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Biomedical subjects

E Paoletti

Publications and source records attributed to E Paoletti.

At least 91 records · Page 5Linked to original sources
PubMed1993

Effects of subcutaneous calcitriol administration on plasma calcium and parathyroid hormone concentrations in continuous ambulatory peritoneal dialysis uremic patients.

OBJECTIVE: To ascertain whether the parathyroid hormone (PTH) secretion of continuous ambulatory peritoneal dialysis (CAPD) uremic patients could be suppressed by repeated subcutaneous injections of calcitriol (CLT). DESIGN: Nonrandomized prospective study with weekly evaluation. SETTING: Hospital CAPD clinic. PATIENTS: Seven uremic CAPD patients with signs of severe hyperparathyroidism. INTERVENTIONS: Patients were treated with CLT (2 micrograms), injected subcutaneously three times a week, on alternate days over a period of 8 weeks. MEASUREMENTS: Plasma PTH, ionized calcium (Ca), serum phosphate (Pi), and alkaline phosphatase (AP) were assayed before the start of CLT therapy and weekly thereafter. RESULTS: The average basal PTH was 349 +/- 26 pg/mL (mean +/- SD). It fell significantly by the fifth week to 158 +/- 20, then leveled off. Analysis of the individual data, however, revealed that only 5 of 7 patients had a significant decrease in plasma PTH. Basal Ca was +/- .02 mmol/L; it increased continuously throughout the study, significantly by the fourth week, reaching a level of 1.33 +/- 0.3 mmol/L at the sixth week, then declined slightly. In those patients with significantly decreased PTH, there was an inverse correlation between PTH and the corresponding Ca levels. CONCLUSIONS: In some CAPD patients subcutaneous administration of CLT significantly suppresses PTH. This effect is mainly mediated via an increase in ionized calcium, but a direct inhibitory effect of the vitamin on parathyroid glands cannot be excluded.

Adult↗
PubMed1992

Immunisation with canarypox virus expressing rabies glycoprotein.

Poxviruses have many useful features as vectors for genes that carry immunising antigens from other viruses, such as ease of production and induction of cellular and humoral immunity, but there is concern about the safety of vaccinia virus. We turned to an avian poxvirus (canarypox); this virus undergoes abortive replication in mammalian cells that enables presentation of early gene products to the immune system. Canarypox virus was used as a vector for the rabies glycoprotein G gene. The safety and efficacy of the recombinant (ALVAC-RG; vCP65) were tested in several animal species, then it was subjected to a phase 1 clinical trial. Twenty-five volunteers were randomly assigned to subcutaneous injections of the recombinant (three groups [A, B, and C] received two doses each of 10(3.5), 10(4.5), and 10(5.5) tissue-culture infectious doses50, respectively) or of human diploid cell culture vaccine (HDC; 6.52 international potency units per dose). 28 days after the second dose, all nine ALVAC-RG group-C subjects and two of three group-B subjects had rabies neutralising antibody concentrations of at least 0.5 IU/ml, the level associated with protection in animals. Although the geometric mean titre of these antibodies at that time was lower in group C than in the ten HDC recipients (4.4 [range 0.9-12.5] vs 11.5 [4.7-25.3] IU/ml), a single booster dose at 6 months induced a recall response in volunteers primed with either vaccine. Side-effects associated with ALVAC-RG were mild and of short duration and occurred at similar frequency to those of HDC vaccine. This study has shown the potential of non-replicating poxviruses as vectors for vaccination in human beings. Trials of canarypox-virus recombinants at higher doses and by other routes of administration are needed.

Adult↗
PubMed1992

Fusogenic segments of bovine leukemia virus and simian immunodeficiency virus are interchangeable and mediate fusion by means of oblique insertion in the lipid bilayer of their target cells.

Modified bovine leukemia virus (BLV) glycoproteins were expressed by using vaccinia virus recombinants, and their fusogenic capacities were examined by a syncytia-formation assay. This analysis indicates that (i) both BLV envelope glycoproteins gp51 and gp30 are necessary for cell fusion; (ii) insertion of the N-terminal segment of gp30 (fusion peptide) into the lipid bilayer in an oblique orientation, as predicted by computer conformational analysis, results in fusogenic capacities higher than insertion in a perpendicular or parallel orientation; and (iii) replacement of the BLV fusion peptide with its simian immunodeficiency virus counterpart does not modify the fusogenic capacity of the BLV glycoprotein.

Amino Acid Sequence↗
PubMed1992

Recombinant vaccinia virus producing the prM and E proteins of yellow fever virus protects mice from lethal yellow fever encephalitis.

Four recombinant vaccinia viruses were constructed for expression of different portions of the 17D yellow fever virus (YFV-17D) open reading frame. A recombinant, vP869, expressing prM and E induced high titers of neutralizing and hemagglutination inhibiting antibodies in mice and was protective against intracranial challenge with the French neurotropic strain of YFV. Levels of protection were equivalent to those achieved by immunization with the YFV-17D vaccine virus. Recombinant vaccinia viruses expressing E and NS1, C prM, E, NS1, or only NS1 failed to protect mice against challenge with YFV despite eliciting antibodies to NS1. The vP869-infected HeLa cells produced a particulate extracellular hemagglutinin (HA) similar to that produced by YFV-infected cells, supporting previous studies with Japanese encephalitis virus (Mason et al., 1991), suggesting that the ability of recombinant vaccinia virus to produce extracellular HA particles is important for effective flavivirus immunity.

Animals↗
PubMed1992

Nonreplicating viral vectors as potential vaccines: recombinant canarypox virus expressing measles virus fusion (F) and hemagglutinin (HA) glycoproteins.

The development of canarypox virus (CPV) recombinants expressing the hemagglutinin (HA) and fusion (F) glycoproteins of measles virus (MV) is described. Inoculation of the CPV-MV recombinants into avian or nonavian tissue culture substrates led to the expression of authentic MVF and MVHA as determined by radioimmunoprecipitation and surface immunofluorescence. In contrast to avian-derived tissue culture, no productive replication of the CPV recombinant was evident in tissue culture cells derived from nonavian origin. On inoculation of dogs, a species restricted for avipoxvirus replication, the recombinants elicited a protective immune response against a lethal canine distemper virus (CDV) challenge. The level of MV neutralizing antibodies and the level of protection induced against CDV challenge achieved by the host-restricted CPV vector were equivalent to that obtained by vaccinia virus vectors expressing the same MV antigens.

Animals↗
PubMed1992

Mice immunized with a subviral particle containing the Japanese encephalitis virus prM/M and E proteins are protected from lethal JEV infection.

Extracellular subviral particles produced by HeLa cells infected with a recombinant vaccinia virus encoding the prM and E genes of Japanese encephalitis virus (JEV) were purified and characterized. These particles contained the JEV prM/M and E proteins embedded in a lipid bilayer, and RNA was not detected in particles using the polymerase chain reaction and primers recognizing a part of the JEV E gene. The particles were uniformly spherical with a 20-nm diameter and had 5-nm projections on their surface. Mice that received a single inoculation of the purified extracellular particles emulsified with Freund's complete adjuvant were fully protected against 4.9 x 10(5) LD50 of JEV. Comparison of the neutralizing and hemagglutination-inhibiting antibody titers and radioimmunoprecipitation data showed that immunization with the particles induced an immune response similar to that following inoculation with the recombinant vaccinia virus.

Animals↗
PubMed1992

A highly attenuated host range-restricted vaccinia virus strain, NYVAC, encoding the prM, E, and NS1 genes of Japanese encephalitis virus prevents JEV viremia in swine.

A highly attenuated strain of vaccinia virus (NYVAC) was engineered to express the Japanese encephalitis virus (JEV) prM, E, and NS1 genes or the prM and E genes. The recombinant viruses were tested as vaccine candidates in pigs, a natural host of JEV. JEV-neutralizing and hemagglutination-inhibiting antibodies appeared in swine sera 7 days after immunization with 10(8) PFU of the recombinant viruses and increased after a second dose at 28 days. The JEV levels detected in the serum after JEV challenge (d56) of the swine with 2 x 10(5) PFU of JEV were significantly reduced in animals inoculated with the recombinant viruses. These results demonstrate the ability of these NYVAC-vectored recombinants to protect pigs from JEV viremia.

Animals↗
PubMed1992

Protection from herpes simplex virus type 2 is associated with T cells involved in delayed type hypersensitivity that recognize glycosylation-related epitopes on glycoprotein D.

Immunization of mice with a vaccinia recombinant (VP176) that expresses a fully glycosylated herpes simplex virus (HSV) glycoprotein D (gD) induces long-term (greater than or equal to 50 days) HSV-specific lymphoproliferation and delayed type hypersensitivity (DTH) responses, the ability to eliminate a high challenge dose of HSV-2 from the epidermis and protection from fatal disease due to HSV replication in the nervous system. Adoptive transfer studies indicate that protection is mediated by the DTH functions of L3T4+ cells and requires the contribution of a non-specific irradiation-sensitive cell. Long-term protection (defined as that seen at greater than or equal to 50 days after immunization) from fatal HSV-2 challenge, virus clearance from the epidermis, and HSV-specific T-cell responses are not induced by a partially glycosylated gD expressed by a vaccinia recombinant (VP254) in which gD is controlled by a late vaccinia virus promoter. However, mice immunized with VP254 are protected from HSV-2 challenge early (day 10) after immunization. The VP254-induced protection is HSV-specific, but it is not mediated by L3T4+ and Lyt2+ cells. The findings are discussed within the context of future developments of anti-HSV vaccines.

Animals↗
PubMed1992

Potential use of non-replicating vectors as recombinant vaccines.

Avipoxviruses, members of the Poxvirus family, are naturally restricted in that productive replication takes place only in avian species. Recent work has described the construction of Avipox recombinants using fowlpox and canarypox viruses. Preparation of recombinant fowlpox viruses which express immunogens from avian pathogens and successful vaccination of poultry have been reported. Recombinant fowlpox and canarypox viruses which express immunogens from mammalian pathogens have also been described and have been demonstrated to provide protective immunity on inoculation in non-avian species. This is a surprising result. Such non-replicating expression vectors provide the possibility of developing safe, effective vaccines which combine the advantages of killed and live vaccines.

Fowlpox virus↗
PubMed1992

Effects of acidity and detergent on in vitro pollen germination and tube growth in forest tree species.

The presence of 1 to 3 mg 1(-1) sodium dodecylbenzensulfonate detergent, or a growth medium pH of 4.0-5.0, inhibited pollen germination and pollen tube elongation more in broad-leaved trees than in conifers. In the broad-leaved species, pollen germination and pollen tube elongation showed similar sensitivities to detergent and acidity, whereas in the conifers, pollen tube elongation was more sensitive than pollen germination to detergent and acidity. Although the germination percentage was low, conifer pollen germinated in the presence of detergent concentrations up to 15 mg l(-1) and at acidities as low as pH 2.5 or 3.0. Pollen germination of most broad-leaved species was completely inhibited in the presence of detergent concentrations of more than 3-5 mg l(-1); the only exceptions were some entomophilous species (e.g., Salix caprea L.) in which the ability of the pollen to germinate in high pollutant concentrations could be related to the presence of tryphyne.

Journal Article↗
PubMed1992

Protection of mice and swine from pseudorabies virus conferred by vaccinia virus-based recombinants.

Glycoproteins gp50, gII, and gIII of pseudorabies virus (PRV) were expressed either individually or in combination by vaccinia virus recombinants. In vitro analysis by immunoprecipitation and immunofluorescence demonstrated the expression of a gII protein of approximately 120 kDa that was proteolytically processed to the gIIb (67- to 74-kDa) and gIIc (58-kDa) mature protein species similar to those observed in PRV-infected cells. Additionally, the proper expression of the 90-kDa gIII and 50-kDa gp50 was observed. All three of these PRV-derived glycoproteins were detectable on the surface of vaccinia virus-PRV recombinant-infected cells. In vivo, mice were protected against a virulent PRV challenge after immunization with the PRV glycoprotein-expressing vaccinia virus recombinants. The coexpression of gII and gIII by a single vaccinia virus recombinant resulted in a significantly reduced vaccination dose required to protect mice against PRV challenge. Inoculation of piglets with the various vaccinia virus-PRV glycoprotein recombinants also resulted in protection against virulent PRV challenge as measured by weight gain. The simultaneous expression of gII and gp50 in swine resulted in a significantly enhanced level of protection as evaluated by weight evolution following challenge with live PRV.

Animals↗
PubMed1991

Reversed-phase high-performance liquid chromatographic analysis of branched-chain keto acid hydrazone derivatives: optimization of techniques and application to branched-chain keto acid balance studies across the forearm.

A sensitive method of quantifying branched-chain keto acids in plasma and whole blood samples is described. It is based on the separation by ion-pair reversed-phase liquid chromatography of 2,4-dinitrophenylhydrazine derivatives with ultraviolet detection. The sample clean-up steps that are usually required for reversed-phase high-performance liquid chromatography are eliminated. A reduction in ketoisocaproate isomer formation is obtained by incubation of derivatives in ice. The method is reproducible (coefficient of variation 2%, n = 5, at the 200-pmol level) and the ultraviolet response is linearly related to branched-chain keto acid concentration. Recoveries are high (greater than 95%). Other keto acids do not co-elute with branched-chain keto acids. Because of its sensitivity and precision, this method can be proposed for whole blood branched-chain keto acid balance studies across organs.

Biological Transport↗
PubMed1991

Japanese encephalitis virus-vaccinia recombinants produce particulate forms of the structural membrane proteins and induce high levels of protection against lethal JEV infection.

Four recombinant vaccinia viruses were engineered for expression of different portions of the Japanese encephalitis virus (JEV) open reading frame. All four recombinant vaccinias contained the NS1 and NS2A genes, and each of these viruses specified the synthesis, glycosylation, and secretion of the nonstructural glycoprotein (NS1). All four recombinants also contained the E gene, and each virus correctly directed the synthesis and glycosylation of the envelope glycoprotein (E). Interestingly, two of these viruses (vP555 and vP650), which expressed the prM gene in addition to E and NS1, produced an extracellular hemagglutinin containing M and E that migrated in sucrose gradients similarly to the slowly-sedimenting hemagglutinin found in the culture fluid of JEV-infected cells. Immunization of 3-week-old mice with the recombinant viruses vP555 and vP658 resulted in immune responses to NS1, whereas only the virus that directed the synthesis of extracellular forms of E (vP555) induced an immune response to E. Both viruses provided protection against lethal challenge with JEV. Animals given two inoculations with vP555 were fully protected from greater than 10,000 LD50 of JEV. This high level of protection was correlated with the production of high titers of neutralizing and hemagglutination-inhibiting antibodies.

Animals↗
PubMed1991

Deletion of 55 open reading frames from the termini of vaccinia virus.

Each copy of the inverted terminal repeat of vaccinia virus consists of 8 kb of DNA containing 9 ORFS flanked near the terminus of the genome by 4 kb of repetitive DNA which in turn contains blocks of tandem repeats. Using plasmids containing repetitive DNA as the external arm, we have generated deletions at both the left and the right termini of the vaccinia genome. We report here the engineered deletion within a single vaccinia virus of 32.7 kb of DNA (including 38 ORFS) from the left terminus and 14.9 kb of DNA (including 17 ORFS) from the right terminus.

Base Sequence↗