Pleocytosis in cerebrospinal fluid attributed to ischemic stroke: A review of the literature

INTRODUCTION

Lumbar puncture is generally performed in stroke settings when infectious or inflammatory diseases are suspected to be the etiology. This review aimed to assess the prevalence of pleocytosis in the cerebrospinal fluid following ischemic stroke without inflammatory or infectious etiology.

METHODS

We searched PubMed for studies with mentions of "[ischemic stroke] AND [cerebrospinal fluid]". We included only studies written in English, including patients with a primary diagnosis of either ischemic stroke or transient ischemic attack (TIA), and where white blood cell count in the spinal fluid was presented. Studies investigating common etiologies for pleocytosis, was excluded. Study and patient characteristics, white blood cell count and time to lumbar puncture were presented in tables, and the prevalence of pleocytosis were reported and plotted graphically.

RESULTS

We included 15 studies with 1607 patients, 1522 with ischemic stroke and 85 with TIA. The prevalence of pleocytosis was between 0% to 28,6% and a mean of 11.8%. The highest white blood cell count found with common etiologies for pleocytosis ruled out was 56 cells/mm3. A mean white blood cell count of 4.0 was based on the three studies where this was available.

DISCUSSION

The included studies were methodologically heterogenous and few had pleocytosis as primary outcome. Pleocytosis following ischemic stroke is uncommon and should prompt further investigations.

Clinical outcomes of light therapy in hospitalized patients - A systematic review

Light therapy and the effects on biological function have been known and investigated for decades. Light therapy is used to compensate for the lack of exposure to sunlight, which is thought to be linked to major depressive disorder with seasonal patterns. It is applied as sessions with bright light mimicking natural sunlight. Lack of bright light during daytime is not the only factor to maintain the circadian rhythm, also lack of exposure to bright light at night is important. A new modality called naturalistic light shows promise, mimicking daylight by dynamically changing intensity and wavelengths throughout the day. Evidence of clinical effects, besides bright light effects on depression, is still limited, especially in hospital populations, and present review aims to extract results of the effect of any optical light intervention on hospitalized patients. Through database search, 29 trials were included, of which 8 trials used a variation of naturalistic light. Trials were heterogeneous regarding designs, populations, interventions, methods and outcomes. In 14 out of 17 studies investigating sleep duration, quality and circadian alignment, along with decreased fatigue and improved mood in daytime, light therapy had a significant effect. Circadian rhythm and rhythmicity were affected as well. The effect on mood and cognition was inconsistent across studies. Trials showed more significant outcomes when conducted in non-intensive care units and with duration >5 days. Lux was reported in and compared across 24 studies and did not appear to be correlated to outcome, rather the distribution of wavelengths should be considered when conducting trials in the future. Of the 8 trials investigating naturalistic light, 4 trials had significant outcomes and 3 had adverse outcomes compared to one in the standard light regime. The overall effect of light therapy is beneficial, but evidence for the effect of naturalistic light is still insufficient to be recommended before other modalities. Future research in this area should be conducted in facilities where naturalistic light is installed, with a focus on the spectral distribution.

Impact of the circadian clock on fibrinolysis and coagulation in healthy individuals and cardiovascular patients - A systematic review

INTRODUCTION

Human body functions exhibit a circadian rhythm generated in peripheral cells and synchronized by the suprachiasmatic nucleus (SCN), which mostly is entrained by the daily light/dark cycles. Activity, meals and posture are capable of interfering with the endogenous circadian rhythm of coagulation parameters. An increasing number of human disorders show a circadian component, and epidemiological studies find cardiovascular events to peak in the morning hours. The aim was to review the circadian rhythms impact on fibrinolysis and coagulation in healthy individuals and cardiovascular patients.

MATERIALS AND METHODS

A total number of 25 studies were identified where 8 enrolled cardiovascular patients with or without healthy individuals. Using a MeSH-search in MEDLINE PubMed. Only original peer-reviewed papers were included.

RESULTS

Results showed substantial variance with respect to exhibition of circadian rhythms and/or peak/trough times. Circadian rhythms of fibrinolysis were less pronounced in cardiovascular patients than in healthy individuals with decreased levels in the morning hours compared to healthy inducing higher risk of blood clotting.

CONCLUSIONS

Because of small studied group sizes and failure to control for entraining factors, larger studies are needed to fully establish the effects of the circadian rhythm on especially coagulation. The findings of chronobiologic rhythms in coagulation and fibrinolysis could suggest a need for a chrono-pharmacological approach when treating/preventing cardiovascular diseases.

The Effects of Naturalistic Light on Diurnal Plasma Melatonin and Serum Cortisol Levels in Stroke Patients during Admission for Rehabilitation: A Randomized Controlled Trial

Background: Stroke patients admitted for rehabilitation often lack sufficient daytime blue light exposure due to the absence of natural light and are often exposed to light at unnatural time points. We hypothesized that artificial light imitating daylight, termed naturalistic light, would stabilize the circadian rhythm of plasma melatonin and serum cortisol levels among long-term hospitalized stroke patients. Methods: A quasi-randomized controlled trial. Stroke patients in need of rehabilitation were randomized between May 1, 2014, and June 1, 2015 to either a rehabilitation unit equipped entirely with always on naturalistic lighting (IU), or to a rehabilitation unit with standard indoor lighting (CU). At both inclusion and discharge after a hospital stay of at least 2 weeks, plasma melatonin and serum cortisol levels were measured every 4 hours over a 24-hour period. Circadian rhythm was estimated using cosinor analysis, and variance between time-points. Results: A total of 43 were able to participate in the blood collection. Normal diurnal rhythm of melatonin was disrupted at both inclusion and discharge. In the IU group, melatonin plasma levels were increased at discharge compared to inclusion (n = 23; median diff, 2.9; IQR: -1.0 to 9.9, p = 0.030) and rhythmicity evolved (n = 23; p = 0.007). In the CU group, melatonin plasma levels were similar between discharge and inclusion and no rhythmicity evolved. Overall, both patient groups showed normal cortisol diurnal rhythms at both inclusion and discharge. Conclusions: This study is the first to demonstrate elevated melatonin plasma levels and evolved rhythmicity due to stimulation with naturalistic light.

The isolation and properties of the skin-reactive substance in Aedes aegypti oral secretion

The skin-reactive substance present in the oral secretion of Aedes aegypti mosquitos was isolated by gel filtration chromatography and found to be a protein of high molecular weight designated as F-1. Amino acid analysis of the protein revealed relatively high proportions of glycine (34%) and proline (11%). The active fraction contained 9% carbohydrate and less than 1% amino sugar, sialic acid, or phosphorus. A random coil structure was suggested for F-1 on the basis of optical rotation and infrared data. A linear relation was established between the diameter of the immediate skin reaction and the logarithm of the weight of F-1 injected. F-1 was completely inactivated by incubation at pH 2.5. A low molecular weight fraction was separated from inactivated F-1 and its amino acid composition was determined.

Gel filtration of insect haemolymph proteins

Haemolymph from 6th instar larvae of Malacosoma americanum and 5th instar nymphs of Locusta migratoria was subjected to gel filtration on Sephadex G-200. Three protein fractions were produced in each case. Each fraction was analyzed for protein content and assayed for esterase and tyrosinase activity. The degree of resolution obtained by gel filtration was tested by Polyacrylamide "disc" electrophoresis. Each fraction displayed a specific type of enzyme activity and protein composition. The similarities between the haemolymph proteins of the two insects are discussed.