice, recovered after 4-48 h, and their growth measured in vitro for 7-16 days. Both normal and immunized mice inhibited MTS growth, but there was no correlation between the two types of inhibition, suggesting that different immunological processes were involved. For example, the greatest inhibition by normal mice was seen for the weakly immunogenic MCa-11, and the highly immunogenic tumour, SV-A31, was only moderately inhibited. However, the summed inhibition of MTS growth in normal and sensitized hosts corresponded to the behaviour of tumours as s.c. transplants; i.e., was inversely related to the malignancy of the same tumours. The inhibition of MTS by mice bearing identical early tumours (FSA or MCa-11) was comparable to that in immunized mice. Histological sections of SV-A31 MTS in normal or immunized hosts revealed the infiltration of MTS by various types of host cells, mostly polymorphonuclears, macrophages and lymphocytes.

Animals↗
PubMed1977

A simplified method for production and growth of multicellular tumor spheroids.

A new technique, based on the growth of tumor cells in liquid media over an agar base, has been developed for the formation and growth of multicellular tumor spheroids. All of the 11 transformed cell lines tested formed multicellular tumor spheroids, while none of the 8 normal cell types tested did so. The advantages of the present technique over older methods include its simplicity, generality, and experimental flexibility.

Agar↗
PubMed1968

Morphological and lipid analysis of the alveolar lining material in dog lung.

Endobronchial saline lavage was used to obtain acellular material and cells from the dog lung. The centrifuged lavage fluid yielded a sediment consisting of an upper white layer and a lower brown layer. The white layer was strongly surface-active. It consisted of a mixture of lipids and proteins; the composition of the lipid portion was the same in three dogs. The predominant lipids were phosphatidyl choline, cholesterol, and cholesteryl esters; 75-88% of the fatty acids in each phospholipid fraction were saturated. Electron microscopy showed a strong morphological resemblance between the white layer and alveolar lining material in situ.

Animals↗
PubMedDate not supplied

Electron microscopy of insulin precipitates.

Morphologic characteristics of insulin precipitates were examined by both scanning and transmission electron microscopy. Insulin precipitate obtained after 1 wk of in vivo storage in an implanted dog reservoir was compared with insulin precipitate produced in vitro by isoelectric precipitation, acid-freeze-heat precipitation, and motion-induced precipitation. Insulin precipitate produced in vivo had several morphologic forms, with spherical-lamellar structures predominating. In vitro isoelectric precipitated insulin produced microcrystalline material, whereas acid-freeze-heat and motion-induced precipitated insulin were associated with elongated fibrils. The morphologic appearance of the in vivo precipitated insulin was not entirely reproduced by any of the three in vitro methods of insulin precipitation. We conclude that insulin precipitation in vivo is a process that may involve more than one of the known mechanisms by which insulin precipitates in vitro.

Animals↗