In-vitro model for bacterial growth inhibition of compartmentalized infection treated by an ultra-high concentration of antibiotics

BACKGROUND

Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) are common pathogens encountered in infected cardiovascular-implantable electronic device (CIED). Continuous, in-situ targeted, ultra-high concentration antibiotic (CITA) treatment is a novel antibiotic treatment approach for localized infections. CITA provides sufficient local antibiotic concentrations to heavily infected cavities while avoiding systemic toxicity.

AIM

In-vitro confirmation of the efficacy of the CITA treatment approach in simulated compartmentalized infections.

MATERIALS AND METHODS

A rapid automated bacterial culture analyzing system) Uro4 HB&L™ (was applied to compare the efficacy of selected antibiotics at a standard minimal inhibitory concentration (1MIC), 4MIC, and CITA at 103MIC, for growth inhibition of high bacterial loads (106 colony-forming-units/ml) of ATCC strains of P. aeruginosa, E. coli, and S. aureus.

RESULTS

The addition of gentamicin and amikacin at 1MIC concentrations only temporarily inhibited the exponential growth of E. coli and P. aeruginosa. 4MIC level extended the delay of exponential bacterial growth. Increasing concentrations of vancomycin similarly temporarily delayed S. aureus growth. All tested antibiotics at CITA of 103MIC totally inhibited the exponential growth of the tested bacteria through 72 hours of exposure. (P<0.001).

CONCLUSION

In this in-vitro model, CITA at 103MIC effectively inhibited exponential bacterial growth of high loads of P. aeruginosa, E. coli, and S. aureus. This model offers preliminary laboratory support for the benefit of the in-situ antibiotic treatment, providing ultra-high concentrations directly at the compartmentalized infection site, not achievable by the conventional intravenous and oral routes.

Human Oral Mucosal Stem Cells Reduce Anastomotic Leak in an Animal Model of Colonic Surgery

BACKGROUND

Anastomotic leak is regarded as one of the most feared complications of bowel surgery; avoiding leaks is a major priority. Attempts to reduce or eliminate leaks have included alternate anastomotic techniques. Human oral mucosa stem cells (hOMSC) are self-renewing and expandable cells derived from buccal mucosa. Studies have shown that hOMSC can accelerate tissue regeneration and wound healing. The objective of this study was to evaluate whether hOMSC can decrease anastomotic leak rates in a murine model of colon surgery.

METHODS

Two experiments were performed. In the first study, mice underwent colonic anastomosis using five interrupted sutures. hOMSC (n = 7) or normal saline (NS; n = 17) was injected into the colon wall at the site of the anastomosis. To evaluate whether hOMSC can impact anastomotic healing, the model was stressed by repeating the first experiment, reducing the number of sutures used for the construction of the anastomosis from five to four. Either hOMSC (n = 8) or NS (n = 20) was injected at the anastomosis. All mice that survived were sacrificed on postoperative day 7. Anastomotic leak rate, mortality, daily weight, and daily wellness scores were compared.

RESULTS

In the five-suture anastomosis, there were no differences in anastomotic leak rate, mortality, or daily weight. Mice that received hOMSC had significantly higher wellness scores on postoperative day 2 (p < 0.05). In the four-suture anastomosis, there was a significant decrease in leak rate (70% [NS] vs. 25% [hOMSC], p = 0.029) and higher wellness scores in mice that received hOMSC (p < 0.05).

CONCLUSION

Our study suggests that injecting hOMSC at the colonic anastomosis can potentially reduce anastomotic leak and improve postoperative wellness in a murine model of colon surgery.

A T Drain Approach to Anastomotic Leaks: Another Important Tool in the General Surgeon's Armamentarium

BACKGROUND

Following an intestinal anastomotic leak, stoma creation may be the safest approach. However, this method may be challenging and cause significant morbidity. In selected cases, a T drain approach can be beneficial and a stoma can be avoided.

OBJECTIVES

To present one group's experience with a T drain approach for anastomotic leaks.

METHODS

Data on patients who underwent emergent re-laparotomy following gastrointestinal anastomotic leaks were retrieved retrospectively and assessed with a new intra-operative leak severity score.

RESULTS

Of 1684 gastrointestinal surgeries performed from 2014 to 2018, 41 (2.4%) cases of anastomotic leaks were taken for re-laparotomy. Cases included different sites and etiologies. Twelve patients were treated with a T-tube drain inserted through the leak site, 18 had a stoma taken out, 6 re-anastomosis, 4 were treated with an Endosponge, and one primary repair with a proximal ileostomy was conducted. T drain approach was successful in 11 of 12 patients (92%) with full recovery. One patient did not improve and underwent reoperation with resection and re-anastomosis. A severity score of anastomotic integrity is provided to help surgeons in decision making.

CONCLUSIONS

A T drain approach can be an optimal solution in selected cases following an intestinal anastomotic leak. When the leak is limited, the remaining anastomosis is intact and the abdominal environment allows it, a T drain can be used and a stoma can be avoided.

Altered Expression of the Dna Mismatch Repair Proteins Hmlh1 and Hmsh2 in Cutaneous Dysplastic Nevi and Malignant Melanoma

Molecular alterations in the mismatch repair system suggest that this mechanism may be important in the evolution of cutaneous melanoma. Our current study evaluated the expression of two mismatch repair proteins, hMLH1 and hMSH2, in dysplastic nevi (DN) and cutaneous melanoma (CM). Immunohistochemical staining of these proteins was performed on 55 CM and 30 DN specimens. The staining results were divided into three groups: negative, partially positive and strongly positive. Normal adjacent skin cells served as an internal control for positive immunostaining. Altered immunoreactivity of one of the proteins was found in four (13.4%) DN and seven (12.7%) CM. Lack of staining for hMLH1 was observed in two (6.7%) cases of DN and five (9.1%) cases of CM; staining for hMSH2 was absent in two (6.7%) of the DN and two (3.6%) of the CM specimens. Partially positive staining was found in 33.3% and 53.3% for hMLH1 and hMSH2, respectively, in DN, and in 54.5% and 69.1%, respectively, in CMM. Our study shows that complete or partial loss of MMR protein expression occurs in a subset of both DN and CM and may represent a distinct pathway in the development of some DN and CM.

A surgical solution to regain bowel continuity following an extended left colectomy-reviving and extending the indication for a "Flip-Flop" procedure

BACKGROUND AND AIMS

Extended left hemicolectomy might be necessary for several indications. Once the resection is completed, it would be difficult or impossible to anastomose the transverse colon to the rectum due to the difficulty in mobilizing the transverse colon to reach for a tension-free rectal anastomosis. The aim of this report is to present the "Flip-Flop" technique to overcome this challenging situation. The procedure is based on a surgical technique published in the early 1960s to avoid permanent stoma after proctectomy and consists of changing the location of the right colon to reach the rectum.

METHODS

Clinical parameters, surgical aspects, and postoperative outcome of patients that underwent the flip-flop procedure following an extended left colectomy in our medical service was reviewed.

RESULTS

Three patients underwent a flip-flop procedure after an extended left colectomy performed for various reasons. The surgical technique is detailed in a step by step manner. Patients had uneventful postoperative recovery with an adequate functional outcome.

CONCLUSIONS

We believe that this approach should be revived and be considered also in cases when the full length of the rectum is preserved to avoid ileo-rectal anastomosis or a high-tension colocolonic anastomosis. Popularization of this surgical solution among surgeons is highly important.

[LAPAROSCOPIC APPROACH AND SURGICAL CONSIDERATIONS IN RESECTION OF A LARGE EPIPHRENIC ESOPHAGEAL DIVERTICULUM]

Epiphrenic diverticulum of the esophagus is an uncommon finding. Small diverticula are usually asymptomatic in nature. Large diverticula may present with dysphagia, chest or upper abdominal discomfort, vomiting, irritating cough or halitosis. There are a few different surgical approaches to epiphrenic diverticulum resection. It can be performed with an abdominal or a thoracic approach and in an open or a laparoscopic manner. In this case report we present a 70 years old male patient with a giant epiphrenic diverticulum and dysphagia. The patient was operated upon via a laparoscopic abdominal approach with intra-operative endoscopic assistance and underwent a diverticulum resection. We present a review of the different kinds of esophageal diverticula, the mechanism of their formation, and the surgical considerations associated with choosing the appropriate surgical approach.

Evaluation of peritoneal CEA levels following colorectal cancer surgery

BACKGROUND

Peritoneal carcinoembryonic antigen (pCEA) levels in the early postoperative period following a curative resection of colorectal cancer (CRC) have not been previously studied.

METHODS

Postoperative peritoneal fluids of 36 CRC patients followed by 24 benign colonic disease patients were evaluated for CEA levels and tumor cell presence. Serum CEA levels were also evaluated prior and after surgery.

RESULTS

Although high postoperative pCEA levels were observed in some benign patients, more CRC patients exhibited significant elevation of postoperative pCEA (>5 ng/ml) compared to benign patients (50% vs. 23%, P = 0.039). Postoperative median pCEA levels of CRC patients were significantly higher compared to benign patients (5.4 vs. 2 ng/ml, P = 0.011). Specifically, pCEA levels in CRC patients were significantly elevated when measured during the first 24 hr after surgery. Postoperative pCEA levels were associated with colon tumor location compared to rectal location. However, no correlation was found with known risk factors for cancer recurrence or with serum CEA levels.

CONCLUSIONS

Postoperative pCEA levels may be significantly elevated following a curative resection for CRC. Its significance within patient's prognostic evaluation remains to be studied. Inclusion of patient's follow-up data may reveal the significance of elevated pCEA levels following CRC resection.

[Laparoscopic management of peritoneal dialysis catheters]

INTRODUCTION

Peritoneal dialysis (PD) is one of the established methods for the management of patients with end-stage renal failure. Laparoscopy has been used to assist in the insertion of new catheters as well as for the salvage of malfunctioning peritoneal dialysis catheters (PDC).

OBJECTIVES

The purpose of this retrospective study was to review our experience in the utilization of laparoscopy for the management of PDC.

METHODS

We reviewed the charts of all consecutive patients who had undergone either a ap-assisted insertion of a PDC utilizing a modified peritoneoscopic Y-TEC [Medigroup, Inc, Oswego, Ill) technique (YT) under direct laparoscopic vision or laparoscopic-assisted procedures for the salvage of a malfunctioning PD catheter.

RESULTS

Twenty nine patients had undergone 43 procedures that included the insertion of a new PD catheter using the modified YT technique, YT with simultaneous adhesiolysis and omentectomy; YT with repair of an epigastric hernia, omentectomy, adhesiolysis and repositioning of PDC; and ravage and repositioning of the obstructed PD catheter in all patients who needed repositioning of the catheter, the PDC was fixed with an intraperitoneal suture to the lower anterior abdominal wall. Postoperatively, malfunction of the catheter was found in one patient due to reclotting of PDC caused by oozing as a result of extensive adhesiolysis. One patient needed emergent laparotomy due to small bowel perforation that was missed during a difficult laparoscopic adhesiolysis.

CONCLUSIONS

Laparoscopic surgery may be helpfuL for the diagnosis and the management of a malfunctioning PDC. A modified YT technique is safe and may be one of the alternative methods for the placement of a PDC.

Chemopreventive effects of Coltect, a novel dietary supplement, alone and in combination with 5-aminosalicylic acid in 1,2-dimethylhydrazine-induced colon cancer in rats

OBJECTIVES

Coltect is a novel dietary supplement containing curcumin, green tea and selenomethionine. Previous reports have suggested that these agents can prevent colorectal cancer (CRC). The present study examined the chemopreventive effect of Coltect alone or combined with 5-aminosalicylic acid (5-ASA) using the 1,2-dimethylhydrazine (DMH) model in rats.

METHODS

The effect of Coltect was examined on HT-29 CRC cells by growth inhibition assay. Apoptosis was determined by annexin V-FITC/PI staining. Male rats were injected with DMH in vivo and treated with Coltect 150 mg/kg, 5-ASA 50 mg/kg or their combination, by oral gavage. Aberrant crypt foci (ACF) were identified by methylene blue staining.

RESULTS

HT-29 cells exhibited a dose-dependent response to Coltect. Part of the growth inhibition can be explained by the induction of mild-moderate apoptosis in cancer cells (28%) compared with the untreated cells (10%). In the in vivo model, the average number of ACF was divided into small (1-3 crypts) or large (≥4 crypts). The Coltect compound reduced the number of small and large ACF similarly to 5-ASA (40% reduction). This reduction was amplified by combining the two agents (70% reduction).

CONCLUSION

Coltect inhibits the growth of colon cancer cells, induces apoptosis and inhibits ACF development. Furthermore, it augments the growth inhibitory effect of 5-ASA in vivo. This may be clinically important since this safe dietary supplement-drug combination can be administered as a chemopreventive regimen for the treatment of CRC.

Curcumin potentiates the pro-apoptotic effects of sulindac sulfone in colorectal cancer

OBJECTIVE

The use of sulindac sulfone (SFN) for colorectal cancer (CRC) therapy is limited due to its toxicity. The present study was carried out to examine whether curcumin, a novel chemopreventive agent, can potentiate the effects of low dosages of SFN in CRC treatment.

METHODS

HT-29 CRC cells were exposed to SFN (200 - 400 microM), curcumin (5 - 10 microM) or their combination. The cytotoxic effects of the drugs were evaluated using growth inhibition assays. Annexin V/PI and cell cycle analysis were employed to study the mechanism of action of the drugs. The therapeutic efficacy of the drugs in vivo was examined using the aberrant crypt foci (ACF) model. The treatment groups included eight rats/group.

RESULTS

Treatment of cells with curcumin and SFN resulted in a synergistic inhibitory effect of 50 - 90% (p < 0.005) on cell growth. Growth inhibition was associated with inhibition of proliferation, G2/M arrest and induction of apoptosis. Administration of curcumin (0.6%) and SFN (0.06%) to 1, 2-dimethylhydrazine treated rats significantly reduced (by 75%, p < 0.01) the number of ACF.

CONCLUSIONS

Curcumin augments the therapeutic effects of SFN. This may be clinically important since the addition of curcumin to low dosages of SFN may encourage a safer and potent combinatorial treatment regimen for CRC.

Young-age onset of colorectal cancer in Israel

AIM

The study was conducted to investigate the differences in clinical-pathological, ethnic, and demographic presentations and the expression of mismatch repair proteins in a cohort of young-onset (</=50 years) versus late-onset Israeli patients (>50 years) with colorectal cancer.

MATERIALS AND METHODS

Clinical, demographic, and histopathological data of patients with colorectal cancer were collected retrospectively from medical records and pathology reports.

RESULTS

Ninety patients, 50 years of age or younger with a mean age of 42 years were compared with a group of 190 patients above 50 years of 50 (see Table 1). Sixty percent of the young-onset patients were females, compared to 40% in the older age group (P = 0.02). Twenty-one percent of the young-onset patients were Arabs as compared to 2% of older-onset patients (P = 0.001). Younger patients displayed a higher percentage of mucinous cancers and a higher percentage of diagnosis at an advanced stage of disease; 40% of young-onset versus 31% of older-onset patients presented Duke's stages C and D (P = 0.02).

CONCLUSIONS

Younger age of onset colorectal cancer in our cohort of Israeli patients is associated with higher percentage of Arab patients, mucinous cancers, female gender, and advanced stage at diagnosis.

Celecoxib and curcumin additively inhibit the growth of colorectal cancer in a rat model

BACKGROUND

Multiple studies have indicated that specific COX-2 inhibitors may prevent CRC. However, the long-term use of COX-2 inhibitors is not toxicity-free and may be limited due to its cardiovascular side effects. The present study was carried out to examine the chemopreventive effects of celecoxib and curcumin alone and in combination using the 1,2-dimethylhydrazine (DMH) rat model.

METHODS

Male rats were injected with DMH and randomly divided into four groups that consumed one of the following diets: (a) AIN-076 control diet; (b) AIN-076/curcumin (0.6%); (c) AIN-076/celecoxib (0.16%), or (d) AIN-076/celecoxib (0.16%) and curcumin (0.6%). Aberrant crypt foci (ACF) were identified by intensive staining with methylene blue in comparison to the surrounding normal crypts.

RESULTS

The average number of ACF per rat colon was 64.2 +/- 3 in the control group, 39 +/- 5 and 47 +/- 10 for the curcumin- and celecoxib-treated group, respectively, and 24.5 +/- 6 in the group that had received both agents.

CONCLUSIONS

In vivo, curcumin augments the growth inhibitory effect of celecoxib. This may be clinically important as this dose of celecoxib can be achieved in human serum following standard anti-inflammatory dosing of 100 mg.

Specimen length as a perioperative surrogate marker for adequate lymphadenectomy in colon cancer: the surgeon's role

The objective of this study was to determine whether there is a correlation between the length of the sigmoid colon removed and the number of harvested lymph nodes (LNs). Pathology charts of 137 sigmoid resections that were done over a 5-year period were reviewed. The length of removed sigmoid specimen reported in the pathology reports was correlated with the number of LNs retrieved from the specimen. The mean and median numbers of retrieved LNs were 9 and 10, respectively. There was an increase in the number of retrieved LNs with increasing length of resected sigmoid colon. For Dukes' B patients, the average length of the resected specimen was 15.1 cm for those with < 12 LNs and 20.3 cm for those with > 12 LNs (P = 0.01). Our data suggest that the surgeon may play an important role in determining the extent of LN harvesting during large bowel resection for cancer.

Predominance of younger age, advanced stage, poorly-differentiated and mucinous histology in Israeli Arab patients with colorectal cancer

BACKGROUND

Colorectal cancer (CRC) incidence in the Israeli population is higher in the Jewish population than among Arabs.

MATERIALS AND METHODS

To determine the differences in demographic, clinical, histopathological and molecular characteristics of CRC between these two ethnic groups, 125 Arab patients treated at 3 community hospitals over a 20-year period were compared to a group of 208 consecutive Jewish patients. The mutator (replication error-positive [RER]) phenotype was detected by immunohistochemical evaluation of hMLH1 and hMSH2 protein expression in tumor tissue.

RESULTS

The Arab patients were younger than the Jewish patients with a higher percentage of poorly-differentiated and mucinous cancers and a higher percentage of advanced stage cancers (Dukes' C+D) at presentation. The mutator phenotype was detected at similar rates in both ethnic groups.

CONCLUSION

Our study demonstrated that CRC patients from two major ethnic populations in Israel, Arabs and Jews, differed in terms of the prevalence of the disease, pathological features and age at presentation, but not in frequency of mismatch-repair-positive cancers.

Perioperative Management of Patients Undergoing Elective Colorectal Surgery in Israel: A National Survey

BACKGROUND

The approach to perioperative antibiotic prophylaxis, bowel preparation, and postoperative routines in elective colorectal resections has changed over the last two decades. The aim of this national survey was to document the current methods of perioperative management of those patients scheduled for elective colorectal resections in surgical departments in Israel.

METHODS

A mail and telephone survey of surgical departments was conducted in 2001 in order to evaluate the routines of perioperative management of elective colorectal resections. Re-evaluation was performed in 2004.

RESULTS

In 2001, all but one of the responders used low-residue diet preoperatively and combined oral and parenteral antibiotic prophylaxis. Polyethylene glycol or sodium phosphate bowel preparation was used by 69% of the responders. The most common oral regimens were a combination of neomycin plus metronidazole (43.5%) or neomycin plus erythromycin (47.8%). The most common parenteral regimens used were gentamicin plus metronidazole or gentamicin plus metronidazole plus ampicillin (56.5% and 17% of the responders, respectively). Cephalosporins alone or in combination were used in three departments. In 17 departments (74%), parenteral prophylactic antibiotics were continued for 24 h or longer (up to 72 h). All but one of the departments left a nasogastric tube for 1-5 days after surgery. There were substantial changes over the last three years-that is, less use of preoperative restriction diets, shorter duration of perioperative antibiotic coverage, more common use of cephalosporins, switch to sodium dihydrogen and sodium hydrogen phosphate bowel preparation, shorter use of postoperative nasogastric drainage, and faster resumption of peroral fluids.

CONCLUSIONS

In 2001, the majority of surgical departments in Israel used a conservative approach to perioperative management of patients undergoing elective colorectal resections. Significant changes occurred during the last three years. The perioperative routines used today in most general surgery departments in Israel comply with current recommendations.

Early Postoperative Evaluation of Groins After Laparoscopic Total Extraperitoneal Repair of Inguinal Hernias

BACKGROUND

Minimally invasive laparoscopic total extraperitoneal (LTEP) repair of bilateral and/or recurrent groin hernias has been popularized as one of the procedures of choice in the past decade. The early postoperative course is uneventful in most cases. A few patients, however, will develop temporary postoperative groin swelling. The aim of our study was to evaluate clinical and sonographic findings in the groin during the early postoperative period following LTEP.

METHOD

One hundred and five consecutive patients with primary bilateral (n = 90), recurrent unilateral (n = 12), and primary unilateral (n =3) groin hernias operated on during an 18-month period underwent clinical and sonographic examination two to three weeks after LTEP.

RESULTS

On clinical examination, a localized groin swelling was found in 21 patients (20%). The most frequent sonographic findings were localized groin collections compatible with seroma or hematoma, found in 35 patients (33%). Hypoechoic diffuse tissue swelling around the mesh, lipomas, and residual hernias was found in four patients each (4%). None of the patients with hypoecoic mass had any clinical manifestations postoperatively. Extraperitoneal close suction drains were left for 8-12 hours in 46 patients. The average volume of fluid drained was 62 mL (range, 30-200 mL). There was no correlation between the use of suction drains and the frequency of fluid collections detected on sonography. Cord lipoma was detected postoperatively in four patients and was excised in one using an open anterior approach. Residual or recurrent hernia was detected postoperatively on sonography in four patients, but only one developed a symptomatic and clinically detectable hernia during eight months of follow-up. Overall, postoperative ultrasonographic findings following LTEP repair were found in 37% of patients.

CONCLUSION

Clinical and sonographic findings such as localized fluid collections compatible with seroma or hematoma are common following LTEP. Postoperative suction drains did not reduce the frequency of sonographically detected collections. The clinical relevance of suspected postoperative hernia detected on sonography without clinical manifestations remains uncertain, and has to be determined on long-term follow-up.

Should peritoneal tears be routinely closed during laparoscopic total extraperitoneal repair of inguinal hernias? A reappraisal

BACKGROUND

Peritoneal tears (PTs) are not uncommon during the course of laparoscopic total extraperitoneal (LTEP) repair of groin hernias. Most endoscopic surgeons advocate routine closure of these tears. Our approach is not to perform routine closure of PTs. The aim of this study was to evaluate the possible effect of our approach on the intra- and postoperative course of patients in whom PTs were left opened.

METHODS

Prospective data were collected for LTEP repairs of 298 hernias performed in 166 consecutive patients.

RESULTS

There were 134 primary and 34 recurrent hernias. In 23% of patients, unilateral or bilateral PTs were observed during the course of operation. Of these, the prevalence of tears was 21.8% for primary repair and 41% for recurrent repair. In 40 patients with PTs, the procedure was accomplished successfully laparoscopically. The early postoperative course was uncomplicated in all patients. Results of outpatient follow-up with a mean observation time of 16 months (range, 2-30) did not reveal any complications that could be attributed to PTs.

CONCLUSIONS

These data demonstrate that PTs do not have to be routinely closed and the majority of cases may be safely managed without peritoneal closure. We have not observed any intra- or postoperative complications that could be attributed to peritoneal tears.

Suppressive effect of aspirin on aberrant crypt foci in patients with colorectal cancer

BACKGROUND

and aims: Aspirin and other non-steroidal anti-inflammatory drugs have been shown to reduce the risk of colorectal cancer (CRC). Animal models have shown that aspirin is also effective in reducing the density of aberrant crypt foci (ACF). The aim of the study was to evaluate the effect of chronic administration of aspirin on the distribution pattern and histological characteristics of ACF in patients with CRC.

METHODS

Our study compared the distribution patterns and histomorphological characteristics of ACF between a group of CRC patients treated with low dose aspirin (n=59) and a control group without aspirin (n=135). ACF were visualised on methylene blue stained macroscopically normal mucosa, microdissected, and serially cut.

RESULTS

ACF were found in 75.8% of mucosal samples from the control group and in 36% of mucosal samples from the aspirin treated group, indicating a 47% decline in prevalence of ACF in colonic samples of patients treated with aspirin. A significant reduction from 92.5% to 40% (p<0.0001) was found in distal large bowel samples containing one or more ACF. Similarly, the aspirin treated group showed a reduction in ACF density of 64% and 82%, respectively, in both proximal and distal parts of the colon, indicating a significant reduction in ACF/cm(2) in distal colon samples (p<0.01). The aspirin treated group displayed a 52% reduction in dysplastic ACF although this difference was not statistically significant.

CONCLUSIONS

Our study has provided evidence of the effective chemopreventive action of low dose aspirin on ACF in humans.

Angiogenic switch in earliest stages of human colonic tumorigenesis

BACKGROUND

Angiogenesis is activated in numerous physiological and pathological conditions. We examined whether new vessel formation exists in the earliest stages of colonic tumorigenesis.

MATERIALS AND METHODS

Microvascular density (MVD) was examined in 176 formalin-fixed and paraffin-embedded aberrant crypt foci (ACF) dissected from macroscopically-normal mucosa obtained from patients with colorectal cancer. ACF were classified as non-hyperplastic, non-dysplastic (NH-ACF, n = 80), hyperplastic (H-ACF, n = 72) and dysplastic (D-ACF, n = 24). Mucosal strips were stained with methylene blue solution and screened under x 40 magnification for ACF. The identified ACF were microdissected and stained with an anti-CD-34 monoclonal antibody. MVD in ACF were compared to that of normal corresponding mucosa.

RESULTS

The mean MVD for normal mucosa and ACF were 13.7 +/- 7.7 and 23 +/- 13, respectively. Microvessel counts increased in NH-ACF versus normal mucosa (18.7 +/- 10 vs. 13.7 +/- 7.7, p = 0.05), in H-ACF versus NH-ACF (24.8 +/- 14 vs. 18.7 +/- 10, p = 0.002) and in D-ACF versus H-ACF (31.7 +/- 10 vs. 24.8 +/- 14, p = 0.014). We further evaluated the effect of low-dose aspirin on MVD in ACF. No effect of aspirin on microvessel counts could be detected.

CONCLUSION

Our data suggest that angiogenesis occurs in ACF which are the earliest morphologically identifiable preneoplastic and early neoplastic lesions in colonic mucosa. With progression from NH-ACF to D-ACF there is a progressive, statistically significant increase in MVD, suggesting active angiogenesis during the earliest steps of colorectal tumorigenesis.

Should Aspirin Therapy be Withheld before Insertion and/or Removal of a Permanent Peritoneal Dialysis Catheter?

The necessity of withdrawal of aspirin [acetylsalicylic acid (ASA)] for fear of perioperative or postoperative bleeding in patients about to undergo surgery is as yet controversial. In this study we prospectively evaluated the effect of ASA on postoperative bleeding in end-stage renal failure patients who underwent insertion, removal, and/or replacement of a peritoneal dialysis (PD) catheter at our institution from November 1999 to March 2001. During the study period 52 of the above procedures were consecutively performed in 46 patients. Patients whose catheters were removed as a result of refractory peritonitis were excluded from the study. In all cases the PD catheter used was the coiled two-cuff Tenckhoff (NIPRO™, Manchester, GA) catheter and the surgery was performed in the operating room under local anesthesia. No drains were left in the operating wound. Postoperative bleeding (wound hematoma or persistent oozing from the incision or exit site) was classified as either minor (requiring no professional intervention and/or blood replacement) or major [necessitating blood transfusion (≥1 unit red blood cells). Of the 52 procedures 29 (in 24 patients) were performed while the patient was receiving aspirin at the time of operation (aspirin group). The remaining 23 were without aspirin and constituted the control group. ASA dose was 100 mg/day in all but three who were on buffered ASA (325 mg/day). The groups were well matched with regard to age; sex; mean residual renal function; and preoperative international normalized ratio, activated partial thromboplastin time, and platelet count. In no case was there significant intraoperative bleeding. There were five (17.2%) and three (13.0%) minor bleeds in the aspirin group and control group, respectively. One major bleed occurred in the control group ending in an exploratory laparotomy. Of the nine bleeding complications six were observed after catheter removal. From these data we conclude that PD catheter insertion/removal can be safely performed under conventional low-dose aspirin therapy.

Should aspirin therapy be withheld before insertion and/or removal of a permanent peritoneal dialysis catheter?

The necessity of withdrawal of aspirin [acetylsalicylic acid (ASA)] for fear of perioperative or postoperative bleeding in patients about to undergo surgery is as yet controversial. In this study we prospectively evaluated the effect of ASA on postoperative bleeding in end-stage renal failure patients who underwent insertion, removal, and/or replacement of a peritoneal dialysis (PD) catheter at our institution from November 1999 to March 2001. During the study period 52 of the above procedures were consecutively performed in 46 patients. Patients whose catheters were removed as a result of refractory peritonitis were excluded from the study. In all cases the PD catheter used was the coiled two-cuff Tenckhoff (NIPRO, Manchester, GA) catheter and the surgery was performed in the operating room under local anesthesia. No drains were left in the operating wound. Postoperative bleeding (wound hematoma or persistent oozing from the incision or exit site) was classified as either minor (requiring no professional intervention and/or blood replacement) or major [necessitating blood transfusion (> or = 1 unit red blood cells). Of the 52 procedures 29 (in 24 patients) were performed while the patient was receiving aspirin at the time of operation (aspirin group). The remaining 23 were without aspirin and constituted the control group. ASA dose was 100 mg/day in all but three who were on buffered ASA (325 mg/day). The groups were well matched with regard to age; sex; mean residual renal function; and preoperative international normalized ratio, activated partial thromboplastin time, and platelet count. In no case was there significant intraoperative bleeding. There were five (17.2%) and three (13.0%) minor bleeds in the aspirin group and control group, respectively. One major bleed occurred in the control group ending in an exploratory laparotomy. Of the nine bleeding complications six were observed after catheter removal. From these data we conclude that PD catheter insertion/removal can be safely performed under conventional low-dose aspirin therapy.

Immunoreactivity of p53, Ki-67, and c-erbB-2 in phyllodes tumors of the breast in correlation with clinical and morphologic features

BACKGROUND AND OBJECTIVES

Phyllodes tumor (PT) is a biphasic tumor with unpredictable behavior. Our study aimed to evaluate clinicopathologic factors and biomarkers that may be helpful in predicting the outcome of these tumors.

METHODS

We evaluated immunoreactivity of p53, c-erbB-2, and Ki-67 in 23 PT treated over a 10-year period. The proliferative activity in PT and expression of p53 and c-erbB-2 were correlated with clinicopathologic features of the tumors and patients' outcome.

RESULTS

Positive stromal p53 immunoreactivity was found in PT with atypia, infiltrative borders, high cellularity, as well as in PT that displayed higher then average proliferation index, although none of these parameters reached statistical significance. There was a good correlation between proliferative stromal cell activity expressed Ki-67-labeling index and the malignant features of the tumors. Primary tumors that recurred displayed high proliferative activity. Three of four recurrent tumors showed a progression toward higher malignant phenotype with concomitant increase in proliferative stromal cell activity. c-erbB-2-positive tumors had no particular histologic features or association with either p53 positivity or higher proliferative indices.

CONCLUSIONS

p53 expression tends to be more frequent in PT with higher malignant potential but did not predict recurrence. Incompletely excised tumors that recurred displayed high proliferative activity in their primary tumors. Progression toward more malignant phenotype in the recurrent PT was accompanied with increase in stromal cell proliferative activity, suggesting the presence of biological continuity between benign, borderline, and malignant PT.

Evaluation of putative molecular biomarkers in abdominal and retroperitoneal leiomyosarcomas

AIMS

Leiomyosarcomas (LMS) are diverse tumours with different biological behaviour. To evaluate the biological nature of intraabdominal and retroperitoneal leiomyosarcomas we retrospectively examined the immunoreactivity of p53, bcl-2 and proliferative activity expressed as Ki-67-labelling index in 43 tumours.

METHODS

Immunohistochemical staining was performed using a peroxidase-streptavidin method on paraffin-embedded sections using specific anti- p53, anti- bcl-2 and anti Ki-67 monoclonal antibodies.

RESULTS

Of 43 tumours, seven were located in the stomach, 11 in the small or large bowel, 12 in the uterus, 11 in the retroperitoneum and two cases in the urinary bladder. Five-year disease-free survival was 46.5%. Twenty-three patients (53.4%) died of the disease. Positive immunoreactivity for p53 and bcl-2 was found in 18 (41.9%) and 26 patients (60.5%), respectively. Positive Ki-67 staining was observed in eight patients (18.6%). Proliferative indices were higher in LMS with high mitotic activity (P=0.004) and high grade (P=0.009). All Ki-67 positive LMS were intermediate or high-grade tumours. Ki-67-labelling index showed inverse relationship to bcl-2 expression. A trend towards higher survival and expression of bcl-2, p53 or Ki-67 was found.

CONCLUSIONS

Our results demonstrate that p53 and bcl-2 are expressed in a substantial number of intraabdominal and retroperitoneal leiomyosarcomas. In our study, the expression of these biomarkers did not predict patient outcome. Higher Ki-67 labelling indices were found in more biologically aggressive leiomyosarcomas.

Angiogenesis, p53, and c-erbB-2 immunoreactivity and clinicopathological features in male breast cancer

BACKGROUND AND OBJECTIVES

p53, c-erbB-2, and tumor microvascular density have been shown to be potential prognostic tools in female breast cancer. Our objective was to assess the significance of these biomarkers as prognostic factors in infiltrating male breast cancer.

METHODS

A retrospective study of expression of p53, c-erbB-2, and tumor microvascular density was done on a group of 26 male breast cancer patients. Biotin-streptavidin immunohistochemical study with specific anti-p53, anti-c-erbB-2, and anti-CD34 antibodies was carried out on paraffin sections of breast carcinoma. The data of expression of the biomarkers were merged with clinicopathological data such as tumor grade, T class, TNM stage, estrogen receptor status, tumor recurrence, and patient survival.

RESULTS

p53 and c-erbB-2 were expressed in 46% and 39% of carcinomas, respectively. No correlation was found between positive immunoreactivity of p53, and tumor grade, size, T class, TNM stage, and survival. Nor was any relation found between tumor size, T class, TNM stage, survival, and c-erbB-2 overexpression. c-erbB-2 overexpression was significantly higher in high grade carcinomas. Estrogen receptor (ER) were positive in 21 out of 26 of tumors (81%). No trends were observed between estrogen receptor status and clinicopathological parameters or survival (data not shown). There was a positive correlation between mean microvascular density (MVD), advanced T class, and survival: higher MVD counts were found in patients with advanced tumors and in those who had tumor relapses or died of metastatic disease.

CONCLUSIONS

This study suggests that tumor microvascular density may serve as a potential prognostic tool in male breast carcinoma.

Topoisomerase IIalpha expression in ductal carcinoma in situ of the breast: a preliminary study

Ductal carcinoma in situ (DCIS) of the breast, a precursor lesion of invasive breast cancer, is a heterogeneous disease in terms of histomorphologic features and biologic behavior. Our aim was to assess the proliferative activity, expressed as topoisomerase IIalpha (Topo IIalpha) immunoreactivity and c-erbB-2 expression in relation to morphologic features and architectural pattern of DCIS. The study included 26 DCIS, which were reclassified according to the recommendations of Consensus Conference. Topo-IIalpha and c-erbB-2 immunoreactivity were detected on paraffin sections. Topo IIalpha was consistently negative in normal ductal epithelium. Topo IIalpha-labeling index (Topo IIalpha-LI) was 0.7+/-0.6% for grade I, 4.3+/-3.9% for grade II, and 13.4+/-8.9 for grade III lesions (P<.01). For mixed nuclear grade DCIS, Topo IIalpha-LI was 6.8+/-4.8. There was no difference in Topo IIalpha-LI between different architectural patterns in low- and intermediate-grade lesions. In high nuclear grade DCIS, there was a progressive increase in Topo IIalpha-LI from solid toward cribriform and comedo-type DCIS. Positive c-erbB-2 immunoreactivity was found in 46% of DCIS, being highest in DCIS with high nuclear grade (78%) and in lesions with extensive necrosis. Topo IIalpha-LI was significantly higher in c-erbB-2-positive lesions (Topo IIalpha-LI- 12.4+/-8.5) as compared with negative lesions (Topo IIalpha-LI- 3.9+/-4.5, P<. 0001). Overexpression of c-erbB-2 and Topo IIalpha is associated with poorly differentiated lesions. Proliferative activity in individual ducts of DCIS depended primarily on the nuclear grade and was independent of architectural patterns of individual ducts in architecturally heterogeneous lesions.

Incidence of BRCA1 and BRCA2 mutations in Ashkenazi colorectal cancer patients: preliminary study

BACKGROUND

Mutations in BRCA genes are associated with an elevated incidence of colorectal cancer (CRC). While 20% of CRC patients have a familial history of colonic malignancies, in only 5% is the genetic setting understood. Thus, a majority of these patients lack any known genetic marker. Our aim was to explore the relevance of BRCA mutations to serve as such markers in the genetic screening and counseling of CRC patients.

PATIENTS AND METHODS

136 consecutive Israeli Jewish patients with sporadic CRC were screened for BRCA "Ashkenazi mutations": 185delAG, 5382insC and 6174delT. Carrier status was evaluated employing PCR, restriction analysis, SSCP and a Pronto BRCA kit.

RESULTS

We found one 185delAG and two 6174delT carriers, altogether three Ashkenazi carriers out of 87 Ashkenazi patients tested, 3.5%. No carriers were found among the Arabs and non-Ashkenazi Jews surveyed.

CONCLUSIONS

Our preliminary results show elevated rates of BRCA "Ashkenazi mutations" in Ashkenazi CRC patients, suggesting their involvement in CRC carcinogenesis. An implementation of a wider study will establish the role of these mutations as genetic markers for CRC.

Telomerase activity in ductal carcinoma in situ of the breast

Telomerase plays an important role in maintaining the stability of the chromosomes. Activity of telomerase has been detected in proliferating and immortalized cell lines and in a number of malignant tumors including invasive breast cancer. The aim of the study was to examine telomerase activity in ductal carcinoma in situ (DCIS), which is considered to be a precursor lesion of infiltrating breast carcinoma, using a PCR-based telomerase activity protocol (TRAP). We examined 35 samples obtained from histologically confirmed breast biopsies, including 13 normal breast tissues, 11 infiltrating ductal carcinoma (IDC), nine DCIS, and two DCIS with microinvasion. Telomerase activity was demonstrated in 8/9 samples of DCIS, both samples of DCIS with microinvasion, and all but one sample of IDC. Normal breast tissue had no demonstrable telomerase activity. Our results indicate that telomerase is activated frequently in early breast carcinogenesis, although its utilization as a biomarker in DCIS is questionable.

Oncoprotein coexpression in human aberrant crypt foci and minute polypoid lesions of the large bowel

BACKGROUND

Genetic aberrations observed in the large bowel during the neoplastic progression have a cumulative effect and are responsible for the propagation of the multistep malignant process. In the present study we evaluated the immunoreactivity of c-fos, ras, bcl-2 and p53 in aberrant crypt foci (ACF) and minute polyps of the large bowel obtained from patients with colorectal cancer.

METHODS

ACF and minute polyps were collected from macroscopically normal colonic mucosa. Protein immunoreactivity was detected on parafin sections utilizing the biotin-streptavidin method on 25 hyperplastic, 10 dysplastic ACF, 5 hyperplastic and 10 dysplastic adenomas.

RESULTS

41% of the lesions displayed positive ras immunoreactivity. bcl-2 immunoreactivity was positive in six minute polyps of which five were neoplastic. fos immunoreactivity was detected in five ACF and seven minute polyps, mainly in dysplastic lesions. Two neoplastic polyps were positive for p53 immunoreactivity. Coexpression of two or more oncoproteins was found with increasing frequency in dysplastic versus hyperplastic lesions and in polypoid lesions versus ACF.

CONCLUSION

Abnormal expression and coexpression in oncoproteins can be identified in the earliest stages of colorectal tumorigenesis and may contribute to the progression of selected lesions during ACF-adenoma-carcinoma sequence.

Long-term incidence of acute myocardial infarction after open and transurethral resection of the prostate for benign prostatic hyperplasia

PURPOSE

Acute myocardial infarction was found to be the main cause of increased long-term mortality in patients after transurethral compared to open prostatectomy in various retrospective studies. We performed a randomized prospective study to compare morbidity and incidence of acute myocardial infarction in patients after transurethral compared to open prostatectomy for benign prostatic hyperplasia.

MATERIALS AND METHODS

We studied 365 patients who were assigned to transurethral (236) or open (129) prostatectomy only according to the size of the prostate and who were followed for 7 to 8 years. The clinical status of the patients in both groups before and after the operation was compared, and the rate of myocardial infarction and long-term mortality was studied.

RESULTS

More patients with a history of cerebrovascular accident (5.4 versus 0.8%) and indwelling catheters (16.3 versus 7.6%) before the operation were in the open prostatectomy group. Among the 236 patients operated on transurethrally 31 were reoperated on (6 more than once) during followup compared to 4 of the 129 patients who underwent open prostatectomy. In 15 patients from the transurethral prostatectomy group myocardial infarction developed compared to 9 patients in the open prostatectomy group. This difference was not statistically significant. The rate of acute myocardial infarction after prostatectomy, no matter which approach was used, was greater than 6% and it appeared to be higher when compared to the rate of infarction in the general population of the same age group, which is approximately 2.5% in our county. There was no statistically significant difference in the overall mortality rate between the transurethral and open prostatectomy groups, which was 14.4 and 8.5% respectively.

CONCLUSIONS

Open prostatectomy is more effective in overcoming urinary obstruction than the transurethral approach. No significant differences in myocardial infarction or overall mortality rates were found between the 2 groups.

Controlled release of TGF-beta1 impedes rat colon carcinogenesis in vivo

Transforming growth factor beta1 (TGF-beta1) is a cytokine known to play a key role in the control of cell growth. TGF-beta1 potently inhibits the proliferation of human and rodent-derived epithelial cells. Colonic precancerous and moderately differentiated cancer cells are responsive to TGF-beta1, whereas malignant colon cancer cells are resistant to the inhibitory action of the cytokine. These observations have been derived exclusively from in vitro studies. Therefore, the main aim of our study was to determine whether TGF-beta1 exerts a growth-restraining action on colon carcinogenesis in vivo. TGF-beta1 was sequestered into ethylene acetate copolymer matrices and "loaded" preparations were implanted intraperitoneally (i.p.) in rats. One week later, the animals were treated with dimethylhydrazine (DMH), a colon procarcinogen. Empty matrices devoid of TGF-beta1 but containing bovine serum albumin (BSA) carrier served as the appropriate control preparations. The number of aberrant crypt foci (ACF), considered to be preneoplastic lesions of the colon, was scored. Tumor formation and size were assessed at the appropriate times. TGF-beta1 released in a sustained manner from copolymer matrices: (i) markedly inhibited colonic ACF formation and the number of aberrant crypts and (ii) significantly reduced colonic tumor formation and size.

Chemopreventive effect of aspirin on growth of aberrant crypt foci in rats

Nonsteroidal anti-inflammatory drugs display a chemopreventive effect on polyps and cancer of the large bowel. This study evaluated the inhibitory effect of aspirin on the distribution and growth of aberrant crypt foci (ACF), the earliest putative preneoplastic and early neoplastic lesions in a rat model. For initiation of ACF, Sprague Dawley rats were injected with azoxymethane (30 mg/kg), a well-established rat carcinogen. After the second injection the rats were allocated to three groups, which received 0.2% or 0.6% aspirin or the solvent only (control group). After 6 weeks the animals were killed, and their colons removed, fixed in formalin, and screened for distribution and size of ACF, separately for middle and distal parts of the large intestine. The rats injected with azoxymethane showed a 100% incidence of ACF. Administration of 0.2% and 0.6% aspirin resulted in 55% and 54% reduction, respectively, in overall frequency of ACF. Aspirin significantly reduced the frequency of medium-sized (four to six crypts per focus) and large (three to six crypts per focus) but not the small (one to three crypts per focus) ACF. In the control group the ACF of the same multiplicity were larger than those in the aspirin-treated rats. No statistically significant difference in ACF-inhibiting effect was noted between 0.6% and 0.2% aspirin solution. Aspirin given at a concentration of either 0.2% of 0.6% thus has a chemopreventive effect on ACF, acting on postinitiation stage of azoxymethane-induced colonic carcinogenesis model in rats.

Aberrant crypt foci in human colons: distribution and histomorphologic characteristics

Aberrant crypt foci (ACF) are one of the earliest putative preneoplastic, and in some cases, neoplastic lesions in human colons. These microscopic lesions, identified on methylene blue-stained mucosa with a low-power-magnification microscope, are thought to be closely related to the earliest steps in multistage colonic tumorigenesis. We investigated the distribution pattern and histomorphological features of ACF in 74 patients with sporadic colorectal cancer. The distribution pattern shows a slightly higher prevalence with older age. The prevalence of the ACF in sigmoid colon was significantly higher in patients with colorectal cancer as compared with patients with benign colonic diseases. Also, significantly more ACF were detected in distal parts of the large bowel (descending, sigmoid colon, and rectum) than in proximal parts. Of 42 microdissected lesions, 12 were dysplastic and 30 were hyperplastic foci. The average size of dysplastic lesions was significantly larger than hyperplastic foci. More apoptotic bodies were found in dysplastic lesions. These lesions also showed an upward expansion of proliferative compartment and higher proliferation indices expressed as proliferating cell nuclear antigen-labeling index. Lymphoid follicles were frequently observed in the base of both hyperplastic and dysplastic foci (40% and 66.6%, respectively). The coincidence of lymphoid follicles was 2.5 to 8 times higher than expected. These features may be related to further progression of selected ACF during colorectal tumorigenesis.

Proliferating cell nuclear antigen as a marker of cell kinetics in aberrant crypt foci, hyperplastic polyps, adenomas, and adenocarcinomas of the human colon

BACKGROUND

One of the first steps in multistage colonic carcinogenesis is increased cell proliferation and an upward shift of the proliferation zone of colonic crypts. In the present study, progression in cell kinetics was followed up at all sequential stages of colonic carcinogenesis, starting with aberrant crypt foci (ACF), the earliest putative preneoplastic lesions, hyperplastic and dysplastic polyps, and invasive carcinomas.

MATERIALS AND METHODS

Colonic tissue and tumor specimens were prospectively obtained from 65 patients treated at our hospital for adenocarcinoma or malignant polyps. For identification of ACFs, dissected mucosal strips obtained from patients with colorectal cancer were stained with 0.1% methylene blue and scanned under dissecting microscope. Paraffin-embedded ACFs and macroscopic lesions were serially sectioned, deparaffinized, and stained with a monoclonal antiproliferating cell nuclear antigen (PCNA) antibody. The PCNA-labelling index (PCNA-LI), expressed as a ratio of positively stained nuclei to total nuclei counted, was calculated separately for basal, middle, and upper colonic crypt compartments. A comparison of the PCNA-LI was made for each compartment in normal mucosa, and hyperplastic and dysplastic lesions.

RESULTS

A stepwise increase in the PCNA-LI was observed during neoplastic progression of colonic lesions. The two most important variables of increased cell proliferation, expressed as PCNA-LI per crypt compartment, were the presence of dysplasia and the size of dysplastic lesions.

CONCLUSIONS

In colorectal carcinogenesis, hyperproliferation with upward expansion of proliferative compartment is a characteristic feature at all stages of malignant progression.

Physiologic human T-cell responses to OKT3 in the human peripheral blood lymphocyte-severe combined immunodeficiency mouse model

BACKGROUND

Our goal was to study physiologic responses of human T lymphocytes to OKT3 in the human peripheral blood lymphocyte-severe combined immunodeficiency (hu-PBL-SCID) mouse model.

METHODS

SCID mice were pretreated with anti-asialo-GM1 (alpha-ASGM1) and radiation, then engrafted with human peripheral blood lymphocytes (PBLs). Seven to 14 days after engraftment, when most human T cells in the spleen of these mice are CD3+/CD4+ and CD3+/CD8+, mice were treated with OKT3 or control antibody. Mice were killed for histopathologic examination, for flow cytometric assessment of the engrafted human lymphocytes, and for analysis of human tumor necrosis factor-alpha serum levels.

RESULTS

Intravenous injection of 5 microg of OKT3 resulted in early antigenic modulation of engrafted human T lymphocytes, with the emergence of CD3-/CD4+ and CD3-/CD8+ cells in the spleen of hu-PBL-SCID mice. There was an increase in the serum concentration of human tumor necrosis factor-alpha within 4 hr after OKT3 injection, suggesting early T-cell activation. Antigenic modulation and activation of the human lymphocytes in the spleen was followed by their depletion within 24 hr. This human T-cell response to OKT3 in hu-PBL-SCID mice is analogous to the response in humans treated with OKT3 and in BALB/c mice injected with an anti-murine CD3 monoclonal antibody. Graft-versus-host disease in the mice was abrogated by OKT3 treatment, and OKT3-treated mice lived longer than controls. Histopathologic studies showed clearance of lymphocytic infiltration in the liver and lungs of OKT3-treated mice.

CONCLUSIONS

These findings provide further evidence of functional human immune T cells in the hu-PBL-SCID mouse. This model may have useful applications in the study of transplantation immunology.

Natural history of aberrant crypt foci. A surgical approach

BACKGROUND

The aberrant crypt focus (ACF) appears to be an important early step in colorectal carcinogenesis. Our objectives were to determine the natural history of ACF in a surgical model.

METHODS

The natural history of ACF was followed by marking the lesions in vivo with tattoos. Rats were given four weekly injections of azoxymethand (AOM; 20 mg/kg). One hundred days after the first injection of AOM, rats were anesthetized, and individual aberrant crypt focus was identified by staining with methylene blue. A 3 x 3 mm area, identifying one large (4-8 crypts) ACF was marked with a tattoo dye in each colon. Control animals received saline or AOM injections and were tattooed in areas without ACF. At 200 days, colons were examined for the presence of macroscopic lesions.

RESULTS

A total of 54 tumors were found in the study group of 38 animals, and 21 of these were in the transverse and proximal descending colon. The marked areas (all in transverse and proximal descending colon) yielded 6 tumors and 2 ACF, but in 30 instances no abnormality was noted. Probability of observing a tumor in the 3 x 3 mm area of the colon that was identified as containing ACFs was 17 times greater than expected from the observed tumor rate in approximately the same zone (16 vs. 1.7 percent; 95 confidence interval, 10 to 22 and 0.5 to 1.3 percent). Twenty control animals receiving saline had no tumors of epithelial origin. Nine control animals that were carcinogen-treated and tattooed in areas without ACF had no tumors in the marked areas.

CONCLUSION

Results thus show regression of many ACF identified early in the carcinogenesis process. Results also support the hypothesis that some ACF are precursor lesions for adenomas and cancers.

Cytotoxicity of B72.3XOKT3 bispecific antibody recognizing human colon cancer

Bispecific monoclonal antibodies can be used to redirect peripheral blood lymphocytes against tumor cells. In the present study, a murine bispecific monoclonal antibody was developed using somatic hybrydization. The antibody has two different binding arms: one arm directed against human CD3 receptor expressed on T-lymphocytes and the other against tumor associated glycoprotein TAG-72, expressed on human carcinomas, such as colon, breast, and pancreas. Partially purified antibody was capable of inducing human T-cell proliferation and preventing growth of colon cancer cell line in nu/nu mice in a tumor neutralization assay.

Mastectomy as the preferred treatment for breast cancer among new immigrants from the former USSR

Sixty-four new immigrant patients with primary breast cancer who arrived in Israel since 1990 were compared to 322 Israeli women with primary breast cancer. New immigrant patients had a more advanced stage at diagnosis (stage III+IV 28% vs. 13% respectively, P = 0.00005); larger mean tumor size (3.08 +/- 1.7 cm vs. 2.25 +/- 1.4 cm respectively, P = 0.00002); and more involved lymph nodes (3.8 +/- 5.3 vs. 1.8 +/- 3.3 P = 0.0002). Forty-seven percent of new immigrants had breast-conserving surgery compared to 69% of the Israelis (P = 0.0004). In stage II 51% of the new immigrants had conservative surgery compared to 74% in the Israeli group (P = 0.03). Mastectomy was recommended to 39 Israeli patients and to six immigrants. Only 19% of the Israeli group requested mastectomy compared to 44% in the new immigrant group. Most of the new immigrant patients chose mastectomy although breast-conserving surgery was an equal alternative. The reasons for choosing mastectomy as the preferred mode of treatment were related to economic problems, different life concepts, and other priorities. Constant surveillance and considerable enlightenment are needed in the new immigrant population, so that they will be able to separate the disease and its treatment from their paramedical problems.

Acute cholecystitis in diabetic patients

Postoperative outcome and severity of acute cholecystitis in 32 diabetic patients (DM) who underwent urgent cholecystectomy were compared on a case-control basis with 32 nondiabetic age/sex matched controls. There was no difference in incidence of renal and lung diseases or duration of acute symptoms before surgery. Cardiovascular diseases were more often seen in the diabetic group (16/32 in DM, 7/32 in controls, P = 0.03). Bactobilia was more often in diabetics (19 in DM, 11 in controls, p = 0.07). Postoperatively, there was a trend toward higher incidence in overall complication rate. Infectious complications (wound and respiratory infections, hepatic abscess) were higher in DM, although the difference was not statistically significant. One patient in DM group died as a result of multiorgan failure. There was no difference in total and postoperative hospital stay. The severity of acute cholecystitis was greater in diabetics (26 patients with moderate-to-severe cholecystitis in DM group, 18 in control group, P = 0.05). The study indicates that although pathological findings were more severe in DM group, the postoperative course is comparable in diabetics as compared to age and sex matched nondiabetic controls. Our findings justify reconsideration of prophylactic cholecystectomy in asymptomatic diabetic patients.

A human model of xenogeneic graft-versus-host disease in SCID mice engrafted with human peripheral blood lymphocytes

Despite previous attempts there is currently no suitable animal model available for xenogeneic graft versus host disease (XGVHD) mediated via human immunocompetent cells. Recently, we have developed an efficient protocol to engraft SCID mice with human peripheral blood lymphocytes (Hu-PBLs). The engraftment efficiency is extremely high, such that 100% of Hu-PBL-SCID mice die of XGVHD within 4 weeks after engraftment with Hu-PBLs (3-5 x 10(7) cells). A series of experiments was performed to investigate the mechanisms involved in the severe XGVHD. The results suggest that XGVHD was induced by human CD4+ T cells, antixenogeneic (antimouse) antibodies, and lymphokines. The SCID mouse model will be extremely valuable for the evaluation and development of immunosuppressive agents and transplantation protocols for human XGVHD.