Activity and dosage of alteplase dilution for clearing occlusions of venous-access devices.

The activity and sterility of reconstituted alteplase solution and the effectiveness of an alteplase dose-escalation protocol for the clearance of midline-catheter and central-venous-access device occlusions were studied. Reconstituted alteplase solution was stored at -70, -25, or 2 degrees C at concentrations of 0.5, 1, or 2 mg/mL. Durations of storage in the freezer were 0, 7, and 14 days, and durations of storage in the refrigerator were 0, 48, and 72 hours and 7 and 14 days. Samples were also assayed and cultured without prior freezing after refrigeration at 2 degrees C for 0, 48, and 72 hours and 7, 14, and 28 days. Fifty-eight pediatric and adult patients were enrolled in a separate study in which catheter clearance was initiated with alteplase 0.5 mg, and the dose was escalated to 1 and 2 mg sequentially until the catheter was cleared. The primary endpoint was restoration of catheter patency, and the secondary endpoint was the occurrence of bleeding episodes within 24 hours of alteplase administration. Catheter removal due to failure to restore patency was also documented. The activity and sterility of alteplase were maintained under all conditions studied. Fifty catheters (86.2%) were cleared with alteplase 0.5 mg, 5 (8.6%) after dose escalation to 1 mg, and 1 (1.7%) after escalation to 2 mg. The alteplase solution did not clear the occlusion in 2 catheters (3.4%): 1 had a mechanical obstruction and 1 cleared two hours after the 1-mg dose was deemed a failure. None of the six catheter removals was due to recalcitrant clots. Bleeding observed was not considered to be the result of alteplase administration. For use in clearing occlusions of venous-access devices, alteplase 0.5, 1, and 2 mg/mL retained sufficient fibrinolytic activity when stored for up to 14 days at 2 degrees C (28 days for the 0.5-mg/mL dilution) and when stored for 14 days at -70 or -25 degrees C followed by up to 14 days at 2 degrees C. The dose-escalation protocol was effective.

Challenges faced in recruiting patients from primary care practices into a physical activity intervention trial. Activity Counseling Trial Research Group.

BACKGROUND: Special challenges are encountered when clinical trial recruitment targets a physician practice-based population, as opposed to recruiting from the community. Since most published information about recruitment has focused on the latter group, summation of successful primary-care-based recruitment strategies could prove useful for future trials recruiting from this population. METHODS: The Activity Counseling Trial (ACT) is a multicenter, randomized clinical trial that evaluated approaches to primary care-based interventions to increase physical activity in sedentary adults 35-75 years of age. Fifty-four clinicians from eight practices recruited 874 participants from three U.S. sites. Recruitment challenges that related, in great part, to the primary care setting included: (1) focusing on patients from ACT physician practices who had regularly scheduled or intend-to-schedule appointments within the next year; (2) placing trial staff in the clinical offices for recruitment purposes; and (3) placing trial interventionists in the physicians' offices. Other challenges were related to recruitment of minorities and men. RESULTS: Patient mailing yielded 43.4% of all randomized participants, followed by office-based questionnaires (32.5%) and direct telephone contact (21.6%). Based on a retrospective cost-effective analysis (indirect costs excluded), the self-administered office-based questionnaire was the least costly strategy for one site ($14/randomized participant), followed by patient mailing at another site ($58). The direct telephone contact method utilized at one site serving primarily a minority population yielded a per randomized participant cost of $80. CONCLUSIONS: Recruitment of clinical trial participants from practice-based populations requires modification of the strategies used to recruit from the community. Multiple strategies should be employed, followed closely for their respective yields, and adapted as needed.

Injuries and deaths due to firearms in the home.

OBJECTIVE: Determine the relative frequency with which guns in the home are used to injure or kill in self-defense, compared with the number of times these weapons are involved in an unintentional injury, suicide attempt, or criminal assault or homicide. METHODS: We reviewed the police, medical examiner, emergency medical service, emergency department, and hospital records of all fatal and nonfatal shootings in three U.S. cities: Memphis, Tennessee; Seattle, Washington; and Galveston, Texas. RESULTS: During the study interval (12 months in Memphis, 18 months in Seattle, and Galveston) 626 shootings occurred in or around a residence. This total included 54 unintentional shootings, 118 attempted or completed suicides, and 438 assaults/homicides. Thirteen shootings were legally justifiable or an act of self-defense, including three that involved law enforcement officers acting in the line of duty. For every time a gun in the home was used in a self-defense or legally justifiable shooting, there were four unintentional shootings, seven criminal assaults or homicides, and 11 attempted or completed suicides. CONCLUSIONS: Guns kept in homes are more likely to be involved in a fatal or nonfatal accidental shooting, criminal assault, or suicide attempt than to be used to injure or kill in self-defense.

Risk factors for violent death of women in the home.

OBJECTIVES: To determine risk factors for violent death of women in the home, and particularly, to assess the strength and direction of any association between domestic violence or keeping firearms and homicide or suicide in the home. METHODS: Subgroup analysis of a large population-based case-control study database was performed, defining cases as all homicides and suicides occurring in the homes of female victims in 3 metropolitan counties: Shelby County, Tennessee; King County, Washington; and Cuyahoga County, Ohio. Randomly selected control subjects were matched to the victims by neighborhood, sex, race, and age range. Exposures to potential risk factors were ascertained by interviewing a proxy for the victim 3 to 6 weeks after the violent death occurred. These answers were compared with those obtained from controls using matched-pairs methods. RESULTS: All cases (n = 266) were identified in the 3-county area, including 143 homicides and 123 suicides, during a 5-year period. Matching controls (n = 266) were also identified. Firearms were involved in 46% of the homicides and 42% of the suicides. Independent risk factors for suicide in the home included a history of mental illness (odds ratio [OR], 258.8; 95% confidence interval [CI], 18.2-3679.8), living alone (OR, 13.4; 95% CI, 2.0-87.8), and having 1 or more guns in the home (OR, 4.6; 95% CI, 1.2-17.5). Independent risk factors for homicide included living alone (OR, 5.1; 95% CI, 2.0-13.2), illicit drug use by any member of the household (OR, 4.9; 95% CI, 1.3-15.9), prior domestic violence (OR, 4.0; 95% CI, 1.5-10.5), 1 or more guns in the home (OR, 3.4; 95% CI, 1.6-7.1), and previous arrest of any member of the household (OR, 3.0; 95% CI, 1.3-6.6). The increased risk of homicide associated with domestic violence, firearms, or illicit drugs was attributable to the homicides at the hands of a spouse, intimate acquaintance, or close relative. CONCLUSIONS: Among women, mental illness and living alone increase the risk of suicide in the home, and household use of illicit drugs and prior domestic violence increase the risk of homicide. Instead of conferring protection, keeping a gun in the home is associated with increased risk of both suicide and homicide of women. Household use of illicit drugs, domestic violence, and readily available firearms place women at particularly high risk of homicide at the hands of a spouse, an intimate acquaintance, or a close relative. Many factors place women at increased risk of violent death in the home. Community- and clinic-based interventions should target those with identifiable risk factors.

Injuries due to firearms in three cities.

BACKGROUND: To describe the incidence and outcome of injuries due to firearms, we conducted a population-based study of fatal and nonfatal gunshot wounds in three cities: Memphis, Tennessee; Seattle; and Galveston, Texas. METHODS: Records of the police, medical examiners, ambulance crews, and hospital emergency departments and hospital admissions were monitored to identify all injuries caused by firearms that were severe enough to prompt emergency medical treatment. These records were linked to generate a complete picture of each event. Census data were used to calculate rates of injury for various population groups. RESULTS: A total of 1915 cases of injury due to firearms were identified between November 16, 1992, and May 15, 1994. The crude rate of firearm injury per 100,000 person-years was 222.6 in Memphis, 143.6 in Galveston, and 54.1 in Seattle. Approximately 88 percent of the injuries were incurred during confirmed or probable assaults; 7 percent were sustained in the course of suicide or attempted suicide; unintentional injuries accounted for 4 percent of the cases. Handguns were used in 88 percent of the cases in which the type of weapon was recorded. Five percent of the 1677 victims who were brought to a hospital emergency department could not be resuscitated; 53 percent were hospitalized, and 42 percent were treated and released. Ninety-seven percent of the deaths occurred within 24 hours of the injury. Emergency department and inpatient charges exceeded $16.5 million. CONCLUSIONS: Injuries due to firearms, most involving handguns, are a major cause of morbidity and mortality in U.S. urban areas. The incidence varies greatly from city to city.

Gun ownership as a risk factor for homicide in the home.

BACKGROUND: It is unknown whether keeping a firearm in the home confers protection against crime or, instead, increases the risk of violent crime in the home. To study risk factors for homicide in the home, we identified homicides occurring in the homes of victims in three metropolitan counties. METHODS: After each homicide, we obtained data from the police or medical examiner and interviewed a proxy for the victim. The proxies' answers were compared with those of control subjects who were matched to the victims according to neighborhood, sex, race, and age range. Crude and adjusted odds ratios were calculated with matched-pairs methods. RESULTS: During the study period, 1860 homicides occurred in the three counties, 444 of them (23.9 percent) in the home of the victim. After excluding 24 cases for various reasons, we interviewed proxy respondents for 93 percent of the victims. Controls were identified for 99 percent of these, yielding 388 matched pairs. As compared with the controls, the victims more often lived alone or rented their residence. Also, case households more commonly contained an illicit-drug user, a person with prior arrests, or someone who had been hit or hurt in a fight in the home. After controlling for these characteristics, we found that keeping a gun in the home was strongly and independently associated with an increased risk of homicide (adjusted odds ratio, 2.7; 95 percent confidence interval, 1.6 to 4.4). Virtually all of this risk involved homicide by a family member or intimate acquaintance. CONCLUSIONS: The use of illicit drugs and a history of physical fights in the home are important risk factors for homicide in the home. Rather than confer protection, guns kept in the home are associated with an increase in the risk of homicide by a family member or intimate acquaintance.

Suicide in the home in relation to gun ownership.

BACKGROUND: It has been suggested that limiting access to firearms could prevent many suicides, but this belief is controversial. To assess the strength of the association between the availability of firearms and suicide, we studied all suicides that took place in the homes of victims in Shelby County, Tennessee, and King County, Washington, over a 32-month period. METHODS: For each suicide victim (case subject), we obtained data from police or the medical examiner and interviewed a proxy. Their answers were compared with those of control subjects from the same neighborhood, matched with the victim according to sex, race, and age range. Crude and adjusted odds ratios were calculated with matched-pairs methods. RESULTS: During the study period, 803 suicides occurred in the two counties, 565 of which (70 percent) took place in the home of the victim. Fifty-eight percent (326) of these suicides were committed with a firearm. After excluding 11 case subjects for various reasons, we were able to interview 80 percent (442) of the proxies for the case subjects. Matching controls were identified for 99 percent of these subjects, producing 438 matched pairs. Univariate analyses revealed that the case subjects were more likely than the controls to have lived alone, taken prescribed psychotropic medication, been arrested, abused drugs or alcohol, or not graduated from high school. After we controlled for these characteristics through conditional logistic regression, the presence of one or more guns in the home was found to be associated with an increased risk of suicide (adjusted odds ratio, 4.8; 95 percent confidence interval, 2.7 to 8.5). CONCLUSIONS: Ready availability of firearms is associated with an increased risk of suicide in the home. Owners of firearms should weigh their reasons for keeping a gun in the home against the possibility that it might someday be used in a suicide.

Chirality, charge, and chain branching effects on dithiocarbamate-induced mobilization of cadmium from intracellular deposits in mice.

The effects of three major structural features on the intracellular cadmium mobilizing potency of dithiocarbamates have been examined. These features, the chirality of the groups, the total ionic charge of the chelating agent, and the extent of chain branching, would be expected to affect the pharmacological properties of these chelating agents but to have little effect on the stability constants of the cadmium complexes involved. A total of 25 compounds (including 21 new ones) was prepared and used in animal studies designed to evaluate these effects. These included a series of amphipathic dithiocarbamates of the general type R1N(R2)CS2-Na+, where R1 is a relatively nonpolar organic group and R2 is derived from a reducing hexose. All of the factors examined influenced the potency of dithiocarbamates in the mobilization of cadmium from intracellular deposits. The compounds with R2 = galactose or mannose and R1 = benzyl were both more effective than the corresponding glucose derivatives in inducing the removal of cadmium from the liver and the whole body. Increases in the net negative charge of the chelating agent uniformly decreased the observed potency in the mobilization of hepatic and renal cadmium deposits. The replacement of a normal alkyl group by a branched-chain group of the same molecular weight also led to an increase in potency for the two pairs of compounds examined. Dithiocarbamates which are not amphipathic because of the presence of similar polar substituents for both R1 and R2, such as sodium diarabitylamine carbodithioate, were relatively ineffective as agents for the mobilization of intracellular cadmium.(ABSTRACT TRUNCATED AT 250 WORDS)

Validating survey responses to questions about gun ownership among owners of registered handguns.

While survey-based data on firearm ownership are essential for epidemiologic studies of the relation between gun ownership and injuries, the validity of respondent answers to questions about gun ownership has not been confirmed. In order to assess the accuracy of interview data about firearms, in June to August 1987, the authors attempted to contact residents of 75 homes in the cities of Memphis, Tennessee and Seattle, Washington listed as the address of the owner of a recently registered handgun. Despite problems with inaccurate registration data, contact was ultimately made with 55 households, 35 of which consented to a general interview that included a series of questions about gun ownership. Respondents in 31 of these 35 households (88.6%) readily acknowledged that one or more guns were kept in their home. Respondents in three of the remaining four households (8.6%) stated that guns were recently kept in their homes but were no longer kept there. Only one respondent (2.9%) denied categorically that guns of any kind were kept in her home. The authors conclude that, at least among registered gun owners, respondent answers to questions about gun ownership are generally valid and that survey data of this type can be utilized with confidence.