Biomedical subjects
Publications and source records attributed to D Weber.
Seven patients who sustained complex distal femoral fractures above total knee arthroplasties all treated by supracondylar (retrograde) femoral nailing were retrospectively evaluated. All the patients demonstrated uncomplicated postoperative follow-ups and returned to weight bearing between 2 and 3 months after surgery. No delayed healing occurred and alignment of the femur was satisfactory.
N-Nitroso-N-methylurea (NMU) is a highly potent direct-acting carcinogen that has been shown to induce cancer in a number of animal species. Although previous research has indicated that nitrosation of creatinine (CRN), a common constituent of meats, dried fish, and seafoods, can form traces of NMU, there is uncertainty as to (1) the yield of NMU and (2) whether detectable amounts of NMU can be formed from cured meats following nitrosation under acidic conditions given the low residual levels of nitrite found in cured meats at the present time. Lack of sensitive and specific analytical methods most likely has hindered progress in research in these areas. An HPLC postcolumn denitrosation-thermal energy analyzer technique and a GC-MS confirmation technique were developed for the determination of NMU in cured meats. Both techniques are highly sensitive (0.5 and 0.03 ppb, respectively) and specific. The optimum pH for NMU formation from CRN ranged between pH 1 and pH 3, and the yields of NMU under variable reactant concentrations ranged between 0.00004 and 0.0046%. When 27 samples of various cured meats (10 g aliquots each) were acidified with HCl (final pH values of 0.8-2.5) and incubated at room temperature for 2 h, without any additional nitrite, 24 gave results below detectable levels but 3 formed 2-26 ng of NMU/10 g of meat. Incubation of the negative meats with additional nitrite (50-500 microg/g of meat) formed 0.6-176 ng of NMU/10 g of sample. Although the amounts of NMU formed were extremely small, this seems to be the first reported formation of NMU from cured meats with and without additional nitrite.
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Among all imaging modalities, magnetic resonance imaging provides the most useful information about the accurate staging of solitary bone plasmacytoma, the prediction of progression of asymptomatic multiple myeloma and the prognosis of symptomatic multiple myeloma. Furthermore, magnetic resonance imaging contributes to the differential diagnosis of compression fractures in patients with myeloma and can be used for assessment of response to treatment.
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The acyclic tetraphenolic derivative 2, 2'-methylenebis[6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphe nol] reacts with excess triethylamine in acetonitrile to form a molecular complex, i.e. triethylammonium 2-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-6-[3-(3-tert-butyl-2-hydrox y-5-methylbenzyl)-2-hydroxy-5-methylbenzyl]-4-methylphenolate acetonitrile solvate, C(6)H(16)N(+).C(39)H(47)O(4)(-).C(2)H(3)N, where the organic HNEt(3)(+) cation is included in the partial cone defined by the aromatic faces of the acyclic polyphenolate.
The professional development of public health leaders requires competency-based instruction to increase their ability to address complex and changing demands for critical services. This article reviews the development of the Leadership Competency Framework by the National Public Health Leadership Development Network and discusses its significance. After reviewing pertinent literature and existing practice-based competency frameworks, network members developed the framework through sequential use of workgroup assignments and nominal group process. The framework is being used by network members to develop and refine program competency lists and content; to compare programs; to develop needs assessments, baseline measures, and performance standards; and to evaluate educational outcomes. It is a working document, to be continually refined and evaluated to ensure its continued relevance to performance in practice. Understanding both the applications and the limits of competency frameworks is important in individual, program, and organizational assessment. Benefits of using defined competencies in designing leadership programs include the integrated and sustained development of leadership capacity and the use of technology for increased access and quality control.
We conducted a phase II study to determine the efficacy and toxicity of 9-cis-retinoic acid (9-cis RA), a pan-retinoid receptor agonist, in the treatment of patients with relapsed and refractory NHL. Patients were eligible if they had histologically documented relapsed or refractory T cell or indolent B cell NHL. The first three patients enrolled received 70 mg/m2 of 9-cis RA orally twice a day, but the remaining patients received a single oral daily dose of 100 mg/m2. After 6 weeks of therapy, tumor response was assessed objectively. Response rate and toxicity were determined in all 29 eligible patients based on an intent-to-treat analysis. Four patients (14%) responded (3 PRs and 1 CR; 95% CI 4%-33%). One patient had a minor response, and eight had stable disease. Responses were observed in two (11%) of 19 patients with B-cell lymphoma and in two (20%) of 10 patients with T-cell lymphoma. The median time-to-treatment failure for the 29 eligible patients was 8 weeks. The most frequent toxic effects were dry skin, headache, hypertriglyceridemia, and hypercalcemia. Five patients discontinued therapy due to toxic side effects, but no toxic deaths occurred during the study. We conclude that 9-cis RA has a modest activity in relapsed and refractory NHL. In this study, responses were observed in patients with B-cell lymphomas and those with T-cell lymphomas.
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PURPOSE: Pulsed dose rate (PDR) treatment is a new approach that associates the physical advantages of high-dose-rate (HDR) technology with the potential radiobiological advantages of low-dose-rate (LDR) brachytherapy. This retrospective study analyzes the feasibility, toxicity, and preliminary oncologic results in a series of 43 patients treated with PDR interstitial brachytherapy. METHODS AND MATERIALS: Twenty-four patients with pelvic, 17 patients with head and neck, and 2 patients with breast cancers were treated. Twenty-eight patients had primary and 15 recurrent tumors; 14 had received prior external irradiation to the same site. The doses per pulse at the prescription isodose were 0.4-1 Gy (median 0.5 Gy), delivered using a single cable-driven 0.3-1.0 Ci 192-iridium source (PDR Nucletron Micro-Selectron). RESULTS: The median treated volumes (at the prescribed isodose) were 28 cc for pelvic, 8.33 cc for head and neck, and 40 cc for breast malignancies. Of 14,499 source and 14,499 dummy source transfer procedures, 3 technical machine failure events were observed (0.02%). Grade 3 acute toxicities were seen in 5/43 patients (4 oral stomatitis, 1 vaginal mucositis) and grade 4 acute toxicity in one patient (rectovaginal fistula). Grade 3-4 late complications were observed in 4/41 (9.8%) patients: 1 pubic fracture, 1 rectovaginal fistula, 1 vesicovaginal fistula and 1 local necrosis. With a median follow-up of 18 months, 10/41 patients progressed locoregionally (6 pelvic, 4 head and neck), 3 developed local recurrence and distant metastasis (3 pelvic), 3 only distant metastasis (2 pelvic, 1 head and neck). Two patients are lost to follow-up. CONCLUSION: PDR interstitial brachytherapy for pelvic, head and neck, and breast malignancies is feasible and the acute and late toxicities seem acceptable. Although the physical advantages of PDR are clear, further follow-up is required to determine how results compare with those obtained with standard LDR brachytherapy.
In seven patients who sustained eight distal femoral fractures following knee arthroplasty all fractures were treated operatively. Seven with open reduction internal fixation and one with external fixation. Seven of eight fractures had an unsatisfactory result. This was due not only to bone quality and fracture comminution, but also to technical problems and choice of implant. Revision surgery is often required.
Several studies have shown an association between high nuclear grade or necrosis of ductal carcinoma in situ (DCIS) lesions and the risk of local disease recurrence in patients with DCIS treated surgically with less than mastectomy. Although criteria for separating low from high nuclear grade lesions have been published, no information exists regarding interobserver reproducibility (IR). To assess IR in the classification of DCIS, six surgical pathologists from four institutions used the Lagios grading system to grade 125 DCIS lesions. Before meeting to evaluate the cases, a training set of 12 glass slides, including cases chosen to present conflicting cues for classification, was mailed to the participants with a written criteria summary. This was followed by a working session in which criteria were reviewed and agreed on. The pathologists then graded the lesions independently. The area of interest was marked on each slide before grading. After initial grading, the pathologists met again to resolve discrepant lesion classifications. A complete agreement among raters was achieved in 43 (35%) cases, with five of six raters agreeing in another 45 (36%) cases. In no case did two raters differ by more than one grade. The pairwise kappa agreement values ranged from fair to substantial (0.30 to 0.61). Generalized kappa value indicated moderate agreement (0.46, standard error = 0.02). Kappa statistics for the distinction between grades 1 and 2 and 2 and 3 were 0.29 and 0.48, respectively, (standard error = 0.02). Only one of the six raters differed significantly in scoring. With adherence to specific criteria, IR in the classification of DCIS cases can be obtained in most cases. Although these pathologists made a few grading system modifications, further refinements are needed, especially if grading will influence future therapy.
BACKGROUND AND PURPOSE: Solitary extramedullary plasmacytoma (EMP) represents a rare category of malignant disease on which there are limited data in regard to diagnosis, staging and natural history. This study attempted to clarify the clinical course of solitary extramedullary plasmacytoma after radiation or surgical therapy given with curative intent. MATERIALS AND METHODS: The diagnosis was based on a mass of clonal plasma cells separate from bone or bone marrow without evidence of occult disease elsewhere. Between 1963 and 1996, 22 previously untreated patients with an EMP were diagnosed. Disease presented in the head or neck in 86%, usually in the nasal cavity (NC) or maxillary sinus (MS), and in these areas local bone destruction was found in 10 of 11 patients. Among all patients, serum myeloma protein was present in three patients (14%) and Bence Jones protein alone was found in two patients (9%). Radiation therapy was the sole treatment for 18 of 22 patients, and the median radiotherapy dose was 50 Gy (range, 40-60 Gy); five of seven patients with an EMP of oral cavity (OC), oropharynx (OP), nasopharynx (NP), parotid or larynx also received elective neck irradiation. Two patients underwent surgery plus postoperative irradiation of a plasmacytoma of the sigmoid colon or pleura, and two patients had resection alone of a plasmacytoma of the colon or cervical lymph node. RESULTS: Local control was achieved in 21 of 22 patients (95%), and disease never recurred in regional nodes. Disappearance of myeloma protein occurred in three of five patients with an evaluable abnormality. Multiple myeloma developed in seven patients (32%), all within 5 years. The 5-year rate of freedom from progression to multiple myeloma was 56% and the median survival was 9.5 years. CONCLUSION: Radiation therapy achieved excellent locoregional control of EMP with an approximate cure fraction of 50%.