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Biomedical subjects

C Prieto

Publications and source records attributed to C Prieto.

At least 55 records · Page 3Linked to original sources
PubMed1996

Exposure of gilts in early gestation to porcine reproductive and respiratory syndrome virus.

Twenty-five gilts without measurable serum antibody titres to porcine reproductive and respiratory syndrome virus (PRRSV) were identified and 16 were inoculated with PRRSV at seven, 14 or 21 days of gestation and killed 20 to 22 days later to determine the effect of the virus on their embryos. The remaining nine gilts were not exposed to PRRSV, but were killed at the same stages of gestation. The gilts were observed for clinical signs of infection and the gilts and their embryos were tested for PRRSV and homologous antibodies. The infection was demonstrated by the re-isolation of the virus and its detection by the reverse transcriptase polymerase chain reaction in serum and other tissue samples from the inoculated gilts, and also by seroconversion. However, the gilts remained healthy throughout the study, except for one which was depressed and anorexic for two days. Two of the litters from the gilts challenged with PRRSV on day 14 of gestation contained one and three infected live embryos; the other embryos from these two litters did not contain detectable virus, although most of the embryos in one of the litters were dead. The other nine litters from the gilts challenged with PRRSV and the control litters, showed no evidence of infection.

Animals↗
PubMed1996

Semen changes in boars after experimental infection with porcine reproductive and respiratory syndrome (PRRS) virus.

Eleven boars seronegative to porcine reproductive and respiratory syndrome virus (PRRSV) were trained for semen collection: five boars were inoculated intranasally with 6 x 10(6)TCID(50)/ml of PRRSV (Group A); four boars were inoculated intranasally with 6 x 10(4)TCID(50)/ml (Group B); and two boars were used as uninfected control (Group C). Semen samples were collected at 7-d intervals from 49 d prior to experimental inoculation with PRRSV to 70 d after inoculation, and were examined for sperm volume, sperm concentration, sperm morphology, sperm motility and for the presence of PRRSV. The infection in boars was demonstrated by the reisolation of PRRSV from the serum of all inoculated boars. Rectal temperatures and general health of the boars were clinically normal throughout the trial. Differences were observed in the quality of semen collected from boars after experimental infection with PRRSV. This infection induced a significant decrease in sperm motility and in spermatozoa with normal acrosomes. Of the semen samples tested for virus isolation in swine alveolar macrophages PRRSV was only isolated in 1 boar from Group B. The virus was detected in an additional semen sample in Group A by the production of an antibody titer in a biological assay. All attempts to detect PRRSV by RT-PCR in semen samples were unsuccessful. Nevertheless, from our study it is possible to suggest that the PRRSV can occasionally be transmitted in the semen during the initial phase of the disease.

Journal Article↗
PubMed1996

Effect of porcine reproductive and respiratory syndrome virus (PRRSV) on development of porcine fertilized ova in vitro.

Fertilized pig ova, collected from 14 estrus-synchronized gilts 32 h after presumed ovulation were microinjected or cultured for 72 h in Beltsville Embryo Culture Medium-3 with or without Porcine Reproductive and Respiratory Syndrome Virus (PRRSV). To detect virus in the samples, virus isolation of swine alveolar macrophage, Reverse Transcriptase Polymerase Chain Reaction and Fluorescent Antibody techniques were employed. Microinjection or incubation of embryos with PRRSV did not significantly inhibit development of the porcine embryos in vitro when compared with that of controls (P = 0.75 and P = 0.14, respectively). Although either 10 to 20 TCID50 were microinjected or large concentrations of virus were used for embryo exposure by incubation, PRRSV was not detected in association with the embryos. It is concluded based on the experiments reported here that 4- to 16-cell stage pig embryos are not susceptible to productive infection with PRRSV in vitro.

Journal Article↗
PubMed1996

Phylogenetic relationships of european strains of porcine reproductive and respiratory syndrome virus (PRRSV) inferred from DNA sequences of putative ORF-5 and ORF-7 genes.

The complete ORF-5 gene and a fragment of the ORF-7 gene from 14 different European porcine reproductive and respiratory syndrome virus (PRRSV) isolates were amplified by reverse transcriptase polymerase chain reaction (RT-PCR), and their nucleotide sequences were determined. The ORF-7 gene displayed nucleotide and amino acid identities of 94.1-99.6% and 95.3-100% among isolates from different countries. The ORF-5 gene showed higher nucleotide (87.1-99.2% identity) and amino acid (-88% identity) variability. The resulting sequences were aligned with other European and North American PRRSV strains and phylogenetic relationships among these strains were established by the maximum parsimony method. The phylogenetic trees inferred from both genes were in agreement and showed that European and North American PRRSV strains clearly represent two different genotypes. According to both trees, there is a perfect correlation between strains and the countries in which they were isolated. Additionally, the phylogenetic position of European and North American PRRSV strains within the recently proposed family Arteriviridae was also analyzed.

Animals↗
PubMed1996

Open reading frame 5 of porcine reproductive and respiratory syndrome virus as a cause of virus-induced apoptosis.

The gene product of open reading frame 5 (p25) of porcine reproductive and respiratory syndrome (PRRS) virus has been expressed by coinfection of culture cells with vaccinia virus expressing the T7 RNA polymerase and a recombinant vaccinia virus encoding the open reading frame 5 gene under the T7 promoter and the encephalomyocarditis virus internal ribosome entry site. In spite of the reported efficiency of the expression system, very poor accumulation of p25 protein was observed and a strong cytotoxicity was produced in the doubly infected cells. This cell toxicity was shown to occur by induction of apoptosis, as indicated by nucleosome ladder formation, chromatin condensation, and rRNA degradation. Apoptosis induction was also observed after infection of cultured cells with an adapted PRRS virus strain and after infection of swine macrophage cells with a PRRS virus field strain. Contrary to the observations made for other cases of virus-induced apoptosis, we could not prevent p25 protein-induced apoptosis by using a cell line permanently expressing Bcl-2 protein.

Animals↗
PubMed1996

US and color Doppler imaging of ocular and orbital disease in the pediatric age group.

Ultrasonography (US) is a rapid, accurate, noninvasive method of evaluating ocular and orbital disease. A wide spectrum of pediatric ocular and orbital disorders can be demonstrated with US: ocular congenital malformations, vitreoretinal disorders, primary and metastatic ocular and orbital neoplasms, inflammatory and congestive disease (focal or systemic), cystic disease, trauma, and foreign bodies. US may be the method of choice for studying ocular congenital anomalies and vitreoretinal disorders owing to its high definition and noninvasiveness. In ocular neoplasms, US demonstrates the morphology of the lesion, its solid or liquid nature, and the presence of calcifications. Its use is limited when the tumor extends outside the globe; computed tomography (CT) or magnetic resonance (MR) imaging must then be performed. In ocular trauma, US precisely demonstrates the presence of hemorrhage, retinal and choroidal detachment, and foreign bodies. CT and MR imaging are superior in evaluation of orbital disease. Color Doppler US often allows differential diagnosis of vascular, inflammatory, and neoplastic disease.

Child↗
PubMed1995

Shwachman-Diamond syndrome: clinical, radiological and sonographic aspects.

Six children with Shwachman-Diamond syndrome have been diagnosed and treated in our hospital since 1986. We describe the radiological and sonographic findings of this rare disease which is characterized by metaphyseal chondrodysplasia, neutropenia and pancreatic exocrine insufficiency. It presents with variable extremity shortening, "cup" deformation of the ribs, metaphyseal widening and hypoplasia of the iliac bones, and increased echogenicity of the pancreas without change in size. We discuss the differential diagnosis and review the literature.

Bone Marrow↗
PubMed1995

Shwachman-Diamond syndrome: clinical, radiological and sonographic findings.

Six children with Shwachman-Diamond syndrome have been diagnosed and treated in our hospital since 1986. We describe the radiological and sonographic findings of this rare disease, which is characterized by metaphyseal chondrodysplasia, neutropenia and exocrine pancreatic insufficiency. It presents with varying extremity shortening, "cup" deformation of the ribs, metaphyseal widening and hypoplasia of the iliac bones, as well as increased echogenicity of the normalized pancreas. We discuss the differential diagnosis and review the literature.

Bone Marrow Diseases↗
PubMed1995

Residual cavities after surgery for hepatic hydatid cysts--an ultrasonographic evaluation.

Ultrasonography has made it easier to diagnose precisely hepatic hydatid cysts, but the interpretation of images of residual cavities persisting long after the operation can be difficult. We reviewed the clinical histories of 22 children treated surgically for hepatic hydatid cysts at our hospital (1985-1992) to find clues to the proper attitude toward residual cavities. The children's mean age was 7.4 +/- 2.5 years. Fourteen children had single cysts (11 right and 3 left) and 8 children had multiple cysts, one of them 30 cysts (16 right and 14 left). The mean ultrasonographic diameter of the 44 cysts was 6.1 +/- 3 cm. Cystectomy with partial pericystectomy was performed in every case. Six months after operation, 29 cavities had disappeared, became calcified, or were substituted with fibrous scar tissue. The remaining 15 residual cavities had a mean diameter of 3 +/- 1 cm. The residual cavities exhibited little change at 12 months (2.8 +/- 1 cm), but at 18 months 9 had disappeared, 2 that increased in size and 4 remained the same size. Of these 4 stable lesions, surgery performed in 2 found no cysts and 2 have been followed-up ultrasonographically for 5 years. This short series shows that ultrasonography is useful in the diagnosis and follow-up of residual cavities after surgery for hepatic hydatid cysts. Most residual cavities disappeared by 18 months. In the cavities that persisted, our findings suggest that surgical treatment is justified only when the cyst becomes larger on ultrasonography.

Child↗
PubMed1995

Effect of dietary protein quality on energy metabolism in growing chickens.

A slaughter experiment was carried out to study the effect of dietary protein quality on maintenance energy requirements and energy costs for protein accretion and fat deposition in fast-growing broiler-type male chickens. Three isonitrogenous (200 g crude protein/kg DM) and isoenergetic (14 kJ metabolizable energy (ME)/g DM) semipurified diets based on soyabean meal unsupplemented (diet S) or supplemented with 20 g L-lysine/kg (diet SL) or 2 g DL-methionine/kg (diet SM), in order to promote a decrease or an increase in growth rate respectively, were selected and given at four feeding levels (ad lib. or restricted to 40, 28 and 18 g DM/d, on average) to 10-d-old fast-growing male broiler-type chicks for 2 weeks. Both the efficiency with which ME was used to support growth (kg) and the maintenance requirements (MEm) significantly decreased inversely to the biological value of the dietary protein (kg = 0.660, 0.600 and 0.572; MEm = 597, 522 and 464 kJ/kg W0.75 per d, for diets SL, S and SM respectively). The partial efficiencies of use of ME for protein accretion (kp) or fat deposition (kf) were also inversely related, the former increasing with the quality of the protein offered. An alternative procedure was used to try to overcome the statistical problems inherent in the partition of ME between fat and protein.

Animal Feed↗
PubMed1995

A confinement respiration chamber for short gaseous exchange measurements.

The present work deals with the construction and function of a confinement chamber for small ruminants intended for use in short energy metabolism studies. CH4, CO2 and O2 are analysed according to physical principles. Several calibration tests of the whole system were carried out with satisfactory results. A close agreement has been observed when comparing the values of day-to-day variation heat production obtained by confinement and open-circuit calorimetry.

Animals↗
PubMed1995

Sonography of pancreatic disease in infants and children.

The usefulness of sonography in evaluating the pancreas in infants and children is well known. Its usefulness is due to the optimal sonic window provided by the relative lack of fat tissue and the large left hepatic lobe in children. A wide spectrum of pancreatic pathologic conditions can be identified sonographically in children, including congenital abnormalities; inflammatory, cystic, pseudocystic, and neoplastic lesions in usual and unusual manifestations; rare processes such as nesidioblastosis and Schwachman-Diamond syndrome; and pancreatic involvement in systemic disease. Multiple pathologic processes can affect the pancreas focally or diffusely, making diagnosis difficult in some instances, since the pancreatic response is limited to changes in echogenicity and size independent of the cause. Sonography is rapid, accurate, and noninvasive and does not require patient sedation. It is the modality of choice for evaluating suspected pancreatic disease, since it allows not only direct visualization of the pancreas but also evaluation of adjacent organs.

Adolescent↗
PubMed1994

Direct detection of the porcine reproductive and respiratory syndrome (PRRS) virus by reverse polymerase chain reaction (RT-PCR).

A method for direct detection of the porcine reproductive and respiratory syndrome (PRRS) virus was developed, based on reverse transcription of the viral RNA coupled to DNA amplification by polymerase chain reaction. A set of primers was designed from Lelystad virus sequence within ORF 7 encoding nucleocapsid protein. From seven Spanish field isolated strains the 312 bp amplified fragment was cloned and sequenced. Alignment with Lelystad virus sequence revealed a 96-97% homology. A maximum sensitivity of 6.7 TCID50 was achieved with the reported procedure in experimentally infected swine alveolar macrophages cultures. The sensitivity obtained in crude clinical samples from experimentally infected 3-weeks old pigs was approximately 10(2) TCID50. High specificity for the PRRS virus was demonstrated for the method, as none of the seven common swine virus assayed rendered DNA amplification product.

Animals↗
PubMed1994

Effect of dietary protein quality, feed restriction and short-term fasting on protein synthesis and turnover in tissues of the growing chicken.

The effect of dietary protein quality and quantity on fractional rates of protein synthesis (ks) and degradation (kd) in the skeletal muscle, liver, jejunum and skin of young growing chickens was studied. Chickens were either fasted overnight or were fed at frequent intervals, using continuous feeders, with equal amounts of a diet containing soya-bean meal as the sole protein source, unsupplemented, or supplemented with either lysine or methionine. Each of the three diets was provided at 2 or 0.9 x maintenance. On the higher intake, birds on the unsupplemented diet gained weight, lysine supplementation decreased and methionine supplementation increased body-weight gain (by -23% and +22% respectively). Birds fed at 0.9 x maintenance lost weight; supplementation with methionine or lysine did not influence this weight loss. None of the dietary regimens had significant effects on protein synthesis rates in any of the tissues, thus the mechanism whereby muscle mass increased in response to methionine supplementation appeared to be a decrease in the calculated rate of protein degradation. Similarly, on the 0.9 x maintenance diet the failure of the animals to grow appeared to be due to an increase in the rate of protein degradation rather than an effect on synthesis. Conversely, muscle ks was decreased in fasted chickens previously fed on the unsupplemented diet at 2 x maintenance, and in birds which had received the 0.9 x maintenance diet fasting resulted in a similar reduction in protein synthesis in muscle; ks in the liver and jejunum was also significantly decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1994

Biochemical traits and antimicrobial susceptibility of Streptococcus suis isolated from slaughtered pigs.

A total of 522 Streptococcus suis isolates were recovered from the tonsils of slaughtered pigs by culturing on media containing different specific antisera. The serogroup reactions were determined by coagglutination. The most frequently isolated serotype was serotype 4 (representing 28.7% of the isolates), followed by serotype 3 (24.9%) and serotype 2 (22.6%). Typable isolates were examined by growth in 6.5% NaCl, amylase activity, acetoin production, susceptibility to optochin and production of acid from mannitol, melibiose, raffinose, salicin, sorbitol and trehalose. Finally, all isolates were tested for antimicrobial susceptibility against ampicillin, cephalotin, lincomycin, neomycin, penicillin, spiramycin and trimethoprim-sulphamethoxazole using the disk-diffusion technique. All isolates were amylase-positive and acetoin-negative, and failed to grow in 6.5% NaCl broth. Nine isolates were optochin-susceptible. Moreover, 10 isolates produced acid from mannitol, 21 produced acid from sorbitol, and 36 and 37 did not produce acid from salicin and trehalose, respectively. Six salicin- and trehalose-negative isolates and two mannitol- and sorbitol-fermenting isolates were found. Biochemical differences between serotypes were not observed. The most active drugs against S. suis were the beta-lactam antibiotics, although only 83.3%, 70% and 78.5% of isolates were susceptible to ampicillin, cephalotin and penicillin, respectively. Half of the isolates were resistant to trimethoprim-sulphamethoxazole, and resistance to lincomycin, neomycin and spiramycin appeared to be very high.

Abattoirs↗