Long term ketamine and ketamine plus alcohol toxicity - what can we learn from animal models?

This review addressed the adverse effects of the frequently-used recreational drug, ketamine through using mice and monkey models. Our laboratory has documented initially that ketamine can induce the formation of hyperphosphorlated tau (hypertau), which is a hallmark of Alzheimer's disease (AD), in the cerebral cortex of both mice and monkeys as well as apoptosis in neurons in these species. Besides the cerebral cortex, other centers in the central nervous system (CNS) and peripheral nervous system (PNS) are also influenced by ketamine. Cerebellum was found to be down-regulated in both mice and humans after long-term of ketamine administration and it was caused by the apoptosis of Purkinje cells. Deleterious effects in other organs reported in long-term ketamine users include of kidney dysfunction leading to proteinuria, fibrosis of the urinary bladder and reduction in size of the urinary bladder leading to frequent urination, increase of liver fibrosis and cardiac problems such as premature ventricular beats. Moreover, ketamine is usually co-administrated with other chemicals such as caffeine or alcohol. It has been reported increased harmful effects when ketamine was used in combination with the above substances. Mechanisms of damages of ketamine might be due to 1) up-regulation of NMDA receptors leading to overestimation of glutamatergic system or 2) the metabolite of ketamine which was a hydroquinone exerted toxicity.

Effects of built environment on walking among Hong Kong older adults

1. Reliable and valid interviewer-administered questionnaires were developed to investigate associations of perceived neighbourhood attributes of Hong Kong older adults with their walking for transportation and recreation. 2. Access to and availability of different types of services and destinations, provision of facilities for resting/sitting in the neighbourhood, and easy access to/from residential buildings may help maintain an active lifestyle by facilitating walking for transport in the neighbourhood. 3. Access to services, indoor places for walking, environmental aesthetics, low traffic, and absence of physical barriers may promote recreational walking..

Development of a wearable system integrated with novel biomedical sensors for ubiquitous healthcare

The world's ageing population has led to an urgent need for long-term and patient-centered healthcare solutions. Hence, there is a growing need for wearable systems for physiologic monitoring. While various biosignals are monitored with traditional approaches, it is worthwhile to investigate alternative sensing techniques in order to improve accessibility and understanding of patients' conditions. This paper presents our laboratory's development of such a wearable system, which makes use of unconventional techniques for physiologic monitoring. With its integrated textile electrocardiogram (ECG) electrodes, intelligent finger-ring photoplethysmogram (PPG) sensor, miniaturized optical fiber-based temperature sensor, eye dynamics monitor, global positioning system (GPS) module, and wireless capability, it demonstrates a feasible solution for ubiquitous healthcare.

DL-3-n-Butylphthalide, an anti-oxidant agent, prevents neurological deficits and cerebral injury following stroke per functional analysis, magnetic resonance imaging and histological assessment

DL-3-n-Butylphthalide (NBP) is a synthetic compound based on L-3-n-Butylphthalide which was isolated from seeds of Apium graveolens. The present study aims at evaluating the outcome of NBP given prior to and after the onset of ischemic stroke in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Stroke was induced by the middle cerebral artery occlusion (MCAO) in SHR and WKY. For pre-treatment, NBP was administered to SHR and WKY daily for two months prior to MCAO. For post-treatment, NBP was given daily for seven consecutive days after MCAO. Seven days post-surgery, rats were tested for the presence of neurological deficits. Magnetic resonance imaging (MRI) and 2,3,5-triphenyltetrazolium chloride (TTC) staining were employed to calculate the infarct volume. The cerebral cortex and corpus striatum in the ischemic penumbra area were examined microscopically for pathological changes. In SHR, NBP pre- and post-treatment significantly lowered neurological deficit scores, reduced infarct volume, and minimized pathological changes in the penumbra area when compared to oil-vehicle treated controls. In WKY, these beneficial effects were observed only in the post-treatment group. The beneficial effects of NBP post-treatment were greater in WKY than in SHR. Results indicated that NBP could exert both preventive and therapeutic effects on ischemic stroke in SHR, but only exerted therapeutic effect in WKY.

Serotonin and its receptors in the human CNS with new findings - a mini review

Serotonin (5-hydroxytryptamine, 5-HT) is well known to be closely associated with emotional disorders, such as depression and schizophrenia. The seven main members of 5-HT receptor family including the different subtypes are involved in the functional pathways in the brain and their balance in activity helps to maintain the normal mental stability. As any detrimental changes in the 5-HT system is believed to alter emotion in human, different drugs including serotonin reuptake inhibitors (SSRIs) are nowadays commonly used as anti- depressives. In this review, 5-HT(1A) and 5-HT(2A) receptors and serotonergic positive cells in the human were highlighted in particular. It is hoped that this review will give a map of these major 5-HT receptors and serotonergic neurons in the human CNS to facilitate further deciphering of their functions.

Association between HbA1c and cardiovascular disease mortality in older Hong Kong Chinese with diabetes

OBJECTIVE

To examine the association between baseline HbA(1c) level and mortality attributable to all-cause, cardiovascular disease, coronary heart disease and stroke.

METHODS

A total of 2137 Chinese aged 65 years or above attending the Elderly Health Service, Department of Health, Hong Kong, with diagnosed diabetes had HbA(1c) measured during 1998 to 2000 and were followed up to 2009. Information on socio-economic position, lifestyle factors and disease history was collected. Hazard ratios and 95% confidence intervals with adjustment for potential confounders were calculated using Cox's proportional hazards models.

RESULTS

After an average of 7.9 years of follow-up, 540 participants had died. After adjusting for potential confounders, higher HbA(1c) (≥ 69 mmol/mol, 8.5%) increased the risk of cardiovascular disease (hazard ratio 2.11;95% CI 1.37-3.25) and stroke mortality (hazard ratio 2.43; 95% CI 1.06-5.55) compared with HbA(1c) of 58-68 mmol/mol (7.5-8.4%), and increased the risk of all-cause (hazard ratio 1.41; 95% CI 1.06-1.86) and coronary heart disease mortality (hazard ratio 2.44; 95% CI 1.11-5.37) compared with HbA(1c) of 48 mmol/mol (6.5%) or less. Analysis of HbA(1c) as a continuous variable showed that every XX mmol/mol (1%) increase in HbA(1c) decreased stroke mortality risk by 51% in those with HbA(1c) level less than 48 mmol/mol (6.5%) and increased stroke mortality risk by 30% in those with an HbA(1c) level of 48 mmol/mol (6.5%) or higher, suggesting a U-shaped association between HbA(1c) and stroke mortality.

CONCLUSION

High HbA(1c) predicted excess risk of all-cause, cardiovascular disease, coronary heart disease and stroke mortality. The question of whether low HbA(1c) increases mortality in older patients with diabetes needs further investigation.

Long-term ketamine and ketamine plus alcohol treatments produced damages in liver and kidney

Ketamine is one of the common recreational drugs used in rave parties and it is frequently taken with alcohol. In spite of this, the potential toxicity of ketamine in liver and kidney has not been fully documented. In this study, ICR mice were treated for periods of 6, 16 and 28 weeks with 30 mg/kg ketamine injected daily intraperitoneally, and together with alcohol (0.5 ml of 10% alcohol for each mouse) during the last 4 weeks of the treatment periods. Our experimental results showed significant damage in liver, including fatty degeneration of liver cells, fibrosis and increase in liver glutamic oxaloacetic transaminase, proliferative cell nuclear antigen and lactate dehydrogenase after 16 weeks of treatment with ketamine. Hydropic degenerations of the kidney tubules were observed as early as 6 weeks of treatment. Long-term ketamine administration (28 weeks) led to atresia of glomeruli in the kidney. Proteinuria was confirmed in the 67% of the ketamine-treated animals after 28 weeks of treatment. It was apparent that ketamine when taken chronically (16 weeks of treatment and thereafter) affected both liver and kidney definitively. The damages in both liver and kidney of these mice were more severe when the animals were treated with both ketamine and alcohol.

Influenza vaccination and hospitalisation in Elderly Health Centres

1. A cohort of Elderly Health Centres was examined to determine whether influenza vaccination decreased hospitalisation and mortality. 2. In the influenza season, influenza vaccination reduced all-cause mortality by half and cardiorespiratory hospitalisation by a quarter. The extent to which influenza vaccination protects older people from serious morbidity and mortality needs to be confirmed in appropriately designed studies, so that scarce health care resources can be used effectively

Older people with diabetes have higher risk of depression, cognitive and functional impairments: implications for diabetes services

OBJECTIVES

To examine the relationship between diabetes and impairments in functional and cognitive status as well as depression in older people.

DESIGN

Cross-sectional study.

SETTING

Elderly Health Centres (EHC) in Hong Kong.

PARTICIPANTS

66,813 older people receiving baseline assessment at EHC in 1998 to 2001.

MEASUREMENTS

Diabetes status was defined by self-report and blood glucose tests. Functional status was assessed by 5 items of instrumental activities of daily living (IADL) and 7 items of activities of daily living (ADL). Cognitive status was screened by the Abbreviated Mental Test-Hong Kong version (AMT). Depressive symptoms were screened by the Geriatric Depression Scale-Chinese version (GDS).

RESULTS

Among the subjects, 10.4% reported having regular treatment for diabetes, 3.4% had diabetes but were not receiving regular treatment, and 86.2% did not have diabetes. After controlling for age, sex and education level, those having regular treatment for diabetes were 1.7 times more likely (OR=1.65, 95% CI: 1.51-1.80) to have functional impairment, 1.3 times more likely (OR=1.28, 95% CI: 1.11-1.48) to have cognitive impairment and 1.3 times more likely (OR=1.35, 95% CI: 1.25-1.46) to have depression, than older people without diabetes.

CONCLUSION

Older people with diabetes may be less capable of managing the disease than the younger ones as a result of increased risk of both physical and cognitive impairment. This study provided further evidence for the need of an international consensus statement regarding care of diabetes in older people.

Cardiotoxicity induced in mice by long term ketamine and ketamine plus alcohol treatment

Increased use of ketamine as a recreational drug in rave party has raised lots of social concerns. Although its toxicity on the central nervous system (CNS) and urinary system had been reported, its potential adverse effects on the heart is still not addressed. Using our long term ketamine addiction model in which, 1-month-old ICR mice were given ketamine intraperitoneally (i.p. 30 mg/kg) for different study periods (6 weeks, 16 weeks and 28 weeks). The electrocardiogram (ECG) and the level of troponin as well as the presence of lactate dehydrogenase were used together to determine the cardiac function of mice. ST elevations were observed in 30% of mice from 6 weeks onwards. Concomitant increase in troponin in serum and presence of lactate dehydrogenase positive cardiac cells were taken together to indicate cardiac damages. The potential interactive effects of alcohol (ethanol) and ketamine were also addressed and 0.5 ml of 10% ethanol was administrated additionally to the mice daily and orally for the last 4 weeks in the 28-week long-term ketamine treated animals. The cardiac functions of these mice deteriorated more severely as indicated by further rise in troponin levels. In addition, high number of lactate dehydrogenase positive cardiac cells and abnormal ECGs in both ketamine and ketamine plus alcohol treated models also gave coherent conclusions.

Downregulation in the human and mice cerebella after ketamine versus ketamine plus ethanol treatment

To study the deleterious effects of ketamine and the potential interaction effects between ethanol and ketamine on the cerebellum, functional magnetic resonance imaging (fMRI) tests were performed on the habitual ketamine users (n = 3) when they flexed and extended their upper limbs. Another fMRI test was performed on the same participants in which they consumed alcohol (12%, 200 mL) 1 h before the test. Downregulation on the activity of cerebellum was observed and the level of activation in the cerebellum decreased dramatically in habitual ketamine users with alcohol consumption before the test. Further studies were performed by using male ICR mice receiving treatment of ketamine only [30 mg kg(-1) intraperitoneally (i.p.)] or ethanol only everyday (0.5 mL 12% orally) and those with coadministration of the above dosages of ketamine and ethanol for 3 months. Fewer Purkinje cells were observed in the cerebellar sections of ketamine treated mice under silver staining. For TUNEL test, a significant increase in the apoptotic cells were observed in the cerebella of the ketamine treated mice (P = 0.016) and of those with co-administration of ketamine and ethanol (P < 0.001), when compared with the control. A statistical significance (P < 0.001) in two-way ANOVA test indicated that there might be an interactive mechanism between ethanol and ketamine acting on the cerebellum.

Interim follow-up of a randomized controlled trial comparing Chinese style mind body (Tai Chi) and stretching exercises on cognitive function in subjects at risk of progressive cognitive decline

OBJECTIVES

We reported the interim findings of a randomized controlled trial (RCT) to examine the effects of a mind body physical exercise (Tai Chi) on cognitive function in Chinese subjects at risk of cognitive decline.

SUBJECTS

389 Chinese older persons with either a Clinical Dementia Rating (CDR 0.5) or amnestic-MCI participated in an exercise program. The exercise intervention lasted for 1 year; 171 subjects were trained with 24 forms simplified Tai Chi (Intervention, I) and 218 were trained with stretching and toning exercise (Control, C). The exercise comprised of advised exercise sessions of at least three times per week.

RESULTS

At 5th months (2 months after completion of training), both I and C subjects showed an improvement in global cognitive function, delayed recall and subjective cognitive complaints (paired t-tests, p < 0.05). Improvements in visual spans and CDR sum of boxes scores were observed in I group (paired t-tests, p < 0.001). Three (2.2%) and 21(10.8%) subjects from the I and C groups progressed to dementia (Pearson chi square = 8.71, OR = 5.34, 95% CI 1.56-18.29). Logistic regression analysis controlled for baseline group differences in education and cognitive function suggested I group was associated with stable CDR (OR = 0.14, 95%CI = 0.03-0.71, p = 0.02).

CONCLUSIONS

Our interim findings showed that Chinese style mind body (Tai Chi) exercise may offer specific benefits to cognition, potential clinical interests should be further explored with longer observation period.

Expanded polyglutamine domain possesses nuclear export activity which modulates subcellular localization and toxicity of polyQ disease protein via exportin-1

Polyglutamine (polyQ) diseases are a group of late-onset, progressive neurodegenerative disorders caused by CAG trinucleotide repeat expansion in the coding region of disease genes. The cell nucleus is an important site of pathology in polyQ diseases, and transcriptional dysregulation is one of the pathologic hallmarks observed. In this study, we showed that exportin-1 (Xpo1) regulates the nucleocytoplasmic distribution of expanded polyQ protein. We found that expanded polyQ protein, but not its unexpanded form, possesses nuclear export activity and interacts with Xpo1. Genetic manipulation of Xpo1 expression levels in transgenic Drosophila models of polyQ disease confirmed the specific nuclear export role of Xpo1 on expanded polyQ protein. Upon Xpo1 knockdown, the expanded polyQ protein was retained in the nucleus. The nuclear disease protein enhanced polyQ toxicity by binding to heat shock protein (hsp) gene promoter and abolished hsp gene induction. Further, we uncovered a developmental decline of Xpo1 protein levels in vivo that contributes to the accumulation of expanded polyQ protein in the nucleus of symptomatic polyQ transgenic mice. Taken together, we first showed that Xpo1 is a nuclear export receptor for expanded polyQ domain, and our findings establish a direct link between protein nuclear export and the progressive nature of polyQ neurodegeneration.

Impact of income and education on drug purchasing decisions in Hong Kong Chinese cancer patients: a pilot study

BACKGROUND

The affordability of diagnostic, preventive and therapeutic interventions is a global concern, particularly in the developing world. To clarify the educational and financial factors that influence purchasing decisions, we conducted a survey of Hong Kong cancer patients across a broad social spectrum.

METHODS

A questionnaire was designed to assess the effect of costs on purchasing decisions relating to six drug-related variables: efficacy, tolerability, convenience, safety, peer pressure, and uncertainty. Validation of the original 31-part survey resulted in a final set of 22 core questions that was administered to 51 consecutive oncology patients who were characterized in terms of varying household income and educational level.

RESULTS

Most respondents (87.6%) were Hong Kong-born or mainland Chinese. There was a strong correlation between household income and education. Demand for drug tolerability and safety was high and cost-inelastic across all educational and income groups. An unexpected finding was that patients from low-income/education households were keen to purchase costly medications (whether Western, or Chinese herbs) of reputed high efficacy, whereas patients from middle-income/-education backgrounds were more negatively influenced by considerations of cost. Only the most affluent and well-educated patients valued overall survival above disease-free survival when making drug purchasing decisions; this cohort was also the least influenced by peer pressure, and the most willing to pay extra for drugs offering more convenience alone.

CONCLUSION

Low-income/education Asian patients had paradoxically high expectations of costly drug interventions. Although larger studies addressing this issue are needed to confirm these conclusions, public education initiatives aimed at protecting low-income/education patients from exploitation or disappointment may be desirable.

Sequential introduction of single room isolation and hand hygiene campaign in the control of methicillin-resistant Staphylococcus aureus in intensive care unit

Background

After renovation of the adult intensive care unit (ICU) with installation of ten single rooms, an enhanced infection control program was conducted to control the spread of methicillin-resistant Staphylococcus aureus (MRSA) in our hospital.

Methods

Since the ICU renovation, all patients colonized or infected with MRSA were nursed in single rooms with contact precautions. The incidence of MRSA infection in the ICU was monitored during 3 different phases: the baseline period (phase 1); after ICU renovation (phase 2) and after implementation of a hand hygiene campaign with alcohol-based hand rub (phase 3). Patients infected with extended spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella species were chosen as controls because they were managed in open cubicles with standard precautions.

Results

Without a major change in bed occupancy rate, nursing workforce, or the protocol of environmental cleansing throughout the study period, a stepwise reduction in ICU onset nonbacteraemic MRSA infection was observed: from 3.54 (phase 1) to 2.26 (phase 2, p = 0.042) and 1.02 (phase 3, p = 0.006) per 1000-patient-days. ICU onset bacteraemic MRSA infection was significantly reduced from 1.94 (phase 1) to 0.9 (phase 2, p = 0.005) and 0.28 (phase 3, p = 0.021) per 1000-patient-days. Infection due to ESBL-producing organisms did not show a corresponding reduction. The usage density of broad-spectrum antibiotics and fluoroquinolones increased from phase 1 to 3. However a significant trend improvement of ICU onset MRSA infection by segmented regression analysis can only be demonstrated when comparison was made before and after the severe acute respiratory syndrome (SARS) epidemic. This suggests that the deaths of fellow healthcare workers from an occupational acquired infection had an overwhelming effect on their compliance with infection control measures.

Conclusion

Provision of single room isolation facilities and promotion of hand hygiene practice are important. However compliance with infection control measures relies largely on a personal commitment, which may increase when personal safety is threatened.

Getting lost in the community: a phone survey on the community-dwelling demented people in Hong Kong

OBJECTIVE

Research from Western countries reported that the incidence rate of dementia patients getting lost in the community ranged from 30 to 60%. It had imposed significant burden on the caregivers. In the current study, we investigated the situation on the incidents of getting lost in a densely populated as well as homogenous community environment.

METHODS

Two hundred and fifty one caregivers of older adults with demented people who had either used dementia day care service or participated in a community survey were interviewed on the telephone. Respondents were asked on older adult's experience of getting lost in the community and their mode of care. Correlating factors of such incidents were examined.

RESULTS

The overall prevalence of lost history in our subjects was 27.5%. The subjects recruited from day care center were much more likely than those recruited from the community survey to have lost history (39.2% vs. 7.5%, p < 0.0001, chi(2) test). Greater degrees of cognitive decline were associated with greater chance of having had lost episodes. Immobility was associated with lower risk. Both the older people and their caregivers had reported significant degrees of psychological disturbances after the incidents.

CONCLUSION

Demented people with greater degrees of cognitive decline and with mobility maintained are at greater risk of getting lost.

GABA(A) receptor subtype selectivity underlying anxiolytic effect of 6-hydroxyflavone

6-Hydroxyflavone (6HF), a naturally occurring flavonoid, was previously reported to bind to type A gamma-aminobutyric acid (GABA(A)) receptors benzodiazepine (BZ) site with moderate binding affinity. In the present study, we showed that 6HF partially potentiated GABA-induced currents in native GABA(A) receptors expressed in cortical neurons via BZ site, as the enhancement was blocked by the antagonist flumazenil. Furthermore, in patch clamp studies, 6HF displayed significant preference for alpha(2)- and alpha(3)-containing subtypes, which were thought to mediate anxiolytic effect, compared to alpha(1)- and alpha(5)-containing subtypes expressed in HEK 293T cells. In mice, 6HF exhibited anxiolytic-like effect in the elevated plus-maze test, unaccompanied at anxiolytic doses by the sedative, cognitive impairing, myorelaxant, motor incoordination and anticonvulsant effects commonly associated with classical BZs when tested in the hole-board, step-through passive avoidance, horizontal wire, rotarod, and pentylenetetrazol (PTZ)-induced seizure tests, respectively. The findings therefore identified 6HF as a promising drug candidate for the treatment of anxiety-like disorders.

Modality of physical exercise and cognitive function in Hong Kong older Chinese community

OBJECTIVE

We reported the association between modality of Physical Exercise and cognitive function in 782 older Chinese adults assessed in the second phase of a population survey for dementia in Hong Kong.

METHODS

Profiles of physical exercise was measured by a questionnaire (no exercise, stretching, aerobic and mind-body exercise). Cognitive Assessments included the CMMSE, ADAS-Cog, and Category Verbal Fluency Test (CVFT).

RESULTS

The aerobic and mind body exercise groups with longer exercise habits (>5 years) had higher scores in most cognitive tests (Kruskal Wallis tests, p < 0.01). Beneficial effects were more significant in the young old group from 65- 75 years.

CONCLUSIONS

Possible age related specific effects of aerobic and mind body exercise on cognitive reserve are worthy of further exploration.

Human receptor for activated protein kinase C1 associates with polyglutamine aggregates and modulates polyglutamine toxicity

Formation of SDS-insoluble protein aggregates in affected neurons is a cellular pathological feature of polyglutamine (polyQ) disease. We identified a multi-WD-domain protein, receptor for activated protein kinase C1 (RACK1), as a novel polyQ aggregate component from a Drosophila transgenic polyQ disease model. We showed that WD domains were crucial determinants for the recruitment of RACK1 to polyQ aggregates. Over-expression of the human RACK1 protein suppressed polyQ-induced neurodegeneration in vivo. This is the first report to demonstrate the involvement of WD-domain proteins in polyQ pathogenesis, and the proteomic approach described here can be applied to the investigation of other protein aggregation disorders including Alzheimer's and Parkinson's diseases.

Clinical correlates of Parkinsonian signs in community- dwelling Chinese older persons: a population based study

BACKGROUND AND OBJECTIVE

This study examined the clinical correlates of parkinsonian signs including neuropsychiatric symptoms, cognitive impairment and medical illness burden in the community-dwelling non-demented Chinese elderly.

METHODS

A random sample of 765 Chinese elderly subjects from a thematic household survey was recruited. There were 389 normal elderly controls (Clinical Dementia Rating [CDR] 0) (NC) and 376 subjects with questionable dementia (CDR 0.5). The subjects with questionable dementia (CDR 0.5) were categorized into two groups: a MCI group (n = 291) and a very mild dementia (VMD) group (n = 85). Parkinsonian signs were measured by Unified Parkinson Disease Rating Scale- motor scale (UPDRS). The clinical correlates were investigated in each group.

RESULTS

UPDRS motor score was associated with age, cumulative medical illness burden and cerebrovascular accidents in the normal control and MCI groups. It correlated negatively with MMSE scores in the NC group. It was associated with presence of soft signs in the NC and MCI groups; and apathy in the VMD group.

CONCLUSION

Neuropsychiatric symptoms, cognitive impairment and vascular risk factors had different patterns of associations with parkinsonian signs in the older persons with different degree of cognitive impairment.