Biomedical subjects

Christopher J Gannon

Publications and source records attributed to Christopher J Gannon.

8 recordsLinked to original sources

PubMed2006

Accuracy of lymphatic mapping and sentinel lymph node biopsy after previous wide local excision in patients with primary melanoma.

BACKGROUND: Sentinel lymph node (SLN) status is the most important prognostic factor with respect to the survival of patients with primary cutaneous melanoma. However, lymphatic mapping and SLN biopsies (LM/SLNBs) performed in patients who have had a wide local excision (WLE) may not accurately reflect the pathologic status of the draining lymph node basins. The purpose of this study was to assess the feasibility and accuracy of LM/SLNB in patients who have had a previous WLE. METHODS: A single-institution database was examined to identify patients who had a WLE before LM/SLNB and patients who had a concomitant LM/SLNB. Primary clinicopathologic features (age, tumor thickness, and ulceration), SLN identification rate, SLN pathologic status, and the incidence and sites of recurrences were compared between patients with and without prior WLE. RESULTS: Of the 1395 patients identified, 104 had WLE before LM/SLNB. The mean preoperative WLE radial margin was 1.4 cm (median, 1.0 cm). LM/SLNB was successful in 103 of 104 (99%) patients. Age, tumor thickness, incidence of ulceration, and incidence of SLN positivity in the group with prior WLE were similar to those of the cohort of patients who had concomitant LM/SLNB and WLE (n = 1291). In 97 (93%) of the 104 prior-WLE patients, the surgical defects were closed by either primary closure or skin graft; 7 patients (7%) had rotational flaps. The median follow-up of these 104 patients was 51 months. Among the prior-WLE group, 19 patients (18%) had a positive SLNB; of these 19 patients, 4 (21%) had recurrences (3 distant failures and 1 local and distant failure). There were no lymph node recurrences-in a mapped or unmapped basin-in these 104 patients with a negative or positive SLNB. CONCLUSIONS: SLNs can be successfully identified and accurately reflect the status of the regional lymph node basin in carefully selected melanoma patients with a previous WLE. Prior WLE does not appear to adversely impact the ability to detect lymphatic metastases, although the utility of LM/SLNB in patients who have undergone extensive reconstruction of the primary excision site remains to be defined. Because more extensive surgery may be required to accomplish accurate lymph node staging in patients who have undergone prior WLE-including the possible removal of SLNs from additional lymph node basins and an additional surgical procedure-to minimize morbidity and cost, concomitant WLE and LM/SLNB is strongly preferred whenever possible.

Adolescent↗

PubMed2006

Mammalian pharmacokinetics of carbon nanotubes using intrinsic near-infrared fluorescence.

Individualized, chemically pristine single-walled carbon nanotubes have been intravenously administered to rabbits and monitored through their characteristic near-infrared fluorescence. Spectra indicated that blood proteins displaced the nanotube coating of synthetic surfactant molecules within seconds. The nanotube concentration in the blood serum decreased exponentially with a half-life of 1.0 +/- 0.1 h. No adverse effects from low-level nanotube exposure could be detected from behavior or pathological examination. At 24 h after i.v. administration, significant concentrations of nanotubes were found only in the liver. These results demonstrate that debundled single-walled carbon nanotubes are high-contrast near-infrared fluorophores that can be sensitively and selectively tracked in mammalian tissues using optical methods. In addition, the absence of acute toxicity and promising circulation persistence suggest the potential of carbon nanotubes in future pharmaceutical applications.

Animals↗

PubMed2005

Small-bowel diverticulosis.

Diffuse jejunoileal diverticulosis with pneumoperitoneum but without peritonitis is an uncommon but well-documented entity. Cases of jejunoileal diverticular perforation in which the perforation is evident are managed with resection of the diseased bowel and primary anastomosis. In the absence of an intraoperative finding of a perforation or an area of discrete inflammation, copious irrigation and closure of the abdomen is appropriate in cases of diffuse small-bowel diverticulosis.

Abdominal Pain↗

PubMed2005

The role of focal liver ablation in the treatment of unresectable primary and secondary malignant liver tumors.

Surgical resection is often the first-line treatment option for primary and select metastatic hepatic malignancies. A minority of patients with hepatocellular carcinoma undergo potentially curative resection. Similarly, patients with liver-only metastasis are candidates for resection less than 15% of the time because of bilobar disease in which resection would sacrifice too great a volume of hepatic parenchyma, tumor proximity to major vascular or biliary structures thus preventing adequate margins, or unfavorable tumor biology. Ablative techniques directed at tumor elimination while minimizing injury to the surrounding functional hepatic parenchyma may be offered to select patients with unresectable cancers. Radiofrequency ablation, percutaneous ethanol injection, transarterial chemoembolization, cryoablation, microwave coagulation, and laser-induced interstitial thermotherapy all offer potential local tumor control and occasionally achieve long-term disease-free survival. This review focuses on the indications, anticipated benefits, and limitations of these ablative techniques.

Antineoplastic Agents↗

PubMed2004

Male gender is associated with increased risk for postinjury pneumonia.

Nosocomial pneumonia in trauma patients is a significant source of resource utilization and mortality. We have previously described increased rates of pneumonia in male trauma patients in a single institution study. In that study, female trauma patients had a lower incidence of postinjury pneumonia but a higher relative risk for mortality when they did develop pneumonia. We sought to investigate the hypothesis that male trauma patients have an increased incidence of postinjury pneumonia in a separate population-based dataset. Prospective data were collected on 30,288 trauma patients (26,231 blunt injuries, 4057 penetrating injuries) admitted to all trauma centers (n = 26) in Pennsylvania over 24 months (January 1996 to December 1997). Gender differences in pneumonia were determined for the entire dataset. A second analysis examined all blunt injury patients and excluded all patients with a hospital length of stay less than 24 h, eliminating patients who expired early after admission. In trauma patients with minor injury (ISS < 15), there was no significant difference between male and female patients in the rate of postinjury pneumonia (male 1.37%, female 1.11%). In the moderate-injury group (ISS > 15), male trauma patients had a significantly increased incidence of postinjury pneumonia (ISS 15-30, male 8.85%, female 6.45%; ISS > 30, male 24.35%, female 17.30%). Logistic regression analysis of blunt trauma patients revealed that gender, ISS, injury type, admission Revised Trauma Score (RTS), admission respiratory rate, history of cardiac disease, and history of cancer were all independent predictors of pneumonia. Trauma patients with nosocomial pneumonia had a significantly higher mortality rate (P < 0.001) than patients without pneumonia. There was no gender-specific difference in mortality among pneumonia patients. Male gender is significantly associated with an increased incidence of postinjury pneumonia. In contrast to our initial study, there was no gender difference in postinjury pneumonia mortality rates identified in this population-based study.

Adolescent↗

PubMed2002

A statewide population-based study of gender differences in trauma: validation of a prior single-institution study.

BACKGROUND: Women usually have lower mortality rates than men do at any age. This pattern is observed for most causes of death from chronic diseases. Significant controversy still exists about gender differences in outcomes in trauma. We previously reported no differences in in-hospital mortality based on gender in a large single-institution study (n= 18,892) that had a significant limitation in that it was not population based. This current study was performed to validate our earlier findings in a separate, statewide, population-based dataset of trauma victims. STUDY DESIGN: Prospective data were collected on 22,332 trauma patients (18,432 blunt, 3,900 penetrating) admitted to all trauma centers (n = 26) in Pennsylvania over 24 months (January 1996 to December 1997). Gender differences in in-hospital mortality were determined for the entire dataset and for the subsets of blunt and penetrating injury patients. A second analysis examined all blunt injury patients and excluded all patients with a hospital length of stay of less than 24 hours, eliminating patients who expired soon after admission. The null hypothesis was that female gender is protective in trauma outcomes. RESULTS: Multiple logistic regression analysis identified age (odds ratio [OR] 1.03, confidence interval [CI] 1.02 to 1.03), Injury Severity Score (OR 1.06, CI 1.05 to 1.06), non-Caucasian race (OR 1.72, CI 1.39 to 2.15), blunt injury type (OR 0.327, CI 0.26 to 0.41), and Revised Trauma Score (OR 0.44, CI 0.41 to 0.47) as independent predictors of in-hospital mortality in trauma. Preexisting diseases, including cardiac disease (OR 1.53, CI 1.12 to 2.09) and malignancy (OR 4.08, CI 1.64 to 10.17), were also identified as independent predictors of in-hospital mortality in trauma. Female gender was not associated with decreased mortality (OR 0.83, CI 0.67 to 1.03, p = 0.093). A second multiple regression analysis in blunt trauma patients admitted for longer than 24 hours (which eliminated early deaths and patients with minor injuries) determined that in-hospital mortality was not significantly different in male or female blunt trauma patients stratified by Injury Severity Score and age. The same factors that were predictive of in-hospital mortality in the total dataset were also significant in this secondary analysis. CONCLUSIONS: These population-based data confirm that female gender does not adversely affect in-hospital mortality in trauma when patients are appropriately stratified for other variables, including Injury Severity Score and age, that do significantly affect outcomes.

Adult↗

PubMed2002

Severe anemia after gastrointestinal hemorrhage in a Jehovah's Witness: new treatment strategies.

OBJECTIVE: Management of severe anemia in a critically ill Jehovah's Witness is challenging. In the past, conservative therapy was the only option available to the practitioner. Recently, new interventional treatment strategies have become available, including human and bovine hemoglobin substitutes and high-dose recombinant human erythropoietin. DESIGN: Case report. SETTING: Intensive care unit in a quaternary care center. PATIENT: A patient with severe, life-threatening anemia caused by gastrointestinal hemorrhage who refused all blood products on religious grounds. INTERVENTION: Bovine hemoglobin substitute and high-dose recombinant human erythropoietin. CASE STUDY: A 50-yr-old Jehovah's Witness presented with massive upper gastrointestinal hemorrhage; initial hemoglobin was 3.5 g/dL. Endoscopy revealed a prepyloric ulcer, and hemorrhage control was achieved by epinephrine injections into the peri-ulcer mucosa. Despite control of hemorrhage, the patient became hemodynamically unstable. A total of 7 units of a bovine hemoglobin-based oxygen carrying compound (HBOC-201) was administered to enhance the patient's oxygen delivery. High-dose recombinant human erythropoietin was administered daily (500 units/kg). Hemoglobin levels were initially maintained and then slowly increased to a maximum of 7.6 g/dL on day 24 of therapy. CONCLUSION: This case demonstrates that the concurrent administration of hemoglobin-based oxygen carriers and recombinant human erythropoietin in severe, life-threatening anemia (hemoglobin, 3.5 g/dL) was associated with patient survival and a significant increase in hemoglobin to 7.6 g/dL, without the administration of allogeneic blood. Hemoglobin-based oxygen carriers can adequately serve as initial therapy to maintain tissue oxygen delivery while awaiting the maximal effect of recombinant erythropoietin on bone marrow red blood cell production. High-dose recombinant human erythropoietin offers these patients the best chance for normalization of hematocrit and survival in the long term.

Anemia↗

PubMed2002

Preoperative anemia in colon cancer: assessment of risk factors.

Anemia is common in cancer patients and is associated with reduced survival. Recent studies document that treatment of anemia with blood transfusion in cancer patients is associated with increased infection risk, tumor recurrence, and mortality. We therefore investigated the incidence of preoperative anemia in colorectal cancer and assessed risk factors for anemia. Prospective data were collected on 311 patients diagnosed with colorectal cancer over a 6-year period from 1994 through 1999. Patients were stratified by age, gender, presenting complaint, preoperative hematocrit, American Joint Committee on Cancer (AJCC) stage, and TNM classification. Discrete variables were compared using Pearson's Chi-square analysis. Continuous variables were compared using Student's t test. Differences were considered significant when P < 0.05. The mean age of the study cohort was 67 +/- 9.2 with 98 per cent of the study population being male. The mean AJCC stage was 2.2 +/- 1.2 and the mean preoperative hematocrit was 35 +/- 7.9 with an incidence of 46.1 per cent. The most common presenting complaints were hematochezia (n = 59), anemia (n = 51), heme-occult-positive stool (n = 33), bowel obstruction (n = 26), abdominal pain (n = 21), and palpable mass (n = 13). Preoperative anemia was most common in patients with right colon cancer with an incidence of 57.6 per cent followed by left colon cancer (42.2%) and rectal cancer (29.8%). Patients with right colon cancer had significantly lower preoperative hematocrits compared with left colon cancer (33 +/- 8.5 vs 36 +/- 7.4; P < 0.01) and rectal cancer (33 +/- 8.5 vs 38 +/- 6.0; P < 0.0001). Patients with right colon cancer also had significantly increased stage at presentation compared with left colon cancer (2.3 +/- 1.3 vs 2.1 +/- 1.2; P < 0.02). Age was not a significant risk factor for preoperative anemia in colorectal cancer. We conclude that there is a high incidence of anemia in patients with colon cancer. Patients with right colon cancer had significantly lower preoperative hematocrits and higher stage of cancer at diagnosis. Complete colon evaluation with colonoscopy is warranted in patients with anemia to improve earlier diagnosis of right colon cancer. A clinical trial of preoperative treatment of anemic colorectal cancer patients with recombinant human erythropoietin is warranted.

Aged↗