Limb salvage in soft tissue sarcomas involving neurovascular structures using combined surgical resection and brachytherapy

While there is debate in the literature concerning the tolerance of neurovascular structures to external beam radiation, the tolerance of these tissues to interstitial radiation has never been established. To evaluate the dose of radiation and its effect on early and late toxicity of neurovascular structures, a retrospective review of our experience was undertaken. Between 1975 and 1987, 299 patients with extremity sarcomas underwent limb-sparing surgery and tumor bed Iridium-192 interstitial implantation at Memorial Sloan-Kettering Cancer Center. Forty-five patients (15%) of this group were found to have locally advanced tumors involving major neurovascular structures. Of these patients, 64% had high grade lesions. Eleven percent had evidence of gross residual disease on these structures, and an additional 58% had microscopic residual disease at or close to the margins of resection. After loading catheters were placed directly upon the neurovascular structures in the exposed tumor bed and a median dose of 4400 cGy was delivered to the target volume. Eight patients had previous radiation to the treated field and 13 patients received postoperative radiation. With a median follow-up of 4 years, the 5-year actuarial disease-free survival was 69% and the 5-year actuarial freedom from in-field failure was 79%. The 5-year actuarial incidence of distant metastases was 30%. Eighty-four percent of the patients maintained long-term preservation of limb function without the need for amputation. Four patients (9%) ultimately developed evidence of radiation neuritis 6-20 months post therapy. All four patients had received additional radiation with cumulative doses exceeding 9000 cGy to the neurovascular bundle. We conclude that combined surgical resection and interstitial radiation for locally advanced sarcomas with neurovascular involvement can provide excellent local control with preservation of limb and neurovascular function without significant toxicity.     

Comparison of electroretinographic responses between two different age groups of adult Dark Agouti rats

AIM: To describe and compare the differences in electroretinographic responses between two different age groups of adult Dark Agouti (DA) rats and to better understand the effect of age on retinal histology and function.METHODS: The electroretinographic responses of two different age groups of adult DA rats were compared. Animals were divided into younger adult DA rats 10-12wk (n=8) and older adult DA rats 17-19wk (n=8). Full field electroretinography (ERG) was recorded simultaneously from both eyes after dark adaption and light adaption and parameters including the positive scotopic threshold response (pSTR), negative scotopic threshold response (nSTR), scotopic a-wave, b-wave, photopic a-wave, b-wave and photopic negative response (PhNR) were compared between groups.RESULTS: The older adult rats displayed lower stimulation thresholds of the STRs (pSTR and nSTR) and higher amplitudes of pSTR, scotopic a-wave and b-wave, photopic b-wave and PhNR amplitudes, with shorter implicit times. Photopic a-wave amplitudes were however higher in the younger adult rats.CONCLUSION:In summary, for the rod system, photoreceptor, bipolar cell and RGC activity was enhanced in the older adult rats. For the cone system, RGC and bipolar cell activity was enhanced, while photoreceptor activity was depressed in the older adult rats. Such age-related selective modification of retinal cell function needs to be considered when conducting ophthalmic research in adult rats.     

En bloc kidney transplantation from infant donors younger than 10 months into pediatric recipients

Early graft loss and poor graft function limit the use of kidneys from infant donors. Six en bloc kidney transplantations were performed from infant donors younger than 10 months into pediatric recipients between November 2012 and September 2015 at our center. We retrospectively analyzed recipient and donor demographics, surgery procedures, complications, graft function and size, and patient and graft survival with a follow‐up of 6‐39 months (median 15.5 months). Donor age ranged from 1 to 10 months with weight ranging from 3.5 to 10 kg. Recipient age ranged from 10 to 16 years with weight ranging from 30 to 39 kg. One kidney was removed due to arterial thrombosis during surgery, while the other kidney of this en bloc graft remained viable. Urine leak followed by bilateral ureteral obstruction occurred in one recipient. All of the recipients showed immediate graft function. The size of the en bloc kidney increased from 4.2±0.6 cm to 7.6±0.6 cm 6 months after surgery. Patient and graft survival were both 100% at the last follow‐up. Our results show that en bloc kidney transplantation from infant donors younger than 10 months into pediatric recipients is effective under the condition of experienced surgical techniques and perioperative management.     

Malignant peripheral nerve sheath tumors of the buttock and lower extremity. A study of 43 cases

Using strict clinical and pathologic criteria for the inclusion of cases, the authors have reviewed the clinicopathologic features of 43 malignant peripheral nerve sheath tumors of the buttock and extremity seen over a 35-year period. Twenty-three (53%) of the patients had neurofibromatosis (VRN), whereas 20 (47%) did not. Fifty-one percent of the patients were women. The mean age at presentation was 36 years for patients with VRN and 44 years for patients without VRN. A nerve of origin was identified for 72% of the cases and an associated neurofibroma for 44% (65% with VRN and 20% without VRN). The mean greatest dimension of the tumors was 12.3 cm, and this did not differ significantly between the two groups. The predominant histologic pattern in 86% of the tumors was that of tightly packed spindle cells in an interlacing and woven pattern; heterologous sarcomatous elements were noticed in 12% of the cases. Surgical resection was the main modality of treatment for all patients; 65% also received adjuvant therapy. Follow-up evaluation was done in every case. An unexpected finding was the absence of a significant difference in survival rates between patients with and without VRN. Overall, 63% of the patients died of tumor: 65% of the patients with VRN and 60% of the patients without VRN. Large tumor size and high mitotic rate (greater than 20 per 10 high-power fields) portended a poor prognosis, as did the need for resection by amputation. Adjuvant radiation therapy and chemotherapy did not affect survival rates.     

Lymphopenia and deranged lymphocyte subsets in nasopharyngeal carcinoma

The peripheral blood lymphocyte counts of 333 patients with a nasopharyngeal carcinoma and 125 control subjects were compared. The mean pretreatment lymphocyte count in the patients was significantly lower than that of the normal controls (P less than 0.0001). Subgroup analysis of absolute lymphocyte counts in different stages of the disease revealed a stage dependent lymphopenia which became significant when the disease was stage III or over (P less than 0.001). Characterization of peripheral blood lymphocyte subsets in 81 patients and 46 normal control subjects revealed a significant reduction of the absolute Pan T (T11) lymphocytes in the patients (P less than 0.0001). Both the absolute numbers of T helper (T4) and suppressor cells (T8) were reduced in the patients (P less than 0.0001 and less than 0.026, respectively). While the percentage of T4 was reduced (P less than 0.0001), the percentage of T8 was elevated (P less than 0.02), resulting in a reduced T4/T8 ratio (P less than 0.0001). The mean absolute and percentage counts of T11, T8 and B did not correlate with different stages of the disease.     

A new parameter tuning approach for enhanced motor imagery EEG signal classification

A brain-computer interface (BCI) system allows direct communication between the brain and the external world. Common spatial pattern (CSP) has been used effectively for feature extraction of data used in BCI systems. However, many studies show that the performance of a BCI system using CSP largely depends on the filter parameters. The filter parameters that yield most discriminating information vary from subject to subject and manually tuning of the filter parameters is a difficult and time-consuming exercise. In this paper, we propose a new automated filter tuning approach for motor imagery electroencephalography (EEG) signal classification, which automatically and flexibly finds the filter parameters for optimal performance. We have evaluated the performance of our proposed method on two public benchmark datasets. Compared to the existing conventional CSP approach, our method reduces the average classification error rate by 2.89% and 3.61% for BCI Competition III dataset IVa and BCI Competition IV dataset I, respectively. Moreover, our proposed approach also achieved lowest average classification error rate compared to state-of-the-art methods studied in this paper. Thus, our proposed method can be potentially used for developing improved BCI systems, which can assist people with disabilities to recover their environmental control. It can also be used for enhanced disease recognition such as epileptic seizure detection using EEG signals.

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An objective computer system for the quantification of artery stenoses

Summary We have developed a low cost, clinically usable system for the objective assessment of the severity of coronary artery stenoses from single view angiograms. The system is based on a desktop computer with incorporated frame grabber. Images are captured by means of a video camera.The user selects a region of interest which encompasses the stenosis. Facilities are provided for automatic or manual definition of the artery centre line and edges. The computer then calculates the artery diameter and cross-sectional area by videodensitometry along profile lines which are orthogonal to the long axis of the artery. These results can be expressed numerically as a percentage stenosis when compared to a normal region of the artery.The image is corrected for geometric distortion using a grid test object. The image grey scale is corrected by means of a ramp test object such that a pixel value is proportional to the attenuator thickness. The ramp is placed on the patient during the X-ray examination and an iterative technique has been developed for subtracting the underlying structures from the superimposed ramp image. The system has been assessed using test objects constructed in Perspex which simulate arteries of known cross-sectional area and stenoses of known severity.