Biomedical subjects

N Daniel

Publications and source records attributed to N Daniel.

At least 19 recordsLinked to original sources

PubMed2004

SAPHO syndrome treated with pamidronate: an open-label study of 10 patients.

BACKGROUND: In recent years the SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis and osteitis) has been encountered more frequently. However, clinical evidence indicating superiority of a specific therapeutic modality is still absent. Pamidronate, a second-generation bisphosphonate, has a pronounced effect on bone metabolism by suppressing bone resorption. We report our clinical experience with intravenous pamidronate in SAPHO syndrome. METHODS: Between the years 1999 and 2003 we treated 10 patients with the SAPHO syndrome who did not respond to NSAIDs, oral corticosteroids, colchicine, methotrexate, sulphasalazine or infliximab. All patients were treated with 60 mg pamidronate, given intravenously within an hour. In cases of no response a subsequent dose was given within a month and if there was a partial response an additional infusion was given after 4 months. The primary endpoint was the disappearance of recurrent bouts of bone pain, osteitis or hyperostosis, or recurrent synovitis. Reduction of the frequency of attacks by 50% was regarded as a partial response. RESULTS: Seven of the patients were females and three were males. The age at diagnosis ranged from 26 to 68 yr. All patients had axial or peripheral arthritis and cutaneous involvement; three had severe acne, eight had pustulosis and two had concomitant psoriasis vulgaris. Hyperostosis of the anterior chest wall involving either sternocostal or sternoclavicular joints, as seen on technetium 99 bone scintigraphy, was detected in all patients. Complete remission was observed following therapy in six patients, three others partially responded and only one patient had no response. Two patients needed four cycles of pamidronate infusion, one patient needed three, six needed two infusions and one patient remitted following a single pamidronate infusion. In all but one patient pamidronate was effective in preventing recurrent bouts of pustulosis. CONCLUSION: Pamidronate seems to be a very effective mode of therapy for patients with the SAPHO syndrome, by promoting remission in all components of the disorder, such as bone, joint and skin involvement, and ceases the bouts that characterize this disorder.

Acquired Hyperostosis Syndrome↗

PubMed2001

Tetraspan microdomains distinct from lipid rafts enrich select peptide-MHC class II complexes.

Complexes of peptide and major histocompatibility complex (MHC) class II are expressed on the surface of antigen-presenting cells but their molecular organization is unknown. Here we show that subsets of MHC class II molecules localize to membrane microdomains together with tetraspan proteins, the peptide editor HLA-DM and the costimulator CD86. Tetraspan microdomains differ from other membrane areas such as lipid rafts, as they enrich MHC class II molecules carrying a selected set of peptide antigens. Antigen-presenting cells deficient in tetraspan microdomains have a reduced capacity to activate CD4+ T cells. Thus, the organization of uniformly loaded peptide-MHC class II complexes in tetraspan domains may be a very early event that determines both the composition of the immunological synapse and the quality of the subsequent T helper cell response.

Amino Acid Sequence↗

PubMed2000

Functional heterodimerization of prolactin and growth hormone receptors by ovine placental lactogen.

Although homo- or heterodimerization are common mechanisms for activation of cytokine receptors, cross-talk between two distinct receptors in this superfamily has been never shown. Here we show a physiologically relevant example indicating that such an interaction does occurs, thus raising the hypothesis that heterodimerization between distinct cytokine receptors may be a novel mechanism contributing to the diversity of cytokine signaling. These findings were documented using both surface plasmon resonance and gel filtration experiments and show that ovine placental lactogen (PL) heterodimerizes the extracellular domains (ECDs) of ruminant growth hormone receptor (GHR) and prolactin receptor (PRLR). We also show that PL or PL analogues that exhibit little or no activity in cells transfected with PRLRs and no activity in cells transfected with ovine GHRs exhibit largely enhanced activity in cells cotransfected with both PRLRs and GHRs. Furthermore, chimeric receptors consisting of cytosolic and transmembrane part of ovine GHR or ovine PRLR and ECDs of human granulocyte-macrophage colony-stimulating factor receptor (GM-CSFR) alpha or beta were constructed. Upon transfection into Chinese hamster ovary cells along with reporter luciferase gene and stimulation by GM-CSF, a significant increase in luciferase activity occurred when GM-CSFR-alpha-PRLR and GM-CSFR-beta-GHR or GM-CSFR-alpha-GHR and GM-CSRR-beta-PRLR were cotransfected. In conclusion, we show that ovine PL is capable of functional heterodimerization of GHR and PRLR and that when their cytosolic parts, coupled to the ECD of GM-CSF receptors, are heterodimerized by GM-CSF, they are capable of transducing biological signal.

Animals↗

PubMed2000

The antioxidant ebselen prevents neurotoxicity and clinical symptoms in a primate model of Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), via its major metabolite 1-methyl-4-phenylpyridinium (MPP(+)), produces in primates including humans clinical, biochemical, and neuropathological changes similar to those which occur in idiopathic Parkinson's disease. Ebselen is an antioxidant drug with glutathione peroxidase-like activity and a proven neuroprotective action in stroke patients. Here we show that Ebselen, when administered before, during, and after MPTP injections, prevents both neuronal loss and clinical symptoms in a primate MPTP model of Parkinson's disease. Ebselen also prevents peroxide radical overproduction induced by serum withdrawal in cultured PC12 cells and hydroxyl radical generation induced by the mitochondrial toxin, MPP(+), in vivo in rat brain. Moreover, Ebselen inhibits MPP(+)-induced toxicity in PC12 cells, without interacting with the dopamine uptake system. Our results demonstrate that compounds which prevent mitochondrial dysfunction and free radical production may be useful as preventive treatment of Parkinson's disease.

1-Methyl-4-phenylpyridinium↗

PubMed2000

Antituberculosis activity of once-weekly rifapentine-containing regimens in mice. Long-term effectiveness with 6- and 8-month treatment regimens.

The effectiveness of various once-weekly 10 mg/kg rifapentine (P)- containing regimens for treatment of tuberculosis was assessed in mice infected intravenously with 4.3 x 10(6) colony-forming units (cfu) of Mycobacterium tuberculosis H37Rv, and treated 14 d later with various combinations of rifampin (R), P, isoniazid (H), pyrazinamide (Z), ethambutol (E), or streptomycin (S). Control mice treated daily with either 2-mo HRZ + 4-mo HR or 2-mo HRZ + 6-mo HE were rendered spleen and lung culture-negative at 6 mo and 8 mo, respectively. Treatment failure with emergence of R-resistant bacilli occurred in all mice given once-weekly monotherapy with P for 6 mo. Once-weekly PH treatment was successful at 6 mo when it was preceded by a 2-mo daily phase with HRZ. When the initial daily phase was reduced to 2 wk, once-weekly PH-containing treatment was successful, at 6 mo, only if it was supplemented with S during the initial daily and the once-weekly phases, and at 8 mo if it was supplemented with daily H during the once-weekly phase. Without these supplements, once-weekly treatment failed in some mice with selection of R-resistant or H-resistant mutants.

Animals↗

PubMed1999

[Use of abciximab (Reopro) in the catheterization laboratory and in unstable coronary syndromes].

Blockage of platelet glycoprotein IIb/IIIa receptor by Reopro (c7E3 Fab-abciximab) has been shown to reduce markedly ischemic complications during and following elective and high-risk coronary intervention (CI). Between July '96 and February '98, 120 consecutive patients (85 men and 34 women, aged 34-90--mean 62) received Reopro (20 mg bolus, followed by 10 micrograms/min for 12-48 hours). 100 were treated with Reopro in the catheterization laboratory, in 76 as prophylactic treatment preceding high-risk CI and in 24 as bailout treatment for acute complications during CI. 20 additional patients were treated in the CCU for acute coronary syndromes, 17 of whom underwent CI 6-48 hours later. Coronary angiography demonstrated multivessel disease in 66 (56%), and the target lesions were LAD--77, RCA--41, LCX--22, SVG--6, and 2 unprotected LMCA (total: 148 lesions dilated in 117 patients). Of the 117 CI, 44 were PTCA alone, and 73 included stenting. Indications for prophylactic Reopro for high risk CI were: acute MI (< or = 48 hours), early post-MI angina, unstable AP, and/or complex anatomy with visible thrombus. In this high-risk population the overall success rate (open artery, no MI, discharged alive, no need for urgent re-vascularization) was 97% when Reopro was given prophylactically prior to CI. The success rate was lower (87.5%) when Reopro was given in bailout situations. In 20 patients with acute coronary syndromes treated in the CCU while receiving maximal combined conventional therapy (including full-dose heparin), all symptoms and dynamic ischemic ECG changes disappeared within minutes following Reopro. 17 underwent successful CI during hospitalization and 3 were treated medically. Reopro given prior to high risk CI was associated with a very low rate of complications. In a few cases with acute coronary syndromes, Reopro given in the CCU cases immediate relief of myocardial ischemia and reduced the need for urgent coronary intervention.

Abciximab↗

PubMed1999

Is bowel confinement necessary after anorectal reconstructive surgery? A prospective, randomized, surgeon-blinded trial.

PURPOSE: The aim of this study was to assess any differences between the inclusion or omission of medical bowel confinement relative to postoperative morbidity and patient tolerance after anorectal reconstructive surgery. METHODS: Between January 1995 and February 1997 a prospective randomized trial was conducted for patients without stomas who underwent anorectal reconstructive surgery. All patients were randomly assigned either to medical bowel confinement (a clear liquid diet with loperamide 4 mg by mouth three times per day and codeine phosphate 30 mg by mouth four times per day until the third postoperative day) or to a regular diet, beginning the day of surgery. All patients in both groups underwent the identical preoperative oral mechanical preparation, preoperative oral and parenteral antibiotics, and postoperative antibiotics. Wound closure and wound care were identical in both groups. RESULTS: Fifty-four patients (46 females) were prospectively, randomly assigned to medical bowel confinement (n = 27; 50 percent) or a regular diet (n = 27; 50 percent); the mean ages were 51.0 (range, 28-80) and 47.2 (range, 23-87) years, respectively. Indications for surgery were fecal incontinence in 32 patients, complicated fistulas in 17 patients, anal stenosis in 4 patients, a Whitehead deformity in 1 patient, and a chronic unhealed fissure in 1 patient. Fifty-four patients underwent 55 procedures: 32 patients underwent sphincteroplasty, 18 patients underwent transanal advancement flaps, and 5 patients underwent anoplasties. There were no differences between the two groups in the incidence of either septic or urologic complications. Nausea and vomiting were recorded in seven (26 percent) medical bowel confinement and three (11 percent) regular-diet patients. The first postoperative bowel movement occurred at a mean of 3.9 days in the medical bowel confinement group and 2.8 days in the regular diet group (P < 0.05). Fecal impaction occurred in seven (26 percent) of the patients in the medical bowel confinement group and two (7 percent) of the patients in the regular diet group. Hospital charges analysis showed a mean cost of hospitalization of $12,586.00 (range, $3,436.00-$20,375.00) for the medical bowel confinement group and $10,685.00 (range, $3,954.00-$18,574.00) in the regular diet group, representing a mean difference of $1,901.00 (P = 0.06). Mean follow-up was 13 months for both groups (range, 1-24 months in the regular diet group and 2-25 months in the medical bowel confinement group). No statistical difference was shown in the functional outcome of sphincteroplasties between the medical bowel confinement group and the regular diet group. CONCLUSIONS: The outcome of reconstructive anorectal surgery was not adversely affected by the omission of medical bowel confinement. Moreover, cost savings can be achieved by the omission of routine bowel confinement.

Adult↗

PubMed1999

In vitro expression of long and short ovine prolactin receptors: activation of Jak2/STAT5 pathway is not sufficient to account for prolactin signal transduction to the ovine beta-lactoglobulin gene promoter.

The recent finding that sheep had long (l-oPRLR) and short (s-oPRLR) prolactin receptors provided new tools to further explore prolactin signaling to target genes. Here we used CHO cells transfected with l-oPRLR or s-oPRLR cDNAs to compare the activation of known key steps of prolactin signaling by the two receptors. We found that prolactin stimulated l-oPRLR tyrosine phosphorylation, although it lacked the last tyrosine residue found in other long prolactin receptors. In addition, l-oPRLR and s-oPRLR both responded to prolactin stimulation by (1) Janus kinase 2 (Jak2) tyrosine phosphorylation, (2) DNA-binding activation of signal transducer and activator of transcription 5 (STAT5), (3) stimulation of transcription from a promoter made of six repeats of STAT5-responsive sequence. However, although it contains STAT5-binding consensus sequences, the ovine beta-lactoglobulin promoter (-4000 to +40) was transactivated by l-oPRLR, but not by s-oPRLR. Taken together, our results indicate that activation of Jak2/STAT5 pathway alone is not sufficient to account for prolactin-induced transcription of this milk protein gene, and that sequences of its promoter, other than STAT5-specific sequences, account for the opposite transcriptional activation capabilities of l-oPRLR and s-oPRLR.

Animals↗

PubMed1998

Novel recombinant analogues of bovine placental lactogen. G133K and G133R provide a tool to understand the difference between the action of prolactin and growth hormone receptors.

Two new analogues of bovine placental lactogen (bPL), bPL(G133K) and bPL(G133R), were expressed in Escherichia coli, refolded, and purified to a native form. Binding experiments, which are likely to represent the binding to site 1 only, to intact FDC-P1 cells transfected with rabbit (rb) growth hormone receptor (GHR) or with human (h) GHR, to Nb2 rat lymphoma cells, or to rabbit mammary gland membranes prolactin receptor (PRLR), revealed only small or no reduction in binding capacity. The complex formation between these analogues and receptor extracellular domains (R-ECD) of various hormones was determined by gel filtration. Wild type bPL yielded 1:2 complex with hGHR-ECD, rat PRLR-ECD, and rbPRLR-ECD, whereas both analogues formed only 1:1 complexes with all R-ECDs tested. Real time kinetics experiments demonstrated that the ability of the analogues to form homodimeric complexes was compromised in both PRLR- and GHR-ECDs. The biological activity transduced through lactogenic receptors in in vitro bioassays in rabbit mammary gland acini culture and in Nb2 cells was almost fully retained, whereas the activity transduced through somatogenic receptors in FDC-P1 cells transfected with rbGHRs or with hGHRs was abolished. Both analogues exhibited antagonistic activity in the latter cells. To explain the discrepancy between the effect of the mutation on the signal transduced by PLR versus GHRs we suggest that: 1) the mutation impairs the ability of site 2 of bPL to form a stable homodimeric complex with both lactogenic and somatogenic receptors by a drastic shortening of the half-life of 2:1 complex; 2) the transient existence of the homodimeric complex is still sufficient to initiate the signal transduced through lactogenic receptors but not through somatogenic receptors; and 3) one possible reason for this difference is that JAK2, which serves as a mediator of both receptors, is already associated with lactogenic receptors prior to hormone binding-induced receptor dimerization, whereas in somatogenic receptors the JAK2 receptor association occurs subsequently to receptor dimerization.

Animals↗

PubMed1998

Virion-targeted viral inactivation of human immunodeficiency virus type 1 by using Vpr fusion proteins.

Inactivation of progeny virions with chimeric virion-associated proteins represents a novel therapeutic approach against human immunodeficiency virus (HIV) replication. The HIV type 1 (HIV-1) Vpr gene product, which is packaged into virions, is an attractive candidate for such a strategy. In this study, we developed Vpr-based fusion proteins that could be specifically targeted into mature HIV-1 virions to affect their structural organization and/or functional integrity. Two Vpr fusion proteins were constructed by fusing to the first 88 amino acids of HIV-1 Vpr the chloramphenicol acetyltransferase enzyme (VprCAT) or the last 18 C-terminal amino acids of the HIV-1 Vpu protein (VprIE). These Vpr fusion proteins were initially designed to quantify their efficiency of incorporation into HIV-1 virions when produced in cis from the provirus. Subsequently, CD4+ Jurkat T-cell lines constitutively expressing the VprCAT or the VprIE fusion protein were generated with retroviral vectors. Expression of the VprCAT or the VprIE fusion protein in CD4+ Jurkat T cells did not interfere with cellular viability or growth but conferred substantial resistance to HIV replication. The resistance to HIV replication was more pronounced in Jurkat-VprIE cells than in Jurkat-VprCAT cells. Moreover, the antiviral effect mediated by VprIE was dependent on an intact p6(gag) domain, indicating that the impairment of HIV-1 replication required the specific incorporation of Vpr fusion protein into virions. Gene expression, assembly, or release was not affected upon expression of these Vpr fusion proteins. Indeed, the VprIE and VprCAT fusion proteins were shown to affect the infectivity of progeny virus, since HIV virions containing the VprCAT or the VprIE fusion proteins were, respectively, 2 to 3 times and 10 to 30 times less infectious than the wild-type virus. Overall, this study demonstrated the successful transfer of resistance to HIV replication in tissue cultures by use of Vpr-based antiviral genes.

Gene Products, vpr↗

PubMed1998

Cloning, preparation and characterization of biologically active recombinant caprine placental lactogen.

Caprine placental lactogen (cPL) cDNA was cloned by reverse transcription (RT)-PCR from total RNA of goat placenta. The PCR product encoding for the mature protein was gel purified, ligated to pGEM-T and finally subcloned into a pET8c prokaryotic expression vector. E. coli cells (BL-21) transformed with this vector overexpressed large amounts of cPL upon induction with Isopropyl-1-thio-beta-D-galactopyranoside. The expressed protein, found in the inclusion bodies, was refolded and purified to homogeneity on Q-Sepharose and SP-Sepharose columns, yielding two electrophoretically pure fractions (cPL-Q and cPL-S), composed of over 98% of monomeric protein of the expected molecular mass of approximately 23 kDa. Binding of cPL to the extracellular domain (ECD) of prolactin receptors (PRLR) from rat (r), rabbit (rb), and bovine (b), growth hormone receptors (GHR) from human (h) and rabbit, and binding to rabbit mammary gland membranes revealed similar binding profiles for cPL-Q, cPL-S and ovine (o)PL. Caprine PL was capable of forming 1:2 complexes with hGHR-ECD, rbGHR-ECD, rPRLR-ECD and rbPRLR-ECD whereas with bPRLR-ECD only a 1:1 complex was detected. The biological activity of both cPL fractions resulting from proper renaturation was further evidenced by their ability to stimulate proliferation of Nb2 cells, FDC-P1 cells transfected with rabbit or human GHRs and by stimulation of beta-casein synthesis in rabbit and ovine mammary gland acini cultures.

Amino Acid Sequence↗

PubMed1997

Glutamate-dependent phosphorylation of elongation factor-2 and inhibition of protein synthesis in neurons.

Postischemic delayed neuronal death is attributed to excitotoxic activation of glutamate receptors. It is preceded by a persistent inhibition of protein synthesis, the molecular basis of which is not known. Here we have examined in cortical neurons in culture the regulation by glutamate of phosphorylation of eukaryotic elongation factor-2 (eEF-2) by eEF-2 kinase, a Ca2+/calmodulin-dependent enzyme. Using a phosphorylation state-specific antibody, we show that glutamate, which triggers a large influx of Ca2+, enhances dramatically the phosphorylation of eEF-2. On the basis of kinetic and pharmacological analysis, we demonstrate a close correlation among the increase in cytosolic Ca2+ concentration, the degree of eEF-2 phosphorylation, and the inhibition of protein synthesis. A 30 min treatment with NMDA induced a transient phosphorylation of eEF-2 and delayed neuronal death. However, pharmacological inhibition of protein translation was not neurotoxic by itself and protected neurons against the toxicity evoked by low concentrations of NMDA. Thus, phosphorylation of eEF-2 and the resulting depression of protein translation may have protective effects against excitotoxicity and open new perspectives for understanding long-term effects of glutamate.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed1997

Prolactin signal transduction to milk protein genes: carboxy-terminal part of the prolactin receptor and its tyrosine phosphorylation are not obligatory for JAK2 and STAT5 activation.

In this study, we have developed several Chinese Hamster ovary (CHO) cell clones stably expressing various deletion mutant forms of the rabbit prolactin receptor (rbPRL-R) to better define the domains of the receptor involved in JAK2 kinase interaction, STAT5 activation, and to assess the role of tyrosine phosphorylation of the PRL-R in signal transduction. We observed that the box 1 region of the receptor was critical for productive interaction with JAK2 and its tyrosine phosphorylation after PRL stimulation. However, this region appeared to require the presence of additional cytoplasmic domain region(s), such as box 2, to exert its complete effect. In addition, we found that a mutant form lacking the 141 C-terminal residues lost the capacity to be tyrosine phosphorylated in response to PRL but remained able to activate JAK2 kinase and STAT5 transcription factor, indicating that it contained the minimal sequence required for STAT5 activation. The absence of tyrosine phosphorylation of this C-terminal rbPRL-R mutant upon PRL stimulation indicated that the phosphorylation of the PRL-R normally occured in the last 141 animo acids (aa) containing three tyrosines and was not absolutely necessary for induction of these early events in PRL signal transduction. Transfectant cell lines expressing wild type (WT) PRL-R and this C-terminal mutant form were able to induce CAT activity upon PRL stimulation when transiently transfected with the ovine-beta-lactoglobulin promoter, containing STAT5 recognition sites, fused to the CAT reporter gene. The comparison between transcriptional activity of these two receptor forms leads to the conclusion that the C-terminal region of the rbPRL-R, containing the physiological sites for tyrosine phosphorylation, is probably responsible for an amplification of the PRL signal to milk protein genes.

Animals↗

PubMed1997

Efficiency and productivity of a sheathed fiberoptic sigmoidoscope compared with a conventional sigmoidoscope.

PURPOSE: The aim of this study was to measure and compare time and productivity between a new sheathed flexible sigmoidoscope and a traditional fiberoptic flexible sigmoidoscope relative to labor and cost analysis. METHODS: Two flexible sigmoidoscopes, the Vision Sciences sigmoidoscope using a protective sheath covering requiring removal and replacement between procedures and a conventional flexible sigmoidoscope requiring meticulous cleaning using a washer and high-level disinfection, were compared. Sigmoidoscope preparation was defined as the average time between the procedures (reprocessing, start to finish) and was measured by an independent nonmedical timekeeper JG). The parameter recorded was scope reprocessing time. RESULTS: Ten procedures were performed using the sheathed flexible sigmoidoscope system compared with nine using a conventional sigmoidoscope. Scope performance and endoscopic visualization for both systems were comparable. The average reprocessing time was 46.8 minutes for the conventional sigmoidoscope vs. 4.9 minutes for the sheathed sigmoidoscope (P < 0.0001). The average time saved was 9.5 times greater with the sheathed flexible sigmoidoscope system than with the conventional sigmoidoscope. CONCLUSION: The almost tenfold difference in the time saved using the sheathed flexible sigmoidoscope system represents increased productivity and potentially decreased overall labor cost. By reducing endoscope turnover time, this new sheathed system can reduce or even eliminate the need for backup endoscopes and endoscope washers and potentially allow better use of nursing staff.

Endoscopes↗

PubMed1997

Mechanical bowel preparation for elective colorectal surgery. A prospective, randomized, surgeon-blinded trial comparing sodium phosphate and polyethylene glycol-based oral lavage solutions.

AIM: The aim of this study was to compare the cleansing ability, patient compliance, and safety of two oral solutions for elective colorectal surgery. METHODS: All eligible patients were prospectively randomized to receive either 4 l of standard polyethylene glycol (PEG) solution or 90 ml of sodium phosphate (NaP) as mechanical bowel preparation for colorectal surgery. A detailed questionnaire was used to assess patient compliance. In addition, the surgeons, blinded to the preparation, intraoperatively evaluated its quality. Postoperative septic complications were also assessed. The calcium serum level was monitored before and after bowel preparation. Statistical analysis was performed using the Wilcoxon's rank-sum test and Fisher's exact test. RESULTS: Two hundred patients, well matched for age, gender, and diagnosis, were prospectively randomized to receive either PEG or NaP solutions for elective colorectal surgery. All patients completed all phases of the trial. There was a significant decrease in serum calcium levels after administration of both NaP (mean, 9.3-8.8 mg/dl) and PEG (9.2-8.9 mg/dl), respectively (P < 0.0001), with no clinical sequelae. However, patient tolerance to NaP was superior to PEG: less trouble drinking the preparation (17 vs. 32 percent; P < 0.0002), less abdominal pain (12 vs. 22 percent; P = 0.004), less bloating (7 vs. 28 percent), and less fatigue (8 vs. 17 percent), respectively. Additionally, 65 percent of patients who received the NaP preparation stated they would repeat this preparation again compared with only 25 percent for the PEG group (P < 0.0001). Ninety-five percent of patients who received the NaP solution tolerated 100 percent of the solution compared with only 37 percent of the PEG group (P < 0.0001). For quality of cleansing, surgeons scored NaP as "excellent" or "good" in 87 compared with 76 percent after PEG (P = not significant). Rates of septic and anastomotic complications were 1 percent and 1 percent for NaP and 4 percent and 1 percent for PEG, respectively (P = not significant). CONCLUSION: Both oral solutions proved to be equally effective and safe. However, patient tolerance of the small volume of NaP demonstrated a clear advantage over the traditional PEG solution.

Colonic Diseases↗

PubMed1997

In vivo study of prolactin (PRL) intracellular signalling during lactogenesis in the rat: JAK/STAT pathway is activated by PRL in the mammary gland but not in the liver.

The rat prolactin receptor (PRL-R) exists in two forms, which differ in the length of the cytoplasmic domains, tissue distribution, and biological activity. The short form predominates in liver while the long form is prevalent in mammary gland. We have compared activation by PRL of the JAK2-STAT pathway (protein tyrosine phosphorylation and STAT5 activation) in mammary gland and liver in an in vivo rat model of induction of lactogenesis by PRL injections, and we have studied the relative proportion of both forms of the receptor in these tissues by reverse transcription-polymerase chain reaction. Rats were ovario-hysterectomized on Day 19 of pregnancy, treated with bromocriptine, subsequently injected with 250 micrograms ovine PRL i.p. on Day 20, and killed 0-12 h after. Western blots of solubilized mammary gland and liver membranes immunoprecipitated with anti-PRL-R or anti-JAK2 antibodies showed that the PRL-R is constitutively associated with JAK2 and that the long form of the PRL-R is present in both tissues, while the short form was detected only in liver. Phosphorylated proteins corresponding to the long form of PRL-R and JAK2 appeared 15-60 min after ovine PRL injection in mammary extracts but not in liver. At these same times, an electrophoretic mobility shift assay, using a rat beta-casein probe specific for STAT5 binding, showed activated STAT5 in mammary gland cytosol and nuclear extracts. In the liver, low levels of activated STAT5 were detected in non-treated animals, which were not modified by PRL. Quantitative RT-PCR of liver and mammary PRL-R mRNA showed that the amount of the long form of PRL-R mRNA is roughly comparable in both tissues, while the short form is predominant in liver and in a minority in mammary tissue. Both forms were down-regulated by PRL only in mammary glands. Thus, during lactogenesis, mammary tissue responds to PRL by activation of JAK2 and STAT5, while the liver does not respond to PRL in spite of the presence of PRL-R associated with JAK2 and pre-existing activated STAT5. Thus, liver tissue may lack a critical component for activation of the PRL pathway, or the large quantities of the short form of the PRL-R may associate with the long form to constitute inactive heterodimers.

Animals↗

PubMed1997

Putative alpha-helical structures in the human immunodeficiency virus type 1 Vpu protein and CD4 are involved in binding and degradation of the CD4 molecule.

The human immunodeficiency virus type 1 (HIV-1) vpu gene encodes a 16-kDa class I integral membrane phosphoprotein with an N-terminal membrane-spanning region and a C-terminal cytoplasmic domain. In the cytoplasmic domain, two amphipathic alpha-helices joined by a flexible turn containing two phosphoacceptor sites have been predicted. Previous studies have shown that Vpu downregulates CD4 molecules by inducing their specific degradation in the endoplasmic reticulum. Phosphorylation of serine residues 52 and 56, present within the cytoplasmic domain of the Vpu protein, has been shown to be essential to this Vpu function. However, the contribution of these two phosphoacceptor sites in the mechanism of CD4 degradation remains undefined. Interestingly, a specific interaction between Vpu and CD4 was recently demonstrated in coimmunoprecipitation experiments. Binding of Vpu was shown to be necessary but not sufficient to mediate CD4 degradation, indicating that interaction between Vpu and CD4 represents an early step critical in triggering a process leading to CD4 degradation. To delineate the sequence(s) and/or structural determinant(s) involved in this Vpu-CD4 interaction and in the Vpu-mediated CD4 degradation, we performed a mutational analysis of the cytoplasmic domain of CD4 and Vpu. Coimmunoprecipitation experiments reveal that disruption of the putative alpha-helical structure in the membrane-proximal cytoplasmic domain of CD4 affects the binding to Vpu, suggesting that this structure may act as an interface for the CD4-Vpu interaction that mediates CD4 degradation. Vpu proteins containing mutations in either or both of the phosphoacceptor sites (Ser52 or/and Ser56) were inactive in regard to CD4 degradation yet retained the capacity to interact with the cytoplasmic domain of CD4. In an attempt to define the minimal region responsible for this interaction, we tested a panel of mutations which were designed to affect the integrity of the putative alpha-helices present in the cytoplasmic domain of Vpu. Our results indicate that although both C-terminal alpha-helices are required for degradation of CD4, only alpha-helix I, located in the membrane-proximal cytoplasmic region of Vpu, is involved in the interaction between Vpu and CD4. Taken together, these results demonstrate that alpha-helical structures in the HIV-1 Vpu and CD4 proteins are involved in binding and degradation of CD4 molecules.

Amino Acid Sequence↗

PubMed1997

[Granulomatous interstitial nephritis with acute renal insufficiency, a potential complication of intravesicular bcg therapy].

Intravesical Bacillus Calmette-Guerin has proved to be the most effective treatment of superficial bladder carcinoma. This therapy may induce a renal failure of variable severity, sometimes associated with multiple organ failure. Renal prognosis of this complication is not well defined. We report on a 68 year-old male patient who developed granulomatous hepatitis and acute tubulo-interstitial nephritis with mononuclear infiltrates containing numerous epithelioid cells, following the third course of intravesical BCG. Eleven cases of renal impairment due to intravesical BCG have been previously described, as part of a systemic disease in seven patients. The potential pathophysiological mechanisms of this rare complication are precised.

Acute Kidney Injury↗