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Biomedical subjects

I Ostfeld

Publications and source records attributed to I Ostfeld.

15 recordsLinked to original sources

The significance of Acinetobacter baumannii bacteraemia compared with Klebsiella pneumoniae bacteraemia: risk factors and outcomes.

Risk factors and outcomes for patients with nosocomial Acinetobacter baumannii bacteraemia were compared with those for patients with nosocomial Klebsiella pneumoniae bacteraemia in a single centre in Israel between 2000 and 2003. Data were collected retrospectively through patient chart review. In total, 112 patients with A. baumannii bacteraemia and 90 patients with K. pneumoniae bacteraemia were identified. A. baumannii was significantly associated with poorer performance status, mechanical ventilation, presence of devices, prior treatment with carbapenems, pneumonia as the source of infection and inappropriate empirical antibiotic treatment. All-cause 30-day mortality was higher for A. baumannii bacteraemia compared with K. pneumoniae bacteraemia (61.6% vs 38.9%, P=0.001). Variables significantly associated with mortality at the univariate level (P<0.1) were entered into a multi-variable logistic regression model for mortality. A. baumannii remained significantly associated with mortality when adjusted for all other risk factors (odds ratio 3.61, 95% confidence interval 1.55-8.39). This result did not change when the analysis was repeated for subgroups of less severely ill patients, i.e. those who were not ventilated and those who did not present with septic shock. These results support the view that nosocomial bacteraemia due to A. baumannii is associated with increased mortality.

Acinetobacter Infections↗

Acinetobacter baumannii: emergence and spread in Israeli hospitals 1997-2002.

The incidence of multi-drug-resistant Acinetobacter baumannii bloodstream infections (BSIs) increased two- to four-fold in three Israeli hospitals between 1997 and 2002, accounting for 3.5-18% of all hospital-acquired BSIs. This was associated with increasing carbapenem resistance reaching 35-54%, and by a dramatic increase in carbapenem consumption. In-hospital fatality rates ranged between 47% and 58% and were significantly higher than those seen with other nosocomial Gram-negative pathogens. A. baumannii was not restricted to intensive care units, but had spread to all hospital wards. Multi-drug-resistant A. baumannii has the potential to reach endemicity in hospitals and warrants more vigorous and innovative efforts to limit its spread.

Acinetobacter Infections↗

Characteristics of candidaemia with Candida-albicans compared with non-albicans Candida species and predictors of mortality.

Candidaemia due to non-albicans Candida species is increasing in frequency. We describe 272 episodes of candidaemia, define parameters associated with Candida albicans and other Candida species, and analyse predictors associated with mortality. Patients with C. albicans (55%) had the highest fatality rate and frequently received immunosuppressive therapy, while patients with Candida parapsilosis (16%) had the lowest fatality and complication rates. Candida tropicalis (16%) was associated with youth, severe neutropenia, acute leukaemia or bone marrow transplantation, Candida glabrata (10%) was associated with old age and chronic disease, and Candida krusei (2%) was associated with prior fluconazole therapy. The overall fatality rate was 36%, and predictors of death by multi-variate analysis were shock, impaired performance status, low serum albumin and congestive heart failure. Isolation of non-albicans Candida species, prior surgery and catheter removal were protective factors. When shock was excluded from analysis, antifungal therapy was shown to be protective. Unlike previous concerns, infection with Candida species other than C. albicans has not been shown to result in an increased fatality rate.

Adolescent↗

A case of cellulitis complicating Campylobacter jejuni subspecies jejuni bacteremia and review of the literature.

Infection with Campylobacter species is a predominant cause of food-borne gastroenteritis in the industrialized world. Bacteremia is detected in <1% of patients with diarrhea, mainly in immunocompromised hosts or those in the extremes of age. Reported here is the case of a 78-year-old, immunocompromised male patient with Campylobacter jejuni subsp. jejuni bacteremia complicated by cellulitis. The infection was characterized by a protracted course with several recurrences and refractoriness to multiple antibiotic regimens, responding only to a prolonged course of meropenem treatment. The frequency of cellulitis as reflected in previously reported series of Campylobacter bacteremia and the clinical characteristics of this difficult-to-treat infection are reviewed.

Aged↗

Truncus arteriosus with anomalous pulmonary venous connection.

The anatomic, diagnostic, and management findings of 6 patients with truncus arteriosus and anomalous pulmonary venous connections are described. Additional risk factors indicative of poor prognosis were found in 3 of 4 patients with truncus arteriosus and totally anomalous pulmonary venous connection and in 1 patient with partially anomalous pulmonary venous connection.

Cause of Death↗

Lipoprotein(a), plasmin modulation, and atherogenesis.

Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein however the mechanisms by which Lp(a) promote the atherosclerotic process are not clear. The apolipoprotein(a) portion of Lp(a) shares partial homology with plasminogen, a finding that has stimulated numerous studies. Lp(a) binds to fibrin and the affinity between fibrin surfaces and Lp(a) appears to be related to the state of oxidation of the lipoprotein particle. Lp(a) also effects fibrin-dependent plasminogen activation. Recent findings suggest that dependent plasminogen activation. Recent findings suggest that depending upon the in vitro conditions, Lp(a) either promotes or inhibits plasmin formation. Lp(a) also inhibits cell-surface dependent plasmin generation that is associated with an inhibition of transforming growth factor-beta (TGF-beta) production in cell coculture systems. Lp(a) stimulates smooth muscle cell migration and proliferation as a secondary response to this decrease in TGF-beta concentration. Studies in transgenic mice containing the human apolipoprotein(a) gene, document that both plasmin and TGF-beta formation in the media of the aorta is markedly decreased in the presence of apo(a). Thus the atherogenicity of Lp(a) may be mediated, in part, through its modulation of plasmin and TGF-beta production in the blood vessel wall.

Adult↗

Treatment of systemic lupus erythematosus by prolonged administration of high dose intravenous immunoglobulin: report of 2 cases.

Two patients with life threatening manifestations of systemic lupus erythematosus (SLE), unresponsive to corticosteroid and immunosuppressive therapy, were treated with high dose intravenous immunoglobulin (IVIG). Following IVIG therapy, lupus pneumonitis and encephalitis in the first patient, and lupus nephritis in the second patient, resolved. Continuous treatment with IVIG, every 4 weeks for up to 20 months induced a prolonged clinical and laboratory remission. Treatment with cytotoxic agents was stopped, and the dosage of corticosteroids lowered. Exacerbation of lupus nephritis occurred in the second patient after 10 months of IVIG therapy. We suggest that prolonged use of high dose IVIG may be a useful therapy for acute exacerbations of SLE and for inducing prolonged remissions.

Adult↗

Lupus anticoagulant antibodies inhibit collagen-induced adhesion and aggregation of human platelets in vitro.

The effect of circulating lupus anticoagulant on platelet interaction with collagen and other proteins was tested, with the aim of understanding the role of membrane phospholipids in platelet function. Plasma samples from 26 systemic lupus erythematosus (SLE) patients, containing circulating lupus anticoagulant (LAC), were examined for their effect on adhesion and aggregation of normal human platelets. We find that SLE plasma, but not normal plasma, inhibits platelet adhesion to collagen in a concentration-dependent manner. At a plasma concentration of 1% the inhibition was 73 +/- 9% (mean +/- SD). In sharp contrast, there was no effect on platelet adhesion to fibronectin. Purified IgG from the same plasma samples also had an inhibitory effect. At 15 micrograms/ml (comparable in IgG concentration to 0.1% plasma) it inhibited adhesion to collagen by 33 +/- 11%. Inhibition could be abolished by preincubation of the LAC-containing plasma with cardiolipin (CL), phosphatidylinositol (PI), and, to a lesser extent, phosphatidylserine (PS) but not with phosphatidylcholine (PC) or phosphatidylethanolamine (PE). Inhibition could also be abolished by preincubation of the LAC-containing plasma with a 10-fold excess of washed normal platelets. The effect of 1% LAC plasma on platelet aggregation was as striking, showing 79 +/- 26% inhibition of collagen-induced aggregation, and it could also be abolished by preincubation of the LAC plasma with cardiolipin. In contrast, the effect of LAC plasma on thrombin-induced aggregation was rather modest. Our results indicate that antiphospholipid antibodies interfere with platelet adhesion and stimulation by collagen in vitro and point to an important role of external plasma membrane phospholipids, particularly PI, in collagen-induced platelet activation.

Adult↗

Detection of aggregated leukocytes in the circulating pool during stress-demargination is not necessarily a result of decreased leukocyte adhesiveness.

Leukocyte endothelial interactions are essential for a normal immune response. It is known that this response is influenced by stress and that the latter induces demargination. We examined the question of whether stress demargination results from a decreased state of leukocyte adhesiveness. Included were various volunteers and patients under different degrees of stress. 66 young athletes before beginning their daily exercises, 67 middle-aged healthy volunteers, 25 patients before ergometry for evaluation of chest pain, 75 patients who were referred to the emergency room with chest pain without ischemia/infarction, 78 patients with ischemia/infarction, 65 patients with minor trauma, 25 with a fracture and 12 with polytrauma. The leukocyte adhesiveness/aggregation (LAA) values were measured with a direct slide test. The respective LAA values were 7.4 +/- 4.7, 6.3 +/- 4.4, 5.8 +/- 3.6, 5.2 +/- 3.5, 10.8 +/- 8.5, 9.1 +/- 5.8, 12.2 +/- 6.6 and 19 +/- 12.6% of aggregated leukocytes. We conclude that an increase in aggregated white blood cells can be detected in the circulating pool during major stress. It is therefore suggested that stress demargination is not necessarily a result of diminished leukocyte adhesiveness.

Adolescent↗

Aggregation of white cells and C-reactive protein: relation between these two indices in acute phase reaction.

The association between aggregates of leucocytes in blood drawn from patients with various inflammatory conditions and the serum concentration of C-reactive protein (CRP) was examined: serum concentration of CRP might contribute to the development of cellular aggregations. A total of 213 patients with various inflammatory or necrotic conditions were examined (including 31 women with normal pregnancy and 59 controls). A significant correlation between the degree of leucocyte aggregation and CRP concentration was noted in patients with bacterial infections and in a group of patients with various inflammatory conditions. In contrast, there was no correlation between the extent of leucocyte aggregation and CRP concentrations in patients with viral infections, malignancies, or pregnancy. The presence or absence of aggregated leucocytes can help in differentiating between the respective bacterial or viral infections. The serum concentrations of CRP were increased in both types of infection, although when a quantitative CRP assay was used, considerably higher concentrations were detected in bacterial diseases.

Acute-Phase Reaction↗