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Biomedical subjects

R A Knight

Publications and source records attributed to R A Knight.

At least 181 records · Page 10Linked to original sources
PubMed1978

Experimental cross infections of Fasciola hepatica in lambs and calves.

The effects of experimental infections with Fasciola hepatica of ovine and bovine origin in homologous and heterologous hosts and in uninfected controls were compared; groups comprised 5 animals each. The effects of the infections were monitored by biweekly determinations of packed cell volumes (PCV), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), gamma glutamyl transpeptidase (GGT), serum iron, bilirubin levels, alkaline phosphatase (AlP) and total serum protein levels. Infected animals showed changes in SGOT, SGPT and GGT activity levels, and GGT activity levels, and infected lambs showed changes in PCV and AlP. However, no no significant differences in these serum levels between infected host groups were attributable to fluke strain. At necropsy, calves infected with ovine and bovine strains on an average had about the same number of flukes, but lambs infected with a high dose of the bovine strain on the average had nearly twice the number of flukes as those infected with ovine strain. Weight gains did not differ within host groups; liver damage was extensive in all infected animals. On the basis of these experiments, the pathogenicity of the ovine and the bovine strains of F. hepatica appears to be the same.

Alanine Transaminase↗
PubMed1977

Overinclusion, broad scanning, and picture recognition in schizophrenics.

Difficulty of picture and word recognition was manipulated to test the hypothesis that schizophrenics have adequate recognition memories and to determine whether overinclusion is related to a good visual recognition memory. Good and poor premorbid, acute and chronic schizophrenics were compared to nonpsychotic psychiatric patients and to hospital aides. Both Payne's Object Classification Test and Goldstein-Scheerer's Object Sorting Test were given to all the patients, but only the former differentiated among the diagnostic subgroups and was related to good picture memory. When the measures of overinclusion, chronicity, premorbidity and intelligence were used as independent variables in a multiple regression, only Payne NonA predicted success on the picture task. Good premorbid schizophrenics recognized pictures as well as normals and nonpsychotics, but poor premorbids' picture memory was significantly worse. No experimental variable predicted word performance in a multiple regression, and good premorbids did not differ from poor premorbids on their word recognition. The authors favored the interpretation that the pattern of performance of overinclusive schizophrenics reflects their tendency to scan broadly both important and unimportant features of stimuli.

Acute Disease↗
PubMed1977

The interrater reliability of the Psychotic Inpatient Profile.

The interrater reliabilities of the 12 scales of the Psychotic Inpatient Profile (PIP) were assessed in three independent samples. These reliabilities were found to be consistently low for the three samples. Several possible sources of low reliability were investigated, and evidence to support the hypothesis that consistent rater biases might have contributed to this low reliability was found. The authors make several suggestions of ways to improve PIP's reliability.

Adjustment Disorders↗
PubMed1977

Schizophrenics' responses to autonomous and experimenter-controlled conditions.

Four groups of hospitalized VA patients were administered a reaction time task in which the conditions of stimulus presentation varied from subject autonomy to experimenter control. Questionnaires were administered to assess patients' self-reports of locus of control (Rotter's I-E scale) and their perceptions of their mothers' child rearing attitudes (Schaefer's CRPBI). Reaction times of chronic schizophrenics were significantly slower than poor and good premorbid acute schizophrenics and nonpsychotics, and the poor but not the good premorbids were significantly slower than the nonpsychotics. The autonomy-control manipulations produced a trend supporting the finding of Cromwell et al. that chronic schizophrenics perform best in an experimenter-controlled condition whereas nonpsychotics do best in an autonomous condition. Variation of these treatments, however, caused no differences in acute schizophrenics' task performance. When examined together, the reaction time and questionnaire findings suggest that autonomy and generalized locus of control are not salient factors in explaining schizophrenic performance deficit.

Adolescent↗
PubMed1977

Albendazole as a fasciolicide in experimentally infected sheep.

The new drug albendazole (methyl [5-(propylthio)-1H-benzimidazol-2-yl]carbamate) was tested in 90 sheep experimentally infected with Fasciola hepatica. Dose rates of 10, 15, and 20 mg/kg of body weight were active against adult flukes, with efficacies of 98, 95, and 100% respectively. The drug was less active against immature F hepatica at 3 weeks after sheep were inoculated. The drug given at dose rates of 20, 30, 40, and 50 mg/kg had efficacies 24, 47, 63, and 76%. Flukes were not found at posttreatment hour 48 in bile ducts of sheep given a dose of 20 mg/kg. Evidence of drug toxicity was not seen.

Animals↗
PubMed1975

Studies on a gross-virus-induced lymphoma in the rat. II. The role of cell-membrane-associated and serum P30 antigen in the antibody and cell-mediated response.

The internal viral protein, p30-1, has been identified by cytotoxicity tests using xenogeneic sera, on MuLV-G-induced rat lymphoma cells. In this system internal virion antigens, and in particular p30, are cytotoxic target antigens for syngeneic antibody and cell-mediated cytotoxicity; p30 is also present in the serum of rats with progressively growing lymphomas, and is the principal antigen responsible for the inhibition of cell-mediated cytotoxicity produced by these sera.

AKR murine leukemia virus↗
PubMed1975

Cell-mediated immunity to moloney sarcoma virus in mice. I. Analysis of antigens responsible for lymphocyte stimulation in regressor mice.

Purified viruses, viral antigens, and cell extracts have been tested for their ability to stimulate protein synthesis by MSV-M-1 regressor spleen cells from BALB/c mice. Immune, but not normal cells, responded to MSV-M, but not to MSV-G virus-1, and to the type-specific viral envelope glycoprotein from MSV-M virus. Extracts of mouse embryo fibroblasts transformed by either MSV-M or MSV-G, however, specifically stimulated MSV-M regressor spleen cells. Cells stimulated by different antigens, and by phytohaemagglutinin, had the same sedimentation profile and were identified as T-lymphocytes.

Animals↗
PubMed1975

Cell-mediated immunity to Moloney sarcoma virus in mice. II. Analysis of antigenic specificities involved in T lymphocyte-mediated in vivo rejection of murine sarcoma virus-induced tumors.

Sublethally irradiated BALB/c mice innoculated with Moloney sarcoma virus (MSVm) develop progressively growing tumors and die within 30 days of virus innoculation. These animals can be protected from tumor progression (and death) by innoculation of small numbers of MSV-immune T lymphocytes from MSV-M innoculated (but unirradiated) animals. T lymphocytes in these donor animals have been shown to express immunity to a variety of viral and virally-induced antigens. We have investigated whether immunity to any one of these antigens was critically important in leading to protection of the irradiated animals by sensitizing normal T lymphocytes in vitro to different viral antigens and examining the ability of these sensitized cells to protect the irradiated recipients. Data is presented to show that cells sensitized in vitro to MSV-transformed fibroblasts, and to purified antigens with group specificity, but not to viral envelope antigens, or whole virus, are capable of protecting the irradiated MS innoculated animals.

Animals↗
PubMed1975

Immunity to murine sarcoma virus induced tumours. IV. Direct cellular cytolysis of 51Cr labelled target cells in vitro and analysis of blocking factors which modulate cytotoxicity.

The antigen specific cell mediated cytotoxicity of MSV immune spleen lymphocytes to 51Cr labelled murine lymphoma cells was wholly abolished by pretreatment of the spleen cells with anti-theta antibody and complement. Early during the immune response to MSV the cytotoxic acitivity was inhibited by incubation of immune lymphocytes with "late progressor" or "early regressor" serum. Immune lymphocytes at later times were more refractory to such inhibition by serum blocking factors. Although unfractionated cytotoxic lymphocytes, irrespective of the time after MSV infection at which they were tested, were inhibited by soluble tumour associated antigen (TAA), a subpopulation of cytotoxic T cells was identified which was inhibited neither by antigen nor serum.

Animals↗
PubMed1975

Studies on mouse Moloney virus induced tumours: I. The detection of p30 as a cytotoxic target on murine Moloney leukaemic spleen cells, and on an in vitro Moloney sarcoma line by antibody mediated cytotoxicity.

Antigenic determinants of p30, the most abundant internal virion protein of C type RNA viruses, were detected on the surface of spleen cells from mice bearing Moloney leukaemia and on an in vitro line of Moloney sarcoma, MSC. On both cell types, these determinants on the p30 molecules served as cytotoxic targets in a xenogenic complement dependent antibody mediated 51Cr release assay. Two antisera were used: a rat anti MLV -M induced lymphoma serum, and an antiserum raised in goats to either disrupted FeLV. The cytotoxic target antigens of these antisera were analysed by inhibition of cytotoxicity with viral and cellular proteins.

Animals↗
PubMed1975

Studies on mouse Moloney virus induced tumours: II. Detection of p30 in the serum of mice with Moloney leukaemia by in vitro blocking of complement dependent antibody mediated cytotoxicity.

Sera from Balb/c mice bearing Moloney leukaemia block complement dependent antibody mediated cytotoxicity of an antiserum prepared in rats against syngeneic Moloney virus induced lymphomata when either spleen cells from mice bearing Moloney leukaemia (M) or an in vitro line of Moloney virus transformed cells (MSC) are used as targets. This antiserum has been shown to recognize p30, the major internal virion protein, as a cytotoxic target on these cells. Viral particles were identified by electron microscopic examination of pelleted material obtained from leukaemic sera after high speed centrifugation. However, removal of virus did not affect the capacity of the leukaemic sera to absorb cytotoxicity of rat ILR-3 for MSC targets, and only depressed somewhat its ability to absorb activity of the same antisera against M targets. Virus-free leukaemic sera also blocks complement dependent antibody mediated cytotoxicity of an antiserum prepared in goats against the gs3 determinant of p30. This indicates that the material in leukaemic sera responsible for the in vitro block of antibody mediated cytotoxicity was p30. A lesser degree of block was observed with sera obtained from normal Balb/c mice, but the nature of material responsible is as yet undefined.

Animals↗
PubMed1975

Comparison of the germicidal activity of prepodyne and betadine surgical scrub solutions.

Two iodophoric surgical scrubs soaps, Prepodyne and Betadine, were evaluated for bacteriocidal activity in a modified phenol coefficient test. A standard inoculum of each of 18 species of microorganisms was mixed with a 1:8 dilution of each iodophor and subcultured after one, three, and five minutes of exposure. Complete cidal activty was exhibited by both Prepodyne and Betadine. Twenty-five subjects were tested in hand washing experiments using Betadine and Prepodyne surgical scrub solutions. Quantitative fingerprint cultures were obtained before and after hand washing. Betadine resulted in an 85.2 per cent plus or minus 24 per cent decrease; Prepodyne, and 83.6 per cent plus or minus 21 per cent decrease. It can'be concluded from this data that there is no difference in bacteriocidal effectiveness between the two scrub soaps.

Acinetobacter↗