Calcium and praseodymium complexes in solution

The synthetic tetrapeptide acetyl-aspartyl-valyl-aspartyl-alanine (Ac-DVDA) is a model of the calcium binding site of proteins such as carp parvalbumin, thermolysin and calmodulin. ¹H n.m.r. spectra of the tetrapeptide are presented and assigned for D₂O and DMSO solutions to determine the conformational mobility. The resonance of the two aspartyl side chains could be completely analysed and the vicinal coupling (C^αH-C^βH and NH-C^αH) indicated that the free peptide has considerable conformational mobility. The Ca(II) complex generates a different ¹H n.m.r. spectrum for the aspartyl resonances at neutral pH. The solution conformation of Pr(III) complex of Ac-DVDA has been investigated using induced chemical shifts. The observed trends in the magnitude of the shift ratios and the rotamer population suggest that the metal ion binds predominantly to both carboxylates of two aspartyl residues in a bidentate fashion. We discuss the consistency of the differentiated spectra for aspartyl residues in the complex with the stepwise binding of Ca²⁺ to the carrier.     

Side reaction during the deprotection of (S-acetamidomethyl)cysteine in a peptide with a high serine and threonine content

The acetamidomethyl (Acm) group is a widely used protecting group for the thiol of cysteine during the SPPS process. We prepared the amino terminal loop of the snake α-neurotoxin, [Cys³, Cys²³, Ser¹⁷(1–24) amide, from the linear peptide [Cys(Acm)^3,23,Ser¹⁷](1–24) amide obtained by SPPS. Three different methods of deprotection of Cys(Acm) and disulfide bond formation were used: iodine, thallium(III) trifluoroacetate and mercuric acetate/potassium ferricyanide. The iodine method failed to yield the expected peptide, and gave instead the mono-iodinated tyrosine analog. The disulfide cyclized peptide obtained by thallium(III) or Hg(II) procedures displayed a MW value observed by mass spectrometry that was higher than the calculated value. The difference (MW_obs - MW_calc) corresponded to a multiple of the Acm moiety, which is shifted intra-and/or intermoleculary. Furthermore, we observed, in addition to the Acm shift in the disulfide cyclized decapeptide with a high Ser and Thr content (model peptide II), the dimerization phenomenon in the Tl(TFA)₃ process. Therefore we conclude that a side reaction, a S–O(Ser,Thr) Acm shift, occured during the Cys(Acm) deprotection. This shift was supported by the demonstration of Ser(O-Acm) formation in the reaction of Boc-(L)-Cys(Acm) with Tl(TFA)₃ in the presence of an equimolar amount of (L)Ser. We report here the efficiency of a trivalent alcohol, glycerol, as scavenger in the both Tl(TFA)₃ and mercuric/ferricyanide methods, in an attempt to circumvent this side-reaction during the disulfide bond formation step starting from a bis-Cys(Acm) peptide with a high Ser and Thr content, such as the N-terminal loop of neurotoxin, model peptide II or a similar peptide.     

STRUCTURAL STUDIES ON YEAST 3-PHOSPHOGLYCERATE KINASE: Linear Arrangement of the CNBr Fragments,Partial Amino Acid Sequence of the Inner Part of the Polypeptide Chain,and Analyses of the N-Terminal Domain of the Protein

The purpose of this work was to contribute to the study of the covalent struc ture of yeast 3-phosphoglycerate kinase. First, we undertook the complete align ment of the four fragments produced by cyanogen-bromide cleavage and which constitute the intact protein; we then established the total amino acid sequence of a 30-residue peptide and the N-terminal sequence of a 65-residue peptide. Second, we analyzed the acetylated state of the protein. The analyses of the acid fraction “P” obtained after digestion of 3-phosphoglycerate kinase by pronase enabled us to determine the N-terminal sequence of this enzyme as N-acetylserylglycine. Third, we isolated, purified and analyzed seven tryptic peptides from a fragment containing 102 amino acids coming from the N-terminal end of the protein. The peptides occupying the N- and C-terminal ends of this fragment were also identified.     

SUPERFICIAL BLADDER TUMORS AND INCREASED REACTIVITY AGAINST MYCOBACTERIAL ANTIGENS BEFORE BACILLUS CALMETTE-GUERIN THERAPY

Purpose

The precise mechanism of action of bacillus Calmette-Guerin (BCG) in bladder cancer treatment remains poorly understood. Whether bladder tumor cells are destroyed by nonspecific mechanisms or targeted by specifically activated lymphocytes recognizing cognate antigens is unclear. To investigate a possible cross-reactivity between BCG and bladder cell tumors, we tested before BCG treatment the lymphoproliferation of peripheral blood lymphocytes against several mycobacterial antigens, including the secreted fibronectin binding antigen 85 complex from BCG (AG 85) in patients with superficial bladder tumors compared to control matched patients.

Materials and Methods

Using a whole blood assay, T cell response against purified protein derivative, BCG extract, whole BCG, purified AG 85, and the nonspecific mitogens pokeweed and phytohemagglutinin was investigated in 79 patients with superficial bladder tumors before BCG and in 39 control subjects without malignancy matched for age and sex. Neither group had a history of tuberculosis. Lymphoproliferation was measured with a tritiated thymidine uptake assay on day 7 of culture.

Results

Of the 79 patients with superficial transitional cell carcinoma, a significant lymphoproliferative response before BCG against PPD, BCG extract, whole BCG and AG 85 was observed in 65 (82.2%), 67 (84.81%), 30 (37.97%) and 49 (62.02%) patients, respectively. Of the 39 controls only 26 (64.1%), 23 (58.9%), 3 (7.7%) and 3 (7.7%) patients, respectively, had a significant lymphoproliferation against PPD, BCG extract, BCG and AG 85 (p >0.05, p = 0.004, p = 0.00001 and p = 0.00001, respectively). In terms of lymphoproliferative levels, patients with superficial transitional cell carcinoma also showed a significantly higher response against PPD (p = 0.000012), BCG extract (p = 0.000001), AG 85 (p = 0.000001), whole BCG (p = 0.00001) and pokeweed (p = 0.01) than controls but not against phytohemagglutinin.

Conclusions

Patients with superficial transitional cell carcinoma demonstrate an increased lymphoproliferation against mycobacterial antigens before BCG compared to control subjects. Although a nonspecific activation of the immune system cannot be excluded at this stage, our data may suggest the possible existence of bladder cancer antigens cross-reactive with mycobacterial antigens responsible for boosting precursor cells witnessing previous contacts with mycobacteria. The implication of these findings in the antitumoral mechanism of action of BCG are under investigation.     

VJ REARRANGEMENTS OF THE TCRγ LOCUS IN PERIPHERAL T-CELL LYMPHOMAS: ANALYSIS BY POLYMERASE CHAIN REACTION AND DENATURING GRADIENT GEL ELECTROPHORESIS

Using Southern blotting for the diagnosis of clonality in peripheral T-cell lymphomas (PTCLs), analysis of the T-cell receptor (TCR) γ gene rearrangement was shown to be more informative than that of the TCR β gene rearrangement. In order to amplify every VJγ rearrangement, a polymerase chain reaction (PCR) procedure using newly designed GC-clamp primers has been developed. All primers can be mixed in a single multiplex PCR. PCR products are analysed by denaturing gradient gel electrophoresis (DGGE), providing tumour-specific imprints inasmuch as the procedure characterizes N sequence polymorphism at the VJ junctions. In a series of 30 PTCL cases, the PCR procedure demonstrated 27 cases to be clonally rearranged and failed in three cases. PCR was more accurate than Southern blotting, showing 47 rearranged γ alleles, four of which were undetectable on the Southern blot. When lymphomas were studied at different sites and at relapse, the DGGE pattern remained unchanged. In PTCL, the proposed PCR is helpful for the diagnosis and staging of the disease and should improve the follow-up monitoring. The undetectability of clonal rearrangements in a few cases is discussed in the light of concepts of lymphomagenesis and T-cell differentiation.     

Sevoflurane for central catheter placement in neonatal intensive care: a randomized trial

Objective: To compare the efficacy and safety of sevoflurane deep sedation with glucose and nonnutritive sucking (GNNS) in reducing the duration of the procedure and in preventing pain‐related effects during peripherally inserted central catheter (PICC) placement. Background: PICC placement in neonatal intensive care is a delicate and stressful procedure that requires pain prevention. GNNS has been recommended in this situation but remain often inefficient. Methods: We designed a randomized controlled study in a sixteen‐bed pediatric and neonatal unit in a tertiary hospital. Fifty‐nine neonates at >28 weeks of gestation with continuous positive airway pressure or invasive mechanical ventilation and requiring PICC placement were included. Patients were randomized to receive inhaled sevoflurane (IS) or glucose and non‐nutritive sucking (GNNS). Procedural duration and conditions, hemodynamic and respiratory parameters, occurrence of movements and complications were compared ( http://clinicaltrials.gov trial register no. NCT00420693). Results: The two groups had similar demographics. There were no between‐group differences in procedural duration (P = 0.84) despite greater immobility in IS group (P = 0.017). IS was also associated with fewer episodes of hypertension (P = 0.003), tachycardia (P < 0.001), and bradycardia (P = 0.02). Occurrences of hypotension were not different between the groups (P = 0.06). The GNNS group showed more desaturation during the 4 h after the procedure (P = 0.03). Complications during intensive care stay did not differ between groups. Conclusion: Inhaled sevoflurane does not make easier catheters placement but prevent pain‐related symptoms. Because sevoflurane is responsible for hypotension, it requires careful monitoring and treatment adaptation.     

COMPLETE PHALLOPLASTY USING THE FREE RADIAL FOREARM FLAP FOR CORRECTING MICROPENIS ASSOCIATED WITH VESICAL EXSTROPHY

PURPOSE: We present a new surgical technique for reconstructing the penis in a man with micropenis associated with vesical exstrophy. MATERIALS AND METHODS: A free radial forearm flap was used to create a penis of normal length and diameter. The flap was wrapped around the native micropenis. A penile prosthesis was then inserted in the flap to provide erection. RESULTS: The flap was well vascularized and no skin damage was observed 6 years after reconstruction. The patient achieved sexual intercourse on a regular basis. He is satisfied with the result. CONCLUSIONS: Free transfer of the radial forearm flap may be done in select men with micropenis associated with vesical exstrophy for penile reconstruction. An inflatable prosthesis may be inserted in the flap to provide erection. The results of this technique have remained stable in the long term. This method provides a new tool for phalloplasty in these difficult cases.     

The Effects of Indomethacin Administration During Pregnancy on Womens' and Newborns' T-Suppressor Lymphocyte Activity and on HLA Class II Expression by Newborns' Leukocytes

ABSTRACT: It has been previously shown that T lymphocytes from human newborns and pregnant women exert a suppressive activity when assayed on the PWM-induced B cell maturation. The mechanisms of the suppression have remained entirely unknown. Prostaglandin E₂, known to trigger T-cell mediated suppressive activity, may be involved. We took advantage of the treatment of pregnant women with indomethacin, because of premature labor or hydramnios, to investigate the role of prostaglandins in the activation of T suppressor (TS) activity. Administration of indomethacin (250 mg/day for 1–7 weeks, then 150 mg/day for 3–12 weeks) during the third trimester of pregnancy, abrogated the TS activity in the nine women and the three newborns tested. Abrogation of TS activity by indomethacin therapy led to normal PWM-induced B cell maturation in pregnant women but not in newborns. Moreover, the low expression of HLA class II antigens observed on normal newborn B lymphocytes and monocytes was corrected in newborns from indomethacin-treated mothers. Our results strongly suggest that prostaglandins may play a role in induction of TS activity observed in normal pregnant women and newborns and in the decreased expression of HLA class II antigens on newborns' leucocytes. Both phenomena could play a role in immunological interactions between mother and fetus.