Snapshot of Vibrio parahaemolyticus densities in open and closed shellfish beds in Coastal South Carolina and Mississippi.

Vibrio parahaemolyticus is a Gram negative, halophilic bacterium that is ubiquitous in warm, tropical waters throughout the world. It is a major cause of seafood-associated gastroenteritis and is generally associated with consumption of raw or undercooked seafood, especially oysters. This study presents a snapshot of total V. parahaemolyticus densities in surface waters and shellstock American oysters (Crassostrea virginica) from open and closed shellfish harvesting areas, as well as "more rural areas" on two different US coasts, the Atlantic and the Gulf. Sampling was conducted from 2001 to 2003 at five sites near Charleston/Georgetown, SC and at four locations in the Gulfport/Pascagoula, MS area. V. parahaemolyticus numbers were determined by a direct plating method using an alkaline-phosphatase-labeled DNA probe targeting the species-specific thermolabile hemolysin gene (tlh) that was used for identification of bacterial isolates. The greatest difference between the two coasts was salinity; mean salinity in SC surface waters was 32.9 ppt, whereas the mean salinity in MS waters was 19.2 ppt, indicating more freshwater input into MS shellfish harvesting areas during the study period. The mean V. parahaemolyticus numbers in oysters were almost identical between the two states (567.4 vs. 560.1 CFU/g). Bacterial numbers in the majority of surface water samples from both states were at or below the limit of detection (LOD = <10 CFU/mL). The bacterial concentrations determined during this study predict a low public health risk from consumption of oysters in shellfish growing areas on either the Gulf or the Atlantic US coast.

Exploring fecal indicator bacteria in a constructed stormwater wetland.

Microbial pollution in surface waters is a concern throughout the world, with both public health and economic implications. One contributing source to such pollution is stormwater runoff, often treated using various types of stormwater control measures. However, relatively little is known regarding microbe sequestration in constructed stormwater wetlands (CSWs), one type of commonly installed stormwater control measure. In this study, indicator bacteria concentrations in both the water and sediment of a CSW were evaluated at multiple locations. Results suggested that fecal coliform concentrations in stormwater runoff decrease through the system, with relatively consistent concentrations noted throughout the second half of the wetland. This potentially indicates a baseline concentration of fecal coliform is present due to internal processes such as animal activity and microbial persistence. However, wetland sediments showed little E. coli present during most sampling events, with minimal patterns existing with respect to sediment sampling location. CSW designs should promote optimization of hydraulic retention time and minimization of stormwater velocities to promote sedimentation and degradation of microbes by way of wetland treatment functions.

Randomized Controlled Trial of a Cohesive Eight-Week Evolution Unit That Incorporates Molecular Genetics and Principles of the Next Generation Science Standards.

In response to calls for curricular materials that integrate molecular genetics and evolution and adhere to the K-12 Next Generation Science Standards (NGSS), the Genetic Science Learning Center (GSLC) at the University of Utah has developed and tested the "Evolution: DNA and the Unity of Life" curricular unit for high school biology. The free, 8-week unit illuminates the underlying role of molecular genetics in evolution while providing scaffolded opportunities to engage in making arguments from evidence and analyzing and interpreting data.  We used a randomized controlled trial design to compare student learning when using the new unit with a condition in which teachers used their typical (NGSS-friendly) units with no molecular genetics. Results from nationwide testing with 38 teachers (19 per condition) and their 2269 students revealed that students who used the GSLC curriculum had significantly greater pre/post gain scores in their understanding of evolution than students in the comparison condition; the effect size was moderate. Further, teacher implementation data suggest that students in the treatment condition had more opportunities to engage in argumentation from evidence and have in-class discussions than students in the comparison classes. We consider study implications for the secondary and postsecondary science education community.

Mapping of pain circuitry in early post-natal development using manganese-enhanced MRI in rats.

Premature or ill full-term infants are subject to a number of noxious procedures as part of their necessary medical care. Although we know that human infants show neural changes in response to such procedures, we know little of the sensory or affective brain circuitry activated by pain. In rodent models, the focus has been on spinal cord and, more recently, midbrain and medulla. The present study assesses activation of brain circuits using manganese-enhanced magnetic resonance imaging (MEMRI). Uptake of manganese, a paramagnetic contrast agent that is transported across active synapses and along axons, was measured in response to a hindpaw injection of dilute formalin in 12-day-old rat pups, the age at which rats begin to show aversion learning and which is roughly the equivalent of full-term human infants. Formalin induced the oft-reported biphasic response at this age and induced a conditioned aversion to cues associated with its injection, thus demonstrating the aversiveness of the stimulation. Morphometric analyses, structural equation modeling and co-expression analysis showed that limbic and sensory paths were activated, the most prominent of which were the prefrontal and anterior cingulate cortices, nucleus accumbens, amygdala, hypothalamus, several brainstem structures, and the cerebellum. Therefore, both sensory and affective circuits, which are activated by pain in the adult, can also be activated by noxious stimulation in 12-day-old rat pups.

Matrix metalloproteinase expression in human retinal microvascular cells.

The degree of hyperglycemia correlates with the development of diabetic retinopathy. We investigated the effect of glucose on the expression of matrix metalloproteinase (MMP)-2 and MMP-9 (72-kDa and 92-kDa type IV collagenases, respectively) by human retinal microvascular endothelial cells (HRECs). Cultured HRECs from nondiabetic and diabetic donors were exposed to 5 or 30 mmol/l glucose. Using gelatin zymography, conditioned medium (CM) from all cultures revealed a gelatinolytic band migrating at 65 kDa (representing the proform of MMP-2 that runs at 72 kDa under reducing conditions). This band was unchanged by glucose exposure or the disease state of the donors. CM from nondiabetic HREC cultures demonstrated an additional proteolytic activity migrating at 90 kDa when cells were exposed to 30 mmol/l glucose, but not when they were exposed to 5 mmol/l glucose. This same activity was seen in CM from HREC cultures of diabetic origin in the presence of both 5 and 30 mmol/l glucose. Western analysis confirmed the identity of the 65-kDa band as MMP-2. The anomalous activity at 90 kDa was identified as MMP-2 associated and co-migrating with a fibronectin fragment. Competition-based reverse transcription-polymerase chain reaction revealed that nondiabetic and diabetic HRECs expressed constitutively mRNA for MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, and fibronectin. After exposure to 5 or 30 mmol/l glucose, no changes were detected in mRNA levels in MMP-2 or MMP-9, their inhibitors TIMP-1 and TIMP-2, or fibronectin in either nondiabetic or diabetic HREC cultures. These results support the notion that modulation of MMP function by extracellular matrix components occurs in response to glucose and may be relevant to the development of diabetic retinopathy.

Plasma lipoprotein levels as predictors of cardiovascular death in women.

BACKGROUND: The association of lipoprotein levels with cardiovascular disease (CVD) is less well understood in women than in men. To better characterize any relationships, associations between CVD death and total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol and triglyceride levels in women were explored using data from female participants in the Lipid Research Clinics' Follow-up Study. METHODS: Using a sample of 1405 women aged 50 to 69 years from the Lipid Research Clinics' Follow-up Study, age-adjusted CVD death rates and summary relative risk (RR) estimates by categories of lipid and lipoprotein levels were calculated. Multivariate analysis was performed to provide RR estimates adjusted for other CVD risk factors. RESULTS: Average follow-up was 14 years. High-density lipoprotein and triglyceride levels were strong predictors of CVD death in age-adjusted and multivariate analyses. Low-density lipoprotein and total cholesterol levels were poorer predictors of CVD mortality. After adjustment for other CVD risk factors, HDL levels less than 1.30 mmol/L (50 mg/dL) were strongly associated with cardiovascular mortality (RR = 1.74; 95% confidence interval [CI], 1.10 to 2.75). Triglyceride levels were associated with increased CVD mortality at levels of 2.25 to 4.49 mmol/L (200 to 399 mg/dL) (RR = 1.65; 95% CI, 0.99 to 2.77) and 4.50 mmol/L (400 mg/dL) or greater (RR = 3.44; 95% CI, 1.65 to 7.20). At total cholesterol levels of 5.20 mmol/L (200 mg/dL) or greater and at all levels of LDL and triglycerides, women with HDL levels of less than 1.30 mmol/L (< 50 mg/dL) had CVD death rates that were higher than those of women with HDL levels of 1.30 mmol/L (50 mg/dL) or greater. CONCLUSIONS: High-density lipoprotein and triglyceride levels are independent lipid predictors of CVD death in women. Cholesterol screening guidelines should be re-evaluated to reflect the importance of HDL and triglyceride levels in determining CVD risk in women.

Effects of oral versus transdermal estrogen on the growth hormone/insulin-like growth factor I axis in younger and older postmenopausal women: a clinical research center study.

To compare the effects of oral vs. transdermal estrogens on GH secretion and levels of circulating insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) in younger vs. older postmenopausal women, we conducted a placebo-controlled, cross-over trial of 6 weeks of oral conjugated estrogen (1.25 mg daily) or transdermal estradiol (100 micrograms/day) administered in random order and separated by an 8-week, treatment-free interval. Sixteen healthy postmenopausal women, ages 49-75 yr, were studied on an NIH-funded General Clinical Research Center grant. Data were analyzed for the combined group as well as in the younger ( 62 yr, n = 8). Spontaneous GH secretion, as assessed by 12-h overnight blood sampling at 20-min intervals; GH responsiveness to i.v. bolus injection of GHRH; and levels of serum IGF-I and IGFBP-3, before and after GHRH stimulation, were measured at enrollment and after 6 weeks of each estrogen treatment. Before estrogen treatment, spontaneous nocturnal GH secretion and morning IGF-I levels tended to be lower, IGFBP-3 levels did not differ, and GHRH-stimulated GH levels were significantly reduced in older vs. younger postmenopausal women. Oral estrogens increased spontaneous GH secretion, decreased serum IGF-I levels, and did not alter IGFBP-3 levels, whereas transdermal estrogens did not alter nocturnal GH secretion or morning IGF-I levels and decreased IGFBP-3 levels only in the older women. GHRH-stimulated GH levels were similar before and after oral or transdermal estrogen treatment. In contrast, after, GHRH administration, IGF-I levels were decreased only with oral estrogens, whereas IGFBP-3 levels were decreased with both oral (younger women only) and transdermal (younger and older women) estrogens. We conclude that, in postmenopausal women, oral and transdermal estrogens exert differing effects on the GH/IGF-I axis, but neither form of estrogen completely reverses the known age-related reductions in spontaneous or GHRH-stimulated GH and IGF-I.

Estrogen replacement reverses endothelial dysfunction in postmenopausal women.

PURPOSE: To measure the effect of long-term clinical hormone replacement therapy on brachial artery vasomotor responses, and to compare these responses in premenopausal and postmenopausal women. PATIENTS AND METHODS: We studied 23 postmenopausal women, including 18 who were evaluated prior to starting clinically indicated oral hormone replacement therapy. Twelve postmenopausal women received estrogen alone, the other 6 were treated with estrogen/medroxyprogesterone combinations. Eleven premenopausal volunteers served as a comparison group. Change in brachial artery diameter in response to postischemic hyperemic flow and sublingual nitroglycerin was measured by ultrasound. RESULTS: The 18 postmenopausal subjects receiving hormone replacement showed a progressive improvement in their postischemic vasodilation. Mean (+/-SD) postischemic vasodilation was 0.4%+/-7.1% prior to estrogen replacement. There were significant increases in postischemic vasodilation of 4.8%+/-6.6% after 1 month and 8.3%+/-3.4% after 6 months of estrogen replacement. The response to nitroglycerin was similar at all time points studied. Women with the most abnormal responses to hyperemic flow at baseline demonstrated the greatest improvement after 6 months of hormone replacement therapy. Premenopausal and postmenopausal subjects differed in their response to hyperemic flow, with premenopausal women showing 5.8% vasodilatation compared with a 0.6% vasodilation in postmenopausal women (P=0.046). CONCLUSIONS: Endothelial function is abnormal in many postmenopausal women compared with premenopausal women, and in some postmenopausal women it can be enhanced by estrogen replacement therapy. This effect may increase with prolonged use.

The in vitro differentiation of pleomorphic Trypanosoma brucei from bloodstream into procyclic form requires neither intermediary nor short-stumpy stage.

Our studies on the in vitro differentiation of a pleomorphic Trypanosoma brucei strain TREU667 indicate that the parasite differentiates directly from long-slender into procyclic form when incubated in Cunningham's medium at 26 degrees C. The intermediary and the short-stumpy bloodstream forms harvested from infected mice can also differentiate directly into procylic form in vitro with time courses similar to that for the long-slender form. Thus, none of the three bloodstream forms appear to be significantly better preadapted for differentiation. Tricarboxylic acid (TCA) cycle intermediates cis-aconitate and L-citrate can shorten the initial lag phase of the differentiation, but an essential trigger appears to be the temperature shift from 37 degrees C to 26 degrees C, when other TCA cycle intermediates such as L-proline, L-malate, alpha-ketoglutarate, fumarate and succinate are present in Cunningham's medium. The ornithine decarboxylase (ODC) activity in T. brucei showed a gradual increase and the ODC mRNA level remained constant during the differentiation. DL-alpha-Difluoromethylornithine (DFMO), putrescine, dibutyryl cAMP and theophylline all exerted no discernible effect on the in vitro process, which suggests that neither cAMP increase nor polyamine depletion could be counted among the triggers of T. brucei differentiation. A monomorphic T. brucei strain EATRO110 was tested in the same medium at 26 degrees C but was unable to differentiate.

Transient inhibition of protein synthesis accompanies differentiation of Trypanosoma brucei from bloodstream to procyclic forms.

It has been widely believed that bloodstream forms of Trypanosoma brucei must be first transformed into intermediary and/or short-stumpy forms in the bloodstream of the mammalian host before differentiation to the procyclic culture form can occur. In our recent studies, the pleomorphic T. brucei strain TREU667 was found to differentiate directly from the long-slender bloodstream form to the procyclic form in Cunningham's medium at 26 degrees C [7]. In the present investigation, the same was found true for another pleomorphic strain of T. brucei, STIB366D. Four independent monomorphic strains of T. brucei were tested; two, #427 and EATRO164, were found capable of differentiating in vitro directly into procyclic forms, whereas the other two, TREU667/RP-56 and EATRO110, could not. There is thus no correlation between the capability of differentiating in vitro and the ability of being converted from long-slender to intermediary and short-stumpy bloodstream forms. Two additional markers for following differentiation, other than observing morphological changes, were tested. Assays for the emerging phosphoenolpyruvate carboxykinase (PEPCK) by immunoblottings worked well, with results agreeing closely with the morphological change. But immunoblottings of glycosomal phosphoglycerate kinase (gPGK) failed to demonstrate a significant decrease in the protein level upon completion of differentiation. Apparently, gPGK has a rather long half-life and is unsuitable as a marker of differentiation. When temperature was dropped from 37 degrees C to 26 degrees C at the starting point of in vitro differentiation, protein synthetic activity in the pleomorphic T. brucei TREU667 bloodstream form was decreased by 4-fold. When the activity was gradually brought back to and beyond the original level after a day's incubation, the profile of newly synthesized proteins was that of the procyclic form. A monomorphic variant of TREU667, RP-56, which is incapable of differentiating in vitro, has a much higher protein synthetic activity than its pleomorphic parent in the bloodstream form. This high activity and the bloodstream profile of proteins thus synthesized were unaffected by the decreased temperature in Cunningham's medium until cell death. We thus conclude that a general inhibition of protein synthesis in bloodstream forms caused by temperature drop may be among the early events triggering differentiation into the procyclic form.

The translation initiation site of recombinant Trypanosoma brucei ornithine decarboxylase varies with different promoters.

Expression of the Trypanosoma brucei ornithine decarboxylase (ODC) gene in Escherichia coli behind the lambda phage PR promoter led to the production of a recombinant enzyme having the same subunit molecular weight as the native enzyme [4]. However, when the same gene is expressed behind the tac promoter or the phoA promoter, the ODCs produced by the transformed E. coli have subunit molecular weights approximately 2 kDa higher than that of the native enzyme. Amino terminal sequencing of the recombinant proteins indicates that the ODC synthesized under control of the lambda PR promoter actually starts at the second methionine (Met23) of the open reading frame, whereas those produced in the latter two cases begin at the first methionine (Met1). Analysis of the 5'-end of T. brucei ODC mRNA supports the conclusion that translation initiates at Met23. We postulate that, for the lambda PR promoter, translation initiates at Met23 instead of Met1 because of the formation of a stable secondary structure in the region of the Met1 and the presence of a good E. coli consensus translation initiation site upstream of Met23. We have constructed a new plasmid using the pho A promoter to express recombinant T. brucei ODC starting at Met23 in large quantities.

Quantitation of the ras gene product in leukemic blast cells using enzymatic staining.

Few studies have focused on the significance of ras protein levels in human malignancy, in part because of the inherent difficulty in quantitation of the ras gene product. We have developed a method for the enzymatic determination of the ras gene product and have used this method for the quantitation of ras gene product levels in 19 patients with acute leukemia. This technique provides a practical means to assess p21 expression in leukemic cells ex vivo while avoiding the use of radioactive reagents. In addition, the mobility of the ras species of interest is determined. This assay should be easily modified for the use of other antibodies such as those reported to be specific for various ras species (i.e., H-, K- and N-ras), for specific ras mutations or for other nonras proteins. Because of the use of electrophoresis prior to quantitation of protein, the antibody used does not need to possess high specificity for the protein of interest.

Human trophoblast invasion. Autocrine control and paracrine modulation.

Development of the human placenta involves rapid invasion of the uterine wall by fetal trophoblasts, a process with certain similarities to tumor cell invasion. Unlike tumor invasion, however, this unique interaction between genetically dissimilar trophoblast and uterine cells is closely regulated and limited both temporally and spatially by mechanisms that are largely unknown. We have used a combination of two experimental approaches to study this process: immunolocalization using tissue sections to investigate trophoblast invasion in vivo, and a cell culture model that allows manipulation of the invasion process in vitro. The results show that invading trophoblasts express activated forms of metalloproteinases, adhesion molecules and the novel class I histocompatibility antigen, HLA-G, in a highly regulated manner during invasion. The behavior of cytotrophoblasts in vitro, removed from the influences of uterine cells, closely parallels their behavior in vivo, suggesting the existence of autocrine control mechanisms. However, studies examining the effect of growth factors and cytokines on trophoblast invasion suggest that molecules of uterine origin can modify this process. Thus, we hypothesize that the intrinsic invasiveness of these cells is controlled, at least in part, by the specialized environment of the uterus. Future studies will concentrate on identifying these factors and the specific trophoblast functions they modify.

Ovarian hyperandrogenism: the role of and sensitivity to gonadotropins.

To determine if ovarian hyperandrogenism represents enhanced gonadotropic stimulation, augmented ovarian sensitivity to gonadotropins, or both, we have undertaken to evaluate (1) the 24-hour integrated concentrations of serum total testosterone (T) and luteinizing hormone (LH) and (2) the ovarian response of T to exogenous gonadotropic stimulation. To this end, two groups of women, hyperandrogenic anovulatory (n = 4) and early follicular phase (n = 4) normally-cycling controls, were subjected to continuous blood withdrawal over 24 hours with a portable Cormed pump (Cormed Inc., Middleport, NY) and to exogenous stimulation with human chorionic gonadotropin. Our current observations support the notion that ovarian hyperandrogenism represents the combined impact of an overall increase in gonadotropic support coupled with augmented ovarian sensitivity to gonadotropic stimulation.

Venovenous bypass in adult orthotopic liver transplantation: routine or selective use?

BACKGROUND: The role of venovenous bypass (VVB) during orthotopic liver transplantation (OLT) remains controversial. The aims of this study were to evaluate the current role of VVB at all major centers in North America, to examine the results of OLT and complications of VVB between two periods with a strict policy for routine versus selective use of VVB, and to review the literature. STUDY DESIGN: A survey of 50 major liver transplant centers was conducted using mailed questionnaires. A retrospective chart review was performed for 547 OLT patients having transplantation during two distinct periods with a strict policy for routine versus selective use of VVB at the University of Toronto, Canada, and at Duke University Medical Center, Durham, North Carolina. The literature was reviewed with a focus on the benefits and indications for routine versus selective use of VVB. RESULTS: Thirty-eight (76%) of 50 centers responded. Sixteen (42%) of them used VVB routinely, with a reported complication rate of 10-30%. Lymphocele and hematoma were the most common complications, but patients having major vascular injury, air embolism, and death were reported. A recent change to selective use of VVB was reported in 30% of the centers (11 of 38). In the Duke-Toronto series, the complication rates were similar between the two periods, at 13.4% and 18.8%, respectively. The outcome of OLT was not influenced by the policy of routine or selective use of VVB. CONCLUSIONS: There is a trend away from the routine use of VVB during OLT. Intraoperative hemodynamic instability during the hepatectomy and a failed trial of hepatic venous occlusion were the most important criteria for using VVB. We conclude that VVB should be used selectively to avoid associated complications and to decrease operative time and costs.

Maternal smoking inhibits early human cytotrophoblast differentiation.

Differentiation of the specialized epithelial cells of the placenta, termed cytotrophoblasts, is a particularly important aspect of placental development during the first trimester of pregnancy. During this process cytotrophoblast stem cells either fuse to form the syncytium or aggregate to form cell columns that adhere to, then invade the uterus. We found that chorionic villi from early gestation placentas of mothers who smoke showed a marked reduction in cell columns, a defect that could not be corrected by placing them in culture. We used two different in vitro models to determine if nicotine plays a role in the etiology of this defect. Exposing early gestation chorionic villi from nonsmoking women to nicotine inhibited subsequent cell column formation in vitro. Nicotine also inhibited normal first trimester cytotrophoblast invasion, apparently by reducing the ability of treated cells to synthesize and activate the 92 kDa type IV collagenase, an important mediator of invasion in vitro. These results suggest that maternal cigarette smoking inhibits the trophoblast differentiation pathway that leads to column formation and uterine invasion. This effect, which is due at least in part to the effects of nicotine, may contribute to the growth retardation observed in fetuses of mothers who smoke during pregnancy.

Cross cultural communication to help physician assistants provide unbiased health care.

Teaching cross cultural communication typically involves instruction in differences between groups. As part of this course in cross cultural communication, six specific underserved population groups are introduced to students as a cultural experience. Additionally, instruction is provided to sensitize students to their personal biases and prejudices through videotaped mock interviews. The combination of instruction and experience forms a paradigm for teaching cross cultural communication in a way that has personal and immediate impact on faculty members and students. The model, "Differences + Discomforts = Discoveries," inhibits factionalizing and promotes depth of knowledge about underserved groups as well as personal awareness of prejudicial feelings. As a result, students learn techniques to provide unbiased health care to these, and other, populations.

Gastric necrosis after fundoplication: a novel approach for esophageal preservation.

An 11-year-old boy presented moribund, with massive abdominal distension. A Nissen fundoplication and gastrostomy tube had been established at age 2 years. After attempts to pass a nasogastric tube were unsuccessful, the old gastrostomy site was used to gain percutaneous access to the stomach resulting in release of gastric contents and stabilization of blood pressure and perfusion. During operation, massive gastric distention with gastric necrosis was found. Subtotal gastrectomy was performed with stapled closure of the distal intraabdominal esophagus and prepyloric region. Sump suction was placed in the proximal esophagus and the abdomen was drained widely. A distal esophageal perforation was apparent on postoperative day 19 confirmed by imaging and endoscopy. A nasoesophageal tube was passed into the abdomen, tied to a Jackson-Pratt drain, and the composite tube repositioned in the midesophagus allowing controlled proximal and distal drainage. Six months later, a Hunt-Laurence esophagojejunal pouch was created. At age 13, the child is clinically well, and enjoys 50% of his nutritional needs orally, with the remainder delivered overnight via tube feedings. This case describes gastric necrosis after gas bloat syndrome as a late complication of Nissen fundoplication. A novel approach to the management of distal esophageal perforation allowed preservation of a functional, intact native esophagus.

Pharmacokinetics of once-daily gentamicin dosing in pediatric patients.

BACKGROUND/PURPOSE: To achieve cost-effective health care in adults, once-daily aminoglycosides administration has been used and judged to be safe and efficacious. A similar strategy in children requires the characterization of pharmacokinetic parameters and the development of a therapeutic monitoring protocol for this antibiotic regimen. METHODS: A prospective, controlled, randomized (2:1) study was undertaken in 50 pediatric patients between June 1995 and September 1997. Children between 6 months and 18 years who required gentamicin therapy based on independent clinical assessment were eligible if they had normal renal function, no aminoglycoside allergies, were not neutropenic, or did not have cystic fibrosis. Measurements included a peak, 4-hour, 8-hour, and trough gentamicin levels to determine volume of distribution (Vd) and elimination constant (Ke). Ototoxicity and nephrotoxicity were monitored by pre- and postaudiology examinations and serial calculated creatinine clearance determinations, respectively. RESULTS: Thirty-three patients received 7.5 mg/kg every 24 hours, and 17 patients received 2.5 mg/kg every 8 hours. Most frequent indications for treatment were ruptured appendicitis (n = 19) followed by wound infections caused by trauma (n = 4), but the spectrum of treatment was broad including enteric, genitourinary, central nervous system, biliary, ophthalmologic, and orthopedic infections. Pharmacokinetic data indicated that 24-hour dosing resulted in higher peak levels compared with 8-hour dosing (20.4 +/- 45.4 v 7.2 +/- 6.2 mg/L, P < .0001) and lower trough levels (0.29 +/- .02 v 0.69 +/- 0.13, P < .0001), whereas rate of elimination constant and volume of distribution were not significantly different. No nephrotoxicity or ototoxicity has been noted in either group. CONCLUSIONS: These data confirm that once-daily dosing of gentamicin is a safe method of treatment that provides equivalent pharmacokinetics compared with traditional dosing and enhances bactericidal effect based on higher peak levels, avoids toxicity, and allows cost savings.

Hospital reimbursement for pediatric trauma care.

PURPOSE: Despite the proven efficacy of pediatric trauma centers, their continued development is threatened by the perception that their cost exceeds the reimbursement for their services. The authors reviewed actual reimbursement for a group of pediatric trauma patients and compared with that for a group of appendectomy patients chosen to reflect the authors' surgical population at large. METHODS: The records of 209 consecutively treated trauma patients and 37 age-matched appendectomy patients treated in 1992 and 1993 were reviewed. Trauma patients were divided into two groups: moderate injury (ISS < or = 9; n = 134) and serious injury (ISS > or = 10; n = 75). RESULTS: Hospital bills for the appendectomy patients were reimbursed at 72% of charges and 112% of costs. Payment was received at a mean of 36 days (range, 9 to 62 days) after discharge. Reimbursement for moderately injured patients was 104% of charges and 137% of costs and was received at a mean of 81 days (range, 3 to 270 days) after discharge. Six months postdischarge, reimbursement for seriously injured patients was 63% of charges and 86% of costs. Reimbursement was slow for some children who sustained severe injury, but as legal actions brought by patient's families were completed, open accounts were settled, and revenue in both groups totaled 76% of charges and 103% of costs 18 months postdischarge. CONCLUSION: Hospital reimbursement for care at a level I pediatric trauma center exceeds 75% of charges and 100% of costs, no different from the overall rate for the general hospital surgical population. Analysis of reimbursement rates for trauma patients may be time-dependent.