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Biomedical subjects

P W Hansen

Publications and source records attributed to P W Hansen.

At least 19 recordsLinked to original sources
PubMed2001

An attempt to detect oestrus from changes in Fourier transform infrared spectra of milk from dairy heifers.

This study was carried out to investigate if there were systematic changes in milk Fourier transform infrared (FT-IR) spectra relative to stage of the oestrous cycle in cattle. Oestrous cycles of 22 lactating heifers were synchronized with two injections of prostaglandin F2alpha (PGF) administered 11 days apart. The heifers were milked twice daily, and milk samples were collected from each heifer at each milking for a period of 70 days, starting on the day of the second PGF injection. Oestrus was diagnosed by visual detection in conjunction with monitoring rectal temperature. Milk samples were analyzed by FT-IR spectroscopy and the spectra data were analyzed using partial least squares (PLS) methods in relation to time of observed oestrus in heifers. In this investigation, it was not possible to identify reliable changes in milk FT-IR spectra in relation to oestrus on a single heifer basis, though there was a weak correlation between FT-IR spectra and expected time of oestrus when the analysis was carried out across all the heifers.

Animals↗
PubMed1999

Detection of specific sugars in dairy process samples using multivariate curve resolution.

Dairy process monitoring by application of multivariate curve resolution using alternating least squares is presented. Alternating least squares was used for resolving Fourier transform infrared spectral data from a dairy batch process in which lactose is enzymatically hydrolyzed to glucose and galactose. It was possible to extract four compounds (fat, lactose, and two other sugar components) from the spectral data obtained from nine process runs. Subsequently, the pure spectra obtained in this way were used to monitor the content of these compounds in two new process runs. In this way, alternating least squares made it possible to follow the hydrolysis process by Fourier transform infrared spectroscopy without the need for reference analyses. When the results were correlated to reference results for lactose, the accuracy was similar to that obtained when a partial least squares regression was performed on the same data; lactose correlation was 0.980 when alternating least squares was used and was 0.987 when partial least squares was used.

Animals↗
PubMed1999

Screening of dairy cows for ketosis by use of infrared spectroscopy and multivariate calibration.

A fast and inexpensive method of screening ketosis in cows is presented. This method is based on the determination of acetone in bovine milk by using Fourier transform infrared spectroscopy combined with multivariate calibration. Only samples with a naturally increased acetone content could be used in the calibration step; samples containing added acetone did not produce an acceptable calibration equation. On test samples ranging from 0.0 to 2.8 mM acetone, an R2 of 0.81 and an accuracy (root mean square error of prediction) of 0.27 mM were obtained. This accuracy was sufficient to classify the cows into two groups: healthy and possibly ketotic. No false negatives were determined for the present data set.

Acetone↗
PubMed1995

An audiometric test battery for the evaluation of occupational exposure to industrial solvents.

Subjects exposed to various industrial solvents were evaluated with a test battery comprising both peripheral and central auditory tests. After otoscopy, all subjects underwent the following audiometric procedures: air- and bone-conduction in the conventional frequency range, air-conduction in the extended high-frequency range, speech recognition score, low-pass filtered speech recognition, stapedius reflex threshold, stapedius reflex decay, auditory brainstem response, and cognitive event-related responses. Apart from mild to moderate sensorineural hearing loss found in some of the subjects, the peripheral tests were normal in most subjects. The central tests (filtered speech and cognitive responses) showed varying degrees of abnormality which may reflect different levels of disease in this group of subjects.

Adult↗
PubMed1987

Cytotoxic human HLA class II restricted purified protein derivative-reactive T-lymphocyte clones. IV. Analysis of HLA restriction pattern and mycobacterial antigen specificity.

Human T-lymphocyte clones specific for antigenic components of purified protein derivative (PPD) of tuberculin were generated by limiting dilution using in vitro PPD-activated peripheral blood mononuclear cells from a single donor. The HLA restriction specificity of eight clones that were cytotoxic against autologous PPD-pulsed monocyte targets, was examined against a panel of allogeneic PPD pulsed targets. In agreement with our findings with bulk-expanded PPD-reactive cytotoxic T lymphocytes, all clones were restricted by HLA class II antigens: seven by HLA-DR 2 and one by HLA-DRw10--the other HLA-DR antigen of the donor. All clones were CD3+, CD4+, CD8-. One clone exhibited, in addition to HLA-DR2 restriction, unrestricted cytotoxic alloreactivity against HLA-DR1. In monoclonal antibody-blocking experiments the latter clone was the only one that was blocked. Its lytic ability was abolished by two monoclonal antibodies against monomorphic HLA-DR determinants. The antigen specificity of the clones was studied by using autologous monocyte targets pulsed with antigens prepared from a range of different mycobacterial species. All seven HLA-DR2-restricted clones reacted with the majority of antigens tested. In contrast, the HLA-DRw10-restricted clone reacted exclusively with an antigen unique to PPD.

Antibodies, Monoclonal↗
PubMed1986

Cell mediated PPD specific cytotoxicity against human monocyte targets: II. IL-2 expansion improves the strength and discriminatory power of CTLs used for cellular typing.

Large batches of Cytotoxic T Lymphocytes (CTLs) specific for antigenic components of Purified Protein Derivative of tuberculin (PPD) were generated from 20 donors. Peripheral Blood Mononuclear cells (PBM) were stimulated with PPD, expanded with Interleukin-2 (IL-2) and finally aliquotted and cryopreserved. It was found that CTLs could be cryopreserved without loss of activity, and compared to generating CTLs in primary culture alone, IL-2 expanded CTLs were stronger and discriminated better. To study their HLA restriction specificity, the CTLs were tested against a panel of 50 target cell donors using PPD pulsed monocytes as antigen presenting target cells. Reproducibility was examined by analysis of variance. Guided by the results, the mean value of 2 tests was selected as the basis for qualitative assignments.

Analysis of Variance↗
PubMed1986

Cell mediated PPD specific cytotoxicity against human monocyte targets: III. Cellular typing with CTLs restricted by class II HLA antigens.

The HLA-restriction specificity of a set of Cytotoxic T-Lymphocytes (CTLs) derived from 20 different individuals and with specificity for antigenic components in Purified Protein Derivative of tuberculin (PPD) were examined against a panel of 50 unrelated target cell donors. PPD pulsed monocytes were used as antigen presenting target cells. CTLs were generated by Interleukin-2 (IL-2) expansion of in vitro PPD activated Peripheral Blood Mononuclear Cells (PBM). The results confirm our previous finding that PPD-specific CTLs are restricted by HLA-class II - and not by class I antigens. The 20 CTLs used together provide reliable cellular typing reagents for the antigens HLA-DR2, -3, -4 and -7 and less so for the antigens HLA-DR1 and -5. In contrast, sharing between CTL- and target cell donors of HLA-DRw6 and -w8 correlates poorly to PPD-specific cytotoxicity. A few consistent exceptional patterns were observed. In one case lack of lysis in spite of HLA-DR antigen sharing could be explained by a split of HLA-DR2 into a normal and a short variant. Positive reactions in combinations, where no HLA-DR antigens are shared, were only few and evenly distributed among CTLs. Thus our findings indicate that our bulk CTLs predominantly contain clones restricted by determinants strongly associated to the serologically defined HLA-DR antigens.

Antigens, Surface↗
PubMed1985

Immunogenetic composition of 94 consecutive Danish families investigated with respect to bone marrow transplantation.

The immunogenetic composition of 94 patients needing bone marrow transplantation and their core families primarily investigated to select family bone marrow donors have been further analysed to test for association between disease and HLA-region markers. From this material it is shown, that in the primary immunogenetic analysis of the family, inclusion of mixed lymphocyte culture analysis increases donor possibilities by approximately 14% when a reciprocal negative MLC response and phenotypic HLA-DR compatibility are accepted as criteria for transplantation. Further, the results indicate, that no association between HLA and leukemia seems to exist.

ABO Blood-Group System↗
PubMed1984

Biochemical and cellular identification of HLA-Bw44 subtypes.

Biochemical analysis of HLA-Bw44 antigens by two-dimensional gelelectrophoresis and one-dimensional isoelectric focusing (IEF) from serologically heterozygous and homozygous donors allows the identification of two distinct types of HLA-Bw44 molecules, designated as Bw44-I and Bw44-II. These results are in concordance with the data obtained by CML-typing where at least two types of Bw44 target cells can be distinguished clearly as well. The antigen of type I has a more acidic isoelectric point (IEP) than that of type II. The difference in IEP are not due to differences in sialic acid content.

Female↗
PubMed1984

Evaluation of the acyclovir-induced modulation of the plaque-forming cell response of human peripheral blood lymphocytes.

The increasing use of the antiviral agent acyclovir has focused the attention to the possible side-effects on cellular and humoral immunological processes. The drug has preclinically been tested extensively but most investigations have been carried-out in animal models. The influence of acyclovir on the proliferation and the plaque-forming capability of pokeweed mitogen (PWM) activated cultures of unfractionated and isolated subpopulations from human peripheral blood lymphocytes (PBL), was investigated. These parameters were monitored with the 3H-thymidine incorporation technique and a protein A plaque-forming cell assay. Acyclovir had little inhibitory effect at physiological concentration whereas a detrimental decrease was noted at higher concentrations.

Acyclovir↗
PubMed1984

Cell-mediated PPD-specific cytotoxicity against human monocyte targets: evidence for restriction by class II HLA antigens.

Human Purified Protein Derivative of tuberculin- (PPD-) specific cytotoxic cells have been detected in cultures of peripheral blood mononuclear cells stimulated for 6 days with PPD. These cytotoxic cells are demonstrated by their ability to lyse PPD-pulsed autologous monocyte target cells, but not unpulsed targets. In a series of checkerboard experiments each involving 3-5 randomly combined donors, effector cells from 35 donors have been tested in autologous and 130 allogeneic combinations. Analysis of results from the pooled allogeneic combinations reveals that HLA-B - and even more pronounced HLA-DR - antigen sharing correlates positively to high lysis. No effect of HLA-A antigen sharing is found. A more detailed analysis shows that the effect of HLA-B sharing may be fully accounted for by HLA-B-DR linkage disequilibrium. The results thus indicate that cell-mediated PPD specific cytotoxicity is HLA-restricted. Further, the correlation to HLA-DR sharing indicates that the restriction element in this system in all probability is a class II antigen.

Cytotoxicity Tests, Immunologic↗
PubMed1983

Functional studies on lymphocytes from two siblings with congenital hypogammaglobulinaemia.

Two brothers with hypogammaglobulinaemia classified as common variable immunodeficiency (CVID) were investigated for distribution of peripheral blood lymphocyte (PBL) subpopulations, DNA synthesis and plaque-forming cell (PFC) capability of pokeweed mitogen (PWM) activated autologous and allogenic cocultures. Both patients had a decreased absolute number of T cells and normal or elevated levels of surface immunoglobulin (SmIg) bearing cells. Isolated B cells cocultured with autologous or allogeneic 4000 r irradiated T cells responded subnormally to PWM monitored by the 3H-thymidine incorporation in microcultures whereas B cells cocultured with allogeneic untreated normal T cells proliferated normally. PBL from parallel macrocultures of unfractionated or T/B separated patients' cells were not able to produce plaques using a reversed haemolytic protein A assay. Addition of glucocorticoid to unfractionated PBL did not reverse the unresponsiveness. In allogeneic cocultures patients' untreated or 2000 r irradiated T cells induced a normal PFC response. Normal untreated T cells induced a reduced number of IgM- and IgG-PFC from patients' B cells but this response was almost eliminated using irradiated normal T cells. These results demonstrate a primary B cell defect in the patients and indicate an impaired cooperation between patients' B and T cells. Activation of patients' B cells to Ig secretion requires the presence of proliferating T cells.

Agammaglobulinemia↗
PubMed1982

Activation of human alloreactive cytotoxic precursor T lymphocytes.

The requirements for allogeneic T-cell activation have been studied in experiments with T and/or B cells as stimulator. Although target determinants (TDs, defined by CTL effectors in CML) are present on B and T cells used as target cells, this study indicates that TDs are functionally different when expressed on B and T cells used as stimulator cells, as only B cells can activate CTL precursors. Further, the study confirms that inducing TDs and strong lymphocyte-activating determinants (LADs, defined by proliferation in MLC) can be distinct structures found on two different stimulator B cells. The study suggests that binding of cytotoxic precursor T cells to TDs per se does not allow any detectable activation or start of proliferation and differentiation but requires another function of the stimulator cells in the non-T-cell compartment. The nature of this function is unknown, but it is the background for the first signal received by the TD-specific clones of CTL precursors, resulting in the expression of growth receptors for T-cell growth factor or interleukin 2 which is the second signal necessary for clonal expansion and differentiation.

B-Lymphocytes↗
PubMed1982

Rapid enumeration of T lymphocytes by a flow-cytometric immunofluorescence method.

Combined with current advances in microprocessor-controlled flow cytometers, monoclonal antibodies provide a rapid means of phenotyping individual cell surface markers for a large number of clinical samples accurately and reproducibly, which may provide useful information in diagnosing disease and monitoring patients. We have developed a one-step flow-cytometric immunofluorescence procedure for enumerating E-rosette lymphocytes from whole blood by using the monoclonal antibody OKT11. This antibody recognizes the sheep erythrocyte receptor on the lymphocyte surface and can block sheep E-rosette formation. The flow cytometer we use, an Ortho Spectrum III, distinguishes lymphocytes from other leukocytes by measuring the narrow forward and right-angle light-scattering properties of the cells. The instrument further differentiates T lymphocytes frm non-T lymphocytes by measuring the green fluorescence signal of the OKT11-positive lymphocytes. In a typical sample, 1500--2500 lymphocytes are counted in 25 s. In a study of 158 patient samples, ranging from 1% to greater than 90% E-rosette-positive lymphocytes, the correlation coefficient between the manual E-rosette count and the flow immunofluorescence measurement is 0.943.

Antibodies, Monoclonal↗
PubMed1980

Isolation of human T and B lymphocytes by E-rosette gradient centrifugation. Characterization of the isolated subpopulations.

Some methodological aspects of E-rosette gradient centrifugation for separation of human B and T lymphocytes are described. Treatment of sheep red blood cells (SRBC) with 2-aminoethylisothiouronium bromide (AET) accelerates and enhances E-rosette formation providing an effective and time saving method which takes less than 2 h to perform. Depletion of E-rosette forming cells (E-RFC) is almost complete, leaving less than 1% of the initial E-RFC at the interphase layer. By use of the lymphocyte donor's autologous serum containing naturally occurring anti-SRBC antibody and complement the SRBC in the rosetted T lymphocyte fraction are easily and completely lysed without damage to the lymphocytes. This procedure is shown to have little effect on the properties of the isolated T cells. The isolated lymphocyte subpopulations have been characterized by tests for lymphocyte and monocyte markers.

B-Lymphocytes↗