Biomedical subjects
C Steinmann
Publications and source records attributed to C Steinmann.
Effect of preeclampsia on umbilical cord blood hematopoietic progenitor-stem cells.
OBJECTIVE: The aim of the present study was to determine the influence of preeclampsia on cord blood hematopoietic progenitor-stem cells obtained at delivery because cord blood is increasingly used clinically for stem cell retrieval as an alternative to bone marrow. STUDY DESIGN: Umbilical cord blood was collected from patients fulfilling the criteria for preeclampsia and from gestational age- and birth weight-matched control subjects at delivery (patient/control subjects ratio, 1:2). Cord blood volume and nucleated cell content were measured, and the number of hematopoietic progenitor-stem cells was determined by means of fluorescence-activated cell sorting with the CD34(+) epitope and by means of colony assays with different hematopoietic growth factors. In addition, the expression of adhesion molecules by CD34(+) progenitor-stem cells was examined. RESULTS: In pregnancies affected by preeclampsia, volume and nucleated cell and total CD34(+) cell contents in the collected cord blood were significantly smaller compared with those of control subjects. Furthermore, there was a trend toward a smaller relative number of CD34(+) cells and colony-forming units per nucleated cell in cord blood samples from preeclamptic patients. No difference in the expression of the cell-adhesion molecules leukocyte function-associated antigen 1, very late activation antigen 4, and L-selectin by CD34(+) cells could be found. CONCLUSION: This study shows that preeclampsia affects umbilical cord blood volume and nucleated cell and progenitor-stem cell numbers obtained at birth.
Decreased cord blood yield in post-term pregnancy: a comparative study.
Explore the source record for details and available documents.
Preterm birth and the availability of cord blood for HPC transplantation.
BACKGROUND: Cord blood from deliveries at term can be used for HPC transplantation. The objective of this study was to determine the amounts of cord blood nucleated cells (NCs) and HPCs that were collectable from preterm deliveries. STUDY DESIGN AND METHODS: Cord blood collected from preterm deliveries between 22 and 36 weeks of gestation was compared with regard to volume, NC count (/mL), CD34+ cell count (/mL), and the NC and CD34+ cell counts per cord blood sample and at different gestational ages. RESULTS: A correlation was found between gestational age and NC count (r = 0.52, p<0.001), and an inverse relation was found between gestational age and CD34+ cell count (r = - 0.68, p<0.001). The CD34+ cell count per cord blood sample was independent of gestational age (r = - 0.13, p = NS), and no significant difference between early (22-32 week) and late (33-36 week) preterm deliveries was found (p = 0.870). Comparison with published data from cord blood transplantations revealed that up to one-third of preterm samples contained at least as many NCs (or CD34+ cells) as the median cell dose transplanted (calculated for the median recipient weight) in the respective study. Furthermore, 77 percent of all preterm samples contained at least 1 x 10(7) NCs (and 42% at least 1 x 10(5) CD34+ cells) per kg for transplantation in a recipient of 20-kg body weight, which corresponds to the lower threshold of cells per kg in the graft recommended by Eurocord. CONCLUSION: Preterm delivery should not be a reason to exclude cord blood collection if allogeneic cord blood transplantation in a sibling is planned.
Umbilical cord blood collection before placental delivery during cesarean delivery increases cord blood volume and nucleated cell number available for transplantation.
OBJECTIVE: We sought to determine whether umbilical cord blood collection during cesarean delivery can be improved by collecting cord blood before delivery of the placenta. STUDY DESIGN: Patients undergoing cesarean delivery were randomly assigned to cord blood collection before or after placental delivery. Closed sterile collection systems were used for blood sampling. Cord blood characteristics and maternal outcome parameters were compared between the 2 groups. RESULTS: A total number of 40 patients were available for analysis. No differences in maternal and neonatal characteristics were found. A larger amount of cord blood volume (mean +/- SEM, 93 +/- 7.5 vs 66 +/- 6.6 mL; P =.013) and total nucleated cell number (11.1 +/- 1.2 vs 7.4 +/- 0.8 x 10(8) cells; P =.026) was obtained in the samples collected before compared with those collected after placental delivery. Similarly, there was a trend toward higher total CD34(+) cell number in samples collected in situ (30.0 +/- 6.0 vs 17.4 +/- 2.4 x 10(5) cells; P =.076). Estimated intraoperative blood loss, difference between prepartum and postpartum hemoglobin values, operating time, and puerperal infection rates were similar in both groups. CONCLUSION: If a cesarean delivery is performed, cord blood sampling is more efficacious if performed before delivery of the placenta. This collection method seems beneficial and safe and might therefore be preferably used for related, as well as unrelated, cord blood stem cell banking and transplantation.
Developmental changes in adhesion molecule expressions in umbilical cord blood CD34 hematopoietic progenitor and stem cells.
OBJECTIVE: The purpose of this study was to determine whether expressions of the cell adhesion molecules LFA-1 (CD11a), VLA-4 (CD49d), and L -selectin (CD62L ) on CD34(+) stem and progenitor cells in umbilical cord blood change during gestation. STUDY DESIGN: In a prospective observational study 3-color fluorescence-activated cell sorting was used to assess the levels of expression of CD11a, CD49d, and CD62L on CD34(+) cells in fresh cord blood samples collected at delivery between 22 and 42 weeks' gestation. RESULTS: The relative number of CD34(+) cells decreased as gestational age increased (r = -0.71; P<.001). Conversely, we found significant increases in cell adhesion molecule expression by CD34(+) cells during gestation (LFA-1, r = 0.47; P =.001; VLA-4, r = 0.33, P =.031; L -selectin, r = 0.61; P<.001). Comparisons between grouped samples from early preterm (22-32 weeks' gestation), late preterm (33-37 weeks' gestation), and term (38-42 weeks' gestation) infants confirmed this correlation and revealed that the major increases occurred between early and late preterm gestation. CONCLUSION: These results suggest a role for cell adhesion molecule expression in the process of migration and homing of circulating stem cells to the fetal bone marrow toward the end of pregnancy. The findings may have implications for the use of preterm cord blood for hematopoietic stem cell transplantation and also for prenatal gene therapy.
[Tau protein. A potential biological indicator for early detection of Alzheimer disease].
In 40 patients with Alzheimer's disease (AD), in 5 patients with non-AD dementia and in 36 cognitively normal controls the concentration of protein tau was determined in the cerebrospinal fluid (CSF). Of the AD patients, 19 were very mildly demented (MMSE score from 25 to 28). Even in these patients, CSF tau was significantly more elevated than in controls. In the non-AD patients protein tau was less increased. Among the AD patients there was no association between CSF tau and severity of cognitive impairment or deficit in cerebral blood flow, determined by SPECT. Our findings suggest that CSF tau may be elevated even at the predementia stage of AD and be useful as a biological marker for the early recognition of the disease.
[Attempted suicide in Alzheimer phobia].
Explore the source record for details and available documents.
Fibrinogen Claro--another dysfunctional fibrinogen variant with gamma 275 arginine-->histidine substitution.
Explore the source record for details and available documents.
Binding of calcium ions and their effect on clotting of fibrinogen Milano III, a variant with truncated A alpha-chains.
Calcium ions are known to be required for normal polymerisation of fibrin monomers. Normal human fibrinogen has three high-affinity calcium binding sites. Two of these are located in the D-domains whereas the third binding site was tentatively assigned either to the E-domain or to the C-terminal part of the A alpha-chain. Furthermore, binding of calcium to the low-affinity binding sites (n > or = 10) facilitates fibrin monomer polymerisation. In several abnormally clotting fibrinogen variants, the polymerisation defect was partially normalised following addition of calcium ions. In this study, we show normal binding of calcium to fibrinogen Milano III, a homozygous fibrinogen variant with truncated A alpha-chains (A alpha 452 Gly-Pro-Asp-->Trp-Ser-Stop). These results confirm that the C-terminal parts of the A alpha-chains beyond residue 451 Ile are not involved in calcium binding. The thrombin time was severely prolonged and the final clot turbidity was strongly reduced in fibrinogen Milano III. Moreover, calcium ions did not significantly improve the abnormal clotting behavior of this dysfibrinogen. The polymerisation defect in fibrinogen Milano III appears to be due to truncated A alpha-chains as well as to the disulphide-linked albumin.
Normal binding of calcium to five fibrinogen variants with mutations in the carboxy terminal part of the gamma-chain.
Calcium ions are known to accelerate polymerization of fibrin monomers. Each of the two carboxy terminal domains of normal fibrinogen contains one high-affinity calcium binding site that seems to be situated close to the polymerization site in the gamma-chain. Most hitherto described functionally defective fibrinogen variants showed impaired clot formation. Since the tightly bound calcium ions may influence the conformation of the polymerization site, the question arises whether the abnormal clotting of a dysfibrinogen might be due to defective calcium binding. We investigated binding of calcium to fibrinogen and the effect of calcium on the clotting properties of five heterozygous fibrinogen variants showing normal thrombin-induced fibrinopeptide release but abnormal polymerization of fibrin monomers. Each of these dysfibrinogens has one single amino acid substitution in the carboxy-terminal part of the gamma-chain: fibrinogen Claro (gamma 275 Arg-->His), Milano V (gamma 275 Arg-->Cys), Milano I (gamma 330 Asp-->Val), Bern I (gamma 337 Asn-->Lys), and Milano VII (gamma 358 Ser-->Cys). The shortest thrombin clotting time and the earliest onset of turbidity increase were observed in fibrinogen gamma 358 Ser-->Cys; both parameters were little affected by calcium concentration. In the variant gamma 337 Asn-->Lys, the thrombin time was abnormally prolonged at 0.01 mM Ca2+, but it was normalized at 1 mM calcium. In contrast, the abnormal fibrin polymerization of fibrinogen gamma 330 Asp-->Val was barely improved at increasing calcium concentrations. Both variants with the substitution of gamma 275 Arg, the residue indispensable for normal D:D interactions, showed the slowest rate of fibrin polymerization and the lowest turbidity of fibrin clots at any Ca2+ concentration used. High affinity calcium binding was found to be normal in all five fibrinogen variants studied, suggesting that their abnormal clotting was not due to defective binding of calcium. The gamma-chain in the fragment D1 derived from the variant gamma 337 Asn-->Lys was further degraded by plasmin in the presence and in the absence of calcium, whereas fragments D1 from the other four gamma-chain variants as well as from normal fibrinogen were protected against plasmic degradation in the presence of 1 mM Ca2+.
A frameshift mutation in Exon V of the A alpha-chain gene leading to truncated A alpha-chains in the homozygous dysfibrinogen Milano III.
An inherited dysfunctional fibrinogen variant, denoted as fibrinogen Milano III, was found in a 13-year-old girl suffering from recurrent venous thrombosis. Plasma of the patient exhibited prolonged thrombin time and Reptilase time. Polymerization of fibrin monomers in the presence and absence of calcium ions was strongly impaired. SDS-polyacrylamide gel electrophoresis of reduced fibrinogen showed normal B beta- and gamma-chains, whereas no normal A alpha-chain was detected in the proposita. Immunoblot analysis with the monoclonal antibody Y18, detecting an epitope within the stretch of amino acids A alpha 1-51, revealed an A alpha-chain of about 50 kDa with an intact amino terminus. Immunoblotting with antibodies directed against serum albumin demonstrated the presence of albumin covalently linked to fibrinogen via a disulfide bridge. The structural defect of fibrinogen Milano III was determined by sequence analysis of a single-stranded fragment of genomic DNA amplified by polymerase chain reaction. An insertion of a thymine in the exon V of the A alpha-chain gene after the triplet ATT coding for IleA alpha 451 altered the reading frame and caused premature termination of the protein synthesis (Trp452(TGG)-Ser453(TCC)-Stop454(TGA)). In both parents, normal and mutant alleles were established, leading to duplication of the sequence pattern after the thymine insertion site, whereas the proposita is homozygous for the new mutation in the fibrinogen A alpha-chain gene.
A new substitution, gamma 358 Ser-->Cys, in fibrinogen Milano VII causes defective fibrin polymerization.
Fibrinogen Milano VII is a hereditary fibrinogen variant detected in a woman with no clinical symptoms of bleeding or thrombosis. Thrombin and reptilase clotting times were prolonged in six family members from three generations. Release of fibrinopeptides A and B was normal. Fibrin polymerization was strongly delayed both in the presence and in the absence of calcium. The structural defect was determined by sequence analysis of a 290-bp fragment of genomic DNA amplified by polymerase chain reaction and cloned in M13mp19. The triplet TCT coding for the amino acid residue gamma 358 was found to be replaced by TGT, resulting in the substitution gamma 358 Ser-->Cys. Immunoblot analysis demonstrated the presence of covalently linked fibrinogen albumin and fibrinogen (albumin)2 complexes. Albumin was released from fibrinogen Milano VII by limited reduction with 2-mercaptoethanol. Fibrin polymerization was not normalized after removal of albumin from fibrinogen Milano VII, suggesting that the delayed clot formation is not due to steric hindrance caused by bound albumin but by substitution of gamma 358 Ser by Cys itself. Our results indicate that the residue gamma 358 Ser is essential for normal expression of the carboxy terminal polymerization site on the fibrinogen gamma-chain.
Fibrinogen Milano V: a congenital dysfibrinogenaemia with a gamma 275 Arg-->Cys substitution.
An abnormal fibrinogen was discovered in a clinically asymptomatic woman from Italy. Routine coagulation studies revealed prolonged thrombin and reptilase clotting times and a discrepancy between the plasma fibrinogen levels determined by the clotting assay and electroimmunoassay. Release of fibrinopeptides A and B from fibrinogen Milano V by thrombin was normal. Fibrin polymerization was strongly delayed in the presence of EDTA and was partially corrected at physiological calcium concentration. Normal migration of mercaptolysed polypeptide chains was observed in polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Moreover, there was no apparent abnormality in the charge of the reduced chains of the variant fibrinogen, as judged by two-dimensional gel electrophoresis. A fragment of the gamma-chain gene coding for the amino acids 259-350 was amplified and cloned. The amino acid gamma 275 arginine was found to be substituted by cysteine. Immunoblotting analysis with a rabbit antiserum against human serum albumin indicated that albumin was not linked to the odd sulphydryl group of fibrinogen Milano V. Treatment of fibrinogen Milano V with cysteamine, that is surmised to convert the mutant cysteine to a positively charged lysine analogue, did not improve the clotting properties of fibrinogen Milano V.
Fibrinogen Bern I: substitution gamma 337 Asn-->Lys is responsible for defective fibrin monomer polymerization.
An inherited fibrinogen variant, fibrinogen Bern I, was isolated from plasma of an asymptomatic woman. Routine coagulation studies showed prolonged thrombin and reptilase clotting times. Fibrinogen concentration was diminished when determined by a functional assay, but was normal by the heat precipitation method. The release of fibrinopeptides A and B was not delayed. Two-dimensional gel electrophoresis of mercaptolyzed fragments D of fibrinogen, obtained by digestion with plasmin, showed an abnormal electrophoretic mobility in the gamma-chain remnants of fragments D1 and D2 from fibrinogen Bern I, whereas conversion of D2 to D3 by plasmin resulted in the loss of the abnormal charge, suggesting that the structural abnormality in this variant is located in the region gamma 303 through 356. The molecular defect in fibrinogen Bern I was identified by sequence analysis of genomic DNA amplified by polymerase chain reaction and cloned in M13mp19. The triplet AAC coding for asparagine at position gamma 337 was found to be substituted by AAA coding for lysine. We conclude that the substitution gamma 337 Asn-->Lys in fibrinogen Bern I is responsible for defective polymerization of fibrin monomers and for impaired protection by calcium against plasmic degradation.
Degradation of bradykinin in semen of ram and boar.
The pattern of bradykinin (BK; Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg9)-inact iva ting peptidases in semen of boar and ram was investigated. The degradation of BK in semen was completely abolished by the metalloprotease inhibitors EDTA and o-phenanthroline. Inhibitors of angiotensin-converting enzyme (ACE; EC 3.4.15.1) and phosphoramidon, an inhibitor of neutral metalloendopeptidase (NEP; EC 3.4.24.11), were only partially effective in preventing BK degradation in semen. An additive effect was seen with simultaneous inhibition of both enzymes, resulting in complete abolition of BK degradation. HPLC analysis demonstrated that exogenous BK in semen is cleaved at Gly4-Phe5, Phe5-Ser6 and Pro7-Phe8. These results indicate that NEP and ACE are the main peptidases responsible for rapid BK inactivation in semen. The involvement of other peptidases known to be responsible for BK cleavage in other tissues and body fluids, namely carboxypeptidase N (EC 3.4.12.7), post proline cleaving enzyme (EC 3.4.21.26) and aminopeptidase P (EC 3.4.11.9) was excluded. NEP and ACE were shown to be localized mainly in seminal plasma and to a lesser extent on sperm cells.
[The determination of neutral metalloendopeptidase (enkephalinase A) in biological material].
The simple determination of the Neutral Metalloendopeptidase (NEP, Enkephalinase A) with the known fluorogenic substrate Dansyl-D-Ala-Gly-(pNO2)Phe-Gly is disturbed by high concentrations of the Angiotensin-Converting-Enzyme (ACE). ACE hydrolyzes this substrate too but to a smaller degree. In some tissues and body fluids a further substrate hydrolysis takes place by any indefinite proteases. Finally the enzymatic hydrolysis of the NEP-substrate is inhibited by phosphate ions. A method is proposed for the elimination of this disturbances in the NEP-determination with a phosphate-free buffer using two comparison tests with Lisinopril and o-Phenanthroline. The resulting NEP-activity is calculated very simple thereafter.
[The effect of preventative carazolol treatment on stress reactions in boars during semen collection].
The effect of the beta adrenoceptor blocking agent carazolol on heart and circulatory system, on blood values of the acid-base-equilibrium and on plasma enzymes such as creatine-kinase (CK) and aspartate-amino-transferase (ASAT) was investigated in four clinical healthy boars of the German Landrace and four boars of the Piétrain race before, during and after ejaculation at the phantom. The heart rate during semen collection increased less with treatment than it did without it. The relative diastolic time during exertion was prolonged by carazolol in those boars, which also without pharmacological influence had a very short relative diastolic time. By carazolol injection the systolic blood pressure could be decreased most in those boars, which without treatment had the highest rise of systolic blood pressure during semen collection. Furthermore it was shown, that the highest lactate values, which were found in some boars of the Piétrain race, were reduced most by the influence of carazolol. The blood values of the acid-base-equilibrium were highly negative correlated with the lactate values and changed according to them. The enzyme activities (CK and ASAT) 24 h after semen collection were not influenced by carazolol. Individual differences from boar to boar were evident in all examined parameters and were independent of the effects of carazolol treatment.