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At least 613 records · Page 34Linked to original sources
PubMed2005

Altered endothelial function in isolated human myometrial vessels induced by plasma from women with pre-eclampsia is not reproducible in isolated mouse vessels.

In order to facilitate characterization of the circulating factor(s) in pre-eclampsia, the present study aimed to determine whether plasma from women with pre-eclampsia, which induces attenuated endothelial-dependent relaxation in human myometrial arteries, is also capable of inducing altered endothelial function in mouse vessels. Human vessels were isolated from myometrial biopsies taken from women with uncomplicated pregnancies (n = 6). Mesenteric and uterine arteries were isolated from male, female, non-pregnant and pregnant C57B mice (n = 24). Vessels were studied using a wire myograph and incubated with plasma (2%) from women with pre-eclampsia (n = 12) or controls (n = 12). Incubation of myometrial vessels from normal pregnant women with plasma from women with pre-eclampsia reduced endothelial-dependent relaxation. This effect was not reproduced in male or female mouse mesenteric or uterine vessels incubated with plasma from women with pre-eclampsia. In conclusion, there are species-specific differences in the actions of the circulating factor(s) on endothelial-dependent relaxation of human and mouse small arteries.

Adult↗
PubMed1998

Multidrug resistance-related transport proteins in isolated human brain microvessels and in cells cultured from these isolates.

The multidrug transporter, P-glycoprotein (Pgp), at the blood-brain barrier is thought to be important for limiting access of toxic agents to the brain, but controversy surrounds its cellular location, whether on endothelium or on adjacent astrocyte foot processes. In the present study, the distribution of protein and mRNA for Pgp and for another transporter, multidrug resistance-associated protein (MRP), is compared with that for the endothelial marker, platelet-endothelial cell adhesion molecule-1 (PECAM-1) and for the astrocyte-derived glial fibrillary acidic protein (GFAP) in microvessels isolated from human brain and in cells grown from these microvessels. Activities of the multidrug transporters are assessed in the cultured cells from the effects of transport inhibitors on intracellular [3H]vincristine accumulation. The isolated microvessels show strong immunocytochemical staining for Pgp and PECAM-1 and little or no staining for GFAP and MRP, and they contain mRNAs detectable by RT-PCR encoding only Pgp and PECAM-1, but not GFAP or MRP. Thus, Pgp may well be synthesised and expressed on cells within the microvessels rather than on adherent astrocyte foot processes. In cells grown from the microvessels, although PECAM-1 remains, Pgp expression decreases and MRP appears. Evidence suggests these multidrug transporters are functionally active in the cultured cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2006

The primary amine metabolite of sibutramine stimulates lipolysis in adipocytes isolated from lean and obese mice and in isolated human adipocytes.

Sibutramine is a satiety-inducing serotonin-noradrenaline reuptake inhibitor that acts predominantly via its primary and secondary metabolites. This study investigates the possibility that sibutramine and/or its metabolites could act directly on white adipose tissue to increase lipolysis. Adipocytes were isolated by a collagenase digestion procedure from homozygous lean (+/+) and obese-diabetic OB/OB mice, and from lean nondiabetic human subjects. The lipolytic activity of adipocyte preparations was measured by the determination of glycerol release over a 2-hour incubation period. The primary amine metabolite of sibutramine M2, caused a concentration-dependent stimulation of glycerol release by murine lean and obese adipocytes (maximum increase by 157+/-22 and 245+/-16%, respectively, p<0.05). Neither sibutramine nor its secondary amine metabolite M1 had any effect on lipolytic activity. Preliminary studies indicated that M2-induced lipolysis was mediated via a beta-adrenergic action. The non-selective beta-adrenoceptor antagonist propranolol (10 (-6) M) strongly inhibited M2-stimulated lipolysis in lean and obese murine adipocytes. M2 similarly increased lipolysis by isolated human omental and subcutaneous adipocytes (maximum increase by 194+/-33 and 136+/-4%, respectively, p<0.05) with EC50 values of 12 nM and 3 nM, respectively. These results indicate that the sibutramine metabolite M2 can act directly on murine and human adipose tissue to increase lipolysis via a pathway involving beta-adrenoceptors.

Adipocytes↗
PubMed1988

Inhibition by salicylates of urea synthesis by isolated rat hepatocytes and citrulline synthesis by isolated rat mitochondria: an effect independent of uncoupling.

1. Acetylsalicylate and salicylate inhibited urea synthesis by isolated rat hepatocytes and citrulline synthesis by isolated rat mitochondria. The effects were dose-dependent and occurred at drug concentrations seen in salicylate induced hepatoxicity. 2. Although ATP concentration was decreased in the hepatocytes the effect of the salicylates on citrulline synthesis remained after treatment with oligomycin and carbonyl cyanide m-chlorophenyl hydrazone. This suggests that the effect is independent of uncoupling of oxidative phosphorylation. 3. This in vitro inhibition of urea synthesis by salicylates is similar to that produced by valproate and endogenous organic acids, which are also associated with hyperammonaemic clinical toxicity, and is a possible mechanism for the action of salicylates in the hyperammonaemia of Reye's syndrome.

Animals↗
PubMed1998

Endogenous or overexpressed cGMP-dependent protein kinases inhibit cAMP-dependent renin release from rat isolated perfused kidney, microdissected glomeruli, and isolated juxtaglomerular cells.

An overactive renin-angiotensin-aldosterone system (RAAS) has a central role in the pathogenesis of hypertension and cardiac hypertrophy, precursors of cardiac failure. Natriuretic peptides and NO acting through their second messenger, cGMP, increase natriuresis and diuresis, and inhibit renin release; however the mechanism by which this inhibition of the RAAS system functions is obscure. We recently reported cloning of the cDNA for type II cGMP-dependent protein kinase (cGK II), elucidated its first known function of inhibiting the cystic fibrosis transmembrane conductance regulator in rat intestine, and initially described its location in rat kidney juxtaglomerular (JG) cells, the ascending thin limb, and the brush border of proximal tubules. Here, we demonstrate inhibition of isoproterenol- or forskolin-stimulated renin release by 8-para-chlorophenylthio-cGMP (8-pCPT-cGMP), a selective activator of cGK, and prevention of this inhibition by a selective inhibitor of cGK, Rp-8-pCPT-cGMPS. In systems of differing complexity, inhibition by 8-pCPT-cGMP was nearly complete in isolated perfused kidney and microdissected afferent arterioles but only approximately 25% in isolated JG cells. Expression of either cGK II or cGK I in JG cells by using adenoviral vectors enhanced the inhibition of forskolin-stimulated renin release by 8-pCPT-cGMP to 50%. Our results indicate that cGK II, and possibly cGK I, can mediate cGMP inhibitory effects on renin release and are physiological components of the cGMP signal transduction system which opposes the RAAS.

Animals↗
PubMed2004

Have South Australian isolates of Neisseria meningitidis become less susceptible to penicillin, rifampicin and other drugs? A study of strains isolated over three decades, 1971-1999.

AIMS: To ascertain whether isolates of Neisseria meningitidis in South Australia (SA) have become less susceptible to antimicrobial agents. The patients studied were children and adults in SA with either meningococcal bacteraemia or meningitis or both. METHODS: The susceptibility of meningococci to 11 antimicrobial agents, including sulphonamides, penicillin and rifampicin, was tested by agar dilution, and in the case of six of the drugs, by E test also. RESULTS: Resistance to folate antagonists emerged in 1979 and became very common. Resistance peaked in 1995 at 76% of strains. Relative insusceptibility to penicillin was first encountered amongst strains isolated in 1985, and, while the incidence of such strains increased slightly, the overall incidence was low at 10 (5.2%) of 190 strains tested. Meningococci relatively insusceptible to rifampicin were encountered as early at 1971 and did not become more common. The incidence of such strains at 26 (13.7%) of 189 strains tested was higher than that for penicillin. For the 11-year period 1989-1999 of > or= 84 strains tested all were susceptible to ceftriaxone, chloramphenicol and ciprofloxacin; 98% were susceptible to azithromycin and 97% were susceptible to minocycline. Shifts in MIC values for these drugs were not detected. CONCLUSIONS: Resistance was common to sulphonamides and co-trimoxazole, however >or=95% meningococci tested were susceptible to drugs commonly used in the treatment of meningococcal disease, including penicillin and ceftriaxone. Relative insusceptibility to rifampicin was more common but did not increase during the 29-year period. For all drugs tested, except rifampicin, there was good agreement between agar dilution and E test results.

Aged↗
PubMed1988

The detection of Mycobacterium paratuberculosis in bovine faeces by isolation and the comparison of isolation with the examination of stained smears by light microscopy.

The detection of Mycobacterium paratuberculosis organisms in bovine faeces by isolation was compared with that by the microscopical examination of Ziehl-Neelsen stained faecal smears for the presence of clumps of acid-fast M. paratuberculosis organisms. Faeces were obtained from cattle naturally or experimentally infected with M. paratuberculosis as well as from uninfected cattle. Microscopical examination was an unreliable method for the detection of M. paratuberculosis organisms, since the organisms were only detected in 99 (=55.9%) of 177 culturally positive faecal samples. 1111 addition, clumps of acid-fast organisms indistinguishable from M. paratuberculosis were also observed iin three of 18 samples from cattle free from Johne's disease and in 18 of 37 culturally negative samples from paratuberculous cattle. When M. paratuberculosis organisms were added to faeces from an uninfected cow, results showed that isolation attempts should be positive when 15 or more M. paratuberculosis organisms per gram of faeces are present.

Journal Article↗
PubMed1999

Isolation and characterization of an arginine ester hydrolase from Bothrops jararacussu venom which induces contractions of the isolated rat uterus.

The isolation and partial characterization of a serine protease with arginine ester hydrolase activity from Bothrops jararacussu snake venom are described. The purification procedure consisted of a gel filtration of the crude venom on Sephadex G-75 followed by an ion-exchange chromatography of the active fraction on DEAE-cellulose and a rechromatography on Bio-Rex 70 resin. The esterase fraction (DI-III), M(r) = 25,000 by SDS-PAGE, showed proteolytic activity on fibrinogen and casein. After 2 hr incubation, the A alpha and B beta chains of fibrinogen were intensely hydrolysed, while the gamma chain kept apparently intact, even after 20 hr of incubation. In spite of that, DI-III did not clot fibrinogen. DI-III induced edema in the rat paw. Although unable to release bradykinin, it induced contractions of the isolated rat uterus. DI-III did not catalyse the hydrolysis of bradykinin. Its arginine ester hydrolase activity was completely inhibited by diisopropyl fluorophosphate after 1 hr incubation, but not by phenylmethylsulfonyl fluoride under the same conditions.

Animals↗
PubMed1963

STUDIES ON ISOLATED NUCLEI. II. ISOLATION AND CHEMICAL CHARACTERIZATION OF NUCLEOLAR AND NUCLEOPLASMIC SUBFRACTIONS.

This paper describes the subfractionation of nuclei isolated from guinea pig liver by the procedure presented in the first article of the series (8). Centrifugation in a density gradient system of nuclear fractions disrupted by sonication permits the isolation of the following subfractions: (a) a nucleolar subfraction which consists mainly of nucleoli surrounded by a variable amount of nucleolus-associated chromatin and contaminated by chromatin blocks derived primarily from von Kupffer cell nuclei; (b) and (c), two nucleoplasmic subfractions (I and II) which consist mainly of chromatin threads in a coarser (I) or finer (II) degree of fragmentation. The protein, RNA, and DNA content of these subfractions was determined, and their RNA's characterized in terms of NaCl-solubility, nucleotide composition, and in vivo nucleotide turnover, using inorganic (32)P as a marker. The results indicate that there are at least three types of RNA in the nucleus (one in the nucleolus and two in the nucleoplasm or chromatin), which differ from one another in NaCl-solubility, nucleotide composition, turnover, and possibly sequence. Possible relations among these RNA's and those of the cytoplasm are discussed.

Animals↗
PubMed1969

Isolation and properties of secretory granules from rat islets of Langerhans. I. Isolation of a secretory granule fraction.

A method has been devised for the isolation of a secretory granule fraction from isolated rat islets of Langerhans. The islets were homogenized in buffered sucrose, and the homogenate was separated into nuclear, mitochondrial, secretory granule, and microsomal fractions by differential centrifugation. The secretory granule fraction was purified by differential centrifugation in discontinuous sucrose density gradients. A greater degree of purification could be achieved by the use of two successive gradients of this type, although the final yield was greatly reduced. Biochemical and morphological characterization of the fractions was obtained; the secretory granule fraction contained both insulin and glucagon. The limiting membranes of the granules remained intact and the general appearance of the granules was similar to that seen within the whole islet cells.

Animals↗
PubMed1969

Isolation and properties of secretory granules from rat islets of Langerhans. 3. Studies of the stability of the isolated beta granules.

A partially purified secretory granule fraction, isolated from rat islets of Langerhans by differential centrifugation, was used for investigating the stability of the beta granules during incubation in various conditions. Effects of pH, temperature, and time were studied; the granules possessed optimal stability at 4 degrees and pH 6.0, and could be solubilized at pH 4.0 or 8.5, or in the presence of sodium deoxycholate, but not by phospholipase c, ouabain, or alloxan. Incubation with glucose or some of its metabolites, or with tolbutamide, ATP, or cyclic 3',5'-AMP did not alter the stability of the beta granules Exogenous insulin-(131)I was not bound by the isolated granules under the conditions used; no specific insulin-degrading activity could be detected in subcellular fractions of the islets. These findings indicate that intracellular solubilization of the granules with subsequent diffusion of the insulin into the extracellular space is not a likely mode of insulin secretion in vivo, and suggest that a crystalline zinc-insulin complex may exist in the matrix of the beta granules.

Animals↗
PubMed2000

Comparison of Vpu sequences from diverse geographical isolates of HIV type 1 identifies the presence of highly variable domains, additional invariant amino acids, and a signature sequence motif common to subtype C isolates.

We compared the Vpu sequences from 101 strains of HIV-1 isolated from diverse geographical regions and various subtypes in order to identify regions of high variability, and those amino acid residues that were highly conserved or invariant. In addition to the highly conserved casein kinase II (CKII) phosphorylation sites, our analysis identified additional invariant residues in the transmembrane domain and in the first and second alpha-helical domains. Our analysis revealed that all subtype C sequences had a conserved LRLL motif at the C terminus that was also found in A/C intersubtype recombinants. While our analysis demonstrated the conservation of CKII domains in HIV-1 group M and O isolates, the number of potential CKII phosphorylation sites was variable in SIVcpz sequences. The results of this study will provide a basis for future mutagenesis studies to examine the role of certain amino acid residues in the structure and function of Vpu.

Amino Acid Motifs↗
PubMed2001

In vitro activity of cefditoren against clinical isolates of penicillin-susceptible and penicillin-intermediate strains of Streptococcus pneumoniae isolated in Germany, 1992-1998.

This study investigates the susceptibility to cefditoren of penicillin-susceptible strains of invasive Streptococcus pneumoniae (n = 312) and of penicillin-intermediate strains of S. pneumoniae (n = 30) isolated mainly from patients with respiratory tract infections. The MIC(90)s of penicillin-susceptible and -intermediate isolates were as follows: cefditoren, < or =0.06 and 1 mg/L; penicillin G, < or =0.06 and 0.5 mg/L. Cefditoren showed the highest activity against the penicillin-intermediate strains investigated compared with the other beta-lactam antibiotics and is therefore considered to be a promising agent for the treatment of infections caused by pneumococci with reduced penicillin susceptibility.

Cephalosporins↗
PubMed1982

Isolation of two inactive fragments of a Rhizopus sp. glucoamylase: relationship among three forms of the enzyme and the isolated fragments.

Two inactive fragments of glucoamylase [EC 3.2.1.3] from a Rhizopus sp. were isolated from the glucoamylase fraction obtained by CM-Sephadex chromatography in the previous purification of the glucoamylase (T. Takahashi et al. (1978) J. Biochem. 84, 1183-1194); the fraction contained at most 2.5% of the fragments, besides a mixture (97.5%) of three glucoamylases, designated as Gluc1 (M.W. 74,000), Gluc2 (M.W. 58,600), and Gluc3 (M.W. 61,400) in order of content. The two isolated fragments, named fragments H and L in order of size, were found to be homogeneous in polyacrylamide gel electrophoresis, isoelectric focusing, and ultracentrifugation analysis. The molecular weights of fragments H and L were 16,700 and 14,400, respectively. Fragment H had alanine as its N-terminal residue although fragment L was heterogeneous at the N-terminal amino acid. The N-terminal amino acids of Gluc1, Gluc2, and Gluc3 were found to be alanine, glutamic acid, and lysine, respectively; the three enzymes had the same C-terminal amino acid sequence of -Ser-Ala . OH. Immunodiffusion demonstrated that both fragments cross-reacted with Gluc1 and Gluc3 but not with Gluc2, although the three enzymes had common antigenicity. These results, together with the amino acid and sugar compositions of the fragments, indicate that the two fragments were derived from the N-terminal glycopeptide moiety of Gluc1 by the action of a proteolytic enzyme(s) with concomitant formation of Gluc2; Gluc3 also seems to be produced by proteolytic modification of Gluc1 with loss of its N-terminal peptide moiety.

Amino Acids↗
PubMed2006

Prenatal intervention for isolated congenital diaphragmatic hernia.

PURPOSE OF REVIEW: We aim to review the recent literature regarding early prenatal prediction of outcome in babies diagnosed with isolated congenital diaphragmatic hernia, as well as results of fetal therapy for this condition. RECENT FINDINGS: Current survival rates in population-based studies are around 55-70%. Highly specialized centers report 80% and more, but discount the hidden mortality, mainly in the antenatal period. Fetuses presenting with liver herniation and a lung-to-head ratio of less than 1.0 measured in midgestation have a poor prognosis. Other volumetric techniques are being evaluated for use in midtrimester. Recently, a randomized trial failed to show benefit from prenatal therapy, but lacked power to document the potential advantage of prenatal therapy in severe cases. We proposed percutaneous fetal endoluminal tracheal occlusion with a balloon at 26-28 weeks through a 3.3 mm incision. In severe cases, fetal endoluminal tracheal occlusion increased lung size as well as survival, with an early (7 day) survival, late neonatal (28 day) survival and survival at discharge of 75, 58 and 50%, respectively, comparing favorably with 9% in contemporary controls. Airways can be restored prior to birth improving neonatal survival (83.3% compared with 33.3%). The procedure carries a risk for preterm prelabour rupture of the fetal membranes, although that may decrease with experience. SUMMARY: Fetuses with severe congenital diaphragmatic hernia can be identified in the second trimester. Fetal endoluminal tracheal occlusion can be considered as a minimally invasive fetal therapy, improving outcome in such highly selected cases.

Female↗
PubMed1992

A 1.5 kb sequence homology in 3'-terminal regions of RNA-1 and RNA-2 of a birch isolate of cherry leaf roll nepovirus is also present, in part, in a rhubarb isolate.

A series of cDNA clones has been made from the birch isolate of cherry leaf roll nepovirus. Restriction enzyme analysis and sequencing showed that at the 3' end, RNA-1 and RNA-2 are identical for 1.5 kb. Also a 0.7 kb 3' end homology exists between the birch and rhubarb isolate. These sequences do not seem to code for any proteins; however, the sequence conservation points to a role in virus replication.

Base Sequence↗
PubMed2006

FAIRE (Formaldehyde-Assisted Isolation of Regulatory Elements) isolates active regulatory elements from human chromatin.

DNA segments that actively regulate transcription in vivo are typically characterized by eviction of nucleosomes from chromatin and are experimentally identified by their hypersensitivity to nucleases. Here we demonstrate a simple procedure for the isolation of nucleosome-depleted DNA from human chromatin, termed FAIRE (Formaldehyde-Assisted Isolation of Regulatory Elements). To perform FAIRE, chromatin is crosslinked with formaldehyde in vivo, sheared by sonication, and phenol-chloroform extracted. The DNA recovered in the aqueous phase is fluorescently labeled and hybridized to a DNA microarray. FAIRE performed in human cells strongly enriches DNA coincident with the location of DNaseI hypersensitive sites, transcriptional start sites, and active promoters. Evidence for cell-type-specific patterns of FAIRE enrichment is also presented. FAIRE has utility as a positive selection for genomic regions associated with regulatory activity, including regions traditionally detected by nuclease hypersensitivity assays.

Cells, Cultured↗
PubMed1995

Isolation of Coxiella burnetii from dairy cattle and ticks, and some characteristics of the isolates in Japan.

Coxiella burnetii was isolated from raw milk (36/214, 16.8%) and uterus swab samples (13/61, 21.3%) originating from dairy cattle with reproductive disorders, aborted bovine fetus samples (2/4, 50%), mammary gland samples (4/50, 8%) originating from healthy dairy cattle, and tick samples (4/15, 26.7%) originating from 2 pastures. Fifty-nine strains had various degrees of pathogenicity, high (8; 13.6%), moderate (28; 47.5%) and low (23; 39%), for guinea pigs. The results of isolation suggested a high prevalence of Coxiella infection in dairy cattle with reproductive problems in Japan. Twelve strains (7, 2 and 3 strains from cattle, ticks and humans, respectively) and the reference Nine Mile strain of phases I and II were propagated in both yolk sacs of embryonated hen eggs and Buffalo green monkey (BGM) cell cultures. Protein profiles of these strains were similar to those of the reference strain of phase I. Lipopolysaccharide (LPS) profiles of 12 strains were similar to those of the reference strain of phase I and different from those of the reference strain of phase II. The LPS profiles of 12 strains suggested that these strains are associated with an acute form of Q fever.

Acute Disease↗