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Biomedical subjects

C Heilmann

Publications and source records attributed to C Heilmann.

At least 109 records · Page 6Linked to original sources

Ca2+-activated ATPase in microsomes from human liver.

Human liver microsomal fractions exhibit ATP-supported Ca2+ uptake which is half-maximal at 7 X 10(-7) M free Ca2+ in the presence of oxalate. Ca2+ uptake is coupled to a Ca2+-stimulated ATPase activity, which is half-maximal at 4 X 10(-7) M free Ca2+. Catalysis involves formation of an Mr = 116,000 phosphoprotein with stability characteristics of an acylphosphate compound suggested to represent a phosphoryl protein intermediate of the Ca2+-ATPase. Phosphorylation is half-maximal at about 10(-6) M free Ca2+. The Mr = 116,000 protein is highly susceptible to proteolysis with trypsin. The phosphorylated active site was localized in an Mr = 58,000 primary tryptic fragment and in an Mr = 34,000 subfragment. Analyses on the mechanism of the Ca2+-ATPase suggest the following reaction sequence: formation of an ADP-reactive phosphoenzyme (Mr = 116,000) with bound Ca2+, which can transphosphorylate its Pi to ADP, giving rise to synthesis of ATP; reversible transformation of the ADP-reactive phosphoenzyme into an isomer without bound Ca2+, which cannot further react with ADP; hydrolytical cleavage, probably catalyzed by Mg2+, of the ADP-unreactive phosphoenzyme with liberation of Pi. Comparison with the Ca2+-transport ATPase in sarcoplasmic reticulum of skeletal muscle led us to suggest that the Mr = 116,000 Ca2+-ATPase belongs to the class of E1P . E2P-ATPases and might be operative as a Ca2+-transport ATPase at the level of the endoplasmic reticulum in human liver.

Calcium↗

Complement C3b receptors on erythrocytes in patients with juvenile rheumatoid arthritis.

Forty patients with juvenile rheumatoid arthritis (JRA) were examined for C3b receptor (CR1) levels on erythrocytes (by an enzyme-linked immunosorbent assay), levels of circulating immune complexes (IC) (by a polyethylene glycol precipitation-complement consumption method), C3d split products (by intermediate gel rocket immunoelectrophoresis), and HLA-A, B, and C (by microdroplet lymphocytotoxicity test). Lower CR1 levels were found predominantly among patients with JRA (mean 57%) compared with 40 age-matched controls (mean 68%) (P = 0.008). The CR1 levels differed when the JRA patients were grouped by mode of disease onset and by clinical state at the time of testing (levels in patients with pauciarticular disease were higher than those in patients with polyarticular disease, and levels in patients with polyarticular disease were higher than those in patients with systemic disease) or by sex (girls had higher levels than boys; P = 0.01). The levels of circulating IC and C3d were elevated in 25% and 40% of JRA patients, respectively, and were mutually correlated (P less than 0.05, tau = 0.20). A negative correlation was found between levels of C3d and the numbers of CR1 (P less than 0.01, tau = -0.28), but concentrations of circulating IC did not correlate with CR1 values. CR1 levels were the same in 6 HLA-B27 positive and 25 HLA-B27 negative patients. These findings do not represent conclusive evidence that the number of CR1 on erythrocytes serves as a predictor of disease severity or as an indicator of disease activity in patients with JRA.

Adolescent↗

Adrenocortical insufficiency associated with Epstein-Barr virus infection in a patient with the Wiskott-Aldrich syndrome.

A 10-year-old boy with the Wiskott-Aldrich syndrome developed adrenocortical insufficiency including typical clinical findings, low s-Na, high s-K, high p-ACTH (640 ng/l), low p-aldosterone (33-39 pmol/l), high p-renin (2300-4200 mIU/l) as well as an abnormal response to an ACTH-stimulation test. The adrenocortical insufficiency developed concomitantly with the occurrence of infectious mononucleosis diagnosed clinically and serologically. Adrenalitis caused by Epstein-Barr virus is suggested as the causative factor.

Adolescent↗

Colistin inhalation therapy in cystic fibrosis patients with chronic Pseudomonas aeruginosa lung infection.

Forty patients with cystic fibrosis and chronic broncho-pulmonary Pseudomonas aeruginosa infection entered a prospective double-blind placebo-controlled study of colistin inhalation. Active treatment consisted of inhalation of colistin one million units twice daily for three months and was compared to placebo inhalations of isotonic saline. Significantly more patients in the colistin inhalation group completed the study as compared to the placebo group (18 versus 11). Colistin treatment was superior to placebo treatment in terms of a significantly better clinical symptom score, maintenance of pulmonary function and inflammatory parameters. We recommend colistin inhalation therapy for cystic fibrosis patients with chronic P. aeruginosa lung infection as a supplementary treatment to frequent courses of intravenous anti-pseudomonas chemotherapy.

Administration, Inhalation↗

Vaccination-induced circulation of human B cells secreting type-specific antibodies against pneumococcal polysaccharides.

Indirect plaque-forming cell assays detecting B cells secreting antibodies against capsular pneumococcal polysaccharide (PPS) antigens are described. In healthy adult volunteers the total number of B cells secreting IgM antibodies against the antigens in a polyvalent PPS vaccine reached a maximum in the blood 6 days after in vivo immunization (mean: 552/10(6) mononuclear cells), whereas the highest concentration of IgG and IgA antibody-secreting cells (SC) were detected 7 days after immunization (means: 628 and 1691/10(6]. B cells secreting antibodies to PPS type 3 (PPS3), PPS8, PPS18C and C-polysaccharide (CPS)--a cell wall antigen common to all pneumococci--constituted 9%, 16%, 6% and 5% (means) of the total number of antibody SC respectively. While the majority of the anti-PPS-SC secreted IgA antibodies, the anti-CPS-SC almost exclusively secreted IgG. Pre-vaccination concentrations of anti-PPS were generally low in contrast to antibodies against CPS, which were present in high concentrations in all individuals. The discrepancy in the Ig class of the antibody SC is probably related to the difference in the pre-vaccination immunity against PPS and CPS.

Adult↗

Pancreatic enzyme supplementation as acid-resistant microspheres versus enteric-coated granules in cystic fibrosis. A double placebo-controlled cross-over study.

In order to compare the efficacy of pancreatic enzyme supplementation as pH-sensitive enteric-coated microspheres Pancrease to that of conventional supplementation with enteric-coated Pancreatin in cystic fibrosis, a double blind cross-over study was conducted. Eleven patients under 12 years of age received each of the enzyme preparations for four weeks. Treatment efficacy was evaluated by means of a symptom score card recording stool frequency, consistency, colour, odour, abdominal cramps and appetite as well as a 3 days fat absorption test. Weight increments were recorded 3 months before the study when patients were on Pancreatin, and 3 months after the study when patients were on Pancrease. In eight of the patients fat absorption was improved on Pancrease, but the difference did not reach statistical significance. However, the patients experienced significantly less dyspeptic symptoms, decreased stool frequency, better appetite and increments in weight were significantly higher on Pancrease compared to Pancreatin.

Child↗

Vaccination-induced activation of human blood T cells suppressing pneumococcal polysaccharide-specific B cells.

In order to study the regulation of the human B cell response to pneumococcal polysaccharides (PPS), anti-PPS-secreting cells (SC) and Ig-SC were quantitated in unstimulated and EBV-stimulated cultures of blood mononuclear cells (MNC) established before and one and two weeks after vaccination. In unstimulated cultures established one week after vaccination, significant numbers of anti-PPS-SC were detected; however, they were observed only in cultures depleted of T cells (mean: 62/10(6)), suggesting the presence of T cells suppressing in vivo-activated PPS-specific B cells. In EBV-stimulated cultures depleted of T cells, low numbers of anti-PPS-SC were observed before the vaccination, and the numbers of these cells increased significantly two weeks after the immunization (from 28 to 48/10(6)). In contrast, the numbers of anti-PPS-SC and total Ig-SC decreased in EBV-stimulated cultures of unseparated MNC established after the vaccination, suggesting T cell-mediated suppression. The findings were not explained by changes in the numbers of blood T helper (Leu 3+) or T suppressor (Leu 2+) cells following the vaccination. Possibly the vaccination induces the appearance in the blood of activated suppressor cells responsible for the suppression of B cells in unstimulated and EBV-stimulated cultures.

Adult↗

Function of pokeweed mitogen-stimulated human T cells following vaccination with pneumococcal polysaccharides.

The T cell regulation of pneumococcal polysaccharide (PPS)-specific B cells was investigated in pokeweed-mitogen (PWM)-stimulated cultures. The numbers of anti-PPS-secreting cells (SC) increased in cultures of mononuclear cells (MNC) established two weeks after the vaccination, as compared to cultures established before vaccination (from 18/10(6) MNC to 45/10(6) MNC). This finding was most likely explained by an increase in the blood of B-cell precursors with specificity for PPS. B cells spontaneously secreting anti-PPS were found only in cultures established one week after vaccination. However, the presence of PWM and T cells increased the numbers of anti-PPS-SC also in these cultures, indicating that not all PPS-specific B cells are fully differentiated in vivo one week after vaccination. The vaccination-induced changes in T cell function were investigated by recombining cryopreserved T cells or T helper cells (CD8 negative cells) with freshly isolated autologous B cells from post-vaccination day 15. The numbers of total Ig-SC in cultures containing day 13 T cells were significantly lower than the numbers in cultures containing day 0 T cells (3958/10(6) MNC versus 5887/10(6) MNC). The same tendency was observed for anti-PPS-SC; this difference, however, was not significant. No differences were observed in the ability of T helper cells to support the generation of total Ig-SC and anti-PPS-SC. Irradiation (2300 rad) of T cells from day 0 increased the numbers of anti-PPS-SC in the cultures significantly (three times), whereas irradiation of day 15 T cells did not have a significant augmenting effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Increased prevalence of late stage T cell activation antigen (VLA-1) in active juvenile chronic arthritis.

The presence of activated T cells as judged from the reaction with monoclonal antibodies (MoAb) against (a) a late stage T cell activation antigen (VLA-1), (b) the interleukin 2 (IL2) receptor (CD25), and (c) four different HLA class II molecules (HLA-DR, DRw52, DQ, and DP) was studied in 15 patients with active juvenile chronic arthritis (JCA), 10 patients with JCA in remission, and 11 age matched, healthy controls. In addition, the distribution of T 'helper/inducer' (CD4+), T 'suppressor/inducer' (CD4+, Leu8+), T 'suppressor/cytotoxic' (CD8+), and 'natural killer' (NK) cells (CD16+) was studied. Twenty patients and six controls were investigated for the capability to stimulate alloreactivated primed lymphocytes. The prevalence of VLA-1 positive, large cells was significantly increased to 5% (median value) in active JCA as compared with JCA in remission (2%, p less than 0.05) and controls (1%, p less than 0.05), whereas no significant difference between JCA in remission and controls was observed. Except for two patients with active JCA, less than 1% IL2 receptor bearing cells were found in patients with JCA and controls. No significant difference in the prevalence and expression of the various HLA class II antigens was observed between the groups. Similarly, no significant differences in stimulatory capability in secondary mixed lymphocyte culture (MLC) were seen. The distribution of T helper/inducer (CD4+), T suppressor/cytotoxic (CD8+), and NK cells was similar in active JCA, JCA in remission, and controls. The prevalence of T suppressor/inducer (CD4+,Leu8+) cells was higher in remission JCA (17%) than in active JCA (11%) and controls (10%). This increase, however, did not reach statistical significance. In conclusion, late stage but not early stage T cell activation antigens were increased in patients with active JCA as compared with patients with JCA in remission and control, whereas some patients in remission had an increased prevalence of T suppressor/inducer cells.

Adolescent↗

Pokeweed mitogen-induced secretion of IgG- and IgM-rheumatoid factors by synovial fluid and blood B lymphocytes in rheumatoid arthritis.

Lymphocytes from patients with rheumatoid arthritis (RA) were assayed for their ability to secrete Ig and rheumatoid factors (RF) upon polyclonal activation in vitro. B lymphocytes secreting IgM-RF and IgG-RF were enumerated using hemolytic plaque forming cell (PFC) assays. The sensitivity of RF-PFC formation was similar to that of a reverse PFC assay detecting all cells secreting Ig. Blood mononuclear cells from RA patients generated a median of 12 IgM-RF and 15 IgG-RF-secreting cells/10(6) after 6 days culture with pokeweed mitogen (PWM). Thus a median of approximately 0.5% of IgM- and IgG-secreting cells were identified as RF-PFC. Synovial fluid B lymphocytes co-cultured with autologous blood T lymphocytes in the presence of PWM generated higher numbers of RF-secreting cells; medians of 43 IgM-RF and 441 IgG-RF secreting cells/10(6) were found. Thus, 8-9% of IgM- and IgG-secreting cells from synovial fluid were identified as RF-PFC. In co-cultures containing synovial fluid T cells, PWM-induced RF secretion was low. The data indicate that both blood and SF B cells have the potential for RF secretion.

Antibody Formation↗

Quantitation of blood lymphocytes secreting antibodies to pneumococcal polysaccharides after in vivo antigenic stimulation.

An indirect plaque-forming cell assay detecting B cells secreting IgM, IgG and IgA antibodies against pneumococcal polysaccharides (PPS) is described. The numbers of anti-PPS-secreting cells (SC) and Ig-SC in the blood of normal persons immunized with a polyvalent PPS vaccine were quantitated. Anti-PPS-SC were recorded from the fourth to the twelfth post-vaccination day, and the maximum number was found between days 6 and 9. Quantitatively IgA anti-PPS-SC outnumbered the IgM and IgG anti-PPS-SC. Concomitant with the increase in the numbers of antibody-SC an increase in polyclonally activated IgM-, IgG- and IgA-SC was recorded. The specific anti-PPS-antibody-SC constituted 20-80% of the total numbers of Ig-SC from the sixth to the ninth post-vaccination day.

Animals↗

Increased frequency of HLA-DPw2 in pauciarticular onset juvenile chronic arthritis.

Thirty-six unrelated Danish patients with pauciarticular Juvenile Chronic Arthritis (PJCA) and 120 controls were typed for HLA-DPw1-w6 and the local specificity CDPHEI with bulk-expanded Primed Lymphocyte Typing (PLT) cells. The frequency of HLA-DPw2 was 52.8% in PJCA patients and 16.7% in controls (relative risk, RR = 4.5; P less than 0.001). The antigens HLA-Dw5 and/or Dw8 were present in 50% of the patients and in 21.3% of the controls (RR = 4.2; p less than 10(-3)). DPw2 was not associated (in linkage disequilibrium) with Dw5/w8 in patients or in controls, and the DP and D associations with PJCA were independent of each other. However, the combined presence of DPw2 and Dw5 and/or Dw8 gave a significantly higher risk of PJCA than each antigen alone indicating interaction of DP and DR gene products. PJCA is the first disease definitely found to be associated with a DP antigen.

Arthritis, Juvenile↗

Reaction mechanism of the calcium-transport ATPase in endoplasmic reticulum of rat liver. Demonstration of different reactive forms of the phosphorylated intermediate.

A calcium-transport ATPase is inserted into the endoplasmic reticulum of rat liver. Catalysis of calcium translocation involves transient covalent binding of the terminal phosphate residue of ATP by the enzyme, resulting in the formation of an alkali- and hydroxylamine-labile phosphorylprotein intermediate. Both MgATP as well as CaATP can be utilized in the phosphorylation reaction which requires calcium as a cofactor. Magnesium accelerates the turnover of the phosphorylprotein intermediate. An ADP-reactive and ADP-unreactive state of the phosphoenzyme could be distinguished. In the ADP-reactive state with tightly bound calcium, the phosphoenzyme can transphosphorylate its phosphate residue to ADP, giving rise to synthesis of ATP. The ADP-reactive phosphoenzyme can be converted into an ADP-unreactive state by prolonged incubation with excess EGTA (ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid). It is suggested that this conversion is brought about by the removal of tightly bound calcium from the phosphoenzyme. A strong homology of the sequential reaction steps during calcium translocation by the calcium-transport ATPases in endoplasmic reticulum from rat liver and sarcoplasmic reticulum from skeletal muscle is suggested.

Adenosine Diphosphate↗

HLA antigen frequencies in juvenile chronic arthritis.

HLA-A, B, C, D, and DR typing was performed in 104 patients with Juvenile Chronic Arthritis (JCA). The majority of these (88 patients) participated in a follow-up study of a series of consecutive patients including patients in remission. The study confirmed that JCA is positively associated with B27, Dw8, and possibly Dw5, and negatively associated with Dw2 and Dw7. In JCA patients in remission, the frequency of Dw4 was significantly decreased to 5.0%, compared with 25.0% in healthy Danes and 23.7% in JCA patients with active disease. In pauciarticular onset JCA, the frequency of Dw4 was significantly decreased to 8.1% compared with 25.0% both in controls and in polyarticular onset JCA. These data indicate that Dw4 may be a risk factor of chronicity and multiple joint involvement in JCA. Chronic iritis was present in 18.2% of Dw8-positive patients, compared with 7.0% in Dw8-negative patients, and the frequency of Dw8 was 50.0% in JCA patients with chronic iritis. Thus, Dw8 may be a risk factor of chronic iritis in JCA. Genetically, three distinct subgroups seem to exist: (i) a B27-associated group; (ii) a D/DR5- and D/DRw8-associated group, and (iii) a D/DR4-associated group.

Adolescent↗

HLA-B27 in juvenile chronic arthritis.

The prevalence of HLA-B27 in 88 patients with juvenile chronic arthritis was 22/88 (25%) with little variation among the 3 commonly recognized onset types. This was significantly more frequent than the prevalence of 9.4% in a Danish reference population. A strong association was found between the HLA-B27 antigen and 3 subgroups of patients: (1) boys with pauciarticular and late onset disease; (2) girls with apophyseal joint fusion; (3) a group of patients in whom the clinical picture was compatible with reactive arthritis or incomplete Reiter's syndrome. When these 3 subgroups were excluded from the total patient population, only 8 of the remaining 63 patients carried the B27 antigen, i.e., 13%, which was not significantly different from the prevalence in the reference population. Thus, the 3 subgroups account completely for the increase of B27 in the entire group of patients.

Adolescent↗

The calcium pump in rat liver endoplasmic reticulum. Demonstration of the phosphorylated intermediate.

Rat liver microsomal fractions enriched with smooth-surfaced vesicles possess an ATP-supported Ca2+ transport activity, which is stimulated by oxalate and half-maximally activated at 3.5 X 10(-7) M free Ca2+. Catalysis of Ca2+ transport involves transient covalent binding of the terminal phosphate from ATP by the vesicles, resulting in the formation of a Mr 118,000 phosphopeptide, which is acid precipitable and unstable in the presence of hydroxylamine, which may be characteristic for an acylphosphate. Phosphorylation of the Mr 118,000 peptide requires the presence of Ca2+, while dephosphorylation is markedly accelerated by Mg2+. In the presence of Ca2+ and Mg2+ phosphorylation proceeds much faster than dephosphorylation, indicating that the latter may be rate limiting for the hydrolysis of ATP. The Mr 118,000 peptide is estimated to represent about 2% of total smooth-surfaced endoplasmic reticulum membrane protein. Comparative studies with sarcoplasmic reticulum from rat skeletal muscle suggest extensive homology of the Ca2+ transport ATPases.

Animals↗