Search PubMed⌕ Search

Biomedical subjects

J J Hoffmann

Publications and source records attributed to J J Hoffmann.

At least 55 records · Page 3Linked to original sources
PubMed1992

Improved flow cytometric method for HLA-B27 typing.

HLA-B27 is a cell marker of clinical interest because of its high association with certain diseases. The HLA-B27 antigen was detected on lymphocytes using a monoclonal antibody in an indirect immuno-fluorescence assay using a fluorescence flow cytometer. The considerable crossreaction of the monoclonal antibody with the HLA-B7 antigen was effectively suppressed by masking it by means of human anti-HLA-B7 antiserum. The flow cytometric method was evaluated by comparing the results with those obtained by the standard lymphocytotoxicity test and showed complete agreement in 107 selected patient samples.

Cross Reactions↗
PubMed1992

Haemostatic effects in vivo after snakebite by the red-necked keelback (Rhabdophis subminiatus).

We describe a patient who developed a severe coagulopathy after being bitten by a red-necked keelback snake (Rhabdophis subminiatus), a species which is generally considered non-venomous. The patient's blood was incoagulable due to complete depletion of fibrinogen. Comprehensive coagulation studies were performed to identify the mechanism(s) by which the snake toxin caused the coagulopathy. It was found to contain a potent prothrombin activator, probably an activator of protein C and possibly also a factor X activating enzyme. The fibrinolysis was secondary to intravascular fibrin formation; there were no indications for a direct fibrinogenolytic activity in the snake toxin. Remarkably, there was virtually no consumption of antithrombin III, despite extensive thrombin formation; this feature appears to be not uncommon after snake bites, but is still unexplained.

Blood Coagulation Disorders↗
PubMed1992

[Auditory evoked potentials and tumor of the cerebellopontine angle].

The technique of auditory evoked potentials evaluates the auditory pathways along the vestibulocochlear nerve and in the brainstem. The authors stress the importance of this examination in the diagnosis of tumours of the cerebellopontine angle and they discuss its place in relation to radiological investigations.

Cerebellar Neoplasms↗
PubMed1991

[Neonatal blood group incompatibility due to anti-M antibodies].

Neonatal blood group antagonism due to anti-M antibodies is extremely rare. The case is reported of a neonate with moderately severe haemolytic anaemia due to anti-M which required two blood transfusions. Although anti-M antibodies are as a rule regarded as clinically irrelevant, and although they react almost exclusively at lower temperatures, they may in exceptional cases be demonstrated at 37 degrees C, as in the patient described; they may then cause haemolysis. Most strikingly, the direct Coombs test in this patient was negative; this phenomenon has been described before. In unexplained haemolytic anaemia of a newborn, even in the presence of a negative direct Coombs test, the possibility of blood group antagonism should be considered.

Anemia, Hemolytic, Congenital↗
PubMed1991

Histidine-rich glycoprotein in thrombolytic therapy: has it clinical relevance?

The plasma concentrations of histidine-rich glycoprotein and plasminogen were measured and those of free plasminogen calculated in 34 patients with acute myocardial infarction treated with thrombolytic drugs. We investigated whether the plasma levels of histidine-rich glycoprotein and free plasminogen were associated with clinical parameters such as the occurrence and time of successful reperfusion, the incidence of reocclusion and the presence and extent of the systemic lytic state. The mean (+/- SD) pretreatment concentration of histidine-rich glycoprotein was 1.08 +/- 0.24 U/ml, which was almost identical with the normal reference values. After thrombolysis, the mean level decreased slightly. We found no support for a role of these proteins in achieving therapeutic success and only a faint suggestion that histidine-rich glycoprotein might contribute to reocclusion. Surprisingly, the non- or only limited occurrence of systemic lytic state appeared to be associated with a low level of histidine-rich glycoprotein, instead of the high level expected on theoretical grounds. It is therefore unlikely that histidine-rich glycoprotein is of clinical relevance for thrombolytic therapy of acute myocardial infarction.

Anistreplase↗
PubMed1991

Prevention of in vitro fibrinogenolysis during laboratory monitoring of thrombolytic therapy with streptokinase or APSAC.

In the present study, we systematically investigated aprotinin, epsilon-aminocaproic acid (EACA) and tranexamic acid as inhibitors of fibrinogen breakdown and of the generation of fibrinogen degradation products (FgDP). The experimental setting very closely imitated the conditions in practice when collecting blood from patients receiving thrombolytic therapy with streptokinase or APSAC. The minimal concentration of aprotinin required to completely inhibit fibrinogen breakdown and FgDP generation was 200 KIU/ml blood. This was sufficient even at the highest concentrations of streptokinase and APSAC expected to occur in patients (300 U/ml and 46 nM, respectively). However, 200 KIU/ml aprotinin heavily interfered in the determinations of plasminogen and alpha 2-antiplasmin. Relatively low concentrations of EACA (200 mM) and tranexamic acid (35 mM) were sufficient to prevent FgDP generation, but they interfered in the Clauss assay of fibrinogen. A non-interfering concentration of EACA (7 mM) allowed the inhibition of lower concentrations of APSAC (20 nM) and streptokinase. We conclude that at least 200 KIU aprotinin per ml blood is necessary to effectively inhibit in vitro fibrinogenolysis under circumstances likely to be met in clinical practice during thrombolytic therapy.

Aminocaproic Acid↗
PubMed1991

Severe coagulopathy after a bite from a 'harmless' snake (Rhabdophis subminiatus).

European physicians may occasionally be confronted with cases of snake venom poisoning. The increasing interest in snakes as pets has unfortunately resulted in the importation of a number of venomous snakes. We here report the third known case in the medical literature of a patient who was exposed to severe coagulopathy after being bitten by a 'harmless' ringsnake (Rhabdophis subminiatus). The prolonged bleeding diathesis and the complete depletion of fibrinogen observed in our patient are consistent with the presence of a factor X activator in the venom, as has been described in a murine model. In agreement with the two previous case reports, we found no evidence of severe organ damage, despite active intravascular coagulation.

Adult↗
PubMed1991

Diagnostic utility of the pre-incubated acidified glycerol lysis test in haemolytic and non-haemolytic anaemias.

The usefulness of the pre-incubated acidified glycerol lysis test (AGLT), a laboratory test for spherocytosis, has been investigated in a selected hospital population of 348 patients with haemolytic and non-haemolytic anaemia. The AGLT was positive in 58 out of 59 patients with hereditary spherocytosis. In all 32 patients with other types of hereditary haemolytic anaemia the AGLT was normal or equivocal, but clearly different from spherocytosis. Adults with a positive AGLT, but without hereditary spherocytosis, had auto-immune haemolytic anaemia, myelodysplastic syndrome or were pregnant women. In newborn infants the AGLT was positive, in the first week of life, in those babies having hereditary spherocytosis or immune haemolysis due to blood group incompatibility; no positive AGLT results were seen if no haematological explanation for neonatal hyperbilirubinaemia could be found. At the optimal cut-off point the sensitivity of the AGLT for hereditary spherocytosis was 98.3% and the specificity 91.1%, under the most unfavourable conditions. The AGLT is a very useful and simple test for the diagnosis of hereditary spherocytosis.

Adult↗
PubMed1990

Blood viscosity and platelet function in thrombolytic therapy of acute myocardial infarction.

The mechanisms by which thrombolytic drugs accomplish their impressive clinical effects in the treatment of acute myocardial infarction are as yet incompletely appreciated. Factors other than lysis of thrombi and restoration of blood flow most likely play a role, and blood viscosity and platelet function probably are important factors. Blood viscosity is inversely related to oxygen supply to myocardial tissue and therefore a decrease in viscosity might contribute to preservation of myocardial function. Since fibrinogen is a major determinant of blood viscosity and this protein is largely degraded by some thrombolytic drugs, it is conceivable that a systemic fibrinogenolytic state is of additional benefit for the patient. Fibrinogen and other plasma proteins which change during thrombolytic therapy are also essential for adequate platelet function. Besides, thrombolytic drugs can directly affect platelet activity. Although the exact effects are still unknown, it is certain that changes in platelet function induced by thrombolytic drugs are important for the clinical efficacy and probably for the side-effects of thrombolytic therapy.

Anistreplase↗
PubMed1990

A new, low-incidence red cell antigen (HOFM), associated with depressed C antigen.

A case of mild hemolytic disease of the newborn is presented which was caused by an antibody to a hitherto unknown antigen of low incidence. This antigen, now designated as HOFM (ISBT number 700050) was detected in 6 relatives, and in all of them, it was associated with an unusually weakened expression of C antigen. The serological data indicate that HOFM may be part of the Rh system, but the genetic data, although supportive of this interpretation, are inconclusive.

Adult↗
PubMed1988

Comparison of acidified glycerol lysis test, Pink test and osmotic fragility test in hereditary spherocytosis: effect of incubation.

In this study we compared the results of the acidified glycerol lysis test, the Pink test and the osmotic fragility test in 38 patients with hereditary spherocytosis and in healthy controls. The sensitivity of the acidified glycerol lysis test was 81.6% when performed within 3 h after blood collection. After incubating for 24 h, the sensitivity increased to 100% whereas the specificity remained maximal. Similar incubation did not improve the diagnostic utility of the Pink test. All patients, but none of the controls, showed a positive osmotic fragility test. It is concluded, because of sensitivity and specificity in this study, that the acidified glycerol lysis test after incubation and the osmotic fragility test are superior to the Pink test in detecting spherocytosis.

Adolescent↗
PubMed1988

Automated nephelometry of fibrinogen: analytical performance and observations during thrombolytic therapy.

We evaluated the performance of an automated nephelometric determination of fibrinogen, which is an integral part of the prothrombin time assay, in a new coagulation analyzer, the ACL-810 (Instrumentation Laboratory). Results were compared with those by a total clottable protein assay and with the thrombin clotting time assay for fibrinogen. In normal and slightly abnormal plasma, the performance of the ACL method was quite satisfactory (CV 3-10%). However, in abnormal plasma (prolonged prothrombin times because of heparin or oral anticoagulants) the accuracy of the ACL method was poor. Nor could the instrument determine fibrinogen in clearly lipemic plasma. In plasma containing high concentrations of fibrin(ogen) degradation products (FDP), collected during thrombolytic therapy with streptokinase-containing drugs, the ACL method gave spuriously high values for fibrinogen concentration. We determined that this was mainly because of interference by intermediate FDP (fragment Y). Finally, we demonstrated that early FDP (fragment X) increased the ACL results for fibrinogen to the same extent as in the total clottable protein method and that late FDP (fragments D and E) affected the thrombin clotting time method, but not the ACL fibrinogen determination.

Autoanalysis↗
PubMed1987

Plasma prekallikrein activity in patients with total hip arthroplasty.

The behaviour of the contact system was studied in 40 patients with total hip arthroplasty, by measuring plasma prekallikrein, spontaneous kallikrein activity and factor XII. In the literature it had been shown that patients with complications from this operation had decreased prekallikrein and increased kallikrein activity (M. Nakahara. Acta orthop scand 1982; 53:591-6). In the present study, comprising patients with and without pain and proven loosening of the hip prosthesis, these findings could only partially be confirmed. Patients with a loosened prosthesis had significantly lower prekallikrein (mean 0.78 +/- 0.28 U/ml; p less than 0.01) than patients without problems, but no detectable kallikrein activity in plasma. Patients with pain but no loosening had normal prekallikrein (1.04 +/- 0.26 U/ml) and also no demonstrable kallikrein activity. Factor XII was normal in all patient groups. It is concluded that decreased prekallikrein is limited to patients with a loosened hip prosthesis, with or without pain.

Aged↗
PubMed1987

Partial deficiency of eosinophil peroxidase.

A new case of partial eosinophil peroxidase deficiency is reported. It was identified and elaborated using an automated flow-cytochemical analyzer. The findings were confirmed by conventional cytochemistry on blood smears: decreased staining intensity in peroxidase and Sudan Black staining. These results are in agreement with other reports on this extremely rare peroxidase deficiency, which probably is of no clinical relevance.

Child, Preschool↗
PubMed1987

Systemic effects of anisoylated plasminogen streptokinase activator complex and streptokinase therapy in acute myocardial infarction. Coagulation aspects of the Dutch Invasive Reperfusion Study.

The systemic effects of intravenous anisoylated plasminogen streptokinase activator complex (APSAC; 30U) and intracoronary streptokinase (250,000U) were compared in 54 patients with acute myocardial infarction. In 3 patients, no signs of a systemic lytic state were observed. In all other patients, significant reductions of coagulation and fibrinolytic factors occurred: fibrinogen levels decreased by 86% in the APSAC group and 81% in the streptokinase group; for plasminogen the decreases were 68 and 66%, and for alpha 2-antiplasmin activity greater than 95 and 94%, respectively. Fibrin(ogen) degradation products were increased 68- and 38-fold, respectively. Although there was a trend for the lytic state to be more profound in the APSAC-treated patients, there was no difference between treatment groups with regard to bleeding complications or therapeutic efficacy, the latter being 79 and 73%, respectively, for APSAC and streptokinase. Total fibrinolytic activity, measured as euglobulin clot lysis time, was sustained for longer in the APSAC group, which may explain the low reocclusion rate in this group in comparison with the streptokinase group.

Anistreplase↗
PubMed1987

Vascular distribution of plasma catecholamines--pulmonary extraction, arterio-venous differences and effect of age.

In 19 normotensive patients undergoing cardiac catheterization, plasma samples were simultaneously collected from five different sites for measuring adrenaline and noradrenaline concentrations. Mean levels (+/- SEM) in pulmonary artery and aorta were 1.70 +/- 0.13 and 1.76 +/- 0.12 nmol/l for noradrenaline and 0.35 +/- 0.05 and 0.36 +/- 0.05 nmol/l for adrenaline, respectively. Thus, no pulmonary uptake of either catecholamine was demonstrated; this was independent of ventilatory lung function. Significant peripheral extraction was only found for adrenaline, and not for noradrenaline, so we found no evidence for the necessity of arterial blood sampling for noradrenaline determinations in this static study. Finally, a significant positive correlation of venous (r = 0.56; p less than 0.01), but not arterial noradrenaline concentration with age was found, as was a negative correlation of both arterial (r = -0.55; p less than 0.01) and venous (r = -0.62; p less than 0.005) adrenaline concentrations with age. The release of adrenaline by the adrenal glands proved to be significantly decreasing with increasing age (r = -0.53; p less than 0.02).

Adult↗