Revisiting a (001)-oriented layered lead chloride templated by 1,2,4-triazolium: structural phase transitions, lattice dynamics and broadband photoluminescence

This study revisits a (001)-oriented layered lead chloride templated by 1,2,4-triazolium, Tz2PbCl4, which recently has been an object of intense research but still suffers from gaps in characterization. Indeed, the divergent reports on the crystal structures of Tz2PbCl4 at various temperatures, devoid of independent verification of chiral phases through second harmonic generation (SHG), have led to an unresolved debate regarding the existence of a low-temperature phase transition (PT) and the noncentrosymmetric nature of the low-temperature phase. Now, by combining differential scanning calorimetry, single-crystal X-ray diffraction, dielectric, as well as linear and nonlinear optical spectroscopies on Tz2PbCl4, we reveal a sequence of reversible PTs at T1 = 361 K (phase I-II), T2 = 339 K (phase II-III), and T3 = 280 K (phase III-IV). No SHG activity could be registered for any of the four crystal phases, as checked by wide-temperature range SHG screening, supporting their centrosymmetry. The dipole relaxation processes indicate a decrease in activation energy with increasing temperature, from 0.60, 0.38, to 0.24 eV observed for phase IV (space group P21/c), phase III (Pnma), and phase II (Cmcm), respectively. This change is interpreted as a result of the diminishing strength of H-bonds as the system transforms from phase IV to III and subsequently to II. The weaker H-bonds facilitate the reorientation of Tz+ cations in the presence of an external electric field. The photoluminescence spectra of Tz2PbCl4 reveal an intriguing interplay of narrow and broadband emission, linked respectively to free excitons and excitons trapped on defects. Notably, as the temperature decreases from 300 K to 16 K, both the emission bands exhibit distinctive blue and red shifts, indicative of increased in-plane octahedral distortion. This dynamic behaviour transforms the photoluminescence of Tz2PbCl4 from greenish-blue at 300 K to yellowish-green at 13 K, enriching our understanding of 2D lead halide perovskites and highlighting the optoelectronic potential of Tz2PbCl4.

Posttraumatic stress disorder in people with dementia: study protocol

Background: Posttraumatic stress disorder (PTSD) is considered an independent risk factor for dementia. Despite the (clinical) evidence that PTSD is associated with neuropsychiatric symptoms in people with dementia, studies on its prevalence and clinical manifestation are limited, and their quality is affected by the lack of a structured method to diagnose PTSD in this population. The primary aim of the current study is to validate the 'TRAuma and DEmentia' interview as a diagnostic tool for PTSD in people with dementia and to test feasibility of EMDR treatment for people with PTSD and dementia.Methods: This prospective multi-centre study is divided into two parts. In study A, 90 participants with dementia will be included to test the criterion validity, inter-rater reliability and feasibility of the 'TRAuma and DEmentia' interview. In study B, 29 participants with dementia and PTSD will receive eye movement desensitisation and reprocessing therapy by a trained psychologist, and 29 participants with dementia and PTSD will be placed on the waiting list control group.Conclusion: This study aims to improve the diagnostic process of PTSD and to assess the effects of eye movement desensitisation and reprocessing treatment in people with dementia living in Dutch care facilities.Trial registration: NL70479.068.20 / METC 20-063 / OSF registration: https://doi.org/10.17605/OSF.IO/AKW4F.

History of the hip joint pectineofoveal fold

Although Josias Weitbrecht described the retinacula of the hip joint in his 1742 Syndesmologia, the anatomist Cesare Amantini of Perugia specifically studied the medial retinacula he referred to as the pectineofoveal fold in a late 19th-century monograph. This particular synovial fold stretches from the lesser trochanter to the osteocartilaginous junction of the femoral head along a virtual line connecting the lesser trochanter and the fovea for the ligament of the head. Although mentioned by some anatomists and radiologists, and despite its possible involvement in specific hip joint pathologies (fractures, impingements), it is surprising that Amantini's pectineofoveal fold remains ignored by most anatomy and clinical anatomy books. This study aims to verify if Cesare Amantini effectively drew attention to this synovial fold for the first time and coined the term "pectineofoveal fold," as well as determine whether most classical textbooks (i.e., published from 1890 to 2017) acknowledge the discovery and include it in the description of the hip joint. A possible evolutionary link between this synovial fold and the ambiens and pectineus muscles exists and should be discussed.

Unexpected rearrangement of ivermectin in the synthesis of new derivatives with trypanocidal and antiplasmodial activities

Ivermectin is a sixteen-membered macrolactone "wonder drug" of Nobel prize-honored distinction that exhibits a wide range of antiparasitic activities. It has been used for almost four decades in the treatment of various parasitic diseases in humans and animals. In this paper, we describe the synthesis of the first-in-class ivermectin derivatives obtained via derivatization of the C13 position, along with the unexpected rearrangement of the oxahydrindene (hexahydrobenzofuran) unit of the macrolide ring. The structural investigation of the rearrangement has been performed using the single-crystal X-ray diffraction method. The antiparasitic and cytotoxic activities of the newly synthesized derivatives were determined in vitro with the bloodstream form of Trypanosoma brucei brucei, the hepatic stage of Plasmodium berghei, and human leukemia HL-60 cells. The compounds with the highest trypanocidal activity were the C13-epi-2-chloroacetamide analogs of native (6h) or rearranged (7h) ivermectin. Both 6h and 7h displayed trypanocidal activities within a similar mid-nanomolar concentration range as the commercially used trypanocides suramin and ethidium bromide. Furthermore, 6h and 7h exhibited a comparable cytotoxic to trypanocidal ratio as the reference drug ethidium bromide. The double-modified compound 7a (C13-epi-acetamide of rearranged ivermectin) exhibited the highest activity against P. berghei grown in human hepatoma cells, which was 2.5 times higher than that of ivermectin. The findings of this study suggest that C13-epi-amide derivatives of ivermectin are suitable leads in the rational development of new antiparasitic agents.

Treatment of post-traumatic stress disorder in people with dementia: a structured literature review

Post-traumatic stress disorder (PTSD) is associated with cognitive dysfunctions and is an independent risk factor for dementia. A recent study has found the prevalence of PTSD in people with dementia is 4.7%-7.8%. However, little is known about the effectiveness of PTSD treatment for people with dementia. The primary aim of the current study is to review previous studies on the treatment of PTSD in people with dementia. A structured literature review was performed using a 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' analysis in PubMed, Embase, PsycINFO and CINAHL. Two independent researchers screened titles and abstracts. The inclusion criteria were: PTSD symptoms present, diagnosis of dementia, PTSD treatment form described and effects of the treatment mentioned. Articles that matched these criteria were included and content and quality were analyzed. We included nine articles, all case reports, with a total of 11 cases. The discussed treatment options are eye movement desensitisation and reprocessing (EMDR) (n = 3), prolonged exposure (n = 1), cognitive behavioural therapy (n = 1) and pharmacological treatment (n = 4). All articles reported a positive effect of the intervention on several monitored symptoms. Evidence for positive effects and feasibility of EMDR were most reliable, and it was applied in two articles of sufficient quality published in 2018 and 2019. EMDR 'on-the-spot' was described with positive effect in one article in which three cases were discussed. The quality of included papers ranged from insufficient to sufficient. This review shows that people with PTSD and dementia can benefit from PTSD treatment. EMDR, prolonged exposure, acceptance and commitment therapy and pharmacological treatment are applicable in this population. EMDR treatment is most described in this population (n = 5) and shows positive results, and the studies are of sufficient quality (n = 3). Further research in the form of a randomised controlled trial is required to study the effectivity of different treatment interventions in this population.

Treating Symptoms of Posttraumatic Stress in People with Dementia: Expert Consensus Using the Delphi Method

OBJECTIVES

Posttraumatic stress disorder is frequently present in people with dementia, but the symptoms are difficult to recognize and suitable treatments are lacking. The aim of the present study was to investigate which trauma-focused treatments are applicable to these patients.

METHODS

The Delphi method is a process which is used to reach consensus from a panel of experts. The study was conducted online and consisted of three rounds with statements about support for treatment, treatment, and implementation.

RESULTS

There are several treatment options available, but it depends on the symptoms, and the severity of PTSD and dementia which treatment is most suitable.

CONCLUSIONS

The outcomes offer some practical tips for health care workers, and they provide a fundamental base for future research.

CLINICAL IMPLICATIONS

Clinicians should pay attention to the treatment of PTSD symptoms in people with dementia and it is necessary to examine the type and severity of both PTSD symptoms and dementia. Taking these factors into account, clinicians are able to focus on the best treatment option in order to improve the quality of life of these specific type of patients.

[An older patient with depression, anxiety and acute amnesia]

We saw a 73-year-old woman, diagnosed with a recurrent depression and generalized anxiety disorder. Escitalopram had been started by her general practitioner more than seven weeks ago. It was not effective, and was therefore tapered with the aim of starting a different antidepressant. During tapering acute memory problems occurred, presumed to be atypical transient global amnesia. Here we highlight the psychiatric, pharmacological and neurological considerations and differential diagnosis of acute memory disorders.

[Psychopathology in older adults: inter-individual variability, specific presentation and ageism]

Background Geriatric psychiatry is still a relatively young field, but it has made itself indispensable in recent years. This article examines specific features of psychopathology in older adults. Aim To examine what makes older adults ‘different’ compared to younger cohorts. Method Non-systematic literature search. Results Older adults are characterized by a large inter-individual variability, sometimes specific clinical presentation of psychopathology and/or multi-morbidity, including polypharmacy, which results in a specific integrated care with attention to age-specific adjustments in the treatment. Conclusion Psychopathology in older adults requires specialist expertise and multidisciplinary collaboration. In order to optimally treat older adults, ageism must also be tackled thoroughly.

Solvent-controlled elongation and mechanochemical strain in a metal-organic framework

Under high pressure, crystals of [Zn(m-btcp)₂(bpdc)₂]·2DMF·H₂O, referred to as DMOF are particularly sensitive to the type of pressure-transmitting media (PTM) employed: large PTM molecules seal the pores and DMOF is compressed as a closed system, whereas small PTM molecules are pushed into the pores, thereby altering the stoichiometry of DMOF. Compression in glycerol and Daphne 7474 leads to negative linear compressibility (NLC), while a mixture of methanol : ethanol : water 'hyperfills' the pores of the chiral framework, adjusting its 3-dimensional strain and resulting in pressure-induced amorphization around 1.2 GPa. The uptake of the small-molecule PTM strongly increases the dimensions of DMOF in the direction perpendicular to that of the NLC of the crystal.

Musculoskeletal ultrasound for 3D bone modeling: A preliminary study applied to lumbar vertebra

BACKGROUND

There is no non-invasive in vivo method to assess intervertebral kinematics. Current kinematics models are based on in vitro bone reconstructions from computed tomography (CT)-scan imaging, fluoroscopy and MRIs, which are either expensive or deleterious for human tissues. Musculoskeletal ultrasound is an accessible, easy to use and cost-effective device that allows high-resolution, real-time imaging of bone structure.

OBJECTIVE

The aim of this preliminary study was to compare the concordance of 3D bone modeling of lumbar vertebrae between CT-scan and ultrasound imaging and to study the intra and inter-reliability of distances measured on 3D ultrasound bone models.

METHODS

CT-scan, ultrasound, and in situ data of five lumbar vertebrae from the same human specimen were used. All vertebrae were scanned by tomography and a new musculoskeletal ultrasound procedure. Then, 3D bone modeling was created from both CT-scan and ultrasound image data set. Distances between anatomical bones landmarks were measured on the 3D models and compared to in situ measurements.

Stepwise Stress-Induced Transformations of Metal-Organic Polyhedral Cluster-Based Assemblies: Where Conformational and Supramolecular Features Meet

Understanding the factors governing the formation of supramolecular structures and phase transitions between various forms of molecular crystals is pivotal for developing dynamic, stimuli-responsive materials and polymorph-controlled syntheses. Here, we investigate the pressure-induced dynamic of both the intrinsic molecular structure and the supramolecular network of a predesigned polyhedral oxo-centered zinc cluster incorporating monoanionic N,N'-diphenylformamidinate and featuring N-bonded phenyl groups in close proximity to the primary coordination sphere. We demonstrate that the model oxo cluster is prone to undergoing pressure-induced conformational transformations of the secondary coordination sphere and simultaneous stepwise (initially every second polyhedral molecule undergoes the conformational transformations) and reversible transitions from an ambient phase α to high-pressure phases β and γ, as single-crystal-to-single-crystal events. The observed phase transitions illustrate the key role of an interplay between the low-energy conformation perturbations and cooperative intra- and intermolecular noncovalent interactions.

Photoinduced Skeletal Rearrangement of N-Substituted Colchicine Derivatives

Colchicine is an active pharmaceutical ingredient widely used for treating gout, pericarditis, and familial Mediterranean fever with high antimitotic activity. The photoisomerization of colchicine deactivates its anti-inflammatory and antimitotic properties. However, despite numerous reports on colchicine derivatives, their photostability has not been investigated in detail. This report reveals the effects of UV-induced rearrangement on the structure and reports the biological activity of new N-substituted colchicine derivatives.

High-pressure Nucleation of Low-Density Polymorphs*

New polymorphs β and γ of bis-3-nitrophenyl disulphide, crystallized above 0.3 GPa, are less dense than the ambient-pressure polymorph α. This counterintuitive density relation results from the high-entropy nucleation and subsequent kinetic crystallization. The work performed by pressure compensates the high entropy and temperature product, substantiated in varied conformers and increased chemical potential. Pressure-increased viscosity promotes the kinetic polymorphs, in accordance with empirical Ostwald's rule of stages. It contrasts to mechanochemical techniques, favouring high-density polymorphs.

High-pressure Nucleation of Low-Density Polymorphs

Invited for the cover of this issue is the group of Andrzej Katrusiak at Adam Mickiewicz University. The image depicts a wave and the sun, which represent the high energy required for the high-entropy nucleation reported in this work. Read the full text of the article at 10.1002/chem.202005121.

Large negative linear compressibility of a porous molecular co-crystal

Flexible and transformable molecules, particularly those responding to external stimuli, are needed for designing sensors and porous compounds capable of storing or separating gases and liquids. Under normal conditions the photochromic compound, 1,2-bis[2-methyl-5-(pyridyl)-3thienyl]cyclopentene (BTCP) forms a porous co-crystal with 1,4-diiodotetrafluorobenzene (dItFB). It traps acetone (Ac) molecules in the pores. Owing to a unique system of pores in the polar framework, the crystal is sensitive to the humidity in the air and to the chosen liquid environment. When compressed in non-penetrating media, the crystal displays a strong negative linear compressibility (NLC) along [100].

Synthesis and Antiproliferative Screening Of Novel Analogs of Regioselectively Demethylated Colchicine and Thiocolchicine

Colchicine, a pseudoalkaloid isolated from Colchicum autumnale, has been identified as a potent anticancer agent because of its strong antimitotic activity. It was shown that colchicine modifications by regioselective demethylation affected its biological properties. For demethylated colchicine analogs, 10-demethylcolchicine (colchiceine, 1) and 1-demethylthiocolchicine (3), a series of 12 colchicine derivatives including 5 novel esters (2b–c and 4b–d) and 4 carbonates (2e–f and 4e–f) were synthesized. The antiproliferative activity assay, together with in silico evaluation of physicochemical properties, confirmed attractive biological profiles for all obtained compounds. The substitutions of H-donor and H-acceptor sites at C1 in thiocolchicine position provide an efficient control of the hydration affinity and solubility, as demonstrated for anhydrate 3, hemihydrate 4e and monohydrate 4a.

Synthesis and Anticancer Activity of Tertiary Amides of Salinomycin and Their C20-oxo Analogues

The polyether ionophore salinomycin (SAL) has captured much interest because of its potent activity against cancer cells and cancer stem cells. Our previous studies have indicated that C1/C20 double-modification of SAL is a useful strategy to generate diverse agents with promising biological activity profiles. Thus, herein we describe the synthesis of a new class of SAL analogues that combine key modifications at the C1 and C20 positions. The activity of the obtained SAL derivatives was evaluated using primary acute lymphoblastic leukemia, human breast adenocarcinoma and normal mammary epithelial cells. One single- [N,N-dipropyl amide of salinomycin (5 a)] and two novel double-modified analogues [N,N-dipropyl amide of C20-oxosalinomycin (5 b) and piperazine amide of C20-oxosalinomycin (13 b)] were found to be more potent toward the MDA-MB-231 cell line than SAL or its C20-oxo analogue 2. When select analogues were tested against the NCI-60 human tumor cell line panel, 4 a [N,N-diethyl amide of salinomycin] showed particular activity toward the ovarian cancer cell line SK-OV-3. Additionally, both SAL and 2 were found to be potent ex vivo against human ER/PR⁺ , Her2^- invasive mammary carcinoma, with 2 showing minimal toxicity toward normal epithelial cells. The present findings highlight the therapeutic potential of SAL derivatives for select targeting of different cancer types.

Gold nanorods as a high-pressure sensor of phase transitions and refractive-index gauge

Gold nanorods (Au NRs), nanospheres and other nanoparticles display numerous superior physicochemical properties, such as resistance to oxidation and aggressive agents, strong enhancement of local electric field and a high absorption coefficient in the visible and near-infrared (NIR) range. The absorption peaks of surface plasmon resonance (SPR) in Au NRs are highly sensitive to their surrounding medium and to its refractive index (RI) changes. However, no applications of NRs for detecting phase transitions have been reported. Here, we show that Au NRs effectively detect phase transitions of compressed compounds, liquid and solid, by measuring their RI. Owing to the direct interaction of the NRs with their surrounding medium, its subtle RI changes can be observed by the use of high-pressure absorption vis-NIR spectroscopy. We have applied a Au NR-based sensor in a diamond anvil cell (DAC) for monitoring the phase transitions of compressed water, its freezing to ice VI and at the subsequent solid-solid phase transition to ice VII, and the monotonic compression and solid-solid phase transitions in urea and thiourea.

Framework and coordination strain in two isostructural hybrid metal–organic perovskites

Compression of DmaNiFor₃ and DmaCoFor₃ has been investigated by single-crystal X-ray diffraction and Raman spectroscopy.

Gafchromic film dosimetry: four years experience using FilmQA Pro software and Epson flatbed scanners

PURPOSE

s: To assess performance of FilmQA Pro software for pre-treatment patient-specific quality assurance (QA), using radiochromic films and two commercial flatbed scanners. To evaluate a novel multichannel approach compared to the classical red channel evaluation.

MATERIAL AND METHODS

Patient films (mostly EBT2 films, one box of EBT3) were digitalized using successively two flatbed scanners: the A4-size Epson V750 and the A3-size Epson 10000XL. Prior to patient dose verification, basic characteristics of films and scanners were investigated. Patient films were analyzed using FilmQA Pro software, which enables to use the signal from all three colour channels (Red, Green, Blue).

RESULTS

Compared to the red channel evaluation, multichannel evaluation presents better passing rates with regard to local gamma index. As expected, we obtained better results using A3-size scanner compared to A4-size scanner, especially when considering large region of interest. An observation of great interest was made for both scanners: after intensive use, a tilting in the blue transmittance profiles appeared in the lamp direction, making multichannel analysis unsuitable for accurate dose evaluation.

In vitro biomechanical study of femoral torsion disorders: effect on moment arms of thigh muscles

BACKGROUND

Lower limb torsion disorders have been considered as a factor inducing gonarthrosis and the three-dimensional effect of the surgical correction is not well reported yet. This paper reports an in vitro study aiming at quantifying the relationships between experimental femoral torsion disorders and moment arms of thigh muscles.

METHODS

Five unembalmed lower limbs were used and fixed on an experimental jig. Muscles were loaded and 6 Linear Variable Differential Transformers were used to measure tendon excursions. Experimental osteotomies were performed to simulate torsions by steps of 6° up to 18°. Moment arms of the main thigh muscles were estimated by the tendon excursion method during knee flexion.

FINDINGS

Moment arms of the tensor of fascia latae, the gracilis and the semitendinosus were significantly influenced by experimental conditions while the rectus femoris, the biceps femoris and the semimembranosus did not show modifications. Medial femoral torsion decreased the moment arm of both the gracilis and the semimembranosus. Opposite changes were observed during lateral femoral torsion. The moment arm of the tensor of fascia latae decreased significantly after 30° of knee flexion for 18° of medial femoral torsion.

INTERPRETATION

Our results showed that medial and lateral femoral torsion disorders induced alterations of the moment arms of the muscles located medially to the knee joint when applied in aligned lower limbs. These results highlight a potential clinical relevance of the effect of femoral torsion alterations on moment arms of muscles of the thigh which may be related, with knee kinematics modifications, to the development of long-term knee disease.

In vitro biomechanical study of femoral torsion disorders: effect on femoro-tibial kinematics

BACKGROUND

Gonarthrosis is a degenerative disease mainly found in elderly persons. Frontal plane deviations are known to induce lateral and medial gonarthrosis. Nevertheless, patients suffer from gonarthrosis without frontal deviations. Lower limb torsions disorders have been considered as a factor inducing lateral and medial gonarthrosis. This paper reports an in vitro study aiming at quantifying the relationships between experimental femoral torsion disorders and femoro-tibial kinematics.

METHODS

Five fresh-frozen lower limbs were used. Specimens were fixed on an experimental jig and muscles were loaded. A six-degree-of-freedom Instrumented Spatial Linkage was used to measure femoro-tibial kinematics. Experimental femoral osteotomies were performed to simulate various degrees of medial and lateral torsion. Internal tibial rotation, abduction/adduction and proximo-distal, medio-lateral and antero-posterior translations were measured during knee flexion.

FINDINGS

Internal tibial rotation and abduction/adduction were significantly influenced (P<0.001) by femoral torsion disorder conditions. Medial femoral torsion increased tibial adduction and decreased internal rotation during knee flexion. Opposite changes were observed during lateral femoral torsion. Concerning translations, medial femoral torsion induced a significant (P<0.05) decrease of medial translation and inversely for lateral femoral torsion. No interactions between femoral torsion disorders and range of motion were observed.

INTERPRETATION

Our results showed that medial and lateral femoral torsion disorders induced alterations of femoro-tibial kinematics when applied in normally aligned lower limbs. These results highlight a potential clinical relevance of the effect of femoral torsion alterations on knee kinematics that may be related to the development of long-term knee disease.

Effects of proximal row carpectomy on wrist biomechanics: a cadaveric study

BACKGROUND

Many studies show good clinical results after proximal row carpectomy. Some biomechanical consequences are documented, but to our knowledge muscle moment arm variations have not previously been quantified.

METHODS

In five fresh-frozen wrist, kinematics and tendon excursions were measured using a 3D electrogoniometer and Linear Variable Differential Transformers (SOLARTRON Inc., AMETEK Advanced Measurement Technology, Inc, 801 South Illinois Avenue, Oak Ridge, TN 37831-2011, USA), respectively, in three conditions: intact wrist, after posterior capsulotomy and after proximal row carpectomy. Mean pivot point, defined as the point whose sum of the squared distances to the helical axes is minimum, wrist range of motion and mean moment arms were measured during dorso-palmar flexion, radioulnar deviation and circumduction movements.

FINDINGS

No alteration of the range of motion was observed. On the other hand, the mean pivot point shifted proximally (6.8-9.1mm) after proximal row carpectomy (p<0.05) for all motions tested and most muscle moment arms decreased significantly after proximal row carpectomy.

INTERPRETATION

The results of this study allow a better understanding of the biomechanical effects of this procedure. The important moment arm reduction and pivot point displacement suggest modifications of joint biomechanical parameters which could influence the functional outcome of PRC.

Lower high-density lipoprotein cholesterol and increased omega-6 polyunsaturated fatty acids in first-degree relatives of bipolar patients

BACKGROUND

Lower serum high-density lipoprotein cholesterol and increased ratio of omega-6/omega-3 fatty acids have been reported in unipolar and bipolar depressed patients. Changes in cholesterol and fatty acids have been suggested to affect membrane viscosity and consequently serotonergic neurotransmitter expression. The goal of this study was to investigate whether lower baseline cholesterol and increased omega-6 and lower omega-3 fatty acids are present in healthy first-degree relatives of bipolar patients compared with controls and whether these changes were associated with neuroendocrine responses to an i.v. tryptophan challenge or mood.

METHOD

Baseline cholesterol, fatty acids and mood were determined in healthy first-degree relatives of patients with bipolar disorders (N = 30) and healthy matched controls (N = 15) (parallel-group design). Prolactin and cortisol were measured following tryptophan infusion.

RESULTS

First-degree relatives showed significantly lower plasma high-density lipoprotein cholesterol and increased total omega-6 fatty acids in phospholipids. Lower total omega-3 and higher total omega-6 fatty acids in phospholipids were positively correlated with peak prolactin response to tryptophan. Lower total omega-3 fatty acids in phospholipids and cholesteryl esters were associated with lower mood.

CONCLUSIONS

Abnormalities of lower plasma high-density lipoprotein cholesterol and increased total omega-6 fatty acids in phospholipids in these subjects are in agreement with findings in bipolar and major depressed patients. Changes in fatty acids show an association with central serotonergic parameters. It is suggested that these abnormalities in cholesterol and fatty acids may constitute a trait marker for bipolar disorders.

Pronounced cognitive deficits following an intravenous L-tryptophan challenge in first-degree relatives of bipolar patients compared to healthy controls

Cognitive impairment has repeatedly been described in bipolar disorders (BD). Serotonin (5-hydroxytryptophan; 5-HT) is possibly involved in these cognitive processes, more particularly in executive functions, learning, memory, and attention. The aim of this study was to investigate serotonergic vulnerability and its relation to cognitive functioning in healthy first-degree relatives of BD patients. We investigated the effects of an intravenous (i.v.) tryptophan (Trp) challenge and placebo on cognitive performance in 30 healthy first-degree relatives of bipolar patients (FH) and 15 matched controls in a double-blind crossover design. A distinction was made between relatives of type I BD patients (FH I) and type II BD patients (FH II). Performances on planning, memory, attention, and psychomotor tasks were assessed 3 h after Trp infusion. After Trp, planning and attention were impaired in FH subjects but not in controls. Independent of Trp, FH subjects showed cognitive deficits on memory, focused and divided attention, and psychomotor performance. FH I subjects showed more pronounced cognitive impairments then FH II and controls. In all groups, Trp impaired memory and psychomotor performance significantly. In conclusions, cognitive deficits in FH following Trp may reflect a central 5-HT vulnerability in frontal brain areas. Independent of Trp, cognitive deficits in FH provide evidence for a trait marker for BD.

Serotonergic dysregulation in bipolar disorders: a literature review of serotonergic challenge studies

OBJECTIVES

Serotonin (5-hydroxytryptamine; 5-HT) and endocrine abnormalities have been repeatedly reported in bipolar disorders (BD). Useful methods to investigate 5-HT responsivity, and the interaction with neuroendocrine functioning, are provided by acute 5-HT challenge and depletion paradigms. In this review 5-HT challenges are limited to paradigms that stimulate 5-HT activity in BD.

METHODS

Literature was searched for in electronic libraries: MEDLINE and PSYCHLIT, period 1966-2001. Papers describing effects of an acute 5-HT challenge on neuroendocrine functioning in BD patients were selected.

RESULTS

Review of the literature revealed 15 studies: five papers described the effects of 5-HT challenges in manic BD patients, four papers in euthymic BD and seven in depressed BD patients. The reviewed 5-HT challenge paradigms are acute administration of oral and intravenous (i.v.) dosage of d,l-fenfluramine, tryptophan, 5-hydroxytryptophan, ipsapirone and buspirone. There were no papers which investigated neuroendocrine effects of m-chlorophenylpiperazine, clomipramine and citalopram in BD patients and were therefore not reviewed.

CONCLUSIONS

The literature on 5-HT challenge procedures in BD shows evidence for a blunted prolactin (PRL) in mania and depression as well as a blunted cortisol in euthymic BD patients. This suggests that in both mania and depression similar changes in the 5-HT system are involved. It is speculated that blunting of cortisol responses in euthymic BD patients may be a result of chronically altered 5-HT functioning, whereas changes in PRL release following 5-HT challenges reflect more state-dependent changes in 5-HT activity. The 5-HT responsivity in BD patients has also been associated with pharmacological treatment, suicidal behaviour, weight loss and age. Recommendations for future research are given.

Effects of acute tryptophan depletion on mood and cortisol release in first-degree relatives of type I and type II bipolar patients and healthy matched controls

Biological vulnerability for bipolar disorders (BD) in relatives of BD patients has not as yet been established. Serotonergic vulnerability was studied, using acute tryptophan depletion (ATD), in healthy first-degree relatives of BD patients and healthy controls. The effects of ATD on mood and cortisol release in 30 healthy adult, lifetime symptom free, unaffected first-degree relatives of BD patients (Family History; FH) were compared with effects in 15 healthy matched controls in a placebo-controlled, double-blind, crossover design. During ATD and placebo, salivary cortisol response was also assessed during a stress-inducing speech task (SIST). First-degree relatives of type II BD patients (FH II) showed an elevation of mood, whereas control subjects and relatives of type I BD patients (FH I) showed a lowering of mood after ATD. ATD was followed by a decrease in cortisol level in both FH subgroups, but not in the controls. The results suggest serotonergic vulnerability that affected mood in FH II subjects and cortisol release in both FH I and FH II subjects.

Cognition following acute tryptophan depletion: difference between first-degree relatives of bipolar disorder patients and matched healthy control volunteers

BACKGROUND

Serotonergic circuits have been proposed to mediate cognitive processes, particularly learning and memory. Cognitive impairment is often seen in bipolar disorders in relation to a possible lowered serotonergic turnover.

METHODS

We investigated the effects of acute tryptophan depletion (ATD) on cognitive performance in healthy first-degree relatives of bipolar patients (FH) (N= 30) and matched controls (N= 15) in a placebo-controlled, double-blind cross-over design. Performance on planning, memory and attention tasks were assessed at baseline and 5 h after ATD.

RESULTS

Following ATD, speed of information processing on the planning task was impaired in the FH group but not in the control group. FH subjects with a bipolar disorder type I relative (FH I) showed impairments in planning and memory, independent of ATD. In all subjects, ATD impaired long-term memory performance and speed of information processing. ATD did not affect short-term memory and focused and divided attention.

CONCLUSIONS

The results suggest serotonergic vulnerability affecting frontal lobe areas in FH subjects, indicated by impaired planning. Biological vulnerability in FH I subjects is reflected in impaired planning and memory performance. In conclusion, the cognitive dysfunctions in FH subjects indicate an endophenotype constituting a possible biological marker in bipolar psychopathology. Serotonin appears to be involved in speed of information processing, verbal and visual memory and learning processes.

Tryptophan depletion impairs memory consolidation but improves focussed attention in healthy young volunteers

Animal and human studies have provided evidence for serotonergic modulation of cognitive processes. However, the exact nature of this relationship is not clear. We used the acute tryptophan depletion (ATD) method to investigate the effects of lowered serotonin synthesis on cognitive functions in 17 healthy young volunteers. The study was conducted according to a placebo-controlled, double-blind, crossover design. Cognitive performance and mood were assessed at baseline and 5 and 9 h after administration of ATD. A specific impairment of word recognition, without effects on short-term memory, occurred during ATD. No memory deficits were seen if ATD was induced after acquisition of new words. The Stroop Test and dichotic listening task demonstrated a modality independent improvement of focussed attention after ATD. Fluency was also improved after ATD. ATD did not alter speed of information processing, divided attention or planning functions. These results indicate that serotonin is essential in the process of long-term memory consolidation, primarily in the first 30 min after acquisition. Improvement of specific cognitive processes by lowered 5-HT function may be linked to the removal of inhibitory actions of 5-HT in the cortex.

Chemical composition and potential hazards of electrocautery smoke

Electrocautery is widely used for dissection of tissues and cauterization of blood vessels. A visible plume of smoke is produced, which has an unpleasant odour and can induce acute and chronic inflammatory changes in the respiratory tract'. Airborne particles arc not effectively filtered or evacuated by operating room scavenging systems and facial masks only offer protection from large particles. Little is known about the chemical composition of this smoke and the health risks to the operating room staff have not been identified.

The aim of this study was to determine the chemical composition of electrocautery smoke produced in the course of standard colorectal surgery.