Surgical margin in hepatic resection for colorectal metastasis: a critical and improvable determinant of outcome.

OBJECTIVE: To update the analysis of technical and biologic factors related to hepatic resection for colorectal metastasis in a large single-institution series to identify important prognostic indicators and patterns of failure. SUMMARY BACKGROUND DATA: Surgical therapy for colorectal carcinoma metastatic to the liver is the only potentially curable treatment. Careful patient selection of those with resectable liver-only metastatic disease is crucial to the success of surgical therapy. METHODS: Two hundred forty-four consecutive patients undergoing curative hepatic resection for metastatic colorectal carcinoma were analyzed retrospectively. Variables examined included sex, stage of primary lesion, size of liver lesion(s), number of lesions, disease-free interval, ploidy, differentiation, preoperative carcinoembryonic antigen level, and operative factors such as resection margin, use of cryotherapy, intraoperative ultrasound, and blood loss. RESULTS: Surgical margin, number of lesions, and carcinoembryonic antigen (CEA) levels significantly control prognosis. Patients with only one or two liver lesions, a 1-cm surgical margin, and low CEA levels have a 5-year disease-free survival rate of more than 30%. Disease-free interval, original stage, bilobar involvement, size of metastasis, differentiation, and ploidy were not significant predictors of recurrence. The pattern of failure correlates with surgical margin. Routine use of intraoperative ultrasound resulted in an increased incidence of negative surgical margin during the period examined. CONCLUSIONS: Surgical resection or cryotherapy of hepatic metastasis from colorectal cancer is safe and curable in appropriately selected patients. Biologic factors, such as number of lesions and carcinoembryonic antigen levels, determine potential curability, and surgical margin governs the patterns of failure and outcome in potentially curable patients. Optimization of selection criteria and surgical resection margins will improve outcome.

Gastrointestinal hemorrhage after combined percutaneous angioplasty of aortic coarctation and valvuloplasty of aortic stenosis in an infant.

Gastrointestinal hemorrhage has not been previously reported as a complication of dilating left-sided obstructive lesions. This report describes an infant who developed significant intestinal bleeding after combined angioplasty for aortic coarctation and valvuloplasty for aortic stenosis.

Technical and biological factors in disease-free survival after hepatic resection for colorectal cancer metastases.

Careful patient selection for hepatic resection of colorectal cancer metastases is essential to improve current poor results. Carcinoembryonic antigen level and number of metastases were significant preoperative prognostic indicators of 5-year disease-free survival in patients selected clinically for hepatic surgery. Surgical margin, weight of hepatic tissue resected, carcinoembryonic antigen level, and flow cytometry were significant postoperative prognostic indicators. Patients with a carcinoembryonic antigen level less than 200 ng/mL, 1-cm surgical margins, and less than 1,000 g of liver tissue removed had a greater than 50% estimated 5-year disease-free survival rate. If the metastases were diploid on flow cytometry, an additional survival advantage may have been gained. Inadequate surgical margins led to high rates of liver-only recurrence. Nonhepatic recurrence was unrelated to surgical margins. Intraoperative liver examination by ultrasound during primary colon cancer resection and adjuvant chemotherapy may offer earlier selection of biologically appropriate patients and improved outcome; both recommendations require clinical trials.

Use of an intravascular endoprosthesis (stent) to establish and maintain short-term patency of the ductus arteriosus in newborn lambs.

The feasibility of stenting the ductus arteriosus with a balloon-expandable vascular endoprosthesis was tested in 8 newborn lambs. Tantalum wire and stainless steel mesh coronary stents were implanted antegrade or retrograde by percutaneous transfemoral catheterization. One lamb died during the procedure from perforation of the aorta. In 7 lambs, the ductus arteriosus was crossed using endhole catheters and wires, and stents mounted on angioplasty catheters were expanded in the ductus arteriosus. Six lambs had successful implantation and had maintained a sizeable patent ductus arteriosus at 2 h. We conclude that the feasibility of percutaneous stenting of the newborn ductus was demonstrated. By providing patency of the ductus arteriosus, stents may offer nonsurgical alternatives for palliation of cyanotic congenital heart disease and hypoplastic left heart syndrome.

DNA histogram debris theory and compensation.

In this paper we describe a theory of DNA histogram debris generation and compensation that can be applied to paraffin-embedded frozen tissue preparations. The theory predicts the distribution of fragments generated from single and multiple random sectioning of three-dimensional ellipsoids representing nuclei. The fragment distribution is assumed to be a major component of the underlying debris in DNA histograms. A comparison of S-phase fractions (SPF) from matched tissue prepared by frozen and formalin-fixed paraffin-embedded DNA methods demonstrates the usefulness of the theory.

A simple and rapid method for determining the linearity of a flow cytometer amplification system.

We describe a simple and rapid method for determining the linearity of a flow cytometer amplification system. The method is based on a fundamental characteristic of linear amplifiers: The difference between two amplified signals increases linearly with increasing amplifier gain. Two populations of beads or cells, differing slightly in fluorescence intensity, are analyzed by the flow cytometer at increasing photomultiplier tube high-voltage settings. The distribution of the populations' mean difference versus mean position is a straight line intersecting the origin for linear amplifiers. Although some types of nonlinearities cannot be detected with this technique, deviations from linearity indicate nonlinear components in the flow cytometer amplification system. The correlation coefficient is used to quantify degree of nonlinearity. We also describe a method for amplifier nonlinearity compensation.

The significance of ductal shunting during extracorporeal membrane oxygenation.

The purpose of this study was to evaluate the significance and direction of shunts at the level of the foramen ovale or ductus arteriosus in full-term newborns with neonatal respiratory failure who were placed on extracorporeal membrane oxygenation (ECMO). A decrease in left ventricular dimension was expected when infants were placed on ECMO but did not occur. A left-to-right shunt was demonstrated at the ductal level in nine of 12 infants early in the course of ECMO before pulmonary resistance decreased. Presumably, the lack of change in the left ventricular dimension when infants were placed on bypass was due to a left-to-right shunt at the ductal level with ductal flow replacing the right heart output, being drawn into the bypass circuit.

Effects of several commonly used fixatives on DNA and total nuclear protein analysis by flow cytometry.

Five commonly used fixatives (AZF, B-5, Bouin's, formalin, and Zenker's) were evaluated for their effect on the flow cytometric analysis of DNA and total nuclear protein (TNP) in solid tumors. Data were obtained with the use of colonic adenocarcinoma, squamous carcinoma of the lung, mammary adenocarcinoma, and spleen with a plasma cell leukemic infiltrate. The parameters examined were G0-G1 DNA staining intensity, %G0-G1, percent coefficient of variation (%CV), percent debris, and TNP staining intensity. The results showed that variations in the fixation of solid tumor significantly affected flow cytometric-derived parameters. In this study, paraffin-embedded tissue (PET) fixed in 10% (v/v) neutral buffered formalin (NBF) produced the best results, with a %CV below 4.7, whereas fixatives such as Zenker's and B-5 produced poor %CVs (above 6.0) or uninterpretable TNP and light scatter data. These data suggest that a portion of all tissue samples be fixed in NBF to allow for subsequent analysis by fixative-sensitive assays such as DNA in situ hybridization and flow cytometry.

Localization of monoclonal B-cell populations through the use of Komogorov-Smirnov D-value and reduced chi-square contours.

In this study three different flow cytometric analysis techniques are woven together into a single system that permits improved detection of small percentages of monoclonal B cells in a milieu of either normal blood leukocytes or bone marrow cells. This analysis is an extension of the concept of clonal excess, which is used to detect the presence of a tumor that is a clonal expansion of B cells expressing either kappa or lambda light chains. The technique also utilizes "multiple listmode processing," which is defined in this context as the simultaneous analysis of two or more listmode files that share one or more common parameters. This type of data structure enables the segmentation of two parameter light scatter displays into regions from which numerous kappa and lambda histograms subsequently can be analyzed for their respective Komogorov-Smirnov D-values or R-values (reduced chi-square value). The final technique makes use of a calculated parameter display system. Superimposed on the light scatter dot density plot are D-value or R-value contours. The contours target the location of the population that is abnormal, thus providing information for setting optimal bitmap gates for clonal excess studies, other phenotypic analyses, or cell sorting. In experiments using model systems, the sensitivity of this assay is estimated to be between 0.25% and 2.5%. The technique's distribution information and sensitivity may prove useful for staging, treatment monitoring, and relapse detection of B-cell leukemia and lymphoma. This application illustrates the potential of combining multiple listmode processing and calculated parameter display to expand the effective dimensionality of listmode data.

Effect of an inhibitor of DNA methylation on T cells. I. 5-Azacytidine induces T4 expression on T8+ T cells.

Maturing thymocytes express a series of cell surface glycoproteins which can be identified by monoclonal antibodies. The stage II or common thymocyte expresses the phenotype T4+T8+T6+T3-. In response to unknown signals, but presumably involving interactions with products of the major histocompatibility complex, the thymocyte suppresses either the T8 or T4 gene, becoming committed to the T4+T8- or T4-T8+ phenotype. With maturation, the thymocyte also becomes T6-T3+. To study whether DNA methylation may be involved in regulating expression of these determinants in mature T cells, we treated cloned interleukin 2-dependent T8- and T4-bearing T cells with 5-azacytidine (5-azaC), a nucleoside analog which inhibits methylation of newly synthesized DNA. In this report, we show that T8+ T cells treated with 5-azaC express the phenotype T8+T4+T6-T3+. Treatment of the same cells with hydroxyurea, an inhibitor of DNA synthesis, failed to induce T4 on T8+ cells. These results suggest that expression of the T4 gene may be suppressed by DNA methylation in mature T8+ cells.

Definite vs adjuvant radiotherapy. Comparative effects on lymphocyte subpopulations in patients with head and neck squamous carcinoma.

The recent association of alterations in T-lymphocyte subpopulations and impaired cellular immunity prompted an investigation of the effects of radiotherapy (RT) on serial levels of lymphocyte subsets in 30 patients with head and neck squamous carcinoma. Percentage and absolute levels of T3, T4, T6, T8, T10, T11, and Leu 7 cells were measured before, during, and after RT at monthly intervals for six months and compared with levels in 40 normal subjects. Sixteen patients received curative and 14 postoperative adjuvant RT. Before treatment, mean subset levels were similar among the patient and normal groups except for elevated Leu 7 (natural killer) cells in patients with stage I and II disease. There were profound decreases in absolute levels of each subpopulation during and after RT. The percentage of T4 (helper/inducer) cells decreased, whereas that of T8 (cytotoxic/suppressor) and Leu 7 cells tended to increase. Compared with normal values, the mean T4/T8 ratio decreased significantly by six months after RT, when absolute levels of the subsets had rebounded to pretreatment levels in the definitive RT group but remained profoundly decreased in the adjuvant group. The differing recovery patterns suggest that factors other than RT may contribute to persistent immunosuppression following RT.

Flow cytometric analysis of DNA in diagnostic cytology.

Flow cytometric analysis of nuclear DNA content and cell surface immunologic phenotyping were used in the evaluation of cytologic samples obtained from four patients. In each sample, a lymphoid cell population was present, which was difficult to evaluate by traditional cytopathologic methods. In two of the cases, the flow cytometric demonstration of monoclonal populations of lymphoid cells characterized by abnormal amounts of nuclear DNA gave support to the cytologic interpretation of malignancy. In a third sample, a lymphoid cell population that could not be cytologically distinguished from malignant lymphoma cells of small lymphoid cell type was shown to be composed of euploid, polyclonal cells. In the fourth case, the demonstration of euploidy in morphologically distinctive cell populations was helpful in interpreting the fine-needle aspirate of the thyroid gland. The authors conclude that flow cytometry can be used to great advantage in the evaluation of cytologic samples as well as in predicting biologic behavior.

In vitro immune modulation by thymosin alpha 1 in patients with head and neck squamous cell carcinoma.

To determine if patients with head and neck squamous cell carcinoma represent an appropriate population for immune reconstitution with thymosin alpha 1, leukocyte migration inhibition (LMI) in response to phytohemagglutinin was measured in 24 previously untreated patients with head and neck cancer, and the in vitro effects of thymosin alpha 1 on migration inhibition were assessed. Compared to normal subjects, LMI was impaired in the head and neck cancer patients. Thymosin alpha 1, in vitro, was associated with improvement in LMI in the cancer patients. Improvements in migration response with thymosin alpha 1 appeared to be independent of levels of various T-lymphocyte subpopulations. However, patients with a normal LMI response had lower suppressor/cytotoxic cell levels than normal subjects or patients with impaired LMI. The findings confirm prior reports of the effects of thymic hormones on lymphokine production in vitro and provide rationale for further clinical studies of thymosin alpha 1 in patients with head and neck squamous cell carcinoma.