A single dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin produces a time- and dose-dependent alteration in the murine bone marrow B-lymphocyte maturation profile.

The halogenated aromatic hydrocarbon, 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), is a ubiquitous, highly toxic environmental contaminant shown to produce immunotoxic effects in mammals. Although its immunotoxicity has been widely reported, little is known regarding its effect upon the development of immune-system cells, especially the B lymphocyte. The present study's purpose was to assess the effect that a single-dose administration of TCDD has, over time, upon bone marrow B-cell progenitors and pro/pre-B-, immature B-, and mature B-cell subpopulations, and to establish a dose-response relationship for these changes. Results showed that the mature B-lymphocyte subpopulation varied in a time-dependent manner, with a significant increase one day following TCDD treatment (30 microg/kg body weight [bw]), followed by a significant decrease at day 9 and a return to near-vehicle levels by day 31. Developing and less mature subpopulations were significantly decreased at days 6 and 9. The earliest B cell-progenitor subpopulation increased until day 9 and then decreased to vehicle-treated levels. Dose response (30, 15, 9, 6, 3, and 0.3 microg TCDD/kg bw) results at 2 days following treatment showed that only the mature-B subpopulation was affected at these doses, and below 6 microg/kg bw no effect was observed. These data suggest that the primary effect of TCDD is on those cells entering, and/or within, the mature B-lymphocyte subpopulation, and the alteration observed in the earlier maturation stages is a compensatory response to the effect on these mature cells.

Role of estrogen receptor alpha in hematopoietic stem cell development and B lymphocyte maturation in the male mouse.

Although estrogens and estrogen receptors (ERs) are known to function in the male brain and reproductive tract, few studies have evaluated their involvement in the male hematopoietic and immune systems. This study was undertaken to determine the role of ERalpha in hematopoietic progenitor and B lymphocyte maturation. ERalpha knockout (ER-/-), wild-type (ER+/+), and radiation chimeric (ERalpha positive or negative in either nonhematopoietic or hematopoietic elements, or both) male mice were used to determine target tissues. ER-/- and ER+/+ animals showed similar hematopoietic progenitor profiles, but the ER-/- animals had fewer cells in all bone marrow B lymphocyte subpopulations. Animals receiving a pharmacological dose (5 mg/kg BW) of 17beta-estradiol (E2) with both elements, ER+/+, had decreased early hematopoietic progenitors and a shift toward a mature B cell subpopulation, whereas animals with both elements, ER-/-, showed changes only in early hematopoietic progenitors. Hematopoietic element ER+/+ animals exhibited greater E2-induced hematopoietic progenitor and B lymphocyte alterations than those having only nonhematopoietic ERalpha. These data indicate that 1) ERalpha is not necessary for regulating male mouse normal hematopoietic progenitor cell proportions, but is involved in B cell regulation; and 2) ERalpha in hematopoietic elements is predominantly responsible for mediating E2-induced hematopoietic and B cell changes.

The aryl hydrocarbon receptor has a role in the in vivo maturation of murine bone marrow B lymphocytes and their response to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

The ligand-activated aryl hydrocarbon receptor (AHR) is a cytosolic DNA binding protein. Although no biologic role for AHR has been elucidated, it mediates the immunotoxicity of xenobiotics such as 2, 3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and its targeted inactivation produces abnormal immune system development. While investigators have demonstrated AHR's involvement in TCDD-induced B lymphocyte functional alterations, little is known about the receptor's possible role in early B cell maturation and whether exogenous ligands change this process. The purpose of this study was to determine, (1) whether bone marrow B lymphocyte maturation is affected by AHR presence, (2) if so, its relative importance in hematopoietic and/or nonhematopoietic elements and, (3) whether TCDD alters this process. Radiation chimeras were produced that were AHR positive (Ahr+/+) or negative (Ahr-/-) in either their nonhematopoietic or hematopoietic elements, or both. Marrow cells were analyzed for alterations in B lymphocyte maturation stage cell numbers in both vehicle- and TCDD-treated animals. Our results showed that (1) Ahr-/- animals had significantly higher numbers of pro/pre-B cells than Ahr+/+ animals, (2) TCDD treatment of Ahr+/+ animals produced a decrease in pro/pre-B cell numbers, whereas no effect was observed on Ahr-/- animals, and (3) AHR is required in both hematopoietic and stromal elements for maintenance of B cell subset maturation profiles.

A chimeric aryl hydrocarbon receptor knockout mouse model indicates that aryl hydrocarbon receptor activation in hematopoietic cells contributes to the hepatic lesions induced by 2,3,7, 8-tetrachlorodibenzo-p-dioxin.

Pathologic changes associated with 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) exposure have been reported in the livers of a wide range of species. While these changes have been extensively described, the mechanisms of toxic interaction(s) that produce these lesions remain unclear. Using an aryl hydrocarbon receptor (Ahr) knockout male mouse chimeric model, we investigated whether the presence of this receptor in hematopoietic and/or parenchymal cells affects TCDD-induced hepatotoxicity. Bone marrow chimeras were produced by hematopoietic reconstitution of irradiated mice. Specifically, chimeras were generated with aryl hydrocarbon receptor (AHR) positive hematopoietic and parenchymal cells (Ahr+/+ animal bone marrow cells into irradiated Ahr+/+ animals), AHR positive hematopoietic and negative parenchymal cells (Ahr+/+ into Ahr-/-), AHR negative hematopoietic and positive parenchymal cells (Ahr-/- into Ahr+/+), and AHR negative hematopoietic and parenchymal cells (Ahr-/- into Ahr-/-). Male wild-type (Ahr+/+) and knockout (Ahr-/-) animals were used as nonchimeric controls. Following TCDD treatment (30 microg/kg body wt), liver sections from mice in each control and chimeric group were histologically evaluated for necrotic and inflammatory changes. TCDD treatment produced moderate inflammation in Ahr+/+ controls and Ahr+/+ into Ahr+/+ chimeras. This response was mild in TCDD-treated Ahr-/-, Ahr-/- into Ahr-/-, Ahr+/+ into Ahr-/-, and Ahr-/- into Ahr+/+ animals and was not different from the corresponding vehicle-treated groups. Moderate necrosis was observed in all TCDD-treated controls or chimeras with AHR-positive parenchyma. No or mild necrosis was observed in TCDD- and vehicle-treated animals containing AHR-negative parenchyma. These data indicate that the presence of AHR in hepatic parenchyma alone is sufficient for TCDD induction of hepatic necrosis, and its presence in hematopoietic cells is necessary for the inflammatory response to TCDD-induced hepatic lesions.

Immunohistochemical detection of a fatty acid synthase (OA-519) as a predictor of progression of prostate cancer.

Prostate cancer is the most common newly diagnosed non-skin cancer and the second leading cause of cancer death in men. It is a unique neoplasm because of the large discrepancy between its clinical incidence and the much higher incidence of latent cancer. Predicting the prognosis of prostate cancer, especially the cancers detected incidentally or by screening, remains a clinically important problem. Immunoreactivity for Onco-antigen 519 (OA-519), a recently described fatty acid synthase (FAS), has been associated with poor prognosis in breast cancers. The authors have previously shown that its detection in prostate cancer correlated with high-grade, large volume, and advanced stage tumors. This study examines the association between OA-519 immunoreactivity in primary prostate cancer and disease progression. The authors used immunohistochemistry with an affinity-purified anti-OA-519 antibody and examined primary prostate cancers (stages A1 to D1) from 99 men with a mean follow-up of 4 years (range = 2 to 9.3). Survival analysis was used to evaluate differences in progression-free survival. OA-519 immunoreactivity was seen in 56 (57%) of the 99 primary prostate cancers examined. OA-519-positive cancers were more likely to progress than the OA-519-negative cancers (P < .04). Univariate survival analysis showed that OA-519 (FAS), histological grade (Gleason score), and clinical stage were significant predictors of disease progression. Multivariate analyses of all cases showed that only histological grade was significant. However, multivariate analysis of the 85 cancers with Gleason scores 2-7 (ie, low to intermediate grade) showed OA-519 (FAS) immunoreactivity to be the only statistically significant predictor of cancer progression (P < .02). Expression of the fatty acid synthase OA-519 by prostate cancers is potentially a clinically useful predictor of disease progression. It appears to be independent of histological grade (Gleason score), at least in cancers with low to intermediate grades. Further studies are needed to evaluate the role of fatty acid synthase in malignancy and the potential therapeutic implications of enzyme blockers.

The effect of indomethacin administration on the splenic changes induced by estradiol supplementation in ovariectomized New Zealand white rabbits.

In an effort to elucidate the mechanism by which indomethacin (IN) lessens the stimulatory effect of estradiol (E2) on rabbit splenic red pulp macrophages (RPMs), 39 female New Zealand White rabbits were divided into 10 groups: ovariectomized (OVX) and OVX/IN at 0.1 and 5.0 mg/kg body weight (bw)/day; sham OVX (SOVX) and SOVX/IN at 0.1 and 5.0 mg/kg bw/day; OVX/25 mg E2 and OVX/25 mg E2/IN at 0.1 and 5.0 mg/kg bw/day; and intact control. Changes in RPM population in response to treatment were measured using a 0-4 histologic grade. Estradiol treatment resulted in increased RPM grade when compared to the OVX groups. Indomethacin addition lowered mean RPM grade in the SOVX/IN 5.0 group when compared to its E2 control group. Indomethacin administration had no significant effect on levels of prostaglandin E2 in spleen, urine, or blood. Hematocrits were reduced in both OVX and OVX/E2 groups; this decrease was exacerbated by the high IN dose. In summary, the results from this study suggest that the effect of IN on E2-induced RPM activation may be mediated through a nonprostaglandin pathway. The observed hematocrit changes are possibly the result of direct action of IN and E2 on erythrocytes, resulting in their accelerated clearance from the circulation by splenic RPM.

In vitro effects of oestradiol and indomethacin on rabbit erythrocyte fragility characteristics.

An in vitro study was conducted to determine whether indomethacin (IN) and oestradiol (E(2)) induced decreases in rabbit haematocrit may be related to their effect on erythrocyte fragility (EF). Aliquots of treated rabbit whole blood were assayed as control, IN (9.6 mug/ml), E(2) (500 pg/ml) and IN + E(2), for changes in EF. Osmotic (OF) and mechanical (MF) fragility in eight experimental replicates were evaluated under approximate physiological conditions by measurement of haemoglobin release. Samples were assayed immediately after drug addition and again 4 hr after incubation at 39.5 degrees C. OF results showed a significant increase in 50% haemolysis between final IN and IN + E(2) values when compared with their initial values and with controls. OF haemolysis dispersion was increased over time by IN and IN + E(2). MF increased with IN, E(2) and IN + E(2) versus their initial values and the controls. Although the increase in MF from IN was greater than that from E(2), the MF from IN + E(2) was not greater than that from IN alone. The IN induced increases in both OF and MF indicate a difference in degree of interaction with the erythrocyte from that of E(2), which affected only MF and the effect of which was neither additive nor synergistic with that of IN.

Mathematical modeling of the osmotic fragility of rabbit red blood cells.

The osmotic fragility (OF) test is used to determine the extent of red blood cell hemolysis (RBCH) produced by osmotic stress. RBCH is dependent upon cell volume, surface area, and functional integrity of cell membranes. The variation of cell lysis with stress reflects underlying cell subpopulations and their membranes' cytoskeletal functionality. OF was determined on blood from New Zealand white rabbits. The dependence of RBCH on NaCl concentration ([NaCl]) was determined spectrophotometrically by measuring absorbance (Abs) from hemoglobin release at 545 nm. Abs data were fitted to the equation Abs = p3 erfc(([NaCl]--p1)/p2) where p3 reflects maximum RBCH, p1 measures the [NaCl] at 50% RBCH, and p2 shows the dispersion in [NaCl] producing the RBCH. Parameter values for control blood were p1 = 0.4489 +/- 0.0016; p2 = 0.0486 +/- 0.0016; and p3 = 0.4366 +/- 0.0022. Addition of indomethacin (9.6 micrograms/mL) produced an increased fragility in the RBC's characterized by increased values of p1 and p2. Normalization of the data to p3 did not change the values of p1 or p2. Our equation satisfactorily describes the variation in RBCH as a function of [NaCl]. The parameters of the equation can be used to quantitatively characterize Abs/[NaCl] data and compare pharmacological, toxicological, and pathological effects on the OF of RBC's.

Immunohistochemical detection of p53 protein as a prognostic indicator in prostate cancer.

Mutation of the p53 gene is the most common genetic alteration in human cancers. The mutant p53 protein is more stable than the wild type and can be detected by immunohistology. The objective of the current study was to evaluate the immunohistological detection of p53 protein in prostate cancer and its utility as a prognostic indicator. We used a monoclonal anti-p53 antibody and immunostained primary prostate adenocarcinomas (stages A1 to D1) from 109 patients with a mean follow-up of 3.8 years (range, 1.3 to 9.3 years). Immunoreactivity for p53 was seen in 23 cancers (21%). There were 12 instances of progression (14%) among the p53-negative cancers versus seven (30%) among the p53-positive group. Survival analysis using three univariate statistical tests showed that p53 reactivity (P < .03), Gleason score (P < .01), and stage (P < .05) had significant effects on time to progression of prostate cancer. Multivariate analyses showed that Gleason score was significant with all three tests; p53 reactivity was significant with the Wilcoxon test but only approached significance by the log rank and Cox tests. When the analyses included only patients with Gleason scores 2 to 7 (N = 94), univariate analyses showed that p53 reactivity was strongly related to progression of prostate cancer (P < .007). Stage also was significant (P < 0.04), but Gleason score was not. Multivariate analyses showed only p53 reactivity to be significant (P < .007). In conclusion, mutation of the p53 gene may be involved in prostate cancer carcinogenesis. p53 reactivity marks an aggressive subset of prostate cancer and appears to be an independent prognostic indicator that is particularly valuable among the low to intermediate grade cancers.

Proliferating cell nuclear antigen immunoreactivity in cervical intraepithelial neoplasia and benign cervical epithelium.

In the normal ectocervix, mitoses are rare and are usually confined to the basal layers. In contrast, they occur more frequently in cervical intraepithelial neoplasia (CIN) and are seen at higher levels, suggesting that CIN may be associated with a progressive dysfunction in proliferative activity of cervical cells. The objective of this study was to use proliferating cell nuclear antigen (PCNA) immunohistochemistry to examine the proliferative activity of cervical epithelial cells in CIN lesions. Sixty-eight cervical biopsies were examined; 20 were totally benign, 14 had CIN I, 21 CIN II, and 13 CIN III. In benign epithelia, PCNA staining was usually confined to the basal layers, whereas in CIN the staining was seen at progressively higher levels of the epithelium. There was a statistically significant correlation between the CIN grade and the highest level of PCNA staining (PCNA grade, r = 0.746, P < 0.001). In addition, the PCNA grade showed significant correlation with the highest level at which mitoses were seen (mitosis grade, r = 0.706, P < 0.001), and a strong direct correlation between the mitosis and CIN grades was also observed (r = 0.955, P < 0.001). These data demonstrate that (1) PCNA immunoreactivity in neoplastic cervical epithelium is different from that seen in the normal cervix, suggesting that CIN is associated with a dysfunctional proliferation of cervical epithelium, (2) that there is a significant correlation between the PCNA grade and CIN grades, and (3) the "mitosis grades" have a strong correlation with the CIN grades.

Expression of oncogenic antigen 519 (OA-519) in prostate cancer is a potential prognostic indicator.

Predicting the prognosis of patients with prostate cancer is a clinically important problem. Previous studies have indicated that the expression of haptoglobin-related protein epitopes in samples of breast cancer in early stages was associated with earlier relapses and higher risk for tumor recurrence. Oncogenic antigen 519 (OA-519) is the new marker designation for molecules expressing haptoglobin-related protein epitopes. The objective of this immunohistochemical study was to examine OA-519 expression in prostate cancer samples and its relationship to the established prognostic indicators of tumor grade, tumor volume, and clinical stage. Forty-two consecutive tissue samples of prostate adenocarcinoma were examined using an affinity-purified anti-OA-519 antibody. Twenty specimens (48%) tested positive, whereas 22 (52%) tested negative. No staining was observed in normal or hyperplastic prostate tissue. Staining occurred in 6 of 9 (67%) grade III, 14 of 23 (61%) grade II, and in none of 10 (0%) grade I cases (I vs. II and/or III: Fisher exact test, P less than 0.006). Twenty-three of the 42 samples were transurethral resection specimens with cancer; 11 (48%) of these tested positive. The mean percentage of tissue chips with tumor, a measure of tumor volume, was significantly higher in the positive group (57%) than in the negative group (15%) (P = 0.004). The proportion of positively stained cases increased with advancing clinical stage, with 25% of Stage A cases expressing OA-519, and 46%, 67%, and 64% of Stages B, C, and D, respectively, expressing OA-519. OA-519 expression correlates with higher tumor grades, larger tumors, and possibly with advanced stage, and thus, it is potentially of prognostic value in prostate cancer.