Epidemiology of haemoglobin disorders in Europe: an overview

OBJECTIVE

As a result of global population movements, haemoglobin disorders (thalassaemias and sickle cell disorders) are increasingly common in the formerly non-indigenous countries of Northern and Western Europe and in the indigenous countries of Southern Europe. This article presents an overview of the changing picture and a method for assessing service needs.

METHOD

Data on country of birth or ethnic origin of residents are adjusted to obtain the estimated proportions of residents and births in non-indigenous groups at risk for haemoglobin disorders in European countries. The results are combined with prevalence data in each country of origin to obtain country prevalence estimates. Service indicators (annual tests or other interventions required to ensure equitable delivery of treatment and prevention) are then derived by country.

RESULTS

Haemoglobin disorders now occur at comparable frequency throughout Northern, Western and Southern Europe. Annually, there are more affected conceptions in Northern and Western than in Southern Europe, and sickle cell disorders are more common than thalassaemias. There is growing need for health policy-makers to support motivated professionals working to develop optimal patient care, carrier diagnosis, genetic counselling and access to prenatal diagnosis throughout the Region.

CONCLUSION

There is a strong case for pan-European collaboration on haemoglobin disorders to share policies, standards and the instruments required to support them. These include methods for needs assessment, service standards, education and information strategies and materials, and methods for evaluating service delivery.

Improved metabolic control decreases platelet activation markers in patients with type-2 diabetes

BACKGROUND

Cardiovascular disease is associated with platelet dysfunction in patients with diabetes. Hyperglycaemia is known as an independent risk factor for micro- and macrovascular complications, and improvement of metabolic control has shown beneficial effects on diabetic late complications. Our study attempts to clarify the effect of improved metabolic control on platelet activation markers in patients with type-2 diabetes.

MATERIALS AND METHODS

Thirty patients were studied at baseline and 3 months after improvement of metabolic control and compared with an age-matched nondiabetic control group. Platelet activation markers (CD31, CD36, CD49b, CD62P and CD63) were assessed by flow cytometry analysis.

RESULTS

Significantly more activated platelets were detected in patients with diabetes compared with controls. After 3 months' improvement of metabolic control, a significant decline of all platelet activation markers except CD36 was noted. Furthermore a significant correlation between CD62P, CD63 and HbA(1c) levels was observed.

CONCLUSIONS

We conclude therefore that improvement of metabolic control has a beneficial effect on platelet activation. This may have an implication in the pathogenesis of vascular disease in patients with type-2 diabetes.

Risk-factor profile in severe, generalized, obliterating vascular disease

A 74-year-old woman had a history over 25 years of endarterectomy of both renal arteries, iliac venous thrombosis, pulmonary embolism, left internal carotid artery endarterectomy, coronary angioplasty, aortocoronary bypass grafting, occlusion of the right axillary artery, lower-limb claudication due to common iliac artery aneurysm, external iliac artery stenosis, multiple femoral artery stenoses, bifurcational stent grafting, occlusion of the left brachial artery and the right external iliac artery, and stroke. Assessment of the risk-factor profile revealed an absence of classic risk factors but the presence of the factor V Leiden mutation, the methylenetetrahydrofolate reductase AI298C mutation, the HFE C282Y mutation, plasminogen activator inhibitor-1 gene mutation, the -455 G/A fibrinogen gene polymorphism, the epsilon3/epsilon4 apolipoprotein E -675 4G gene polymorphism, and hyperhomocysteinemia. This case shows that severe, generalized, occlusive vascular disease may be due to the combination of various genetic risk factors for atherosclerosis and venous thromboembolism.

[Bone pain after long distance flight as first manifestation of HbSC disease]

A 7-year old Ghanese boy was admitted with repeated bone pain. Multiple bone marrow alterations were seen as the causal factor. HbSC disease was diagnosed by hemoglobin electrophorics. The onset of pain attacks appears to be linked to the long distance flight from Ghana to Austria. Due to severe bone marrow affection, beside symptomatic therapy a long-term treatment with hydroxyurea was started, leading to an HbF increase from 5.1 % to 19.3 %. After a follow-up of 8 months the patient has remained free of complaints.

Severe factor XI deficiency caused by compound heterozygosity for the type III mutation and a novel insertion in exon 9 (codons 324/325 +G)

We investigated a 42-year-old Caucasian woman with severe factor XI deficiency and her family members. Restriction enzyme analysis and DNA sequencing revealed compound heterozygosity in the patient for the known type III mutation, which is a Phe283Leu amino acid substitution in the fourth apple domain causing impaired dimerization and secretion, and for a novel frameshift mutation in exon 9 (codons 324/325 +G), leading to premature termination with lack of parts of the fourth apple domain and the downstream serine protease domain.

A serine/alanine polymorphism in the nucleotide-binding fold-2 of the sulphonylurea receptor-1 (S1369A) is associated with enhanced glucose-induced insulin secretion during pregnancy

The sulphonylurea receptor-1 (SUR-1) regulates glucose-induced insulin secretion by controlling K+-ATP channel activity of the pancreatic beta-cell membrane. In this study, we investigated the putative role of a T/G-polymorphism (exon 33, codon 1369; S1369A) in the adenosine diphosphate-sensing nucleotide-binding fold-2 (NBF-2) of the SUR-1 on glucose-induced insulin secretion during an oral glucose tolerance test in pregnant women (PW; n=182). Compared to PW with the T/T genotype, statistically significant elevated C-peptide concentrations were found 60 min after glucose intake in PW with the T/G and G/G genotype (T/T 9.0+/-0.4 ng/ml vs T/G 10.8+/-0.4 ng/ml or G/G 10.8+/-0.7 ng/ml, p=0.01). Furthermore, compared to PW with T/T genotype the deltaC-peptide (60/0 min) was significantly enhanced in PW with T/G or G/G genotype (T/T 6.7+/-0.3 vs T/G 8.9+/-0.4 or G/G 8.9+/-0.7, p=0.0009). A significant correlation of C-peptide concentrations with blood glucose (BG) 60 min after glucose intake was only found in PW with the T/T genotype (r=0.6, p<0.0004). Similarly, a significant correlation of insulin concentrations with BG 60 min after glucose intake was observed in PW with T/T genotype (r=0.5, p<0.0001) and T/G genotype (r=0.24, p<0.03) but not in PW with G/G genotype (r=0.01, p=0.9). From our data we conclude that in PW with the alanine substitution in the NBF-2 region, the insulin response of the pancreatic beta-cell after glucose intake is enhanced and does not correlate with actual BG levels.

Relative hypoleptinaemia in women with mild gestational diabetes mellitus

AIMS

There is increasing evidence suggesting that leptin plays a major role in the regulation of energy homeostasis, as well as in the neuroendocrine and reproductive systems. Leptin is synthesized in the human placenta. The aim of this study was to relate serum leptin levels during pregnancy to glucose tolerance, body mass index (BMI) and specific metabolic variables, such as specific insulin and proinsulin.

METHODS

A 2-h 75 g oral glucose tolerance test was performed in 221 pregnant women at 22-29 weeks of gestation (median 25th week). Serum leptin was measured using a radioimmunoassay. In 49 women, sequential leptin measurements were performed (during pregnancy and post partum (median 5 months)).

RESULTS

During pregnancy serum leptin was significantly related to body weight (r = 0.49), BMI (r = 0.51), fasting immunoreactive insulin (r = 0.46), specific insulin (r = 0.43) and proinsulin (r = 0.29) (all P-values <0.0001). In women with mild gestational diabetes (GDM, n = 55), leptin levels were lower compared to women with normal glucose tolerance (n = 166) after adjusting for BMI and fasting insulin (26.9 vs. 19.4 ng/ml, P = 0.0001). Leptin was significantly higher during pregnancy compared to post partum (mean +/- SE: 24.3+/-1.5 vs. 19.6+/-1.6 ng/ml, P = 0.0003), even after adjustment for changes in BMI and changes in fasting insulin (P = 0.013).

CONCLUSIONS

Leptin levels are elevated in pregnancy. Women with mild GDM presented with relative hypoleptinaemia compared to women with normal glucose tolerance.

Trp64Arg polymorphism of the beta3-adrenergic receptor gene in pregnancy: association with mild gestational diabetes mellitus

A missense mutation of the beta3-adrenergic receptor gene (Trp64Arg) has been associated with obesity and increased capacity to gain weight in nonpregnant populations. Furthermore, the mutation is a potential modifying factor in the etiology of impaired glucose tolerance and type 2 diabetes. We studied the relation of the beta3-adrenergic receptor genotype to glucose tolerance during pregnancy, a state of physiological insulin resistance. In 179 pregnant women (mean age, 28.5 +/- 0.4 yr), a 2-h oral glucose tolerance test was performed between gestational weeks 20 and 31. The beta3-adrenergic receptor genotype was assessed using restriction fragment length polymorphism. The frequency of the Arg64 allele was 9.15%. In women with mild gestational diabetes (n = 70), as defined by 60 min postload glucose values, the Trp64Arg genotype was more frequent than in women with normal glucose tolerance (n = 109; 26% vs. 11%; P = 0.01). Furthermore, the Trp64Arg polymorphism was associated with increased weight gain during pregnancy (baseline to gestational weeks 20-31) and increased postload glucose, insulin, and C peptide values during the oral glucose tolerance test. The results of the present study extend current knowledge about the association of the Trp64Arg beta3-adrenergic receptor polymorphism with glucose tolerance to a pregnant population. The association with mild gestational diabetes suggests that the impact of the polymorphism may be clinically important during pregnancy, a state of physiological insulin resistance.

Concentrations of circulating P-selectin are increased in patients with newly diagnosed insulin-dependent diabetes mellitus

Endothelial cell activations and/or dysregulations of the coagulation system are crucial parameters for the prognosis of disease in patients with IDDM. Recent data suggest that expression of the adhesion molecules E-selectin and P-selectin are markers of endothelial cell activation and/or platelet activation and might modify immunologic responses after shedding from cell membranes. In patients with newly diagnosed IDDM only limited data on circulating selectins are available. This has prompted us to measure levels of soluble (s) forms of P-selectin and E-selectin in 18 patients with newly diagnosed IDDM and two years after the onset of insulin substitution therapy in comparison to 18 age-matched healthy control subjects. HbA1c and blood glucose levels were significantly higher in patients with new onset diabetes, compared to the same patients after two years of insulin therapy (HbA1c: 12 +/- 3% vs. 7.8 +/- 2%; p < 0.01; blood-glucose: 409 +/- 163 mg/dl vs. 131 +/- 23 mg/dl; p < 0.01), but no correlation between these metabolic parameters and soluble forms of E- and P-selectins were noted. Levels of sP-selectin decreased from 210 +/- 120 ng/ml in newly diagnosed IDDM patients to 127 +/- 75 ng/ml after two years of therapy (p < 0.01) and were similar to those of the control subjects (110 +/- 31 ng/ml). Serum concentrations of circulating E-selectin showed no differences in the three groups (newly diagnosed IDDM: 42 +/- 17 ng/ml; two years later: 43 +/- 19 ng/ml; control subjects: 41 +/- 14 ng/ml; n.s.). Increased levels of sP-selectin together with normal levels of sE-selectin at the onset of IDDM suggest enhanced platelet activation during the initial phase of the autoimmune process and return to baseline levels within two years of the disease.

Haemoglobin O Padova and falsely low haemoglobin A1c in a patient with type I diabetes

Glycated haemoglobin (HbA1c) measured by high performance liquid chromatography (HPLC) in a 20 year old female with insulin dependent diabetes mellitus was consistently within the normal range although her daily blood glucose values were > 11.1 mmol/l. HbA1c measured by immunoagglutination and fructosamine was elevated and correlated with the patient's blood glucose values. The HPLC chromatogram showed an additional peak at HbA0. Electrophoresis of haemoglobin on citrate agar gel revealed an abnormal haemoglobin anodal of HbS. Cellulose acetate electrophoresis and isoelectric focusing demonstrated an additional haemoglobin migrating close to HbA2. Amino acid analysis and DNA sequencing revealed an alpha 30 (B11) Glu-->Lys replacement, that is, haemoglobin O Padova. Investigations of two family members without diabetes revealed the same rare haemoglobin variant. This case showed that this silent haemoglobin mutation caused an additional peak and falsely low HbA1c values when measured by HPLC, the gold standard for this evaluation.

Renal and metabolic effects of 1-year treatment with ramipril or atenolol in NIDDM patients with microalbuminuria

The clinical importance of selection of different antihypertensive drugs for the treatment of diabetic patients is still unclear. Thus we performed a randomised, controlled study in 105 hypertensive non-insulin-dependent diabetic (NIDDM) patients with microalbuminuria over 1 year. Patients received either the angiotensin converting enzyme (ACE) inhibitor ramipril (2.5-5.0 mg/day; in addition 24% of patients also received felodipine) or the beta blocking agent atenolol (50-100 mg/day; in addition 24% of patients also received hydrochlorothiazide). Blood pressure, metabolic control, lipid levels and albumin excretion rate were studied during the follow-up. After 1 year an almost identical fall (p < 0.001) in blood pressure was observed with ramipril (170/100 vs 150/ 85 mmHg, median) and atenolol (180/100 vs 150/ 80 mmHg, median). With ramipril a reduction of total cholesterol (6.3 vs 5.9 mmol/l), of LDL cholesterol (3.8 vs 3.6 mmol/l) and HDL cholesterol (1.3 vs 1.2 mmol/l) was found, whereas triglycerides slightly increased (1.8 vs 2.0 mmol/l). With atenolol a similar reduction of total cholesterol (6.3 vs 5.9 mmol/l), LDL cholesterol (3.8 vs 3.7 mmol/l) and HDL cholesterol (1.4 vs 1.2 mmol/l) and an increase of triglycerides (1.4 vs 1.7 mmol/l) was noted. Metabolic control of the patients was maintained with both ramipril and atenolol treatment. With ramipril treatment urinary albumin creatinine ratio (14.4 vs 13.8 mg/mmol) and creatinine clearance (82 vs 84 ml/min) were constant, but with atenolol an increase of albumin creatinine ratio (13.9 vs 19 mg/mmol, p < 0.001) and a slight decrease of creatinine clearance (80 vs 66 ml/min, p < 0.05, not significant after Bonferroni correction) was observed.

IN CONCLUSION

1-year treatment of NIDDM patients with ramipril or atenolol does not influence metabolic control, the changes in serum lipids were similar. Despite almost identical blood pressure reduction in both groups the albumin creatinine ratio was constant under ramipril, but increased under atenolol treatment.

[Activated protein C resistance--an evaluation of current status]

The discovery of APC resistance and of the factor V Leiden mutation brought a break-through in thrombosis research and has greatly improved our understanding of the pathogenesis of venous thrombosis. In particular, it became obvious that thrombotic disease is the result of multiple factors. However, many clinically relevant questions still remain unanswered: for instance, the individual risk of thrombosis for a gene carrier is difficult to assess, since only some of the factors which may finally lead to thrombosis are presently recognized as such. The functional tests which are in common use today have a number of drawbacks and will soon be replaced by improved methods.

Hemoglobin Sherwood Forest detected by high performance liquid chromatography for hemoglobin A1c

Hb Sherwood Forest has been so far identified in only one patient in 1977. This study describes the second detection of this hemoglobin variant by routine high performance liquid chromatography (HPLC) in a diabetic patient and her healthy grand niece. In both, glycosylated hemoglobin (HbA1c) values were excessively elevated (52%), as determined by HPLC with a cation exchange column. The latex agglutination test showed values of HbA1c in the expected normal range. Citrate agar electrophoresis revealed a hemoglobin variant with a mobility similar to HbF. Amino acid analysis and DNA sequence analysis revealed an Arg-->Thr exchange at codon 104 of the beta-chain. This sequence has been described as Hb Sherwood Forest in 1977. The hemoglobin variant is clinically silent and might be confused with excessively high HbA1c in routine measurement of glycosylated hemoglobin.

Hemoglobin variants recently detected in Austria

Measurement of glycated hemoglobin (HbAtc) is used for routine management of diabetic patients. Glucose linkage to HbAtc reflects mean blood glucose levels during the last 3 months before examination. Various methods for HbA1c determination show abnormal values with hemoglobin variants. In some diabetic patients excessively high HbA1c values with high-performance liquid chromatography (HPLC) led to the detection of Hb Graz. In addition to Hb Graz, other silent hemoglobin variants have been found in Austria. Here we review Hb Graz, Hb Sherwood Forest, and Hb Okayama detected while using HPLC for the measurement of HbA1c in diabetic patients.

Enhanced anticoagulant response to activated protein C in patients with IDDM

Anticoagulant response to activated protein C (APC) was studied in 40 healthy subjects and 67 patients with insulin-dependent diabetes mellitus (IDDM) using a modified activated thromboplastin time assay. Results are expressed in terms of the APC sensitivity ratio (APC SR). In addition, plasma levels of protein C, total and free protein S (PS), coagulation factors V and VIII, and prothrombin fragment 1+2 (F1+2) were measured. Patients with IDDM and a urinary albumin excretion rate (UAER) < 30 mg/24 h showed a median APC SR of 2.5 (interquartile range 2.3-2.9). In patients with a UAER between 30 and 300 mg/24 h, the median APC SR was 2.7 (2.7-2.9). Both values were significantly greater than the median APC SR of 2.1 (2.0-2.5) observed in healthy control subjects (P < 0.001). Also, the percentage of subjects with an APC SR < or = 2.0 was markedly smaller in both patient groups. Factor V and VIII levels were not significantly different between IDDM patients and healthy subjects. Grouping of IDDM patients according to the APC SR revealed significantly enhanced levels of total PS (P < 0.05) and factor VIII (P < 0.01) in patients with a poor anticoagulant response to APC (APC SR < or = 2.0) compared with those with an APC SR > 2.7. The negative correlation of the APC SR in diabetic patients with both coagulation and anticoagulation factors indicates a complex role of this parameter in regulating the coagulation system in IDDM.

Development of a carbohydrate antigen during storage of red cells

BACKGROUND

Changes in surface antigens during the aging of red cells led to the expression of epitopes that can induce an immune response. Recently, irregular antibodies detected in the sera of two patients agglutinated in vitro aged red cells.

STUDY DESIGN AND METHODS

The aging of red cells during storage was examined by flow cytometric analysis using fluorescein isothiocyanate-labeled lectins, fluorescein isothiocyanate-labeled anti-human IgG, and fluorescein isothiocyanate-labeled IgM.

RESULTS

Red cells stored for 1 day and 21 days exhibited no difference in the binding of wheat germ agglutinin, Ulex europaeus agglutinin, or concanavalin A. Only soybean agglutinin showed increased binding to old red cells. IgM antibodies present in the sera of two patients induced strong agglutination of stored red cells, but not of fresh red cells of the same or compatible ABO blood groups. The binding of these antibodies did not involve known red cell antigens and could be significantly inhibited by galactose and mannose in a dose-dependent manner. Staining of red cells with sera from both patients indicated that the antibodies recognized the same structure on stored red cells. The number of binding sites on red cells stored for 21 days was between 7,000 and 10,000 per cell.

CONCLUSION

These results demonstrate that, during storage of red cells, gradual expression of galactosyl residues on the red cell membrane occurs.

Mangelzustände an Antithrombin III, Protein C und Protein S

Mangelzustände an Antithrombin III, Protein C und Protein S sind vielfach mit einem erhöhten Thromboembolierisiko verbunden. Klinische Manifestationen sind beim Antithrombin-Ill-Mangel vorwiegend tiefe Venenthrombosen, während beim Protein-Cund Protein-S-Mangel auch arterielle Verschlüsse vereinzelt Vorkommen. Die Diagnose dieser Mangelzustände ist durch Routinetests heute einfach und zuverlässig möglich. Hingegen ist ein positiver Befund bei Personen mit unauffälliger Anamnese schwierig zu interpretieren. Besonders beim Protein-C-/Protein-S-System dürften ein oder mehrere noch nicht näher definierte Kofaktoren Bedeutung haben, und auch die Rolle des C4b-binding proteins ist nicht in allen Aspekten geklärt.

Ob bei Mangelpatienten die Erfassung des individuellen Thromboembolierisikos mit Hilfe von Aktivierungsmarkern zuverlässig möglich sein wird, ist zur Zeit ungewiß.

Assembly and expression of an intrinsic factor IX activator complex on the surface of cultured human endothelial cells

Endothelial cells expose specific receptors for blood clotting factors and, upon perturbation, can initiate and propagate the reactions of the extrinsic pathway of blood coagulation leading to fibrin formation on the cell surface. The existence of an intrinsic mechanism of Factor IX activation on cultured human umbilical vein cells (HUVECs) was investigated by studies of the interaction between HUVECs and two proteins of the contact activation system, the cofactor high molecular weight kininogen (H-kininogen) and the zymogen Factor XI. In the presence of zinc ions (10-300 microM), 125I-labeled H-kininogen bound to HUVECs in a time-dependent, reversible, and saturable manner, with calcium ions exerting an inhibitory effect on the zinc-dependent binding. Analysis of the binding data by the LIGAND computer program indicated that HUVECs, in the presence of 2 mM CaCl2 and 100 microM ZnCl2 at 37 degrees C, bound 1.14 x 10(7) H-kininogen molecules per cell with an apparent dissociation constant of 55 nM. HUVEC-bound H-kininogen functions as the cell surface receptor for both 125I-labeled Factor XI and 125I-labeled Factor XIa, since HUVECs cultured in contact factor-depleted serum do not detectably bind either the zymogen or the enzyme in the absence of H-kininogen and zinc ions. In the presence of saturating concentrations of H-kininogen, 2 mM CaCl2 and 100 microM ZnCl2, the binding of 125I-labeled Factor XI and Factor XIa to HUVECs was time-dependent, reversible, and saturable, with apparent dissociation constants of 4.5 and 1.5 nM, respectively. HUVEC-bound complexes of H-kininogen and Factor XI generated Factor XIa activity only after the addition of purified Factor XIIa, and cell-bound Factor XIa in turn activated Factor IX, as documented by a 3H-labeled activation peptide release assay for 3H-Factor IX activation. The results indicate that cultured HUVECs provide a surface for the assembly and expression of an intrinsic Factor IX activator complex that may participate in the initiation of blood coagulation at sites of vascular injury.

Hypomagnesaemia in type 2 (non-insulin-dependent) diabetes mellitus is not corrected by improvement of long-term metabolic control

Low levels of magnesium have frequently been reported in diabetes mellitus especially in poorly controlled Type 1 (insulin-dependent) diabetic patients. Furthermore hypomagnesaemia might contribute to insulin resistance in Type 2 (non-insulin-dependent) diabetes. As the influence of improved metabolic control on plasma magnesium levels is unknown in Type 2 diabetic patients we studied magnesium plasma levels in 50 patients 1) before, 2) one and 3) three months after the initiation of insulin therapy or intensified treatment with oral hypoglycaemic agents. Magnesium plasma levels were measured by a colorimetric method and were significantly reduced in diabetic patients compared to healthy control subjects (0.79 +/- 0.01 mmol/l vs 0.88 +/- 0.01 mmol/l; p less than 0.0001). Metabolic control was significantly improved as documented by reduced HbA1C levels in both insulin-treated patients or the patients on oral hypoglycaemic agents (p less than 0.003). However, plasma magnesium levels remained unchanged during the follow-up in the insulin-treated group (1: 0.79 +/- 0.02 mmol/l; 2: 0.81 +/- 0.02 mmol/l; 3: 0.79 +/- 0.01 mmol/l) as well as in the patients on oral hypoglycaemic agents (1: 0.79 +/- 0.03 mmol/l; 2: 0.78 +/- 0.02 mmol/l; 3: 0.84 +/- 0.04 mmol/l). This study shows that even marked improvement of glycaemic control does not correct hypomagnesaemia in Type 2 diabetes. We conclude that hypomagnesaemia might be related to the insulin-resistant state and that possible beneficial effect of chronic magnesium administration should be evaluated in these patients.

Hb Graz or alpha 2 beta 2(2)(NA2)His-->Leu; a new beta chain variant observed in four families from southern Austria

Two abnormal hemoglobins were accidentally detected by cation exchange high performance liquid chromatography with the Diamat system of Bio-Rad Laboratories; the variants eluted together with the fast-moving Hb A1c. Structural analysis of isolated beta chains and sequence analysis of amplified DNA identified a new variant, i.e. Hb Graz that has a His-->Leu replacement at position 2 of the beta chain, in four healthy, apparently unrelated, adults. The second variant was identical to Hb Sherwood Forest or alpha 2 beta 2(104)(G6)Arg-->Thr; it is believed that this may be the second observation of this abnormal hemoglobin.

C1-esterase inhibitor in uncomplicated pregnancy and mild and moderate preeclampsia

Routine coagulation tests and measurement of the plasma levels of C1-esterase inhibitor (C1-INH) and antithrombin III were performed in 17 women with mild preeclampsia, 10 women with moderate preeclampsia and 20 women with uncomplicated pregnancy. All pregnant probands were within the third trimester of pregnancy. 20 non-pregnant women were used as controls. The groups were matched in age and the pregnant ones were also matched in gestational age. C1-INH activity and antigen were significantly reduced (p less than 0.002) in normally pregnant women as compared with non-pregnant ones. Further, C1-INH activity was lower in women with mild preeclampsia and significantly lower in women with moderate preeclampsia (p less than 0.05) as compared with normally pregnant women. None of the plasmatic coagulation tests was indicative of a consumption reaction. We conclude that C1-INH activity and antigen reductions are commonly associated with pregnancy. Furthermore, as markedly lower values can be found in mild and moderate preeclampsia, measurement of the C1-INH activity in pregnant women within the third trimester might proof useful to establish the diagnosis of a preeclamptic condition.

Zinc modulates thrombin adsorption to fibrin

Human thrombin with high affinity to Sepharose insolubilized fibrin monomers (high-affinity thrombin) was used to investigate the effect of Zn(II) on the thrombin adsorption to fibrin. Results showed that at Zn(II) concentrations exceeding 100 mumols/l, thrombin binding to fibrin was decreased concomitant with the Zn(II) concentration and time; at lower Zn(II) concentrations, thrombin adsorption was enhanced. Experimental results were identical by using 125I-labelled high-affinity alpha-thrombin or by measuring the thrombin activity either by chromogenic substrate or by a clotting time method. In contrast, Ca(II) alone (final conc. 3 mmol/l) or in combination with Zn(II) was not effective. However, at higher Ca(II) concentrations (7.5-15 mmol/l), thrombin adsorption was apparently decreased. Control experiments revealed that Zn(II) had no impact on the clottability of fibrinogen, and that the results of the experiments with Ca(II) were not altered by possible cross-linking of fibrin. We conclude that unlike Ca(II), Zn(II) is highly effective in modulating thrombin adsorption to fibrin.

A case of the unstable Hb Genova (beta 28 Leu----Pro) in an Arab child associated with severe haemolytic anaemia and growth retardation

The first case of unstable Hb Genova from North Africa is described. It was found in a 13-year-old girl from Libya suffering from chronic Heinz body haemolytic anaemia and growth retardation. The available data strongly suggest that this case represents a new example for a spontaneous mutation.

A patient of German descent with (delta beta)0-thalassemia carrying the Sicilian type deletion of the delta and beta globin genes

A deletion-type (delta beta)0-thalassemia with elevated production of fetal hemoglobin (Hb F) is described. The patient, homozygous for the disease, presented a clinical picture of beta-thalassemia intermedia. DNA analysis demonstrated that the deletion removed about 13 kb from the beta-globin cluster, including part of delta and the complete beta gene. The deletion appears to be identical to the previously described Sicilian deletion. Its presence in the homozygous state in a patient from Central Europe suggests that the deleted chromosome may be rather prevalent in that area.

Zinc alters fibrin ultrastructure

Turbidimetric studies indicate that Zn(II) accelerates fibrin gelation [decreases clotting time (CT)] and increases maximal fibrin clot turbidity. For any given level of fibrinogen (0.2-2.6 mg/ml), the relative fibrin turbidity of thrombin-induced clots increases with Zn(II) in a concentration dependent manner. Zinc-associated turbidity increases are also observed in the presence of 2 mM (Ca(II). With citrate, similar turbidity increases are observed, though at higher cation levels. Thus, turbidimetry indicates that the gel formed with Zn(II) is coarser, or has thicker fibre strands. SEM micrographs confirm that fibre thickness ranges from 260 A to 2600 A, when Zn(II) levels range from 0-50 uM. With citrate, TEM micrographs reveal a more than 20 X fold increase in fibre diameter (100 A- greater than 2000 A) with higher Zn(II) (less than 1 mM) levels. Based on a fibrin monomer cross-section of approximately 60 A, the electron micrographs indicate that depending on the Zn(II) levels, fibrin strands are composed of between 2 to 40 monomeric fibrin molecules. Thus, at physiologically relevant levels, Zn(II) can drastically modulate fibrin ultrastructure.

[Course and blood coagulation findings following systemic short-term fibrinolysis in acute myocardial infarct]

A series of 16 consecutive patients with acute myocardial infarction was investigated with respect to changes in coagulatory parameters after intravenous short-term treatment with 1,500 000 IU streptokinase (SK) over a period of 90 minutes. Samples for coagulation assays (fibrinogen, thrombin, time activated partial thromboplastin time (aPTT), normotest, thrombin-coagulase time, platelets, antithrombin III, plasminogen and antiplasmin activity, alpha 2-macroglobulin, alpha 1-antitrypsin, factor X a were collected before and immediately after iv SK, and after 4, 8, 12, 24, 36, 48 and 72 hours. Platelets, antithrombin III, factor X a, alpha 1-antitrypsin and alpha 2-macroglobulin showed no changes over the observed period. The concentrations of fibrinogen and the activities of plasminogen and antiplasmin decreased clearly during the first 24 hours, reaching a minimum immediately after SK administration. Thrombin time and aPTT were prolonged for 36 hours, with a maximum in the first hours after lysis.

CONCLUSIONS

Invasive diagnostic and/or therapeutic procedures during the first 24 hours after SK lysis should be carried out only for a definite, strict indication and under repeated control of the coagulatory status. After 24-36 hours there is a trend to normalisation of haemostasis. After 36 hours, surgery may be performed without fear of complications due to abnormal coagulability.

Zinc inhibits FPA release and increases fibrin turbidity

Physiologic concentrations of Zn(II) (4-40 microM) can increase the rate of thrombin-induced fibrin clot formation (decreased clotting time, CT) and increase the turbidity of the fibrin gel. Both the initial and ultimate turbidity (AbS 600 nm) of fibrin gels are increased in the presence of Zn(II). Two techniques were used to elaborate the mechanisms of Zn+2 procoagulant effect. Analytical ultracentrifugation indicates that Zn(II) does not induce the formation of fibrinogen multimers. Radioimmunoassay for FPA indicates that thrombin activation of fibrinogen is decreased by Zn(II), with 50% inhibition of FPA release observed at 35 microM Zn(II). These experiments indicate that the critical feature of Zn(II) procoagulant effect is not due to the induction of fibrinogen proteolysis by thrombin, which is actually decreased. Rather, it appears that Zn(II) accelerates the polymerization step of fibrin assembly and concomitantly modifies fibrin gel structure.

[Changes in antithrombin III values during and after extracorporeal circulation in heart surgery, measured on the day of operation using a chromogenic substrate and a laser nephelometer]

The changes in antithrombin III in 31 patients who underwent open-heart surgery were measured during the period of extracorporeal circulation and afterwards over a total period of 24 hours by means of a chromogenic substrate, as well as by laser nephelometry. Both the actual changes in antithrombin III, as well as the theoretical changes calculated by eliminating the effect of haemodilution are discussed. The functional test indicates that the loss of antithrombin-III activity, in general, is due to the effect of haemodilution. However, marked individual differences were noted in the reaction pattern. The results of nephelometric measurements were inconsistent and seemed to indicate that routine procedures in laser nephelometry are hardly suitable for the purpose of comparison of samples with marked haematocrit differences.

Plasma protein S deficiency in familial thrombotic disease

A family with a history of severe recurrent venous thromboembolic disease was studied to determine if a plasma protein deficiency could account for observed disease. Protein S levels in plasma were determined immunologically using the Laurell rocket technique. The propositus, his mother, his aunt, and his cousin who were clinically affected had 17% to 65% of the control levels of protein S antigen (normal range, 71% to 147%). Since three of these patients were receiving oral anticoagulant therapy, the ratios of protein S to prothrombin, factor X, and protein C in these patients were compared with values for a group of orally anticoagulated controls. These results suggested that protein S is half-normal in all family members with thrombotic disease. Other proteins known to be associated with familial thrombotic disease, including antithrombin III, plasminogen, fibrinogen, and protein C, were normal. Because plasma protein S serves as a cofactor for the anticoagulant activity of activated protein C and because protein C deficiency is associated with recurrent thrombotic disease, it is suggested that recurrent thrombotic disease in this family is the result of an inherited deficiency of protein S.

[Diagnosis of hemoglobinopathies in the clinical laboratory]

This paper describes the methods which are, at present, in common use in clinical laboratories to diagnose haemoglobinopathies. They include simple and more sophisticated techniques of conventional electrophoresis, isoelectric focusing, specific screening tests for certain haemoglobins or groups of haemoglobins and ion exchange chromatography. The value and limitations of these methods are discussed along with recent developments.

[Haemoglobin S/beta thalassaemia in a Greek family: a case study (author's transl)]

A case report is presented of the rare haemoglobinopathy HbS-thalassaemia, type betaS-betathal-O in a Greek family. The special diagnostic features are discussed, with particular reference to the differential diagnosis.