Stress from early life to adulthood: Is there a protective role of cognitive control?

Early life events can have long-lasting effects that may impact the quality of life into adulthood. The link between childhood adversities and adult mental and physical health is well documented, however, the underlying mechanisms remain poorly understood. Executive functions are assumed to be a key factor in successfully dealing with cognitive-emotional challenges thereby contributing to stress resilience and mental health across the lifespan. Here, we examined whether cognitive control moderates the link between early life adversity and depression. Data was available from a sample of 424 participants aged 20-70 years (Clinicaltrials.gov: NCT05155397). They performed in the Stroop task and behavior as well as frontal theta power were recorded. Negative childhood experiences were assessed with the Childhood Trauma Questionnaire (CTQ), chronic stress was measured with the Trier Inventory for Chronic Stress (TICS) and depression symptoms with Beck's Depression Inventory (BDI). The CTQ predicted symptoms of chronic stress and depression. Regression models pointed to the TICS as a crucial mediator in the relationship between CTQ and BDI. However, parameters of cognitive control demonstrated a rather weak effect as moderators. These results indicate that chronic stress is an important mediator linking childhood trauma to depression but suggest only a limited role for cognitive control.

Specific Birth Defects Following Antiseizure Medications Used By Pregnant Women With Epilepsy.

Background and Objectives: Previous research has been limited in the comprehensive study of associations between the use of individual antiseizure medications (ASMs) in pregnancy and specific groups of birth defects, and systematic reviews and meta-analyses on the topic are limited by pooled samples and study designs. This study investigated birth defects related to ASM use in pregnancy in children born to women with epilepsy in Sweden over 20 years. Methods: We used data from Swedish national registers to follow a cohort of 17,996 children born to women diagnosed with epilepsy any time before conception in Sweden from 1996 to 2016, following them through 2017. We examined maternal-reported use of the 4 most commonly reported ASMs: lamotrigine (n = 2,148, 11.9%), carbamazepine (n = 1,940, 10.8%), valproic acid (n = 1,043, 5.80%), and levetiracetam (n = 587, 3.26%). We identified birth defects using diagnoses recorded at the time of discharge from the hospital and inpatient and outpatient diagnoses recorded in the first year of life. Models were estimated in a stepped fashion: unadjusted, adjusted for covariates, among a subcohort born to women diagnosed 10 years before conception (n = 14,586), and restricted to monotherapy. Results: Valproic acid use in pregnancy had the strongest and most widespread associations with birth defects in children, with carbamazepine also having links to several birth defects, including respiratory system and genital organ defects. Lamotrigine use in pregnancy was associated with cleft lip/palate and chromosomal abnormalities. Levetiracetam was most often used with other ASMs and preliminarily associated with many birth defects. Discussion: Our findings support avoidance of valproic acid use in pregnancy whenever possible. Lamotrigine and carbamazepine may be safer alternatives. However, these medications were also associated with certain birth defects, including some not reported previously. We are among the first to examine the possible effects of levetiracetam use in pregnancy, though more research is needed to investigate this further.

The Janus kinase 1 is critical for pancreatic cancer initiation and progression.

Interleukin-6 (IL-6)-class inflammatory cytokines signal through the Janus tyrosine kinase (JAK)/signal transducer and activator of transcription (STAT) pathway and promote the development of pancreatic ductal adenocarcinoma (PDAC); however, the functions of specific intracellular signaling mediators in this process are less well defined. Using a ligand-controlled and pancreas-specific knockout in adult mice, we demonstrate in this study that JAK1 deficiency prevents the formation of KRASG12D-induced pancreatic tumors, and we establish that JAK1 is essential for the constitutive activation of STAT3, whose activation is a prominent characteristic of PDAC. We identify CCAAT/enhancer binding protein δ (C/EBPδ) as a biologically relevant downstream target of JAK1 signaling, which is upregulated in human PDAC. Reinstating the expression of C/EBPδ was sufficient to restore the growth of JAK1-deficient cancer cells as tumorspheres and in xenografted mice. Collectively, the findings of this study suggest that JAK1 executes important functions of inflammatory cytokines through C/EBPδ and may serve as a molecular target for PDAC prevention and treatment.

Australian consensus: Treatment goals for moderate to severe psoriasis in the era of targeted therapies - Considerations for paediatric patients.

BACKGROUND: Treatment goals have been established in Australia to facilitate the management of adults with moderate to severe psoriasis. The Australasian College of Dermatologists sought to determine if and how these adult treatment goals could be modified to accommodate the needs of paediatric and adolescent patients. METHODS: A modified Delphi approach was used. Comprehensive literature review and guideline evaluation resulted in the development of statements and other questions to establish current clinical practices. Two rounds of anonymous voting were undertaken, with a collaborative meeting held in between to discuss areas of discordance. Overall, consensus was defined as achievement of ≥75% agreement in the range 7-9 on a 9-point scale (1 strongly disagree; 9 strongly agree). RESULTS: Consensus was achieved on 23/29 statements in round 1 and 17/18 statements in round 2. There was a high level of concordance with treatment criteria in the adult setting. The limitations of applying assessment tools developed for use in adult patients to the paediatric setting were highlighted. Treatment targets in the paediatric setting should include objective metrics for disease severity and psychological impact on the patients and their family, and be based on validated, age-appropriate tools. CONCLUSION: While the assessment, classification and management of moderate to severe psoriasis in paediatric patients aligns with metrics established for adults, it is vital that nuances in the transition from childhood to adolescence be taken into account. Future research should focus on psoriasis severity assessment scales specific to the paediatric setting.

A Prototype Software Framework for Transferable Computational Health Economic Models and Its Early Application in Youth Mental Health.

We are developing an economic model to explore multiple topics in Australian youth mental health policy. To help make that model more readily transferable to other jurisdictions, we developed a software framework for authoring modular computational health economic models (CHEMs) (the software files that implement health economic models). We specified framework user requirements for: a simple programming syntax; a template CHEM module; tools for authoring new CHEM modules; search tools for finding existing CHEM modules; tools for supplying CHEM modules with data; reproducible analysis and reporting tools; and tools to help maintain a CHEM project website. We implemented the framework as six development version code libraries in the programming language R that integrate with online services for software development and research data archiving. We used the framework to author five development version R libraries of CHEM modules focussed on utility mapping in youth mental health. These modules provide tools for variable validation, dataset description, multi-attribute instrument scoring, construction of mapping models, reporting of mapping studies and making out of sample predictions. We assessed these CHEM module libraries as mostly meeting transparency, reusability and updatability criteria that we have previously developed, but requiring more detailed documentation and unit testing of individual modules. Our software framework has potential value as a prototype for future tools to support the development of transferable CHEMs.Code: Visit https://www.ready4-dev.com for more information about how to find, install and apply the prototype software framework.

Long-term Musculoskeletal Consequences of Chemotherapy in Pediatric Mice.

Thanks to recent progress in cancer research, most children treated for cancer survive into adulthood. Nevertheless, the long-term consequences of anticancer agents are understudied, especially in the pediatric population. We and others have shown that routinely administered chemotherapeutics drive musculoskeletal alterations, which contribute to increased treatment-related toxicity and long-term morbidity. Yet, the nature and scope of these enduring musculoskeletal defects following anticancer treatments and whether they can potentially impact growth and quality of life in young individuals remain to be elucidated. Here, we aimed at investigating the persistent musculoskeletal consequences of chemotherapy in young (pediatric) mice. Four-week-old male mice were administered a combination of 5-FU, leucovorin, irinotecan (a.k.a., Folfiri) or the vehicle for up to 5 wk. At time of sacrifice, skeletal muscle, bones, and other tissues were collected, processed, and stored for further analyses. In another set of experiments, chemotherapy-treated mice were monitored for up to 4 wk after cessation of treatment. Overall, the growth rate was significantly slower in the chemotherapy-treated animals, resulting in diminished lean and fat mass, as well as significantly smaller skeletal muscles. Interestingly, 4 wk after cessation of the treatment, the animals exposed to chemotherapy showed persistent musculoskeletal defects, including muscle innervation deficits and abnormal mitochondrial homeostasis. Altogether, our data support that anticancer treatments may lead to long-lasting musculoskeletal complications in actively growing pediatric mice and support the need for further studies to determine the mechanisms responsible for these complications, so that new therapies to prevent or diminish chemotherapy-related toxicities can be identified.

Nucleosome-binding by TP53, TP63, and TP73 is determined by the composition, accessibility, and helical orientation of their binding sites.

The p53 family of transcription factors plays key roles in driving development and combating cancer by regulating gene expression. TP53, TP63, and TP73-the three members of the p53 family-regulate gene expression by binding to their DNA binding sites, many of which are situated within nucleosomes. To thoroughly examine the nucleosome-binding abilities of the p53 family, we used Pioneer-seq, a technique that assesses a transcription factor's binding affinity to its DNA binding sites at all possible positions within the nucleosome core particle. Using Pioneer-seq, we analyzed the binding affinity of TP53, TP63, and TP73 to 10 p53-family binding sites across the nucleosome core particle. We found that the affinity of TP53, TP63, and TP73 for nucleosomes was largely determined by the positioning of p53-family binding sites within nucleosomes; p53-family members bind strongly to the more accessible edges of nucleosomes but weakly to the less accessible centers of nucleosomes. We also found that the DNA-helical orientation of p53-family binding sites within nucleosomal DNA impacted the nucleosome-binding affinity of p53-family members. The composition of their binding sites also impacted each p53-family member's nucleosome-binding affinities only when the binding site was located in an accessible location. Taken together, our results show that the accessibility, composition, and helical orientation of p53-family binding sites collectively determine the nucleosome-binding affinities of TP53, TP63, and TP73. These findings help explain the rules underlying p53-family-nucleosome binding and thus provide requisite insight into how we may better control gene-expression changes involved in development and tumor suppression.

An open label pilot trial of low-dose lithium for young people at ultra-high risk for psychosis.

AIM: Lithium, even at low doses, appears to offer neuroprotection against a wide variety of insults. In this controlled pilot, we examined the safety (i.e., side-effect profile) of lithium in a sample of young people identified at ultra-high risk (UHR) for psychosis. The secondary aim was to explore whether lithium provided a signal of clinical efficacy in reducing transition to psychosis compared with treatment as usual (TAU). METHODS: Young people attending the PACE clinic at Orygen, Melbourne, were prescribed a fixed dose (450 mg) of lithium (n = 25) or received TAU (n = 78). The primary outcome examined side-effects, with transition to psychosis, functioning and measures of psychopathology assessed as secondary outcomes. RESULTS: Participants in both groups were functionally compromised (lithium group GAF = 56.6; monitoring group GAF = 56.9). Side-effect assessment indicated that lithium was well-tolerated. 64% (n = 16) of participants in the lithium group were lithium-adherent to week 12. Few cases transitioned to psychosis across the study period; lithium group 4% (n = 1); monitoring group 7.7% (n = 6). There was no difference in time to transition to psychosis between the groups. No group differences were observed in other functioning and symptom domains, although all outcomes improved over time. CONCLUSIONS: With a side-effect profile either comparable to, or better than UHR antipsychotic trials, lithium might be explored for further research with UHR young people. A definitive larger trial is needed to determine the efficacy of lithium in this cohort.

A Case of Postoperative Biliary Leak in a Patient With Duplicated Cystic Ducts.

Duplicated cystic ducts are a rare congenital malformation with less than 20 reported cases before 2019. This malformation is important to identify to reduce the risk of intraoperative complications such as bile duct injuries that can increase postoperative morbidity and mortality. We present the case of a 62-year-old male with duplicated cystic ducts that were ligated during laparoscopic cholecystectomy and subsequently complicated by postoperative biloma formation. Treatment options for biliary leak include endoscopic retrograde cholangiopancreatography (ERCP) with stenting, percutaneous drainage, and duct embolization. Each carries the risk of complications such as infection, duct perforation, and stent/drain displacement. Roux-en-Y hepaticojejunostomy (RHYJ) tends to be the last resort when other minimally invasive procedures fail. It is imperative to identify postoperative complications related to cystic duct anomalies and the various treatment options available should these complications occur.

Nomenclature for psychosis risk in Japan: Survey results from high-risk individuals, caregivers, and mental health professionals.

BACKGROUND: Labeling terms for high-risk state for psychosis, such as 'ultra-high risk' (UHR), 'attenuated psychosis syndrome' (APS), and 'at-risk mental state' (ARMS), have been criticized for their potential to lead to stigma. Hence, mental health service users in Melbourne recently proposed new terms illustrating the at-risk concept ['pre-diagnosis stage' (PDS), 'potential of developing a mental illness' (PDMI), and 'disposition for developing a mental illness' (DDMI)]. We aimed at testing the suitability of these existing and new terms in the clinical settings of early psychiatric intervention in Japan. METHODS: At two centers of early intervention (Toyama and Tokyo), a questionnaire on the understanding and opinion of high-risk terminology was administered to 62 high-risk patients, 44 caregivers, and 64 clinicians. The questionnaire contained the existing and new terms, where the term ARMS was translated into two different Japanese terms ARMS-psychosis and ARMS-kokoro. Participants' opinion on the disclosure of high-risk status was also obtained. RESULTS: ARMS-kokoro was most preferred, least stigmatizing, and best explaining the patients' difficulties for all groups, while UHR and other terms including the Japanese word 'psychosis' (i.e., APS and ARMS-psychosis) were not preferred. New labeling terms were generally not well received. All groups preferred full disclosure of high-risk terms by the psychiatrist with or without the presence of family members. CONCLUSION: The term ARMS-kokoro was commonly accepted as a favorable labeling term for the high-risk state for psychosis in Japan. However, another translation ARMS-psychosis was considered stigmatizing, demonstrating the importance of appropriate translation of high-risk terminology into local languages.

Antegrade femoral lengthening and simultaneous hemiepiphysiodesis for congenital femoral deficiency.

Purpose: Congenital femoral deficiency is characterized by limb length discrepancy and genu valgum. Lengthening of the femur along its anatomic axis increases valgus alignment by medial knee translation. Pairing limb lengthening with simultaneous medial distal femoral hemiepiphysiodesis can simultaneously correct two limb deformities. Methods: All skeletally immature patients with congenital femoral deficiency who underwent antegrade femoral lengthening and concomitant guided growth over a 4-year period were reviewed. Length and alignment data were quantified during lengthening, consolidation, and for 1 year after guided growth implants were removed or the patient reached skeletal maturity. Digital simulation was performed for all lengthenings to assess the mechanical alignment that would have been achieved had lengthening been performed without medial distal femoral hemiepiphysiodesis. Results: Nine patients (five males, four females, mean age = 12.3 ± 1.9 years) underwent 10 antegrade intramedullary femoral lengthenings with simultaneous medial distal femoral hemiepiphysiodesis. All had improvement in valgus alignment (average improvement in mechanical axis deviation was 18 ± 11 mm, average change in limb alignment was 6 ± 5°). In simulated lengthenings without guided growth, all limbs would have experienced increased lateral mechanical axis deviation of 5 ± 3 mm. The hemiepiphysiodesis implant and lengthening device were explanted simultaneously in 7 of 10 lengthenings. Conclusion: Simultaneous medial distal femoral hemiepiphysiodesis with antegrade femoral lengthening for ongenital femoral deficiency can minimize the number of surgical episodes for the skeletally immature patient. The lengthening device and guided growth construct can be removed simultaneously in a majority of cases, saving children one or two additional surgical treatments.

Multidimensional analysis of cortical interneuron synaptic features reveals underlying synaptic heterogeneity.

Cortical interneurons represent a diverse set of neuronal subtypes characterized in part by their striking degree of synaptic specificity. However, little is known about the extent of synaptic diversity because of the lack of unbiased methods to extract synaptic features among interneuron subtypes. Here, we develop an approach to aggregate image features from fluorescent confocal images of interneuron synapses and their post-synaptic targets, in order to characterize the heterogeneity of synapses at fine scale. We started by training a model that recognizes pre- and post-synaptic compartments and then determines the target of each genetically-identified interneuron synapse in vitro and in vivo. Our model extracts hundreds of spatial and intensity features from each analyzed synapse, constructing a multidimensional data set, consisting of millions of synapses, which allowed us to perform an unsupervised analysis on this dataset, uncovering novel synaptic subgroups. The subgroups were spatially distributed in a highly structured manner that revealed the local underlying topology of the postsynaptic environment. Dendrite-targeting subgroups were clustered onto subdomains of the dendrite along the proximal to distal axis. Soma-targeting subgroups were enriched onto different postsynaptic cell types. We also find that the two main subclasses of interneurons, basket cells and somatostatin interneurons, utilize distinct strategies to enact inhibitory coverage. Thus, our analysis of multidimensional synaptic features establishes a conceptual framework for studying interneuron synaptic diversity.

A Pilot Feasibility Study on the Use of Dual-Joystick-Operated Ride-on Toys in Upper Extremity Rehabilitation for Children with Unilateral Cerebral Palsy.

Children with unilateral cerebral palsy (UCP) require task-oriented practice several hours per week to produce meaningful gains in affected upper extremity (UE) motor function. Clinicians find it challenging to provide services at the required intensity and sustain child engagement. This pilot study assessed the acceptance and utility of a child-friendly program using dual-joystick-operated ride-on toys incorporated into an intensive UE rehabilitation camp. Eleven children with UCP between four and 10 years received ride-on-toy navigation training for 20-30 min/day, five days/week, for three weeks as part of camp programming. We report session adherence and percent time children spent in task-appropriate attention/engagement across sessions. The overall effects of camp programming on children's motor function were assessed using the Shriner's Hospital Upper Extremity Evaluation (SHUEE) from pretest to posttest and using training-specific measures of bimanual UE use and navigational accuracy. Children showed excellent adherence and sustained task-appropriate engagement across sessions. The combined program led to improved navigational accuracy (p-values ≤ 0.007) as well as spontaneous affected UE use during bimanual activities outside the training context (p < 0.001). Our pilot study provides promising evidence for using modified, commercially available ride-on toys to incentivize rehabilitation and boost repetitive, task-oriented UE practice among children with UCP.

MRI in the Evaluation of Cryptogenic Stroke and Embolic Stroke of Undetermined Source.

Cryptogenic stroke refers to a stroke of undetermined etiology. It accounts for approximately one-fifth of ischemic strokes and has a higher prevalence in younger patients. Embolic stroke of undetermined source (ESUS) refers to a subgroup of patients with nonlacunar cryptogenic strokes in whom embolism is the suspected stroke mechanism. Under the classifications of cryptogenic stroke or ESUS, there is wide heterogeneity in possible stroke mechanisms. In the absence of a confirmed stroke etiology, there is no established treatment for secondary prevention of stroke in patients experiencing cryptogenic stroke or ESUS, despite several clinical trials, leaving physicians with a clinical dilemma. Both conventional and advanced MRI techniques are available in clinical practice to identify differentiating features and stroke patterns and to determine or infer the underlying etiologic cause, such as atherosclerotic plaques and cardiogenic or paradoxical embolism due to occult pelvic venous thrombi. The aim of this review is to highlight the diagnostic utility of various MRI techniques in patients with cryptogenic stroke or ESUS. Future trends in technological advancement for promoting the adoption of MRI in such a special clinical application are also discussed.

The Natural History of Splenic Artery Aneurysms: Factors That Predict Aneurysm Growth.

PURPOSE: To examine the natural history of splenic artery aneurysms (SAAs) at a single institution and assess the effect of patient factors and aneurysm characteristics on aneurysm growth. MATERIALS AND METHODS: This single-center retrospective study included patients with SAAs who underwent serial imaging over 30 years (1990-2020). Data regarding patient demographics and aneurysm characteristics were collected. The variables contributing to aneurysm growth were assessed using nonparametric tests for continuous variables and chi-square test for categorical variables. Multivariable linear regression was performed using aneurysm growth rate as a continuous dependent variable. RESULTS: A total of 132 patients were included in this study. The median maximum diameter of the SAAs was 15.8 mm (range, 4.0-50.0 mm). Growth over time was observed in 39% of the aneurysms, whereas the remaining 61% were stable in size. Of aneurysms that increased in size, the median aneurysm growth rate was 0.60 mm/y (range, 0.03-5.00 mm/y). Maximum aneurysm diameter of >2 cm and the presence of >50% mural thrombus were significant positive predictors for aneurysm growth (P = .020 and P = .022, respectively). Greater than 50% rim calcification was a significant negative predictor for aneurysm growth (P = .009) in multivariate analysis. CONCLUSIONS: A larger baseline SAA size, presence of mural thrombus, and lack of rim calcification are associated with increased aneurysm growth rate.

Socio-Demographic Factors Influencing Malaria Vaccine Acceptance for Under-Five Children in a Malaria-Endemic Region: A Community-Based Study in the Democratic Republic of Congo.

Two novel vaccines against malaria are proposed as a complementary control tool to prevent and reduce Plasmodium falciparum related disease and death in under-five children from moderate to high malaria transmission regions. The Democratic Republic of Congo (DRC) has committed to eradicate malaria by 2030, and significant efforts have been deployed to strengthen control and elimination measures. We aimed to understand factors influencing the malaria vaccine acceptability among the general population in eastern DRC. We conducted a survey among adult Congolese in Bukavu in March 2022. The questionnaire was adapted from the Behavioral and Social Drivers of vaccine uptake (BeSD) framework and was administered online and physically. Multivariate logistic regressions were built, and estimates were represented as adjusted odds ratios (aOR) and corresponding 95% confidence intervals (95%CI). Out of 1612 adults (median age: 39 years, 46.15% female) surveyed, only 7.26% were aware of the malaria vaccine. However, 46.53% expressed willingness to vaccinate themselves, and 52.60% were open to vaccinating their under-five children. Adjusting for confounding factors, non-student/non-healthcare worker professions (aOR = 0.58, 95%CI [0.42-0.78]) and middle-income status (aOR = 1.87, 95%CI [1.25-2.80]) were significantly associated with self-vaccination acceptance. Age played a role in under-five child vaccination acceptability, with 25 to over 64 years showing increased acceptability compared to the 18-24 age group. Additionally, non-student/non-healthcare worker professions (aOR = 1.88, 95%CI [1.37-2.59]), medium education levels (aOR = 2.64, 95%CI [1.29-5.79]), and residing in semi-rural areas (aOR = 1.63, 95%CI [1.27-2.10]) were predictors of under-five child vaccination acceptance. The acceptability of the malaria vaccine for self and for under-five children was suboptimal for effective malaria control in this community in the DRC. Our study constitutes a call for the Expanded Program on Immunization to closely work with various stakeholders to strengthen risk communication for community engagement prior to and during the introduction of this novel and lifesaving tool, malaria vaccination.

COVID-19 Vaccine Hesitancy and Associated Oral Cholera Vaccine Hesitancy in a Cholera-Endemic Country: A Community-Based Cross-Sectional Study in the Democratic Republic of Congo.

COVID-19 vaccine hesitancy and its enablers shape community uptake of non-covid vaccines such as the oral cholera vaccine (OCV) in the post-COVID-19 era. This study assessed the impact of COVID-19 vaccine hesitancy and its drivers on OCV hesitancy in a cholera-endemic region of the Democratic Republic of Congo. We conducted a community-based survey in Bukavu. The survey included demographics, intention to take OCV and COVID-19 vaccines, reasons for COVID-19 hesitancy, and thoughts and feelings about COVID-19 vaccines. Poisson regression analyses were performed. Of the 1708 respondents, 84.66% and 77.57% were hesitant to OCV alone and to both OCV and COVID-19, respectively. Hesitancy to COVID-19 vaccines rose OCV hesitancy by 12% (crude prevalence ratio, [cPR] = 1.12, 95%CI [1.03-1.21]). Independent predictors of OCV hesitancy were living in a semi-urban area (adjusted prevalence ratio [aPR] = 1.10, 95%CI [1.03-1.12]), religious refusal of vaccines (aPR = 1.06, 95%CI [1.02-1.12]), concerns about vaccine safety (aPR = 1.05, 95%CI [1.01-1.11]) and adverse effects (aPR = 1.06, 95%CI [1.01-1.12]), as well as poor vaccine literacy (aPR = 1.07, 95%CI [1.01-1.14]). Interestingly, the belief in COVID-19 vaccine effectiveness reduced OCV hesitancy by 24% (aPR = 0.76, 95%CI [0.62-0.93]). COVID-19 vaccine hesitancy and its drivers exhibited a significant domino effect on OCV uptake. Addressing vaccine hesitancy through community-based health literacy and trust-building interventions would likely improve the introduction of novel non-COVID-19 vaccines in the post-COVID-19 era.

Droplet microfluidics for time-resolved serial crystallography.

Serial crystallography requires large numbers of microcrystals and robust strategies to rapidly apply substrates to initiate reactions in time-resolved studies. Here, we report the use of droplet miniaturization for the controlled production of uniform crystals, providing an avenue for controlled substrate addition and synchronous reaction initiation. The approach was evaluated using two enzymatic systems, yielding 3 µm crystals of lysozyme and 2 µm crystals of Pdx1, an Arabidopsis enzyme involved in vitamin B6 biosynthesis. A seeding strategy was used to overcome the improbability of Pdx1 nucleation occurring with diminishing droplet volumes. Convection within droplets was exploited for rapid crystal mixing with ligands. Mixing times of <2 ms were achieved. Droplet microfluidics for crystal size engineering and rapid micromixing can be utilized to advance time-resolved serial crystallography.