Interaction of the novel anthracycline antitumor agent N-benzyladriamycin-14-valerate with the C1-regulatory domain of protein kinase C: structural requirements,isoform specificity,and correlation with drug cytotoxicity

Anthracycline antibiotics like doxorubicin (DOX) are known to exert their antitumor effects primarily via DNA intercalation and topoisomerase II inhibition. By contrast, the noncross-resistant cytoplasmically localizing DOX analogue, N-benzyladriamycin-14-valerate (AD 198), only weakly binds DNA and does not inhibit topoisomerase II, yet it displays superior antitumor activity, strongly suggesting a distinct cytotoxic mechanism. In recent modeling studies, we reported a structural similarity between AD 198 and commonly accepted ligands for the C1-domain of protein kinase C (PKC), and we hypothesized that the unique biological activity of AD 198 may derive, in part, through this kinase. Consistent with this hypothesis, the present biochemical studies demonstrate that AD 198 competes with [3H]phorbol-12,13-dibutyrate ([3H]PDBu) for binding to phorbol-responsive PKC isoforms, the isolated C1b domain of PKC-delta (delta C1b), and the nonkinase phorbol ester receptor, beta2-chimaerin. In NIH/3T3 cells, AD 198 competitively blocks PKC activation by C1-ligands. Importantly, neither DOX nor N-benzyladriamycin, the principal AD 198 metabolite, inhibits basal or phorbol-stimulated PKC activity or appreciably competes for [3H]PDBu binding. In CEM cells, structure activity studies with 14-acyl congeners indicate that the rapid induction of apoptosis correlates with competition for [3H]PDBu binding, strongly implicating phorbol-binding proteins in drug activity. Collectively, these studies support the conclusion that AD 198 is a C1-ligand and that C1-ligand receptors are selective drug targets. These studies provide the impetus for continuing efforts to understand the molecular basis for the unique biological activity of AD 198 and provide for the design of analogues with improved affinity for C1-domains and potentially greater antitumor activity.     

Syphilis in pregnancy in Tanzania. I. Impact of maternal syphilis on outcome of pregnancy

To measure the impact of maternal syphilis on pregnancy outcome in the Mwanza Region of Tanzania, 380 previously unscreened pregnant women were recruited into a retrospective cohort at delivery and tested for syphilis. Stillbirth was observed in 18 (25%) of 73 women with high-titer active syphilis (i.e., women with a rapid plasma reagin titer > or = 1 :8 and a positive Treponema pallidum hemagglutination assay or indirect fluorescent treponemal antibody test result), compared with 3 (1%) of 233 uninfected women (risk ratio [RR], 18.1; P<.001). Women with high-titer active syphilis were also at the greatest risk of having low-birth-weight or preterm live births (RR, 3.0 and 6.1, respectively), compared with women with other serological stages of syphilis. Among unscreened women, 51% of stillbirths, 24% of preterm live births, and 17% of all adverse pregnancy outcomes were attributable to maternal syphilis. Syphilis continues to be a major cause of pregnancy loss and adverse pregnancy outcome among women who do not receive antenatal syphilis screening and treatment.     

Syphilis in pregnancy in Tanzania. II. The effectiveness of antenatal syphilis screening and single-dose benzathine penicillin treatment for the prevention of adverse pregnancy outcomes

Treatment for maternal syphilis with single-dose benzathine penicillin (2.4 million units intramuscularly) is being implemented in many parts of sub-Saharan Africa. To examine the effectiveness of this regimen, a prospective cohort of 1688 pregnant women was recruited in Tanzania. Birth outcomes were compared among women treated for high-titer (n=133; rapid plasma reagin [RPR] titer > or = 1:8 and Treponema pallidum hemagglutination assay [TPHA]/fluorescent treponemal antibody [FTA] positive) and low-titer (n=249; RPR titer <1:8 and TPHA/FTA positive) active syphilis and 950 uninfected women. Stillbirth or low-birth-weight live births were observed in 2.3% and 6.3%, respectively, of women treated for high-titer active syphilis and in 2.5% and 9.2%, respectively, of seronegative women. There was no increased risk for adverse pregnancy outcome for women treated for high-titer active syphilis (odds ratio [OR], 0.76; 95% confidence interval [CI], 0.4-1.4) or low-titer active syphilis (OR, 0.95; 95% CI, 0.6-1.5), compared with seronegative women. Single-dose treatment is effective in preventing adverse pregnancy outcomes attributable to maternal syphilis.     

Use of neoadjuvant and adjuvant therapy to prevent or delay recurrence of prostate cancer in patients undergoing surgical treatment for prostate cancer

There have been improvements in the outcome of patients with clinically localized prostate cancer treated by radical prostatectomy. However, some patients treated with radical prostatectomy will have clinical or biochemical progression. These men are at increased risk of dying of their disease. Identification of patients with adverse features at the time of radical prostatectomy may permit the use of additional multimodality therapies to improve outcomes. Whether this additional multimodality therapy should be administered in the neoadjuvant or adjuvant setting remains controversial. Further, whether a patient at increased risk for progression after radical prostatectomy requires additional therapy before the development of documented progression remains controversial. This article reviews the potential multimodality approaches to prevent or delay recurrence of prostate cancer in patients undergoing surgical treatment for prostate cancer.     

Mucin core peptide expression can help differentiate Barrett's esophagus from intestinal metaplasia of the stomach

It is important to distinguish Barrett's esophagus (BE) from intestinal metaplasia related to carditis because these conditions have a different natural history, risk of malignancy, and treatment. However, the distinction between these entities is difficult both clinically and pathologically. The aim of this study was to evaluate and compare the immunostaining pattern of five mucin core polypeptides in BE to cases of carditis or antritis with intestinal metaplasia. Routinely processed mucosal biopsies from 22 patients with intestinal-type BE, 24 patients with cardia intestinal metaplasia (10 Helicobacter pylori positive), 17 patients with antral intestinal metaplasia (all H. pylori positive), 20 control patients with a normal antrum, and 22 control patients with a normal cardia were immunostained with monoclonal antibodies against MUC1, MUC2, MUC3, MUC5AC, and MUC6 mucin core polypeptides. Staining was evaluated separately for goblet cells and non-goblet columnar cells and compared between all groups. A significantly higher number of BE cases (P < 0.05) showed goblet cell staining for MUC1 (55%) or MUC6 (32%) compared with patients with carditis with intestinal metaplasia (MUC1 14%, MUC6 7%) or antritis with intestinal metaplasia (MUC1 6%, MUC6 0%). BE also showed a higher frequency of MUC1 and MUC6 positivity in non-goblet columnar cells compared with carditis and antritis cases with intestinal metaplasia. Only cases of BE showed combined MUC1 and MUC6 staining (sensitivity 23%, specificity 100%). The sensitivity and specificity of MUC1 staining for BE are 55% and 96%, respectively, and for MUC6 staining 30% and 96%, respectively. Interestingly, normal gastric cardia mucosa also showed a significantly higher prevalence of MUC2 and MUC3 expression in glandular epithelium (29% and 38%, respectively) compared with the antrum (0% for both markers) (P < 0.05). In conclusion, MUC1 and MUC6 expression in BE is distinct from that of the cardia and antrum with intestinal metaplasia; thus, immunophenotyping for these markers may have some value in a subset of patients in helping to separate BE from patients with intestinal metaplasia of the cardia. Columnar epithelium in the "normal" gastric cardia has a partially intestinalized phenotype and, as a result, may represent an early form of metaplastic epithelium.     

Pathologic features of reflux and Helicobacter pylori-associated carditis: a comparative study

Inflammation of the gastric cardia, which is the most proximal portion of the stomach, in most instances is the result of either gastroesophageal reflux disease or H. pylori infection. Histologic distinction between these two entities is important because the treatment, natural history, and risk of malignancy are different. Moreover, multilayered epithelium, a possible precursor to Barrett's esophagus, has only recently been described in the gastric cardia, and its relationship to gastroesophageal reflux disease is unknown. The aim of this study was to compare the histologic features of the gastric cardia and the prevalence of multilayered epithelium in patients with reflux versus H. pylori-associated carditis. Routinely processed hematoxylin and eosin-stained mucosal biopsies of the gastric cardia from 30 patients with reflux-associated carditis, 25 with H. pylori-associated carditis, and 30 control patients (no reflux, no H. pylori) were evaluated for a wide variety of histologic features such as goblet cell metaplasia, presence of multilayered epithelium, type of glandular epithelium (mucous, oxyntic, mixed mucous/oxyntic), pancreatic metaplasia, overall degree of inflammation, and the quantity of individual types of inflammatory cells. The clinical and histologic features were compared between the two study groups and controls. Clinically, the reflux carditis group (male/female ratio: 21/9, mean age 56 years) had a significantly higher male/female ratio (p <0.01) and a slightly higher mean age in comparison with the H. pylori group (male/female ratio: 9/16, mean age 50 years). Histologically, the reflux group had significantly less overall inflammation (p <0.05), with fewer plasma cells (p <0.04) and neutrophils (p <0.006), but a higher prevalence of multilayered epithelium [9 of 30 (30%) vs 1 of 25 (4%) in the H. pylori group, p = 0.01]. In the reflux carditis group, multilayered epithelium was significantly associated with neutrophilic inflammation (p <0.05), but not any other features of chronic carditis or with any of the specific epithelial cell types. The control group showed less inflammatory activity in comparison with the H. pylori group and a lower prevalence of multilayered epithelium and eosinophilic inflammation in comparison with the reflux group. The clinical and pathologic features of reflux carditis are distinct from H. pylori carditis and are characterized by less overall inflammation and fewer neutrophils and plasma cells. Multilayered epithelium not uncommonly occurs in the cardia of patients with gastroesophageal reflux disease but without Barrett's esophagus, further supporting our hypothesis that multilayered epithelium may represent an early precursor in the development of columnar metaplasia in Barrett's esophagus.