Propensity score matching confirms that primary surgery or neoadjuvant chemotherapy result in equivalent survival within a comprehensive cohort of patients with high-grade serous ovarian cancer.

OBJECTIVE: Our objective was to investigate whether trial evidence showing that neoadjuvant chemotherapy is non inferior to primary surgery for the primary treatment of advanced ovarian cancer could be extrapolated to groups of patients that were not included in the trials. METHODS: Using a detailed retrospective cohort of all patients managed through a single tertiary hospital we carried out a propensity score analysis, principal component analysis, and cox proportional hazard analysis to compare survival in matched cohorts. RESULTS: A propensity score analysis showed that for at least 41% of all patients with advanced high-grade serous cancer neoadjuvant chemotherapy is non inferior to primary surgery (median survival primary surgery: 38 months, neoadjuvant chemotherapy: 35 months. P = 0.39). However, principal component analysis, supported by cox modelling, suggests that for some subgroups, including patients with subdiaphragmatic nodal disease, primary surgery may be associated with improved survival (HR 0.11, CI 0.026-0.48). CONCLUSIONS: We have shown that the findings of previous trials can be extrapolated to a wider population and that statistical modelling can be used to identify groups or patients who benefit from specific modalities of treatment.

Initial clinical experience with high-pitch dual-source CT as a rapid technique for thoraco-abdominal evaluation in awake infants and young children.

AIM: To evaluate dual-source high-pitch computed tomography (HPCT) imaging of the chest and abdomen as a rapid scanning technique to obtain diagnostic-quality imaging evaluation of infants and young children without sedation. MATERIALS AND METHODS: Fifty-three paediatric patients (age 24.1±2 months) who underwent chest or abdomen HPCT (≥1.5) and standard pitch CT (SPCT, <1.5) on a dual-source 128-row multidetector CT system were included in the study. Image quality assessment was performed by two paediatric radiologists for diagnostic confidence, image artefacts, and image noise. Objective image noise was measured. RESULTS: Most of the CT examinations were performed in children who were >1 year old (n=15 and n=20) followed by ≤1 year old (n=8 and n=10) in SPCT and HPCT, respectively. The mean radiation dose (SSDE) from HPCT was 1.96±1 mGy compared to 2.2±1 mGy for SPCT (p=0.3). No major artefacts were reported and overall image quality of all HPCT examinations was acceptable diagnostically. In addition, objective image noise values were not significantly different between HPCT compared with SPCT (11±3 versus 11±5, p=0.7). CONCLUSION: Ultra-fast, HPCT can be performed without the need for sedation as a potential alternative to anaesthetised magnetic resonance imaging in infants and young children.

Efficacy and safety of levetiracetam for migraine prophylaxis: A systematic review.

WHAT IS KNOWN AND OBJECTIVE: Migraine is a common and costly neurological disorder that affects approximately 1 of every 7 people annually. Pharmacological therapy for prevention of migraine is warranted when patients experience at least 6 headache days, 4 headache days with at least some impairment or 3 headache days with severe impairment or requiring bed rest in a month. Levetiracetam is an antiepileptic drug that has the potential to be beneficial for migraine prophylaxis. The objective of this review was to assess the safety and efficacy of levetiracetam for migraine prophylaxis. METHODS: A systematic search was conducted in MEDLINE (1946-August 2017), EMBASE (1947-August 2017) and CENTRAL using the terms: migraine disorders, migraine, or headache and etiracetam or levetiracetam. Animal studies, case reports, abstracts, letters to the editor and those not written in English were excluded. RESULTS AND DISCUSSION: Eleven articles were identified for inclusion. Of the studies included, 2 were retrospective chart reviews, 4 were randomized placebo- or active comparator-controlled trials, and the remaining 5 were prospective, open-label studies. All studies found a statistically significant decrease in headache frequency per month compared to baseline or placebo when used for treatment of episodic migraine (2.96-10.9 headache/mo decrease), and 57.9%-100% of patients had at least a 50% decrease in headache frequency from baseline. Significance was not consistently demonstrated in the prophylactic treatment of chronic migraine. The most common adverse effects noted included somnolence, dizziness and behavioural effects but generally did not require discontinuation. WHAT IS NEW AND CONCLUSION: The studies included in this review indicate that levetiracetam is well-tolerated and may be an alternative treatment option for episodic migraine prophylaxis. Additional clinical evidence is necessary to establish the efficacy of levetiracetam for the prophylactic treatment of chronic migraine.

Interaction of biomechanics with extracellular matrix components in abdominal aortic aneurysm wall.

OBJECTIVE: Little is known about the interactions between extracellular matrix (ECM) proteins and locally acting mechanical conditions and material macroscopic properties in abdominal aortic aneurysm (AAA). In this study, ECM components were investigated with correlation to corresponding biomechanical properties and loads in aneurysmal arterial wall tissue. METHODS: Fifty-four tissue samples from 31 AAA patients (30♂; max. diameter Dmax 5.98 ± 1.42 cm) were excised from the aneurysm sac. Samples were divided for corresponding immunohistological and mechanical analysis. Collagen I and III, total collagen, elastin, and proteoglycans were quantified by computational image analysis of histological staining. Pre-surgical CT data were used for 3D segmentation of the AAA and calculation of mechanical conditions by advanced finite element analysis. AAA wall stiffness and strength were assessed by repeated cyclical, sinusoidal and destructive tensile testing. RESULTS: Amounts of collagen I, III, and total collagen were increased with higher local wall stress (p = .002, .017, .030, respectively) and strain (p = .002, .012, .020, respectively). AAA wall failure tension exhibited a positive correlation with collagen I, total collagen, and proteoglycans (p = .037, .038, .022, respectively). α-Stiffness correlated with collagen I, III, and total collagen (p = .011, .038, and .008), while ß-stiffness correlated only with proteoglycans (p = .028). In contrast, increased thrombus thickness was associated with decreased collagen I, III, and total collagen (p = .003, .020, .015, respectively), and AAA diameter was negatively associated with elastin (p = .006). CONCLUSIONS: The present results indicate that in AAA, increased locally acting biomechanical conditions (stress and strain) involve increased synthesis of collagen and proteoglycans with increased failure tension. These findings confirm the presence of adaptive biological processes to maintain the mechanical stability of AAA wall.

Metrological challenges for reconstruction of 3-D microstructures by focused ion beam tomography methods.

The development of combined focused ion beam and scanning electron microscopes has enabled significant advances in the characterization of the 3-D structure of materials. The repeated removal of thin layers or slices with an ion beam and imaging or mapping the chemical or crystallographic structure of each slice enables a 3-D reconstruction from the images or maps. The accuracy of the reconstruction thus depends on the accuracy with which the slice thickness is measured and maintained throughout the process, and the alignment accuracy of the slices achieved during acquisition or by postacquisition corrections. A survey of papers published in this field suggests that the reconstruction accuracy is not often considered or reported. Using examples from examination of the 3-D structure of hardmetals, issues affecting the accuracy of slice thicknesses and image realignments are examined and illustrated and potential errors quantified by the use of fiducial markers and the expected isotropy of the hardmetal structure itself.

Lecanemab Clarity AD: Quality-of-Life Results from a Randomized, Double-Blind Phase 3 Trial in Early Alzheimer's Disease.

BACKGROUND: Lecanemab is a humanized IgG1 monoclonal antibody binding with high affinity to amyloid-beta protein protofibrils. In phase 3 development, lecanemab has been shown to reduce markers of amyloid in early Alzheimer's disease and reduce decline on clinical endpoints of cognition and function at 18 months. OBJECTIVES: To describe the health-related quality-of-life (HRQoL) results from Clarity AD which were exploratory outcomes in this trial. DESIGN: Clarity AD was an 18-month, multi-center, double-blind, phase 3 trial. SETTING: Early Alzheimer's disease. PARTICIPANTS: Individuals 50-90 years of age with a diagnosis of mild cognitive impairment or mild dementia due to Alzheimer's disease and positron emission tomography or cerebrospinal fluid evidence of cerebral amyloid accumulation. INTERVENTION: Placebo or lecanemab 10-mg/kg IV biweekly. MEASUREMENTS: HRQoL was measured at baseline and every 6 months using the European Quality of Life-5 Dimensions (EQ-5D-5L; by subject) and Quality of Life in AD (QOL-AD; by subject and proxy). Study partner burden was measured using the Zarit Burden Interview (ZBI). RESULTS: A total of 1795 participants were enrolled (lecanemab:898; placebo:897). At month 18, adjusted mean change from baseline in EQ-5D-5L and QOL-AD by subject showed 49% and 56% less decline, respectively. QOL-AD rated by study partner as proxy resulted in 23% less decline. ZBI adjusted mean change from baseline at 18 months resulted in 38% less increase of care partner burden. Individual HRQoL test items and dimensions also showed lecanemab benefit. CONCLUSIONS: Lecanemab was associated with a relative preservation of HRQoL and less increase in caregiver burden, with consistent benefits seen across different quality of life scales and within scale subdomains. These benefits provide valuable patient reported outcomes which, together with previously reported benefits of lecanemab across multiple measures of cognition, function, disease progression, and biomarkers, demonstrate that lecanemab treatment may offer meaningful benefits to patients, care partners, and society.

Diffusion tensor imaging of white matter tract evolution over the lifespan.

Diffusion tensor imaging (DTI) has been used widely to show structural brain changes during both development and aging. Lifespan studies are valuable because they connect these two processes, yet few DTI studies have been conducted that include both children and elderly subjects. This study used DTI tractography to investigate 12 major white matter connections in 403 healthy subjects aged 5-83 years. Poisson fits were used to model changes of fractional anisotropy (FA) and mean diffusivity (MD) across the age span, and were highly significant for all tracts. FA increased during childhood and adolescence, reached a peak between 20 and 42 years of age, and then decreased. MD showed an opposite trend, decreasing first, reaching a minimum at 18-41 years, and then increasing later in life. These trajectories demonstrate rates and timing of development and degradation that vary regionally in the brain. The corpus callosum and fornix showed early reversals of development trends, while frontal-temporal connections (cingulum, uncinate, superior longitudinal) showed more prolonged maturation and delayed declines. FA changes were driven by perpendicular diffusivity, suggesting changes of myelination and/or axonal density. Tract volume changed significantly with age for most tracts, but did not greatly influence the FA and MD trajectories. This study demonstrates clear age-related microstructural changes throughout the brain white matter, and provides normative data that will be useful for studying white matter development in a variety of diseases and abnormal conditions.

Perampanel Study 207: long-term open-label evaluation in patients with epilepsy.

OBJECTIVES: Evaluate interim long-term tolerability, safety and efficacy of adjunctive perampanel, a novel α-amino-3-hydroxy-5-methyl-5-isoxazolepropionic acid (AMPA)-receptor antagonist, in patients with refractory partial-onset seizures. MATERIALS AND METHODS: Study 207, an open-label extension (OLE) study (ClinicalTrials.gov identifier: NCT00368472), enrolled patients (18-70 years) who completed one of two randomized, placebo-controlled, dose-escalation Phase II studies. The OLE Treatment Phase comprised a 12-week Titration Period (2 mg increments of perampanel every 2 weeks to 12 mg/day, maximum) and a Maintenance Period, during which patients continued treatment up to a planned maximum of 424 weeks (~8 years). Interim analysis data cut-off date was 1 December, 2010. RESULTS: Of 180 patients completing the Phase II studies, 138 enrolled in study 207. At the time of interim analyses (approximately 4 years after study start), over a third (n = 53, 38.4%) remained on perampanel; 41.3% (n = 57) of patients had >3 years of exposure; and 13.0% (n = 18) had at least 4 years' exposure. Mean ± standard deviation (SD) duration of exposure was 116 ± 75 weeks and mean ± SD dose during the OLE Maintenance Period was 7.3 ± 3.3 mg. No new safety signals emerged with long-term treatment. Consistent with previous studies, the most common treatment-emergent adverse events were as follows: dizziness, headache and somnolence. Overall median (range) per cent change from baseline in seizure frequency per 28 days during open-label treatment was -31.5% (-99.2 to 512.2). CONCLUSIONS: Long-term - up to 4 years - adjunctive perampanel had a favourable tolerability profile in patients with refractory partial-onset seizures. Improvements in seizure control were maintained with long-term treatment.

Correction of artefacts associated with large area EBSD.

There is an increasing requirement for the acquisition of large two (2D) or three (3D) dimensional electron back scattered diffraction (EBSD) maps. It is a well-known, but largely neglected fact, that EBSD maps may contain distortions. These include long-range distortions, which can be caused by the interaction of the electron beam with the sample geometry and it can also arise from sample or beam drift. In addition there are shorter range artefacts arising from topographical features, such as curtaining. The geometrical distortions can be minimised by careful SEM calibrations and sample alignment. However, the long-range distortions become increasingly prevalent when acquiring large area 2D EBSD maps which take a long time to acquire and thus are especially prone to drift. These distortions are especially evident in serial section tomography (SST) when 2D maps are stacked on top of one another to produce 3D maps. Here we quantify these distortions for large area EBSD data by referencing them to secondary electron (SE) images for 3D-EBSD data acquired on a WCCo hardmetal. Long-range distortions (due to drift) equating to around 10µm across a 200µm x 175 µm area map, and short-range distortions (due to topographical effects) as large as 3 µm over a distance of 40 µm were observed. Methods for correcting these distortions are then proposed. This study illustrates the benefits and necessity of such corrections if morphological features are to be properly interpreted when collecting large 3D EBSD datasets, for example by mechanical sectioning, serial block face SEM ultramicrotomy, laser sectioning, FIB-SEM tomography, PFIB spin milling, etc.

Pediatric imaging: current and emerging techniques.

Imaging has always been an important component of the clinical evaluation of pediatric patients. Rapid technological advances in imaging are making noninvasive evaluation of a wide range of pediatric diseases possible. Ultrasound and magnetic resonance imaging (MRI) are two imaging modalities that do not involve ionizing radiation and are preferred imaging modalities in the pediatric population. Computed tomography (CT) remains the imaging modality with the highest increase in utilization in children due to its widespread availability and rapid image acquisition. Emerging imaging applications to be discussed include MR urography, voiding urosonography with use of ultrasound contrast agents, CT dose reduction techniques, MR enterography for inflammatory bowel disease, and MR cine airway imaging.

A comparison of methods for the isolation and separation of extracellular vesicles from protein and lipid particles in human serum.

Extracellular vesicles (EVs) are nano-sized vesicles containing nucleic acid and protein cargo that are released from a multitude of cell types and have gained significant interest as potential diagnostic biomarkers. Human serum is a rich source of readily accessible EVs; however, the separation of EVs from serum proteins and non-EV lipid particles represents a considerable challenge. In this study, we compared the most commonly used isolation techniques, either alone or in combination, for the isolation of EVs from 200 µl of human serum and their separation from non-EV protein and lipid particles present in serum. The size and yield of particles isolated by each method was determined by nanoparticle tracking analysis, with the variation in particle size distribution being used to determine the relative impact of lipoproteins and protein aggregates on the isolated EV population. Purification of EVs from soluble protein was determined by calculating the ratio of EV particle count to protein concentration. Finally, lipoprotein particles co-isolated with EVs was determined by Western blot analysis of lipoprotein markers APOB and APOE. Overall, this study reveals that the choice of EV isolation procedure significantly impacts EV yield from human serum, together with the presence of lipoprotein and protein contaminants.

Make room for dynein.

Three classes of cytoskeletal motor protein have been identified--myosins, kinesins and dyneins. Together, these proteins are now thought to be responsible for the remarkable variety of movements that occur in eukaryotic cells and that are essential for reproduction and survival. Crystallographic analysis of the myosin and kinesin motor domains at atomic resolution has provided insight into their mechanism of force production. However, because of its relative intractability to molecular manipulation, definition of the dynein motor domain, let alone progress in understanding how it works, has been slower. Evidence now indicates that the microtubule-binding domain of dynein is spatially isolated from the ATPase domain at the tip of a projecting coiled coil. As proposed here, this curious arrangement might serve to accommodate multiple copies of the outsized and functionally complex motor heads on the microtubule surface.

Eight-week, placebo-controlled, double-blind comparison of the antidepressant efficacy and tolerability of bupropion XR and venlafaxine XR.

The efficacy, safety and tolerability of bupropion XR and venlafaxine XR was assessed and compared with placebo in adult outpatients with major depressive disorder (MDD). Adults meeting DSM-IV criteria for MDD with a minimum Hamilton Depression Rating Scale (HAMD) 17-Item total score of > or =18 were randomized to eight weeks of double-blind treatment with either bupropion XR (150 mg/day), venlafaxine XR (75 mg/day) or placebo. At the end of the fourth week of treatment, a dosage increase to bupropion XR 300 mg/day or venlafaxine XR 150 mg/day was allowed if, in the opinion of the investigator, response was inadequate. The primary efficacy endpoint was mean change from baseline at week 8 in the Montgomery-Asberg Depression Rating Scale (MADRS) total score last observation carried forward (LOCF). Mean changes from baseline at week 8 (LOCF) in MADRS total score were statistically significant for bupropion XR and venlafaxine XR patients compared to the placebo group: -16.0 for bupropion XR (P = 0.006 vs placebo), -17.1 for venlafaxine XR (P < 0.001 vs placebo) and -13.5 for placebo. Secondary outcomes (including CGI-S, HAM-A, MEI, Q-LES-Q-SF, responder and remitter analyses) also improved significantly for both active treatment groups compared with placebo. The most frequently reported adverse events were dry mouth and insomnia for bupropion XR, and nausea, hyperhidrosis, fatigue, and insomnia for venlafaxine XR. In this double-blind, placebo-controlled trial, bupropion XR at doses up to 300 mg/day and venlafaxine XR at doses up to 150 mg/day demonstrated comparable antidepressant efficacy.

Practical application of direct electron detectors to EBSD mapping in 2D and 3D.

The use of a direct electron detector for the simple acquisition of 2D electron backscatter diffraction (EBSD) maps and 3D EBSD datasets with a static sample geometry has been demonstrated in a focused ion beam scanning electron microscope. The small size and flexible connection of the Medipix direct electron detector enabled the mounting of sample and detector on the same stage at the short working distance required for the FIB. Comparison of 3D EBSD datasets acquired by this means and with conventional phosphor based EBSD detectors requiring sample movement showed that the former method with a static sample gave improved slice registration. However, for this sample detector configuration, significant heating by the detector caused sample drift. This drift and ion beam reheating both necessitated the use of fiducial marks to maintain stability during data acquisition.

A multiphysics approach for modeling early atherosclerosis.

This work is devoted to the development of a mathematical model of the early stages of atherosclerosis incorporating processes of all time scales of the disease and to show their interactions. The cardiovascular mechanics is modeled by a fluid-structure interaction approach coupling a non-Newtonian fluid to a hyperelastic solid undergoing anisotropic growth and a change of its constitutive equation. Additionally, the transport of low-density lipoproteins and its penetration through the endothelium is considered by a coupled set of advection-diffusion-reaction equations. Thereby, the permeability of the endothelium is wall-shear stress modulated resulting in a locally varying accumulation of foam cells triggering a novel growth and remodeling formulation. The model is calibrated and applied to an murine-specific case study, and a qualitative validation of the computational results is performed. The model is utilized to further investigate the influence of the pulsatile blood flow and the compliance of the artery wall to the atherosclerotic process. The computational results imply that the pulsatile blood flow is crucial, whereas the compliance of the aorta has only a minor influence on atherosclerosis. Further, it is shown that the novel model is capable to produce a narrowing of the vessel lumen inducing an adaption of the endothelial permeability pattern.

Broad ion beam serial section tomography.

Here we examine the potential of serial Broad Ion Beam (BIB) Ar+ ion polishing as an advanced serial section tomography (SST) technique for destructive 3D material characterisation for collecting data from volumes with lateral dimensions significantly greater than 100µm and potentially over millimetre sized areas. Further, the associated low level of damage introduced makes BIB milling very well suited to 3D EBSD acquisition with very high indexing rates. Block face serial sectioning data registration schemes usually assume that the data comprises a series of parallel, planar slices. We quantify the variations in slice thickness and parallelity which can arise when using BIB systems comparing Gatan PECS and Ilion BIB systems for large volume serial sectioning and 3D-EBSD data acquisition. As a test case we obtain 3D morphologies and grain orientations for both phases of a WC-11%wt. Co hardmetal. In our case we have carried out the data acquisition through the manual transfer of the sample between SEM and BIB which is a very slow process (1-2 slice per day), however forthcoming automated procedures will markedly speed up the process. We show that irrespective of the sectioning method raw large area 2D-EBSD maps are affected by distortions and artefacts which affect 3D-EBSD such that quantitative analyses and visualisation can give misleading and erroneous results. Addressing and correcting these issues will offer real benefits when large area (millimetre sized) automated serial section BIBS is developed.

Adenovirus-mediated p53 gene therapy in osteosarcoma cell lines: sensitization to cisplatin and doxorubicin.

The poor prognosis for patients with metastatic osteosarcoma (OS) indicates that new therapeutic options should be explored. Studies with adenoviral-mediated p53 gene transfer have been conducted in many cancer types including cervical, ovarian, prostatic and head and neck tumors. However, limited work has been carried out with pediatric cancers, including OS. Using three viral constructs containing cDNA for wild-type p53, mutant p53 (Cys135Ser) and lacZ, we studied the effect of adenoviral-mediated gene therapy in four OS cell lines: Saos-2 (p53-/-), HOS (R156P), KHOS/NP (R156P) and MNNG (R156P, F270L). We demonstrated that the virus efficiently enters the cells using the beta-galactosidase assay. Using the MTT assay, we have shown a dose-dependent decrease in cell viability 72 h post-treatment that occurs with Ad-wtp53 but not with Ad-mutp53. We have also shown that treatment with Ad-wtp53 significantly increases sensitivity of the cell lines to cisplatin and doxorubicin, chemotherapeutic agents commonly used in the treatment of OS. Our results indicate that restoration of wt p53 function in OS cells provides a basis for novel approaches to treatment of this disease.

Nuclear catalyzed antibiotic free radical formation.

Nuclei isolated from rat liver, heart, and kidney catalyze oxygen consumption in the presence of reduced pyridine nucleotide (NADPH) and quinone or quinone-imine antibiotics such as Adriamycin, daunorubicin, actinomycin D, mitomycin C, and streptonigrin. The Km and Vmax values for NADPH were 2.4 x 10(-3) M and 3 x 10(-8) mol O2 per min per mg protein and Km values for the antibiotics ranged from 1.4 x 10(-4) M to 5.9 x 10(-6) M. Metabolism of the anthracycline antibiotics, i.e., reductive glycosidase reaction, occurs in reaction mixtures after all oxygen is consumed. During the reaction, free-radical species of Adriamycin and daunorubicin are detectable by electron paramagnetic reasonance spectrometry. These observations indicate that some cytotoxic antibiotics can be activated to a free-radical state at the site where damage to nuclear DNA may result.

Quantitative T1rho magnetic resonance imaging of RIF-1 tumors in vivo: detection of early response to cyclophosphamide therapy.

This study compares two potential magnetic resonance imaging (MRI) indices for noninvasive early detection of tumor response to chemotherapy: the spin-lattice relaxation in the rotating frame (T1rho) and the transverse relaxation time (T2). Measurements of these relaxation parameters were performed on a s.c. murine radiation-induced fibrosarcoma (RIF-1) model before and after cyclophosphamide treatment. The number of pixels exhibiting T1rho values longer than controls in viable regions of the tumor increased significantly as early as 18 h after drug administration and remained elevated up to 36 h after treatment (P < 0.005). Although a trend of increasing T2s relative to controls was noted in viable regions of the tumor 36 h after treatment, the changes were not statistically significant. Histological examination indicated a decrease in mitotic index that paralleled the changes in T1rho. We conclude that T1rho measurements may be useful for noninvasive monitoring of early response of tumors to chemotherapy.

Hypoxia-mediated apoptosis from angiogenesis inhibition underlies tumor control by recombinant interleukin 12.

The role of angiogenesis inhibition in the antitumor activity of recombinant murine interleukin 12 (rmIL-12) was studied in K1735 murine melanomas, the growth of which is rapidly and markedly suppressed by rmIL-12 treatment. On the basis of the prediction that tumor ischemia should result from therapeutic angiogenesis inhibition, tumor cell hypoxia was evaluated as a marker of ischemia using the EF5 [2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)aceta mide] approach. This method measures intracellular binding of the nitroimidazole EF5, which covalently binds to cellular macromolecules selectively under hypoxic conditions. Whereas 1 week of rmIL-12 treatment effectively inhibited K1735 cell-induced angiogenesis in Matrigel neovascularization assays, 2 weeks of treatment were needed before severe tumor cell hypoxia was detected in K1735 tumors. The hypoxia that developed was regional and localized to tumor areas distant from blood vessels. The great majority of severely hypoxic tumor cells were apoptotic, and in vitro studies indicated that the degree of hypoxia present within treated tumors was sufficient to trigger K1735 apoptosis. Tumor cell apoptosis was also prevalent in the first week of rmIL-12 treatment when few cells were hypoxic. In vitro studies indicated that this non-hypoxia-related apoptosis was induced directly by IFN-gamma produced in response to rmIL-12 administration. These studies reveal that rmIL-12 controls K1735 tumors initially by IFN-gamma-induced apoptosis and later by hypoxia-induced apoptosis. They also establish hypoxia as an expected result of tumor angiogenesis inhibition and a mediator of its therapeutic effect.