Biomedical subjects

Nancy Lee

Publications and source records attributed to Nancy Lee.

39 records · Page 3Linked to original sources

PubMed2002

Managing nasopharyngeal carcinoma with intracavitary brachytherapy: one institution's 45-year experience.

PURPOSE: At our institution, we have been using intracavitary brachytherapy as a boost in selected cases of both primary and recurrent nasopharyngeal carcinoma. The local control, distant metastasis-free rate, overall survival, and morbidity are presented. METHODS AND MATERIALS: Between January 1, 1955, and August 2000, 576 patients with a diagnosis of nasopharyngeal carcinoma were seen at the department of radiation oncology, University of California-San Francisco, and 55 patients received intracavitary brachytherapy as one part of their treatment. All patients were treated with megavoltage external beam radiation, including 43 patients treated for initial disease and 12 for recurrence. Brachytherapy was routinely used for early cases of T1 and T2 lesions and selected cases of more advanced lesions, as well as recurrent lesions. The median age was 48 years (range 22-85 years); there were 17 women and 38 men, and 39 patients were ethnic Chinese, 13 were white, and 3 were other races. Stage at treatment (primary and recurrent) was I (n=13), II (n=18), III (n=19), and IV (n=5); 18 patients had concurrent chemotherapy. The brachytherapy applicators used were Rotterdam (n=24), balloon (n=16), ovoid (n=14), and ribbon (n=1). The dose rate was high (n=24), low (n=29), or pulsed (n=2). External beam doses ranged from 54 to 72 Gy for primary disease and 30 to 42 Gy for recurrent disease. Brachytherapy doses ranged from 5 to 7 Gy for high dose rate and 10 to 54 Gy for low dose rate. RESULTS: With a median follow-up of 36 months in those who were treated for primary carcinoma, the 5-year estimate of local control was 89%, the distant metastasis-free rate was 75%, and the overall survival estimate was 86%. Recurrent patients had a median follow-up of 50 months; the 5-year estimate of local control was 64%, the distant metastasis-free rate was 100%, and the overall survival estimate was 91%. Patients with Stage I or II disease had a longer overall survival compared with those with Stage III or IV (p=0.05). There was a significant difference in the rate of distant metastases due to nodal status (N0 vs. N1-N3, p=0.02) or to overall stage (I/II vs. III/IV, p=0.005). CONCLUSIONS: Intracavitary boost brachytherapy was found to be effective and well tolerated in selected cases of both primary and recurrent nasopharyngeal carcinoma.

Adult↗

PubMed2002

ras2 Controls morphogenesis, pheromone response, and pathogenicity in the fungal pathogen Ustilago maydis.

Ustilago maydis, a pathogen of maize, is a useful model for the analysis of mating, pathogenicity, and the morphological transition between budding and filamentous growth in fungi. As in other fungi, these processes are regulated by conserved signaling mechanisms, including the cyclic AMP (cAMP)/protein kinase A (PKA) pathway and at least one mitogen-activated protein kinase (MAP kinase) pathway. A current challenge is to identify additional factors that lie downstream of the cAMP pathway and that influence morphogenesis in U. maydis. In this study, we identified suppressor mutations that restored budding growth to a constitutively filamentous mutant with a defect in the gene encoding a catalytic subunit of PKA. Complementation of one suppressor mutation unexpectedly identified the ras2 gene, which is predicted to encode a member of the well-conserved ras family of small GTP-binding proteins. Deletion of the ras2 gene in haploid cells altered cell morphology, eliminated pathogenicity on maize seedlings, and revealed a role in the production of aerial hyphae during mating. We also used an activated ras2 allele to demonstrate that Ras2 promotes pseudohyphal growth via a MAP kinase cascade involving the MAP kinase kinase Fuz7 and the MAP kinase Ubc3. Overall, our results reveal an additional level of crosstalk between the cAMP signaling pathway and a MAP kinase pathway influenced by Ras2.

Amino Acid Sequence↗

PubMed2001

Molecular correlation for the treatment outcomes in bloodstream infections caused by Escherichia coli and Klebsiella pneumoniae with reduced susceptibility to ceftazidime.

Data are limited on outcomes of treatment with extended-spectrum cephalosporins (ESCs) for infections caused by Enterobacteriaceae that produce extended-spectrum beta-lactamases (ESBLs). This study describes the largest treatment experience of a nonoutbreak series of bloodstream infections caused by strains of Escherichia coli (23 episodes) and Klebsiella pneumoniae (13 episodes) with a ceftazidime minimal inhibitory concentration of > or =2 microg/mL. E. coli isolates produced a greater variety of beta-lactamase types than did K. pneumoniae isolates, among which ESBL production was predominant. Five ESBL types were identified: TEM-12, TEM-71, TEM-6, SHV-12, and SHV-5. Most patients were treated empirically with an ESC-based regimen. A favorable response to treatment with a nonceftazidime ESC was observed when the causative pathogen produced either TEM-6 or TEM-12; ceftazidime treatment was associated with failure of therapy in all patients. Despite the limited clinical success, ESCs are currently not recommended for the treatment of serious infections caused by ESBL-producing strains.

Bacteremia↗