A real-time contouring feedback tool for consensus-based contour training

Purpose

Variability in contouring structures of interest for radiotherapy continues to be challenging. Although training can reduce such variability, having radiation oncologists provide feedback can be impractical. We developed a contour training tool to provide real-time feedback to trainees, thereby reducing variability in contouring.

Methods

We developed a novel metric termed localized signed square distance (LSSD) to provide feedback to the trainee on how their contour compares with a reference contour, which is generated real-time by combining trainee contour and multiple expert radiation oncologist contours. Nine trainees performed contour training by using six randomly assigned training cases that included one test case of the heart and left ventricle (LV). The test case was repeated 30 days later to assess retention. The distribution of LSSD maps of the initial contour for the training cases was combined and compared with the distribution of LSSD maps of the final contours for all training cases. The difference in standard deviations from the initial to final LSSD maps, ΔLSSD, was computed both on a per-case basis and for the entire group.

Results

For every training case, statistically significant ΔLSSD were observed for both the heart and LV. When all initial and final LSSD maps were aggregated for the training cases, before training, the mean LSSD ([range], standard deviation) was -0.8 mm ([-37.9, 34.9], 4.2) and 0.3 mm ([-25.1, 32.7], 4.8) for heart and LV, respectively. These were reduced to -0.1 mm ([-16.2, 7.3], 0.8) and 0.1 mm ([-6.6, 8.3], 0.7) for the final LSSD maps during the contour training sessions. For the retention case, the initial and final LSSD maps of the retention case were aggregated and were -1.5 mm ([-22.9, 19.9], 3.4) and -0.2 mm ([-4.5, 1.5], 0.7) for the heart and 1.8 mm ([-16.7, 34.5], 5.1) and 0.2 mm ([-3.9, 1.6],0.7) for the LV.

Conclusions

A tool that uses real-time contouring feedback was developed and successfully used for contour training of nine trainees. In all cases, the utility was able to guide the trainee and ultimately reduce the variability of the trainee's contouring.

Implementation of a stereotactic body radiotherapy program for unresectable pancreatic cancer in an integrated community academic radiation oncology satellite network

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PDSA methodology was used to implement a pancreas SBRT in an academic satellite network.

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Oncologic outcomes were favorable with no serious adverse events.

•

This technical note provides groundwork for safe establishment of SBRT pancreas programs.

With increasing interest in stereotactic body radiotherapy (SBRT) for unresectable pancreatic cancer, quality improvement (QI) initiatives to develop integrated clinical workflows are crucial to ensure quality assurance (QA) when introducing this challenging technique into radiation practices.

Materials/Methods: In 2017, we used the Plan, Do, Study, Act (PDSA) QI methodology to implement a new pancreas SBRT program in an integrated community radiation oncology satellite. A unified integrated information technology infrastructure was used to virtually integrate the planned workflow into the community radiation oncology satellite network (P – Plan/D – Do). This workflow included multiple prospective quality assurance (QA) measures including multidisciplinary evaluation, prospective scrutiny of radiation target delineation, prospective radiation plan evaluation, and monitoring of patient outcomes. Institutional review board approval was obtained to retrospectively study and report outcomes of patients treated in this program (S – Study).

Results:

There were 12 consecutive patients identified who were treated in this program from 2017 to 2020 with a median follow-up of 27 months. The median survival was 13 months, median local failure free survival was 12 months and median progression free survival was 6 months from SBRT. There were no acute or late Common Terminology Criteria for Adverse Effects (CTCAE) version 5 toxicities ≥ Grade 3.

Conclusion:

We report the successful implementation of a community pancreas SBRT program involving multiple prospective QA measures, providing the groundwork to safely expand access to pancreas SBRT in our community satellite network (A – Act).

Urinary B-cell-activating factor of the tumour necrosis factor family (BAFF) in systemic lupus erythematosus

INTRODUCTION

We examined the clinical relevance of urinary concentrations of B-cell-activating factor of the tumour necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) in systemic lupus erythematosus (SLE).

METHODS

We quantified urinary BAFF (uBAFF) by enzyme-linked immunosorbent assay in 85 SLE, 28 primary Sjögren syndrome (pSS), 40 immunoglobulin A nephropathy (IgAN) patients and 36 healthy controls (HCs). Urinary APRIL (uAPRIL) and monocyte chemoattractant protein 1 (uMCP-1) were also quantified. Overall and renal SLE disease activity were assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000.

RESULTS

uBAFF was detected in 12% (10/85) of SLE patients, but was undetectable in HCs, IgAN and pSS patients. uBAFF was detectable in 28% (5/18) of SLE patients with active nephritis vs 5/67 (7%) of those without ( p = 0.03), and uBAFF was significantly higher in active renal patients ( p = 0.02) and more likely to be detected in patients with persistently active renal disease. In comparison, uAPRIL and uMCP-1 were detected in 32% (25/77) and 46% (22/48) of SLE patients, respectively. While no difference in proportion of samples with detectable uAPRIL was observed between SLE, HCs and IgAN patients, both uAPRIL and uMCP-1 were significantly detectable in higher proportions of patients with active renal disease.

CONCLUSIONS

uBAFF was detectable in a small but a significant proportion of SLE patients but not in other groups tested, and was higher in SLE patients with active renal disease.

Prospective Comparison of Toxicity and Cosmetic Outcome After Accelerated Partial Breast Irradiation With Conformal External Beam Radiotherapy or Single-Entry Multilumen Intracavitary Brachytherapy

PURPOSE

This study aimed to prospectively characterize toxicity and cosmesis after accelerated partial breast irradiation (APBI) with 3-dimensional conformal radiation therapy (CRT) or single-entry, multilumen, intracavitary brachytherapy.

METHODS AND MATERIALS

A total of 281 patients with pTis, pT1N0, or pT2N0 (≤3.0 cm) breast cancer treated with segmental mastectomy were prospectively enrolled from December 2008 through August 2014. APBI was delivered using 3-dimensional CRT (n = 29) or with SAVI (n = 176), Contura (n = 56), or MammoSite (n = 20) brachytherapy catheters. Patients were evaluated at protocol-specified intervals, at which time the radiation oncologist scored cosmetic outcome, toxicities, and recurrence status using a standardized template.

RESULTS

The median follow-up time is 41 months. Grade 1 seroma and fibrosis were more common with brachytherapy than with 3-dimensional CRT (50.4% vs 3.4% for seroma; P < .0001 and 66.3% vs 44.8% for fibrosis; P = .02), but grade 1 edema was more common with 3-dimensional CRT than with brachytherapy (17.2% vs 5.6%; P = .04). Grade 2 to 3 pain was more common with 3-dimensional CRT (17.2% vs 5.2%; P = .03). Actuarial 5-year rates of fair or poor radiation oncologist-reported cosmetic outcome were 9% for 3-dimensional CRT and 24% for brachytherapy (P = .13). Brachytherapy was significantly associated with inferior cosmesis on mixed model analysis (P = .003). Significant predictors of reduced risk of adverse cosmetic outcome after brachytherapy were D0.1cc (skin) ≤102%, minimum skin distance >5.1 mm, dose homogeneity index >0.54, and volume of nonconformance ≤0.89 cc. The 5-year ipsilateral breast recurrence was 4.3% for brachytherapy and 4.2% for 3-dimensional CRT APBI patients (P = .95).

CONCLUSIONS

Brachytherapy APBI is associated with higher rates of grade 1 fibrosis and seroma than 3-dimensional CRT but lower rates of grade 1 edema and grade 2 to 3 pain than 3-dimensional CRT. Rates of radiation oncologist-reported fair or poor cosmetic outcomes are higher with brachytherapy. We identified dosimetric parameters that predict reduced risk of adverse cosmetic outcome after brachytherapy-based APBI. Ipsilateral breast recurrence was equivalent for brachytherapy and 3-dimensional CRT.

Abstract P2-11-12: Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy

Purpose/Objective(s):

To prospectively compare late toxicity after accelerated partial breast irradiation (APBI) with 3D-conformal external beam radiotherapy (3D-CRT) or single-entry multi-lumen intracavitary brachytherapy.

Patients/Methods:

Two hundred eighty-one patients with pTis or pT2N0 (≤3.0 cm) breast cancer treated with segmental mastectomy were prospectively enrolled on a multi-institution observational protocol from 12/2008 – 8/2014. Patients were enrolled and treated at primary, satellite, and affiliated academic institutions. APBI was delivered using 3D-CRT or with a Contura®, MammoSite®, or SAVI® brachytherapy catheter. 3D-CRT patients were treated to 34.0 Gy (7%) or 38.5 Gy (93%) at 3.4-3.85 Gy/fx BID and brachytherapy patients were treated to 34.0 Gy at 3.4 Gy/fx BID. Per protocol, patients were clinically evaluated at 2, 6, 12, 18, and 24 months and then annually. At each clinical evaluation the radiation oncologist scored cosmetic outcome (excellent/good/fair/poor according to the Harvard Cosmesis Scale), toxicity (seroma/infection/fat necrosis/pain/telangiectasia/radiation dermatitis/hyperpigmentation/hypopigmentation/fibrosis/induration/edema/other according to CTCAE v3.0) and recurrence status.

Results:

The median age was 61 years. Of 281 patients, 211 (75%) had invasive breast cancer and 70 (25%) had in situ disease. Among patients with invasive disease, 90% were HR+/HER2-, and among patients with in situ disease, 83% were HR+. APBI was delivered with 3D-CRT in 29 (10%) patients and with single-entry multi-lumen intracavitary brachytherapy in 252 (90%) patients. Among the brachytherapy patients, APBI was delivered with the SAVI®, Contura®, and MammoSite® devices in 176 (70%), 56 (22%), and 20 (8%) patients, respectively. With a median follow-up of 49 months, rates of Grade 1 (G1) and Grade 2-3 (G2-3) toxicity are:

 3D-CRTBrachytherapy   G1G2-3G1G2-3G1G2-3 N (%)N (%)N (%)N (%)  Fibrosis13 (46%)1 (4%)176 (72%)6 (2%)p=0.008p=0.54Fat Necrosis0 (0%)0 (0%)0 (0%)4 (2%)p=1.00p=1.00Telangiectasia6 (21%)1 (4%)44 (18%)5 (2%)p=0.61p=0.48Seroma2 (7%)1 (4%)135 (55%)12 (5%)p&lt;0.0001p=1.00

Mean skin dose of the maximally-irradiated 0.1 cc (D0.1cc) of skin was significantly higher in patients who developed telangiectasia (103.4% ± 16.1% compared to 96.5% ± 18.6% of prescription dose, p=0.007) and fibrosis (100.1% ± 15.5% compared to 92.8% ± 23.0% of prescription dose, p=0.02). Crude rates of fair or poor cosmetic outcome at 2-4 and 4-6 years were 6.9% and 14.8%, respectively, for 3D-CRT and 14.8% and 21.3%, respectively, for brachytherapy (p&gt;0.05 at both timepoints). Five-year recurrence-free survival was 96.3% with 3D-CRT and 96.1% for brachytherapy (p&gt;0.05).

Conclusion:

APBI with single-entry multi-lumen intracavitary brachytherapy is associated with increased rates of grade 1 fibrosis and seroma than APBI with 3D-CRT. Higher mean skin D0.1cc is associated with increased risk of telangiectasia and fibrosis. Despite increased low-grade fibrosis, there is no significant difference in radiation oncologist-reported fair or poor cosmetic outcome out to six years, or rate of five-year ipsilateral breast recurrence.

Citation Format: Stecklein SR, Babiera GV, Bedrosian I, Shaitelman SF, Ballo MT, Tereffe W, Arzu IY, Perkins GH, Strom EA, Reed VK, Dvorak T, Smith BD, Woodward WA, Hoffman KE, Schlembach PJ, Chronowski GM, Shah SJ, Kirsner SM, Nelson CL, Guerra W, Dibaj SS, Bloom ES. Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy [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 P2-11-12.

Lower mean heart dose with deep inspiration breath hold-whole breast irradiation compared with brachytherapy-based accelerated partial breast irradiation for women with left-sided tumors

PURPOSE

For left-sided breast cancer, radiation to the heart is a concern. We present a comparison of mean heart and coronary artery biologically effective dose (BED) between accelerated partial breast irradiation (APBI) and whole breast irradiation with deep inspiration breath-hold technique (DIBH-WBI).

METHODS AND MATERIALS

A total of 100 patients with left-sided, early-stage breast cancer were identified. Fifty underwent single-entry catheter-based APBI and 50 underwent DIBH-WBI. The heart, left anterior descending/interventricular branch, left main, and right coronary artery were delineated. BEDs were calculated from APBI treatment plans (34 Gy in 3.4 Gy twice daily fractions) and for 4 separate plans generated for each DIBH-WBI patient: 50 Gy in 25 fractions (50/25), 50/25 + 10/5 boost, 40/15, and 40/15 + 10/5 boost.

RESULTS

BED to the heart and coronary vessels were statistically significantly higher with APBI than with any of the DIBH-WBI dose/fractionation schedules.

CONCLUSIONS

For women with left-sided early-stage breast cancer, DIBH-WBI resulted in statistically significantly lower mean BED to the heart and coronary vessels compared with APBI. This is likely due to increased physical separation between the heart and tumor bed afforded by the DIBH-WBI technique. Long-term assessment of late effects in these tissues will be required to determine whether these differences are clinically significant.

Contralateral breast dose from partial breast brachytherapy

The purpose of this study was to determine the dose to the contralateral breast during accelerated partial breast irradiation (APBI) and to compare it to external beam‐published values. Thermoluminescent dosimeter (TLD) packets were used to measure the dose to the most medial aspect of the contralateral breast during APBI simulation, daily quality assurance (QA), and treatment. All patients in this study were treated with a single‐entry, multicatheter device for 10 fractions to a total dose of 34 Gy. A mark was placed on the patient's skin on the medial aspect of the opposite breast. Three TLD packets were taped to this mark during the pretreatment simulation. Simulations consisted of an AP and Lateral scout and a limited axial scan encompassing the lumpectomy cavity (miniscan), if rotation was a concern. After the simulation the TLD packets were removed and the patients were moved to the high‐dose‐rate (HDR) vault where three new TLD packets were taped onto the patients at the skin mark. Treatment was administered with a Nucletron HDR afterloader using Iridium‐192 as the treatment source. Post‐treatment, TLDs were read (along with the simulation and QA TLD and a set of standards exposed to a known dose of 6 MV photons). Measurements indicate an average total dose to the contralateral breast of 70 cGy for outer quadrant implants and 181 cGy for inner quadrant implants. Compared to external beam breast tangents, these results point to less dose being delivered to the contralateral breast when using APBI.

PACS number: 87.55.D‐

Commissioning results of an automated treatment planning verification system

A dose calculation verification system (VS) was acquired and commissioned as a second check on the treatment planning system (TPS). This system reads DICOM CT datasets, RT plans, RT structures, and RT dose from the TPS and automatically, using its own collapsed cone superposition/convolution algorithm, computes dose on the same CT dataset. The system was commissioned by extracting basic beam parameters for simple field geometries and dose verification for complex treatments. Percent depth doses (PDD) and profiles were extracted for field sizes using jaw settings 3 × 3 cm2 - 40 × 40 cm2 and compared to measured data, as well as our TPS model. Smaller fields of 1 × 1 cm2 and 2 × 2 cm2 generated using the multileaf collimator (MLC) were analyzed in the same fashion as the open fields. In addition, 40 patient plans consisting of both IMRT and VMAT were computed and the following comparisons were made: 1) TPS to the VS, 2) VS to measured data, and 3) TPS to measured data where measured data is both ion chamber (IC) and film measurements. Our results indicated for all field sizes using jaw settings PDD errors for the VS on average were less than 0.87%, 1.38%, and 1.07% for 6x, 15x, and 18x, respectively, relative to measured data. PDD errors for MLC field sizes were less than 2.28%, 1.02%, and 2.23% for 6x, 15x, and 18x, respectively. The infield profile analysis yielded results less than 0.58% for 6x, 0.61% for 15x, and 0.77% for 18x for the VS relative to measured data. Analysis of the penumbra region yields results ranging from 66.5% points, meeting the DTA criteria to 100% of the points for smaller field sizes for all energies. Analysis of profile data for field sizes generated using the MLC saw agreement with infield DTA analysis ranging from 68.8%-100% points passing the 1.5%/1.5 mm criteria. Results from the dose verification for IMRT and VMAT beams indicated that, on average, the ratio of TPS to IC and VS to IC measurements was 100.5 ± 1.9% and 100.4 ± 1.3%, respectively, while our TPS to VS was 100.1 ± 1.0%. When comparing the TPS and VS to film measurements, the average percentage pixels passing a 3%/3mm criteria based gamma analysis were 96.6 ± 4.2% and 97 ± 5.6%, respectively. When the VS was compared to the TPS, on average 98.1 ± 5.3% of pixels passed the gamma analysis. Based upon these preliminary results, the VS system should be able to calculate dose adequately as a verification tool of our TPS.

Behavioral sensitization to amphetamine is not accompanied by changes in glutamate receptor surface expression in the rat nucleus accumbens

We examined whether behavioral sensitization to amphetamine is associated with redistribution of glutamate receptors (GluR) in the rat nucleus accumbens (NAc) or dorsolateral striatum (DLSTR). Following repeated amphetamine treatment and 21 days of withdrawal, surface and intracellular levels of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) or NMDA receptor subunits were determined using a protein cross-linking assay. In contrast to our previous results in cocaine-sensitized rats, we did not observe redistribution of GluR1 or GluR2 to the cell surface in the NAc after amphetamine withdrawal, although a small increase in total GluR1 was found in the shell subregion. Nor did we observe activation of signaling pathways associated with cocaine-induced AMPA receptor trafficking or changes in NMDA receptor subunits. No significant changes were observed in the DLSTR. We also investigated the effect of administering a challenge injection of amphetamine to amphetamine-sensitized rats 24 h prior to biochemical analysis based on prior studies showing that cocaine challenge decreases AMPA receptor surface expression in the NAc of cocaine-sensitized rats. GluR1 and GluR2 were not significantly altered in either NAc or DLSTR, although a modest effect on GluR3 cannot be ruled out. Our results suggest that glutamate transmission in the NAc is dramatically different in rats sensitized to amphetamine versus cocaine.

Increased serum pigment epithelium-derived factor is associated with microvascular complications, vascular stiffness and inflammation in Type 1 diabetes

AIMS

To determine in Type 1 diabetes patients if levels of pigment epithelium-derived factor (PEDF), an anti-angiogenic, anti-inflammatory and antioxidant factor, are increased in individuals with complications and positively related to vascular and renal dysfunction, body mass index, glycated haemoglobin, lipids, inflammation and oxidative stress.

METHODS

Serum PEDF levels were measured by ELISA in a cross-sectional study of 123 Type 1 diabetic patients (71 without and 52 with microvascular complications) and 31 non-diabetic control subjects. PEDF associations with complication status, pulse-wave analysis and biochemical results were explored.

RESULTS

PEDF levels [geometric mean (95% CI)] were increased in patients with complications 8.2 (7.0-9.6) microg/ml, vs. complication-free patients [5.3 (4.7-6.0) microg/ml, P < 0.001] and control subjects [5.3 (4.6-6.1) microg/ml, P < 0.001; anova between three groups, P < 0.001], but did not differ significantly between control subjects and complication-free patients (P > 0.05). In diabetes, PEDF levels correlated (all P < 0.001) with systolic blood pressure (r = 0.317), pulse pressure (r = 0.337), small artery elasticity (r = -0.269), glycated haemoglobin (r = 0.245), body mass index (r = 0.362), renal dysfunction [including serum creatinine (r = 0.491), cystatin C (r = 0.500)], triglycerides (r = 0.367), and inflammation [including log(e)C-reactive protein (CRP; r = 0.329), and soluble vascular cell adhesion molecule-1 (r = 0.363)]. Age, blood urea nitrogen, systolic blood pressure, pulse pressure and log(e)CRP correlated with PEDF levels in control subjects (all P < 0.04). PEDF levels were not significantly correlated with measures of oxidative stress: isoprostanes, oxidized low-density lipoprotein or paraoxonase-1 activity. On stepwise linear regression analysis (all subjects), independent determinants of PEDF levels were renal function, triglycerides, inflammation, small artery elasticity and age (r(2) = 0.427).

CONCLUSIONS

In Type 1 diabetes, serum PEDF levels are associated with microvascular complications, poor vascular health, hyperglycaemia, adiposity and inflammation.

The laterodorsal tegmentum contributes to behavioral sensitization to amphetamine

A critical event in the development of behavioral sensitization is a transient increase in excitatory drive to dopamine neurons of the ventral tegmental area (VTA). This is likely to be due, in part, to the ability of drugs of abuse to produce long-term potentiation, expressed as increased AMPA receptor transmission, at excitatory synapses onto VTA dopamine neurons. We investigated the role of the laterodorsal tegmentum (LDT) in behavioral sensitization because LDT neurons provide an important source of excitatory drive to VTA dopamine neurons, through mixed glutamate and cholinergic inputs. To test the role of the LDT in amphetamine sensitization, ibotenic acid or sham lesions of the LDT were performed 1 week before the first of six daily amphetamine injections. When challenged with amphetamine 13 days after the last injection, sham rats expressed sensitization of stereotypy and post-stereotypy locomotor hyperactivity, whereas the latter was attenuated by ibotenic acid lesions of the LDT. To determine whether plasticity occurs in the LDT during amphetamine sensitization, we used a previously developed microdialysis assay in which increased ability of AMPA to activate a pathway serves as a marker for long-term potentiation. Two days after discontinuing repeated saline or amphetamine injections, the responsiveness of LDT-VTA neurons to AMPA was determined by microinjecting AMPA (0.4 nmol) into the LDT and measuring glutamate efflux in the ipsilateral VTA. Glutamate efflux was transiently increased in both groups but a delayed group difference was apparent with relatively higher glutamate efflux in amphetamine rats 30-60 min after AMPA injection. In parallel experiments, dopamine efflux in the nucleus accumbens (NAc) following intra-LDT AMPA declined in saline rats but remained relatively stable in amphetamine rats. Both results suggest relatively greater excitability of the LDT-VTA-NAc pathway after repeated amphetamine treatment. Our results provide the first evidence that neuronal plasticity in the LDT contributes to behavioral sensitization.

Prefrontal cortical modulation of acetylcholine release in posterior parietal cortex

Attentional processing is a crucial early stage in cognition and is subject to "top-down" regulation by prefrontal cortex (PFC). Top-down regulation involves modification of input processing in cortical and subcortical areas, including the posterior parietal cortex (PPC). Cortical cholinergic inputs, originating from the basal forebrain cholinergic system, have been demonstrated to mediate important aspects of attentional processing. The present study investigated the ability of cholinergic and glutamatergic transmission within PFC to regulate acetylcholine (ACh) release in PPC. The first set of experiments demonstrated increases in ACh efflux in PPC following AMPA administration into the PFC. These increases were antagonized by co-administration of the AMPA receptor antagonist DNQX into the PFC. The second set of experiments demonstrated that administration of carbachol, but not nicotine, into the PFC also increased ACh efflux in PPC. The effects of carbachol were attenuated by co-administration (into PFC) of a muscarinic antagonist (atropine) and partially attenuated by the nicotine antagonist mecamylamine and DNQX. Perfusion of carbachol, nicotine, or AMPA into the PPC did not affect PFC ACh efflux, suggesting that these cortical interactions are not bi-directional. These studies demonstrate the capacity of the PFC to regulate ACh release in the PPC via glutamatergic and cholinergic prefrontal mechanisms. Prefrontal regulation of ACh release elsewhere in the cortex is hypothesized to contribute to the cognitive optimization of input processing.

Murine Lung Tumor Measurement Using Respiratory-Gated Micro-Computed Tomography

OBJECTIVE

The authors explored micro-computed tomography (micro-CT) to quantify lung tumor number and volume in a specific genetic mouse model for lung cancer.

MATERIALS AND METHODS

The authors used K-ras mice, which develop lung adenomas and adenocarcinomas through somatic activation of the K-ras oncogene. Tumor number measured using micro-CT and were compared at necropsy (n = 38 mice). Tumor volume measurement precision (n = 39 mice) and accuracy (multiple tumors from a single mouse) were evaluated. Serial lung tumor volume was assessed in a pilot group (n = 8) of mice in vivo.

RESULTS

Tumor number assessed at necropsy and using micro-CT were significantly correlated. Lung tumor volume measurements were both reproducible (2% operator variability) and accurate (6% average error). Strikingly, we observed both tumor growth and shrinkage within individual mice.

CONCLUSION

Serial measurements provided evidence of tumor heterogeneity, an unexpected finding given the uniformity of the initiating genetic event. Micro-CT may become a powerful tool for murine lung cancer research in vivo.

Cortical cholinergic transmission and cortical information processing in schizophrenia

Models of the neuronal mediation of psychotic symptoms traditionally have focused on aberrations in the regulation of mesolimbic dopaminergic neurons, via their telencephalic afferent connections, and on the impact of abnormal mesolimbic activity for functions of the ventral striatum and its pallidal-thalamic-cortical efferent circuitry. Repeated psychostimulant exposure models major aspects of the sensitized activity of ventral striatal dopaminergic transmission that is observed in patients exhibiting psychotic symptoms. Based on neuroanatomical, neurochemical, and behavioral data, the hypothesis that an abnormally reactive cortical cholinergic input system represents a necessary correlate of a sensitized mesolimbic dopaminergic system is discussed. Moreover, the abnormal cognitive mechanisms that contribute to the development of psychotic symptoms are attributed specifically to the aberrations in cortical cholinergic transmission and to its consequences on the top-down regulation of sensory and sensory-associational input functions. Experimental evidence from studies demonstrating repeated amphetamine-induced sensitization of cortical cholinergic transmission and the ability of antipsychotic drugs to normalize the activity of cortical cholinergic inputs, and from experiments indicating the attentional consequences of manipulations that increase the excitability of cortical cholinergic inputs, supports this hypothesis. Relevant human neuropathological and psychopharmacological data are discussed, and the implications of an abnormally regulated cortical cholinergic input system for pharmacological treatment strategies are addressed. Given the role of cortical cholinergic inputs in gating cortical information processing, even subtle changes in the regulation of this cortexwide input system that represent a necessary transsynaptic consequence of sensitized mesolimbic dopaminergic transmission profoundly contribute to the neuronal mediation of psychotic symptoms.

Neurochemical correlates of sparing from motor deficits in rats depleted of striatal dopamine as weanlings

The behavioral and neurochemical effects of striatal DA depletions were investigated in rats lesioned as weanlings (Day 27) or as adults (250-300 g). Administration of 6-OHDA into the medial forebrain bundle resulted in comparably large (> or = 95%) depletions of tissue levels of DA in both age groups. As expected, rats depleted of DA as adults exhibited marked deficits in motoric behavior and body weight regulation that persisted for the 8 days of postsurgical observation. In contrast, rats depleted of DA as weanlings were spared from such deficits, and their behavior closely resembled that of age-matched controls. Microdialysis studies revealed dialysate levels of striatal DA that paralleled these age-dependent behavioral differences. At a time when age-related behavioral differences were still quite pronounced (5-6 days postsurgery), basal DA levels were reduced by 80% of control values in rats lesioned as adults whereas basal DA levels in rats lesioned as weanlings were unchanged relative to their controls. Finally, adults depleted of striatal DA as weanlings were no more sensitive to the movement-impairing effects of intrastriatal sulpiride (3.0 or 10.0 micrograms/hemisphere) infusions than were control rats. These data suggest that weanlings compensate for large, but incomplete, denervation of striatal DA with markedly enhanced release and turnover from residual terminals. This developmental plasticity may prevent the occurrence of behavioral deficits soon after the lesion and also the supersensitivity to the challenging effects of DA antagonists as animals grow into adulthood.

Sensitization of cortical acetylcholine release by repeated administration of nicotine in rats

RATIONALE

The integrity of cortical cholinergic transmission is vital to attentional processing. A growing literature suggests that alterations in attentional processing accompany addictive drug use. This study examined the effects of acute and repeated administration of nicotine on cortical acetylcholine release.

OBJECTIVES

The effects of repeated systemic nicotine administration on cortical acetylcholine (ACh) efflux in the frontal cortex were determined to test the hypothesis that repeated administration of nicotine results in a potentiated or sensitized increase in ACh efflux.

METHODS

Animals were injected with nicotine (0.4 mg/kg, i.p.) or vehicle twice daily for 4 days. Cortical ACh efflux was measured using repeated microdialysis sampling on four occasions: on day 1, during the first exposure to nicotine or vehicle, on day 5 during a final exposure to nicotine, on day 8 during a nicotine challenge, and again on day 10 following saline administration.

RESULTS

Acute nicotine administration on day 1 produced a 90% increase in cortical ACh efflux. Repeated exposure to nicotine resulted in a larger increase in cortical ACh efflux on day 5 (200%) and day 8 (210%) relative to ACh levels measured on day 1, and relative to animals that received vehicle during the initial treatment period. Cortical ACh efflux following acute nicotine administration was blocked by mecamylamine (1.0 mg/kg, i.p.). However, the sensitized efflux of cortical ACh on day 8 was only partially attenuated by mecamylamine (1.0 or 5.0 mg/kg, i.p.), suggesting a mecamylamine-insensitive component of the sensitized response to repeated nicotine administration.

CONCLUSIONS

Repeated administration of nicotine results in a sensitized increase in cortical ACh release. Sensitized cortical ACh release may mediate, in part, the cognitive components of nicotine addiction.

The best approach to safety is to fix schools and support children and staff

It is possible to create schools that are humane, caring places where discipline issues are minimized.

Effects of acute and repeated systemic administration of ketamine on prefrontal acetylcholine release and sustained attention performance in rats

RATIONALE

The effects of non-competitive N-methyl- D-aspartate (NMDA) receptor antagonists model aspects of schizophrenic symptomatology. Because effects on both cortical cholinergic transmission and attentional processes have been hypothesized to represent components of the properties of psychotogenic drugs, the present study investigated the effects of ketamine on the activity of cortical cholinergic inputs and attentional performance.

OBJECTIVE

To determine the effects of acute and repeated ketamine administration on cortical acetylcholine release and performance of rats in an operant task designed to assess sustained attention performance.

METHODS

Experiment 1 assessed the effects of ketamine (2.0-20.0 mg/kg, i.p.) on medial prefrontal acetylcholine release using in vivo microdialysis. In experiment 2, animals were pretreated with 2.0 mg/kg or 25.0 mg/kg ketamine for 7 days. Cortical acetylcholine release was assessed in these rats following the subsequent administration of a 'challenge' dose of 2.0 mg/kg on days 1, 8, and 15 following completion of the pretreatment regimen. Experiment 3 assessed the effects of acute ketamine administration (2.0, 4.0, and 8.0 mg/kg, i.p.) on sustained attention performance. In experiment 4, animals trained in the sustained attention task were pretreated with 25.0 mg/kg ketamine or vehicle for 7 days. In these animals, the performance effects of 2.0 mg/kg ketamine administered 1, 8, or 15 days after completion of the pretreatment regimen were assessed.

RESULTS

The acute administration of ketamine dose dependently increased cortical acetylcholine release by up to 250% above baseline and for over 40 min following the highest dose of ketamine. Pretreatment with 2.0 mg or 25.0 mg/kg did not robustly alter the effects of subsequent ketamine administration on cortical acetylcholine release. In animals performing the sustained attention task, administration of the highest dose of ketamine resulted in high levels of errors of omission, while the administration of the two smaller doses did not affect performance. Pretreatment with 25.0 mg/kg disrupted the attentional performance during the pretreatment period, but it did not affect the baseline performance thereafter. Furthermore, ketamine pretreatment did not systematically alter the performance effects of subsequent ketamine administration.

CONCLUSIONS

The robust stimulation of cortical acetylcholine release represents a potent component of the pharmacological effects of ketamine. The effects of acute ketamine on attentional performance were limited to high rates of omissions. Repeated ketamine administration 'sensitized' neither cortical acetylcholine release nor attentional performance. These effects of repeated ketamine differ substantially from those of another major psychotogenic drug, amphetamine, and thus support the view that ketamine and amphetamine model fundamentally different aspects of schizophrenia.

Staphylococcus aureus collagen adhesin contributes to the pathogenesis of osteomyelitis

To evaluate the role of the Staphylococcus aureus collagen-binding adhesin (Cna) in bone and joint infection, we generated a cna mutant in S. aureus UAMS-1, a strain that was originally isolated from the bone of a patient suffering from osteomyelitis. The mutant (UAMS-237) was unable to bind collagen but bound fibronectin at levels comparable to UAMS-1. The relative virulence of UAMS-1 and UAMS-237 was assessed using a murine model of acute hematogenous osteomyelitis. Specifically, 10(8) colony-forming units (cfu) were introduced into the bloodstream of NIH-Swiss mice via tail-vein injection. After 2 weeks, the left hind limb was harvested and examined histologically for evidence of osteomyelitis and septic arthritis. Osteomyelitis developed in 14 of 20 mice (70%) infected with UAMS-1, but only 1 of 20 (5%) infected with UAMS-237 (p < 0.001). In contrast, septic arthritis was observed in 12 of 20 mice (60%) infected with UAMS-1 and 14 of 20 (70%) infected with UAMS-237 (p < 0.75). These results indicate that Cna is not required to establish joint infection, but does make an important contribution to the ability of S. aureus to establish infection in bone through hematogenous spread.

Short-term results of the M2a-taper metal-on-metal articulation

A polyethylene-free, metal-on-metal acetabular system (M2a-taper [Biomet, Inc., Warsaw, IN]) was designed in an effort to improve total hip arthroplasty (THA) longevity. Minimum 2-year follow-up results involving 72 polyethylene liner THAs and 78 metal liner THAs from a multicenter, randomized, controlled, investigational device exemption study are reported. Mean Harris hip scores of 95.54 (polyethylene liner group) and 95.23 (metal liner group) were reported at mean follow-up intervals of 3.29 and 3.23 years. Radiographic evaluation revealed no evidence of early failure. No acetabular components have been revised or are pending revision. No statistically significant differences in the data were calculated between liner types except for the immediate postoperative (P=.0415) and minimum 2-year follow-up (P=.0341) angles of inclination. The M2a-taper metal-on-metal articulation may represent a viable alternative for THA in younger, higher demand patients.

Using observational data to estimate prognosis: an example using a coronary artery disease registry

With the proliferation of clinical data registries and the rising expense of clinical trials, observational data sources are increasingly providing evidence for clinical decision making. These data are viewed as complementary to randomized clinical trials (RCT). While not as rigorous a methodological design, observational studies yield important information about effectiveness of treatment, as compared with the efficacy results of RCTs. In addition, these studies often have the advantage of providing longer-term follow-up, beyond that of clinical trials. Hence, they are useful for assessing and comparing patients' long-term prognosis under different treatment strategies. For patients with coronary artery disease, many observational comparisons have focused on medical therapy versus interventional procedures. In addition to the well-studied problem of treatment selection bias (which is not the focus of the present study), three significant methodological problems must be addressed in the analysis of these data: (i) designation of the therapeutic arms in the presence of early deaths, withdrawals, and treatment cross-overs; (ii) identification of an equitable starting point for attributing survival time; (iii) site to site variability in short-term mortality. This paper discusses these issues and suggests strategies to deal with them. A proposed methodology is developed, applied and evaluated on a large observational database that has long-term follow-up on nearly 10 000 patients.

Assessing the clinical and economic burden of coronary artery disease: 1986-1998

BACKGROUND

The acute phase of coronary artery disease (CAD) is dramatic and receives much attention because of its high mortality and associated treatment cost. However, the acute phase typically resolves within 30 days whereas CAD is a chronic disease, which most patients will live with for more than a decade. We compared the clinical and economic burden of CAD during the acute phase (first 30 days) with that in the postacute phase (31st day through 10 years).

METHODS

We included acute coronary syndrome (ACS) patients with significant CAD receiving an initial cardiac catheterization at Duke University Medical Center between 1986 and 1997 with follow-up continuing through 1998. Inpatient medical costs were estimated from ACS clinical trial and economic study data. Costs were adjusted to 1997 values and discounted at 3% per annum.

RESULTS

Our study included 9,876 ACS patients (5,557 with an acute myocardial infarction [MI] and 4,319 with unstable angina [UA]). Acute MI patients had higher 30-day mortality than UA patients (5.6% vs. 2.3%, P <0.001). In addition, acute MI and UA patients had significant 10-year unadjusted and adjusted survival differences (both P <0.001). For patients who survived to 30 days, there was no difference in 10-year survival between acute MI and UA patients before adjustment (P = 0.472). After adjustment, however, unstable angina patients who survived to 30 days had greater survival than myocardial infarction patients (P = 0.011). Mean 10-year discounted ACS inpatient medical costs were $45,253 ($23,510 acute phase and $21,819 postacute phase, P = 0.002). Ten year costs for unstable angina patients were $46,423 ($21,824 acute phase and $24,599 postacute phase, P = 0.003); ten year costs for myocardial infarction patients were $44,663 ($24,823 acute phase and $19,840 postacute phase, P <0.001).

CONCLUSIONS

We found that the clinical and economic burden of CAD continues long after a patient's acute event has resolved and that postacute CAD cardiac event rates and inpatient medical costs may be higher than previously estimated. With much of all medical costs occurring in the postacute phase, the potential for effective secondary prevention therapies is substantial.

Behavioral approach to nondyskinetic dopamine antagonists: identification of seroquel

A great need exists for antipsychotic drugs which will not induce extrapyramidal symptoms (EPS) and tardive dyskinesias (TDs). These side effects are deemed to be a consequence of nonselective blockade of nigrostriatal and mesolimbic dopamine D2 receptors. Nondyskinetic clozapine (1) is a low-potency D2 dopamine receptor antagonist which appears to act selectively in the mesolimbic area. In this work dopamine antagonism was assessed in two mouse behavioral assays: antagonism of apomorphine-induced climbing and antagonism of apomorphine-induced disruption of swimming. The potential for the liability of dyskinesias was determined in haloperidol-sensitized Cebus monkeys. Initial examination of a few close cogeners of 1 enhanced confidence in the Cebus model as a predictor of dyskinetic potential. Considering dibenzazepines, 2 was not dyskinetic whereas 2a was dyskinetic. Among dibenzodiazepines, 1 did not induce dyskinesias whereas its N-2-(2-hydroxyethoxy)ethyl analogue 3 was dyskinetic. The emergence of such distinctions presented an opportunity. Thus, aromatic and N-substituted analogues of 6-(piperazin-1-yl)-11H-dibenz[b,e]azepines and 11-(piperazin-1-yl)dibenzo[b,f][1,4]thiazepines and -oxazepines were prepared and evaluated. 11-(4-[2-(2-Hydroxyethoxy)ethyl]piperazin-1-yl)dibenzo[b,f][1,4]thiazepine (23) was found to be an apomorphine antagonist comparable to clozapine. It was essentially nondyskinetic in the Cebus model. With 23 as a platform, a number of N-substituted analogues were found to be good apomorphine antagonists but all were dyskinetic.

Behavioral approach to nondyskinetic dopamine antagonists: identification of seroquel

A great need exists for antipsychotic drugs which will not induce extrapyramidal symptoms (EPS) and tardive dyskinesias (TDs). These side effects are deemed to be a consequence of nonselective blockade of nigrostriatal and mesolimbic dopamine D2 receptors. Nondyskinetic clozapine (1) is a low-potency D2 dopamine receptor antagonist which appears to act selectively in the mesolimbic area. In this work dopamine antagonism was assessed in two mouse behavioral assays: antagonism of apomorphine-induced climbing and antagonism of apomorphine-induced disruption of swimming. The potential for the liability of dyskinesias was determined in haloperidol-sensitized Cebus monkeys. Initial examination of a few close cogeners of 1 enhanced confidence in the Cebus model as a predictor of dyskinetic potential. Considering dibenzazepines, 2 was not dyskinetic whereas 2a was dyskinetic. Among dibenzodiazepines, 1 did not induce dyskinesias whereas its N-2-(2-hydroxyethoxy)ethyl analogue 3 was dyskinetic. The emergence of such distinctions presented an opportunity. Thus, aromatic and N-substituted analogues of 6-(piperazin-1-yl)-11H-dibenz[b,e]azepines and 11-(piperazin-1-yl)dibenzo[b,f][1,4]thiazepines and -oxazepines were prepared and evaluated. 11-(4-[2-(2-Hydroxyethoxy)ethyl]piperazin-1-yl)dibenzo[b,f][1,4]thiazepine (23) was found to be an apomorphine antagonist comparable to clozapine. It was essentially nondyskinetic in the Cebus model. With 23 as a platform, a number of N-substituted analogues were found to be good apomorphine antagonists but all were dyskinetic.

Treatment of osteonecrosis of the knee

There are several options for the treatment of patients with osteonecrosis about the knee. Three appear to be the most effective and include conservative treatment for small lesions without evidence of structural collapse, core decompression for relief of pain and possible delay in structural collapse in the patients with steroid-induced osteonecrosis, and either unicompartmental or total knee arthroplasty. Although other modalities have been reported, these three remain the most widely reported and generally offer the greatest success. With better recognition of these problems, longer duration follow-up, and larger patient series, the answers to the best treatment regimen will become better defined.

Repeated pretreatment with amphetamine sensitizes increases in cortical acetylcholine release

RATIONALE

Previous studies on the attentional effects of repeated psychostimulant administration in rats suggested the possibility that these effects are mediated via increases in the efficacy of psychostimulants to stimulate cortical acetylcholine (ACh) release. Furthermore, neurochemical data have raised the possibility that increases in nucleus accumbens (NAC) dopamine (DA) release trans-synaptically increase the excitability of basal forebrain corticopetal cholinergic projections, thereby supporting speculations about relationships between the effects of repeated psychostimulant administration on NAC DA and cortical ACh release.

OBJECTIVES

To determine whether repeated exposure to amphetamine would potentiate the stimulating effects of the drug on cortical ACh and NAC DA efflux.

METHODS

Rats were implanted with microdialysis guide cannula in the medial prefrontal cortex and the shell region of the ipsilateral NAC. Amphetamine (2.0 mg/kg i.p.) or saline (0.9%) was administered every other day for 10 days, for a total of five injections. ACh and DA efflux and locomotor activity were measured on the day of the first and last injections of this pretreatment regimen. All animals were retested following a challenge dose of amphetamine (2.0 mg/kg i.p.) given 10 and 19 days after the last pretreatment injection.

RESULTS

The initial injections of amphetamine stimulated ACh and DA efflux and locomotor behavior in both groups. The pretreatment with amphetamine potentiated the ability of the drug to stimulate cortical ACh efflux on day 19 of the withdrawal period. The pretreatment with amphetamine also increased the effects of the challenge dose on motoric activity on day 10. Pretreatment with amphetamine did not result in a significant augmentation of the amphetamine-induced increase in DA efflux in the NAC.

CONCLUSIONS

Pretreatment with amphetamine sensitizes the ability of amphetamine to stimulate cortical ACh efflux. These results support the hypothesis that sensitized release of cortical ACh mediated the previously observed hyperattentional impairments in amphetamine pretreated rats. Sensitized cortical ACh release following repeated exposure to psychostimulants may mediate the overprocessing of addictive drug-related stimuli, thus contributing to repeated compulsive addictive drug use.

Age-dependent neurobehavioral plasticity following forebrain dopamine depletions

The differential neurobehavioral effects of forebrain dopamine (DA) depletions in neonatal and adult rats are reviewed. In contrast to the severe and long-lasting parkinsonian sensorimotor deficits seen in rats sustaining large DA depletions as adults, rats comparably depleted as neonates are spared from these gross behavioral deficits. While DA released from residual striatal DA terminals remains necessary for the gradual recovery of sensorimotor function in rats lesioned as adults and the sparing from deficits in rats lesioned as neonates, the specific roles of D1- and D2-like receptors differ between the two age groups. Coactivation of striatal D1 and D2 receptors by residual DA is necessary for the expression of sensorimotor behavior in rats depleted of DA as adults (and in intact rats) whereas activation of either D1 or D2 receptors is sufficient for these behaviors in rats depleted of DA as neonates. We discuss the D1/D2 modulation of several important markers for striatal transmission (acetylcholine release from interneurons, induction of c-fos, and the expression of GAD65 mRNA in striatal efferents) as potential mechanisms underlying this striking age-dependent plasticity following forebrain DA depletions.

Systemic and intra-accumbens administration of amphetamine differentially affects cortical acetylcholine release

The present experiments tested the hypothesis that the amphetamine-induced increase in dopamine release in the nucleus accumbens represents a necessary and sufficient component of the ability of systemically administered amphetamine to stimulate cortical acetylcholine release. The effects of systemic or intra-accumbens administration of amphetamine on accumbens dopamine release and cortical acetylcholine release were assessed simultaneously in awake animals equipped with dialysis probes inserted into the shell of the nucleus accumbens and the medial prefrontal cortex. Additionally, the ability of intra-accumbens administration of dopamine D(1) and D(2) receptor antagonists to attenuate the effects of systemic amphetamine on cortical acetylcholine was tested. The effects of all treatments were assessed in interaction with a stimulus-induced activation of cortical acetylcholine release to account for the possibility that the demonstration of the trans-synaptic effects of accumbens dopamine requires pre-activation of basal forebrain circuits. Systemic amphetamine resulted in increases in basal cortical acetylcholine and accumbens dopamine efflux. Intra-accumbens administration of amphetamine substantially increased accumbens dopamine efflux, but did not significantly affect cortical acetylcholine efflux. Furthermore, intra-accumbens administration of sulpiride or SCH 23390 did not attenuate the systemic amphetamine-induced increase in cortical acetylcholine efflux. Collectively, the present data suggest that increases in accumbens dopamine release are neither sufficient nor necessary for the effects of systemically administered amphetamine on cortical acetylcholine release. The systemic amphetamine-induced increase in cortical acetylcholine may be mediated via multiple, parallel pathways and may not be attributable to a single afferent pathway of the basal forebrain.

Cost effectiveness of early discharge after uncomplicated acute myocardial infarction

BACKGROUND

Reducing the length of hospitalizations can reduce short-term costs, but there are few data on the long-term clinical and economic consequences of early discharge.

METHODS

Using data from the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) trial, we identified 22,361 patients with acute myocardial infarction who had an uncomplicated course for 72 hours after thrombolysis. Then, using a decision-analytic model, we examined the cost effectiveness of an additional day of hospitalization in this group. We defined incremental survival attributable to another day of monitored hospitalization, using Kaplan-Meier estimates to determine the rate of resuscitation after cardiac arrest between 72 and 96 hours. Lifetime survival curves for each group in the decision-analytic model were estimated from empirical one-year survival data from GUSTO-1. The costs of key hospital resources (e.g., room and monitoring) were derived from data in the GUSTO-1 cost-effectiveness analysis.

RESULTS

Of the patients with an uncomplicated course within 72 hours after thrombolysis, 16 had ventricular arrhythmias during the next 24 hours; 13 of these patients (81 percent) survived for at least 24 hours. On average, another 0.006 year of life per patient could be saved by keeping patients with an uncomplicated course in the hospital another day. At a cost of $624 for hospital and physicians' services, extending the hospital stay by another day would cost $105,629 per year of life saved. In sensitivity analyses, it was found that a fourth day of hospitalization would be economically attractive only if its cost could be reduced by more than 50 percent or if a high-risk subgroup could be identified in which the estimated survival benefit would be doubled.

CONCLUSIONS

Hospitalization of patients with uncomplicated myocardial infarction beyond three days after thrombolysis is economically unattractive by conventional standards.

Cost-effectiveness of platelet glycoprotein IIb/IIIa inhibition with eptifibatide in patients with non-ST-elevation acute coronary syndromes

BACKGROUND

In the PURSUIT trial, eptifibatide significantly reduced the 30-day incidence of death and myocardial infarction relative to placebo in 9461 patients with an acute coronary syndrome (unstable angina or non-Q-wave myocardial infarction).

METHODS AND RESULTS

We conducted a 2-part prospective economic substudy of the 3522 US patients enrolled in PURSUIT: (1) an empirical intention-to-treat comparison of medical costs (hospital plus physician) up to 6 months after hospitalization and (2) a lifetime cost-effectiveness analysis. The base-case cost-effectiveness ratio was expressed as the 1996 US dollars required to add 1 life-year with eptifibatide therapy. The 2 treatment arms had equivalent resource consumption and medical costs (exclusive of the cost of the eptifibatide regimen) during the index (enrollment) hospitalization (P=0.78) and up to 6 months afterward (P=0.60). The average wholesale price of the eptifibatide regimen was $1217, but a typical hospital discounted price was $1014. The estimated life expectancy from randomization in the US patients was 15.96 years for eptifibatide and 15.85 years for placebo, an incremental difference of 0.111. The incremental cost-effectiveness ratio for eptifibatide therapy in US PURSUIT patients was $16 491 per year of life saved. This result was robust through a wide range of sensitivity analyses. The cost-utility ratio for eptifibatide (using time trade-off defined utilities) was $19 693 per added quality-adjusted life-year.

CONCLUSIONS

Based on the results observed in the US PURSUIT patients, the routine addition of eptifibatide to standard care for non-ST-elevation acute coronary syndrome patients is economically attractive by conventional standards.

Primary and revision total hip replacement in patients who are Jehovah's Witnesses

The Jehovah's Witnesses do not accept allogeneic blood transfusion or certain types of autologous blood transfusion and, therefore, present the orthopaedic surgeon with a challenge in the management of perioperative blood loss. Accepting a patient who is a Jehovah's Witness as a surgical candidate requires the surgeon to be prepared medically to use known techniques to limit red blood cell loss or increase red blood cell mass, to resort to extraordinary means when necessary, and to be prepared philosophically to deal with catastrophic blood loss in a patient who may refuse even potentially life-saving transfusion. Issues pertinent to the management of intraoperative blood loss in the patient who is a Jehovah's Witness require careful delineation and specific treatment guidelines. The authors herein review their past and current experiences in the perioperative blood management of this patient population in an attempt to address this need.

Primary alveolar cleft bone grafting in unilateral cleft lip and palate: craniofacial form at age 8

Counterpart analysis can be advantageous for the clinician interested in the underlying determinants of the craniofacial form for any given person. This analysis was performed for a group of patients who underwent primary alveolar cleft bone grafting (N = 18) and a group of patients who did not undergo grafting (N = 19) who were 8 years of age (+/- 6 months). The primary grafting group more frequently noted maxillary retrusion, but of a nonsignificant magnitude. Also, the primary grafting group had greater mean magnitudes of mandibular opening as a compensatory adjustment in some patients, but this could not be generalized to all patients who had underdone primary grafting. The mean magnitude of craniofacial vertical shortening was also greater for some patients who had undergone primary grafting, but it, too, did not exhibit a generalized pattern for all patients who had undergone primary alveolar cleft bone grafting procedures. This study emphasizes the great diversity of craniofacial skeletal adjustments made within each group of patients with unilateral cleft lip and palate and cautions the clinician against generalizations concerning a particular treatment protocol.

Primary alveolar cleft bone grafting in unilateral cleft lip and palate: arch dimensions at age 8

The purpose of this investigation is to determine whether primary alveolar cleft bone grafting in infants with unilateral cleft lip and palate (N = 17) leads to less favorable dental arch dimensions at age 8 when compared with other 8-year-old patients with unilateral cleft lip and palate who received no alveolar bone grafting procedures (N = 49). Dental casts were obtained for the primary grafted group, and arch lengths and widths were digitally recorded with a reflex microscope. These arch dimensions were then compared with the reported data for a nongrafted group and a noncleft group of 8-year-old children. The major findings were: 1) that the dental arches of both cleft groups generally demonstrated a significant diminution in length and width (P < 0.05) compared with the noncleft groups, and 2) that the patients who underwent primary alveolar cleft bone grafting showed no statistically significant difference for any arch dimension (P < 0.05) when compared with the nongrafted group lacking this additional surgical procedure.

An algorithm to optimize perioperative blood management in surgery

Innovation in surgical blood management has been fueled by patients' perceptions of the risks associated with allogeneic blood transfusions and by surgeons' attitudes toward the use of allogeneic blood. The challenge is to determine the best blood management strategy to implement in the individual patient, particularly in patients with anemia who are at high risk of allogeneic blood transfusion. An algorithm to estimate safe blood loss based on individual patient parameters has been developed. The algorithm uses patient weight, gender, and preoperative hematocrit level to derive the volume of blood loss that can be tolerated while maintaining a target postoperative hematocrit level. Because the margin of safe blood loss can be anticipated, the most appropriate blood conservation option(s) can be implemented and perioperative blood management can be optimized.

Nightly enteral nutrition support of elderly hip fracture patients: a phase I trial

OBJECTIVE

This non-blinded randomized controlled trial was the first phase of a planned series of investigations designed to test the efficacy of aggressive post-operative enteral nutrition support to decrease the rate of post-operative complications or improve long-term outcomes in specifically defined subgroups of elderly patients who have sustained a hip fracture requiring surgery.

METHODS

Eighteen patients (17 males) were randomized to the treatment (eight male subjects) or control groups. The control group (mean age 76.5+/-6.1 years) received standard post-operative care. Subjects in the treatment group (mean age 74.5+/-2.1 years) received 125 cc/hour of nasoenteral tube feedings over 11 hours each night in addition to standard post-operative nutritional care.

RESULTS

Both the treatment and control groups had reduced volitional nutrient intakes for the first 7 post-operative days (3,966+/-2,238 vs. 4,263+/-2,916 kJ/day [948+/-535 vs. 1019+/-697 kcal/day], p=0.815), but the treatment subjects had a greater total nutrient intake (7,719+/-2,109 vs. 4,301+/-2,858 kJ/day [1845+/-504 vs. 1028+/-683 kcal], p=0.012). On average, treatment subjects were tube fed for 15.8+/-16.4 days. There was no difference between the groups (treatment vs. controls) in the rate of post-operative life-threatening complications (25 vs. 30%, p=1.00) or in-hospital mortality (0 vs. 30%, p=0.216). Mortality within 6 months subsequent to surgery was lower in the treatment group compared to the controls (0 vs. 50%, p=0.036).

DISCUSSION

We conclude that nightly enteral feedings are a safe and effective means of supplementing nutrient intake. The greatest impact of nutrition support may be to reduce mortality.

Visualization of bacterial glycocalyx with a scanning electron microscope

Using a new technique for scanning electron microscopic preparation, bacterial glycocalyx is seen in its natural, highly hydrated state for the first time. Visual images of the glycocalyx obtained from these preparations are a marked departure from the visual images of glycocalyx obtained previously with conventional scanning electron microscopic analysis. The dominating presence of glycocalyx visualized in its naturally hydrated state gives credence to the role of bacterial glycocalyx as a mechanical barrier to host defenses and antibiotics and supports the role of glycocalyx as a significant factor in bacterial virulence.

Relationship between diabetes mellitus and long-term survival after coronary bypass and angioplasty

BACKGROUND

Recent subgroup analyses of randomized trials have suggested that percutaneous intervention in diabetic patients with multivessel disease results in higher mortality than coronary artery bypass graft surgery (CABG). We studied the relationship between diabetes and survival after revascularization in a large prospective cohort of patients with multivessel coronary artery disease.

METHODS AND RESULTS

By analyzing data for 3220 patients (24% diabetic) with symptomatic two- or three-vessel coronary disease who were undergoing percutaneous transluminal coronary angioplasty (PTCA) or CABG at Duke University Medical Center between 1984 and 1990, we found that at 5 years, unadjusted survival in the group of patients undergoing CABG was 74% in diabetics and 86% in nondiabetics. Similarly, 5-year survival among PTCA patients was 76% in diabetics and 88% in patients without diabetes. After adjustment for baseline characteristics, diabetic patients receiving either PTCA or CABG had significantly poorer survival than nondiabetics (chi2=43.56, P<.0001). Unlike previous studies, however, there was no significant differential effect of diabetes on outcome between patients treated with PTCA and those treated with CABG (chi2=0.01, P=.91).

CONCLUSIONS

Although diabetes was associated with a worse long-term outcome after both PTCA and CABG in patients with multivessel coronary artery disease, the effect of diabetes on prognosis was similar in both treatment groups. Thus, our findings support the concept that the choice of initial revascularization strategy should not be based exclusively on a history of diabetes but rather should rely on other factors, such as angiographic suitability and clinical status.

Resurfacing of only the femoral head for osteonecrosis. Long-term follow-up study

Fourteen patients (21 hips) with osteonecrosis of the femoral head with collapse had the femoral head resurfaced with a cemented titanium shell. All of the femoral heads were Ficat stage III or IV. Of the 21 surgeries, 7 were failures. Treatment for all 4 patients with sickle cell disease or trait failed (100%). When the cases of 17 patients who did not have sickle cell disease or trait were reviewed separately, the success rate was 14 of 17 (82%). The follow-up periods (all > 5 years) of the 14 successful patients in this group averaged 6.2 years, and their average Harris hip score was 87 (10 excellent, 4 good). Of the 14 successes, 10 patients had a follow-up period longer than 5 years (average, 7.7 years) and an average Harris hip score of 94 (7 excellent, and 3 good). There was no evidence of loosening and there was no osteolysis. It is concluded that this operation provides an alternative to hemiarthroplasty, total joint arthroplasty surgery, or bipolar arthroplasty. This is a time-buying first-stage operation and, for younger patients, will not last a lifetime. The concept appears prudent because the surgical procedure is directed at the site of primary disease, the femoral head.

Relationship between physician and hospital coronary angioplasty volume and outcome in elderly patients

BACKGROUND

With the expectation that physicians who perform larger numbers of coronary angioplasty procedures will have better outcomes, the American College of Cardiology/ American Heart Association guidelines recommend minimum physician volumes of 75 procedures per year. However, there is little empirical data to support this recommendation.

METHODS AND RESULTS

We examined in-hospital bypass surgery and death after angioplasty according to 1992 physician and hospital Medicare procedure volume. In 1992, 6115 physicians performed angioplasty on 97,478 Medicare patients at 984 hospitals. The median numbers of procedures performed per physician and per hospital were 13 (interquartile range, 5 to 25) and 98 (interquartile range, 40 to 181), respectively. With the assumption that Medicare patients composed one half to one third of all patients undergoing angioplasty, these median values are consistent with an overall physician volume of 26 to 39 cases per year and an overall hospital volume of 196 to 294 cases per year. After adjusting for age, sex, race, acute myocardial infarction, and comorbidity, low-volume physicians were associated with higher rates of bypass surgery (P < .001) and low-volume hospitals were associated with higher rates of bypass surgery and death (P < .001). Improving outcomes were seen up to threshold values of 75 Medicare cases per physician and 200 Medicare cases per hospital.

CONCLUSIONS

More than 50% of physicians and 25% of hospitals performing coronary angioplasty in 1992 were unlikely to have met the minimum volume guidelines first published in 1988, and these patients had worse outcomes. While more recent data are required to determine whether the same relationships persist after the introduction of newer technologies, this study suggests that adherence to minimum volume standards by physicians and hospitals will lead to better outcomes for elderly patients undergoing coronary angioplasty.

Characterization of a rabbit model of staphylococcal osteomyelitis

We previously described a rabbit osteomyelitis model that involved the direct introduction of Staphylococcus aureus into devascularized bone. To further evaluate the model, we performed experiments aimed at correlating the microbiological, radiographic, and histologic parameters involved in the development of experimental osteomyelitis. Using the strain UAMS-1, we achieved an infection rate of 75% with an inoculum as small as 2 x 10(3) colony-forming units. However, development of significant radiographic and histologic signs of disease required an inoculum of at least 2 x 10(4) colony-forming units. Radiographic signs were minimal 1 week after infection and progressed steadily to a maximum 3 weeks after infection. In contrast, histologic signs of disease were observed within 1 week and remained essentially unchanged throughout the 4-week evaluation period. Unlike the results obtained with UAMS-1, rabbits infected with the heavily encapsulated Staphylococcus aureus strain Smith diffuse exhibited little evidence of disease even when infected with 2 x 10(6) colony-forming units. The reduced virulence of strain Smith diffuse was surprising given its greatly enhanced virulence (relative to UAMS-1) in a murine peritonitis model of staphylococcal disease. These results suggest that UAMS-1 expresses virulence factors that are important in the pathogenesis of osteomyelitis and that some or all of these virulence factors are either absent or are not expressed in strain Smith diffuse. Most importantly, the results suggest that our model may be appropriate for the identification and characterization of these virulence factors.

The natural history of single-vessel chronic coronary occlusion: a 25-year experience

To determine the natural history of patients with a total occlusion of a single coronary artery, we searched the Duke Databank for Cardiovascular Disease to find all patients who underwent a first coronary angiogram >2 days after a symptomatic myocardial infarction between 1969 and 1994. Patients who underwent angiography >30 days after the acute event had a low risk of death in the first year (3%), and a proximal left anterior descending coronary occlusion did not confer substantially higher risk of death (4%). Patients undergoing angiography <30 days after the acute event had a higher mortality (5%), especially those with proximal left anterior descending occlusion (10%). The time from the acute event to angiography was a predictor of death (p = 0.04). Despite low 1-year mortality rates, patients with total occlusion of an isolated coronary vessel treated medically had substantial mortality, myocardial infarction, and revascularization rates over a long-term follow-up period.

Treatment of experimental osteomyelitis by surgical debridement and the implantation of bioerodable, polyanhydride-gentamicin beads

Osteomyelitis was induced in the radius in 77 rabbits and confirmed by histological examination and culture. At 4 weeks, the wounds were debrided and the animals were treated with (a) fatty acid dimer-sebacic acid beads (a bioerodable composite) impregnated with 20% or (b) 10% gentamicin sulfate, (c) placebo beads and intramuscular gentamicin sulfate, (d) placebo beads alone, or (e) debridement only. After 4 weeks, eradication of infection was determined by histological examination and culture. Osteomyelitis was eradicated in 93% of the animals treated with the beads and 20% gentamicin, in 67% of those treated with the beads and 10% gentamicin, in 25% of those treated with placebo beads and intramuscular gentamicin, in 7% of those treated with placebo beads alone, and in 12.5% of those treated with debridement only (p values from < 0.001 to 0.02). Fatty acid dimer-sebacic acid beads with gentamicin were then implanted in noninfected rabbits, and gentamicin sulfate concentrations in bone, serum, urine, and wound exudate were measured. Gentamicin sulfate was detectable in bone for as long as 8 weeks after implantation. Levels as high as 4,746 micrograms/ml were present in the wound exudate for the first 7 days. Levels in the serum peaked at 1.03 micrograms/ml. Urine levels peaked at 135 micrograms/ml.