The novel cardiac myosin activator omecamtiv mecarbil increases the calcium sensitivity of force production in isolated cardiomyocytes and skeletal muscle fibres of the rat.

BACKGROUND AND PURPOSE: Omecamtiv mecarbil (OM) is a novel cardiac myosin activator drug for inotropic support in systolic heart failure. Here we have assessed the concentration-dependent mechanical effects of OM in permeabilized cardiomyocyte-sized preparations and single skeletal muscle fibres of Wistar-Kyoto rats under isometric conditions. EXPERIMENTAL APPROACHES: Ca2+ -dependent active force production (Factive ), its Ca2+ sensitivity (pCa50 ), the kinetic characteristics of Ca2+ -regulated activation and relaxation, and Ca2+ -independent passive force (Fpassive ) were monitored in Triton X-100-skinned preparations with and without OM (3nM-10 µM). KEY RESULTS: In permeabilized cardiomyocytes, OM increased the Ca2+ sensitivity of force production (ΔpCa50 : 0.11 or 0.34 at 0.1 or 1 µM respectively). The concentration-response relationship of the Ca2+ sensitization was bell-shaped, with maximal effects at 0.3-1 µM OM (EC50 : 0.08 ± 0.01 µM). The kinetics of force development and relaxation slowed progressively with increasing OM concentration. Moreover, OM increased Fpassive in the cardiomyocytes with an apparent EC50 value of 0.26 ± 0.11 µM. OM-evoked effects in the diaphragm muscle fibres with intrinsically slow kinetics were largely similar to those in cardiomyocytes, while they were less apparent in muscle fibres with fast kinetics. CONCLUSIONS AND IMPLICATIONS: OM acted as a Ca2+ -sensitizing agent with a downstream mechanism of action in both cardiomyocytes and diaphragm muscle fibres. The mechanism of action of OM is connected to slowed activation-relaxation kinetics and at higher OM concentrations increased Fpassive production.

Myeloperoxidase evokes substantial vasomotor responses in isolated skeletal muscle arterioles of the rat.

AIMS: Myeloperoxidase (MPO) catalyses the formation of a wide variety of oxidants, including hypochlorous acid (HOCl), and contributes to cardiovascular disease progression. We hypothesized that during its action MPO evokes substantial vasomotor responses. METHODS: Following exposure to MPO (1.92 mU mL(-1)) in the presence of increasing concentrations of hydrogen peroxide (H2O2), changes in arteriolar diameter of isolated gracilis skeletal muscle arterioles (SMAs) and coronary arterioles (CAs) and in the isometric force in basilar arteries (BAs) of the rat were monitored. RESULTS: Myeloperoxidase increased vascular tone to different degrees in CAs, SMAs and BAs. The mechanism of increased vasoconstriction was studied in detail in SMAs. MPO-evoked vasoconstrictions were prevented by the MPO inhibitor 4-aminobenzhydrazide (50 µM), by endothelium removal in the SMAs. Surprisingly, the HOCl scavenger L-methionine (100 µM), the thromboxane A2 (TXA2) antagonist SQ-29548 (1 µM) or the non-specific cyclooxygenase (COX) antagonist indomethacin (1 µM) converted the MPO-evoked vasoconstrictions to pronounced vasodilations in SMAs, not seen in the presence of H2O2. In contrast to noradrenaline-induced vasoconstrictions, the MPO-evoked vasoconstrictions were not accompanied by significant increases in arteriolar [Ca(2+)] levels in SMAs. CONCLUSION: These data showed that H2O2 -derived HOCl to be a potent vasoconstrictor upon MPO application. HOCl activated the COX pathway, causing the synthesis and release of a TXA2-like substance to increase the Ca(2+) sensitivity of the contractile apparatus in vascular smooth muscle cells and thereby to augment H2 O2 -evoked vasoconstrictions. Nevertheless, inhibition of the HOCl-COX-TXA2 pathway unmasked the effects of additional MPO-derived radicals with a marked vasodilatory potential in SMAs.

New formulation of in situ gelling Metolose-based liquid suppository.

CONTEXT: An in situ gelling liquid suppository is liquid at room temperature but forms a gel at body temperature. In our work, Metolose® SM-4000 (methylcellulose) is studied that basically shows thermal gelation at 68°C (2%, w/w). OBJECTIVE: The objective was to study the potency of different factors (concentration, pH, additives) to change the value of thermal gelation temperature (T (t)) for Metolose® to form an in situ gelling liquid suppository. MATERIALS AND METHODS: We studied the effect of Metolose® concentration, pH, and salts (sodium chloride, potassium chloride, sodium hydrogen carbonate, and sodium monohydrogen phosphate) on T (t) by viscosimetry. To choose the appropriate compound, in vitro drug release was examined. Rectal safety test was performed on rats in vivo after 12-hour application. RESULTS: Increasing the Metolose® concentrations (0.5-4%, w/w), T (t) can be decreased, but it also altered the consistency of gel. pH does not affect the T (t). The water-soluble salts allowed reducing the gelation temperature to 37°C. Sodium monohydrogen phosphate in 4.5% concentration was found to be the most appropriate. The impact of examined factors on in vitro drug release of piroxicam from the in situ-formed gel was characterized according to Fickian diffusion. Metolose® and the chosen salt did not cause any morphological damage on the rectal tissues. DISCUSSION: According to our study, Metolose® has the physical and chemical potential to be used as base for liquid suppositories.

Impaired p53 binding to importin: a novel mechanism of cytoplasmic sequestration identified in oxaliplatin-resistant cells.

Previous studies have described one nuclear localization signal (NLSI) in p53 and speculated on two additional sites termed NLSII and NLSIII. Drug-resistant KB cells selected with cisplatin or oxaliplatin were found to have increased p53 levels and in oxaliplatin-selected cells, a larger p53 predominantly in the cytoplasm. In oxaliplatin-selected cells a single nucleotide deletion in the sequence-encoding amino acid 382, part of NLSIII, resulted in a frame shift and a 420 amino acid protein (p53(420)). We investigated explanations for the cytoplasmic sequestration of p53(420) while assessing the role, if any, of NLSII and NLSIII in p53 nuclear import. We found that neither NLSII nor NLSIII are essential for p53 nuclear localization. Furthermore, we confirmed p53(420) is able to tetramerize, transactivate a p21 promoter, bind dynein and that the reduced nuclear accumulation is not a consequence of increased p53 nuclear export. However, the association of p53(420) with importin-beta, essential for nuclear import, was significantly impaired. We conclude that despite sequence similarity to consensus NLSs neither NLSII nor NLSIII have roles in p53 nuclear transport. We also identified impaired association with importin as a novel mechanism of p53 cytoplasmic sequestration that impairs nuclear transport rendering cells functionally deficient in p53.

Formulation of thermoresponsive and bioadhesive gel for treatment of oesophageal pain and inflammation.

The aim of this study was the formulation and examination of a novel thermoresponsive and bioadhesive, in situ gelling drug delivery system, which can be used in the treatment of oesophageal pain and inflammation. A bioadhesive cellulose derivative (Metolose) 60SH) was used as a thermoresponsive material, because Metolose has thermal gelation properties at certain temperature. The thermal gelation temperature (T(2)) of Metolose 60SH 2 w/w% solution is above body temperature (65-66 degrees C), but by using different methods (Metolose 60SH concentration, auxiliary materials), it can be shifted near to body temperature. The pH alteration between pH=2-10 and the application of different alcohols did not influence the gelation temperature, but using water-soluble salts and changing the concentration of Metolose 60SH solution between 2 and 3 w/w% the thermal gelation point could be decreased. Different NSAIDs were used as model drugs and which had not influence on thermal gelation temperature, but difference in in vitro liberation and penetration can be observed. In vitro adhesion test pointed out that the condition of investigated membrane can change the adhesion. Morphological test of oesophageal tissue showed that investigated materials had no irritative or tissue-damaging effect on the oesophageal mucosa even after 12h.

Child labor: a forgotten focus for child welfare.

Child labor is driven by child and family impoverishment, market forces, and political apathy concerning the rights of the child. Although a fundamental concern of the early 20th century child welfare system, today child labor is often seen as outside the scope of child welfare and child protective services. Making child labor a focus of child advocacy activity once again could do much to better the lives of children.

The multinational transfer of competency-based foster parent assessment, selection, and training: a nine-country case study.

The UN Convention on the Rights of the Child mandates (Articles 19 and 20) that alternative care be available to protect children from maltreatment by parents and caregivers. Increasingly, countries around the world have recognized the benefits to child well-being of family-based care as an alternative to institutional care. The special if not extraordinary needs of children separated from parents because of abuse, neglect, and maltreatment and placed with foster families requires a commensurate effort to develop foster families who have special if not extraordinary skills. Methods that are effective and replicable across countries offer significant advantages, reducing investments in policies and practices that otherwise would have to be developed independently, country by country. This case study describes the factors that contributed to the transfer of knowledge in the assessment, selection, and training of foster parents and the impact to date.

[Reflections about the relationship of science and art]. / Gondolatok a tudomány és a múvészet viszonyáról.

Science is dealing with the nature, the human beings and the society, and aims to explore the laws of their existence. It uses universal scientific methods, by taking all known laws of nature into consideration. It is free of subjectivity and is guided by a high degree of consciousness. In the author's view, the goal of science is to create a balance between man and nature by exploring the rules of the universe. Art, on the other hand, carries a message about the man and the world, which originates in both emotion and intuition. It intends to impress our feelings and wishes to entertain, create pleasure or make us accept its message. One might wonder about the nature of relationship between art and science. Do we scientists waste our valuable time when dealing with art? Furthermore, is it of any use for artists to deal with science? Ever since the ancient times, scientists have been highly appreciated. Artists, however, used to belong to lower social classes up until the 18th century. Still, the commercial and political life of the Middle Ages were greatly influenced by the guildes, where artists as craftsmen belonged to. Art and science have always been interconnected, although their contents and messages kept changing during the centuries. In the 5th century, sciences were listed among the "septem artes liberales", the "seven free arts". When comparing the creative process of art and science, we might find similarities and differences, some of which will be discussed in the paper. Both research and clinical profession demands devoted work. One of the most valuable form of stress reduction and relaxation is the enjoyment or practice of art. Engagement in art as a form of hobby widens our horizon which in turn stimulates professional work. We might as well agree with the wise saying: Without hobby, one can neither relax nor concentrate.

Effect of vasoactive intestinal polypeptide (VIP) on growth hormone (GH) and prolactin (PRL) release and cell morphology in human pituitary adenoma cell cultures.

Six GH adenomas and three prolactinomas were investigated by light- and electron-microscopic morphological and immunocytochemical methods and the effect of vasoactive intestinal polypeptide (VIP) on growth hormone (GH) and prolactin (PRL) secretion was tested in vitro. The tumour cells of the acromegalic patients revealed both GH and PRL immunoreactivity while prolactinomas showed only PRL activity. All the adenomas stained immunocytochemically also for VIP. By electron microscopy, the tumours included two densely and two sparsely granulated GH, two mixed GH/PRL, and three sparsely granulated PRL adenomas. The dissociated cells were explanted, and cultured in vitro. The cultures in micro test plates were treated with VIP at different concentrations between 10(-5)-10(-12) M. GH and PRL contents in the culture media were measured by radioimmunoassay. GH release was significantly stimulated by VIP in a dose-dependent manner over the whole concentration range, while VIP was effective on the PRL release only at 10(-6)-10(-7) M concentration. The cells of a mixed adenoma were grown in Petri dishes and used for ultrastructural and immunocytochemical studies. The cytoplasmic structure of the cells treated with VIP corresponded to that of active hormone-secreting cells with large ergastoplasmic fields and Golgi zones containing secretory granules. Massive exocytotic events were encountered mainly in the GH-type cells. GH and PRL double immunocytochemistry showed the predominance of GH cells, many of them containing low amounts of PRL as well. Cells predominantly containing PRL were spread among them, they also might contain GH as well. Some of the cells contained only a single immunoreactive hormone. The intensity of gold labelling of the secretory granules appeared higher in the VIP-treated cells than in the untreated control ones which showed a cytoplasmic structure characteristic of glandular cells with low secretory activity. As all the adenoma cells both contained and reacted to VIP, our results are in agreement with an autocrine or paracrine effect of this peptide. The fine structure of the cells in the cultures treated with VIP supply an additional argument to the assumption that VIP may serve as a growth factor for these cell types.

[Diagnostic possibilities in gastric leiomyoma in relation to two of our cases]. / A gyomor leiomyomájának diagnosztikai lehetöségeiröl--két esetünk kapcsán.

Two cases of rare, benignant gastric tumors are reported. The suggest that while in the diagnosis of tumors with a mucous membrane involvement endoscopy has doubtless a leading role, tumors not infiltrating the mucous membrane are usually better recognizable by radiological (ultrasonography, computer tomography and double contrast x-ray) methods. An appropriate diagnosis followed by surgical removal of the tumor might result in a complete healing of the patient.

[Diagnosis of Meckel diverticulum, containing ectopic gastric mucosa", by studying small bowel passage]. / Ectopiás gyomornyálkahártyát tartalmazó Meckel-diverticulum felismerése vékonybél-passage vizsgálattal.

Radiological diagnosis of Meckel diverticulum is a difficult task. Here we report a patient with hereditary sphaerocytosis who complained of a chronic periumbilical pain and in whom antegrade barium enema suggested Meckel diverticulum. The diagnosis had been proven both surgically and histologically. This observation indicates that so called traditional x-ray still has its role even in the era of modern (and expensive) radiology.

Transformation of a human mixed GH-PRL adenoma cell population in response to long-term bromocriptine treatment.

A child was operated 3 times because of a recurrent growth hormone- and prolactin-producing pituitary adenoma. Between the operations she was treated for five years with bromocriptine. The characteristics of the tumour cell population collected after the last operation was now examined by electron microscopy, immunocytochemistry, and in tissue culture and compared to those of the primary tumour cells reported earlier. A prominent change was the reversal of the proportion of the densely and sparsely granulated cells in favour of the GH-type, densely granulated cells. These cells, some of them coexpressing PRL, did not essentially change their characteristics either in vivo or in culture. On the other hand, pleomorphous cells with smaller cytoplasmic area and prominent lysosomal structures represented the sparsely granulated population containing PRL or both PRL and GH. The morphological alteration of the PRL-type cells was also reflected in vitro. Hence, while GH-type cells prevail, at least a sub-population of PRL-type cells survives long-term bromocriptine administration. A shift in the incidence of the two cell types in favour of the GH-type cells explains the change in the endocrine status of the patient.

Treatment of cystic craniopharyngiomas with yttrium-90 colloid solution.

The authors analyzed long-term follow-up data to assess the value of intracavitary irradiation with stereotactically implanted beta-emitting radioisotope (90)Y-silicate colloid for the treatment of craniopharyngiomas. Fifty-seven craniopharyngiomas in 42 patients were selected for retrospective analysis. The yttrium-90 was implanted intracavitally, using computerized tomography-guided and three-dimensional stereotactic treatment planning. The cumulative dose aimed at the inner surface of the cyst wall was 300 Gy. An average of 75% shrinkage of the initial cyst volume was observed. In 18 cases the reduction was more than 91%, and the cyst disappeared totally in 11 cases. A 50% decrease in cyst volume was usually apparent between the 2nd and 4th months. A 70% decrease in cyst volume was seen by the 5th and 6th months and an 80% reduction by the 7th and 8th months. Cysts that were unchanged remained so throughout the observation period. The time course of volume reduction could be expressed mathematically by the formula of 0.73 X e(-0.62 X T) + 0.27, where "e" is the basic number of natural logarithm and "T" is the time expressed in months. Mean survival duration after intracavitary irradiation was 9.4 years. The shrinkage of the cyst was a consequence of fibrosis of the wall, as seen on histopathological examination. The neuroophthalmological prognosis was favorable only when the optic disc was normal or nearly normal at the time of the treatment. In the presence of preexisting optic atrophy, visual deterioration proved to be irreversible. The long-term results support the view that intracavitary (90)Y-irradiation is a noninvasive and very effective method of treatment for craniopharyngioma cysts. Because of the 1.1 mm half-life decay of beta irradiation, it cannot influence the solid part of the tumor; therefore, the best result can be expected in solitary cysts.