Poison-related visits in a pediatric emergency department: A retrospective analysis of patients who bypass poison control centers.

INTRODUCTION: Poison control centers (PCC) are an effective means to prevent unnecessary emergency department (ED) visits associated with poisoning exposures. However, not all patients with poison exposures utilize the PCC. The purpose of this study was to identify unintentional pediatric poisoning exposures presenting to a large US children's hospital that could have been managed onsite (i.e., at home) if consultation with a PCC had occurred prior to the ED visit. METHODS: Using ED encounters from a tertiary children's hospital, unintentional pharmaceutical, chemical, or fume exposures occurring between October 1, 2014 and September 30, 2015 were identified from ICD-9-CM billing codes. Two specialists in poison information reviewed the medical records of the identified patients who had no contact with the PCC and determined whether these encounters were preventable through PCC triage. Descriptive statistics examined the differences between the encounters. Data were analyzed in R v3.2.4 (Vienna, Austria) and SAS v9.4 (SAS Institute, Cary, NC). RESULTS: In the total study population (n = 231), 98 (42.4%) were PCC triaged and 133 (57.6%) were caregiver self-referred to the ED. For those who self-referred, 62 (46.6%) patients would have been recommended to be managed onsite instead of presenting at the ED for medical care. Analgesics and household cleaning products were the most common pharmaceutical and chemical exposures, respectively. CONCLUSIONS: Nearly half of ED visits for pediatric patients with unintentional poisoning exposures could have been avoided by contacting a PCC. Educational and self-efficacy-based interventions are needed to expand the public's use of PCC services.

Assessment of the efficiency of language interpreter services in a busy surgical and procedural practice.

BACKGROUND: Surgical and procedural patient care settings require efficient patient flow. The primary goal of this study was to assess use and efficiency of language services for our limited English proficiency (LEP) patients undergoing surgical and outpatient procedures. METHODS: Patient language services needs were recorded from our operating room and procedural locations over a two and a half month period in 2016. Time from in-person interpreter request to arrival was recorded. Frequency of language service modality used and reason for telephone and professional video remote interpreting (VRI) rather than in person professional services was queried. RESULTS: Mean time from in-person interpreter request until arrival was 19 min. Variation was high. No cases were cancelled due to lack of available interpretive services and no LEP patient underwent a procedure without requested interpretative service assistance. CONCLUSIONS: Time for in person professional interpreter assistance was short but highly variable. Access to telephone interpretive services and VRI services ensured assistance when in person interpreters were immediately unavailable. With the numbers of LEP patients increasing over time along with any new mandates for providing language assistance, the stress on hospital patient service units and the financial implications for many health care facilities will likely continue as challenges.

Phylogeny, Morphology, Distribution, and Pathogenicity of Botryosphaeriaceae and Diaporthaceae from English Walnut in California.

Species of family Botryosphaeriaceae and genus Diaporthe (anamorph: genus Phomopsis, family Diaporthaceae) were reported and caused diseases on various fruit and nut trees in California. In the last several years, diseases on English walnut (Juglans regia) caused by species of Botryosphaeriaceae and Diaporthe were observed frequently in California. Disease symptoms include stem canker; shoot canker and blight; twig, leaf, and fruit blight; and necrotic leaf lesions. Isolates of the pathogen were collected from English walnut in 13 counties in California. The aims of this study were to identify these isolates and to test their pathogenicity to English walnut cultivars. In total, 159 California isolates were identified based on comparisons of DNA sequence data of the internal transcribed spacer, translation elongation factor 1-α, and ß-tubulin gene regions, and combined with the morphological features of the cultures and conidia. Research results revealed that isolates represent 10 species of Botryosphaeriaceae and two species of Diaporthe. These species include Botryosphaeria dothidea, Diplodia mutila, D. seriata, Dothiorella iberica, Lasiodiplodia citricola, Neofusicoccum mediterraneum, N. nonquaesitum, N. parvum, N. vitifusiforme, Neoscytalidium dimidiatum, Diaporthe neotheicola, and D. rhusicola. Pathogenicity on three English walnut cultivars ('Chandler', 'Tulare', and 'Vina') using a mycelium plug inoculation method revealed that all these species are pathogenic to all the tested cultivars, with L. citricola and N. parvum being the most pathogenic species, followed by N. mediterraneum, N. dimidiatum, and B. dothidea. Chandler was more tolerant to infection than Tulare and Vina. Results in this study determined that multiple numbers of the Botryosphaeriaceae fungi and two Diaporthe spp. cause cankers and blights of English walnut and vary in their virulence from highly to slightly virulent, respectively.

DNA methylation of SPARC and chronic low back pain.

BACKGROUND: The extracellular matrix protein SPARC (Secreted Protein, Acidic, Rich in Cysteine) has been linked to degeneration of the intervertebral discs and chronic low back pain (LBP). In humans, SPARC protein expression is decreased as a function of age and disc degeneration. In mice, inactivation of the SPARC gene results in the development of accelerated age-dependent disc degeneration concurrent with age-dependent behavioral signs of chronic LBP.DNA methylation is the covalent modification of DNA by addition of methyl moieties to cytosines in DNA. DNA methylation plays an important role in programming of gene expression, including in the dynamic regulation of changes in gene expression in response to aging and environmental signals. We tested the hypothesis that DNA methylation down-regulates SPARC expression in chronic LBP in pre-clinical models and in patients with chronic LBP. RESULTS: Our data shows that aging mice develop anatomical and behavioral signs of disc degeneration and back pain, decreased SPARC expression and increased methylation of the SPARC promoter. In parallel, we show that human subjects with back pain exhibit signs of disc degeneration and increased methylation of the SPARC promoter. Methylation of either the human or mouse SPARC promoter silences its activity in transient transfection assays. CONCLUSIONS: This study provides the first evidence that DNA methylation of a single gene plays a role in chronic pain in humans and animal models. This has important implications for understanding the mechanisms involved in chronic pain and for pain therapy.

Formulation of a killed whole cell pneumococcus vaccine - effect of aluminum adjuvants on the antibody and IL-17 response.

BACKGROUND: Streptococcus pneumoniae causes widespread morbidity and mortality. Current vaccines contain free polysaccharides or protein-polysaccharide conjugates, and do not induce protection against serotypes that are not included in the vaccines. An affordable and broadly protective vaccine is very desirable. The goal of this study was to determine the optimal formulation of a killed whole cell pneumococcal vaccine with aluminum-containing adjuvants for intramuscular injection. METHODS: Four aluminium-containing adjuvants were prepared with different levels of surface phosphate groups resulting in different adsorptive capacities and affinities for the vaccine antigens. Mice were immunized three times and the antigen-specific antibody titers and IL-17 responses in blood were analyzed. RESULTS: Although all adjuvants induced significantly higher antibody titers than antigen without adjuvant, the vaccine containing aluminum phosphate adjuvant (AP) produced the highest antibody response when low doses of antigen were used. Aluminum hydroxide adjuvant (AH) induced an equal or better antibody response at high doses compared with AP. Vaccines formulated with AH, but not with AP, induced an IL-17 response. The vaccine formulated with AH was stable and retained full immunogenicity when stored at 4°C for 4 months. CONCLUSIONS: Antibodies are important for protection against systemic streptococcal disease and IL-17 is critical in the prevention of nasopharyngeal colonization by S. pneumoniae in the mouse model. The formulation of the whole killed bacterial cells with AH resulted in a stable vaccine that induced both antibodies and an IL-17 response. These experiments underscore the importance of formulation studies with aluminium containing adjuvants for the development of stable and effective vaccines.

Effect of systemic steroids on humming nasal nitric oxide in chronic rhinosinusitis with nasal polyposis.

BACKGROUND: Increased nasal nitric oxide (NO) is a marker for paranasal sinus ostial patency. However, there are no data evaluating the effect of systemic steroids on humming nasal NO in chronic rhinosinusitis with nasal polyposis (CRSNP). OBJECTIVES: To assess whether 2 weeks of oral steroids in CRSNP increases humming nasal NO, whether humming is a more sensitive indicator of this increase than other methods of measuring NO, and whether it correlates with improvements in clinical parameters for sinonasal disease. METHODS: Adults with CRSNP (grade 2 and above) were treated with oral prednisolone, 25 mg/d for 2 weeks. Nasal NO was measured by aspiration, exhalation at 0.2 L·s⁻¹, and humming methods. Peak nasal inspiratory flow, Sinonasal Outcomes Test 20 score, symptoms, olfaction, and polyp grade were also measured before and after treatment. RESULTS: Twelve patients (mean age, 49 years) completed the treatment. The differences in nasal NO before and after steroid treatment were significantly less pronounced as measured by geometric mean-fold ratio with aspiration (1.5; 95% confidence interval [CI], 1.1 to 1.9; P = .009) and exhalation (2.1; 95% CI, 1.2 to 3.9; P = .02) compared with the humming technique (4.9; 95% CI, 2.2 to 10.7; P = .001). The standardized response means for the methods of NO estimation were 0.97 for aspiration, 1.05 for exhalation, and 1.61 for humming. CONCLUSIONS: This study demonstrates that humming nasal NO increases after 2 weeks of oral steroid therapy for CRSNP. Humming NO is more sensitive than aspiration and exhalation and is associated with improvements in symptoms, polyp size, and quality of life. Humming NO may fill the niche for a noninvasive marker of sinus ostial patency.

Breath alcohol analyzer mistakes methanol poisoning for alcohol intoxication.

Breath alcohol analyzers are used to detect ethanol in motorists and others suspected of public intoxication. One concern is their ability to detect interfering substances that may falsely increase the ethanol reading. A 47-year-old-man was found in a public park, acting intoxicated. A breath analyzer test (Intoxilyzer 5000EN) measured 0.288 g/210 L breath ethanol, without an interferent noted. In the emergency department, the patient admitted to drinking HEET Gas-Line antifreeze, which contains 99% methanol. Two to three hours after ingestion, serum and urine toxicology screen results were negative for ethanol and multiple other substances. His serum methanol concentration was 589 mg/dL, serum osmolality 503 mOsm/kg, osmolar gap 193 mOsm/kg, and anion gap 17 mmol/L. The patient was treated with intravenous ethanol, fomepizole, and hemodialysis without complication. This is a unique clinical case of a breath alcohol analyzer reporting methanol as ethanol. Intoxilyzer devices have been shown to indicate some substances (acetone) as interferents in humans but not methanol. Increased serum concentrations of methanol can be reported as ethanol by a commonly used breath alcohol analyzer, which can result in a delayed diagnosis or misdiagnosis and subsequent methanol toxicity if antidotal treatment is not administered in a timely manner.

Partial characterization of feline myeloperoxidase and investigation of its potential role as an autoantigen in hyperthyroid cats.

OBJECTIVE: To partially characterize the cDNA, amino acid sequence, and tertiary structure of feline myeloperoxidase, describe its cellular location in mature granulocytes, and determine whether hyperthyroid cats have anti-myeloperoxidase antibody. SAMPLE POPULATION: Bone marrow RNA and whole blood from cats of various sources and feline serum samples submitted for measurement of total thyroxine concentration from September 2006 to July 2007. PROCEDURES: Feline myeloperoxidase cDNA was amplified from bone marrow RNA; presumptive splice sites were determined by comparison with human sequences. Intracellular localization of myeloperoxidase in granulocytes was determined by use of immunofluorescence and electron microscopy, and molecular weight and partial tertiary structure were determined by use of immunoblotting of granulocyte lysates. Anti-human myeloperoxidase (hMPO) antibody was detected via ELISA. RESULTS: A 2,493-bp sequence encompassing the 2,160-bp cDNA with presumably the same number and size of exons as hMPO was generated. Translation predicted 85% homology with hMPO. Feline myeloperoxidase was localized to neutrophil primary granules, and immunoblotting revealed heavy and light bands with molecular weights similar to those of hMPO. The prevalence of anti-hMPO antibody did not differ between nonhyperthyroid and hyperthyroid cats or among hyperthyroid cats subclassified by treatment modality. CONCLUSIONS AND CLINICAL RELEVANCE: Moderate homology existed between feline myeloperoxidase and hMPO cDNA and protein. Although findings suggested a similar tertiary structure and function for the 2 proteins, they also suggested that inability to detect a high prevalence of anti-hMPO antibody in hyperthyroid cats may be attributable to antigenic differences between the human and feline proteins rather than a lack of autoantibody.

Examining the artist-patient relationship in palliative care. A thematic analysis of artist reflections on encounters with palliative patients.

BACKGROUND: Although therapeutic arts are used in the palliative care setting, little has been described about what happens during the artist-patient encounter and how these interactions can complement and integrate into the interdisciplinary model of palliative care. The objective of this study is to describe the artist-patient encounter and how artists can function in the palliative interdisciplinary model of care. METHODS: Authors reviewed 229 reports written by artists about encounters with palliative patients, and performed thematic analysis on 95. RESULTS: Artists describe physical, emotional and spiritual responses by patients including relaxation, invigoration and accessing spirituality, some of which were unique to the artist-patient interaction. Artists also described personal reactions including themes of professional fulfillment, kinship and empathy with patient suffering. Themes surrounding the artist-patient bond and trust also emerged. CONCLUSIONS: The artist-patient encounter has an effect on both patients and artists, and can create a therapeutic relationship between them. Artists provide unique perspectives and contribute to care paradigms when integrated with  the palliative team.

Interleukin-8 as a therapeutic target for chronic low back pain: Upregulation in human cerebrospinal fluid and pre-clinical validation with chronic reparixin in the SPARC-null mouse model.

BACKGROUND: Low back pain (LBP) is the leading global cause of disability and is associated with intervertebral disc degeneration (DD) in some individuals. However, many adults have DD without LBP. Understanding why DD is painful in some and not others may unmask novel therapies for chronic LBP. The objectives of this study were to a) identify factors in human cerebrospinal fluid (CSF) associated with chronic LBP and b) examine their therapeutic utility in a proof-of-concept pre-clinical study. METHODS: Pain-free human subjects without DD, pain-free human subjects with DD, and patients with chronic LBP linked to DD were recruited and lumbar MRIs, pain and disability levels were obtained. CSF was collected and analyzed by multiplex cytokine assay. Interleukin-8 (IL-8) expression was confirmed by ELISA in CSF and in intervertebral discs. The SPARC-null mouse model of progressive, age-dependent DD and chronic LBP was used for pre-clinical validation. Male SPARC-null and control mice received systemic Reparixin, a CXCR1/2 (receptors for IL-8 and murine analogues) inhibitor, for 8 weeks. Behavioral signs of axial discomfort and radiating pain were assessed. Following completion of the study, discs were excised and cultured, and conditioned media was evaluated with a protein array. FINDINGS: IL-8 was elevated in CSF of chronic LBP patients with DD compared to pain-free subjects with or without DD. Chronic inhibition with reparixin alleviated low back pain behaviors and attenuated disc inflammation in SPARC-null mice. INTERPRETATION: These studies suggest that the IL-8 signaling pathway is a viable therapy for chronic LBP. FUND: Supported by NIH, MMF, CIHR and FRQS.

Syntactic complexity during conversation of boys with fragile X syndrome and Down syndrome.

PURPOSE: This study compared the syntax of boys who have fragile X syndrome (FXS) with and without autism spectrum disorder (ASD) with that of (a) boys who have Down syndrome (DS) and (b) typically developing (TD) boys. METHOD: Thirty-five boys with FXS only, 36 boys with FXS with ASD, 31 boys with DS, and 46 TD boys participated. Conversational language samples were evaluated for utterance length and syntactic complexity (i.e., Index of Productive Syntax; H. S. Scarborough, 1990). RESULTS: After controlling for nonverbal mental age and maternal education levels, the 2 FXS groups did not differ in utterance length or syntactic complexity. The FXS groups and the DS group produced shorter, less complex utterances overall and less complex noun phrases, verb phrases, and sentence structures than did the TD boys. The FXS with ASD group and the DS group, but not the FXS-only group, produced less complex questions/negations than did the TD group. Compared with the DS group, both FXS groups produced longer, more complex utterances overall, but on the specific complexity measures, they scored higher only on questions/negations. CONCLUSION: Boys with FXS and DS have distinctive language profiles. Although both groups demonstrated syntactic delays, boys with DS showed greater delays.

Characterizing the Use of Telepsychiatry for Patients with Opioid Use Disorder and Cooccurring Mental Health Disorders in Ontario, Canada.

Rural patients with opioid use disorder (OUD) face a variety of barriers when accessing opioid agonist therapy (OAT) and psychiatric services, due to the limited supply of physicians and the vast geographic area. The telemedicine allows for contact between patients and their physician-regardless of physical distance. Objective. We characterize the usage of telemedicine to deliver psychiatric services to patients with OUD in Ontario, as well as traits of treatment-seeking patients with opioid dependence and concurrent psychiatric disorders. Methodology. A retrospective cohort study was conducted using an administrative database for patients who received psychiatric services via telemedicine between 2008 and 2014 and who also had OUD. Results. We identified 9,077 patients with concurrent opioid use and other mental health disorders who had received psychiatric services via telemedicine from 2008 to 2014; 7,109 (78.3%) patients lived in Southern Ontario and 1,968 (21.7%) in Northern Ontario. Telemedicine was used more frequently to provide mental health services to patients residing in Northern Ontario than Southern Ontario. Conclusion. Telemedicine is increasingly being utilized throughout Ontario for delivering mental health treatment. There is an opportunity to increase access to psychiatric services for patients with opioid dependence and concurrent psychiatric disorders through the use of the telemedicine.

Comparison of finger tracking versus simple movement training via telerehabilitation to alter hand function and cortical reorganization after stroke.

OBJECTIVE: To compare 2 telerehabilitation training strategies, repetitive tracking movements versus repetitive simple movements, to promote brain reorganization and recovery of hand function. METHODS: Twenty subjects with chronic stroke and 10 degrees of voluntary finger extension were randomly assigned to receive 1800 telerehabilitation trials over 2 weeks of either computerized tracking training (track group) with the affected finger and wrist involving temporospatial processing to achieve accuracy or movement training (move group) with no attention to accuracy. Following movement training, the move group crossed over to receive an additional 2 weeks of tracking training. Behavioral changes were measured with the Box and Block test, Jebsen Taylor test, and finger range of motion, along with a finger-tracking activation paradigm during fMRI. RESULTS: The track group showed significant improvement in all 4 behavioral tests; the move group improved in the Box and Block and Jebsen Taylor tests. The improvement for the track group in the Box and Block and Jebsen Taylor tests did not surpass that for the move group. A consistent group pattern of brain reorganization was not evident. The move group, after crossing over, did not show further significant improvements. CONCLUSION: Telerehabilitation may be effective in improving performance in subjects with chronic stroke. Tracking training with reinforcement to enhance learning, however, did not produce a clear advantage over the same amount of practice of random movements. Two weeks of training may be insufficient to demonstrate a behavioral advantage and associated brain reorganization.

Expressive language during conversational speech in boys with fragile X syndrome.

We compared the expressive syntax and vocabulary skills of 35 boys with fragile X syndrome and 27 younger typically developing boys who were at similar nonverbal mental levels. During a conversational speech sample, the boys with fragile X syndrome used shorter, less complex utterances and produced fewer different words than did the typically developing boys after controlling for their nonverbal MA, speech intelligibility, and mother's education. The boys with fragile X used less complex noun phrases, verb phrases, and sentence structure, but did not use fewer questions and negations. These findings suggest that the language difficulties in boys with fragile X reflect an overall expressive language delay and not a specific syntactic or vocabulary delay.

Receptive vocabulary, expressive vocabulary, and speech production of boys with fragile X syndrome in comparison to boys with down syndrome.

Boys with fragile X syndrome with (n = 49) and without (n = 33) characteristics of autism spectrum disorder, boys with Down syndrome (39), and typically developing boys (n = 41) were compared on standardized measures of receptive vocabulary, expressive vocabulary, and speech administered annually over 4 years. Three major findings emerged. Boys with fragile X without autism spectrum disorder did not differ from the younger typically developing boys in receptive and expressive vocabulary and speech production when compared at similar levels of nonverbal cognitive skills. Boys with fragile X without autism spectrum disorder and typically developing boys had higher receptive vocabulary and speech production than did boys with Down syndrome. There were mixed patterns of results for the boys with fragile X and characteristics of autism spectrum disorder.

Image-guided stereotactic radiosurgery using a specially designed high-dose-rate linac.

Stereotactic radiosurgery and image-guided radiotherapy (IGRT) place enhanced demands on treatment delivery machines. In this study, we describe a high-dose-rate output accelerator as a part of our stereotactic IGRT delivery system. The linac is a Siemens Oncor without a flattening filter, and enables dose rates to reach 1000 monitor units (MUs) per minute. Even at this high-dose-rate, the linac dosimetry system remains robust; constancy, linearity, and beam energy remain within 1% for 3 to 1000 MU. Dose profiles for larger field sizes are not flat, but they are radially symmetric and, as such, able to be modeled by a treatment planning system. Target localization is performed via optical guidance utilizing a 3-dimensional (3D) ultrasound probe coupled to an array of 4 infrared light-emitting diodes. These diodes are identified by a fixed infrared camera system that determines diode position and, by extension, all objects imaged in the room coordinate system. This system provides sub-millimeter localization accuracy for cranial applications and better than 1.5 mm for extracranial applications. Because stereotactic IGRT can require significantly longer times for treatment delivery, the advantages of the high-dose-rate design and its direct impact on IGRT are discussed.

Distinguishing potential bacteria-tumor associations from contamination in a secondary data analysis of public cancer genome sequence data.

BACKGROUND: A variety of bacteria are known to influence carcinogenesis. Therefore, we sought to investigate if publicly available whole genome and whole transcriptome sequencing data generated by large public cancer genome efforts, like The Cancer Genome Atlas (TCGA), could be used to identify bacteria associated with cancer. The Burrows-Wheeler aligner (BWA) was used to align a subset of Illumina paired-end sequencing data from TCGA to the human reference genome and all complete bacterial genomes in the RefSeq database in an effort to identify bacterial read pairs from the microbiome. RESULTS: Through careful consideration of all of the bacterial taxa present in the cancer types investigated, their relative abundance, and batch effects, we were able to identify some read pairs from certain taxa as likely resulting from contamination. In particular, the presence of Mycobacterium tuberculosis complex in the ovarian serous cystadenocarcinoma (OV) and glioblastoma multiforme (GBM) samples was correlated with the sequencing center of the samples. Additionally, there was a correlation between the presence of Ralstonia spp. and two specific plates of acute myeloid leukemia (AML) samples. At the end, associations remained between Pseudomonas-like and Acinetobacter-like read pairs in AML, and Pseudomonas-like read pairs in stomach adenocarcinoma (STAD) that could not be explained through batch effects or systematic contamination as seen in other samples. CONCLUSIONS: This approach suggests that it is possible to identify bacteria that may be present in human tumor samples from public genome sequencing data that can be examined further experimentally. More weight should be given to this approach in the future when bacterial associations with diseases are suspected.

Evidence for a Role of Nerve Injury in Painful Intervertebral Disc Degeneration: A Cross-Sectional Proteomic Analysis of Human Cerebrospinal Fluid.

Intervertebral disc degeneration (DD) is a cause of low back pain (LBP) in some individuals. However, although >30% of adults have DD, LBP only develops in a subset of individuals. To gain insight into the mechanisms underlying nonpainful versus painful DD, human cerebrospinal fluid (CSF) was examined using differential expression shotgun proteomic techniques comparing healthy control participants, subjects with nonpainful DD, and patients with painful DD scheduled for spinal fusion surgery. Eighty-eight proteins were detected, 27 of which were differentially expressed. Proteins associated with DD tended to be related to inflammation (eg, cystatin C) regardless of pain status. In contrast, most differentially expressed proteins in DD-associated chronic LBP patients were linked to nerve injury (eg, hemopexin). Cystatin C and hemopexin were selected for further examination using enzyme-linked immunosorbent assay in a larger cohort. While cystatin C correlated with DD severity but not pain or disability, hemopexin correlated with pain intensity, physical disability, and DD severity. This study shows that CSF can be used to study mechanisms underlying painful DD in humans, and suggests that while painful DD is associated with nerve injury, inflammation itself is not sufficient to develop LBP. PERSPECTIVE: CSF was examined for differential protein expression in healthy control participants, pain-free adults with asymptomatic intervertebral DD, and LBP patients with painful intervertebral DD. While DD was related to inflammation regardless of pain status, painful degeneration was associated with markers linked to nerve injury.

Multiple isoforms of the KC1 cotransporter are expressed in sickle and normal erythroid cells.

OBJECTIVE: The KCl cotransporter (KCC) plays an important role in cellular cation and volume regulation and contributes to the process of volume reduction that accompanies reticulocyte maturation. In human red cells containing sickle hemoglobin, KCl cotransporter activity is high compared to normal cells, and contributes to the deleterious dehydration of sickle reticulocytes. To date, genes for four KCC isoforms have been identified. As a step toward determining which isoform(s) is responsible for the Cl-dependent K fluxes in reticulocytes, human erythroid cells were examined for the presence of various KCC isoform transcripts. METHODS: In vitro differentiated erythroid precursors, and reticulocytes isolated from normal individuals and sickle patients, were examined by reverse-transcriptase PCR for the expression of KCC isoforms. Transient transfection experiments were subsequently performed to characterize a novel KCC1 promoter. RESULTS: Expression of multiple isoforms was detected, with transcripts for KCC1, 3, and 4 detected in all samples of erythroid cells. Two N-terminal splicing variants were detected for both KCC1 and 3. Sickle hemoglobin containing reticulocytes demonstrated KCC isoform expression patterns similar to wild-type cells, except for a consistent difference in the relative abundance of one KCC1 splice variant. This N-terminal variant initiates from a newly described promoter in the KCC1 gene. CONCLUSION: Three KCC genes are expressed in human red cells. Splicing variants arising from the KCC1 and 3 genes are also evident. Structure/function studies of mouse KCC1 suggest that these natural variants could profoundly affect overall cotransporter activity in the red cell.