Use of monoclonal antibodies to identify the distribution of A and M epitopes on smooth Brucella species

The smooth types of Brucella species express two lipopolysaccharides (LPSs) (A and M) which are antigenically distinct. Their existence as cross-reactive antigenic complexes makes definitive serology difficult. Murine hybridomas were produced and selected for their ability to produce monoclonal antibodies to the specific A- or M-LPS epitopes. The specificity of the monoclonal antibodies was determined by microplate enzyme-linked immunoassay, binding inhibition assay, microplate agglutination, and dot blot assay. Monoclonal antibody 12AE6 was specific for an epitope on the A LPS of Brucella spp., which was also expressed on Yersinia enterocolitica O:9. A unique epitope of M LPS was detected by monoclonal antibody 33.1.5. The two monoclonal antibodies did not exhibit cross-reactions when assayed with whole Brucella cells or purified M- and A-LPS preparations. Cross-reactive serology with polyvalent sera can be attributed to the presence of common antigenic determinants on both molecules. The use of A- and M-LPS-specific monoclonal antibodies has the potential to replace the more laborious methods involved in the production of monospecific sera.

The effect of exercise on thrombin and plasmin generation in middle-aged men

Plasma levels of B beta 15-42 peptide and fibrinopeptide A (FPA) were measured as indicators of plasmin-mediated fibrin(ogen)olysis and thrombin activity of fibrinogen in 34 middle-aged men, at rest and following a standard exercise test. In the group as a whole no significant changes in B beta 15-42 or FPA were noted after exercise. When the group was subdivided into men with (n = 20) and without (controls n = 14) coronary heart disease, exercise-stimulated thrombin and plasmin generation was found only in the control group who exercised for a significantly longer duration. The rise in B beta 15-42 was related to both the intensity and duration of exercise. Similar increases in plasma fibrinolytic activity (fibrin plate) occurred in both groups and no other differences in the components of the fibrinolytic system (plasminogen, alpha 2-antiplasmin, fibrin degradation product) were noted either after exercise or between the groups. Exercise in normal middle-aged men is associated with modest thrombin and plasmin activation.

Preliminary study of a Mycobacterium leprae bacterin vaccine in a human volunteer population in a nonendemic area

Seventeen volunteers who had never resided in areas with significant transmission of leprosy (Hansen's disease) were inoculated intradermally with 1.5 X 10(8) killed, purified armadillo-derived Mycobacterium leprae in a standardized preparation being tested for possible vaccine use. The peak of local skin responses, consisting of induration with or without ulceration similar to the post-lepromin Mitsuda reaction, occurred between the 21st and 28th days after injection. The maximum mean induration diameter was 17.2 mm, the minimum, 6.1 mm. Sera tested with the ELISA technique revealed no humoral response to either the sonicated bacilli, M. leprae-specific phenolic glycolipid I antigen, or three semi-synthetic analogues reactive with lepromatous patients' sera. The dose of M. leprae inoculated appeared to be safe and without unacceptable reactions at the injection site. One volunteer developed a generalized skin rash parallel to the local reaction, but the relationship of the former to the inoculation was unclear.

Effect of insulin therapy on coagulation and platelet function in type II (non-insulin-dependent) diabetes mellitus

Twenty type II (non-insulin-dependent) poorly controlled diabetics had tests of coagulation and platelet function performed while receiving high-dose sulphonylurea therapy and at 1 and 3 months following their conversion to insulin. Although no overall change in glycaemic control (assessed by glycosylated haemoglobin) was noted, a reduction in thrombin generation was observed, as judged by a significant fall in fibrinopeptide A concentrations. No changes in factor VIII coagulant activity (VIII:C), factor VIII-related antigen or antithrombin III were found. Glycosylated haemoglobin concentrations showed significant correlations with antithrombin III and factor VIII:C, suggesting that improved glycaemic control might lead to an improvement of antithrombin III function and lower factor VIII:C concentrations. No changes in platelet function were detected. The introduction of an insulin regimen that improves glycaemic control might lead to a reversal of the 'hypercoagulable state' found in type II diabetes.

Utilization of the platelet release reaction in the blood compatibility assessment of polymers

The release reaction is directly associated with platelet adhesion and aggregation, which are primary events leading to thrombus formation following contact of blood with artificial surfaces. This investigation examined the release reaction from the alpha granules of platelets after blood-polymer interaction, and utilized the measurement of beta-thromboglobulin (BTG), a platelet-specific protein, in the assessment of the in vitro blood compatibility of polymers. A radioimmunoassay was used, to determine the release of BTG following contact of blood with tubes of siliconized glass and polypropylene and flat sheets of poly(vinyl chloride) and silicone rubber. Polypropylene tubes caused less release of BTG than those of siliconized glass and silicone rubber induced less BTG release than poly(vinyl chloride). The investigation indicates a role for BTG measurement in blood compatibility assessment.

Porins of Brucella species

The outer membrane of Brucella species contains two major proteins, denoted as group 2 and group 3 proteins (Verstreate et al., Infect. Immun. 35:979-989, 1982). We reconstituted proteoliposomes from the purified proteins and egg phosphatidylcholine and showed that group 2 proteins, but not a group 3 protein, had the porin activity. The influx rates of sugars of various sizes into the proteoliposomes indicated that the porin channels had apparent diameters in a range comparable to that of Escherichia coli OmpF porin and that the channels were predominantly open. Among different Brucella species, there were small but detectable differences in the channel diameter, and it was possible to explain the differential sensitivity of several Brucella species to diagnostic dyes on the basis of these observed differences.

Field evaluation of an ELISA to detect antibody in leprosy patients and their contacts

Previous studies have detected circulating antibody in leprosy using a variety of difficult laboratory methods. We have developed a simpler method for detecting antibody by ELISA, using autoclaved Mycobacterium smegmatis as the antigen. Evaluation was performed on eluates from 25 microliter aliquots of finger-prick blood dried on filter-paper disks in two high-incidence populations in Ponape, Micronesia. Among 228 nonleprosy cases bled in 1980 and rebled and re-examined in 1982: a) for those who had been ELISA positive two years earlier, the leprosy attack rate during the intervening two years was at least twice as high as among those who had been negative, and we estimate that shortening the screening interval to one year plus doing confirmatory retests on new sero-converters would increase the relative risk (or "predictive power") to over sixfold, including all impending multibacillary cases; b) elevated antibody levels were detected up to two years prior to clinical onset of disease in 70% of new cases; and c) both asymptomatic conversion (rising titer) and reversion (falling titer) were observed. Among 150 biopsy-proven cases, ELISA results suggest that fall of titer in most uncomplicated paucibacillary cases was rapid (months), but in multibacillary cases was more gradual (years), probably paralleling responses to treatment with titers rising in reactivation. These results suggest that this technique, with an improved antigen, may be useful in leprosy control programs, both for detecting candidates for preventive treatment and for following responses to therapy.

Development of an ELISA for detection of antibody in leprosy

An ELISA system was developed for detection of antibodies in leprosy using whole cells of bacteria as an antigen. Whole cells of M. smegmatis, M. vaccae, M. scrofulaceum, M. leprae, C. diphtheriae, and C. xerosis were compared. M. smegmatis was the most reactive against lepromatous sera with OD492 readings 1.5 times and five times higher than the others. In addition, when M. smegmatis were coated to microtiter plates with a volatile ammonium acetate/carbonate buffer and air dried, the antigen coating was found to be three times more reactive than antigen coated with nonvolatile Na borate buffer. Autoclaving M. smegmatis increased the reactivity with lepromatous sera 1.4- to 2.3-fold. M. leprae was found to be 4-10 times more reactive than autoclaved M. smegmatis. Autoclaving M. leprae did not increase reactivity. Antibody titers of some lepromatous sera had endpoint titers of greater than 1:10,000. Both antihuman IgG and antihuman IgA, IgM, and IgG combined conjugates were found to be equally effective in detecting high levels of antibody in patients with multibacillary diseases.

Plasma fibrinopeptide A and beta-thromboglobulin in patients with chest pain

Plasma levels of beta-thromboglobulin (BTG) and fibrinopeptide A (FPA), markers of platelet release and thrombin generation respectively, were measured in 48 patients within 3 days of admission to hospital for acute chest pain. Twenty-one patients had a confirmed myocardial infarction (MI); 15 had unstable angina without infarction; and 12 had chest pain due to noncardiac causes. FPA and BTG were also measured in 23 control hospital patients of similar age. Mean plasma BTG levels were not significantly different in the 4 groups. Mean plasma FPA levels were significantly higher in all 3 groups with acute chest pain when compared to the control subjects (p less than 0.01), but there were no significant differences between the 3 groups. Increased FPA levels in patients with acute chest pain are not specific for myocardial infarction, nor for ischaemic chest pain.

Prognostic value of beta-thromboglobulin in patients with transient cerebral ischaemia

Plasma levels of beta-thromboglobulin (BTG) and fibrinopeptide A (FPA), markers of platelet alpha-granule release and thrombin generation respectively, were measured in 27 subjects with transient cerebral ischaemic attacks (TIA), 43 age-matched controls, and 32 young controls. BTG and FPA were both higher in elderly controls than in young controls. BTG was higher in TIA subjects than in age-matched controls and higher in the 12 TIA subjects who had further vascular events in the next year than in those who had no further events. FPA was not significantly associated with TIA or with further events. These results support a relationship between platelet activation and TIA and suggest that BTG levels indicate a group at higher risk of further vascular events.

Abnormal blood viscosity and haemostasis in long-standing retinal vein occlusion

Blood viscosity and several haemostatic factors were measured in 42 patients with long-standing retinal vein occlusion and 33 control subjects. Blood viscosity, haematocrit, plasma viscosity, fibrinogen, fibrinopeptide A, and beta-thromboglobulin were increased in the 20 subjects with capillary nonperfusion or new vessels, but not in the 22 subjects without these complications. Patients with nonperfusion or new vessels also had a lower platelet count than patients without complications. Increased levels of factor VIII antigen and decreased levels of antithrombin III were found in the retinal vein occlusion group as a whole. These findings suggest that blood viscosity, platelets, and coagulation may be involved in retinal vein occlusion and its vascular complications.

Factor IX thrombogenicity: in vivo effects on coagulation activation and a case report of disseminated intravascular coagulation

An episode of defibrination with bleeding following high dose Edinburgh Factor IX (D.E.F.IX) replacement in a patient with haemophilia B undergoing knee joint replacement is reported. We have also monitored plasma fibrinopeptide A levels in patients with haemophilia B following ten standard doses of D.E.F.IX (15-20 u/kg) and have been unable to document any change. Activation of the coagulation system, as previously noted, appears to be related to the use of Factor IX concentrates in high doses.

Beta-thromboglobulin and platelet counts - effect of malignancy, infection, age and obesity

Plasma levels of beta-thromboglobulin (BTG) and platelet count were studied in 69 control subjects, 19 patients with operable abdominal malignancy, and 9 patients with acute bacterial infection. In control subjects there was a significant rise in BTG and fall in platelet count with age, and a negative correlation of BTG with obesity. BTG and platelet count were normal in patients with operable malignancy, but significantly increased in patients with acute bacterial infection. These effects must be considered in studies of BTG and thrombosis.

Plasma fibrinopeptide A and beta-thromboglobulin in pre-eclampsia and pregnancy hypertension

Increased plasma levels of beta-thromboglobulin (beta TG) and fibrinopeptide A (FPA), markers of platelet release and thrombin generation respectively, were measured in normal women, women taking oral contraceptives, normal pregnancy and pregnant women with hypertension or pre-eclampsia. No significant increases in beta TG or FPA were found in women taking oral contraceptives. Significantly increased concentrations of beta TG, but not FPA, were found in normal pregnant women in the second and third trimester of pregnancy when compared with non-pregnant age-matched controls. In eleven women with pregnancy hypertension and thirteen women with pre-eclampsia significantly elevated levels of both beta TG and FPA were found when compared with age, parity and gestation-matched pregnant controls. Although the mean value for both beta TG and FPA in the group with pre-eclampsia was higher than the group with pregnancy hypertension, the difference was not statistically significant. These findings provide additional evidence that pre-eclampsia and pregnancy hypertension are associated with activation of the coagulation system and the platelet release reaction.

Effects of the non-selective beta-adrenoceptor blocking agent, carteolol, on platelet function, blood coagulation and viscosity

We have studied the effect of a new beta-adrenergic blocker, carteolol, on platelet function, blood coagulation and viscosity in 10 healthy male volunteers. Following carteolol (5 mg orally) we were able to demonstrate significant inhibition of platelet aggregation to ADP (p less than 0.05) and adrenaline (p less than 0.01) after 5 hours, but not at 2 or 24 hours. This maximum inhibition of platelet aggregation corresponded to peak plasma concentrations of carteolol measured. The platelet release reaction, as measured by plasma levels of the platelet specific protein beta-thromboglobulin (BTG) was unaltered and there was no significant effect on a panel of coagulation tests or on blood viscosity.

Methylation of nucleosomal and nuclease sensitive DNA

The proportion of cytosines methylated in the DNA of nucleosome oligomers and of core particles appears indistinguishable from that of total nuclear DNA from CHO cells. However the DNA in nucleoprotein which is initially released from nuclei by treatment with very low levels of micrococcal nuclease and the first 10% of material rendered acid soluble by treatment of nuclei with DNase I are enriched 2 fold in their content of 5 methylcytosine. (Cessation of hydrolysis by nuclease occurs concomitantly with precipitation of nucleosomal core particles).

Poly(A)-binding RNAs from nuclei and polysomes of BHK-21 cells

The presence in nuclei and cytoplasm of cultured BHK-21/C13 cells (baby hamster fibroblasts) of RNA species with high affinity for poly(A) was detected using either a Millipore-poly(A)-binding assay or columns of poly(A)-Sepharose 4B. The nuclear species which labels rapidly is metabolically unstable and appears to be a specific subclass of heterogenous nuclear RNA. Digestion with T1 RNAase gives rise to a low level (1%) of oligonucleotide fragments of a disperse size range which are relatively rich in uridylate residues. The cytoplasmic species with affinity for poly(A) is similar in size to polyadenylated messenger RNAs and also associates with polysomes. However it appears to be distinct from the polyadenylated messenger RNAs by virtue of an unusual base composition and relative metabolic instability.