Pancreatic growth after partial resection of normal and enlarged pancreas in rats fed soya flour

1988 ◽  
Vol 255 (5) ◽  
pp. G670-G675
Author(s):  
P. S. Oates ◽  
R. G. Morgan
Keyword(s):  
Dna Content ◽  
Cell Loss ◽  
Partial Resection ◽  
Limited Capacity ◽  
Soya Flour ◽  
Cell Turnover ◽  
Normal Pancreas ◽  
Nonparenchymal Cells ◽  
Pancreatic Growth ◽  
Total Dna

Pancreatic growth was studied after partial resection of the normal-sized pancreas in rats fed heated soya flour (HSF) or the enlarged gland in rats fed raw soya flour (RSF). Resection involved the removal of the splenic and gastric segments and in both the normal and enlarged gland this represents a loss of approximately 55% of total pancreatic mass. After partial resection animals were either continued on these preresected diets or changed to the alternative diets. For at least the first 8 days after resection, in all conditions studied, there was a significant increase in DNA synthesis in the pancreas, involving both parenchymal and nonparenchymal cells as shown by autoradiography. The increased cell turnover was not associated with any increase in total DNA content of the gland, indicating that the increase paralleled cell loss in response to injury caused by the surgery. By 160 days after resection of the normal pancreas, RSF feeding caused both hypertrophy and hyperplasia of the remnant, but after partial resection of the enlarged gland, growth was limited to hypertrophy. These results suggest that the pancreas has a limited capacity for additional growth after that initially caused by RSF.

scholarly journals CCK-independent mTORC1 activation during dietary protein-induced exocrine pancreas growth

2010 ◽  
Vol 299 (5) ◽  
pp. G1154-G1163 ◽  
Author(s):  
Stephen J. Crozier ◽  
M. Dolors Sans ◽  
Jackie Y. Wang ◽  
Stephen I. Lentz ◽  
Stephen A. Ernst ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Dna Content ◽  
Dietary Protein ◽  
Exocrine Pancreas ◽  
Mammalian Target Of Rapamycin ◽  
High Protein ◽  
Pancreatic Growth ◽  
Total Dna ◽  
Mtorc1 Activation ◽  
Cck Release

Dietary protein can stimulate pancreatic growth in the absence of CCK release, but there is little data on the regulation of CCK-independent growth. To identify mechanisms whereby protein stimulates pancreatic growth in the absence of CCK release, C57BL/6 control and CCK-null male mice were fed normal-protein (14% casein) or high-protein (75% casein) chow for 7 days. The weight of the pancreas increased by 32% in C57BL/6 mice and 26% in CCK-null mice fed high-protein chow. Changes in pancreatic weight in control mice were due to both cell hypertrophy and hyperplasia since there was an increase in protein-to-DNA ratio, total DNA content, and DNA synthesis. In CCK-null mice pancreatic growth was almost entirely due to hypertrophy with both protein-to-DNA ratio and cell size increasing without significant increases in DNA content or DNA synthesis. ERK, calcineurin, and mammalian target of rapamycin complex 1 (mTORC1) are activated in models of CCK-induced growth, but there were no differences in ERK or calcineurin activation between fasted and fed CCK-null mice. In contrast, mTORC1 activation was increased after feeding and the duration of activation was prolonged in mice fed high-protein chow compared with normal-protein chow. Changes in pancreatic weight and RNA content were completely inhibited, and changes in protein content were partially abated, when the mTORC1 inhibitor rapamycin was administered during high-protein chow feeding. Prolonged mTORC1 activation is thus required for dietary protein-induced pancreatic growth in the absence of CCK.

The role of the cytoskeleton in mechanotransduction in human osteoblastlike cells

2003 ◽  
Vol 22 (5) ◽  
pp. 271-274 ◽  
Author(s):  
Nahum Rosenberg
Keyword(s):  
Metabolic Activity ◽  
Mechanical Stimulation ◽  
Dna Content ◽  
Cellular Mechanisms ◽  
Unique Role ◽  
Key Factor ◽  
Total Dna ◽  
Static Conditions ◽  
Expected Increase

The regulation of osteoblast proliferation is a key factor in maintaining bone mass. The enhancement of this process can be achieved by stimulating the proliferation of these cells. Mechanical stimulation is one of the important enhancing factors, but the exact cellular mechanisms of mechanical stimulation, i.e., mechanotransduction, are unknown. In order to investigate the role of the cytoskeleton components in mechanotransduction for cell proliferation, I compared the total DNA content in cultured replicates of osteoblast-like cells derived from three human donors following their exposure to enhancing mechanical stimulation, with and without added specific microtubular and microfilament polymerization blockers (Colchicin and Cytochalasin D, respectively). The results revealed the essential and unique role of the microtubular component of the cytoskeleton in mechanotransduction for proliferation by showing that Colchicin blocked the expected increase in the DNA content after mechanical stimulation of the cultured replicates without altering the total DNA content in replicates at static conditions. Conversely, a specific blockage of the microfilament polymerization presented uniform cytotoxic effect in both static and biomechanically active environments. Since previous reports indicated the essential role of microfilament polymerization for the osteoblast metabolic activity, the results of this study further support the hypothesis that the mechanotransduction mechanisms for proliferation and metabolic activity are mediated by different intracellular pathways.

Short-term effects of feeding raw soya flour on pancreatic cell turnover in the rat

1984 ◽  
Vol 247 (6) ◽  
pp. G667-G673
Author(s):  
P. S. Oates ◽  
R. G. Morgan
Keyword(s):  
Dna Synthesis ◽  
Cell Damage ◽  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Soya Flour ◽  
Cell Turnover ◽  
Tissue Necrosis ◽  
Short Term ◽  
Pancreatic Cell ◽  
Duct Cells

Pancreatic acinar cell turnover was studied after a 48-h fast and in rats fed raw soya flour (RSF) for up to 28 days. Feeding RSF for 2 days resulted in a significant increase in pancreatic weight and RNA content while protein was increased by the 4th day compared with rats fasted for 48 h. RSF also resulted in a significant increase in RNA by the 4th day and weight and protein by the 7th day compared with rats fed heated soya flour (HSF). This pancreatic hypertrophy was maintained for the rest of the study period. Two days after starting RSF, pancreatic DNA synthesis, measured bythe rate of incorporation of [3H]thymidine into pancreatic DNA, had increased sixfold compared with that in animals fedHSF but returned to control values again by the 4th day on the diet. Autoradiography showed that this increase in DNA synthesis occurred in both acinar and duct cells, with turnover in acinar cells preceding that in duct cells. A second moregradual rise in DNA synthesis was seen from the 7th to 28th day. This peak in DNA synthesis was associated with an increased total pancreatic DNA content and occurred predominately in duct cells with a smaller contribution from acinar cells. Histological studies of the pancreas during the 1st wk showed cell damage and tissue necrosis, possibly due to exposure to high levels of cholecystokinin released by RSF. The first peak in DNA synthesis may be a regenerative response to this damage. The second more delayed peak appears to be hyperplasia in response to a trophic stimulus, again possibly mediated by cholecystokinin.

The mechanism of action of griseofulvin

1968 ◽  
Vol 14 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Floyd M. Huber ◽  
David Gottlieb
Keyword(s):  
Cell Wall ◽  
Botrytis Cinerea ◽  
Aspartic Acid ◽  
Mechanism Of Action ◽  
Dna Content ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Lipid Fraction ◽  
Acid Incorporation ◽  
Total Dna

Griseofulvin had no effect on the respiration of Botrytis cinerea but, nevertheless, inhibited growth and caused abnormal hyphal formations, including stunting, spiraling, thickening of the cell wall, and disorientation of growth. Treated cells had an increase in total deoxyribonucleic acid and phosphorus but not in protein, carbohydrate, lipid, and ribonucleic acid. Griseofulvin-treated cells synthesized DNA from labelled glucose and glycine continuously and for much longer periods than control cells so that their total DNA content was greater than that in untreated cells. However, the antibiotic allowed slightly less incorporation with aspartic acid -U-14C as the precursor than the controls. Griseofulvin caused 25 to 50% increased incorporation of carbon into RNA from glucose and glycine but the increases were not due to a prolongation of the synthetic period, and again aspartic acid incorporation was slightly decreased. Griseofulvin was bound to the particulate parts of the cell and was especially high in the lipid fraction of the cell. The antibiotic was not bound to DNA or to RNA.

The Influence of Protected Passive Mobilization on the Healing of Flexor Tendons: A Biochemical and Microangiography Study

HAND ◽  
1981 ◽  
Vol os-13 (2) ◽  
pp. 120-128 ◽  
Author(s):  
R. H. Gelberman ◽  
D. Amifl ◽  
M Gonsalves ◽  
S. Woo ◽  
W. H. Akeson
Keyword(s):  
Dna Content ◽  
Tendon Sheath ◽  
Steady Increase ◽  
Normal Pattern ◽  
Flexor Tendons ◽  
Healing Tendon ◽  
Total Dna ◽  
Passive Mobilization ◽  
And Control ◽  
Stimulation Of

The purpose of this investigation was to determine the effects of protected passive mobilization on the repair processes of healing flexor tendons. The total DNA content of the healing tendon and tendon sheath was correlated with their vascularity over a twelve week period. A gradually increasing range of passive motion between the 21st and 84th days after operation was associated with reorientation of the blood vessels to a more normal pattern, a steady increase in sheath and repair site cellularity compared with the immobilized and control tendons. The altered vascularity reflected a stimulation of tendon scar remodeling, and the increased DNA signified an acceleration in tendon maturation.

scholarly journals Flow cytometric measurement of total DNA content and incorporated bromodeoxyuridine.

1983 ◽  
Vol 80 (18) ◽  
pp. 5573-5577 ◽  
Author(s):  
F. Dolbeare ◽  
H. Gratzner ◽  
M. G. Pallavicini ◽  
J. W. Gray
Keyword(s):  
Dna Content ◽  
Flow Cytometric ◽  
Flow Cytometric Measurement ◽  
Total Dna

scholarly journals Urokinase and the intestinal mucosa: evidence for a role in epithelial cell turnover

Gut ◽  
1998 ◽  
Vol 43 (5) ◽  
pp. 656-663 ◽  
Author(s):  
P R Gibson ◽  
I Birchall ◽  
O Rosella ◽  
V Albert ◽  
C F Finch ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Intestinal Mucosa ◽  
Cell Loss ◽  
Distal Colon ◽  
Median Number ◽  
Column Height ◽  
Intestinal Epithelial ◽  
Cell Turnover ◽  
Intestinal Epithelia

Background—The functions of urokinase in intestinal epithelia are unknown.Aims—To determine the relation of urokinase expressed by intestinal epithelial cells to their position in the crypt-villus/surface axis and of mucosal urokinase activity to epithelial proliferative kinetics in the distal colon.Methods—Urokinase expression was examined immunohistochemically in human intestinal mucosa. Urokinase activity was measured colorimetrically in epithelial cells isolated sequentially from the crypt-villus axis of the rat small intestine. In separate experiments, urokinase activity and epithelial kinetics (measured stathmokinetically) were measured in homogenates of distal colonic mucosa of 14 groups of eight rats fed diets known to alter epithelial turnover.Results—From the crypt base, an ascending gradient of expression and activity of urokinase was associated with the epithelial cells. Median mucosal urokinase activities in each of the dietary groups of rats correlated positively with autologous median number of metaphase arrests per crypt (r=0.68; p<0.005) and per 100 crypt cells (r=0.75; p<0.001), but not with crypt column height.Conclusions—Localisation of an enzyme capable of leading to digestion of cell substratum in the region where cells are loosely attached to their basement membrane, and the association of its activity with indexes of cell turnover, suggest a role for urokinase in facilitating epithelial cell loss in the intestine.

Fluorometric determination of the total DNA content of different yeast species using 4′, 6-diamidino-2-phenyl-indol-dihydrochloride

1985 ◽  
Vol 31 (12) ◽  
pp. 1164-1166 ◽  
Author(s):  
H. G. Leusch ◽  
M. Hoffmann ◽  
C. C. Emeis
Keyword(s):  
Dna Content ◽  
Yeast Species ◽  
Yeast Cells ◽  
Fluorometric Determination ◽  
Enzymatic Pretreatment ◽  
Cell Lysate ◽  
Highly Sensitive ◽  
Total Dna ◽  
Sensitive Method

A highly sensitive method has been developed to measure quantitatively the DNA content of yeast cells. The reaction between the fluorescent dye 4′, 6-diamidino-2-phenyl-indol-dihydrochloride and DNA in a crude lysate from protoplasts can be measured without prior extraction of the DNA. Interferences by the high protein and RNA content of yeast cells, which often limit the accuracy of common methods employed in the determination of DNA content, were eliminated by suitable enzymatic pretreatment of the cell lysate.

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