Dexmedetomidine alleviates sevoflurane-induced neuroinflammation and neurocognitive disorders by suppressing the P2X4R/NLRP3 pathway in aged mice

PURPOSE

Microglia-mediated inflammation is associated with perioperative neurocognitive disorders (PNDs) caused by sevoflurane. Dexmedetomidine has been reported to protect against sevoflurane-induced cognitive impairment. In this study, we investigated the effects and underlying mechanisms of dexmedetomidine on sevoflurane-induced microglial neuroinflammation and PNDs.

METHODS

Wild-type and purinergic ionotropic 4 receptor (P2X4R) overexpressing C57/BL6 mice were intraperitoneally injected with 20 μg/kg dexmedetomidine or an equal volume of normal saline 2 h prior to sevoflurane exposure. The Morris water maze (MWM) test was performed to assess cognitive function. Immunofluorescence staining was employed to detect microglial activation. The expression levels of proinflammatory cytokines were measured by real-time quantitative PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). The protein levels of P2X4R and NOD-like receptor protein 3 (NLRP3) were detected by Western Blotting.

RESULTS

Sevoflurane increased the number of microglia, upregulated the levels of proinflammatory cytokines, elevated the protein levels of P2X4R and NLRP3 in the hippocampus and induced cognitive decline, while pretreatment with dexmedetomidine downregulated the protein levels of P2X4R and NLRP3, alleviated sevoflurane-induced microglial neuroinflammation and improved cognitive dysfunction. Moreover, overexpression of P2X4R weakened the neuroprotective effect of dexmedetomidine.

CONCLUSIONS

Dexmedetomidine protected against sevoflurane-induced neuroinflammation and neurocognitive disorders by suppressing the P2X4R/NLRP3 pathway.

Statin-related neurocognitive disorder: a real-world pharmacovigilance study based on the FDA adverse event reporting system

BACKGROUND

Concerns regarding statin-related neurocognitive disorders have emerged in recent years. However, previous studies have reported inconsistent results. We evaluated the association between statins and neurocognitive disorders using the FDA Adverse Event Reporting System (FAERS).

RESEARCH DESIGN AND METHODS

Data from 2004 to 2022 were obtained from the FAERS database. After deduplication and standardization of drug names, we extracted neurocognitive disorder event (NCDE) cases reported with statins as the suspected drugs. The significant association between statins and NCDE was evaluated using the reporting odds ratio (ROR) and information component.

RESULTS

In total, 6,959 NCDE cases with statins as the primary suspected drugs were identified. Signals were detected in pravastatin (ROR, 1.49; 95% CI: 1.32-1.67), atorvastatin (ROR, 1.39; 95% CI: 1.34-1.44), and simvastatin (ROR, 1.31; 95% CI: 1.25-1.38). Age-stratified analysis showed that (1) in the population aged 65 years and older, signals were detected for atorvastatin, simvastatin, rosuvastatin, pravastatin, lovastatin, fluvastatin, and pitavastatin; and (2) in populations under 65 years of age, signals were detected for atorvastatin, simvastatin, rosuvastatin, pravastatin, and lovastatin.

CONCLUSIONS

This study suggests a significant association between the NCDE and statins, including atorvastatin, simvastatin, and pravastatin. The intensity of the association increased with age.

Changes in Cerebrospinal Fluid, Liver and Intima-media-thickness Biomarkers in Patients with HIV-associated Neurocognitive Disorders Randomized to a Less Neurotoxic Treatment Regimen

The prevalence of neurocognitive impairment in people living with HIV is estimated between 30 and 50%. The pathogenesis of HIV-associated neurocognitive disorders is complex and multifactorial. Aim of the study was to measure the change in CSF biomarkers, Fibroscan and IMT measurements in PLWH with HAND randomized to a less neurotoxic regimen, or continuing their treatment. Adult patients with HAND were screened and enrolled if presenting no major resistance associated mutations, no HIV viral replication, not on efavirenz or darunavir, with R5-tropic HIV and without major confounding conditions. Lumbar puncture, IMT and Fibroscan measurements were performed. After 1:1 randomization to a less neurotoxic regimen consisting of darunavir/cobicistat plus emtricitabine plus maraviroc, or mantaining actual care, tests were repeated after 24 weeks: CSF biomarkes (HIV RNA, tau, p-tau, Beta-amyloid1-42, S100Beta and neopterin) were included. Non-parametric tests (Mann-Whitney and Wilcoxon's) were used. 28 participants completed the study. Male and European ancestry were prevalent; median age was 55 years (51-60). All patients were virally suppressed; median CD4 + count was 626 cell/uL (469-772). Baseline characteristics were similar between the study arms. A significant decrease in CSF p-tau and an increase in CSF neopterin and NFL were observed. We observed a significant reduction in liver stiffness at W24. Despite a small sample size we observed changes in neuromarkers and in hepatic stiffness in patients randomized to the experimental arm. We observed changes in CSF biomarkers (lower phosphorylated-tau and higher neopterin and NFL) that need to be replicated in large cohorts. Subclinical neurotoxicity may be observed in patients with HAND and warrants prospective studies.

Intergenerational Perioperative Neurocognitive Disorder in Young Adult Male Rats with Traumatic Brain Injury

BACKGROUND

The authors tested the hypothesis that the effects of traumatic brain injury, surgery, and sevoflurane interact to induce neurobehavioral abnormalities in adult male rats and in their offspring (an animal model of intergenerational perioperative neurocognitive disorder).

METHODS

Sprague-Dawley male rats (assigned generation F0) underwent a traumatic brain injury on postnatal day 60 that involved craniectomy (surgery) under 3% sevoflurane for 40 min followed by 2.1% sevoflurane for 3 h on postnatal days 62, 64, and 66 (injury group). The surgery group had craniectomy without traumatic brain injury, whereas the sevoflurane group had sevoflurane only. On postnatal day 90, F0 males and control females were mated to generate offspring (assigned generation F1).

RESULTS

Acutely, F0 injury rats exhibited the greatest increases in serum corticosterone and interleukin-1β and -6, and activation of the hippocampal microglia. Long-term, compared to controls, F0 injury rats had the most exacerbated corticosterone levels at rest (mean ± SD, 2.21 ± 0.64 vs. 7.28 ± 1.95 ng/ml, n = 7 - 8; P < 0.001) and 10 min after restraint (133.12 ± 33.98 vs. 232.83 ± 40.71 ng/ml, n = 7 - 8; P < 0.001), increased interleukin-1β and -6, and reduced expression of hippocampal glucocorticoid receptor (Nr3c1; 0.53 ± 0.08 fold change relative to control, P < 0.001, n = 6) and brain-derived neurotrophic factor genes. They also exhibited greater behavioral deficiencies. Similar abnormalities were evident in their male offspring, whereas F1 females were not affected. The reduced Nr3c1 expression in F1 male, but not female, hippocampus was accompanied by corresponding Nr3c1 promoter hypermethylated CpG sites in F0 spermatozoa and F1 male, but not female, hippocampus.

CONCLUSIONS

These findings in rats suggest that young adult males with traumatic brain injury are at an increased risk of developing perioperative neurocognitive disorder, as are their unexposed male but not female offspring.

EDITOR’S PERSPECTIVE

General Anesthesia and the Young Brain: The Importance of Novel Strategies with Alternate Mechanisms of Action

Over the past three decades, we have been grappling with rapidly accumulating evidence that general anesthetics (GAs) may not be as innocuous for the young brain as we previously believed. The growing realization comes from hundreds of animal studies in numerous species, from nematodes to higher mammals. These studies argue that early exposure to commonly used GAs causes widespread apoptotic neurodegeneration in brain regions critical to cognition and socio-emotional development, kills a substantial number of neurons in the young brain, and, importantly, results in lasting disturbances in neuronal synaptic communication within the remaining neuronal networks. Notably, these outcomes are often associated with long-term impairments in multiple cognitive-affective domains. Not only do preclinical studies clearly demonstrate GA-induced neurotoxicity when the exposures occur in early life, but there is a growing body of clinical literature reporting similar cognitive-affective abnormalities in young children who require GAs. The need to consider alternative GAs led us to focus on synthetic neuroactive steroid analogues that have emerged as effective hypnotics, and analgesics that are apparently devoid of neurotoxic effects and long-term cognitive impairments. This would suggest that certain steroid analogues with different cellular targets and mechanisms of action may be safe alternatives to currently used GAs. Herein we summarize our current knowledge of neuroactive steroids as promising novel GAs.

The effect of PCSK9 inhibitors on brain stroke prevention: A systematic review and meta-analysis

BACKGROUND AND AIMS

Although proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been shown to improve cardiovascular outcomes, their effects on brain stroke risk are unclear. The present meta-analysis aimed to evaluate the effects of PCSK9 inhibitors on brain stroke prevention.

METHODS AND RESULTS

We searched PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov for research published until December 30, 2020, to find randomized controlled trials (RCTs) of PCSK9 inhibitors for brain stroke prevention. Relative risk (RR) and 95% confidence intervals (CIs) were used to represent the outcomes. Seven RCTs with 57,440 participants, including 29,850 patients treated with PCSK9 inhibitors and 27,590 control participants, were included. PCSK9 inhibitors were associated with significant reductions in total brain stroke risk (RR, 0.77; 95% CI, 0.67-0.88; P < 0.001) and ischemic brain stroke risk (RR, 0.76; 95% CI, 0.66, 0.89; P < 0.001) in comparison with the control group. There was no significant difference in cardiovascular mortality (RR, 0.95; 95% CI, 0.84-1.07; P = 0.382) and the risk of hemorrhagic brain stroke (RR, 1.00; 95% CI, 0.66-1.51; P = 0.999) between patients treated with PCSK9 inhibitors and controls. PCSK9 inhibitors did not significantly increase the incidence of neurocognitive adverse events (RR, 1.02; 95% CI, 0.81-1.29; P = 0.85). Moreover, subgroup analysis showed no difference in cognitive function disorder risks among different PCSK9 inhibitors and treatment times.

CONCLUSIONS

PCSK9 inhibitors significantly reduced the risk of total brain stroke and ischemic brain stroke without increasing the risk of brain hemorrhage and neurocognitive impairment.

Dose-Related Adverse Drug Events in Neonates: Recognition and Assessment

The efficacy and safety of a drug is dose or exposure related, and both are used to assess the benefit-risk balance of a given drug and ultimately to decide on the specific drug license, including its dose and indication(s). Unfortunately, both efficacy and safety are much more difficult to establish in neonates, resulting in very few drugs licensed for use in this vulnerable population. This review will focus on dose-related adverse events in neonates. Besides the regulatory classification on seriousness, adverse event assessment includes aspects related to signal detection, causality, and severity. Disentangling confounders from truly dose-related adverse drug events remains a major challenge, as illustrated for drug-induced renal impairment, drug-induced liver injury, and neurodevelopmental outcome. Causality assessment, using either routine tools (Naranjo algorithm, World Health Organization's Uppsala Monitoring Center causality tool) or a Naranjo algorithm tailored to neonates, still does not sufficiently and reliably document causality in neonates. Finally, very recently, a first neonatal severity-grading tool for neonates has been developed. Following the development of advanced pharmacokinetic approaches and techniques to predict and assess drug exposure, additional efforts are needed to truly and fully assess dose adverse drug events. To further operationalize the recently developed tools on causality and severity, reference databases on a palette of biomarkers and outcome variables and their covariates are an obvious next step. These databases should subsequently be integrated in modeling efforts to truly explore safety outcome, including aspects associated with or caused by drug dose or exposure.

Beneficial and Adverse Effects of cART Affect Neurocognitive Function in HIV-1 Infection: Balancing Viral Suppression against Neuronal Stress and Injury

HIV-associated neurocognitive disorders (HAND) persist despite the successful introduction of combination antiretroviral therapy (cART). While insufficient concentration of certain antiretrovirals (ARV) may lead to incomplete viral suppression in the brain, many ARVs are found to cause neuropsychiatric adverse effects, indicating their penetration into the central nervous system (CNS). Several lines of evidence suggest shared critical roles of oxidative and endoplasmic reticulum stress, compromised neuronal energy homeostasis, and autophagy in the promotion of neuronal dysfunction associated with both HIV-1 infection and long-term cART or ARV use. As the lifespans of HIV patients are increased, unique challenges have surfaced. Longer lives convey prolonged exposure of the CNS to viral toxins, neurotoxic ARVs, polypharmacy with prescribed or illicit drug use, and age-related diseases. All of these factors can contribute to increased risks for the development of neuropsychiatric conditions and cognitive impairment, which can significantly impact patient well-being, cART adherence, and overall health outcome. Strategies to increase the penetration of cART into the brain to lower viral toxicity may detrimentally increase ARV neurotoxicity and neuropsychiatric adverse effects. As clinicians attempt to control peripheral viremia in an aging population of HIV-infected patients, they must navigate an increasingly complex myriad of comorbidities, pharmacogenetics, drug-drug interactions, and psychiatric and cognitive dysfunction. Here we review in comparison to the neuropathological effects of HIV-1 the available information on neuropsychiatric adverse effects and neurotoxicity of clinically used ARV and cART. It appears altogether that future cART aiming at controlling HIV-1 in the CNS and preventing HAND will require an intricate balancing act of suppressing viral replication while minimizing neurotoxicity, impairment of neurocognition, and neuropsychiatric adverse effects. Graphical abstract Schematic summary of the effects exerted on the brain and neurocognitive function by HIV-1 infection, comorbidities, psychostimulatory, illicit drugs, therapeutic drugs, such as antiretrovirals, the resulting polypharmacy and aging, as well as the potential interactions of all these factors.

CNS Neurotoxicity of Antiretrovirals

The development of novel antiretroviral treatments has led to a significant turning point in the fight against HIV. Although therapy leads to virologic suppression and prolonged life expectancies, HIV-associated neurocognitive disorder (HAND) remains prevalent. While various hypotheses have been proposed to explain this phenomenon, a growing body of literature explores the neurotoxic effects of antiretroviral therapy. Research to date brings into question the potential role of such medications in neurocognitive and neuropsychiatric impairment seen in HIV-positive patients. This review highlights recent findings and controversies in cellular, molecular, and clinical neurotoxicity of antiretrovirals. It explores the pathogenesis of such toxicity and relates it to clinical manifestations in each medication class. The concept of accelerated aging in persons living with HIV (PLWH) as well as potential treatments for HAND are also discussed. Ultimately, this article hopes to educate clinicians and basic scientists about the neurotoxic effects of antiretrovirals and spur future scientific investigation into this important topic. Graphical Abstract.

Influence of genetic factors on long-term treatment related neurocognitive complications, and on anxiety and depression in survivors of childhood acute lymphoblastic leukemia: The Petale study

BACKGROUND

A substantial number of survivors of childhood acute lymphoblastic leukemia suffer from treatment-related late adverse effects including neurocognitive impairment. While multiple studies have described neurocognitive outcomes in childhood acute lymphoblastic leukemia (ALL) survivors, relatively few have investigated their association with individual genetic constitution.

METHODS

To further address this issue, genetic variants located in 99 genes relevant to the effects of anticancer drugs and in 360 genes implicated in nervous system function and predicted to affect protein function, were pooled from whole exome sequencing data of childhood ALL survivors (PETALE cohort) and analyzed for an association with neurocognitive complications, as well as with anxiety and depression. Variants that sustained correction for multiple testing were genotyped in entire cohort (n = 236) and analyzed with same outcomes.

RESULTS

Common variants in MTR, PPARA, ABCC3, CALML5, CACNB2 and PCDHB10 genes were associated with deficits in neurocognitive tests performance, whereas a variant in SLCO1B1 and EPHA5 genes was associated with anxiety and depression. Majority of associations were modulated by intensity of treatment. Associated variants were further analyzed in an independent SJLIFE cohort of 545 ALL survivors. Two variants, rs1805087 in methionine synthase, MTR and rs58225473 in voltage-dependent calcium channel protein encoding gene, CACNB2 are of particular interest, since associations of borderline significance were found in replication cohort and remain significant in combined discovery and replication groups (OR = 1.5, 95% CI, 1-2.3; p = 0.04 and; OR = 3.7, 95% CI, 1.25-11; p = 0.01, respectively). Variant rs4149056 in SLCO1B1 gene also deserves further attention since previously shown to affect methotrexate clearance and short-term toxicity in ALL patients.

CONCLUSIONS

Current findings can help understanding of the influence of genetic component on long-term neurocognitive impairment. Further studies are needed to confirm whether identified variants may be useful in identifying survivors at increased risk of these complications.

Nanoparticulate matter exposure results in neuroinflammatory changes in the corpus callosum

Epidemiological studies have established an association between air pollution particulate matter exposure (PM2.5) and neurocognitive decline. Experimental data suggest that microglia play an essential role in air pollution PM-induced neuroinflammation and oxidative stress. This study examined the effect of nano-sized particulate matter (nPM) on complement C5 deposition and microglial activation in the corpus callosum of mice (C57BL/6J males). nPM was collected in an urban Los Angeles region impacted by traffic emissions. Mice were exposed to 10 weeks of re-aerosolized nPM or filtered air for a cumulative 150 hours. nPM-exposed mice exhibited reactive microglia and 2-fold increased local deposition of complement C5/ C5α proteins and complement component C5a receptor 1 (CD88) in the corpus callosum. However, serum C5 levels did not differ between nPM and filtered air cohorts. These findings demonstrate white matter C5 deposition and microglial activation secondary to nPM exposure. The C5 upregulation appears to be localized to the brain.

Learning, memory deficits, and impaired neuronal maturation attributed to acrylamide

Acrylamide (ACR) is a neurotoxin known to produce neurotoxicity characterized by ataxia, skeletal muscle weakness, cognitive impairment, and numbness of the extremities. Previously, investigators reported that high-dose (50 mg/kg) ACR impaired hippocampal neurogenesis and increased neural progenitor cell death; however, the influence of subchronic environmentally relevant low dose-(2, 20, or 200 μg/kg) ACRs have not been examined in adult neurogenesis or cognitive function in mice. Accordingly, the aim of the present study was to investigate whether low-dose ACR adversely affected mouse hippocampal neurogenesis and neurocognitive functions. Male C57BL/6 mice were orally administered vehicle or ACR at 2, 20, or 200 μg/kg/day for 4 weeks. ACR did not significantly alter the number of newly generated cells or produce neuroinflammation or neuronal loss in hippocampi. However, behavioral studies revealed that 200 μg/kg ACR produced learning and memory impairment. Furthermore, incubation of ACR with primary cultured neurons during the developmental stage was found to delay neuronal maturation without affecting cell viability indicating the presence of developmental neurotoxicity. These findings indicate that although exposure to in vivo low-dose ACR daily for 4 weeks exerted no apparent marked effect on hippocampal neurogenesis, in vitro observations in primary cultured neurons noted adverse effects on learning and memory impairment suggestive of neurotoxic actions.

Withdrawal of penicillamine from zinc sulphate–penicillamine maintenance therapy in Wilson's disease: Promising, safe and cheap

BACKGROUND

Penicillamine, once considered the cornerstone of treatment for Wilson disease (WD), is rather expensive and toxic, and often causes neurological worsening. Zinc sulphate, aiming at the treatment of free-copper toxicosis, has emerged as effective, safe and cheap alternative.

AIM

To assess the effect of withdrawal of penicillamine from maintenance treatment with penicillamine and zinc sulphate.

PATIENTS AND METHODS

45 patients of WD (M:F: 28:17; age at diagnosis: 13.5+/-63 years), on both penicillamine (P) and zinc sulphate (Zn), couldn't continue penicillamine due to financial constraints. Their clinical data, disability and impairment scores (Schwab and England (S&E) score, Neurological Symptom Score (NSS), and Chu staging) and follow-up data of patients maintained only on zinc sulphate were recorded.

RESULTS

Majority of patients (84.4%) had neuropsychiatric manifestations. The mean duration of treatment with penicillamine (P) and zinc sulphate (P+Zn), before stopping penicillamine, was 107.4+/-67.3 months. 40 patients improved variably, while the rest didn't. They received only zinc sulphate for 27.2+/-8.5 months (range: 12 to 34) and 44 patients (97.7%) remained status quo or improved marginally. Only one patient reported worsening in dysarthria. Their disability and impairment scores during combination (penicillamine and zinc sulphate) and Zn alone were: Chu (1.3+/-0.5 vs. 1.5+/-1.9; p=0.4), NSS (1.8+/-3.1 vs. 1.5+/-2.3; p=0.03) and S&E (96.4+/-5.6 vs. 98.6+/-3.5; p=0.03). There were no adverse effects.

CONCLUSIONS

Withdrawal of penicillamine from zinc sulphate/penicillamine maintenance therapy for patients with Wilson's disease was effective, safe and economic, for almost all patients. This retrospective study reiterates that zinc sulphate may be used as a preferred mode of treatment for patients with Wilson's disease.

Cannabis and Ecstasy/MDMA (3,4-methylenedioxymethamphetamine): an analysis of their neuropsychobiological interactions in recreational users

The majority of recreational Ecstasy/MDMA users (90-98%) also take cannabis. This co-drug usage is often viewed as a methodological confound, which needs to be removed statistically. Here we take a rather different approach, and debate the potential complexities of their psychobiological interactions. The ring-substituted amphetamine derivate MDMA (3,4-methylendioxymethamphetmaine, or 'Ecstasy') is a powerful CNS stimulant, whereas cannabis is a relaxant. Their co-usage may reflect opposing effects in three psychobiological areas: arousal, body temperature, and oxidative stress. Firstly MDMA is alerting whereas cannabis is sedating. Secondly MDMA is hyperthermic whereas cannabis is hypothermic. Thirdly MDMA increases oxidative stress whereas cannabinoids are antioxidant. Hence cannabis may modulate the acute and sub-acute reactions to MDMA, reduce the acute hyperthermia induced by MDMA, and ameliorate the oxidative stress caused by MDMA. The limited empirical evidence on each topic will be critically examined. In terms of chronic effects each drug is functionally damaging, so that polydrug users generally display cumulative neurobiological impairments. However in certain aspects their neuropsychobiological effects may interactive rather than additive. In particular, the combined use of cannabis and MDMA may have rather different neuropsychobiological implications, than their separate usage. In order to investigate these potential complexities, future research will need better empirical data on the exact patterns of co-drug usage.

[Late psychopathological manifestation of professional neurointoxications]

A study of 47 firemen exposed to a complex of toxic substances while putting out fire and 46 subjects with chronic mercury intoxications was carried out 5-10 years after the exposure to toxic substances. Along with clinical psychiatric examination, neuropsychological testing was conducted. Non-specificity of mental disorders, polymorphism and progressive development were found. Psychoorganic syndrome with secondary neurotic disturbances proved to be a core feature of mental disorders. It is emphasized that neuropsychological examination or usage of neuropsychological methods during a psychiatric examination are important for practical diagnosis of exogenous organic mental disorders, especially for outpatient examination of corresponding occupational groups.

Safety of implantable contraceptives for women: data from observational studies

Contraceptive implants are registered in over 60 countries and have been used by millions of women for three decades. This article reviews findings from observational studies on the safety of contraceptive implants and examines the risk of specific health outcomes. Fifty-five articles were reviewed, and the body of evidence for each health outcome was summarized. Available evidence suggests that contraceptive implants are safe and, overall, implant users do not experience adverse events at rates higher than women not using implants. With respect to specific outcomes, the evidence suggests no increased risks of pelvic inflammatory disease, decreased bone mineral density, anemia, thrombocytopenia, or death with implant use. The evidence was too limited to draw meaningful conclusions for neoplastic disease, cardiovascular events, and HIV/AIDS. Nonsignificantly elevated associations were reported for diabetes, serious mental disorders, and rheumatoid arthritis. Conditions for which risks were marginally, yet significantly, elevated were hypertension and gall bladder disease.

Endozepine stupor in children

Recurring episodes of stupor in adults have been shown to be related to increased levels of endozepines, which are endogenous ligands for the GABAA receptors. We report here two children presenting with recurrent episodes of stupor associated with fast EEG activity who had increased levels of endozepine-4 in plasma. Mass spectroscopy did not reveal commercially available benzodiazepines. Interictal endozepine-4 levels were normal. In one of the patients, administration of flumazenil (0.25 mg i.v.), a benzodiazepine inverse agonist, induced improvement of consciousness and attenuation of EEG fast activity. In conclusion, children presenting with recurrent episodes of stupor and EEG fast activity should be evaluated for endozepine levels and can be effectively treated with i.v. flumazenil.

Paradoxical normalization in childhood epilepsy

We report 5 children aged 2.5 to 9 years with refractory epilepsy who, in the wake of a change in anti-epileptic drug (AED) regimen, developed paradoxical normalization (PN). Their acute psychiatric symptoms were associated with abrupt seizure cessation and normalization of the EEG. The latency periods between first seizure and advent of psychosis ranged from 1.9 to 7.0 years. Behavioral manifestations were schizophrenialike psychosis in 1, autistic withdrawal in 3, and organic mental syndrome not otherwise specified in 1. PN has heretofore been reported only in adolescents and adults after prolonged periods of poorly controlled seizures. The hypothesized precipitating factors relate to drug-induced changes in neurotransmitter systems.

Evoked potentials and cerebral blood flow in solvent induced psycho-organic syndrome

Epidemiological studies have provided evidence that neuropsychiatric symptoms are induced by long term exposure to solvents; individual diagnosis with psychometric tests, however, is not always possible (for example, when the patient has linguistic difficulties). Therefore evoked potentials and cerebral blood flow were studied in 50 patients occupationally exposed to solvents who were referred to our department and for whom a solvent induced psycho-organic syndrome was suspected. Degree of exposure was evaluated by its duration (mean 13.9, range 1 to 37 years) and its intensity (from an interview). At the group level, P22 and N35 latencies and amplitude N20-P22 of somatosensory evoked potentials were higher in cases than in controls (p < 0.05), whereas there was no difference for brainstem and visual evoked potentials, nor for hemispheric cerebral blood flow (but a higher distribution in the left occipital region was seen in patients, p < 0.05). Some parameters were linked to degree of exposure (amplitude N20-P22 of somatosensory evoked potentials, interpeak latency I-V of brainstem evoked potentials, distribution of cerebral blood flow in the internal frontal left region). At the individual level, these examinations were not of diagnostic value because sensitivity was low.

[Baclofen intoxication in chronic hemodialysis and kidney transplantation]

Fourteen days after renal transplantation, at first gave with good transplant function, a 36-year-old woman developed neurogenic dysfunction of bladder emptying. This was treated with baclofen, 5 mg three times daily by mouth. Between the 7th and 10th treatment day she progressively developed an organic psychotic syndrome and increasing respiratory paralysis after the onset of renal failure, associated with rejection of the transplanted kidney which required dialysis. Plasma concentration of baclofen was 565 ng/ml (therapeutic range 80-400 ng/ml). After discontinuing the drug and renewed haemodialysis the baclofen level rapidly fell and the symptoms receded. In a second case, a 57-year-old man on dialysis developed a thalamic pain syndrome after an intracerebral haemorrhage in the region of the basal ganglia. He was given four times 10 mg baclofen by mouth over 24 hours. 24 hours after the first dose he became deeply unconscious with respiratory failure. Plasma concentration of baclofen after the first haemodialysis period was 480 ng/ml. After 48 hours of artificial ventilation it was possible to extubate; a symptomatic transitory psychotic syndrome disappeared within 4 days. Both patients had pre-existing cerebral damage in addition to the chronic renal failure (in the first patient, meningoencephalitis 30 years previously with persisting focal lesions in the computed tomogram CT]; in the second one, residual lesions in the CT after intracerebral haemorrhage). It is emphasized that in patients who are in renal failure baclofen treatment should be undertaken cautiously: toxic signs can quickly develop especially if there is pre-existing cerebral damage.

The safety profile of paroxetine

Side effects remain one of the most important clinical issues in antidepressant therapy. Patients may not be able to take appropriate treatment or may not tolerate their medication in adequate doses or for an adequate length of time to manage their depressive illness. This article reviews the extensive safety data from 6705 patients treated with paroxetine. These data indicate that paroxetine has no significant cardiovascular effects, few significant drug interactions, and no clinically significant effects on the ECG or EEG. Furthermore, paroxetine is relatively safe in overdose and has very little anticholinergic activity. Psychomotor performance is not impaired by paroxetine and there is no evidence of any zimelidine-like hypersensitivity reactions or increase in suicidal ideation. As with other selective serotonin reuptake inhibitors (SSRIs), the most common side effect is gastrointestinal upset, especially nausea. This is usually very well tolerated and rarely leads to drug discontinuation. As with other SSRIs, monoamine oxidase inhibitors should not be prescribed concurrently or soon after discontinuing paroxetine because of the risk of a lethal interaction. Paroxetine may be less likely than currently available SSRIs to cause agitation. In general, paroxetine has a very favorable side effect profile and should be an important alternative in the medical treatment of depressive illness.

Psychiatric disturbances associated with ganciclovir therapy

OBJECTIVE

To report a case of possible ganciclovir-induced psychiatric disturbances.

CASE SUMMARY

A patient with AIDS who had no known psychiatric history and mild renal dysfunction experienced exacerbation of cytomegalovirus retinitis and was treated with ganciclovir 5 mg/kg iv q12h. The patient complained of nightmares and developed visual hallucinations and severe agitation on day 15 of ganciclovir therapy. The problems resolved after haloperidol administration and ganciclovir withdrawal and reappeared when the same regimen was reinstituted. However, the patient was able to tolerate the maintenance dose of ganciclovir at 5 mg/kg/d along with haloperidol later without further episodes of visual hallucinations.

DISCUSSION

Case reports in the literature on ganciclovir-or its analog, acyclovir-, induced psychiatric disturbances were reviewed and compared. The potential relationship between ganciclovir accumulation in patients with renal insufficiency and the observed central nervous system problems in our patient was postulated.

CONCLUSIONS

It is likely that ganciclovir accumulation contributed to the acute psychotic episodes observed in our patient. Adjusting ganciclovir dosage based on the patient's renal function is probably the only approach required to prevent or reduce the incidence of these episodes.

Postictal psychosis after partial complex seizures: a multiple case study

Bouts of unusually frequent partial complex seizures originating in the temporal lobe, that sometimes became secondarily generalized, induced psychotic episodes in 9 patients. In 7, the increase in seizures occurred at a time when antiepileptic drugs (AEDs) were being reduced during intensive EEG monitoring with a view to surgical treatment of intractable epilepsy. According to DSM-III-R criteria, the postictal psychosis resembled an organic delusional syndrome which was paranoid in 7 and schizophreniform in 1 and an organic mood syndrome in 1. A high incidence of ictal fear, of bilateral independent epileptogenic discharge, and of small foreign tissue lesion were unexpected findings and appeared to represent risk factors, especially in patients otherwise handicapped by an epileptic personality disorder. Recognition of postictal psychosis in this setting and in others is important both prognostically and therapeutically. Postictal psychosis does not constitute a contraindication to surgical treatment of epilepsy.

Psychoorganic syndrome from exposure to fluorocarbon 113--an occupational disease?

A cross-sectional clinical study of 99 workers engaged in degreasing with halogenated hydrocarbons has been carried out. Among 23 cleaners from one factory, all at the time using fluorocarbon 113, we found 3 persons with symptoms and signs of psychoorganic syndrome after heavy exposure to fluorocarbon 113 for 2 1/2-4 1/2 years. The possibility of developing psychoorganic syndrome from occupational exposure to fluorocarbon is discussed by presenting these 3 cases.

Enduring changes in brain and behavior produced by chronic amphetamine administration: a review and evaluation of animal models of amphetamine psychosis

Some people who repeatedly use stimulant drugs, such as amphetamine (AMPH), develop an AMPH-induced psychosis that is similar to paranoid schizophrenia. There has been, therefore, considerable interest in characterizing the effects of chronic stimulant drug treatment on brain and behavior in non-human animals, and in developing an animal model of AMPH psychosis. A review of this literature shows that in non-human animals chronic AMPH treatment can produce at least two different syndromes, and both of these have been proposed as animal models of AMPH psychosis. The first syndrome is called 'AMPH neurotoxicity', and is produced by maintaining elevated brain concentrations of AMPH for prolonged periods of time. AMPH neurotoxicity is characterized by what has been termed 'hallucinatory-like' behavior, which occurs in association with brain damage resulting in the depletion of striatal DA and other brain monoamines. The second syndrome is called 'behavioral sensitization', and is produced by the repeated intermittent administration of lower doses of AMPH. Behavioral sensitization is characterized by a progressive and enduring enhancement in many AMPH-induced behaviors, and is not accompanied by brain damage or monoamine depletion. It is argued that the changes in the brain and behavior associated with the phenomenon of behavioral sensitization provide a better 'model' of AMPH psychosis than those associated with AMPH neurotoxicity. Much of the review involves a critical analysis of hypotheses regarding the biological basis of behavioral sensitization. Research on this question has focused on mesotelencephalic DA systems, and suggestions that behavioral sensitization is accompanied by: an increase in postsynaptic DA receptors; an increase in DA synthesis; an increase in DA utilization and/or release; and a decrease in DA autoreceptors, are evaluated. It is concluded that there is not convincing evidence for an increase in postsynaptic DA receptors or in DA synthesis in animals sensitized to AMPH. In contrast, there is strong evidence to support the notion that behavioral sensitization is due to enhanced mesotelencephalic DA release, especially upon re-exposure to the drug. The evidence that this enhancement in DA release is due to autoreceptor subsensitivity was found to be equivocal, and therefore other hypotheses should be entertained. Lastly, evidence is discussed in support of the idea that behavioral sensitization is not unique to the psychopharmacology of stimulant drugs, but may be produced by many environmental stimuli that directly or indirectly activate brain catecholamine systems.(ABSTRACT TRUNCATED AT 400 WORDS)

Mental disorders after myelography with metrizamide and other water-soluble contrast media

Water-soluble contrast media, which have been employed in the examination of the lumbar spinal canal for 30 years, can sometimes result in severe complications, such as arachnoiditis, epileptic seizures, and myoclonic spasm. These complications have been seen less frequently since the advent of metrizamide, a new non-ionic water-soluble contrast medium. However, a further neurological complication has now arisen--mental disorder, varying in kind and degree; for example, organic psychosis and perceptual disturbance. Some characteristic cases are described. A series of 75 patients, all of whom received varying amounts of metrizamide for the purpose of cervical, thoracic and lumbar myelography, has been studied. Seven patients were found to have a pronounced organic psychosis and three patients had visual illusions or hallucinations. It is suggested that there is some degree of correlation between the total amount of iodine received and patient age. By careful enquiry and examination, similar disturbances were also found some 4-8 h after myelography with other water-soluble contrast media.

Is phencyclidine (PCP) abuse associated with organic mental impairment?

The performance of sober (average length of abstinence = 27 months) phencyclidine (PCP) abusers on neuropsychological measures of organicity was compared to that of polydrug users who were not experienced with PCP, and to controls who were not alcohol or drug abusers. Six of 12 PCP users, five of 12 polydrug users, and none of the controls showed neuropsychological impairments. The deficits in PCP users occurred despite negative medical-neurological history, and even though the PCP group abused other drugs previously associated with neuropsychological impairment less than the polydrug group. Deficiencies in abstracting and in perceptual-motor integrative abilities were noted. The results suggest the possibility that PCP abuse might be associated with neuropsychological disturbance which persists for considerable time after PCP use ceases.

[Non-leukemic disease of the central nervous system in children with acute lymphoblastic leukemia. I. Somnolence syndrome (author's transl)]

Prophylactic irradiation of the skull and intrathecal application of methotrexate has proven to be highly effective in preventing central nervous system disease in acute lymphoblastic leukemia or non-Hodgkin-lymphoma. Prophylactic treatment may be complicated by a somnolence syndrome occuring 4--8 weaks after the end of irradiation. The main features of this clinical entity are somnolence, lethargy, dullness, anorexia, headache, and vomiting. EEG frequently displays a distinct slowing of activity. All symptoms are reversible after 3--49 days. The syndrome clearly is consequence of skull irradiation. Its metabolic basis probably is transient disturbance of myelinization.

Further clinical experiences of a phase I study with the hypoxic cell radiosensitizer misonidazole

Since April 1976 we have performed clinical investigations with multiple doses of the hypoxic cell radiosensitizer misonidazole in 21 patients. A significant side effect of the drug was the development of peripheral sensory neuropathies in 13 patients (8 mild, 5 severe) and of a transient acute organic psychosyndrome in 2 of the 5 patients with a severe polyneuropathy. The severity of the polyneuropathies is related to the total dose of misonidazole and the overall time of drug administration. Treatment schedules designed to obtain the desired sensitizing effect without neurological side effects are under investigation.

[Cerebro-organic syndrome during gold therapy. Possible correlation between gold therapy in chronic seronegative polyarthritis and the appearance of a cerebro-organic syndrome. A case contribution]

In this article the possible relationship between gold therapy of a chronic seronegative polyarthritis and the appearance of a cerebro-organic syndrome in a 56-year-old postmenopausal woman will be discussed. We take into consideration the basic illness, the biography, the hormonal situation, the simultaneous chloroquin therapy and the overdosage of the gold drug. After a careful consideration of the different diagnostical possibilities following the above mentioned factors, not only a temporal but also a causative relationship of gold therapy and cerebro-organic syndrome seems to be possible.

Acute organic brain syndrome associated with gentamicin therapy

Two patients receiving gentamicin sulfate experienced acute organic brain syndromes that subsided after use of the drug was discontinued. Among the various factors considered as possible causes, time sequences point to gentamicin as the most likely.

Epilepsy and schizophrenia: a neurochemical bridge

This paper reviews some of the evidence in the literature that suggests neurochemical processes by which the regulation of seizure threshold and the onset of schizophrenic-like symptoms are interrelated. For those patients who experience the alternation of seizures and acute psychoses the following working hypothesis is presented: The central dopaminergic synapse is described as a malfunctioning regulatory circuit. Insufficient feedback inhibition or lifting of the setpoint leads to an increased number of occupied receptors. This might cause schizophrenic-like symptoms. Insufficient release of feedback control or lowering of the setpoint leads to a decreased number of occupied receptors. This might increase seizure susceptibility. The neurochemical arguments in support of this hypothesis will be discussed in detail. The localization of the dopaminergic synapses involved in the development of schizophrenic-like symptoms is subject to speculation. The meso-limbic dopaminergic system has to be taken into consideration.

Physiological dependence on, and symptoms of withdrawal from, chlormethiazole

The uses of chlormethiazole (Heminevrin) are briefly mentioned. Differing views of its potential for producing dependence are discussed. The consensus opinion is taken to be that a risk of psychological dependence does exist, but only one case has appeared in the medical literature to date of physiological dependence on chlormethiazole, with withdrawal symptoms. This case is re-examined. A second case is described in which the features of increasing dosage and withdrawal were followed by confusion, disorientation, delusions, hallucinations and muscular spasm and coarse jerking. This is taken as confirmation of the potential of chlormethiazole to produce physiological dependence. Some personal opinions of the author regarding indications for use and incidence of abuse are briefly mentioned.

Reversible encephalopathy following cephacetril therapy in high doses in a patient on chronic intermittent hemodialysis

A patient on chronic intermittent hemodialysis at home showed signs of acute encephalopathy after an 8-day's treatment with a total dose of 78 g cephacetril (Celospor). Features included papilledema, loss of visual fields, severe generalized EEG changes and bilateral occipital abnormalities on a brain scintigram. Psychopathological findings consisted of a severe psychosis. The visual fields defects were the last sign of the encephalopathy to disappear.

Lithium intoxication: a report of two cases

Two cases of toxic reaction to lithium carbonate are reported. The first patient displayed symptoms resembling those of organic brain syndrome which was not associated with a high serum lithium level. The influence of diuretic therapy in combination with lithium is felt to enhance the risk of intoxication. The second case depicts acute CNS toxicity with known fatal potential. Conservative lithium administration is recommended for acute manic psychosis and reference is made to the beneficial effects of urea and aminophylline on renal lithium elimination in the active treatment of lithium poisoning.