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Dive into the research topics where Peter F. Crookes is active.

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Featured researches published by Peter F. Crookes.


Journal of Clinical Oncology | 1998

ERCC1 mRNA levels complement thymidylate synthase mRNA levels in predicting response and survival for gastric cancer patients receiving combination cisplatin and fluorouracil chemotherapy.

Ralf Metzger; Cynthia G. Leichman; Kathleen D. Danenberg; Peter V. Danenberg; Heinz-Josef Lenz; Kazuhiko Hayashi; Susan Groshen; Dennis Salonga; Hartley Cohen; Loren Laine; Peter F. Crookes; Howard Silberman; Joaquina Baranda; Brahma Konda; Lawrence Leichman

PURPOSE We have previously shown that relative thymidylate synthase (TS) mRNA levels in primary gastric adenocarcinomas treated with fluorouracil (5-FU) and cisplatin are inversely associated with response and survival. This is a presumed function of TS as a target for 5-FU activity. We now test the hypotheses that the relative mRNA level of the excision repair cross-complementing (ERCC1) gene is inversely associated with response and survival as an independent function of cisplatin efficacy. PATIENTS AND METHODS Patients had intact, untreated, primary gastric adenocarcinoma cancer and were evaluated for eligibility on a preoperative cisplatin infusion-5-FU protocol. cDNA, derived from primary gastric tumors before chemotherapy, was used to determine ERCC1 mRNA levels, expressed as the ratio of polymerase chain reaction (PCR) product of the ERCC1 gene and the beta-actin gene. RESULTS The median ERCC1 mRNA level from 38 primary gastric cancers (33 assessable for response) was 5.8 x 10(-3) (range, 1.8 x 10(-3) to 19.5 x 10(-3)). Of 17 responding patients, 13 (76%) were less than or equal to 5.8 x 10(-3) and four were greater than 5.8 x 10(-3) (P = .003). The median survival for patients with ERCC1 mRNA levels less than or equal to 5.8 x 10(-3) has not been reached, whereas for those greater than 5.8 x 10(-3) it was 5.4 months (P = .034). The median TS mRNA level, 3.7 x 10(-3) (range, 0.9 to 18.9) also segregated responsive versus resistant tumors (P = .024). With both ERCC1 and TS mRNA levels below their medians, 11 of 13 patients (85%) responded; with both ERCC1 and TS mRNA levels above their medians, two of 10 patients (20%) responded (P = .003). CONCLUSION Considered separately, either ERCC1 or TS mRNA levels in a primary gastric adenocarcinoma has a statistically significant relationship to response. ERCC1 mRNA levels have a statistically significant association with survival; in this cohort TS mRNA levels did not reach statistically significant association with survival as in our previous publication. Whether these molecular parameters are independent of each other as predictors of outcome remains to be determined.


Journal of The American College of Surgeons | 2000

Laparoscopic repair of large type III hiatal hernia: objective followup reveals high recurrence rate

Majid Hashemi; Jeffrey H. Peters; Tom R. DeMeester; James E. Huprich; Marcus L. Quek; Jeffrey A. Hagen; Peter F. Crookes; Jörg Theisen; Steven R. DeMeester; Lelan F. Sillin; Cedric G. Bremner

BACKGROUND Recent studies based on symptomatic outcomes analyses have shown that laparoscopic repair of large type III hiatal hernias is safe, successful, and equivalent to open repair. These outcomes analyses were based on a relatively short followup period and lack objective confirmation that the hernia has not recurred. The aim of this study was to compare the outcomes of laparoscopic and open repair of large type III hiatal hernia using both symptomatic evaluation and barium study to assess the integrity of the repair. STUDY DESIGN Fifty-four patients underwent repair of a large type III hiatal hernia between 1985 and 1998. The surgical approach was laparotomy in 13, thoracotomy in 14, and laparoscopy in 27. An antireflux procedure was included in all patients. Symptomatic outcomes were assessed using a structured questionnaire at a median of 24 months and was complete in 51 of 54 patients (94%). A single radiologist, without knowledge of the operative procedure, assessed the integrity of the repair using video esophagram. Videos were performed at a median of 27 months (35 months open and 17 laparoscopic) and were completed in 41 of 54 patients (75%). RESULTS Symptomatic outcomes were similar in both groups with excellent or good outcomes in 76% of the patients after laparoscopic repair and 88% after an open repair. Reherniation was present in 12 patients and was asymptomatic in 7. A recurrent hernia was present in 12 of the 41 patients (29%) who returned for a followup video esophagram. Forty-two percent (9 of 21) of the laparoscopic group had a recurrent hernia compared with 15% (3 of 20) of the open group (p < 0.001 log-rank value on recurrence-free followup). CONCLUSIONS Laparoscopic repair of type III hiatal hernias is associated with a disturbingly high (42%) prevalence of recurrent hernia. More than half such recurrences have few, if any, symptoms.


Journal of Clinical Oncology | 1996

Thymidylate synthase mRNA level in adenocarcinoma of the stomach: a predictor for primary tumor response and overall survival.

Heinz-Josef Lenz; Cynthia G. Leichman; Kathleen D. Danenberg; Peter V. Danenberg; Susan Groshen; Hartley Cohen; Loren Laine; Peter F. Crookes; Howard Silberman; Joaquina Baranda; Yolee Garcia; James Li; Lawrence Leichman

PURPOSE We tested the hypothesis that polymerase chain reaction (PCR) quantitation of the enzyme thymidylate synthase (TS) within a primary adenocarcinoma of the stomach, has an inverse relationship to response and survival for patients who receive fluorouracil (5FU)-based chemotherapy. PATIENTS AND METHODS Before systemic chemotherapy, the genetic expression of TS (TSmRNA level) was determined using a PCR method. Gene expression was calculated by determining the ratio between the amount of radiolabeled PCR product with the linear amplification range of the TS gene and the beta-actin gene. Chemotherapy consisted of two cycles of protracted infusion (PI) 5FU 200 mg/m2/d administered for 3 weeks with leucovorin 20 mg/m2/w. Cisplatin 100 mg/m2 was administered on day 1. RESULTS Sixty-five patients with primary gastric cancer had a median TS mRNA level of 4.6 x 10(-3) (range, 0.9 to 20.1 x 10(-3)). Thirty-five percent of patients had measurable responses in their primary tumors. The mean gastric cancer TSmRNA level in responding and resistant patients is statistically significant (P < .001). The median survival time was 43+ months for treated patients with TSmRNA levels less than the median and 6 months for those with TS m-RNA levels greater than the median (P = .003). CONCLUSION The genetic expression of TS (TSmRNA level) influences response to 5FU-based chemotherapy and survival for a cohort of patients with primary gastric cancer. Confirmation of these data could lead to therapeutic decisions based on specific molecular properties within a tumor.


Annals of Surgery | 1997

Inflammation and specialized intestinal metaplasia of cardiac mucosa is a manifestation of gastroesophageal reflux disease.

Stefan Öberg; Jeffrey H. Peters; Tom R. DeMeester; Para Chandrasoma; Jeffrey A. Hagen; Adrian P. Ireland; Manfred P. Ritter; Rodney J. Mason; Peter F. Crookes; Cedric G. Bremner

OBJECTIVE The purpose of the study was to test the hypothesis that cardiac mucosa, carditis, and specialized intestinal metaplasia at an endoscopically normal-appearing cardia are manifestations of gastroesophageal reflux disease. SUMMARY BACKGROUND DATA In the absence of esophageal mucosal injury, the diagnosis of gastroesophageal reflux disease currently rests on 24-hour pH monitoring. Histologic examination of the esophagus is not useful. The recent identification of specialized intestinal metaplasia at the cardia, along with the observation that it occurs in inflamed cardiac mucosa, led the authors to focus on the type and condition of the mucosa at the gastroesophageal junction and its relation to gastroesophageal reflux disease. METHODS Three hundred thirty-four consecutive patients with symptoms of foregut disease, no evidence of columnar-lined esophagus, and no history of gastric or esophageal surgery were evaluated by 1) endoscopic biopsies above, at, and below the gastroesophageal junction; 2) esophageal motility; and 3) 24-hour esophageal pH monitoring. The patients were divided into groups depending on the histologic presence of cardiac epithelium with and without inflammation or associated intestinal metaplasia. Markers of gastroesophageal reflux disease were compared between groups (i.e., lower esophageal sphincter characteristics, esophageal acid exposure, the presence of endoscopic erosive esophagitis, and hiatal hernia). RESULTS When cardiac epithelium was found, it was inflamed in 96% of the patients. The presence of cardiac epithelium and carditis was associated with deterioration of lower esophageal sphincter characteristics and increased esophageal acid exposure. Esophagitis occurred more commonly in patients with carditis whose sphincter, on manometry, was structurally defective. Specialized intestinal metaplasia at the cardia was only seen in inflamed cardiac mucosa, and its prevalence increased both with increasing acid exposure and with the presence of esophagitis. CONCLUSION The findings of cardiac mucosa, carditis, and intestinal metaplasia in an endoscopically normal-appearing gastroesophageal junction are histologic indicators of gastroesophageal reflux disease. These findings may be among the earliest signs of gastroesophageal reflux and contribute to the authors understanding of the pathophysiology of the disease process.


Journal of Gastrointestinal Surgery | 1999

Multivariate analysis of factors predicting outcome after laparoscopic Nissen fundoplication.

Guilherme M. Campos; Jeffrey H. Peters; Tom R. DeMeester; Stefan Öberg; Peter F. Crookes; Silvia Tan; Steven R. DeMeester; Jeffrey A. Hagen; Cedric G. Bremner

Laparoscopic Nissen fundoplication has been applied with increasing frequency in the treatment of gastroesophageal reflux disease. The aim of this study was to determine the variahles that predict outcome of laparoscopic Nissen fundoplication. A multivariate analysis was performed on data from 199 consecutive patients undergoing laparoscopic Nissen fundoplication. Variables included age, sex, body mass index, primary symptoms, clinical response to acid suppression therapy, erosive esophagitis, 24-hour esophageal pH score, and the percentage of time the esophageal pH was less than 4 on 24-hour pH monitoring, lower esophageal sphincter competence, status of the esophageal body motility, hiatal hernia, carditis, intestinal metaplasia of cardiac epithelium limited to the gastroesophageal junction, and Barrett’s esophagus of any length. Clinical outcome was obtained from all patients at a median follow-up of 15 months (range 6 to 74 months) after surgery. One hundred seventy-three patients had an excellent or good outcome (87%) and 26 had a fair or poor outcome. Three factors were significantly predictive of a successful outcome: an abnormal 24-hour pH score (odds ratio = 5.4; 95% confidence interval [CI] = 1.9–15.3), a typical primary symptom (odds ratio = 5.1; 95% CI = 1.9–13.6), and a clinical response to acid suppression therapy (odds ratio = 3.3; 95% CI = 1.3 -8.7). We conclude that 24-hour pH monitoring provides the strongest outcome predictor of laparoscopic Nissen fundoplication and that outcome is based more on the correct identification of the disease than on its severity.


Obesity Surgery | 2004

Longitudinal Gastrectomy as a Treatment for the High-Risk Super-Obese Patient

Gidon Almogy; Peter F. Crookes; Gary J. Anthone

Background: Bariatric surgery in patients with significant co-morbid conditions is associated with increased perioperative risk. Methods: From 1995-2001, 795 patients were operated upon at our institution for the diagnosis of morbid obesity. Of these, 671 (84.4%) had the duodenal switch (DS) procedure. Longitudinal gastrectomy (LG) entails a greater curvature linear gastrectomy creating a gastric tube with a volume of 100 ml along the lesser curvature of the stomach. This procedure was performed for 21 patients (median age 50.5, median BMI 56). 9 patients were offered LG preoperatively because of their known high perioperative risks. 12 patients were initially planned for DS, but the procedure was limited to LG alone because of either unexpected intraoperative findings (n=9) or intraoperative hemodynamic instability (n=3). 5 patients developed complications, and there were no deaths. Results: 19 out of 21 patients were available for a median follow-up of 17.5 months (6.25-20.25). Median weight loss and median %EWL at 12 months were 44.5 kg and 45.1%, respectively. Estimated daily dietary volume at 1 year was 35% of preoperative values. Of 10 patients followed for ≥ 1 year, 4 of 10 achieved more than 50% EWL and 8 patients were taking less or were completely off medications for diabetes, hypertension and congestive heart failure. Weight loss plateaued at 1 year for the majority of patients. Conclusions: LG is a safe and effective option for high-risk morbidly obese patients. Weight reduction is accomplished by limitation of caloric intake. LG can be offered to high-risk morbidly obese patients as an interim procedure to help decrease perioperative risk before DS.


Obesity Surgery | 2006

Sleeve Gastrectomy in the High-Risk Patient

Nahid Hamoui; Gary J. Anthone; Howard S. Kaufman; Peter F. Crookes

Background: One of the surgical options available for the super-obese patient is the sleeve gastrectomy. We present results of this operation in a series of 118 patients. Methods: The charts of all patients who have had the sleeve gastrectomy performed were reviewed for demographic data, complications, weight, and nutritional parameters. Results: Median age was 47 years (16-70). Median BMI was 55 kg/m2 (37-108), with 73% of patients having a BMI ≥50 kg/m2. 41% of the patients were male. The operation was performed by laparotomy in all but three cases, which were performed laparoscopically. Median hospital stay was 6 days (3-59). There was one perioperative death (0.85%). 18 patients (15.3%) had postoperative complications. Median percent excess weight loss was 37.8% at 6 months, 49.4% at 12 months, and 47.3% at 24 months. Median follow-up was 13 months (1-66). At 1 year postoperatively, the percentage of patients with normal serum levels of albumin was 100%, hemoglobin 86.1%, and calcium 87.2%, compared to 98.1%, 85.6%, and 94.3% preoperatively. 6 patients requested conversion to a duodenal switch during the follow-up period; all left the hospital in 4-6 days without major complication. Conclusions: Although the sleeve gastrectomy does not result in as much weight loss as the duodenal switch or gastric bypass, it can be used as a stand-alone operation or as a bridge to more complex procedures in the high-risk super-obese patient.


Journal of Gastrointestinal Surgery | 2000

Suppression of gastric acid secretion in patients with gastroesophageal reflux disease results in gastric bacterial overgrowth and deconjugation of bile acids

Jörg Theisen; Dhiren Nehra; Diane M. Citron; Jan Johansson; Jeffrey A. Hagen; Peter F. Crookes; Steven R. DeMeester; Cedric G. Bremner; Tom R. DeMeester; Jeffrey H. Peters

The aim of this study was to test the hypothesis that gastric bacterial overgrowth is a side effect of acid suppression therapy in patients with gastroesophageal reflux disease (GERD) and that the bacteria-contaminated gastric milieu is responsible for an increased amount of deconjugated bile acids. Thirty patients with GERD who were treated with 40 mg of omeprazole for at least 3 months and 10 patients with GERD who were off medication for at least 2 weeks were studied. At the time of upper endoscopy, 10 ml of gastric fluid was aspirated and analyzed for bacterial growth and bile acids. Bacterial over-growth was defined by the presence of more than 1000 bacteria/ml. Bile acids were quantified via high-performance liquid chromatography. Eleven of the 30 patients taking omeprazole had bacterial over-growth compared to one of the 10 control patients. The median pH in the bacteria-positive patients was 5.3 compared to 2.6 in those who were free of bacteria and 3.5 in the control patients who were off medication. Bacterial overgrowth only occurred when the pH was >3.8. The ratio of conjugated to unconjugated bile acids changed from 4:1 in the patients without bacterial overgrowth to 1:3 in those with bacterial growth greater than 1000/ml. Proton pump inhibitor therapy in patients with GERD results in a high prevalence of gastric bacterial overgrowth. The presence of bacterial overgrowth markedly increases the concentration of unconjugated bile acids. These findings may have implications in the pathophysiology of gastroesophageal mucosal injury.


The Journal of Thoracic and Cardiovascular Surgery | 1999

Prevalence and location of nodal metastases in distal esophageal adenocarcinoma confined to the wall: Implications for therapy

John J. Nigro; Jeffrey A. Hagen; Tom R. DeMeester; Steven R. DeMeester; Jeffrey H. Peters; Stefan Öberg; Jörg Theisen; Milton Kiyabu; Peter F. Crookes; Cedric G. Bremner

OBJECTIVE The purpose of this study was to characterize the prevalence and location of regional lymph node metastases in adenocarcinoma confined to the esophagal wall, to determine the extent of dissection required, and to investigate the applicability of nonoperative therapy. METHODS Histologic evaluation of the resected specimens after en bloc esophagogastrectomy with mediastinal and abdominal lymphadenectomy was performed on 37 patients with adenocarcinoma confined to the esophageal wall. Follow-up was complete in all patients (median 24 months). RESULTS Fifteen patients (41%) had intramucosal tumors. Twelve (32%) had submucosal tumors and 10 (27%) had muscular invasion. The prevalence of regional lymph node metastases (15/37 patients, 41%) increased progressively with depth of tumor invasion, with involved nodes identified in 80% of patients with muscular invasion. Lymph node metastases were also more common at distant node stations in intramuscular tumors (5/10, 50%). Actuarial survival for the entire group was 63% at 5 years. Recurrence was identified in 6 of the 37 patients (16%), with the risk of recurrence correlating with tumor depth. CONCLUSIONS Tumor depth is a strong predictor of the probabilities of regional lymph node metastases, the likelihood of involvement of distant node groups, and the risk of recurrence. Patients with invasion of the muscular wall are at particularly high risk. En bloc esophagectomy with mediastinal and abdominal lymphadenectomy has the highest likelihood of achieving an R0 resection. The long-term survival and low recurrence rate achieved with an en bloc esophagectomy emphasizes the importance of an aggressive lymph node dissection to remove all potentially involved nodes.


Annals of Surgery | 2001

Long-Term Outcome of Antireflux Surgery in Patients With Barrett’s Esophagus

Wayne L. Hofstetter; Jeffrey H. Peters; Tom R. DeMeester; Jeffrey A. Hagen; Steven R. DeMeester; Peter F. Crookes; Peter I. Tsai; Farzana Banki; Cedric G. Bremner

ObjectiveTo assess the long-term outcome of antireflux surgery in patients with Barrett’s esophagus. Summary Background DataThe prevalence of Barrett’s esophagus is increasing, and its treatment is problematic. Antireflux surgery has the potential to stop reflux and induce a quiescent mucosa. Its long-term outcome, however, has recently been challenged with reports of poor control of reflux and the inability to prevent progression to cancer. MethodsThe outcome of antireflux surgery was studied in 97 patients with Barrett’s esophagus. Follow-up was complete in 88% (85/97) at a median of 5 years. Fifty-nine had long-segment and 26 short-segment Barrett’s. Patients with intestinal metaplasia of the cardia were excluded. Fifty patients underwent a laparoscopic procedure, 20 a transthoracic procedure, and 3 abdominal Nissen operations. Nine had a Collis-Belsey procedure and three had other partial wraps. Outcome measures included relief of reflux symptoms (all), patients’ perception of the result (all), upper endoscopy and histology (n = 79), and postoperative 24-hour pH monitoring (n = 21). ResultsAt a median follow-up of 5 years, reflux symptoms were absent in 67 of 85 patients (79%). Eighteen (20%) developed recurrent symptoms; four had returned to taking daily acid-suppression medication. Seven patients underwent a secondary repair and were asymptomatic, increasing the eventual successful outcome to 87%. Recurrent symptoms were most common in patients undergoing Collis-Belsey (33%) and laparoscopic Nissen (26%) procedures and least common after a transthoracic Nissen operation (5%). The results of postoperative 24-hour pH monitoring were normal in 17 of 21 (81%). Recurrent hiatal hernias were detected in 17 of 79 patients studied; 6 were asymptomatic. Seventy-seven percent of the patients considered themselves cured, 22% considered their condition to be improved, and 97% were satisfied. Low-grade dysplasia regressed to nondysplastic Barrett’s in 7 of 16 (44%), and intestinal metaplasia regressed to cardiac mucosa in 9 of 63 (14%). Low-grade dysplasia developed in 4 of 63 (6%) patients. No patient developed high-grade dysplasia or cancer in 410 patient-years of follow-up. ConclusionsAfter antireflux surgery, most patients with Barrett’s enjoy long-lasting relief of reflux symptoms, and nearly all patients consider themselves cured or improved. Mild symptoms recur in one fifth. Importantly, dysplasia regressed in nearly half of the patients in whom it was present before surgery, intestinal metaplasia disappeared in 14% of patients, and high-grade dysplasia and adenocarcinoma were prevented in all.

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Tom R. DeMeester

University of Southern California

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Cedric G. Bremner

University of Southern California

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Jeffrey A. Hagen

University of Southern California

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Steven R. DeMeester

University of Southern California

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Nahid Hamoui

University of Southern California

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Gary J. Anthone

University of Southern California

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Rodney J. Mason

University of Southern California

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T. R. DeMeester

University of Southern California

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