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Biomedical subjects

E A Hudson

Publications and source records attributed to E A Hudson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Alterations in plasma and tumour levels of fatty acids with weight loss in an experimental cachexia model.

Growth of the MAC16 tumour in NMRI mice was accompanied by a decrease in host body weight, adipose tissue and liver weight in proportion to the tumour mass. The total plasma concentration of fatty acids also increased with increasing weight loss, while the linoleic acid: arachidonic acid ratio decreased. The liberated fatty acids were taken-up both by the tumour and the liver. However, since liver weight decreased in proportion to weight loss the accumulation of fatty acids increased as liver weight decreased. This suggests that the small liver mass had an increased capacity to accumulate fatty acids. The concentration of stearic, palmitic, oleic, palmitoleic and arachidonic acids all increased with increasing tumour weight, while the stearic acid: oleic acid ratio, a measure of unsaturation in the tumour increased. Thus mobilization of adipose tissue reserves during cancer cachexia ensures a constant availability of essential fatty acids for tumour growth.

Adenocarcinoma↗
PubMed1993

Kinetics of the inhibition of tumour growth in mice by eicosapentaenoic acid-reversal by linoleic acid.

Oral administration of eicosapentaenoic acid (EPA) (2.0 g/kg) by gavage to female NMRI mice bearing the MAC16 colon adenocarcinoma and with weight loss, prevented further loss in body weight and produced a delay in the growth of the tumour. Cell production and loss were determined by the [125I]5-iodo-2'-deoxyuridine method during the stationary and growth phase of the tumour in animals treated with EPA. Tumour stasis appeared to arise from an increase in the rate of cell loss from 38 to 71% without a significant change in the potential doubling time. During the subsequent growth phase the cell loss factor was reduced to 52% and this was combined with a reduced potential doubling time from 32 to 26 hr. The antiproliferative, but not the anticachectic effect of EPA could be reversed by oral administration of pure linoleic acid (LA), (1.9 g/kg) which acted to increase tumour growth by reducing the cell loss factor to 45%. Despite this reversal, incorporation of EPA into tumour cell lipids was not significantly different in animals administered with either EPA alone or combined with LA. This suggests that the antiproliferative effect of EPA in this system may arise from an indirect effect through the blocking of the catabolic effect of the tumour on host adipose tissue, which normally supplies fatty acids essential for tumour growth. This suggests that LA may be required by some tumours to prevent cell loss and that the catabolism of adipose tissue, which accompanies cancer cachexia effectively supplies this fatty acid to the tumour.

Adenocarcinoma↗
PubMed1991

Explant organ culture: a review.

Organ explant culture models offer several significant advantages for studies of patho-physiologic mechanisms like cell injury, secretion, differentiation and structure development. Organs or small explants/slices can be removed in vivo and maintained in vitro for extended periods of time if careful attention is paid to the media composition, substrate selection, and atmosphere. In the case of human tissues obtained from autopsy or surgery, additional attention must be paid to the postmortem interval, temperature, hydration, and cause of death. Explant organ culture has been effectively utilized to establish outgrowth cell cultures and characterize the histiotypic relationships between the various cell types within an organ or tissue.

Animals↗
PubMed1990

Transformed human bronchial epithelial cells (BEAS-2B) alter the growth and morphology of normal human bronchial epithelial cells in vitro.

Normal human bronchial epithelial cells (BE) and adenovirus-12 SV40 hybrid virus transformed, non-tumorigenic human bronchial epithelial cells (BEAS-2B) were cultured for 7 days in a serum-free hormone supplemented medium. BE cells after 3 days in culture were exposed to conditioned medium (CMt) from confluent BEAS-2B cells. By day 7, CMt-treated BE cells exhibited a lower colony forming efficiency (CFE), fewer cells per colony, and a reduced mitotic index (MI) and BrdU (bromodeoxyuridine) labeling index. CMt also enhanced the expression of a terminally differentiated squamous phenotype in BE cells. Cell free lysates from BEAS-2B cells (CFLt) had effects similar to CMt on the MI and morphology of BE cells. In contrast, CMt and CFLt did not inhibit the growth, or alter the morphology of BEAS-2B cells. Conditioned medium from BE cells (CMn) did not reduce the growth of BEAS-2B cells, and had little effect on the morphology of BE cells. In co-cultures, BE cells in direct contact with BEAS-2B cells had a lower MI (0.4-0.7 vs. 1.6%) compared with colonies of BE cells in these cocultures. The concentration of transforming growth factor beta (TGF-beta) in conditioned media from BEAS-2B cells (CMt) was increased 10-fold over that in CMn. TGF-beta is known to induce terminal differentiation in epithelial cells. These results suggest that the selective growth advantage of transformed cells over normal cells during human bronchial carcinogenesis may be related to the release of autocrine/paracrine factors (e.g., TGF-beta) from transformed cells, which down-regulates and terminally differentiates the normal cells.

Bronchi↗
PubMed1990

Long-term culture of human esophageal explants and cells.

Human esophageal epithelium obtained from intermediate autopsies (less than 12 h) was maintained as cell and explant cultures. In order to develop a serum-free, defined media culture model, several medias and additives were evaluated. The viability and differentiation of the epithelial cells cultured with serum-free, Keratinocyte Growth Media (KGM, Clonetics Co., San Diego, CA) was improved over that of esophageal cells and explants cultured in either serum-supplemented CMRL 1066 (OCM), serum-free additive-supplemented CMRL 1066, or cimetidine-supplemented CMRL 1066. The KGM component EGF was determined to be trophic for esophagus cells on the basis of findings of increased 3H-TdR labelling in KGM cultures when compared to control cells grown in KGM without EGF (KBM). The morphologic pattern of the cytoskeletal proteins actin, keratin, and vimentin were characterized in isolated cell populations. The intermediate filaments, keratin, and vimentin were co-expressed in these epithelial cells. Esophageal explant viability, differentiation, and outgrowth from 15 cases were also evaluated in dishes coated with basement membrane associated proteins. Explants cultured in these dishes were equally well-preserved and differentiated. There were no significant differences in the explant histology when there was protein coating of the culture dishes, although one case showed improved outgrowth with laminin coating. A main advantage for using this culture system is that the same medium (KGM) can be used for both the culture of explants and isolated epithelial cells. Future applications of this model include determining: (1) the effect different concentrations of EGF and calcium in the media will have on esophageal proliferation and differentiation, and (2) the role of different basement membrane associated proteins on the plating efficiency of either isolated or outgrowth epithelial esophageal cells.

Actins↗
PubMed1989

A 13C-n.m.r. investigation of the ionizations within an inhibitor--alpha-chymotrypsin complex. Evidence that both alpha-chymotrypsin and trypsin stabilize a hemiketal oxyanion by similar mechanisms.

13C-n.m.r. was used to investigate the structure of the inhibitor enzyme complex formed when alpha-chymotrypsin is alkylated by L-1-chloro-4-phenyl-3-tosylamido-[2-13C]butan-2-one. Two signals are detected. The one at 204.82 +/- 0.11 p.p.m. does not titrate from pH 3 to 9 and is assigned to alkylated methionine-192. The second signal titrates from 99.08 p.p.m. to 103.44 p.p.m. with pKa 8.67. This signal is assigned to a tetrahedral adduct formed between the hydroxy group of serine-195 and the inhibitor. The titration shift of the tetrahedral adduct is ascribed to the ionization of the hemiketal hydroxy group. It is proposed that the resulting oxyanion is stabilized by interaction with the imidazolium ion of histidine-57. It is argued that this interaction must raise the pKa of at least 70% of histidine-57 to greater than 11. On denaturation/autolysis of the inhibitor-enzyme complex neither of the signals associated with the intact complex is detected, but a new signal is observed that titrates from 203.52 p.p.m. to 206.08 p.p.m. with pKa = 5.27. This titration shift is assigned to the ionization of the imidazolium ion of alkylated histidine, confirming that the inhibitor has alkylated histidine-57. The significance of these results for the catalytic mechanism of the serine proteinases is discussed.

Alkylation↗
PubMed1987

Cell injury and regeneration of human epithelium in organ culture.

Human esophageal, tracheal, and pancreatic ductal fragments were collected at autopsy after a postmortem interval of 12 hours or less and maintained in explant organ culture for 30 days. The viability and growth of the explants was assessed by morphology, LDH enzyme release, and cellular outgrowth. The viability and growth of the bronchial explant epithelium was directly related to the postmortem interval. Esophageal epithelial regeneration followed the desquamation of the superficial cell layers. Pancreatic epithelia appeared to grow more slowly and with less outgrowth than the other tissues. Epithelial cell growth along the explant surface and onto the culture dish appeared to proceed through the well-characterized process that follows cell injury, i.e., flattening, migration, replication, and differentiation. Thus, sufficient numbers of viable epithelial cells capable of regeneration were present in routine autopsy epithelium, but there was considerable variation from tissue to tissue and case to case. The most effective and accurate approach to follow when evaluating and predicting the growth and viability of these explants is by using a combination of morphologic, enzymatic and biologic assays. Errors in the interpretation of viability are possible when only one assay method is utilized. These tissues grown in explant organ culture are suitable for studies on the mechanism and response of epithelia to cell injury, recovery and wound healing.

Bronchi↗
PubMed1987

Sperm morphology by image analysis compared with subjective assessment.

Human sperm heads were detected and tracked using semi-automatic image analysis. Six measurements of size and shape were computed from two samples of semen from each of 26 men. Subjective assessments of abnormal morphological forms were made on the same samples by two independent assessors. A formula for prediction of percentage abnormality was calculated from the results. The subjective assessment of abnormality was related primarily to the number of elongated heads and secondly to the number of small heads. Computed image processing provides an objective method for measurement of the morphological features of sperm.

Humans↗
PubMed1986

Morphometry of spermatozoa using semiautomatic image analysis.

Human sperm heads were detected and tracked using semiautomatic image analysis. Measurements of size and shape on two specimens from each of 26 men showed that the major component of variability both within and between subjects was the number of small elongated sperm heads. Variability of the computed features between subjects was greater than that between samples from the same subject.

Humans↗
PubMed1985

Studies on the mechanisms of altered exocrine acinar cell differentiation and ductal metaplasia following nitrosamine exposure using hamster pancreatic explant organ culture.

Syrian golden hamster pancreatic organ explants were treated with either methylnitrosourea (MNU) or N-methyl-N-nitroso-N'-nitroguanidine (MNNG). In control explants treated with only dimethylsulfoxide, there was evidence of autophagy and crinophagy in acinar cells. Carcinogen-exposed explants showed increased numbers of autophagic and crinophagic vacuoles. In long-term cultured explants there was an increase in the number of ducts over zero time control tissues. Eosinophilic cells similar to hepatocyte-like cells were seen in 90% of the carcinogen-treated explant experiments and in 45% of the controls. Nitrosamine exposure did not induce an increase in the overall amount of necrosis measured morphometrically. Nitrosamine exposure in vitro appears to lead to a sequence of events that follow carcinogen metabolism by the acinar cells. The changes that follow include altered cell morphology and toxic cell injury evidenced by autophagic and crinophagic processes, regeneration of ductal appearing cells, the appearance of hepatocyte-like cells and an overall increase in the amount of ductal metaplasia. Within some of these ductal foci, several ductules show atypical features.

Animals↗
PubMed1985

Immunocytochemical reaction of Ca1 and HMFG2 monoclonal antibodies with cells from serous effusions.

The Ca1 antibody was used in an alkaline phosphatase immunocytochemical method on cells obtained from 150 specimens of pleural and ascitic fluids. The results were compared with the routine cytology report based on the light microscopical appearances. The Ca1 antibody identified tumour cells in 51 of 57 specimens with malignant cells. The exceptions were four small cell carcinomas, one malignant lymphoma, and one adenocarcinoma. A further seven specimens reported as containing atypical cells but without conclusive evidence of malignancy were Ca1 positive. The Ca1 antibody did not give a positive reaction with benign mesothelial cells. Similar results were obtained with the HMFG2 antibody and malignant cells, but in eight of 18 benign effusions it reacted with mesothelial cells.

Antibodies↗