[Nonthrombotic pulmonary embolisms]. / Nichtthrombotische Lungenembolien.

The term nonthrombotic pulmonary embolism (NTPE) is defined as embolization of pulmonary arteries caused by foreign bodies (e. g. detached catheter fragments), biological substances (e. g. septic thrombus) or exogenous substances (e. g. gas). The frequency of NTPE is underestimated. Symptoms can cover the spectrum from undetectable to sudden death. In addition to mechanical obstruction of the pulmonary arteries, some NTPEs trigger an inflammatory cascade that causes deterioration of vascular, pulmonary and cardiac function. Radiological imaging in combination with the medical history of patients is sufficient to identify most NTPEs with certainty. The aim of this article is to make readers aware of the symptoms, frequency, relevance, classification, pathophysiology, laboratory findings and radiological findings of the most frequent forms of NTPE. The spectrum of forms presented here includes pulmonary embolisms due to foreign bodies (intravascular, intracorporeal and extracorporeal), amniotic fluid, endogenous tissue, fat, tumors, septic thrombi, hydatids, cement, metallic mercury, gas, silicone and particles.

[Clinically relevant incidental cardiovascular findings in CT examinations]. / Klinisch relevante kardiovaskuläre Zufallsbefunde bei CT­Untersuchungen.

BACKGROUND AND METHOD: Incidental cardiovascular findings are a frequent phenomenon in computed tomography (CT) examinations. As the result of a dedicated PubMed search this article gives a systemic overview of the current literature on the most important incidental cardiovascular findings, their prevalence and clinical relevance. RESULTS: The majority of incidental cardiovascular findings are of only low clinical relevance; however, highly relevant incidental findings, such as aortic aneurysms, thromboses and thromboembolic events can also occasionally be found, especially in oncology patients. CONCLUSION: The scans from every CT examination should also be investigated for incidental findings as they can be of decisive importance for the further clinical management of patients, depending on their clinical relevance.

Proximie in the operating theatre: evaluation of a virtual operating platform for medical student education.

INTRODUCTION: Medical students often hesitate to enter the operating theatre because of poor visibility of the surgical field and anxiety about the theatre environment. In addition, ear, nose and throat (ENT) surgery is underrepresented in many medical curricula. Virtual systems like Proximie offer flexible viewing of surgeries with surgeon commentary, potentially addressing these issues. METHODS: This descriptive survey study aimed to evaluate the use of Proximie as a surgical education tool for delivering ENT teaching to medical students. Live ENT procedures were recorded at the ENT Department of the John Radcliffe Hospital and shared with interested clinical medical students through Proximie accounts. Students were added to a private group chat to ask questions and provided feedback through structured forms, assessing procedural effectiveness and the platform's technology. Live-streaming and recording of procedures were facilitated by ENT surgeons providing commentary. RESULTS: Conducted over four virtual theatre days, the study gathered 52 responses: 96% of students rated Proximie's educational value as 4 of 5 or higher; 57% preferred the virtual experience over physical attendance because of its convenience and the improved view of the surgical field. Students valued the live commentary and showed interest in using Proximie for a broader range of surgeries. Suggested improvements included fixing technical issues, better communication of theatre lists, and expanding surgical specialty coverage. CONCLUSIONS: Proximie has been highly rated by medical students for its effective and engaging approach in the instruction of surgical skills, underscoring its value as an educational tool. Future research is needed to formally assess knowledge acquisition and retention across multiple surgical subspecialties. This work is the first step towards evaluating the utility of virtual operating theatre platforms for medical student education.

Influence of intragenic CCL3 haplotypes and CCL3L copy number in HIV-1 infection in a sub-Saharan African population.

Two CCL3 haplotypes (HapA1 and Hap-A3) and two polymorphic positions shared by the haplotypes (Hap-2SNP (single nucleotide polymorphism)) were investigated together with CCL3L copy number (CN), for their role in HIV-1 disease. Hap-A1 was associated with protection from in utero HIV-1 infection: exposed uninfected (EU) infants had higher representation of wild type (WT)/Hap-A1 than infected infants (excluding intrapartum (IP)-infected infants), which maintained significance post maternal Nevirapine (mNVP) and viral load (MVL) correction (P=0.04; odds ratio (OR)=0.33). Mother-infant pair analyses showed the protective effect of Hap-A1 is dependent on its presence in the infant. Hap-A3 was associated with increased IP transmission: WT/Hap-A3 was increased in IP-transmitting vs non-transmitting (NT) mothers, and remained significant post mNVP and MVL correction (P=0.02; OR=3.50). This deleterious effect of Hap-A3 seemed dependent on its presence in the mother. Hap-2SNP was associated with lower CD4 count in the NT mothers (P=0.03). CCL3 Hap-A1 was associated with high CCL3L CN in total (P=0.001) and EU infants (P=0.006); the effect was not additive, however, having either Hap-A1 or high CCL3L CN was more significantly (P=0.0008) associated with protection from in utero infection than Hap-A1 (P=0.028) or high CCL3L CN (P=0.002) alone. Linkage disequilibrium between Hap-A1 and high CCL3L CN appears unlikely given that a Nigerian population showed an opposite relationship.

Fatigue Life Modelling of Steel Suspension Coil Springs Based on Wavelet Vibration Features Using Neuro-Fuzzy Methods.

This study proposed wavelet-based approaches to characterise random vibration road excitations for durability prediction of coil springs. Conventional strain-life approaches require long computational time, while the accuracy of the vibration fatigue methods is unsatisfactory. It is therefore a necessity to establish an accurate fatigue life prediction model based on vibrational features. Wavelet-based methods were applied to determine the low-frequency energy and multifractality of road excitations. Strain-life models were applied for fatigue life evaluation from strain histories. ANFIS modelling was subsequently adopted to associate the vibration features with the fatigue life of coil springs. Results showed that the proposed wavelet-based methods were effective to determine the signal energy and multifractality of vibration signals. The established vibration-based models showed good fatigue life conservativity with a data survivability of more than 90%. The highest Pearson coefficient of 0.955 associated with the lowest RMSE of 0.660 was obtained by the Morrow-based model. It is suggested that the low-frequency energy and multifractality of the vibration signals can be used as fatigue-related features in life predictions of coil springs under random loading. Finally, the proposed model is an acceptable fatigue life prediction method based on vibration features, and it can reduce the dependency on strain data measurement.

Development of hemodynamically relevant acquired arterio-venous fistulae in patients with venous malformations.

BACKGROUND: Venous malformations tend to retain their slow-flow behavior, even in progressive disease or regression following therapy. OBJECTIVE: The aim of this study is to analyze the development of acquired hemodynamic relevant arterio-venous fistulae in patients with slow-flow malformations. METHODS: This study is a retrospective analysis based on a consecutive local registry at a tertiary care Interdisciplinary Center for Vascular Anomalies. Patients with venous malformations and development of secondary arterio-venous fistulae were included. Indications for therapy of the vascular malformation were based on patients' symptoms and complications. The following endpoints were of clinical interest and were assessed: origin of development of arteriovenous fistula, development of secondary comorbidities as a result of the vascular malformation. For analysis we focused on descriptive statistics. RESULTS: Out of 1213 consecutive patients with vascular malformations, in 6 patients perfusion changed from slow flow to arterio-venous fast-flow patterns. Four patients developed the fistula after local trauma in the area of the malformation, the other 2 patients developed the fistula due to progression of the disease and recurrent thrombophlebitis. These 2 patients had no trauma or interventions at the time of arterio-venous fistula development. CONCLUSIONS: Acquired arterio-venous fast-flow fistula in patients with slow flow vascular malformation is very rare and might be a result of local trauma or the progression of the disease with recurrent thrombophlebitis. Specific evidence-based treatment options for these patients do not exist.

Fractals and cosmological large-scale structure.

Observations of galaxy-galaxy and cluster-cluster correlations as well as other large-scale structure can be fit with a "limited" fractal with dimension D approximately 1.2. This is not a "pure" fractal out to the horizon: the distribution shifts from power law to random behavior at some large scale. If the observed patterns and structures are formed through an aggregation growth process, the fractal dimension D can serve as an interesting constraint on the properties of the stochastic motion responsible for limiting the fractal structure. In particular, it is found that the observed fractal should have grown from two-dimensional sheetlike objects such as pancakes, domain walls, or string wakes. This result is generic and does not depend on the details of the growth process.

Big-bang nucleosynthesis and the baryon density of the universe.

For almost 30 years, the predictions of big-bang nucleosynthesis have been used to test the big-bang model to within a fraction of a second of the bang. The agreement between the predicted and observed abundances of deuterium, helium-3, helium-4, and lithium-7 confirms the standard cosmology model and allows accurate determination of the baryon density, between 1.7 x 10(-31) and 4.1 x 10(-31) grams per cubic centimeter (corresponding to about 1 to 15 percent of the critical density). This measurement of the density of ordinary matter is pivotal to the establishment of two dark-matter problems: (i) most of the baryons are dark, and (ii) if the total mass density is greater than about 15 percent of the critical density, as many determinations indicate, the bulk of the dark matter must be "non-baryonic," composed of elementary particles left from the earliest moments.

Chocolate procyanidins decrease the leukotriene-prostacyclin ratio in humans and human aortic endothelial cells.

BACKGROUND: Polyphenolic phytochemicals inhibit vascular and inflammatory processes that contribute to disease. These effects are hypothesized to result from polyphenol-mediated alterations in cellular eicosanoid synthesis. OBJECTIVE: The objective was to determine and compare the ability of cocoa procyanidins to alter eicosanoid synthesis in human subjects and cultured human aortic endothelial cells. DESIGN: After an overnight fast, 10 healthy subjects (4 men and 6 women) consumed 37 g low-procyanidin (0.09 mg/g) and high-procyanidin (4.0 mg/g) chocolate; the treatments were separated by 1 wk. The investigation had a randomized, blinded, crossover design. Plasma samples were collected before treatment and 2 and 6 h after treatment. Eicosanoids were quantitated by enzyme immunoassay. Endothelial cells were treated in vitro with procyanidins to determine whether the effects of procyanidin in vivo were associated with procyanidin-induced alterations in endothelial cell eicosanoid synthesis. RESULTS: Relative to the effects of the low-procyanidin chocolate, high-procyanidin chocolate induced increases in plasma prostacyclin (32%; P<0.05) and decreases in plasma leukotrienes (29%; P<0.04). After the in vitro procyanidin treatments, aortic endothelial cells synthesized twice as much 6-keto-prostaglandin F(1alpha) (P<0.01) and 16% less leukotriene (P<0.05) as did control cells. The in vitro and in vivo effects of procyanidins on plasma leukotriene-prostacyclin ratios in culture medium were also comparable: decreases of 58% and 52%, respectively. CONCLUSION: Data from this short-term investigation support the concept that certain food-derived flavonoids can favorably alter eicosanoid synthesis in humans, providing a plausible hypothesis for a mechanism by which they can decrease platelet activation in humans.

New approach in the therapy of chronic rejection? ACE- and AT1-blocker reduce the development of chronic rejection after cardiac transplantation in a rat model.

BACKGROUND: Angiotensin II is one of the most potent mitogens of smooth muscle cell proliferation and plays a central role in the development of accelerated coronary artery disease (ACAD), which remains a serious consequence after heart transplantation and limits long-term survival. We investigated the effect of an angiotensin-II blocker, Losartan (angiotensin II Type 1 [AT(1)]-blocker), and an angiotensin-converting enzyme (ACE) inhibitor, Enalapril, on experimental ACAD in a rat cardiac transplant model (Fisher to Lewis). METHODS: After grafting, recipients were treated with 10 mg/kg/day per os Losartan or 40 mg/kg/day per os Enalapril. Two groups of animals received additional pre-treatment with Losartan or Enalapril 7 days before transplantation. All study groups, including the control group, received immunosuppression with cyclosporine (3 mg/kg/day sub-cutaneously). We assessed the extent of ACAD of large and small arteries 80 days after grafting using digitizing morphometry. RESULTS: We observed significant reduction of neointimal proliferation in small arteries in Losartan pre- and post-treated and in Enalapril pre-treated recipients compared with the cyclosporine-treated group (p < 0.05). In epicardial arteries, Enalapril pre- and post-treatment as well as Losartan post-treatment significantly reduced neointimal formation compared with the control group. Reduction of neointima by Enalapril post-treatment in small arteries and Losartan pre-treatment in large arteries trended toward but failed statistical significance. CONCLUSIONS: Our results suggest the important role of the renin-angiotensin system in neointimal proliferation, which can be reduced equally with ACE inhibitors or the angiotensin-II blocker. Therefore AT(1) blockade with Losartan is a useful therapeutic strategy for inhibition of ACAD after cardiac transplantation.

Summary of Recent Developments in Primordial Nucleosynthesis.

This paper summarizes the recent observational and theoretical results on Big Bang Nucleosynthesis. In particular, it is shown that the new Pop II (6)Li results strongly support the argument that the Spite Plateau lithium is a good estimate of the primordial value. The (6)Li is consistent with the Be and Be found in Pop II stars, assuming those elements are cosmic ray produced. The HST (2)D value tightens the (2)D arguments and the observation of the (3)He in planetary nebula strengthens the (3)He +(2)D argument as a lower bound on Ωb. The new low metalicity (4)He determinations slightly raise the best primordial (4)He number and thus make a better fit and avoid a potential problem. The quark-hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Ωb are possible vis-à-vis the homogeneous model; hence, the robustness of Ωb∼ 0.05 is now apparent. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Ωb∼ 1 seems to be definitely excluded, so, if Ω= 1, as some recent observations may hint, then non-baryonic dark matter is required.

Spectral analysis of electroencephalogram during sleep-related apneas in pre-term and term born infants in the first weeks of life.

OBJECTIVES: A correlation between sudden infant death syndrome (SIDS) and apnea has been discussed in a variety of studies. We analyzed polysomnographic data in 51 infants and investigated correlations between the manifestation of apneas and changes in EEG pattern. METHODS: Measurements were performed by means of the commercial polysomnographic device 'ALICE III'. Spectral analysis of certain parts of the registered EEG was performed. RESULTS: During apnea a reduction of the EEG amplitude was seen. The extent of the decrease differed slightly between the frequency bands. CONCLUSIONS: According to the widespread agreement that a lower voltage of electrical brain activity is a fundamental sign of waking up, we hypothesize that the observed change might be an immature type of arousal reaction.

Flavonoid transport by mammalian endothelial cells.

Despite the ever-growing body of literature reporting the effects of flavonoids on animals at both the cellular and systemic levels, one of the most basic questions-"Are the effects of flavonoids on animal cells initiated through their interaction with extracellular targets or intracellular targets?"-has yet to be addressed. Because many effects of flavonoids on cells can be detected within minutes of flavonoid application and because flavonoids diffuse across lipid membranes slowly or not at all, intracellular mechanisms would necessitate a flavonoid transport system for rapid flavonoid uptake. The specific aims of this investigation were (1) to determine if endothelial cells contain a mechanism that mediates rapid flavonoid uptake and (2) to provide evidence for or against the hypothesis that rapid flavonoid effects on endothelial cell synthesis of prostacyclin and endothelin are initiated through the interaction of flavonoids with intracellular targets. Data show that bovine and human aortic endothelial cells possess a transport system that mediates rapid uptake of the flavonoid morin and suggest that the flavonoid uptake system utilizes a variety of oxygenated phenolic compounds as substrates. Further investigation into flavonoid transport should expedite future investigation into the mechanisms of flavonoid actions, because it may allow research to focus on the cellular locations where flavonoids are concentrated. Although endothelial cells contain a mechanism for the rapid uptake of morin, data reported herein suggest that morin initiates its rapid effects on endothelial cell synthesis of prostacyclin and endothelin through an interaction with extracellular targets.

The retrolabyrinthine approach and vascular loop.

Several researchers have made progress toward determining the cause of hemifacial spasm, tinnitus, and episodic vertigo. During the past 5 years, we have encountered a vascular loop in six of 36 patients who were undergoing retrolabyrinthine vestibular neurectomy for recurrent disequilibrium and vertigo. In five of these six patients, disequilibrium improved after neurectomy. This report describes the clinical symptomatology and the results of preoperative cochleovestibular testing for those patients found intraoperatively to have a vascular loop and suspected neurovascular compression syndrome. Audiograms, although varied, characteristically did not demonstrate the low-frequency sensorineural hearing loss characteristic of Meniere's disease. No preoperative marker, with the single exception of computed tomography pneumocisternography, dependably predicted the presence of a vascular loop.

Computed tomography: how accurate a predictor for cochlear implantation?

Cochlear implantation is an accepted medical treatment for profound bilateral postlinguistically acquired hearing loss. Because cochlear implants are still in the process of development, a detailed evaluation of the results of implantation is essential. However, the capability of predetermining the auditory benefit of a cochlear implant is limited and depends upon a number of factors. This report focuses upon the ability of computed tomography (CT) to predict surgical success and audiological results of multichannel cochlear implantation. It also addresses how the disease state might affect the functional benefit of the implant. After undergoing routine clinical and audiological evaluations, 28 cochlear implant candidates underwent CT scans in order to evaluate cochlear patency prior to surgery. Subsequently, 24 patients were implanted with either a single-or 22-channel device. Surgical findings were noted and postoperative audiological assessments of sound detection and speech discrimination were made. The CT risk factors that diminish the likelihood of a successful cochlear implant result are discussed based upon a retrospective comparison of preoperative CT results, surgical findings, and postsurgical audiological evaluations of the 14 patients who received a 22-channel implant. Analysis of the predictive capability of CT will allow clinicians to use that procedure more effectively in the presurgical assessment of cochlear implant candidates.

Aminoglycoside ototoxicity: a human temporal bone study.

OBJECTIVE: Hearing loss after aminoglycoside administration has been thought to result primarily from hair cell injury. The purpose of the study was to determine the potential for direct injury of spiral ganglion cells and hair cells in cases of documented human aminoglycoside ototoxicity. STUDY DESIGN: Retrospective case review. METHODS: The clinical course of two individuals with aminoglycoside ototoxicity are documented, including the details of administration of tobramycin and other ototoxic medication and serial audiograms. The temporal bones were processed, and the cochlear elements quantified. RESULTS: Histopathological study of the temporal bones from the individuals in the study demonstrated reduction of both ganglion cell and hair cell populations. Spiral ganglion cell loss was not necessarily subadjacent to areas of hair cell loss in cases of aminoglycoside ototoxicity. Instead, spiral ganglion cell reduction may be present in segments of the cochlea with normal-appearing hair cells. CONCLUSIONS: The study suggests that aminoglycoside antibiotics can injure spiral ganglion cells directly, as well as hair cells. Thus, the characteristic hearing loss of ototoxicity can result from degeneration of either cochlear element.