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At least 433 records · Page 24Linked to original sources
PubMed2004

To isolate or not to isolate? Analysis of data from the German Nosocomial Infection Surveillance System regarding the placement of patients with methicillin-resistant Staphylococcus aureus in private rooms in intensive care units.

OBJECTIVE: To investigate whether isolating patients with MRSA in private rooms in ICUs (or cohorting) is a protective factor for nosocomial MRSA infection. DESIGN: Association between nosocomial MRSA infection rates and ICU structure and process parameters in the German Nosocomial Infection Surveillance System (KISS). SETTING: Two hundred twelve ICUs participating in KISS in 2001. METHODS: In June 2001, a structured questionnaire was sent to the participating ICUs regarding their preventive measures, their type and size, their patient-to-personnel ratios, and routine cultures. Univariate and multivariate analyses were conducted to identify risk factors for nosocomial MRSA infection. RESULTS: The questionnaire was completed by 164 (77.4%) of the ICUs. These ICUs had 325 nosocomial MRSA infections in a 5-year period (1997 to 2001). The mean incidence density of nosocomial MRSA infections was 0.3/1,000 patient-days. Ninety-one ICUs (55.5%) did not register any nosocomial MRSA infections during the observation period. Forty-two ICUs had an incidence density of at least 0.3/1,000 patient-days (75th percentile). Surgical ICUs were found to be a risk factor for a nosocomial MRSA infection rate above this threshold. Multivariate analysis found surgical ICUs to be an independent predictor and isolation in private rooms (or cohorts) to be a protective factor (OR, 0.36; CI95, 0.17-0.79). CONCLUSION: Many (34.4%) of the German ICUs have not isolated MRSA patients in private rooms or cohorts, a procedure associated with lower MRSA infection rates in this study.

Cross Infection↗
PubMed1986

Effects of d,1-propranolol and haloperidol on aggressive behavior induced in mice by isolation and isolation plus amphetamine treatment.

We measured the aggressive behavior of isolated mice treated or not with d,1-amphetamine (6.0 mg/kg, ip) and injected with different doses of d,1-propranolol (10.0, 20.0 or 30.0 mg/kg, ip) or haloperidol (0.5 or 1.0 mg/kg). d,1-Amphetamine (6.0 mg/kg, ip) decreased the aggressiveness of the isolated mice and induced stereotyped behavior. Haloperidol antagonized amphetamine-induced stereotypy, increased the latency to the 1st attack and decreased duration of fighting and frequency of attacks in mice treated or not with amphetamine. d,1-Propranolol did not change stereotypy but decreased aggressiveness in a dose-dependent way, being more effective against aggression induced by isolation per se. These results are discussed in terms of the interference of the drugs with the activity of either catecholaminergic neurons or midbrain reticular formation. The latter effect seems to be the most likely explanation for the observed anti-aggressive effects of haloperidol and d-1, propranolol.

Aggression↗
PubMed2000

Ursolic acid isolated from Eucalyptus tereticornis protects against ethanol toxicity in isolated rat hepatocytes.

Ursolic acid is the active material isolated from the leaves of the Eucalyptus hybrid E. tereticornis. In the present study, it has shown a significant preventive effect in vitro against ethanol-induced toxicity in isolated rat hepatocytes. Compared with the incubation of isolated hepatocytes with ethanol only, the simultaneous presence of ursolic acid in the cell suspension preserved the viability of hepatocytes and reversed the ethanol-induced loss in the level of all the marker enzymes (AST, ALT and AP) studied. Ethanol alone resulted in a 48%-54% decrease in the viability and a 42%-54% reduction in the biochemical parameters of the hepatocytes. Ursolic acid showed a concentration dependent (1-100 microg/mL) preventive effect (12%-76%) on alcohol-induced hepatocyte toxicity by restoring the altered parameters. The results thus suggest the effective use of an in vitro test system as an alternative for in vivo assessment of hepatoprotective activity of purified material.

Alanine Transaminase↗
PubMed1993

Complete nucleotide sequence of HTLV-II isolate NRA: comparison of envelope sequence variation of HTLV-II isolates from U.S. blood donors and U.S. and Italian i.v. drug users.

The entire nucleotide sequence of human T-cell lymphotropic virus type II (HTLV-II) from a previously described isolate of patient NRA (HTLV-IINRA) was determined. Clones encoding the 5' LTR and gag, pol, env and tax/rex open reading frames were subcloned and sequenced on both strands. The provirus consisted of 8957 nucleotides and showed 95.2% homology with the HTLV-IIMo prototype at the nucleotide level. Less than 5% amino acid variation between HTLV-IINRA and HTLV-IIMo was observed for coding regions. Although isolate HTLV-IINRA had an additional 25 amino acids at the 3' end of tax/rex, this region was 96% homologous with the 5' end of HTLV-IIMo 3' LTR. To further investigate HTLV-II variability, a portion of the env gp46 gene derived from 9 HTLV-II infected persons was amplified by polymerase chain reaction and sequenced. Sequence was obtained for 320 nucleotides corresponding to HTLV-IIMo positions 5291 to 5610. Isolates similar to the HTLV-IIMo and HTLV-IINRA prototypes were identified, and sequences were highly conserved.

Amino Acid Sequence↗
PubMed2000

Genetic diversity of hantaviruses isolated in china and characterization of novel hantaviruses isolated from Niviventer confucianus and Rattus rattus.

The antigenic and genetic properties of 46 hantaviruses from China, 13 from patients, 23 from rodents, and 10 from unknown hosts, were compared with those of other hantaviruses. The viruses were classified as either Hantaan (HTN) or Seoul (SEO) viruses. A phylogenetic analysis of the partial M (300 bp) and S (around 485 bp) genomes of HTN viruses identified nine distinct genetic subtypes, one consisting of isolates from Korea. The SEO viruses were divided into five genetic subtypes, although they had less variability than the HTN subtypes. There was a correlation between the subtype and province of origin for four subtypes of HTN viruses, confirming geographical clustering. Hantaan virus NC167 isolated from Niviventer confucianus and SEO virus Gou3 isolated from Rattus rattus were the basal clades in each virus. The phylogenetic trees constructed from the entire S and M segments suggested that NC167 was introduced to N. confucianus in a host-switching event. The reactivity of a panel of 35 monoclonal antibodies was almost exactly the same in NC167 and a representative HTN virus and in Gou3 and a representative SEO virus. However, there was a one-way cross-neutralization between them. These results confirm the varied nature of Murinae-associated hantaviruses in China.

Animals↗
PubMed1995

Isolation and experimental oral transmission in pigs of a porcine reproductive and respiratory syndrome virus isolate.

A virus inducing a cytopathic effect on porcine alveolar macrophages was isolated from the lungs of a pig with respiratory problems and lesions of proliferative and necrotizing pneumonia. The isolate was found to react with porcine reproductive and respiratory syndrome virus (PRRSV) monoclonal antibodies by indirect immunofluorescence and was designated LHVA-93-3. The virus could also be propagated on the MARC-145 cell line. The LHVA-93-3 macrophage-passaged isolate was inoculated orally or intranasally in four-week-old specific pathogen-free pigs. Histologically, focal to multifocal lesions of proliferative, necrotizing and interstitial pneumonia could be observed in the lungs of pigs inoculated orally or intranasally, 6 and 10 days post-inoculation. Virus could be reisolated from essentially the same tissues including serum following both routes of infection. The distribution of PRRSV antigens in fixed tissues as determined by immunogold silver staining (IGSS) was similar in orally or intranasally inoculated pigs. The results of this experimental transmission study indicate that pigs may become infected by PRRSV following oral as well as intranasal exposure.

Animals↗
PubMed1981

A method for the purification of single A, B and D cells and for the isolation of coupled cells from isolated rat islets.

A method has been developed for the purification of single A, B and D cells and for the isolation of coupled islet cells. Isolated rat islets were dissociated by repeated pipetting in the presence of trypsin and ethylene glycol bis (beta-aminoethyl ether) N,N' tetra-acetic acid (EGTA), and then filtered through nylon and Percoll; the cell preparation consisted of 70% single and 30% coupled cells. Sizing of the cells led to the recognition of a small-islet cell population (35%; cell volume 200-600 micrometer 3) composed of A and D cells, and a large-islet cell population (65%; cell volume 600-1500 micrometer 3) identified as B cells. Differences in sedimentation velocity formed the basis for the islet cell separation by counterflow elutriation. Single islet cells eluted prior to coupled cells and were distributed over A and D cell-enriched fractions I and II (65% A, 25% B, 10% D) and the B cell-enriched fraction III (93% B). The slightly different densities of A (d = 1.068), B (d = 1.065) and D (d = 1.070) cells allowed a subsequent purification by density gradient centrifugation resulting in a final 10- to 30-fold enrichment in either A, B or D cells. Most coupled islet cells were recovered in fraction IV, occurred mainly as doublets and were composed of 90% B cells and 7% D cells; the multiple pseudopods, which characterize isolated D cells, might contribute to the coupling tendency of the D cells. It is concluded that the purified A, B and D cell fractions and the coupled islet cell preparations offer a direct approach to the study of individual islet cell types and their intercellular communication.

Animals↗
PubMed1991

Exchange of chromosomal markers by natural transformation between the soil isolate, Pseudomonas stutzeri JM300, and the marine isolate, Pseudomonas stutzeri strain ZoBell.

Both the soil isolate, Pseudomonas stutzeri JM300, and the marine isolate, Pseudomonas stutzeri strain ZoBell, have been shown previously to be naturally transformable. This study reports the detection of genetic exchange by natural transformation between these two isolates. Transformation frequency was determined by filter transformation procedures. Three independent antibiotic resistance loci were used as chromosomal markers to monitor this exchange event: resistance to rifampicin, streptomycin, and nalidixic acid. The maximum frequencies of transformation were on the order of 3.1 to 3.8 x 10(-6) transformants per recipient; frequencies over an order of magnitude greater than those for spontaneous antibiotic resistance, although they are lower than those observed for soil:soil or marine:marine strain crosses. This exchange was inhibited by DNase I. Transformation was observed between soil and marine strains, both by filter transformation using purified DNA solutions and when transforming DNA was added in the form of viable donor cells. The results from this study support the close genetic relationship between P. stutzeri JM300 and P. stutzeri strain ZoBell. These results also further validate the utility of P. stutzeri as a benchmark organism for modeling gene transfer by natural transformation in both soil and marine habitats.

Deoxyribonuclease I↗
PubMed1991

The infection characteristics of a South African isolate of Schistosoma mansoni: a comparison with a Puerto Rican isolate in BALB/c mice and Mastomys coucha.

The infection characteristics of a South African (RSA) laboratory isolate of Schistosoma mansoni were compared with those of a widely studied Puerto Rican (PR) isolate in BALB/c mice and Mastomys coucha over the period of 5-12 weeks after infection. The infectivity, maturation and, in particular, the fecundity of the two schistosomes were found to differ markedly. Tissue egg-accumulation rates of the RSA strain were substantially lower than those of the PR strain. Although the maturation of both parasite strains was somewhat delayed in M. coucha, the characteristics of each was essentially consistent in both rodent hosts. Notwithstanding the possible influence of prolonged laboratory passage on the behaviour of schistosome isolates, the results of the present study are nevertheless considered to support the idea that parasite strain differences may, to some extent, account for regional variations in the morbidity of intestinal schistosomiasis. The need to be cognizant of the characteristics of individual host-parasite combinations when comparing different schistosome species and strains, particularly with respect to both their abilities to elicit immunopathology and induce concomitant immunity and their susceptibilities to chemotherapy, is highlighted.

Animals↗
PubMed1989

Preliminary comparisons of the biological properties of two strains of feline immunodeficiency virus (FIV) isolated in Japan with FIV Petaluma strain isolated in the United States.

Two strains of feline immunodeficiency virus (FIV) were isolated directly from peripheral blood mononuclear cells (PBMCs) of Japanese domestic cats or indirectly from PBMCs of specific pathogen free (SPF) cats inoculated with whole blood from naturally infected cats with FIV by cocultivation with primary PBMCs from SPF cats. Two isolates, designated as FIV TM 1 and FIV TM 2, had a lentivirus-like morphology by electron microscopy, a tropism for interleukin-2 dependent T-lymphocytes and Mg2+-dependent reverse transcriptase activity. By immunoblotting the isolates gave bands at 130, 48, 44, 40, 28, 17, and 13 kDa, and these bands except 130 kDa were detected in FIV Petaluma strain when reacted with the plasma of cats infected naturally with FIV TM 1 strain.

Animals↗
PubMed1975

Letters to the editor: On the transfer of nuclear RNA into isolated mitochondria. Further evidence for template properties of nuclear RNA taken up by isolated mitochondria.

Some properties of nuclear RNA taken up by isolated mitochondria during aerobic incubation were studied. Nuclear RNA fraction re-isolated from incubated mitochondria was characterized by homogeneous sedimentation distribution in sucrose gradient (7-9S) and by absence of extended secondary structure. In this respect the RNA fraction differed from the nuclear RNA added to mitochondria and was similar to in vivo rapidly labelled mitochondrial RNA. The hybridization pattern of re-isolated RNA with nuclear DNA is consistent with the presence of transcripts from unique DNA sequences in this RNA fraction.

Aerobiosis↗
PubMed1984

Comparison of cytologic and biochemical properties between liver cells isolated from adult rats by trypsin perfusion and those isolated by collagenase perfusion.

Primary cultures of liver cells isolated from adult rats by trypsin and collagenase perfusion techniques were carried out to compare cytologic and biochemical properties between the differently prepared cells. Trypsin-dispersed cells consisted of comparatively smaller cells, whereas collagenase-dispersed cells consisted of larger cells. The cell attachment efficiency on culture day 1 was about twice as high in the liver cells prepared with collagenase than those prepared with trypsin. Mature hepatocytes isolated by collagenase perfusion could be maintained in the primary culture for a longer period than those isolated by trypsin perfusion. Epithelial-like clear cells started to grow much earlier in the primary culture of the trypsin-dispersed liver cells than in that of the collagenase-dispersed liver cells. Earlier proliferation of epithelial-like clear cells could not be induced by in vitro trypsinization of the collagenase-dispersed liver cells. Both kinds of enzymatically prepared liver cells showed albumin production and exhibited glucose 6-phosphatase (D-glucose-6-phosphate phosphohydrolase, EC 3.1.3.9, G6Pase) and tyrosine aminotransferase (L-tyrosine: 2-oxoglutarate amino-transferase, EC 2.6.1.5, TAT) activities for 1 week in the primary culture. Albumin production was higher in the liver cells prepared with collagenase than those prepared with trypsin, whereas G6Pase activity was almost the same between them. TAT activity up to culture day 2 was about 3-fold higher in the liver cells prepared with collagenase than in those prepared with trypsin. Combined supplementation of dexamethasone (1 X 10(-5)M) and insulin (10 micrograms/ml) consistently improved the cell attachment efficiency and was very effective in the maintenance of mature hepatocytes in both types. Furthermore, these hormones enhanced the albumin production and TAT activity in both types.

Albumins↗
PubMed2000

Liposomes as fatty acids carriers in isolated rat liver: effect on energy metabolism and on isolated mitochondria activity.

The effects of fatty acids (FA)-carrier, egg-lecithin liposomes (LIPO) as alternative to BSA, on ATP, glycogen and glucose contents in isolated perfused liver of fed rats were non-invasively studied using 31P/13C nuclear magnetic resonance (NMR). Oxidative phosphorylation was studied in isolated mitochondria from the same liver consecutively to the NMR experiments. ATP content decreased slowly and ATP turnover was similar during the perfusion with saline solution (KHB) or LIPO. However, LIPO induced an enhancement of respiratory control ratio in isolated mitochondria. Tissue glycogen and glucose content decreased when FA (linoleate or linolenate) were perfused with defatted BSA (3%) or LIPO (600 mg/l) whereas glucose excretion level was unchanged and lactate excretion tended to increase, reflecting changes in the cytosolic redox state and/or an enhancement of glycolysis. Addition of FA (0.5 or 1.5 mM) to LIPO caused a dramatic fall in liver ATP, a mitochondrial uncoupling and an impairment of the phosphorylation activity. Perfusion with FA (1.5 mM) carried by BSA significantly increased the ATP degradation without change of mitochondrial function. Owing to the higher affinity of BSA than LIPO for FA, these latter could be more easily released from complex LIPO-FA, increasing their uncoupling effect. Hence, the FA concentrations have to be largely decreased from the above currently used concentrations to avoid this effect. It will then be possible to minimize the effector action of FA and to study their more specific metabolic function as fuel. It was concluded that LIPO were appropriate carriers to study the different metabolic effects of FA.

Adenosine Triphosphate↗
PubMed2000

Isolation and characterization of two new methanesulfonic acid-degrading bacterial isolates from a Portuguese soil sample.

Two novel bacterial strains that can utilize methanesulfonic acid as a source of carbon and energy were isolated from a soil sample collected in northern Portugal. Morphological, physiological, biochemical and molecular biological characterization of the two isolates indicate that strain P1 is a pink-pigmented facultative methylotroph belonging to the genus Methylobacterium, while strain P2 is a restricted methylotroph belonging to the genus Hyphomicrobium. Both strains are strictly aerobic, degrade methanesulfonate, and release small quantities of sulfite into the medium. Growth on methanesulfonate induces a specific polypeptide profile in each strain. This, together with the positive hybridization to a DNA probe that carries the msm genes of Methylosulfonomonas methylovora strain M2, strongly endorses the contention that a methanesulfonic acid monooxygenase related to that found in the previously known methanesulfonate-utilizing bacteria is present in strains P1 and P2. The isolation of bacteria containing conserved msm genes from diverse environments and geographical locations supports the hypothesis that a common enzyme may be globally responsible for the oxidation of methanesulfonate by natural methylotrophic communities.

Alphaproteobacteria↗
PubMed2004

A comparison of homologous genes encoding aminopeptidases among bird and human Encephalitozoon hellem isolates and a rabbit E. cuniculi isolate.

Encephalitozoon cuniculi and E. hellem are often recognized as the agents of human microsporidiosis, but less than optimal therapy is available for treatment. The identification of enzymes critical to the parasitic life cycle is an important step in finding targets for potential drug development. Aminopeptidase gene sequences were obtained from cDNA and gDNA from avian and human E. hellem isolates and from a rabbit E. cuniculi isolate. At the amino acid level, the aminopeptidase sequences from the E. hellem human and bird isolates share >99% identity and are nearly 70% identical with the E. cuniculi sequence. Conserved HEXXH and GAMEN motifs classify the predicted aminopeptidase in the MA clan of the M1 family. The obtained aminopeptidase gene sequences are likely homologous to the previously reported E. cuniculi glutamyl aminopeptidase. The conservation of this aminopeptidase between species and divergence from mammalian aminopeptidases indicate that this enzyme may be a valid target for drug therapy.

Amino Acid Motifs↗
PubMed2006

Whole genome characterization of Potato virus Y isolates collected in the western USA and their comparison to isolates from Europe and Canada.

Potato virus Y (PVY) is a serious potato pathogen that affects potato seed and commercial production crops. In recent decades, novel PVY strains have been described that cause necrotic symptoms on tobacco foliage and/or potato tubers. The major PVY strains that affect potato include PVY(O) and PVY(N), which have distinct serotypes that can be differentiated by immunoassay. Other economically important strain variants are derived from recombination events, including variants that cause tuber necrotic symptoms (PVY(NTN)) and PVY(O) serotypes that cause tobacco veinal necrosis (PVY(N)-W, PVY(N:O)). Although the PVY(NTN) and PVY(N)-W variants were first reported in Europe, apparently similar strains have been appearing in North America. Confirmation of the existence of these recombinant strains in North America is important, as is whether they spread from a common source or were derived by independent recombination. Whole genome sequencing can be used to positively identify strain variants and begin to address the issue of origins. Symptomology, serology, RT-PCR, and partial sequencing of the coat protein region were used to identify isolates of the PVY(NTN), PVY(N), PVY(NA-N), and PVY(N:O) for whole-genome sequencing. Sequencing confirmed the presence of PVY(NTN) and PVY(N) isolates that were >99% identical to European sequences deposited in GenBank in the 1990's. Sequences of the PVY(NA-N) and PVY(N:O) types were 99.0% and 99.5% identical to known sequences, respectively. There was no indication that recombinant strains PVY(NTN) or PVY(N:O) had different parental origins than recombinant strains previously sequenced. This is the first confirmation by whole-genome sequencing that "European"-type strain variants of PVY(N) and PVY(NTN) are present in North America, and the first reported full-length sequence of a tuber necrotic isolate of PVY(N:O).

Canada↗
PubMed2003

Phylogenetic analysis of different isolates of Sulfobacillus spp. isolated from uranium-rich environments and recovery of genes using integron-specific primers.

The isolation and phylogenetic characterization of acidophilic moderate thermophilic bacteria from different locations of uranium mines and a uranium processing mill in Pakistan is reported. The dominant culturable bacteria found were related to Sulfobacillus thermosulfidooxidans in all the samples analyzed. Different strains displayed different levels of identity (95-97%) to 16S rDNA of known strains of this species, indicating group heterogeneity. Genomic DNA from five isolates was subjected to amplification using integron-specific primers HS286 and HS287. Recovery of different integron-linked genes from one of the isolates indicated the usefulness of this approach for gene mining in place of traditional gene recovery methodologies.

Bacillus↗
PubMed2005

Isolation of virus from a SARS patient and genome-wide analysis of genetic mutations related to pathogenesis and epidemiology from 47 SARS-CoV isolates.

Severe acute respiratory syndrome (SARS) caused by SARS-associated coronavirus (SARS-CoV) is a fatal disease. Prevention of future outbreaks is essential and requires understanding pathogenesis and evolution of the virus. We have isolated a SARS-CoV in China and analyzed 47 SARS-CoV genomes with the aims to reveal the evolution trends of the virus and provide insights into understanding pathogenesis and SARS epidemic. Specimen from a SARS patient was inoculated into cell culture. The presence of SARS-CoV was determined by RT-PCR and confirmed by electron microscopy. Virus was isolated followed by the determination of its genome sequences, which were then analyzed by comparing with other 46 SARS-CoV genomes. Genetic mutations with potential implications to pathogenesis and the epidemic were characterized. This viral genome consists of 29,728 nucleotides with overall organization in agreement with that of published isolates. A total of 348 positions were mutated on 47 viral genomes. Among them 22 had mutations in more than three genomes. Hot spots of nucleotide variations and unique trends of mutations were identified on the viral genomes. Mutation rates were different from gene to gene and were correlated well with periodical or geographic characteristics of the epidemic.

Adolescent↗