Publications (34)99.13 Total impact
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Article: Effect of ageing on the retinal vascular responsiveness to flicker light in glaucoma patients and in ocular hypertension.
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ABSTRACT: AIM: To evaluate the effect of ageing on the retinal vascular responsiveness to flicker light in glaucoma and ocular hypertension (OHT). METHODS: Retinal vascular response to flicker was measured with the retinal vessel analyser in 56 healthy subjects (59±9 years), 50 primary open-angle glaucoma (POAG) (60±10 years) and 46 OHT patients (62±9 years). In the glaucoma group, the less damaged eye; in the OHT group, the eye with the higher intraocular pressure; and in healthy controls, one randomly selected eye was considered. Parametric and non-parametric linear regression analysis, as well as a model of covariance analysis (ANCOVA) was used to evaluate the effect of age on the vascular response. RESULTS: In all three groups (N=152) absolute (Pearson R: -0.19, p<0.019; Spearman R: -0.22, p<0.006) and relative change (Pearson R: -0.18, p<0.027; Spearman R: -0.21, p<0.010) were statistically associated with age. The ANCOVA showed no difference between the three groups in this regard (absolute change: p=0.43; relative change: p=0.51). CONCLUSIONS: Vascular responsiveness to flicker light decreases with age in healthy individuals, in glaucoma patients and in OHT patients. This effect seems to be comparable between the tested groups, and age-related change in vascular responsiveness to flicker light seems an unlikely risk factor for glaucoma.The British journal of ophthalmology 04/2013; · 2.92 Impact Factor -
Article: Diurnal Blood Pressure Variations Are Associated with Changes in Distal–Proximal Skin Temperature Gradient
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ABSTRACT: It is generally assumed that skin vascular resistance contributes only to a small extent to total peripheral resistance and hence to blood pressure (BP). However, little is known about the impact of skin blood flow (SBF) changes on the diurnal variations of BP under ambulatory conditions. The main aim of the study was to determine whether diurnal patterns of distal SBF are related to mean arterial BP (MAP). Twenty-four-hour ambulatory measurements of BP, heart rate (HR) and distal (mean of hands and feet) as well as proximal (mean of sternum and infraclavicular region) skin temperatures were carried out in 51 patients (men/women = 18/33) during a 2-d eye hospital investigation. The standardized ambulatory protocol allowed measurements with minimal interference from uncontrolled parameters and, hence, some conclusive interpretations. The distal minus proximal skin temperature gradient (DPG) provided a measure for distal SBF. Individual cross-correlation analyses revealed that the diurnal pattern of MAP was nearly a mirror image of DPG and hence of distal SBF. Scheduled lunch and dinner induced an increase in DPG and a decline in MAP, while HR increased. Low daytime DPG (i.e. low distal SBF) levels significantly predicted sleep-induced BP dipping (r = −.436, p = .0014). Preliminary path analysis suggested that outdoor air temperature and atmospheric pressure may act on MAP via changed distal SBF. Changes in distal SBF may contribute to diurnal variation in MAP, including sleep-induced BP dipping and changes related to food intake. This finding might have an impact on individual cardiovascular risk prediction with respect to diurnal, seasonal and weather variations; however, the underlying mechanisms remain to be discovered.Chronobiology International 09/2012; 29(9):1273-1283. · 4.03 Impact Factor -
Article: Relationship between gender role, anger expression, thermal discomfort and sleep onset latency in women
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ABSTRACT: BackgroundWomen with thermal discomfort from cold extremities (hands and feet; TDCE) often suffer from prolonged sleep onset latency (SOL). Suppressed anger could contribute to the genesis of both TDCE and prolonged SOL. The aim of the study was to test the hypothesis whether stereotypic feminine gender socialization (SFGS) is related to anger suppression (experienced anger inwards, Anger-In), which in turn could affect TDCE and SOL. Methods148 women, a sub-sample of a larger survey carried out in the Canton Basel-Stadt (Switzerland), sent back detailed postal questionnaires about SOL, TDCE, anger expression (STAXI, state -trait -anger -expression -inventory) and SFGS using a gender power inventory, estimating the degree of gender specific power expression explicitly within women by stereotypic feminine or male attribution. Statistics was performed by path analysis. ResultsA significant direct path was found from stereotypic feminine attribution to Anger-In and prolonged SOL. Additionally, a further indirect path from Anger-In via TDCE to SOL was found. In contrast, stereotypic male attribution was not related to Anger-In but was significantly associated with outwardly expressed anger. LimitationsSelf-reported data, retrospective cross-sectional survey, prospective studies are required including physiological measurements. ConclusionStereotypic feminine gender socialization may play an important determinant for anger suppression, which subsequently can lead to thermal discomfort from cold extremities and prolonged sleep onset latency.BioPsychoSocial Medicine 04/2012; 3(1):1-7. -
Article: Inactivation of MARCH5 Prevents Mitochondrial Fragmentation and Interferes with Cell Death in a Neuronal Cell Model.
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ABSTRACT: To study the impact of the mitochondrial ubiquitin ligase MARCH5 on mitochondrial morphology and induction of apoptosis using an in vitro model of neuronal precursor cells exposed to glaucoma-relevant stress conditions. RGC5 cells transfected with expression constructs for MARCH5, MARCH5(H43W), Dpr1(K38A) or vector control were exposed to either elevated pressure of 30 mmHg, oxidative stress caused by mitochondrial electron transport chain (ETC) inhibition, or hypoxia-reoxygenation conditions. Mitochondrial morphology of RGC5 cells was analyzed following staining of the mitochondrial marker cytochrome c and photoactivatable GFP (PAGFP) diffusion assay. Induction of apoptotic cell death in these cells was determined by analyzing the release of cytochrome c from mitochondria into the cytosol and flow cytometry. Exposure of RGC5 cells to oxidative stress conditions as well as to elevated pressure resulted in the fragmentation of the mitochondrial network in control cells as well as in cells expressing MARCH5. In cells expressing inactive MARCH5(H43W) or inactive Drp(K38A), mitochondrial fragmentation was significantly blocked and mitochondrial morphology was comparable to that of control cells under normal conditions. Exposure of RGC5 cells to elevated pressure or oxidative stress conditions induced apoptotic cell death as assessed by cytochrome c release and DNA staining, while expression of dominant-negative MARCH5(H43W) or Drp1(K38A) did significantly delay cell death. Preventing mitochondrial fragmentation through interference with the mitochondrial fission machinery protects neuronal cells from programmed cell death following exposure to stressors physiologically relevant to the pathogenesis of glaucoma.PLoS ONE 01/2012; 7(12):e52637. · 4.09 Impact Factor -
Article: Postoperative microhyphema as a positive prognostic indicator in canaloplasty.
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ABSTRACT: Purpose: To assess risk factors for failure in canaloplasty. Methods: Nonrandomized prospective study involving 51 eyes of 51 patients with medically uncontrolled primary open-angle glaucoma undergoing canaloplasty. Visual acuity, intraocular pressure (IOP) and slit-lamp examinations were performed before and after surgery at 1 and 7 days, and at 1 month and every 3 months thereafter. Factors like age, gender, preoperative IOP and microhyphema on day 1 were evaluated. Results: The mean follow-up was 20.6 (SD 8.3) months. The mean preoperative IOP was 26.8 (SD 5.2) mmHg; the mean postoperative IOP was 8.4 (4.2) mmHg at day 1 and 12.7 (1.7) mmHg at month 24. Microhyphema was found in 40 patients (85.1%) on day 1 after surgery. The height of microhyphema was 1.8 mm ± 0.4 (SD) (range 1-2.5), and the time of resorption was 6.6 days ± 2.8 (SD) (range 3-14) on average. No recurrence of hyphema has been observed. IOP < 16 mmHg without medications depended significantly on the presence of microhyphema (hazard ratios, HR 0.03, 95% CI 0.01-0.25, p < 0.001), but not on age (HR 1.00, 95% CI 0.91-1.09, p = 0.32), preoperative IOP (HR 0.98, 95% CI 0.85-1.12, p = 0.80), cup-to-disc ratio (HR 0.15, 95% CI 0.00-20.01, p = 0.45) and gender (HR 0.24, 95% CI 0.05-1.12, p = 0.07). Factors like preoperative IOP, age, gender, cup-to-disc ratio were not associated with microhyphema. There were no significant differences between patients with versus without microhyphema in regard to age, preoperative IOP, morphological and functional glaucomatous damage, number of medications and postoperative day 1 IOP. However, patients with microhyphema had significantly fewer Nd:YAG goniopunctures after surgery than patients without microhyphema (p < 0.001). Conclusion: Microhyphema the first postoperative day seems to be a significant positive prognostic indicator in uneventful canaloplasty in regard to IOP reduction, possibly representing a restored and patent physiologic aqueous outflow system.Acta ophthalmologica 12/2011; · 2.44 Impact Factor -
Article: Use of colour Doppler imaging in ocular blood flow research.
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ABSTRACT: The main objective of this report is to encourage consistent quality of testing and reporting within and between centres that use colour Doppler imaging (CDI) for assessment of retrobulbar blood flow. The intention of this review is to standardize methods in CDI assessment that are used widely, but not to exclude other approaches or additional tests that individual laboratories may choose or continue to use.Acta ophthalmologica 12/2011; 89(8):e609-30. · 2.44 Impact Factor -
Article: Compartment syndrome in the optic nerve: a new hypothesis in the pathogenesis of glaucoma.
Acta ophthalmologica 02/2011; · 2.44 Impact Factor -
Article: Heart-rate variability in women during 40-hour prolonged wakefulness.
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ABSTRACT: Heart-rate variability patterns of 18 women during a 40-h constant routine of prolonged wakefulness under controlled laboratory conditions were analyzed. The authors tested the circadian timing of the autonomic nervous system and the relationship between the sympathetic and vagal branches in women with both a functional disorder of vascular regulation (main symptom: cold hands and feet) and prolonged sleep onset and controls without these symptoms. Spectral analysis of R-R intervals during paced breathing episodes revealed significantly lower power values in the high-frequency band (HF; 0.15-0.4 Hz) but not in the low-frequency band (LF; 0.04-0.15 Hz), leading to a significantly elevated LF/HF ratio in the former group. A significant circadian rhythm in LF power and heart rate occurred in both groups, and a significant correlation was found between sleepiness and sympathovagal balance (r = .53, p < .05). These findings indicate not only an autonomic imbalance in the first group compared with controls, but also two strategies of the autonomic nervous system to fight against fatigue in women. One implies circadian control and the other homeostatic control, and both are reflected by the LF/HF ratio.Chronobiology International 09/2010; 27(8):1609-28. · 4.03 Impact Factor -
Article: Thermal discomfort with cold extremities in relation to age, gender, and body mass index in a random sample of a Swiss urban population.
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ABSTRACT: The aim of this epidemiological study was to investigate the relationship of thermal discomfort with cold extremities (TDCE) to age, gender, and body mass index (BMI) in a Swiss urban population. In a random population sample of Basel city, 2,800 subjects aged 20-40 years were asked to complete a questionnaire evaluating the extent of cold extremities. Values of cold extremities were based on questionnaire-derived scores. The correlation of age, gender, and BMI to TDCE was analyzed using multiple regression analysis. A total of 1,001 women (72.3% response rate) and 809 men (60% response rate) returned a completed questionnaire. Statistical analyses revealed the following findings: Younger subjects suffered more intensely from cold extremities than the elderly, and women suffered more than men (particularly younger women). Slimmer subjects suffered significantly more often from cold extremities than subjects with higher BMIs. Thermal discomfort with cold extremities (a relevant symptom of primary vascular dysregulation) occurs at highest intensity in younger, slimmer women and at lowest intensity in elderly, stouter men.Population Health Metrics 01/2010; 8:17. · 2.11 Impact Factor -
Article: Optic-disc hemorrhages: Cause or result of ischemia?
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ABSTRACT: Visual-field defects may develop after optic-disc hemorrhages. The question whether blood may be a major damaging agent for the optic nerve head will be discussed. A female patient with an optic-disc hemorrhage in the left eye was followed with frequent disc photography and computerized perimetry for a period of two months. This patient presented, subsequently to an optic-disc hemorrhage of unknown cause, a delayed progression of the visual-field defect. The fact that the visual-field defect developed after the hemorrhage and was progressive in the next few days indicates that the hemorrhage may not be the result of an infarct, but rather provokes further damage. The case raises the question whether blood components may be involved in the pathophysiologic process of optic-nerve-head atrophy. In analogy of cerebral vasospasm after subarachnoid hemorrhage as an important cause of cerebral ischemia, the potential involvement of blood-related injury to the optic disc should be considered in such patients.07/2009; 14(2):97-101. -
Article: Vasospastic individuals demonstrate significant similarity to glaucoma patients as revealed by gene expression profiling in circulating leukocytes.
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ABSTRACT: There is growing evidence that vasospatic individuals could be predisposed to develop glaucoma. Vasospastic deregulation is ensuing in activation of circulating leukocytes. In previous studies using "gene-hunting" strategies, we demonstrated stable alterations in gene expression profiles of circulating leukocytes isolated from glaucoma patients with vascular deregulation when compared to healthy individuals with no history of glaucomatous damage. The goal of this study was to look for possible similarities in gene expression profiles of circulating leukocytes in vasospastic individuals and glaucoma patients. Normal-tension (NTG) and high-tension (HTG) glaucoma patients as well as individuals with vascular deregulation (VD) and healthy controls were recruited for the gene expression analysis. The methodology of comparative Expression Array analysis followed by highly sensitive quantitative real-time PCR has been used. Compared to the control group the expression of 146, 68, and 60 genes was found to be altered in NTG, HTG, and VD groups respectively. Thirty-four genes demonstrated similar expressional alterations in NTG, HTG, and VD groups versus controls, and only 21 genes demonstrated similar expressional alterations in NTG and HTG groups, having no overlap with the VD group. This result indicates a potential predisposition of vasospastic individuals to glaucomatous optic nerve atrophy. The targeted expression profiles might be further considered for early/predictive glaucoma diagnosis.Molecular vision 01/2009; 15:2339-48. · 2.20 Impact Factor -
Article: Cold extremities and difficulties initiating sleep: evidence of co-morbidity from a random sample of a Swiss urban population.
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ABSTRACT: Difficulties initiating sleep (DIS) can frequently occur in psychiatric disorders but also in the general population. The primary vasospastic syndrome is a functional disorder of vascular regulation in otherwise healthy subjects complaining of thermal discomfort from cold extremities (TDCE). Laboratory studies have shown a close relationship between long sleep onset latency and increased distal vasoconstriction in healthy young subjects. Considering these findings, the aims of the Basel Survey were to assess the prevalence rates for DIS and TDCE and to determine whether both symptoms can be associated in the general population. In a random population sample of Basel-Stadt, 2800 subjects (age: 20-40 years) were requested to complete a questionnaire on sleep behavior and TDCE (response rate: 72.3% in women, n = 1001; 60.0% in men, n = 809). Values of DIS and TDCE were based on questionnaire-derived scores. In addition, TDCE was externally validated in a separate group of subjects (n = 256) by finger skin temperature measurements--high TDCE values were significantly associated with low finger skin temperature. A total of 31.1% of women and 6.9% of men complain of TDCE. In contrast, prevalence rates of DIS were only slightly higher in women in comparison to men (9.3% versus 6.7%, P < 0.1). Irrespective of gender, each seventh subject complaining of TDCE had concomitant DIS and the relative risk in these subjects was approximately doubled. Therefore, a thermophysiological approach to DIS may be relevant for its differential diagnosis and its treatment.Journal of Sleep Research 11/2008; 17(4):420-6. · 3.16 Impact Factor -
Article: Relationship between ocular pulse amplitude and systemic blood pressure measurements.
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ABSTRACT: This study aimed to determine whether ocular pulse amplitude (OPA) measured with dynamic contour tonometry (DCT) is related to systemic blood pressure (BP) parameters. Blood pressure was measured continuously and simultaneously with OPA in one randomly selected eye in 29 healthy subjects. Systemic parameters of interest were: systolic and diastolic BPs and their difference (BP amplitude), and left ventricle ejection time (LVET; defined as the time between the diastolic trough and the incisural notch in the BP curve). In addition, the axial length (AL) of the eye was measured. Associations between OPA, AL and systemic cardiovascular parameters were analysed in a multivariate regression model. Measurements of OPA ranged from 1.0 mmHg to 4.9 mmHg (mean 2.3 +/- 0.9 mmHg, median 1.9 mmHg). In a univariate analysis with one predictor at a time, means of intraocular pressure (IOP) (p = 0.008), AL (p = 0.046) and LVET (p = 0.037) were significantly correlated with OPA, whereas systolic and diastolic BPs and their amplitude were not. A multiple linear regression analysis showed that mean IOP (p < 0.005), AL (p = 0.01) and LVET (p = 0.002) all independently contributed to OPA. The OPA readings measured with DCT in healthy subjects were not related to BP levels and amplitude. It seems that the OPA strongly depends on the time-course of the cardiac contraction. Regulating mechanisms in the carotid system as well as scleral rigidity may be responsible for dampening the direct effect of BP variations.Acta ophthalmologica 10/2008; 87(3):329-34. · 2.44 Impact Factor -
Article: Chronobiological characterization of women with primary vasospastic syndrome: body heat loss capacity in relation to sleep initiation and phase of entrainment.
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ABSTRACT: Women with primary vasospastic syndrome (VS), but otherwise healthy, exhibit a functional disorder of vascular regulation (main symptom: cold extremities) and often suffer from difficulties initiating sleep (DIS). Diverse studies have shown a close association between distal vasodilatation before lights off and a rapid onset of sleep. Therefore, we hypothesized that DIS in women with VS could be due to a reduced heat loss capacity in the evening, i.e., subjects are physiologically not ready for sleep. The aim of the study was to elucidate whether women having both VS and DIS (WVD) or not (controls) show different circadian characteristics (e.g., phase delay of the circadian thermoregulatory system with respect to the sleep-wake cycle). Healthy young women (n = 9 WVD and n = 9 control) completed a 40-h constant routine protocol (adjusted to habitual bedtime) before and after an 8-h sleep episode. Skin temperatures [off-line calculated as distal-proximal skin temperature gradient (DPG)] and core body temperature (CBT; rectal) were continuously recorded. Half-hourly saliva samples were collected for melatonin assay and subjective sleepiness was assessed on the Karolinska Sleepiness Scale (KSS). Compared with control, WVD showed no differences in habitual bed times, but a 1-h circadian phase delay of dim light-melatonin onset (hours after lights on: WVD 14.6 +/- 0.3 h; control 13.5 +/- 0.2 h; P = 0.01). Similar phase shifts were observed in CBT, DPG, and KSS ratings. In conclusion, WVD exhibit a phase delay of the endogenous circadian system with respect to their habitual sleep-wake cycle, which could be a cause of DIS.AJP Regulatory Integrative and Comparative Physiology 03/2008; 294(2):R630-8. · 3.34 Impact Factor -
Article: Is neurovascular coupling of relevance in glaucoma?
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ABSTRACT: Rapid development of functional neuroimaging techniques have brought about a growing interest for neurovascular coupling in neuroresearch, which, in turn, has prompted similar research in ophthalmology. There are now hints that neurovascular coupling is disturbed in glaucoma. The contact of the nerve terminals to the cortical blood vessels is mostly realized through astrocytes. A major defining property of glaucoma, cupping of the optic disk, implies tissue remodeling of the optic nerve head and involves an astrocytic responses. A malfunction of the astrocytes in glaucoma may lead not only to the hallmark of glaucoma-cupping and death of retinal ganglion cells-but also to an accompanying or even preceding disturbance in ocular neurovascular coupling. This article is a short overview of research published in this field so far.Survey of Ophthalmology 12/2007; 52 Suppl 2:S139-43. · 2.35 Impact Factor -
Article: Effect of hospitalization on intraocular pressure in patients with high tension and normal tension glaucoma.
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ABSTRACT: To determine the effect of hospitalization on intraocular pressure (IOP) in glaucoma patients. Prospective case series. IOP was measured on three consecutive days in 26 high-tension (HTG) and 13 normal-tension (NTGwm) glaucoma patients under IOP-lowering treatment, and in 28 normal-tension glaucoma patients without IOP-lowering treatment (NTGnm), and change was compared by analysis of variance. IOP decreased significantly, but comparably, in the three groups and between right and left eyes, although, the relative change to IOP on day 1 was significantly less pronounced in the group without treatment on day 2 and 3 compared with the treated groups. Glaucoma patients showed a significant decrease in IOP during hospitalization. Although this decrease was more pronounced among the treated patients, it was also present in nontreated patients. Consequently, other factors than improved compliance during hospitalization must play a role in this phenomenon.American Journal of Ophthalmology 08/2006; 142(1):179-81. · 4.22 Impact Factor -
Article: Retinal vascular diameter in young subjects with a vasospastic propensity.
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ABSTRACT: Retinal vascular diameters have recently been shown not to be related to an increased risk of open-angle glaucoma. Because vasospastic propensity has been suggested to represent a risk factor for various ocular diseases, especially glaucoma, the steady-state retinal vascular diameter in subjects with a propensity for systemic vascular dysregulation was compared with a group of age-matched gender-matched controls. Thirty healthy non-smoking individuals [female/male 26/4; mean +/- SD age 22.8+/-3.4 (range 18-31) years] were enrolled into the study. Subjects were classified as having vasospasm (15 subjects) if they related a clear history of frequently cold hands and as healthy subjects (15 subjects) if they denied such a history. Vasospastic propensity or the absence of it had to be confirmed by nail-fold capillaroscopy. Vascular diameter of retinal vessels was measured repeatedly on two days with the retinal vessel analyser and corrected for perfusion pressure, age, and refraction. Neither retinal arteriole diameter (P=0.30) or retinal venule diameter (P=0.49), nor retinal arteriole-to-venule ratio (P=0.96), differed between the two experimental groups. Although vasospastic propensity has been suggested to represent a risk factor in various ocular diseases, the steady-state retinal vessel diameters are not altered in healthy vasospastic subjects. It is probable that the steady-state retinal vessel diameters are no adequate risk indicators for the haemodynamic risk in diseases such as glaucoma.Albrecht von Graæes Archiv für Ophthalmologie 05/2006; 244(4):454-9. · 2.17 Impact Factor -
Article: Circulatory response to blood gas perturbations in vasospasm.
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ABSTRACT: To investigate the response of the optic nerve head and the choroidal circulation to blood gas perturbations in otherwise healthy subjects with a history of cold hands. Thirty-five healthy subjects were selected and grouped according to the related history of cold hands. All 12 selected male subjects, aged 21 to 38 years (mean +/- SD = 28 +/- 5.2 years) had a negative history of cold hands. Female subjects were almost equally divided between the groups with a negative (11 subjects, aged 18-36 years; mean, 25.7 +/- 5.5) or positive (12 subjects, aged 19-45 years; mean, 25 +/- 6.8) history of cold hands. Blood gas perturbations were created by having subjects breath a gas mixture consisting of 21% O(2), 74% N(2), and 5% CO(2). The partial pressures pCO(2) and pO(2) were continuously monitored transcutaneously. Choroidal and optic nerve head blood flow response was evaluated by means of laser Doppler flowmetry. Systolic and diastolic blood pressure (SBP/DBP at baseline, three-group average: 111.2/71.9 mm Hg), heart rate (HR; 70.3 bpm), and intraocular pressure (IOP; 14.7 mm Hg) increased during the blood gas perturbation phase (123.1/77.7 mm Hg, 78.5 bpm, and 15.6 mm Hg, respectively) and returned to baseline in the recovery phase (109.9/73.4 mm Hg, 69.5 bpm, and 13.5 mm Hg, respectively). There was no difference between groups (one-way ANOVA of the percentage change from baseline for SBP, P = 0.75; DBP, P = 0.36; HR, P = 0.95; and IOP, P = 0.72). pCO(2) increased from 5.52 to 6.59 kPa and returned to 5.50 kPa. pO(2) increased from 10.64 to 13.12 kPa and returned to 10.73 kPa. Again, there was no difference between groups (one-way ANOVA for the percentage change: pCO(2), P = 0.17; pO(2), P = 0.78). In the women with vasospasm, optic nerve head blood flow increased 17.1% and the choroidal blood flow decreased -3.6%, whereas in the women and men without vasospasm the optic nerve head blood flow decreased -5.8% and -4.8%, and the choroidal blood flow increased 13.3% and 18.3%, respectively (two-way ANOVA interaction; P = 0.001). The pCO(2) increase was accompanied by a pO(2) increase. Blood pressure and HR increased comparably in all groups, indicating sympathetic arousal. The women with vasospasm demonstrated an inverse response pattern of choroidal and optic nerve head circulation to blood gas perturbation compared with the women without vasospasm and compared with the men.Investigative Ophthalmology & Visual Science 10/2005; 46(9):3288-94. · 3.60 Impact Factor -
Article: High sensitivity of human melatonin, alertness, thermoregulation, and heart rate to short wavelength light.
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ABSTRACT: Light can elicit acute physiological and alerting responses in humans, the magnitude of which depends on the timing, intensity, and duration of light exposure. Here, we report that the alerting response of light as well as its effects on thermoregulation and heart rate are also wavelength dependent. Exposure to 2 h of monochromatic light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm monochromatic light, concomitant with a significantly greater alerting response and increased core body temperature and heart rate ( approximately 2.8 x 10(13) photons/cm(2)/sec for each light treatment). Light diminished the distal-proximal skin temperature gradient, a measure of the degree of vasoconstriction, independent of wavelength. Nonclassical ocular photoreceptors with peak sensitivity around 460 nm have been found to regulate circadian rhythm function as measured by melatonin suppression and phase shifting. Our findings-that the sensitivity of the human alerting response to light and its thermoregulatory sequelae are blue-shifted relative to the three-cone visual photopic system-indicate an additional role for these novel photoreceptors in modifying human alertness, thermophysiology, and heart rate.Journal of Clinical Endocrinology & Metabolism 04/2005; 90(3):1311-6. · 6.50 Impact Factor -
Article: Reduced thirst in patients with a vasospastic syndrome.
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ABSTRACT: To compare thirst, drinking behaviour, and endothelin-1 (ET-1) plasma levels between vasospastic and non-vasospastic subjects. We compared 67 subjects with a primary vasospastic syndrome with 64 age- and sex-matched non-vasospastic control subjects. A detailed medical history was recorded, including a questionnaire containing queries about thirst and drinking behaviour, history of migraine or unspecific headache, history of episodes of low blood pressure, and smoking habits. Body mass index (BMI) was calculated and blood samples were drawn for ET-1 measurements. Subjects with a vasospastic syndrome reported a reduced desire to drink and a lower estimated quantity of daily fluid intake, more often forgot to drink, more often had both migraine and unspecific headache, more often had episodes of low blood pressure, and had an increased plasma level of ET-1. These features differed statistically significantly between the two groups. There was also a non-significant trend among vasospastic subjects to smoke less and to have a smaller BMI. A reduced desire to drink is found frequently among vasospastic subjects.Acta Ophthalmologica Scandinavica 01/2005; 82(6):738-40. · 1.85 Impact Factor
Top co-authors
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Institutions
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2008–2011
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Universitätsspital Basel
Basel, BS, Switzerland
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2010
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Universitäre Psychiatrische Kliniken Basel
Basel, BS, Switzerland
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1994–2009
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Universität Basel
Basel, BS, Switzerland
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