Machine learning for the prediction of pathologic pneumatosis intestinalis

BACKGROUND

The radiographic finding of pneumatosis intestinalis can indicate a spectrum of underlying processes ranging from a benign finding to a life-threatening condition. Although radiographic pneumatosis intestinalis is relatively common, there is no validated clinical tool to guide surgical management.

METHODS

Using a retrospective cohort of 300 pneumatosis intestinalis cases from a single institution, we developed 3 machine learning models for 2 clinical tasks: (1) the distinction of benign from pathologic pneumatosis intestinalis cases and (2) the determination of patients who would benefit from an operation. The 3 models are (1) an imaging model based on radiomic features extracted from computed tomography scans, (2) a clinical model based on clinical variables, and (3) a combination model using both the imaging and clinical variables.

RESULTS

The combination model achieves an area under the curve of 0.91 (confidence interval: 0.87-0.94) for task I and an area under the curve of 0.84 (confidence interval: 0.79-0.88) for task II. The combination model significantly (P < .05) outperforms the imaging model and the clinical model for both tasks. The imaging model achieves an area under the curve of 0.72 (confidence interval: 0.57-0.87) for task I and 0.68 (confidence interval: 0.61-0.74) for task II. The clinical model achieves an area under the curve of 0.87 (confidence interval: 0.83-0.91) for task I and 0.76 (confidence interval: 0.70-0.81) for task II.

CONCLUSION

This study suggests that combined radiographic and clinical features can identify pathologic pneumatosis intestinalis and aid in patient selection for surgery. This tool may better inform the surgical decision-making process for patients with pneumatosis intestinalis.

Determination of Pesticide Residues in Nonfatty Fooda by Percritical Extraction aqnd Gas Chromatography/Mass Spectrometry: Collaborative Study

A collaborative study was conducted to determine multiple pesticide residues in apple, green bean, and carrot by using supercritical fluid extraction(SFE) and gas chromatography/mass spectrometry(GC/MS). Seventeen laboratories from 7 countries participated in the final study, and a variety of different instruments was used by collaborators. The procedure simply entails 3 steps: (1) mix 1.1 g drying agent (Hydromatrix) per 1 g frozen precomminuted sample, and load 4–5.5 g of this mixture into a 7–10 mL extraction vessel; (2) perform SFE for 20–30 min with a 1–2 mL/min flow rate of carbon dioxide at 0.85 g/mL density (320 atm, 60°C); and (3) inject the extract, which was collected on a solid–phase or in a liquid trap, into the gas chromatograph/mass spectrometer, using either an ion-trap instrument in full-scan mode or a quadrupole-type instrument in selected-ion monitoring mode. The ability of GC/MS to simultaneously quantitate and confirm the identity of the semivolatile analytes at trace concentrations is a strong feature of the approach. The selectivity of SFE and GC/MS avoids the need for post-extraction cleanup steps, and the conversion of the CO2 solvent to a gas after SFE eliminates the solvent evaporation step common in traditional methods. The approach has several advantages, but its main drawback is the lower recoveries for the most polar analytes, such as methamidophos and acephate, and the most nonpolar analytes, such as pyrethroids. Recoveries for most pesticides are &gt;75%, and recoveries of nonpolar analytes are still &gt;50%. The(within-laboratory) repeatability relative standard deviation (RSDr) values of the recoveries are generally &lt;15%. More specifically, the average results from the 9–14 laboratories in the final analysis of 6 blind duplicates at 3 concentrations for each pesticide are as follows: carbofuran in apple (75–500 ng/g), 89% recovery, 7% RSDr, 9% reproducibility relative standard deviation (RSDR); diazinon in apple (60–400 ng/g), 83% recovery, 13% RSDr, 17% RSDMR; vinclozolin in apple (6–400 ng/g), 97% recovery, 13% RSDr, 18% RSDR; chlorpyrifos in apple (50–300 ng/g), 105% recovery, 11% RSDr, 13% RSDR; endosulfan sulfate in apple (150–1000 ng/g), 95% recovery, 15% RSDr, 17% RSDR; trifluralin in green bean (30–200 ng/g), 58% recovery, 11% RSDr, 27% RSDR; dacthal in green bean (60–400 ng/g), 88% recovery, 11% RSDr, 17% RSDR; quintozene in green bean (60–400 ng/g), 79% recovery, 13% RSDr, 18% RSDR; chlorpyrifos in green bean (50–300 ng/g), 84% recovery, 11% RSDr, 17% RSDR; p,p′ -DDE in green bean (45–300 ng/g), 64% recovery, 14% RSDr, 27% RSDR; atrazine in carrot (75–500 ng/g), 90% recovery, 11% RSDr, 15% RSDR; metalaxyl in carrot (75–500 ng/g), 89% recovery, 8% RSDr, 12% RSDR; parathion–methyl in carrot (75–500 ng/g), 84% recovery, 14% RSDr, 15% RSDR; chlorpyrifos in carrot (50–300 ng/g), 77% recovery, 13% RSDr, 19% RSDR; and bifenthrin in carrot (90–600 ng/g), 63% recovery, 12% RSDr, and 25% RSDR. All analytes except for the nonpolar compound strifluralin, p,p′ -DDE, and bifenthrin gave average Horwitz ratios of &lt;1.0 when AOAC criteria were used. These 3 analytes had high RSDr values but lower RSDR values, which indicated that certainSFE instruments gave consistently lower recoveries for nonpolar compounds. The collaborative study results demonstrate that the method meets the purpose of many monitoring programs for pesticide residue analysis, and the Study Director recommends that it be adopted Official

Sumoylation of the astroglial glutamate transporter EAAT2 governs its intracellular compartmentalization

EAAT2 is a predominantly astroglial glutamate transporter responsible for the majority of synaptic glutamate clearance in the mammalian central nervous system (CNS). Its dysfunction has been linked with many neurological disorders, including amyotrophic lateral sclerosis (ALS). Decreases in EAAT2 expression and function have been implicated in causing motor neuron excitotoxic death in ALS. Nevertheless, increasing EAAT2 expression does not significantly improve ALS phenotype in mouse models or in clinical trials. In the SOD1-G93A mouse model of inherited ALS, the cytosolic carboxy-terminal domain is cleaved from EAAT2, conjugated to SUMO1, and accumulated in astrocytes where it triggers astrocyte-mediated neurotoxic effects as disease progresses. However, it is not known whether this fragment is sumoylated after cleavage or if full-length EAAT2 is already sumoylated prior to cleavage as part of physiological regulation. In this study, we show that a fraction of full-length EAAT2 is constitutively sumoylated in primary cultures of astrocytes in vitro and in the CNS in vivo. Furthermore, the extent of sumoylation of EAAT2 does not change during the course of ALS in the SOD1-G93A mouse and is not affected by the expression of ALS-causative mutant SOD1 proteins in astrocytes in vitro, indicating that EAAT2 sumoylation is not driven by pathogenic mechanisms. Most interestingly, sumoylated EAAT2 localizes to intracellular compartments, whereas non-sumoylated EAAT2 resides on the plasma membrane. In agreement, promoting desumoylation in primary astrocytes causes increased EAAT2-mediated glutamate uptake. These findings could have implications for optimizing therapeutic approaches aimed at increasing EAAT2 activity in the dysfunctional or diseased CNS.

Developing a molecular imaging agent for Met using onartuzumab (MetMAb)

11083

Background: Developing an imaging agent to assess Met expression would aid in diagnosis and monitoring tumor response to Met-targeted therapies. Onartuzumab (MetMAb), a Met selective humanized one-armed monoclonal antibody, has been studied in Phase I-II clinical trials in which it was generally well tolerated and has shown the most benefit in patients with MET positive tumors. Methods: Studies to assess Met-binding were executed using the human gastric carcinoma cell line MKN-45 which exhibits a high level of Met expression. Murine PET studies and biodistribution assays were performed using MKN-45 xenografts. Results: Plasma shed Met concentration is directly related to total tumor burden (p < 0.001). The absence of a positive correlation between shed Met and %ID in blood indicates that binding of tracer to shed Met present in plasma is unlikely. There are positive correlations between tumor mass, Met abundance, and phosphoMet content and uptake of 89Zr-df-onartuzumab in MKN-45 mouse xenografts. Lastly, tumor mass, Met, pMet and 89Zr-df-onartuzumab uptake were all significantly decreased by drug treatment. Conclusions: MKN-45 tumor uptake of 89Zr-df-onartuzumab correlated significantly with tumor mass and Met abundance. Blood tracer uptake did not positively correlate with the presence of plasma shed Met. The amounts of Met, pMet, as well as 89Zr-df-onartuzumab image intensity correlated significantly with tumor size (all Spearman p values < 0.001).Tumor volumes and Met content were significantly decreased in TKI treated versus control mice, which correlated with imaging results.89Zr-df-onartuzumab has potential utility for imaging Met to identify patients for treatment with Met-targeted therapeutics and to identify the emergence of Met-driven acquired resistance to other molecularly targeted cancer therapies.

Immuno-PET of the hepatocyte growth factor receptor Met using the 1-armed antibody onartuzumab

The overexpression and overactivation of hepatocyte growth factor receptor (Met) in various cancers has been linked to increased proliferation, progression to metastatic disease, and drug resistance. Developing a PET agent to assess Met expression would aid in the diagnosis and monitoring of responses to Met-targeted therapies. In these studies, onartuzumab, the experimental therapeutic 1-armed monoclonal antibody, was radiolabeled with (76)Br or (89)Zr and evaluated as an imaging agent in Met-expressing cell lines and mouse xenografts.

METHODS

(89)Zr-desferrioxamine (df)-onartuzumab was synthesized using a df-conjugate; (76)Br-onartuzumab was labeled directly. Met-binding studies were performed using the human tumor-derived cell lines MKN-45, SNU-16, and U87-MG, which have relatively high, moderate, and low levels of Met, respectively. Biodistribution and small-animal PET studies were performed in MKN-45 and U87-MG xenografts.

RESULTS

(76)Br-onartuzumab and (89)Zr-df-onartuzumab exhibited specific, high-affinity Met binding (in the nanomolar range) that was concordant with established Met expression levels. In MKN-45 (gastric carcinoma) xenografts, both tracers cleared slowly from nontarget tissues, with the highest uptake in tumor, blood, kidneys, and lungs. (76)Br-onartuzumab MKN-45 tumor uptake remained relatively constant from 18 h (5 percentage injected dose per gram of tissue [%ID/g]) to 48 h (3 %ID/g) and exhibited tumor-to-muscle ratios ranging from 4:1 to 6:1. In contrast, (89)Zr-df-onartuzumab MKN-45 tumor uptake continued to accumulate from 18 h (10 %ID/g) to 120 h (23 %ID/g), attaining tumor-to-muscle ratios ranging from 20:1 to 27:1. MKN-45 tumors were easily visualized in imaging studies with both tracers at 18 h, but after 48 h (89)Zr-df-onartuzumab image quality improved, with at least 2-fold-greater tumor uptake than nontarget tissues. MKN-45 tumor uptake for both tracers correlated significantly with tumor mass and Met expression and was not affected by the presence of plasma shed Met.

CONCLUSION

(89)Zr-df-onartuzumab and (76)Br-onartuzumab specifically targeted Met in vitro and in vivo; (89)Zr-df-onartuzumab achieved higher tumor uptake and tumor-to-muscle ratios than (76)Br-onartuzumab at later times, suggesting that (89)Zr-df-onartuzumab would be better suited to image Met for diagnostic and prognostic purposes.

Hormone predictors of abnormal bone microarchitecture in women with anorexia nervosa

Osteopenia is a complication of anorexia nervosa (AN) associated with a two- to three-fold increase in fractures. Nutritional deficits and hormonal abnormalities are thought to mediate AN-induced bone loss. Alterations in bone microarchitecture may explain fracture risk independent of bone mineral density (BMD). Advances in CT imaging now allow for noninvasive evaluation of trabecular microstructure at peripheral sites in vivo. Few data are available regarding bone microarchitecture in AN. We therefore performed a cross-sectional study of 23 women (12 with AN and 11 healthy controls) to determine hormonal predictors of trabecular bone microarchitecture. Outcome measures included bone microarchitectural parameters at the ultradistal radius by flat-panel volume CT (fpVCT); BMD at the PA and lateral spine, total hip, femoral neck, and ultradistal radius by dual energy X-ray absorptiometry (DXA); and IGF-I, leptin, estradiol, testosterone, and free testosterone levels. Bone microarchitectural measures, including apparent (app.) bone volume fraction, app. trabecular thickness, and app. trabecular number, were reduced (p<0.03) and app. trabecular spacing was increased (p=0.02) in AN versus controls. Decreased structural integrity at the ultradistal radius was associated with decreased BMD at all sites (p<or=0.05) except for total hip. IGF-I, leptin, testosterone, and free testosterone levels predicted bone microarchitecture. All associations between both IGF-I and leptin levels and bone microarchitectural parameters and most associations between androgen levels and microarchitecture remained significant after controlling for body mass index. We concluded that bone microarchitecture is abnormal in women with AN. Endogenous IGF-I, leptin, and androgen levels predict bone microarchitecture independent of BMI.

Adrenal glucocorticoid and androgen precursor dissociation in anorexia nervosa

CONTEXT

Anorexia nervosa is characterized by hypogonadism and relative hypercortisolemia. We have demonstrated that free testosterone levels are low in women with anorexia nervosa, with the lowest levels in those receiving oral contraceptives (OCPs), and that dehydroepiandrosterone (DHEA) sulfate is reduced only in those receiving OCPs.

OBJECTIVE

The aim of the study was to determine whether adrenal steroidogenesis dysregulation contributes to decreased androgen levels in anorexia nervosa.

DESIGN AND SETTING

We conducted a cross-sectional study in a General Clinical Research Center.

STUDY PARTICIPANTS

We studied 20 women with anorexia nervosa [10 women with anorexia nervosa receiving OCPs (AN+E) and 10 not receiving OCPs (AN-E)] and 20 healthy controls [10 healthy controls receiving OCPs (HC+E) and 10 not receiving OCPs (HC-E)].

MAIN OUTCOME MEASURES

We measured DHEA and cortisol levels in response to 250-microg cosyntropin stimulation after 1-mg overnight dexamethasone suppression.

RESULTS

Mean basal and stimulated, peak stimulated, and area under the curve (AUC) cortisol levels were higher in AN-E than HC-E, but mean basal and stimulated, peak and AUC DHEA were comparable. Mean AUC and peak cortisol were higher and DHEA AUC was lower in AN+E than AN-E. However, after controlling for cortisol binding globulin levels, peak and AUC cortisol were comparable between AN+E and AN-E. After controlling for albumin levels, AUC DHEA was comparable between AN+E and AN-E.

CONCLUSIONS

Adrenal glucocorticoid and androgen precursor secretion are dissociated in anorexia nervosa, with relative hypercortisolemia and a preservation of DHEA secretion. Reduced DHEA response to cosyntropin in women receiving OCPs is attributable to decreased albumin levels. In the setting of relative hypercortisolemia, reduced adrenal androgen precursor secretion is not a mechanism underlying low testosterone levels in anorexia nervosa.

Antimicrobial photodynamic efficacy of side-chain functionalized benzo[a]phenothiazinium dyes

5-(Ethylamino)-9-diethylaminobenzo[a]phenothiazinium chloride (EtNBS) is a photosensitizer (PS) with broad antimicrobial photodynamic activity. The objective of this study was to determine the antimicrobial photodynamic effect of side chain/end group modifications of EtNBS on two representative bacterial Gram-type-specific strains. Two EtNBS derivatives were synthesized, each functionalized with a different side-chain end-group, alcohol or carboxylic acid. In solution, both exhibited photochemical properties consistent with those of the EtNBS parent molecule. In vitro photodynamic therapy experiments revealed an initial Gram-type-specificity with two representative strains; both derivatives were phototoxic to Staphylococcus aureus 29,213 but the carboxylic acid derivative was nontoxic to Escherichia coli 25,922. This difference in photodynamic efficacy was not due to a difference in the binding of the two molecules to the bacteria as the amount of both derivatives bound by bacteria was identical. Interestingly, the carboxylic acid derivative produced no fluorescence emission when observed in cultures of E. coli via fluorescence microscopy. These early findings suggest that the addition of small functional groups could achieve Gram-type-specific phototoxicity through altering the photodynamic activity of PSs and deserve further exploration in a larger number of representative strains of each Gram type.

The role of childhood and adulthood abuse among women presenting for chronic pain management

OBJECTIVE

This study investigated the association between repeated childhood and adulthood abuse and somatic symptom reporting, mental health care use, and substance use among women with chronic pain.

DESIGN

A survey of a consecutive sample.

PATIENTS

Ninety consecutive women patients presenting for chronic pain management at a multidisciplinary pain management center.

OUTCOME MEASURES

The authors assessed the presence or absence of physical or sexual abuse (using the Drossman Physical-Sexual Abuse Survey), period of abuse, demographics, mental health care use, drug or alcohol use and substance abuse, and the presence or absence of physical, pain, and anxiety (somatic) symptoms.

RESULTS

The response rate among patients surveyed was 64%. Of the 43 respondents (48%) who reported abuse, 17 (40%) cited childhood abuse, 12 (28%) cited adulthood abuse, and 14 (33%) cited repeated abuse. Women describing long-term abuse reported a significantly greater number of physical, pain, and anxiety symptoms and were more likely to report a history of substance abuse than women reporting abuse during childhood or adulthood alone.

CONCLUSIONS

These data indicate a significant association between health status and reported abuse among women presenting to a multidisciplinary pain center for pain management. This finding is consistent with those of previous investigators, and emphasizes the importance of routine evaluation of the presence of long-term abuse as a possible predictor of the onset of chronic pain states.

Determination of pesticides in composite dietary samples by gas chromatography/mass spectrometry in the selected ion monitoring mode by using a temperature-programmable large volume injector with preseparation column

Use of a temperature-programmable preseparation column in the gas chromatographic (GC) injection port permits determination of a wide range of semi-volatile pesticides including organochlorines, organophosphates, triazines, and anilines in fatty composite dietary samples while reducing sample preparation time and solvent consumption. Dietary samples are mixed with diatomaceous earth and are Soxhlet-extracted with an azeotropic solution of hexane and acetone. Sample preparation uses liquid-liquid partitioning over diatomaceous earth followed by normal phase chromatography over partially deactivated alumina. The final cleanup step occurs in a preseparation column in the GC injector, which is able to perform splitless transfer of the analytes to the analytical column and purge 99% of the high molecular weight residue. Detection is performed by GC/mass spectrometry (MS) in the selected ion monitoring mode. Method detection limits were at or below 2 ng/g for 24 of 35 pesticides studied, with recovery between 70 and 125% for 27 pesticides in samples fortified at 10 ng/g. Recovery was not dependent on fat content when measured in laboratory fortified samples containing 1, 5, and 10% fat by weight. Precision over multiple injections was acceptable, with a relative standard deviation of 2.6-15% for 25 analytes.

Do physical and sexual abuse differentially affect chronic pain states in women?

To evaluate the role of physical and/or sexual abuse on chronic pain symptoms and health care utilization in women, 104 consecutive female patients presenting to a multidisciplinary pain center for management of chronic pain were surveyed. Outcomes included a measure of sexual or physical abuse history (Drossman Sexual-Physical Abuse Survey), and measures of anxiety, health care utilization, substance abuse, and somatic symptoms. Forty-eight percent of the sample reported a history of physical abuse (PA) or sexual abuse (SA). Forty percent of the abused patients reported both PA and SA and the remainder reported SA (37%) or PA (23%) alone. The women who reported abuse had increased pain, physical symptoms, anxiety symptoms, and mental health care utilization compared to nonabused women. The women who reported abuse were also more likely to smoke and abuse street drugs. Women who reported both PA and SA were more likely to report head pain when compared to those who reported only PA or SA. Given the impact of abuse, particularly SA, on the presentation of chronic pain, queries regarding abuse should become a routine component of the patient interview. Abused patients should be referred to mental health care practitioners as a component of successful pain management if unresolved issues persist.

HIV infection in hospitalized patients and Medicaid enrollees: the accuracy of medical record coding

To evaluate the accuracy of computerized medical-record coding for human immunodeficiency virus (HIV), medical charts were reviewed in six sites. In 7601 hospital and 867 Medicaid records with a listed diagnosis of HIV, the predictive value for HIV was 91% or higher. HIV was identified in 34% of 1155 Medicaid records listing immune disorder or illness in the acquired immunodeficiency syndrome (AIDS) surveillance definition (without an HIV code). In hospital and Medicaid records, AIDS was identified both in records listing AIDS and records listing HIV without AIDS. HIV codes on hospital and Medicaid records were highly predictive for HIV; undercoding of HIV occurred in Medicaid records.

The completeness of AIDS case reporting, 1988: a multisite collaborative surveillance project

OBJECTIVES

The purpose of this study was to evaluate the completeness of acquired immunodeficiency syndrome (AIDS) case reporting.

METHODS

Statewide or hospital-specific 1988 medical records were linked with AIDS surveillance in six sites. Medical records were reviewed for persons who had diagnoses suggesting human immunodeficiency virus (HIV) infection or AIDS but were not reported to AIDS surveillance by September 1989.

RESULTS

Among 4500 hospitalized persons diagnosed with AIDS through 1988 in the six sites, completeness of reporting was 92% (95% CI = 89%, 96%; range across sites = 89% to 97%). Completeness of reporting was high in males (92%), females (95%), Whites (95%), Blacks (90%), Hispanics (92%), men reporting sexual contact with men (92%), persons reporting injecting-drug use (91%), and persons exposed to HIV through heterosexual contact (99%). In Medicaid enrollees (two states), completeness of reporting was 99% (95% CI = 95%, 99%) in inpatients and 90% (95% CI = 79%, 90%) in outpatients. Of previously reported persons with AIDS, 82% were reported within 5 months of diagnosis.

CONCLUSIONS

Completeness of AIDS reporting was high, overall and in each major demographic and HIV exposure group. These results demonstrate that current surveillance data in these six sites provide timely and accurate information regarding persons with AIDS.

Sexual practices in the transmission of hepatitis B virus and prevalence of hepatitis delta virus infection in female prostitutes in the United States

OBJECTIVE

To evaluate heterosexual transmission of hepatitis B virus (HBV) and the prevalence of hepatitis delta virus (HDV) infection in female prostitutes.

DESIGN

Survey.

SETTING

Sexually transmitted disease clinics, drug treatment programs, detention centers, and/or outreach efforts in eight areas in the United States.

PARTICIPANTS

A total of 1368 female prostitutes 18 years of age or older.

OUTCOME MEASURES

Seropositivity for HBV and HDV infection.

RESULTS

The overall prevalence of past or present HBV infection was 56%: 74% in women who were injecting-drug users (IDUs), 38% in women reporting no history of injecting-drug use (non-IDUs), 51% in whites, 55% in blacks, and 67% in Hispanics. Of 21 HBV carrier IDUs, 21% had HDV infection; of 18 HBV carrier non-IDUs, 6% had HDV infection. In non-IDUs (49%), risk factors for HBV infection were a history of having penile-anal intercourse (odds ratio [OR], 3.1; 95% confidence limits [CL], 1.3, 7.3) and seropositivity for syphilis and human immunodeficiency virus (HIV) infection. In IDUs, factors associated with an increased risk of infection, in addition to behaviors related to injecting-drug use, were the number of lifetime sexual partners, having sexual partners from groups at high risk for HBV infection, and seropositivity for syphilis and HIV infection; spermicide and/or diaphragm use was associated with a markedly decreased risk of HBV infection among blacks (OR, 0.1; 95% CL, 0.03, 0.4) and Hispanics (OR, 0.2; 95% CL, 0.06, 0.9).

CONCLUSION

This is the first study to suggest that having anal intercourse and failing to use vaginal contraceptives may facilitate transmission of HBV to women. Our data support guidelines that recommend hepatitis B vaccination for prostitutes and persons with a history of sexually transmitted diseases or multiple sexual partners.

Synthesis of albumin and acute-phase proteins in perfused liver after burn injury in rats

The acute-phase response that follows injury and sepsis is characterized by increased hepatic synthesis of specific secreted proteins while production of albumin is decreased. The effect of burn injury on specific synthesis rates of secreted hepatic proteins has not been reported. In this study, Sprague-Dawley rats received either a 30% flame burn (n = 12) or a sham burn (n = 12) and were allowed to recover for 11 days. Burned animals showed slower weight gains and a 25% to 30% higher resting energy expenditures compared with controls. On postburn day 11, synthesis of secreted hepatic proteins was measured by incorporation of leucine during a 2-hour isolated liver perfusion. Synthesis of total secreted proteins, the seromucoid fraction, and complement component C3 was significantly increased in burned animals, whereas synthesis of albumin was unaltered. In spite of unchanged albumin synthesis, plasma albumin concentrations were 50% lower in burned animals than in control animals throughout the postburn period. These findings suggest that decreased albumin synthesis is not the only mechanism responsible for persistent hypoalbuminemia that follows burn injury.

Increased synthesis of secreted hepatic proteins during abdominal sepsis

To study the effect of intraabdominal sepsis on hepatic protein synthesis, male Sprague-Dawley rats underwent celiotomy with either cecal ligation and puncture (CLP) or sham operation. Eight and sixteen hours later total hepatic protein synthesis was measured by flooding dose technique. Specific synthetic rates of structural or secreted hepatic proteins were further studied 16 hr after CLP in an isolated perfused liver model. Total hepatic protein synthesis was significantly elevated at 16 hr (59 +/- 6%/day vs 37 +/- 6%/day, P less than 0.05), but not 8 hr post-CLP. Structural hepatic protein synthesis was unchanged after CLP; however, the synthetic rates of the acute-phase secretory proteins alpha 1-acid glycoprotein, transferrin and complement component C3 were significantly increased 16 hr after CLP. However, the albumin synthetic rate was not increased during sepsis. We conclude that sepsis causes augmentation of hepatic protein synthesis primarily to increase acute-phase proteins for host defense.

Static depiction of movement

A number of pictorial devices were compared in order to assess their relative effectiveness in depicting events. Effectiveness, as measured by a rating task, did not seem to be a function of the classification of a device as natural or metaphorical. Rather, it depended on whether a given device highlighted a distinctive aspect of a particular event (running, jumping, or moving), or simply modified the event. This observation was buttressed by the existence in a forced-choice task of a category boundary for depictions of running (pictures with a certain device were seen as running, those without it were not) but not for moving or jumping. Even preschool children displayed some understanding of metaphorical devices. They chose figures with those devices as running faster than the experimental standard. Results are discussed in the context of Kennedy's characterization of pictorial metaphors and Gibson's framework for understanding the relationship between pictorial and environmental information.

Does silence simply separate speech components?

A study was conducted to test one possible acoustic explanation of one role played by silent intervals in the perception of stop consonants. We hypothesized that silence creates a separation between the different components of a speech stimulus, thus reducing the magnitude of the auditory interaction between the stimulus components. In order to test this auditory separation hypothesis, we attempted to trade silence against an auditory separation based upon the selective lateralization of the stimulus components created by an interaural phase shift. In finding no such trading relation, we failed to support the auditory separation hypothesis.