LncEGFL7OS regulates human angiogenesis by interacting with MAX at the EGFL7/miR-126 locus

In an effort to identify human endothelial cell (EC)-enriched lncRNAs,~500 lncRNAs were shown to be highly restricted in primary human ECs. Among them, lncEGFL7OS, located in the opposite strand of the EGFL7/miR-126 gene, is regulated by ETS factors through a bidirectional promoter in ECs. It is enriched in highly vascularized human tissues, and upregulated in the hearts of dilated cardiomyopathy patients. LncEGFL7OS silencing impairs angiogenesis as shown by EC/fibroblast co-culture, in vitro/in vivo and ex vivo human choroid sprouting angiogenesis assays, while lncEGFL7OS overexpression has the opposite function. Mechanistically, lncEGFL7OS is required for MAPK and AKT pathway activation by regulating EGFL7/miR-126 expression. MAX protein was identified as a lncEGFL7OS-interacting protein that functions to regulate histone acetylation in the EGFL7/miR-126 promoter/enhancer. CRISPR-mediated targeting of EGLF7/miR-126/lncEGFL7OS locus inhibits angiogenesis, inciting therapeutic potential of targeting this locus. Our study establishes lncEGFL7OS as a human/primate-specific EC-restricted lncRNA critical for human angiogenesis.

E-Cigarette Aerosol Exposure Induces Reactive Oxygen Species, DNA Damage, and Cell Death in Vascular Endothelial Cells

Cigarette smoking remains one of the leading causes of preventable death worldwide. Vascular cell death and dysfunction is a central or exacerbating component in the majority of cigarette smoking related pathologies. The recent development of the electronic nicotine delivery systems known as e-cigarettes provides an alternative to conventional cigarette smoking; however, the potential vascular health risks of e-cigarette use remain unclear. This study evaluates the effects of e-cigarette aerosol extract (EAE) and conventional cigarette smoke extract (CSE) on human umbilical vein endothelial cells (HUVECs). A laboratory apparatus was designed to produce extracts from e-cigarettes and conventional cigarettes according to established protocols for cigarette smoking. EAE or conventional CSE was applied to human vascular endothelial cells for 4-72 h, dependent on the assay. Treated cells were assayed for reactive oxygen species, DNA damage, cell viability, and markers of programmed cell death pathways. Additionally, the anti-oxidants α-tocopherol and n-acetyl-l-cysteine were used to attempt to rescue e-cigarette induced cell death. Our results indicate that e-cigarette aerosol is capable of inducing reactive oxygen species, causing DNA damage, and significantly reducing cell viability in a concentration dependent fashion. Immunofluorescent and flow cytometry analysis indicate that both the apoptosis and programmed necrosis pathways are triggered by e-cigarette aerosol treatment. Additionally, anti-oxidant treatment provides a partial rescue of the induced cell death, indicating that reactive oxygen species play a causal role in e-cigarette induced cytotoxicity.

Retinal pigment epithelial cell necroptosis in response to sodium iodate

Age-related macular degeneration (AMD) is a degenerative disease of the retina and the leading cause of blindness in the elderly in developed countries. The late stage of dry AMD, or geographic atrophy (GA), is characterized by extensive retinal pigment epithelium (RPE) degeneration. The underlying molecular mechanism for RPE cell death in GA remains unclear. Our previous study has established that RPE cells die predominantly from necroptosis in response to oxidative stress in vitro. Here, we extend our study and aim to characterize the nature of RPE cell death in response to sodium iodate (NaIO₃) in vitro and in a NaIO₃-induced retina degeneration mouse model. We found that NaIO₃ induces RPE necroptosis in vitro by using a combination of molecular hallmarks. By using TUNEL assays, active caspase-3 and HMGB1 immunostaining, we confirmed that photoreceptor cells die mainly from apoptosis and RPE cells die mainly from necroptosis in response to NaIO₃in vivo. RPE necroptosis in this model is also supported by use of the RIPK1 inhibitor, Necrostatin-1. Furthermore, using novel RIPK3-GFP transgenic mouse lines, we detected RIPK3 aggregation, a hallmark of necroptosis, in the RPE cells in vivo after NaIO₃ injection. Our findings suggest the necessity of re-evaluating RPE cell death mechanism in AMD models and have the potential to influence therapeutic development for dry AMD, especially GA.

Sun-induced fluorescence - a new probe of photosynthesis: First maps from the imaging spectrometer HyPlant

Variations in photosynthesis still cause substantial uncertainties in predicting photosynthetic CO2 uptake rates and monitoring plant stress. Changes in actual photosynthesis that are not related to greenness of vegetation are difficult to measure by reflectance based optical remote sensing techniques. Several activities are underway to evaluate the sun-induced fluorescence signal on the ground and on a coarse spatial scale using space-borne imaging spectrometers. Intermediate-scale observations using airborne-based imaging spectroscopy, which are critical to bridge the existing gap between small-scale field studies and global observations, are still insufficient. Here we present the first validated maps of sun-induced fluorescence in that critical, intermediate spatial resolution, employing the novel airborne imaging spectrometer HyPlant. HyPlant has an unprecedented spectral resolution, which allows for the first time quantifying sun-induced fluorescence fluxes in physical units according to the Fraunhofer Line Depth Principle that exploits solar and atmospheric absorption bands. Maps of sun-induced fluorescence show a large spatial variability between different vegetation types, which complement classical remote sensing approaches. Different crop types largely differ in emitting fluorescence that additionally changes within the seasonal cycle and thus may be related to the seasonal activation and deactivation of the photosynthetic machinery. We argue that sun-induced fluorescence emission is related to two processes: (i) the total absorbed radiation by photosynthetically active chlorophyll; and (ii) the functional status of actual photosynthesis and vegetation stress.

Current therapeutic developments in atrophic age-related macular degeneration

Age-related macular degeneration (AMD), a degenerative disorder of the central retina, is the leading cause of irreversible blindness in the elderly. The underlying mechanism of the advanced form of dry AMD, also named geographic atrophy (GA) or atrophic AMD, remains unclear. Consequently, no cure is available for dry AMD or GA. The only prevention option currently available is the Age-Related Eye Disease Study (AREDS) formulation, which has been demonstrated to slow down the progression of dry AMD. This review summarises recent advances in therapy for dry AMD and GA. Building on the new understanding of the disease and recent technological breakthroughs, numerous ongoing clinical trials have the goal of meeting the need to cure AMD. Therapeutic agents are being developed to target the key features of the disease, including inhibiting the complement pathway and other inflammatory pathways, reducing oxidative stress and protecting retinal pigment epithelial (RPE) cells, inhibiting lipofuscin and visual cycle, regenerating RPE cells from stem cells and restoring choroidal blood flow. Some of these therapeutic options, especially the stem cell-based therapy, hold great promise, which brings great hope for this devastating blinding disease.

RPE necroptosis in response to oxidative stress and in AMD

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly. The underlying mechanism of non-neovascular AMD (dry AMD), also named geographic atrophy (GA) remains unclear and the mechanism of retinal pigment epithelial (RPE) cell death in AMD is controversial. We review the history and recent progress in understanding the mechanism of RPE cell death induced by oxidative stress, in AMD mouse models, and in AMD patients. Due to the limitation of toolsets to distinguish between apoptosis and necroptosis (or necrosis), most previous research concludes that apoptosis is a major mechanism for RPE cell death in response to oxidative stress and in AMD. Recent studies suggest necroptosis as a major mechanism of RPE cell death in response to oxidative stress. Moreover, ultrastructural and histopathological studies support necrosis as major mechanism of RPE cells death in AMD. In this review, we discuss the mechanism of RPE cell death in response to oxidative stress, in AMD mouse models, and in human AMD patients. Based on the literature, we hypothesize that necroptosis is a major mechanism for RPE cell death in response to oxidative stress and in AMD.

4-Acetoxyphenol Prevents RPE Oxidative Stress-Induced Necrosis by Functioning as an NRF2 Stabilizer

PURPOSE

Oxidative stress has been suggested to be a major risk factor for the pathogenesis of AMD. Retinal pigment epithelial (RPE) cells are essential for maintaining the homeostasis of the retina, and RPE cell death and the resultant photoreceptor apoptosis have been observed in dry AMD, especially in geographic atrophy. The purpose of this article was to identify and repurpose the Food and Drug Administration-approved natural compound 4-Acetoxyphenol (4-AC), and to evaluate its effect and mechanism in protecting against oxidative stress-induced RPE necrosis.

METHODS

We exposed ARPE-19 cells to tert-Butyl hydroperoxide (tBHP) after pretreatment with 4-AC, and measured cell viability by MTT assay. Aggregation of RIPK3 and HMGB1 nuclear release were analyzed by transfected reporter genes. Reactive oxygen species (ROS) were measured using a commercially available ROS detection system. The importance of the NRF2/NQO1/HO-1 pathway in mediating 4-AC function was corroborated by siRNA studies, qRT-PCR, and immunostaining.

RESULTS

We have identified a natural antioxidant, 4-AC, which demonstrates strong abilities to protect RPE cells from oxidative stress-induced necrosis. Mechanistically, 4-AC blocked the increase of cellular ROS induced by oxidative stress, and upregulated NQO1 and HO-1 genes by stabilizing and inducing the nuclear translocation of NRF2 transcription factor. The NQO1, HO-1, and NRF2 were further shown to be required for 4-AC protection of RPE cells from death induced by tBHP. The tBHQ, an NRF2 stabilizer, consistently mimicked the protective effect of 4-AC against tBHP-induced RPE death.

CONCLUSIONS

The compound 4-AC protects ARPE-19 cells from oxidative stress-induced necrosis through upregulation of NQO1 and HO-1 genes by stabilization of NRF2.

Inhibition of multiple pathogenic pathways by histone deacetylase inhibitor SAHA in a corneal alkali-burn injury model

Neovascularization (NV) in the cornea is a major cause of vision impairment and corneal blindness. Hemangiogenesis and lymphangiogenesis induced by inflammation underlie the pathogenesis of corneal NV. The current mainstay treatment, corticosteroid, treats the inflammation associated with corneal NV, but is not satisfactory due to such side effects as cataract and the increase in intraocular pressure. It is imperative to develop a novel therapy that specifically targets the hemangiogenesis, lymphangiogenesis, and inflammation pathways underlying corneal NV. Histone deacetylase inhibitors (HDACi) have been in clinical trials for cancer and other diseases. In particular, HDACi suberoylanilide hydroxamic acid (SAHA, vorinostat, Zolinza) has been approved by the FDA for the treatment of cutaneous T-cell lymphoma. The functional mechanism of SAHA in cancer and especially in corneal NV remains unclear. Here, we show that topical application of SAHA inhibits neovascularization in an alkali-burn corneal injury model. Mechanistically, SAHA inhibits corneal NV by repressing hemangiogenesis, inflammation pathways, and previously overlooked lymphangiogenesis. Topical SAHA is well tolerated on the ocular surface. In addition, the potency of SAHA in corneal NV appears to be comparable to the current steroid therapy. SAHA may possess promising therapeutic potential in alkali-burn corneal injury and other inflammatory neovascularization disorders.

Direct interaction of Gas41 and Myc encoded by amplified genes in nervous system tumours

In order to understand better the role of the human Tip60 complex component Gas41, we analysed its expression levels in brain tumours and searched for possible interactors. Two-hybrid screening of a human foetal brain library allowed identification of some molecular interactors of Gas41. Among them we found n-Myc transcription factor. The interaction between Gas41 and n-Myc was validated by pull-down experiments. We showed that Gas41 is able to bind both n-Myc and c-Myc proteins, and that the levels of expression of Gas41 and Myc proteins were similar to each other in such brain tumors as neuroblastomas and glioblastomas. Finally, in order to identify which region of Gas41 is involved in the interaction with Myc proteins, we analysed the ability of Gas41 to substitute for its orthologue Yaf9 in yeast; we showed that the N-terminal portions of the two proteins, containing the YEATS domains, are interchangeable, while the C-terminal portions are species-specific. In fact we found that Gas41 C-terminal portion is required for Myc protein interaction in human.

Direct interaction of Gas41 and Myc encoded by amplified genes in nervous system tumours

In order to understand better the role of the human Tip60 complex component Gas41, we analysed its expression levels in brain tumours and searched for possible interactors. Two-hybrid screening of a human foetal brain library allowed identification of some molecular interactors of Gas41. Among them we found n-Myc transcription factor. The interaction between Gas41 and n-Myc was validated by pull-down experiments. We showed that Gas41 is able to bind both n-Myc and c-Myc proteins, and that the levels of expression of Gas41 and Myc proteins were similar to each other in such brain tumors as neuroblastomas and glioblastomas. Finally, in order to identify which region of Gas41 is involved in the interaction with Myc proteins, we analysed the ability of Gas41 to substitute for its orthologue Yaf9 in yeast; we showed that the N-terminal portions of the two proteins, containing the YEATS domains, are interchangeable, while the C-terminal portions are species-specific. In fact we found that Gas41 C-terminal portion is required for Myc protein interaction in human.

Identification of novel putative regulators of the major apoptotic nuclease DNA Fragmentation Factor

Yeast two- and three-hybrid systems were used to screen cDNA libraries from HeLa cells and human brain tissue to identify novel protein partners of DNA Fragmentation Factor, the major apoptotic nuclease. The two-hybrid system revealed the DFF45 inhibitory subunit of the nuclease as the only identified partner of the DFF40 catalytic subunit. Similar analysis revealed several protein candidates that potentially interact with the DFF45 subunit: FBXO28, FOSL1, PGK1, PCNT, FHL1 and GFAP. Recombinant GFAP protected DFF45 against cleavage with caspase-3 and prevented activation of the DFF nuclease in vitro. In addition, three-hybrid system results revealed a putative novel protein partner of the DFF40-DFF45 heterodimer. The candidate cDNA contained two open reading frames that mapped to an intron of the GBF1 gene. Products of the candidate cDNA derived from a cell-free transcription/translation system inhibited DNA cleavage by recombinant caspase-activated DFF. This putative partner of DFF may have functional importance in regulating the apoptotic response because its RNAi silencing facilitated cleavage of the DFF45 inhibitor subunit and affected chromatin fragmentation in HeLa cells undergoing apoptosis. This hypothetical protein, named DRIG based on an acronym specifying its genomic location, could be a novel factor involved in regulation of DFF40 apoptotic nuclease.

Identification of novel putative regulators of the major apoptotic nuclease DNA Fragmentation Factor

Yeast two- and three-hybrid systems were used to screen cDNA libraries from HeLa cells and human brain tissue to identify novel protein partners of DNA Fragmentation Factor, the major apoptotic nuclease. The two-hybrid system revealed the DFF45 inhibitory subunit of the nuclease as the only identified partner of the DFF40 catalytic subunit. Similar analysis revealed several protein candidates that potentially interact with the DFF45 subunit: FBXO28, FOSL1, PGK1, PCNT, FHL1 and GFAP. Recombinant GFAP protected DFF45 against cleavage with caspase-3 and prevented activation of the DFF nuclease in vitro. In addition, three-hybrid system results revealed a putative novel protein partner of the DFF40-DFF45 heterodimer. The candidate cDNA contained two open reading frames that mapped to an intron of the GBF1 gene. Products of the candidate cDNA derived from a cell-free transcription/translation system inhibited DNA cleavage by recombinant caspase-activated DFF. This putative partner of DFF may have functional importance in regulating the apoptotic response because its RNAi silencing facilitated cleavage of the DFF45 inhibitor subunit and affected chromatin fragmentation in HeLa cells undergoing apoptosis. This hypothetical protein, named DRIG based on an acronym specifying its genomic location, could be a novel factor involved in regulation of DFF40 apoptotic nuclease.

Models of stents - comparison and applications

The aim of this study was to analyze the possibilities of various types of stent modeling and to develop some new models. A brief survey of basic properties of stents and a list of basic designs of stents is presented. Two approaches to stent modeling were identified. Structural mechanics is the theoretical background of our analytical model of a spiral stent. The finite element method was also used. The measurement equipment for model evaluation was developed.

In vitro glycosidation potential towards olomoucine-type cyclin-dependent kinase inhibitors in rodent and primate microsomes

Interspecies differences in glycosidation potential in mammalian tissues represent a factor contributing to ambiguity when endobiotic and/or xenobiotic metabolic pathways are extrapolated from animals to man. Using the TLC/autoradiographic technique, we conducted an in vitro investigation involving mouse, rat, monkey, as well as human liver and kidney microsomes to evaluate their glycoconjugation potential towards (3)H-labeled, purine-derived selective inhibitors of cyclin-dependent kinases such as olomoucine, bohemine, roscovitine, 6-(2-hydroxybenzyl)amino-2-(1-hydroxymethyl-2-methylpropyl)amino-9-isopropylpurine (compound A-4), and 6-(3-hydroxybenzyl)amino-2-[(1(R/S)-hydroxymethyl)propyl]amino-9-isopropylpurine (compound A-5) as aglycones. Principally, this study confirmed the aliphatic hydroxyl group of olomoucine-type inhibitors as a relatively suitable target for glucuronide, glucoside, xyloside, galactoside, and/or N-acetylaminoglucoside conjugation. Of the tissues examined, only the mouse microsomes were able to perform glucosidation and galactosidation reactions with the aglycones. On the other hand, monkey microsomes were superior to the mouse microsomes in a variety of glucuronide conjugates produced with compounds A-4 and A-5.

In vitro biotransformation of 2,6,9-trisubstituted purine-derived cyclin-dependent kinase inhibitor bohemine by mouse liver microsomes

1. Biotransformation pathways of the cyclin-dependent kinase inhibitor 6-benzylamino-2-(3-hydroxypropylamino)-9-isopropylpurine (bohemine) by mouse liver microsomes in vitro were investigated. 2. Metabolite profiles of [8-(3)H]-labelled bohemine were established by TLC/(3)H-autoradiography and enzymatic and MS analyses were used to elucidate the chemical structures of the metabolites. The structures of the main primary metabolites were confirmed by synthesis of authentic compounds. 3. A schema of the primary NADPH-dependent pathways has been proposed involving N(2)- and N9-dealkylation, N(6)-debenzylation, aromatic hydroxylation, and C2 side chain oxidation of bohemine. Three of the primary metabolites detected, 6-(benzylamino)-2-(3-hydroxypropylamino)purine (M4), 6-amino-2-(3-hydroxypropylamino)-9-isopropylpurine (M5) and 6-(4-hydroxybenzylamino)-2-(3-hydroxypropylamino)-9-isopropylpurine (M6), all retaining their parent primary hydroxyl group, were subsequently shown to be converted, by a liver cytosolic NAD(+)-dependent system, into their corresponding carboxylic acids. M6 was subject to microsomal glycosidations requiring UDP-sugar donors. NADPH-dependent conversion of M6 into M5 by microsomes was also demonstrated. 4. Cytochrome P450 (CYP) enzymes-selective inhibitors were used to identify CYPs involved in bohemine biotransformation. The findings suggested that CYP2a and CYP3a substantially contributed to the NADPH-dependent bohemine transformation in vitro. 5. The findings will facilitate experiments designed to dissect enzymatic systems catalysing clearance of C2,C6,N9-trisubstituted purine compounds from mammalian tissues.

-CH2- lengthening of the internucleotide linkage in the ApA dimer can improve its conformational compatibility with its natural polynucleotide counterpart

The complete family of ApA phosphonate analogues with the internucleotide linkage elongated by insertion of a -CH2- group was prepared and the hybridisation and structural properties of its members in interaction with polyuridylic acid were investigated using an original 2D Raman approach. Except for the conformationally restricted A(CH)pA(2'3'endo-5') modification, all of the isopolar, non-isosteric analogues form triplex-like complexes with poly(rU) at room temperature, in which two polymer strands are bound by Watson-Crick and Hoogsteen bonds to a central pseudostrand consisting of a 'chain' of A-dimers. For all of these dimers, the overall conformation of the triplexes was found to be similar according to their extracted Raman spectra. A simple semi-empirical model was introduced to explain the observed dependency of the efficiency of triplex formation on the adenine concentration. Apparently, for most of the modifications studied, the creation of a stable complex at room temperature requires the formation of a central pseudostrand, consisting of several adenine dimers. Molecular dynamics calculations were finally performed to interpret the differences in 'cooperative' behaviour between the different dimers studied. The results indicate that the exceptional properties of the Ap(CH2)A(3'-5') dimer could be caused by the 3D conformational compatibility of this modified linkage with the second (Hoogsteen) poly(rU) strand.

In vivo metabolism of 2,6,9-trisubstituted purine-derived cyclin-dependent kinase inhibitor bohemine in mice: glucosidation as the principal metabolic route

Synthetic cyclin-dependent kinase inhibitors have recently been referred to as effective antiproliferative agents. This study was conducted to characterize clearance of a 3H-labeled, trisubstituted purine-type inhibitor, 8-[3H]bohemine [6-benzylamino-2-(3-hydroxypropylamino)-9-isopropylpurine], in mice. Radioactivity profiles were analyzed by liquid scintillation counting and by thin layer chromatography followed by autoradiography. Metabolite structures were elucidated by mass spectrometry, NMR, and enzymatic analyses. Bohemine was rapidly and completely metabolized in vivo and disappeared from circulation during the first 60 min following intravenous administration. The metabolites were partly eliminated by the hepatobiliary tract and partly by renal excretion. The terminal hydroxyl group located at the C2 side chain of bohemine made the compound susceptible to main metabolic attacks, i.e., distinct types of conjugation reactions with glycosyl donors as well as an oxidative reaction. Other pathways were of relatively minor significance. Bohemine O-beta-D-glucoside was the most abundant metabolite to be excreted. The enzymatic mechanism responsible for bohemine glucosidation in vitro required the presence of a UDP-glucoside donor. Additional glycosidation products were observed after inclusion of UDP-glucuronide, UDP-xylose, UDP-galactose, or UDP-N-acetylglucosamine into microsomal incubates. Glycosidations occurred faster in the kidney incubates than in hepatic ones. The second principal bohemine metabolite was a carboxylic acid, 6-benzylamino-2-(2-carboxyethylamino)-9-isopropylpurine. A cytosolic, 4-methylpyrazole-sensitive alcohol dehydrogenase class I was shown to mediate oxidation of the terminal hydroxyl group of bohemine into this acid, which was the only metabolite found in the blood in significant amounts. However, it displayed only weak cyclin-dependent kinase-1-inhibitory activity (IC(50) > 100 microM) when compared with that of bohemine (IC(50) approximately 1 microM).

Natural and azido fatty acids inhibit phosphate transport and activate fatty acid anion uniport mediated by the mitochondrial phosphate carrier

The electroneutral P(i) uptake via the phosphate carrier (PIC) in rat liver and heart mitochondria is inhibited by fatty acids (FAs), by 12-(4-azido-2-nitrophenylamino)dodecanoic acid (AzDA) and heptylbenzoic acid ( approximately 1 microm doses) and by lauric, palmitic, or 12-azidododecanoic acids ( approximately 0.1 mm doses). In turn, reconstituted E. coli-expressed yeast PIC mediated anionic FA uniport with a similar pattern leading to FA cycling and H(+) uniport. The kinetics of P(i)/P(i) exchange on recombinant PIC in the presence of AzDA better corresponded to a competitive inhibition mechanism. Methanephosphonate was identified as a new PIC substrate. Decanephosphonate, butanephosphonate, 4-nitrophenylphosphate, and other P(i) analogs were not translocated and did not inhibit P(i) transport. However, methylenediphosphonate and iminodi(methylenephosphonate) inhibited both electroneutral P(i) uptake and FA cycling via PIC. AzDA analog 16-(4-azido-2-nitrophenylamino)-[(3)H(4)]-hexadecanoic acid ((3)H-AzHA) bound upon photoactivation to several mitochondrial proteins, including the 30- and 34-kDa bands. The latter was ascribed to PIC due to its specific elution pattern on Blue Sepharose and Affi-Gel. (3)H-AzHA photolabeling of recombinant PIC was prevented by methanephosphonate and diphosphonates and after premodification with 4-azido-2-nitrophenylphosphate. Hence, the demonstrated PIC interaction with monovalent long-chain FA anions, but with divalent phosphonates of short chain only, indicates a pattern distinct from that valid for the mitochondrial uncoupling protein-1.

[Use of thermoelectric properties of materials with shape memory in medicine]

Article deals with some possibilities of the combination of the shape memory and another physical properties of nitinol (Ti-Ni alloy) for application in the medicine. The thermoelectric properties of originally developed miniature thermocouple probe with the shape memory are described in details. The shape memory effect of the thermocouple is based on the use of the combination of the metals nitinol and constantan.

[Tools and methods of developing educational programs in medical biophysics]

In this work various types of programs which can be used in a learning and teaching process are analysed. Also the procedure of creating software for CAL is studied and the procedure, that is the most suitable one for developing CAL is suggested here. Also recommended properties of software for teaching and learning medical biophysics are described. General characteristics and types of authoring tools are discussed in this work and a set of authoring tools is described in more details. Conclusions are documented and demonstrated by program Blood Circulation. For development of this program the authoring system Authorware 3.5 was selected. The program is organized as a hypertext with possibility to find words, with a list of the last visited pages, and with an on line help system. This program works with a text, graphics, interactive animated schemes and with interactive equations. In the program it is possible to test the level of knowledge by means of solving problems or multiply choice test.

Technical note: Parasitic thermovoltage in the multithermocouple probe, its explanation and elimination

The parasitic thermovoltage can influence the temperature measurement during hyperthermia using the miniature multithermocouple probes with a common wire. It was noticed that, when a thermocouple junction is placed in a sharp thermal gradient, a parasitic thermovoltage is added to the voltage of all remaining thermocouples situated in the direction to the tip of the probe. This article gives the theoretical explanation, experimental verification, and practical elimination of this phenomenon.

Induction of apoptosis and regression of spontaneous dog melanoma following in vivo application of synthetic cyclin-dependent kinase inhibitor olomoucine

This case report describes a dog with spontaneous melanoma of the orofacial region which was treated by a synthetic inhibitor of cyclin-dependent kinases, i.e. olomoucine (OC). The drug was applied i.v. in a single dose of 8 mg/kg/day for 7 days in succession. Repeated bioptic examinations of metastatic cervical lymph nodes showed rapid induction of apoptosis in tumor cells as early as on the third day of treatment. Standard clinical and laboratory examinations did not reveal side effects of the therapy. There were no detectable manifestations of myelosuppression, hepatotoxicity, nephrotoxicity or neurotoxicity. However, transient anemia developed following bleeding from a devitalized tumor mass. For this reason, the dog underwent surgery to minimize tumor load as well as to eliminate the source of bleeding. Two kilograms of primary tumor were extirpated in the course of surgery, including cervical node metastases. Unfortunately, the dog died soon after surgery due to respiratory depression. Histological examinations of the tumor tissue showed marked apoptosis of melanoma cells in both the primary tumor and metastases. The induction of programmed cell death of cancer cells by OC resulted in rapid eradication of at least 68% of the tumor cells. The remaining melanoma cells retained at least equally well in vitro sensitivity to OC as to drugs currently used in clinical practice.

Cytokinin-derived cyclin-dependent kinase inhibitors: synthesis and cdc2 inhibitory activity of olomoucine and related compounds

Cyclin-dependent kinases (cdk) have recently raised considerable interest in view of their essential role in the regulation of the cell division cycle. The structure-activity relationships of cdk inhibition showed that the 1, 3; and 7 positions of the purine ring must remain free, probably for a direct interaction, in which it behaves as a hydrogen bond acceptor. Olomoucine (6-(benzylamino)-2-[(2-hydroxyethyl)amino]-9-methylpurine, OC), roscovitine (6-(benzylamino)-2(R)-[[1-(hydroxymethyl)propyl]amino]-9-isopropylpur ine), and other N6,2,9-trisubstituted adenines were found to exert a strong inhibitory effect on the p34cdc2/cyclin B kinase. Removal or change of the side chain at position 2 or the hydrophobic group at position 9 dramatically decreased the inhibitory activity of olomoucine or roscovitine. Inhibition of cdk with OC and related compounds clearly arrests cell proliferation of many tumor cell lines at G1/S and G2/M transitions and also triggers apoptosis in the target tumor cells in vitro and in vivo. Thus, from a pharmacological point of view, OC may represent a model compound for a new class of antimitotic and antitumor drugs.

Photoaffinity labelling of the mitochondrial uncoupling protein by [3H]azido fatty acid affects the anion channel

Brown adipose tissue (BAT) mitochondria were incubated with the azido derivative of fatty acid (hexadecanoic) containing four tritium atoms, [3H]AzHA, and among all mitochondrial proteins only a few proteins were photolabelled after irradiation with UV. It suggests the existence of specific fatty acid binding sites on mitochondrial proteins. It was also possible to label with [3H]AzHA the isolated uncoupling protein (UcP) of BAT mitochondria with a low stoichiometry--lower than one AzHA per dimeric UcP. These results together with the observed competition (i.e. prevention of photolabelling) of various UcP anionic substrates with [3H]AzHA and its dodecanoic acid analogue, suggest the existence of the specific fatty acid binding site on UcP identical with the anion channel or anion translocating site.

Photoactivated azido fatty acid irreversibly inhibits anion and proton transport through the mitochondrial uncoupling protein

The protonophoretic function of uncoupling protein (UCP) is activated by fatty acids. According to the "docking site" hypothesis (Jezek, P., and Garlid, K. D., J. Biol. Chem. 265, 19303-19311, 1990), the fatty acid binding site is identical with the anion channel of UCP. Skulachev (Skulachev, V. P. (1991) FEBS Lett. 294, 158-162) extended this hypothesis by suggesting that fatty acid anions are transported by UCP and that H+ are delivered by back-diffusion of the protonated fatty acid through the lipid bilayer. In this model, UCP does not transport H+ at all but rather enables fatty acids to act as cycling protonophores. New evidence supports this mechanism (Garlid, K. D., Orosz, D. E., Modriansky, M., Vassanelli, S., and Jezek, P. (1996) J. Biol. Chem. 271, 2615-2620). To help elucidate these hypotheses, we synthesized a photoreactive analog of dodecanoic acid, 12-(4-azido-2-nitrophenylamino)dodecanoic acid (AzDA), and studied its effect on transport in mitochondria and proteoliposomes. AzDA behaved in every respect like a typical fatty acid. In micromolar doses, AzDA activated H+ translocation and inhibited Cl- and hexanesulfonate uniport through UCP. After UV light exposure, however, activation of H+ transport was inhibited, whereas inhibition of anion transport was preserved. These effects were irreversible. Photolabeling of mitochondria with [3H]AzDA resulted in a prominent 32 kDa band of UCP, and few other proteins were labeled. The results indicate that AzDA can be ligated to the protein at or near the docking site, causing irreversible inhibition of both H+ and anion transport. The finding that fatty acid-induced H+ transport disappears along with anion transport supports the fatty acid-protonophore mechanism of H+ transport by UCP.

Computer controlled multisensor thermocouple apparatus for invasive measurement of temperature

The computer controlled apparatus for invasive measurement of temperature profile of biological systems based on original miniature multithermocouple probe is described in this article. The main properties of measuring system were verified by using the original testing device.

In vitro release of hydrocortisone from topical preparations and automated procedure

The in vitro drug release profile of hydrocortisone (HC) from creams, ointments, and lotions has been determined using an automated procedure. A diffusion cell system and commercially available synthetic membranes were utilized for the studies. The use of a synthetic membrane obviates the problems associated with using skin membranes. Uniform creams and ointment samples for determining release rate profile were prepared by using the teflon mask. Automated sampling avoids operator artifacts. The automated technique developed for determining the in vitro release rate profile of the drug from creams, ointments, and lotions using a diffusion-cell system appears to be a reasonable and practical procedure for assuring batch-to-batch uniformity of topical drug products.

Two rural hospitals' projects apply swing bed concept successfully

Alternating beds between acute and long term care may save rural hospitals from unnecessary closing and alter the balance of services to meet demand. The swing bed concept--subject of two experimental programs in Utah, Texas, South Dakota, and Iowa--may be applicable nationwide.

Hydrogen evolution and uptake by nodules of soybeans inoculated with different strains of Rhizobium japonicum

Hydrogen evolved by nitrogenase may be recycled by a hydrogenase present in some legume nodules. Anoka and Portage cultivars of soybeans were inoculated with each of 8 and 24 strains, respectively, of Rhizobium japonicum and surveyed for H2 evolution and C2H2 reduction rates nodule weight, and plant dry weight. Six of the strains (3Ilb 110, USDA 122, USDA 136, 3Ilb 6, 3Ilb 142, and 3Ilb 143) which exhibited no H2 evolution in air were shown to take up H2. The relative efficiencies of nitrogenase energy utilization based on C2H2 reduction rates of nodules relative efficiences of nitrogenase energy utilization based on C2H2 reduction rates of nodules ranged from 0.96 to 1.0 for the six strains. Nodules formed by strain WA 5099-1-1 evolved small amounts of H2 in air and had a relative efficiency of 0.92. Nodules formed by the remaining 25 strains had relative efficiencies ranging from 0.41 to 0.80. A H2-evolving (3Ilb 123) and non-H2-evolving (3Ilb 143) strain were tested on seven soybean cultivars to determine the effect on the expression of hydrogenase. Nodules formed by strain 3Ilb 143 exhibited an efficiency of 1.0 on the following cultivars: Amsoy 71, Anoka, Bonus, Clark 63, Kent, Peking, and Portage. Relative efficiencies from 0.63 to 0.77 were determined for the five cultivars nodulated by strain 3Ilb 123. From the experiments with these cultivars, the capacity to recycle H2 produced from the nitrogenase system appears to be determined by the R. japonicum strain.

Isolation of amylolytic system of Aspergillus oryzae by sorption on DEAHP amylum

Conditions of effective sorption of amylolytic enzyme from a solution or from fermentative liquid on DEAHP amylum were studied. Isolating action is in a direct dependence on the relation between activity and amount of DEAHP amylum, the curve of this dependence was illustrated. The enzyme can be released by elution or adsorbate can be used in a pulverised from. In the conclusion of the work laboratory isolation technique is described.