EEA1 links PI(3)K function to Rab5 regulation of endosome fusion

GTPases and lipid kinases regulate membrane traffic along the endocytic pathway by mechanisms that are not completely understood. Fusion between early endosomes requires phosphatidylinositol-3-OH kinase (PI(3)K) activity as well as the small GTPase Rab5. Excess Rab5-GTP complex restores endosome fusion when PI(3)K is inhibited. Here we identify the early-endosomal autoantigen EEA1 which binds the PI(3)K product phosphatidylinositol-3-phosphate, as a new Rab5 effector that is required for endosome fusion. The association of EEA1 with the endosomal membrane requires Rab5-GTP and PI(3)K activity, and excess Rab5-GTP stabilizes the membrane association of EEA1 even when PI(3)K is inhibited. The identification of EEA1 as a direct Rab5 effector provides a molecular link between PI(3)K and Rab5, and its restricted distribution to early endosomes indicates that EEA1 may confer directionality to Rab5-dependent endocytic transport.

Amiodarone and its desethyl metabolite: tissue distribution and morphologic changes during long-term therapy

The pharmacokinetic characteristics of amiodarone suggest extensive tissue deposition. We confirmed this by measuring tissue concentrations of the drug and of its major metabolite, desethylamiodarone, in human tissues. These were obtained at autopsy (n = 9), surgery (n = 7), or biopsy (n = 2) from 18 patients who had been treated with amiodarone for varying periods of time. High concentrations of amiodarone were found in fat (316 mg/kg wet weight in autopsy specimens, 344 mg/kg wet weight in biopsy specimens). Amiodarone and desethylamiodarone concentrations (mg/kg wet weight, autopsy samples) were also high in liver (391 and 2354), lung (198 and 952), adrenal gland (137 and 437), testis (89 and 470), and lymph node (83 and 316). We also found high concentrations of amiodarone (306 mg/kg wet weight) and desethylamiodarone (943 mg/kg wet weight) in abnormally pigmented ("blue") skin from patients with amiodarone-induced skin pigmentation. These values were 10-fold higher than those in unpigmented skin from the same patients. These high concentrations were associated with lysosomal inclusion bodies in dermal macrophages in the pigmented skin. The inclusion bodies were intrinsically electron dense and were shown to contain iodine by energy dispersive x-ray microanalysis. Lysosomal inclusion bodies shown by electron microscopy to be multilamellar were seen in other tissues. These tissues included terminal nerve fibers in pigmented skin, pulmonary macrophages, blood neutrophils, and hepatocytes and Kupffer cells. These characteristic ultrastructural findings occur in both genetic lipidoses and lipidoses induced by other drugs, e.g., perhexiline. We conclude that during therapy with amiodarone, widespread deposition of amiodarone and desethylamiodarone occurs. This leads to ultrastructural changes typical of a lipidosis. These changes are seen clearly in tissues associated with the unwanted effects of amiodarone, e.g., skin, liver and lung.

Barriers to evidence-based practice implementation: results of a qualitative study

This study reports on a qualitative study of barriers to EBP implementation in one state that sought to implement supported employment and integrated dual diagnosis treatment. The study found that the most significant obstacles emanated from the behavior of supervisors, front-line staff and other professionals in the agency. A lack of synergy profoundly impeded implementation.

Direct interaction of EEA1 with Rab5b

The early endosomal autoantigen EEA1 is essential for early endosomal membrane fusion. It binds to endosomes via a C-terminal domain (EEA1-CT). To identify proteins interacting with EEA1-CT, we screened a human brain library in the yeast two-hybrid system. Fourteen clones reacted strongly with EEA1-CT. Sequencing of these clones revealed that they all contained the ORF of the small GTPase, Rab5b. Further two-hybrid analysis suggested that Rab5b also interacts with the N-terminus of EEA1 (EEA1-NT). The interaction of both EEA1-CT and EEA1-NT with Rab5b was confirmed biochemically, and was found to be GTP dependent. Confocal immunofluorescence microscopy indicated that EEA1 colocalizes with Rab5b on early endosomes. Although EEA1-CT and EEA1-NT interacted strongly with wild-type Rab5b in the two-hybrid system, we detected no interaction with wild-type Rab5a, even though GTPase-deficient mutants of both Rab5a and Rab5b interacted equally well with EEA1. This difference could not be explained by differences in intrinsic GTPase activities, as these were found to be very similar. Instead, we speculate that yeast may contain a GTPase-activating protein (GAP) activity that stimulates Rab5a but not Rab5b. In contrast, pig brain cytosol was found to contain a GAP activity that stimulates the GTPase activity of Rab5b in preference to that of Rab5a. These data provide evidence that EEA1 interacts with both Rab5a and Rab5b, and that the GTPase activities of the two proteins are differentially regulated in vivo.

Evidence-based practice implementation strategies: results of a qualitative study

This study reports on the strategies used to implement the evidence-based practices of supported employment and integrated dual diagnosis treatment. Using qualitative research methods, the study uncovered eight strategies that contributed to successful implementation in six sites.

Ischemic Steal Syndrome: A Case Series and Review of Current Management

BACKGROUND

Currently over 5000 patients are receiving hemodialysis in Australia, which is an increase by approximately 7% each year. Distal ischemia secondary to the steal syndrome (ISS) is an uncommon but recognized complication. Several methods are now available to manage this problem including ligation, banding, and distal revascularization with interval ligation (DRIL). The aim of this report is to review the experience of the authors on this complication and its management at Royal Perth Hospital.

METHODS

The Vascular Physiology Laboratory Database was used to identify those patients referred for investigation of ISS. Data were collected retrospectively from these patients' files concerning their demographics, graft particulars, and type of interventional procedure. Patients were then recalled to assess long-term patency and current venous access and for postoperative vascular studies.

RESULTS

Eighteen people were identified with ischemic symptoms. The mean age was 66 (range, 44 to 82). Fourteen (77.8%) were men, and 15 (83.3%) were diabetic. Renal failure was secondary to diabetes in 8 patients, hypertension in 3, and a combination of both in 7 patients. Intervention was via the DRIL procedure in 12, ligation in 5, and banding in 1. One patient underwent angioplasty of the ulnar artery before DRIL. At follow-up (between 1 and 12 months), all DRIL bypass were patents. The 5 ligated patients all improved, and the patient who underwent banding thrombosed their graft.

CONCLUSION

The DRIL procedure should be considered the standard operation to manage ISS in that it manages the ischemia while maintaining the functional fistula. It is, however, still necessary to ligate some fistulae and seek alternative access. There are still no preoperative indicators as to who will suffer ISS.

The Boerhaave syndrome (spontaneous rupture of the oesophagus)

Two cases of spontaneous rupture of the oesophagus are presented. Thoracotomy and surgical closure of the perforations resulted in satisfactory outcome in both instances. It is believed that the second case is the only recorded case in which haematemesis from a bleeding duodenal ulcer was the precipitating factor, and also it is believed that he is the oldest survivor to be reported. The literature, aetiology, and treatment of this interesting disease are discussed.

A preliminary report on the usefulness of monoclonal antibodies to CA 15-3 and MCA in the detection of micrometastases in axillary lymph nodes draining primary breast carcinoma

The most critical factor affecting survival in patients with breast carcinoma is axillary nodal involvement. Monoclonal antibodies raised against specific human mammary tumour associated antigens may increase detection of micrometastases. This preliminary report examines two of these antigens; CA15-3 antigen and mucin-like carcinoma associated antigen (MCA) in the detection of such deposits. Specimens from 39 stage 1 (node negative) breast carcinoma patients were assessed. Two further 'negative' sections were stained with antisera to CA15-3 and MCA antigens. Micrometastases were detected in 5 patients and in each, MCA and CA15-3 identified the same micrometastases. 3 of these patients had disease progression compared with 3/34 of the remaining patients. The use of monoclonal antibodies to CA15-3 and MCA significantly (P less than 0.05) increases detection rates of micrometastases and this is associated with significantly worse disease-free survival rates (P less than 0.001).

Falls among children in the developing world: a gap in child health burden estimations?

AIM

To estimate the incidence and mortality rates for unintentional fall injuries in children under 5 years of age in three developing regions of the world.

METHODS

This is a systematic review of literature on unintentional childhood fall injuries. A computerized PUBMED search of literature published between 1980 and 2006 was conducted and a manual search of journals was also completed.

RESULTS

Over 140,000 injuries to children under 19 years were reported in 56 studies (21 from Asia, 20 from Africa and 15 from South America); on an average 36% of injuries (52 575) were due to falls. The median incidence is estimated at 137.5 fall injuries per 100,000 children. The incidence of falls specific to the under-5 age group was reported in 16 studies with a median incidence of 40.6 falls per 100,000. The overall average incidence rate for childhood falls is highest in South America at 1315 followed by Asia at 1036 and Africa at 786 per 100,000, respectively. Average mortality rates were highest for Asia at 27 followed by Africa at 13.2 per 100,000, respectively.

CONCLUSION

This review demonstrates that the burden of falls on children has not been well documented, and is most likely under-reported. With the large and growing population of children in developing countries, the public health implications of the observed results are tremendous. Appropriate prevention relies on accurate statistics.

Ambulatory oxygen improves the effectiveness of pulmonary rehabilitation in selected patients with chronic obstructive pulmonary disease

The effect of ambulatory oxygen use during pulmonary rehabilitation (PR) has not yet been clearly established, but many studies have shown benefit from oxygen acutely. Two small studies to date demonstrated no clear benefit when oxygen was used in patients who desaturated on exertion during a PR programme. One study showed the benefit of using oxygen during PR in patients who were normoxic at rest and desaturated to a minimum of 88% on exertion. We conducted a single-blind, randomised controlled trial comparing PR undertaken either with or without ambulatory oxygen, in those with demonstrable benefit from oxygen at baseline. Subjects from three PR services were recruited who, during baseline assessment, desaturated by more than 4% and to less than 90% on exertion, and walked 10% or more further with ambulatory oxygen on endurance shuttle walk test. Patients were randomised to either room air or oxygen via portable cylinder, titrated to optimise pulse oxygen saturation but up to a maximum flow rate of 6 L/min. All patients then completed a twice weekly, 6- to 7-week PR programme. Data were analysed as per protocol. Totally 51 patients completed the study. At the end of PR, both groups improved with PR, with patients in the oxygen group demonstrating a highly statistically significantly greater mean improvement in endurance walking distance than the controls, 490 m (95% confidence interval 228–750; p ≤ 0.001), as well as clinically, although not statistically, significant changes in quality of life. The use of ambulatory oxygen during a 6- to 7-week PR programme greatly improved endurance walking distance in patients who desaturated on exertion with a positive acute response to ambulatory oxygen at baseline.

The endosome fusion regulator early-endosomal autoantigen 1 (EEA1) is a dimer

EEA1, an early-endosomal protein originally identified as an autoantigen, is essential for endocytic membrane fusion. It interacts with early endosomes via binding to the membrane lipid phosphatidylinositol 3-phosphate (PtdIns3P) and the active form of the small GTPase Rab5. Most of the EEA1 sequence contains heptad repeats characteristic of proteins involved in coiled-coil protein-protein interactions. Here we have investigated the ability of EEA1 to self-interact. Crosslinking of cytosolic and recombinant EEA1 resulted in the disappearance of the 180-kDa monomer in SDS/PAGE and the strong appearance of a approximately 350-kDa crosslinked product. Glycerol gradient centrifugation experiments indicated that native EEA1 had the same hydrodynamic properties as the approximately 350-kDa crosslinked complex. Two-hybrid analysis indicated that N- and C-terminal fragments of EEA1 can interact with themselves, but not with each other, suggesting that EEA1 forms parallel coiled-coil dimers. The ability of the C-terminus of EEA1 to dimerize correlates with its ability to bind to Rab5 and early endosomes, whereas its binding to PtdIns3P is independent of dimerization. These data enable us to propose a model for the quaternary structure of EEA1.

Long-term renal risk factors in children with meningomyelocele

We studied renal function and structure in 42 patients with meningomyelocele, 28 treated with intermittent catheterization and 14 with ileal loop diversion. Patients were observed for a minimum of 60 months. Nine of the 28 patients who underwent intermittent catheterization had evidence of unilateral or bilateral reflux, and all patients with ileal loop diversion had free ureteral reflux. Bacteriuria was present in 38% +/- 5% of cultures obtained from patients with catheterization and in 70% +/- 7% of cultures from those with diversion (P less than 0.001). Four (14%) of 28 patients with catheterization had worsening renal function or anatomic appearance by intravenous pyelogram, and required a diversion. Three (28%) of 14 patients with diversion had changes in renal structure or function. Eight of 31 patients from both groups studied with voiding cystourethrography before the onset of therapy had small, noncompliant, trabeculated bladders; all seven patients who had worsening in function or anatomic appearance were from this subset (P less than 0.01). None of the patients with flaccid or distensible bladders demonstrated these changes. Renal disease was unrelated to the level of neurologic function. A small, noncompliant, trabeculated bladder is a risk factor associated with loss of renal function in patients with meningomyelocele.

Production of parathyroid hormone-related protein by a rat parathyroid cell line

Parathyroid hormone-related protein (PTHrP), the peptide associated with humoral hypercalcemia of malignancy, has been identified in fetal and adult parathyroid glands. We here report a sub-clone of a rat parathyroid cell line which secretes a single peptide species corresponding in size to PTHrP(1-84). Biological activity of the secretion product was blocked by a specific antiserum against PTHrP, but not by parathyroid hormone (PTH) antiserum. Secretion of PTHrP by these cells was regulated by extracellular calcium in the physiological range. A single messenger RNA species for PTHrP was identified, though PTH mRNA could not be shown in these cells. Hybrid CAT genes containing 700-1000 bp of 5'-flanking DNA from the human PTH or PTHrP genes were transfected into these cells, and the PTHrP gene was expressed at 10-fold higher levels than the PTH gene. These cells thus provide a valuable model system for investigation expression of PTHrP in a non-transformed cell line.

Soft tissue infection with Absidia corymbifera in a patient with idiopathic aplastic anemia

We describe a case of primary cutaneous mucormycosis (zygomycosis) in a patient with idiopathic aplastic anemia which responded to surgical debridement and therapy with liposomal amphotericin B. The tissue removed at surgery showed dense infiltration with fungal hyphae on histopathological examination. Primary cultures of tissue on solid media were negative, but Absidia corymbifera was isolated from unprocessed tissue placed in brain heart infusion broth.

A six-year study of the Omniscience valve in four Canadian centers

Stimulated by the recent controversy over the Omniscience valve, we conducted a follow-up study on 413 hospital survivors in whom this prosthesis was implanted at four Canadian centers from 1979 to 1985. One hundred forty-seven underwent aortic valve replacement (AVR), 203 had mitral valve replacement (MVR), 10 had tricuspid valve replacement (TVR) and 53 underwent multiple valve replacement (45 AVR + MVR, 5 MVR + TVR, and 3 AVR + MVR + TVR). The mean age was 50.8 +/- 13 years (range, 2 months to 75 years). Follow-up of 96% was achieved for a mean of 2.6 years and a maximum of 6 years with a total of 1,076 patient-years. Complications were defined and graded according to severity. Analyses were performed to yield linearized and actuarial rates for complications. There were 30 late deaths (2.8% per patient-year). At 5 years, the actuarial survival was 89 +/- 3% (AVR, 89 +/- 3% and MVR, 91 +/- 3%). Percentages for freedom from each complication are as follows: endocarditis, 96 +/- 1% (AVR, 96 +/- 2% and MVR, 98 +/- 1%); periprosthetic leak, 99 +/- 0.6% (AVR, 98 +/- 1% and MVR, 99 +/- 0.6%); thrombotic complications, 87 +/- 3% (AVR, 84 +/- 6% and MVR, 90 +/- 3%); valve thrombosis 99.4% (AVR and MVR, 100%); anti-coagulant-related hemorrhage, 94 +/- 2% (AVR, 97 +/- 2% and MVR, 94 +/- 2%); and all valve-related complications, 77 +/- 3% (AVR, 77 +/- 6% and MVR, 79 +/- 4%). Reoperation was required at the rate of 1.2% per patient-year.(ABSTRACT TRUNCATED AT 250 WORDS)

Brevican and phosphacan expression and localization following transient middle cerebral artery occlusion in the rat

The ECM (extracellular matrix) is a complex molecular framework that provides physical support to cells and tissues, while also providing signals for cell growth, migration, differentiation and survival. The ECM of the CNS (central nervous system) is unusual in that it is rich in CSPGs (chondroitin sulfate proteoglycans), hyaluronan and tenascins. The CSPGs are widely expressed throughout the developing and adult CNS and have a role in guiding or limiting neurite outgrowth and cell migration. Alterations in the synthesis or breakdown of the ECM may contribute to disease processes. Here, we examine changes in the brain-specific CSPGs, brevican and phosphacan, following transient middle cerebral artery occlusion, a model of stroke in the rat. We have investigated their expression at various time points as well as their spatial relationship with ADAMTS-4 (adisintegrin and metalloprotease with thrombospondin motifs 4). The co-localization of ADAMTS or its activity may indicate a functional role for this matrix–protease pair in degeneration/regeneration processes that occur in stroke.

Intravenous methylmethacrylate following cemented total hip arthroplasty

Both cemented and noncemented techniques have been used for total hip arthroplasty (THA). Each technique has advantages and disadvantages. Among the disadvantages of cemented THA are several perioperative complications, such as intraoperative cardiac or respiratory failure and hypotension, called "cement implantation syndrome," and extrusion of cement beyond the confines of the medullary canal. Cement extrusion can be the result of overreaming of the femoral canal and cortical perforation. This is a worrisome finding, as the risk of subsequent femoral fracture at the site of perforation is increased. Extruded cement, however, does not always indicate a problem. Extruded cement located within the femoral venous system, intravenous methylmethacrylate, for example, is not associated with long-term complications. While uncommon, it is important to differentiate this finding from the more serious cortical perforation. We report four examples of intravenous methylmethacrylate following THA and describe the imaging features that allow differentiation of this entity from the more significant finding of cortical perforation.

Spontaneous coronary artery dissection in a healthy postmenopausal woman

Spontaneous coronary artery dissection (SCAD) is rare and when it occurs is most commonly seen in young females following childbirth. We report a case of a 55-year-old female who was found dead at her home. She had no history of cardiovascular disease. She smoked approximately 10 cigarettes per day. She complained of mild chest discomfort the night before her death, lasting for 10 minutes, for which no medical attention was sought. She had been seen and appeared well 15 minutes before death. At autopsy, the only abnormality was in the left anterior descending coronary artery, which showed a two cm segment with periluminal blood in the wall of the vessel compressing the lumen. Histologically, a dissection was seen between the media and the external elastic lamina of the affected artery. There was a mixed inflammatory infiltrate including eosinophils and very occasional giant cells. Alcian blue staining was negative. The appearances were those of a localised dissection. The remaining coronary arteries were free of atheroma. SCAD should be suspected in young females in their postpartum period presenting with chest pain since emergency treatment can greatly increase survival.

Colorectal cancer in a small rural hospital

Over a 20-year period, 168 cases of colorectal cancer were treated in a 50-bed rural hospital by 1 surgeon. The majority of the patients were older than 70 years of age. The stage of disease was comparatively advanced, with 71% of the patients having nodal or distant metastases, 19% with bowel obstruction, and 8% with perforation. The operability and resectability rates were 100% and 96%, respectively. The crude 5-year survival was 50% for the entire series. The 5-year survival after curative operations in which there was no gross residual tumor at the end of the operation was 63%, and the 5-year survival for resection of localized node-negative disease was 81%. The wound infection rate was 2%, and the operative mortality rate was 1% for combined elective and emergency operations. The results of treatment of colorectal cancer in small rural hospitals are infrequently reported, and this series may be compared with the published results from large teaching institutions.

Exacerbation of bronchial asthma following treatment with amiodarone. Demonstration of an antiadrenergic effect in vitro

We describe a patient with bronchial asthma whose respiratory symptoms worsened during treatment and rechallenge with amiodarone. Laboratory studies on cultured pulmonary cells demonstrated an anti-beta-adrenergic effect of amiodarone not due to inhibition of beta-adrenergic receptor binding. Amiodarone should be used with caution in patients with obstructive pulmonary disease.