Biomedical subjects
Publications and source records attributed to P Rollin.
Tracheal injuries are rare but life threatening complications of anaesthesia. Two therapeutic strategies are presently proposed: a non-surgical strategy for small injuries and a surgical strategy for larger ones. This case report presented the non-surgical therapeutic strategy of a large tracheal injury. This strategy was discussed according to other published reports.
Outbreaks of Ebola virus haemorrhagic fever have been reported from 1994 to 1996 in the province of Ogooué Ivindo, a forest zone situated in the Northeast of Gabon. Each time, the great primates had been identified as the initial source of human infection. End of November 2001 a new alert came from this province, rapidly confirmed as a EVHV outbreak. The response was given by the Ministry of Health with the help of an international team under the aegis of WHO. An active monitoring system was implemented in the three districts hit by the epidemic (Zadié, Ivindo and Mpassa) to organize the detection of cases and their follow-up. A case definition has been set up, the suspected cases were isolated at hospital, at home or in lazarets and serological tests were performed. These tests consisted of the detection of antigen or specific IgG and the RT-PCR. A classification of cases was made according to the results of biological tests, clinical and epidemiological data. The contact subjects were kept watch over for 21 days. 65 cases were recorded among which 53 deaths. The first human case, a hunter died on the 28th of October 2001. The epidemic spreads over through family transmission and nosocomial contamination. Four distinct primary foci have been identified together with an isolated case situated in the South East of Gabon, 580 km away from the epicenter. Deaths happened within a delay of 6 days. The last death has been recorded on the 22nd of March 2002 and the end of the outbreak was declared on the 6th of May 2002. The epidemic spreads over the Gabon just next. Unexplained deaths of animals had been mentionned in the nearby forests as soon as August 2001: great primates and cephalophus. Samples taken from their carcasses confirmed a concomitant animal epidemic.
Epimerisation and subsequent functionalization at C-5 of D-fructopyranose derivatives under Mitsunobu and Garegg's conditions provided efficient access to 5-thio-D-fructose (2) as well as to 5-azido-5-deoxy-1,2-O-isopropylidene-beta-D-fructopyranose (19), a known precursor to 2,5-deoxy-2,5-imino-D-mannitol (3). The interaction of 2 with the D-fructose transporter GLUT5, was found to be weaker than that of D-fructose, a result that suggests involvement of the ring oxygen atom in the recognition of D-fructose by GLUT5.
A liquid chromatographic method has been developed for the analysis of polyglycerol fatty esters and fatty ethers which are non-ionic surfactants. Two methods were compared using either octadecyl silica or porous graphitic carbon. The octadecyl silica system with a hydroorganic mobile phase enables to compare the hydrophobic behavior of the compounds. The porous graphitic carbon enables the separation of the diastereoisomers. Detection of these non-UV-absorbing compounds was achieved by evaporative light scattering detection. Identification of isomers was performed by mass spectrometry.
A novel methodology for the enzymatic preparation from suitably derivatized oligosaccharides of N-linked neoglycopeptides using the microbial glutaminyl-peptide gamma-glutamyl transferase, transglutaminase (TGase), is described. N-Allyl glycosides of various oligosaccharides were photochemically coupled with cysteamine to yield amino-terminated thioether spacers, which were accepted by transglutaminase to transamidate the side-chain gamma-carboxamide group in the dipeptide Z-Gln-Gly.
The isolation of gram-amounts of 2-phenylethyl glucosinolate (gluconasturtiin, GST) from Barbarea verna seeds is reported for the first time. This vegetable source was of crucial importance to isolate GST with a high purity grade and in high yield. Indeed, B. verna seeds contain GST as the only glucosinolate, unlike other sources. The availability at low cost of GST will allow further studies to explain the claimed anticancer activity of its derived phenylethyl isothiocyanate.
(5R)-5-Vinyl-1,3-oxazolidine-2-thione, (2S)-1-cyano-2-hydroxy-3-butene, and two diastereoisomeric erythro-(2S)- and threo-(2S)-1-cyano-2-hydroxy-3,4-epithiobutanes were prepared in pure form starting from (2S)-2-hydroxybut-3-enyl glucosinolate (epiprogoitrin). This glucosinolate was isolated in almost pure form using ripe seeds of Crambe abyssinica and then hydrolyzed under different conditions. The hydrolysis was carried out using either myrosinase immobilized on nylon, to produce (5R)-5-vinyl-1,3-oxazolidine-2-thione, or the endogenous myrosinase contained in defatted crambe meals, to produce the other epiprogoitrin-derived products. After purification and physicochemical characterization, all four myrosinase degradation products were tested for their biological activity. A bioassay on Lactuca sativa was chosen as a simple test to determine their apparent action on living tissues. (5R)-5-Vinyl-1,3-oxazolidine-2-thione negatively affected mainly root growth, whereas (2S)-1-cyano-2-hydroxy-3-butene affected the early phase of germination, and both (2S)-1-cyano-2-hydroxy-3,4-epithiobutane diastereoisomers appeared to negatively affect both germination and root growth at doses 5-10 times lower than those of (2S)-1-cyano-2-hydroxy-3-butene or (5R)-5-vinyl-1,3-oxazolidine-2-thione.
Myrosinase, an S-glycosidase, hydrolyzes plant anionic 1-thio-beta-d-glucosides (glucosinolates) considered part of the plant defense system. Although O-glycosidases are ubiquitous, myrosinase is the only known S-glycosidase. Its active site is very similar to that of retaining O-glycosidases, but one of the catalytic residues in O-glycosidases, a carboxylate residue functioning as the general base, is replaced by a glutamine residue. Myrosinase is strongly activated by ascorbic acid. Several binary and ternary complexes of myrosinase with different transition state analogues and ascorbic acid have been analyzed at high resolution by x-ray crystallography along with a 2-deoxy-2-fluoro-glucosyl enzyme intermediate. One of the inhibitors, d-gluconhydroximo-1,5-lactam, binds simultaneously with a sulfate ion to form a mimic of the enzyme-substrate complex. Ascorbate binds to a site distinct from the glucose binding site but overlapping with the aglycon binding site, suggesting that activation occurs at the second step of catalysis, i.e. hydrolysis of the glycosyl enzyme. A water molecule is placed perfectly for activation by ascorbate and for nucleophilic attack on the covalently trapped 2-fluoro-glucosyl-moiety. Activation of the hydrolysis of the glucosyl enzyme intermediate is further evidenced by the observation that ascorbate enhances the rate of reactivation of the 2-fluoro-glycosyl enzyme, leading to the conclusion that ascorbic acid substitutes for the catalytic base in myrosinase.
A transglutaminase-catalyzed transacylation is the major step in a practical, regioselective synthesis of N-linked spacer-modified glycopeptide analogues. The process requires minimal modification of the saccharide during the N-glycosylation, photoinduced coupling of cysteamine, and final enzymatic reaction (see scheme).
A new semi-synthetic way to produce glucoraphanin (2), the bio-precursor of the potential anticarcinogen sulforaphane (3), has been developed. Starting from glucoerucin (1), isolated from ripe seeds of Eruca sativa, glucoraphanin was obtained through chemoselective oxidation. Controlled myrosinase-catalysed hydrolysis of this precursor quantitatively afforded sulforaphane.
Glucosinolates hydrolysis products are attracting increasing attention since many studies have suggested that they may be involved in the anticarcinogenic property of cruciferous vegetables. In this study, we show that diindolylmethane (DIM) and sulforaphane, produced during the hydrolysis of glucobrassicin and glucoraphanin, respectively, exert a dose-dependent cytotoxicity on human colon adenocarcinoma HT29 cells. Moreover, these products are able to inhibit quiescent cells to re-enter the cell cycle. Interestingly, our results clearly show that low doses of DIM and sulforaphane, although very effective on undifferentiated intestinal HT29 cells, do not affect the viability of the differentiated CaCo2 cells. The reversibility of their effects has also been tested and is discussed.
OBJECTIVE: To describe the clinical characteristics of intrauterine infection with lymphocytic choriomeningitis (LCM) virus, an uncommonly recognized cause of congenital viral infection. PATIENTS: Three infants born in the midwestern United States in 1994 and 1995 with clinical features and serologic studies consistent with congenital LCM virus infection and cases of congenital infection identified by review of the medical literature between 1955 and 1996. RESULTS: Twenty-six infants with serologically confirmed congenital LCM virus infection were identified. Twenty-two infants were products of term gestations, and birth weights ranged from 2384 to 4400 g (median, 3520 g). Ocular abnormalities, macrocephaly, or microcephaly were the most commonly identified neonatal features. Twenty-one infants (88%) had chorioretinopathy, 10 (43%) had macrocephaly (head circumference >90th percentile) at birth, and 3 (13%) were microcephalic (head circumference <10th percentile). Macrocephaly and hydrocephalus developed postnatally in one of the latter infants. Hydrocephalus or intracranial calcifications were documented in five infants by computed tomography or magnetic resonance imaging. Nine infants (35%) died, and 10 (63%) of the 16 reported survivors had severe neurologic sequelae, consisting of spastic quadriparesis, seizures, visual loss, or mental retardation. One-half of the mothers reported illnesses compatible with LCM virus infection, and 25% reported exposures to rodents during their pregnancies. CONCLUSIONS: These cases suggest that congenital LCM virus infection could be an underrecognized cause of congenital infection among infants born in the United States. Because of the clinical similarities of these congenital infections, cases of congenital LCM virus infection can be confused with infections with cytomegalovirus or Toxoplasma gondii.
Using synthetic deoxy-glucotropaeolins (6d-GTL, 4d- GTL, 3d-GTL, 2d-GTL) as substrates, myrosinase activity was studied in comparison to that determined on native glucotropaeolin (GTL) isolated from ripe Lepidium sativum seeds. When the deoxy substrates were used, in addition to an overall strong reaction rate decline, a significant decrease in the reaction rate was observed in going from 6d- to 2d-GTL. This finding allows us to propose a mechanism of catalysis which appears to be similar in many respects to that established for beta-glucosidases. Finally, 2d-GTL was shown to be the first strong competitive inhibitor of myrosinase ever reported.
Plaque-reduction neutralization tests were done with eight of nine known representative hantaviruses and immune sera from experimentally infected animals and from patients with hemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary syndrome (HPS). Results obtained with animal sera demonstrated each virus to be antigenically unique. Neutralization with the HPS patient sera was highest with Sin Nombre (SN) virus and to a lesser extent with Black Creek Canal (BCC) virus. Sera from Korean HFRS patients reacted best with Hantaan virus, but cross-reactivity with all other viruses except Thottapalayam (TPM) virus was also observed. Sera from Swedish HFRS patients reacted best with Puumala virus but cross-reacted with Prospect Hill, SN, and BCC viruses and to a lesser extent with all of the other viruses except TPM virus.
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The suckling mouse brain rabies vaccine, recommended for production and routine use in Nigeria from our previous study, was investigated in the present study in an effort to reduce the cost of antirabies treatment in the country. This is needed for economic reasons. Instead of seven daily doses followed by three boosters, we tried five daily doses followed by three boosters, with or without equine hyperimmune serum given on day 0 (40 IU per kg body weight). Fifty dog-bite, victims, aged 3-81 years, were placed on this regimen, 25 with serum and 25 without serum, according to the history of the case. The serum had no effect on the kinetics of antibody development and both serum and vaccine were well tolerated. The geometric mean titres (GMTs) of antirabies antibodies in the sera of recipients of vaccine alone on days 10, 28 and 90 were 3.05 equivalent units ml-1 (EU ml-1), 4.35 EU ml-1 and 2.54 EU ml-1 respectively. Among those who had received antiserum and vaccine the titres were respectively 3.19 EU ml-1, 4.35 EU ml-1 and 3.02 EU ml-1. Of the 50 subjects, 49 showed detectable antibodies by day 28, and all the 50 survived. This regimen is therefore recommended for further trial in countries where rabies is endemic but potent antirabies vaccines are scarce and expensive. Another 23 subjects, considered not to be at risk of rabies, were given a one-tenth dose, two-site intradermal inoculation of the same vaccine on days 0, 3, 7, 14, 28 and 90.(ABSTRACT TRUNCATED AT 250 WORDS)