Metabolism of histones in malignant tissues and liver of the rat and mouse

1. The relative amounts of incorporation in vivo of l-lysine, and in one experiment l-arginine, into different histone fractions from Krebs ascites and a lymphoma ascites cells of mice and a `solid' tumour and liver of rats have been determined. 2. No marked differences in the incorporations of the amino acids into the fractions F1, F2a, F2b and F3 from the tumours were generally observed, although in some experiments there was a greater incorporation into fraction F2b, which could be decreased by further purification. 3. In the tumours the incorporations into all cell protein fractions obtained were approximately the same, indicating that the amount of incorporation was that required for the increase of cell mass. 4. In rat liver, the incorporations into fractions F1, F2a and F3 were not greatly different. That into fraction F2b was variable. The incorporation into the histone fractions was much less than that into the acid-insoluble nuclear residue, indicating that considerable turnover of amino acids in the latter occurs. 5. The decrease in radioactivity of labelled histone and acid-insoluble nuclear protein in vivo during several days confirmed the relatively small turnover of the histone fraction. The time taken for liver whole histone to lose half its radioactivity was about 1 week. A histone fraction of slower metabolism was also detected. 6. It is concluded that no appreciable turnover of protein occurs in any one histone fraction, the somewhat higher values obtained in certain cases being associated with acidic impurities. The apparently high rate of incorporation into histone of resting liver is discussed in relation to recent evidence on DNA metabolism of resting liver.     

Comparison of serum free thyroxine measurements by chemiluminescence and equilibrium dialysis

A study of 239 patients compared free thyroxine (FT4) measurements made by equilibrium dialysis (ED) with measurements made using the Magic Lite FT4 chemiluminescence (Cl) immunoassay (Ciba Corning Immunodiagnostics). Patient groups: 41 normals; 27 hyperthyroid; 29 hypothyroid; 37 sick euthyroid; 10 chronic renal failure (CRF) and 25 pregnant patients; 13 oestrogen; 10 heparin; 12 salicylate; and 9 dilantin-treated patients; 3 lipaemic; 5 haemolysed; 6 hyperbilirubinaemic patients; 6 low thyroid binding protein (TBP) and 6 high TBP level patients. The two assays gave comparable results in most groups. Both assays tended to give elevated values in heparinized patients but FT4–ED results were more obviously affected. Pregnant patients and women on oral oestrogen had higher mean values with FT4–ED. In both assays the sick euthyroid and CRF patients had mean FT4 values similar to healthy euthyroid patients; the range of values in sick euthyroid and CRF patients was similar in both assays but wider than in healthy euthyroid patients. A supplemental study of 81 unselected acutely ill patients using FT4–Cl alone confirmed the wider range of values to be anticipated in sick euthyroid patients.     

Step response of lung surface-to-volume ratio by light-scattering stereology

By means of backscattered light from a pointlike source on the pleural surface, we investigated the dynamic behavior of the surface-to-volume ratio (S/V) in excised dog lobes subjected to small volume steps both in and out on both the inflation and deflation limb of standard pressure-volume maneuvers. The technique utilizes the established correlation of the pattern of backscattered light with morphometric mean linear intercept and is suitable for dynamic studies. We hypothesized that 1) there would be a difference in the timing of stress relaxation or recovery between alveolar septa and the fibromuscular tissue in the alveolar duct that would reveal itself as a temporally changing S/V after a step-volume change and 2) that geometric hysteresis (looping of S/V with volume), as seen with large volume excursion histories, would be similarly present in small tidal volume loops. Our experimental results contradicted both hypotheses. In particular, we found virtually no change in S/V after a step-volume change, even in the presence of substantial stress adaptation. In addition, when geometric hysteresis of small loops was present, it was always in the sense opposite to the geometric hysteresis of large loops. We conclude that 1) there is a functional "matching" of the stress-adaptive timing between alveolar septa and ductal mouths and 2) during small volume looping, the stress hysteresis (looping of stress with volume) in the ductal tissue may be larger than that of the septa, including surface tension.     

Use of piezoelectric shock waves to effect release of amylase from capsules containing the amylase producing rat pancreatic tumour cell line AR42J

Summary The amylase-producing rat pancreatic tumour cell line AR42J was encapsulated in alginate/poly-L-lysine under conditions where the secreted amylase was retained within the system. On treatment with shock waves from a lithotriptor, the porosity of the capsules was changed and the amylase was released from the system. Conditions of treatment were manipulated in order to maximise release of the amylase without significantly reducing the cell viability.     

Plant regeneration from embryogenic callus initiated from immature inflorescences of several high-tannin sorghums

A procedure was established for the induction of regenerable calli from immature inflorescence segments of high-tannin cultivars of sorghum (Sorghum bicolor (L.) Moench). Murashige & Skoog's medium with several components altered was utilized for inducing, maintaining, and regenerating the cultures. Embryogenic calli formed at a frequency of 8–70% depending on the genotype. During a ten-month period, 3600 plants were regenerated from eight genotypes tested. Among the developmental stages of immature inflorescence tested (from differentiation of secondary branch primordia to floret formation) no critical differences were found in potential for callusing, embryogenesis or regeneration. Genotypic differences were observed in pigment production, embryogenic callus formation, shoot differentiation, and in maintenance of regeneration capacity.Abbreviations 2,4-D dichlorophenoxyacetic acid This is Journal Paper Number 11972 from the Purdue University Agricultural Experiment Station     

Pentose phosphate pathway in rat colonic epithelium

The colonic cells of the large intestine are one of the most proliferative tissues of the animal body. The pentose pathway has an essential role in cell division and growth being the only pathway forming ribose 5-P necessary for all nucleotide and nucleic acid sunthesis. The pentose pathway may also provide reducing potential as NADPH for biosynthesis and C-3- C-8 glycolyl compounds. The maximum catalytic capacities of the reactions of the non-oxidative pentose pathway for the conversion of ribose 5-P to hexose and triose phosphates by the proximal and distal colon under feeding and starvation regimes are among the highest in the animal body. The qualitative presence of the oxidative pentose pathway was assessed by measurement of the C-1/C-6 ratio value of 1.67-1.82. Enzymes of the F-type and L-type pentose pathways are present in colonocytes and their maximum catalytic activities in colonocyte cytosol are reported. The contribution of the F-type pentose cycle to the total glucose metabolism of colonocytes, measured by the specific yield method, is negligibly low (approximately 1.5%). Colonic epithelial cells use glucose at a high rate (7.1 +/- 0.33 mumol min-1g-1 dry wt) and 79% of the glucose is converted to lactate. Arabinose 5-P has an intermediary role in the formation of keto pentose, sedoheptulose and hexose phosphates from ribose 5-P by colonocyte cytosol. The intermediary and reaction products of [1-13C] ribose 5-P dissimilation by colonocytes is investigated by 13C NMR spectroscopy. The 13C positional isotope distributions show labelling of C-1 and C-3 of hexose 6-phosphates consistent with either the theoretical predictions of the F-type pentose pathway or of the activities of exchange reactions catalysed by transketolase and/or transaldolase. Measurements of exchange reactions showed that the C-1/C-3 labelling of these compounds is mostly, if not wholly, attributable to exchange catalysis by these group transferring enzymes. The results suggest that the F-type PC has little role in the glucose metabolism of colonocytes and pentose phosphate formation may thus occur by a contribution (approx 20% of the total glucose metabolism) by the alternate L-type pathway.     

Effect of immune system imagery on secretory IgA

This study was an investigation of the effects of physiologically-oriented mental imagery on immune functioning. College students with normal medical histories were randomly selected to one of three groups. Subjects in Group 1 participated in short educational training on the production of secretory immunoglobulin A. They were then tested on salivary IgA, skin temperature, and the Profile of Mood States (POMS) before and after listening to a 17-minute tape of imagery instructions with specially composed background entrainment music designed to enhance imagery. Subjects in Group 2 (placebo controls) listened to the same music but received nor formal training on the immune system. Group 3 acted as a control and subjects were tested before and after 17 minutes of no activity. Treatment groups listened to their tapes at home on a bi-daily basis for six weeks All groups were again tested at Weeks 3 and 6. Secretory IgA was analyzed using standard radial immunodiffusion techniques. Repeated measures analyses of variance with planned orthogonal contrasts were used to evaluate the data. Significant overall increases (p<0.05) were found between pre- and posttests for all three trials. Groups 1 and 2 combined (treatment groups) yielded significantly greater increases in sIgA over Group 3 (control) for all three trials. Group 1 (imagery) was significantly higher than Group 2 (music) in antibody production for Trials 2 and 3. Symptomatology, recorded by subjects at Weeks 3 and 6, was significantly lower for three symptoms (rapid heartbeat, breathing difficulty, and jaw clenching), favoring both treatment groups over the control group.     

The crystal violet nuclei staining technique leads to anomalous results in monitoring mammalian cell cultures

Nuclear counts determined by crystal violet staining from samples of stationary or microcarrier cultures of hybridomas, CHO or Vero cells were consistently and significantly higher than cell concentrations determined by the trypan blue or Coulter counter methods. This difference was attributed to the presence of a significant proportion of binucleated cells, which are assumed to be 35% of the cell population in the stationary phase of Vero cultures. The proportion of such cells during exponential growth was variable. However, continuous sub-culture of these cells induced a degree of synchrony during growth which resulted in a cyclic variation of the difference between the cell and nuclei counting techniques. This data indicates that care should be taken in interpreting cell culture profiles based solely on crystal violet nuclei staining counts.