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Biomedical subjects

T M Phillips

Publications and source records attributed to T M Phillips.

139 records · Page 8Linked to original sources

Autoimmunization with irradiated tumour cells in human malignant melanoma.

Thirteen patients have been immunized with their own irradiated melanoma cells on one or more occasions. Following these autografts tumour-specific cytotoxic antibodies were produced, the longest response lasting 14 days. This procedure had no apparent effect on the course of the disease in these patients.

Adult↗

Tumour-specific antibodies in human malignant melanoma and their relationship to the extent of the disease.

Biopsy specimens and sera were obtained from 103 melanoma patients. Autoantibodies were demonstrated by (1) complement-dependent cytotoxicity of autologous melanoma cells in short-term culture; (2) complement-dependent inhibition of ribonucleic acid synthesis; (3) immunofluorescent staining of the cytoplasm of killed melanoma cells and of the surface membrane of viable melanoma cells. Over one-third of the sera studied had antibodies to autologous melanoma cells. Although for technical reasons all three tests could not be performed with the cells from every melanoma, whenever multiple testing was possible there was complete concordance. The autoantibodies were virtually confined to patients in whom the disease was not widely disseminated, and over 80% of such patients had positive sera. In a limited number of patients who have been followed autoantibodies disappeared as the disease progressed to become widely disseminated. Two patients with generalized disease developed autoantibodies following inoculation by their own irradiated tumour cells.TWO TYPES OF AUTOANTIBODIES WERE RECOGNIZED: one, active against antigen(s) in the cell surface membrane, was specific for each tumour-that is, only the autologous serum reacted-and was concerned in the cytotoxic activity; the other reacted with cytoplasmic antigens which appeared to be present in most or all melanoma cells.

Autoantibodies↗

Measurement of bioactive neuropeptides using a chromatographic immunosensor cartridge.

Neuropeptide modulation of host defenses is associated with a number of clinical conditions in which tissue injury is caused by a process termed neurogenic inflammation. Monitoring of neuropeptide activity during both disease episodes and therapy has proven difficult due to a lack of correlation between laboratory evaluations and disease activity. Although a number of assays are available for measuring the total neuropeptide content of tissue samples, few can measure the bioactive component which is the more physiologically accurate parameter. In an attempt to overcome this problem, a receptor-affinity chromatographic technique coupled with immunological detection has been developed for measuring three bioactive neuropeptides (substance P, vasoactive intestinal peptide, and calcitonin gene-related peptide) in tissue biopsy extracts. The technique involves isolation of the active neuropeptides via their ability to bind to immobilized receptors followed by measurement of the bound materials by a series of simultaneous immunoassays. The techniques compares favourably with results obtained using conventional bioassays and has the added advantage that multiple analytes can be measured in a single procedure.

Biosensing Techniques↗

Measurement of total and bioactive interleukin-2 in tissue samples by immunoaffinity-receptor affinity chromatography.

The detection and measurement of cytokines is an important issue in the clinico-pathological diagnosis of several clinical entities, including organ transplant rejection. Existing techniques, although sensitive, measure only total cytokine concentrations and cannot measure bioactivity. A chromatographic system combining immunoaffinity chromatography with an immobilized receptor detection cartridge has been developed for measuring total and bioactive interleukin (IL)-2 concentrations in tissue extracts prepared from biopsy materials taken from renal transplant recipients during both rejection and drug-induced nephrotoxic episodes. The technique employs a short high-pressure chromatography column packed with antibody-coated glass beads for the initial analyte separation and concentration, followed by detection of bioactive molecules through their interactions with specific, immobilized receptors. This system compares favourably with both conventional bioassays and immunoassays for measuring IL-2 in tissue samples.

Animals↗

Analysis of single-cell cultures by immunoaffinity capillary electrophoresis with laser-induced fluorescence detection.

Neuropeptide regulation of immunological activity is becoming an important issue in both basic and clinical sciences, necessitating the need for analysis to be performed at the single-cell level. A microsampling procedure has been developed for studying secretion of biologically important peptides from neuropeptide-stimulated lymphocytes, based on microdialysis sampling coupled to immunoaffinity capillary electrophoresis (ICE), with laser-induced fluorescence (LIF) detection using a fibre-optic spectrometer and diode laser excitation. The system demonstrated a limit of detection in the high attomole (10(-18) mol/L) range with pure standards and was capable of monitoring secretion from a single cell over time. Using this system it was possible to differentiate the effects of four neuropeptides on both T and B cell release of regulatory cytokines. CD4(+) lymphocytes demonstrated a 7.5-fold increase in cytokine secretion over baseline following stimulation with substance P (SP) and calcitonin gene-related peptide (CGRP). B cells responded to CGRP and vasoactive intestinal peptide (VIP) stimulation (5.5-fold increase), but not to SP. These changes took place 12--20 h post-stimulation and, once the peak secretion had been reached, remained at that level for the duration of the experiment. This system demonstrates the ability to perform high sensitivity measurements on microsamples of biological fluids.

Electrophoresis, Capillary↗

Measurement of recombinant interferon levels by high performance immunoaffinity chromatography in body fluids of cancer patients on interferon therapy.

The technique of high performance immunoaffinity chromatography was used to measure the levels of recombinant interferon in chronic lymphocytic leukaemia patients enrolled in a phase II recombinant interferon clinical trial. The technique employed a short high pressure chromatography column packed with minute glass beads which had monoclonal antibody, directed against recombinant alpha interferon, immobilized to their surface. This system was used to measure interferon levels in a variety of different human body fluids. A good correlation was found when interferon levels, detected by chromatographic separation, were compared to levels obtained by a conventional radioimmunoassay.

Adult↗

Immunoaffinity capillary electrophoretic analysis of cyclosporin in tears.

An immunoaffinity capillary electrophoresis technique has been developed for the analysis of cyclosporin A in human tear fluid following topical application of the drug. The technique combines the selectivity of immunoaffinity separation with the high-resolution of capillary electrophoresis by immobilizing monoclonal antibody fragments directly onto the internal surface of the capillary. This technique was used to measure cyclosporin levels in tears obtained from corneal transplant patients during normal and drug toxicity episodes in the course of their treatment. Comparison of this technique with HPLC detection of cyclosporin in tears showed a good correlation, with the immunoaffinity CE technique having the advantage of being able to simultaneously detect toxic metabolites of cyclosporin in the same sample.

Adult↗

Assessing environmental exposure in children: immunotoxicology screening.

Environmental exposure to a number of xenobiotics, including pesticides, can have serious effects on the immune system of children, thus rendering them susceptible to infections or other disease states. To study this problem, a recycling chromatographic system for assessing cytokine profiles in humans has been developed and used for the measurement of immune system function in children with documented exposure to residential pesticides. The system is capable of measuring 30 different analytes in a single sample thus enabling the same time examination of representative markers of immune differentiation and function. In the present study, a cohort of 25 exposed children were examined and shown to exhibit a number of features; all subjects demonstrated some abnormalities in cytokines associated with hematopoiesis. Additionally, elevations in pro-inflammatory cytokines and neuropeptides indicated a state of generalized and neurogenic inflammation. Further analysis indicated that a depression of the cellular arm of the immune system that correlated with clinical indicators of lowered host resistance to infection could also be detected in a subgroup of the exposed subjects. All exposed children demonstrated evidence of hyperstimulation of the humoral immune system as indicated by elevated IL-5 concentrations and clinical allergy. The degree of immune dysregulation in the exposed children was found to be quite marked when compared to similar studies performed on age-matched controls.

Biomarkers↗

Antisperm antibodies in human immunodeficiency virus infection: effects on fertilization and embryonic development.

Sera from human immunodeficiency virus (HIV)-infected males (n = 10) and females (n = 5) were analyzed for the presence of antisperm antibodies reacting against sperm-specific antigens. Of the HIV-positive males tested, sera of 40% were positive for human sperm extract (HSE), 70% for protamine, and 70% for fertilization antigen (FA-1) for at least one class of antibodies, compared to sera from HIV-negative males. Of the HIV-positive females tested, sera of 40% were positive for HSE, 30% for protamine, and 30% for FA-1 compared to sera from HIV-negative females. The majority of the sperm antigen-reactive antibodies belonged to the IgG class. The reactions observed with FA-1 were weaker than those with other antigens. Ninety percent of HIV-positive male sera and 80% of the HIV-negative female sera were found to contain immune complexes, 20% of which showed the presence of FA-1. HIV-positive male or female sera did not bind to any specific protein on the Western blot of HSE. The minimal amount of free anti-FA-1 antibodies present in sera did not bind to live sperm in the sperm immobilization technique, sperm agglutination technique, or immunobead binding technique and thus were incapable of affecting human sperm penetration of zona-free hamster ova (SPA). Nor did HIV-positive sera induce any apparent abnormality in the development of 2-cell embryos to blastocysts in vitro in murine bioassay. In conclusion, these results indicate that HIV-infected patients have sperm-specific antibodies in their sera that do not adversely affect SPA and murine embryo bioassay. There was a high incidence of immune complex formation after HIV infection. These data will provide the basis for exploring further the role of sperm antigens in altering the immunoregulatory mechanisms after HIV infection.

Adult↗

Microvascular assessment of burn depth conversion during varying resuscitation conditions.

Conversion of partial- to full-thickness injuries, even after the burning has stopped, remains a significant clinical problem. We developed a rat model with a wide range of burn depths to study this phenomenon by microvascular assessment. Fifty-four male Sprague-Dawley rats weighing 460 g on average were studied. Real-time tissue monitoring of pH, paCO2, and paO2 was achieved by placement of a continuous blood gas monitor transducer in the aorta. Ten, 2-cm x 2-cm burns were created on each animal with milled aluminum templates (100 degrees C) with varying contact times. Conversion of burn depth in these wounds was documented by serial laser Doppler imager scanning over a 5-hour period. Animals received Ringer's lactate resuscitation at 0, 2, 4, 6, and 8 ml/kg/%burn. Serial laser Doppler scanning directly demonstrated progressive loss of perfusion to partial-thickness burns dependent upon the amount of fluid resuscitation. Conversion of partial- to full-thickness burns in this rat model (documented by laser Doppler microvascular assessment) was dependent upon how the animals were resuscitated.

Animals↗

The 2003 Carl A Moyer Award: real-time metabolic monitors, ischemia-reperfusion, titration endpoints, and ultraprecise burn resuscitation.

Real-time metabolic monitoring of varied vascular beds provides the raw data necessary to conduct ultraprecise burn shock resuscitation based on second-by-second assessment of regional tissue perfusion. It also illustrates shortcomings of current clinical practices. Arterial base deficit was continuously monitored during 11 clinical resuscitations of patients suffering burn shock using a Paratrend monitor. Separately, in a 30% TBSA rat burn model (N = 70), three Paratrend monitors simultaneously recorded arterial blood gas and tissue pCO2 of the burn wound and colonic mucosa during resuscitation at 0, 2, 4, 6, and 8 ml/kg/%TBSA. Paratrend data were analyzed in conjunction with previously reported laser Doppler images of actual burn wound capillary perfusion. With current clinical therapy, continuous monitoring of arterial base deficit revealed repetitive cycles of resolution/worsening/resolution during burn shock resuscitation. In the rat model, tissue pCO2 in both burn wounds and splanchnic circulation differed depending on the rate of fluid resuscitation (P <.01 between sham and 0 ml/kg/%TBSA and between 2 ml/kg/%TBSA and 4 ml/kg/%TBSA). Burn wound pCO2 values correlated well with laser Doppler determination of actual capillary perfusion (rho = -.48, P <.01). The following conclusions were reached: 1). Gratuitous and repetitive ischemia-reperfusion-ischemia cycles plague current clinical therapy as demonstrated by numerous "false starts" in the resolution of arterial base deficit; 2). in a rat model, real-time monitoring of burn wound and splanchnic pCO2 demonstrate a dose-response relationship with rate of fluid administration; and 3). burn wound and splanchnic pCO2 are highly correlated with direct measurement of burn wound capillary perfusion by laser Doppler imager. Either technique can serve as a resuscitation endpoint for real-time feedback-controlled ultraprecise resuscitation.

Acid-Base Equilibrium↗