Appendiceal mucinous neoplasm in adolescence: Diagnosis, management, and surveillance.

This case report describes a 17-year-old patient with a low-grade appendiceal mucinous neoplasm. The patient presented with non-bloody diarrhea, abdominal pain, and weight loss. A colonoscopy revealed a cecal polypoid mass that required laparoscopic surgery. The residual appendix was dilated with myxoglobulosis and histopathology confirmed the diagnosis of a low-grade appendiceal mucinous neoplasm staged pT3Nx. The potential risk of pseudomyxoma peritonei is a serious complication of these tumors. Surveillance plans include computed tomography abdomen and pelvis, and tumor markers every 6 months for the next 2 years. This case highlights the importance of considering appendiceal malignancy in patients with abdominal pain and weight loss, despite the rarity of the disease. It also emphasizes the need for careful monitoring due to the possible complications associated with these tumors. Treatment and prognosis for appendiceal neoplasms depend on the histopathologic characteristics, tumor-nodes-metastasis stage, tumor grade, and presence of peritoneal disease.

Use of monoclonal antibodies in cancer immunotherapy: types and mechanisms of action.

Immunotherapy is one of the most innovative treatments in the current field of oncology and consists of stimulating the immune system to eliminate tumoral cells. Monoclonal antibodies (mAbs) are glycoproteins secreted by B-cells capable of recognizing and neutralizing foreign organisms or antigens. Structurally, they are composed of two heavy and two light chains. The generation of therapeutic mAbs is one of the most developed and fastest-growing areas of the biotechnological and pharmaceutical industries and is an important adjunct to cancer therapy. Several antibodies have been approved for human administration and can be mouse-derived, chimeric, humanized, or fully human. mAbs main mechanism of action includes the lysis of the tumoral cells through inducing apoptosis, phagocytosis, complement activation, or signaling inhibition.

La inmunoterapia es un tratamiento innovador para la oncología actual, que consiste en la estimulación del sistema inmunitario para la eliminación de las células tumorales. Los anticuerpos monoclonales (mAbs) son glicoproteínas secretadas por los linfocitos B, capaces de reconocer y neutralizar organismos extraños o antígenos. Estructuralmente se componen de dos cadenas pesadas y dos cadenas ligeras. La generación de mAbs terapéuticos es una de las áreas de mayor crecimiento en la industria biotecnológica y farmacéutica y representa un complemento importante en la terapia del cáncer. Existen diversos mAbs que han sido aprobados para su administración en humanos, y pueden ser derivados de ratón, quiméricos, humanizados o completamente humanos. Los mecanismos de acción consisten principalmente en la lisis de las células tumorales a través de la inducción de la apoptosis, fagocitosis, activación del complemento o inhibición de la señalización celular.

Use of monoclonal antibodies in cancer immunotherapy: types and mechanisms of action / Uso de anticuerpos monoclonales en la inmunoterapia del cáncer: tipos y mecanismos de acción

Abstract Immunotherapy is one of the most innovative treatments in the current field of oncology and consists of stimulating the immune system to eliminate tumoral cells. Monoclonal antibodies (mAbs) are glycoproteins secreted by B-cells capable of recognizing and neutralizing foreign organisms or antigens. Structurally, they are composed of two heavy and two light chains. The generation of therapeutic mAbs is one of the most developed and fastest-growing areas of the biotechnological and pharmaceutical industries and is an important adjunct to cancer therapy. Several antibodies have been approved for human administration and can be mouse-derived, chimeric, humanized, or fully human. mAbs main mechanism of action includes the lysis of the tumoral cells through inducing apoptosis, phagocytosis, complement activation, or signaling inhibition.

Resumen La inmunoterapia es un tratamiento innovador para la oncología actual, que consiste en la estimulación del sistema inmunitario para la eliminación de las células tumorales. Los anticuerpos monoclonales (mAbs) son glicoproteínas secretadas por los linfocitos B, capaces de reconocer y neutralizar organismos extraños o antígenos. Estructuralmente se componen de dos cadenas pesadas y dos cadenas ligeras. La generación de mAbs terapéuticos es una de las áreas de mayor crecimiento en la industria biotecnológica y farmacéutica y representa un complemento importante en la terapia del cáncer. Existen diversos mAbs que han sido aprobados para su administración en humanos, y pueden ser derivados de ratón, quiméricos, humanizados o completamente humanos. Los mecanismos de acción consisten principalmente en la lisis de las células tumorales a través de la inducción de la apoptosis, fagocitosis, activación del complemento o inhibición de la señalización celular.

Esophageal polyp in a teenage boy with eosinophilic esophagitis.

The association of eosinophilic esophagitis and esophageal polyps has been reported in the literature but remains a rare finding in both adults and children. The patient in this case report presented with progressively worsening dysphagia secondary to eosinophilic esophagitis and an esophageal polyp. Dysphagia is always abnormal, and endoscopic evaluation is essential. Dysphagia is a well-known symptom in patients with eosinophilic esophagitis. While esophageal polyps as a whole are less common in the pediatric population, they should not be overlooked as a possible cause of dysphagia and esophageal obstruction.

Colitis ulcerativa fulminante complicada con megacolon tóxico / Fulminant ulcerative colitis complicated with toxic megacolon

Presentamos un caso de abdomen agudo secundario a megacolon tóxico perforado como debut de colitis ulcerativa que requirió múltiples intervenciones quirúrgicas y estancia prolongada en la unidad de cuidados intensivos. El megacolon tóxico es una complicación infrecuente y potencialmente fatal de la colitis ulcerativa, siendo más raro aún como debut en un paciente sin antecedentes y con solo un factor de riesgo identificado, considerándolo una oportunidad para compartir su estudio y abordaje. El diagnóstico de megacolon tóxico se configura de acuerdo con los criterios propuestos por Jalan. Aunque el tratamiento inicial es médico con corticoterapia endovenosa, un porcentaje importante de pacientes precisará abordaje quirúrgico.

We present a case of acute abdomen secondary to perforated toxic megacolon in a patient with new-onset ulcerative colitis (UC) that required multiple surgical interventions and prolonged intensive care unit stay. Toxic megacolon is a rare but potentially fatal complication of UC, being even rarer in new-onset UC in a patient with no history and only one risk factor identified, considering this an opportunity to share its study and approach. The diagnosis of toxic megacolon is based on the criteria proposed by Jalan. Although the initial treatment is medical therapy with intravenous corticosteroids, surgical management is necessary for a significant majority of patients.

Tratamiento de ortopedia en niños especiales / Orthopedic treatment in special children

Secuencia de tratamiento con ortopedia maxilar en una niña con síndrome de Down que presenta una mesiorrelación, debido a un maxilar superior chico y retruído y el maxilar inferior grande, con mordida invertida anterior y bilateral, alteraciones funcionales y tipo de crecimiento rotacional anterior, microdoncia y agenesias múltiples (AU)

Treatment with maxillary orthopedics in a girl with Down´s syndrome who presents a mesial relation due to a small and retruded superior maxillary and a big inferior maxillary, with inverted palatal and bilateral bite, functional alterations and palatal rotational growth, microdontia and multiple agenesis (AU)

Revitalizing pathology laboratories in a gastrointestinal pathophysiology course using multimedia and team-based learning techniques.

In 2008, we changed the gastrointestinal pathology laboratories in a gastrointestinal pathophysiology course to a more interactive format using modified team-based learning techniques and multimedia presentations. The results were remarkably positive and can be used as a model for pathology laboratory improvement in any organ system. Over a two-year period, engaging and interactive pathology laboratories were designed. The initial restructuring of the laboratories included new case material, Digital Atlas of Video Education Project videos, animations and overlays. Subsequent changes included USMLE board-style quizzes at the beginning of each laboratory, with individual readiness assessment testing and group readiness assessment testing, incorporation of a clinician as a co-teacher and role playing for the student groups. Student responses for pathology laboratory contribution to learning improved significantly compared to baseline. Increased voluntary attendance at pathology laboratories was observed. Spontaneous student comments noted the positive impact of the laboratories on their learning. Pathology laboratory innovations, including modified team-based learning techniques with individual and group self-assessment quizzes, multimedia presentations, and paired teaching by a pathologist and clinical gastroenterologist led to improvement in student perceptions of pathology laboratory contributions to their learning and better pathology faculty evaluations. These changes can be universally applied to other pathology laboratories to improve student satisfaction.

Persistent psychological or physical symptoms following endoscopic procedures: an unrecognized post-endoscopy adverse event.

BACKGROUND: Depression and post-traumatic stress disorder have been described after surgical procedures, but not after gastrointestinal endoscopy. AIMS: The aim of our retrospective survey was to determine if new-onset, persistent (>1 month) psychological and/or physical symptoms develop after gastrointestinal endoscopy. We also sought to assess how endoscopy teams respond to patient discomfort during the procedure. METHODS: We conducted in-person interviews among 57 gastroenterologists and endoscopy nurses at two large academic medical centers and a community hospital. Response rate was 81% (57/70). RESULTS: Among gastroenterologists surveyed, 62% had encountered at least one patient with persistent new-onset unexplained physical symptoms, and 48% had encountered at least one patient with persistent new-onset psychological symptoms that started after an endoscopic procedure. A total of 44 such patients were identified, and most were women between 20 and 40 years of age. Common new symptoms that developed after gastrointestinal endoscopy were abdominal discomfort, diarrhea, globus sensation, anxiety disorder and depression. Duration of these symptoms was 1 month to 3 years. Gastroenterologists reported that 4% and endoscopy nurses reported that 10% of patients undergoing endoscopy gestured or requested that the endoscopic procedure be prematurely stopped due to discomfort. Only 11/29 (38%) physicians reported that while obtaining consent for endoscopic procedures, they routinely discuss the possibility of stopping prematurely if the patient becomes uncomfortable. Conclusion Persistent physical or psychological symptoms can develop in some patients after endoscopic procedures.

Using medical students to enhance curricular integration of cross-cultural content.

We hypothesized that an interested medical student group would be helpful in reviewing tutorial cases and giving relevant feedback on the curricular integration of cross-cultural content using case triggers in a preclinical gastrointestinal pathophysiology course. Self-selected student leaders (n = 9) reviewed pre-existing problem-based learning tutorial cases (n = 3) with cross-cultural triggers, and provided narrative feedback to course faculty. The cases were modified and used for the entire class in the following 2 years. Participating course students' comments and teaching faculty feedback were also noted. Outcomes were a change in case content, student global evaluations of the course, and self-reported faculty comfort with teaching the cases. All three tutorial cases were reviewed by a separate group of 2-3 students. Major and minor revisions were made to each case based on the student feedback. These cases were used in 2007 and 2008 and were the major change to the course during that time. Overall course evaluation scores improved significantly from 2006 to 2008 (p = 0.000). Tutors (n = 22 in 2007; n = 23 in 2008) expressed relief during tutor meetings that students had reviewed the cases. A general framework for eliciting student feedback on problem-based cases was developed. Student feedback, consisting of self-selected students' case reviews and solicited course and tutor comments, added value to a curricular reform to improve the integration of cross-cultural content into a problem-based learning curriculum. Our study underscores the fundamental link between teachers and students as partners in curricular development.

Integration of racial, cultural, ethnic, and socioeconomic factors into a gastrointestinal pathophysiology course.

BACKGROUND & AIMS: Our study describes a faculty development program to encourage the integration of racial, cultural, ethnic, and socioeconomic factors such as obesity, inability to pay for essential medications, the use of alternative medicine, dietary preferences, and alcoholism in a gastrointestinal pathophysiology course. METHODS: We designed a 1-hour faculty development session with longitudinal reinforcement of concepts. The session focused on showing the relevance of racial, ethnic, cultural, and socioeconomic factors to gastrointestinal diseases, and encouraged tutors to take an active and pivotal role in discussion of these factors. The study outcome was student responses to course evaluation questions concerning the teaching of cultural and ethnic issues in the course as a whole and by individual tutorials in 2004 (pre-faculty development) and in 2006 to 2008 (post-faculty development). RESULTS: Between 2004 and 2008, the proportion of students reporting that "Issues of culture and ethnicity as they affect topics in this course were addressed" increased significantly (P = .000). From 2006 to 2008, compared with 2004, there was a significant increase in the number of tutors who "frequently" taught culturally competent care according to 60% or greater of their tutorial students (P = .003). The tutor's age, gender, prior tutor experience, rank, and specialty did not significantly impact results. CONCLUSIONS: An innovative faculty development session that encourages tutors to discuss racial, cultural, ethnic, and socioeconomic issues relevant to both care of the whole patient and to the pathophysiology of illness is both effective and applicable to other preclinical and clinical courses.

Evidence of increased flux to n-6 docosapentaenoic acid in phospholipids of pancreas from cftr-/- knockout mice.

An association has been reported between alterations in fatty acid metabolism and cystic fibrosis (CF). We hypothesized that these alterations are specific for a particular lipid component(s) and are the result of a specific metabolic defect. The different lipid classes were examined for fatty acid changes by using pancreatic homogenates and primary cultures of pancreatic acini from cftr(-/-) (CF) and wild-type mice. Lipid classes and phospholipids were separated by aminopropyl column chromatography and high-performance liquid chromatography, and fatty acid methyl esters were analyzed. The results indicate that in CF mice (1) linoleate was decreased in phospholipids but not in neutral lipids; (2) there was an increase in dihomo-gamma-linolenate and in docosapentaenoate, the terminal fatty acid of the n-6 pathway, in total lipids and total phospholipids, but not in the neutral lipid class; and (3) the docosapentaenoate (n-6)/docosahexaenoate (n-3) ratio was significantly elevated in neutral phospholipids. This suggests an enhanced flux through the n-6 pathway beyond arachidonate. This study provides a more in-depth understanding of the fatty acid alterations found in CF, as reflected by the cftr(-/-) mouse model.

Liver and skeletal muscle lipids have differing fatty acid profiles in short-gut rats fed via parenteral nutrition.

BACKGROUND: In short-gut rats, we showed marked abnormalities in plasma lipid fatty acids using parenteral nutrition (PN) with lipid vs sham surgery rats. This suggests that either sensing or metabolism of parenteral lipid is abnormal in malabsorption. The goal of this study was to determine fatty acid profiles in skeletal muscle and liver in short-gut rats treated with PN compared with sham rats. METHODS: Sprague-Dawley rats underwent laparotomy and massive small bowel resection (or sham surgery). Rats (n = 32, 16 sham, 16 short gut) were randomly assigned to PN with lipid or fat-free PN. After 5 days, weight loss was similar in all groups, and mixed hindlimb skeletal muscle and liver were biopsied. RESULTS: We found marked differences between liver and skeletal muscle. In livers of short-gut animals, 22:4omega6, 22:5omega6, and 22:6omega3 were higher (all p < .05) than in sham. In skeletal muscle, short gut had no effect on fatty acid profiles. In liver, fat-free PN led to significant increases in 20:3omega6, 22:4omega6, 22:5omega6, 20:3omega9, 20:5omega3, 22:6omega3, and triene/tetraene ratio (all p < .05) compared with feeding PN with lipid, irrespective of short gut. In muscle, levels of the distal long-chain fatty acid metabolites and triene/tetraene ratio were minimally affected by nutrition. Serum glucose and insulin concentrations were similar in all 4 groups. CONCLUSIONS: Both the presence of short gut and type of PN led to increases in distal metabolites of fatty acids on omega:3 and omega:6 pathway in liver phospholipids but not in skeletal muscle during short-term PN feeding in rats.

Ethanol administration to cystic fibrosis knockout mice results in increased fatty acid ethyl ester production.

BACKGROUND: Fatty acid ethyl esters (FAEE) are nonoxidative ethanol metabolites shown to produce toxic effects in the liver and pancreas in vivo and in vitro. Because alcohol-induced chronic pancreatitis is associated with mutations in the gene responsible for cystic fibrosis (CFTR), we hypothesized that CFTR dysfunction leads to increased levels of these toxic nonoxidative ethanol metabolites following alcohol administration. METHODS: Cystic fibrosis (CF) and wild-type (WT) mice were injected intraperitoneally with 1, 2, or 3 g/kg of 50% ethanol. Mice were sacrificed and the liver and pancreas removed for FAEE analysis. RESULTS: The mean FAEE concentration (pmol/g) detected in the liver of cftr mice following injection with 2 g/kg of ethanol was significantly greater than the amount detected in WT (p < 0.005). A similar trend in FAEE concentration was seen in the pancreas, but the difference was not statistically different. In both the liver and pancreas, analysis of individual FAEE species demonstrated a selective increase in ethyl oleate. CONCLUSION: These data show an association between CFTR dysfunction and qualitative and quantitative changes in FAEE in liver and pancreas upon ethanol exposure.

Decreased expression of peroxisome proliferator activated receptor gamma in cftr-/- mice.

Some of the pathological manifestations of cystic fibrosis are in accordance with an impaired expression and/or activity of PPARgamma. We hypothesized that PPARgamma expression is altered in tissues lacking the normal cystic fibrosis transmembrane regulator protein (CFTR). PPARgamma mRNA levels were measured in colonic mucosa, ileal mucosa, adipose tissue, lung, and liver from wild-type and cftr-/- mice by quantitative RT-PCR. PPARgamma expression was decreased twofold in CFTR-regulated tissues (colon, ileum, and lung) from cftr-/- mice compared to wild-type littermates. In contrast, no differences were found in fat and liver. Immunohistochemical analysis of PPARgamma in ileum and colon revealed a predominantly nuclear localization in wild-type mucosal epithelial cells while tissues from cftr-/- mice showed a more diffuse, lower intensity labeling. A significant decrease in PPARgamma expression was confirmed in nuclear extracts of colon mucosa by Western blot analysis. In addition, binding of the PPARgamma/RXR heterodimer to an oligonucletotide containing a peroxisome proliferator responsive element (PPRE) was also decreased in colonic mucosa extracts from cftr-/- mice. Treatment of cftr-/- mice with the PPARgamma ligand rosiglitazone restored both the nuclear localization and binding to DNA, but did not increase RNA levels. We conclude that PPARgamma expression in cftr-/- mice is downregulated at the RNA and protein levels and its function diminished. These changes may be related to the loss of function of CFTR and may be relevant to the pathogenesis of metabolic abnormalities associated with cystic fibrosis in humans.

Oral docosahexaenoic acid given to pregnant mice increases the amount of surfactant in lung and amniotic fluid in preterm fetuses.

OBJECTIVE: Our purpose was to determine whether docosahexaenoic acid increased surfactant production, as reflected by increased dipalmitoyl phosphatidylcholine, in mouse fetal lung and amniotic fluid. STUDY DESIGN: On day 9.5 of gestation, pregnant mice were given docosahexaenoic acid orally at 0, 5, 10, or 20 mg per day and were killed at day 16.5 (preterm) and day 19.5 (term) of gestation. Dipalmitoyl phosphatidylcholine was measured in fetal lung homogenates and amniotic fluid by high-performance thin-layer chromatography. RESULTS: Dipalmitoyl phosphatidylcholine values in lung were 0.22 +/- 0.27 microg/mg of total protein in preterm versus 1.96 +/- 0.57 microg/mg in term control fetuses. Pretreatment with 5, 10, or 20 mg docosahexaenoic acid increased dipalmitoyl phosphatidylcholine levels in preterm fetuses to 1.20 +/- 0.75, 1.60 +/- 0.67, and 3.28 +/- 0.44 microg/mg of protein, respectively. A similar trend was observed in amniotic fluid in which dipalmitoyl phosphatidylcholine levels were 1.86 +/- 3.70 microg/mL in preterm fetuses at baseline and increased to 7.81 +/- 1.21, 16.83 +/- 1.62 and 22.72 +/- 3.44 microg/mL after pretreatment for 7 days with 5, 10, and 20 mg docosahexaenoic acid (P<.05 compared to untreated mice). Dipalmitoyl phosphatidylcholine levels in amniotic fluid were 24.46 +/- 10.3 microg/mL in term control mice. CONCLUSION: The oral administration of docosahexaenoic acid to pregnant mice during pregnancy can induce dipalmitoyl phosphatidylcholine production and secretion, which is the major lipid component of surfactant.

Induction of colitis in cftr-/- mice results in bile duct injury.

It is unknown why some patients with inflammatory bowel disease develop primary sclerosing cholangitis. We have recently shown that patients with primary sclerosing cholangitis have an increased prevalence of mutations in the gene responsible for cystic fibrosis (CFTR) compared with individuals with inflammatory bowel disease alone. Our aim was to examine whether induction of colitis by oral dextran leads to bile duct injury in mice heterozygous or homozygous for mutations in CFTR. The effect of oral administration of docosahexaenoic acid to correct a fatty acid imbalance associated with cystic fibrosis was also examined to determine whether this would prevent bile duct inflammation. Wild-type mice and mice heterozygous and homozygous for CFTR mutations were given dextran orally for 14 days to induce colitis. Bile duct injury was quantitated by blinded histological scoring and measurement of serum alkaline phosphatase activity. The effect of pretreatment with docosahexaenoic acid for 7 days was examined. Treatment of mice with 100 mg dextran/day for 9 days followed by 85 mg/day for 5 days resulted in a significant increase in bile duct injury as determined by histological scoring in homozygous cystic fibrosis mice compared with wild-type mice (P = 0.005). The bile duct injury seen in cystic fibrosis mice was reflected in a threefold increase in serum alkaline phosphatase (P = 0.0006). Pretreatment with oral docosahexaenoic acid decreased both histological evidence of bile duct injury and serum alkaline phosphatase levels. In the setting of colitis, loss of CFTR function leads to bile duct injury.

Abnormal regulation of serum lipid fatty acid profiles in short gut rats fed parenteral nutrition with lipid.

Despite absence of essential fatty acid deficiency (EFAD), increases in arachidonic acid to linoleic acid ratios occur in serum phospholipid of patients treated with chronic total parenteral nutrition (TPN). The parenteral lipid component of TPN contains abundant linoleate; thus low phospholipid linoleate may reflect increased conversion to arachidonate. Arachidonic acid excess has been associated with a proinflammatory milieu through increased eicosanoid production and might contribute to the increases in inflammatory markers seen in home TPN patients. We investigated fatty acid metabolism in a rodent model of malabsorption. We hypothesized that short gut rats would metabolize parenteral lipid differently from intact rats. We performed laparotomy and 80% small bowel resection (or sham surgery) in rats. Sixteen sham and 16 short gut rats were randomly assigned to TPN with lipid or fat-free TPN. After 5 days, weight loss was similar in all groups. Analysis of serum phospholipids demonstrated that 20:3omega9 (eicosatrienoic acid) was relatively increased in fat-free TPN groups, irrespective of surgery type, as were distal very long chain omega3 class fatty acids, as anticipated. Uniquely, both nutrition (TPN/lipid v fat-free TPN) and surgery type (sham v short gut) were significant in determining arachidonic acid levels. Relatively elevated arachidonate occurred in both groups of fat-free rats, suggesting increased Delta6 and/or Delta5 desaturase activity, as expected. In contrast, giving TPN/lipid lowered arachidonate (suggesting appropriately downregulated desaturases) in sham animals, but not in short gut animals. Ratios of arachidonic and di-homo-gamma-linolenic to linoleic acids further suggested increased turnover of precursor omega6 to arachidonic acid in short gut rats given lipid compared with the other groups. These preliminary data show that intravenous (IV) lipid gave rise to serum lipid fatty acid profiles that differed in short gut and sham rats. The short gut rat may have a heightened hepatic desaturase activity, inappropriate for the quantity of linoleic acid provided parenterally. Therefore, the short gut rat is an appropriate model to study further arachidonic acid excess in home TPN patients.

Association of cystic fibrosis with abnormalities in fatty acid metabolism.

BACKGROUND: Patients with cystic fibrosis have altered levels of plasma fatty acids. We previously demonstrated that arachidonic acid levels are increased and docosahexaenoic acid levels are decreased in affected tissues from cystic fibrosis-knockout mice. In this study we determined whether humans with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene have a similar fatty acid defect in tissues expressing CFTR. METHODS: Fatty acids from nasal- and rectal-biopsy specimens, nasal epithelial scrapings, and plasma were analyzed from 38 subjects with cystic fibrosis and compared with results in 13 obligate heterozygotes, 24 healthy controls, 11 subjects with inflammatory bowel disease, 9 subjects with upper respiratory tract infection, and 16 subjects with asthma. RESULTS: The ratio of arachidonic to docosahexaenoic acid was increased in mucosal and submucosal nasal-biopsy specimens (P<0.001) and rectal-biopsy specimens (P=0.009) from subjects with cystic fibrosis and pancreatic sufficiency and subjects with cystic fibrosis and pancreatic insufficiency, as compared with values in healthy control subjects. In nasal tissue, this change reflected an increase in arachidonic acid levels and a decrease in docosahexaenoic acid levels. In cells from nasal mucosa, the ratio of arachidonic to docosahexaenoic acid was increased in subjects with cystic fibrosis (P<0.001), as compared with healthy controls, with values in obligate heterozygotes intermediate between these two groups (P<0.001). The ratio was not increased in subjects with inflammatory bowel disease. Subjects with asthma and those with upper respiratory tract infection had values intermediate between those in subjects with cystic fibrosis and those in healthy control subjects. CONCLUSIONS: These data indicate that alterations in fatty acids similar to those in cystic fibrosis-knockout mice are present in CFTR-expressing tissue from subjects with cystic fibrosis.

Acute regulation of the SLC26A3 congenital chloride diarrhoea anion exchanger (DRA) expressed in Xenopus oocytes.

Mutations in the human SLC26A3 gene, also known as down-regulated in adenoma (hDRA), cause autosomal recessive congenital chloride-losing diarrhoea (CLD). hDRA expressed in Xenopus oocytes mediated bidirectional Cl--Cl- and Cl--HCO3- exchange. In contrast, transport of oxalate was low, and transport of sulfate and of butyrate was undetectable. Two CLD missense disease mutants of hDRA were nonfunctional in oocytes. Truncation of up to 44 C-terminal amino acids from the putatively cytoplasmic C-terminal hydrophilic domain left transport function unimpaired, but deletion of the adjacent STAS (sulfate transporter anti-sigma factor antagonist) domain abolished function. hDRA-mediated Cl- transport was insensitive to changing extracellular pH, but was inhibited by intracellular acidification and activated by NH4+ at acidifying concentrations. These regulatory responses did not require the presence of either hDRA's N-terminal cytoplasmic tail or its 44 C-terminal amino acids, but they did require more proximate residues of the C-terminal cytoplasmic domain. Although only weakly sensitive to inhibition by stilbenes, hDRA was inhibited with two orders of magnitude greater potency by the anti-inflammatory drugs niflumate and tenidap. cAMP-insensitive Cl--HCO3- exchange mediated by hDRA gained modest cAMP sensitivity when co-expressed with cystic fibrosis transmembrane conductance regulator (CFTR). Despite the absence of hDRA transcripts in human cell lines derived from CFTR patients, DRA mRNA was present at wild-type levels in proximal colon and nearly so in the distal ileum of CFTR(-/-) mice. Thus, pharmacological modulation of DRA might be a useful adjunct treatment of cystic fibrosis.

Characterization of LPS-induced lung inflammation in cftr-/- mice and the effect of docosahexaenoic acid.

The mechanism by which Pseudomonas causes excessive inflammation in the cystic fibrosis lung is unclear. We have reported that arachidonic acid is increased and docosahexaenoic acid (DHA) decreased in lung, pancreas, and ileum from cftr-/- mice. Oral DHA corrected this defect and reversed the pathology. To determine which mediators regulate inflammation in lungs from cftr-/- mice and whether inhibition occurs with DHA, cftr-/- and wild-type (WT) mice were exposed to aerosolized Pseudomonas lipopolysaccharide (LPS). After 2 days of LPS, tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-2, and KC levels in bronchoalveolar lavage fluid were increased in cftr-/- compared with WT mice and not suppressed by pretreatment with oral DHA. Neutrophil levels were not different between cftr-/- and WT mice. After 3 days of aerosolized LPS, neutrophil concentration, TNF-alpha, and the eicosanoids 6-keto-PGF1alpha, PGF2alpha, PGE2, and thromboxane B2 were all increased in bronchoalveolar lavage fluid from cftr-/- mice compared with WT controls. Oral DHA had no significant effect on TNF-alpha levels in cftr-/- mice. In contrast, neutrophils and eicosanoids were decreased in cftr-/- but not in WT mice treated with DHA, indicating that the effects of DHA on these inflammatory parameters may be related to correction of the membrane lipid defect.