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Mandrell BN, Wise M, Schoumacher RA, Pritchard M, West N, Ness KK, Crabtree VM, Merchant TE, Morris B. Excessive daytime sleepiness and sleep-disordered breathing disturbances in survivors of childhood central nervous system tumors. Pediatr Blood Cancer 2012; 58:746-51. [PMID: 22009579 PMCID: PMC3519925 DOI: 10.1002/pbc.23311] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 07/25/2011] [Indexed: 11/08/2022]
Abstract
BACKGROUND Improvements in treatment and management for pediatric central nervous system (CNS) tumors have increased survival rates, allowing clinicians to focus on long-term sequelae, including sleep disorders. The objective of this study was to describe a series of CNS tumor survivors who had sleep evaluations that included polysomnography (PSG) with attention to sleep disorder in relation to the tumor site. PROCEDURE We report on 31 patients who had retrievable reports including an overnight PSG; 17 also underwent multiple sleep latency tests (MSLT) to characterize their sleepiness. RESULTS Mean age at tumor diagnosis was 7.4 years, mean age at sleep referral 14.3 years, and a mean time between tumor diagnosis and sleep referral of 6.9 years. The most common tumor location was the suprasellar region, the most common reason for sleep referral was excessive daytime sleepiness (EDS), and the most common sleep diagnosis was obstructive sleep apnea (n = 14) followed by central sleep apnea (n = 4), hypersomnia due to medical condition (n = 4), and narcolepsy (n = 3). Twenty-six of the 31 subjects were obese/overweight, and among those with the concurrent complaint of EDS, the mean sleep latency on MSLT was 3.16 minutes, consistent with excessive sleepiness. CONCLUSIONS Suprasellar region tumor survivors who are obese or overweight are more likely to have complaints of EDS and are at greater risk of sleep-disordered breathing. Sleep-related symptoms may not be recognized and referral initiated until years after CNS diagnosis. A periodic and thorough sleep history should be taken when caring for CNS tumor survivors.
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Affiliation(s)
- Belinda N Mandrell
- Division of Nursing Research, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
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Shires CB, Anold SL, Schoumacher RA, Dehoff GW, Donepudi SK, Stocks RM. Body mass index as an indicator of obstructive sleep apnea in pediatric Down syndrome. Int J Pediatr Otorhinolaryngol 2010; 74:768-72. [PMID: 20452066 DOI: 10.1016/j.ijporl.2010.03.050] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 03/20/2010] [Accepted: 03/23/2010] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Our objective was to determine if higher body mass index (BMI) increases the likelihood of, obstructive sleep apnea (OSA) in pediatric Down syndrome (DS) patients. METHODS We performed a, retrospective chart review of 63 DS patients evaluated by overnight polysomnography from December 1995 to February 2005. Patients aged less than 2 years were excluded. Remaining patients were grouped, according to presence (n=19) or absence (n=33) of OSA based on apnea hypopnea index (AHI). OSA, and non-OSA DS groups were age matched while blinded to patient attributes other than age and OSA, status. Patients without appropriate age matches were excluded. We recorded various patient information, including age, sex, height, weight, number of apneas, number of hypopneas, respiratory distress index (RDI), apnea-hypopnea index (AHI), lowest oxygen saturation during sleep, mean oxygen saturation, number of arousals per hour, and mean time spent in REM sleep. We calculated BMI using the, standard kg/m(2) formula and converted this into a Z-score. RESULTS Fifty-two DS patients were analyzed with average age of 9.3+/-4.5 years (10.2+/-4.2 in 33 OSA patients, 7.8+/-4.3 in 19 non-OSA patients). There were 28 males and 24 females. The OSA group mean BMI Z-score was 2.09+/-0.94, and the non-OSA group Z-score was 1.4+/-1.40. The Z-scores for BMI were statistically significant between OSA and non-OSA patients with p=0.03 by t-test. CONCLUSIONS When age and sex adjusted, BMI has a statistically significant association with the presence of OSA in Down syndrome patients. The incidence of OSA also increases with increasing age in this population.
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Affiliation(s)
- Courtney B Shires
- Department of Otolaryngology-Head & Neck Surgery, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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Shete MM, Stocks RMS, Sebelik ME, Schoumacher RA. Effects of adeno-tonsillectomy on polysomnography patterns in Down syndrome children with obstructive sleep apnea: a comparative study with children without Down syndrome. Int J Pediatr Otorhinolaryngol 2010; 74:241-4. [PMID: 20097432 DOI: 10.1016/j.ijporl.2009.11.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 11/03/2009] [Accepted: 11/08/2009] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine if adeno-tonsillectomy (T&A) in children with Down syndrome (DS) improves breathing, measured by apnea hypopnea index (AHI), rapid eye movement AHI (REM-AHI) and the lowest oxygen desaturation (SaO2), and sleep disruption, measured by arousal index (ArI) and time spent in stages 1-4 and rapid eye movement (REM) sleep and compare these results with a group of non-DS children with obstructive sleep apnea (OSA). STUDY DESIGN Retrospective chart review at pediatric sleep center. PATIENTS Eleven DS and nine non-DS children underwent pre- and post-T&A polysomnography between 1997 and 2005. OUTCOME MEASURES Pre- and post-T&A polysomnography parameters were compared using paired t-test and independent samples test. RESULTS Mean age in DS group was 101 months and non-DS group was 80 months (64% males in DS and 88% in non-DS group). The average BMI was 29.8 and 27.6 for DS and non-DS group. The total AHI showed significant improvement after T&A but this was not as marked as the non-DS group. REM-AHI and lowest SaO2 did not show significant change in the DS children. The non-DS group showed significant improvement in all respiratory parameters. Both groups showed mild improvement in sleep parameters. With the modest overall improvement, 27% of the DS children required no further treatment. However, 73% required CPAP, BiPAP or oxygen for persistent OSA. CONCLUSION This study supports the fact that T&A in DS children improves some parameters of OSA, however not as markedly as in non-DS children.
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Affiliation(s)
- Mona M Shete
- Otolaryngology & Head and Neck Surgery, University Tennessee Health Science Center, 910 Madison Ave, Suite 429, Memphis, TN 38163, USA.
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Abstract
This is a case report of a 9-year-old boy with new onset stridor 5 days after a choking event. Symptoms would last 5-45 minutes. His stridor was unresponsive to nebulized epinephrine but improved when he relaxed. Otlaryngology examination noted laryngeal irritation that was suggestive of gastroesophageal reflux (GER). Episodic stridor continued, despite treatment for GER, prompting hospitalization. On admission, barium swallow indicated hyperinflation of the left lung and bronchoscopy confirmed the aspiration of food. Within 12 hours of bronchoscopy, his stridor recurred. The recurrence of stridor after bronchoscopy resulted in further evaluation of his upper airway disorder. The true diagnosis was revealed during methacholine challenge. This case illustrates a unique presentation of a common upper respiratory disorder, the need for a high index of suspicion to make the diagnosis, and the importance of the multispecialty approach needed to treat patients with this disorder.
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Affiliation(s)
- Thomas G. Sternberg
- Department of Pediatrics, Le Bonheur Children’s Hospital, University of Tennessee Health Sciences Center, Memphis, Tennessee, USA
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Hinds PS, Yang J, Gattuso JS, Hockenberry M, Jones H, Zupanec S, Li C, Crabtree VM, Mandrell BN, Schoumacher RA, Vallance K, Sanford S, Srivastava DK. Psychometric and clinical assessment of the 10-item reduced version of the Fatigue Scale-Child instrument. J Pain Symptom Manage 2010; 39:572-8. [PMID: 20303031 PMCID: PMC2941159 DOI: 10.1016/j.jpainsymman.2009.07.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 07/31/2009] [Accepted: 07/31/2009] [Indexed: 10/19/2022]
Abstract
Fatigue is one of the most debilitating conditions associated with cancer and anticancer therapy. The lack of reliable and valid self-report instruments has prevented accurate assessment of fatigue in pediatric oncology patients. The purpose of this study was to identify the most sensitive and specific score, that is, the "cut score," on the Fatigue Scale-Child (FS-C) to identify those children with high cancer-related fatigue in need of clinical intervention. We first used Rasch methods to identify the items on the FS-C that distinguished children with high cancer-related fatigue from other children; our findings indicated that the FS-C needed to be reduced from 14 items to 10 items. We then assessed the 10-item FS-C for its psychometric properties and applied the receiver operating characteristics curve analysis to the FS-C responses from 221 children (aged 7-12 years) receiving anticancer treatment. The cut score identified with 75% sensitivity and 73.5% specificity was 12; 73 (33%) patients scored 12 or higher. Findings from this validated instrument provide a needed guide for clinicians to interpret fatigue scores and provide clinical interventions for this debilitating condition to their pediatric patients with cancer.
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Affiliation(s)
- Pamela S Hinds
- Department of Nursing Research, Children's National Medical Center, George Washington University, Washington, DC 20010, USA.
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Ruiz FE, Clancy JP, Perricone MA, Bebok Z, Hong JS, Cheng SH, Meeker DP, Young KR, Schoumacher RA, Weatherly MR, Wing L, Morris JE, Sindel L, Rosenberg M, van Ginkel FW, McGhee JR, Kelly D, Lyrene RK, Sorscher EJ. A clinical inflammatory syndrome attributable to aerosolized lipid-DNA administration in cystic fibrosis. Hum Gene Ther 2001; 12:751-61. [PMID: 11339892 DOI: 10.1089/104303401750148667] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Immunologic reactivity to lipid-DNA conjugates has traditionally been viewed as less of an issue than with viral vectors. We performed a dose escalation safety trial of aerosolized cystic fibrosis transmembrane conductance regulator (CFTR) cDNA to the lower airways of eight adult cystic fibrosis patients, and monitored expression by RT-PCR. The cDNA was complexed to a cationic lipid amphiphile (GL-67) consisting of a cholesterol anchor linked to a spermine head group. CFTR transgene was detected in three patients at 2-7 days after gene administration. Four of the eight patients developed a pronounced clinical syndrome of fever (maximum of 103.3EF), myalgias, and arthralgia beginning within 6 hr of gene administration. Serum IL-6 but not levels of IL-8, IL-1, TNF-alpha, or IFN-gamma became elevated within 1-3 hr of gene administration. No antibodies to the cationic liposome or plasmid DNA were detected. We found that plasmid DNA by itself elicited minimal proliferation of peripheral blood mononuclear cells taken from study patients, but led to brisk immune cell proliferation when complexed to a cationic lipid. Lipid and DNA were synergistic in causing this response. Cellular proliferation was also seen with eukaryotic DNA, suggesting that at least part of the immunologic response to lipid-DNA conjugates is independent of unmethylated (E. coli-derived) CpG sequences that have previously been associated with innate inflammatory changes in the lung.
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Affiliation(s)
- F E Ruiz
- Gregory Fleming James Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Quasney MW, Orman K, Thompson J, Ring JC, Salim M, Schoumacher RA, Watson D, Novick W, Deitcher SR, Joyner R. Plastic bronchitis occurring late after the Fontan procedure: treatment with aerosolized urokinase. Crit Care Med 2000; 28:2107-11. [PMID: 10890673 DOI: 10.1097/00003246-200006000-00074] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To describe the use of aerosolized urokinase in a patient with plastic bronchitis after a Fontan procedure. DESIGN Case report. SETTING Pediatric intensive care unit in a university-affiliated children's hospital. PATIENTS Report of one patient with acute respiratory failure secondary to plastic bronchitis. INTERVENTIONS Aerosolized urokinase, multiple bronchoscopies, corticosteroids, mucolytics, bronchodilators, and atrial pacing. MEASUREMENTS AND MAIN RESULTS Airway obstruction secondary to recurring casts improved with the treatments. Histologic analysis of the casts demonstrated less fibrin after treatments with aerosolized urokinase. No adverse events were noted. CONCLUSIONS The addition of aerosolized urokinase to this patient's treatment regimen helped to resolve life-threatening airway obstruction secondary to fibrin casts.
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Affiliation(s)
- M W Quasney
- Department of Pediatrics, Crippled Children's Foundation Research Center, Memphis, TN 38103, USA.
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Affiliation(s)
- J D Tutor
- Department of Pediatrics, College of Medicine, University of Tennessee, Memphis, USA.
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Thompson JW, Nguyen CD, Lazar RH, Stocks RM, Schoumacher RA, Hamdan F, Van Nguyen K. Evaluation and management of hemoptysis in infants and children. A report of nine cases. Ann Otol Rhinol Laryngol 1996; 105:516-20. [PMID: 8678426 DOI: 10.1177/000348949610500704] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Hemoptysis is an occasional complication of adult pulmonary disease and is rare in children. The most common causes in adults are infection, bronchiectasis, pulmonary neoplasm, cystic fibrosis, pulmonary infarct, and trauma; in children the most common causes are infection and congenital abnormalities of the cardiopulmonary vasculature. Nine cases of hemoptysis in seven infants and two children will be presented. Two cases were fatal, thus illustrating the importance of rapid and definitive therapy early in the course. One of the fatal cases is the first case report in the otolaryngological literature of fatal hemoptysis in the newborn as a result of vascular anomalies associated with an absent left pulmonary artery. Eight cases of various causes, including small vessel vascular abnormality, trauma, recurrent pulmonary infection, and laryngotracheal papilloma, are discussed. The literature is reviewed, embryology is discussed, and a mechanism of death is theorized for the patient with the congenital vessel anomaly. Management considerations for hemoptysis in infants and children are discussed.
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Affiliation(s)
- J W Thompson
- Department of Pediatrics, University of Tennessee, Memphis 38105, USA
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Abstract
We compared the efficacy of manual and mechanical chest percussion during hospitalization for acute exacerbations of cystic fibrosis by evaluating changes in spirometry values. Fifty-one participants were randomly assigned to receive manual or mechanical chest percussion three times a day. Twenty-two participated during one subsequent admission and were assigned to the opposite form of chest percussion. The two groups were equal in severity of illness (mean National Institutes of Health score (+/- SEM): manual = 66.7 +/- 2.2; mechanical = 35.8 +/- 2.2; p = not significant). Mean improvement in forced expiratory volume at 1 second, forced vital capacity, and forced expiratory flow between 25% and 75% of forced vital capacity (+/- SEM) for manual percussion was 32.6% +/- 7%, 27.2% +/- 5%, and 38.1% +/- 10%, and for mechanical percussion was 28.5% +/- 4%, 28.7% +/- 4%, and 25.1% +/- 8%, respectively; p = not significant. Our participants did not prefer mechanical chest percussion. Although equal efficacy of outpatient therapy remains to be proved, this study suggests that patients can be encouraged to use the form of chest percussion that they prefer.
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Affiliation(s)
- M L Bauer
- Pediatric Pulmonary Section, University of Alabama at Birmingham
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Phillips OP, Elias S, Woods D, Hanissian AS, Schoumacher RA, Bishop C. Cystic fibrosis mutations in white and black Americans: an approach to identification of unknown mutations with implications for cystic fibrosis screening. Am J Obstet Gynecol 1993; 168:1076-82. [PMID: 8475954 DOI: 10.1016/0002-9378(93)90350-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE We sought to define the frequency of common cystic fibrosis mutations in white and black American probands from our geographic region. STUDY DESIGN Mutation analysis was performed for delta F508, G551D, G542X, R553X, S549N, an d N1303K. For probands with undetermined mutations single-stranded conformational polymorphism analysis was performed. RESULTS Among 40 white subjects with cystic fibrosis 26 (65%) were homozygous for delta F508, 10 (25%) were heterozygous for delta F508 and another unknown mutation, and two were homozygous for unknown mutations. Among 10 black probands one was homozygous for delta F508, seven (70%) were heterozygous for delta F508 and another unknown mutation, and one was homozygous for unknown mutations. Single-stranded conformational polymorphism analysis for selected exons was performed for 11 probands with unknown mutations. One mutation was detected in a white proband. Sequencing of this exon showed the mutation to be Q493X. CONCLUSIONS Thirty percent of white subjects and 80% of black subjects carried unknown mutations. In one family single-stranded conformational polymorphism was informative in identifying an undetermined cystic fibrosis mutation.
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Affiliation(s)
- O P Phillips
- Department of Obstetrics and Gynecology, University of Tennessee, Memphis
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12
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Abstract
Retrovirus-mediated transfection of cDNA for the cystic fibrosis (CF) gene into the CF pancreatic cell line, CFPAC-1, confers adenosine 3',5'-cyclic monophosphate (cAMP)-dependent regulation of Cl conductance. We used patch-clamp techniques to identify the single-channel basis of this conductance pathway and to study its properties. Forskolin or cAMP activated Cl channels with a conductance of 9 +/- 1 pS in 26 of 62 cell-attached patches of cystic fibrosis transmembrane conductance regulator (CFTR)-transfected CFPAC-1 cells. The current-voltage (I-V) relation showed slight outward rectification (chord conductance of 10 +/- 2 pS at +80 mV vs. 7 +/- 1 pS at -80mV) with high Cl concentrations (170 mM) in the pipette solution. Channel kinetics were voltage sensitive, with longer openings at positive clamp voltages. Channel properties were unaffected by the substitution of N-methyl-D-glucamine for pipette Na or by the addition of disulfonic stilbenes (100 microM DNDS or DIDS) to the pipette. The channels usually inactivated within seconds of patch excision, but in three of nine patches, activity could be maintained by addition of the catalytic subunit of protein kinase A and ATP. With equal Cl concentrations on both membrane surfaces, the single-channel I-V relation was linear, suggesting that the outward rectification of the cell-attached channel is due to a pipette-to-cell Cl gradient. Anion substitution on the extracellular side of the membrane indicates a halide permselectivity of Br approximately Cl greater than I.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- W H Cliff
- Department of Physiology, University of Alabama, Birmingham 35294
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Miszczuk-Jamska B, Merten M, Guy-Crotte O, Amouric M, Clemente F, Schoumacher RA, Figarella C. Characterization of trypsinogens 1 and 2 in two human pancreatic adenocarcinoma cell lines; CFPAC-1 and CAPAN-1. FEBS Lett 1991; 294:175-8. [PMID: 1756857 DOI: 10.1016/0014-5793(91)80662-m] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Proteins with trypsin-like immunoreactivity (first detected by a specific immunoenzymatic assay) were isolated from CAPAN-1 and CFPAC-1 cell culture-conditioned media by chromatography on an immunoadsorbent prepared with a polyclonal antibody directed against trypsin 1. The adsorbed proteins were devoid of free trypsin activity but trypsin activity was present after enterokinase activation demonstrating that the immunoreactive trypsin present in cell supernatants corresponds to trypsinogens. When characterised by Western blotting using a monoclonal antibody directed against human trypsin 1 two protein bands corresponding to trypsinogen 1 (23 kDa) and trypsinogen 2 (25 kDa) gave a positive reaction. These results demonstrate the presence of trypsinogens 1 and 2 in CAPAN-1 and CFPAC-1 cells and in their culture-conditioned media.
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Schoumacher RA, Ram J, Iannuzzi MC, Bradbury NA, Wallace RW, Hon CT, Kelly DR, Schmid SM, Gelder FB, Rado TA. A cystic fibrosis pancreatic adenocarcinoma cell line. Proc Natl Acad Sci U S A 1990; 87:4012-6. [PMID: 1692630 PMCID: PMC54034 DOI: 10.1073/pnas.87.10.4012] [Citation(s) in RCA: 186] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We established a pancreatic adenocarcinoma cell line (CFPAC-1) from a patient with cystic fibrosis (CF) and assessed some of its properties. The cells show epithelial morphology and express cytokeratin and oncofetal antigens characteristic of pancreatic duct cells. Basal and stimulated levels of cAMP and cAMP-dependent protein kinase and the biophysical properties of single Cl- channels in CFPAC-1 are similar to those of airway and sweat gland primary cultures and Cl(-)-secreting epithelial cell lines. Anion transport and single Cl- channel activity was stimulated by Ca2+ ionophores but not by forskolin, cAMP analogs, or phosphodiesterase inhibitors. The cells express the CF gene and manifest the most common CF mutation, deletion of three nucleotides resulting in a phenylalanine-508 deletion. These properties have been stable through greater than 80 passages (24 months), suggesting that CFPAC-1 can serve as a continuous cell line that displays the CF defect.
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Affiliation(s)
- R A Schoumacher
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham 35294
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Halm DR, Rechkemmer GR, Schoumacher RA, Frizzell RA. Apical membrane chloride channels in a colonic cell line activated by secretory agonists. Am J Physiol 1988; 254:C505-11. [PMID: 2451430 DOI: 10.1152/ajpcell.1988.254.4.c505] [Citation(s) in RCA: 133] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We characterized the anion channel responsible for the increase in apical membrane Cl secretion using a model salt-secreting epithelium, the T84 colonic cell line. The adenosine 3',5'-cyclic monophosphate (cAMP)-mediated secretagogues, prostaglandin E2, forskolin, and 8-bromo-cAMP, evoked activity of an outwardly rectifying Cl channel in previously quiet cell-attached membrane patches. The channel remained active in excised, inside-out membranes, where its single-channel conductance was 40-45 pS at 0 mV with 160 mM NaCl in pipette and bath. Selectivities were PCl/PNa = 50 and for halides I(1.8)/Br(1.4)/Cl(1.0)/F(0.4). This halide sequence illustrates that the ability of various anions to undergo transepithelial secretion is determined by the selectivity of the basolateral membrane Cl entry step rather than by the apical Cl channel. Open-channel probability increased with depolarization, an effect that would adjust the rate of Cl exit across secretory cell apical membranes with agonist-induced changes in apical membrane potential. Comparison with the properties of Cl channels detected in other cell types suggests that this cAMP-stimulated Cl channel is uniquely present in the apical membranes of salt-secreting epithelial cells.
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Affiliation(s)
- D R Halm
- Department of Physiology, University of Alabama at Birmingham, University Station 35294
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Halm DR, Rechkemmer G, Schoumacher RA, Frizzell RA. Biophysical properties of a chloride channel in the apical membrane of a secretory epithelial cell. Comp Biochem Physiol A Comp Physiol 1988; 90:597-601. [PMID: 2460284 DOI: 10.1016/0300-9629(88)90673-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. Patch clamp studies on colonic tumor cell line T84 show the presence of chloride channels. 2. The channels are activated by forskolin, PGE2, or 8-Br-cAMP. 3. Single channel conductance was ca 40 pS at the reversal potential, increasing to 70 pS at +80 mV and decreasing to 25 pS at -80 mV. 4. Relative permeabilities were I greater than Br greater than Cl greater than F.
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Affiliation(s)
- D R Halm
- Department of Physiology and Biophysics, University of Alabama, Birmingham 35294
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Schoumacher RA, Shoemaker RL, Halm DR, Tallant EA, Wallace RW, Frizzell RA. Phosphorylation fails to activate chloride channels from cystic fibrosis airway cells. Nature 1987; 330:752-4. [PMID: 2447502 DOI: 10.1038/330752a0] [Citation(s) in RCA: 280] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Chloride impermeability of epithelial cells can account for many of the experimental and clinical manifestations of cystic fibrosis (CF). Activation of apical-membrane Cl- channels by cyclic AMP-mediated stimuli is defective in CF airway epithelial cells, despite normal agonist-induced increases in cellular cAMP levels. This defect in Cl- channel regulation has been localized to the apical membrane by exposing the cytoplasmic surface of excised membrane patches to the catalytic subunit (C subunit) of cAMP-dependent protein kinase and ATP. In membranes from normal cells, C-subunit activated Cl- channels with properties identical to those stimulated by cAMP-dependent agonists during cell-attached recording. Activation by the C subunit was not observed in CF membranes, but the presence of Cl- channels was verified by voltage-induced activation. The failure of the C subunit to activate the Cl- channels of CF membranes indicates that the block in their cAMP-mediated activation lies distal to induction of cAMP-dependent protein kinase activity and focuses our attention on the Cl- channel and its membrane-associated regulatory proteins as the probable site of the CF defect.
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Affiliation(s)
- R A Schoumacher
- Department of Pediatrics, University of Alabama, Birmingham 35294
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Schoumacher RA, Tiller RE, Berkow RL. Invasive pulmonary aspergillosis in an infant: an unusual presentation of chronic granulomatous disease. Pediatr Infect Dis J 1987; 6:215-7. [PMID: 3562145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
Within 3 years we saw 12 patients diagnosed initially as having poorly differentiated or undifferentiated carcinomas who, we believe, actually had extragonadal germinal cancers. Serum levels of the beta subunit of human chorionic gonadotropin (beta-HCG) or alpha-fetoprotein were useful in suggesting and supporting the diagnosis: Levels of one or the other were elevated in six of 10 patients in whom they were measured but levels of both, in only one patient. Staining of histologic specimens for beta-HCG or alpha-fetoprotein showed intracellular localization of one of these markers in the cancer cells of all four patients studied. All patients responded to therapy (11 treated with chemotherapy with or without radiotherapy, one with excision and radiotherapy only), with complete remissions in seven of 12. Two of the patients who had a complete remission have experienced relapse, and five have continued in disease-free remission from more than 8 to more than 56 months. Histologically atypical extragonadal germ cell neoplasms may be commoner than previously supposed. Physicians should consider this treatable and potentially curable cancer in selected patients having poorly differentiated or undifferentiated carcinomas.
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