Durable Complete Responses in Metastatic Colorectal Cancer Treated with Chemotherapy Alone

Background/Purpose: The median survival for patients with metastatic colorectal cancer (mCRC) has progressively increased over the past decades. Since the introduction of 5-fluorouracil (5-FU)-based chemotherapy, followed by hepatic resection of metastases, and more recently the adoption of newer chemotherapeutic regimens associated with targeted therapy, the gains are getting more substantial. Despite the recognition of the potential for long-term survival after surgical resection of metastatic disease, long-term survival data to determine the potential curative role of chemotherapy alone is lacking. Methods: We performed a retrospective review of 2751 patients who presented with mCRC at The MD Anderson Cancer Center from 1990 through 2003. Patients alive at 5 years who achieved complete response with chemotherapy and were not submitted to any surgical or interventional procedures directed to the metastatic sites were included in the analysis. Results: The 5-year overall survival rate for all patients with mCRC during this period was 10.8%. Among these long-term survivors, 2.2% achieved a sustained complete response after chemotherapy (all 6 with fluoropyrimidines and 2 with irinotecan) as the only treatment modality and were without evidence of disease until the last follow-up visit (median of 10.3 years). This number corresponds to 0.24% (6 of 2541) of all patients with mCRC included in this review. Conclusion: Cure with chemotherapy alone is possible for a very small number of patients with metastatic colorectal cancer. Improved therapies are increasing complete response rates, but the impact of modern chemotherapy on durable complete responses will require additional follow up.

Short-term specialized enteral diet fails to attenuate malnutrition impairment of experimental open wound acute healing

Objective: We assessed the effect of enteral refeeding on the morphology, gene expression, and contraction of acute open wounds in previously malnourished rats using two different enteral diets. Methods: Adult male isogenic Lewis rats divided into two groups (eutrophic, n = 30; and previously malnourished, 12-15% body weight loss, n = 27) were subjected to cutaneous dorsal wounds and gastrostomy. Control rats received a standard oral diet (AIN-93M chow) plus enteral saline solution. Subject rats received chow plus a standard enteral diet or an enteral diet enriched with arginine and antioxidants. On post-trauma days 7 and 14, wound granulation tissue samples were collected for morphologic analysis using hematoxylin and eosin and picrosirius stain or immunohistochemistry slides and real-time polymerase chain reaction for collagen I and III gene expression. Wound contraction was also evaluated by comparing wound images from days 0,7, and 14. Results: Malnourished control rats had increased intensity and duration of wound inflammation, impaired increase of fibroblast cells contingent on post-trauma days 7 to 14, decreased expression of collagen III, and less wound contraction compared with eutrophic control rats. A specialized enteral diet did not improve wound healing of malnourished rats but did promote wound contraction at post-trauma day 7 in eutrophic rats. Conclusion: Short-term enteral refeeding, even with a specialized diet, failed to protect previously wounded malnourished rats from a prolonged inflammatory phase and impaired healing. (C) 2010 Elsevier Inc. All rights reserved.

Increasing the Rates of Complete Response to Neoadjuvant Chemoradiotherapy for Distal Rectal Cancer: Results of a Prospective Study Using Additional Chemotherapy During the Resting Period

OBJECTIVES: Addition of chemotherapy in the resting period between radiotherapy completion and response assessment during neoadjuvant treatment for distal rectal cancer could potentially increase rates of complete tumor regression. The purpose of this study was to evaluate toxicity rates and the impact of an extended neoadjuvant chemoradiation regimen on complete response rates. METHODS: Thirty-four consecutive patients with nonmetastatic distal rectal cancer were prospectively included. Patients were managed by 5,400 Gy of radiation and 5-fluorouracil/leucovorin-based chemotherapy given for three consecutive days every 21 days for six cycles (three cycles concomitant with radiotherapy). Tumor response assessment was performed at ten weeks from radiation completion. Patients with complete clinical response were strictly monitored and were not immediately operated on. Patients with incomplete clinical response were referred to surgery. RESULTS: Twenty-nine patients had completed 12 months of follow-up and were included in this preliminary analysis. Twenty-eight (97%) successfully completed treatment. Fifteen of 16 patients had Grade III toxicities that were skin-related (93%). Median follow-up was 23 months. Fourteen patients (48%) were considered as complete clinical responders sustained for at least 12 months (median, 24 months) after chemoradiation completion by clinical assessment alone. An additional five patients (17%) were considered as complete responders with ypT0 results after full-thickness local excision. Overall, the complete response rate was 65%. CONCLUSIONS: The addition of chemotherapy during the resting period after neoadjuvant chemoradiation is associated with acceptable toxicity and high tolerability rates. The considerably high rates of complete response in this preliminary series requires further follow-up, but they may provide valuable information for future prospective, randomized trials.

Gene expression profile of residual breast cancer after doxorubicin and cyclophosphamide neoadjuvant chemotherapy

In breast cancer patients, primary chemotherapy is associated with the same survival benefits as adjuvant chemotherapy. Residual tumors represent a clinical challenge, Lis they may be resistant to additional cycles of the same drugs. Our aim was to identify differential transcripts expressed in residual tumors, after neoadjuvant chemotherapy, that might be related with tumor resistance. Hence, 16 patients with paired tumor samples, collected before and after treatment (4 cycles doxorubicin/cyclophosphamide, AC) had their gene expression evaluated on cDNA microarray slides containing 4,608 genes. Three hundred and eighty-nine genes were differentially expressed (paired Student`s t-test, pFDR<0.01) between pre- and post-chemotherapy samples and among the regulated functions were the JNK cascade and cell death. Unsupervised hierarchical clustering identified one branch comprising exclusively, eight pre-chemotherapy samples and another branch, including the former correspondent eight post-chemotherapy samples and other 16 paired pre/post-chemotherapy samples. No differences in clinical and tumor parameters could explain this clustering. Another group of I I patients with paired samples had expression of selected genes determined by real-time RT-PCR and CTGF and DUSP1 were confirmed more expressed in post- as compared to pre-chemotherapy samples. After neoadjuvant chemotherapy some residual samples may retain their molecular signature while others present significant changes in their gene expression, probably induced by the treatment. CTGF and DUSP1 overexpression in residual samples may be a reflection of resistance to further administration of AC regimen.

Transcriptome changes induced by docetaxel in human mammary cell lines expressing different levels of ERBB2

The taxane docetaxel is currently the most effective chemotherapeutic drug for the treatment of advanced breast cancer. However, a considerable proportion of breast cancer patients do not respond positively to docetaxel. The mechanisms of docetaxel resistance are poorly understood. Overexpression of ERBB2 occurs in 15-30% of breast tumors and is associated with chemoresistance to a variety of anticancer drugs. In the present study, we sought to identify genes involved in ERBB2-mediated chemoresistance to docetaxel. We generated SAGE libraries from two human mammary cell lines expressing basal (HB4a) and high (C5.2) levels of ERBB2 before and after intensive exposure to docetaxel and identified potential ERBB2 target genes implicated in a variety of cellular processes including cell proliferation, cell adhesion, apoptosis and cytoskeleton organization. Comparison of the transcriptome of the cell lines before and after docetaxel exposure revealed substantially different expression patterns. Twenty-one differentially expressed genes between HB4a and C5.2 cell lines, before and after docetaxel treatment, were further analyzed by qPCR. The alterations in the expression patterns in HB4a and C5.2 cell lines in response to docetaxel treatment observed by SAGE analysis were confirmed by qPCR for the majority of the genes analyzed. Our study provides a comprehensive view of the expression changes induced in two human mammary cells expressing different levels of ERBB2 in response to docetaxel that could contribute to the elucidation of the mechanisms involved in ERBB2-mediated chemoresistance in breast cancer.

Effects of phonophoresis with Arnica montana onto acute inflammatory process in rat skeletal muscles: An experimental study

This study aimed at verifying the effects of phonophoresis associated with Arnica montana on the acute phase of an inflammatory muscle lesion. Forty Wistar male rats (300 +/- 50 g), of which the Tibialis Anterior muscle was surgically lesioned, were divided into four groups (n = 10 each): control group received no treatment; the ultrasound group (US) was treated in pulsed mode with 1-MHz frequency, 0.5 W/cm(2) intensity (spatial and temporal average - SATA), duty cycle of 1: 2 (2 ms on, 4 ms off, 50%), time of application 3 min per session, one session per day, for 3 days; the phonophoresis or ultrasound plus arnica (US+A) group was treated with arnica with the same US parameters plus arnica gel; and the arnica group (A) was submitted to massage with arnica gel, also for 3 min, once a day, for 3 days. Treatment started 24 h after the surgical lesion. On the 4th day after lesion creation, animals were sacrificed and sections of the lesioned, inflamed muscle were removed for quantitative (mononuclear and polymorphonuclear cell count) and qualitative histological analysis. Collected data from the 4 groups were statistically analyzed and the significance level set at p < 0.05. Results show higher mononuclear cell density in all three treated groups with no significant difference between them, but values were significantly different (p < 0.0001) when compared to control group`s. As to polymorphonuclear cell density, significant differences were found between control group (p = 0.0134) and US, US+A and A groups; the arnica group presented lesser density of polymorphonuclear cells when compared (p = 0.0134) to the other groups. No significant difference was found between US and US+A groups. While the massage with arnica gel proved to be an effective anti-inflammatory on acute muscle lesion in topic use, these results point to ineffectiveness of Arnica montana phonophoresis, US having seemingly checked or minimized its anti-inflammatory effect. (C) 2008 Elsevier B. V. All rights reserved.

Experimental models of sepsis and their clinical relevance

Sepsis remains a major cause of morbidity and mortality mainly because of sepsis-induced multiple organ dysfunction. In contrast to preclinical studies, most clinical trials of promising new treatment strategies for sepsis have failed to demonstrate efficacy. Although many reasons could account for this discrepancy, the misinterpretation of preclinical data obtained from experimental studies and especially the use of animal models that do not adequately mimic human sepsis may have been contributing factors. In this review, the potentials and limitations of various animal models of sepsis are discussed to clarify to which extent these findings are relevant to human sepsis. Such models include intravascular infusion of endotoxin or live bacteria, bacterial peritonitis, cecal ligation and perforation, soft tissue infection, pneumonia or meningitis models using different animal species including rats, mice, rabbits, dogs, pigs, sheep, and nonhuman primates. Despite several limitations, animal models remain essential in the development of all new therapies for sepsis and septic shock because they provide fundamental information about the pharmacokinetics, toxicity, and mechanism of drug action that cannot be replaced by other methods. New therapeutic agents should be studied in infection models, even after the initiation of the septic process. Furthermore, debility conditions need to be reproduced to avoid the exclusive use of healthy animals, which often do not represent the human septic patient.

Timing-dependent protection of hypertonic saline solution administration in experimental liver ischemia/reperfusion injury

Background. Diving liver ischemia, the decrease in mitochondrial energy causes cellular damage that is aggravated after reperfusion. This injury can trigger a systemic inflammatory syndrome, also producing remote organ damage. Several substances have been employed to decrease this inflammatory response during liver transplantation, liver resections, and hypovolemic shock. The aim of this study was to evaluate the effects of hypertonic saline solution and the best timing of administration to prevent organ injury during experimental liver ischemia/reperfusion. Methods. Rats underwent 1 hr of warm liver ischemia followed by reperfusion. Eighty-four rats Were allocated into 6 groups: sham group, control of ischemia group) (C), pre-ischemia treated NaCl 0.9% (ISS) and NaCl 7.5% (HTS) groups, pre-repefusion ISS, and HTS groups. Blood and tissue samples were collected 4 hr after reperfusion. Results. HTS showed beneficial effects in prevention of live ischemia/reperfusion injury. HTS groups developed increases in AST and ALT levels that were significantly less than ISS groups; however, the HTS pre-reperfusion group showed levels significantly less than the HTS pre-ischemia group. No differences in IL-6 and IL-10 levels, were observed. A significant decrease in mitochondrial dysfunction as well as hepatic edema was observed in the HTS pre-reperfusion group. Pulmonary vascular permeability Was significantly less in the pre-reperfusion HTS group compared to the ISS group. No differences in myeloperoxidase activity were observed. The liver histologic score was significantly less in the pre-reperfusion HTS group compared to the pre-ischemia I-ITS group. Conclusion. HTS ameliorated local and systemic injuries in experimental liver ischemia/reperfusion. Infusion of HTS in the pre-reperfusion period may be an important adjunct to accomplish the best results. (Surgery 2010;147:415-23.)

IS SPLENECTOMY A DYSLIPIDEMIC INTERVENTION? EXPERIMENTAL RESPONSE OF SERUM LIPIDS TO DIFFERENT DIETS AND OPERATIONS

Spleen removal may be recommended during organ transplantation in ABO-incompatible recipients as well as for hypoperfusion of the grafted liver, besides conventional surgical indications, but elevation of serum lipids has been observed in certain contexts. Aiming to analyze the influence of two dietary regimens on lipid profile, an experimental study was conducted. Methods: Male Wistar rats (n = 86, 333.0 +/- 32.2 g) were divided in four groups: group 1: controls; group 2: sham operation; group 3: total splenectomy; group 4: subtotal splenectomy with upper pole preservation; subgroups A (cholesterol reducing chow) and B (cholesterol-rich mixture) were established, and diet was given during 90 days. Total cholesterol (Tchol), high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), and triglycerides were documented. Results: After total splenectomy, hyperlipidemia ensued with cholesterol-reducing chow. Tchol, LDL, VLDL, triglycerides, and HDL changed from 56.4 +/- 9.2, 24.6 +/- 4.7, 9.7 +/- 2.2, 48.6 +/- 11.1, and 22.4 +/- 4.3 mg/dL to 66.9 +/- 11.4, 29.9 +/- 5.9, 10.9 +/- 2.3, 54.3 +/- 11.4, and 26.1 +/- 5.1 mg/dL, respectively. Upper pole preservation inhibited abnormalities of Tchol, HDL, VLDL, and triglycerides, and LDL decreased (23.6 +/- 4.9 vs. 22.1 +/- 5.1, P = 0.002). Higher concentrations were triggered by splenectomy and cholesterol-enriched diet (Tchol 59.4 +/- 10.1 vs. 83.9 +/- 14.3 mg/dL, P = 0.000), and upper-pole preservation diminished without abolishing hyperlipidemia (Tchol 55.9 +/- 10.0 vs. 62.3 +/- 7.8, P = 0.002). Conclusions: After splenectomy, hyperlipidemia occurred with both diets. Preservation of the upper pole tended to correct dyslipidemia in modality A and to attenuate it in subgroup B. (c) 2008 Wiley-Liss, Inc. Microsurgery 29:154-160, 2009.

Experimental multivisceral xenotransplantation

Background: Organ shortage impairs the proposition of multivisceral transplantation to treat multiple organ failure. Interspecies (xeno) transplantation is a valid solution for organ shortage; however, suitable models of this advance are lacking. We describe an effective model of multivisceral xenotransplantation to study hyperacute rejection. Methods: Under general anesthesia, we in block recovered the distal esophagus, stomach, small bowel, colon, liver, pancreas, spleen, and kidneys from donors and implanted heterotopically in the lower abdomen of recipients. Animals were divided into four groups: I-canine donor, swine recipient (n = 6); II - swine donor, canine recipient (n = 5); III-canine donor, canine recipient (n = 4); and IV-swine donor, swine recipient (n = 5). Groups I and 11 comprised experimental (xenotransplantation) and III and IV control groups (allotransplantation). During the experiment, we appraised recipient evolution and graft modification by sequential biopsy up to 3 h. At this time, we killed animals for autopsy (experimental end point). Results: We accomplished all experiments successfully. Every grafts attained customary appearance and convenient urine output immediately after unclamp. Around 15 min after reperfusion, xenografts achieved signs of progressive hyperacute rejection and absence of urine output. At the end of experiments we observed moderate to severe hyperacute rejection at small bowel, colon, mesenteric lymph node, liver, spleen, pancreas, and kidney, while stomach and esophagus achieved mild lesions. In contrast, allograft achieved normal or minimum ischemia/reperfusion injury and constant urine output. Conclusion: The present procedure assembles a simple and effective model to study multivisceral xenotransplantation and may ultimately spread researches toward hyperacute rejection.

DNA damage and repair in leukocytes of melanoma patients exposed in vitro to cisplatin

Resistance to chemotherapeutic drugs can be an obstacle to a successful treatment of cancer patients in part associated with individual response and differences in the DNA repair system. The Comet assay is an informative test to investigate DNA damage and repair in cells in response to a variety of DNA-damaging agents, including chemotherapeutic drugs. The aim of this study was to assess leukocytes damage after in-vitro cisplatin treatment and DNA repair action using the Comet assay in 20 patients with melanoma and 20 cancer-free individuals. Leukocytes` DNA damage before and after cisplatin treatment, in three different concentrations, was analyzed. The DNA repair capability was investigated after 1-5 h of in-vitro cells growing without cisplatin. The Comet score of the patients` basal DNA damage was higher than that observed in controls, but the difference was not statistically significant (P=0.85). Although both groups had similar Comet scores to all cisplatin concentrations tested and the DNA repair times, the basal DNA damage (P < 0.001) and cisplatin damages (P < 0.005) were statistically lower than the different repair times investigated. Considering the progressive increase in the Comet score due to repair time, the negative results here observed could be associated with the reduced cell culture incubation that should be better evaluated. Considering the mutagenic action of cisplatin on tumor cells and the importance of individual DNA repair mechanisms in the chemotherapeutic melanoma treatment, the peripheral leukocytes could be particularly useful as a tool for DNA repair response identified by the Comet assay. Melanoma Res 21:99-105 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Influence of Suture on Peripheral Nerve Regeneration and Collagen Production at the Site of Neurorrhaphy: An Experimental Study

BACKGROUND: Restoration of nerve continuity and effective maintenance of coaptation are considered fundamental principles of end-to-end peripheral nerve repair. OBJECTIVE: To evaluate the influence of the number of stitches on axonal regeneration and collagen production after neurorrhaphy. METHODS: Thirty male Wistar rats were equally divided into 3 groups and were all operated on with the right sciatic nerve exposed. In 2 groups, the nerve was sectioned and repaired by means of 3 (group B) or 6 (group C) epineurium sutures with 100 monofilament nylon. One group (group A) was used as a control. Each animal from groups B and C underwent electrophysiological evaluation with motor action potential recordings before nerve section and again at an 8-week interval after neurorrhaphy. Nerve biopsy specimens were used for histomorphometric assessment of axonal regeneration and quantification of collagen at the repair site. RESULTS: Animals from group C had significantly lower motor action potential conduction velocities compared with control animals (P = .02), and no significant difference was seen between groups B and C. Parameters obtained from morphometric evaluation were not significantly different between these 2 groups. Type I collagen and III collagen in the epineurium were significantly higher in group C than in either the control group (P = .001 and P = .003) or group B (P = .01 and P = .02). No differences were identified for collagen I and III in the endoneurium. CONCLUSION: Using 6 sutures for nerve repair is associated with worse electrophysiological outcomes and higher amounts of type I and III collagen in the epineurium compared with control. Neurorraphy with 6 stitches is also related to a significant increase in epineurium collagen I and III compared with 3-stitch neurorraphy.

Histologic Study of Perifascial Areolar Tissue Implanted in Rabbit Vocal Folds: An Experimental Study

Objectives: Perifascial areolar tissue (PAT) consists of loose areolar tissue with viscoelastic properties that are similar to those found in tissues in the superficial layer of the vocal fold. The aim of this study was to quantify the inflammatory process and the collagen content of the graft, as well as that of the host tissue, after placement of a strip of PAT into the rabbit vocal fold. Methods: Surgeries were performed on 30 rabbits. The grafts were implanted in pockets that were surgically created in the right vocal fold. The left vocal fold (control group) was subjected only to surgical manipulation. The animals were divided into 3 groups for evaluations at 15 days, 3 months, and 6 months, and their larynx tissues were subsequently reviewed by histology. Results: The grafts were characterized by disorganized and thick collagen bundles and were identified in all study groups. The collagen density stayed constant over time. There was an acute inflammatory response induced by the graft at 15 clays that did not exist in the specimens taken at 3 and 6 months. Deposition of collagen fibers in the lamina propria was observed starting at 15 days after the operation and was more intense in the experimental vocal fold than in the control vocal fold. Conclusions: Our findings indicated that PAT has a low tendency for promoting an inflammatory response. However, there was a loss of the original architecture of the graft tissue and a greater deposition of collagen in the implanted vocal folds than in the control group.

Potentializing the effects of GM1 by hyperbaric oxygen therapy in acute experimental spinal cord lesion in rats

Study design: Experimental, controlled, animal study. Objectives: To evaluate the effect of GM1 ganglioside, hyperbaric oxygen and both in combination, in the treatment of experimental spinal cord lesions in rats. Setting: Brazil. Methods: Thirty-two Wistar rats with spinal cord lesions were divided into four groups: one group received GM1 ganglioside, one was submitted to hyperbaric oxygen therapy (HBOT), the third received both treatments and the fourth received no treatment (control). Results: There were no significant differences between the groups in the histological analysis, for any of the variables (necrosis, hemorrhage, hyperemia, cystic degeneration, P>0.06). Neither were there any significant differences in the comparison of left and right sides in the functional tests (P>0.06 for all). No significant differences were found in the locomotor ratings, in the comparison of groups at 2, 7, 21 and 28 days after the surgical procedure. However, in the evaluation on day 14, group 3, which received the combined therapy, showed a significantly higher Basso Beattie and Bresnahan score than the other groups (P = 0.015). Conclusion: The therapeutic effect of GM1 in locomotor evaluation of rats submitted to spinal cord lesion is anticipated by HBOT. Spinal Cord (2010) 48, 808-813; doi:10.1038/sc.2010.37; published online 27 April 2010