Calibration of an extreme-ultraviolet transmission grating spectrometer with synchrotron radiation

The responsivity of an extreme-ultraviolet transmission grating spectrometer with silicon photodiode detectors was measured with synchrotron radiation. The spectrometer was designed to record the absolute radiation flux in a wavelength bandpass centered at 30 nm. The transmission grating had a period of 200 nm and relatively high efficiencies in the +1 and the -1 diffraction orders that were dispersed on either side of the zero-order beam. Three photodiodes were positioned to measure the signals in the zero order and in the +1 and -1 orders. The photodiodes had aluminum overcoatings that passed the desired wavelength bandpass centered at 30 nm and attenuated higher-order radiation and wavelengths longer than approximately 80 nm. The spectrometer's responsivity, the ratio of the photodiode current to the incident radiation power, was determined as a function of the incident wavelength and the angle of the spectrometer with respect to the incident radiation beam. The spectrometer's responsivity was consistent with the product of the photodiode responsivity and the grating efficiency, both of which were separately measured while removed from the spectrometer.

Relationship between IgM antibody to human cytomegalovirus, virus load, donor and recipient serostatus, and administration of methylprednisolone as risk factors for cytomegalovirus disease after liver transplantation

A retrospective study was performed on a selected cohort of 40 liver transplant recipients derived from the previous prospective follow-up of 162 liver transplant patients. The criterion for selection of this cohort was the presence of human cytomegalovirus (HCMV) DNAemia after transplantation, as determined by qualitative polymerase chain reaction (PCR). These 40 patients were followed longitudinally by quantitative PCR and by the new recombinant antigen-based AxSYM immunoassay for IgM to HCMV. The detection of IgM to CMV after transplantation was significantly associated with the development of HCMV disease in patients who had evidence of active HCMV replication in the blood by PCR (P=.01). On the basis of multivariate logistic regression analyses, the maximum titer of IgM detected after transplantation was a risk factor that was independent of augmented methylprednisolone and donor seropositivity. However, in multivariate analyses, elevated virus load continued to be the predominant risk factor for progression to HCMV disease.

Cholesterol reduction by glucomannan and chitosan is mediated by changes in cholesterol absorption and bile acid and fat excretion in rats

Glucomannan, a viscous polysaccharide, and chitosan, a derivative of chitin, have both been demonstrated to lower cholesterol in animals. However, the mechanism of cholesterol lowering has not been established for either material. This study was conducted to determine the effect of glucomannan (G), chitosan (CH), or an equal mixture of the two (G + CH) on cholesterol absorption and fat and bile acid excretion. Rats were fed a modified AIN-93G diet for 18 d containing 0.125 g/100 g cholesterol and initially 10 g/100 g of the test materials or cellulose (C) as the control. However, the concentration of test materials and cellulose was reduced to 7.5 g/100 g after 1 wk due to lower weight gain compared with controls. Total liver cholesterol was significantly reduced in G, CH and G + CH groups compared with the C group. The intestinal contents supernatant viscosity of the C and the CH groups was negligible, whereas both G and G + CH produced high viscosities. Cholesterol absorption, measured by the fecal isotope ratio method, was significantly reduced from 37.5% in the C group to 20.2% in G, 18.2% in G + CH and 9.4% in CH. Daily fecal fat excretion did not differ between the C and G groups, but was significantly greater in G + CH and CH compared with the C and G groups. Daily fecal bile acid excretion was significantly greater in the CH and G + CH groups compared with the C and G groups. These results suggest that G lowered liver cholesterol by a viscosity-mediated interference of cholesterol absorption. In contrast, CH appears to lower cholesterol through a different mechanism.

Dosimetric characteristics of the Pharma Seed model BT-125-I source

125I brachytherapy sources are being used with increasing frequency for interstitial implants in tumor sites, especially the prostate. Recently, a new 125I source design has become commercially available for clinical applications. Dosimetric characteristics (i.e., dose rate constant, radial dose function, and anisotropy function) of this source were experimentally and theoretically determined following the AAPM Task Group 43 (TG-43) recommendations and were related to the 1999 NIST calibration assigned to this source [S(k), 99std]. Measurements were performed in a Solid Water phantom using LiF thermoluminescent dosimeters. The measured data were used to validate the Monte Carlo simulations that were performed in Solid Water using the PTRAN code. The Monte Carlo calculations were then performed in liquid water to obtain the dosimetric information for clinical applications in accordance with TG-43 recommendations. The results indicated that the dose rate constant, lambda, of the Pharma Seed model BT-125-I 125I source was 0.90 +/- 0.06 cGy h(-1) U(-1) using thermoluminescent dosimeter (TLD) measurements and 0.92 +/- 0.03 cGy h(-1) U(-1) using Monte Carlo simulations in Solid Water. The calculated value in liquid water was found to be 0.95 +/- 0.03 cGy h(-1) U(-1). The radial dose function, g(r), of the new 125I source was measured at distances ranging from 0.5 to 10 cm using LiF TLD in Solid Water phantom material. The Monte Carlo simulations were performed for distances ranging from 0.1 to 10 cm from the source center in Solid Water and liquid water. The anisotropy function, F(r, theta), was measured at distances of 2, 5, and 7 cm from the source center and calculated at distances of 0.5, 1, 2, 3, 5, and 7 cm from the source center. The anisotropy constant, phi(an), of the Pharma Seed source in water was found to be 0.975. Complete dosimetric data are described in this manuscript. Per TG-43, the values reported in water should be used for clinical treatment planning systems.

Large-volume liposuction complicated by retroperitoneal hemorrhage: management principles and implications for the quality improvement process

Large-volume liposuction can be associated rarely with major medical complications and death. The case of exsanguinating retroperitoneal hemorrhage that led to cardiopulmonary arrest in an obese 47-year-old woman who underwent large-volume liposuction is described. Extensive liposuction is not a minor procedure. Performance in an ambulatory setting should be monitored carefully, if it is performed at all. Reporting of adverse events associated with outpatient procedures performed by plastic surgeons should be mandated. Hemodynamic instability in the early postoperative period in an otherwise healthy patient may be due to fluid overload, lidocaine toxicity, or to hemorrhagic shock and must be recognized and treated aggressively. Guidelines for the safe practice of large-volume liposuction need to be established.

The human leukocyte antigen HLA DRB3*020/DQA1*0501 haplotype is associated with Graves' disease in African Americans

Information on genetic susceptibility to Graves' disease in African Americans is limited. We studied DRB1, DQB1, DRB3 subtypes, DQA1*0501, DQA1*0201, and CTLA-4 polymorphisms in 49 African American patients with adult onset Graves' disease and 47 racially-matched controls using PCR-based sequence-specific priming methods. There were no significant differences in DRB1 or DQB1 allelic frequencies or CTLA-4 polymorphisms between patients and controls. However, we found that the frequency of DRB3 was significantly increased in the patients (75.5% vs. 57.4%, P = 0.006, X2 = 3.52), especially for the DRB3*0202 subtype (53.1% vs. 23.4, P = 0.003, X2 = 8.91). In this one respect, the finding was in concordance with our previous observations in Caucasian patients with adult-onset Graves' disease. In addition, whereas the frequency of DQA1*0501 was increased (P = 0.018, X2 = 5.63) in our patients, the haplotype of DRB3/DQA1*0501, or DRB3*0202/DQA1*0501 was found to be more strongly associated (P = 0.008, X2 = 7.0; P = 0.0008, X2 = 11.34, respectively). These data suggest that DRB3*0202, particularly when found with DQA1*0501 in a haplotype is a susceptible gene(s) for Graves' disease in adult African Americans. Considering these data with those in Caucasian patients, our results would suggest that the primary Graves susceptible locus is likely DRB3 and not DRB1.

Development and clinical evaluation of a recombinant-antigen-based cytomegalovirus immunoglobulin M automated immunoassay using the Abbott AxSYM analyzer

A new microparticle enzyme immunoassay (MEIA), the Cytomegalovirus (CMV) Immunoglobulin M (IgM) test, was developed on the Abbott AxSYM analyzer. This test uses recombinant CMV antigens derived from portions of four structural and nonstructural proteins of CMV: pUL32 (pp150), pUL44 (pp52), pUL83 (pp65), and pUL80a (pp38). A total of 1, 608 specimens from random volunteer blood donors (n = 300), pregnant women (n = 1,118), transplant recipients (n = 6), and patients with various clinical conditions and disease states (n = 184) were tested during development and evaluation of this new assay. In a preliminary clinical evaluation we tested specimens collected prospectively from pregnant women (n = 799) and selected CMV IgM-positive archived specimens from pregnant women (n = 39). The results from the new CMV IgM immunoassay were compared to the results of a consensus interpretation of the results obtained with three commercial CMV IgM immunoassays. The results for specimens with discordant results were resolved by a CMV IgM immunoblot assay. The relative sensitivity, specificity, and agreement for the AxSYM CMV IgM assay were 94.29, 96.28, and 96.19%, respectively, and the resolved sensitivity, specificity, and agreement were 95.83, 97.47, and 97.37%, respectively. We also tested serial specimens from women who experienced seroconversion or a recent CMV infection during gestation (n = 17) and potentially cross-reactive specimens negative for CMV IgM antibody by the consensus tests (n = 184). The AxSYM CMV IgM assay was very sensitive for the detection of CMV IgM during primary CMV infection, as shown by the detection of CMV IgM at the same time as or just prior to the detection of CMV IgG. Specimens from individuals with lupus (n = 16) or parvovirus B19 infection (n = 6) or specimens containing hyper IgM (n = 9), hyper IgG (n = 8), or rheumatoid factor (n = 55) did not cross-react with the AxSYM assay. One specimen each from individuals infected with Epstein-Barr virus (n = 26), measles virus (n = 10), herpes simplex virus (n = 12), or varicella-zoster virus (n = 13) infection, one specimen from an influenza vaccinee (n = 14), and one specimen containing antinuclear antibody cross-reacted with the assay. The overall rate of cross-reactivity of the specimens with the assay was 3.3% (6 of 184). The AxSYM CMV IgM assay is a sensitive and specific assay for the detection of CMV-specific IgM.

Erratum: Does aluminum exposure of pregnant animals lead to accumulation in mothers of their offspring?

Borak J, Wise JP. 1998. Does aluminum exposure of pregnant animals lead to accumulation in mothers of their offspring? Teratology 57:127-139 In response to the article referenced above, Drs. M. Golub and J. Domingo wrote a Letter to the Editor (Teratology 1998;58:225). Included in that letter was the following statement: "We also urge Drs. Borak and Wise to fulfill their ethical obligation to acknowledge sources of support when submitting manuscripts for publication." This comment would not have been necessary if the article by Borak and Wise had included an acknowledgment of their outside support in their article. The authors had disclosed this outside support in the cover letter to the editor when the manuscript was supplied initially and later after revisions. They did not include an Acknowledgment section in the manuscript. The editorial office should have suggested that they do that. We apologize for any confusion this caused.