The Potential of Utilizing Mid-Energy X-Rays for In-Line Phase Sensitive Breast Cancer Imaging

OBJECTIVE

The objective of this study is to demonstrate the potential of utilizing mid-energy x-rays for in-line phase-sensitive breast cancer imaging by phantom studies.

METHODS

The midenergy (50-80kV) in-line phase sensitive imaging prototype was used to acquire images of the contrast-detail mammography (CDMAM) phantom, an ACR accreditation phantom, and an acrylic edge phantom. The low-dose mid-energy phase-sensitive images were acquired at 60 kV with a radiation dose of 0.9 mGy, while the high-energy phase-sensitive images were acquired at 90 kV with a radiation dose of 1.2 mGy. The Phase-Attenuation Duality (PAD) principle for soft tissue was used for the phase retrieval. A blind observer study was conducted and paired-sample T-test were performed to compare the mean differences in the two imaging systems.

RESULTS

The correct detection ratio for the CDMAM phantom for phase-contrast images acquired by the low-dose mid-energy system was 56.91%, whereas images acquired by the high-energy system correctly revealed only 40.97% of discs. The correct detection ratios were 57.88% and 43.41% for phase-retrieved images acquired by the low-dose mid-energy and high-energy imaging systems, respectively. The reading scores for all three groups of objects in the ACR phantom were higher for the mid energy imaging system as compared to the high-energy system for both phase-contrast and phase- retrieved images. The calculated edge enhancement index (EEI) from the acrylic edge phantom image for the mid-energy system was higher than that calculated for the high-energy imaging system. The quantitative analyses showed a higher Contrast to Noise Ratio (CNR) as well as a higher Figure of Merit (FOM) in images acquired by the low-dose mid-energy imaging system.

CONCLUSION

The PAD based retrieval method can be applied in mid-energy system without remarkably affecting the image quality, and in fact, it improves the lesion detectability with a patient dose saving of 25%.

Use of colony stimulating factors (CSF) for primary prophylaxis of chemotherapy-induced neutropenia in community oncology practices to reduce risk of febrile neutropenia (FN)

17013

Background: In addition to proof of efficacy from randomized controlled trials (RCTs), health care decision makers need data on therapy effectiveness, specifically how well an intervention performs in routine practice. While the efficacy of filgrastim and pegfilgrastim in preventing FN has been established in RCTs, their effectiveness in community practice has not been studied. Methods: Data were obtained from medical records of patients treated with chemotherapy for a variety of malignancies in a random sample of 99 US community oncology practices in 2001 and 2003 (before and after FDA approval of pegfilgrastim in 2002). Patients receiving filgrastim or pegfilgrastim and, in 2003, every third patient not treated with a CSF, were consecutively sampled(n=6148). Only those receiving chemotherapy on 3–4 wk cycles were included in this analysis (n=3,744). Primary prophylaxis was defined as receipt of CSF within 3 days of the 1st cycle of chemotherapy. Multivariable logistic regression, adjusted for patient and treatment characteristics and weighted for patient sampling was used to estimate the odds of FN in patients who received primary prophylaxis versus those who were managed expectantly, i.e. patients who received CSF later during chemotherapy or not at all. Results: Of 3744 patients in the study population, 2966 (79%) received a CSF some time during their chemotherapy treatment. In 2003, approximately 18% of patients received CSF primary prophylaxis. Among patients who did not receive primary prophylaxis but received a CSF later during the treatment, 38% initiated CSF in the 1st cycle after day 3. In a multivariate model, increased risk of FN was associated with receiving myelosuppressive chemotherapy (OR 2.19; 95% CI 1.05–4.56) and having 3 or more drugs (vs. 1) in the regimen (OR 2.13; 95% CI 1.09–4.17). Adjusting for patient and treatment characteristics, the relative odds of FN in patients who received CSF primary prophylaxis was 0.70 (95% CI 0.50–0.98) compared with patients who either received CSF later or not at all. Conclusions: In this community practice setting, patients who received CSF primary prophylaxis had significantly lower odds of developing FN than patients managed expectantly.

No significant financial relationships to disclose.

Predictors of febrile neutropenia among Medicare patients with breast, lung and colorectal cancer

9120

Background: Neutropenia and associated impaired immunity is the major dose limiting toxicity for systemic chemotherapy administration. Current guidelines recommend the prophylactic use of G-CSF when the risk of febrile neutropenia (FN) is approximately 20% because it decreases the duration and risk of FN. Advanced age has been identified as a risk factor for FN; however, little is known about the impact of other factors on the incidence of FN in the elderly. Methods: We analyzed SEER-Medicare data on patients diagnosed between 1995 and 2000 with breast, colorectal, and lung cancer, who received chemotherapy within 11 months of diagnosis. We examined a number of factors that might potentially be associated with FN in the first cycle of chemotherapy, including patient demographics, cancer stage at diagnosis, number of myelosupressive chemotherapeutics, frequency of chemotherapy administration, and comorbid conditions, including previous history of anemia and other blood disorders. Outcome was defined as admission to hospital within 30 days of initial chemotherapy administration with neutropenia (ICD9 288.0) coded as an admission diagnosis. Results: Of 18,637 patients who met inclusion criteria 751 (4.0%) had an episode of FN within 30 days of initial chemotherapy administration. In multivariate logistic regression analysis, independent predictors of FN included cancer type (lung cancer, OR 3.77, CI: 1.02–13.9, as compared to breast cancer) and history of blood disorder (OR 1.49, CI: 1.10–2.0), with a trend towards history of COPD (OR 1.19, CI: 0.98–1.44) and three or more myelosupressive agents (OR 4.01, CI: 0.76–21.2, as compared to non-myelosupressive chemotherapy). Initiating chemotherapy less than 1 month after cancer diagnosis was also associated with a higher odds of developing FN (OR 1.88, CI:1.42–2.49 compared to 3 months or more after diagnosis). Discussion: By utilizing the SEER-Medicare dataset we were able to examine predictors of febrile neutropenia in a large population of elderly patients with common malignancies. Knowledge of predisposing factors for neutropenia will allow more tailored prophylactic use of G-CSF in this at-risk population.

No significant financial relationships to disclose.

Effects of cost sharing on care seeking and health status: results from the Medical Outcomes Study

OBJECTIVES

This study sought to determine the effect of cost sharing on medical care use for acute symptoms and on health status among chronically ill adults.

METHODS

Data from the Medical Outcomes Study were used to compare (1) rates of physician care use for minor and serious symptoms and (2) 6- and 12-month follow-up physical and mental health status among individuals at different levels of cost sharing.

RESULTS

In comparison with a no-copay group, the low- and high-copay groups were less likely to have sought care for minor symptoms, but only the high-copay group had a lower rate of seeking care for serious symptoms. Follow-up physical and mental health status scores were similar among the 3 copay groups.

CONCLUSIONS

In a chronically ill population, cost sharing reduced the use of care for both minor and serious symptoms. Although no differences in self-reported health status were observed, health plans featuring cost sharing need careful monitoring for potential adverse health effects because of their propensity to reduce use of care that is considered necessary and appropriate.

Role of cysteinyl residues in sensing Pb(II), Cd(II), and Zn(II) by the plasmid pI258 CadC repressor

The cadCA operon of Staphylococcus aureus plasmid pI258 confers resistance to salts of the soft metals lead, cadmium, and zinc. The operon is regulated by CadC, a member of the ArsR family of metal-responsive transcriptional repressors. In this study the role of the five cysteine residues of CadC in soft metal ion sensing was investigated. Cys-7, Cys-11, Cys-52, Cys-58, and Cys-60 were changed individually to glycine or serine residues. The effect of the cadC mutations was examined in Escherichia coli using a green fluorescent protein reporter system. None of the mutations affected the ability of CadC to repress gfp expression. Neither Cys-11 nor Cys-52 was required for in vivo response to Pb(II), Zn(II), or Cd(II). Cys-7, Cys-58, or Cys-60 mutations each reduced or eliminated soft metal sensing. Wild-type and mutant CadC proteins were purified, and the effect of the substitutions on DNA binding was determined using a restriction enzyme protection assay. Binding of wild-type CadC protected cad operator DNA from digestion at the single SspI site, and the addition of Pb(II), Zn(II), or Cd(II) resulted in deprotection. Chemical modification of the cysteine residues in CadC had no effect on protection but eliminated deprotection. C11G and C52G proteins exhibited wild-type properties in vitro. C7G, C58S, and C60G proteins were able to be protected from SspI digestion but had reduced responses to soft metal ions. The results indicate that Cys-7, Cys-58, and Cys-60 are involved in sensing those soft metals and suggest that they are ligands to Pb(II), Zn(II), and Cd(II).

Liver infarction after laparoscopic cholecystectomy injury to the right hepatic artery and portal vein

A 66-year-old woman presented with fever and right upper quadrant pain 5 weeks after laparoscopic cholecystectomy. Angiogram revealed occlusion of the right hepatic artery and right portal vein which necessitated a right hepatic lobectomy. To our knowledge this has not been previously reported. The patient recovered uneventfully.

Spectroscopic properties of the metalloregulatory Cd(II) and Pb(II) sites of S. aureus pI258 CadC

Staphylococcus aureus pI258 CadC is an extrachromosomally encoded metalloregulatory repressor protein from the ArsR superfamily which negatively regulates the expression of the cad operon in a metal-dependent fashion. The metalloregulatory hypothesis holds that direct binding of thiophilic divalent cations including Cd(II), Pb(II), and Zn(II) by CadC allosterically regulates the DNA binding activity of CadC to the cad operator/promoter (O/P). This report presents a detailed characterization of the metal binding and DNA binding properties of wild-type CadC. The results of analytical ultracentrifugation experiments suggest that both apo- and Cd(1)-CadC are stable or weakly dissociable homodimers characterized by a K(dimer) = 3.0 x 10(6) M(-1) (pH 7.0, 0.20 M NaCl, 25.0 degrees C) with little detectable effect of Cd(II) on the dimerization equilibrium. As determined by optical spectroscopy, the stoichiometry of Cd(II) and Pb(II) binding is approximately 0.7-0.8 mol/mol of wild-type CadC monomer. Chelator (EDTA) competition binding isotherms reveal that Cd(II) binds very tightly, with K(Cd) = 4.3 (+/-1.8) x 10(12) M(-1). The results of UV-Vis and X-ray absorption spectroscopy of the Cd(1) complex are consistent with a tetrathiolate (S(4)) complex formed by four cysteine ligands. The (113)Cd NMR spectrum reveals a single resonance of delta = 622 ppm, consistent with an S(3)(N,O) or unusual upfield-shifted S(4) complex. The Pb(II) complex reveals two prominent absorption bands at 350 nm (epsilon = 4000 M(-1) cm(-1)) and 250 nm (epsilon = 41 000 M(-1) cm(-1)), spectral properties consistent with three or four thiolate ligands to the Pb(II) ion. The change in the anisotropy of a fluorescein-labeled oligonucleotide containing the cad O/P upon binding CadC and analyzed using a dissociable CadC dimer binding model reveals that apo-CadC forms a high-affinity complex [K(a) = (1.1 +/- 0.3) x 10(9) M(-1); pH 7.0, 0.40 M NaCl, 25 degrees C], the affinity of which is reduced approximately 300-fold upon the binding of a single molar equivalent of Cd(II) or Pb(II). The implications of these findings on the mechanism of metalloregulation are discussed.

A comparison of clinical performance of primary care and traditional internal medicine residents

OBJECTIVE

To compare primary care and traditional Internal Medicine residents in their adherence to preventive medicine guidelines, performance in the management of chronic diseases, and utilization of resources.

DESIGN

Prospective cohort study.

SETTING

Urban Internal Medicine residency program.

PARTICIPANTS

Sixteen primary care and 137 traditional Internal Medicine residents who took care of 6,307 patients (a total of 21,002 patient visits in a 1-year period).

MEASUREMENTS

Adherence to preventive medicine guidelines for the screening of breast cancer, cervical cancer, hypercholesterolemia, and colon cancer; admission rates among patients with asthma, chronic pulmonary disease, and diabetes mellitus; four items in the management of diabetes; and resource utilization including the costs for laboratory and radiology tests and number of consultations.

RESULTS

Primary care residents, as compared with traditional residents, adhered to preventive medicine guidelines for a greater proportion of their patients for the following: breast cancer among women aged 52 to 75 years (61% vs. 54%, respectively, P = 0.05); cholesterol screening among patients aged 20 to 64 years (39% vs. 33%, P = 0.007); colon cancer among patients older than 50 years (49% vs. 31%, P = 0.001); and cervical cancer among women aged 20 to 64 years (36% vs. 31%, P = 0.03). There were no differences in hospital admission rates for patients with diabetes or asthma. Total ambulatory care costs for tests, procedures, consults, and office visits were greater for patients of primary care residents ($1,045 vs. $899, P = 0.0001), although total costs per primary care visit were similar between the two patient groups.

CONCLUSIONS

Primary care residents more closely adhered to preventive medicine guidelines but were similar to traditional residents in their management of chronic diseases. Patients of primary care residents had greater ambulatory care costs that were not entirely attributable to greater adherence to preventive medicine guidelines.

Epithelial-matrix interactions : laminin downregulates enterocyte EGF receptor and IGF-I receptor expression

Intestinal crypt cells continuously proliferate to yield functional villus cells which terminally differentiate prior to sloughing into the intestinal lumen. Growth factors and extracellular matrix have been shown to regulate this process. To investigate how these effectors may interact, Epidermal Growth Factor (EGF) receptor and Insulin-like Growth Factor-I (IGF-I) receptor expression was evaluated in IEC-6 cells incubated on laminin or collagen I. EGF receptor and IGF-I receptor expression were decreased in cells grown on laminin. The data suggest that the mechanism by which laminin inhibits enterocyte growth is downregulation of growth factor receptors for important enterocyte mitogens.

Retrograde gastroesophageal intussusception complicating chronic achalasia

We treated a patient with retrograde gastroesophageal intussusception complicating chronic achalasia. Operation consisted of diaphragmatic division in the median plane to facilitate reduction, followed by Heller myotomy and fundoplication for the achalasia. The patient was able to eat normally after recovery.

Partial purification and properties of nicotinamide adenine dinucleotide synthetase from human erythrocytes: evidence that enzyme activity is a sensitive indicator of lead exposure

We have examined properties of nicotinamide adenine dinucleotide (NAD) synthetase from human erythrocytes. The enzyme was found to be cold labile and extremely unstable in crude hemolysate, with complete loss of activity occurring after 24 hours at 4 degrees C. However, maintenance of crude hemolysate at 20 to 25 degrees C in the presence of EDTA and KCl increased NAD synthetase stability substantially (half-life = 10 days). Using these conditions, NAD synthetase was purified 3,100-fold with a 29% yield using DEAE-cellulose column chromatography, ammonium sulfate fractionation, and dialysis. The apparent Michaelis-Menten constants for nicotinic acid adenine dinucleotide (NAAD), adenosine triphosphate, Mg2+, glutamine, and K+ were 0.108, 0.154, 1.36, 2.17, and 8.32 mmol/L, respectively. The pH optimum ranged between 6.8 and 7.4, and the molecular weight was estimated to be 483 +/- 5 Kd. The enzyme was markedly inhibited by Pb2+ and Zn2+, with concentrations necessary for 50% inhibition of activity of 1.3 and 2.0 mumol/L, respectively. The incubation of intact red blood cells with lead followed by rigorous washing to remove lead abolished nearly all NAD synthetase activity. In contrast, glucose-6-phosphate dehydrogenase activity, which is not sensitive to lead, was unaffected, whereas pyrimidine 5'-nucleotidase activity, which is sensitive to lead, was decreased 30% to 50% under these conditions. More importantly, patients with lead overburden (34 to 72 micrograms Pb2+/dL blood) all had markedly decreased NAD synthetase activity. These data together with other results suggest that erythrocyte NAD synthetase activity is a sensitive indicator of lead exposure in humans.

Impaired erythrocyte phosphoribosylpyrophosphate formation in hemolytic anemia due to pyruvate kinase deficiency

RBCs from patients with hemolytic anemia due to pyruvate kinase (PK) deficiency are characterized by a decreased total adenine and pyridine nucleotide content. Because phosphoribosylpyrophosphate (PRPP) is a precursor of both adenine and pyridine nucleotides, we investigated the ability of intact PK-deficient RBCs to accumulate PRPP. The rate of PRPP formation in normal RBCs (n = 11) was 2.89 +/- 0.80 nmol/min.mL RBCs. In contrast, the rate of PRPP formation in PK-deficient RBCs (n = 4) was markedly impaired at 1.03 +/- 0.39 nmol/min.mL RBCs. Impaired PRPP formation in these cells was not due to the higher proportion of reticulocytes. To study the mechanism of impaired PRPP formation, PK deficiency was simulated by incubating normal RBCs with fluoride. In normal RBCs, fluoride inhibited PRPP formation, caused adenosine triphosphate (ATP) depletion, prevented 2,3-diphosphoglycerate (DPG) depletion, and inhibited pentose phosphate shunt (PPS) activity. These results together with other data suggest that impaired PRPP formation is mediated by changes in ATP and DPG concentration, which lead to decreased PPS and perhaps decreased hexokinase and PRPP synthetase activities. Impaired PRPP formation may be a mechanism for the decreased adenine and pyridine nucleotide content in PK-deficient RBCs.

Metabolism of natural and synthetic corticosteroids in relation to their effects on mouse fetuses

14C-glucose uptake by mouse fetuses was reduced by doses of dexamethasone, 200 mug or more, which over 2 days caused fetal death. Uptake by strain C57B1/6J greater than A/J greater than SWV. Corticosterone or cortisol, 4 mg, caused neither reduced uptake nor fetal death. These differences occurred despite similar maternal hyperglycemia in all cases. Recovery of 3H-steroid after 15 min, total and unchanged steroid per gram fetal tissue was: corticosterone 1.7 and 0.3%; dexamethasone 0.12 and 0.06% of the dose. Rapid metabolism of corticosterone apparently prevents accumulation in fetal tissue sufficient to evoke a response under these conditions.

Subcellular distribution of glucocorticoid receptors in mouse fibroblasts

Mouse fibroblasts contain a macromolecular binding component (receptor) which binds glucocorticoids specifically and with high affinity. This study shows that there are three different cellular forms of bound receptor and that it is experimentally possible to markedly alter the subcellular distribution of these three forms. Cells incubated with (3H)triamcinolone acetonide were broken after hypotonic shock and a 7000g hypotonic supernatant was obtained; the pellet was extracted with 0.3 M KCl, yielding a nuclear extract; the remaining pellet was resuspended in water, sonicated, and assayed for "nuclear residual" (i.e., nonextractable) radioactivity. If whole cells are incubated at 0 degrees in a growth medium, almost all of the bound steroid is located in the hypotonic supernatant fraction. Incubation at 37 degrees produces a shift of the steroid-bound macromolecule into the nuclear extractable form, while omission of glucose and addition of KCN at 37 degrees markedly increase the nuclear residual form at the expense of both the nuclear-extractable and supernatant forms. Since DNase treatment of chromatin liberates a soluble steroid-receptor complex, we believe that the nuclear residual form may be steroid-receptor complex tightly bound to chromatin. We propose a model suggesting that an energy-requiring process is required to generate free receptor from the chromatin complex to complete the normal cellular recycling system.

Studies on corticosterone-receptor complexes from mouse placenta

The in vitro binding of radioactive steroids to components of mouse placental nuclei and cytoplasm was investigated using Sephadex or charcoal to remove unbound steroid. Specificity was indicated in competition experiments using excess unlabelled competing steroids. Only the active glucocorticoids formed complexes that could be isolated from the nucleus. The binding properties of the cytoplasmic steroid–receptor complex were studied. From the time course of binding the complex was shown to be more stable at 0° than at 37°, and the distribution of receptors in the cytosol appeared to be homogeneous. The complex was labile to heat and to proteolytic digestion but did not appear to be affected by nucleases or sulfhydryl reagents. Kinetic analysis revealed the presence of high affinity specific binding sites with a dissociation constant of 17.5 nM and a receptor site concentration of 0.26 pmol/mg protein. The corticosterone isolated from nuclear complexes and dexamethasone from cytoplasmic complexes were identified by chromatography and by cocrystallization as the unchanged steroid in each case.

Quantitative radioautography of sugar transport in intestinal biopsies from normal humans and a patient with glucose-galactose malabsorption

Both galactose accumulation and phlorizin binding by columnar epithelial cells have been investigated in vitro with a recently developed technique for high-resolution, plastic-section radioautography which is particularly suited to small quantities of biopsy tissue. Grain density analysis of the radioautographs provides definitive support for the view that the cellular mechanisms underlying glucose-galactose absorption in laboratory animals are fully applicable to the small intestine of man. Even the number of sugar carriers at the microvillar membrane appears similar and the major quantitative difference, lower affinity for phlorizin in man, correlates with the finding that phlorizin is also a less potent inhibitor of uphill, galactose transport at the microvilli. In addition, radioautographs of biopsies taken 2 yr apart from a patient with glucose-galactose malabsorption provide evidence that the cellular defect in this inborn error of transport is a persistent reduction in the number of functioning sugar carriers at the microvillar membrane.