Multiple vertebral compression fractures in a human immunodeficiency virus-positive patient with glucocorticoid-induced Cushing syndrome treated with percutaneous vertebroplasty: a case report.

The authors present a rare case of multiple vertebral compression fractures in a young female with iatrogenic glucocorticoid-induced Cushing syndrome and concomitant human immunodeficiency virus (HIV) infection. Both long-term steroid use and HIV infection may lead to osteopenia or even osteoporosis. Multiple vertebral fractures in young patients are very uncommon and should alert the examiner to investigate any underlying cause. Treatment choices include pharmacological agents such as bisphosphonates or parathyroid hormone and even surgical interventions such as percutaneous vertebroplasty.

The feasibility and efficacy of laparoscopic repair for chronic traumatic diaphragmatic herniation: introduction of a novel technique with literature review.

PURPOSE: Traumatic diaphragm rupture is a rare trauma that is easily overlooked. A missed diagnosis would result in chronic traumatic diaphragmatic herniation (CTDH). Surgical repair is the standard treatment that is conventionally performed by laparotomy or thoracotomy. Laparoscopic repair has been reported, but its efficacy remains controversial. In this study, we present our novel technique and experience of laparoscopic repair of CTDH and analyze the feasibility and effectiveness of this procedure. METHODS: We conducted a prospective collection with retrospective review of patients with CTDH treated at Chang Gung Memorial Hospital, Taiwan, from 2000 to 2013. The demographic characteristics, surgical procedure, perioperative results, length of hospital stay (HLOS) and follow-up were record and analyzed. RESULTS: There were 114 patients with traumatic diaphragm hernia, and 24 of them had CTDH with a mean age of 54.9 ± 13.3 years. The HLOS was 15.08 ± 8.17 days. Regarding the surgical method used, 19 patients had open surgery, and 5 patients underwent laparoscopic surgery. The demographic distribution, trauma mechanism, location and size of CTDH were comparable. In the laparoscopic group, the patients had a shorter median HLOS (6 days) than in the open surgery group (16 days; p = 0.002). There was no mortality or recurrence in both groups. CONCLUSIONS: In this study and literature review, patients had laparoscopic repair with a smooth recovery. Laparoscopy provides good surgical exposure, allowing easy repositioning of the herniated content and a smooth repair of the defect without the morbidity of laparotomy. For CTDH, with caution, we can apply this technique with an acceptable result.

Predictive factors for early failure of transarterial embolization in blunt hepatic injury patients.

AIM: To evaluate the early success of transarterial embolization (TAE) in patients with traumatic liver haemorrhage and to determine independent factors for its failure. MATERIALS AND METHODS: From January 2009 to December 2012, TAE was performed in 48 patients for traumatic liver haemorrhage. Their medical charts were reviewed for demographic information, pre-TAE vital signs and laboratory data, injury grade, type of contrast medium extravasation (CME) at CT, angiography findings, and early failure. "Early failure" was defined as the need for repeated TAE or a laparotomy for hepatic haemorrhage within 4 days after TAE. Variables were compared between the early success and early failure groups. Variables with univariate significance were also analysed using multivariate logistic regression for predictors of early failure. RESULTS: Among 48 liver TAE cases, nine (18.8%) were early failures due to liver haemorrhage. Early failure was associated with injury grade (p = 0.039), major liver injury (grades 4 and 5; p = 0.007), multiple CMEs at angiography (p = 0.031), incomplete TAE (p = 0.002), and elevated heart rate (p = 0.026). Incomplete embolization (OR = 8; p = 0.042), and heart rate >110 beats/min (bpm; OR = 8; p = 0.05) were independent factors for early failure of TAE in the group with major liver injuries. CONCLUSION: Major hepatic injury is an important factor in early failure. Patients with a heart rate >110 bpm and incomplete embolization in the major injury group have an increased rate of early failure. The success rate of proximal TAE was comparable to that of the more time-consuming, superselective, distal TAE.

Risk factors for liver abscess formation in patients with blunt hepatic injury after non-operative management.

PURPOSE: To identify risk factors for liver abscess formation in patients with blunt hepatic injury who underwent non-operative management (NOM). METHODS: From January 2004 to October 2008, retrospective data were collected from a single level I trauma center. Clinical data, hospital course, and outcome were all extracted from patient medical records for further analysis. RESULTS: A total of 358 patients were enrolled for analysis. There were 13 patients with liver abscess after blunt hepatic injury. Patients with abscess had a significant increase in glutamic oxaloacetic transaminase (GOT, p = 0.006) and glutamic pyruvic transaminase (GPT, p < 0.0001), and a decrease in arterial blood pH (p = 0.023) compared to patients without abscess in the univariate analyses. In addition, high-grade hepatic injury and transarterial embolization (TAE, p < 0.001) were also risk factors for liver abscess formation. Five factors (GOT, GPT, pH level in the arterial blood sample, TAE, and high-grade hepatic injury) were included in the multivariate analysis. TAE, high-grade hepatic injury, and GPT level were statistically significant. The odds ratios of TAE and high-grade hepatic injury were 15.41 and 16.08, respectively. A receiver operating characteristic (ROC) analysis was used for GPT, and it suggested cutoff values of 372.5 U/L. A prediction model based on the ROC analysis had 100 % sensitivity and 86.7 % specificity to predict liver abscess formation in patients with two of the three independent risk factors. CONCLUSIONS: TAE, high-grade hepatic injury, and a high GPT level are independent risk factors for liver abscess formation.

Suppressed gene expression of adipocyte resistin in an insulin-resistant rat model probably by elevated free fatty acids.

Resistin, the peptide specifically secreted from adipocytes, is a hormone antagonistic to insulin action and, thus, may serve as a link between human obesity due to adiposity and insulin resistance associated with type 2 diabetes. To test this hypothesis, we studied the gene expression of resistin in adipocytes isolated from rats fed with a fructose diet which induced insulin resistance. Compared to the control rats (C) on a normal chow diet, the fructose-fed rats (F) developed hyperinsulinemia, glucose intolerance, hypertriglyceridemia and hypertension, a profile reminiscent of the syndrome X of patients with non-insulin-dependent diabetes mellitus (NIDDM). The F rats had significantly elevated plasma free fatty acids (FFA), enlarged epididymal fat pads, and increased adipocyte size compared with the C rats. We examined the glucose transport and the relative quantity of resistin mRNA produced in the adipocytes of these two groups of rats. Compared to the C rats, the F rats had a clearly reduced insulin-stimulated glucose transport. The gene expression of resistin and other adipocyte peptides was measured on the mRNA by semiquantitative RT-PCR; the validity of this technique was established in advance with a rat-fasting and then refeeding experiment. The F rats showed a decreased expression of the resistin gene, whereas gene expression of leptin and angiotensinogen in contrast increased. Free fatty acids were found to suppress the expression of resistin gene in normal rat adipocytes. These results demonstrate that an insulin-resistant instance in the fructose diet rat model exists with the decreased gene expression of resistin.

Understanding work-related upper extremity disorders: clinical findings in 485 computer users, musicians, and others.

Four hundred eighty five patients whose chief complaints were work related pain and other symptoms received a comprehensive upper-body clinical evaluation to determine the extent of their illness. The group had a mean age of 38.5 years. Sixty-three percent of patients were females. Seventy percent were computer users, 28% were musicians, and 2% were others engaged in repetitive work. The time between the onset of symptoms and our initial visit ranged from 2 weeks to over 17 years. A majority sought care within 30 months with the greatest number of them seeking care before 12 months. Fifty nine percent of subjects were still working when seen despite increasing pain and symptoms such as weakness, numbness, tingling, and stiffness. Following a history, a physical assessment utilizing commonly employed clinical tests were performed including evaluation of joint range of motion, hyperlaxity, muscle tenderness, pain, strength, and imbalance. Neurologic tests included Tinel's sign performed in wrist, elbow, tricipital sulcus, and neck and tests for thoracic out syndrome (TOS). Specific tests such as Finkelstein's test for deQuervain's tenosynovitis, Phalen's test for carpal tunnel syndrome and grip strengths were included in the examination protocol. Significant findings included postural misalignment with protracted shoulders (78%), head forward position (71%), neurogenic TOS (70%), cervical radiculopathy (0.03%), evidence of sympathetic dysfunction (20%), and complex regional pain syndrome (RSD) (0.6%). Hyperlaxity of fingers and elbows was found in over 50%, carpal tunnel syndrome in 8%, radial tunnel syndrome in 7%, cubital tunnel in 64%, shoulder impingement in 13%, medial epicondylitis in 60%, lateral epicondylitis in 33%, and peripheral muscle weakness in 70%. We conclude that despite initial presentation distally, work-related upper-extremity disorders are a diffuse neuromuscular illness with significant proximal upper-body findings that affect distal function. While neurogenic TOS remains a controversial diagnosis, the substantial number of patients with positive clinical findings in this study lends weight to the concept that posture related neurogenic TOS is a key factor in the cascading series of physical events that characterize this illness. A comprehensive upper-body examination produces findings that cannot be obtained through laboratory tests and surveys alone and lays the ground work for generating hypotheses about the etiology of work related upper-extremity disorders that can be tested in controlled investigations.

The stimulatory effect of vasoactive intestinal peptides on the cortisol production of guinea pig Zona fasciculata cells: an extra-ACTH regulatory model of the adrenocortical function.

The effect of vasoactive intestinal peptide (VIP) on cortisol production was studied in a primary culture enriched with guinea pig Zona Fasciculata (ZF) cells. In ZF cells, VIP stimulates cortisol secretion and enhances the steroidogenic action of ACTH. Compared to ACTH on an equal molar basis, the cortisol-stimulatory effect of VIP is at least 10-fold less potent. As VIP exhibits a wide range of biological actions with widespread distribution in the body, the steroidogenic action of VIP on the adrenal glands is not tissue-specific. There are VIP receptors in ZF cells. With the aid of a VIP receptor antagonist, we found that ACTH and VIP mutually bind each other's receptors with an affinity-ranking order of ACTH > VIP receptor antagonist > VIP. VIP stimulates cortisol production most likely through the cyclic AMP (cAMP) signaling pathway. Both ACTH receptors and the VIP receptors bind VIP receptor antagonist more avidly than VIP, but the bindings do not lead to a consequential effect on cAMP production and cortisol secretion. However, the VIP receptor antagonist counteracted ACTH and VIP to lower both cAMP and cortisol production. In addition, ASIF and BNP-32, which are the proven ACTH receptor antagonists, reduced the cortisol-stimulatory effect of ACTH and VIP. These results suggest that besides ACTH, VIP be an important factor in regulating the cortisol secretion from the adrenal cortex at the site of ACTH receptors. In cases with hypercortisolemia being detected concomitantly with normal or low ACTH levels, we may need to investigate the influential role of VIP.

Extraction of human DNA for PCR from chewed residues of betel quid using a novel "PVP/CTAB" method.

Residues of chewed betel quid (BQ) are often found on crime scenes in Taiwan and possibly some of the Southeast Asian countries. Although these residues are important biological evidences relating to the suspects, the forensic analysis of BQ evidence has been hindered by failures in extraction of human DNA for PCR analysis. Therefore, it is a prerequisite for relevant forensic casework to establish a reliable method for extracting DNA from chewed BQ residues. Three conventional methods (salt/chloroform, 5% Chelex-100 resin, and QIAamp) were first tested for extraction of human DNA from 33 mock BQ samples, which had been stored for less than two months, and 50 four-year-old forensic BQ samples. PCR amplifications from the HLA-DQA1&PM and the STR loci were then used to test the quality of the extracted DNA. For the mock samples, three observations were made. First, PCR amplification of DNA extracted by using these conventional methods had low success rate. Second, the addition of extra Taq DNA polymerase could compensate the lost enzyme activities due to putative inhibitors and, thus, increase the yield. Third, using the Centricon-100 column to remove putative inhibitors substantially improved the efficiency of PCR. However, for the four-year-old forensic BQ samples, none of the attempts for PCR were successful. In order to solve the problem in PCR analysis of DNA from old BQ samples, we developed a DNA extraction method based on the use of polyvinyl pyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), which bind to two common classes of PCR inhibitors in plants, polyphenols, and polysaccharides, respectively. The result showed that this "PVP/CTAB" method is completely successful for the mock BQ samples, and 92% (46 out of 50) successful for the four-year-old forensic BQ samples. To our best knowledge, this is the first report of a reliable method for the extraction of human DNA for PCR from chewed BQ residues. This method should provide a useful means for forensic identification in countries where betel chewing is common.

Acute appendicitis during pregnancy: a clinical assessment.

BACKGROUND: Acute appendicitis is the most common non-obstetric reason for laparotomy during pregnancy. The purpose of this study was to analyze the characteristics of the clinical presentations and postoperative outcomes of these patients and their fetuses. METHODS: Patients who underwent appendectomies during pregnancy from July 1991 to June 1997 were retrospectively identified. Their ages, clinical presentations, the severity of the inflammatory change in the appendices, and the postoperative complications of these patients and fetuses were recorded and analyzed. Long-term outcomes were confirmed by telephone contact, when possible. RESULTS: Forty-five pregnant women who underwent appendectomies for suspected acute appendicitis were retrospectively reviewed. The histopathological inflammatory change in the appendix was proven in 35 patients (78%). Sixty-three percent of the patients were multiparous, and 86% were in the first 2 trimesters. In the clinical settings, pain and tenderness in the right lower abdominal quadrant were the most common symptoms and signs in presentation. Perioperative administration of ritodrine had no obvious advantage in the prevention of fetal loss. Appendectomy was performed beyond 36 hours of onset of symptoms in 28% of the patients, among whom one-half had gangrenous or perforated appendices. Only one fetus was spontaneously lost in 32 patients with diseased appendices (3%), excluding 3 patients choosing artificial abortion. There was no maternal death in our series. CONCLUSION: The rate of fetal loss due to surgery for acute appendicitis during pregnancy was low. Delay of operation was pertinent to the more-inflammatory changes of the appendix and to the higher maternal complication rate. Early surgical intervention is essential.

Gallbladder torsion: case report and review of the literature.

Torsion of the gallbladder is a surgical emergency, occurring mainly in the elderly. Female is predominant to male with ratio 3 to 1. Despite its unknown etiology, the anatomical variations in the attachment of gallbladder which occur on the mobile mesentery to the inferior margin of the liver are usually found. When the gallbladder twists around the cystic duct and artery, torsion takes place with ensuing occlusion of the flow of bile and blood. Preoperative diagnosis is difficult to make; however, patients who receive prompt surgical treatment with cholecystectomy always get excellent outcomes. Mortality rate is low with 3% to 5%. Here, we report on elderly male patient with gallbladder torsion at our hospital and review the existing literature.

Genetic polymorphisms of the promoter region of dopamine D2 receptor and dopamine transporter genes and alcoholism among four aboriginal groups and Han Chinese in Taiwan.

This study aims to examine the relationship between the functional polymorphism at the promoter region of the dopamine D2 receptor (DRD2) gene (i.e. -141C Ins/Del) and variable number of tandem repeat polymorphism at the 3' untranslated region of the dopamine transporter (DAT) gene (SLC6A3) with alcoholism in a case-control study. The cases (n = 203) were alcohol dependents with withdrawal symptoms, and the controls (n = 213) were sex- and ethnicity-matched individuals who were screened to exclude those with alcohol problems among four aboriginal groups (Atayal, Ami, Bunun, and Paiwan) and Han Chinese in Taiwan. To control for potential confounding factors, we excluded tobacco abusers from control subjects in part of the analysis and compared the distribution of the genetic polymorphisms in alcoholics with severe medical complications versus those with less severe medical complications. There were no differences in allele and genotype frequencies of these two distinct genetic markers between alcoholics and control subjects in these five different ethnic groups. There was no significant linkage disequilibrium between the -141C polymorphism and two other DRD2 polymorphisms (TaqI A and NcoI). The results remained unchanged when cases were limited to alcoholics with more severe medical complications or when tobacco abusers were excluded from control subjects. The results suggest that both the DRD2 promoter region and the DAT gene do not play a significant role in conferring vulnerability to alcoholism.

Simultaneous HPLC of twelve monoamines and metabolites shows neuroblastoma cell line releases HVA and HIAA.

Neuroblastoma is a solid tumor occurring usually in children less than 5 years old. It has been difficult to distinguish neuroblastoma from other childhood tumors through morphological diagnosis. Urine homovanillic acid (HVA), which is a metabolite of dopamine, has been proposed as a diagnostic index. Although increased levels of a serotonin metabolite, 5-hydroxyindole-3-acetic acid (HIAA), have also been observed in urine samples of the patients, they were largely attributed to dietary amines. By using an HPLC system with electrochemical detection, which can simultaneously assay 12 monoamines and metabolites, we showed that HVA and HIAA are two of the most prominent monoamine metabolites in the medium after a neuroblastoma cell line (IMR-32) was cultured for 3 days. Moreover, we found that the levels of HVA and HIAA in the media are proportional to the cell densities. These results suggest that the levels of HVA and HIAA in tissue culture media, or in urine from patients whose dietary amines are well controlled, may provide a valuable diagnostic index for neuroblastoma.

Factors determining operative mortality of grade V blunt hepatic trauma.

BACKGROUND: Despite recent advances in the management of severe hepatic injuries, the operative mortality rate of grade V hepatic injuries still ranges from 67% to 80%. Grade V hepatic injuries involving the retrohepatic cava or main hepatic veins are almost always lethal, especially those from blunt trauma. The purpose of this study is to understand the risk factors determining operative mortality in grade V blunt hepatic trauma, and to try to improve the surgical management of these injuries. METHODS: A retrospective study was conducted at a medical center that offers services including primary, secondary, and tertiary care. Forty-four patients with grade V blunt hepatic injuries were treated during a 6-year period from January 1, 1991, to December 31, 1996. The operative mortality was compared by a multivariate analysis. RESULTS: Forty-four patients with grade V blunt hepatic injuries were identified. Seven patients had only parenchymal injuries, and the others had vascular and associated parenchymal injuries. Venorrhaphy was used in 37 patients; 29 were treated using a nonshunting approach, and 8 with an atriocaval shunt. The overall mortality rate was 68% (30 of 44), and liver-related mortality was 50% (22 of 44). Univariate analysis revealed that the significant variables affecting operative mortality were initial systolic blood pressure, initial base deficit, the Glasgow Coma Scale, injury type, number of resected segments, and total intraoperative blood loss. Based on forward stepping logistic regression analysis, patients with an initial base deficit of -6 mmol/L or less (relative risk = 17.3), and a total intraoperative blood loss of 5,000 mL or more (relative risk = 23.5) would, significantly, encounter a worsening prognosis. CONCLUSIONS: Initial base deficit and total intraoperative blood loss were the significant factors that determined operative mortality after grade V blunt hepatic trauma. We suggest that prompt resuscitation and expeditious and appropriate surgical management, to control operative blood loss, is the only way to reduce operative mortality in patients with grade V blunt hepatic trauma.

Cytokine dysregulation in activated cystic fibrosis (CF) peripheral lymphocytes.

Recent studies demonstrate in vivo and in vitro cytokine dysregulation in CF epithelial cells. To see if these abnormalities may be generalized to other cells expressing cystic fibrosis transmembrane conductance regulator (CFTR) but not directly exposed to local inflammation, we studied mRNA transcription, intracellular protein production and extracellular secretion of IL-2, IL-4, IL-5, IL-10 and interferon-gamma (IFN-gamma) from freshly isolated blood mononuclear and CD4+ T cells from CF patients and controls. Cells were activated by phorbol myristate acetate (PMA) and anti-CD3, PMA-ionomycin, or lipopolysaccharide (LPS) and assessed for cytokine mRNA transcription by semiquantitative reverse transcriptase-polymerase chain reaction, intracellular protein production by flow cytometry, and secretion by supernatant ELISA. Cytokine expression was highly stimulus-dependent. CF cells showed higher IL-10 transcription than control cells after maximal activation by LPS (P = 0.01); despite this, cytokine production and secretion were equivalent to controls. CF cells showed lower cellular IL-10 production after PMA-anti-CD3 activation (P = 0.002). CF cells secreted less IFN-gamma than control cells after maximal activation by PMA-anti-CD3 (1836 +/- 273 pg/ml versus 9635 +/- 3437 pg/ml, P = 0.04). IL-2, IL-4 and IL-5 regulation was similar to controls. We conclude that CF mononuclear cells show selective cytokine dysregulation after maximal activation, namely reduced IFN-gamma secretion and increased IL-10 mRNA without increased production or secretion. These findings extend defects described in respiratory epithelial cells to circulating immunoregulatory cells, suggesting a link between CF genotype and cytokine dysregulation.

Anti-arthropod saliva antibodies among residents of a community at high risk for Lyme disease in California.

The role of the western black-legged tick (Ixodes pacificus) versus that of other potential arthropod vectors in the epidemiology of Lyme disease was evaluated by determining the prevalence of anti-arthropod saliva antibodies (AASA) among residents (n = 104) of a community at high-risk (CHR). Salivary gland extracts prepared from I. pacificus, the Pacific Coast tick (Dermacentor occidentalis), the western cone-nose bug (Triatoma protracta), and the western tree-hole mosquito (Aedes sierrensis) were used as antigens in an ELISA. Sera from 50 residents of the San Francisco Bay region in northern California and 51 residents of Imperial County in southern California served as comparison groups. The prevalence of AASA ranged from 2% for A. sierrensis to 79% for I. pacificus in study subjects, 0% for D. occidentalis to 36% for I. pacificus among residents of the San Francisco Bay region, and 6% for I. pacificus to 24% for A. sierrensis in residents of Imperial County. The associations between AASA and demographic factors, potential risk factors, probable Lyme disease, and seropositivity for Borrelia burgdorferi were assessed for 85 members of the CHR. Seropositivity for I. pacificus and B. burgdorferi were significantly correlated, the relative risk of seropositivity to B. burgdorferi was about 5 (31% versus 6%) for subjects who were seroreactive to I. pacificus, nearly every individual who was seropositive for B. burgdorferi had elevated levels of antibodies to I. pacificus, and the mean titer for antibodies to I. pacificus was significantly higher for subjects seropositive versus those seronegative for B. burgdorferi. Together, these findings support the widely held belief that I. pacificus is the primary vector of B. burgdorferi for humans in northern California, and they demonstrate the utility of the AASA method as an epidemiologic tool for studying emerging tick-borne infections.

Screen for MAOA mutations in target human groups.

Brunner et al. [1993: Am J Hum Genet 52: 1032-1039; 1993: Science 262:578-580] described males with an MAO-A deficiency state resulting from a premature stop codon in the coding region of the MAOA gene. This deficiency state was associated with abnormal levels of amines and amine metabolites in urine and plasma of affected males, as well as low normal intelligence and apparent difficulty in impulse control, including inappropriate sexual behavior. In the present study, disruption of the MAOA gene was evaluated in males with mental retardation with and without a history of sexually deviant behavior, as well as normal controls, healthy males, and patients with other diseases (Parkinson disease, Lesch-Nyhan syndrome). When available, plasma samples were evaluated first for levels of 3-methoxy, 4-hydroxyphenolglycol (MHPG), a metabolite of norepinephrine which serves as the most sensitive index of MAO-A activity in humans. Blood DNA from individuals with abnormally low MHPG, and from other individuals for whom metabolite levels were not available, were screened for nucleotide variations in the coding region of the MAOA gene by single-strand conformational polymorphism (SSCP) analysis across all 15 exons and splice junctions, and by sequencing, when indicated by either altered metabolites or SSCP shifts. No evidence for mutations disrupting the MAOA gene was found in 398 samples from the target populations, including institutionalized mentally retarded males (N = 352) and males participating in a sexual disorders clinic (N = 46), as well as control groups (N = 75). These studies indicate that MAOA deficiency states are not common in humans.

Three studies testing the effects of role models on product users' safety behavior.

Three studies were conducted to determine the effect of a role model's safety behavior on observers' safety behavior. In Studies 1 and 2, role models (confederates) used a cleaning product requiring them to wear safety gloves. Study 1 examined observers' safety behavior after they witnessed a friendly (unfriendly) role model's safety behavior in one of four conditions: 1) wearing rubber gloves, 2) not wearing rubber gloves and experiencing no chemical burn, 3) not wearing rubber gloves and experiencing a mild chemical burn, and 4) not wearing rubber gloves and experiencing a severe chemical burn. In Study 2, participants tested a cleaning product with a warning message (low hazard vs. high hazard) after observing a role model first test the cleaning product in one of the four conditions specified above. As predicted, in Studies 1 and 2, observers were influenced by the role model's safety behavior. However, the friendliness of the role model (Study 1) and level of hazard (Study 2) communicated in the warning message did not influence participants' safety behavior. Using an over-the-counter pain reliever, Study 3 tested the joint effects of: 1) the level of hazard communicated in the warning, 2) observers' outcome-relevant involvement, and 3) role model's compliance. Although the level of hazard communicated in the warning exerted no impact on observers' safety compliance, the role model's safety behavior and level of involvement jointly influenced observers' safety behavior. The implications of the findings and future research directions are discussed. Actual or potential applications of the research include, but are not limited to, using role models in warning messages and safety training programs to demonstrate the proper use of safety gear so as to enhance product users' compliance with safety recommendations.