Search

BackgroundThe coronavirus pandemic has caused a worldwide health crisis. Bariatric patients require extensive pre- and post-operative follow-up, which may be less feasible during public health social distancing mandates. We assessed the impact of the pandemic on the behaviors and weight loss outcomes of our pre- and post-operative bariatric patients.MethodsA retrospective review of a prospectively maintained database identified patients who underwent either sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) at a single institution between March 2018 and May 2020. A cohort undergoing surgery within 12months before the pandemic as well as a cohort undergoing a medically supervised diet prior to surgery was surveyed regarding pre- and post-COVID-19 lifestyle habits. Excess weight loss (EWL) outcomes from a group of pre-COVID surgical patients were compared to that of a group of post-COVID surgical patients. Primary outcome was whether the lockdown changed 1-year weight loss outcomes. Secondary outcome was whether patient lifestyle behaviors were changed during the pandemic.ResultsThere was no difference in 1-year EWL between pre- and post-COVID SG patients (51.7% versus 55.9%, p = 0.35), or between pre- and post-COVID RYGB patients (88.9% versus 80.4%, p = 0.42). Pre-stay-at-home order, 91.8% endorsed physical activity compared to 80.3% post-stay-at-home order (p = 0.0025). Mean physical activity decreased from 4.2h/week to 2.7h/week after the stay-at-home order (p

Obesity is variably associated with treatment response in biologic-treated patients with inflammatory bowel diseases (IBD). We evaluated the association between obesity and risk of hospitalization, surgery, or serious infections in patients with IBD in new users of biologic agents in a large, multicenter, electronic health record (EHR)-based cohort (CA-IBD).We created an EHR-based cohort of adult patients with IBD who were new users of biologic agents (tumor necrosis factor [TNF-α] antagonists, ustekinumab, and vedolizumab) between January 1, 2010, and June 30, 2017, from 5 health systems in California. Patients were classified as those with normal body mass index (BMI), overweight, or obese based on the World Health Organization classification. We compared the risk of all-cause hospitalization, IBD-related surgery, or serious infections among patients with obesity vs those overweight vs those with normal BMI, using Cox proportional hazard analyses, adjusting for baseline demographic, disease, and treatment characteristics.Of 3,038 biologic-treated patients with IBD (69% with Crohn's disease and 76% on TNF-α antagonists), 28.2% (n = 858) were overweight, and 13.7% (n = 416) were obese. On a follow-up after biologic initiation, obesity was not associated with an increased risk of hospitalization (adjusted hazard ratio [aHR] vs normal BMI, 0.90; [95% confidence interval, 0.72-1.13]); IBD-related surgery (aHR, 0.62 [0.31-1.22]); or serious infection (aHR, 1.11 [0.73-1.71]). Similar results were observed on stratified analysis by disease phenotype (Crohn's disease vs ulcerative colitis) and index biologic therapy (TNF-α antagonists vs non-TNF-α antagonists).In a multicenter, EHR-based cohort of biologic-treated patients with IBD, obesity was not associated with hospitalization, surgery, or serious infections. Further studies examining the effect of visceral obesity on patient-reported and endoscopic outcomes are needed.

Genetic variants are vital in informing clinical phenotypes, aiding physical diagnosis, guiding genetic counseling, understanding the molecular basis of disease, and potentially stimulating drug development. Here we describe two families with an ultrarare ACVR1 gain-of-function pathogenic variant (codon 375, Arginine > Proline; ACVR1R375P ) responsible for a mild nonclassic fibrodysplasia ossificans progressiva (FOP) phenotype. Both families include people with the ultrarare ACVR1R375P variant who exhibit features of FOP while other individuals currently do not express any clinical signs of FOP. Thus, the mild ACVR1R375P variant greatly expands the scope and understanding of this rare disorder.

The rising prevalence of insulin resistance (IR), metabolic syndrome, and type 2 diabetes are associated with increases in abdominal mesenteric fat. Adipocytes are sensitive to low temperatures, making cryolipolysis of mesenteric fat an attractive treatment modality to potentially reduce IR.We aimed to determine whether (1) cryolipolysis is safe in reducing the volume of the mesenteric fat and (2) reduction in mesenteric fat volume reduces indices of IR and glycemic dysfunction.Indiana University School of Medicine.A novel cooling device and method delivered cryolipolysis in a controlled manner to avoid tissue ablative temperatures. Ossabaw pigs (n = 8) were fed a high-fat diet for 9 months to develop visceral obesity, IR, and metabolic syndrome. Following laparotomy, mesenteric fat cryolipolysis (MFC) was performed in 5 pigs, while 3 served as sham surgery controls. The volume of the mesenteric fat was measured by computed tomography and compared with indices of glucose intolerance before and at 3 and 6 months postprocedure.MFC safely reduced mesenteric fat volume by ∼30% at 3 months, which was maintained at 6 months. Body weight did not change in either the MFC or sham surgery control groups. Measure of glycemic control, insulin sensitivity, and blood pressure significantly improved after MFC compared with sham controls.MFC reduces the volume of mesenteric fat and improves glycemic control in obese, IR Ossabaw pigs, without adverse effects.

PurposeTo assess feasibility and accuracy of point-of-care (POC) NMR-proton density fat fraction (PDFF) in phantoms and in a human pilot study in a POC setting.MethodsPOC NMR (LiverScope, Livivos, San Diego CA) PDFF measurements were obtained of certified phantoms with known PDFF values (0%-40%). In an institutional review board-approved, Health Insurance Portability and Accountability Act-compliant prospective human study, a convenience sample of participants from an obesity clinic was enrolled (November 2020 to June 2021). The inclusion criteria required body mass index (BMI)=27-40 kg/m2 and willingness to undergo POC NMR and MRI-PDFF measurements. Liver PDFF was measured by POC NMR and, within 35 days after, by a confounder corrected CSE MRI PDFF acquisition and reconstruction method. The adverse events were documented and linear regression analyses were performed.ResultsPOC NMR-PDFF measurements agreed with known phantom PDFF values (R2 =0.99). Fourteen participants were enrolled in the pilot human study. MRI-PDFF could not be obtained in 4 participants (claustrophobia reaction, n=3, exceeded size of MR scanner bore, n=1). POC NMR was unevaluable in 2 participants (insufficient signal penetration depth, n=1, failure to comply with instructions, n=1). Technical success was 11 of 13 (85%) for POC NMR PDFF. In 7 participants (4 female; 31-74 years old; median BMI 35 kg/m2 ), MRI-PDFF (range, 2.8%-18.1%), and POC NMR-PDFF (range, 3%-25.2%), agreed with R2 =0.94. POC NMR had no adverse events.ConclusionPOC NMR measures PDFF accurately in phantoms and, in a first-in-human pilot study, is feasible and accurate in adults with obesity. Further testing to determine precision and accuracy across larger and more diverse cohorts is needed.

OBJECTIVE: Obstructive sleep apnea (OSA) is common among bariatric surgery patients and is associated with perioperative risk. Preoperative screening is recommended, but some screening tools lack validation, and their relative performance is unclear in this population. The study objective was to compare the ability of four existing tools (STOP-BANG, NO-OSAS, No-Apnea, and the Epworth Sleepiness Scale [ESS]) to screen for moderate to severe OSA in a diverse bariatric cohort. METHODS: Data from patients presenting for first-time bariatric surgery who underwent a sleep study within 1 year of the initial encounter were retrospectively reviewed. Performance of the four tools for detecting moderate to severe OSA was compared based on the area under the receiver operating characteristic curves (AUC). RESULTS: Of the included 214 patients (83.2% female, median age 39 years), 45.3% had moderate to severe OSA. Based on AUC, STOP-BANG (0.75 [95% CI: 0.68–0.81], N = 185), NO-OSAS (0.76 [95% CI: 0.69–0.82], N = 185), and No-Apnea (0.69 [95% CI: 0.62–0.76], N = 190) had similar performance (P > 0.16). Compared with STOP-BANG and NO-OSAS, ESS (0.61 [95% CI: 0.54–0.68], N = 198) had a significantly lower AUC (P < 0.01). Hispanic/Latino self-identification, sex, or obesity class did not significantly modify test performance. CONCLUSIONS: STOP-BANG and NO-OSAS may be preferable to No-Apnea and ESS when screening bariatric surgery patients for moderate to severe OSA. Efforts to screen bariatric patients for OSA are recommended.

Purpose Patients with obesity and elevated serum bicarbonate suggesting obesity hypoventilation syndrome (OHS) undergoing bariatric surgery may represent a unique subgroup. Information regarding surgical outcomes in this population remains limited. We sought to test the hypothesis that an elevated bicarbonate would be an important predictor of perioperative complications (i.e., length of hospital stay) and postsurgical outcomes (i.e., weight loss at 1 year). Materials and Methods Consecutive patients undergoing bariatric surgery between January 2015 and December 2018 were included. Patients with a preoperative serum bicarbonate ≥ 27 mEq/L were classified as suspected OHS. Results Of 297 patients, the prevalence of suspected OHS based on an elevated bicarbonate was 19.5% (95% CI: 15.3 to 24.6%). Length of hospital stay was similar in the suspected OHS and non-OHS control group (1.50 vs 1.49 days, P = 0.98). The achieved weight loss from peak preoperative weight to 1 year post-surgery was less in the suspected OHS vs the control group (4.2% [95% CI 1.6 to 6.8]; P = 0.002). Conclusion Patients with serum bicarbonate ≥ 27 mEq/L as a surrogate marker for OHS experienced weight loss that was significantly less than their normal serum bicarbonate counterparts, but still achieved weight loss deemed clinically important by current guidelines. We observed no significant difference in length of hospital stay at time of surgery. Graphical abstract

Genetic variants are vital in informing clinical phenotypes, aiding physical diagnosis, guiding genetic counseling, understanding the molecular basis of disease, and potentially stimulating drug development. Here we describe two families with an ultrarare ACVR1 gain-of-function pathogenic variant (codon 375, Arginine Proline; ACVR1

Objective Obesity Medicine Education Collaborative (OMEC) was formed to develop obesity-focused competencies and benchmarks that can be used by undergraduate and graduate medical education program directors. This article describes the developmental process used to create the competencies. Methods Fifteen professional organizations with an interest in obesity collaborated to form OMEC. Using the six Core Competencies of the Accreditation Council for Graduate Medical Education as domains and as a guiding framework, a total of 36 group members collaborated by in-person meetings, email exchange, and conference calls. An iterative process was used by each working subgroup to develop the competencies and assessment benchmarks. The initial work was subsequently externally reviewed by 19 professional organizations. Results Thirty-two competencies were developed across the six domains. Each competency contains five descriptive measurement benchmarks for evaluator rating. Conclusions This set of OMEC obesity-focused competencies is the first evaluation tool developed to be used within undergraduate and graduate medical training programs for both formative and summative assessments. Routine and more robust assessment is expected to increase the competence of health care providers to assess, prevent, and treat obesity. In addition to dissemination, the competencies and benchmarks will need to undergo evaluation for further validity and practicality.

Postprandial hyperinsulinemic hypoglycemia is an uncommon yet well-established complication of Roux-en-Y gastric bypass (RYGB) that can result in serious morbidity and adversely affect quality of life. It is often unrecognized and may be difficult to diagnose. Management is challenging. As the number of bariatric procedures increases in parallel with the obesity epidemic, clinicians will be tasked to offer effective medical therapies for this complication. Two patients presented several years after RYGB with severe postprandial hypoglycemia. In one of the patients, we were able to document simultaneous postprandial hypoglycemia and hyperinsulinemia. Conventional treatment approaches, including medical nutrition therapy, acarbose, diazoxide, and octreotide, were either ineffective or limited by poor tolerance. Nifedipine and verapamil were used adjunctively with dietary modification, resulting in resolution of symptomatic hypoglycemic episodes. These agents are therapeutic options that can be used for some patients refractory to more traditional treatments. They should be tried before surgical procedures are considered for affected patients. These two cases demonstrate that calcium channel blockers may be efficacious and appropriate for select patients refractory to dietary interventions alone.

OBJECTIVE This study aimed to evaluate a possible association between the use of obesogenic medications and inadequate weight loss in a behavioral weight-management program. METHODS This is a case-control, single-center study of 666 adult patients within a Veterans Health Administration health system who participated in the MOVE! behavioral weight-loss program. The cohort was divided into responders (n = 150), patients who achieved ≥ 5% total weight loss by the end of the MOVE! program, and nonresponders (n = 516), those who achieved

BackgroundLaparoscopic sleeve gastrectomy (LSG) is one of the most commonly performed bariatric procedures and has proven effective in providing weight loss. However, considerable variance has been noted in the degree of weight loss. Physician prescription practices may be negatively affecting weight loss post-LSG and, thus, contributing to the broad range of weight loss outcomes. The aim of our study was to determine whether commonly prescribed obesogenic medications negatively affect weight loss outcomes post-LSG.Subjects/methodsThis single center retrospective cohort study performed at a University hospital included 323 patients (≥18 years) within theUniversity California, San Diego Healthcare System who underwent LSG between 2007 and 2016. We identified a list of 32 commonly prescribed medications that have weight gain as a side effect. We compared the percent excess weight loss (%EWL) of patients divided into two groups based on post-LSG exposure to obesogenic medications. A linear regression model was used to analyze %EWL at 12 months post-LSG while controlling for age, initial body mass index (BMI), and use of leptogenic medications.ResultsA total of 150 patients (Meds group) were prescribed obesogenic medications within the one-year post-LSG follow up period, whereas 173 patients (Control group) were not prescribed obesogenic medications. The Meds group lost significantly less weight compared to the Control group (%EWL ± SEM at 12 months 53.8 ± 2.4 n = 78, 65.0 ± 2.6, n = 84 respectively, P = 0.002). This difference could not be attributed to differences in age, gender, initial BMI, co-morbidities, or prescription of leptogenic medications between the two groups.ConclusionsThe use of provider-prescribed obesogenic medications was associated with worse weight loss outcomes post-LSG. Closer scrutiny of patient medications may be necessary to help improve outcomes of weight loss treatments.

Introduction Obstructive sleep apnea (OSA) is prevalent in the bariatric surgery population and has been associated with increased perioperative risk, especially if OSA is moderate-severe (apnea-hypopnea index ≥ 15/h). Consequently, screening for OSA is recommended as part of the preoperative evaluation. Several screening tools for OSA have been developed; however, some tools lack validation and their relative performance is unclear. The purpose of this study was to compare four existing screening tools (Epworth Sleepiness Scale (ESS), STOP-BANG, NO-OSAS, and No-Apnea) with regards to the ability to identify patients with moderate-severe OSA among bariatric surgery patients. Methods We retrospectively reviewed data from Jan 2015 to Mar 2019 for adult patients presenting consecutively to UC San Diego for first-time bariatric surgery who had undergone a home or in-lab sleep study (within one year of the initial encounter for bariatric surgery), which is our standard of care. We compared the accuracy of the four screening tools for detecting moderate-severe OSA based on the area under the receiver operating characteristic curves (AUC). Subgroup analyses were explored based on sex, BMI, and ethnicity (Hispanic/Latino vs non-Hispanic/Latino). Results Of the 214 patients (83.2% female, median age 39 years) included in the study, 45.4% had moderate-severe OSA. STOP-BANG (AUC 0.75 [95%CI: 0.68 to 0.81]) and NO-OSAS (AUC 0.76 [95%CI: 0.69 to 0.82]) had similar performance (p 0.62); both performed significantly better than the ESS (AUC 0.61 [95%CI: 0.54 to 0.68]; p 0.02 for both). STOP-BANG and NO-OSAS tended to perform better in the female vs male subgroup, but this finding did not reach statistical significance. Conclusion STOP-BANG and NO-OSAS are superior to the ESS when screening bariatric surgery patients for moderate-severe OSA. In future analyses we will further explore if adjustments of standard cut-offs improve test characteristics (i.e. sensitivity/specificity) when screening bariatric surgery patients (analyses ongoing). Support None.

This study aimed to evaluate a possible association between the use of obesogenic medications and inadequate weight loss in a behavioral weight-management program.This is a case-control, single-center study of 666 adult patients within a Veterans Health Administration health system who participated in the MOVE! behavioral weight-loss program. The cohort was divided into responders (n = 150), patients who achieved ≥ 5% total weight loss by the end of the MOVE! program, and nonresponders (n = 516), those who achieved 5% total weight loss. We reviewed each patient's medical records for exposure to obesogenic medication during the time of treatment.Approximately 62% (n = 411) of patients entering MOVE! had a prescription for obesogenic medications. Obesogenic medication use was associated with worse weight-loss outcomes, and participants were 37% less likely to achieve a clinically meaningful (≥ 5% total weight loss) outcome at the end of the MOVE! program (odds ratio, 0.633; 95% CI: 0.427-0.937; adjusted P = 0.022). Patients who received three or more medications (n = 72) had the greatest difficulty achieving 5% weight loss compared with the control group (odds ratio, 0.265; 95% CI: 0.108-0.646; adjusted P = 0.003).The use of provider-prescribed obesogenic medications was associated with worse weight-loss outcomes in a behavioral weight-loss program. Closer scrutiny of patient medications is necessary to help improve outcomes of weight-loss treatments.

Background Though pharmacokinetic studies suggest accelerated biologic drug clearance with increasing body weight, evidence of obesity's impact on clinical outcomes in biologic-treated patients with ulcerative colitis (UC) is inconsistent. Aim To evaluate the impact of obesity on real world response to biological therapy in patients with UC. Methods In a single-centre retrospective cohort study between 2011-2016 of biologic-treated patients with UC, we evaluated treatment response by baseline body mass index (BMI). Primary outcome was treatment failure (composite outcome of IBD-related surgery/hospitalisation or treatment modification including dose escalation, treatment discontinuation or addition of corticosteroids); secondary outcomes were risk of IBD-related surgery/hospitalisation and endoscopic remission. We conducted multivariate Cox proportional hazard analyses to evaluate the independent impact of BMI on clinical outcomes. Stratified analysis by weight-based regimens (infliximab) or fixed-dose regimens (adalimumab, golimumab, vedolizumab, certolizumab pegol) was performed. Results We included 160 biologic-treated UC patients (50% males, 55% on infliximab) with median (IQR) age 36 y (26-52) and BMI 24.3 kg/m2 (21.4-28.7). On multivariate analysis, each 1 kg/m2 increase in BMI was associated with 4% increase in the risk of treatment failure (adjusted hazard ratio [aHR], 1.04 [95% CI, 1.00-1.08]) and 8% increase in the risk of surgery/hospitalisation (aHR, 1.08 [1.02-1.14]). The effect on treatment failure was seen in patients on weight-based dosing regimens or fixed-dose therapies. Conclusion BMI is independently associated with increased risk of treatment failure in biologic-treated patients with UC, independent of dosing regimen.

Objectives We sought to evaluate the association between obesity and response to anti-tumor necrosis factor-α (TNF) agents, through a systematic review and meta-analysis. Methods Through a systematic search through January 24, 2017, we identified randomized controlled trials (RCTs) or observational studies in adults with select immune-mediated inflammatory diseases-inflammatory bowel diseases (IBD), rheumatoid arthritis (RA), spondyloarthropathies (SpA), psoriasis and psoriatic arthritis (PsA)-treated with anti-TNF agents, and reporting outcomes, stratified by body mass index (BMI) categories or weight. Primary outcome was failure to achieve clinical remission or response or treatment modification. We performed random effects meta-analysis and estimated odds ratios (OR) and 95% confidence interval (CI). Results Based on 54 cohorts including 19,372 patients (23% obese), patients with obesity had 60% higher odds of failing therapy (OR,1.60; 95% CI,1.39-1.83;I2 = 71%). Dose-response relationship was observed (obese vs. normal BMI: OR,1.87 [1.39-2.52]; overweight vs. normal BMI: OR,1.38 [1.11-1.74],p = 0.11); a 1kg/m2 increase in BMI was associated with 6.5% higher odds of failure (OR,1.065 [1.043-1.087]). These effects were observed across patients with rheumatic diseases, but not observed in patients with IBD. Effect was consistent based on dosing regimen/route, study design, exposure definition, and outcome measures. Less than 10% eligible RCTs reported outcomes stratified by BMI. Conclusions Obesity is an under-reported predictor of inferior response to anti-TNF agents in patients with select immune-mediated inflammatory diseases. A thorough evaluation of obesity as an effect modifier in clinical trials is warranted, and intentional weight loss may serve as adjunctive treatment in patients with obesity failing anti-TNF therapy.

Obesity has reached epidemic proportions, accounting for increased morbidity, disability, health care expenditures, and mortality. Certain metabolic and comorbid conditions disproportionately affect women. Unfortunately, nonsurgical options for treatment are limited. Knowledge accrued over the past 2 decades regarding physiological and hormonal determinants of weight regulation has contributed to growing evidence regarding efficacious behavioral, dietary, and pharmacologic treatments. In this review, the biology of excess adiposity is summarized in the context of a shifting paradigm, approaching obesity as a chronic metabolic disease. Relevant updates are discussed regarding long-term lifestyle approaches and novel drug therapies, with attention to some issues specific to women.

Previous reports have indicated that the early induction of interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-alpha), IL-1beta, and IL-10 is crucial for the establishment and regulation of host cell-mediated immunity to the intracellular protozoan parasite Toxoplasma gondii. In this study, we demonstrate that a soluble tachyzoite extract (soluble tachyzoite antigen) can trigger the expression of these four monokines by murine inflammatory macrophages. Further characterization revealed that the parasite molecules in soluble tachyzoite antigen responsible for monokine induction are heat stable at 100 degree C but differ in sensitivity to protease digestion. Thus, the tachyzoite factors that stimulate TNF-alpha and IL-to expression were found to be more resistant to treatment with proteinase K than those responsible for IL-12 and IL-10 induction. Similarly, while the factors responsible for the induction of all four monokines were found to be sensitive to periodate oxidation, the TNF-alpha-stimulating activity was partially resistant to treatment with the compound at a low concentration (1 mM). A further dichotomy in monokine induction signals was inferred from experiments with isoquinoline sulfonamide protein kinase inhibitors. The latter work suggested that the pathways for TNF-alpha and IL-1beta are protein kinase C dependent, while expression of IL-12 and expression of IL-10 share distinct signal transduction mechanisms involving other kinases. Together, these data argue that monokine induction by T. gondii is mediated by glycoproteins that may belong to distinct groups in terms of their biochemical properties and intracellular signaling pathways.

The CD11b/CD18 leukocyte integrin molecule mediates diverse neutrophil adherence-related functions, including cell:cell and cell:extracellular matrix attachments. To study the individual role of this leukocyte integrin in cell adherence in hematopoietic cells, we expressed the CD11b/CD18 complex on the surface of K562 cells, a cell line derived from an individual with chronic myelogenous leukemia in blast crisis. We used an amphotrophic retroviral vector designated LCD18SN, harboring the complete coding sequence for the CD18 subunit, to transfer the CD18 cDNA into K562 cells and select stable cell lines. The CD11b subunit in the expression plasmid pREP4 was transfected into these K562/CD18 cells by electroporation and stable cell clones were selected. These K562 cells possessed RNA and intracellular protein for each subunit, and they expressed the CD11b/CD18 heterodimer on the cell surface. When CD11b/CD18 expressing K562 cells were stimulated with phorbol myristate acetate (50 ng/mL) for 24 to 48 hours, these K562 cells formed dense cell:cell aggregates. This homotypic aggregation required both activation of the CD11b/CD18 complex and the induction of the counter- receptor for CD11b/CD18 on the conjugate cell. This cell line will (1) enable the structure-function relationships between cell activation and homotypic adherence to be assessed, (2) provide the opportunity to identify accessory molecules required for activation of the CD11b/CD18 complex, and (3) facilitate the identification of novel ligands for the CD11b/CD18 complex.

OBJECTIVE. We describe the findings of unenhanced chest CT in 10 patients with acute schistosomiasis.CONCLUSION. Despite the absence of pulmonary symptoms in four individuals, all patients had parenchymal abnormalities. Small pulmonary nodules were the most common finding, identified in nine patients. These nodules ranged in size from 2 to 5 mm in five patients, with larger nodules ranging up to 15 mm seen in four patients. In one patient, the only parenchymal abnormality was a single 5-mm focus of ground-glass attenuation. No relationship was seen between either the presence of pulmonary symptoms or the presence of peripheral eosinophilia and the severity of parenchymal disease. No additional significant findings were identified.

We previously demonstrated that a protein of M(r) 75,000 (p75) is localized to cortical granules (CGs) in mouse oocytes and eggs and is released upon activation or fertilization of eggs (K.E. Pierce, M. C. Siebert, G. S. Kopf, R. M. Schultz, and P. G. Calarco, 1990, Dev. Biol. 141, 381-392). To examine the temporal pattern of synthesis of p75 during the early stages of CG formation, growing oocytes, which were isolated from juvenile mice, were incubated for 4 hr in medium containing [35S]methionine, and radiolabeled proteins were immunoprecipitated using an antiserum that detects p75. Synthesis of p75 is detected at low levels in the smallest oocytes examined (less than 20 microns). Synthesis of p75 relative to total protein synthesis increases about 12-fold during oocyte growth from the 20-40 microns size and then remains constant throughout the remaining period of oocyte growth (40-70 microns). In the fully grown, germinal vesicle (GV)-intact oocyte (70-80 microns), immunoprecipitated p75 comprises approximately 1.5% of the total amount of radiolabeled protein. Three hours after the transfer of these oocytes to a medium that supports resumption of meiosis and GV breakdown in vitro, oocytes subjected to a 1-hr labeling pulse display a 35% decrease in the relative level of p75 synthesis. By 15 hr of maturation, p75 synthesis was reduced to 14% of that in the fully grown, GV-intact oocyte and this is similar to the level of p75 synthesis in ovulated eggs. The level of p75 synthesis following in vitro translation of total egg RNA is only 38% lower than that obtained from total oocyte RNA. In addition, synthesis of p75 is observed following in vitro translation of oocyte, but not egg, poly(A)+ RNA. These results are consistent with p75 synthesis during oocyte maturation being under translational control.