The causal relationship between blood cell indices and 28-day mortality in sepsis: a retrospective study and bidirectional Mendelian randomization analysis.

BACKGROUND: Despite emerging evidence linking blood cell indices (BCIs) to sepsis mortality, the inconsistency of observational studies obscures the clarity of these associations. This study aims to clarify the causal influence of BCIs on 28-day mortality rates in sepsis patients. METHODS: Utilizing univariable and multivariable Mendelian randomization (MR) analyses, we examined the impact of BCIs on sepsis mortality by analyzing data from extensive genome-wide association studies. The inverse-variance weighted (IVW) method was our primary analytic tool, complemented by several robustness checks to mitigate pleiotropy, including weighted median, mode-based estimates, MR-Egger regression, and MR-PRESSO. Subsequently, we conducted a retrospective study to further explore the correlation between platelet indices and 28-day mortality of sepsis using real-world data. RESULTS: Our findings highlight a significant causal relationship between platelet distribution width (PDW) and 28-day mortality in sepsis, with the univariable Mendelian randomization approach yielding an odds ratio of 1.12 (95% CI, 1.06-1.26; P < 0.05). Multivariable analysis further substantiated PDW's robust association with mortality risk (OR 1.23; 95% CI, 1.03-1.48; P < 0.05). Conversely, our analysis did not uncover significant correlations between the genetic predispositions to other BCIs-including red blood cell count, erythrocyte distribution width, platelet count, mean platelet volume, white blood cell count, neutrophil count, neutrophil percentage, lymphocyte count, and lymphocyte percentage-and 28-day mortality in sepsis. Additionally, an inverse MR analysis did not establish a causal impact of 28-day mortality in sepsis on PDW (OR 1.00; 95% CI, 1.00-1.07; P = 0.29). Moreover, a similar result was observed in the retrospective study. CONCLUSIONS: The study underscores the independent causal role of PDW in predicting 28-day mortality in sepsis, suggesting its potential utility in early patient assessment, risk stratification, and tailoring of therapeutic interventions.

HCC subtypes based on the activity changes of immunologic and hallmark gene sets in tumor and nontumor tissues.

The prognostic role of adjacent nontumor tissue in hepatocellular carcinoma (HCC) patients is still not clear. The activity changes of immunologic and hallmark gene sets in adjacent nontumor tissues may substantially impact on prognosis by affecting proliferation of liver cells and colonization of circulating tumor cells after HCC treatment measures such as hepatectomy. We aimed to identify HCC subtypes and prognostic gene sets based on the activity changes of gene sets in tumor and nontumor tissues, to improve patient outcomes. We comprehensively revealed the activity changes of immunologic and hallmark gene sets in HCC and nontumor samples by gene set variation analysis (GSVA), and identified three clinically relevant subtypes of HCC by nonnegative matrix factorization method (NMF). Patients with subtype 1 had good overall survival, whereas those with subtype 2 and subtype 3 had poor prognosis. Patients with subtype 1 in the validation group also tended to live longer. We also identified three prognostic gene sets in tumor and four prognostic gene sets in nontumor by least absolute shrinkage and selection operator method (LASSO). Interestingly, functional enrichment analysis revealed that in nontumor tissues, genes from four gene sets correlated with immune reaction, cell adhesion, whereas in tumor tissue, genes from three gene sets closely correlated with cell cycle. Our results offer new insights on accurately evaluating prognosis-the important role of gene sets in both tumor and adjacent nontumor tissues, suggesting that when selecting for HCC treatment modality, changes in tumor and nontumor tissues should also be considered, especially after hepatectomy.

General Method of Manipulating Formation, Composition, and Morphology of Solid-Electrolyte Interphases for Stable Li-Alloy Anodes.

Li-alloy-based anode materials are very promising for breaking current energy limits of lithium-ion battery technologies. Unfortunately, these materials still suffer from poor solid-electrolyte interphase (SEI) stability, resulting in unsatisfied electrochemical performances. The typical SEI formation method, electrochemical decomposition of electrolytes onto the active material surface, lacks a deliberate control of the SEI functions and structures. Here we propose a general method of manipulating the formation process, chemical composition, and morphology of the SEI for Li-alloy anodes, using Si and Ge nanoparticle anodes as the platform. The SEI was fabricated through a covalent anchoring of multiple functional components onto the active material surface, followed by electrochemical decomposition of the functional components and conventional electrolyte. Click reaction, serving as the covalent anchoring approach, allows an accurate control of the SEI composition and structure at the molecular level through tuning the chemical structure and amount of variety of functional components and provides an intimate contact between the SEI and the Li-alloy material surface contributed by the covalent bonding. The optimized Si nanoparticle SEI, functionalized by a unique combination of diverse components and containing a high concentration of organic components attributed to the preanchored functional components, presented a stable composition and durable morphology during cycling and led to an improved first cycle efficiency of Si nanoparticle anodes and its long cycle life in a full cell. This general method displays potential benefits to construct stable SEIs for other Li-alloy anodes.

Functional Organosulfide Electrolyte Promotes an Alternate Reaction Pathway to Achieve High Performance in Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have recently received great attention because they promise to provide energy density far beyond current lithium ion batteries. Typically, Li-S batteries operate by conversion of sulfur to reversibly form different soluble lithium polysulfide intermediates and insoluble lithium sulfides through multistep redox reactions. Herein, we report a functional electrolyte system incorporating dimethyl disulfide as a co-solvent that enables a new electrochemical reduction pathway for sulfur cathodes. This pathway uses soluble dimethyl polysulfides and lithium organosulfides as intermediates and products, which can boost cell capacity and lead to improved discharge-charge reversibility and cycling performance of sulfur cathodes. This electrolyte system can potentially enable Li-S batteries to achieve high energy density.

Strong lithium polysulfide chemisorption on electroactive sites of nitrogen-doped carbon composites for high-performance lithium-sulfur battery cathodes.

Despite the high theoretical capacity of lithium-sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g(-1) after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm(-2)) with a high sulfur loading of approximately 5 mg cm(-2), which is ideal for practical applications of the lithium-sulfur batteries.

Successful treatment of severe hepatic impairment in erythropoietic protoporphyria: A case report and review of literature.

BACKGROUND: Erythropoietic protoporphyria (EPP) is a rare genetic disorder stemming from ferrochelatase gene mutations, which leads to abnormal accumulation of protoporphyrin IX primarily in erythrocytes, skin, bone marrow and liver. Although porphyria-related severe liver damage is rare, its consequences can be severe with limited treatment options. CASE SUMMARY: This case study highlights a successful intervention for a 35-year-old male with EPP-related liver impairment, employing a combination of red blood cell (RBC) exchange and therapeutic plasma exchange (TPE). The patient experienced significant symptom relief and a decrease in bilirubin levels following multiple PE sessions and an RBC exchange. CONCLUSION: The findings suggest that this combined approach holds promise for managing severe hepatic impairment in EPP.

Incidence and Outcomes of Brucella Endocarditis in a High-Prevalence Area: A Single-Center Study.

OBJECTIVE: To analyze the clinical characteristics of Brucella endocarditis (BE) and observe the factors related to death to provide guidance for clinical treatment. METHODS: This study examined all patients with BE admitted to The First People's Hospital of Kashi Prefecture between January 2017 and November 2023. Clinical characteristics and follow-up outcomes were collected for analysis. RESULTS: This study revealed 774 cases of brucellosis and 14 cases of BE, with an overall incidence rate of 1.88%. Most of the patients were male (71.43%) and lived in areas where brucellosis is common. Patients ranged in age from 26 to 68 years. Common symptoms reported among patients included chest tightness and fatigue, and a significant portion also presented with congestive heart failure. Most patients exhibited normal white blood cell counts (WBC) but had elevated levels of C-reactive protein (CRP). Transthoracic ultrasound (TTE) revealed cardiac valve vegetation in all patients, along with positive blood cultures. Six patients (42.86%) completed heart surgery, and ten (71.43%) completed anti-infection treatment. Six patients died, five of whom did not undergo surgery. The other patient with Marfan syndrome died after surgery. Sex, WBC count, neutrophil (NEUT) and total bilirubin (TBIL) were significant factors associated with regression in BE patients (P < 0.05) according to univariate analysis. CONCLUSIONS: Patients with BE in Kashi have a severe clinical presentation at diagnosis, but early detection with improved cardiac ultrasound and aggressive treatment can improve the prognosis.

Prognostic value of neutrophil-to-lymphocyte ratio in end-stage liver disease: A meta-analysis.

BACKGROUND: The neutrophil-to-lymphocyte ratio (NLR) is commonly utilized as a prognostic indicator in end-stage liver disease (ESLD), encompassing conditions like liver failure and decompensated cirrhosis. Nevertheless, some studies have contested the prognostic value of NLR in ESLD. AIM: To investigate the ability of NLR to predict ESLD. METHODS: Databases, such as Embase, PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Weipu, and Wanfang, were comprehensively searched to identify studies published before October 2022 assessing the prognostic ability of NLR to predict mortality in patients with ESLD. Effect sizes were calculated using comprehensive meta-analysis software and SATAT 15.1. RESULTS: A total of thirty studies involving patients with end-stage liver disease (ESLD) were included in the evaluation. Among the pooled results of eight studies, it was observed that the Neutrophil-to-Lymphocyte Ratio (NLR) was significantly higher in non-survivors compared to survivors (random-effects model: standardized mean difference = 1.02, 95% confidence interval = 0.67-1.37). Additionally, twenty-seven studies examined the associations between NLR and mortality in ESLD patients, reporting either hazard ratios (HR) or odds ratios (OR). The combined findings indicated a link between NLR and ESLD mortality (random-effects model; univariate HR = 1.07, 95%CI = 1.05-1.09; multivariate HR = 1.07, 95%CI = 1.07-1.09; univariate OR = 1.29, 95%CI = 1.18-1.39; multivariate OR = 1.29, 95%CI = 1.09-1.49). Furthermore, subgroup and meta-regression analyses revealed regional variations in the impact of NLR on ESLD mortality, with Asian studies demonstrating a more pronounced effect. CONCLUSION: Increased NLR in patients with ESLD is associated with a higher risk of mortality, particularly in Asian patients. NLR is a useful prognostic biomarker in patients with ESLD.

Clinical and Genetic Characteristics of Alagille Syndrome in Adults.

Background and Aims: Alagille syndrome (AGS) is an autosomal dominant multisystem disorder caused by mutations in the JAG1 and NOTCH2 genes. AGS has been rarely reported in adult patients, mainly because its characteristics in adults are subtle. The study aimed to improve the understanding of adult AGS by a descriptive case series. Methods: Eight adults diagnosed with AGS at our hospital between June 2016 and June 2019 were included in the study. Clinical data, biochemical results, imaging results, liver histopathology, and genetic testing were analyzed. Results: Three female and five male patients with a median age of 24.5 years at the time of diagnosis were included in the analysis. The clinical manifestations were adult-onset (62.5%, 5/8), cholestasis (50%, 4/8), butterfly vertebrae (62.5%, 5/8), systolic murmurs (12.5%, 1/8), typical facies (12.5%, 1/8), posterior embryotoxon, and renal abnormalities (0/8). Genetic sequencing showed that all patients had mutations, with four occurring in the JAG1 gene and four in the NOTCH2 gene. Six were substitution mutations, one was a deletion mutation, and one was a splicing mutation. Five had been previously reported; but the others, one JAG1 mutation and two NOTCH2 mutations were unique and are reported here for the first time. Conclusions: The clinical manifestations highlighted by the current diagnostic criteria for most adults with AGS are atypical. Those who do not meet the criteria but are highly suspicious of having AGS need further evaluation, especially genetic testing.

Silicon core-hollow carbon shell nanocomposites with tunable buffer voids for high capacity anodes of lithium-ion batteries.

Silicon core-hollow carbon shell nanocomposites with controllable voids between silicon nanoparticles and hollow carbon shell were easily synthesized by a two-step coating method and exhibited different charge-discharge cyclability as anodes for lithium-ion batteries. The best capacity retention can be achieved with a void/Si volume ratio of approx. 3 due to its appropriate volume change tolerance and maintenance of good electrical contacts.

Safety and efficacy of Thymosin α1 in the treatment of hepatitis B virus-related acute-on-chronic liver failure: a randomized controlled trial.

BACKGROUND/PURPOSE OF THE STUDY: Mortality from hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF) is high. Severe infection is the most important complication that affects the outcomes of ACLF patients. Thymosin α1 (Tα1) can improve immune imbalance and this study aimed to investigate the safety and efficacy of Tα1 treatment for HBV-related ACLF. METHODS: From 2017 to 2019, 120 patients with HBV-related ACLF were enrolled in this open-label, randomized, and controlled clinical trial (ClinicalTrial ID: NCT03082885). The control group (N = 58) was treated with standard medical therapy (SMT) only. The experimental group (N = 56) was subcutaneously injected with 1.6 mg of Tα1 once a day for the first week and then twice a week from week 2 to week 12. RESULTS: The 90-day cumulated liver transplantation free survival rate of the Tα1 group was 75.0% (95% confidence interval 63.2-86.8%) versus 53.4% (95% confidence interval 39.7-67.1%) for the SMT group (p = 0.030). No significant difference was found in the survival using competitive risk analysis. The incidences of new infection and hepatic encephalopathy in the Tα1 group were much lower than those in the SMT group (32.1% vs 58.6%, p = 0.005; 8.9% vs 24.1%, p = 0.029, respectively). Mortality from severe infection in the SMT group was higher than in the Tα1 group (24.1% vs 8.9%, p = 0.029). CONCLUSION: Tα1 is safe for patients with HBV-related ACLF and significantly improves the 90-day liver transplantation-free survival rate. There may be a subgroup which may benefit from Tα1 therapy by the mechanism of preventing infection.

Residual ß-Cell Function in Type 1 Diabetes Followed for 2 Years after 3C Study.

OBJECTIVE: To investigate the natural history and related factors of the pancreatic ß-cell function in Chinese type 1 diabetic patients from 3C study Shantou center. METHOD: Stimulated C-peptide levels from follow-up data of 201 individuals in 3C study Shantou subgroup starting in 2012 were used. Residual ß-cell function was defined as stimulated C - peptide level ≥ 0.2 pmol/mL, on the basis of cut-points derived from the Diabetes Control and Complications Trial (DCCT). RESULTS: 36.8% of patients had residual ß-cell function, and the percentage was 68.2% in newly diagnosed diabetic patients. COX regression analysis indicated that the age of diagnosis, HbA1C level, and duration were independent factors of residual ß-cell function in individuals with ≤5 years duration, but in those with duration ≥5 years, only the age of diagnosis was a predictor. The pancreatic ß-cell function mainly declined in the first 5 years of the duration, and the rate of decline was correlated negatively with the duration and age of diagnosis. Receiver operating characteristic (ROC) analysis indicated that the cut-off point of stimulated C-peptide was 0.615 pmol/mL in patients with <5 years duration to have 7% HbA1c. CONCLUSION: Age at diagnosis was the strongest predictor for residual C-peptide. There was a more rapid decline of stimulated C-peptide in duration ≤5 years and younger patients. Therefore, intervention therapies of ß-cells should start from the early stage, and the recommended target goal of stimulated C-peptide is 0.615 pmol/mL or above.

Corrigendum to "Residual ß-Cell Function in Type 1 Diabetes Followed for 2 Years after 3C Study".

[This corrects the article DOI: 10.1155/2021/9946874.].

Unsupervised Clustering Reveals Distinct Subtypes of Biliary Atresia Based on Immune Cell Types and Gene Expression.

Background: Biliary atresia (BA) is a severe cholangiopathy of early infancy that destroys cholangiocytes, obstructs ductular pathways and if left untreated, culminates to liver cirrhosis. Mechanisms underlying the etiological heterogeneity remain elusive and few studies have attempted phenotyping BA. We applied machine learning to identify distinct subtypes of BA which correlate with the underlying pathogenesis. Methods: The BA microarray dataset GSE46995 was downloaded from the Gene Expression Omnibus (GEO) database. Unsupervised hierarchical cluster analysis was performed to identify BA subtypes. Then, functional enrichment analysis was applied and hub genes identified to explore molecular mechanisms associated with each subtype. An independent dataset GSE15235 was used for validation process. Results: Based on unsupervised cluster analysis, BA patients can be classified into three distinct subtypes: Autoimmune, Viral and Embryonic subtypes. Functional analysis of Subtype 1 correlated with Fc Gamma Receptor (FCGR) activation and hub gene FCGR2A, suggesting an autoimmune response targeting bile ducts. Subtype 2 was associated with immune receptor activity, cytokine receptor, signaling by interleukins, viral protein interaction, suggesting BA is associated with viral infection. Subtype 3 was associated with signaling and regulation of expression of Robo receptors and hub gene ITGB2, corresponding to embryonic BA. Moreover, Reactome pathway analysis showed Neutrophil degranulation pathway enrichment in all subtypes, suggesting it may result from an early insult that leads to biliary stasis. Conclusions: The classification of BA into different subtypes improves our current understanding of the underlying pathogenesis of BA and provides new insights for future studies.

A perspective of the relationship of serum HBV DNA and HBsAg apportioned by the same hepatic parenchyma cell volume with inflammation in the natural history of chronic hepatitis B.

BACKGROUND: This study aimed to investigate the dynamic changes of serum HBV DNA and hepatitis B surface antigen (HBsAg) titers apportioned by the same hepatic parenchyma cell volume (HPCV) at different liver histological inflammation grades in the natural history of chronic hepatitis B (CHB). METHODS: The serum HBV DNA and HBsAg titers were detected by real-time polymerase chain reaction and electrochemiluminescence, separately, in CHB patients without any treatment. The serum HBV DNA levels and HBsAg titers apportioned by the same HPCV were figured out based on sphere geometry theory. In addition, the differences of HBV DNA levels and HBsAg titers apportioned by the same HPCV in different liver inflammation grades were further assessed based on statistical analysis. RESULTS: There was no difference of serum HBV DNA levels or HBsAg titers before apportioned by the same HPCV in liver inflammation grades 1-4, but significant differences were observed after apportion in CHB patients (HBV DNA: P=0.101; HBsAg: P=0.211 & HBV DNA apportioned by HPCV: P<0.001; HBsAg apportioned by HPCV: P<0.001). No correlation was observed between HBV DNA levels and liver inflammation grades (r=0.083, P=0.186), or between HBsAg titers and liver inflammation grades (r=0.083, P=0.078). A significant correlation was observed between HBV DNA levels apportioned by HPCV and liver inflammation grades (r=0.249, P<0.001), and obvious correlation of HBsAg titers apportioned by HPCV and liver inflammation grades was also found in CHB patients (r=0.554, P<0.001). CONCLUSIONS: These results suggest that the levels of serum HBV DNA and HBsAg apportioned by the same HPCV are correlated with the severity of liver histological inflammation grade in the natural history of CHB.

Epidemiological and clinical characteristics of Dengue virus outbreaks in two regions of China, 2014 - 2015.

Dengue virus (DENV), a single-stranded RNA virus and Flaviviridae family member, is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. DENV causes dengue fever, which may progress to severe dengue. Hospital-based surveillance was performed in two Chinese regions, Guangzhou and Xishuangbanna, during the dengue epidemics in 2014 and 2015, respectively. Acute-phase serum was obtained from 133 patients with suspected dengue infections during the peak season for dengue cases. Viremia levels, virus sero-positivity, serotype distribution, infection type, clinical manifestations and virus phylogenetics were investigated. Of the 112 DENV-confirmed cases, 92(82.14%) were IgM antibody-positive for DENV, and 69(51.88%) were positive for DENV RNA. From these cases, 47(41.96%) were classified as primary infections, 39(34.82%) as secondary infections and 26 (23.21%) as undetermined infections. The viremia levels were negatively correlated with IgM presence, but had no relationship with the infection type. DENV-1 genotype V dominated in Guangzhou, whereas the DENV-2 Cosmopolitan genotype dominated in Xishuangbanna, where fewer DENV-1 genotype I cases occurred. DENV-2 is associated with severe dengue illness with more serious clinical issues. The strains isolated during 2014-2015 are closely related to the isolates obtained from other Chinese regions and to those isolated recently in Southeast Asian countries. Our results indicate that DENV is no longer an imported virus and is now endemic in China. An extensive seroepidemiological study of DENV and the implementation of vector control measures against it are now warranted in China.

Minimized Volume Expansion in Hierarchical Porous Silicon upon Lithiation.

Silicon (Si) remains one of the most promising anode materials for next-generation lithium-ion batteries (LIBs). The key challenge for Si anodes is the huge volume change during lithiation-delithiation cycles that leads to electrode pulverization and rapid capacity fading. Here, we report a hierarchical porous Si (hp-Si) with a tailored porous structure [tunable primary pores (20-200 nm) and secondary nanopores (∼3-10 nm)] that can effectively minimize the volume expansion. An in situ transmission electron microscopy (TEM) study revealed that the hp-Si material with the same porosity but larger primary pores can more effectively accommodate lithiation-induced volume expansion, giving rise to a much reduced apparent volume expansion on both material and electrode levels. Chemomechanical modeling revealed that because of the different relative stiffnesses of the lithiated and unlithiated Si phases, the primary pore size plays a key role in accommodating the volume expansion of lithiated Si. The higher structural stability of the hp-Si materials with larger primary pores also maintains the fast diffusion channels of the connective pores, giving rise to better power capability and capacity retention upon electrochemical cycling. Our findings point toward an optimized hp-Si material with minimal volume change during electrochemical cycling for next-generation LIBs.

High-Voltage Lithium-Metal Batteries Enabled by Localized High-Concentration Electrolytes.

Rechargeable lithium-metal batteries (LMBs) are regarded as the "holy grail" of energy-storage systems, but the electrolytes that are highly stable with both a lithium-metal anode and high-voltage cathodes still remain a great challenge. Here a novel "localized high-concentration electrolyte" (HCE; 1.2 m lithium bis(fluorosulfonyl)imide in a mixture of dimethyl carbonate/bis(2,2,2-trifluoroethyl) ether (1:2 by mol)) is reported that enables dendrite-free cycling of lithium-metal anodes with high Coulombic efficiency (99.5%) and excellent capacity retention (>80% after 700 cycles) of Li||LiNi1/3 Mn1/3 Co1/3 O2 batteries. Unlike the HCEs reported before, the electrolyte reported in this work exhibits low concentration, low cost, low viscosity, improved conductivity, and good wettability that make LMBs closer to practical applications. The fundamental concept of "localized HCEs" developed in this work can also be applied to other battery systems, sensors, supercapacitors, and other electrochemical systems.

Electrode Edge Effects and the Failure Mechanism of Lithium-Metal Batteries.

The very high specific capacity of Li metal makes it an ideal anode for high-energy batteries. However, Li dendrite growth and the formation of isolated (or "dead") Li during repeated Li plating/stripping processes leads to a low coulombic efficiency (CE). In this work, we discovered, for the first time, that electrode edge effects play an important role in the failure of Li-metal batteries. The dead Li formed on the edge of Cu substrate was systematically investigated through SEM, energy-dispersive X-ray (EDX) spectroscopy, and 2D X-ray photoelectron spectroscopy (XPS). To minimize the Li loss at the edge of the Cu exposed to pressure-free space, a modified Li∥Cu cell configuration with a Cu electrode smaller than Li metal is preferred. It was clearly demonstrated that using an electrode configuration with a minimal open space or pressure-free space across electrodes can reduce accumulation of dead Li during cycling and increase Li CE. This phenomenon was also verified in Li-metal batteries (Li∥LiNi1/3 Mn1/3 Co1/3 O2 ) and should be considered in the design of practical Li-metal batteries.

Differential effects of Cbl isoforms on Egfr signaling in Drosophila.

The Cbl family of proteins downregulate epidermal growth factor receptor (Egfr) signaling via receptor internalization and destruction. These proteins contain two functional domains, a RING finger domain with E3 ligase activity, and a proline rich domain mediating the formation of protein complexes. The Drosophila cbl gene encodes two isoforms, D-CblS and D-CblL. While both contain a RING finger domain, the proline rich domain is absent from D-CblS. We demonstrate that expression of either isoform is sufficient to rescue both the lethality of a D-cbl null mutant and the adult phenotypes characteristic of Egfr hyperactivation, suggesting that both isoforms downregulate Egfr signaling. Interestingly, targeted overexpression of D-CblL, but not D-CblS, results in phenotypes characteristic of reduced Egfr signaling and suppresses the effect of constitutive Egfr activation. The level of D-CblL was significantly correlated with the phenotypic severity of reduced Egfr signaling, suggesting that D-CblL controls the efficiency of downregulation of Egfr signaling. Furthermore, reduced dynamin function suppresses the effects of D-CblL overexpression in follicle cells, suggesting that D-CblL promotes internalization of activated receptors. D-CblL is detected in a punctate cytoplasmic pattern, whereas D-CblS is mainly localized at the follicle cell cortex. Therefore, D-CblS and D-CblL may downregulate Egfr through distinct mechanisms.