Energy consumption as a predictor test of the durability of a biological tissue employed in cardiac bioprosthesis.

The mechanical behavior of the young bull pericardium in a fatigue test has been studied. This material is a similar tissue to those used in valve leaflet construction for a cardiac bioprosthesis. The consumed energy on each test was evaluated and afterwards used as a predictor of the biomaterial strength. Two-hundred and nine samples were tested to cyclical fatigue. The cut-off point to determine the sample quality was whether or not they resisted at least 4500 cycles. Only 22 samples withstood over that point (10.52%). The samples were classified according to their fatigue behavior in excellent, undefined and unsuitable. By using as a reference the consumed energy in the first 25 cycles, we could distinguish correctly (between 93.2 and 96.1%) the unsuitable material and most of the excellent (between 78.1 and 95.2%). From the rejected material 77% was really detachable and from the accepted, only 50% was excellent, with an equal methodology. The receiver operating characteristics curve was employed to establish decision levels when selecting samples, being 0.85 the best area (theoretical maximum value of 1). It is concluded that the energy wasted is a good predictor of the strength of the tissue. More than 90% of the unsuitable material and 50% of the excellent material (5% of all the material) is detected with this method.

The clinical utility of Tc-99m sestamibi scintimammography in detecting multicentric breast cancer.

The ability to recognize multicentric breast cancer preoperatively would assist in identifying appropriate candidates for breast conservation surgery. Tc-99m scintimammography (SMM) is an adjunct to conventional mammography in identifying selected patients with breast cancer. The purpose of this study is to report the utility of SMM in identifying patients with multicentric breast cancer. Breast cancer patients treated by mastectomy who underwent a preoperative SMM between 1992 and 1999 were identified using the institution's Tumor Registry. The pathology report of each patient was reviewed for multicentric disease defined as an additional focus of cancer within a different quadrant of the breast or greater than 2.5 cm from the dominant tumor mass. Each patient's preoperative SMM was reviewed and compared with the pathologic findings to obtain correlative data. Fifty-eight women treated by mastectomy had preoperative SMM (age range 35-78 years; median 52 years). Pathology revealed infiltrating ductal carcinoma in 49 patients (84.5%), infiltrating lobular carcinoma in five patients (8.6%), ductal carcinoma in situ in three patients (5.1%), and colloid carcinoma in one patient (1.7%). Multicentric disease was present in the specimens of eight patients for a prevalence of 10.3 per cent. SMM was positive for uptake in 36 of 58 patients (sensitivity 62.1%). The sensitivity, specificity, positive predictive value, and negative predictive value of SMM in the detection of multicentric disease were 62.5, 96, 71, and 94 per cent, respectively. Although the overall sensitivity of SMM in the detection of breast cancer is superior to that of conventional mammography and physical examination in identifying multicentric breast cancer it is not an accurate modality for detecting multicentric disease in this study group. However, it may have limited applications in specific cases.

Patterns of recurrence in anal canal carcinoma.

HYPOTHESIS: The initial modality of treatment of anal canal carcinoma (ACC) influences the pattern of recurrence of disease. DESIGN: A retrospective analysis comparing patterns of recurrence in patients with ACC undergoing either surgery or chemoradiotherapy as their initial therapeutic intervention. Anal margin cancers and adenocarcinomas were excluded. SETTING: A university-affiliated urban medical center. PATIENTS: Eighty-one patients were given a diagnosis of ACC between February 1, 1952, and December 31, 1998. Fifty-one (63%) of the patients initially underwent surgery: abdominoperineal resection in 38 patients (75%) and local excision in 13 patients (25%). Chemoradiotherapy was the initial therapeutic intervention in 30 patients (37%). MAIN OUTCOME MEASURES: The patterns of recurrence (local vs distant disease) and survival were compared between the group that underwent palliative surgery (hereafter referred to as the surgical group) and the group that received chemoradiotherapy (hereafter referred to as the chemoradiotherapy group). RESULTS: The mean follow-up was 40 months. Local recurrence occurred in 7 patients (14%) in the surgical group vs 7 patients (23%) in the chemoradiotherapy group (P =.46). Using Kaplan-Meier actuarial analysis, local recurrence rates for the surgical and chemoradiotherapy groups at 1 year were 0% and 6%, respectively (P =.32), and at 5 years were 17% and 36%, respectively (P =.02). The average (+/-SD) time to local recurrence in the surgical group was 23 +/- 0.7 months and for the chemoradiotherapy group 16 +/- 2.9 months (P =.27). Five (71%) of the 7 patients with local recurrences in the chemoradiotherapy group underwent salvage abdominoperineal resection with 100% disease-free survival at a mean follow-up of 35 months. When patients presenting with metastatic disease were excluded, distant recurrences developed in 7 patients (16%) in the surgical group and 2 (7%) in the chemoradiotherapy group (P =.31). Actuarial 5-year distant recurrence rates for the surgical and chemoradiotherapy groups were 26% and 19%, respectively (P =.65). Five-year survival was 42% in the surgical group and 74% in the chemoradiotherapy group (P =.01). CONCLUSION: There was a higher rate of local recurrence in patients with ACC treated with chemoradiotherapy vs surgical resection as the initial therapeutic intervention. However, when this occurred, abdominoperineal resection was effective salvage therapy and was associated with a 100% disease-free survival at 3 years. Therefore, chemoradiotherapy is justified as the initial treatment for ACC and has an overall 5-year survival that is significantly higher than that attained with initial surgical treatment.

Keratinocyte growth factor ameliorates dextran sodium sulfate colitis in mice.

Keratinocyte growth factor (KGF) is emerging as an important mediator of mucosal defense and repair in the colon. The aim of the present study was to evaluate and further characterize the effects of exogenous KGF administration utilizing the dextran sodium sulfate (DSS) model of colitis in mice. Colitis was induced via oral administration of DSS (5 g/100 ml) to Balb/c mice for eight days. Intraperitoneal administration of KGF (5 mg/kg, once daily) or vehicle (VEH) was initiated 1 hr prior to the induction of the colitis (N = 10, each group). Mucosal injury of the entire colon was histologically assessed and graded. An approximately fourfold reduction in the crypt damage score was noted in the KGF group when compared to controls (VEH) (2.8 +/- 1.03 and 11.4 +/- 0.78, respectively). The significant reduction of mucosal injury in KGF treated mice confirms that KGF is a key mediator maintaining the integrity of the colonic mucosa.

Keratinocyte growth factor promotes healing of left-sided colon anastomoses.

BACKGROUND: Inadequate healing and consequent leakage from bowel anastomoses are a significant cause of postoperative morbidity and mortality. Systemic application of keratinocyte growth factor (KGF) has been shown to promote mucosal healing in models of colitis in rats and mice. The aim of the present study was to evaluate the effect of systemic KGF administration on healing of colonic anastomoses in rats. METHODS: Rats underwent laparotomy, division of the left colon, and sigmoido-sigmoidostomy. KGF (5 mg/kg) or vehicle were administered intraperitoneally in two groups (n = 30 per group) 12 hours prior to surgery, and then once daily until sacrifice (6 animals per group; 2, 4, 7, 12, and 21 days after surgery). Bursting pressure measurements, histologic evaluation, morphometric analysis, mucin and collagen staining, and hydroxyproline measurements of the anastomotic site were performed. RESULTS: Administration of KGF significantly increased anastomotic bursting pressure on postoperative days 2, 4, and 7 by 34%, 49%, and 19%, respectively. Histology, mucin staining, and measurements of the colonic crypt depth showed markedly less extended inflammation with an increased acidic mucin content and a significantly thickened mucosal layer in the KGF treated group when compared with vehicle-treated animals. CONCLUSIONS: KGF promotes healing of colonic anastomoses in rats during a 1-week postoperative period following large bowel surgery. KGF may be acting to accelerate host reparative processes as well as to enhance protection of the anastomotic wound bed by increased colonic epithelium proliferation, increased mucus production, and reduction of the inflammatory activity at the anastomotic site.

Scintimammographic analysis of nonpalpable breast lesions previously identified by conventional mammography.

BACKGROUND: In randomized trials, screening mammography has led to decreased mortality from breast cancer. However, the low positive predictive value of mammography (i.e., the proportion of patients with a positive test result who actually have breast cancer) results in a large number of unnecessary biopsies. We determined whether scintimammography with technetium-99m-sestamibi is a useful supplemental diagnostic tool for women with nonpalpable breast abnormalities identified by conventional mammography. METHODS: Scintimammography was performed preoperatively on 70 women who were 31-66 years of age (mean age and median age = 51 years). These women had nonpalpable breast abnormalities identified by conventional mammography; subsequently, a needle-localization excisional biopsy of each suspicious lesion was performed. Scintimammographic images were interpreted independently by two nuclear medicine physicians who were blinded to all clinical and pathologic data, and an interobserver variation analysis was performed. RESULTS: Interobserver variation analysis of the scintimammographic findings showed an agreement for breast diagnosis of 97% and a kappa coefficient of 0.90. Comparison of scintimammographic findings and histopathologic results revealed that the sensitivity (proportion of patients with breast cancer who had a positive test result), the specificity (proportion of patients without breast cancer who had a negative test result), the positive predictive value and the negative predictive value (proportion of patients with a negative test result who actually did not have breast cancer) of scintimammography were 56% (95% confidence interval [CI] = 23%-85%), 87% (95% CI = 75%-94%), 38% (95% CI = 15%-68%), and 93% (95% CI = 82%-98%), respectively. Four of nine breast cancers were not detected by scintimammography. CONCLUSION: Because of excellent interobserver agreement, scintimammography provides an objective way of detecting primary breast carcinoma. In view of its low sensitivity and positive predictive value, however, scintimammography is not currently recommended as a screening test in patients with nonpalpable positive mammographic findings.

Immunohistologic assessment of technetium-99m-MIBI uptake in benign and malignant breast lesions.

UNLABELLED: This study was undertaken to assess the relationship between the degree of 99mTc-MIBI uptake in breast lesions and the following histologic factors: neovascularity, desmoplastic reaction, cellular proliferation and mitochondrial density. METHODS: Forty-two patients who previously underwent MIBI breast imaging (4 false-negative, 12 false-positive, 15 true-negative, 11 true-positive) were studied. Immunohistochemical staining was performed for neovascularity (Factor VIII antigen), desmoplasia (alpha-actin antigen), mitochondrial density (mitochondrial antigen) and cellular proliferation (MIB-1 antigen). The degree of microscopic staining was correlated with region of interest measurements of MIBI uptake on scintigraphy. RESULTS: There was a poor correlation between MIBI uptake and the degrees of neovascularity (r = 0.08, p > 0.05) and intracellular mitochondrial density (r = 0.04, p > 0.05) while there was a moderate correlation with cellular proliferation (r = 0.4, p < 0.05) and desmoplasia (r = 0.55, p < 0.001). CONCLUSION: The degree of MIBI uptake in breast lesions is multifactorial, but it appears to be related more to the degree of desmoplastic activity and cellular proliferation than neovascularity and mitochondrial density.

[Keratinocyte growth factor significantly improves healing of left-sided colon anastomoses]. / Keratinozyten-Wachstumsfaktor verbessert signifikant die Heilung von linksseitigen Kolonanastomosen.

Inadequate healing and consequent leakage from large bowel anastomoses are a significant cause of morbidity and mortality following large bowel surgery. Systemic application of KGF has been shown to promote mucosal healing in models of colitis in rats and mice. The aim of the present study was to evaluate the effect of systemic Keratinocyte Growth Factor (KGF) administration on healing of colonic anastomoses in rats. Sprague-Dawley rats underwent laparotomy, division of the left colon and sigmoideo-sigmoideostomy. KGF (5 mg/kg) or its vehicle were administered intra-peritoneally 12 hours prior to surgery, and then once daily until sacrifice (2, 4, 7, 12 and 21 days after surgery). Bursting pressure measurements, histologic evaluation, morphometric analysis, mucin and collagen staining and hydroxyproline measurements of the anastomotic site were performed. Administration of KGF significantly increased anastomotic bursting pressure on postoperative day 2, 4 and 7 by +34%, +49% and +19%, respectively but not on day 12 and day 21. Histology, mucin staining and measurements of the colonic crypt depth showed markedly less extended inflammation, increased acidic mucin content and a significantly thickened mucosal layer in the KGF treated group when compared to vehicle treated animals. Hydroxyproline content and collagen staining were not different between KGF and vehicle treated animals. We conclude that KGF promotes healing of colonic anastomoses in rats during a one week postoperative period. KGF may be acting to accelerate host reparative processes as well as to enhance protection of the anastomotic wound bed by increased epithelium proliferation, increased mucus production and reduction of the inflammatory activity at the anastomotic site.

Detection of axillary lymph node metastasis of breast carcinoma with technetium-99m sestamibi scintimammography.

Several investigators have advocated management of breast cancer patients without axillary dissection, obviating the morbidity associated with this procedure. Approximately 30-40 per cent of all patients with breast carcinoma will have lymph node metastasis. Axillary dissection offers no therapeutic benefit to node-negative patients, and it may lead to unnecessary morbidity. It is apparent that a noninvasive test to determine the presence of axillary metastases may obviate the need for axillary dissection. The aim of this study was to determine the role of scintimammography (SMM) with technetium-99m sestamibi in the detection of axillary node metastasis in breast carcinoma. Thirty-one women with the diagnosis of breast carcinoma who had SMM and axillary lymphadenectomy were included. SMM was done following an intravenous injection of 20 mCi of Tc-99m sestamibi. Planar scintigraphic imaging was acquired in a lateral prone and an anterior view of the breasts for the evaluation of the axilla. SMM scans were interpreted by two nuclear medicine physicians blinded to the clinical presentation and histologic results. The correlation of SMM with histologic assessment showed a sensitivity of 75 per cent, specificity of 82 per cent, positive predictive value of 88 per cent, and negative predictive value of 64 per cent. The interobserver correlation of SMM interpretation between the two nuclear medicine physicians showed good agreement, with kappa = 0.49. Consistency in the interpretation of Tc-99m SMM was obtained when two independent radiologists reviewed the studies. Based on these data, we are unable to show that SMM is a reliable test for the detection of axillary metastases in patients with breast cancer. However, a high positive value of 88 per cent is encouraging and deserves further study.

A forty-year experience with anal carcinoma: changing trends and impact of multimodality therapy.

Anal canal carcinoma is a rare clinical entity accounting for 1 to 3 per cent of all gastrointestinal malignancies. Abdominoperineal resection used to be the primary modality of treatment. However, recurrence rates of 20 to 40 per cent were observed after this mutilating procedure. In recent years, multimodality therapy with radiation and chemotherapy has shown at least equal results with the intention to preserve sphincter function. The objective of this study is to describe our experience at Harbor-UCLA Medical Center during the past 4 decades (1955-95), emphasizing changes in demographics, clinical presentation, and impact of multimodality therapy. Seventy-eight patients with the diagnosis of anal canal carcinoma were included. A steady increase in the incidence of anal carcinoma in younger people was observed (24% less than 64 years old for the 1955-65 period versus 75% for 1986-95 period). A female predominance was found in 1955-65 period, with F:M ratio 1.5, and a majority of male cases was seen in the last period (1986-95). Abdominoperineal resection was the preferred treatment during 1955-65, whereas during 1986-95 chemoradiation was the treatment of choice. We observed a trend from primary surgical treatment toward chemoradiotherapy with improvement in survival and preservation of ano-rectal function. Since 1988, we have not performed an abdominoperineal resection for primary treatment of anal carcinoma. Survival analysis was made grouping the patient population according to primary treatment. Higher survival rates were observed in the groups that received chemoradiotherapy (P = 0.0368) either as adjuvant or primary therapy. Chemoradiotherapy should be recommended as primary therapy to most patients.

Gastric adenocarcinoma in patients 40 years of age or younger.

BACKGROUND: Gastric adenocarcinoma is considered a disease of the middle aged and elderly and has been infrequently reported in patients under 40 years of age. The purpose of this study was to determine the proportion of young patients diagnosed with gastric adenocarcinoma and to compare the demographic, clinical and pathologic features of younger and older patients with gastric adenocarcinoma. METHODS: A retrospective cohort study using tumor registry records of all patients with gastric adenocarcinoma diagnosed from 1982 through 1996 at a public teaching hospital. Demographic, clinical, and pathologic comparisons were made between patients younger than 41 years of age and race- and sex-matched older patients with gastric adenocarcinoma. RESULTS: Thirty of 203 (15%) cases of gastric adenocarcinoma were diagnosed in patients less than 41 years (range 23 to 40). Male to female ratio was 1:1. Young patients were more likely to be black (33% versus 17%, P = 0.04) Both younger and older patients presented with advanced disease, with nearly half of each group having metastases. Twelve of 29 (41%) younger patients were operated on without a histologic diagnosis of gastric adenocarcinoma in contrast to only 1 older patient (P < 0.001). One of 30 (3%) young patients is alive 39 months following gastrectomy. Twenty patients died and the remaining 9 were lost to follow-up, all with known residual or recurrent disease. Six-month survival of young patients (23%) was less than older patients (42%) (P = 0.14). Young patients were more likely to have diffuse histology (80% versus 55%, P = 0.12). Overt infection with Helicobacter pylori was uncommon in both groups. CONCLUSIONS: Young patients accounted for an unusually high proportion of patients with gastric adenocarcinoma diagnosed at our public teaching hospital. Young patients were significantly more likely to be black and less likely to have an accurate preoperative histologic diagnosis. Both young and older patients presented with advanced disease and had poor survival. Young patients were more likely to have diffuse histology and had poorer 6-month survival, suggesting a more aggressive variety of the disease in this group.