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Biomedical subjects

G P Haas

Publications and source records attributed to G P Haas.

At least 19 recordsLinked to original sources
PubMed2000

Carcinogenicity of the N-hydroxy derivative of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-3, 8-dimethyl-imidazo[4,5-f]quinoxaline and 3, 2'-dimethyl-4-aminobiphenyl in the rat.

Heterocyclic amines and carcinogenic aromatic amines are similarly metabolically activated suggesting that they may have similar organ specificity. Three day-old male ACI/seg rats were injected, i.p., twice a week for 10 weeks with 50 micromol/kg of N-hydroxy-3, 2'-dimethyl-4-aminobiphenyl (N-OH-DMABP; Group II), N-OH-2-amino-3, 8-dimethylimidazo[4,5-f]quinoxaline (N-OH-MeIQx; Group III) or N-OH-2-amino-1-methyl-6-phenylimidaza-[4,5-b]pyridine (N-OH-PhIP; Group IV). Animals in control group (Group I) were similarly injected with solvent alone. The animals were sacrificed at age 68 weeks, and 31, 30, 27 and 31 rats from Groups I, II, III and IV, respectively, were evaluated. Colon carcinomas were found in 0, 15 (P<0.001), 2 and 4 (P<0.06), and bladder transitional cell tumors in zero, two, two and four (P<0.06), in Group I, II, III and IV, respectively. The incidence of atypical hyperplasia of ventral prostate in Groups III and IV, and of anterior prostate and seminal vesicle in all treated groups was also significantly greater (P<0.05). These results suggest that N-OH-PhIP and N-OH-MeIQx may be potential carcinogens for the prostate. Since bladder tumor is rare in ACI rats, N-OH-PhIP may also be a potential carcinogen for the bladder.

Aminobiphenyl Compounds↗
PubMed2000

Inhibition of lung metastases of murine renal cell carcinoma by the combination of radiation and interferon-alpha-producing tumor cell vaccine.

We have previously demonstrated in a murine lung metastasis model that local sublethal radiation of tumors can synergistically enhance their sensitivity to immunotherapy with either systemic high-dose interleukin-2 (IL-2) or vaccination with autologous tumor cells expressing IL-2, interferon (IFN)-gamma and granulocyte-macrophage colony-stimulating factor (GM-CSF). Host antitumor activity was mediated in large part by natural killer cells, which can be activated by IFN-alpha. In the present study, we used this lung metastasis model to investigate the efficacy of combined therapy with local tumor radiation and vaccination with IFN-alpha-secreting tumor cells (Renca/IFN-alpha). The in vitro and in vivo growth rates of Renca/IFN-alpha cells were significantly reduced relative to normal controls. Subcutaneous vaccination with Renca/IFN-alpha or selective X-irradiation of the left lung (300 rad) reduced the number of lung tumors by 40% and 27%, respectively. The combination of lung irradiation plus vaccination reduced the number of lung metastases by 60%, and the net tumor volume by 95%. The reductions in tumor volume in both irradiated and non-irradiated lungs were comparable. These results indicate that host antitumor response to subcutaneous vaccination with Renca/IFN-alpha was systemic, and was significantly enhanced by radiation of tumor-bearing lungs. A regimen based on enhancement of IFN-alpha immunotherapy by local tumor radiation may be useful in the treatment of metastatic renal cell carcinoma.

Animals↗
PubMed2000

Epidemiology and molecular biology of early prostatic neoplasia.

This paper provides our institutional data with respect to the prevalence of early neoplastic changes within the prostate gland and the age and race distribution of the patients. The changes examined were prostatic intraepithelial neoplasia (PIN) and preclinical (latent) cancers. The literature on the prevalence of these early lesions among different geographic and ethnic groups is summarized, and an abbreviated review of the more common molecular alterations reported at this early phase of prostatic neoplasia is offered.

Adenocarcinoma↗
PubMed1999

Prostatic intraepithelial neoplasia and apoptosis in benign prostatic hyperplasia before and after the Chernobyl accident in Ukraine.

The prevalence of prostatic intraepithelial neoplasia (PIN) in men who underwent surgery for benign prostatic hyperplasia (BPH) before and after the Chernobyl nuclear accident was studied. BPH samples were obtained by adenomectomy from 45 patients operated in 1984 before the accident (Group I), and 47 patients from the low contaminated Kiev City (Group II) and 76 from high contaminated area (Group III) operated between 1996 and 1998. Their BPH samples were examined histologically and immunohistochemically. The incidences of prostatic intraepithelial neoplasia (PIN) and high grade PIN (HGPIN) were 15.5 and 11.1% in Group I, 29.8 and 14.9% in Grpoup II, and 35. 5 and 19.7% in Group III. The difference between the incidences of PIN in Group I and III is significant (p<0.02). There was increased apoptosis in areas of PIN in Group II and III as compared to Group I (p<0.001). Since apoptosis has been shown to be associated with ionizing radiation and it is now found to be associated with PIN in patients diagnosed after the Chernobyl nuclear accident, this suggests that long-term low dose internal ionizing radiation potentially may cause prostate cancer.

Apoptosis↗
PubMed1999

N-Acetyltransferase expression and DNA binding of N-hydroxyheterocyclic amines in human prostate epithelium.

Intact prostate epithelial cells prepared from benign prostatic hypertrophy tissues from two patients were incubated for 2 h with N-hydroxy derivatives of 2-amino-1-methyl-6-phenylimidazo[4, 5-b]pyridine (N-OH-PhIP) or 2-amino-3,8-dimethylimidazo[4, 5-f]quinoxaline (N-OH-MeIQx). (32)P-post-labeling analysis detected PhIP and MeIQx adducts in the DNA of these cells but not in the untreated control. Adduct levels were approximately 100 times greater in N-OH-PhIP- than in N-OH-MeIQx-treated cells. Repair synthesis of DNA was observed in cells, prepared from two additional patients, treated for 24 h with these carcinogens and was greater for N-OH-PhIP than for N-OH-MeIQx. PhIP, MeIQx and their nitro derivatives did not produce repair synthesis of DNA in this system. The difference in the activity of N-OH-PhIP and N-OH-MeIQx may be due to their stability, since N-OH-MeIQx decomposed rapidly in neutral solution. Transcripts of NAT1 and NAT2 were detected by an in situ hybridization method in prostate epithelial cells, but were absent from stromal tissues. These results suggest that PhIP may be a potential carcinogen for human prostate, since cooked meats, which contain this heterocyclic amine, have been associated with human prostate cancer.

Arylamine N-Acetyltransferase↗
PubMed1999

Immunotherapy for lung metastases of murine renal cell carcinoma: synergy between radiation and cytokine-producing tumor vaccines.

We investigated the combination therapy of local radiation of lung metastasis and vaccination with autologous tumor cells that produced interleukin (IL)-2, interferon-gamma (IFN-gamma), and granulocyte-macrophage colony-stimulating factor (GM-CSF) using the mouse Renca pulmonary metastasis model. Wild-type Renca (W/Renca) were transfected with pEF-BOS vector incorporating cDNAs for IL-2, IFN-gamma, or GM-CSF to express these cytokines. W/Renca, IL-2-producing Renca (Renca/IL-2), and IFN-gamma-producing Renca (Renca/IFN-gamma) produced subcutaneous tumor at the injection site in eight of eight, one of eight, and two of eight mice, respectively. No tumors were found in the GM-CSF-producing Renca (Renca/GM-CSF) group (zero of eight). Renca/IFN-gamma produced subcutaneous (s.c.) tumors in all Balb/c nude mice, but Renca/IL-2 and Renca/GM-CSF did not. To test the elicitation of antitumor activity, Balb/c mice were injected intravenously with 1 x 10(5) W/Renca on day 0, vaccinated, s.c., with 1 x 10(6) cells each of 5,000 rad preirradiated Renca/IL-2, Renca/IFN-gamma, and Renca/GM-CSF or 3 x 10(6) cells of preirradiated W/Renca on days 1, 7, and 14, and radiated with 300 rad to both lungs on day 5. The animals were killed on day 21 and tumor nodules in the lungs were enumerated. Neither local irradiation alone nor the combination of lung radiation and multiple vaccination with irradiated W/Renca significantly reduced the number of lung tumors. In contrast, the combination of lung radiation and the multiple vaccinations with cytokine-producing Renca cells significantly reduced the number of lung tumors. This regimen was more effective than the multiple vaccinations with cytokine-producing Renca cells alone. These studies demonstrate the efficacy of vaccination with autologous tumor cells expressing these cytokines and sensitization of the tumor target with radiation.

Animals↗
PubMed1999

Cisplatin, methotrexate and bleomycin for the treatment of carcinoma of the penis: a Southwest Oncology Group study.

PURPOSE: We ascertained whether combined cisplatin, methotrexate and bleomycin have efficacy for treating locally advanced or metastatic carcinoma of the penis, and evaluate the toxicity resulting from this regimen. MATERIALS AND METHODS: Patients had biopsy proved locally advanced or metastatic epidermoid carcinoma of the penis. Chemotherapy consisted of 75 mg./m.2 cisplatin infused intravenously on day 1, 25 mg./m.2 intravenous bolus of methotrexate on days 1 and 8, and 10 unit per m.2 intravenous bolus of bleomycin on days 1 and 8 with a cycle length of 21 days. Our study was performed as a standard phase II evaluation with 2 stages of accrual. RESULTS: Enrolled in this study were 45 patients, including 40 who were evaluable for a response. There were 5 complete and 8 partial responses for a 32.5% response rate. Five treatment related deaths occurred and 6 of the 36 remaining patients evaluable for toxicity had 1 or more life threatening toxic episodes. CONCLUSIONS: A regimen of cisplatin, methotrexate and bleomycin appears to have promising results. However, toxicity was prodigious, and an emphasis of future research should be to decrease toxicity.

Adult↗
PubMed1998

Cirsoid arteriovenous malformation of kidney presenting as a mass suggestive of malignancy.

This paper reports a rare case of cirsoid renal arteriovenous malformation (AVM) that showed radiological characteristics of a renal malignancy. Using only conventional procedures such as computerized tomography, the present case was misdiagnosed as a solid tumor mass and therefore radical nephrectomy was indicated. Angiographic analysis is expected to improve the accuracy of diagnosis of AVM, thus reducing the need to resort to invasive techniques.

Arteriovenous Malformations↗
PubMed1998

Phase II trial of sequential radiation and interleukin 2 in the treatment of patients with metastatic renal cell carcinoma.

We have previously demonstrated that local tumor irradiation effectively enhanced the therapeutic effect of interleukin 2 (IL-2) therapy in an experimental murine renal adenocarcinoma model. Based on these preclinical studies, we have designed and initiated a Phase II trial of irradiation combined with IL-2 for the treatment of metastatic renal cell carcinoma. Patients received 800 cGy to the primary or metastatic lesions on days 1 and 15 followed by IL-2 (600,000 IU/kg i.v.) every 8 h on days 4-8 and 18-22. Sixteen patients were entered; all completed treatment and are therefore evaluable for toxicity and response. Two partial remissions were seen for a response rate of 12.5% (95% confidence interval, 0-28.7). There was no increase in toxicity over that which is anticipated from IL-2 alone. The antitumor activity seen in this trial is consistent with what would be expected from high-dose IL-2 alone.

Adult↗
PubMed1998

Pathology of premalignant lesions and carcinoma of the prostate in African-American men.

The objective of this study was to summarize data describing the morphological characteristics of the spectrum of prostatic neoplasia in African-American men and compare them to their equivalents in Caucasian men. Studies that have emphasized the documentation of pathological features of prostate cancer or its putative precursors in African Americans are reviewed and are contrasted with comparable data concerning Caucasians. The author's experience is also presented. There is significant overlap between the pathological features of prostate cancer in African Americans and Caucasians in their clinical associations. The main pathological parameter reported with consistency to differ between the two groups is the observation that African-American patients present with a more advanced stage of the disease compared with Caucasian patients. Reports on differences in the grade and volume of the disease are less consistent. Comparative data on "preclinical," autopsy-type cancers and those concerning premalignant lesions indicate a similar prevalence of autopsy cancers between the two races while the prevalence and extent of high-grade prostatic intraepithelial neoplasia is higher in African-American men compared with Caucasian men. The difference is more evident in younger individuals. In conclusion, there are indications that African-American men with clinically localized prostate cancer tend to have a more advanced pathological stage at the time of radical prostatectomy compared with Caucasian men. Our data also indicate a higher prevalence of a putative precursor for clinically evident prostate cancer, high-grade prostatic intraepithelial neoplasia in African-American men. The earlier onset and extensiveness of this lesion may contribute to the higher incidence of clinically evident prostate cancer in African Americans.

Adenocarcinoma↗
PubMed1997

Interleukin-13 receptors on human prostate carcinoma cell lines represent a novel target for a chimeric protein composed of IL-13 and a mutated form of Pseudomonas exotoxin.

We have discovered a new cell surface protein in the form of interleukin-13 receptor on several solid tumor cells, including human renal cell carcinoma cells (Obiri et al., 1995; Debinski et al., 1995). This study reports that human prostate cancer cell lines also express high affinity IL-13 receptors (Kd = 159 pM). These receptors are functional because IL-13 surprisingly increased proliferation of all three prostate cancer cell lines studied as determined by thymidine uptake and clonogenic assays. IL-13 receptors on prostate cancer cell lines were targeted using a chimeric protein composed of IL-13 and a mutated form of Pseudomonas exotoxin (PE38QQR). This molecule, termed IL13-PE38QQR, has been found cytotoxic to all three prostate cancer cell lines as determined by the inhibition of protein synthesis. The IC50 ranged between 1 nmol/l, to 15 nmol/l. These data were confirmed by clonogenic assays in which IL13-PE38QQR almost completely inhibited colony formation at 10 nmol/l. IL13-PE38QQR was not cytotoxic to cells that express little or no IL-13R. Heat inactivated IL13-PE38QQR was not cytotoxic to prostate cancer cells indicating specificity. IL13-PE38QQR was also cytotoxic to colonies when they were allowed to form first for several days before the addition of toxins. Our data suggest that additional studies should be performed to target IL-13 receptor bearing prostate cancer.

ADP Ribose Transferases↗
PubMed1997

Prostate specific antigen decreases after withdrawal of antiandrogen therapy with bicalutamide or flutamide in patients receiving combined androgen blockade.

PURPOSE: We determined whether decreases in prostate specific antigen (PSA) would occur after withdrawal of double-blinded antiandrogen therapy with flutamide or bicalutamide for clinical progression or increasing PSA concentration in patients receiving combined androgen blockade for advanced prostate cancer. MATERIALS AND METHODS: PSA concentrations were determined weekly for at least 6 weeks and then every other week for 6 weeks in 22 patients with stage D2 prostate cancer. All patients were withdrawn from antiandrogen therapy (8 flutamide and 14 bicalutamide) due to progression or an increasing PSA concentration. Objective response was evaluated before antiandrogen withdrawal and at week 12. RESULTS: In 4 of 8 patients (50%) withdrawn from flutamide and 4 of 14 (29%) withdrawn from bicalutamide serum PSA concentrations decreased by 50% or more. PSA responses after withdrawal of flutamide therapy occurred within the first few days, whereas those after withdrawal of bicalutamide therapy occurred within 4 to 8 weeks. Of 4 patients assessed for objective response 2 had stable disease and 2 had progression. A PSA response was observed in the 2 patients with stable disease but not the 2 with progression. CONCLUSIONS: For patients with stage D2 prostate cancer and disease progression or an increasing PSA concentration, withdrawal of antiandrogen therapy with bicalutamide or flutamide may result in a PSA response. The time to PSA response is longer with bicalutamide than with flutamide. The clinical significance of the antiandrogen withdrawal phenomenon is unknown.

Aged↗
PubMed1997

Clinicopathologic and interphase cytogenetic analysis of papillary (chromophilic) renal cell carcinoma.

Trisomy 7 and 17 with deletion of Y is typical of papillary renal cell adenoma (PRCA), and additional alterations occur in the putative genetic progression toward papillary renal cell carcinoma (PRCC). Our study correlated aneuploidy with clinicopathologic features in PRCCs. We used fluorescence in situ hybridization to assess copy number for chromosomes 7, 8, 10, 12, 16, 17, and Y in 16 PRCCs and surrounding benign tubular parenchyma from 15 patients by use of alpha satellite (centromere) probes on deparaffinized tissue sections. We then compared the pattern of monosomy/nullisomy or trisomy/polysomy/hemidisomy to clinicopathologic parameters. Nine tumors (58% Group 1) showed the numeric aberrations typical of PRCAs and PRCCs, with gains of 7 and 17 and loss of Y. We also identified four trisomies of 12 and 16 and one of 8 in Group 1. The remaining seven cases (Group 2) were cytogenetically atypical. Two displayed borderline loss of chromosome 7, although trisomy 17 was present in both. Five had trisomy 7, but none exhibited chromosome 17 alterations, and two exhibited a gain of Y. Neoplasms in Group 2 were less often multicentric than were Group 1 tumors, and they contained foamy macrophage infiltrates less often. One chromophilic carcinoma with abundant clear cells and another with oncocytic features exhibited Group 2 chromosomal profiles. One patient (nuclear grade 4) died from disease, and 14 had no evidence of carcinoma at the last follow-up. We concluded that PRCCs represent a histologically and genotypically heterogeneous group of tumors. If PRCAs consistently exhibit +7, +17, and -Y, it is uncertain whether PRCCs always evolve directly from such lesions. The presence of genotypic heterogeneity might reflect histologic variants of PRCCs, which overlap with other types of RCC. PRCC is generally an indolent neoplasm, despite a high frequency of chromosomal aneuploidy.

Adult↗
PubMed1997

Inhibition of murine renal carcinoma pulmonary metastases by systemic administration of interferon gamma: mechanism of action and potential for combination with interleukin 4.

We have previously demonstrated that IFN-gamma causes cell growth inhibition and up-regulation of MHC antigens in human renal cell carcinoma cell lines. In this study, we have investigated the therapeutic potential of IFN-gamma for the treatment of 5-day established pulmonary metastases induced by i.v. injection of Renca cells, a murine renal adenocarcinoma. We found that systemic injections of IFN-gamma significantly reduced the number of lung metastases in a dose-dependent manner and increased mouse survival. Histological evaluation of IFN-gamma-treated lungs showed residual small tumor nodules containing extensive necrosis and mononuclear infiltrates. Immunohistochemistry studies on lung sections showed macrophage infiltration into tumor nodules, and in vivo depletion of macrophages partially inhibited IFN-gamma antitumor effect, suggesting a role for the macrophages in tumor destruction. Lymphocyte depletion of either natural killer (NK) cells or CD4+ or CD8+ T-cell subsets or both T-cell subsets did not affect the IFN-gamma effect, whereas depletion of both NK and T cells decreased the antitumor activity of IFN-gamma. These data indicate that neither T cells nor NK cells are essential for this activity but that either lymphocyte population can contribute to the IFN-gamma effect. An optimal dose of IFN-gamma inhibited by 60% the growth of Renca cells treated for 3 days in vitro, but this effect was transient and less pronounced in a long-term colony assay, suggesting that IFN-gamma direct growth inhibition may play a role but may not be sufficient to mediate its antitumor effect in vivo. In vitro, IFN-gamma caused up-regulation of class I MHC antigens and induction of class II antigen expression in Renca cells, an effect that may enhance Renca immunogenicity but may be relevant only when a T-cell response is elicited. A sequential administration of IFN-gamma followed by interleukin 4 was therapeutically better than IFN-gamma alone for the treatment of advanced pulmonary metastases, probably due to different antitumor mechanisms induced by these two cytokines.

Animals↗
PubMed1996

Targeting of interleukin-13 receptor on human renal cell carcinoma cells by a recombinant chimeric protein composed of interleukin-13 and a truncated form of Pseudomonas exotoxin A (PE38QQR).

We have previously shown that human renal cell carcinoma (RCC) cells express large numbers of interleukin-13 receptors (IL-13R), a newly described hemopoietic growth factor receptor. To target tumor cells that express IL-13R, we have produced a chimeric protein composed of human IL-13 and a derivative of Pseudomonas exotoxin A, termed PE38QQR. We report here that IL13-PE38QQR is highly cytotoxic to many human RCC cell lines. IL-13R-negative cell lines or cell lines expressing low numbers of IL-13R ( < 300 sites/cell) that include human bone marrow-derived cells were not susceptible to the cytotoxic effect of IL 13-PE38QQR. The sensitivity of RCC cells to IL13-PE38QQR correlated positively with the density of IL-13R. The cytotoxic activity of IL13-PE38QQR was competed by an excess of IL-13 in a protein synthesis inhibition assay and confirmed by a clonogenic assay. Even though IL-13 and IL-4 are homologues and IL-4R and IL-13R have been proposed to share a receptor subunit, IL-4 did not compete for the cytotoxicity mediated by IL13-toxin on RCC. IL13-PE38QQR competes for [125I]-IL-13 binding sites on RCC cells, although at a lower affinity than the wild-type recombinant cytokine. Human T-cell, B-cell, and monocytic cell lines are unresponsive to the cytotoxic action of IL13-PE38QQR. Thus, our results indicate that IL13-PE38QQR is highly cytotoxic to human RCC cells, although it is not cytotoxic to a variety of normal hematopoietic cells. IL13-PE38QQR should be further investigated preclinically for the treatment of human RCCs.

ADP Ribose Transferases↗
PubMed1996

Age and racial distribution of prostatic intraepithelial neoplasia.

AIMS: To study the prevalence, extent and evolution of high-grade prostatic intraepithelial neoplasia (HGPIN) in African-American and Caucasian men of a wide age range in order to help clarify the role this lesion may play in the racial differences of prostate cancer. METHODS: The lesion was documented in step-sectioned, entirely submitted prostates of two study populations: 525 autopsied men who died of trauma and 1,000 patients who had retropubic radical prostatectomy for clinically localized carcinoma of the prostate. RESULTS: We found that HGPIN starts in young individuals and increases progressively with advancing age in both races but is more prevalent in African-Americans. Additionally, the more extensive form of HGPIN with multifocal or diffuse involvement of the gland appears at a younger age in African-Americans. CONCLUSIONS: Microscopic foci of HGPIN can be documented in males in the 3rd and 4th decades with the lesion becoming more extensive in older men. The finding that HGPIN is both more prevalent and its more diffuse form appears earlier in African-Americans, indicates a potentially important role for this lesion in the race-related discrepancies associated with this disease.

Adult↗