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J J Thompson

Publications and source records attributed to J J Thompson.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of "modified-self"-induced specific antibody hyporesponsiveness to herpes simplex virus.

Pretreatment of mice iv with syngeneic spleen cells modified with soluble HSV envelope antigens induced an anti-HSV antibody hyporesponsiveness following challenge with infectious virus. The epitope density on the HSV-modified spleen cells was quantitated using a photon-counting spectrofluorimeter so that observed immunological results could be correlated with the HSV antigen dose on the splenocytes. The degree of anti-HSV antibody hyporesponsiveness was found to be related to the epitope density on the HSV-modified spleen cells, but not the number of modified cells used in the pretreatment over the 16-fold range tested. Anti-HSV antibody hyporesponsiveness was induced if 7, but not 3, days had elapsed between pretreatment and challenge. This antibody hyporesponsiveness could be adoptively transferred with T cells. Only mice that had induced an anti-HSV antibody hyporesponsiveness following pretreatment with HSV-modified splenocytes were able to survive an LD50 challenge with infectious virus.

Animals↗
PubMed1992

Optimization and characterization of capture ELISA methodology for Lp(a) lipoprotein quantification.

In order to better characterize and optimize a typical capture ELISA system for Lp(a) lipoprotein, we have analysed kinetic details of the reaction. Plate coating with polyclonal antibody, recognition of captured analyte with monoclonal antibody, and detection of monoclonal antibody with alkaline phosphatase-labeled antiglobulin were essentially complete after one hour, probably being driven forward by a relative excess of reagent. However, complete capture of the Lp(a) analyte required about 6 h at low input concentrations. Shorter time periods for capture might therefore result in decreased sensitivity and reproducibility. Deviations from linearity in the assay dose response were associated with incomplete capture of Lp(a) and significant depletion of the monoclonal recognition antibody. With the final reaction conditions described, no significant differences in immunochemical reactivity between samples were found by analysis of dose response slopes. Finally, interferences from plasminogen, -20 degrees C storage, anticoagulants, LDL, haemolysis, and bilirubin were minimal.

Animals↗
PubMed1991

Divergent efficacy of antibody to tumor necrosis factor-alpha in intravascular and peritonitis models of sepsis.

The role of tumor necrosis factor-alpha (TNF alpha) in the lethal consequences of intravascular lipopolysaccharide (LPS) or Escherichia coli sepsis was compared with that in bacterial peritonitis. Intravenous administration of E. coli LPS or E. coli (live or dead) resulted in large transient increases in serum TNF alpha levels, peaking at 90 min at 10,000-30,000 units/ml. In contrast, the serum TNF alpha response following the induction of bacterial peritonitis was substantially less, peaking at 200-500 units/ml. Sterile peritonitis (essentially nonlethal) and bacterial peritonitis (greater than 60% lethal) elevated TNF alpha levels to 1000-2000 units/lavage within the peritoneal cavity 2 h after challenge. Passive immunization with neutralizing goat anti-TNF alpha IgG improved survival from 8% to 75% in rats administered LPS intravenously but was completely ineffective in protecting rats from lethal E. coli peritonitis. Thus significant differences exist in the role TNF alpha plays in systemic intravascular models of sepsis and bacterial peritonitis.

Animals↗
PubMed1989

Efficient electroblotting of human very-low-density lipoproteins and low-density lipoproteins from composite gradient gels to nylon membranes.

Rinsing of gradient composite acrylamide/agarose gels with 1% Triton X-100 permits the efficient electrotransfer of very-low-density and low-density lipoproteins from the gels and does not appear to interfere with subsequent capture of the lipoproteins by charged nylon membranes. Overall efficiency of the transfer/capture process can approach 95% and does not appear to be significantly affected by total lipoprotein concentrations up to 5000 mg/dl. Direct immunoquantification of transferred apolipoproteins on the membrane is feasible as well. The nylon membranes used, however, must be pretested to ensure capture efficiency.

Detergents↗
PubMed1989

Talc deposition and effects after 20 days of repeated inhalation exposure of rats and mice to talc.

The relationship between the inhalation exposure concentration of talc and the resulting lung burdens and histologic lesions was studied using groups of 20 F344/Crl rats and 20 B6C3F mice (10 male and 10 female) exposed to one of three concentrations of asbestos-free talc for 6 hr/day, 5 days/week for 4 weeks. Controls were exposed to filtered air using the same schedule. The pulmonary retention of talc and the development of pulmonary pathology were evaluated. The mass median aerodynamic diameter (MMAD) of the talc aerosol was 3.0 microns with a geometric standard deviation (sigma g) of 1.9. The mean exposure concentrations for rats were 0, 2.3, 4.3, and 17 mg talc/m3. Lung burdens in rats averaged 0, 0.07, 0.17, and 0.72 mg talc/g lung after the 20-day inhalation exposure; thus, the amount retained in the lung per unit of exposure concentration increased with increasing concentration. Mean exposure concentrations for the mice were 0, 2.2, 5.7, and 20.4 mg of talc/m3, which resulted in lung burdens of 0, 0.10, 0.29, and 1.0 mg talc/g lung; thus, the relationship between exposure concentration and the amount retained in the lung was approximately constant. Lung burdens from this study were used to project lung burdens that would result from longer exposures of rodents and man. No clinical signs were observed in the rats or mice prior to sacrifice 24 hr after the last exposure day. Histologic alterations in lung tissue consisted of only a modest, diffuse increase of talc-containing, free macrophages within alveolar spaces in both rat and mouse groups exposed to the highest level of talc for 20 days. A model simulating chronic talc inhalation exposure of rats and mice predicted lung burdens of 2-3 mg talc/g lung (wet wt) if animals were exposed to 17 mg talc/m3 for 2 years, and deposition and clearance of talc were unchanged by continued exposure. A potential limitation in this modeling is that if clearance of talc is delayed by continued exposure, the accumulated talc lung burdens would be higher than those projected by the simulation model. Humans exposed to aerosols of respirable talc are projected to accumulate much higher lung burdens than would occur in rodents exposed to the same aerosol, because humans have a higher estimated deposition fraction and slower estimated clearance of the deposited talc dust. Equilibrium lung burdens of greater than or equal to 2 mg talc/g lung were predicted for human exposures at or near the TLV for talc.

Aerosols↗
PubMed1989

Compartmentalization of intraalveolar and systemic lipopolysaccharide-induced tumor necrosis factor and the pulmonary inflammatory response.

Tumor necrosis factor-alpha (TNF), a monokine produced by lipopolysaccharide (LPS)-stimulated macrophages, is an activator of phagocytic functions and may modulate host responses during infection. To determine the effects of LPS on TNF activity and the pulmonary inflammatory response in vivo, we challenged rats systemically or intratracheally with LPS. Intravenous LPS significantly increased serum TNF content from nondetectable levels in control specimens to peak levels at 90 min, which declined to baseline by 3 h. In response to intratracheal LPS, levels of TNF both in bronchoalveolar lavage fluid and associated with alveolar macrophages increased significantly from near nondetectable levels in control animals. Increases in TNF levels were confined to the LPS-challenged compartment. Intravenous LPS resulted in a decrease in the number of peripheral blood neutrophils and in sequestration of these cells within the pulmonary vasculature. In contrast, intratracheal LPS elicited a marked intraalveolar inflammatory response.

Animals↗
PubMed1989

Effect of low zinc intake on absorption and excretion of zinc by infants studied with 70Zn as extrinsic tag.

The effect of low dietary intake of zinc was studied in six normal infants with the use of 70Zn as an extrinsic tag. Of the two study formulas, one provided a zinc intake similar to that of customary infant formulas ("high" intake), whereas the other provided a "low" zinc intake. Two zinc absorption studies were performed with each formula (sequence: high-low-low-high). Extrinsically labeled formula was fed for 24 h and excreta were collected for 72 h. Zinc isotope ratios were determined by inductively coupled plasma mass spectrometry (ICP/MS). When zinc intake was high, net zinc absorption was 9.1 +/- 8.7% (mean +/- SD) of intake and net zinc retention was 74 +/- 91 micrograms/(kg.d). True zinc (70Zn) absorption was 16.8 +/- 5.8% of intake and fecal excretion of endogenous zinc was 78 +/- 56 micrograms/(kg.d). When zinc intake was low, net absorption of zinc increased significantly (P less than 0.001) to 26.0 +/- 13.0% of intake, but net retention was not significantly different at 42 +/- 33 micrograms/(kg.d). True absorption of zinc also increased significantly (P less than 0.001) to 41.1 +/- 7.8% of intake, whereas fecal endogenous zinc decreased (P less than 0.05) to 34 +/- 16 micrograms/(kg.d) during low zinc intake. Thus, infants maintain zinc balance in the face of low zinc intake through increased efficiency of absorption and decreased excretion of endogenous zinc.

Adaptation, Physiological↗
PubMed1989

Intrahepatic assembly of very low density lipoproteins: immunologic characterization of apolipoprotein B in lipoproteins and hepatic membrane fractions and its intracellular distribution.

Monoclonal antibodies, prepared against rat apoB, were used to examine apoB structure in serum lipoproteins and characterize the forms and localization of apoB in liver membrane fractions and cultured hepatocytes. Of the several antibodies obtained, four, having separate epitopes, were characterized. Western blot analysis showed that three (DB11, F4, and LB14) antibodies recognized both apoBL and apoBS. One antibody (HB41) recognized only apoBL. This antibody showed unusual properties. Competition ELISA assays showed that the epitope recognized by HB41 was more effectively expressed on low density lipoproteins (LDL) compared to very low density lipoproteins (VLDL). In addition, treatment of lipoproteins with detergents and sulfhydryl reducing agents also increased the expression of the HB41 epitope. Since HB41 has been found to inhibit LDL binding to hepatocyte receptors, these data indicate that the HB41 epitope is located on the carboxy-terminal side of the apoBS junction (probably within the LDL receptor binding domain). Western blotting hepatic microsomal subfractions showed that in the rough and smooth microsomes, HB41 recognized only apoBL, while in the Golgi it recognized both apoBL and a protein having a molecular weight slightly smaller. In contrast, Western blotting with a polyclonal antibody known to recognize both apoBL and apoBS showed that, in rough and smooth microsomes, proteins in addition to apoBL and apoBS having molecular weights between 120,000 and 30,000 were recognized. These proteins, likely to be proteolytic fragments of apoB, were barely detectable in the Golgi. Additional biosynthetic studies show that the [35S]methionine-labeled proteins smaller than apoB were immunoprecipitated from the rough microsome subfraction. Pulse-chase experiments show that these are produced with the same kinetics as full-size apoBL and apoBS, indicating that they are not incomplete nascent chains. Finally, immunofluorescence microscopy was used to determine the localization of monoclonal epitopes. ApoB monoclonal antibodies that recognized exclusively apoBL (HB41) and apoBL and apoBS (DB11) produced an immunofluorescence pattern characteristic of the endoplasmic reticulum, but not the Golgi. These data suggest that, in cultured rat hepatocytes, the majority of both molecular weight forms of apoB are localized in the endoplasmic reticulum, the initial site of VLDL assembly. The additional finding that proteolytic fragments of apoB are enriched in the microsomal fraction suggests that if the proteolysis occurs during subcellular fractionation, immature apoB is susceptible to proteolysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Temporal response of lipoprotein lipase-suppressing mediator and tumor necrosis factor in lipopolysaccharide -injected and -infused rats.

This study was initiated to compare the temporal response of serum lipoprotein lipase-suppressing mediator (LSM) and tumor necrosis factor (TNF) in lipopolysaccharide (LPS) -infused or -injected rats. Serial blood samples were obtained over a 5-day period from rats implanted with vascular catheters. Control rats infused with saline exhibited no detectable LSM activity during the 5-day observation period. LPS administered either by injection or infusion (6 h or 5 d) resulted in detection of serum LSM and TNF activities during the early period of observation with the LSM temporal response (8 h) outlasting the TNF response (3 h). The LSM response lasted a little longer in LPS-infused rats than it did in injected rats, but in each case LSM activity was not detected in serum samples collected at or after 12 h post-LPS. Neither the duration nor the magnitude of the TNF response differed between LPS-infused vs. -injected rats. Despite similarities in the LSM and TNF pattern in all rats receiving LPS, lethality was greater in LPS-infused animals than it was in LPS-injected rats. The results indicate that differences in lethality between LPS-injected and -infused rats cannot be explained solely by a differential response of serum TNF.

Animals↗
PubMed1988

Glucose kinetics in rats infused with endotoxin-induced monokines or tumor necrosis factor.

This study was conducted to determine if macrophage elaborated monokines in general, and human recombinant tumor necrosis factor (hrTNF alpha) in particular alter glucose metabolism in a manner analogous to that observed in endotoxin-treated animals. Endotoxin-tolerant rats were infused for 3 hr with saline, E. coli endotoxin (100 micrograms/l weight) or monokines contained in conditioned media from endotoxin-stimulated RAW 264.7 cells (1 microgram/ml). Compared to saline- and endotoxin-infused rats, animals receiving the monokine mixture had no change in mean arterial blood pressure or heart rate but exhibited overt signs of morbidity including stupor and diarrhea. Monokine-infused rats remained euglycemic but had elevated lactate concentrations and a 15-30% increase in glucose rate of appearance (Ra). Nontolerant rats received a 3 hr infusion of saline, hrTNF alpha (15 micrograms/100 g), or heat-treated hrTNF alpha. HrTNF alpha infusion increased glucose Ra about 25% compared to the two control groups but did so without producing signs of morbidity seen in the monokine infused animals. Serum TNF levels were 6-fold higher in rats infused with the monokine mixture compared to animals infused with hrTNF alpha, and this reflected the different levels of TNF contained in the monokine mixture and hrTNF alpha infusates. Plasma insulin, glucagon, and catecholamine concentrations were increased in rats infused with either the monokine mixture or hrTNF alpha, but the increases were more pronounced in rats receiving the monokine mixture. The results demonstrate that monokines and hrTNF alpha increase glucose production in vivo, and that the effect may be mediated by endocrine changes known to influence glucose homeostasis.

Animals↗
PubMed1987

Gradient acrylamide/agarose gels for electrophoretic separation of intact human very low density lipoproteins, intermediate density lipoproteins, lipoprotein a, and low density lipoproteins.

An exponential gradient gel with 0-10% acrylamide and 0.5% agarose was developed for electrophoresis of intact high molecular weight lipoproteins. This system resolves very low density lipoproteins, intermediate density lipoproteins, lipoprotein a, and low density lipoproteins in a size-dependent fashion. The characteristic relative mobility of these species can be determined in relation to protein and colloidal gold reference materials. Electron microscopy of selected lipoprotein fractions confirmed that relative mobility was related to apparent lipoprotein diameter. The composite gel medium can be used with prestained lipoproteins and permits immunoelectroblotting for qualitative analysis of apolipoprotein constituents.

Electrochemistry↗
PubMed1986

Lipoprotein lipase-suppressing mediator in serum of endotoxin-treated rats.

The conditions under which lipoprotein lipase-suppressing mediator is present in serum of endotoxin-treated rats was determined in this study. The suppression of lipoprotein lipase activity in 3T3-L1 cells was used as a bioassay for mediator in serum. Endotoxin (0.1-10 micrograms/ml) and serum from control rats did not suppress lipoprotein lipase activity. Maximum suppression of cell lipoprotein lipase activity (70%) by serum from endotoxic rats required a cell exposure time of 5 h. At the highest dose of endotoxin used (1 mg/100 g), significant suppression was achieved when cells were incubated with 0.5% serum from endotoxic rats (P less than 0.05). Serum obtained 2-3 h after endotoxin injection possessed the maximal ability to suppress lipase activity, but suppressing activity was not present in serum collected 8 h after endotoxin. Rats rendered tolerant to endotoxin by 5 daily injections (0.1 mg/100 g) did not contain detectable levels of mediator in serum after endotoxin injection. The results demonstrate that the presence of lipoprotein lipase activity-suppressing mediator is transitory after in vivo exposure of naive rats to endotoxin, but does not appear in serum of endotoxin tolerant rats.

Animals↗
PubMed1986

Juvenile periodontitis. I. Demonstration of local immunoglobulin synthesis.

The purpose of this investigation was to determine the presence and quantity of immunoglobulin G (IgG) and albumin (ALB) in specified periodontal tissues and serum from patients diagnosed as having juvenile periodontitis (JP), using an immunoelectrophoresis technique and to determine which portion of the lesion generated the greatest local immunoglobulin production. Serum and tissue samples were obtained from 19 patients (ages 13-21 years) who were diagnosed as having JP; 18 were female; 16 were black. Normal, diseased, and granulomatous gingival/periodontal tissues were collected during full thickness flap surgery, then minced, homogenized, and centrifuged. Supernatants containing the gingival/periodontal protein and the serum were electrophoresed against rabbit antihuman IgG and ALB. The relative IgG/ALB ratios in each specimen were plotted against known concentrations of IgG using a least squares analysis to provide evidence for local synthesis. In comparing mean IgG/ALB ratios for all tissue types, it was noted that normal gingiva did not differ significantly from serum. Diseased and granulomatous tissues, taken together or separately, had significantly higher IgG/ALB ratios than normal gingiva or serum, demonstrating that 73.6% of the IgG present was due to local synthesis. However, the greatest amounts of locally produced IgG were found in the granulomatous tissue from the deepest areas of the defects.

Adolescent↗
PubMed1985

Production and characterization of a monoclonal antibody to dog hepatic lipase.

Partially purified dog hepatic lipase was used as antigen to produce monoclonal antibodies in mice. In addition to enzyme-linked immunosorbent assay (ELISA), a reliable and efficient procedure for screening antibodies reacting to hepatic lipase has been developed. A method to distinguish antibodies directing to active site or non-active site epitopes has also been described. We obtained three positive clones that survived after subcloning and expansion. All three monoclonal antibodies possess gamma one (gamma 1) heavy chains and kappa (kappa) light chains. Specificity of monoclonal antibody LDHL No. 537 to dog hepatic lipase was demonstrated by passing post-heparin plasma through its immunoaffinity column. Only dog hepatic lipase was removed by LDHL No. 537 from post-heparin plasma. The immunoaffinity chromatography also demonstrated the co-existence of three enzyme activities (mono- and triacylglycerol lipase and phospholipase A1) on the dog hepatic lipase molecule. The subunit weight of dog hepatic lipase has been estimated at 57500 +/- 600 (n=3) by using immunoaffinity chromatography and the combination of immunoprecipitation and autoradiography methods.

Animals↗
PubMed1985

Identification of a mouse monoclonal antibody, LHLP-1, specific for human Lp(a).

Heretofore, immunologic reagents used to define and quantify human Lp(a) have been polyclonal in origin and therefore heterogeneous in antigenic specificity. We report here the isolation of a mouse monoclonal antibody, LHLP-1, monospecific for Lp(a). The antigen reactive with LHLP-1 was expressed in both lipoprotein Lp(a) as well as apolipoprotein Lp(a) delipidated by SDS treatment; however, disulfide reduction of apolipoprotein Lp(a) inhibited LHLP-1 reactivity. The antigen reactive with LHLP-1 on Lp(a), therefore, appears not to require lipid for expression of its conformationally dependent (disulfide-inhibitable) epitope. Antigen reactivity was virtually absent in the apoB and other proteins contained in very low density, low density, and high density lipoprotein particles. Immunologic quantification of Lp(a) in individual serum samples with a rabbit reference antiserum or LHLP-1 showed good correlation. We conclude that the monoclonal antibody LHLP-1 identifies an antigen unique to Lp(a) and that this antibody may therefore be useful in the further characterization and measurement of human Lp(a).

Animals↗
PubMed1984

Adenocarcinoma of the esophagus: relationship to Barrett mucosa.

Primary adenocarcinoma of the esophagus is thought to be a rare lesion. However, pathologic records at our institution from 1979 to 1982 show that adenocarcinoma accounted for 17 of 89 (19%) of all primary malignant tumors in the esophagus. All 17 cases arose in Barrett mucosa. In eight cases, there was surgically proved involvement of the gastric cardia or fundus. In six of these cases, there was evidence of esophageal dysplasia and/or carcinoma in situ adjacent to or remote from the proximal margin of the tumor. The pathologic findings therefore strongly suggest an esophageal origin of these lesions with subsequent spread into the stomach. Clinical and radiographic findings at presentation were indistinguishable from those of squamous cell carcinoma. However, 10 patients had long-standing reflux symptoms, and Barrett esophagus had presumably been present for some time prior to the development of malignancy. Since adenocarcinoma evolves through a sequence of dysplasia and carcinoma in situ in pre-existing Barrett epithelium, the best hope for improving survival may be periodic endoscopic surveillance of asymptomatic individuals who have this condition.

Adenocarcinoma↗