Transplantation of mouse mammary epithelial cells grown in primary collagen gel cultures

A technique for the transplantation of mouse mammary epithelial cells, grown in collagen gels, has been developed that demonstrates that the phenotype of the cells prior to culture was not altered by the culture conditions. Mammary epithelial cells from virgin and midpregnant C57BL/Crgl mice; virgin, midpregnant, and multiparous nonpregnant BALB/cfC3H/Crgl mice; a BALB/c hyperplastic alveolar nodule line, and mammary tumors from BALB/cfC3H/Crgl mice were embedded inside collagen gels and grown for 10 to 14 days in the presence of 25% swine serum plus cholera toxin (0.01 microgram/ml). The epithelial cells increased in number during the culture period. At the end of the culture period, the cells were removed from the collagen gels and transplanted to the gland-free mammary fat pads of 3-week-old syngeneic female mice. Culture in collagen gels increased the number of cells necessary to obtain a high percentage of mammary outgrowths as compared to cells not grown inside collagen gels. In general, mammary cells grown inside collagen gels gave rise to outgrowths, similar in phenotype to those from noncultured cells, and were representative of the tissue of origin. Mammary epithelial cells from C57BL/Crgl virgin donors grown in collagen gels for 10 to 14 days retained their ability to respond to the endogenous hormones of pregnancy and lactation of the host and formed lobuloalveolar structures full of secretion similar to the host's own mammary gland. The data indicate that the growth of mammary epithelial cells in collagen gels and subsequent transplantation into the gland-free fat pads of syngeneic hosts provides a simple system, wherein cells can be grown in vitro and their phenotypes determined in vivo.

Growth in primary culture of mouse submandibular epithelial cells embedded in collagen gels

Mouse submandibular glands were dissociated and the epithelial cells embedded in a collagen gel matrix. A characteristic and reproducible pattern of growth was seen resulting in three-dimensional outgrowths with ductlike structures projecting into the matrix. A sustained cell growth leading to a 5 to 10-fold increase in cell number was observed in less than 2 wk. The extent of this growth was found to be dependent on serum concentration. Of the three sera tested, swine serum was found to promote greater growth compared to fetal bovine serum or horse serum. Swine serum dose response studies have shown that a concentration of 2 to 5% in the medium elicited only a modest increase, if any, in cell number compared to the initial value within a period of 2 wk. Various hormones and growth factors were then added to this "maintenance" medium. Insulin was found to stimulate growth consistently and reproducibly in a dose-dependent manner. Ultrastructurally, the resulting outgrowths were comprised of polarized cells joined by apical tight junction and desmosomes. The outgrowths produced epidermal growth factor in response to dihydrotestosterone, triiodothyronine, and cortisol. The present system provides a method for sustaining growth and functional differentiation in primary culture of mouse submandibular gland epithelial cells.

Toxocara antibodies in veterinary personnel

The prevelance of antibodies to Toxocara canis was determined in 113 veterinary personnel from 22 animal clinics. One hundred and fourteen adult hospital in-patients served as controls. All participants completed a questionnaire supplying personal data and specifies regarding animal exposure and dog ownership. Antibodies to Toxocara were detected by enzyme linked immunosorbent assay (ELISA) employing as antigen, excretorysecretory products from second stage larvae of Toxocara canis.Toxocara antibodies were found in ten (8.8%) of 113 veterinary workers and in 11 (9.6%) of 114 controls. Antibody prevalence was no different between males and females. Toxocara infection was not associated with dog ownership in veterinary workers or in hospitalized controls. A breakdown of the specific occupations among veterinary personnel failed to show a difference in antibody prevalence, nor did years of service as a veterinary worker correlate with the presence of Toxocara antibody.Our results suggest that toxocariasis is not associated with direct humandog contact nor with occupational exposure to dogs.

The use of an excretory-secretory antigen for an ELISA specific sero-diagnosis of visceral larva migrans

In sera from patients with visceral larva migrans (VLM) syndrome, enzyme-linked immunospecific assay (ELISA) was used to detect IgG and IgE antibody anti-excretory-secretory antigen (ESA) from the second larval stage of Toxocara canis. The technical conditions of the assay were determined. The specificity of IgG ELISA-ESA (with OD values greater than 0.34) allowed the differentiation of VLM syndrome from ascaris or other human parasite infections.

Primary culture of human mammary epithelial cells embedded in collagen gels

Human mammary epithelial cells were dissociatd from mastectomy tissues. The contaminating fibroblasts were removed by the use of Percoll density-gradient centrifugation, which utilizes the difference in buoyant densities between epithelial cells and fibroblasts. A preparation highly enriched for mammary epithelial cells ws then embedded in collagen gel and cultured in Ham's F12 medium containing 12.5% horse serum, 2.5% fetal calf serum, 0.1 microgram cholera toxin/ml, an extract prepared from human male urine (L microgram protein/ml), and a hormone combination of 10 microgram insulin/ml, 10 microgram human placental lactogen/ml, 1 microgram aldosterone/ml, and 0.5 microgram hydrocortisone/ml. Sustained growth leading to an increase of tenfold to thirtyfold in cell number over the initial value was accomplished in primary culture, and this growth was maintained even after passage to secondary culture. Deletion of either the urine extract or the hormone combination resulted in less than optimal growth. Subsequent studies showed that hydrocortisone alone could replace the hormone combination. In addition, urine extract could be replaced by extracts prepared from human kidneys or brains. The collagen gel system provies a reproducible and consistent method for sustained three-dimensional growth of mammary epithelial cells from human breast tissue in primary as well as passaged cultures.

Growth factor- and cyclic nucleotide-induced proliferation of normal and malignant mammary epithelial cells in primary culture

Sustained growth of normal mouse mammary epithelial cells in primary culture, leading to an increase in cell number, in response to growth factors [epidermal growth factor (EGF) and fibroblast growth factor (FGF)] or cholera toxin has been achieved by embedding the cells inside collagen cells. Inclusion of agents known to increase the level of cellular cAMP have been found to be favorable for mammary epithelial cell proliferation. Cholera toxin is by far the best of all of the agents tested (prostaglandins E1 and E2, isoproterenol, theophylline, and dibutyryl cAMP). When growth factors (EGF or FGF) are added with cholera toxin, a synergistic effect resulting in a response much greater than with either of them alone is seen. This synergism was best seen in normal mammary epithelial cells from nonpregnant mice. The extent of this synergistic effect was found to be less in normal cells from pregnant mice, suggesting that these cells may be less responsive to EGF during pregnancy. Tumor cells were found to be rather inconsistent in their responses to EGF and cholera toxin, ranging from a minimal response, similar to that of normal cells from pregnant animals, to a maximal response, similar to that of normal cells from nonpregnant animals.

Primary culture of mouse mammary tumor epithelial cells embedded in collagen gels

Mammary tumor epithelial cells from BALB/cfC3H mice were dispersely embedded inside the collagen gels in Ham's F-12 medium containing horse serum. A sustained cell growth leading to a 5- to 10-fold increase in cell number over initial level was observed in less than 2 weeks. The extent of this growth was found to be dependent on serum concentration. However, addition of various protein and steroid hormones, both singly and in combination, to low-serum-containing medium failed to achieve a comparable level of growth to that promoted by higher serum concentration. Mammary tumor cells can now be consistently propagated in primary culture.

Sustained growth in primary culture of normal mammary epithelial cells embedded in collagen gels

Normal mammary epithelial cells from BALB/cfC3H midpregnant mice were freed from stromal cell types by Percoll density gradient centrifugation after collagenase digestion and were then embedded within collagen gels. Sustained growth leading to an increase in cell number was accomplished in response to cholera toxin and high concentrations of horse serum. The extent of growth was found to be dependent on the horse serum concentration, the maximum growth being attained at 50%. A serum concentration of 12.5% horse serum and 2.5% fetal calf serum, along with cholera toxin at 0.01 mug/ml, allowed maintenance but failed to cause any significant increase in cell number during the experimental period of 2 weeks. This same maintenance medium was used to determine the effects of various exogenously added steroids, protein hormones, and organ extracts on the proliferation of mammary epithelial cells in culture. Hormones failed to elicit any proliferative response, but extracts of kidney, brain, uterus, and spleen produced proliferative responses equal to or greater than the response obtained with 50% horse serum and cholera toxin. Kidney extracts prepared from midpregnant mice, virgin mice, and virgin mice given pituitary isografts all showed comparable activities, suggesting that the concentration of stimulatory factor(s) was not influenced by the hormonal status of the donor. Normal mammary epithelial cells that had undergone a 10- to 15-fold increase in cell number over initial values during 2-3 weeks in culture were passaged to secondary gel cultures. Outgrowth similar to those seen in primary culture were seen again in secondary culture. The present system provides a method for sustaining growth in culture of primary mammary epithelial cells from normal tissues.

Evaluation of enzyme-linked immunosorbent assay for the serodiagnosis of amebiasis

This report describes the development and evaluation of an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to Entamoeba histolytica. Highly sensitive and reproducible results were obtained in antigen-coated plates prepared by air-drying at 37 degrees C. Comparison of the ELISA with indirect fluorescent antibody and indirect hemagglutination techniques showed that the former was slightly more sensitive than the two latter methods. The specificity was evaluated by testing specially chosen population groups. ELISA was negative in 96.4% of 693 normal adults and children and in 96.6% of 377 patients with various parasitic, bacterial, mycotic, and other clinical diseases. The assay was positive in 26% of 461 patients with suspected amebiasis and in all of 53 patients with amoebic liver abscess. The ELISA was found to be a specific, highly sensitive, and reliable procedure for detecting anti-E. histolytica antibodies in humans.

Sustained growth and three-dimensional organization of primary mammary tumor epithelial cells embedded in collagen gels

We have developed a method for embedding cells within a collagen matrix which allows sustained growth of mouse mammary tumor epithelial cells in primary culture. A characteristic and reproducible pattern of organization and growth occurs: the cells rearrange themselves and produce duct-like structures extending into the matrix, resulting in a three-dimensional outgrowth. Autoradiography showed continuous [3H]thymidine incorporation during 8 weeks in culture. An increase in DNA content of the cultured cells as a function of time was observed. Mouse mammary tumor cells cultured in the conventional monolayer system failed to show any significant increase in cell number during a culture period of 6 weeks. In addition, in such monolayer systems, cells progressively became detached from the dishes in long-term culture. The mammary epithelial cell origin of the collagen gel cell outgrowths was shown by electron microscopic demonstration of polarized cells containing tight junctions and budding mammary tumor virus particles. In addition, in vivo transplantation of collagen gel outgrowths resulted in the development of mammary adenocarcinoma histologically similar to the donor tumor. Cellular outgrowth patterns resembling those from tumor cells were also seen in similar collagen gel cultures of normal mammary cells from mouse and human and of hyperplastic alveolar nodule cells from mouse. The significance and usefulness of this system in comparison to the conventional monolayer system are discussed.

The disposition of 3-methyl-2,3-dihydro-9H-isoxazolo[3,2-b]-quinazolin-9-one (W-2451)

3-Methyl-2,3-dihydro-9H-isoxazolo[3,2-b]quinazolin-9-one was readily absorbed, metabolized and eliminated in rat, dog, monkey and man. The radioactivity elimination after i.v. or p.o. administration of W-2451-14C in rats was biphasic with corresponding half-lives of 1.8 and 8.7 hours. Plasma half-lives of W-2451 in the dog, rhesus monkey and man were 1.4, 1.2 and 3.2 hours, respectively. In the rat, excretion via the urine was predominant, no significant accumulation in tissue occurred. The only major metabolite found in rat and dog urine, rat plasma and in the rat liver 9000 g supernatant fraction was the 3-hydroxy derivative of the drug. The unsaturated compound with the double bond in the 2,3-position and other hydroxylated metabolites were also present. Very little free or conjugated anthranilic acid and 3-(o-carboxy-phenylimino)-4-methylisoxazolidine were found.

Glucocorticoid regulation of prolactin receptors on mammary cells in culture

Mouse mammary epithelial cultures were examined for the ability to specifically bind [125I]PRL after cultivation on floating collagen gels. Corticosterone, particularly hydrocortisone, were effective in increasing the ability of mouse mammary cells to bind [125I]PRL. The absence of a glucocorticoid in the medium resulted in a loss of PRL binding during the 3 days in culture. 17 beta-Estradiol, progesterone, and aldosterone at equal molar concentration had no or only a small effect in increasing [125I]PRL binding.

Simultaneous production of casein and mammary tumor virus in mouse mammary epithelial cells grown on floating collagen gels

Simultaneous production of casein and mammary tumor virus (MTV) was analyzed in monolayer cultures of mammary epithelial cells from pregnant BALB/cfC3H mice. A comparison of the 2 cell culture substrata, plastic culture dish and floating collagen gel, showed that the latter supported a much higher degree of simultaneous casein and MTV production in the presence of insulin, cortisol and prolactin in serum-free culture medium. Importance of floating collagen gel was further shown by delaying the flotation of gels. When the release of gels was delayed, there were concomitant delays in the increase of casein and MTV production. These results indicate that hormones, nature of substratum and flotation regulate the degree of differentiation of mammary epithelial cells in vitro.

Hormonal regulation of cultured rabbit endometrial cells

A technique for culturing primary explants of rabbit endometrial cells in chemically defined medium has been developed. Diethylstilbestrol and natural estrogens were found to increase the rate of DNA initiation while progesterone had the opposite effect. Ultrastructural studies revealed that with estrogens, the cultures had the appearance of rapidly dividing cells having large euchromatic nuclei and prominent nucleoli, with aboundant free ribosomes in the cytoplasm. On the other hand, progesterone induced the formation of large multinucleated cells and also converted the cells to a more secretory type. When the cultures appear secretory, a protein called blastokinin (uteroglobin) is believed secreted. We have found that cultured cells synthesize blastokinin and progesterone is necessary for its continuous synthesis. The cultures were found to have receptors for the ovarian hormones and these receptors exhibited saturation kinetics. The dissociation constants for the receptors were also determined. A hypothetical model for the hormonal regulation of cell proliferation and differentiation is proposed.

Regulation of mammary tumor virus production by prolactin in BALB/cfC3H mouse normal mammary epithelial cells in vitro

Hormonal regulation of mammary tumor virus (MTV) production, has been analyzed with normal mammary epithelial cells from chronically infected BALB/cfC3H mice. The effect of prolactin in terms of increased MTV production was not reproducibly observed in cells cultured in tissue culture dishes, whereas the cells grown on floating collagen gels consistently responded to prolactin in a dose-dependent manner. Of the three media tested. Dulbecco's modified Eagle's medium was found to be the best in terms of responsiveness to prolactin and in maximal MTV production. Specificity studies with other pituitary and placental hormones in place of prolactin have shown that both growth hormones and human placental lactogen can replace prolactin, whereas follicle-stimulating hormone, luteinizing hormone, and thyrotrophin were ineffective. Contrary to the mammary tumor systems, where it has been shown that insulin and glucocorticoid can maximally stimulate MTV production, these hormones alone elicited only a small response in the absence of prolactin in normal mammary epithelial cells. Although prolactin alone had very little effect by itself, its presence was necessary (permissive effect) in order for the glucocorticoids to be able to maximally stimulate MTV production in normal cells.

A fixative for intestinal parasites permitting the use of concentration and permanent staining procedures

Results obtained with stools preserved in a simple, stable and relatively nontoxic fixative (SAF) composed of sodium acetate, acetic acid and formalin, suggest that this fixative is a suitable alternative to other fixatives for the preservation and recovery of intestinal parasites by diphasic concentration methods and permanent staining.

Cyclic AMP regulation of mammary tumor virus production

Addition of dibutyryl cyclic AMP (cAMP) and agents (isoproterenol and epinephrine) that stimulate the activities of adenylate cyclase enhance the stimulation of mammary tumor virus (MTV) production two- to threefold by glucocorticoid in short-term primary cultures of mammary tumors. This cAMP potentiation seems to depend on the stimulated level of MTV production by glucocorticoid alone, which increases MTV production 5- to 10-fold over basal level but varies greatly in absolute terms. When the stimulated level by glucocorticoid alone is suboptimal, cAMP seems to restore the sensitivity of the cells to the stimulatory effect of glucocorticoid to its maximum.

Dientamoeba fragilis: a review with notes on its epidemiology, pathogenicity, mode of transmission, and diagnosis

Dientamoeba fragilis was found in 4.2% of approximately 43,000 individuals who submitted stools for parasitological examination during 1970 to 1974. The parasite was more frequently found in the younger age group (less than 20 years) than in older age groups, and more often in females than in males. Symptoms in 255 of patients in whom D. fragilis was the only parasite found and for whom detailed symptoms had been supplied, included: diarrhea, abdominal pains, anal pruritus, and loose stools. Analysis of mixed infections of D. fragilis with intestinal helminths suggests that such infections are random except for the combination of D. fragilis and Enterobius vermicularis. This combination occurred 9 times more often than theoretically expected. Daily periodicity and distribution of D. fragilis within stools of one patient were studied over a period of 6 months. More than twice as many organisms per ml of stool were present in the last than in the first portion evacuated. The total number of organisms excreted fluctuated markedly from day to day.

Celestine blue B stain for intestinal protozoa

The use of an iron alum lake of celestine blue B in acetic acid as an alternative to hematoxylin in the routine staining of fecal smears and tissue sections for Protozoa is presented.

Effects of pancreozymin, urecholine and actinomycin D on the metabolism of ribonucleic acid by canine pancreas

1. Canine pancreas slices were incubated with [6-(14)C]orotic acid and the rate of its incorporation into RNA was measured. RNA was fractionated by shaking homogenates with phenol at 2 degrees , 50 degrees , 65 degrees and 80 degrees . Cytoplasmic RNA was extracted at the lowest temperature and nuclear RNA at the higher temperatures. The samples were centrifuged through sucrose gradients and the E(260) and (14)C-sedimentation patterns determined. Incorporation of orotic acid was very rapid into cytoplasmic 4s RNA. This probably represents end-group turnover. No incorporation into cytoplasmic ribosomal RNA was observed. 2. The nuclear 50 degrees -RNA exhibited two E(260) peaks, at 18s and 28s. This portion of the sample contained but moderate amounts of [(14)C]RNA. The highly labelled material had sedimentation coefficients in the range 35-50s. The nuclear 65 degrees -RNA showed an E(260) peak at 16s. The [(14)C]RNA peak occurred at 25-35s and this portion demonstrated the highest specific activity of any RNA fraction. 3. The 50 degrees -RNA, 65 degrees -RNA and 80 degrees -RNA were hydrolysed and their base compositions were determined. All three samples possess a ribosomal type of composition (G+C)/(A+U)=(1.4-1.7). For this reason they are considered to contain ribosomal precursor RNA as their major constituent. 4. Actinomycin D (0.5mug./ml.) in the incubation medium inhibited incorporation of orotic acid into both nuclear fractions but not into 4s RNA. 5. The cholinergic drug Urecholine inhibited incorporation into the heavy, high-specific-activity portions of the nuclear fractions but did not inhibit incorporation into the ribosomal precursor type of nuclear RNA. A similar result was also obtained with the hormone pancreozymin. Moderate inhibition of incorporation of orotic acid into 4s RNA likewise resulted from the presence of the drug and the hormone.