Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 526
Filtrar
1.
Ann Neurol ; 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949221

RESUMO

OBJECTIVE: Alice in Wonderland syndrome (AIWS) profoundly affects human perception of size and scale, particularly regarding one's own body and the environment. Its neuroanatomical basis has remained elusive, partly because brain lesions causing AIWS can occur in different brain regions. Here, we aimed to determine if brain lesions causing AIWS map to a distributed brain network. METHODS: A retrospective case-control study analyzing 37 cases of lesion-induced AIWS identified through systematic literature review was conducted. Using resting-state functional connectome data from 1,000 healthy individuals, the whole-brain connections of each lesion were estimated and contrasted with those from a control dataset comprising 1,073 lesions associated with 25 other neuropsychiatric syndromes. Additionally, connectivity findings from lesion-induced AIWS cases were compared with functional neuroimaging results from 5 non-lesional AIWS cases. RESULTS: AIWS-associated lesions were located in various brain regions with minimal overlap (≤33%). However, the majority of lesions (≥85%) demonstrated shared connectivity to the right extrastriate body area, known to be selectively activated by viewing body part images, and the inferior parietal cortex, involved in size and scale judgements. This pattern was uniquely characteristic of AIWS when compared with other neuropsychiatric disorders (family-wise error-corrected p < 0.05) and consistent with functional neuroimaging observations in AIWS due to nonlesional causes (median correlation r = 0.56, interquartile range 0.24). INTERPRETATION: AIWS-related perceptual distortions map to one common brain network, encompassing regions critical for body representation and size-scale processing. These findings lend insight into the neuroanatomical localization of higher-order perceptual functions, and may inform future therapeutic strategies for perceptual disorders. ANN NEUROL 2024.

2.
bioRxiv ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38948714

RESUMO

BACKGROUND: Primary hypertension in childhood tracks into adulthood and may be associated with increased cardiovascular risk. Studies conducted in children and adolescents provide an opportunity to explore the early cardiovascular target organ injury (CV-TOI) in a population free from many of the comorbid cardiovascular disease risk factors that confound studies in adults. METHODS: Youths (n=132, mean age 15.8 years) were stratified by blood pressure (BP) as low, elevated, and high-BP and by left ventricular mass index (LVMI) as low- and high-LVMI. Systemic circulating RNA, miRNA, and methylation profiles in peripheral blood mononuclear cells and deep proteome profiles in serum were determined using high-throughput sequencing techniques. RESULTS: VASH1 gene expression was elevated in youths with high-BP with and without high-LVMI. VASH1 expression levels positively correlated with systolic BP (r=0.3143, p=0.0034). The expression of hsa-miR-335-5p, one of the VASH1-predicted miRNAs, was downregulated in high-BP with high-LVMI youths and was inversely correlated with systolic BP (r=-0.1891, p=0.0489). GSE1 hypermethylation, circulating PROZ upregulation (log2FC=0.61, p=0.0049 and log2FC=0.62, p=0.0064), and SOD3 downregulation (log2FC=-0.70, p=0.0042 and log2FC=-0.64, p=0.010) were observed in youths with elevated BP and high-BP with high-LVMI. Comparing the transcriptomic and proteomic profiles revealed elevated HYAL1 levels in youths displaying high-BP and high-LVMI. CONCLUSIONS: The findings are compatible with a novel blood pressure-associated mechanism that may occur through impaired angiogenesis and extracellular matrix degradation through dysregulation of Vasohibin-1 and Hyaluronidase1 was identified as a possible mediator of CV-TOI in youth with high-BP and suggests strategies for ameliorating TOI in adult-onset primary hypertension.

3.
J Biol Chem ; : 107557, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-39002668

RESUMO

Glycosylphosphatidylinositol (GPI) anchor protein modification in Plasmodium species is well known and represents the principal form of glycosylation in these organisms. The structure and biosynthesis of GPI anchors of Plasmodium spp. has been primarily studied in the asexual blood stage of P. falciparum and is known to contain the typical conserved GPI structure of EtN-P-Man3GlcN-PI. Here, we have investigated the circumsporozoite protein (CSP) for the presence of a GPI-anchor. CSP is the major surface protein of Plasmodium sporozoites, the infective stage of the malaria parasite. While it is widely assumed that CSP is a GPI-anchored cell surface protein, compelling biochemical evidence for this supposition is absent. Here, we employed metabolic labeling and mass-spectrometry based approaches to confirm the presence of a GPI anchor in CSP. Biosynthetic radiolabeling of CSP with [3H]-palmitic acid and [3H]-ethanolamine, with the former being base-labile and therefore ester-linked, provided strong evidence for the presence of a GPI anchor on CSP, but these data alone were not definitive. To provide further evidence, immunoprecipitated CSP was analyzed for presence of myo-inositol (a characteristic component of GPI anchor) using strong acid hydrolysis and GC-MS for a highly sensitive and quantitative detection. The single ion monitoring (SIM) method for GC-MS analysis confirmed the presence of the myo-inositol component in CSP. Taken together, these data provide confidence that the long-assumed presence of a GPI anchor on this important parasite protein is correct.

4.
BMC Psychol ; 12(1): 373, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38956692

RESUMO

Despite widespread engagement in contemplative religious practices, comparatively little research has been conducted on their potential effects on well-being. Furthermore, few studies have focused on how an explicitly religious framing may impact the outcomes of such practices. In this online randomized controlled trial (N = 702), we tested the well-being effects of a contemplative prayer practice called Centering Prayer on self-identifying Christians. We compared 1) presenting the practice with an explicitly religious framing (experimental condition), 2) presenting the practice without an explicitly religious framing (active control), and 3) presenting simple instructions to reflect on the day, without any instructions regarding a meditation-like practice (passive control). After randomization into one of these three conditions, participants were asked to complete their assigned practice daily for 28 days. We hypothesized that the religious framing version of the practice would increase well-being over the active and passive control conditions. Well-being was assessed at three follow-up time points: one day, one week, and one month after the practice period. We found no group differences between the conditions on our primary outcome measure of well-being at one-week post-intervention. Each group increased in well-being from baseline to follow-up. We found significant group differences on acute measures of spiritual experience, the Mystical Experience Questionnaire (MEQ-30) and Daily Spiritual Experience Questionnaire (DSES). These results suggest that a religious framing may not enhance well-being effects but may alter spiritual outcomes related to contemplative practices.


Assuntos
Cristianismo , Estresse Psicológico , Humanos , Feminino , Masculino , Adulto , Estresse Psicológico/psicologia , Pessoa de Meia-Idade , Meditação/métodos , Meditação/psicologia , Religião e Psicologia , Adulto Jovem
5.
Sci Rep ; 14(1): 15673, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38977870

RESUMO

Low skeletal muscle index/density (SMI/SMD) is prevalent in cancer, adversely prognostic and associated with tumour stage and the systemic inflammatory response (SIR). Age and SMI/SMD has not been widely studied. The present study analyses the association between age and SMI/SMD after adjustment for other clinicopathological factors. Patients undergoing resectional surgery for TNM Stage I-III disease within the West of Scotland between 2011 and 2014 were identified. A single CT slice was obtained from each patients staging CT scan. SMI and SMD were stratified normal/abnormal. The SIR was stratified using Systemic Inflammatory Grade (SIG). When stratified by age (< 50/50s/60s/70s/80+), 39%/38%/48%/62%/74% and 27%/48%/64%/82%/92% of patients had a low SMI and SMD respectively (both p < 0.001). Older age (OR 1.47, p < 0.001), female sex (OR 1.32, p = 0.032), lower socioeconomic deprivation (OR 1.15, p = 0.004), higher ASA (OR 1.30, p = 0.019), emergency presentation (OR 1.82, p = 0.003), lower BMI (OR 0.67, p < 0.002) and higher SIG (OR 1.23, p < 0.001) were independently associated with low SMI. Older age (OR 2.28, p < 0.001), female sex (OR 1.38, p = 0.038), higher ASA (OR 1.92, p < 0.001), emergency presentation (OR 1.71, p = 0.023), and higher SIG (OR 1.37, p < 0.001) were independently associated with lower SMD. Tumour factors were not independently associated with either SMI/SMD. Age was a major factor associated with low SMI/SMD in patients with colon cancer. Therefore, in these patients it is likely that this represents largely constitutional body composition as opposed to being a disease mediated effect. Adjustment for age is required when considering the cancer mediated effect on SMI/SMD in patients with colon cancer.


Assuntos
Composição Corporal , Neoplasias do Colo , Inflamação , Estadiamento de Neoplasias , Tomografia Computadorizada por Raios X , Humanos , Masculino , Feminino , Neoplasias do Colo/patologia , Neoplasias do Colo/diagnóstico por imagem , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Fatores Etários , Inflamação/patologia , Músculo Esquelético/patologia , Músculo Esquelético/diagnóstico por imagem , Adulto
6.
J Biol Chem ; 300(8): 107500, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38944124

RESUMO

In eukaryotes, the D-enantiomer of arabinose (D-Ara) is an intermediate in the biosynthesis of D-erythroascorbate in yeast and fungi and in the biosynthesis of the nucleotide sugar GDP-α-D-arabinopyranose (GDP-D-Arap) and complex α-D-Arap-containing surface glycoconjugates in certain trypanosomatid parasites. Whereas the biosynthesis of D-Ara in prokaryotes is well understood, the route from D-glucose (D-Glc) to D-Ara in eukaryotes is unknown. In this paper, we study the conversion of D-Glc to D-Ara in the trypanosomatid Crithidia fasciculata using positionally labeled [13C]-D-Glc and [13C]-D-ribose ([13C]-D-Rib) precursors and a novel derivatization and gas chromatography-mass spectrometry procedure applied to a terminal metabolite, lipoarabinogalactan. These data implicate the both arms of pentose phosphate pathway and a likely role for D-ribulose-5-phosphate (D-Ru-5P) isomerization to D-Ara-5P. We tested all C. fasciculata putative sugar and polyol phosphate isomerase genes for their ability to complement a D-Ara-5P isomerase-deficient mutant of Escherichia coli and found that one, the glutamine fructose-6-phosphate aminotransferase (GFAT) of glucosamine biosynthesis, was able to rescue the E. coli mutant. We also found that GFAT genes of other trypanosomatid parasites, and those of yeast and human origin, could complement the E. coli mutant. Finally, we demonstrated biochemically that recombinant human GFAT can isomerize D-Ru-5P to D-Ara5P. From these data, we postulate a general eukaryotic pathway from D-Glc to D-Ara and discuss its possible significance. With respect to C. fasciculata, we propose that D-Ara is used not only for the synthesis of GDP-D-Arap and complex surface glycoconjugates but also in the synthesis of D-erythroascorbate.

7.
Chem Commun (Camb) ; 60(58): 7431-7434, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38938210

RESUMO

The 1967 attempt of structural analysis of the solid-state complex of caffeine and pyrogallol was a pioneering structural investigation in the supramolecular chemistry of caffeine, of what today would easily be considered an archetype of a model pharmaceutical cocrystal. Re-investigating this historically important system demonstrates that this long overlooked complex is most likely a tetrahydrate with a different structure and composition than initially proposed, and provides the crystal structure of the anhydrous cocrystal.


Assuntos
Cafeína , Pirogalol , Cafeína/química , Pirogalol/química , Pirogalol/análogos & derivados , Estrutura Molecular , Cristalização , Modelos Moleculares , Cristalografia por Raios X
8.
PLoS Pathog ; 20(6): e1012333, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38935804

RESUMO

The bloodstream form of Trypanosoma brucei expresses large poly-N-acetyllactosamine (pNAL) chains on complex N-glycans of a subset of glycoproteins. It has been hypothesised that pNAL may be required for receptor-mediated endocytosis. African trypanosomes contain a unique family of glycosyltransferases, the GT67 family. Two of these, TbGT10 and TbGT8, have been shown to be involved in pNAL biosynthesis in bloodstream form Trypanosoma brucei, raising the possibility that deleting both enzymes simultaneously might abolish pNAL biosynthesis and provide clues to pNAL function and/or essentiality. In this paper, we describe the creation of a TbGT10 null mutant containing a single TbGT8 allele that can be excised upon the addition of rapamycin and, from that, a TbGT10 and TbGT8 double null mutant. These mutants were analysed by lectin blotting, glycopeptide methylation linkage analysis and flow cytometry. The data show that the mutants are defective, but not abrogated, in pNAL synthesis, suggesting that other GT67 family members can compensate to some degree for loss of TbGT10 and TbGT8. Despite there being residual pNAL synthesis in these mutants, certain glycoproteins appear to be particularly affected. These include the lysosomal CBP1B serine carboxypeptidase, cell surface ESAG2 and the ESAG6 subunit of the essential parasite transferrin receptor (TfR). The pNAL deficient TfR in the mutants continued to function normally with respect to protein stability, transferrin binding, receptor mediated endocytosis of transferrin and subcellular localisation. Further the pNAL deficient mutants were as viable as wild type parasites in vitro and in in vivo mouse infection experiments. Although we were able to reproduce the inhibition of transferrin uptake with high concentrations of pNAL structural analogues (N-acetylchito-oligosaccharides), this effect disappeared at lower concentrations that still inhibited tomato lectin uptake, i.e., at concentrations able to outcompete lectin-pNAL binding. Based on these findings, we recommend revision of the pNAL-dependent receptor mediated endocytosis hypothesis.


Assuntos
Endocitose , Glicosiltransferases , Transferrina , Trypanosoma brucei brucei , Trypanosoma brucei brucei/metabolismo , Trypanosoma brucei brucei/genética , Animais , Endocitose/fisiologia , Camundongos , Transferrina/metabolismo , Glicosiltransferases/metabolismo , Glicosiltransferases/genética , Tripanossomíase Africana/parasitologia , Tripanossomíase Africana/metabolismo , Mutação , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Receptores da Transferrina/metabolismo , Receptores da Transferrina/genética , Polissacarídeos
9.
J Hazard Mater ; 474: 134552, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-38823105

RESUMO

Contamination of water bodies with heavy metals poses a significant threat to human health and the environment, requiring the development of effective treatment techniques. In this context, aluminosilicates emerge as promising sorbents due to their cost-effectiveness and natural abundance. This review provides a clear, in-depth, and comprehensive description of the structure, properties, and characteristics of aluminosilicates, supporting their application as adsorbents and highlighting their diversity and adaptability to different matrices and analytes. Furthermore, the functionalization of these materials is thoroughly addressed, detailing the techniques currently used, exposing the advantages and disadvantages of each approach, and establishing comparisons and evaluations of the performances of various functionalized aluminosilicates in the extraction of heavy metals in aqueous matrices. This work aims not only to comprehensively review numerous studies from recent years but also to identify trends in the study of such materials and inspire future research and applications in the field of contaminant removal using aluminosilicates.

10.
bioRxiv ; 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38826328

RESUMO

Glycosylphosphatidylinositol (GPI) anchor protein modification in Plasmodium species is well known and represents the principal form of glycosylation in these organisms. The structure and biosynthesis of GPI anchors of Plasmodium spp. has been primarily studied in the asexual blood stage of P. falciparum and is known to contain the typical conserved GPI structure of EtN-P-Man3GlcN-PI. Here, we have investigated the circumsporozoite protein (CSP) for the presence of a GPI-anchor. CSP is the major surface protein of Plasmodium sporozoites, the infective stage of the malaria parasite. While it is widely assumed that CSP is a GPI-anchored cell surface protein, compelling biochemical evidence for this supposition is absent. Here, we employed metabolic labeling and mass-spectrometry based approaches to confirm the presence of a GPI anchor in CSP. Biosynthetic radiolabeling of CSP with [ 3 H]-palmitic acid and [ 3 H]-ethanolamine, with the former being base-labile and therefore ester-linked, provided strong evidence for the presence of a GPI anchor on CSP, but these data alone were not definitive. To provide further evidence, immunoprecipitated CSP was analyzed for presence of myo -inositol (a characteristic component of GPI anchor) using strong acid hydrolysis and GC-MS for a highly sensitive and quantitative detection. The single ion monitoring (SIM) method for GC-MS analysis confirmed the presence of the myo -inositol component in CSP. Taken together, these data provide confidence that the long-assumed presence of a GPI anchor on this important parasite protein is correct.

11.
Ann Clin Biochem ; : 45632241261274, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38806176

RESUMO

BACKGROUND: Healthcare laboratory systems produce and capture a vast array of information, yet do not always report all of this to the national infrastructure within the United Kingdom. The global COVID-19 pandemic brought about a much greater need for detailed healthcare data, one such instance being laboratory testing data. The reporting of qualitative laboratory test results (e.g. positive, negative or indeterminate) provides a basic understanding of levels of seropositivity. However, to better understand and interpret seropositivity, how it is determined and other factors that affect its calculation (i.e. levels of antibodies), quantitative laboratory test data are needed. METHOD: 36 data attributes were collected from 3 NHS laboratories and 29 CO-CONNECT project partner organisations. These were assessed against the need for a minimum dataset to determine data attribute importance. An NHS laboratory feasibility study was undertaken to assess the minimum data standard, together with a literature review of national and international data standards and healthcare reports. RESULTS: A COVID serology minimum data standard (CSMDS) comprising 12 data attributes was created and verified by 3 NHS laboratories to allow national granular reporting of COVID serology results. To support this, a standardised set of vocabulary terms was developed to represent laboratory analyser systems and laboratory information management systems. CONCLUSIONS: This paper puts forward a minimum viable standard for COVID-19 serology data attributes to enhance its granularity and augment the national reporting of COVID-19 serology laboratory results, with implications for future pandemics.

12.
medRxiv ; 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38562855

RESUMO

Background: Hypertension in adolescence is associated with subclinical target organ injury (TOI). We aimed to determine whether different blood pressure (BP) thresholds were associated with increasing number of TOI markers in healthy adolescents. Methods: 244 participants (mean age 15.5±1.8 years, 60.1% male) were studied. Participants were divided based on both systolic clinic and ambulatory BP (ABP), into low- (<75 th percentile), mid- (75 th -90 th percentile) and high-risk (>90 th percentile) groups. TOI assessments included left ventricular mass, systolic and diastolic function, and vascular stiffness. The number of TOI markers for each participant was calculated. A multivariable general linear model was constructed to evaluate the association of different participant characteristics with higher numbers of TOI markers. Results: 47.5% of participants had at least one TOI marker: 31.2% had one, 11.9% two, 3.7% three, and 0.8% four. The number of TOI markers increased according to the BP risk groups: the percentage of participants with more than one TOI in the low-, mid-, and high groups based on clinic BP was 6.7%, 19.1%, and 21.8% (p=0.02), and based on ABP was 9.6%, 15.8%, and 32.2% (p<0.001). In a multivariable regression analysis, both clinic BP percentile and ambulatory SBP index were independently associated with the number of TOI markers. When both clinic and ABP were included in the model, only the ambulatory SBP index was significantly associated with the number of markers. Conclusion: High SBP, especially when assessed by ABPM, was associated with an increasing number of subclinical cardiovascular injury markers in adolescents.

13.
Horm Res Paediatr ; : 1-6, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38626741

RESUMO

INTRODUCTION: Ovarian Sertoli cell tumors represent a subset of sex cord stromal tumors and are exceedingly rare in prepubertal children. Here, we report a girl with vaginal bleeding due to a Sertoli cell tumor who was originally thought to have McCune-Albright syndrome (MAS). CASE PRESENTATION: A previously healthy girl presented at age 2 years 6 months with breast development and vaginal bleeding. On exam, she had Tanner 4 breasts, Tanner 1 pubic hair, estrogenized vaginal mucosa, and a café-au-lait macule. Laboratory studies revealed an elevated estradiol with suppressed gonadotropins and negative tumor markers. Her bone age was advanced by more than 3 years. Pelvic ultrasound (US) revealed an enlarged uterus and a slightly larger left compared to right ovary. She was started on tamoxifen for presumed MAS. A repeat pelvic US 1 month later showed a heterogenous mass in the left ovary which was subsequently resected. Pathology revealed a Sertoli cell tumor, lipid-rich variant. Germline sequencing revealed a pathogenic STK11 variant, diagnostic for Peutz-Jeghers syndrome (PJS). CONCLUSION: The findings in our patient were strikingly similar to those encountered in MAS. To our knowledge, our patient is the youngest ever reported to present with precocious puberty due to a Sertoli cell tumor in the setting of PJS.

14.
J Am Chem Soc ; 146(15): 10875-10888, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38579119

RESUMO

Two isomeric pentacene dimers, each linked by a diamantane spacer, have been synthesized. These dimers are designed to provide experimental evidence to support quantum mechanical calculations, which predict the substitution pattern on the carbon-rich diethynyldiamantane spacer to be decisive in controlling the interpentacene coupling. Intramolecular singlet fission (i-SF) serves as a probe for the existence and strength of the electronic coupling between the two pentacenes, with transient absorption spectroscopy as the method of choice to characterize i-SF. 4,9-Substitution of diamantane provides a pentacene dimer (4,9-dimer) in which the two chromophores are completely decoupled and that, following photoexcitation, deactivates to the ground state analogous to a monomeric pentacene chromophore. Conversely, 1,6-substitution provides a pentacene dimer (1,6-dimer) that exhibits sufficiently strong coupling to drive i-SF, resulting in correlated triplet M(T1T1) yields close to unity and free triplet (T1 + T1) yields of ca. 50%. Thus, the diamantane spacer effectively switches "on" or "off" the coupling between the chromophores, based on the substitution pattern. The binary control of diamantane contrasts other known molecular spacers designed only to modulate the coupling strength between two pentacenes.

15.
Res Sq ; 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38562753

RESUMO

Neuromodulation trials for PTSD have yielded mixed results, and the optimal neuroanatomical target remains unclear. We analyzed three datasets to study brain circuitry causally linked to PTSD in military Veterans. After penetrating traumatic brain injury (n=193), lesions that reduced probability of PTSD were preferentially connected to a circuit including the medial prefrontal cortex (mPFC), amygdala, and anterolateral temporal lobe (cross-validation p=0.01). In Veterans without lesions (n=180), PTSD was specifically associated with connectivity within this circuit (p<0.01). Connectivity change within this circuit correlated with PTSD improvement after transcranial magnetic stimulation (TMS) (n=20) (p<0.01), even though the circuit was not directly targeted. Finally, we directly targeted this circuit with fMRI-guided accelerated TMS, leading to rapid resolution of symptoms in a patient with severe lifelong PTSD. All results were independent of depression severity. This lesion-based PTSD circuit may serve as a neuromodulation target for Veterans with PTSD.

16.
Dalton Trans ; 53(16): 7206-7212, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38584458

RESUMO

The frustrated Lewis pair (FLP) adducts PB{ECl2} (PB = iPr2P(C6H4)BCy2; Cy = cyclohexyl; E = Si, Ge) were used to access a bis(alkynyl)-functionalized silylene and a germylene; the goal behind preparing these species was to obtain new unsaturated main group polymers [E(CCSiMe3)2]n upon heating. While the silylene adduct PB{Si(CCSiMe3)2} was stable up to 150 °C, the heavier element congener PB{Ge(CCSiMe3)2} underwent a complicated rearrangement process accompanied by Cy-group migration and Ge(II)-alkyne coordination. Density functional theory computations were performed to understand the mechanistic pathway for the unusual rearrangement of PB{Ge(CCSiMe3)2}.

17.
Phys Chem Chem Phys ; 26(13): 9940-9947, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38497243

RESUMO

The solid-state reaction of the active pharmaceutical ingredient theophylline with citric acid is a well-established example of a mechanochemical reaction, leading to a model pharmaceutical cocrystal. Here, classical force field molecular dynamics was employed to investigate the molecular mixing and structural distortion that take place on the mechanically driven indentation of a citric acid nanoparticle on a slab of crystalline theophylline. Through non-equilibrium molecular dynamics simulations, a 6 nm diameter nanoparticle of citric acid was introduced onto an open (001) surface of a theophylline crystal, varying both the angle of incidence of the nanoparticle between 15° and 90° and the indentation speed between 1 m s-1 and 16 m s-1. This theoretical study enabled the evaluation of how these two parameters promote molecular mixing and overall structural deformation upon the mechanical contraction of theophylline and citric acid, both of which are important parameters underlying mechanochemical cocrystallisation. The results show that the angle of incidence plays a key role in the molecular transfer ability between the two species and in the structural disruption of the initially spherical nanoparticles. Changing the indentation speed, however, did not lead to a discernible trend in molecular mixing, highlighting the importance of the incident angle in mechanochemical events in the context of supramolecular chemistry, such as the disruption of the crystal structure and molecular transfer between molecular crystals.

18.
J Neurosci ; 44(15)2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38423761

RESUMO

Music is a universal human attribute. The study of amusia, a neurologic music processing deficit, has increasingly elaborated our view on the neural organization of the musical brain. However, lesions causing amusia occur in multiple brain locations and often also cause aphasia, leaving the distinct neural networks for amusia unclear. Here, we utilized lesion network mapping to identify these networks. A systematic literature search was carried out to identify all published case reports of lesion-induced amusia. The reproducibility and specificity of the identified amusia network were then tested in an independent prospective cohort of 97 stroke patients (46 female and 51 male) with repeated structural brain imaging, specifically assessed for both music perception and language abilities. Lesion locations in the case reports were heterogeneous but connected to common brain regions, including bilateral temporoparietal and insular cortices, precentral gyrus, and cingulum. In the prospective cohort, lesions causing amusia mapped to a common brain network, centering on the right superior temporal cortex and clearly distinct from the network causally associated with aphasia. Lesion-induced longitudinal structural effects in the amusia circuit were confirmed as reduction of both gray and white matter volume, which correlated with the severity of amusia. We demonstrate that despite the heterogeneity of lesion locations disrupting music processing, there is a common brain network that is distinct from the language network. These results provide evidence for the distinct neural substrate of music processing, differentiating music-related functions from language, providing a testable target for noninvasive brain stimulation to treat amusia.

20.
Cortex ; 172: 109-113, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38271817

RESUMO

The Vietnam Head Injury Study has been curated by Dr Jordan Grafman since the 1980s in an effort to study patients with penetrating traumatic brain injuries suffered during the Vietnam War. Unlike many datasets of ischemic stroke lesions, the VHIS collected extraordinarily deep phenotyping and was able to sample lesion locations that are not constrained to typical vascular territories. For decades, this dataset has helped researchers draw causal links between neuroanatomical regions and neuropsychiatric symptoms. The value of the VHIS has only increased over time as techniques for analyzing the dataset have developed and evolved. Tools such as voxel lesion symptom mapping allowed one to relate symptoms to individual brain voxels. With the advent of the human connectome, tools such as lesion network mapping allow one to relate symptoms to connected brain networks by combining lesion datasets with new atlases of human brain connectivity. In a series of recent studies, lesion network mapping has been combined with the Vietnam Head Injury dataset to identify brain networks associated with spirituality, religiosity, consciousness, memory, emotion regulation, addiction, depression, and even transdiagnostic mental illness. These findings are enhancing our ability to make diagnoses, identify potential treatment targets for focal brain stimulation, and understand the human brain generally. Our techniques for studying brain lesions will continue to improve, as will our tools for modulating brain circuits. As these advances occur, the value of well characterized lesion datasets such as the Vietnam Head Injury Study will continue to grow. This study aims to review the history of the Vietnam Head Injury Study and contextualize its role in modern-day localization of neurological symptoms.


Assuntos
Lesões Encefálicas Traumáticas , Conectoma , Humanos , Vietnã , Encéfalo/patologia , Conectoma/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...