Comparison of two ultrasound contrast agents for left ventricular opacification

Funding Acknowledgements

Type of funding sources: None.

Background

Several ultrasound contrast agents have been approved and used for measurement of LV volumes and ejection fraction (EF). However, there has been no direct comparison between these agents.

Purpose

To compare different imaging parameters between two widely used ultrasound contrast agents for LV opacification when imaged with a low power contrast specific imaging modality

Methods

A retrospective study was performed using recordings of the local echocardiography registry for patients undergoing chemotherapy for cancer treatment.  Patients were included who underwent follow-up echocardiograms (3 months) with 2 different ultrasound contrast agents and had only minor changes in the LV ejection fraction (EF) between the studies (<5%). Qualitative and quantitative analysis of the contrast effect was performed in apical four- and two chamber views (4CV,2CV). For quantitative analysis of the LV opacification square regions of interest (ROI) were placed in the apical and basal regions of the ventricle in each echocardiographic recording and the arithmetic mean and standard deviation of pixel intensity within each ROI was recorded throughout the entire loop. Qualitative visual assessment was performed using a three step visual score in order to assess the endocardial border delineation, basal attenuation and apical swirling. Wilcoxon signed-rank test was used to compare the measurements obtained with different contrast agents.

Results

41 patients fulfilled the inclusion criteria. In all patients suitable recordings for measurement of LV volumes and EF were obtained. The mean + standard deviation of the EF was 61 + 9%. Both contrast agents provided intensive LV opacification in the basal and apical cavities. The video intensities (mean + standard deviation) in the apical and basal cavities were comparable across both contrast agents in the 2CV apical ROI (219.96 + 21.42 vs 224.69 + 20.23, p = 0.32), the 2CV basal ROI (114.55, 42.02 vs 112.79, 42.57, p = 0.81), the 4CV apical ROI (228.02, 17.80 vs 225.51, 20.37, p = 0.30), and the 4CV basal ROI (100.05, 41.11 vs 92.84, 42.54, p = 0.37). Visual assessment of endocardial delineation on end-diastolic and end-systolic frames revealed no statistical difference between the contrast agents.

Conclusion

In patients with normal LV function no clinically relevant differences were found between the two contrast agents regarding LV opacification and endocardial border delineation.

Abstract P1-03-07: Breast cancer diagnosis is associated with relative left ventricular hypertrophy

Background: Cardiac dysfunction is a major concern for patients with breast cancer (BC) receiving adjuvant therapy. Retrospective, cross-sectional echocardiographic data suggests that patients with cancer have reduced myocardial strain prior to cancer therapy exposure. Cardiac magnetic resonance (CMR) is the gold standard imaging modality for cardiac structure and function and can also evaluate myocardial micro-architecture with T1 mapping. We hypothesized that treatment naïve patients with early-stage BC (ESBC) have abnormal myocardial tissue characteristics on CMR.

Methods: Women with newly diagnosed ESBC were prospectively recruited for CMR prior to cancer drug treatment. Those with hypertension, diabetes mellitus or prior cancer treatments were excluded. Age and sex matched healthy controls were identified from a prior prospective study. All participants underwent a non-contrast CMR scan on a 1.5T magnet. Image acquisition included cines for cardiac structure and function as well as T1 mapping using saturation recovery single-shot acquisitions. Global longitudinal strain (GLS) was derived from cine images. Demographics and imaging metrics for healthy controls and patients were compared using two-sample t-test.

Results: 106 patients with ESBC, mean age 51±9, were included along with 55 matched healthy controls. Body mass index and systolic blood pressure were similar between groups, however resting heart rate was elevated in patients compared to controls, 77±11 vs 67±11 /min respectively, p<0.001 (Table 1). On CMR there was no difference in left ventricular volume or ejection fraction however global longitudinal strain was higher in patients compared to controls, -20.9±2.3 vs -19.9±3.7%, p=0.04 (Table 2). Left ventricular mass was higher compared to controls, 52±6 and 47±6 g/m2 respectively, p<0.001. However myocardial T1 was similar between groups, T1=1198±27ms for controls vs 1206±46ms for patients, p=0.42.

Conclusions: The cardiac phenotype of patients with ESBC is characterized by relative left ventricular hypertrophy with normal myocardial tissue. Further understanding of the mechanisms involved may provide insight into the cardiovascular risk associated with BC diagnosis.

Table 1.Demographics Healthy Controls (n=55)Breast Cancer (n=106)P valueAge, years (SD)52(14)51(9)0.49Body mass index, kg/m2 (SD)26(5)27(6)0.38Hypertension, number00NADiabetes Mellitus, number00NAReceptor status, number (%)  NAER/PRNA92(87%) HER2NA74(70%) Triple negativeNA2(2%) Stage, number (%)  NA1NA43(42%) 2NA41(38%) 3NA23(20%) Systolic blood pressure, mmHg (SD)127(15)124(13)0.19Heart rate, /min (SD)67(11)77(11)<0.001SD=standard deviation, NA=not applicable

Table 2.Cardiac Magnetic Resonance Healthy Controls (n=55)Breast Cancer (n=106)P valueLVEF, % (SD)62(4)62(5)0.91Indexed LVEDV, ml/m2 (SD)69(9)72(14)0.18Indexed LV mass, g/m2 (SD)47(6)52(6)<0.001LV mass/LVEDV (SD)0.69(0.08)0.74(0.13)0.002Indexed left atrial volume, ml/m2 (SD)40(9)37(10)0.21Global longitudinal strain, % (SD)-19.9(3.7)-20.9(2.3)0.04Myocardial T1, ms (SD)1198(27)1206(46)0.42SD=standard deviation, LVEF=left ventricular ejection fraction, LVEDV=left ventricular end-diastolic volume, LV=left ventricular

Citation Format: Kirkham A, Xu L, Wang H, Chow K, Pagano JJ, White J, Haykowsky MJ, Dyck JR, Ezekowitz JA, Oudit GY, Mackey JR, Thompson RB, Pituskin E, Paterson I. Breast cancer diagnosis is associated with relative left ventricular hypertrophy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-03-07.

Abstract P4-16-12: Does initial cardiac imaging impact clinical outcomes in patients with breast cancer?

Background: Echocardiography (echo) and multigated acquisition (MUGA) scans are the most commonly used modalities to assess cardiac function during breast cancer (BC) treatment. However, a case series of 176 patients with cancer suggests enhanced cardiac care with echo surveillance. We hypothesized that patients with early BC imaged by echo have improved cardiac outcomes compared to those imaged by MUGA.

Methods: Consecutive patients with stage I to III breast cancer undergoing pre-treatment echo or MUGA were retrospectively screened from January 2010 to December 2014. Patients participating in clinical trials with mandated imaging and/or cardiac reviews were excluded. Demographics, medical history and clinical events were collected via chart review and electronic health records. All patients had a minimum 1 year of follow-up. The primary outcome was a composite of death, cardiac hospitalization or cardiac emergency room visit.

Results: 598 patients were identified as having a baseline echo and 636 had had baseline MUGA. Mean follow-up was 4.5±1.4 years. Patients undergoing MUGA were younger, had more advanced stage of disease and received more anthracycline and trastuzumab (table1). Patients imaged by MUGA had lower cardiac function at baseline compared to echo, LVEF 64% vs. LVEF 65% respectively, P <0.001. Cancer therapy related cardiac dysfunction was similar between groups, 10% vs. 11%, p=0.81. Patients in the echo group were more likely to be seen by cardiology, 7% vs. 3%, p<0.0001, and to be initiated on beta blocker, 4% vs. 1%, p=0.006, or angiotensin converting enzyme inhibitor, 3% vs. 1%, p=0.002.However, there was no difference between groups for the primary outcome, 10% event rate in each group, even after adjustment for age, BC stage, chemotherapy and cardiac medications, hazard ratio 1.04 (CI 0.72-1.49), p=0.842.

Conclusion: For patients with early stage BC, the choice of cardiac imaging modality at baseline does not impact adverse cardiac events. However, patients undergoing echo were more likely to be evaluated and managed by cardiology.

Table 1.Baseline Characteristics Echo (N=598)MUGA (N=636)Age mean54±1053±10*BMI mean29±629±7Cardiovascular HistoryDiabetes66(11%)56(9%)Hypertension154(26%)155(24%)Dyslipidemia83(14%)75(12%)CAD9(2%)6(1%)CHF7(1%)4(1%)Beta Blocker22(4%)28(4%)ACE-Inhibitor51(9%)64(10%)Angiotensin Receptor Blocker69(12%)44(7%)*Cancer HistoryStage*Stage I65(11%)56(9%)Stage II377(63%)361(57%)Stage III155(26%)219(34%)Receptor StatusTriple negative64(11%)76(12%)HER2 negative, hormone positive342(58%)387(61%)HER2 positive192(32%)173(27%)Cancer TherapyChemotherapy (any)528(88%)594(93%)*Anthracycline310(52%)394(62%)*Trastuzumab170(28%)148(23%)*Anthracycline & trastuzumab6(1%)19(3%)*Hormone therapy459(77%)487(77%)Radiation (any)487(81%)527(83%)Radiation left side237(49%)259(49%)Surgery597(100%)633(100%)* p<0.05 for comparison between echo and MUGA groups

Citation Format: Parent S, Xu L, Becher H, Mackey J, King K, Pituskin E, Paterson I. Does initial cardiac imaging impact clinical outcomes in patients with breast cancer? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-16-12.

Abstract P6-13-08: A novel comparative analysis approach to personalize chemotherapy dose in early breast cancer

Background: Worldwide, body surface area [BSA] is used to calculate chemotherapy dose. The BSA formula was originally developed in 1916, derived from height and weight, with no consideration of other patient characteristics. Most chemotherapy agents have a narrow therapeutic index and are distributed in lean body mass [LBM], leading to under- or over-dosing and deleterious effects to major organs when body composition is not considered. To date, while experts worldwide acknowledge the limitations and risks of BSA dosing, no practical approach to personalizing chemotherapy dose has been developed. Ideally, body composition would be assessed by tests already routinely performed, avoiding unnecessary radiation exposure, clinic visits, discomfort to the patient, and cost. The majority of patients undergo cardiac imaging prior to chemotherapy. We hypothesized that clinical parameters routinely performed prior to chemotherapy could predict LBM in early breast cancer patients.

Method: Early stage breast cancer patients (n = 45) enrolled in the Multidisciplinary Team Intervention in Cardio-Oncology (TITAN) study underwent pre-treatment cardiac MRI, body composition (iDEXA) and laboratory (complete blood cell count and chemistry). Cardiac MRI and iDEXA are considered 'gold standard' imaging modalities, the accuracy of which allow for significantly reduced sample size.

Our modeling approach, which is novel in this area, aimed to select the best combination of parameters with the most predictive ability of total lean mass (iDEXA). The parameters included in study are: cardiac MRI metrics (LV mass, cardiac output), and laboratory parameters associated with major organ function (albumin, creatinine, bilirubin). All parameters were tested using univariate, multivariate and subset selection approach. Akaike's Information Criterion (AIC) was used to measure model quality, with lower AIC values indicating closer prediction.

Results: The univariate analysis of each parameter independently showed LV mass is most predictive with AIC 857.8, while combination of all parameter in multivariate fashion show improvement in prediction with AIC 851. The subset selection approach shows, Adjusted R2 with 4 parameters had AIC 849.14, Schwartz's information criterion (BIC) with 2 parameters had AIC 849.66 and Mallows' C Selection (Cp) model with 3 parameters had the least AIC 848.71 value (P < 0.001).

Conclusion: Our comparative analysis showed that the Cp model with 3 parameters (LV mass, cardiac output and bilirubin) has high prediction ability of LBM. This model will form the basis of a personalized formula for chemotherapy dose calculation. We expect this work to result in optimal cancer-specific outcomes while reducing short and long-term toxicities associated with necessary chemotherapy.

Citation Format: Perri MD, Singhal S, Hegadoren K, Norris C, Mackey J, Paterson I, Pituskin E. A novel comparative analysis approach to personalize chemotherapy dose in early breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-13-08.

Beta blockers and improved progression-free survival in patients with advanced HER2 negative breast cancer: a retrospective analysis of the ROSE/TRIO-012 study

BACKGROUND

Recent retrospective studies suggest that beta-adrenergic blocking drugs (BB) are associated with improved outcomes in patients with a range of cancers. Although limited and discordant data suggest that BB may increase overall survival (OS) in localized breast cancer (BC), there is no information on the effects of BB in women with advanced BC.

PATIENTS AND METHODS

To explore the association between BB use and BC outcomes, we retrospectively reviewed ROSE/TRIO-012, a double-blinded, multinational phase III trial that randomized 1144 patients with HER2-negative advanced BC to first-line docetaxel in combination with ramucirumab or placebo. We compared progression-free survival (PFS), OS, overall response rate, and clinical benefit rate in patients who received BB to those who did not.

RESULTS

153/1144 (13%) patients received BB; 62% prior to enrolment and 38% began after enrolment. Median PFS in BB treated patients was longer than in patients who did not receive them (10.3 versus 8.3 months; HR 0.81; 95% CI 0.66-0.99; P = 0.038). Patients treated with BB only after enrolment had even higher median PFS (15.5 versus 8.3 months, P < 0.001). In the TNBC subset, median PFS was 13.0 months with BB, compared to 5.2 months without BB (HR 0.52; 95% CI 0.34-0.79; P = 0.002). The benefit of BB intake in PFS was independent of treatment-emergent hypertension (P = 0.476) but associated with treatment arm (P = 0.037). The test for interactions between BB and treatment arm was not significant (P = 0.276). No differences were seen in OS, overall response rate, or clinical benefit rate. A validation dataset analysis had consistent but less substantial improved outcomes for women with node positive operable breast cancer receiving BB in the BCIRG-005 trial.

CONCLUSIONS

In this exploratory analysis, BB intake was associated with significant improvement in PFS, particularly in patients with TNBC and patients not previously exposed to BB.

CLINICAL TRIAL NUMBER

NCT00703326.

Abstract P4-10-16: Long term effects of trastuzumab on cardiopulmonary and left ventricular function in women with HER2 overexpressing breast cancer

Background: Adjuvant trastuzumab (TRZ) is the standard of care for HER2-overexpressing (HER2+) early stage breast cancer (EBC) patients (PTS), with five-year survival rates exceeding 90%. However, significant cardiac toxicities are observed, with a fivefold increase in clinical heart failure (HF). Left ventricular (LV) remodeling (increased heart size and mass) is an early indicator of cardiac injury, progressing to further LV dysfunction, reduced exercise tolerance and overt HF. Therefore, effective prevention of such negative sequelae is of enormous clinical interest. As the pivotal TRZ trials assessed cardiac function with MUGA or echocardiography, insensitive modalities to evaluate LV remodeling, the long-term sequelae of TRZ remain unknown.

Objective: to determine the long term effects of trastuzumab on cardiopulmonary and left ventricular function in women with HER2 overexpressing breast cancer. Additionally as aerobic training is an effective intervention in HF PTS who adhere to prescribed exercise, a sub-analysis compared those who adhered during a 4 month exercise intervention (AEX) vs those who did not adhere (NEX).

Methods: 16 PTS (mean age 58 ± 7) who participated in an exercise intervention study during the first 4 months of TRZ therapy were recruited, with an average of 4 years elapsing since TRZ completion. Cardiopulmonary exercise (VO2peak) testing and resting cardiac MRI (CMR) were performed and compared with baseline and 4 month assessments. Adherence to exercise intevention was defined as attendance ≥80% prescribed sessions.

Results: All 16 PTS reported independent living with no limitations to ADLs. At 4 years, mean VO2peak for all PTS was 22.4 ml/kg/min (20.0 at baseline and 22.0 at 4 months). In AEX PTS, higher VO2peak persisted 4 years after cessation of therapy, 4.1 mL/kg/min higher than NEX PTS (24.9 and 20.8 mL/kg/min, respectively ). Mean LVEF for all PTS was 60 ± 6%, not significantly different from baseline or 4 months (61 ± 5 and 55 ± 4%, respectively) . Statistically significant interactions of exercise adherence to other CMR metrics were not observed.

Conclusions: Clinically significant impairment of cardiopulmonary function (equal to 14 years of aging) are present before therapy and persist in PTS four years following exposure to TRZ-based chemotherapy. This observation is consistent with our other work, and occurs on a background of normal LVEF, implying additional negative effects to other components of the oxygen cascade. As mortality risk has been shown to decrease by 17% for every 3.5 mL/kg/min difference in aerobic capacity in healthy females, these findings indicate adherence to exercise interventions during TRZ-based therapy has potentially important long-term implications.

Citation Format: Pituskin E, Paterson I, Ghosh S, Mackey JR, Haykowsky MJ. Long term effects of trastuzumab on cardiopulmonary and left ventricular function in women with HER2 overexpressing breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-10-16.

Cardiovascular MRI predicts 5-year adverse clinical outcome in heart transplant recipients

Imaging recommendations for the follow-up of heart transplant recipients (HTRs) lack evidence justifying their prognostic value. Cardiovascular magnetic resonance imaging (CMRI) can characterize heart structure and function and has prognostic value in many myocardial diseases. We hypothesized that CMRI evaluation of cardiac allografts would predict adverse events. We performed CMRI on 60 HTRs evaluating biventricular size, function and myocardial scar. We performed survival analysis to identify independent predictors of cardiovascular (CV) death or hospitalization. Participants had a mean age of 51 ± 14 years, mean graft age of 3.5 years (±4) and 75% are male. Median follow-up time was 4.9 years with 22 CV hospitalizations and 7 CV deaths. A multivariable survival analysis of imaging and clinical variables identified myocardial scar (hazard ratio [HR] of 10.7, p = 0.005), right ventricular end- diastolic volume index (RVEDVI; 1.1/mL/m(2) , p = 0.001), graft age (HR = 1.2/year, p = 0.004) and previous allograft rejection (HR = 4.4, p = 0.006) as predictive of time to CV death or hospitalization. CMRI-derived myocardial scar and RVEDVI are independently associated with CV outcomes in HTRs.

Mitochondrial DNA mutations in head and neck cancer are infrequent and lack prognostic utility

Background:

Mitochondrial DNA (mtDNA) mutations occur in head and neck squamous cell carcinoma (HNSCC) and are most frequently detected in the displacement-loop (D-loop) region. The D-loop is considered to be important because it controls mitochondrial gene expression and mtDNA replication. There is currently no evidence that mtDNA mutations can be used as prognostic or predictive biomarkers in HNSCC.

Methods:

We used denaturing high performance liquid chromatography to screen the entire mitochondrial genome of six oral squamous cell carcinoma-derived cell lines and then focused on detecting D-loop abnormalities in 34 HNSCC tissue samples.

Results:

Mitochondrial DNA mutations are not ubiquitous in HNSCC because only half of the cell lines had detectable mtDNA abnormalities following screening of the entire mitochondrial genome and only 18% (6 of 34) of tissue samples had D-loop mutations. There was no correlation between D-loop mutations and determinates of clinical outcome; specifically, tumour stage and the expression of hypoxia-inducible genes included in a highly prognostic hypoxia metagene.

Conclusions:

Taken together, these data suggest that mtDNA D-loop mutations are stochastic events that may not significantly influence the biology of HNSCC and supports the hypothesis that mtDNA mutations in cancer represent bystander genotoxic damage as a consequence of tumour development and progression.

Menopausal symptoms in women treated for breast cancer: the prevalence and severity of symptoms and their perceived effects on quality of life

OBJECTIVES

To determine, first, the prevalence and severity of various symptoms related to estrogen deficiency in women within a few years of receiving treatment for breast cancer, second, how women perceive the effects of these symptoms on their quality of life and, third, what measures have been taken to relieve vasomotor symptoms.

METHODS

Two hundred women (aged 29-65 years) who had received treatment for breast cancer within the last 5 years were included in this cross-sectional survey. Information was collected about their breast cancer treatment, menopausal symptoms (Menopausal Rating Scale), the perceived effects of menopausal symptoms on their and their partner's quality of life and any treatments they were receiving for hot flushes.

RESULTS

All but one woman reported at least one symptom related to the menopause (95.9% vasomotor; 83.3% psychological; 89.7% somatic). Current treatment with tamoxifen or previous chemotherapy did not influence the prevalence or the severity of hot flushes. Current antidepressant treatment was, however, significantly associated with a higher prevalence and severity of most menopausal symptoms, including hot flushes and sweats (p = 0.008). The severity of hot flushes and sweats was significantly correlated with self-assessed effects on overall quality of life (r(s) = 0.47); 56.4% of the respondents believed that menopausal symptoms had affected their partner's quality of life, the strongest correlations being with severity of sexual symptoms (r(s) = 0.56) and vaginal dryness (r(s) = 0.5). Only 21% of women experiencing hot flushes were receiving any treatment for hot flushes, with most women describing no knowledge or poor knowledge of treatment options.

CONCLUSIONS

The majority of women receiving treatment for breast cancer report menopausal symptoms, which negatively correlate, not only with their own, but also with their partner's quality of life. Most women experiencing hot flushes are not receiving treatment due to lack of both awareness and confidence in the existing treatment options.

Total synthesis of the microtubule-stabilizing agent (-)-laulimalide

[structure: see text] The total synthesis of the potent microtubule-stabilizing anticancer agent (-)-laulimalide has been achieved in 27 steps and 2.9% overall yield. Notable features are the use of Jacobsen HDA chemistry for the enantioselective construction of the side chain dihydropyran, a diastereoselective aldol coupling using chiral boron enolate methodology, a Mitsunobu macrolactonization, and a Sharpless AE to introduce the epoxide onto des-epoxy-laulimalide.

A practical synthesis of (+)-discodermolide and analogues: fragment union by complex aldol reactions

A practical stereocontrolled synthesis of (+)-discodermolide (1) has been completed in 10.3% overall yield (23 steps longest linear sequence). The absolute stereochemistry of the C(1)-C(6) (7), C(9)-C(16) (8), and C(17)-C(24) (9) subunits was established via substrate-controlled, boron-mediated, aldol reactions of the chiral ethyl ketones 10, 11, and 12. Key fragment coupling reactions were a lithium-mediated, anti-selective, aldol reaction of aryl ester 8 (under Felkin-Anh induction from the aldehyde component 9), followed by in situ reduction to produce the 1,3-diol 40, and a (+)-diisopinocampheylboron chloride-mediated aldol reaction of methyl ketone 7 (overturning the inherent substrate induction from the aldehyde component 52) to give the (7S)-adduct 58. The flexibility of our overall strategy is illustrated by the synthesis of a number of diastereomers and structural analogues of discodermolide, which should serve as valuable probes for structure-activity studies.

Synthesis of the macrocyclic core of laulimalide

[figure: see text] A stereoselective synthesis of 3, corresponding to the fully functionalized macrocyclic core of the novel microtubule-stabilizing agent, laulimalide, has been completed. Efficient macrolactonization was achieved by a Mitsunobu reaction, installing the sensitive (Z)-enoate, and macrocyclic stereocontrol was then exploited to introduce the methyl group and trans-epoxide.

Studies in marine polypropionate synthesis: total synthesis of (-)-baconipyrone C

[reaction--see text] An asymmetric total synthesis of the unusual siphonariid metabolite, (-)-baconipyrone C (3), is described. Key steps included a tin(II)-mediated aldol coupling for the preparation of the carboxylic acid 17 and two different boron-mediated aldol additions leading to alcohol 8. Ester formation using modified Yamaguchi conditions gave 24, leading on PMB deprotection to (-)-baconipyrone C.

Total Synthesis of the Antimicrotubule Agent (+)-Discodermolide Using Boron-Mediated Aldol Reactions of Chiral Ketones

With a similar mechanism of action to taxol, the title compound 1 is a particularly promising candidate for development in cancer chemotherapy. This efficient synthesis, based on stereocontrolled aldol reactions, should help to overcome the scarce natural supply of 1 from the rare sponge source.

DNA studies underestimate the major role of CDKN2A inactivation in oral and oropharyngeal squamous cell carcinomas

Loss of CDKN2A expression was demonstrated by immunohistochemistry in 87% of oral and oropharyngeal squamous cell carcinoma (OSCC) primary tumor samples. By contrast, DNA studies showed a much lower frequency of loss of the CDKN2A gene. Point mutations and promoter methylation of CDKN2A were seen in 7% and 23%, respectively, of primary tumors. Loss of heterozygosity analysis using a dense set of 9p markers showed allelic imbalance that included CDKN2A in only 31% of samples, but a further 47% showed loss at loci near CDKN2A with apparent retention of CDKN2A. No tumor with any allelic imbalance expressed CDKN2A, whether or not the imbalance appeared to involve the CDKN2A locus. We interpret these data as showing partially overlapping deletions on the two 9p homologues, with homozygous deletion of CDKN2A masked by amplification of contaminating stromal material. Our data show that inactivation of the CDKN2A gene products is a near-universal step in the development of oral and oropharyngeal squamous cell carcinomas, and we suggest that homozygous deletion is the most common mechanism of inactivation. The CDKN2A locus may be particularly prone to deletion because it encodes two unrelated tumor suppressor proteins, CDKN2A (p16INK4a) and p19ARF, and deletion, but not point mutation or methylation, would inactivate both gene products. However, our results also suggest that complex patterns of allelic imbalance in primary squamous carcinomas in general may not provide reliable evidence for the existence of multiple tumor suppressor genes within a single chromosomal region.

Effect of rotation on periprosthetic bone mineral measurements in a hip phantom

The effect of rotation on the measurement of periprosthetic bone mineral content and bone mineral density using dual energy xray absorptiometry was studied in 9 anatomic specimen femora implanted with noncemented titanium hip prostheses. An apparatus was constructed to permit accurate femoral rotation through an arc of 30 degrees internal to 30 degrees external rotation in 5 degrees increments. Two scans were obtained at each increment of rotation for a total of 26 scans for each implanted femur. Change in bone mineral content and bone mineral density was measured for each of 7 contiguous periimplant regions (Gruen zones). The precision of the paired bone mineral density measurements was 1.7%. In all Gruen zones, the means of bone mineral content and bone mineral density measurements varied within 5% between 15 degrees internal and 15 degrees external rotation. Variation in limb rotation, as might occur with temporal studies of periimplant bone remodeling, can be tolerated within easily controllable limits without excessive error in bone mineral measurements.

Interleukin-2 induces early multisystem organ edema mediated by neutrophils

Interleukin-2 (IL-2), an agent known to activate neutrophils (PMN) with thromboxane (Tx)B2 release, produces pulmonary edema within 6 hours of intravenous infusion. This study tests the role of PMN in mediating the edema. Anesthetized rats received 10(6)U recombinant human IL-2 (n = 15) or vehicle (n = 14) as a constant intravenous infusion during a period of 1 hour. At this time there was leukopenia 3.63 +/- 0.43 (x10(3)/mm3) relative to vehicle-infused control rats 6.12 +/- 0.86 and a decline in PMN, 2.19 +/- 0.14 relative to control value of 3.33 +/- 0.05 (both p less than 0.05). After 6 hours edema, as measured by increase in the wet to dry weight (W/d) ratio, was present in the lungs (4.93 +/- 0.20 relative to control 4.06 +/- 0.10), heart (4.09 +/- 0.11 versus 3.76 +/- 0.08), liver (3.50 +/- 0.10 versus 3.18 +/- 0.10), and kidney (4.25 +/- 0.07 versus 4.00 +/- 0.07) (all p less than 0.05). There was increased lung permeability demonstrated by bronchoalveolar lavage fluid protein concentration of 1970 +/- 210 micrograms/mL relative to control 460 +/- 90 micrograms/mL (p less than 0.05). Interleukin-2 resulted in lung PMN sequestration of 53 +/- 7 PMN/10 high-power fields (HPF) relative to 23 +/- 2 PMN/10 HPF in controls (p less than 0.05) and increased plasma TxB2 levels to 1290 +/- 245 pg/mL relative to control 481 +/- 93 pg/mL (p less than 0.05). Pretreatment of other rats (n = 8) with selective anti-rat neutrophil antiserum 18 hours before the experiment led to a peripheral PMN count 10% of baseline and prevented edema in the lungs (W/d ratio 4.20 +/- 0.16) and heart (3.67 +/- 0.07) (both p less than 0.05) but not liver or kidney. Protein in lung lavage was reduced to 760 +/- 220 micrograms/mL (p less than 0.05). The protection afforded by leukopenia was associated with lack of PMN sequestration and prevention of the increase in plasma Tx levels (484 +/- 120 pg/mL, p less than 0.05). These data indicate that the rapid induction of lung and heart edema with a 1-hour infusion of IL-2 in the rat is mediated, in large part, by activated PMNs.