A Review on Renal Toxicity Profile of Common Abusive Drugs

Drug abuse has become a major social problem of the modern world and majority of these abusive drugs or their metabolites are excreted through the kidneys and, thus, the renal complications of these drugs are very common. Morphine, heroin, cocaine, nicotine and alcohol are the most commonly abused drugs, and their use is associated with various types of renal toxicity. The renal complications include a wide range of glomerular, interstitial and vascular diseases leading to acute or chronic renal failure. The present review discusses the renal toxicity profile and possible mechanisms of commonly abused drugs including morphine, heroin, cocaine, nicotine, caffeine and alcohol.     

A pilot study of the tolerability and effects of high-definition transcranial direct current stimulation (HD-tDCS) on pain perception

Several brain stimulation technologies are beginning to evidence promise as pain treatments. However, traditional versions of 1 specific technique, transcranial direct current stimulation (tDCS), stimulate broad regions of cortex with poor spatial precision. A new tDCS design, called high definition tDCS (HD-tDCS), allows for focal delivery of the charge to discrete regions of the cortex. We sought to preliminarily test the safety and tolerability of the HD-tDCS technique as well as to evaluate whether HD-tDCS over the motor cortex would decrease pain and sensory experience. Twenty-four healthy adult volunteers underwent quantitative sensory testing before and after 20 minutes of real (n = 13) or sham (n = 11) 2 mA HD-tDCS over the motor cortex. No adverse events occurred and no side effects were reported. Real HD-tDCS was associated with significantly decreased heat and cold sensory thresholds, decreased thermal wind-up pain, and a marginal analgesic effect for cold pain thresholds. No significant effects were observed for mechanical pain thresholds or heat pain thresholds. HD-tDCS appears well tolerated, and produced changes in underlying cortex that are associated with changes in pain perception. Future studies are warranted to investigate HD-tDCS in other applications, and to examine further its potential to affect pain perception. PERSPECTIVE: This article presents preliminary tolerability and efficacy data for a new focal brain stimulation technique called high definition transcranial direct current stimulation. This technique may have applications in the management of pain.     

Reversal of SSRI-associated apathy syndrome by discontinuation of therapy

OBJECTIVE : To report 6 cases of selective serotonin reuptake inhibitor (SSRI)-associated apathy syndrome. CASE SUMMARIES : In all 6 cases, the patient reported loss of motivation while being treated with an SSRI. Loss of motivation was of new onset and temporally associated with the use of the SSRI. A trial of discontinuation of the SSRI was performed in all 6 patients and 2 were started on bupropion while cross-tapering from the SSRI. During the treatment trials, depression and apathy were monitored in all patients. Each case was assessed using the Apathy Evaluation Scale, Clinician version (AES-C), and by evaluating how the patient responded to discontinuation of the SSRI. DISCUSSION : Scores on the AES-C improved significantly in all 6 cases after the SSRI was discontinued. Improvement was also seen in the motivation, novelty, and persistence subdomain scores of the AES-C. A pretreatment AES-C score was available only in the first case. Based on the Naranjo probability scale, there was a probable cause of apathy syndrome with SSRI therapy in the first case and a possible association in the rest of the cases. CONCLUSIONS : In some patients SSRIs may cause an apathy syndrome that can be reversed through discontinuation of the agent. When evaluating patients being treated with an SSRI, clinicians should have a high degree of suspicion and specifically inquire for this iatrogenic form of apathy syndrome.     

Creating a Cambodia-specific developmental milestone screening tool - a pilot study

Background

Approximately 600 million people are living with various types of disabilities throughout the world and over 200 million children under age of 5 years old not reach their developmental potential. These adverse outcomes can be prevented through early detection and treatment. To accurately assess the development of children, a culturally appropriate screening tool must be used. Cambodia lacks such tool and other studies have shown that western tools are not valid in other cultures.

Aims

This study aimed at creating a culturally appropriate screening tool – called the Angkor Hospital for Children Developmental Milestone Assessment Tool (AHC DMAT) – for screening neurodevelopmental disability in Cambodian children.

Study design, subject, outcome measures

Western milestones from the DDST II were used with cultural modifications. Children of both genders and aged from 1 month to 6 years assumed to have normal development were included in two pilot screenings (N = 100 and N = 63) with further modifications to the AHC DMAT made as necessary after each screening.

Results

The final AHC DMAT consists of 140 milestones (49% directly from DDST II, 17% modified DDST II, 34% added through expert opinion).

Conclusion

Extensive revision of the DDST II was needed in order to create a more valid Cambodian screening tool. This study was the first step to create a Cambodian-specific screening tool but further large-scale testing of the AHC DMAT is needed to strengthen the tool's validity and to identify the age-range percentiles of each milestone before it can be used for neurodevelopment screening.     

N-methyl D-aspartate (NMDA) receptor antagonists and memantine treatment for Alzheimer's disease, vascular dementia and Parkinson's disease

Memantine, a partial antagonist of N-methyl-D-aspartate receptor (NMDAR), approved for moderate to severe Alzheimer's disease (AD) treatment within the U.S. and Europe under brand name Namenda (Forest), Axura and Akatinol (Merz), and Ebixa and Abixa (Lundbeck), may have potential in alleviating additional neurological conditions, such as vascular dementia (VD) and Parkinson's disease (PD). In various animal models, memantine has been reported to be a neuroprotective agent that positively impacts both neurodegenerative and vascular processes. While excessive levels of glutamate result in neurotoxicity, in part through the over-activation of NMDARs, memantine-as a partial NMDAR antagonist, blocks the NMDA glutamate receptors to normalize the glutamatergic system and ameliorate cognitive and memory deficits. The key to memantine's therapeutic action lies in its uncompetitive binding to the NMDAR through which low affinity and rapid off-rate kinetics of memantine at the level of the NMDAR-channel preserves the physiological function of the receptor, underpinning memantine's tolerability and low adverse event profile. As the biochemical pathways evoked by NMDAR antagonism also play a role in PD and since no other drug is sufficiently effective to substitute for the first-line treatment of L-dopa despite its side effects, memantine may be useful in PD treatment with possibly fewer side effects. In spite of the relative modest nature of its adverse effects, memantine has been shown to provide only a moderate decrease in clinical deterioration in AD and VD, and hence efforts are being undertaken in the design of new and more potent memantine-based drugs to hopefully provide greater efficacy.     

Balloon test occlusion with the Doppler velocity guidewire

Transcranial Doppler ultrasonography is the most commonly used method of cerebrovascular blood flow velocity measurement, but it is subject to certain technical and anatomic limitations. The Doppler velocity guidewire measures blood flow velocity within any vessel during cerebral angiography, overcoming these limitations. We report the first use of this guidewire in the measurement of blood flow velocity during balloon test occlusion, with results similar to simultaneously measured transcranial Doppler ultrasonography. Velocity measurement by Doppler guidewire could be useful in balloon test occlusion for vertebrobasilar circulation, where transcranial Doppler ultrasonography is limited, and provide anatomically specific blood flow velocity measurements in the diagnosis and treatment of stroke and other cerebrovascular diseases.