Thymidine Labeling Index Research Articles

Effects of gastric fundectomy and antrectomy on the colonic mucosa in the hamster.

The effects of gastric fundectomy and antrectomy on the colonic mucosa were studied in hamsters over 5 and 25 days. Sham-operated animals served as controls. Basal plasma gastrin concentrations were significantly increased after fundectomy and significantly decreased after antrectomy. Five days after fundectomy, there was a significant increase in scintigraphically determined colonic tissue [3H]-thymidine uptake and [3H]-thymidine labeling index of goblet cells, both of which were reduced 5 days after antrectomy. After fundectomy, the labeling index was maximal in differentiating-proliferative cells in the midportion of the colonic crypts, whereas the labeling index of the immature proliferative cells at the base of the crypts did not differ from that in the controls. On day 25, the crypt size and the number and percentage of goblet cells in the crypts were significantly increased in fundectomized animals. The number and percentage of goblet cells in antrectomized animals were significantly reduced on day 25. It is concluded that fundectomy in the hamster induces colonic mucosal hyperplasia with goblet cell proliferation, whereas antrectomy leads to retardation of colonic goblet cell proliferation.

A meta-analysis of reported correlations between prognostic factors in breast cancer: Does axillary lymph node metastasis represent biology or chronology?

A statistical overview of published results on correlations between various prognostic factors in breast cancer was undertaken. A distinction was made between clinical (or anatomical) prognostic factors--namely, axillary lymph node status and tumour size--and eight different biological prognostic factors. The latter included: tumour grade, oestrogen and progesterone receptor status, thymidine labelling index, DNA ploidy, S-phase fraction, epidermal growth factor receptor expression and c-erbB-2 gene amplification (or overexpression). 139 articles were eligible for review which reported a total of 432 individual correlations. A simple form of meta-analysis was employed: the counting method, in which the number of studies achieving a statistically significant correlation or not were counted. For each possible correlation examined, the proportion of studies showing a statistically significant correlation was calculated and an exact binomial 99% confidence interval determined for that proportion. If the 99% confidence interval included 5% (the proportion of correlations that would be expected to be statistically significant if the null hypothesis was true), it was taken as failing to exclude the null hypothesis of a zero correlation, while if it excluded 5% it was taken as rejecting the null hypothesis of a zero correlation. A broad agreement was found among published reports on the existence of a statistically significant correlation between the various biological prognostic factors in breast cancer. Of the 20 correlations examined, 18 had a 99% confidence interval excluding 5%, thus rejecting the null hypothesis of a zero correlation. On the other hand, a completely different result was obtained when reports on possible correlations between lymph node status and tumour size on the one hand and the eight biological prognostic factors on the other were analysed. Of the 16 correlations examined, 13 had a 99% confidence interval including 5%, failing to reject the null hypothesis of a zero correlation. These observations suggest the hypothesis that the prognostic influence of node status and tumour size cannot be explained by an analysis of the biology of breast cancer; and is compatible with the contention that axillary node status is merely a reflection of the relative chronological age of breast cancer.

Different proliferative responses of periportal and perivenous hepatocytes to EGF

Stimulation of DNA synthesis by EGF was compared in cultured periportal and perivenous hepatocyte populations. Periportal hepatocytes responded to EGF more sensitive (IC 50-values 20 vs 75 ng/ml) and with a higher maximal stimulation (420 vs 290%) than perivenous hepatocytes with respect to both [ 3H]thymidine incorporation and labeling index. The glutamine synthetase-positive hepatocytes responded much less to EGF than did the perivenous cells in general. The simultaneous presence of insulin increased the sensitivity for EGF predominantly in the periportal hepatocytes. These inherent differences in the growth potential of hepatocytes from different acinar localizations may contribute to different growth patterns across the lobules in normal and regenerating liver.

Stimulatory effect of insulin like growth factor II on DNA synthesis in the human embryonic cornea

By using an organ culture technique, corneal endothelial cells in human embryonic eyes could be stimulated to initiate DNA synthesis by exposure to insulin like growth factor II (IGF-II). The thymidine-labelling index doubled after IGF-II supplementation. However, this stimulatory effect was neither augmented nor abrogated by the simultaneous addition of Mannose-6-Phosphate. Nor did Mannose-6-phosphate stimulate DNA synthesis in the absence of IGF II. In contrast, the IGF II effect was partly counteracted by addition of an antibody that blocks binding to the IGF type I receptor. Taken together, this data suggests that IGF II stimulates DNA-synthesis in corneal endothelium by binding to the IGF type I rather than the IGF type II/ mannose-6-phosphate receptor.

Effects of Hormones on Tumor Growth and Immunoreactive Insulin–like Growth Factor–1 of Estrogen Receptor–positive Human Breast Cancer (MCF‐7) Transplanted in Nude Mice

The effects of estrogens and tamoxifen were analyzed on estrogen receptor–positive human breast cancer (MCF–7) transplanted into athymic nude mice. It was found that (1) the tumor growth and the proportion of 3H–thymidine –labeled cells were significantly increased in the 17β– estradiol dipropionate (E2) group, but significantly decreased In the tamoxifen (TAM) group with respect to the control group, and (2) the tumor content of insulin–like growth factor–1 (IGF–1) and the rate of IGF–1–positive cells were significantly lower in the E2 group, but significantly higher in the TAM group than in the control group. It was concluded that the tumor content of IGF–1 and the proportion of IGF–I–positive cells were inversely correlated to the tumor growth and the 3H–thymidine labeling index in vivo,

Feasibility and reproducibility of the [3H]‐thymidine labelling index in breast cancer

For several malignancies, autoradiographic evaluation of the S phase cell fraction by means of [3H]-thymidine ([3H]dT) has proved a valid prognostic tool which should be included in a 'risk factor profile system' to estimate prognosis in individual patients. However, its clinical implementation requires a methodological standardization, a high feasibility and an assessment of the reproducibility of results, within and between different laboratories. The recent availability of a kit for in vitro incubation with [3H]dT and histological fixation of solid tumour specimens has contributed to the methodological simplification and standardization of the technical procedure, increasing its feasibility in several institutions. For breast cancer, preliminary results from a quality control study promoted by the Italian Society of Basic and Applied Cell Kinetics (SICCAB) showed a high inter-observer reproducibility within (r = 0.96) and between different laboratories (r = 0.93). Moreover, on a series of 20 autoradiographic samples sent to 15 different institutions, only 2% of tumours shifted from one of the cell kinetic subgroups, defined using the median [3H]dT labelling index (LI) of 2.8% as a cutoff, to the other. In addition, a marked consistency of results was observed among the different Italian institutions involved in cell kinetic studies on breast cancers, both in terms of median [3H]dT LI values and basic correlations. Periodic assessment of the reproducibility of [3H]dT LI evaluation among different laboratories is needed, especially for institutions involved in multicentre clinical protocols based on cell kinetic characteristics.

Proliferative activity of gonocytes, Sertoli cells and interstitial cells during testicular development in mice

Developing mouse testis was studied from Day 14 post coitum (p.c.) until Day 35 post partum (p.p.) by [3H]thymidine autoradiography. The gonocytes proliferated actively at Day 14 p.c., the [3H]thymidine labelling index (L.I.) being 7.5%, and were quiescent from Day 16 p.c. up to the first day of life, when spermatogenesis started. The L.I. increased to 20% at Day 2 p.p. The L.I. for the Sertoli cells was approximately 20% before birth. After birth the proliferative activity decreased. After Day 11 p.p., the Sertoli cells showed their typical adult appearance. After Day 17 p.p. no labelled Sertoli cells were observed. The Leydig cells featured a very low proliferative activity up to Day 21 p.p. (L.I. of maximal 1.9%). At Day 29 p.p. there was a peak of 7.4% in L.I., followed by a sharp decrease to 0.35% at Day 35 p.p. The L.I. of mesenchymal cells decreased from 11.4% at Day 14 p.c. to 1.1% at Day 14 p.p. and remained more or less constant thereafter. The proliferative activity of myoid, endothelial and perivascular cells followed a similar course to that of mesenchymal cells, their L.I.s being high before birth (16, 12.5 and 19%, respectively, decreasing until Day 14 p.p. (0.6, 2.0 and 1.2%, respectively) and thereafter being more or less constant. There was an increase in the relative number of Leydig cells from approximately 4% of the total interstitial cell number at Day 14 p.p. to 29.5% at Day 35 p.p. At the same time, the relative number of mesenchymal cells decreased from 55 to 13%. The diameter of the seminiferous tubules showed a peak of 92 microns at Day 16 p.c., decreased to 44 microns at Day 1 p.p. and increased again to 204 microns at Day 33 p.p. These results show that, except for the Leydig cells, the proliferative activity of testicular cell types is highest during the pre- and early postnatal period. The major outgrowth of the Leydig cell population occurs around the fourth week after birth. The results are in accordance with the hypothesis that the mesenchymal cells are the progenitors of Leydig cells.

Proliferating cell nuclear antigen expression in central nervous system neoplasms

Proliferating cell nuclear antigen (PCNA) is a cell-cycle-regulated protein, which can be demonstrated in routinely fixed specimens. Studies on various tissues, cell cultures and neoplasms have shown that PCNA labelling index (LI) correlates with flow cytometry, tritiated thymidine LI, bromodeoxyuridine (BrdU) incorporation and Ki67 LI. PCNA LI may have prognostic value in various neoplasms. The present study concerns PCNA immunostaining in a series of neuroglial tumours. We demonstrate that there is a relation between PCNA LI and histological grade, and between PCNA LI and reported thymidine LI, BrdU LI and Ki67 LI. Pleomorphic xanthoastrocytomas and low-grade astrocytomas had the lowest LI, whereas metastases of small cell lung cancer and medulloblastomas had the highest LI. Glioblastomas sometimes showed a certain degree of intratumoral heterogeneity of distribution of immunostained cells. Intratumoral heterogeneity underscores the critical importance of representative sampling of central nervous system neoplasms for kinetic studies. As expected, PCNA LI are somewhat higher than tritiated thymidine LI, BrdU LI and Ki67 LI because PCNA is a marker of G1, S, G2 and M-phases of the cell cycle and not of S-phase only. In addition, because of its long half-life, PCNA may be detected immunohistochemically in cells that have recently left the cell cycle. The immunohistochemical evaluation of PCNA LI is easy to perform on routinely processed material, allowing retrospective studies. PCNA LI may be a useful tool in grading gliomas. However, its prognostic value must be validated by comparing PCNA LI with the follow-up of the neoplasms, and possibly with the responsiveness to anti-proliferative therapy.

Effect of energy substrate manipulation on tumour cell proliferation in parenterally fed cancer patients

The effects of isocaloric carbohydrate-based vs. fat-based total parenteral nutrition (TPN) regimens on cancer cell proliferation and host nutritional status were evaluated in 27 patients with tumours of the gastro intestinal tract consecutively assigned to receive for 14 days: a glucose-based (A) or a lipid-based (B) TPN formula, or an oral diet (C) isocaloric and isonitrogenous to A and B. Cancer cell replication rate was evaluated by thymidine labelling index (LI) on tumour samples before and at the end of each nutritional regimen. The number of replicating cells increased by 32.2% in patients receiving regimen A. LI decreased by 24.3% in patients given regimen B. LI values were slightly increased (+15%) in patients maintained on regimen C. Nutritional status remained within normal limits. None of the LI changes observed between and within the three arms of the trial were found to be statistically significant. Thus we failed to prove that glucose consistently stimulates or lipids inhibit tumour proliferation despite a trend in this sense.

Inhibitory effects of somatostatin on rat hepatocyte proliferation are mediated by cyclic AMP

Somatostatin (SS-14) is known as an antigrowth factor for a variety of cell types, including gastrointestinal mucosa, exocrine pancreas, lymphocytes, and some tumors. We have recently identified and biochemically characterized SS-14-binding protein on rat liver plasma membranes (S. E. Raper, P. C. Kothary, and J. DelValle, Gastroenterology 96: A408, 1989; P. C. Kothary et al., Digestion 46(Suppl 1): 58, 1990). We hypothesized that SS-14 may affect liver growth as well and investigated cellular mechanisms of this phenomenon focusing on the second messenger cAMP. Freshly isolated rat hepatocytes were plated on tissue culture dishes coated with Matrigel (laminin, heparan sulfate, and type IV collagen). The medium was not supplemented with serum or hormones. Either dibutyryl-cAMP (1 m M) or isobutylmethylxanthine (IBMX, 0.1 m M) was added in the presence or absence of SS-14 (10 n M). DNA synthesis was estimated by the rate of [ 3H]thymidine incorporation into DNA and by the labeling index (an autoradiographic measurement of the number of labeled nuclei). SS-14 significantly inhibited both [ 3H]thymidine incorporation and labeling index of rat hepatocytes stimulated by dibutyryl-cAMP or IBMX. SS-14 also inhibited intracellular cAMP accumulation stimulated by IBMX. We conclude that SS-14 exerts at least part of its antiproliferative effects via the adenylate cyclase system. Further study using other signal transduction systems may yield more information about mechanisms of hepatocyte growth.

Cell kinetics and tumor-associated antigen expression in human mammary carcinomas.

Twenty-six primary breast carcinomas were studied to evaluate cell proliferation as assessed by thymidine labeling index (TLI), and antigenic phenotype, as defined by immunohistochemistry using eight monoclonal antibodies (MAbs) to tumor-associated antigens (TAAs). The majority of tumors had low TLI values. Reactivity to MAbs B72.3, CC49, CC83 (anti TAG 72), COL-12 (anti CEA) and MOv2 (against a tumor-associated mucoprotein) was restricted to less than 50% of the tumors studied, while MAbs B1.1 (anti CEA), MBrl and MBr8 (to tumor-associated carbohydrates) reacted with greater than 50% of the cases. Correlations between expression of TAAs and proliferative activity showed that the tumors could be divided into three groups, two characterized by either high proliferative activity and absence of antigenic expression or low proliferative activity and strong antigenic expression, and the third showing no relation between these two biological features. We defined two antigenic phenotypes associated with specific cellular kinetics: one characterized by negative immunoreaction with MAbs, CC49, CC83 and COL-12 and high proliferative activity; the other characterized by intense immunoreactivity with these antibodies and low proliferative activity. The data suggest that cell proliferation and antigenic phenotype may define biologic subsets of breast carcinomas.

Growth factor stimulation of proliferating cell nuclear antigen (PCNA) in human breast epithelium in organ culture

Normal human breast explants were maintained in serum-free culture for 7 days in the presence of either insulin hydrocortisone and cholera toxin (I/H/CT), epidermal growth factor (EGF) or transforming growth factor-α (TGF-α). Explants were labelled with [ 3H]thymidine, fixed in methacarn and processed for autoradiography. Parallel sections were immunolabelled with anti-PCNA antibody and analysed with a CAS 200 image analyser. Thymidine labelling index (TLI) and PCNA expression produced similar results with both indices increased in response to I/H/CT, EGF and TGF-α. In sections double labelled for PCNA and autoradiography the majority of labelled cells were positive for both markers.

Prevention of stenosis after vascular reconstruction: Pharmacologic control of intimal hyperplasia — A review

Prevention of stenosis after vascular reconstruction: Pharmacologic control of intimal hyperplasia — A review

Thymidine Labeling Index Versus Ki-67

Journal Article Thymidine Labeling Index Versus Ki-67 Get access John S. Meyer, M.D. John S. Meyer, M.D. Chief Pathologist and Director of Laboratories St. Luke's Hospital Chesterfield, Missouri and Visiting Professor of Pathology Washington University School of Medicine St. Louis, Missouri Search for other works by this author on: Oxford Academic Google Scholar American Journal of Clinical Pathology, Volume 95, Issue 4, 1 April 1991, Pages 602–603, https://doi.org/10.1093/ajcp/95.4.602b Published: 01 April 1991

Relationship between c-erbB-2 immunoreactivity and thymidine labelling index in breast carcinomain situ

The relationship between the presence of the c-erbB-2 protein, demonstrated immunohistochemically with antibody 21N, and thymidine labelling index (TLI) has been studied in the in situ component of 70 cases of carcinoma of the breast. A significant association was found between high TLI and positive staining. Twenty of the 70 cases stained (29%) and of those that were stained 75% had a high TLI; 43% of those with a high TLI stained positively but only 14% of those with a low TLI stained positively. Strong correlations were seen between nuclear size and histological pattern and both 21N staining and TLI. The majority of carcinomas of comedo pattern with large nuclei were 21N positive and had a high TLI, whilst those with small nuclei and a predominantly cribriform/micropapillary appearance did not stain and had a low TLI. In tumours of mixed histological pattern there was less concordance between staining and TLI. The significance of these findings in relation to the biological behaviour of these tumours and their clinical management is discussed.

The expression of progesterone receptors coincides with an arrest of DNA synthesis in human breast cancer

Two main models to account for the heterogeneous expression of estrogen receptors (ER) and progesterone receptors (PR) in human breast cancer have been proposed: the clonal model and the stem cell model. The authors previously provided evidence supporting the stem cell model since it was found that most of the proliferating cells in ER-positive (ER+) human breast cancer lack ER and that the ER-negative (ER-) and ER+ subpopulations are interrelated. The authors have analyzed in eighteen ER+/PR+ primary breast tumors the simultaneous expression of ER or PR (by immunohistochemistry) and DNA synthesis (by autoradiography) after 30 minutes of 3H-thymidine incorporation. The authors demonstrated that: (1) the average numbers of ER+ and PR+ cells were similar (36.8 +/- 10.7% and 39.3 +/- 17.6%, respectively); (2) The thymidine-labeling indexes of the ER+, ER-, PR+, and PR- subpopulations were 0.53 +/- 0.69%, 0.74 +/- 0.49%, 0.21 +/- 0.21 and 0.94 +/- 0.54%, respectively; and (3) 75.2% of the DNA-synthesizing cells were ER-, and 88.8% of them were PR-. The authors conclude that the cellular subpopulations expressing ER and PR were not identical, and the expression of PR was associated with a lower rate of cellular proliferation than was ER expression.

Regional heterogeneity in breast carcinoma: Thymidine labelling index, steroid hormone receptors, dna ploidy

We examined multiple samples of 65 primary breast carcinomas larger than 1 cm in diameter for thymidine labelling index (TLI), DNA index (DNAI, a measure of cellular DNA content by flow cytometry), and estrogen (ER) and progesterone (PgR) receptors by radioligand-binding. One or more axillary metastases were also assayed in 11 patients. Two to 15 samples were successfully assayed for TLI from 59 tumors, 2-31 samples for DNAI from 61 tumors, and 2-15 samples from 55 tumors for ER and PgR. Criteria for heterogeneity were excess inter-sample variance in comparison with intrasample variance at the p less than 0.05 level for TLI and DNAI, and variation of clinically significant magnitude in assay results for ER and PgR. Sixty-one percent of tumors were heterogeneous for TLI, 26% for DNAI, 24% for ER and 40% for PgR. High TLI disposed toward heterogeneity for TLI itself (p = 0.06), for ER (p = 0.04), and for PgR (p = 0.007). Young age favored heterogeneity for TLI (p = 0.12), ER (p = 0.002), and PgR (p = 0.04). Heterogeneity for DNAI was not related to age and TLI status but was more common in larger tumors (p = 0.08). After consideration of relationships between TLI, age, size, ER and PgR, TLI rather than age appears to be the more important determinant of heterogeneity for receptors. High TLI could lead to heterogeneity through increased numbers of cell divisions that favor emergence of variant stemlines, or by causing local vascular and humoral disparities through rapid growth. Regional heterogeneity can explain erroneous prognostic predictions in approximately 10% to 20% of breast carcinoma patients. We recommend multiple sampling of large breast carcinomas and analysis of axillary metastases for study of tumor markers.

Benzoαaαpyrene-induced skin damage and tumor promotion in the mouse

Epidermal cell kinetics and DNA adduct levels, and skin morphological changes were measured following weekly topical applications for 29 weeks of high (16, 32 and 64 micrograms) benzo[a]pyrene (B[a]P) doses to female ICR/Harlan mice, in order to investigate the relationship of these parameters to the timing, incidence and morphology of the elicited tumors. During the tumor latency period, [3H]thymidine labeling index, mitotic index, epidermal cell stacking, incidence of pyknotic and dark basal keratinocytes and labeled mitoses were periodically measured, as were nuclear area and DNA content. DNA adducts in skin epidermis were measured by an ELISA method over a period of 9 weeks of single weekly applications of 64, 32, 16 or 8 micrograms B[a]P. There was an initial linear increase in DNA adducts with dose in the epidermis but the increase was much less steep above 32 micrograms/week. This did not correlate with the sharp rise in tumor response above the 32 micrograms/week dose rate. Cell kinetic changes in response to the 64 micrograms/week dose reached a plateau in the first few weeks of the tumor latent period. There was little epidermal hyperplasia but an associated dose-dependent increase in [3H]thymidine labeling index, mitotic index and incidence of pyknotic and dark cells. This evidence indicated that B[a]P produced extensive cytotoxicity and cell death with regenerative proliferation under these conditions. Giant keratinocytes occurred in all dose groups. Analysis of a labeled mitosis curve indicated that B[a]P produced a G2/M block. There was a marked inflammatory response in the dermis at all B[a]P doses. Mice were observed weekly for tumor formation. Virtually all of the tumors were papillomas on initial appearance and required an average of 8 weeks to convert to carcinomas. The substantial cell killing and regenerative proliferation, and the correspondence between the dose-response patterns for epidermal damage and tumors, together with the initial appearance of tumors in the benign form, a characteristic of the action of promoting agents, provided evidence that the tissue damage associated with the high dose levels of B[a]P used in this study reflected tumor-promoting activity in this mouse epidermal tumorigenesis model. The implication of the results for mathematical models of tumor formation are discussed.

Effect of high‐fat and low‐fiber meals on the cell proliferation activity of colorectal mucosa

Normal healthy volunteers (n = 43) were divided into four groups that received diets providing low or high levels of dietary fat (33 or 96 g/day) and low or high levels of dietary fiber (6 and 41 g/day) for a period of five days. Proliferation was assessed with tritiated thymidine labeling of three rectal biopsies. After five days on the prescribed diets, the average thymidine labeling index (LI) of the group on the high fat-low fiber diet was only 25% higher than the average LI of the group on the low fat-high fiber diet, a difference that is not statistically significant. We conclude that a short-term increase in dietary fat and decrease in dietary fiber does not result in a large increase in cell proliferation rate.

In vivo manipulation of human breast cancer growth by estrogens and growth hormone: Kinetic and clinical results

Since 1983, a series of experimental and clinical studies have been carried out on the possibility of enhancing the chemotherapy effectiveness in breast cancer by expanding the fraction of cycling cells. Theoretically estrogens should recruit breast cancer cells and this fact should result in a higher killing efficiency of antiproliferative drugs. Actually it has been clearly shown, by means of the thymidine labeling index and primer-dependent α-DNA polymerase assay, that low doses of diethylstilbesterol are able to increase the tumor proliferative activity of human breast cancer in vivo (estrogenic recruitment). Three randomized trials have been carried out (one in locally advanced and two in metastatic breast cancer) comparing conventional polichemotherapy vs chemotherapy with estrogenic recruitment. Only limited advantages have been observed in these trials. Searching for new modalities of kinetic manipulation of tumors, recombinant human growth hormone has been employed in a pilot study: the preliminary results indicate that it largely enhances tumor proliferative activity, suggesting the possibility of employing a growth factor system to increase chemosensitivity.