Biomedical subjects
Publications and source records attributed to R Kuske.
A multiscale approach is used to derive stochastic amplitude and phase dynamics for a canonical noise-sensitive model exhibiting coherence resonance. Explicit expressions for the dependence on noise levels and model type are compared with computational coherence measures.
Breast conserving surgery followed by radiation therapy has been accepted as an alternative to mastectomy in the management of patients with early-stage breast cancer. Over the past decade there has been increasing interest in a variety of radiation techniques designed to treat only the portion of the breast deemed to be at high risk for local recurrence (partial-breast irradiation [PBI]) and to shorten the duration of treatment (accelerated partial-breast irradiation [APBI]). To consider issues regarding the equivalency of the various radiation therapy approaches and to address future needs for research, quality assurance, and training, the National Cancer Institute, Division of Cancer Treatment and Diagnosis, Radiation Research Program, hosted a Workshop on PBI in December 2002. Although 5- to 7-year outcome data on patients treated with PBI and APBI are now becoming available, many issues remain unresolved, including clinical and pathologic selection criteria, radiation dose and fractionation and how they relate to the standard fractionation for whole breast irradiation, appropriate target volume, local control within the untreated ipsilateral breast tissue, and overall survival. This Workshop report defines the issues in relation to PBI and APBI, recommends parameters for consideration in clinical trials and for reporting of results, serves to enhance dialogue among the advocates of the various radiation techniques, and emphasizes the importance of education and training in regard to results of PBI and APBI as they become emerging clinical treatments.
A combination of asymptotic approaches provides a new analysis of the effect of small noise on the bursting cycle of a neuronal burster of elliptic type (type III). The analysis is applied to a stochastic model of an excitable spine, with an activity-dependent stem conductance, that exhibits conditional burst dynamics. First, we give an asymptotic approximation to the probability density for the state of the system. This density is used to compute several quantities which describe the influence of the noise on the transition from the silent to the active phase. Second, we also use a multiscale method to provide a reduced system for analysing the effect of noise on the transition out of the active phase. The combination of these two approaches results in a new framework for a quantitative description of how noise shortens the burst cycle, which measures the significant influence of small noise. For the stochastic spine model, this study suggests that small amplitude noise can significantly influence the activity-dependent morphological plasticity of dendritic spines. The techniques used in this paper combine probabilistic and asymptotic methods, and have been generalized for other noisy nonlinear systems.
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PURPOSE: To determine the 15-year outcome for women with ductal carcinoma in situ (DCIS, intraductal carcinoma) of the breast treated with breast-conserving surgery followed by definitive breast irradiation. PATIENTS AND METHODS: An analysis was performed of 270 intraductal breast carcinomas in 268 women from 10 institutions in Europe and the United States. In all patients, breast-conserving surgery included complete gross excision of the primary tumor followed by definitive breast irradiation. When performed, pathologic axillary lymph node staging was node-negative (n=86). The median follow-up time was 10.3 years (range, 0.9 to 26.8). RESULTS: The 15-year actuarial overall survival rate was 87%, and the 15-year actuarial cause-specific survival rate was 96%. The 15-year actuarial rate of freedom from distant metastases was 96%. There were 45 local recurrences in the treated breast, and the 15-year actuarial rate of local failure was 19%. The median time to local failure was 5.2 years (range, 1.4 to 16.8). A number of clinical and pathologic parameters were evaluated for correlation with local failure, and none were predictive for local failure (all P > or = .15). CONCLUSION: The results from the present study demonstrate high rates of overall survival, cause-specific survival, and freedom from distant metastases following the treatment of DCIS of the breast using breast-conserving surgery and definitive breast irradiation. These results support the use of breast-conserving surgery and definitive breast irradiation for the treatment of DCIS of the breast.
PURPOSE: The purpose of the present study is to evaluate the outcome of salvage treatment for local recurrence in the breast following the initial treatment of ductal carcinoma in situ (intraductal carcinoma) with breast-conserving surgery and definitive breast irradiation. METHODS AND MATERIALS: An analysis was performed of 42 local failures in the breast that occurred following the initial treatment of ductal carcinoma in situ (intraductal carcinoma) with breast-conserving surgery and definitive breast irradiation. At the time of the local recurrence, 23 cases (55%) showed invasive ductal carcinoma, and 19 cases (45%) showed intraductal carcinoma, one with associated Paget's disease. The surgical treatment at the time of local recurrence included mastectomy (n = 39), excision (n = 2), or other (n = 1). Adjuvant systemic therapy at the time of local recurrence included chemotherapy (n = 2), hormonal treatment (n = 7), both (n = 1), or none (n = 32). The median follow-up after salvage treatment was 3.7 years (mean = 4.0 years; range = 0.1-9.5 years). RESULTS: The 5-year actuarial outcome following salvage treatment for the 42 local recurrences showed an overall survival rate of 78% and a cause-specific survival rate of 84%. The 5-year actuarial rate of freedom from distant metastases was 86%. None of the patients with histology of the local recurrence of intraductal carcinoma or with detection of the local recurrence with mammographic findings only developed distant metastatic disease after salvage treatment. The 5-year actuarial rate of freedom from chest wall recurrence following salvage mastectomy was 92%. All three of the patients who developed chest wall recurrence following salvage mastectomy also developed distant metastatic disease. CONCLUSIONS: These results demonstrate that local recurrences following the initial treatment of ductal carcinoma in situ with breast-conserving surgery and definitive breast irradiation can be salvaged with high rates of survival, freedom from distant metastases, and freedom from chest wall recurrence. The results of salvage treatment support the use of breast-conserving surgery and definitive breast irradiation for the initial management of ductal carcinoma in situ of the breast.
BACKGROUND: To evaluate the pathologic characteristics of the primary tumor relative to local control, survival, and freedom from distant metastases, an analysis was performed of 172 patients with ductal carcinoma in situ (intraductal carcinoma) of the breast treated with breast-conserving surgery and definitive breast irradiation. METHODS: The clinical records and pathology slides were reviewed from 172 women with ductal carcinoma in situ treated with breast-conserving surgery and definitive breast irradiation at multiple institutions in Europe and the United States. Central pathology review was performed by one pathologist without knowledge of the clinical outcome. The clinical outcome was measured in terms of local control, overall survival, cause-specific survival, and freedom from distant metastases. The median follow-up time was 84 months (range, 17-177 months). RESULTS: The pathologic parameters evaluated were histologic subtype, nuclear grade, amount of necrosis, and final pathology margin. The only pathologic parameter that correlated with the rate of local recurrence was the presence versus the absence of the combination of the histologic subtype of comedo carcinoma plus nuclear grade 3 (8-year actuarial rate of local recurrence of 20% versus 5%, respectively; P = 0.009 on univariate analysis; P = 0.017 on multivariate analysis). None of the pathologic parameters evaluated correlated with overall survival (all P > or = 0.16), cause-specific survival (all P > or = 0.13), or freedom from distant metastases (all P > or = 0.13). CONCLUSIONS: These results have demonstrated that there are important differences in the rate of local recurrence based on the pathologic characteristics of the primary tumor for women with ductal carcinoma in situ treated with breast-conserving surgery and definitive irradiation. However, the differences in local recurrence have not been associated with differences in survival or freedom from distant metastases. Careful follow-up for patients at increased risk for local recurrence is warranted because of the potential ability to salvage patients with local recurrence.
An analysis of 259 women with 261 treated breasts from nine institutions in Europe and the United States was performed to determine the 10-year results of the treatment of intraductal carcinoma of the breast with definitive irradiation. All patients had undergone complete gross excision of the primary intraductal carcinoma, and definitive breast irradiation was delivered in all cases. The median follow-up time was 78 months (range, 11 to 197 months). The 10-year actuarial overall survival rate was 94%, and the 10-year actuarial cause-specific survival rate (including deaths only from carcinoma of the breast) was 97%. The 10-year actuarial rate of freedom from distant metastases was 96%. There were 28 failures in the breast, and the 10-year actuarial rate of local failure was 16%. The pathologic type of local recurrences showed invasive ductal carcinoma in 14 of 28 recurrences (50%) and noninvasive ductal carcinoma in 14 of 28 recurrences (50%). The median time to local failure was 50 months (range, 17 to 129 months). Twenty-four of 28 patients with local failure were salvaged with additional treatment, generally mastectomy, and 4 of 28 patients with local failure subsequently had distant metastases. Median follow-up time after salvage treatment of breast recurrence was 29 months (range, 3 to 90 months). Two patients without local failure subsequently had distant metastases, one of which occurred after a node-positive, contralateral breast carcinoma. These results demonstrate high rates of overall survival, cause-specific survival, and freedom from distant metastases for the treatment of patients with intraductal carcinoma of the breast. The local recurrences within the treated breast were generally salvaged with additional treatment, although with limited follow-up. Because of the long natural history of intraductal carcinoma of the breast, prolonged and careful follow-up of patients after breast-conservation and definitive irradiation is required.
Three-dimensional treatment planning for the intact breast was performed on two patients who had undergone CT scanning. A total of 38 treatment plans were evaluated. Multiple plans were evaluated for each patient including plans with and without inhomogeneity corrections, plans using varying photon energies of 60Co, 4 MV, 6 MV, 10 MV, and 15 MV, and three-dimensionally unconstrained plans. Increased hot spots were appreciated in the central axis plane when lung inhomogeneity corrections were used. Additional hot spots were appreciated in off-axis planes towards the cephalad and caudad aspects of the target volume because of lung inhomogeneity corrections and changes in the breast contour. The use of 60Co was associated with an increase in the magnitude and volume of hot spots, whereas the use of higher energy photons such as 10 MV and 15 MV was associated with an unacceptable target coverage at shallow depths. Therefore, for the two patients studied, the use of a medium energy photon beam (such as from a 6 MV linear accelerator) appeared to be the energy of choice for treatment of the intact breast. The three-dimensionally unconstrained plans were able to improve slightly upon the standard plans, particularly with relationship of dose to normal tissue structures. Areas for future research were identified, including the use of tissue compensators.
A 3-fold higher concentration of "endogenous digitalis" is found in the serum of patients with essential hypertension than in the serum of normotensives, whose concentration was determined in 22 normotensive probands by an receptor assay using isolated (Na+ + K+)-ATPase as 76.3 +/- 9.3 nM ouabain equivalents. Since the concentration of "endogenous digitalis" was 7-19 fold higher in 2 patients, who had become uremic due to a malignant hypertension and since their serum levels fell 3-fold by hemodialysis, the hemofiltrate was used for partial purification of the substance. This was possible by hydrophobic chromatography on Amberlite XAD-2, octadecyl-coated silica gel, anion exchange chromatography and affinity chromatography on membrane-bound (Na+ + K+)-ATPase. The partially purified substance behaved like the material described by Cloix et al. (1985) Biochem. Biophys. Res. Commun. 131:1234-1240 and competed with digoxin for digoxin antibodies. Ascorbic acid isolated on the search for an inhibitor of (Na+ + K+)-ATPase from beef brain inhibited [3H]ouabain binding due to a decrease of the ouabain binding sites by a reduction of a group within the ATP binding site of the enzyme. Unsaturated fatty acids claimed to be "endogenous digitalis (Tamura et al. [1985] J. Biol. Chem. 260:9672-9677)" also lowered the capacity of the cardiac glycoside binding site but did not compete with ouabain.
The influence of serum from patients with essential hypertension on the sodium efflux rate constants of human lymphocytes and on the activity of isolated (Na+ + K+)-ATPase was investigated. The ouabain-sensitive sodium efflux rate constant was significantly decreased (p less than 0.001) in the sera of 19 hypertensives (1.92 +/- 0.11 h-1) compared with the sera of 30 normotensives (2.44 +/- 0.07 h-1). The ouabain-insensitive sodium efflux was unaffected. These results corresponded with a significant difference (p less than 0.005) of (Na+ + K+)-ATPase activity (1.03 +/- 0.04 mU/ml and 0.079 +/- 0.06 mU/ml), when an isolated (Na+ + K+)-ATPase was incubated with the sera of 22 normotensives or 18 hypertensives. Both the rate constant of ouabain-sensitive sodium efflux and the (Na+ + K+)-ATPase activity correlated significantly with the diastolic and systolic blood pressure (p less than 0.001). These data, therefore, demonstrated the close relationship between essential hypertension and the concentration of a circulating inhibitor of the sodium pump.
Abortion was performed by curettage on 71 women with pregnancies between the 7th and the 13th week of gestation seven to eight hours after intracervical application of a tylose gel containing 3mg prostaglandin F2 alpha. Prior to the application of the prostaglandin and immediately before the surgical intervention a sonographic examination for determining the vitality of the pregnancy was carried out.--Plasma progesteron, estradiol and HPL levels were determined radioimmunologically prior to the application of prostaglandin, at four-hour intervals on the day of intervention, and 24, 48 and 72 hours after the intervention. In 22 women a complete or an incomplete abortion occurred; in two cases a blighted ovum was observed; 47 pregnancies, according to sonographic examination, remained intact until curettage. After seven to eight hours duration of the effect of the prostaglandin gel, progesterone levels were found to be reduced to 60.5 per cent and 17-beta-estradiol to 31.4 per cent of the initial values, whereas the HPL values fell below the specificity of the testing procedure (12.5 ng/ml). Comparative investigations of the pregnancies which, according to sonographic findings, remained intact until curettage and those which were aborted after the application of prostaglandin did not, in spite of low plasma progesterone and estradiol levels in the abortive group, reveal any statistically significant differences. The abortive effect--even with local application--of the prostaglandins was confirmed. Conclusions regarding the effective mechanism of the prostaglandins upon the fetoplacental unit and the function of the corpus luteum remain subject to speculation.