Injection Of Thymidine Research Articles

Influence of scretin and pentagastrin on the circadian rhythm of cell proliferation in the intestinal mucosa in rats.

The effects of Secretin (3.5 U/100 g) and Pentagastrin (25 μg/l00 g) on cell renewal in jejunal mucosa was studied in male Wistar rats. The labeling index (LI), mitotic index (MI), and histogram of the distribution of labeled cells were measured at 4-hour intervals during 24 h after intraperitoneal injection of hormones and compared with results obtained in control animals. DNA label was obtained by injection of tritiated thymidine (70 μCi/100 g) 30 min before sacrificing the animals. The proliferation of intestinal cells in rats was marked by a circadian rhythm with a nocturnal peak of DNA synthesis. After Pentagastrin, the LI remained high for 16,20, and 24 h after injection, during the time the control levels diminished in the circadian rhythm. The normal MI and the enlargement of the zone of proliferation support the hypothesis of a stimulating effect of gastrin on intestinal cell renewal. After Secretin, the LI peak of the cycle was suppressed and the MI decreased, indicating an inhibiting effect of Secretin on intestinal cell renewal. Secretin and gastrin act as trophic factors on intestinal mucosa and produce opposite effects on cell proliferation.

Cell kinetic studies in patients with lung cancer.

Widespread application of intralesional tritiated thymidine injection to obtain cell kinetic data in lung cancer is described. Thymidine-labeling indices were obtained in 28 patients with lung cancer, and the data analyzed by histologic cell types. The mean and median labeling indices were highest in small-cell carcinoma of the lung. Mean values were significantly higher in the small-cell and in the large-cell undifferentiated carcinoma groups than in the adenocarcinoma and epidermoid carcinoma. On the other hand, a labeled mitosis curve in a patient with small-cell carcinoma yielded a duration of DNA synthesis of 18.8 h; not unlike those obtained for other solid tumors. According to our concepts of tumor growth, these findings suggest that the fraction of proliferating cells may be significantly higher in the small-cell and large-cell undifferentiated carcinomas than in the more differentiated cell types of bronchogenic cancer. Knowledge of the growth fraction of these cancers may have implications in directing therapeutic approaches and in interpreting features of the natural history of the disease.

The effect of chronic frictional stimulation on hamster cheek pouch epithelium

A controlled frictional stimulus, produced by a rotating brush, was applied daily to hamster cheek pouch for periods of up to 14 days. Pouch epithelium was examined for changes in histological appearance, and for alteration in the rate of cell proliferation as studied by injection of Vinblastine or tritiated thymidine. Specimens which had received seven or more daily applications of friction showed a marked increase in the thickness of the stratum corneum and an increase in the size and number of cells in the stratum Malpighii. There was a significant increase in the number of metaphase figures and labelled cells per unit length of rubbed epithelium. No significant difference in the length of the DNA synthesis phase was detected. The epithelial response to friction appears to be essentially similar to the epithelial response to other forms of physical or chemical trauma.

Studies of nonmigrating long-lived lymphocytes in rats: V. Presence and reactions to antigens after neonatal thymectomy

Neonatally thymectomized and sham-operated rats were given courses of hind foot pad injections of tritiated thymidine after immune stimuli, and the popliteal lymph nodes were examined for the presence of persistently labeled lymphocytes 32 days later. A larger proportion of labeled small lymphocytes was found in the nodes of thymectomized rats than in the nodes of sham-operated rats, indicating that a significant portion of the long-lived nonmigrating cells are B cells. In sham-operated rats given a course of tritiated thymidine after an immune stimulus with a Salmonella flagellin, labeled blasts appeared 3 days after secondary challenges with both the same or a serologically distinct flagellin. In neonatally thymectomized rats, a blastogenic response occurred after challenge with the same flagellin but not after challenge with the non-specific flagellin. Thus, in normal rats there are also long-lived nonmigrating T cells in primed lymph nodes, and these are the cells responsible for the nonspecific blasto-genesis seen in earlier experiments.

Etude autoradiographique des premiers stades du développement de l’ébauche du membre antérieur chez deux espèces de Chéloniens (Testudo graeca L. et Emys orbicularis L.)

ABSTRACT Autoradiographic study of early stages of the anterior limb-bud in two species of chelonian embryos Embryos of two chelonian species (Testudo graeca L., Emys orbicularis L.) from 20-somites stage to 34-somites stage, fixed 2–4 h after an injection of tritiated thymidine or uridine or leucine, then emulsion-exposed 12–14 days, showed the following results: These results are compared with results obtained in other reptiles and chick embryos, in the light of the theories on the role of the somites and of the apical crest in the development of the anterior limb-bud.

A Histological and Kinetic Study of an Ileal Conduit

Abstract Ileal mucosa used as a urinary bladder for a 9-month period has been studied in a patient with limited life expectancy. Several biopsies removed at intervals up to 48 hr after tritiated thymidine injection revealed a mucosa in various stages of atrophy characterized early by a reduction in villus number and size, and later by a decrease in the number of crypts. A labeled mitosis curve revealed an S phase of approximately 20 hr and a G 1 of greater than 21 hr. The replacement time for this mucosa based on the labeled index at 1 hr and the mitotic index was estimated to be between 10 and 15 days. Histological and kinetic similarities of this tissue to normal human colon were noted and the patchy atrophy contrasted with the conditions of atrophic small bowel.

Cytokinetics of the S-180 ascites tumor system.

ABSTRACTThe cytokinetics of the S‐180 mouse ascites tumor system was determined on Days 2, 4, 6 and 9 of growth. Studies included volume tumor growth, per cent labeled mitoses curves, and repeated injections of tritiated thymidine. It was possible to extrapolate the cytokinetic compartment values to Day 0 of growth. Results indicate that the growth fraction of the S‐180 system remains close to 1 throughout its growth, with progressive lengthening of G1, S and G2 times. Cell loss is minimal through 6 days but becomes significant thereafter. A theoretical growth curve constructed from cytokinetic values is similar to the actual volume growth curve.

Lichen simplex: morphodynamic correlates.

The rate of epidermal cell proliferation has been examined by autoradiographic methods in lichen simplex chronicus in sixteen patients. The corrected labelling index was found to be 25.9% in eleven biopsies removed 50 min to I h after intracutaneous injection of tritiated thymidine (i.e. similar to that in psoriasis). Twelve biopsies were removed 1–8 days subsequent to injection with tritiated thymidine, and in the autoradiographs that resulted it was found that the rate of travel of labelled cells was not fast as in psoriasis. The possible explanations for the finding of a labeling index similar to that of psoriasis but a slower transit time include; the presence of a greater epidermal volume in lichen simplex; the inclusion of‘high level labelled cells’in the labelling index; and epidermal damage from the trauma of scratching resulting in intra-epidermal cell death of labelled cells.

High resolution autoradiography of mycoplasmalike organisms multiplying in some tissues of an insect vector for clover-phyllody

It has been demonstrated previously that mycoplasmalike organisms, agent of cloverphyllody disease, progressively reached the different organs of the experimentally infected insect vector. The present high resolution autoradiographic study shows that, after a tritiated thymidine injection, the mycoplasmas are labeled in the digestive tract epithelium, the hemolymph, and the salivary gland. Consequently, mycoplasmas multiplication seems to occur at the different stages of the insect infection. It was found that the multiplication occurs both for intracellular and extracellular particles.

Durée de formation des cristaux protéiques intranucléaires de l'intestin moyen de Tenebrio molitor

The rate of formation of the crystals is the purpose of the present work in which the turnover time of the epithelium is evaluated by measuring the time required for migration of labelled cells from the crypts to the lining of the midgut. In insects killed a few hours after a tritiated thymidine injection, only the replacement cells of the crypts are labelled. If the insects are kept alive longer, the labelled replacement cells progressively migrate; 4 days after the injection all the nuclei of the midgut epithelium are labelled and notably the crystal-containing nuclei; therefore the whole epithelium has been renewed. Since the replacement cells of the crypts never contain crystals, these latter have been formed in less than 4 days.

Autoradiographic studies of lymphoid cells in the small intestinal epithelium of the mouse.

The labelling index of the lymphoid cell population in the small intestinal epithelium of the mouse was determined at various time intervals after single or multiple intraperitoneal injections of tritiated thymidine. The results show that the population is composed on both short-lived and long-lived lymphoid cells. The generation time of short-lived cells was estimated at 10–14 h. Although the long-lived lymphocytes appear to have a generation time in the order of months, the actual number of these cells present in the epithelium declines fairly rapidly with a half-life of approximately 7 days.

Spermatogenesis in some Australian marsupials.

Eight stages of spermatogenesis, based on cellular association, have been found in four species of Australian marsupials: Macvopus eugenii, M. rufogriseus, Trichosurus vulpecula, and Perameles nasuta. The cellular association are similar to those in eutherian mammals, and the frequency with which these stages occur in these marsupials are also similar. Following [3H]thymidine injections directly into the testis or into a testicular artery, the length of one cycle of the spermatogenic epithelium was estimated by autoradiography to be 17, 16, and 15 days for M. rufogriseus, M. eugenii, and T, vulpecula respectively; labelled spermatozoa first appeared in the urine 61 and 56 days after injection in M. eugenii and T. vulpecula respectively. From these data the minimum transit time through the epididymis can be calculated to be 13 and 11 days respectively. From the number of cells labelled in tubular cross-sections at different stages of spermatogenesis 1 hr after an intra-arterial injection of [3H]thymidine, it was concluded that at least four synchronized peaks of mitosis occurred in the spermatogonia of M. rufogriseus.

Regional variations in mouse skin : Quantitation of epidermal compartments in two different body sites

Regional differences of the epidermis of the ears and soles were determined in mice. The living portion of the sole epidermis (keratoblasts and keratocytes) was 31÷2 times thicker in the soles with only twice as many cells as in the ear. A larger size of sole epidermal cells was found, the corneocytes included. In vertical sections 40% of the living cells were found in the basal layer of the sole compared to 61% in the ear epidermis. Indication was given however that in the ear the basal layer was not homogeneous. Considering size and shape of the epidermal cells the true proportion of cells in each of the three epidermal compartments (basal cells, keratocytes, corneocytes) was made. The percentage of cells labelled by one injection of thymidine as determined by autoradiography was 5 times higher in the soles as compared to the ears. Post mitotic cells passed through the sole epidermis (living portion) in 6 days compared to more than 20 days in the ear. The data are discussed in relation to problems of epidermal homeostasis.

Mouse thymus-independent and thymus-derived lymphoid cells. I. Immunofluorescent and functional studies.

The simultaneous use on mouse lymphoid suspensions of heterologous antisera directed against thymus-derived (T) cell mouse-specific lymphocyte antigen and brain-associated theta antigen (MSLA and BAtheta) or thymus-independent (B) cell mouse-specific bone marrow-derived lymphocyte antigen (MBLA) surface antigens allowed direct proof of the different specificity of these antisera by double immunofluorescence (IF) staining with selective visualization of fluorochromes. These antisera and antisera against mouse Ig and its different types of chains were then used with technique of either double IF staining or IF combined with radioautography, allowing the following conclusions: (a) Surface Ig (sIg) was found exclusively on B cells and never on T cells, but not all B cells had sIg. Cells containing detectable amounts of Ig were MBLA+, but had less sIg than other B cells or none at all. There was evidence for the existence of a significant number of MBLA+ lymphocytes, neither bearing nor containing detectable Ig. (b) micro-Chains were the most frequent but not the only heavy chains found on spleen cells; however, it could not be decided with the technique used, if a single cell can bear more than one type of heavy chain. No cell containing gamma-chains was found to bear surface micro-chains, although a very few cells containing both micro- and gamma-chains were observed. (c) The antigen-binding cells detected after immunization with bacteriophage T4, bovine serum albumin, Maia squinado hemocyanin, and sheep erythrocytes were analyzed for MSLA, MBLA or sIg using double IF, a combination of IF and radioautography, or inhibition of "rosette" formation. Practically all the antigen-binding cells detected were MSLA-, MBLA+, sIg+. (d) More B cells than T cells were found among short-lived lymphoid cells labeled by repeated in vivo injections of tritiated thymidine, but the results did not support a simplified concept equating T cells to long-lived and B cells to short-lived lymphocytes. (e) Cells dividing rapidly in the lymph nodes draining the sites of immunization with various antigens were predominantly T cells 2 days after immunization and in majority B cells a few days later. (f) Incubation of lymphoid cells at 37 degrees C with rabbit anti-mouse Ig or anti-kappa chains led to complete disappearance of sIg and to decrease of MBLA ("antigenic modulation"). In the same conditions, anti-MBLA gave partial modulation of MBLA and of sIg; MBLA, however, reappeared much faster than sIg. No modulation of T cell surface antigens by the appropriate antisera was observed. Cell treatment with Pronase could remove MBLA, sIg, MSLA, and BAtheta, which reappeared within a few hours. Neuraminidase treatment was without detectable effect on these antigens.

Androgen-induced cell proliferation and differentiation in the seminal vesicle and coagulating gland of the castrated mouse.

SUMMARY Castrated male mice were injected with 250 μg testosterone propionate on 3 consecutive days. With the third injection, 1 μCi tritiated thymidine/g body weight was given intraperitoneally. A pulse-chase analysis in the seminal vesicle and coagulating gland was performed during the next 50 h and labelling and mitotic indices were obtained. One hour after the injection of tritiated thymidine the labelling index was 19% in the seminal vesicle and 13% in the coagulating gland. The mitotic index was 1·7% in the seminal vesicle and 1·4% in the coagulating gland. The observed cell cycle (Tc) duration in the seminal vesicle was 25 h, and the duration of DNA synthesis (ts) was 9 h. The calculated duration of mitosis (tm) was 0·6 h, the presynthetic duration (tG1) was 14·2 h, and the postsynthetic duration (tG2) 1·2 h. Forty-eight hours after testosterone propionate the growth fraction was 0·62 and a decycling ratio of 0·8 was calculated. In the coagulating gland Tc was 52·0 h, ts 9·0 h, tm 1·0 h, tg1 41·0 h and tG2 1·0 h.

The epidermal component of pityriasis lichenoides.

Summary.— The scaling papules of pityriasis lichenoides (PL) can at times simulate psoriasis clinically and histologically. In this study particular attention has been paid to the epidermal changes in PL, and 126 biopsy specimens from 94 patients were examined. Parakeratosis was found in 72%, invasion of the epidermis by mononuclear cells in 69%, and focal cell death in 57%. Skin surface biopsies from 8 patients and cryostat sections from 12 patients were examined histochemically. The parakeratotic scale and scattered individual keratinocytes within the epidermis demonstrated strong hydrolytic enzyme activity, and there was a diminution in the reactivity for mitochondrial enzymes within the PL papules. The labelling index was determined for 7 PL lesions after injection of tritiated thymidine and found to be 15·2%. In addition, slices of tissue from 8 PL papules were incubated with tritiated proline, and this manoeuvre also demonstrated the existence of dead and dying cells within the Malpighian layer. The suggestion is made that parakeratosis in PL is caused more by damage to the epidermis than by increased epidermopoiesis.

Cell proliferation kinetics in goldfish acclimated to various temperatures.

Cell proliferation has been studied in goldfish which have been acclimated to temperatures of 6, 10, 15, 20, 30 and 37°C. Hemopoietic tissue and intestinal epithelium show similar temperature effects, but they are seen more clearly in the latter. The fraction of intestinal epithelial cells labeled by a single injection of tritiated thymidine decreases as the temperature increases above 20°C. The total tissue incorporation of DNA precursor also decreases with increasing temperature. On the other hand, the grain counts per nucleus tend to increase slightly with increasing temperature. The mean generation time as indicated by the rate of DNA turnover (loss of 125I‐DNA) shows little if any change as the temperature increases above 20°C. These observations imply that in the rapidly proliferating cells of the goldfish the mitotic cycle is remarkably insensitive to temperature change, except for the DNA synthesis phase, which has a temperature dependence (Q10= 2.6) characteristic of enzyme‐mediated chemical reactions.

Cell proliferation kinetics in ascites sarcoma 180

The kinetic parameters of a 5-day growth of sarcoma 180 (ascites) have been determined, using both the labelled mitosis method after pulse labelling with 3H thymidine and the 3H and 14C thymidine double labelling technic. The two methods yielded reproducible results, labelling index 73 %; duration of the period of DNA synthesis (S phase) 13 hours (13.5 from double labelling: technic mitosis 0.24 (0.34) hours; G1 + G2 5.3 (4.76) hours; Te 18.5 (18.6) hours. The growth fraction obtained after repeated 3H thymidine injections was 0.95 and as calculated from the other kinetic parameters 0.98.

Cell kinetics in reticulum cell sarcoma.

A cell kinetic study is described in a large, superficial reticulum cell sarcoma (stem cell type) of the scalp. A percentage-labeled mitosis curve was obtained following an intravenous injection of tritiated thymidine. No second wave of labeled mitoses was identified. The median intermotitic time was estimated to be 50 hours with component phases, G1—30 hours, S—14 hours, and G2—5 hours. The overall labeling index of the tumor was 3.6%. Labeling was confined to cells which on their cytologic appearance were regarded as the tumor cell population. The modal DNA content of the tumor cell population was measured with a microspectro-photometer on Feulgen-stained material. The modal DNA content was hyperdiploid. Growth rate measurements in 10 patients with reticulum cell sarcoma are presented and discussed in relation to the results of the study.

Studies of Non-Migrating, Long-Lived Lymphocytes in Rats

Abstract Rat lymph node lymphocytes were labeled by hind footpad injections of tritiated thymidine in the absence of an immune stimulus or after priming with a polymerized Salmonella flagellin. Fifty or more days later the rats were killed and the lymph node cells were fractionated on continuous albumin density gradients. The proportions of lymphocytes of lighter density (< 1.07 g/cm3) were greater in primed than in unprimed nodes. The density distributions of the “long-lived” cells, i.e., those with persistent label, were identical to those of the total lymph node cell population. After challenge with either antigenically identical or different flagellins, the density distribution of the persistently labeled cells demonstrated relative loss of cells in the density range from 1.068 to 1.072 g/cm3 in comparison to the bulk of lymph node cells, but not in patterns distinct for the specificity of the antigens used for challenge. Comparison of the density distributions of long-lived lymphocytes with flagellinbinding cells and with cells transferring adoptive immune reactions revealed partial overlap with these cells from primed but not from unprimed lymph nodes.