Evaluating the Acceptability, Swallowability, and Palatability of Film-Coated Mini-Tablet Formulation in Young Children: Results from an Open-Label, Single-Dose, Cross-Over Study

Mini-tablets are advantageous over liquid formulations in overcoming challenges related to stability, taste, and dosage. This open-label, single-dose, cross-over study investigated the acceptability and safety of drug-free, film-coated mini-tablets in children aged 1 month-6 years (stratified: 4-6 years, 2-<4 years, 1-<2 years, 6-<12 months, and 1-<6 months), and their preference for swallowing either a high quantity of 2.0 mm or a low quantity of 2.5 mm diameter mini-tablets. The primary endpoint was acceptability derived from swallowability. The secondary endpoints were investigator-observed palatability, acceptability as a composite endpoint derived from both swallowability and palatability, and safety. Of 320 children randomized, 319 completed the study. Across all tablet sizes, quantities and age groups, acceptability rates based on swallowability were high (at least 87%). Palatability was rated as "pleasant/neutral" in 96.6% of children. The acceptability rates as per the composite endpoint were at least 77% and 86% for the 2.0 mm and 2.5 mm film-coated mini-tablets, respectively. No adverse events or deaths were reported. Recruitment in the 1-<6-months group was stopped early due to coughing-evaluated as "choked on" in three children. Both 2.0 mm and 2.5 mm film-coated mini-tablets are suitable formulations for young children.

Phenotypic screen identifies calcineurin-sparing FK506 analogs as BMP potentiators for treatment of acute kidney injury

Acute kidney injury (AKI) is a life-threatening disease with no known curative or preventive therapies. Data from multiple animal models and human studies have linked dysregulation of bone morphogenetic protein (BMP) signaling to AKI. Small molecules that potentiate endogenous BMP signaling should have a beneficial effect in AKI. We performed a high-throughput phenotypic screen and identified a series of FK506 analogs that act as potent BMP potentiators by sequestering FKBP12 from BMP type I receptors. We further showed that calcineurin inhibition was not required for this activity. We identified a calcineurin-sparing FK506 analog oxtFK through late-stage functionalization and structure-guided design. OxtFK demonstrated an improved safety profile in vivo relative to FK506. OxtFK stimulated BMP signaling in vitro and in vivo and protected the kidneys in an AKI mouse model, making it a promising candidate for future development as a first-in-class therapeutic for diseases with dysregulated BMP signaling.

Prognostic value of tyrosinase reverse-transcriptase polymerase chain reaction in metastatic melanoma

BACKGROUND

Circulating tumor cells can now be identified in subjects with metastatic melanoma by using the reverse-transcriptase polymerase chain reaction (RT-PCR) to detect the messenger RNA of tyrosinase, a key enzyme of melanogenesis.

AIM AND METHODS

The aim of this study was to determine whether the detection of positive tyrosinase cells in patients at metastatic stage was associated with a worse evolution. 32 patients were included with metastatic melanoma (AJCC IV).

RESULTS

66% had a positive tyrosinase RT-PCR and a shorter survival compared with patients with a negative RT-PCR, but this difference is not statistically significant. However, a positive test could appear indicative of rapid progression and poor prognosis.

CONCLUSION

The prognostic value of this method could be improved by combining it with PCR of other melanoma markers (Melan A, Mage 3) or assays of serum markers (S 100 protein or lactate dehydrogenase).

Epitope mapping of four novel CD44 monoclonal antibodies using surface plasmon resonance and soluble CD44

CD44 is a ubiquitous multistructural and multifunctional cell surface adhesion molecule. The molecular diversity of this glycoprotein is generated by both post-translational modification and the differential use of alternatively spliced exons which play a critical role in determining the exact conformation of the molecule. CD44 isoforms are found in many tissues and in soluble form in plasma. Soluble CD44 was purified by a two-step purification combining ion exchange and immuno-affinity chromatography. Our aim was to check that all the known antigenic epitopes are present on sCD44, which could thus be used for the mapping of new anti-CD44 antibodies. Competitive binding assays using reference antibodies and novel anti-CD44 monoclonal antibodies were performed by real-time biospecific interaction analysis. Reference mAbs identified on soluble CD44 the three distinct epitopes previously defined using red blood cell membrane CD44. From the four novel CD44 mAbs, two mAbs (NaM198-6B5, NaM198-10B4) mapped to epitope group 1, whereas the others (NaM10-8F4, NaM77-9D6) mapped to epitope group 2. Immunopurified sCD44 obtained from the plasma of healthy donors appears to be a usable tool for the mapping of anti-CD44 mAbs.

Overexpression of the CD155 gene in human colorectal carcinoma

BACKGROUND AND AIMS

The Tage4 gene (tumour associated glycoprotein E4) is overexpressed in rat colon tumours and Min mouse intestinal adenomas. The rat Tage4 protein has approximately 40% identity with human CD155, a member of the immunoglobulin superfamily coding for a transmembrane protein capable of serving as an entry receptor for poliovirus, porcine pseudorabies virus, and bovine herpesvirus 1. Analysis of the rat Tage4 gene has revealed structural and functional similarities with the human CD155 gene. We therefore investigated expression of the CD155 gene in human colorectal carcinomas.

METHODS

Overall CD155 expression was assessed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical analysis using tissue specimens from patients with colorectal adenomas and adenocarcinomas. We also used a qualitative RT-PCR assay to determine relative expression of different splicing variants in each sample.

RESULTS

mRNA levels of CD155 were increased in six of six colorectal cancer tissues compared with the tumour free colon mucosa. Immunohistochemical analysis revealed an increased level of CD155 protein in 12 of 12 samples. The qualitative RT-PCR assay revealed that relative expression of the different CD155 variant transcripts was similar in the different normal and cancer samples tested, indicating that this overexpression is not associated with a particular mRNA variant generated by alternative splicing of the CD155 gene.

CONCLUSION

We have shown for the first time that the CD155 gene is overexpressed in colorectal carcinoma and that this overexpression begins at an early stage in tumorigenesis and continues to late stages.

Organization of the rat Tage4 gene and herpesvirus entry activity of the encoded protein

The Tage4 gene (Tumor-Associated Glycoprotein E4) is a member of the immunoglobulin superfamily overexpressed in rat colon tumors and Min mouse intestinal adenomas. The Tage4 cDNA presents approximately 60% identity with the human CD155, a member of the immunoglobulin superfamily coding for a transmembrane protein capable of serving as an entry receptor for poliovirus, porcine pseudorabies virus and bovine herpesvirus 1. We determined the structure of the Tage4 gene. This gene covers approximately 15 kb and is composed of eight exons and seven introns. We also isolated approximately 2 kb of the 5' flanking region of the Tage4 gene and demonstrated the existence of closely clustered transcription start sites. No splicing variant was identified by RT-PCR indicating that the Tage4 gene is transcribed as a unique mRNA. Finally, the protein encoded by the Tage4 gene was tested for ability to mediate entry of several viruses. These structural and functional features of the rat Tage4 gene were compared to those of the human CD155 gene. The results indicated that the Tage4 gene is probably orthologous to the gene for CD155.

Limitations of CD44v6 amplification for the detection of tumour cells in the blood of colorectal cancer patients

Based on the important role of CD44 splice variants in colorectal cancer progression and metastasis, we evaluated the use of CD44v6 expression to detect and assess the metastatic potential of colorectal tumour cells circulating in peripheral blood. A nested amplification was designed that allowed to detect 10-100 colon cancer cells. This assay was applied to blood samples from healthy donors. Strong signals were detected in all cases, indicating that it cannot be used to detect colorectal carcinoma cells in whole blood. We then included an enrichment step based on the use of an anti-epithelial cells monoclonal antibody (BerEP4) coupled to magnetic beads. The CD44v6 reverse transcription polymerase chain reaction (RT PCR) assay was performed on cDNA synthesized from blood samples treated with these beads. We analysed 18 samples from 12 patients with a gastrointestinal disease, and 36 samples from ten patients with a colorectal cancer. None of the patients used as negative controls were found to contain epithelial cells in their blood as determined by cytokeratin 19 RT-PCR. By contrast, CD44 transcripts containing exon v6 were detected in nine out of the 18 samples tested (50%). For the colorectal cancer patients, six out of the seven samples (85.7%) that were cytokeratin 19-positive were CD44v6-negative, whereas ten samples out of the 29 not containing epithelial cells were CD44v6-positive (34.5%). This is probably due to the persistence of CD8+ leucocytes in the enriched preparations, as determined by PCR analysis of the CD8 alpha-chain. We conclude that detection of CD44v6 transcripts using a sensitive nested RT-PCR assay has no potential value to detect and characterize colorectal cancer micrometastases from blood, even following an initial enrichment step.

Soluble CD44: quantification and molecular repartition in plasma of patients with colorectal cancer

Based on the important role of CD44 in tumour progression and metastasis, we evaluated, in a prospective study, plasma-soluble CD44 (sCD44) as a serum marker in colorectal cancer. Blood plasma specimens from 89 patients with colorectal neoplasm, 22 patients with a gastrointestinal disease and 23 healthy donors were analysed for quantitation (ELISA assay) and purification of sCD44. The concentration of sCD44, indicating the concentration of all isoforms, was significantly higher in patients with colorectal cancer and intestinal disease than in normal individuals, but no significant differences were found between the two groups. We found no association between plasma levels and staging of the colorectal cancer patients according to Astler and Coller. A two-step batch purification combining ion exchange and immunoaffinity chromatography, followed by Western blot analysis, revealed a complex pattern with a major band corresponding to the standard form of CD44 and minor bands that may correspond to larger variant forms. No particular sCD44 isoform was clearly associated with anatomopathological or biological information.

[Detection of circulating neoplastic cells by reverse transcriptase and polymerase chain reaction in melanoma]

BACKGROUND

Circulating melanocytes can be detected in peripheral blood of patients with malignant melanoma by means of tyrosinase messenger RNA amplification. In this study we especially examined peripheral blood from patients with stage II melanoma before and after lymph node dissection for the detection of these circulating melanoma cells. Indeed the presence of regional nodal metastasis is one of the most important prognostic factors in patients with cutaneous melanoma.

PATIENTS AND METHODS

Blood samples were collected from 20 normal patients, 42 patients with stage I melanoma and 23 patients with stage III melanoma. Twenty patients with stage II melanoma were tested 3 days before lymph node dissection and 2 à 8 weeks after. To identify circulating melanocytes, we used coupled reverse-transcription and polymerase chain reaction to target tyrosinase messenger RNA.

RESULTS

None of the 20 patients with stage II melanoma had detectable circulating melanocytes before lymph node dissection. By contrast, 7 of them became transiently PCR positive in the 8 weeks following surgery. We observed no evidence of correlation between the presence of circulating melanocytes after lymph node dissection and the risk of relapse within 6 months after surgery or the presence of capsule breaking or the number of involved lymph nodes. Sixty-nine percent of stage III patients and none of stage I patients were found to have circulating melanocytes.

DISCUSSION

Our study suggests that melanoma cells could circulate transiently after lymph node dissection. Confrontation of our results with literature data, despite important discrepancies related in part to sensibility technique, shows that the presence of circulating melanoma cells is correlated to the clinical stage. Prognostic value of these circulating cells need to be further assessed by prospective studies with large number of patients and long follow-up.

Detection of disseminated tumor cells in peripheral blood of colorectal cancer patients

All cancer staging systems seek to identify clinical and pathological features that can predict outcome or guide therapy. In particular, a non-invasive method for the early detection of disseminating disease would be of great interest. We investigated the use of cytokeratin genes expression to detect blood metastases from colorectal tumors. Epithelial tumor cells were isolated from whole blood using the monoclonal antibody (MAb) BerEP4 and magnetic beads, and detected by reverse transcription-polymerase chain reaction using oligonucleotides derived from the cDNA sequences of cytokeratins 8, 19 and 20. The sensitivity of this assay was determined by spiking SW620 colon carcinoma cells in normal blood. Using cytokeratin 19 expression we were able to detect 1 epithelial tumor cell in 1 ml of whole blood. The clinical applicability of this technique was explored by evaluating patients with a colorectal carcinoma. Epithelial cells were detected in the blood of 12 out of 23 patients, 2 (20%) of 10 with Astler-Coller stage A or B, and 10 (77%) of 13 with stage C or D cancer. In conclusion, this test is a non-invasive, sensitive, and specific assay for detecting circulating epithelial cells in blood. It may be useful for the early diagnosis of disseminating disease, to determine whether the presence of micrometastatic cells at the time of surgery is correlated with an early relapse and for monitoring adjuvant therapeutic trials.

H blood group antigen carried by CD44V modulates tumorigenicity of rat colon carcinoma cells

Expression of carbohydrate ABH blood group antigens is oncodevelopmentally regulated and their presence on tumor cells constitutes a prognostic factor. However, it is not clear whether they directly affect tumor behavior. Using a rat model of colon carcinoma, we previously observed an association between the presence of H blood group antigens and tumorigenicity in syngeneic animals. In the present study, we show by immunoprecipitation experiments that cell surface H blood group antigens of a highly tumorigenic clone (PROb) are essentially carried by splice variants of the CD44 molecule containing exon V6. PROb cells were then transfected with an antisense fragment of the gene coding for a rat alpha (1-2)fucosyltransferase. This enzyme allows synthesis of H antigens from various beta-galactoside precursors. Transfected subclones of PROb cells were obtained which had significantly decreased enzymatic activity and H antigenic cell surface levels. In contrast, no such changes were observed in control cells transfected with either the empty vector or with a sense fragment of the gene. Compared to controls, the antisense-transfected cells were far less tumorigenic in syngeneic animals. These results show that H blood group antigens at the surface of PROb colon carcinoma cells contribute to tumor progression. The presence of the fucosylated structures on CD44 could modulate the functions of this adhesion molecule.

Over-expression of the S13 ribosomal protein in actively growing cells

In order to define biological markers of aggressiveness, 2 rat colon-carcinoma cell lines differing by their tumorigenicity were used to clone genes over-expressed in colon carcinoma as compared with normal epithelial cells. A progressive rat colon-carcinoma clone (PROb) cDNA library was hybridized with 32P-cDNA synthesized from mRNA prepared from these PROb cells, or from regressive cells (REGb) derived from the same tumor. Several clones were isolated after the initial screening. The specificity of each clone was confirmed by RNA blotting. One of these (B9) was found to hybridize to an mRNA 30-fold more abundant in PROb cells than in normal adult rat colon, and was therefore selected for further study. No gene amplification was detected by Southern blot analysis, indicating that the difference in mRNA content was most likely due to an increased transcription of this gene. Sequencing of the cDNA revealed approximately 98% homology with the rat S13 ribosomal protein. The expression level of this gene was determined in a series of rat cell lines with different growth rates. A good correlation was found between these 2 parameters. Our data suggest that the S13 ribosomal-protein gene can be used to evaluate the growth rate of tumor cells, which might be correlated with their aggressiveness. In an initial trial experiment, S13 ribosomal-protein mRNA was detected in a series of human colorectal tumors by in situ hybridization. A strong signal was seen in the 4 tumors analyzed.

Retinoic acid modulation of alpha(1-->2) fucosyltransferase activity and sensitivity of tumor cells to LAK-mediated cytotoxicity

We examined the effects of all-trans retinoic acid (RA) on alpha(1-->2) fucosyltransferase activity and sensitivity to LAK-mediated cytotoxicity in two rat colon carcinoma cell lines differing by their glycosylation state and their tumorigenic potential. RA induced a decrease in alpha(1-->2) fucosyltransferase activity in the more tumorigenic variant PROb. Fucosyltransferase mRNA levels were not affected by RA treatment in PROb cells, suggesting a posttranscriptional control. This inhibition was accompanied by a decreased expression of fucosylated membrane glycoconjugates and by a significant increase in the sensitivity to LAK-mediated cytotoxicity. REGb cells, which exhibited a very low enzymatic activity and very few fucosylated glycoconjugates, were more sensitive to LAK-lysis than PROb cells and were not affected by RA treatment.

Simple and Sensitive Determination of Urea in Serum and Urine

In this method for serum and urinary urea determination, the same reagent is used without predilution of urine samples. The method is based on the pH increase resulting from the ammonia released by urease hydrolysis of urea. o-Cresolphthalein complexone is used to monitor the pH change colorimetrically. Urea concentration and absorbance at 570 nm are linearly related for concentrations as great as 600 mmol/L for urine samples and 100 mmol/L for serum. There are no clinically significant interferences from physiological substances or drugs, and precision and accuracy are excellent (CV approximately 2%, except at very low concentrations in serum; analytical recovery was 99% in urine, 100% in serum). Results by this method (y) and by the Astra method (x) for urine correlated well (y = 0.991x - 2.87, Sy/x = 9.21, r = 0.994), as did the results by this method and by the total enzymatic method (x') for serum (y = 1.002x' + 0.192, Sy/x' = 0.598, r = 0.997). This method is applicable to automated as well as manual instruments, and one-reagent or two-reagent formats can be used.

Simple and sensitive determination of urea in serum and urine

In this method for serum and urinary urea determination, the same reagent is used without predilution of urine samples. The method is based on the pH increase resulting from the ammonia released by urease hydrolysis of urea. o-Cresolphthalein complexone is used to monitor the pH change colorimetrically. Urea concentration and absorbance at 570 nm are linearly related for concentrations as great as 600 mmol/L for urine samples and 100 mmol/L for serum. There are no clinically significant interferences from physiological substances or drugs, and precision and accuracy are excellent (CV approximately 2%, except at very low concentrations in serum; analytical recovery was 99% in urine, 100% in serum). Results by this method (y) and by the Astra method (x) for urine correlated well (y = 0.991x - 2.87, Sy/x = 9.21, r = 0.994), as did the results by this method and by the total enzymatic method (x') for serum (y = 1.002x' + 0.192, Sy/x' = 0.598, r = 0.997). This method is applicable to automated as well as manual instruments, and one-reagent or two-reagent formats can be used.

Isolation of cDNA clones corresponding to genes differentially expressed in two colon-carcinoma cell lines differing by their tumorigenicity

In an effort to isolate genes involved in the progression of colonic cells leading to a carcinoma, we used as a model 2 rat colon-carcinoma cell lines selected from the same tumor, differing by their tumorigenicity. When soluble, Triton-X-100 extracted, or cytoskeletal proteins from the progressive PROb cells and the regressive REGb cells were analyzed by SDS-PAGE, minor differences were seen. Furthermore, mRNA-cDNA hybridization analyses showed extensive homology between the 2 mRNA populations. Thus, the homology between the 2 clones is high at both the protein and the mRNA levels. A PROb cDNA library was hybridized with 32P-cDNA synthesized from PROb or REGb mRNA. The clones giving a stronger signal when hybridized with the homologous PROb probe were isolated. The specificity of each clone was confirmed by RNA blotting. Most of the positive clones showed a 2- to 3-fold higher expression in PROb cells when compared with REGb cells. One clone (J 13) corresponded to an mRNA 7- to 10-fold more abundant in PROb cells, and was further studied. No gene amplification was detected by Southern blot analysis, indicating that the difference in mRNA content was most likely due to an increased transcription of this gene in PROb cells. Sequencing of the cDNA showed high homology with the rat ferritin light sub-unit. Over-expression of ferritin in PROb cells as compared with REGb cells was confirmed at the protein level using specific antibodies.

Biological effects of glucocorticoid hormones on two rat colon adenocarcinoma cell lines

Glucocorticoid hormones are thought to play a role in carcinogenesis as they regulate cell differentiation and proliferation. We have investigated the effect of dexamethasone on two cell lines derived from a colon carcinoma, which differ by their tumorigenicity. Dexamethasone was found to inhibit growth of both the progressive (PROb) and the regressive clone (REGb). Upon glucocorticoid treatment, PROb cells were found to secrete an additional Mr approximately 40,000 protein. The synthesis and the release in the culture medium of this protein is stimulated specifically by glucocorticoid agonists, and not by other steroid hormones. The anti-glucocorticoid RU 38486 is inefficient and suppresses the induction of this protein by dexamethasone. Induction is sensitive to actinomycin D, suggesting that regulation may be related to an alteration of the rate of mRNA synthesis. The cellular effect of glucocorticoid hormones being mediated through a specific soluble receptor, we have characterized this protein. The PROb cells contained more specific glucocorticoid-binding sites (approximately 170,000 sites per cell) than the regressive ones (REGb cells; approximately 100,000 sites per cell). In both clones, the receptor was associated with the Mr approximately 90,000 heat shock protein to yield large complexes (Stokes radius Rs approximately 7.5 nm), which were dissociated to the same extent upon heat- and salt-treatment. The steroid- and DNA-binding unit of the receptor, characterized under denaturing conditions using an anti-receptor monoclonal antibody, was found to be more degraded in the PROb cell line.

A secreted Mr approximately 40,000 glycoprotein specifically induced by glucocorticoids in a rat colon carcinoma cell line

Glucocorticoid hormones are thought to play a role in carcinogenesis, as they regulate cell differentiation and proliferation. We have previously shown that dexamethasone inhibits the growth of a rat colon carcinoma cell line, and induces the secretion of an Mr approximately 40,000 protein. We now report that the synthesis and the release in the culture medium of this protein is stimulated specifically by glucocorticoid agonists, and not by other steroid hormones. The anti-glucocorticoid RU 38486 is inefficient and suppresses the induction of this protein by dexamethasone. Induction is sensitive to actinomycin D, suggesting that regulation may be exerted by altering the rate of mRNA synthesis. Characterization of culture medium from dexamethasone-treated cells revealed that the Mr approximately 40,000 protein is glycosylated, and can be further separated from other secreted proteins by high-performance anion-exchange chromatography.

Glucocorticoid effects and receptors in two rat colon carcinoma cell lines differing by their tumorigenicity

Steroid hormones, regulators of cell differentiation and proliferation, are believed to play a role in carcinogenesis. Glucocorticoid hormones in particular modulate the expression of a number of proteins implicated in this process. We have investigated the effect of dexamethasone on two cell lines derived from a colon carcinoma, which differ by their tumorigenicity. Dexamethasone was found to inhibit growth of both the progressive (PROb) and the regressive clone (REGb). Upon hormonal treatment, glucocorticoid hormones induced fibronectin secretion by the two clones, whereas PROb cells were found to secrete an additional Mr approximately 43,000 protein. The cellular effect of glucocorticoid hormones being mediated through a specific soluble receptor, we have characterized this protein. The progressive cells (PROb) contained more specific glucocorticoid-binding sites (approximately 170,000 sites per cell) than the regressive ones (REGb cells; approximately 100,000 sites per cell). In both clones, the receptor was associated with the Mr approximately 90,000 heat shock protein to yield large complexes (Stokes radius Rs approximately 7.5 nm), which were dissociated to the same extent upon heat- and salt-treatment. The steroid- and DNA-binding unit of the receptor, characterized under denaturing conditions using an anti-receptor monoclonal antibody was found to be more degraded in the progressive cell line.

Reaction of tyrosyl-modifying reagents with the ligand- and DNA-binding domains of the rabbit liver glucocorticoid receptor

We have studied the effects of p-nitrobenzenesulfonyl fluoride, 4-fluorosulfonyl-1-hydroxy-2-naphtoic acid, 7-chloro-4-nitrobenz-2-oxa-1,3-diazole and tetranitromethane on the glucocorticoid receptor from rabbit liver. Our results show that all tyrosine modifying reagents inhibit the binding of [3H]dexamethasone to the receptor. Equilibrium binding experiments revealed that only 4-fluorosulfonyl-1-hydroxy-2-naphtoic acid is a competitive inhibitor while the other chemical probes decrease the concentration of binding sites. Transformation of glucocorticoid-receptor complexes was markedly reduced when heat treatment was performed in the presence of tyrosyl-directed reagents. Taken together, these results indicate for the first time that critical tyrosyl moieties may be involved in both hormone binding and transformation of the glucocorticoid receptor.

One-step 10(4)-fold purification of transformed glucocorticoid receptor. Method for purifying receptors associated with Mr ca. 90,000 heat-shock protein

Chromatography of rabbit glucocorticoid-receptor complexes in the absence of sodium molybdate on a Mono Q anion-exchange column induces the transformation of the receptor and allows the resolution of the transformed and non-transformed molecular species. These abilities were used to design a new purification scheme for the glucocorticoid receptor from rabbit liver in its transformed state. Microgram amounts of receptor were obtained using this single-step procedure in less than 2 h. The purification yield was 50-60%. Immunoblot experiments showed that the glucocorticoid receptor was present as an Mr approximately 94,000 polypeptide in these preparations and represented 20-30% of the eluted proteins as determined by densitometric scanning analysis of silver-stained sodium dodecyl sulphate polyacrylamide gels. Finally, the purified receptor was able to interact quantitatively with bulk DNA.

An improved pyrogallol red-molybdate method for determining total urinary protein

We adapted the pyrogallol red-molybdate method for total urinary protein to the Cobas Bio centrifugal analyzer. The method is simple, rapid, sensitive, and inexpensive. Addition of 25 mg of sodium dodecyl sulfate per liter to the reagent modifies protein reactivities so that the chromogenicity of human gamma globulins is the same as that of albumin. Results by this method and a comparison method that included gel filtration and a modified biuret reaction correlated well (r = 0.951).

An improved pyrogallol red-molybdate method for determining total urinary protein

We adapted the pyrogallol red-molybdate method for total urinary protein to the Cobas Bio centrifugal analyzer. The method is simple, rapid, sensitive, and inexpensive. Addition of 25 mg of sodium dodecyl sulfate per liter to the reagent modifies protein reactivities so that the chromogenicity of human gamma globulins is the same as that of albumin. Results by this method and a comparison method that included gel filtration and a modified biuret reaction correlated well (r = 0.951).

Improvement in glucocorticoid receptor binding affinity concomitant to shift from antagonist to agonist activity in a series of 17 beta-carboxamide derivatives of dexamethasone

Modification of the 17 beta-side chain of the synthetic glucocorticoid agonist dexamethasone by periodic oxidation and subsequent coupling to various primary amines yield secondary 17 beta-carboxamide derivatives displaying antiglucocorticoid activity in vitro, but not in vivo. To obtain more potent antiglucocorticoids, new secondary and tertiary 17 beta-carboxamide derivatives were synthesized. Although they displayed an improved affinity for the glucocorticoid receptor in rat thymus cytosol and antiglucocorticoid activity in rat hepatoma (HTC) cells, these new compounds were again devoid of in vivo antiglucocorticoid activity in the rat. Moreover, the increase in receptor binding affinity was correlated for most compounds with the appearance of a partial agonist activity in HTC cells. The tertiary 17 beta-carboxamide derivative DX diMe displayed the highest affinity but was also a partial agonist in vivo. Kinetic studies with several tritiated 17 beta-carboxamide derivatives showed that they had association rate constants similar to that of dexamethasone, but different dissociation rate constants. The rapid dissociation of the compounds displaying antiglucocorticoid activity contrasted with the slow dissociation of DX diMe. Therefore, antiglucocorticoid activity in the 17 beta-carboxamide series is probably related to the formation of rapidly dissociating glucocorticoid receptor-ligand complexes that are unable to undergo the transformation step.

Occurrence of glucocorticoid binding sites in solubilized microsomes from rat liver

Recent studies suggested the presence of specific glucocorticoid binding sites on rat liver microsomal membranes. We report here a new solubilization procedure which allows the physicochemical characterization of the microsomal glucocorticoid binding sites. Solubilization was achieved with 2 mM CHAPS in the presence of 5 mM benzamidine. Binding of [3H]cortisol showed a high affinity (Kd = 5.1 x 10(-9) M) and a limited capacity (0.72 pmol/mg of protein). The binding activity was abolished by elevated temperature and pronase. Competition experiments revealed that natural glucocorticoids and progesterone were highly potent competitors whereas dexamethasone and triamcinolone acetonide did not compete. Chromatography on DEAE Trisacryl and heparin Ultrogel confirmed that the solubilized protein is different from corticosteroid binding globulin and the cytosolic glucocorticoid receptor. Treatment of microsomal fractions with phosphatidyl inositol phospholipase C promoted the release of specific binding activity suggesting a putative glycosylphosphatidyl anchor for this protein. This finding may have interesting implications concerning the mechanism of glucocorticoid hormone action.

Application of high-performance ion-exchange chromatography to the analysis of cytosolic glucocorticoid receptor

The use of high-performance ion-exchange chromatography (HPIEC) on a Mono Q column was investigated for the analysis of glucocorticoid receptor. In the presence of 10 mM sodium molybdate, both liganded and unliganded glucocorticoid receptor were eluted as a single and sharp peak (0.32 M NaCl). In the absence of molybdate and after exposure to heat and salt, another peak of specifically bound radioactivity was eluted with 0.08 M NaCl. When HPIEC was performed in the absence of molybdate, two molecular forms of the liganded receptor were detected which eluted with 0.08 M NaCl (Stokes' radius Rs = 5.1 nm, s20,w = 4.6 S, calculated mol. wt Mr approximately 100,000) and 0.32 M NaCl (Rs = 7.3 nm, S20,w = 9.0 S, calculated Mr approximately 280,000). Analysis of both forms with mini-columns of DNA-Ultrogel, DEAE-Trisacryl and hydroxylapatite (HA-Ultrogel) confirmed the identity of the two peaks with transformed and non-transformed glucocorticoid-receptor complexes. These results suggest that HPIEC may provide a useful tool for the rapid resolution and quantification of receptor molecular forms.

A new affinity matrix for mineralocorticoid receptors

The behavior of mineralocorticoid and glucocorticoid receptors of rabbit kidney cytosol was investigated on two affinity gels: a new affinity matrix prepared with a 3-O-derivative of carboxymethyloxime deoxycorticosterone (deoxycorticosterone gel) and a gel linked to a 17 beta-dexamethasone derivative (dexamethasone gel). Deoxycorticosterone gel was highly specific, since it retained mineralocorticoid but not glucocorticoid receptors, and dexamethasone gel exhibited high selectivity for glucocorticoid receptors since it did not bind mineralocorticoid receptors. The use of these two matrices allowed separation of mineralocorticoid and glucocorticoid receptors and further characterization of each type of cytosolic receptors after its isolation. Cytosolic mineralocorticoid and glucocorticoid receptors stabilized by tungstate were found to have a Stokes radius of approximately 6 nm, as determined by high performance size exclusion chromatography and a sedimentation coefficient of approximately 9 S, determined on a glycerol density gradient containing tungstate, under either high or low salt conditions. The hydrodynamic parameters, binding characteristics, and specificity of mineralocorticoid receptors were the same in the untreated and dexamethasone gel-treated cytosol. Similarly glucocorticoid receptor characteristics remained unchanged after deoxycorticosterone gel treatment, indicating biochemical independence of cytosolic mineralocorticoid and glucocorticoid receptors. The [3H]aldosterone receptor complex eluted from deoxycorticosterone gel was recovered with a 30-40% yield and a purification factor of about 1000. Purified mineralocorticoid receptors had the same sedimentation coefficient as cytosolic mineralocorticoid receptors (9 S) but a different Stokes radius (4 versus 6 nm). The decrease in the Stokes radius of the purified mineralocorticoid receptors was probably due to the gel filtration method. These results indicate that the newly synthesized matrix specific for mineralocorticoid receptors constitutes a powerful tool for their extensive purification.

Affinity of corticosteroids for mineralocorticoid and glucocorticoid receptors of the rabbit kidney: effect of steroid substitution

Corticosteroid derivatives coupled in the C3, C7 or C17 position with a long aliphatic chain were synthesized in order to select a suitable ligand for the preparation of a biospecific affinity adsorbent for mineralocorticoid receptor purification. The affinity of these derivatives for mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) was explored in rabbit kidney cytosol. In this model, aldosterone bound to a single class of receptors with high affinity (Kd 1 nM) and mineralocorticoid specificity. RU26988, a highly specific ligand for GR, did not compete for these sites. The C7 and C17 positions were found to be of crucial importance in the steroid's interaction with the mineralocorticoid receptors, since the linkage of a long side chain in these positions induced complete loss of affinity. Hence, deoxycorticosterone no longer bound to MR after 17 beta substitution with a 9-carbon aliphatic chain. This loss of affinity was not observed for glucocorticoids. The 17 beta nonylamide derivative of dexamethasone still competed for GR. Increasing the length of the C7 side of the spirolactone SC26304 suppressed its affinity for MR. Finally, C3 was an appropriate position for steroid substitution. The 3-nonylamide of carboxymethyloxime deoxycorticosterone bound to MR but not to GR, and therefore constitutes a suitable ligand for the preparation of a mineralocorticoid adsorbent.

Interaction of rat liver glucocorticoid receptor with lectins: is the glucocorticoid receptor a glycoprotein?

Although glucocorticoid receptors have been extensively studied in a variety of tissues, the precise nature of the receptor protein still remains unknown. To further characterize this protein we assessed the effects of various lectins on [3H]dexamethasone binding to prepurified preparations of rat liver glucocorticoid receptor. Among the lectins tested only Ulex europeus and Lens culinaris induced a concentration-related decrease in [3H]dexamethasone binding. Following Ulex europeus or Lens culinaris exposure Scatchard analysis showed that these lectins led to a 3-fold reduction in receptor affinity without influencing the concentration of binding sites. These results provide new experimental evidence that rat liver glucocorticoid receptor would possess alpha-L-fucosyl and alpha-D-mannopyranoside residues in close proximity to the glucocorticoid receptor binding domain.

Nontransformed rabbit liver glucocorticoid receptor: purification, characterization and transformation

The molybdate-stabilized nontransformed form of the glucocorticoid receptor from rabbit liver has been purified approximately 8,000-fold by a three-step procedure. The first step involved protamine sulfate precipitation which allowed a 5-6-fold purification with 85% yield. The second step, affinity chromatography using a N-(12-dodecyl-amino) 9 alpha-fluoro-16 alpha-methyl-11 beta, 17 alpha-dihydroxy-3-oxo-1,4-androstadiene-17 beta-carboxamide substituted Sepharose gel, purified the receptor 1,500-2,000-fold as calculated by specific radioactivity. The third step involved high performance liquid chromatography resulting in overall purification near 8,000-fold. The final glucocorticoid receptor appeared about 60% pure. The purified nontransformed glucocorticoid receptor had a sedimentation coefficient of 9 S in 0.16 M phosphate containing 5-20% sucrose gradients and the Stokes radius was 6.1-6.3 nm as determined by low pressure gel filtration and HPLC. Binding specificity of the purified receptor was identical to that previously reported in crude rabbit liver cytosol. Isoelectricfocusing and ion-exchange chromatography showed that the purification procedure affected the net charge of the receptor protein. This phenomenon could be related to interactions between the glucocorticoid receptor and cytosolic factors. SDS polyacrylamide gel electrophoresis showed a major Mr = 94,000 protein band which is in good agreement with previously reported values for glucocorticoid receptors. Transformation of the purified receptor was achieved after removal of molybdate by exposure at 25 degrees C to 0.4 M KCl. Characterization of the molecular forms was performed by means of incorporation into isolated nuclei, affinity towards polyanionic exchangers and high pressure size exclusion chromatography. Results show that about 40% of the receptor is in the transformed state.