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Dive into the research topics where Jon A. Jacobson is active.

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Featured researches published by Jon A. Jacobson.


The American Journal of Gastroenterology | 2005

One-year intense nutritional counseling results in histological improvement in patients with nonalcoholic steatohepatitis : A pilot study

Mary Ann Huang; Joel K. Greenson; Cewin Chao; Lilian Anderson; Debra Peterman; Jon A. Jacobson; Dawn Emick; Anna S. Lok; Hari S. Conjeevaram

BACKGROUND AND AIM:In individuals with biopsy-proven non-alcoholic steatohepatitis (NASH), short-term weight loss has been shown to improve biochemical abnormalities; however, its effect on liver histology is largely unknown. The aim of the article is to determine if dietary intervention is effective in improving histological features of steatohepatitis in patients with biopsy-proven NASH.METHODS:Twenty-three patients (11M/12F) with BMI >25 kg/m2 and biopsy-proven NASH received standardized nutritional counseling aimed at reducing insulin resistance (IR) and weight. Blood tests were checked at baseline and every 1–4 months, and liver biopsy was repeated at month 12. IR was assessed by the homeostasis model assessment (HOMA). Liver biopsies were scored according to modified Brunt criteria for NASH. “Histologic response” was defined as a reduction in total NASH score of ≥2 points with at least one point being in the non-steatosis component.RESULTS:Sixteen patients (8M/8F) completed 12 months of dietary intervention, and 15 underwent repeat liver biopsies. At month 12, mean weight decreased from 98.3 to 95.4 kg. Mean waist circumference, visceral fat, fasting glucose, IR, triglycerides, AST, ALT, and histologic score were all reduced but the difference was not significant. Nine patients had a histologic response, six had stable scores, and none had a worsened score. Compared to patients with unchanged histologic scores, patients with improved scores had significantly greater reduction in weight, waist circumference, AST, ALT, steatosis grade, and total NASH score.CONCLUSION:Among patients who successfully completed 1 yr of intense dietary intervention, nine of 15 patients with NASH displayed histologic improvement. This pilot study suggests that dietary intervention can be effective in improving histology in patients with biopsy-proven NASH.


American Journal of Sports Medicine | 2011

When Do Rotator Cuff Repairs Fail? Serial Ultrasound Examination After Arthroscopic Repair of Large and Massive Rotator Cuff Tears

Bruce S. Miller; Brian K. Downie; Robert B. Kohen; Theresa G. Kijek; Bryson P. Lesniak; Jon A. Jacobson; Richard E. Hughes; James E. Carpenter

Background: Despite advances in arthroscopic repair of rotator cuff tears, recurrent tears after repair of large and massive tears remain a significant clinical problem. The primary objective of this study was to define the timing of structural failure of surgically repaired large and massive rotator cuff tears by serial imaging with ultrasound. The secondary objective of this study was to investigate the association between recurrent tears and clinical outcome after rotator cuff repair. Hypothesis: Recurrent tear after arthroscopic repair of large rotator cuff tears is more likely to occur late (>3 months) in the postoperative period and will be associated with inferior clinical outcome scores. Study Design: Cohort study; Level of evidence, 3. Methods: Twenty-two consecutive patients with large (>3 cm) rotator cuff tears underwent arthroscopic repair with a standardized technique. Serial ultrasound examinations were performed at 2 days, 2 weeks, 6 weeks, 3 months, 6 months, 12 months, and 24 months after surgery. Western Ontario Rotator Cuff (WORC) Index scores were also collected at these time points. Results: Nine (41%) of the 22 arthroscopically repaired rotator cuff tears demonstrated recurrent tears. Seven of the 9 retears occurred within 3 months of surgery, and the other 2 occurred between 3 and 6 months. No retears occurred after 6 months. At 24-month follow-up, WORC scores favoring intact rotator cuffs over retears approached statistical significance (mean WORC intact 123.9 vs retear 659.8; P = .07). Conclusion: Recurrent rotator cuff tears are not uncommon after arthroscopic repair of large and massive tears. These recurrent tears appear to occur more frequently in the early postoperative period (within the first 3 months) and are associated with inferior clinical outcomes.


Arthritis Care and Research | 2009

Knee osteoarthritis in obese women with cardiometabolic clustering

MaryFran Sowers; Carrie A. Karvonen-Gutierrez; Riann M. Palmieri-Smith; Jon A. Jacobson; Yebin Jiang; James A. Ashton-Miller

OBJECTIVE To assess the role of obesity and metabolic dysfunctionality with knee osteoarthritis (OA), knee joint pain, and physical functioning performance, adjusted for joint space width (JSW) asymmetry. METHODS Knee OA was defined as a Kellgren/Lawrence score > or =2 on weight-bearing radiographs. Obesity was defined as a body mass index > or =30 kg/m2. Cardiometabolic clustering classification was based on having > or =2 of the following factors: low levels of high-density lipoprotein cholesterol; elevated levels of low-density lipoprotein cholesterol, triglycerides, blood pressure, C-reactive protein, waist:hip ratio, or glucose; or diabetes mellitus. The difference between lateral and medial knee JSW was used to determine joint space asymmetry. RESULTS In a sample of women (n = 482, mean age 47 years), prevalences of knee OA and persistent knee pain were 11% and 30%, respectively. The knee OA prevalence in nonobese women without cardiometabolic clustering was 4.7%, compared with 12.8% in obese women without cardiometabolic clustering and 23.2% in obese women with cardiometabolic clustering. Nonobese women without cardiometabolic clustering were less likely to perceive themselves as limited compared with women in all other obesity/cardiometabolic groups (P < 0.05). Similar associations were seen with knee pain and physical functioning measures. The inclusion of a joint space asymmetry measure was associated with knee OA but not with knee pain or physical functioning. CONCLUSION Knee OA was twice as frequent in obese women with cardiometabolic clustering compared with those without, even when considering age and joint asymmetry. Obesity/cardiometabolic clustering was also associated with persistent knee pain and impaired physical functioning.


Clinical Cancer Research | 2010

Efficacy of imatinib in aggressive fibromatosis: results of a phase II multicenter Sarcoma Alliance for Research through Collaboration (SARC) trial

Rashmi Chugh; J. Kyle Wathen; Shreyaskumar Patel; Robert G. Maki; Paul A. Meyers; Scott M. Schuetze; Dennis A. Priebat; Dafydd G. Thomas; Jon A. Jacobson; Brian L. Samuels; Robert S. Benjamin; Laurence H. Baker

Purpose: Aggressive fibromatoses (AF; desmoid tumors) are rare clonal neoplastic proliferations of connective tissues that can be locally aggressive despite wide surgical resection and/or radiation therapy. The Sarcoma Alliance for Research through Collaboration (SARC) initiated a prospective phase II trial to investigate the outcome of patients treated with imatinib, a multiple tyrosine kinase inhibitor, in patients with AF, or 1 of 10 sarcoma subtypes. Here, we report specifically on the outcome of patients with AF as well as evaluations undertaken to examine the mechanism of imatinib. Experimental Design: Patients ≥10 years old with desmoid tumors that were not curable by surgical management or in whom curative surgery would lead to undesirable functional impairment were eligible. Imatinib was prescribed at 300 mg twice daily [body surface area (BSA) ≥ 1.5 m2], 200 mg twice daily (BSA = 1.0-1.49 m2), or 100 mg twice daily (BSA < 1.0 m2). Response outcomes at 2 and 4 months were assessed. Tissue specimens were analyzed by immunohistochemistry for expression of cKIT, platelet-derived growth factor receptor α (PDGFRα), PDGFRβ, AKT, PTEN, FKHR, and β-catenin. Tumor DNA was analyzed for PDGFRα exon 18 and APC mutations by allelic discrimination PCR. Results: Fifty-one patients were enrolled. The median number of prior regimens was 1. Kaplan-Meier estimates of 2- and 4-month progression-free survival rates were 94% and 88%, respectively, and 1-year progression-free survival was 66%. Objective response rate was 6% (3 of 51). Expression and polymorphisms of target proteins were identified in tissue samples, but no significant correlation with outcome was observed using the samples available. Conclusion: Imatinib may have a role in the management of unresectable or difficult to resect desmoid tumors. Clin Cancer Res; 16(19); 4884–91. ©2010 AACR.


American Journal of Sports Medicine | 2005

Correlation of Range of Motion and Glenohumeral Translation in Professional Baseball Pitchers

Paul A. Borsa; Kevin E. Wilk; Jon A. Jacobson; Jason S. Scibek; Geoffrey C. Dover; Michael M. Reinold; James R. Andrews

Background Altered mobility patterns in the throwing shoulders of professional baseball pitchers have been reported. Most published reports examining glenohumeral laxity have not used an objective testing device. Objective Quantify and compare glenohumeral translation and rotational range of motion between the throwing and non-throwing shoulders in professional baseball pitchers. Study Design Descriptive laboratory study. Methods Force-displacement and range of motion measures were performed bilaterally on 43 asymptomatic professional baseball pitchers. Ultrasound imaging was used to measure glenohumeral translations under stressed and unstressed conditions. Results No significant difference in translation was found between the throwing and nonthrowing shoulders. For both shoulders, posterior translation (5.38 ± 2.7 mm) was significantly greater (P < .001) than was anterior translation (2.81 ± 1.6 mm). External rotation in the throwing shoulder was significantly greater than that in the nonthrowing shoulder (P < .001), whereas internal rotation in the throwing shoulder was significantly less than that in the nonthrowing shoulder (P < .001). The total arc of rotation for the throwing shoulder was not significantly different than that for the nonthrowing shoulder, and correlation coefficients were poor between rotational and translational range of motion in the throwing shoulder, ranging from r = 0.232 to 0.209 between variables. Conclusion No significant difference in glenohumeral translation exists between the throwing and nonthrowing shoulders in asymptomatic professional baseball pitchers, posterior translation is significantly greater than anterior translation in the throwing shoulders of professional baseball pitchers, and glenohumeral translation is not related to rotational range of motion in the throwing shoulders of professional baseball pitchers. Clinical Relevance Altered mobility patterns in asymptomatic professional baseball pitchers may be due to factors other than capsular adaptive changes.


Radiologic Clinics of North America | 1999

Musculoskeletal sonography and mr imaging : A role for both imaging methods

Jon A. Jacobson

Sonography is currently being applied to many areas of the musculoskeletal system. Although some areas are in the experimental stage, there exist several indications in which sonography can produce results at least equal to what is possible with MR imaging. Examples include evaluation for shoulder and ankle tendon abnormalities; soft tissue infection and joint effusion; soft tissue foreign bodies; soft tissue masses, such as Bakers cyst and wrist ganglion cyst; carpal tunnel syndrome; developmental dysplasia of the hip; and other indications where MR imaging is contraindicated. The role of sonography in evaluation of the musculoskeletal system is evolving. With continued experience and research, newer applications for musculoskeletal sonography will likely become established further defining the roles of sonography and MR imaging in evaluation of the musculoskeletal system.


Journal of Ultrasound in Medicine | 2009

Sonographically Guided Percutaneous Needle Tenotomy for the Treatment of Chronic Tendinosis

Jeffrey A. Housner; Jon A. Jacobson; Roberta Misko

Objective. Initial reports have shown percutaneous sonographically guided needle tenotomy without corticosteroid injection to be effective for the treatment of tennis elbow. The purpose of this study was to determine the effectiveness of this procedure with various tendons throughout the body. Methods. Fourteen tendons in 13 patients were identified as having a greater than 6‐month history of clinical presentation consistent with tendinopathy that had failed treatment with physical therapy. All patients were treated with sonographically guided percutaneous tenotomy using a 22‐gauge needle and a local anesthetic. A visual analog scale (VAS) pain score measurement was obtained before the procedure and at 4‐ and 12‐week follow‐up appointments. All complications were recorded. Results. The 14 tendons in this study included patellar (5), Achilles (4), proximal gluteus medius (1), proximal iliotibial tract (1), proximal hamstring (1), common extensor elbow (1), and proximal rectus femoris (1). The composite VAS score was significantly lower at both 4 weeks (mean ± SEM, 2.4 ± 0.7) and 12 weeks (2.2 ± 0.7) compared with the baseline (5.8 ± 0.6; P < .001). No complications or morbidity occurred. Conclusions. Sonographically guided percutaneous tenotomy of tendinosis was effective in improving patient symptoms without complications. Further investigation with additional patients and comparisons to alternative treatments is needed to validate these preliminary results.


American Journal of Roentgenology | 2006

Sonography of Inguinal Region Hernias

David A. Jamadar; Jon A. Jacobson; Yoav Morag; Gandikota Girish; Farhad S. Ebrahim; Thomas R. Gest; Michael G. Franz

OBJECTIVE The purpose of this article is to describe the anatomy of the inguinal region in a way that is useful for sonographic diagnosis of inguinal region hernias, and to illustrate the sonographic appearance of this anatomy. We show sonographic techniques for evaluating inguinal, femoral, and spigelian hernias and include surgically proven examples. CONCLUSION Understanding healthy inguinal anatomy is essential for diagnosing inguinal region hernias. Sonography can diagnose and differentiate between various inguinal region hernias.


American Journal of Roentgenology | 2008

MDCT and Radiography of Wrist Fractures: Radiographic Sensitivity and Fracture Patterns

Rodney D. Welling; Jon A. Jacobson; David A. Jamadar; Suzanne T. Chong; Elaine M. Caoili; Peter J. L. Jebson

OBJECTIVE The purpose of our study was to determine which wrist fractures are not prospectively diagnosed at radiography using CT as a gold standard and to identify specific fracture patterns. MATERIALS AND METHODS Through a search of radiology records from January 1 to December 31, 2005, 103 consecutive patients were identified as having radiographic and CT examinations of the wrist. After excluding incomplete or nondiagnostic examinations and those with a greater than 6-week interval between imaging studies, the final study group consisted of 61 wrist examinations in 60 patients. Two musculoskeletal radiologists and one emergency radiologist blindly reviewed CT examinations, and each bone (scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate, metacarpals, distal radius, distal ulna) was categorized as normal or fractured, with agreement reached by consensus. Each prospective radiographic report was categorized as either normal or fracture/equivocal for each osseous structure. Results were compared using the chi-square and Fishers exact tests. RESULTS In the proximal carpal row, lunate and triquetrum fractures were often radiographically occult (0% and 20%, respectively, detected at radiography); whereas in the distal carpal row, trapezoid, capitate, and hamate fractures were often occult (0%, 0%, and 40% detected at radiography, respectively). Hamate fractures were significantly associated with metacarpal fractures, and distal radius fractures were associated with scaphoid and ulna fractures. CONCLUSION Thirty percent of wrist fractures were not prospectively diagnosed on radiography, suggesting that CT should be considered after a negative radiographic finding if clinically warranted. The location of a dorsal scaphoid avulsion fracture emphasizes the need for specific radiographic views or cross-sectional imaging for diagnosis.


Journal of Bone and Joint Surgery, American Volume | 2011

Associations of Anatomical Measures from MRI with Radiographically Defined Knee Osteoarthritis Score, Pain, and Physical Functioning

Mary Fran Sowers; Carrie A. Karvonen-Gutierrez; Jon A. Jacobson; Yebin Jiang; Matheos Yosef

BACKGROUND The prevalence of knee osteoarthritis is traditionally based on radiographic findings, but magnetic resonance imaging is now being used to provide better visualization of bone, cartilage, and soft tissues as well as the patellar compartment. The goal of this study was to estimate the prevalences of knee features defined on magnetic resonance imaging in a population and to relate these abnormalities to knee osteoarthritis severity scores based on radiographic findings, physical functioning, and reported knee pain in middle-aged women. METHODS Magnetic resonance images of the knee were evaluated for the location and severity of cartilage defects, bone marrow lesions, osteophytes, subchondral cysts, meniscal and/or ligamentous tears, effusion, and synovitis among 363 middle-aged women (724 knees) from the Michigan Study of Womens Health Across the Nation. These findings were related to Kellgren-Lawrence osteoarthritis severity scores from radiographs, self-reported knee pain, self-reported knee injury, perception of physical functioning, and physical performance measures to assess mobility. Radiographs, physical performance assessment, and interviews were undertaken at the 1996 study baseline and again (with the addition of magnetic resonance imaging assessment) at the follow-up visit during 2007 to 2008. RESULTS The prevalence of moderate-to-severe knee osteoarthritis changed from 3.7% at the baseline assessment to 26.7% at the follow-up visit eleven years later. Full-thickness cartilage defects of the medial, lateral, and patellofemoral compartments were present in 14.5% (105 knees), 4.6% (thirty-three knees), and 26.2% (190 knees), respectively. Synovitis was identified in 24.7% (179) of the knees, and joint effusions were observed in 70% (507 knees); 21.7% (157) of the knees had complex or macerated meniscal tears. Large osteophytes, marked synovitis, macerated meniscal tears, and full-thickness tibial cartilage defects were associated with increased odds of knee pain and with 30% to 40% slower walking and stair-climbing times. CONCLUSIONS Middle-aged women have a high prevalence of moderate-to-severe knee osteoarthritis corroborated by strong associations with cartilage defects, complex and macerated meniscal tears, osteophytes and synovitis, knee pain, and lower mobility levels.

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Yoav Morag

University of Michigan

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Curtis W. Hayes

Virginia Commonwealth University

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Qian Dong

University of Michigan

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