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Dive into the research topics where H. Leon Pachter is active.

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Featured researches published by H. Leon Pachter.


Annals of Surgery | 1992

Significant trends in the treatment of hepatic trauma. Experience with 411 injuries.

H. Leon Pachter; Frank C. Spencer; Steven R. Hofstetter; Howard Liang; Gene F. Coppa

Several significant advances in the treatment of hepatic injuries have evolved over the past decade. These trends have been incorporated into the overall treatment strategy of hepatic injuries and are reflected in experiences with 411 consecutive patients. Two hundred fifty-eight patients (63%) with minor injuries (grades I to II) were treated by simple suture or hemostatic agents with a mortality rate of 6%. One hundred twenty-eight patients (31%) sustained complex hepatic injuries (grades III to V). One hundred seven patients (83.5%) with grades III or IV injury underwent portal triad occlusion and finger fracture of hepatic parenchyma alone. Seventy-three surviving patients (73%) required portal triad occlusion, with ischemia times varying from 10 to 75 minutes (mean, 30 minutes). The mortality rate in this group was 6.5% (seven patients) and was accompanied by a morbidity rate of 15%. Fourteen patients (11%) with grade V injury (retrohepatic cava or hepatic veins) were managed by prolonged protal triad occlusion (mean cross-clamp time, 46 minutes) and extensive finger fracture to the site of injury. In four of these patients an atrial caval shunt was additionally used. Two of these patients survived, whereas six of the 10 patients managed without a shunt survived, for an overall mortality rate of 43%. Over the past 4 years, six patients (4.7%) with ongoing coagulopathies were managed by packing and planned re-exploration, with four patients (67%) surviving and one (25%) developing an intra-abdominal abscess. One additional patient (0.8%) was managed by resectional debridement alone and survived. During the past 5 years, 25 hemodynamically stable and alert adult patients (6%) sustaining blunt trauma were evaluated by computed tomography scan and found to have grade I to III injuries. All were managed nonoperatively with uniform success. The combination of portal triad occlusion (up to 75 minutes), finger fracture technique, and the use of a viable omental pack is a safe, reliable, and effective method of managing complex hepatic injuries (grade III to IV). Juxtahepatic venous injuries continue to carry a prohibitive mortality rate, but nonshunting approaches seem to result in the lowest cumulative mortality rate. Packing and planned reexploration has a definitive life-saving role when used adjunctively in the presence of a coagulopathy. Nonoperative management of select hemodynamically stable adult patients, identified by serial computed tomography scans after sustaining blunt trauma is highly successful (95-97%).


Journal of Clinical Investigation | 2009

In liver fibrosis, dendritic cells govern hepatic inflammation in mice via TNF-α

Michael K. Connolly; Andrea S. Bedrosian; Jon Mallen-St. Clair; Aaron Mitchell; Junaid Ibrahim; Andrea Stroud; H. Leon Pachter; Dafna Bar-Sagi; Alan B. Frey; George Miller

Hepatic fibrosis occurs during most chronic liver diseases and is driven by inflammatory responses to injured tissue. Because DCs are central to modulating liver immunity, we postulated that altered DC function contributes to immunologic changes in hepatic fibrosis and affects the pathologic inflammatory milieu within the fibrotic liver. Using mouse models, we determined the contribution of DCs to altered hepatic immunity in fibrosis and investigated the role of DCs in modulating the inflammatory environment within the fibrotic liver. We found that DC depletion completely abrogated the elevated levels of many inflammatory mediators that are produced in the fibrotic liver. DCs represented approximately 25% of the fibrotic hepatic leukocytes and showed an elevated CD11b+CD8- fraction, a lower B220+ plasmacytoid fraction, and increased expression of MHC II and CD40. Moreover, after liver injury, DCs gained a marked capacity to induce hepatic stellate cells, NK cells, and T cells to mediate inflammation, proliferation, and production of potent immune responses. The proinflammatory and immunogenic effects of fibrotic DCs were contingent on their production of TNF-alpha. Therefore, modulating DC function may be an attractive approach to experimental therapeutics in fibro-inflammatory liver disease.


American Journal of Surgery | 1995

The current status of nonoperative management of adult blunt hepatic injuries

H. Leon Pachter; Steven R. Hofstetter

This review of 14 recent publications encompassing 495 patients highlights the current role of the nonoperative management of adult blunt hepatic injuries. When careful inclusion criteria were met, the most important of which is hemodynamic stability, a 94% success rate was achieved, clearly attesting to the safety and efficacy of this approach. A 0% liver-related mortality in these 495 patients was achieved, and there were no documented missed enteric injuries. Delayed hemorrhage that led to laparotomy occurred in 2.8% of patients. The mean length of hospital stay was 13 days, and the mean transfusion requirement was 1.9 units of blood per patient. Computed axial tomography scanning was essential and played an integral role in delineating the extent of the injury, identifying other intra-abdominal injuries that would mandate immediate laparotomy, and following the progress of injury resolution. Overall, 34% of blunt liver injuries were managed nonoperatively. As of 1993, however, available data confirms that 51% of adult reported blunt hepatic injuries have been treated nonoperatively. Rigid adherence to the described guidelines may allow the majority of blunt hepatic injuries to be treated nonoperatively. It should be stressed, however, that this method of patient management should only be undertaken at institutions where the appropriate resources necessary to deal with this patient population are readily available.


American Journal of Surgery | 1995

Pitfalls in the Diagnosis of Blunt Diaphragmatic Injury

Amber A. Guth; H. Leon Pachter; Unsup Kim

BACKGROUND Severe blunt trauma to the torso can result in diaphragmatic disruption. Prompt recognition of this potentially life-threatening injury is difficult when the initial chest roentgenogram is unrevealing and immediate thoracotomy or celiotomy is not performed. This retrospective study was undertaken to: (1) determine the incidence of missed diaphragmatic injuries on initial evaluation; (2) identify factors contributing to diagnostic delays; and (3) formulate a diagnostic approach that reliably detects diaphragmatic rupture following blunt trauma. METHODS Retrospective review of hospital records and radiographs from our 18-year experience with blunt diaphragmatic injuries. RESULTS Seven of 57 (12%) blunt diaphragmatic injuries were missed on initial evaluation. Recognition followed 2 days to 3 months later. Two (4%) isolated left-sided injuries initially presented with normal chest roentgenograms. Five patients (9%) (4 with right-sided ruptures) had abnormalities on chest roentgenogram or computed tomography (CT) initially attributed to chest trauma. They were diagnosed by radionuclide, ultrasound, or CT investigations of hemothorax, pulmonary sepsis, and right upper quadrant pain; and, in 1 case, at thoracotomy for a persistent right hemothorax. In the remaining 50 patients (88%), the diagnosis was established within 24 hours. In 21 (42%) of these, the problem was initially recognized at the time of celiotomy for accompanying injuries. CONCLUSIONS Blunt diaphragmatic injuries are easily missed in the absence of other indications for immediate surgery, since radiologic abnormalities of the diaphragm--particularly those involving the right hemidiaphragm--are often interpreted as thoracic trauma. In this setting, a high index of suspicion coupled with selective use of radionuclide scanning, ultrasound, and CT or magnetic resonance imaging is necessary for early detection of this uncommon injury.


American Journal of Surgery | 2000

Domestic violence and the trauma surgeon

Amber A. Guth; H. Leon Pachter

BACKGROUND Domestic violence has become increasingly recognized as a public health problem, and was declared a national epidemic by C. Everett Koop in 1992. In the United States, 1 to million women yearly suffer injuries due to domestic violence, and 30% to 50% of female homicides are committed by a present or former partner. The majority of these murder victims had either been seen in emergency rooms for prior domestic violence-related injuries, or had reported these injuries to the police. It is estimated that 50% of all acute injuries and 21% of all injuries in women requiring urgent surgery ar the result of partner abuse. DATA SOURCE Medline and current literature review. CONCLUSIONS Health care professionals in the emergency room are an important contact with the victims of domestic violence, and timely identification and intervention can save lives. Overall, upwards of 35% of all emergency room visits by women are the result of domestic violence, whether due to acute injury, problems during pregnancy, or stress-related complaints. Unfortunately, domestic abuse is infrequently disclosed voluntarily by the patient, and often overlooked by the treating physician. Thus, the purpose of this review is to familiarize surgeons with the presentation and management of victims of this hidden epidemic.


Annals of Surgery | 1994

Autologous splenic transplantation for splenic trauma.

Peter W.T. Pisters; H. Leon Pachter

ObjectiveThe authors reviewed the experimental evidence, surgical technique, complications, and results of clinical trials evaluating the role of autologous splenic transplantation for splenic trauma. Summary Background DataSplenorrhaphy and nonoperative management of splenic injuries have now become routine aspects in the management of splenic trauma. Unfortunately, not all splenic injuries are readily amenable to conventional spleen-conserving approaches. Heterotopic splenic autotransplantation has been advocated for patients with severe grade IV and V injuries that would otherwise mandate splenectomy. For this subset of patients, splenic salvage by autotransplantation would theoretically preserve the critical role the spleen plays in the hosts defense against Infection. MethodsThe relevant literature relating to experimental or clinical aspects of splenic autotransplantation was identified and reviewed. Data are presented on the experimental evaluation of autogenous splenic transplantation, methods and complications of autotransplantation, choice of anatomic site and autograft size, and results of clinical trials in humans. ResultsThe most commonly used technique of autotransplantation In humans involves implanting tissue homogenates or sections of splenic parenchyma into pouches created in the gastrocolic omentum. Most authors have observed evidence of splenic function with normalization of postsptenectomy thrombocytosis, immunoglobulin-M levels, and peripheral blood smears. Some degree of immune function of transplanted grafts has been demonstrated with in vivo assays, but the ful extent of immunoprotection provided by human splenic autotransplants is currently unknown. ConclusionsMultiple human and animal studies have established that splenic autotransplantation is a relatively safe and easily performed procedure that results in the return of some hematologic and immunologic parameters to baseline levels. Some aspects of reticuloendothelial function are also preserved. Whether this translates into a real reduction in the morbidity or mortality rates from overwhelming bacterial Infection is unknown and requires further investigation.


Journal of The American College of Surgeons | 2001

Multiinstitutional Experience With the Management of Superior Mesenteric Artery Injuries.

Juan A. Asensio; L. D. Britt; Anthony P. Borzotta; Andrew B. Peitzman; Frank B. Miller; Robert C. Mackersie; Michael D. Pasquale; H. Leon Pachter; David B. Hoyt; Jorge L. Rodriguez; Robert E. Falcone; Kimberly A. Davis; John T. Anderson; Jameel Ali; Linda Chan

BACKGROUND Superior mesenteric artery (SMA) injuries are rare and often lethal injuries incurring very high morbidity and mortality. The purposes of this study are to review a multiinstitutional experience with these injuries; to analyze Fullens classification based on anatomic zone and ischemia grade for its predictive value; to correlate the American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) for abdominal vascular injury with mortality; and to identify independent risk factors predictive of mortality, describing current trends for the management of this injury in America. DESIGN We performed a retrospective multiinstitutional study of patients sustaining SMA injuries involving 34 trauma centers in the US over 10 years. Outcomes variables, both continuous and dichotomous, were analyzed initially with univariate methods. For the subsequent multivariate analysis, stepwise logistic regression was used to identify a set of risk factors significantly associated with mortality. RESULTS There were 250 patients enrolled, with a mean Revised Trauma Score (RTS) of 6.44 and a mean Injury Severity Score (ISS) of 25. Surgical management consisted of ligation in 175 of 244 patients (72%), primary [corrected] repair in 53 of 244 patients (22%), autogenous grafts were used in 10 of 244 (4%), and prosthetic grafts of PTFE in 6 of 244 patients (2%). Overall mortality was 97 of 250 patients (39%). Mortality versus Fullens zones: zone I, 39 of 51 (76.5%); zone II, 15 of 34 (44.1%); zone III, 11 of 40 (27.5%); and zone IV, 25 of 108 (23.1%). Mortality versus Fullens ischemia grade: grade 1, 22 of 34 (64.7%). Mortality versus AAST-OIS for abdominal vascular injury: grade I, 9 of 55 (16.4%); grade II, 13 of 51 (25.5%); grade III, 8 of 20 (40%); grade IV, 37 of 69 (53.6%); and grade V, 17 of 19 (89.5%). Logistic regression analysis identified as independent risk factors for mortality the following: transfusion of greater than 10 units of packed RBCs, intraoperative acidosis, dysrhythmias, injury to Fullens zone I or II, and multisystem organ failure. CONCLUSION SMA injuries are highly lethal. Fullens anatomic zones, ischemia grade, and AAST-OIS abdominal vascular injuries correlate well with mortality. Injuries to Fullens zones I and II, Fullens maximal ischemia grade, and AAST-OIS injury grades IV and V, high-intraoperative transfusion requirements, and presence of acidosis and disrhythmias are significant predictors of mortality. All of these predictive factors for mortality must be taken into account in the surgical management of these injuries.


Journal of Leukocyte Biology | 2010

Distinct populations of metastases‐enabling myeloid cells expand in the liver of mice harboring invasive and preinvasive intra‐abdominal tumor

Michael K. Connolly; Jon Mallen-St. Clair; Andrea S. Bedrosian; Ashim Malhotra; Valery Vera; Junaid Ibrahim; Justin R. Henning; H. Leon Pachter; Dafna Bar-Sagi; Alan B. Frey; George Miller

The liver is the most common site of adenocarcinoma metastases, even in patients who initially present with early disease. We postulated that immune‐suppressive cells in the liver of tumor‐bearing hosts inhibit anti‐tumor T cells, thereby accelerating the growth of liver metastases. Using models of early preinvasive pancreatic neoplasia and advanced colorectal cancer, aims of this study were to determine immune phenotype, stimulus for recruitment, inhibitory effects, and tumor‐enabling function of immune‐suppressive cells in the liver of tumor‐bearing hosts. We found that in mice with intra‐abdominal malignancies, two distinct CD11b+Gr1+ populations with divergent phenotypic and functional properties accumulate in the liver, becoming the dominant hepatic leukocytes. Their expansion is contingent on tumor expression of KC. These cells are distinct from CD11b+Gr1+ populations in other tissues of tumor‐bearing hosts in terms of cellular phenotype and cytokine and chemokine profile. Liver CD11b+Gr1+ cells are highly suppressive of T cell activation, proliferation, and cytotoxicity and induce the development of Tregs. Moreover, liver myeloid‐derived suppressor cells accelerate the development of hepatic metastases by inactivation of cytotoxic T cells. These findings may explain the propensity of patients with intra‐abdominal cancers to develop liver metastases and suggest a promising target for experimental therapeutics.


Journal of Trauma-injury Infection and Critical Care | 1990

The morbidity and financial impact of colostomy closure in trauma patients.

H. Leon Pachter; Jamal Hoballah; Thomas A. Corcoran; Steven R. Hofstetter

During a 10-year period, 87 patients who had undergone elective colostomy closure at Bellevue Hospital were retrospectively reviewed in order to evaluate the morbidity of colostomy closure after traumatic injury and its financial impact. Sixty-two per cent of the colostomies were in the left colon and 38% were right sided. The interval from the original injury to colostomy takedown varied from 20 to 465 days, with a mean of 144 days. The mean postoperative hospital stay for the entire group was 15.13 days at a cost of


Journal of Trauma-injury Infection and Critical Care | 2000

Significance of minimal or no intraperitoneal fluid visible on CT scan associated with blunt liver and splenic injuries: A multicenter analysis

M. Gage Ochsner; Margaret M. Knudson; H. Leon Pachter; David B. Hoyt; Thomas H. Cogbill; Clyde E. McAuley; Frank E. Davis; Stan Rogers; Amber A. Guth; Joan Garcia; Pam Lambert; Norman Thomson; Scott Evans; Emil J. Balthazar; Giovanna Casola; Mark A. Nigogosyan; Richard Barr

13,995. There were no deaths and no anastomotic leaks in the entire series, but a morbidity rate of 25% ensued. Small bowel obstruction was the most frequent significant complication, occurring in ten patients (11.5%) and resulting in a prolongation of hospital stay by 7 days at an additional cost of

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