Arterial response to excimer and argon laser irradiation in the atherosclerotic swine

Injury associated with laser-induced tissue ablation may be reduced by using pulsed energy delivery at low repetition rates, as opposed to using continuous wave energy delivery. This study was designed to examine the similarities and differences between these two systems as regards the healing process, and to examine whether one is superior to the other. In order to test this postulate, the healing response of normal and atherosclerotic aorta were examined after exposure in vivo to argon and excimer (XeCl 308 nm) laser radiation in hypercholesterolemic swine. Swine were fed hyperlipidemic diets for eight months following balloon denudation of the descending aorta. Following general anaesthetic, the descending aorta was isolated and laser burns were made on both normal and atherosclerotic intima using a continuous wave argon laser delivered through a 50 diameter quartz fibre, and a XeCl excimer laser carried through a 1 mm diameter fibre. Energy levels of 3 to 5 J were applied with the argon laser. The pulse duration for the excimer laser was 30 ns and craters were produced using 10 to 60 pulses at a repetition rate of 20 Hz and an energy density of 2 J cm^–2.Forty-eight hours after laser application, craters created by both lasers were filled with thrombus material. Argon burns were surrounded by thermal and acoustic injury which was not seen with excimer burns. Three weeks after laser application all crater surfaces were reconstituted. Unlike the excimer burns, argon craters demonstrated necrosis well beyond the crater margins and were characterized by multinucleate giant-cell reaction surrounding char debris. By nine weeks both excimer and argon laser burns were covered by fibrous tissue but could be distinguished by the fact that char debris and subjacent tissue injury arose with the argon burns.The results suggest that both lasers can be used to remove focal atherosclerotic plaque from arteries without inducing excessive thrombogenicity. Rapid healing is observed with both; however, damage to surrounding tissue is significantly greater with a continuous energy delivery laser as opposed to pulsed energy delivery.Work supported in part by: Heart and Stroke Foundation of Ontario, Grant-in-Aid No. 5-17     

Coronary heart disease, chronic inflammation, and pathogenic social hierarchy: a biological limit to possible reductions in morbidity and mortality

We suggest that a particular form of social hierarchy, which we characterize as "pathogenic", can, from the earliest stages of life, exert a formal analog to evolutionary selection pressure, literally writing a permanent developmental image of itself upon immune function as chronic vascular inflammation and its consequences. The staged nature of resulting disease emerges "naturally" as a rough analog to punctuated equilibrium in evolutionary theory, although selection pressure is a passive filter rather than an active agent, like structured psychosocial stress. Exposure differs according to the social constructs of race, class, and ethnicity, accounting in large measure for observed population-level differences in rates of coronary heart disease across industrialized societies. American Apartheid, which enmeshes both majority and minority communities in a social construct of pathogenic hierarchy, appears to present a severe biological limit to continuing declines in coronary heart disease for powerful as well as subordinate subgroups: "Culture"--to use the words of the evolutionary anthropologist Robert Boyd--"is as much a part of human biology as the enamel on our teeth".     

Thiosulfate-citrate-bile salts-sucrose agar and its selectivity for clinical and marine vibrio organisms

Recently documented Vibrio cholerae and non-cholera vibrio infections in Florida and other American waters led to a study to determine the selectivity of thiosulfate-citrate-bile salts-sucrose media (TCBS). Thirty-one species with 188 different strains of clinical, marine, and stock origin were examined on the TCBS media. One hundred seventy-seven of the 188 strains grew. Nine species had the typical yellow colony appearance that might be confused with V. cholerae and nine species were green, potentially confused with V. parahemolyticus or V. vulnificus. Old versus new media were compared with mixed results. Consistent with earlier studies, TCBS grew vibrios well with distinctive morphology. However, its limited selectivity needs be more widely appreciated in clinical laboratories. Its widespread use is advocated to detect the vibrio infections associated with seafood ingestion or wounds exposed to seawater.     

Prostate-specific membrane antigen (PSMA)-mediated laminin proteolysis generates a pro-angiogenic peptide

Prostate-specific membrane antigen (PSMA) is a membrane-bound glutamate carboxypeptidase expressed in a number of tissues. PSMA participates in various biological functions depending on the substrate available in the particular tissue; in the brain, PSMA cleaves the abundant neuropeptide N-acetyl-aspartyl-glutamate to regulate release of key neurotransmitters, while intestinal PSMA cleaves polyglutamated peptides to supply dietary folate. PSMA expression is also progressively upregulated in prostate cancer where it correlates with tumor progression as well as in tumor vasculature, where it regulates angiogenesis. The previous research determined that PSMA cleavage of small peptides generated via matrix metalloprotease-mediated proteolysis of the extracellular matrix protein laminin potently activated endothelial cells, integrin signaling and angiogenesis, although the specific peptide substrates were not identified. Herein, using enzymatic analyses and LC/MS, we unequivocally demonstrate that several laminin-derived peptides containing carboxy-terminal glutamate moieties (LQE, IEE, LNE) are bona fide substrates for PSMA. Subsequently, the peptide products were tested for their effects on angiogenesis in various models. We report that LQ, the dipeptide product of PSMA cleavage of LQE, efficiently activates endothelial cells in vitro and enhances angiogenesis in vivo. Importantly, LQE is not cleaved by an inactive PSMA enzyme containing an active site mutation (E424S). Endothelial cell activation by LQ was dependent on integrin beta-1-induced activation of focal adhesion kinase. These results characterize a novel PSMA substrate, provide a functional rationale for the upregulation of PSMA in cancer cells and tumor vasculature and suggest that inhibition of PSMA could lead to the development of new angiogenic therapies.     

A comparison of the epidemiology of ice hockey injuries between male and female youth in Canada

BACKGROUND:

Hockey is played by youth across Canada, and its popularity has increased dramatically among females in the past decade. Despite this, there has been little epidemiological research comparing the injury patterns of young female and male hockey players.

OBJECTIVE:

To describe and compare injuries sustained by female and male youth hockey players using the Canadian Hospitals Injury Reporting and Prevention Program database.

METHODS:

In the present cross-sectional, retrospective comparison study, the Canadian Hospitals Injury Reporting and Prevention Program database was used to identify all hockey-related injuries sustained by children seven to 17.5 years of age over a 15-year period (January 1995 to December 2009). Exclusion criteria included paid professional players and children with injuries sustained while playing road hockey.

RESULTS:

Inclusion criteria were met by 33,233 children (2637 [7.9%] females and 30,596 [92.1%] males). Compared with males, females reported proportionately more soft tissue injuries (39.8% versus 32.6%; P<0.01) and sprains/strains (21.1% versus 17.6%; P<0.01). Males experienced more fractures (27.1% versus 18.2%; P<0.01) and were most often injured through body checking (42.8% versus 25.7%; P<0.01). Females showed a trend toward increased concussion with age, and were most often injured through collisions (28.6% versus 24.6%; P<0.01).

CONCLUSION:

Compared with males, female hockey players sustained proportionately more soft tissue injures and sprains/strains, and showed a trend toward concussions in late adolecence. Males experienced more fractures, shoulder injuries and injuries due to body checking. Further research is required to identify risk factors for injury in female youth hockey players and to target injury prevention.     

Intersectionality as an Analytic Framework for Understanding the Experiences of Mental Health Stigma Among Racialized Men

International Journal of Mental Health and Addiction - The objective of this research was to use intersectionality to explore Asian men’s experiences of stigma and mental illness to tease out...     

The Mongolian gerbil in aging research

The authors have explored the suitability of the Mongolian gerbil as a model in aging research and reviewed data on major factors in gerbil morbidity and mortality. The gerbil is a semi-desert rodent, introduced relatively recently into biomedical research. It is moderately prolific, has a maximum survival of about 208 weeks and is easily maintained. Maternal neglect, fighting and epidemic diseases (Tyzzer's disease, salmonellosis, pneumonia) are potential causes of mortality in gerbil colonies. Obese or breeding gerbils may exhibit hyperadrenocorticism, diabetes, non-lipoid arteriosclerosis and secondary lesions in several organs. There is a high prevalence of spontaneous neoplasms in aged gerbils, especially tumors of the adrenal cortex, ovary and skin. The gerbil is a useful model of experimentally-induced stroke, but has proven unsuitable for studies of cholesterol-induced atherosclerosis. The normal and pathological anatomy of periodontal disease in the gerbil is similar in many respects to that of man.     

Laparoscopic ventral incisional hernia repair: A more effective alternative to conventional repair of recurrent incisional hernia

Conventional repair of recurrent ventral incisional hernia is associated with a higher recurrence rate (30%-50%) than repair of primary incisional hernia (11%-20%). Laparoscopic incisional hernia repair (LIHR) can significantly reduce the recurrence rate of primary hernia to less than 5%. In this study, we evaluate the efficacy of repairing recurrent incisional hernia laparoscopically. One-hundred and seventy consecutive patients undergoing LIHR between January 1995 and December 2002 were prospectively reviewed. Patients with recurrent incisional hernia (n = 69) were compared to patients with primary incisional hernia (n = 101). Patient demographics and perioperative and postoperative data were recorded prospectively. Follow-up was obtained from office visits and telephone interviews. Statistical analysis was performed using the Student t test and the x ²test. Results are expressed as means ± standard deviation. The patients with recurrent incisional hernia had a mean of 1.9 ± 1.3 previous repairs, higher body mass index (BMI) (34 ± 6 kg/m² vs. 33 ± 8 kg/m², P = 0.46), larger defect size (123 ± 115 cm² vs. 101 ± 108 cm², P = 0.06), and longer operative time (119 ± 61 minutes vs. 109 ± 44 minutes, P= 0.11). The complication rate was higher in the recurrent group (28% vs. 11%, P = 0.01), but the recurrence rate was not different (7% vs. 5%, P= 0.53). The mean time to recurrence was significantly shorter in the recurrent group (3 ± 2 months vs. 14 ± 7 months, P < 0.0001). The mean follow-up interval was 19 ± 18 months in the recurrent group and 27 ± 20 months in the primary group. Although laparoscopic repair of recurrent incisional hernia resulted in a higher recurrence and complication rate than laparoscopic repair of primary incisional hernia, the rates were lower than those reported for conventional repair of recurrent incisional hernia. Laparoscopic repair of recurrent incisional hernia is an effective alternative to conventional repair. Supported in part by Tyco/US Surgical Corporation through an educational grant to the University of Kentucky Center for Minimally Invasive Surgery.