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PubMed2005

Influence of hepatitis C virus infection on soluble cellular adhesion molecules in hemodialysis patients.

BACKGROUND/AIMS: Higher levels of soluble cellular adhesion molecules have been found to be a strong indicator of endothelial dysfunction and atherosclerosis in the general population. In hemodialysis patients, soluble cellular adhesion molecules have been found at higher levels as well. Such an increase has been considered as a sign of chronic inflammation. Chronic viral hepatitis C (HCV) infection, highly prevalent in hemodialysis patients, is also a disease that can induce chronic inflammation. We conducted a cross-sectional association study of soluble cellular adhesion molecules and hepatitis C in maintenance hemodialysis patients. METHODS: A total of 87 stable hemodialysis patients were included in this study, mean age was 60.0 +/- 13.7 years. Anti-HCV antibody and HCV RNA assay were done. Patients were divided into anti-HCV-positive and anti-HCV-negative groups. Predialytic serum soluble intercellular adhesion molecules-1 (sICAM-1), soluble vascular cellular adhesion molecules-1 (sVCAM-1), and soluble E-selectin were assayed by commercially available enzyme-linked immunosorbent assay (ELISA) kits. The results were correlated with other hematological and biochemical results. RESULTS: In the anti-HCV-positive group, the time on hemodialysis was longer (105.5 +/- 65.7 vs. 49.2 +/- 44.0 months, p = 0.001). The sICAM-1, sVCAM-1 and E-selectin levels were higher in the anti-HCV-positive group. HCV infection was determined as an independent determinant of sICAM-1 and sVCAM-1 by multiple linear regression analysis. CONCLUSION: Elevated serum soluble cellular adhesion molecules are multifactorial in hemodialysis patients. The role of HCV infection must be considered. The clinical significance and implications of soluble cellular adhesion molecules remains to be elucidated.

Aged↗

PubMed1989

Dynamic changes in soluble interleukin-2 receptor levels after lung or heart-lung transplantation.

Activation of T-lymphocytes is accompanied by the release of interleukin-2 receptors (IL-2R) in a soluble form that can be measured as an index of the activation process. We performed a prospective, blinded study of the dynamic changes in soluble IL-2R levels in serum in 12 patients undergoing lung or heart-lung transplantation. The levels of soluble IL-2R were markedly elevated during episodes of rejection (geometric mean value X divided by SEM = 3,770 X divided by 1.06 versus 411 X divided by 1.08 U/ml for normal controls, p less than 0.0001). Levels of soluble IL-2R were 2,105 X divided by 1.16 U/ml with rejection episodes in single lung recipients versus 5,560 X divided by 1.30 in recipients of two lungs (p = 0.005). Soluble IL-2R levels were 1,468 X divided by 1.05 during episodes of nonbacterial infections, 1,879 X divided by 1.34 with bacterial infections, and 5,056 X divided by 1.08 with sepsis (p less than 0.001 for each category compared to normals). Levels of soluble IL-2R exceeded 6,750 U/ml only with rejection episodes and were greater than 4,100 U/ml either with rejection, clinical sepsis, or overwhelming bacterial infection. We conclude that marked elevations of soluble IL-2R are associated with rejection, intermediate elevations with either rejection or infection, and that low levels of soluble IL-2R exclude rejection.

Adult↗

PubMed1998

Short-term variability in the concentration of serum interleukin-6 and its soluble receptor in subjectively healthy persons.

The effects of the time of the day and breakfast on the outcome of interleukin-6 and its soluble receptor in serum were studied on 22 subjectively health volunteers. We collected blood specimens at 8.00 a.m. after an overnight fast, at 9.30 a.m. after usual breakfast, and at 11.30 a.m. A second group of volunteers (n = 20) was studied during the evening. We observed a significant decrease in the concentration of interleukin-6 after breakfast. This suggests that for assay of this analyte it is preferable to collect specimens after overnight fast. No changes were observed in the concentrations of interleukin-6 soluble receptor. Weak, but significant negative correlations were found between the age of the volunteers and the concentrations of interleukin-6 soluble receptor and between age and the ratio interleukin-6 soluble receptor/interleukin-6. The concentrations of interleukin-6 were positively and significantly correlated with age. The within-subject variability was 30% for interleukin-6, 13% for its receptor, and 33.1% for the ratio interleukin-6 soluble receptor/interleukin-6. The between-subject variability was 43.7% for interleukin-6, 22.2% for its receptor, and 60.2% for the ratio interleukin-6 soluble receptor/interleukin-6. The indices of individuality (ratio within-subject variability/between-subject variability) were calculated and found to be 0.69, 0.60, and 0.55 for interleukin-6, its soluble receptor, and the ratio interleukin-6 soluble receptor/interleukin-6, respectively. The implications of these indices with the use of health-related reference values is discussed.

Adolescent↗

PubMedDate not supplied

Combined effect of natural organic matter and surfactants on the apparent solubility of polycyclic aromatic hydrocarbons.

Both natural organic matter (NOM) and surfactants are known to enhance the apparent aqueous solubility of hydrophobic organic contaminants (HOCs) in aqueous systems. In this study, the combined effect of NOM and surfactants on enhancing the solubility of HOCs was investigated, since both may occur and affect the fate and transport of HOCs in natural aqueous environments. Experimental results indicated that the apparent solubility of naphthalene, phenanthrene, and pyrene in NOM and anionic surfactant solution was lower than their solubility in NOM solution alone. However, the apparent solubility of an HOC in NOM and nonionic surfactant solution is almost the same as the sum of the HOC's solubility in NOM solution plus its solubility in nonionic surfactant solution. The observation that apparent aqueous solubility of HOCs in NOM and anionic surfactant solution is decreased is probably due to the fact that the cations that are released when the anionic surfactant dissociates may form ion pairs with acidic or phenolic groups associated with the NOM. This serves to increase the size of hydration of these groups, thereby decreasing the effective size of the nonpolar moieties associated with the NOM, and thus decreasing hydrophobic partitioning of the HOCs into the NOM. The results presented here will help us to understand the effect of NOM and surfactants on the fate and transport of HOCs in aquatic systems.

Anions↗

PubMed2006

In silico approaches to prediction of aqueous and DMSO solubility of drug-like compounds: trends, problems and solutions.

The solubility of drugs and drug-like compounds has been the subject of extensive studies aimed at finding a way to predict solubility from molecular structure. The aqueous solubility of a drug is an important factor that influences its absorption, distribution and elimination in the body. Poor aqueous solubility often causes a drug to appear inactive and may cause other biological problems. Compound solubility in DMSO represents another serious problem in early stages of drug discovery. An appreciation of the factors affecting a compound's DMSO solubility could help in predicting the storage conditions and appropriateness of compounds for primary bioscreening programs. In silico procedures for estimation of water and DMSO solubility represent extremely useful tools for the drug discovery practitioners. In this review, we provide a critical discussion of in silico models for the prediction of DMSO and water solubility of drug-like compounds used for virtual screening. We describe the main tendencies in the field, "booming" approaches and unsolved problems. A critical analysis of the accuracy and applicability of methods is provided.

Biological Availability↗

PubMed2001

Levels of Art2+ cells but not soluble Art2 protein correlate with expression of autoimmune diabetes in the BB rat.

ART2a and ART2b are isoenzymes expressed on the surface of mature T cells and intraepithelial lymphocytes (IELs) in the rat. They exhibit both adenosine diphosphoribosyltransferase and nicotine adenine dinucleotide (NAD) glycohydrolase activities, and both can generate a transmembrane signal that modulates T cell activation. The presence or absence of ART2+ T cells modulates the expression of autoimmune diabetes in the BB rat. ART2 also circulates in a soluble form whose function is unknown. We tested the hypothesis that circulating ART2 protein regulates the expression of autoimmunity. We compared the kinetics, regulation, and source of soluble ART2 in normal rats and in rats with autoimmune diabetes. Basal levels of soluble ART2 varied greatly among strains of rats and were lowest in the diabetes-prone BB (BBDP/Wor) rat. In diabetes-resistant BB (BBDR/Wor) rats, administration of anti-ART2a antibody, which is known to induce diabetes, resulted in transient clearing of soluble ART2a that was followed rapidly by a rebound increase. Repeated treatment of BBDR/Wor rats with anti-ART2a antibody resulted in sustained supraphysiologic levels of soluble ART2a. Although the number of peripheral ART2a+ T cells is known to correlate with the expression of diabetes in BBDR/Wor rats, the level of soluble ART2a protein did not. The source of the soluble ART2 protein in the rat appeared to be the gut. The results suggest that ART2+ T cells and soluble ART2 protein may subserve different immunomodulatory functions.

ADP Ribose Transferases↗

PubMed1993

[The effect of soluble fiber dietary supplement on constipation in 3 patients with dysphagia who suffered from cerebral infarction with special reference to serum diamine oxidase activity].

Dietary supplement with soluble fibers was given to 3 patients with stroke and dysphagia and obtained improved defecation condition. These clinical effects of soluble fibers should reduce the burden of the patients and families. Long-term inaction of the gastrointestinal tract or continuation of supplementary diet without fibers will induce atrophic intestinal mucosa and abnormal intestinal function. The addition of dietary soluble fibers into supplementary diet can improve the atrophy of the intestinal mucosa and the decline in function of the intestine, constipation and meteorism. The serum diamine oxidase activity, which is regarded as a parameter of intestinal mucosal atrophy, increased with the improvement of constipation and meteorism after addition of dietary soluble fibers. We think that dietary soluble fibers are necessary, especially for the patients who have low diamine oxidase activity. The measurement of serum diamine oxidase activity should be an effective method to evaluate intestinal mucosal atrophy and estimate dietary fibers. We selected a supplementary diet, Enrich-SF, which contains Fibaron, a kind of soluble fiber, galactomannan purified from guar, because this canned supplementary diet has only one kind of soluble fiber. Some consider that soluble fibers are fermented to short-chain fatty acids in the intestinal tract, and improve the disordered bacterial flora in the intestine, resulting in more regular intestinal function. Attention should be paid to dietary fibers in cases of long-term tube feeding.

Aged↗

PubMed1993

Effects of soluble and insoluble fiber preparations isolated from oat, barley, and wheat on liver cholesterol accumulation in cholesterol-fed rats.

Effects of soluble and insoluble fiber preparations isolated from defatted oat, barley, and wheat on liver cholesterol accumulation were examined in cholesterol-fed rats. The soluble and insoluble fiber preparations were isolated by a modification of the procedure of Asp et al. Male Sprague-Dawley rats, aged 5 weeks, were fed a control diet containing 5% cellulose or diets containing soluble and insoluble fiber preparations for 9 days. Soluble fiber preparations from oat, barley, and wheat were added to diets corresponding to 1.9, 2.8, and 0.6% fiber, respectively. Insoluble fiber preparations from oat, barley, and wheat were added to diets corresponding to 3.1, 2.2, and 4.4% fiber, respectively. All of the soluble fiber preparations suppressed liver cholesterol accumulation, but they did not suppress the elevation of plasma cholesterol concentrations. A significant inverse relationship between the quantity of ingested soluble fiber and liver cholesterol accumulation was observed; n = 28, r = -0.943, p < 0.0001. None of the insoluble fiber preparations had any significant effect on liver and plasma cholesterol concentrations. These results indicate that the water-soluble fractions of oat, barley, and wheat are the active components that suppressed liver cholesterol accumulation, and that these effects are related to the quantity of ingested soluble fiber.

Animals↗

PubMed1992

Correlation of biological value of feed phosphates with their solubility in water, dilute hydrogen chloride, dilute citric acid, and neutral ammonium citrate.

Relative biological values (BV) of 36 feed phosphates were determined with female turkeys in bioassays of 21-day duration using three response criteria: weight gain, tibia ash percentage, and gain:feed ratio. Calcium phosphate, dibasic dihydrate (United States Pharmacopeia) was the reference standard. Nine mono-dicalcium phosphates (M-DCP, 21.0% phosphorus), 13 di-monocalcium phosphates (D-MCP, 18.5% phosphorus), and 14 defluorinated phosphates (DFP, 18.0% phosphorus) were evaluated. The average relative BV for M-DCP, D-MCP, and DFP samples were 97.6, 94.6, and 90.8%, respectively. Solubility of phosphates was determined by four recognized methods. The solvents were water, .4% HCl, 2.0% citric acid (CA), and neutral ammonium citrate (NAC). Water solubility of M-DCP samples was greater (67.5%) than that of D-MCP (38.8%) and DFP (8.9%) samples. Correlation of water solubility of phosphates to their relative BV was quite low, and water solubility was a poor indicator of BV. When .4% HCl was the solvent, correlation coefficients (r) were .55, .33, and .72 for M-DCP, D-MCP, and DFP, respectively. Based on these results and prediction equations, .4% HCl solubility would be inappropriate for estimating BV of M-DCP and D-MCP samples. Solubility of feed phosphates (mainly D-MCP and DFP) in 2.0% CA or NAC was positively correlated with BV; the r values were .87 to .95. Both of these solubility tests provided a good index of BV. However, it would seem inappropriate and risky to replace bioassays totally with these tests. Feed phosphate users could perform either the 2.0% CA or NAC solubility test easily as a screen for BV along with other quality control procedures (i.e., phosphorus, calcium, sodium, and fluoride determinations).

Animal Feed↗

PubMed2000

[Solubility and dissolution rate of digoxin from Digitalis lanata drug extracts] .

The influence on solubility and dissolution rate was investigated for digoxin as a model drug with a very low solubility in water. The investigations were carried out with different fractions of extracts from leaves of Digitalis lanata. These fractions differ in the composition of concomitant compounds. The solubility of digoxin from the extract fractions is increased up to 42 times, with considerable differences between the fractions. The solubility depends on the weight of the extract fraction; a limit of solubility exists. Even after separation of the solved extract components the solubility of digoxin in the residues is larger than that of the pure digoxin. The dissolution rate of digoxin of "Vorgereinigter Gesamtglykosidextrakt (VE)" and the glycosid fraction G 1 is influenced significantly, whereas digoxin in the glycosid fraction G 4 has such a degree of purity that the solubility properties are not influenced by the small amount of concomitant compounds. After 10 min already 50.4% of the digoxin in the extract fraction G 1 are dissolved, while only 21.7% of the pure digoxin are dissolved in that interval. The extract fractions exhibit different wettability properties, so that the increased dissolution rate could be attributed to improved wettability of the extract fractions. Physical mixtures of crystal-line digoxin and compounds of the extracts of the almost digoxin free fraction G 2 did not exert an influence on the dissolution behavior. Different batches of the extract fractions showed different solubility in spite of comparable digoxin content.

Cardiotonic Agents↗

PubMed1992

A rapid monoclonal antibody-based enzyme immunoassay (EIA) for the quantitative determination of soluble fibrin in plasma.

Soluble fibrin is considered as a molecular marker for intravascular fibrin formation, and impending thrombotic events. Most of the existing assays are less suitable for routine clinical applications and their specificity may be limited. We have developed a sandwich-type EIA with a fibrin-specific MoAb described by us before (Proc Natl Acad Sci 1989; 86: 8951) as the capture antibody. An other MoAb (G8; Thromb Haemostas 1988; 60: 145) with an epitope in the carboxyl-terminal sections of the fibrin alpha-chains, was labeled with peroxidase and used as the tagging antibody. The EIA is calibrated against plasma spiked with known concentrations of soluble fibrin. The time-to-result of the EIA is only 1.5 h. Concentrations as low as 0.5 micrograms soluble fibrin/ml plasma are readily measureable. Heparin has no effect on the results. Fibrinogen and fibrin(ogen) degradation products are not detected. The values of fibrinopeptide A and soluble fibrin values found with the "COA-SET soluble fibrin" assay correlated well with the soluble fibrin values found with our EIA i.e. r = 0.998 and 0.984, respectively. The run-to-run variabilities were 7.9% and 6.6% for samples with low and high soluble fibrin concentrations, respectively. The within-run variabilities were 2.5, 1.8, 4.0 and 4.6% for samples with 1, 0.5, 0.25 and 0.125 micrograms soluble fibrin/ml, respectively. The sensitivity, specificity, accuracy and short time-to-result make our EIA suitable for routine clinical applications and the monitoring of the effectivity of heparinization.

Antibodies, Monoclonal↗

PubMed2006

Soluble mouse B7-H3 down-regulates dendritic cell stimulatory capacity to allogenic T cell proliferation and production of IL-2 and IFN-gamma.

B7-H3 is a recently identified member of the B7 gene family. Its ubiquitous expression in both lymphoid and nonlymphoid tissues suggests that it could play an important role in the maintenance of self-tolerance. However, the exact function of B7-H3 is still elusive. The purpose of current study is to demonstrate the possible function of soluble mouse B7-H3 for prevention of DC-mediated T cell activation. For this purpose, we established a soluble mouse B7-H3 fusion protein (mB7h3-hIg) eukaryotic expression vector (pmB7h3-hIg) with a C-terminal human IgG1 Fc. A C57BL/6 (B6)-derived dendritic cell line (DC2.4 cells) was used for the establishment of stable transfectants for generation of soluble mB7h3-hIg. Ectopic mB7h3-hIg expression was confirmed by RT-PCR, Western blot and ELISA analyses. A 49.7 kD protein was detected by Western blot from DC2.4 cells transfected with pmB7h3-hIg. It was found that soluble mB7h3-hIg expression has no effect on cell cycling and apoptosis and the expression of CD80 and CD86 of the DC2.4 cells. However, ectopic soluble mB7h3-hIg expression was found to significantly affect the allo-stimulatory capability for DC2.4 cells. DC2.4 cells expressing soluble mB7h3-hIg showed a significant reduced allo-stimulatory capability as compared with the controls determined by MLC. Further studies revealed that soluble mB7h3-hIg could also inhibit IL-2 and IFN-gamma production of allogenic T cells. These results suggested a great potential of soluble B7-H3 for treatment of graft rejection and autoimmume disease.

Animals↗

PubMed2006

In silico prediction of drug solubility in water-ethanol mixtures using Jouyban-Acree model.

PURPOSE: A predictive method was proposed to predict solubility of drugs in water-ethanol mixtures at various temperatures based on the Jouyban-Acree model. The model requires the experimental solubility data of the drug in mono-solvent systems. METHODS: The accuracy of the proposed prediction method was evaluated using collected experimental solubility data from the literature. The proposed method is: log Xm,T = fc log Xc,T + fw log Xw,T + fcfw[724.21/T + 485.17(fc-fw)/T + 194.41(fc-fw)2/T] Where Xm,T, Xc,T and Xw,T are the solute solubility at temperature (T) in mixed solvent and neat cosolvent and water, respectively, fc and fw denote the solute free fraction of cosolvent (ethanol) and water. The average absolute error (AAE) of the experimental and the predicted solubilities was computed as an accuracy criterion and compared with that of a well-established log-linear model. RESULTS: The AAE (+/-SD) of the Jouyban-Acree and log-linear models were 0.19 (+/-0.13) and 0.48 (+/-0.28), respectively. The mean difference of AAEs was statistically significant (p < 0.0005) revealing that the Jouyban-Acree model was provided more accurate predictions. Although the log-linear model was used to predict solubility at a fixed temperature (25 or 23 degrees C), the results also showed that the model could be employed to predict the solubility in solvent mixtures at various temperatures. CONCLUSION: More accurate predictions were provided using the Jouyban-Acree model in comparison with a previously established log-linear model of Yalkowsky. The prediction methods were successfully extended to predict the solubility in water-ethanol mixtures at various temperatures.

Ethanol↗

PubMed1986

The soluble form of rat liver alpha-mannosidase is immunologically related to the endoplasmic reticulum membrane alpha-mannosidase.

The soluble alpha-mannosidase of rat liver, originally described as a cytoplasmic alpha-mannosidase, has been purified to homogeneity by conventional techniques. The purified enzyme has an apparent molecular weight of 350,000 and is composed of 107-kDa subunits. The soluble alpha-mannosidase has the same enzymatic properties as the endoplasmic reticulum (ER) membrane alpha-mannosidase of rat liver (Bischoff, J., and Kornfeld, R. (1983) J. Biol. Chem. 258, 7909-7910) which is believed to play a role in oligosaccharide processing in the rough ER. Like the membrane-bound ER alpha-mannosidase, the soluble alpha-mannosidase can hydrolyze alpha-linked mannose from both p-nitrophenyl alpha-mannoside (Km = 0.14 mM) and high mannose oligosaccharides, is not inhibited by the mannose analogues swainsonine and 1-deoxymannojirimycin, is stabilized by MnCl2 or CoCl2, and does not bind to concanavalin A-Sepharose. A goat polyclonal antibody raised against the purified soluble alpha-mannosidase specifically recognizes the rat liver membrane-bound ER alpha-mannosidase, leading us to propose that they are two forms of the same enzyme and that the soluble form is derived from the ER membrane alpha-mannosidase by proteolysis. The antibody also cross-reacts with both the soluble and membrane-bound forms of ER alpha-mannosidase activity in cultured Chinese hamster ovary cells and rat H35 hepatoma cells. Since the ER alpha-mannosidase is presumed to be involved in the early steps of oligosaccharide processing, the action of the purified soluble form of the enzyme on high mannose oligosaccharides was examined. Surprisingly, the enzyme released free mannose from oligosaccharides ranging in size from Glc1Man9GlcNAc to Man5GlcNAc with almost equal efficiency. However, a long term incubation of the enzyme with Man9GlcNAc led to the accumulation of Man7GlcNAc and produced only small amounts of Man6GlcNAc and Man5GlcNAc. Structural analysis of these reaction products indicated that the purified soluble form of ER alpha-mannosidase shows little specificity for which mannose residues it removes from Man9GlcNAc. In contrast, as shown in the accompanying paper, the intracellular action of ER alpha-mannosidase on glycoprotein-bound Man9GlcNAc2 is highly specific.

Animals↗

PubMed1989

Recombinant soluble Fc epsilon receptor II (Fc epsilon RII/CD23) has IgE binding activity but no B cell growth promoting activity.

We have undertaken the production of recombinant soluble Fc epsilon receptor II (Fc epsilon RII) as a secretory protein, but not as a cleavage product of membrane-bound receptor. Several plasmid constructs containing soluble receptor sequence were prepared. Only a chimeric gene containing the sequences encoding IL-6 signal peptide and the soluble moiety of Fc epsilon RII could be expressed in Xenopus laevis oocytes and CHO cells, resulting in the secretion of soluble Fc epsilon RII. The recombinant soluble Fc epsilon RII was also produced in the yeast expression system. The NH2-terminal sequence analysis of the chimeric gene product generated by oocytes demonstrated the correct cleavage of IL-6 leader sequence by a signal peptidase. Moreover, most of CHO cell and all of the yeast-derived recombinant molecules were products identical with the native B cell-derived soluble Fc epsilon RII. These recombinant products as well as the natural soluble receptor derived from a human B cell line could bind both human IgE and two different anti-Fc epsilon RII mAb and could competitively inhibit the binding of IgE to Fc epsilon RII-expressing cells. However, the recombinant soluble Fc epsilon RII and highly purified native molecules did not display any B cell growth-promoting activity.

Amino Acid Sequence↗

PubMed1979

[Solubility of metallic mercury into the solutions containing various amino acids (author's transl)].

The solubility of metallic mercury in water containing various amino acids were investigated with flameless atomic absorption spectrometry. The following results were obtained; 1. Metallic mercury dissolved into aqueous solutions of various amino acids. It was found that solubility was dependent on kind and concentration of the amino acids. The amino acid with SH radicals, i.e., L-cysteine HCl, in particular, remarkably accelerated solubility. 2. The pH value gave large effects on solubility of metallic mercury. The least solubility was observed at neutral range. Solubility was, however, increased above or below the neutral range. 3. The solubility was greater in Hanks' balanced salt solution than in distilled water. The present results confirmed that solubility of metallic mercury in various solutions was largely dependent on the presence of amino acids, in particular, those which contained SH radicals, change of pH and presence of various salts.

Amino Acids↗

PubMed1985

A water-soluble form of porin from the mitochondrial outer membrane of Neurospora crassa. Properties and relationship to the biosynthetic precursor form.

Mitochondrial porin, the outer membrane pore-forming protein, was isolated in the presence of detergents and converted into a water-soluble form. This water-soluble porin existed under nondenaturing conditions as a mixture of dimers and oligomers. The proportion of dimers increased with decreasing porin concentration during conversion. Water-soluble porin inserted spontaneously into artificial bilayers as did detergent-solubilized porin. Whereas the latter form had no specific requirements for the lipid composition of the bilayer, water-soluble porin inserted only into membranes containing a sterol, and only in the presence of very low concentrations of Triton X-100 (0.001% w/v) in the solution bathing the bilayer. The channels formed by water-soluble porin were indistinguishable from those formed by detergent-purified porin with respect to specific conductance and voltage dependence of conductance. Water-soluble porin bound tightly in a saturable fashion to isolated mitochondria. The bound form was readily accessible to added protease, indicating its presence on the mitochondrial surface. The number of binding sites was in the range of 5-10 pmol/mg of mitochondrial protein. Water-soluble porin apparently binds to a site on the assembly pathway of the porin precursor, since mitochondria whose binding sites were saturated with the water-soluble form did not import porin precursor synthesized in a cell-free system.

Bacterial Outer Membrane Proteins↗

PubMed1987

Calcium and phosphate solubility in neonatal parenteral nutrient solutions containing Aminosyn PF.

Factors affecting the solubility of calcium and phosphate in neonatal total parenteral nutrient (TPN) solutions containing a new amino acid formulation were studied. Six TPN solutions containing various concentrations of Aminosyn PF, an amino acid solution for infants and children, were prepared in 10% dextrose injection. Some of the solutions also contained cysteine hydrochloride 40 mg per gram of protein. Various concentrations of calcium gluconate and monobasic and dibasic potassium phosphate were added to 20-mL samples of the TPN solutions. A total of 27 samples of each TPN solution was prepared. Samples were visually inspected after 18 hours at 25 degrees C and again after 30 minutes in a water bath at 37 degrees C. Clear samples at this time were also examined microscopically. Solubility curves were prepared by plotting the concentrations at which either visual or microscopic precipitation occurred. Solubility curves for TPN formulations containing Aminosyn PF revealed a decrease in calcium solubility of 5 to 15 meq/L and a decrease in phosphate solubility of 5 to 15 mmol/L compared with previously published calcium-phosphate solubility curves for another similar amino acid solution, TrophAmine. Calcium and phosphate solubilities were also influenced by temperature and the time after solution preparation. In these TPN formulations containing Aminosyn PF as the amino acid source, the solubilities of calcium and phosphate were substantially less than reported in a previous study of solutions containing TrophAmine.

Amino Acids↗