Energetic Electron Precipitation Driven by Electromagnetic Ion Cyclotron Waves from ELFIN's Low Altitude Perspective.

We review comprehensive observations of electromagnetic ion cyclotron (EMIC) wave-driven energetic electron precipitation using data collected by the energetic electron detector on the Electron Losses and Fields InvestigatioN (ELFIN) mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000 keV electrons with good pitch-angle and energy resolution. EMIC wave-driven precipitation exhibits a distinct signature in energy-spectrograms of the precipitating-to-trapped flux ratio: peaks at >0.5 MeV which are abrupt (bursty) (lasting ∼17 s, or ΔL∼0.56) with significant substructure (occasionally down to sub-second timescale). We attribute the bursty nature of the precipitation to the spatial extent and structuredness of the wave field at the equator. Multiple ELFIN passes over the same MLT sector allow us to study the spatial and temporal evolution of the EMIC wave - electron interaction region. Case studies employing conjugate ground-based or equatorial observations of the EMIC waves reveal that the energy of moderate and strong precipitation at ELFIN approximately agrees with theoretical expectations for cyclotron resonant interactions in a cold plasma. Using multiple years of ELFIN data uniformly distributed in local time, we assemble a statistical database of ∼50 events of strong EMIC wave-driven precipitation. Most reside at L∼5-7 at dusk, while a smaller subset exists at L∼8-12 at post-midnight. The energies of the peak-precipitation ratio and of the half-peak precipitation ratio (our proxy for the minimum resonance energy) exhibit an L-shell dependence in good agreement with theoretical estimates based on prior statistical observations of EMIC wave power spectra. The precipitation ratio's spectral shape for the most intense events has an exponential falloff away from the peak (i.e., on either side of ∼1.45 MeV). It too agrees well with quasi-linear diffusion theory based on prior statistics of wave spectra. It should be noted though that this diffusive treatment likely includes effects from nonlinear resonant interactions (especially at high energies) and nonresonant effects from sharp wave packet edges (at low energies). Sub-MeV electron precipitation observed concurrently with strong EMIC wave-driven >1 MeV precipitation has a spectral shape that is consistent with efficient pitch-angle scattering down to ∼ 200-300 keV by much less intense higher frequency EMIC waves at dusk (where such waves are most frequent). At ∼100 keV, whistler-mode chorus may be implicated in concurrent precipitation. These results confirm the critical role of EMIC waves in driving relativistic electron losses. Nonlinear effects may abound and require further investigation.

Guidelines To Validate Control of Cross-Contamination during Washing of Fresh-Cut Leafy Vegetables.

The U.S. Food and Drug Administration requires food processors to implement and validate processes that will result in significantly minimizing or preventing the occurrence of hazards that are reasonably foreseeable in food production. During production of fresh-cut leafy vegetables, microbial contamination that may be present on the product can spread throughout the production batch when the product is washed, thus increasing the risk of illnesses. The use of antimicrobials in the wash water is a critical step in preventing such water-mediated cross-contamination; however, many factors can affect antimicrobial efficacy in the production of fresh-cut leafy vegetables, and the procedures for validating this key preventive control have not been articulated. Producers may consider three options for validating antimicrobial washing as a preventive control for cross-contamination. Option 1 involves the use of a surrogate for the microbial hazard and the demonstration that cross-contamination is prevented by the antimicrobial wash. Option 2 involves the use of antimicrobial sensors and the demonstration that a critical antimicrobial level is maintained during worst-case operating conditions. Option 3 validates the placement of the sensors in the processing equipment with the demonstration that a critical antimicrobial level is maintained at all locations, regardless of operating conditions. These validation options developed for fresh-cut leafy vegetables may serve as examples for validating processes that prevent cross-contamination during washing of other fresh produce commodities.

Field dipolarization in Saturn's magnetotail with planetward ion flows and energetic particle flow bursts: Evidence of quasi-steady reconnection.

We present a case study of an event from 20 August (day 232) of 2006, when the Cassini spacecraft was sampling the region near 32 RS and 22 h LT in Saturn's magnetotail. Cassini observed a strong northward-to-southward turning of the magnetic field, which is interpreted as the signature of dipolarization of the field as seen by the spacecraft planetward of the reconnection X line. This event was accompanied by very rapid (up to ~1500 km s-1) thermal plasma flow toward the planet. At energies above 28 keV, energetic hydrogen and oxygen ion flow bursts were observed to stream planetward from a reconnection site downtail of the spacecraft. Meanwhile, a strong field-aligned beam of energetic hydrogen was also observed to stream tailward, likely from an ionospheric source. Saturn kilometric radiation emissions were stimulated shortly after the observation of the dipolarization. We discuss the field, plasma, energetic particle, and radio observations in the context of the impact this reconnection event had on global magnetospheric dynamics.

Surface current balance and thermoelectric whistler wings at airless astrophysical bodies: Cassini at Rhea.

Sharp magnetic perturbations found by the Cassini spacecraft at the edge of the Rhea flux tube are consistent with field-aligned flux tube currents. The current system results from the difference of ion and electron gyroradii and the requirement to balance currents on the sharp Rhea surface. Differential-type hybrid codes that solve for ion velocity and magnetic field have an intrinsic difficulty modeling the plasma absorber's sharp surface. We overcome this problem by instead using integral equations to solve for ion and electron currents and obtain agreement with the magnetic perturbations at Rhea's flux tube edge. An analysis of the plasma dispersion relations and Cassini data reveals that field-guided whistler waves initiated by (1) the electron velocity anisotropy in the flux tube and (2) interaction with surface sheath electrostatic waves on topographic scales may facilitate propagation of the current system to large distances from Rhea. Current systems like those at Rhea should occur generally, for plasma absorbers of any size such as spacecraft or planetary bodies, in a wide range of space plasma environments. Motion through the plasma is not essential since the current system is thermodynamic in origin, excited by heat flow into the object. The requirements are a difference of ion and electron gyroradii and a sharp surface, i.e., without a significant thick atmosphere. KEY POINTS: Surface current balance condition yields a current system at astronomical bodiesCurrent system possible for sharp (airless) objects of any sizeCurrent system is thermoelectric and motion through the plasma nonessential.

Detection of a strongly negative surface potential at Saturn's moon Hyperion.

On 26 September 2005, Cassini conducted its only close targeted flyby of Saturn's small, irregularly shaped moon Hyperion. Approximately 6 min before the closest approach, the electron spectrometer (ELS), part of the Cassini Plasma Spectrometer (CAPS) detected a field-aligned electron population originating from the direction of the moon's surface. Plasma wave activity detected by the Radio and Plasma Wave instrument suggests electron beam activity. A dropout in energetic electrons was observed by both CAPS-ELS and the Magnetospheric Imaging Instrument Low-Energy Magnetospheric Measurement System, indicating that the moon and the spacecraft were magnetically connected when the field-aligned electron population was observed. We show that this constitutes a remote detection of a strongly negative (∼ -200 V) surface potential on Hyperion, consistent with the predicted surface potential in regions near the solar terminator.

Intraoperative management of renal allograft venous-calyceal fistula and incidental renal cell carcinoma during renal transplantation: a case report.

This case report describes rare intraoperative complications during renal allotransplantation. A 59-year-old man underwent an expanded criteria deceased donor renal transplantation. A wedge biopsy, as per institution protocol, was performed prior to surgery. After vascular anastomoses, the kidney was reperfused; immediate significant hematuria was noted from the ureter. After exploration, compression of the wedge biopsy site stopped the bleeding, suggesting a venous-calyceal fistula. An incision at the wedge biopsy site was made to do an open repair, yielding a small suspicious lesion. Frozen section confirmed clear cell renal carcinoma, which was completely resected. The hematuria resolved after renorrhaphy, and we proceeded with ureteral reimplantation. Postoperatively, the patient was maintained on immunosuppression, free of recurrence at eight months. The surgeon must be aware of the possibilities of unusual complications as well as treatment options. This study provides a treatment strategy to address these challenging intraoperative complications.

Nanomechanical sensing of the endothelial cell response to anti-inflammatory action of 1-methylnicotinamide chloride.

BACKGROUND: There is increasing evidence that cell elastic properties should change considerably in response to chemical agents affecting the physiological state of the endothelium. In this work, a novel assay for testing prospective endothelium-targeted agents in vitro is presented. MATERIALS AND METHODS: The proposed methodology is based on nanoindentation spectroscopy using an atomic force microscope tip, which allows for quantitative evaluation of cell stiffness. As an example, we chose a pyridine derivative, 1-methylnicotinamide chloride (MNA), known to have antithrombotic and anti-inflammatory properties, as reported in recent in vivo experiments. RESULTS: First, we determined a concentration range of MNA in which physiological parameters of the endothelial cells in vitro are not affected. Then, cell dysfunction was induced by incubation with tumor necrosis factor-alpha (TNF-α) and the cellular response to MNA treatment after TNF-α incubation was studied. In parallel to the nanoindentation spectroscopy, the endothelium phenotype was characterized using a fluorescence spectroscopy with F-actin labeling, and biochemical methods, such as secretion measurements of both nitric oxide (NO), and prostacyclin (PGI2) regulatory agents. CONCLUSION: We found that MNA could reverse the dysfunction of the endothelium caused by inflammation, if applied in the proper time and to the concentration scheme established in our investigations. A surprisingly close correlation was found between effective Young's modulus of the cells and actin polymerization/depolymerization processes in the endothelium cortical cytoskeleton, as well as NO and PGI2 levels. These results allow us to construct the physiological model of sequential intracellular pathways activated in the endothelium by MNA.

The dust halo of Saturn's largest icy moon, Rhea.

Saturn's moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally affecting Saturn's magnetosphere. The Cassini spacecraft's in situ observations reveal that energetic electrons are depleted in the moon's vicinity. The absence of a substantial exosphere implies that Rhea's magnetospheric interaction region, rather than being exclusively induced by sputtered gas and its products, likely contains solid material that can absorb magnetospheric particles. Combined observations from several instruments suggest that this material is in the form of grains and boulders up to several decimetres in size and orbits Rhea as an equatorial debris disk. Within this disk may reside denser, discrete rings or arcs of material.

Identification of a dynamic atmosphere at Enceladus with the Cassini magnetometer.

The Cassini magnetometer has detected the interaction of the magnetospheric plasma of Saturn with an atmospheric plume at the icy moon Enceladus. This unanticipated finding, made on a distant flyby, was subsequently confirmed during two follow-on flybys, one very close to Enceladus. The magnetometer data are consistent with local outgassing activity via a plume from the surface of the moon near its south pole, as confirmed by other Cassini instruments.

Anti-planetward auroral electron beams at Saturn.

Strong discrete aurorae on Earth are excited by electrons, which are accelerated along magnetic field lines towards the planet. Surprisingly, electrons accelerated in the opposite direction have been recently observed. The mechanisms and significance of this anti-earthward acceleration are highly uncertain because only earthward acceleration was traditionally considered, and observations remain limited. It is also unclear whether upward acceleration of the electrons is a necessary part of the auroral process or simply a special feature of Earth's complex space environment. Here we report anti-planetward acceleration of electron beams in Saturn's magnetosphere along field lines that statistically map into regions of aurora. The energy spectrum of these beams is qualitatively similar to the ones observed at Earth, and the energy fluxes in the observed beams are comparable with the energies required to excite Saturn's aurora. These beams, along with the observations at Earth and the barely understood electron beams in Jupiter's magnetosphere, demonstrate that anti-planetward acceleration is a universal feature of aurorae. The energy contained in the beams shows that upward acceleration is an essential part of the overall auroral process.

Cassini magnetometer observations during Saturn orbit insertion.

Cassini's successful orbit insertion has provided the first examination of Saturn's magnetosphere in 23 years, revealing a dynamic plasma and magnetic environment on short and long time scales. There has been no noticeable change in the internal magnetic field, either in its strength or its near-alignment with the rotation axis. However, the external magnetic field is different compared with past spacecraft observations. The current sheet within the magnetosphere is thinner and more extended, and we observed small diamagnetic cavities and ion cyclotron waves of types that were not reported before.

Aspiration cytology of pediatric solitary papillary hyperplastic thyroid nodule.

CONTEXT: Solitary papillary hyperplastic thyroid nodules (SPHTNs) are frequently encountered in children and teenagers. Although the histologic features are well described, to the best of our knowledge, cytologic findings have not been reported. OBJECTIVES: To review the cytologic features of histologically proven SPHTNs and to identify the potential diagnostic pitfalls in cytologic diagnosis. MATERIALS AND METHODS: Fine-needle aspiration cytology of 3 histologically proven SPHTNs was reviewed. RESULTS: Two girls and 1 boy (ages 11, 12, and 15 years) were affected. The cytologic diagnosis in all 3 cases was suspicious for papillary thyroid carcinoma (PTC). The spectrum of cytologic findings included broad flat sheets and 3-dimensional clusters with fire flares. There was mild to moderate nuclear pleomorphism and nuclear atypia. Short nonbranching papillae with transgressing vessels shown to represent hyperplastic papillae on histologic sections were identified in all cases. The background contained giant cells, histiocytes, and watery and inspissated colloid. Although nuclear grooves were identified in occasional cells, intranuclear inclusions were absent. A cell block section (1 case) and histologic sections of SPHTNs (2 cases) were immunohistochemically negative for cytokeratin 19. CONCLUSIONS: Fine-needle aspiration of SPHTNs may be difficult to interpret accurately and can result in false-positive diagnosis of PTC. Although it shares several cytologic features with PTC, the presence of fire flares and short nonbranching papillae, as well as lack of intranuclear inclusions and watery and inspissated colloid in SPHTN appear to be useful features that are helpful in distinguishing SPHTN from PTC. Negative immunohistochemical staining for cytokeratin 19 is useful in excluding a diagnosis of PTC.

Diagnosing primary and metastatic renal cell carcinoma: the use of the monoclonal antibody 'Renal Cell Carcinoma Marker'.

The diagnosis of primary or metastatic renal cell carcinoma (RCC) can be difficult, especially in small biopsies, because of the wide variety of histologic appearances and clinical presentations that RCC can assume. An immunomarker specific for RCC is currently not available. We tested the relevant diagnostic use of the Renal Cell Carcinoma Marker (RCC Ma), a monoclonal antibody, against a normal human proximal tubular brush border antigen. Immunostaining using RCC Ma and the avidin-biotin-peroxidase complex technique was performed on archival tissues from primary and metastatic tumors of renal or nonrenal origin. A total of 122 of 153 primary RCCs (79.7%) were positive [clear cell (84%), papillary (96%), chromophobe (45%), sarcomatoid (25%), and collecting duct (0%)], with > or =10% of tumor cells stained in 93% of cases. None of the 64 primary renal tumors other than RCC, including 15 oncocytomas, was positive. Fifteen of 146 (10.2%) nonrenal primary tumors were positive (5 of 17 breast tumors, 8 of 8 parathyroid adenomas, and 2 of 7 embryonal carcinomas). Forty-two of 63 (67%) metastatic RCCs were positive with > or =10% of cells being stained in 83% of them. Two of 108 (2%) metastases from tumors other than RCCs were positive, both of which were metastatic breast carcinomas; however, only 10% (2 of 19) of metastatic breast carcinomas were positive. RCC Ma is an excellent marker for primary RCC, which should facilitate its diagnosis in a small biopsy. Although RCC Ma remains highly specific (98%) for metastatic RCC, a negative result may not rule out metastatic RCC because of a rather low sensitivity and a focal staining pattern in some of the positive cases. RCC Ma may also facilitate the differential diagnosis between oncocytoma and other types of RCC when they are composed mostly of eosinophilic cells.

The role of fine-needle aspiration biopsy in the diagnosis and management of juvenile hemangioma of the parotid gland and cheek.

BACKGROUND: The current recommendation for the management of juvenile hemangiomas (JH) is to delay treatment in the hope of spontaneous regression. However, accurate diagnosis is necessary before considering conservative management. Traditionally, the diagnosis of JH has required excisional biopsy. The cytology literature on this relatively rare neoplasm is sparse. OBJECTIVE: To present our experience with fine-needle aspiration in the diagnosis and management of JH. DESIGN: Three cases with a cytologic diagnosis consistent with JH of the parotid gland and cheek were identified from our cytopathology files. Aspirate smears, immunohistochemical studies, computed tomographic scan findings, and clinical follow-up were reviewed. RESULTS: Patients were female infants ranging in age from 3 to 9 months and presented with an oval firm mass (size range, 2.0-5.0 cm) involving the parotid gland (2 cases) and cheek (1 case). Computed tomographic scan with contrast demonstrated homogeneous enhancement. Aspirate smears revealed spindle-shaped cells in sheets and clusters in a background of blood. The parotid gland aspirates and cell block preparations revealed ductal structures entrapped in sheets of spindle-shaped cells. Immunohistochemical studies revealed prominent vascular spaces lined by CD34 and factor VIII-positive flattened endothelial cells. The diagnosis of JH was rendered on the basis of the cytologic findings in conjunction with the radiologic and clinical findings. On clinical follow-up (8-24 months), none of the patients has shown any progression of the lesion. CONCLUSIONS: Fine-needle aspiration, in conjunction with imaging studies, is a useful tool in the diagnosis and management of JH. It eliminates the need for surgical excision for diagnostic purposes and allows for clinical follow-up of patients with JH.

Diagnostic utility of intracytoplasmic lumen and transgressing vessels in evaluation of Hürthle cell lesions by fine-needle aspiration.

INTRODUCTION: Recent abstracts have emphasized the importance of recognizing intracytoplasmic lumen and transgressing vessels as useful criteria enabling distinction between Hürthle cells encountered in neoplastic and nonneoplastic thyroid aspirates. The purpose of this retrospective study was to evaluate if application of these criteria improves specificity and sensitivity of cytologic diagnosis of true Hürthle cell neoplasms. MATERIALS AND METHODS: We retrospectively reviewed 30 fine-needle aspirates of thyroid with cytologic diagnosis of Hürthle cell neoplasms (13 cases) and nonneoplastic thyroid with prominent Hürthle cells (17 cases). All cases were evaluated for the presence of intracytoplasmic lumen and transgressing vessels and were reclassified as neoplastic or nonneoplastic based on the presence or absence of 1 or both of these criteria. Surgical follow-up was available in all cases. RESULTS: Surgical follow-up in 13 cases of Hürthle cell neoplasms revealed Hürthle cell carcinoma (3 cases), Hürthle cell adenoma (6 cases), and Hashimoto's thyroiditis (4 cases). Seventeen cases with nonneoplastic diagnosis revealed Hürthle cell carcinoma (1 case), Hashimoto's thyroiditis (12 cases), and nodular goiter (4 cases). After application of the previously mentioned cytologic criteria, the cytologic diagnoses were reclassified as Hürthle cell neoplasms (13 cases) and nonneoplastic thyroid (17 cases). The true sensitivity of the test before and after the application of the criteria was 90% and 100%, respectively. The true specificity before and after the application of the cytologic criteria was 65% and 85%, respectively. CONCLUSIONS: Intracytoplasmic lumen and transgressing vessels are helpful features in distinguishing neoplastic and nonneoplastic Hürthle cell thyroid lesions. Use of these criteria may improve the specificity and sensitivity of the cytologic diagnosis.

Oestrogen receptor expression in normal breast epithelium.

Higher levels of oestrogen receptor (ER) expression in normal breast epithelium may compound the increase in breast cancer risk seen with prolonged estrogen exposure. In prior studies, we have used immunohistochemical ER assays on fresh frozen samples of benign breast tissue. Future studies will be more feasible on paraffin-embedded samples, and newer, more sensitive antibodies are now available. We examined 30 samples of paraffin-embedded breast epithelium from postmenopausal women with two antibodies, 6F11 and TE111. We find that the median labelling indices for ER are significantly higher using these antibodies, compared with previous results. The threshold for ER positivity will, therefore, have to be reset in future studies, since there are still many issues that remain to be resolved in this area.

Galileo magnetometer measurements: a stronger case for a subsurface ocean at Europa.

On 3 January 2000, the Galileo spacecraft passed close to Europa when it was located far south of Jupiter's magnetic equator in a region where the radial component of the magnetospheric magnetic field points inward toward Jupiter. This pass with a previously unexamined orientation of the external forcing field distinguished between an induced and a permanent magnetic dipole moment model of Europa's internal field. The Galileo magnetometer measured changes in the magnetic field predicted if a current-carrying outer shell, such as a planet-scale liquid ocean, is present beneath the icy surface. The evidence that Europa's field varies temporally strengthens the argument that a liquid ocean exists beneath the present-day surface.

Is repeated fine-needle aspiration cytology useful in the management of patients with benign nodular thyroid disease?

Management of nonneoplastic thyroid nodules (TN) diagnosed by fine-needle aspiration (FNA) is controversial. While clinical follow-up with repeat FNA for enlarging TN is recommended in some studies, others recommend repeat FNA in follow-up of all benign TN after several months or years, in order to identify possible misdiagnosed malignant lesions. This study was done to determine the usefulness of repeat FNA in patients with benign nodular thyroid disease. We studied 94 fine-needle reaspirations performed on 43 females and 2 males 48.2 +/- 17 years of age with benign nodular thyroid nodular disease. Four patients had 3 consecutive FNAs and 41 patients had 2 consecutive FNAs. All FNAs were carried out by the same endocrinologist in the same thyroid area or by cytopathologists. The average time elapsed between the two consecutive FNAs was 18.3 +/- 11.2 (range, 4-48) months. Of the 45 patients, 23 presented with increase in size of the nodule and the remaining 22 patients did not have any change in size at the time of repeat FNA. Identical cytologic diagnoses were rendered in 39 of the 45 patients who underwent 2 or 3 consecutive FNA. Repeat FNA did not result in detection of any malignant neoplasms. Thyroid resection in 7 patients with increased nodule size and pressure symptoms confirmed the cytologic impressions of benign thyroid nodular disease. Our results show that the routine performance of repeated FNA cytology in the follow-up of patients with benign nodular thyroid disease with or without any clinical changes is of limited usefulness. Clinical factors rather than repeat FNA may hold precedence in surgical management of patients with benign nodular thyroid disease.

The clinical application and cost analysis of fine-needle aspiration biopsy in the diagnosis of mass lesions in sarcoidosis.

BACKGROUND: Sarcoidosis is a prevalent disease of unknown cause characterized by granulomatous inflammation that often creates deep and/or superficial mass lesions. Tissue samples are considered the "gold standard" in diagnosis; however, it is a medically treated disease. We analyzed the utility and relative cost-effectiveness of fine-needle aspiration biopsy (FNAB) in the clinical investigation of patients with both suspected and unsuspected sarcoidosis. METHODS: All FNAB cases with sarcoidosis either as the cytologic diagnosis or mentioned as part of the differential diagnosis were retrospectively reviewed for clinical history, follow-up, cytologic features, and surgical pathology findings. Comparative analysis of cost of FNAB and excisional biopsy were also made. RESULTS: Thirty-two FNABs in 28 patients included 17 women and 11 men. Anatomic sites included lymph node (n = 17), lung (n = 5), salivary gland (n = 8), and liver (n = 2). Sarcoidosis had already been diagnosed or was a clinical consideration prior to FNAB in 14 cases. Chest radiograph showed abnormal findings in 19 cases. Angiotensin-converting enzyme (ACE) was measured in seven patients and was elevated in four. All aspirates showed granulomatous inflammation; in 22 patients, special stains or cultures for microorganisms were negative. Simultaneous or subsequent excisional biopsies confirmed the FNAB findings in 17 patients. Institutional ratios of excisional biopsy to FNAB in the diagnosis of sarcoidosis ranged from 4 to 19:1. The cost of FNAB was only 12.5 to 50% that of tissue biopsy. CONCLUSIONS: FNAB appears to be underutilized in the diagnosis of sarcoidosis. When used in conjunction with radiologic and laboratory data, FNAB may be a reliable and cost-effective method of diagnosis, especially in patients with an established diagnosis of sarcoidosis.

Isolation and characterization of human breast adenocarcinoma cells made resistant to alpha-difluoromethylornithine.

Human breast adenocarcinoma cells MCF-7 were selected for resistance to ornithine decarboxylase (ODC) inhibitor, alpha-difluoromethylornithine (DFMO). Stepwise increments of the concentration of DFMO resulted in selection of MCF-7 cells that were capable of growing in the presence of 1.0 mM DFMO. This capacity was associated with a 10-fold increase in ODC activity and marked enhancement in the synthesis rate of ODC protein as verified by a 2-hr [35S]methionine labeling of cellular proteins followed by immunoprecipitation and SDS-PAGE. The resistant cells had much higher concentration of putrescine, spermidine, and spermine than the control cells. A 25-fold increase in ED50 (effective dose causing 50% inhibition) for the antiproliferative action of DFMO in these resistant cells was observed. The susceptibility of wild-type and resistant cell lines to other inhibitors of the polyamine biosynthetic pathway and adriamycin is also reported.