Abstract PD4-04: Role of breast MRI in predicting pathologically negative nodes after neoadjuvant chemotherapy in cN0 patients in the I-SPY2 trial

Background

In clinically node-negative (cN0) breast cancer patients with triple negative (TN) and HER2+ disease and breast pathological complete response (breast pCR), low rates of nodal positivity after neoadjuvant chemotherapy (NAC) have been demonstrated. In these patients, the omission of surgical axillary staging has been proposed. However, this information is not routinely known preoperatively. We aimed to validate the correlation between pathologic breast response and pathologic nodal status, and evaluate the relationship between response of the breast tumor on MRI and pathologic nodal status after NAC in cN0 patients in the I-SPY2 trial.

Methods

We identified all patients with cT1-4 cN0 breast cancer prior to NAC from graduated arms of the I-SPY2 trial, a prospective neoadjuvant chemotherapy trial. Absence of residual disease post-NAC was defined as longest diameter (LD) of 0 mm on MRI. Breast pCR was defined as the absence of invasive tumor in the breast at surgery. Associations between ypN0 and patient, MRI, and tumor characteristics were assessed using chi-square tests and univariate regression.

Results

Of 365 cT1-4 cN0 patients included, 128 had HR+/HER2- tumors (35%), 60 HR+/HER2+ tumors (16%), 34 HR-/HER2+ tumors (9%) and 143 TN tumors (39%). Overall, 283 patients (78%) were ypN0 after NAC and 152 patients (42%) had a breast pCR. ypN0 rate was higher in patients with a breast pCR than those with residual disease (93% vs 66%, p<0.001). Patients with HR-/HER2+ and TN tumors were more likely to be ypN0 (97% and 87% respectively) than patients with HR+/HER2- and HR+/HER2+ disease (66% and 71% respectively, p<0.001). Other characteristics associated with ypN0 were tumor grade (grade I 57%, grade II 66%, grade III 84%; p=0.002), MammaPrint Classification (High Risk 1 68% and High Risk 2 87%; p<0.001) and absence of residual tumor in the breast on MRI (87% vs 72% in patients with evidence of tumor on MRI post-NAC/pre-surgery; p=0.003).

In patients with HR-/HER2+, HR+/HER2+, HR-/HER2+ or TN disease and a breast pCR, ypN0 rate was respectively 82%, 96%, 96% and 97% (table 1). In patients with HR+/HER2-, HR+/HER2+, HR-/HER2+ or TN disease and with no evidence of residual disease in the breast on MRI, rate of ypN0 was 71%, 80%, 94% and 96% respectively.

Conclusion

In cT1-4 cN0 breast cancer patients with HR+/HER2+, HR-/HER2+ and TN tumors and a breast pCR, ypN0 rates after NAC are extremely high. In patients with HR-/HER2+ and TN tumors with no residual breast disease on MRI after NAC and pre-surgery, ypN0 rates are high enough to consider omission of axillary surgery. In patients with HR+ tumors, MRI is unsufficiently predictive for pathological response and can therefore not be used to select ypN0 patients. Research on the prediction of ypN0 in cN+ I-SPY2 patients is ongoing.

Nodal status in patients with pCR and absence of residual disease on MRI Number of positive nodesBreast Cancer Subtype0123AllBreast pCR     HR+/HER2-27(82)2(6)4(12)033(100)HR+/HER2+24(96)01(4)025(100)HR-/HER2+24(96)1(4)0025(100)TN67(97)2(3)0069(100)Absence of residual disease on MRI     HR+/HER2-24(71)7(21)3(9)034(100)HR+/HER2+16(80)3(15)01(5)20(100)HR-/HER2+15(94)1(6)0016(100)TN54(96)2(4)0056(100)

Citation Format: van der Noordaa ME, Esserman L, Yau C, Mukhtar R, Price E, Hylton N, Abe H, Wolverton D, Crane EP, Ward KA, Nelson M, Niell BL, Oh K, Brandt KR, Bang DH, Ojeda-Fournier H, Eghtedari M, Sheth PA, Bernreuter WK, Umphrey H, Rosen MA, Dogan B, Yang W, Joe B, van 't Veer L, Hirst G, Lancaster R, Wallace A, Alvaredo M, Symmans F, Asare S, Boughey JC, I-SPY2 Consortium. Role of breast MRI in predicting pathologically negative nodes after neoadjuvant chemotherapy in cN0 patients in the I-SPY2 trial [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 PD4-04.

Abstract P2-07-03: Refining neoadjuvant predictors of three year distant metastasis free survival: Integrating volume change as measured by MRI with residual cancer burden

Background: Patients achieving a pathologic complete response (pCR) following neoadjuvant therapy have significantly improved event-free survival relative to those who do not; and pCR is an FDA-accepted endpoint to support accelerated approval of novel agents/combinations in the neoadjuvant treatment of high risk early stage breast cancer. Previous studies have shown that recurrence risk increased with increasing burden of residual disease (as assessed by the RCB index). As well, these studies suggest that patients with minimum residual disease (RCB-I class) also have favorable outcomes (comparable to those achieving a pCR) within high risk tumor subtypes. In this study, we assess whether integrating RCB with MRI functional tumor volume (FTV), which in itself is prognostic, can improve prediction of distant recurrence free survival (DRFS); and identify a subset of patients with minimal residual disease with comparable DRFS as those who achieved a pCR. Imaging tools can then be used to identify the subset that will do well early and guide the timing of surgical therapy.

Method: We performed a pooled analysis of 596 patients from the I-SPY2 TRIAL with RCB, pre-surgical MRI FTV data and known follow-up (median 2.5 years). We first assessed whether FTV predicts residual disease (pCR or pCR/RCB-I) using ROC analysis. We applied a power transformation to normalize the pre-surgical FTV distribution; and assessed its association with DRFS using a bi-variate Cox proportional hazard model adjusting for HR/HER2 subtype. We also fitted a bivariate Cox model of RCB index adjusting for subtype; and assessed whether adding pre-surgical FTV to this model further improves association with DRFS using a likelihood ratio (LR) test. For the Cox modeling, penalized splines approximation of the transformed FTV and RCB index with 2 degrees of freedom was used to allow for non-linear effects of FTV and RCB on DRFS.

Result: Pre-surgical MRI FTV is significantly associated with DRFS (Wald p<0.00001), and more effective at predicting pCR/RCB-I than predicting pCR alone (AUC: 0.72 vs. 0.65). Larger pre-surgical FTV remains associated with worse DRFS adjusting for subtype (Wald p <0.00001). The RCB index is also significantly associated with DRFS adjusting for subtype (Wald p<0.00001). Adding FTV to a model containing RCB and subtype further improves association with DRFS (LR p=0.0007). RCB-I patients have excellent DRFS (94% at 3 years compared to 95% in the pCR group). Efforts are underway to identify an optimal threshold for dichotomizing pre-surgical FTV and FTV change measures for use in combination with pCR/RCB-I class to generate integrated RCB (iRCB) groups as a composite predictor of DRFS.

Conclusion: Pre-surgical MRI FTV is effective at predicting minimal residual disease (RCB0/I) in the I-SPY 2 TRIAL. Despite the association between FTV and RCB, FTV appears to provide independent added prognostic value (to RCB and subtype), suggesting that integrating MRI volume measures and RCB into a composite predictor may improve DRFS prediction.

Citation Format: Hylton NM, Symmans WF, Yau C, Li W, Hatzis C, Isaacs C, Albain KS, Chen Y-Y, Krings G, Wei S, Harada S, Datnow B, Fadare O, Klein M, Pambuccian S, Chen B, Adamson K, Sams S, Mhawech-Fauceglia P, Magliocco A, Feldman M, Rendi M, Sattar H, Zeck J, Ocal I, Tawfik O, Grasso LeBeau L, Sahoo S, Vinh T, Yang S, Adams A, Chien AJ, Ferero-Torres A, Stringer-Reasor E, Wallace A, Boughey JC, Ellis ED, Elias AD, Lang JE, Lu J, Han HS, Clark AS, Korde L, Nanda R, Northfelt DW, Khan QJ, Viscusi RK, Euhus DM, Edmiston KK, Chui SY, Kemmer K, Wood WC, Park JW, Liu MC, Olopade O, Tripathy D, Moulder SL, Rugo HS, Schwab R, Lo S, Helsten T, Beckwith H, Haugen PK, van't Veer LJ, Perlmutter J, Melisko ME, Wilson A, Peterson G, Asare AL, Buxton MB, Paoloni M, Clennell JL, Hirst GL, Singhrao R, Steeg K, Matthews JB, Sanil A, Berry SM, Abe H, Wolverton D, Crane EP, Ward KA, Nelson M, Niell BL, Oh K, Brandt KR, Bang DH, Ojeda-Fournier H, Eghtedari M, Sheth PA, Bernreuter WK, Umphrey H, Rosen MA, Dogan B, Yang W, Joe B, I-SPY 2 TRIAL Consortium, Yee D, Pusztai L, DeMichele A, Asare SM, Berry DA, Esserman LJ. Refining neoadjuvant predictors of three year distant metastasis free survival: Integrating volume change as measured by MRI with residual cancer burden [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 P2-07-03.

Failure mode and effects analysis of the universal anaesthesia machine in two tertiary care hospitals in Sierra Leone

Background

Anaesthesia care in developed countries involves sophisticated technology and experienced providers. However, advanced machines may be inoperable or fail frequently when placed into the austere medical environment of a developing country. Failure mode and effects analysis (FMEA) is a method for engaging local staff in identifying real or potential breakdowns in processes or work systems and to develop strategies to mitigate risks.

Methods

Nurse anaesthetists from the two tertiary care hospitals in Freetown, Sierra Leone, participated in three sessions moderated by a human factors specialist and an anaesthesiologist. Sessions were audio recorded, and group discussion graphically mapped by the session facilitator for analysis and commentary. These sessions sought to identify potential barriers to implementing an anaesthesia machine designed for austere medical environments—the universal anaesthesia machine (UAM)—and also engaging local nurse anaesthetists in identifying potential solutions to these barriers.

Results

Participating Sierra Leonean clinicians identified five main categories of failure modes (resource availability, environmental issues, staff knowledge and attitudes, and workload and staffing issues) and four categories of mitigation strategies (resource management plans, engaging and educating stakeholders, peer support for new machine use, and collectively advocating for needed resources).

Conclusions

We identified factors that may limit the impact of a UAM and devised likely effective strategies for mitigating those risks.

[Interdisciplinary training opportunities for residents in occupational medicine: the experience of the ERC Tour 2012]

This paper describes the experience of the School of Occupational Medicine of the University of Brescia at the current edition of the New York and New Jersey Education and Research Center--Historical Perspectives Tour on Occupational Safety and Health, that involved 5 different industrial and environmental sites, appropriate for understanding the complex occupational health and safety problems. In every site, the participants have interacted with workers and professionals and discussed about the specific work processes, to better understand the risk faced by the workers, occupational pathologies that can occur, personal protective equipment used and preventive measures adopted. This experience has been successful in provide interdisciplinary educations to occupational safety and health professionals in training in order to prepare them for the collaboration and cooperation required to solve the complex occupational health and safety problems they will face in their future careers.

Energy and exergy analyses of a biomass-based hydrogen production system

In this paper, a novel biomass-based hydrogen production plant is investigated. The system uses oil palm shell as a feedstock. The main plant processes are biomass gasification, steam methane reforming and shift reaction. The modeling of the gasifier uses the Gibbs free energy minimization approach and chemical equilibrium considerations. The plant, with modifications, is simulated and analyzed thermodynamically using the Aspen Plus process simulation code (version 11.1). Exergy analysis, a useful tool for understanding and improving efficiency, is used throughout the investigation, in addition to energy analysis. The overall performance of the system is evaluated, and its efficiencies become 19% for exergy efficiency and 22% energy efficiency while the gasifier cold gas efficiency is 18%.

Response assessment of HCC undergoing chemoembolization by necrosis-adjusted models

e15528

Background: Chemoembolization (CE) is an accepted therapy for unresectable HCC. As treated tumors may not shrink in size, response assessment via measurement of the enhancing tumor (EASL) has been proposed as an alternate to whole tumor (RECIST) measures. However, the reliability of this model has not been tested in clinical practice. Methods: We identified 29 HCC patients treated with CE with known overall survival (OS) in whom MRI before and after initial CE therapy was available for review. Three radiologists evaluated the imaging, measuring the largest liver lesion in three dimensions and the largest enhancing region in two dimensions. Readers also assessed percent tumor necrosis and overall tumor response qualitatively. Response models in 1-, 2-, or 3- dimensions, with or without necrosis adjustment, were created to assign patients to CR/PR/SD/PD classes, based on majority classification. Predictive value for OS was assessed for PD vs. other, and for PR/CR vs. SD/PD by the Students’ t-test. Inter-reader concordance was assessed by the Fleiss κ statistic. Results: For non-necrosis adjusted models, OS for progressors vs. non-progressors was statistically significant (p values: 0.0002–0.04), but could not identify early responders. Necrosis adjusted models failed to identify early progressors, but identified responders with improved OS (p values: 0.02–0.12). Inter-reader concordance was higher for necrosis adjusted models (κ range: 0.36–0.52) than for non-necrosis adjusted models (0.16–0.23). Viable tumor response by a two-dimensional product was superior to a one-dimensional diameter for predicting OS (p=0.04 vs. 0.74), and demonstrated higher inter-reader concordance (κ=0.46 vs. 0.30). Qualitative assessment of hepatic tumor could predict differences in OS for both PD vs. others (p=0.0001) and responders vs. non-responders (p=0.04), with acceptable inter-reader concordance (κ=0.34). Conclusions: Two- dimensional, but not one-dimensional, viable tumor measurement can identify response of HCC to chemoembolization and predict OS. Models which incorporate qualitative reader assessment of tumor necrosis may be more flexible than direct measures of viable tumor, and should be considered as alternatives for tumor assessment in chemoembolization.

No significant financial relationships to disclose.

Phase II study of sorafenib and docetaxel in men with metastatic castration resistant prostate cancer (mCRPC)

e16055

Background: Previous trials of the antiangiogenic kinase inhibitor sorafenib in mCRPC have reported PSA elevation accompanying radiographic response, and evidence that sorafenib may potentiate docetaxel (dxl) myelosuppression. To assess the safety, antivascular effects, and activity of sorafenib and dxl in mCRPC, a phase II trial with dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) was conducted. Methods: Eligible men had mCRPC and no prior chemotherapy. Treatment consisted of dxl 75 mg/m2(day 1) and sorafenib (days 2–19) of a 21 day cycle. Patients received 7 days of sorafenib before cycle 1. Six patients received sorafenib 200mg BID and remaining patients received sorafenib 400 mg BID if <4/6 patients had grade 4 neutropenia. DCE-MRI was performed at baseline, days 8 and 28. The primary endpoint was PSA response rate (>50% PSA decline). Secondary endpoints were vascular response rate (>20% decline in area under the gadolinium curve [AUC60]), toxicity rates, and time to progression (TTP). PSA-only progression (2 consecutive PSA rises) was confirmed by a third PSA rise or radiographic progression after a 21-day drug holiday. Sample size of 69 patients in 1 stage was designed to maximize detection of significant correlations between DCE-MRI and clinical outcomes. Results: Six of 13 enrolled patients (46%) had a PSA response. A median PSA increase of 37% was observed in 73% of patients after 1 week of sorafenib. The median TTP was 8+ months. Two patients had complete disappearance of bone lesions. Grade 3 adverse events were neutropenia (77%), hand-foot syndrome (23%), anemia (15%), nausea (8%), and rash (8%). A median AUC60 decline of 40% from baseline was observed after 7 days of sorafenib, and only a 6% decline on day 28 during a scheduled sorafenib holiday. Conclusions: Sorafenib 400 mg po bid and dxl 75 mg/m2 are tolerable in men with mCRPC. Elevated PSA values in men treated with sorafenib and dxl does not always reflect disease progression. DCE-MRI can capture sorafenib's impairment of tumor vasculature in osseous metastases and rebound angiogenesis during drug holidays. Bone responses and TTP data provide evidence of encouraging activity.

No significant financial relationships to disclose.

Differentiation of benign and malignant breast lesions by in-vivo three-dimensional diffuse optical tomography

Abstract #805

Background: Diffuse optical tomography (DOT) uses near-infrared light to non-invasively image total hemoglobin concentration and blood oxygen saturation in the human breast. Given its low cost, ease of use, and possibility of repeated measured over time, DOT is a promising adjunctive imaging modality for screening, diagnosis and monitoring of neoadjuvant therapy. In this study we explored the performance of DOT to differentiate benign and malignant breast lesions.&#x2028; Method and Materials: Forty-seven women with clinical or mammographic abnormalities were prospectively recruited for DOT. Most patients underwent gadolinium-enhanced MRI examination. Three-dimensional oxy-, deoxy-hemoglobin, total hemoglobin concentration, blood oxygen saturation and scattering coefficient images of each breast were reconstructed. Tumor-to-normal (T/N) ratios of these parameters were computed by defining tumor regions with guidance from MRI and radiology reports. In addition, optical index was constructed based on these parameters to maximize the T/N contrast. Only the biopsy-proven lesions were selected (51 breast lesions) and classified into three groups: benign lesions (N=10), malignant lesions where DOT preceded core biopsy (N=20) and malignant lesions where DOT was performed after core-biopsy (N=21). We fit a mixed effects model that estimated the mean optical T/N ratios and optical index for each group, and using the resulting standard errors developed 95% confidence intervals and tested the hypothesis that each optical contrast parameter was unity.&#x2028; Results: Malignant cancers showed statistically significant higher total hemoglobin concentration, scattering, oxy-hemoglobin concentration and optical index (P=0.01-0.04) compared to normal tissue. Furthermore, malignant lesions exhibited a two-fold average increase in an optical index derived from the endogenous optical parameters (95% CI: 1.4 - 2.4). To test whether bleeding due to core biopsy influence DOT results, we compared if there was statistically significant differences between two groups measured before or after core-biopsy. There were no statistically significant differences in these groups, suggesting that post biopsy hemorrhage did not alter the DOT results. Benign tumors did not show statistical significance in all of the T/N ratios. AUC of total hemoglobin concentration, scattering, oxy-hemoglobin and optical index suggested good discriminatory power with values between 0.90 and 0.99.&#x2028; Discussion: The data demonstrates the feasibility of differentiating benign and malignant lesions by quantitative three-dimensional DOT when the tumor location information is provided by other imaging modality. The main drawback of this study is the small number of benign lesions, which warrants further study. DOT technology is still at its developing stage and needs more investigation to find its niche in breast imaging.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 805.

Comparison of MRI endpoints for assessing breast cancer response to neoadjuvant treatment: preliminary findings of the American College of Radiology Imaging Network (ACRIN) trial 6657

Abstract #6043

Background: ACRIN 6657, the imaging component of the I-SPY trial (CALGB 150007/150012), is a multi-center study testing the ability of MRI to provide in-vivo quantification of breast tumor response to neoadjuvant chemotherapy, for early prediction of response and stratification of risk-of-recurrence following treatment. We report results from preliminary analysis comparing MRI variables for correlation with pathologic response and disease progression. Methods: Women with ≥3 cm invasive breast cancer receiving an anthracycline-cyclophosphamide (AC) neoadjuvant chemotherapy regimen followed by a taxane (T) were enrolled between May 2002 and March 2006. Contrast-enhanced MRI was performed prior to start of treatment (baseline), following 1 cycle of AC chemotherapy (t2), between AC and T regimens (t3), and after all chemotherapy but prior to surgery (t4). MRI assessments included tumor longest diameter (MRLD), tumor volume (MRVol), and signal enhancement ratio (SER), a measure of contrast enhancement kinetics. Clinical size (cSize) and mammographic longest diameter (MGLD) were also recorded. Linear dimension was measured by the radiologist for MGLD and MRLD; MRVol was calculated by computer using SER thresholds. Pathologic residual disease size (pSize) and residual cancer burden (RCB) index were evaluated following surgery. Results: 237 patients were enrolled at 9 institutions. 216 patients with complete imaging formed the preliminary analysis set. At time of analysis 42 patients had progressed or died with mean time-to-progression of 21 months; 174 patients were progression-free with mean follow-up time of 42 months. At t4, MRVol was more strongly correlated with pSize than MRLD, SER or cSize (r=.61 vs .28, .24 and .43), while SER showed a stronger correlation with RCB than MRLD, MRVol or cSize (r = .45 vs .30, .31 and .37). MGLD at t4 did not show a significant correlation with either pSize or RCB. Early measurements of tumor size change from baseline by MRVol at t2, and MRVol, MRLD and SER at t3, all showed significant correlation with RCB. In univariate logistic regressions, all t4 measurements were found to be predictive of disease progression. Conclusion: Among clinical and imaging measurements of residual breast tumor size, MRI appears to most accurately reflect pathologic extent of disease following neoadjuvant treatment. Preliminary findings also suggest that tumor size and contrast kinetics measured by MRI may be useful early predictors of treatment response. ACRIN 6657 is continuing to collect follow-up data toward the primary aim testing MRI for stratification of post-treatment risk groups according to 3-year disease-free survival. This work is funded by NIH/ACRIN Grant U01 CA79778S2, CALGB Grants CA31946 and CA33601, and NCI SPORE Grant CA58207.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6043.

The impact of FDG PET in the staging of breast cancer

530

Background: To evaluate the impact of whole-body fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in staging breast cancer beyond the breast and axilla. Methods: 200 women, mean age 51 yrs (range 28–81) with breast cancer were enrolled in an IRB approved multi-modality imaging trial from 3/02 to 5/05. After imaging with film screen mammography ± ultrasound (US), patients underwent digital mammography, whole breast US, magnetic resonance imaging (MRI), and whole body FDG PET. Imaging reports and patient charts were reviewed and distant lesions were classified: 1 = no uptake; 2 = physiologic uptake; 3 = non-suspicious uptake; 4 = suspicious uptake without work-up; 5 = suspicious uptake with work-up. Decisions to forego work-up in class 4 lesions were clinical. Class 5 PET lesions were evaluated by confirmatory studies, including computed tomography (CT), MRI, x-ray (XR), bone scan (BS), or pathology. Patients also underwent standard staging with chest XR and BS per clinical judgment. Results: 189/200 (95%) women received PET scans. PET identified 71 distant areas of increased uptake in 42/189 (22%) women. 59/71 (83%) lesions were considered suspicious in 33/42 (79%) women: 50/59 (85%) lesions were class 5 and 9/59 (15%) class 4. Of the 50 class 5 lesions, 19 (38%) were true positive (TP) for neoplastic disease, 2 (4%) were TP for non-neoplastic disease, and 29 (58%) were false positive (FP). The positive predictive value (PPV) for class 5 lesions was 40%. The 19 TP distant sites of malignancy occurred in 6/189 (3%) patients; 4 of these patients (67%) also had TP distant sites identified by standard staging procedures. PET alone identified TP distant disease in 2/189 (1%) women. PET identified 29 FP findings in 22/189 (12%) patients. FP findings prompted 17 CTs, 8 XRs, 2 MRIs, and 1 BS. MRI revealed 2 additional neoplasms that had been false negatives (FN) by PET in 2/189 (1%) women. Conclusions: Whole-body FDG-PET added little additional information in staging our patients with known primary breast cancer, based on low PPV and equivalent TP and FN rates. Additionally, the high FP rate of PET in these patients may prompt unnecessary, costly, and invasive follow-up studies.

No significant financial relationships to disclose.

A phase II trial of combination of capecitabine, oxaliplatin with bevacizumab in treatment of advanced hepatocellular carcinoma (HCC): Preliminary safety analysis

14098

Background: Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world and the third leading cause of cancer-related death, with increasing incidence in USA. Most patients with HCC are unsuitable for surgery. There is no generally accepted ‘standard’ chemotherapy regimen for HCC because of the heterogeneity of disease and poor liver function in many patients. Continuous efforts have been made for investigating effective and tolerable therapy for patients with advanced HCC. This phase II study evaluates the feasibility and efficacy of the combination of bevacizumab, oxaliplatin, and capecitabine in patients with advanced/metastatic HCC. Methods: Patients with unresectable/untransplantable or metastatic HCC who have adequate bone marrow, liver and renal function (ANC ≥ 1,500/mm3, platelets ≥ 75,000/mm3, serum creatinine ≤ 2.0 mg/dl, total bilirubin ≤ 3.0 mg/dl, transaminases ≤ 5 upper limit of normal, and INR ≤ 1.5) are treated with the combination: intravenous bevacizumab (5 mg/kg) and oxaliplatin (130 mg/m2 over 2 hours) are administered on day 1 of each 21- day cycle. Capecitabine (825 mg/m2, twice a day) is given days 1 to 14. Results: To date, 17 patients (male/female: 14/3) with median age of 57 (range 27–76) have been treated. The mean number of treatment cycles is six. After 12 cycles of therapy, one patient was withdrawn from the treatment because of side effect; the other is continuing his 13th cycle of treatment. Six patients developed Gr. 2/3 oxaliplatin-related peripheral neuropathy and 4 patients had capecitabine-related Gr. 2/3 hand-foot syndrome. One patient had gastrointestinal perforation and sepsis right after his first administration of bevacizumab and oxaliplatin. There has been no treatment -related bleeding or arterial ischemia event noticed. Conclusions: The preliminary results suggest that the combination of bevacizumab, oxaliplatin, and capecitabine is encouraging and tolerable in treatment of patients with advanced HCC.

[Table: see text]

Anesthesia for fetal procedures and surgery

Many of the anesthetic considerations for fetal procedures and surgery are identical to those for nonobstetric surgery during pregnancy, including concern for maternal safety, avoidance of both teratogenic drugs and fetal asphyxia, and the prevention of preterm labor and delivery. Anesthesia is required for the mother and quite often the fetus to perform many fetal procedures. Fetal procedures and surgery can be divided into subgroups according to their anesthetic requirements. For example: procedures that only require a needle insertion into the uterus but not into the fetus, such as intrauterine infusions; laser surgical photocoagulation of the communicating placental circulation for twin-twin transfusion syndrome (TTTS) and radio-frequency umbilical cord ablation for managing twin reversed arterial perfusion (TRAP), which are not really fetal procedures, rather they are placental or cord procedures; surgical procedures performed directly on the fetus; and the EX-utero Intrapartum Treatment (EXIT) procedure. Anesthetic considerations also depend on other factors, such as the location of the placenta. Unlike maternal surgery, for fetal procedures, the fetus is not an innocent bystander for whom the least anesthetic interference is used. Instead, the fetus can be the primary patient and may benefit from anesthesia, with close monitoring of the anesthetic effects to ensure well-being. Fetal asphyxia, hypoxia, or distress can be most effectively recognized, predicted, and avoided by fetal monitoring. Monitoring is also crucial for assessing the fetal response to corrective maneuvers.

Imaging of hepatic steatosis

Hepatic steatosis is a common finding encountered during cross-sectional imaging examinations. This article reviews the imaging findings of hepatic steatosis as revealed by sonography, computed tomography, magnetic resonance imaging, and magnetic resonance spectroscopy. Focal fatty sparing and focal hepatic steatosis are conditions that can create potential diagnostic challenges for the radiologist. The typical findings, distribution, and etiology of these focal processes are presented. In the setting of diffuse hepatic steatosis, hepatic mass lesions can be difficult to discern on both computed tomography and sonography, with reported decreased sensitivity and specificity of lesion detection. In such cases, magnetic resonance imaging may be the imaging procedure of choice for the detection and characterization of both hepatic steatosis and coexistent hepatic masses. Some hepatocellular neoplasms, particularly hepatic adenoma and well-differentiated hepatocellular carcinoma, can have intratumoral lipid. By demonstrating the lipid content of these masses, imaging can add specificity in characterizing them as hepatocellular in origin because nonhepatocellular neoplasms in general do not contain intracellular lipid.

A human prostatic epithelial model of hormonal carcinogenesis

The effects of stromal and hormonal environment on the immortalized but nontumorigenic human prostatic epithelial cell line BPH-1 were investigated in an in vivo model. BPH-1 cells were recombined with rat urogenital sinus mesenchyme (UGM), and the tissue recombinants were grafted to the renal capsule of adult male athymic mouse hosts. BPH-1 + UGM recombinants formed solid branching epithelial cords with a well-defined basement membrane. The cords canalized to form ductal structures. The mesenchymal cells formed thick sheets of well-differentiated smooth muscle surrounding the epithelium, reinforcing the idea that the epithelium dictates the patterning of prostatic stromal cells. When hosts carrying BPH-1 + UGM tissue recombinants were exposed to testosterone propionate and 17-beta-estradiol (T + E2), the tissue recombinants responded by forming invasive carcinomas, demonstrating mixed, predominantly squamous as well as adenocarcinomatous (small acinar and mucinous) differentiation. When either untreated or T + E2-treated hosts were castrated, epithelial apoptosis was observed in the grafts. When tumors were removed and regrafted to fresh hosts they grew rapidly. Tumors were serially regrafted through six generations. Histologically these tumors consisted largely of focally keratinizing squamous cell carcinoma with high-grade malignant cytological features. BPH-1 cells grown in the absence of UGM survived at the graft site but did not form tumors or organized structures. This behavior was not influenced by the presence or absence of T + E2 stimulation. These data show that an immortalized, nontumorigenic human prostatic epithelial cell line can undergo hormonal carcinogenesis in response to T + E2 stimulation. In addition, the data demonstrate that the stromal environment plays an important role in mediating hormonal carcinogenesis.

Significant interaction between clozapine and cocaine in cocaine addicts

Because clozapine may be prescribed to cocaine abusing patients with schizophrenia, we studied cocaine-clozapine interactions in a controlled setting. Eight male cocaine addicts underwent four oral challenges with ascending doses of clozapine (12.5, 25 and 50 mg) and placebo followed 2 h later by a 2-mg/kg dose of intranasal cocaine. Subjective and physiological responses, and serum cocaine levels were measured over a total 4-h period. Clozapine pretreatment increased cocaine levels during the study and significantly increased the peak serum cocaine levels in a dose dependent manner. In spite of this elevation in blood levels, clozapine pretreatment had a significant diminishing effect upon subjective responses to cocaine, including 'expected high', 'high' and 'rush', notably at the 50 mg dose. There was also a significant effect upon 'sleepiness', 'paranoia' and 'nervous'. Clozapine caused a significant near-syncopal episode in one subject in the study, requiring his removal from the study. Clozapine had no significant effect on baseline pulse rate and systolic blood pressure, but it attenuated the significant pressor effects of the single dose of intranasal cocaine. These data suggested a possible therapeutic role for clozapine in the treatment of cocaine addiction in humans, but also suggests caution due to the near-syncopal event and the increase in serum cocaine levels.

Interactions between adult human prostatic epithelium and rat urogenital sinus mesenchyme in a tissue recombination model

Tissue recombinants composed of adult human prostatic epithelium (hPrE) and rat urogenital sinus mesenchyme (rUGM) were grafted beneath the renal capsule of athymic rodent hosts. The pseudostratified human epithelium initially became multilayered, solid epithelial cords emerged, grew into the surrounding mesenchyme and canalized to regenerate a pseudostratified epithelium. Basal cells expressed cytokeratins 5 and 14, while luminal cells expressed cytokeratins 8 and 18, prostate specific antigen and prostatic acid phosphatase. The rat mesenchymal component differentiated into thick sheets of smooth muscle, characteristic of the human but not the rat prostate. These findings indicate that epithelial-mesenchymal interactions were reciprocal. Rat UGM induced adult hPrE to form new ductal-acinar tissue, involving epithelial proliferation, ductal branching morphogenesis and functional cytodifferentiation. Concurrently the epithelium dictated smooth muscle differentiation and patterning. Species-specific reverse transcriptase polymerase chain reaction SC (RT-PCR) analysis of the tissue recombinants was performed to separately examine the expression of epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGFR), TGF-beta 1, and TGF-beta 3 in the epithelium, stroma and host components of the graft. All of these genes, except TGF-beta 1, were expressed in all three tissues. Human TGF-beta 1 was not detected, indicating that this gene was not expressed in human prostatic epithelium but was present in stroma.

Intravenous remifentanil: placental transfer, maternal and neonatal effects

BACKGROUND

Remifentanil has not been studied in obstetric patients. This study evaluates the placental transfer of remifentanil and the neonatal effects when administered as an intravenous infusion.

METHODS

Nineteen parturients underwent nonemergent cesarean section with epidural anesthesia and received 0.1 microg kg(-1) x min(-1) remifentanil intravenously, which was continued until skin closure. Maternal arterial (MA), umbilical arterial (UA), and umbilical venous (UV) blood samples were obtained at delivery for analysis of drug concentrations of remifentanil, its metabolite, and blood gases. Maternal vital signs were monitored continuously, and pain and sedation levels were assessed intermittently. Apgar scores were obtained at 1, 5, 10, and 20 min, and Neonatal and Adaptive Capacity Scores were noted 30 and 60 min after delivery. Parturients and newborns were observed for at least 24 h after surgery for side effects.

RESULTS

The means and SDs of UV:MA and UA:UV ratios for remifentanil were 0.88+/-0.78 and 0.29+/-0.07, respectively. Mean clearance was 93 ml x min(-1) kg(-1). The mean UV:MA and UA:MV ratios for remifentanil acid were 0.56+/-0.29 and 1.23+/-0.89, respectively. The mean MA (remifentanil acid):MA (remifentanil) ratio was 2.92+/-3.65. There were no adverse effects on the neonates, but there was a sedative effect and respiratory depressant effect on the mothers.

CONCLUSIONS

Remifentanil crosses the placenta but appears to be rapidly metabolized, redistributed, or both. Maternal sedation and respiratory changes occur, but without adverse neonatal or maternal effects.

Prophylactic ephedrine and hypotension associated with spinal anesthesia for cesarean delivery

Hypotension commonly accompanies induction of spinal anesthesia for cesarean section. To determine whether intravenous ephedrine prophylaxis would benefit prehydrated obstetrical patients presenting for elective cesarean section, we studied 30 patients randomly assigned to one of three experimental groups. All patients were preloaded with crystalloid (15 ml/kg), given spinal anesthesia and positioned with left uterine displacement (LUD). During induction, all patients received a 2 ml intravenous bolus and intravenous infusion of the study drug or placebo. The control group (n=10) received a saline bolus and saline infusion, the bolus group (n=10) received an ephedrine bolus (10 mg) and a saline infusion and the infusion group (n=10) received a saline bolus and a two-stage ephedrine infusion (20 mg over 12 min). After induction of anesthesia, systolic blood pressure decreased in the first 5 min in all groups. Hypotension occurred in 6/10 control patients, 5/10 bolus patients and 5/10 infusion patients. The amount of supplemental ephedrine required to treat hypotension did not differ among groups. Although the efficacy of ephedrine prophylaxis for hypotension associated with spinal anesthesia for elective cesarean section cannot be established by the small number of patients studied, this practice does not appear to be clinically relevant at the doses studied.

Correction of congenital diaphragmatic hernia in utero VII: a prospective trial

BACKGROUND

Congenital diaphragmatic hernia (CDH) remains an unsolved problem. Despite optimal postnatal care, up to 60% of CDH babies die. Experimental evidence and clinical experience have shown that in utero repair of CDH is feasible and can reverse pulmonary hypoplasia, but only in fetuses without liver herniation. For this subgroup, the safety and efficacy of repair before birth has not been compared with standard care after birth.

METHODS

Four fetuses in whom CDH without liver herniation was diagnosed underwent open fetal surgery for repair of the CDH. Seven comparison fetuses were treated conventionally. Neonatal mortality was the principle outcome variable. Secondary outcome variables included death of all causes until 2 years of age, number of days of ventilatory support, length of hospital stay, requirement for extracorporeal membrane oxygenation (ECMO), and total hospital charges.

RESULTS

There was no difference in survival between the fetal surgery group and the postnatally treated comparison group (75% v 86%). Fetal surgery patients were born more prematurely than the comparison group (32 weeks v 38 weeks' gestation). Length of ventilatory support and requirement for ECMO were equivalent in the fetal surgery group and the postnatally treated comparison group. Length of hospital stay and hospital charges did not differ between the groups.

CONCLUSIONS

Open fetal surgery is physiologically sound and technically feasible, but does not improve survival over standard postnatal treatment in the subgroup of CDH fetuses without liver herniation, primarily because overall survival in this subgroup is favorable with or without prenatal intervention. These data suggest that fetuses who have prenatally diagnosed CDH and without evidence of liver herniation should be treated postnatally.

Anesthesia for combined cesarean section and extra-adrenal pheochromocytoma resection: a case report and literature review

Pheochromocytoma during pregnancy is unusual, with approximately 250 cases now reported in the literature. The current case describes the anesthetic management of a patient with a large extra-adrenal pheochromocytoma who underwent a combined cesarean section and tumor removal in which perioperative hemodynamic control was difficult despite high-dose a-adrenergic blockade. In this case it is believed that difficulty in perioperative hemodynamic management was related to mechanical stimulation of the tumor by the gravid uterus. Review of published case reports since 1980 reveals that a pheochromocytoma during pregnancy may be diagnosed in an extra-adrenal location relatively more commonly compared to non-pregnant patients. Established criteria exist for the adequacy of alpha- and beta-adrebergic blockade for the management of pheochromocytoma in the non-pregnant patient. We discuss how these criteria apply to pregnant patients with pheochromocytoma, and suggest possible modifications to the criteria.

Operating on placental support: the ex utero intrapartum treatment procedure

While treating eight fetuses with predictable airway obstruction, the authors developed a systematic approach, the ex utero intrapartum treatment procedure, to secure the airway during delivery. Six patients had their trachea plugged or clipped in utero for treatment of congenital diaphragmatic hernia, and two patients had prenatally diagnosed cystic hygroma of the neck and oropharynx. The ex utero intrapartum treatment procedure was performed by using high doses of inhaled halogenated agents to facilitate uterine relaxation during cesarean section, securing the fetal airway while feto-placental circulation remained intact, and then dividing the umbilical cord. A variety of procedures were performed during the ex utero intrapartum treatment procedure including bronchoscopy, orotracheal intubation, tracheostomy, tracheostomy with retrograde orotracheal intubation, tracheoplasty, removal of internal tracheal plug, removal of external tracheal clip, central line placement, and instillation of surfactant. There were minimal maternal or fetal complications during the procedure. This approach requires the coordinated efforts of pediatric surgeons, obstetricians, anesthesiologists, sonographers, and neonatologists. The combination of intensive maternal-fetal monitoring, cesarean section with maximal uterine relaxation, and maintenance of intact feto-placental circulation provides a controlled environment for securing the airway in babies with prenatally diagnosed airway obstruction.

Correction of congenital diaphragmatic hernia in utero VIII: Response of the hypoplastic lung to tracheal occlusion

Most fetuses with congenital diaphragmatic hernia (CDH) diagnosed before 24 weeks' gestation die despite optimal postnatal care. In fetuses with liver herniation into the chest, prenatal repair has not been successful. In the course of exploring the pathophysiology of CDH and its repair in fetal lambs, the authors found that obstructing the normal egress of fetal lung fluid enlarges developing fetal lungs, reduces the herniated viscera, and accelerates lung growth, resulting in improved pulmonary function after birth. They developed and tested experimentally a variety of methods to temporarily occlude the fetal trachea, allow fetal lung growth, and reverse the obstruction at birth. The authors applied this strategy of temporary tracheal occlusion in eight human fetuses with CDH and liver herniation at 25 to 28 weeks' gestation. With ongoing experimental and clinical experience, the technique of tracheal occlusion evolved from an internal plug (two patients) to an external clip (six patients), and a technique was developed for unplugging the trachea at the time of birth (Ex Utero Intrapartum Tracheoplasty [EXIT]). Two fetuses had a foam plug placed inside the trachea. The first showed dramatic lung growth in utero and survived; the second (who had a smaller plug to avoid tracheomalacia) showed no demonstrable lung growth and died at birth. Two fetuses had external spring-loaded aneurysm clips placed on the trachea; one was aborted due to tocolytic failure, and the other showed no lung growth (presumed leak) and died 3 months after birth. Four fetuses had metal clips placed on the trachea. All showed dramatic lung growth in utero, with reversal of pulmonary hypoplasia documented after birth. However, all died of nonpulmonary causes. Temporary occlusion of the fetal trachea accelerates fetal lung growth and ameliorates the often fatal pulmonary hypoplasia associated with severe CDH. Although the strategy is physiologically sound and technically feasible, complications encountered during the evolution of these techniques have limited the survival rate. Further evolution of this technique is required before it can be recommended as therapy for fetal pulmonary hypoplasia.

Management of combined renal and pancreatic trauma

During a 15-year period we treated 38 patients with combined renal and pancreatic injuries (40 kidneys): 18 patients (19 kidneys) with renal contusion (89% from blunt trauma) and 20 with renal laceration or vascular injuries (90% from penetrating trauma). All patients with renal contusion were managed conservatively without complication, despite major pancreatic injury in a third. The 16 patients with significant renal and pancreatic injuries were classified as a high risk group: 3 underwent nephrectomy for vascular injuries that could not be repaired but all of the remaining kidneys were salvaged. Perinephric abscesses developed in 2 of these patients, for a major complication rate of 15%. No secondary nephrectomies were necessary, nor did urinary fistulas develop. We conclude that significant renal injuries in patients with major pancreatic injuries may be managed by renal repair with an increased but acceptable complication rate and that nephrectomy should be performed only if the degree of renal injury precludes repair.

Transitional cell carcinoma of fossa navicularis in a man with three other synchronous malignancies

Transitional cell carcinoma arising from the anterior portion of the male urethra is rare, with less than 10 cases reported in the literature. Our patient had a high-grade, highly invasive transitional cell carcinoma originating in the fossa navicularis and extending proximally along the corpus spongiosum, the corpora cavernosa, and blood and lymphatic vessels. In addition, the patient had a concurrent low-grade prostatic adenocarcinoma, a large basal cell carcinoma of the nose, and a squamous cell carcinoma of the penile skin. The previously reported cases are reviewed, with particular reference to the possible association of these tumors with human papillomavirus infection.

Subarachnoid morphine and fentanyl for labor analgesia. Efficacy and adverse effects

BACKGROUND AND OBJECTIVES

The study was designed to compare analgesic efficacy and associated adverse effects between a group of parturients receiving subarachnoid opioids via the combined spinal-epidural (CSE) technique with a group receiving epidural analgesia alone for labor.

METHODS

The authors studied 59 healthy parturients admitted for labor and delivery. Group 1 consisted of 26 consecutive patients who received the CSE technique, initially receiving subarachnoid morphine sulfate 0.25 mg, and fentanyl 25 micrograms, for labor analgesia. If patients requested additional analgesia, epidural analgesia was initiated. Group 2 was comprised of 33 consecutive patients who received conventional epidural analgesia. All patients were monitored for the occurrence and treatment of peripartum nausea and vomiting (N/V), pruritus, postdural puncture headache, and respiratory depression.

RESULTS

Additional analgesia was requested by 20/26 (76%) patients in group 1. Group 1 reported more N/V (50% versus 15%, P = .01) and required more therapy for N/V (31% versus 0%, P < .01) than group 2. Furthermore, group 1 reported having more pruritus (50% versus 3%, P < .01), and required more treatment for pruritus (35% versus 3%, P < .01), than group 2. No patient developed significant respiratory depression. Only one patient in group 1 developed a postdural puncture headache, following unintentional dural puncture with the 18 gauge Tuohy needle.

CONCLUSIONS

The combination of subarachnoid morphine 0.25 mg and fentanyl 25 micrograms, when used for labor analgesia as part of the CSE technique, was associated with a higher incidence of clinically significant nausea and vomiting and pruritus, compared to conventional epidural anesthesia. Furthermore, the combination of subarachnoid morphine and fentanyl proved ineffective in providing adequate pain relief for the duration of labor and delivery for the majority of patients. The authors recommend that subarachnoid morphine and fentanyl serve a limited role in the treatment of labor pain.

Current indications for cutaneous ureterostomy

OBJECTIVE

To assess the current indications for cutaneous ureterostomy in children.

METHOD

A total of 32 children underwent cutaneous ureterostomy at Texas Children's Hospital from 1975 to 1990. Medical records were reviewed to determine the urologic diagnosis, the indication for urinary diversion, the type of ureterostomy performed, and the outcome for each patient.

RESULTS

Twenty patients underwent loop cutaneous ureterostomy (LCU) or pyelostomy and 12 patients underwent end cutaneous ureterostomy (ECU). The main indication for LCU was obstructive uropathy unresponsive to lower urinary tract drainage, and the most common cause was posterior urethral valves. Other indications for LCU included obstruction requiring delayed surgical correction, high-grade reflux into a solitary kidney, and obstruction with infection. The children who required ECU were an older, more diverse group than those who underwent LCU. The main indication for ECU was poor bladder function secondary to a variety of congenital anomalies, including prune-belly syndrome, posterior urethral valves, bladder exstrophy, and urogenital sinus defect.

CONCLUSION

LCU is easy to perform and is an excellent method for achieving temporary upper urinary tract drainage. ECU is suited for long-term or permanent urinary diversion in children with at least one dilated ureter, and can provide a socially acceptable stoma when delayed reconstruction is necessary. Many children who were "permanently" diverted by ECU may be undiverted using newer reconstructive techniques.

Conformational differences between bulged pyrimidines (C-C) and purines (A-A, I-I) at the branch point of three-stranded DNA junctions

We have synthesized DNA oligomers that can combine to form three-way junctions containing six base pairs in each stem and two unpaired bases at the branch point. Gel electrophoresis experiments indicate that the oligomers form stable complexes with equimolar stoichiometry. Using two- and three-dimensional proton nuclear magnetic resonance spectroscopy, we have completed nonexchangeable proton chemical shift assignments for three junctions which differ only in the identity of the unpaired bases (C-C, A-A, or I-I) at the branch point. Our results indicate that unpaired pyrimidines at the branch point of junctions behave differently than do unpaired purines. In a junction with two unpaired cytidines, the 5' base loops out from the molecule to lie along the minor groove of the preceding duplex stem of the junction. The 3' unpaired cytidine also demonstrates an unusual pattern of NOE connectivities with detected cross peaks to the subsequent base in the 3' direction. Junctions with unpaired purines at the branch point exhibit different behavior. Our data suggests that in these molecules the unpaired bases participate in stacking interactions among themselves and with the neighboring bases in the molecule. Despite these differences, the NOE patterns from each junction suggest the presence of a preferred, pair-wise stacking between two of the helices within the molecule. The structural differences between bulge-pyrimidine and bulge-purine junctions are discussed in light of the functional significance unpaired bases might have in the structure and dynamics of multistranded DNA junctions and, by extension, to junctions within cellular RNAs.

Structural features of a three-stranded DNA junction containing a C-C junctional bulge

We have examined the stability of junctional base pairs in a three-way DNA junction with two unpaired cytidine residues at the branch point using two-dimensional nuclear Overhauser effect spectroscopy in H2O solution. Our data directly support the presence of two of the three junctional Watson-Crick base pairs, with indirect support for the third as well. These results complement the data presented in the preceding paper, where we examined the nonexchangeable proton resonance assignments of three-way DNA junctions from NOESY data in D2O solution. We have incorporated the NOE data from both sets of experiments, using this information as input for a combined distance geometry (DG) and simulated annealing (SA) protocol designed to derive three-dimensional structures of the junction molecule consistent with the NMR data. Although the data does not allow us to derive a unique solution for the structure of the molecule, certain conformational features are invariably present in our models. We demonstrate the existence of a preferred, pair-wise stacking arrangement between two of the three helices in the junction. Furthermore, the remaining duplex stem is situated so that it always forms an acute angle with just one of the arms from the quasi-continuous helix. The unpaired residues provide an extended backbone segment linking two of the helices together. The first unpaired base on the 5' end loops out from the interior of the molecule to reside along the minor groove of one helix. The second is located within the interior of the molecule, stacking below one of the junctional base pairs. Our findings suggest that junctional base pair stacking is an important determinant in the conformation of multistranded nucleic acid junctions. In three-way junctions, the presence of unpaired bases at the branch point provides a relief from covalent constraints that would otherwise prevent the simultaneous realization of both base pairing and base pair stacking within the branch point of the molecule.

Effects of propofol and thiopental on maternal and fetal cardiovascular and acid-base variables in the pregnant ewe

BACKGROUND

The effects of propofol on uterine blood flow are not understood well. This is a relatively new agent that is finding increased use for nonobstetric surgical procedures during pregnancy and induction of anesthesia for cesarean section.

METHODS

The effects of induction and maintenance of anesthesia with propofol were studied on maternal and fetal cardiovascular and acid-base variables in a chronically instrumented pregnant sheep model. Anesthesia was induced with a 2 mg/kg bolus of propofol and maintained with of one of three continuous infusions: 150, 300, and 450 micrograms.kg-1 x min-1. The control group received thiopental for induction, and anesthesia was maintained with isoflurane.

RESULTS

The use of propofol did not adversely affect maternal or fetal mean arterial pressure, heart rate, or base excess, fetal heart rate variability, or uterine blood flow. Uterine blood flow transiently decreased during induction and intubation with thiopental but remained stable during induction with propofol. However, administration of succinylcholine for intubation in the presence of propofol resulted in a transient, but severe, maternal bradycardia. Continuous infusion of 300 micrograms.kg-1.min-1 of propofol appeared to provide satisfactory anesthesia in the ewe.

CONCLUSIONS

Assuming the applicability of ovine data to humans, these findings suggest that induction and maintenance of anesthesia with propofol and 50% nitrous oxide in oxygen has no adverse fetal effects but warrants caution because of the potential risk of severe maternal bradycardia during induction of anesthesia using the combination of propofol and succinylcholine.

A comparison of patellar tendon autograft and allograft used for anterior cruciate ligament reconstruction in the goat model

Similar-sized patellar tendon autografts and fresh-frozen allografts were used to reconstruct the anterior cruciate ligament of one knee in 40 female goats. Evaluations of the reconstructions and contralateral controls at the 6-week and 6-month postoperative periods included anterior-posterior translation, mechanical properties determined during tensile failure tests, measurement of cross-sectional area, histology, collagen fibril size and area distribution, and associated articular cartilage degenerative changes. Six months after anterior cruciate ligament reconstruction, the autografts demonstrated a smaller increase in anterior-posterior displacement, values of maximum force to failure two times greater, a significant increase in cross-sectional area, a more rapid loss of large-diameter collagen fibrils, and an increased density and number of small-diameter collagen fibrils compared to the allografts. Clinical significance. More surgeons are allowing their patients to return to running and sports 6 months after anterior cruciate ligament reconstruction. While the structural and material properties of autografts and allografts at time zero are similar, in the goat model during the first 6 months they differ. The allografts demonstrate a greater decrease in their implantation structural properties, a slower rate of biologic incorporation, and the prolonged presence of an inflammatory response. At 6 months the autograft demonstrates a more robust biologic response, improved stability, and increased strength to failure values.

Frequency and location of extracapsular extension and positive surgical margins in radical prostatectomy specimens

Positive surgical margins have been reported with disturbing frequency in radical prostatectomy specimens and may portend an increased risk of eventual treatment failure. We determined the location of any cancer, extracapsular extension and positive surgical margins in 144 consecutive step-sectioned radical prostatectomy specimens. Of the 46 stage A cancer patients 98% had residual cancer in the prostate after transurethral resection and in 76% cancer was found posteriorly in the gland. Extracapsular extension was identified in 10 patients (22%): anteriorly in 5, posterolaterally in 5 and on the most apical transverse section in 4. Positive margins were found in 10 patients (22%) and half of these occurred posterolaterally. Of the 98 stage B cancer patients tumor was located posteriorly in 97%. Extracapsular extension was found in 62 patients (63%) and in 87% of these it was located posterolaterally. Positive margins were found in 23%, most commonly in the posterolateral and rectal areas (57% and 26%, respectively), and in more than half of these the positive margin resulted from incision into the capsule. In 18 of the 144 patients (13%) a single positive surgical margin was the only pathological indicator of treatment failure and half of these occurred in the area of the neurovascular bundle. Some of these patients with extraprostatic tumor might have been cured if wide excision of the neurovascular bundle had been performed. Overemphasis on preservation of potency during radical prostatectomy may leave some patients with persistent local disease.

Solution structure of a trinucleotide A-T-A bulge loop within a DNA duplex

We have synthesized an oligodeoxynucleotide duplex, d(G-C-A-T-C-G-A-T-A-G-C-T-A-C-G).d(C-G-T-A-G-C-C-G-A-T-C-G), with a three-base bulge loop (A-T-A) at a central site in the first strand. Nuclear Overhauser experiments (NOESY) in H2O indicate that the GC base pairs flanking the bulge loop are intact between 0 and 25 degrees C. Nuclear Overhauser effects in both H2O and D2O indicate that all bases within the bulge loop are stacked into the helix. These unpaired bases retain an anti conformation about their glycosidic bonds as they stack within the duplex. The absence of normal sequential connectivities between the two cytosine residues flanking the bulge site on the opposite strand indicates a disruption in the geometry of this base step upon insertion of the bulged bases into the helix. This conformational perturbation is more akin to a shearing apart of the bases, which laterally separates the two halves of the molecule, rather than the "wedge" model often invoked for single-base bulges. Using molecular dynamics calculations, with both NOE-derived proton-proton distances and relaxation matrix-calculated NOESY cross peak volumes as restraints, we have determined the solution structure of an A-T-A bulge loop within a DNA duplex. The bulged bases are stacked among themselves and with the guanine bases on either side of the loop. All three of the bulged bases are displaced by 2-3 A into the major groove, increasing the solvent accessibility of these residues. The ATA-bulge duplex is significantly kinked at the site of the lesion, in agreement with previously reported electron microscopy and gel retardation studies on bulge-containing duplexes [Hsieh, C.-H., & Griffith, J. D. (1989) Proc. Natl. Acad. Sci. U.S.A 86, 4833-4837; Bhattacharyya, A., & Lilley, D. M. J. (1989) Nucleic Acids Res. 17, 6821-6840]. Bending occurs in a direction away from the bulge-containing strand, and we find a significant twist difference of 84 degrees between the two base pairs flanking the bulge loop site. This value represents 58% of the twist difference for base pairs four steps apart in B-DNA. These results suggest a structural mechanism for the bending of DNA induced by unpaired bases, as well as accounting for the effect bulge loops may have on the secondary and tertiary structures of nucleic acids.

Comparative NMR study of A(n)-bulge loops in DNA duplexes: intrahelical stacking of A, A-A, and A-A-A bulge loops

We have prepared a series of deoxyoligonucleotide duplexes of the sequence d(G-C-A-T-C-G-X-G-C-T-A-C-G).d(C-G-T-A-G-C-C-G-A-T-G-C), in which X represents either one (A), two (A-A), or three (A-A-A) unpaired adenine basis. Using two-dimensional proton and phosphorus NMR spectroscopy, we have characterized conformational features of these bulge-loop duplexes in solution. We find that Watson-Crick hydrogen bonding is intact for all 12 base pairs, including the GC bases that flank the bulge loop. Observation of NOE connectivities in both H2O and D2O allows us to unambiguously localize all of the bulged adenine residues to intrahelical positions within the duplex. This is in contrast to an earlier model for multiple-base bulge loops in DNA [Bhattacharyya, A., & Lilley, D. M. J. (1989) Nucleic Acids Res. 17, 6821-6840], in which all but the most 5' bulged base are looped out into solution. We find that insertion of two or three bases into the duplex results in the disruption of specific sequential NOEs for the base step across from the bulge loop site on the opposite strand. This disruption is characterized by a partial shearing apart of these bases, such that certain sequential NOEs for this base step are preserved. We observe a downfield-shifted phosphorus resonance, which we assign in the A-A-A bulge duplex to the 3' side of the last bulged adenine residue. Proton and phosphorus chemical shift trends within the An-bulge duplex series indicate that there is an additive effect on the structural perturbations caused by additional unpaired bases within the bulge loop. This finding parallels previous observations [Bhattacharyya, A., & Lilley, D. M. J. (1989) Nucleic Acids Res. 17, 6821-6840; Hsieh, C.-H., & Griffith, J. D. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 4833-4837] on the magnitude of the induced bending of DNA duplexes by multiple-base bulge loops.

Hydralazine does not restore uterine blood flow during cocaine-induced hypertension in the pregnant ewe

Cocaine abuse is widespread, and its use by the parturient has potential significant adverse effects in both the mother and the newborn. This study was undertaken in gravid ewes to determine the effects of treatment of cocaine-induced hypertension with hydralazine (Apresoline) on the maternal and fetal cardiovascular systems, catecholamine response, blood gas and acid-base status, and uterine blood flow (UBF). Twenty-one experiments were performed in 15 chronically instrumented ewes near term gestation. After a 30-min control period, cocaine was given intravenously to all ewes for 55 min to induce and maintain increased maternal mean arterial pressure (MMAP) and reduced UBF. The sheep were randomly assigned to receive either cocaine alone (n = 11, control group) or hydralazine (n = 10, treatment group), starting 15 min after the cocaine administration. Both drugs were discontinued 55 min after the start of the cocaine administration, followed by a 35-min recovery period. In the control group, cocaine administration resulted in a 31 +/- 13% (SD) increase in MMAP (P less than 0.05) and a 26 +/- 21% reduction in UBF (P less than 0.05). In the treatment group, the initial cocaine administration resulted in a similar increase in MMAP and decrease in UBF. Hydralazine therapy restored MMAP toward baseline after 20 min of administration, but UBF remained reduced (37 +/- 17%) throughout therapy (P less than 0.05) and recovery (18 +/- 13%) (P less than 0.05). The maternal heart rate increased maximally by 121 +/- 33% (P less than 0.05) after the administration of hydralazine, compared with a 14 +/- 21% increase (P less than 0.05) in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy of continuous passive motion in the rehabilitation of anterior cruciate ligament reconstructions

Seventy-five patients undergoing arthroscopically-assisted anterior cruciate ligament reconstruction by the same surgeon were divided into three random subgroups. All of the anterior cruciate ligament reconstructions used the middle third of the ipsilateral patellar tendon autograft. Patients undergoing meniscal repair, extraarticular procedures, or repair of other ligaments were excluded. The 75 patients were divided into subgroups to assess the benefits or disadvantages of early active motion (25 patients), continuous passive motion (25 patients), and a combination of both (25 patients) during the first 30 days after surgery. All patients were evaluated at specific intervals for 6 months after surgery. Data recorded included drain output, medication usage, tourniquet time, leg involved, hospital stay length, KT-1000 testing (before surgery in the anesthetized patient, after the procedure was completed, and 2 and 6 months after surgery), and range of motion. Radiographs and the International Knee Evaluation Form were also used to evaluate the results. No statistically significant differences were found between the three groups. Side-to-side anterior-posterior differences, stability, and restoration of full range of motion were similar in each subgroup at each evaluated interval. In this prospective study of motion, started immediately after anterior cruciate ligament reconstruction, passive and active methods were shown to have identical results. A supervised active and passive motion program during the 1st month had the same results as either one used individually.