The alpha-7 nicotinic acetylcholine receptor agonist PHA-543613 reduces food intake in male rats

Obesity is a prevalent disease, but effective treatment options remain limited. Agonists of the alpha-7 nicotinic acetylcholine receptor (α7nAChR) promote negative energy balance in mice, but these effects are not well-studied in rats. We tested the hypothesis that central administration of the α7nAChR agonist PHA-543613 (PHA) would decrease food intake and body weight in adult male Sprague Dawley rats. Intracerebroventricular (ICV) PHA administration in chow-fed rats produced a suppression of energy intake and weight gain over 24 h. Next, to evaluate effects of ICV PHA on palatable food intake, rats were maintained on a choice diet of rodent chow and 45 % high fat diet (HFD); under these conditions, ICV PHA produced no significant changes in energy intake from either food, or body weight gain, in the 24 h post-injection. However, when given a choice of chow or a higher-fat 60 % HFD, ICV PHA reduced intake of 60 % HFD, but not chow; body weight gain was also suppressed. Further experiments evaluating conditioned taste avoidance (CTA) and pica in response to ICV PHA suggested that the suppressive food intake and body weight effects after ICV injection of PHA were not due to nausea/malaise. Finally, an operant conditioning study showed that responding on a progressive ratio schedule of reinforcement for high-fat food pellets decreased after ICV PHA. Collectively, these studies show that PHA reduces energy intake under some but not all dietary conditions. Importantly, central PHA decreases both food intake as well as motivation for highly palatable, energy dense foods in rats without inducing nausea/malaise, suggesting that the α7nAChR could be a viable target for developing treatments for obesity.

Chronic pramlintide decreases feeding via a reduction in meal size in male rats

Amylin, a pancreatic hormone, is well-established to suppress feeding by enhancing satiation. Pramlintide, an amylin analog that is FDA-approved for the treatment of diabetes, has also been shown to produce hypophagia. However, the behavioral mechanisms underlying the ability of pramlintide to suppress feeding are unresolved. We hypothesized that systemic pramlintide administration in rats would reduce energy intake, specifically by reducing meal size. Male rats were given b.i.d. administration of intraperitoneal pramlintide or vehicle for 1 week, and chow intake, meal patterns, and body weight were monitored throughout the test period. Consistent with our hypothesis, pramlintide decreased chow intake mainly via suppression of meal size, with corresponding reductions in meal duration on several days. Fewer effects on meal number or feeding rate were detected. Pramlintide also reduced weight gain over the 1-week study. These results highlight that the behavioral mechanisms by which pramlintide produces hypophagia are similar to those driven by amylin itself, and provide important insight into the ability of this pharmacotherapy to promote negative energy balance over a period of chronic administration.

Macronutrient intake: Hormonal controls, pathological states, and methodological considerations

A plethora of studies to date has examined the roles of feeding-related peptides in the control of food intake. However, the influence of these peptides on the intake of particular macronutrient constituents of food - carbohydrate, fat, and protein - has not been as extensively addressed in the literature. Here, the roles of several feeding-related peptides in controlling macronutrient intake are reviewed. Next, the relationship between macronutrient intake and diseases including diabetes mellitus, obesity, and eating disorders are examined. Finally, some key considerations in macronutrient intake research are discussed. We hope that this review will shed light onto this underappreciated topic in ingestive behavior research and will help to guide further scientific investigation in this area.

The alpha-7 nicotinic acetylcholine receptor agonist GTS-21 does not affect food intake in rats

Obesity is a prevalent disease, but effective treatments remain limited. Agonists of the alpha-7 nicotinic acetylcholine receptor (α7nAChR) promote negative energy balance in mice, but these effects are not well-studied in rats. We tested the hypothesis that the α7nAChR agonist GTS-21 would decrease food intake and body weight in adult male Sprague Dawley rats. Contrary to our hypothesis, acute systemic administration of GTS-21 produced no significant effects on chow or high-fat diet (HFD) intake. Acute intracerebroventricular (ICV) GTS-21 also had no impact on chow intake, and actually increased body weight at the highest dose tested. Previous studies suggest that GTS-21 engages the food intake-suppressive glucagon-like peptide-1 (GLP-1) system in mice. As there are known species differences in GLP-1 physiology between mice and rats, we tested the ability of GTS-21 to elicit GLP-1 secretion in rats. Our results showed that plasma levels of total GLP-1 in rats were not significantly altered by peripheral GTS-21 injection. These results represent an advance in understanding how α7nAChR activation impacts energy balance control in rodents and suggest that there may be important differences between rats and mice in the ability of GTS-21/α7nAChR activation to increase secretion of GLP-1.

Effects of pramlintide on energy intake and food preference in rats given a choice diet

Amylin is a peptide hormone involved in the control of energy balance, making the amylin system a potential target for pharmacotherapies to treat obesity. Pramlintide, an amylin analogue, is an FDA-approved medication for the treatment of diabetes that also has food intake- and body weight-suppressive effects. However, it is unknown whether pramlintide may preferentially reduce intake of highly palatable, energy dense food, the overconsumption of which is thought to play a role in the etiology of obesity. Here, we investigate the effects of pramlintide on food intake and body weight in rats given a choice of chow and high fat diet (HFD). Systemic pramlintide injection in rats reduced HFD intake at 3h post-injection, with no effects at other times and no significant effects on chow intake, body weight, or percent preference for HFD. In a separate experiment, the effects of central injection of pramlintide on food intake and body weight were similarly evaluated. Intracerebroventricular pramlintide significantly reduced HFD intake throughout the 24h post-injection, with some suppressive effects on chow intake, and also decreased 24h body weight change. Again, no significant changes were observed in the proportion of calories obtained from HFD. The same intracerebroventricular doses of pramlintide did not induce pica, suggesting that pramlintide-mediated reductions in feeding are not due to nausea/malaise. Our results suggest that pramlintide reduces food intake in rats largely via reductions in intake of HFD versus chow, supporting the idea that the potent effects of pramlintide on palatable food intake may have utility in the treatment of obesity.

Age and Sex Influence Mitochondria and Cardiac Health in Offspring Exposed to Maternal Glucolipotoxicity

Infants of diabetic mothers are at risk of cardiomyopathy at birth and myocardial infarction in adulthood, but prevention is hindered because mechanisms remain unknown. We previously showed that maternal glucolipotoxicity increases the risk of cardiomyopathy and mortality in newborn rats through fuel-mediated mitochondrial dysfunction. Here we demonstrate ongoing cardiometabolic consequences by cross-fostering and following echocardiography, cardiomyocyte bioenergetics, mitochondria-mediated turnover, and cell death following metabolic stress in aged adults. Like humans, cardiac function improves by weaning with no apparent differences in early adulthood but declines again in aged diabetes-exposed offspring. This is preceded by impaired oxidative phosphorylation, exaggerated age-related increase in mitochondrial number, and higher oxygen consumption. Prenatally exposed male cardiomyocytes have more mitolysosomes indicating high baseline turnover; when exposed to metabolic stress, mitophagy cannot increase and cardiomyocytes have faster mitochondrial membrane potential loss and mitochondria-mediated cell death. Details highlight age- and sex-specific roles of mitochondria in developmentally programmed adult heart disease.

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Fetal exposures disrupt mitochondria, bioenergetics, & cardiac function at birth

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First, bioenergetics & function improve until greater reliance on OXPHOS with age

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At 6MO, poor respiration incites biogenesis & mitophagy, and then functional decline

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Fetal exposures cause faster mitochondria-mediated cell death in aged adult hearts

Abstract OT2-07-06: Phase Ib study to assess the safety, tolerability, and clinical activity of gedatolisib in combination with palbociclib and either letrozole or fulvestrant in women with metastatic or locally advanced/recurrent breast cancer (B2151009)

Background:Hormone receptor positive (HR+) disease is the most common subset of advanced breast cancer (BC). The majority of women with HR+ metastatic BC (MBC) develop resistance to endocrine therapy (ET), with a median survival of 2-3 years. A new strategy to treat HR+ MBC involves the combination of ET and a cyclin-dependent kinase 4/6 inhibitor (CDKi 4/6), which has demonstrated improved progression-free survival (PFS) in both first-and later-line MBC. Preclinical evidence in PI3K-mutant cell-line xenografts demonstrated that combinations of PI3K and CDK4/6i reduced intrinsic and adaptive resistance to ET, leading to tumor regression (Vara, 2004; Pfizer data). Inhibition of the PI3K/mTOR pathway by gedatolisib (G) may provide a new therapy to overcome ET resistance. These findings support developing the triplet combination of G with the CDKi 4/6 palbociclib (P)+letrozole (L) or fulvestrant (F) for the treatment of patients (pts) with ER+/HER2- BC.

Methods: This ongoing study in women with ER+/HER2- MBC, in first- and later-line settings, includes a dose-escalation (DE) to evaluate dose-limiting toxicities (DLTs, primary endpoint [pEP]) and determine the maximum tolerated dose and recommended phase 2 dose (RP2D) for a triplet regimen of G+P+L or G+P+F. The escalation rules follow the modified toxicity probability interval method (G doses: 180 and 215 mg IV weekly). Treatment assignment to the triplet is based on investigator decision and bone-only disease is permitted. After RP2D determination for each triplet, a 3-arm expansion for early signs of efficacy (ESOE) will investigate objective response rate (ORR) compared to historical controls [pEP] of Arm A) G+P+L in first-line, B) G+P+F in pts with no prior CDKi 4/6 in second-line and C) G+P+F in pts who have received prior CDKi 4/6. Pts receive G+P (125 mg oral daily for 21 days [D] on and 7 D off) + L (2.5 mg oral daily) or F (500 mg IM on D1, 15 of cycle [C] 1; D1 of C2 and then 500 mg IM on D1 of all 28-D cycles). Secondary endpoints include safety, tumor response (DE), PFS (ESOE), pharmacokinetics (PK), and biomarker correlations associated with the PI3K/mTOR pathway.

Results: 27 pts received G (180 mg/week) in combination with P+L (L cohort, n=12) or P+F (F cohort, n=15). Median prior therapies were: L cohort: 1 (range: 0-4); F cohort: 2 (range 1-5). The 3 most common, drug-related adverse events (%) were in L cohort: nausea (75), neutropenia (67), and stomatitis (67); F cohort: stomatitis (67), nausea (60), and neutropenia (53). C1 DLTs were: L cohort: grade (gr) 3 neutropenia (n=1); F cohort: gr 3 stomatitis (n=1). Preliminary rates of stable disease/partial response were: L cohort: 33%/16%; F cohort: 40%/13%. PK parameters and next-generation sequencing of PI3K-related mutations are pending.

Conclusions: G can be combined with P+L or P+F with manageable toxicity and promising preliminary antitumor activity, even in heavily pretreated pts. Dose escalation, followed by expansion for ESOE, is ongoing.

This study is sponsored by Pfizer. Editorial support was provided by Engage Scientific Solutions and was funded by Pfizer.

Citation Format: Forero A, Han HS, Dees EC, Wesolowski R, Bardia A, Kabos P, Kern KA, Perea R, Pierce KJ, Houk B, Rugo HS. Phase Ib study to assess the safety, tolerability, and clinical activity of gedatolisib in combination with palbociclib and either letrozole or fulvestrant in women with metastatic or locally advanced/recurrent breast cancer (B2151009) [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 OT2-07-06.

Abstract P6-12-05: Ways To Understand Mechanism of Action for Targeted Drugs? Gene Expression Analyses from Paired Biopsies in Patients with Advanced Breast Cancer in a Substudy from the Randomized Study Docetaxel +/− Sunitinib A6181064

Background: The randomized SUN 1064 study, docetaxel +/− sunitinib included 593 patients with advanced breast cancer. The response rate was statistically significantly (p-value=0.001) higher in the combined arm, but no difference in progression free survival or overall survival was found, median 24.8months in combined arm and median 25.5 months in docetaxel arm (HR 1.21: 95% confidence interval 0.91-1.60).

This substudy aimed at unraveling gene expression patterns together with differentially expressed genes, contrasting gene expression before and after docetaxel +/− sunitinib treatment. The study also aimed at testing if sunitinib altered the gene expression of previously proposed sunitinib receptor tyrosine kinase targets. Material and methods:

In a substudy at Karolinska we aimed to have cytological biopsies taken; before start of therapy and repeated in both arms after 14 (+/−1 day) days of therapy, randomly consisting of either docetaxel at 100 mg/m2 q 3 w, or docetaxel 75 mg/m2 q 3w + sunitinib 37.5 mg orally day 2-15. Eighteen of 21 patients accepted participation. From 14 (7 per arm) individuals we had sufficient material to make paired comparisons. We used the HG-U133plus2 Affymetrix chip containing 54 675 probe sets in the 14 paired pre-treatment and post-treatment patient samples.

Results:

Unsupervised hierarchical clustering revealed differential gene expression patterns for the combined arm (Figure A) compared with docetaxel alone (Figure B).

The sunitinib proposed target receptor tyrosine kinases, showed no clustering patterns associated with the combined sunitinib and docetaxel treatment. The top 100 differentially expressed genes did not include the proposed sunitinib target genes. However interestingly, genes involved in the VEGF signaling pathway and apoptosis were significantly more frequently upregulated and those involved in the cell cycle were more frequently down-regulated in patients after treatment of sunitinib and docetaxel in combination, in contrast to the pre-therapy situation.

Conclusions:

Unsupervised hierarchical clustering revealed differential gene expression patterns corresponding to before and after combined sunitinib and docetaxel treatment, clearly clustering patients into the two groups. Interestingly, genes involved in the VEGF signaling pathway, apoptosis and cell cycle were modulated significantly more frequently by combined therapy treatment.

An exploratory study of sunitinib plus paclitaxel as first-line treatment for patients with advanced breast cancer

Background: Sunitinib has shown single-agent activity in patients with previously treated metastatic breast cancer (MBC). We investigated the safety of the combination of sunitinib and paclitaxel in an exploratory study of patients with locally advanced or MBC.

Methods: Patients received oral sunitinib 25 mg/day (with escalation to 37.5 mg/day as tolerated) on a continuous daily dosing schedule and paclitaxel 90 mg/m² on days 1, 8, and 15 of each 28-day cycle. Study endpoints included safety (primary endpoint), pharmacokinetics, and antitumor activity.

Results: Twenty-two patients were enrolled. The most frequent adverse events (AEs) were fatigue/asthenia (77%), dysgeusia (68%), and diarrhea (64%). Grade 3 AEs included neutropenia (43%), fatigue/asthenia (27%), neuropathy (18%), and diarrhea (14%). No drug–drug interaction was observed on the basis of pharmacokinetic analysis. Of 18 patients with measurable disease at baseline, 7 (38.9%) achieved objective responses (including 2 complete and 5 partial responses). Clinical responses were observed in three of nine patients with triple-negative receptor status (estrogen receptor negative, progesterone receptor negative, and human epidermal growth factor receptor-2 negative).

Conclusions: These data indicate that sunitinib and paclitaxel in combination are well tolerated in patients with locally advanced or MBC. No drug–drug interaction was detected and there was preliminary evidence of antitumor activity.

Lymphoscintigraphic anatomy of sentinel lymphatic channels after subareolar injection of Technetium 99m sulfur colloid

BACKGROUND

Injection of Technetium 99m sulfur colloid (Tc-99m-SC) into the subareolar lymphatic plexus provides a rapid and reliable method of identifying breast sentinel lymph nodes and their lymphatic connections to the areola, termed sentinel lymphatic channels (SLCs). The objective of this study was to define the anatomic origin, number, and direction of the SLC in relation to the areola after subareolar injection of Tc-99m-SC.

STUDY DESIGN

Using a hand-held goniometer, the exit angle (theta(e)) and direction from the vertical (to the patient's right or left) of SLCs were determined in 87 successful preoperative lymphoscintigrams (46 left breast and 41 right breast).

RESULTS

One major lymphatic trunk was identified in 91% of cases (n = 79), and two lymphatic trunks were identified in 9% of cases (n = 8). Overall, 24% (n = 21) of major lymphatic trunks exited the areola vertically (theta(e) = 0 degrees), 33% (n = 29) exited the areola with theta(e) = right or left 1 to 30 degrees, and 32% (n = 28) exited with a theta(e) = right or left 31 to 60 degrees. In total, 90% (n = 78) of SLCs exited the areola with a theta(e) = right or left 0 to 60 degrees, equivalent to 10 to 12 o'clock in the right breast, and 12 to 2 o'clock in the left breast.

CONCLUSIONS

Radial angular measurements of SLCs from preoperative lymphoscintigrams performed by SA injection confirm that the origin of the majority of SLCs is within the upper, outer edge of the areola, and that all SLCs ultimatelytraverse the upper, outer quadrant of the breast and terminate on axillary sentinel nodes.

Tactile imaging of breast masses: first clinical report

HYPOTHESIS

Tactile imaging can accurately document the palpable extent of breast masses.

DESIGN

Prospective nonrandomized interventional trial, comparing mass size estimates from preoperative physical examination, ultrasound, and tactile imaging with postoperative measurements of the resected masses.

SETTING

A community ambulatory surgical center and a university hospital tertiary care center.

PATIENTS

Twenty-three women undergoing surgical excision of breast masses. All subjects had a single, palpable, dominant mass, 0.5 to 3 cm in diameter.

INTERVENTION

Prior to surgery, the size of each mass was estimated from tactile imaging using an array of pressure sensors that is stroked over the mass. Size was also estimated by ultrasound and physical examination. Immediately following resection of the mass, it was bisected, and the palpable extent was measured with a caliper.

MAIN OUTCOME MEASURE

Maximum mass diameter estimates from ultrasound, physical examination, and tactile imaging, compared with the resected measurement.

RESULTS

Tactile imaging estimates were repeatable (7.5% mean SD for multiple estimates of the same mass) and show good agreement with the resected measurements. Mean absolute error was 13%, and linear regression with zero intercept had a slope of 0.94, r(2) = 0.51. Physical examination and ultrasound estimates had respective mean absolute errors of 46% and 34%, regression slopes of 1.27 and 0.89, and r(2) = 0.28 and 0.37.

CONCLUSIONS

Tactile imaging can provide accurate and reproducible estimates of the size of breast masses. This capability can enhance cancer surveillance for patients with benign masses (eg, due to scarring or fibrocystic changes) because previous work suggests that reliable detection of a difference in mass size by physical examination requires a 40% change in diameter. In contrast, this study suggests tactile imaging requires only a 15% change (95% confidence interval).

The delayed diagnosis of breast cancer: medicolegal implications and risk prevention for surgeons

The delayed diagnosis of breast cancer is a leading source of error in clinical practice, and an important cause of medical malpractice claims for surgeons and other clinicians. If clinical situations frequently leading to the delayed diagnosis of breast cancer could be predicted, misdiagnosis could be avoided more easily. Therefore, a policy of risk prevention should focus on understanding which group of patients fall into a high-risk profile for diagnostic errors, and why physicians commonly commit errors when evaluating these specific patients. Drawing on multiple sources of medical malpractice information, a profile of high-risk for misdiagnosis was created and analyzed. We have identified a "Triad of Error" for misdiagnosed breast cancer, involving (1) young patients, with (2) self-discovered breast masses, and (3) negative mammograms. The "Triad of Error" accounts for the majority of cases of misdiagnosed breast cancer. An understanding by surgeons and other clinicians of the clinical, biological, and technical basis for the "Triad of Error", and how these factors interact to produce misdiagnoses, should lead to more rapid diagnosis of breast cancer, and fewer medical liability claims. The surgeon plays a central role in preventing the delayed diagnosis of breast cancer by interrupting this cycle of diagnostic error, through the use of tissue sampling techniques that rapidly establish a definitive diagnosis of breast abnormalities.

Preoperative lymphoscintigraphy during lymphatic mapping for breast cancer: improved sentinel node imaging using subareolar injection of technetium 99m sulfur colloid

BACKGROUND

Preoperative lymphoscintigraphy has been recommended to confirm the successful uptake and direction of migration of radiotracer into sentinel nodes during lymphatic mapping for breast cancer. In addition, preoperative lymphatic mapping may provide a visually useful aid to the relative location of sentinel nodes within a nodal basin. One common method of breast lymphoscintigraphy involves injections of unfiltered technetium 99m sulfur colloid (Tc-99m-SC) directly into parenchymal tissues surrounding a tumor or biopsy cavity (IP injection). Because of the many imaging failures and prolonged imaging times of IP lymphoscintigraphy, the procedure has fallen into disfavor by oncologic surgeons. The purpose of this study is to document the increased success rate of preoperative breast lymphoscintigraphy using a new anatomic site of injection, the subareolar lymphatic plexus (SA injection).

STUDY DESIGN

In the 12 months between December 1, 1998, and December 29, 1999, 42 women with stage I and II breast cancer underwent preoperative lymphoscintigraphy by either the IP (n = 12, December 1998 to May 1999) or SA (n = 30, May 1999 to December 1999) route of injection. Both groups were injected with 1 mCi (37 MBq) of unfiltered Tc-99m-SC followed immediately by external gamma-camera imaging. The success rate for preoperative sentinel node imaging and the total imaging time were recorded in both groups.

RESULTS

The success rate of identifying a sentinel node by SA lymphoscintigraphy was 90% (n = 27 of 30 patients), compared with 50% (n = 6 of 12 patients) for IP lymphoscintigraphy (p = 0.009). The imaging time in the SA injection group was 34 +/- 16 minutes, which was 59% shorter than the imaging time in the IP injection group of 82 +/- 48 minutes (p < 0.001). No uptake into internal mammary nodes was seen in either group.

CONCLUSIONS

Moving the site of injection ofunfiltered Tc-99m-SC to the subareolar lymphatic plexus (SA injection) increased the success rate of preoperative lymphoscintigraphy to 90%, compared with 50% using IP injections. Preoperative SA lymphoscintigraphy resulted in the rapid visualization of axillary sentinel nodes within 30 minutes of SA injection, enabling a visual determination of the approximate number of sentinel nodes and their relative locations within the axilla. We conclude SA injection of unfiltered Tc-99m-SC is superior to IP injections when performing preoperative breast lymphoscintigraphy and is a visually useful aid to lymphatic mapping for breast cancer.

Sentinel lymph node mapping in breast cancer using subareolar injection of blue dye

BACKGROUND

Lymphatic mapping in breast cancer performed solely by intraparenchymal injections of blue dye remains an accepted method of identifying sentinel nodes, largely because of its simplicity. As currently practiced, the technique is associated with a marked learning curve, variable identification rates of sentinel nodes, and high false-negative rates. The purpose of this study is to improve dye-only lymphatic mapping of the breast by using an alternative site for injection of blue dye: the subareolar lymphatic plexus.

STUDY DESIGN

In the 10 months between August 1998 and May 1999, 40 women with operable breast cancer in stages I and II underwent lymphatic mapping and sentinel node biopsy performed solely by subareolar injections of blue dye, followed by complete axillary node dissection. The technique involved the injection of 5 mL of 1% isosulfan blue into the subareolar plexus, which consists of breast tissue located immediately beneath the areola. No peritumoral injections of blue dye were performed. The ability of subareolar dye injections to identify sentinel nodes and accurately predict the pathologic status of the axilla was determined and compared with published results for dye-only lymphatic mapping using intraparenchymal injections.

RESULTS

The identification rate of sentinel nodes was 98% (in 39 of 40 patients). Axillary basins harboring positive lymph nodes were found in 15 of these 39 patients (38.5%). Sentinel nodes correctly predicted the status of these 15 positive axillary basins in 100% of the patients. There were no false-negative sentinel node biopsies, indicating a false-negative rate of 0 (in 0 of 15). The overall accuracy, sensitivity, and specificity were 100%.

CONCLUSIONS

Compared with other series of dye-directed lymphatic mapping, the present study of dye-only injections into the subareolar plexus demonstrates a high sentinel node identification rate, absent false-negative rate, and rapid learning curve. On the basis of these findings, we propose that injections into the subareolar lymphatic plexus are the optimal way to perform dye-only lymphatic mapping of the breast.

Carcinogenic potential of silicone breast implants: a Connecticut statewide study

To clarify the carcinogenic potential of silicone breast implants, 680 implant procedures performed on women in Connecticut with no prior history of cancer were correlated with the subsequent development of primary breast and nonbreast cancers. Neoplastic events after the placement of silicone breast implants during the 13-year interval from October 1, 1980, through September 30, 1993, were quantified using a retrospective, linked-registry method. ICD-9-CM discharge codes contained in the Uni formed Hospital Discharge Data Sets (UHDDS) from 34 hospitals across Connecticut were linked to procedure codes for unilateral and bilateral implants, and to medical histories for new malignancies after the implant procedures. Data were cross-linked to the Connecticut Tumor Registry to confirm the clinical history of each cancer. The rates of breast and nonbreast cancers in patients with silicone breast implants were compared with those of a control population drawn from the UHDDS of 1022 women undergoing sterilization by tubal ligation between 1981 to 1985. Ages (mean +/- SD) were similar in the implant group (34 +/- 10 years) and in the sterilization group (32 +/- 6 years). The mean follow-up in the implant group (4.6 years) was also similar to that of the control group (5.4 years). Compared with the control group, the implant group demonstrated lower rates of breast cancer (0.59 versus 0.88 percent, p = 0.35) and nonbreast cancer (0.59 versus 2.7 percent, p = 0.001). Correspondingly, the implant group had a lower relative risk of breast cancer (relative risk = 0.67, 95 percent, confidence interval = 0.20 to 2.17) and nonbreast cancer (relative risk = 0.21, 95 percent, confidence interval = 0.07 to 0.60). Based on these data, it was concluded that silicone breast implants are not carcinogenic, because they are not associated with increased rates of either breast or nonbreast cancers. The validity and threats to the conclusions are discussed, and the results are placed into context with similar findings from other studies.

Malpractice litigation involving laparoscopic cholecystectomy. Cost, cause, and consequences

OBJECTIVE

To analyze 44 cases of malpractice litigation involving laparoscopic cholecystectomy for cost, cause, and consequences of civil court actions.

DESIGN

Survey of national jury verdict reporting services, covering 20 states during the 39-month interval from January 1, 1993, to April 30, 1996. The 44 laparoscopic cholecystectomies were performed during the 40-month interval from February 1, 1989, to June 30, 1992.

MAIN OUTCOME MEASURES

Types of injuries leading to litigation, morbidity and mortality from injuries, trial verdicts, and cost of liability payments.

RESULTS

The 44 injuries composed 4 main categories of injuries: (1) bile duct, n = 27, 61%; (2) bowel, n = 7, 16%; (3) major vascular, n = 4, 9%; and (4) other, n = 6, 14%. Bowel injuries involved trocar or cautery injury; vascular injuries all involved trocars. There were 7 deaths (16%) overall from either septic peritonitis resulting from bowel injury (4 patients [57%]) or bile peritonitis involving spills or cystic duct leaks (3 patients [43%]). No deaths resulted from injury to main bile ducts. Of the 44 cases, 21 (48%) settled out of court (mean payment, $469,711). Of the remaining 23 cases proceeding to trial, 19 (83%) were defended successfully while 4 (17%) concluded with plaintiff jury verdicts (mean payment, $188,772).

CONCLUSIONS

Frequent settlements of cases involving laparoscopic cholecystectomy injuries that are litigated have resulted in a selection of cases of increased defensibility at trial. The high mortality rate from bowel injuries is a new medicolegal finding in laparoscopic cholecystectomies, as expensive to settle (mean payment, $438,000) as laparoscopic cholecystectomy bile duct injury (mean payment, $507,000).

Comparative analysis of complications from I-131 radioablation for well-differentiated thyroid cancer

BACKGROUND

The decision to extend thyroidectomy to the opposite lobe during resection of well-differentiated thyroid cancer should include an analysis of complications of I-131 radioablation directly related to the thyroid remnant. If significant, then contralateral resection would be indicated. To clarify this issue we studied the incidence of complications of I-131 radioablation in 63 cases of well-differentiated thyroid cancer.

METHODS

Retrospective reviews of operative notes, pathology reports, office records, and physician interviews were made. We analyzed operations, complications, and radiation dosing.

RESULTS

Procedures included unilateral thyroidectomy, 10 (15.9%); subtotal thyroidectomy, seven (11.1%); near-total thyroidectomy, 25 (39.7%); and total thyroidectomy, 21 (33.3%). The average ablative dose was 101 mCi (range, 30 to 208 mCi). Nineteen percent (12 of 63) of patients had complications including radiation thyroiditis (eight), chronic sialoadenitis (one), odynophagia (one), facial edema (one), and shingles (one). Near-total or total thyroidectomy resulted in significantly fewer complications compared with lesser resections (8.7% versus 47.1%, p < 0.005).

CONCLUSIONS

The incidence of complications of I-131 radioablation after thyroidectomy for well-differentiated thyroid cancer is related to the extent of thyroidectomy performed. We recommend contralateral thyroid resection (resulting in a near-total or total thyroidectomy) in patients likely to receive postoperative I-131 radioablation.

Medicolegal analysis of bile duct injury during open cholecystectomy and abdominal surgery

To understand the medicolegal impact of bile duct injury, we analyzed 68 cases of biliary injury resulting from open cholecystectomy and abdominal surgery. Cases were litigated within the US civil justice system between 1970 and 1991. Operations resulting in bile duct complications included cholecystectomy for cholelithiasis in 49 patients (72%), common bile duct exploration in 5 patients (7%), and other abdominal operations in 7 patients (10%); 7 operations were of unknown type. The average delay in recognition of injury was 16 days (range 3 to 42). The mortality rate was 18% (12 of 68). Median jury verdict awards in successfully litigated cases were twice that of out-of-court settlements ($500,000 versus $250,000, P = 0.01). Bile duct injury after open cholecystectomy and abdominal surgery has a high mortality rate when diagnosed late, and is expensive to litigate. This review may be useful in defining the medicolegal outcome of similar injuries from laparoscopic cholecystectomy.

Medicolegal perspectives on laparoscopic bile duct injuries

Information from medical litigation serves as an important educational tool for surgeons. We believe that clinicians should be actively involved in a medico-legal analysis of bile duct injuries because it is the clinical expert witness who is called on to educate the lay jury regarding the standards of care in laparoscopic surgery. Ultimately, the strengths or weaknesses of the experts' arguments, as interpreted by the injury, determine the legal outcome of malpractice claims. Although the civil justice system proscribes the method by which litigation is adjudicated, it does not dictate the medical standards serving as benchmarks for treatment. Indeed, clinicians themselves dictate standards of medical care in surgical injuries accompanied by litigation. For this reason, clinicians are justified in their intense interest in the medicolegal aspects of these cases. At the same time, the reader is forewarned that this review focuses on medical factors of bile duct injury and on ideas that are empirically derived from analysis of past negligence litigation. As befits the role of an interested clinician only, no attempt is made to be advisory or complete on matters of case law.

Medicolegal analysis of the delayed diagnosis of cancer in 338 cases in the United States

OBJECTIVE

To define the frequency, clinical characteristics, and legal outcomes of the delayed diagnosis of cancer leading to negligence litigation.

DESIGN

Retrospective review of 338 jury verdict reports from 42 states in the United States.

SETTING

State and federal civil court decisions, as reported to litigation survey services, in a 5-year interval from 1985 to 1990.

RESULTS

Of 338 cancers divided into 13 major organ sites, breast (38%, n = 127), gastrointestinal (15%, n = 51), lung (15%, n = 50), and head and neck cancers (10%, n = 33) accounted for 80% (270/338) of lawsuits. The average diagnostic delay for 212 cases was 17 months. The median age of patients with delays was 15 years younger than the age of patients presenting with cancer in the general population. For cancers in nine major organ sites, the ratio of mortality for patients filing lawsuits to that for patients with cancer in the general population averaged 3.4:1. The total known indemnity payout was $140.2 million, with an average payout per case of $64,600. At 1 to 3 months of diagnostic delay, jury verdicts largely favored the defense (seven of 11 [65%] defense verdicts); after 6 months of delay, jury verdicts were almost evenly divided between defense verdicts, plaintiff verdicts, and out-of-court settlements.

CONCLUSIONS

The delayed diagnosis of cancer leading to negligence litigation is associated with significant indemnity payments, often involves middle-aged patients far younger than the expected age in the general cancer population, and is defensible only in the minority after 6 months of diagnostic delay.

Medicolegal analysis of errors in diagnosis and treatment of surgical endocrine disease

BACKGROUND

The medicolegal impact of adverse events in surgical endocrine disease has not been described previously. This study was undertaken to determine the causes, costs, and outcomes of endocrine malpractice litigation.

METHODS

Jury verdict reports from the U.S. civil court system from 1985 through 1991 were reviewed. Sixty-two malpractice cases were identified from 21 states.

RESULTS

The 62 cases were classified into three categories, totaling 63 adverse events: (1) complications (n = 34, 54%) from thyroid (n = 32, 51%) or parathyroid (n = 2, 3%) surgery; (2) delayed diagnosis (n = 22, 35%) of thyroid cancer (n = 11, 18%), adrenal tumors (n = 9, 14%), and hyperparathyroidism (n = 2, 3%); and (3) medical morbidity (n = 7, 11%) from radioactive iodine (n = 5, 8%) or from propylthiouracil (n = 2, 3%). Surgical injuries, mostly recurrent nerve injuries by general surgeons, accounted for the greatest number of cases and the highest cost of litigation.

CONCLUSIONS

Medical malpractice involving endocrine disease results in expensive litigation, a result of serious harm. Technical misadventures account for most cases, followed closely by delays in diagnosis. These data may aid design of risk prevention strategies in endocrine disease.

Medical malpractice involving colon and rectal disease: a 20-year review of United States civil court litigation

To determine objectively the causes of malpractice litigation involving colon and rectal disease, a retrospective review was undertaken of all cases tried in the U.S. federal and state civil court system over a 21-year period from 1971 through 1991. Ninety-eight malpractice cases were identified from a computerized legal data base, involving 103 allegations of negligence. Allegations fell into five major categories: 1) failure to timely diagnose disease, principally colorectal cancer and appendicitis (n = 44/103; 43 percent); 2) iatrogenic colon injury (n = 25/103; 24 percent); 3) iatrogenic medical complications during diagnosis or treatment (n = 16/103; 15 percent); 4) sphincter injury with fecal incontinence, resulting from anorectal surgery or midline episiotomy (n = 10/103; 10 percent); and 5) lack of informed consent, especially regarding extent of procedures or risk of endoscopy (n = 8/103; 8 percent). These data may aid in design of risk prevention strategies related to the diagnosis and treatment of colorectal disease.

Changing role of splenectomy for hematologic disease

In the past decade the development of accurate imaging and the evolution of the medical management of hematologic diseases has led to changes in the indications for splenectomy for these disorders. To assess the impact of these developments, a multi-institutional, retrospective review was undertaken. One hundred fifty-six splenectomies were performed for hematologic disorders between July 1, 1979 and June 30, 1991. Patients were divided into 2 groups: those undergoing splenectomy from 1979-1985 (Period I), and those undergoing splenectomy from 1986-1991 (Period II). Diseases were classified into 3 groups: cytopenic/anemic conditions, symptomatic splenomegaly, and Hodgkin's disease. Data was compared between the two periods using chi-square analysis. More splenectomies were performed for hematologic disorders during Period II than Period I (P < .005). This increase is secondary to a rise in the number of splenectomies performed for cytopenia/anemia during Period II. In contrast, splenectomies for splenomegaly and Hodgkin's disease decreased during Period II (P < .005 and < .05). More Hodgkin's patients were upstaged on the basis of positive laparotomy findings in Period II, compared to Period I (40% versus 10%, P = .01). Surgeons are now performing more splenectomies for cytopenic/anemic diseases, and fewer for splenomegaly and Hodgkin's disease. These results are consistent with recent trends: (1) earlier splenectomy in patients with cytopenia/anemia; (2) earlier medical intervention in infiltrative splenic disorders; and (3) more reliance on radiologic staging in Hodgkin's disease and widespread use of combination chemotherapy, leaving surgical staging for those cases in which treatment would be changed by laparotomy findings.

Causes of breast cancer malpractice litigation. A 20-year civil court review

To determine objectively the patient and physician factors that lead to breast cancer malpractice litigation, a review was undertaken of all cases tried in the US federal and state civil court system over a 20-year period from 1971 through 1990. Forty-five cases were identified and all involved a delayed diagnosis of breast cancer (the mean delay was 15 months). The patients were young (mean age, 40 years). Of 45 cases studied, the majority of patients (37 [82%]) found a painless mass by self-examination of the breast. Only 22 patients (49%) had further workup, mostly by mammography (20 [44%]). The results of 16 mammograms (80%) were read as normal. Obstetricians and gynecologists were involved in the greatest number of cases (21 [50%]), followed by family practitioners and internists (17 [41%]), general surgeons (12 [28%]), and radiologists (4 [10%]).

[14C]deoxyglucose uptake and imaging in malignant melanoma

Since malignant tumors utilize more glucose than normal tissues, tumor uptake and autoradiographic imaging studies using the 14C-labeled glucose analog 2-deoxyglucose (DG) provide a useful preclinical system to determine if similar human tumors will image in vivo with positron emission tomography (PET) using 18F-labeled DG (FDG-PET). We studied B16 murine melanomas of increasing metastatic potential (F1, low; BL-6, intermediate; F10, high) as a feasibility study to determine the potential for human melanoma imaging using FDG-PET. Male C57BL-6 mice (50 g) were implanted sc with 1-mm3 fragments of B16 melanomas. Fourteen days later mice were injected ip with 1.25 muCi of [14C]DG. Sixty minutes later tumor (T) and gastrocnemius muscle (M) were harvested, solubilized, and counted for [14C]DG dpm/mg to estimate glucose utilization. Autoradiographic imaging was carried out similarly, using 2.0 muCi or [14C]DG with 30-day exposure of T and M tissue sections (20 microns thick) to X-ray film. The uptake of [14C]DG (expressed as dpm/mg; % injected dose/g; and tumor-to-muscle uptake ratios) was 6 to 10 times higher in tumors than in muscle tissue (P less than 0.001). All three melanoma cell lines imaged successfully with [14C]DG autoradiography. Tumor uptake of [14C]DG did not correlate with increasing metastatic potential. The experimental B16 murine melanomas F1, BL-6, and F10 extract glucose at higher rates than muscle tissue, a property necessary for successful PET imaging of cutaneous melanoma. The lack of correlation between glucose extraction and metastatic potential suggests that the demands for glucose during tumor growth and metastasis are not related. This is the first laboratory study to predict that human malignant melanoma will image with FDG-PET.

Technique for high volume drainage beneath large tissue flaps

We have found that a chest tube placed beneath large tissue flaps and connected to a standard closed pleural drainage system gives superior results in terms of approximation of tissues and evacuation of the fluid to any available self-contained suction drain. This system makes continuous high volume drainage possible without sacrificing the mobility of the patient or the sterility of the drainage system. Quantifying daily drainage into the closed pleural drainage system is easy for nurses and surgical staff alike. We suggest that this type of drainage system is applicable to a wide variety of reconstructions of the abdominal and chest walls involving extensive soft tissue flaps.

Gastric cancer: a neoplastic enigma

Effective therapy for gastric cancer remains elusive, and thus surgeons, oncologists, and radiotherapists are continually confounded. Multiple attempts to improve survival in gastric cancer patients have failed, including extended lymphadenectomy (by American surgeons), single- or multiple-agent chemotherapy, and combined-modality therapy (multiple-agent chemotherapy combined with radiation therapy). Such studies have been plagued by the high volume of inadequate antitumor responses or by lethal toxicity. At present, chemotherapy remains the best hope for effective adjuvant therapy, but new routes of drug delivery that will decrease systemic toxicity must be developed. Since gastric cancer recurs locoregionally and infrequently metastasizes to distant sites until very late in its course, theory suggests intraperitoneal (IP) chemotherapy applied to locoregional sites should decrease recurrence without significant systemic toxicity. Such treatments have been effective in other malignancies that commonly occur IP, such as ovarian cancer. Intracavitary chemotherapy protocols for gastric cancer are under development and will soon produce data on treatment efficacy. Such studies offer a theoretic basis for improved survival from gastric cancer; however, only well-controlled treatment trials will confirm if theory can be translated into clinical reality.

Cancer cachexia

Cancer cachexia describes a syndrome of progressive weight loss, anorexia, and persistent erosion of host body cell mass in response to a malignant growth. Although often associated with preterminal patients bearing disseminated disease, cachexia may be present in the early stages of tumor growth before any signs or symptoms of malignancy. A decline in food intake relative to energy expenditure (which may be increased, normal, or decreased) is the fundamental physiologic derangement leading to cancer-associated weight loss. In addition, abnormalities of host carbohydrate, protein, and fat metabolism lead to continued mobilization and ineffective repletion of host tissue, despite adequate nutritional support. Mediators of cancer anorexia and associated abnormalities are unknown. Cachectin/TNF or other host-derived cytokines (produced as a defense against malignancy) have been implicated as signal molecules in cachexia, based upon similar metabolic derangements produced by these cytokines in other chronic wasting illnesses. Nutritional support is effective in maintaining body weight of cachectic cancer patients, but ineffective in maintaining lean body mass. Although in one study parenteral nutritional support has improved operative morbidity and mortality in cancer patients, it has not yet improved response to chemotherapy or radiation therapy. Because of metabolic derangements seen in cancer cachexia, effective nutritional treatment regimens will probably require manipulation of host intermediary metabolism in addition to feeding. Insulin therapy or exercise are two such methods which appear to preserve host composition by preferential feeding of the host at the expense of the tumor. Future studies which more clearly define the role of signal molecules in producing cancer cachexia syndrome may lead to new treatment strategies, possibly involving modulation of the effects of such molecules on host metabolism.

Metabolic imaging of human extremity musculoskeletal tumors by PET

The measurement of glucose utilization rate (GUR) by positron emission tomography (PET) using 18F-2-fluoro-2-deoxy-D-glucose (FDG) is a valuable method to assess the grade of malignancy of brain tumors. We have designed a feasibility trial to determine whether PET could be used to image and predict the grade of malignancy of human extremity musculoskeletal tumors. Five patients with extremity tumors (four soft-tissue tumors and one osteogenic tumor) were studied. Peak and mean apparent GURs were determined in the tumor region. All tumors were subsequently resected and graded in a standard fashion using the NCI grading system. Peak apparent GURs ranged from 3.3 mg/100 g/min to 15.2 mg/100 g/min, with the highest values found in the high grade tumors. Although the number of patients studied was small, a good correspondence was shown between GURs and histopathologic grading. Our results indicate that PET can be used to image and evaluate the metabolic activity of human musculoskeletal tumors.

Autoradiographic imaging of rat sarcoma in different anatomical sites using 2-[14C]deoxyglucose

As sarcomas are known to have accelerated glycolysis, we used the radiolabeled glucose analogue 2-deoxy-d-[U-14C]glucose in autoradiographic imaging studies of a methylcholanthrene-induced rat fibrosarcoma placed in an i.m. site, and in models of pulmonary and hepatic metastases. Fifty muCi of 2-deoxy-d-[U-14C]glucose were injected i.p. into groups of rats bearing tumors in these three sites; sacrifice of animals for imaging was carried out 45 min later. Excellent imaging of sarcoma tissue in all three anatomical sites was obtained, with high visual contrast compared to the normal tissue background. Using densitometry of autoradiographs, tumor/tissue ratios were 7.1 for i.m. tumors, 3.8 for pulmonary metastases, and 2.8 for hepatic metastases. Autoradiographic imaging of sarcomas may be obtained based upon avidity of neoplastic tissue for the glucose analogue 2-deoxy-d-[U-14C] glucose. Such imaging is not dependent upon anatomical site and reproducibly images rat sarcomas in muscle, lung, and liver.

Inhibition of established rat fibrosarcoma growth by the glucose antagonist 2-deoxy-D-glucose

Sarcoma cells exhibit higher rates of glycolysis than normal tissues and may be dependent on glucose utilization for growth. Accordingly, we tested the ability of the glucose antimetabolite 2-deoxy-D-glucose (2-DG) to inhibit the growth of an established methylcholanthrene-induced rat fibrosarcoma in three groups of F344 rats with increasing subcutaneous inoculations of tumor (2 X 10(6) cells, 1 X 10(7) cells, and 1 mm tumor fragments). Rats were randomized to receive 2-DG or saline solution at doses of 0.75 gm/kg, 1.5 gm/kg, or 1.75 gm/kg, beginning 3 days after tumor implantation and continuing for 10 days. Tumors were removed and weighed on day 14. We measured tissue [14C]-2-DG levels in tumor, brain, liver, and muscle after intraperitoneal injection of radiolabeled 2-DG. In these same tissues we determined the activity of glucose-6-phosphatase (G-6-Pase), an enzyme which dephosphorylates the intracellular glycolytic inhibitor 2-DG-6-phosphate, thus reversing the antitumor effect of 2-DG. All groups treated with 2-DG had a significant reduction in tumor weight of 50% to 70% when compared with saline solution-treated controls. Toxicity was substantial at the highest dose of 2-DG, but minimal toxicity was noted at intermediate and low doses. Tumor had the greatest uptake of [14C]-2-DG, with low levels of G-6-Pase leading to prolonged retention and highest tissue levels of radiolabeled 2-DG. Use of 2-DG inhibits established sarcoma growth because it is rapidly transported into tumors, cannot be metabolized after phosphorylation, and is dephosphorylated and released slowly from tumor cells. Rat sarcoma growth is dependent on glucose utilization and can be effectively inhibited by glucose antagonism.

Branched chain amino acid-enriched solutions in the septic patient. A randomized, prospective trial

A prospective, randomized trial was undertaken to compare the nutritional efficacy in surgical stress of a standard amino acid solution and two branched chain-enriched amino acid solutions: one enriched primarily with valine, the other with leucine. The study comprised 37 patients in the surgical intensive care unit who received isocaloric, isonitrogenous parenteral nutrition started within 24 hours of the onset of major operation, injury, or sepsis. Nitrogen retention was marginally but statistically significantly better on days 5, 7, and 10 in both groups of patients receiving the branched chain-enriched solutions, but differences in cumulative nitrogen balance were not statistically significant. Amino acid composition appeared to be important in that the group receiving the leucine-enriched solution appeared to maintain hepatic protein synthesis better (as manifest by higher short-turnover plasma protein concentrations) and required less exogenous insulin to maintain euglycemia. Improved outcome was not seen in the groups receiving the branched chain-enriched solutions.

Use of a branched chain amino acid enriched solution in patients under metabolic stress

The metabolic response to stress results in proteolysis, increased gluconeogenesis, and negative nitrogen balance. Infusion of BCAA has been shown experimentally to decrease protein degradation and stimulate protein synthesis. Such infusion may modify the response of patients to metabolic stress. An amino acid solution containing 45 percent BCAA as a component of central vein parenteral nutrition was infused into 20 moderately to severely stressed postoperative patients in a prospective, nonrandomized fashion. Infusion was begun within 24 hours postoperatively and continued for 7 to 14 days. Patients received 1.6 g protein equivalents per kg body weight daily and 30 kcal/kg body weight daily. Nutritional indexes as measured by albumin and transferrin values were maintained during the study period. Nitrogen balance became increasingly positive over the period of infusion without an increase in the urinary excretion of 3-methylhistidine. There were no serious clinical or biochemical side effects of the BCAA infusion, although a statistically significant increase in alkaline phosphatase was observed. These results suggest that central vein parenteral nutrition utilizing a 45 percent BCAA enriched solution can promote nitrogen retention without serious side effects in moderately to severely stressed patients.

Albumin turnover in sarcoma-bearing rats in relation to cancer anorexia

Hypoalbuminemia, a frequent finding in cancer patients, can be demonstrated in the tumor-bearing rat. In actuality, the circulating amount of albumin is maintained in tumor-bearing rats, although total body water and plasma volume are increased. The fractional degradation rate of newly synthesized albumin labelled by the injection of carbon-14-carbonate was significantly increased in tumor-bearing rats (half-life 55 hours) as compared with control rats (half-life 85 hours). These findings indicate maintained synthesis of albumin in the tumor-bearing rats, a finding consistent with an increased ratio of specific activity in albumin to that in plasma urea after the injection of carbon-14-carbonate. Hypoalbuminemia in cancer seems to be the net result of an increased turnover rate of albumin and dilution of the maintained albumin mass. Despite the presence of cancer anorexia, the flux of substrates from the degradation of peripheral tissues is sufficient to supply the liver and, in turn, to enable an increased protein synthesis with maintenance of the synthetic rate of albumin.

The effect of a new branched chain--enriched amino acid solution on postoperative catabolism

Branched-chain amino acids (BCAAs) may regulate muscle amino acid flux. Metabolic studies of both experimental animals and humans utilizing comparatively large amounts of BCAAs infused with hypocaloric glucose have shown that catabolism and proteolysis can be blunted. These studies suggested that the nitrogen-sparing properties of amino acid solutions used in postoperative trauma or sepsis might be improved by increasing the amount of BCAAs. This hypothesis was tested on ten patients undergoing operations of moderate severity utilizing a peripheral amino acid mixture with a branched-chain:non-branched-chain ratio of 45:55% given in 5% dextrose. The patients received 1.7 gm of protein equivalent/kg of ideal body weight in 5% dextrose-crystalloid solution with a concentration of 3.5% amino acids for the first 5 postoperative days. Nitrogen balance, 3-methylhistidine excretion, blood chemistries, and plasma amino acid profile tests were done daily. The results showed that nitrogen equilibrium was maintained for 5 postoperative days without any untoward effects on patients, their surgical wounds, or hepatic function. Plasma amino acids showed no significant changes from baseline with the exception of elevations of the BCAAs. We conclude that this 45% BCAA-enriched solution may be safely administered to patients with postoperative traumatic injury and results in nitrogen equilibrium over a 5-day period.