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Biomedical subjects

R W Yurt

Publications and source records attributed to R W Yurt.

At least 19 recordsLinked to original sources
PubMed2001

Household oven doors: a burn hazard in children.

Contact with hot oven doors is an important cause of burns in pediatric patients. These burns are of particular concern because of their frequent localization to the hands, with the resulting negative implications for financial cost, long-term cosmesis, and hand function. A 5-year review of pediatric oven door burn cases admitted to a burn referral center was conducted. Of the 14 cases identified, the median age was 12 months. The median total body surface area (TBSA) was 1.75% (range, 0.5%-4.5%). Twelve of 14 cases involved 1 or both hands. The median length of hospital stay was 10 days. In 7 cases, burns were sustained from contact to an external surface of the oven. Based on the results obtained, we propose several prevention strategies.

Accidents, Home↗
PubMed2001

Prostaglandin E2 receptors EP2 and EP4 are down-regulated in human mononuclear cells after injury.

BACKGROUND: Recent characterization of prostaglandin receptor subtypes shows that each is critical to cellular functions and operates through separate signaling pathways that may explain differing effects of prostanoids. This study aimed to determine whether prostaglandin receptors EP2 and EP4 are modulated after injury and to evaluate the effect of prostaglandin E(2) (PGE(2)) addition and blockade on EP receptor expression. METHODS: Peripheral blood mononuclear cells (PBMCs) isolated from 10 patients sustaining fracture or burn injury and 10 control subjects were stimulated with lipopolysaccharide +/- NS-398, an inhibitor of PGE(2) production. Samples were evaluated for production of PGE(2), tumor necrosis factor--alpha, and leukotriene B(4) as well as mRNA expression of EP receptors and COX-2. EP receptor expression was also evaluated after treating control PBMCs with PGE(2). RESULTS: PBMCs from injured patients exhibited significant increases in PGE(2) production and COX-2 mRNA compared with control subjects, and these increases were inhibited by NS-398. In contrast, EP2 and EP4 receptors were markedly down-regulated after injury and NS-398 restored expression to control levels. Decreased EP2 and EP4 receptor expression after injury was replicated by coincubation of PBMCs with PGE(2). CONCLUSIONS: Specific PGE(2) receptors are down-regulated after injury and NS-398 reverses this response. Furthermore, PGE(2) mediates EP2 and EP4 down-regulation. These data suggest that specific EP receptor subtypes may provide critical targets for augmenting the immune response after injury in humans.

Adult↗
PubMed1996

The effects of burn blister fluid on cultured keratinocytes.

OBJECTIVE: Previous studies have suggested that burn blister fluid (BBF) may be detrimental to the healing of the underlying wound bed. In this study, the effects of burn blister fluid on cultured keratinocyte proliferation and differentiation were examined and quantitated using various techniques. METHODS: At three different concentrations (2%, 10%, 20% in 20% fetal bovine serum/complete culture medium), 19 BBFs were tested in triplicate using 12 populations of cultured keratinocytes. All BBFs were collected from partial thickness burns within 72 hours of injury,. BBF was added on day 4 of the keratinocyte culture. The effect on proliferation and viability was assessed using trypan blue dye exclusion. Multiparameter flow cytometric analysis was used to quantitate population kinetics and cell size distribution. Keratinocyte differentiation was determined using immunohistochemical staining of differentiation markers and quantitation of cornified envelope formation. RESULTS: Relative to control fluid, the BBF caused a variable effect on proliferation, ranging from 67% inhibition to 103% stimulation with an overall 4% inhibition. The range of keratinocyte viability was narrower, with a similar overall 4% reduction. Using flow cytometry to analyze RNA/DNA content and cell size, the BBF caused a subtle shift in keratinocyte population kinetics and cell size distribution toward larger, less rapidly dividing cells. The BBF had no significant effect on expression of the differentiation markers, filaggrin and involucrin. Finally, the BBF did not alter terminal differentiation as it did not influence formation of cornified envelopes (BBF = 9.1 +/- 4.8%, control = 9.9 +/- 6.6%). CONCLUSION: Previous biochemical analysis has shown that BBF consists primarily of human serum filtrate with locally produced acute reactants. Our study suggests that BBF is biologically similar to serum and does not significantly alter keratinocyte proliferation or differentiation in vitro.

Adolescent↗
PubMed1994

Identification and categorization of and cost for care of trauma patients: a study of 12 trauma centers and 43,219 statewide patients.

Medical and demographic data for trauma patients (n = 7120) admitted to 12 trauma centers in 1 year were reviewed. Data from New York State on all discharges for the same year (n = 2,535,501) were obtained and analyzed. Patients were identified as trauma patients based on NYC EMS trauma center advisory committee criteria translated into ICD-9-CM codes, and a computer-based algorithm was developed that identified 43,219 trauma patients. A standard resource cost (SRC) was also developed to compare relative cost among trauma and non-trauma patients in the same diagnosis-related groups (DRGs). The mean age of the 43,219 trauma patients was 43.1 years, 61.8% were male, the mean LOS was 13.4 days, the mean ISS was 10.4, and 61% were discharged from community hospitals. Trauma centers treated the more severely injured patients: mean ISSs were 12.3, 10.9, and 9.2 for level I, level II, and community hospitals, respectively. Payor mix varied by category, with 71% of penetrating trauma victims covered by Medicaid or self pay compared with 21% of blunt trauma victims. Level I centers treated twice as many self-pay and Medicaid patients as community hospitals. A comparison of relative cost showed that trauma patients cost 27.5 million dollars more than non-trauma patients in the same DRGs.

Adult↗
PubMed1992

The effect of elevated levels of thromboxane on host response to tumor.

Previous studies have demonstrated that human malignancies can synthesize large amounts of thromboxane. It has also been reported that thromboxane can significantly alter multiple components of physiologic and immunologic function. We investigated the effect of elevated levels of thromboxane on host response to tumor using multiple rat models, and the long acting thromboxane analogue U-46619. Administration of the thromboxane analogue was not found to significantly alter the growth of primary tumors or peritoneal metastases. The analogue was found to significantly decrease mean survival time with a pulmonary metastases model. The thromboxane analogue failed to alter macrophage cytotoxicity, lymphocyte cytotoxicity, T lymphocyte subset numbers, or lymphocyte blastogenic response. Administration of the thromboxane analogue decreased the rate of lymphocyte metabolism of glucose and decreased lymphocyte intracellular adenosine deaminase activity. In conclusion, elevated thromboxane levels do not appear to alter primary tumor growth or host immune function, but do decrease resistance to pulmonary metastases.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1992

Triage, initial assessment, and early treatment of the pediatric trauma patient.

It should be clear from this overview of triage, assessment, and initial care that early involvement by the leader of the trauma team is essential. Because operative intervention is so often necessary, the trauma team leader should be a surgeon with specialized training in trauma. The complex decision-making process involves prioritizing approaches by emergency room physicians, pediatricians, and surgical specialties in patients with multiple injuries. Even with single-system injury a rapid and logical approach to assessment and treatment is necessary in light of an overall longer term management plan.

Child↗
PubMed1992

Tolerance to endotoxin prevents mortality in infected thermal injury: association with attenuated cytokine responses.

Endotoxin, a lipopolysaccharide (LPS), is a bacterial cell wall product instrumental in producing deleterious host responses to infection. This LPS appears to act, in part, by triggering release of endogenous mediators such as cytokines. Repeated exposures to endotoxin produce attenuated responses to this molecule. To examine the mechanisms and biologic consequences of this tolerance to LPS, Wistar rats were subjected to a 14-day course of LPS administration. Tolerance to LPS with regard to anorexia, weight loss, and acute-phase responses was noted. Attenuation of these physiologic responses was accompanied by abrogation of circulating cytokine appearance in response to endotoxin, suggesting that tolerance to LPS is in part due to a decreased production of cytokines. Tolerance to LPS also diminished the response to a subsequent infected thermal injury, as measured by food intake, body weight, fibrinogen levels, and mortality. Thus, clinical conditions involving repeated exposure to LPS may modify the host's responses to subsequent injury. The attenuated responses to injury accompanying the decreased production of cytokines further implicate cytokines in the pathogenesis of injury and disease.

Acute-Phase Reaction↗
PubMed1992

Rectal prolapse after oral cathartics.

Complete rectal prolapse or procidentia is an uncommon condition long recognized but of uncertain pathogenesis. We report two patients, seen a decade apart, both of whom developed complete rectal prolapse after ingestion of oral cathartics in preparation for diagnostic studies. To our knowledge, cathartic-induced complete rectal prolapse has not been reported previously in the current medical literature, despite the thousands of bowel preparations performed annually. These two cases address the implications of such an occurrence, and we discuss the pertinent management issues.

Aged↗
PubMed1992

Multiple significant trauma diagnosis related groups: analysis and national projections based on the first year in an all-payor prospective payment system.

To assess the effect of diagnosis related group (DRG) changes on reimbursement for trauma care in New York State (NYS), 840 trauma patients were studied over a 2-year period. Average costs increased moderately ($10,338 vs. $11,646) while average revenues increased dramatically ($6,934 vs. $9,115), leading to a 21% reduction in operating losses ($1,310,625 vs. $1,032,733). This was largely a result of new multiple significant trauma (MST) DRGs. The impact of 1990/1991 DRG changes was assessed; a 39% reduction in operating losses occurred. Regression analysis of 1989 DRG case weight on cost indicated that MST DRGs were better predictors of resource utilization than other trauma DRGs. Review of NYS data affirmed that only 10% of trauma patients were assigned MST DRGs and 63% of trauma patients were discharged from community hospitals. On a national level, the effect of the new Medicare MST DRGs would be minimal, since only 5% of Medicare patients were assigned MST DRGs. Although improvements have been made, reimbursement for trauma care must be addressed further.

Adolescent↗
PubMed1991

Effect of prostaglandin E in multiple experimental models. VIII. Effect on host response to metastatic tumor.

Prostaglandin E (PGE) is produced by certain tumors and is reported to decrease primary tumor growth. We evaluated its effect in multiple tumor models utilizing a 1 week course of the long acting PGE derivative dimethyl-PGE (dPGE) at a dosage of 100 micrograms/kg/day vs. a lactated Ringers control. For all tumor models, a suspension of 1 x 10(6) colon carcinoma cells were injected into Wistar-Furth rats. When the suspension was injected subcutaneously and the drug was begun at the time of tumor challenge, there was no effect on survival. When the tumor was injected intraperitoneally or intravenously and the drug begun at the time of tumor challenge, dPGE decreased survival time. When the tumor was administered intravenously but dPGE was delayed for 5 days, there was no effect on survival time. When rats were given a 1 week course of dPGE or saline, dPGE was found not to alter natural killer (NK) cell cytotoxicity, macrophage cytotoxicity, spontaneous lymphocyte blastogenesis, or mitogen stimulated blastogenesis. dPGE failed to alter lymphocyte metabolism of glucose in nonstimulated lymphocytes, but decreased the rate of glucose metabolism and adenosine deaminase activity in mitogen stimulated lymphocytes. In conclusion, PGE appears to enhance metastatic growth of tumor lines where it does not alter primary tumor growth. This effect does not appear immunologically mediated.

Animals↗
PubMed1991

Increased neutrophil mobilization and decreased chemotaxis during cortisol and epinephrine infusions.

Although hormones are putative mediators of neutrophil changes after injury, the effects of trauma-induced levels of plasma cortisol and epinephrine on circulating neutrophils have not been reported in humans. The dynamics of PMN mobilization and chemotaxis were evaluated during 19 infusions of epinephrine or cortisol or a combined infusion of both hormones in ten normal volunteers. Basal levels of epinephrine and cortisol increased during infusions to levels consistent with those reported following severe injury. Circulating neutrophil counts increased in parallel with plasma cortisol levels. Epinephrine mobilized the entire marginated pool of neutrophils, and the neutrophil half-life was extended from a normal of 6.6 hours to 10.4 hours by cortisol. Chemotaxis after six hours of epinephrine infusion was reduced compared with baseline chemotaxis. In four volunteers who had a second infusion of cortisol, chemotaxis was significantly depressed ten days after the infusion compared with baseline. From these data we conclude that stress levels of epinephrine mobilize the marginated pool of granulocytes into the circulating pool in a linear fashion, and cortisol raises the half-life of circulating neutrophils. Reduced neutrophil chemotaxis seen as a consequence of these infusions could account for some of the increased susceptibility to infection that occurs after major trauma.

Chemotaxis, Leukocyte↗
PubMed1990

The effect of blood transfusions on immune function. V. The effect on the inflammatory response to bacterial infections.

Blood transfusions have been shown to be associated with increased bacterial infection rates in colon cancer patients and in multiple animal studies. This increased susceptibility appears due to impairments in the systemic resistance to infections and not to alterations in the local response. Specifically, transfusions in a rat model were not found to alter the peritoneal cavity's response to an Escherichia coli challenge or the burn wound's response to a Pseudomonas aeruginosa challenge. Transfusions did impair the macrophage's ability to phagocytose and kill bacteria. Transfusions also increased the serum level of the immunosuppressive glucocorticoid, corticosterone.

Analysis of Variance↗
PubMed1990

An all-payor prospective payment system (PPS) based on diagnosis-related-groups (DRG): financial impact on reimbursement for trauma care and approaches to minimizing loss.

To assess the financial impact of the new all-payor prospective payment system (PPS), data for 430 patients admitted to a Level I Trauma Center were compared to all hospital discharges (n = 35,309). Trauma patients had a LOS of 13.1 days, average Trauma Score of 15, and operating loss for trauma patients totalled $1,310,625. Trauma as compared to all patients showed a greater variance in LOS (6.3 vs. 2.0 days), a higher case mix index (CMI) (1.93 vs. 1.40), and a greater loss per case (-$3,404 vs. -$979), respectively. The trauma group DRG weights correlated with revenue (r = 0.89; p less than 0.0001); however, there was no relation to profit/loss. Review of trauma patients' records revealed inaccurate coding. Corrections led to an increase in reimbursement of $132,000. Five DRGs were added in 1989 for multiple significant trauma (MST). Using the 1989 grouper, 30 patients were reassigned, with an increase in reimbursement of $250,000. Although these strategies reduce operating deficit by 29%, reimbursement for trauma care must be addressed further.

Costs and Cost Analysis↗
PubMed1990

Elevated production of neutrophil leukotriene B4 precedes pulmonary failure in critically ill surgical patients.

Leukotriene B4, a potent neutrophil chemotactic factor, is also made by the neutrophil. Neutrophil function was studied in 12 patients at risk for the development of adult respiratory distress syndrome (ARDS) after admission to the surgical intensive care unit (ICU) to test the hypothesis that increased generation by the neutrophil generation of this mediator precedes the development of pulmonary failure. Peripheral blood neutrophils were tested for chemotaxis to f-met-leu-phe (fMLP) and leukotriene B4 (LTB4) and the generation of LTB4. Plasma was collected simultaneously for assay of C3a desArg levels. Five patients had ARDS a mean of 2.2 +/- 0.25 days after admission to the ICU. Neutrophil generation of LTB4 was significantly enhanced on ICU day 1 in these patients as compared with patients at risk for ARDS but not developing the syndrome (119.4 +/- 6.1 versus 101.0 +/- 5.1, per cent control, p less than 0.05). Chemotaxis to fMLP and LTB4 was significantly reduced in both groups of patients. However, neutrophil chemotaxis improved in patients who did not have pulmonary failure during the time in the ICU, whereas neutrophil chemotactic responsiveness worsened in patients who did have pulmonary failure. Plasma C3a desArg levels were significantly elevated over normal laboratory values on ICU day 1 in the ARDS patients (317.2 +/- 74.0 versus 132.0 +/- 16.0 milligrams per milliliter, p less than 0.01). These data indicate that LTB4 production by the neutrophil occurs concomitantly with complement activation, is a predictor of subsequent ARDS and may play a significant role in the development of pulmonary failure in critically ill surgical patients.

Chemotaxis, Leukocyte↗
PubMed1990

Effect of blood transfusions on immune function. Part VI. Effect on immunologic response to tumor.

Transfusions are reported to increase the incidence of tumor metastasis in clinical studies and primary tumor growth in animal studies. We evaluated the effect of transfusions on immunologic response to primary and metastatic tumors in multiple rat models. One half of the animals were administered lactated Ringer's solution and one half ACI rat blood at the time of tumor challenge. In 80 rats a slow-growing colon tumor was implanted subcutaneously. At 4 months there were no significant differences in tumor size or leukocyte infiltration of the tumor. Similar results were obtained with a rapidly growing colon cancer. Analysis of T-lymphocyte subpopulations in both groups showed no differences. Rats transfused at the time of intravenous challenge with a suspension of 1 x 10(6) tumor cells had a mean survival time of 38.3 +/- 0.8 days and the control group had a mean survival time of 41.1 +/- 0.8 days (p = 0.016). One week after transfusion, natural killer cell lysis of tumor cells at a 100:1 effector/target cell ratio was 18.0% +/- 1.8% in the transfusion group and 23.0% +/- 1.3% in the control group (p = 0.034). In conclusion, transfusions in multiple rat cancer models did not affect primary tumor growth or the host's immunologic response to it but did significantly impair natural killer cell function and survival with tumor metastases.

Adenocarcinoma↗
PubMed1989

Leukotriene B4 generation in patients with established pulmonary failure.

We investigated the cause of the reduced leukotriene B4 (LTB4) production seen in neutrophils from patients with established adult respiratory distress syndrome compared with control neutrophils. Lymphocytes/monocytes from controls were found to synergistically enhance the amount of LTB4 produced when incubated with neutrophils. This synergistic effect was not seen in cells from patients with adult respiratory distress syndrome. Fatty-acid analysis of neutrophils from patients with adult respiratory distress syndrome and controls showed remarkable similarity in all quantities of fatty acids measured except for arachidonic acid, where there was a 22% reduction in patients' cells compared with controls. Assay of the rate of generation of LTB4 and its degradation product, 20-hydroxy LTB4, revealed that reduced LTB4 generation in patients' neutrophils was not due to increased degradation of LTB4 by hydroxylase enzymes. When the amount of LTB4 being generated per milliliter of whole blood was analyzed in the patients with adult respiratory distress syndrome and compared with controls, it was determined that the potential to generate LTB4 in patients in the intensive care unit was three to five times greater than in controls.

Fatty Acids↗
PubMed1989

Hepatocellular membrane function during chronic burn injury.

Hepatocellular membrane dysfunction, as indicated by depolarization of the membrane potential, occurs after acute injury and early bacteremia. To determine whether hepatocellular membrane dysfunction occurs in the setting of ongoing thermal injury and infection, Wistar rats were divided into four groups: (1) sham-burned, freely fed controls (FF); (2) rats sustaining approximately 30% total body surface area dorsal full-thickness scald burn (Burn); (3) rats sustaining burns as in group 2 followed by immediate inoculation of 1 x 10(8) CFU Pseudomonas aeruginosa (Burn/Inf); and (4) sham-burned rats pair-fed to the food intake of the Burn/Inf group (PF). On the third and seventh days postburn, body and liver weights were determined. In vivo hepatocellular transmembrane potentials were measured and hepatic ATP, RNA, DNA, and protein contents were assayed. By Day 7, despite greater weight loss in the Burn/Inf group than due to starvation alone (P less than 0.01 Burn/Inf vs FF and PF), hepatic mass was conserved. This was associated with hyperpolarization of the hepatic transmembrane potential (-46.6 +/- 1.5 vs -32.1 +/- 0.6 mV, Burn/Inf vs FF, P less than 0.01) and increases in RNA (141 +/- 9 vs 91 +/- 4 mg/liver, Burn/Inf vs FF, P less than 0.01) and DNA (37 +/- 5 vs 22 +/- 2 mg/liver, Burn/Inf vs FF, P less than 0.05) contents, with no change in ATP or hepatic protein contents. There was a significant hypercorticosteronemia observed in the Burn/Inf group (43 +/- 9 vs 2.8 +/- 0.7 micrograms/dl, Burn/Inf vs FF, P less than 0.01). This hepatic membrane hyperpolarization and augmented RNA content were not secondary to burn or starvation alone as the response in these groups was significantly less than that of the Burn/Inf group. It is suggested that this hepatic membrane hyperpolarization is one mechanism by which hepatic function is maintained during ongoing burn infection in the rat.

Adenosine Triphosphate↗