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At least 91 records · Page 5Linked to original sources
PubMed2001

Singlet oxygen induces oxidation of cellular DNA.

The aim of the present work was to evaluate the potential for (1)O(2) to induce oxidation of cellular DNA. For this purpose cells were incubated in the presence of a water-soluble endoperoxide whose thermal decomposition leads to the formation of singlet oxygen. Thereafter, DNA was extracted and the level of several modified DNA bases was determined by HPLC analysis coupled to a tandem mass spectrometric detection. A significant increase in the level of 8-oxo-7,8-dihydro-2'-deoxyguanosine was observed upon incubation of the cells with the chemical generator of (1)O(2), whereas the level of the other DNA bases measured remained unchanged. To demonstrate that singlet oxygen is directly involved in the formation of 8-oxo-7, 8-dihydro-2'-deoxyguanosine, the corresponding (18)O-labeled endoperoxide was used. Incubation of the cells with such a generator of (18)O-labeled singlet oxygen results in the formation of (18)O-labeled 8-oxo-7,8-dihydro-2'-deoxyguanosine in the nuclear DNA. This result clearly demonstrates that singlet oxygen, when released within cells, is able to directly oxidize cellular DNA.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Cellular distribution and handling of liver-targeting preparations in human livers studied by a liver lobe perfusion.

We developed and tested a novel method for perfusing parts of human liver to study uptake and handling of drug-targeting preparations. These preparations, designed for the treatment of liver fibrosis in man, have been extensively studied in animals, but little is known about the uptake and handling by human livers. Human liver tissue was obtained from livers procured from multiorgan donors and from cirrhotic livers of patients. To assess tissue viability, perfusate glutamate-oxalacetate-transaminase (GOT), glutamate-pyruvate-transaminase (GPT), and lactate dehydrogenase (LDH) levels were determined. To assess tissue functionality, the uptake of taurocholic acid and phase I and II metabolism of lidocaine and 7-hydroxycoumarin were determined. Uptake of a drug-targeting preparation was studied with Dexa(10)-HSA, which is designed for targeting of dexamethasone to nonparenchymal cells in the liver. During a 90-min perfusion period, no elevation of either GOT, GPT, or LDH was found. Both healthy control livers and cirrhotic livers showed phase I and II drug metabolism and functional taurocholic acid uptake. Studies with Dexa(10)-HSA revealed that 60 min after administration, 40% of the dose had been taken up by control livers and only 5% by cirrhotic livers. In control livers, Kupffer and endothelial cells had taken up Dexa(10)-HSA, whereas in cirrhotic livers only Kupffer cells were responsible for the uptake. Viability parameters and liver function tests clearly showed the applicability of this method. In the perfusion set-up, we showed uptake of the drug-targeting preparation Dexa(10)-HSA by healthy and cirrhotic human liver tissue, although the distribution patterns differed. This demonstrates the need to study new concepts in (diseased) human tissue.

Anesthetics, Local↗
PubMed2002

Visualisation of diverticula of the upper part of the alimentary tract; comparison of roentgenologic and endoscopic techniques.

Diverticula of the upper part of the alimentary tract, irrespective of their etiology, are frequently observed benign changes of the pharynx, oesophagus, stomach and duodenum. In the present work, patients of the II General Surgery Department of the Medical University of Lublin, with radiologically or endoscopically proved diverticula of the upper part of the alimentary tract, were examined. The presence of diverticula of such localisation was an indication for supplementary endoscopic or radiological examination. The localisation, size, diameter of the opening, mucosal relief of diverticula and its contiguity were checked and analysed. Our data suggest that both medical procedures are complementary to each other. All previously observed changes in diverticula of the thoracic part of the oesophagus and the infradiaphragm part of the alimentary tract were fully proved. The radiological examination gave a better view of Zenker's diverticulum, especially in short and obese patients. Sampling and better visualisation of the diverticula opening testify to the unquestionable superiority of endoscopy. However, precise evaluation by radiological process fully completes the diagnostic protocol. Both diagnostic procedures are usually supplemented by manometric examination of the oesophagus and superior and inferior oesophageal sphincters. This enables the accurate diverticula etiology to be stated.

Diverticulum, Esophageal↗
PubMed2002

Comparison between caloric and canal impulse rotatory test.

It has been suggested that the rotatory test using videonystagmoscopy can also be applied for identification of vestibular canal paresis. In this study, we test this hypothesis by comparing the results of a canal impulse rotatory test with those of the caloric test using the method described by Freyss. Our study indicates that only in 38% of all tested patients, the same results between the two tests have been obtained. Furthermore, when the group with abnormal findings is observed separately, in 24% patients only these two test methods lead to the same results. Consequently, the canal impulse rotatory test cannot replace the caloric test.

Caloric Tests↗
PubMed2002

Early depictions of the nasal turbinates in the 15th century.

Although nasal turbinates had already been described by Hippocrates, it was not until the 15th century that they were depicted. The inferior turbinate was shown for the first time rather true-to nature in the works of the Middle Rhenic Master circa 1450-1460 and Leonardo da Vinci in 1489. The posterior ends of the middle turbinates were depicted on a woodcut by Georg Thomas for Dryander's "Anatomiae ... pars prior" in 1536. These and a few other examples show that some artists were ahead of the medical profession in demonstrating anatomical details in the 15th and 16th century.

History, 15th Century↗
PubMed1992

Evidence for a 5-HT1-like receptor mediating the amplifying action of 5-HT in the rabbit ear artery.

1. The nature of the 5-hydroxytryptamine (5-HT) receptors which amplify the vasoconstrictor effect of methoxamine was examined in the rabbit isolated perfused ear artery with intact endothelium. Indices of amplification were leftward shifts of methoxamine dose-response (DR) curves produced by 5-HT (0.3 microM) (Method I), and the appearance of vasoconstrictor responses to 5-HT receptor agonists when methoxamine was present in a near-threshold concentration (Method II). 2. The amplifying effect of 5-HT (Method I) was unaffected by prazosin (0.08 microM), was partly depressed by 5-HT2-receptor antagonists in high concentrations (ketanserin 0.5 microM, LY53857, 1.0 microM), and was abolished by a non-selective antagonist of 5-HT1 and 5-HT2 receptors (methiothepin, 0.01 microM). 3. Amplifying potencies of agonists assessed by both Methods I and II were in the order 5-carbox-amidotryptamine (5-CT) greater than 5-HT greater than alpha-methyl 5-HT. The potency of sumatriptan (assessed by Method II only) was intermediate between those of 5-HT and alpha-methyl 5-HT. 4. Ketanserin and LY53857 inhibited the amplifying action of 5-CT to about the same extent as that of 5-HT. 5. The amplifying potencies of the agonists are in marked contrast to the reported contractile potencies in the rabbit aorta where the receptor is 5-HT2, but are almost identical with reported contractile potencies in the dog saphenous vein where the receptor is 5-HT1-like. 6. It is concluded that a 5-HT,-like receptor mediates the amplifying interaction between 5-HT and methoxamine in the rabbit ear artery which can be weakly blocked by ketanserin and LY53857.7. Since 5-CT was equipotent when applied separately to the intimal and adventitial surfaces of the artery, it is suggested that the 5-HT,-like receptors are distributed uniformly across the artery wall.

Acetylcholine↗
PubMed2003

Regulation of cyclic adenosine 3',5'- monophosphate signaling and pulsatile neurosecretion by Gi-coupled plasma membrane estrogen receptors in immortalized gonadotrophin-releasing hormone neurons.

Immortalized GnRH neurons (GT1-7) express receptors for estrogen [estrogen receptor-alpha and-13(ERa and ERI3)] and progesterone (progesterone receptor A) and exhibit positive immunostaining for both intracellular and plasma membrane ERs. Exposure of GT1-7 cells to picomolar estradiol concentrations for 5-60 min caused rapid, sustained,and dose-dependent inhibition of cAMP production. In contrast, treatment with nanomolar estradiol concentrations for 60 min increased cAMP production. The inhibitory and stimulatory actions of estradiol on cAMP formation were abolished by the ER antagonist, ICI 182,780. The estradiol-induced inhibition of cAMP production was prevented by treatment with pertussis toxin, consistent with coupling of the plasma membrane ER to an inhibitory G protein. Coimmunoprecipitation studies demonstrated an estradiol-regulated stimulatory interaction between ERa and G,3 that was prevented by the ER antagonist, ICI 182,780. Exposure of perifused GT1-7 cells and hypothalamic neurons to picomolar estradiol levels increased the GnRH peak interval, shortened peak duration, and increased peak amplitude. These findings indicate that occupancy of the plasma membrane-associated ERs expressed in GT1-7 neurons by physio-logical estradiol levels causes activation of a G, protein and modulates cAMP signaling and neuropeptide secretion.

Animals↗
PubMed2004

Microbioreactor arrays with parametric control for high-throughput experimentation.

A scalable array technology for parametric control of high-throughput cell cultivations is demonstrated. The technology makes use of commercial printed circuit board (PCB) technology, integrated circuit sensors, and an electrochemical gas generation system. We present results for an array of eight 250 microl microbioreactors. Each bioreactor contains an independently addressable suite that provides closed-loop temperature control, generates feed gas electrochemically, and continuously monitors optical density. The PCB technology allows for the assembly of additional off-the-shelf components into the microbioreactor array; we demonstrate the use of a commercial ISFET chip to continuously monitor culture pH. The electrochemical dosing system provides a powerful paradigm for reproducible gas delivery to high-density arrays of microreactors. Growth data are presented for Escherichia coli cultured in the array with varying microaerobic conditions using electrochemically generated oxygen. Additionally, we present data on carbon dioxide generation for pH dosing.

Bioreactors↗
PubMed2004

A proteomics approach to characterizing tick salivary secretions.

The saliva of ticks contains a complex mixture of bioactive molecules including proteins that modulate host responses ensuring successful feeding. The limited amount of saliva that can be obtained from ticks has hampered characterization of salivary proteins using traditional protein chemistry. Recent improvements in two-dimensional gel electrophoresis, mass spectrometry, and bioinformatics provide new tools to characterize small amounts of protein. These methods were employed to characterize salivary proteins from Amblyomma americanum and Amblyvomma maculatum. Salivation was induced by injection of dopamine and theophylline. It was necessary to desalt and concentrate saliva before analysis by 2-D electrophoresis. Comparison of 1-D and 2-D gel patterns revealed that the major protein component of saliva did not appear on 2-D gels. Characterization of this protein showed that it was identical to the major protein present in the hemolymph of both tick species. Protein profiles obtained by 1-D and 2-D gel electrophoresis were similar for both tick species, however, higher concentrations of lower molecular weight proteins were present in A. maculatum. Protein analysis by MALDI-TOF mass spectrometry and western blot analysis showed that except for the most abundant protein with a molecular weight of 95 kDa, all of the proteins detected were of host origin. It is not known if this is an artifact of the collection method or has physiological significance. In either case, in these species of ticks, host proteins will have to be removed from saliva samples prior to 2-D analysis in order to characterize lower abundance proteins of tick origin.

Animals↗
PubMed2004

Decreased survival of B cells of HIV-viremic patients mediated by altered expression of receptors of the TNF superfamily.

Human immunodeficiency virus (HIV) infection leads to numerous perturbations of B cells through mechanisms that remain elusive. We performed DNA microarray, phenotypic, and functional analyses in an effort to elucidate mechanisms of B cell perturbation associated with ongoing HIV replication. 42 genes were up-regulated in B cells of HIV-viremic patients when compared with HIV-aviremic and HIV-negative patients, the majority of which were interferon (IFN)-stimulated or associated with terminal differentiation. Flow cytometry confirmed these increases and indicated that CD21(low) B cells, enhanced in HIV-viremic patients, were largely responsible for the changes. Increased expression of the tumor necrosis factor (TNF) superfamily (TNFSF) receptor CD95 correlated with increased susceptibility to CD95-mediated apoptosis of CD21(low) B cells, which, in turn, correlated with HIV plasma viremia. Increased expression of BCMA, a weak TNFSF receptor for B lymphocyte stimulator (BLyS), on CD21(low) B cells was associated with a concomitant reduction in the expression of the more potent BLyS receptor, BAFF-R, that resulted in reduced BLyS binding and BLyS-mediated survival. These findings demonstrate that altered expression of genes associated with IFN stimulation and terminal differentiation in B cells of HIV-viremic patients lead to an increased propensity to cell death, which may have substantial deleterious effects on B cell responsiveness to antigenic stimulation.

Apoptosis↗
PubMed2006

Mechanical coil embolization of pulmonary arteriovenous malformations.

PURPOSE: To report our experience with mechanical coil embolization of pulmonary arteriovenous malformations. MATERIAL AND METHODS: Coil embolization was performed in 6 men (mean age, 21.1 years; age range, 20-23 years) with pulmonary arteriovenous malformations between 1999 and 2004. Five F Cobra catheters and various sized coils were used for embolization. Clinically, cases were followed-up every 3 months for one year and every 6 months thereafter, with a mean total follow-up period of 2.3 years. RESULTS: Complete primary occlusion was achieved in all patients. There were no complications related to the procedure and no problems were reported during follow-up period. CONCLUSION: Treatment of pulmonary arteriovenous malformation cases with coil embolization is an effective option.

Adult↗
PubMed2005

Penetrating type intraosseous ganglion cyst of the lunate bone.

Intraosseous ganglion cysts of the carpal bones located in the lunate are one of the rarely seen pathologic conditions. Here we present a case of the penetrating type of intraosseous ganglion cyst located in the lunate as an uncommon cause of wrist pain. The patient was successfully treated by surgical intervention. Intraosseous ganglion cyst should be considered in the differential diagnosis of chronic dull wrist pain.

Adult↗
PubMedDate not supplied

[Histochemical study of elastic system fibers of the walls of normal and pathological saphenous veins].

Normal, varicose and phlebitic saphenous veins were studied by histochemical methods to establish the qualitative variations of their structural components. The histologic preparations were stained by hematoxylin-eosin Gomori's trichrome, orcinol-neofuchsin and resorcin-fuchsin. Normal saphenous vein showed two layers of smooth muscle cells--an internal circular and an external longitudinal. The components of the elastic system were found in the three layers. Elastic fibers were present in the adventitia under an elongated and wavy conformation. In the media they were present in the external portion. Elaunin fibers were found in the media and intima. The oxytalan fibers were not consistently found. The media and intima of varicose veins showed contracted smooth muscle cells associated with fragmented elastic fibers and augmentation of elaunin fibers. In cases of thrombophlebitis the same alterations observed in varicose veins were found together with a decrease of elastic system fibers in the media and intima. The muscle cells showed a loss of their morphologic characteristics.

Contractile Proteins↗
PubMed1991

Combination of an antiandrogen and a 5 alpha-reductase inhibitor: a further step towards total androgen blockade?

While the elimination of androgens of testicular origin can be easily achieved by orchiectomy or medical castration with LHRH agonists, the action of adrenal androgen precursors which are converted into the active androgen 5 alpha-dihydrotestosterone (DHT) in the prostatic tissue itself can be partially neutralized by antiandrogens which compete with DHT for binding to the androgen receptor. In order to increase the efficiency of androgen blockade, we have used 4-MA, an inhibitor of 5 alpha-reductase, the enzyme which converts testosterone into DHT, to reduce intracellular DHT concentrations and thus facilitate the action of the antiandrogen Flutamide. The present data show that the inhibitory effects of 4-MA (17 beta, N,N-diethylcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one) and of the antiandrogen Flutamide are additive on prostatic growth and on androgen-sensitive prostatic binding protein mRNA levels in the rat, thus clearly suggesting that such a combination could provide the basis for a further improvement in the therapy of prostate cancer.

5-alpha Reductase Inhibitors↗
PubMed1990

Ambulatory care. An objective assessment.

Budget constraints, loss of staff, and the inability of administrators to define nursing needs in the outpatient department lead to the development of a tool to define the role of the healthcare provider in the outpatient department. The author discusses the tool's use in categorizing and quantifying nursing activities. Administrators in ambulatory care now have an opportunity to use this readily adaptable method in their outpatient areas to assist in developing quality, cost-effective nursing.

Ambulatory Care↗