Genetics of white color and iridophoroma in "Lemon Frost" leopard geckos.

The squamates (lizards and snakes) are close relatives of birds and mammals, with more than 10,000 described species that display extensive variation in a number of important biological traits, including coloration, venom production, and regeneration. Due to a lack of genomic tools, few genetic studies in squamates have been carried out. The leopard gecko, Eublepharis macularius, is a popular companion animal, and displays a variety of coloration patterns. We took advantage of a large breeding colony and used linkage analysis, synteny, and homozygosity mapping to investigate a spontaneous semi-dominant mutation, "Lemon Frost", that produces white coloration and causes skin tumors (iridophoroma). We localized the mutation to a single locus which contains a strong candidate gene, SPINT1, a tumor suppressor implicated in human skin cutaneous melanoma (SKCM) and over-proliferation of epithelial cells in mice and zebrafish. Our work establishes the leopard gecko as a tractable genetic system and suggests that a tumor suppressor in melanocytes in humans can also suppress tumor development in iridophores in lizards.

Fractional myocardial blood volume by ferumoxytol-enhanced MRI: Estimation of ischemic burden.

PURPOSE: To investigate model-fitted fractional myocardial blood volume (fMBV) derived from ferumoxytol-enhanced MRI as a measure of myocardial tissue hypoperfusion at rest. METHODS: We artificially induced moderate to severe focal coronary stenosis in the left anterior descending artery of 19 swine by percutaneous delivery of a 3D-printed coronary implant. Using the MOLLI pulse sequence, we acquired T1 maps at 3 T after multiple incremental ferumoxytol doses (0.0-4.0 mg/kg). We computed pixel-wise fMBV using a multi-compartmental modeling approach in 19 ischemic swine and 4 healthy swine. RESULTS: Ischemic myocardial segments showed a mean MRI-fMBV of 11.72 ± 3.00%, compared with 8.23 ± 2.12% in remote segments and 8.38 ± 2.23% in normal segments. Ischemic segments showed a restricted transvascular water-exchange rate (ki  = 15.32 ± 8.69 s-1 ) relative to remote segments (ki  = 17.78 [11.60, 26.36] s-1 ). A mixed-effects model found significant difference in fMBV (p = 0.002) and water-exchange rate (p < 0.001) between ischemic and remote myocardial regions after adjusting for biological sex and slice location. Analysis of fMBV as a predictor of impaired myocardial contractility using receiver operating characteristics showed an area under the curve of 0.89 (95% confidence interval [CI] 0.80, 0.95). An MRI-fMBV threshold of 9.60% has a specificity of 90.0% (95% CI 76.3, 97.2) and a sensitivity of 72.5% (95% CI 56.1, 83.4) for prediction of impaired myocardial contractility. CONCLUSIONS: Model-fitted fMBV derived from ferumoxytol-enhanced MRI can distinguish regions of ischemia from remote myocardium in a swine model of myocardial hypoperfusion.

Applicability of rat precision-cut lung slices in evaluating nanomaterial cytotoxicity, apoptosis, oxidative stress, and inflammation.

The applicability of rat precision-cut lung slices (PCLuS) in detecting nanomaterial (NM) toxicity to the respiratory tract was investigated evaluating sixteen OECD reference NMs (TiO2, ZnO, CeO2, SiO2, Ag, multi-walled carbon nanotubes (MWCNTs)). Upon 24-hour test substance exposure, the PCLuS system was able to detect early events of NM toxicity: total protein, reduction in mitochondrial activity, caspase-3/-7 activation, glutathione depletion/increase, cytokine induction, and histopathological evaluation. Ion shedding NMS (ZnO and Ag) induced severe tissue destruction detected by the loss of total protein. Two anatase TiO2 NMs, CeO2 NMs, and two MWCNT caused significant (determined by trend analysis) cytotoxicity in the WST-1 assay. At non-cytotoxic concentrations, different TiO2 NMs and one MWCNT increased GSH levels, presumably a defense response to reactive oxygen species, and these substances further induced a variety of cytokines. One of the SiO2 NMs increased caspase-3/-7 activities at non-cytotoxic levels, and one rutile TiO2 only induced cytokines. Investigating these effects is, however, not sufficient to predict apical effects found in vivo. Reproducibility of test substance measurements was not fully satisfactory, especially in the GSH and cytokine assays. Effects were frequently observed in negative controls pointing to tissue slice vulnerability even though prepared and handled with utmost care. Comparisons of the effects observed in the PCLuS to in vivo effects reveal some concordances for the metal oxide NMs, but less so for the MWCNT. The highest effective dosages, however, exceeded those reported for rat short-term inhalation studies. To become applicable for NM testing, the PCLuS system requires test protocol optimization.

Neonatal blue light phototherapy increases café-au-lait macules in preschool children.

UNLABELLED: Neonatal blue light phototherapy (NBLP) is an effective treatment for hyperbilirubinaemia. Concerning the influence on melanocytic nevi, conflicting studies have been published. To assess the role of NBLP according to the incidence of melanocytic nevi in preschool children, a cohort of 104 5- to 6-year-old children were included. The case group consisted of 52 NBLP-exposed children, while the control group (n = 52) never had NBLP and was matched regarding age, gender, gestational age and skin phototype. Six dizygotic twins were included with one twin having received NBLP, respectively. The following parameters were recorded: nevi count, presence of freckles, café-au-lait macules, skin phototype and previous history of sun exposure. There was no significant association between nevi count and exposure to NBLP (median nevi count 17.0 compared to 18.5 in controls). No significant difference was also found in the dizygotic twin pairs with a median nevi count of 10.0 (with NBLP) compared to 14.5 (without NBLP). However, a significantly higher prevalence of café-au-lait macules was found in children with NBLP (mean count 0.5) than in children without NBLP (mean count 0.2; p = 0.001). Significant predictors for the number of melanocytic nevi included skin phototype, sun exposure and vacations in the South. CONCLUSION: In this study, NBLP had no significant influence on the development of melanocytic nevi, but on café-au-lait macules which was a new finding. Differences with comparable studies regarding age, differentiation between nevi and other pigmented lesions as well as dose and type of NBLP need to be taken into account for further investigations.

The use of eutectic mixture of lidocaine and prilocaine in mice (Mus musculus) for tail vein injections.

OBJECTIVE: To investigate a topical local anesthesia technique as a means to prevent and/or diminish pain in mice in a laboratory setting associated with tail vein injections performed by personnel in training. STUDY DESIGN: Prospective, randomized experimental trial. ANIMALS: Thirty six adult female, 23-28 g CD-1 mice from an in-house training colony. They were acclimated to routine training and handling classes. METHODS: Eutectic mixture of local anesthetics (EMLA) cream (2.5% lidocaine/2.5% prilocaine) or a bland ointment control (n = 18) was applied on the tail prior to intravenous injection. The injections were performed by novices, who had never attempted the procedure, and experienced personnel. All participants were blinded to treatment groups. Three injection attempts were allowed per animal. The mice were observed and scored by blinded evaluators for behavioral and physiological changes, including respiratory rate, vocalization, tail flick, and escape behaviors, during and after the injection. RESULTS: This study demonstrates that aversive behaviors induced by lateral tail vein injection were not changed by the preemptive application of EMLA cream. The aversive behaviors associated with lateral tail vein injection were significantly affected by the number of injection attempts and the individual's experience level. CONCLUSIONS AND CLINICAL RELEVANCE: Topical EMLA cream did not reduce signs of aversive reaction to tail vein injection and thus we did not find support for its use in mouse training programs for tail vein injections.

Machine learning-directed electrical impedance tomography to predict metabolically vulnerable plaques.

The characterization of atherosclerotic plaques to predict their vulnerability to rupture remains a diagnostic challenge. Despite existing imaging modalities, none have proven their abilities to identify metabolically active oxidized low-density lipoprotein (oxLDL), a marker of plaque vulnerability. To this end, we developed a machine learning-directed electrochemical impedance spectroscopy (EIS) platform to analyze oxLDL-rich plaques, with immunohistology serving as the ground truth. We fabricated the EIS sensor by affixing a six-point microelectrode configuration onto a silicone balloon catheter and electroplating the surface with platinum black (PtB) to improve the charge transfer efficiency at the electrochemical interface. To demonstrate clinical translation, we deployed the EIS sensor to the coronary arteries of an explanted human heart from a patient undergoing heart transplant and interrogated the atherosclerotic lesions to reconstruct the 3D EIS profiles of oxLDL-rich atherosclerotic plaques in both right coronary and left descending coronary arteries. To establish effective generalization of our methods, we repeated the reconstruction and training process on the common carotid arteries of an unembalmed human cadaver specimen. Our findings indicated that our DenseNet model achieves the most reliable predictions for metabolically vulnerable plaque, yielding an accuracy of 92.59% after 100 epochs of training.

Cytosolic Bax: does it require binding proteins to keep its pro-apoptotic activity in check?

Bax is kept inactive in the cytosol by refolding its C-terminal transmembrane domain into the hydrophobic binding pocket. Although energetic calculations predicted this conformation to be stable, numerous Bax binding proteins were reported and suggested to further stabilize inactive Bax. Unfortunately, most of them have not been validated in a physiological context on the endogenous level. Here we use gel filtration analysis of the cytosol of primary and established cells to show that endogenous, inactive Bax runs 20-30 kDa higher than recombinant Bax, suggesting Bax dimerization or the binding of a small protein. Dimerization was excluded by a lack of interaction of differentially tagged Bax proteins and by comparing the sizes of dimerized recombinant Bax with cytosolic Bax on blue native gels. Surprisingly, when analyzing cytosolic Bax complexes by high sensitivity mass spectrometry after anti-Bax immunoprecipitation or consecutive purification by gel filtration and blue native gel electrophoresis, we detected only one protein, called p23 hsp90 co-chaperone, which consistently and specifically co-purified with Bax. However, this protein could not be validated as a crucial inhibitory Bax binding partner as its over- or underexpression did not show any apoptosis defects. By contrast, cytosolic Bax exhibits a slight molecular mass shift on SDS-PAGE as compared with recombinant Bax, which suggests a posttranslational modification and/or a structural difference between the two proteins. We propose that in most healthy cells, cytosolic endogenous Bax is a monomeric protein that does not necessarily need a binding partner to keep its pro-apoptotic activity in check.

Patch testing for noncontact dermatitis: the atopy patch test for food and inhalants.

The atopy patch test (APT) is defined as a patch test procedure to assess delayed type hypersensitivity reactions against those protein allergens known to elicit IgE-mediated type I reactions in atopic patients. This patch test procedure uses intact protein allergens instead of haptens in an optimized test setting and with a special reading key. It may be clinically useful especially for atopic dermatitis, as the currently available test procedures either target the wrong reaction type (type I and not type IV) or use the wrong allergens (haptens and not protein allergen). A positive APT reaction correlates with a positive lymphocyte transformation test and allergen-specific Th2 cells in the peripheral blood. As even small changes in the test procedure influence the sensitivity, specificity, and reproducibility of the APT, the European Task Force on Atopic Dermatitis (ETFAD) has developed a standardized APT technique: Intact protein allergens, purified in petrolatum, are applied in 12-mm-diameter Finn chambers mounted on Scanpor tape for 48 h to non-irritated, non-abraded, or tape-stripped skin of the upper back for 48 h; the evaluation of the test reaction is done after 48 and 72 h using the ETFAD reading key, assessing erythema as well as number and distribution pattern of the papules. The APT may reveal type IV sensitization in patients who are negative for the respective type I tests. Limited availability of the expensive test substances and limited reimbursement is among the factors restricting the routine use of the APT.

Unilateral favre-racouchot disease: evidence for the etiological role of chronic solar damage.

Favre-Racouchot disease commonly presents as comedones, cysts and elastosis in the periocular region of older men. Its etiology has been linked to several exogenous factors. Here we present 2 patients with strictly unilateral manifestation of the disease and a corresponding history of predominantly one-sided chronic occupational sun exposure and smoking, making the case for the causative role of these two factors.

The epithelium specific cell cycle regulator 14-3-3sigma is required for preventing entry into mitosis following ultraviolet B.

BACKGROUND: Deoxyribonucleic acid damage activates cell cycle checkpoints in order to maintain genomic stability. We assessed the role of different checkpoint genes in response to ultraviolet B irradiation. METHODS: Cell lines expressing a dominant negative mutant of ataxia telangiectasia and Rad3 related (Atr) protein or overexpressing Cdc25A, cells deficient for 14-3-3σ, Nijmegen breakage syndrome (Nbs), or Ataxia telangiectasia mutated (Atm) were treated with ultraviolet B (UVB) and harvested after 12 h, 24 h, or 48 h for analysis by flow cytometry. RESULTS: Functional loss of Atm, Atr, or Nbs did not result in a significant alteration of the cell cycle profile. Overexpression of Cdc25A led to a delayed arrest at the G1/S transition in response to low doses of UVB. Loss of 14-3-3σ, a negative cell cycle regulator and downstream target of p53, caused a transient arrest at the G2/M boundary. CONCLUSIONS: Loss of 14-3-3σ sensitizes cells to UVB. After a transient cell cycle arrest, 14-3-3σ-deficient cells die by undergoing mitotic catastrophe. Cdc25A overexpression causes a delayed arrest in response to low doses of UVB. After higher doses, Cdc25A is no longer able to overrun the checkpoint. Atm, Atr, or Nbs are not essential for the checkpoint response to UVB, suggesting the existence of redundant signaling pathways.

Myeloid progenitor cells lacking p53 exhibit delayed up-regulation of Puma and prolonged survival after cytokine deprivation.

Loss of p53-dependent apoptosis contributes to the development of hematologic malignancies and failure to respond to treatment. Proapoptotic Bcl-2 family member Puma is essential for apoptosis in HoxB8-immortalized interleukin-3 (IL-3)-dependent myeloid cell lines (FDM cells) provoked by IL-3 deprivation. p53 and FoxO3a can transcriptionally regulate Puma. To investigate which transcriptional regulator is responsible for IL-3 deprivation-induced Puma expression and apoptosis, we generated wild-type (WT), p53(-/-), and FoxO3a(-/-) FDM cells and found that p53(-/-) but not FoxO3a(-/-) cells were protected against IL-3 withdrawal. Loss of p21(cip/waf), which is critical for p53-mediated cell-cycle arrest, afforded no protection against IL-3 deprivation. A survival advantage was also observed in untransformed p53(-/-) hematopoietic progenitor cells cultured in the presence or absence of cytokines. In response to IL-3 deprivation, increased Puma protein levels in p53(-/-) cells were substantially delayed compared with WT cells. Increased p53 transcriptional activity was detected after cytokine deprivation. This was substantially less than that induced by DNA damage and associated not with increased p53 protein levels but with loss of the p53 regulator, MDM2. Thus, we conclude that p53 protein is activated after IL-3 deprivation by loss of MDM2. Activated p53 transcriptionally up-regulates Puma, which initiates apoptosis.

The Munich outbreak of cutaneous cowpox infection: transmission by infected pet rats.

Cowpox virus infection of humans is an uncommon, potentially fatal, skin disease. It is largely confined to Europe, but is not found in Eire, or in the USA, Australasia, or the Middle or Far East. Patients having contact with infected cows, cats, or small rodents sporadically contract the disease from these animals. We report here clinical aspects of 8 patients from the Munich area who had purchased infected pet rats from a local supplier. Pet rats are a novel potential source of local outbreaks. The morphologically distinctive skin lesions are mostly restricted to the patients' necks, reflecting the infected animals' contact pattern. Individual lesions vaguely resemble orf or Milker's nodule, but show marked surrounding erythema, firm induration and local adenopathy. Older lesions develop eschar, leaving slow-healing, deep ulcerative defects after eschar separation. Severe flu-like illness may be present in the acute phase. Smallpox-vaccinated patients tend to develop less severe reactions and heal more quickly. The differential diagnosis may include other localized orthopoxvirus infections, herpes simplex, bacterial infection, anthrax, foreign body granuloma, and primary tuberculosis. Dermatologists should be aware of the diagnostic and therapeutic algorithms for handling this disease.

Reducing retraction forces with tactile feedback during robotic total mesorectal excision in a porcine model.

Excessive tissue-instrument interaction forces during robotic surgery have the potential for causing iatrogenic tissue damages. The current in vivo study seeks to assess whether tactile feedback could reduce intraoperative tissue-instrument interaction forces during robotic-assisted total mesorectal excision. Five subjects, including three experts and two novices, used the da Vinci robot to perform total mesorectum excision in four pigs. The grip force in the left arm, used for retraction, and the pushing force in the right arm, used for blunt pelvic dissection around the rectum, were recorded. Tissue-instrument interaction forces were compared between trials done with and without tactile feedback. The mean force exerted on the tissue was consistently higher in the retracting arm than the dissecting arm (3.72 ± 1.19 vs 0.32 ± 0.36 N, p < 0.01). Tactile feedback brought about significant reductions in average retraction forces (3.69 ± 1.08 N vs 4.16 ± 1.12 N, p = 0.02), but dissection forces appeared unaffected (0.43 ± 0.42 vs 0.37 ± 0.28 N, p = 0.71). No significant differences were found between retraction and dissection forces exerted by novice and expert robotic surgeons. This in vivo animal study demonstrated the efficacy of tactile feedback in reducing retraction forces during total mesorectal excision. Further research is required to quantify the clinical impact of such force reduction.

[Continuous patient survey as an instrument to improve patient satisfaction: the relevance of nurses within the process of quality judgement]. / Kontinuierliche Patientenbefragung als Instrument zur Verbesserung der Patientenzufriedenheit. Bedeutung der Pflegenden im Prozess der Qualitätsbeurteilung.

The satisfaction of patients with their hospital stay as well as their willingness to recommend the clinic to friends and relatives are important parameters for a hospital's success. To achieve ascertained indications for necessary improvements concerning the quality of care, HELIOS Hospital Group has established a continuous patient survey. Similar to their medical quality management system, HELIOS puts high emphasize on transparency and benchmarks in order to initiate improvement processes. A critical analysis and close look especially on bad feedbacks of patients regarding their hospital stay allows each hospital, department or ward to monthly identify major drivers for critical responses and suggests opportunities for improvement. In the first six months of 2009 64.741 questionaries were returned. Having analyzed them the patient survey showed, that nurses and medical doctors had a special influence on the patient's satisfaction and dissatisfaction with the hospital.

In Vivo Intravascular Pacing Using a Wireless Microscale Stimulator.

Millions of patients worldwide are implanted with permanent pacemakers for the treatment of cardiac arrhythmias and conduction disorders. The increased use of these devices has established a growing clinical need to mitigate associated complications. Pacemaker leads, in particular, present the primary risks in most implants. While wireless power transfer holds great promise in eliminating implantable device leads, anatomical constraints limit efficient wireless transmission over the necessary operational range. We thereby developed a transmitter-centered control system for wireless power transfer with sufficient power for continuous cardiac pacing. Device safety was validated using a computational model of the system within an MRI-based anatomical model. The pacer was then fabricated to meet the acute constraints of the anterior cardiac vein (ACV) to enable intravascular deployment while maintaining power efficiency. Our computational model revealed the wireless system to operate at > 50 times below the tissue energy absorption safety criteria. We further demonstrated the capacity for ex vivo pacing of pig hearts at 60 beats per minute (BPM) and in vivo pacing at 120 BPM following pacer deployment in the ACV. This work thus established the capacity for wireless intravascular pacing with the potential to eliminate complications associated with current lead-based deep tissue implants.

Real-time 3T MRI-guided cardiovascular catheterization in a porcine model using a glass-fiber epoxy-based guidewire.

PURPOSE: Real-time magnetic resonance imaging (MRI) is a promising alternative to X-ray fluoroscopy for guiding cardiovascular catheterization procedures. Major challenges, however, include the lack of guidewires that are compatible with the MRI environment, not susceptible to radiofrequency-induced heating, and reliably visualized. Preclinical evaluation of new guidewire designs has been conducted at 1.5T. Here we further evaluate the safety (device heating), device visualization, and procedural feasibility of 3T MRI-guided cardiovascular catheterization using a novel MRI-visible glass-fiber epoxy-based guidewire in phantoms and porcine models. METHODS: To evaluate device safety, guidewire tip heating (GTH) was measured in phantom experiments with different combinations of catheters and guidewires. In vivo cardiovascular catheterization procedures were performed in both healthy (N = 5) and infarcted (N = 5) porcine models under real-time 3T MRI guidance using a glass-fiber epoxy-based guidewire. The times for each procedural step were recorded separately. Guidewire visualization was assessed by measuring the dimensions of the guidewire-induced signal void and contrast-to-noise ratio (CNR) between the guidewire tip signal void and the blood signal in real-time gradient-echo MRI (specific absorption rate [SAR] = 0.04 W/kg). RESULTS: In the phantom experiments, GTH did not exceed 0.35°C when using the real-time gradient-echo sequence (SAR = 0.04 W/kg), demonstrating the safety of the glass-fiber epoxy-based guidewire at 3T. The catheter was successfully placed in the left ventricle (LV) under real-time MRI for all five healthy subjects and three out of five infarcted subjects. Signal void dimensions and CNR values showed consistent visualization of the glass-fiber epoxy-based guidewire in real-time MRI. The average time (minutes:seconds) for the catheterization procedure in all subjects was 4:32, although the procedure time varied depending on the subject's specific anatomy (standard deviation = 4:41). CONCLUSIONS: Real-time 3T MRI-guided cardiovascular catheterization using a new MRI-visible glass-fiber epoxy-based guidewire is feasible in terms of visualization and guidewire navigation, and safe in terms of radiofrequency-induced guidewire tip heating.

3D-Printed Coronary Implants Are Effective for Percutaneous Creation of Swine Models with Focal Coronary Stenosis.

Reliable, closed-chest methods for creating large animal models of acute myocardial hypoperfusion are limited. We demonstrated the feasibility and efficacy of using magnetic resonance (MR)-compatible 3D-printed coronary implants for establishing swine models of myocardial hypoperfusion. We designed, manufactured, and percutaneously deployed implants in 13 swine to selectively create focal coronary stenosis. To test the efficacy of the implants to cause hypoperfusion or ischemia in the perfused territory, we evaluated regional wall motion, myocardial perfusion, and infarction using MR imaging. The overall swine survival rate was 85% (11 of 13). The implant retrieval rate was 92% (12 of 13). Fluoroscopic angiography confirmed focal stenosis. Cine and perfusion MRI showed regional wall motion abnormalities and inducible ischemia, respectively. Late gadolinium enhancement and histopathology showed no myocardial infarction. Our minimally invasive technique has promising applications for validation of new diagnostic methods in cardiac MR. Graphical abstract Our new minimally invasive, percutaneous method for creating swine models of acute focal coronary stenosis can be used for magnetic resonance imaging studies of myocardial ischemia. Comparable to existing methods in its efficacy and reliability, this rapid prototyping technique will allow researchers to more easily conduct translational cardiac imaging studies of coronary artery disease in large animal models.

Switch from type II to I Fas/CD95 death signaling on in vitro culturing of primary hepatocytes.

UNLABELLED: Fas/CD95-induced apoptosis of hepatocytes in vivo proceeds through the so-called type II pathway, requiring the proapoptotic BH3-only Bcl-2 family member Bid for mitochondrial death signaling. Consequently, Bid-deficient mice are protected from anti-Fas antibody injection induced fatal hepatitis. We report the unexpected finding that freshly isolated mouse hepatocytes, cultured on collagen or Matrigel, become independent of Bid for Fas-induced apoptosis, thereby switching death signaling from type II to type I. In such in vitro cultures, Fas ligand (FasL) activates caspase-3 without Bid cleavage, Bax/Bak activation or cytochrome c release, and neither Bid ablation nor Bcl-2 overexpression is protective. The type II to type I switch depends on extracellular matrix adhesion, as primary hepatocytes in suspension die in a Bid-dependent manner. Moreover, the switch is specific for FasL-induced apoptosis as collagen-plated Bid-deficient hepatocytes are protected from tumor necrosis factor alpha/actinomycin D (TNFalpha/ActD)-induced apoptosis. CONCLUSION: Our data suggest a selective crosstalk between extracellular matrix and Fas-mediated signaling that favors mitochondria-independent type I apoptosis induction.

Selective middle cerebral artery occlusion in the rabbit: Technique and characterization with pathologic findings and multimodal MRI.

BACKGROUND: A reliable animal model of ischemic stroke is vital for pre-clinical evaluation of stroke therapies. We describe a reproducible middle cerebral artery (MCA) embolic occlusion in the French Lop rabbit characterized with multimodal MRI and histopathologic tissue analysis. NEW METHOD: Fluoroscopic-guided microcatheter placement was performed in five consecutive subjects with angiographic confirmation of MCA occlusion with autologous clot. Multimodal MRI was obtained prior to occlusion and up to six hours post after which repeat angiography confirmed sustained occlusion. The brain was harvested for histopathologic examination. RESULTS: Angiography confirmed successful MCA catheterization and durable (>6 h) MCA occlusion in all animals. There was increase of ADC volume over time and variable final core volume presumably related to individual variation in collateral flow. FLAIR hyperintensity indicative of cytotoxic edema and parenchymal contrast enhancement reflective of blood brain barrier disruption was observed over time. Tissue staining of the ischemic brain showed edema and structural alterations consistent with infarction. COMPARISON WITH EXISTING METHODS: This study describes a technique of selective catheterization and embolic occlusion of the MCA in the rabbit with MRI characterization of evolution of ischemia in the model. CONCLUSIONS: We demonstrate the feasibility of a rabbit model of embolic MCA occlusion with angiographic documentation. Serial MR imaging demonstrated changes comparable to those observed in human ischemic stroke, confirmed histopathologically.

Preprotein transport machineries of yeast mitochondrial outer membrane are not required for Bax-induced release of intermembrane space proteins.

The mitochondrial outer membrane contains protein import machineries, the translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). It has been speculated that TOM or SAM are required for Bax-induced release of intermembrane space (IMS) proteins; however, experimental evidence has been scarce. We used isolated yeast mitochondria as a model system and report that Bax promoted an efficient release of soluble IMS proteins while preproteins were still imported, excluding an unspecific damage of mitochondria. Removal of import receptors by protease treatment did not inhibit the release of IMS proteins by Bax. Yeast mutants of each Tom receptor and the Tom40 channel were not impaired in Bax-induced protein release. We analyzed a large collection of mutants of mitochondrial outer membrane proteins, including SAM, fusion and fission components, but none of these components was required for Bax-induced protein release. The released proteins included complexes up to a size of 230 kDa. We conclude that Bax promotes efficient release of IMS proteins through the outer membrane of yeast mitochondria while the inner membrane remains intact. Inactivation of the known protein import and sorting machineries of the outer membrane does not impair the function of Bax at the mitochondria.