[What is the significance of extended spectrum betalactamases in clinical practice?]

Extended spectrum betalactamases (ESBL) confer resistance to most commonly used betalactam antibiotics. Their emergence in Gram negative bacteria was observed after the widespread use of cephalosporins and quinolones. They can cause severe infections in the hospital as well as in the community. Carbapenems remain the first choice of treatment for these infections. Appropriate use of antibiotics could decrease the spread of ESBLs.

Antiphospholipid antibodies in haemophilia patients with severe bleeding tendency: cause, consequence or a consequential cause?

The prevalence, cause and the impact of antiphospholipid antibodies (APAs) on the clinical severity in haemophilia patients is poorly studied. We studied 72 severe seronegative (negative for HIV, HBsAg, HCV) haemophilia patients for the presence of four common APAs. Twenty-six (36.1%) were positive for any one of the APAs studied of which eight were positive only for anticardiolipin antibodies, three for beta2 glycoprotein (beta2GP1), four for prothrombin (PT) and six for anti annexin antibodies. Remaining six patients showed multi-specific antibodies. Further, clinically severe haemophilia patients (n = 37) showed higher prevalence of APAs as compared with the clinically milder group (n = 35) suggesting that these antibodies do not contribute in alleviating the clinical severity in haemophilia patients as has been observed with other inherited thrombophilia markers. The study of in vitro thrombin generation showed a higher endogenous thrombin potential (ETP) i.e. almost normal, in case of beta2GP1-positive patients as compared with patients with other types of APAs. High prevalence of APAs in clinically severe haemophilia patients may be a consequence of continuing tissue damage in the clinically severe group; as in India, clotting factor concentrates cannot be used ad lib because of financial constraints. Higher thrombin-generating potential in case of patients positive for beta2GP1 did not seem to have any impact on the clinical severity of haemophilia patients.

Survival of patients (pts) treated with high-dose radiotherapy (RT) and concurrent chemotherapy for unresectable non-small cell lung cancer (NSCLC)

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Background: NCCTG N0028 was a trial that determined the MTD of RT that could be given with carboplatin & paclitaxel was 74 Gy/34 fractions. This secondary analysis was performed to determine the survival of pts treated on this trial. Methods: Eligible pts had medically or surgically unresectable NSCLC, PS=0–1, weight loss <10% in the prior 3 months(mo), no prior therapy, adequate laboratory & pulmonary functions. Included were 25 pts with clinical stages I (4pts), II (1 pt), IIIa (12 pts), & IIIb (8 pts). Treatment included: weekly I.V. paclitaxel (50mg/m2) & carboplatin (AUC=2) during RT. The RT included 2 Gy daily to an initial dose of 70 Gy. The total dose was increased in 4 Gy increments until the MTD was determined. RT was delivered with 3-D treatment planning but no elective nodal RT. Three pts received 70 Gy, 18 pts received 74 Gy, & 4 pts received 78Gy. Results: Pts were followed until death or from 10–67 mo (median: 28mo) in those alive at last evaluation. The median survival (MS) of the entire cohort was 42mo. The 5 stages I-II pts had a MS of 53 mo & the 20 stage III pts had MS of 42mo. Conclusions: Standard dose RT is unable to sterilize disease in the majority of pts with unresectable NSCLC. While the addition of chemotherapy has significantly improved survival of these pts, the MS is generally 15–24 mo. These preliminary results suggest higher than standard doses of RT may improve disease control & prolong survival. A phase III trial comparing standard-dose RT(60Gy) to high-dose RT (74Gy) is open and should more definitively address the issue of RT dose with concurrent chemotherapy for unresectable NSCLC. Future technological improvements in imaging & targeting will provide methods to safely administer even greater RT doses which will likely further improve disease control.

No significant financial relationships to disclose.

Placental histomorphology in unexplained foetal loss with thrombophilia

BACKGROUND & OBJECTIVES

Acquired and genetic thrombotic conditions, both organ and non organ specific, are associated with increased foetal wastage. This study was carried out to examine the placenta from women with abnormal pregnancies and a history of unexplained foetal loss, and to associate with maternal thrombophilia status.

METHODS

Placentas from eight women with history of unexplained foetal loss were analyzed for histopathological characteristics. All the women were simultaneously screened for the common acquired and genetic thrombophilia markers i.e., lupus anticoagulants ( LA), IgG / IgM antibodies for anticardiolipin (ACA), beta2 glycoprotein 1 (beta2GPI) and annexin V, protein C (PC), protein S (PS), antithrombin III (AT III), factor V Leiden ( FVL) mutation, prothrombin (PT) gene G20210A, methylene tetrahydrofolate reductase (MTHFR) C 677T, endothelial protein C receptor (EPCR) 23 bp insertion and plasminogen activator inhibitor ( PAI-1 4G/5G) polymorphisms

RESULTS

Six of eight women were positive for one or more thrombophilia markers. The placenta in all the cases except one, showed the characteristic features of infarct fibrin deposition and calcification. Among two women who were negative for thrombophilia, one showed clear evidence of thrombus in the placental sections while the other did not show any characteristic infarcts in the placental sections.

INTERPRETATION & CONCLUSION

Our findings showed that the histopathological examination of the placentas confirmed thrombophilia as the aetiological cause of thrombosis in 6 of the 8 women. The presence of thrombus in a negative thrombophilia woman suggests yet unidentified thrombophilia markers or probably non-haemostatic factors causing thrombosis.

The lysyl oxidase pro-peptide attenuates fibronectin-mediated activation of the focal adhesion kinase and p130Cas in breast cancer cells

Abstract #4073

The lysyl oxidase (LOX) gene encodes an enzyme (LOX) critical for extracellular matrix maturation. The LOX gene has also been shown to inhibit the transforming activity of Ras oncogene signaling. In particular, the pro-peptide domain (LOX-PP) of the secreted precursor protein (Pro-LOX) was found to inhibit the transformed phenotype of breast, lung and pancreatic cancer cells. LOX-PP expression in these carcinoma cells reverted Her-2/neu- and Ras-mediated epithelial to mesenchymal transition (EMT), leading to increased expression of E-cadherin and γ-catenin, and reduced levels of Snail, vimentin and/or BCL2, as well as invasion through Matrigel. Furthermore, LOX-PP expression reduced tumor formation of Her-2/neu driven breast cancer cells in a xenograft model. However, the mechanism of action remains to be determined. Here the ability of LOX-PP to attenuate the integrin signaling pathway in NF639 breast cancer cells driven by Her-2/neu, which signals via Ras, was tested. Ectopic Pro-LOX and LOX-PP expression inhibited fibronectin-stimulated protein tyrosine phosphorylation. Importantly, phosphorylation of the focal adhesion kinase (FAK) on Tyr397 and Tyr576, and the activation of its downstream target p130Cas were substantially reduced. Furthermore, these changes were also reflected by a reduced amount of endogenous p130Cas in the Triton X-100 insoluble protein fraction, and attenuation of fibronectin-activated haptotaxis. Interestingly, expression of mature LOX enzyme enhanced fibronectin-stimulated integrin signaling. Of note, treatment with recombinant LOX-PP reduced haptotaxis of NF639 and human MDA-MB-231 and Hs578T breast cancer cells. Thus, the tumor suppressor function of LOX-PP is likely mediated, in part, by blocking integrin signaling and fibronectin-stimulated cell migration.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4073.

Heart rate recovery: validation and methodologic issues

OBJECTIVES

The goal of this study was to validate the prognostic value of the drop in heart rate (HR) after exercise, compare it to other test responses, evaluate its diagnostic value and clarify some of the methodologic issues surrounding its use.

BACKGROUND

Studies have highlighted the value of a new prognostic feature of the treadmill test-rate of recovery of HR after exercise. These studies have had differing as well as controversial results and did not consider diagnostic test characteristics.

METHODS

All patients were referred for evaluation of chest pain at two university-affiliated Veterans Affairs Medical Centers who underwent treadmill tests and coronary angiography between 1987 and 1999 as predicted after a mean seven years of follow-up. All-cause mortality was the end point for follow-up, and coronary angiography was the diagnostic gold standard.

RESULTS

There were 2,193 male patients who had treadmill tests and coronary angiography. Heart rate recovery at 2 min after exercise outperformed other time points in prediction of death; a decrease of <22 beats/min had a hazard ratio of 2.6 (2.4 to 2.8 95% confidence interval). This new measurement was ranked similarly to traditional variables including age and metabolic equivalents but failed to have diagnostic power for discriminating those who had angiographic disease.

CONCLUSIONS

Heart rate at 1 or 2 min of recovery has been validated as a prognostic measurement and should be recorded as part of all treadmill tests. This new measurement does not replace, but is supplemental to, established scores.

Acute HIV infection: impact on the spread of HIV and transmission of drug resistance

OBJECTIVE

To assess the impact of primary HIV infection (PHI) on the spread of HIV and the temporal trends in transmission of HIV drug resistance between 1996 and 1999 in Switzerland.

METHODS

Sequencing of the genes for reverse transcriptase (RT) and protease was performed for 197 individuals with documented PHI. Phylogenetic analyses were confronted with epidemiological data.

RESULTS

Significant clustering was demonstrated for 29% of the RT sequences. All these cases occurred closely together in place and time; contact tracing demonstrated transmission at the time of PHI in 30% of them. Genotypic drug resistance was detected in 8.6% of PHI individuals in 1996, 14.6% in 1997, 8.8% in 1998 and 5.0% in 1999. Drug-resistant variants were identified in 11.3% of individuals infected by homosexual contacts, 6.1% by heterosexual contacts, 13% of intravenous drug users and more frequently in men (10.4%) than women (2.6%). Potential factors involved in the recent decrease of transmission of drug-resistant variants include increase of HIV non-B subtypes from 23% in 1996 to 35% in 1999 (only one non-B subtype had resistance mutations) and a steady increase of patients with undetectable viraemia as documented in Swiss HIV Cohort Study (10% in 1996 vs 53% in 1999).

CONCLUSIONS

Phylogenetic and epidemiological analyses underline the impact of PHI in the spread of HIV. Moreover, this study indicates that drug resistance transmission may have decreased recently in Switzerland through the increased frequency of infection with HIV non-B subtypes and the steady increase of patients with undetectable viraemia.

Paclitaxel and concurrent radiation for locally advanced pancreatic cancer

PURPOSE

To determine the activity and toxicity of paclitaxel and concurrent radiation for pancreatic cancer.

METHODS AND MATERIALS

Forty-four patients with locally unresectable pancreatic cancer were studied. Patients received paclitaxel, 50 mg/m(2) by 3 h i.v. (IV) infusion, weekly, on Days 1, 8, 15, 22 and 29. Radiation was administered concurrently to a total dose of 50.4 Gy, in 1.80 Gy fractions, for 28 treatments.

RESULTS

Nausea and vomiting were the most common toxicities, Grade 3 in five patients (12%). Two patients (5%) had Grade 4 hypersensitivity reactions to their first dose of paclitaxel. Of 42 evaluable patients, the overall response rate was 26%. The median survival was 8 months, and the 1-year survival was 30%.

CONCLUSION

Concurrent paclitaxel and radiation demonstrate local-regional activity in pancreatic cancer. Future investigations combining paclitaxel with other local-regional and systemic treatments are warranted.

Decay of cell-associated HIV-1 DNA correlates with residual replication in patients treated during acute HIV-1 infection

OBJECTIVES

To evaluate the decay rate of cell-associated HIV-1 RNA and DNA and to identify factors associated with residual viral load in patients treated at the time of primary HIV-1 infection.

PATIENTS

A group of 15 patients adherent to highly active antiretroviral therapy (HAART) with sustained undetectable HIV-1 viremia for at least 24 months.

METHODS

Viremia, cell-associated HIV-1 RNA and DNA in blood and lymph node mononuclear cells were measured using ultrasensitive assays.

RESULTS

Viremia decreased rapidly in all patients; HIV RNA remained < 3 copies/ml in nine patients and fluctuated between 3 and 50 copies/ml in five patients and between 50 and 200 copies/ml in one patient. Decay rates of cell-associated RNA and DNA presented an inflexion point at 1 and 3 months, respectively: first-phase mean half-lives were 0.15 and 0.84 months, respectively, and second-phase mean half-lives were 13.7 and 6.6 months, respectively (95% confidence interval 4.4-13.8). The second phase decay rates were markedly slower, with a DNA decay rate that was highly associated with the mean levels of cell-associated RNA measured in blood from 6 to 33 months (P= 0.001) and in lymph nodes collected at 14 months (P= 0.02).

CONCLUSIONS

The clearance of HIV-1 infected cells is correlated with the extent of viral replication as measured by cell-associated RNA levels in both blood and lymph nodes. Quantification of cell-associated RNA and DNA further defines treatment efficacy in 'aviremic' patients.

Activity of voriconazole combined with neutrophils or monocytes against Aspergillus fumigatus: effects of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor

Voriconazole (VCZ) was tested for antifungal activity against Aspergillus fumigatus hyphae alone or in combination with neutrophils or monocytes. Antifungal activity was measured as percent inhibition of hyphal growth in assays using the dye MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] or XTT [2, 3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxa nilide ]. With both assays, VCZ inhibited hyphal growth at concentrations of <1 microgram/ml and was almost as active as amphotericin B. VCZ (0.6 microgram/ml) was sporicidal, as was amphotericin B (0.4 microgram/ml). With both the MTT and XTT assays, neutrophils alone inhibited hyphae; when combined with VCZ, there was additive activity. Both granulocyte colony-stimulating factor- and granulocyte-macrophage colony-stimulating factor (GM-CSF)-treated polymorphonuclear neutrophils (PMN) had enhanced inhibition of hyphal growth. Moreover, such treatment of PMN also enhanced the collaboration of PMN with VCZ. Monocytes inhibited hyphal growth. When VCZ was combined with monocytes or monocytes were treated with GM-CSF, inhibition was significantly increased, to similar levels. However, the combination of VCZ with GM-CSF treatment of monocytes did not significantly increase the high-level inhibition by monocytes with either agent alone.

Activity of voriconazole, a new triazole, combined with neutrophils or monocytes against Candida albicans: effect of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor

The antifungal activity of voriconazole (VCZ) was tested against Candida albicans in the absence or presence of polymorphonuclear neutrophils (PMN) or monocytes. In some experiments, VCZ was compared to fluconazole (FCZ). On a weight basis, VCZ was 10-fold more efficacious than FCZ against C. albicans Sh27. Against an FCZ-resistant isolate, VCZ at 1 microg/ml produced the same fungistasis as FCZ at 20 microg/ml. VCZ at 0.1 microg/ml collaborated with PMN for enhanced killing to the same extent as FCZ at 1.0 microg/ml. Granulocyte-colony-stimulating factor (G-CSF) enhanced the candidacidal activity of PMN, and it increased the collaboration of PMN with VCZ for killing. Granulocyte-macrophage (GM)-CSF also significantly enhanced both the killing by PMN and the collaboration of PMN with VCZ for killing. VCZ collaborated with GM-CSF-activated monocytes [corrected] for enhanced killing of C. albicans Sh27, and GM-CSF increased this collaboration. Taken together, these data show that VCZ is more potent than FCZ against C. albicans isolates, alone and in collaboration with PMN or monocytes for enhanced killing. In addition, G-CSF- or GM-CSF-activated PMN and monocytes have enhanced collaboration with VCZ compared to that of unstimulated phagocytes with VCZ.

Thin-walled lung cavities and cysts due to AIDS-related pulmonary infection

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Comparative studies on acid cholesterol esterase in renal blood vessels and aorta of control and hypercholesterolemic rabbits

Decreased acid cholesterol esterase has been linked to cholesteryl ester accumulation and may be fundamental in the development of atherosclerosis. The present study compared cholesterol esterase activity with the accumulation of cholesterol and its esters in aorta, renal artery and renal preglomerular microvessels. Tissue was obtained from white New Zealand rabbits fed either a control or 2%-cholesterol diet for 1 month. Cholesterol esterase was increased in microvessels from cholesterol-fed animals when compared to aorta and renal artery. Cholesterol feeding generally produced an increase in cholesterol and cholesteryl ester accumulation in all vascular tissues. The percent distribution of esterified/total cholesterol in renal microvessels was decreased consistent with the concomitant increase in cholesterol esterase. In contrast, aorta and renal artery exhibited an increase in cholesterol and cholesteryl ester accumulation and an increase in the percent of esterified cholesterol consistent with a decrease in acid cholesterol esterase after cholesterol feeding. The data suggest that renal microvessels, when compared to aorta and renal artery, may be relatively protected from developing atherosclerotic microvascular lesions through an organ-specific increase in acid cholesterol esterase activity.