COVID-19: A Challenge to the Safety of Assisted Reproduction

There is an increased risk of becoming pregnant through fertility treatments using assisted reproductive technology (ART) during the COVID-19 pandemic. The aim of this review is to gather comprehensive data from the existing literature on the potential risks of fertility management during the pandemic period, and outline strategies to mitigate them, with a focus on the hormonal and surgical procedures of ART. A comprehensive search of the scientific literature on COVID-19 in relation to fertility was conducted in the PubMed database using the keywords "coronavirus," "COVID-19," "SARS-CoV-2" and "pregnancy," "fertility," "urogenital system," "vertical transmission," "assisted human reproduction," "controlled ovarian stimulation," "oocyte retrieval," "in vitro fertilization," "hormones," "surgical procedures," "embryos," "oocytes," "sperm," "semen," "ovary," "testis," "ACE-2 receptor," "immunology," "cytokine storm," and "coagulation," from January 2020-July 2022. Published data on pregnancy and COVID-19, and the interaction of the urogenital system and SARS-CoV-2 is reported. The immunologic and prothrombotic profiles of patients with COVID-19, and their increased risks from controlled ovarian stimulation (COS) and ART surgeries, and how these procedures could facilitate COVID-19 and/or contribute to the severity of the disease by enhancing the cytokine storm are summarized. Strategies to prevent complications during COS that could increase the risks of the disease in pre-symptomatic patients are considered. The impact of SARS-CoV-2 on pre-symptomatic infertile patients presents a challenge to find ways to avoid the increased hormonal, immunologic, and prothrombotic risks presented by the use of COS in ART protocols during the COVID-19 outbreak. Safe ART procedures and recommendations are highlighted.

Reproduction, skin aging, and sleep in middle-aged women

There is a growing trend for women to delay having children, with a significant number of women postponing motherhood until the third or fourth decade of life. At the same time, these middle-aged women may be more concerned about skin aging and use dermatologic procedures to delay or repair the effects of aging, environmental factors, and oxidative stress on the skin. It has been suggested that the use of skin cosmetics and procedures may play a role in the reproductive system, although their possible effects have not yet been clearly elucidated. Another crucial factor that needs to be raised in this context is poor sleep, which seems to have an important relationship with both reduced fertility and accelerated skin aging, especially when it is associated with greater oxidative stress and hormonal imbalance. This review discusses the important triad of sleep, dermatology, and reproduction, a subject that has received relatively little attention; and, given its potentially wide-ranging implications, one that deserves more frequent and detailed consideration in future studies. Understanding this complex web of interactions could help to provide outcomes that include healthier skin, safety, improved self-esteem, and successful fertility treatments, all of which can directly affect quality of life.

Intra-sinusal bone ring concomitant with Le Fort 1 osteotomy: description of a technique

AIM

To present a technical note on intra-sinusal bone ring concomitant with Le Fort 1 osteotomy.

MATERIAL AND METHOD

A 57-year-old man was referred to our Department for full-mouth rehabilitation. Oral examination identified: uncompensated multiple tooth loss and a class 3 skeletal malocclusion. The treatment plan consisted in a Le Fort 1 osteotomy and short-arch dental implant rehabilitation. Intra-sinusal bone ring technique associated with Le Fort 1 osteotomy were carried out under general anaesthesia.

RESULT

High primary retention was clinically observed of both the implant and the bone graft. Radiographic follow-up demonstrated satisfactory healing of the graft and implant osseointegration.

CONCLUSION

Bone ring technique concomitant with Le Fort 1 osteotomy seems to be appropriate to correct jaw discrepancy associated to a single tooth loss of the upper molar region with residual bone height of at least 3 mm to ensure implant primary stability.

P–679 Magnetic resonance imaging (MRI), an alternative method to evaluate the ovarian reserve

Study question

Is magnetic resonance imaging (MRI) a valid method to access antral follicles count (AFC) compared to two-dimensional (2D) transvaginal ultrasonography (USG) and Anti-Mullerian Hormone (AMH) to evaluate the ovarian reserve?

Summary answer

AFC has a high agreement between MRI and USG methods, as well as with AMH. MRI can be an alternative method to evaluate ovarian reserve.

What is known already

In fact, two methods are the most used today to assess ovarian reserve: USG and AMH. The USG is considered the gold standard method for AFC, and contributes to predict and tailor treatment strategies, such as in-vitro fertilization. The major limitations of USG are its user dependency and equipment. Also, there are limitations in displaying a global view of the pelvis and large ovarian lesions. Magnetic resonance imaging (MRI), with its excellent soft-tissue contrast resolution and characteristics, is a useful non-invasive alternative modality to USG. Just one study evaluated MRI and revealed more small size antral follicles compared to 3D-USG.

Study design, size, duration

A prospective cross-sectional observational study was performed in an assisted reproduction techniques (ART) post-graduation program setting from an assisted reproductive center in Sao Paulo, Brazil, which ran throughout 2019–2020, with a total number of 59 patients that were in fertility treatment and needed to undergo to a MRI procedure to evaluate uterine or pelvic diseases as, Myoma, Adenomyosis, endometriosis, and adnexal cysts.

Participants/materials, setting, methods

Patients were evaluated to access the AFC by the MRI method and 2D transvaginal USG, and Anti-Mullerian Hormone (AMH) concentration to evaluate the ovarian reserve. Comparison between methods was done through Wilcoxon signed ranks test and Bland-Altman analysis. Ovarian reserve was classified as follows: very low (<4 follicles/AMH<0.5); low (5–7 follicles/AMH=0.5–1.1); normal (8–15 follicles/AMH=1.1–3.5); normal-high (>15 follicles/AMH>3.5). Weighted Cohen’s kappa was used to verify agreement between MRI, USG and AMH classifications of ovarian reserve.

Main results and the role of chance

Average AFC for USG were 5,55±4.01 for left ovary and 5.55±3.8 for right ovary. Average follicle count for both ovaries was 10±7.07. Regarding MRI, mean counts were 6.44±4.81 for left ovary, 5.65±3.85 for right ovary, and a 11.89±7.89 follicle sum mean count. Average concentration of AMH was 1.79±1.44. The Wilcoxon test and Bland-Altman analyses found differences and systematic biases for comparison between USG and MRI for both ovaries (–2.58; limits of agreement=–14.56 to 9.40, Wilcoxon p = 0,008) and for the right ovary (–1.48; limits of agreement=–8.32 to 5.35, Wilcoxon p = 0,031). There was no difference between methods for the left ovary. Weighted Cohen Kappa coefficients showed substantial agreement between ovarian reserve classifications based on AMH levels, USG, and MRI. The conducted paired comparisons were USG with MRI (k = 0.676), AMH with MRI (k = 0.760) and USG (k = 0.609).

Limitations, reasons for caution

The systematic biases found when comparing USG to MRI methods may suggest a consistent detection of more follicles with MRI procedures in comparison to the USG method. This bias found warrants caution as it must be confirmed, in future studies.

Wider implications of the findings: The MRI method reveals similar ovarian reserve to USG when used the same classification, and a higher agreement to AMH. This suggests that MRI is a reliable method of quantifying antral follicles and can also be adopted when the patient will need to evaluate pelvic pathologies.

Trial registration number

Not applicable

COVID-19: Uncertainties from Conception to Birth

Scientific information on the impact of the new coronavirus (SARS-CoV-2) on the health of pregnant women, fetuses and newborns is considered of limited confidence, lacking good-quality evidence, and drawing biased conclusions. As a matter of fact, the initial impressions that the evolution of COVID-19 was no different between pregnant and non-pregnant women, and that SARS-CoV-2 was not vertically transmitted, are confronted by the documentation of worsening of the disease during pregnancy, poor obstetric outcomes, and the possibility of vertical transmission. The present article aims to compile the data available on the association of COVID-19 and reproductive events, from conception to birth.

Increased prevalence of endocervical Mycoplasma and Ureaplasma colonization in infertile women with tubal factor

Objective

Most women suffering from tubal factor infertility do not have a history of pelvic inflammatory disease, but rather have asymptomatic upper genital tract infection. Investigating the impacts of such infections, even in the absence of clinically confirmed pelvic inflammatory disease, is critical to understanding the tubal factor of infertility. The aim of this study was to investigate whether the presence of endocervical bacteria is associated with tubal factors in women screened for infertility.

Methods

This retrospective cross-sectional study involved 245 women undergoing hysterosalpingography (HSG), screened for endocervical colonization by Chlamydia trachomatis, Neisseria gonorrhea, Ureaplasma urealyticum and Mycoplasma hominis, as part of a routine female infertility investigation between 2016 and 2017.

Results

endocervical bacterial colonization by Chlamydia trachomatis, Ureaplasma urealiticum, Mycoplasma hominis and other bacteria corresponded to 3.7%, 9.0%; 5.7% and 9.8%, respectively. There was no colonization by Neisseria gonorrhea. The prevalence of tubal factor was significantly higher in patients with positive endocervical bacteria colonization, regardless of bacterial species. When evaluating bacteria species individually, the women who were positive for endocervical Mycoplasma hominis had significantly higher rates of tubal factor. Associations between endocervical bacterial colonization and tubal factor infertility were confirmed by multiple regression analysis adjusted for age and duration of infertility.

Conclusion

Besides the higher prevalence of Mycoplasma and Ureaplasma infectious agents, the findings of this study suggest the possible association of endocervical bacterial colonization - not only Chlamydia trachomatis and Neisseria gonorrhea, but also Mycoplasma species with tubal performance.

The Antithrombotic Potential of Dalteparin in Man Assessed Indirectly by Wessler’s Technique

The aim of this study was to demonstrate the effectiveness of a new experimental approach for assessing the antithrombotic potential of low molecular weight heparins (LMWH) such as dalteparin. In this approach, sera obtained from healthy volunteers treated with various i.v. doses of dalteparin (30, 60 or 120 anti-Xa IU/kg) or placebo (physiological saline) were used as the thrombogenic challenge in a Wessler’s stasis model of experimental venous thrombosis in the rat. Sera from placebo-treated volunteers showed a stable thrombogenic activity (0.25 ml/kg of serum producing thrombi of about 50 mg wet weight). Sera from healthy volunteers having previously received dalteparin however demonstrated dose- and time-related reductions in their thrombogenic activity. Half-lives of these effects were 300, 444 and >480 min for 30,60 and 120 anti-Xa IU/kg dalteparin respectively. These values were significantly higher than the corresponding anti-Xa and anti-IIa half-lives.

Rapid Aequorin Loading into Platelets in the Presence of DMSO - Characteristics of the Responses (Changes in Light Transmission and in Calcium) to Various Agonists

We have looked at different parameters which could modify platelet behaviour during and after aequorin loading in the presence of DMSO. There is a decreased platelet reactivity in response to ADP, PAF and A-23,187 which appears to be mainly due to the exposure to EGTA during washing and loading and the 1 ml volume of the test suspension. All the studied agonists (including PMA) which elicit aggregation are able to induce an intracellular Ca2+ change detected with the aequorin probe. By contrast, epinephrine alone induces neither aggregation nor Ca2+ rise, but potentiates the responses to ADP. Different consecutive phases in Ca2+ changes after stimulation with ADP, PMA and A-23,187 can be evidenced. In the presence of external Ca2+, the second component of the Ca2+ change evoked with ADP is dependent on aggregation and the subsequent TXA2 synthesis. When the external medium is Ca2+ depleted, the two Ca2+ peaks induced by ADP disappear whereas a Ca2+ rise persists (endogenous mobilization) with the other agonists, being independent of TXA2 and ADP release. Ca2+ mobilization parallels activation with A-23,187 but not with low concentrations of thrombin.

Does Increased Platelet Aggregation Have a Prognostic Value in the Deterioration of Background Diabetic Retinopathy?

Many case-control studies have suggested that increased platelet aggregation (PA) could be involved in the pathogenesis of diabetic microangiopathy. However, longitudinal data are needed to support this hypothesis. We consider here such an approach in the placebo group (93 diabetic patients) of a controlled clinical trial on the effect of PA inhibitors in the treatment of diabetic retinopathy (Damad program). We have measured spontaneous PA and PA induced by ADP, collagen and arachidonic acid before treatment and yearly during a 3-year period. The assessment of retinopathy was based on the changes in the number of microaneurysms present in the macular field as seen on fluorescein angiograms during follow-up. PA was estimated by maximal decrease in optical density. The lowest ADP concentration still able to induce irreversible aggregation was also determined. No significant correlations between any baseline PA measurements and end point criterion were found (all correlation coefficients lower than 0.20). No significant changes in mean PA were observed during follow-up. Within-subject variation of PA was markedly large accounting for 61% to 98% of the total variance of various measurements. Allowances for the main characteristics of diabetes made no substantial difference to the results. These negative findings can be partly attributed to the lack of reliability of PA tests. In our study, we conclude that PA tests are not useful measures for the prediction of evolution of background diabetic retinopathy.

Severe Protein C Deficiency in Congenital Thrombotic Disease – Description of an Immunoenzymological Assay for Protein C Determination

An immunoenzymatic assay (ELISA) is described for the quantitative assay of protein C in plasma. This technique allows a safe, reliable, and sensitive assay of protein C, and is easily used for routine investigation. Using this technique, a protein C deficiency (0.16 U/ml) was discovered in a 16 year old patient with a history of very severe thrombotic disease. Protein C deficiency was also discovered in his mother (0.62 U/ml) and father (0.50 U/ml). We therefore suggest that this case could represent a homozygous deficiency of protein C.

Questions and Answers on Prothrombin Time Standardisation in Oral Anticoagulant Control

One of the reasons why oral anticoagulants fell into disrepute is the absence of internationally accepted standardised procedures for controlling the level of anticoagulatiori. This deplorable situation resulted in over- and under-coagulation and uncertainty in the therapeutic range. International conformity can now be obtained by using an International Normalised Ratio (INR) which is derived from the individual result obtained in a given plasma sample and the International Sensitivity Index (ISI) of the tissue thromboplastin reagent used. Any thromboplastin reagent can be calibrated against an international primary or secondary W.H.O. reference preparation, so as to obtain its International Sensitivity Index. The new system of reporting the level of anticoagulation was designed and can only safely be applied in patients taking oral anticoagulants.

Intra-Coronary Thrombolysis with Streptokinase or Lys-Plasminogen/Urokinase in Acute Myocardial Infarction: Effects on Recanalization and Blood Fibrinolysis

Forty-two patients with total occlusion of a coronary vessel were treated with intracoronary fibrinolytic agents. Four therapeutic protocols were compared: group I received streptokinase (SK) as a continuous infusion; group II and III received SK as a bolus at different doses and group IV received lysplasminogen (Pg) plus urokinase (UK); maximal doses were 350,000 IU of SK and 250,000 IU of UK plus 75 μK of Pg. Thrombolysis was assessed by coronary angiography. Coagulation studies were performed prior to, 15 min and 6 hr after the end of the thrombolytic treatment. Recanalization was achieved in 27 of the 31 SK-treated patients (87%) and in 7 of the 11 Pg-UK- treated patients (63.6%). The recanalization frequency was the same in the three SK-treated groups, even though when SK was administered as a bolus, the dose was significantly less than when administered on a continuous infusion. Although systemic fibrinolysis occurred in all 4 groups of patients, this effect was less pronounced in the UK-treated patients than in the three SK- treated groups. This study also shows that recanalization can be achieved with a dose of SK lower than the anti-SK antibody level. Haemorrhagic side effects were minimal in all patients studied. Severe defibrination is usually considered a risk of haemorrhage. These preliminary results suggest that bolus injection of SK or the use of UK plus lys-Pg can reduce the level of defibrination and thus the haemorrhagic risk.

Comparative Study of the Activity of High and Low Molecular Weight Urokinase in the Presence of Fibrin

The fibrinolytic or thrombolytic activity of low molecular weight urokinase (LMW-UK) and high molecular weight urokinase (HMW-UK) is not significantly different when measured in a bovine fibrin plate method, in a circulating plasma system containing a 125I-labelled human fibrin clot, or on 125I-fibrin films in culture plates using normal or α2-antiplasmin depleted human plasma.

In a human fibrin plate method however HMW-UK was found to be more active than LMW-UK. In a purified system on human 125I-fibrin films the activation of native or modified human plasminogen by HMW-UK was also found to be more effective than by LMW-UK.

Using a clot lysis test system we did not observe a different inhibition of LMW-UK and HMW-UK upon incubation in human plasma. This is in contrast with previous reports that HMW-UK is inhibited more rapidly in human plasma than LMW-UK.

In a purified system the inhibition rate of LMW-UK and HMW-UK by α2-antiplasmin is the same (rate constants at 25ΰC of 167 ± 9 M−1s−1 and 171 ± 5 M−1s−1 respectively).

The clinical trials available at present used doses of urokinase which were in excess of those required to obtain a maximal fibrinolytic effect. This might explain why in these trials no difference was observed between the thrombolytic effect of LMW-UK and HMW-UK, while in vitro HMW-UK appeared to be more effective. However, one should always be careful to extrapolate in vitro observations as such to the in vivo situation encountered during thrombolytic therapy.

The Amidolytic Activity of the SK-Plasminogen Complex Is Enhanced by a Potentiator which Is Generated in the Presence of Vascular Plasminogen Activator - Role of Fibrin Degradation Products

In the presence of an excess of streptokinase (SK) the amidolytic activity of the plasminogen-SK complex on chromogenic substrates is 12% lower in serum than in the corresponding plasma. However, in subjects in whom venous stasis lead to a shortening of the euglobulin lysis time to less than 60 min (high responders), the amidolytic activity of the plasminogen-SK complex in serum was 60% higher than in the corresponding plasma. Attempts to find alterations of the plasminogen molecule itself which would account for the enhanced activity in high responder serum were negative. No free plasmin was present and the plasminogens isolated from plasma and serum before and after venous stasis had the same amidolytic activity as glu-plasminogen in the presence of an excess of SK. N-terminal analysis of these four plasminogens revealed in each instance glutamic acid.

The enhancement of the amidolytic activity of the SK-plasminogen complex in serum of high responders (potentiator activity) could be reproduced by adding purified tissue plasminogen activator (TA) to native blood before clotting, but not if TA was added to plasma or to prestasis serum. Removal of fibrin degradation products from poststasis serum resulted in the disappearance of potentiator activity. These experiments suggest that fibrin degradation products, generated during clotting in the presence of vascular or tissular plasminogen activator act as a potentiator of the amidolytic activity of the plasminogen SK-complex.

Kinetics of the Inhibition of Plasmin in Acidified Human Plasma

Acid-treated human plasma is a competitive inhibitor of the hydrolysis of D-Val-Leu-Lys-Nan (S-2251) by plasmin. The rate of hydrolysis is decreased to 50% by 750 fold diluted acidified normal plasma and by 60 fold diluted acidified α2-antiplasmin depleted plasma (α2-antiplasmin concentration less than 2%). These findings suggest that α2-antiplasmin is a contributary but not the main competitive inhibitor of acidified plasma. This interpretation is supported by the finding that α2-antiplasmin depleted plasma reconstituted with purified α2-antiplasmin inhibits the hydrolysis of S-2251 by plasmin at a 125 fold dilution following acidification and by the finding that in a purified system acid inactivated α2-antiplasmin inhibits the hydrolysis of S-2251 by plasmin with a Ki of 25 nM. Thus, besides α2-antiplasmin, other plasma proteins which are at least in part eliminated by the removal of α2-antiplasmin from plasma by immunoadsorption appear to be competitive inhibitors for plasmin in acidified plasma. It is suggested that several competitive inhibitors for plasmin are present and/or generated in acidified plasma and that these inhibitors may at least in part be responsible for the variability in the results of measurements of plasminogen and/or plasmin in plasma following acidification.

The Antiaggregating and Antithrombotic Activity of Ticlopidine Is Potentiated by Aspirin in the Rat

Since ticlopidine specifically inhibits ADP-induced platelet aggregation without affecting prostaglandin metabolism, it seemed interesting to evaluate the effect of aspirin with regard to the antithrombotic efficacy of ticlopidine. Ticlopidine was administered orally to rats alone or in combination with aspirin and the efficacy of the association was determined in several experimental models. A synergistic effect of the ticlopidine/aspirin association was demonstrated with regard to ADP- and collagen-induced platelet aggregation measured ex vivo but also in several experimental thrombosis models including silk thread-induced thrombosis in an arteriovenous shunt, wire coil-induced thrombosis and 111In-labelled platelet deposition on the subendothelium following air drying injury of the rat carotid artery. Similar results were obtained with regard to myointimal proliferation following air-induced injury of the rat carotid artery which occurred as a consequence of vascular injury. The ticlopidine/aspirin combination showed only additive-type effects on bleeding time prolongation induced by tail transection in the rat.

Fibrinogen Haifa: Fibrinogen Variant with Absence of Protective Effect of Calcium on Plasmin Degradation of Gamma Chains

The abnormal fibrinogen Haifa is characterized by the fact that calcium present during enzymatic digestion by plasmin does not protect the Haifa D gamma chain against further plasmin attack as it does in normal molecules.

Since calcium binding to fibrinogen, ADP - platelet aggregation cofactor activity and gamma dimerization process induced by factor XIIIa are normal for fibrinogen Haifa, the corresponding sequences in the gamma chain are not involved. It seems rather that the anomaly resides near the gamma 302 plasmin cleavage site that is protected when calcium is bound to the gamma chain and that this affects the availability of the polymerization site located in the C terminal part of the chain.

French Multicentric Evaluation of Recombinant Tissue Factor (Recombiplastin) for Determination of Prothrombin Time

Recombiplastin, a recombinant a human tissue factor, elaborated by Ortho Diagnostic Systems, produced by Baculovirus and relipidated with highly purified phospholipids, was tested as a new reagent for determining prothrombin time (PT) in a French multicentric study. Its intralaboratory- performances, including sensitivity, repeatability, reproducibility and stability, were explored to establish whether its use would reduce the interlaboratory dispersion of PT values, and therefore improve the standardization of oral anticoagulant treatment.

The 9 university hospital hematology laboratories involved in this study used the same type of instrument (KC 10). For 10 consecutive days, they determined PTS on a normal plasma pool, plasma dilutions of 1/2, 1/3 and 1/8, 3 identical lyophilized calibrated plasmas, as well as plasmas from 20 normal subjects, 50 patients on oral anticoagulant therapy with Recombiplastin which has an International Sensitivity Index (ISI) of 1, and 2 commercial thromboplastin extracts (ISI #1 or 2). In the patients on anticoagulants, factors VII, X and V were measured when results were conflicting.

The intra and interlaboratory reproducibilities of Recombiplastin, calculated on the basis of either PTS expressed in seconds, or of the International Normalized Ratio (INR), were good, with coefficients of variation (CV) similar to those observed with the 5 other reagents used by the different laboratories (2% <CV <8%).

The stability of Recombiplastin was excellent, with no variation in PT after 72 h of incubation at 37° C.

A normal PT of 12 s was obtained with Recombiplastin, similar to the values found for the reagents with ISI #2. In the patients on anticoagulants, Recombiplastin gave the longest coagulation times (PTRecombipiastin = 64.2 s vs PTNeoPlastin = 32.8 s, and PTThromborel = 54.4 s). These results suggest that Recombiplastin is highly sensitive to the changes in coagulation induced by anticoagulants. Recombiplastin was more sensitive to factor VII deficiency than any of the other reagents, even those with ISI #1.

The coefficients of correlation between the INRS calculated on the basis of the PTS obtained with Recombiplastin and the INRS based on the PTS for other thromboplastins, were satisfactory (0.85 <R <0.95) but a breakpoint in the slope of the regression curves was observed when INR >4. This observation requires further investigation, particularly in connection with the exact ISI values for Recombiplastin and the other thromboplastins used in this study.

In conclusion, Recombiplastin is stable and sensitive and gives accurate reproducible results. However, the behavior of Recombiplastin is slightly different from that of the commercial reagents whether their ISI is 1 or 2, and its use did not reduce the interlaboratory dispersion of PT values.

Problems of Oral Anticoagulation in an Adult with Homozygous Protein C Deficiency and Late Onset of Thrombosis

We describe a 57-year-old woman with homozygous protein C deficiency and mild thrombotic manifestations consisting of three spontaneous distal deep vein thromboses occurring after the age of 45. Previous surgery and pregnancies had been uneventful. Low but detectable protein C antigen and activity levels (both 20%) were discovered on the occasion of skin necrosis induced by oral anticoagulation. This therapy was interrupted because of skin necrosis and several episodes of disseminated intravascular coagulation (DIC) at the initiation of treatment despite a cautious protocol. No recurrent thromboembolic event has occurred in our patient using prophylactic doses of low molecular weight heparin for 24 months. New therapeutic approaches might be the administration of low molecular weight heparin or oral anticoagulation associated with protein C replacement in the induction period. This case reflects the variability of expression of protein C deficiency as well as the potential hazards of antivitamin K anticoagulation in this disorder.

Multicentric Evaluation of a New Assay for Prothrombin Fragment F1+2 Determination

A multicenter study of a recently developed ELISA for the determination of prothrombin fragment Fl+2 was performed in order to evaluate analytical and clinical aspects.

Mean intra-assay and inter-assay reproducibility were found to be 11.0 and 12.6%, respectively. The measuring range covered by the calibration curve reaches from 0.04 to 10.0 nM/1 Fl+2. Testing 133 healthy subjects a reference range of 0.37 to 1.11 nM/1 Fl+2 (2.5–97.5 percentile) with a median of 0.66 nM/1 F1+2 was calculated. Minor difficulties with blood sampling (venous occlusion for 2 min) did not affect Fl+2 plasma concentrations.

Significantly increased F1+2 levels were measured in patients with leukemia (p <0.0001), severe liver disease (p <0.005) and after myocardial infarction (p <0.01). Elevated F1+2 concentration before the beginning of heparin therapy (1.25 nM/1) decreased to 0.77 nM/1 (p <0.0001) after 1 day of therapy. For patients in the stable phase of oral anticoagulant therapy decreasing Fl+2 concentrations were measured with increasing INR. Fl+2 levels were already significantly reduced in patients with INR <2.0 (0.56 nM/1; p = 0.0005). Thus Fl+2 determination may be helpful in identifying activation processes as well as in monitoring anticoagulant therapy.

Coagulation Assays as Diagnostic Markers of Hepatocellular Carcinoma

With the aim of improving the biological diagnosis of hepatocellular carcinoma (HCC), alpha-fetoprotein (AFP), des-gamma-carboxyprothrombin (DCP) and factor V levels were assayed in 119 patients with HCC and 60 cirrhotic patients without HCC. Among the patients with HCC, increased levels of AFP (>300 ng/ml) and of DCP (>15 mU/ml) vveie ubseived in 36% and 69% of the cases, respectively. None of the 60 patients without TTCC had increased AFP, and one had abnormal DCP; in this patient, DCP level returned to normal value after vitamin K1 injection. No significant correlation was found between increased AFP and DCP, thus indicating that the two tests complement each other for the diagnosis. A factor V level higher than expected from the reduced prothrombin time test of the patient was detected in 50% of patients with HCC and only 7% of those without HCC. No correlation was found between increased factor V and abnormal AFP or DCP The thrombin time, fibrinogen activity to antigen ratio, and polymerization index failed to differentiate between cirrhosis and HCC. We conclude that AFP, DCP and factor V may give complementary informations in the diagnosis of HCC, one of these markers at least being positive in 88% of the patients.

Effect of Standard Heparin and a Low Molecular Weight Heparin on Thrombolytic and Fibrinolytic Activity of Single-Chain Urokinase Plasminogen Activator In Vitro

The effect of unfractioned heparin (UH) and low molecular weight heparin (LMWH) (Kabi 2165 - Fragmin®) on in vitro scu-PA thrombolytic and fibrinogenolytic activity was investigated. Thrombolytic activity was evaluated by following lysis of radiolabeled plasma clot immersed in plasma in presence of scu-PA alone or with either form of heparin. A 200 IU/ml scu-PA concentration produced clot lysis within 7 hr. UH or LMWH led to a slightly faster clot lysis which was statistically significant only at the 2nd and 3rd hour. No significant difference could be evidenced between UH and LMWH effect. During clot lysis, plasmin, generated within the clot led to a gradual transformation of scu-PA to tcu-PA, specially after a 4-hr incubation. Appearance of tcu-PA activity in the plasma surrounding the clot was significantly inhibited by either form of heparin. This finding contrasts with results observed in purified systems and suggests the presence of heparin-dependent plasma factor(s) inhibiting tcu-PA formation or its activity. Possible candidates might be anti-thrombin III and PAI-3.

No fibrinogen breakdown was observed when plasma was incubated for 7 hr at 37° C in presence of scu-PA alone (200 IU/ ml) or with either form of heparin. However, in presence of a plasma clot, an important fibrinogen breakdown was observed during clot lysis reflecting the action of plasmin and/or tcu-PA generated within the clot, in the surrounding plasma. Fibrinogenolysis was less pronounced in the presence of both heparin preparations possibly as a consequence of the reduction in the tcu-PA level. These results underline the importance of plasma factors in the interaction of heparin with plasminogen activators such as scu-PA.

Fibrinogen Troyes - Fibrinogen Metz

Two new cases of congenital dysfibrinogenemia have been discovered. In the first case, “Fibrinogen TROYES”, the abnormality is characterized by a prolonged thrombin clotting time, the defect being due to abnormal aggregation of fibrin monomers. There is no tendency towards excessive bleeding. The abnormality is found to be present with the same intensity in one of the patient’s brothers and one of his sisters.

In the second case, “Fibrinogen METZ”, the abnormality is more pronounced, since, even in the presence of very high thrombin concentrations no clotting occurs. The abnormality is due to a defect in the release of fibrinopeptides, on addition of thrombin. The patient’s blood contains only abnormal fibrinogen. The plasma recalcification time is more prolonged than in the whole blood clotting time. The abnormality is present in both parents in heterozygote form, a milder form than in the patient who is homozygous. The patient has a moderate bleeding tendency, the parents being normal in this respect.

Multicenter Evaluation of a Chromogenic Substrate Method for Photometric Determination of Prothrombin Time

A multicenter study of a chromogenic substrate method for photometric determination of prothrombin time was conducted in order to evaluate its clinical application. Seven laboratories pailicipaled in the study using a total of 742 plasma samples from 417 patients on oral anticoagulant therapy, 261 healthy subjects and 64 patients with different diseases especially of the liver as well as 30 patients with hereditary deficiency of coagulation factors II, V, VII, X. The chromogenic PT method was compared to a standardized coagulometric PT assay which uses the same sensitive human placenta thromboplastin calibrated against international reference preparations. A high correlation of the prothrombin ratio values of the chromogenic and the coagulometric assay was obtained in 402 plasma samples (r = 0.940; y = 1.02x − 0.1). The study showed that the chromogenic PT reagent is sensitive to deficiency of the coagulation factors of the extrinsic pathway but not affected by heparin up to 1 IU/ml because of the heparin antagonist added. The precision (coefficient of variation) of the photometric method ranged between 0.6 and 3% (intraassay CV) and between 1.4 and 5.8 (interassay CV). The International Sensitivity Index (ISI) obtained for the used lot was 1.09. The therapeutical range in percentage activity for patients in a stable phase of an anticoagulant therapy was found to be from 15 to 27 percent of normal. The results of the clinical evaluation proved the good comparability of the new chromogenic PT test with coagulometric methods, its high factor sensitivity, good reproducibility and easy performance.

Présence d’un Antigène Plasmatique Indispensable à la Stabilisation de la Fibrine dans Deux Cas de Déficit Congénital en Facteur XIII

L’étude d’un immun sérum anti-facteur XIII montre que celui-ci est bien capable de neutraliser l’activité stabilisante de la fibrine du plasma.

Le plasma de deux sujets ayant un déficit en facteur XIII a été étudié au moyen de cet anti-sérum par différentes méthodes: immuno-électrophorèse, inhibition de l’hémagglutination passive, neutralisation de l’inhibition par l’immunsérum de l’activité biologique du facteur XIII.

Dans le plasma de ces deux patients, l’antigène spécifique de l’immunsérum étudié a été retrouvé à un taux normal.

Ces résultats sont compatibles avec deux hypothèses: ou bien il s’agit chez ces patients, non pas d’un déficit quantitatif mais d’une anomalie structurale du facteur XIII le privant de son activité biologique ; ou bien un deuxième facteur protéique est nécessaire à la stabilisation de la fibrine, facteur qui serait absent chez nos deux malades.

Fibrinolysis and Thrombosis: Pathways and Inhibitors

The mechanism of fibrinolysis has been reviewed taking into account its two pathways extrinsic and intrinsic and the important role of α 2plasmin inhibitor. A clear distinction is now well documented on the mechanism of fibrinolysis in a liquid phase and in a solid phase.

The role of fibrin as an important trigger of fibrinolysis in vivo is demonstrated.

Finally a relationship between hypofibrinolysis and thrombosis is highly probable.

Double-Blind Trial of the Efficacy of Troxerutin in Chronic Venous Insufficiency

Objective:

To evaluate the efficacy of troxerutin in chronic venous insufficiency.

Design:

Randomized, double-blind, multicentre, prospective controlled trial.

Setting:

Hôtel Dieu Hospital and Notre Dame de Bon Secours Hospital, Paris, France.

Patients:

Sixty-nine patients with truncal varicose veins.

Intervention:

After a single-blind 15-day placebo run-in period, one group ( n = 34) received troxerutin 3500 mg daily for 2 months. The other group ( n = 35) received a placebo.

Main outcome measures:

Subjective symptoms, ankle circumference, venous refilling time with photoplethysmography, erythrocyte aggregation using the SEFAM aggregameter and fibrinogen level.

Results:

Leg aching ( p < 0.001) and venous function score ( p < 0.001) improvements were significantly higher in the troxerutin group (83% and −3.7) compared with the placebo group (23% and −0.7). A significant difference in favour of troxerutin was found for erythrocyte aggregation kinetic indexes ( p < 0.001) and dissociation threshold ( p < 0.01).

Conclusions:

This study confirmed the dual action of the drug: a parietal effect and a rheological effect.