Antecedents of major depressive, bipolar, and psychotic disorders: A systematic review and meta-analysis of prospective studies

Major depressive, bipolar, or psychotic disorders are preceded by earlier manifestations in behaviours and experiences. We present a synthesis of evidence on associations between person-level antecedents (behaviour, performance, psychopathology) in childhood, adolescence, or early adulthood and later onsets of major depressive disorder, bipolar disorder, or psychotic disorder based on prospective studies published up to September 16, 2022. We screened 11,342 records, identified 460 eligible publications, and extracted 570 risk ratios quantifying the relationships between 52 antecedents and onsets in 198 unique samples with prospective follow-up of 122,766 individuals from a mean age of 12.4 to a mean age of 24.8 for 1522,426 person years of follow-up. We completed meta-analyses of 12 antecedents with adequate data. Psychotic symptoms, depressive symptoms, anxiety, disruptive behaviors, affective lability, and sleep problems were transdiagnostic antecedents associated with onsets of depressive, bipolar, and psychotic disorders. Attention-deficit/hyperactivity and hypomanic symptoms specifically predicted bipolar disorder. While transdiagnostic and diagnosis-specific antecedents inform targeted prevention and help understand pathogenic mechanisms, extensive gaps in evidence indicate potential for improving early risk identification.

Depressive symptoms in youth before and during the COVID-19 pandemic: longitudinal investigation of patterns dependent on age, sex, and family history of mental illness

BACKGROUND

Cross-sectional studies report high levels of depressive symptoms during the COVID-19 pandemic, especially in youth and females. However, longitudinal research comparing depressive symptoms before and during the pandemic is lacking. Little is known about how the pandemic affected individuals with familial history of mental illness. The present study examines the impact of the pandemic on youth depressive symptoms, including offspring of parents with major mood and psychotic disorders.

METHODS

Between March 2018 and February 2020, we measured depressive symptoms in 412 youth aged 5-25 years. We measured depressive symptoms again in 371 (90%) of these youth between April 2020 and May 2022. Two thirds (249) participants had a biological parent with a major mood or psychotic disorder. We tested the effect of the pandemic by comparing depression symptoms before and after March 2020. We examined age, sex, and family history as potential moderators.

RESULTS

We found an overall small increase in youth depressive symptoms (b = 0.07, 95% CI -0.01 to 0.15, p = 0.062). This was driven by an increase in female youth without familial history of mental illness (b = 0.35, 95% CI 0.14 to 0.56, p = 0.001). There was no change in depressive symptoms among offspring of parents with mental illness or males.

CONCLUSIONS

Our results provide reassurance about the wellbeing of children of parents with mental illness during a period of restricted access to resources outside the family. Rather than increasing symptoms in established risk groups, the pandemic led to a redistribution of depression burden towards segments of the youth population that were previously considered to be low-risk.

Preferences for virtual versus in-person mental and physical healthcare in Canada: a descriptive study from a cohort of youth and their parents enriched for severe mental illness

BACKGROUND

Virtual care may improve access to healthcare and may be well suited to digitally connected youth, but experts caution that privacy and technology barriers could perpetuate access inequities. Success of virtual care will depend on its alignment with patient preferences. However, information on preferences for virtual and in-person healthcare is missing, especially for youth. We sought to quantify preferences for and barriers to virtual versus in-person mental and physical healthcare in youth and their parents, including in vulnerable segments of the population such as families with a parent with severe mental illness (SMI).

METHODS

Participants were 219 youth and 326 parents from the Families Overcoming Risks and Building Opportunities for Wellbeing cohort from Canada, of which 61% of youth had at least one parent with SMI. Participants were interviewed about healthcare preferences and access to privacy/technology between October 2021 and December 2022.

RESULTS

Overall, youth reported a preference for in-person mental (66.6%) and physical healthcare (74.7%) versus virtual care or no preference, and to a somewhat lesser degree, so did their parents (48.0% and 53.9%). Half of participants reported privacy/technology barriers to virtual care, with privacy being the most common barrier. Preferences and barriers varied as a function of parent SMI status, socioeconomic status and rural residence.

CONCLUSIONS

The majority of youth and parents in this study prefer in-person healthcare, and the preference is stronger in youth and in vulnerable segments of the population. Lack of privacy may be a greater barrier to virtual care than access to technology.

[Recommendations for Performing Bronchoscopy in Times of the COVID-19 Pandemic - Update 12/2020]

Die Pandemie ausgelöst durch SARS-CoV-19 geht weltweit unverändert mit einer bedeutsamen Morbidität und Mortalität einher, sodass Schutzmaßnahmen zur Verhinderung der Transmission des Virus weiterhin notwendig sind. Mitarbeiter im Gesundheitswesen sind einem höheren Risiko ausgesetzt, und dies gilt insbesondere im Rahmen sog. Aerosol-generierender Verfahren wie der Bronchoskopie. Seit der Veröffentlichung konsentierter Empfehlungen zur Durchführung einer Bronchoskopie unter diesen Bedingungen vor mehr als einem halben Jahr hat sich die Gefahrenlage nicht wesentlich verändert, aber aufgrund des erheblichen Erkenntnisgewinns in der Zwischenzeit war ein Update der Empfehlungen notwendig. Die erneuerten Empfehlungen umfassen u. a. die Verminderung der Aerosolentstehung, den persönlichen Schutz der beteiligten Personen sowie Maßnahmen zur besseren Organisation der Abläufe in der Endoskopie, um eine sichere Durchführung auch in Zeiten von COVID-19 zu gewährleisten.

[Recommendations for Performing Bronchoscopy in Times of the COVID-19 Pandemic]

COVID-19, caused by coronavirus SARS-CoV-2 is a new and ongoing infectious disease affecting healthcare systems worldwide. Healthcare worker are at high risk for COIVD-19 and many have been infected or even died in countries severely affected by COVID-19 like China or Italy. Bronchoscopy causes cough and aerosol production and has to be considered a significant risk for the staff to get infected. Particular recommendations should guide to prevent spreading COVID-19 and to protect healthcare worker when performing a bronchoscopy.

Peripartum interventions resulting in reduced perinatal mortality rates, and birth asphyxia rates, over 18 years in a tertiary centre in South India: a retrospective study

OBJECTIVE

To study the changes in the rates of perinatal mortality, birth asphyxia, and caesarean sections in relation to interventions implemented over the past 18 years, in a tertiary centre in South India.

DESIGN

Retrospective study.

SETTING

Labour and maternity unit of a tertiary centre in South India.

POPULATION OR SAMPLE

Women who gave birth between 2000 and 2018.

METHODS

Information from perinatal audits, chart reviews, and data retrieved from the electronic database were used. Interventions implemented during this time period were audits and training, obstetric re-organisation, and minor changes in staffing and infrastructure.

MAIN OUTCOME MEASURES

Main outcome measures were perinatal mortality rate, birth asphyxia rate, and caesarean section rate.

RESULTS

Perinatal mortality rate decreased from 44 per 1000 births in 2000 to 16.4 per 1000 births in 2018 (P < 0.001). The rates of babies born with birth asphyxia requiring admission to the neonatal unit decreased from 24 per 1000 births in 2001 to 0.7 per 1000 births in 2018 (P < 0.00001). The overall caesarean section rate was maintained close to 30%.

CONCLUSION

In a large tertiary hospital in South India, with 14 000 deliveries per year, a policy of rigorous audits of stillbirths and birth asphyxia, electronic fetal monitoring, and the introduction of standardised criteria for trial of scar, reduced the perinatal mortality and the rate of babies born with birth asphyxia over the past 18 years, without an increase in the caesarean section rate.

TWEETABLE ABSTRACT

Rigorous perinatal audits with training in fetal cardiotocography, decreased birth asphyxia, without a major increase in caesarean rates.

Multisite Concordance of DSC-MRI Analysis for Brain Tumors: Results of a National Cancer Institute Quantitative Imaging Network Collaborative Project

BACKGROUND AND PURPOSE

Standard assessment criteria for brain tumors that only include anatomic imaging continue to be insufficient. While numerous studies have demonstrated the value of DSC-MR imaging perfusion metrics for this purpose, they have not been incorporated due to a lack of confidence in the consistency of DSC-MR imaging metrics across sites and platforms. This study addresses this limitation with a comparison of multisite/multiplatform analyses of shared DSC-MR imaging datasets of patients with brain tumors.

MATERIALS AND METHODS

DSC-MR imaging data were collected after a preload and during a bolus injection of gadolinium contrast agent using a gradient recalled-echo-EPI sequence (TE/TR = 30/1200 ms; flip angle = 72°). Forty-nine low-grade (n = 13) and high-grade (n = 36) glioma datasets were uploaded to The Cancer Imaging Archive. Datasets included a predetermined arterial input function, enhancing tumor ROIs, and ROIs necessary to create normalized relative CBV and CBF maps. Seven sites computed 20 different perfusion metrics. Pair-wise agreement among sites was assessed with the Lin concordance correlation coefficient. Distinction of low- from high-grade tumors was evaluated with the Wilcoxon rank sum test followed by receiver operating characteristic analysis to identify the optimal thresholds based on sensitivity and specificity.

RESULTS

For normalized relative CBV and normalized CBF, 93% and 94% of entries showed good or excellent cross-site agreement (0.8 ≤ Lin concordance correlation coefficient ≤ 1.0). All metrics could distinguish low- from high-grade tumors. Optimum thresholds were determined for pooled data (normalized relative CBV = 1.4, sensitivity/specificity = 90%:77%; normalized CBF = 1.58, sensitivity/specificity = 86%:77%).

CONCLUSIONS

By means of DSC-MR imaging data obtained after a preload of contrast agent, substantial consistency resulted across sites for brain tumor perfusion metrics with a common threshold discoverable for distinguishing low- from high-grade tumors.

HCV viraemia associates with NK cell activation and dysfunction in antiretroviral therapy-treated HIV/HCV-co-infected subjects

The impact of hepatitis C virus (HCV) RNA levels on immune status in chronically HCV mono-infected when compared to HIV/HCV co-infected on antiretroviral therapy (ART) remains poorly understood. A total of 78 African American subjects HCV viraemic/naïve to HCV treatment (33 HCV genotype 1 mono-infected, 45 ART-treated HIV/HCV genotype 1 co-infected) were studied. Clinical and liver enzyme measurements were performed. Whole blood was analysed for immune subset changes by flow cytometry. Peripheral blood mononuclear cells (PBMC) were used for same-day constitutive and in vitro Interferon (IFN)-α-induced signal transducer and activator of transcription (STAT) phosphorylation, K562 target cell lysis and K562 target cell recognition-mediated IFN-γ production. Statistical analysis was performed using R (2.5.1) or JMP Pro 11. While both groups did not differ in the level of liver enzymes, HIV/HCV had higher T-cell activation/exhaustion, and constitutive STAT-1 phosphorylation compared to HCV. In contrast, CD4⁺ FoxP3⁺ CD25⁺ frequency, IFN-αR expression on NK cells, as well as constitutive and IFN-α-induced direct cytotoxicity were lower in HIV/HCV. Linear regression models further supported these results. Finally, increase in HCV viral load and CD4⁺ T-cell count had an opposite effect between the two groups on NK cell activity and T-cell activation, respectively. HCV viral load in ART-treated HIV/HCV co-infection was associated with greater immune activation/exhaustion and NK dysfunction than HCV viral load alone in HCV mono-infection. The more pronounced immune modulation noted in ART-treated HIV-co-infected/untreated HCV viraemic subjects may impact HCV disease progression and/or response to immunotherapy.

Emergence of linezolid- and vancomycin-resistant Enterococcus faecium in a department for hematologic stem cell transplantation

Background

Prevalence of vancomycin-resistant enterococci has increased in Germany. Here, we report the cluster of linezolid- and vancomycin-resistant Enterococcus faecium (LVRE) in a German department for hematologic stem cell transplantation (HSCT).

Methods

In this retrospective analysis we included all patients with LVRE in a university-based department for HSCT in 2014 and 2015. Patients chart reviews were used to investigate the epidemiology and clinical outcome. Available LVRE isolates underwent detailed microbiological characterization and genotyping by pulsed-field gel electrophoresis (PFGE).

Results

In total, 20 patients with LVRE were identified within the observed time period. All except two patients underwent allogeneic HSCT. Surveillance culture results from incoming patients and chart review revealed that 10 of 20 patients were colonized at hospital admission. Eight of 10 patients with in-hospital acquired LVRE had previous linezolid treatment. Analysis of spatio-temporal patterns showed no evidence for LVRE patient-to-patient or environment-to-patient transmission within the HSCT department. In five cases (25 %) LVRE bloodstream infection occurred. Nine LVRE isolates could be saved for characterization. Eight isolates carried vanA, one isolate vanB. PFGE analysis showed that four different LVRE clones were responsible for the cluster. One single genotype was present in six LVRE isolates whereupon the corresponding patients were all referred from the same hospital to the HSCT department.

Conclusions

This is the first report demonstrating the emergence of LVRE in a German HSCT department. (L)VRE screening at patients’ admission and appropriate infection control strategies were sufficient to prevent any transmission. Further studies in this predisposed patient collective are warranted.

Functional Assessment of Older Adults in an Emergency Department

The fast paced nature of emergency medicine often precludes assessment of patient functioning which may have significant consequences for geriatric patients including falls, functional decline and/or hospital re-admission. A rehabilitation consultation service to a hospital emergency department was implemented based on recommendations in the literature that functional assessments and a multidisciplinary approach be used with older adults. A systematic method of targeting and assessing elderly at-risk patients included a safety checklist and a comprehensive functional assessment tool. An observational study of 80 patients receiving functional assessments from rehabilitation professionals is described. Patients with high levels of disability or who lived alone prior to the emergency visit were more likely to be admitted to hospital. This study supports using multidisciplinary efforts and comprehensive functional assessments in emergency departments to guide decision-making about discharge outcome and planning for the health care needs of elderly patients.

Towards an alternative testing strategy for nanomaterials used in nanomedicine: lessons from NanoTEST

In spite of recent advances in describing the health outcomes of exposure to nanoparticles (NPs), it still remains unclear how exactly NPs interact with their cellular targets. Size, surface, mass, geometry, and composition may all play a beneficial role as well as causing toxicity. Concerns of scientists, politicians and the public about potential health hazards associated with NPs need to be answered. With the variety of exposure routes available, there is potential for NPs to reach every organ in the body but we know little about the impact this might have. The main objective of the FP7 NanoTEST project ( www.nanotest-fp7.eu ) was a better understanding of mechanisms of interactions of NPs employed in nanomedicine with cells, tissues and organs and to address critical issues relating to toxicity testing especially with respect to alternatives to tests on animals. Here we describe an approach towards alternative testing strategies for hazard and risk assessment of nanomaterials, highlighting the adaptation of standard methods demanded by the special physicochemical features of nanomaterials and bioavailability studies. The work has assessed a broad range of toxicity tests, cell models and NP types and concentrations taking into account the inherent impact of NP properties and the effects of changes in experimental conditions using well-characterized NPs. The results of the studies have been used to generate recommendations for a suitable and robust testing strategy which can be applied to new medical NPs as they are developed.

Notizen: Di-tert-butylchlorthioarsoran / Di-tert-butylchlorothioarsorane

The preparation of the first chlorodiorganylthioarsorane is reported. Amidodi(tertbutyl)arsine and sulfur react to give amidodi(tert-butyl)thioarsorane, which is converted into chlorodi(tert-butyl)thioarsorane by a solution of HCl in ether. Some reactions of chlorodi(tert-butyl)thioarsorane are described.

[Outbreak with Ralstonia pickettii caused by contaminated magnesium vials]

HISTORY

In February 2013, 5 patients in an intensive care unit (ICU) were found to have positive blood cultures with Ralstonia pickettii within one week. Because all patients got intravenous therapy, improper work of a staff member was suspected. Some days later, a 6th patient was found with a positive blood culture of Ralstonia pickettii in another department of the hospital.

INVESTIGATIONS

Hygienic investigations showed no evidence of failures in preparation of intravenous therapy. All patients were on different intravenous drugs, but every patient had received glucose 5 % and magnesium. We examined samples of glucose and magnesia as well as samples from environment. RESULTS AND COURSE: Glucose and magnesium samples were examined by membrane filter method. Ralstonia pitteckii was detected in some Magnesium vials. We concluded, that contamination of Magnesium vials might have been the reason for blood stream infection of patients. Pharmacists and authorities were informed and all vials were collected and replaced by vials from another company. Later a nationwide recall of Magnesium vials was performed by the producing company. No further Ralstonia pickettii was found in blood cultures in our hospital.

CONCLUSION

Unusual pathogens in blood cultures should lead to reflection of rarer causes such as contamination of medicines.

[Managing EHEC in hospital routine]

BACKGROUND

During May and June 2011 an outbreak of enterohemorrhagic Escherichia coli (EHEC) occurred in Germany. More than 4000 patients were infected of which 800 developed hemolytic uremic syndrome (HUS) as a severe complication. Reports in the press led to great concern in the general population. Many people with diarrhea reported to hospitals in order to exclude EHEC infections.

METHODS

We describe the management of patients with suspected infectious diarrhea at the university hospital of Essen. A hospital with a significant number of immunocompromised patients.

RESULTS

One important measure to handle the surge of contagious patients was to establish a multidisciplinary coordination team under leadership and guidance of the Department of Nephrology and the Department of Hospital Hygiene. Suspected infectious patients were separated in a modified emergency room. A new ward for infectious diseases was established to isolate in-patients.

CONCLUSION

In our hospital the management of EHEC outbreak enabled us to treat these additional infectious patients without hampering the treatment of the other patients. As a result we plan the implementation of a coordination team for future epidemics.

Cognitive performance of GBA mutation carriers with early-onset PD: the CORE-PD study

OBJECTIVE

To assess the cognitive phenotype of glucocerebrosidase (GBA) mutation carriers with early-onset Parkinson disease (PD).

METHODS

We administered a neuropsychological battery and the University of Pennsylvania Smell Identification Test (UPSIT) to participants in the CORE-PD study who were tested for mutations in PARKIN, LRRK2, and GBA. Participants included 33 GBA mutation carriers and 60 noncarriers of any genetic mutation. Primary analyses were performed on 26 GBA heterozygous mutation carriers without additional mutations and 39 age- and PD duration-matched noncarriers. Five cognitive domains, psychomotor speed, attention, memory, visuospatial function, and executive function, were created from transformed z scores of individual neuropsychological tests. Clinical diagnoses (normal, mild cognitive impairment [MCI], dementia) were assigned blind to genotype based on neuropsychological performance and functional impairment as assessed by the Clinical Dementia Rating (CDR) score. The association between GBA mutation status and neuropsychological performance, CDR, and clinical diagnoses was assessed.

RESULTS

Demographics, UPSIT, and Unified Parkinson's Disease Rating Scale-III performance did not differ between GBA carriers and noncarriers. GBA mutation carriers performed more poorly than noncarriers on the Mini-Mental State Examination (p = 0.035), and on the memory (p = 0.017) and visuospatial (p = 0.028) domains. The most prominent differences were observed in nonverbal memory performance (p < 0.001). Carriers were more likely to receive scores of 0.5 or higher on the CDR (p < 0.001), and a clinical diagnosis of either MCI or dementia (p = 0.004).

CONCLUSION

GBA mutation status may be an independent risk factor for cognitive impairment in patients with PD.

The relation between depression and parkin genotype: the CORE-PD study

BACKGROUND

Mutations in parkin are a known genetic risk factor for early onset Parkinson's disease (EOPD) but their role in non-motor manifestations is not well established. Genetic factors for depression are similarly not well characterized. We investigate the role of parkin mutations in depression among those with EOPD and their relatives.

METHODS

We collected psychiatric information using the Patient Health Questionnaire and Beck Depression Inventory II on 328 genotyped individuals including 88 probands with early onset PD (41 with parkin mutations, 47 without) and 240 first and second-degree relatives without PD.

RESULTS

Genotype was not associated with depression risk among probands. Among unaffected relatives of EOPD cases, only compound heterozygotes (n = 4), and not heterozygotes, had significantly increased risk of depressed mood (OR = 14.1; 95% CI 1.2-163.4), moderate to severe depression (OR = 17.8; 95% CI 1.0-332.0), depression (score ≥ 15) on the Beck Depression Inventory II (BDI-II) (OR = 51.9; 95% CI 4.1-657.4), and BDI-II total depression score (β = 8.4; 95% CI 2.4-11.3) compared to those without parkin mutations.

CONCLUSIONS

Relatives of EOPD cases with compound heterozygous mutations and without diagnosed PD may have a higher risk of depression compared to relatives without parkin mutations. These findings support evidence of a genetic contribution to depression and may extend the phenotypic spectrum of parkin mutations to include non-motor manifestations that precede the development of PD.

Olfaction in Parkin heterozygotes and compound heterozygotes: the CORE-PD study

BACKGROUND

While Parkinson disease (PD) is consistently associated with impaired olfaction, one study reported better olfaction among Parkin mutation carriers than noncarriers. Whether olfaction differs between Parkin mutation heterozygotes and carriers of 2 Parkin mutations (compound heterozygotes) is unknown.

OBJECTIVE

To assess the relationship between Parkin genotype and olfaction in PD probands and their unaffected relatives.

METHODS

We administered the University of Pennsylvania Smell Identification Test (UPSIT) to 44 probands in the Consortium on Risk for Early-Onset Parkinson Disease study with PD onset ≤50 years (10 Parkin mutation heterozygotes, 9 compound heterozygotes, 25 noncarriers) and 80 of their family members (18 heterozygotes, 2 compound heterozygotes, 60 noncarriers). In the probands, linear regression was used to assess the association between UPSIT score (outcome) and Parkin genotype (predictor), adjusting for covariates. Among family members without PD, we compared UPSIT performance in heterozygotes vs noncarriers using generalized estimating equations, adjusting for family membership, age, gender, and smoking.

RESULTS

Among probands with PD, compound heterozygotes had higher UPSIT scores (31.9) than heterozygotes (20.1) or noncarriers (19.9) (p < 0.001). These differences persisted after adjustment for age, gender, disease duration, and smoking. Among relatives without PD, UPSIT performance was similar in heterozygotes (32.5) vs noncarriers (32.4), and better than in heterozygotes with PD (p = 0.001).

CONCLUSION

Olfaction is significantly reduced among Parkin mutation heterozygotes with PD but not among their heterozygous relatives without PD. Compound heterozygotes with PD have olfaction within the normal range. Further research is required to assess whether these findings reflect different neuropathology in Parkin mutation heterozygotes and compound heterozygotes.

Attention modulates beta oscillations during prolonged tactile stimulation

The inter-play between changes in beta-band (14-30-Hz) cortical rhythms and attention during somatosensation informs us about where and when relevant processes occur in the brain. As such, we investigated the effects of attention on somatosensory evoked and induced responses using vibrotactile stimulation and magnetoencephalographic recording. Subjects received trains of vibration at 23 Hz to the right index finger while watching a movie and ignoring the somatosensory stimuli or paying attention to the stimuli to detect a change in the duration of the stimulus. The amplitude of the evoked 23-Hz steady-state response in the contralateral primary somatosensory cortex (SI) was enhanced by attention and the underlying dipole source was located 2 mm more medially, indicating top-down recruitment of additional neuronal populations for the functionally relevant stimulus. Attentional modulation of the somatosensory evoked response indicates facilitation of early processing of the tactile stimulus. Beta-band activity increased after vibration offset in the contralateral primary motor cortex (MI) [event-related synchronization (ERS)] and this increase was larger for attended than ignored stimuli. Beta-band activity decreased in the ipsilateral SI prior to stimulus offset [event-related desynchronization (ERD)] for attended stimuli only. Whereas attention modulation of the evoked response was confined to the contralateral SI, event-related changes of beta-band activity involved contralateral SI-MI and inter-hemispheric SI-SI connections. Modulation of neural activity in such a large sensorimotor network indicates a role for beta activity in higher-order processing.

Evaluation of quantitative liver function tests in HIV-positive patients under anti-retroviral therapy

Background and aims

Quantitative tests of liver function (QTLF) which are based on the hepatic metabolism or clearance of test substances have been successfully used to predict prognosis of a variety of different liver diseases. Still sufficient data in HIV-patients under anti-retroviral therapy (ART) are lacking. Therefore, the aim of this prospective study was to investigate if and to what extent ART influences a broad panel of quantitative tests of liver function in patients with HIV-infection.

Patients and methods

Nineteen patients (14 males, 5 females, mean age 40 years) with HIV-infection underwent QTLF including lidocaine half-life test (LHT), galactose elimination capacity (GEC), and indocyanine green clearance (IGC). These tests were performed before and 3 to 6 months after initiation of anti-retroviral therapy. Twenty age-matched healthy, medication-and virus-free adults served as controls.

Results

Lidocaine half-life was significantly lower in HIV-patients without ART. Combining anti-retroviral therapies shifted cytochrome p450 activity back into standard ranges. Galactose elimination capacity as a parameter of cytosolic liver function and indocyanine green clearance as a parameter of liver perfusion were not affected by ART.

Conclusions

QTLF may be a tool to predict prognosis or hepatic complications in HIV-infected patients with liver disease. Early determination of lidocaine half-life seems to be useful - this should be considered during the treatment of HIV-positive individuals.

Magnetoencephalographic study of vibrotactile evoked transient and steady-state responses in human somatosensory cortex

Somatosensory responses to vibrotactile stimulation applied to the index fingertip were recorded with whole-head MEG in eleven healthy young adult participants. Stimulus trains were produced by a pneumatically driven membrane oscillating at 22 Hz for a trial duration of 1 s, separated by interstimulus intervals (ISIs) of 0.5, 1.0, 3.0, and 7.0 s. Data analysis was performed in two frequency bands. Transient onset responses in the lower frequency band (<20 Hz) contained a clearly expressed P50 component. The higher frequency band (18-30 Hz) revealed a gamma-band response (GBR) within the first 200 ms followed by rhythmic activity at the stimulus frequency that continued throughout the stimulus duration, known as the steady-state response (SSR). Dipoles associated with the transient responses and SSRs were localized in two distinct regions within the primary somatosensory cortex (SI), with transient responses located on average 3 mm more medial and inferior than the SSRs. The transient and GBR peak amplitudes increased with ISI, whereas the SSR amplitude showed no ISI dependence. These results may reflect functionally and spatially distinct neural populations. Further investigations are required to assess the implications of these findings for probing the somatosensory system using other functional neuroimaging methods such as fMRI.

Correlates of eye blinking as determined by synthetic aperture magnetometry

OBJECTIVE

To evaluate the spatiotemporal characteristics of ocular and cerebral current sources during voluntary eyeblinking.

METHODS

Whole-head magnetoencephalographic (MEG) recordings were acquired during voluntary blinking in eight healthy adults and analysed using synthetic aperture magnetometry (SAM).

RESULTS

Fronto-temporal MEG sensors showed a large slow wave lasting approximately 400 ms and a small burst of activity with frequencies above 30 Hz at the initiation of the blink. Group maps of blink-related oscillatory activity at frequencies between 1-18 Hz and 32-64 Hz showed increased activity in and around the orbits during the 400 ms following blink onset. Increased oscillatory activity occurred in occipital regions 200 ms after blink onset at frequencies between 18 and 64 Hz.

CONCLUSIONS

Blink-related MEG signals are recorded in the regions of the eyes and in the occipital cortex. The anterior activation is likely a combination of muscle contraction and eyelid currents. Occipital activation likely represents neural processes concerned with re-establishing the visual image after transient ocular occlusion.

SIGNIFICANCE

The possibility of eyeblink-related fields should be considered when interpreting frontal and occipital source activities during SAM analyses.

Efficiency and efficacy of multi-channel gastric electrical stimulation

Gastric electrical stimulation (GES) using single channel has been under investigation for its therapeutic potential for gastroparesis. The aim of this study was to study the efficacy and efficiency of multi-channel GES in accelerating gastric emptying in dogs. The study was performed in eight dogs, and gastric emptying of liquid was assessed in three randomized sessions of control, one-channel GES and four-channel GES. It was found that (i) GES of both one-channel and four-channel was able to completely entrain the slow waves in the entire stomach. However, the stimulation energy required by four-channel GES was only 1% of that required by one-channel GES. (ii) Four-channel, but not one-channel, GES significantly and substantially accelerated gastric emptying. An increase of 121.0 and 93.9% was noted with four-channel GES at 30 and 60 min after the meal, respectively. It was concluded that four-channel GES is substantially more efficient and effective than conventional single-channel GES in improving gastric emptying. It is worthy to explore its therapeutic potential for gastroparesis in clinical settings.

Stimulus Induced Desynchronization of Human Auditory 40-Hz Steady-State Responses

The hypothesis that gamma-band oscillations are related to the representation of an environmental scene in the cerebral cortex after binding of corresponding perceptual elements is currently under discussion. One question is how the sensory system reacts to a fast change in the scene if perceptual elements are rigidly bound together. A reset of the gamma-band oscillation forced by a change in sensory input may dissolve the binding, which then would be re-established for the new sensation. We studied the reset of gamma-band oscillations on the 40-Hz auditory steady-state responses (ASSR) by means of whole-head magnetoencephalography (MEG). The rhythm of 40-Hz AM of a 500-Hz tone evoked the ASSR, and a short noise burst served as a concurrent stimulus. Possible direct interactions of the auditory stimuli were excluded by presenting the noise impulse in a different frequency channel (2,000–3,000 Hz) to the contralateral ear. The concurrent stimulus induced a considerable decrement in the amplitude of ASSR, which was localized in primary auditory cortices. This decrement lasted 250 ms and was significantly longer than the duration of the transient gamma-band response evoked by the noise burst. Thus it could not be explained by any linear superimposition of the responses. The time courses of ASSR amplitude and phase during recovery from the decrement resembled those after stimulus onset, indicating that a new ASSR was built up after the resetting stimulus. The results are discussed as reset of oscillations in human thalamocortical networks.