Biomedical subjects

L Cobb

Publications and source records attributed to L Cobb.

At least 19 recordsLinked to original sources

PubMed2005

Carcinogenicity of radon/radon decay product inhalation in rats--effect of dose, dose rate and unattached fraction.

PURPOSE: The effects of inhalation of radon/radon decay products at different total doses, dose rates and 'unattached' fractions were investigated in a life span study in rats. MATERIALS AND METHODS: 1574 rats inhaled radon/radon decay products in a purpose-built recirculating exposure system that provided stable/reproducible exposure conditions. 501 were maintained as controls. RESULTS: Lung tumour incidences were significantly elevated in most exposed groups. The study power was insufficient to resolve the shape of the dose and dose rate response curves, but combination of this data with that from other studies demonstrated that for high cumulative exposures, the lifetime excess absolute risk increases with increasing exposure durations and for low cumulative exposures the opposite trend occurs. Exposure did not increase leukaemia incidences. A small number of non-lung tumour types including mammary fibroadenoma showed elevated incidences in some exposed groups, however not consistently across all exposure groups and showed no dose or dose rate relationship. CONCLUSIONS: Radon/radon decay product exposure caused excess lung tumours in rats along with limited non-lung effects. The results are consistent with the findings that at low cumulative exposures decreasing exposure concentrations or protracting the time over which the dose is delivered, reduces lung tumour risk. At higher levels, decreasing exposure concentrations or protracting exposure time increases lung tumour risk.

Administration, Inhalation↗

PubMed2001

Cardiac arrest in medical and dental practices: implications for automated external defibrillators.

BACKGROUND: To determine the need for placing automated external defibrillators (AEDs) in medical and dental practices, we identified cardiac arrests at these locations. METHODS: Locations of cardiac arrest were abstracted from Emergency Medical Services data from January 1, 1990, through December 31, 1996. We calculated the annual incidence of cardiac arrest per type of practice. RESULTS: There were 142 cardiac arrests in medical or dental practices. Dialysis centers had a relatively high incidence of cardiac arrest (>/=0.746 per practice annually). Cardiology, internal and family medicine, and urgent care centers had a medium incidence (>/=0.01 per practice annually). All other medical and dental practices had a low incidence (</=0.002 annually). CONCLUSIONS: Placement of 779 AEDs in the high- and medium-incidence practices would have provided treatment for 112 patients with cardiac arrest in 7 years. To provide for the 16 cardiac arrests in low-incidence practices, an additional 1928 AEDs would be required.

Age Distribution↗

PubMed2000

Cardiopulmonary resuscitation by chest compression alone or with mouth-to-mouth ventilation.

BACKGROUND: Despite extensive training of citizens of Seattle in cardiopulmonary resuscitation (CPR), bystanders do not perform CPR in almost half of witnessed cardiac arrests. Instructions in chest compression plus mouth-to-mouth ventilation given by dispatchers over the telephone can require 2.4 minutes. In experimental studies, chest compression alone is associated with survival rates similar to those with chest compression plus mouth-to-mouth ventilation. We conducted a randomized study to compare CPR by chest compression alone with CPR by chest compression plus mouth-to-mouth ventilation. METHODS: The setting of the trial was an urban, fire-department-based, emergency-medical-care system with central dispatching. In a randomized manner, telephone dispatchers gave bystanders at the scene of apparent cardiac arrest instructions in either chest compression alone or chest compression plus mouth-to-mouth ventilation. The primary end point was survival to hospital discharge. RESULTS: Data were analyzed for 241 patients randomly assigned to receive chest compression alone and 279 assigned to chest compression plus mouth-to-mouth ventilation. Complete instructions were delivered in 62 percent of episodes for the group receiving chest compression plus mouth-to-mouth ventilation and 81 percent of episodes for the group receiving chest compression alone (P=0.005). Instructions for compression required 1.4 minutes less to complete than instructions for compression plus mouth-to-mouth ventilation. Survival to hospital discharge was better among patients assigned to chest compression alone than among those assigned to chest compression plus mouth-to-mouth ventilation (14.6 percent vs. 10.4 percent), but the difference was not statistically significant (P=0.18). CONCLUSIONS: The outcome after CPR with chest compression alone is similar to that after chest compression with mouth-to-mouth ventilation, and chest compression alone may be the preferred approach for bystanders inexperienced in CPR.

Aged↗

PubMed2000

U.S. clinical investigation of the Artisan myopia lens for the correction of high myopia in phakic eyes. Report of the results of phases 1 and 2, and interim phase 3.

PURPOSE: The purpose of this article is to present the results of the U.S. Clinical investigation of the Artisan anterior chamber iris fixed lens implant for the correction of myopia in phakic eyes. METHODS: A prospective, multi-center, FDA-supervised trial was designed and undertaken in the United States by Ophtec USA, Inc., Boca Raton, Florida to determine the safety and efficacy of the Artisan lens as a potential refractive treatment for patients with high myopia. During the trial, two different models of the Artisan lens were used: one with a 5-mm optical zone (model 206) and the other with a 6-mm optical zone (model 204). RESULTS: The data presented comprise 176 enrolled subjects and 264 implant procedures. The most frequently chosen Artisan lens power was -13.00 D (average, -12.76 D; SD, 3.24). The postoperative results at 6 months for all eyes (n = 135) showed 100% of patients were 20/40 or better best-corrected while 72% gained one or more lines and 22% gained two or more lines regardless of degree of astigmatism or postoperative goal. Through the course of the study, intraocular pressure maintained a level with a mean below 16 mmHg. In general, total reported complications in the patient cohort decreased over time, dropping from 39% at the initial visit to 10% at visit four and 0% at visit seven. CONCLUSIONS: On the basis of the interim results of the U.S. Clinical Investigation of the Artisan Myopia Lens for the Correction of High Myopia in Phakic Eyes, the Artisan anterior chamber phakic IOL may offer an option for correction of high degrees of myopia. Refractive outcomes were exceptional and complications were minimal and amenable to treatment.

Adult↗

PubMed1999

Above reproach: developing a comprehensive ethics and compliance program.

How can a healthcare organization improve the public's confidence in the conduct of its business operations? What can it do to ensure that it can thrive despite being the subject of public and governmental scrutiny and doubt? Healthcare providers must establish standards of conduct that are above reproach and ensure that those standards are clearly articulated and strictly adhered to. This article describes the merits of a comprehensive ethics and compliance program, suggests five basic elements of such a program--organizational support/structure, setting standards, creating awareness, establishing a mechanism for reporting exceptions, and monitoring and auditing--and then demonstrates how those elements should be applied in several high-risk areas. Fundamentally, an ethics and compliance program has two purposes: to ensure that all individuals in an organization observe pertinent laws and regulations in their work; and to articulate a broader set of aspirational ethical standards that are well-understood within the organization and become a practical guideline for organization members making decisions that raise ethical concerns. Every ethics and compliance program should contain certain fundamental aspects. First, the effort must have the active support of the most senior management in the organization. To instill a commitment to ethics and compliance absent a clear and outspoken commitment to such purposes by organization leaders is simply impossible. Second, an ethics and compliance program is fundamentally about organizational culture--about instilling a commitment to observe the law and, more generally, to do the right thing. Third, ethics and compliance are responsibilities of operating management (sometimes called line management). Although staff such as compliance officers are obligated to provide the necessary resources for a successful program and to design the program, such staff officers cannot achieve implementation and execution. Only operating managers can do that. Fourth, an ethics and compliance effort should be about the conduct of individuals, not about "checking the boxes" in a model plan or generating attractive written or educational materials. Such an effort is about individuals on a day-to-day basis knowing what is expected of them and doing it and about never compromising integrity, regardless of pressures faced. A great deal of progress has been made in healthcare organizations in the development of increasingly sophisticated ethics and compliance programs. A particularly energetic focus has been placed on these programs since formal government guidance regarding compliance programs was first issued in the laboratory area about two years ago and as more sophisticated automated monitoring tools have been developed. As ethics and compliance programs have become more sophisticated, certain best practices have been established. This discussion will set forth approaches to ethics and compliance in the context of what are believed to be illustrative best practices. Much of what is described here is descriptive of the efforts of Columbia/HCA Healthcare Corporation from October 1997 to the present; however, this article has been presented not as a mere descriptive piece but rather as a set of normative guidelines. We hope that other healthcare providers will find this to be of practical use. Provider settings pose certain unique challenges that are specifically addressed in this discussion; however, many of the issues raised can be adapted to other healthcare organizations. For simplicity's sake, because the authors of this article all work on a daily basis primarily with hospitals, the article is written from a hospital perspective.

Ethics, Institutional↗

PubMed1998

Investigation of lung tumour induction in C3H/HeH mice, with and without tumour promotion with urethane, following paternal X-irradiation.

In series of papers Nomura has reported that parental irradiation can lead to an enhanced incidence of lung and other tumours. However, in a recent study with BALB/cJ mice, using optimum conditions as defined by Nomura, we were unable to confirm this. We have now repeated the investigation using a different inbred strain, C3H/HeH, with and without tumour promotion in the F1 by urethane, again using protocols defined by Nomura. In a series of replicate studies spanning over 2 years, males were exposed to single, acute doses of 0, 250 and 500 cGy X-rays and thereafter placed with two females each in each of two consecutive weeks. Half the offspring from each treatment group and each week of mating were given 5 mmol/kg body weight of the urethane, while the remainder remained untreated. Most of the offspring produced were killed and scored for lung tumours at 6 months of age, while the rest were examined at 12 months of age. The proportion of fertile females and litter size provided evidence of a dose-dependent mutational response to the paternal irradiation, but no trace of a radiation-enhanced lung tumour incidence was detected among the progeny, whether in the urethane or non-urethane groups at 6 or 12 months of age, and whether assessed by numbers of mice with tumours, clusters of tumours, or cluster size. As seen in the BALB/cJ study, significant differences among different replicates were found, again suggesting a cyclical or seasonal variation in tumour incidence, but the variations seen with the two strains were not the same. The need for concurrent controls for tumour work was, nevertheless, again indicated. The overall findings do not therefore accord with those of Nomura. Furthermore, they do not support the causal association between the raised incidence of childhood leukaemia and non-Hodgkins lymphoma near Sellafield and the father's recorded radiation exposure during employment in the nuclear industry, as suggested by the Gardner report.

Animals↗

PubMed1998

Public locations of cardiac arrest. Implications for public access defibrillation.

BACKGROUND: The purpose of this study was to describe the public locations of cardiac arrest and to estimate the annual incidence of cardiac arrest per site to determine optimal placement of automatic external defibrillators (AEDs). This was a retrospective cohort study. METHODS AND RESULTS: Locations of cardiac arrest were abstracted from data collected by emergency medical service programs in Seattle and King County, Washington, from January 1, 1990, through December 31, 1994. Types of commercial and civic establishments were tallied and grouped into 23 location categories consistent with Standard Industrial Codes, and the number of sites within each location category was determined. With the addition of "public outdoors" and "automobiles" as categories, there were 25 location categories. During the study period, 7185 arrests occurred, 1130 (16%) of which were in public locations. An annual incidence of cardiac arrest per site was calculated. Ten location categories with 172 sites were identified as having a higher incidence of cardiac arrest (> or = .03 per year per site). Thirteen location categories had a lower incidence of arrest (< or = .01 per year per site). There were approximately 71,000 sites within these categories. CONCLUSIONS: Placement of 276 AEDs in the 172 higher-incidence sites would have provided treatment for 134 cardiac arrest patients in a 5-year period, 60% of whom were in ventricular fibrillation. We estimate between 8 and 32 lives could be saved in 5 years. To cover the remaining 347 arrests occurring in public in a 5-year period, defibrillators would have to be placed in 71,000 sites, not including outdoors and automobiles. Placement of AEDs in public locations can be guided by the site-specific incidence of arrest.

Electric Countershock↗

PubMed1998

Imprinting of distal mouse chromosome 2 is associated with phenotypic anomalies in utero.

Previous studies have shown that the distal region on mouse chromosome (Chr) 2 is subject to imprinting as mice with maternal duplication/paternal deficiency (MatDp.dist2) and the reciprocal (PatDp.dist2) for this region exhibit phenotypic anomalies at birth and die neonatally. We show here that imprinting effects are detectable in utero. Notably PatDp.dist2 embryos show an increase in wet weight compared with normal, which peaks at 16.5 d post coitum (dpc), and diminishes by birth, whereas the wet weight of placenta is slightly reduced in the latter half of gestation. Newborns have increased length of the long bones. By contrast, the wet weight of MatDp.dist2 embryos decreases during the second half of gestation. Measurements of dry weights of embryos at 16.5 dpc have indicated that there is no difference in either PatDp.dist2 or MatDp.dist2 compared with normal so that the wet weight differences are due to fluid retention in PatDp.dist2 but fluid loss in MatDp.dist2. In PatDp.dist2 embryos excess fluid is particularly prominent in the subcuticular skin layer, whereas by birth fluid is evident around the neck and tongue. At 16.5 dpc the PatDp.dist2 embryos are severely oedematous, as the average fluid content per unit dry weight per embryo was increased by 40%, whereas the MatDp.dist2 embryos are dehydrated as the average water content per unit dry weight per embryo was reduced by 6%. A preliminary conclusion is that there is neither growth enhancement in PatDp.dist2 nor growth retardation in MatDp.dist2 offspring.

Animals↗

PubMed1998

Covering the "open abdomen": a better technique.

"Damage control" in severe abdominal trauma, abdominal compartment syndrome, necrotizing fasciitis of the abdominal wall, and necrotizing pancreatitis often preclude closure of the fascia after laparotomy. Many techniques have been reported for temporary coverage of the exposed viscera, but most have had documented problems. We report the successful use, since 1989, of a temporary sutureless coverage. The viscera are covered with omentum when possible, then with a clear plastic sheet. Sump drains are placed over this layer. The entire abdomen is then covered with two layers of iodophor-impregnated adhesive plastic drape. The last 50 patients managed with this technique are reported. The most common indication (27 patients) was for treatment of severe abdominal trauma. There were no wound infections, fasciitis, or bowel obstruction. Eighteen patients died; no deaths were related to abdominal closure. Temporary abdominal covering with adhesive plastic sheeting is a rapid, safe, and readily available method for managing the open abdomen. This technique provides a physiologic milieu for the abdominal viscera, simplifies nursing care, and promotes safe closure of the abdomen at a later time.

Abdomen↗

PubMed1996

Diastolic blood pressure and the risk of primary cardiac arrest among pharmacologically treated hypertensive patients.

BACKGROUND: Previous studies have raised the concern that the reduction of diastolic blood pressure below 85 mm Hg among treated hypertensive patients may have cardiac hazards. However, these reports have not fully assessed potential confounding from coexisting cardiovascular disease. METHODS: We conducted a population-based case-control study to examine the relation between treated diastolic blood pressure and the risk of primary cardiac arrest among hypertensive patients free of clinically diagnosed cardiovascular disease. Cases were hypertensive enrollees of the Group Health Cooperative of Puget Sound, an HMO, who had primary cardiac arrest between 1977 and 1990 (n = 80). Control patients were a stratified random sample of hypertensive enrollees (n = 426). Ambulatory-care records were reviewed to assess blood pressures and other clinical characteristics. Medication use was assessed through the HMO computerised pharmacy database. RESULTS: Logistic regression models suggested a curvilinear relation between the level of treated diastolic blood pressure and the risk of primary cardiac arrest, after adjustment for pretreatment diastolic blood pressure, antihypertensive therapy, and other potential confounders. Compared with a treated diastolic blood pressure of 85 mm Hg, a treated diastolic blood pressure of 80 mm Hg was associated with a small increase in risk (relative risk [RR] 1.2; 95% confidence interval [CI] 1.0, 1.6), 75 mm Hg was associated with a modest increase in risk [RR 1.6; 95% CI 1.2, 2.1], and 70 mm Hg was associated with more than a twofold increase in the risk of primary cardiac arrest [RR 2.3; 95% CI 1.4; 3.8). There was little evidence of effect modification by pretreatment diastolic blood pressure. CONCLUSIONS: Our findings support available evidence that among hypertensive patients a treated diastolic blood pressure level below 85 mm Hg is associated with cardiac hazards.

Antihypertensive Agents↗

PubMed1995

Perinuclear anti-neutrophil cytoplasmic antibodies are spontaneously produced by mucosal B cells of ulcerative colitis patients.

Approximately 60% of sera from ulcerative colitis (UC) patients contains Igs reactive with neutrophil components, raising the question of the origin of these anti-neutrophil cytoplasmic Abs (ANCA). Our assertion that ANCA is a marker for a mucosal disease-related immune response predicts the existence of ANCA producing B cell clones in the lamina propria lymphocyte (LPL) fraction of UC patients. This hypothesis was tested by examining 12-day culture supernatants of LPL ANCA expression. LPL were isolated from surgically removed mucosa from patients with UC, Crohn's disease (CD), and diverticulitis. Normal mucosa was obtained from accident victims or normal margins of colon cancer resections. Supernatants were assayed by a fixed neutrophil ELISA. The ANCA staining pattern of supernatants expressing ANCA, as determined by ELISA, was assessed by indirect immunofluorescent staining of alcohol-fixed neutrophils. ANCA was found in 70% of culture supernatants from UC LPL fractions. In contrast, only approximately 11% of supernatants from CD and diverticulitis/normal (noninflammatory bowel disease (IBD)) LPL displayed ANCA binding. A perinuclear (pANCA) staining pattern was obtained with 70% of ANCA-expressing UC LPL supernatants, whereas ANCA-expressing CD and non-IBD LPL supernatants displayed a cytoplasmic reaction. PBL and mesenteric lymph node lymphocytes lacked spontaneous pANCA production, and pANCA production from PBL was not inducible. These findings indicate the existence of pANCA-producing B cell clones in mucosal lesions of UC patients and support our hypothesis that pANCA production is a consequence of a mucosal immune response specific to UC.

Autoantibodies↗

PubMed1995

Segregation of pANCA antigenic recognition by DNase treatment of neutrophils: ulcerative colitis, type 1 autoimmune hepatitis, and primary sclerosing cholangitis.

Antineutrophil cytoplasmic antibodies (ANCA) have been identified in the serum of 50-80% of ulcerative colitis (UC) patients. UC-associated ANCA yield a perinuclear staining pattern (pANCA) with alcohol-fixed neutrophils. More recently, pANCA have been detected in the serum of patients with primary sclerosing cholangitis (PSC) and other autoimmune liver diseases. Up to 70% of PSC patient sera and up to 92% of sera from patients with well-defined type 1 autoimmune hepatitis (type 1 AIH) were found to express pANCA. Such expression by patients with PSC and type 1 AIH raises questions concerning the relationship of these pANCA to each other and to that of UC. Differences and similarities in pANCA characteristics are found among the three diseases, suggesting the use of pANCA to define specific disease subgroups. Our recent finding that the UC-associated pANCA reactive antigen was localized within the nuclear domain prompted an examination of whether DNase treatment of neutrophils would alter antigenic recognition by the pANCA of UC, PSC, and type 1 AIH. While loss of antigenic recognition after DNase digestion of neutrophils was a dominant feature of the UC-associated pANCA, the majority of PSC and type 1 AIH pANCA recognized cytoplasmic constituents. These results further support the feasibility of defining and/or distinguishing disease subgroups based on the characterization of respective pANCA.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1995

Investigation of lung tumour induction in BALB/cJ mice following paternal X-irradiation.

Evidence of an enhanced incidence of lung tumours (benign adenomas and adenocarcinomas) was sought in the BALB/cJ mouse following paternal germ cell X-irradiation. In a series of replicate studies spanning approximately 1 year, males were exposed to single, acute X-ray doses of 0, 250 and 500 cGy. In each of the 2 consecutive weeks immediately thereafter they were placed with two females to generate progeny that were derived from irradiated post-meiotic cells (spermatozoa to late spermatids). These animals were then examined at 8 or 12 months for lung tumours. While the proportion of fertile females and mean litter size was affected by the radiation, showing a dose-dependent, dominant lethal response, and while cases of mutant offspring were detected, the paternal radiation did not affect lung tumour incidence in the offspring. The incidence did not vary significantly between germ cell stages irradiated (week of mating), sex of offspring, or radiation dose. However, significant differences between lung tumour incidence (mostly representing benign adenomas) were found between different replicates, these being high at the start of the study, declining and then rising to yet higher levels at its close. The finding that lung tumour incidence in BALB/cJ mice is not affected by paternal germ cell irradiation does not accord with Nomura's reports using other strains of mice. This, in turn, weakens biological support for a causal association between the raised incidence of childhood leukaemia and non-Hodgkin lymphoma near Sellafield and the father's recorded radiation exposure during employment by the nuclear industry.

Adenoma↗

PubMed1995

Molecular genetic characterization of six recessive viable alleles of the mouse agouti locus.

The agouti locus on mouse chromosome 2 encodes a secreted cysteine-rich protein of 131 amino acids that acts as a molecular switch to instruct the melanocyte to make either yellow pigment (phaeomelanin) or black pigment (eumelanin). Mutations that up-regulate agouti expression are dominant to those causing decreased expression and result in yellow coat color. Other associated effects are obesity, diabetes, and increased susceptibility to tumors. To try to define important functional domains of the agouti protein, we have analyzed the molecular defects present in a series of recessive viable agouti mutations. In total, six alleles (amJ, au, ada, a16H, a18H, ae) were examined at both the RNA and DNA level. Two of the alleles, a16H and ae, result from mutations in the agouti coding region. Four alleles (amJ, au, a18H, and ada) appear to represent regulatory mutations that down-regulate agouti expression. Interestingly, one of these mutations, a18H, also appears to cause an immunological defect in the homozygous condition. This immunological defect is somewhat analogous to that observed in motheaten (me) mutant mice. Short and long-range restriction enzyme analyses of homozygous a18H DNA are consistent with the hypothesis that a18H results from a paracentric inversion where one end of the inversion maps in the 5' regulatory region of agouti and the other end in or near a gene that is required for normal immunological function. Cloning the breakpoints of this putative inversion should allow us to identify the gene that confers this interesting immunological disorder.

Agouti Signaling Protein↗

PubMed1995

Nuclear localization of the antigen detected by ulcerative colitis-associated perinuclear antineutrophil cytoplasmic antibodies.

Antineutrophil cytoplasmic antibodies (ANCAs) identified in the serum of 50 to 80% of ulcerative colitis (UC) patients yield a perinuclear staining pattern (pANCA) with alcohol-fixed neutrophils. The ANCAs of UC are distinguishable from those described for Wegener's granulomatosis and other vasculitidies. These various non-UC ANCAs recognize neutrophil granule constituents, but the antigenic moiety specific for the UC pANCA remains unknown. Although the perinuclear nature of some ANCA reactions is an artifact of the alcohol fixation of neutrophils, which causes cytoplasmic granules to redistribute around the nucleus, the UC pANCA reaction has been found not to be similarly affected. We postulated a nuclear localization for the UC-associated pANCA antigen and used both confocal laser microscopy and immunoelectron microscopy to examine the neutrophil reaction of UC-associated pANCA-containing sera. Confocal microscopy revealed a nuclear reaction for 88% (22/25) of the sera with 72% (18/25) showing the reaction localizing to the inner side of the nuclear (membrane) periphery. Immunoelectron microscopy showed that the UC-associated pANCA reaction localized primarily over chromatin concentrated toward the nuclear periphery, although the sera did not recognize double-stranded DNA. These results confirm the nuclear localization of the UC-associated pANCA antigen.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1994

Diuretic therapy for hypertension and the risk of primary cardiac arrest.

BACKGROUND: The results of trials of the primary prevention of coronary heart disease have suggested that treating hypertension with high doses of thiazide diuretic drugs might increase the risk of sudden death from cardiac causes. In contrast, treatment with low doses of thiazide reduces the risk of coronary heart disease. METHODS: To examine the association between thiazide treatment for hypertension and the occurrence of primary cardiac arrest, we conducted a population-based case-control study among enrollees of a health maintenance organization. The case patients were 114 persons with hypertension who had a primary cardiac arrest from 1977 through 1990. The control patients were a stratified random sample of 535 persons with hypertension. The patients' treatment was assessed with the use of a computerized pharmacy data base. Records of their ambulatory care were reviewed to determine other clinical characteristics. RESULTS: The risk of primary cardiac arrest among patients receiving combined thiazide and potassium-sparing diuretic therapy was lower than that among patients treated with a thiazide without potassium-sparing therapy (odds ratio, 0.3; 95 percent confidence interval, 0.1 to 0.7). As compared with low-dose thiazide therapy (25 mg daily), moderate-dose therapy (50 mg daily) was associated with a moderate increase in risk (odds ratio, 1.7; 95 percent confidence interval, 0.7 to 4.5), and high-dose therapy (100 mg daily) was associated with a larger increase in risk (odds ratio, 3.6; 95 percent confidence interval, 1.2 to 10.8) (P value for trend, 0.02). The addition of a potassium-sparing drug to low-dose thiazide therapy was associated with a reduced risk of cardiac arrest (odds ratio, 0.4; 95 percent confidence interval, 0.1 to 1.5). CONCLUSIONS: Both the dose of thiazide drugs and the addition of potassium-sparing drugs influence the risk of primary cardiac arrest. These results may explain the differences in the effect of antihypertensive therapy on mortality from coronary heart disease in previous clinical trials.

Aged↗

PubMed1993

Analysis of childhood pedestrian deaths in New Mexico, 1986-1990.

STUDY OBJECTIVE: To determine if the mechanism of fatal childhood pedestrian injuries correlated with location, injury pattern, and age of the pedestrian and to determine ethnic differences in fatality rates. DESIGN: Retrospective review of state medical investigator reports and autopsies from 1986 to 1990. Logistic regression and chi 2 were used to test for statistically significant differences between the groups in our data set. TYPE OF PARTICIPANTS: New Mexican children, 0 to 14 years old fatally injured by moving vehicles. RESULTS: Sixty-four children died for an overall fatality rate of 3.8 (per 100,000). Native American children and children younger than 5 years experienced the highest fatality rates. Children younger than 5 years were more likely to be crushed under the wheels of a slow-moving vehicle in both a nontraffic and a traffic location, whereas older children were found more often to have died from injuries from a high-speed impact event in a traffic location (P < .001). Leg fractures (P = .001) and spinal fractures (P = .02) occurred more frequently in impact than crush injuries. CONCLUSION: Young children are at risk for a crush injury in both the traffic and nontraffic environment.

Accidents, Traffic↗

PubMed1993

Socioeconomic status and prediction of ventricular fibrillation survival.

OBJECTIVES: The association between socioeconomic status and cardiac arrest is less well known than some other associations with cardiac arrest. We used property tax assessments as a measure of socioeconomic status in a study of victims of out-of-hospital cardiac arrest found in ventricular fibrillation. METHODS: We studied patients attended by the Seattle Fire Department's emergency medical services system between May 1986 and August 1988. During the period studied, 356 episodes met the study criteria; 114 (32%) of these patients survived without major neurologic deficit. Residential property tax assessments were available for 253 of the patients. RESULTS: After adjustments were made for age, witnessed collapse, bystander-initiated cardiopulmonary resuscitation, time from call to paramedic arrival, activity, location of collapse, and chronic morbidity, an association of survival with greater assessed value per living unit was observed. An increase of $50,000 in value per unit was associated with a 1.6-fold increase in survival rate. CONCLUSIONS: Not only are persons in the lower socioeconomic strata at greater risk for cardiac mortality, but they are also less likely to survive an episode of out-of-hospital cardiac arrest.

Aged↗