Role of Fatty Acid Kinase in Cellular Lipid Homeostasis and SaeRS-Dependent Virulence Factor Expression in Staphylococcus aureus

The SaeRS two-component system is a master activator of virulence factor transcription in Staphylococcus aureus, but the cellular factors that control its activity are unknown. Fatty acid (FA) kinase is a two-component enzyme system required for extracellular FA uptake and SaeRS activity. Here, we demonstrate the existence of an intracellular nonesterified FA pool in S. aureus that is elevated in strains lacking FA kinase activity. SaeRS-mediated transcription is restored in FA kinase-negative strains when the intracellular FA pool is reduced either by growth with FA-depleted bovine serum albumin to extract the FA into the medium or by the heterologous expression of Neisseria gonorrhoeae acyl-acyl carrier protein synthetase to activate FA for phospholipid synthesis. These data show that FAs act as negative regulators of SaeRS signaling, and FA kinase activates SaeRS-dependent virulence factor production by lowering inhibitory FA levels. Thus, FA kinase plays a role in cellular lipid homeostasis by activating FA for incorporation into phospholipid, and it indirectly regulates SaeRS signaling by maintaining a low intracellular FA pool.IMPORTANCE The SaeRS two-component system is a master transcriptional activator of virulence factor production in response to the host environment in S. aureus, and strains lacking FA kinase have severely attenuated SaeRS-dependent virulence factor transcription. FA kinase is required for the activation of exogenous FAs, and it plays a role in cellular lipid homeostasis by recycling cellular FAs into the phospholipid biosynthetic pathway. Activation of the sensor kinase, SaeS, is mediated by its membrane anchor domain, and the FAs which accumulate in FA kinase knockout strains are potent inhibitors of SaeS-dependent signaling. This work identifies FAs as physiological effectors for the SaeRS system and reveals a connection between cellular lipid homeostasis and the regulation of virulence factor transcription. FA kinase is widely distributed in Gram-positive bacteria, suggesting similar roles for FA kinase in these organisms.

Pyruvate Oxidase as a Critical Link between Metabolism and Capsule Biosynthesis in Streptococcus pneumoniae

The pneumococcus is one of the most prodigious producers of hydrogen peroxide amongst bacterial pathogens. Hydrogen peroxide production by the pneumococcus has been implicated in antibiotic synergism, competition between other bacterial colonizers of the nasopharynx, and damage to epithelial cells. However, the role during invasive disease has been less clear with mutants defective in hydrogen peroxide production demonstrating both attenuation and heightened invasive disease capacity depending upon strain and serotype background. This work resolves these conflicting observations by demonstrating that the main hydrogen peroxide producing enzyme of the pneumococcus, SpxB, is required for capsule formation in a strain dependent manner. Capsule production by strains harboring capsules with acetylated sugars was dependent upon the presence of spxB while capsule production in serotypes lacking such linkages were not. The spxB mutant had significantly lower steady-state cellular levels of acetyl-CoA, suggesting that loss of capsule arises from dysregulation of this intermediary metabolite. This conclusion is corroborated by deletion of pdhC, which also resulted in lower steady-state acetyl-CoA levels and phenocopied the capsule expression profile of the spxB mutant. Capsule and acetyl-CoA levels were restored in the spxB and lctO (lactate oxidase) double mutant, supporting the connection between central metabolism and capsule formation. Taken together, these data show that the defect in pathogenesis in the spxB mutant is due to a metabolic imbalance that attenuates capsule formation and not to reduced hydrogen peroxide formation.

The pneumococcus polysaccharide capsule is one of the most critical virulence determinants produced by this major human pathogen. The pneumococcus also produces prodigious amounts of hydrogen peroxide via the enzymatic reaction catalyzed by pyruvate oxidase, SpxB. Deletion of spxB resulted in the loss of surface polysaccharide capsule production in a serotype dependent manner with a mirrored effect on the virulence of the mutants. We observed that deletion of spxB reduced the steady-state levels of acetyl-CoA, a key metabolic intermediate in peptidoglycan, fatty acid biosynthesis, and in capsule biosynthesis in a subset of serotypes. These data suggest that the defect in capsule production was due to altered metabolism that results in reduced acetyl-CoA availability. Corroborating these data, we found that capsule biosynthesis was impaired upon loss of PDHC, an additional metabolic enzyme that generates acetyl-CoA. These data reveal a critical link between pneumococcal metabolism and capsule biosynthesis as well as provide a striking example of how a virulence gene can have a differential contribution to pathogenesis dependent upon strain background.

Electrical Cell-Substrate Impedance Spectroscopy Can Monitor Age-Grouped Human Adipose Stem Cell Variability During Osteogenic Differentiation

Human adipose stem cells (hASCs) are an attractive cell source for bone tissue engineering applications. However, a critical issue to be addressed before widespread hASC clinical translation is the dramatic variability in proliferative capacity and osteogenic potential among hASCs isolated from different donors. The goal of this study was to test our hypothesis that electrical cell-substrate impedance spectroscopy (ECIS) could track complex bioimpedance patterns of hASCs throughout proliferation and osteogenic differentiation to better understand and predict variability among hASC populations. Superlots composed of hASCs from young (aged 24-36 years), middle-aged (aged 48-55 years), and elderly (aged 60-81 years) donors were seeded on gold electrode arrays. Complex impedance measurements were taken throughout proliferation and osteogenic differentiation. During osteogenic differentiation, four impedance phases were identified: increase, primary stabilization, drop phase, and secondary stabilization. Matrix deposition was first observed 48-96 hours after the impedance maximum, indicating, for the first time, that ECIS can identify morphological changes that correspond to late-stage osteogenic differentiation. The impedance maximum was observed at day 10.0 in young, day 6.1 in middle-aged, and day 1.3 in elderly hASCs, suggesting that hASCs from younger donors require a longer time to differentiate than do hASCs from older donors, but young hASCs proliferated more and accreted more calcium long-term. This is the first study to use ECIS to predict osteogenic potential of multiple hASC populations and to show that donor age may temporally control onset of osteogenesis. These findings could be critical for development of patient-specific bone tissue engineering and regenerative medicine therapies. Stem Cells Translational Medicine 2017;6:502-511.

Activation of Exogenous Fatty Acids to Acyl-Acyl Carrier Protein Cannot Bypass FabI Inhibition in Neisseria

Neisseria is a Gram-negative pathogen with phospholipids composed of straight chain saturated and monounsaturated fatty acids, the ability to incorporate exogenous fatty acids, and lipopolysaccharides that are not essential. The FabI inhibitor, AFN-1252, was deployed as a chemical biology tool to determine whether Neisseria can bypass the inhibition of fatty acid synthesis by incorporating exogenous fatty acids. Neisseria encodes a functional FabI that was potently inhibited by AFN-1252. AFN-1252 caused a dose-dependent inhibition of fatty acid synthesis in growing Neisseria, a delayed inhibition of growth phenotype, and minimal inhibition of DNA, RNA, and protein synthesis, showing that its mode of action is through inhibiting fatty acid synthesis. Isotopic fatty acid labeling experiments showed that Neisseria encodes the ability to incorporate exogenous fatty acids into its phospholipids by an acyl-acyl carrier protein-dependent pathway. However, AFN-1252 remained an effective antibacterial when Neisseria were supplemented with exogenous fatty acids. These results demonstrate that extracellular fatty acids are activated by an acyl-acyl carrier protein synthetase (AasN) and validate type II fatty acid synthesis (FabI) as a therapeutic target against Neisseria.

Maternal bile acid transporter deficiency promotes neonatal demise

Intrahepatic cholestasis of pregnancy (ICP) is associated with adverse neonatal survival and is estimated to impact between 0.4 and 5% of pregnancies worldwide. Here we show that maternal cholestasis (due to Abcb11 deficiency) produces neonatal death among all offspring within 24 h of birth due to atelectasis-producing pulmonary hypoxia, which recapitulates the neonatal respiratory distress of human ICP. Neonates of Abcb11-deficient mothers have elevated pulmonary bile acids and altered pulmonary surfactant structure. Maternal absence of Nr1i2 superimposed on Abcb11 deficiency strongly reduces maternal serum bile acid concentrations and increases neonatal survival. We identify pulmonary bile acids as a key factor in the disruption of the structure of pulmonary surfactant in neonates of ICP. These findings have important implications for neonatal respiratory failure, especially when maternal bile acids are elevated during pregnancy, and highlight potential pathways and targets amenable to therapeutic intervention to ameliorate this condition.

Chlamydia trachomatis Scavenges Host Fatty Acids for Phospholipid Synthesis via an Acyl-Acyl Carrier Protein Synthetase

The obligate intracellular parasite Chlamydia trachomatis has a reduced genome but relies on de novo fatty acid and phospholipid biosynthesis to produce its membrane phospholipids. Lipidomic analyses showed that 8% of the phospholipid molecular species synthesized by C. trachomatis contained oleic acid, an abundant host fatty acid that cannot be made by the bacterium. Mass tracing experiments showed that isotopically labeled palmitic, myristic, and lauric acids added to the medium were incorporated into C. trachomatis-derived phospholipid molecular species. HeLa cells did not elongate lauric acid, but infected HeLa cell cultures elongated laurate to myristate and palmitate. The elongated fatty acids were incorporated exclusively into C. trachomatis-produced phospholipid molecular species. C. trachomatis has adjacent genes encoding the separate domains of the bifunctional acyl-acyl carrier protein (ACP) synthetase/2-acylglycerolphosphoethanolamine acyltransferase gene (aas) of Escherichia coli. The CT775 gene encodes an acyltransferase (LpaT) that selectively transfers fatty acids from acyl-ACP to the 1-position of 2-acyl-glycerophospholipids. The CT776 gene encodes an acyl-ACP synthetase (AasC) with a substrate preference for palmitic compared with oleic acid in vitro. Exogenous fatty acids were elongated and incorporated into phospholipids by Escherichia coli-expressing AasC, illustrating its function as an acyl-ACP synthetase in vivo. These data point to an AasC-dependent pathway in C. trachomatis that selectively scavenges host saturated fatty acids to be used for the de novo synthesis of its membrane constituents.

Chlamydia trachomatis Relies on Autonomous Phospholipid Synthesis for Membrane Biogenesis

The obligate intracellular parasite Chlamydia trachomatis has a reduced genome and is thought to rely on its mammalian host cell for nutrients. Although several lines of evidence suggest C. trachomatis utilizes host phospholipids, the bacterium encodes all the genes necessary for fatty acid and phospholipid synthesis found in free living Gram-negative bacteria. Bacterially derived phospholipids significantly increased in infected HeLa cell cultures. These new phospholipids had a distinct molecular species composition consisting of saturated and branched-chain fatty acids. Biochemical analysis established the role of C. trachomatis-encoded acyltransferases in producing the new disaturated molecular species. There was no evidence for the remodeling of host phospholipids and no change in the size or molecular species composition of the phosphatidylcholine pool in infected HeLa cells. Host sphingomyelin was associated with C. trachomatis isolated by detergent extraction, but it may represent contamination with detergent-insoluble host lipids rather than being an integral bacterial membrane component. C. trachomatis assembles its membrane systems from the unique phospholipid molecular species produced by its own fatty acid and phospholipid biosynthetic machinery utilizing glucose, isoleucine, and serine.

A thioesterase bypasses the requirement for exogenous fatty acids in the plsX deletion of Streptococcus pneumoniae

PlsX is an acyl-acyl carrier protein (ACP):phosphate transacylase that interconverts the two acyl donors in Gram-positive bacterial phospholipid synthesis. The deletion of plsX in Staphylococcus aureus results in a requirement for both exogenous fatty acids and de novo type II fatty acid biosynthesis. Deletion of plsX (SP0037) in Streptococcus pneumoniae did not result in an auxotrophic phenotype. The ΔplsX S. pneumoniae strain was refractory to myristic acid-dependent growth arrest, and unlike the wild-type strain, was susceptible to fatty acid synthesis inhibitors in the presence of exogenous oleate. The ΔplsX strain contained longer chain saturated fatty acids imparting a distinctly altered phospholipid molecular species profile. An elevated pool of 18- and 20-carbon saturated fatty acids was detected in the ΔplsX strain. A S. pneumoniae thioesterase (TesS, SP1408) hydrolyzed acyl-ACP in vitro, and the ΔtesS ΔplsX double knockout strain was a fatty acid auxotroph. Thus, the TesS thioesterase hydrolyzed the accumulating acyl-ACP in the ΔplsX strain to liberate fatty acids that were activated by fatty acid kinase to bypass a requirement for extracellular fatty acid. This work identifies tesS as the gene responsible for the difference in exogenous fatty acid growth requirement of the ΔplsX strains of S. aureus and S. pneumoniae.

Incorporation of extracellular fatty acids by a fatty acid kinase-dependent pathway in Staphylococcus aureus

Acyl-CoA and acyl-acyl carrier protein (ACP) synthetases activate exogenous fatty acids for incorporation into phospholipids in Gram-negative bacteria. However, Gram-positive bacteria utilize an acyltransferase pathway for the biogenesis of phosphatidic acid that begins with the acylation of sn-glycerol-3-phosphate by PlsY using an acyl-phosphate (acyl-PO4 ) intermediate. PlsX generates acyl-PO4 from the acyl-ACP end-products of fatty acid synthesis. The plsX gene of Staphylococcus aureus was inactivated and the resulting strain was both a fatty acid auxotroph and required de novo fatty acid synthesis for growth. Exogenous fatty acids were only incorporated into the 1-position and endogenous acyl groups were channeled into the 2-position of the phospholipids in strain PDJ39 (ΔplsX). Extracellular fatty acids were not elongated. Removal of the exogenous fatty acid supplement led to the rapid accumulation of intracellular acyl-ACP and the abrupt cessation of fatty acid synthesis. Extracts from the ΔplsX strain exhibited an ATP-dependent fatty acid kinase activity, and the acyl-PO4 was converted to acyl-ACP when purified PlsX is added. These data reveal the existence of a novel fatty acid kinase pathway for the incorporation of exogenous fatty acids into S. aureus phospholipids.

Elimination of the CDP-ethanolamine pathway disrupts hepatic lipid homeostasis

Phosphoethanolamine cytidylyltransferase (ECT) catalyzes the rate-controlling step in a major pathway for the synthesis of phosphatidylethanolamine (PtdEtn). Hepatocyte-specific deletion of the ECT gene in mice resulted in normal appearing animals without overt signs of liver injury or inflammation. The molecular species of PtdEtn in the ECT-deficient livers were significantly altered compared with controls and matched the composition of the phosphatidylserine (PtdSer) pool, illustrating the complete reliance on the PtdSer decarboxylase pathway for PtdEtn synthesis. PtdSer structure was controlled by the substrate specificity of PtdSer synthase that selectively converted phosphatidylcholine molecular species containing stearate paired with a polyunsaturated fatty acid to PtdSer. There was no evidence for fatty acid remodeling of PtdEtn. The elimination of diacylglycerol utilization by the CDP-ethanolamine pathway led to a 10-fold increase in triacylglycerols in the ECT-deficient hepatocytes that became engorged with lipid droplets. Triacylglycerol accumulation was associated with a significant elevation in the expression of the transcription factors and target genes that drive de novo lipogenesis. The absence of the ECT pathway for diacylglycerol utilization at the endoplasmic reticulum triggers increased fatty acid synthesis to support the formation of triacylglycerols leading to liver steatosis.

PqsD is responsible for the synthesis of 2,4-dihydroxyquinoline, an extracellular metabolite produced by Pseudomonas aeruginosa

2,4-Dihydroxyquinoline (DHQ) is an abundant extracellular metabolite of the opportunistic pathogen Pseudomonas aeruginosa that is secreted into growth medium in stationary phase to concentrations comparable with those of the Pseudomonas quinolone signal. Using a combination of biochemical and genetic approaches, we show that PqsD, a condensing enzyme in the pqs operon that is essential for Pseudomonas quinolone signal synthesis, accounts for DHQ formation in vivo. First, the anthraniloyl moiety is transferred to the active-site Cys of PqsD to form an anthraniloyl-PqsD intermediate, which then condenses with either malonyl-CoA or malonyl-acyl carrier protein to produce 3-(2-aminophenyl)-3-oxopropanoyl-CoA. This short-lived intermediate undergoes an intramolecular rearrangement to form DHQ. DHQ was produced by Escherichia coli coexpressing PqsA and PqsD, illustrating that these two proteins are the only factors necessary for DHQ synthesis. Thus, PqsD is responsible for the production of DHQ in P. aeruginosa.

A Pseudomonas aeruginosa transcription factor that senses fatty acid structure

Cells regulate their membrane phospholipid biophysical properties by the co-ordinated synthesis of saturated and unsaturated fatty acids. In bacteria, unsaturated fatty acids are produced by the de novo fatty acid biosynthetic pathway anaerobically, or by oxidative desaturation of the existing fatty acids catalysed by desaturases. A transcriptional repressor in Pseudomonas aeruginosa, DesT (PA4890), regulates the expression of an acyl-CoA desaturase operon (desCB, PA4889 and PA4888). The desCB operon is located adjacent to desT and is transcribed in the opposite direction. The expression level of desCB is strongly and selectively upregulated in a DeltadesT-deletion strain. Both electrophoresis mobility shift assay and DNase I footprinting analysis demonstrated the existence of two DesT binding sites in the desT-desCB promoter region, P1 and P2. The binding of purified DesT to P2 was enhanced by unsaturated acyl-CoAs, whereas saturated acyl-CoAs prevented DesT interaction with P2. The biological importance of this interaction was verified by the upregulation of desCB and desT in cells grown in the presence of stearate and their repression when oleate was present. This unique ligand selectivity allows DesT to sense the physical properties of the cellular acyl-CoA pool and modulate the expression of the acyl-CoA Delta9-desaturase system to adjust fatty acid desaturation activity accordingly.

Serum opacity factor, a streptococcal virulence factor that binds to apolipoproteins A-I and A-II and disrupts high density lipoprotein structure

Serum opacity factor (SOF) is a virulence determinant of group A streptococci that opacifies mammalian sera. We analyzed the specificity and mechanism of the opacity reaction using a recombinant form of the amino-terminal opacification domain of SOF, rSOF. Our data indicate that rSOF is neither a protease nor a lipase, but rather it is the binding of rSOF to high density lipoprotein (HDL) that triggers the opacity reaction. rSOF did not opacify plasma from apoA-I(-/-) mice or purified low or very low density lipoproteins but readily opacified HDL. rSOF binding to HDL was characterized by two high affinity binding sites; it bound to apoA-I (K(d) = 6 nm) and apoA-II (K(d) = 30 nm), and both apoA-I and apoA-II blocked the binding of rSOF to HDL. Electron microscopic examination and biochemical analyses of HDL treated with rSOF revealed the formation of lipid droplets devoid of apolipoproteins. Thus, SOF interacts with HDL in human blood by binding to apoA-I and apoA-II and causing the release of HDL lipid cargo, which coalesces to form lipid droplets, resulting in opacification. The disruption of HDL may attenuate its anti-inflammatory functions and contribute to the pathogenesis of group A streptococcal infections.

Lysophospholipid Flipping across the Escherichia coli Inner Membrane Catalyzed by a Transporter (LplT) Belonging to the Major Facilitator Superfamily

The transfer of phospholipids across membrane bilayers is protein-mediated, and most of the established transporters catalyze the energy-dependent efflux of phospholipids from cells. This work identifies and characterizes a lysophospholipid transporter gene (lplT, formally ygeD) in Escherichia coli that is an integral component in the 2-acylglycerophosphoethanolamine (2-acyl-GPE) metabolic cycle for membrane protein acylation. The lplT gene is adjacent to and in the same operon as the aas gene, which encodes the bifunctional enzyme 2-acyl-GPE acyltransferase/acyl-acyl carrier protein synthetase. In some bacteria, acyltransferase/acyl-ACP synthetase (Aas) and LplT homologues are fused in a single polypeptide chain. 2-Acyl-GPE transport to the inside of the cell was assessed by measuring the Aas-dependent formation of phosphatidylethanolamine. The Aas-dependent incorporation of [3H]palmitate into phosphatidylethanolamine was significantly diminished in deltalplT mutants, and the LplT-Aas transport/acylation activity was independent of the proton motive force. The deltalplT mutants accumulated acyl-GPE in vivo and had a diminished capacity to transport exogenous 2-acylglycerophosphocholine into the cell. Spheroplasts prepared from wild-type E. coli transported and acylated fluorescent 2-acyl-GPE with an apparent K(d) of 7.5 microM, whereas this high-affinity process was absent in deltalplT mutants. Thus, LplT catalyzes the transbilayer movement of lysophospholipids and is the first example of a phospholipid flippase that belongs to the major facilitator superfamily.

Acyl carrier protein is a cellular target for the antibacterial action of the pantothenamide class of pantothenate antimetabolites

Pantothenate is the precursor of the essential cofactor coenzyme A (CoA). Pantothenate kinase (CoaA) catalyzes the first and regulatory step in the CoA biosynthetic pathway. The pantothenate analogs N-pentylpantothenamide and N-heptylpantothenamide possess antibiotic activity against Escherichia coli. Both compounds are substrates for E. coli CoaA and competitively inhibit the phosphorylation of pantothenate. The phosphorylated pantothenamides are further converted to CoA analogs, which were previously predicted to act as inhibitors of CoA-dependent enzymes. Here we show that the mechanism for the toxicity of the pantothenamides is due to the inhibition of fatty acid biosynthesis through the formation and accumulation of the inactive acyl carrier protein (ACP), which was easily observed as a faster migrating protein using conformationally sensitive gel electrophoresis. E. coli treated with the pantothenamides lost the ability to incorporate [1-(14)C]acetate to its membrane lipids, indicative of the inhibition of fatty acid synthesis. Cellular CoA was maintained at the level sufficient for bacterial protein synthesis. Electrospray ionization time-of-flight mass spectrometry confirmed that the inactive ACP was the product of the transfer of the inactive phosphopantothenamide moiety of the CoA analog to apo-ACP, forming the ACP analog that lacks the sulfhydryl group for the attachment of acyl chains for fatty acid synthesis. Inactive ACP accumulated in pantothenamide-treated cells because of the active hydrolysis of regular ACP and the slow turnover of the inactive prosthetic group. Thus, the pantothenamides are pro-antibiotics that inhibit fatty acid synthesis and bacterial growth because of the covalent modification of ACP.

A population-based assessment of human rights abuses committed against ethnic Albanian refugees from Kosovo

OBJECTIVES

This study assessed patterns of displacement and human rights abuses among Kosovar refugees in Macedonia and Albania.

METHODS

Between April 19 and May 3, 1999, 1180 ethnic Albanian refugees living in 31 refugee camps and collective centers in Macedonia and Albania were interviewed.

RESULTS

The majority (68%) of participants reported that their families were directly expelled from their homes by Serb forces. Overall, 50% of participants saw Serb police or soldiers burning the houses of others, 16% saw Serb police or soldiers burn their own home, and 14% witnessed Serb police or soldiers killing someone. Large percentages of participants saw destroyed mosques, schools, or medical facilities. Thirty-one percent of respondents reported human rights abuses committed against their household members, including beatings, killings, torture, forced separation and disappearances, gunshot wounds, and sexual assault.

CONCLUSIONS

The present findings confirm that Serb forces engaged in a systematic and brutal campaign to forcibly expel the ethnic Albanian population of Kosovo. In the course of these mass deportations, Serb forces committed widespread abuses of human rights against ethnic Albanians.

Two-stage elephant trunk reconstruction for aneurysm of an aberrant right subclavian artery in association with aneurysmal distal aortic arch and descending thoracic aorta

Surgical treatment of the combination of aneurysms of an aberrant right subclavian artery, distal aortic arch, and descending thoracic aorta requires control of structures in both the right and the left hemithorax. We report a 2-stage surgical approach. The 1st stage, performed through a median sternotomy, consists of an elephant trunk reconstruction and an interposition graft to the ligated aberrant right subclavian artery. The 2nd stage, performed through a left thoracotomy is an interposition graft from the elephant trunk to the distal descending thoracic aorta.

Virginity examinations in Turkey: role of forensic physicians in controlling female sexuality

CONTEXT

Although the Turkish Medical Association has deemed "virginity examinations" a form of gender-based violence, women in Turkey are often subjected to such examinations by forensic physicians for both legal and social reasons. Little is known about these physicians' role and attitudes in this practice.

OBJECTIVES

To assess forensic physicians' experiences and attitudes regarding virginity examinations in Turkey and suggest potential solutions to the problems identified.

DESIGN

Cross-sectional self-administered survey.

SETTING

Surveys were completed during the Forensic Science Congress held in Kusadasi in April 1998 as well as in urban academic and medical practice settings between April and October 1998.

PARTICIPANTS

Of 158 physicians who practice, are formally trained in, or are in training for forensic medicine, 118 completed the survey (response rate, 74.7%).

MAIN OUTCOME MEASURES

Frequency and circumstances of conducting virginity examinations, opinions regarding beneficial and adverse consequences of these examinations, and recommendations for changing the practice, as measured by a 100-item questionnaire.

RESULTS

Overall, survey respondents reported conducting 5901 examinations in the previous 12 months; 4045 were conducted because of alleged sexual assault and 1856 for social reasons. Although 68% of forensic physicians indicated that they believed virginity examinations are inappropriate in the absence of an allegation of sexual assault, 45% had conducted examinations for social reasons. The majority of the respondents (93%) agreed that the examinations are psychologically traumatic for the patient. In addition, more than half (58%) reported that at least 50% of patients undergo examinations against their will.

CONCLUSIONS

Nearly half of forensic physicians in Turkey conduct virginity examinations for social reasons despite beliefs that such examinations are inappropriate, traumatic to the patient, and often performed against the patient's will. Physicians' participation in such practices is inconsistent with principles of bioethics and international human rights.

Axillary thoracoscopy

Thoracoscopy can be done safely and effectively through working ports placed in the axilla in patients whose pathology is in the upper half of the thorax. We have used this technique successfully in 37 patients with no complications. Advantages include superior cosmesis, optimal access to the apex of the chest, and, if necessary, easy conversion to axillary thoracotomy.