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J van Loon

Publications and source records attributed to J van Loon.

At least 19 recordsLinked to original sources
PubMed2002

Effect of enrofloxacin treatment on plasma endotoxin during bovine Escherichia coli mastitis.

OBJECTIVE AND DESIGN: To investigate the effect of enrofloxacin on endotoxin resorption during bovine Escherichia coli mastitis. ANIMALS: 12 healthy early post partum Holstein cows. TREATMENT: Mastitis was induced by intramammary infusion of 10(4) cfu E. coli P4:032. Six cows were treated twice according to the usual enrofloxacin therapy: 5 mg/kg enrofloxacin 1) intravenously at 10 h and 2) subcutaneously at 30 h after challenge. The other 6 cows served as non-treated controls. METHODS: Blood and milk samples were collected at several time points after challenge. LPS in plasma was quantified using the limulus amoebocyte lysate (LAL) assay. The somatic cell count (SCC) and cfu of milk samples were also analysed. RESULTS: Occasional LPS peaks were detected in the plasma of 2 control cows at 6 h post-challenge and of 1 enrofloxacin-treated cow at 10 h post-challenge (P < 0.01 and P < 0.05, respectively, in comparison with time 0), just before enrofloxacin treatment. After enrofloxacin treatment, no significant LPS amounts were detected in the plasma of treated cows, but neither in the control cows. CONCLUSION: During induced coliform mastitis, LPS resorption in plasma occured only sporadically and within 10 h post-challenge. Whereas enrofloxacin treatment clearly limited bacterial growth in milk, significant effects on LPS resorption could not be detected. This suggests that enrofloxacin treatment of E. coli mastitis is predominantly beneficial by its bactericidal activity and is not associated with enhanced resorption of endotoxins.

Animals↗
PubMed2002

Challenging behaviour: a challenge to change.

People with intellectual disability often exhibit severe behavioural problems. Treatment of these problems is frequently very difficult. In The Netherlands, parents, institutes, schools and others can request the services of an independent advisory team with a pool of professionals who have experience with individuals who exhibit challenging behaviour. In this article the methods of the team will be described using a 24-year-old man as an example. The process took almost 7 years. Finally, this man, who had been living full time in one room in total isolation from the rest of the world, fulfilled his heart's desire--visiting the UK by Hovercraft.

Adult↗
PubMed2001

Derivated fetal haemoglobin as a marker for red cell age in the human fetus reflecting stimulated or impaired red blood cell production.

We have determined whether derivated fetal haemoglobin (dHbF, consisting of glycated and acetylated HbF) can be used as a cell age marker for fetal red blood cells (RBCs). Cord blood was obtained between 19 and 39 weeks of gestation from 28 alloimmunised anaemic fetuses (23 RhD+ and 5 Kell) and from 20 non-anaemic fetuses and newborns (controls). Density gradient centrifugation was applied to 36 samples (20 RhD+, 15 controls and 1 Kell) to obtain fractions of increasing cell age. Blood samples were used for measurements of mean cellular volume (MCV), mean cell haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), pyruvate kinase activity (PK) and derivated fetal haemoglobin (dHbF) by cation-exchange HPLC. Reticulocytes were counted only in the whole blood samples. In all density gradient separated RBC fractions, the values for MCV, MCH and PK activity decreased and those of MCHC and dHbF increased with increasing density (equivalent to increasing cell age). The mean density was lower for RBCs of the anaemic RHD group (1.072+/-0.007 g/ml) than for the non-anaemic controls (1.077+/-0.005 g/ml) (p<0.05) The RBC density of the Kell sensitised fetus did not differ from those of the controls. In the control group, the values of the cell age markers in whole blood changed significantly with the gestational age, showing an increase of mean age of the erythrocyte population. The best linear relationship was found for dHbF (y=6.28+0.17*weeks; r=0.84; p<0.001). In the anaemic RhD+ fetuses, the RBC age markers did not change with gestational age; the dHbF percentages were lower, and the MCV, MCH, PK values and the reticulocyte counts were higher than in the controls (0.05<p<0.001). The dHbF values of the Kell sensitised fetuses were above (p<0.01) and the reticulocyte counts were below normal (p<0.05) for gestational age. For the anaemic fetuses, a significant number of the dHbF values (86%) and of the reticulocyte counts (78%) differed from the values of the controls (p<0.01). The dHbF percentages in RhD+ fetuses showed the best correlation with the Hb deficit, which is a measure for anaemia (r=-0.81, p<0.0001). We conclude that the percentage derivated HbF may indicate whether the RBC production is normal for gestational age. It may in that sense reflect stimulated or impaired erythropoiesis in alloimmunised haemolytic anaemia.

Anemia, Hemolytic↗
PubMed2001

Imaging characteristics of noncontained migrating disc fragment and cyst.

The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma.

Adult↗
PubMed2001

The cost-effectiveness of IVF in the UK: a comparison of three gonadotrophin treatments.

BACKGROUND: The objective of this study was to evaluate the cost-effectiveness of women undergoing IVF treatment with recombinant FSH (rFSH) in comparison with highly purified urinary FSH (uFSH-HP) and human menopausal gonadotrophins (HMG). METHODS: A decision-analytic model was used to estimate cost-effectiveness ratios for 'the average cost per ongoing pregnancy' and 'incremental cost per additional pregnancy' for women entering into IVF treatment for a maximum of three cycles. The model was constructed based on a previously published large prospective randomized clinical trial comparing rFSH and uFSH-HP. Where necessary, these data were augmented with a combination of expert opinion, evidence from the literature and observational data relating to the management and cost of IVF treatment in the UK. The cost of rFSH, uFSH-HP and HMG were obtained from National Health Service list prices in the UK. RESULTS: The model predicted a cumulative pregnancy rate after three cycles of 57.1% for rFSH and 44.4% for both uFSH-HP and HMG. The cost of IVF treatment was 5135 pounds sterling for rFSH, 4806 pounds sterling for uFSH-HP and 4202 pounds sterling for HMG. When assessed in association with outcomes, the average cost per ongoing pregnancy was more favourable with rFSH (8992 pounds sterling) than with either uFSH-HP (10 834 pounds sterling) or HMG (9472 pounds sterling). The incremental cost per additional pregnancy was 2583 pounds sterling using rFSH instead of uFSH-HP and 7321 pounds sterling using rFSH instead of HMG. These results were robust to changes in the baseline assumptions of the model. CONCLUSION: rFSH is a cost-effective treatment strategy in ovulation induction prior to IVF.

Cost-Benefit Analysis↗
PubMed2000

Endotoxin, cytokines, and procalcitonin in febrile patients admitted to the hospital: identification of subjects at high risk of mortality.

We prospectively examined 464 febrile patients (median age, 61 years) for predictors of in-hospital death, by use of univariate and multivariate logistic regression using clinical data (age, underlying disease, duration of fever, chills, and shock on admission) and plasma endotoxin, TNF-alpha, IL-6, IL-10, and procalcitonin levels. The mortality rate was 4.6-fold higher (95% confidence interval [CI], 1.8-12) in 31 patients with shock on admission, 7 of whom died; the strongest association with mortality was the endotoxin concentration (relative risk, 13.7; 95% CI, 1. 4-136), which predicted 5 of the deaths with a 5% false-positive rate. For 433 patients without shock on admission, mortality (26 deaths) was associated with age and underlying disease: clinical data predicted 30% of the deaths, whereas IL-6 and procalcitonin levels identified an extra 10% with a 5% false-positive rate. When febrile patients are screened on hospital admission to identify those with a high risk for mortality, clinical judgment on the basis of age, underlying disease, and recent history outweighs the predictive value of endotoxin, cytokine, and procalcitonin levels. Only in patients who present with shock will measurement of endotoxin levels help predict those who will likely die at the cost of few false-positive results.

Adolescent↗
PubMed2000

Posterior fossa decompression in syringomyelia associated with a Chiari malformation: a retrospective analysis of 22 patients.

BACKGROUND: The technique of posterior fossa decompression, nowadays preferred by most neurosurgeons as the first surgical option in the treatment of hindbrain associated syringomyelia, was reintroduced in our center in 1989. We present a retrospective analysis of 22 patients with this pathology who underwent the procedure since then. METHODS: In all patients diagnosis was made by MRI of the craniospinal junction. The operation consisted of a suboccipital craniectomy, removal of the posterior arc of C1, laminectomy of C2 or C3 when necessary and a wide duraplasty at the end. The intradural manipulations (opening of the arachnoid membrane, coagulation or resection of the tonsils) were not uniform. Postoperatively short- and long-term clinical outcome and MRI findings were assessed. RESULTS: Sixteen out of 21 patients (76%) experienced an improvement in the early follow-up period. In the late follow-up period 13 out of 19 patients (68%) were improved, whereas five patients (26%) experienced a marked deterioration. There was no unequivocal effect on all symptoms and signs. Postoperative MR images showed a favorable result in 16 out of 20 patients (80%), consisting of syrinx collapse or reduction of the syrinx diameter. CONCLUSIONS: We conclude that decompression of the posterior fossa is a safe procedure with a considerable chance of clinical improvement. Although total syrinx collapse is not as frequently seen as in syrinx shunting procedures, the clinical outcome may be better. Moreover, there seemed to be no unequivocal correlation between clinical outcome and postoperative syrinx size in the present study.

Adolescent↗
PubMed2000

Endovascular treatment of a ruptured paraclinoid aneurysm of the carotid syphon achieved using endovascular stent and endosaccular coil placement.

We herein report a case of a ruptured superior hypophyseal aneurysm of the left supraclinoid carotid artery that could not be treated with a Guglielmi detachable coil (GDC), even in combination with a supporting nondetachable balloon. After an unsuccessful attempt at surgical clipping, treatment consisted of the placement of a stent over the neck of the aneurysm, advancement of a microcatheter through the stent mesh, and endosaccular embolization with a GDC. The late clinical outcome was excellent.

Aneurysm↗
PubMed1998

The high alkaline fraction on isoelectric focusing of cerebrospinal fluid is cystatin C.

A high alkaline fraction with a pI of 9.2 is sometimes seen on isoelectric focusing patterns of cerebrospinal fluid. The appearance of this fraction mainly depends on the type of concentrators used to prepare the cerebrospinal fluid samples, prior to isoelectric focusing. The amino acid sequence of the high alkaline fraction showed sequence identity to cystatin C, a cysteine protease inhibitor with a pI of 9.2-9.3 and a molecular mass of 13.4 kDa. In addition, on Western blot the high alkaline fraction was recognized by an antibody, directed against cystatin C. Taken together, the present findings demonstrate that the high alkaline fraction is cystatin C.

Amino Acid Sequence↗
PubMed1997

Biocompatibility: the latest developments.

The standards for biological evaluation of medical devices are currently being evaluated. This article presents the rationale behind the current ISO 10993 series and discusses the work in progress to revise elements of the standards and to incorporate new areas. Particular issues being addressed include a new definition of biocompatibility, and quality of health, which will include product risk assessment and surveillance in the market place.

Biocompatible Materials↗
PubMed1995

Long-term results after anterior cervical fusion and osteosynthetic stabilization for fractures and/or dislocations of the cervical spine.

This study presents the 5-9-year follow-up after anterior cervical fusion and osteosynthetic stabilization anterior plating for fractures and/or dislocations of the cervical spine in 25 patients. Adequate bony fusion was obtained in all patients within 1 year postoperatively. There were no problems of late screw loosening. Fracture of the osteosynthetic plate occurred in one patient. Late degenerative changes of the cervical spine at the disc levels adjacent to the fusion area were radiologically detected in 15 of the 25 patients (60%) and were related to the following situations: fusion on more than one disc level, fusion on a lower cervical segment, Frankel class A-C at admission, and hyperflexion injuries. However, these late degenerative changes had no subjective or clinical repercussions, at least until now. From a neurological point of view all patients remained stable postoperatively and no patients had late deterioration.

Adolescent↗
PubMed1994

Muscle- and pneumatic-powered counterpulsating LVADs: a pilot study.

There is a worldwide interest in supporting the failing heart with a skeletal muscle by either wrapping it around the natural heart (dynamic cardiomyoplasty) or by constructing a skeletal muscle ventricle (SMV) used for counterpulsation. Conventional cardiomyoplasty in many clinics carries an operative mortality rate of 15-20% partly because it requires 6 weeks to train the muscle to contract continually. A flexible, pear-shaped blood pump with an inflatable air chamber was designed and made around which a muscle can be wrapped. The advantage of our design is that it can also be driven by pneumatic power, immediately supporting the circulation of a seriously ill patient while that patient is still on the operating table. After a period of time to allow for revascularization and the subsequent training of the muscle, the external pneumatic power can be gradually discontinued. Then the assisted patient becomes tether-free. If, at any time, the muscle power fails, the pneumatic-powered mechanism can be reactivated. In the preferred approach, the blood pump is connected to the aorta for diastolic counterpulsation. A muscle can either be wrapped around the blood pump directly, or around one of two separate muscle pouches connected to the blood pump. To facilitate surgery, a large pouch is inserted under the musculus latissimus dorsi, which is connected to a blood pump. When stimulated, the muscle will contract over the pouch compressing it and providing power to the blood pump. If it is found that the pressure generated in the pouch cannot meet the aortic blood pressure, it can be augmented by using a pressure amplifier.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Controversies in the management of spontaneous cerebellar haemorrhage. A consecutive series of 49 cases and review of the literature.

We have reviewed our experience with a series of 49 consecutive patients with spontaneous cerebellar haematoma, treated according to a standardized management protocol. Seventeen patients were managed conservatively, 30 underwent ventricular drainage, and in six patients the haematoma was evacuated. The indications for the different modes of treatment are discussed. The most significant prognostic factors determining the outcome at one month were the grade of quadrigeminal cistern obliteration on the initial CT scan and the Glasgow Coma Scale on admission. Patients with normal cisterns had a good outcome, and only needed (temporary) ventricular drainage in case of hydrocephalus. Patients with totally obliterated cisterns had a bad outcome irrespective of treatment. In the patients with compressed cisterns, it is suggested that evacuation of the haematoma might improve outcome; treatment of hydrocephalus alone is insufficient in many cases in this group.

Adolescent↗
PubMed1993

Catecholamine response to a gradual increase of intracranial pressure.

To determine the catecholamine response to progressive intracranial hypertension, intracranial pressure (ICP) was raised gradually by continuous expansion of an epidural balloon in seven dogs. Hemodynamic parameters, ICP, and cerebral perfusion pressure (CPP) were monitored continuously and serum catecholamine levels began to rise when CPP was in the low-positive range (20 to 30 mm Hg), reaching a peak just after brain death (CPP < or = o mm Hg). There was no correlation between ICP and the catecholamine peak. Compared to control values, the mean increase was 286-fold for epinephrine and 78-fold for norepinephrine. Temporally, the catecholamine peak corresponded well with the observed hemodynamic changes. These results suggest that ischemia in certain parts of the brain stem is responsible for the hemodynamic changes observed in intracranial hypertension (such as the Cushing response), and they show that catecholamines play an important role in these hemodynamic changes.

Animals↗
PubMed1992

Subcortical aphasia from a thalamic abscess.

A patient is reported who was treated successfully for a left thalamic abscess that resulted in subcortical aphasia. A SPECT scan showed large areas of hypoperfusion in the cortex of the left hemisphere. At follow up after seven months there was marked improvement in the language disorder and the cortical hypoperfusion. It is suggested that aphasia in patients with subcortical lesions results from secondary cortical dysfunctions. The evidence is confined to patients with stroke lesions. The possible implications of this case on current theories of pathophysiological mechanisms, in particular the ischaemic penumbra theory and the cortical diaschisis theory, are briefly discussed. Cortical diaschisis may be the appropriate explanation in this patient.

Adult↗