Serotonergic modulation of dopamine measured with [11C]raclopride and PET in normal human subjects

OBJECTIVE

This study was undertaken to measure serotonergic modulation of dopamine in vivo by using positron emission tomography (PET), a radiotracer for the striatal dopamine D2 receptor ([11C]raclopride), and a pharmacologic challenge of the serotonin system (d,l-fenfluramine).

METHOD

Two PET studies using [11C]raclopride were performed in 11 normal male subjects before administration of the serotonin-releasing agent and reuptake inhibitor fenfluramine (60 mg p.o.) and 3 hours afterward. A graphical analysis method was used with the [11C]raclopride data to derive the distribution volume of D2 receptors. Plasma levels of fenfluramine, norfenfluramine, homovanillic acid (HVA), cortisol, and prolactin were determined.

RESULTS

Levels of fenfluramine and prolactin were elevated 2 hours after fenfluramine administration and remained significantly elevated during the second scan, while levels of HVA and cortisol were not altered significantly during the time of scanning. A significant decrease in the specific binding (striatum) and the nonspecific binding subtracted from the specific binding (striatum minus cerebellum) of [11C]raclopride was observed. The rate of metabolism of [11C]raclopride and the nonspecific binding (cerebellum) were not significantly altered by the fenfluramine intervention.

CONCLUSIONS

The observed decrease in [11C]raclopride binding is consistent with an increase in dopamine concentrations and with the ability of serotonin to stimulate dopamine activity. The ability to measure serotonergic modulation of dopamine in vivo may have implications for the study of etiologic and therapeutic mechanisms in schizophrenia, major depressive disorder, obsessive-compulsive disorder, and substance abuse.

Field Screening of Commercial and Experimental Soybean Cultivars for Their Reaction to Macrophomina phaseolina

From 1992 to 1994, 24 soybean cultivars, ranging in maturity from early group III to late group IV, were assessed in the field for resistance and susceptibility to Macrophomina phaseolina. Cultivars were placed into four relative maturity classes-3.2 to 3.4; 3.5 to 3.8; 3.9 to 4.0; and 4.3 to 4.9-with six cultivars per class. Twelve cultivars were resistant and 12 were susceptible to Heterodera glycines, the soybean cyst nematode. Cultivars were planted on two dates (early May and early June) to assess the effect of environment on yield and lower stem and taproot colonization by the fungus at growth stage R7. Based on seed yields and the levels of lower stem and taproot colonization by M. phaseolina, four cultivars-Asgrow 4715, DeltaPineland 3478, Hamilton, and Jackson II-were rated moderately resistant to M. phaseolina. Seed yields and M. phaseolina levels in host tissues were affected by planting date, relative maturity class, H. glycines response, and the environmental conditions that prevailed over the 3 years of the study. However, in general, the environmental, agronomic, and host genetic factors present in these experiments did not affect the individual cultivar/pathogen interaction. Quantification of microsclerotial propagules in lower stem and taproot tissues at growth stage R7 was a reliable, but time-consuming, method to measure the degree of host compatibility between soybean cultivars and M. phaseolina.

Alcohol and injury severity: reappraisal of the continuing controversy

It is well recognized that alcohol increases the risk of injury. It is controversial, however, whether alcohol also has an effect on the degree and outcome of injury after controlling for the severity of impact. This review examines the evidence from experimental studies in animals regarding the potentiating effects of alcohol on trauma, and the methodologic issues that may have contributed to the contradictory findings of clinical and epidemiologic studies. Most experimental studies indicate that alcohol can adversely affect the degree and outcome of injury. In controlled laboratory conditions, alcohol is found to reduce cardiac output, to increase the susceptibility to hemorrhagic shock, and to increase the pulmonary vascular resistance after standardized experimental injuries. However, it is difficult to extrapolate these findings to humans, partly because the interactive effects of chronic and acute alcohol use on trauma are rarely considered in experimental studies. The conflicting results in studies involving trauma patients are due in part to the differences in study design, particularly selection of study populations, and in measuring and controlling for kinetic forces on the body. Studies indicating that alcohol is associated with an increased risk of serious or fatal injury are usually based on data from emergency departments or police departments. The alcohol-injury severity relationship reported in these studies is attributable to a great extent to the effects of correlates of alcohol, such as speeding and not wearing seat belts, rather than the biological effects of alcohol. Studies indicating that alcohol is not associated with the degree and outcomes of injury are mostly those involving patients who were admitted to hospitals or trauma centers. Methodologic issues concerning the alcohol-injury severity controversy, including conceptual models and future research needs, are discussed.

Agricultural and horticultural chemical poisonings: mortality and morbidity in the United States

STUDY OBJECTIVE

To provide a comprehensive analysis of morbidity and mortality from poisoning by agricultural and horticultural chemicals in the United States.

METHODS

Descriptive analysis of national mortality data, National Hospital Discharge Survey data, and American Association of Poison Control Centers national data for 1985 through 1990.

RESULTS

There were 341 fatalities from agricultural and horticultural chemicals over the 6-year period, of which 64% were suicides, 28% were unintentional, and 8% were of undetermined intent. There were 25,418 hospitalizations; 78% were reported to be unintentional. Both deaths and hospitalizations occurred more frequently in males, and rates were higher in nonwhites than in whites. There were 338,170 poison exposures reported to poison centers for fungicides, herbicides, pesticides/insecticides, and rodenticides. Life-threatening manifestations or long-term sequelae occurred in 782 cases, and 97 deaths were reported. Pesticides and insecticides accounted for 72% of the poison center cases and 63% of the fatalities. Although they accounted for only 8% of poison exposures, herbicide deaths were disproportionately high (25%).

CONCLUSION

Poisonings with agricultural and horticultural chemicals are an important public health problem. Prevention efforts need to incorporate the fact that many serious cases, such as paraquat poisonings, are suicidal in nature.

The effect of trinitrobenzene sulfonic acid on gut-derived smooth muscle cell arachidonic acid metabolism: role of endogenous prostanoids

The contribution of smooth muscle cells as a potential source of eicosanoid production during inflammatory states remains to be elucidated. We investigated the effect of trinitrobenzene sulfonic acid (TNB), a known pro-inflammatory agent, on jejunal smooth muscle cell eicosanoid production. Human gut-derived smooth muscle cells (HISM) were incubated with TNB for 1 hour. Additionally, some cells were preincubated with either dimethylthiourea, or indomethacin for 1 hour before exposure to identical concentrations of TNB. Incubation with TNB led to significant increases in PGE₂ and 6-keto PGF-1_α release, but not leukotriene B₄ release; responses which were both inhibited by dimethylthiourea and indomethacin treatment. Our results suggest that gutderived smooth muscle cells may represent an important source of proinflammatory prostanoids but not leukotrienes during inflammatory states of the intestine. The inhibition of prostanoid activity by thiourea may be mediated by suppression of cyclooxygenase activity in this cell line.

Pediatric injuries presenting to an emergency department in a developing country

PURPOSE

To describe the causes and outcomes of pediatric injuries using the emergency departments (ED) as a surveillance site.

METHOD

Prospective, 14-day surveys of all injuries were conducted in the EDs of the two national trauma referral hospitals of Trinidad and Tobago. Data on patient demographics, type, cause, and outcome of injuries were collected. The chi 2 test for significance was used for categorical variables.

RESULTS

Pediatric patients (< 20 years) accounted for 41.5% (714/1722) of injury visits. Of these, 62.6% were male and 17.4% were < four years old, 26.2% four to nine years, 31.1% 10 to 14 years, and 25.4% were 15 to 19 years old. Three patients (0.4%) died, 68.6% were discharged, and 31.0% admitted. Intentional injuries accounted for 13.9% of injuries. Of the intentional injuries, the assailant was significantly more likely to be known than not (P < 0.01). The most common causes of all injuries were: falls, 44.4%; blunt objects, 12.3%; sharp objects, 11.8%; motor vehicle (including pedestrians), 7.4%; poison, 3.6%; and burns, 1.7%. Injuries occurring in the home accounted for 46.2%; in school, 25.5%; sports/recreation, 11.1%; and at work, 4.5%. The most common injuries were: lacerations, 30.8%, contusions/abrasions, 26.7%, fractures, 18.8%; and sprains/dislocations, 9.4%.

CONCLUSION

Pediatric injuries are a significant cause of morbidity and mortality in this country, accounting for almost one third of injured patients. Because of the low frequency of pediatric injury deaths, ED surveillance may be a more effective means of identifying high risk groups and activities for injuries. Data from EDs may be useful in other developing countries to develop injury prevention programs.

Development of nursing documentation for use in the outpatient oncology setting

In response to the particular demands upon patients and nursing staff in the outpatient setting, and the identification of a need for nursing orientated documentation, a new nursing documentation system has been developed and implemented within an oncology day unit. The documentation is used by the nursing team engaged in the care of patients receiving outpatient chemotherapy treatment. The system consists of documents for the initial and ongoing assessment, planning, implementation and evaluation of nursing care. These include pretreatment patient self-assessment forms, flowsheets for the documentation of chemotherapy treatment and administration and a record for information and teaching given to patients and significant others. Referrals to other services and health care professionals are also documented. This tool is designed to ensure a high standard of nursing intervention and maximize quality of life in this group of patients. An audit is planned to evaluate the effectiveness of this tool and highlight any areas requiring improvement or modification. There are also plans to further develop this system for use in the inpatient and community setting.

Cholecystokinin-induced protection against gastric injury is independent of endogenous somatostatin

Cholecystokinin (CCK) prevents macroscopic injury to the stomach from luminal irritants by an unknown mechanism. The present study was undertaken in conscious rats to ascertain what role gastric mucosal blood flow, sensory neurons, and endogenous somatostatin play in CCK-induced gastric protection. Subcutaneous administration of CCK (10-100 micrograms/kg) significantly reduced macroscopic injury to the acid-secreting portion of the stomach caused by 1 ml of orally administered acidified ethanol (150 mM HCl, 50% ethanol) and augmented gastric mucosal blood flow (fluorescent microspheres) in a dose-dependent fashion. However, although the protective response to CCK (100 micrograms/kg) was still present at 2 h, the blood flow response had returned to baseline by 45 min. Ablation of capsaicin-sensitive afferent neurons with capsaicin (125 mg/kg sc) did not negate CCK-induced protection. Pretreatment with exogenous somatostatin (1 pmol-1 nmol/kg sc) failed to prevent the damaging effects of acidified ethanol to gastric mucosa. Immunoneutralization of endogenous somatostatin with somatostatin monoclonal antibody (2 mg ip) did not reverse the protective actions of CCK. Thus the data suggest that although CCK may prepare the gastric mucosa to withstand a damaging insult by augmenting gastric mucosal blood flow, its protective mechanism is independent of intact sensory neurons and endogenous somatostatin.

The study of neurotransmitter interactions using positron emission tomography and functional coupling

Functional brain imaging with positron emission tomography (PET) has opened up new avenues for the investigation of possible functional disturbances related to psychiatric disease as well as pharmacodynamic assessment of drug treatment in vivo. Different strategies to study pharmacologic effects on the brain have been developed in recent years. The basic methods are to measure (a) blood flow or glucose metabolism, (b) parameters of specific receptor binding, or (c) neurotransmitter metabolism. Each of these can be performed either in a resting state or after perturbation with a pharmacologic challenge. Our group has developed a general strategy for investigating pharmacologic effects on brain function: (a) determining indirect drug-induced metabolic changes with fluorodeoxyglucose PET and (b) characterizing functional interactions of neurotransmitter systems by assaying drug-induced displacement of specific receptor ligands. These study designs reflect a paradigm shift where functional coupling of brain regions and interaction of different neurotransmitter systems are seen as the basis for a multitransmitter hypothesis of schizophrenia. In this view, any disturbance in the self-regulatory process is reflected in the loss of functional interaction between systems. An overview of recent studies and their possible clinical importance will be presented.

Decreased reproductive effects from snakeweed (Gutierrezia microcephala) in Sprague-Dawley rats with increased dietary snakeweed consumption

Sprague-Dawley rats have been used to study the pathogenesis and toxicokinetics of snakeweed (Gutierrezia microcephala and G sarothrae) toxicosis. Diets containing as little as 10% snakeweed (SW) will induce early embryonic toxicosis and abortion in Sprague-Dawley rats. The sc administration of safflower oil to inseminated female rats will provide protection/tolerance against SW embryotoxins. Two studies evaluated this embryotoxin protection. In the first study, an increase in daily consumption of SW resulted in increased embryo-fetal survival in the SW-containing diet+saline group from 0% in previous studies to 35%. In the second study, once again an increase in diet consumption was associated with 40% of the females in the SW-containing diet+saline group carrying litters to term.

Effects of lipopolysaccharide on intestinal injury; potential role of nitric oxide and lipid peroxidation

Nitric oxide can react with superoxide anion to form peroxynitrite. The resultant free radical can be rapidly protonated to yield even more toxic substances such as hydroxyl radical and nitric dioxide. The generation of either of these free radical species can promote lipid peroxidation and subsequent tissue injury if they are formed in excessive amounts. During sepsis, both nitric oxide synthesis and peroxynitrite production are substantially enhanced in a variety of tissues, effects which favor the development of lipid peroxidation. Consequently, this study was undertaken in conscious rats, to ascertain what effect lipopolysaccharide (LPS) has on inducible nitric oxide synthase expression in the small intestine and to determine whether this is associated with lipid peroxidation or morphologic injury. When examined by Western immunoblot analysis, significantly more inducible nitric oxide synthase immunoreactivity was detected in the ileum than in the jejunum 5 hr after treatment with intraperitoneal LPS (1 and 20 mg/kg). Further, using the thiobarbituric acid assay as an index of lipid peroxidation, it was demonstrated that significantly more thiobarbituric acid reactive substances were present in the ileal mucosa than in the jejunal mucosa after LPS (20 mg/kg) administration. However, LPS (20 mg/kg) resulted in morphologic damage to both segments of the intestinal epithelium. These data indicate that the gut is a target during sepsis and that regional differences exist within the small bowel with respect to induction of nitric oxide synthase and lipid peroxidation following LPS treatment. Thus, while induction of nitric oxide synthase during endotoxic shock may still represent a mechanism of local intestinal damage, it is not necessarily associated with enhanced lipid peroxidation.

Gastric injury induced by ethanol and ischemia-reperfusion in the rat. Differing roles for lipid peroxidation and oxygen radicals

This study determined the role that oxygen-derived free radicals played in the production of gastric injury in rats challenged orally with concentrated ethanol or subjected to vascular compromise. In the ethanol study, rats were pretreated with a variety of free radical scavengers or enzyme inhibitors prior to exposing the stomach to 100% ethanol. At sacrifice, the degree of macroscopic damage to the glandular gastric mucosa was quantified. In separate studies, the effects of ethanol on gastric mucosal levels of enaldehydes (malondialdehyde and 4-hydroxynonenal) were examined as an index of lipid peroxidation. Superoxide dismutase and catalase pretreatment were without benefit in reducing injury in our ethanol model, excluding potential contributory roles for the superoxide anion or hydrogen peroxide, respectively. Dimethyl sulfoxide and desferoxamine were likewise without protective capabilities, eliminating a role for the hydroxyl radical. Allopurinol, a xanthine oxidase inhibitor, provided no protection under acute conditions, even though partial protection was noted when administered chronically. Further, enaldehyde levels were not increased over control levels in alcohol-exposed mucosa, indicating no enhanced lipid peroxide formation. In contrast, in animals in which ischemia to the stomach was induced followed by reperfusion, marked gastric injury was observed in combination with enhanced enaldehyde levels. Prevention of enaldehyde formation by a 21-aminosteroid concomitantly prevented injury induced by ischemia-reperfusion. These findings support the conclusion that ischemia-reperfusion injury to the stomach is an oxygen-derived free radical process whereas ethanol-induced injury clearly involved some other process. Although allopurinal was partially protective against ethanol damage when administered chronically, observations in other models of injury suggest that this action is independent of its inhibitory effect on xanthine oxidase.

Hepatotumorigenicity and peroxisome proliferation induced by the hypolipidemic CI-924 in a two-year study in male and female B6C3F1 mice

The hepatic tumorigenicity of CI-924 (5,5'-(1,1'-biphenyl)-2,5-diylbis(oxy)(2,2-dimethylpentanoic acid)), a hypolipidemic agent, was evaluated in 50 B6C3F1 mice/sex/dose given drug in the diet at 0, 5, 25, and 75 mg/kg/day for 2 yr. Peroxisomal and drugmetabolizing enzyme determinations, as well as ultrastructural evaluations, were conducted in subsets of these same groups, because drugs of this class cause peroxisome proliferation and hepatic tumors in rodents. CI-924 elicited dose-dependent increases in the incidence of hepatocellular adenomas and carcinomas in both sexes that were statistically significant at 75 mg/kg. Stereologic evaluation revealed significant increases in hepatocellular peroxisome volume ratio, due to increased numbers of peroxisomes, in females at all doses and males at 75 mg/kg. Peroxisomal enzyme activity measurements revealed no change in catalase, but dose-dependent increases in carnitine acetyltransferase and cyanide-insensitive beta-oxidation in both sexes. Peroxisome proliferation, determined biochemically or ultrastructurally, was twice as great in females compared to males. Total cytochrome P-450 was increased in both sexes given 75 mg/kg. There were dose-dependent decreases in glutathione S-transferase in males and increased glutathione peroxidase in both sexes at 25 and 75 mg/kg. In conclusion, this study demonstrated that while CI-924 induced hepatic tumors in male and female B6C3F1 mice the associated peroxisome proliferation, while moderate in females, was only weak in the males after 2 yr of exposure.

Feasibility of using a swine portal vein containing a metallic stent for creating a portacaval shunt

RATIONALE AND OBJECTIVES

We evaluated the feasibility of using a metallic stented portal vein as a conduit for portacaval shunt in pigs.

METHODS

A metallic self-expanding stent was placed in the portal vein of five pigs under combined ultrasound and fluoroscopic guidance via a percutaneous transhepatic approach. After 6 weeks, a portacaval shunt was performed using the stented portal vein as a conduit. A single angiogram followed immediately by sacrifice and histologic examination was performed on each pig at a varying time interval postshunt.

RESULTS

One pig died 3 days after the shunt procedure because of a presumed surgical technical failure and a consequent thrombosed portal vein. Angiographic patency of the portacaval shunt was confirmed in the four remaining pigs. Postmortem histologic evaluation showed more complete endothelialization and subintimal organization in the more chronic stents. Thrombus occurred only in the stent of the pig that died. There was no significant luminal obstruction in the other four stents.

CONCLUSION

Our results suggest that a stented portal vein can be used successfully as a conduit for portacaval shunt in pigs.

Gastric injury and protection against alcohol and acid: influence of perturbations in glutathione metabolism

This study assessed the role that inhibition of glutathione (GSH) synthesis and decreased GSH peroxidase (GPX) activity in the rat played in modulating gastric injury induced by ethanol and acid and its prevention by 16,16-dimethyl PGE2 (dmPGE2) and the mild irritant, 25% ethanol. Although numerous studies have proposed that GSH may be important in maintaining gastric mucosal defense, the exact role of this antioxidant in protecting the stomach from injury remains undefined. The present study addressed this consideration by blocking the synthesis of GSH and altering the major pathway by which it exhibits its antioxidant activity and determining the effect of these perturbations on gastric injury and protection. Four to six rats were used for each experimental group. GSH synthesis was blocked by the potent and specific inhibitor L-buthionine sulfoximine (BSO), 2 or 6 mmole/kg intraperitoneally. The activity of the major form of GPX, which is selenium dependent and utilizes GSH as a substrate to detoxify hydrogen peroxide and other hydroperoxides, was inhibited by placing animals on a selenium-deficient diet for 6 weeks. Gastric damage was induced by 100% ethanol, 50% ethanol in 150 mM HCl, and 0.75 M HCl. Prevention of such injury was accomplished with oral pretreatment using 25% ethanol or dmPGE2 (5 microgram/kg). The damaging effects of 100% ethanol, 50% ethanol/150 mM HCl, or 0.75% M HCl were not adversely affected by BSO pretreatment even though GSH synthesis was inhibited by as much as 80%. Similarly, inhibition of GPX activity by 58% in adult rats and 98% in weanling rats failed to potentiate the damaging effect of 100% ethanol. Furthermore, with both perturbations in GSH metabolism, the protective action of dmPGE2 and 25% ethanol was maintained. Our results indicate that profound alterations in gastric GSH metabolism by themselves do not aggrevate the injurious effects of ethanol or acid, nor do they prevent the protective action of a prostaglandin or mild irritant.

Effects of formic acid hydrolysis on the quantitative analysis of radiation-induced DNA base damage products assayed by gas chromatography/mass spectrometry

Gas chromatography/mass spectrometry (GC/MS-SIM) is an excellent technique for performing both qualitative and quantitative analysis of DNA base damage products that are formed by exposure to ionizing radiation or by the interaction of intracellular DNA with activated oxygen species. This technique commonly uses a hot formic acid hydrolysis step to degrade the DNA to individual free bases. However, due to the harsh nature of this degradation procedure, the quantitation of DNA base damage products may be adversely affected. Consequently, we examined the effects of various formic acid hydrolysis procedures on the quantitation of a number of DNA base damage products and identified several factors that can influence this quantitation. These factors included (1) the inherent acid stabilities of both the lesions and the internal standards; (2) the hydrolysis temperature; (3) the source and grade of the formic acid; and (4) the sample mass during hydrolysis. Our data also suggested that the N,O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) derivatization efficiency can be adversely affected, presumably by trace contaminants either in the formic acid or from the acid activated surface of the glass derivatization vials. Where adverse effects were noted, modifications were explored in an attempt to improve the quantitation of these DNA lesions. Although experimental steps could be taken to minimize the influence of these factors on the quantitation of some base damage products, no single procedure solved the quantitation problem for all base lesions. However, a significant improvement in the quantitation was achieved if the relative molecular response factor (RMRF) values for these lesions were generated with authentic DNA base damage products that had been treated exactly like the experimental samples.

Effects on reproduction in female offspring from Sprague-Dawley rats fed 10% snakeweed (Gutierrezia microcephala) throughout pregnancy and concurrent treatment with safflower oil

Previous studies determined that safflower oil administration provided protection against the embryotoxicity seen following ingestion of 10% snakeweed (Gutierrezia microcephala) throughout pregnancy. Sixty-two young primiparous female rats born in those studies were paired with adult male Sprague-Dawley rats. After 4 d they were removed and carried their litters to term. Observations were made of the presence and extent of reproductive effects attributable to the 10% snakeweed exposure and differences in fecundity that were attributable to dosing with safflower oil or normal saline during the snakeweed exposure. Of the 62 rats, 50 carried litters to term and approximated the reproductive efficiency of normal primiparous Sprague-Dawley rats. There was no significant difference between the fecundity of females born to rats fed the 10% snakeweed and dosed with safflower oil, those born of rats fed snakeweed dosed with normal saline, or those fed a snakeweed-free diet and dosed with normal saline. Regardless of the diet or treatment administered, dams carrying their litters to parturition gave birth to healthy, normo-reproductive offspring. While the toxic principles in Gutierrezia species plants may act as estrogenic or anti-estrogenic compounds, they did not impair fertility in the female offspring of dosed rats.

Prevalence and age-specific incidence of burns in Ghanaian children

The incidence of burns in developing countries is not precisely known due to unavailability or incompleteness of death registration and disease reporting. In this study, we determined prevalence and age-specific incidence of burns in children 0-5 years in the Ashanti region of Ghana using burn scars as proxy. We used a community-based, multi-site survey to identify children who had scars as evidence of previous burns. A scar prevalence of 6 per cent was found. No sex differences were found. However, significant differences were found among age groups, with children aged 18-23 months having the highest incidence (57.4 per 1000 person-years). There was evidence of focal occurrence of childhood burns in certain districts, and a higher prevalence in rural areas. We conclude that childhood burns are a significant health problem in Ghana, especially among rural residents and the very young, and recommend that interventions be developed to control them.

Epidemiology and practice of emergency medicine in a developing country

STUDY OBJECTIVE

To analyze the emergency medicine system in a developing country and identify areas of need and potential collaboration.

DESIGN

Convenience sample surveys of all emergency visits over a 2-week period, hospital admission and health department statistics, and interviews with government officials, health providers, and EMS managers.

SETTING

Port of Spain General Hospital, Trinidad and Tobago.

RESULTS

The ED has more than 100,000 visits per year. No records are kept. No physician in this study had emergency medicine training; only one had completed any residency. The survey included 3,710 patients: 40.5% were admitted, and .3% died. Injuries accounted for 41.6% of all visits, asthma 7.8%. The mean time elapsed before a patient was seen was .5 hour; mean time to discharge, 1.9 hours. In only 9% of patients were laboratory tests performed. Prehospital providers had limited equipment and training.

CONCLUSION

The ED and prehospital systems provide high-volume and often high-acuteness care. Barriers to improved care include limited specialized training and lack of medical records.

Improving the E coding of hospitalizations for injury: do hospital records contain adequate documentation?

OBJECTIVES

Incomplete external cause of injury (E) coding limits the usefulness of hospital discharge data sets for injury surveillance and research. Hospital medical records were examined to determine whether they contained adequate cause of injury documentation to allow for more complete E coding of injury discharges.

METHODS

Medical records for a sample of discharges involving a principal diagnosis of injury from the Uniform Hospital Discharge Data Set for Rhode Island were selected. We assigned E codes to these discharges and compared our E codes with those of the discharge data set.

RESULTS

Documentation of cause of injury in the medical records was sufficient to allow assignment of a specific E code to 70% of the injuries for which no E codes or vague E codes were submitted on the Uniform Hospital Discharge Data Set. It was estimated that specific cause of injury documentation is available in the medical records of 80% of all injury discharges in Rhode Island; for approximately 90%, an E code describing at least the broad cause of injury could be assigned.

CONCLUSIONS

Rates of E coding can be substantially increased by making better use of existing documentation in medical records.

Relative rates of fracture of the hip in the United States. Geographic, sex, and age variations

We studied the Medicare data from 1984 through 1987 for 687,850 fractures of the hip that had occurred in the United States. Our purpose was to determine the geographic, sex-specific, and age-interval variations in the relative risk of fracture of the hip in elderly white individuals. The rates of cervical, trochanteric, and subtrochanteric fracture, and the over-all rate of fracture at any of the three levels, increased with age, were greater for women than for men, and were higher in the Southern part of the country. However, there were regional, sex, and age variations. The ratio of cervical to trochanteric fractures was significantly higher in the East South Central region and lower in the Middle Atlantic and New England regions (p < 0.05). These were the same areas with the highest and lowest over-all rates, respectively, of fracture of the hip. The ratio of cervical to trochanteric fractures decreased from 1.52 in women who were sixty-five to sixty-nine years old to 0.81 in women who were at least eighty-five years old, but it stayed at approximately 1.00 for the corresponding age-groups of men. The ratio of fracture of the hip in women to fracture of the hip in men varied depending on the level of the fracture.

Protective effect of a 21-aminosteroid against hemorrhage-induced ischemia-reperfusion injury in the rat stomach: role of lipid peroxidation

We investigated the role that lipid peroxidation plays in a hemorrhage-induced ischemia-reperfusion model of gastric injury. Rats were pretreated with an inhibitor of this process, a 21-aminosteroid (U-74389G, 10 mg/kg), or an appropriate control solution intravenously 15 min prior to 20 min of ischemia, followed by 20 min of reperfusion. Results indicated that U-74389G pretreatment significantly attenuated gastric damage compared with corresponding control animals (19.8 vs. 176.8 mm2, p < .001). Enaldehyde levels (picomoles/mg protein), a biochemical index of lipid peroxidation, paralleled these injury findings (12 vs 960, p < .001). Histologically, U-74389G pretreatment almost completely prevented gastric injury compared to control stomachs. Additional studies revealed that lipid peroxidation preceded the formation of gastric damage, and injury occurred predominantly during reperfusion, because animals subjected to ischemia alone without reperfusion failed to develop appreciable injury or enhanced enaldehyde formation. Further, if U-74389G was given intravenously after ischemia, but prior to reperfusion, gastric injury and enaldehyde formation were similarly attenuated. Our findings are consistent with the hypothesis that lipid peroxidation likely plays an important role in hemorrhage-induced ischemia-reperfusion injury to the stomach.

Risk factors for childhood burns: a case-control study of Ghanaian children

STUDY OBJECTIVE

To study risk factors for childhood burns in order to identify possible preventive strategies.

DESIGN

Case-control design with pair matching of controls to cases in relation to age, sex, and area of residence. The cases and controls were identified by a community based, multisite survey. The effects of host and socioenvironmental variables reported by mothers were investigated in a multivariate analysis using conditional logistic regression.

SETTING

A developing country setting the Ashanti Region in Ghana.

PARTICIPANTS

These comprised 610 cases aged 0-5 years who had been burned (as evidenced by a visible scar) and 610 controls with no burn history.

MAIN RESULTS

The presence of a pre-existing impairment in a child was the strongest risk factor in this population (OR = 6.71; 95% CI 2.78, 16.16). Other significant risk factor included: sibling death from a burn (OR = 4.41; 95% CI 1.16, 16.68); history of burn in a sibling (OR = 1.79; 95% CI 1.24, 2.58); and storage of a flammable substance in the home (OR = 1.51; 95% CI 1.03; 2.21). Maternal education had a protective effect against childhood burns, although this effect was not strong (OR = 0.76; 95% CI 0.55, 1.05).

CONCLUSIONS

Community programmes to ensure adequate child supervision and general child wellbeing, particularly for those with impairments, as well as parental education about burns are recommended, to reduce childhood burns in this region of Ghana. The public should bed advised against storing flammable substances in the home.

Childhood burns in Ghana: epidemiological characteristics and home-based treatment

The objectives of this research were to study the epidemiological characteristics and home-based treatment of childhood burns in the Ashanti Region of Ghana. Children aged 0-5 years with a burn history were identified through a community-based, multisite survey. A standard questionnaire was administered to mothers of 630 of these children to elicit information on their sociodemographic characteristics and the circumstances of the burn event. Ninety-two per cent of the burns occurred in the home, particularly in the kitchen (51 per cent) and the house yard (36 per cent), with most of them happening in the late morning and around the evening meal. The main causes of the burns were scalds (45 per cent), contact with a hot object (34 per cent) and flame (20 per cent). 'Cool' water was applied to the burned area in 30 per cent of cases. Otherwise, treatment with a traditional preparation was the most popular first-aid choice. Since a considerable proportion of burns happened between meals when children 'play with fire' in the house yard, the provision of alternative play activities and community play areas may reduce the incidence of burns to these children. Secondly, we recommend that education on first-aid management of burns be intensified, with special emphasis on alternatives to the use of traditional preparations.

International comparisons of injury mortality in the elderly: issues and differences between New Zealand and the United States

BACKGROUND

International comparisons of mortality rates for injury, as for other conditions, can suggest priorities for further research and intervention. However, variability in the assignment of underlying cause, especially among the elderly, may lead to difficulty in interpreting cross-national differences in death rates. Despite similarities between the two countries, the injury death rate for ages < or = 65 in New Zealand is substantially higher than the United States rate. The objective of this study was to investigate possible reasons for this difference.

METHODS

We used data not previously reported for New Zealand to calculate the cause-specific injury death rates for ages > or = 65, compared them with US rates, and examined other injury rates that could help explain the observed difference.

RESULTS

The New Zealand death rate from falls for ages > or = 65 was nearly three times the US rate (92 versus 32 per 100,000), causing the death rate for all injuries in this age group to be 34% higher in New Zealand (153 versus 114 per 100,000). However, hospitalization rates for both falls and hip fractures are similar for the two countries.

CONCLUSIONS

The substantially higher fall injury death rates for older New Zealanders are not fully explained by differences in the incidence of falls resulting in injury nor the case fatality rate for fall-related injury. US injury death rates based on underlying cause of death might be similar to New Zealand rates, and thus substantially higher, if subjected to comparable procedures for the completion and coding of death certificates. As in studies of other conditions, international comparisons of injury death rates based on underlying cause, especially in studies of the elderly, must consider variation between countries in death certification and coding practices.

Serotonergic modulation of striatal dopamine measured with positron emission tomography (PET) and in vivo microdialysis

Positron emission tomography and in vivo microdialysis were used to study serotonin's role in modulating striatal dopamine. Serial PET studies were performed in adult female baboons at baseline and following drug treatment, using the dopamine (D2) selective radiotracer, 11C-raclopride. The serotonergic system was manipulated by administration of the selective 5-HT reuptake inhibitor, citalopram, or by serotonergic (5-HT2) receptor blockade (using altanserin, a 5-HT2 antagonist). 11C-Raclopride time-activity data from striatum and cerebellum were combined with plasma arterial input functions and analyzed by calculating a distribution volume as described previously (Logan et al., 1990). Additionally, in vivo microdialysis studies were performed in awake freely moving rats using similar pharmacologic challenges plus SR 46349B, a new highly selective 5-HT2 receptor antagonist. Altanserin and SR 46349B increased extracellular striatal dopamine concentrations (35% and 910%, respectively) while altanserin decreased striatal 11C-raclopride binding (37%). Citalopram, however, decreased extracellular striatal dopamine concentrations (50%) and increased 11C-raclopride binding (33%). These data demonstrate that 5-HT-selective drugs produce changes in striatal dopamine that can be measured noninvasively with PET. Furthermore, the PET data obtained from anesthetized baboons is consistent with in vivo microdialysis data obtained from awake and freely moving rats. Finally, these studies have implications for understanding the therapeutic efficacy of atypical neuroleptics and their utility for treating schizophrenia and affective disorders.

Terephthalic acid: a dosimeter for the detection of hydroxyl radicals in vitro

Hydroxylation reactions of aromatic compounds have been used to detect hydroxyl radicals produced by gamma irradiation and ultrasound. The present study investigated the suitability of terephthalic acid (THA) as a hydroxyl radical dosimeter for general use in biologically relevant reactions. Hydroxyl radicals were generated by: (1) irradiating THA with a 254 nm ultraviolet light; (2) irradiating with gamma rays from a cesium source; and (3) generating hydroxyl radicals with 1 mM H2O2 and 10 microM Cu+2. In each of the three experiments, a fluorescent product was generated which exhibited identical fluorescent excitation and emission spectra. THA is non-fluorescent, eliminating the problem of a high initial background. Because THA has four identical ring hydrogens, only one mono-hydroxylated isomer was formed. The hydrogen peroxide reaction was dependent on the presence of a metal and cupric ions were effective in enhancing the reaction. With a Cu+2 concentration of 10 microM, the reaction was linear between 0-30 mM H2O2. Catalase abolished the reaction at a concentration of 100 micrograms/ml and the effects could still be observed at 10 ng/ml, consistent with the very high rate at which catalase destroys hydrogen peroxide. Tertbutyl- hydroperoxide did not generate any fluorescence in this system which makes THA a very specific detector of hydroxyl radicals.

Distribution of messenger RNAs encoding enkephalin, substance P, somatostatin, galanin, vasoactive intestinal polypeptide, neuropeptide Y, and calcitonin gene-related peptide in the midbrain periaqueductal grey in the rat

The midbrain periaqueductal grey matter (PAG) has numerous functional roles that include mediating nociceptive inhibition and integrating behavioural and physiological responses to potentially threatening or stressful stimuli. Underlying these behaviours is the diverse interconnectivity of this region, and it is possible that neurochemical subdivisions within the PAG reflect the functional properties of the different PAG regions. In this study, using in situ hybridization, we have investigated the distribution in the rat PAG of the messenger ribonucleic acids (mRNAs) encoding seven neuropeptides: enkephalin (ENK), substance P (SP), somatostatin (SST), galanin (GAL), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), and calcitonin gene-related peptide (CGRP). Each peptide mRNA had a distinct topographical distribution in the PAG. Preproenkephalin A (ENK) mRNA-expressing cells were found at all levels of the PAG in three distinct longitudinal columns. Preprotachykinin A (SP)-expressing cells were found at all levels of the PAG, principally in the Edinger-Westphal nucleus and the lateral and dorsal PAG. There was a column of neurons producing mRNA-encoding somatostatin that extended along the rostrocaudal extent of the ventrolateral PAG; there were also labelled cells in the dorsal and dorsolateral subdivisions at some levels of the PAG. Galanin mRNA-producing neurones were limited to the dorsal raphe nucleus and to a second population in the ventral border of the aqueduct. VIP mRNA-producing neurones were found in very localized regions of the PAG, including the cell-sparse region immediately ventral to the aqueduct and the ventral part of the dorsal raphe nucleus. NPY mRNA-producing neurones were localized mainly in some cells of the Edinger-Westphal nucleus and dorsal raphe nucleus. CGRP mRNA-expressing neurons were limited to the oculomotor and trochlear nucleus. The results showed a topographical distribution of neuropeptides over the rostrocaudal extent of the PAG that is compatible with the emerging theory that the anatomical and functional specificity of the PAG is expressed in the form of longitudinally arranged neuronal columns that extend for varying distances along the rostrocaudal axis of the midbrain PAG.

Drinking behavior in relation to cause of death among US adults

OBJECTIVES

Alcohol involvement is common in many fatal injuries. This study examines drinking behavior in a nationally representative sample of US adult decedents aged 25 through 64 years and its association with cause of death.

METHODS

Proxy-reported information from the 1986 National Mortality Followback Survey was used to profile the decedents' usual frequency and quantity of drinking. The association of drinking behavior with underlying cause of death was assessed while adjusting for demographic characteristics.

RESULTS

Of the decedents, 17% were daily drinkers, 22% usually consumed five drinks or more per occasion, and 27% were classified as heavier drinkers. Persons who died of injury drank more frequently and heavily than those who died of disease. The adjusted odds ratio of injury's being the underlying cause of death was 1.4 (95% confidence interval [CI] = 1.1, 1.8) for daily drinkers, 1.5 (95% CI = 1.1, 2.0) for those drinking five or more drinks per occasion, and 1.4 (95% CI = 1.1, 1.7) for heavier drinkers.

CONCLUSIONS

Daily drinking, binge drinking, and heavier drinking were each associated with an increased likelihood of injury as the underlying cause of death. Persons who were young, male, Native American, or divorced or separated were more likely to drink frequently and heavily.

Effects of graded levels of bentonite on serum clinical profiles, metabolic hormones, and serum swainsonine concentrations in lambs fed locoweed (Oxytropis sericea)

To determine which clay minerals have the potential to bind swainsonine, an in vitro screening procedure was conducted. Twenty compounds were screened in one replicated in vitro trial. A commercially available bentonite bound approximately 10% swainsonine and was chosen for use in a subsequent lamb feeding trial. Twenty fine-wool lambs (30.5 +/- .7 kg) were assigned to one of five treatments (four lambs/treatment). Treatments included 1) positive control, 100% sorghum sudangrass hay, 2) 85% sorghum sudangrass:15% locoweed (Oxytropis sericea, 430 ppm [DM basis] of swainsonine) +0 g of bentonite, 3) Treatment 2 + 14 g of bentonite, 4) Treatment 2 + 28 g of bentonite, and 5) Treatment 2 + 42 g of bentonite. Lambs were fed the experimental diets for 35 d and were then fed the positive control diet for an additional 21 d. Lambs were weighted and blood was collected via jugular venipuncture weekly from d 0 through 56. On d 35, additional blood samples were collected 1, 2, 4, and 8 h after feeding. Weekly blood samples were analyzed for serum clinical chemistry profiles, and additional blood samples collected on d 35 were analyzed for serum metabolic hormones and serum swainsonine concentrations. Within 1 wk, serum alkaline phosphatase and glutamic oxaloacetic transaminase activities increased markedly (P < .05) in lambs fed locoweed. Serum insulin, growth hormone, and prolactin concentrations were not affected by feeding locoweed, but serum triiodothyronine and thyroxine concentrations were decreased by approximately 50% (P < .05) in lambs fed locoweed.(ABSTRACT TRUNCATED AT 250 WORDS)

Divergent trends in childhood drowning rates, 1971 through 1988

OBJECTIVE

To examine national age-, race-, and sex-specific trends in unintentional drowning rates among US children aged 0 through 19 years.

DESIGN

National mortality data published by the National Center for Health Statistics and population data from the US Bureau of the Census were used in calculating age-, race-, and sex-specific drowning rates for 1971 through 1988. Time trends were analyzed using Poisson regression techniques.

SETTING

United States, 1971 through 1988.

MAIN OUTCOME MEASURE

Rates of death due to unintentional, non-boat-related drowning.

RESULTS

From 1971 through 1988, there were 45,680 unintentional, non-boat-related drowning deaths among 0- through 19-year-olds in the United States. Drowning rates declined sharply in older children (-5.8% per year in 10- through 14-year-olds and -5.4% per year in 15- through 19-year-olds), declined only slightly in toddlers (-1.6% per year in 1- and 2-year-olds), and actually increased in infants (+1.6% per year in those children younger than 1 year).

CONCLUSION

Drowning rates in toddlers have changed little over time despite the availability of effective prevention strategies such as pool fencing. In older children, drowning rates have declined dramatically despite the lack of clear preventive initiatives. Prevention interventions targeted specifically at the infant and toddler age groups should receive priority.

Effects of central cholinergic blockade on striatal dopamine release measured with positron emission tomography in normal human subjects

Previously we demonstrated that positron emission tomography (PET) can be used to measure changes in the concentrations of synaptic dopamine and acetylcholine. Whether induced directly or indirectly through interactions with other neurotransmitters, these studies support the use of PET for investigating the functional responsiveness of a specific neurotransmitter to a pharmacologic challenge. In an extension of these findings to the human brain, PET studies designed to measure the responsiveness of striatal dopamine release to central cholinergic blockade were conducted in normal male volunteers using high-resolution PET and [11C]raclopride, a D2-dopamine receptor antagonist. [11C]Raclopride scans were performed prior to and 30 min after systemic administration of the potent muscarinic cholinergic antagonist, scopolamine (0.007 mg/kg). After scopolamine administration, [11C]raclopride binding decreased in the striatum (specific binding) but not in the cerebellum (nonspecific binding) resulting in a significant decrease, exceeding the test/retest variability of this ligand (5%), in the ratio of the distribution volumes of the striatum to the cerebellum (17%). Furthermore, scopolamine administration did not alter the systemic rate of [11C]raclopride metabolism or the metabolite-corrected plasma input function. These results are consistent not only with the known inhibitory influence that acetylcholine exerts on striatal dopamine release but also with our initial 18F-labeled N-methylspiroperidol and benztropine studies. Thus these data support the use of PET for measuring the functional responsiveness of an endogenous neurotransmitter to an indirect pharmacologic challenge in the living human brain.

Distribution, Density, and Diversity of Heterodera glycines in Missouri

Between May, 1988, and July, 1992, the University of Missouri Plant Nematode Diagnostic Laboratory collected data on Heterodera glycines populations in Missouri by offering diagnostic services to soybean farmers. A greenhouse bioassay (free), egg count ($10/sample), and race determination test ($25) were conducted by request on soil samples submitted to the lab. Each test was offered for a specific purpose: the bioassay for fields not known to be infested; the egg count for population monitoring in fields with known infestations; and the race test for fields with a history of resistant cultivars. Of 818 samples submitted for bioassay on a H. glycines-susceptible soybean cultivar, 13 (1.6%) contained brown cysts but no white females, and 364 (45%) contained white females after 35 days in the greenhouse. Of 6,193 egg counts, 39% were either free of H. glycines or contained fewer than 500 eggs/250 cm(3) soil, the action threshold for Missouri. The remaining 61% ranged from 500-400,000 eggs/250 cm(3) soil (mean = 10,617). Eleven races were detected, with races 3 (45%) and 1 (23%) the most common. The data show that H. glycines is widespread in Missouri (with confirmed infestations in 80 of 114 counties), that most infested fields have population densities above the action threshold, and that there is considerable genetic diversity among H. glycines field populations.

Hepato-renal toxicosis characterized in sheep dosed intraruminally with snakeweed foliage (Gutierrezia spp)

To investigate the acute effects of snakeweed foliage (SW, Gutierrezia spp), 6 ruminally fistulated wethers (avg BW 78.6 kg) were dosed intraruminally (2/dose) with 454 g ground SW foliage, 227 g SW + 227 g alfalfa, or 454 g alfalfa daily for 5 d. Rumen fluid and blood samples were collected daily before SW dosage, and on day 6 the animals were euthanized and examined. At d 5, SW increased direct and indirect bilirubin indicating impaired hepatocyte function with biliary involvement and cholestasis. Gamma-glutamyl transpeptidase concentrations were elevated, and pale yellowish enlarged livers were observed in SW-dosed animals. Serum creatinine concentrations were increased 2-fold by SW, suggesting renal impairment. Rumens from dosed animals were compacted with hemorrhagic and necrotic mucosa suggesting SW-impaired rumen motility and microbial fermentation. One wether dosed with 454 g SW died after SW dosage for 2 d.

Adverse effects of vagotomy on ethanol-induced gastric injury in the rat. Absence of a role for glutathione redox cycle

Truncal vagotomy is known to aggravate the damaging effects of alcohol-induced gastric injury and prevent the occurrence of adaptive cytoprotection against such injury by a mild irritant. This study was undertaken to determine whether aberrations in glutathione (GSH) metabolism were responsible for these vagotomy-induced effects. Fasted rats (6-8/group) were subjected to truncal vagotomy and pyloroplasty or sham vagotomy and pyloroplasty. One week later they were given 2 ml of oral saline or the mild irritant, 25% ethanol (EtOH). Thirty minutes following such treatment, animals were either sacrificed or orally received 2 ml of 100% EtOH and then were sacrificed 5 min later. At sacrifice, in each experimental group, stomachs were removed and either evaluated macroscopically for the degree of injury involving the glandular gastric epithelium or samples of the mucosa were prepared for measurement of total GSH levels or GSH peroxidase (GPX) and GSH reductase (GRT) activity. In nonvagotomized animals, saline treatment prior to 100% EtOH exposure resulted in injury to the glandular epithelium involving approximately 18%. Treatment with 25% EtOH prior to 100% EtOH exposure virtually abolished this injury. In vagotomized animals, 100% EtOH elicited almost three times the amount of injury observed in the nonvagotomized state and the protective effect of 25% EtOH pretreatment was prevented. Effects of the various treatment modalities on GPX and GRT activity were not significantly different from control values. When mucosal GSH results were plotted against the presence or absence of gastric injury among the various groups studied, no significant correlation was apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Case-fatality rates by body part affected and trends in hospitalized burns in Maryland, 1981-90

This study was undertaken (i) to determine in-hospital case-fatality rates (CFRs) by severity using body part(s) affected as a proxy, and (ii) to examine the trends in hospitalized burns regarding CFRs. The study used the Health Service Cost Review Commission non-confidential Maryland hospital discharge data for the years 1981-90. CFRs were computed as percentages of hospitalized burns that died. Chi-square tests were used to assess homogeneity for categorical variables and to examine linear trends. The CFR for hospitalized burns was 2.9 per cent. CFR was highest among the elderly (13.1 per cent) and for burns affecting multiple specified sites (7.4 per cent), and lowest among children (1.1 per cent) and for upper limb burns (0.22 per cent). Burn CFR increased overall by 59 per cent for 1981-90, with a decreasing rate only in children. However, after controlling for age and degree of burn no significant change in trend in CFRs over the 10-year period was evident. The findings demonstrate that while child burn fatality seems to have declined, the elderly continue to have high CFR for burns regardless of the body part affected, and that the CFRs for hospitalized burns remained constant between 1981 and 1990 in Maryland despite considerable advances in treatment.

Toxicity of CI-949, a novel anti-allergy agent

The toxicity of CI-949, an effective inhibitor of allergic mediator release in pharmacology models, was evaluated in rodents and dogs. Median lethal doses at 24-hr postdose ranged from 343 to 453 mg/kg in mice and 806 to 2058 mg/kg in rats. Delayed toxicity was observed at 300 mg/kg and greater in mice and at 500 mg/kg and greater in rats. Mortality and clinical intolerance occurred in rats at 200 and 400 mg/kg in the subacute studies, and at 100 and 150 mg/kg in the 13-week study. In rats, dose-dependent lymphoid tissue atrophy and depletion or necrosis of lymphocytes in lymphoid tissues were seen in deaths and moribund terminations. Although doses up to 60 mg/kg administrated for 2 weeks to dogs were well tolerated, 60 and 120 mg/kg in the 13-week dog study were poorly tolerated. Cutaneous sores, mucocutaneous purulent discharge, emesis, diarrhea, and weight loss were identified at these lethal doses. Histopathologic changes in dogs included myocardial, vascular and soft tissue inflammation, and gastric ulceration at 60 and 120 mg/kg, and thymic atrophy at 20 mg/kg and greater. Doses of 10 and 50 mg/kg were no-effect doses in 13-week repeated dose studies in dogs and rats, respectively. These results were used to support initial human clinical trials of CI-949.

Characterization of toxicosis in sheep dosed with blossoms of sacahuiste (Nolina microcarpa)

To characterize more fully sacahuiste (Nolina microcarpa Watson) toxicosis in sheep and to evaluate benefits of supplemental Zn, sheep were dosed intraruminally with sacahuiste blossoms. In Trial 1, eight fine-wool sheep (47 +/- 2 kg BW) were fed alfalfa hay at 1% of BW daily and dosed intraruminally with inflorescences amounting to 1% of BW daily, in three portions per day, for 10 d. Four sheep were dosed intraruminally with aqueous ZnSO4 (30 mg of Zn/kg BW) daily for 3 d before initial sacahuiste dosing and on alternate days thereafter, and four sheep were untreated with Zn. Toxicosis was evident within 24 h after initial sacahuiste dosage, involving inappetence, depression, hypokalemia, hypophosphatemia, hyperbilirubinemia, and elevated serum enzymes (alkaline phosphatase, creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and gamma-glutamyl transpeptidase). One sheep (untreated with Zn) died on d 3. Aqueous ZnSO4 alleviated inappetence and suppressed elevation of serum urea N and creatinine but did not suppress other changes in serum clinical profiles. In Trial 2, sacahuiste inflorescences were ruminally dosed into 12 fine-wool wethers (29 +/- 2 kg BW) in amounts equalling 0, .25, .50, .75% of BW per day, and chopped alfalfa hay was provided at 1.75% of BW per day for 14 d. Sacahuiste inflorescenses dosed at .75% of BW elicited severe toxicosis within 24 h, and dosage at .50 or .25% of BW per day increased (P = .12) serum bilirubin. Ruminal fluid pH, mean particle retention time, and particulate passage rate were not affected (P > .10) by sacahuiste, but ruminal fluid passage rate increased 1.6-fold (P < .10) and ruminal fluid volume decreased by 60% (P < .10) in sheep given inflorescenses amounting to .50% of BW daily. Sacahuiste inflorescenses dosed intraruminally at .75% of BW per day elicited ruminal impaction with severe hepatotoxicosis, and dosages amounting to .50% or .25% of BW per day caused similar trends.

Embryonic mortality in Sprague-Dawley rats induced by snakeweed (Gutierrezia microcephala)

Three experiments were conducted to determine the effects of ingested snakeweed foliage (SW) on gestating rat embryos. Mature female Sprague-Dawley rats were paired with male rats and after breeding were randomly allotted to diets containing up to 15% SW. Feeding SW caused a decrease (P < .01) in the percentage of live embryos and markedly increased (P < .01) the percentage of dead or resorbed embryos. Snakeweed decreased (P < .01) feed intake in a dose-dependent manner and caused BW loss (P < .01) compared with control animals. However, decreased feed intake had no effect on gestating embryos. Rats fed the control diet, with intakes restricted to equal the average intake of rats fed SW, and those with ad libitum access to the control diet had similar percentages of live and dead embryos (P > .10). Serum clinical profiles reflected undernutrition (decreased triglycerides and cholesterol; P < .01) and mild toxicosis (elevated blood urea nitrogen, creatinine, and bilirubin; P < .01). Because fluid accumulation was noted in the uterus of several rats fed SW, a uterine weight bioassay was conducted. Snakeweed, fed as 10% of the total diet, decreased (P < .01) uterine weight of immature Sprague-Dawley rats. Ingestion of SW during early gestation caused embryonic mortality that could not be attributed to undernutrition or estrogenicity.

Alterations in rat intestinal transit by morphine promote bacterial translocation

Translocation of enteric microorganisms from the intestinal tract to extraintestinal sites has been proposed as an early step in the development of gram-negative sepsis. This study examined the role of altered bowel transit in influencing intestinal bacteriostasis and bacterial translocation using morphine as a pharmacologic inhibitor of such transit. In the first experiment, either normal saline (N = 8) or morphine sulfate (20 mg/kg; N = 8) was injected subcutaneously. Two hours later, morphine (7.5 mg/kg) was infused subcutaneously for an additional 22 hr; control animals received saline alone. After completion of this regimen, a volume of 0.2 ml of 2.5 mM FITC dextrans (10,000 daltons) were injected intraduodenally in each group. The bowel was removed 25 min later, divided into 5-cm segments, and the content of dextrans measured. Small bowel propulsion was expressed as the geometric center of the distribution of dextrans throughout the intestine (in percentage length of small bowel). Gut propulsion was significantly reduced after morphine treatment as compared to controls (32.8 +/- 8.2% vs. 55.8 +/- 4.0%; P < 0.01). In 16 additional rats, saline or morphine was again administered as described. After 24 hr, samples were obtained from the mesenteric lymph node (MLN) complex, blood, spleen, liver, duodenum, jejunum, ileum, and cecum for standard bacteriology. The bacterial counts increased significantly in each intestinal segment following morphine treatment. Microorganisms translocated to the MLN complex in 5, and to distant sites in four of eight morphine-treated animals, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)