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W H Marks

Publications and source records attributed to W H Marks.

At least 19 recordsLinked to original sources
PubMed2006

Report of a National Conference on Donation after cardiac death.

A national conference on organ donation after cardiac death (DCD) was convened to expand the practice of DCD in the continuum of quality end-of-life care. This national conference affirmed the ethical propriety of DCD as not violating the dead donor rule. Further, by new developments not previously reported, the conference resolved controversy regarding the period of circulatory cessation that determines death and allows administration of pre-recovery pharmacologic agents, it established conditions of DCD eligibility, it presented current data regarding the successful transplantation of organs from DCD, it proposed a new framework of data reporting regarding ischemic events, it made specific recommendations to agencies and organizations to remove barriers to DCD, it brought guidance regarding organ allocation and the process of informed consent and it set an action plan to address media issues. When a consensual decision is made to withdraw life support by the attending physician and patient or by the attending physician and a family member or surrogate (particularly in an intensive care unit), a routine opportunity for DCD should be available to honor the deceased donor's wishes in every donor service area (DSA) of the United States.

Adolescent↗
PubMed2006

Organ donation and utilization, 1995-2004: entering the collaborative era.

Continued progress in organ donation will help enable transplantation to alleviate the increasing incidence of end-stage organ disease. This article discusses the implementation and effect of the federally initiated Organ Donation Breakthrough Collaborative; it then reviews organ donation data, living and deceased, from 1995 to 2004. It is the first annual report of the Scientific Registry of Transplant Recipients to include national data following initiation of the collaborative in 2003. Prior to that, annual growth in deceased donation was 2%-4%; in 2004, after initiation of the collaborative, deceased donation increased 11%. Identification and dissemination of best practices for organ donation have emphasized new strategies for improved consent, including revised approaches to minority participation, timing of requests and team design. The number of organs recovered from donation after cardiac death (DCD) grew from 64 in 1995 to 391 in 2004. While efforts are ongoing to develop methodologies for identifying expanded criteria donors (ECD) for organs other than kidney, it is clear DCD and ECD raise questions regarding cost and recovery. The number of living donor organs increased from 3493 in 1995 to 7002 in 2004; data show trends toward more living unrelated donors and those providing non-directed donations.

Ethnicity↗
PubMed2001

Lack of utility of intestinal fatty acid binding protein levels in predicting intestinal allograft rejection.

INTRODUCTION: The enterocyte-specific protein, intestinal fatty acid binding protein (I-FABP), is detectable in serum only after intestinal injury. Previous studies in animals suggest that I-FABP might be a useful marker of intestinal allograft rejection. MATERIALS AND METHODS: I-FABP was repetitively measured in nine intestinal transplant recipients and correlated with findings of surveillance endoscopy. RESULTS: Average interval between I-FABP determination and biopsy was 3.4 days (SD=4.2 days). Average number of rejection episodes per patient totalled 1.6+/-1.2. General linear modeling demonstrated no tendency for increases in serum FABP to precede histologic graft rejection (P=0.263). Restriction of the analysis to I-FABP determinations 1 day before or on the day of biopsy failed to affect these results. Minor increases in I-FABP were often associated with histologically normal grafts, whereas rejection often occurred when I-FABP was not detectable. DISCUSSION: Serum I-FABP levels do not predict clinical intestinal allograft rejection.

Adult↗
PubMed2001

Elevated intestinal fatty acid binding protein and gastrointestinal complications following cardiopulmonary bypass: a preliminary analysis.

BACKGROUND: Cardiopulmonary bypass (CPB) is associated with poorly understood alterations in gastrointestinal (GI) perfusion. Intestinal fatty acid binding protein (IFABP), a cytosolic protein uniquely located in mature small-intestinal enterocytes, has been shown to be a sensitive biochemical marker of early intestinal ischemia when assayed in urine. We hypothesized that if significant small-intestinal ischemia occurs with CPB, then urine IFABP levels should be concomitantly elevated. METHODS: Twenty-nine patients (15 low risk and 14 high risk) undergoing cardiac surgery with CPB were studied prospectively. Serial urine IFABP levels were measured and results were correlated with clinical outcomes. RESULTS: None of the low-risk patients had IFABP elevations or experienced GI complications. Five of the high-risk patients had IFABP elevations, and three of the five developed GI complications. Within the high-risk cohort, the only significant difference between patients with or without IFABP elevations was the GI complication rate (P = 0.03). Overall, patients with IFABP elevations had a significantly higher mean ASA class and significant increases in mean CPB and aortic cross-clamp times, mean time to oral intake, median ICU and postoperative lengths of stay, and GI complications. CONCLUSIONS: In low-risk bypass patients, small-bowel mucosal perfusion appeared to be maintained, while in the high-risk population, 21% of the patients sustained clinically significant mucosal compromise. In this pilot study, urine IFABP was 100% sensitive and 92% specific with respect to GI complications. Since elevated urine IFABP concentrations appeared to correlate with clinical GI complications, urine IFABP may be a useful marker to identify the patient at risk for postbypass GI complications.

Aged↗
PubMed2000

Total warm ischemia and reperfusion impairs flow in all rat gut layers but increases leukocyte-vessel wall interactions in the submucosa only.

OBJECTIVE: To study the effect of warm ischemia and reperfusion (I/R) on local perfusion and leukocyte-vessel wall interactions in vivo in all small bowel layers, and to quantify small bowel tissue injury histologically and by measuring intestinal fatty acid binding protein (I-FABP) release from the enterocytes. SUMMARY BACKGROUND DATA: Gut injury as a result of I/R plays a pivotal role in a variety of clinical conditions, such as small bowel transplantation, heart or aortic surgery, and (septic) shock. The precise mechanism behind I/R injury and the role of microvascular changes remain unclear. The influence of warm I/R of the gut on microvascular parameters in the different gut layers has not been studied before. METHODS: Anesthetized Lewis rats were either subjected to 30 minutes of ischemia and 1 hour of reperfusion or sham-treated as controls. After ligating the inferior mesenteric artery, total warm ischemia was induced by clamping the superior mesenteric artery. Intravital video microscopic measurements were obtained at intervals. Tissue injury of the small bowel and other organs was histologically evaluated afterward. In addition, plasma levels of I-FABP were determined to measure enterocyte damage. RESULTS: After ischemia, mean red blood cell velocity decreased significantly in all layers of the small bowel, but no diameter changes were observed. Leukocyte-vessel wall interactions increased in the submucosa but not in the muscle layers. Plasma levels of I-FABP significantly increased from 30 minutes of reperfusion onward. The intestinal mucosa was severely injured; no histologic damage was detected in other tissues. CONCLUSIONS: This is the first in vivo study showing that total warm ischemia of the rat gut impairs perfusion in the whole small bowel, whereas leukocyte-vessel wall interactions increase in the submucosal layer only. Therefore, the early inflammatory response to I/R seems to be limited to the submucosa. Both microvascular effects may have contributed to the severe morphologic and functional mucosal injury observed after I/R.

Animals↗
PubMed1999

Plasma intestinal fatty acid binding protein in neonates with necrotizing enterocolitis: a pilot study.

BACKGROUND/PURPOSE: Intestinal fatty acid-binding protein (IFABP) is found within cells at the tip of the intestinal villi, an area commonly injured when necrotizing enterocolitis (NEC) occurs. This study was undertaken to determine if measuring IFABP concentrations in the bloodstream early in the course of NEC would differentiate patients by severity before clinical findings made it clear who had stage 3 NEC and who had milder stages. METHODS: Three plasma samples from newborn infants evaluated for NEC were obtained at symptom onset and after 8 and 24 hours. IFABP concentration was measured by radioimmunoassay. Infants were classified by the final and most severe stage of NEC, and IFABP levels were compared between groups at each sampling. RESULTS: IFABP was detectable in blood samples from all 7 infants with stage 3 NEC compared with 3 of 24 with stages 1 or 2 NEC. Elevated plasma IFABP concentrations were detectable before clinical staging could be made in 5 of the 7 subjects with stage 3 NEC. CONCLUSION: IFABP may be a specific marker for early identification of severe NEC.

Biomarkers↗
PubMed1999

Intestinal mucosal injury in critically ill surgical patients: preliminary observations.

This was a prospective study designed to evaluate the extent to which intestinal mucosal compromise occurs in adult critical care patients with and without systemic inflammatory response syndrome (SIRS) and to correlate the degree of intestinal injury with outcome. Ten patients from a university hospital surgical intensive care unit were identified who manifested SIRS at the time of admission to the intensive care unit. Five other critical care patients without SIRS were also evaluated. The Acute Physiology and Chronic Health Evaluation II score was determined. Intestinal mucosal viability was assessed by serial measurement of serum and urine iFABP intestinal fatty acid binding protein (iFABP), a sensitive and specific marker for mucosal injury. Outcome in terms of the development of multiorgan dysfunction syndrome, adult respiratory distress syndrome, and survival was determined. iFABP was detectable in the serum or urine in 8 out of 10 patients with SIRS. Among the 4 patients with detectable serum iFABP, 2 died and 1 developed severe adult respiratory distress syndrome. Nine of 11 patients without detectable serum iFABP recovered without major morbidity. iFABP was detectable in most patients with SIRS, suggesting that subclinical intestinal mucosal compromise is a frequent component of this syndrome. When iFABP was detectable, particularly in the serum, the prognosis was poor, even in the absence of SIRS, indicating that iFABP may be a relevant and independent predictor of outcome in critical care patients.

Adolescent↗
PubMed1998

Organ failure, infection, and the systemic inflammatory response syndrome are associated with elevated levels of urinary intestinal fatty acid binding protein: study of 100 consecutive patients in a surgical intensive care unit.

BACKGROUND: Intestinal mucosal ischemia and subsequent barrier dysfunction have been related to the development of organ dysfunction and death in the critically ill. We hypothesized that urine concentrations of intestinal fatty acid binding protein (IFABP), a sensitive marker of intestinal ischemia, might predict the development of the systemic inflammatory response syndrome (SIRS) and organ dysfunction. METHODS: One hundred consecutive critically ill patients were prospectively studied for the development of infectious complications, organ dysfunction, and SIRS. Urine was collected daily for measurement of IFABP. RESULTS: A total of 58 males and 42 females (mean age, 56 years; range,16-85 years) were studied. Of these 100 patients, 40 patients developed complications and 5 patients developed SIRS. IFABP was significantly elevated in all patients with SIRS, and IFABP levels peaked an average of 1.4 days (range, 0-7 days) before the diagnosis of SIRS. CONCLUSION: Elevated concentrations of urine IFABP correlated with the clinical development of SIRS. Studies to assess the utility of IFABP as a predictor of organ dysfunction and SIRS in the critically ill are warranted.

Adolescent↗
PubMed1997

Asialoglycoprotein/asialoglycoprotein receptor (AGP-AGPr) interaction is an important mechanism for the uptake of FK506 by hepatocytes.

Hepatic tissue concentrations of FK506 have been correlated with early acute rejection following liver transplantation. Asialoglycoproteins (AGP) reputedly bind FK506 in blood. AGP are removed from the circulation by the liver via the AGP receptor (AGPr), which resides on hepatocytes. This study was undertaken to determine if the AGP-AGPr mechanism enhances the delivery of FK506 to hepatocytes. Human orosomucoid (OM) was used as a representative AGP. asialoOM (aOM) was prepared by desialation of OM. Fresh rat hepatocytes were isolated by collagenase digestion. Tritium labeled FK506 (FK) was used to identify and quantitate FK506. Quantitation of FK in serum and culture media was by direct counting. FK in animal tissues used a method developed in our laboratory for the purpose. AGPr on resting hepatocytes was demonstrated by flow cytometry using FITC-orosomucoid and FITC-BSA controls. AGPr were enhanced by 2 g glucose/L. Two serum FK-binding fractions, 44 kD and 15 kD, were identified by gel filtration. Exogenous OM avidly bound FK and displaced FK activity from the 15 kD fraction. Serum (1%) and the 44 kD fraction enhanced the uptake of FK by hepatocytes, while serum depleted of OM-aOM by affinity chromatography was only 72.5% as effective as control serum; aOM enhanced the uptake of FK by hepatocytes to a degree similar to that of control serum but OM did not significantly affect the uptake of FK. Cold FK506 blocked the uptake and was dose dependent; cold CsA had no effect. Affinity extraction of OM from serum to which FK had previously been added removed 28.4% of FK activity. Following i.v. infusion, the kidney had the highest and liver the lowest tissue concentration of FK at 1 hr and 3 hr. In contrast, after oral administration the liver had the highest concentrations of the other tissues tested. The AGP-AGPr mechanism plays a significant role in the delivery of FK506 to hepatocytes and is likely responsible for the differences in bioavailability observed after oral and i.v. administration. Factors governing the AGP-AGPr mechanism are germane to understanding both the efficacy and toxicity of FK506 and the development optimal therapeutic strategies.

Administration, Oral↗
PubMed1997

Human intestinal fatty acid binding protein: report of an assay with studies in normal volunteers and intestinal ischemia.

BACKGROUND: Human intestinal fatty acid binding protein (hIFABP) is a cytoplasmic protein of mature small intestinal epithelium. Work with the rat demonstrated that serum levels of IFABP correlated with early phases of intestinal mucosal injury. The aim of this study was to develop an assay for hIFABP and assess its usefulness as a marker for intestinal mucosal injury in human beings. METHODS: Recombinant hIFABP (r-hIFABP) was used to produce rabbit anti-hIFABP. Specificity and avidity of binding were tested with immunoprecipitation and Scatchard analysis. r-hIFABP was labeled with 125I, and a competitive assay was developed. Urine and serum from normal volunteers and from patients with necrotizing enterocolitis (NEC), acute thromboembolic related intestinal ischemia, and systemic inflammatory response syndrome were tested for hIFABP. RESULTS: Molecular weight was 10(-12) kd, limit of detection was 1.87 ng/ml, and no cross-reactivity occurred when tested against rat IFABP or human heart FABP. Mean levels of hIFABP (ng/ml) were controls (serum less than 1.87, urine less than 1.87), NEC (serum 14.7 ng/ml), intestinal ischemia (serum 50 ng/ml, urine 52.3 ng/ml), systemic inflammatory response syndrome (serum 5.3 ng/ml, urine 13.2 ng/ml). CONCLUSIONS: This assay is quantitative for hIFABP in serum and urine. Results from both normal persons and those with various causes of intestinal ischemia parallel our previous findings in the rat. Preliminary findings suggest that hIFABP may serve as a diagnostic marker for early intestinal mucosal compromise and, in addition, that it should prove useful as a tool in developing rationale therapeutic regimens to treat these complex clinical problems.

Adolescent↗
PubMed1996

Successfully treated invasive pulmonary aspergillosis associated with smoking marijuana in a renal transplant recipient.

Invasive pulmonary aspergillosis (IPA) is often a lethal entity in transplant recipients (up to 90%). We report the successful treatment of a case of IPA in a renal transplant recipient whose only risk for exposure was habitual marijuana smoking. Although marijuana smoking has been linked to the development of IPA in patients immunosuppressed for a variety of reasons, this case is the first report involving a solid organ transplant recipient. The patient's clinical course and treatment are described and the literature is reviewed with respect to environmental and patient risk factors. In this case, IPA was associated with the patient's heavy usage of marijuana during the immediate posttransplant period. Treatment was successful and included the experimental amphotericin product amphotericin B colloidal dispersion. Contemporaneous exposure to a large amount of inocula of Aspergillus within 30 days of receiving high doses of steroids appeared to be the most important factor that predisposed this patient to IPA. Transplant recipients should be specifically proscribed from marijuana use during periods of high steroid administration.

Antifungal Agents↗
PubMed1996

Small bowel allograft rejection detected by serum intestinal fatty acid-binding protein is reversible.

We hypothesized that, following experimental small bowel transplantation, immunosuppressive therapy initiated on the day of the initial rise in serum intestinal fatty acid-binding protein (I-FABP) would result in graft salvage. In previously published work, we showed that I-FABP was not detectable in the serum of isografted Lewis rats, but could be measured in the peripheral circulation during small bowel allograft rejection. A clinically useful method to monitor trans- planted allografts for rejection should detect the problem early in its evolution so that treatment to reverse the process would salvage a functional organ. Lewis rats served as recipients of LBNF1 out-of-continuity small bowel allografts and were studied in two groups: group I (control) received no immunosuppression and group II received cyclosporine (CsA, 15 mg/kg/d, p.o.) when I-FABP rose to > or = 80 ng/ml. Serum I-FABP was measured daily until the time of sacrifice. Full-thickness graft biopsies were obtained on postoperative days 3 (baseline), 6 or 7 (elevated I-FABP), 10, and 14 (sacrifice). Following transplantation baseline serum I-FABP (day 2 or 3) averaged < or = 10.0 ng/ml. I-FABP remained at baseline through day 5 (range 0-50 ng/ml) in all animals and then rose abruptly on either day 6 or 7 (range 86-150 ng/ml; P < 0.001 vs. baseline). Histology on day 6 or 7 revealed a mild-to-moderate cellular rejection. Cyclosporine therapy reversed the rejection reaction and restored the bowel to normal histology. Serum I-FABP returned to baseline. In untreated animals, serum I-FABP remained elevated for several days and then returned to baseline levels coincident with fulminant rejection and mucosal sloughing. I-FABP was released into the peripheral circulation early in the evolution of acute rejection in this model of small bowel transplantation. Immunosuppressive therapy initiated when elevated levels of I-FABP were detected in the serum resulted in graft salvage. Cyclosporine immunotherapy consistently reversed rejection in this model. This article represents the first report of salvage of small bowel allografts when immunosuppressive therapy was instituted prospectively on the basis of a serum marker. Immunoreactive I-FABP appears to hold significant potential as a biochemical screening tool for acute rejection occurring In small bowell allografts.

Animals↗
PubMed1996

Human syngeneic intestinal transplantation: evaluation of enterocyte viability with serum levels of intestinal fatty acid binding protein.

In a case of human syngeneic intestinal transplantation, the post-operative course was complicated by the Systemic Inflammatory Response System (SIRS). This syndrome was characterized by negative cultures and elevated levels of the pro-inflammatory cytokines, IL-1 beta, IL-6 and TNF. In keeping with current concepts of translocation across the enterocyte barrier as the etiology of SIRS, levels of intestinal fatty acid binding protein (I-FABP), an enterocyte-specific protein, also increased. These observations suggest that (i) a clinical syndrome consistent with translocation may occur in the absence of rejection in intestinal transplantation, and (ii) I-FABP may serve as a clinically relevant marker for enterocyte injury.

Adult↗
PubMed1993

Elevation of circulating intestinal fatty acid binding protein in a luminal contents-initiated model of NEC.

Necrotizing enterocolitis (NEC) continues to produce significant morbidity and mortality, due in part to the difficulty in detecting its initial manifestations at a stage when compromised intestine may potentially be salvaged. We have previously reported our findings that intestinal fatty acid binding protein (I-FABP) is a sensitive biochemical marker for early intestinal mucosal injury due to mesenteric ischemia. In this study we evaluated the potential of serum I-FABP as a marker for incipient NEC in a nonischemic model of NEC in the rat. Intraluminal instillation of a solution of casein (10 mg/mL) and calcium gluconate (50 mg/mL) in saline acidified to pH 4.0 with propionic acid resulted in a rapid and prolonged increase in serum I-FABP from a baseline of < or = 4.0 ng/mL to 171 +/- 40 ng/mL. Instillation of the same electrolyte solution with either casein or propionic acid alone resulted in a less dramatic elevation of serum I-FABP to 19 +/- 4 ng/mL and 76 +/- 30 ng/mL, respectively. In both cases baseline values of < or = 4.0 ng/mL were reached within 60 minutes. In control animals, which received saline alone, serum I-FABP was undetectable throughout the experiment. Simultaneously, we found that serum hexosaminidase, a putative biochemical marker for intestinal ischemia and NEC, was unchanged in all groups. Light microscopy of the intestinal specimens obtained three hours after instillation of casein and organic acid demonstrated superficial villus necrosis and villus blunting, but no areas of transmural necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Hepatic retransplantation in New England--a regional experience and survival model.

Hepatic retransplantation (reTx) offers the only alternative to death for patients who have failed primary hepatic transplantation (PTx). Assuming a finite number of donor organs, reTx also denies the chance of survival for some patients awaiting PTx. The impact of reTx on overall survival (i.e., the survival of all candidates for transplantation) must therefore be clarified. Between 1983 and 1991, 651 patients from the New England Organ Bank underwent liver transplantation, and 73 reTx were performed in 71 patients (11% reTx rate). The 1-year actuarial survival for reTx (48%) was significantly less than for PTx (70%, P < 0.05). This survival varied, dependent on the interval of time following PTx in which the reTx was performed (0-3 days, 57% survival; 4-30 days, 24%; 30-365 days, 54%; and > 365 days, 83%). Patients on the regional waiting list had an 18% mortality rate while awaiting transplantation. These results were incorporated into a mathematical model describing survival as a function of reTx rate, assuming a limited supply of donor livers. ReTx improves the 1-year survival rate for patients undergoing PTx but decreases overall survival (survival of all candidates) for liver transplantation. In the current era of persistently insufficient donor numbers, strategies based on minimizing the use of reTx, especially in the case of patients in whom chances of success are minimal, will result in the best overall rate of patient survival.

Adolescent↗