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Biomedical subjects

E Cutz

Publications and source records attributed to E Cutz.

At least 19 recordsLinked to original sources

Massive hemoptysis in an 11-year-old girl with isolated pulmonary arteritis.

A 10-year-old girl developed recurrent bouts of massive hemoptysis over a 9-month period. No obvious bleeding source was detected. Her pulmonary angiogram showed a pulmonary aneurysm of the second branch of the left main pulmonary artery as well as widespread irregularities of the pulmonary arteries including areas of stenosis and pruning. Elective embolization of the aneurysm did not control hemoptysis and emergency left upper lobectomy had to be performed. Histology showed large artery wall injury with acute leucocytoclastic inflammation, fibrinoid necrosis, granulomatous inflammation, and ectasia of vessel wall. This combination of abnormalities has not been described to date and represents the first case of isolated pulmonary arteritis in children prior to puberty.

Aneurysm↗

Oxygen sensing in neuroepithelial and adrenal chromaffin cells.

Oxygen sensing and initiation of appropriate physiological responses to hypoxia are crucial for survival. The molecular identity of the sensor has generally sparked considerable interest and controversy in O2-sensitive cells. In mammals, pulmonary neuroepithelial bodies (NEBs) and adrenal chromaffin cells (AMCs) are O2 sensitive, particularly during the transition from intrauterine to air-breathing life. In NEBs, there is good evidence that the O2 sensor is a plasma membrane-bound NADPH oxidase which during hypoxia, signals K+ channel inhibition, membrane depolarization and neurosecretion via changes in reactive oxygen species (ROS) (e.g. H2O2). Accordingly, hypoxic sensitivity is lost in NEBs from transgenic mice deficient in the gp91(phox) subunit of NADPH oxidase; it is, however, retained in neonatal AMCs from these transgenic mice. A search for the O2 sensor in neonatal rat AMCs suggests a role for the mitochondrial electron transport chain. For example, the complex I blocker, rotenone (1 microM), mimics hypoxia in causing K+ channel inhibition and ATP secretion, and occludes hypoxic sensitivity. The evidence is consistent with hypoxia and rotenone acting via a decrease in ROS. In contrast, the complex IV blocker cyanide (2 mM) did not mimic the effects of hypoxia. We propose thatchanges in ROS serve as a common link between the O2 sensor and secretion in perinatal NEBs and chromaffin cells. However, the subcellular localization of the O2 sensor appears to be different between these two cell types.

Adrenal Glands↗

Neonatal diabetes, with hypoplastic pancreas, intestinal atresia and gall bladder hypoplasia: search for the aetiology of a new autosomal recessive syndrome.

AIMS/HYPOTHESIS: Neonatal diabetes is a rare disease with several identified molecular aetiologies. Despite associations with other malformations, neonatal diabetes with intestinal and biliary anomalies has not been described. The current study aims to describe a new syndrome, and to examine a possible link with one of three genes known to cause neonatal diabetes. METHODS: Five clinical cases are described. Immunohistochemical staining for pancreatic islet hormones was performed on three of the infants. DNA from one infant was analysed for abnormalities of the PLAGL-1 (ZAC), glucokinase and PDX-1 (IPF-1) genes. RESULTS: Five infants (two sibling pairs from two families, and an isolated case) presented with neonatal diabetes, hypoplastic or annular pancreas, jejunal atresia, duodenal atresia and gall bladder aplasia or hypoaplasia. One sibling pair was born to consanguineous parents. One patient with a milder form is surviving free of insulin. Four children died in the first year of life despite aggressive medical management. Pancreatic immunohistochemistry revealed few scattered chromogranin-A-positive cell clusters but complete absence of insulin, glucagon and somatostatin. Exocrine histology was variable. In one case from the consanguineous family, molecular analysis showed no duplication or uniparental isodisomy of PLAGL-1 at 6q24, no contiguous gene deletion involving the glucokinase gene, and no mutation in the coding sequences or splice sites of PDX-1. CONCLUSIONS/INTERPRETATION: This combination of multiple congenital abnormalities has not been previously described and probably represents a new autosomal recessive syndrome involving a genetic abnormality that interferes with normal islet development and whose aetiology is as yet unknown.

Abnormalities, Multiple↗

Gastral antral biopsy in the differentiation of pediatric colitides.

OBJECTIVES: Differentiation of Crohn's disease (CD) from ulcerative colitis (UC) is problematic, primarily when inflammation is confined to the colon. In a historical cohort study, we evaluated the usefulness of baseline gastric antral biopsies in the differentiation of pediatric chronic colitides. METHODS: During initial investigation for suspected inflammatory bowel disease, 39 children and adolescents with colitis but normal small bowel radiography underwent pretreatment upper endoscopy concurrently with colonoscopy. Two reviewers assigned a colonoscopic diagnosis (colonic CD, UC, or indeterminate colitis) based on the macroscopic and microscopic appearances of the colonic mucosa. Antral histological findings were compared between groups using Fisher's exact test. RESULTS: Five (14%) of colonoscopic diagnoses (four indeterminate, one UC) were changed to CD by the finding of granulomatous inflammation in antral biopsies. Nonspecific antral gastritis was found in similar proportions of children and adolescents with Crohn's colitis and UC (92% vs 75%). Focal antral gastritis was more common in patients with Crohn's colitis than UC (52% vs 8%). CONCLUSIONS: Nonspecific antral gastritis is common in all forms of chronic colitis. Nevertheless, upper gastrointestinal endoscopy with biopsy is useful in the differentiation of inflammatory bowel disease confined to the colon, particularly when colonoscopic findings are indeterminate.

Adolescent↗

Hypoxia-induced secretion of serotonin from intact pulmonary neuroepithelial bodies in neonatal rabbit.

We examined the effects of hypoxia on the release of serotonin (5-HT) from intact neuroepithelial body cells (NEB), presumed airway chemoreceptors, in rabbit lung slices, using amperometry with carbon fibre microelectrodes. Under normoxia (P(O2) ~155 mmHg; 1 mmHg approximately 133 Pa), most NEB cells did not exhibit detectable secretory activity; however, hypoxia elicited a dose-dependent (P(O2) range 95-18 mmHg), tetrodotoxin (TTX)-sensitive stimulation of spike-like exocytotic events, indicative of vesicular amine release. High extracellular K(+) (50 mM) induced a secretory response similar to that elicited by severe hypoxia. Exocytosis was stimulated in normoxic NEB cells after exposure to tetraethylammonium (20 mM) or 4-aminopyridine (2 mM). Hypoxia-induced secretion was abolished by the non-specific Ca(2+) channel blocker Cd(2+) (100 microM). Secretion was also largely inhibited by the L-type Ca(2+) channel blocker nifedipine (2 microM), but not by the N-type Ca(2+) channel blocker omega-conotoxin GVIA (1 microM). The 5-HT(3) receptor blocker ICS 205 930 also inhibited secretion from NEB cells under hypoxia. These results suggest that hypoxia stimulates 5-HT secretion from intact NEBs via inhibition of K(+) channels, augmentation of Na(+)-dependent action potentials and calcium entry through L-type Ca(2+) channels, as well as by positive feedback activation of 5-HT(3) autoreceptors.

Animals↗

Histological improvement with lamivudine therapy for de novo hepatitis B occurring in an anti-HBs-positive child after bone marrow transplantation.

We describe a 14-year-old bone marrow transplant recipient who was anti-HBs-positive before the procedure and afterwards developed acute infection with hepatitis B virus (HBV). Liver biopsies taken while symptomatic showed portal fibrosis progressing to cirrhosis. The patient responded to lamivudine treatment with HBeAg seroconversion and significant regression of fibrosis. Although the source and timing of HBV exposure remain unclear, the potential for severe hepatitis B infection following bone marrow transplant warrants caution. This case demonstrates that a symptomatic HBV infection can occur in an immunocompromised patient who had originally been anti-HBs-positive.

Adolescent↗

Raffinose improves 24-hour lung preservation in low potassium dextran glucose solution: a histologic and ultrastructural analysis.

BACKGROUND: We have previously shown that the addition of raffinose to low potassium dextran (LPD) preservation solution improves transplanted rat lung function after 24 hours of storage. The mechanisms by which raffinose acts are unclear. The aim of this study was to examine the histologic and ultrastructural correlates of this enhanced pulmonary function after preservation with raffinose. METHODS: In a randomized, blinded study, rat lungs were flushed with LPD, or LPD containing 30 mmol/L of raffinose, and stored for 24 hours at 4 degrees C. Control lungs were flushed with LPD but not stored (n = 5 each group). Changes in postpreservation edema were determined. In addition, lungs were flushed with a trypan blue solution to quantify cell death, and examined using both light and electron microscopy. RESULTS: The LPD lungs gained significantly more weight (25.5%+/-5.5%) compared with raffinose-LPD lungs (5.2%+/-5.3%; p < 0.0001). There were higher percentages of dead cells in the LPD lungs (29%+/-0.3% of total cells) compared with raffinose-LPD lungs (14%+/-1.4%; p < 0.001) and control lungs (0.2%+/-5%; p < 0.001). Control lungs maintained normal ultrastructure, whereas LPD lungs showed a decreased number of intact type II pneumocytes and significant cellular necrosis. Interstitial and alveolar edema with interstitial macrophage infiltration was also observed. Alveolar capillaries were collapsed. In contrast, raffinose-LPD lungs showed only mild alterations such as minimal interstitial edematous expansion, fewer damaged cells, and minimal capillary injury. CONCLUSIONS: Raffinose exerts a cytoprotective effect on pulmonary grafts during preservation, which explains the previously documented improved function. This simple modification of LPD with raffinose may provide clinical benefit in extended pulmonary preservation.

Animals↗

Respiratory control in neonatal mice with NADPH oxidase deficiency.

A membrane bound cytochrome b(558) (NADPH oxidase) is a candidate for the oxygen sensor in pulmonary neuroepithelial bodies (NEBs) - putative airway chemoreceptors. Recent electrophysiological studies on NEB from mice with NADPH oxidase deficiency (OD; gp(91phox) knock-out) have shown lack of response of O(2) sensitive K(+) current to hypoxia challenge compared with wild-type (WT) control mice. To assess the effects of oxidase deficiency on the control of ventilation at the whole animal level, respiratory measurements were conducted under normoxic and hypoxic conditions in neonatal OD mice and compared that with the WT control group. Five-day-old OD mice were faster and shallower breathers during normoxia as well as hypoxia. In addition, the maximum hypoxic ventilatory response of the OD mice was lower than that of the WT control group and the peak increase in minute ventilation (.V(max)-.V(normoxia)) was greater in WT control than the OD mice (P=0.02). Since the lung development and NEB morphology in OD mice were comparable to the WT control mice, the observed differences implicate NADPH oxidase as an O(2) sensor involved in neonatal ventilatory control, possibly modulated via pulmonary NEBs.

Animals↗

Esophagatis and perinatal cytomegalovirus infection.

A 6-week-old male infant presented to hospital with a large upper gastrointestinal hemorrhage. Endoscopic biopsies of his esophagus and duodenum showed cytomegalovirus (CMV) inclusions and CMV early antigen was detected by immunohistochemistry. There were no other signs of congenital CMV infection. This case adds to the clinical spectrum of perinatal CMV infection and may be more common than is currently recognized.

Cytomegalovirus↗

Expression of CFTR and Cl(-) conductances in cells of pulmonary neuroepithelial bodies.

The pulmonary neuroendocrine cell system comprises solitary neuroendocrine cells and clusters of innervated cells or neuroepithelial bodies (NEBs). NEBs figure prominently during the perinatal period when they are postulated to be involved in physiological adaptation to air breathing. Previous studies have documented hyperplasia of NEBs in cystic fibrosis (CF) lungs and increased neuropeptide (bombesin) content produced by these cells, possibly secondary to chronic hypoxia related to CF lung disease. However, little is known about the role of NEBs in the pathogenesis of CF lung disease. In the present study, using a panel of cystic fibrosis transmembrane conductance regulator (CFTR)-specific antibodies and confocal microscopy in combination with RT-PCR, we demonstrate expression of CFTR message and protein in NEB cells of rabbit neonatal lungs. NEB cells expressed CFTR along with neuroendocrine markers. Confocal microscopy established apical membrane localization of the CFTR protein in NEB cells. Cl(-) conductances corresponding to functional CFTR were demonstrated in NEB cells in a fresh lung slice preparation. Our findings suggest that NEBs, and related neuroendocrine mechanisms, likely play a role in the pathogenesis of CF lung disease, including the early stages before establishment of chronic infection and chronic lung disease.

Animals↗

Neuroepithelial bodies in mammalian lung express functional serotonin type 3 receptor.

Serotonin (5-HT) type 3 receptor (5-HT(3)-R) is a ligand-gated ion channel found primarily in the central and peripheral nervous system. We report expression and functional characterization of 5-HT(3)-R in pulmonary neuroepithelial body (NEB) cells. Using nonisotopic in situ hybridization, we demonstrate expression of 5-HT(3)-R mRNA in NEB cells in the lungs of different mammals (hamster, rabbit, mouse, and human). Dual immunocytochemistry (for 5-HT and 5-HT(3)-R) and confocal microscopy localized 5-HT(3)-R on NEB cell plasma membrane from rabbit. The electrophysiological characteristics of 5-HT(3)-R in NEB cells were studied in fresh slices of neonatal hamster lung using the whole cell patch-clamp technique. Application of the 5-HT (5-150 microM) and 5-HT(3)-R agonist 2-methyl-5-HT (5-150 microM) induced inward currents in a concentration-dependent manner. The 5-HT-induced current was blocked (76.5 +/- 5.9%) by the specific 5-HT(3)-R antagonist ICS-205-930 (50 microM), whereas katanserin and p-4-iodo-N-(2-[4-(methoxyphenyl)-1-piperazinyl]ethyl)-N-2-pyridinylbenzamide had minimal effects. Forskolin had no effect on desensitization and amplitude of the 5-HT-induced current. The reduction of Ca(2+) and Mg(2+) in the extracellular solution enhanced the amplitude of the 5-HT-induced current because of slower desensitization. Our studies suggest that 5-HT(3)-R in NEB cells may function as an autoreceptor and may potentially be involved in modulation of hypoxia signaling.

Aminopyridines↗

NADPH oxidase is an O2 sensor in airway chemoreceptors: evidence from K+ current modulation in wild-type and oxidase-deficient mice.

Pulmonary neuroepithelial bodies (NEBs) are presumed airway chemoreceptors that express the putative O(2) sensor protein NADPH oxidase and O(2)-sensitive K(+) channels K(+)(O(2)). Although there is a consensus that redox modulation of K(+)(O(2)) may be a common O(2)-sensing mechanism, the identity of the O(2) sensor and related coupling pathways are still controversial. To test whether NADPH oxidase is the O(2) sensor in NEB cells, we performed patch-clamp experiments on intact NEBs identified by neutral red staining in fresh lung slices from wild-type (WT) and oxidase-deficient (OD) mice. In OD mice, cytochrome b(558) and oxidase function was disrupted in the gp91(phox) subunit coding region by insertion of a neomycin phosphotransferase (neo) gene. Expression in NEB cells of neo mRNA, a marker for nonfunctional gp91(phox), was confirmed by nonisotopic in situ hybridization. In WT cells, hypoxia (pO(2) = 15-20 mmHg; 1 mmHg = 133 Pa) caused a reversible inhibition ( approximately 46%) of both Ca(2+)-independent and Ca(2+)-dependent K(+) currents. In contrast, hypoxia had no effect on K(+) current in OD cells, even though both K(+) current components were expressed. Diphenylene iodonium (1 microM), an inhibitor of the oxidase, reduced K(+) current by approximately 30% in WT cells but had no effect in OD cells. Hydrogen peroxide (H(2)O(2); 0.25 mM), a reactive oxygen species generated by functional NADPH oxidase, augmented K(+) current by >30% in both WT and OD cells; further, in WT cells, H(2)O(2) restored K(+) current amplitude in the presence of diphenylene iodonium. We conclude that NADPH oxidase acts as the O(2) sensor in pulmonary airway chemoreceptors.

4-Aminopyridine↗