Experimental determination of dosimetry functions of Ir-192 sources

Experimental data related to the dosimetric characteristics of Ir-192 brachytherapy sources are limited. The aim of this work was to obtain the dosimetry functions required by the American Association of Physicists in Medicine Task Group 43 for both a low and a high dose-rate iridium-192 brachytherapy source through dose measurements in a water-equivalent phantom. Dose measurements have been performed using lithium fluoride thermoluminescent detectors positioned in a polystyrene phantom at distances from the source that vary from 1 to 10 cm, with 1 cm intervals, and at angles that vary from 0 degree to 170 degrees with 10 degrees intervals. The anisotropy functions, radial dose functions, and dose rate constants were determined for both brachytherapy sources. The precision of results obtained on those relatively fine intervals of angles and distances provides clinics with the possibility to use and interpolate the complete data sets for treatment planning.     

Physiological adaptations in adipose tissue of Brahman vs Angus heifers

Twenty-six specimens of tubular adenoma and 7 specimens of adenocarcinoma in adenoma of the colon were examined to evaluate apoptosis between adenoma and early adenocarcinoma. Cell proliferation and cell death seemed to be balanced in adenoma with mild and moderate atypia, but unbalanced in adenoma with severe atypia and cancer. Apoptosis was considered to be suppressed at cancer in some cases. However, a number of apoptosis increased at cancer in other cases. Necrosis was seen only in cancer areas. The ratio of cells simultaneously stained by anti-Ki-67 antibody (MIB-1) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labeling (TUNEL) tended to be high from adenoma with moderate atypia to cancer, suggesting the unstableness of DNA. It is possible that cancer cells having highly unstable DNA easily underwent apoptosis as well as necrosis, accidentally. The p53 protein was positive only in cancer areas of three cases. One of these three showed decreased apoptosis in a cancer area, but the other two cases showed increased apoptosis. Furthermore, certain numbers of cancer cells were double-stained by p53 immunohistochemistry and TUNEL. These results suggest that the p53 protein may contribute to suppress apoptosis in the last stage of carcinogenesis of the colonic adenocarcinoma, but other factors including extrinsic stimulation may cause apoptosis despite the mutation of p53 protein.     

Long-term outcome after the mustard repair for simple transposition of the great arteries. 28-year follow-up

The effects of feeding different amounts of colostrum or only milk replacer and the effects of Long-R3-IGF-I (administered s.c. or orally; 50 microg/[kg BW x d] for 7 d), and of s.c. injected recombinant bovine GH (rbGH; 1 mg/[kg BW x d] for 7 d) on small intestinal mucosal morphology in newborn calves were studied by histomorphometry. Neonatal calves fed colostrum six times exhibited greater (P < .01) villus circumferences, areas, and heights in total small intestine and especially in the duodenum than calves fed only milk replacer. Furthermore, villus circumferences and areas in total small intestine were greater (P < .05) in calves fed colostrum once than in calves fed no colostrum. Villus size in total small intestine was smaller (P < .05) in rbGH-treated than in control calves; jejunum villus circumferences and heights were especially reduced (P < .05). Crypt depths in ileum were greater (P < .05) in rbGH-treated calves. In conclusion, prolonged colostrum supply significantly enhanced small intestinal villus size in neonatal calves. In contrast, Long-R3-IGF-I had no significant influence on small intestinal morphology, and rbGH in supraphysiological amounts even reduced small intestinal mucosal variables after 1 wk of treatment. The study demonstrated enhanced postnatal development of the gastrointestinal tract by prolonged colostrum feeding, but not by Long-R3-IGF-I or GH.     

Ethnicity and cancer outcomes: behavioral and psychosocial considerations

Cancer has been the subject of thousands of behavioral and psychosocial studies. The literature has focused largely on non-Hispanic Whites, despite the fact that cancer outcomes vary by ethnicity. This article provides a review of those studies that do consider the relations between ethnicity and cancer-related adherence behaviors, survival, and quality of life. The authors propose a mediational framework that links ethnicity and cancer outcomes through socioeconomic status, knowledge and attitudes, and access to medical care. They use this framework to organize the literature and to develop recommendations for future research.     

Effect of FLT3 ligand and granulocyte colony-stimulating factor on expansion and mobilization of facilitating cells and hematopoietic stem cells in mice: kinetics and repopulating potential

We have previously identified a cellular population in murine bone marrow that facilitates engraftment of highly purified hematopoietic stem cells (HSC) across major histocompatibility complex (MHC) barriers without causing graft-versus-host disease. Here we investigated the effect of flt3 ligand (FL) and granulocyte colony-stimulating factor (G-CSF) on the mobilization of facilitating cells (FC) and HSC into peripheral blood (PB). Mice were injected with FL alone (day 1 to 10), G-CSF alone (day 4 to 10), or both in combination. The number of FC (CD8(+)/alpha betaTCR-/gamma deltaTCR-) and HSC (lineage-/Sca-1(+)/c-kit+) was assessed daily by flow cytometry. Lethally irradiated allogeneic mice were reconstituted with PB mononuclear cells (PBMC). FL and G-CSF showed a highly significant synergy on the mobilization of FC and HSC. The peak efficiency for mobilization of FC (21-fold increase) and HSC (200-fold increase) was reached on day 10. Our data further suggest that the proliferation of FC and HSC induced by FL in addition to the mobilizing effect mediated by G-CSF might be responsible for the observed synergy of both growth factors. Finally, the engraftment potential of PBMC mobilized with FL and G-CSF or FL alone was superior to PBMC obtained from animals treated with G-CSF alone. Experiments comparing the engraftment potential of day 7 and day 10 mobilized PBMC indicate that day 10, during which both FC and HSC reached their maximum, might be the ideal time point for the collection of both populations.     

Verification of the correspondence between CT-stimulated and treatment beams

A single phantom technique has been developed to verify the full CT simulation and treatment-beam delivery procedures. The phantom consists of a target delineated by thin copper strips, affixed to therapy verification film, and inserted securely between two slices of water-equivalent material. The target is defined with the aid of the copper strips, and the position of the isocenter and beam parameters such as field size, and gantry and collimator angle are determined by CT simulation. With these parameters, the phantom is subsequently irradiated by the linear accelerator in the treatment position. Correspondence between the planned and the irradiated region is determined by the position of the copper strips on the film. The technique is a simple and practical method for verifying the entire CT simulation and treatment-beam delivery processes, and provides a permanent record of the correspondence between the planning digitally reconstructed radiographs (DRR) and the actual beam delivered.     

Anorectal melanoma--an incurable disease?

PURPOSE: This study was designed to describe recurrence and survival rates after operative treatment for anorectal melanoma and to identify predictive factors for recurrence. METHODS: Records of 50 patients with anorectal melanoma from 1939 to 1993 were reviewed. RESULTS: Overall five-year survival and disease-free survival were 22 and 16 percent, respectively. At the time of diagnosis, 26 percent of patients had metastatic disease, and all died within 12 (mean, 6.3) months. Five-year survival and recurrence rates were identical after either abdominoperineal resection (APR) or wide local excision, both with curative intent. Gender, size of tumor, presence of melanin, positive perirectal lymph nodes, or treatment were not predictive of recurrence. Anorectal melanoma was found incidentally after hemorrhoidectomy or polypectomy in five patients. Three other patients underwent an excisional biopsy of a lesion measuring less than 2 cm. Of these eight patients, five underwent APR and three underwent wide local excision with no microscopic residual tumor at pathology. All developed regional or systemic recurrence at a mean of 21 (range, 4-88) months, and all died of their disease at a mean of 29 (range, 5-98) months. CONCLUSION: Prognosis for anorectal melanoma is poor, irrespective of surgical treatment performed. No predictive factors for recurrence were identified in this series. Wide local excision with a negative margin of a least 1 cm is suggested as the treatment of choice. APR should be reserved for tumor not amenable to local excision or for palliative treatment of large obstructive lesion until effective adjuvant therapies are available.     

Risk factor assessment for the acquisition of fluoroquinolone-resistant isolates of Pseudomonas aeruginosa in a community-based hospital

A case-control study was performed in a community-based nonteaching hospital to assess patient risk factors for the acquisition of fluoroquinolone-resistant isolates of Pseudomonas aeruginosa. Fifty-five patients who were hospitalized between July 1, 1993 and December 31, 1993 and who had P. aeruginosa recovered from a clinical specimen were included in the analysis. Two patient populations were designated based on the fluoroquinolone susceptibility of their P. aeruginosa isolates. Statistical evaluation using univariate analysis of demographic and clinical data from the 42 patients with quinolone-susceptible P. aeruginosa and the 13 patients with quinolone-resistant P. aeruginosa demonstrated that prior receipt of a fluoroquinolone was the only significant risk factor for the subsequent emergence of fluoroquinolone resistance among P. aeruginosa isolated from patients hospitalized in this small community-based institution (p = 0.0196). Multivariate analysis supported the finding that prior receipt of a fluoroquinolone was the major risk factor for the isolation of fluoroquinolone-resistant P. aeruginosa (p = 0.0004); isolation of this Gram-negative bacillus from sputum (p = 0.0306) and a history of recent surgery (p = 0.0058) were also significantly associated as risk factors for resistance.     

Outcome assessment for epilepsy surgery: the impact of measuring health-related quality of life

Epilepsy surgery is an increasingly common treatment for intractable epilepsy; yet there is no clear consensus among experts on how to report epilepsy surgery outcome. Most published outcome reporting systems focus on seizure frequency and type but differ in how they define clinically distinct outcome categories. We used a reliable and valid measure of self-reported health-related quality of life (HRQOL), the Epilepsy Surgery Inventory (ESI)-55, as an external standard by which to evaluate seven previously published, seizure-based outcome classification systems. The ESI-55 was administered to 133 adults who had previously undergone surgery for intractable epilepsy, and results were linked to data on their seizure occurrence before and after surgery (over the year prior to their HRQOL reports). These 133 patients were classified according to each seizure-based outcome system, and variation in HRQOL across outcome groups was evaluated using analysis of variance. Results reveal noteworthy variation in the extent to which different systems reflect patients' HRQOL at follow-up. We modified existing systems to derive a seizure-based surgery outcome system that most closely reflects HRQOL when applied over the latest 1-year postoperative interval.