Trauma-related hospitalizations among urban adolescents in New Zealand: priorities for prevention

PURPOSE

To: (a) determine the magnitude, characteristics, and in-patient costs of injury among hospitalized urban adolescents in New Zealand (NZ); (b) identify regional priorities for injury prevention and investigative research; and (c) compare the study findings with published data from other industrialized countries.

METHODS

The 1989-1993 files of the NZ Hospital Discharge Database were accessed to identify and analyze trauma-related admissions of adolescents residing in NZ's largest metropolitan region.

RESULTS

The estimated 9569 hospitalizations for injury accounted for one-fourth of all adolescent admissions in the region, a mean annual hospitalization rate of 1292/100,000 population and a minimum annual cost of NZ $5.8 million for in-patient care. Males and indigenous Maori youth had comparatively higher rates of hospitalizations for most major causes of injury. Falls, pedal cyclist injury, cuts, and piercing injuries were leading causes of hospitalization for trauma in early adolescence. Admission rates for motorcylist and other motor vehicle occupant trauma and self-inflicted injury increased substantially among older adolescents. Sport and recreational activities comprised at least one-sixth of injury admissions.

CONCLUSIONS

The overall rates of injury resulting in hospitalization among Auckland adolescents were comparable to those reported from Australia and France, but higher than those from the United States, Canada, and Israel. By identifying priority issues and high-risk groups, this study provides a foundation for regional injury control initiatives. It also demonstrates the utility and limitations of E-coded hospital discharge registries in defining the burden of serious nonfatal trauma.

Nonsteroidal anti-inflammatory drugs attenuate epidermal growth factor-induced proliferation independent of prostaglandin synthesis inhibition

BACKGROUND

The mechanism(s) whereby nonsteroidal anti-inflammatory drugs (NSAIDs) attenuate colorectal tumor growth remains poorly understood. This study determined if NSAIDs decreased epidermal growth factor (EGF)-induced proliferation in human colonic tumor (Caco-2) cells and whether this process involved the inhibition of prostaglandin (PG) synthesis.

METHODS

Caco-2 cells were serum-starved (48 h) and subsequently treated (48 h) with either serum-free media or EGF (10 ng/ml) +/- physiologic and noninjurious (as determined by LDH release) concentrations of aspirin, indomethacin, and ibuprofen. PG synthesis was measured by EIA. Proliferation was quantitated with two assays: cellular protein and nucleic acid content.

RESULTS

NSAID treatment did not inhibit growth in cells treated with only serum-free media. Cells exposed to EGF demonstrated a significant increase in PGE2, protein, and nucleic acid. Levels of other eicosanoids (PGI2, TXA2) were minimal both before and after EGF treatment. Despite varying degrees of PGE2 inhibition, each NSAID group equally attenuated EGF-induced protein and nucleic acid synthesis. The correlation between PGE2 levels and protein (R2 = 0.56) or nucleic acid (R2 = 0.54) was poor. Finally, the addition of a physiologically appropriate concentration of exogenous PGE2 failed to reverse NSAID-induced growth inhibition.

CONCLUSION

These data suggest that NSAIDs, independent of PG synthesis inhibition, attenuate EGF-induced proliferation in Caco-2 cells. This may provide one explanation for how NSAIDs limit colonic neoplasia.

Fatal nontraffic injuries involving alcohol: A metaanalysis

STUDY OBJECTIVE

Estimates of alcohol involvement in fatal injuries vary widely. For injuries other than those involving motor vehicles, no national data exist and the quality of regional data is limited. This study synthesizes US medical examiner studies of nontraffic fatalities for the purpose of estimating alcohol involvement by injury mechanism and intent.

METHODS

We reviewed 331 medical examiner studies published between 1975 and 1995 that reported nontraffic injury fatalities. These studies were identified from computerized bibliographic databases and by hand searching of reference lists from 26 review publications and the subject indices of 7 prominent journals. A final total of 65 articles (19.6%) met our inclusion criteria for analysis. National data on motor vehicle fatalities were used for comparison.

RESULTS

A total of 7,459 unintentional injury deaths, 28,696 homicide cases, and 19,347 suicide cases were aggregated. The aggregate percentage tested for blood alcohol concentration (BAC) was highest among homicide cases (88.2%), followed by unintentional injury deaths (84.0%) and suicide cases (81.7%). The aggregate percentage determined to be intoxicated (BAC, >/=100 mg/dL) was highest among homicide cases (31.5%), followed by unintentional injury deaths (31.0%) and suicide cases (22.7%). Mean and median comparisons produced comparable findings. Fewer than one quarter of the 65 articles reported gender- and age-specific rates. Inconsistent reporting of gender and age-specific rates in fatal nontraffic injuries prevented their analysis by cause of death. Fatally injured motor vehicle drivers, however, demonstrated distinct variation in alcohol involvement by age and gender.

CONCLUSION

This metaanalysis is the first systematic attempt to estimate alcohol involvement in fatal nontraffic injuries at the national level. It demonstrates that alcohol is an important factor in many fatal injuries and that its importance varies by cause of injury.

Cerebral glucose metabolic response to combined total sleep deprivation and antidepressant treatment in geriatric depression

OBJECTIVE

The treatment of geriatric depression is complicated by a variable and delayed response to antidepressant treatment. The present study was undertaken to test the hypothesis that combined total sleep deprivation and paroxetine treatment would produce a persistent reduction in glucose metabolism in the anterior cingulate cortex similar to that reported after long-term antidepressant treatment.

METHOD

Six elderly depressed patients who met the DSM-IV criteria for major depressive disorder and six age-matched comparison subjects underwent serial positron emission tomography (PET) studies at baseline, after total sleep deprivation, after recovery sleep (after the initial paroxetine dose), and after 2 weeks of paroxetine treatment (patients only). The PET data were analyzed by using statistical parametric mapping methods.

RESULTS

The patients' scores on a 13-item version of the Hamilton Depression Rating Scale were decreased after total sleep deprivation, after recovery sleep, and after 2 weeks of treatment. The Hamilton depression scores of the comparison subjects were not significantly altered. In the patients, the greatest reductions in normalized, relative glucose metabolism after sleep deprivation were observed in the anterior cingulate cortex (Brodmann area 24), and they persisted after recovery sleep and antidepressant treatment. The comparison subjects demonstrated increased metabolism in these areas.

CONCLUSIONS

Improvement in the patients' depressive symptoms was accompanied by reduced glucose metabolism in the right anterior cingulate cortex and right medial frontal cortex. These preliminary data indicate that in elderly depressed patients, total sleep deprivation may accelerate the clinical and glucose metabolic response to antidepressant treatment.

Calcium accentuates injury induced by ethanol in human gastric cells

The mechanism(s) whereby ethanol induces cellular injury remains poorly understood. Furthermore, the role of calcium in gastric mucosal injury under in vitro conditions is poorly defined. The major objectives of this study were to (1) define the temporal relationship between intracellular calcium accumulation induced by ethanol and cellular injury, (2) characterize the mechanism(s) whereby ethanol increases cellular calcium content, and (3) determine whether calcium removal would attenuate ethanol-induced cellular injury. Human gastric cells (AGS) were used for all experiments. Sustained intracellular calcium accumulation induced by ethanol, but not transient changes, preceded and directly correlated with cellular injury. Cells exposed to damaging concentrations of ethanol demonstrated an initial calcium surge that appeared to be a consequence of inositol 1,4,5-triphosphate (IP3) generation and subsequent internal store release followed by a sustained plateau resulting from extracellular calcium influx through store-operated calcium channels. Finally, both morphologic (cellular injury) and functional (clearance of bovine serum albumin) changes induced by ethanol were significantly attenuated when extracellular Ca(+&plus) influx was prevented, and further decreased when intracellular Ca(++) stores were depleted. These data indicate that calcium plays a significant role in cellular injury induced by ethanol.

Prostaglandins protect human intestinal cells against ethanol injury by stabilizing microtubules: role of protein kinase C and enhanced calcium efflux

Prostaglandins (PG) protect gastrointestinal cells against damage induced by ethanol (EtOH) and other noxious agents, a process termed cytoprotection. The present study investigated the relationships between microtubule (MT) stability, protein kinase C (PKC) activation, and calcium efflux as a possible mechanism of PG's protective action using a human colonic cell line (Caco-2) exposed to known damaging concentrations of EtOH (7.5% and 10%). Preincubation of Caco-2 cells with 16,16-dimethyl-PGE2 (PG, 2.6 microM) significantly increased PKC activity in these cells. Pretreatment of Caco-2 cells with 50 microM OAG (a synthetic diacylglycerol and PKC activator) or 30 nM TPA (a direct PKC activator) prior to exposure to 7.5% or 10% EtOH for 5 min significantly reduced cell injury, as determined by trypan blue exclusion, and increased MT stability, as confirmed by confocal microscopy. Pretreatment of Caco-2 cells with 4 alpha-PDD (an inactive phorbol ester, 20 nM) failed to prevent cell injury and disruption of the MT cytoskeleton. Preincubation with staurosporine (a PKC inhibitor, 3 nM) abolished the protective effects of PG in cells exposed to 7.5% and 10% EtOH. Incubation of Caco-2 cells with A23187 (a Ca2+ ionophore), similar to 10% EtOH, caused a significant reduction in cell viability and MT stability. Preincubation with A23187 in combination with PG or OAG prior to subsequent exposure to EtOH significantly abolished the protective effects of PG or OAG pretreatment. Finally, pretreatment with OAG, TPA, or PG resulted in significant increases in calcium-45 efflux, which correlated with increased stability of the MT cytoskeleton. These data suggest that PG possesses direct protective effects against EtOH injury in Caco-2 cells and may act by stabilizing MT through the PKC signal transduction pathway and/or stimulation of calcium efflux from the cells.

Test-retest variability of serotonin 5-HT2A receptor binding measured with positron emission tomography and [18F]altanserin in the human brain

The role of serotonin in CNS function and in many neuropsychiatric diseases (e.g., schizophrenia, affective disorders, degenerative dementias) support the development of a reliable measure of serotonin receptor binding in vivo in human subjects. To this end, the regional distribution and intrasubject test-retest variability of the binding of [18F]altanserin were measured as important steps in the further development of [18F]altanserin as a radiotracer for positron emission tomography (PET) studies of the serotonin 5-HT2A receptor. Two high specific activity [18F]altanserin PET studies were performed in normal control subjects (n = 8) on two separate days (2-16 days apart). Regional specific binding was assessed by distribution volume (DV), estimates that were derived using a conventional four compartment (4C) model, and the Logan graphical analysis method. For both analysis methods, levels of [18F]altanserin binding were highest in cortical areas, lower in the striatum and thalamus, and lowest in the cerebellum. Similar average differences of 13% or less were observed for the 4C model DV determined in regions with high receptor concentrations with greater variability in regions with low concentrations (16-20%). For all regions, the absolute value of the test-retest differences in the Logan DV values averaged 12% or less. The test-retest differences in the DV ratios (regional DV values normalized to the cerebellar DV) determined by both data analysis methods averaged less than 10%. The regional [18F]altanserin DV values using both of these methods were significantly correlated with literature-based values of the regional concentrations of 5-HT2A receptors determined by postmortem autoradiographic studies (r2 = 0.95, P < 0.001 for the 4C model and r2 = 0.96, P < 0.001 for the Logan method). Brain uptake studies in rats demonstrated that two different radiolabeled metabolites of [18F]altanserin (present at levels of 3-25% of the total radioactivity in human plasma 10-120 min postinjection) were able to penetrate the blood-brain barrier. However, neither of these radiolabeled metabolites bound specifically to the 5-HT2A receptor and did not interfere with the interpretation of regional [18F]altanserin-specific binding parameters obtained using either a conventional 4C model or the Logan graphical analysis method. In summary, these results demonstrate that the test-retest variability of [18F]altanserin-specific binding is comparable to that of other PET radiotracers and that the regional specific binding of [18F]altanserin in human brain was correlated with the known regional distribution of 5-HT2A receptors. These findings support the usefulness of [18F]altanserin as a radioligand for PET studies of 5-HT2A receptors.

Role of neutrophils in hepatotoxicity induced by oral acetaminophen administration in rats

Acetaminophen (APAP) is a common analgesic and antipyretic compound which, when administered in high doses, has been associated with significant morbidity and mortality, secondary to hepatic toxicity. To date, the mechanism(s) whereby APAP induces liver injury remains to be delineated. This study investigated the potential role of neutrophils as contributors to liver injury in rats administered sublethal doses of APAP. Oral APAP administration (650 mg/kg) was associated with increases in serum alanine transaminase (ALT) levels indicating biochemical evidence of significant liver damage. Furthermore, histological analyses verified significant hepatocellular necrosis as well as enhanced myeloperoxidase staining in these liver specimens. However, if animals were pretreated with antineutrophil sera prior to APAP administration, neutrophil counts remained depressed, ALT levels were significantly decreased, and the degree of liver injury was attenuated on a histological level. Taken together these data suggest that neutrophils mediate, at least in part, the hepatotoxic effects of oral acetaminophen administration in rats.

Structural studies of polymer-cushioned lipid bilayers

The structure of softly supported polymer-cushioned lipid bilayers, prepared in two different ways at the quartz-solution interface, were determined using neutron reflectometry. The polymer cushion consisted of a thin layer of branched, cationic polyethyleneimine (PEI), and the bilayers were formed by adsorption of small unilamellar dimyristoylphosphatidylcholine (DMPC) vesicles. When vesicles were first allowed to adsorb to a bare quartz substrate, an almost perfect bilayer formed. When the polymer was then added to the aqueous solution, it appeared to diffuse beneath this bilayer, effectively lifting it from the substrate. In contrast, if the polymer layer is adsorbed first to the bare quartz substrate followed by addition of vesicles to the solution, there is very little interaction of the vesicles with the polymer layer, and the result is a complex structure most likely consisting of patchy multilayers or adsorbed vesicles.

A neutron reflectivity study of polymer-modified phospholipid monolayers at the solid-solution interface: polyethylene glycol-lipids on silane-modified substrates

The structure of polymer-decorated phospholipid monolayers at the solid-solution interface was investigated using neutron reflectometry. The monolayers were composed of distearoylphosphatidylethanolamine (DSPE) matrixed with varying amounts of DSPE-PEG (DSPE with polyethylene glycol covalently grafted to its headgroup). Mixed lipid monolayers were Langmuir-Blodgett deposited onto hydrophobic quartz or silicon substrates, previously hydrophobized by chemically grafting a robust monolayer of octadecyltrichlorosilane (OTS). We show that this method results in homogeneous and continuous phospholipid monolayers on the silanated substrates and determine that the grafted PEG chains extend away from the monolayers into the solvent phase as a function of their density, as expected from scaling theories. In addition, ligands were coupled to the end of the PEG chains and selective binding was demonstrated using fluorescence microscopy. Our results demonstrate that these constructs are ideal for further characterization and studies with well-defined monomolecular films.

Screening trauma patients for alcoholism according to NIAAA guidelines with alcohol use disorders identification test questions

Drinking pattern criteria (drinking frequency and number of drinks per occasion) issued by the National Institute on Alcohol and Abuse and Alcoholism (NIAAA) to screen primary practice patients for alcohol problems were evaluated in 1216 injured patients treated in a regional trauma center. Vehicular crash victims predominated (50.2%, of whom 64.5% were drivers), followed by victims of violence (31.2%) and nonviolent-injury victims (18.5%). Alcohol Use Disorders Identification Test (AUDIT) questions #1 (drinking frequency) and #2 (drinks/day) were used to assess the patients for current alcohol dependence (CAD). AUDIT responses roughly approximating NIAAA guidelines (high threshold: drinks > or = 4 times/week, > or = 5 drinks/day) and those indicating less drinking (low threshold: drinks > or = 2-3 times/ week, > or = 3 drinks/day) were chosen. Comparisons were made relative to sensitivity and specificity of responses in detecting CAD. When low threshold responses were used for either question, sensitivity to detect CAD increased overall (#1 from 0.53 to 0.80, #2 from 0.62 to 0.88) as well as among the subgroups of patients, whereas specificity remained high or at acceptable levels overall (#1 from 0.95 to 0.82, #2 from 0.92 to 0.71) and among the subgroups of patients. Study findings suggest that, among injured drivers and other groups of trauma center patients, lesser amounts of drinking should be used as screening criteria for CAD than are used for the general population.

Acute traumatic injuries in automotive manufacturing

Motor vehicle manufacturing, with its varied tasks, challenging work environment, and diverse worker populations, presents many hazards to employees. This study examined routinely collected surveillance data from a major motor vehicle manufacturer to identify injury types, high-risk workers, causes of injury, and factors associated with work loss. Injury and personnel data were used to calculate injury rates. Injury data were from the routinely collected medical and safety surveillance system on occupational injuries. The number of persons working in the plants was estimated using year-end personnel reports. Key word searches supplementing the analyses provided insight into the specific circumstances of injury. The most common injuries were sprains/strains (39% of the total), lacerations (22%), and contusions (15%). Forty-nine percent of the injuries resulted in one or more lost or restricted workdays; 25% resulted in 7 or more lost or restricted workdays. The injuries most likely to result in work loss were amputations, hernias and fractures. Sprains/strains accounted for 65% of all lost workdays. Injury rates ranged from 13.8 per 100 person-years at stamping plants to 28.7 at parts depots. Even within similar types of plants, injury rates varied widely, with a twofold difference among the individual assembly plants in overall injury rates. Injury surveillance systems with descriptive data on injury events shed light on the circumstances under which certain types of injuries occur and can provide the basis for preventive interventions. Sources of variation and potential biases are discussed, providing guidance for those interested in designing and using surveillance systems for occupational injuries.

Indomethacin increases susceptibility to injury in human gastric cells independent of PG synthesis inhibition

Indomethacin and other nonsteroidal anti-inflammatory drugs are commonly used to indirectly deduce the possible role of PGs in a process being studied. The objective of this study was to determine if indomethacin, at concentrations comparable to plasma and tissue levels obtained in humans taking therapeutic doses, predisposes human gastric cells to injury through inhibition of PGs or acts through an alternate mechanism. The role of intracellular Ca2+ in this damaging process was also assessed. Indomethacin pretreatment, although by itself nondamaging, was associated with elevated intracellular Ca2+ concentrations and an increased cellular permeability, an effect that was dependent on extracellular Ca2+. Furthermore, indomethacin pretreatment significantly predisposed AGS cells to injury induced by two dissimilar agents (deoxycholate and A-23187), both of which are associated with intracellular Ca2+ accumulation. The addition of exogenous PGs did not reverse the predisposition to injury induced by indomethacin. The observed effects of indomethacin were dependent on concentration and not on ability to inhibit PG synthesis. Similar effects were not observed with equipotent concentrations of ibuprofen or aspirin. Finally, the exacerbation of deoxycholate-induced injury induced by indomethacin was not observed when extracellular Ca2+ was removed. Indomethacin, by disturbing intracellular Ca2+ homeostasis, predisposes human gastric cells to injury through mechanisms independent of PG synthesis. The current study suggests that data resulting from studies employing only indomethacin as a PG synthesis inhibitor should be interpreted with caution.

Creating injury episodes using medical claims data

BACKGROUND

Health care episodes are traditionally created for a specific condition using defined relevant diagnosis and procedure codes and a start and end period. Our goal is to use 1987 to 1989 medical claims data to create distinct episodes of care as a result of injury.

METHODS

Claims for 102,000 people younger than 65 years were obtained from Medstat Systems, Inc. Injury claims were identified by International Classification of Diseases, 9th Revision, Clinical Modification diagnosis codes and separated into 10 body regions. Using linked inpatient and outpatient claims data, we established clear zones--a maximum period for a return visit for medical treatment--for each of 10 body regions injured by hospitalization status. These clear zones were used to create episodes of injury.

RESULTS

A total of 295,165 injury claims created 79,564 episodes of injury. Limb and trunk injuries typically have the most follow-ups in terms of number of claims and spacing between claims. Brain injuries, even for admitted patients, result in an average of fewer than two follow-up claims. On average, hospitalized patients require only one more follow-up than nonadmitted patients.

CONCLUSIONS

This paper presents a method for identifying injury episodes using a medical claims database. The analysis suggests that follow-up to check for minor long-term sequelae of brain injury is rare.

Harstad injury prevention study: prevention of burns in young children by community based intervention

OBJECTIVE

To describe the long term effectiveness of a community based program targeting prevention of burns in young children.

DESIGN

Quasiexperimental.

SETTING

The Norwegian city of Harstad (main intervention), six surrounding municipalities (intervention diffusion), and Trondheim (reference).

PARTICIPANTS

Children under age 5 years in the three study populations.

METHODS

Outpatient and inpatient hospital data were coded according to the Nordic system, and collected as part of a national injury surveillance system. Burn data collection started in May 1985. The first 19.5 months of the study provided baseline data, while the last 10 years involved community based intervention, using a mix of passive and active interventions.

RESULTS

The mean burn injury rate decreased by 51.5% after the implementation of the intervention in Harstad (p < 0.05) and by 40.1% in the six municipalities (not significant). Rates in the reference city, Trondheim, increased 18.1% (not significant). In Harstad and the six surrounding municipalities there was a considerable reduction in hospital admissions, operations, and bed days. Interventions with passive strategies were more effective, stove and tap water burns being eliminated in the last four years, while active strategies were less effective.

CONCLUSIONS

A program targeting burns in children can be effective and sustainable. Local injury data provided the stimulus for community action.

Role of calcium in adaptive cytoprotection and cell injury induced by deoxycholate in human gastric cells

We have developed an in vitro model of adaptive cytoprotection induced by deoxycholate (DC) in human gastric cells and have shown that pretreatment with a low concentration of DC (mild irritant, 50 microM) significantly attenuates injury induced by a damaging concentration of DC (250 microM). This study was undertaken to assess the effect of the mild irritant on changes in intracellular Ca2+ and to determine if these perturbations account for its protective action. Protection conferred by the mild irritant was lost when any of its effects on intracellular Ca2+ were prevented: internal Ca2+ store release via phospholipase C and inositol 1,4, 5-trisphosphate sustained Ca2+ influx through store-operated Ca2+ channels or eventual Ca2+ efflux. We also investigated the relationship between Ca2+ accumulation and cellular injury induced by damaging concentrations of DC. In cells exposed to high concentrations of DC, sustained Ca2+ accumulation as a result of extracellular Ca2+ influx, but not transient changes in intracellular Ca2+ content, appeared to precede and induce cellular injury. We propose that the mild irritant disrupts normal Ca2+ homeostasis and that this perturbation elicits a cellular response (involving active Ca2+ efflux) that subsequently provides a protective action by limiting the magnitude of intracellular Ca2+ accumulation.

Evaluation of narrative text for case finding: the need for accuracy measurement

This article reviews the analysis of a narrative text electronic search technique being used in the insurance industry. We reviewed a previously published study of motor vehicle crashes in roadway construction workzones as well as additional data supplied by the authors with respect to the methods of keyword selection. The narrative text search technique was evaluated with decision statistics and was found to have a sensitivity of 92.3%, 95% confidence interval 67.5%-99.6%. This range of sensitivity, at its most extreme value, led to a 32.5% underestimation of claims prevalence. Furthermore, because the electronic search developed two classification categories from a limited text field (approximately 20 words), only half of the cases had at least one classification. Systematic error estimates were used to obtain true population proportions for crash characteristics, revealing significant underestimations in costs. This analysis highlights the need for investigators to apply decision statistics to narrative text searching techniques when they are used essentially as diagnostic test procedures on insurance claims datasets.

Store-operated calcium influx in human gastric cells: role of endogenous prostaglandins

BACKGROUND

Store-operated calcium influx (SOCI) appears to be a key component in regulating processes such as gene expression and cellular metabolism in nonexcitable cells. Our objective was to determine what effect, if any, prostaglandin inhibition had on SOCI in human gastric cells.

METHODS

SOCI was induced in human gastric cells (AGS) with thapsigargin, a microsomal Ca++ adenosine triphosphatase inhibitor. Quantitation of SOCI was achieved by two different methods: sustained intracellular calcium elevation and manganese (Mn++) uptake. Endogenous prostaglandin E2 (PGE2) synthesis was measured by enzyme immunoassay. Three different nonsteroidal anti-inflammatory drugs (NSAIDs; indomethacin, ibuprofen, and aspirin) were used to minimize the nonspecific actions of any individual agent.

RESULTS

SOCI in AGS cells was inhibited by the store-operated Ca+2 channel blocker lanthanum (La+3) but not the voltage-operated Ca+2 channel antagonists verapamil or nifedipine. Each of the three NSAIDs equally inhibited SOCI. The inhibition of SOCI induced by indomethacin was partially reversed by the addition of exogenous PGE2. Finally, AGS cells exposed to thapsigargin demonstrated significantly increased endogenous PGE2 release.

CONCLUSIONS

These data suggest that NSAIDs inhibit (or endogenous prostaglandins modulate) SOCI in human gastric cells, at least in part. Because SOCI appears to be a critical mechanism involved in cell proliferation, this may provide one explanation of how NSAIDs inhibit (and endogenous prostaglandins enhance) gastric epithelial renewal and repair.

A prospective cohort study of blood donors: methodological issues in the investigation of injuries and chronic diseases

Blood donors have made important contributions to research, most notably in cross-sectional seroprevalence studies. The proposed New Zealand Blood Donors Health Study is a prospective cohort study of 30,000 New Zealand donors designed to investigate the determinants of common injuries, cardiovascular disease and cancer. While robust from an analytic perspective, the execution of prospective cohort studies in many settings is impeded by methodological, economic and organisational barriers. We examined the operational considerations of implementing a large-scale cohort study at a transfusion centre and evaluated measures taken to optimise data collection procedures. A pilot study of 1,000 participants revealed donor motivation to participate in this research was high (91% response rate). Comprehensive exposure data on lifestyle, behavioural and psychosocial factors were obtained from 95% of participants. Substantial heterogeneity in levels of potential risk factors was noted among respondents. Detailed dietary habit information and a study blood sample were obtained from 67% and 100% of participants, respectively. Study recruitment and baseline data collection was feasible during routine donor visits with minimal interruption to donor centre staff and procedures. We conclude the study design and characteristics of the regional donor program enhance the efficiency and significance of the proposed research.

Adaptive cytoprotection induced by ethanol in human intestinal cells: role of prostaglandins and calcium homeostasis

OBJECTIVE

To determine whether adaptive cytoprotection exists in human intestinal cells under in vitro conditions and what role, if any, endogenous prostaglandins or calcium may play in mediating this protective response.

SUMMARY BACKGROUND DATA

Adaptive cytoprotection can be defined as that process whereby the administration of a low concentration of a damaging agent, termed a "mild irritant," which by itself is not injurious, can attenuate gastrointestinal mucosal injury subsequently induced by the application of higher concentrations of the same or other necrotizing agents. Despite substantial investigation, the mediator or mediators of adaptive cytoprotection remain poorly understood.

METHODS

Postconfluent Caco-2 cells were used in all experiments. Cellular death was quantitated using a dual-component fluorescent assay. Changes in intracellular calcium concentration were quantitated by measuring fluorescent signal changes of the single wavelength calcium indicator (Fluo-3). Finally, prostaglandin E2 release into the media was quantitated by radioimmunoassay.

RESULTS

Pretreatment of Caco-2 cells with low concentrations of ethanol (mild irritant) significantly attenuated injury induced by higher damaging concentrations of ethanol. The protection conferred by the mild irritant was directly dependent on both the concentration of the irritant used and the duration of exposure and was abrogated when cells were pretreated with an endogenous prostaglandin inhibitor (indomethacin) or if the mild irritant was administered in calcium-free media. Cells exposed to ethanol had a significant and concentration-dependent increase in intracellular calcium concentration, an effect that was highly related to cellular injury. Pretreatment with a mild irritant significantly decreased intracellular calcium increases induced by not only ethanol but also by a calcium ionophore (A23187). Cells treated with low concentrations of ethanol demonstrated no significant elevation in prostaglandin E2 release.

CONCLUSIONS

Adaptive cytoprotection induced by ethanol exists in human colonocytes under in vitro conditions independent of mucosal blood flow, neural innervation, or circulating humoral factors. The authors' data suggest that this response does not require endogenous prostaglandin synthesis but may involve processes whereby intracellular calcium accumulation is prevented.

Hepatic infarction secondary to arterial insufficiency in native livers: CT findings in 10 patients

PURPOSE

To describe the computed tomographic (CT) appearance of hepatic infarcts resulting from arterial insufficiency in native livers.

MATERIALS AND METHODS

The authors retrospectively reviewed the clinical and imaging findings in 10 patients (five men, five women; age range, 28-70 years) with 14 hepatic infarcts seen over 3 years. CT scans were analyzed for infarct appearance, vessel patency, and evolution of infarct pattern over time.

RESULTS

Hepatic infarction resulted from hepatobiliary surgery (n = 6), radiologic intervention (n = 3), and celiac occlusion secondary to antiphospholipid syndrome (n = 1). All 14 infarcts were of low attenuation, peripheral, and wedge-shaped. Occluded arterial vessels were identified in eight patients. Follow-up CT revealed infarct diminution with parenchymal atrophy and scarring (n = 5), progressive liquefaction (n = 2), or both parenchymal atrophy and progressive liquefaction (n = 1).

CONCLUSION

Sudden interruption of hepatic arterial flow may cause acute native liver infarction. Patients at risk include those with underlying vascular disease who undergo complicated surgical procedures and those undergoing peripheral arterial embolization.

Hypoxia-reoxygenation potentiates zymosan activated plasma-induced endothelial injury

The pathophysiology of ischemia-reperfusion injury and the role played by the interaction of plasma proteins, including complement, with reperfused endothelium remains incompletely understood. Venular endothelial changes due to hypoxia followed by reoxygenation (H-R) are vital because venules are the primary site of fluid accumulation and polymorphonuclear leukocyte deposition due to inflammation. This investigation focused on whether H-R potentiates the response to permeability inducing agents found in activated plasma. Activated complement was studied by using zymosan activated plasma (ZAP). Permeability changes were assessed by quantitating rate of clearance of albumin across the monolayers. H-R alone did not change permeability relative to the normoxic condition. ZAP at 2% in normoxic cells increased albumin clearance from 2 +/- 0.2 to 9 +/- 1. 0 microL/h, which increased significantly to 13.5 +/- 2.0 microL/h when given to hypoxia-reoxygenation challenged monolayers. The permeability response to ZAP was dose related and not present with heat inactivated ZAP. ZAP at 2% altered the structure of the cytoskeleton of the human umbilical vein endothelial cells (HUVEC). However, addition of monoclonal anti-complement antibodies or addition of soluble complement receptor-1 did not attenuate ZAP-induced HUVEC permeability. Addition of zymosan-activated serum did not alter the permeability and addition of heparin inhibited the ZAP-induced changes in permeability, suggesting that these changes were mediated via thrombin and not complement. The increase in monolayer permeability due to ZAP was prevented by increasing intracellular adenosine-3',5'-cyclic monophosphate. These findings suggest that HUVEC monolayers challenged with H-R are more susceptible to increases in permeability induced by activated plasma components.

Drowning surveillance: how well do E codes identify submersion fatalities

OBJECTIVES

The aim was to determine in New Zealand: (1) to what degree the International Classification of Diseases Supplementary Classification (ICD) external cause (E) codes for drowning identify all deaths involving drowning; (2) how the other drowning deaths are distributed across E codes; and (3) whether the proportion of drownings not identified by traditional ICD E codes has changed over time.

METHODS

Mortality files for the period 1977-92, which were coded in the range E800-E999 (external causes of injury and poisoning), were searched electronically using the keyword "drown".

RESULTS

2718 cases that involved drowning were identified. This represents a 17.7% increase in the number of cases one would identify using ICD drowning E codes alone. The majority (65%) of the 408 drownings not coded as such were coded as motor vehicle traffic crashes. The number of drownings that were not identified by ICD E codes remained relatively constant over time, although the number of deaths E coded as drowning declined significantly in recent years.

CONCLUSION

Standard ICD E codes for drowning do not identify all drowning related deaths, which may make comparisons of injury rates between countries difficult, especially for injuries such as drownings and burns that can be both nature of injury and external cause codes. Multiple cause coding and the inclusion of free text narratives are an important tool to improve the value of a country's vital statistics for injury prevention, and facilitate comparisons with other countries.

Comparison of sonograms and liver histologic findings in patients with chronic hepatitis C virus infection

Gray scale ultrasonographic images of the liver were correlated with histologic findings in patients with chronic hepatitis C virus infection. The gray scale patterns of 64 livers with chronic hepatitis C virus infection were categorized as normal, fatty, fibrofatty, fibrotic, or inflammatory and were graded as mild, moderate, or severe. Liver biopsy specimens also were analyzed for the presence of fat, inflammation, and fibrosis and graded similarly. No correlation was found between fatty and fibrofatty sonographic findings with any of the three histologic patterns. Correlations were found between fibrotic sonographic findings and both fibrotic and inflammatory histologic findings (r = 0.27; P = 0.03). Although some pathologic features of liver disease were detected by ultrasonography, no useful correlation was noted between results of sonography and histologic examination.

Arteriopathy induced by an adenosine agonist-antihypertensive in monkeys

An adenosine agonist, designated chemically as (R)-N-(2,3-dihydro-1H-inden-1-yl) adenosine or CI-947, was administered orally to 2 males and 2 female cynomolgus monkeys each at 5, 10, 20, and 50 mg/kg of body weight for 2 wk. One male and 1 female given 50 mg/kg were euthanatized on days 10 and 8, respectively, because of poor clinical condition. Emesis was present at 10, 20, and 50 mg/kg. Decreased heart rate and QT prolongation were present at 50 mg/kg. Extramural coronary arterial lesions consisting of medial necrosis with cellular debris and mixed inflammatory cell response in the intima, media, and adventitia were present in 1 male at 20 mg/kg and 1 male at 50 mg/kg at study termination. Similar arterial lesions were present in the small and large intestines and testis of the male at 50 mg/kg. Colonic mucosal erosions with mixed inflammatory cell infiltrates in the lamina propria were seen in this male and in all CI-947 treated females at 10, 20, and 50 mg/kg. Myocardial degeneration and necrosis of myocardial fibers with mononuclear cell infiltrates in the interstititum were noted in the left ventricle of 1 female at 20 mg/kg and in all animals at 50 mg/kg. Renal cortical tubular dilatation with increases in serum creatinine and/or blood urea nitrogen were noted in a control female and animals at 10 and 50 mg/kg. Plasma CI-947 concentration increased with increasing dose. Coronary vascular injury in the monkey was similar to the arterial lesion in CI-947-treated dogs and may relate to the pharmacologic/hemodynamic effects induced by CI-947. When compared with the dog, the monkey appears to be less sensitive to development of arteriopathy, as indicated by lower incidence, at similar systemic exposure levels.

Adaptive cytoprotection against deoxycholate-induced injury in human gastric cells in vitro: is there a role for endogenous prostaglandins?

The majority of previous work investigating adaptive cytoprotection has involved in vivo studies, which have suggested that this protective response is in large part mediated by endogenous prostaglandins (PGs). The aim of this study was to investigate adaptive cytoprotection under in vitro conditions in human gastric cells and to better delineate the role of endogenous PGs in this protective response. AGS cells (a human gastric carcinoma cell line) were characterized morphologically and subsequently used for all experiments. Sodium deoxycholate was used as both the mild irritant and the damaging agent, and cell injury was quantified using both a commercial viability/cytotoxicity kit as well as transepithelial permeability studies. Finally, endogenous PG synthesis in response to varying concentrations of deoxycholate was determined. AGS cells were determined to be morphologically similar to gastric mucous cells. Pretreatment of cells with low-dose deoxycholate significantly attenuated injury upon subsequent exposure to damaging concentrations of deoxycholate, and this protection was determined to be dependent upon both concentration and duration of mild irritant exposure. Preincubation of AGS cells with indomethacin reversed protection induced by mild irritant pretreatment and also significantly increased cellular susceptibility to injury. Results of the permeability studies closely paralleled those assessing cell mortality. While deoxycholate exposure increased PG synthesis, the concentrations required were much higher than those needed to initiate protection. Adaptive cytoprotection exists in AGS cells under in vitro conditions independent of intact blood flow, neural innervation, or circulating humoral mediators. While this protection is reversed by indomethacin, it appears that this reversal results from increased cellular injury secondary to diminished basal PGs, rather than inhibition of endogenous PG synthesis.

Cyclooxygenase inhibition attenuates cholecystokinin-induced gastroprotection

Cholecystokinin prevents gastric injury by an unknown mechanism. This study was conducted in conscious, fasted female rats in order to assess the role of endogenous prostaglandins as a potential protective mechanism for cholecystokinin-induced gastroprotection. Intravenous administration of cholecystokinin (0.05-5 nmol/kg) dose-dependently reduced macroscopic injury to the glandular portion of the stomach caused by 1 ml of orally administered acidified ethanol (150 mM hydrochloric acid-50% ethanol), an effect corroborated by histologic analysis. In time course studies, this protective action occurred as early as 10 min following cholecystokinin injection (5 nmol/kg intravenously), but was absent at 1 hr. Cyclooxygenase inhibition with either indomethacin (5 mg/kg intraperitoneally) or aspirin (100 mg/kg intraperitoneally) resulted in a partial reversal in cholecystokinin-induced gastroprotection, effects that were similar in magnitude. However, while indomethacin reduced gastric mucosal prostaglandin synthesis (enzyme-linked immunoassay) by 60%, aspirin almost totally abolished prostaglandin synthesis (95% reduction). Cholecystokinin (5 nmol/kg intravenously) did not significantly enhance gastric mucosal prostaglandin synthesis in the absence of cyclooxygenase inhibition. These data indicate that cholecystokinin requires the presence of endogenous prostaglandins in order to fully exert its gastroprotective actions. However, release of endogenous prostaglandins does not entirely explain the protective response, and additional factors likely participate in this action.

Early hypotension worsens neurological outcome in pediatric patients with moderately severe head trauma

PURPOSE

The objective of this study was to determine the morbidity associated with hypotension in the resuscitative phase of pediatric head trauma.

METHODS

A retrospective review (1990 to 1995) was performed at a level-1 pediatric trauma facility. Inclusion criteria included a Glasgow coma score (GCS) of 6 to 8 and absence of penetrating trauma or bleeding disorders. The GCS was assigned using a postresuscitation examination by a neurosurgeon. Hypotension was defined as a blood pressure reading of less than the fifth percentile for age that lasted longer than 5 minutes. Episodes were monitored from the onset of injury through the first 24 hours of hospitalization. Glasgow outcome scale (GOS) was assigned based on a 3-month follow-up evaluation. Analysis of variance (ANOVA) and contingency table analysis were performed on all groups, and a P value of less than .05 was taken to represent statistical significance.

RESULTS

Seventy-two patients met inclusion criteria. They had a mean GCS of 7.2 and a mean age of 6 years; 97% survived. Early hypotension was associated with worse neurological outcome (GOS) and prolonged hospitalization. There was no significant correlation between GOS and age, gender, injury mechanism, associated injuries, or transport time.

CONCLUSIONS

These data suggest that maintaining adequate blood pressure during the early resuscitation of pediatric blunt head trauma patients may improve neurological outcome.

The role of cyclooxygenase-1 and cyclooxygenase-2 in lipopolysaccharide and interleukin-1 stimulated enterocyte prostanoid formation

Lipopolysaccharide is an inflammatory agent and interleukin-1 is a cytokine. Their pro-inflammatory effects may be mediated by prostanoids produced by inducible cyclooxygenase-2. The aim of this study was to determine the prostanoids produced by lipopolysaccharide and interleukin-1 stimulated enterocytes through the cyclooxygenase-1 and 2 pathways. Cultured enterocytes were stimulated with lipopolysaccharide or interleukin-1beta with and without cyclooxygenase inhibitors. Low concentrations of indomethacin and valerylsalicylic acid (VSA) were evaluated as cyclooxygenase-1 inhibitors and their effects compared with the effects of a specific cyclooxygenase-2 inhibitor, SC-58125. Prostaglandin E2, 6-keto prostaglandin F1alpha, prostaglandin D2 and leukotriene B4 levels were determined by radioimmunoassay. Immunoblot analysis using isoform-specific antibodies showed that the inducible cyclooxygenase enzyme (COX-2) was expressed by 4 h in LPS and IL-1beta treated cells while the constitutive COX-1 remained unaltered in its expression. Interleukin-1beta and lipopolysaccharide stimulated the formation of all prostanoids compared with untreated cells, but failed to stimulate leukotriene B4. Indomethacin at 20 microM concentration, and VSA inhibited lipopolysaccharide and interleukin 1beta stimulated prostaglandin E2, but not 6-keto prostaglandin F1alpha formation. SC-58125 inhibited lipopolysaccharide and interleukin-1beta stimulated 6-keto prostaglandin F1alpha but not prostaglandin E2 release. The specific cyclooxygenase-2 inhibitor also inhibited lipopolysaccharide produced prostaglandin D2 but not interleukin-1beta stimulated prostaglandin D2. While SC-58125 inhibited basal 6-keto prostaglandin-F1alpha formation it significantly increased basal prostaglandin E2 and prostaglandin D2 formation. As SC-58125 inhibited lipopolysaccharide and interleukin-1beta induced 6-keto prostaglandin F1alpha production but not prostaglandin E2 production, it suggests that these agents stimulate prostacyclin production through a cyclooxygenase-2 mediated mechanism and prostaglandin E2 production occurs through a cyclooxygenase-1 mediated mechanism. Prostaglandin D2 production appeared to be variably produced by cyclooxygenase-1 or cyclooxygenase-2, depending on the stimulus.

Glutamate modulation of dopamine measured in vivo with positron emission tomography (PET) and 11C-raclopride in normal human subjects

Subanesthetic doses of the noncompetitive N-methyl-D-aspartate (NMDA) antagonist ketamine exacerbate psychosis in schizophrenic patients, and ketamine has significant abuse liability. These observations indicate that a secondary effect of ketamine may be to increase dopamine concentrations. The present study was undertaken using positron emission tomography (PET) and the dopamine (D2) radiotracer 11C-raclopride to determine whether ketamine would decrease D2 receptor availability, indicative of an increase in dopamine concentrations. Two scans were performed in seven male control subjects before and after administration of ketamine (0.5 mg/kg, i.v. infused over 20 min). Ketamine significantly increased cortisol levels and decreased dopamine receptor availability in the striatum (specific binding), but not in the cerebellum (nonspecific binding). In addition, the cerebellar binding subtracted from the striatal binding (to account for changes in nonspecific binding) was significantly decreased after ketamine administration. These results provide in vivo evidence for the ability of ketamine to increase striatal dopamine concentrations, consistent with the role of the NMDA receptor in modulating dopamine function.

Protection against ethanol injury by prostaglandin in a human intestinal cell line: role of microtubules

Prostaglandins have been shown to protect the gastrointestinal (GI) epithelium from injury induced by various luminal insults independent of their known acid-inhibitory effects, a process termed "cytoprotection." The mechanism of this protective action remains unknown. The present investigation determined the role of microtubules (a major cytoskeletal component) in GI injury induced by ethanol (EtOH) and its prevention by 16,16-dimethylprostaglandin E2 (dmPGE2) using cells from a human colonic cell line known as Caco-2 cells. These cells were preincubated in Eagle's minimum essential medium with and without dmPGE2 (2.6 microM) for 15 min and subsequently incubated in media containing 1, 2.5, 5, 7.5, and 10% EtOH. The effects on cell viability and tubulin (the major protein backbone of microtubules) were then determined. EtOH concentrations > or = 2.5% extensively disrupted the microtubules as demonstrated by fragmentation, kinking, and perturbation of the microtubule organizer center. EtOH treatment also led to a significant decrease in the S2 (polymerized) fraction and an increase in the S1 (monomeric) pool of tubulin. Concomitant with these effects were marked decreases in cellular viability. DmPGE2 pretreatment abolished the disruption of microtubules, significantly increased the S2 fraction of tubulin, and increased cellular viability in cultures exposed to EtOH. Furthermore, pretreatment with colchicine, an inhibitor of microtubule assembly, prevented the cytoprotective action of dmPGE2. Taxol, a microtubule stabilizing agent, mimicked the effects of dmPGE2 by also enhancing microtubule integrity and increasing cellular viability in cells exposed to EtOH. Our data indicate that organization and stabilization of microtubules may play an essential role in the mechanism of prostaglandin-induced protection.

The accuracy of the CAGE, the Brief Michigan Alcoholism Screening Test, and the Alcohol Use Disorders Identification Test in screening trauma center patients for alcoholism

OBJECTIVE

To evaluate the accuracy of questionnaire screening instruments to identify lifetime alcohol dependence among trauma center patients.

METHODS

The study was conducted at a Level I trauma center between September 1994 and November 1996. Patients meeting eligibility requirements (> or = 18 years old, admission from injury scene, > or = 2 days of hospitalization, intact cognition) were evaluated for alcohol abuse and dependence. Screening instruments consisted of the CAGE, the Brief Michigan Alcoholism Screening Test, and the Alcohol Use Disorders Identification Test. Screening results were compared with lifetime alcohol dependence diagnoses made using the in-depth Psychoactive Substance Use Disorders section of the Structured Clinical Interview. Accuracy was quantified as sensitivity, specificity, positive/negative predictive values, and receiver operating characteristic curves (used to calculate area under the curve).

RESULTS

Of the 1,118 patients studied, lifetime alcohol dependence was diagnosed by Structured Clinical Interview in 397 (35.5%), and abuse was diagnosed in 90 (8.1%) others. The CAGE was the best predictor of lifetime alcohol dependence, i.e., had the largest area under the curve (93%) and the highest sensitivity (84%), specificity (90%), positive predictive value (82%), and negative predictive value (91%). Among patients testing positive for alcohol, 63% had a lifetime alcohol dependence diagnosis.

CONCLUSION

The CAGE is an efficient screening test to detect alcohol dependence in trauma center populations. It should be used in combination with alcohol testing to identify patients at risk of alcohol use problems.

Genetic specificity of stress-induced anemia in rats

There is a genetic difference in rat hemoglobin (Hb) beta-chain structure, with alternate alleles, A and B, at a single locus. This study was designed to find out whether marrow sensitivity due to gamma exposure and experimentally induced anemia in age-matched adult rats is entirely strain specific or is a combination of both strain and Hb genotype. Eight strains of inbred and outbred rats comprising AA and BB types were examined. The data indicate that there is a relationship between marrow sensitivity and Hb genotypes in response to erythropoietic stress caused by three techniques.

Alcoholism at the time of injury among trauma center patients: vehicular crash victims compared with other patients

A structured in-depth interview employing standardized criteria was used to determine the prevalence of lifetime and current alcohol dependence (alcoholism) in unselected consecutive patients admitted to a regional Level I trauma center. Of 629 patients, 157 (25.0%) were current alcoholics at the time of injury. An additional 87 (13.8%) were diagnosed as lifetime non-current alcoholics. There was no significant difference in the rates of current alcohol dependence among patients injured in vehicular crashes (23.5%), other unintentional trauma victims (29.3%), and those injured as a result of violence (24.6%). Of BAC+ (blood alcohol concentration positive) patients, 54.5% were current alcoholics. However, 14.4% of alcohol-negative patients were also diagnosed as alcohol dependent.

Investigation of Polymer Brushes and Adsorbed Layers under Shear

Neutron reflectometry was used to investigate the density profiles of polymer brushes and an adsorbed polymer layer under shear. The brushes consisted of end-functionalized deuterated polystyrene. The adsorbed polymer was a random copolymer of deuterated styrene and 4-vinylpyridine. The brush and the adsorbed layer were sheared by the flowing of solvents over the polymer, with a maximum shear rate of 104s−1. Density profiles of the brush and the layer were determined before, during and after shear. The shear had no observable effect on the polymer profiles in any of the experiments. We discuss these results in the context of other experiments and a recent theory.

The role of bathtub seats and rings in infant drowning deaths

OBJECTIVE

To describe deaths due to drowning that involve the use of an infant bathtub seat or ring.

DESIGN

Case series, cases reported to the US Consumer Product Safety Commission data systems. Setting. United States, 1983-1995.

MAIN OUTCOME MEASURES

Death in which an infant bathtub seat or ring was in use at the time of death and the primary cause of death was drowning.

RESULTS

Thirty-two drowning deaths involving bath seats/rings were identified and investigated by the Consumer Product Safety Commission over a 13-year period. The majority of deaths (84%) occurred from 1991-1995, with more than 50% occurring in the 2 most recent years. The victims' ages at the time of the incident ranged from 5 to 15 months with a mean and median age of 8 months. In more than 90% of incidents there was a reported lapse in adult supervision, with a mean reported lapse of 6 minutes and a median lapse of 4 minutes. Focus groups with parents found that while making bathing somewhat easier, bath seats/rings are useful for a relatively short time period, as the child rapidly outgrows the product. They also suggested that care givers are more likely to leave a child unattended in the tub if one of these products is in use.

CONCLUSION

Bath seats/rings are associated with an increasing number of reported infant drowning deaths. The use of such products may increase the risk of drowning among infants by increasing the likelihood that an infant will be left alone in the tub. However, in the absence of exposure data in a suitable comparison group it is difficult to assess the overall risk inherent in their use. Educational efforts reinforcing the need for continuous adult supervision of infants and children around all bodies of water should now also include a reminder that bath seats/rings are not safety items and are not a substitute for adult supervision. Infants and toddlers should never be left in the bathtub unsupervised, even for brief moments.

Protective action of gastrin-17 against alcohol-induced gastric injury in the rat: role in mucosal defense

Exogenous cholecystokinin (CCK) or exposure of the stomach to the mild irritant 25% ethanol can prevent gastric injury. Ingestion of ethanol also elicits the release of CCK as well as gastrin, which is structurally similar to CCK. This study was undertaken in conscious rats to examine the gastroprotective actions of gastrin and to assess the effect of CCK-gastrin receptor blockade on adaptive cytoprotection with ethanol as the mild irritant. Intravenous (1-25 pmol/kg) administration of gastrin-17 dose dependently increased gastric mucosal blood flow (laser Doppler) and reduced gastric injury caused by 1 ml of orally administered acidified ethanol (150 mM HCl-50% ethanol). Similar gastroprotection was achieved with the gastrin secretagogue 5% peptone (1 ml orogastrically). The gastroprotective capabilities of gastrin-17 were attenuated by the type B CCK (gastrin) receptor antagonist L-365,260 (12.5-25 mg/kg i.p.) and by capsaicin desensitization (125 mg/kg s.c.). CCK octapeptide (5 nmol/kg i.v.)-induced protection was reversed by the type A CCK receptor antagonist MK-329 (1 mg/kg i.p.). Neither receptor antagonist, alone or in combination, reversed the protective effects of the mild irritant 25% ethanol (1 ml orogastrically). Thus, whereas gastrin may play a role in gastric mucosal defense, neither CCK nor gastrin appears to participate in the phenomenon of adaptive cytoprotection.

Alternative approaches to analytical designs in occupational injury epidemiology

In this paper, we discuss the theoretical framework upon which observational studies of occupational injuries are based. Following a general description of how causal effects are estimated, the challenges faced by researchers working in this area are outlined, with an emphasis on case-control studies. These challenges include defining the at-risk period for workers whose tasks change over time and whose hazard period may be very brief, evaluating the underreporting of both exposures and injuries, and considering the effects of multiple injuries per individual on study design and data analysis. We review both the theoretical and practical considerations in the design and conduct of traditional case-control studies, based on the collection of individual level data, as well as other approaches, such as using information culled from administrative and descriptive databases, and case-control studies in which the plant or work site is the unit of analysis. The case-crossover design is also reviewed and its utility for reducing confounding due to differences between individuals by self-matching is highlighted. While this design has not yet been applied to the work setting, its potential for increasing our understanding of the causes of acute-onset occupational injuries seems promising. Finally, a variety of hybrid designs are discussed, including combinations of case-control, case-crossover, and cohort designs.

Three perspectives on work-related injury surveillance systems

This paper reviews surveillance approaches for occupational injuries and evaluates three emerging methodologies for the enhancement of work-related injury surveillance: (1) narrative data analysis, (2) data set linkage, and (3) comprehensive company-wide surveillance systems. All three methods are the result of new applications of computer hardware and software that have apparent strengths and limitations. A major strength is the improved description of work exposures and related injuries leading to better understanding of injury etiology. This understanding, however, is limited by the data quality and completeness entered on records at the time of the injury. We recommend (1) more widespread inclusion of narrative text in databases, analyses of which can be a valuable supplement to injury coded data; (2) the increased use of data set linkage studies to combine injury and work-history data; and (3) the development of comprehensive company-wide surveillance systems to expedite the use of epidemiologic data for occupational injury prevention activities. Further development of these methods and others is encouraged, especially in light of technological advancements in data capture, analysis and presentation. Only through such efforts can we best apply epidemiologic principles to preventing injuries in the workplace.

Failure of dietary bentonite clay, Silent Herder mineral supplement, or parenteral Banamine to alleviate locoweed toxicosis in rats

To evaluate treatments purportedly beneficial for livestock grazing locoweeds (LW), growing rats were fed diets containing 10 or 20% whole-plant Oxytropis sericea (LW) with and without Silent Herder mineral mix (1.5% of diet) or bentonite clay (1.5% of diet). Pregnant female rats fed 10% LW were treated i.m. with Banamine (a prostaglandins suppressor) or saline. The LW contained swainsonine (430 micrograms/g DM) and elicited toxicosis within 10 d at intake of 2 mg/kg BW. In Trial 1, 96 immature male Sprague-Dawley rats (BW approximately 100 g) were fed commercial rat feed (CRF) with and without LW, as follows: 100% CRF, free choice; 100% CRF, restricted intake to equal average intake of rats consuming 10 and 20% LW; 90% CRF+10% LW free choice; and 80% CRF+20% LW free choice. Diets with LW contained either no supplement or supplemental mineral mixture (Silent Herder, 1.5% of diet) or added bentonite clay (1.5% of diet). Twelve rats received each of eight dietary regimens through 28 d. Locoweed depressed (P < .05) feed intake and BW gain, increased (P < .05) relative size of liver, kidneys, heart, spleen, and testes, and altered blood serum components (P < .05) indicating toxicosis. Dietary provision of Silent Herder or bentonite failed to benefit rats that ingested approximately 4 or 8 mg of swainsonine/kg BW daily through 28 d. In Trial 2, 68 young adult female Sprague-Dawley rats (approximately 230 g BW) were mated and directly assigned to three diets (100% CRF, free choice, 100% CRF, intake restricted slightly below average intake of diet by rats consuming LW, or 90% CRF+10% LW free choice) and two treatments (i.m. saline or i.m. Banamine at .25 mg/kg BW daily for 10 d) in a 3 x 2 factorial arrangement. Approximately half (31 of 68) of the impregnated rats were killed at d 10, when Banamine was discontinued, but diets were continued until the remaining females gave birth. Ingested LW provided approximately 2 mg swainsonine/kg BW daily and elicited toxicosis in 10 d, but LW failed to affect numbers of live concepti at d 10 (P > .5) or numbers of offspring at parturition (P > .10). Banamine did not alleviate LW toxicosis of dams (P > .10). Provision of Silent Herder or bentonite in the diet or Banamine i.m. had no benefit for rats fed toxic locoweed.

Psychoactive substance use disorders among seriously injured trauma center patients

OBJECTIVE

To assess the prevalence of psychoactive substance use disorders (PSUDs) among a large, unselected group of seriously injured trauma center patients, using a standardized diagnostic interview and criteria.

DESIGN

Prevalence study.

SETTING

A level I regional trauma center.

PATIENTS

Trauma center patients fulfilling the following criteria were eligible subjects: aged 18 years or older, admission from injury scene, length of stay of 2 days or longer, and intact cognition.

OUTCOME MEASURES

The PSUDs were diagnosed using the Structured Clinical Interview (SCID) for the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R) and were categorized as abuse or dependence and past or current (within past 6 months). The SCID results were analyzed with respect to demographic factors, injury type, and blood alcohol concentration and urine toxicology results, using chi2 and logistic regression techniques.

RESULTS

Of the 1220 patients approached for study, 1118 (91.6%) consented. More than half (54.2%) had a diagnosis of a PSUD in their lifetime. Approximately 90% of alcohol and other drug use diagnoses were for dependence and more than 62% were current. Overall, 24.1% of patients were currently alcohol dependent (men, 27.7%; women, 14.7%; P<.001), and 17.7% were currently dependent on other drugs (men, 20.2%; women, 11.2%; P<.001). Current alcohol dependence rates were not associated with race; rates of dependence on other drugs were higher among nonwhites and victims classified with intentional injuries. While 54.3% of blood alcohol-positive patients were currently alcohol dependent and 38.7% of patients with positive urine screening test results for drugs other than alcohol and nicotine were currently drug dependent, 11.7% of blood alcohol-negative and 3.9% of drug-negative patients, respectively, had current diagnoses of dependence on psychoactive substances.

CONCLUSIONS

A high percentage of seriously injured trauma center patients are at risk of having current PSUDs. Patients with positive toxicology screening test results and/or positive screening questionnaire responses should be referred for formal evaluation and treatment.

Expression of ethylene biosynthetic genes in Actinidia chinensis fruit

The fruit of Actinidia chinensis, a diploid relative of kiwifruit, showed an increased rate of ripening in response to the application of exogenous ethylene. Moreover, late in ripening the fruit produced a burst of ethylene biosynthesis. Thus ripening is climacteric, and there is a clear temporal separation of ethylene sensitivity and ethylene production. RNase protection assays were used to monitor transcript levels of ethylene biosynthetic genes during fruit development and ethylene-induced ripening. The application of exogenous ethylene correlated with increased transcript levels for three different S-adenosyl-L-methionine (SAM) synthetase genes and for the 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene family. Transcription of an ACC synthase gene was not affected by exogenous ethylene. However, ACC synthase transcript levels increased during subsequent ethylene production by the fruit, consistent with this being the control step for the onset of climacteric ethylene production. ACC oxidase transcripts increased significantly both prior to and during climacteric ethylene production, while only one of the three SAM synthetase transcripts was induced during the late ethylene burst. We propose that the regulation of SAM synthetase transcripts by ethylene may occur as part of the methionine salvage pathway.