Development of a scale to evaluate midwives' beliefs about assessing alcohol use during pregnancy.

BACKGROUND: Prenatal alcohol exposure is an important modifiable cause of adverse fetal outcomes during and following pregnancy. Midwives are key providers of antenatal care, and it is important to understand the factors which influence their ability to provide appropriate advice and support to women about alcohol use in pregnancy. The main aim of this study was to develop a psychometrically valid scale to evaluate midwives' beliefs about assessing alcohol use during pregnancy. METHOD: A self-administered questionnaire was developed to evaluate midwives' beliefs about assessing alcohol use during pregnancy, including beliefs about positive and negative consequences of asking about alcohol use, and beliefs about capacity to assess alcohol use. The questionnaire was sent to 245 midwives working for a state-wide country health service in Western Australia. Exploratory factor analysis was used to identify the latent constructs assessed by the 36 belief items and provide initial construct validation of the Asking About Alcohol (AAA) Scale. RESULTS: Of the 166 (67.8 %) midwives who responded to the survey, 160 (96.4 %) completed one or more of the belief items and were included in this analysis. Factor analysis identified six subscales which assessed beliefs about discomfort, capacity, effectiveness, role, trust and knowledge. Midwives held the most positive beliefs about their capacity to ask and the effectiveness of asking about alcohol use, and the least positive beliefs about women's knowledge about alcohol use and discomfort associated with asking about alcohol use in pregnancy. Midwives' beliefs about their role and the effectiveness of asking were most strongly associated with the intention to ask all pregnant women about alcohol use during pregnancy (r = -0.59, p < 0.001 and r = -0.52, p < 0.001). CONCLUSIONS: Our analysis has identified key constructs underlying midwives' beliefs about the assessment of alcohol use during pregnancy. The AAA Scale provides a basis for improved clarity and consistency in the conceptualisation and measurement of midwives' beliefs which can be used to enhance our understanding of factors influencing midwives' ability to deliver interventions to prevent alcohol use during pregnancy. The constructs identified in this exploratory analysis require confirmatory analysis to support their validity and generalizability.

Midwives' knowledge, attitudes and practice about alcohol exposure and the risk of fetal alcohol spectrum disorder.

BACKGROUND: Midwives are an influential profession and a key group in informing women about alcohol consumption in pregnancy and its consequences. There are no current quantitative Australian data on midwives' knowledge, attitudes and practice in relation to alcohol consumption during pregnancy and Fetal Alcohol Spectrum Disorder. We aimed to reduce this knowledge gap by understanding midwives' perceptions of their practice in addressing alcohol consumption during pregnancy. METHODS: This cross-sectional study was conducted at 19 maternity sites across the seven health regions of country Western Australia. A questionnaire was designed following review of the literature and other relevant surveys. Midwifery managers of the maternity sites distributed questionnaires to all midwives working in their line of management. A total of 334 midwives were invited to participate in the research and (n = 245, 73.4%) of these were eligible. RESULTS: The response fraction was (n = 166, 67.8%). Nearly all (n = 151, 93.2%) midwives asked pregnant women about their alcohol consumption during pregnancy and (n = 164, 99.4%) offered advice about alcohol consumption in accordance with the Australian Alcohol Guideline, which states "For women who are pregnant or planning a pregnancy, not drinking is the safest option". Nearly two thirds (n = 104, 64.2%) of the midwives informed pregnant women about the effects of alcohol consumption in pregnancy, they did not always use the recommended AUDIT screening tool (n = 66, 47.5%) to assess alcohol consumption during pregnancy, nor conduct brief intervention when indicated (n = 107, 70.4%). Most midwives endorsed professional development about screening tools (n = 145, 93.5%), brief intervention (n = 144, 92.9%), and alcohol consumption during pregnancy and FASD (n = 144, 92.9%). CONCLUSION: Nearly all midwives in this study asked and advised about alcohol consumption in pregnancy and around two thirds provided information about the effects of alcohol in pregnancy. Our findings support the need for further professional development for midwives on screening and brief intervention. Policy should support midwives' practice to screen for alcohol consumption in pregnancy and offer brief intervention when indicated.

Fetal alcohol spectrum disorder: development of consensus referral criteria for specialist diagnostic assessment in Australia.

BACKGROUND: Fetal alcohol spectrum disorder (FASD) is known to be under-recognised in Australia. The use of standard methods to identify when to refer individuals who may have FASD for specialist assessment could help improve the identification of this disorder. The purpose of this study was to develop referral criteria for use in Australia. METHOD: An online survey about FASD screening and diagnosis in Australia, which included 23 statements describing criteria for referral for fetal alcohol syndrome (FAS) and FASD based on published recommendations for referral in North America, was sent to 139 health professionals who had expertise or involvement in FASD screening or diagnosis. Survey findings and published criteria for referral were subsequently reviewed by a panel of 14 investigators at a consensus development workshop where criteria for referral were developed. RESULTS: Among the 139 health professionals who were sent the survey, 103 (74%) responded, and 90 (65%) responded to the statements on criteria for referral. Over 80% of respondents agreed that referral for specialist evaluation should occur when there is evidence of significant prenatal alcohol exposure, defined as 7 or more standard drinks per week and at least 3 standard drinks on any one day, and more than 70% agreed with 13 of the 16 statements that described criteria for referral other than prenatal alcohol exposure. Workshop participants recommended five independent criteria for referral: confirmed significant prenatal alcohol exposure; microcephaly and confirmed prenatal alcohol exposure; 2 or more significant central nervous system (CNS) abnormalities and confirmed prenatal alcohol exposure; 3 characteristic FAS facial anomalies; and 1 characteristic FAS facial anomaly, growth deficit and 1 or more CNS abnormalities. CONCLUSION: Referral criteria recommended for use in Australia are similar to those recommended in North America. There is a need to develop resources to raise awareness of these criteria among health professionals and evaluate their feasibility, acceptability and capacity to improve the identification of FASD in Australia.

A modified Delphi study of screening for fetal alcohol spectrum disorders in Australia.

BACKGROUND: There is little reliable information on the prevalence of fetal alcohol spectrum disorders (FASD) in Australia and no coordinated national approach to facilitate case detection. The aim of this study was to identify health professionals' perceptions about screening for FASD in Australia. METHOD: A modified Delphi process was used to assess perceptions of the need for, and the process of, screening for FASD in Australia. We recruited a panel of 130 Australian health professionals with experience or expertise in FASD screening or diagnosis. A systematic review of the literature was used to develop Likert statements on screening coverage, components and assessment methods which were administered using an online survey over two survey rounds. RESULTS: Of the panel members surveyed, 95 (73%) responded to the questions on screening in the first survey round and, of these, 81 (85%) responded to the second round. Following two rounds there was consensus agreement on the need for targeted screening at birth (76%) and in childhood (84%). Participants did not reach consensus agreement on the need for universal screening at birth (55%) or in childhood (40%). Support for targeted screening was linked to perceived constraints on service provision and the need to examine the performance, costs and benefits of screening.For targeted screening of high risk groups, we found highest agreement for siblings of known cases of FASD (96%) and children of mothers attending alcohol treatment services (93%). Participants agreed that screening for FASD primarily requires assessment of prenatal alcohol exposure at birth (86%) and in childhood (88%), and that a checklist is needed to identify the components of screening and criteria for referral at birth (84%) and in childhood (90%). CONCLUSIONS: There is an agreed need for targeted but not universal screening for FASD in Australia, and sufficient consensus among health professionals to warrant development and evaluation of standardised methods for targeted screening and referral in the Australian context. Participants emphasised the need for locally-appropriate, evidence-based approaches to facilitate case detection, and the importance of ensuring that screening and referral programs are supported by adequate diagnostic and management capacity.

Recommendations from a consensus development workshop on the diagnosis of fetal alcohol spectrum disorders in Australia.

BACKGROUND: Fetal alcohol spectrum disorders (FASD) are underdiagnosed in Australia, and health professionals have endorsed the need for national guidelines for diagnosis. The aim of this study was to develop consensus recommendations for the diagnosis of FASD in Australia. METHODS: A panel of 13 health professionals, researchers, and consumer and community representatives with relevant expertise attended a 2-day consensus development workshop to review evidence on the screening and diagnosis of FASD obtained from a systematic literature review, a national survey of health professionals and community group discussions. The nominal group technique and facilitated discussion were used to review the evidence on screening and diagnosis, and to develop consensus recommendations for the diagnosis of FASD in Australia. RESULTS: The use of population-based screening for FASD was not recommended. However, there was consensus support for the development of standard criteria for referral for specialist diagnostic assessment. Participants developed consensus recommendations for diagnostic categories, criteria and assessment methods, based on the adaption of elements from both the University of Washington 4-Digit Diagnostic Code and the Canadian guidelines for FASD diagnosis. Panel members also recommended the development of resources to: facilitate consistency in referral and diagnostic practices, including comprehensive clinical guidelines and assessment instruments; and to support individuals undergoing assessment and their parents or carers. CONCLUSIONS: These consensus recommendations provide a foundation for the development of guidelines and other resources to promote consistency in the diagnosis of FASD in Australia. Guidelines for diagnosis will require review and evaluation in the Australian context prior to national implementation as well as periodic review to incorporate new knowledge.

Involving consumers and the community in the development of a diagnostic instrument for fetal alcohol spectrum disorders in Australia.

BACKGROUND: Australia's commitment to consumer and community participation in health and medical research has grown over the past decade. Participatory research models of engagement are the most empowering for consumers. METHODS: As part of a project to develop a diagnostic instrument for fetal alcohol spectrum disorders (FASD) in Australia (FASD Project), the Australian FASD Collaboration (Collaboration), including a consumer advocate and two consumer representatives, was established. On completion of the FASD Project an on-line survey of Collaboration members was conducted to assess their views on consumer involvement. Women in the community were also invited to participate in Community Conversations to discuss real life situations regarding communications with health professionals about alcohol and pregnancy. Community Conversation feedback was analysed qualitatively and attendees were surveyed about their views of the Community Conversation process. RESULTS: The on-line survey was completed by 12 members of the Collaboration (71%). Consumer and community participation was considered important and essential, worked well, and was integral to the success of the project. The 32 women attending the Community Conversations generated 500 statements that made reference to prevention, how information and messages are delivered, and appropriate support for women. Nearly all the attendees at the Community Conversations (93%) believed that they had an opportunity to put forward their ideas and 96% viewed the Community Conversations as a positive experience. CONCLUSIONS: The successful involvement of consumers and the community in the FASD Project can be attributed to active consumer and community participation, which included continued involvement throughout the project, funding of participation activities, and an understanding of the various contributions by the Collaboration members.

Evaluating an intervention of telehealth education and simulation for advanced practice registered nurse students: A single group comparison study.

As healthcare delivery continues to evolve and expand, nurse educators must prepare advanced practice registered nursing (APRN) students to use telehealth technology safely, effectively, and confidently. The aims of this study were to describe APRN students' beliefs and confidence regarding the delivery of care via telehealth in their future practice. To evaluate these aims, a single group comparison study was conducted. APRN students received an intervention comprised of multimodal telehealth instruction, which involved the simulated application of telehealth with standardized patients. Students' beliefs regarding telehealth did not significantly change between the pre- and post-intervention, in which all areas were rated high pre-intervention. Students reported an increase in their perception and confidence post-intervention. Integration of telehealth into the APRN curriculum is essential to instil knowledge and confidence as healthcare technology advances.

Health professionals' perceptions about the adoption of existing guidelines for the diagnosis of fetal alcohol spectrum disorders in Australia.

BACKGROUND: Despite the availability of five guidelines for the diagnosis of fetal alcohol spectrum disorders (FASD), there is no national endorsement for their use in diagnosis in Australia. In this study we aimed to describe health professionals' perceptions about the adoption of existing guidelines for the diagnosis of FASD in Australia and identify implications for the development of national guidelines. METHODS: We surveyed 130 Australian and 9 international health professionals with expertise or involvement in the screening or diagnosis of FASD. An online questionnaire was used to evaluate participants' familiarity with and use of five existing diagnostic guidelines for FASD, and to assess their perceptions about the adoption of these guidelines in Australia. RESULTS: Of the 139 participants surveyed, 84 Australian and 8 international health professionals (66.2%) responded to the questions on existing diagnostic guidelines. Participants most frequently reported using the University of Washington 4-Digit Diagnostic Code (27.2%) and the Canadian guidelines (18.5%) for diagnosis. These two guidelines were also most frequently recommended for adoption in Australia: 32.5% of the 40 participants who were familiar with the University of Washington 4-Digit Diagnostic Code recommended adoption of this guideline in Australia, and 30.8% of the 26 participants who were familiar with the Canadian guidelines recommended adoption of this guideline in Australia. However, for the majority of guidelines examined, most participants were unsure whether they should be adopted in Australia. The adoption of existing guidelines in Australia was perceived to be limited by: their lack of evidence base, including the appropriateness of established reference standards for the Australian population; their complexity; the need for training and support to use the guidelines; and the lack of an interdisciplinary and interagency model to support service delivery in Australia. CONCLUSIONS: Participants indicated some support for the adoption of the University of Washington or Canadian guidelines for FASD diagnosis; however, concerns were raised about the adoption of these diagnostic guidelines in their current form. Australian diagnostic guidelines will require evaluation to establish their validity in the Australian context, and a comprehensive implementation model is needed to facilitate improved diagnostic capacity in Australia.

Fetal Alcohol Spectrum Disorders: Using Knowledge, Attitudes and Practice of Justice Professionals to Support their Educational Needs.

BACKGROUND: People with Fetal Alcohol Spectrum Disorders (FASD) can be involved in high risk, socially unacceptable and harmful behaviours and are at high risk of engaging with the justice system. OBJECTIVE: To obtain baseline data on Western Australian justice professionals' knowledge, attitudes and practice relating to FASD to inform the development of FASD resources. METHODS: Cross sectional study using on-line survey methods, descriptive analysis of quantitative data and content analysis methods for qualitative data. RESULTS: 1873 people were invited to complete the survey. A total of 427 (23%) judicial officers, lawyers, corrective services personnel and police completed the survey. The majority had heard of Fetal Alcohol Syndrome (85%) but were less familiar with FASD (60%). Only 16% of respondents identified the key features of FASD as permanent and only 48.4% considered psychological difficulties as important. The majority of legal and judicial officers and approximately half the police officers considered that knowledge about FASD was very relevant to their work. CONCLUSION: There was widespread agreement of the need for more information and training about FASD to optimise outcomes for people with, or suspected of having a FASD, engaging with the justice system.

Evaluation of plasma resistant hollow fiber membranes for artificial lungs.

Hollow fiber membranes (HFMs) used in artificial lungs (oxygenators) undergo plasma leakage (or wetting) in which blood plasma slowly fills the pores of the fiber wall, plasma leaks into gas pathways, and overall gas exchange decreases. To overcome this problem plasma resistant fibers are being developed that are skinned asymmetric or composite symmetric versions of microporous oxygenator fibers. This report evaluates several candidate plasma resistant HFMs in terms of their gas permeance and plasma resistance as measured in a surfactant wet out test. Five candidate fibers were compared with each other and with a control fiber. CO2 and O2 gas permeance (in ml/s/cm2/cm Hg) in the plasma resistant fibers ranged from 3.15E-04 to 1.71E-03 and 3.40E-04 to 1.08E-03, respectively, compared with 1.62E-02 and 1.77E-02 for the control fiber. Maximum dye bleed through for the plasma resistant fibers in the forced wet out test were significantly less than for the control fiber. CO2 gas permeance of a plasma resistant fiber imposes the greatest constraint upon artificial lung design for sufficient gas exchange. However, our results suggest sufficient plasma resistance can be achieved using special skinned and composite HFMs while maintaining an acceptable CO2 gas permeance for a broad range of artificial lung applications.

Consensus diagnostic criteria for fetal alcohol spectrum disorders in Australia: a modified Delphi study.

OBJECTIVE: To evaluate health professionals' agreement with components of published diagnostic criteria for fetal alcohol spectrum disorders (FASD) in order to guide the development of standard diagnostic guidelines for Australia. DESIGN: A modified Delphi process was used to assess agreement among health professionals with expertise or experience in FASD screening or diagnosis. An online survey, which included 36 Likert statements on diagnostic methods, was administered over two survey rounds. For fetal alcohol syndrome (FAS), health professionals were presented with concepts from the Institute of Medicine (IOM), University of Washington (UW), Centers for Disease Control (CDC), revised IOM and Canadian diagnostic criteria. For partial FAS (PFAS), alcohol-related neurodevelopmental disorder (ARND), and alcohol-related birth defects (ARBD), concepts based on the IOM and the Canadian diagnostic criteria were compared. SETTING/PARTICIPANTS: 130 Australian and 9 international health professionals. RESULTS: Of 139 health professionals invited to complete the survey, 103 (74.1%) responded, and 74 (53.2%) completed one or more questions on diagnostic criteria. We found consensus agreement among participants on the diagnostic criteria for FAS, with the UW criteria most commonly endorsed when compared with all other published criteria for FAS. When health professionals were presented with concepts based on the Canadian and IOM diagnostic criteria, we found consensus agreement but no clear preference for either the Canadian or IOM criteria for the diagnosis of PFAS, and no consensus agreement on diagnostic criteria for ARND. We also found no consensus on the IOM diagnostic criteria for ARBD. CONCLUSIONS: Participants indicated clear support for use of the UW diagnostic criteria for FAS in Australia. These findings should be used to develop guidelines to facilitate improved awareness of, and address identified gaps in the infrastructure for, FASD diagnosis in Australia.

Automated neuropsychological assessment metrics (ANAM) and Woodcock-Johnson III Tests of Cognitive Ability: a concurrent validity study.

This study examines the relationship between a computerized neuropsychological assessment battery, the Automated Neuropsychological Assessment Metrics (ANAM) and a widely used ability measure, Woodcock-Johnson III Tests of Cognitive Ability (WJ-III). Results indicated substantial relationship between the ANAM throughput (accuracy/response time) scores and the WJ-III Cognitive Efficiency cluster. An unexpectedly strong relationship was evident between accuracy scores on the ANAM Logical Reasoning scale and the WJ-III General Intellectual Ability score, purporting to measure the g factor. The findings support the viability of the ANAM as a time- and cost-effective tool for appraisal of cognitive function.

An NH2-terminal multi-basic RKR motif is required for the ATP-dependent regulation of hIK1.

We previously demonstrated that the ATP/PKA-dependent activation of the human intermediate conductance, Ca2+-activated K+ channel, hIK1, is dependent upon a C-terminal motif. The NH2-terminus of hIK1 contains a multi-basic 13RRRKR17 motif, known to be important in the trafficking and function of ion channels. While individual mutations within this domain have no effect on channel function, the triple mutation (15RKR17/AAA), as well as additional double mutations, result in a near complete loss of functional channels, as assessed by whole-cell patch-clamp. However, cell-surface immunoprecipitation studies confirmed expression of these mutated channels at the plasma membrane. To elucidate the functional consequences of the (15)RKR(17)/AAA mutation we performed inside-out patch clamp recordings where we observed no difference in Ca2+ affinity between the wild-type and mutated channels. However, in contrast to wild-type hIK1, channels expressing the 15RKR17/AAA mutation exhibited rundown, which could not be reversed by the addition of ATP. Wild-type hIK1 channel activity was reduced by alkaline phosphatase both in the presence and absence of ATP, indicative of a phosphorylation event, whereas the 15RKR17/AAA mutation eliminated this effect of alkaline phosphatase. Further, single channel analysis demonstrated that the 15RKR17/AAA mutation resulted in a four-fold lower channel open probability (P(o)), in the presence of saturating Ca2+ and ATP, compared to wild-type hIK1. In conclusion, these results represent the first demonstration for a role of the NH2-terminus in the second messenger-dependent regulation of hIK1 and, in combination with our previous findings, suggest that this regulation is dependent upon a close NH2/C-terminal association.

Role of an S4-S5 linker lysine in the trafficking of the Ca(2+)-activated K(+) channels IK1 and SK3.

We have investigated the role of the S4-S5 linker in the trafficking of the intermediate (human (h) IK1) and small (rat SK3) conductance K(+) channels using a combination of patch-clamp, protein biochemical, and immunofluorescence-based techniques. We demonstrate that a lysine residue (Lys(197)) located on the intracellular loop between the S4 and S5 domains is necessary for the correct trafficking of hIK1 to the plasma membrane. Mutation of this residue to either alanine or methionine precluded trafficking of the channel to the membrane, whereas the charge-conserving arginine mutation had no effect on channel localization or function. Immunofluorescence localization demonstrated that the K197A mutation resulted in a channel that was primarily retained in the endoplasmic reticulum, and this could not be rescued by incubation at 27 degrees C. Furthermore, immunoblot analysis revealed that the K197A mutation was overexpressed compared with wild-type hIK1 and that this was due to a greatly diminished rate of channel degradation. Co-immunoprecipitation studies demonstrated that the K197A mutation did not preclude multimer formation. Indeed, the K197A mutation dramatically suppressed expression of wild-type hIK1 at the cell surface. Finally, mutation of this conserved lysine in rat SK3 similarly resulted in a channel that failed to correctly traffic to the plasma membrane. These results are the first to demonstrate a critical role for the S4-S5 linker in the trafficking and/or function of IK and SK channels.

Release of ATP during host cell killing by enteropathogenic E. coli and its role as a secretory mediator.

Enteropathogenic Escherichia coli (EPEC) causes severe, watery diarrhea in children. We investigated ATP release during EPEC-mediated killing of human cell lines and whether released adenine nucleotides function as secretory mediators. EPEC triggered a release of ATP from all human cell lines tested: HeLa, COS-7, and T84 (colon cells) as measured using a luciferase kit. Accumulation of ATP in the supernatant medium was enhanced if an inhibitor of 5'-ectonucleotidase was included and was further enhanced if an ATP-regenerating system was added. In the presence of the inhibitor/regenerator, ATP concentrations in the supernatant medium reached 1.5-2 microM 4 h after infection with wild-type EPEC strains. In the absence of the inhibitor/regenerator system, extracellular ATP was rapidly broken down to ADP, AMP, and adenosine. Conditioned medium from EPEC-infected cells triggered a brisk chloride secretory response in intestinal tissues studied in the Ussing chamber (rabbit distal colon and T84 cell monolayers), whereas conditioned medium from uninfected cells and sterile filtrates of EPEC bacteria did not. The short-circuit current response to EPEC-conditioned medium was completely reversed by adenosine receptor blockers, such as 8-(p-sulfophenyl)-theophylline and MRS1754. EPEC killing of host cells releases ATP, which is broken down to adenosine, which in turn stimulates secretion via apical adenosine A2b receptors. These findings provide new insight into how EPEC causes watery diarrhea.

Role of the NH2 terminus in the assembly and trafficking of the intermediate conductance Ca2+-activated K+ channel hIK1.

The role of the NH(2)-terminal leucine zipper and dileucine motifs of hIK1 in the assembly, trafficking, and function of the channel was investigated using cell surface immunoprecipitation, co-immunoprecipitation (Co-IP), immunoblot, and whole-cell patch clamp techniques. Mutation of the NH(2)-terminal leucine zipper at amino acid positions 18 and 25 (L18A/L25A) resulted in a complete loss of steady-state protein expression, cell surface expression, and whole-cell current density. Inhibition of proteasomal degradation with lactacystin restored L18A/L25A protein expression, although this channel was not expressed at the cell surface as assessed by cell surface immunoprecipitation and whole-cell patch clamp. In contrast, inhibitors of lysosomal degradation (leupeptin/pepstatin) and endocytosis (chloroquine) had little effect on L18A/L25A protein expression or localization. Further studies confirmed the rapid degradation of this channel, having a time constant of 19.0 +/- 1.3 min compared with 3.2 +/- 0.8 h for wild type hIK1. Co-expression studies demonstrated that the L18A/L25A channel associates with wild type channel, thereby attenuating its expression at the cell surface. Co-IP studies confirmed this association. However, L18A/L25A channels failed to form homotetrameric channels, as assessed by Co-IP, suggesting the NH(2) terminus plays a role in tetrameric channel assembly. As with the leucine zipper, mutation of the dileucine motif to alanines, L18A/L19A, resulted in a near complete loss in steady-state protein expression with the protein being similarly targeted to the proteasome for degradation. In contrast to our results on the leucine zipper, however, both chloroquine and growing the cells at the permissive temperature of 27 degrees C restored expression of L18A/L19A at the cell surface, suggesting that the defect in the channel trafficking is the result of a subtle folding error. In conclusion, we demonstrate that the NH(2) terminus of hIK1 contains overlapping leucine zipper and dileucine motifs essential for channel assembly and trafficking to the plasma membrane.

Trafficking of the Ca2+-activated K+ channel, hIK1, is dependent upon a C-terminal leucine zipper.

We demonstrate that the C-terminal truncation of hIK1 results in a loss of functional channels. This could be caused by either (i) a failure of the channel to traffic to the plasma membrane or (ii) the expression of non-functional channels. To delineate among these possibilities, a hemagglutinin epitope was inserted into the extracellular loop between transmembrane domains S3 and S4. Surface expression and channel function were measured by immunofluorescence, cell surface immunoprecipitation, and whole-cell patch clamp techniques. Although deletion of the last 14 amino acids of hIK1 (L414STOP) had no effect on plasma membrane expression and function, deletion of the last 26 amino acids (K402STOP) resulted in a complete loss of membrane expression. Mutation of the leucine heptad repeat ending at Leu(406) (L399A/L406A) completely abrogated membrane localization. Additional mutations within the heptad repeat (L385A/L392A, L392A/L406A) or of the a positions (I396A/L403A) resulted in a near-complete loss of membrane-localized channel. In contrast, mutating individual leucines did not compromise channel trafficking or function. Both membrane localization and function of L399A/L406A could be partially restored by incubation at 27 degrees C. Co-immunoprecipitation studies demonstrated that leucine zipper mutations do not compromise multimer formation. In contrast, we demonstrated that the leucine zipper region of hIK1 is capable of co-assembly and that this is dependent upon an intact leucine zipper. Finally, this leucine zipper is conserved in another member of the gene family, SK3. However, mutation of the leucine zipper in SK3 had no effect on plasma membrane localization or function. In conclusion, we demonstrate that the C-terminal leucine zipper is critical to facilitate correct folding and plasma membrane trafficking of hIK1, whereas this function is not conserved in other gene family members.