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result(s) for
"Lemmon, Gary"
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The role of glutamine in skeletal muscle ischemia/reperfusion injury in the rat hind limb model
by
Peoples, James
,
Prem, Jeffrey T
,
Lemmon, Gary
in
Animals
,
Antioxidants
,
Biological and medical sciences
1999
Objectives: Ischemia/reperfusion injury is a commonly occurring event with severe pathologic consequences. Reperfusion initiates both the local and systematic damage in part through rapid oxygen generation. The glutathione system is a major mechanism of reducing this oxidative stress. If this system can be maintained or augmented during this stress then less damage may occur. Glutamine provides the source of glutamate to this system and has been shown to preserve total glutathione levels after injury/ischemia to both hepatic and gut models. To test this effect, we looked at glutamine and its role in ischemia/reperfusion injury in a rat hind limb model.
Methods: Fifty male HSD/Holtzman rats weighing 350–400 g were randomized to receive glutamine (3% sol) or normal saline via intraperitoneal injections. The groups were then subjected to 2 hours of ischemia to their hind limbs using the Tourni-Cot method. Animals were then randomized to reperfusion groups of 30 minutes, 2 hours, and 4 hours. Muscle tissue assays were performed for lipid peroxidation (LPO), total glutathione (GSH), and myeloperoxidase (MPO). Peripheral blood was analyzed for creatinephosphokinase levels (CPK).
Results: Animals that received glutamine showed a general trend of less lipid peroxidation products than the normal saline groups. In animals that received glutamine and underwent 2 hours of ischemia and reperfusion times of 0 minutes, 30 minutes, and 2 hours, there were significantly less percent changes in lipid peroxidation products from controls (4.6% vs 48.2%,
P <0.05), (18.9% vs 123%,
P <0.05), (12.6% vs 115%,
P <0.05). A general trend upward was noted in CPK levels in both groups. In animals receiving 2 hours of ischemia and 30 minutes of reperfusion, there was a significantly greater level of creatinephosphokinase (CPK) calculated as percent change from control in the normal saline group as compared with the glutamine group (209.2% vs 92.7%). Myeloperoxidase assay of muscle tissue revealed a progressive increase as the reperfusion times grew. In animals receiving 2 hours of ischemia and 30 minutes of reperfusion, the normal saline group had a significantly larger percent increase from controls than the group that received glutamine (1126.4% vs 108%,
P <0.05). Also, in those animals receiving 4 hours of reperfusion, the normal saline group had a significantly higher percent increase in MPO content than the glutamine group (6245% vs 108%,
P <0.05). Total glutathione levels decreased rapidly as reperfusion occurred in both the normal saline and glutamine groups. No significant difference between the groups was noted.
Conclusions: Total glutathione levels during reperfusion were not significantly different in the groups receiving glutamine versus normal saline. Glutamine may provide an initial protective effect on reperfusion injury after moderate reperfusion times in the hind limb model as defined by CPK and LPO levels. Glutamine may blunt neutrophil recruitment after longer reperfusion times (4 hours) in the ischemic hind limb. Total glutathione levels decreased significantly after moderate levels of ischemia (2 hours) and reperfusion (30 minutes, 2 hours).
Journal Article
Incomplete Caval Protection Following Suprarenal Caval Filter Placement
by
Litscher, Lawrence J.
,
Lemmon, Gary W.
in
Biological and medical sciences
,
Diseases of the cardiovascular system
,
Equipment Design
2000
Inferior vena cava filters are increasingly utilized to prevent pulmonary emboli origi nating from lower extremity, pelvis, or caval thromboses. Unique indications exist for filter placement in the suprarenal portion of the vena cava. The largest reported experi ence in suprarenal position has involved the use of the Greenfield filter. Although unique in design, little differences have been described between the stainless steel and titanium version of this device. The authors present a case report of incomplete caval protection after successful placement of a stainless steel Greenfield filter in the suprarenal cava. Subtle differences between the titanium and the stainless steel Greenfield filter may exist and should be taken into consideration for placement in the suprarenal cava. Physiologic conditions supporting this premise are described. Further investigation between the two filter types appears justified.
Journal Article
Pressure Control Inverse Ratio Ventilation in the Treatment of Adult Respiratory Distress Syndrome in Patients with Blunt Chest Trauma
by
Mccarthy, Mary C.
,
Lemmon, Gary W.
,
Peoples, James B.
in
Adolescent
,
Adult
,
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
1999
The objective of this study was to evaluate the efficacy of pressure control inverse ratio ventilation (PCIRV) in improving oxygenation in trauma patients with adult respiratory distress syndrome (ARDS) and to assess the potential risks associated with this form of treatment. This was a cohort study assessing the trends in hemodynamic and ventilatory parameters after the initiation of PCIRV, conducted at a community Level I trauma center intensive care unit. The study comprised 15 trauma patients developing severe, progressive ARDS [two or more of the following criteria: positive end-expiratory pressure (PEEP) >10 cm H2O; arterial partial pressure of oxygen divided by fraction of inspired oxygen (PaO2:FiO2) ratio <150; and peak inspiratory pressure (PIP) >45 cm H2O]: ten due to blunt chest injuries, three due to sepsis, and two due to fat emboli syndrome. PCIRV was initiated. Main outcome measures were PIP, PEEP (total, auto), oxygen saturation, cardiac index, oxygen delivery, PaO2:FiO2 ratio, compliance, evidence of complications of PCIRV, and mortality. Within 24 hours of conversion to PCIRV, the patients stabilized and the mean PaO2:FiO2 ratio rose from 96.3 ± 57.8 to 146.8 ± 91.1 (P < 0.05) and PIP fell from 47.9 ± 13.8 to 38.8 ± 8.4 cm H2O; auto-PEEP increased from 0.5 ± 1.9 to 7.5 ± 5.6 cm H2O (P < 0.05); oxygen delivery index remained stable (563 ± 152 to 497 ± 175 mL/min/m2); three patients developed evidence of barotrauma, one patient developed critical illness polyneuropathy, and two patients died (13%). PCIRV is an effective salvage mode of ventilation in patients with severe ARDS, but it is not without complications. Auto-PEEP levels and cardiac index should be monitored to ensure tissue oxygen delivery is maintained.
Journal Article
Emergency Thoracotomy: Appropriate Use in the Resuscitation of Trauma Patients
by
Grove, Christopher A.
,
Anderson, Gary
,
Lemmon, Gary
in
Algorithms
,
Clinical Protocols
,
Emergency Treatment - standards
2002
The objective of this study was to evaluate the use of emergency thoracotomy in our institution in an effort to determine whether this procedure is both beneficial and cost effective in blunt and/or penetrating trauma. We conducted a retrospective review of charts and coroner's reports. Our setting was a Level I trauma center in a tertiary-care facility. We examined the cases of trauma patients presenting to the trauma center over a 2-year period. Of 2490 patients who presented to the emergency department over the study period 41 underwent early thoracotomy. Twelve of these were excluded from the study because their cases were not truly emergent. Of the remaining 29 ten were admitted for penetrating injuries and 19 for blunt injuries. The average Injury Severity Scores for penetrating and blunt injuries were 30 and 40 respectively. There were four blunt trauma patients who died in the emergency department, 15 went to the operating room, and five who survived to go to the intensive care unit. All blunt trauma patients requiring emergency thoracotomy died within 9 days of presentation. Of the ten penetrating wound patients two died in the emergency department, four died in the operating room, and four went to the intensive care unit after surgery. One of the four patients who went to the intensive care unit died approximately 6 days after injury. The other three patients survived and are now living normal productive lives. All survivors of penetrating trauma who required emergency thoracotomy had their procedure performed in the operating room. Overall survival rates for penetrating and blunt trauma were 30 and 0 per cent respectively. Pericardial tamponade was found in 50 per cent of the penetrating trauma patients (two of the three survivors) and four of 19 of the blunt trauma patients. This reinforces the importance of a prompt pericardiotomy upon opening the chest. At our institution the algorithm for emergency thoracotomy is liberal and is not cost effective for blunt trauma. We need to re-evaluate our decision-making process concerning the use of emergency thoracotomy especially in the blunt trauma patient. The review also shows the importance of pericardiotomy when performing an emergency thoracotomy.
Journal Article
Traditional Criteria for Observation of Splenic Trauma Should be Challenged
by
Mccarthy, Mary C.
,
Barney, Linda M.
,
Dunn, Margaret M.
in
Biological and medical sciences
,
Blood Pressure
,
Glasgow Coma Scale
1999
Age less than 55 years, normal Glasgow Coma Score (GCS), and absence of hypotension are traditional criteria for the selection of adult patients with blunt splenic trauma for observation. The objective of this study is to challenge these criteria. Two hundred twelve patients who presented with blunt splenic injury between 1992 and 1997 were identified from the Trauma Registry at our Level I trauma center. The patients were divided into three groups: 100 patients (47%) were observed, 108 (51%) underwent immediate splenorrhaphy or splenectomy, and 4 (2%) failed observation. The three groups were compared by participants’ ages, GCSs, and histories of hypotension. No statistical differences were noted between the successfully observed patients and those requiring immediate surgery with respect to these criteria. Of the 4 patients who failed observation, all were younger than 55 years, all had a GCS >12, and all were normotensive. Our findings suggest that traditional criteria used to select patients for splenic trauma observation are not absolute indicators and should be liberalized: patients can be successfully observed despite having criteria that, in the past, would have led to immediate operative intervention.
Journal Article
Emergency thoracotomy: Appropriate use in the resuscitation of trauma patients. Discussion
by
ANDERSON, Gary
,
MCCARTHY, Mary
,
LLOYD, Larry R
in
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
,
Biological and medical sciences
,
Critical care
2002
The objective of this study was to evaluate the use of emergency thoracotomy in our institution in an effort to determine whether this procedure is both beneficial and cost effective in blunt and/or penetrating trauma. We conducted a retrospective review of charts and coroner's reports. Our setting was a Level I trauma center in a tertiary-care facility. We examined the cases of trauma patients presenting to the trauma center over a 2-year period. Of 2490 patients who presented to the emergency department over the study period 41 underwent early thoracotomy. Twelve of these were excluded from the study because their cases were not truly emergent. Of the remaining 29 ten were admitted for penetrating injuries and 19 for blunt injuries. The average Injury Severity Scores for penetrating and blunt injuries were 30 and 40 respectively. There were four blunt trauma patients who died in the emergency department, 15 went to the operating room, and five who survived to go to the intensive care unit. All blunt trauma patients requiring emergency thoracotomy died within 9 days of presentation. Of the ten penetrating wound patients two died in the emergency department, four died in the operating room, and four went to the intensive care unit after surgery. One of the four patients who went to the intensive care unit died approximately 6 days after injury. The other three patients survived and are now living normal productive lives. All survivors of penetrating trauma who required emergency thoracotomy had their procedure performed in the operating room. Overall survival rates for penetrating and blunt trauma were 30 and 0 per cent respectively. Pericardial tamponade was found in 50 per cent of the penetrating trauma patients (two of the three survivors) and four of 19 of the blunt trauma patients. This reinforces the importance of a prompt pericardiotomy upon opening the chest. At our institution the algorithm for emergency thoracotomy is liberal and is not cost effective for blunt trauma. We need to re-evaluate our decision-making process concerning the use of emergency thoracotomy especially in the blunt trauma patient. The review also shows the importance of pericardiotomy when performing an emergency thoracotomy.
Conference Proceeding
Improved selection criteria for ordering stat venous ultrasounds from the emergency department
1998
Background: The accuracy and convenience of venous ultrasound (VU) to exclude deep vein thrombosis (DVT) has led to indiscriminate use and low positive yield rates.
Methods: A total of 256 patients were referred from our emergency department (ED) for stat VU during a 2-year period (1995 to 1996). The VUs were interpreted as normal in 198 (77%). Positive findings were discovered in 58 (23%), with DVT accounting for 43 (17%). Retrospective multivariant analysis was used to identify predictive indicators.
Results: Unilateral leg swelling/edema identified 36 of 40 (90%) patients with DVT and 8 of 10 (80%) with other thrombotic disorders (saphenous and/or chronic venous thrombosis). A history of leg pain with prior DVT or recent trauma ≤3 days’ duration increased DVT duration to 98% (39 of 40). Using these criteria, a 47% charge reduction would have been recognized.
Conclusions: Improving ED screening criteria can safely increase yield rate and reduce charges with minimal loss of VU sensitivity.
Journal Article
Political Promotion, CEO Incentives, and the Relationship Between Pay and Performance
by
Lemmon, Michael
,
Tian, Gary
,
Pan, Xiaofei
in
CEO compensation
,
Chief executive officers
,
Chief executives
2019
Both theory and empirical evidence suggest that managers’ career concerns can serve as an important source of implicit economic incentives. We examine how incentives for political promotion are related to compensation policy and firm performance in Chinese state-owned enterprises. We find that the likelihood that the CEO receives a political promotion is positively related to firm performance. We also find that CEOs with a higher likelihood of political promotion have lower pay levels and lower pay–performance sensitivity. Overall, the evidence suggests that competition in the political job market helps mitigate weak monetary incentives for CEOs in China.
Data are available at
https://doi.org/10.1287/mnsc.2017.2966
.
This paper was accepted by Lauren Cohen, finance.
Journal Article
Political Promotion, CEO Incentives, and the Relationship Between Pay and Performance
by
Tiane, Gary
,
Lemmon, Michael
,
Pan, Xiaofei
in
Chief executive officers
,
Compensation and benefits
,
Compensation management
2019
Both theory and empirical evidence suggest that managers' career concerns can serve as an important source of implicit economic incentives. We examine how incentives for political promotion are related to compensation policy and firm performance in Chinese state-owned enterprises. We find that the likelihood that the CEO receives a political promotion is positively related to firm performance. We also find that CEOs with a higher likelihood of political promotion have lower pay levels and lower pay-performance sensitivity. Overall, the evidence suggests that competition in the political job market helps mitigate weak monetary incentives for CEOs in China.
Journal Article
Phosphorylation-Dependent Regulation of Axon Fasciculation
1991
Axons often grow along other axons to produce bundles called fascicles, and a number of cell adhesion molecules (CAMs) found on axon surfaces contribute to this process. The surprising observation that Fab fragments against individual CAMs can completely block fascicle formation suggests that the different axon-associated CAMs are functionally linked. The present studies investigate whether such a linkage might reflect intracellular regulatory mechanisms. Results obtained with chicken retinal explants in culture indicate that fasciculation is highly sensitive to cytoplasmic protein phosphorylation by means of a mechanism that does not alter levels of CAM expression. Moreover, the potent effect of individual Fabs on fasciculation disappears with enhanced phosphorylation. These observations suggest that growing axons possess a general regulatory process for the multiple CAMs that participate in fasciculation.
Journal Article