PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “EXTRACELLULAR SPACE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 451 records · Page 25Linked to original sources
PubMed1986

Brain extracellular space: developmental studies in rat optic nerve.

Analysis of neural activity-dependent fluctuations in K+, H+, and ECS dimensions in the developing RON has revealed major changes during the first two to three postnatal weeks. The emergence of the adult ceiling level for evoked extracellular K+ (10 to 12 mM) and significant ECS shrinkage are roughly correlated in time with the proliferation and maturation of glial cells in this structure. This observation and others have led to the hypothesis that ECS shrinkage depends upon electrolyte and water transport into glial cells with subsequent swelling. Development of the adult K+ ceiling level may also depend upon glial cells, but it is likely that other factors contribute to this homeostatic mechanism. Marked alterations in activity-dependent pHo shifts were seen with development and may be related to changes in the activity of carbonic anhydrase in this structure. The technological means are at hand to pursue these questions vigorously in an effort to provide further insight into the mechanisms of ionic and fluid homeostasis of brain ECS, and the developing RON appears to be a useful model system in this regard.

Aging↗
PubMed1996

[Distribution of irrigating fluid in intracellular and extracellular spaces during transurethral prostatectomy II--TUR syndrome and hyponatremia].

Thirty four patients undergoing transurethral resection of the prostate (TURP) under spinal anesthesia were assigned to a TUR syndrome (TURS) group (n = 7) or an asymptomatic (ASP) group (n = 27) depending on the clinical manifestations of the TUR syndrome. Blood loss and distribution of absorbed irrigating fluid (3% sorbitol-Uromatic S, 170 mOsm.kgH2O-1, Baxter) were computed together with serum osmolality, blood urea nitrogen and hematocrit. Postoperative serum sodium concentration and hematocrit were significantly lower in the TURS group than in the ASP group (124 +/- 8.7 vs. 133.9 +/- 5.9 mOsm.l-1 and 26. 8 +/- 4.2 vs. 35.0 +/- 4.6%, respectively). Postoperative serum osmotic pressure did not differ between the groups despite the difference in sodium concentration because 3% sorbitol could contribute to osmoles in the serum. The volume of irrigating fluid absorbed and its distribution into the intracellular space (delta ICF) did not differ between the groups. However, blood loss was significantly greater in the TURS group than in the ASP group (1457 +/- 434 ml vs. 173 +/- 450 ml, P < 0.01), and consequently extracellular fluid (ECF) volume was significantly reduced in the TURS group (-354 +/- 1201 ml vs. 802 +/- 1302 ml, P < 0.05). Thus, massive blood loss and reduced ECFs rather than dilutional hyponatremia, are thought to contribute to clinical manifestation of the TUR syndrome.

Aged↗
PubMedDate not supplied

[Release of protein into the extracellular space as a nonspecific response to stress in Escherichia coli].

This paper is concerned with the kinetics of excretion of fluorescent tryptophan-containing proteins from Escherichia coli cells kept in physiological saline at room temperature or incubated at 42, 48, and 55 degrees C. The kinetic curves of the extracellular concentration of protein can be described by parameters T and C, where C is the stationary extracellular concentration of the protein and T is the time in which the given concentration is reached. T was found to be a variable, and C was a constant independent of the type and strength of the stress. During the protein release, the viability of the cells was maintained at the initial level, but, after the concentration of the protein reached a stationary value, the culture cells died exponentially. All this allows the protein release into extracellular medium to be considered as a nonspecific response of E. coli to stress. The protein excretion was analyzed with reference to the data on the kinetics of release of other UV-absorbing compounds from the cells.

Adaptation, Physiological↗
PubMed1994

Mutation analysis of the C-terminal vacuolar targeting peptide of tobacco chitinase: low specificity of the sorting system, and gradual transition between intracellular retention and secretion into the extracellular space.

The C-terminal propeptide of tobacco (Nicotiana tabacum) chitinase A has been shown to be necessary and sufficient for targeting of chitinases to the plant vacuole. The sequence specificity of this vacuolar targeting peptide (VTP) has now been analysed using transient expression of chitinases in Nicotiana plumbaginifolia protoplasts. An extracellular cucumber chitinase, previously used as a secreted reporter protein in transgenic tobacco, was also secreted into the incubation medium by the transiently transformed protoplasts. Addition of six to seven amino acids at the C-terminus to generate the VTP of tobacco chitinase A were sufficient to cause retention of most of the cucumber chitinase within the protoplasts. The chitinase A itself, as well as a mutant lacking the N-terminal chitin-binding domain, were retained to 80% in the protoplasts when low concentrations of the plasmid were used in the transient expression system. At high concentrations of plasmid, causing high levels of transiently expressed chitinase, retention was reduced, indicating saturation of the sorting system. Deletion of the C-terminal methionine did not affect the intracellular location, but deletion of even a single internal amino acid of the VTP caused predominantly secretion of tobacco chitinase A. In contrast, exchanges of amino acids in the VTP as well as substitution of the VTP with random sequences had intermediary effects that covered the whole range from retention to secretion. The results suggest that the sorting system responsible for the diversion of secretory proteins to the vacuole has a low specificity for the sequence of C-terminal targeting peptides, and that sequence changes in the VTP allow a gradual transition from vacuolar retention to secretion.

Amino Acid Sequence↗