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Showing papers by "Katholieke Universiteit Leuven published in 1985"


Journal ArticleDOI
TL;DR: In the patients randomised to active treatment there were 29 fewer cardiovascular events and 14 fewer cardiovascular deaths per 1000 patient years during the double-blind part of the trial.

1,328 citations


Journal ArticleDOI
TL;DR: In this article, explicit expressions for general actions of vector and scalar multiplets coupled to N = 2 supergravity are presented, which are based on the superconformal tensor calculus.

677 citations


Journal ArticleDOI
TL;DR: In this paper, the authors tested the effect of belongingness to self as a sufficient condition for the enhancement of the attractiveness of visual letter stimuli and found that, independent of visual, acoustical, aesthetic, semantic and frequency characteristics, letters belonging to own first and/or family name are preferred above not-own name letters.
Abstract: ‘Mere belongingness to self’ is tested as a sufficient condition for the enhancement of the attractiveness of visual letter stimuli. Experimental evidence is presented that, independent of visual, acoustical, aesthetic, semantic and frequency characteristics, letters belonging to own first and/or family name are preferred above not-own name letters. The effect is obtained in the absence of awareness of the Gestalt of any name, thus challenging current understanding of fundamental affective processes.

542 citations


Journal ArticleDOI
TL;DR: The texture analysis methods being used at present are reviewed and statistical as well as structural approaches are included and their performances are compared.
Abstract: In this paper the texture analysis methods being used at present are reviewed. Statistical as well as structural approaches are included and their performances are compared. Concerning the former approach, the gray level difference method, filter mask texture measures, Fourier power spectrum analysis, cooccurrence features, gray level run lengths, autocorrelation features, methods derived from texture models, relative extrema measures, and gray level profiles are discussed. Structural methods which describe texture by its primitives and some placement rules are treated as well. Attention has to be paid to some essential preprocessing steps and to the influence of rotation and scale on the texture analysis methods. Finally the problem of texture segmentation is briefly discussed.

440 citations


Journal ArticleDOI
01 Mar 1985-Drugs
TL;DR: The main indications for tranexamic acid are the prevention of excessive bleeding after tonsillectomy, prostatic surgery, and cervical conisation, and primary and IUD-induced menorrhagia, and the addition of aprotinin seems to decrease the incidence of delayed cerebral vasospasm and ischaemic complications which are sometimes noted when tranExamic acid alone is used.
Abstract: The basic proteinase inhibitor from bovine organs, aprotinin, was first identified in 1930 and its effect on enzyme and other biological systems has since been extensively studied. Aprotinin can only be administered intravenously and has a half-life of about 2 hours. Its administration at the start of cardiopulmonary bypass surgery appears to reduce blood loss and to protect against global myocardial ischaemia. Similarly, a smaller infarct size seems to result from early administration of aprotinin within the first hour after myocardial infarction, though further studies are needed to confirm this effect. A combination of aprotinin with tranexamic acid may be effective in preventing or delaying rebleeding after rupture of an intracerebral aneurysm; the addition of aprotinin seems to decrease the incidence of delayed cerebral vasospasm and ischaemic complications which are sometimes noted when tranexamic acid alone is used. Aprotinin is also effective as adjuvant treatment in traumatic haemorrhagic shock. The recommended loading dose is 15,000 to 20,000 KIU/kg bodyweight administered as a short intravenous infusion, followed by 50,000 KIU/hour by continuous infusion. Side effects of aprotinin are very rare. Epsilon-Aminocaproic acid (EACA), p-aminomethylbenzoic acid (PAMBA) and tranexamic acid are synthetic antifibrinolytic amino acids. Saturation of the lysine binding sites of plasminogen with these inhibitors displaces plasminogen from the fibrin surface. On a molar basis tranexamic acid is at least 7 times more potent that epsilon-aminocaproic acid and twice as potent as p-aminomethylbenzoic acid. All 3 compounds are readily absorbed from the gastrointestinal tract and excreted in active form in the urine. The plasma half-life of tranexamic acid is about 80 minutes. The main indications for tranexamic acid are the prevention of excessive bleeding after tonsillectomy, prostatic surgery, and cervical conisation, and primary and IUD-induced menorrhagia. It is possible that gastric and intestinal bleeding can also be reduced as well as recurrent epistaxis. Tranexamic acid could also be useful after ocular trauma. The value of fibrinolysis inhibitors in the prevention of bleeding after tooth extraction in patients with haemophilia is well documented, as is the treatment of hereditary angioneurotic oedema. The usual dose of tranexamic acid is 0.5 to 1g (10 to 15 mg/kg bodyweight) given intravenously 2 to 3 times daily, or 1 to 1.5 g orally 3 to 4 times daily. This dose needs to be reduced in patients with renal insufficiency. The main side effects of tranexamic acid are nausea or diarrhoea.

414 citations


Journal ArticleDOI
TL;DR: 5q- is the most frequently occurring single chromosome anomaly in secondary leukemia, and the resemblance between de novo and secondary 5q- MDS and ANLL is striking; clinically, as well as cytogenetically, they are indistinguishable, suggesting that all de noVO cases may be due to environmental (chemical) carcinogens.

304 citations


Journal ArticleDOI
TL;DR: In this paper, the incidence of thromboembolic complications was compared retrospectively in 90 cadaveric kidney allograft recipients treated with cyclosporin and low-dose steroids and the same number of CKG recipient treated with azathioprine, antilymphocyte globulin, and high-dose steroid.

295 citations


Journal ArticleDOI
TL;DR: It is demonstrated that in some situations parts of the total cooperation line are achievable and it is proved that if the encoders and the decoder are allowed to be nondeterministic, the capacity regions are not increased.
Abstract: The capacity regions are determined for various communication situations in which one or both encoders for a multiple access channel crib from the other encoder and learn the channel input(s) (to be) emitted by this encoder. Most of the achievability proofs in this paper hinge upon the new concept of backward decoding. Also, the notion of Shannon strategies seems to be of crucial importance. It is demonstrated that in some situations parts of the total cooperation line are achievable. Moreover, it is proved that if the encoders and the decoder are allowed to be nondeterministic, the capacity regions are not increased.

279 citations


Journal ArticleDOI
TL;DR: An expression vector was constructed which directs the synthesis of pro u-PA in E. coli using the plasmid pBR322, and the 5′ region was obtained by priming poly(A) mRNA with a DNA fragment derived from the initial clone.
Abstract: An Escherichia coli library containing cDNA sequences derived from mRNA of human pharnygeal carcinoma cells was constructed using the plasmid pBR322. The library was screened with a set of 8 deoxyoligonucleotides, 14 bases in length, which collectively code for the amino acid sequence …Met-Tyr-Asn-Asp-Pro… found in human urokinase (u-PA). A plasmid containing an ∼1700 base pair cDNA insert coding for the carboxy terminal sequence of u-PA was identified. The 5′ region was obtained by priming poly(A) mRNA with a DNA fragment derived from the initial clone. An expression vector was constructed which directs the synthesis of pro u-PA in E. coli.

240 citations


Journal ArticleDOI
TL;DR: This ELISA with monoclonal antibodies constitutes a stable and reproducible set of reagents for the measurement of t-PA antigen in biological fluids, avoiding the disadvantages of the use of radioisotopes and of polyclonal antibodies.
Abstract: An enzyme-linked immunosorbent assay (ELISA) for the measurement of human tissue-type plasminogen activator (t-PA) was developed. Microtiter plates were coated with a mixture of two monoclonal antibodies and bound t-PA was quantitated with a third monoclonal antibody linked to peroxidase. The lower limit of sensitivity of the assay was 0.2 ng of t-PA per ml. The concentration of antigen in citrated plasma of human subjects was found to be 3.4 +/- 0.8 ng/ml. The assay had a good reproducibility with values of 3.8, 6.5 and 4.9 percent respectively for the intra-, inter-assay and inter-dilution variation coefficients. The results of the ELISA assay on plasma samples from patients during thrombolytic therapy with t-PA correlated very well, over a wide concentration range, with those obtained with a previously described two-site immuno-radiometric assay (r = 0.96). This ELISA with monoclonal antibodies constitutes a stable and reproducible set of reagents for the measurement of t-PA antigen in biological fluids, avoiding the disadvantages of the use of radioisotopes and of polyclonal antibodies.

219 citations


Journal ArticleDOI
TL;DR: An analysis of clinical, haematological, histological and cytogenetic data was performed in 85 consecutive patients with myelodysplastic syndromes, finding that patients with refractory anaemia and AISA had a lower incidence of evolution to AML, but a higher mortality rate from infections and/or bleeding.
Abstract: An analysis of clinical, haematological, histological and cytogenetic data was performed in 85 consecutive patients with myelodysplastic syndromes (MDS). The criteria for diagnosis of refractory anaemia (RA), acquired idiopathic sideroblastic anaemia (AISA) and chronic myelomonocytic leukaemia (CMML) were clearly defined, since the inclusion criteria provided by the FAB co-operative group are imprecise. None of these patients has received chemotherapy during the follow-up period. The median survival of the whole group was only 15 months, with less than 10% of the patients surviving after 5 years. Fifteen patients (17.6%) were still alive at time of analysis, 31 (36.5%) have developed acute myeloid leukaemia (AML) and only one of them is still alive; 30 (35.3%) died of infectious and/or haemorrhagic complications. Patients who developed AML had a shorter survival (median survival time 9.5 versus 15 months) but this difference was not significant (P = 0.10). Factors with prognostic value are in order of significance: abnormal localized immature myeloid precursors (= ALIP) in the trephine biopsy, circulating myeloblasts, excess of blasts in the bone marrow smears, age, FAB classification and granulocyte count. In comparison to refractory anaemia with excess of blasts (RAEB), CMML and RAEB in transformation (RAEBt), patients with RA and AISA had a lower incidence of evolution to AML (11% versus 56%), but a higher mortality rate from infections and/or bleeding (59.2% versus 29%). ALIP negative cases were only found among patients with RA and AISA, whereas ALIP positivity was observed in all cases of RAEB and RAEBt, in 10/11 patients with CMML and in almost half the cases of RA and AISA. In RA and AISA patients survival was significantly different between ALIP positive and ALIP negative cases (P = 0.009). Among MDS patients, ALIP negative cases developed significantly less AML than ALIP positive cases (5% versus 44%), but a similar percentage of mortality from infectious and/or haemorrhagic complications was seen in both groups (33% versus 36.5%). Chromosomal analysis proved to be of no significant prognostic value, although a trend for shorter survival was observed in patients with complex karyotype anomalies or without mitoses. Because of their prolonged survival, antileukaemic chemotherapy is contra-indicated in ALIP negative patients (median survival 50 months). Nevertheless they only constitute a minor subgroup of MDS cases. Prognosis in ALIP positive patients is poor (median survival 12.5 months); in these patients therapeutic trials with cytostatic drugs or with inducers of differentiation of myeloid precursor cells seem to be justified.

Journal ArticleDOI
01 Jan 1985-Nature
TL;DR: The complete purification and partial sequencing of the 22K factor are reported, finding that the amino-acid sequence of this factor is at least partially homologous to a complementary DNA-derived IL-1 sequence, and it is postulate that the 23K factor also belongs to theIL-1 family.
Abstract: In vitro stimulation of mononuclear cells from human peripheral blood with mitogens causes the release of factors (monokines and lymphokines) which possess distinct biological activities. One such factor, termed 22K, can induce production of human beta-interferon (HuIFN-beta) in cultured human fibroblasts, thereby rendering these cells resistant to virus infection. Here we report the complete purification and partial sequencing (39 N-terminal amino acids) of this factor, whose relative molecular mass was estimated by SDS-polyacrylamide gel electrophoresis to be 17,000 (17K). In addition to an antiviral effect, the pure protein exhibits several other biological activities. Most significantly, intravenous (i.v.) injection of the factor in rabbits caused fever and granulopenia at doses of 0.1-1 microgram per kg, effects which we attribute to a monokine called endogenous pyrogen (EP). In vitro, the protein was scored as positive in a LAF (lymphocyte-activating factor) assay at 0.1-1 ng ml-1. LAF and EP are considered to be members of one family of monokines, called interleukin-1 (IL-1). For this reason, and also because the amino-acid sequence of the 22K factor is at least partially homologous to a complementary DNA-derived IL-1 sequence, we postulate that the 22K factor also belongs to the IL-1 family.

Journal ArticleDOI
TL;DR: These findings suggest that the oblique effect in line orientation has at least two sensorial components, one of which is attributed to the meridional variations in the preferred orientation of area 17 S-cells.

Journal ArticleDOI
TL;DR: In this article, the Akaki River section of the Troodos ophiolite complex was analyzed and the major elements, K, Rb, Cs, Sr, Ba, Sc, Cr, Ni, Hf, Ta, Th, and REE concentrations and isotopic compositions of carefully hand-picked volcanic glasses were reported.

Journal ArticleDOI
TL;DR: A tissue culture technique for rapid clonal propagation and storage under minimal growth conditions is presented and the cultivars tested seem to vary in their ability to withstand minimal growth temperature.
Abstract: A tissue culture technique for rapid clonal propagation and storage under minimal growth conditions is presented in this paper Shoot-tip cultures of Musa cultivars (both banana and plantain) are induced by culturing small excised shoot apices on modified MS semisolid medium supplemented with various concentrations and combinations of auxins and cytokinins The effects of cytokinin concentration in the medium as well as the genotypic configuration of the cultivars on the rate of shoot-bud proliferation have been tested The established shoot-tip cultures grown on modified MS semisolid medium supplemented with IAA (018 mg/l) and BA (230 mg/l) have been successfully stored at 15°C with 1000 lux light intensity up to 13–17 months depending on the cultivar The cultivars tested in the present investigation seem to vary in their ability to withstand minimal growth temperature

Journal ArticleDOI
TL;DR: The observation that a factor that belongs to the IL-1 family induces the 26-kDa-protein suggest that the latter plays a role as an intermediary or effector molecule in inflammatory or immunoregulatory processes.
Abstract: A human-leukocyte-derived antiviral protein (22-kDa factor), known to be an inducer of interferon-β (IFN-β) in fibroblastoid cells, and to be closely related to interleukin-1 (IL-1), was shown to likewise act as inducer of the mRNA of a 26-kDa secreted protein. This protein was first described as the gene product of an mRNA that is co-induced with the mRNA of IFN-β by superinduction of fibroblasts (treatment with dsRNA and cycloheximide). Subsequently it was shown to be induced by treatment with cycloheximide only. The 22-kDa factor induced high levels of the 26-kDa-protein mRNA and low levels of IFN-β mRNA. Addition of cycloheximide to the 22-kDa-factor resulted in further significant increases in mRNA levels for both the 26-kDa-protein and IFN-β. These observations add to the evidence already available that transcription of the genes for IFN-β and the 26-kDa-protein are differently regulated. The observation that a factor that belongs to the IL-1 family induces the 26-kDa-protein suggest that the latter plays a role as an intermediary or effector molecule in inflammatory or immunoregulatory processes.

Journal ArticleDOI
TL;DR: In this paper, a primal partitioning scheme with a network flow subproblem is proposed to minimize the processing costs of a multi-item capacitated lot-sizing problem, based on a Lagrangean relaxation of the capacity constraints imposed on the resources.
Abstract: The multi-item capacitated lot-sizing problem consists of determining the magnitude and the timing of some operations of durable results for several items in a finite number of processing periods so as to satisfy a known demand in each period. The subgradient algorithm implemented to minimize the processing costs is based on a Lagrangean relaxation of the capacity constraints imposed on the resources. The method incorporates a primal partitioning scheme—with a network flow subproblem—to obtain good feasible solutions.

Journal ArticleDOI
TL;DR: Serial morphological and cytogenetic investigations were performed in 46 patients with the myelodysplastic syndrome and Twenty‐one patients (45.5%) progressed to AML.
Abstract: Serial morphological and cytogenetic investigations were performed in 46 patients with the myelodysplastic syndrome (MDS). Twenty-one patients (45.5%) progressed to AML (greater than 30% blasts in bone marrow smears). Based on sequential determinations of percentages of bone marrow blasts, three patterns of evolution were observed in MDS. Patients with evolution pattern A (48%) had an apparently stable disease with minimal or no increase in bone marrow blasts. Exceptionally they developed new or additional chromosomal anomalies during the course of their disease. Cases in this group, who showed no abnormal localization of immature myeloid precursors (ALIP) at time of diagnosis experienced prolonged survival (median: 43 months), while ALIP positive patients had shorter survival times (median: 14 months), with high probability of early death from infections and/or bleeding problems. Patients with evolution pattern B (28%) initially had a morphologically stable disease, comparable to cases with evolution pattern A, but showed an abrupt shift from MDS to AML. Most of these patients (82%) were ALIP positive and a substantial proportion (46%) showed karyotype anomalies at diagnosis. The abrupt shift to AML in these patients was frequently (61.5%) associated with additional cytogenetic anomalies. Patients with evolution pattern C (24%) showed a gradual increase in bone marrow blasts. The majority of these cases (8/11) ultimately developed acute myeloid leukaemia (gradual progression to AML), whereas some patients (3/11) died from infections and/or haemorrhagic complications before they had reached the level of clinical AML. All of these patients were ALIP positive at diagnosis and no additional cytogenetic alterations occurred during evolution. Acquisition of new karyotypic anomalies during the course of MDS was almost invariably associated with abrupt shift to AML. From this retrospective study we conclude that evolution in MDS shows two important aspects, which seem to be preponderant in determining the course and outcome of the disease: one is the proliferative capacity and resulting growth advantage of the neoplastic clone over normal haematopoiesis, as measured by increasing percentages of bone marrow blasts in sequential aspirates; the other one is instability of the clone. Unstable clones have a high propensity to further intraclonal changes; they are expressed morphologically by the abrupt increase in bone marrow blasts and cytogenetically by the acquisition of new or additional karyotype anomalies.(ABSTRACT TRUNCATED AT 400 WORDS)


Journal ArticleDOI
TL;DR: In this paper, a CMOS switched capacitor instrumentation amplifier is presented, where offset is reduced by an auto-zero technique and effects due to charge injection are attenuated by a special amplifier configuration.
Abstract: A CMOS switched capacitor instrumentation amplifier is presented. Offset is reduced by an auto-zero technique and effects due to charge injection are attenuated by a special amplifier configuration. The circuit which is realized in a 4-/spl mu/m double poly process has an offset (/spl tau/) of 370 /spl mu/V, an rms input referred integrated noise (0.5 -f/sub c//2) of 79 /spl mu/V, and consumes only 21 /spl mu/W (f/sub c/ = 8 kHz, V/sub DD/ = 3 V).

Journal ArticleDOI
01 Jan 1985-Catena
TL;DR: In this article, the authors evaluate the transport capacity and the selective transport of thin flows for Tongrian sand and show that the erosive power of a thin flow would increase rapidly once a shear velocity of 3.0-3.5 cm/s is exceeded and this value might be a valuable threshold for the onset of rill erosion.
Abstract: Summary Laboratory experiments were conducted to evaluate the transport capacity and the selective transport of thin flows. The aggregate size as well as the grain size of the eroded and transported loamy materials could best be related to the shear velocity of the flow, whereby it was observed that, when the shear velocity was greater than 3.0–3.5 cm/s, transport and erosion of loamy materials becomes aselective. Sediment concentration however could best be related to the product of mean and shear velocity. The transport capacity of thin flows for a well sorted Tongrian sand (D 50 ≅ 100 μ m) starts rising rapidly at a shear velocity of 3.15 cm/s. It could thus be expected that the erosive power of a thin flow would increase rapidly once a shear velocity of 3.0–3.5 cm/s is exceeded and that this value might be a valuable threshold for the onset of rill erosion. This is confirmed by field observations.

Journal ArticleDOI
TL;DR: The observation that the production of this factor by Sertoli cell cultures is stimulated by FSH and dbcAMP suggests that, in the testis, it may play a role in the paracrine control of Leydig cell function.

Journal ArticleDOI
01 Jan 1985-Nature
TL;DR: In this paper, a new method for the preparation of ionic sodium clusters in zeolites is presented, consisting of the impregnation of a dehydrated zeolite with alcoholic solutions of sodium azide, followed by the controlled decomposition of the azide.
Abstract: Exposure of high-alumina zeolites to sodium metal vapour produces coloured centres1–5 which have been associated with the formation of ionic sodium clusters, located in the zeolite cages. To form these centres, excess alkali metal is required, which contaminates the reaction vessel and makes the system unsuitable as a heterogeneous catalyst. The pioneering work of Pines6 in the area of basic catalysis on sodium metal deposited on alumina implies that ionic clusters in zeolites should exhibit interesting catalytic properties, but there have been no reports of such activity because the procedure yields a material which is difficult to reproduce. Here we present a new method for the preparation of such clusters in zeolites, consisting of the impregnation of a dehydrated zeolite with alcoholic solutions of sodium azide, followed by the controlled decomposition of the azide. As demonstrated by electron-spin resonance (ESR) spectroscopy, ionic sodium clusters are formed in the zeolite pores. These clusters exhibit catalytic properties in both isomerization and hydrogenation reactions of alkenes and alkynes. We believe that this represents the first realistic method for the preparation of alkali metal clusters in zeolites as well as the first catalytic characterization of such systems.


Journal ArticleDOI
TL;DR: Normal values for VAT are determined that can be used for clinical exercise testing in the pediatric age group and a significant decrease was found in boys and girls with age, which suggests an increase in lactacid anaerobic capacity during growth.
Abstract: The ventilatory anaerobic threshold (VAT) during graded exercise was defined as the oxygen uptake (\(\dot V_{{\text{O}}_{\text{2}} }\)) immediately below the exercise intensity at which pulmonary ventilation increased disproportionally relative to \(\dot V_{{\text{O}}_{\text{2}} }\). Since VAT is considered to be a sensitive and noninvasive measure for evaluating cardiorespiratoy endurance performance, the purpose of the present study was to determine normal values in children. We examined 257 healthy children (140 boys and 117 girls) varying in age from 5.7 to 18.5 years, during treadmill exercise. The data were analyzed in relation to sex and age. In boys the lowest \(\dot V_{{\text{O}}_{{\text{2max}}} }\) (ml · min−1 · kg−1) was found in the youngest age group (5–6 year). In girls, on the other hand, no significant increase occurred with age. For VAT, expressed as ml O2 · min−1 · kg−1 or as a percent of \(\dot V_{{\text{O}}_{{\text{2max}}} }\) a significant decrease was found in boys and girls with age. This suggests an increase in lactacid anaerobic capacity during growth. In contrast to observations in adults, only low correlations were found between \(\dot V_{{\text{O}}_{{\text{2max}}} }\) and VAT (r=0.28 in boys and r=0.52 in girls), which suggests that the development of the underlying physiological mechanism does not occur at the same rate in growing children. These data provide normal values for VAT that can be used for clinical exercise testing in the pediatric age group.

Journal ArticleDOI
TL;DR: The findings indicate that the NEB are predominantly innervated by sensory nerve fibers, derived from cell bodies in the nodose ganglion of the vagus nerve, which corroborates the hypothesis that NEB represent intrapulmonary neuroreceptors.

Journal ArticleDOI
TL;DR: In this article, a colourimetric assay based on the reaction of A-rings with the chromogen p-dimethylaminocinna-maldehyde has been developed for flavanoids in beer.
Abstract: A new colourimetric assay (based upon the reaction of their A-rings with the chromogen p-dimethylaminocinna-maldehyde) has been developed for flavanoids in beer. The flavanoid content for 19 different Belgian Pilsner beers by this method varied between 4·8 and 39·5 mg/litre with a mean of 26·3 mg/litre. These results were compared with the analytical data for total polyphenolics (EBC, Singleton), anthocyanogens (Jerumanis), and flavanoids (vanillin procedure). Good correlations existed between the results by the new method and the analytical data for total polyphenolics (EBC) and anthocyanogens (Jerumanis). Analysis by the new assay requires only one reagent and it is clear from the analytical data that the method is highly reproducible and sensitive

Journal ArticleDOI
TL;DR: In this paper, large rolling deformations of b.c. polycrystals and resulting textures are simulated by "full constraint" and "relaxed constraints" Taylor models and several values of the critical shear stress ratio of {112} and {110} slip planes are used.

Journal ArticleDOI
TL;DR: Clinical studies have been initiated assuming a significantly increased tolerance by reduction of fraction size to about 1 Gy, however, in the present experiments no evidence was found for such an increase in tolerance with fraction sizes below 2 Gy.
Abstract: The radiation tolerance of the spinal cord, both in man and in rats, has been shown to depend strongly on the size of the dose per fraction. With fraction doses down to about 2 Gy, the spinal cord tolerance can be predicted by a modified Ellis formula: D approximately N0.43. More recently alternative isoeffect formulas were based on the linear-quadratic (LQ) model of cell survival where the effect of dose fractionation is characterized by the ratio alpha/beta which varies from tissue to tissue. For the spinal cord, as well as for other late responding tissues, the ratio alpha/beta is small, in contrast to most acutely responding tissues. Both the Ellis-type formula, and to a lesser extent the LQ-model, predict a continuously increasing tolerance dose with decreasing fraction size. From the LQ model, the concept of "flexure dose" has been derived, which proposes the limit of effective fractionation to be about 0.1 alpha/beta. At this dose per fraction no significant further gain in tolerance would be detected. From previous experiments on the rat cervical spinal cord with doses per fraction down to about 2 Gy, the ratio alpha/beta was determined to be 1.7 Gy, and the LQ-model would predict a rise in tolerance with a reduction in fraction size to far below 2 Gy. Based on these predictions clinical studies have been initiated assuming a significantly increased tolerance by reduction of fraction size to about 1 Gy. However, in the present experiments no evidence was found for such an increase in tolerance with fraction sizes below 2 Gy.

Journal ArticleDOI
TL;DR: The new system of reporting the level of anticoagulation was designed and can only safely be applied in patients taking oral antICOagulants.
Abstract: One of the reasons why oral anticoagulants fell into disrepute is the absence of internationally accepted standardised procedures for controlling the level of anticoagulation. 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.