Variables influencing patients' outcomes after elective aortic reconstruction surgery

BACKGROUND: Aortic reconstruction surgery for aneurysmal and occlusive disease is associated with significant morbidity and mortality. OBJECTIVES: To determine what variables influence patients' outcomes after elective aortic reconstruction surgery so that an evidence-based best-practice initiative can be developed for these patients. METHODS: A descriptive, comparative study of all patients undergoing elective aortic reconstruction from October 1997 through December 1998 was used. Retrospective chart review was used to collect demographic and clinical data on the first 48 subjects, who had been discharged from the hospital. Data on the other 63 subjects were collected prospectively. RESULTS: The typical subject was a 65-year-old man with a history of cardiovascular disease, hypertension, and smoking. Subjects were grouped by type of surgery and by outcome (survived without complications vs died or survived with major complications). Outcomes were not significantly different in patients undergoing different types of surgery. Variables associated with poor outcomes included history of cardiovascular disease, elevated preoperative levels of serum urea nitrogen and creatinine, high volumes of salvaged autologous blood administered intraoperatively, and early postoperative hypotension that required treatment. Pulmonary complications were the most common; next most common were cardiac complications. History of cardiovascular disease and hypotension were significant predictors of outcome. CONCLUSION: The variables associated with poor outcomes can be used to design a best-practice initiative for patients undergoing elective aortic reconstruction.

Acute vs. chronic effects of elevated hemoglobin O(2) affinity on O(2) transport in maximal exercise

These studies were conducted to compare the effects on systemic O(2) transport of chronically vs. acutely increased Hb O(2) affinity. O(2) transport during maximal normoxic and hypoxic [inspired PO(2) (PI(O(2))) = 70 and 55 Torr, respectively] exercise was studied in rats with Hb O(2) affinity that was increased chronically by sodium cyanate (group 1) or acutely by transfusion with blood obtained from cyanate-treated rats (group 2). Group 3 consisted of normal rats. Hb O(2) half-saturation pressure (P(50); Torr) during maximal exercise was approximately 26 in groups 1 and 2 and approximately 46 in group 3. In normoxia, maximal blood O(2) convection (TO(2 max) = cardiac output x arterial blood O(2) content) was similar in all groups, whereas in hypoxia TO(2 max) was significantly higher in groups 1 and 2 than in group 3. Tissue O(2) extraction (arteriovenous O(2) content/arterial O(2) content) was lowest in group 1, intermediate in group 2, and highest in group 3 (P < 0.05) at all exercise PI(O(2)) values. In normoxia, maximal O(2) utilization (VO(2 max)) paralleled O(2) extraction ratio and was lowest in group 1, intermediate in group 2, and highest in group 3 (P < 0.05). In hypoxia, the lower O(2) extraction ratio values of groups 1 and 2 were offset by their higher TO(2 max); accordingly, their differences in VO(2 max) from group 3 were attenuated or reversed. Tissue O(2) transfer capacity (VO(2 max)/mixed venous PO(2)) was lowest in group 1 and comparable in groups 2 and 3. We conclude that lowering Hb P(50) has opposing effects on TO(2 max) and O(2) extraction ratio, with the relative magnitude of these changes, which varies with PI(O(2)), determining VO(2 max). Although the lower O(2) extraction ratio of groups 2 vs. 3 suggests a decrease in tissue PO(2) diffusion gradient secondary to the low P(50), the lower O(2) extraction ratio of groups 1 vs. 2 suggests additional negative effects of sodium cyanate and/or chronically low Hb P(50) on tissue O(2) transfer.

Variables influencing patients' outcomes after elective aortic reconstruction surgery

BACKGROUND

Aortic reconstruction surgery for aneurysmal and occlusive disease is associated with significant morbidity and mortality.

OBJECTIVES

To determine what variables influence patients' outcomes after elective aortic reconstruction surgery so that an evidence-based best-practice initiative can be developed for these patients.

METHODS

A descriptive, comparative study of all patients undergoing elective aortic reconstruction from October 1997 through December 1998 was used. Retrospective chart review was used to collect demographic and clinical data on the first 48 subjects, who had been discharged from the hospital. Data on the other 63 subjects were collected prospectively.

RESULTS

The typical subject was a 65-year-old man with a history of cardiovascular disease, hypertension, and smoking. Subjects were grouped by type of surgery and by outcome (survived without complications vs died or survived with major complications). Outcomes were not significantly different in patients undergoing different types of surgery. Variables associated with poor outcomes included history of cardiovascular disease, elevated preoperative levels of serum urea nitrogen and creatinine, high volumes of salvaged autologous blood administered intraoperatively, and early postoperative hypotension that required treatment. Pulmonary complications were the most common; next most common were cardiac complications. History of cardiovascular disease and hypotension were significant predictors of outcome.

CONCLUSION

The variables associated with poor outcomes can be used to design a best-practice initiative for patients undergoing elective aortic reconstruction.

Studies on the IgA-independent immunological responses in mice to influenza virus challenge after oral vaccination with irradiated whole virus and an erythrocyte complex

Previous studies have described an oral influenza vaccine comprising whole irradiated virus and an erythrocyte complex (IV-EC), which gave broad-based protection against influenza virus challenge in mice. The present study examined the immune responses generated after live virus challenge of vaccinated mice, particularly to determine whether mice vaccinated with IV-EC had enhanced CTL activity to compensate for the previously reported diminution in lung IgA response. Oral vaccine groups examined were IV-EC, live virus alone (LV) or live virus-erythrocyte complex (LV-EC), compared with irradiated virus and erythrocyte alone controls. The antibody responses of IV-EC and LV-EC vaccinated mice showed significantly elevated lung and serum IgG2a levels post live virus challenge, with no comparable increases in IgG1 levels compared to controls. Spleen cells from IV-EC mice showed an enhanced post-challenge proliferative response to antigen compared with mice that had received live oral vaccines, indicating enhanced cellular activity post IV-EC immunization. However, CTL activity was not enhanced for IV-EC mice, and live virus-vaccinated mice had reduced CTL activity compared with controls, indicating that CTL were not important for post-vaccine protection. Cytokine analysis revealed a predominant IFN-gamma response in spleen cells from orally vaccinated mice, whereas IL-4 was not detected in any lung or spleen culture analysed. The results suggest, therefore, that protection from live influenza challenge after IV-EC or LV-EC vaccination was due to an IFN-mediated IgG2a response. Definitive confirmation of the role of these factors in post-vaccine protection can now be tested in IgG2a-depleted or IFN-gamma gene knockout mouse models.

Influenza virus inhibits lysozyme secretion by sputum neutrophils in subjects with chronic bronchial sepsis

Neutrophils are central to the control of infection within the bronchial mucosa. To determine whether the link between bacterial and viral infection in the respiratory tract can be partly explained by acute reduction of neutrophil function, we examined the influence of influenza virus on lysozyme secretion by sputum neutrophils obtained from patients with bronchiectasis. Sputum neutrophils infected with influenza A virus had a significantly reduced capacity to secrete lysozyme but not myeloperoxidase. Influenza virus A strains were more effective in inhibiting lysozyme secretion than were influenza B virus strains. Reduction of bactericidal activity was similarly reduced by different strains of influenza A virus, but an influenza virus B strain had no effect. Our results show that downregulation of sputum neutrophil function characterized by lysozyme secretion and bactericidal activity could contribute to reduction in the capacity to control bacterial colonization in the respiratory tract following influenza virus infection.

Ethanol-altered liver-associated T cells mediate liver injury in rats administered Concanavalin A (Con A) or lipopolysaccharide (LPS)

BACKGROUND

Recent work from our laboratory implicates T cells in the pathogenesis of alcoholic liver disease. We have studied the role of liver-associated T cells in acute hepatitis produced in control rats administered Concanavalin A (Con A) after adoptive transfer of T cells from alcohol-consuming animals.

METHODS

Liver-associated T cells from ethanol-consuming rats were transferred via tail vein to nonethanol-consuming rats. They then received Con A (20 mg/kg body weight) intravenously. This produced a severe hepatitis. Serum was collected for the assay of alanine aminotransferase (ALT) and cytokines.

RESULTS

Hepatic necrosis was accompanied by an increase in plasma levels of ALT, interleukin-6, and tumor necrosis factor-alpha. These increases correlated with increased production of interleukin-6 and tumor necrosis factor-alpha in culture of liver-associated T cells stimulated or unstimulated with Con A. Immunohistology staining showed increased infiltration of inflammatory cells comprised of neutrophils and mononuclear cells, which included greater numbers of CD4+ T cells in the portal tract areas and around the central vein. Focal and lobular necrosis was seen with inflammatory cells in the necrotic area. Hepatocytes isolated from the liver showed increased apoptosis compared with rats that received liver-associated T cells from nonethanol-consuming rats. Injection of endotoxin LPS, in the same model, was associated with less hepatocyte injury indicating a distinct role for T cells as opposed to Kupffer cells in this model of liver disease.

CONCLUSIONS

Chronic ethanol consumption induces a lesion in a pool of liver-associated T cells which can mediate liver injury after polyclonal mitogen activation.

Coccoid forms of Helicobacter pylori can be viable

Controversy exists as to whether the coccoid form of Helicobacter pylori can exist in a viable form. Conversion of helical to coccoid morphology occurs in culture over several days. In this study, the morphology was correlated with parameters of genetic integrity in the reference NCTC 11637 strain over 21 days of culture. The capacity to regrow colonies of helical form was demonstrated from a culture where the coccoid form constituted up to 95% and negligible urease activity could be detected. Urease enzyme activity and its mRNA decreased between day 0 and 10 while 26 kD mRNA and 16S rRNA were expressed unchanged for up to 14 and 21 days of culture, respectively. Expression of mRNA for the Cag A gene behaved in a similar fashion to that of urease. No evidence of DNA fragmentation was detected. These data suggest that a viable form of non-urease producing H. pylori exists after short to intermediate culture and that some if not all of these viable bacteria have coccoid morphology.

Nitric oxide alters chondrocyte function by disrupting cytoskeletal signaling complexes

Components of osteoarthritis include increases in pericellular fibronectin and in chondrocyte beta1 integrin expression. Events which follow ligation of fibronectin to its chondrocyte-receptor, the integrin alpha5beta1 include an assembly of a subplasmalemmal actin/rho A/focal adhesion kinase signaling complex. In addition, nitric oxide (NO), a potential mediator of cartilage pathophysiology disrupts the cytoskeletal signaling complex associated with integrin signaling. In these studies, we examined the relationship among integrin signaling, biosynthesis of S-35 sulfate containing proteoglycans and release of YKL-40 (a secretory glycoprotein) by comparing cell responses using cells plated on a fibronectin-coated or polyHEME coated surfaces. We report that the release of proteoglycan and glycoprotein require anchorage dependent signals by integrin costimulation. NO which disrupts the integrin signaling complex attenuates both cell responses. Taken together NO may serve as a nonspecific 'brake' to prevent anabolic and catabolic injury responses.

Effect of demineralized bone matrix on polymorphonuclear leukocyte degranulation

The potential use of allogenic demineralized bone matrix to augment or treat bone defects or nonunions in animals and humans is currently being investigated. Demineralized bone matrix induces osteogenesis by a multistep cascade of endochondral ossification that is mediated by bone-induction factors. The migration and activation of polymorphonuclear leukocytes appear to be critical in the initiation of the cascade of osteogenesis induced by demineralized bone matrix. This study examined the effects of demineralized bone matrix on the degranulation of polymorphonuclear leukocytes. Demineralized bone matrix stimulated the release of polymorphonuclear leukocyte-specific, but not azurophilic, granules in a time and dose-dependent manner. The ability of the bone matrix to induce this degranulation was independent of its size and species. The mechanism by which this degranulation occurs is not completely understood; however, it is known that it does not occur by means of a receptor that requires guanidine triphosphate-dependent regulatory proteins as does polymorphonuclear-leukocyte degranulation induced by N-formyl peptide. The factor that stimulates degranulation is not type-I collagen but rather appears to be a cytokine that has a heparin-binding domain and a molar mass of 10-70 kDa. Loss of the ability of demineralized bone matrix to induce degranulation of polymorphonuclear leukocytes correlated positively with the loss of its ability to induce bone formation.

The effect of cigarette smoking status on six-minute walk distance in patients with intermittent claudication

The purposes of the study were threefold: (1) to compare 6-minute walk performance as a measure of exercise tolerance among three different groups of peripheral arterial occlusive disease (PAOD) patients with intermittent claudication-current smokers, former smokers, and patients who have never smoked; (2) to identify important covariates that might affect the relationship between smoking and exercise in the PAOD population; (3) to determine whether differences among the three groups in 6-minute walk performance persist after statistically controlling for the significant covariates. Recruited into the study were 415 PAOD patients with intermittent claudication between the ages of 42 and 88 years. The self-reported smoking status consisted of 182 current smokers, 196 former smokers, and 37 patients who had never smoked. The authors recorded 6-minute walk distance, a reliable measurement of exercise tolerance in PAOD patients, as well as age, body composition, self-reported ambulatory function, self-reported physical activity, and standard peripheral hemodynamics. Nonsmokers walked significantly farther (413 +/- 14 m; mean +/- standard error) and took more steps (665 +/- 14 steps) than either current (352 +/- 7 m; 563 +/- 9 steps) or former smokers 370 +/- 7 m; 600 +/- 8 steps) (p<0.05). The nonsmokers had a higher ankle-brachial index (ABI) value (0.70 +/- 0.03) than patients who actively smoked 0.62 +/- 0.01 (p<0.03); the authors observed an inverse relationship between smoking history and self-reported physical activity (WIQ Distance Score: nonsmokers 51 +/- 6%, former smokers 38 +/- 3%, and smokers 32 +/- 2%) (p<0.01). From a multivariate perspective, ABI, physical activity, and perceived walking ability were the only independent predictors of 6-minute walk distance. Differences in the adjusted 6-minute walk distance among the nonsmokers (388 +/- 13 m), current smokers (359 +/- 6 m), and former smokers (368 +/-6 m) no longer remained after controlling statistically for these covariates. The findings suggest that 6-minute walk distance is a sensitive measure to detect differences in submaximal exercise performance between smoking and nonsmoking PAOD patients with intermittent claudication. Moreover, the group difference in the 6-minute walk distance is explained by group differences in walking perception, PAOD severity, and physical activity level.

IL-6, IFN-gamma and TNF-alpha production by liver-associated T cells and acute liver injury in rats administered concanavalin A

The relationship between the development of acute hepatitis and the production of TNF-alpha IFN-gamma and IL-6 by liver-associated T lymphocytes following intravenous injection of concanavalin A (Con A) was studied in rats. Following a single injection of Con A, there was a dose and time-dependent correlation in the serum levels of serum alanine aminotransferase (ALT), IL-6, IFN-gamma and TNF-alpha. These increases correlated with an increase in the numbers of CD4+, CD8+ and CD25+ T cells in blood and CD4+ and CD25+ T cells in the liver perfusate, but not with CD8+ T cells in liver perfusate. Increased levels of IL-6, IFN-gamma and TNF-alpha were constitutively produced by liver-associated CD4+ T cells when cultured. In Con A-stimulated cultures, liver-associated CD4+ T cells secreted increasing levels of TNF-alpha in a time-dependent manner following Con A injection, but TNF-alpha production by peripheral blood lymphocytes was transient with peak levels detected at 1 h which then declined over 24 h. Histological examination of the liver revealed fatty change, hepatocyte degeneration and necrosis, with an associated cell infiltrate of neutrophils and CD4+ T cells both in the portal areas and around the central veins. These results support the hypothesis that Con A-induced liver damage is mediated by CD4+ T cells acting within the liver, at least in part through the secretion of TNF-alpha, IFN-gamma and IL-6.

Möbius syndrome with oculomotor nerve paralysis without abducens paralysis

Möbius syndrome is typified by bilateral facial nerve palsies, usually with abducens palsies. We examined an infant with Möbius syndrome who had bifacial weakness and third nerve palsies, but intact abduction of both eyes. Lower cranial nerve involvement, leading to respiratory, swallowing, and cardiac difficulties, was also present. Pathologic examination of the brainstem showed absent or hypoplastic third, seventh, tenth, and twelfth nerve nuclei. The fourth, fifth, sixth, and eighth nerve nuclei were intact. In Möbius syndrome with ocular motor palsies, rarely the sixth nerve may be spared.

Altered T-lymphocyte responsiveness to polyclonal cell activators is responsible for liver cell necrosis in alcohol-fed rats

The role of T-cell activation in alcoholic liver disease was investigated in rats fed alcohol and subsequently exposed to concanavalin A (Con A). Following Con A injection (20 mg/kg body weight), greater increases in liver-to-body weight ratio and ALT levels were observed at 12 and 24 hr in rats fed ethanol, compared with control rats fed sucrose. Furthermore, increases in serum interleukin-6 and tumor necrosis factor-alpha levels were noted in ethanol-fed rats, with maximal levels detected at 4 hr declining thereafter, but remaining above control levels at 24 hr. Analysis of T-cell subpopulations showed an increased percentage of CD4+, CD5+, and CD8+ T cells in blood from all groups, but not in liver perfusate. In contrast, a significant increase in the percentage of activated CD25+ T cells was detected in both blood and liver perfusate from rats fed ethanol even 24 hr after Con A injection. When CD4+ and CD8+ T cells from liver perfusate were cultured in the absence or presence of Con A, an increase in interleukin-6 and tumor necrosis factor-alpha production in supernatants was observed in ethanol-fed rats. In cultures stimulated with Con A, a 2- to 8-fold increase in cytokine production was detected, with intrahepatic CD4+ T cells being the major source. Immunohistological analysis revealed infiltration of CD4+ T cells around portal vein and central vein areas associated with fatty liver and severe hepatic necrosis. The results suggest that alcohol consumption induced a dysregulated T-cell population that mediated hepatic necrosis following polyclonal activation with Con A.

Microbial-linked diseases--shifting the pathogenic paradigm. 25-26 June 1998, San Diego, USA

This innovative cross-discipline conference brought together an international cohort with widely different backgrounds to address 'hard' infections in a way that is unusual in the modern era. The success of this 'experiment' was reflected by the strong and enthusiastic support from all the attendees present, with the hope that this meeting will be the first of many. The meeting was introduced by a review of the parallel development of a scientific framework within which the clinical pressures of the day must be considered if therapeutic progress is to occur. The simple paradigm of infection driving an antibody response identified as protection, proved of value at the turn of the century when epidemic infectious diseases prevailed. Such a paradigm is hopelessly inadequate to cope with the new pressures of degenerative disease, neoplasia, and chronic inflammatory disease, which now dominate the clinical agenda and with which 'infection' is tenuously linked. The excitement of the discovery that many of our major health challenges are outcomes of interaction between microbes and the host response, was the theme of this meeting. Subtle variations in microbial pressure or host response, have focused attention on genetic background, compartmentalized response and microbe distribution, persistence of antigen, 'escape' forms of the microbe, inappropriate host responses which damage through hypersensitivity mechanisms, and perpetuation of disease through the triggering of autocrine or autoimmune mechanisms. Two particularly important factors are the role of dysfunctional T-lymphocytes and variable outcomes influenced by the 'dose-response' curve, which can determine up- or downregulation of the immune response. The various presentations given provided excellent models of these general principles, and will be discussed in this context.

Decreased tumor necrosis factor-alpha and interleukin-1alpha production from intrahepatic mononuclear cells in chronic ethanol consumption and upregulation by endotoxin

The relationship between the changes in liver pathology and the production of interleukin (IL)-1alpha, IL-6, and tumor necrosis factor-alpha (TNF-alpha) by intrahepatic mononuclear cells was studied in rats fed alcohol and subsequently exposed to lipopolysaccharide (LPS). Rats were fed 40% ethanol in drinking water, whereas control rats were provided with a chow diet with isocaloric or 2% sucrose drinking solutions for up to 20 weeks. Decreased IL-1alpha and TNF-alpha production in 24-hr culture supernatants of mononuclear cells isolated from liver perfusate was detected while IL-6 remained unchanged over 20 weeks. When animals were injected with LPS (1.0 microg/kg body weight), there was a 5-fold rise in ALT levels in the ethanol-fed group, but not in control groups. Increased IL-6 and TNF-alpha levels in the serum and supernatant of cultured intrahepatic mononuclear cells stimulated with or without LPS or concanavalin A was observed. There was a correlation between levels of ALT and TNF-alpha, but not IL-6. T cells and Kupffer cells were the major source of TNF-alpha in culture supernatants of hepatic perfusate mononuclear cells from ethanol-consuming rats injected LPS. In addition, pathological liver injury was evident, which suggests a pathogenic role for TNF-alpha in alcohol-induced liver disease.

Erythrocytes enhance the immunogenicity of oral vaccination with gamma irradiated influenza virus: increasing the dose of irradiation results in a significant diminution of lung IgA response

Previous studies have demonstrated that the ability of gamma-irradiated whole influenza virus to prime for specific anti-influenza antibody responses was dramatically enhanced when delivered in a complex with chicken red blood cell ghosts (cRBC). The purpose of this study was to investigate the effect of increasing the dose of gamma irradiation used to inactivate A/Queensland/6/72 virus on the ability of the virus-cRBC complex to prime for specific influenza responses. Spleen cell proliferation studies confirmed the enhancing effect of the cRBC carrier for oral vaccination with irradiated virus. Cells from mice vaccinated with 30 kGy-irradiated virus only did not respond to influenza stimulation in vitro, whereas cells from mice vaccinated with irradiated virus+cRBC showed significant increases in proliferation to antigen exposure. No significant antibody response or challenge virus clearance was observed in mice orally vaccinated with irradiated (13.1 or 30 kGy) virus alone, even when the dose was increased significantly. Oral vaccination with live virus (+/-cRBC) primed for significant influenza specific IgA responses in the lungs, in addition to IgG responses in the lungs and sera. The dose of irradiation used to inactivate the virus was found to be critical to the profile of antibody response when the virus was delivered in a complex with cRBC. Oral vaccination of Swiss mice with 13.1 or 30 kGy virus (+cRBC) primed for significant serum and lung IgG responses. Lung IgA responses for 13.1 kGy+cRBC vaccinated mice were detected, but 30 kGy+cRBC vaccinated Swiss and CBA/H mice had no significant lung IgA response. The abrogation of IgA response, however, did not lessen the clearance of live challenge virus in outbred mice, suggesting a primary role for IgG and/or CTL response in the control of influenza virus infection post oral vaccination. To ensure direct comparison of virus alone and virus+cRBC treatments, the concentration of virus complexed to the cRBC was determined.

Autocrine modulation of IL-8 production by sputum neutrophils in chronic bronchial sepsis

We examined the activity of neutrophils isolated from sputum and blood of subjects with chronic bronchial sepsis in terms of interleukin-8 (IL-8), IL-1beta, and tumor necrosis factor-alpha (TNF alpha) production. In sputum, the numbers of neutrophils correlated with the concentrations of these cytokines. Sputum neutrophils constitutively secreted large amounts of IL-8, IL-1beta, and TNF alpha. The patterns of secretion, however, differed from those of blood neutrophils stimulated with bacterial lipopolysaccharide (LPS). Cytokine secretion was time-dependent and was inhibited by cycloheximide and dexamethasone. IL-10 inhibition of IL-8 production by sputum neutrophils was significantly less than that noted with activated neutrophils. Antibody to IL-1beta but not to TNF alpha, inhibited IL-8 secretion by sputum neutrophils, contrasting with results found using blood neutrophils. Incubation of blood neutrophils in sputum sol induced a similar cytokine secretion profile to that following exposure to LPS. The inhibitory effects on IL-8 protein production correlated with messenger RNA (mRNA) gene expression. These observations indicate that neutrophils are a significant source of IL-8 in purulent sputum, and that an autocrine loop involving IL-1beta maintains secretion within the bronchus lumen.

Immunologic, functional, and morphological characterization of three new human small intestinal epithelial cell lines

BACKGROUND & AIMS

Epithelial cell cultures can be used for the study of epithelial cell biology, although human small intestinal cultures have not been available to date. The aim of this study was to characterize three cell lines derived from normal human duodenum.

METHODS

Cells were cultured from tissue fragments obtained from endoscopic biopsy specimens and characterized with respect to morphology and cytokine gene expression and for the presence of vectorial transport.

RESULTS

All cell lines grew as polarized continuous monolayers and were mostly cuboidal in shape but were not immortalized. Cells showed junctional complexes and sparse microvilli. All cell lines showed cytokeratins and mucin antigen but not chromagranin and messenger RNA for epidermal growth factor, interleukin 6, and vascular cell adhesion molecule 1. Disaccharidase activities were low and correlated with the low proportion of cells (1%-10%), showing positive immunocytochemistry for sucrase. Monolayer resistance varied from 30 to 200 ohms. One monolayer (BN) consistently showed secretion in response to forskolin (10 micromol/L), which could b inhibited by chloride-free buffer and apical addition of the chloride channel blocker diphenylamine decarboxylate. No monolayer had evidence of glucose transport.

CONCLUSIONS

These three nonimmortalized lines show morphological, phenotypic, and transport characteristics of crypt-like intestinal epithelial cells. The pattern of messenger RNA expression suggests a growth-promoting and immunomodulatory role.

Pseudoseizures in the pediatric emergency department

We report 10 cases of children with pseudoseizures who presented to a pediatric emergency department. Half of the patients were teenagers and seven were female. None of the patients had incontinence, and none was injured during the "seizure." All but one patient had invasive procedures or laboratory tests performed in the emergency department, and six of 10 patients were given anticonvulsants. Pseudoseizures are often confused with generalized tonic-clonic seizures.

Acute on chronic bronchitis: A model of mucosal immunology

Acute bronchitis has been studied as a model of disturbed mucosal immunoregulation. A new hypothesis relating to the pathogenesis of acute bronchitis has been developed, based on altered host response as the prime mover. Infection-prone subjects had low levels of lysozyme. Effective oral immunization, especially if early, reduced levels of bacterial colonization. Future attention focuses on intra bronchial inflammation and its link to the host-parasite relationship.

Exclusion mapping of chromosomal regions which cross hybridise to FSHD1A associated markers in FSHD1B

Facioscapulohumeral muscular dystrophy (FHSD) is a genetically heterogeneous, autosomal dominant primary disease of muscle. The predominant form of FSHD, which has been designated FSHD1A, has been localised to the 4q34 region of human chromosome 4. The disease locus (loci) for the remaining FSHD families, which are not linked to chromosome 4 and have been designated FSHD1B, has not yet been identified.

The D4F104S1 marker which detects copies of a 3·2 kb tandem repeat (D4Z4) which contains several types of repetitive sequences, including Hox gene-like elements, has been shown to be closely linked to the chromosome 4 FHSD disease locus. The loss of an integral number of the 3·2 kb tandem repeats has been associated with FSHD1A. When hybridised to chromosomal spreads these sequences cross hybridise with heterochromatin on acrocentric chromosomes and specific areas of human chromosomes 1, 3, and 10. Potentially these specific regions of cross hybridisation may be linked to FSHD1B. To examine this possiblity we have carried out linkage studies in our largest FSHD1B family. In this paper we exclude these areas of specific cross hybridisation as disease loci for FSHD1B.

Nitric oxide stimulates ADP ribosylation of actin in association with the inhibition of actin polymerization in human neutrophils

In these studies we provide conclusive evidence that (beta/gamma) actin present in human neutrophils is a substrate for nitric oxide (NO)-dependent ADP ribosylation and that this modification is associated with the inhibition of actin polymerization. A 43-kDa substrate for NO-dependent ADP ribosylation was identified as actin by four methods: (1) comigration with the botulinum C2 toxin substrate by two-dimensional gel electrophoresis (pI 5.2), (2) identity between the peptide map generated by V8 protease digestion of the NO and botulinum C2 substrates, (3) immunoprecipitation with antiactin antibodies, and (4) the ability of NO to ADP ribosylate purified neutrophil G-actin in the presence of plasma membrane cofactors. Because the ADP ribosylation of actin by the botulinum C2 toxin is known to inhibit F-actin polymerization, we examined the effect of NO on actin assembly. Flow cytometry revealed that NO inhibited formyl-methionine-leucine-phenylalanine (fMLP)-dependent (30 s at 37 degrees C) F-actin formation (108 +/- 8 vs. 89 +/- 6 relative fluorescence units, P < .02). These results were confirmed by quantification of F-actin formation by gel scanning (10% sodium dodecyl sulfate gel, Coomassie, and densitometry): pretreatment of polymorphonuclear leukocytes with NO resulted in a reduction of fMLP-induced, cytoskeletal-associated F-actin, which was accompanied by an increase of Triton-soluble G-actin. NO also inhibited F-actin formation, as observed by means of rhodamine phalloidin staining of neutrophils adherent to a fibronectin-coated surface. This effect was accompanied by a dose-dependent inhibition of neutrophil adherence in NO-treated cells. The data indicate that NO inhibits cytoskeletal assembly and adherence in human neutrophils in association with the ADP ribosylation of actin.