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J P Cambus

Publications and source records attributed to J P Cambus.

At least 19 recordsLinked to original sources
PubMed1999

Evaluation of the Vega haematology analyser in a university hospital setting.

The performance of the ABX Vega haematology analyser was compared with that of the Sysmex NE-8000, with specific attention to flagging performance and ergonomics. Eight hundred routine samples underwent precision and interinstrument variability studies and 168 samples corresponding to various blood disorders were studied meanwhile. Results from the two instruments gave excellent correlation (r > 0.900) for most parameters except MCHC (r = 0.114), basophil and monocyte percentages (r = 0.617 and 0.552, respectively). The reproducibility, repeatability, linearity, carry-over and stability of the Vega were satisfactory; 'flagging' occurred in 31% of routine samples with sensitivity 88.8%, specificity 41.3% and positive predictive value 85.7%. Various flags appeared in 91% (42/46) of cases where blast cells were microscopically identified. In the four remaining cases, CBC anomalies would themselves have justified microscopic examination of a smear. On 'CBC only' mode reagent consumption was significantly reduced. In the laboratory the analyser was best appreciated for its user-friendliness.

Autoanalysis↗
PubMed1998

Pharmacodynamics and tolerance of two nadroparin formulations (10,250 and 20,500 anti Xa IU x ml(-1)) delivered for 10 days at therapeutic dose.

Venous thromboembolism may be efficiently treated by once-a-day (o.d.) administration of a high dose of low molecular weight heparin (LMWH) instead of administration of the same total dose in two injections a day (b.i.d.). To reduce the volume of the subcutaneous (s.c.) injection, a more concentrated form of the drug is advisable. This study was designed to compare the bioavailability of 2 formulations of nadroparin containing 10,250 and 20,500 anti-Xa IU x ml(-1) respectively. This was an open, randomized, cross-over study where 12 healthy volunteers (age 18-35) were enrolled. They received either 90 anti-Xa IU x kg(-1) b.i.d. of the 10,250 IU preparation (treatment A), or 180 anti-Xa IU x kg(-1) o.d. of the 20,500 IU preparation (treatment B) for 10 days. On day 1, the subjects were sampled between 0 and 12 h (treatment A) or between 0 and 24 h (treatment B). On day 10, they were sampled between 0 and 12 h and between 12 and 24 h (treatment A) or between 0 and 24 h (treatment B). Anti-Xa and anti-IIa activities were determined by specific chromogenic assays. The main result of the study was that the bioavailability of the anti-Xa activity of the 2 nadroparin formulations was equivalent, as shown by the comparison of the AUC(0-12 h) plus AUC(12-24 h) (treatment A) and the AUC(0-24 h) (treatment B), calculated on day 10. This study also allowed a number of interesting observations to be made. 1) Between day 1 and day 10, there was an accumulation of the anti-Xa activity for treatment A but not for treatment B (accumulation factors: 1.6 and 1.1 respectively); 2) On day 10, the AUC(0-12 h) were slightly but significantly lower than the AUC(12-24 h) suggesting a circadian effect for anti-Xa and anti-IIa activities; 3) the clearance of the anti-Xa activity was comparable at the 2-dose regimens, while that of the anti-IIa activity was lower in treatment B than in treatment A, indicating a significant dose effect for the pharmacodynamics of the longer heparin chains; 4) On average, the clearance of the anti-IIa activity was twice as high as that of the anti-Xa activity; 5) For treatment B, significant APTT prolongations were noticed at Tmax (prolongation factor: 1.7 +/- 0.25), in relation with the anti-IIa activity (0.3 +/- 0.1 IU x ml(-1)).

Adolescent↗
PubMed1998

Erythrocyte hyperaggregation and thrombogenic dysfibrinogenemia.

Erythrocyte aggregation was measured in 12 patients with congenital dysfibrinogenemia. The results showed hyperaggregation in four patients who had presented a thrombotic disorder, while aggregation was entirely normal in patients with asymptomatic dysfibrinogenemia. None of the four symptomatic patients had any other anomaly of hemostasis, in particular no coagulation inhibitor deficit or anti-phospholipid antibodies. The possible involvement of erythrocyte hyperaggregation in the thrombotic process is discussed.

Adult↗
PubMed1997

The routine determination of the endogenous thrombin potential, first results in different forms of hyper- and hypocoagulability.

The area under the thrombin generation curve (the endogenous thrombin potential; ETP) has been proposed as a parameter for plasma-based hypercoagulability and to monitor anticoagulant treatment. We present an ETP assay for the routine laboratory using a centrifugal analyser. Throughput is 30 samples/h, within and between run imprecision is 4-5.6%. Suitable substrates were developed for the ranges of 10-500% and 2-100% of normal. Independent of tissue factor concentration (if > 4 pM), the normal value of the extrinsic ETP is 384.8 +/- 51.7 nM.min. The intrinsic ETP, triggered by ellagic acid, is 414 +/- 41 nM.min. The ETP is decreased to 15 and 35% of normal by oral anticoagulation (INR 2.5-4.0) and by heparin administration (APTT 1.5-2.5 x control). The ETP is increased in untreated subjects with congenital antithrombin deficiency and in women using oral contraceptives. In deep vein thrombosis (phlebographically confirmed), it is increased by 29.4% (extrinsic) and 53% (intrinsic). In (angiographically assessed) coronary artery disease the increase is by 10% and 17% respectively.

Adolescent↗
PubMed1996

Automated technical validation--a real time expert system for decision support.

Dealing daily with various machines and various control specimens provides a lot of data that cannot be processed manually. In order to help decision-making we wrote specific software coping with the traditional QC, with patient data (mean of normals, delta check) and with criteria related to the analytical equipment (flags and alarms). Four machines (3 Ektachem 700 and 1 Hitachi 911) analysing 25 common chemical tests are controlled. Every day, three different control specimens and one more once a week (regional survey) are run on the various pieces of equipment. The data are collected on a 486 microcomputer connected to the central computer. For every parameter the standard deviation is compared with the published acceptable limits and the Westgard's rules are computed. The mean of normals is continuously monitored. The final decision induces either an alarm sound and the print-out of the cause of rejection or, if no alarms happen, the daily print-out of recorded data, with or without the Levey Jennings graphs.

Animals↗
PubMed1996

A data management software for the Sysmex NE 8000 haematology analyser.

The Sysmex NE 8000 (TOA-Japan) is a haematology analyser that performs blood cells count and leukocyte differential count. For facilitating the work of technical validation, we developed a software adapted to any IBM or compatible PC running under MS-DOS, to manage the analyser. Data are automatically collected via the RS-232 interface from the analyser or keyed in for the other techniques. The software deals with 64 different analyses entirely "user defined". Six technical alarms of the analyser are taken in account for red or white cells and platelets. An "electronic worksheet" presents the results or alarms with 10 patients to a page. This enables the lab technician to assess the coherence of the various data and to perform verifications or complementary tests if necessary. As an option, a blinking asterisk can signal any results out of predetermined range. By moving the cursor through the table, a test result can be deleted, modified or added. A function displays the patient previous files in a window because the data are recorded in long term archives at the end of the day. This long term recording allows a search of previous files to decide additional tests if the patient is unknown. If the patient is known, with additional tests previously performed, this procedure is time saving. A daily archive function classifies and prints the whole day's work in alphabetical order. A protocol of communication allows a connection to a mainframe computer Bayer-Technicon. This program and the user's manual are free of charge, available on request from J. P. Cambus.

Blood Cell Count↗
PubMed1996

Predicting daily maintenance dose of fluindione, an oral anticoagulant drug.

Due to large inter-individual variations, the dose of vitamin K antagonist required to target the desired hypocoagulability is hardly predictible for a given patient, and the time needed to reach therapeutic equilibrium may be excessively long. This work reports on a simple method for predicting the daily maintenance dose of fluindione after the third intake. In a first step, 37 patients were delivered 20 mg of fluindione once a day, at 6 p.m. for 3 consecutive days. On the morning of the 4th day an INR was performed. During the following days the dose was adjusted to target an INR between 2 and 3. There was a good correlation (r = 0.83, p < 0.001) between the INR performed on the morning of day 4 and the daily maintenance dose determined later by successive approximations. This allowed us to write a decisional algorithm to predict the effective maintenance dose of fluindione from the INR performed on day 4. The usefulness and the safety of this approach was tested in a second prospective study on 46 patients receiving fluindione according to the same initial scheme. The predicted dose was compared to the effective dose soon after having reached the equilibrium, then 30 and 90 days after. To within 5 mg (one quarter of a tablet), the predicted dose was the effective dose in 98%, 86% and 81% of the patients at the 3 times respectively. The mean time needed to reach the therapeutic equilibrium was reduced from 13 days in the first study to 6 days in the second study. No hemorrhagic complication occurred. Thus the strategy formerly developed to predict the daily maintenance dose of warfarin from the prothrombin time ratio or the thrombotest performed 3 days after starting the treatment may also be applied to fluindione and the INR measurement.

Administration, Oral↗
PubMed1996

D-dimer test and diagnosis of deep vein thrombosis: a comparative study of 7 assays.

The current D-Dimer ELISA methods provide high sensitivity and negative predictive value for the diagnosis of deep vein thrombosis but these methods are not suitable for emergency or for individual determination. We have evaluated the performance of 3 newly available fast D-Dimer assays (Vidas D-Di, BioMérieux; Instant IA D-Di, Stago; Nycocard D-Dimer, Nycomed) in comparison with 3 classic ELISA methods (Stago, Organon, Behring) and a Latex agglutination technique (Stago). One-hundred-and-seventy-one patients suspected of presenting a first episode of deep vein thrombosis were investigated. A deep vein thrombosis was detected in 75 patients (43.8%) by ultrasonic duplex scanning of the lower limbs; in 11 of them the thrombi were distal and very limited in size (< 2 cm). We compared the performance of the tests by calculating their sensitivity, specificity, positive and negative predictive value for different cut-off levels and by calculating the area under ROC curves. The concordance of the different methods was evaluated by calculating the kappa coefficient. The performances of the 3 classic ELISA and of the Vidas D-Di were comparable and kappa coefficients indicated a good concordance between the results provided by these assays. Their sensitivity slightly declined for detection of the very small thrombi. Instant IA D-Di had a non-significantly lower sensitivity and negative predictive value than the 4 previous assays; however its performance was excellent for out-patients. As expected, the Latex assay had too low a sensitivity and negative predictive value to be recommended. In our hands, Nycocard D-Dimer also exhibited low sensitivity and negative predictive value, which were significantly improved when the plasma samples were tested by the manufacturer. Thus significant progress has been made, allowing clinical studies to be planned to compare the safety and cost-effectiveness of D-Dimer strategy to those of the conventional methods for the diagnosis of venous thrombosis.

Adolescent↗
PubMed1994

Computer program for connection and data management of an automated coagulation system: the KC 10.

In Europe, the KC 10, manufactured by Amelung Germany, is one of the instruments most commonly found in coagulation laboratories. For facilitating the work of technical validation, we wrote a software adapted to any IBM or compatible PC running under MS-DOS, to manage the analyser performance. Data are automatically collected via the BCD interface from the analyser or keyed in for the other techniques. The software deals with 64 different analyses entirely 'user defined'. An 'electronic worksheet' presents the results, by page of ten patients. This enables the laboratory technician to assess the coherence of the various data and to perform verifications or complementary tests if necessary. As an option, a blinking asterisk can signal all results outside predetermined range. By moving the cursor through the table, a test result can be deleted, modified or added. A function displays the patient's previous files in a window because the data are recorded in long-term archives at the end of the day. This long-term recording allows a search of previous files to decide additional tests if the patient is unknown. A daily archive function classifies and prints the whole day's work in alphabetical order. A protocol of communication allows connection to a mainframe Bayer-Technicon computer. This program and the user's manual are free, available on request from address above.

Blood Coagulation Tests↗
PubMed1994

A data management program for the Electra 800 automatic analyser.

The Electra 800 automatic coagulation analyser rapidly performs most chronometric coagulation tests with high precision. To facilitate data handling, software, adaptable to any PC running under MS-DOS, was written to manage the analyser. Data are automatically collected via the RS232 interface or can be manually input. The software can handle 64 different analyses, all entirely 'user defined'. An 'electronic worksheet' presents the results in pages of ten patients. This enables the operator to assess the data and to perform verifications or complementary tests if necessary. All results outside a predetermined range can be flagged and results can be deleted, modified or added. A patient's previous files can be recalled as the data are archived at the end of the day. A 120 Mb disk can store approximately 130,000 patient files. A daily archive function can print the day's work in alphabetical order. A communication protocol allows connection to a mainframe computer. This program and the user's manual are available on request, free of charge, from the authors.

Autoanalysis↗
PubMed1994

A new chronometric assay to determine plasma antifactor Xa activity which is insensitive to the antithrombin activity of low molecular weight heparins.

Some commercially available chronometric assays are influenced by the residual antithrombin activity of low molecular weight heparins (LMWH) and they underestimate the ex vivo anti Xa activity. We have evaluated a new kit (Staclot-Heparin) highly specific for the anti Xa activity of LMWH. A comparison with the results given by a reference chromogenic method (Stachrom-Heparin) indicates a very good correlation between the 2 assays (r = 0.95, n = 59). This new assay is not influenced by vitamin K antagonist treatments. Clinical biologists now have the possibility of determining the anti Xa activity generated by LMWH easily and accurately, using a chronometric assay.

Antibodies↗
PubMed1993

Plasma fibrinogen and physiological aging.

Results of prospective studies indicate that increased fibrinogen concentration is significantly associated with the risk of arteriosclerotic vessel disease. As the fibrinogen concentration is considered to rise with aging, determination of its physiological values with various methods in strictly healthy adult and aged individuals is a prerequisite to evaluating the relative contribution of fibrinogen to cardiovascular diseases. Fibrinogen concentration was determined in 209 healthy subjects, aged 19 to 96 years. Persons over the age of 60 were recruited according to the stringent criteria of the Senieur protocol established for human immunogerontological studies. Fibrinogen concentrations, obtained by heating precipitation and by thrombin clotting time with both electromagnetic water-bath and semiautomatic coagulometer, ranged from 1.55 to 3.70 g/L. A rise in plasma concentration was observed with aging. Independently of age, females exhibited higher concentrations than males. Significantly higher values were observed in subjects over 60 years of age, in both sexes, in comparison with the younger groups.

Adult↗
PubMed1991

Discovery of unsuspected pathological states using a new haematology analyser.

A new haematology analyser--the Sysmex NE-8000--provides among other results a bi-dimensional representation of leucocyte populations. Unusual patterns are frequently observed due to platelet aggregation or fibrin polymerisation, and a specific 'rocket-shaped' pattern is also sometimes noted. During a seven month period of routine use 68 such cases were investigated, revealing that this pattern is associated with either severe hepatic dysfunction responsible for patient admission or with various asymptomatic constitutional haemoglobin anomalies. This 'rocket' phenomenon is probably due to incomplete erythrocyte lysis in the leucocyte detector. In some cases it causes spurious leucocyte counting (avoidable by a 1 in 5 pre-dilution of the sample), and alteration of the differential count. To take advantage of this aberrant pattern and to orientate immediate complementary investigations on the basis only of the NE-8000 results, we established a discriminative index.

Adult↗
PubMed1990

[Recurrent thromboembolism disclosing protein C deficiency. Apropos of a case with familial investigation].

Every thromboembolic manifestation, especially in young subjects, calls for an aetiological study in which haemostasis is evaluated primarily with assays of physiological coagulation inhibitors: protein C, protein S and antithrombin III. Protein C deficiency is found in 6 to 7% of thromboembolic manifestations. We report the case of a 21-year old man who had phlebitis followed by pulmonary embolism without facilitating factors. Protein C level was 50% of normal value (0.50 IU/ml). The patient received heparin, subsequently replaced by oral anticoagulants after a long period of overlap between the two treatments. The outcome was favourable. Family investigation yielded a history of thromboembolic accidents in several members of the family, some of whom were protein C deficient (50% of normal value). Protein C synthesis is vitamin K-dependent. Protein C deficiency is transmitted as an autosomal dominant trait. Normal values range from 0.65 to 1.35 IU/ml. Clinically, 25% of the patients are said to be asymptomatic. The first thrombotic accidents occur in young subjects (mean age 29 +/- 14 years). Several points emerge from this case: full evaluation must be performed, especially in young subjects; family investigation consolidates the diagnosis and enables symptomatic protein C deficient patients to be treated and thrombotic manifestations to be prevented by effective anticoagulant therapy in high-risk situations; a prolonged period of heparin-oral anticoagulant overlap is needed to avoid cutaneous necrosis.

Adult↗
PubMed1985

[Evaluation of the performance of an automatic coagulation tester: the Electra 700].

The Electra 700, an automatic coagulation tester recently available in France, was investigated for its performance on routine tests: Quick's test, APTT, thrombin clotting time test, assay of fibrinogen and prothrombin complex factors. Reproducibility was exceptionally good for Quick's test (CV less than 1%), excellent for the other tests (CV less than 3%), acceptability of the various commercial reagents very good, and standard linearity excellent. There was close correlation with manually obtained (electromagnetic B.M.) or semiautomated (KC 10) results (0.9948 to 0.9345). The apparatus is entirely automatic once specimens have been loaded, and it is particularly adapted to dealing with long series of specimens (60 samples). Its original loading system makes it possible to carry out two types of test concurrently, as well as to insert emergency tests. Economically, the cost of disposables and "reagent loss" is satisfactory; however, all tests are carried out relatively slowly, though this is compensated for by the fact that the reactions are completely automatic.

Blood Coagulation Tests↗