Search PubMed⌕ Search

Biomedical subjects

D H Beezhold

Publications and source records attributed to D H Beezhold.

At least 37 records · Page 2Linked to original sources
PubMed1996

Serum phospholipase A2 activity in patients with rheumatoid arthritis before and after treatment with methotrexate, auranofin, or combination of the two.

OBJECTIVE: (1) To confirm a previous observation that serum phospholipase A2 (PLA2) activity correlates with disease activity in rheumatoid arthritis (RA); and (2) to determine whether serum PLA2 activity changes after treatment with methotrexate (MTX), auranofin (AF), or a combination of the 2 (COMBO). METHODS: Sera obtained at baseline and after treatment from 100 patients with RA (40 MTX, 32 AF, and 28 COMBO) who participated in a multicenter, double blind trial were tested for PLA2 activity using an assay that measures the release of radiolabeled 14C oleic acid from the cell membrane of Escherichia coli. Detailed statistical analysis was performed using previously collected clinical data to determine whether correlations exist between RA disease activity and serum PLA2 activity; whether baseline serum PLA2 activity predicted a therapeutic response in any treatment group; and whether there was a significant change in serum PLA2 activity after treatment in patients who responded to the various drugs. RESULTS: Baseline serum PLA2 activity was significantly increased in patients with RA compared to healthy controls. No correlation between serum PLA2 activity and RA disease activity was noted at baseline. Mean serum PLA2 activity did not change significantly after treatment with MTX, AF, or COMBO in either treatment responders or nonresponders. CONCLUSION: Serum PLA2 activity is increased in patients with RA compared to healthy controls, but does not correlate with disease activity in patients, nor does it predict a response to treatment with MTX, AF, or COMBO. Serum PLA2 activity also did not change significantly after treatment with any of the above agents.

Adult↗
PubMed1995

Allergy to latex rubber.

OBJECTIVE: To summarize the clinical symptoms of latex rubber allergy and provide guidelines for the management of this allergy. DATA SOURCES: The English-language literature was searched from 1979 through 1994 manually and using MEDLINE. Conference proceedings and reference lists of relevant articles were reviewed. DATA EXTRACTION: Studies clinically relevant to latex allergy were selected. RESULTS: The most common clinical presentation of latex allergy is a nonimmunologic, irritant dermatitis of the hand. Contact dermatitis (type IV delayed hypersensitivity reactions to rubber additives) is the most common immunologic manifestation of latex rubber allergy. Type I allergic responses are less common and include contact urticaria, rhinoconjunctivitis, asthma, and anaphylaxis. Seven percent to 10% of health care workers regularly exposed to latex and 28% to 67% of children with spina bifida have a positive skin test result to latex proteins indicating increased blood levels of IgE antibody. About one third of patients with positive skin test results, however, do not yet have symptoms of latex allergy. Systemic (life-threatening) anaphylactic shock can occur intraoperatively in highly sensitive patients because of mucosal absorption of latex protein allergens from the surgeon's gloves. The present treatment for latex allergy is careful avoidance of latex materials. In addition, the use of powder-free latex gloves can eliminate airborne latex exposure and can allow health care workers with inhalant allergic reactions to return to work. CONCLUSION: Latex allergy currently affects thousands of people. These persons have IgE-mediated cutaneous, respiratory, and systemic allergic reactions. A reduction of the total protein level on latex rubber devices may prevent further sensitization and eliminate latex allergic reactions.

Algorithms↗
PubMed1995

Mycoplasma hyorhinis molecules that induce tumor necrosis factor alpha secretion by human monocytes.

Mycoplasma hyorhinis has been shown to induce the secretion of tumor necrosis factor alpha (TNF-alpha) from monocytes. To identify the molecules responsible for this activity, we separated sonicated M. hyorhinis lysate material by centrifugation at 100,000 x g into soluble (S) and particulate (P) fractions. The fractions were assayed for TNF-alpha-inducing activity by the L929 bioassay. Both the soluble and particulate fractions were able to induce TNF-alpha in roughly equal amounts. The optimum dose for both fractions was 1 micrograms/ml. Proteinase K treatment of either fraction eliminated the activity, suggesting that a protein component is involved in induction. Phase partitioning into Triton X-114 aqueous (A) and detergent (D) phases showed that the soluble fraction was composed of 80% aqueous-phase proteins, while the particulate fraction was > 75% detergent-phase proteins. All four fractions (SA, SD, PA, and PD) were able to induce TNF-alpha release. Treatment with NaIO4 to remove carbohydrate reduced the inducing activity of the SA phase by 80%, whereas that of the other fractions was unaffected by this treatment. The M(r)S of the inducing activity were determined by the monocyte Western (immunoblot) technique. The SA phase activity was associated with a single periodate-sensitive peak of 69 to 75 kDa. The two detergent phases had similar profiles of inducing activity, containing four peaks of activity. These peaks corresponded to 48 to 52, 43 to 45, 39 to 40, and 31 to 32 kDa. The PA fraction also contained four peaks of activity, 69 to 75, 55 to 57, 48 to 52, and 39 to 40 kDa. Thus, both a protein and glycan moiety from M. hyorhinis are capable of inducing TNF-alpha release from human monocytes.

Bacterial Proteins↗
PubMed1995

IgE-dependent reactions to urologic catheter extracts by skin testing in latex-allergic patients.

BACKGROUND: Latex allergy is mediated by residual IgE-binding proteins found on latex products. While most reported reactions involve latex gloves, the allergenic potential of other latex containing devices is unknown. OBJECTIVE: To assess the allergenic potential of latex urologic catheters. METHODS: Two identical lots of urologic catheters were extracted in sterile saline and analyzed for latex protein content using sensitive ELISA and Western blot assays. The extracts were tested by skin prick testing in a population of 47 latex-allergic patients. RESULTS: Latex proteins were detected by ELISA assay, however, the Western Blot method was not sensitive enough to measure latex proteins in these catheter extracts. Skin prick testing using a standard latex reagent (Bencard) demonstrated the test population to be extremely sensitive to latex as 68% of the population reacted to a 1/100,000 dilution. Using undiluted catheter extracts, only 11% of these latex-allergic patients reacted to catheter lot A and 2% to catheter lot C, by prick skin test. Eight percent of the control patients had a positive latex prick skin test and none reacted to the catheter extract. CONCLUSIONS: The data suggest that processing and leaching of these specific latex urologic catheters resulted in a very low latex allergen content. The low prevalence of skin test reactivity in a population of latex-allergic patients suggests that these catheters would be an unusual cause of allergic reactions. It is not possible, however, to determine whether latex-allergic patients could safely use latex urologic catheters.

Adolescent↗
PubMed1994

Identification of a 46-kD latex protein allergen in health care workers.

Latex allergy is an occupational hazard for health care workers. Extractable latex proteins are known to be allergenic, but most latex allergens have not been specifically identified. The purpose of this study was to characterize the IgE response of latex-allergic patients to latex proteins and to identify common protein allergens. Serum was obtained from 40 individuals who were skin test-positive to latex; 85% were health care workers. Western blots for IgE reactivity were performed using both ammoniated (AL) and non-ammoniated (NAL) latex proteins and IgE-reactive NAL proteins were analysed by microsequence analysis. The patients were grouped according to common patterns of reactivity. Pattern 1, the most common pattern of reactivity (9/40 patients) recognized two protein bands in both NAL and AL at 46 and 110 kD. A second, heterogeneous pattern of reactivity (pattern 2) recognized a diffuse pattern of polypeptides in the AL preparation. The n-terminal amino acid sequences for allergens at 14, 18, 29, 46 and 110 kD were determined. Sequence analysis identified the 14-kD and 18-kD allergens as the hevein proprotein. The 46-kD and 110-kD had identical sequences which were unique from known latex proteins. We conclude that multiple latex proteins are allergens with hevein preprotein and a previously unidentified 46/110-kD protein being commonly recognized in health care workers.

Adolescent↗
PubMed1994

A 48-kilodalton Mycoplasma fermentans membrane protein induces cytokine secretion by human monocytes.

Mycoplasma fermentans is one of several Mycoplasma species that have been reported to stimulate tumor necrosis factor (TNF) secretion from monocytes. This activity has been associated primarily with the mycoplasma membrane fraction. In this article, we have characterized a membrane protein that stimulates TNF and interleukin 1 beta secretion. The TNF-releasing activity partitioned into the Triton X-114 detergent phase, suggesting that the molecules is hydrophobic. The secretion of TNF is elevated in the presence of serum, which suggests that a serum component may play a role in the interaction between this mycoplasma protein and monocytes. Treatment of monocytes with monoclonal anti-CD14 antibody had no effect on the levels of TNF-releasing activity. By using the monocyte Western blot (immunoblot) technique, we have determined the molecular mass of the active molecule to be 48 kDa. This molecule appears to be distinct from the recently described family of variable lipoproteins of M. fermentans. Mycoplasma particulate material treated with proteinase K lost all inducing activity, whereas lipoprotein lipase-treated samples retained some level of activity.

Antigens, CD↗
PubMed1994

Scientific assay methods as the basis for glove selection.

Allergies to latex proteins and glove chemicals are increasing in the clinical practice setting. Inasmuch as latex is ubiquitous in the health environment, individuals may be exposed to latex antigens by a number of different routes, including compromised skin, mucous membranes of the respiratory and urogenital tracts, and internally during surgery. As demonstrated by numerous research articles, the key factors that appear to play a role in acquired latex hypersensitivity are chemicals used in the manufacture of products; the level of residual latex proteins, and the presence of glove powder, which binds latex protein. Currently, devices and materials containing latex are not labeled, although this may be rectified by the FDA in the near future. Until products are labeled, it is important for physicians to familiarize themselves with the routes of sensitization, variations in assay methods, and the type and amount of allergen in products in order to select the safest product for patient use and personal protection.

Amino Acid Sequence↗
PubMed1994

Latex allergy--a clinical perspective.

Latex allergy has been increasingly recognized in the past 6 years. Defined risk groups are health-care workers, spina bifida children, and possibly food allergy patients. Powdered latex gloves and latex barium enema tips are products most commonly associated with allergy. Clinically, patients present with contact urticaria, allergic rhinoconjunctivitis, asthma, and anaphylaxis. At least 15 deaths are reported to have occurred because of latex allergic reactions. Severe occupational latex allergy can result in removal of the affected individual from the workplace. This will have important cost implications. The only presently available treatment of latex allergy is avoidance.

Health Occupations↗
PubMed1993

Fibronectin cell-binding domain triggered transmembrane signal transduction in human monocytes.

Fibronectin (Fn) fragments have recently been shown to stimulate tumor necrosis factor (TNF) secretion by human monocytes. In this study, we investigated the signal transduction mechanisms involved in Fn-induced TNF secretion. Treatment of human monocytes with Fn120, a chymotryptic cell-binding fragment of plasma Fn, failed to cause a detectable rise in Ca2+ mobilization. Fn120-induced TNF secretion could be inhibited with Ca2+ channel blockers. The protein kinase C (PKC) inhibitors H-7 and sphingosine inhibited the TNF-inducing activity of Fn120. HA1004 was used as a control for the isoquinoline sulfonamide derivatives and did not change Fn120-induced TNF secretion by monocytes. H-8 inhibited TNF secretion at higher concentrations. A calmodulin-dependent kinase inhibitor, W-7, was found to be effective, with 50% inhibition of Fn120-induced TNF secretion at 5 microM. The activation and translocation of PKC were measured directly. In unstimulated monocytes, approximately 70% of PKC activity was found in the cytosol and 30% in the membrane. Following the stimulation of monocytes with phorbol myristate acetate (100 nM), rapid and sustained translocation of PKC from the cytosol to the membrane was observed. The stimulation of monocytes with Fn120 triggered a rapid translocation of PKC within 2 to 5 min, followed by a return to normal levels within 8 min. These findings support the conclusion that Fn120-induced TNF secretion requires the activation of PKC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

Flash sterilization and instrument tape--an experimental study.

A letter appearing in the AORN Journal questioned whether flash sterilization is appropriate for instruments coded with color identification tape. The reply stated that porous, colored tape required a longer time to penetrate and sterilize the area beneath, and thus if it should peel off, the zone beneath might not be sterile. This conclusion was, as far as we can determine, reached by intuitive reasoning and not by experimental evidence. Therefore, the following experimental approach was undertaken to test the hypothesis. Spores on discs were placed between the color-code tape and a metal instrument. Exposure to heat (135 degrees C) and time (3 min.) was in a gravity displacement sterilizer. We then determined whether spore kill has been achieved. The test organism was B. stearothermophilus. None of the discs that were in contact with the instruments while being sterilized showed any growth. Thus, it appears that sterility can be achieved on the instrument surfaces that are beneath color-code tape in three minutes.

Equipment Contamination↗
PubMed1993

Protein kinase C activation in human monocytes: regulation of PKC isoforms.

The distribution of protein kinase C (PKC) isoforms and phorbol 12-myristate 13-acetate (PMA)-induced activation of PKC in human monocytes was investigated. Using Western blot analysis, PKC beta was found to be the most abundant isoform in monocytes. PKC beta was equally distributed in the cytosol and membrane. PKC-alpha was readily detectable and found predominantly in the cytosol. Little to no PKC-epsilon, gamma, delta, and zeta were observed. Following the treatment of monocytes with PMA, the physical translocation of PKC alpha from the cytosol to the membrane occurred over 60 min. PMA-induced translocation of PKC-beta was difficult to detect by Western blot. Fura-2 analysis demonstrated that PMA-induced PKC translocation was not accompanied by a net change in cytosolic calcium levels. Using histone as a substrate for PKC activity, an extremely rapid translocation of PKC-dependent histone phosphorylation (PKC-DHP) was induced by PMA. Cytosolic PKC-DHP activity decreased to undetectable levels within 8 min. In contrast, analysis of PKC-dependent endogenous substrate phosphorylation (PKC-DESP) showed a pattern with a time-course similar to that observed with Western blot. Thus, translocation of PKC-DESP but not PKC-DHP activity correlated with PKC-alpha as determined by Western blot. The data support the concept that PKC activity is substrate dependent and suggest that using one assay for the measurement of PKC activity may lead to erroneous conclusions.

Animals↗
PubMed1992

Fibronectin fragments stimulate tumor necrosis factor secretion by human monocytes.

Fibronectin (Fn) is a high molecular-weight glycoprotein that can influence many aspects of monocyte function. The purpose of this study was to determine whether Fn could stimulate monocyte tumor necrosis factor (TNF) secretion. Monocytes were isolated from the peripheral blood of healthy volunteers by density gradient centrifugation and adherence to plastic (2 h). Plasma Fn was purified from the blood by gelatin-Sepharose affinity chromatography. Monocytes were stimulated with Fn for 18 h and the supernatants were assayed for TNF activity using the L929 bioassay. Intact Fn stimulated the secretion of TNF in a dose-dependent manner. Intact Fn-induced TNF secretion by monocytes was inhibited (50%) but not eliminated by the addition of the R-G-D-containing peptide GRGDSP. Limited proteolysis of the Fn molecule using insoluble chymotrypsin resulted in a fragment preparation that was dramatically more stimulatory than the intact Fn preparation. High-performance liquid chromatographic (HPLC) purification of the fragments demonstrated that at least two fragments were capable of stimulating TNF secretion. Further purification by affinity chromatography and HPLC localized the stimulatory activity to the 120-kd cell-binding fragment. The possibility that the stimulatory activity was the result of endotoxin contamination was ruled out using macrophages from C3H/Hej mice. These results suggest that Fn fragments are potentially important molecules for activation of monocytes and may stimulate monocyte cytotoxic activity.

Animals↗
PubMed1991

Differentiation-inducing cytokine P48 exists in a membrane-associated form.

P48 is a recently described 48-kDa differentiation-inducing cytokine isolated from the culture medium of the human leukemia line Reh. P48 induces differentiation and cytolytic activity in the promyelocytic cell line HL-60, and stimulates the release of TNF-alpha and IL-1 from peripheral blood monocytes. In further studies designed to examine the biosynthesis and function of P48, surface immunofluorescence flow cytometry analysis as well as 125I surface labeling and immunoprecipitation, revealed the presence of P48 on the surface of Reh cells. Triton X-114-treated Reh cells were partitioned into detergent and aqueous phases and separated by SDS-PAGE. Western blot analysis revealed that P48 partitioned exclusively into the detergent phase, suggesting an integral membrane association. Reh cells fixed with paraformaldehyde, but not K562 or P815, were able to stimulate the release of TNF-alpha from peripheral blood monocytes in a manner similar to that of secreted P48. Isolated plasma membranes from Reh cells could also stimulate TNF-alpha release. This TNF-alpha-releasing activity could be removed from detergent solubilized Reh membranes by immunoaffinity chromatography on an anti-P48 column. This study suggests that, in addition to being secreted into the culture medium, P48 is expressed on the surface of Reh cells in a biologically active form. The membrane form of P48 may be 1) a final maturation step before secretion or 2) a cell membrane-associated form that may be analogous to the membrane forms of TNF-alpha and IL-1.

Blotting, Western↗
PubMed1989

P48 induces tumor necrosis factor and IL-1 secretion by human monocytes.

Bacterial products are potent stimulators of TNF and IL-1 release, however, the factors that regulate cytokine secretion in the absence of bacterial products are not well defined. P48 is a cytokine recently identified in the supernatant of the human null cell leukemia cell line Reh, which induces differentiation and cytolytic activity in HL-60 cells. P48 has been purified to homogeneity and is distinct from TNF-alpha TNF-beta, IFN-gamma, IL-6, and macrophage CSF. In the present study we examined the ability of P48 to stimulate cytokine release by human peripheral blood monocytes. P48 stimulated the secretion of TNF and IL-1 in a dose-dependent manner. Priming the monocytes with IFN-gamma enhanced P48-induced cytokine release but was not a requirement for secretion. Cytokine secretion was in response to P48 and was not caused by endotoxin contamination. The cytokine-inducing activity of P48 was extremely sensitive to heat treatment but could not be eliminated by using polymyxin B. Polyclonal antisera to P48 completely blocked the cytokine-inducing activity. P48 may be an important new member of the cytokine network involved in the regulation of cytokine secretion by monocytes.

Animals↗
PubMed1989

Modulation of macrophage fibronectin secretion by LPS.

The secretion of fibronectin (Fn) by rat peritoneal macrophages was found to be down-regulated by LPS. A sensitive ELISA was used to quantitate both substrate-attached and supernatant Fn. Thioglycollate-elicited peritoneal exudate cells were observed to release a considerable amount of Fn during the adherence procedure for macrophage purification. After this procedure, macrophage Fn levels peaked within 2 hr and then declined steadily to baseline levels by 96 hr. Fn release by exudate cells during adherence purification was less affected by cycloheximide treatment than was subsequent Fn secretion by purified macrophages. Macrophages elicited with thioglycollate and P. acnes displayed enhanced Fn secretory activity when compared with resident unstimulated cells. Exposure to lipopolysaccharide (LPS) suppressed the levels of immunoreactive Fn in supernatants of elicited cells. This inhibition was shown to be dose-dependent and most significant after 24 hr of incubation. The inclusion of polymyxin B in the culture medium did not reverse the LPS-induced inhibition of Fn production but did prevent LPS stimulation of interleukin-1 secretion in the macrophage cultures. These observations demonstrate that Fn secretion by macrophages is regulated according to the functional state of the cell.

Animals↗
PubMed1987

Synergistic induction of interleukin-1 by endotoxin and toxic shock syndrome toxin-1 using rat macrophages.

We studied interleukin-1 (IL-1) secretion by rat peritoneal exudate macrophages stimulated with purified toxic shock syndrome toxin-1 (TSST-1). TSST-1 was observed to be a more potent inducer of IL-1 than was endotoxin. The induction of IL-1 secretion by TSST-1 was not blocked by polymyxin B but could be blocked by monoclonal antibodies directed against TSST-1. Synergistic induction of IL-1 was observed when the cells were stimulated with TSST-1 and endotoxin. The sequence of addition was found to be important for the synergistic response. Enhanced IL-1 production was observed only when macrophages were exposed to endotoxin before or simultaneously with TSST-1. Prior exposure of macrophages to TSST-1 had no enhancing effect on endotoxin-induced IL-1 secretion. We conclude that stimulation of the macrophage by endotoxin enhances the responsiveness of the cells to TSST-1 and may thereby play a role in the pathogenesis of toxic shock syndrome.

Animals↗