Melatonin at repeated doses alleviates hyperglycemia-exacerbated cerebral ischemia-reperfusion injury at 72 h via anti-inflammation and anti-apoptosis

Objective

We aimed to investigate how hyperglycemia would exacerbate cerebral ischemia-reperfusion injury (CIRI) in a rat model of type 1 diabetes mellitus (T1DM) and explore the beneficial effects of multiple doses of melatonin in T1DM induced CIRI.

Method

The T1DM rat model was induced with streptozocin, and melatonin (10 mg/kg) was injected at 0.5 h before ischemia as well as at 24 and 48 h after reperfusion.

Results

When compared to normoglycemic (NG) rats, T1DM rats had hyperglycemia with weight loss before CIRI. Despite comparable degrees of ischemia and initial reperfusion, T1DM rats tended to have greater weight loss and had worse neurological deficits and larger infarct volume than NG rats up to 72 h after CIRI. Persistent activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway but not of apoptosis or calpains was a crucial factor in T1DM-mediated exacerbation of CIRI at 72 h. Despite lacking effects on baseline hyperglycemia, ischemia and initial reperfusion, melatonin at multiple doses lessened post-CIRI weight loss, neurological deficits and infarct volume in T1DM rats at 72 h. when compared to vehicle-treated T1DM rats with CIRI. Beneficial effects of melatonin treatment included decreased activation of NF-κB pathway, apoptosis and calpains, leading to reduced expression of inducible nitric oxide synthase and enhanced neuronal density.

Conclusion

Melatonin at multiple doses can alleviate T1DM-mediated exacerbation of CIRI at 72 h through anti-inflammation and anti-apoptosis.

Melatonin mitigates type 1 diabetes-aggravated cerebral ischemia-reperfusion injury through anti-inflammatory and anti-apoptotic effects

INTRODUCTION

Cerebral ischemia and diabetes mellitus (DM) are common diseases that often coexist and interact with each other. DM doubles the risk of ischemic stroke, and cerebral ischemia causes stress-induced hyperglycemia. Most experimental stroke studies used healthy animals. Melatonin is neuroprotective against cerebral ischemia-reperfusion injury (CIRI) in non-DM, normoglycemic animals through anti-oxidant effect, anti-inflammation, and anti-apoptosis. Previous studies have also reported a negative correlation between hyperglycemia and urinary melatonin metabolite.

OBJECTIVES

The present study investigated the effects of type 1 DM (T1DM) on CIRI in rats and the role of melatonin against CIRI in T1DM animals.

RESULTS

Our results revealed that T1DM aggravated CIRI, leading to greater weight loss, increased infarct volume, and worse neurological deficit. T1DM aggravated the post-CIRI activation of nuclear factor kappa B (NF-κB) pathway and increase in pro-apoptotic markers. A single intraperitoneal injection of melatonin at 10 mg/kg given 30 min before ischemia onset attenuated CIRI in T1DM rats, resulting in less weight loss, decreased infarct volume, and milder neurological deficit when compared with the vehicle group. Melatonin treatment achieved anti-inflammatory and anti-apoptotic effects with reduced NF-κB pathway activation, reduced mitochondrial cytochrome C release, decreased calpain-mediated spectrin breakdown product (SBDP), and decreased caspase-3-mediated SBDP. The treatment also led to fewer iNOS+ cells, milder CD-68+ macrophage/microglia infiltration, decreased TUNEL+ apoptotic cells, and better neuronal survival.

CONCLUSIONS

T1DM aggravates CIRI. Melatonin treatment is neuroprotective against CIRI in T1DM rats via anti-inflammatory and anti-apoptotic effects.

Inhibitory dysfunction may cause prospective memory impairment in temporal lobe epilepsy (TLE) patients: an event-related potential study

Introduction

Prospective memory (PM) is the ability to remember future intentions, and PM function is closely related to independence in daily life, particularly in patients with temporal lobe epilepsy (TLE). As PM involves various cognitive components of attention, working memory, inhibition and other executive functions, this study investigated how TLE may affect PM components and the underlying neural mechanisms.

Methods

Sixty-four subjects were recruited, including 20 refractory TLE patients, 18 well-controlled TLE patients and 26 age-matched healthy controls. A set of neuropsychological tests was administered to assess specific brain functions. An event-related potential (ERP) task was used to further explore how PM and its components would be differentially affected in the two TLE types.

Results

Our findings revealed that: (1) refractory TLE patients scored lower than the healthy controls in the digit span, Verbal Fluency Test and Symbol Digit Modalities Test; (2) refractory TLE patients exhibited impaired PM performance and reduced prospective positivity amplitudes over the frontal, central and parietal regions in ERP experiments when compared to the healthy controls; and (3) decreased P3 amplitudes in the nogo trials were observed over the frontal-central sites in refractory but not in well-controlled TLE patients.

Discussion

To our knowledge, this is the first ERP study on PM that has specifically identified PM impairment in refractory but not in well-controlled TLE patients. Our finding of double dissociation in PM components suggests that inhibition dysfunction may be the main reason for PM deficit in refractory TLE patients. The present results have clinical implications for neuropsychological rehabilitation in TLE patients.

Evaluation of the Cognitive Performance of Hypertensive Patients with Silent Cerebrovascular Lesions

Evidence accumulated from the last decade has proven that silent cerebrovascular lesions (SCLs) and their underlying pathogenic processes contribute to cognitive decline in the elderly. However, the distinct effects of each type of the lesions on cognitive performance remain unclear. Moreover, research data from Chinese elderly with SCLs is scarce. In this study, 398 otherwise healthy hypertensive elderly subjects (median age 72 years) were included and assessed. All participates were required to complete a battery of structured neuropsychological assessment, including forward and backward digit span tests, symbol digit modalities test, Stroop test, verbal fluency test and Montreal Cognitive Assessment. These tests were used to assess attention, executive function, information processing speed, language, memory and visuospatial function. A multi-sequence 3T MRI scanning was arranged within one month of the neuropsychological assessment to evaluate the burden of SCLs. SCLs were rated visually. Cerebral microbleeds (CMBs) and silent lacunes (SLs) were identified as strictly lobar CMBs and SLs or deep CMBs and SLs according to their locations, respectively. Similarly, white matter hyperintensities (WMHs) were separated into periventricular WMHs (PVHs) and deep WMHs (DWMHs). A series of linear regression models were used to assess the correlation between each type of SCLs and individual cognitive function domain. The results showed that CMBs tend to impair language-related cognition. Deep SLs affect executive function, but this association disappeared after controlling for other types of SCLs. PVHs, rather than DWMHs, are associated with cognitive decline, especially in executive function and processing speed. It is concluded that different aspects of SCLs have differential impact on cognitive performance in hypertensive elderly Chinese.

Electrophysiological Study on Cognitive Function in Systemic Lupus Erythematosus Patients With Previous Neuropsychiatric Involvement

This study aimed to evaluate P300 as an electrophysiological marker of cognitive function in patients with systemic lupus erythematosus (SLE) who had previous neuropsychiatric (NPSLE) involvement and were diagnosed to have cognitive impairment by standard neuropsychological tests. Event-related potentials (ERPs) were assessed by the auditory and visual oddball paradigms. Amplitude and latency of P300 at the frontal (Fz), central (Cz), and parietal (Pz) regions were determined and compared with controls. P300 detection was performed in NPSLE patients with pre-diagnosed cognitive impairment (n = 9), matched SLE patients without previous NPSLE (non-NPSLE) (n = 9), and healthy controls (n = 15). Auditory oddball task did not show any P300 abnormality between groups. Visual oddball task revealed reduced amplitude of P300 over Fz ( P = .002) and Cz ( P = .009) electrodes in NPSLE patients compared with healthy controls and among those who had predominant memory deficit ( P = .01 at Fz). Abnormal P300 was also observed in non-NPSLE patients at Fz and Cz. Using visual oddball paradigm, abnormal P300 was found in NPSLE patients over frontal and parietal regions compared with normal controls but was not discriminative from possible subclinical disease in non-NPSLE patients. In conclusion, visual oddball paradigm was a more sensitive electrophysiological marker than auditory oddball paradigm for cognitive impairment in NPSLE patients.

Total small vessel disease score and risk of recurrent stroke: Validation in 2 large cohorts

Objective:

In patients with TIA and ischemic stroke, we validated the total small vessel disease (SVD) score by determining its prognostic value for recurrent stroke.

Methods:

Two independent prospective studies were conducted, one comprising predominantly Caucasian patients with TIA/ischemic stroke (Oxford Vascular Study [OXVASC]) and one predominantly Chinese patients with ischemic stroke (University of Hong Kong [HKU]). Cerebral MRI was performed and assessed for lacunes, microbleeds, white matter hyperintensities (WMH), and perivascular spaces (PVS). Predictive value of total SVD score for risk of recurrent stroke was determined and potential refinements considered.

Results:

In 2,002 patients with TIA/ischemic stroke (OXVASC n = 1,028, HKU n = 974, 6,924 patient-years follow-up), a higher score was associated with an increased risk of recurrent ischemic stroke (adjusted hazard ratio [HR] per unit increase: 1.32, 1.16–1.51, p < 0.0001; c statistic 0.61, 0.56–0.65, p < 0.0001) and intracerebral hemorrhage (ICH) (HR 1.54, 1.11–2.13, p = 0.009; c statistic 0.65, 0.54–0.76, p = 0.006). A higher score predicted recurrent stroke in SVD and non-SVD TIA/ischemic stroke subtypes (c statistic 0.67, 0.59–0.74, p < 0.0001 and 0.60, 0.55–0.65, p < 0.0001). Including burden of microbleeds and WMH and adjusting the cutoff of basal ganglia PVS potentially improved predictive power for ICH (c statistic 0.71, 0.60–0.81, p_het = 0.45), but not for recurrent ischemic stroke (c statistic 0.60, 0.56–0.65, p_het = 0.76) on internal validation.

Conclusions:

The total SVD score has predictive value for recurrent stroke after TIA/ischemic stroke. Prediction of recurrence in patients with nonlacunar events highlights the potential role of SVD in wider stroke etiology.

Visit-to-visit blood pressure variability as a prognostic marker in patients with cardiovascular and cerebrovascular diseases--relationships and comparisons with vascular markers of atherosclerosis

BACKGROUND

Visit-to-visit blood pressure variability (BPV) is a simple surrogate marker for the development of atherosclerotic diseases, cardiovascular and all-cause mortality. Nevertheless, the relative prognostic value of BPV in comparison with other established vascular assessments remain uncertain.

METHODS

We prospectively followed-up 656 high-risk patients with diabetes or established cardiovascular or cerebrovascular diseases for the occurrence of major adverse cardiovascular events (MACEs). Baseline brachial endothelial function, carotid intima-media thickness (IMT) and plaque burden, ankle-brachial index and arterial stiffness were determined. Visit-to-visit BPV were recorded during a mean 18 ± 9 outpatient clinic visits.

RESULTS

After a mean 81 ± 12 month's follow-up, 123 patients (19%) developed MACEs. Patients who developed a MACE had significantly higher systolic BPV, more severe endothelial function, arterial stiffness and systemic atherosclerotic burden compared to patients who did not develop a MACE (all P<0.01). BPV significantly correlated with all of the vascular assessments (P<0.01). A high carotid IMT had the greatest prognostic value in predicting development of a MACE (area under receiver operating characteristic curve (AUC) 0.69 ± 0.03, P<0.01). A high BPV also had moderate prognostic value in prediction of MACE (AUC 0.65 ± 0.03, P<0.01). After adjustment of confounding factors, a high BPV remained a significant independent predictor of MACE (hazards ratio 1.67, 95% confidence interval 1.14-2.43, P<0.01).

CONCLUSIONS

Compared with established surrogate markers of atherosclerosis, visit-to-visit BPV provides similar prognostic information and may represent a new and simple marker for adverse outcomes in patients with vascular diseases.

Visit-to-visit systolic blood pressure variability predicts all-cause and cardiovascular mortality after lacunar infarct

BACKGROUND AND PURPOSE

Both blood pressure (BP) and its variability (BPV) are established risk factors for development of atherosclerotic disease and are associated with an increased risk for cardiovascular and all-cause mortality. The prognostic implications of outpatient clinic visit-to-visit BPV amongst patients with lacunar infarction are nevertheless unknown.

METHODS

The clinical outcome of 281 patients with lacunar infarction was prospectively followed up. The average BP and BPV, as determined by the standard deviation of the systolic and diastolic BP, were recorded during a mean 13 ± 6 outpatient clinic visits.

RESULTS

The mean age of the population was 70 ± 10 years. After a mean 78 ± 18 months follow-up, 65 patients died (23%), 31% (20/65) due to cardiovascular causes; 14% and 7% developed recurrent stroke and acute coronary syndrome. After adjusting for age, sex, mean systolic and diastolic BP, cardiovascular risk factors and comorbidities, patients with a systolic BPV of the third tertile had significantly higher risk of all-cause mortality [hazard ratio (HR) 1.97, 95% confidence interval (CI) 1.02-3.80, P = 0.04) and cardiovascular mortality (HR 7.64, 95% CI 1.65-35.41, P < 0.01) than those with systolic BPV of the first tertile. Nevertheless, systolic BPV did not predict recurrent stroke or acute coronary syndrome. Diastolic BPV did not predict various adverse clinical outcomes.

CONCLUSIONS

Visit-to-visit systolic BPV predicts long-term all-cause and cardiovascular mortality after lacunar infarct, independent of conventional risk factors including average BP control.

Increased prospective memory interference in normal and pathological aging: different roles of motor and verbal processing speed

This is a study on prospective memory (PM) and the PM interference effect in normal and pathological aging. One hundred and seven subjects, including 41 healthy young adults, 40 non-demented older adults and 26 patients with mild Alzheimer's disease (AD) participated in this study using a laboratory event-based PM task. PM task performance was comparable between the non-demented older and young adults, but impaired in the AD patients. The PM interference effect increased progressively from the healthy young adults, the non-demented older adults, to the AD patients. Path analysis revealed that the possible mechanism mediating the increased PM interference was the slow motor processing speed in normal aging, while it was the slow verbal speed in pathological aging. It is suggested that different neuropsychological mechanisms may underpin the affected performance of PM task in normal and pathological aging.

An fMRI study showing the effect of acupuncture in chronic stage stroke patients with aphasia

Acupuncture is used as a treatment in stroke patients with aphasia, yet the underlying neural mechanisms are unknown. This study aims to examine the relationship between changes in language function and brain activation using functional magnetic resonance imaging in chronic stroke patients with aphasia who underwent an 8-week acupuncture protocol. Seven chronic stroke patients were identified from a stroke database of a regional acute hospital in Hong Kong between January and July 2007. Patients were treated three times a week over a period of 8 weeks. Four acupoints were stimulated on the weak side of the patient's body. No other rehabilitation was given during the study period. Changes in language function were measured by aphasia quotient (AQ) of Cantonese Aphasia Battery (CAB). Functional magnetic resonance imaging blood oxygen level dependent signals were used to demonstrate the correlation between changes in AQ and brain activation after treatment. The patients were divided into well-recovered and poorly- recovered groups based on their CAB scores at entry. The well-recovered group showed significant improvement in CAB scores after receiving acupuncture treatment. A significant correlation between changes in AQ and blood oxygen level dependent activation in the lesioned Wernicke's speech area was found. These preliminary results suggest that acupuncture may be beneficial to language recovery in chronic stroke patients.

Production and validation of Putonghua- and Cantonese-Chinese language National Institutes of Health Stroke Scale training and certification videos

BACKGROUND AND PURPOSES

The National Institutes of Health Stroke Scale (NIHSS) is an integral part of acute stroke assessment. We report our experience with new Putonghua- and Cantonese-Chinese language NIHSS (PC-NIHSS and CC-NIHSS) training and certification videos.

METHODS

A professional video production company was hired to create the training and certification videos for both PC-NIHSS and CC-NIHSS. Two training and certification workshops were held in Chengdu and Beijing, and two workshops in Hong Kong. The instruction, training and group A certification videos were presented to workshop attendees. Unweighted kappa statistics were used to measure the agreement among raters, and the inter-rater agreements for PC-NIHSS and CC-NIHSS videos were compared with those of original English language NIHSS (E-NIHSS) videos.

RESULTS

The pass rates using PC-NIHSS and CC-NIHSS videos were 79% and 82%, respectively. All possible responses on individual scale items were included. Facial palsy and limb ataxia (13%) showed poor agreement, nine (60%) to 10 (67%) items showed moderate agreement (0.4<kappa<0.75), and three (20%) to four (27%) items showed excellent agreement. When compared with E-NIHSS videos, the agreements on best gaze, visual fields, facial weakness and aphasia were less for PC-NIHSS videos, and the agreements on commands for level of consciousness and visual fields were less for CC-NIHSS videos. Nevertheless, there was no difference between PC-NIHSS or CC-NIHSS and E-NIHSS videos in the agreement on total score.

CONCLUSIONS

Compared with E-NIHSS videos, PC-NIHSS and CC-NIHSS videos show good content validity and inter-rater reliability. Availability of these videos may facilitate the proper use of NIHSS among physicians and nurses in Putonghua- or Cantonese-speaking communities.

Depression literacy among Chinese stroke survivors

OBJECTIVES

Mental health literacy is fundamental to the pursuit of health. Little is known about patients' literacy levels regarding depression even though it is common among elderly stroke survivors. This paper will report the level of mental health literacy and thematic constructs of depression interpreted by a group of stroke survivors.

METHOD

Qualitative data on patients' understanding of 'depression' in Chinese were translated and analyzed by an academic and a researcher separately to identify emerging constructs using a thematic approach. Out of 214 ischemic stroke older adults, aged 50+, 85 were able to explain the term in their own words after their first stroke attack.

RESULTS

The majority of stroke patients (60%, 129 out of 214) had never heard of depression and only four referred to it as a medical disease. Only a third would like to learn more about depression. Older Chinese adults depicted depression mainly by using words in the cognitive and affective domains, but the descriptors used were mostly non-specific and might not match the diagnostic criteria for depression or the commonly used screening tools.

CONCLUSION

Low mental health literacy among older patients indicated that much more work needs to be done in health promotion and education on depression literacy.

New-onset constipation at acute stage after first stroke: incidence, risk factors, and impact on the stroke outcome

BACKGROUND AND PURPOSE

The prevalence of constipation after stroke varies from 30% to 60%. The incidence of new-onset constipation during the early stage of stroke remains uncertain. The present study was designed to investigate the prevalence of new-onset constipation, its risk factors, and its impact on stroke outcome in patients with their first stroke at acute stage.

METHODS

This is a prospective cohort study of 154 patients admitted with their first stroke. New-onset constipation during the first 4 weeks of stroke was recorded, using the Rome II criteria for constipation. Demographics, characteristics of the stroke, laboratory parameters, and use of medications were evaluated as risk factors for constipation. Death, recurrent stroke, and handicap at 12 weeks were regarded as poor outcome. The impact of constipation on poor outcome was also studied.

RESULTS

The cumulative incidence of new-onset constipation was 55.2% at 4 weeks poststroke. The occurrence of constipation was associated with dependence (P<0.01) and use of bedpan for defecation (P<0.05). Among patients with moderate stroke severity (NIHSS 4 to 11) at baseline, constipation at 4 weeks was associated with a poor outcome at 12 weeks.

CONCLUSIONS

New-onset constipation is a common complication of acute stroke. Its occurrence is associated with dependence and use of bedpan for defecation. Its development may predict a poor outcome at 12 weeks in patients with moderately severe stroke.

The smiley as a simple screening tool for depression after stroke: A preliminary study

In Hong Kong, there is a paucity of evidence to support which tool is superior in measuring depression after stroke (DAS). A simple, non-language-based, culturally neutral, non-verbal and easy to apply tool that is not highly dependent on training will be desirable.

OBJECTIVES

The present study aimed to examine the clinical utility of three smiley pictures in detecting DAS for older Chinese patients at 1 month after first-ever ischemic stroke.

METHODS

This was a cross-sectional study. A total of 253 stroke patients were interviewed by a research nurse at 1-month follow-up.

RESULTS

Taking Diagnostic and Statistic Manual (DSM IV) as the gold standard, the measurement properties of emoticon (sad) in terms of sensitivity, specificity, positive and negative predictive values, as well as Kappa's value were found comparable to Geriatric Depression Scale (GDS). The emoticon (happy) demonstrated a highly significant inverse relationship with all depression assessment tools (p<0.001). It was also found that the emoticon (flat) could capture 98% of all depressed subjects identified by DSM IV, although its predictive values were less satisfactory.

CONCLUSIONS

The smiley pictures seemed to fulfil the requirements for early and prompt screening among older patients. Cultural implication regarding emotions dissipation among Chinese patients should be further studied.

Nonthymoma early-onset- and late-onset-generalized myasthenia gravis—A retrospective hospital-based study

OBJECTIVE

Acquired myasthenia gravis (MG) is predominantly due to nicotinic acetylcholine receptor (AChR) autoantibodies (Ab). Differences between nonthymoma early-onset and late-onset MG were reported. We studied the clinical and serological characteristics of nonthymoma AChR Ab-positive-generalized MG patients.

PATIENTS AND METHODS

Chinese AChR Ab-positive-generalized MG patients who had generalized disease for 3 years or longer were studied.

RESULTS

Among 41 such patients, 25 (61%) were female. The mean onset age was 43.5 years (range 9-78 years) and the mean follow-up duration was 7.8 years (range 3-20 years). Sixteen (39%) patients had late-onset disease (onset age >or=50 years). Compared to early-onset patients (onset age <50 years), late-onset patients were characterized by male predominance (p=0.002), absence of thymic lymphofollicular hyperplasia (p=0.036), and a higher striated muscle Ab seropositivity rate (94% versus 4%, p<0.001). Although there was no statistically significant difference in clinical severity and outcome or response to treatment between late-onset and early-onset patients, 50% and 75% of late-onset patients had moderate or severe disease at onset and worst status, respectively, compared to 28% and 52% for early-onset patients at onset and worst status, respectively. Also 63% of late-onset patients had disease progressed within first 3 years compared to only 40% of early-onset patients did.

CONCLUSION

Nonthymoma late-onset-generalized MG patients were common among Hong Kong Chinese, with a statistically non-significant trend that it was clinically more severe than early-onset MG but with similar clinical outcome or response to treatment; >90% of these patients were seropositive for striated muscle Ab.

Update on medical and surgical management of intracerebral hemorrhage

Intracerebral hemorrhage (ICH) accounts for 15% of all strokes in the US and Europe and 20% to 30% in Asian populations. ICH is associated with a higher morbidity, disability and mortality than ischemic strokes. Primary ICH originates from spontaneous rupture of small arteries and arterioles previously damaged by chronic hypertension or amyloid angiopathy. Secondary ICH is associated with underlying vascular abnormalities or other pathologies. Manifestation is acute with focal neurological signs and features of raised intracranial pressure. Despite our improved understanding of the pathophysiology of hematoma expansion and edema formation, management is primarily supportive, and outcomes remain poor. A recently published report has confirmed that there is no overall benefit from early surgery when compared with initial conservative treatment. In contrast, treatment with recombinant activated factor VII within 4 hours of onset limits hematoma growth at 24 hours, and reduces mortality and improves functional outcomes at 90 days. Several ICH scoring methods have recently been proposed for better prediction of outcome. These scoring methods may be useful in selecting suitable patients for clinical trials. Microbleeds are commonly seen on magnetic resonance imaging. Further studies are awaited to clarify the association between microbleeds and the future risk of ICH.

Incidence and predictors of depression after stroke (DAS)

Objective. Depression after stroke (DAS) poses a treble burden to patients, families and health care system. The purpose of this paper is to estimate the incidence of depression among first-ever ischemic stroke patients and identify the predictors of DAS. Methods. A longitudinal study design was undertaken. Of 836 patients admitted to the stroke unit of two regional hospitals in Hong Kong during the period 1 June 2004 to 31 May 2005, 295 patients fulfilled the inclusion and exclusion criteria. A total of 260 patients had given their consents and were interviewed at 1 month after stroke onset. Results. Nearly one-quarter of the first ischemic stroke patients, who were known to be free of personal and family history of psychiatric illnesses, were found to satisfy the criteria of depression using Diagnostic and Statistical Manual IV (24%, 48 out of 200 participants; 95% CI: 18.6%, 30.4%). This result was close to that assessed by the Geriatric Depression Scale (GDS) - 15 items. The psycho-emotional factor and level of dependency were found to be most significant predictors for DAS onset. Conclusion. The high incidence of DAS and low rate of accessibility to treatment indicate timely action to be undertaken.

Preclinical evaluation of pharmacokinetics and safety of melatonin in propylene glycol for intravenous administration

Melatonin is a highly effective treatment in different animal models of excitotoxicity or ischemia/reperfusion injury. Due to a lack of patentability, commercial sponsors are not interested in funding clinical evaluations of melatonin. Investigators may initiate small-scale clinical evaluation, and intravenous (i.v.) administration is appropriate in acute stroke patients. Institutional Review Boards may require proper preclinical evaluation of the preparation. In this pharmacokinetic and safety study, melatonin in propylene glycol was evaluated in adult male Sprague-Dawley rats. Following a single i.v. injection at 5 or 15 mg/kg, plasma concentrations of melatonin increased to 39 and 199 million pg/mL at 2 min and 128,000 and 772,000 pg/mL at 120 min. Within 60 min of injection, the blood pressure, heart rate and body temperature remained unaffected. Melatonin at 5 mg/kg did not influence the complete blood counts at 60 min, but melatonin at 15 mg/kg had some effects on the differential white cell and platelet counts. Melatonin at 5 or 15 mg/kg slightly elevated some liver enzymes at 60 min of injection, and melatonin at higher dose also elevated plasma creatinine and lactate dehydrogenase levels. At 24 hr after completion of six daily injections of melatonin, there was a 5.5% reduction in body weight. Gross postmortem examination and histological examination of the brain, kidney, liver and spleen did not reveal any evidence of toxicity. In conclusion, melatonin in propylene glycol markedly elevates plasma levels of melatonin with no serious toxicity. This preparation should be further evaluated in human patients.

Melatonin reduces infarction volume in a photothrombotic stroke model in the wild-type but not cyclooxygenase-1-gene knockout mice

Cyclooxygenase (COX)-2 plays a harmful role in cerebral ischemic/reperfusion injury, but the role of COX-1 is uncertain. In the present study, cerebral infarct was induced by photothrombosis. Intraperitoneal injections of melatonin at 15 g/kg or its vehicle were made at 0.5 hr before stroke and 24 and 48 hr after stroke. Cerebral blood flow (CBF) in the penumbra was monitored during stroke using a laser Doppler flowmeter. Sensorimotor behavior was evaluated using the turning in an alley and falling from a pole tests at 1 hr before stroke and 24 and 48 hr after stroke. Infarct volume was determined from the T2-weighted magnetic resonance images at 72 hr after stroke. During the first 15 min of stroke, CBF decreased in the penumbra in both homozygous COX-1-gene knockout and wild-type mice. Melatonin treatment improved the penumbral CBF in the wild-type mice. Mild poststroke impairment in sensorimotor behavior was detected by the turning in an alley test in which the COX-1-gene knockout mice performed better. Melatonin treatment did not affect the poststroke sensorimotor behavior. The relative infarct volume at 72 hr after stroke was 8.1% and 8.4% in the COX-1-gene knockout and wild-type mice, respectively. Melatonin treatment reduced the relative infarct volume to 6.3% in the latter but not in the former (8.2%). Thus, COX-1-gene knockout does not affect the brain's susceptibility to photothrombotic stroke. Melatonin treatment reduces infarct size in the wild-type mice following photothrombotic stroke partly via maintenance of penumbral CBF in which the COX-1-gene may play a role.

Idiopathic inflammatory demyelinating disorders after acute transverse myelitis

Acute transverse myelitis (ATM) is commonly para-infectious. Recurrent ATM occurs in connective tissue diseases (CTD), infective myelitis and idiopathic inflammatory demyelinating disorders (IIDD) including multiple sclerosis (MS) and neuromyelitis optica (NMO). Previous studies might include NMO and idiopathic recurrent transverse myelitis (IRTM) as MS. The aim was to study the outcome of patients after a first attack of idiopathic ATM. Idiopathic ATM patients over a 6-year period were retrospectively studied. Known causes of myelopathy were excluded. Among 32 patients studied, 20 (63%) had single ATM attack upon follow up for 39-93 months, three developed recurrent ATM related to CTD (two systemic lupus erythematosus and one anti-Ro antibody positive) and nine (28.1%) developed recurrent neuroinflammation compatible with IIDD. Among IIDD patients, three had NMO, two restricted variant of NMO, three IRTM and one classical MS. NMO, its variant and IRTM had mean spinal MRI abnormality of 3.7, 2.1 and 3.9 vertebral segments respectively while non-recurrent ATM had 1.6 vertebral segments. Four (80%) of the five patients with NMO or its variant had poor neurological prognosis versus only one (5%) of non-recurrent ATM patients. IRTM patients had advanced mean onset age, 62 years vs. 43 years for non-recurrent ATM patients. In IIDD patients presenting with ATM as first attack of neuroinflammation, NMO and its variant (56%) were most frequent, then IRTM (33%), with classical MS (11%) the rarest. As long-term treatments for NMO are different from MS, early recognition of NMO and its variant is important for prevention of serious neurological deficits.

A possible explanation for the racial difference in distribution of large-arterial cerebrovascular disease: ancestral European settlers evolved genetic resistance to atherosclerosis, but confined to the intracranial arteries

The pattern of cerebral atherosclerosis is not the same among different races. White patients rarely have intracranial large arterial steno-occlusive disease even if their systemic arteries are extensively involved, while non-white patients frequently have their intracranial arteries affected. We postulate that during human population diversification, those who settled in Europe had acquired a stroke-suppressor genotype that increases their resistance against atherogenesis, but with protection confined to the intracranial large arteries. The contemporary affluent lifestyle accelerates the development of atherosclerosis. In the whites, it involves the whole arterial bed except the intracranial vessels. People living in non-Western countries used to have a healthier way of living. They did not develop significant atherosclerotic diseases until recently when a westernised lifestyle was adopted. Unlike the whites, their intracranial arteries will not be spared. Atherosclerosis has become a major cause of premature mortality in the modern world, and an anti-atherogenic mechanism would confer a selection advantage. With further adaptive intensification, this protection may extend to the rest of the arterial bed. As a result, future Homo sapiens will be able to tolerate an affluent lifestyle without much adverse sequel such as premature vascular death. Alternatively, if the mediator of this anti-atherogenic mechanism can be identified and applied therapeutically, we will have an ultimate mean to prevent atherosclerosis.

Myopia as a latent phenotype of a pleiotropic gene positively selected for facilitating neurocognitive development, and the effects of environmental factors in its expression

Myopia has become an almost pandemic problem in many populations. There are compelling evidence to suggest that myopia is a hereditary condition. However, myopia would constitute a definite selection disadvantage during most stages of human evolution, which is incompatible with its moderate to high prevalence in most modern populations. The rapid upsurge of myopia over just a few decades also implies that its inheritance does not follow any of the usual patterns, and environmental factors may have an important role in precipitating its occurrence in those who are genetically predisposed. Previous studies showed that myopes were, on average, more intelligent than non-myopes, and this association had been attributed to a biological link between eye growth and brain development. We propose a pleiotropic genetic model to explain the atypical epidemiologic and inheritance pattern of myopia and its relationship with neurocognitive development. This pleiotropic gene was positively selected for its facilitation of human intelligence. The myopic component is a latent phenotype; myopia will not be expressed unless some novel external factors are encountered (i.e. a "quirk" phenomenon). Therefore, the myopic component was selectively neutral in our ancestral environment. The net gain in Darwinian fitness enables the pleiotropic gene to attain a high frequency in the human population, as reflected by our current prevalence of myopia.

An epidemiological study of motor neuron disease in Hong Kong

Worldwide, the incidence of motor neuron disease (MND) has been increasing steadily over recent decades. We reported a follow-up epidemiology study of MND in this locality. We identified the subjects from the computer database of the government hospital system between 1 January 1997 and 31 January 2002 by searching the ICD code starting from 335.xx. Every retrieved case or their records were reviewed and validated by neurologist(s) of the responsible regional hospitals which the patients attended. One hundred and twenty cases from seven regional hospitals (serving 48.05% of the HKSAR population) were identified, validated and confirmed to be MND or related diseases. Ninety-eight new cases were diagnosed during the study period. Average age of onset was 58.76 years; SD 14.12 (28-89) years. Male to female ratio was 1.72:1. Peak age of onset was 60-64 years without sex difference. The adjusted incidence rate was 0.60/100,000/year. The adjusted point prevalence at the prevalence date (31 January 2001) was 3.04/100,000. Despite the incidence and prevalence of MND among Hong Kong Chinese, it remained low compared to worldwide figures, and our data suggested a significant rise of MND or related disease in the last decade. A territory-wide prospective epidemiological study is indicated.

Cerebral infarcts complicating tuberculous meningitis

Cerebral infarction (CI) is a serious complication of tuberculous meningitis (TBM). It can be asymptomatic or symptomatic, causing stroke. We studied 40 TBM patients. All had initial CT brain scan, CT/MRI brain scan 3 months later and urgent CT brain scan for deterioration. CI was classified into lacunar infarction (LI) or large artery infarction (LAI). Twelve (30%) had CI, in 9 (23%) it was symptomatic and in 3 (8%) silent. Seven (58%) had LAI +/- LI. Eight (67%) had multiple CI. Two died from brainstem CI and 6 were dependent at 1 year. Patients with LAI might develop posterior circulation CI more frequently than those with LI only. CI is a common complication of TBM locally, with LAI and multiple CI being common. Two thirds of TBM patients complicated by CI had poor prognosis despite adjunctive dexamethasone treatment.

Cerebrospinal fluid to serum glucose ratio in non-hypoglycorrhachic neurological conditions

OBJECTIVE

To explore the relevance of cerebrospinal fluid to serum glucose ratio in non-hypoglycorrhachic conditions.

DESIGN

Retrospective observational study.

SETTING

Neurology ward, university teaching hospital, Hong Kong.

PATIENTS

Adult patients with conditions unrelated to hypoglycorrhachia who underwent lumbar puncture.

MAIN OUTCOME MEASURES

Cerebrospinal fluid and simultaneous serum glucose concentrations, and their ratio to each other.

RESULTS

Between September 1998 and August 2003, 170 cerebrospinal fluid and serum glucose samples were collected from 138 patients. Mean cerebrospinal fluid to serum glucose ratio was 0.61 (standard deviation, 0.142; range, 0.21-1.00). With the exception of cerebrospinal fluid protein level, laboratory parameters were similar among different diseases. The glucose ratio was lower than 0.6 in 43% and lower than 0.5 in 19% of samples. Cases with a low glucose ratio appeared to have higher serum glucose concentrations (significant among groups with different glucose ratios, P<0.001). The mean glucose ratio (0.65) was also significantly higher in patients with serum glucose concentration of lower than 7.8 mmol/L compared with those with serum glucose concentration between 7.8 and 11.1 mmol/L (mean, 0.46), or higher than 11.1 mmol/L (mean, 0.46) [P<0.001]. There was a strong negative correlation between the glucose ratio and serum glucose concentration (r= -0.704, P<0.001).

CONCLUSION

A lowered cerebrospinal fluid to serum glucose ratio is often seen in the absence of an appropriate disorder, especially when simultaneous serum glucose concentration is elevated. This may be explained by the saturation kinetics of glucose transportation in hyperglycaemia, and the time lag for cerebrospinal fluid and glucose to equilibrate when the blood level fluctuates.

Neuropeptide Y-Y1 receptor agonist worsens while antagonist improves survival of cultured Y1-expressing neuronal cells following oxygen and glucose deprivation

In this in vitro study, we investigated the influence of neuropeptide Y (NPY) Y1 receptor activation or inhibition on the viability of cultured neuronal or glial cells following oxygen glucose deprivation (OGD). Viability of cultured cells was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. When compared to the vehicle-treated control group, treatment with NPY or [Leu31,Pro34]-NPY (Y1 agonist) reduced viability of cultured SK-N-MC (Y1-expressing) human neuronal cells at 24 h after 1 h of OGD, while BIBP3226 (Y1 antagonist) improved viability. Except at the highest concentration of NPY used in the study, treatment with NPY or NPY3-36 (Y2 agonist) did not influence viability of cultured SH-SY5Y (Y2-expressing) human neuronal cells at 24 h after 1 h of OGD. In addition, treatment with NPY, [Leu31,Pro34]-NPY, NPY3-36, or BIBP3226 did not affect viability of cultured primary astrocytes at 24 h after 4 h of OGD. The present results agree with those of a recent in vivo study. Activation of NPY-Y1 receptors may mediate ischemic pathophysiological processes, and inhibiting the Y1 receptors may be protective. The combination of OGD and cultured neuronal cells may be useful in future studies on the neuroprotective and harmful mechanisms of NPY-Y1 receptor inhibition and activation during ischemia, respectively.

Wilson’s disease with depression and parkinsonism

Wilson's disease (WD) is an autosomal recessive disorder with reduced biliary excretion of copper plus impaired formation of ceruloplasmin, leading to copper accumulation in the liver, brain, kidney, and cornea. Clinical manifestations include liver damage, psychiatric symptoms, and neurological features. We report a 35-year-old woman with a history of deranged liver functions who had severe depression several years later and eventually presented with parkinsonian features. The underlying diagnosis is WD and family screening revealed WD in 2 other siblings. She could not tolerate penicillamine because of fever and leucopenia. While taking trientine hydrochloride and zinc sulphate, her parkinsonism improved and her depression remained in remission. WD should be considered in patients with unexplained liver function derangement or psychiatric symptoms. Early diagnosis and initiation of specific treatment are crucial in minimising any further cerebral and hepatic damage as well as securing possible improvement in organ functions.

Neuropeptide Y and its receptor analogs differentially modulate the immunoreactivity for neuronal or endothelial nitric oxide synthase in the rat brain following focal ischemia with reperfusion

An intracerebroventricular (i.c.v.) injection of neuropeptide Y (NPY) or [Leu31, Pro34]-NPY (non-Y2 receptor agonist) given during middle cerebral artery occlusion (MCAO) increases the infarct volume and nitric oxide (NO) overproduction in the rat brain. An i.c.v. injection of NPY3-36 (non-Y1 receptor agonist) has no effects, while BIBP3226 (selective Y1 receptor antagonist) reduces the infarct volume and NO overproduction. This study examined the effects of NPY or its receptor analog on the immunoreactivity (ir) for three isoforms of NO synthase (NOS) following 1 h of MCAO and 3 h of reperfusion. Focal ischemia/reperfusion led to increased ir for neuronal NOS (nNOS) within the ipsilateral caudate putamen and insular cortex. NPY or [Leu31, Pro34]-NPY enhanced but BIBP3226 suppressed such increase in the nNOS-ir. Focal ischemia/reperfusion also led to an ipsilateral increase in extent and/or intensity of the ir for endothelial NOS (eNOS) in the caudate putamen and/or parietal cortex. NPY or [Leu31, Pro34]-NPY suppressed but BIBP3226 enhanced such change in the eNOS-ir. NPY3-36 did not consistently influence the nNOS-ir or eNOS-ir following MCAO. Specific ir for inducible NOS was undetectable. These opposing effects of NPY-Y1 receptor activation or inhibition on nNOS and eNOS may lead to harmful or beneficial consequences following ischemia/reperfusion.

Cerebral venous thrombosis in a gentleman presenting with fever, convulsion and frontotemporal haemorrhages

Cerebral venous thrombosis (CVT) is an uncommon but serious type of stroke. Thrombosis may involve the cortical or deep veins or the venous sinuses. The presenting clinical features are non-specific. We report a 48-year-old man with CVT who presented with fever, bitemporal throbbing headache, and generalised convulsion. Computed tomography (CT) of the brain revealed acute haemorrhages over right anterior frontal and posterior temporal regions with surrounding oedema and right anterior temporal subcortical oedema. The initial diagnosis was herpes simplex encephalitis. Absence of venous flow over the right transverse and sigmoid sinuses during the venous phase of digital subtraction angiography (DSA) revealed CVT. He was anti-coagulated for 6 months. An underlying cause of CVT was not detected. A high index of suspicion is required when risk factors of CVT are present. CT brain may be normal or showing non-specific findings. Magnetic resonance imaging plus venography, CT venography, or DSA is diagnostic.

Idiopathic severe recurrent transverse myelitis: a restricted variant of neuromyelitis optica

Recurrent idiopathic transverse myelitis occur in multiple sclerosis (MS) and neuromyelitis optica (NMO). In NMO, acute optic neuritis and myelitis occur, either monophasic or relapsing, without clinical manifestations of involvement of other parts of the central nervous system (CNS). Recent evidence suggests that NMO is different from multiple sclerosis. The authors reported two patients having severe recurrent transverse myelitis sparing the optic nerves and cerebral hemispheres. Both patients had longitudinally extensive myelitis in some attacks with poor neurological outcome despite aggressive immunomodulatory therapy. One patient had prominent clinical features of brainstem injury with radiological and histological confirmation of brainstem involvement, and the other patient had trigeminal neuralgia suggestive of possible brainstem dysfunction. Histologically, prominent necrosis and neutrophilic infiltration of spinal cord tissue without eosinophils or hyalinized vessels were observed, and oligoclonal bands were absent in their cerebrospinal fluid. It is likely to be a distinct idiopathic inflammatory demyelinating disorder restricted to the spinal cord and brainstem different from MS, but within the spectrum of NMO with probably an autoimmune basis.

Pretreatment with melatonin exerts anti-inflammatory effects against ischemia/reperfusion injury in a rat middle cerebral artery occlusion stroke model

Inflammatory response following cerebral ischemia/reperfusion plays a key pathogenic role in ischemic cerebral damage. Nitric oxide (NO), cyclooxygenase-2 (COX-2) and myeloperoxidase (MPO) are important inflammatory mediators. Neuronal NO synthase (nNOS) is a major initial source of excessive NO during ischemia/reperfusion. Induction of COX-2 and infiltration of polymorphonuclear cells expressing MPO are critical factors in delayed inflammatory damage. Previously, we demonstrated that administration of melatonin before ischemia significantly reduced the infarct volume in a rat middle cerebral artery occlusion (MCAO) stroke model. In this study, we examined the effect of pretreatment with melatonin at 5 mg/kg on the immunoreactivity (ir) for nNOS, COX-2, MPO, and glial fibrillary acidic protein (GFAP) at 24, 48, and 72 hr after right-sided endovascular MCAO for 1 hr in adult male Sprague-Dawley rats. Melatonin did not affect the hemodynamic parameters. When compared with rats with sham MCAO, ischemia/reperfusion led to an ipsilateral increase in cells with positive ir for nNOS (similar at all times) and in ir-GFAP (similar at all times). Ischemia/reperfusion led to appearance of cells with positive ir for COX-2 (greatest at 24 hr with a tendency to increase again at 72 hr) or MPO (greatest at 24 hr). A single dose of melatonin significantly lessened the ipsilateral increase in cells with positive ir for nNOS, COX-2 or MPO, but did not influence the ipsilateral change in ir-GFAP. Our results suggest that melatonin treatment mediates neuroprotection against ischemia/reperfusion injury partly via inhibition of the consequential inflammatory response.

Consensus statement on ischaemic stroke care in Hong Kong

OBJECTIVE

To issue guidelines for the care of acute stroke in Hong Kong, with the target audience of all health care professionals who are involved in acute stroke care.

PARTICIPANTS

The Hong Kong Neurological Society and the Hong Kong Stroke Society.

EVIDENCE

The panel applied the 'rule of evidence' used by the United States Agency for Health Care Policy and Research. When there is insufficient evidence, the recommendation was based on customary practice and was circulated among the members and fellows of the two societies before coming to a consensus.

CONSENSUS PROCESS

Group meetings were held in 2002 to review the literature about acute care for patients with ischaemic stroke and to issue a consensus statement with reference to the local health care system. Participants of the meetings were appointed by the councils of The Hong Kong Neurological Society and the Hong Kong Stroke Society. The draft statement was circulated among the members and fellows of the two societies for comments before it was finalized.

CONCLUSIONS

Ischaemic stroke is a heavy health care burden to Hong Kong. The current consensus statement provides a framework to establish a multidisciplinary approach towards its acute management.

Clinical relevance of hydrocephalus as a presenting feature of tuberculous meningitis

BACKGROUND

Hydrocephalus is a common complication of tuberculous meningitis (TBM).

AIM

To study the incidence, associated clinical features, and impact on outcome of hydrocephalus at presentation in TBM.

DESIGN

Observational study.

SETTING

Regional hospital serving 500,000 people.

METHODS

Adult patients with TBM were studied over 57 months. Those with hydrocephalus on initial CT scan were assessed by neurosurgeons. Clinical, neuroradiological, and biochemical features of patients with hydrocephalus upon presentation were compared to those without initial hydrocephalus.

RESULTS

Of 31 TBM patients during the study period, nine (29.0%) had hydrocephalus at presentation, and eight of them (25.8% of all) underwent urgent neurosurgical intervention. Of the 22 patients without initial hydrocephalus, hydrocephalus developed after commencement of chemotherapy in one patient only. Hydrocephalus at presentation was associated with a longer duration of presenting symptoms (p = 0.01), ataxia (p = 0.001), later stages of TBM (p = 0.045), a longer delay before commencement of anti-tuberculous chemotherapy (p = 0.001), stroke (p = 0.012), and a poor outcome at 1 year (p = 0.001).

DISCUSSION

Hydrocephalus upon presentation is common in our TBM patients. This may be a poor prognostic marker associated with severe TBM and a higher risk of stroke.

Use of the original, modified, or new intracerebral hemorrhage score to predict mortality and morbidity after intracerebral hemorrhage

BACKGROUND AND PURPOSE

A simple clinical scale of intracerebral hemorrhage (ICH), comprising the Glasgow Coma Scale score, age, infratentorial origin, ICH volume, and intraventricular hemorrhage, was recently shown to predict 30-day mortality. We studied how well the original ICH Score would predict morbidity and mortality and determined whether modification would improve the predictions.

METHODS

Patients admitted to a regional hospital with acute ICH in 1999 were reviewed. Independent predictors of mortality or good outcome (modified Rankin score <or=2) at 30 days were identified by logistic regression to devise a new ICH Score for comparison with the original Score. A modified Score was created by substituting National Institutes of Health Stroke Scale (NIHSS) for the Glasgow Coma Scale.

RESULTS

The mortality rate was 22%, and 35% had good outcome. Independent factors for mortality were high NIHSS score, intraventricular hemorrhage, subarachnoid extension, and narrow pulse pressure. Independent factors for good outcome were low NIHSS score and low admission temperature. For all ICH Scores, no patient had a maximum score of 6. Cutoff values of >or=3 and <3 provided the best Youden's index of diagnostic test in all ICH Scores for mortality and good outcome, respectively. The original and modified ICH Scores predict mortality equally well. The new and modified ICH Scores are slightly better for prediction of good outcome.

CONCLUSIONS

All 3 ICH Scores are simple clinical grading scales. As reliable predictors of good outcome and/or mortality, they are useful in clinical research studies and standardization of clinical protocols.

Intracerebroventricular injection of a neuropeptide Y-Y1 receptor agonist increases while BIBP3226, a Y1 antagonist, reduces the infarct volume following transient middle cerebral artery occlusion in rats

Recent studies using middle cerebral artery occlusion in the rat have suggested a role of neuropeptide Y in ischemic pathophysiology. In this study, we investigated the effects of an i.c.v. injection of a neuropeptide Y-Y2 receptor agonist, neuropeptide Y 3-36, a Y1 receptor agonist, [Leu(31),Pro(34)]-neuropeptide Y, or a Y1 receptor antagonist, BIBP3226, on infarct volume and hemodynamic parameters following middle cerebral artery occlusion. Adult male Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion for 2 h. A single i.c.v. injection of neuropeptide Y 3-36 (15 microg/kg), [Leu(31),Pro(34)]-neuropeptide Y (30 microg/kg), or BIBP3226 (5, 15, or 45 microg/kg) was given at 30 min of ischemia. Blood pressure, heart rate, and regional cerebral perfusion were monitored during ischemia and reperfusion. The rats were decapitated after 70 h of reperfusion, and their brains were cut into 2-mm-thick coronal slices before reaction with a 2% solution of 2,3,5-triphenyltetrazolium chloride to reveal the infarct. When compared with an infarct volume of 17.4+/-4.4% of the ipsilateral hemisphere following injection of neuropeptide Y 3-36, administration of the Y1 receptor analogs significantly modified the infarct volume (ordinary one-way analysis of variance (ANOVA), P<0.0001). [Leu(31),Pro(34)]-neuropeptide Y increased the infarct volume to 32.0+/-4.1% (Student-Newman-Keuls post-test, P<0.01), whereas BIBP3226 at 15 microg/kg decreased the infarct volume to 6.5+/-1.0% (post-test P<0.05). Although there was no major difference in the hemodynamic parameters among the groups, injection of [Leu(31),Pro(34)]-neuropeptide Y tended to further reduce cerebral perfusion during ischemia, while injection of BIBP3226 at 15 microg/kg appeared to have the opposite effect. In addition to glutamate, calcium ion and nitric oxide, activation of the neuropeptide Y-Y1 receptors may mediate cerebral damage during focal ischemia. Conversely, inhibiting the Y1 receptors may protect the brain against ischemic injury. Further studies are warranted to confirm the neuroprotective potential of neuropeptide Y-Y1 receptor inhibition.

Visualization of ischaemic penumbra using a computed tomography perfusion method

A computed tomography (CT) perfusion imaging and a diffusion/perfusion magnetic resonance imaging (MRI) were performed in a 51-year-old man at 15 and 15.5 h of onset of left middle cerebral artery infarction, respectively. The established infarct, as revealed by the diffusion-weighted MRI, had low values of cerebral blood flow (CBF) and cerebral blood volume (CBV) on the CT perfusion study. The ischaemic penumbra, as reflected by the perfusion-diffusion mismatch on MRI, had reduced CBF, prolonged mean transit time (MTT) and compensated CBV. Spontaneous bleeding occurred in the medial part of the left lentiform nucleus, immediately following decompressive craniectomy. CT measurements of CBF, CBV and MTT may visualize the ischaemic penumbra and explain the site of bleeding after surgical decompression.

Tuberculous meningitis with tuberculomata presenting as postpartum pyrexia of unknown origin

A35-year-old Chinese woman had primary infertility as a result of bilateral fallopian tube blockage. She had had uterine fibroids resected 3 years previously. Her precious pregnancy via in-vitro fertilization was complicated by premature rupture of amniotic membrane at 18 weeks' gestation. Two doses of betamethasone 12 mg were given at 29 weeks' gestation, and fetal bradycardia was noted on the next day. A baby girl was delivered by emergency caesarean section. The patient had a high swinging fever following the delivery. Extensive investigations for postpartum pyrexia were normal or negative. She was given courses of broad-spectrum antibiotics for 4 weeks before she developed mental dullness and right partial ptosis. On the next day, she became disorientated with left hemiplegia. Examination also revealed left-sided neglect, dysphasia, conjugate gaze deviation to the right, and left homonymous hemianopia. Computed tomography (CT) of the brain revealed a left temporal hypodense area (Figure 1a). Lumbar puncture revealed the following CSF findings: opening pressure of 34 cmH2O, protein level of 3.8 g/litre, glucose level of 2.1 mM (serum 6.4 mM), cell count of 30 × 106/litre (56% lymphocytes, 40% neutrophils, 4% monocytes), and red cell count of 11 × 106/litre. Other CSF tests were negative.

Melatonin protects SHSY5Y neuronal cells but not cultured astrocytes from ischemia due to oxygen and glucose deprivation

As a potent free radical scavenger and antioxidant, melatonin protects brain tissue against ischemia-reperfusion injury, partly via suppression of ischemia-induced production of nitric oxide, when given before ischemia-reperfusion or within 2 hr of onset of ischemia. In this study, we examined the neuroprotective effect of melatonin in an in vitro model of ischemia. Primary cultured astrocytes were subjected to 4 or 8 hr of oxygen-glucose deprivation (OGD), and cultured SHSY5Y human neuronal cells were exposed to 1 hr of OGD. Melatonin was added to the medium at the commencement of OGD to achieve different final concentrations, and cell death was quantified using the measurement of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) at 24 hr after reversion of OGD. Treatment with melatonin did not affect the astrocytic cell death following 4 or 8 hr of OGD. The relative MTT values of the neuronal cells were (as mean +/- S.E.M.) 59.1 +/- 2.4% in the vehicle-treated OGD group and 80.1 +/- 2.7%, 82.5 +/- 2.9%, 74.1 +/- 2.3%, 64.2 +/- 2.3%, 62.7 +/- 2.8%, and 61.0 +/- 3.9% in the OGD groups treated with melatonin at 10(-3), 10(-4), 10(-5), 10(-6), 10(-7), and 10(-8) m, respectively. Reduction in cell death was significant following treatment with melatonin at 10(-3), 10(-4), or 10(-5) m. Reverse transcription-polymerase chain reaction showed that human mt1 and MT2 membrane receptors were not expressed in the cultured neuronal cells. Our results show that melatonin co-treatment protects cultured neuronal cells but not astrocytes against OGD-induced cell death in a dose-dependent manner and that the neuroprotection is independent of its known membrane receptors.

The utility of melatonin in reducing cerebral damage resulting from ischemia and reperfusion

The brain is highly susceptible to focal or global ischemia. Unless ischemia is promptly reversed, reperfusion produces further cerebral damage. Acute thrombolysis or defibrinogenation is effective only in selective patients with ischemic stroke and carries a significant risk of bleeding complications. Whereas numerous neuroprotectants were shown to be effective in experimental studies, none of them have been shown to work in clinical trials. The major pathogenetic mechanisms of ischemia/reperfusion injury include excitotoxicity, disturbed calcium ion homeostasis, overproduction of nitric oxide and other free radicals, inflammation, and apoptosis. Nitric oxide and other free radicals, the key mediators of excitotoxicity and disturbed calcium ion homeostasis, cause direct injury and also indirectly damage via inflammation and apoptosis. Melatonin is a potent free radical scavenger and an indirect antioxidant. This mini review summarizes the in vivo and in vitro evidence that melatonin protects against ischemia/reperfusion injury. There is convincing evidence from the literature that melatonin treatment is highly effective in different in vivo and in vitro models of excitotoxicity or ischemia/reperfusion in multiple animal species. Melatonin is safe and non-toxic in humans, and its administration via the oral route or intravenous injection is convenient. While more experimental studies should be conducted to further explore the neuroprotective mechanisms and to document any synergistic or additive protection from combining melatonin with thrombolysis, defibrinogenation or other neuroprotectants, interested clinical scientists should consider planning phase II and III studies to confirm the benefit of melatonin as an acute stroke treatment or a preventive measure for stroke patients.

Administration of melatonin after onset of ischemia reduces the volume of cerebral infarction in a rat middle cerebral artery occlusion stroke model

BACKGROUND AND PURPOSE

In both permanent and transient 3-hour middle cerebral artery occlusion rat stroke models, a single intraperitoneal injection of melatonin at 5 or 15 mg/kg given before ischemia was shown to reduce infarct volume at 72 hours. The present study was conducted to examine the treatment time window when melatonin was commenced after onset of ischemia.

METHODS

Adult male Sprague-Dawley rats were anesthetized to undergo right-sided middle cerebral artery occlusion for 3 hours. A single intraperitoneal injection of vehicle or melatonin at 5 mg/kg was given at 0, 1, or 3 hours after onset of ischemia. Other groups received multiple injections of vehicle or melatonin at 5 mg/kg with the first injection given at 1, 2, or 3 hours after onset of ischemia and the second and third injections at 24 and 48 hours, respectively. Multiple injections of melatonin at 15 mg/kg with the first injection given at 3 hours were also made. The infarct volume was determined at 72 hours.

RESULTS

A single dose of melatonin at 5 mg/kg given at 0 or 1 but not 3 hours after onset of ischemia reduced the infarct volume. Multiple doses of melatonin at 5 mg/kg also reduced the infarct volume when the first dose was given at 1 or 2 but not 3 hours after onset. Significant hemodynamic effects were not observed.

CONCLUSIONS

Our results indicate that melatonin at 5 mg/kg given as a single injection or multiple injections protects against focal cerebral ischemia when commenced within 2 hours of onset.

Melatonin reduces nitric oxide level during ischemia but not blood-brain barrier breakdown during reperfusion in a rat middle cerebral artery occlusion stroke model

Melatonin is a potent antioxidant and free radical scavenger. Previously, we showed that a single injection of melatonin before ischemia significantly reduced the infarct volume in both permanent and 3-hr middle cerebral artery occlusion (MCAO) rat stroke models. Nitric oxide (NO) and other free radicals play an important role in the pathogenesis of cerebral ischemia, and they have been postulated to mediate the breakdown of the blood-brain barrier (BBB) during ischemia. In this study, we evaluated the influence of melatonin, given at 30 min before MCAO, on brain NO concentration and BBB breakdown. Brain NO concentration was measured at 15 min of MCAO using electron paramagnetic resonance spectroscopy. BBB breakdown at 3 hr of reperfusion following 3 hr of MCAO was assessed using Evans blue extravasation. The relative brain NO concentration was increased to 141.69 +/- 9.71% (mean +/- S.E.M.; n = 9) at 15 min of MCAO. Treatment with melatonin at 1.5, 5, or 50 mg/kg significantly reduced the brain NO concentration to 104.20 +/- 11.20% (n = 8), 55.67 +/- 5.58% (n = 11), and 104.86 +/- 12.56% (n = 9), respectively. Melatonin at 5 mg/kg did not affect Evans blue extravasation. Our results suggest that a single injection of melatonin protects against focal cerebral ischemia partly via inhibition of ischemia-induced NO production and that this regimen does not prevent BBB breakdown following ischemia-reperfusion.

Pretreatment with melatonin reduces volume of cerebral infarction in a rat middle cerebral artery occlusion stroke model

Melatonin is a potent scavenger of free radicals and an indirect antioxidant. Recent studies have shown that melatonin possesses beneficial effects in experimental models of brain trauma and global cerebral ischemia. The effects of pretreatment with melatonin on volume of cerebral infarction were investigated in the present study. Adult male Sprague-Dawley rats were anesthetized with sodium pentobarbital to undergo right-sided endovascular middle cerebral artery occlusion (MCAO) for 3 hr. A single dose of melatonin (1.5, 5, 15, or 50 mg/kg in 1 mL normal saline) or its vehicle was given via an intraperitoneal injection at 0.5 hr before MCAO. Relative infarction volumes on day 3 after MCAO were significantly reduced in the groups treated with melatonin at 5 (mean +/- S.E.M., 15.7 +/- 2.5%) or 15 (21.4 +/- 3.1 %) mg/kg but not at 1.5 (30.6 +/- 3.5%) or 50 (26.7 +/- 2.8%) mg/ kg when compared with the vehicle group (33.9 +/- 3.5%). There was no significant difference in the arterial blood pressure (BP), heart rate (HR) and relative cerebral blood flow among the experimental groups. These results indicate that pretreatment with melatonin at a dose between 5 and 15 mg/kg protects against focal cerebral ischemia.