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PubMed1991

Binding of proteins of HeLa S3 cell extract to oligonucleotides containing the consensus interferon-response sequence (IRS) and to the IRS-containing fragment of the human c-myc gene.

The human c-myc proto-oncogene was recently found to contain a regulatory sequence similar to the consensus interferon-response sequence (IRS) of interferon-activating genes. Binding of regulatory protein(s) to this sequence of cloned fragment of c-myc, lacking the main part of 5'-nontranscribing region, regulates in vitro transcription from I1/I2 initiation sites located in the first intron of the gene. Here, we have shown that HeLa S3 nuclear extract contains different protein factors, at least two, that bind preferentially to the IRS sequence of either the c-myc gene or the interferon-dependent 6-16 gene. Moreover, each of these factors 'cross-binds' to the region of the other gene, although affinity of this interaction is lower. Binding constants of these proteins to oligonucleotide fragments of c-myc and 6-16 genes were determined. In vitro transcription of the human full-length c-myc gene (i.e. the gene containing the complete 5'-noncoding region) initiated from I1/I2 sites, that is controlled by the IRS region, was demonstrated to be blocked. A possible physiological role for the mechanisms described is discussed.

Base Sequence↗
PubMed1996

Quinaldine 4-oxidase from Arthrobacter sp. Rü61a, a versatile procaryotic molybdenum-containing hydroxylase active towards N-containing heterocyclic compounds and aromatic aldehydes.

Quinaldine 4-oxidase from Arthrobacter sp. Rü61a, an inducible molybdenum-containing hydroxylase, was purified to homogeneity by an optimized five-step procedure. Molecular oxygen is proposed as physiological electron acceptor. Electrons are also transferred to artificial electron acceptors with E'o > -8 mV. The molybdo-iron/sulfur flavoprotein regiospecifically attacks its N-heterocyclic substrates: isoquinoline and phthalazine are hydroxylated adjacent to the N-heteroatom at Cl, whereas quinaldine, quinoline, cinnoline and quinazoline are hydroxylated at C4. Additionally, the aromatic aldehydes benzaldehyde, salicylaldehyde, vanillin and cinnamaldehyde are oxidized to the corresponding carboxylic acids, whereas short-chain aliphatic aldehydes are not. Quinaldine 4-oxidase is compared to the two molybdenum-containing hydroxylases quinoline 2-oxidoreductase from Pseudomonas putida 86 [Tshisuaka, B., Kappl, R., Hüttermann, J. & Lingens, F. (1993) Biochemistry 32, 12928-12934] and isoquinoline 1-oxidoreductase from Pseudomonas diminuta 7 [Lehmann, M., Tshisuaka, B., Fetzner, S., Röger, P. & Lingens, F. (1994) J. Biol. Chem. 269, 11254-11260] with respect to the substrates converted and the electron-acceptor specificities. These dehydrogenases hydroxylate their N-heterocyclic substrates exclusively adjacent to the heteroatom. Whereas the aldehydes tested are scarcely oxidized by quinoline 2-oxidoreductase, isoquinoline 1-oxidoreductase catalyzes the oxidation of the aromatic aldehydes, although being progressively inhibited. Neither quinoline 2-oxidoreductase nor isoquinoline 1-oxidoreductase transfer electrons to oxygen. Otherwise, the spectrum of electron acceptors used by quinoline 2-oxidoreductase and quinaldine 4-oxidase is identical. However, isoquinoline 1-oxidoreductase differs in its electron-acceptor specificity. Quinaldine 4-oxidase is unusual in its substrate and electron-acceptor specificity. This enzyme is able to function as oxidase or dehydrogenase, it oxidizes aldehydes, and it catalyzes the nucleophilic attack of N-containing heterocyclic compounds at two varying positions depending on the substrate.

Aldehydes↗
PubMed1993

Histamine evokes greater increases in phosphatidylinositol metabolism and catecholamine secretion in epinephrine-containing than in norepinephrine-containing chromaffin cells.

Chromaffin cells have H1 histamine receptors. Histamine, acting at these receptors, increases the metabolism of inositol-containing phospholipids and stimulates catecholamine secretion from chromaffin cells. We have investigated the effects of histamine and other agents on the accumulation of inositol monophosphate (InsP1) and catecholamine secretion in purified cultures of norepinephrine-containing and epinephrine-containing bovine chromaffin cells. Histamine-stimulated InsP1 accumulation in epinephrine cells was three times greater than that in norepinephrine cells. In contrast, bradykinin caused roughly equivalent increases in InsP1 accumulation in the two chromaffin cell subtypes. Histamine-stimulated catecholamine secretion was also greater in epinephrine cells than in norepinephrine cells, whereas high K+, bradykinin, phorbol 12,13-dibutyrate, and angiotensin II all caused greater secretion from norepinephrine cells than from epinephrine cells. The density of H1 receptors in epinephrine cells was approximately three times greater than that in norepinephrine cells. The greater density of H1 receptors on epinephrine cells may account for the greater effects of histamine on InsP1 accumulation and catecholamine secretion in these cells.

Adrenal Glands↗
PubMed1970

Comparison of a blood culture system containing liquoid and sucrose with systems containing either reagent alone.

By utilizing parallel culture methods on multiple blood specimens, three blood culture systems were evaluated for their ability to allow rapid recovery of organisms. The same base medium was used for all three systems. System or flask 1 contained base medium with Liquoid added, flask 2 contained base medium with sucrose added, and flask 3 contained both Liquoid and sucrose. During the study period, there were 259 patients considered to have positive blood cultures. Organism recovery was accomplished from flask 1 in 214 of these patients, from flask 2 in 180 cases, and from flask 3 in 257 instances. The use of anticoagulants and osmotic stabilizers in blood culture systems is discussed in detail.

Anticoagulants↗
PubMed1987

The genome of lipid-containing bacteriophage PRD1, which infects gram-negative bacteria, contains long, inverted terminal repeats.

The bacteriophage PRD1 is a lipid-bearing phage that infects a wide variety of gram-negative bacteria, including Escherichia coli and Salmonella typhimurium when they contain the appropriate plasmid. It contains a linear duplex DNA molecule that is covalently bound by its 5' ends to a terminal protein. We report here that the PRD1 genome contains a 111-base-pair terminal inverted repeat which does not bear homology to that of any known linear duplex DNAs with terminal proteins. We further report that its 3' termini are susceptible to enzymatic digestion by exonuclease III.

Bacteriophages↗
PubMed1992

Lipoproteins containing the truncated apolipoprotein, Apo B-89, are cleared from human plasma more rapidly than Apo B-100-containing lipoproteins in vivo.

We have reported previously on two truncations of apolipoprotein B (apo B-40 and apo B-89) in a kindred with hypobetalipoproteinemia. Premature stop codons were found to be responsible for both apo B-40 and apo B-89, but the physiologic mechanisms accounting for the reduced plasma concentrations of these proteins have not been determined in vivo. This study investigates the metabolism of apo B-89 in two subjects heterozygous for apo B-89/apo B-100 and in one apo B-40/apo B-89 compound heterozygote. In both heterozygotes total apo B concentration is approximately 30% of normal and apo B-89 is present in lower concentrations in plasma than apo B-100. After the administration of [1-13C]leucine as a primed constant infusion over 8 h, 13C enrichments of plasma leucine as well as enrichments of VLDL-, IDL-, and LDL-apo B-89 leucine and VLDL-, IDL-, and LDL-apo B-100 leucine were measured over 110 h. Enrichment values were subsequently converted to tracer/tracee ratios and a multicompartmental model was used to estimate metabolic parameters. In both apo B-89/apo B-100 heterozygotes apo B-89 and apo B-100 were produced at similar rates. Respective transport rates of apo B-89 and apo B-100 for subject 1 were 2.13 +/- 0.18 and 2.56 +/- 0.13 mg.kg-1.d-1, and for subject 2, 6.59 +/- 0.18 and 8.23 +/- 0.39 mg.kg-1.d-1. However, fractional catabolic rates of VLDL, IDL, and LDL particles containing apo B-89 were 1.4-3 times higher than the rates for corresponding apo B-100-containing particles. Metabolic parameters of apo B-89 in the apo B-40/apo B-89 compound heterozygote compared favorably with those established for apo B-89 in apo B-89/apo B-100 heterozygotes. Thus, the enhanced catabolism of VLDL, IDL, and LDL particles containing the truncated apolipoprotein is responsible for the relatively low levels of apo B-89 seen in these subjects.

Adult↗
PubMed1984

Thymic hormone-containing cells. V. Immunohistological detection of metallothionein within the cells bearing thymulin (a zinc-containing hormone) in human and mouse thymuses.

Using an immunofluorescence (IF) assay, the presence of metallothionein (MT) was investigated in sections of normal and pathologic human thymuses as well as in cultures of thymic epithelial cells. This protein, known to have a high binding affinity for class II B transitional metals, such as zinc, was detected in the epithelial component of the thymus. Moreover, double labeling experiments with the anti-MT and an anti-thymulin monoclonal antibody showed that all cells containing thymulin, a thymic hormone whose active structure is known to contain zinc, also exhibited large amounts of metallothionein. These results, together with the fact that zinc and thymulin have been detected in the same type of cell organelles, lead to the conclusion that the MT present in thymic epithelial cells might be involved in the mechanism of zinc storage in these cells, thus favoring the secretion of thymulin in its biologically active, zinc-containing form.

Animals↗
PubMed2006

Zero-valent iron treatment of RDX-containing and perchlorate-containing wastewaters from an ammunition-manufacturing plant at elevated temperatures.

The use of zero-valent iron for treating wastewaters containing RDX and perchlorate from an army ammunition plant (AAP) in the USA at elevated temperatures and moderately elevated temperature with chemical addition was evaluated through batch and column experiments. RDX in the wastewater was completely removed in an iron column after 6.4 minutes. Increasing the temperature to 75 degrees C decreased the required retention time to 2.1 minutes for complete RDX removal. Perchlorate in the wastewater was completely removed by iron at an elevated temperature of 150 degrees C in batch reactors in 6 hours without pH control. Significant reduction of perchlorate by zero-valent iron was also achieved at a more moderate temperature (75 degrees C) through use of a 0.2 M acetate buffer. Based on the evaluation results, we propose two innovative processes for treating RDX-containing and perchlorate-containing wastewaters: a temperature and pressure-controlled batch iron reactor and subsequent oxidation by existing industrial wastewater treatment plant; and reduction by consecutive iron columns with heating and acid addition capabilities and subsequent oxidation.

Explosive Agents↗
PubMed1997

The effect of zinc-containing chewing gum on volatile sulfur-containing compounds in the oral cavity.

Volatile sulfur-containing compounds (VSC) are known to constitute the major component of halitosis. Aqueous solutions of zinc salts have been shown to reduce the levels of VSC produced orally. The aim of the present study was to examine whether zinc could be made available in the oral cavity and inhibit VSC production when delivered by a chewing gum. VSC measurements were carried out on the 'morning breath' of 11 test subjects and re-examined after the use of test solutions containing 0.02% zinc chloride, 0.2% chlorhexidine, or water or the use of chewing gums containing 2 mg, 0.5 mg, or 0 mg zinc acetate. The results showed that similar amounts of zinc in mouthrinses or chewing gum had the same effect, with a reduction of the oral VSC of 45%. Chewing gum thus seems to be a viable alternative for delivering zinc to reduce VSC levels in the oral cavity.

Adolescent↗
PubMed1984

The measurement of FAD-containing mono-oxygenase activity in microsomes containing cytochrome P-450.

Antibodies to NADPH-cytochrome P-450 reductase have been used to essentially abolish the contribution of cytochrome P-450 to xenobiotic metabolism by mammalian microsomes. This permits the determination of the activity of the FAD-containing mono-oxygenase and the stoichiometry between substrate, O2 and NADPH, in the microsomal membrane, and in the absence of cytochrome P-450-dependent activity. FAD-containing mono-oxygenase oxidation rates were determined for sulphur- and nitrogen-containing substrates, including: thiols; sulphides; thioamides; primary, secondary and tertiary amines; hydrazines. Although the enzyme in mouse, rabbit, rat and pig microsomes displays similar substrate specificity, some catalytic characteristics are different between species and tissues.

Animals↗
PubMed2002

[Multiresidue analysis of nitrogen-containing and sulfur-containing pesticides in agricultural products using dual-column GC-NPD/FPD].

We investigated simultaneous analytical methods for pesticide residues in large numbers of agricultural products samples. Extraction of each sample with acetonitrile was followed by a salting-out step using a graduated cylinder. The test solution was cleaned up with gel permeation chromatography (GPC), which separated the pesticide eluate into 2 fractions, and then with a tandem mini-column. Analysis was done with a dual-column GC equipped with a dual NPD and FPD (S mode) detector. Use of the Siltek-deactivated liner, guard column, and Y connector, and Silcosteel-treated NPD jet was effective for preventing the breakdown of sulfur-containing pesticides. Recoveries of 87 nitrogen-containing and sulfur-containing pesticides from fortified spinach, tomato, apple, strawberry and brown rice, ranged from 71 to 127% with RSD values of 1-24%, except for recoveries of aldicarb, amitraz, ethiofencarb, imazalil, propamocarb and triflumizole. Detection limits of pesticides were very good (0.3-5 ppb (NPD) and 2-20 ppb (FPD)) for routine analysis of pesticide residues in foods. Surveillance of pesticides in agricultural products was carried out by using the present method. From 22 out of 33 samples, 21 pesticides (43 in total) were detected. The results indicated that the present method can be applied as an efficient and reliable means for monitoring pesticide residues in agricultural products.

Chromatography, Gas↗
PubMed2001

Comparison of the effect on acne with a combiphasic desogestrel-containing oral contraceptive and a preparation containing cyproterone acetate.

OBJECTIVE: To investigate the effect of a combiphasic oral contraceptive containing ethinylestradiol and desogestrel (combiphasic EE/DSG) on acne, compared with a preparation containing ethinylestradiol and cyproterone acetate (EE35/CPA). METHODS: An open, randomized, group-comparative, multicenter study was carried out, with 172 women randomized to treatment with either combiphasic EE/DSG (25 microg desogestrel and 40 microg ethinylestradiol for 7 days followed by 125 microg desogestrel and 30 microg ethinylestradiol for 15 days) or EE35/CPA (2.0 mg cyproterone acetate and 35 microg ethinylestradiol for 21 days). Assessments were performed at pretreatment and after cycles 3 and 6. RESULTS: The number of comedones, papules, pustules and nodules significantly decreased in both groups over the 6-month study. Compared with pretreatment (= 100%), the relative numbers of comedones, papules, pustules and nodules at cycle 6 significantly decreased to 37%, 38%, 19% and 12.5% in the combiphasic EE/DSG group and to 24%, 36%, 17% and 1% in the EE35/CPA group, respectively. All reductions were statistically significant (p < or = 0.003) at both cycles 3 and 6, except for nodules at cycle 6 with combiphasic EE/DSG, which probably resulted from differences between the treatment groups at baseline. There were no statistically significant differences between the two treatments. In both groups, the majority of women with severe acne shifted to a less severe acne category. CONCLUSIONS: Combiphasic EE/DSG progressively reduced the number and severity of acne lesions during the six cycles of treatment. The reduction in acne with the combiphasic oral contraceptive was comparable to a preparation containing the antiandrogen cyproterone acetate.

Acne Vulgaris↗
PubMedDate not supplied

Cycle control, tolerability, and satisfaction among women switching from 30-35 microg ethinyl estradiol-containing oral contraceptives to the triphasic norgestimate/25 microg ethinyl estradiol-containing oral contraceptive Ortho Tri-Cyclen LO.

OBJECTIVE: To determine cycle control, tolerability, and satisfaction among women (aged 18-45) switching from oral contraceptives (OCs) containing 30-35 microg ethinyl estradiol (EE) to Ortho Tri-Cyclen LO (norgestimate 180/215/250 microg/EE 25 microg) and Loestrin Fe 1/20 (norethindrone acetate 1 mg/EE 20 microg). DESIGN: A subset of patients from a study comparing Ortho Tri-Cyclen LO (N = 864) with Loestrin Fe 1/20 (N = 565) was analyzed. The subset was defined as those who had taken a 30-35 microg EE-containing OC within 60 days of study start. The total number of cycles of exposure for the subset was 6,054 for Ortho Tri-Cyclen LO and 3,814 for Loestrin Fe 1/20. Additional analyses evaluated switchovers from Ortho Tri-Cyclen to Ortho Tri-Cyclen LO (N = 111). MAIN OUTCOME MEASURES: Cycle control was assessed by daily diary cards reporting the frequency, severity, and duration of bleeding/spotting. Discontinuation rates due to adverse events (AEs) were considered to reflect tolerability. Satisfaction was evaluated by questionnaire. RESULTS: The proportion of cycles in which subjects experienced breakthrough bleeding and/or spotting was significantly lower with Ortho Tri-Cyclen LO than Loestrin Fe 1/20. Discontinuations due to AEs and serious AEs were comparable for Ortho Tri-Cyclen LO (3.4% and 0.6%, respectively) and Loestrin Fe 1/20 (3.2% and 0.7%, respectively). More women on Ortho Tri-Cyclen LO versus Loestrin Fe 1/20 were very or somewhat satisfied at Cycle 6 (86% vs. 81.1%; P < 0.05) and last visit (81.6% vs. 78.1%; P < 0.05). At Cycle 6, 89.3% of Ortho Tri-Cyclen to Ortho Tri-Cyclen LO switchovers were very or somewhat satisfied, and 72.6% desired to continue taking Ortho Tri-Cyclen LO after study conclusion. Conclusions-Switchovers from OCs containing 30-35 microg EE to Ortho Tri-Cyclen LO had excellent cycle control and tolerability, and were satisfied.

Adolescent↗
PubMed2004

Superiority of a combined contraceptive containing drospirenone to a triphasic preparation containing norgestimate in acne treatment.

This double-blind study compared the efficacy and tolerability of a combined oral contraceptive containing 30 microg ethinyl estradiol and 3 mg drospirenone (EE/DRSP; Yasmin) with a triphasic preparation containing 35 microg EE and 0.180, 0.215, 0.250 mg norgestimate (EE/NGM; Pramino, also known as Ortho Tri-Cyclen) in the treatment of acne vulgaris. The combined presence of antiandrogenic and antimineralocorticoid activities of drospirenone is unique to this novel progestin in that these characteristics most closely resemble those of progesterone. The study was designed to show that EE/DRSP was noninferior or superior to EE/NGM as to the relative decrease from baseline to cycle 6 in percentage of inflammatory and total lesion counts and the investigators' assessment of acne improvement. Other outcomes included subjects' assessment of therapeutic effect, sebum production, and hormone levels. Female subjects were randomized to EE/DRSP (n = 568) or EE/NGM (n = 586) for 6 treatment cycles, consisting of 21 consecutive days of hormone intake, followed by 7 hormone-free days. The preparation containing EE/DRSP was superior to EE/NGM for reduction in total lesion count (-3.3% in favor of EE/DRSP [95% CI, -6.5 to -0.1; P = .020]) and for investigators' assessment of therapeutic effect on facial acne (+3.6% in favor of EE/DRSP [95% CI, 0.8 to 6.3; P = .006]). The 2 preparations were comparable as to their decreases in inflammatory lesion count. Evaluation of the effect of treatment by subjects was consistent with that of the investigators. Furthermore, both preparations increased the level of sex hormone-binding globulin (SHBG) and decreased the levels of androgens, changes typically associated with acne improvement. Both preparations were well tolerated. In conclusion, owing to the unique pharmacologic activities of drospirenone, the combined oral contraceptive EE/DRSP provides an effective treatment option in female patients with mild to moderate acne.

Acne Vulgaris↗
PubMed2006

Neuropsychiatric adverse events after switching from an antiretroviral regimen containing efavirenz without tenofovir to an efavirenz regimen containing tenofovir: a report of nine cases.

The combination of tenofovir (TDF) and efavirenz (EFV) has not been associated with any pharmakokinetic interaction or with enhancement of neuropsychiatric disturbances. We report nine cases of neuropsychiatric intolerance occurring early after a switch from an antiretroviral regimen without TDF to an EFV and TDF-containing regimen. Nine HIV-1-infected patients were treated with an EFV-containing regimen for a median duration of 31 months without any EFV-related central nervous system (CNS) effects. They were switched to an EFV-TDF-containing regimen because of lipodystrophy (n=2) and/or the wish to simplify to a once-daily regimen (n=9). Moderate to severe neuropsychiatric events occurred immediately (<48 hours) after TDF initiation in five patients and 2 weeks to 24 months after the switch in the remaining four patients. Treatment modifications occurred in six patients (switch to EFV-nevirapine [n=3], TDF-zidovudine [n=2] or treatment discontinuation [n=1]), leading to a marked improvement of CNS intolerance. Treatment remained unchanged in three patients; two patients experienced chronic persistent sleeping disorders and one patient underwent a spontaneous improvement of symptoms within 2 weeks. EFV plasma concentrations, which were available in two patients before the switch and in four patients after the switch, remained in the therapeutic range. Although the exact mechanism of these symptoms remains hypothetical, neuropsychiatric disorders could be either a consequence of an unexplained interaction between EFV and TDF or an infrequent TDF-related side effect. The incidence of these side effects needs to be evaluated in large databases or pharmacokinetic studies.

Adenine↗
PubMed1990

[Hallucinogenic psilocybine containing mushrooms. Toxins contained in Danish wild mushrooms].

A number of the wild Danish mushrooms contain the hallucinogenic agent psilocybin which resembles LSD in many ways. The commonest of these are the "liberty cap" or "magic mushrooms" (Psilocybe semilanceata). On the basis of experience from USA and western Europa, increase in employment of this mushrooms as a hallucinogenic intoxicant may be anticipated in Denmark. The history, epidemiology, botany and pharmacology of the mushroom are reviewed. Clinical pictures and treatment are described for: 1) Acute poisoning with psilocybin-containing fungi, 2) Late sequelae of consumption of psilocybin-containing fungi and 3) Poisoning with more poisonous fungi on account of incorrect identification. General practitioners, duty roster doctors, doctors in casualty departments and in acute psychiatric departments should be aware of these problems. Intoxication with psilocybin may be confused with panic anxiety or euphoria in persons with mydriasis and other sympathomimetic symptoms. The possibility of more serious mushroom poisoning on account of incorrect identification should be borne in mind.

Denmark↗
PubMed1989

In vitro transformation of apoA-I-containing lipoprotein subpopulations: role of lecithin:cholesterol acyltransferase and apoB-containing lipoproteins.

Two populations of apoA-I-containing lipoproteins are found in plasma: particles with apoA-II [Lp(AI w AII)] and particles without apoA-II [Lp(AI w/o AII)]. Both are heterogeneous in size. However, their size subpopulation distributions differ considerably between healthy subjects and patients with coronary artery diseases. The metabolic basis for such alterations was studied by determining the role of lecithin:cholesterol acyltransferase (LCAT) and apoB-containing lipoproteins (LpB) in the size subpopulation distributions of Lp(AI w AII) and Lp(AI w/o AII). ApoB-free and LCAT-free plasmas, prepared by affinity chromatography, and whole plasma were incubated at 4 degrees C and 37 degrees C for 24 hr. After incubation, Lp(AI w AII) and Lp(AI w/o AII) were isolated by anti-A-II and anti-A-I immunosorbents. Their size subpopulation distributions were studied by nondenaturing gradient polyacrylamide gel electrophoresis. At 4 degrees C most Lp(AI w AII) particles were in the range of 7.0-9.2 nm Stokes diameter. Incubation of plasma at 37 degrees C resulted in an overall enlargement of particles up to 11.2 nm and larger. These particles were enriched with cholesteryl ester and triglyceride and depleted of phospholipids and free cholesterol. Removal of LpB or LCAT from plasma prior to incubation greatly reduced their enlargement. At 4 degrees C, Lp(AI w/o AII) contained mostly particles of 8.5 and 10.1 nm. Incubation at 37 degrees C abolished both subpopulations with the formation of a new subpopulation of 9.2 nm. This transformation was identical in apoB-free plasma but was not seen in LCAT-free plasma. Our study shows that transformation of Lp(AI w AII) requires both LCAT and LpB. However, LpB is not necessary for the transformation of Lp(AI w/o AII) in vitro. The relevance of these in vitro studies to in vivo lipoprotein metabolism was demonstrated in a subject with hepatic triglyceride lipase deficiency.

Adult↗
PubMed1987

Studies on the physical state of water in living cells and model systems. VI. Concentration-dependent sustained volume changes of dialysis sacs containing aqueous solution of native and denatured protein, gelatin, and oxygen-containing polymers immersed in solutions of Na salt and of sugar and sugar alcohol.

In this paper we studied the volume changes of dialysis sacs containing concentrated solutions of native and denatured proteins and of oxygen-containing polymers after immersion in aqueous solution of Na-citrate, D-glucose, and sorbitol of varying concentration. The results confirm the theory of cell volume regulation: volume changes of living cells in different solutions represent a balance between the tendency of intracellular proteins -- which exist in the fully extended conformation -- to polarize, sorb, and draw into the sac or cell more water and the opposite tendency to lose water from the sac or cell created by the lower level of the solutes in the cell or sac water than in the external medium. The lower level of the solutes is the consequence of the reduced solvency of the polarized water in the sac or cell water for large and complex solutes like sugar and free amino acids. This study adds another important physico-chemical attribute of the living cell that can be duplicated by aqueous solutions of gelatin, oxygen-containing polymers like PEO and PEG as well as urea-denatured proteins but not, or only weakly so, by aqueous solutions of native proteins or SDS-denatured proteins.

Animals↗