Mean Labeling Index Research Articles

Epithelial cell proliferation in the rectal stump of patients with ileorectal anastomosis for ulcerative colitis.

Epithelial cell proliferation in the rectal stump after ileorectal anastomosis for ulcerative colitis was studied in 19 patients. This was achieved through in vitro incorporation of tritiated thymidine in mucosal biopsies and radioautographic analysis of the number and position of labelled nuclei in the crypts. Rectal biopsies from nine unoperated patients with ulcerative colitis and from 10 controls, were processed simultaneously. Except for one, all patients were clinically in remission. The crypt length and number of labelled cells per crypt column were found to be similar in the rectal mucosa from the three groups of subjects. The mean labelling index, although low 8.9%, was higher (p less than 0.05) in operated patients compared with controls; but the dispersion of individual values was similar in both groups. There was an extension of the proliferative compartment towards the surface in 88% of unoperated patients and in 60% of operated patients. In addition, there was a shift of the major zone of proliferation from the lower to the middle third of the crypt in 17% of operated patients and from the lower to the upper third of the crypt in 14% of unoperated patients. No correlation was found between the labelling index and either the age of patient, the duration of disease or the period elapsed after ileorectal anastomosis. Interestingly, among operated patients with a colitis for over 10 years, 42% had a quite normal proliferative pattern with a corresponding mean postoperative period of 7.5 years.

The role of the macrophage in microvascular regeneration following brain injury.

Although macrophages are the earliest cells found in association with vessels in an area of cerebral injury, the role of this cell in the subsequent regeneration of the microvasculature is unknown. DNA synthesis in cerebral endothelial cells at the margin of injury of mouse brain was assayed by quantitation of the labeling indices from 3H-thymidine autoradiographs of normal animals and animals with X-ray-induced leukopenia. A mean endothelial cell labeling index of 10% in the irradiated animals was significantly lower than control animals (26.7%) (p less than 0.01). In vitro tissue culture studies utilizing peritoneal macrophages and cerebral endothelium were then used to isolate the endothelial response to macrophages and their products. Macrophage-conditioned media did not stimulate cerebral endothelial proliferation when evaluated by a growth factor assay, although this macrophage-conditioned media did stimulate DNA synthesis in fibroblasts and bovine aortic endothelium. A migration study of the cerebral endothelial cells utilizing an agarose technique showed enhanced random migration in the presence of macrophage-conditioned media compared to controls (p less than 0.01). The results indicate that macrophages do not directly stimulate proliferation of cerebral endothelial cells, but influence their migration. A loss of contact inhibition and subsequent DNA synthesis and replication may follow.

An autoradiographic study of the role of satellite cells and myonuclei during myogenesis in vitro.

Satellite cells and myonuclei of neonatal rat muscles were differentially labeled with 3H-thymidine according to the procedure of Moss and Leblond (1971). Minced muscles fragments containing either labeled satellite cells or labeled myonuclei were cultured until multinucleated myotubes grew out from the explants. Reutilzation of isotope released from degenerating nuclei was competitively inhibited by using a culture medium containing excess (0.32-0.41 mM) cold thymidine. after an 8-10 day growth period, the explants were fixed and prepared for autoradiographic (ARG) examination to determine whether labeled satellite cells or myonuclei had contributed to the myonuclear population of the developing myotubes. Counts were made of the number of labeled myotubes in the explants and compared with the number of labeled satellite cells and myonuclei in samples of the original muscle tissues fixed at the time of explantation. The original muscles showed a mean satellite cell labeling index of 51.7% and gave rise to myotubes with a mean labeling incidence of 40%. In contrast, myonuclear labeling in the original muscle tissues showed no correlation with subsequent myotube labeling. Only 3.4% myotube labeling was found in explants in which over 30% of the original tissue myonuclei had been labeled. Under conditions controlled for isotope reutilization, these observations confirm results of in vivo ARG studies indicating that satellite cells are the only significant source of regenerating myoblasts in injured muscle tissue.

Effects of prolonged moderate body deuteration on proliferative activity in major cell renewal systems in mice

To evaluate the effects of prolonged moderate body deuteration on incorporation of tritiated thymidine ( 3HTdR) into the DNA of major cell renewal systems, young adult mice were given drinking fluid containing 30 % heavy water for 7, 14, 21, 42 and 70 days. Control mice drank tap water. Three hours prior to sacrifice, 925 kBq of 3HTdR were injected intravenously. Following extraction of the bulk of the soluble activity with an aqueous formalin solution, the residual 3H-activity of the organs was assayed by liquid scintillation counting and by autoradiography. The total thymic 3H-activity and the thymic weight, particularly of the cortex, were significantly reduced in deuterated mice early in the course of the experiment. The fraction of labeled thymocytes diminished to less than one half of the control values of day 70. The 3H-activity of the bone marrow in deuterated mice was reduced to about 3 4 of control values. In contrast, the total 3H-activity of the small intestine, as well as mean labeling index and mitotic index of small intestinal epithelia, were not markedly altered in deuterated versus control mice. Drinking water containing 30 % of heavy water did thus not result in generalized, profound and progressive disturbance of 3HTdR incorporation in all the major cell renewal systems in the mouse. The thymus and, to a lesser extent, the bone marrow, were unquestionably affected, but the depression of 3HTdR incorporation did not increase markedly in the course of 10 weeks. In these terms, the toxicity of 30 % heavy water in the drinking fluid appears minor. This is of particular interest since exposure to similar concentrations is known to elicit immunodepressive and/or antineoplastic effects.

Cell population kinetics of thyroid follicular cells in infant rats.

T cell population kinetics of thyroid follicular cells in rats were studied by means of autoradiography and a statmokinetic technique. During the first fortnight after birth no significant changes in the mitotic index (MI) and labelling index (LI) were found. In the next 2 weeks a constant decrease in the number of proliferating cells occurs. In 10-day old animals 40% of the follicular cells were in the cell cycle (GF); 3.25 +/- 0.77 (SEM) % in the S phase and 0.18 +/- 0.04% in mitoses (MI). Day-night changes in the LI and mitotic rate (MR) indicated a peak value at 13.30 hours with a lowest value at 22.30 hours. The mean LI and MR averaged over the whole 24 hr were 3.1 +/- 0.1% and 122.2 +/- 18.1%, respectively. In 10-day old animals, using the fraction of labelled mitoses (FLM) method the median cell cycle time (TC) was 79 hr and the phase durations were TG1--64.6 hr, TS--8.2 hr and TG2--5.1 hr. The decrease in the number of proliferating cells with the age of the animals is considered to be a result of both cell cycle prolongation and in growth fraction reduction.

Estrogen receptor heterogeneity and the relationship between estrogen receptor and the tritiated thymidine labeling index in human breast cancer.

Tissue from 54 patients with breast cancer was analyzed for estrogen receptor (ER). From 38 patients, tissue from multiple tumor sites was analyzed to determine ER heterogeneity. In 13 patients (34%) both positive and negative ER values were obtained. ER negative (ER-) results were observed more frequently in metastatic lesions. In 28 patients both the ER and [3H]-thymidine labeling index (LI) were measured in the metastatic lesion. [3H]-Thymidine was administered in vivo. There was a positive correlation between ER positivity and low LI. The mean LI of 8 ER positive (ER+) tumors was 3.4 in contrast to a mean LI of 10.0 for 14 ER- tumors (p less than 0.01). LI of 6 mixed ER tumors (ER+/-) was intermediate (mean 5.7). High LI (greater than or equal to 8) was associated with decreased survival regardless of the stage of disease at the time of study. ER with LI may provide an improved basis for treatment selection.

The temporal relationship between glomerular cell proliferation and monocyte infiltration in experimental glomerulonephritis.

During the course of an accelerated form of anti-glomerular basement membrane nephritis in rats, the authors determined the temporal relationships between (a) glomerular hypercellularity, (b) kinetics of cell proliferation and (c) monocyte infiltration in glomeruli. Although glomerular hypercellularity was not appreciable or mild by qualitative histology, mean glomerular cell counts rose between days two and six of nephritis by up to 30% over controls. Cell proliferation in glomeruli was assessed 2 h after pulse label with3H-thymidine by determining histoautoradiographic cell labeling indices (LI) and by measuring the total radioactivity of isolated glomeruli (TGA). On day one, mean LI of cells in Bowman’s capsule was increased by 356% over controls and fell subsequently. LI values of tuft cells rose more gradually, reaching a maximum increment of 405% on day four. TGA also increased on day one and two, and peaked on day four. In additional rats, studied in parallel,3H-thymidine incorporation was measured 48 h after the pulse in order to allow time for the labeling and glomerular influx of monocytes derived from dividing extra-renal precursors. In rats sacrificed on the first day of nephritis, the prolonged labeling time did not result in further gains of tuft LI or of TGA over values obtained 2 h after the pulse. On day four, by contrast, the 48-h labeling time was associated with markedly higher results for LI and TGA than the 2-h interval. These findings indicated that the glomerular influx of labeled blood-borne monocytes was not appreciable on day one but increased markedly between day two and day four. This was supported by histochemical studies for non-specific esterase which revealed a similar time course for the presence of monocytes in glomeruli by showing few esterase-positive monocytes in the early stage and many after day two. The results demonstrate that this model of glomerulonephritis is characterized by markedly enhanced replication of intrinsic glomerular cells, beginning on the first day of the injury at a time when the glomerular influx of monocytes is inconspicuous. Increases of glomerular cell prolifertion become most pronounced over the following days when they are associated with a sizeable monocytic infiltrate. The prominent cellular response in glomeruli is revealed by the applied quantitative methods in the absence of histologically impressive glomerular hypercellularity.

Infectious Mononucleosis: Sequential Immunologic, Cytochemical, and Cytokinetic Studies on Single Lymphoid Cells in Peripheral Blood

AbstractSequential immunologic, cytochemical, and cytokinetic studies were done on single lymphoid cells in the peripheral blood of 6 children with infectious mononucleosis (IM) and 1 child with toxoplasmosis 1–2 wk after onset of symptomatology. The absolute number of AET-SRBC rosetting (E+) cells was increased in all patients; the absolute number of cells with surface IgM (sIgM+) was increased in 3 of 7 patients. On the average, 46% of all lymphoid cells were E+Ia+sIgM−, 35% E+Ia− sIgM−, and 5% E−Ia+sIgM+. Of the E+Ia+sIgM− cells, only 7% were shown to have a dot-like esterase reaction pattern. Of the E+Ia−sIgM cells, 17% were esterase positive. The mean labeling index of the former was 18.2%, the mean labeling index of the latter 4.4%. No proliferating sIgM4 cells were observed in the 6 children with IM. The esterase reactions and the labeling indices of suppressor-cytotoxic and inducer-helper T cells were similar to those of E+Ia−sIgM− and E+la−sIgM− cells, respectively. These results suggest that the vast majority of the atypical cells in IM corresponds to activated suppressor cells, while a minority appears to be proliferating helper cells.

Infectious mononucleosis: sequential immunologic, cytochemical, and cytokinetic studies on single lymphoid cells in peripheral blood

Sequential immunologic, cytochemical, and cytokinetic studies were done on single lymphoid cells in the peripheral blood of 6 children with infectious mononucleosis (IM) and 1 child with toxoplasmosis 1–2 wk after onset of symptomatology. The absolute number of AET-SRBC rosetting (E+) cells was increased in all patients; the absolute number of cells with surface IgM (slgM+) was increased in 3 of 7 patients. On the average, 46% of all lymphoid cells were E+la+slgM-, 35% E+la-slgM-, and 5% E-la+slgM+. Of the E+la+slgM- cells, only 7% were shown to have a dot-like esterase reaction pattern. Of the E+la-slgM-cells, 17% were esterase positive. The mean labeling index of the former was 18.2%, the mean labeling index of the latter 4.4%. No proliferating slgM+ cells were observed in the 6 children with IM. The esterase reactions and the labeling indices of suppressor-cytotoxic and inducer-helper T cells were similar to those of E+la+slgM- and E+la-slgM- cells, respectively. These results suggest that the vast majority of the atypical cells in IM corresponds to activated suppressor cells, while a minority appears to be proliferating helper cells.

Cytopathological effect of partial cystectomy of rats.

The effect of partial cystectomy on induction of DNA synthesis in the urinary bladder epithelium was studied in a total of 147 male F344 rats. DNA synthesis started 12 hours after 75% or 50% resection of the bladder, and reached a maximum at 48 hours with a mean labelling index of 15.8% after 75% partial cystectomy and 13.8% after 50% partial cystectomy. In these two groups the proliferative activity of bladder epithelial cells returned to normal after 2 weeks and 1 week, respectively. Cytodifferentiation of epithelial cells, observed by transmission and scanning electron microscopy, remained normal during the regeneration process.

Mucosal cell proliferation in duodenal ulcer and duodenitis.

Mucosal cell proliferation in the first part of the duodenum was studied in 24 patients using a tissue culture technique in which endoscopic biopsies were subjected to autoradiography after exposure to tritiated thymidine. Eight patients had a normal duodenum, eight had duodenal ulcer, and eight had symptomatic chronic non-specific duodenitis. The mean crypt labelling index (LI) in normal duodenum was 8.8 0.4% (SEM). Increased labelling indices of 15.6 +/- 1.7% were found near the edge of duodenal ulcers and 17.8 1.8% in duodenitis. Treatment with cimetidine reduced both the severity of duodenitis and the mean crypt LI. The LI of histologically normal duodenal mucosa distal to ulcer of duodenitis was similar to that of the control subjects' mucosa. The increased mucosal cell proliferation seen in severe duodenitis, either alone or associated with duodenal ulceration, suggested that erosions and ulcers arose when the crypts passed into 'high output failure' and were unable to compensate for further epithelial cell loss. There was no evidence in out study for a generalised failure of mucosal cell proliferation in duodenal ulcer or duodenitis.

The cellular reaction in glomeruli of rats with anti-glomerular basement membrane nephritis.

This work examines the cellular reaction in glomeruli of rats with an acute form of anti-glomerular basement membrane (GBM) nephritis. After intravenous injection of rabbit-derived anti-GBM serum, heterologous and, later, autologous IgG fixed to the glomerular capillary loops. From day 1 to 11 of nephritis, glomerular hypercellularity was not appreciable or modest by qualitative histology, whereas morphometric evaluation revealed mild but significant increases of glomerular cell counts as compared to untreated controls. Histoautoradiographic studies of renal tissue 2 h after pulse administration of 3H-thymidine served to determine the proportion of glomerular cells which synthesized DNA, indicating forthcoming cell division. The mean labeling index (LI) of epithelial cells of Bowman's capsule was 1.8% in controls, rose 4- to 5-fold on the first day of nephritis and fell gradually from day 2 to 11. LI to tuft cells was 1.9% in controls, peaked on day 4, and fell thereafter. Histochemical staining for nonspecific esterase, a marker of monocytes and macrophages, revealed that glomeruli of normal rats contain very few stained cells (mean: 0.2/tuft section). In the course of nephritis, a gradual increase of esterase-positive cells took place in glomeruli which reached a plateau on day 4 (mean: 5.5/tuft section), indicating an influx of migrating monocytes. It is concluded that the injury of this model of anti-GBM nephritis involves markedly enhanced proliferation of intrinsic glomerular cells associated with infiltration of monocytes. Such a prominent cellular response is revealed by the applied quantitative methods in the absence of histologically impressive glomerular hypercellularity.

The cell cycle kinetics of human breast cancer.

Cell kinetic parameters were determined in 32 patients with breast cancer following intravenous [3H]thymidine injection. The mean labelling index (LI) was 8.6, range 1.2 to 24.1. The LI increased significantly with increased stage of disease. The highest values were noted in patients with chest wall metastases with a mean LI of 15.9. In one patient with multiple discrete tumor foci, the larger foci had significantly decreased LI consistent with classic cytokinetic theory. The intralesional variation in LI was measured in 31 lesions. The average variation of LI/lesion was 1.2. Therefore, three samples should provide a representative LI. The interlesional LI was compared by taking multiple samples of two or three lesions per patient in seven patients. For each patient, there was little variation in mean LI from lesion to lesion. The data suggest that higher LI are associated with a poorer prognosis. Among patients with advanced T4 or metastatic disease, the median survivals for patients with LI less than 8 and greater than or equal to 8 were 79 weeks and 21 weeks, respectively. For patients with metastatic disease, the survivals were 56 and 9 weeks, respectively. The tumor growth fraction analyzed in one patient was 40%. In summary, the growth rate of this cancer in an individual patient is relatively homogeneous and LI may provide important prognostic information. Further studies are required to establish the value of LI in the staging and treatment of breast cancer.

Cell proliferation of colonic neoplasms in dimethylhydrazine-treated rats.

We have measured mitotic indices and 3H-thymidine-labelling indices for the colonic epithelial tumours induced in rats by the administration of dimethyl-hydrazine (DMH). The fraction-of-labelled-mitoses (FLM) technique has been used to estimate the duration of the cell-cycle phases. In general, mitotic and labelling indices in the tumours are similar to those in the proliferation zone of the normal crypt epithelium; lesions considered to be least well differentiated on histological grounds appear to have the lowest mean labelling index. Benign tumours and the different types of malignant tumours have mean cell-cycle times about half those of the normal mucosa.

The biological significance of atypical hyperplasia of the prostate.

In tissue biopsies and resection material (TUR) of the prostate a high coincidence (49.4%) was found between atypical primary hyperplasia with atypical-dysplastic microglandular, adenomatous and cribriform structures on the one hand and carcinomas on the other. The frequency of atypical hyperplasia in prostatic tissue without carcinoma was 2.8%. Microglandular pattern predominates in atypical hyperplasia combined with differentiated adenocarcinomas. A high coincidence between cribriformly structured glands of atypical primary hyperplasia and solid anaplastic-cribriform carcinomas can be observed. Autoradiographically the labeling index of atypical hyperplasia was three times as high as that of simple hyperplasia. The mean labeling index of atypical hyperplasia, however, was similar to that of poorly differentiated adenocarcinomas and cribriform carcinomas. The similar proliferation pattern of atypical hyperplasia and carcinomas as well as the high coincidence between both indicate that severe atypical primary hyperplasia is a precancerous lesion. Therefore, those patients with primary atypical hyperplasia with distinct cellular and structural atypia but without manifest carcinomas in prostatic biopsy or resection material should be followed up at short intervals.

Epithelial cell proliferation in the intestine of the winter flounder, Pseudopleuronectes americanus.

To study epithelial cell proliferation in the North American flounder (Pseudopleuronectes americanus), fed and fasted fish received intravenous injections of 3H-thymidine and were killed 1 1/2 to 2 h later. Radioautographs of proximal, middle, and distal intestinal segments revealed proliferating epithelial cells at all levels of intestinal folds including the crest although labelled nuclei were most abundant in the epithelial cells on the lower half of folds and between folds. Mature appearing goblet cells with labelled nuclei were observed at all levels of the folds. The mean labelling index was greater in the epithelium of fed than fasted flounder. In fed flounder the mean labelling index was greatest in the proximal segment and least in the distal segment; no substantive differences in mean labelling indices were observed in the various segments of intestine from fasted fish. Electron microscopy revealed no major structural differences among epithelial cells along the base of folds compared to cells near the crest of folds. These findings indicate that 1) epithelial cell proliferation occurs at all levels of the folds of flounder intestine and is not compartmentalized to the base of the folds and interfolds epithelium as reported in other teleosts, and 2) epithelial cell proliferation in the flounder intestine varies with feeding status.

Circadian periodicity of the cell kinetics of rat molar periodontal ligament

Circadian periodicity of DNA synthesis (S) phase and mitosis over a complete 12-hour light/12-hour dark cycle was studied in rat molar periodontal ligament (PDL) with 3H-thymidin autoradiography. Maximum percent labeled cells was at 10 a.m. in all regions, and mean labeling (24-hour average) was 1.44, 0.93, and 1.46 percent for the crest, midroot, and apical areas of the PDL, respectively. Maximum percent mitotic figures were also at 10 a.m. in all areas studied, and the mean number of mitoses averaged over 24 hours was 0.19, 0.12, and 0.14, respectively for crest, midroot, and apical areas. Ratios of mean labeling and mitotic indices were 7.58, 7.75, and 10.43 from crest to apex. Duration of mitosis and S phase were estimated at 1.2 and 9 hours, respectively. Analysis of data suggested that stress/strain within the PDL, associated with masticatory function, has a regional influence on duration of S phase, mitotic rate, and percentage of cells in the S phase. These results help define an in vivo experimental model for assessing the PDL cellular response to biomechanically defined force systems. Clinical implications are discussed.

Increased tritiated thymidine-labeling index of bone marrow myeloblasts following BCG administration in man

The in vitro (3H)thymidine-labeling index of bone marrow myeloblasts was determined in eight hematologically normal individuals before and after the administration of Bacillus Calmette-Guerin twice weekly for 2 weeks. The mean labeling indexes of myeloblasts were 30.5 and 45.2% respectively (P<0.004).

Human Malignant Lymphomas in Vitro

A series of 55 biopsies from different types of malignant lymphomas were characterized in short-term culture experiments and during prolonged growth in vitro. The majority of the lymphocytic lymphomas and half of the histiocytic lymphomas expressed surface immunoglobulin, either in monoclonal or polyclonal form, indicating B-lymphocyte derivation. No lysozyme production was noted in either type of lymphoma, giving further support to the notion that histiocytic lymphomas are not truly histiocytic. Production of beta2-microglobulin was higher in histiocytic than in lymphocytic lymphoma and Hodgkin's disease but did not significantly differ from the production observed in non-neoplastic lymph node disorders. Incorporation of 3H-thymidine varied greatly within each category of lymphoma; the highest mean labelling index was noted in histiocytic lymphoma, possibly reflecting the generally more malignant course in such cases. Epstein-Barr virus-associated nuclear antigen was observed in one case of Hodgkin's disease. Attempts to establish permanent tumor cell lines were successful only from two explants of lymphocytic lymphoma and one pleural effusion from histiocytic lymphoma. The two cell lines derived from lymphocytic lymphomas both exhibited B-lymphocyte characteristics. The histiocytic lymphoma line lacked lymphocyte markers, produced lysozyme and was found to be rich in cytoplasmic esterases. These features are consistent with a "true" histiocytic derivation of this line. Lymphoblastoid cell lines representing non-neoplastic EBV-carrying lymphocytes contaminating the biopsies were derived from 19 biopsies, with the highest frequency noted in cultures of biopsies from Hodgkin's disease. The tumor lines were all EBV-genome negative.

Migration pattern of splenic lymphocytes after local labelling of the pig spleen with 3H-cytidine.

In normal young pigs splenic lymphocytes were selectively labelled by injecting tritiated cytidine into a splenic artery. 10 h later several lymphoid and non-lymphoid organs were investigated for spleen-derived lymphocytes by autoradiography. The relative and absolute organ distribution of the labelled cells was determined. Labelled lymphocytes appeared rapidly in the peripheral blood reaching a mean labelling index of 4.8%. More splenic lymphocytes were found in thymus dependent areas than in thymus independent areas of lymphoid organs. Nearly 40% of all emigrated lymphocytes homed to lymph nodes and only about 1% in the thymus. A surprisingly high number of splenic lymphocytes were located in the bone marrow and the lung.