Murine macrophages stimulated with central and peripheral nervous system myelin or purified myelin proteins release inflammatory products.

Macrophage inflammatory products including tumor necrosis factor (TNF) and interleukin-12/p40 are implicated in demyelinating diseases such as multiple sclerosis (MS), Guillain-Barré syndrome, and animal models experimental autoimmune encephalomyelitis and neuritis. The macrophage product angiotensin converting enzyme (ACE) is released during inflammation. ACE can also be elevated in MS. We investigated the ability of central (CNS) and peripheral nervous system (PNS) myelin to stimulate TNF, interleukin-12, and ACE production by murine macrophages. Both CNS and PNS myelin and purified myelin basic protein and P2 protein induced release of these products. Direct stimulation by myelin may represent a mechanism of inducing release of macrophage products in inflammatory demyelination or neural injury.

The seroprevalence of the rubeola antibody in a prenatal screening program.

OBJECTIVE: To evaluate the seroprevalence of the rubeola (measles) antibody in several obstetric populations. METHODS: In this cross-sectional study, women presenting for prenatal care underwent measurement of antibodies to the rubeola virus. The study population presented for care at either an urban medical center (group I) or a suburban medical center (group II). These groups were divided further into those receiving care in a resident-supervised clinic (A) and those in a private-practice setting (B). RESULTS: A total of 768 women were tested. Seventy-five (9.8%) women had rubeola antibody titers less than or equal to 0.13 and were classified as seronegative. The lowest percentage of seronegative women (3.2%) was found at the urban resident-supervised clinic site. The highest percentage of seronegative women (20.5%) was found in the suburban resident-supervised clinic site. Women classified as seronegative were younger, with a mean age of 25.0 years. No significant difference was observed based on gravidity, parity, or care received in an urban versus suburban private-practice setting. CONCLUSION: We suggest that an appreciable number of women presenting for prenatal care may lack antibodies to the rubeola virus. In the interest of personal and public health, populations believed to be at risk may benefit from ongoing surveillance of immune status and appropriate vaccination. Additional study is necessary to define best those groups that would benefit from surveillance and vaccination.

The effect of renal function on serum levels of CA 125.

OBJECTIVE: Serum assays for CA 125 are used to monitor disease status in patients undergoing treatment for epithelial ovarian cancer. While a number of benign gynecologic as well as benign and malignant nongynecologic conditions are associated with CA 125 elevations, the established "normal" range describes a healthy population of women. The metabolism and clearance of CA 125 is not well understood. Because mild degrees of renal impairment frequently occur in ovarian cancer patients, we investigated the effect of impaired renal function on basal CA 125 in a population of female dialysis patients. METHODS: Twenty-five women on hemodialysis were selected at random. Patients ranged in age from 29 to 87 years. Renal disease was secondary in most cases to diabetes mellitus or hypertension. The creatinine clearance was less than 10 cc/min for all patients. The duration of dialysis ranged from 3 months to 14 years. Serum levels of CA 125 were measured using monoclonal antibodies in an immunoradiometric assay. RESULTS: The mean of duplicate determinations for 23 of 25 (92%) patients fell within the normal range for otherwise healthy women (< 35 U/ml). There was no apparent correlation between CA 125 level and age, menopausal status, BUN, serum creatinine, adequacy of dialysis, or primary underlying diagnosis. Of the 2 patients (8%) with CA 125 levels above the normal range, 1 was premenopausal and the other was postmenopausal; their CA 125 elevations were marginal (49.81 and 50.51). CONCLUSIONS: The results of this study demonstrate that even marked renal insufficiency is not itself associated with significant elevations of CA 125 above the normal range selected for otherwise healthy women. The development of renal insufficiency during treatment for ovarian cancer should not alter the interpretation of serum levels of CA 125.

Assessment of the Abbott IMx assay system for the measurement of human chorionic gonadotropin levels in the treatment of ectopic pregnancy.

The rapid, accurate determination of serum human chorionic gonadotropin (beta-hCG) levels in the 900- to 2000-IU/L range is a critical element in the treatment of patients with suspected ectopic pregnancy. Using the Abbott IMx system (Abbott Laboratories, North Chicago, Ill), beta-hCG levels can be determined on an undiluted sample up to 1000 IU/L. A sample with beta-hCG level greater than 1000 IU/L is automatically diluted and the diluted sample redetermined. Unfortunately, employing a 1:200 fixed dilution can produce a working sample that contains an beta-hCG concentration that does not fall on a linear portion of the standard curve (<7.5 IU/L). This results in a calculated beta-hCG concentration (200 x observed value) that has high error (coefficient of variation up to 21.8%). Additionally, interfering substances in the reagents, which vary in quantity from lot to lot of reagents, further confound accurate beta-hCG determination by the system. Consequently, the Abbott IMx assay system cannot be used as recommended by the manufacturer for routine measurement of serum beta-hCG in the 900- to 2000-IU range. An alternate protocol employing at 1:10 dilution would allow a more accurate beta-hCG determination.

Interference by human anti-mouse antibody in two-site immunoassays.

Studies with goat and rabbit anti-mouse antibody, as models of human anti-mouse antibody (HAMA), have shown that several of the commonly used two -site immunoassays (e.g., for CA-125, carcinoembryonic antigen, choriogonadotropin, lutropin, hepatitis B surface antigen, thyrotropin) are susceptible to interference by this type of bridging heterophile antibody. In most cases the interference can be blocked by incubation with mouse IgG. We studied HAMA interference in an assay of hepatitis B surface antigen by using HAMA-positive sera from a transplant patient given OKT3 and from a cancer patient given CYT-103 (modified antibody B72.3). The HAMA interference attributable to the OKT3 could be blocked by incubation with mouse IgG at room temperature. In contrast, the interference caused by the B72.3-induced HAMA could be blocked by prolonged incubation with high concentrations of the B72.3 antibody at 4 degrees C. A limited survey of 50 hospital patients selected without conscious bias revealed two HAMA-positive patients, only one of whom was known to have been exposed to mouse immunoglobulin. HAMA interferences are currently a minor problem in routine laboratory medicine, but the increasing use of diagnostic and therapeutic products involving mouse-origin monoclonal antibodies will make the detection and elimination of HAMA interferences an important part of laboratory practice in the future.

Delineation of false-positive HIV antibody response in patients with renal failure and history of multiple transfusions.

Four patients with a history of multiple blood transfusions who awaited renal transplantation were tested for human immunodeficiency virus (HIV) infection and found to be positive on enzyme immunoassay (EIA) and negative on Western blot. None of these patients had any clinical evidence of HIV infection. Absorption of these patients' sera with B-lymphoblastoid cell lines (B-LCL) positive for the serologic specificities DR3, DR4 (Dw4, Dw10, Dw14), and DR5 resulted in EIAs that were negative for HIV. Treatment of the B-LCL with an anti-DR monoclonal antibody (L243) interfered with the absorption of the serum sample by B-LCL. This indicates that the initial false-positive EIA results may be due to HLA antibodies. Furthermore, it was shown that these HLA antibodies are not limited in specificity to the HLA type of the host cell used in the preparation of the EIA reagents, but can consist of other DR specificities.

Electron microscopic cytochemical localization of Ca-ATPase in toad urinary bladder.

The calcium-regulating enzyme calcium adenosine triphosphatase (Ca-ATPase) was localized in the epithelium of amphibian urinary bladder by the one-step electron microscopic cytochemical procedure. The enzyme was identified along the basolateral border of the epithelial cells that comprise the bladder mucosa. The electron-dense precipitate indicating Ca-ATPase activity was seen in association with the outer leaflet of the basolateral plasmalemmae. Intracellularly, Ca-ATPase activity was seen in association with the mitochondrial matrix of the mitochondria-rich cells. Ca-ATPase was not seen along the apical microvillated border. Enzyme activity was also not seen after incubation in substrate-free media, calcium-free media, or incubation in the presence of vanadate. However, Ca-ATPase activity was evident when the calcium in the standard reaction medium was deleted in favor of magnesium. Addition of antidiuretic hormone (ADH; vasopressin) increased both the basolateral Ca-ATPase reaction and the mitochondrial reaction. Such data appear to indicate further that changes in cytosolic calcium ion concentration take place during the response of amphibian urinary bladder to the polypeptide hormone vasopressin.

Phenytoin hypersensitivity: a case of severe acute rhabdomyolysis.

A 22-year-old black man was hospitalized with fever, rash, myalgias, and marked periorbital and facial edema three months after beginning phenytoin therapy. His hospital course was marked by an initial serum creatine phosphokinase level of 85,000 IU/liter, which rose to a peak value of 242,000 IU/liter on the third hospital day and a striking eosinophilia (8,400/microliter). Muscle biopsy revealed only early fiber necrosis with partial dissolution of the sarcoplasm without evidence of inflammation, vasculitis, regeneration, or parasitic infection. When therapy with phenobarbital, a structural congener of phenytoin, was begun, the patient had an exacerbation of his rash and became febrile again.

t-Butyl hydroperoxide alters fatty acid incorporation into erythrocyte membrane phospholipid.

Because the ability of cells to replace oxidized fatty acids in membrane phospholipids via deacylation and reacylation in situ may be an important determinant of the ability of cells to tolerate oxidative stress, incorporation of exogenous fatty acid into phospholipid by human erythrocytes has been examined following exposure of the cells to t-butyl hydroperoxide. Exposure of human erythrocytes to t-butyl hydroperoxide (0.5-1.0 mM) results in oxidation of glutathione, formation of malonyldialdehyde, and oxidation of hemoglobin to methemoglobin. Under these conditions, incorporation of exogenous [9,10-3H]oleic acid into phosphatidylethanolamine is enhanced while incorporation of [9,10-3H]oleic acid into phosphatidylcholine is decreased. These effects of t-butyl hydroperoxide on [9,10-3H]oleic acid incorporation are not affected by dissipating transmembrane gradients for calcium and potassium. When malonyldialdehyde production is inhibited by addition of ascorbic acid, t-butyl hydroperoxide still decreases [9,10-3H]oleic acid incorporation into phosphatidylcholine but no stimulation of [9,10-3H]oleic acid incorporation into phosphatidylethanolamine occurs. In cells pre-treated with NaNO2 to convert hemoglobin to methemoglobin, t-butyl hydroperoxide reduces [9,10-3H]oleic acid incorporation into phosphatidylcholine by erythrocytes but does not stimulate [9,10-3H]oleic acid incorporation into phosphatidylethanolamine. Under these conditions oxidation of erythrocyte glutathione and formation of malonyldialdehyde still occur. These results indicate that membrane phospholipid fatty acid turnover is altered under conditions where peroxidation of membrane phospholipid fatty acids occurs and suggest that the oxidation state of hemoglobin influences this response.

Aminoglycoside toxicity: pH dependent inhibition of ADH response.

The effect of aminoglycoside antibiotics on the response of the isolated toad urinary bladder to antidiuretic hormone (ADH) was investigated. Gentamicin and neomycin both acidify the serosal bathing solution and cause a dose-dependent inhibition of the hydroosmotic response to ADH, while streptomycin has minimal effect on media pH and causes no inhibition of the response to ADH. Detailed studies employing gentamicin indicate that acidification stimulates production of PGE2, a known inhibitor of the hydroosmotic response of the toad bladder to ADH. When media pH is rigidly controlled or PGE2 production is inhibited by indomethacin, the inhibitory effect of gentamicin on the response to ADH is ameliorated. These studies suggest that the defect in renal concentrating ability seen as part of aminoglycoside nephrotoxicity could be due, in part, to an acidification-induced, prostaglandin-mediated resistance to the action of ADH.

Detection of the ovulatory luteinizing hormone (LH) surge with a semiquantitative urinary LH assay.

We examined blood concentrations of ovarian steroid hormones (E2, P) and serum LH concentrations to establish that the Ovu-STICK assay reliably reflects endocrine events in the periovulatory period. In all 16 cycles studied, which included 2 cycles in which the women received CC, the ovulatory surge of LH was detected with the use of the Ovu-STICK assay. In contrast, BBT monitoring correctly predicted the ovulatory event in only half the cycles.

Activation of actin-containing microfilaments by vasopressin in the amphibian urinary bladder epithelium: a fluorescent study using NBD-phallacidin.

The effect of an antidiuretic hormone (ADH, vasopressin) on the microfilament system of the toad urinary bladder lumenal epithelium was investigated using NBD-phallacidin (NBD-ph). The latter material is a specific fluorescent label for F actin. In the presence of an osmotic gradient, both ADH and cyclic adenosine monophosphate (cAMP) appear to induce the polymerization of monomeric actin into F actin-containing microfilaments. The latter may then be involved in the morphological changes, including the formation of lateral intercellular lakes, associated with the typical hydroosmotic response.

Characterization of the phosphorylated intermediate of the K+-ouabain-insensitive ATPase of the rabbit colon brush-border membrane.

The rabbit colon brush-border membrane possesses a unique K+-stimulated, ouabain-insensitive ATPase. This enzyme is similar to previously described potassium-transporting enzymes such as the ubiquitous (Na + K)-ATPase and the gastric (H+ + K+)-ATPase in forming a phosphorylated intermediate whose rate of dephosphorylation is accelerated by K+. The molecular weight of the phosphorylated polypeptide subunit of the colon membrane enzyme is 114,000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The release of 32Pi from the 32P-labeled ATPase at alkaline pH and in the presence of hydroxylamine at pH 5.0 suggests that the phosphorylated enzyme intermediate is an acyl phosphate. These results indicate that the phosphorylated intermediate of the colon brush-border membrane is similar in chemical nature and molecular weight to the phosphorylated intermediates of other cation-transporting ATPases.

Isolation of brush-border membrane from the rabbit descending colon epithelium. Partial characterization of a unique K+-activated ATPase.

The mechanisms of ion movement across the apical membrane of the colon have previously been investigated only in intact tissue. To investigate these mechanisms directly, we have undertaken the isolation and characterization of the apical brush-border membrane of the rabbit descending colon. The purification protocol consists of an initial isolation of single epithelial cells after dissociation of the mucosal layer in EDTA, a high pH (8.3), low ionic strength homogenization of the cells, and differential centrifugation and separation of apical membrane from nuclei, and filamentous material on a 7.5% Percoll gradient. A 20-fold enrichment in alkaline phosphatase (an apical membrane enzyme marker) specific activity over the initial homogenate value is observed in the final membrane fraction. This fraction also contains a K+-activated, pH 7.8, optimum ATPase (20 times purified over homogenate) with the following properties: 1) low Kact (2 X 10(-4) M) for K+; 2) resistance to high ionic strength (1 M Tris) solubilization; 3) competitive inhibition by Na+ (K1 = 14 mM), no activation by Na+; 4) inhibition by orthovanadate (K1 = 40 nM), but no effect of oligomycin (20 micrograms/ml of protein) or ouabain (10(-3) M); and 5) a K+-sensitive phosphorylated intermediate. These characteristics suggest that this membrane-bound ATPase is distinct from other known ATPases including the Na+ + K+ - ATPase-Na+ pump of the basolateral membrane.

Regulation of cyclic AMP metabolism in the rat erythrocyte during chronic beta-adrenergic stimulation. Evidence for calmodulin-mediated alteration of membrane-bound phosphodiesterase activity.

The regulation of cyclic AMP metabolism in the rat erythrocyte has been investigated during chronic exposure to the beta agonist isoproterenol. A triphasic response is observed: 1) an acute increase in cyclic AMP to levels four- to fivefold greater than basal, maximal by 1 minute (Phase I); 2) a gradual decline in cAMP content to levels near basal during the next 15-20 minutes (Phase II) and a second sustained rise in cAMP, maximal by 60 minutes, to a concentration greater than that observed during the first minute (Phase III). Extensively washed Phase II and Phase III cells are refractory to a second challenge by isoproterenol. In phosphodiesterase-inhibited intact Phase II and III cells adenylate cyclase activity is maximally activated. Isoproterenol has no effect on soluble phosphodiesterase activity but increases membrane-bound phosphodiesterase activity 3- and 2.2-fold in Phase II and Phase III cells, respectively. The activation of this membrane-bound enzyme activity appears to be mediated by the calcium-dependent regulatory protein, calmodulin, because 1) the amount of exogenous calmodulin required to achieve half-maximal activation of membrane-bound phosphodiesterase is 3.7, 2.0, and 1.2 micrograms in control, Phase III and Phase II membranes, respectively; and 2) there is less calmodulin in membrane-free lysates prepared from Phase II cells than control cells. These data support the idea that the major mechanism regulating cAMP content in the rat erythrocyte during chronic isoproterenol stimulation is the membrane-bound phosphodiesterase and that there is a translocation of calmodulin from the cytoplasm to the membrane during hormone stimulation.

Studies of the Ca2+ transport mechanism of human erythrocyte inside-out plasma membrane vesicles. I. Regulation of the Ca2+ pump by calmodulin.

Calcium accumulation by human erythrocyte inside-out vesicles was linear for at least 30 min in the presence of ATP. In untreated inside-out vesicles, 3.76 +/- 1.44 nmol of calcium/min/unit of acetylcholinesterase were transported, compared with 10.57 +/- 2.05 (+/- S.D.; n = 11) in those treated with calmodulin. The amount of calmodulin necessary for 50% activation of Ca2+ accumulation was 60 +/- 22 ng/ml (+/- S.D.; n = 4). The Km (Ca2+) for calmodulin-stimulated accumulation was 0.8 +/- 0.05 microM (+/- S.D.; n = 5) using Ca2+ /ethylene glycol bis(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid (EGTA) buffers, or 25 microM with direct addition of unbuffered calcium. In the absence of calmodulin, these values were 0.4 and 60 microM, respectively, Km (ATP) values of 90 and 60 microM in the presence and absence of calmodulin, respectively, were measured at constant magnesium concentration (3 mM). In the presence of calmodulin, a broad pH profile is exhibited from pH 6.6 to 8.2. Maximal calcium accumulation occurs at pH 7.8. In the absence of calmodulin, the pH profile exhibits a linear upward increase from pH 7.0 to 8.2. The (Ca2+-Mg2+)-ATPase activity, measured under identical conditions, was 2.40 +/- 0.72 nmol of Pi/min/unit of acetylcholinesterase in the untreated vesicles and 11.29 +/- 2.87 nmol of Pi/min/unit of acetylcholinesterase (+/- S.D.; n = 4) in calmodulin-treated vesicles. A stoichiometry of 1.6 Ca2+/ATP hydrolyzed was determined in the absence of calmodulin; in the presence of calmodulin, this ratio was decreased to 0.94 Ca2+/ATP hydrolyzed.