Cell-specific modulation of mitochondrial respiration and metabolism by the pro-apoptotic Bcl-2 family members Bax and Bak.

Proteins from the Bcl-2 family play an essential role in the regulation of apoptosis. However, they also possess cell death-unrelated activities that are less well understood. This prompted us to study apoptosis-unrelated activities of the Bax and Bak, pro-apoptotic members of the Bcl-2 family. We prepared Bax/Bak-deficient human cancer cells of different origin and found that while respiration in the glioblastoma U87 Bax/Bak-deficient cells was greatly enhanced, respiration of Bax/Bak-deficient B lymphoma HBL-2 cells was slightly suppressed. Bax/Bak-deficient U87 cells also proliferated faster in culture, formed tumours more rapidly in mice, and showed modulation of metabolism with a considerably increased NAD+/NADH ratio. Follow-up analyses documented increased/decreased expression of mitochondria-encoded subunits of respiratory complexes and stabilization/destabilization of the mitochondrial transcription elongation factor TEFM in Bax/Bak-deficient U87 and HBL-2 cells, respectively. TEFM downregulation using shRNAs attenuated mitochondrial respiration in Bax/Bak-deficient U87 as well as in parental HBL-2 cells. We propose that (post)translational regulation of TEFM levels in Bax/Bak-deficient cells modulates levels of subunits of mitochondrial respiratory complexes that, in turn, contribute to respiration and the accompanying changes in metabolism and proliferation in these cells.

Astrocyte-like subpopulation of NG2 glia in the adult mouse cortex exhibits characteristics of neural progenitor cells.

Glial cells expressing neuron-glial antigen 2 (NG2), also known as oligodendrocyte progenitor cells (OPCs), play a critical role in maintaining brain health. However, their ability to differentiate after ischemic injury is poorly understood. The aim of this study was to investigate the properties and functions of NG2 glia in the ischemic brain. Using transgenic mice, we selectively labeled NG2-expressing cells and their progeny in both healthy brain and after focal cerebral ischemia (FCI). Using single-cell RNA sequencing, we classified the labeled glial cells into five distinct subpopulations based on their gene expression patterns. Additionally, we examined the membrane properties of these cells using the patch-clamp technique. Of the identified subpopulations, three were identified as OPCs, whereas the fourth subpopulation had characteristics indicative of cells likely to develop into oligodendrocytes. The fifth subpopulation of NG2 glia showed astrocytic markers and had similarities to neural progenitor cells. Interestingly, this subpopulation was present in both healthy and post-ischemic tissue; however, its gene expression profile changed after ischemia, with increased numbers of genes related to neurogenesis. Immunohistochemical analysis confirmed the temporal expression of neurogenic genes and showed an increased presence of NG2 cells positive for Purkinje cell protein-4 at the periphery of the ischemic lesion 12 days after FCI, as well as NeuN-positive NG2 cells 28 and 60 days after injury. These results suggest the potential development of neuron-like cells arising from NG2 glia in the ischemic tissue. Our study provides insights into the plasticity of NG2 glia and their capacity for neurogenesis after stroke.

Astrocytic TRPV4 Channels and Their Role in Brain Ischemia.

Transient receptor potential cation channels subfamily V member 4 (TRPV4) are non-selective cation channels expressed in different cell types of the central nervous system. These channels can be activated by diverse physical and chemical stimuli, including heat and mechanical stress. In astrocytes, they are involved in the modulation of neuronal excitability, control of blood flow, and brain edema formation. All these processes are significantly impaired in cerebral ischemia due to insufficient blood supply to the tissue, resulting in energy depletion, ionic disbalance, and excitotoxicity. The polymodal cation channel TRPV4, which mediates Ca2+ influx into the cell because of activation by various stimuli, is one of the potential therapeutic targets in the treatment of cerebral ischemia. However, its expression and function vary significantly between brain cell types, and therefore, the effect of its modulation in healthy tissue and pathology needs to be carefully studied and evaluated. In this review, we provide a summary of available information on TRPV4 channels and their expression in healthy and injured neural cells, with a particular focus on their role in ischemic brain injury.

The absence of AQP4/TRPV4 complex substantially reduces acute cytotoxic edema following ischemic injury.

Introduction: Astrocytic Aquaporin 4 (AQP4) and Transient receptor potential vanilloid 4 (TRPV4) channels form a functional complex that likely influences cell volume regulation, the development of brain edema, and the severity of the ischemic injury. However, it remains to be fully elucidated whether blocking these channels can serve as a therapeutic approach to alleviate the consequences of having a stroke. Methods and results: In this study, we used in vivo magnetic resonance imaging (MRI) to quantify the extent of brain lesions one day (D1) and seven days (D7) after permanent middle cerebral artery occlusion (pMCAO) in AQP4 or TRPV4 knockouts and mice with simultaneous deletion of both channels. Our results showed that deletion of AQP4 or TRPV4 channels alone leads to a significant worsening of ischemic brain injury at both time points, whereas their simultaneous deletion results in a smaller brain lesion at D1 but equal tissue damage at D7 when compared with controls. Immunohistochemical analysis 7 days after pMCAO confirmed the MRI data, as the brain lesion was significantly greater in AQP4 or TRPV4 knockouts than in controls and double knockouts. For a closer inspection of the TRPV4 and AQP4 channel complex in the development of brain edema, we applied a real-time iontophoretic method in situ to determine ECS diffusion parameters, namely volume fraction (α) and tortuosity (λ). Changes in these parameters reflect alterations in cell volume, and tissue structure during exposure of acute brain slices to models of ischemic conditions in situ, such as oxygen-glucose deprivation (OGD), hypoosmotic stress, or hyperkalemia. The decrease in α was comparable in double knockouts and controls when exposed to hypoosmotic stress or hyperkalemia. However, during OGD, there was no decrease in α in the double knockouts as observed in the controls, which suggests less swelling of the cellular components of the brain. Conclusion: Although simultaneous deletion of AQP4 and TRPV4 did not improve the overall outcome of ischemic brain injury, our data indicate that the interplay between AQP4 and TRPV4 channels plays a critical role during neuronal and non-neuronal swelling in the acute phase of ischemic injury.

Early diagnosis of systemic scleroderma.

Systemic scleroderma (SSc) is a systemic immune-mediated connective tissue disease characterized by fibroproductive changes in connective tissue and microvascular disorders. The disease affects the skin, musculoskeletal system and internal organs. It is a disease with a significant rate of morbidity and mortality, significantly worsening the quality of life of patients. Early initiation of therapy is necessary to prevent disease progression. This review article discusses the current possibilities of early diagnosis of systemic scleroderma.

On the Common Journey of Neural Cells through Ischemic Brain Injury and Alzheimer's Disease.

Ischemic brain injury and Alzheimer's disease (AD) both lead to cell death in the central nervous system (CNS) and thus negatively affect particularly the elderly population. Due to the lack of a definitive cure for brain ischemia and AD, it is advisable to carefully study, compare, and contrast the mechanisms that trigger, and are involved in, both neuropathologies. A deeper understanding of these mechanisms may help ameliorate, or even prevent, the destructive effects of neurodegenerative disorders. In this review, we deal with ischemic damage and AD, with the main emphasis on the common properties of these CNS disorders. Importantly, we discuss the Wnt signaling pathway as a significant factor in the cell fate determination and cell survival in the diseased adult CNS. Finally, we summarize the interesting findings that may improve or complement the current sparse and insufficient treatments for brain ischemia and AD, and we delineate prospective directions in regenerative medicine.

Compromised Astrocyte Swelling/Volume Regulation in the Hippocampus of the Triple Transgenic Mouse Model of Alzheimer's Disease.

In this study, we aimed to disclose the impact of amyloid-ß toxicity and tau pathology on astrocyte swelling, their volume recovery and extracellular space (ECS) diffusion parameters, namely volume fraction (α) and tortuosity (λ), in a triple transgenic mouse model of Alzheimer's disease (3xTg-AD). Astrocyte volume changes, which reflect astrocyte ability to take up ions/neurotransmitters, were quantified during and after exposure to hypo-osmotic stress, or hyperkalemia in acute hippocampal slices, and were correlated with alterations in ECS diffusion parameters. Astrocyte volume and ECS diffusion parameters were monitored during physiological aging (controls) and during AD progression in 3-, 9-, 12- and 18-month-old mice. In the hippocampus of controls α gradually declined with age, while it remained unaffected in 3xTg-AD mice during the entire time course. Moreover, age-related increases in λ occurred much earlier in 3xTg-AD animals than in controls. In 3xTg-AD mice changes in α induced by hypo-osmotic stress or hyperkalemia were comparable to those observed in controls, however, AD progression affected α recovery following exposure to both. Compared to controls, a smaller astrocyte swelling was detected in 3xTg-AD mice only during hyperkalemia. Since we observed a large variance in astrocyte swelling/volume regulation, we divided them into high- (HRA) and low-responding astrocytes (LRA). In response to hyperkalemia, the incidence of LRA was higher in 3xTg-AD mice than in controls, which may also reflect compromised K+ and neurotransmitter uptake. Furthermore, we performed single-cell RT-qPCR to identify possible age-related alterations in astrocytic gene expression profiles. Already in 3-month-old 3xTg-AD mice, we detected a downregulation of genes affecting the ion/neurotransmitter uptake and cell volume regulation, namely genes of glutamate transporters, α2ß2 subunit of Na+/K+-ATPase, connexin 30 or Kir4.1 channel. In conclusion, the aged hippocampus of 3xTg-AD mice displays an enlarged ECS volume fraction and an increased number of obstacles, which emerge earlier than in physiological aging. Both these changes may strongly affect intercellular communication and influence astrocyte ionic/neurotransmitter uptake, which becomes impaired during aging and this phenomenon is manifested earlier in 3xTg-AD mice. The increased incidence of astrocytes with limited ability to take up ions/neurotransmitters may further add to a cytotoxic environment.

Glial Cells-The Strategic Targets in Amyotrophic Lateral Sclerosis Treatment.

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease, which is characterized by the degeneration of motor neurons in the motor cortex and the spinal cord and subsequently by muscle atrophy. To date, numerous gene mutations have been linked to both sporadic and familial ALS, but the effort of many experimental groups to develop a suitable therapy has not, as of yet, proven successful. The original focus was on the degenerating motor neurons, when researchers tried to understand the pathological mechanisms that cause their slow death. However, it was soon discovered that ALS is a complicated and diverse pathology, where not only neurons, but also other cell types, play a crucial role via the so-called non-cell autonomous effect, which strongly deteriorates neuronal conditions. Subsequently, variable glia-based in vitro and in vivo models of ALS were established and used for brand-new experimental and clinical approaches. Such a shift towards glia soon bore its fruit in the form of several clinical studies, which more or less successfully tried to ward the unfavourable prognosis of ALS progression off. In this review, we aimed to summarize current knowledge regarding the involvement of each glial cell type in the progression of ALS, currently available treatments, and to provide an overview of diverse clinical trials covering pharmacological approaches, gene, and cell therapies.

The role of aquaporin-4 and transient receptor potential vaniloid isoform 4 channels in the development of cytotoxic edema and associated extracellular diffusion parameter changes.

The proper function of the nervous system is dependent on the balance of ions and water between the intracellular and extracellular space (ECS). It has been suggested that the interaction of aquaporin-4 (AQP4) and the transient receptor potential vaniloid isoform 4 (TRPV4) channels play a role in water balance and cell volume regulation, and indirectly, of the ECS volume. Using the real-time iontophoretic method, we studied the changes of the ECS diffusion parameters: ECS volume fraction α (α = ECS volume fraction/total tissue volume) and tortuosity λ (λ2  = free/apparent diffusion coefficient) in mice with a genetic deficiency of AQP4 or TRPV4 channels, and in control animals. The used models of cytotoxic edema included: mild and severe hypotonic stress or oxygen-glucose deprivation (OGD) in situ and terminal ischemia/anoxia in vivo. This study shows that an AQP4 or TRPV4 deficit slows down the ECS volume shrinkage during severe ischemia in vivo. We further demonstrate that a TRPV4 deficit slows down the velocity and attenuates an extent of the ECS volume decrease during OGD treatment in situ. However, in any of the cytotoxic edema models in situ (OGD, mild or severe hypotonic stress), we did not detect any alterations in the cell swelling or volume regulation caused by AQP4 deficiency. Overall, our results indicate that the AQP4 and TRPV4 channels may play a crucial role in severe pathological states associated with their overexpression and enhanced cell swelling. However, detailed interplay between AQP4 and TRPV4 channels requires further studies and additional research.

The Contribution of TRPV4 Channels to Astrocyte Volume Regulation and Brain Edema Formation.

Transient receptor potential vanilloid type 4 (TRPV4) channels are involved in astrocyte volume regulation; however, only limited data exist about its mechanism in astrocytes in situ. We performed middle cerebral artery occlusion in adult mice, where we found twice larger edema 1 day after the insult in trpv4-/- mice compared to the controls, which was quantified using magnetic resonance imaging. This result suggests disrupted volume regulation in the brain cells in trpv4-/- mice leading to increased edema formation. The aim of our study was to elucidate whether TRPV4 channel-based volume regulation occurs in astrocytes in situ and whether the disrupted volume regulation in trpv4-/- mice might lead to higher edema formation after brain ischemia. For our experiments, we used trpv4-/- mice crossed with transgenic mice expressing enhanced green fluorescent protein (EGFP) under the control of the glial fibrillary acidic protein promoter, which leads to astrocyte visualization by EGFP expression. For quantification of astrocyte volume changes, we used two-dimensional (2D) and three-dimensional (3D) morphometrical approaches and a quantification algorithm based on fluorescence intensity changes during volume alterations induced by hypotonicity or by oxygen-glucose deprivation. In contrast to in vitro experiments, we found little evidence of the contribution of TRPV4 channels to volume regulation in astrocytes in situ in adult mice. Moreover, we only found a rare expression of TRPV4 channels in adult mouse astrocytes. Our data suggest that TRPV4 channels are not involved in astrocyte volume regulation in situ; however, they play a protective role during the ischemia-induced brain edema formation.

Cell volume changes as revealed by fluorescence microscopy: Global vs local approaches.

BACKGROUND: Several techniques for cell volume measurement using fluorescence microscopy have been established to date. In this study, we compare the performance of three different approaches which allow for estimations of the cell volume changes in biological samples containing individual fluorescently labeled cells either in culture or in the tissue context. The specific requirements, limitations and advantages of individual approaches are discussed. NEW METHOD: Global morphometric data are quantitatively compared with local information about the overall cell volume, represented by the concentration of a mobile fluorophore accumulated within the monitored cell. RESULTS: Volume changes induced by variations in the extracellular osmolarity in murine fibroblasts and astrocytes either in the culture or in the acute brain slices were registered by the three- and two-dimensional morphometries and by local fluorescence intensity measurements. The performance of the latter approach was verified using FRAP assessment of the fluorophore mobility. Significantly lower amplitudes of the cortical astrocytes swelling were detected by three-dimensional morphometry, when compared to the other two approaches. Consequently, it failed to detect temperature-induced cell volume changes. COMPARISON WITH EXISTING METHOD(S): The three most popular methods of cell volume measurement are compared to each other in this study. CONCLUSIONS: We show that the effectivity of global morphometry-based volumetric approaches drops with the increasing cell shape complexity or in the tissue context. In contrast to this, the performance of local fluorescence intensity monitoring, which is also fully capable of reflecting the instant cell volume variations remains stable, independent of the system used and application.

Higher levels of matrix metalloproteinase-3 in patients with RA reflect disease activity and structural damage.

AIMS: To evaluate the serum levels of matrix metalloproteinase-3 (MMP-3) as a potential marker of disease activity and joint damage in 92 patients with rheumatoid arthritis (RA), compared to 24 osteoarthritis (OA) patients and 26 healthy controls. METHODS: The concentrations of MMP-3 were measured by ELISA using the commercial kit AESKULISA DF MMP-3 (AESKU.Diagnostics, Germany) and compared with other laboratory parameters routinely used to assess the disease status, clinical score (DAS28) and radiographic stage in the group of RA patients. RESULTS: The mean serum concentrations of MMP-3 were 199.1 ± 160 ng/mL in RA patients, 113.9 ± 96.9 ng/mL in OA patients and 48.3 ± 19.2 in healthy controls. The differences were highly significant: RA patients and healthy controls (P<0.0001), RA and OA patients (P=0.008) as well as between OA patients and controls (P=0.009). MMP-3 concentrations were further compared with other laboratory parameters and clinical and structural damage data. There were correlations between MMP-3 and CRP (r=0.304, P<0.01), DAS28 (r=0.301, P<0.05), levels of anti-cyclic citrullinated peptide antibodies (r=0.241, P<0.05), erythrocyte sedimentation rate (r=0.200, P=0.059) and radiographic disease stage (r=0.197, P=0.063). CONCLUSION: These results demonstrated that measurement of MMP-3 could become a marker of disease activity in RA patients.

High-contrast X-ray micro-radiography and micro-CT of ex-vivo soft tissue murine organs utilizing ethanol fixation and large area photon-counting detector.

Using dedicated contrast agents high-quality X-ray imaging of soft tissue structures with isotropic micrometre resolution has become feasible. This technique is frequently titled as virtual histology as it allows production of slices of tissue without destroying the sample. The use of contrast agents is, however, often an irreversible time-consuming procedure and despite the non-destructive principle of X-ray imaging, the sample is usually no longer usable for other research methods. In this work we present the application of recently developed large-area photon counting detector for high resolution X-ray micro-radiography and micro-tomography of whole ex-vivo ethanol-preserved mouse organs. The photon counting detectors provide dark-current-free quantum-counting operation enabling acquisition of data with virtually unlimited contrast-to-noise ratio (CNR). Thanks to the very high CNR even ethanol-only preserved soft-tissue samples without addition of any contrast agent can be visualized in great detail. As ethanol preservation is one of the standard steps of tissue fixation for histology, the presented method can open a way for widespread use of micro-CT with all its advantages for routine 3D non-destructive soft-tissue visualisation.

Prospective study of signalling pathways in myeloma bone disease with regard to activity of the disease, extent of skeletal involvement and correlation to bone turnover markers.

AIMS: The aim of our study was to address the utility of serum levels of selected parameters of myeloma bone disease (MBD) signalling with regard to the pathogenesis of multiple myeloma (MM), activity, markers of bone turnover and extent of skeletal changes. PATIENTS AND METHODS: We assessed prospectively 77 individuals with monoclonal gammopathies - 46 patients with active MM (AMM), 12 patients with smouldering MM (SMM) and 19 individuals with monoclonal gammopathy of undetermined significance (MGUS) to determine the role of HGF, MIP-1α, Syndecan-1, osteoprotegerin, Activin A, DKK1, Annexin A2 and NF-κB. RESULTS: We found significant differences of most of the parameters between MGUS and AMM, and with respect to the activity of MM assessed by International Staging System. Most of the parameters of MBD signalling correlated with traditional markers of bone turnover. CONCLUSIONS: All the signalling pathways were activated in MM with more pronounced osteoclastogenesis in comparison with bone formation but not in MGUS regardless of its risk category, suggesting that MBD is not activated in MGUS until the process of transformation into MM. The parameters of MBD signalling might precede the increase of conventional parameters of bone turnover suggesting their possible role in early indication of anti-resorption therapy.

[Ultrasound elastography and its use in the head and neck imaging]. / Ultrazvuková elastografie a její vyuzití v oblasti hlavy a krku.

Ultrasound elastography (sonoelastography, USE) is a relatively new, rapidly evolving area of imaging that measures elasticity of tissues. Its development started in the last decade of the 20th century and was accelerated after devices allowing real-time imaging and quantification (shear wave elastography, SWE) became broadly available for clinical practise. First results suggest that combination of sonoelastography and conventional ultrasound gives more precise results than ultrasound alone in certain areas. In head and neck imaging, just a few mostly pilot studies have been published till January 2014. This article summarizes available information about sonoelastography and current view on USE imaging in otorhinolaryngology.

Incomplete and accessory fissures of the lung evaluated by high-resolution computed tomography.

PURPOSE: The aim of our study was to assess incomplete and accessory interlobar fissures using volumetric thin-section high-resolution computed tomography (HRCT). MATERIALS AND METHODS: Retrospective assessment of HRCT examinations of 250 patients was performed. We assessed the localization, extension, and type of the incompleteness of fissures as well as the presence and localization of accessory fissures. We searched for possible correlation among the localization of interlobar fissures, the presence of incompleteness, and accessory fissures. RESULTS: On the left side, an incomplete oblique fissure was found in 24%. The discontinuity was present in the parahilar region and the area of the incompleteness was most frequently between 21% and 40%. The right oblique fissure was incomplete in 35%, mostly parahilarly, with the most frequent discontinuity below 20%. An incomplete horizontal fissure was found in 74%. Accessory fissures were identified in 16% of patients, with the same frequency on both sides. The most frequent finding was accessory horizontal fissure with 8.0% on the left side, superior accessory fissure (7.2%) and inferior accessory fissure (5.2%) on the right side. No correlation was found among the localization of interlobar fissures, the presence of incompleteness, and accessory fissures. CONCLUSION: Incomplete and accessory fissures are frequent anatomic variations of interlobar fissures.

Intima media thickness measurement as a marker of subclinical atherosclerosis in SLE patient.

AIM: Accelerated atherosclerosis in systemic lupus erythematosus (SLE) is an important cause of morbidity and mortality. The pathophysiology of accelerated atherosclerosis in SLE is mediated by factors such as inflammatory processes in the vascular wall, specific antibodies, dyslipoproteinemia, endothelial dysfunction and the high prevalence of traditional risk factors for cardiovascular diseases. In this context, we evaluated the clinical significance of ultrasound examination of the carotic arteries in the early diagnosis of atherosclerosis. METHODS: The study included 63 patients with SLE (female: male 53:10, mean age 38.4±12.7 years, mean disease duration 143.0±82.6 months), 24 patients had lupus nephritis. The control group consisted of 24 volunteers (female: male 20:4 mean age 31.04±8.59). Intima media thickness (IMT) was measured by ultrasound on both sides. The results were correlated with markers of lipid spectrum, anti-dsDNA, antinucleosomal and anticardiolipin antibodies, lupus anticoagulant and complement components. Clinical disease activity and damage were evaluated by SLEDAI and SLICC indices. Lifestyle and other important factors were examined per protocol and by questionnaire. RESULTS: A significant difference of IMT (P≤0.03) was found between the lupus patients and sex-age adjusted healthy controls with an in mean IMT in SLE patients of 0.569±0.11 mm, in control group 0.495±0.05 mm. A significant correlation between IMT and disease duration, age, positivity of lupus anticoagulant, use of ACE inhibitors, glomerular filtration and serum creatinine were found. No difference in IMT was found between patients with or without lupus nephritis. CONCLUSION: IMT measurement could be used as a clinical predictor of risk of accelerated atherosclerosis in lupus patients.

Complement system in SLE as a target for antibodies.

SLE is characterized by overproduction of various types of autoantibodies. Under certain circumstances, antibodies targeting some of the neoepitopes of the complement system can be seen. The most studied among antibodies directed against a component of the complement system is anti-C1q. Anti-C1q antibodies are present in approximately one third of the patients with lupus, who often have high clinical disease activity and in particular renal involvement. In the presence of high titers of anti-C1q antibodies also the levels of C1q and C3 and C4 components of the complement system are also usually low. The presence of the anti-C1q antibodies is not limited or specific just for SLE or lupus nephritis. For the first time, they were described in HUVS (Hypocomplementemic Urticarial Vasculitis Sydrome), later in Felty´s syndrome, rheumatoid vasculitis, hepatitis C, poststreptococcal glomerulonephritis or aging population.

Surface anatomy of the pulmonary fissures determined by high-resolution computed tomography.

The aim of our study was to describe the surface anatomy of the interlobar fissures using volumetric thin-section high-resolution computed tomography (HRCT). Retrospective assessment of HRCT examinations of 250 patients was performed. The localization of the oblique fissures was marked at three sites: posteriorly at its most superior medial limit, laterally in the midaxillary line, and inferiorly at the junction of the middle and lateral thirds of the hemithorax; posteriorly and laterally, this was to the nearest rib whilst inferiorly the position was described in relation to the diaphragm or chest wall. The localization of the horizontal fissure was marked anteriorly in relation to the nearest rib (or costal cartilage) and posteriorly where it intersected with the oblique fissure (superior, middle, or inferior third). Shapes of the fissures and differences between inspiration and expiration were also documented. Descriptive statistics were used to report the most frequent positions. The most frequent localization of the oblique fissure on the left side was posteriorly at the fourth rib (45%), laterally at the sixth rib (52%), and inferiorly in the anterior third of the hemidiaphragm (60%). The right oblique fissure was located posteriorly at the fifth rib (50%), laterally at the sixth rib (50%), and inferiorly in the anterior third of the hemidiaphragm (71%). The horizontal fissure most commonly originated in the middle third of the oblique fissure (61%) and met the anterior thoracic wall at the level of the fourth rib (51%). The most frequent shape of the left oblique fissure was linear (78%), whereas S-shaped and linear configurations (28% each) were most frequent on the right. No difference was found in the surface markings of the fissures between inspiration and expiration in 90% of cases. The considerable individual variation in the position and shape of the interlobar fissures helps to explain the variable descriptions of their surface anatomy in the literature.