Thus, when patients Stem Cells & Wnt inhibitor with spinal cord lesions at C3-C4 and C4-C5 levels undergo multilevel ASF, we should be alert to the possible occurrence of postoperative C5 palsy.”
“Objectives: To determine if postmenopausal women have different arterial stiffness, blood pressure (BP) values, or metabolic patterns in comparison to fertile women and to men at a population level.

Methods: This is a population-based epidemiologic study of 1853 representative men and women aged 18-95 years. Clinostatic humeral BP was measured

using Omron 705CP. Aortic BP, augmentation index (AI), and pulse wave velocity (PWV) were determined using applanation tonometry. Body mass index (BMI) and subscapular skinfold thickness were used as measures of adiposity. Fasting and postload blood glucose, homeostasis model assessment (HOMA), low-density and high-density lipoprotein serum cholesterol (LDL-C and HDL-C) and triglycerides were assessed.

Results: Age was higher in postmenopausal women than in fertile women (68.8 +/- 9.5 vs. 35.7 +/- 10.2 years, p < 0.001), and BMI was 16% higher (p < 0.01) in the

postmenopausal women after age adjustment. Humeral and aortic BP, carotid and radial AI, carotid-femoral PWV, BMI, LDL-C, LDL-C/HDL ratio, triglycerides, glucose tolerance, HOMA, and skinfold thickness were apparently higher in postmenopausal than in fertile women. Using multivariate analysis, however, AZD8186 all these differences were abolished after adjusting for confounders (age and, when appropriate, BMI), except for LDL-C, which remained 19% higher (p < 0.01) in postmenopausal women than in fertile women after adjusting for many confounders (age, BMI, cholesterol,

ethanol intake, caloric intake, and triiodothyronine).

Conclusions: Only LDL-C increases in postmenopausal women, whereas other differences attributed to menopause, including BP and arterial stiffness, seem to be confounding effects of age and BMI.”
“Background: Quantitative noninvasive imaging of myocardial mechanics in mice enables studies of the roles of individual genes in cardiac function. We sought to develop comprehensive three-dimensional methods for imaging myocardial mechanics in mice.

Methods: A 3D cine DENSE pulse sequence was implemented on this website a 7T small-bore scanner. The sequence used three-point phase cycling for artifact suppression and a stack-of-spirals k-space trajectory for efficient data acquisition. A semi-automatic 2D method was adapted for 3D image segmentation, and automated 3D methods to calculate strain, twist, and torsion were employed. A scan protocol that covered the majority of the left ventricle in a scan time of less than 25 minutes was developed, and seven healthy C57Bl/6 mice were studied.

Results: Using these methods, multiphase normal and shear strains were measured, as were myocardial twist and torsion.

(Obstet Gynecol 2013;121:136-42) DOI: http://10.1097/AOG.0b013e31827a0643″
“Background and aim: The durability of the sustained virologic response (SVR) in patients with chronic hepatitis C after treatment and the ideal follow-up time for these patients remains undefined. The objective of the Prexasertib Cell Cycle inhibitor study was to evaluate the durability of the virologic response in patients with chronic hepatitis C followed up for at least 12 months after SVR

at HCFMRP-USP. Methods: The study was conducted on 174 patients with chronic hepatitis C treated with different antiviral regimens who had achieved SVR. Qualitative serum HCV-RNA was determined by the commercial kit (COBAS AMPLICOR HCV, v2.0). Results: There was predominance of male selleck products (73%) with a mean age of 45.6 +/- 10 years. Liver cirrhosis was present in 16.1% of the study subjects. Mean follow-up time after SVR was 47 months (12-156 months). Twenty-two patients received monotherapy with interferon; 94 received interferon plus ribavirin, and 58

received pegylated interferon plus ribavirin. A total of 134 patients (77.0%) received one treatment course, 29 (16.7%) received two courses, and 11 (6.3%) received three courses. The distribution of HCV genotypes was: genotype 1 (40.2%), genotype 3 (40.8%) and genotype 2 (10.3%). Genotype was undetermined in 8.7% of cases. None of the 174 patients had recurrence of HCV infection. Two cirrhotic patients developed hepatocellular carcinoma (HCC) during follow-up. Conclusions: Among patients with SVR there was no recurrence of HCV infection or evidence of liver disease progression in any patient followed up for a 7-Cl-O-Nec1 ic50 mean of 47 months after SVR, except for patients with advanced hepatic disease before treatment,

who may develop HCC despite SVR. Therefore, one can assume that SVR is associated with long term good prognosis.”
“OBJECTIVE: To compare the surgical outcomes 12 months after laparoscopic sacrocolpopexy performed with porcine dermis and the current gold standard of polypropylene mesh.

METHODS: Patients scheduled for laparoscopic sacrocolpopexy were eligible for this randomized controlled trial. Both our clinical research nurse and the patients were blinded as to which material was used. Our primary end point was objective anatomic cure defined as no pelvic organ prolapse quantification (POP-Q) points Stage 2 or greater at any postoperative interval. Our sample size calculation called for 57 patients in each group to achieve 90% power to detect a 23% difference in objective anatomic cure at 12 months (alpha=0.05). Our secondary end point was clinical cure.

The recently discovered common molecular pathways involved in these processes are discussed.

Summary

AITDs and rheumatologic

disorders have significant commonalities both clinically and etiologically. This information is important for rheumatologists and primary care physicians who care for patients with these disorders.”
“BACKGROUND

Excision of invasive melanoma and melanoma in situ click here (MIS) using variations of the Mohs micrographic surgery (MMS) technique is becoming increasingly common in difficult areas, such as the periocular area, where standard surgical margins may not be feasible, and clinical margins are poorly defined. However, little long-term data evaluating the treatment of periocular melanoma are available in the literature.

OBJECTIVE

To present our long-term experience in the treatment of periocular melanoma

using a staged, modified Mohs excision technique with rush permanent, paraffin-embedded tissue sections.

MATERIALS AND METHODS

A total of 35 patients with periocular melanoma and MIS were treated using modified MMS during a 15-year period. Twenty-nine patients were available with adequate follow-up of greater than 5 years duration. The mean follow-up duration was 94 months.

RESULTS

There were a total of five recurrences (17.2%) detected an average of 85 months after excision. Four of the five recurrent tumors had GDC-0994 been previously excised. The recurrence rate for primary tumors was 5% (1/20). The recurrence rate for previously excised tumors was 44.4% (4/9).

CONCLUSION

Margin-control surgery is favored in the treatment of periocular melanoma to maximize the cure rate and minimize postoperative morbidity by sparing normal tissue. Ample follow-up intervals are required to adequately assess recurrence rates. The best opportunity for cure is associated with the first tumor excision.

The authors have indicated no significant interest with

commercial supporters.”
“OBJECTIVE: Recurrent pelvic organ prolapse (POP) has been attributed to many factors, one of which is lack of vaginal apical support. To assess the role of vaginal apical support and POP, we analyzed a national dataset to compare long-term reoperation rates after prolapse ABT-888 in vitro surgery performed with and without apical support.

METHODS: Public use file data on a 5% random national sample of female Medicare beneficiaries were obtained from the Centers for Medicare and Medicaid Services. Women with POP who underwent surgery during 1999 were identified by relevant International Classification of Diseases, 9th Revision, Clinical Modification, and Current Procedural Terminology, Fourth Edition codes. Individual patients were followed-up through 2009. Prolapse repair was categorized as anterior, posterior, or anterior-posterior with or without a concomitant apical suspension procedure. The primary outcome was the rate of retreatment for POP.

RESULTS: In 1999, 21,245 women had a diagnosis of POP. Of these, 3,244 (15.

The aim of this study was to examine the relationship between CrCI, CYST, beta(2)-microglobulin (B2M) and TATI, with glomerular

filtration rate (GFR) in patients with different levels of proteinuria.

Methods: Seventy-one patients (37 males, 34 females, mean age 53 +/- selleck products 15 years) were included in the study. GFR was measured by the bladder cumulative method using Tc-99m-DTPA. Blood levels of CYST, B2M and TATI were also measured. CrCI and proteinuria were determined by 24-hour urine collection. Statistical analysis was performed with multivariate analysis.

Results: The results are expressed as the ratio to GFR of CrCI and reciprocals of CYST (100/CYST), B2M (100/B2M) and TATI (100/TATI). The ratio CrCI/GFR increased from 1.41 in patients with proteinuria <1 g/ day, to 1.66 (p<0.05) in those with proteinuria >3 g/day. 1 The ratio 100/CYST/GFR selleck chemicals llc was 1.67 and 2.28 (p<0.05), 100/B2M/GFR 0.90 and 0.69 and 100/TATI/GFR 0.14 and 0.19, respectively. Multivariate analysis demonstrated that CICr/GFR as well

as 100/CYST/GFR was independently related to the degree of proteinuria.

Conclusions: CrCI and CYST overestimate GFR in patients with heavy proteinuria, while the ratios 100/TATI and 100/B2M with GFR do not significantly change. The direct measurement of GFR still remains the best method to assess the progression of renal damage in patients with heavy proteinuria.”
“P>We Crenigacestat chemical structure describe the case of a neonate who underwent surgery for bowel obstruction. The child was born at 25 weeks postconception, and at the time of surgery, he had a postconceptual age of 44 weeks. He had undergone two previous laparotomy procedures for necrotizing enterocolitis. At laparotomy, there was unexpected extensive compromise to gut perfusion. The child developed ventricular fibrillation following the reperfusion of a segment of ischemic

gut found incarcerated in an inguinal hernial orifice. We discuss the pathophysiology of intestinal ischemia-reperfusion (I-R) injury. We have reviewed the interventions that may be employed to minimize the systemic impact of I-R.”
“Background: Vitamin D (vitD) insufficiency is common in end-stage renal disease. Seasonal and ethnic differences in vitD status have been reported previously. We hypothesized that vitD status in Afro-Caribbean patients on hemodialysis (HD) living in a country with a constant sunny climate would be better than that in African-American HD patients living in countries with a winter season.

Method: A cross-sectional study was conducted in 152 Afro-Caribbean HD patients in a dialysis center located in Guadeloupe. We evaluated the prevalence of vitD insufficiency, defined as serum 25-hydroxyvitamin D (25(OH)D) levels below 30 ng/mL, compared with those results previously reported in African-American HD patients (88%).

An additive-by-additive epistatic interaction was observed between CAPN4751 and markers on the CAST gene. In conclusion, these markers should be considered for use in breeding programs.”
“Cyanidin-3-O-(2aEuro(3)-xylosyl)-glucoside (C-3-O-(2aEuro(3)-xylosyl)-G) was analyzed as an active constituent from the fruit of Siberian ginseng (Acanthopanax senticosus) using a HPLC diode array detection-electrospray ionization/mass spectrometry analysis system and the effect of C-3-O-(2aEuro(3)-xylosyl)-G on UVB-induced inflammatory signaling VX-689 price in JB6 P+ cells was investigated. C-3-O-(2aEuro(3)-xylosyl)-G inhibited UVB-induced cyclooxygenase

(COX)-2 expression and promoter binding activity in JB6 P+ cells and JB6 P+ cells stably transfected with the COX-2 luciferase reporter plasmid. It inhibited both the UVB-induced activator

protein-1 (AP-1) and nuclear factor (NF)-kappa B transactivation in JB6 P+ cells stably transfected with the AP-1 and NF-kappa B luciferase reporter plasmids. Additionally, GSK J4 research buy C-3-O-(2aEuro(3)-xylosyl)-G significantly suppressed UVB-induced upregulated phosphorylation of c-Jun N terminal kinase, MEK/extracellular signaling kinase, and mitogen activated protein kinase kinase (MAPKK) 3/6 in JB6 P+ cells. These results indicate that C-3-O-(2aEuro(3)-xylosyl)-G may be a promising chemopreventive material that acts by suppressing COX-2 expression and AP-1 and NF-kappa B transactivation and JNK, MAPKK3/6, and MEK/ERK1/2 phosphorylation.”
“We

used a micromagnetic model to study the head remanence of a perpendicular tapered main pole head. To reduce the head pole tip remanence, a single magnetic domain structure forming a vortex state from the pole tip to the tapered region is preferred. A tapered main pole structure with a trailing gap depth less than about 30 nm and a tapered angle (TG theta) equal to about 30 degrees improved the writing efficiency. This was achieved with a head field value more than 1.3 times higher and with a head field gradient about 1.15 times higher than that of the conventional AP24534 ic50 structure. Moreover, the pole tip remanence was reduced to a value closer to that of the conventional structure. The reduction in the throat height had less effect on the reduction in the head remanence in the tapered head than in the conventional head. We also discuss both single pole heads and shielded heads.”
“Purpose: To investigate the diagnostic value of quantitative determination and three-dimensional color mapping of the arterial enhancement fraction (AEF) of the liver for the detection of hepatocellular carcinoma (HCC).

Materials and Methods: This retrospective study was approved by the institutional review board; informed consent was waived. Eighty-two patients (mean age, 56.2 years +/- 10.7 [ standard deviation]), 69 men (mean age, 57.1 years +/- 10.0) and 13 women (mean age, 51.6 years +/- 13.

We found that upon deposition, a silicate and a silicon oxide layer were formed at the dielectric/silicon interface for all compositions. X-ray photoelectron spectroscopy was used to determine the band gap, as well as the energy band alignment with Si and the chemical structure of the films. Energy gap values of 6.0 +/- 0.2 and

7.5 +/- 0.2 eV were obtained for pure Sc2O3 and Tb2O3, respectively, while for the mixed layer (x=0.5) a value of 6.8 +/- 0.2 eV was extracted. It was found that the valence band offset does not change with Sc addition to Tb2O3, while the conduction band offset increases with x, from a value of 2.9 +/- 0.2 eV for the x=0 (pure Sc2O3) see more to a value of 5.7 +/- 0.2 eV for x=1 (pure Tb2O3). (C) 2010 American Institute of Physics. [doi:10.1063/1.3427554]“
“A

formula (KSS formula) containing the pith of Citrus tangerine Hort. et Tanaka (Kitsuraku), the rhizome of Zingiber officinale (Shokyo), and brown sugar has been traditionally used in China for the treatment of discomfort and cold sensation GW3965 price in the abdomen after ingestion of large amounts of alcohol. We evaluated the clinical effectiveness of this formula on signs and symptoms of alcohol hangover (AH). Of the twenty-two symptoms listed, significant decreases in severity scores were shown in nausea, vomiting, and diarrhea when the formula was administered in scheduled prophylactic doses. The score LOXO-101 in overall well-being, ranging from 0 to 100 (worst possible condition), was 68.9 +/- A 16.5 (mean +/- A SD) in the control group and it decreased to 46.9 +/- A 27.3 and to 44.4 +/- A 26.4 in the two groups that included a dosing point prior to alcohol ingestion. Regardless of dosing schedules, KSS formula did not alter the time required for complete recovery from AH symptoms. These findings suggest the possibility that KSS formula may become a candidate for AH remedy when administered prophylactically.”
“To evaluate the effectiveness of a combined intervention on knowledge, attitude, and practice (KAP) of people with epilepsy and their families

in rural areas of China, random samples of people with epilepsy and their family members from the intervention populations completed questionnaires prior to the intervention (2002, N = 975) and 2 years later (N = 950). There was no significant difference in important demographic variables between the two samples. KAP levels of patients and their family members improved over the study period. Worry about seizures, discrimination, and medical costs are the principal factors in patients’ psychological burden. Psychological burden and inability to concentrate at work are the main influences of the disease on family members. Reduction of the psychological burden of patients and their family members is a significant aspect of treatment to which more attention should be paid in similar future interventions. (c) 2009 Elsevier Inc. All rights reserved.

On the other hand, statistically, a significant relationship was found between patients with positive lymph nodes and patients with negative lymph nodes in terms of preoperative CA125 values, the positivity or negativity of peritoneal washings and histological types of tumors.

Discussion We could not determine any effects of preoperative CA125 values, histological type of tumor and peritoneal cytology on the number of positive lymph nodes.

Pelvic and para-aortic lymphadenectomy must be performed for us until the factors that affect nodal involvement will be described further in larger and more comprehensive RAD001 mouse studies.”
“Plants present various advantages for the production of biomolecules, including low risk of contamination with prions, viruses and other pathogens, scalability, low production costs, and available agronomical systems. Plants are also versatile vehicles for the production of recombinant molecules because they allow protein expression in various organs, such as tubers and seeds, which naturally accumulate large amounts of protein. Among crop plants, soybean is

an excellent protein producer. Soybean plants are also a good source of abundant buy KU-57788 and cheap biomass and can be cultivated under controlled greenhouse conditions. Under containment, the plant cycle can be manipulated and the final seed yield can be maximized for large-scale protein production within a small and controlled area. Exploitation of specific regulatory sequences capable of directing and accumulating recombinant proteins in protein storage vacuoles in soybean seeds, associated with recently developed biological Cyclosporin A mouse research tools and purification systems, has great potential to accelerate preliminary characterization of plant-derived biopharmaceuticals and industrial macromolecules. This is an important step in the development of genetically engineered products that are inexpensive and safe for medicinal, food and other uses.”
“Laser peen forming, is a purely mechanical forming method achieved through the use of laser energy to form complex shapes or modify curvatures.

It is flexible and independent of tool inaccuracies that result from wear and deflection. Its nonthermal process makes it possible to form sheet metal without material degradation or even improve them by inducing compressive stress over the target surface. Experimental investigation has been carried out to understand the effect of process parameters such as laser intensity, scanning velocity on the bending deformation of thin sheet metal with different thicknesses. It is found that the sheet metal can be made to bend not only toward but also away from the laser beam depending on the process condition. The bending deformation is found to be varied continuously and smoothly from the concave form to the convex by increasing the sheet thickness or decreasing the laser intensity. There is also a specific thickness for sheet metal to remain flat after laser peen forming.

01) were important to rosuvastatin concentration (adjusted R-2=0.56 for the final model). Atorvastatin concentration was associated with SLCO1B1 c.388A>G (P<0.01) and c.521T>C (P<0.05) and 4-hydroxycholesterol, a CYP3A activity marker (adjusted R-2=0.47). A second cohort of 579 patients from primary and specialty care

databases were retrospectively genotyped. In this cohort, genotypes associated MG-132 mechanism with statin concentration were not differently distributed among dosing groups, implying providers had not yet optimized each patient’s risk-benefit ratio. Nearly 50% of patients in routine practice taking the highest doses were predicted to have statin concentrations greater than the 90th percentile.

Conclusions

Interindividual variability in statin exposure in patients is associated with uptake and efflux transporter polymorphisms. An algorithm incorporating genomic and clinical variables to avoid high atorvastatin and rosuvastatin levels is described; further study will determine whether this approach

reduces incidence of statin myopathy.”
“Recent years have seen a rising awareness of the significance of cardiac antibody-mediated rejection (AMR) as a result of its formal Epigenetics inhibitor recognition by the International Society for Heart and Lung Transplantation. New insights on the pathology and clinical behavior of cardiac AMR are at odds with current diagnostic guidelines. This perspective examines some of the contentious and unresolved issues in cardiac AMR as the transplant community makes concrete steps towards updating its defining criteria. J Heart Lung Transplant 2010;29:389-394 (C) 2010 International Society for Heart and Lung Transplantation. All rights reserved.”
“Patients with suspected or confirmed 17DMAG research buy osteosarcoma should be evaluated and treated at a comprehensive cancer center within a multidisciplinary sarcoma program that includes pediatric, medical and radiation oncologists, orthopedic and surgical oncologists, musculoskeletal pathologists, and radiologists.

Successful treatment involves proper diagnosis, neoadjuvant and adjuvant multi-agent chemotherapy, and aggressive surgery with an emphasis toward limb-preserving procedures. Treatment of osteosarcoma should be undertaken within the framework of large cooperative group clinical trials for children, adolescents, and adults. Patients treated with osteosarcoma should be followed closely both for recurrence of disease and for development of late effects of the treatment of their cancer. The treatment of metastatic, recurrent and/or refractory disease is more controversial. Despite advances in systemic treatment, surgical technique, and supportive care, the overall outcome is still poor.”
“Contact resistance measurements are reported for radio frequency microelectromechanical system switches operating in an ultrahigh vacuum system equipped with in situ oxygen plasma cleaning capabilities.

During pulmonary procedures in patients with LVADs, special attention should be paid

to hemodynamics because lung resection surgery requires a lateral decubitus position, single-lung ventilation and postoperative decrease in the pulmonary vascular bed, all of which may lead to inadequate preload to the LVAD. We present a case of lower lobectomy of the left lung for an adenocarcinoma found in a patient with an implantable continuous-flow LVAD. (c) 2011 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.”
“Background: We studied the association of causes and stroke outcome of stroke in the E7080 young in Thailand. Methods: A retrospective study was performed at Srinagarind Hospital, Khon Kaen University, Thailand. All patients under 45 years of age who were diagnosed with stroke between 1996 and 2010 and who had complete workups for causes of stroke in the young were enrolled. Stroke outcome was defined as favorable or nonfavorable at approximately 1 year of follow-up. If the patient had normal functional ability or mild disability but the patient was fully employed, the outcome was classified as favorable. Clinical features of strokes and the potential stroke risk factors were compared between the favorable and nonfavorable groups. Results: Eighty-five patients selleck screening library were enrolled. About half of patients were male selleckchem (47 patients; 55.3%). The

mean age (SD) was 35.9 (6.2) years. Three-fourths of male patients had a stroke after 30 years of age, while female patients developed stroke in all age ranges equally. More than half of patients (45 patients; 52.9%) had cardiac causes of stroke. Rheumatic mitral stenosis accounted for 68% (31 patients), and 45% (14 patients) had atrial fibrillation. There were 64 patients (79%) who had a favorable outcome. Cardiac causes, particularly mitral stenosis and alcohol intake, were significantly associated with a nonfavorable outcome. Conclusions: Stroke in the young generally has a favorable outcome. Factors associated with a nonfavorable outcome of stroke in the young were cardiac abnormalities

and alcohol intake. A prospective study to evaluate the association of causes and outcome is needed.”
“Background: The effect of intramedullary reaming on diaphyseal tibial defects has not been examined in the literature. The present aim was to relate the extent of reaming to angiogenesis and bone formation occurring around a critical-sized defect in the tibia for two scenarios, namely, when the bone defect is left empty and when the bone defect is treated with autograft.

Methods: Eleven canines were allocated into two groups, namely, empty (n = 5) or iliac crest autograft (n = 6). All tibiae were reamed to 7.0 mm and fixed with a 6.5-mm statically locked intramedullary nail after creation of an 8.0-mm diaphyseal defect.

The emission spectra of Nd3+:Y2O3 were taken by exciting the nanoparticles before and after entering the whole blood sample. The emission from the F-4(3/2) -> aEuro parts per thousand I-4(11/2) manifold transition of Nd3+:Y2O3 nanoparticles readily propagates through the blood sample at excitation of 808 nm and exhibits a shift in relative intensities of the peaks due to differences in scattering.

At 808 nm, in both whole blood and plasma samples, a direct relationship was found with absorption coefficient and Y2O3 nanoparticle concentration. Results for the whole blood indicate a small inverse relationship with Y2O3 nanoparticle concentration and check details scattering coefficient and in contrast a direct relation for the plasma.”
“A 16-year-old Hispanic girl with arrhythmogenic right-ventricle dysplasia (ARVD) presented with angina pectoris and troponin increase on three occasions. There was a family history of sudden cardiac death in a cousin. Her mother was diagnosed with ARVD. The patient herself had a history of nonsustained ventricular tachycardia but did not

meet diagnostic criteria for ARVD. Cardiac workup, including serial transthoracic echocardiograms and a coronary angiogram, showed a structurally normal heart without coronary artery stenosis. Results of cardiac magnetic resonance imaging were questionable, but endomyocardial biopsy did not show evidence of viral myocarditis by polymerase chain reaction. Genetic testing confirmed ARVD.”
“The aim of this study was to determine the prevalence of chronic disease Savolitinib mouse and the risk factors for herpes zoster infection. BVD-523 manufacturer In this case-control study medical records were collected

from 55 patients who presented with herpes zoster and 54 patients in a control group who presented with gastroenterocolitis. Both groups were treated at the Clinic for Infectious Diseases, University Clinical Hospital Mostar from January, 2005 to December, 2010. When we compared the herpes zoster group with the control group, we did not demonstrate any significant difference in the overall prevalence of chronic diseases. However, the prevalence of diabetes and cancer was statistically higher when compared to the control group. A statistically significant difference in the number of cigarette smokers was not observed, whereas the number who consumed alcohol in the herpes zoster group was significantly higher compared to the control group. The correlation between alcohol and herpes zoster could help in solving the reactivation mechanism of VZV. (C) Versita Sp. z o.o”
“Transition metals and polycyclic aromatic hydrocarbons (PAHs) are cocontaminants at many sites. Contaminants in mixtures are known to interact with biological systems in ways that can greatly alter the toxicity of individual compounds.