The component glycerides of an ox depot fat.
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Biomedical subjects
Publications and source records attributed to S Paul.
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Human kappa-light chains (L chains) were amplified by the reverse transcriptase-polymerase chain reaction (PCR) and cloned into a phagemid vector. Phage particles displaying L chains were fractionated on immobilized vasoactive intestinal peptide (VIP). The resultant phage preparation displayed saturable binding of (tyr10-125I)VIP. One of the L-chain clones (hk13) was deduced to be related to subgroup I of kappa-light chains based on its nucleotide sequence. The VIP binding activity of the soluble and phage-displayed form of this L chain was confirmed by radioimmunoassay and ELISA, respectively. These observations demonstrate the potential of selecting antigen-specific L chains from phage-display libraries.
Catalytic antibodies may be produced over the natural course of antibody-affinity maturation by placement of chemically reactive residues in antibody-active sites by somatic hypermutation or V-D-J-gene rearrangement. This hypothesis has received support from recent observations on the chemical reactivity of antibodies to vasoactive intestinal peptide (VIP), DNA, and steroid- and dinitrophenyl-esters. Recent studies reveal that monoclonal antibodies raised against the ground state of VIP can accelerate the cleavage of peptide bonds. The light-chain (L-chain) subunit of human autoantibodies display increased hydrolytic rate and diminished VIP-binding affinity compared to the parent antibody, consistent with increased turnover owing to weaker binding of the substrate ground state. These observations reveal an essential limitation of catalytic antibodies, i.e., large turnover rates may be associated with diminished substrate specificity. The hydrolysis of VIP by IgG purified by affinity chromatography from asthma patients and nonasthmatic controls was compared. IgG from the majority of asthma patients displayed VIP-hydrolyzing activity. Vmax values for IgG from asthmatics tended to be higher than those from the nonasthmatic group. In principle, catalysis by antibodies may be an important mediator of immunological defense, regulation, and autoimmune dysfunction. The verification of these possibilities will require studies that utilize efficient assays of antibody catalysis during experimental immunization and autoimmune disease, as well as mechanistic investigation of catalysis by antibodies and their subunits.
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A highly purified preparation of a monoclonal antibody to vasoactive intestinal peptide (VIP) was analysed by gel filtration. Three peaks of VIP hydrolysing activity were observed, corresponding to the 150 kDa tetramer IgG, 80 kDa dimer of the heavy and light chains (H-L dimer) and 25 kDa L chain monomer. The hydrolytic activity of all three peaks was removed by adsorption on immobilized anti-mouse IgG. The specific activities (CPM hydrolysed/microgram protein) of the H-L dimer and the L chain monomer were more than 30-fold greater than of intact IgG. The presence of small amounts of the antibody fragments in unreduced IgG preparations was confirmed by electrophoresis of overloaded radiolabeled and unlabeled IgG preparations. Increased levels of the fragments were evident after prolonged incubation of a dilute solution of 125I-IgG at 37 degrees C. Iodoacetamide, a sulfhydryl alkylating reagent, suppressed the production of IgG fragments. Incubation of 125I-labeled L chain with unlabeled IgG resulted in incorporation of small amounts of the radioactivity into disulfide bonded 150 kDa IgG tetramer and 50 kDa L chain dimer fractions. These observations implicate disulfide reduction and exchange reactions as the mechanism underlying formation of the IgG fragments. Like the antibody fragments found in unreduced IgG, the L chain monomer and non-covalently associated H-L dimer isolated from reduced and alkylated IgG were capable of hydrolysing VIP. Hydrolysis of VIP by the recombinant L chain subunit was inhibited by excess IgG, suggesting that high affinity VIP binding by IgG limits its hydrolysis by the L chain. These observations suggest that small amounts of high activity antibody fragments may contribute to the catalytic characteristics of the anti-VIP IgG preparation.
VIP was labeled with sodium 125iodide, and 125I-VIP was purified by reverse-phase high performance liquid chromatography. Optimal separations of 125I-VIP and unlabeled VIP were obtained using two C18-Novapak columns in series and a gradient of acetonitrile in triethylamine phosphate for elution. The specific activity of the 125I-VIP was 1.99 +/- 0.21 Ci/mumole, approaching the maximum specific activity of monoiodinated VIP (2.26 Ci/mumole). Radioimmunoassay and radioreceptorassay for VIP were more sensitive (2.6-fold, and 2.5-fold, respectively) using 125I-VIP purified by HPLC compared to 125I-VIP obtained from an open-end cellulose column. These results demonstrate the advantage of preparing purified 125I-VIP by HPLC for the accurate assay of VIP and VIP-receptors in tissues and biological fluids.
Despite advances in the prevention and treatment of many cardiovascular diseases, congestive heart failure (CHF) remains a major cause of morbidity and death in most developed countries. During this era of uncertainty in health care, cost-conscious tactics are being implemented widely among U.S. hospitals. One such tactic, in the form of a multidisciplinary outpatient CHF clinic, was implemented in June of 1995 at a university medical center in the southeastern United States. This article discusses the process of developing a collaborative multidisciplinary outpatient CHF clinic, and the concomitant clinical development of the nurse practitioner role.
The concept of cancer immunotherapy and the resulting technical advances have evolved considerably during the last decade. However, cancer treatment by recombinant IL-2 or IFN-alpha still represents today the best therapeutic way for the treatment of renal carcinoma, melanoma and in some cases lymphoma. The immunotherapy approaches such as vaccination, gene and cellular therapy, have not yet demonstrated a sufficient clinical efficacy for the treatment of solid tumors. The goal of this review is to summarize the different approaches to cancer immunotherapy developed today. Specific approaches such as antigenic vaccination will be first described, then non-specific approaches such as gene transfer on the tumor site of immuno-stimulating genes will be discussed.
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The catalytic monoclonal antibody 9A8 (MA 9A8), antiidiotypic to the antibody AE-2 (MA AE2) produced to the active site of acetyl cholinesterase from human erythrocytes, was subjected to a structure-function study. The specific binding of MA 9A8 to MA AE2 (K 2.26 x 10(9) M-1) was shown by the method of surface plasmon resonance, and the functional activity of MA 9A8 was demonstrated. Unlike acetyl cholinesterase, this antibody specifically reacted with the irreversible phosphonate inhibitors of esterases. A peptide map of MA 9A8 was analyzed by MALDI mass spectrometry. The Ser99 residue of its heavy chain was shown to be within the active site of the catalytic antibody. A computer modeling of the MA 9A8 active site suggested the existence of a catalytic dyad formed by Ser99 and His35. A comparison of the tertiary structures of the MA 9A8 and the 17E8 monoclonal antibody, which also exhibited an esterase activity and was produced to the stable analogue of the reaction transition state, indicated a practically complete coincidence of the structures of their presumed active sites.
OBJECTIVE: The objectives of this study are to (1) Address issues related to selecting a quality of life (QOL) measuring tool; and (2) Present data from a pilot test comparing 3 QOL tools (Medical Outcomes Study Short Form-36 [SF-36], the Minnesota Living with Heart Failure Questionnaire [LHFQ], and a visual analogue scale). DESIGN: Descriptive comparative. SETTING: A Southern university-affiliated tertiary medical center outpatient heart failure clinic. PATIENTS: Thirty adults, randomly selected from those treated in a multidisciplinary, nurse practitioner-managed heart failure clinic. RESULTS: Significant correlations were found among the global or broader measures of QOL (visual analog scale and LHFQ Total score) and the component scores (LHFQ Emotional, LHFQ Physical, SF-36 Mental [MCS], and SF-36 Physical [PCS]), with the only exception being that of the LHFQ Total and the SF-36 PCS. Mental and physical components of QOL were not related within the SF-36 or between the SF-36 PCS and the LHFQ Emotional score. However, the emotional and physical scores were highly and significantly related within the LHFQ and between the SF-36 MCS and the LHFQ Physical score. CONCLUSIONS: The SF-36 was better able to differentiate physical and emotional aspects of QOL in this sample. The LHFQ subscales may be less useful in QOL assessment than the total score.
BACKGROUND: Although clinicians often rely on patients' retrospective reporting of dyspnea, it is not known if dyspnea scores recalled after exercise are equivalent to dyspnea scores during exercise. The objective of this study was to determine whether patients could accurately recall after exercise the maximum ratings of the intensity of dyspnea and the anxiety associated with it that they experienced during exercise. METHODS: Forty-nine patients with chronic obstructive pulmonary disease (COPD) (forced expiratory volume in 1 second 0.92 +/- 0.23 L) participating in a randomized clinical trial of the impact of coached versus monitored exercise training on dyspnea rated dyspnea intensity (shortness of breath [SOB]) and dyspnea-related anxiety (DA) on a visual analog scale every 2 minutes during treadmill exercise. After each of 12 training sessions each subject was asked to rate the worst level of the two sensations that they recalled having experienced during exercise. RESULTS: For the groups as a whole, actual maximum scores for SOB and DA during exercise were highly correlated with recalled maximum values after exercise (r > or = 0.85, P < 0.0001) and the average differences were small (0-10.9 mm on a 200-mm scale). However, individual variation was substantial, limiting predictability for individual ratings. CONCLUSIONS: After exercise, patients with COPD as a group can accurately recall the worst SOB and DA that they experienced during exercise. This finding supports the further study and use of retrospective symptom ratings as a method for dyspnea assessment during exercise training in pulmonary rehabilitation.
We generated 149 hybridoma cell lines secreting antibodies against human spermatozoal antigens of which antibodies from 136 hybridoma lines also reacted with seminal plasma constituents. The occurrence of common antigeneic determinants on spermatozoa and seminal plasma was further demonstrated by competitive inhibition ELISA tests. We found that seven hybridoma clones secreted antibodies reactive with spermatozoa but nonreactive with seminal plasma. Antibodies from 5 clones were sperm-agglutinating and from 15 clones sperm-immobilizing. Localization of sperm antigens reactive with the monoclonal antibodies was demonstrated by indirect immunoperoxidase staining. A synthetic decapeptide, earlier shown to be reactive with naturally occurring human iso- and autosperm antibodies, was shown to be reactive with the monoclonal antibody VII-5 in ELISA tests.
OBJECTIVE: To assess the efficacy of a short course chemotherapy regimen for treating tuberculosis of the lymph nodes in children. DESIGN: Open, collaborative, outpatient clinical trial. SETTING: Outpatient department of the Tuberculosis Research Centre, paediatric surgery departments of the Institute of Child Health and Hospital for Children and the Government Stanley Hospital, Madras, South India. PATIENTS: Children aged 1-12 years with extensive, multiple site, superficial tuberculous lymphadenitis confirmed by biopsy (histopathology or culture). INTERVENTIONS: Patients were treated with a fully supervised intermittent chemotherapy regimen consisting of streptomycin, rifampicin, isoniazid, and pyrazinamide three times a week for two months followed by streptomycin and isoniazid twice a week for four months on an outpatient basis. Surgery was limited to biopsy of nodes for diagnosis and assessment. MAIN OUTCOME MEASURES: Response to chemotherapy was assessed by regression of lymph nodes and healing of sinuses and abscesses during treatment and follow up. Compliance with treatment and frequency of adverse reactions were also estimated. RESULTS: 197 Patients were admitted to the study and 168 into the analysis. The regimen was well tolerated and compliance was good with 101 (60%) patients receiving the prescribed chemotherapy within 15 days of the stipulated period of six months. Those whose chemotherapy extended beyond that period received the same total number of doses. Clinical response was favourable in most patients at the end of treatment. Sinuses and abscesses healed rapidly. Residual lymphadenopathy (exceeding 10 mm diameter) was present in 50 (30%) patients at the end of treatment; these nodes were biopsied. Fresh nodes, increase in size of nodes, and sinuses and abscesses occurred both during treatment and follow up. After 36 months of follow up after treatment only 5 (3%) patients required retreatment for tuberculosis. CONCLUSION: Tuberculous lymphadenitis in children can be successfully treated with a short course chemotherapy regimen of six months.
Neural networks were developed to predict perioperative cardiac complications with data from 567 vascular surgery patients. Neural network scores were based on cardiac risk factors and dipyridamole thallium results. These scores were converted into likelihood ratios that predicted cardiac risk. The prognostic accuracy of the neural networks was similar to that of logistic regression models (ROC areas 76.0% vs 75.8%), but their calibration was better. Logistic regression overestimated event rates in a group of high-risk patients (predicted event rate, 64%; observed rate 30%; n=50, p<0.001). On a validation set of 514 patients, the neural networks still had ROC similar areas to those of logistic regression (68.3% vs 67.5%), but logistic regression again overestimated event rates for a group of high-risk patients. The calibration difference was reflected in the Hosmer-Lemeshow chi-square statistic (18.6 for the neural networks, 45.0 for logistic regression). The neural networks successfully estimated perioperative cardiac risk with better calibration than comparable logistic regression models.
The porcine RN locus affects muscle glycogen content and meat quality. We previously mapped the RN locus to chromosome 15. This study describes the identification of polymorphisms for four class I and four class II markers located in the RN region. Resource families were genotyped with F-SSCP markers (fluorescent single strand conformation polymorphism) and microsatellite markers. Subsequent multipoint linkage analysis revealed the order FN1-IGFBP5-S1000-S1001-IL8RB-VIL1-RN-Sw936-Sw906. The gene order is identical to the previously reported porcine RH map of the same region. The described map will facilitate positional cloning of the RN gene.