Fraction of human bone marrow (BM) cells in DNA synthesis has been studied by sampling BM from the sternum or the iliac crests every 4 hours during one 24-hour period in 16 healthy male volunteers. Three of the subjects underwent the sampling procedure twice, resulting in 19 24- hour profiles. The percentage of cells in DNA synthesis measured by flow cytometry demonstrated a large variation along the circadian time scale for each 24-hour profile, with a range of variation from 29% to 339% from lowest to highest value. Seventeen profiles (89.5%) had the highest DNA synthesis during waking hours between 08:00 hours and 20:00 hours, and the lowest percentage of cells in DNA synthesis between 00:00 hours and 04:00 hours. The mean value of the lowest DNA synthesis for each 19 24-hour period was 8.7% +/- 0.6%, while the mean value of the highest DNA synthesis was 17.6% +/- 0.6%, ie, a twofold difference. There was no difference in DNA synthesis between winter and summer. A significantly higher DNA synthesis was demonstrated for samples obtained from sternum as compared with the iliac crests, but the same circadian pattern was demonstrated for both localizations. By taking circadian stage-dependent variations in DNA synthesis into account it may be possible to reduce BM sensitivity to cytotoxic chemotherapy, to increase the effect of hematopoietic growth factors as well as increase the fraction of proliferating cells with careful selection of time of day for harvesting BM cells for auto- or allografting.
Biopsy material from 17 human non-small-cell lung carcinomas (NSCLC) was maintained in agar overlay culture as tumour fragment spheroids for 40 days. A practical procedure for the formation of spheroids and organ culture is described. The mechanically dissociated tumour specimens showed a variation in their ability to generate spheroids that was not related to the ploidy or the histological differentiation of the biopsies. Light microscopic observations revealed a heterogeneous spheroid population with a mixture of tumour cells and stromal elements. Most of the histological elements normally found in human NSCLC could be seen in the spheroids. The cellular components in the spheroids varied between highly cellular to sparsely cellular, dominated by stromal elements. The squamous carcinomas were in general found to generate highly cellular spheroids more often than the adenocarcinomas. Spheroids with a different cellular content could be selected in vitro by using a morphometric technique. Diameter measurements showed a large variability in spheroid growth. Most of the spheroids decreased in size although bromodeoxyuridine labelling indicated active cell proliferation in the specimens. Frequent changes of medium did not affect spheroid growth. The culture system presented provides a model for studying the cellular heterogeneity as well as the biological characteristics of tumour tissue from individual patients in vitro.
Variations in cell yield and proliferative activity of human bone marrow (BM) progenitor cells were determined with flow cytometry along the 24‐h (circadian) time scale. Equal volumes of BM were aspirated every 5 h, altogether 5 times in 5 healthy men. An average 6‐fold higher yield of positive selected CD34+ cells occurred in each subject when BM was aspirated during the daytime and late afternoon, while a lower yield occurred during the night. Using all CD34+ cell yield data normalized to percentage of mean, a significant time–effect was found by ANOVA (p=0.02) and a significant circadian rhythm was detected by the least‐squares fit of a 24 h cosine (p=0.02). The 95% confidence limits of the acrophase (time of highest values) were computed to be at midday between 10:24 and 14:48 h. A highly significant correlation (p=0.001) was found between proliferation of positive selected CD34+ cells and the more mature myeloid precursor cells from the same BM aspirates, suggesting a common temporal pattern along the circadian time scale. However, no correlation was demonstrated between proliferation and cell yield of CD34+ selected cells, suggesting that mechanisms other than variation in proliferation may cause the circadian rhythm in stem cell yield. These circadian variations in stem cell yield and proliferation suggest that proper timing within 24 h may potentially be important regarding outcome from progenitor cell harvesting and treatment with haematopoietic growth factors.
Primary malignant neoplasms of the nervous system differ from other types of malignancy in several ways. Clinical progression is due to local invasive growth, while metastases outside the skull are rare. The tumors show no sharp delimitation from the surrounding normal tissue. At the edge, an ill-defined area of invasive tumor cells, reacting glial cells and inflammatory cells is present. At the same time the primary brain tumors are biologically heterogeneous. In this review, a short survey of markers for malignancy in primary brain tumors is given, and some properties of importance for invasive behavior, are listed. These include different cellular enzymes, phagocytotic property, locomotive and proliferative characteristics. Studies of primary brain tumors in situ show invasive growth into the surrounding brain tissue, often followed by hemorrhage and necrosis. In addition spread of tumor cells takes place along preexisting intracranial structures. Recently, several systems for the study of brain tumor invasiveness in culture have been elaborated. Both experimental and human gliomas have been tested. The target tissues include organ culture of embryonic chick heart muscle, chorioallantoic membrane, fetal rat brain tissue and reconstructed vessel walls. It has been shown that glioma cells are able to split junctions between normal cells. They destroy and phagocytose the normal cells and penetrate the normal tissue. The use of brain tissue and reaggregated brain cell cultures as target for glioma cells in culture opens the possibility for an elucidation of invasiveness as one of the most important properties of malignancy in the nervous system.
Bone marrow samples from sternum and iliac crests were harvested every 4 hours during 19 24-hour periods from 16 healthy male volunteers, and myeloid progenitor cells were cultured by the colony-forming unit- granulocyte-macrophage (CFU-GM) assay. A large interindividual variation was observed in the mean number of colonies during each 24- hour period, with the highest 24-hour mean colony number being about 600% greater than the lowest (range: 16 +/- 2.3 to 100.3 +/- 4.5). For each individual the difference between the lowest and highest colony number throughout the day ranged from 47.4% to 256.3% of the mean colony number of each series. A circadian stage-dependent variation in the number of colony-forming units of myeloid progenitor cells (CFU-GM) of human bone marrow was demonstrated, with values 150% higher, on the average, during the day as compared with the night. The overall data (891 CFU-GM replicates) exhibited a significant 24-hour rhythm (P less than .001) with an acrophase at midday (12.09 hours with 95% confidence limits from 10.32 to 13.49 hours) and a trough at midnight. This 24- hour variation was found to covary with DNA synthesis in the total proliferating bone marrow cell population. A seasonal effect on CFU-GM numbers was detected by ANOVA (P = .014) and by the least squares fit of a 1-year cosine (P = .015), with the highest number found in summer. The potential relevance of these findings should be examined in relation to cytotoxic cancer therapy, use of hematopoietic growth factors, and bone marrow transplantation.
Enzyme activities and the protein to DNA ratio in gastric biopsy specimens from patients with gastric cancer and polyps have been measured and compared with values from controls. In uninvolved mucosa in antral gastric cancer increased activities were found for several membrane and lysosomal enzymes, whereas the monoamine oxidase (MAO) activity was decreased (p less than 0.0005). In cancer tissue the MAO was also decreased (p less than 0.0003). In uninvolved mucosa in gastric cancer of the body, most membrane and lysosomal enzyme activities were increased. In the cancer tissue itself an increase in membrane enzyme activities was found for several enzymes, whereas the MAO activity was decreased (p less than 0.0001). Differences between activities in specimens from the gastric mucosa in patients with gastric polyps and those in controls were less pronounced than between gastric cancer and controls. A discriminant analysis, using the enzymes most sensitive to establish correct diagnosis, could identify normal gastric mucosa in 85-95%, atrophic gastritis in 56-63%, and uninvolved mucosa in gastric cancer in 66-78%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.