Vitamin K Dependent Proteins in Fetal Hemostasis at Mid Trimester of Pregnancy

The vitamin K dependent coagulation factor activities were measured in 63 normal human fetuses from 19 to 28 weeks of pregnancy. These activities were included between 9 to 28 percent of normal adult levels.

Prothrombin antigen, factor IX antigen and protein C were also measured. There is a good correlation between prothrombin procoagulant activity and antigenicity, suggesting that low level of these vitamin K dependent proteins in fetuses is probably a consequence of liver immaturity.

Absence of Transplacental Passage of Pentosan Polysulfate During Mid Trimester of Pregnancy

Eight women who were going to have an abortion between the 18th and 23rd week of gestation for chromosomal abnormalities or haemoglobinopathies received intravenously 50 mg of pentosan polysulfate (PSP). Maternal results of haemostasis prior and after the injection of the drug were compared. Fetal coagulation parameters were tested on samples obtained by direct puncture of the umbilical cord under ultrasound guidance, 30 min after injection. Results were compared to those of normal fetuses at the same stage of gestation, obtained in the same conditions. In mothers’ plasma, 30 min after injection, APTT was prolonged, factor Xa generation was markedly impaired, and factor V level was deeply decreased. By contrast, no modifications of these parameters were observed in fetal plasma, 30 min after the injection of PSP to their related mothers when compared to control fetuses. Thus the absence of biological modifications induced by PSP injection could demonstrate that this drug does not cross through the placenta.

Placental Transfer of Vitamin K1 and Its Implications in Fetal Hemostasis

Vitamin K status was evaluated using coagulation studies and/ or vitamin IQ assays in a total of 53 normal fetuses and 47 neonates. Second trimester fetal blood samples were obtained for prenatal diagnosis under ultrasound guidance. Endogenous vitamin K1 concentrations (determined by high performance liquid chromatography) were substantially lower than maternal levels. The mean maternal-fetal gradient was 14-fold at mid trimester and 18-fold at birth. Despite low vitamin K levels, descarboxy prothrombin, detected by a staphylocoagulase assay, was elevated in only a single fetus and a single neonate.

After maternal oral supplementation with vitamin K1, cord vitamin K1 levels were boosted 30-fold at mid trimester and 60 fold at term, demonstrating placental transfer. However, these levels were substantially lower than corresponding supplemented maternal levels. Despite elevated vitamin K1 concentrations, supplemented fetuses and neonates showed no increase in total or coagulant prothrombin activity. These results suggest that the low prothrombin levels found during intrauterine life are not due to vitamin K deficiency.

Measurement of Low Molecular Weight Heparin Ex Vivo Activities in Clinical Laboratories Using Various Anti-Xa Assays: Interlaboratory Variability and Requirement for an Agreed Low Molecular Weight Heparin Standard

The only sensitive and convenient assay to assess the biological activity of low molecular weight heparins (LMWHs) is based on the potentiation of activated factor Xa inhibition. Several procedures for measuring the socalled anti Xa activity have been proposed. In this collaborative study including eight laboratories, we have used four different assays (three amidolytic and one clotting based methods) for measuring the anti Xa activity of ex vivo samples obtained after injecting three different LMWHs. The dispersion of the results obtained by calibration against standard heparin could be reduced by using any of the three LMWHs for calibration. A coefficient of variation less than 0.20 between values obtained in different laboratories using a variety of methods seems acceptable. However it is necessary to refer to a common international standard for expressing the results in units and to define, for each of the three products, the therapeutic range.

Ocular Penetration Kinetics of Fosfomycin Administered as a One-Hour Infusion

The penetration of fosfomycin in aqueous humour was studied in 21 patients who were to undergo cataract surgery. All patients received 4 grams of fosfomycin as an infusion lasting one hour. Concentrations of the drug in aqueous humour were measured 1, 2, 4, 6 and 12 hours after the start of infusion. Drug concentrations in aqueous humour and serum were measured by HPCE (High Performance Capillary Electrophoresis). The aqueous humour concentration at one hour was 11.46 mg/l +/- 2.12. Peak concentration was 14.63 mg/l +/- 5.54, reached two hours after the infusion. Concentrations were high until 6 hours and remained significant at 12 hours. These results confirm the excellent diffusion of fosfomycin in aqueous humour, with high levels at 12 hours. They justify its use in intraocular infections, by infusions repeated every eight hours, to maintain concentrations above the MIC 90 for organisms usually susceptible to the drug.

[Bilateral simultaneous central retinal artery occlusion revealing giant cell arteritis]

AIM

To point out the importance of the early diagnosis of giant cell arteritis (GCA) (Horton's disease).

MATERIALS AND METHODS

a case report of a sudden bilateral blindness that had revealed GCA.

CASE REPORT

A 68-year old female patient with a history of elevated blood pressure and diabetes mellitus type 2, was examined in emergency for a right painful headache developed one week previously. In ophthalmological examination, her BCVA was 0.9 and P2 in both eyes. Diagnosis of Horton's disease was not initially done in spite of elevated erythrocytes sedimentation rate (ESR) at 30 mm, protein C reactive (CRP) at 19 mg/l. The patient consulted seven weeks later in emergency for a sudden bilateral blindness associated with severe headache, recent asthenia, and limping of the lower jaw. At that time, visual acuity was reduced to light perception in both eyes whereas ophthalmoscopy revealed a bilateral central retinal artery occlusion (CRAO). ESR was 74 mm and CRP 233 mg/I. Temporal artery biopsy confirmed the diagnosis of GCA. The patient was treated with systemic steroids without visual recovery.

CONCLUSION

This case outlines the importance of the early diagnosis of GCA in order to make possible to start treatment before the occurrence of irreversible complications.

[Contributions of the ex vivo human perfused placenta in the study of placental transfer of drugs]

Perfused human placental lobule was developed during the 1970s. Only this model respects the anatomical features of the human placenta. This approach allows different technical conditions (concentrations of drugs…) without ethical problems. Limitations of this ex vivo model are detailed in this review, also its recent contributions in better understanding of placental passage of drugs.

[Anterior chamber migration of Supramid tube from short Krupin valves after more than 13 years of implantation. Two case reports]

INTRODUCTION

In 2004, the authors had to remove two short Krupin valves because the Supramid tube of these valves implanted 13 years previously had migrated into the anterior chamber.

CASE REPORT

The first case was treated in April 2004, the second in November 2004. These valves had been implanted in January 1991 and August 1983 respectively; both because of insufficient, intense general and local medical treatments for vascular glaucoma: post-traumatic for one and neovascular glaucoma after central retinal vein occlusion for the other.

RESULTS

In 2004 in each case, the authors performed the extraction, with Healon, of the Supramid tube that had migrated into the anterior chamber and the dissection of the previous scleral flap, which allowed them to uncover and extract the Silastic scleral tube whose split distal end continued to allow seepage of aqueous humour. The two lateral Supramid arms used to stitch the valve were also removed. The two valves were replaced with a Molteno glaucoma drainage implant. Follow-up was simple.

DISCUSSION

Since February 1981, several Krupin valves, first short, then long, were placed in the Ophthalmic Ward of the Villeneuve St Georges Hospital in France. The authors discuss their structure and evolution. The design of these valves, at first made of two different materials (an intracameral Supramid tube followed by a intrascleral Silastic tube) evolved toward a draining tube made from the same material for its entire length, preventing the disconnection of the two tubes. A literature review retraces the history of the device and the modifications over time.

CONCLUSION

These old Krupin valves have stabilized the IOP for several years in numerous glaucoma patients who did not respond to intense medical treatments. Their dual-material concept was redesigned in favor of a single tube that could no longer become a mobile intraocular foreign body.

Endophtalmie aiguë récurrente à Enterococcus faecalis après chirurgie de la cataracte : un cas à évolution favorable

INTRODUCTION

Enterococcal faecalis endophthalmitis is an acute type of endophthalmitis that is exceptional because it is rare, can be recurrent, and has a poor functional prognosis.

OBSERVATION

We report a case of recurrent Enterococcus faecalis endophthalmitis after cataract surgery on a 76-year-old woman. After four acute infectious episodes over a few months, this patient recovered without ablation of the IOL. After the classic intravitreous and general antibiotic injections, the treatment required posterior vitrectomy with posterior capsulorrhexis. Only this surgery enabled the cleansing of the vitreous cavity by removing the germs present in the intravitreous abscesses. Despite the responsible germ's virulence, the visual recovery at 7/10 P2 remained stable 2 years after these recurrent infectious episodes.

DISCUSSION

As far as we know, this is the only published case of Enterococcus faecalis endophthalmitis that was cured without ablation of the IOL. A review of the literature shows the rarity of acute Enterococcus faecalis endophthalmitis, characterized by recurrences and a poor visual prognosis. The microbiologic and therapeutic particularities of Enterococcus faecalis endophthalmitis are discussed with the objective of elaborating a therapeutic protocol combining antibiotic therapy, corticotherapy, vitrectomy, and posterior capsulorrhexis while leaving the IOL in place.

CONCLUSION

Enterococcus faecalis endophthalmitis is an ophthalmologic emergency, which requires not only a rapid intervention, but also close follow-up to detect recurrences early and perform vitrectomy and posterior capsulorrhexis with as little delay as possible.

P-glycoprotein expression of the human placenta during pregnancy

OBJECTIVE

To investigate whether the placental expression of P-glycoprotein shows a quantitative difference during pregnancy.

STUDY DESIGN

Villous tissue was collected from chorionic villus samples (13-14 weeks of gestation; n = 3 and 20-25 weeks of gestation; n = 4) and from full-term placentas (38-41 weeks of gestation; n = 28). P-glycoprotein was detected by western blot analysis and quantified by densitometry.

RESULTS

We showed for the first time a significant and progressive two-fold decrease in the mean expression of P-glycoprotein between early and late samples, with a major overlap of values.

CONCLUSION

As P-glycoprotein appears to be involved in drug extrusion, these data suggest that the placenta's ability to protect the fetus from xenobiotics is greater in early pregnancy than at term.

Prenatal Diagnosis of Common Aneuploidies Using Multiplex Quantitative Fluorescent Polymerase Chain Reaction

OBJECTIVE

Prenatal diagnosis of foetal trisomies is usually performed by cytogenetic analysis. This requires lengthy laboratory procedures and it is expensive. Here, we report a retrospective study of quantitative fluorescent polymerase chain reaction (QF-PCR) for prenatal detection of trisomies 13, 18 and 21.

METHODS

QF-PCR was performed on a total of 447 amniotic fluids blindly analysed without any knowledge of the cytogenetic results and 43 samples with known karyotype. All samples were tested with at least 4 small tandem repeat markers specific for each chromosome 13, 18 or 21.

RESULTS

QF-PCR results on amniotic fluid were consistent with conventional cytogenetic data. QF-PCR detected 5 cases of trisomy 21, 2 cases of trisomy 18, 1 case of trisomy 13 and 1 case with Klinefelter's syndrome.

CONCLUSIONS

QF-PCR has proved to be very useful in clinical settings, since it allows the detection of major numerical disorders in a few hours after sampling and thus reduces parental anxiety.

Changes in type B natriuretic peptide (BNP) concentrations during cardiac valve replacement

OBJECTIVE

The aim of our study was to investigate the ability of BNP levels to reveal the immediate post-surgery cardiac function improvement. We measured the perioperative variations in BNP concentrations in patients scheduled for cardiac surgery with cardiopulmonary bypass (CPB), chronic mitral regurgitation, valvular aortic stenosis, or myocardial ischaemia.

METHODS

Three groups were included: patients with coronary artery bypass graft (CABG, group I, n = 14), aortic (AVR, group II, n = 14) or mitral (MVR, group III, n = 7) valve replacement. BNP assay was performed at the induction of anesthesia, immediately after the CPB, at the arrival in the intensive care unit, 4 h, 8 h and 12 h after the arrival in ICU.

RESULTS AND CONCLUSION

The occurring variation in BNP levels after the operation is an increase whatever the corrective surgery, underlying the relative lack of specificity of BNP with regard to the cardiac pathology. Besides iatrogenic cardioplegia one can supposes that cardiac surgery involves other major stimuli such as anesthesia, sternotomia, hemodynamics, post-operative that could influence in a non specific way BNP levels.

[Pellet guns: a persistent threat to eyes]

Following a recent case of bilateral perforating ocular trauma by multiple pellets, the authors reviewed pellet traumatisms treated in the Emergency Department and operated on in the Ophthalmology Department of the Villeneuve-St-Georges Hospital over the past 15 years. At close range, pellet weapon shootings can generate lid, conjunctiva, and powder cornea tattoos; in these cases, the lesions are often unilateral. Shooting at longer range does not result in corneodermic tattoos, but because pellets scatter, binocular lesions frequently occur. The different lesions caused by these nonmagnetic foreign bodies are often very serious. An early, even very early, traumatic cataract is sometimes very difficult to treat in these polytraumatized eyes. The visual prognosis is more reserved, as the impact zones often involve the posterior pole and the macular area. The best recovered visual acuity is 30-35/20, with visual field alterations, but the injury to the eyeball by multiple pellets can generate globe atrophy. The authors stress the gravity of these ocular traumas, fortunately rarer but not completely eradicated since the law of May 6, 1995, which restricted the possession of these pellet guns.

[Air bags and eye injuries: chemical burns and major traumatic ocular lesions--a case study]

The authors report a case of bilateral eye lesions with extended visual sequelae after the inflation of a driver's airbag during a head-on collision. The superficial facial lesions were accompanied by bilateral eye lesions, reaching both the anterior and posterior segments. Bilateral periorbital palpebral hematomas; voluminous bipalpebral edema combined with severe -conjunctival edema, corneal erosions, and edema; bilateral hyphema; pupillary changes with multiple iris sphincter breaks and weak pupillary light reflex only on the right eye; retrocession of the iridocorneal angle; and on fundus examination both retinas had posterior and peripheral hemorrhages and Berlin retinal edema. Five years after the trauma and 4 years after posttraumatic surgery for cataract that had progressively appeared on the left eye, the visual acuity is 25/20 in both eyes notwithstanding a small paracentral scotoma related to a break in the Bruch membrane. A review of the literature shows several types of ophthalmological lesions related to the airbag mechanism, which after combustion of an alkaline powder inflates at a very high speed, resulting in a risk of corneal-conjunctive-palpebral alkaline burns added to an eye contusion, which may be responsible for severe lesions. The American studies distinguish three factors affecting the seriousness of these airbag accidents: (a) wearing glasses, (b) position and size of the driver, and (c) inflation force of the airbag. Wearing a seatbelt is mandatory to minimize the violence of the oculofacial impact. After facial trauma from an airbag, an ophthalmological examination is necessary to assess of the chemical burns of the tissues exposed to the alkaline powder and possible major ocular lesions.

Hyperechogenic fetal bowel: a large French collaborative study of 682 cases

Hyperechogenic fetal bowel is detected in 0.1-1.8% of pregnancies during the second or third trimester. This ultrasound sign is associated with cystic fibrosis or other conditions (e.g., chromosomal anomalies, viral infection) but no large-scale prospective studies have been conducted. This 1997-1998 multicenter study in 22 molecular biology laboratories identified 682 cases of hyperechogenic fetal bowel detected by routine ultrasound examination during the second (86%) or third trimester. The fetal bowel was considered hyperechogenic when its echogenicity was broadly similar to, or greater than, that of the surrounding bone. Karyotyping, screening for viral infection, and screening for cystic fibrosis mutations were performed in all cases. Pregnancy outcome and postnatal follow-up were obtained in 656 of the 682 cases (91%). In 447 cases (65.5%), a normal birth was observed. Multiple malformations were observed in 47 cases (6.9%), a significant chromosomal anomaly was noted in 24 (3.5%), cystic fibrosis in 20 (3%), and viral infection in 19 (2.8%). In utero unexplained fetal death occurred in 1.9% of cases, toxemia in 1.2%, IUGR in 4.1%, and premature birth in 6.2%. This study demonstrates that this ultrasound sign is potentially associated with medically significant outcomes. Having established that the bowel is hyperechogenic, recommended investigations should include a detailed scan with Doppler measurements, fetal karyotyping, cystic fibrosis screening, and infectious disease screening. After birth, newborns require pediatric examination because a surgical treatment may be necessary. This should be combined with clear counseling of the parents.

[Training for adult subclavian venous catheterization: use of real-time echography]

OBJECTIVE

To assess the training in adult subclavian venous catheterization of an inexperienced operator, with two different procedures: ultrasound guidance vs anatomic landmark technique.

STUDY DESIGN

Prospective, comparative study.

PATIENTS AND METHODS

After informed consent, 50 adults were divided in two groups, with an original method of inclusion, designed to assess the training of the operator, which alternated ultrasound guidance (n = 25) and Aubaniac's landmark technique (n = 25).

RESULTS

All the catheterizations have been completed. The success rate at first attempt was higher in ultrasound group than in landmark group, without reaching significance (76 vs 56%). Two arterial punctures were reported in landmark group. With ultrasound guidance, there were 21 puncture sites at the external third and 4 at the medial third of the clavicle. Average access time (skin to vein) was 15 +/- 8 seconds in ultrasound group and 63 +/- 78 seconds in landmark group (p < 0.01), with a significant relation between access time and patient rank in landmark group (r2 = 0.42, p < 0.01).

CONCLUSION

Ultrasound guidance makes the training in adult subclavian venous catheterization easier, and allows inexperimented operator to be rapidly efficient. The use of ultrasound would decrease the incidence of complications by a real time visualization of anatomical structures, and by a more external approach of the vein than in the Aubaniac's technique.

Platelet function point-of-care tests in post-bypass cardiac surgery: are they relevant?

BACKGROUND

Platelet dysfunction is an important cause of excessive bleeding after cardiac surgery. We assessed two platelet function point-of-care tests: the platelet function analyser (PFA-100) and the Hemostatus(TM) in patients with and without excessive bleeding after cardiac surgery with cardiopulmonary bypass.

METHODS

Mediastinal chest tube drainage (MCTD) was measured for the first 6 h in the intensive care unit (ICU). Haematology and coagulation tests were done on arrival in the ICU, and when excessive bleeding occurred (MCTD >1 ml kg(-1) h(-1)) or after 3 h.

RESULTS

Eighteen patients bled excessively and 27 had normal MCTD. Hemostatus measurements were prolonged in those with excessive bleeding compared with the normal group. The times for PFA-100 adenosine diphosphate (ADP) and epinephrine were 91 vs 71 s (P=0.004) and 155 vs 114 s (P=0.02) in the bleeding and normal group s, respectively. None of the Hemostatus or PFA-100 values correlated with total MCTD. Depending on the agonist used, maximum aggregation was 33-81% and 52-86% in bleeding and normal groups, respectively. Only poor correlations were found between PFA-100 epinephrine and maximum aggregation in response to ADP (r=-0.52, P=0.03) or to collagen (r=-0.48, P=0.04).

CONCLUSION

Patients bleeding excessively in the ICU had abnormal measurements in point-of-care tests without a dramatic decrease in aggregation. Except for patients with increased risk of postbypass bleeding, point-of-care tests are not useful for routine use after cardiac surgery.

Chronic administration of verapamil, ketoconazole and carbamazepine: impact on immunological parameters

Inhibitors of P-glycoprotein (P-gp) (verapamil) or cytochrome P-450 (ketoconazole) may reduce IL2 production and T lymphocyte proliferation in vitro. We have examined the effects of chronic oral administration of these drugs and of the cytochrome P450 inductor, carbamazepine, on the hematological and immunological parameters of mice. We found no changes after giving the mice 0.12 mg verapamil, 0.85 mg ketoconazole, or 0.514 mg carbamazepine per mouse for 4 weeks (5 days/week). But giving the drugs for an additional 7 weeks at 0.6 mg (verapamil), 4.25 mg (ketoconazole) or 2.57 mg/mouse (carbamazepine), resulted in significant decreases in monocytes in the verapamil treated group (-51%) and in CD4+ cells in the carbamazepine group (-35%). Chronic oral administration of these drugs reduced the lymphocyte counts of mice by 10-18% and their NK counts by 10-16%. These changes could be due to changes in P-gp function in the transport of IL2, with decreases caused by verapamil and ketoconazole.

A peptide derived from bovine beta-casein modulates functional properties of bone marrow-derived macrophages from germfree and human flora-associated mice

The purpose of this study was to evaluate the immunomodulatory activity of a peptide derived from bovine beta-casein (beta-CN), the beta-CN (193-209) peptide, on mouse macrophages that were obtained either from germfree (GF) or from human flora-associated (HF) mice. Macrophages were derived from bone marrow (BMDM) in the presence of recombinant macrophage colony-stimulating factor and exposed to the peptide or lipopolysaccharide (LPS). Membrane marker expression [F4/80, Mac-1, major histocompatibility complex (MHC) class II antigens] and phagocytic activity were assessed by flow cytometry. Production of tumor necrosis factor-alpha and interleukin (IL)-6 was measured by bioassays and production of IL-1alpha, IL-1beta and IL-12 by ELISA. The expression of cytokine mRNA was determined using semi-quantitative reverse transcription-polymerase chain reaction. The beta-CN (193-209) peptide up-regulated MHC class II antigen expression and phagocytic activity of BMDM from GF and HF mice. Its enhancing effect on phagocytosis was greater than that after LPS stimulation (P < 0.01). The peptide induced notable levels of cytokine mRNA in BMDM from GF and HF mice, but it was a significantly weaker inducer of cytokine secretion than LPS. Nevertheless, although flora implantation had no stimulatory influence on basal MHC class II and basal cytokine levels, cells from HF mice were more susceptible than those from GF mice to the peptide effects on these variables. These results indicate that the beta-CN (193-209) peptide could enhance antimicrobial activity of macrophages without proinflammatory effects.

[Reproducibility and interchangeability of the Thromboelastograph, Sonoclot and Hemochron activated coagulation time in cardiac surgery]

PURPOSE

Despite their common use in cardiac surgery, few studies have evaluated the reproducibility of the Thromboelastograph (TEG), of the Sonoclot (SCT), and of the activated coagulation time with celite (ACT-C) or kaolin (ACT-K) measured with the Hemochron, in clinical conditions of on-site monitoring of hemostasis. This study determined the reproducibility of those measurements, and evaluated the ability of various devices to substitute for the ACT-C.

METHODS

Blood samples collected from 20 volunteers and 21 patients undergoing myocardial revascularization were analyzed in the two channels of the TEG, in two SCT and four Hemochron analyzers. The overall of TEG and SCT coagulation profiles were analyzed by a computerized TEG and an experienced observer respectively. The variation rate (V%) was calculated for each variable. The ability of ACT-K and SCT to substitute for ACT-C under different clinical conditions was evaluated.

RESULTS

ACT-C and ACT-K V% ranged between 5.6% and 10.8% and between 6.7% and 12.4% respectively. TEG and SCT V% ranged between 3.1% and 9.5% and between 5.8% and 33.6% respectively, according to different conditions and parameters. In volunteers and non-heparinized patients, the ACT-C and ACT-K were interchangeable. No other test can substitute for the ACT-C when patients are heparinized during cardiopulmonary bypass (CPB).

CONCLUSIONS

In the clinical conditions of use, on-site hemostasis monitoring devices providing the most reproducible measurements are, in decreasing order, the TEG, the Hemochron and the SCT. In heparinized patients and during CPB, results from different tests are not interchangeable, stressing the importance of establishing appropriate instrument-specific values for monitoring anticoagulation during cardiac surgery.

Maternal-fetal transfer of saquinavir studied in the ex vivo placental perfusion model

OBJECTIVE

This study was undertaken to determine the placental transfer of the human immunodeficiency virus protease inhibitor saquinavir.

STUDY DESIGN

An ex vivo perfused human placental cotyledon model was used. Ten placental perfusion studies were performed, with concentrations of saquinavir in the maternal compartment ranging from 322 to 2197 ng/mL (within reference therapeutic ranges). Drug concentrations were determined by high-performance liquid chromatography.

RESULTS

The mean (+/- SD) fetal transfer rate of saquinavir was 1.8% +/- 1.6%, and the mean (+/- SD) clearance index was 0.05 +/- 0.05. A mean (+/- SD) of 1.6% +/- 3.1% of the perfused saquinavir was retained by the cotyledon. The small amount of saquinavir that crossed the placenta corresponded to the fraction not bound to human serum albumin.

CONCLUSION

The low rate of placental transfer of saquinavir suggests that use of this antiretroviral drug by pregnant women may not lead to significant exposure of the fetus.

[Expandable metal stents in palliative treatment of malignant colorectal stricture. A report of 17 consecutive patients]

OBJECTIVE

Several endoscopic procedures have been used to avoid a colostomy in palliative treatment of occlusive colorectal cancer. The aim of this study was to evaluate in intent to treat the long term effectiveness and safety of self-expanding metal stents as a palliative treatment in patients with neoplastic colonic obstruction.

PATIENTS AND METHODS

From December 1997 to June 2000, seventeen patients were treated with 21 colonic stents. Sites of obstruction were high rectum in 3, sigmoid in 11 and left colon in 3.

RESULTS

Stent placement was successful in 16/17 patients (94%). Relief of bowel obstruction occurred in 13 patients (74%) in the first 48 hours. Expandable metal stent achieved an effective bowel transit until death in 9 of the 17 patients (53%). Clinical complications occurred in 6 patients (35%): 2 perforations, 2 migrations, 1 rectal bleeding and 1 dislocation of the stent. Subsequent colostomy was done in 5 patients.

CONCLUSION

Colonic stenting is an alternative palliative treatment in malignant colorectal stricture. However, morbidity and need for subsequent colostomy should be taken into account.

Placental transfer of pyrimethamine studied in an ex vivo placental perfusion model

Pyrimethamine is used as and anti-infectious agent because of its antifolate properties. Its action is synergistic with that of dapsone and sulfamides on Toxoplasma gondii. The goal of the present study was to evaluate the placental transfer of pyrimethamine in an ex vivo model of perfused human placental cotyledon at term. Human placentas were perfused according to the slightly modified method of Schneider. The pyrimethamine fetal transfer rate was approximately 30%, while cotyledon clearance was about 1.8 ml/min. The placental transfer of pyrimethamine seems to be independent of the maternal concentrations of pyrimethamine, suggesting passive diffusion mechanisms or a nonsaturable active transport at the tested concentrations.

Serum C24 bile acids in the developing human fetus

The C24 bile acids (BA) in the serum of 22 healthy human fetuses between weeks 20 and 37 of gestation were determined by capillary GC-MS. Fetal blood samples were taken in utero from the umbilical cord monitored by echography. There was no correlation between total bile acids (TBA) and gestational age. The TBA concentration was 5.14 +/- 2.13 microM. Primary BA (cholic acid and chenodeoxycholic acid) were the main BA (66.78 +/- 13.47%) with chenodeoxycholic acid being the main one. There were low concentrations of secondary BA (deoxycholic acid and lithocholic acid) (10.28 +/- 7.85%), which formed by intestinal bacterial 7 alpha-dehydroxylation of primary BA in the adult, despite the germ-free gut. The tertiary BA (ursodeoxycholic acid) was also detected (12.06 +/- 9.64%). There was 6 alpha-hydroxylation of chenodeoxycholic acid and of lithocholic acid to produce hyocholic acid and hyodeoxycholic acid respectively. Two 1 beta-hydroxylated BA were detected at different times of gestation. Cholic acid was rarely found in the 6 alpha- and 1 beta-hydroxylated forms. These additional hydroxylations could help to protect the fetal liver against the accumulation of cytotoxic bile acids at a time when other detoxification pathways are poorly developed. Traces of unsaturated bile acids like 3 beta-hydroxy-5-cholenoic acid were detected, showing that 27-hydroxylation of cholesterol does occur.

Preparation and analysis of fetal liver extracts

The aim of this work is to describe the techniques that have been used for preparation and analysis of whole fetal liver extracts destined for in utero transplantation. Nine fetal livers between 12 and 17 weeks of gestation were prepared: cell counts and assessment of the hematopoietic cell viability were performed on cell suspensions. Hepatocytes represented 40 to 80% of the whole cell population. The remaining cells were constituted by hematopoietic cells (mainly erythroblasts), as well as by endothelial cells. The latter expressed CD34 on their surface, interfering with the assessment of CD34+ hematopoietic cells by flow cytometry. Direct visual morphologic control using alkaline phosphatase anti-alkaline phosphatase techniques was needed to differentiate hematopoietic from extra-hematopoietic CD34+ cells. Between 3.0 and 34.6 x 10(6) CD34+ viable hematopoietic cells were collected per fetal liver. Adequate differentiation of these cells into burst-forming units erythroid (BFU-E), colony-forming units granulocyte-macrophage (CFU-GM), and colony-forming units granulocyte erythroid macrophage megakaryocyte (CFU-GEMM) has been shown for each sample in clonogeneic cultures. In conclusion, fetal liver is a potential source of hematopoietic stem cells. Their numeration, based on the presence of CD34, is hampered by the expression of this antigen on other cells contained in the liver cell extract, in particular endothelial cells.

[Diagnosis of materno-fetal toxoplasmosis]

The antenatal diagnosis of congenital toxoplasmosis represents today an important application of molecular diagnostic methods such as PCR. Done directly in amniotic fluid, the PCR for T. gondii is able to detect in utero infected foetus with high probability. Doing so, it precludes to obtain foetal blood and to use more cumbersome and lengthy procedures such as inoculation to cell lines or to mice. Although it is use today in many centres, the molecular diagnosis of T. gondii by PCR is neither commercialized nor standardised. The objective of this report is to present the methodology used in our institution and to establish its degree of validation.

Low-dose aprotinin is ineffective to treat excessive bleeding after cardiopulmonary bypass

BACKGROUND

Uncontrolled clinical experience at our institution suggested that low-dose aprotinin could control excessive bleeding after cardiopulmonary bypass (CPB). A randomized clinical trial was conducted to determine the efficacy of low-dose aprotinin in the treatment of hemorrhage after cardiac surgery.

METHODS

One hundred seventy-one patients undergoing cardiac surgery with CPB were included. Forty-four patients (26%) bled significantly in the intensive care unit (>100 mL/h) and received either aprotinin (200,000 KIU bolus + 100,000 KIU/h for 8 hours) or placebo in addition to our standard management of excessive bleeding.

RESULTS

Median bleeding before study drug administration was not different between aprotinin (200 mL) and placebo (212.5 mL) groups. Bleeding decreased significantly with time and similarly in both groups. Ninety-five percent of patients required transfusions in both groups. Median blood products transfused were 13 and 8 units per patient in the aprotinin and placebo groups respectively (p = NS).

CONCLUSIONS

Routine administration of low-dose aprotinin as part of the treatment protocol to control hemorrhage after CPB does not reduce bleeding or transfusion requirements and, therefore, cannot be recommended.

Immunoglobulins of the human amniotic fluid

PROBLEM

Except for the description of a secretory immunoglobulin (S-Ig) of a low size, no recent study has investigated the molecular status of antibodies in the human amniotic fluid.

METHOD

After separation with a high performance chromatography, we analyzed the different isotypes of amniotic Igs by immunoblotting and ELISA.

RESULTS

IgG is found to be the major isotype and to contain mother-derived tetanus antitoxins. IgA is much less abundant, whereas no IgM can be detected. IgA is monomeric, with a low level of secretory IgA and with various amounts of free secretory component (SC). The presence of a low level of SC-containing immunoglobulin of a low size is confirmed during the last trimester of pregnancy. This molecule contains no alpha chain but includes a Fabgamma fragment noncovalently associated with SC. IgG, IgA, and SC are detected in the fetal urine and, therefore, can reach the amniotic fluid by this route.

CONCLUSION

In addition to the predominant maternal IgG, the amniotic fluid contains different molecular forms of fetal immunoglobulins. Their function as an immune barrier against infection and against mother-derived autoantibodies is discussed.

The intestinal microflora regulates cytokine production positively in spleen-derived macrophages but negatively in bone marrow-derived macrophages

Besides its role as a barrier against potential pathogens, intestinal flora is presumed to protect the host by priming the immunological defense mechanisms. In this respect, the influence of intestinal flora on macrophage precursors was examined, and its modulating effect was compared on LPS-induced cytokine production by macrophages derived from bone marrow and spleen precursors (BMDM and SDM respectively). The regulation of IL-1, IL-6, TNF-alpha and IL-12 production in macrophages from germ-free and from three groups of flora-associated mice, conventional, conventionalized and E. coli-mono-associated mice, was investigated. The whole flora inhibited IL-1, TNF-alpha and IL-12 secretion by BMDM, whereas it had a stimulatory effect on IL-12 secretion by SDM. Implantation of E. coli alone enhanced cytokine secretion by BMDM but had a more limited effect than whole flora on SDM, enhancing only TNF-alpha and IL-12 secretion. Study of expression of mRNA showed a correlation with protein secretion for IL-6 but not for TNF-alpha and IL-1. IL-12 enhancement in BMDM seemed to be dependent on regulation of p35 mRNA expression while it was correlated to increased p40 mRNA expression in SDM. The results demonstrated that intestinal flora modulated bone marrow and spleen macrophage cytokine production in a differential manner and suggested a role for bacteria other than E. coli among the whole flora. The contrasting effects exerted by the intestinal flora on bone marrow and spleen precursors are an interesting observation in view of the different functions of these organs in immunity. The finding that intestinal flora enhanced IL-12 production in spleen is also potentially important since this cytokine is implicated in the determination of the relative levels of Th1 and Th2 responses and plays a pivotal role in host defense against intracellular microorganisms.

Inhibition of platelet aggregation by abciximab but not by aspirin can be detected by a new point-of-care test, the hemostatus

We have investigated the type of platelet defect that can be detected with the Hemostatus test performed with the Hepcon/HMS instrument (Medtronic) designed to investigate platelet function during and after surgery. This assay is based on the comparison of the activated clotting time of whole blood measured in cartridges containing kaolin or kaolin and platelet-activating factor in different concentrations. Addition of platelet-activating factor shortened the blood activated clotting time when the platelet counts were normal. However, when platelet counts were below 70000/microL, the activated clotting time was prolonged in all channels including those without platelet-activating factor showing the influence of platelets in the formation of the clot under the conditions tested. Inhibition of platelet aggregation with c7E3 (abciximab, ReoPro) also induced a much-prolonged activated clotting time, and a similar finding was seen with blood from a patient with Glanzmann's thrombasthenia confirming the need for platelet aggregation and/or the glycoprotein (GP) IIb-IIIa complex. In contrast, the interaction of GP Ib with von Willebrand Factor was not of major importance, since inhibition of this interaction with the anti-GP Ib murine monoclonal antibody, ALMA-12, did not modify the activated clotting time. Furthermore, the activated clotting time measured for patients with an acquired defect in von Willebrand Factor activity were unchanged. Finally, inhibition of thromboxane A2 formation by aspirin did not influence the results of this test. Globally, the Hemostatus test was able to detect major abnormalities of GP IIb-IIIa function in the presence or absence of platelet-activating factor.

High levels of circulating thrombomodulin in human foetuses and children

Thrombomodulin (TM) is an endothelial cell surface proteoglycan with anticoagulant functions, also implicated in cell proliferation, cell-cell adhesion and differentiation. In this study we determined circulating plasma TM (pTM) levels in human foetuses at different stages of pregnancy, at birth and in childhood. TM levels increased with gestational age, the median level reaching a peak of approximately 165 ng/ml between the 23rd and 26th week, thereafter decreasing gradually, reaching a value of 108 ng/ml at birth. pTM continues to decrease progressively during childhood, reaching in the 5-15 years group a median of 56 ng/ml which approaches the adult value. The pTM peak was statistically significant and represents a specific foetal phenomenon as it was independent of the corresponding maternal values. As a whole, the pTM pattern during foetal maturation appears totally different from that of protein C, prothrombin and other coagulation activators and inhibitors and thus, TM may play in the foetus another role in addition to its well-known anticoagulant function.

Haematological parameters of parvovirus B19 infection in 13 fetuses with hydrops foetalis

Thirteen cases of fetal parvovirus B19 infection with hydrops foetalis are reported. Viral DNA was identified by polymerase chain reaction (PCR) of amniotic fluid sampled between the 19th and the 29th week of gestation. Haematological examination revealed severe anaemia in all cases and thrombocytopenia in 11/13 cases, which was severe in two cases. Six fetuses died in utero; two after intrauterine transfusion. Complete recovery was observed in seven fetuses; five cases were treated by intrauterine transfusions, and in two cases spontaneous recovery occurred. Upon follow-up, no case of congenital anaemia was observed.

Human amniotic IgA inhibits natural IgG autoantibodies of maternal or unrelated origin

We show that the natural autoantibody activity of amniotic IgG dramatically increases after purification, and that the IgG-depleted fraction can suppress the activity of IgG natural antibodies from amniotic fluid or from the maternal serum. This suppression is also observed towards serum IgG from unrelated adults but does not impair the tetanus antitoxin activity of serum-derived IgG. Absorption experiments and immunoglobulin separation by gel permeation demonstrate that this suppression is due to monomeric immunoglobulins of the IgA isotype. The inhibition is associated with an anti-F(ab')2 activity of the amniotic IgA, involving hypervariable regions of the IgG as demonstrated by different reactivities towards monoclonal IgG sharing the same family of VH and Vkappa domains. These results indicate that the inhibition of natural autoantibodies not only occurs with fetal and adult serum IgM, as reported by other groups, but also with amniotic IgA, suggesting a general and important phenomenon. In the case of the amniotic fluid, IgA could protect the fetus against maternal IgG autoantibodies without interfering with simultaneously translocated antigen-induced IgG antibodies to pathogens.

Management of fetal and neonatal alloimmune thrombocytopenia

Fetal and neonatal thrombocytopenia can be induced by a maternal alloimmunization against fetal platelet antigens. Alloimmune thrombocytopenia occurs with an incidence of 1/1,000 livebirths and may present either with evidence of damage from a prenatal hemorrhage such as porencephaly or intrauterine death, or with active life-threatening bleeding during the neonatal period. It is due to the destruction of fetal platelets by alloantibodies reacting on specific antigenic sites. In Caucasians, the human platelet antigen 1a (HPA-1a) is the most frequently involved in alloimmune thrombocytopenias, accounting for 80-90% of the cases. Anti-HPA-5b is responsible for a further 5-15% of the cases. This article reviews the clinical aspects, the biological diagnosis and the management, including prenatal sampling and maternal therapy.