MT1-MMP-dependent neovessel formation within the confines of the three-dimensional extracellular matrix

During angiogenesis, endothelial cells initiate a tissue-invasive program within an interstitial matrix comprised largely of type I collagen. Extracellular matrix–degradative enzymes, including the matrix metalloproteinases (MMPs) MMP-2 and MMP-9, are thought to play key roles in angiogenesis by binding to docking sites on the cell surface after activation by plasmin- and/or membrane-type (MT) 1-MMP–dependent processes. To identify proteinases critical to neovessel formation, an ex vivo model of angiogenesis has been established wherein tissue explants from gene-targeted mice are embedded within a three-dimensional, type I collagen matrix. Unexpectedly, neither MMP-2, MMP-9, their cognate cell-surface receptors (i.e., β₃ integrin and CD44), nor plasminogen are essential for collagenolytic activity, endothelial cell invasion, or neovessel formation. Instead, the membrane-anchored MMP, MT1-MMP, confers endothelial cells with the ability to express invasive and tubulogenic activity in a collagen-rich milieu, in vitro or in vivo, where it plays an indispensable role in driving neovessel formation.

Gender Differences in Experimental Aortic Aneurysm Formation

Objective— It is hypothesized that a male predominance, similar to that in humans, persists in a rodent model of experimental abdominal aortic aneurysm (AAA) via alterations in matrix metalloproteinases (MMPs).

Methods and Results— Group I experiments were as follows: elastase perfusion of the infrarenal aorta was performed in male (M) and female (F) rats. At 14 days, aortas were harvested for immunohistochemistry, real-time polymerase chain reaction (PCR), and zymography. Group II experiments were the following: abdominal aorta was transplanted from F or M donors into F or M recipients. At 14 days, rodents that had undergone transplantation underwent elastase perfusion. In group III, male rats were given estradiol or sham 5 days before elastase perfusion. In group I, M rats had larger AAAs with higher frequency than did F rats. M rat aortas had more significant macrophage infiltrates and increased matrix metalloproteinase (MMP)-9 production and activity. In group II, M-to-M aortic transplants uniformly developed aneurysms after elastase perfusion, whereas F-to-F aortic transplants remained resistant to aneurysm formation. F aortas transplanted into M recipients, however, lost aneurysm resistance. In group III, estradiol-treated rats demonstrated smaller aneurysms and less macrophage infiltrate and MMP-9 compared with M controls after elastase.

Conclusions— These data provide evidence of gender-related differences in AAA development, which may reflect an estrogen-mediated reduction in macrophage MMP-9 production.

Blasts from the past

With this issue of the JCI, we celebrate the 80th anniversary of the Journal. While 80 years is not a century, we still feel it is important to honor what the JCI has meant to the biomedical research community for 8 decades. To illustrate why the JCI is the leading general-interest translational research journal edited by and for biomedical researchers, we have asked former JCI editors-in-chief to reflect on some of the major scientific advances reported in the pages of the Journal during their tenures.

EZH2 is a marker of aggressive breast cancer and promotes neoplastic transformation of breast epithelial cells

The Polycomb Group Protein EZH2 is a transcriptional repressor involved in controlling cellular memory and has been linked to aggressive prostate cancer. Here we investigate the functional role of EZH2 in cancer cell invasion and breast cancer progression. EZH2 transcript and protein were consistently elevated in invasive breast carcinoma compared with normal breast epithelia. Tissue microarray analysis, which included 917 samples from 280 patients, demonstrated that EZH2 protein levels were strongly associated with breast cancer aggressiveness. Overexpression of EZH2 in immortalized human mammary epithelial cell lines promotes anchorage-independent growth and cell invasion. EZH2-mediated cell invasion required an intact SET domain and histone deacetylase activity. This study provides compelling evidence for a functional link between dysregulated cellular memory, transcriptional repression, and neoplastic transformation.

Matrilysin-dependent elastolysis by human macrophages

Human macrophages found in juxtaposition to fragmented elastin in vivo express the elastolytic matrix metalloproteinases (MMPs) progelatinase B, prometalloelastase, and promatrilysin. Though MMPs can degrade a range of extracellular matrix components, increasing evidence suggests that preferred targets in vivo include nonmatrix substrates such as chemokines and growth factors. Hence, the means by which MMPs participate in elastin turnover remain undefined as does the identity of the elastolysins. Herein, human macrophage cultures have been established that express a complement of elastolytic proteinases similar, if not identical, to that found in vivo. Under plasminogen-free conditions, macrophages preferentially use metalloelastase to mediate elastolysis via a process that deposits active enzyme on elastin surfaces. By contrast, in the presence of plasminogen, human macrophages up-regulate proteolysis 10-fold by processing promatrilysin to an active elastolysin via a urokinase-type plasminogen activator-dependent pathway. Matrilysin-deficient human macrophages fail to mediate an elastolytic response despite the continued expression of gelatinase B and metalloelastase. Thus, acting in concert with cosecreted cysteine proteinases whose activities are constrained to sites of macrophage-elastin contact (Punturieri, A., S. Filippov, E. Allen, I. Caras, R. Murray, V. Reddy, and S.J. Weiss. 2000. J. Exp. Med. 192:789-799), matrilysin confers macrophages with their most potent MMP-dependent elastolytic system.

Membrane type I matrix metalloproteinase usurps tumor growth control imposed by the three-dimensional extracellular matrix

Cancer cells are able to proliferate at accelerated rates within the confines of a three-dimensional (3D) extracellular matrix (ECM) that is rich in type I collagen. The mechanisms used by tumor cells to circumvent endogenous antigrowth signals have yet to be clearly defined. We find that the matrix metalloproteinase, MT1-MMP, confers tumor cells with a distinct 3D growth advantage in vitro and in vivo. The replicative advantage conferred by MT1-MMP requires pericellular proteolysis of the ECM, as proliferation is fully suppressed when tumor cells are suspended in 3D gels of protease-resistant collagen. In the absence of proteolysis, tumor cells embedded in physiologically relevant ECM matrices are trapped in a compact, spherical configuration and unable to undergo changes in cell shape or cytoskeletal reorganization required for 3D growth. These observations identify MT1-MMP as a tumor-derived growth factor that regulates proliferation by controlling cell geometry within the confines of the 3D ECM.

Matrix metalloproteinases (MMPs) regulate fibrin-invasive activity via MT1-MMP-dependent and -independent processes

Cross-linked fibrin is deposited in tissues surrounding wounds, inflammatory sites, or tumors and serves not only as a supporting substratum for trafficking cells, but also as a structural barrier to invasion. While the plasminogen activator-plasminogen axis provides cells with a powerful fibrinolytic system, plasminogen-deleted animals use alternate proteolytic processes that allow fibrin invasion to proceed normally. Using fibroblasts recovered from wild-type or gene-deleted mice, invasion of three-dimensional fibrin gels proceeded in a matrix metalloproteinase (MMP)-dependent fashion. Consistent with earlier studies supporting a singular role for the membrane-anchored MMP, MT1-MMP, in fibrin-invasive events, fibroblasts from MT1-MMP-null mice displayed an early defect in invasion. However, MT1-MMP-deleted fibroblasts circumvented this early deficiency and exhibited compensatory fibrin-invasive activity. The MT1-MMP-independent process was sensitive to MMP inhibitors that target membrane-anchored MMPs, and further studies identified MT2-MMP and MT3-MMP, but not MT4-MMP, as alternate pro-invasive factors. Given the widespread distribution of MT1-, 2-, and 3-MMP in normal and neoplastic cells, these data identify a subset of membrane-anchored MMPs that operate in an autonomous fashion to drive fibrin-invasive activity.

Regulation of membrane-type matrix metalloproteinase 1 activity by dynamin-mediated endocytosis

Membrane-type matrix metalloproteinase 1 (MT1-MMP) plays a critical role in extracellular matrix remodeling under both physiological and pathological conditions. However, the mechanisms controlling its activity on the cell surface remain poorly understood. In this study, we demonstrate that MT1-MMP is regulated by endocytosis. First, we determined that Con A induces proMMP-2 activation in HT1080 cells by shifting endogenous MT1-MMP from intracellular compartments to cell surface. This phenotype was mimicked by the cytoplasmic truncation mutant MT1 Delta C with more robust pro-MMP-2 activation and cell surface expression than wild-type MT1-MMP in transfected cells. MT1 Delta C was subsequently shown to be resistant to Con A treatment whereas MT1-MMP remains competent, suggesting that Con A regulates MT1-MMP activity through cytoplasmic domain-dependent trafficking. Indeed, MT1-MMP was colocalized with clathrin on the plasma membrane and with endosomal antigen 1 in endosomes. Internalization experiments revealed that MT1-MMP is internalized rapidly in clathrin-coated vesicles whereas MT1 Delta C remains on cell surface. Coexpression of a dominant negative mutant of dynamin, K44A, resulted in elevation of MT1-MMP activity by interfering with the endocytic process. Thus, MT1-MMP is regulated by dynamin-dependent endocytosis in clathrin-coated pits through its cytoplasmic domain.

Creative arterial bypass grafting can be performed on the beating heart

BACKGROUND

To demonstrate that compromise is unnecessary in either the design or performance of beating heart surgery, we report our experience, over 1 year, of total arterial revascularization where composite or creative grafting was utilized.

METHODS

We performed 321 off-pump coronary artery bypass operations, of which, 290 (90%) were done with only arterial conduits. The mean number of distal anastomoses was 2.48, with a range of 1 to 5. There were no aortic anastomoses. One hundred eighty-nine patients (65%) were male, and 101 (35%) were female, with a mean age of 67 years. Comorbidities included chronic renal failure (CRF), 21 (7%); diabetes, 92 (32%); obesity, 68 (23%); hypertension, 212 (73%); chronic obstructive pulmonary disease, 189 (65%); cerebral vascular accident (CVA), 39 (13%); smoking, 164 (56%); and hypercholesterolemia, 151 (52%). The mean ejection fraction was 56%, with a range of 21% to 71%. All procedures were performed with external stabilizers with or without vacuum assist. The complete arterial revascularizations included a T-graft (internal thoracic [ITA]/radial arteries [RA]), 130 (45%); a sequential graft (ITA +/- RA), 118 (41%); a U-graft (coronary-coronary graft perfused by the ITA or right gastroepiploic artery), 5 (2%); an I-graft (ITA/RA), 4 (1%); an X-graft (ITA/RA), 2 (12); and a Y-graft (ITA/RA), 31 (10%).

RESULTS

The postoperative incidence of atrial fibrillation was 80 of 290 (27%); CVA, 5 of 290 (2%); bleeding resulting in take-back, 5 of 290 (2%); CRF, 8 of 290 (3%); deep sternal infection, 4 of 290 (1%); and readmission (30-day) for angina, 4 of 290 (1%). The observed perioperative (30-day) mortality was 9 of 290 (3.1%), with the STS predicted rate of 3.82%.

CONCLUSIONS

Our experience indicates that once the operating surgeon has learned to safely expose the lateral and inferior walls of the heart, the type of conduit and the method of revascularization should be no different than that used with cardiopulmonary bypass. However, we still recommend conventional methods of revascularization (on-pump with saphenous vein conduits) for the ischemic patient.

Nitric oxide inhibition increases matrix metalloproteinase-9 expression by rat aortic smooth muscle cells in vitro

OBJECTIVE

The hypothesis to be tested was that diminished bioavailable nitric oxide (NO) affects matrix metalloproteinase (MMP) expression and activation in vascular smooth muscle cells (SMCs).

METHODS

Cultivated rat aortic SMCs (RA-SMCs) were exposed to increasing concentrations of L-N-monomethyl arginine (L-NMMA), a nonselective inhibitor of NO synthase, in the presence of proinflammatory cytokines (50 ng/mL interleukin [IL]-1beta, 50 ng/mL interferon-gamma, and 30 microg/mL lipopolysaccharide). Nitrite and nitrate, two of the final end products of NO metabolism, were measured in media collected at 48 hours with the use of the Saville assay (n = 4). MMP activity was measured with 1% gelatin zymography (n = 4). In separate experiments in which 2 ng/mL of IL-1beta and L-NMMA was used, MMP protein and messenger RNA (mRNA) levels were determined with Western blot analysis (n = 3) and semiquantitative reverse transcriptase-polymerase chain reaction (n = 3), respectively. Data were analyzed with nonparametric analysis of variance.

RESULTS

Increasing concentrations of the NO synthase inhibitor L-NMMA caused a dose-dependent decrease (P <.05) in nitrite and nitrate production by RA-SMCs after cytokine exposure. Zymography documented an early dosedependent increase (P <.05 compared with cytokines alone) in 92-kd MMP activity, with no significant changes in 72-kd MMP activity after treatment with L-NMMA (P >.05 compared with cytokines alone). Reverse transcriptase-polymerase chain reaction and Western blot analysis revealed that the addition of L-NMMA to IL-1beta-stimulated RA-SMCs led to significant increases in MMP-9 mRNA (n = 3, P <.01 for 1.0 mmol/L L-NMMA) and MMP-9 protein levels (n = 3, P <.05), respectively. No differences in MMP-2 mRNA or protein levels were demonstrated.

CONCLUSIONS

Inhibition of cytokine-induced NO expression in RA-SMCs is associated with a selective, dose-dependent increase in MMP-9 expression and synthesis. These findings suggest that alterations in local NO synthesis may influence MMP-9-dependent vessel wall damage.

Role of stromelysin 1 and gelatinase B in experimental acute lung injury

Matrix metalloproteinases (MMPs) are upregulated locally in sites of inflammation, including the lung. Several MMP activities are upregulated in acute lung injury models but the exact role that these MMPs play in the development of the lung injury is unclear due to the absence of specific inhibitors. To determine the involvement of individual MMPs in the development of lung injury, mice genetically deficient in gelatinase B (MMP-9) and stromelysin 1 (MMP-3) were acutely injured with immunoglobulin G immune complexes and the intensity of the lung injury was compared with genetically identical wild-type (WT) mice with normal MMP activities. In the WT mice there was upregulation of gelatinase B and stromelysin 1 in the injured lungs which, as expected, was absent in the genetically deficient gelatinase B- and stromelysin 1-deficient mice, respectively. In the deficient mice there was little in the way of compensatory upregulation of other MMPs. The gelatinase B- and the stromelysin 1-deficient mice had less severe lung injury than did the WT controls, suggesting that both MMPs are involved in the pathogenesis of the lung injury. Further, the mechanism of their involvement in the lung injury appears to be different, with the stromelysin 1-deficient mice having a reduction in the numbers of neutrophils recruited into the lung whereas the gelatinase B-deficient mice had the same numbers of lung neutrophils as did the injured WT controls. These studies indicate, first, that both gelatinase B and stromelysin 1 are involved in the development of experimental acute lung injury, and second, that the mechanisms by which these individual MMPs function appear to differ.

Predictors of cardiac patients' psychophysiological responses to caregiving

Patients who are hospitalized for treatment of cardiac problems are at risk from life-threatening cardiovascular changes related to autonomic nervous system (ANS) arousal. Physical care during hospitalization can increase ANS arousal, yet caregiving is an essential feature of patient treatment. The purpose of this study was to identify the degree to which a patient's vulnerability to sensory stimuli, perceptions of previous caregiving and stressful events during hospitalization may contribute to ANS arousal during caregiving. Fifty-nine patients, who were hospitalized for treatment of coronary artery or valvular disease, received a standardized protocol designed to simulate aspects of physical caregiving. Heart rate, incidence of arrhythmias, blood pressure and state anxiety were measured during the protocol to determine ANS arousal. Regression analyses provided evidence that sensory vulnerability was the most consistent predictor across all indices of arousal during caregiving. Previous caregiving experiences that were perceived as 'negative' by the patient also contributed to higher blood pressure and anxiety. Stressful hospital events involving the family predicted higher blood pressure during caregiving.

Use, understanding, and beliefs about complementary and alternative medicines among emergency department patients

OBJECTIVES

To describe the extent of complementary and alternative medicine (CAM) use among emergency department (ED) patients, to evaluate patients' understanding of CAMs, and to determine gender differences in beliefs about CAMs.

METHODS

This study was a convenience sampling of patients seen in an urban ED. Patient demographics were recorded. A questionnaire was administered that assessed patients' knowledge and use of CAMs. Patients were also asked about their beliefs on safety, medication interactions, and conveying information about these substances to their physicians.

RESULTS

A total of 350 ED patients were included in the study; 87% had heard of at least one of the CAMs. There was no difference between genders or races concerning knowledge about CAMs. The most commonly known CAMs were ginseng (75%), ginkgo biloba (55%), eucalyptus (58%), and St. John's wort (57%). Forty-three percent of the responders had used CAMs at some time and 24% were presently using CAMs. The most commonly used CAMs were ginseng (13%), St. John's wort (6%), and ginkgo biloba (9%). All CAMs were considered to be safe by 16% of the patients. Only 67% would tell their doctors they were using CAMs. Females were more likely than males to believe that CAMs do not interact with other medications (15% vs 7%, difference 8%, 95% CI = 2% to 15%).

CONCLUSIONS

Complementary and alternative medicines are familiar to most patients and used by many of them. Despite this, a large percentage of patients would not tell their physicians about their use of alternative medications. Emergency medicine providers should be aware of the commonly used CAMs, and questions about their use should be routinely included in ED exams.

Deep hypothermic circulatory arrest: II. Changes in electroencephalogram and evoked potentials during rewarming

BACKGROUND

Electrophysiologic studies during rewarming after deep hypothermic circulatory arrest probe the state of the brain during this critical period and may provide insight into the neurological effects of circulatory arrest and the neurologic outcome.

METHODS

Electroencephalogram (EEG) and evoked potentials were monitored during rewarming in 109 patients undergoing aortic surgery with hypothermic circulatory arrest.

RESULTS

The sequence of neurophysiologic events during rewarming did not mirror the events during cooling. The evoked potentials recovered first followed by EEG burst-suppression and then continuous EEG. The time to recovery of the evoked potentials N20-P22 complex was significantly correlated with the time of circulatory arrest even in patients without postoperative neurologic deficits (r = 0.37, (p = 0.002). The nasopharyngeal temperatures at which continuous EEG activity and the N20-P22 complex returned were strongly correlated (r = 0.44, p = 0.0002; r = 0.41, p = 0.00003) with postoperative neurologic impairment. Specifically, the relative risk for postoperative neurologic impairment increased by a factor of 1.56 (95% CI 1.1 to 2.2) for every degree increase in temperature at which the EEG first became continuous.

CONCLUSIONS

No trend toward shortened recovery times or improved neurologic outcome was noted with lower temperatures at circulatory arrest, indicating that the process of cooling to electrocerebral silence produced a relatively uniform degree of cerebral protection, independent of the actual nasopharyngeal temperature.

A comparison of rural and urban ambulance crashes

Ambulance crashes are a significant safety issue both to the EMTs and to patients transported in the vehicle. Safety issues are dependent on the environment and may be different in rural and urban settings. Ambulance crashes reported to the State EMS bureau during the years of 1993 to 1997 were evaluated. Counties with >250,000 population were considered urban. State population was 2 million urban and 2.8 million rural. Two investigators determined first if the crash was urban or rural. Outcome information was extracted on the degree of injury, citations given, and information on the ambulance and other vehicle condition. In addition, independent variables of weekend versus weekday, day versus night, posted speed, weather, road condition (wet versus dry), intersections, and use of seat belts were extracted. Results were compared using a 2-tailed Chi-square or Fisher's exact with significance at P <.05. Relative risks and 95% confidence intervals were calculated for each variable. There were a total of 183 Ambulance crashes, 115 urban (19/million pop/yr), and 68 rural (8/million pop/yr). Significantly lower percentage of injury crashes occurred in the urban setting (OR = 0. 49, 95% CI = 0.24 to 0.98) with fewer of these considered "severe" (OR = 0.0, 95% CI = 0.0 to 0.73). Citations were more likely to be issued to the urban ambulance driver (OR = 4.95, 95% CI = 1.09 to 45. 70) and the other urban vehicle driver (OR = 3.65, 95% CI = 1.37 to 11.31). However, the urban ambulance was less likely to be damaged (OR = 0.24, 95% CI = 0.10 to 0.55), disabled (OR = 0.41, 95% CI = 0. 20 to 0.84), or towed (OR = 0.40, 95% CI = 0.20 to 0.83). In the urban setting fewer vehicles were traveling in areas with posted speeds >54 mph (OR = 0.24, 95% CI = 0.06 to 0.78) and nonrestrained people were less likely to be injured (OR = 0.28, 95% CI = 0.06 to 1. 25). For injured persons there was no difference in independent variables in the urban versus rural settings. Although the rate of ambulance injuries was greater in the urban environment, the severity of the injuries was worse in the rural environments where crashes occurred at higher posted speeds. In the rural setting nonrestrained passengers were more likely to be injured.

Visits to home environments by emergency medical services: a statewide study

Understanding out-of-hospital transport demographics would clarify the opportunities for injury surveillance and prevention.

OBJECTIVE

To test the hypotheses that there are demographic differences in home vs. non-home emergency medical services (EMS) scene transports and that among age groups there are differences in demographics.

METHODS

Data were extracted from the EMS State Ambulance Transport database of all reported during 1995. Transports from patient homes were compared with transports from all non-home scenes. Data extracted included age, gender, race, and type of complaint. Subgroup analysis was performed based on age groups in nonvehicular cases, safety problems, and interpersonal violence. Results were compared using a two-tailed chi-square with significance at p<0.05. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for significant differences.

RESULTS

The study included 118,131 transported patients: 13% were children, 49% were adult between 18 and 64 years, and 38% were elder; 13% were African American, 82% were white, and 5% were other; 47% were male and 53% were female. Fifty-eight percent of the transports were for safety problems, and 17% were for interpersonal violence. Of the 118,131 transports, 56,812 (48%) were from patients' homes and 61,319 were not. Compared with EMS transports from non-home scenes, fewer home EMS transports were for injury (p<0.01, OR = 0.18, 95% CI = 0.17-0.19) and more home EMS transports were for illness (p<0.01, OR = 5.64, 95% CI = 5.49-5.79). There was no clinically significant difference in age, race, or gender. For all non-vehicular injury transports, the reason was more likely safety problems than interpersonal violence (58% vs. 17%); however, there was no difference in the percentages of type of call between the home and non-home transports. Home EMS transports were more likely interpersonal violence problems among adult patients less than 65 years old; however, among the old and young, the problems were more likely to be safety-related.

CONCLUSION

Forty-eight percent of all EMS transports are from the home. Only 18% of these EMS home transports are for injury-related problems. In general, EMS injury transports are more likely related to safety than to interpersonal violence. Among the home EMS transports, more than 50% of transports for young and old patients are safety-related. A large proportion of the home EMS transports for adults less than 65 years of age, however, are for interpersonal violence.

Deep hypothermic circulatory arrest: I. Effects of cooling on electroencephalogram and evoked potentials

BACKGROUND

Deep hypothermia is an important cerebral protectant and is critical in procedures requiring circulatory arrest. The purpose of this study was to determine the factors that influence the neurophysiologic changes during cooling before circulatory arrest, in particular the occurrence of electrocerebral silence.

METHODS

In 109 patients undergoing hypothermic circulatory arrest with neurophysiologic monitoring, five electrophysiologic events were selected for detailed study.

RESULTS

The mean nasopharyngeal temperature when periodic complexes appeared in the electroencephalogram after cooling was 29.6 degrees C +/- 3 degrees C, electroencephalogram burst-suppression appeared at 24.4 degrees C +/- 4 degrees C, and electrocerebral silence appeared at 17.8 degrees C +/- 4 degrees C. The N20-P22 complex of the somatosensory evoked response disappeared at 21.4 degrees C +/- 4 degrees C, and the somatosensory evoked response N13 wave disappeared at 17.3 degrees C +/- 4 degrees C. The temperatures of these various events were not significantly affected by any patient-specific or surgical variables, although the time to cool to electrocerebral silence was prolonged by high hemoglobin concentrations, low arterial partial pressure of carbon dioxide, and by slow cooling rates. Only 60% of patients demonstrated electrocerebral silence by either a nasopharyngeal temperature of 18 degrees C or a cooling time of 30 minutes.

CONCLUSIONS

With the high degree of interpatient variability in these neurophysiologic measures, the only absolute predictors of electrocerebral silence were nasopharyngeal temperature below 12.5 degrees C and cooling longer than 50 minutes.

Breast cancer knowledge and preventive behaviors: An urban emergency department-based survey

OBJECTIVE

To assess general knowledge and preventive behaviors regarding breast cancer among women who present to an urban emergency department.

METHODS

During a six-month study period, a convenience sampling of women aged 21 years and older who were in treatment and waiting areas was surveyed. The anonymous written survey asked about demographic variables, knowledge, and preventive behaviors regarding breast cancer. Knowledge was assessed with questions about the recommended frequency of breast self-examination and the recommended age for first mammography. Performance was assessed by questions about breast self-exam and mammography. Subgroup analysis was done by age (above and below 40 years old), race, income (above and below the median), insurance type, history of breast lump, and family history (FH) of breast cancer.

RESULTS

Four hundred women completed surveys. Two hundred twelve (53%) correctly knew the answers to the two knowledge questions. Knowledge was greater in women with private insurance. Knowledge of the frequency of breast self-exam was significantly greater among whites and Native Americans than among African Americans, Asians, or Hispanics. Stated performance of preventive behaviors was 72% (288) for breast self-exam and for mammography. Preventive behaviors were significantly more likely to be performed by higher-income and privately-insured women. Breast self-exam was more likely to be done in older women, those with a history of a breast lump, and those with a FH of breast cancer.

CONCLUSIONS

Women with lower income and without private insurance were less likely to be knowledgeable and practice preventive measures for detecting breast disease.

Effectiveness of forced air warming after pediatric cardiac surgery employing hypothermic circulatory arrest without cardiopulmonary bypass

STUDY OBJECTIVE

To evaluate the effectiveness of forced-air warming compared to radiant warming in pediatric cardiac surgical patients recovering from moderate hypothermia after perfusionless deep hypothermic circulatory arrest.

DESIGN

Prospective unblinded study. SETIING: Teaching hospitals.

PATIENTS

24 pediatric cardiac surgical patients.

INTERVENTION

Noncyanotic patients undergoing repair of atrial or ventricular septal defects were cooled by topical application of ice and rewarmed initially in the operating room by warm saline lavage of the pleural cavities. On arrival at the intensive care unit (ICU), patients were warmed by forced air (n = 13) or radiant heat (n = 11). The time, heart rate, and blood pressure at each 0.5 degrees C increase in rectal temperature were measured until normothermia (36.5 degrees C) to determine the instantaneous rewarming rate.

MEASUREMENTS AND MAIN RESULTS

Baseline characteristics were not different in the two groups. The mean (+/- SD) age was 5.6 +/- 3.4 years, weight was 20 +/- 8 kg, esophageal temperature for circulatory arrest was 25.7 +/- 1.3 degrees C, and duration of circulatory arrest was 25 +/- 11 minutes. The mean core temperature on arrival at the ICU was 29.9 +/- 1.3 degrees C and ranged from 26.1 to 31.5 degrees C. The mean rewarming rate for each 0.5 degrees C was greater (p < 0.05) for forced-air (2.43 +/- 1.14 degrees C/hr) than radiant heat (2.16 +/- 1.02 degrees C/hr). At core temperatures <33 degrees C, the rewarming rate for forced-air was 2.04 +/- 0.84 degrees C/hr and radiant heat was 1.68 +/- 0.84 degrees C/hr (p < 0.05). At core temperatures > or = 33 degrees C, the rewarming rate for forced air was 2.76 +/- 1.20 degrees C/hr and radiant heat was 2.46 +/- 1.08 degrees C/min (p = 0.07). Significant determinants of the rewarming rate in a multivariate regression model were age (p < 0.001), temperature (p < 0.05), time after arrival to the intensive care unit (p < 0.05), pulse pressure (p < 0. 05) and warming device (p < 0.001). The duration of ventilatory support and ICU length of stay was not different in the two groups.

CONCLUSIONS

Both forced-air and radiant heat were effective for rewarming moderately hypothermic pediatric patients. When core temperature was less than 33 degrees C, the instantaneous rewarming rate by forced air was 21% faster than by radiant heat.

The utility of anoscopy and colposcopy in the evaluation of male sexual assault victims

STUDY OBJECTIVE

We sought to compare the use of anoscopy and colposcopy in examinations of male sexual assault victims and to characterize the demographics of male sexual assault victims.

METHODS

This is a case series of 67 male sexual assault victims evaluated over an 8-year period by the Sexual Assault Forensic Examination team. The setting is a university-based emergency department serving as the primary site for examination of sexual assault victims by trained nurse practitioners and physician's assistants. Police and victims' advocates are available at the time of the examination. Anoscopy was done routinely over the entire study period in all patients with any anal penetration or involvement. Colposcopy use started in 1994 to magnify and take pictures. Patients were categorized into 2 groups. Group 1 consisted of subjects receiving only anoscopy, and group 2 consisted of subjects receiving initial colposcopy. Anoscopy in group 1 and colposcopy in group 2 were compared for positive results. A positive result was defined as an additional finding to those obtained by means of gross examination by using the test being evaluated (anoscopy versus colposcopy). Colposcopy and anoscopy were also compared among the subjects receiving both tests. Groups were compared by using a Pearson chi(2) test.

RESULTS

Sixty-seven male sexual assault victims were evaluated between 1991 and 1998. The average age was 26+/-8 years, and the distribution of races was 30% black, 62% white, and 8% Hispanic. Results of gross examination were positive in 42 (63%) subjects. Four patients did not receive either anoscopy or colposcopy. Of the remaining 63, 25 patients had anoscopy only (group 1), and 38 patients had initial colposcopy (group 2). There were no significant differences in age, race, or rate of positive gross examination results between groups. Findings in addition to those obtained by means of gross examination were revealed by means of anoscopy in 8 (32%) of 25 subjects in group 1 and colposcopy in 3 (8%) of 38 subjects in group 2 (P =.03, difference 24%, 95% confidence interval 4% to 44%). In the 36 subjects who had both examinations, the gross examination revealed at least one finding in 22 (61%). The combination of anoscopy and colposcopy yielded positive findings in 17 subjects, including 4 subjects who had no findings on gross examination (increasing the positive rate to 26/36 [72%]).

CONCLUSION

In male sexual assault victims with anal penetration, anoscopy is significantly better for gathering evidence than is colposcopy. The addition of colposcopy and anoscopy increased the rate of cases with positive findings from 61% to 72%. These 2 methods together may be a valuable adjunct in gathering evidence of damage.

Hemodynamic monitoring of the postoperative adult cardiac surgical patient

Surgery on the central blood pump, the heart, is performed either to prevent homeostatic compromise (ie, coronary artery disease potentially causing myocardial infarction and heart failure) or to treat actual homeostatic imbalance (ie, valvular disease causing heart failure). The cardiovascular homeostatic state is what we generally define as hemodynamics. The heart must deliver adequate oxygen and nutrients to all organs at appropriate pressures to allow optimal organ function. We monitor hemodynamic variables to assess the adequacy of a given cardiac repair and to detect any organ dysfunction that may independently coexist or be intimately related with the cardiac disease or its surgical repair. Hemodynamic monitoring initially relied on vital signs and periodic physical examination. The current monitoring capabilities have field expanded to include systemic and pulmonary arterial pressures, central venous pressures, cardiac output, systemic and pulmonary vascular resistance, and systemic and mixed venous oxygen saturation. These variables reflect a synthesis of global cardiac function and the peripheral or pulmonary vascular state. Arterial blood gas analysis further assesses the adequacy of overall oxygen delivery, carbon dioxide removal and acid-base balance. Echocardiography allows a qualitative and quantitative description of both global and regional cardiac function to better define the cardiac components of any hemodynamic state.

Gender differences in state-wide EMS transports

There are gender differences in emergency medical services (EMS) transports and management based on diagnosis. Data were extracted from the EMS State Ambulance Transport database. This database exists because of a legal requirement that all EMS transports generated by 911 calls and all interhospital transports be reported to the State EMS Bureau. All ambulance transports reported to the State EMS Division during 1995 were evaluated. Cases were excluded if they were aborted, admission or discharge transports, outpatient transports, or cases listed as "other" without a diagnosis. Gender-related treatment differences were determined for problems for which EMTs have specific treatment options. These were cardiac arrest, chest pain, allergic reactions, and extremity fractures. Results were compared using a two-tailed Chi squared or Fischer's Exact with significance at P < .05. Odds Ratios (OR) and 95% confidence intervals (CIs) were calculated. There were a total of 164,595 ambulance transports reported to the State EMS Division. Of these 76,074 (46%) were men and 88,521 (54%) were women. Of these, 50,211 were excluded. This left 52,607 injury transport and 61,777 illnesses transport. Men were significantly more likely than women to have injuries related to all-terrain vehicle accidents, motorcycle accidents, RV accidents, burns, gunshot wounds, and stab wounds. Men were significantly more likely than women to have illnesses related to cardiac arrest, dead on arrivals (DOAs), drowning, and smoke inhalation. For cardiac arrest transports, significantly more male patients presented ventricular fibrillation, more males received defibrillation, lidocaine, and bicarbonate, but more women received atropine. Male chest pain patients were more likely to receive oxygen and morphine and less likely to receive nitroglycerin. Male allergic reaction patients were more likely to receive an i.v. and subcutaneous epinephrine. Male extremity fracture patients were more likely to get an i.v. line, but there was no difference in morphine use or splinting. There are numerous disease-specific gender differences in the demographics of illness and injury transported by EMS. The use of various medications and procedures may also be related to gender. Understanding these differences may help in preparing EMS professionals for patient management.

Regulation of elastinolytic cysteine proteinase activity in normal and cathepsin K-deficient human macrophages

Human macrophages mediate the dissolution of elastic lamina by mobilizing tissue-destructive cysteine proteinases. While macrophage-mediated elastin degradation has been linked to the expression of cathepsins L and S, these cells also express cathepsin K, a new member of the cysteine proteinase family whose elastinolytic potential exceeds that of all known elastases. To determine the relative role of cathepsin K in elastinolysis, monocytes were differentiated under conditions in which they recapitulated a gene expression profile similar to that observed at sites of tissue damage in vivo. After a 12-d culture period, monocyte-derived macrophages (MDMs) expressed cathepsin K in tandem with cathepsins L and S. Though cysteine proteinases are acidophilic and normally confined to the lysosomal network, MDMs secreted cathepsin K extracellularly in concert with cathepsins L and S. Simultaneously, MDMs increased the expression of vacuolar-type H(+)-ATPase components, acidified the pericellular milieu, and maintained extracellular cathepsin K in an active form. MDMs from a cathepsin K-deficient individual, however, retained the ability to express, process, and secrete cathepsins L and S, and displayed normal elastin-degrading activity. Thus, matrix-destructive MDMs exteriorize a complex mix of proteolytic cysteine proteinases, but maintain full elastinolytic potential in the absence of cathepsin K by mobilizing cathepsins L and S.

Domestic violence awareness in a medical school class: 2-year follow-up

BACKGROUND

[corrected] Previous studies have examined short-term effectiveness of domestic violence instruction. We studied the long-term effectiveness (LTE) and long-term retention (LTR) of formal instruction about domestic violence.

METHODS

A general knowledge survey on domestic violence was given before, 1 month after, and 2 years after 3 hours of instruction to medical students. Good LTE was defined as significant improvement in responses between the first and third surveys. Good LTR was defined as lack of a significant decrease in results between the second and third surveys.

RESULTS

Two years after the instruction, 104 of 148 (70%) participated. Knowledge of rates of domestic violence against women showed neither good LTE nor good LTR. Responses showed good LTE and LTR concerning domestic violence incidence among men, ethnic and socioeconomic groups being equally represented, victims not being personally responsible for the abuse, and physicians not being required to report domestic violence in the survey state. Responses showed poor LTR and LTE regarding rates of domestic violence in women and abused persons being unable to simply leave their situation.

CONCLUSIONS

Some improvement in domestic violence awareness was seen 2 years after instruction. However, some information was not retained. Domestic violence instruction should be reemphasized throughout medical school.