Biallelic FANCA variants detected in sisters with isolated premature ovarian insufficiency

Premature ovarian insufficiency is a common form of female infertility affecting up to 4% of women and characterised by amenorrhea with elevated gonadotropin before the age of 40. Oocytes require controlled DNA breakage and repair for homologous recombination and the maintenance of oocyte integrity. Biallelic disruption of the DNA damage repair gene, Fanconi anemia complementation group A (FANCA), is a common cause of Fanconi anaemia, a syndrome characterised by bone marrow failure, cancer predisposition, physical anomalies and POI. There is ongoing dispute about the role of heterozygous FANCA variants in POI pathogenesis, with insufficient evidence supporting causation. Here, we have identified biallelic FANCA variants in French sisters presenting with POI, including a novel missense variant of uncertain significance and a likely pathogenic deletion that initially evaded detection. Functional studies indicated no discernible effect on DNA damage sensitivity in patient lymphoblasts. These novel FANCA variants add evidence that heterozygous loss of one allele is insufficient to cause DNA damage sensitivity and POI. We propose that intragenic deletions, that are relatively common in FANCA, may be missed without careful analysis, and could explain the presumed causation of heterozygous variants. Accurate variant curation is critical to optimise patient care and outcomes.

CLPB disaggregase dysfunction impacts the functional integrity of the proteolytic SPY complex

CLPB is a mitochondrial intermembrane space AAA+ domain-containing disaggregase. CLPB mutations are associated with 3-methylglutaconic aciduria and neutropenia; however, the molecular mechanism underscoring disease and the contribution of CLPB substrates to disease pathology remains unknown. Interactions between CLPB and mitochondrial quality control (QC) factors, including PARL and OPA1, have been reported, hinting at dysregulation of organelle QC in disease. Utilizing proteomic and biochemical approaches, we show a stress-specific aggregation phenotype in a CLPB-null environment and define the CLPB substrate profile. We illustrate an interplay between intermembrane space proteins including CLPB, HAX1, HTRA2, and the inner membrane quality control proteins (STOML2, PARL, YME1L1; SPY complex), with CLPB deficiency impeding SPY complex function by virtue of protein aggregation in the intermembrane space. We conclude that there is an interdependency of mitochondrial QC components at the intermembrane space/inner membrane interface, and perturbations to this network may underscore CLPB disease pathology.

Human Tim8a, Tim8b and Tim13 are auxiliary assembly factors of mature Complex IV

Human Tim8a and Tim8b are paralogous intermembrane space proteins of the small TIM chaperone family. Yeast small TIMs function in the trafficking of proteins to the outer and inner mitochondrial membranes. This putative import function for hTim8a and hTim8b has been challenged in human models, but their precise molecular function(s) remains undefined. Likewise, the necessity for human cells to encode two Tim8 proteins and whether any potential redundancy exists is unclear. We demonstrate that hTim8a and hTim8b function in the assembly of cytochrome c oxidase (Complex IV). Using affinity enrichment mass spectrometry, we define the interaction network of hTim8a, hTim8b and hTim13, identifying subunits and assembly factors of the Complex IV COX2 module. hTim8-deficient cells have a COX2 and COX3 module defect and exhibit an accumulation of the Complex IV S2 subcomplex. These data suggest that hTim8a and hTim8b function in assembly of Complex IV via interactions with intermediate-assembly subcomplexes. We propose that hTim8-hTim13 complexes are auxiliary assembly factors involved in the formation of the Complex IV S3 subcomplex during assembly of mature Complex IV.

Structure of the endosomal Commander complex linked to Ritscher-Schinzel syndrome

The Commander complex is required for endosomal recycling of diverse transmembrane cargos and is mutated in Ritscher-Schinzel syndrome. It comprises two sub-assemblies: Retriever composed of VPS35L, VPS26C, and VPS29; and the CCC complex which contains twelve subunits: COMMD1-COMMD10 and the coiled-coil domain-containing (CCDC) proteins CCDC22 and CCDC93. Combining X-ray crystallography, electron cryomicroscopy, and in silico predictions, we have assembled a complete structural model of Commander. Retriever is distantly related to the endosomal Retromer complex but has unique features preventing the shared VPS29 subunit from interacting with Retromer-associated factors. The COMMD proteins form a distinctive hetero-decameric ring stabilized by extensive interactions with CCDC22 and CCDC93. These adopt a coiled-coil structure that connects the CCC and Retriever assemblies and recruits a 16th subunit, DENND10, to form the complete Commander complex. The structure allows mapping of disease-causing mutations and reveals the molecular features required for the function of this evolutionarily conserved trafficking machinery.

Neutrophil Recruitment in Pneumococcal Pneumonia

Streptococcus pneumoniae (Spn) is the primary agent of community-acquired pneumonia. Neutrophils are innate immune cells that are essential for bacterial clearance during pneumococcal pneumonia but can also do harm to host tissue. Neutrophil migration in pneumococcal pneumonia is therefore a major determinant of host disease outcomes. During Spn infection, detection of the bacterium leads to an increase in proinflammatory signals and subsequent expression of integrins and ligands on both the neutrophil as well as endothelial and epithelial cells. These integrins and ligands mediate the tethering and migration of the neutrophil from the bloodstream to the site of infection. A gradient of host-derived and bacterial-derived chemoattractants contribute to targeted movement of neutrophils. During pneumococcal pneumonia, neutrophils are rapidly recruited to the pulmonary space, but studies show that some of the canonical neutrophil migratory machinery is dispensable. Investigation of neutrophil migration is necessary for us to understand the dynamics of pneumococcal infection. Here, we summarize what is known about the pathways that lead to migration of the neutrophil from the capillaries to the lung during pneumococcal infection.

Sideroflexin 4 is a complex I assembly factor that interacts with the MCIA complex and is required for the assembly of the ND2 module

SignificanceMitochondria are double-membraned eukaryotic organelles that house the proteins required for generation of ATP, the energy currency of cells. ATP generation within mitochondria is performed by five multisubunit complexes (complexes I to V), the assembly of which is an intricate process. Mutations in subunits of these complexes, or the suite of proteins that help them assemble, lead to a severe multisystem condition called mitochondrial disease. We show that SFXN4, a protein that causes mitochondrial disease when mutated, assists with the assembly of complex I. This finding explains why mutations in SFXN4 cause mitochondrial disease and is surprising because SFXN4 belongs to a family of amino acid transporter proteins, suggesting that it has undergone a dramatic shift in function through evolution.

Super-resolution microscopy reveals the arrangement of inner membrane protein complexes in mammalian mitochondria

The mitochondrial inner membrane is a protein-rich environment containing large multimeric complexes, including complexes of the mitochondrial electron transport chain, mitochondrial translocases and quality control machineries. Although the inner membrane is highly proteinaceous, with 40-60% of all mitochondrial proteins localised to this compartment, little is known about the spatial distribution and organisation of complexes in this environment. We set out to survey the arrangement of inner membrane complexes using stochastic optical reconstruction microscopy (STORM). We reveal that subunits of the TIM23 complex, TIM23 and TIM44 (also known as TIMM23 and TIMM44, respectively), and the complex IV subunit COXIV, form organised clusters and show properties distinct from the outer membrane protein TOM20 (also known as TOMM20). Density based cluster analysis indicated a bimodal distribution of TIM44 that is distinct from TIM23, suggesting distinct TIM23 subcomplexes. COXIV is arranged in larger clusters that are disrupted upon disruption of complex IV assembly. Thus, STORM super-resolution microscopy is a powerful tool for examining the nanoscale distribution of mitochondrial inner membrane complexes, providing a 'visual' approach for obtaining pivotal information on how mitochondrial complexes exist in a cellular context.

Mitochondrial protein import dysfunction: mitochondrial disease, neurodegenerative disease and cancer

The majority of proteins localised to mitochondria are encoded by the nuclear genome, with approximately 1500 proteins imported into mammalian mitochondria. Dysfunction in this fundamental cellular process is linked to a variety of pathologies including neuropathies, cardiovascular disorders, myopathies, neurodegenerative diseases and cancer, demonstrating the importance of mitochondrial protein import machinery for cellular function. Correct import of proteins into mitochondria requires the co-ordinated activity of multimeric protein translocation and sorting machineries located in both the outer and inner mitochondrial membranes, directing the imported proteins to the destined mitochondrial compartment. This dynamic process maintains cellular homeostasis, and its dysregulation significantly affects cellular signalling pathways and metabolism. This review summarises current knowledge of the mammalian mitochondrial import machinery and the pathological consequences of mutation of its components. In addition, we will discuss the role of mitochondrial import in cancer, and our current understanding of the role of mitochondrial import in neurodegenerative diseases including Alzheimer's disease, Huntington's disease and Parkinson's disease.

The TIM22 complex mediates the import of sideroflexins and is required for efficient mitochondrial one-carbon metabolism

Acylglycerol kinase (AGK) is a mitochondrial lipid kinase that contributes to protein biogenesis as a subunit of the TIM22 complex at the inner mitochondrial membrane. Mutations in AGK cause Sengers syndrome, an autosomal recessive condition characterized by congenital cataracts, hypertrophic cardiomyopathy, skeletal myopathy, and lactic acidosis. We mapped the proteomic changes in Sengers patient fibroblasts and AGK^KO cell lines to understand the effects of AGK dysfunction on mitochondria. This uncovered down-regulation of a number of proteins at the inner mitochondrial membrane, including many SLC25 carrier family proteins, which are predicted substrates of the complex. We also observed down-regulation of SFXN proteins, which contain five transmembrane domains, and show that they represent a novel class of TIM22 complex substrate. Perturbed biogenesis of SFXN proteins in cells lacking AGK reduces the proliferative capabilities of these cells in the absence of exogenous serine, suggesting that dysregulation of one-carbon metabolism is a molecular feature in the biology of Sengers syndrome.

Proteomic Identification of Coxiella burnetii Effector Proteins Targeted to the Host Cell Mitochondria During Infection

Modulation of the host cell is integral to the survival and replication of microbial pathogens. Several intracellular bacterial pathogens deliver bacterial proteins, termed "effector proteins" into the host cell during infection by sophisticated protein translocation systems, which manipulate cellular processes and functions. The functional contribution of individual effectors is poorly characterized, particularly in intracellular bacterial pathogens with large effector protein repertoires. Technical caveats have limited the capacity to study these proteins during a native infection, with many effector proteins having only been demonstrated to be translocated during over-expression of tagged versions. Here, we developed a novel strategy to examine effector proteins in the context of infection. We coupled a broad, unbiased proteomics-based screen with organelle purification to study the host-pathogen interactions occurring between the host cell mitochondrion and the Gram-negative, Q fever pathogen Coxiella burnetii. We identify four novel mitochondrially-targeted C. burnetii effector proteins, renamed Mitochondrial Coxiella effector protein (Mce) B to E. Examination of the subcellular localization of ectopically expressed proteins confirmed their mitochondrial localization, demonstrating the robustness of our approach. Subsequent biochemical analysis and affinity enrichment proteomics of one of these effector proteins, MceC, revealed the protein localizes to the inner membrane and can interact with components of the mitochondrial quality control machinery. Our study adapts high-sensitivity proteomics to study intracellular host-pathogen interactions, providing a robust strategy to examine the subcellular localization of effector proteins during native infection. This approach could be applied to a range of pathogens and host cell compartments to provide a rich map of effector dynamics throughout infection.

Function of hTim8a in complex IV assembly in neuronal cells provides insight into pathomechanism underlying Mohr-Tranebjærg syndrome

Human Tim8a and Tim8b are members of an intermembrane space chaperone network, known as the small TIM family. Mutations in TIMM8A cause a neurodegenerative disease, Mohr-Tranebjærg syndrome (MTS), which is characterised by sensorineural hearing loss, dystonia and blindness. Nothing is known about the function of hTim8a in neuronal cells or how mutation of this protein leads to a neurodegenerative disease. We show that hTim8a is required for the assembly of Complex IV in neurons, which is mediated through a transient interaction with Complex IV assembly factors, in particular the copper chaperone COX17. Complex IV assembly defects resulting from loss of hTim8a leads to oxidative stress and changes to key apoptotic regulators, including cytochrome c, which primes cells for death. Alleviation of oxidative stress with Vitamin E treatment rescues cells from apoptotic vulnerability. We hypothesise that enhanced sensitivity of neuronal cells to apoptosis is the underlying mechanism of MTS.

The Rare Anaphylaxis-Associated FcγRIIa3 Exhibits Distinct Characteristics From the Canonical FcγRIIa1

FcγRIIa is an activating FcγR, unique to humans and non-human primates. It induces antibody-dependent proinflammatory responses and exists predominantly as FcγRIIa1. A unique splice variant, we designated FcγRIIa3, has been reported to be associated with anaphylactic reactions to intravenous immunoglobulins (IVIg) therapy. We aim to define the functional consequences of this FcγRIIa variant associated with adverse responses to IVIg therapy and evaluate the frequency of associated SNPs. FcγRIIa forms from macaque and human PBMCs were investigated for IgG-subclass specificity, biochemistry, membrane localization, and functional activity. Disease-associated SNPs were analyzed by sequencing genomic DNA from 224 individuals with immunodeficiency or autoimmune disease. FcγRIIa3 was identified in macaque and human PBMC. The FcγRIIa3 is distinguished from the canonical FcγRIIa1 by a unique 19-amino acid cytoplasmic insertion and these two FcγRIIa forms responded distinctly to antibody ligation. Whereas FcγRIIa1 was rapidly internalized, FcγRIIa3 was retained longer at the membrane, inducing greater calcium mobilization and cell degranulation. Four FCGR2A SNPs were identified including the previously reported intronic SNP associated with anaphylaxis, but in only 1 of 224 individuals. The unique cytoplasmic element of FcγRIIa3 delays internalization and is associated with enhanced cellular activation. The frequency of the immunodeficiency-associated SNP varies between disease populations but interestingly occurred at a lower frequency than previously reported. None-the-less enhanced FcγRIIa3 function may promote a proinflammatory environment and predispose to pathological inflammatory responses.

Revised Functional Capacity Index as a predictor of outcome following injury

BACKGROUND

Assessment of functional outcomes in survivors of severe injury is an identified priority for trauma systems. The predictive Functional Capacity Index (pFCI) within the 2008 Abbreviated Injury Scale dictionary (pFCI08) offers a widely available tool for predicting functional outcomes without requiring long-term follow-up. This study aimed to assess the 12-month functional outcome predictions of pFCI08 in a major trauma population, and to test the assumptions made by its developers to ensure population homogeneity.

METHODS

Patients with major trauma from Victoria, Australia, were followed up using routine telephone interviews. Assessment of survivors 12 months after injury included the Glasgow Outcome Scale - Extended (GOS-E). κ scores were used to measure agreement between pFCI08 and assessed GOS-E scores.

RESULTS

Of 20 098 patients with severe injury, 12 417 had both pFCI08 and GOS-E scoring available at 12 months. The quadratic weighted κ score across this population was 0·170; this increased to 0·244 in the subgroup of 1939 patients who met all pFCI assumptions. However, expanding the age range used in this group did not significantly affect κ scores until patients over the age of 70 years were included.

DISCUSSION

The pFCI08 has only a slight agreement with outcomes following major trauma. However, the age limits in the pFCI development assumptions are unnecessarily restrictive. The pFCI08 may be able to contribute to future systems predicting functional outcomes following severe injury, but is likely to explain only a small proportion of the variability in patient outcomes.

Cooperative and independent roles of the Drp1 adaptors Mff, MiD49 and MiD51 in mitochondrial fission

Cytosolic dynamin-related protein 1 (Drp1, also known as DNM1L) is required for both mitochondrial and peroxisomal fission. Drp1-dependent division of these organelles is facilitated by a number of adaptor proteins at mitochondrial and peroxisomal surfaces. To investigate the interplay of these adaptor proteins, we used gene-editing technology to create a suite of cell lines lacking the adaptors MiD49 (also known as MIEF2), MiD51 (also known as MIEF1), Mff and Fis1. Increased mitochondrial connectivity was observed following loss of individual adaptors, and this was further enhanced following the combined loss of MiD51 and Mff. Moreover, loss of adaptors also conferred increased resistance of cells to intrinsic apoptotic stimuli, with MiD49 and MiD51 showing the more prominent role. Using a proximity-based biotin labeling approach, we found close associations between MiD51, Mff and Drp1, but not Fis1. Furthermore, we found that MiD51 can suppress Mff-dependent enhancement of Drp1 GTPase activity. Our data indicates that Mff and MiD51 regulate Drp1 in specific ways to promote mitochondrial fission.

Mitochondrial protein quality control in health and disease

Progressive mitochondrial dysfunction is linked with the onset of many age-related pathologies and neurological disorders. Mitochondrial damage can come in many forms and be induced by a variety of cellular insults. To preserve organelle function during biogenesis or times of stress, multiple surveillance systems work to ensure the persistence of a functional mitochondrial network. This review provides an overview of these processes, which collectively contribute to the maintenance of a healthy mitochondrial population, which is critical for cell physiology and survival.

The full spectrum of handlebar injuries in children: a decade of experience

BACKGROUND

Traumatic paediatric handlebar injury (HBI) is known to occur with different vehicles, affect different body regions, and have substantial associated morbidity. However, previous handlebar injury research has focused on the specific combination of abdominal injury and bicycle riding. Our aim was to fully describe the epidemiology and resultant spectrum of injuries caused by a HBI.

METHODS

Retrospective data analysis of all paediatric patients (<18 years) in a prospectively identified trauma registry over a 10-year period. Primary outcome was the HBI, its location and management. The effects of patient age, vehicle type, the impact region, and Injury Severity Score (ISS) were also evaluated. HBI patients were compared against a cohort injured while riding similar vehicles, but not having sustained a HBI.

RESULTS

1990 patients were admitted with a handlebar-equipped vehicle trauma; 236 (11.9%) having sustained a HBI. HBI patients were twice as likely to be aged between 6 and 14 years old compared with non-HBI patients (OR 2.2; 95% CI 1.5-3.2). 88.6% of the HBI patients sustained an isolated injury, and 45.3% had non-abdominal handlebar impact. There were no significant differences in median ISS (p=0.4) or need for operative intervention (OR 1.1; 95% CI 0.9-1.5) between HBI and non-HBI patients. HBI patients had a significantly longer LOS (1.8 days vs. 1.2 days; p=0.001), and more frequently required a major operation (OR 3.4; 95% CI 2.2-5.4). The majority of splenic, renal and hepatic injuries were managed conservatively.

CONCLUSIONS

Although the majority of paediatric HBI is associated with both intra-abdominal injury and bicycle riding, it produces a spectrum of potentially serious injuries and patients are more likely to undergo major surgery. Therefore these patients should always be treated with a high degree of suspicion.

Structural and functional analysis of MiD51, a dynamin receptor required for mitochondrial fission

Structure–function analyses driven by a crystal structure of the cytosolic domain of the Drp1 receptor MiD51 reveals a nucleotidyltransferase fold and nucleotide binding activity that is independent of its Drp1 binding activity.

Mitochondrial fission is important for organelle transport, inheritance, and turnover, and alterations in fission are seen in neurological disease. In mammals, mitochondrial fission is executed by dynamin-related protein 1 (Drp1), a cytosolic guanosine triphosphatase that polymerizes and constricts the organelle. Recruitment of Drp1 to mitochondria involves receptors including Mff, MiD49, and MiD51. MiD49/51 form foci at mitochondrial constriction sites and coassemble with Drp1 to drive fission. Here, we solved the crystal structure of the cytosolic domain of human MiD51, which adopts a nucleotidyltransferase fold. Although MiD51 lacks catalytic residues for transferase activity, it specifically binds guanosine diphosphate and adenosine diphosphate. MiD51 mutants unable to bind nucleotides were still able to recruit Drp1. Disruption of an additional region in MiD51 that is not part of the nucleotidyltransferase fold blocked Drp1 recruitment and assembly of MiD51 into foci. MiD51 foci are also dependent on the presence of Drp1, and after scission they are distributed to daughter organelles, supporting the involvement of MiD51 in the fission apparatus.

Adaptor proteins MiD49 and MiD51 can act independently of Mff and Fis1 in Drp1 recruitment and are specific for mitochondrial fission

Drp1 (dynamin-related protein 1) is recruited to both mitochondrial and peroxisomal membranes to execute fission. Fis1 and Mff are Drp1 receptor/effector proteins of mitochondria and peroxisomes. Recently, MiD49 and MiD51 were also shown to recruit Drp1 to the mitochondrial surface; however, different reports have ascribed opposing roles in fission and fusion. Here, we show that MiD49 or MiD51 overexpression blocked fission by acting in a dominant-negative manner by sequestering Drp1 specifically at mitochondria, causing unopposed fusion events at mitochondria along with elongation of peroxisomes. Mitochondrial elongation caused by MiD49/51 overexpression required the action of fusion mediators mitofusins 1 and 2. Furthermore, at low level overexpression when MiD49 and MiD51 form discrete foci at mitochondria, mitochondrial fission events still occurred. Unlike Fis1 and Mff, MiD49 and MiD51 were not targeted to the peroxisomal surface, suggesting that they specifically act to facilitate Drp1-directed fission at mitochondria. Moreover, when MiD49 or MiD51 was targeted to the surface of peroxisomes or lysosomes, Drp1 was specifically recruited to these organelles. Moreover, the Drp1 recruitment activity of MiD49/51 appeared stronger than that of Mff or Fis1. We conclude that MiD49 and MiD51 can act independently of Mff and Fis1 in Drp1 recruitment and suggest that they provide specificity to the division of mitochondria.

Recent advances into the understanding of mitochondrial fission

Mitochondria exist as a highly dynamic tubular network, and their morphology is governed by the delicate balance between frequent fusion and fission events, as well as by interactions with the cytoskeleton. Alterations in mitochondrial morphology are associated with changes in metabolism, cell development and cell death, whilst several human pathologies have been associated with perturbations in the cellular machinery that coordinate these processes. Mitochondrial fission also contributes to ensuring the proper distribution of mitochondria in response to the energetic requirements of the cell. The master mediator of fission is Dynamin related protein 1 (Drp1), which polymerises and constricts mitochondria to facilitate organelle division. The activity of Drp1 at the mitochondrial outer membrane is regulated through post-translational modifications and interactions with mitochondrial receptor and accessory proteins. This review will concentrate on recent advances made in delineating the mechanism of mitochondrial fission, and will highlight the importance of mitochondrial fission in health and disease. This article is part of a Special Issue entitled: Mitochondrial dynamics and physiology.

The regulation of mitochondrial morphology: intricate mechanisms and dynamic machinery

Mitochondria typically form a reticular network radiating from the nucleus, creating an interconnected system that supplies the cell with essential energy and metabolites. These mitochondrial networks are regulated through the complex coordination of fission, fusion and distribution events. While a number of key mitochondrial morphology proteins have been identified, the precise mechanisms which govern their activity remain elusive. Moreover, post translational modifications including ubiquitination, phosphorylation and sumoylation of the core machinery are thought to regulate both fusion and division of the network. These proteins can undergo several different modifications depending on cellular signals, environment and energetic demands of the cell. Proteins involved in mitochondrial morphology may also have dual roles in both dynamics and apoptosis, with regulation of these proteins under tight control of the cell to ensure correct function. The absolute reliance of the cell on a functional mitochondrial network is highlighted in neurons, which are particularly vulnerable to any changes in organelle dynamics due to their unique biochemical requirements. Recent evidence suggests that defects in the shape or distribution of mitochondria correlate with the progression of neurodegenerative diseases such as Alzheimer's, Huntington's and Parkinson's disease. This review focuses on our current understanding of the mitochondrial morphology machinery in cell homeostasis, apoptosis and neurodegeneration, and the post translational modifications that regulate these processes.

MiD49 and MiD51, new components of the mitochondrial fission machinery

Mitochondria form intricate networks through fission and fusion events. Here, we identify mitochondrial dynamics proteins of 49 and 51 kDa (MiD49 and MiD51, respectively) anchored in the mitochondrial outer membrane. MiD49/51 form foci and rings around mitochondria similar to the fission mediator dynamin-related protein 1 (Drp1). MiD49/51 directly recruit Drp1 to the mitochondrial surface, whereas their knockdown reduces Drp1 association, leading to unopposed fusion. Overexpression of MiD49/51 seems to sequester Drp1 from functioning at mitochondria and cause fused tubules to associate with actin. Thus, MiD49/51 are new mediators of mitochondrial division affecting Drp1 action at mitochondria.

Blunt abdominal trauma in children: how predictive is ALT for liver injury?

BACKGROUND

The liver is the second most commonly injured intra-abdominal organ in children. CT scanning is currently regarded as the "gold standard" in screening for intra-abdominal injury following blunt trauma. However, the risks associated with performing CT in children are not insignificant and, in addition, CT is not always readily available. This study investigates the utility of alanine aminotransferase (ALT) in screening for liver injury in paediatric trauma.

METHODS

Two groups of patients were compiled from a prospectively identified trauma registry-one with liver injuries and another with intra-abdominal injuries other than to the liver. Inclusion in the study required that an initial ALT level had been obtained after injury. Where CT had been performed, a paediatric radiologist blind to the ALT results graded the severity of the liver injuries. The study groups were compared and a receiver operating characteristic (ROC) curve generated to derive the optimum ALT threshold to identify liver injury.

RESULTS

51 patients with liver injury and 65 with other intra-abdominal injuries were identified. An ALT level of > or =104 IU/l gave a sensitivity of 96% and a specificity of 80%. When liver injuries were stratified to identify only clinically significant liver injuries (grades III, IV and V), this ALT threshold identified 100% of patients with 70% specificity.

CONCLUSIONS

In this sample, ALT appears to be a useful predictor for the presence or absence of liver injury. In haemodynamically stable children with clinical suspicion of isolated liver injury, identification of a normal ALT level (<104 IU/l) may reduce the need for unnecessary transportation for CT scanning with subsequent radiation exposure.

Structural and functional requirements for activity of the Tim9-Tim10 complex in mitochondrial protein import

The Tim9-Tim10 complex plays an essential role in mitochondrial protein import by chaperoning select hydrophobic precursor proteins across the intermembrane space. How the complex interacts with precursors is not clear, although it has been proposed that Tim10 acts in substrate recognition, whereas Tim9 acts in complex stabilization. In this study, we report the structure of the yeast Tim9-Tim10 hexameric assembly determined to 2.5 A and have performed mutational analysis in yeast to evaluate the specific roles of Tim9 and Tim10. Like the human counterparts, each Tim9 and Tim10 subunit contains a central loop flanked by disulfide bonds that separate two extended N- and C-terminal tentacle-like helices. Buried salt-bridges between highly conserved lysine and glutamate residues connect alternating subunits. Mutation of these residues destabilizes the complex, causes defective import of precursor substrates, and results in yeast growth defects. Truncation analysis revealed that in the absence of the N-terminal region of Tim9, the hexameric complex is no longer able to efficiently trap incoming substrates even though contacts with Tim10 are still made. We conclude that Tim9 plays an important functional role that includes facilitating the initial steps in translocating precursor substrates into the intermembrane space.

Dilation of the subarachnoid spaces surrounding the cranial nerves with petrous apex cephaloceles in Usher syndrome

Limited studies of brain MR imaging findings in Usher syndrome have reported atrophy with enlarged subarachnoid spaces. However, the specific appearance of the subarachnoid spaces surrounding the cranial nerves has not yet been described. Herein we describe the skull base MR imaging findings in an adult with Usher syndrome. Multiple cranial nerve exits were enlarged to the point of causing cephaloceles with bony remodeling. A combination of uncommon findings in this rare disorder raises the question of an etiologic association.

Detection of aneurysms by 64-section multidetector CT angiography in patients acutely suspected of having an intracranial aneurysm and comparison with digital subtraction and 3D rotational angiography

BACKGROUND AND PURPOSE

Four-section multisection CT angiography (MSCTA) accurately detects aneurysms at or more than 4 mm but is less accurate for those less than 4 mm. Our purpose was to determine the accuracy of 64-section MSCTA (64MSCTA) in aneurysm detection versus combined digital subtraction angiography (DSA) and 3D rotational angiography (3DRA).

MATERIALS AND METHODS

In a retrospective review of patients studied because of acute symptoms suspicious for arising from an intracranial aneurysm, 63 subjects were included who had undergone CT angiography (CTA). Of these, 36 underwent catheter DSA; all but 4 were also studied with 3DRA. The most common indication was subarachnoid hemorrhage (SAH; n = 43). Two neuroradiologists independently reviewed each CTA, DSA, and 3DRA.

RESULTS

A total of 41 aneurysms were found in 28 patients. The mean size was 6.09 mm on DSA/3DRA and 5.98 mm on 64MSCTA. kappa was excellent (0.97) between the aneurysm size on 64MSCTA and DSA/3DRA. Ultimately, 37 aneurysms were detected by DSA/3DRA in 25 of the 36 patients who underwent conventional angiography. The reviewers noted four 1- to 1.5-mm sessile outpouchings only on 3DRA; none were considered a source of SAH. One 64MSCTA was false positive, whereas one 2-mm aneurysm was missed by CTA. The sensitivity of CTA for aneurysms less than 4 mm was 92.3%, whereas it was 100% for those 4-10 mm and more than 10 mm, excluding the indeterminate, sessile lesions.

CONCLUSIONS

In comparison with the available literature, 64MSCTA may have improved the detection of less than 4-mm aneurysms compared with 4- or 16-section CTA. However, the combination of DSA with 3DRA is currently the most sensitive technique to detect untreated aneurysms and should be considered in suspicious cases of SAH where the aneurysm is not depicted by 64MSCTA, because 64MSCTA may occasionally miss aneurysms less than 3-4 mm size.

Cost-effectiveness analysis of an intranasal influenza vaccine for the prevention of influenza in healthy children

OBJECTIVE

Intranasal influenza vaccine has proven clinical efficacy and may be better tolerated by young children and their families than an injectable vaccine. This study determined the potential cost-effectiveness (CE) of an intranasal influenza vaccine among healthy children.

METHODS

We conducted a CE analysis of data collected between 1996 and 1998 during a prospective 2-year efficacy trial of intranasal influenza vaccine, supplemented with data from the literature. The CE analysis included both direct and indirect costs. We enrolled 1602 healthy children aged 15 to 71 months in year 1, 1358 of whom were enrolled in year 2. One or 2 doses of intranasal influenza vaccine or placebo were administered to measure the cost per febrile influenza-like illness (ILI) day avoided.

RESULTS

During the 2-year study period, vaccinated children had an average of 1.2 fewer ILI fever days/child than unvaccinated children. In an individual-based vaccine delivery scenario with vaccine given twice in the first year and once each year thereafter at an assumed base case total cost of $20 for the vaccine and its administration (ie, per dose), CE was approximately $30/febrile ILI day avoided. CE ranged from $10 to $69/febrile ILI day avoided at $10 to $40/dose, respectively. In a group-based delivery scenario, vaccination was cost saving compared with placebo and remained so if vaccine cost was <$28 (the break-even price per dose). In the individual-based scenario, vaccination was cost saving if vaccine cost was <$5. In this scenario, nearly half of lost productivity in the vaccine group was attributable to vaccine visits, which overshadowed the relatively modest savings in ILI-associated costs averted.

CONCLUSIONS

Routine use of intranasal influenza vaccine among healthy children may be cost-effective and may be maximized by using group-based vaccination approaches. cost-effectiveness, influenza, vaccine, children.

Patient preferences and utilities for 'off-time' outcomes in the treatment of Parkinson's disease

The purpose of this study was to derive patient preferences and utilities for outcomes associated with treatment of motor fluctuations, or 'off-time', for patients with Parkinson's disease (PD). Visual analog scale (VAS) and standard gamble (SG) approaches were used with 60 patients to determine patient preferences and utilities for 10 health state descriptions. Health state descriptions were categorized according to two factors: disease severity, and proportion of the day with 'off-time'. There were two representative levels of disease severity, based on Hoehn and Yahr stages 1.5 and 2.5: unilateral disease with no postural instability, and bilateral disease with some postural instability. These severity levels were combined with five levels of 'off-time' per day ranging from none to > 75% of the day. Patients' mean preference or utility for their own current health ranged from 0.65 +/- 0.20 (VAS) to 0.74 +/- 0.22 (SG). Patients assigned the lowest mean values to the health state description for Hoehn and Yahr stage 2.5 with 'off-time' for > 75% of the day (VAS: 0.17 +/- 0.17; SG: 0.49 +/- 0.27). The highest mean values were assigned to Hoehn and Yahr stage 1.5 with no 'off-time' (VAS: 0.83 +/- 0.17; SG: 0.85 +/- 0.18). The results of this study indicated patients with PD would likely seek treatment that would minimize the amount of 'off-time' experienced per day, and that patients were relatively risk averse.

Economic assessment of the community-acquired pneumonia intervention trial employing levofloxacin

OBJECTIVE

The purpose of this study was to assess use of a critical pathway designed to manage community-acquired pneumonia more efficiently than its management with conventional therapy.

METHODS

Economic outcomes were assessed in conjunction with a cluster-design, randomized, controlled trial. Nineteen participating Canadian hospitals were randomized to implement the critical pathway (n = 9) or conventional therapy (n = 10). The critical pathway included a clinical prediction rule to guide the admission decision, treatment with levofloxacin, and practice guidelines. Patient data on medical resource use, lost productivity, and quality of life were collected prospectively for > or =6 weeks after treatment. Costs were calculated from the government, health care system, and societal perspectives, with imputation of missing outpatient costs and the costs of lost productivity when necessary. Bootstrapping was used to identify 95% CIs for the total cost per patient.

RESULTS

The analysis included all eligible patients in the critical pathway (n = 716) and conventional therapy (n = 1027) arms. There were fewer hospital admissions in the critical pathway arm than in the conventional therapy arm, both overall (46.5% vs 62.2%; P = 0.01) and in low-risk patients (33.2% vs 46.8%; P < 0.001). Compared with conventional therapy, hospitals in the critical pathway arm had 1.6 fewer bed days per patient managed (P = 0.05) and used fewer inpatient medical resources. The 2 study arms had similar outpatient, readmission, and lost-productivity costs, and similar quality-of-life outcomes. The critical pathway produced cost savings from all 3 perspectives that ranged from $457 to $994 per patient.

CONCLUSIONS

The critical pathway employing levofloxacin resulted in cost savings compared with conventional therapy and did not compromise health outcomes.

A prospective study of the cost-utility of the multichannel cochlear implant

CONTEXT

Prior clinical studies have indicated that cochlear implantation provides benefits to individuals with advanced sensorineural hearing loss who are unable to gain effective speech recognition with hearing aids.

OBJECTIVE

To determine the cost per quality-adjusted life-year (QALY) for adults receiving multichannel cochlear implants.

DESIGN

Prospective 12-month multicenter study using preference-based quality-of-life measures and total cost determinations, comparing profoundly hearing-impaired adult subjects with and without cochlear implants.

SETTING

Hospital-based and patient-resource clinics.

PATIENTS

Severely to profoundly hearing-impaired adult recipients of a cochlear implant and adults eligible for the device who had not yet received it.

MAIN OUTCOME MEASURE

Clinical assessment of implant participants included medical and audiologic (speech understanding) data at the time of enrollment, 6 months, and 12 months. All participants' health-utility was assessed at the time of enrollment, 6 months, and 12 months using the Health Utility Index. One-year medical resource utilization and cost data included bills related to implants, patient diaries, charge estimates from clinical sites, and published literature. A decision model was developed to determine cost per QALY.

RESULTS

Of the 84 enrolled adults, 62 (75%) completed the study. Mean health-utility scores at the time of enrollment were identical between groups. The marginal 12-month health-utility gain for implant recipients was 0.20; 90% of this improvement was achieved within 6 months. For patients with a mean 22-year life expectancy, the marginal cost per QALY was $14,670.

CONCLUSIONS

Overall, multichannel cochlear implants significantly improved recipients' performance on measures of speech understanding and ratings of health-utility within 6 months of implantation. The multichannel cochlear implant yielded a very favorable cost per QALY.

The relation of patient satisfaction with treatment of otitis externa to clinical outcomes: development of an instrument

This survey was undertaken to develop a short, comprehensive measure of patient satisfaction with pharmacologic treatment for otitis externa and to assess the relationships between satisfaction, disease symptoms, and medication side effects. Otitis externa was diagnosed in 41 patients recruited from 6 sites; 34 patients completed and returned the study instruments and were included in the study. Patients or their caregivers administered polymyxin/neomycin/hydrocortisone ear drops prescribed by a physician and completed a daily diary for 10 days and a satisfaction questionnaire at the end of the treatment period. The main outcome measures were the subscale scores for patient satisfaction and their relation to medication side effects, symptoms of ear infection, activity limitations, pain, and adherence to prescription regimens. The questionnaire and its subscales demonstrated good psychometric properties (ie, reliability coefficients >0.75, except for 1 subscale). Overall satisfaction was found to be significantly correlated with relief of symptoms, ability to return to normal activities, ease of administration, and medication side effects. Satisfaction subscale scores were correlated with patient-reported severity of medication side effects and disease symptoms. More than half the patients took drops for more than the prescribed number of days, and one third took more than the prescribed number of drops per administration (ie, overadherence). The relation between satisfaction and adherence was weak, perhaps due to the high rates of overadherence. Our results demonstrate that patient satisfaction with otic medication can be assessed across various aspects of satisfaction and that it is correlated with reported disease symptoms and medication side effects. This type of multifaceted assessment may help physicians select between medications with different side-effect profiles and administration schedules. Larger studies are needed to evaluate the relationship between satisfaction with an otic medication and adherence to a medication regimen.

Treatment patterns for otitis externa

BACKGROUND

Although otitis externa is a common and painful infection of the outer ear canal, there is little specific information available regarding current treatment patterns in the United States. We wanted to examine treatment patterns for otitis externa.

METHODS

Data were analyzed from the 1993 National Ambulatory Medical Care Survey (NAMCS) and the 1993 National Hospital Ambulatory Medical Care Survey (NHAMCS) for adults and children treated for otitis externa. Data analyses included the reasons for physician visits, concomitant diagnoses, types of physicians seen, sources of payment, medical procedures administered, drugs prescribed, and patient disposition following a physician visit.

RESULTS

Study results suggested that treatment patterns differ substantially for adults and children, as well as by physician specialty. Although otitis externa is frequently painful, few cases are classified as severe, and the data indicated that less than 20 percent of patients have concomitant diagnoses treatable by medication. Nevertheless, 40 percent of patients received both topical and systemic medication, and many of the oral antibiotics prescribed are not active against Staphylococcus aureus or Pseudomonas aeruginosa, the most common bacterial pathogens in otitis externa.

CONCLUSIONS

Appropriate treatment of localized otitis externa with topical antibiotics should eliminate the need for systemic medications. Addition of systemic medications can unnecessarily increase treatment costs and the likelihood of side effects, and could reduce the likelihood of patient compliance.

A pharmacoeconomic analysis of rimexolone for the treatment of ophthalmic inflammatory conditions

Topical steroids are the standard first-line therapy for treating ophthalmic inflammatory conditions. However, potent ophthalmic steroids can lead to an elevation of intraocular pressure (IOP), which can result in greater medical resource utilization and increased costs. We have developed a decision analysis model from a societal perspective to evaluate the costs and consequences of the treatment of ophthalmic inflammatory conditions with two potent topical steroids: prednisolone and rimexolone. Data for the model are based on information from clinical trials, national data-bases, published literature, and responses by ophthalmologists to a questionnaire on treatment patterns for elevated IOP. Three steroid-responsive conditions are examined separately with the model: uveitis; postoperative inflammation following cataract surgery; and other ophthalmic inflammatory conditions (blepharitis, episcleritis, postoperative refractive surgery, and corneal transplant). The model evaluates patients with acute conditions versus those with chronic conditions and those with mild to moderate elevation of IOP versus those with severe elevation of IOP. Although the unit cost of rimexolone is higher than that of prednisolone, use of rimexolone leads to cost savings because the incidence of elevated IOP is decreased. If rimexolone is used instead of prednisolone for the treatment of ophthalmic inflammatory conditions, the estimated cost saved (at 1995 AWP prices) is approximately $10 million across the entire US population. The savings across the health maintenance organization population on an annualized basis is approximately $3.9 million. Even if rimexolone were priced higher than current market charges (at 130% to 150% of the AWP of prednisolone), cost savings ranging from the $2.9 million to $720,000 would accrue with use of rimexolone compared with prednisolone. However if, rimexolone were priced at 160% of the AWP of prednisolone, its use would incur an additional cost of $300,000. The primary medical resource utilized in treating elevated IOP in ophthalmic inflammatory conditions is physician visits. Medications are responsible for only one-fifth to one-third of the total cost of treating elevated IOP. This analysis indicates that rimexolone is associated with decreased medical resource utilization and cost savings to the entire healthcare system.

A model of the cost-effectiveness of directly observed therapy for treatment of tuberculosis

A hypothetical cohort of 25,000 TB patients and their contacts were followed for a 10-year period; rates of treatment default, infectiousness following partial treatment, relapse, hospitalization, and development of drug-resistant TB were included. The average cost per case cured was $16,846 with 15% of patients starting DOT, $17,323 with 100% starting DOT, and $20,106 with none starting DOT. The incremental cost per additional case cured was $24,064 when all patients, started treatment on DOT, indicating that outpatient DOT provides a cost-effective method of improving health outcomes for TB patients and their contacts while controlling direct costs.

The economic and clinical efficiency of point-of-care testing for critically ill patients: a decision-analysis model

Our study objective was to assess economic and clinical outcomes of use of a point-of-care (POC) blood analysis device for postoperative coronary artery bypass graft (CABG) patients. A decision analytic model was developed for patients with high expected use of blood analysis, high potential benefit from rapid turn around time of results, a large annual volume of patients, and substantial expense associated with surgery. Published literature and clinical experts provided incidence, outcome, and cost estimates associated with four clinical scenarios potentially influenced by POC testing (ventricular arrhythmias, cardiac arrest, severe postoperative bleeding, and iatrogenic anemia). We found that changes in clinical outcomes were predominantly dependent on comparative turn around time or CABG patient volume. The positive clinical impact of using POC testing was consistently associated with a positive economic impact. POC blood gas analysis may be associated with decreased incidence of adverse clinical events or earlier detection of such events, resulting in significant cost savings. This study also supports previous findings that the costs of STAT blood analysis are more personnel-related than equipment-related.

A cost-effectiveness clinical decision analysis model for schizophrenia

A model was developed to estimate the medical costs and effectiveness outcomes of three antipsychotic treatments (olanzapine, haloperidol, and risperidone) for patients with schizophrenia. A decision analytic Markov model was used to determine the cost-effectiveness of treatments and outcomes that patients treated for schizophrenia may experience over a 5-year period. Model parameter estimates were based on clinical trial data, published medical literature, and, when needed, clinician judgment. Direct medical costs were incorporated into the model, and outcomes were expressed by using three effectiveness indicators: the Brief Psychiatric Rating Scale, quality-adjusted life years, and lack of relapse. Over a 5-year period, patients on olanzapine had an additional 6.8 months in a disability-free health state based on Brief Psychiatric Rating Scale scores and more than 2 additional months in a disability-free health state based on quality-adjusted life years, and they experienced 13% fewer relapses compared with patients on haloperidol. The estimated 5-year medical cost associated with olanzapine therapy was $1,539 less than that for haloperidol therapy. Compared with risperidone therapy, olanzapine therapy cost $1,875 less over a 5-year period. Patients on olanzapine had approximately 1.6 weeks more time in a disability-free health state (based on Brief Psychiatric Rating Scale scores) and 2% fewer relapses compared with patients on risperidone. Sensitivity analyses indicated the model was sensitive to changes in drug costs and shortened hospital stay. Compared with both haloperidol and risperidone therapy, olanzapine therapy was less expensive and provided superior effectiveness outcomes even with conservative values for key parameters such as relapse and discontinuation rates.

Cost-effectiveness of thrombolytic therapy for acute myocardial infarction

OBJECTIVE

To estimate the cost-effectiveness of thrombolytic therapy versus no thrombolytic therapy for patients following acute myocardial infarction, focusing on the impact of time to treatment on outcome.

METHODS

A decision model was developed to assess the benefits, risks, and costs associated with thrombolytic therapy for treatment of acute myocardial infarction compared with standard nonthrombolytic therapy. The model used pooled data from a recent study of nine large randomized, controlled clinical trials and 12-month outcome data from a recently published meta-analysis of thrombolytic therapy trial data. Outcomes were expressed in terms of survival to hospital discharge and survival to 1 year after discharge. The risks of treatment that led to death, morbidity, or added costs were estimated. The model determined excess and marginal costs per death averted to hospital discharge and at 1 year. Results were also estimated in terms of cost per year of life saved. Sensitivity analyses included variations in time to treatment and drug cost.

RESULTS

The marginal cost of thrombolytic therapy per death averted at 1 year was $222,344, or $14,438 per year of life saved. For patients treated within 6 hours of acute myocardial infarction, the marginal cost per death averted was $181,536 at 1 year, or $11,788 per year of life saved.

CONCLUSIONS

Thrombolytic therapy is significantly more cost-effective than many other cardiovascular interventions and compares favorably with other forms of medical therapy. Results suggest that shortening the time to treatment has a critical impact on the cost-effectiveness of thrombolytic therapy.

Acute medical costs of fluoxetine versus tricyclic antidepressants. A prospective multicentre study of antidepressant drug overdoses

Despite demonstrated differences in toxicity profiles between tricyclic antidepressants (TCAs) and selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors (SSRIs), no studies have examined hospital costs associated with acute antidepressant overdoses. Given the high incidence of such overdoses, it is important to examine treatment patterns and associated costs. This prospective, multicentre cohort study compared the hospital and physician costs associated with TCA and fluoxetine drug overdoses. Over a 30-month period, 622 consecutive patients with a fluoxetine or TCA overdose presented to the emergency departments, or were admitted to intensive care or medical units, of 9 participating medical centres across the US. Inclusion criteria were: ingestion of a single antidepressant (fluoxetine or a TCA), without clinically significant co-ingestants; laboratory confirmation of the overdose; and retrievable hospital bills. Patients were followed until discharge from the emergency department or hospital. Hospital and physician charges were collected from billing data. Hospital charges were adjusted using Health Care Financing Administration cost: charge ratios to estimate costs; physician charges were adjusted to estimate costs. Patient demographic and clinical data were prospectively gathered during the course of medical treatment. Clinical data recorded included level of consciousness, cardiopulmonary complications, vital sign or ECG abnormalities, agitation, seizures, CNS depression and death. 136 patients (121 with TCA overdose and 15 with fluoxetine overdose), representing 21.8% of the 622 patients entered, met the inclusion criteria. Mean length of stay varied from 0.73 [+/-standard error of the mean (SEM) 0.33] days for fluoxetine overdose patients to 3.59 (+/-SEM 0.48) days for TCA overdose patients (p = 0.038). Mean hospital costs were $US668 for patients with a fluoxetine overdose compared with $US4691 for those with a TCA overdose (p < 0.0001). No significant differences were observed between the TCA and fluoxetine overdose groups with regard to physician costs. Median hospital and physician costs increased from $US3029 to $US4396 from the first 15-month period of the study to the second 15-month period of the study for the TCA overdose group, but decreased from $US881 to $US396 for the fluoxetine overdose group. Patients with fluoxetine overdoses had lower hospital and total medical costs compared with patients with TCA overdoses. There was some evidence supporting a reduction in the medical costs of treating fluoxetine overdoses over the 30-month study period.

Serum lipid screening to identify high-risk individuals for coronary death. The results of the Lipid Research Clinics prevalence cohort

OBJECTIVE

To assess the accuracy of specific plasma lipid fractions in predicting coronary heart disease (CHD) mortality among adults.

METHODS

Follow-up data for a random sample of 30- to 79-year-old men and women recruited into the Lipid Research Clinics Prevalence and Follow-up Studies were included in this analysis (n = 4499). Baseline measurements of total plasma cholesterol and lipoprotein fractions were compared with subsequent CHD mortality after a mean follow-up of 12.3 years. The areas under receiver operating characteristics curves for specific serum lipids were compared for individuals aged 30 to 59 and 60 to 79 years.

MAIN RESULTS

For the younger cohort, the ratio of total cholesterol to high-density lipoprotein cholesterol was a better predictor (P < .05) of CHD mortality (receiver operating characteristic curve area, 0.80 +/- 0.03) than was total cholesterol level alone (receiver operating characteristic curve area, 0.73 +/- 0.03) or any other single lipoprotein measurement. Among the older cohort, the same screening strategies performed poorly, with receiver operating characteristic curve areas ranging from 0.51 +/- 0.05 for total cholesterol to 0.64 +/- 0.05 for the ratio of low-density to high-density lipoprotein cholesterol levels.

CONCLUSION

Plasma lipid levels are poor predictors of coronary death among those aged 60 to 79 years without known CHD. These data indicate the need to define better lipid screening strategies for older, asymptomatic adults. Among younger adults aged 30 to 59 years, high-density lipoprotein cholesterol measurement should be included as part of any lipid screening program, as the ratio of total to high-density lipoprotein cholesterol levels is the best lipid screening test to identify those at high risk for subsequent CHD mortality.

Patterns of preventive practice in New Brunswick

A survey of active general practitioners was conducted in New Brunswick to ascertain their patterns of preventive practice with respect to cancer of four anatomic sites: the breast, the cervix, the colon and rectum, and the lung. Ninety-two percent of the physicians reported that they taught breast self-examination to their female patients, 98% that they performed breast examinations, 98% that they did Papanicolaou smears routinely, and 97% that they provided counselling against smoking. Few of the physicians reported that they submitted women aged 50 to 59 years to annual mammography (3%) or examined stool samples from asymptomatic patients over 44 years of age for occult blood (20%). Many (77%) said they still routinely performed chest roentgenography for early detection of lung cancer; an estimated 49% of the physicians said they performed cytologic screening of sputum samples for the same purpose. Preventive practices, when used, were usually carried out during major encounters with patients, such as general check-ups. The potential for prevention through this clinically based approach is still largely unrealized.