Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Carrying Capacity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources
PubMed2003

Ku80 plays a role in non-homologous recombination but is not required for T-DNA integration in Arabidopsis.

Chromosomal breaks are repaired by homologous recombination (HR) or non-homologous end joining (NHEJ) mechanisms. The Ku70/Ku80 heterodimer binds DNA ends and plays roles in NHEJ and telomere maintenance in organisms ranging from yeast to humans. We have previously identified a ku80 mutant of the model plant Arabidopsis thaliana and shown the role of Ku80 in telomere homeostasis in plant cells. We show here that this mutant is hypersensitive to the DNA-damaging agent methyl methane sulphonate and has a reduced capacity to carry out NHEJ recombination. To understand the interplay between HR and NHEJ in plants, we measured HR in the absence of Ku80. We find that the frequency of intrachromosomal HR is not affected by the absence of Ku80. Previous work has clearly implicated the Ku heterodimer in Agrobacterium-mediated T-DNA transformation of yeast. Surprisingly, ku80 mutant plants show no defect in the efficiency of T-DNA transformation of plants with Agrobacterium, showing that an alternative pathway must exist in plants.

Agrobacterium tumefaciens↗
PubMed2000

Morbidity and the impact on daily activities associated with catheter drainage after acute urinary retention.

OBJECTIVE: To evaluate the effect on quality of life of being discharged home with a catheter before definitive treatment in patients with acute urinary retention (AUR). PATIENTS AND METHODS: Patients attending the emergency department with AUR were assessed and discharged home with a catheter if they fulfilled predetermined criteria. They were admitted to the day-care unit for urological assessment and completed a disease-specific quality-of-life questionnaire. RESULTS: Of 101 patients presenting to the emergency department in AUR, 84 were sent home after catheterization (83%); 78 (93%) patients completed the questionnaire. The major side-effects reported were urinary leak (46%), mild haematuria (44%), urgency (42%), pain around the penis (42%), painful erection (31%) and catheter blockage (26%). Only 12% of patients felt having a catheter was very inconvenient and 93% would find it acceptable to have a catheter in future. CONCLUSION: A significant minority of patients discharged home with a catheter had side-effects related to their catheter but were not greatly inconvenienced, and their capacity to carry out normal daily activities was not impaired. The immediate discharge of patients in AUR and planned treatment will enable better use of inpatient urology resources.

Activities of Daily Living↗
PubMedDate not supplied

Effect of training on muscle strength and motor function in the elderly.

Overall muscle strength and mass decline 30-50% between the ages of 30 and 80. The loss of muscle mass, the so called sarcopenia, accounts for most of the observed loss of strength. A reduced specific muscle force has also been observed but its contribution to the decrease in strength with age remains unclear. The loss of muscle tissue is due to a decrease in the number of muscle fibres and atrophy of the type II muscle fibres. The declining strength reduces the capacity to carry out basic activities of daily life and puts people at risk for falls and dependence. Resistive strength training greatly increases muscle strength even in very old people. It produces muscle fibre hypertrophy and improves neural factors involved in force production. The recovered strength in turn enhances the physical performance and allows a more active and independent life towards the end of the life span.

Adult↗
PubMed2004

Inhibition of apoptosis in acute promyelocytic leukemia cells leads to increases in levels of oxidized protein and LMP2 immunoproteasome.

On reaching maturity, animal organs cease to increase in size because of inhibition of cell replication activities. It follows that maintenance of optimal organ function depends on the elimination of oxidatively damaged cells and their replacement with new cells. To examine the effects of oxidative stress and apoptosis on the accumulation of oxidized proteins, we exposed acute promyelocytic leukemia cells to arsenic trioxide (As(2)O(3)) in the presence and absence of a general caspase inhibitor (benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone), which is known to inhibit caspase-induced apoptosis. We confirm that treatment of cells with As(2)O(3) induces apoptosis and leads to the accumulation of oxidized proteins. Furthermore, inhibition of caspase activities prevented As(2)O(3)-induced apoptosis and led to a substantial increase in accumulation of oxidized proteins. Moreover, inhibition of caspase activity in the absence of As(2)O(3) led to elevated levels of the LMP2 immunoproteasome protein. We also show that caspase inhibition leads to increases in the levels of oxidized proteins obtained by treatments with hydrogen peroxide plus ferrous iron. Collectively, these results suggest the possibility that an age-related loss in capacity to carry out apoptosis might contribute to the observed accumulation of oxidized proteins during aging and in age-related diseases.

Aging↗
PubMed1980

Glyoxylate cycle in toad urinary bladder: possible stimulation by aldosterone.

A homogenate of the toad urinary bladder epithelial cell layer has the two enzymatic activities unique to the glyoxylate cycle--isocitrate lyase (threo-Ds-isocitrate glyoxylate-lyase, EC 4.1.3.1) and malate synthase [L-malate glyoxylate-lyase (CA-acetylating), EC 4.1.3.2]--as well as the capacity to carry out CN-insensitive palmitoyl-CoA oxidation. When tissue is incubated in the presence of a fatty acid substrate, tissue glycogen levels increase. Additionally, in the presence of aldosterone, glycogen levels are higher. These data demonstrate the presence of glyoxylate cycle enzymes in tissue of a higher animal and raise the possibility that such tissue can convert lipid to carbohydrate.

Aldosterone↗
PubMed1986

Survival of UV-irradiated mammalian cells correlates with efficient DNA repair in an essential gene.

The survival of UV-irradiated mammalian cells is not necessarily correlated with their overall capacity to carry out DNA repair. Human cells typically remove 80% of the pyrimidine dimers produced by a UV dose of 5 J/m2 within 24 hr. In contrast, a Chinese hamster ovary (CHO) cell line survives UV irradiation equally well while removing only 15% of the dimers. Using a newly developed technique to measure dimer frequencies in single-copy specific sequences, we find that the CHO cells remove 70% of the dimers from the essential dihydrofolate reductase (DHFR) gene but only 20% from sequences located 30 kilobases or more upstream from the 5' end of the gene in a 24-hr period. Repair-deficient human cells from xeroderma pigmentosum complementation group C (XPC) are similar to the CHO cells in overall repair levels, but they are extremely sensitive to killing by UV irradiation. In the XPC cells, we find little or no repair in the DHFR gene; in contrast, in normal human fibroblasts and epidermal keratinocytes, greater than 80% of the dimers induced in the gene by 20 J/m2 are removed in 24 hr. Since the CHO and normal human cells exhibit similar UV resistance, much higher than that of XPC cells, our findings suggest a correlation between efficient repair of essential genes and resistance to DNA-damaging agents such as UV light.

Animals↗
PubMed1996

Cloning, sequencing, and expression in escherichia coli of OxlT, the oxalate:formate exchange protein of Oxalobacter formigenes.

OxlT is the oxalate/formate exchange protein that represents the vectorial component of a proton-motive metabolic cycle in Oxalobacter formigenes. Here we report the cloning and sequencing of OxlT and describe its expression in Escherichia coli. The OxlT amino acid sequence specifies a polytopic hydrophobic protein of 418 residues with a mass of 44,128 daltons. Analysis of hydropathy and consideration of the distribution of charged residues suggests an OxlT secondary structure having 12 transmembrane segments, oriented so that the N and C termini face the cytoplasm. Expression of OxlT in E. coli coincides with appearance of a capacity to carry out the self-exchange of oxalate and the heterologous, electrogenic exchange of oxalate with formate. The unusually high velocity of OxlT-mediated transport is also preserved in E. coli. We conclude that the essential features of OxlT are retained on its expression in E. coli.

Amino Acid Sequence↗
PubMed1981

Effects of a transfusion with a blood substitute (Fluosol-DA, 20%) on cerebral circulation in the monkey.

Local cerebral blood flow (lCBF) and electroencephalogram were monitored in six monkeys after a transfusion using a perfluorochemical suspension (Fluosol-DA, 20%) that has been manufactured as a blood substitute and is known to be synthetic, biologically inert, and nontoxic and to have a high capacity for carrying oxygen. The animals were mechanically ventilated, and blood gases were maintained at physiological levels. Fluosol-DA, 20% was administered either by an exchange transfusion of 20 ml/kg or by an infusion of 8 ml/kg followed by an exchange transfusion of 12 ml/kg. lCBF was measured using the hydrogen clearance technique. An equation was proposed to estimate the tissue-blood partition coefficient of hydrogen; this coefficient is considered to be dependent upon the amount of perfluorochemicals in the blood and was used to calculate lCBF. Systemic blood pressure, pulse rate, central venous pressure, electroencephalogram, and gas analysis of the blood from the femoral artery, the femoral vein, and the superior sagittal sinus showed little change throughout the experiment. lCBF was increased by 12% (p less than 0.005) after the infusion of Fluosol-DA, 20% of 8 ml/kg and by 31% (p less than 0.02) after the exchange transfusion. Hyperventilation reduced lCBF significantly (p less than 0.005), which implies that the reactivity of the cerebral blood vessels to hypocarbia was not impaired by the administration of FLuosol-DA, 20%. Both the results of this study and the physical properties of Fluosol-DA, 20% suggest that this blood substitute can safely be used for normal human brains and that it might also be effective for ischemic brains.

Animals↗