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PubMed1975

Identification of the 120 mus phase in the decay of delayed fluorescence in spinach chloroplasts and subchloroplast particles as the intrinsic back reaction. The dependence of the level of this phase on the thylakoids internal pH.

After a 500 mus laser flash a 120 mus phase in the decay of delayed fluorescence is visible under a variety of circumstances in spinach chloroplasts and subchloroplast particles enriched in Photosystem II prepared by means of digitonin. The level of this phase is high in the case of inhibition of oxygen evolution at the donor side of Photosystem II. Comparison with the results of Babcock and Sauer (1975) Biochim. Bio-phys. Acta 376, 329-344, indicates that their EPR signal IIf which they suppose to be due to Z+, the oxidized first secondary donor of Photosystem II, is well correlated with a large amplitude of our 120 mus phase. We explain our 120 mus phase by the intrinsic back reaction of the excited reaction center in the presence of Z+, as predicted by Van Gorkom and Donze (1973) Photochem. Photobiol. 17, 333-342. The redox state of Z+ is dependent on the internal pH of the thylakoids. The results on the effect of pH in the mus region are compared with those obtained in the ms region.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗
PubMed2026

Venetoclax added to dose-adjusted EPOCH-R for newly diagnosed double-hit lymphomas: phase 2 results from ALLIANCE A051701, an open-label, randomised, controlled, phase 2-3 trial.

BACKGROUND: High-grade B-cell lymphoma with rearrangements of MYC and BCL2 and/or BCL6, known as double-hit lymphoma, is a highly aggressive malignancy with poor outcomes after standard chemoimmunotherapy. We aimed to study whether the addition of the BCL2-inhibitor venetoclax to chemoimmunotherapy in patients with double-hit lymphoma resulted in superior efficacy compared with chemotherapy alone. METHODS: ALLIANCE A051701 is an open-label, randomised, controlled, phase 2-3 trial in separate cohorts of patients with double-hit lymphoma and patients with double-expressor lymphoma. In this analysis, we report phase 2 results from the double-hit lymphoma cohort. Patients aged 18-80 years with newly diagnosed double-hit lymphoma and Eastern Cooperative Oncology Group (ECOG) performance status 0-2 were recruited from 41 hospitals and outpatient clinics in the USA. Patients were randomly assigned (1:1) to receive DA-EPOCH-R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab) either alone (DA-EPOCH-R group) or with venetoclax (DA-EPOCH-R plus venetoclax group) using permuted block randomisation schedule. All patients and investigators were aware of group assignment. DA-EPOCH-R was administered on a 21-day schedule for up to six total cycles. Venetoclax was given as 600 mg by mouth daily on days 4-8 of cycle 1 and on days 1-5 of cycles 2-6. The primary endpoint was progression-free survival in the modified intent-to-treat population inclusive of all eligible patients with centrally confirmed double-hit lymphoma. The safety analysis population consisted of all evaluable patients who received at least one dose of protocol treatment. This trial is registered with ClinicalTrials.gov (NCT03984448) and is closed to enrolment. FINDINGS: 36 patients were randomly assigned to the DA-EPOCH-R group and 37 to the DA-EPOCH-R plus venetoclax group between Oct 22, 2019, and Sept 18, 2020. Median age was 65 years (IQR 56-73) and baseline demographic factors were well balanced between groups, with 30 (45%) female and 36 (55%) male patients. Most patients (59 [89%]) were white, two (3%) were Asian, one (2%) was Black or African American, and four (6%) had unknown or unreported ethnicity. The majority of patients had MYC-BCL2 double-hit lymphoma (59 [89%] patients), advanced stage disease (57 [86%] patients), and high-intermediate/high-risk IPI score (42 [64%] patients). Median follow-up was 34·7 months (IQR 30·1-36·8). Median progression-free survival was 28·4 months (95% CI 5·2-not estimable) in the DA-EPOCH-R group (n=30) and 7·7 months (95% CI 4·7-NE) in the DA-EPOCH-R plus venetoclax group (n=36; hazard ratio [HR] 1·13, 95% CI 0·53-2·37; p=0·75). Deaths on treatment occurred in one (3%) patient in the DA-EPOCH-R group (due to dyspnoea; possibly related to treatment) and six (17%) patients in the DA-EPOCH-R plus venetoclax group (four due to sepsis [three at least possible related and one unrelated], two due to cardiac arrest [at least possibly related]), prompting early closure of the double-hit lymphoma cohort. The most common grade 3-4 non-haematological adverse event was febrile neutropenia, occurring in 15 (43%) of 35 patients in the DA-EPOCH-R plus venetoclax group and 11 (37%) of 30 patients in the DA-EPOCH-R group. The median overall survival has not been reached in either group. The 24-month overall survival estimates were 72% (95% CI 52-85) in the DA-EPOCH-R group compared with 52% (95% CI 33-68) in the DA-EPOCH-R plus venetoclax group (HR 2·49, 95% CI 1·03-6·04; p=0·038). INTERPRETATION: The addition of venetoclax to DA-EPOCH-R resulted in excess mortality, prompting early study closure. Robust accrual shows that prospective multicentre trials are feasible in double-hit lymphoma, and the outcomes in the DA-EPOCH-R group serve as a benchmark for future studies. FUNDING: National Cancer Institute of the National Institutes of Health.

Humans↗
PubMed1979

Combined reversed-phase and normal-phase high-performance liquid chromatography in the purification and identification of 7,12-dimethylbenz[a]anthracene metabolites.

A total of 37 compounds have been identified as rat liver microsomal metabolites of the potent carcinogen 7,12-dimethylbenz[a]anthracene and its hydroxymethyl derivatives 7-methyl-12-hydroxymethylbenz[a]anthracene, 7-hydroxymethyl-12-methylben[a]anthracene and 7,12-dihydroxymethylbenz[a]anthracene. The metabolites were characterized by: (i) retention times on reversed-phase (with a C18 column) and normal-phase (with a silica gel column) high-performance liquid chromatography (HPLC); (ii) ultraviolet absorption and fluorescence spectra; (iii) mass spectral analysis; (iv) optical activity; and (v) comparison of the physicochemical properties of the metabolites with those of some available synthetic standards. The 37 identified metabolites include four trans-3,4-dihydrodiols, four trans-5,6-dihydrodiols, four trans-8,9-dihydrodiols, four trans-10,11-dihydrodiols, two methyl carboxylic acids, two methyl aldehydes, two hydroxymethyl aldehydes, four 2-phenols, four 3-phenols, four 4-phenols and three hydroxymethyl derivatives. The trans configuration of the dihydrodiols was determined by their inability to form vicinal cisacetonides. Seven dihydrodiol metabolites were found to be optically active. Detailed physicochemical properties, such as ultraviolet absorption spectra, fluorescence spectra measured in methanol and in 0.1 N NaOH, major mass ions from mass spectral analysis and the retention times on two HPLC systems, are presented in support of the structural assignments.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1979

Novel 125I-labeled nortriptyline derivatives and their use in liquid-phase or magnetizable solid-phase second-antibody radioimmunoassays.

Nortriptyline derivatives prepared by reaction with fluorescein isothiocyanate or conjugation to N-acetyl-L-histidine were radioiodinated and the products purified with Sephadex LH-20 columns to obtain two novel nortriptyline radioligands. Antisera were raised in rabbits by immunization with nortriptyline conjugated to succinylated ovine albumin. By use of the iodinated fluorescein derivative we developed a liquid-phase second-antibody radioimmunoassay that gives results correlating closely (r = 0.98) with those by an established radioimmunoassay of similar specificity in the assay of apparent total amitriptyline and its metabolite nortriptyline in serum or plasma from patients being treated with these drugs. With the iodinated N-acetyl-L-histidine derivative we developed a magnetizable solid-phase second-antibody radioimmunoassay. The cross reactivities of amitriptyline and nortriptyline could be made equal by performing the assay at pH 9.0, which makes it possible to measure true total active drug concentrations in patients receiving amitriptyline.

Amitriptyline↗
PubMed2026

Risk-Benefit of Phase 2 Monotherapy Trials in Adult Solid Cancers: A Systematic Review and Meta-Analysis.

Phase 2 (and phase 1 dose expansion, which we label phase 2 for the purposes of this study) cancer trials are the first direct tests of a new drug's efficacy. Because efficacy evidence is lacking, the therapeutic status of drug administration during ethical review is uncertain. We compared the efficacy and safety of cancer monotherapies in phase 2&#xa0;with phase 3, where clinical equipoise underwrites a therapeutic status for drug administration. In this systematic review and meta-analysis, we searched Clinicaltrials.gov for phase 2 and 3 investigational monotherapy drug trials in six solid malignancies, with primary completion dates 2015-2020, inclusive. Two independent reviewers completed data extraction. Effects were estimated using an inverse-variance weighted random-effects model meta-analysis of proportions using the R package meta. We analyzed 130 phase 2 and 52 phase 3 trial arms, enrolling 6665 and 18,694 patients. The pooled objective response rate was 7% (95% CI 5%-11%) in phase 2 versus 24% in phase 3 (95% CI 17%-31%; p&#x2009;<&#x2009;0.0001). The median PFS and OS were shorter in phase 2 compared to phase 3 (3.23 vs. 5.43&#x2009;months, p&#x2009;<&#x2009;0.0001; 9.46 vs. 14.44&#x2009;months, p&#x2009;=&#x2009;0.0001). The pooled rate of drug-related grade 3-4 adverse events was 30% (95% CI 23%-37%) in phase 2 and 25% (95% CI 19%-32%) in phase 3. Monotherapies delivered in phase 2 cancer trials present diminished risk-benefit compared with phase 3 and align with historic estimates for phase 1. Though there may be exceptions, risks for drug administration in phase 2 should generally be justified by appeals to research rather than therapeutic value.

Humans↗
PubMed2026

A novel method for across-chromosome phasing without relative data.

MOTIVATION: Across-chromosome phasing identifies which haplotypes of different chromosomes come from the same parent. This differs from within-chromosome phasing, which uses linkage disequilibrium patterns to determine which alleles were co-inherited within each chromosome but does not match haplotypes across different chromosomes. While across-chromosome phasing can be conducted using genotypes from parents or close relatives, current methods perform poorly for samples of unrelated individuals. Here, we introduce a novel approach for across-chromosome phasing that employs a window-based SNP-similarity metric, eliminating the need for data from close relatives or detection of identical-by-descent haplotypes. RESULTS: Using UK Biobank offspring with both parents genotyped as a gold standard, we evaluated the performance of our method by phasing the offspring without using parental data. In genomic data with no within-chromosome phase errors, our algorithm achieved a mean across-chromosome phasing accuracy of 95%, with 53% of individuals phased perfectly. When data was pre-phased computationally using a standard within-chromosome phasing algorithm, mean accuracy for across-chromosome phasing dropped to 83.1%. Thus, our method is limited primarily by the accuracy of within-chromosome phasing accuracy and can approach near-perfect across-chromosome phasing accuracy as within-chromosome phasing accuracy improves. AVAILABILITY AND IMPLEMENTATION: The implementation was executed within a multi-node computational environment of University of Colorado Boulder Research Computing (Blanca Cluster: https://www.colorado.edu/rc/resources/blanca), employing parallelization techniques in the C programming language. The source code has been made publicly accessible online at https://github.com/emmanuelsapin/AcrossChromosomesPhasing, thereby facilitating reproducibility of the results for researchers with authorized access to the UK Biobank dataset.

Algorithms↗
PubMed2026

Chemoradiotherapy versus short-course radiotherapy for response-adapted organ preservation in early-stage and intermediate-stage rectal cancer (STAR-TREC): 12-month results of an international, multicentre, open-label, parallel-group, randomised, phase 2/3 trial.

BACKGROUND: Total mesorectal excision (TME) is the standard treatment for most early-stage and intermediate-stage rectal cancer but can cause substantial perioperative morbidity, functional impairment, and reduced quality of life. We assessed whether long-course chemoradiotherapy (LCCRT) or short-course radiotherapy (SCRT) could increase organ preservation and reduce surgery, toxicity, and quality-of-life harms without compromising oncological outcomes. METHODS: STAR-TREC is an international, multicentre, open-label, parallel-group, randomised, phase 2/3 trial in five European countries. Eligible patients were aged 16 years or older in the UK or aged 18 years or older elsewhere, had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, and rectal adenocarcinoma (&#x2264;40 mm staged as mrT1-T3bN0). In phase 2, participants were randomly assigned (1:1:1) to LCCRT-based organ preservation (LCCRT-OP; 50 Gy in 25 fractions plus oral capecitabine 825 mg/m2 twice daily), SCRT-based organ preservation (SCRT-OP; 25 Gy in five fractions), or primary TME. Phase 2 assessed feasibility, with recruitment at months 12 and 24 as the primary endpoint and feasibility thresholds of four or more and six or more randomisations per month, respectively. Phase 3 adopted a partially randomised patient-preference design, allowing participants to choose either organ preservation or TME. Participants that chose organ preservation were randomly assigned (1:1) to receive LCCRT-OP or SCRT-OP using centralised, computer-generated assignment, with stratification by country and MRI T category (&#x2264;T3a vs T3b) using minimisation. The phase 3 primary endpoint was organ-preservation 30 months after treatment initiation, defined as absence of TME, stoma, or local recurrence, which was assessed in the modified intention-to-treat population, which included participants in phase 2 and phase 3. After a planned interim analysis of unmasked phase 2 data, the trial steering committee and independent data monitoring committee recommended reporting a 12-month, modified intention-to-treat analysis of implementation outcomes for participants recruited before Aug 8, 2023. This study is registered with ISRCTN (14240288) and is closed. FINDINGS: Between June 14, 2017, and April 8, 2024, 503 participants were enrolled at 37 sites. Phase 2 enrolled 120 participants, with recruitment rates of three and six participants per month at months 12 and 24, respectively. Overall, 12-month TME-free survival was 60% (47 of 78 participants). After phase 3 recruitment ended, interim analysis of unmasked phase 2 data showed an early TME-free survival benefit with LCCRT versus SCRT (12-month median TME-free survival not reached [95% CI not reached-not reached] vs 7&#xb7;6 months [95% CI 6&#xb7;4-not reached]; hazard ratio [HR] 3&#xb7;7 [95% CI 1&#xb7;7-8&#xb7;0]; posterior probability of superiority >99&#xb7;5%). The trial steering committee and independent data monitoring committee therefore recommended expanded analysis of 426 participants recruited before Aug 8, 2023: 120 from phase 2 and 306 from phase 3. 17 participants withdrew before treatment, leaving 409 in the modified intention-to-treat population: 163 allocated to LCCRT, 168 to SCRT, and 78 to primary TME. 116 (28%) participants were female and 293 (72%) were male. Among participants who opted for organ preservation, 12-month TME-free survival was 78&#xb7;5% (95% CI 72&#xb7;4-85&#xb7;1) with LCCRT and 60&#xb7;6% (53&#xb7;6-68&#xb7;4) with SCRT (HR 1&#xb7;90 [95% CI 1&#xb7;29-2&#xb7;81]). The most common grade 3-4 serious adverse events were gastrointestinal disorders (four [2%] with LCCRT vs six [4%] with SCRT vs six [8%] with TME) and procedural complications (three [2%] with LCCRT vs five [3%] with SCRT vs five [6%] with TME). One participant allocated to primary TME died after an anastomotic leak. INTERPRETATION: These early results support a response-adapted organ-preservation approach, with LCCRT appearing more effective than SCRT at 12 months. Organ-preservation might also reduce treatment-related toxicity compared with primary TME. Longer follow-up is needed for the prespecified 30-month endpoint and definitive functional and oncological outcomes. FUNDING: Cancer Research UK, Stand Up to Cancer, Dutch Cancer Society, Danish Cancer Society, Kom Op Tegen Kanker, Cancerfonden, ALF Region Stockholm, RCC Region Stockholm.

Humans↗
PubMed2026

Ifebemtinib plus garsorasib in previously treated metastatic colorectal cancer with KRASG12C mutation: a multicentre, randomised, phase 1b/2 trial.

BACKGROUND: Ifebemtinib is a potent oral focal adhesion kinase inhibitor. Preclinical evidence supports combining ifebemtinib with the KRASG12C inhibitor garsorasib. This study aimed to evaluate this combination in KRASG12C-mutated solid tumours. METHODS: This multicentre, phase 1b/2 study had a phase 1b component to establish the recommended phase 2 dose and a phase 2 multitumour expansion component. In phase 1b, the safety and tolerability of ifebemtinib combined with garsorasib was assessed using a 3&#x2008;+&#x2008;3 design in KRASG12C-mutated solid tumours. No dose-limiting toxic effects were observed, and the recommended phase 2 dose was established as ifebemtinib 100 mg orally once daily plus garsorasib 600 mg orally twice daily. Here, we report the results of the cohort of previously treated KRASG12C-mutated metastatic colorectal cancer from phase 2 expansion. Eligible patients (aged &#x2265;18 years) who had histologically confirmed locally advanced or metastatic colorectal cancer harbouring the KRASG12C mutation, an Eastern Cooperative Oncology Group performance-status score of 0 or 1, and had disease progression after previous irinotecan-based or oxaliplatin-based combination therapy, were recruited from seven of nine participating tertiary hospitals in China. On the basis of the recommended phase 2 dose, phase 2 comprised a single-arm study to evaluate the safety and efficacy of ifebemtinib combined with garsorasib and an open-label, randomised study in which patients were randomly assigned (1:1) to receive ifebemtinib plus garsorasib or garsorasib alone, by use of centralised computer-generated block randomisation with no stratification. Investigators were masked to the block size. The primary efficacy endpoint of phase 2 was investigator-assessed objective response rate (Response Evaluation Criteria in Solid Tumours, version 1.1), assessed in the safety analysis set in the single-arm study and in all randomly assigned patients (intention-to-treat population) in the randomised study. At least six objective responses (safety analysis set) were required in the single-arm study to proceed to the randomised study. This study is registered with ClinicalTrials.gov, NCT06166836 and NCT05379946, and is active but not recruiting. FINDINGS: Between April 7, 2023 and Dec 13, 2024, 51 patients were enrolled in phase 2 (15 in the single-arm study and 36 in the randomised study). In the single-arm study, the median age was 53 years (IQR 39 to 63), nine (60%) patients were female, six (40%) were male, and all were Asian. In the randomised study, the median age was 51 years (IQR 42 to 59) in the combination group and 63 years (IQR 54 to 66) in the monotherapy group, 24 (67%) were female, 12 (33%) were male, and all patients were Asian. In the single-arm part, the confirmed objective response rate was 46&#xb7;7% (95% CI 21&#xb7;3 to 73&#xb7;4). Seven patients had partial responses, triggering progression to the randomised study. In the randomised study, the confirmed objective response rate was 38&#xb7;9% (95% CI 17&#xb7;3 to 64&#xb7;3) with the combination therapy versus 16&#xb7;7% (95% CI 3&#xb7;6 to 41&#xb7;4) with garsorasib alone (between-group difference 22&#xb7;2%, 95% CI -7&#xb7;7 to 49&#xb7;1; one-sided p=0&#xb7;068). In the single-arm study, grade 3 treatment-related adverse events occurred in four (27%) of 15 patients, and in the randomised study, grade 3 treatment-related adverse events occurred in six (33%) of 18 patients in the combination group and five (28%) of 18 in the garsorasib group. Grade 3 treatment-related adverse events occurring in at least two patients were diarrhoea (six [18%]), proteinuria (two [6%]), and intestinal obstruction (two [6%]) in patients treated with combination therapy (combined), and increased alanine aminotransferase and &#x3b3;-glutamyltransferase (two [11%] each) in patients treated with garsorasib alone. Serious adverse events occurred in ten (30%) patients in the combination group and in four (22%) patients in the monotherapy group. One patient in the garsorasib monotherapy group died due to the underlying malignancy within 30 days after completing study treatment, which was reported as a serious adverse event. The death was assessed by the investigators as not related to garsorasib. No grade 4 treatment-related adverse events or treatment-related deaths were reported across all cohorts. INTERPRETATION: The combination of ifebemtinib and garsorasib showed promising anticancer activity and manageable safety profile in previously treated patients with KRASG12C-mutated metastatic colorectal cancer. Although the improvement in response rate did not reach statistical significance in the randomised study, these findings support further evaluation of ifebemtinib plus garsorasib in this population. FUNDING: InxMed, InventisBio, National Natural Science Foundation of China, the Jian Bing Ling Yan + X Research and Development Program of Zhejiang Province, and the Zhejiang Province Medical and Health Science and Technology Plan Project.

Humans↗
PubMed2026

A multi-scale fusion model based on multi-phase contrast-enhanced CT for predicting pancreatic cancer resectability.

Purpose.Develop a multi-scale fusion model (MSFM) based on multi-phase contrast-enhanced computed tomography (CECT) to predict pancreatic cancer (PC) resectability, thereby assisting expert decision-making.Methods.This retrospective study enrolled 280 patients with PC from four institutions, which were randomly divided into a training cohort (202 patients) and an independent test cohort (78 patients). Three-phase CECT images (arterial, venous, and delayed phases) were used for modeling. The MSFM comprises two sub-networks: (1) a multi-phase fusion network for extracting cross-phase shared fusion features, (2) a phase-specific branch network for capturing phase-specific features; and a post-fusion strategy to generate the final predictive score by integrating the shared fusion features and three groups of phase-specific features. Additionally, a human-machine fusion deep learning model (HMfDL) was constructed by fusing the predictive score of the MSFM with expert assessments.Results.In the independent test, the MSFM achieved an AUC (area under the receiver operating characteristic curve) of 0.8385 (95% CI: 0.7521-0.9249), accuracy of 84.62%, sensitivity of 72.00%, and specificity of 90.57%. This performance outperformed single-phase models (AUC range: 0.7638-0.7781), two-phase models (AUC range: 0.7826-0.7864), and ten states-of-the-art classifiers (AUC range: 0.7404-0.7796). The HMfDL further improved the performance, reaching an AUC of 0.8626 (95% CI: 0.7853-0.9400), accuracy of 91.03%, sensitivity of 80.00%, and specificity of 96.23%. Notably, the HMfDL corrected 58.82% of misdiagnosis made by experts.Conclusions. The MSFM effectively fuses multi-phase CECT to enable highly accurate predictions of PC resectability, and provides valuable support for expert decision-making through HMfDL.

Humans↗
PubMed1978

The polymorphic phase behaviour of phosphatidylethanolamines of natural and synthetic origin. A 31P NMR study.

1. The polymorphic phase behaviour of aqueous dispersions of phosphatidylethanolamines isolated from human erythrocytes, hen egg yolk and Escherichia coli have been investigated employing 31P NMR techniques. All species exhibit well defined, reversible bilayer to hexagonal (H11) phase transitions as the temperature is increased. The temperatures at which these transition take place (10, 25--30 and 55--60 degrees C for erythrocyte, egg yolk and E. coli phosphatidylethanolamine, respectively) are sensitive to the fatty acid composition, occurring at a temperature up to 10 degrees C above the high temperature end of the hydrocarbon phase transition as detected by differential scanning calorimetry. In some cases the bilayer to hexagonal (H11) transitions may also be detected employing calorimetric techniques. 2. The addition of equimolar concentrations of cholesterol to these naturally occurring phosphatidylethanolamines does not dramatically affect the bilayer-hexagonal (H11) transition temperature, producing changes of up to 10 degrees C. 3. 18 : 1t/18 : 1t phosphatidylethanolamine undergoes the bilayer to hexagonal (H11) phase transition as the temperature is increased through the interval 50--55 degrees C. Alternatively, hydrated 12 : 0/12 : 0 phosphatidylethanolamine remains in the bilayer phase at temperatures up to 90 degrees C (50 degrees C above the hydrocarbon phase transition temperature). 4. The presence of 100 mM NaCl or 10 mM CaCl2 in aqueous dispersions of egg yolk phosphatidylethanolamine does not alter the temperature-dependent polymorphic phase behaviour significantly. However, at 40 degrees C, increasing the p2H above 8.0 results in progressive inhibition of the hexagonal (H11) phase and the appearance of a phase possibly of cubic structure at p2H 9.0. At p2H 10.0 the bilayer phase is preferred. 5. It is suggested that in biomembranes containing phosphatidylethanolamine as a majority species (such as that of E. coli) the fatty acid composition may primarily reflect the need to maintain bilayer structure. Alternatively, it is pointed out that in mammalian membranes such as that of the erythrocyte, phosphatidylethanolamine tends to destabilize bilayer structure. The resulting possibility that transitory non-bilayer lipid configurations may occur may be directly related to many important properties of biological membranes.

Animals↗
PubMed1978

Formation of liquid crystal and other non-fluid phases in emulsions containing non-ionic surfactants.

The relation between the phase distribution of components and the nature and properties of dispersions formed in a four-component system containing dodecane, water and two homogeneous non-ionic surfactants has been investigated by phase-rule techniques. Phase equilibrium diagrams for the four ternary systems were investigated and the phase boundaries for the various regions formed in these systems were defined by synthetic and analytical methods. In some of the ternary diagrams a narrow three-phase region occurs where 'gel' or liquid crystal as well as two isotropic liquid phases are present. Dispersions containing the gel phase were very stable. The four-component system has not been fully investigated due to the presence of extensive liquid crystal phases and three-phase regions. However, some distribution data for the quaternary system was obtained. In the presence of sufficient amounts of the short chain non-ionic surfactant C10H21(O.CH2.CH2)3OH, a three-liquid phase region occurs where multiple drops readily form.

Crystallization↗
PubMed2026

Cellular modifiers of TDP-43 phase transition and cytoplasmic aggregation.

RNA-binding protein TAR DNA-binding protein 43 (TDP-43) can form liquid-like nuclear assemblies whose phase behavior is thought to influence its aggregation propensity and neurotoxic activity. The mechanisms that govern the liquid-to-solid phase transition of TDP-43 remain poorly defined. Here, we combined chemical and genome-wide genetic screens to identify cellular factors that modulate the phase behavior of an RNA-binding-defective TDP-43 mutant. Our screens uncovered multiple cellular processes, including RNA splicing, protein translation, proteostasis imbalance, and nuclear export as TDP-43 phase regulators. We also developed a semi-permeabilized cell system that partially recapitulates the TDP-43 phase transition in vitro, and showed that nuclear export inhibition reshapes the nuclear environment to favor RNA-dependent liquid-liquid phase separation (LLPS) of TDP-43, which mitigates its aggregation. Nuclear export inhibition in a brain organoid model bearing an ALS-associated mutation reduces pathogenic phospho-TDP-43 accumulation. These findings identify multiple modulators of TDP-43 phase transitions in a sensitized model system and establish a framework for further dissecting the link between nuclear transport and TDP-43 phase dynamics.

DNA-Binding Proteins↗
PubMed1977

Depression of phase-transition temperature in a model cell membrane by local anesthetics.

Disordering, fluidizing and dilating effects of anesthetics upon cell membranes are well recognized. The fluidization can be precisely measured with phospholipid membranes. When phospholipids are dispersed in water, they form globules of bilayer structure. These model membranes undergo transition between crystalline (ordered and less fluid) and liquid crystalline (less ordered and fluid) phases according to the temperature, the degree of packing of each molecule, and the chemical environment. The phase transition occurs in a cooperative fashion and the turbidity of the dispersion changes abruptly, clear in liquid crystalline phase and turbid in crystalline phase. The present study was undertaken to quantitate the fluidizing effects of local anesthetics on dipalmitoyl lecithin (DPL) bilayer dispersion by measuring the turbidity change. Tetracaine, bupivacaine, lidocaine, and procaine were studied. They all depressed the phase-transition temperature. The binding of the drugs to the model membrane followed unsaturable kinetics, and the pH titration curve showed that only uncharged molecules were active. The freezing point depression was analyzed according to the Van't Hoff model. From this model, the partition coefficients of the uncharged molecules between DPL and water were estimated: lidocaine 76, procaine 159, bupivacaine 812, and tetracaine 1,405. The concentration of local anesthetics in the DPL phase needed to decrease the phase-transition temperature 1 degree C showed a constant value of 0.132 M. The concentration of local anesthetics in the DPL phase is a function of pH, partition coefficient, and volume ratio between the DPL and aqueous phases. The normalized values of the fluidizing action of these drugs at physiologic conditions correlated well with their nerve-blocking potencies. The present results indicate that the uncharged molecules fluidize the lecithin membrane by unsaturable nonspecific binding. The possible effect of the charged molecules upon the fluidity of natural membranes remains to be established.

Anesthetics, Local↗