The role of central autonomic nervous system dysfunction in Takotsubo syndrome: a systematic review

Clinical Autonomic Research - Takotsubo syndrome (TTS), also known as stress cardiomyopathy or “broken heart” syndrome, is a mysterious condition that often mimics an acute myocardial...     

Diagnosis of vascular prosthesis infection with FDG-PET/CT

Fluorodeoxyglucose positron emission tomography (FDG-PET) is on the verge of becoming an established imaging tool in the fields of clinical oncology, cardiology, and neurology. Because of the high glucose uptake of inflammatory cells, FDG scanning is an appropriate tool for use in tracing suspected inflammation or to evaluate infection. PET, although highly sensitive, often lacks the ability to define the precise anatomic location of abnormal FDG accumulation. The new PET/computed tomography (CT) technology provides precise registration of metabolic and structural imaging data in a single session. We report positive FDG-PET/CT findings in an infected vascular prosthesis 6 months after grafting. Our experience and a few available case reports support the hypothesis that FDG-PET/CT may have a promising role in future noninvasive diagnosis of infected vascular grafts.     

Role of CD4+ and CD8+ T lymphocytes in the protection of mice against Encephalitozoon intestinalis infection

Severe combined immunodeficient (SCID) mice reconstituted with spleen cells from naive adult BALB/c mice were completely resistant to peroral infection with Encephalitozoon intestinalis (Calli, Kotler and Orenstein, 1993) Canning, Field, Hing and Marriott, 1994, whereas control, non-reconstituted SCID mice succumbed to the infection. The role of T-lymphocyte subpopulations in the protection against peroral E. intestinalis infection was studied in adoptive transfer experiments using SCID mice. SCID mice reconstituted with both CD4+ and CD8+ T-lymphocyte-depleted splenocytes succumbed to the peroral route of infection. In contrast, SCID mice reconstituted with either CD4+-depleted or CD8+ T-lymphocyte-depleted splenocytes completely resolved the infection. This indicates that CD4+ and CD8+ T-lymphocyte subpopulations play a substantive role in protection against peroral infection with the microsporidian, E. intestinalis.     

Comparative biotransformation and disposition studies of nabumetone in humans and minipigs using high-performance liquid chromatography with ultraviolet,fluorescence and mass spectrometric detection

The disposition of the non-steroidal anti-inflammatory drug (NSAID) nabumetone after a single oral dose administration of nabumetone tablets to humans and minipigs was investigated. Nabumetone is a prodrug, which is metabolized in the organism to the principal pharmacodynamically active metabolite -- 6-methoxy-2-naphthylacetic acid (6-MNA), and some other minor metabolites (carbonyl group reduction products, O-desmethylation products and their conjugates with glucuronic and sulphuric acids). Standards of the above-mentioned metabolites were prepared using simple synthetic procedures and their structures were confirmed by NMR and mass spectrometry. A simple HPLC method for the simultaneous determination of nabumetone, 6-MNA and the other metabolites was developed, validated and used for xenobiochemical and pharmacokinetic studies in humans and minipigs and for distribution studies in minipigs. Naproxen was chosen as the internal standard (I.S.), both UV (for higher concentrations) and fluorescence detection (for very low concentrations) were used. The identity of the nabumetone metabolites in biological samples was confirmed using HPLC-MS experiments. Pharmacokinetics of nabumetone, 6-MNA and 6-HNA (6-hydroxy-2-naphthylacetic acid) in human and minipig plasma was evaluated and compared. The concentration levels of nabumetone metabolites in urine, bile and synovial fluid were also evaluated.     

Relationship between the structure and antimycobacterial activity of substituted salicylanilides

A series of 143 salicylanilides substituted in positions 4 and 5 and in positions 3' and 4' was synthesized. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium kansasii, and Mycobacterium avium. To describe the structure-antimycobacterial activity relationships (QSARs), an approach based on the combination of the Free-Wilson and Hansch methods was employed (the substituent constants were used in the case of the substituents on the phenyl ring; indicator parameters were used for the substituents on the acyl moiety). The relationships between the antimycobacterial activity and physico-chemical parameters of all substituents were also explored. The quadratic representation of lipophilicity parameters did not lead to significant correlations.     

High-performance liquid chromatographic determination of ursodeoxycholic acid after solid phase extraction of blood serum and detection-oriented derivatization

Ursodeoxycholic acid (3, 7β-dihydroxy-5β-cholanoic acid, UDCA) is a therapeutically applicable bile acid widely used for the dissolution of cholesterol-rich gallstones and in the treatment of chronic liver diseases associated with cholestasis. UDCA is more hydrophilic and less toxic than another therapeutically valuable bile acid, chenodeoxycholic acid (CDCA), the 7-epimer of UDCA. Procedures for sample preparation and HPLC determination of UDCA in blood serum were developed and validated. A higher homologue of UDCA containing an additional methylene group in the side chain was synthetized and used as an internal standard (IS). Serum samples with IS were diluted with a buffer (pH=7). The bile acids and IS were captured using solid phase extraction (C18 cartridges). The carboxylic group of the analytes was derivatized using 2-bromo-2′-acetonaphthone (a detection-oriented derivatization), and reaction mixtures were analyzed (HPLC with UV 245 nm detection; a 125–4 mm column containing Lichrospher 100 C18, 5 μm; mobile phase: acetonitrile–water, 6:4 (v/v)). Following validation, this method was used for pharmacokinetic studies of UDCA in humans.     

THE PERIPHERAL BLOOD LEUKOCYTE PHENOTYPE IN PATIENTS WITH BREAST CANCER: EFFECT OF DOXORUBICIN/PACLITAXEL COMBINATION CHEMOTHERAPY

Presence of functional immune system is critical for any attempt aimed at improving survival of breast cancer patients by strategies based on immune system manipulation. We evaluated by flow cytometry the phenotype of peripheral blood leukocyte of 43 breast cancer patients. In 11 patients, the phenotype was evaluated before and during the chemotherapy by combination of doxorubicin and paclitaxel (AT). Compared with controls breast cancer patients had significantly higher relative and absolute numbers of CD3^-HLADR⁺, CD3^-CD69⁺ and CD14⁺CD16^-, and significantly lower percentages of CD3^- and CD8^-CD28⁺ cells. After one cycle of AT, the absolute numbers of CD3⁺, CD3^-CD4^-, CD3⁺CD8⁺ and CD8^-CD28⁺ cells increased significantly. Present data show a presence of T-cell activation in breast cancer patients. Administration of AT may lead to an increase in functional T-cells in peripheral blood, indicating a potential for combining chemotherapy with immunotherapy in the treatment of breast cancer patients.     

Determination of cystathionine beta-synthase activity in human plasma by LC-MS/MS: potential use in diagnosis of CBS deficiency

Cystathionine β-synthase (CBS) deficiency is usually confirmed by assaying the enzyme activity in cultured skin fibroblasts. We investigated whether CBS is present in human plasma and whether determination of its activity in plasma could be used for diagnostic purposes. We developed an assay to measure CBS activity in 20 μL of plasma using a stable isotope substrate - 2,3,3-²H serine. The activity was determined by measurement of the product of enzyme reaction, 3,3-²H-cystathionine, using LC-MS/MS. The median enzyme activity in control plasma samples was 404 nmol/h/L (range 66–1,066; n = 57). In pyridoxine nonresponsive CBS deficient patients, the median plasma activity was 0 nmol/ho/L (range 0–9; n = 26), while in pyridoxine responsive patients the median activity was 16 nmol/hour/L (range 0–358; n = 28); this overlapped with the enzyme activity from control subject. The presence of CBS in human plasma was confirmed by an in silico search of the proteome database, and was further evidenced by the activation of CBS by S-adenosyl-L-methionine and pyridoxal 5′-phosphate, and by configuration of the detected reaction product, 3,3-²H-cystathionine, which was in agreement with the previously observed CBS reaction mechanism. We hypothesize that the CBS enzyme in plasma originates from liver cells, as the plasma CBS activities in patients with elevated liver aminotransferase activities were more than 30-fold increased. In this study, we have demonstrated that CBS is present in human plasma and that its catalytic activity is detectable by LC-MS/MS. CBS assay in human plasma brings new possibilities in the diagnosis of pyridoxine nonresponsive CBS deficiency.