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Biomedical subjects

F Bachmann

Publications and source records attributed to F Bachmann.

At least 37 records · Page 2Linked to original sources
PubMed1990

Detection of Epstein-Barr virus DNA by polymerase chain reaction in lymph node biopsies from patients with angioimmunoblastic lymphadenopathy.

Epstein-Barr virus DNA was detected by the polymerase chain reaction (PCR) in five lymph node biopsies from eight patients with diagnosis of angioimmunoblastic lymphadenopathy (AILD). Three pairs of specific primers detected EBV DNA sequences near the 5' end (Bam W region), the middle (BMRF 1 region) and the 3' end (Eco RI D region) of the viral genome with equal accuracy when 1 microgram of DNA and 30 amplification cycles were used. When only 100 ng of DNA were screened with the BMRF 1 set of primers, a specific amplification product was still identifiable. The 593 base pair amplification product obtained using the Eco RI D set of primers was shown to contain an expected Sma I site at position 215, confirming the viral origin of the amplified sequence [corrected]. Our findings indicate that lymph nodes of AILD patients frequently harbour the entire EBV genome at a high percentage of at least 1 viral copy per 15,000 human cells.

Base Sequence↗
PubMed1990

Antigen levels of plasminogen activator inhibitor type 1 in citrated plasma: determination of the contribution of platelets.

To estimate the extent of the release of plasminogen activator inhibitor type 1 (PAI-1) from platelets following their accidental activation in vitro during blood collection, we studied the antigen levels of PAI-1 and beta-thromboglobulin (beta TG) in plasma and sera from 38 healthy volunteers. For each volunteer, we calculated the ratio of platelet-derived PAI-1/platelet-derived beta TG from the difference in their respective concentrations in serum and plasma. The mean +/- SD (0.012 +/- 0.003) and median (0.012) ratios were identical before and after 10 or 20 min of venous occlusion. The platelet contribution of PAI-1 in plasma was estimated by multiplying the plasma concentration of beta TG (as a marker of platelet activation) with the above-mentioned individual ratio. Under our conditions of blood collection (1/10 vol of 0.1 M citrate, pH 4.5, as anticoagulant, and handling of blood at 4 degrees C and within 30 min), the platelet contribution to the PAI-1 concentration in plasma was on average 12% and always negligible in plasma with high levels of PAI-1.

Adult↗
PubMed1990

[Phenotypic and genotypic characterization of splenic infiltrates in hairy cell leukemia].

Cells of splenic infiltrates of five patients with hairy cell leukemia have been analyzed for the expression of immunoglobulin by immunohistochemistry and for rearrangement of T cell receptor and immunoglobulin genes by the Southern blot technique. In each case surface immunoglobulins were found with monoclonal expression of light chains. Concomitantly, heavy and light chain gene rearrangements were present. These results confirm the B cell nature of hairy cells.

Blotting, Southern↗
PubMed1989

[Hairy cell leukemia: study of genomic rearrangements in splenic infiltration].

Genomic DNA extracted from heavily infiltrated spleens of 5 patients with hairy cell leukaemia was hybridized with genomic probes for immunoglobulin genes. The rearrangement pattern, correlating well with the immunohistochemical findings, was that of a clonal B-cell proliferation in all cases. Analysis of the lambda light chain genome with two different probes enabled more accurate localization of the clonal rearrangements within this genome. A small additional T-cell population identified in 3 cases was immunogenotypic of polyclonal (reactive) nature.

DNA Probes↗
PubMed1989

Plasminogen activators and plasminogen activator inhibitors in liver deficiencies caused by chronic alcoholism or infectious hepatitis.

Plasma concentrations of tissue-type plasminogen activator (t-PA), urokinase (u-PA), plasminogen activator inhibitor 1 (PAI-1) and PAI-2 were studied in 53 patients with liver deficiency caused by chronic alcoholism (n = 40), viral hepatitis (n = 10) or malignant disease of the liver (n = 3) and compared to that of a control group (n = 20) of healthy subjects. u-PA and PAI-1 levels were significantly increased in all patients with chronic alcoholism, whereas high t-PA was only observed in combination with disturbed liver function tests or with liver cirrhosis (two and six-fold above control values, respectively). A good correlation was observed between t-PA and gamma glutamyl transferase (r = 0.615; p less than 0.001). In patients with infectious hepatitis or with malignant disease of the liver t-PA was normal whereas u-PA and PAI-1 were increased. PAI-2 levels were close to or below the detection limit (15 ng/ml) in the control group and in most patients. However, in two patients with alcohol induced cirrhosis PAI-2 levels were approximately 45 ng/ml and in one patient with hepatocarcinoma even 66 ng/ml. Thus, in liver disease, marked elevations of t-PA, u-PA and PAI-1 levels may occur, with increased PAI-1 as an early marker of liver defects and t-PA a marker of severe liver defects.

Female↗
PubMed1989

Low molecular weight heparin Novo (LHN-1) does not cross the placenta during the second trimester of pregnancy.

Unfractionated heparin (UF-H) has been the drug of choice for the treatment of thromboembolic disorders during pregnancy. Low molecular weight heparin (LMW-H) preparations may present some advantages over UF-H. They have longer half-lives and a better bioavailability after subcutaneous (s. c.) injection and may cause less bleeding. It has not yet been established whether LMW-H Novo (LHN-1) crosses the placenta. 17 women admitted for abortion during the second trimester of pregnancy (induced by application of prostaglandine PGE2 gel at a concentration of 0.25 mg/ml into the cervix) were given s. c. 35 anti-Xa units per kg of body weight of LHN-1 (Novo). 10 patients not receiving LHN-1 and their fetuses served as a control group. 7 women in whom the time interval between injection of LHN-1 and expulsion of the fetus was less than 3 h or more than 7 h were excluded from further study. In one fetus blood collection failed. Anti-Xa and anti-IIa levels increased approximately ten-fold in women receiving LHN-1 [anti-Xa units/ml from 0.02 +/- 0.01 (mean +/- SD) to 0.17 +/- 0.01, p less than 0.001; anti-Ha units/ml from less than 0.01 +/- 0.01 to 0.07 +/- 0.03], but remained below the detection limit in their fetuses as well as in the women and fetuses of the control group. We conclude that LHN-1 at these doses does not cross the placenta during the second trimester of pregnancy to suggest that LHN-1 may be a safe alternative to heparin in the management of the thromboembolic complications during pregnancy.

Abortion, Induced↗
PubMed1989

Polyclonal rearrangements of the T-cell receptor beta-chain in fatal angioimmunoblastic lymphadenopathy.

Genomic rearrangement of germline T-cell antigen receptor (TcR) and immunoglobulin (Ig) genes was studied by Southern blot analysis in seven patients with angioimmunoblastic lymphadenopathy (AILD). In three cases clinically suspected of transformation into malignant lymphoma, hybridization with the TcR beta probe showed markedly dimished intensity in the 11.5 kb germline band after Eco RI digestion and normal germline configuration after Hind III and Bam HI digestion, indicating polyclonal T cell rearrangements. A clonal rearrangement of the TcR beta gene was detected in only one case at initial biopsy. No monoclonal rearrangement of Ig genes was observed. These data show that in some cases of AILD disease progression is indicated by polyclonal TcR rearrangements and not by outgrowth of a malignant clone, supporting the concept of AILD as an immunoregulatory disorder.

Blotting, Southern↗
PubMed1989

Plasminogen activators in dextran sulfate-activated euglobulin fractions: a molecular analysis of factor XII- and prekallikrein-dependent fibrinolysis.

To elucidate the mechanism by which activation of the contact system of blood coagulation leads to expression of fibrinolytic activity, we have determined the molecular characteristics of the plasminogen activators present in dextran sulfate-treated euglobulin fractions by electrophoretic-zymographic analysis and specific immunoadsorption. In addition to free and protease inhibitor-bound tissue-type plasminogen activator (t-PA), dextran sulfate precipitates of euglobulins contained the complex formed between plasma kallikrein and C1-inhibitor, an indicator of prekallikrein activation. These precipitates also contained substantial fibrinolytic activity related to urinary-type plasminogen activator (u-PA). Autoradiographic analysis was then used to evaluate the cleavage of 125I-single-chain u-PA (prourokinase) in dextran sulfate euglobulins as well as after exposure to kallikrein or beta-factor XIIa. This analysis supported the conclusion that plasma kallikrein-mediated cleavage and activation of single-chain u-PA is the mechanism operative for the development of lytic activity in euglobulin precipitates following activation of the contact system.

Blood Proteins↗
PubMed1987

Monoclonal antibodies directed against human tissue-type plasminogen activator: a characterization of their species specificity, affinity and heavy-chain binding.

Six monoclonal antibodies (mIgG) and a polyclonal antibody (pIgG) directed against human tissue-type plasminogen activator (t-PA) were tested for their species specificity towards human or murine t-PA. Whereas pIgG as well as several mIgGs discriminated poorly between these two t-PA species, one mIgG (clone E3) was highly specific for human t-PA. Inhibition and binding studies of human t-PA by mIgGs revealed high affinity-high inhibitory (E3) as well as high affinity-poor inhibitory (B1) mIgGs. The relative affinity of two mIgGs for human t-PA was found to be equal or even superior to that of pIgG. Immunoblotting of reduced two-chain t-PA and of an isolated heavy chain of t-PA prepared by recombinant DNA technology, showed that the E3 antibody was directed against the heavy chain of t-PA.

Animals↗
PubMed1987

Fibrinolysis in pregnancy: a study of plasminogen activator inhibitors.

During pregnancy the plasma concentration of two different inhibitors of plasminogen activators (PAIs) increases. The only one found in the plasma of nonpregnant women (PAI1) is immunologically related to a PAI of endothelial cells; its plasma activity, as deduced from the inhibition of single-chain tissue-type plasminogen activator (t-PA), increased from 3.4 +/- 2.3 U/mL (mean +/- 95% confidence limits) in the plasma of nonpregnant women to 29 +/- 7 U/mL at term, and its antigen level, measured by a radioimmunoassay, increased from 54 +/- 17 ng/mL to 144 +/- 25 ng/mL. In pregnancy plasma a second PAI (PAI 2) related to a PAI found in placenta extracts was observed. Its level, quantified with a radioimmunoassay, increased from below the detection limit (approximately 10 ng/mL) in normal plasma to 260 ng/mL at term. One hour after delivery, PAI 1 activities and antigen decreased sharply, but the PAI 2 antigen levels remained constant. Three days later, the PAI 1 antigen levels had fallen to normal levels, but the PAI 2 antigen levels were still at least eightfold above the nonpregnant values. During pregnancy, the t-PA and prourokinase (u-PA) antigen concentrations increased 50% and 200%, respectively, whereas the plasminogen and alpha 2-antiplasmin levels remained constant. Despite the large variations in the levels of PAs and PAIs, the overall fibrinolytic activity as measured in diluted plasma by a radioiodinated fibrin plate assay did not change significantly. Just after delivery, a great increase in the t-PA antigen levels was observed. Three to five days after delivery most parameters of the fibrinolytic system were normal again. Our results demonstrate that during pregnancy and in the puerperium profound alterations of the fibrinolytic system occur that are characterized by increases in PAs and their inhibitors, but these alterations do not affect the overall fibrinolytic activity.

Adult↗
PubMed1979

[Acquired von Willebrand's syndrome associated with malignant lymphoma].

The sudden development of multiple bleeding episodes in a 63-year-old patient with malignant lymphoma was shown to be due to the presence of an acquired von Willebrand syndrome, characterized by a prolonged bleeding time and low levels of the factors VIII: C, VIIR:Ag and VIII:Rcof. Crossed immunoelectrophoresis demonstrated diminution of the factor VIII portion with least anodic mobility. Mixing experiments of the patient's and normal plasma revealed a weak (T/2: 4.5 hours) inhibitory activity against the factors VIII:C, VIIIR:Ag and VIII:Rcof. After infusion of 800 units of cryoprecipitate there was rapid destruction (T/2: less than 1 hour) of infused factors VIII: C and VIIIR:Ag and no correction of the bleeding time. Chemotherapy resulted in disappearance of the lymphoma and the hemostatic defect, and its discontinuation in their reappearance. The weak inhibitory activity of the patient's plasma does not fully account for the factor VIII levels observed and other pathophysiological mechanisms, such as adsorption of factor VIII to the malignant lymphocytes, must be considered.

Antigens↗
PubMed1978

The hemostatic mechanism after open-heart surgery. III. Correlation between the appearance of an abnormal protein demonstrated by gel electrophoresis and of an inhibitor of the extrinsic coagulation system (PEC).

A prospective study in 13 patients undergoing open-heart surgery with extracorporeal circulation revealed a marked decrease of the mean one-stage prothrombin time activity from 88% to 54% (p less than 0.005) but lesser decreases of factors I, II, V, VII and X. This apparent discrepancy was due to the appearance of an inhibitor of the extrinsic coagulation system, termed PEC (Protein after Extracorporeal Circulation). The mean plasma PEC level rose from 0.05 U/ml pre-surgery to 0.65 U/ml post-surgery (p less than 0.0005), and was accompanied by the appearance of additional proteins as evidenced by disc polyacrylamide gel electrophoresis of plasma fractions (p less than 0.0005). The observed increases of PEC, appearance of abnormal protein bands and concomitant increases of LDH and SGOT suggest that the release of an inhibitor of the coagulation system (similar or identical to PIVKA) may be due to hypoxic liver damage during extracorporeal circulation.

Aspartate Aminotransferases↗
PubMed1976

[Intermittent pneumatic compression of leg and thigh: a new successful method for the prevention of postoperative thrombosis].

In a prospective study, 54 patients undergoing joint-replacement operations were randomized into a control and a treatment group. In the treatment group low pressure intermittent compression (Phlebo-Dynastat) to calves and thighs was started on the day of operation and continued until patients were fully mobilized. In 34 evaluable patients undergoing total hip arthroplasty the incidence of deep vein thrombosis (DVT) as determined by venography was 43% in the control group and 22% in the treatment group (p = 0.18). In 17 patients undergoing total knee replacement, DVT occurred postoperatively in 70% of the control group but in none of the treatment group (p = 0.002). The difference between the control and Phlebo-Dynastat group when comparing all patients was highly significant (p less than 0.005). Low pressure intermittent venous compression offers a welcome alternative method of thrombosis prophylaxis in patients with increased risk of bleeding.

Air Pressure↗