Siting, design and operational controls for snow disposal sites.

The Municipality of Anchorage (MOA), at 61 degrees north latitude, ploughs and hauls snow from urban streets throughout the winter, incorporating grit and chloride applied to street surfaces for traffic safety. Hauled snow is stored at snow disposal facilities, where it melts at ambient spring temperatures. MOA studies performed from 1998 through 2001 show that disposal site melt processes can be manipulated, through site design and operation practices, to control chloride and turbidity in meltwater. An experimental passive "V-swale" pad configuration tested by MOA investigators reduced site meltwater turbidity by an order of magnitude (to about 50 NTU from the 500 NTU typical of more conventional planar pad geometry). The MOA has developed new siting, design and operational criteria for snow disposal facilities to conform to the tested V-swale pad configuration.

Minimal residual disease in patients with hairy cell leukemia in complete remission treated with 2-chlorodeoxyadenosine or 2-deoxycoformycin and prediction of early relapse.

The purine nucleoside analogues 2-chlorodeoxyadenosine (2-CdA) and 2'-deoxycoformycin (2'-DCF) induce complete remission (CR) in the majority of patients with hairy cell leukemia. However, minimal residual disease (MRD) has been detected in bone marrow core biopsies using immunohistochemical techniques in patients achieving CR by conventional criteria. This study was designed to compare the prevalence of MRD with each agent in patients in CR by using conventional criteria and the relapse-free survival for patients with and without MRD. Bone marrow biopsies from 39 patients treated with a single cycle of 2-CdA and 27 patients treated with multiple cycles of 2'-DCF were studied. The monoclonal antibodies anti-CD20, DBA.44, and anti-CD45RO were used to evaluate the paraffin-embedded bone marrow core biopsies for MRD. Five of 39 patients (13%) treated with 2-CdA had MRD, as compared to 7 of 27 patients (26%) treated with 2'-DCF (two-tailed P = 0.21). Relapse has occurred in two of the five patients with MRD after 2-CdA treatment and in four of the seven patients with MRD after 2'-DCF treatment. In total, 6 of the 12 patients (50%) with MRD have relapsed, whereas 3 of 54 patients (6%) without MRD have relapsed, and 2 patients have died without evidence of relapse. The estimated 4-year relapse-free survival among patients with MRD is 55% (+/- 15%, SE), compared to 88% (+/- 5%, SE) among patients without MRD (two-tailed P = 0.0023). The prevalence of MRD detected in a subset of patients in CR after either 2-CdA or 2'-DCF treatment did not differ significantly. However, the presence of MRD is associated with an increased risk of relapse.

Colorectal polyps with extensive absorptive enterocyte differentiation: histologically distinct variant of hyperplastic polyps.

BACKGROUND: The histologic classification of colorectal polyps is well established. However, practicing pathologists may still occasionally encounter colorectal polyps that are difficult to classify. We studied 6 colorectal polyps that showed uncommon histologic features that have not been described in the English language literature. MATERIALS AND METHODS: The polyps were studied using standard hematoxylin-eosin stain, mucin histochemistry, and electron microscopy. RESULTS: The 6 polyps we studied showed extensive papillary and villous structures with alternating villi and crypts. The villi were lined by well-differentiated absorptive cells, whereas the crypts were lined by immature glandular cells, thus mimicking the histology of the small intestinal mucosa. CONCLUSIONS: These polyps appear to represent a variant of the hyperplastic polyp, in as much as cellular maturation (immature glandular cells differentiate into the mature surface absorptive cells) is the essential feature distinguishing hyperplastic polyps from adenomas.

Bcl-2 and bax protein expression in indolent versus aggressive B-cell non-Hodgkin's lymphomas.

Bcl-2 and bax are cellular proteins that are important in the regulation of apoptosis. Overexpression of bcl-2 protein is associated with prolonged cell survival, whereas overexpression of bax correlates with increased apoptosis after injury. It has been suggested that the ratio of bcl-2 and bax determines a cell's susceptibility to apoptosis. We studied bcl-2 and bax expression by immunohistochemical methods in 46 cases of B-cel non-Hodgkin's lymphoma characterized by the Revised European-American Lymphoma (REAL) classification to determine whether expression of these two proteins correlated with the histological subtype or the predicted clinical behavior (indolent v aggressive). For each case, both the percentage of cells staining as well as the intensity of staining of bcl-2 and bax were recorded, and a bcl-2-bax protein ratio (BBPR) was calculated. Bax staining was identified in 100% of the lymphomas studied. In contrast, bcl-2 staining was seen in only 67%. Bcl-2 expression correlated with the subtype of lymphoma with positive staining in 100% of small lymphocytic lymphomas, 80% of follicle center lymphomas, 38% of diffuse large cell lymphomas, 33% of high-grade B-cell Burkitt's-like lymphomas, 0% of Burkitt's lymphomas, and 0% of B-cell lymphoblastic lymphomas. The BBPR of indolent lymphomas (mean, 1.8) was significantly greater than the BBPR of aggressive lymphomas (mean, 0.6) (P < or = .002). This suggests that bax and bcl-2 expression may be linked to biological behavior in non-Hodgkin's B-cell lymphomas.

CD23 expression in transformed small lymphocytic lymphomas/chronic lymphocytic leukemias and blastic transformations of mantle cell lymphoma.

The immunophenotypic marker, CD23, has been shown to be a useful marker for the distinction of small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) from mantle cell lymphoma (MCL). The usefulness of this marker has not previously been analyzed in distinguishing various "large cell" transformations of SLL/CLL from blastic transformations of MCL (MCL-B). Thirteen cases of transformed SLL/CLL and six cases of MCL-B were analyzed for expression of CD23, either by flow cytometry of peripheral blood, bone marrow, or fresh tissue or by immunoperoxidase staining of paraffin-embedded archival tissue. All of the 13 cases of transformed SLL/ CLL expressed CD23 and all of the 6 cases of MCL-B were negative for CD23. Therefore, CD23 is retained in transformed SLL/CLL. It is a useful marker in distinguishing transformed SLL/CLL from MCL-B and thus might aid in distinguishing those cases that present de novo without a previous diagnosis of SLL/CLL or MCL.

Minimal residual disease may predict bone marrow relapse in patients with hairy cell leukemia treated with 2-chlorodeoxyadenosine.

Minimal residual disease (MRD) can be detected in bone marrow core biopsies of patients with hairy cell leukemia (HCL) after treatment with 2-chlorodeoxyadenosine (2-CdA) using immunohistochemical (IHC) techniques. The purpose of this study was to determine whether the presence of MRD predicts bone marrow relapse. We studied paraffin-embedded bone marrow core biopsies from 39 patients with HCL in complete remission (CR) 3 months after a single cycle of 2-CdA. Biopsies performed 3 months posttherapy and annually thereafter were examined by routine hematoxylin and eosin (H&E) staining and IHC using the monoclonal antibodies (MoAbs) anti-CD45RO, anti-CD20, and DBA.44. At 3 months after therapy, 5 of 39 (13%) patients had MRD detectable by IHC that was not evident by routine H&E staining. Two of the five patients (40%) with MRD at 3 months have relapsed, whereas only 2 of 27 (7%) patients with no MRD and at least 1 year of follow up relapsed (P = .11). Over the 3-year follow-up period, two additional patients developed MRD. Overall, three of six (50%) patients with MRD detected at any time after therapy have relapsed, whereas only 1 of 25 (4%) patients without MRD has relapsed (P = .016). These data suggest that the presence of MRD after treatment with 2-CdA may predict relapse.