Acid spill impact on Sonora River basin. Part I. sediments: Affected area, pollutant geochemistry and health aspects.

The Sonora River and its tributary streams (Tinajas, Bacanuchi) were impacted in 2014 by an acid solution spill (approximately 40,000 m3). This study aims to presents a clear and supported overview to determining the spill's consequences on the environment and the people inhabiting the area. The elements quantified were those found in the spilled solution: Al, As, Cu, Fe, Mn, Pb, and Zn. Potential Toxic Element (PTE) concentration means from 187 sediment samples were, in mg.kg-1: Al = 7,307, As = 16.6, Ba = 128 Cu = 106 Fe = 15,764, Mn = 566, Pb = 46 and Zn = 99. Differences between PTE concentrations in the most impacted sediments and those of the local baseline, sampled in streams not affected by the spill and regional baseline values, were not statistically significant. The similarity of PTE concentrations among sediments may be explained by natural geological enrichment, historical mining impacts, and a low increase of PTE in sediments after the acid spill because of natural and anthropogenic attenuation. Mainly heavy rains, natural pedogenic carbonates, and remedial work done by the mining company (retaining dam, adding lime; precipitation, collecting formed solids, and transport to the mine). The Contamination Factor (C.F.), Enrichment Factor (E.F.), and Geo-accumulation Index (Igeo) were determined. The C.F. indicated low and moderate contamination in all elements. Cu exhibited the highest E.F., from moderate to significant enrichment. The Igeo generally ranged from -0.02 to 0.15. Cu and Zn were classified as moderately to heavily contaminated. In local baseline sediments, the Cu C.F. varied from moderate to very high contamination, the Cu E.F. from moderate to significant enrichment, while the As, and Pb Igeo ranged from uncontaminated to moderately contaminated. In general, normalization demonstrated a high degree of Cu enrichment at sites 1-14. Sequential extractions indicated that only Cu was found in all fractions, including a significant exchangeable fraction in the very impacted sediments (1-14). The other PTEs were distributed between the Fe/Mn oxide fraction and the residual phase. Principal Components Analysis for PTE concentrations indicated three different groups with similar geochemical patterns and allowing to identify the PTE potentially sources: the first sediments from sites 1-14 were the impacted sediments in accordance with pH and electrical conductivity results, the second group from sites 15-20 showed characteristics of the mineralized environment, and the third from sites 21-30 were unrelated to the spillage. The area impacted by the acid solution spill reached approximately 30 km downstream, just roughly 15% of the initially considered area.

Removal of microorganisms in different stages of wastewater treatment for Mexico City.

In this study the removal of a diversity of microorganisms during different stages of treatment was evaluated. The process scheme consisted of Advanced Primary Treatment (APT), sand filtration, and chlorine disinfection. During the first 2 stages, fecal coliforms were reduced from 1.24 x 10(9) to 1.2 x 10(8) MPN/100 mL and helminth ova were reduced to less than 1 ova/L. Nevertheless, to obtain an effluent water quality that meets the microbiological standards recommended by the World Health Organization (1989) and the Mexican norm for water destined for agricultural reuse it was necessary to disinfect the effluent with a chlorine dose of 12 mg/L for a 3 hour contact time. Under these conditions, fecal coliforms were reduced from 1.2 x 10(9) to 5.8 x 10(1) MPN/100 mL, Salmonella spp. from 5.0 x 10(8) MPN/100 mL to below the detection limit, Pseudomonas aeruginosa from 2.0 x 10(5) MPN/100 mL to below the detection limit, and protozoan cysts from 1052 to 31 cysts/L. Regrowth of bacteria was never observed during the 48 hours period following disinfection. The active chlorine was primarily in the form of chloramines thus reducing the formation of other potentially carcinogenic disinfection byproducts.

Identification of women with T1-T2 breast cancer at low risk of positive axillary nodes.

BACKGROUND AND OBJECTIVES: The diagnostic and therapeutic significance of axillary dissection has been questioned. We sought to define a subgroup of patients with early-stage breast cancer who are at low risk for positive axillary nodes. METHODS: Between 1970 and 1995, 1,598 women with stage I and II breast cancer underwent level I-II axillary dissection with a minimum of 10 nodes removed. The following factors were examined in univariate analysis for predicting positive nodes: race, method of detection, location of the primary tumor, age, menopausal status, obesity, ER status, PR status, pathologic tumor size, lymphatic vascular invasion, tumor grade, and histology. RESULTS: Four hundred and forty-five of the 1,598 patients (27.8%) had histologically positive axillary nodes. Significant factors in univariate analysis for positive nodes included: tumor size, lymphatic vascular invasion, grade, method of detection, primary tumor location, and age. The only group of women with a 0% risk of axillary nodes were those in whom the pathologic tumor size was < or = 5 mm and mammographically detected. A 5-10% risk of positive axillary nodes was identified in women with (1) pathologic tumor size 6-10 mm, mammographically detected, and age < or = 40 years, and (2) tubular carcinoma < or = 10 mm. Tumors detected on physical examination with or without mammography and women < or = 40 years had a significantly increased risk of nodes. In multivariate analysis lymphatic vascular invasion (P < 0.001), method of detection (P = 0.026), location (P = 0.01), and pathologic tumor size (P = 0.002) were significant predictors of positive axillary lymphadenopathy. CONCLUSIONS: The decision to forego an axillary dissection should be considered in (1) tumors mammographically detected and < or = 5 mm (2) mammographically detected, pathologic size 6-10 mm, age > 40 and (3) tubular carcinoma < or = 10 mm. All other groups had a > 10% risk of nodes and may benefit from axillary dissection.

Activation of Raf-1 in human pancreatic adenocarcinoma.

Point mutations in the Ras oncogene cause Ras to remain in its active GTP-bound state sending signals downstream continuously. Since 75 to 90% of all human pancreatic ductal adenocarcinomas harbor activating mutations at codon 12 of the K-ras oncogene it was our belief that Raf-1-MEK-MAPK will be activated in the majority of human pancreatic cancers. The aim of this study was to confirm activation of Raf-1 in K-ras mutant human pancreatic cancer. Additionally, we sought to determine if Raf-1 activation differed in K-ras mutant and nonmutant pancreatic cancer. Furthermore, we were interested in determining if Raf-1 activation in pancreatic cancer led to subsequent activation of downstream effectors such as MAP kinase. The presence of mutations in codon 12 of the K-ras oncogene in 14 human pancreatic adenocarcinoma cell lines was determined by use of mutant allele-specific PCR restriction fragment length polymorphism analysis. Raf-1 expression of quiescent cells was determined by immunoblotting using a rabbit anti-human polyclonal antibody and enhanced chemiluminescence. MAP kinase activity was determined by measuring the incorporation of phosphate into Myelin Basic Protein. Seven cell lines were noted to have mutations in codon 12 of K-ras while seven cell lines did not. There was no difference in expression of the 74 kDa-activated form of Raf-1 in K-ras mutant vs K-ras nonmutant cell lines. However, there was a significant increase in MAP kinase activity in the nonmutant cell lines compared to the cell lines with Ras mutations (P = 0.026). We conclude that Raf-1 is expressed in its active form in human pancreatic cancer regardless of K-ras status. However, signalling downstream of Raf-1 differs in cell lines with K-ras mutations compared to those cell lines without K-ras mutations.

Factors associated with a positive reexcision after excisional biopsy for invasive breast cancer.

BACKGROUND: Breast-conserving therapy followed by adjuvant radiotherapy represents an alternative to mastectomy as a treatment for invasive breast cancer. When excisional biopsy has been performed outside the parent institution, reexcision is often performed, with tumor being identified in 32% to 62% of the subsequent specimens. We analyzed not only the factors associated with a positive reexcision but also those factors associated with final surgical margins that are positive for tumor. METHODS: Between 1978 and 1991, 956 female patients with American Joint Committee on Cancer clinical stage I or II breast cancer were treated with breast-conserving therapy where a total of 420 patients underwent reexcision after an initial excisional biopsy. Several factors were analyzed to determine their association with a positive reexcision, the status of the final surgical margin, and the nature of the disease present within the reexcision specimen. RESULTS: Factors that correlated with a positive reexcision in both univariate and multivariate analysis were clinical tumor size, method of detection, the pathologic status of the axillary lymph nodes, and the histologic appearance. Those factors associated with finding invasive disease at the time of reexcision were clinical tumor size, clinical presentation, and nodal status. The single factor associated with finding residual in situ disease at the time of reexcision was histologic appearance of the primary tumor. A final positive margin was associated with method of tumor detection, age of the patient, and the presence of axillary lymph node metastases. CONCLUSIONS: The most significant factors associated with a positive reexcision are clinical tumor size, method of tumor detection, pathologic nodal status, and histologic appearance. Patients with larger tumors or those that are detected by physical examination, as well as invasive lobular carcinomas, may require a more generous initial resection to achieve negative surgical margins and avoid the likelihood of reexcision.

Raf-1 protein expression in human breast cancer cells.

BACKGROUND: The Raf-1 kinase, a 72-kDa cytoplasmic serine-threonine kinase, plays a central role as a second messenger in signal transduction. After ligand binding to a variety of transmembrane tyrosine kinase growth factor receptors including epidermal growth factor (EGF) receptor, the 72-kDa kinase is activated through phosphorylation to a 74-kDa phosphoprotein. The Raf-1 kinase is constitutively activated in many transformed cells either directly, by mutations within its amino-terminus regulatory region, or indirectly, due to overstimulation by autocrine growth factors or activated proximal oncogenes. The role of Raf-1 kinase in breast cancer has not been studied. METHODS: To investigate the role of Raf-1 kinase expression and its activation in breast cancer, we studied three human breast cancer cell lines expressing varying amounts of EGF receptor to determine the level of Raf-1 protein and the proportion expressed in the higher molecular weight form. Effects of serum starvation and stimulation with EGF on the Raf-1 protein were studied in T47D, BT474, and MDA-MB231 cells by precipitation of cell lysates with an anti-Raf-1 antibody followed by immunoblotting. [3H]Thymidine incorporation by these cells after EGF stimulation was also determined as a measure of DNA synthesis. RESULTS: In all three breast cancer cell lines studied, the Raf-1 protein was identified in a 70- and a 74-kDa form. The level of Raf-1 was similar in all three cell lines and appeared unrelated to EGF receptor expression on the cell surface. The majority of the protein was found in the 74-kDa form even after serum starvation. A minor shift from the lower to higher molecular weight form of Raf-1 was apparent in cells treated with EGF, and increased [3H] thymidine incorporation could be demonstrated in two of the cell lines after EGF stimulation. CONCLUSION: Baseline expression of the 74-kDa or activated form of the Raf-1 kinase appeared to be elevated in the breast cancer cells studied, indicating constitutive activation. Further investigation into the role of Raf-1 protein in the pathogenesis of breast cancer is indicated.

The influence of young age on outcome in early stage breast cancer.

PURPOSE: To assess the impact of young age on outcome in women with early stage breast cancer undergoing conservative surgery and radiation. METHODS AND MATERIALS: Between 1981 and 1991, 980 patients with Stage I and II breast cancer underwent excisional biopsy, axillary dissection, and radiation. The median follow-up was 4.6 years, with a range of 1 month to 11 years. The patients were divided into three groups, based on age at the time of diagnosis: (a) age < or = 35 years--64 patients, (b) age 36-50 years--363 patients, and (c) age > 50 years--553 patients. The comparability of the groups was assessed in terms of clinical factors (tumor size and race), histopathologic factors (histologic subtype, final resection margin, estrogen and progesterone receptor status, pathologic nodal status), and treatment related factors (reexcision, median total dose to the primary, region(s) treated with radiation, and the use of adjuvant systemic chemotherapy and/or tamoxifen). Outcome was evaluated for overall, relapse-free, and cause-specific survival and patterns of first failure (breast, regional nodes, and distant metastasis). RESULTS: There were no significant differences among the three groups in terms of race, clinical tumor size, pathology of the primary tumor, pathologic nodal status, final margin of resection, progesterone receptor status, median total dose to the primary tumor, or the regions treated. However, younger women were significantly more likely to have estrogen receptor negative tumors, undergo reexcision, and receive adjuvant systemic chemotherapy without tamoxifen. Younger women were found to have a statistically significantly decreased 8-year actuarial relapse-free survival (53% vs. 67% vs. 74%, p = 0.009), cause-specific survival (73% vs. 84% vs. 90%, p = 0.02), freedom from distant metastasis (76% vs. 75% vs. 83%, p = 0.02), and a significantly increased risk of breast recurrence (24% vs. 14% vs. 12%, p = 0.001), and regional node recurrence (7% vs. 1% vs. 1%, p = 0.0002). The patients were further divided on the basis of their pathologic nodal status. There were no statistically significant differences among the three age groups for axillary node-positive patients for overall survival (75% vs. 80% vs. 74%), relapse-free survival (73% vs. 73% vs. 62%), cause-specific survival (76% vs. 85% vs. 80%), and freedom from distant metastasis (75% vs. 75% vs. 72%), or breast recurrence (0% vs. 9% vs. 6%). The findings were identical when the analysis was restricted to node-positive patients who received chemotherapy. However, for axillary node-negative women, young age was associated with a statistically significant decreased overall survival (71% vs. 83% vs. 92%), relapse-free survival (51% vs. 65% vs. 76%), cause-specific survival (71% vs. 86% vs. 93%), freedom from distant metastasis (77% vs. 76% vs. 88%), and a statistically significant increased risk of breast recurrence (40% vs. 16% vs. 13%), and regional node recurrence (3% vs. 1% vs. 0%). The risk of a breast recurrence in axillary node-negative young women was decreased by the addition of adjuvant systemic chemotherapy but not by the use of reexcision. CONCLUSIONS: The present analysis demonstrates that young women with early stage breast cancer do significantly worse when compared to older women in terms of relapse-free survival, cause-specific survival, distant metastasis and breast and regional node recurrence. However, the adverse effect of young age on outcome appears to be limited to the node-negative patients. These findings suggest that node-negative early stage breast cancer in young women is a more aggressive disease, with an increased risk for all patterns of failure and a decreased survival.

Malignant granular cell tumors: report of a case and review of the literature.

BACKGROUND: Granular cell tumors are uncommon soft tissue tumors and are more commonly benign. Malignant granular cell tumors are extremely rare, may be confused with other soft tissue sarcomas, and can be diagnosed only when metastatic disease that has the same histologic features as the primary tumor has been identified. Metastases are more commonly seen in lymph nodes and lungs; however, often the metastatic disease is not identified at the time of initial diagnosis and presents anywhere from 3 to 37 months after initial treatment. Certain findings, such as histologic appearance and size, may suggest that a granular cell tumor has uncertain malignant potential. METHODS: We evaluated a patient with a granular cell tumor of uncertain malignant potential of the left chest wall and no evidence of metastatic disease on physical examination with a preoperative work-up to identify sites of occult disease. RESULTS: The patient was found to have suspicious ipsilateral axillary adenopathy on magnetic resonance imaging and computed tomography scan. No other regional or distant disease was identified. The patient underwent an en bloc wide excision and axillary lymph node dissection. Metastatic disease was identified in nine of 23 lymph nodes. CONCLUSIONS: Patients who are diagnosed with a granular cell tumor of uncertain malignant potential may benefit from preoperative radiologic evaluation because occult metastatic disease may be identified, alter the surgical approach, and possibly affect the long-term outcome.

Enteroenteric intussusception due to a metastatic malignant fibrous histiocytoma.

Intussusception secondary to metastatic sarcoma is an unusual cause of small bowel obstruction. When a patient who has no history of a previous laparotomy, and has a known malignancy which metastasized hematogenously, presents with small bowel obstruction, the diagnosis of intussusception should be considered. The patient should be evaluated and treated accordingly.

The role of mastectomy in patients with stage I-II breast cancer presenting with gross multifocal or multicentric disease or diffuse microcalcifications.

PURPOSE: Women with Stage I-II invasive breast cancer who present with gross multicentric disease or diffuse microcalcifications have a significant risk of breast recurrence when treated with conservative surgery and radiation. The purpose of this report is to present the results of mastectomy in this group of patients. METHODS AND MATERIALS: Between 1982 and 1989, 88 patients with clinical Stage I-II breast cancer who presented with clinical and mammographic evidence of gross multicentric disease or diffuse microcalcifications underwent modified radical mastectomy. Median followup was 4 years for the 57 patients with gross multicentric disease and 5.6 years for 31 patients with diffuse microcalcifications. At the time of mastectomy, 42% of patients were found to have positive axillary nodes. Following mastectomy, 15 patients received post mastectomy radiation and 35 patients received adjuvant systemic chemotherapy. RESULTS: When compared to a group of 1295 patients with unifocal, Stage I-II breast cancer, treated with conservative surgery and radiation during the same time period, patients with gross multicentric disease and diffuse microcalcifications had a significantly higher incidence of > or = 4 positive nodes, patients with gross multicentric disease had a lower incidence of positive resection margins following mastectomy and patients with diffuse microcalcifications were younger. The 5-year actuarial risk of an isolated local-regional recurrence was 8% for patients with gross multicentric disease or diffuse microcalcifications and 7% for patients with unifocal disease. Patients with gross multicentric disease or diffuse microcalcifications and > or = 4 positive axillary nodes who did not receive post mastectomy radiation had an increased risk for local regional recurrence. There were no significant differences in the 5-year actuarial overall or relapse-free survival (88% and 73% gross multicentric disease, 97% and 86% diffuse microcalcifications and 90% and 79% unifocal disease), freedom from distant metastasis (76% gross multicentric disease, 90% diffuse microcalcifications, 86% unifocal disease) or incidence of contralateral breast cancer (10% gross multicentric disease, 13% diffuse microcalcifications, 8% unifocal disease) among the three groups. CONCLUSION: The present study demonstrates no increased risk of local-regional recurrence in patients with gross multicentric disease or diffuse microcalcifications undergoing mastectomy in contrast to the increased risk of breast recurrence in patients with gross multicentric disease undergoing conservative surgery and radiation. Indications for post mastectomy radiation include > or = 4 positive nodes or close or positive surgical margins. Despite a significantly higher incidence of > or = 4 positive nodes, patients with gross multicentric disease and diffuse microcalcifications have a 5-year actuarial overall and relapse-free survival comparable to a group of patients with unifocal disease treated with conservative surgery and radiation.

Recurrent breast cancer: presentation, diagnosis, and treatment.

Patients must be followed up closely after primary therapy for invasive breast cancer so that locoregional recurrences can be detected early. Once a recurrence has been detected, a thorough evaluation is indicated to exclude distant metastatic disease. If none is found, the patient may be a candidate for aggressive surgical intervention to render the patient disease-free. If distant disease is found, certain sites, such as the CNS or long bones, may warrant aggressive therapy because failure to treat these sites may lead to excessive morbidity. In most situations, patients with distant disease are treated with palliative measures. In selected instances, however, patients with metastatic breast cancer are candidates for aggressive intervention, including pulmonary or liver resection or high-dose chemotherapy in combination with autologous bone marrow transplantation, to rid the patient of the disease.

Conservative surgery and radiation for early-stage breast cancer.

In selected patients with early-stage breast cancer, conservative surgery and radiation represent an alternative equal to mastectomy in terms of local recurrence, distant metastasis, survival, and long-term complications. Patients with early-stage breast cancer who are candidates for conservative surgery and radiation include those whose primary tumor is less than 4 to 5 cm in size without evidence of gross multicentricity or diffuse microcalcifications. Patients with an extensive intraductal component may be appropriate candidates provided that margins of resection are negative. Young age is not a contraindication to the conservative treatment. A preexisting history of collagen vascular disease or prior mantle irradiation for Hodgkin's or non-Hodgkin's lymphoma represents a contraindication to conservative surgery and radiation because of the potential for severe complications. An additional contraindication is the pregnant woman in whom delivery cannot be accomplished before the initiation of radiation. Mammography is essential in the pretreatment evaluation and posttreatment follow-up of the conservatively treated patient. The goal of the pretreatment mammogram is to assess the extent of disease in the ipsilateral breast as well as to evaluate the contralateral breast. In patients who present with microcalcifications, a postbiopsy mammogram before radiation is essential to document complete removal of all malignant-appearing microcalcifications. Mammography is an essential part of the follow-up program in order to detect a recurrence in the treated breast as well as a cancer in the contralateral breast cancer. The optimal interval for follow-up mammography has not been determined, although programs employing mammography on a yearly basis after treatment have been associated with the detection of early recurrences and excellent survival after salvage mastectomy for these recurrences.

Acalculous cholecystitis in bone marrow transplant patients.

BACKGROUND: Acalculous cholecystitis (ACC) is an uncommon disorder of the biliary tract, accounting for approximately 6% of acute cholecystitis cases. In this study, cholecystitis was seen in 8 of 770 bone marrow transplant recipients, with ACC occurring in five (63%). METHODS: Records of 592 allogenic and 150 autologous BMT patients were reviewed for risk factors associated with ACC. RESULTS: Only the number of blood transfusions administered and the use of total parenteral nutrition were associated with ACC development. ACC occurred in 4 of 42 (9%) allogeneic recipients who required exchange transfusion for ABO incompatibility. ACC developed in one autogolous recipient alongside venoocclusive disease of the liver. There was no association between ACC development and preparative regimen, cyclosporine usage, graft versus host disease, or cytomegalovirus infection. CONCLUSIONS: ACC occurs more frequently in patients after ABO incompatible BMT requiring exchange transfusion than in other transplant recipients.

neu(c-erbB-2/HER2) and the epidermal growth factor receptor (EGFR) in breast cancer.

One hundred and eighty thousand new cases of invasive breast cancer were diagnosed in 1992 within the United States. This disease affects approximately 1 out of 8 women in the US. Chemotherapy and/or hormonal therapy have shown some improved disease-free and/or overall survival rates. Unfortunately, this type of therapy is not directed specifically to the malignant cells, and systemic toxicities are observed. In order to develop site-specific treatment, the biology of the disease must be understood such that certain genes or their products which are involved in the pathogenesis of the disease can be targeted. Two structurally related tyrosine kinase growth factors, the epidermal growth factor receptor (EGFR) and c-erbB-2 (neu) have been identified in human breast cancer tissue and, in many instances, may function as oncogenes. The clinical data related to these two growth factor receptors as prognostic factors for the disease have been critically evaluated. Several problems with the critical studies were identified, and solutions were proposed to clarify the conflicting results reported in the studies which have attempted to examine whether c-erbB-2 (neu), in particular, is a prognostic indicator for breast cancer. In addition, data related to the structure of, ligands for and interaction between the proteins have been reviewed and presented with respect to their role in breast cancer development. A more thorough understanding of the genetic changes which contribute to the development of breast cancer will lead to more specific and less toxic treatment for this disease.

Nutritional support of patients with cancer of the gastrointestinal tract.

Malnutrition is extremely common in patients with malignant disease. Whereas the causes are multifactorial, the predominant factor is the imbalance between nutrient intake and host nutrient requirements. Furthermore, the evidence suggests that cachexia is related to abnormal changes in host intermediary metabolism induced by host-tumor interactions, and endogenous peptides such as TNF may be important mediators. The role of nutritional therapy in cancer patients remains to be defined. Clearly, patients with severe malnutrition benefit from nutritional intervention. However, the benefit of nutritional therapy in less severe cases of malnutrition as an adjuvant to oncologic therapy has yet to be established.

A G4-DNA/B-DNA junction at codon 12 of c-Ha-ras is actively and asymmetrically methylated by DNA(cytosine-5)methyltransferase.

Oligodeoxynucleotides spanning codon 12 of the human c-Ha-ras gene were found to be exceptionally good substrates for de novo methylation by human DNA(cytosine-5)methyltransferase. In the complex formed by two complementary 30mers, only the C-rich strand was methylated by the enzyme. Guanines at the 3' end of the G-rich strand of the complex could not be completely modified by dimethyl sulfate [corrected] suggesting tetrameric bonding at these G-residues. An eight-stranded structure, composed of four duplex DNAs at one end, joined to a G4-DNA segment at the other with the junction between the two DNA forms at codon 12, can account for our results.