Design-Based Bone Marrow Biopsy Training.

INTRODUCTION: Hematology/oncology fellows must achieve bone marrow biopsy proficiency. However, opportunities for fellows to perform bone marrow biopsies on patients are highly dependent on clinical volume. An easily accessible and feasible system to practice these procedures repetitively has not been described. Other specialties use 3-dimensional (3D)-printed models to practice procedures, but hematology/oncology has not yet incorporated this novel medical education tool, which has the potential to provide such an accessible and feasible system for procedural practice. METHODS: We used design thinking to develop and pilot a bone marrow biopsy simulation using 3D-printed pelvis models. We printed and optimized 2 models through iterative prototyping. In July 2019, we conducted a 1-hour session with 9 fellows. After an anatomy review, fellows practiced biopsies using the models with faculty feedback. To evaluate feasibility, we reviewed session evaluations, measured fellow comfort, surveyed supervising attendings, and gathered fellow and attending feedback. RESULTS: Fellows rated the 3D session highly. Fellow comfort improved after orientation. Supervisors noted no difference between the 2019 fellows and prior years. Fellows praised the opportunity to rehearse mechanics, receive feedback, and internalize anatomy. Fellows suggested incorporating a female pelvis and more soft tissue. Attending feedback on the model aligned with fellow feedback. We implemented the session again in 2020 with adjustments based on feedback. CONCLUSIONS: Three-dimensional printing represents an accessible and feasible educational tool. Three-dimensional-printed models provide opportunities for iterative practice, feedback, and anatomy visualization. Future iterations should continue to incorporate user feedback to optimize model utility.

Novel measurement tool and model for aberrant urinary stream in 3D printed urethras derived from human tissue.

BACKGROUND: An estimated 10% of male adults have split or dribbled stream leading to poor hygiene, embarrassment, and inconvenience. There is no current metric that measures male stream deviation. OBJECTIVE: To develop a novel method to measure spray in normal and abnormal anatomical conformations. DESIGN, SETTING, AND PARTICIPANTS: We developed a novel platform to reliably describe spray. We used cadaveric tissues and 3D Printed models to study the impact of meatal shape on the urinary stream. Cadaveric penile tissue and 3D printed models were affixed to a fluid pump and used to simulate micturition. Dye captured on fabric allowed for spray detection. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Spray pattern area, deviation from normal location, and flowrates were recorded. Computational fluid dynamic models were created to study fluid vorticity. RESULTS AND LIMITATIONS: Obstructions at the penile tip worsened spray dynamics and reduced flow. Ventral meatotomy improved flowrate (p<0.05) and reduced spray (p<0.05) compared to tips obstructed ventrally, dorsally or in the fossa navicularis. 3D models do not fully reproduce parameters of their parent cadaver material. The average flowrate from 3D model was 10ml/sec less than that of the penis from which it was derived (p = 0.03). Nonetheless, as in cadavers, increasing obstruction in 3D models leads to the same pattern of reduced flowrate and worse spray. Dynamic modeling revealed increasing distal obstruction was correlated to higher relative vorticity observed at the urethral tip. CONCLUSIONS: We developed a robust method to measure urine spray in a research setting. Dynamic 3D printed models hold promise as a methodology to study common pathologies in the urethra and corrective surgeries on the urine stream that would not be feasible in patients. These novel methods require further validation, but offer promise as a research and clinical tool.

Hepatic bile acid metabolism and expression of cytochrome P450 and related enzymes are altered in Bsep (-/-) mice.

The bile salt export pump (BSEP/Bsep; gene symbol ABCB11/Abcb11) translocates bile salts across the hepatocyte canalicular membrane into bile in humans and mice. In humans, mutations in the ABCB11 gene cause a severe childhood liver disease known as progressive familial intrahepatic cholestasis type 2. Targeted inactivation of mouse Bsep produces milder persistent cholestasis due to detoxification of bile acids through hydroxylation and alternative transport pathways. The purpose of the present study was to determine whether functional expression of hepatic cytochrome P450 (CYP) and microsomal epoxide hydrolase (mEH) is altered by Bsep inactivation in mice and whether bile acids regulate CYP and mEH expression in Bsep (-/-) mice. CYP expression was determined by measuring protein levels of Cyp2b, Cyp2c and Cyp3a enzymes and CYP-mediated activities including lithocholic acid hydroxylation, testosterone hydroxylation and alkoxyresorufin O-dealkylation in hepatic microsomes prepared from female and male Bsep (-/-) mice fed a normal or cholic acid (CA)-enriched diet. The results indicated that hepatic lithocholic acid hydroxylation was catalyzed by Cyp3a/Cyp3a11 enzymes in Bsep (-/-) mice and that 3-ketocholanoic acid and murideoxycholic acid were major metabolites. CA feeding of Bsep (-/-) mice increased hepatic Cyp3a11 protein levels and Cyp3a11-mediated testosterone 2ß-, 6ß-, and 15ß-hydroxylation activities, increased Cyp2b10 protein levels and Cyp2b10-mediated benzyloxyresorufin O-debenzylation activity, and elevated Cyp2c29 and mEH protein levels. We propose that bile acids upregulate expression of hepatic Cyp3a11, Cyp2b10, Cyp2c29 and mEH in Bsep (-/-) mice and that Cyp3a11 and multidrug resistance-1 P-glycoproteins (Mdr1a/1b) are vital components of two distinct pathways utilized by mouse hepatocytes to expel bile acids.

Estradiol-mediated suppression of CYP1B1 expression in mouse MA-10 Leydig cells is independent of protein kinase A and estrogen receptor.

Estrogens have multifaceted roles in mammalian testis. In the present study, we focused on estradiol as a potential regulator of testicular cytochrome P450 1B1 (CYP1B1) expression and investigated the possible mechanisms involved in the estradiol-mediated suppression. CYP1B1 protein levels were measured in the testes of rats that were treated with 17ß-estradiol benzoate (1.5 mg/kg) at different stages of development. In addition, CYP1B1 mRNA levels were measured in mouse MA-10 Leydig tumor cells treated with (a) various concentrations of 17ß-estradiol benzoate, (b) 17ß-estradiol benzoate in the presence of exogenous luteinizing hormone (LH), or (c) 17ß-estradiol benzoate in the presence of ICI 182,780, a competitive steroidal antagonist of estrogen receptors (ERs). Treatment of neonatal, pubertal, or adult rats with 17ß-estradiol benzoate was associated with a reduction of approximately 90% in testicular CYP1B1 protein content compared to age-matched controls. Treatment of MA-10 cells with 17ß-estradiol benzoate (10-500 nM) produced a concentration- and time-dependent decrease in CYP1B1 mRNA levels, but had no effect on LH receptor mRNA levels or on protein kinase A (PKA) activity. However, 17ß-estradiol benzoate (10-500 nM), regardless of the concentration tested, failed to attenuate the LH-elicited increase in CYP1B1 mRNA or PKA activity in MA-10 cells that were co-treated with LH and estradiol. Similarly, ICI 182,780 (10-1000 µM) did not reverse the suppressive effect of estradiol on CYP1B1 mRNA expression in MA-10 cells co-treated with estradiol and ICI 182,780. The results indicate that downregulation of testicular CYP1B1 by estradiol was independent of PKA activity and was not mediated by ERs in MA-10 cells.

Developmental expression and endocrine regulation of CYP1B1 in rat testis.

Mammalian testis expresses xenobiotic-metabolizing enzymes, including cytochrome P450 1B1 (CYP1B1), which catalyzes the bioactivation of procarcinogens and other chemicals. The factors that control testicular expression of CYP1B1 are largely not known. In the present study, we investigated the influence of age and pituitary, gonadal, and thyroid hormones on CYP1B1 expression in rat testis. Immunoblot analysis showed that testicular CYP1B1 protein was expressed at a level of 5.9+/-2.0 (mean+/-S.E.M.) pmol/mg microsomal protein in prepubertal 22-day-old rats, whereas it was 6.6-fold greater in pubertal rats (34 days old) and 9.6-fold greater in adult rats (84-91 days old). Hypophysectomy decreased testicular CYP1B1 protein levels by 69% in adult rats when compared with intact rats of the same age. Intermittent subcutaneous administration of growth hormone to hypophysectomized adult rats further decreased it by 63%. Luteinizing hormone (LH) and follicle-stimulating hormone increased CYP1B1 expression in hypophysectomized rats, but they did not restore protein levels to those in intact adult male rats. Prolactin treatment alone had no effect; however, it potentiated the increase in CYP1B1 mRNA and protein expression by LH. 3,5,3'-Triiodothyronine, but not thyroxine, resulted in a small increase in testicular CYP1B1 protein levels. Likewise, treatment of hypophysectomized rats with testosterone propionate elicited a small increase in CYP1B1 protein expression. In contrast, treatment of intact adult male rats with 17beta-estradiol benzoate decreased it by 91%. Overall, our findings indicate that rat testicular CYP1B1 protein expression is subject to developmental and endocrine control, with multiple hormones playing a role.

Engineered allogeneic chondrocyte pellet for reconstruction of fibrocartilage zone at bone-tendon junction--a preliminary histological observation.

This study examined histologically the potential of using allogeneic cultured chondrocyte pellet (CCP) in enhancing bone-tendon junction (BTJ) healing using a rabbit partial patellectomy model. Chondrocytes isolated from the cartilaginous ribs of 6-week-old New Zealand white rabbits were cultured for 14 days to form CCP. Partial patellectomy was performed on 30 18-week-old rabbits. After removal of the distal third patella, the BTJ gap was repaired surgically with or without CCP interposition. Four samples of patella-patellar tendon complexes (PPTC) for each group were harvested each at 8, 12, and 16 weeks; and two additional PPTC for each group were harvested at 2, 4, and 6 weeks for early observation of fibrocartilage zone regeneration, histologically. Results showed that CCP interposition demonstrated earlier structural integration at the BTJ after 8, 12, and 16 weeks of healing, and formation of a fibrocartilage zone like structure, compared with control specimens. In addition, no immune rejection was observed in CCP experimental group. The results suggested that CCP had a stimulatory effect on BTJ healing. This bioengineering approach might have potential clinical application in treatment of difficult BTJ healing. However, systemic histomorphometric, immunological tests, and biomechanical evaluations are needed before any clinical trials.