Cell proliferation kinetics of normal and tumour tissue in vitro: quiescent reproductive cells and the cycling reproductive fraction.

Current methods for measuring the cell kinetics of human tumours are made and interpreted within the context of a simplistic two compartment model for cell proliferation, consisting of cells that are cycling and those that are not. It is now recognized that the non-cycling compartment of many tumours is heterogeneous, composed of non-reproductive end-stage cells and reproductive cells that are dormant/quiescent. We have developed an in vitro analysis that distinguishes for the first time quiescent reproductive cells from non-reproductive end-stage cells and have integrated this analysis with monolayer clonogenic and suicide assays to simultaneously quantitate the duration of the cell cycle and reproductive cells that are: cycling, quiescent, clonogenic, and non-reproductive end-stage cells. We have defined a new parameter, the Cycling Reproductive Fraction (CRF), which is the cycling cell population referenced specifically to the reproductive cell population. Measurements of CRF from 72 tumour biopsies and from 5 normal foreskins showed that CRF approached 100% in some tumours; however, CRF showed near normal values (< 1%) in others suggesting that cell cycle control may be maintained in some tumours. Because of CRF's improved specificity, we believe that CRF may enhance classification, prognostication, and the optimization and prediction of response to chemotherapy.

Changes in sulphate retention, soil chemistry and drainage water quality along an upland soil transect.

Soils sampled along an altitudinal transect in an upland area of North East Scotland have been used to investigate downslope changes in the capacity of soils to retain sulphate. Simulated laboratory experiments involving the leaching of reconstituted cores with 'rainfall' containing low (1.85 mg litre(-1) and high (51.90 mg litre(-1) concentrations of sulphate indicate that soils developed on upper slopes have a limited capacity to adsorb sulphate, whereas soils on lower slopes have a much greater sulphate adsorption capacity. Soil drainage water, produced from 'sensitive' upper slope soils may therefore be significantly modified by physico-chemical reactions in lower slopes before reaching watercourses.

Assessment by laboratory simulation of approaches to amelioration of peat acidification.

The effects of different liming materials (CaCO(3), Ca(OH)(2), CaHPO(4), and dolomite) on soil and drainage-water chemistry have been investigated for upland acidic peats by using a soil-core-simulation experiment. Intact cores from three depths (0-30, 0-60, and 0-90 mm) were subjected to ten years of simulated rainfall. Drainage water was periodically analysed for Ca(2+), Mg(2+), Na(+), K(+) NH(4)(+), TOC, Cl(-), SO(4)(2-), NO(3)(-), PO(4)(3-), and pH, and at the end of the experiment the cores were destructively sampled and analysed. Temporal changes in soil and drainage-water chemistry are used to evaluate the advantages and disadvantages of using different liming materials for the amelioration of soil and drainage-water chemistry.

The density of clonogenic cells in human solid tumors.

Considering that tumors are maintained by clonogenic cells, and that the primary target in the therapy of cancer is the clonogenic cell, the density of clonogens in a tumor could become an important parameter in quantitating the response to therapy. Indirect methods for determining the density of clonogenic cells in human tumors based on the response of tumors to radiation suggest there are circa 1 X 10(5) clonogens per gram with a large range. Direct methods, based on the measurement of cloning efficiency of enzymatically disaggregated biopsies of human tumors in soft agar, suggest a clonogen density of approximately 1,500 clonogens per gram. As this value is inconsistent with the prior data, we chose to determine the density of clonogenic cells in human tumors by assaying the enzyme digest of biopsies of human tumors for clonogenic cells using an enriched monolayer clonogenic assay. We determined the average clonogen density to be 1.12 x 10(5) clonogens per gram with a large range. The agreement with the indirect method suggests that the enriched monolayer clonogenic assay supports the proliferation of the cell population responsible for maintaining the tumor.

Demonstration of antibodies to denatured type I and type II collagen in juvenile rheumatoid arthritis, Still's syndrome and controls by [14C] collagen radioimmunoassay.

From 88 sera of patients with juvenile rheumatoid arthritis 30.6% showed antibodies to denatured type I collagen an 31.8% antibodies to type II collagen, a percentage which corresponds to radioimmunoassay results in adult RA. Rheumatoid factors were demonstrated with Waaler-Rose test in 14.7% and with latex test in 6.8% of investigated patients. Results of investigations with collagen types I and II correlated in 73.7%. Whilst type I collagen antibodies were found with equal frequency in active and non-active stages, type II antibodies were twice as frequent in active stages as in non-active stages. Sixteen sera of children with non-rheumatoid diseases had no collagen antibodies. JRA sera and controls differed with statistical significance in regard to collagen antibodies. 36 sera of children with Still's syndrome showed antibodies to type I collagen in 13.8% and antibodies to type II collagen in 33.3%. Both types of antibodies appeared more frequently in clinically active stages. The sera differed from controls with statistical significance in regard to collagen antibodies.

Studies on the primary and secondary structure of potato spindle tuber viroid: products of digestion with ribonuclease A and ribonuclease T1, and modification with bisulfite.

Potato spindle tuber viroid (PSTV), a small infectios RNA, has been completely digested with RNase T1 and RNase A, and the resulting oligonucleotides have been sequenced using 5'-terminal 32p-labelling with gamma-32p ATP and T4 polynucleotide kinase, fingerprinting and controlled nuclease P1 digestion. Modified nucleotides have not been detected in 5'-positions of these oligonucleotides. PSTV consists of about 359 nucleotides and contains a remarkable stretch of 18 purines, mainly adenosines; there is no AUG initiation triplet present. The established oligonucleotide sequences preclude a perfect intramolecular base complementarity within the covalently closed viroid circle. Therefore, the rigid, rod-like native secondary structure of PSTV, as seen in the electron microscope, must be based on a defective rather than on a homogeneous RNA helix. The detailed analysis of the bisulfite-catalized modification of cytidine to uridine in PSTV revealed a higher reactivity for the majority of the cytidines than would be expected for a perfect helix. Since only cytidines in single-stranded regions are knonw to be fully reactive, this finding provides additional evidence for defects in the helical secondary structure of PSTV.

Colchicine-induced inhibition of lipoprotein and protein secretion into the serum and lack of interference with secretion of biliary phospholipids and cholesterol by rat liver in vivo.

Rats were injected with colchicine and the secretion of triglycerides into the serum was studied for 90 min after injection of [(14)C]palmitic acid and Triton WR 1339. The release of labeled and chemically determined triglyceride was reduced to about 20-30% of control values. The effect of colchicine on serum triglyceride levels was not dependent on the presence of Triton and was similar in males and females and in fed and fasted rats. The effect was dose dependent and was reversible 6-7 h after injection of 0.05 mg/100 g body weight. Colchicine inhibited also the release of labeled proteins into the serum but did not affect the amount of [(3)H]leucine incorporated into liver proteins. Within 4 h of colchicine treatment there was an 80% fall in serum very low density lipoproteins (VLDL), a 30% fall in serum high density lipoproteins (HDL), and no change in the d > 1.21 protein level, but reduction in the appearance of labeled proteins was encountered in all serum fractions. Colchicine had no effect on the rate of bile flow and on the secretion of phospholipids and cholesterol into the bile. In the hepatocyte there was accumulation of Golgi-derived secretory vesicles, containing nascent VLDL particles; these vesicles were seen also in the vicinity of the sinusoidal cell surface, but the space of Disse contained few or no VLDL particles. There was an apparent reduction in microtubules and some increase in microfilaments. It is suggested that microtubules affect the secretion of lipoproteins and proteins into the serum by maintaining the organization of the plasma membrane required for its fusion with secretory vesicles. The lack of effect of colchicine on biliary lipid secretion indicates that the latter is not dependent on vesicular transport.