Relativistic moduli space and critical velocity in kink collisions.

One important tool in the analysis of the collision of kinks and other topological solitons is the reduction of the original field theory to a finite-dimensional system of so-called collective coordinates. Here we study one recent proposal of a collective coordinate model (CCM), the perturbative relativistic moduli space (pRMS), where the amplitudes of the Derrick modes are promoted to collective coordinates. In particular, we analyze the possibility to calculate within the pRMS the critical velocity, i.e., the initial velocity of kinks at which single bounce scattering changes into a multibounce or annihilation collision. We find that for a growing number of Derrick modes the critical velocity of the CCM approaches the full field theory value. In particular, in the case of the ϕ^{4} model we reach a 99% accuracy. We also see this convergence for a wide range of models belonging to the family of the double sine-Gordon and Christ-Lee theories, especially in those cases where the kinks do not reveal a too well-pronounced half-kink inner structure.

Semi-Bogomol'nyi-Prasad-Sommerfield sphaleron and its dynamics.

We construct a simple field theory in which a sphaleron, i.e., a saddle-point particle-like solution, forms a semi-BPS state with a background defect that is an impurity. This means that there is no static force between the sphaleron and the impurity. Therefore, such a sphaleron-impurity system is very much like usual BPS multisolitons, however, still possessing an unstable direction allowing for its decay. We study dynamics of the sphaleron in such a system.

Collective Coordinate Model of Kink-Antikink Collisions in ϕ

The fractal velocity pattern in symmetric kink-antikink collisions in ϕ^{4} theory is shown to emerge from a dynamical model with two effective moduli: the kink-antikink separation and the internal shape mode amplitude. The shape mode usefully approximates Lorentz contractions of the kink and antikink, and the previously problematic null vector in the shape mode amplitude at zero separation is regularized.

Kink-antikink collisions in a weakly interacting ϕ

Kink-antikink scattering in nonintegrable field theories like ϕ^{4} theory is still rather poorly understood beyond brute-force numerical calculations, even after several decades of investigation. Recently, however, some progress has been made based on the introduction of certain self-dual background fields in these field theories which imply both the existence of static kink-antikink solutions of the Bogomol'nyi type and the possibility of an adiabatic scattering (moduli space approximation). Here we continue and generalize these investigations by introducing a one-parameter family of models interpolating between the Bogomol'nyi-Prasad-Sommerfield (BPS) model with the self-dual background field and the original ϕ^{4} theory. More concretely, we study kink-antikink scattering in a parameter range between the limit of no static force (BPS limit) and the regime where the static interaction between kink and antikink is small (non-BPS regime). This allows us to study the impact of the strength of the intersoliton static force on the soliton dynamics. In particular, we analyze how the transition of a bound mode through the mass threshold affects the soliton dynamics in a generic process, i.e., when a static intersoliton force shows up. We show that the thin, precisely localized spectral wall which forms in the limit of no static force broadens in a well-defined manner when a static force is included, giving rise to what we call a thick spectral wall. This phenomenon results from the appearance of a stationary saddle point solution where the acceleration of the solitons owing to the attractive force is compensated by the dynamics of the sufficiently excited mode. Thus, this barrier shows up before the mode crosses the mass threshold.

Spectral Walls in Soliton Collisions.

During defect-antidefect scattering, bound modes frequently disappear into the continuous spectrum before the defects themselves collide. This leads to a structural, nonperturbative change in the spectrum of small excitations. Sometimes the effect can be seen as a hard wall from which the defect can bounce off. We show the existence of these spectral walls and study their properties in the ϕ^{4} model with Bogomol'nyi-Prasad-Sommerfield preserving impurity, where the spectral wall phenomenon can be isolated because the static force between the antikink and the impurity vanishes. We conclude that such spectral walls should surround all solitons possessing internal modes.

Atrial natriuretic peptide and brain natriuretic peptide changes after epicardial percutaneous left atrial appendage suture ligation using LARIAT device.

Percutaneous left atrial appendage closure is an alternative treatment for stroke and systemic thromboembolism risk reduction in non-valvular atrial fibrillation (AF). However, the neurohormonal impact of epicardial exclusion of the left atrial appendage (LAA) with the LARIAT procedure is unknown. Evaluation of changes in atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels in AF patients underwent percutaneous LAA suture ligation. Sixty six patients underwent successfully percutaneous LAA suture ligation using LARIAT device. The level of ANP and BNP was measured before and 3 months after procedure. Mean ANP level before procedure was 249 ± 77 pg/mL (range from 95 pg/mL to 503 pg/mL) and mean BNP level was 481 ± 517 pg/mL (range from 34 pg/mL to 2508 pg/mL). Three months after procedure mean ANP level was 249 ± 79 pg/mL (range from 98 pg/mL to 492 pg/mL) and mean BNP level was 495 ± 526 pg/mL (range from 52 pg/mL to 2420 pg/mL). At 3 months follow up after percutaneous LAA suture ligation there were no significant differences in ANP and BNP levels.

Induced sputum supernatant bioactive lipid mediators can identify subtypes of asthma.

BACKGROUND: Induced sputum (IS) allows to measure mediators of asthmatic inflammation in bronchial secretions. The specific role of induced sputum supernatant (ISS) endogenous bioactive lipid mediators in subtypes of asthma is not well understood. OBJECTIVE: To investigate the interactions between airway inflammation and clinical phenotypes of asthma, we integrated induced sputum supernatant (ISS) eicosanoids and quantitative assessment of infiltrating cells into new subtypes with the means of latent class analysis (LCA). METHODS: One hundred and thirty-nine asthmatics with and without aspirin hypersensitivity underwent sputum induction. High-performance liquid chromatography or gas chromatography coupled with mass spectrometry was used to profile eicosanoids. Nineteen variables covering clinical characteristics, IS inflammatory cells and eicosanoids were considered in the LCA. RESULTS: Four phenotypic asthma classes were distinguished. Class 1 with mild-to-moderate asthma, chronic rhinosinusitis (CRS), high PGA2 in ISS and almost equal distribution of inflammation cell patterns. Class 3 subjects also had mild-to-moderate asthma but without upper airway symptoms. Induced sputum was often paucigranulocytic with low levels of lipid mediators. Classes 2 and 4 represented severe asthma with CRS and impaired lung function despite high doses of steroids. High blood and sputum eosinophilia was in line with high cysteinyl leukotrienes and PGD2 in ISS only in class 2. Class 4 subjects tended to have increased sputum neutrophilia and PGE2 in ISS. Aspirin hypersensitivity was most frequent among class 2 subjects. CONCLUSIONS & CLINICAL RELEVANCE: The LCA revealed four distinct asthma classes differing in eicosanoid pathways.

Transnasal endoscopic treatment of cerebrospinal fluid leaks: 10 years' experience.

The endoscopic repair of cerebrospinal fluid (CSF) leaks has become a routine procedure. This study describes the endoscopic closure of CSF leaks in a large series (36 patients) at the Jagiellonian University over 10 years (1999 to 2009). We describe the aetiology, defect location, graft material, presence of encephalocele, history of meningitis, intracranial pressure, recurrence, and follow-up. In our studies the aetiology of CSF leak was spontaneous in 4 cases, traumatic in 9, and iatrogenic in 23. The defect was most commonly located near the ethmoid and sphenoid bones. Our initial success rate after transnasal endoscopic treatment was 88.9% (32/36). However, the overall success rate of 97.2% (35/36) and the low morbidity in this series support the endoscopic approach as the standard of care for CSF leak closure. Follow-up ranged from 3 months to 5 years. Importantly, this high success rate can be achieved without the use of intrathecal fluorescein or a lumbar drain.

A case of respiratory epithelial adenomatoid hamartoma of the sinonasal tract.

Respiratory epithelial adenomatoid hamartoma is a rare, non-neoplastic tumour characterised by an abnormal mixture of tissues that are indigenous to the region. REAH are shiny, polypoid, exophytic masses with a rubbery to firm texture. They may arise and co-exist in the setting of inflammatory polyps. We present a case of a 49-year-old patient who was referred to the department with a clinical diagnosis of chronic nasal sinusitis. Results of post-op histopathological examination show a mild change of the respiratory epithelium requiring, among others, differentiation from inverted papilloma and adenoid carcinoma.

A giant cranial aneurysmal bone cyst associated with fibrous dysplasia.

An aneurysmal bone cyst (ABC) is a rare, benign fibro-osseous lesion, considered a vascular phenomenon secondary to fibrous dysplasia or a giant-cell tumour, and occurs mainly in long bones and vertebrae. In this case report a 16-year-old male presented with massive epistaxis. He was admitted with a 3-year history of chronic rhinitis, headaches, right ocular pain and recurrent epistaxis. CT scans showed a predominantly cystic, expansive mass obstructing both nasal cavities, extending to all paranasal sinuses and both orbits, with evidence of anterior cranial fossa skull base destruction. The patient underwent a craniofacial resection of the tumour performed with an external approach and an immediate reconstruction of the dural defect. Histology confirmed the lesion was an ABC associated with fibrous dysplasia. The patient's recovery was complete. A large facial aneurysmal bone cyst can damage the facial skeleton and skull base, and requires excision by a combined external approach.

Sphenoid sinus pyocele with intracranial extension managed under endoscopic guidance: a report of an extremely rare case.

OBJECTIVES: Sphenoid pyoceles with intracranial extension are extremely rare lesions that can mimic tumours and usually cause ophthalmological symptoms. Their infectious nature mandates urgent surgical decompression since pyoceles can cause intracranial and orbital complications. CASE REPORT: A 16-year-old male presented with intense headache and dizziness lasting three days. On admission, the patient gave a five-year history of chronic rhinitis, nasal congestion, and progressively worsening headaches. Ophthalmological examination was normal. CT and MR scans disclosed distension of the sphenoid sinus by a pyocele 55 mm in diameter, extending to the presellar region through the eroded cribriform plate. The patient underwent an endoscopic transnasal sphenoethmoidectomy. After surgery he reported improvement in all preoperative symptoms and was asymptomatic at 3-months follow-up. CONCLUSIONS: A huge sphenoid sinus pyocele with intracranial extension may cause no ophthalmological symptoms. It can be safely managed using endoscopic techniques.

Analysis of the antiepileptic drug keppra by capillary electrophoresis.

A simple and rapid method for determination of the new antiepileptic drug keppra (levetiracetam) by capillary electrophoresis in borate buffer containing sodium dodecyl sulfate is described. The serum was injected without any treatment. The method compared well to high performance liquid chromatography. The mean of keppra in the serum of 35 patients was 25 mg/l (range 7-77 mg/l).

Inhibition of endochondral ossification during fracture repair in experimental hypothyroid rats.

Using a rat fracture model, we investigated the effects of a decrease in serum levels of thyroid hormone on the fracture-repair process. Rats were divided into the following groups: (a) controls, (b) those treated with methimazole for the duration of the experiment, and (c) those treated with methimazole and L-thyroxine, receiving both for the same duration. Three weeks after the initiation of pharmacologic treatment, closed femoral fractures were produced. The formation of cartilage tissue in the fracture callus in all rats was not obviously different on day 7 after fracture. In the rats treated with methimazole, differentiation from proliferating to hypertrophic chondrocytes in the fracture callus was less advanced and vascular invasion was clearly inhibited on day 12. Gene expression of alkaline phosphatase and osteocalcin in the callus was significantly lower in these rats than in the controls on days 10, 12, and 14. The mechanical properties of the fracture callus were also significantly weaker in these animals than in the controls on day 21, resulting in impaired fracture repair. These results demonstrate that hypothyroidism inhibits endochondral ossification, resulting in an impaired fracture-repair process. L-thyroxine replacement in the rats treated with methimazole caused the impaired repair process to revert to normal. These results indicate that thyroid hormone is one of the critical systemic factors for fracture repair.

The effects of anagrelide on human megakaryocytopoiesis.

Anagrelide, an inhibitor of platelet aggregation, decreases the number of platelets in normal subjects and in patients with myeloproliferative disorders. We describe studies aimed at discovering the general mechanism(s) by which anagrelide acts. We examined three hypotheses: (1) anagrelide shortens platelet survival, (2) anagrelide inhibits the proliferation of megakaryocytic-committed progenitor cells (CFU-M), and (3) anagrelide inhibits maturation of megakaryocytes. We observed that anagrelide did not shorten platelet survival. Proliferation of CFU-M in vivo was not affected by anagrelide, although high concentrations of anagrelide inhibited CFU-M in vitro. In-vivo and in-vitro anagrelide altered the maturation of megakaryocytes, causing a decrease in their size and changing other morphometric features. We conclude that anagrelide decreases the number of platelets primarily by interfering with the maturation of megakaryocytes.

Serum lamotrigine analysis by capillary electrophoresis.

Lamotrigine, a new antiepileptic drug, is analyzed by capillary zone electrophoresis. Samples were deproteinized with acetonitrile containing an internal standard, acidified with dilute acetic acid and injected into the capillary. The drug migrated rapidly with the cationic compounds in about 3.5 min far from any interfering substances. The test was linear between 0.5-10 mg/l. The analysis time was about 5 min. The CE values correlated well with an HPLC method (r = 0.97; n = 35). The mean serum concentration of 121 patients on this drug was 3.7 mg/l. Incubating the serum with beta-glucuronidase for 1 h increased the peak height of lamotrigine by about 24%.

Acetazolamide in the treatment of seizures.

OBJECTIVE: To summarize the pharmacology, pharmacokinetics, efficacy, and safety of acetazolamide and to evaluate its therapeutic role in patients with epilepsy. DATA SOURCES: A computerized search of the MEDLINE (OVID) database (1966-1994) was used to identify publications regarding acetazolamide. The MEDLINE search was supplemented by information from textbooks. STUDY SELECTION: Included were English-language review articles, clinical trials, cohort studies, and case reports. Topics investigated included basic pharmacology, therapeutics, toxicology, adverse reactions, dosage, administration, and pharmacokinetics of acetazolamide. DATA SYNTHESIS: Acetazolamide, a carbonic anhydrase inhibitor, has been approved for the treatment of epilepsy since 1953. Acetazolamide is primarily used in combination therapy with other antiepileptic medications in both children and adults although it may be used as monotherapy. Drug concentration monitoring has not been found to be routinely beneficial. Adverse effects include kidney stones, metabolic acidosis, lethargy, appetite suppression, paresthesias, and rare blood dyscrasias. Partial tolerance may develop to the antiepileptic activity. CONCLUSIONS: Acetazolamide is a beneficial adjunctive agent in the pharmacotherapy of epilepsy and should be considered in refractory epilepsy. Although it may be useful in partial, myoclonic, absence, and primary generalized tonic-clonic seizures uncontrolled by other marketed agents, acetazolamide has been inadequately studied by current standards and its use has been limited.

Determination of gabapentin in serum by capillary electrophoresis.

A rapid capillary electrophoresis method for the quantification of gabapentin, a new anticonvulsant drug, in serum was developed. The assay involves derivatization of gabapentin with fluorescamine to provide a chromophore for UV-fluorescence detection. The migration time is about 11 min. The assay was linear between 0 and 20 mg/l. No other therapeutic drugs or amino acids interfered with the gabapentin peak. The relative standard deviation is 2.4% at a mean of 11 mg/l (n = 17). The mean serum level for 52 patients on this drug was 5.2 mg/l with a range of 0-12 mg/l.

[Treatment of big craniofacial injuries]. / Postepowanie lecznicze w przypadku rozleglych urazów twarzoczaszki.

The way of medical treatment in the case of vest craniofacial injuries is presented. Authors draw attention to plenty of complications connected with this type of injuries. Interdisciplinary proceeding was used with good therapeutic effect.

[Diagnostic and treatment difficulties in a case of nasal canal tumor]. / Trudnosci diagnostyczne i lecznicze w przypadku guza przewodu nosowego.

Problem of diagnostic and therapy in 14 year old boy with impairment of nasal air passage is presented. Authors used a CT investigation and arteriography of arteria carotis comm, to find out the largeness of disease alteration and to select the proper operative method.

Felbamate measured in serum by two methods: HPLC and capillary electrophoresis.

We have developed two methods for determining serum concentrations of felbamate, a new anticonvulsant drug. The first method is based on protein precipitation with acetonitrile, followed by HPLC. The between-run CV for this method is 5.7% (mean 55 mg/L), and the linearity extends from 5 to 175 mg/L. Results by this method compared well with those by an HPLC method based on chloroform extraction (r = 0.98, n = 21). In the second method, based on micellar electrokinetic capillary chromatography, the drug is measured by capillary electrophoresis with direct injection of serum. This method can be completed in 5 min compared with 12 min for the HPLC method, and there is no need for sample extraction. The between-run CV is 5.2% (mean 58 mg/L) and the linearity range is 5-160 mg/L. Results of this direct method correlated well (r = 0.98, n = 37) with those by the HPLC assay. The mean trough serum concentration of felbamate in 123 patients taking this drug was 44.9 mg/L (range 12-129 mg/L).