Search PubMed⌕ Search

Biomedical subjects

A Hohmann

Publications and source records attributed to A Hohmann.

At least 19 recordsLinked to original sources
PubMed1992

Distribution of two common idiotypes of anticardiolipin antibodies in sera of patients with primary antiphospholipid syndrome, systemic lupus erythematosus and monoclonal gammopathies.

The frequency of two common idiotypes of anticardiolipin antibodies (aCL) was determined in sera from three groups of subjects, patients with systemic lupus erythematosus (SLE), with primary antiphospholipid syndrome (PAPS) and with monoclonal gammopathies (MG), as compared to normal population. The idiotype 1.10, which was derived from a patient with active SLE and antiphospholipid syndrome, was found more frequently among patients with PAPS (10.5%, 10.5% and 22.2% in MG, SLE and PAPS, respectively) than the idiotype H3, which was derived from a human hybridoma monoclonal aCL generated from a healthy subject immunized with tetanus and diphtheria. The latter idiotype was detected in 8.7%, 6.5% and 11.7% of patients with MG, SLE and PAPS, respectively. Incidental findings in this study include a high prevalence of aCL among patients with MG (23%) and a high prevalence of anti-dsDNA antibodies, detected only by a sensitive enzyme-linked immunosorbent assay, among patients with PAPS. Our results indicate that idiotypic diversity exists among aCL derived from different sources. Some of these cross-reactive idiotypes may be more pathogenic than others.

Adult↗
PubMed1992

Timing between the subcutaneous administration of insulin and consumption of a carbohydrate rich meal.

There is considerable uncertainty as to the appropriate timing of preprandial injections of short acting insulin before consumption of a meal. 8 healthy male volunteers were subjected to a glucose clamp (glucose 4.2 mmol/l) by means of a continuous insulin infusion on two occasions. On each occasion the subjects ingested a standardized meal. Twelve units of short acting insulin were injected subcutaneously either immediately before (A) or 30 min prior to the meal (B). In a control study (C) only the meal was consumed. The maximal increment of insulin concentrations after sc injection was 53.1 (6.9) mU/l in A and 58.6 (5.1) mU/l in B and thus comparable to C (52.8 (4.7) mU/l), however it was reached 30 to 60 min later as compared to endogenous stimulation. Injection 30 min prior to meal resulted in higher insulin concentrations early after the meal, but the glucose infusion rate doubled to 5.3 (0.3) mg/kg/min before the meal in order to prevent hypoglycaemia. Omission of this time interval is less hazardous, but bears the risk of late postprandial hyperinsulinaemia.

Adult↗
PubMed1991

The H3 anti-phospholipid idiotype is found in patients with systemic lupus erythematosus (SLE) but not in patients with syphilis.

The human H3 idiotype, defined by a mouse monoclonal antibody S2.9, is commonly found in patients with SLE where it is correlated with the amount of anti-cardiolipin antibodies. No correlation between the amount of anti-cardiolipin antibody and the H3 idiotype is found in patients with syphilis. Using the S2.9 antibody, serum from each of 10 patients with SLE and eight patients with syphilis was separated into H3-bearing and H3-negative fractions. Comparison of the partition of anti-cardiolipin antibody in these two groups of patients revealed that much of the anti-cardiolipin antibody (44-91%) was found in the H3+ fraction in patients with SLE; in patients with syphilis, virtually none of the anti-cardiolipin antibody was H3+. In patients with SLE, the H3+ fraction contained both IgG and IgM and antibodies of both kappa and lambda light chains. The H3+ fraction was polyspecific and frequently reacted with dsDNA.

Antibody Specificity↗
PubMed1991

Impaired balance of interleukin-4 and interferon-gamma production in infections with Schistosoma mansoni and intestinal nematodes.

In chronic infection with Schistosoma mansoni, IL-4 and IFN-gamma are co-modulated in opposite directions. This was shown when testing sera and cell culture supernatants from 31 Brazilian patients with schistosomiasis before, and three months after treatment with praziquantel. Thorough examinations were undertaken to account for polyparasitism with intestinal nematode infections involving tissue migrating larval stages that may induce analogous changes. Controls free of S. mansoni included a group (n = 17) matching the schistosomiasis patients' parasitation by intestinal nematodes and a group (n = 16) free of helminths other than T. trichiura. Serum IL-4 was greater than 20 pg/ml in 81% of schistosomiasis patients but in only 35 and 25%, respectively, of controls with and without intestinal nematodes. IL-4 data correlated inversely with the mitogen-induced IFN-gamma synthesis. Generation of IL-4 in response to phorbol esters was related to the intensity of infection by schistosomes and intestinal nematodes. The parasitological status three months after therapy with either praziquantel or mebendazole revealed a dichotomy: whereas the ratio of IFN-gamma to IL-4 generated in vitro was identical in uninfected controls and in patients who cleared the parasites, failure to eliminate the parasites was associated with lower IFN-gamma/IL-4 ratios generated in vitro.

Female↗
PubMed1989

[Action profile of human ultralente insulin compared with human NPH-insulin].

The effect of human NPH insulin (Protaphan HM) and of human ultralente insulin (Ultratard HM) on the profile of blood-glucose concentration was compared, using the glucose clamp technique, in normal subjects after subcutaneous injection of 12 U each. After Protaphan, insulin concentration rose by 11.0 +/- 1.6 microU/ml; maximal glucose infusion rate (GIR) after five hours was 4.7 +/- 0.5 mg/kg.min. But after the same dosage of Ultratard, insulin concentration rose by only 4.7 +/- 1.0 microU/ml (P less than 0.02) on a maximal GIR after ten hours of 3.2 +/- 0.5 mg/kg.min (no significant difference). Ultratard had up to 70% of the maximal Protaphan effect, the infused amount of glucose, up to maximal effect at 9.5 h (72 +/- 9 g), being significantly lower (P less than 0.02) than after Protaphan (130 +/- 18 g). After, respectively, 16 (Protaphan) and 20 (Ultratard) hours, basal insulin levels were again reached. GIR 19 h after Protaphan injection was 1.3 +/- 0.4 mg/kg.min, while 24 h after Ultratard it was 1.5 +/- 0.2 mg/kg.min, which was not significantly different from the basal rate. The difference between Protaphan and Ultratard lies in the marked initial effect of NPH insulin, up to 10 h after injection. In the later phase of the effect profile both insulins were similar at the chosen dose of 12 U.

Adult↗
PubMed1989

Microplate ELISA for detection of antibodies to DNA in patients with systemic lupus erythematosus: specificity and correlation with Farr radioimmunoassay.

A 96-well microplate ELISA for the detection of antibodies to DNA is described. A number of buffers and precoating treatments were used to evaluate the optimal method for coating the plate with DNA. These included pretreatment of the plates with poly-L-lysine or protamine sulfate, and posttreatment with glutaraldehyde, none of which improved the performance of the assay. Whereas bicarbonate and borate coating buffers gave equivalent and satisfactory results, TRIS buffer resulted in very high binding of immunoglobulin to wells not coated with antigen. Sera from groups of patients with autoimmune disease as well as normal sera were tested against plates optimally coated with native E. coli DNA, calf thymus DNA, and heat-denatured DNA. Using native E. coli DNA, virtually none of 35 normal sera had any detectable antibody. With this antigen, as well as with native calf thymus DNA, significant levels of DNA antibody were found only in SLE patients. Most patients with SLE or drug-induced lupus, as well as some patients with rheumatoid arthritis and normal individuals had antibodies that bound to heat-denatured (single-stranded) DNA. Using either native E. coli or calf thymus DNA, a good correlation was found between the amount of DNA antibody detected by ELISA and the Farr-type radioimmunoassay.

Autoantibodies↗
PubMed1989

Pulsatile insulin infusion and glucose-homeostasis in well-controlled type 1 (insulin-dependent) diabetic patients.

Pulsatile, intravenous insulin infusion designed to mimic the portal insulin concentrations that emerge physiologically after a meal, has been postulated to improve glucose tolerance in Type 1 (insulin-dependent) diabetic patients. We studied the effects of insulin pulsing (10 i.v. pulses of human insulin of 0.035 U kg-1 idealised body weight were given, each of 20 s duration, with intervals of 6 min, three times per day covered with adequate administration of glucose) on 2 successive days on glucose-tolerance in nine well-controlled Type 1 diabetic patients on continuous subcutaneous insulin infusion therapy (age 26 (7) years, mean (SD); duration of diabetes 10 (7) years; body mass index 23.4 (2.3) kg m-2; HbA1c 6.0 (0.6)%). On the days before and after the insulin pulsing, the patients were subjected to metabolic assessments by an oral glucose tolerance test (1 g glucose kg-1 body weight) 30 min after the subcutaneous injection of 0.15 U kg-1 body weight regular human insulin and a subsequent bicycle-ergometer test. During these metabolic assessments, plasma free insulin concentrations, plasma glucagon and the non-protein respiratory quotient remained unaffected by the insulin pulsing. However, glucose tolerance deteriorated significantly (maximal glucose concentration 120 min after glucose load was 10.0 mmol l-1 before and 13.9 mmol l-1 after insulin pulsing, P less than 0.01). In conclusion, the pattern of insulin pulsing used in this study did not ameliorate oral glucose homeostasis in well-controlled Type 1 (insulin dependent) diabetic patients.

Adult↗
PubMed1989

The action profiles of human NPH insulin preparations.

The complete time-action profiles of four subcutaneously injected human NPH insulin preparations (Protaphane HM/Novo; Insulatard Human/Nordisk; Huminsulin Basal/Eli Lilly; Basal H-Insulin/Hoechst) have been investigated by means of the euglycaemic clamp technique (blood glucose 5.0 mmol l-1). Six normal male subjects were connected to a Biostator on five occasions in randomized order including a control study without insulin injection. A stable basal insulin level of about 10 mU l-1 was established by means of a low dose insulin infusion (0.1 mU kg-1 min-1) which subsequently suppressed C-peptide by 35 +/- 19% (mean +/- SD) to levels of around 0.3 nmol l-1. Twelve units of NPH insulin were injected subcutaneously into the abdominal wall and glucose infusion rates were monitored for 19 h. In the control study, the mean glucose infusion rate was 1.11 +/- 0.60 (range 0.32-1.95) mg kg-1 min-1. Maximal glucose infusion rates, reached 5-7 h after injection, were comparable (4.3-4.9 mg kg-1 min-1) for the four different preparations used. Glucose infusion rates returned to basal rates within the 19 h study period. Mean plasma free insulin levels peaked at 17.5-18.6 mU l-1 3-4.5 h after injection and returned to basal levels within 16 h. The time ranges of greater than 90, greater than 75, greater than 50, and greater than 25% of maximal insulin action (as estimated from glucose infusion rates) revealed no significant differences between the four insulin preparations tested. No significant insulin action was observed beyond 17 h after insulin injection of any preparation.

Adult↗
PubMed1989

A common anti-cardiolipin antibody idiotype in autoimmune disease: identification using a mouse monoclonal antibody directed against a naturally-occurring anti-phospholipid antibody.

We have recently produced a series of human monoclonal antibodies reacting with cardiolipin. One of these, H3, a polyspecific IgM/k derived from a normal individual, was used to raise mouse monoclonal antibody to its idiotype. Two anti-idiotypic antibodies, S2.9 (IgG2b) and S2.10 (IgM) were selected for their specific reaction with H3.S2.9 did not react with five other human monoclonal antibodies of IgM/k class despite the fact that these shared some antigen-binding characteristics with H3.S2.9 was able to block the binding of H3 to all of its cross-reactive antigens including cardiolipin, while S2.10 was not. S2.9 was equally efficient in blocking the binding of H3 to three of its cross-reactive antigens, cardiolipin, diphtheria and tetanus toxoids; greater than 90% inhibition could be achieved at an equimolar ratio of H3 to S2.9. The anti-idiotype S2.9 was used to demonstrate the presence of the H3 idiotype in serum. This idiotype was found in amounts greater than that seen in 42 normal individuals, in 30 of 36 patients with systemic lupus erythematosus (SLE), eight of 20 patients with rheumatoid arthritis (RA), 8 of 20 patients with Felty's syndrome as well as 10 of 23 patients with syphilis. Not one of nine patients with drug-induced lupus syndrome had abnormal levels. In patients with SLE and Felty's syndrome there was a good correlation between the amount of anti-cardiolipin antibodies and the amount of H3 idiotype (rs = 0.70 and 0.69 respectively). No such correlation was found in syphilitics or in patients with RA. In patients with SLE the H3 idiotype was present on IgM and IgG anti-cardiolipin antibodies. In 15 of 16 SLE sera with high levels of cardiolipin antibody, S2.9 blocked binding of serum antibodies to cardiolipin by 13-72%, with a mean value of 49%. One patient had a high level of anti-cardiolipin antibody which could not be blocked by S2.9. These results indicate that a mouse monoclonal antibody which reacts with an idiotope in the antigen-binding region of a naturally-occurring phospholipid antibody also defines a common idiotype of anti-cardiolipin antibodies in patients with autoimmune disease.

Antibodies, Anti-Idiotypic↗
PubMed1988

Monoclonal alkaline phosphatase-anti-alkaline phosphatase (APAAP) complex: production of antibody, optimization of activity, and use in immunostaining.

A mouse monoclonal antibody, FMC55 (an IgG1), to alkaline phosphatase was prepared and evaluated in immunostaining. Clones producing antibody to alkaline phosphatase were selected using a micro-ELISA which identified antibodies forming active soluble complexes (APAAP) with the enzyme. Conditions that influenced the formation of the complex were investigated by using a quantitative assay in which the complex was captured by a bridging anti-mouse antibody. The ratio of FMC55 to enzyme had a major influence on the activity of the complex. Although all complexes had some activity, those that contained excess antibody had reduced ability to bind to anti-mouse antibody because of competition with excess unlabeled antibody. The optimal complex was formed with 3 micrograms of FMC55 per unit of enzyme. This complex contained neither free enzyme nor free antibody. The molecular weight by gel permeation chromatography was 600,000, giving a composition of two enzyme and two antibody molecules or one enzyme and three antibody molecules. The size of the complex was not altered by adding excess antibody or excess enzyme. Immunoblotting showed that FMC55 bound only to the Mr 140,000 homodimeric form of alkaline phosphatase. The APAAP complex was used in combination with biotin-streptavidin-peroxidase reagent to detect two antigens labeled with two different mouse monoclonal antibodies in the same tissue preparation.

Alkaline Phosphatase↗
PubMed1988

Polyspecific human and murine antibodies to diphtheria and tetanus toxoids and phospholipids.

Human-human hybridomas produced from lymphocytes of normal individuals yielded seven clones producing monoclonal antibody reacting with tetanus toxoid. Three of these antibodies cross-reacted with diphtheria toxoid. These three and two others also reacted with cardiolipin and two with other phospholipids. One of the seven antibodies reacted with tetanus and diphtheria toxoids, cardiolipin and single-stranded DNA. All seven antibodies were IgM. To examine further this unusual cross-reactivity serum antibodies from patients with SLE and healthy individuals were affinity-purified to yield diphtheria toxoid antibodies. Six out of nine of these anti-diphtheria preparations contained IgG antibodies which cross-reacted with tetanus toxoid and two of these also reacted with cardiolipin; four preparations cross-reacted with DNA. Anti-cardiolipin and anti-DNA cross-reactivity were found in preparations from both normal and SLE sera. Similar cross-reactivities were demonstrated using four mouse monoclonal IgM antibodies raised against phospholipids. All four of these antibodies reacted with both cardiolipin and tetanus toxoid and two also reacted with diphtheria toxoid and DNA. Using a thiocyanate elution procedure, it was shown that the cross-reactivity of the monoclonal antibodies was not related to their relative affinities. The results clearly indicate that cross-reactive epitopes occur on routinely used toxoid vaccines and self antigens. Antibodies which bind to these cross-reactive epitopes are common and are not restricted in isotype, affinity or species of origin.

Animals↗
PubMed1985

The human leucocyte P30 antigen: properties and assessment of value as a clonal marker.

FMC3 and FMC29 are monoclonal antibodies which react with a 30,000 Dalton molecule expressed on the lymphocyte surface membrane. The molecule is a protein which does not appear to be N-glycosylated. The antigen, which is also expressed intracellularly, does not appear to be a marker of differentiation or maturation. Polyclonal cell populations, such as peripheral blood lymphocytes, show a bimodal distribution of surface antigen density, whilst monoclonal cell populations analysed quantitatively showed unimodal antigen density distributions. This suggests the antigen may be a clonal marker.

Antibodies, Monoclonal↗
PubMed1979

Intestinal and serum antibody responses in mice after oral immunization with Salmonella, Escherichia coli, and Salmonella-Escherichia coli hybrid strains.

After oral feeding of mice with avirulent Salmonella, Escherichia coli, or hybrid strains, only certain bacterial strains were able to multiply and persist within the small intestinal Peyer's patches. After oral vaccination alone, or oral priming and subsequent parenteral boosting, antibody class and titers were detected, using a radioimmunoassay on serum and intestinal fluid or a plaque-forming cell assay on spleens. Only those strains that persisted in the Peyer's patches stimulated the production of serum and intestinal immunoglobulin A antibodies against their respective O antigens. Nonpersistent strains were weakly immunogenic, and antibodies, when present, were largely non-immunoglobulin A and confined to the serum.

Animals↗
PubMed1978

McCollough effect and eye optics.

Astigmatism induced by cylindrical lenses leads to colour sensations similar to the McCollough effect. Consequences for the design of experiments and a new interpretation of the McCollough effect are suggested.

Accommodation, Ocular↗