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C Daniel

Publications and source records attributed to C Daniel.

At least 37 records · Page 2Linked to original sources
PubMed1994

Mapping of linear antigenic sites on the S glycoprotein of a neurotropic murine coronavirus with synthetic peptides: a combination of nine prediction algorithms fails to identify relevant epitopes and peptide immunogenicity is drastically influenced by the nature of the protein carrier.

The elucidation of the antigenic structure of the S glycoprotein of murine coronaviruses will provide further understanding of the complex pathogenicity of these viruses. In order to identify linear antigenic determinants, the primary structure of the S glycoprotein of murine hepatitis virus strain A59 was analyzed with a combination of nine epitope prediction algorithms. Fifteen potential epitopes were synthesized chemically and injected into BALB/c mice to study their biological relevance. This approach failed to identify novel important epitopes. Furthermore, the algorithms were unable to identify as antigenic the previously mapped immunodominant epitope A [C. Daniel, R. Anderson, M. J. Buchmeier, J. O. Fleming, W. J. M. Spaan, H. Wege, and Talbot, P. J. (1993). J. Virol. 67, 1185-1194]. Interestingly, peptide A coupled to KLH induced an immune response that simulated the immune response induced by the corresponding region of the protein much more accurately than when the same peptide was coupled to BSA. This included drastically enhanced competition with monoclonal antibodies and protection from virus challenge. These findings emphasize the shortcomings of amino acid sequence-based epitope prediction algorithms and demonstrate the critical importance of the carrier when synthetic peptides are considered as potential vaccines.

Amino Acid Sequence↗
PubMed1994

Increased viral titers and enhanced reactivity of antibodies to the spike glycoprotein of murine coronavirus produced by infection at pH 6.

Infection of cell monolayers by murine coronavirus A59 at pH 6 rather than 7 yielded a ten-fold increase in the infectious titer and a remarkable enhancement of the reactivities of monoclonal and polyclonal antibodies against the spike glycoprotein in immunoblotting, immunoprecipitation and enzyme-linked immunosorbent assays. These observations are very useful for detecting antibodies against the S glycoprotein of coronaviruses and enhancing infectious titers.

Animals↗
PubMed1994

Monoclonal antibodies to human pancreatic procolipase: production and characterization by competitive binding studies.

Hybridomas secreting monoclonal antibodies (MAbs) specific for human pancreatic colipase were established and 11 clones were selected by using a dot immunobinding assay. Characterization of the MAbs was carried out by using direct and competitive epitope mapping methods, including ELISA and inactivation of colipase-dependent pancreatic lipase. Monoclonal antibodies showed four distinct patterns of reactivity. Monoclonal antibody 5.30 (group I) inhibited colipase-dependent lipase activity. The dissociation constant of the inactive antibody-antigen complex was 10(-9) M. Monoclonal antibodies 48.30, 66.24, and 153.23 (group II) had no effect on activity although they bound competitively with MAb 5.30 to antigen as shown by their capacity to displace MAb 5.30 from the antibody-antigen complex and by ELISA additivity test. Dissociation constants calculated from the displacement curves were 0.9 10(-9) M, 0.6 10(-9) M, and 2 10(-9) M, respectively. Noninhibitory MAbs 13.29, 16.25, and 33.30 bound competitively with MAbs of group II but not with MAb 5.30 (group I). Monoclonal antibodies of group IV (MAbs 17.6, 18.1, 37.39, and 169.29) had no effect on activity and did not react with immobilized antigen. None of the MAbs reacted in ELISA with reduced and carboxymethylated human procolipase, indicating that epitopes involved conformationally dependent determinants on protein antigen. Anti-human colipase MAbs showed no cross-reactivity with porcine or equine procolipases. Monoclonal antibodies described here appear to be useful tools for studying surface hydrophobic domain of colipase and/or interaction between colipase and lipase in its active conformation (open lid).

Animals↗
PubMed1994

Optimizing utilization of DNA from rare or archival anthropological samples.

There is widespread interest in obtaining genetic samples from human populations worldwide for various studies of human genetic diversity. Many samples exist today only in the form of small, rare, irreplaceable, or archival samples, such as material from ancient bone, hair bulbs, or remnants of samples collected in the field decades ago for the purpose of protein and blood type analysis. Here, we describe the application of an approach to amplify DNA, which we call adapter attachment and amplification (AAA). This approach is useful for amplifying the genome in a reasonably representative way from small amounts of starting material using standard PCR-based methods. We apply a version of these methods to DNA extracted from washed red blood cells collected in the 1960s and 1970s in the Amazon basin. AAA and similar approaches may make the analysis of archival samples possible without exhausting that irreplaceable material and may lead to greatly improved efficiency in collecting and using new anthropological genetic samples.

Anthropology↗
PubMed1993

Epitope mapping and immunoinactivation of human gastric lipase using five monoclonal antibodies.

Five monoclonal antibodies (mAb) directed against human gastric lipase (HGL) have been produced by hybridization of myeloma cells with spleen cells of BALB/c immunized mice. All these mAb belong to the IgG1 class with a kappa light chain. The effects of these mAb on the enzymic activity of HGL were studied and used to define three classes of antibodies, depending upon their immunoinactivation properties. As determined by ELISA and immunoinactivation studies, four overlapping epitopes were found to be part of the functional sites of the enzyme. The mAb appear to be suitable probes for studying the lipid binding and catalytic domains of HGL. The results of the ELISA additivity test were used to describe tentatively the epitopes of HGL in terms of a schematic spatial map.

Antibodies, Monoclonal↗
PubMed1993

Identification of an immunodominant linear neutralization domain on the S2 portion of the murine coronavirus spike glycoprotein and evidence that it forms part of complex tridimensional structure.

Numerous studies have demonstrated that the spike glycoprotein of coronaviruses bears major determinants of pathogenesis. To elucidate the antigenic structure of the protein, a panel of monoclonal antibodies was studied by competitive ELISA, and their reactivities were assayed against fragments of the murine coronavirus murine hepatitis virus strain A59 S gene expressed in prokaryotic vectors. An immunodominant linear domain was localized within the predicted stalk, S2, of the peplomer. It is recognized by several neutralizing antibodies. Other domains were also identified near the proteolytic cleavage site, in the predicted globular head, S1, and in another part of the stalk. Furthermore, competition results suggest that the immunodominant functional domain forms part of a complex three-dimensional structure. Surprisingly, some antibodies which have no antiviral biological activities were shown to bind the immunodominant neutralization domain.

Amino Acid Sequence↗
PubMed1993

[Inclusion of microfilaments and conventional cytology. Two complementary techniques applied to products of puncture with fine needle].

A technique has been developed to complete the processing of fine needle aspiration biopsy material of deep and/or superficial organs: a method of collection and "prefixation staining" allowing visualisation of very small coherent fragments (microfragments) obtained by fine needle aspiration biopsy and which can consequently be submitted to histological examination. This method optimises CT-guided fine needle aspiration biopsies which, up until now, were only submitted to cytological examination (smears on slides, cell pellets, concentration and cytocentrifugation). Histological analysis of microfragments of 35 aspiration biopsies of various organs (pancreas, liver, adrenals, retroperitoneal nodes, paravertebral and mediastinal masses, etc.) was contributive in 71.4% of cases (25/35). In conclusion, the combination of cytological and microfragment inclusion techniques increased the diagnostic yield to 80% of cases.

Adenocarcinoma↗
PubMed1992

Is laparoscopic cholecystectomy applicable to patients with acute cholecystitis?

Laparoscopic cholecystectomy will become the standard surgical treatment for gallbladder disease only if the methodology is applicable to all or near all cases. To evaluate this hypothesis, all patients were operated on via the laparoscopic route, regardless of whether or not they had signs of acute infection. Among a total group of 411 patients operated upon laparoscopically, 193 (47%) had clinical or anatomical signs of acute infection. The surgery was somewhat protracted and the hospital stay longer, but no major complication occurred. It can then be concluded that in skilled hands, laparoscopy is a safe route for cholecystectomy in the presence of acute infection and inflammation, and that it offers the benefits of minimally invasive surgery to those patients.

Acute Disease↗
PubMed1990

Protection of mice from lethal coronavirus MHV-A59 infection by monoclonal affinity-purified spike glycoprotein.

Numerous studies have provided indirect evidence that the spike glycoprotein of coronaviruses (E2 or S) bears determinants for pathogenesis and the induction of protective immunity. In order to directly evaluate its immunogenicity, the E2 glycoprotein of the murine hepatitis virus, strain A59, was purified by immunoaffinity chromatography. High titers of neutralizing and fusion inhibiting antibodies were induced in mice vaccinated with purified E2/S in Freund's adjuvant, which were protected from an intracerebral challenge with 10 LD50 of MHV-A59. This study provides a direct demonstration of the importance of the coronavirus spike glycoprotein in the induction of a protective immune response.

Animals↗
PubMed1990

Protection from lethal coronavirus infection by affinity-purified spike glycoprotein of murine hepatitis virus, strain A59.

Murine hepatitis viruses provide excellent animal models for the study of virus-induced diseases of the central nervous system and gastrointestinal tract. Several studies have indirectly provided evidence that the spike glycoprotein (S) of these coronaviruses bears determinants for pathogenesis and the induction of protective immunity. In order to directly evaluate the immunogenicity of this protein, it was purified by affinity chromatography with an in vitro neutralizing and in vivo protective monoclonal antibody which immunoprecipitated the 180-kDa spike glycoprotein of the neurotropic A59 strain of murine hepatitis virus (MHV-A59). Mice immunized twice with approximately 1 micrograms of purified S in Freund's adjuvant developed high titers of neutralizing and fusion inhibiting antibodies, even though the protein was at least partially denaturated after elution from the affinity column. Moreover, these mice were protected from lethal encephalitis when challenged intracerebrally with 10 LD50 of MHV-A59. This study provides a direct demonstration of the importance of the coronavirus spike glycoprotein in the induction of a protective immune response.

Animals↗
PubMed1989

Growth of a murine coronavirus in a microcarrier cell culture system.

The growth of the murine coronavirus MHV-A59 on murine DBT cells adapted to dextran-made Cytodex 1 microcarriers was studied in comparison with cells grown on plastic dishes. With a microcarrier concentration of 5 g/l in spinner flasks, a density of 3 x 10(6) cells/ml was reached in 7 days. Under these conditions, cells supported virus growth to the same extent as when they were grown on the plastic substratum. This was shown by a similar development of virus-induced syncytia, the release of an equivalent number of infectious progeny virions per cell, similar recoveries observed after concentration and purification and an identical appearance of the purified virus under the electron microscope. On the other hand, the technical convenience of microcarriers and the ease of scale-up emphasize their potential for the growth of coronaviruses.

Animals↗
PubMed1987

Physico-chemical properties of murine hepatitis virus, strain A 59. Brief report.

The infectivity of murine hepatitis virus (MHV-A59) was optimally stable at pH 6.0 and was unaffected by ionic strength or at least 15 cycles of freezing and thawing. It was completely inactivated within 25 minutes at 56 degrees C, but was protected by 1 M magnesium chloride or magnesium sulphate. It was completely inactivated within 14 days at 37 and 22 degrees C, but was relatively stable for as long as 72 days at 4 degrees C and optimal pH.

Animals↗
PubMed1987

[Significance of the penile pressure index and value of the papaverine mini-test (8 mg)].

The main non invasive test to quantify arteriogenic impotence is the penile blood pressure (P.B.P.I.). However, its signification is still in discussion. In this work, after discussion of the previous literature, we have revisited the P.B.P.I. signification by quoting it in comparison to the dynamic tests of erection (artificial erection, papaverine test, nocturnal penile tumescence (N.P.T.) with the findings of arteriography. A series of 51 cases having been studied with the multidisciplinary evaluation that we recommend were analyzed and compared to the location of the arterial lesions (aorto-iliac and/or internal pudendal) and to the response to the 80 mg papaverine test (rigidity and initial intracavernous flow (I.I.F.). A significant difference (p less than 0.05) for P.B.P.I. has been demonstrated between normal arteriograms and bilateral lesions. The P.B.P.I. is significantly lower when the lesions are located to the main arteries and bilateral. I.I.F. helps to differentiate hemodynamically severe arterial lesions where surgery is recommended from mild lesions where intracavernous drugs are first proposed. After discussion of the risks of the 80 mg papaverine test in unspecialized units, the authors propose a standardized method to evaluate the penile arteries, using the Doppler and the 8 mg papaverine mini-test which does not carry the risks of prolonged erection. This approach allows a precise morphologic and hemodynamic evaluation for the arterial impotence.

Blood Pressure↗
PubMed1986

Prolactin in partial epilepsy: an indicator of limbic seizures.

A study was performed to evaluate changes in serum prolactin levels after simple and complex partial seizures, and to identify which specific anatomical structures must be involved in seizures for postictal elevation of prolactin levels to occur. Seventy-eight seizures were studied in patients with electrodes implanted bilaterally into amygdala, hippocampus, hippocampal gyrus, and frontal sites. All 38 complex partial seizures had bilateral limbic ictal discharges, and each was followed by a significant increase in prolactin concentration (mean peak, 50.8 ng/ml; range, 16.0 to 150.0 ng/ml). Eight of 10 simple partial seizures with unilateral high-frequency regional limbic discharges were followed by prolactin elevation (mean peak, 28.2 ng/ml; range, 13.4 to 44 ng/ml). Thirty simple partial seizures with other ictal limbic discharges or without limbic discharges were not followed by an elevated prolactin level. The data indicate that serum prolactin levels always rise after complex partial seizures involving the temporal lobes, and rise after certain simple partial seizures involving limbic structures. Thus, measurement of the prolactin level can help identify which simple partial seizures involve mesial temporal lobe structures. Limbic structures serve to trigger prolactin release, which may depend upon spread of the seizure to subcortical structures.

Electroencephalography↗
PubMed1985

Pharmacokinetics and metabolism of the anti-arrhythmic carocainide in man.

The pharmacokinetics and metabolism of the anti-arrhythmic drug carocainide have been investigated in six healthy adult volunteers following single 100 mg intravenous and oral doses. Carocainide was labelled with 14C in the benzofuran ring. After i.v. administration, plasma concentration/time decay of carocainide was triexponential. Mean plasma elimination half-life of the drug was 5.0 +/- 2.2 h (i.v.) and 5.4 +/- 1.1 h (p.o.). Carocainide was virtually completely absorbed after the oral dose. The drug was eliminated mostly as unchanged drug in urine by the two routes of administration. There was some evidence that carocainide underwent enterohepatic cycling. Binding of carocainide to plasma proteins was saturable although not in the concentration range found in vivo. The drug was bound almost entirely to the alpha 1-acid glycoprotein fraction, to one class of binding sites with a moderate affinity constant (5.5 X 10(-4) M-1). Metabolism of carocainide, a secondary elimination process, occurred by oxidative cleavage of the benzofuran ring and by N-oxidation of the pyrrolidine ring.

Administration, Oral↗
PubMed1983

Kinase II-dependent formation of angiotensins II and III in the hepatic circulation.

Experiments were performed in 14 pentobarbital-anesthetized dogs to 1) determine if the hepatic arterial vasoconstrictor effects of [des-Asp1]angiotensin I [( des-Asp1]ANG I) were due to its local conversion to angiotensin III (ANG III) and 2) to evaluate the magnitude of conversion of ANG I to angiotensin II (ANG II) and of [des-Asp1]ANG I to ANG III in the hepatic arterial vascular bed. Graded doses of these peptide agonists were administered as bolus injections directly into the hepatic artery; hepatic arterial blood flow was measured with an electromagnetic flow probe. Dose-response relationships were determined before and during the inhibition of kinase II activity with captopril (2-D-methyl-3-mercaptopropanoyl-L-proline) and antagonism of angiotensin receptor sites with [Ile7]angiotensin III [( Ile7]ANG III). ANG I and [des-Asp1]ANG I were equipotent at all doses tested, as were ANG II and III. At all doses tested, ANG II and III were approximately three times more potent than ANG I and [des-Asp1]-ANG I. Captopril attenuated the vasoconstrictor responses to ANG I and [des-Asp1]ANG I only, whereas [Ile7]ANG III inhibited the responses to all four angiotensin peptides. These data indicate that the hepatic arterial vasoconstrictor responses to [des-Asp1]ANG I were due to the intrahepatic formation of ANG III. The extent of intrahepatic conversion of [des-Asp1]-ANG I to ANG III that occurred in one transit through the hepatic arterial vascular bed was estimated to be 33%, which was similar to the estimated 38% conversion of ANG I to ANG II.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗