Retinal atrophy using optical coherence tomography (OCT) in 15 patients with multiple sclerosis and comparison with healthy subjects

INTRODUCTION: Multiple sclerosis is a common disabling progressive neurological disorder. Axonal loss is thought to be a likely cause of persistent disability after a multiple sclerosis relapse. Retinal nerve fiber layer (RNFL) imaging by optical coherence tomography (OCT) seems to be a non-invasive way of detecting optical axonal loss following optic neuritis. OBJECTIVE: To determine whether multiple sclerosis affects retinal nerve fiber layer measurements obtained with optical coherence tomography (OCT3-Carl Zeiss Meditec, Dublin, California, USA). MATERIAL AND METHODS: Diagnosis of MS was based on the MacDonald criteria. The cohort was divided into two groups based on their clinical course (multiple sclerosis with [n=8; 16 eyes] or without [n=7; 14 eyes] optic neuritis antecedents). The disease-free controls were matched for age and gender (n=15; 30 eyes). Retinal nerve fiber layer thickness was measured using optical coherence tomography (OCT; fastRNFL and RNFL thickness software protocol). Visual acuity, visual field, color vision were also noted. RESULTS: There were highly significant reductions (p<0.001) of retinal nerve fiber layer thickness in affected patients (with or without optic neuritis antecedents) compared with control eyes (fastRNFL and RNFL procedures). Visual acuity, visual field and color vision were globally less altered than OCT. There were no significant relationships among RNFL thickness and visual acuity, visual field, or color vision. CONCLUSION: This study has demonstrated the anatomic changes of the retinal nerve fiber layer of patients with multiple sclerosis with optic neuritis antecedents. Thus axonal loss following optic neuritis can be detected with OCT. But the retinal nerve fiber layer of patients without optic neuritis is also thinner than disease-free controls so that chronic optic axonal loss can be frequent in multiple sclerosis. Additionally, OCT was more sensitive than the common ophthalmological explorations to detect optical nerve impairment during multiple sclerosis. Finally, we demonstrated that two procedures fastRNFL and RNFL could be used to detect optic nerve impairment.     

Heterozygous loss of platelet glycoprotein (GP) Ib-V-IX variably affects platelet function in velocardiofacial syndrome (VCFS) patients

Velocardiofacial syndrome (VCFS) is a common, phenotypically heterogeneous developmental disorder caused by an interstitial microdeletion within human chromosome 22q11. The deleted chromosomal region in >90% of VCFS patients includes the GPIb beta gene, encoding for one subunit of the platelet GPIb-V-IX receptor, which is critical for platelet adhesion under shear, and important in aggregation and thrombin-mediated activation. Complete loss of GPIb-V-IX due to autosomal recessive inheritance of two GPIb alpha, Ib beta or GP9 gene mutations, results in a severe bleeding disorder, Bernard-Soulier syndrome (BSS). In this study, twenty-one confirmedVCFS patients were analyzed for platelet morphological and functional alterations, resulting from the heterozygous loss of one GPIb beta gene allele. Compared to unaffected family members, VCFS patients showed a significant decrease in platelet count; VCFS platelet size and mean platelet volume were increased, but not as markedly as in BSS. As expected from obligatory heterozygotes for GPIb beta deficiency, VCFS patients showed reduced platelet GPIb-V-IX surface expression and total GPIb content, but with considerable variation between cases. Platelet function tested using the PFA-100 trade mark analyzer was impaired in 70% of patients. Platelet aggregation was reduced in response to a GPIb-dependent agonist, ristocetin, in 50% of VCFS patients, with 35% showing a reduced response to thrombin receptor activating peptide. Genomic screening was performed to exclude mutations of the subunit genes, indicating that these platelet abnormalities were due to GPIb beta heterozygosity and not spontaneous BSS. In conclusion, many VCFS patients have in-vitro defects in platelet function that may increase their risk of bleeding during surgery.     

Elevated plasma levels of soluble platelet glycoprotein VI (GPVI) in patients with thrombotic microangiopathy

Background

Thrombotic microangiopathy (TMA) is caused by various conditions, such as decreased a ADAMTS13 level, activated or injured vascular endothelial cells or activated platelets. This study examined the soluble platelet glycoprotein VI (sGPVI) levels in patients with TMA to evaluate the activation of platelets in thrombotic states.

Materials and Methods

The plasma levels of sGPVI, ADAMTS13 activity, von Willebrand factor (VWF) and VWF propeptide (VWFpp) were measured in patients with TMA.

Results

The plasma levels of sGPVI were significantly higher in postoperative patients, patients with TMA and those with disseminated intravascular coagulation (DIC) than in those without thrombosis. The plasma levels of sGPVI were the highest in patients with TMA without markedly reduced ADAMTS13 and those were significantly reduced after plasma exchange.

Conclusion

The measurement of sGPVI level is therefore considered to be important for the diagnosis and evaluation of TMA.     

Circadian variations of platelet aggregability and fibrinolytic activity in healthy subjects

With a view to investigating whether in circadian variations of platelet aggregation (PA) and fibrinolytic activity there is an elevated risk period for incidence and development of ischemic stroke, 25 healthy subjects (5 females and 20 males), their age ranging from 29 to 51, were exposed to the analysis of PA, euglobulin lysis time (ELT), fibrinogen degradation products (FDP), antithrombin III (AT III) and heparin tolerance test (HTT) in blood samples drawn by venepuncture at 08.00, 11.00, 13.00, 15.00, 17.00 and 18.00 h; beside these intervals in the case of 10 healthy males, whose age ranged from 32 to 45, blood samples were taken at midnight as well. The group of 25 subjects comprised those who usually worked daily and nightly shifts, as well as those who were either at bed rest or doing their duties during daytime. The findings of this investigation have demonstrated that all the parameters studied exhibited circadian variations irrespective of sex, age or daily/nightly activities of the subjects. The most pronounced PA interval, which was not accompanied by corresponding increase of fibrinolytic activity, was that around 11.00 h and it is marked as the highest risk period for onset of ischemic stroke.     

The role of the Platelet Function Analyzer (PFA)-100 and platelet aggregometry in the differentiation of essential thrombocythemia from reactive thrombocytosis

Introduction

The most crucial component of all diagnostic criteria for essential thrombocythemia (ET) has been the exclusion of reactive thrombocytosis (RT). Our aim was to evaluate the diagnostic performance of the PFA-100 collagen-epinephrine (CEPI) cartridge test and epinephrine-induced aggregometry individually, but mainly combined, in the differentiation of ET from RT.

Materials and Methods

26 patients with ET and 25 with RT were studied. Platelet function was analyzed by the PFA-100 and by light transmission aggregometry with epinephrine and ADP. The JAK2 mutational status was identified and hematological parameters, plasma von Willebrand factor antigen and activity levels were also assessed.

Results

The sensitivity (Se), specificity (Sp), positive predictive value (PPV), and the negative predictive value (NPV) of PFA-100 CEPI vs epinephrine-induced aggregometry in the differentiation of ET from RT were estimated as follows: Se (%): 78.9 vs 84.6, Sp (%): 92.0 vs 96.0, PPV (%): 88.2 vs 95.7, NPV (%): 85.2 vs 85.7, respectively. When both of these methods were combined, a lower sensitivity of 68.4%, but a specificity of 100% was attained. The PPV observed with this double abnormal combination was 100% and the NPV 80.6%. Lastly, when we assessed the abnormality for either CEPI CT or epinephrine-induced aggregometry, the sensitivity was 100%, the specificity 88.0%, PPV 86.4% and NPV 100%. Thus, an abnormal combination was strongly suggestive of ET, while normal results with both methods excluded ET.

Conclusions

If our results are replicated by further studies, these two methods could be used very effectively as adjunct markers in the differentiation between ET and RT.     

Peripheral serotonergic markers in acutely suicidal patients. 1. Comparison of serotonergic platelet measures between suicidal individuals,nonsuicidal patients with major depression and healthy subjects

Summary Background. A robust association between “suicidality” and deficits of the serotoninergic neurotransmission has been claimed in the past. However, many studies having investigated the relationship between suicidality and peripheral indicators of serotoninergic neurotransmission suffer from considering only one or a very small number of potentially useful serotoninergic parameters, whereas a synoptic multidimensional approach appears to be more appropriate. Furthermore, the psychiatric context within which suicidal behaviour occurs should be considered when interpreting biochemical findings of patients with suicidal ideation and suicide attempts. Methods. In the present study 5 peripheral serotonergic markers, (platelet 5HT concentration, 5HT uptake activity, 5HT_2A receptor binding characteristics, MAO-B activity and tryptophan concentration in plasma) were assessed simultaneously. Of the 60 acutely suicidal inpatients (ICD-10: F43.xx, n = 52; F31/32/33, n = 8), 45 were suicide attempters. Data of 28 nonsuicidal patients with major depression (F31, n = 4; F32, n = 14; F33, n = 10) and 123 healthy volunteers represented the control groups. Results. Mean platelet 5HT concentration was significantly lower in suicidal inpatients when compared to nonsuicidal depressed patients, but did not differ from the figure in healthy subjects. Nonsuicidal depressed patients showed significantly higher mean platelet-5HT concentration than healthy controls. Mean V_max of 5HT uptake in washed platelets, but not in platelet-rich plasma, was significantly higher in suicidal patients than in healthy controls, not, however, when compared to nonsuicidal depressed patients. Mean K_D for the platelet 5HT_2A receptor and MAO-B activity were significantly lower in suicidal patients as compared to nonsuicidal depressed patients and healthy controls. The observed differences in peripheral serotonergic markers between groups are partially due to a significant gender effect. A lower MAO-B activity was observed only in suicidal females, while the higher V_max of 5HT uptake in washed platelets of suicidal patients was due to suicidal males. Conclusions. In view of conflicting observations made by other authors and the present findings on suicidal patients with adjustment disorder it remains doubtful whether and if so to which extent platelet studies can provide valid information on serotonergic mechanisms related to suicidal behaviour.     

Quantitation of amyloid-beta peptides in biological milieu using a novel homogeneous time-resolved fluorescence (HTRF) assay

Many of the recent advances in the understanding of the pathological processes underlying Alzheimer's disease have come about as a result of the development of assays that can specifically quantitate in biological milieu amyloid-beta (A beta) peptides ending at amino-acid positions Ala-42 (A beta(42)) and Val-40 (A beta(40)). The existing technologies, however, although proven in their utility are limited in their application with regards to sample manipulation and suitability for high-throughput screening. To overcome these limitations, in this report we describe the development of a novel homogeneous time-resolved fluorescence (HTRF) immunoassay for A beta(42) and A beta(40) peptides. This assay has the sensitivity, selectivity and dynamic range to allow specific, direct quantitation of A beta peptides in cell culture medium, plasma, cerebrospinal fluid and brain tissue extracts, and has the major advantage of minimising sample manipulation and its inherent inaccuracies.     

血小板膜糖蛋白CD41/CD61基因多态性及表达率与脑梗死的关系

目的探讨血小板膜糖蛋白CD41/CD61与脑梗死的关系。方法应用聚合酶链反应-限制性片断长度多态性分析技术(PCR-RFLP)和同步流式细胞术,分别检测CD41/CD61的基因多态性和表达率,并进行脑梗死组和对照组比较,其中脑梗死组115例:男64例,女51例,年龄36~77岁;对照组103例:男59例,女44例,年龄33~79岁。结果 (1)脑梗死组CD41 aa、ab和bb基因分布频率分别为20.0%、38.3%和41.7%,对照组分别为28.2%、48.5%和23.3%;两组间比较bb基因型有统计学意义(P<0.05);脑梗死组b等位基因频率(60.4%)高于对照组(47.6%),P<0.05。(2)CD61基因型均为aa型(未切开型)。(3)脑梗死组CD41/CD61表达率为96.0%±8%,对照组为85.5%±13%,差异有统计学意义(P<0.05)。(4)脑梗死组CD41 bb、aa基因型表达率分别为98.5%±13%、91.3%±8%,差异显著(P<0.05)。结论脑梗死与血小板膜糖蛋白CD41/CD61密切相关,CD41 bb基因影响CD41/CD61表达率;分析CD41基因多态性结合检测CD...     

Automatic analysis of surface EMG (preliminary findings in healthy subjects and in patients with neurogenic motor diseases)

Supramaximal electrical stimulation of a motor nerve produces a full contraction of a muscle and the corresponding compound action potential can be recorded. Recent studies appear to support the view that all the motor units are activated during voluntary maximal contraction, at least in the tibialis anterior muscle. The compound action potential and the EMG interference pattern in the tibialis anterior are regarded as two different manifestations of the activation of all the motor units. A method has been developed which compares these EMG activities, by automatic analysis, in order to obtain useful parameters for clinical applications.     

Quantitation of skin vasomotor control in normal subjects and in diabetic patients with autonomic neuropathy

Summary Peripheral autonomic neuropathy in diabetes has been difficult to evaluate. We have developed a test to quantitate sympathetic skin vasomotor function in the extremities. Skin vasomotor reflexes were investigated after warming and cooling the left arm and recording changes in skin temperature as a measure of skin blood flow in the right hand and both feet. Twenty-three diabetic patients with cardiac autonomic neuropathy and 28 healthy control subjects were examined. In contrast to the healthy subjects, the diabetic patients showed reduced or even absent responses in skin temperature to both warming and cooling. The rate of skin temperature decrease for the hand and feet during cooling, which was used as the actual parameter to quantitate skin vasomotor control, was significantly reduced in the diabetic group as compared with the healthy control subjects. We conclude that this technique provides a simple non-invasive method for quantitating skin vasomotor function in the extremities of diabetic patients.     

Nocturnal growth hormone secretion in schizophrenic patients and healthy subjects.

Plasma growth hormone concentrations were measured at hourly intervals between 10 p.m. and 8 a.m. the next morning in 15 drug-free chronic schizophrenic male inpatients and 14 healthy males. Growth hormone secretion was significantly lower in the patients as compared with the controls. Growth hormone release peaked around 1 a.m. in the controls, but a growth hormone peak was absent in the patient group. Increased dopamine activity, increased serotonin activity, or both could explain the absence of a nocturnal growth hormone surge in the schizophrenic patients.     

Measurement of GPV released by activated platelets using a sensitive immunocapture ELISA--its use to follow platelet storage in transfusion.

Thrombin, the most potent platelet agonist, plays a central role in haemostasis and in the occurrence of thrombotic events. This agonist activates platelets by cleaving the PAR G-protein coupled receptors and by binding to glycoprotein (GP) Ib and also cleaves GPV at the platelet surface to liberate the soluble 69 kDa fragment GPVf1. Monoclonal antibodies (MoAbs) to GPV were developed as tools to study the mechanism of platelet GPV cleavage and measure release of GPV in pathological situations. Specificity of the MoAbs for GPV was confirmed by flow cytometry and immunoprecipitation of proteins from human platelets and Dami megakaryocytic cells. A sensitive immunocapture sandwich ELISA for soluble GPV was developed using two MoAbs recognizing different epitopes of GPV and purified platelet or recombinant GPV as reference protein. This ELISA was employed to determine the mean plasma concentration of GPV in 100 normal individuals (17.3 ng/ml), to demonstrate the dose-dependent release of GPVf1 from washed platelets stimulated with thrombin and to follow the progressive release of GPVf1 during storage of therapeutic platelet concentrates. The present report describes a sensitive GPV ELISA of direct application to survey the processing and storage of platelet concentrates for transfusion and of potential value to monitor platelet activation in thrombotic states.     

Actigraphy in patients with seasonal affective disorder and healthy control subjects treated with light therapy.

BACKGROUND: Abnormalities of the circadian rest-activity cycle are hypothesized to accompany the clinical picture of seasonal affective disorder (SAD). The purpose of this study was to investigate if bright light therapy (BLT) is able to reverse these disturbances. METHODS: Seventeen SAD outpatients and 17 sex- and age-matched healthy control subjects were treated with BLT administered in the morning for 4 weeks. Activity levels were measured with wrist actigraphy. RESULTS: SAD patients had 33% lower total (p = .031) and 43% lower daylight activity (p = .006) in week 1 compared with control subjects. The relative amplitude of the sleep-wake cycle was attenuated by 6% in patients (p = .025); they were phase delayed by 55 minutes (p = .023) and had significantly lower sleep efficiency (p = .030). Total (p = .002) and daylight activity (p = .001) increased after 4 weeks of treatment in SAD patients. Moreover, BLT led to increase of relative amplitude (p = .005), advance of delayed rhythms (p = .036), and improved sleep efficiency (p = .011) in patients. Intradaily stability, measuring the strength of coupling of the rhythm to external zeitgebers, increased by 9% both in patients and healthy control subjects (p = .032). CONCLUSIONS: Treatment with BLT normalizes disturbed activity patterns and restores circadian rhythms in SAD patients. BLT might also stabilize the circadian rhythm in nondepressed individuals during the fall-winter season.     

Neuroendocrine effects of intravenous clomipramine in depressed patients and healthy subjects.

OBJECTIVE: Neuroendocrine challenge paradigms have been used to asses serotonergic systems in depression, but limitations in the specificity of many of these tests have been noted. In this study, the neuroendocrine responses to acute intravenous administration of the serotonin (5-HT) reuptake inhibitor clomipramine were assessed in depressed patients and matched control subjects. METHODS: Thirty hospitalized patients who met DSM-III-R criteria for major depression, and 30 healthy control subjects who were matched for age, sex, and season of year for the time of study, received 12.5 mg of intravenously administered clomipramine. RESULTS: The depressed patients demonstrated significant blunting of prolactin responses to clomipramine, as well as trends toward blunted ACTH and cortisol responses. There was no difference between the patient and control groups in growth hormone responses, plasma clomipramine levels, or self-reports of side effects. CONCLUSIONS: These data support the hypothesis that depressed patients have abnormal neuroendocrine responses to the intravenous administration of the 5-HT reuptake inhibitor clomipramine. Further study is required to delineate the mechanisms responsible for the abnormal response to intravenously administered clomipramine in depression.