Harmonizing light transmission aggregometry in the Netherlands by implementation of the SSC-ISTH guideline.

Light transmission aggregometry (LTA) is considered the gold standard method for evaluation of platelet function. However, there are a lot of variation in protocols (pre-analytical procedures and agonist concentrations) and results. The aim of our study was to establish a national LTA protocol, to investigate the effect of standardization and to define national reference values for LTA. The SSC guideline was used as base for a national procedure. Almost all recommendations of the SSC were followed e.g. no adjustment of PRP, citrate concentration of 109 mM, 21 needle gauge, fasting, resting time for whole blood and PRP, centrifugation time, speed and agonists concentrations. LTA of healthy volunteers was measured in a total of 16 hospitals with 5 hospitals before and after standardization. Results of more than 120 healthy volunteers (maximum aggregation %) were collected, with participating laboratories using 4 different analyzers with different reagents. Use of low agonist concentrations showed high variation before and after standardization, with the exception of collagen. For most high agonist concentrations (ADP, collagen, ristocetin, epinephrine and arachidonic acid) variability in healthy subjects decreased after standardization. We can conclude that a standardized Dutch protocol for LTA, based on the SSC guideline, does not result in smaller variability in healthy volunteers for all agonist concentrations.

Help seeking behavior and onset-to-alarm time in patients with acute stroke: sub-study of the preventive antibiotics in stroke study.

BACKGROUND: Patients with acute stroke often do not seek immediate medical help, which is assumed to be driven by lack of knowledge of stroke symptoms. We explored the process of help seeking behavior in patients with acute stroke, evaluating knowledge about stroke symptoms, socio-demographic and clinical characteristics, and onset-to-alarm time (OAT). METHODS: In a sub-study of the Preventive Antibiotics in Stroke Study (PASS), 161 acute stroke patients were prospectively included in 3 Dutch hospitals. A semi-structured questionnaire was used to assess knowledge, recognition and interpretation of stroke symptoms. With in-depth interviews, response actions and reasons were explored. OAT was recorded and associations with socio-demographic, clinical parameters were assessed. RESULTS: Knowledge about stroke symptoms does not always result in correct recognition of own stroke symptoms, neither into correct interpretation of the situation and subsequent action. In our study population of 161 patients with acute stroke, median OAT was 30 min (interquartile range [IQR] 10-150 min). Recognition of one-sided weakness and/or sensory loss (p = 0.046) and adequate interpretation of the stroke situation (p = 0.003), stroke at daytime (p = 0.002), severe stroke (p = 0.003), calling the emergency telephone number (p = 0.004), and transport by ambulance (p = 0.040) were associated with shorter OAT. CONCLUSION: Help seeking behavior after acute stroke is a complex process. A shorter OAT after stroke is associated with correct recognition of one-sided weakness and/or sensory loss, adequate interpretation of the stroke situation by the patient and stroke characteristics and logistics of stroke care, but not by knowledge of stroke symptoms.

Efficacy of patient selection strategies for carotid endarterectomy by contrast-enhanced MRA on a 1 T machine and duplex ultrasound in a regional hospital.

AIM: To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (DUS) could replace digital subtraction angiography (DSA) for diagnosing internal carotid artery (ICA) stenosis in regional centres with less specialized technicians and equipment, such as a 1 Tesla MRI machine. MATERIALS AND METHODS: Sixty-six consecutive, symptomatic patients with ICA stenosis, as evidenced using DSA, were included. In the first 34 patients DUS was validated and cut-off criteria were established. Data were analysed by receiver operating characteristic curve and logistic regression. Two observers analysed the DUS and CE-MRA results of 32 patients. Stenoses were categorized in accordance with North American Symptomatic Endarterectomy Trial (NASCET) measurement criteria. RESULTS: Peak systolic velocity (PSV) in the ICA was defined as a better parameter for defining stenosis than end diastolic velocity and the PSV ICA:common carotid artery ratio. The optimal PSV threshold was 230cm/s. Four ICAs were not interpretable on DUS, and one on CE-MRA. Two patients did not undergo CE-MRA. The sensitivities and specificities were calculated: for DUS these were 100% and 68% respectively; for observer 1 on CE-MRA these were 93% and 89%, respectively; for observer 2 these were 92% and 87%, respectively. The sensitivity and specificity for combined DUS/CE-MRA were 100% and 85%, respectively. Seventy-eight percent of CE-MRA and DUS correlated. The weighted Kappa for CE-MRA and DSA were 0.8 and 0.9, respectively. CONCLUSION: DUS and CE-MRA are effective non-invasive methods for selecting patients with ICA stenosis for carotid endarterectomy in non-specialized centres using a 1T machine. The present results suggest that no referrals to more specialized centres for non-invasive diagnostic work-up for carotid artery stenoses will be necessary.

Multifocal inflammatory demyelinating neuropathy: a distinct clinical entity?

BACKGROUND: Several patients have been reported with an asymmetric sensory or sensorimotor demyelinating neuropathy not fulfilling the diagnostic criteria for chronic inflammatory demyelinating polyneuropathy or multifocal motor neuropathy. OBJECTIVE: To present the clinical, electrophysiologic, radiologic, and pathologic features of six patients with an asymmetric sensory or sensorimotor demyelinating neuropathy. RESULTS: All six patients were initially affected in only one limb; in four patients the neuropathy progressed to other limbs in an asymmetric fashion during several years. On electrophysiologic examination, evidence of multifocal demyelination and conduction block in motor and sensory nerves was found in all patients. MRI of the brachial plexus revealed swollen nerves and an increased signal intensity on T2-weighted imaging in four patients. A biopsy sample taken from the brachial plexus of one patient revealed evidence of inflammation. All patients showed a beneficial response to IV immunoglobulin treatment. Thirty-four similar patients have been reported previously, many of whom were initially diagnosed as having various other (nontreatable) diseases. CONCLUSIONS: The authors propose calling this neuropathy "multifocal inflammatory demyelinating neuropathy" and considering it as a distinct clinical entity to facilitate early diagnosis of this treatable disorder.

Treatment of multifocal motor neuropathy with high dose intravenous immunoglobulins: a double blind, placebo controlled study.

The effect of high dose intravenous immunoglobulin (IVIg) treatment was studied in six patients with multifocal motor neuropathy (MMN). All patients responded to treatment (0.4 g/kg for five consecutive days) in an open trial. The effect of IVIg treatment was confirmed for each patient in a single patient, double blind, placebo controlled trial. Four patients received two IVIg treatments and two placebo treatments, and two patients received one IVIg and one placebo treatment in a randomised order. Five out of six patients responded to IVIg but not to placebo. One patient responded to IVIg in the same manner as to placebo treatment. Thus IVIg treatment can lead to improvement of muscle strength in patients with MMN.

Basic fibroblast growth factor immunoreactivity in the peripheral motor system of the rat.

We have used immunohistochemistry and electron microscopy to investigate the distribution of basic fibroblast growth factor (bFGF) in the peripheral motor system of the adult rat. In the lumbar segments of the spinal cord, bFGF immunoreactivity (bFGF-I) was seen in motor neurons and glial cells but not in axons. The neuronal immunostaining was seen as two or three intensely fluorescent spots in the nuclei with weak and more diffuse staining of the perinuclear cytoplasm. In the sciatic nerve, bFGF-I was seen in Schwann cells with strong intensity at the nodes of Ranvier. Axonal immunostaining could not be detected. At the electron microscopic level, the intense nodal immunostaining of Schwann cells was confirmed and was found to be localized to the Schwann cell membrane at the nodal gap. The intensity of staining decreased with distance from the node. In the soleus and gastrocnemius muscles, bFGF-I was seen at the motor endplates in sites corresponding to the motor nerve terminals in addition to faint staining within the muscle fibers. Electron microscopy showed that bFGF-I was localized within the nerve terminals. Histochemical localization of bFGF in the peripheral motor system is compatible with the functions ascribed for this protein in this system.

Insulin-like and fibroblast growth factors in spinal cords, nerve roots and skeletal muscle of human controls and patients with amyotrophic lateral sclerosis.

Insulin-like growth factors (IGF-I and IGF-II) and fibroblast growth factors [acidic FGF (aFGF) and basic FGF (bFGF)] are trophic for motor neurones in vitro and (in laboratory animals) in vivo. An immunohistochemical investigation was performed on the distribution of these factors in the neuromuscular system of control patients and patients with amyotrophic lateral sclerosis (ALS). Comparisons were made with rat tissue. IGF-I immunoreactivity (IGF-I-IR) was seen in motor neurone cell bodies and axons, astroglia and Schwann cells, and in muscle fibres. IGF-II-IR was weak in all these cells. aFGF-IR was present in motor neurone cell bodies and axons, oligodendroglia and muscle fibres, but was not demonstrable in Schwann cells. bFGF-IR was present in motor neurone cell bodies and axons, and in astroglia, but was not seen in Schwann cells or muscle fibres. The distribution of the IGFs and FGFs in material from motor neurone disease (MND) and controls was similar. A role for any of these factors in the etiology of MND is, therefore, unlikely. IGF-I-IR and aFGF-IR were stronger in type II than in type I muscle fibres and were increased in denervated fibres. Species differences were found for IGF-I and bFGF. The function of these factors is apparently not entirely similar in humans and rats.

Inflammatory cells in the peripheral nervous system in motor neuron disease.

We examined post-mortem material of the peripheral nervous system of 26 cases of motor neuron disease (MND) for the presence of lymphocyte subsets and macrophages. Findings were quantified and compared with those in control nerves. Lymphocytes in chronic and acute axonal degeneration were studied in sural nerve biopsy and animal material. Signs of demyelination were studied in MND and controls with infiltrates of T cells. A few T lymphocytes were scattered diffusely within the fascicles. The numbers did not differ between MND and controls. About half of the T cells was positive for CD45RA, the other half being positive for CD45RO. T cells were negative for CD25, CD54 and major histocompatibility complex (MHC)-class II. There were hardly any B lymphocytes. The numbers of lymphocytes in nerves with and without axonal degeneration did not differ. Increased MHC class II expression was present on denervated Schwann cells and macrophages in MND and in sural nerves with axonal degeneration. Macrophages were increased in number and in size, both in MND and in control material with axonal degeneration. No signs of demyelination were present either in MND or in controls. It is concluded that a T cell-mediated process in peripheral nerves in MND is very unlikely.

Peripheral nerve lesions: the neuropharmacological outlook.

A review is presented of compounds with trophic effects on the peripheral nervous system. A distinction should be made between three types of effect: enhancement of neurone survival, stimulation of regeneration and induction or stimulation of collateral sprouting. On the basis of data currently available, laminin and insulin-like growth factor I are the most promising substances for regeneration of peripheral nerve lesions. Future investigations of laminin should provide an answer to the query whether local administration facilitates sprouts to cross the gap between proximal and distal nerve stumps. Further experiments are required on effects of systemic administration of IGF-I in animal models of peripheral nerve lesions before investigations can be initiated in man.

Nerve growth factor receptor immunostaining in the spinal cord and peripheral nerves in amyotrophic lateral sclerosis.

In animal experiments, nerve transection is followed by expression of nerve growth factor receptors (NGFR) on Schwann cells of both motor and sensory nerve fibres distally to the site of the lesion. To determine whether denervated Schwann cells in amyotrophic lateral sclerosis (ALS) similarly express NGFR, a study was made of post-mortem material of peripheral nerves and ventral roots from ALS cases and age-matched controls, using immunolabelling methods. Dorsal roots and spinal cords were also examined for the presence of NGFR. In all the ALS cases and controls, NGFR immunostaining was seen in the outer layer of vessel walls, perineurial sheaths, connective tissue surrounding fascicles in nerve roots and in the substantia gelatinosa of the spinal cord. In ALS, NGFR staining was also present in the Schwann cells of degenerated nerve fibres in mixed peripheral nerves, in ventral roots and, to a lesser extent, in dorsal roots. NGFR immunoreactivity was also seen in elongated cells extending from the perifascicular connective tissue into the nerve fascicles. It is concluded that denervated Schwann cells in ALS express NGFR and that NGFR immunostaining on Schwann cells may be used as an indicator of axonal degeneration. The NGFR labelling in the dorsal roots supports the notion that ALS is not a pure motor syndrome.

Long-term follow-up of 71 patients with thunderclap headache mimicking subarachnoid haemorrhage.

Seventy-one patients with sudden, severe, and unusual headache, but with normal computerised tomographic scan and cerebrospinal fluid, were followed for an average of 3.3 years. Twelve patients (17%) had identical recurrences, but again without evidence of subarachnoid haemorrhage. Findings on cerebral angiography, performed in four patients after the first attack and in two patients after recurrent episodes, were normal. Thirty-one (44%) of the seventy-one patients subsequently had regular episodes of tension headache or common migraine. If the computerised tomographic scan and cerebrospinal fluid findings are normal, this type of headache can be regarded as a benign symptom, and cerebral angiography is not indicated.

Activation of the fibrinolytic system during intracoronary streptokinase administration.

Serial biochemical studies were performed in 12 patients treated with intracoronary streptokinase infusion for acute myocardial infarction, in order to study the method of activation of the fibrinolytic system during local administration of a relatively low dose of this drug and to determine correlations between systemic effects and reperfusion. Plasma samples were obtained before and every 15 minutes during the infusion of streptokinase and after completion of the therapy. Streptokinase dosage in this study was 211,000 +/- 88,000 IU (+/- SD). The average time from the onset of symptoms to the start of infusion was 2 hours 50 minutes (range 1 hour 10 minutes to 3 hours 30 minutes). Reperfusion occurred in six patients and temporary recanalization in three; in three patients no recanalization was achieved. Fibrinolytic assays of pretreatment plasma samples revealed elevated levels of plasminogen activators, presumably caused by the release of tissue-type plasminogen activator after a condition of stress. Plasminogen concentrations decreased from 94 +/- 17% to 44 +/- 30%. Alpha 2-antiplasmin fell from 84 +/- 27% to 12 +/- 19%; in seven patients no plasmin inhibitor activity was measurable at the completion of the infusion. Free plasmin occurred in samples only when this inhibitor had disappeared. This resulted in a lytic state leading to degradation of fibrinogen, the levels of which fell from 2.9 +/- 0.7% to 1.5 +/- 1.1%. Fibrinogen degradation products, measured in plasma with monoclonal antibodies, increased exponentially during streptokinase infusion in at least four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Responders and non-responders after fluoride therapy in osteoporosis.

Patients with osteoporosis were treated for two years with sodium fluoride. Fifteen received sodium fluoride in capsules, 56 in enteric coated slow release tablets (Ossin) and 20 in enteric coated tablets (Procal). Seven women treated with Procal were also treated with oestrogens. All patients had a calcium intake between 1000 and 2000 mg/day, used dihydrotachysterol for vitamin suppletion and were advised to exercise. Non-responders were arbitrarily defined as those who had an increase in serum alkaline phosphatase less than 10 U/l, those who had no increase in bone mineral content measured with CT in L4 and those who got a femoral neck fracture during the period of therapy. In the overall group of 91 patients 20% were non-responders based on a serum alkaline phosphatase increase less than 10 U/l. Based on the changes in bone mineral content 40% were non-responders during the first year of treatment, 45% during the second year and 23% over the first plus second year. The impression is that patients with a femoral neck fracture have a higher increase in serum parathyroid hormone concentration than patients without fractures. The urinary excretion of fluoride has a better predictive value than the change in serum alkaline phosphatase concentration for the prediction of an increase in bone mineral content.

Fracture prevalence and bone mineral mass in osteoporosis measured with computed tomography and dual energy photon absorptiometry.

In 174 adults presenting with backache, bone densitometry was performed on the lumbar spine, both femoral necks, and one femoral shaft employing dual energy photon absorptiometry (DPA); in 112 of these, densitometry was undertaken on L4 using single energy quantitative computer assisted tomography (CT). Radiographs of the spine were obtained in all patients and those with known or suspected malignant disease were excluded. The subjects were divided into two groups according to the presence (n = 128) or absence (n = 44) of signs of vertebral collapse or compression. The predictive value of the densitometric results for the presence of vertebral fractures was calculated and used as an estimate of fracture risk. While CT showed somewhat higher predictive values than DPA of the spine or combinations of DPA results from spine and femoral necks, the difference was not significant. It is concluded that with both CT and DPA the probability of the presence or absence of fracture can be raised to 75-80% when the probability prior to the investigation is 50% and when the threshold values of the measurements are chosen so that their sensitivity and specificity are about equal.

Agenesia de vesicula biliar e ducto cistico: apresentacao de um caso e revisao da literatura. / Agenesis of the gallbladder and cystic duct: report of a case and review of the literature

A agenesia de vesicula biliar e do ducto cistico e uma malformacao pouco frequente, devida a uma anomalia do desenvolvimento da porcao caudal presente no embriao de 3 mm: apenas 181 casos em 1.352.000 necropsias.Em grande numero de casos ela e asintomatica, mas os casos que vao a cirurgia sao levados por sintomas que simulam colecistite ou colelitiase, o que ocorre com maior frequencia no sexo feminino (2:1) e entre os 40 e 50 anos. O caso apresentado preenche todos os criterios adotados para uma comprovacao transoperatoria de tal raridade, e ainda foi seguida no pos-operatorio de ecografia hepatica, recurso indispensavel para excluir existencia de vesicula biliar intra-hepatica (por si tambem pouco frequente). Relata-se na literatura a existencia de outras malformacoes congenitas associadas, sendo que a paciente aqui descrita tinha uma anomalia da veia porta