Infection in cystic fibrosis: impact of the environment and climate.

In many countries numbers of adults with cystic fibrosis (CF) exceed that of children, with median survival predicted to surpass 50 years. Increasing longevity is, in part, due to intensive therapies including eradication of early infection and suppressive therapies and pulmonary exacerbations. Initial infections with common CF pathogens are thought to arise from the natural environment. We review the impact of climate and environment on infection in CF. Specifically, several studies indicate that higher ambient temperatures, proximity to the equator and the summer season may be linked to the increased prevalence of Pseudomonas aeruginosa in people with CF. The environment may also play an important role in the acquisition of Gram negative organisms other than P. aeruginosa. There is emerging data suggesting that climatic and environmental factors are likely to impact on the risk of infection with NTM and fungi in people which are found extensively throughout the natural environment.

Assessing the sensitivity of habitats to fishing: from seabed maps to sensitivity maps.

In the Welsh part of the Irish Sea, a method was developed for assessing the sensitivity of different seabed habitats to existing fishing activities, across a range of potential fishing intensities. The resistance of 31 habitats and their associated biological assemblage to damage by 14 categories of fishing activity were assessed along with the rate at which each habitat would recover following impact (resilience). Sensitivity was scored based on a combination of the resistance of a habitat to damage and its subsequent rate of recovery. The assessments were based, wherever possible, on scientific literature, with expert judgement used to extrapolate results to habitat and gear combinations not directly examined in the published literature. The resulting sensitivity matrices were then subject to further peer review at a series of workshops. Following consensus on the habitat sensitivity, these data were combined with the most resolved sea-floor habitat maps. These habitat sensitivity maps can help inform the development of site-specific management plans, as well as having a place in spatial planning and aiding managers in developing dialogue with other stakeholders. A case study of their application is provided.

Rapid single-nucleotide polymorphism-based identification of clonal Pseudomonas aeruginosa isolates from patients with cystic fibrosis by the use of real-time PCR and high-resolution melting curve analysis.

Pseudomonas aeruginosa genotyping relies mainly upon DNA fingerprinting methods, which can be subjective, expensive and time-consuming. The detection of at least three different clonal P. aeruginosa strains in patients attending two cystic fibrosis (CF) centres in a single Australian city prompted the design of a non-gel-based PCR method to enable clinical microbiology laboratories to readily identify these clonal strains. We designed a detection method utilizing heat-denatured P. aeruginosa isolates and a ten-single-nucleotide polymorphism (SNP) profile. Strain differences were detected by SYBR Green-based real-time PCR and high-resolution melting curve analysis (HRM10SNP assay). Overall, 106 P. aeruginosa sputum isolates collected from 74 patients with CF, as well as five reference strains, were analysed with the HRM10SNP assay, and the results were compared with those obtained by pulsed-field gel electrophoresis (PFGE). The HRM10SNP assay accurately identified all 45 isolates as members of one of the three major clonal strains characterized by PFGE in two Brisbane CF centres (Australian epidemic strain-1, Australian epidemic strain-2 and P42) from 61 other P. aeruginosa strains from Australian CF patients and two representative overseas epidemic strain isolates. The HRM10SNP method is simple, is relatively inexpensive and can be completed in <3 h. In our setting, it could be made easily available for clinical microbiology laboratories to screen for local P. aeruginosa strains and to guide infection control policies. Further studies are needed to determine whether the HRM10SNP assay can also be modified to detect additional clonal strains that are prevalent in other CF centres.

Effect of the anticoagulant ethylenediamine tetra-acetic acid (EDTA) on the estimation of pharmacokinetic parameters: A case study with tigecycline and ciprofloxacin.

Tigecycline and ciprofloxacin were employed as the model compounds to study the effect of the anticoagulant ethylenediamine tetra-acetic acid (EDTA), which is used during plasma sample preparations, on the determination of pharmacokinetic parameters. The pharmacokinetic parameters were determined in rats following intravenous infusion with blood samples collected in serum separators, with either EDTA- or heparin-coated tubes. The blood-to-plasma (B:P) partition ratio and plasma protein binding were determined in vitro in rat or human blood collected in either EDTA- or heparin-coated tubes. Drug concentrations were quantified by liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS) analysis. In tigecycline-treated rats drug concentrations were twofold lower in EDTA plasma, leading to a twofold lower area under plasma concentration-time curve (AUC) and twofold higher plasma clearance values as compared with those obtained from heparin plasma. No differences were noted in the pharmacokinetic parameters obtained from heparin-treated plasma versus serum. The B:P partition ratio and unbound fraction for tigecycline were significantly higher in EDTA-treated blood. When normalized to the B:P partition ratios, the tigecycline blood clearance values were identical between samples collected in EDTA- or heparin-coated tubes. Similar but smaller differences were observed for ciprofloxacin. It was concluded that EDTA might compete with tigecycline and ciprofloxacin for chelating metal ions and thus affect drug partition between blood and plasma compartments, leading to inaccurate measurement of pharmacokinetic parameters in plasma.

Facilities for chemical decontamination in accident and emergency departments in the United Kingdom.

OBJECTIVE: To audit the facilities for chemical decontamination, with special reference to cyanide poisoning, in all major accident and emergency departments in the UK. METHOD: A simple postal questionnaire was used to audit planning, premises, equipment, protection for staff, and stocks of specific antidotes to cyanide poisoning. RESULTS: 227 questionnaires from 261 departments (87%) were returned and used in the survey. Of the 227 departments who responded, 151 (66%) had a written plan; 168 (74%) departments had premises for decontamination; 55 (24%) were judged to have satisfactory premises; 146 (64%) departments had a shower or hose for decontamination; 60 (26%) departments had a decontamination trolley suitable for "stretcher" patients; 203 (89%) had some protective equipment for staff but only 77 (34%) had complete protection--that is, goggles, chemical resistant clothing, and breathing apparatus. In the authors' opinion only seven (3%) departments had satisfactory premises and equipment to treat "stretcher" patients and full protection for staff. A further 11 (5%) departments were equipped to manage ambulant patients at a similar level. Some 205 (90%) departments stocked one or more antidotes to cyanide and 77 (34%) stocked all four antidotes. Thirty four (15%) departments held all four antidotes to cyanide and had full protection for staff. Only five (2%) departments had satisfactory premises and equipment to treat "stretcher" patients, full protection for staff, and at least three of four antidotes. CONCLUSIONS: Most departments had some equipment for chemical decontamination. However, there were major inconsistencies in the range of equipment held and these limited its usefulness. Only a small minority of departments was satisfactorily equipped to deal with a serious chemical incident.

Effect of chlortetracycline in a trace mineral salt mix on fertility traits in beef cattle females in Florida.

The study objective was to determine the effect of chlortetracycline in an ad libitum trace-mineralized salt mix given to heifers before and(or) during bull exposure on the proportion pregnant and the time to conception in a fixed breeding period. Heifers (n = 768), 13 to 15 mo of age, were individually identified, immunized (Leptospira, Campylobacter fetus), examined (body condition score, vaginal lesion score, BW), and randomly allocated within 2 x 2 factorial blocks of treatments where trace mineral salt with and without chlortetracycline medication was provided in similar but nonadjacent pastures either before and(or) during bull exposure. The chlortetracycline feeding period was about 30 d for each. In the 2 d immediately before bull exposure, heifers were examined (body condition score, vaginal lesion score, reproductive tract evaluation) and reallocated to treatment pastures. Pregnancy was determined by per rectal palpation at 45 d following bull removal. Mineral intake was below that expected for heifer groups and, as a result, chlortetracycline intake was estimated at less than one-third of that targeted. Many heifers were not cycling reproductively at the onset of bull exposure (n = 456, 60.3%, based on a reproductive tract score < 3). Despite these limitations, heifers receiving chlortetracycline treatment before breeding had a pregnancy percentage of 65% (chlortetracycline before and during breeding 67% and chlortetracycline before breeding 61.8%) compared to those receiving no treatment before breeding (53%, P < 0.03; no chlortetracycline before or during breeding 60.4% and chlortetracycline during breeding 47.4%). Heifers receiving chlortetracycline treatment before breeding were 57% more likely to become pregnant than those not treated before breeding. Change in vaginal lesion score was associated with the proportion pregnant, but neither body condition score nor average daily gain were.

Readmission to the intensive care unit after liver transplantation.

OBJECTIVE: We undertook this study to understand the factors at our transplant center that contribute to patients' return to the ICU after their liver transplant and their initial discharge from that unit. Patients who, after liver transplantation, fail discharge from the Intensive Care Unit (ICU) and must be readmitted to that unit may well utilize many more resources than those patients who are well enough to stay out of the ICU. DESIGN: A retrospective review of a prospectively maintained liver transplant research database followed by a retrospective review of (a subgroup) patient charts and contemporaneous controls. SETTING: A large metropolitan tertiary care center and adult liver transplant center. PATIENTS: A total of 1,197 consecutive adult patients who underwent their initial liver transplantation from 1984 to 1996. INTERVENTION: Readmission to the intensive care unit after adult liver transplantation and discharge from that unit. MAIN RESULTS: Only recipient age, pretransplant synthetic function labs (protime and albumin), bilirubin levels, and intraoperative blood product requirements could be statistically linked to the group requiring ICU readmission. The primary etiology for ICU readmission was cardiopulmonary deterioration. Readmission was associated with significantly lower patient and graft survivals. A detailed review of 23 patients transplanted from October 1994 to June 1996 was made, with special emphasis on cardiopulmonary status (hemodynamics, respiratory variables, and chest radiograph findings). This subgroup was compared with 30 temporally matched controls who were not readmitted to the ICU. Intravascular fluid overload and lower inspiratory capacity were significant factors related to ICU readmission. Readmitted patients had a longer hospitalization with higher hospital charges than the control group. CONCLUSIONS: We conclude that the most important means of preventing ICU readmission in liver transplantation patients is to optimize cardiopulmonary function and status. Close monitoring of fluid balance to avoid hypervolemia is essential. Readmitted patients have a greater resource utilization and have lower survival rates.

A prospective evaluation of empiric versus protocol-based sedation and analgesia.

STUDY OBJECTIVE: To compare empiric and protocol-based therapies of sedation and analgesia in terms of pharmacologic cost, effects on mechanical ventilation and intensive care unit (ICU) stay, and quality of sedation and analgesia. DESIGN: Prospective study. SETTING: A 24-bed medical-surgical-neurologic ICU. PATIENTS: Seventy-two patients evaluated during empiric therapy and 86 during protocol-based therapy. INTERVENTION: Assessment of data collected for 4 months before and 5 months after an evidence-based sedation and analgesia protocol was implemented. MEASUREMENTS AND MAIN RESULTS: Protocol adherence rate was 83.7%. The hourly cost (Canadian dollars) of sedation was less with protocol-based therapy ($5.68 +/- 4.27 vs $7.69 +/- 5.29, p<0.01) likely due to increased lorazepam use. Pharmacologic cost savings may be negated since sedation duration tended to be longer (122.7 +/- 142.8 vs 88.0 +/- 94.8 hrs, p<0.1) and extubation may have been delayed (61.6 +/- 97.4 vs 39.1 +/- 54.7 hrs, p=0.13) with protocol use. Duration of ICU stay after sedation was discontinued was not significantly different before and after protocol implementation. With the protocol, however, the percentage of modified Ramsay sedation scores representing discomfort decreased from 22.4 to 11% (p<0.001) and the percentage at a score of 4 increased from 17.2% to 29.6% (p<0.01). The percentage of modified visual analog measurements representing pain decreased from 9.6 to 5.9% (p<0.05) with the protocol. When data were stratified according to duration of sedation, the benefits and delayed extubation associated with protocol-based therapy were limited to patients requiring long-term sedation. CONCLUSION: Compliance with this protocol reduced drug costs and enhanced the quality of sedation and analgesia for patients requiring long-term sedation. Protocol-based therapy with lorazepam may have delayed extubation but did not delay ICU discharge.

Teaching partner-focused questions to individuals who use augmentative and alternative communication to enhance their communicative competence.

A single-subject, multiple-probe experimental design was used to investigate the effect of instruction on the acquisition, generalization, and long-term maintenance of partner-focused questions (i.e., questions about communication partners and their experiences) by individuals who use augmentative and alternative communication (AAC). Six participants who had severe speech impairments and used AAC participated in the study; they ranged in age from 10 to 44 years, had a variety of disabilities, and used a range of AAC systems. Instruction used a least-to-most prompting hierarchy in real-world interactions and during simulations. All of the participants successfully learned to ask partner-focused questions spontaneously in social interactions; they required an average of approximately 6 hours of instruction (range: 3-11 hours). The participants generalized the use of partner-focused questions to new situations in the natural environment and maintained use of partner-focused questions at least 2 months postinstruction; one participant required some "booster" instructional sessions 4 weeks postinstruction to maintain her long-term use of partner-focused questions. The participants all reported high levels of satisfaction with the outcomes of the instructional program, as did their facilitators. Members of the general public, blind to the goals of the study, judged the majority of the participants to be more competent communicators after instruction.

Oral transmucosal fentanyl citrate as an additional premedicant for adult cardiac surgery patients.

OBJECTIVE: To investigate the efficacy of a combination of midazolam and oral transmucosal fentanyl citrate (OTFC) as a preoperative medication for adult cardiac surgery patients compared with the use of midazolam alone. DESIGN: A randomized, prospective study. SETTING: University teaching hospital. PARTICIPANTS: Patients scheduled for elective coronary artery bypass surgery. INTERVENTIONS: All patients were given 50 micrograms/kg of midazolam intramuscularly in their rooms. Group I received 300 micrograms of OTFC Oralet (Anesta Corp, Salt Lake City, UT) if they weighed less than 70 kg and 400 micrograms of OTFC Oralet if they weighed more than 70 kg. Group II received a placebo Oralet. A radial artery catheter, two internal jugular venous catheters, and a pulmonary artery catheter inserted through one of the internal jugular catheters were placed in each study patient. Fentanyl was administered intravenously as a rescue drug. MEASUREMENTS AND MAIN RESULTS: Ninety percent of midazolam/OTFC patients reported feeling no pain during catheter placement, compared with 50% of midazolam/placebo patients. Fifty percent of the placebo group required fentanyl supplement of 50 micrograms intravenously because of complaints of pain, compared with 10% of the OTFC group. The midazolam/OTFC group scored approximately 20% better than the placebo group in the independent observer score of patient analgesia and the anesthesiologist rating for ease of invasive catheter placement. No myocardial ischemic events were noted in either group as determined by electrocardiogram. All patients found the Oralet mode of delivery very acceptable. CONCLUSIONS: The OTFC Oralet provides effective analgesia and sedation when combined with midazolam for invasive catheter placement in adult cardiac surgery patients. The OTFC Oralet with its gradual onset lessens the possibility of overmedicating with fentanyl, and it offers a very acceptable mode of delivery for a preemptive analgesic.

Severe pulmonary hypertension in liver transplant candidates.

Advanced liver disease with portal hypertension may be associated with pulmonary hypertension. A review of 1,205 consecutive liver transplant patients was made to assess the incidence and severity of pulmonary hypertension in patients with end-stage liver disease. Postoperative data were reviewed to determine if outcome was influenced and, in patients with severe pulmonary hypertension, whether pulmonary hypertension was reversed after transplantation. The hemodynamic data of 5 patients who were found to have severe pulmonary hypertension before transplantation and did not receive transplants were also reviewed. The incidence of pulmonary hypertension in the patients who received transplants was 8.5% (n = 102; mean pulmonary artery pressure, > 25 mmHg). The incidence of mild pulmonary hypertension was 6.72% (n = 81; systolic pulmonary artery pressure, 30 to 44 mmHg); that of moderate pulmonary hypertension was 1.16% (n = 14; systolic pulmonary artery pressure, 45 to 59 mmHg); and that of severe pulmonary hypertension was 0.58% (n = 7; systolic pulmonary artery pressure, > 60 mmHg). Mild and moderate pulmonary hypertension did not influence the outcome of the procedure. Severe pulmonary hypertension was associated with mortality rates of 42% at 9 months posttransplantation and 71% at 36 months posttransplantation. Only 2 of 7 patients with severe pulmonary hypertension have survived liver transplantation with a good quality of life. The remaining 5 patients continued to deteriorate with progressive right heart failure with no evidence of amelioration of the pulmonary hypertension. This experience supports the view that in most patients who have severe pulmonary hypertension associated with advanced liver disease, it is caused by fixed pathological changes in the pulmonary vasculature, is not reversible with liver transplantation, and is associated with a very high perioperative mortality rate.

Continuous small-dose tranexamic acid reduces fibrinolysis but not transfusion requirements during orthotopic liver transplantation.

Tranexamic acid (TA) is a synthetic drug that inhibits fibrinolysis. It has been administered to decrease the use of blood products during cardiac surgery and orthotopic liver transplantation when infused in larger doses. A small-dose infusion of aprotinin causes a reduction in fibrinolysis and blood product requirement during orthotopic liver transplantation without apparent risk of intravascular thrombosis. This prospective study was designed to investigate whether a small-dose infusion of TA would be equally effective in reducing fibrinolysis and blood product transfusions during orthotopic liver transplantation. A double-blind, controlled study was undertaken to compare the efficacy of a small-dose TA infusion with that of a placebo. Thirty-two consecutive patients were randomized either to the TA group (n = 16), which received an intravenous infusion of 2 mg x kg(-1) x h(-1), or to the control group (n = 16), which received an identical volume of normal saline. Coagulation values were measured, a field rating was made by the surgeon, and a thromboelastogram was produced at four predetermined intervals throughout the case-before TA infusion was started, after portal vein ligation, 10 min after reperfusion, and at the end of surgery. Intraoperative transfusion requirements were recorded during the procedure and for the first 24 h postoperatively. A record was kept of any intraoperative epsilon-aminocaproic acid administered for uncontrolled fibrinolysis. The thromboelastogram clot lysis index was significant for lysis in the control group during both the anhepatic and the neohepatic phases (P < 0.01 and P < 0.05, respectively) when compared with the TA group. Fibrin degradation products were significantly increased (>20 microg/mL) in the control group at reperfusion (P < 0.03) and at the end of surgery (P < 0.01). D-dimers were also significantly increased (>1 mg/L) in the control group at the end of surgery (P < 0.04). Nine of the 16 control patients versus 3 of the 16 TA patients required epsilon-aminocaproic acid rescue for fibrinolysis. There were no other significant differences between groups. Transfusion requirements during surgery and for the first 24 h postoperatively did not differ significantly between the two groups. We conclude that the use of small-dose TA reduces fibrinolysis but not transfusion requirements during orthotopic liver transplantation.

Pharmacokinetics of rocuronium during the three stages of liver transplantation.

BACKGROUND: Little is known about the influence of liver transplantation on the pharmacokinetics of most anesthetic drugs. The authors determined the pharmacokinetics of rocuronium during liver transplantation and examined whether variability in pharmacokinetics could explain variability in recovery of neuromuscular function. METHODS: Twenty patients undergoing liver transplantation were given rocuronium, 600 microg/kg, after induction of anesthesia and again after perfusion of the transplanted liver. Plasma was sampled to determine rocuronium concentrations. Pharmacokinetic models were fit to rocuronium concentrations versus time data using a mixed-effects population approach. Various models permitted changes in clearance (Cl) or central compartment volume to account for changes in hepatic function and circulatory status during the paleohepatic, anhepatic, and neohepatic periods. Time to initial recovery of four twitches of the orbicularis oculi was determined. RESULTS: During the paleohepatic and anhepatic periods, the typical value of Cl was 2.47 ml x kg(-1) x min(-1) and was not influenced by the magnitude of preexisting liver disease (as evidenced by prothrombin time, bilirubin, serum albumin, alanine transaminase [ALT], and aspartate transaminase [AST]). During the neohepatic period, the typical value of Cl varied as a function of the duration of warm ischemia of the hepatic allograft and was 2.72 ml x kg(-1) x min(-1) for a patient with an average 60-min period of warm ischemia; time to neuromuscular recovery varied as a function of Cl. CONCLUSIONS: Despite prolonged hypothermic ischemia, the newly transplanted liver eliminates rocuronium as well as the diseased native liver (and comparably with historical control values). However, some patients had decreased rocuronium Cl during the neohepatic period, apparently a result of prolonged graft warm ischemia. The authors' finding of preservation of hepatic drug elimination in the hepatic allograft is consistent with limited data for other drugs evaluated during anesthesia.

Duration of rocuronium-induced neuromuscular block during liver transplantation: a predictor of primary allograft function.

The prolongation of vecuronium-induced neuromuscular block has been reported as a predictor of hepatic allograft dysfunction. This study investigates the duration of action of rocuronium, which also relies on hepatic clearance, to examine whether it also is prolonged with allograft dysfunction. Fifty-seven patients undergoing orthotopic liver transplant were given rocuronium (0.6 mg/kg) prior to allograft placement and the recovery of contraction of the orbicularis oculi muscle to a 2-Hz train-of-four stimulus was recorded. Fifteen minutes after reperfusion of the allograft, rocuronium (0.6 mg/kg) was administered and the time to recovery of muscle contraction to a train-of-four stimulus (train-of-four time) was again recorded. The patients were divided into two groups according to posttransplant liver function. Group I consisted of 50 patients with immediate normal liver function. Group II contained 7 patients with primary dysfunctional livers. Primary dysfunction was determined by peak serum aspartate aminotransferase and alanine aminotransferase levels > 2000 U/L, and prothrombin time > 16 s. The train-of-four time in Group II was prolonged compared with Group I (P < 0.05). Immediate graft function testing using the recovery time from rocuronium of > 150 min has a positive predictive value of 100% and a negative predictive value of 96%. The sensitivity and specificity is 71% and 100%, respectively. Receiver operating characteristic analysis supports this conclusion.

Nitric oxide does not reverse pulmonary hypertension associated with end-stage liver disease: a preliminary report.

Pulmonary hypertension is a well known, though uncommon complication of end-stage liver disease (ESLD). Patients with severe pulmonary hypertension and ESLD undergoing orthotopic liver transplantation (OLT) may develop right ventricular failure and death. This study investigates the reversibility of pulmonary hypertension by the inhalation of nitric oxide in patients under evaluation for OLT. Ten patients with ESLD who were discovered to have moderate to severe pulmonary hypertension were administered nitric oxide via face mask in concentrations ranging from 0 to 80 ppm. Inhaled nitric oxide is a potent pulmonary vasodilator without apparent systemic effects. Nitric oxide had no demonstrable effect on mean pulmonary artery pressure (PAP) (37 vs. 37 mm Hg), transpulmonary gradient (TPG) (26 vs. 26 mm Hg), or pulmonary vascular resistance (PVR) (295 vs. 288 dynes x sec x cm (-5)). Two patients were discovered to have an elevated pulmonary artery occlusion pressure (PAOP) on baseline readings. The cause of pulmonary hypertension in these two patients was secondary to volume overload as a result of hepato-renal syndrome rather than primary pulmonary arteriolar pathology and was responsive to diuresis or dialysis but not to nitric oxide therapy. In conclusion nitric oxide does not reverse pulmonary hypertension associated with ESLD.

Identification of a major protein kinase C-binding protein and substrate in rat embryo fibroblasts. Decreased expression in transformed cells.

We have used an interaction cloning strategy to isolate cDNAs for sequences that interact with protein kinase C (Chapline, C., Ramsay, K., Klauck, T., and Jaken, S. (1993) J. Biol. Chem. 268,6858-6861). In this paper, we report a novel sequence, clone 72, isolated according to this method. Clone 72 has a 4.8-kilobase pair open reading frame; antibodies to clone 72 recognize a >200-kDa protein in cell and tissue extracts. Clone 72 message and protein are detected in a variety of tissues. Immunoprecipitation studies demonstrate that clone 72 is the major >200-kDa binding protein described previously in REF52 fibroblasts (Hyatt, S. L., Liao, L., Aderem, A., Nairn, A., and Jaken, S. (1994) Cell Growth & Differ. 5, 495-502). Expression of clone 72 message and protein are decreased in progressively transformed REF52 cells. Since clone 72 is both a protein kinase C (PKC)-binding protein and substrate, decreased levels of clone 72 may influence both the subcellular location of endogenous PKCs as well as signaling events associated with clone 72 phosphorylation. Our results emphasize that the role of PKCs in carcinogenesis may involve several factors, including the quantity and location of the PKCs isozymes and their downstream targets.

35H, a sequence isolated as a protein kinase C binding protein, is a novel member of the adducin family.

We recently cloned a partial cDNA (35H) for a protein kinase C (PKC) binding protein from a rat kidney cDNA library and demonstrated that it is a PKC substrate in vitro (Chapline, C., Ramsay, K., Klauck, T., and Jaken, S. (1993) J. Biol. Chem. 268, 6858-6861). Additional library screening and 5' rapid amplification of cDNA ends were used to obtain the complete open reading frame. Amino acid sequence analysis, DNA sequence analysis, and Northern analysis indicate that 35H is a unique cDNA related to alpha-and beta-adducins. Antisera prepared to the 35H bacterial fusion protein recognized two polypeptides of 80 and 90 kDa on immunoblots of kidney homogenates and cultured renal proximal tubule epithelial cell extracts. The 35H-related proteins were similar to alpha- and beta-adducins in that they were preferentially recovered in the Triton X-100-insoluble (cytoskeletal, CSK) fraction of cell extracts and were predominantly localized to cell borders. Phorbol esters stimulated phosphorylation of CSK 35H proteins, thus emphasizing that sequences isolated according to PKC binding activity in vitro are also PKC substrates in vivo. The phosphorylated forms of the 35H proteins were preferentially recovered in the soluble fraction, thus demonstrating that phosphorylation regulates their CSK association and, thereby, their function in regulating cytoskeletal assemblies. We have isolated another PKC binding protein partial cDNA (clone 45) from a rat fibroblast library with substantial homology to alpha-adducin. Antisera raised against this expressed sequence recognized a protein of 120 kDa, the reported size of alpha-adducin, on immunoblots of renal proximal tubule epithelial cell extracts. A 120-kDa protein that cross-reacts with the clone 45 (alpha-adducin) antisera coprecipitated with 35H immunecomplexes, indicating that alpha-adducin associates with 35H proteins in vivo. Taken together, these results indicate that 35H is a new, widely expressed form of adducin capable of forming heterodimers with alpha-adducin. We propose naming this adducin homologue gamma-adducin.