Mythos Migr?ne

Migraine is the most frequent cause of headache in patients seeking medical advice. Even ophthalmologists are frequently confronted with this diagnosis. In many cases a diagnosis can be easily established by a targeted patient history. Accompanying symptoms deserve attention, especially the aura which often leads patients directly to the ophthalmologist. Concerning migraine therapy well-established guidelines exist but despite this many patients remain undiagnosed and inadequately treated. Many myths and half-truths are associated with migraine headache. This article aims to give an overview for ophthalmologists.     

Pupillary light reflexes in patients with Leber’s hereditary optic neuropathy

 Background: According to a recent pupillographic study, patients with Leber’s hereditary optic neuropathy (LHON) show the same pupillary behaviour as normals. Because this raises many questions concerning the real nature of LHON and challenges our concept of the afferent pupillary system, we tried to verify the results of this study. · Methods: Pupillary function was assessed in 34 normal subjects and 40 patients with LHON. Pupillary light reflexes were recorded by means of the Compact Integrated Pupillograph (CIP, AMTech). Under mesopic conditions 200-ms stimuli were presented at two different stimulus intensities. Latency, constriction amplitude and baseline diameter were defined automatically. Pupil light reflexes were compared between LHON patients and normals and between the better and the worse eye in 20 LHON patients with different visual acuities. · Results: For both stimuli there were significant differences in latency between LHON patients and controls. The latency of the pupil light reflex proved to be about 20 ms longer for LHON patients, and the amplitude was significantly smaller for the bright stimulus. Within LHON patients, the eyes with the worse visual acuity had a significantly smaller constriction amplitude than the eyes with the better visual acuity. · Conclusion: The results of our study confirm that LHON really is an optic nerve disease and that the pupillary light reflexes are not normal. Received: 5 January 1998 Revised version received: 28 February 1998 Accepted: 11 March 1998     

The nonmevalonate pathway supports both monoterpene and sesquiterpene formation in snapdragon flowers

Terpenoids, the largest class of plant secondary metabolites, play essential roles in both plant and human life. In higher plants, the five-carbon building blocks of all terpenoids, isopentenyl diphosphate (IPP) and dimethylallyl diphosphate, are derived from two independent pathways localized in different cellular compartments. The methylerythritol phosphate (MEP or nonmevalonate) pathway, localized in the plastids, is thought to provide IPP and dimethylallyl diphosphate for hemiterpene, monoterpene, and diterpene biosynthesis, whereas the cytosol-localized mevalonate pathway provides C5 units for sesquiterpene biosynthesis. Stable isotope-labeled, pathway-specific precursors (1-deoxy-[5,5-2H2]-D-xylulose and [2,2-2H2]-mevalolactone) were supplied to cut snapdragon flowers, which emit both monoterpenes and the sesquiterpene, nerolidol. We show that only one of the two pathways, the plastid-localized MEP pathway, is active in the formation of volatile terpenes. The MEP pathway provides IPP precursors for both plastidial monoterpene and cytosolic sesquiterpene biosynthesis in the epidermis of snapdragon petals. The trafficking of IPP occurs unidirectionally from the plastids to cytosol. The MEP pathway operates in a rhythmic manner controlled by the circadian clock, which determines the rhythmicity of terpenoid emission.     

An approach to differentiate between noradrenaline-elicited contractile processes in the rat isolated aorta

Summary The aim of the present study was to assess the different processes contributing to the contraction induced by noradrenaline (NA, 1 gmol/l) in the rat isolated aorta. Pretreatment with maximally effective concentrations of nifedipine or cromakalim reduced the NA-induced contraction to 80 ± 3.5% or 63 ± 2.0%, respectively, without alteration of the shape of the response. After pretreatment with Mn²⁺, NA caused a transient phasic contraction followed by a sustained tonic component, comparable to the response obtained in Ca²⁺-free medium. Ryanodine — in the presence of extracellular Ca²⁺ — caused a slight increase of resting tension, but did not modify the NA-induced contraction. In Ca²⁺-free medium the contraction elicited by NA consisted of a transient phasic and a sustained tonic component. The amplitude of the phasic contraction decreased exponentially with the time of exposure to Ca²⁺-free medium. The phasic component was identified as elicited by Ca²⁺ released from the sarcoplasmic reticulum (SR) by means of ryanodine. If Ca²⁺ depleted tissues (80 min in Ca²⁺-free solution) were exposed to Ca²⁺ in the presence of Mn²⁺ or cromakalim, the NA-induced phasic response was inhibited, suggesting that Mn²⁺ and cromakalim blocked the refilling of the store. It can be concluded that activation of ₁-adrenoceptors in the rat aorta by NA elicits Ca²⁺-entry processes which have a different sensitivity to nifedipine, cromakalim and Mn²⁺. The Ca²⁺ released from SR contributes about 20% to the overall contractile response. Our data suggest that the depleted SR can be refilled from the extracellular space via a direct cromakalim- and Mn²⁺-sensitive pathway. Send offprint requests to: B. Wilffert at the above address     

Immune reactivity towards insulin, its amyloid and protein S100B in blood sera of Parkinson's disease patients

Peripheral immune responses can be sensitive indicators of disease pathology. We evaluated the autoimmune reactions to endocrine (insulin) and astrocytical (S100B) biomarkers in the blood sera of 26 Parkinson's disease (PD) patients compared with controls by using ELISA. We found a statistically significant increase of the autoimmune responses to both antigens in PD patients compared with controls with a mean increase of 70% and 50% in the autoimmune reactions towards insulin and S100B, respectively. Heterogeneity of the immune responses observed in patients may reflect the modulating effect of multiple variables associated with neurodegeneration and also changes in the basic mechanisms of individual autoimmune reactivity. We did not detect any pronounced immune reactions towards insulin amyloid fibrils and oligomers in PD patients, indicating that an amyloid-specific conformational epitope is not involved in immune recognition of this amyloid type, while sequential epitope of native insulin is hidden within the amyloid structures. Immune reactions towards S100B and insulin may reflect the neurodegenerative brain damaging processes and impaired insulin homeostasis occurring in PD.     

Dosimetrie an HDR-Afterloading-Geräten mit Ir-192- und Co-60-Strahler: Vergleich verschiedener internationaler Dosimetrieprotokolle

The air kerma rate in air at a reference distance of 1 meter from the source is the recommended quantity for the specification of gamma ray source in brachytherapy. The absorbed dose for the patients is directly proportional to the air kerma rate. Therefore the air kerma rate should be determined before the first use of the source on patients by a medical physicist who is independent from the source manufacturer. The air kerma rate will then be applied in the calculation of the dose delivered to patients.In practice, high dose rate (HDR) Ir-192 afterloading machines are mostly used in brachytherapy treatment. Currently HDR-Co-60 increasingly come into operation, too. The essential advantage of the use of Co-60 sources is its longer half-life compared to Ir-192. In addition, the purchasing and disposal costs are lower. The use of HDR-Co-60- afterloading machines is also quite interesting for developing countries.This work describes the dosimetry at HDR afterloading machines according to the protocols DIN 6809-2 (1993) in relation to the DGMP-Report 13 (2006), IAEA-TECDOC-1274 (2002) and AAPM Report 41 (1993) with the nuclides Ir-192 and Co-60. We have used 3 different measurement methods (with a cylindrical chamber in solid phantom and in free air and with a well chamber) in dependence of each of the protocols.We have shown that the standard deviations of the measured air kerma rate for the Co-60 source are generally larger than those of the Ir-192 source. The measurements with the well chamber had the lowest deviation from the certificate value. In all protocols and methods the deviations stood for both nuclides by a maximum of about 1.2% for Ir-192 and 2.5% for Co-60-sources respectively.     

Significance of eosinophilic granulocytes in chronic subdural hematomas

Despite a number of studies on infiltration of eosinophilic granulocytes into the outer membrane of chronic subdural hematomas, the significance of this phenomenon is not clear. We investigated histologically the membranes of 40 patients with chronic subdural encapsulated hematoma. Infiltrations with eosinophilic leucocytes were found in the granulation tissue of the inner layer of the outer membrane, either diffuse and sporadic (12 cases) or as massive agglomerations (28 cases). Fifty percent of the patients with marked infiltrations were between 61 and 80 years old. In 5 cases Charcot-Leyden crystals were identified. The numerous functions of the eosinophils play a more important role in repair than in maintenance of fluidity of hematomas.     

The use of the endothelin receptor antagonist, tezosentan, before or after renal ischemia protects renal function

BACKGROUND: Utilization of organs subjected to ischemia/reperfusion (I/R) injury could expand the donor pool. Endothelin (ET) is implicated in renal I/R injury. Therefore, our study compared the effectiveness of pre- and postischemic administration of the ET receptor antagonist, Tezosentan, in preserving renal function. METHODS: In a rat model, a kidney was subjected to 45 min of ischemia along with a contralateral nephrectomy. After 24 hr of reperfusion, renal function was assessed by serum creatinine (Scr), inulin clearance (glomerular filtration rate; GFR), and histology. ET-1 peptide expression was localized using immunohistochemistry. Three groups were studied: I/R untreated (n=17), I/R pretreated (n=11), and I/R posttreated (n=13) with Tezosentan (15 mg/kg, i.v.). RESULTS: Tezosentan significantly decreased (P<0.05) the rise in Scr from I/R injury (2.0+/-0.4 mg/dl, before and 2.9+/-0.4 mg/dl, after treatment) compared with untreated animals (4.2+/-0.4 mg/dl). GFR was significantly increased (P<0.05) from 0.13+/-0.03 ml/min (untreated animals) to 0.74+/-0.16 and 0.47+/-0.14 ml/min (pre- and posttreated animals). Untreated animals had significant cortical acute tubular necrosis, which was almost completely prevented by pretreatment with Tezosentan and markedly reduced by posttreatment. Increased ET-1 peptide expression was noted in the renal vasculature and in the cortical tubular epithelium of kidneys exposed to I/R. CONCLUSIONS: The purpose of this study was to optimize the function of kidneys exposed to I/R injury. Pretreatment as well as posttreatment with Tezosentan successfully decreased Scr, increased GFR, and maintained renal architecture in kidneys after ischemia. Therefore, ET receptor antagonists may be useful to preserve renal function in the transplantation setting.     

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Objective

The purpose of the present study was to provide validation and accuracy data for the pupillographic sleepiness test (PST), on the one hand, by applying self and observer ratings and, on the other hand, by fusioned self and observer ratings as a sleepiness reference value.

Methods

A total of 30?healthy women and men participated in a partial sleep deprivation study (20.00?C04.00?h) and PST measurements were conducted every 2?h for a total of 113?PST measurements. Karolinska Sleepiness Scale (KSS)-based self-reports and five video-based observer ratings of drowsiness (ORD) were measured immediately before the PST in order to provide reliable reference sleepiness values.

Results

PST parameters (pupil unrest index, power of frequency) correlated significantly with the sleepiness validation criteria the KSS and ORD used in this study. Fusioned reference values obtained from one self-report and observer ratings showed a correlation of r?=?0.54, a mean absolute percentage error of 1.58 KSS points, and an error of 35%.

Conclusion

Our results indicate the moderate validity of the PST. Furthermore, the proposed sleepiness reference value might serve as a feasible intermediate solution to estimate sleepiness in the sense of a reference (??quasi-ground truth??) value. This might be true especially for within-subject designs with a focus on the time course of sleepiness. Moreover, the results might show the necessity to recalculate the thresholds of the current PST categories of sleepiness severity.