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Biomedical subjects

N Henry

Publications and source records attributed to N Henry.

At least 19 recordsLinked to original sources
PubMed2000

Effect of delayed infection control measures on a hospital outbreak of methicillin-resistant Staphylococcus aureus.

All patients positive for methicillin-resistant Staphylococcus aureus (MRSA) at the University Hospitals of Geneva, Switzerland, between 1989 and 1997 (N = 1771) were included in a cohort study to evaluate the consequences of delayed containment of a hospital-wide outbreak occurring during a 4-year absence of MRSA control measures. The effects of efforts to control both the MRSA reservoir and the number of bacteraemic patients were assessed. Intensive infection control measures were initiated in 1993 and included patient screening, on-site surveillance, contact isolation, a computerized alert system, and hospital-wide promotion of hand hygiene. An increase in the rate of new MRSA-infected or -colonized patients was observed between 1989 and 1994 (from 0.05 to 0.60 cases per 100 admissions), which subsequently decreased to 0.24 cases in 1997 (P<0.001). However, the proportion of laboratory-documented methicillin-resistant isolates among all S. aureus showed little variation in the years from 1993 onwards (range, 19-24%), reflecting the result of an increase in the number of screening cultures. The annual number of patients with MRSA bacteraemia strongly correlated with the hospital-wide prevalence of MRSA patients (R(2)= 0.60; P = 0.01) and the rate of new MRSA patients (R(2)= 0.97; P<0.001). Consequently, the attack rate of nosocomial MRSA bacteraemia served as an excellent marker for the MRSA patient reservoir. In conclusion, despite delayed implementation, infection control measures had a substantial impact on both the reservoir of MRSA patients and the attack rate of MRSA bacteraemia.

Cohort Studies↗
PubMed1998

[Prevalence of nosocomial infections in a university hospital: distribution, predisposing factors and diagnostic indices].

Nosocomial infections are a major challenge for modern medicine and contribute to increased resource use in health care systems. The first hospital-wide prevalence survey of nosocomial infections was conducted at the University of Geneva Hospitals in 1994. At the time of the study, 16.9% of admitted patients had nosocomial infections (168/994). Leading infection sites were: urinary tract (30%), respiratory tract (17%), surgical wounds (12%) and bloodstream (9.6%). Rates of infection varied between hospital wards: intensive care (21%), surgery (19%), rehabilitation (18%), internal medicine (13%). However, the distribution of nosocomial infections varied according to surveillance and attribution rules. Optimal detection of nosocomial infections requires ward surveillance, including revision of microbiology, nursing (Kardex) and medical records; the combination of fever above 38 degrees C, prescription of antimicrobial agent(s), and positive microbiological records suggested the diagnosis of nosocomial infections in 95% of situations. Priorities for infection control were derived from these results.

Adolescent↗
PubMed1997

Comparison of agar dilution, broth dilution, disk diffusion, and the E-test for susceptibility testing of penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae.

An evaluation to determine the optimal methods for the in vitro susceptibility testing of 41 clinical isolates and the ATCC 49619 strain of Streptococcus pneumoniae to penicillin was undertaken. No very major or major interpretive errors were observed with the following test methods and media: agar dilution using either Mueller-Hinton medium with lysed horse blood or Haemophilus test medium; broth dilution using cation-adjusted Mueller-Hinton medium with lysed horse blood, Haemophilus test medium, or Todd-Hewitt medium; and the epsilo-meter test (E-test) using agar containing Mueller-Hinton medium and 5% sheep blood. The disk diffusion method using agar containing Mueller-Hinton medium and 5% sheep blood agar was an effective screening method, requiring confirmation by a dilution susceptibility test method.

Bacteriological Techniques↗
PubMed1993

Pancreatitis in human immunodeficiency virus-infected children receiving dideoxyinosine.

To define predictive or contributory risk factors for pancreatitis in human immunodeficiency virus-infected children receiving dideoxyinosine (ddI), the authors evaluated 95 children, 3 months to 18 years of age, who had received ddI at 60 to 540 mg/m2 per day for a mean of 56 weeks. Pancreatitis developed in 7 patients (7%) but resolved in all upon withdrawal of ddI. Neither age, sex, nor CD4 count at study entry was predictive of pancreatitis, but pancreatitis appeared more likely to develop in hemophiliacs than in other patients (4 of 23 vs 3 of 72). Pancreatitis developed only in patients who received ddI at the highest dose levels (7 of 60 patients who received ddI at a dose > or = 360 mg/m2 per day vs 0 of 35 patients who received < or = 270 mg/m2 per day). Patients in whom pancreatitis developed had received a higher mean daily dose of ddI than patients with normal amylase and lipase levels throughout the study (348 mg/m2 vs 282 mg/m2), but no relationship with the cumulative dose or the duration of ddI therapy was observed. Although a statistically significant relationship between ddI plasma concentration (area under the curve) and pancreatitis was not conclusively demonstrated, as the number of patients in whom pancreatitis actually developed was small, such a relationship may have been obscured.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Ciprofloxacin therapy of experimental endocarditis caused by methicillin-susceptible or methicillin-resistant Staphylococcus aureus.

Ciprofloxacin was more effective (P less than 0.01) than either imipenem or nafcillin therapy of experimental methicillin-susceptible Staphylococcus aureus endocarditis in rabbits after 2 or 3 days of treatment. There was no significant difference between results of treatment of methicillin-susceptible S. aureus experimental endocarditis with ciprofloxacin and results with the combination of nafcillin and gentamicin. Ciprofloxacin was more effective (P less than 0.01) than vancomycin therapy of experimental methicillin-resistant S. aureus endocarditis after 3 days of treatment. After 5 days of treatment, there was no significant difference between the results of treatment of experimental methicillin-resistant S. aureus endocarditis with ciprofloxacin and results with vancomycin.

Animals↗
PubMed1986

Synergistic incorporation of daunorubicin in erythrocytes in the presence of polyene antibiotics. Role of the membrane potential.

The synergistic incorporation into red blood cells of the antitumor compound daunorubicin, in the presence of the polyene antibiotics amphotericin B and vacidin A, depended on the composition of the external medium. Synergism was observed only for concentrations of polyene antibiotics that induce cation permeability. The same synergistic effect was observed with the K+ selective carrier, valinomycin, but this had a different dependence on the external medium composition. By using the membrane probe 3,3'-dipropylthiadicarbocyanine (diS-C3-(5], the synergistic effect was shown to occur under conditions where addition of the ionophores leads to hyperpolarization of the membrane.

Amphotericin B↗
PubMed1985

Interaction of adriamycin with negatively charged model membranes: evidence of two types of binding sites.

The interaction of the antitumor compound adriamycin with negatively charged unilamellar phospholipid vesicles was studied. The negative charges were provided by cardiolipin or phosphatidic acid. By analyzing the changes in the circular dichroism spectrum of adriamycin, we demonstrated the presence of two different spectral patterns corresponding to two different binding sites (I and II) on the vesicles. In site I, the amino sugar of adriamycin is bound to the ionized phosphate of either cardiolipin or phosphatidic acid, and the dihydroxyanthraquinone lies outside the bilayer. In site II, the amino sugar is still bound to the phosphate, but the dihydroxyanthraquinone moiety is embedded in the bilayer. This has been shown by measuring spectroscopically the binding of the aglycon part to an external probe and by measuring the susceptibility of bound adriamycin to reduction by NADH dehydrogenase.

Cardiolipins↗
PubMed1983

Co-operation between metastatic tumor cells and macrophages in the degradation of basement membrane (type IV) collagen.

The co-culture of mouse peritoneal macrophages and Lewis lung carcinoma cells induces the release of a metal-dependent type IV collagen-degrading proteinase which is not produced in detectable amounts by either cell type cultivated alone. Conditioned media of the co-cultures degrade both pepsin-extracted type IV collagen from human placenta and mouse type IV procollagen. Thus macrophages can interact with tumor cells to degrade basement membrane type IV collagen: this might be of importance to allow cancer invasion and metastasis.

Animals↗
PubMed1983

[Experimental reproduction of lactic acidosis in the pony].

One pony has been subjected to the intravenous injections of L-lactic acid. Two other ponies have been trained to intracaecal administration of L-lactic acid or sucrose. The obtained results show that: Intravenous injection of lactic acid increases the concentration of histamin and lactic acid, decreases the level of magnesium and reduces the pressure of carbon dioxide in the blood (the control animals and the treated animals) without the clinical symptoms of lactic acidosis. Intracaecal administration of lactic acid induces a high liberation of histamin in the caecum (the control animals and the treated animals), however, the level of histamin in the blood is not modified. Intracaecal administration of sucrose decreases pH and increases the concentration of lactic acid in the caecum, although, in this case, the accumulation of histamin in the caecum appears only in the non-fasting ponies, the starved animals, and the fed animals, which suggests the necessity of food's proteins for histamin synthesis.

Acidosis↗
PubMed1983

Collagen degradation by metastatic variants of Lewis lung carcinoma: cooperation between tumor cells and macrophages.

Interactions between cancer cells and host macrophages might have important regulatory roles in controlling the expression of the metastatic phenotype, particularly by regulating the production of proteases necessary for tissue invasion. To investigate that possibility, mouse macrophages and Lewis lung carcinoma (LLC) cells from four clonal subpopulations with either low or high metastatic ability were cultured on [14C]collagen (type l)-coated plates. They did not degrade collagen when they were cultured independently on that substrate, but they were induced to do so when macrophages and cancer cells were cultured together. An increased production of neutral collagenase and other neutral protease activities was observed simultaneously. The degree of stimulation of collagen degradation varied according to the cancer cell subpopulation present in the cocultures. For a given LLC cell subpopulation, similar degrees of stimulation of collagen degradation were achieved with either bone marrow-derived or resident peritoneal macrophages, either syngeneic (from C57BL/6 mice) or allogeneic; lower stimulations were obtained with thioglycolate-elicited peritoneal macrophages. Macrophage-conditioned culture media could be substituted for living macrophages to stimulate collagen degradation or collagenase secretion by LLC cells, but LLC cell-conditioned media did not stimulate collagen degradation by macrophages. This suggests that, in the cocultures, collagen degradation is achieved mainly by the cancer cells, not by the macrophages, and that it is induced by a soluble factor, a monokine, produced by the macrophages. That factor might be identical to a recently identified rabbit monokine that stimulates fibroblasts or synovial cells to degrade collagen and proteoglycan and to activate plasminogen, because rabbit macrophage-conditioned media containing that monokine also stimulated collagen degradation by LLC cells.

Animals↗
PubMed1983

Metastatic heterogeneity of cells from Lewis lung carcinoma.

To allow investigations of the role of tumor cell proteases in invasion and metastasis, an attempt was made to obtain well-defined homogeneous populations of Lewis Lung carcinoma cells differing widely in their metastatic potential. From a single Lewis lung carcinoma, a parental line of cells was established and subsequently cloned so as to provide 18 clonal tumor cell lines. These clones differed in their ability to produce spontaneous, macroscopically visible metastases in the lung after i.m. inoculation into syngeneic C57BL/6 mice. Several of them were less metastatic than the parental line. The parental line expressed a metastatic behavior close to that of the high-metastatic cell subpopulations that it contained. There was, within certain limits, a good correlation between the potential for spontaneous lung metastases arising from a primary tumor and that for "artificial" lung colonies obtained after i.v. injection of the Lewis lung carcinoma cells. Although positively correlated with the growth rate of the tumor cells, the metastatic ability of the clones could not be considered as a mere reflection of the proliferation rates of the cells constituting the primary tumors. Differences in metastatic behavior observed among clones persisted in several cases after the cells had been maintained in culture for prolonged periods. However, this stability of the clones in vitro was not absolute. Indeed, some subclones isolated from the low-metastatic clone H122 displayed metastatic abilities which were lower than that of the parent clone. Furthermore, a significant increase in metastatic potential was once observed after a prolonged culture period of that same clone, H122. Thus, new metastatic phenotypes can emerged under in vitro culture conditions. However, the relative rarity of this event suggests that some metastatic heterogeneity already preexisted in vivo among the tumor cells.

Animals↗
PubMed1981

The quaalude scam.

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Ambulatory Care Facilities↗
PubMed1978

Specific antibody-dependent binding of complement component C1q to hapten-sensitized lipid vesicles.

The binding of a component of human complement (C1q) to membrane-bound specific anti-nitroxide antibodies was studied as a function of the physical properties (fluid vs. solid) of vesicle lipids. The antibodies were bound to spin-label lipid haptens in the vesicle membrane. The binding of C1q to the sensitized vesicles shows a maximum as a function of specific IgG concentration. The binding of antibodies and of C1q to the vesicle membrane does not depend strongly on the physical state of the membrane lipids. even at low hapten (0.05 mol%) concentrations. These results are of significance for the understanding of the previously reported effect of lipid physical states on complement depletion.

Antibodies↗
PubMed1978

Visualization of specific antibody and C1q binding to hapten-sensitized lipid vesicles.

Specific IgG antibodies directed against the spin-label nitroxide group present as a lipid hapten in single-compartment lipid vesicles have been visualized by using freeze-etch electron microscopy. Individual "particles" with diameters of the order of 20 nm are identified as single IgG molecules bound to lipid hapten. No significant aggregation of these IgG molecules was observed over a period of 1 hr in a dipalmitoyl phosphatidylcholine vesicle at 22 degrees. Binding of the human complement component C1q results in the formation of large (approximately 50-100 nm) asymmetric particles having a partially resolved substructure that may arise from individual IgG molecules bound to the membranes as well as to C1q. The binding of C1q appears to result in a clustering of membrane-bound IgG molecules. Samples containing a serum factor (perhaps anti-IgG antibodies) exhibit some IgG clustering distinct from that produced by Clq.

Complement C1↗