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At least 829 records · Page 46Linked to original sources
PubMed1995

Escherichia coli invasion of brain microvascular endothelial cells in vitro and in vivo: molecular cloning and characterization of invasion gene ibe10.

Most cases of neonatal Escherichia coli meningitis develop as a result of hematogenous spread, but it is not clear how circulating E. coli crosses the blood-brain barrier. In an attempt to identify E. coli structures contributing to invasion into the central nervous system (CNS), TnphoA mutagenesis was performed with an invasive CSF isolate of E. coli K1 strain RS218 (O18:K1:H7), and TnphoA mutants were examined for their noninvasive capability in brain microvascular endothelial cells (BMEC). The noninvasive mutants exhibited the invasive ability of < 1% of the parent strain. One of the noninvasive mutants (10A-23) with a single TnphoA insertion and no changes in phenotypic characteristics was found to be significantly less invasive into the CNS in the newborn rat model of hematogenous E. coli meningitis. The TnphoA inserts with flanking sequences were cloned and sequenced. A novel open reading frame (8.2 kDa) was identified. Open reading frame analysis indicated that the 8.2-kDa protein (Ibe10) contained multiple transmembrane domains. ibe10 was cloned into an expression vector, pQE30, and the purified Ibe10 was shown to inhibit invasion of BMEC by strain RS218. These findings indicate that ibe10 is one of the E. coli genes involved in the invasion of BMEC in vitro and in vivo.

Amino Acid Sequence↗
PubMed1996

Ability of Escherichia coli isolates that cause meningitis in newborns to invade epithelial and endothelial cells.

Escherichia coli isolates that cause meningitis in newborns are able to invade the circulation and subsequently cross the blood-brain barrier. One mechanism for traversing the blood-brain barrier might involve transcytosis through the endothelial cells. The ability of the meningitis isolate E. coli IHE3034, of serotype 018:K1:H7, to invade epithelial (T24) and endothelial (EA-hy926) cells was investigated by the standard gentamicin survival assay and by electron microscopy. Human bladder epithelial and endothelial cells were efficiently invaded by strain IHE3034, whereas epithelial human colon Caco-2 cells, canine kidney MDCK cells, and the opossum [correction of opposum] epithelial kidney cell line OK were not invaded. The ability to invade human epithelial cells of the bladder could also be demonstrated for several other newborn meningitis E. coli strains and one septicemic E. coli strain. Studies utilizing inhibitors which act on eukaryotic cells revealed a dependence on microfilaments as well as on microtubules in the process of E. coli IHE3034 entry into T24 and EA-hy926 cells. These results indicated that cell cytoskeletal rearrangements are involved in bacterial uptake and suggest that there are either two pathways (microtubule dependent and microfilament dependent) or one complex pathway involving both microtubules and microfilaments. The intracellular IHE3034 organisms were contained in a host-membrane-confined compartment mainly as single microorganisms. Intracellular replication of 1HE3034 was not detected, nor did the number of intracellular bacteria decrease significantly during a 48-h period. The ability of E. coli O18:K1 to invade and survive within certain eukaryotic cells may be another virulence factor of meningitis-associated E. coli.

Actin Cytoskeleton↗
PubMed1999

The gene locus yijP contributes to Escherichia coli K1 invasion of brain microvascular endothelial cells.

Most cases of Escherichia coli meningitis develop as a result of hematogenous spread, but it is not clear how circulating E. coli crosses the blood-brain barrier. A TnphoA mutant of E. coli K1 RS218 was shown to be significantly less invasive than its parent strain in bovine and human brain microvascular endothelial cells (BMEC), which constitute the blood-brain barrier. More importantly, traversal of the blood-brain barrier was significantly less with this mutant than with the parent strain in newborn rats with experimental hematogenous meningitis. A DNA segment containing the TnphoA insertion site was cloned from RS218, and the cloned DNA complemented the TnphoA mutant in invasion of BMEC. Nucleotide sequence revealed a near identity to that of a hypothetical yijP gene (also called f577) in the E. coli K-12 genome. Sequence analysis indicated that the E. coli K1 yijP gene likely encodes a 66. 6-kDa membrane protein. Deletion and complementation experiments indicated that the yijP gene was involved in E. coli K1 invasion of BMEC, i.e., the invasive ability of E. coli K1 was significantly reduced after yijP was deleted and was restored by complementation with a plasmid containing the yijP open reading frame. This is the first demonstration that the yijP gene locus plays a role in the pathogenesis of E. coli K1 meningitis.

Animals↗
PubMed1999

Equine influenza in the United Kingdom in 1998.

In 1998, equine influenza was diagnosed by serology and nucleoprotein enzyme-linked immunosorbent assay as the cause of acute respiratory disease in vaccinated and unvaccinated horses in the UK. The signs were generally milder in vaccinated horses and completely susceptible animals showed the most severe signs, including pyrexia, inappetence, coughing, mucopurulent nasal discharge and secondary bacterial pneumonia. In a detailed investigation of an outbreak among 52 vaccinated thoroughbreds in a flat racing yard, more than 60 per cent of the horses seroconverted on the evidence of paired serum samples tested by single radial haemolysis (SRH). Preliminary sequencing and characterisation of an isolate from this outbreak indicated that it was an 'American-like' strain. In addition, in this outbreak there was a larger proportion of horses with preinfection SRH titres greater than 140 mm2 that subsequently seroconverted than in other recent outbreaks from which 'European-like' strains have been isolated. This result suggested that the cross-protectivity between circulating 'American-like' strains and the 'European-like' strains of A/equine-2 viruses present in current vaccines may be decreasing.

Animals↗
PubMed1983

Propylthiouracil (PTU) pharmacology in the rat. I. Serum and thyroid PTU measurements by radioimmunoassay.

We have developed a highly sensitive and specific RIA for propylthiouracil (PTU) which uses 125I-labeled PTU as the radioactive ligand. At a final antibody dilution of 1:10,000, the detection limit for PTU was 100 pg; cross-reactivity with circulating, urinary, and intrathyroid PTU metabolites was negligible. Using this assay, serum and thyroid PTU levels were determined after short term (1 week) and long term (1 month) PTU treatment at doses of 0.0001-0.05%. Serum PTU was a linear function of the PTU dose (r = 0.99; P less than 0.001), whereas thyroid PTU was a linear function of the logarithm of the PTU dose (r = 0.99; P less than 0.001). Serum PTU levels were higher after 1 month of treatment than after administration for 1 week, probably because steady state conditions were not achieved after 1 week. At several doses, thyroid PTU levels were also higher after 1 month of treatment, but the differences were not as striking as those seen in the serum levels. The pharmacokinetic data are consistent with a multicompartmental model for PTU distribution. The logarithmic relationship between thyroid PTU and PTU dose suggests a saturable uptake mechanism for PTU by the thyroid; inhibition of thyroid PTU uptake by PTU itself could also explain these observations.

Animals↗
PubMed1987

Common carotid occlusion for unclippable carotid aneurysms: an old but still effective operation.

We present a selected series of nine patients with unclippable internal carotid artery aneurysms to illustrate our current approach to this problem. Eight of the nine underwent common carotid ligation after preoperative angiographic evaluation. Tolerance to carotid occlusion was determined intraoperatively by awake examination, electroencephalogram (EEG) monitoring, and carotid stump pressure measurements. No patient developed a permanent deficit; seven of eight treated aneurysms have thrombosed. Our experience and review of the literature indicate that most ischemic complications after carotid ligation seem to be thromboembolic, rather than due to "low flow" from poor collateral circulation. For this reason, we have gradually come to favor common carotid (CCA) over internal carotid (ICA) occlusion in many of these patients. After CCA occlusion, the ICA frequently remains open and embolic complications are therefore less likely. An extracranial-intracranial bypass procedure is performed only in those patients with poor collateral circulation demonstrated by cross compression angiographic studies, by the development of new deficits during test occlusion, or by the appearance of EEG changes during test occlusion. We suggest that CCA ligation remains a useful alternative in the management of unclippable internal carotid aneurysms.

Adult↗
PubMed1978

Double inferior vena cava or iliac vein occlusion? A diagnostic problem in radionuclide venograms.

Radionuclide venography in two patients with suspected deep venous disease revealed double channel drainage with cross-pelvic collateral circulation. Contrast inferior venacavograms revealed that one patient had persistent right and left supracardinal veins (double inferior vena cava) and the other had iliac vein occlusion with ascending lumbar collateral circulation. The similarity of radionuclide venographic findings in these two patients emphasizes the importance of contrast venacavography in patients with this appearance on radionuclide venography.

Adult↗
PubMedDate not supplied

African tick-bite fever: four cases among Swiss travelers returning from South Africa.

BACKGROUND: African tick-bite fever (ATBF) is a recently described disease belonging to the spotted fever group. It is caused by Rickettsia africae, and cases are mainly diagnosed in travelers returning from sub-Saharan Africa. METHODS: We report four cases of ATBF among Swiss travelers returning from a 1-month trip in rural South Africa. Diagnosis was made on the basis of clinical, epidemiologic and serologic findings that we describe in detail. Serology was performed using microimmunofluorescence (MIF) assay 2 weeks, 6 weeks and 14 months after the commencement of symptoms. RESULTS: All patients developed the typical eschar and a rash; two had a local lymphadenopathy and one a lymphangitic reaction. Two patients developed transient neuropsychiatric symptoms such as headache, irritability and depressed mood. All four patients had rises in both IgM and IgG classes of anti-R. africae antibodies. After 1 year, only two patients still had measurable circulating antibodies. Cross-reactions with R. conorii were noted. Three patients were cured after a short course of doxycycline; one required 15 days of treatment. CONCLUSIONS: ATBF is a benign disease increasingly being diagnosed in travelers. After ruling out malaria, ATBF diagnosis relies upon a detailed travel history and the classical findings of influenza-like symptoms, fever, one or more necrotic eschars, and rash. Serologic tests usually help to confirm the diagnosis. Neuropsychiatric symptoms specifically associated with ATBF are reported here for the first time.

Adolescent↗
PubMed2000

[Mechanisms for tissue transport of fatty acids].

Fatty acids (FA) play an important role in energy metabolism. They are not only used as substrates for energy production but are also involved in many other metabolic pathways. However, the exact mechanisms by which FA are taken up by the cells are not yet fully understood. Fatty acids circulating in blood cross the cell membranes partly via a mechanism facilitated by plasma membrane proteins and partly via a passive diffusion mechanism, the former mechanism being of major importance.

Animals↗
PubMed2002

Patients with unstable angina pectoris present increased humoral response against Helicobacter pylori in comparison with patients with aggravated dyspepsia.

A role of autoimmune process and its link with bacterial infections in initiation or aggravation of atherosclerosis symptoms has been suggested. Antigenic mimicry and cross-reactivity of circulating antibodies have been indicated as some major factors in this process. In this study, the prevalence and titers of IgG and IgA antibodies reacting with glycine extract of H. pylori surface antigens were determined immunoenzymatically (ELISA) in the group of patients with unstable ischaemic heart disease and in patients with aggravated dyspepsia. Our results reveal that elevated titers of IgG anti-H. pylori are more typical for cardiac patients and lower prevalence of IgA anti-H. pylori--for those with aggravated dyspepsia. This supports the hypothesis that intensed humoral response in immunoglobulins class G against some bacterial antigens may play a role in the aggravation of symptoms of coronary atherosclerosis.

Adult↗
PubMed2005

Metabolic effects of IGF-I deficiency: lessons from mouse models.

Insulin and insulin-like growth factors (IGFs) belong to the most biologically characterized family of peptides involved in metabolism, growth and development. The cellular responses to the IGFs are mediated primarily by the IGF-I receptor. The IGF-I receptor is a member of the family of tyrosine kinase growth factor receptors, and is highly homologous (70%) to the insulin receptor, especially in the tyrosine kinase domain (84%) ADDIN. Upon ligand binding to the extracellular region, the intrinsic tyrosine kinase domain of the receptor is activated. In the past it was believed that insulin activates primarily metabolic processes while IGFs promote cell growth and differentiation. However, in the last two decades many animal models of IGFI deficiency and excess revealed the importance of IGF-I in carbohydrate and lipid metabolism and now it is clear that these peptide hormones together with growth hormone (GH) work in a coordinate and interdependent manner. In the circulation, IGFs are bound in a binary complex with a family of high affinity IGF-binding proteins (IGFBPs) ADDIN. However, most of the circulating IGF-I associates with a high molecular weight complex approximately 150 KDa consisting of IGFBP-3 and the acid labile subunit (ALS) ADDIN. Once the ternary complex dissociates, the binary complexes of IGFBP-IGFs are removed from the circulation and by crossing the endothelium to reach the target tissues and to interact with cell surface receptors. In the present review we will summarize the role of GH and IGF in somatic growth and focus on the metabolic effects of IGF-I deficiency as assessed in various mouse models.

Animals↗
PubMed1991

[The role of precipitating serum antibodies in tuberculosis patients].

The content of serum alpha 1-proteinase inhibitors (alpha 1-PI), alpha 2-macroglobulins, transferrins, albumin, immunoglobulins A, M and G and C3- and C4-complement factors was investigated in a group of patients (n = 35) with pulmonary tuberculosis who showed precipitating antituberculous circulating antibodies having the properties of autoantibodies. A direct relationship between the available circulating antibodies cross-reacting with the tissues and the rate of an extrapulmonary localization of tuberculous process in pulmonary tuberculosis patients, on the one hand, and their inverse relationship to the level of blood alpha 1-PI, on the other, were revealed. It is recommended to define cross-reacting antibodies and alpha 1-PI concentration to predict the risk of extrapulmonary foci of a tuberculous inflammation.

Antibodies, Bacterial↗
PubMed1987

Enzyme-linked immunosorbent assay and radioimmunoassay of serum pepsinogen A.

The determination of serum pepsinogen A (= pepsinogen I) levels is of clinical importance in the study of duodenal ulcer, atrophic gastritis and gastric cancer. In the present study two different quantitative immunological techniques for serum pepsinogen A were compared: a radioimmunoassay (RIA) (Helsinki) and an enzyme-linked immunosorbent assay (ELISA) (Amsterdam). Serum samples of 177 subjects with various gastric diseases were tested in a double blind study. The correlation was excellent (r = 0.954 in the range 0-760 micrograms/l and r = 0.971 in the range 0-100 micrograms/l). The functional relationship between ELISA (x) and RIA (y), determined by weighted model II regression, was y = 1.12x-0.54. Initially the use of goat anti-PGA in the ELISA resulted in falsely high values in about 10% of the individuals. This was caused by circulating antibodies cross-reacting with goat IgG. This artefact was eliminated by pre-incubation of all samples with non-immune goat serum.

Clinical Trials as Topic↗
PubMed1980

[Hapten inhibition: inhibition of antibody dependent dextran side effects by means of low molecular dextran (dextran 1) as a monovalent hapten].

Dextran-induced anaphylactoid reactions can be attributed to preformed circulating antibodies cross-reacting with dextrans. Therefore, after intravenous administration of clinical dextran, formation of immune complexes with resulting complement activation and secondary formation and/or release of mediators with clinical symptoms of an immune complex or aggregate anaphylaxis can occur (type-III immune reaction). Antigen antibody reactions can be prevented if the antigen-binding sites of the antibodies are specifically blocked by monovalent haptens (low molecular non-immunogenic antigens). The effectiveness of this principle of 'hapten inhibition' could be proven in vitro as well as in animal experiments. In volunteer studies intravenous administration of the low molecular dextran in a 15% solution (Dextran 1), with a molecular weight around 1,000 functioning as monovalent hapten, was well tolerated.

Anaphylaxis↗
PubMed1980

Fetal perfusion with maternal blood; a possible sequel to fetal catheterization in the pig.

Plasma gamma-globulin concentrations were increased in three catheterized pig fetuses in which the packed red cell volume rose rapidly after surgery, but were not increased in one fetus in which the packed cell volume remained normal. The increases in packed cell volume and gamma-globulin concentration were closely correlated. The source of the gamma-globulin was investigated in one sow with catheterized fetuses. Maternal proteins, identified by [125I]-labelling and gel diffusion, crossed to the circulation of the one catheterized fetus with an elevated packed cell volume but not to the other, in which packed cell volume remained normal, nor to two unoperated fetuses. The results suggest that vascular anastmosis between fetal and maternal circulations is a possible sequel to cannulation in this species.

Animals↗
PubMed1994

Perioperative infusion of nifedipine and metoprolol provides antiischemic and antiarrhythmic protection in patients undergoing elective aortocoronary by-pass surgery.

A randomised study was performed on 70 patients undergoing elective coronary by-pass procedure to examine whether the combined, perioperative, 24-hour infusion of nifedipine and metoprolol reduces the incidence of perioperative myocardial ischemia and arrhythmias. The control group received nifedipine only. Repeated assessments of serum enzyme levels and 12-lead-ECG together with a 3-channel Holter monitoring over 48h were used to classify perioperative myocardial ischemia and supraventricular and ventricular arrhythmias. The two groups did not differ with respect to their demographic data, extracorporeal circulation, aortic cross-clamping time, or number of distal anastomosis. No perioperative myocardial infarction in either group was detected. However, a significantly lower incidence of transient ischemic event was observed in the NM group as compared transient ischemic events was observed in the NM group as compared to the N group. In addition, there was a tendency towards lower CK-MB-level and peak-values of CK- and CK-MB-enzymes in the NM group. With regard to perioperative dysrhythmias, there was a significantly lower incidence of sinus tachycardia and atrial flutter/fibrillation in the NM group as compared to the N group. In addition, postoperative heart rate was lower in the NM group starting from the 6th hour after opening the aortic cross-clamp. In conclusion, the combined perioperative infusion of nifedipine and metoprolol is superior in preventing perioperative myocardial ischemia and decreasing the incidence of supraventricular arrhythmias as compared to a single-drug regimen with nifedipine.

Arrhythmias, Cardiac↗
PubMed1994

[Myocardial revascularization in aged patients: what is the surgical risk?].

There are still controversies about the surgical results of myocardial revascularization in aged population, in terms of cardiac and non-cardiac morbidity and mortality. This issue prompted us to study retrospectively 71 patients older than 75 years electively operated of coronary artery bypass grafting (CABG) from June 1990 to June 1993 (Group A). Elderly population was compared with a contemporaneous and concurrent control group of patients younger than 75 years (Group B). Patients > 75 years have been divided in successive subgroups according to the severity of coronary artery disease (3 vessel disease 67.7%, 2 vessel disease 26.7%, 1 vessel disease 5.6%), echocardiographic ejection fraction (EF > 50%: 40.8%; 50-30%: 42.2%; < 30%: 16.9%) and preoperative risk factors. Left internal thoracic artery (LITA) utilization rate was 97.1% in Group B and 57.7% in Group A (p < 0.001). Cardiopulmonary bypass circulation, aortic cross-clamping time and number of coronary anastomoses were similar in the 2 groups (2.87 +/- 0.9 versus 2.8 +/- 0.8, NS). Operative mortality rate of aged population was 4.2% while no patient of Group B died (NS). Concerning the cardiac morbidity, there were no significantly differences between the 2 groups: myocardial infarction occurred in 3 patients of Group B (4.2%) and in 5 patients of Group A (7%; NS). Atrioventricular block was also similar in the 2 groups. Non-cardiac complications occurred more frequently in the aged population group: neurologic complications in 11.2% versus 1.4% (p < 0.04), renal insufficiency in 12.6% versus 1.4% (p < 0.03) and respiratory failure in 9.8% versus 1.4% (p = 0.06). (ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗