Impact of employer-covered planned oocyte cryopreservation on decision-making for medical training

PURPOSE

To characterize how employer coverage of planned oocyte cryopreservation (POC) might impact medical career decision-making.

METHODS

A cross-sectional survey was distributed to all medical students at two large academic programs in December 2022 to better understand attitudes towards childbearing, POC, and how employer coverage of POC might influence future career decisions.

RESULTS

Of the 630/1933 (32.6%) medical students who participated, 71.8% identified as women and 28.1% as men. More women (89.2%) than men (75.1%, P < 0.001) felt pressure to delay childbearing. Regarding childbearing, women more than men were concerned about the physical demand of residency (76.5% vs. 50.8%, P < 0.001), stigma in residency hiring practices (41.2% vs. 9.0%, P < 0.001), and parental leave interfering with team dynamics (49.6% vs. 20.9%, P < 0.001). Respondents were more likely to pursue POC if it were covered by residency employer health insurance (60.0% vs. 11.6%, P < 0.001). Women were more likely than men to state that employer-sponsored POC would influence their residency ranking (46.0% vs. 23.7%, P < 0.001), pursuit of additional degrees (50.9% vs. 30.5%, P < 0.001), and pursuit of fellowship training (50.9% vs. 30.5%, P < 0.001). Additionally, 25.4% of women and 19.8% of men felt their choice in medical specialty would be impacted by employer-sponsored POC.

CONCLUSIONS

Medical students, particularly women, feel pressure to delay childbearing during medical training and are concerned about future fertility. Both male and female students were interested in employer-sponsored POC and more likely to pursue it with financial coverage. Further research is needed to determine the full impact of employer-sponsored POC on medical career decision-making.

Pregnancy Outcomes in Patients with Obstructed Hemivagina Ipsilateral Renal Agenesis

STUDY OBJECTIVE

Obstructed hemivagina with ipsilateral renal agenesis (OHVIRA) is a rare congenital Müllerian anomaly. We sought to explore the impact of OHVIRA on pregnancy outcomes.

METHODS

A retrospective chart review identified 8 patients with an OHVIRA diagnosis and at least 1 documented pregnancy. Data collected included demographic characteristics, age at diagnosis and repair, gynecologic history, and pregnancy outcomes. Descriptive analysis was performed.

RESULTS

Twenty-three pregnancies were identified among the 8 patients (range 1-5 pregnancies per patient), resulting in 9 term births, 6 preterm births, and 8 first-trimester spontaneous abortions. The most common pregnancy complications were fetal growth restriction (2/15) and preeclampsia with severe features (2/15). The average gestational age at delivery was 37 2/7 weeks; however, 60% (9/15) of live births were at term. Two patients delivered after going into preterm labor, one of whom also had preterm premature rupture of membranes. Of the 15 live births, there were 10 cesarean deliveries, 4 vaginal deliveries, and 1 forceps-assisted vaginal delivery. Three patients (30%) underwent primary cesarean deliveries due to fetal malpresentation. Five live births were repeat cesarean deliveries, and 2 were unscheduled cesareans, at 34 and 36 weeks, due to preeclampsia with severe features.

CONCLUSION

This study is among the first to examine pregnancy outcomes in patients with OHVIRA. Among these patients, there were 23 total pregnancies, with higher incidences of spontaneous abortion, preterm birth, breech presentation, and cesarean delivery compared with the general population. This descriptive data set addresses a knowledge gap to help clinicians more effectively advise patients with OHVIRA about pregnancy outcomes.

Postoperative Bleeding Two Weeks After Longitudinal Vaginal Septum Resection with the LigaSure Device: A Case Report

BACKGROUND

A longitudinal vaginal septum (LVS) is a rare congenital anomaly often identified during adolescence. Surgical removal is a mainstay in treatment of symptomatic cases; however, there is variation in the techniques used. Little is known about the risk for postoperative complications associated with novel methods.

CASES

We present the cases of 2 adolescent females, ages 15 and 22, diagnosed with an LVS who elected to undergo surgical removal. A LigaSure device was used for resection, and both individuals experienced significant postoperative bleeding almost 2 weeks following resection.

SUMMARY AND CONCLUSIONS

This report outlines two occurrences of postoperative bleeding after LVS resection, which may suggest inadequate surgical site hemostasis with use of the LigaSure apparatus. Further research on outcomes related to this technique is needed.

"They had the lunch lady coming up to assist": The experiences of menarche and menstrual management for adolescents with physical disabilities

BACKGROUND

Menarche is a pivotal time in an adolescent's life but can be experienced differently by those with physical disabilities. Parents typically serve as the primary educators and support for their daughters during this time. Little is known about the parent's perspective of their daughter's experience preparing for menarche and learning to manage menses.

OBJECTIVE

We sought to understand the parent's perspective of the experience of their daughter with a physical disability around menarche and their preferences for health care provider support.

METHODS

Individual semi-structured interviews were conducted with 21 parents of a daughter with a physical disability ages 7-26. Interviews were coded by 2 reviewers using Grounded Theory, with disagreements resolved by consensus.

RESULTS

Six themes emerged regarding the parent's perception of the experiences, including 1) variation in emotional responses to menarche, 2) parent's perception of their daughter's experience with menses and menstrual symptoms, 3) cross-section of disability and menstrual management, 4) menstrual management at school, 5) parental knowledge correlating to daughter's preparation for menarche, and 6) desires for health care provider support.

CONCLUSIONS

All parents reported that their daughters faced challenges during menarche, ranging from emotional distress to dealing with the inaccessibility of hygiene products. Managing periods at schools was particularly burdensome. Parents who were better educated about what to expect were better able to prepare their daughters, but had difficulties finding informed, supportive providers. Health care providers should provide both anticipatory guidance and holistic, respectful, and equitable options for the management of menstrual symptoms.

The Utility of Pelvic Ultrasounds in Adolescents Presenting to the Emergency Department with Abnormal Uterine Bleeding

STUDY OBJECTIVE

To analyze what factors influence a provider's decision to order a pelvic ultrasound (PUS) in the emergency department (ED) for adolescents with abnormal uterine bleeding (AUB), to determine if endometrial stripe (EMS) measurements are used in treatment decisions, and to evaluate if treatment outcomes differ based on EMS thicknesses.

METHODS

Retrospective chart review of patients aged 11-19 presenting to the ED with AUB from 2006 to 2018. Those receiving a PUS were divided into three EMS groups: ≤5 mm, 6-9 mm, and ≥10 mm. Outcomes were evaluated in admitted patients by progress notes indicating resolution of bleeding. Cross-tab, χ2, and logistic and linear regression analysis were performed.

RESULTS

Of 258 adolescents meeting study criteria, 113 (43.8%) had a PUS. None had an abnormality. A PUS was more likely to be performed in patients with lower hemoglobin values (P < .003). Provider decision to order a PUS did not differ by age or bleeding duration (P > .1). Among those with a PUS, 67 (59%) received hormonal therapy (pill, progestin-only, IV estrogen). There were no significant differences in treatment choices based on EMS (P < .061) or, among the 44 admitted patients (17%), in the time it took bleeding to stop after initiating treatment (pill: P = .227, progestin-only: P = .211, IV estrogen: P = .229).

CONCLUSION

In adolescents with AUB in the ED, performing a PUS was more common in those with low hemoglobin. EMS thickness did not appear to affect treatment decisions or inpatient outcomes. Larger studies are needed to confirm the current findings and determine if PUS is needed in the evaluation of AUB.

Norethindrone dosing for adequate menstrual suppression in adolescents

OBJECTIVES

We sought to study factors predictive of achieving menstrual suppression with norethindrone vs. norethindrone acetate in adolescents, as optimal dosing is unknown. Secondary outcomes included analyzing prescriber practices and patient satisfaction.

METHODS

We performed a retrospective chart review of adolescents ages <18 years presenting to an academic medical center from 2010 to 2022. Data collected included demographics, menstrual history, and norethindrone and norethindrone acetate use. Follow-up was measured at one, three, and 12 months. Main outcome measures were starting norethindrone 0.35 mg, continuing norethindrone 0.35 mg, achieving menstrual suppression, and patient satisfaction. Analysis included Chi-square and multivariate logistic regression.

RESULTS

Of 262 adolescents initiating norethindrone or norethindrone acetate, 219 completed ≥1 follow-up. Providers less often started norethindrone 0.35 mg for patients with body mass index ≥25 kg/m2, prolonged bleeding, or younger age at menarche, but more often for patients who were younger, had migraines with aura, or were at risk of venous thromboembolism. Those with prolonged bleeding or older age at menarche were less likely to continue norethindrone 0.35 mg. Obesity, heavy menstrual bleeding, and younger age were negatively associated with achieving menstrual suppression. Patients with disabilities reported greater satisfaction.

CONCLUSIONS

While younger patients more often received norethindrone 0.35 mg vs. norethindrone acetate, they were less likely to achieve menstrual suppression. Patients with obesity or heavy menstrual bleeding may achieve suppression with higher doses of norethindrone acetate. These results reveal opportunities to improve norethindrone and norethindrone acetate prescribing practices for adolescent menstrual suppression.

The relationship between estrogen and subsequent growth restriction among adolescents with heavy menstrual bleeding at menarche

OBJECTIVES

We sought to evaluate the impact of estrogen-containing treatment for heavy menstrual bleeding (HMB) on subsequent height compared to progesterone-only or non-hormonal treatment when initiated at menarche.

METHODS

We performed a retrospective chart review of adolescent females aged 10-15 years who presented to an institution-affiliated outpatient, inpatient, or emergency setting for management of HMB within three months of menarche. Growth records over a 2 year period starting at menarche were recorded, and comparisons made among patients treated with 1) estrogen, 2) progesterone, and 3) non-hormonal methods (controls). Groups were compared using bivariate analysis with Chi-square or Fisher's exact test and linear regression.

RESULTS

In an analysis of 80 patients at 24 months, the mean increase in height from menarche was 6.4 cm among controls (n=54), 7.2 cm among the progesterone-only group (n=10), and 3.8 cm among the estrogen group (n=16). The estrogen group's increase in height was significantly lower than the control group's, by a mean of 1.8 cm (p=0.04). Change in height did not differ significantly between the progesterone and control groups (p=0.87). Additionally, for every year younger at menarche, there was 1 fewer cm of growth (change in height) at 24 months after menarche (p<0.002).

CONCLUSIONS

Estrogen-containing treatment for HMB initiated within three months of menarche was associated with reduced growth at 24 months compared to progesterone-only or non-hormonal methods. The clinical applicability of the estrogen group's 1.8 cm absolute reduction in height may have considerable significance for those who are shorter at baseline.

Sonographic Predictors of Ovarian Torsion in Premenarchal Girls

STUDY OBJECTIVE

To identify preoperative transabdominal sonographic predictors of surgically-confirmed ovarian torsion (OT) in premenarchal girls.

METHODS

Retrospective case-control study of 32 premenarchal girls aged 0-12 undergoing surgery for OT (cases) or a non-torsed ovarian mass (controls) from 2006-2017 at a single academic center. Cases had ICD-9/10 codes for torsion of the ovary, adnexa, ovarian pedicle, or fallopian tube and surgically-confirmed OT; controls had codes for ovarian mass or cyst and surgically-confirmed absence of OT. Preoperative transabdominal ultrasounds were analyzed by three radiologists blinded to final diagnosis. Chi-square, Fisher's exact, and Student's t-test were used for statistical comparisons.

RESULTS

From 2016-2017, 32 patients presented with acute abdominal pain or symptoms concerning for ovarian mass requiring ultrasound imaging and subsequent diagnostic laparoscopy-24 (75.0%) had confirmed OT by laparoscopy; eight (25.0%) did not. Mean age in both groups was similar (7.3±2.9 years). Preoperative sonographic variables significantly associated with OT included presence of a simple cyst (20.8% vs 12.5%), ovarian heterogeneity (100% vs 12.5%), presence of peripheralized follicles (70.8% vs 0%), and asymmetry of color Doppler (75.0% vs 37.5%)-all p<0.05. Presence of free fluid, arterial color Doppler, and a whirlpool sign were not predictive of OT.

CONCLUSION

In premenarchal patients, while certain variables on transabdominal sonography predicted surgically-confirmed OT, only the presence of peripheralized follicles was unique to girls with OT. The decision to proceed with diagnostic laparoscopy for suspected OT can be aided by these specific sonographic findings but should ultimately be based on high clinical suspicion.

Assessment of Iron Status in Adolescents Presenting to the Emergency Department With Heavy Menstrual Bleeding

OBJECTIVE

Iron deficiency is extremely common in adolescents with heavy menstrual bleeding (HMB) presenting to the emergency department; however, patients are rarely screened for this. The objective of this study was to evaluate screening for iron deficiency in adolescents presenting to the emergency department for HMB.

METHODS

This is a secondary analysis of a single-center, cross-sectional observational study using retrospective chart review. The study subjects are adolescents ages 11 to 19 years with International Classification of Diseases, Ninth Revision, Clinical Modification/International Classification of Diseases, Tenth Revision, Clinical Modification, codes for HMB who presented to the emergency department at a national tertiary care hospital from 2006 to 2018. Pregnant adolescents with HMB were excluded. Chart abstraction for demographic data, symptoms, laboratory tests, treatments, and outcomes was performed. The main outcome measure was the number of adolescents who had an iron evaluation in the emergency department and were discharged on oral iron.

RESULTS

Of the 258 nonpregnant adolescents who sought care for HMB in the emergency department, 225 (87.2%) were evaluated with serum hemoglobin testing. Ninety-four (41.7%) of those tested were anemic. Only 23 of the 258 patients (8.9%) had iron studies (serum ferritin) performed; 18 of 23 (78.3%) had iron deficiency and 21 of 23 (92.3%) were anemic. Subjects presenting with fatigue, headache, or palpitations were more likely to have iron studies performed than those without these symptoms (all P < 0.01). Thirty-two of the 258 subjects (12.4%) were discharged on oral iron therapy, which included only 15 of the 18 subjects (83.3%) with iron deficiency determined by ferritin testing.

CONCLUSIONS

Adolescents presenting to the emergency department with HMB are at significant risk of iron deficiency but are not being screened or treated, which may have significant consequences.

Considerations in Adolescent Use of the Etonogestrel Subdermal Implant: A Cohort Study

Objectives: To describe bleeding patterns and other side effects in adolescent implant users and characterize their impact on early discontinuation of the implant.

Study Design: This is a retrospective cohort study of female patients under 18 years who had an implant placed from 2013 to 2018. Data were collected on demographics, medical history, and side effects.

Results: Of 212 adolescents, the average age at insertion was 16 years and 84% desired placement for contraception. Common side effects included AUB (80%), mood changes (10%), and perceived weight gain (9%). Most (76%) used the implant for at least 12 months. Average time to removal was 22.1 months (SD 13.0 months) and this did not depend on presence of side effects. Twenty-seven percent of teens were able to achieve amenorrhea. Adolescents with frequent or prolonged bleeding were more likely to have implant removal prior to 12 months than those with other bleeding patterns (p = 0.003). Early removal was also more common in girls reporting weight or mood issues than those who did not (p < 0.001 and p = 0.045, respectively). BMI increased in 64% of adolescents. Average percentage change in BMI was 3.2% (0.87 kg/m²). There was no difference in baseline use of any mood-modulating medications in patients who did and did not complain of mood side effects following implant placement (p = 0.801).

Conclusion: Characterization of bleeding patterns following implant placement in adolescents have not previously been reported. Prolonged or heavy bleeding, mood issues, and perceived weight gain were associated with earlier removal of the implant. A relatively small number had early removal of the implant due to weight or mood complaints. Therefore, a history of obesity, depression, or other mood disorders should not be a deterrent to implant placement.

Interdisciplinary Care and a Focus on Fertility Preservation When Multi-cystic Ovaries Cause Ovarian Torsion: A Case of a 9-year-old Girl with Severe, Undiagnosed Hypothyroidism

BACKGROUND

Ovarian torsion can occur in Van Wyk Grumbach syndrome, a disorder characterized by severe primary hypothyroidism and ovarian enlargement. To date, all documented cases of torsion in this setting describe oophorectomy, which has significant hormonal and fertility implications.

CASE

A 9-year-old pubertal girl presented to the emergency room with abdominal pain. Magnetic resonance imaging demonstrated bilateral, multi-cystic ovaries. Operative laparoscopy confirmed unilateral adnexal torsion, and detorsion without oophorectomy was accomplished. Postoperative laboratory tests revealed severe primary hypothyroidism. Ovarian size was reduced with hormone replacement therapy.

SUMMARY AND CONCLUSION

This case demonstrates that prompt interdisciplinary intervention and awareness of severe hypothyroidism as a cause of ovarian torsion related to enlarged, multi-cystic ovaries may reduce the rate of oophorectomy, allowing preservation of pediatric patients' future fertility, and reducing morbidity postoperatively through prompt, long-term thyroid supplementation.

Outpatient Management of Heavy Menstrual Bleeding in Adolescent and Young Women with Inherited Platelet Function Disorders

STUDY OBJECTIVE

To assess the treatment patterns and efficacy of hormonal (HM) and non-HM (NHM) management of heavy menstrual bleeding (HMB) in young women with inherited platelet function disorders (IPFDs).

DESIGN, SETTING, AND PARTICIPANTS

A retrospective chart review was performed of outpatient treatment of HMB in female patients age 9-25 years who were diagnosed with IPFDs and referred to gynecology and/or hematology at a tertiary care hospital between 2006 and 2018.

INTERVENTIONS

The study sample was identified using billing codes for IPFDs. Data on HM and NHM treatments and outcomes over a one- to two-year period were collected. Initial treatment was defined as the first treatment prescribed after referral. Descriptive statistics, Pearson χ², and t tests were used for analysis.

MAIN OUTCOME MEASURES

Treatment failure was defined as a change in treatment method because of continued bleeding.

RESULTS

Thirty-four girls met inclusion criteria. After their initial visit, 19/34 (56%) were treated with HM, 12/34 (35%) with NHM, 2/34 (6%) with a combination of methods, and 1/34 (3%) were untreated. Initial treatment failed in 19/34 (56%) and those patients subsequently required a mean of 2 additional treatments during follow-up. Of the 34 included, 6/34 (18%) remained uncontrolled despite numerous treatment changes and 2/34 (6%) because of noncompliance. When control was achieved, 7/26 (27%) of patients were receiving combined oral contraceptives and 6/26 (23%) desmopressin acetate.

CONCLUSION

HMB in girls with IPFDs can be difficult to control despite ongoing follow-up and treatment changes. Although the most effective treatment for HMB in young women with IPFDs was not identified, these findings will help providers and patients with setting expectations. Prospective studies are needed to develop recommendations on best practices.

Trends in Emergency Department Visits among Adolescents with Abnormal Uterine Bleeding

STUDY OBJECTIVE

To explore trends over time in the utilization of the Emergency Department (ED) for adolescents with abnormal uterine bleeding (AUB).

DESIGN

Retrospective cross-sectional study.

SETTING

Nationwide Emergency Department Sample database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, Rockville, MD).

PARTICIPANTS

Subset of adolescents aged 10-19 years from overall cohort of women aged 10-49 years.

INTERVENTIONS

All ED visits from 2010-2014 for which International Classification of Diseases, ninth revision codes for AUB were listed as the principal diagnosis were compared. Health insurance coverage, demographic factors, hospital characteristics, comorbid anemia, and comorbid bleeding disorders were explored.

MAIN OUTCOME MEASURES

Number of visits, ED disposition, blood transfusions, and billing for pelvic ultrasound.

RESULTS

There were an estimated 262,939 ED visits nationally for women aged 10-49 years for AUB in 2014. Of these, 12.7% (33,511/262,939) were from adolescents aged 10-19 years. The number of adolescent visits with an AUB diagnosis declined by 11% from 2010-2014 (37,642 vs 33,511; P = .026), while visits by patients aged 20-49 did not change significantly (215,309 vs 229,428; P = .19). The number of adolescent visits for which Medicaid was the primary payer increased slightly, from 17,283 to 18,785, from 2010 to 2014 (P = .152), while the number using self-pay decreased from 8769 (23.4%) in 2010 to 5146 (15.4%) in 2014 (P < .0001).

CONCLUSION

ED visits among adolescents with AUB decreased from 2010 to 2014. There was a sharp reduction in the number of visits funded by self-pay and a slight increase in visits funded by Medicaid.

Risk Factors for Endometrial Cancer or Hyperplasia in Adolescents and Women 25 Years Old or Younger

STUDY OBJECTIVE

To evaluate characteristics of young women with endometrial hyperplasia or cancer.

DESIGN

Retrospective chart review.

SETTING

Tertiary care referral center.

PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES

We included 10- to 25-year-old young women seen at a single institution between 2006 and 2017 with International Classification of Diseases 9th and 10th revision codes for endometrial cancer or hyperplasia (cases), or who underwent an endometrial biopsy with other benign pathologic diagnoses (controls). Exclusions included a diagnosis of Lynch syndrome. Comparisons were made using χ², Fisher exact, and nonparametric Wilcoxon rank tests.

RESULTS

Sixty-nine patients were identified: 13 cases, 54 controls, and 2 exclusions. Of the 13 cases, 3 had endometrial cancer, 5 had complex atypical hyperplasia (now called endometrioid intraepithelial neoplasia), and 5 had hyperplasia without atypia. A higher proportion of cases had a body mass index (BMI) greater than 30, compared with controls (76.9% vs 40.4%; P < .03). The proportion of patients who had a BMI greater than 30 and were smokers was significantly higher among cases (38.5% vs 9.3%; P < .02). The proportion of patients with a history of polycystic ovary syndrome (PCOS) and smoking was also significantly different between groups (30.8% vs 3.7%; P < .01).

CONCLUSION

In women aged 25 years and younger with endometrial sampling, a BMI greater than 30 was statistically more common in patients with endometrioid intraepithelial neoplasia or cancer. Although smoking or PCOS alone was not related to endometrial hyperplasia or cancer in this small cohort study, there might be a relationship between endometrial abnormalities and multiple exposures, including smoking and BMI greater than 30 or smoking and a history of PCOS.

Pediatric Resident Training in Prepubertal Vulvar Conditions

STUDY OBJECTIVE

To assess pediatric resident training in diagnosing and managing prepubertal gynecologic conditions.

DESIGN

Voluntary 32-question survey e-mailed to participants.

SETTING

E-mail contact through the American Academy of Pediatrics listserv.

PARTICIPANTS

Seven thousand seventy-five US pediatrics and combined internal medicine-pediatric residents.

INTERVENTIONS

Descriptive analysis including χ² tests was performed on survey results.

MAIN OUTCOME MEASURES

Residents' training experiences and comfort, confidence, and knowledge in evaluating pediatric gynecologic concerns.

RESULTS

In the 866 of 7075 (12%) completed surveys, a greater proportion of residents reported they were "very" or "extremely" comfortable talking to parents about general pediatric topics compared with gynecologic topics (88.5% vs 30.4%; P < .001). Similarly, they reported being "very" or "extremely" confident diagnosing general pediatric conditions compared with prepubertal gynecologic conditions (87.6% vs 32.8%; P < .001). These differences were also observed according to residency year (comfort: first year, 10.2% vs third/fourth year, 39.9%; P < .001; confidence: first year, 22.5% vs third/fourth year, 37.6%; P < .001). Residents learned about vulvovaginal concerns from attendings in clinic (79.8%), residency-specific didactics (34.7%), and conferences, meetings, and workshops (24.1%). Confidence examining, diagnosing, and treating vulvovaginitis was associated with participation in any learning activity and exposure to more than 5 patients with this concern. Additional education or training in prepubertal vulvovaginal conditions was requested by 97% of residents.

CONCLUSION

Our findings suggest that pediatric residents are lacking in comfort, confidence, and knowledge of prepubertal vulvovaginal conditions, especially compared with general pediatric topics. Although this improves during training, it remains low, and more education is indicated and desired by residents.

Serologic and animal inoculation studies of a communal outbreak of viral hepatitis, type A

Sera from individuals in an outbreak of viral hepatitis in a multifamily household, probably spread by contaminated food, were studied for antibodies to hepatitis A virus (anti-HAV), and selected acute phase sera were inoculated into marmosets. Significant rises in anti-HAV titers between acute and convalescent sera occurred in all of 15 individuals in the outbreak who experienced serum enzyme elevations and in one of 14 individuals whose serum enzyme levels remained normal. The remaining 13 individuals in the latter group had antibody levels in both early and late sera compatible with residual immunity from prior HAV infections and correlating with resistance to reinfection. Groups of marmosets were infected with acute phase sera from two of the cases; in both instances the inoculated sera contained substantial levels of anti-HAV. The marmosets developed specific anti-HAV seroconversions as well as enzyme elevations.

Survival of human sickle-cell erythrocytes in heterologous species: response to variations in oxygen tension

Survival characteristics, after transfusion, of erythrocytes from patients with homozygous sickle-cell disease were studied in rats. The study was made possible by previous injection of the animals with ethyl plamitate, which depressed reticuloendothelial system function, and with a factor in cobra venom that inactivated complement. This treatment prevented the rapid phagocytosis and intravascular hemolysis of donor erythrocytes that usually follow a heterologous transfusion. Both immediate after transfusion recovery and survival of (51)Cr-labeled sickle erythrocytes were decreased in comparison to the values obtained for control erythrocytes from individuals without sickle-cell anemia. Survival of sickle erythrocytes was improved during exposure of the animals to 100% O(2). Hypoxia (7-10% O(2)) resulted in the abrupt removal of 35-60% of sickle erythrocytes from the rats' circulation. Variations in oxygen tension did not affect survival of control erythrocytes. The usefulness of this convenient animal model for the study of sickle-cell anemia is suggested by the similarities between our results and the behavior of sickle erythrocytes in humans. The system may also be suitable for studying a wide variety of other human erythrocyte disorders.