Biomedical subjects

P S Paul

Publications and source records attributed to P S Paul.

At least 19 recordsLinked to original sources

PubMed2006

Abnormal spatial selection and tracking in children with amblyopia.

We assessed 18 children with unilateral amblyopia and 30 age-matched controls on one low-level and three high-level motion tasks. Children with amblyopia showed similar performance to controls in both amblyopic and fellow eyes on a low-level global motion task and on a high-level 2-dot apparent motion task. Performance on both single-object and multiple-object attentive tracking tasks was significantly depressed in both amblyopic and fellow eyes relative to controls. These findings suggest that binocular regions of posterior parietal cortex likely contribute to a deficit in voluntary, spatial attention that is a component of amblyopia.

Adolescent↗

PubMed2005

An epidemiological study of injury in mines: implications for safety promotion.

The role of various factors in coal mine-related injuries was investigated using a case-control design. The study setting was two neighbouring underground coal mines in India. Cases comprised mine workers (n = 150) who had sustained a prior mine-related injury from a population of 1000 underground workers. Controls were selected from those mineworkers with no history of a prior mine-related injury using frequency matching (n = 150) from the same source population. Data were collected from the cases and controls using a structured survey questionnaire. Based on the responses of the participants, each factor was grouped into three categories. High-low plots and Chi-square tests were conducted to explore the differences between the cases and controls. Bivariate logistic regression was run to estimate the crude odds of injuries, while multivariate logistic regression estimated the adjusted odds of injuries to the workers for the various variable categories. High-low plots and the Chi-square test clearly revealed that the cases and controls significantly differed in their responses for the variables studied. Accident-involved workers take more risks, are negatively affected, job dissatisfied, feel more production pressure, job stress, work hazards and are less job involved and are more dissatisfied with safety environment and social climate of the mines compared to the controls. The multivariate odds of injuries to high risk taking, negatively affected and job dissatisfied workers are 1.21, 9.34 and 2.00 times more compared to their lowest counterparts. Similarly, workers satisfied with the overall safety practice and safety equipment availability and maintenance are 1.5 and 3.12 times less likely to be injured than the workers with little or no satisfaction with the above factors. It is therefore concluded that negative affectivity and job dissatisfaction are the two major personal level factors that contribute more towards accident/injury in the mines studied. Identification and elimination/reduction of negative attitudes are of utmost importance.

Accidents, Occupational↗

PubMed2003

Pathogenicity of three isolates of porcine respiratory coronavirus in the USA.

The pathogenicity of three isolates of porcine respiratory coronavirus (AR310, LEPP and 1894) from the USA was assessed in specific pathogen-free pigs. Pigs inoculated with 1894 developed mild respiratory disease and pigs inoculated with AR310 and LEPP developed moderate respiratory disease from four to 10 days after they were inoculated, but all the pigs recovered fully by 14 days after inoculation. Gross and microscopic examination revealed mild (1894) to moderate (AR310 and LEPP) multifocal bronchointerstitial pneumonia from four to 10 days after inoculation. The lesions were characterised by necrotising bronchiolitis, septal infiltration with mononuclear cells, and a mixed alveolar exudate. No clinical signs or microscopic lesions were observed in control pigs that had not been inoculated.

Animals↗

PubMed2003

Exogenous porcine viruses.

Porcine organs, cells and tissues provide a viable source of transplants in humans, though there is some concern of public health risk from adaptation of swine infectious agents in humans. Limited information is available on the public health risk of many exogenous swine viruses, and reliable and rapid diagnostic tests are available for only a few of these. The ability of several porcine viruses to cause transplacental fetal infection (parvoviruses, circoviruses, and arteriviruses), emergence or recognition of several new porcine viruses during the last two decades (porcine circovirus, arterivirus, paramyxoviruses, herpesviruses, and porcine respiratory coronavirus) and the immunosuppressed state of the transplant recipients increases the xenozoonoses risk of humans to porcine viruses through transplantation. Much of this risk can be eliminated with vigilance and sustained monitoring along with a better understanding of pathogenesis and development of better diagnostic tests. In this review we present information on selected exogenous viruses, highlighting their characteristics, pathogenesis of viral infections in swine, methods for their detection, and the potential xenozoonoses risk they present. Emphasis has been given in this review to swine influenza virus, paramyxovirus (Nipah virus, Menagle virus, LaPiedad paramyxovirus, porcine paramyxovirus), arterivirus (porcine reproductive and respiratory syndrome virus) and circovirus as either they represent new swine viruses or present the greatest risk. We have also presented information on porcine parvovirus, Japanese encephalitis virus, encephalomyocarditis virus, herpesviruses (pseudorabies virus, porcine lymphotropic herpesvirus, porcine cytomegalovirus), coronaviruses (TGEV, PRCV, HEV, PEDV) and adenovirus. The potential of swine viruses to infect humans needs to be assessed in vitro and in vivo and rapid and more reliable diagnostic methods need to be developed to assure safe supply of porcine tissues and cells for xenotransplantation.

Animals↗

PubMed2002

Effects of different us isolates of porcine reproductive and respiratory syndrome virus (PRRSV) on blood and bone marrow parameters of experimentally infected pigs.

Seventy five-week-old, crossbred, caesarean-derived, colostrum-deprived pigs were randomly divided into five groups of 14 pigs and assigned one of five treatments: the intranasal inoculation of 1 (5.7) TCID50 of one of four plaque-purified isolates of porcine reproductive and respiratory syndrome virus (PRRSV) (VR2385, VR2431, ISU-984 and ISU-22), or uninfected cell culture and media. Haematological variables were measured for 21 days and bone marrow was analysed when the pigs were killed three, seven, 10, 21 or 28 days after the inoculation. The PRRSV-infected pigs had non-regenerative anaemia and markedly increased myeloid:erythroid ratios from three to 21 days after inoculation. There was a significant (P < 0.05) difference in the severity of the anaemia induced by the four PRRSV isolates; the most highly pneumovirulent strains (VR2385, ISU-984 and ISU-22) induced more severe anaemia than the least virulent isolate (VR2431). The anaemia induced by PRRSV was probably due to a direct or indirect effect on erythroid precursor cells in the bone marrow.

Anemia↗

PubMed2002

Survey of porcine rotavirus G and P genotype in Poland and the United States using RT-PCR.

Porcine rotaviruses are a common cause of gastroenteritis. Several serotypes have been detected based on the two surface proteins VP4 (P-types) and VP7 (G-types). However, limited studies have been performed on the relative frequency of rotavirus types in diarrhetic pigs primarily because of the lack of availability of suitable methods. In this study, we describe a reverse transcriptase-polymerase chain reaction (RT-PCR) method for the typing of P and G types of rotavirus. This method allowed to detect G and P types in 96.8 and 87.1% of isolates collected in the United States, respectively and in 54.5 and 38.6% of isolates collected in Poland, respectively. Within the US specimens the G3, G4, G5, G9 and G10 types were detected in combination with P6 and P7 types while among Polish specimens only G3, G4 and G5 types in combination with P6 and P7 types were identified. In both instances the G4 and G5 were the most prevalent types. These studies show that a RT-PCR typing method is suitable for molecular epidemiological studies and that there is more diversity among porcine rotavirus than previously reported.

Animals↗

PubMed2001

Double in situ hybridization for simultaneous detection of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus (PCV).

A double in situ hybridization method for the simultaneous detection of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus (PCV) genomes in the same tissue section was applied to lung tissues from 9 pigs in which PRRSV and PCV coinfection had been previously demonstrated. Paraffin-embedded tissue sections were simultaneously hybridized with a digoxigenin-labeled antisense RNA probe for PRRSV and a fluorescein-labeled antisense RNA probe for PCV, and hybridization was detected with anti-digoxigenin alkaline phosphatase/fast red and anti-fluorescein peroxidase/diaminobenzidine, respectively. PRRSV and PCV genomes were identified in the same pulmonary cell types as reported previously in all 9 pigs. In all pigs, PCV-positive cells outnumbered PRRSV-positive cells. A small proportion of alveolar macrophages contained both PRRSV and PCV genomes.

Animals↗

PubMed2001

Comparison of porcine reproductive and respiratory syndrome virus growth in media supplemented with fetal bovine serum or a serum replacement.

Commercially available serum replacements are often used in cell culture as a cheaper and less variable substitute for fetal bovine serum (FBS). The growth of porcine reproductive and respiratory syndrome virus (PRRSV) isolates in CRL11171 cells maintained in a medium supplemented with FBS was compared with virus propagation in the same cell line maintained in the same medium with a serum replacement. The PRRSV replicated significantly better when the cell culture medium was supplemented with FBS. The results of this study have implications for the use of serum replacement-supplemented medium for PRRSV diagnosis by virus isolation.

Animals↗

PubMed2001

Paramyxovirus infection in pigs with interstitial pneumonia and encephalitis in the United States.

In the last few years, newly recognized paramyxoviruses have been associated with severe disease in several animal species, including swine, as well as in human beings. Recently, a paramyxovirus was isolated from a swine herd in the northcentral United States that experienced an epizootic of respiratory and central nervous system disease. Affected pigs had interstitial pneumonia with necrotizing bronchiolitis and encephalitis characterized by lymphocytic perivasculitis and diffuse gliosis. Germ-free pigs inoculated with this isolate developed mild clinical illness and similar but less severe histopathologic lesions in lungs and brain.

Animals↗

PubMed2001

Experimental reproduction of severe disease in CD/CD pigs concurrently infected with type 2 porcine circovirus and porcine reproductive and respiratory syndrome virus.

Three-week-old cesarean-derived colostrum-deprived (CD/CD) pigs were inoculated with porcine circovirus type 2 (PCV2, n = 19), porcine reproductive and respiratory syndrome virus (PRRSV, n = 13), concurrent PCV2 and PRRSV (PCV2/PRRSV, n = 17), or a sham inoculum (n = 12) to compare the independent and combined effects of these agents. Necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. By 10 dpi, PCV2/PRRSV-inoculated pigs had severe dyspnea, lethargy, and occasional icterus; after 10 dpi, mortality in this group was 10/11 (91%), and all PCV2/ PRRSV-inoculated pigs were dead by 20 dpi. PCV2-inoculated pigs developed lethargy and sporadic icterus, and 8/19 (42%) developed exudative epidermitis; mortality was 5/19 (26%). PRRSV-inoculated pigs developed dyspnea and mild lethargy that resolved by 28 dpi. Microscopic lesions consistent with postweaning multisystemic wasting syndrome (PMWS) were present in both PCV2- and PCV2/PRRSV-inoculated pigs and included lymphoid depletion, necrotizing hepatitis, mild necrotizing bronchiolitis, and infiltrates of macrophages that occasionally contained basophilic intracytoplasmic inclusion bodies in lymphoid and other tissues. PCV2/ PRRSV-inoculated pigs also had severe proliferative interstitial pneumonia and more consistent hepatic lesions. The most severe lesions contained the greatest number of PCV2 antigen-containing cells. PRRSV-inoculated pigs had moderate proliferative interstitial pneumonia but did not develop bronchiolar or hepatic lesions or lymphoid depletion. All groups remained seronegative to porcine parvovirus. The results indicate that 1) PCV2 coinfection increases the severity of PRRSV-induced interstitial pneumonia in CD/CD pigs and 2) PCV2 but not PRRSV induces the lymphoid depletion, granulomatous inflammation, and necrotizing hepatitis characteristic of PMWS.

Animals↗

PubMed2000

Validation of a reverse transcriptase multiplex PCR test for the serotype determination of U.S. isolates of bluetongue virus.

Bluetongue (BT) is an arthropod-borne viral disease affecting ruminants primarily in tropical and temperate regions of the world. Of the 24 serotypes of BT virus (BTV) identified worldwide, five have been found in the United States. Serotype identification of BTV isolates is important to the epidemiology of the virus, but current methods are cumbersome. A single-tube multiplex reverse transcriptase polymerase chain reaction (mRT-PCR) assay, previously developed for the serotype determination of U.S. BTV isolates, was evaluated. The determination of serotype was based on the size of the resultant amplified product. The procedure was evaluated using all 24 serotypes of BTV and nine serotypes of epizootic hemorrhagic disease virus (EHDV), a closely related orbivirus. Only the five U.S. serotypes of BTV were detected by the mRT-PCR. The assay was further tested using 132 BTV isolates originating from 24 western and southern states of the United States, from several different host species, spanning a period of 24 years. The serotypes of the isolates were determined by both a virus neutralization (VN) procedure and the mRT-PCR. Comparison of the mRT-PCR to the standard VN showed that the mRT-PCR successfully identified the serotypes of 130 of the isolates and was shown to be more reliable and specific than the VN assay.

Animals↗

PubMed2000

Development of probes to differentiate porcine circovirus types 1 and 2 in vitro by in situ hybridization.

Porcine circovirus type 1 (PCV1), a PK-15 cell line contaminant, and porcine circovirus type 2 (PCV2), associated with post-weaning multisystemic wasting syndrome (PMWS), are genetically and antigenically related. Several techniques have been developed to detect PCV, including in situ hybridization (ISH). Previously reported probes used for ISH may hybridize with both PCV1 and PCV2 nucleic acids. We attempted to produce probes for ISH that can detect and differentiate PCV2 from PCV1 in PCV-infected cells. Riboprobes were synthesized from the sense and antisense strands of both open reading frames 1 and 2 (ORF1 and ORF2) of PCV2. At 42 and 58 degrees C, the ORF1 antisense probe hybridized with nucleic acid from both PCV1- and PCV2-infected cells. At 58 degrees C, the ORF2 antisense probe hybridized with PCV2 nucleic acid but not with PCV1 nucleic acid. The ORF1 and ORF2 sense probes bound only with PCV2 nucleic acid. Both antisense strand probes produced stronger signals than the sense strand probes. The results showed that the PCV2 ORF1 antisense probe is the most likely probe to detect both PCV types while the ORF2 antisense probe is capable of discriminating between PCV1 and PCV2.

Animals↗

PubMed2000

Utilization of a rate enhancement hybridization buffer system for rapid in situ hybridization for the detection of porcine circovirus in cell culture and in tissues of pigs with postweaning multisystemic wasting syndrome.

A rapid in situ hybridization (ISH) technique for the detection of porcine circovirus (PCV) nucleic acid in cell culture and formalin-fixed paraffin-embedded tissues was developed. A fluorescein-labeled RNA probe was transcribed from a plasmid containing 530 bp of the ORF1 of a PCV isolated from a pig with postweaning multisystemic wasting syndrome (PMWS). Hybridization using standard hybridization buffer was performed at 42 C for 16 hours and was compared to hybridization using rate enhancement hybridization (REH) buffer at 67 C for 2 hours. Hybridization was detected with an alkaline phosphatase-conjugated antifluorescein antibody. In both cultured cells and tissues from pigs with PMWS, the signal intensity and number of labeled cells in sections hybridized with REH buffer were equal to those of sections hybridized with standard hybridization buffer. The total time required for ISH using the REH buffer is 7-8 hours, thus making this protocol suitable for application in routine PCV diagnosis.

Animals↗

PubMed1999

Development of a polyclonal-antibody-based immunohistochemical method for the detection of type 2 porcine circovirus in formalin-fixed, paraffin-embedded tissue.

An immunohistochemical method for the detection of type 2 porcine circovirus (PCV2) in paraffin-embedded tissue was developed. Rabbits were inoculated with purified PCV2 to obtain a polyclonal antiserum. Antiserum was applied to sections of porcine tissue that contained lesions consistent with postweaning multisystemic wasting syndrome and in which PCV2 genome had been demonstrated by in situ hybridization. In all cases (18/18), the density and distribution of positive cells detected by in situ hybridization or immunohistochemistry were identical. The immunohistochemical method is more rapid and less expensive than in situ hybridization and is thus more suitable for routine diagnostic use.

Animals↗

PubMed1998

Transmissible gastroenteritis virus induced apoptosis in swine testes cell cultures.

Transmissible gastroenteritis virus (TGEV) is a coronavirus which causes severe gastroenteritis and atrophy of intestinal villous epithelial cells in piglets. However, the mechanism of cell death caused by TGEV is not known. In this study, we report that TGEV induces cell death by apoptosis. TGEV-induced apoptosis was demonstrated by agarose gel electrophoresis, electron microscopy, and terminal deoxytransferase digoxigenin-dUTP nick end labeling (TUNEL). Double labeling experiment confirmed the result from electron microscopy and showed that most of the apoptotic cells were bystander cells as they were negative for TGEV nucleic acids. Results of this study indicate that TGEV induces apoptosis in vitro and that most of the cells undergoing apoptosis are bystander cells, thus amplifying the cytopathic effect of TGEV.

Animals↗

PubMed1998

Monoclonal antibodies against conformationally dependent epitopes on porcine reproductive and respiratory syndrome virus.

Monoclonal antibodies (MAbs) against porcine reproductive and respiratory syndrome virus (PRRSV) were prepared and characterized. Four MAbs were developed from the mice immunized with the recombinant GP4 protein expressed in insect cells, and six MAbs were derived from the immunization with recombinant GP5 protein. All of the MAbs showed strong perinuclear fluorescence in PRRSV VR2385 infected cells by immunofluorescence staining. Among the MAbs to GP5 protein, one showed strong reactivity in ELISA and recognized a 26 kDa band of PRRSV in a western blot assay, while another showed neutralizing activity against the VR2385 isolate. Out of the four MAbs to GP4 protein, one showed mild reactivity in ELISA with detergent extracted antigen, but had no reactivity in a western-blot assay. The failure of MAb binding to detergent extracted antigen in ELISA or in western-blot analysis indicated that the MAbs were against conformationally dependent epitopes. Reactivity patterns of the MAbs with PRRSV field isolates tested by fixed-cell ELISA showed that there are antigenic variations in PRRSV GP4 and GP5 proteins. Development of these MAbs will benefit further studies on PRRSV structural proteins as well as in understanding their roles in PRRSV pathogenesis.

Animals↗

PubMed1998

A pneumo-virulent United States isolate of porcine reproductive and respiratory syndrome virus induces apoptosis in bystander cells both in vitro and in vivo.

Evidence of apoptosis was detected for the United States porcine reproductive and respiratory syndrome virus (PRRSV) in ATCC CRL11171 cells inoculated with strain ATCC VR2385 and in the tissues of pigs infected with the same strain. Apoptosis was detected by agarose gel electrophoresis, transmission electron microscopy and terminal deoxytransferase dUTP nick end labelling (TUNEL) techniques. By electron microscopy and double-labelling techniques, apoptosis was detected primarily in uninfected bystander cells in the continuous cell line rather than the PRRSV-infected cells. In the lungs, the apoptotic cells were predominantly alveolar and pulmonary intravascular macrophages, and mononuclear cells in the alveolar septa. In the lymph nodes, the apoptotic cells were predominantly tingible body macrophages and mononuclear cells. The induction of apoptosis in a large number of mononuclear cells in the lungs and lymph nodes appears to be a mechanism of PRRSV pathogenesis and might be an explanation for a dramatic reduction in the number of alveolar macrophages and circulating lymphocytes and monocytes in PRRSV-infected pigs.

Animals↗

PubMed1998

Detection of a novel strain of porcine circovirus in pigs with postweaning multisystemic wasting syndrome.

Swine infectious agents, especially viruses, are potential public health risks associated with the use of pig organs for xenotransplantation in humans. Therefore, there is a need for better characterization of swine viruses and for the development of diagnostic tests for their detection. We report here isolation of a novel strain of porcine circovirus (PCV) from pigs with postweaning multisystemic wasting syndrome (PMWS). Affected pigs exhibited severe interstitial pneumonia and lymphoid depletion. The complete nucleotide sequence (1,768 nucleotides) of the genome of the PCV isolate was determined and compared with the sequence of the PCV strain isolated from PK-15 cells. Sequence comparison revealed significant differences between the two PCV strains, with an overall DNA homology of 76%. Two major open reading frames (ORFs) were identified. ORF1 was more conserved between the two strains, with 83% nucleotide homology and 86% amino acid homology. ORF2 was more variable, with nucleotide homology of 67% and amino acid homology of 65%. PCR and in situ hybridization demonstrated abundant viral DNA in various organs of pigs with PMWS. In situ hybridization demonstrated that this strain of PCV targets multiple organs and infects macrophages, lymphocytes, endothelial cells, and epithelial cells.

Amino Acid Sequence↗