A self-resetting spiking phase-change neuron

Neuromorphic, or brain-inspired, computing applications of phase-change devices have to date concentrated primarily on the implementation of phase-change synapses. However, the so-called accumulation mode of operation inherent in phase-change materials and devices can also be used to mimic the integrative properties of a biological neuron. Here we demonstrate, using physical modelling of nanoscale devices and SPICE modelling of associated circuits, that a single phase-change memory cell integrated into a comparator type circuit can deliver a basic hardware mimic of an integrate-and-fire spiking neuron with self-resetting capabilities. Such phase-change neurons, in combination with phase-change synapses, can potentially open a new route for the realisation of all-phase-change neuromorphic computing.

Whole-abdomen, single-dose consolidation radiotherapy in patients with pathologically confirmed complete remission of advanced ovarian epithelial carcinoma: a long-term survival analysis

The value of consolidation therapy in advanced epithelial ovarian carcinoma patients is controversial. The aim of the present study was to assess the long-term survival of patients with a pathologically confirmed complete remission who had consolidation by single-dose, whole-abdominopelvic radiotherapy. Of 96 histologically confirmed stage II-IV epithelial ovarian carcinoma patients who underwent cytoreductive surgery followed by high-dose, platin-based chemotherapy, 57 were in complete clinical remission at the end of therapy and 50 underwent a second-look laparotomy. The study group comprises 32 consecutive patients who had no pathological evidence of disease and who received 800 cGy single-dose, whole-abdominal radiotherapy by an 8 MEV linear accelerator in a single fraction. The absolute 5-year survival and the actuarial 10-year survival were 78.7 and 63.3%, respectively. The survival was significantly better in patients who had < or =2 cm residual disease at the completion of the original operation. No severe postradiation complications were encountered. Mild complications were seen in three (9.4%) patients. Our data indicate a favorable long-term survival of patients with a negative second-look laparotomy who had consolidation with single-dose, whole-abdominal radiotherapy. These results seem to suggest that a collaborative, prospective, randomized multiarm study is indicated to solve the controversial issue of consolidation therapy.

Whole-abdomen, single-dose consolidation radiotherapy in patients with pathologically confirmed complete remission of advanced ovarian epithelial carcinoma: a long-term survival analysis

The value of consolidation therapy in advanced epithelial ovarian carcinoma patients is controversial. The aim of the present study was to assess the long-term survival of patients with a pathologically confirmed complete remission who had consolidation by single-dose, whole-abdominopelvic radiotherapy. Of 96 histologically confirmed stage II–IV epithelial ovarian carcinoma patients who underwent cytoreductive surgery followed by high-dose, platin-based chemotherapy, 57 were in complete clinical remission at the end of therapy and 50 underwent a second-look laparotomy. The study group comprises 32 consecutive patients who had no pathological evidence of disease and who received 800 cGy single-dose, whole-abdominal radiotherapy by an 8 MEV linear accelerator in a single fraction. The absolute 5-year survival and the actuarial 10-year survival were 78.7 and 63.3%, respectively. The survival was significantly better in patients who had ≤2 cm residual disease at the completion of the original operation. No severe postradiation complications were encountered. Mild complications were seen in three (9.4%) patients. Our data indicate a favorable long-term survival of patients with a negative second-look laparotomy who had consolidation with single-dose, whole-abdominal radiotherapy. These results seem to suggest that a collaborative, prospective, randomized multiarm study is indicated to solve the controversial issue of consolidation therapy.

Targeting pulmonary metastases of renal cell carcinoma by inhalation of interleukin-2

INTRODUCTION

Pulmonary metastases of renal cell carcinoma (RCC) are associated with poor prognosis. Inhalation therapy with interleukin-2 (IL-2) is thus an appealing method for palliation. This multicenter study summarizes the national experience of IL-2 inhalation in patients with lung metastases of RCC.

PATIENTS AND METHODS

Forty patients (median, 66.5 years of age) with radiologically documented progressing pulmonary metastases were enrolled. All patients had to be able to comply with inhalation technique, and were not candidates for other treatment options. Twenty-eight patients were systemic treatment-naïve. The protocol included three daily inhalations of IL-2 to a total dose of 18 MU. Treatment had to be continued until one of the following occurred: progression; a complete response; a life threatening toxicity; or patient refusal. Response was assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) system.

RESULTS

The disease-control rate reached 57.5%, with a partial response rate of 2.5% and a disease stabilization rate of 55%. Median time to progression was 8.7 months. The main side-effects were cough and weakness.

CONCLUSIONS

Inhalation of IL-2 for the treatment of pulmonary metastases in RCC is feasible, tolerable and beneficial in controlling progressive disease for considerable periods of time. The definition of response of biological therapy may need to be re-assessed and modified: stable disease should be regarded as a favorable response.

Malignant thymoma invading pulmonary artery. Changing treatment options

BACKGROUND

Curative treatment of malignant thymoma is resection; however, this may be precluded by invasion of vital organs.

PATIENTS AND METHODS

Two patients with extensive intrathoracic spread of thymoma (Stages III and IV A) are presented. Treatment involved a combination of resection, radiotherapy and chemotherapy.

RESULTS

One patient survived 9 years, 4 months, but eventually died of metastatic spread; the other one is well and without evidence of disease 30 months after treatment.

CONCLUSIONS

Thymoma is a slow-growing tumor. Successful surgical treatment in advanced cases is possible, if aided by radiotherapy and chemotherapy. The adjuvant therapy converts a non-resectable tumor to a resectable one.

Heat-induced alterations in cell membrane permeability and cell inactivation of transformed mouse fibroblasts

Hyperthermia, has recently been extended in many permutations as a modality of anticancer treatment, but the mechanisms underlying heat-induced cell inactivation are poorly understood. In this study, the role of the cell permeability barrier in the process of heat cytotoxicity are examined. Changes in cell membrane permeability were determined by following the efflux of normally impermeant metabolites, e.g. nucleotides, in cultures of Swiss mouse 3T3 cells, and their transformed derivatives, 3T6 cells. The increase in cell membrane permeability as a function of temperature and exposure duration was found to be characterized by a sigmoid curve, with a threshold value, above which the permeability markedly increased. A correlation was found between cell membrane permeabilization and cell inactivation. Both heat-induced permeabilization and heat cytotoxicity were more pronounced in the transformed cells, as compared to their untransformed counterparts. The temperature-dependent permeabilization was more effective in the presence of the ionophore amphotericin B. The data suggest that heat-induced lesion in the cell membrane has a major role in hyperthermia cytotoxicity.

Prophylactic low-dose post-operative orthovoltage radiotherapy in stage II breast cancer

Between the years 1974 and the beginning of 1977, 199 patients with stage II infiltrating duct carcinoma of the breast were treated with post-operative radiation, using a 250 kVp X-ray machine. Three treatment schedules were used consisting of 22, 26.2 and 29.6 Gy (2200, 2620 and 2960 rad) total tumour dose, calculated at 2 cm depth, with 5, 3 and 3 fractions a week respectively. The frequency of local recurrences, mainly in the chest wall, were 20.3%, 8.3% and 8.1% respectively. The latter two frequencies were not different from those reported for the commonly used high dose treatments of 45-60 Gy (4500-6000 rad) delivered either as given doses or tumour doses. An approximate 70% five year survival rate was similar in the three groups and does not differ from results observed with high doses. Low dose treatment is advantageous, because it has fewer complications and it can be delivered in a smaller number of sessions, making it more convenient to the patient, without loss of efficacy. The results presented of the low dose treatment may reflect the existence of an optimal dose level of radiation.