Phase transfer catalyzed synthesis of 4-nitrophenyl 1-thio-beta-D-glycobiosides.
Explore the source record for details and available documents.
Carbohydrate Sequence↗
Biomedical subjects
R Roy
Publications and source records attributed to R Roy.
Human myoblast transplantation: preliminary results of 4 cases.
Myoblasts from immunocompatible donors have been transplanted into the muscles (tibialis anterior, biceps brachii, and/or extensor carpi radialis longus) of 4 Duchenne patients in the advanced stages of the disease. Although no immunosuppressive treatment was used, none of the patients showed any clinical signs of rejection such as fever, redness, and inflammation. One patient transiently produced antibodies against the donor myoblasts as determined by cytofluorometric analysis. This patient and 2 others were shown to form antibodies against their donor's myotubes. Muscle biopsies of the injected tibialis anterior of 4 patients revealed that 80%, 75%, 25%, and 0% of the muscle fibers, respectively, showed some degree of dystrophin immunostaining. The contralateral noninjected muscles of the latter 3 patients did not contain any dystrophin positive fibers, while that of the first patient showed dystrophin expression in 16% of the fibers examined. Myoblasts were also injected into the extensor carpi radialis longus or the biceps brachii of these patients. A few months subsequent to injection, one patient was shown to have a 143% increase of strength during static wrist extension. This result must be interpreted with caution because a double-blind strength-measuring protocol was not used. Furthermore, we have noted that this change slowly decayed over time. The strength of 2 other patients was increased less remarkably (41% and 51%), while the strength of the fourth patient was unchanged.
Adolescent↗
Administration of pregnenolone and dehydroepiandrosterone to guinea pigs and rats causes the accumulation of fatty acid esters of pregnenolone and dehydroepiandrosterone in plasma lipoproteins.
Steroids were administered continuously to guinea pigs and rats using subcutaneously applied silastic tubing implants, and the effects on circulating steroid and steroid conjugate levels were monitored. Using implants filled with pregnenolone, we observed that pregnenolone had a marked effect on increasing the levels of its fatty acid-esterified derivative, while dehydroepiandrosterone-releasing implants produced a rise in circulating nonconjugated dehydroepiandrosterone, androst-5-ene-3 beta,17 beta-diol, androstenedione, testosterone, and lipoidal derivatives of both dehydroepiandrosterone and androst-5-ene-3 beta,17 beta-diol. Implants filled with androstenedione produced a 20-fold increase in plasma androstenedione levels relative to untreated controls and a corresponding five-fold increase over control testosterone levels. No fatty acid-esterified derivative of testosterone could be detected within the plasma. Lipoproteins were isolated from both rats and guinea pigs treated with implants filled with pregnenolone or dehydroepiandrosterone. The steroid and steroid fatty acid esters present in each fraction were analyzed, revealing that approximately 75% of all the fatty acid esters of pregnenolone recovered in the lipoproteins was localized within the high-density lipoprotein (HDL) fraction of both guinea pig and rat plasma. Similarly, lipoidal dehydroepiandrosterone was found associated predominantly with the low-density lipoprotein and HDL fractions in the guinea pig, while in the rat this steroid conjugate was exclusively within the HDL fraction. High-density lipoprotein-incorporated tritiated pregnenolone fatty acid esters and dehydroepiandrosterone fatty acid esters were injected into castrated male guinea pigs to study the fate of these complexes.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Cellular reaction to the Vascugraft polyesterurethane vascular prosthesis: in vivo studies in rats.
The biocompatibility of Vascugraft, a polyesterurethane vascular prosthesis manufactured by Braun-Melsungen AG, was assessed by immunofluorescence and histological studies. Discs, 1 cm2, of Vascugraft prosthesis were implanted into the peritoneal cavity of rats. Results were compared with Impra, GORE-TEX and Mitrathane prostheses and a control group. Animals were killed at 1, 2, 6, 9 and 12 wk. Total T cells, T helper cells, T suppressor cells and activated T lymphocytes expressing Interleukin-2 receptors were quantified by a cytofluorometric technique in the peripheral blood of rats. For each period of implantation, all vascular prostheses showed no significant change in the percentage of total T cells, T subsets and T cells expressing Interleukin-2 receptors when compared to the control group. Histological examination of the tissue reaction surrounding the Vascugraft revealed a mild inflammatory reaction, similar to the one observed with both polytetrafluoroethylene grafts. However, the rate and the degree of encapsulation were different between grafts. The Vascugraft prosthesis was well encapsulated 2 wk after implantation, whereas inhibition of fibroblastic proliferation into the graft wall and surrounding both polytetrafluoroethylene grafts was observed for each period of implantation. The Mitrathane prosthesis exhibited a moderate inflammatory response, characterized by a high level of activation on fibroblasts compared to other grafts.
Animals↗
Estrogen-stimulated glucuronidation of dihydrotestosterone in MCF-7 human breast cancer cells.
The non-aromatizable androgen dihydrotestosterone (DHT) has been shown to exert a potent inhibitory effect on the proliferation of some human breast cancer cell lines. DHT, however, has little or no significant inhibition on MCF-7 cell proliferation in either the presence or absence of estradiol (E2). Since the metabolism of DHT into non-active compounds may be responsible for the observed lack of androgenic effect in this cell line, we have investigated the metabolic fate of labeled DHT in MCF-7 cells. A time course incubation was performed with 1 nM [3H]DHT and analysis of the various metabolites formed revealed a time-dependent increase in glucuronidated steroids which was stimulated more than 4-fold by 0.1 nM E2. The major glucuronidated steroid was androstane-3 alpha, 17 beta-diol in both control and E2-stimulated cells, comprising 22 +/- 1.2% and 30 +/- 0.6% of the total radioactivity in the medium, respectively. Other steroid glucuronides observed included DHT, androstane-3 beta,17 beta-diol, and androsterone, all of which were elevated in the E2-treated cells relative to control values. The present data show that E2 exerts a stimulatory effect on the glucuronidation of androgens and their metabolites in the estrogen-dependent breast cancer cell line MCF-7. Since glucuronidation is an effective means of cellular elimination of active steroids, such a pathway may be considered as a possible site of regulation of breast cancer cell growth by hormones.
Breast Neoplasms↗
Alteration of voltage-dependent calcium channels in canine brain during global ischemia and reperfusion.
Elevated intracellular calcium (iCa2+) plays an important role in the pathophysiology of ischemic brain damage. The mechanisms by which iCa2+ increases are uncertain. Recent evidence implicates the voltage-dependent calcium channel (VDCC) as a likely site for the alteration in Ca2+ homeostasis during ischemia. The purpose of this study was to determine whether VDCCs are altered by global ischemia and reperfusion in a canine cardiac arrest, resuscitation model. We employed the radioligand, [3H]PN200-110, to quantitate the equilibrium binding characteristics of the VDCCs in the cerebral cortex. Twenty-five adult beagles were separated into four experimental groups: (a) nonischemic controls, (b) those undergoing 10-min ventricular fibrillation and apnea, (c) those undergoing 10-min ventricular fibrillation and apnea followed by spontaneous circulation and controlled respiration for 2 and (d) 24 h. Brain cortex samples were taken prior to killing of the animal, frozen immediately in liquid nitrogen, and crude synaptosomal membranes isolated by differential centrifugation/filtration. After 10 min of ischemia the maximal binding (Bmax) of [3H]PN200-110 increased to greater than 250% of control values (control Bmax 11.16 +/- 0.98; ischemic 28.35 +/- 2.78 fmol/mg protein; p less than 0.05). Bmax returned to near control values after 2 h of reperfusion but remained significantly greater than the control at 24 h. Although the affinity constant (Kd) (control = 0.12 +/- 0.03 nM) appeared to increase with ischemia and normalize with reperfusion, the changes were not statistically significant. We conclude that the binding of [3H]PN200-110 to L-type VDCCs is increased after 10 min of global ischemia/anoxia produced by ventricular fibrillation and apnea in the dog.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Pretransplant and posttransplant antibodies in human corneal transplantation.
The purpose of this study was to measure the association between antibody formation and endothelial corneal allograft reactions in 533 consecutive corneal graft recipients. The median follow-up time of these recipients was 732 days. Pretransplant panel-reactive antibodies were not found to be associated with endothelial corneal allograft reactions. Out of 533 recipients, 239 developed posttransplant antibodies during the course of this study. The formation of posttransplant antibodies was frequent in recipients with pretransplant antibodies and in HLA-A,-B-incompatible recipients. Posttransplant antibodies most often appeared within the first six months after transplantation whereas endothelial allograft reactions most often occurred later. Out of 65 recipients who developed PPRA and underwent an allograft reaction, 53 had a PPRA peak prior to, or at about the time of, the allograft reaction. Corneal allograft reaction events diagnosed during the second and third year after surgery were correlated with PPRA formation during the first year after grafting. The 36-month reaction-free survival rate of transplants was estimated at 72% in recipients with PPRA compared with 86% in recipients without PPRA (log rank P value = 0.002). Furthermore, posttransplant antibody formation altered the outcome of corneal allografts in both HLA-A and -B-compatible and -incompatible recipients. These findings suggest that posttransplant antibody development represents a high risk of endothelial corneal allograft reactions.
Antibodies↗
[An inventory for the evaluation of dangerousness in mental patients].
The authors of the article propose an inventory for the systematic assessment of the dangerousness of psychiatric patients. This clinical tool is qualitative and is helpful in a case-by-case approach. The prediction of violent behaviour is discussed; quantitative and qualitative research perspectives are also mentioned.
Dangerous Behavior↗
Pregnenolone fatty acid esters incorporated into lipoproteins: substrates in adrenal steroidogenesis.
The presence of fatty acid ester derivatives of pregnenolone (PFA) has been recently reported in guinea pig plasma and adrenals. Moreover, it has equally been demonstrated that PFA is present in plasma lipoproteins, including high density lipoproteins (HDL) and low density lipoproteins (LDL). We report here the conversion of LDL- and HDL-incorporated [3H]PFA in guinea pig and bovine adrenocortical cells into nonconjugated steroids, thus indicating that PFA can be used as substrate for steroid production. When guinea pig glomerulosa-fasciculata (FG) cells were incubated for 48 h in the presence of either LDL-incorporated [3H]PFA or HDL-incorporated [3H]PFA, 66 +/- 2% and 47 +/- 1% of the added radioactivity were converted to nonconjugated steroids, respectively. The transformation of LDL-incorporated [3H]PFA into nonconjugated steroids was further increased in FG cells when 10 nmol/liter ACTH were present in the culture medium. This ACTH-induced liberation of nonconjugated steroids from LDL-incorporated [3H]PFA was strongly inhibited by a 10-fold excess of unlabeled LDL, while no competitive effect of unlabeled HDL was observed on the generation of tritiated nonconjugated steroids from HDL-incorporated [3H]PFA. Moreover, nonconjugated metabolites formed during incubation of FG cells with LDL-incorporated [3H]PFA and HDL-incorporated [3H]PFA resembled those observed when FG cells were incubated with tritiated pregnenolone. The formation of nonconjugated steroids was similarly observed when lipoprotein-incorporated [3H]PFA was incubated with bovine adrenocortical cells. Our data suggest that [3H]PFA incorporated into lipoproteins can be internalized into adrenal cells, after which the [3H]PFA is hydrolyzed into nonconjugated pregnenolone, which is readily used as substrate for adrenal steroidogenesis.
Adrenal Cortex↗
Elevated levels of endogenous pregnenolone fatty acid esters in follicular fluid high density lipoproteins support progesterone synthesis in porcine granulosa cells.
Fatty acid esters of pregnenolone (PREG-FA) are present at high levels within ovarian follicular fluid (FF), although no physiological function has yet been attributed to these pregnenolone metabolites. We demonstrate in the following study that PREG-FA are predominantly localized in association with high density lipoproteins (HDL) within FF at levels that surpass those found in plasma HDL by approximately 200-fold. Extensive treatment with dextran-coated charcoal revealed that although nonconjugated steroids could be removed very efficiently from whole fluid and HDL, little effect could be demonstrated on the PREG-FA levels present within the fluid or its HDL component. This observed resistance to charcoal stripping may reflect a steroid-protein interaction that is altogether different from the non-conjugated steroid-protein association. Both plasma and FF-derived HDL were equally effective in supporting PROG biosynthesis in porcine granulosa cell cultures under normal culture conditions, but when PROG synthesis was dramatically blocked by inhibiting the P450 side-chain cleavage enzyme complex with the P450 enzyme inhibitor ketoconazole, only HDL of FF origin was capable of restoring PROG synthesis. Similar cultures that received HDL of plasma origin, containing similar levels of total cholesterol but far less PREG-FA, showed no significant difference in PROG accumulation over control cultures under these conditions. Several reports have described the presence of an entity within FF that was shown to resist charcoal stripping and enhanced PROG synthesis in granulosa cell cultures. Our data suggest that this entity within FF may indeed be the high levels of endogenous PREG-FA. We, therefore, propose a role for PREG-FA as a potential substrate in the biosynthesis of PROG in porcine granulosa cells.
Animals↗
Airway response to inhaled fenoterol in hyperthyroid patients before and after treatment.
Bronchodilatory response to inhaled fenoterol was studied in 15 hyperthyroid patients before and after successful treatment with antithyroid drugs. Baseline forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) were lower than the predicted values in 12 and 11 patients, respectively. Improved values were seen after treatment for hyperthyroidism although statistical significance was not reached. Even if some improvement occurred in PEFR (a rise by 0.24-0.48 L/s) and FVC (increase of 73-78 ml) in the hyperthyroid state in response to fenoterol inhalation after various time intervals, the increase in different parameters of lung function was significantly more after the patients achieved euthyroid state (increases in FVC by 290-165 ml; in FEV1 by 333-193 ml; in peak expiratory flow (PEFR) by 0.75-0.52 L/s and in forced expiratory flow (FEF50%) by 0.55-0.31 L/s). In the euthyroid state the mean absolute improvements from the baseline values were significantly higher (< 0.05-0.001). These observations indicate that bronchodilatory response is impaired in the presence of excess thyroid hormones and improves after euthyroid state is achieved.
Administration, Inhalation↗
Immune reactions after myoblast transplantation in mouse muscles.
Explore the source record for details and available documents.
Animals↗
Human myoblast transplantation between immunohistocompatible donors and recipients produces immune reactions.
Explore the source record for details and available documents.
Animals↗
T lymphocyte modification with the UTA microporous polyurethane vascular prosthesis: in vivo studies in rats.
Sequential quantification of blood T cell subsets by immunocytofluorometry was used to investigate the immune response of microporous polyurethane vascular prostheses after intraperitoneal implantation in rats. The experimental prosthesis, as developed by the University of Texas-Arlington group (UTA), and the Mitrathane prosthesis, as developed by Matrix Med., were implanted for 1, 2 and 6 weeks and compared with ePTFE and wounded rats without prostheses (control group). The implants were examined for histopathology by light microscopy. The percentages of CD4-(helper) and CD8-(suppressor) bearing cells of the PTFE group were significantly lower (p less than 0.05) than the control group 1 week post-implantation. The UTA and the Mitrathane grafts exhibited a significant decrease in both T cell subsets at 1 week, and CD4-bearing cells at 2 weeks. At 6 weeks, T cell subsets were similar among all groups. The ratio of CD4/CD8- cells was similar among all groups except for the PTFE group, which was lower than the control group after 1 week. Histological examination of Mitrathane and UTA grafts showed an acute phase of inflammation which lasted at least 2 weeks. Some foreign body giant cells (FBGC) were present 2 weeks post-implantation, and encapsulation was greater than that observed with PTFE grafts. On the other hand, PTFE grafts exhibited a different pattern of inflammation compared to polyurethane grafts. PTFE implants exhibited a moderate chronic inflammatory response for the first week, as shown by the formation of FBGC. At 2 and 6 weeks, the grafts were encapsulated by a thin layer of collagenous tissue and FBGC were still present around the implants, mostly located in contact with the reinforcing mesh.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Effect of calcium on the dynamic behavior of sialylglycerolipids and phospholipids in mixed model membranes. A 2H and 31P NMR study.
DTSL, a sialic acid bearing glyceroglycolipid, has been deuteriated at the C3 position of the sialic acid headgroup and at the C3 position of the glycerol backbone. The glycolipid was studied as a neat dispersion and in multilamellar dispersions of DMPC (at a concentration of 5-10 mol % relative to phospholipid), using 2H and 31P NMR. The quadrupolar splittings, delta v Q, of the headgroup deuterons were found to differ in the neat and mixed dispersion, suggesting different headgroup orientations in the two systems. In DTSL-DMPC liposomes, two quadrupolar splittings were observed, indicating that the axial and equatorial deuterons make different angles with respect to the axis of motional averaging. The splittings originating from the equatorial and axial deuterons were found to increase and decrease with increasing temperature, respectively, indicating a temperature-dependent change in average headgroup orientation. Longitudinal relaxation times, T1Z, were found to be short (3-6 ms). The field dependence of T1Z suggests that more than one motion governs relaxation. At 30.7 MHz a T1Z minimum was observed at approximately 40 degrees C. At 46.1 MHz the T1Z values were longer and increased with temperature, demonstrating that the dominant rigid-body motions of the headgroup at this field are in the rapid motional regime (greater than 10(8) s-1). DTSL labeled at the glycerol C3 position was studied in DMPC multilamellar dispersions. Whereas two quadrupolar splittings have been observed for other glycolipids labeled at this position, only a single delta nu Q was observed. This shows that the orientation of the C2-C3 segment of DTSL relative to the bilayer normal differs from that of other glycolipids.(ABSTRACT TRUNCATED AT 250 WORDS)
Calcium↗
Lipoprotein-incorporated pregnenolone fatty acid esters act as substrate for ovarian progestin synthesis.
Progesterone is of great importance in the normal development of the ovarian follicle and its biosynthesis has been shown to rely on plasma low-density lipoproteins for delivery of cholesterol substrate. However, the pre-ovulatory ovarian follicle has no access to plasma low-density lipoproteins suggesting that other substrates may be involved in pre-ovulatory progestin production. We show in this study using tritiated pregnenolone fatty acid esters incorporated into lipoproteins can give rise to a series of labelled progestins following lipoprotein-mediated internalization. In doing so, progestins are synthesized by shunting the accepted rate limiting step of steroidogenesis, the intracellular P450 side chain cleavage pathway. Furthermore, we demonstrate that follicular fluid high density lipoproteins contain vast endogenous concentrations of this lipoidal pregnenolone metabolite which may indeed contribute to progesterone production in the pre-ovulatory ovarian follicle.
Animals↗
Purification of a human glucocorticoid receptor gene promoter-binding protein. Production of polyclonal antibodies against the purified factor.
The glucocorticoid receptor (GR) is an essential protein involved in mediating glucocorticoid-regulated gene transcription. The cellular GR concentration is modulated by a number of factors including glucocorticoids, which are capable of down-regulating their own receptor concentration. To further study this phenomenon, the human GR (hGR) gene promoter was isolated and was shown to contain the sequences essential for glucocorticoid-dependent down-regulation in CV-1 cells by gene transfer. Further transfections performed with the hGR gene demonstrated that the nucleotide sequence between -250 and -750 is implicated in the down-regulation of the hGR by hormone. The promoter region of human GR is extremely rich in G+C sequences which are known to be involved in the regulation of many housekeeping genes such as GR, as well as a number of cellular oncogenes. Using a combination of partial purification of DNA-binding proteins, DNA-protein interaction by gel shift analysis and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis, we have identified a protein factor (GRF-1) of 95 kDa which interacts with the human GR gene fragment implicated in homologous down-regulation. Polyclonal antibodies were then raised against the protein following purification. This method of purification and identification may be universally applied to purify and characterize unknown factors which may be involved in the regulation of genes such as hGR gene.
Amino Acid Sequence↗
Multivesicular liposomes containing bleomycin for subcutaneous administration.
Optimal cancer treatment with cell-cycle-specific agents requires maintenance of a cytotoxic drug level for a prolonged period. We explored the use of multivesicular liposomes as a slow-release depot of bleomycin for systemic administration via the s.c. route. The average volume-adjusted liposome size was 19.1 microns, the half-life of leakage in human plasma was 32.1 h, and the half-life of s.c. liposomal bleomycin was 31.8 h. When tested against the s.c. B-16 melanoma model in BDF1 mice, the therapeutic index of single-dose bleomycin given s.c. was significantly improved when the drug was encapsulated in multivesicular liposomes. The efficacy was improved as assessed by both inhibition of tumor growth and increased life span, and the toxicity appeared to be decreased.
Animals↗