Diaspirin cross-linked hemoglobin resuscitation of hemorrhage: comparison of a blood substitute with hypertonic saline and isotonic saline

Resuscitation with tiny volumes of hypertonic solutions rapidly restores tissue perfusion while minimizing edema after hemorrhage and tissue trauma.

METHODS

We compared an O2-carrying fluid, Diaspirin Cross-Linked Hemoglobin (DCLHb), to 7.5% NS/Dextran-70 (HTS) or 0.9% saline (NS) in a trauma (celiotomy) hemorrhage model. Anesthetized rats (n = 10/group) underwent a tracheotomy, placement of jugular vein and carotid artery catheters, and placement of an abdominal aortic flow probe. Rats were hemorrhaged (20 mL/kg) from t = 0-15 minutes, and were given NS (group I), 60 mL/kg, HTS (group II), 4 mL/kg, or DCLHb (group III), 4 mL/kg, from t = 15-30 minutes. Sampling mandated removal of an additional 10 mL/kg of blood during the 2-hour experiment.

RESULTS

Mean arterial pressure was restored after hemorrhage in all groups. Oxygen delivery, which diminished dramatically after hemorrhage, was less than baseline in all groups after resuscitation. Oxygen consumption was restored in all groups after a sharp decrease during hemorrhage. Base deficit increased in the all groups but was greatest after normal saline or hypertonic saline resuscitation (t = 120 minutes; I = 12 +/- 0.4*, II = 13 +/- 0.5* c, III = 10 +/- 0.1*; * = p < 0.05 versus baseline value within group for groups I, II, and III; c = p < 0.05 group versus DCLHb (group II), by ANOVA).

CONCLUSION

DCLHb restored mean arterial pressure and ameliorated the development of flow-dependent oxygen consumption. Base deficit, a reflection of systemic oxygen debt, was minimized with this blood substitute. DCLHb may represent a superior small volume resuscitative fluid after trauma and hemorrhage.

Maxillary sinusitis in the surgical intensive care unit: a study using bedside sinus ultrasound

PURPOSE

This study investigates the incidence of acute maxillary sinusitis (AMS) in the surgical intensive care unit (SICU).

METHODS

One hundred consecutive patients admitted to the SICU were examined in a prospective observational mode. Bedside sinus ultrasound (SUS) was performed on admission and every 48 hours. Patients with sinus fluid by SUS and unexplained sepsis underwent confirmatory sinus aspiration.

RESULTS

The development of fluid in the maxillary sinus was identified in 15 patients by SUS. Acute maxillary sinus occurred in only 1 (1%).

CONCLUSION

This study shows SUS to be a simple, efficient method for determining the presence of maxillary sinus fluid in the SICU. Acute maxillary sinus was an unusual finding. Our policy of avoidance of nasal instrumentation may have contributed to the low incidence of AMS in this high-risk patient population.

Immunoglobulin variable region usage in human intestinal B lymphocytes

The B cell repertoire was studied in intestinal mononuclear cells from normal individuals and patients with inflammatory bowel disease (IBD) by examining Ig heavy chain variable gene (VH) usage. Using reverse transcription of intestinal mucosal RNA followed by polymerase chain reaction with primers specific for each VH family and a housekeeping gene, a semiquantitative assay of VH family content in RNA samples was developed. While all VH family members were expressed, differences in VH usage in lamina propria intestinal B cells were noted between Crohn's disease, ulcerative colitis, and normal individuals. mRNA transcripts for VH4 were present at seemingly higher levels than their genomic representation and transcripts for VH1 and VH4 appeared to have higher levels in active, compared to inactive, IBD. Thus, within the massive polyclonal intestinal B cell response, there is a skewed VH usage which may be relevant to the antigenic and/or autoimmune response noted in IBD.

Detection of aortic tear in the acute trauma patient using MRI

Traumatic aortic tears are life threatening and, therefore, need to be evaluated urgently. Typically, a thoracic aortogram is conducted; however, aortography occasionally demonstrates nonspecific abnormalities. These equivocal examinations can lead to unnecessary thoracotomies, or repeated angiography and catastrophic delays in aortic repair. We report a case in which magnetic resonance (MR) imaging was very useful in the diagnosis of aortic tear.

In vitro comparison of heated saline-blood admixture with a heat exchanger for rapid warming of red blood cells

We compared the rapidity of rewarming and infusing red blood cells (RBCs) mixed with 24 degrees C, 50 degrees C, and 60 degrees C saline with the rapidity of administering undiluted RBCs through a heat exchanger. We measured flow rate, final temperature, and hemolysis in matched 41-45-day-old pooled AS-1 RBCs infused through high-flow tubing via a 14-gauge catheter under the influence of gravity. Undiluted RBCs were tested as controls. The final temperature of the 60 degrees C admixture technique was lower than that with the heat exchanger (28.5 +/- 0.2 degrees C vs. 32.7 +/- 0.2 degrees C), but the flow rate was higher (258 +/- 8 mL/min vs. 61 +/- 4 mL/min). Admixture with 60 degrees C saline resulted in no increase in hemolysis. This technique appears to be a simple, inexpensive method for rapid rewarming and infusion of RBCs and may be valuable for administration of RBCs simultaneously through multiple sites during resuscitation.

Prospective ultrasound evaluation of venous thrombosis in high-risk trauma patients

To determine the incidence of venous thrombosis (VT), high-risk trauma patients were evaluated prospectively biweekly with Doppler ultrasound (US). Fifty-seven patients during an 8-month period met high-risk criteria for VT including age > 45 years, > 2 days bed rest, previous history of thromboembolism, spine fracture, coma, spinal cord injury, pelvic fracture, lower extremity injury, or femoral vein catheter. Doppler ultrasound showed 16 VTs in 12 patients. Venous thrombosis occurred despite prophylaxis (heparin or compression devices) in 9 of 12 patients. Iliac VT was noted in four patients, two of whom had no lower extremity VT. Upper extremity VT occurred in two patients who had received central venous catheters.

CONCLUSIONS

(1) US surveillance may be valuable in high-risk trauma patients because VT is a common finding (21%), despite prophylactic measures. (2) Examination of the upper extremity and pelvic venous system appears to be important, since 33% (4 of 12) of our patients with VT developed thrombi isolated to these regions. These would not have been identified during routine lower extremity duplex studies.

Comparison of MRI with postcontrast CT for the evaluation of acute abdominal trauma

We compared the ability of MRI and CT to detect and characterize abdominal visceral injury. Seven patients with contrast-enhanced abdominal CT interpreted as showing definite (five patients) or possible (two) solid organ injury following blunt abdominal trauma were referred for abdominal MRI with a mean interval of 3 days between modalities. T1-weighted and T2-weighted spin echo sequences were obtained in all patients. Gradient-recalled echo (GRE) sequences (22-25/12-13/60 degrees flip angle) were obtained in five cases. Both CT and MR allowed detection of complex splenic lacerations in two patients and complex hepatic injuries in three other patients. A sixth patient had subtle periportal hypodensity noted on CT which was not detected prospectively on MRI. One patient had a right adrenal hematoma detected on MRI but not on CT. Relative lesion conspicuity and extent were judged equal on CT and T2-weighted imaging. The T1-weighted and GRE imaging were judged inferior to CT. We conclude that MRI offers no significant advantage over CT for the routine evaluation of acute abdominal trauma.

Use of transgenic mice to map cis-acting elements in the intestinal fatty acid binding protein gene (Fabpi) that control its cell lineage-specific and regional patterns of expression along the duodenal-colonic and crypt-villus axes of the gut epithelium

The mouse intestinal epithelium is able to establish and maintain complex lineage-specific, spatial, and temporal patterns of gene expression despite its rapid and continuous renewal. A multipotent stem cell located near the base of each intestinal crypt gives rise to progeny which undergo amplification and allocation to either enterocytic, Paneth cell, goblet cell, or enteroendocrine cell lineages. Differentiation of these four lineages occurs during their geographically ordered migration along the crypt-villus axis. Gut stem cells appear to have a "positional address" which is manifested by differences in the differentiation programs of their lineal descendants along the duodenal-colonic (cephalocaudal) axis. We have used the intestinal fatty acid binding protein gene (Fabpi) as a model to identify cis-acting elements which regulate cell- and region-specific patterns of gene expression in the gut. Nucleotides -1178 to +28 of rat Fabpi direct a pattern of expression of a reporter (human growth hormone [hGH]) which mimics that of mouse Fabpi (a) steady-state levels of hGH mRNA are highest in the distal jejunum of adult transgenic mice and fall progressively toward both the duodenum and the mid-colon; and (b) hGH is confined to the enterocytic lineage and first appears as postmitotic, differentiating cells exit the crypt and migrate to the base of small intestinal villi or their colonic homologs, the surface epithelial cuffs. Nucleotides -103 to +28, which are highly conserved in rat, mouse and human Fabpi, are able to correctly initiate transgene expression in late fetal life, restrict hGH to the enterocytic lineage, and establish an appropriate cephalocaudal gradient of reporter expression. This cephalocaudal gradient is also influenced by cis-acting elements located between nucleotides -1178 and -278, and -277 and -185 that enhance and suppress (respectively) expression in the ileum and colon and by element(s) located upstream of nucleotide -277 that are needed to sustain high levels of hGH production after weaning. Nucleotides -277 to -185 contain part of a domain conserved between the three orthologous Fabpi genes (nucleotides -240 to -159), a 24-bp element (nucleotides -212 to -188) that binds nuclear factors present in colonic but not small intestinal epithelial cells, and a portion of a CCAAT/enhancer binding protein footprint (C/EBP alpha, nucleotides -188 to -167). Removal of nucleotides -277 to -185 (yielding I-FABP-184 to +28/hGH+3) results in inappropriate expression of hGH in proliferating and nonproliferating epithelial cells located in the mid and upper portions of duodenal, jejunal, ileal, and colonic crypts without affecting the "shape" of the cephalocaudal gradient of transgene expression.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of gene expression in gastric epithelial cell populations of fetal, neonatal, and adult transgenic mice

Little is known about lineage relationships and differentiation programs of various epithelial cells present in mouse gastric units. We have previously used rat liver fatty acid binding protein/human growth hormone (L-FABP/hGH) transgenes to define epithelial cell lineages relationships in the small intestine of fetal and adult mice and to examine regulation of their terminal differentiation programs along the crypt-to-villus and duodenal-to-ileal axes. We have now used these transgenes to explore similar issues in the stomach. Immunocytochemical studies of fetal and adult transgenic L-FABP/hGH animals and their normal littermates revealed that the intact endogenous mouse L-FABP gene (Fabpl) is not expressed in gastric epithelium. Nucleotides-596 to +21 of the rat L-FABP gene direct "inappropriate" expression of hGH in the gastric epithelium as early as fetal day 15. From 1 to 13 mo, L-FABP-596 to +21/hGH expression occurs only in surface mucous cells of zymogenic and mucous gastric units; the reporter is not detectable in the enteroendocrine, parietal and chief cell populations of zymogenic glands. Electron microscopic immunocytochemistry revealed that hGH is directed to apical secretory granules in surface and pit mucous cells expressing the transgene. hGH levels vary widely among surface mucous cells both within single pits and between gastric units in a given animal. The heterogeneity noted in reporter expression suggests that there are marked differences in the regulatory environments of individual cells of a single type within a given gastric unit. This raises the possibility that cell differentiation programs in the stomach may not be as tightly coupled to cellular translocation as in the small intestine. Finally, the lack of expression of L-FABP-596 to +21/hGH in gastrin- and serotonin-immunoreactive cells of the stomach contrasts with its efficient expression in comparable cell types located in the duodenum; providing a model system for examining differential regulation of gene expression in terminally differentiated cell types represented in both gastric and intestinal epithelium.

Expression of SV-40 T antigen in the small intestinal epithelium of transgenic mice results in proliferative changes in the crypt and reentry of villus-associated enterocytes into the cell cycle but has no apparent effect on cellular differentiation programs and does not cause neoplastic transformation

The mouse intestinal epithelium represents a unique mammalian system for examining the relationship between cell division, commitment, and differentiation. Proliferation and differentiation are rapid, perpetual, and spatially well-organized processes that occur along the crypt-to-villus axis and involve clearly defined cell lineages derived from a common multipotent stem cell located near the base of each crypt. Nucleotides -1178 to +28 of the rat intestinal fatty acid binding protein gene were used to establish three pedigrees of transgenic mice that expressed SV-40 large T antigen (TAg) in epithelial cells situated in the uppermost portion of small intestinal crypts and in already committed, differentiating enterocytes as they exited these crypts and migrated up the villus. T antigen production was associated with increases in crypt cell proliferation but had no apparent effect on commitment to differentiate along enterocytic, enteroendocrine, or Paneth cell lineages. Single- and multilabel- immunocytochemical studies plus RNA blot hybridization analyses suggested that the differentiation programs of these lineages were similar in transgenic mice and their normal littermates. This included enterocytes which, based on the pattern of [3H]thymidine and 5-bromo-2'- deoxyuridine labeling and proliferating nuclear antigen expression, had reentered the cell cycle during their migration up the villus. The state of cellular differentiation and/or TAg production appeared to affect the nature of the cell cycle; analysis of the ratio of S-phase to M-phase cells (collected by metaphase arrest with vincristine) and of the intensities of labeling of nuclei by [3H]thymidine indicated that the duration of S phase was longer in differentiating, villus- associated enterocytes than in the less well-differentiated crypt epithelial cell population and that there may be a block at the G2/M boundary. Sustained increases in crypt and villus epithelial cell proliferation over a 9-mo period were not associated with the development of gut neoplasms--suggesting that tumorigenesis in the intestine may require that the initiated cell have many of the properties of the gut stem cell including functional anchorage.

The mouse intestinal fatty acid binding protein gene: nucleotide sequence, pattern of developmental and regional expression, and proposed structure of its protein product

The rat intestinal fatty acid binding protein (I-FABP) gene has been used as a model to study temporal and spatial differentiation of the gut epithelium while its protein product has been used as a model for examining the atomic details of noncovalent fatty acid-protein interactions. We have isolated the mouse I-FABP gene (Fabpi) and determined its nucleotide sequence. Comparisons of the orthologous mouse, rat, and human I-FABP genes revealed three conserved domains in their otherwise divergent 5' nontranscribed sequences. RNA blot hybridization and multilabel immunocytochemical methods were used to compare the developmental stage-specific patterns of activation of the rat and mouse genes. In addition, Fabpi expression in enterocytes was examined as a function of their differentiation along the crypto-to-villus and duodenal-to-colonic axes of the small intestine. Based on the similar temporal and geographic patterns of mouse and rat I-FABP expression described here and the results of our earlier studies of transgenic mice containing rat Fabpi/human growth hormone fusion genes, we propose that one of the conserved domains, spanning nucleotides -500 to -419 in mouse Fabpi, and/or a 14-bp element, are necessary for establishing and maintaining its region-specific expression along the duodenal-to-colonic axis of the perpetually renewing gut epithelium. Finally, predictions of the structure of mouse I-FABP using the refined 2.0 A model of rat I-FABP, suggest that a proline found at position 69 of the mouse, but not rat, protein may affect its ligand binding properties.

Exclusion of cervical spine injury: a prospective study

Trauma room lateral cervical spine radiographs (LCSR) may improve the safety of intubation and transportation of multiply injured patients by providing earlier recognition of spinal vertebral injuries. We prospectively evaluated 60 consecutive trauma admissions to determine the impact of clearance of cervical spine radiographs on patient care. Fifty-three patients had no cervical spine injury (CSI). Intubations, emergency head CT scan, aortography, or urgent operation (less than 6 hours after admission) were required in the majority of patients and preceded complete cervical spine clearance in all but one instance. The median time for radiologic clearance of the cervical spine was 15 hours (range, 1.5 to 181). LCSR failed to identify three of the seven acute CSI (all three had C7 fractures). The spine-injured were managed with cervical collars and no new neurologic injury developed. We conclude that: 1) LCSRs do not appear to alter urgent management of multiply injured patients during resuscitation and transportation; 2) chest radiographs and emergency investigations should not be delayed by repeated LCSR in the trauma room as it may be difficult to fully exclude CSI in many trauma patients; 3) we support the current ATLS guidelines, which suggest that all patients should be presumed to have an unstable CSI until the presence of cervical injury has been excluded.

Leukotriene C4 induces mesenteric hypoperfusion and intestinal intramural acidosis in pigs

We examined the effect of intravenous infusion of graded doses of authentic leukotriene (LT) C4 on several physiological variables in pentobarbital-anesthetized immature swine. Mesenteric blood flow (Qsma) was measured using an ultrasonic flow probe and ileal intramucosal hydrogen ion concentration ([H+]I) was estimated tonometrically. Three groups were studied. Pigs in Group I (n = 6) were infused beginning at t = 0 min with increasing doses (0.03-1.0 microgram/kg-min) of LTC4, each dose being administered for 10 min. Pigs in Group II (n = 6) were infused with LTC4 as above, but were pre- and post-treated with a specific sulfidopeptide LT receptor antagonist, LY203647 (30 mg/kg bolus and then 10 mg/kg-hr) beginning at t = -20 min. Pigs in Group III (n = 4) received only normal saline (5 ml/kg-h). Infusing LTC4 significantly decreased Qsma and mesenteric oxygen uptake and significantly increased ileal [H+]I. These changes were prevented by LY203647. These data support the idea that sulfido-peptide LT are capable of causing mesenteric ischemia and that this phenomenon can be blocked by LY203647.

Beneficial effects of LY203647, a novel leukotriene C4/D4 antagonist, on pulmonary function and mesenteric perfusion in a porcine model of endotoxic shock and ARDS

The sulfidopeptide leukotrienes (LT) have been implicated as important pathophysiological mediators in septic shock. To further define the role of these compounds, we utilized a porcine endotoxicosis model to study the effects of pre- and concurrent treatment with LY203647, a novel LT receptor antagonist. Pentobarbital-anesthetized pigs (13-20 kg) were mechanically ventilated with 100% O2. Superior mesenteric arterial flow (Qsma) was measured using an ultrasonic flow probe. Ileal intramucosal hydrogen ion concentration, [H+]1, was estimated tonometrically. Pigs in groups I and II were infused with endotoxin (250 micrograms/kg) and resuscitated with saline (1.2 ml/kg min). Group I (n = 8) were controls; Group II (n = 8) were pretreated with LY203647 (30 mg/kg bolus, then 10 mg/kg h). Treatment with LY203647 persistently and significantly (P less than .05) improved post-LPS pO2 and transiently improved Qsma. Treatment with LY203647 did not affect [H+]1. Lung extravascular wet-to-dry weight ratios were 7.13 +/- .33 and 5.43 +/- .09 in groups I and II, respectively (P less than .001). These data suggest that sulfidopeptide LT are important mediators of key pathophysiologic events in this porcine model of endotoxic shock and the adult respiratory distress syndrome (ARDS).

LY171883 preserves mesenteric perfusion in porcine endotoxic shock

Superior mesenteric arterial perfusion (Q) decreases and gut intramucosal hydrogen ion concentration, [H+], increases in resuscitated normodynamic endotoxic pigs. The present study tested the hypothesis that these adverse phenomena can be prevented by pretreatment with LY171883, a specific leukotriene (LT) D4/E4 receptor antagonist. Pentobarbital-anesthetized pigs (14-18 kg) were instrumented to permit measurement of Q (ultrasonic flow probe) and [H+] (tonometer). Mesenteric O2 delivery (DO2) and consumption (VO2) were calculated from the O2 contents of arterial and superior mesenteric venous blood. At t = -20 min, groups (N = 6) of pigs were pretreated witH LY171883 (10 mg/kg) or vehicle. At t = 0 min, the pigs were infused over 20 min with lipopolysaccharide (LPS; 150 micrograms/kg) and resuscitated for 2 hr with saline (1.2 ml/kg min). Irrespective of treatment group, mean arterial pressure and systemic vascular resistance index decreased significantly after infusion of LPS. In general, cardiac index (CI) was well preserved, although in controls at t = 20, 100, and 120 min, CI decreased significantly with respect to the t = 0 min value. Normal mesenteric Q and DO2 were maintained in the LY171883 group, whereas, in controls, these parameters decreased significantly. Mesenteric VO2 increased transiently but significantly in controls; this phenomenon was abrograted by the LT receptor antagonist. In controls, intramucosal [H+] increased by almost threefold; this adverse effect was significantly ameliorated by LY171883. These data suggest that decreased mesenteric Q and increased intramucosal [H+] may be mediated by LT in this porcine endotoxic shock model.

Are low tidal volumes safe?

High airway pressure may be injurious to lung parenchyma, but lowering airway pressure using conventional mechanical ventilation necessitates lowering tidal volume (VT). Intubated patients in the surgical intensive care unit (SICU) were randomly assigned to group 1 (VT = 12 ml/kg, n = 56) or group 2 (VT = 6 ml/kg, n = 47). Variables recorded included acute physiology and chronic health evaluation (APACHE II) score, mean peak airway pressure (MPAP), mean PaO2/FIO2, incidence of pulmonary infectious complications (PIC), duration of intubation (DOI), and duration of SICU stay (DOS). Results in the table are means +/- SE. (table; see text) The incidence of pulmonary infection tended to be lower and DOI and DOS tended to be shorter for nonneurosurgical and noncardiac surgical patients randomized to low VT, suggesting that morbidity may be decreased. The use of low VT was associated with a statistically significant but clinically irrelevant decrease in oxygenation. The routine use of low VT appeared to be safe in a selected population of patients in the SICU.

The efficacy of an oscillating bed in the prevention of lower respiratory tract infection in critically ill victims of blunt trauma. A prospective study

We tested the hypothesis that the incidence of LRTI in critically ill blunt trauma victims can be reduced by employing continuous postural oscillation. Within 24 h of admission to the SICU, 106 patients were prospectively randomized to either a conventional bed or a RRKTT. Seven patients who were discharged from the SICU in less than 24 h were excluded from the data analyses. Until discharge from the SICU, patients were monitored daily for development of LRTI or pneumonia. Among 48 patients in the control group, 28 met criteria for LRTI and 19 met criteria for pneumonia. Among 51 patients in the RRKTT group, 13 developed LRTI and 7 developed pneumonia. The differences between groups for all LRTI and pneumonia were both significant. We conclude that continuous postural oscillation decreases the risk of pulmonary sepsis in victims of major blunt trauma.

Fulminant hepatic failure caused by acute fatty liver of pregnancy treated by orthotopic liver transplantation

A previously healthy 35-year-old woman was seen at 37 weeks' gestation with a 10-day history of fever, vomiting, diarrhea and malaise. Serum laboratory findings included elevation of serum bilirubin and AST, prolongation of serum prothrombin time and a positive monospot. A tentative diagnosis of acute fatty liver of pregnancy was made, and a healthy male infant was delivered by emergency cesarean section because of fetal distress. Over the subsequent 3 days, acute progressive oliguric renal failure, disseminated intravascular coagulation, hypoglycemia requiring intravenous dextrose infusion and pancreatitis developed; her mental status progressed to stage III encephalopathy. Quantitative computed tomography estimated the liver volume to be 770 cm3. The decision to proceed with orthotopic liver transplantation was made on the basis of progressive clinical deterioration despite aggressive support and because of her small liver size. After transplant, the patient's multisystem failure rapidly reversed. Histopathological examination of the native liver demonstrated predominantly zone 3 microvesicular steatosis with characteristic ultrastructural changes consistent with acute fatty liver of pregnancy. Southern blot analysis for Epstein-Barr virus DNA was negative. We conclude that orthotopic liver transplantation should be considered for the small group of patients with fulminant hepatic failure associated with acute fatty liver of pregnancy who manifest signs of irreversible liver failure despite delivery of the fetus and aggresive supportive care.

Systemic and mesenteric O2 metabolism in endotoxic pigs: effect of ibuprofen and meclofenamate

The effect of two chemically dissimilar cyclooxygenase inhibitors was studied in pentobarbital-anesthetized endotoxic pigs. Animals in groups II-IV were infused with Escherichia coli lipopolysaccharide (LPS, 150 micrograms/kg) and resuscitated with normal saline (1.2 ml.kg-1.min-1). Animals in group I (n = 4) were resuscitated as above but were not infused with LPS. Animals in group II (n = 7) served as endotoxic controls. Pigs in groups III (n = 6) and IV (n = 5) were pre- and posttreated with ibuprofen (10 mg/kg bolus then 10 mg.kg-1.h-1 and meclofenamate (5 mg/kg then 5 mg.kg-1.h-1, respectively. Ileal intramucosal hydrogen ion concentration [( H+]) was estimated tonometrically. In group I, cardiac index (CI), mean arterial pressure (MAP), superior mesenteric arterial perfusion (QSMA), and mesenteric O2 delivery (DO2) increased significantly, but other variables were unchanged. After infusion of LPS in group II, MAP and systemic vascular resistance index were markedly diminished but CI was well preserved. In this group, QSMA, systemic DO2, and mesenteric DO2 decreased, whereas systemic O2 uptake (VO2) and gut [H+] increased; mesenteric VO2 was unchanged. Compared with pigs in group II, pigs treated with ibuprofen or meclofenamate manifested improved systemic and mesenteric DO2. In groups III and IV, QSMA remained normal, increased systemic VO2 was not observed, and gut intramucosal acidosis was ameliorated. Increased intramucosal [H+] in group II suggests that QSMA was inadequate. The salutary effects of ibuprofen and meclofenamate suggest that inadequate mesenteric perfusion was mediated, at least in part, by cyclooxygenase-derived metabolites or arachidonic acid.

Complement depletion with Naje haje cobra venom factor limits prostaglandin release and improves visceral perfusion in porcine endotoxic shock

We tested the hypothesis that complement (C')-dependent release of prostaglandin (PG) I2 is an important factor contributing to the development of hypotension and low systemic vascular resistance index (SVRI) in endotoxic shock. Two groups (n = 7) of pentobarbital-anesthetized pigs (12-15 kg) were infused over 40 min with Escherichia coli lipopolysaccharide (LPS; 200 micrograms/kg) and continuously resuscitated with normal saline (1 ml/kg min): LPS-Control (no pretreatment) and LPS-Decomplemented (pretreatment 18 hr before study with 500-1,500 units of Naje haje cobra venom factor, CVF). Prior treatment with CVF: i) decreased the mean titer of total hemolytic C' to 15.9% of pretreatment levels; ii) significantly decreased post-LPS plasma concentrations of immunoreactive TxB2 (TxA2 metabolite) and 6-keto-PGF1 alpha (PGI2 metabolite); iii) abrogated the early transient decrease in cardiac index observed in the LPS-Control group; iv) tended to improve post-LPS visceral perfusion assessed using radioactive microspheres; and v) had no discernible effect on the late sustained decrease in SVRI observed following infusion of LPS. We conclude that C' activation is a major determinant of LPS-induced prostanoid release in vivo, although our results do not support the view that C'-dependent release of PGI2 is an important factor contributing to low SVRI in resuscitated endotoxic shock.

Effect of lipopolysaccharide on intestinal intramucosal hydrogen ion concentration in pigs: evidence of gut ischemia in a normodynamic model of septic shock

We tested the hypothesis that lipopolysaccharide (LPS) leads to an imbalance between mesenteric oxygen delivery (DO2) and gut metabolic demand for oxygen, even when cardiac index (CI) is within the normal range. Two groups of pentobarbital-anesthetized pigs (13 to 17 kg) were studied. The first group (LPS; n = 9) was infused over 20 min with Escherichia coli LPS (100 micrograms/kg) and resuscitated with normal saline (1.2 ml/kg.min). The second group (NS; n = 5) was not infused with LPS, but was resuscitated in the same way as the LPS group. Superior mesenteric arterial (SMA) blood flow and ileal intramucosal hydrogen ion concentration, [H+], were determined using a Doppler-shift probe and a tonometric catheter, respectively. Infusing LPS did not affect CI, although mean arterial pressure and systemic vascular resistance were significantly reduced. SMA flow and mesenteric DO2 decreased significantly in the LPS group. Although mesenteric oxygen utilization was well preserved in both groups, ileal intramucosal [H+] was significantly higher in endotoxic animals. These data support the idea that mesenteric oxygen consumption is flow-limited in this clinically relevant porcine model of septic shock.

Pyogenic sacroiliitis: another imitator of the acute abdomen

Acute suppurative infection of the sacroiliac joint can mimic the acute abdomen. Experience with a patient who had exploratory laparotomy for acute appendicitis prompted a review of the literature, which indicated that 12.6% of patients with pyogenic sacroiliitis have acute abdominal pain. A high index of suspicion is necessary to establish this diagnosis.

The distribution of DNA excision-repair sites in human diploid fibroblasts following ultraviolet irradiation

Using the technique for separating DNA fragments containing excision-repair sites from total genomic DNA as described in the previous paper (Cohn, S. M., and Lieberman, M. W. (1984) J. Biol. Chem. 259, 12456-12462), we have developed a method for directly determining the distribution of excision-repair sites in the genome. DNA was prepared from confluent, diploid human fibroblasts which had been irradiated with ultraviolet light and incubated in the presence of 5-bromo-2'-deoxyuridine (BrdUrd), repaired fragments were isolated, and the dependence of the fraction of total DNA fragments containing excision-repair sites on DNA fragment length was determined by electrophoretic analysis. The observed dependence was compared to the relationship expected for a random distribution of repair sites. At 36 h following 3 J/m2 UV, the distribution of repair sites was indistinguishable from a random distribution; however, at doses of UV above 6 J/m2, the observed dependence indicated that the distribution of repair sites was nonrandom. A time course of the distribution of repair sites following 12 J/m2 UV was clearly nonrandom from 4 h after irradiation until at least 36 h following irradiation. By 72 h, however, the distribution had become random. In cells treated with hydroxyurea, a reduced number of excision-repair sites were present, but the distribution of repair sites was also nonrandom. Autoradiographic analysis of the amount of unscheduled DNA synthesis in individual nuclei suggested that the nonrandom distribution of repair sites did not result from variable extents of repair synthesis in different cell populations or from cell death.

The use of antibodies to 5-bromo-2'-deoxyuridine for the isolation of DNA sequences containing excision-repair sites

We have developed an immunological method for isolation and identification of DNA sequences containing 5-bromo-2'-deoxyuridine (BrdUrd) incorporated during UV-induced excision-repair synthesis. DNA fragments containing BrdUrd incorporated during repair synthesis were incubated with goat anti-BrdUrd and rabbit anti-goat IgG, and the antibody-DNA complexes were separated from bulk DNA by nitrocellulose filter binding. With this method, 80% of DNA sequences containing BrdUrd-labeled excision-repair sites were recovered, contaminated with less than 1% of DNA fragments devoid of excision-repair sites. Recovery of DNA fragments containing repair sites was independent of size from 2 to 20 kilobases. We have used this method in conjunction with blot hybridization to demonstrate that repair synthesis occurs in human ribosomal gene sequences in cells treated with UV.