Viability of the rectus femoris muscle flap for groin wound coverage after ligation of proximal inflow

Lower extremity revascularization via groin incisions can be complicated by wound dehiscence associated with infection, seroma and femoral vessel exposure. This may require additional surgical debridement and coverage of vascular structures and grafts. The pedicled rectus femoris muscle flap (RFF) has both bulk and a large arc of rotation, making it useful for reconstruction. Its main pedicle is the descending branch of the lateral femoral circumflex artery (DLFCA), a branch of the profunda femoris artery. One could anticipate that ligation of more proximal vasculature could lead to ischemia of the RFF. We present two patients who each underwent vascular surgery involving the common femoral artery and subsequent reconstruction utilizing a pedicled RFF. Both patients then required additional vascular procedures involving the ligation of inflow vessels proximal to the DLFCA. The flaps remained viable, demonstrating the rich collateralization of blood supply that occurs in vascular disease patients.

Acute lung injury: how to stabilize a broken lung

The pathophysiology of acute respiratory distress syndrome (ARDS) results in heterogeneous lung collapse, edema-flooded airways and unstable alveoli. These pathologic alterations in alveolar mechanics (i.e. dynamic change in alveolar size and shape with each breath) predispose the lung to secondary ventilator-induced lung injury (VILI). It is our viewpoint that the acutely injured lung can be recruited and stabilized with a mechanical breath until it heals, much like casting a broken bone until it mends. If the lung can be "casted" with a mechanical breath, VILI could be prevented and ARDS incidence significantly reduced.

Abstract P4-01-06: The Role of the PI3K/AKT, RAS/MAPK and Novel Signaling Pathways in Resistance to HER2-Targeted Therapy

Despite the proven clinical benefits of HER2-targeted therapy, resistance to trastuzumab and lapatinib exists. Understanding the molecular mechanisms responsible for resistance is critical to improving the survival rates of patients with this aggressive subtype of breast cancer. Currently, there are no clinically validated biomarkers of resistance to therapy. To address this issue, we measured the responses of a panel of 18 HER2-amplified breast cancer cell lines to both trastuzumab and lapatinib and evaluated the activity of PI3K/AKT/mTOR and RAS/MAPK/ERK signaling in resistance. Eight of the cell lines were identified as resistant to trastuzumab and seven as resistant to lapatinib by both two and three dimensional response assays. Five of the trastuzumab resistant cell lines remained sensitive to lapatinib (IC50 < 1 μM), indicating that these two agents have at least partially non-overlapping mechanisms of resistance. The combination of low PTEN or the presence of activating mutations of PI3K, and thus increased activity of PI3K/AKT signaling, is a strong predictor of resistance to trastuzumab. However, this is not the case with lapatinib, two of the cell lines with activating mutations of PI3K (MDA-361 and HCC-202) were resistant to lapatinib whereas two other PI3K mutant cells lines (SUM-190 and HCC-1954) were lapatinib sensitive, indicating that lapatinib resistance can occurindependently of increased PI3K/AKT signaling. To further investigate these mechanisms, we measured the effects of trastuzumab and lapatinib treatment on AKT/mTOR and ERK activation. Cell lines sensitive to trastuzumab or lapatinib showed a marked reduction in pAKT, pS6K and pERK in response to either agent, whereas the resistant cells maintained high pAKT, pS6K and pERK levels in the presence of trastuzumab and lapatinib. In cell lines resistant to trastuzumab yet sensitive to lapatinib, treatment with lapatinib significantly reduced the phosphorylation of AKT, S6K and ERK. Thus in a subpopulation of cell lines lapatinib can overcome trastuzumab resistance via continued deactivation of PI3K/AKT/mTOR and MAPK/ERK signaling. However, there still remains a subgroup of HER2-positive cells that are resistant to both trastuzumab and lapatinib. We used global expression analysis by both mRNA microarray and proteomic screening to identify a set of genes and proteins that are consistently altered in these innately resistant cells relative to the sensitive cell lines. In vitro validation of these targets will reveal which are playing a functional role in resistance and are thus potentially druggable targets to be used in improving the survival of patients with HER2-positive disease.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-01-06.

The public health surveillance of asthma

Asthma is a highly prevalent disease that affects the quality of life of many people in the United States. Yet there is limited descriptive epidemiological understanding of the disease, particularly at the state and local levels. Minimal surveillance of asthma is occurring across the country. Surveillance of a disease requires that public health workers have the ability to accurately identify cases, have access to needed data, and have adequate resources so that they can collect, assess, report, and use the data-all considerable challenges in the case of asthma. We consider four groups of questions that asthma surveillance should address: (1) How much asthma is there and what are the trends in asthma occurrence over time? (2) How severe is the asthma and what are the trends in asthma severity over time? (3) How well is asthma controlled and what are the trends in asthma management over time? (4) What is the cost of asthma? Because wise decision making in public health depends on the availability of appropriate data for program planning, implementation, and evaluation, we encourage increased surveillance of asthma in jurisdictions across the country.

Use of a two-hybrid system to identify mutations in Max that confer increased affinity for Myc

A yeast two-hybrid system was used to identify mutants of Max that exhibit an increased affinity for Myc. Truncated forms of the Max helix-loop-helix/leucine zipper motif (HLH/Zip) were first expressed in a two- hybrid system in which the bait protein was the HLH/Zip motif of Myc. Deletion of amino acids both amino-terminal and carboxy-terminal to the leucine zipper of Max reduced Myc/Max heterodimer formation as evidenced by a 160-fold reduction in the expression of the lacZ gene. A library of partially randomized sequences encoding this minimal leucine zipper of Max was then screened using the two-hybrid system. Mutant forms of the Max leucine zipper were identified whose affinities for Myc, as measured by beta-galactosidase activity in yeast lysates, were from 8- to 200-fold greater than the wild-type Max zipper. These Max mutants were shown to interact specifically with Myc and not with wild-type Max. Of 29 mutants analyzed, all had a unique amino acid sequence. This result illustrates the value of a genetic screen in the identification of a collection of mutant forms of the Max leucine zipper whose structures would not have been predicted based on principles of structure-based design.

An epidemiologic study of fatigue with relevance for the chronic fatigue syndrome

We surveyed households in four rural Michigan communities to confirm a reported cluster of cases resembling chronic fatigue syndrome (CFS) and to study the epidemiology of fatigue in a rural area. Data were collected from 1698 households. We did not confirm the reported cluster. The prevalence of households containing at least one fatigued person was similar between communities thought to harbor the cluster and communities selected for comparison. Symptoms and features of generic forms of fatigue were very similar to those often attributed to CFS.

The effects of different percentages of dietary fat intake, exercise, and calorie restriction on body composition and body weight in obese females

PURPOSE

The goal of this study was to determine the effect of varying the amount of dietary fat, while holding calories at 1,200 kcals/day, on body weight and percent body fat in 35 obese women.

DESIGN

A pretest, midtest, posttest experimental design was employed, and subjects were randomly divided into one of four dietary fat groups, with 10%, 20%, 30%, or 40% of caloric intake as dietary fat.

INTERVENTION

Subjects consumed 1,200 kcals/day and a specified percentage of total energy as fat, depending on their dietary group. Protein was held constant at 20%. All subjects engaged in a five day/week walking program.

SETTING

Participants were recruited from the general community using newspaper advertisements.

SUBJECTS

Thirty-five obese women 25 to 45 years of age (means=38 +/- 4.97) served as subjects. All were at least 20% above ideal weight and 30% to 52% body fat.

MEASURES

Percent body fat, body weight, and anthropomorphic measurements were taken at baseline, six and 12 weeks. Dietary intake was recorded daily by each subject, and exercise walking logs were maintained by each participant.

RESULTS

All subjects lost body weight and body fat; however, there were no significant differences in the rate or amount of body weight or percent body fat lost across the four groups during the intervention.

CONCLUSIONS

It appears that during calorie restriction and exercise for 12 weeks, percent of calories derived from dietary fats does not influence loss of body weight or percent body fat in adult obese women.

Characterization of a Max:DNA complex by cross-linking to photoactive oligonucleotides

The structure of the Max:DNA complex was investigated by cross-linking Max to a series of photoactive oligonucleotides. A single photoactive aryl azide was introduced into oligonucleotides at defined positions downstream from the specific CACGTG binding site. Purified Max homodimers bound to and were cross-linked to oligonucleotides containing a photoactive group either 2, 5, 8, or 11 bp downstream from the binding site. Further analysis revealed that an amino-terminal chymotryptic peptide of Max was cross-linked to the oligonucleotide containing a photoactive probe 11 bp downstream from the specific binding site. This result is consistent with the recent crystal structure of the Max:DNA complex (Ferré-D'Amaré et al., 1993) and further suggests that amino acid residues near the amino-terminus of Max are in close proximity to a region of DNA that is separated from the core binding site by one turn of the double helix.

Why is life stress ignored in studies of 'stress' and athletic performance?

Investigations of relationships between stress and athletic performance and stress and outcomes outside of sport psychology have a parallel evolution. Each area has advanced from early attempts to find simple, strong relationships to current strategies for evaluating the influences of individual differences and situational factors on more elusive relationships. However, the most common conceptualizations of stress are very different in research on sport psychology and stress, and most studies of stress and athletic performance do not involve the influences of stress outside athletics. We propose that the approaches used by sports psychologists and stress researchers could be combined to evaluate more fully the relationships between stress and athletic performance.

Influences of stress and situation-specific mastery beliefs and satisfaction with social support on well-being and academic performance

The present study examined the effects of stress and cumulative situation-specific mastery beliefs and satisfaction with social support on somatic and psychological symptomatology and academic performance of 146 college men. Stress was directly related to increased symptomatology and decreased grade point average, whereas mastery beliefs were directly associated with reduced depression and anxiety. Satisfaction with social support was related to anxiety through an interaction with mastery. Neither mastery nor satisfaction with support appeared to act as a stress-buffer through a statistical interaction with stress to moderate effects of high stress. However, earlier analysis of some of the same data showed that total stress, the best predictor of each outcome in this study, was reduced by the combination of strong situation-specific mastery beliefs and high satisfaction with support for subjects who faced many stressors. The combined findings show that situation-specific mastery beliefs reduced appraisal of stress and were associated with better psychological adjustment.

Nutritional balance studies of VLBW infants fed their mothers' milk fortified with a liquid human milk fortifier

This article reports the results of a study designed to compare human milk fortified with a liquid human milk fortifier to a preterm infant formula by analyzing the metabolic balances of certain nutrients when these milks are fed to premature infants. Ten very low birth weight (VLBW) infants were studied during 4-day equilibration periods, then 4-day metabolic balances of N, fat, Ca and P, while each consumed a 1:1 mixture of a pool of its own mother's milk and the liquid human milk fortifier (HM/LF). For comparison, another 10 VLBW infants were studied in similar fashion while consuming the preterm infant formula (PF). Percent nitrogen retentions were 77 +/- 4% (+SD) and 79 +/- 4%, and fat absorptions were 94 +/- 7% and 92 +/- 5% in the HM/LF and PF groups, respectively, and did not differ between the groups. Calcium retention was 86 +/- 21 mg/kg/day (51 +/- 12%) in the HM/LF group and 104 +/- 43 mg/kg/day (45 +/- 19%) in the PF group. The percent Ca retentions did not differ. Phosphorus retentions were 56 +/- 7 mg/kg/day (67 +/- 9%) and 77 +/- 18 mg/kg/day (61 +/- 14%) in the HM/LF and PF groups, respectively. Increases in weight, length, and occipitofrontal circumference (OFC) were similar and normal in both groups. We conclude that VLBW infants fed the HM/LF, mixed 1:1 with their mothers' milk, had rates of absorption and retention of Ca, P, N, and fat similar to rates found in the concurrent study of VLBW infants fed a commercially available PF.

Effects of left ventricular venting and distention during heterogenous distribution of cardioplegic solution

The effects of left ventricular venting and distention on myocardial protection during heterogenous distribution of cardioplegic solution remain undefined. This study was undertaken to determine if left ventricular venting enhances and distention impairs myocardial cooling and recovery of global and regional left ventricular function. Twenty-one pigs were placed on cardiopulmonary bypass and subjected to 80 minutes of ischemic arrest with the mid-left anterior descending artery occluded. Hearts were protected with multidose potassium (25 mEq/L) crystalloid cardioplegic solution supplemented with topical (4 degrees C) and systemic (28 degrees C) hypothermia. During arrest, the left ventricle was vented in seven pigs, seven pigs were not vented, and seven others had systemic pump blood infused into the left ventricle to maintain an end-diastolic pressure of 15 mm Hg. Parameters measured included left ventricular temperature, stroke work index, compliance (end-diastolic pressure-end-diastolic volume curves) and wall motion scores (two-dimensional echocardiography). Distended hearts had the lowest mean left ventricular temperature beyond the left anterior descending arterial occlusion (10.1 degrees +/- 1.8 degrees C distended [p less than 0.025 from vented and nonvented groups] versus 14.2 degrees +/- 0.7 degrees C vented versus 15.5 degrees +/- 1.2 degrees C nonvented), the highest postischemic stroke work index (0.78 +/- 0.09 gm-m/kg distended versus 0.62 +/- 0.07 gm-m/kg vented versus 0.66 +/- 0.07 gm-m/kg nonvented at end-diastolic pressure = 10 mm Hg), and the best wall motion scores (0.7 +/- 0.04 distended [p less than 0.025 from vented and nonvented groups] versus 5.5 +/- 1.80 vented versus 4.8 +/- 1.20 nonvented). Postischemic end-diastolic pressure-end-diastolic volume curves were unchanged from preischemic values in each group. We conclude that during heterogenous cardioplegic arrest, left ventricular venting offers no additional myocardial protection and may negate the beneficial effects of moderate (end-diastolic pressure = 15 mm Hg) left ventricular distention.

Determinants of discharge following coronary artery bypass graft surgery

The optimal time for discharge following coronary artery bypass graft (CABG) surgery is uncertain and varies among institutions. This study was undertaken to determine what factors may discriminate between early and late discharge following surgery. In 177 consecutive patients undergoing isolated CABG procedures, three groups were formed retrospectively according to the number of days hospitalized post CABG: group 1, less than or equal to 8; group 2, 9 to 11; group 3, greater than or equal to 12. Parameters found to discriminate between group 1 and group 3 (p less than .05; chi square analysis) included female sex, unstable angina, congestive heart failure (CHF), age greater than or equal to 65 years, and the development of major postoperative complications. Angina class, prior myocardial infarction, extent of coronary artery disease, aortic cross-clamp time, number of bypass grafts, ejection fraction less than 40 percent, or "minor" postoperative complications were not different among groups. Patients discharged less than or equal to 8 days following CABG had no increase in return visits or readmissions less than 60 days post CABG. We conclude that while certain patients can be safely discharged less than or equal to 8 days post CABG, patients who are female, greater than or equal to 65 years, have unstable angina, CHF, or a major postoperative complication are likely to be hospitalized longer.

Lifetime prevalence of psychiatric disorders in women with perimenstrual difficulties

Fifty-eight women age 30-40 years, blind to the purpose of the study were segregated according to whether they reported none-mild or moderate-severe perimenstrual difficulties on screening interview. Lifetime prevalence of major psychiatric disorders was ascertained using the Diagnostic Interview Schedule. Women in the moderate-severe group (n = 29) showed a significantly greater lifetime prevalence of affective disorders and drug abuse. No cases of somatization disorder were detected in either group.

The filling-in illusion and moving visual phantoms

A new visual illusion, filling-in illusion, is reported and compared to the moving visual phantoms of Tynan and Sekuler (1975). 169 unrelated, unpaid, volunteer subjects were recruited from students and faculty and classified as filling-in positive--able to perceive the illusion, or filling-in negative--unable to perceive it. Other investigations examined the effects of light levels, moving vs static test figures, and black-and-white vs shaded figures. A polaroid study suggests a central rather than retinal location of the illusory effect. Filling-in is a contour completion effect, as are moving visual phantoms. Although a number of differences between the two phenomena exist, it is suggested that they may be due to different aspects of a common mechanism.

Effects of lingual anesthetization upon lingualabial coarticulation

(Right to Left) and (Left to Right) coarticulation of vowels with stop consonants in VCV logotemes was studied before and during oral anesthetization. Correlational analysis revealed that neither LR nor RL coarticulation was markedly reduced in extent, suggesting that orosensory feedback was not crucial to control of coarticulation. This lends support to the notion of central control of coarticulation.

An acoustic-articulatory description of children's defective /s/ productions

The /s/ production of six /s/-defective children and two normal controls were subjected to spectrographic analysis. Articulatorily, two of the children were dentalizers, two had lateral emission of friction, and two were of an "other" type. Results show for normals an /s/ spectrum which is compact (5-11 kHz), powerful, and dominated by strong, sharp spectral peaks at 6 and 10 kHz. Their spectra were context sensitive. Dental subjects showed flatter, less peaked, higher frequency (6-12 kHz), and less intense noise spectrum, which was not so context sensitive. Lateral /s/ subjects showed a broad 4-9 or 4-10 kHz spectrum characterized by somewhat smaller, more numerous peaks, and a lower cutoff frequency (about 4kHz) than for normals. The "other /s/ defectives varied very widely, so that no consistent pattern emerged. The acoustic data are then discussed in terms of the articulation of varieties of friction noise.

Breast-milk monitoring to measure Michigan's contamination with polybrominated biphenyls

In 1973 and 1974, several thousand Michigan dairy farms were contaminated by polybrominated biphenyls (P.B.B.) as the result of an industrial accident. An unknown quantity of contaminated meat and dairy products entered the food chain before contaminated farms were quarantined. To determine the extent of human exposure, P.B.B. concentrations were measured in human breast milk, which was collected in a random-sample survey from nursing mothers throughout Michigan. 96% of 53 samples from Michigan's lower peninsula and 43% of 42 samples from the less densely populated upper peninsula contained detectable levels of P.B.B. These data indicate that about 8 million of Michigan's 9.1 million residents have detectable body burdens of P.B.B.