Comparison of left anterior oblique, anterior, and geometric mean methods in gastric emptying assessment of postpancreaticoduodenectomy patients

Although left anterior oblique (LAO) gastric emptying studies appear to be an adequate alternative to geometric mean (GM) measurements in patients with normal gastric anatomy, it is not clear whether they can be used after gastric or duodenal surgery. In this study, dual-phase gastric emptying studies with combined solid-liquid meal were performed in 54 patients who had undergone pancreaticoduodenectomy (Whipple procedure). Gastric emptying was studied with GM, LAO, and anterior (ANT) methods. T1/2 and percent gastric retention at 10, 30, 60, 90, and 120 minutes were calculated. Results from the three methods were compared using correlation analysis and the t test. The t test showed no significant difference in T1/2 and percent retention values between the GM and LAO or ANT views. The solid emptying T1/2 showed a better correlation between GM and LAO values (r = 0.824) than between GM and ANT (r = 0.589). For the liquid T1/2, the reverse was true. Correlation between GM and ANT (r = 0.939) was better than between GM and LAO (r = 0.839); however, both LAO and ANT views correlated well with GM liquid emptying. It is concluded that the LAO view can replace GM gastric emptying methods in postpancreaticoduodenectomy patients for evaluation of both solid and liquid emptying, although the ANT view appears completely adequate for the study of liquid emptying.     

Verification of the omni wedge technique

The optimal field shape achieved using a multileaf collimator (MLC) often requires collimator rotation to minimize the adverse effects of the scalloped dose distribution the leaf steps produce. However, treatment machines are designed to deliver wedged fields parallel or perpendicular to the direction of the leaves. An analysis of cases from our clinic showed that for 25% of the wedged fields used to treat brain and lung tumors, the wedge direction and optimal MLC orientation differed by 20 degrees or more. The recently published omni wedge technique provides the capability of producing a wedged field with orientation independent of the orientation of the collimator. This paper presents a comparison of the three-dimensional (3D) dose distributions of the omni wedged field with distributions of wedged fields produced using both the universal and dynamic wedge techniques. All measurements were performed using film dosimetry techniques. The omni wedge generated fields closely matched the conventional wedged fields. Throughout 95% of the irradiated volume (excluding the penubra), the dose distribution of the omni wedged field ranged from +5.5 to -3.5 +/- 1.5% of that of the conventionally wedged fields. Calculation of the omni wedged field is as accurate as conventional wedged field calculation when using a 3D treatment planning systems. For two-dimensional treatment planning systems, where one must assume that the omni wedged field is identical to a conventional field, the calculated field and the delivered field differs by a small amount.     

Radiation-induced enhanced proliferation of human squamous cancer cells in vitro: a release from inhibition by epidermal growth factor

Ionizing radiation is believed to stimulate the repopulation of squamous carcinoma cells that survive the early portion of a fractionated course of radiotherapy. To characterize any intrinsic radiation-induced adaptive response and to examine whether epidermal growth factor (EGF) influences this response, A431 and 183A cells were irradiated with repeated daily exposures of 0.5-0.75 Gy and then grown in monolayer culture for 7 days with or without EGF at a 1 ng/ml concentration. Cell numbers were quantified using a microtiter dye-reduction assay. EGF alone caused approximately 70% and 30% growth inhibition of human SC A431 and 183A cells, respectively. Although radiation alone did not affect proliferative rates in these conditions, radiation eliminated the EGF-related growth inhibition in both cell lines. This effect was dose dependent in single radiation exposure experiments. Cell cycle analyses indicated that EGF initially promoted entry into S-phase 3 days after treatment but caused a G1-S block after 7 days. Treatment with radiation recruited cells into S-phase and G2-M, an effect which was sustained 7 days after treatment, overriding the influence of EGF. Radiation-induced modulation of the response of human squamous carcinoma cells to EGF in vitro after single and repeated radiation exposures suggests a proliferation response that may underlie enhanced repopulation of tumor clonogens in vivo.     

BiP maintains the permeability barrier of the ER membrane by sealing the lumenal end of the translocon pore before and early in translocation

Secretory proteins are cotranslationally translocated across the mammalian ER membrane through an aqueous pore in the translocon while the permeability barrier is maintained by a tight ribosome-membrane junction. The lumenal end of the pore is also blocked early in translocation. Extraction of soluble lumenal proteins from microsomes and reconstitution with purified proteins demonstrate, by fluorescence collisional quenching, that BiP seals the lumenal end of this pore. BiP also seals translocons that are assembled but are not engaged in translocation. These ribosome-free translocons have smaller pores (9-15 A diameter versus 40-60 A in functioning translocons) and are generated when ribosomes dissociate from functioning translocons with large pores. BiP therefore maintains the permeability barrier by sealing both nontranslocating and newly targeted translocons.     

Comparison between enzyme-linked immunosorbent assay and cytotoxic cross-match procedures for detecting IgG anti-donor antibodies

BACKGROUND: Disadvantages inherent to complement-dependent cytotoxicity cross-match (CDC XM) methods are the requirements for complement and viable target cells, detection of antibodies (Abs) against non-HLA antigens, and subjective scoring. Cross-Stat (SangStat Medical Corp., Menlo Park, CA), a recently developed enzyme-linked immunosorbent assay XM procedure for the detection of IgG anti-donor HLA Abs, is theoretically devoid of these flaws. METHODS: We compared results of Cross-Stat and our standard anti-human globulin (AHG)-enhanced CDC XM procedure on 524 sera from 230 transplant candidates, which were evaluated against 51 cadaveric donors. RESULTS: There was a significant correlation between AHG-CDC IgG XM and Cross-Stat results (P<0.001). For false negative sera, repeat AHG-CDC IgG XMs were still positive after platelet absorption, indicating that the Abs present were either non-HLA Abs or anti-HLA class II. Flow cytometry testing of false positive sera usually (42/62) substantiated Cross-Stat results, indicating that the discrepancy with AHG-CDC IgG XM is caused by greater sensitivity of Cross-Stat. Relative to the AHG-CDC XM, the sensitivity of Cross-Stat was 100%, the specificity was 93%, the positive predictive value was 73%, and the negative predictive value was 100%. A technical shortcoming of the Cross-Stat assay is that the frequency of indeterminate samples in the assays was 15%. Among 49 Cross-Stat negative vs. 13 Cross-Stat positive primary cadaveric renal allograft recipients (all AHG-CDC IgG-XM negative), there was no statistical difference in overall graft survival. CONCLUSION: Given the important theoretical advantages of enzyme-linked immunosorbent assay-based XM methods over the CDC XM, however, further testing of the clinical relevance of the Cross-Stat is warranted.     

Synergistic interaction of 3 M KCl-extracted donor antigens (e-HAg) with cyclosporine or cyclosporine/sirolimus for prolongation of rat heart allograft survival

This article examines the attaching and detaching experience of a mother encountering the perinatal death of a twin. Her experience is related to the relevant theoretical and research literature pertaining to prebirth and postbirth maternal-infant attachment and detachment (grieving). Literature for both single infants and twins is considered. The experience of this mother suggests that elements of postbirth attachment may have been accelerated into the prebirth period. In addition, her postbirth attaching and detaching experience suggests that an attachment and detachment to the twins as a unit preceded detachment from the twin who died. The health care provider's role in promoting maternal well-being, and indirectly the well-being of the surviving infant, is described.