James Paci - Academia.edu (original) (raw)

Papers by James Paci

The Journal of Cell Biology, 2001

Caveolin-1 is normally localized in plasma membrane caveolae and the Golgi apparatus in mammalian... more Caveolin-1 is normally localized in plasma membrane caveolae and the Golgi apparatus in mammalian cells. We found three treatments that redirected the protein to lipid storage droplets, identified by staining with the lipophilic dye Nile red and the marker protein ADRP. Caveolin-1 was targeted to the droplets when linked to the ER-retrieval sequence, KKSL, generating Cav-KKSL. Cav-⌬ N2, an internal deletion mutant, also accumulated in the droplets, as well as in a Golgi-like structure. Third, incubation of cells with brefeldin A caused caveolin-1 to accumulate in the droplets. This localization persisted after drug washout, showing that caveolin-1 was transported out of the droplets slowly or not at all. Some overexpressed cave-olin-2 was also present in lipid droplets. Experimental reduction of cellular cholesteryl ester by 80% did not prevent targeting of Cav-KKSL to the droplets. Cav-KKSL expression did not grossly alter cellular triacylglyceride or cholesteryl levels, although droplet morphology was affected in some cells. These data suggest that accumulation of caveolin-1 to unusually high levels in the ER causes targeting to lipid droplets, and that mechanisms must exist to ensure the rapid exit of newly synthesized caveolin-1 from the ER to avoid this fate.

The American Journal of Sports Medicine, 2013

An olecranon stress fracture is a rare injury associated with valgus extension overload in baseba... more An olecranon stress fracture is a rare injury associated with valgus extension overload in baseball players. No long-term outcomes studies have been published documenting the results of surgical fixation of olecranon stress fractures with or without concomitant injuries in baseball players. Open reduction and internal fixation (ORIF) of an olecranon stress fracture will reliably produce bony union and allow a successful return to the previous level of activity in competitive baseball players. Case series; Level of evidence, 4. Twenty-five patients treated with ORIF for an olecranon stress fracture at least 2 years earlier (range, 2-10.14 years) were retrospectively contacted to complete a telephone survey; 18 of 25 (72%) patients responded. Data were collected to determine the return to play rate, level of arm pain, and overall arm function. All 18 stress fractures went on to successful union; 17 of 18 (94%) athletes returned to baseball at or above their previous level. Average return to play time was 29 weeks. The numeric analog pain score was 0.2 at rest and 0.3 when throwing at the time of follow-up, at an average 6.2 years (range, 2.0-10.14 years) after surgery. The average score at follow-up on the disabilities of the arm, shoulder and hand outcome measure-shortened version (QuickDASH) was 4.1 (range, 0-27.3). Ten (56%) patients required 13 additional future surgeries on their throwing arm; 7 surgeries in 6 (33%) patients were not related to the index surgery. Six of 18 (33%) patients underwent hardware removal, with 2 (11%) for infection. Open reduction and internal fixation of olecranon stress fractures in competitive baseball players has a high rate of success in returning players to or above their former level of play and allows for good elbow function at an average of 6.2 years postoperatively. However, these patients are at high risk for additional future surgeries on their throwing arm.

The American Journal of Sports Medicine, 2009

The anterior intermeniscal ligament of the knee is at risk during knee arthroscopy, anterior cruc... more The anterior intermeniscal ligament of the knee is at risk during knee arthroscopy, anterior cruciate ligament reconstruction, and tibial nail insertion. Release of the anterior intermeniscal ligament, in knees with type I ligaments, will result in altered contact pressures in the medial compartment. Controlled laboratory study. Five fresh-frozen human cadaveric knees with intact type I anterior intermeniscal ligaments were chosen for testing in a modified MTS machine from 0 degrees to 60 degrees of flexion under 2 conditions: (1) intact and (2) after sharp sectioning of the anterior intermeniscal ligament. Measurements were made using inframeniscal contact pressure sensors covering the medial compartment. Poststudy analysis was done in 10 degrees increments between 0 degrees and 60 degrees of flexion, looking at peak contact pressure and the amount of contact area seeing pressure. Sectioning of the anterior intermeniscal ligament caused a statistically significant increase in the peak pressure at 20 degrees , 30 degrees , 40 degrees , and 50 degrees of knee flexion. The largest change occurred at 40 degrees of knee flexion, when the peak pressure increased by 27.5% (3.68 MPa to 4.69 MPa). Contact area decreased, although this difference was not statistically significant. Release of the anterior intermeniscal ligament results in increased peak contact pressures in the medial compartment of the knee. Care should be taken to avoid sacrifice of this ligament during surgery.

The American Journal of Sports Medicine, 2010

Infection after anterior cruciate ligament reconstruction is a rare and potentially devastating c... more Infection after anterior cruciate ligament reconstruction is a rare and potentially devastating complication. No normative data have been reported for knee aspiration after anterior cruciate ligament reconstruction in the early postoperative period. Determining normative laboratory data from a retrospective review of noninfected early postoperative anterior cruciate ligament reconstruction knee effusions will allow for the calculation of an aspirate white blood cell (WBC) threshold value indicative of infection. Case series (diagnosis); Level of evidence, 4. A 2-year retrospective chart review of 151 anterior cruciate ligament reconstruction patients was performed. Thirty-one noninfected patients meeting the inclusion and exclusion criteria and 1 infected patient had laboratory data collected, including peripheral blood and knee effusion aspirate analyses. Laboratory data from pertinent published studies of infected knees after anterior cruciate ligament reconstruction were combined with the data of our 1 infected patient, establishing a historical control group. Data were analyzed and results were then compared. Infected aspirate WBC threshold value statistics were then calculated. Analysis of noninfected knee effusion aspirates revealed a mean WBC count of 9600/uL (standard deviation [SD], 15 200), and a mean of 66% polymorphonuclear (PMN) cells (SD, 34). Aspirate WBC 98% confidence interval (CI) was 2800/uL to 16 200/uL, and the 98% CI for PMN cells was 58% to 84%. Aspirate WBC count >16 200/uL is 86% sensitive, 92% specific, and has a positive likelihood ratio of 10.4 as an indicator of infection. Benign effusion after anterior cruciate ligament reconstruction is common and is associated with elevated inflammatory markers. When concerned, knee aspiration after anterior cruciate ligament surgery gives the highest yield to differentiate between a painful effusion and a septic knee in the early postoperative period while awaiting definitive culture results. The authors report confidence intervals defining the range of cell count variables for noninfected patients requiring aspiration, specifically WBC and PMN, and suggest a WBC threshold value of >16 200/uL be used as an indicator of infection. On the basis of comparison with historical control data, the authors believe these data are significant and will be reliable for clinical use.

Arthroscopy techniques, 2014

Distal triceps rupture is a rare injury causing significant disability. Several techniques for tr... more Distal triceps rupture is a rare injury causing significant disability. Several techniques for treating distal triceps ruptures have been described using bone tunnels or suture anchors. More recent techniques have focused on re-creating the anatomic footprint of the distal triceps tendon. However, the increasing numbers of anchors used increase the risk to the articular surface, and all earlier techniques require knot tying and bulky knots beneath the thin posterior elbow soft-tissue envelope. We describe a technique combining the use of bone tunnels and a single suture anchor to create a knotless anatomic footprint repair of the distal triceps. By using this technique, we are able to create a tension-band construct that self-reinforces the anatomic repair and is very low profile while significantly decreasing risk to the articular surface.

The Journal of Cell Biology, 2001

Caveolin-1 is normally localized in plasma membrane caveolae and the Golgi apparatus in mammalian... more Caveolin-1 is normally localized in plasma membrane caveolae and the Golgi apparatus in mammalian cells. We found three treatments that redirected the protein to lipid storage droplets, identified by staining with the lipophilic dye Nile red and the marker protein ADRP. Caveolin-1 was targeted to the droplets when linked to the ER-retrieval sequence, KKSL, generating Cav-KKSL. Cav-⌬ N2, an internal deletion mutant, also accumulated in the droplets, as well as in a Golgi-like structure. Third, incubation of cells with brefeldin A caused caveolin-1 to accumulate in the droplets. This localization persisted after drug washout, showing that caveolin-1 was transported out of the droplets slowly or not at all. Some overexpressed cave-olin-2 was also present in lipid droplets. Experimental reduction of cellular cholesteryl ester by 80% did not prevent targeting of Cav-KKSL to the droplets. Cav-KKSL expression did not grossly alter cellular triacylglyceride or cholesteryl levels, although droplet morphology was affected in some cells. These data suggest that accumulation of caveolin-1 to unusually high levels in the ER causes targeting to lipid droplets, and that mechanisms must exist to ensure the rapid exit of newly synthesized caveolin-1 from the ER to avoid this fate.

The American Journal of Sports Medicine, 2013

An olecranon stress fracture is a rare injury associated with valgus extension overload in baseba... more An olecranon stress fracture is a rare injury associated with valgus extension overload in baseball players. No long-term outcomes studies have been published documenting the results of surgical fixation of olecranon stress fractures with or without concomitant injuries in baseball players. Open reduction and internal fixation (ORIF) of an olecranon stress fracture will reliably produce bony union and allow a successful return to the previous level of activity in competitive baseball players. Case series; Level of evidence, 4. Twenty-five patients treated with ORIF for an olecranon stress fracture at least 2 years earlier (range, 2-10.14 years) were retrospectively contacted to complete a telephone survey; 18 of 25 (72%) patients responded. Data were collected to determine the return to play rate, level of arm pain, and overall arm function. All 18 stress fractures went on to successful union; 17 of 18 (94%) athletes returned to baseball at or above their previous level. Average return to play time was 29 weeks. The numeric analog pain score was 0.2 at rest and 0.3 when throwing at the time of follow-up, at an average 6.2 years (range, 2.0-10.14 years) after surgery. The average score at follow-up on the disabilities of the arm, shoulder and hand outcome measure-shortened version (QuickDASH) was 4.1 (range, 0-27.3). Ten (56%) patients required 13 additional future surgeries on their throwing arm; 7 surgeries in 6 (33%) patients were not related to the index surgery. Six of 18 (33%) patients underwent hardware removal, with 2 (11%) for infection. Open reduction and internal fixation of olecranon stress fractures in competitive baseball players has a high rate of success in returning players to or above their former level of play and allows for good elbow function at an average of 6.2 years postoperatively. However, these patients are at high risk for additional future surgeries on their throwing arm.

The American Journal of Sports Medicine, 2009

The anterior intermeniscal ligament of the knee is at risk during knee arthroscopy, anterior cruc... more The anterior intermeniscal ligament of the knee is at risk during knee arthroscopy, anterior cruciate ligament reconstruction, and tibial nail insertion. Release of the anterior intermeniscal ligament, in knees with type I ligaments, will result in altered contact pressures in the medial compartment. Controlled laboratory study. Five fresh-frozen human cadaveric knees with intact type I anterior intermeniscal ligaments were chosen for testing in a modified MTS machine from 0 degrees to 60 degrees of flexion under 2 conditions: (1) intact and (2) after sharp sectioning of the anterior intermeniscal ligament. Measurements were made using inframeniscal contact pressure sensors covering the medial compartment. Poststudy analysis was done in 10 degrees increments between 0 degrees and 60 degrees of flexion, looking at peak contact pressure and the amount of contact area seeing pressure. Sectioning of the anterior intermeniscal ligament caused a statistically significant increase in the peak pressure at 20 degrees , 30 degrees , 40 degrees , and 50 degrees of knee flexion. The largest change occurred at 40 degrees of knee flexion, when the peak pressure increased by 27.5% (3.68 MPa to 4.69 MPa). Contact area decreased, although this difference was not statistically significant. Release of the anterior intermeniscal ligament results in increased peak contact pressures in the medial compartment of the knee. Care should be taken to avoid sacrifice of this ligament during surgery.

The American Journal of Sports Medicine, 2010

Infection after anterior cruciate ligament reconstruction is a rare and potentially devastating c... more Infection after anterior cruciate ligament reconstruction is a rare and potentially devastating complication. No normative data have been reported for knee aspiration after anterior cruciate ligament reconstruction in the early postoperative period. Determining normative laboratory data from a retrospective review of noninfected early postoperative anterior cruciate ligament reconstruction knee effusions will allow for the calculation of an aspirate white blood cell (WBC) threshold value indicative of infection. Case series (diagnosis); Level of evidence, 4. A 2-year retrospective chart review of 151 anterior cruciate ligament reconstruction patients was performed. Thirty-one noninfected patients meeting the inclusion and exclusion criteria and 1 infected patient had laboratory data collected, including peripheral blood and knee effusion aspirate analyses. Laboratory data from pertinent published studies of infected knees after anterior cruciate ligament reconstruction were combined with the data of our 1 infected patient, establishing a historical control group. Data were analyzed and results were then compared. Infected aspirate WBC threshold value statistics were then calculated. Analysis of noninfected knee effusion aspirates revealed a mean WBC count of 9600/uL (standard deviation [SD], 15 200), and a mean of 66% polymorphonuclear (PMN) cells (SD, 34). Aspirate WBC 98% confidence interval (CI) was 2800/uL to 16 200/uL, and the 98% CI for PMN cells was 58% to 84%. Aspirate WBC count >16 200/uL is 86% sensitive, 92% specific, and has a positive likelihood ratio of 10.4 as an indicator of infection. Benign effusion after anterior cruciate ligament reconstruction is common and is associated with elevated inflammatory markers. When concerned, knee aspiration after anterior cruciate ligament surgery gives the highest yield to differentiate between a painful effusion and a septic knee in the early postoperative period while awaiting definitive culture results. The authors report confidence intervals defining the range of cell count variables for noninfected patients requiring aspiration, specifically WBC and PMN, and suggest a WBC threshold value of >16 200/uL be used as an indicator of infection. On the basis of comparison with historical control data, the authors believe these data are significant and will be reliable for clinical use.

Arthroscopy techniques, 2014

Distal triceps rupture is a rare injury causing significant disability. Several techniques for tr... more Distal triceps rupture is a rare injury causing significant disability. Several techniques for treating distal triceps ruptures have been described using bone tunnels or suture anchors. More recent techniques have focused on re-creating the anatomic footprint of the distal triceps tendon. However, the increasing numbers of anchors used increase the risk to the articular surface, and all earlier techniques require knot tying and bulky knots beneath the thin posterior elbow soft-tissue envelope. We describe a technique combining the use of bone tunnels and a single suture anchor to create a knotless anatomic footprint repair of the distal triceps. By using this technique, we are able to create a tension-band construct that self-reinforces the anatomic repair and is very low profile while significantly decreasing risk to the articular surface.