A copper-based metal-organic framework decorated with electrodeposited Fe2O3 nanoparticles for electrochemical nitrite sensing.

An amperometric nitrite sensor is reported based on a screen-printed carbon electrode (SPCE) modified with copper(II)-benzene-1,4-dicarboxylate (Cu-BDC) frameworks and iron(III) oxide nanoparticles (Fe2O3 NPs). First, copper(I) oxide (Cu2O) nanocubes were synthesized, followed by a solvothermal reaction between Cu2O and H2BDC to form square plate-like Cu-BDC frameworks. Then, Fe2O3 NPs were electrodeposited on Cu-BDC frameworks using a potentiostatic method. The Fe2O3@Cu-BDC nanocomposite benefits from high conductivity and large active surface area, offering excellent electrocatalytic activity for nitrite oxidation. Under optimal amperometric conditions (0.55 V vs. Ag/AgCl), the sensor has a linear range of 1 to 2000 µM with a detection limit of 0.074 µM (S/N = 3) and sensitivity of 220.59 µA mM-1 cm-2. The sensor also provides good selectivity and reproducibility (RSD = 1.91%, n = 5). Furthermore, the sensor exhibits long-term stability, retaining 91.4% of its original current after 4 weeks of storage at room temperature. Finally, assessing nitrite in tap and mineral water samples revealed that the Fe2O3@Cu-BDC/SPCE has a promising prospect in amperometric nitrite detection.

Voltammetric determination of iodide in iodized table salt using cetyltrimethylammonium bromide as ion-pairing.

In this work, voltammetric study based on cetyltrimethylammonium bromide (CTAB) as an ion-pairing agent for the determination of iodine level in iodized table salt has been explored. CTAB was used as an intermediate compound between iodide (I-) and the electrode due to its ability to dissociate to produce cetyltrimethylammonium ions ([CTA]+). The [CTA]+ with a long hydrophobic alkyl chain can be directly adsorbed onto the surface of the working electrode, and this in turns coated the electrode with cationic charge and enhance the electrode ability to bind to iodide (I-) and other molecular iodine ions. A mixture of iodide and CTAB ([CTA]+I-) was prepared and potential of 1.0 V for 60.0 s was applied to pre-concentrate the solution on the working electrode causing the [CTA]+I- to oxidize to iodine (I2). The produced I2 immediately react with chloride ion (Cl-) from the electrolyte of hydrochloric acid (HCl) to produce I2Cl- and form ion-pair with CTA+ as [CTA]+I2Cl-. The linear calibration curve of the developed method towards iodide was in the concentration range of 0.5-4.0 mg/L with sensitivity of - 1.383 µA mg/L-1 cm-2 (R2 = 0.9950), limit of detection (LOD) of 0.3 mg/L and limit of quantification (LOQ) of 1.0 mg/L, respectively. The proposed method indicates good agreement with the standard method for iodine determination with recovery range from 95.0 to 104.3%. The developed method provided potential application as a portable on-site iodine detector.

Quantitative assessment of wound healing using high-frequency ultrasound image analysis.

PURPOSE: We aimed to develop a method for quantitative assessment of wound healing in ulcerated diabetic feet. METHODS: High-frequency ultrasound (HFU) images of 30 wounds were acquired in a controlled environment on post-debridement days 7, 14, 21, and 28. Meaningful features portraying changes in structure and intensity of echoes during healing were extracted from the images, their relevance and discriminatory power being verified by analysis of variance. Relative analysis of tissue healing was conducted by developing a features-based healing function, optimised using the pattern-search method. Its performance was investigated through leave-one-out cross-validation technique and reconfirmed using principal component analysis. RESULTS: The constructed healing function could depict tissue changes during healing with 87.8% accuracy. The first principal component derived from the extracted features demonstrated similar pattern to the constructed healing function, accounting for 86.3% of the data variance. CONCLUSION: The developed wound analysis technique could be a viable tool in quantitative assessment of diabetic foot ulcers during healing.

Musculoskeletal disorder (MSD) among agricultural workers.

Farming is a large and main industry in Bangladesh. Large numbers of people are directly involved in farming and have very unique exposure compare to other sectors. Musculoskeletal problems among farmer population are not infrequent. This study was carried out among 200 farmers in one selected district. The study revealed that musculoskeletal problems were common among the farmers working in a traditional way. All the respondents were male. The age of all respondents lie between 20-60 years. Among them 22.5% farmers were illiterate, about 45.5% below Class V. About half (42%) of the respondents had reported pain in different parts of the body at least one or more times during working in land. And about two third (65.5%) of the farmers had history of joint pain and stiffness in last 12 month. Most of the farmers who suffered from musculoskeletal symptoms were 41-60 years. Specially who worked more then 20 years (82.6%) and average 6 hours per day (66.7%). The occurrence of musculoskeletal problems in various part of the body included Knee pain - 48.1%, Back pain (back ache) - 22.9%, Waist pain (low back ache) - 13.3%, Neck pain - 18.3% and shoulder pain - 10.7%. Length of work in year and daily average working hours were found significant association with musculoskeletal pain. It was found that musculoskeletal pain were more common among the farmers when they worked in squatting position (52%) and specially during weeding of plants (31%). Among them only 22% also engaged in other business. Most of the farmers complained dull aching pain (40.6%), only 2.3% noticed severe acute pain, but about 86% farmers' temporary stop their work for pain and 80% get relief after discontinue of work. About 75% respondents visited doctors for their pain which was statistically significant (p=0.001). It was found that the rates of musculoskeletal complaints are more among those individuals who worked relatively bad ergonomic condition, such as body position probably play an important role.

Isolation and characterization of a phenol-degrading Rhodococcus sp. strain AQ5NOL 2 KCTC 11961BP.

In this work, we report on the isolation of a phenol-degrading Rhodococcus sp. with a high tolerance towards phenol. The isolate was identified as Rhodococcus sp. strain AQ5NOL 2, based on 16S rDNA analysis. The strain degraded phenol using the meta pathway, a trait shared by many phenol-degraders. In addition to phenol biodegradation, the strain was also capable of degrading diesel. Strain AQ5NOL 2 exhibited a broad optimum temperature for growth on phenol at between 20 °C and 35 °C. The best nitrogen sources were ammonium sulphate, glycine or phenylalanine, followed by proline, nitrate, leucine, and alanine (in decreasing efficiency). Strain AQ5NOL 2 showed a high tolerance and degradation capacity of phenol, for it was able to register growth in the presence of 2000 mg l(-1) phenol. The growth of this strain on phenol as sole carbon and energy source were modeled using Haldane kinetics with a maximal specific growth rate (µ(max)) of 0.1102 hr(-1), a half-saturation constant (K(s) ) of 99.03 mg l(-1) or 1.05 mmol l(-1), and a substrate inhibition constant (K(i)) of 354 mg l(-1) or 3.76 mmol l(-1). Aside from phenol, the strain could utilize diesel, 2,4-dinitrophenol and ρ-cresol as carbon sources for growth. Strain AQ5NOL 2 exhibited inhibition of phenol degradation by Zn(2+), Cu(2+), Cr(6+), Ag(+) and Hg(2+) at 1 mg l(-1).

The use of normalized cross-correlation analysis for automatic tendon excursion measurement in dynamic ultrasound imaging.

The work describes an automated method of tracking dynamic ultrasound images using a normalized cross-correlation algorithm, applied to the patellar and gastrocnemius tendon. Displacement was examined during active and passive tendon excursions using B-mode ultrasonography. In the passive test where two regions of interest (2-ROI) were tracked, the automated tracking algorithm showed insignificant deviations from relative zero displacement for the knee (0.01 ± 0.04 mm) and ankle (-0.02 ± 0.04 mm) (P > .05). Similarly, when tracking 1-ROI the passive tests showed no significant differences (P > .05) between automatic and manual methods, 7.50 ± 0.60 vs 7.66 ± 0.63 mm for the patellar and 11.28 ± 1.36 vs 11.17 ± 1.35 mm for the gastrocnemius tests. The active tests gave no significant differences (P > .05) between automatic and manual methods with differences of 0.29 ± 0.04 mm for the patellar and 0.26 ± 0.01 mm for the gastrocnemius. This study showed that automatic tracking of in vivo displacement of tendon during dynamic excursion under load is possible and valid when compared with the standardized method. This approach will save time during analysis and enable discrete areas of the tendon to be examined.

Status of blood pressure among individuals consuming saline water.

Climate change is taking its toll in the form of saline water intrusion into the mainland of Bangladesh, which is one of the lowest-altitude countries in the world. The study was carried out with the objective to assess the blood pressure status associated with salinity in saline prone selected areas of Bagherhat and Tangail districts from March 2008 - June 2008 of rural Bangladesh. Two hundred and ninety subjects were selected purposively from both the districts. About 70% of the respondents were males and below forty years of age. More than two thirds of the respondents were illiterate; belong to 4-5 member family, with monthly family income of less than Tk. 4000 per month. Only one third of the respondents were smokers. More than two thirds of the respondents from salinity area had salinity level of 2-3%. Among them majority were drinking saline water for 6-10 years and 26% were drinking for more than ten years. About 20% of the non saline respondents' systolic blood pressure was 110-120 mm of Hg and 26% of saline area had systolic blood pressure >135-140 mm of Hg. Mean systolic BP among salinity area was more than that for non salinity area. About 19% of the non saline respondents' diastolic blood pressure was ≤ 85 mm of Hg. About one third had ≥ 90 mm of Hg, among them 31% were from saline area. Mean diastolic BP among salinity area was more than non salinity area. There was no history of heart disease, and less than 1% was diabetic among them. About two thirds had mean arterial pressure <70 mm of Hg, among them majority were from non saline area. About one third had >70 mm of Hg, among them majority were from saline area. The study concluded that systolic and diastolic blood pressures of saline group were significantly higher than that of the non saline group.

Knowledge about inhaler use among the chronic asthma patients in selected hospitals.

This cross sectional descriptive study was conducted among the chronic asthma patients attending three Institutes of Dhaka city namely National Asthma Center, The National Institute of Diseases of Chest and Hospital (NIDCH), Mohakhali, and Dhaka Medical College Hospital to assess the level of knowledge regarding inhaler use. Convenient sampling was adopted. Data were collected using one semi-structured questionnaire through face-to-face interview. The patients were aged from 18 to 75 years with mean age being 40.68 years and sd +/- 11.659 years. The mean monthly income of the respondents found was 8278.52 taka with standard deviation +/- 3523.315 taka. Mean duration of bronchial asthma was 9.44 years with sd +/- 4.862 years. Out of the total 298 respondents 103(35.8%) possessed "excellent knowledge" on inhalers. Ninety one (31.6%) had "adequate knowledge", sixty nine (24.0%) had "poor knowledge" and thirty five (8.7%) respondents were found having "no knowledge" about inhalers. Males were seen having better knowledge than the females (chi2 =66.582, df=3, p<0.001). The respondents receiving treatment from the indoor possessed better knowledge than those from the outdoors (p<0.001). Level of Knowledge was also found to be associated with the educational status of the respondents. Respondents with higher education possessed more than the respondents with lower education (p<0.001). Though most of the physicians now prescribe inhalers, but many of them do not explain the proper use of inhaler. This may be corrected through training and motivation of physicians at Medical Colleges and Hospitals and during various medical conferences and other programs. To reduce the extent of suffering and economic burden of asthma patients and their families, active education program for the patients and training program for the health care providers, regarding "inhaler use technique" demands early consideration.

Molybdate reduction by Pseudomonas sp. strain DRY2.

AIMS: To isolate and characterize a potent molybdenum-reducing bacterium. METHODS AND RESULTS: A minimal salt medium supplemented with 10 mmol l(-1) molybdate, glucose (1.0%, w/v) as a carbon source and ammonium sulfate (0.3%, w/v) as a nitrogen source was used in the screening process. A molybdenum-reducing bacterium was isolated and tentatively identified as Pseudomonas sp. strain DRY2 based on carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. Strain DRY2 produced 2.4, 3.2 and 6.2 times more molybdenum blue compared to Serratia marcescens strain DRY6, Enterobacter cloacae strain 48 and Eschericia coli K12, respectively. Molybdate reduction was optimum at 5 mmol l(-1) phosphate. The optimum molybdate concentration that supported molybdate reduction at 5 mmol l(-1) phosphate was between 15 and 25 mmol l(-1). Molybdate reduction was optimum at 40 degrees C and at pH 6.0. Phosphate concentrations higher than 5 mmol l(-1) strongly inhibited molybdate reduction. Inhibitors of electron transport system such as antimycin A, rotenone, sodium azide and cyanide did not inhibit the molybdenum-reducing enzyme activity. Chromium, copper, mercury and lead inhibited the molybdenum-reducing activity. CONCLUSIONS: A novel molybdenum-reducing bacterium with high molybdenum reduction capacity has been isolated. SIGNIFICANCE AND IMPACT OF THE STUDY: Molybdenum is an emerging global pollutant that is very toxic to ruminants. The characteristics of this bacterium suggest that it would be useful in the bioremediation of molybdenum pollutant.

Correlation between Breast Self-Examination Practices and Demographic Characteristics, Risk Factors and Clinical Stage of Breast Cancer among Iraqi Patients.

BACKGROUND: Breast Cancer (BC) is the most common cancer and the leading cause of cancer death among women globally. The disease can be cured with limited resources if detected early. Breast self-examination (BSE) is considered a cost-effective feasible approach for early detection of that cancer in developing countries. AIM: To determine the correlation between BSE performance and demographic characteristics, risk factors and clinical stage of BC among Iraqi patients. METHODS: This retrospective study included a total of 409 female patients diagnosed with BC at the Referral Training Center for Early Detection of Breast Cancer and the National Cancer Research Center in Baghdad. The studied variables included the age of the patient, occupation, marital and educational status, parity, history of lactation, contraceptive pill intake, family history of cancer and the clinical stage of the disease. RESULTS: Our findings revealed that the most important predictors for practicing BSE was family history of BC or any other cancers (OR = 3.87, P = 0.018) followed by being a governmental employee (OR = 1.87, P = 0.024), history of contraceptive use (OR = 1.80, P = 0.011) and the high level of education (OR = 1.73, P = 0.004). On the other hand, there was no significant correlation between the practice of BSE and the BC stage at the time of presentation. CONCLUSION: There is a relatively poor practice of BSE among Iraqi patients diagnosed with BC. It is mandatory to foster the national cancer control strategies that focus on raising the level of awareness among the community through public education as a major approach to the early detection of cancer in Iraq.

Measurement of natural radioactivity and dose rate assessment of terrestrial gamma radiation in the soil of southern Punjab, Pakistan.

Activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in soil samples collected from the most populous area of southern Punjab of Pakistan have been measured by gamma-ray spectrometry. The measured activity concentrations for these radionuclides are compared with the reported data from different other countries and it is found that measured activity concentrations are comparable with the worldwide measured average values reported by the UNSCEAR. Subsequently assessed radiological effects show that the mean radium equivalent activity (Ra(eq)) is 96.7 +/- 15.2 Bq kg(-1) and air absorbed dose rate (D) is 46.1 +/- 7.3 nGy h(-1). The values of internal and external radiation hazard indices are found to be less than unity. The annual effective radiation dose is calculated to be 0.28 +/- 0.05 mSv, which is well below the limit of 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection, for the general public.

Status of Hearing Impairment among Handloom Workers in Tangail District of Bangladesh.

Industrial noise is one of the major sources of noise pollution. Handloom industry is the biggest handicraft industry in our country; it is the second largest source of rural employment after agriculture. The workers of the handloom industry worked within excessive level of sound. This cross-sectional study was an attempt to see the status of hearing impairment among handloom worker at Tangail District, Bangladesh from August 2016 to December 2016. A total 180 handloom workers were included in this current study. All the respondents were male as handloom work is a strenuous work. The mean age of respondents was 38.18±11.529 years where most of the respondents were of middle age group (21-50) year's age group. Among the participants less than one-fourth was illiterate and rest had primary to secondary level of education. The average income of handloom workers was 13805.56±2764.696 BDT per month. Handloom workers spend average 10 hour for working per day. They were exposed to sound beyond NIOSH recommendation (70-83 dB around handloom machines and 80-90 dB around power loom machines). By self-assessment hearing impairment perception 76.7% participants reported that they had hearing problem. Based on the interpretation of Rinne, Webers and ABC test data indicate that among the respondents around 32.2% were identified with bilateral sensorineural hearing impairment and of them through Pure tone audiometry (PTA) around half were diagnosed as suffering from moderate to severe Noise induced hearing loss (NIHL). Using personal protective measure like ear muffle/ear musk has been recommended.

EMG Processing Based Measures of Fatigue Assessment during Manual Lifting.

Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs), where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG) signal is used to monitor the workers' muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird's eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications.

Tube Feed Necrosis after Major Gastrointestinal Oncologic Surgery: Institutional Lessons and a Review of the Literature.

BACKGROUND: Small bowel necrosis after enteral feeding through a jejunostomy tube (tube feed necrosis, TFN) is a rare, serious complication of major abdominal surgery. However, strategies to reduce the incidence and morbidity of TFN are not well established. Here, in the largest series of TFN presented to date, we report our institutional experience and a comprehensive review of the literature. METHODS: Eight patients who experienced TFN from 2000 to 2014 after major abdominal surgery for oncologic indications at the University of Cincinnati were reviewed. Characteristics of post-operative courses and outcomes were reviewed prior to and after a change in tube-feeding protocol. The existing literature addressing TFN over the last three decades was also reviewed. RESULTS: Patients with TFN ranged from 50 to 74 years old and presented with upper gastrointestinal tract malignancies amenable to surgical resection. Six and two cases of TFN occurred following pancreatectomy and esophagectomy, respectively. Prior to TF protocol changes, which included initiation at a low rate, titrating up more slowly and starting at one-half strength TF, three of six cases of TFN (50%) resulted in mortality. With the new TF protocol, there were no deaths, goal TF rate was achieved 3 days later, symptoms of TFN were recognized 3 days earlier, and re-operation was conducted 1 day earlier. CONCLUSION: This case series describes a change in clinical practice that is associated with decreased morbidity and mortality of TFN. Wider implementation and further refinement of this tube-feeding protocol may reduce TFN incidence at other institutions and in patients with other conditions requiring enteral nutrition.

The effects of angiopoietin-1 and -2 on tumor growth and angiogenesis in human colon cancer.

Angiopoietin (Ang) 1 and Ang-2 are important regulators of endothelial cell survival. Current models suggest that an increase in Ang-2 expression in endothelial cells leads to initiation of angiogenesis. We stably transfected HT29 colon cancer cells with cDNA constructs for Ang-1 or -2 or with vector alone, injected the cells s.c. into nude mice, and assessed tumor growth. Immunohistochemical analyses confirmed sustained increases of Ang-1 and -2 in the tumors. The tumors produced by the Ang-2-transfected cells were larger than the tumors produced in the other groups; those tumors also had higher vessel counts and proliferative indices than tumors in the other groups. Tumors produced by the Ang-1 transfectants had fewer vessels and lower tumor cell proliferative indices than tumors in the other groups. These data suggest that imbalances between Ang-1 and -2 that result in a net gain of Ang-2 activity lead to enhanced tumor angiogenesis and growth.

Management of genital warts in women with human leukocyte interferon-alpha vs. podophyllotoxin in cream: a placebo-controlled, double-blind, comparative study.

The purpose of this double-blind, placebo-controlled, comparative study was to evaluate the specific clinical efficacy and tolerance of human leukocyte interferon-alpha (2 x 10(6) IU/g) and podophyllotoxin 0.5% incorporated in a hydrophilic cream to cure genital warts. Preselected Asian women (n = 60) aged 18-40 years (mean 22.9), with a clinical and biopsy-confirmed diagnosis of genital warts, harboring 322 lesions (mean 5.36) were randomly assigned to three parallel groups to receive one of the two test drugs or placebo. Each patient received a precoded tube (40 g) containing either human leukocyte interferon-alpha, podophyllotoxin, or identically appearing placebo cream for 3 days' usage. In addition to written instructions, each subject was shown how to apply a minimal amount of trial medication on their lesions thrice daily for 3 consecutive days per week (maximum nine topical applications per week). Patients were examined on a weekly basis, and a cure was considered to be a biopsy-confirmed, total elimination of a lesion. Moreover, patients cured during the study period were spared further therapy, and were requested to return in 16 weeks to monitor for the occurrence of a relapse. The remaining patients' empty tubes were collected, and similarly precoded replacement tubes were given to continue the treatment; a total of 214 tubes were used. The study was scheduled for 16 weeks with 4 weeks of active treatment. Individuals were excluded from the study due to pregnancy, breast feeding, or the receiving of any type of antiviral therapy during the 4 weeks preceding enrollment.(ABSTRACT TRUNCATED AT 250 WORDS)

Human leukocyte interferon-alpha in cream for the management of genital herpes in Asian women: a placebo-controlled, double-blind study.

This double-blind, placebo-controlled study examined the clinical efficacy and tolerance of human leukocyte interferon-alpha (2 x 10(6) IU/g) in hydrophilic cream to cure patients afflicted with first episodes of genital herpes. Sixty patients aged 18-40 years (mean 24.5) with culture-confirmed herpes simplex genitalis, bearing 755 lesions (mean 12.6) were randomized to active and placebo groups. Patients joined the study within 7 days (mean 4.1) of the manifestation of lesions. Each patient was given a precoded 40-g tube containing placebo/active preparation with instructions on self-application of the trial medication to their lesions three times daily for 5 consecutive days (max. 15 topical applications per week). Patients were examined three times a week to evaluate clinical efficacy and other beneficial effects. A reepithelialized lesion with some residual erythema was recorded as healed. Patients resolved during the active treatment period (1-4 weeks) were spared further therapy and were requested to visit us as scheduled for posttreatment control after 16 weeks. From the remaining patients empty tubes were collected, and similarly coded replacement tubes were given to continue the treatment (in total 160 tubes were used). Patients treated with leukocyte interferon-alpha cream had significantly shorter mean duration of viral shedding/healing than placebo recipients, (6.2 days vs. 15 days; P < 0.01); thus the number of healed patients was 25/30 (83.3%) vs. 5/30 (17%; P < 0.001. Of the 60 patients 49 (81.6%) complained no drug-related side effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertension and arsenic exposure in Bangladesh.

-A prevalence comparison of hypertension among subjects with and those without arsenic exposure through drinking water was conducted in Bangladesh to confirm or refute an earlier observation of a relation in this respect. Wells with and without present arsenic contamination were identified, and we interviewed and examined 1595 subjects who were depending on drinking water from these wells for living, all >/=30 years of age. The interview was based on a questionnaire, and arsenic exposure was estimated from the history of well-water consumption and current arsenic levels. Of the 1595 subjects studied, 1481 had a history of arsenic-contaminated drinking water, whereas 114 had not. Time-weighted mean arsenic levels (in milligrams per liter) and milligram-years per liter of arsenic exposure were estimated for each subject. Exposure categories were assessed as <0.5 mg/L, 0.5 to 1.0 mg/L, and >1.0 mg/L and alternatively as <1.0 mg-y/L, 1.0 to 5.0 mg-y/L, >5.0 but 10.0 mg-y/L, respectively. Hypertension was defined as a systolic blood pressure of >/=140 mm Hg in combination with a diastolic blood pressure of >/=90 mm Hg. Corresponding to the exposure categories, and using "unexposed" as the reference, the prevalence ratios for hypertension adjusted for age, sex, and body mass index were 1.2, 2.2, 2.5 and 0.8, 1.5, 2.2, 3.0, in relation to arsenic exposure in milligrams per liter and milligram-years per liter, respectively. The indicated dose-response relationships were significant (P<<0.001) for both series of risk estimates. These results suggest that arsenic exposure may induce hypertension in humans.

Overview of angiogenesis: Biologic implications for antiangiogenic therapy.

Tumor angiogenesis is essential for the growth of primary and metastatic tumors. This process requires the coordinated activities of multiple factors and cell types. For tumors to develop a neovascular blood supply, tumor cells and host cells must secrete proangiogenic factors that offset the activities of inhibitory angiogenic factors. In addition, the newly derived tumor endothelium must respond to signals in the microenvironment to survive under conditions such as hypoxia and acidity. Moreover, because the process of angiogenesis is regulated by redundant factors and pathways, inhibition of any single pathway is likely to select for cells whose angiogenesis is driven by other factors. Because antiangiogenic therapy is unlikely to induce tumor regression, the criteria for efficacy must be evaluated by means other than the standard criteria used to evaluate cytotoxic chemotherapy. Understanding the basic principles that drive tumor angiogenesis will lead to the development of therapies that will likely prolong survival without the toxicity associated with standard chemotherapy.