Minimally Invasive Cubital Tunnel Release Utilizing Lighted Retractors: A Study of Residents Novel to this Technique Utilizing a Cadaveric Model.

The purpose of this study was to evaluate whether a minimally-invasive cubital tunnel release using lighted retractors could be performed safely and completely by residents with no prior training in this technique. Ten residents participated in the study. Postoperative dissection of the specimens was performed utilizing a detailed checklist and global rating scale to evaluate the completeness of release as well as presence of neurologic injury. Performance of residents was compared. Rho correlation analysis was used to verify validity of the assessment tools. Training year most strongly correlated with Global Rating Scale assessment values. There was a trend correlating training year with faster surgical times, and Detailed Checklist scores. Validation measurements showed strong correlations between the pass/fail grade and the Detailed Checklist and the Global Rating Scale. Complete release of the ulnar nerve in situ utilizing lighted retractors can be performed with minimal training or experience. (Journal of Surgical Orthopaedic Advances 32(3):193-198, 2023).

THYROID SCREENING AND RELIABILITY OF RADIATION THYROID DOSES FOR THE BELARUSIAN IN UTERO COHORT.

OBJECTIVE: To describe the status and results of thyroid disease screening and assessment of reliability of radiationthyroid doses in the Belarusian in utero cohort of 2,965 individuals exposed to Chernobyl (Chornobyl) fallout. MATERIALS AND METHODS: Thyroid screening examinations are currently underway including thyroid palpation by anendocrinologist, ultrasonographic examination by an ultrasonographer and analysis of blood samples for diagnosisof hypo- and hyperthyroidism, autoimmune thyroiditis, thyroid function tests (thyroid-stimulating hormone [TSH],thyroxine [T4], thyroid peroxidase antibody [anti-TPO], and thyroglobulin antibodies [anti-TG]). Reliability of (i)information from 780 pairs of questionnaires obtained during the first and second interviews of the mothers and (ii)thyroid doses, which were calculated for the cohort members using this information, is evaluated. RESULTS: As of 15 August 2021, 1,267 in utero exposed study subjects had been screened. A single thyroid nodule wasdiagnosed in 167 persons (13.2 % of the total) and multiple thyroid nodules in 101 persons (8.0 %): 189 (14.9 %)persons had nodules detected for the first time at the screening while 79 (6.2 %) persons had nodules detected pre-viously (pre-screening nodules). Fifty-nine out of 268 subjects (22.0 %) with a suspicious thyroid nodule werereferred to fine needle aspiration biopsy, and among them 33 (55.9 %) were biopsied. Reasonable agreement wasobserved for modelqbased doses calculated for the Belarusian in utero cohort members using data from the two inter-views (Spearman's rank-correlation coefficient rs = 0.74, p < 0.001), while measurementqbased doses yielded almost per-fect agreement (rs = 0.99, p < 0.001). CONCLUSIONS: During the thyroid screening, at least one thyroid nodule was identified in 268 of 1,267 (21.2 %) inutero exposed cohort members. Seven thyroid cancer cases were identified in the cohort, including 5 pre-screeningcases and 2 cases detected during the screening. Ongoing research on this unique cohort will provide importantinformation on adverse health effects following prenatal and postnatal exposure to radioiodine and radiocesium iso-topes, for which available epidemiological data are scant.

The cost effectiveness of vancomycin for preventing infections after shoulder arthroplasty: a break-even analysis.

BACKGROUND: Increasing methicillin resistance and recognition of Propionibacterium acnes as a cause of infection in shoulder arthroplasty has led to the adoption of local vancomycin powder application as a more effective method to prevent expensive periprosthetic infections. However, no study has analyzed the cost effectiveness of vancomycin powder for preventing infection after shoulder replacement. METHODS: Cost data for infection-related care of 16 patients treated for deep periprosthetic shoulder infection was collected from our institution for the break-even analysis. An equation was developed and applied to the data to determine how effective vancomycin powder would need to be at reducing a baseline infection rate to make prophylactic use cost effective. RESULTS: The efficacy of vancomycin (absolute risk reduction [ARR]) was evaluated at different unit costs, baseline infection rates, and average costs of treating infection. We determined vancomycin to be cost effective if the initial infection rate decreased by 0.04% (ARR). Using the current costs of vancomycin reported in the literature (range: $2.50/1000 mg to $44/1000 mg), we determined vancomycin to be cost effective with an ARR range of 0.01% at a cost of $2.50/1000 mg to 0.19% at $44/1000 mg. Baseline infection rate does not influence the ARR obtained at any specific cost of vancomycin or the cost of treating infection. CONCLUSIONS: We have derived and used a break-even equation to assess efficacy of prophylactic antibiotics during shoulder surgery. We further demonstrated the prophylactic administration of local vancomycin powder during shoulder arthroplasty to be a highly cost-effective practice.

Non-radiation risk factors for leukemia: A case-control study among chornobyl cleanup workers in Ukraine.

BACKGROUND: Occupational and environmental exposure to chemicals such as benzene has been linked to increased risk of leukemia. Cigarette smoking and alcohol consumption have also been found to affect leukemia risk. Previous analyses in a large cohort of Chornobyl clean-up workers in Ukraine found significant radiation-related increased risk for all leukemia types. We investigated the potential for additional effects of occupational and lifestyle factors on leukemia risk in this radiation-exposed cohort. METHODS: In a case-control study of chronic lymphocytic and other leukemias among Chornobyl cleanup workers, we collected data on a range of non-radiation exposures. We evaluated these and other potential risk factors in analyses adjusting for estimated bone marrow radiation dose. We calculated Odds Ratios and 95% Confidence Intervals in relation to lifestyle factors and occupational hazards. RESULTS: After adjusting for radiation, we found no clear association of leukemia risk with smoking or alcohol but identified a two-fold elevated risk for non-CLL leukemia with occupational exposure to petroleum (OR=2.28; 95% Confidence Interval 1.13, 6.79). Risks were particularly high for myeloid leukemias. No associations with risk factors other than radiation were found for chronic lymphocytic leukemia. CONCLUSIONS: These data - the first from a working population in Ukraine - add to evidence from several previous reports of excess leukemia morbidity in groups exposed environmentally or occupationally to petroleum or its products.

Non-thyroid cancer in Northern Ukraine in the post-Chernobyl period: Short report.

The Chernobyl nuclear power plant accident in Ukraine in 1986 led to widespread radioactive releases into the environment - primarily of radioiodines and cesium - heavily affecting the northern portions of the country, with settlement-averaged thyroid doses estimated to range from 10 mGy to more than 10 Gy. The increased risk of thyroid cancer among exposed children and adolescents is well established but the impact of radioactive contamination on the risk of other types of cancer is much less certain. To provide data on a public health issue of major importance, we have analyzed the incidence of non-thyroid cancers during the post-Chernobyl period in a well-defined cohort of 13,203 individuals who were <18 years of age at the time of the accident. The report is based on standardized incidence ratio (SIR) analysis of 43 non-thyroid cancers identified through linkage with the National Cancer Registry of Ukraine for the period 1998 through 2009. We compared the observed and expected number of cases in three cancer groupings: all solid cancers excluding thyroid, leukemia, and lymphoma. Our analyses found no evidence of a statistically significant elevation in cancer risks in this cohort exposed at radiosensitive ages, although the cancer trends, particularly for leukemia (SIR=1.92, 95% confidence interval: 0.69; 4.13), should continue to be monitored.

Iodine-131 dose-dependent gene expression: alterations in both normal and tumour thyroid tissues of post-Chernobyl thyroid cancers.

BACKGROUND: A strong, consistent association between childhood irradiation and subsequent thyroid cancer provides an excellent model for studying radiation carcinogenesis. METHODS: We evaluated gene expression in 63 paired RNA specimens from frozen normal and tumour thyroid tissues with individual iodine-131 (I-131) doses (0.008-8.6 Gy, no unirradiated controls) received from Chernobyl fallout during childhood (Ukrainian-American cohort). Approximately half of these randomly selected samples (32 tumour/normal tissue RNA specimens) were hybridised on 64 whole-genome microarrays (Agilent, 4 × 44 K). Associations between I-131 dose and gene expression were assessed separately in normal and tumour tissues using Kruskal-Wallis and linear trend tests. Of 155 genes significantly associated with I-131 after Bonferroni correction and with ≥2-fold increase per dose category, we selected 95 genes. On the remaining 31 RNA samples these genes were used for validation purposes using qRT-PCR. RESULTS: Expression of eight genes (ABCC3, C1orf9, C6orf62, FGFR1OP2, HEY2, NDOR1, STAT3, and UCP3) in normal tissue and six genes (ANKRD46, CD47, HNRNPH1, NDOR1, SCEL, and SERPINA1) in tumour tissue was significantly associated with I-131. PANTHER/DAVID pathway analyses demonstrated significant over-representation of genes coding for nucleic acid binding in normal and tumour tissues, and for p53, EGF, and FGF signalling pathways in tumour tissue. CONCLUSION: The multistep process of radiation carcinogenesis begins in histologically normal thyroid tissue and may involve dose-dependent gene expression changes.

The Chernobyl accident--an epidemiological perspective.

Twenty-five years have passed since radioactive releases from the Chernobyl nuclear accident led to the exposure of millions of people in Europe. Studies of affected populations have provided important new data on the links between radiation and cancer-particularly the risk of thyroid tumours from exposure to iodine isotopes-that are important not only for a fuller scientific understanding of radiation effects, but also for radiation protection. It is now well documented that children and adolescents exposed to radioiodines from Chernobyl fallout have a sizeable dose-related increase in thyroid cancer, with the risk greatest in those youngest at exposure and with a suggestion that deficiency in stable iodine may increase the risk. Data on thyroid cancer risks to other age groups are somewhat less definitive. In addition, there have been reported increases in incidence and mortality from non-thyroid cancers and non-cancer end points. Although some studies are difficult to interpret because of methodological limitations, recent investigations of Chernobyl clean-up workers ('liquidators') have provided evidence of increased risks of leukaemia and other haematological malignancies and of cataracts, and suggestions of an increase in the risk of cardiovascular diseases, following low doses and low dose rates of radiation. Further careful follow-up of these populations, including the establishment and long-term support of life-span study cohorts, could provide additional important information for the quantification of radiation risks and the protection of persons exposed to low doses of radiation.

Thyroid cancer risk in Belarus among children and adolescents exposed to radioiodine after the Chornobyl accident.

BACKGROUND: Previous studies showed an increased risk of thyroid cancer among children and adolescents exposed to radioactive iodines released after the Chornobyl (Chernobyl) accident, but the effects of screening, iodine deficiency, age at exposure and other factors on the dose-response are poorly understood. METHODS: We screened 11 970 individuals in Belarus aged 18 years or younger at the time of the accident who had estimated (131)I thyroid doses based on individual thyroid activity measurements and dosimetric data from questionnaires. The excess odds ratio per gray (EOR/Gy) was modelled using linear and linear-exponential functions. RESULTS: For thyroid doses <5 Gy, the dose-response was linear (n=85; EOR/Gy=2.15, 95% confidence interval: 0.81-5.47), but at higher doses the excess risk fell. The EOR/Gy was significantly increased among those with prior or screening-detected diffuse goiter, and larger for men than women, and for persons exposed before age 5 than those exposed between 5 and 18 years, although not statistically significant. A somewhat higher EOR/Gy was estimated for validated pre-screening cases. CONCLUSION: 10-15 years after the Chornobyl accident, thyroid cancer risk was significantly increased among individuals exposed to fallout as children or adolescents, but the risk appeared to be lower than in other Chornobyl studies and studies of childhood external irradiation.

A screening study of thyroid cancer and other thyroid diseases among individuals exposed in utero to iodine-131 from Chernobyl fallout.

BACKGROUND: Like stable iodine, radioiodines concentrate in the thyroid gland, increasing thyroid cancer risk in exposed children. Data on exposure to the embryonic/fetal thyroid are rare, raising questions about use of iodine 131 (I-131) in pregnant women. We present here estimated risks of thyroid disease from exposure in utero to I-131 fallout from the Chernobyl nuclear accident. METHODS: We conducted a cross-sectional thyroid screening study (palpation, ultrasound, thyroid hormones, and, if indicated, fine needle aspiration) from 2003 to 2006. Participants were 2582 mother-child pairs from Ukraine in which the mother had been pregnant at the time of the accident on April 26, 1986, or 2 months after the time during which I-131 fallout was still present (1494 from contaminated areas, 1088 in the comparison group). Individual cumulative in utero thyroid dose estimates were derived from estimated I-131 activity in the mother's thyroid (mean 72 mGy; range 0-3230 mGy). RESULTS: There were seven cases of thyroid carcinoma and one case of Hurthle cell neoplasm identified as a result of the screening. Whereas the estimated excess odds ratio per gray for thyroid carcinoma was elevated (excess odds ratio per gray 11.66), it was not statistically significant (P = 0.12). No radiation risks were identified for other thyroid diseases. CONCLUSION: Our results suggest that in utero exposure to radioiodines may have increased the risk of thyroid carcinoma approximately 20 yr after the Chernobyl accident, supporting a conservative approach to medical uses of I-131 during pregnancy.

The Ukrainian-American study of leukemia and related disorders among Chornobyl cleanup workers from Ukraine: I. Study methods.

There are relatively few data on the risk of leukemia among those exposed to external radiation during cleanup operations after the Chornobyl nuclear accident, and results have not been consistent. To investigate this further, we assembled a cohort of 110,645 male cleanup workers from Ukraine and identified cases of leukemia occurring during the period 1986 to 2000. Detailed interviews were conducted and individual bone marrow doses estimated using a new time-and-motion method known as RADRUE described in companion paper II. For the initial analyses we used a nested case-control approach with a minimum of five controls per case, matched for year of birth, oblast (region) of registration, and residence. All identified cases were reviewed by an international panel of experts; 87 of 111 were confirmed. The dose-response analysis and results are given in companion paper III. As background, we describe herein the design, procedures, outcome of case finding and confirmation, control selection, dose estimation and interviewing of subjects.

Autoimmune thyroiditis and exposure to iodine 131 in the Ukrainian cohort study of thyroid cancer and other thyroid diseases after the Chornobyl accident: results from the first screening cycle (1998-2000).

CONTEXT: Due to the Chornobyl accident, millions were exposed to radioactive isotopes of iodine and some received appreciable iodine 131 (131I) doses. A subsequent increase in thyroid cancer has been largely attributed to this exposure, but evidence concerning autoimmune thyroiditis (AIT) remains inconclusive. OBJECTIVE: The objective of the study was to quantify risk of AIT after 131I exposure. DESIGN/SETTING/PARTICIPANTS: Baseline data were collected from the first screening cycle (1998-2000) of a large cohort of radiation-exposed individuals (n = 12,240), residents of contaminated, iodine-deficient territories of Ukraine. Study individuals were under the age of 18 yr on April 26, 1986, and had thyroid radioactivity measurements made shortly after the accident. OUTCOMES: AIT was defined a priori based on various combinations of elevated antibodies to thyroid peroxidase (ATPO), TSH, and clinical findings; elevated ATPO were considered to be an indicator of thyroid autoimmunity. RESULTS: No significant association was found between 131I thyroid dose estimates and AIT, but prevalence of elevated ATPO demonstrated a modest, significant association with 131I that was well described by several concave models. This relationship was apparent in individuals with moderately elevated ATPO and euthyroid, thyroid disease-free individuals. CONCLUSIONS: Twelve to 14 yr after the Chornobyl accident, no radiation-related increase in prevalence of AIT was found in a large cohort study, the first in which 131I thyroid doses were estimated using individual radioactivity measurements. However, a dose-response relationship with ATPO prevalence raises the possibility that clinically important changes may occur over time. Thus, further follow-up and analysis of prospective data in this cohort are necessary.

Iodine excretion in regions of Ukraine affected by the Chornobyl Accident: experience of the Ukrainian-American cohort study of thyroid cancer and other thyroid diseases.

Urinary iodine concentrations were measured in 11,926 subjects who are participants in the Ukrainian-American Cohort Study of Thyroid Cancer and Other Thyroid Diseases Following the Chornobyl Accident. Measurements were made in two time periods corresponding to the first and second thyroid screening cycles (1998-2000, 2001-2003). These time periods fall before and after initiation of a government program to increase iodine sufficiency. Median urinary iodine concentrations did increase in the later time period compared to the earlier [47.5 microg/L, 95% confidence interval (CI) 46.5-48.9 microg/L versus 41.7 microg/L, 95% CI 40.4-42.5 microg/L], but levels remained in the mild-to-moderate iodine deficiency range as defined by the World Health Organization (WHO), indicating the need for further efforts at iodination. In both time periods, urinary iodine levels were found to vary by place of residence and were lower in rural compared to urban areas. Iodine status needs to be considered when evaluating risk of thyroid cancer and other thyroid diseases.

Purification, molecular cloning, and sequence analysis of sucrose-6F-phosphate phosphohydrolase from plants.

Sucrose-6(F)-phosphate phosphohydrolase (SPP; EC ) catalyzes the final step in the pathway of sucrose biosynthesis and is the only enzyme of photosynthetic carbon assimilation for which the gene has not been identified. The enzyme was purified to homogeneity from rice (Oryza sativa L.) leaves and partially sequenced. The rice leaf enzyme is a dimer with a native molecular mass of 100 kDa and a subunit molecular mass of 50 kDa. The enzyme is highly specific for sucrose 6(F)-phosphate with a K(m) of 65 microM and a specific activity of 1250 micromol min(-1) mg(-1) protein. The activity is dependent on Mg(2+) with a remarkably low K(a) of 8-9 microM and is weakly inhibited by sucrose. Three peptides from cleavage of the purified rice SPP with endoproteinase Lys-C showed similarity to the deduced amino acid sequences of three predicted open reading frames (ORF) in the Arabidopsis thaliana genome and one in the genome of the cyanobacterium Synechocystis sp. PCC6803, as well as cDNA clones from Arabidopsis, maize, and other species in the GenBank database of expressed sequence tags. The putative maize SPP cDNA clone contained an ORF encoding a 420-amino acid polypeptide. Heterologous expression in Escherichia coli showed that this cDNA clone encoded a functional SPP enzyme. The 260-amino acid N-terminal catalytic domain of the maize SPP is homologous to the C-terminal region of sucrose-phosphate synthase. A PSI-BLAST search of the GenBank database indicated that the maize SPP is a member of the haloacid dehalogenase hydrolase/phosphatase superfamily.

Muscarinic down-regulation of cAMP-stimulated potassium ion secretion by rabbit distal colon.

The sustained effects of the cholinergic agonist carbachol (CCh) on electrolyte transport across the isolated, short-circuited rabbit distal colon were examined in the absence and presence of secretagogue (di-butyryl cyclic-adenosine monophosphate, dB-cAMP). Steady-state, basal absorption of 22Na+, 42K+ (86Rb+), and 36Cl- were not significantly altered by addition of the CCh (10(-4) mmol/l) to the serosal reservoir. Stimulation with dB-cAMP (1.0 mmol/l, serosal) promoted K+ (or Rb+) and Cl- secretion across the colon, without significantly affecting the unidirectional or net fluxes of Na+. Serosal (but not mucosal) addition of CCh to dB-cAMP-stimulated tissues reduced the serosal to mucosal flux of Rb+ (J(Rb)SM) in a concentration-dependent manner with a half-maximum concentration approximately equal 5 micromol/l. Pretreatment with CCh (100 micromol/l, serosal) inhibited dB-cAMP-induced K+ secretion, but had no significant effect on the steady-state unidirectional fluxes of Na+ or Cl-. Serosal histamine (20 micromol/l) also inhibited J(Rb)SM in dB-cAMP-stimulated tissues. Serosal epinephrine (10 micromol/l) promoted a decrease in short-circuit current (Isc) and transepithelial potential (VT) that was mirrored by increases in J(Rb)SM. Both Isc, and VT became more positive and J(Rb)SM was reduced when CCh was added to the epinephrine-stimulated tissues. Serosal muscarine (50 micromol/l) mimicked the CCh-induced inhibition of J(Rb)SM, but serosal nicotine (50 micromol/l) had no effect. In atropine-treated tissues (1 micromol/l, serosal), CCh failed to block dB-cAMP-stimulated increases in J(Rb)SM. The inhibitory action of CCh was observed in tissues that had been pretreated with 50 micromol/l serosal hexamethonium (a ganglionic transmission blocker) or 2 micromol/l serosal tetrodotoxin (a voltage-gated Na+ channel blocker), indicating that the inhibitory action of this cholinergic agonist does not depend on remnant enteric neural pathways. Rubidium ion transport across confluent monolayers of T84 cells was similarly affected by dB-cAMP and CCh, supporting the notion that enteric neural pathways are not required. Serosal charybdotoxin (20 nmol/l) mitigated the inhibitory action of CCh on J(Rb)SM in dB-cAMP-stimulated tissues, suggesting a role for basolateral, Ca2+-dependent K+ channels in the actions of CCh. It is concluded that basolateral muscarinic receptors (and possibly other Ca2+-dependent receptor pathways) of secretory colonocytes mediate the down-regulation of potassium ion secretion by rabbit distal colon, possibly by increasing basolateral membrane K+ conductance.

Using qualitative methods to elicit recall of a critical time period.

The period during and after puberty seems to be important for breast cancer initiation. Because experiences during that time are likely to be influenced by a woman's cultural background, we conducted a pilot study among Hispanic and Caucasian women to elicit their memories of early life events. These data were used to design culture-specific questionnaire modules for the retrospective assessment of peripubertal breast cancer risk factors, using specific strategies to trigger accurate recall. Study subjects were volunteer breast cancer survivors or relatives of survivors. In carrying out this work, we took methods from the social sciences and applied them to a research question in chronic disease epidemiology. We found both qualitative and quantitative differences in recall of peripubertal exposures and experiences between Hispanic and Caucasian subjects. Our preliminary data indicate that in contrast to Caucasian women, Hispanic women consider the church rather than school a touchstone for recalling past events. Under the domain "body development," Hispanic women are more likely to mention menstruation than Caucasian women but less likely to recall changes in body hair and breast development. Caucasian women cited team sports as an important physical activity during the peripubertal period, whereas Hispanic women listed more sedentary games and housework as the main activities. Results of our pilot study support the view that to enhance the validity of retrospective data on peripubertal breast cancer risk factors, it is important to take account of cultural differences. Our experience using qualitative methods to elicit data of this kind in the context of a larger epidemiologic research effort suggests that such innovative approaches are valuable.

Maternal leisure-time exercise and timely delivery.

OBJECTIVES: This study investigated whether, in a general obstetric population, exercise in pregnancy affects the timeliness of delivery. The hypothesis was that maternal exercise would not raise the risk of preterm birth. METHODS: A community cohort of 557 prenatal patients was followed up until the time of delivery. Data were collected on exercise in each trimester: none, low-moderate (< 1000 kcal [4184 kJ]/wk in energy expenditure), or heavy (> or = 1000 kcal/wk). Timely delivery was adopted as an outcome criterion. Thus, in the analysis, a term birth was treated as optimal and survival techniques were used to estimate risks for both preterm and postdates delivery. RESULTS: No association was found between low-moderate exercise and gestational length. Heavier exercise appeared to reduce, rather than raise, the risk of preterm birth. The adjusted relative risk among conditioned heavy exercisers was 0.11 (95% confidence interval = 0.02, 0.81). After term, conditioned heavy exercisers delivered faster than nonexercisers. CONCLUSIONS: The most important finding was the lack of evidence that vigorous maternal exercise is a risk factor for preterm delivery. A promising finding was that conditioned heavy exercisers have timely deliveries.

Women, work, and health.

The U.S. Bureau of National Affairs has conducted several surveys asking women to rate the seriousness of 11 hazards thought to affect female workers. In 1995 the women respondents ranked them in the following order: 1) stress, 2) repetitive motions, 3) AIDS, 4) violence, 5) VDTs, 6) indoor air pollution, 7) hepatitis, 8) injury on the job, 9) reproductive hazards, 10) tuberculosis, and 11) other infectious diseases. A parallel list of 11 hazards thought to affect male workers would look very different. The purpose of this paper is to explore why this is so and what it implies for the occupational health research agenda.

cAMP-dependent sulfate secretion by the rabbit distal colon: a comparison with electrogenic chloride secretion.

The ability of a Cl-secreting epithelium to support net secretion of an anion other than a halide was investigated with 35SO4 flux measurements across the isolated, short-circuited rabbit distal colon. In most experiments, 36Cl fluxes were simultaneously measured to validate the secretory capacity of the tissues. Serosal addition of dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP, 0.5 mM) stimulated a sustained net secretion of SO4 (about -3.0 nmol.cm-2.h-1 from a 0.20 mM solution) via an increase in the serosal-to-mucosal unidirectional flux, whereas Ca ionophore A-23187 (1 microM, serosal) produced a more transient stimulation of SO4 and Cl secretion. Net adenosine 3',5'-cyclic monophosphate (cAMP)-dependent SO4 and Cl secretion were strongly voltage sensitive, principally through the potential dependence of the serosal-to-mucosal fluxes, indicating an electrogenic transport process. Symmetrical replacement of either Na, K, or Cl inhibited cAMP-dependent SO4 secretion, whereas HCO3-free buffers had no effect on SO4 secretion. Serosal bumetanide (50 microM) or furosemide (100 microM) reduced DBcAMP-stimulated SO4 and Cl secretion, whereas serosal 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid or 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (50 microM) blocked DBcAMP-induced SO4 secretion while enhancing net Cl secretion and short-circuit current. Mucosal 5-nitro-2-(3-phenylpropylamino)benzoic acid partially inhibited SO4 secretion and completely inhibited Cl secretion. It is concluded that secretagogue-stimulated SO4 secretion, like Cl secretion, may be an electrogenic process mediated by diffusive efflux through an apical anion conductance. Cellular accumulation of SO4 across the basolateral membrane appears to be achieved by a mechanism that is distinct from that employed by Cl.