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Biomedical subjects

Matthew Miller

Publications and source records attributed to Matthew Miller.

29 records · Page 2Linked to original sources

Regulation of myosin-VI targeting to endocytic compartments.

Myosin-VI has been implicated in endocytic trafficking at both the clathrin-coated and uncoated vesicle stages. The identification of alternative splice forms led to the suggestion that splicing defines the vesicle type to which myosin-VI is recruited. In contrast to this hypothesis, we find that in all cell types examined, myosin-VI is associated with uncoated endocytic vesicles, regardless of splice form. GIPC, a PDZ-domain containing adapter protein, co-assembles with myosin-VI on these vesicles. Myosin-VI is only recruited to clathrin-coated vesicles in cells that express high levels of Dab2, a clathrin-binding adapter protein. Overexpression of Dab2 is sufficient to reroute myosin-VI to clathrin-coated pits in cells where myosin-VI is normally associated with uncoated vesicles. In normal rat kidney (NRK) cells, which express high endogenous levels of Dab2, splicing of the globular tail domain further modulates targeting of ectopically expressed myosin-VI. Although myosin-VI can be recruited to clathrin-coated pits, we find no requirement for myosin-VI motor activity in endocytosis in NRK cells. Instead, our data suggest that myosin-VI recruitment to clathrin-coated pits may be an early step in the recruitment of GIPC to the vesicle surface.

Actins↗

Youth suicide: insights from 5 years of Arizona Child Fatality Review Team data.

Data on 153 youth suicides in Arizona (1994-1999) were used to explore demographic, behavioral, and experiential factors that distinguish between firearm suicide and suicide by other means. In bivariate analyses, White youths were more likely than non-White youths to use a firearm to commit suicide as were youths who had not experienced a life crisis or expressed suicidal thoughts in the past, relationships that hold in multivariate analyses at the p < 0.2 level. Targeted suicide prevention activities should supplement interventions focused on restricting access to highly lethal means of suicide such as firearms.

Adolescent↗

The dilemma of the selfish herd: the search for a realistic movement rule.

The selfish herd hypothesis predicts that aggregations form because individuals move toward one another to minimize their own predation risk. The "dilemma of the selfish herd" is that movement rules that are easy for individuals to follow, fail to produce true aggregations, while rules that produce aggregations require individual behavior so complex that one may doubt most animals can follow them. If natural selection at the individual level is responsible for herding behavior, a solution to the dilemma must exist. Using computer simulations, we examined four different movement rules. Relative predation risk was different for all four movement rules (p<0.05). We defined three criteria for measuring the quality of a movement rule. A good movement rule should (a) be statistically likely to benefit an individual that follows it, (b) be something we can imagine most animals are capable of following, and (c) result in a centrally compact flock. The local crowded horizon rule, which allowed individuals to take the positions of many flock-mates into account, but decreased the influence of flock-mates with distance, best satisfied these criteria. The local crowded horizon rule was very sensitive to the animal's perceptive ability. Therefore, the animal's ability to detect its neighbors is an important factor in the dynamics of group formation.

Animals↗

'Road rage' in Arizona: armed and dangerous.

Little is known about the relationship between firearm carrying and hostile behavior on the roadway. To explore a possible association between firearm carrying by drivers and hostile driving behavior we conducted a random-digit-dial survey of 790 licensed drivers in Arizona. In addition to demographic questions, we asked whether respondents had carried a gun while driving in the 12 months prior to the survey. Respondents were also asked if they, in anger, had personally made obscene gestures, cursed or shouted at other drivers, impeded another drivers progress with their vehicle, aggressively 'followed another driver too closely', or brandished a gun at another driver. We used multivariable logistic regression to explore correlates of hostile driving behavior while taking into account several demographic and behavioral characteristics. Overall 11% of drivers always (4%) or sometimes (7%) carried a gun with them in their vehicle; 34% report having made obscene gestures/cursed/shouted angrily; 28% report aggressively following or blocking other drivers with their vehicle. In both crude and multivariate adjusted analyses, self-report of engaging in hostile behavior while driving was significantly more common among men, young adults, and individuals who carried a firearm in their car. Our findings suggest that, at least among Arizona motorists, having a gun in the car is a strong marker for aggressive and illegal behavior behind the wheel.

Accidents, Traffic↗

Guns and gun threats at college.

A random sample of more than 10,000 undergraduate students, selected from 119 4-year colleges, answered a mailed questionnaire about gun possession and gun threats. Approximately 4.3% of the students reported that they had a working firearm at college, and 1.6% of them have been threatened with a gun while at school. Students are more likely to have a firearm at college and to be threatened with a gun while at college if they are male, live off campus, binge drink, engage in risky and aggressive behavior after drinking, and attend institutions in regions of the United States where household firearm prevalence is high. Having a firearm for protection is also strongly associated with being threatened with a gun while at college. Students who reported having firearms at college disproportionately reported that they engaged in behaviors that put themselves and others at risk for injury.

Adolescent↗

Firearm availability and suicide, homicide, and unintentional firearm deaths among women.

CONTEXT: In the United States, more than 45,000 women died from gun violence over the last decade. OBJECTIVE: To determine whether measures of firearm availability are related to rates of suicide, homicide, and unintentional firearm deaths among women in the United States. DESIGN: Pooled cross-sectional time series data on suicide, homicide, and unintentional firearm deaths (1988-1997) were used to estimate the association between the rate of violent death among women and four proxies of firearm availability. Two proxies came from survey reports of household firearm ownership rates; two were derived from mortality statistics. SETTING: United States, 1988-1997. RESULTS: The increased rate of suicide and homicide in states with high gun levels was accounted for primarily by significantly elevated firearm suicide and firearm homicide rates. Unintentional firearm death rates were also increased in states with more guns. At the regional level, qualitatively similar results were obtained. CONCLUSION: Between 1988 and 1997, the suicide, homicide, and unintentional firearm death rates among women were disproportionately higher in states where guns were more prevalent. The elevated rates of violent death in states with more guns was not entirely explained by a state's poverty or urbanization and was driven primarily by lethal firearm violence, not by lethal nonfirearm violence.

Accidents↗

Household firearm ownership and suicide rates in the United States.

BACKGROUND: In the United States, more people kill themselves with firearms than with all other methods combined. A central question regarding the relation between firearms and suicide is whether the ready availability of firearms increases the suicide rate, rather than merely increasing the proportion of suicides from guns. METHODS: We used publicly available data for the nine regions and 50 states in the United States over a 10-year period (1988-1997) to examine the association between levels of household firearm ownership and rates of suicide, firearm suicide, and non-firearm suicide by age groups and gender. RESULTS: In both regional and state-level analyses, for the U.S. population as a whole, for both males and females, and for virtually every age group, a robust association exists between levels of household firearm ownership and suicide rates. CONCLUSIONS: Where firearm ownership levels are higher, a disproportionately large number of people die from suicide.

Adolescent↗

Rates of household firearm ownership and homicide across US regions and states, 1988-1997.

OBJECTIVES: In this study we explored the association between rates of household firearm ownership and homicide across the United States, by age groups. METHODS: We used cross-sectional time-series data (1988-1997) to estimate the association between rates of household firearm ownership and homicide. RESULTS: In region- and state-level analyses, a robust association between rates of household firearm ownership and homicide was found. Regionally, the association exists for victims aged 5 to 14 years and those 35 years and older. At the state level, the association exists for every age group over age 5, even after controlling for poverty, urbanization, unemployment, alcohol consumption, and nonlethal violent crime. CONCLUSIONS: Although our study cannot determine causation, we found that in areas where household firearm ownership rates were higher, a disproportionately large number of people died from homicide.

Adolescent↗

Firearm availability and female homicide victimization rates among 25 populous high-income countries.

OBJECTIVE: to determine the association between firearm availability and female homicide victimization among high-income countries. METHODS: Data were assembled for the most recent available year (1994-1999) from the official reports of the ministries of health for those countries that had more than 2 million inhabitants and were dassified as high income by the World Bank. Twenty-five nations provided sufficient information for the analysis. Rates of female victimization from homicide, firearm homicide, and nonfirearm homicide were compared with a validated proxy for household firearm ownership (the percentage of total national suicides that are committed with firearms). Possible confounding variables included in the analysis were the percentage of the population living in urban areas and income inequality. RESULTS: The United States is an outlier. It had the highest level of household firearm ownership and the highest female homicide rate. The United States accounted for 32% of the female population in these high-income countries, but for 70% of all female homicides and 84% of all female firearm homicides. Female homicide victimization rates were significantly associated with firearm availability largely because of the United States. CONCLUSION: Among high-income countries, where firearms are more available, more women are homicide victims. Women in the United States are at higher risk of homicide victimization than are women in any other high-income country.

Adult↗

First-pass nuclear angiocardiography in the evaluation of patent ductus arteriosus in dogs.

First-pass nuclear angiocardiography (FPNA) was performed in 5 normal dogs and in 19 dogs with left-to-right shunting patent ductus arteriosus (PDA). Affected dogs were evaluated before and after an occlusion procedure (surgical ligation or transarterial coil embolization). Two methods of analysis were used to evaluate the pulmonary time-activity curves and assess the magnitude of the shunt. One method involved the calculation of a simple count ratio (C2:C1). The other method used gamma variate modeling to estimate the ratio of pulmonary to systemic blood flow (QP:QS). Values for normal dogs (mean +/- SD) were C2:C1 = 0.39 +/- 0.11 and QP:QS = 1.10 +/- 0.03. Values for affected dogs were C2:C1 = 0.59 +/- 0.17, QP:QS = 2.01 +/- 0.46 before intervention and QP:QS = 1.21 +/- 0.17, C2:C1 = 0.42 +/- 0.12 after intervention. Both methods detected significant differences between normal and affected dogs (QP:QS, t-test, P < .001; C2:C1; t-test; P = .018) and between affected dogs pre- and postocclusion (QP:QS. paired t-test, P < .001; C2:C1, paired t-test, P = .002). However, QP:QS was a better separator of normal from affected animals. First-pass nuclear angiocardiography, by the gamma variate method, may be a useful, adjunct diagnostic test in evaluation of animals with left-to-fight shunting PDA, particularly in animals with residual shunting after an occlusion procedure.

Angiocardiography↗