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Biomedical subjects

J M Seddon

Publications and source records attributed to J M Seddon.

At least 127 records · Page 7Linked to original sources
PubMed1986

A clinically useful method for combining gross and microscopic measurements to select high-risk patients after enucleation for ciliochoroidal melanoma.

An objective and reproducible method was devised for estimating the malignant potential of ciliochoroidal melanomas after enucleation. This method requires only a single, routine microslide from which nucleolar area and largest tumor dimension are measured. Previous studies have shown these measurements to be reproducible and highly correlated with mortality. To demonstrate a practical method for clinical application of these measurements, a Cox statistical model was derived from 200 cases supplied by the Armed Forces Institute of Pathology. The resulting model, when applied to 340 cases with known outcome from two independent laboratories, allowed subdivision of patients into groups that suffered a six-fold difference in mortality. These results suggest that a central registry, by applying this method to histologic slides from around the world, could provide information useful for the clinical management of patients enucleated for ciliochoroidal melanoma.

Actuarial Analysis↗
PubMed1986

Prognostic factors for metastasis following proton beam irradiation of uveal melanomas.

Prognostic indicators for the development of metastasis following proton beam irradiation of uveal melanomas were evaluated for 510 patients treated from 1975 to 1984. Thirty-three patients developed metastasis (6.5%) from 3 to 51 months following treatment. The primary site of metastasis was the liver in 28 cases (85%). Both demographic and clinical factors were considered. The three leading predictors of survival without metastasis after proton beam irradiation in order of importance were: (1) largest diameter of the tumor; (2) location of the anterior margin of the tumor; and (3) age at treatment. Worse prognosis was associated with largest tumor diameter greater than 15.0 mm, tumor involvement of the ciliary body and age at treatment older than 59 years.

Adult↗
PubMed1986

Visual outcome after proton beam irradiation of uveal melanoma.

Prognostic factors for visual loss following proton irradiation of uveal melanoma were evaluated for 440 eyes treated from 1975 to 1984, with visual acuity 20/200 or better before treatment. Analysis involved Kaplan-Meier survival curves and Cox proportional hazards analysis with visual outcome defined as worse than 20/200. Prognostic factors were tumor height: rate ratio (ratio of rate of visual loss for one category of the variable relative to the rate of visual loss for a reference category of that variable) of 5.26 (95% confidence interval, 2.66-10.39) for tumors greater than 5 mm compared to tumors 3.0 mm or less in height; distance of tumor from the optic disc and fovea: rate ratio 2.59 (1.63-4.11) for tumors 2DD or less from both the optic disc and fovea compared to those greater than 2 DD from these structures. Also predictive of visual loss were tumor location close to disc only, or close to fovea only, macular detachment, worse pretreatment vision, and higher radiation doses delivered to both the disc and fovea, and lens. Regression analysis using a visual acuity scale gave similar results.

Adolescent↗
PubMed1985

The effects of pre-enucleation irradiation on the development of metastases from intraocular Greene melanoma in hamsters.

Using intraocular Greene melanoma in a hamster model, we studied the effect of pre-enucleation irradiation on the development of melanoma metastases. One group (No. = 111) was treated with 1,210 to 1,600 rads of cobaltous chloride Co 60 gamma irradiation before enucleation and the second group (No. = 100) received no irradiation. The groups did not differ with respect to presence of metastases in the 106 days after tumor implantation (chi 2 = 3.05; P = .08). However, Kaplan-Meier survival curves gave a longer time to melanoma-related death in the irradiated animals compared with the controls (log rank test, P = .0008).

Animals↗
PubMed1985

An investigation into the association between liver damage and metastatic uveal melanoma.

We examined the effect of liver damage induced by carbon tetrachloride on the incidence of hepatic metastasis in the Greene hamster melanoma. Nine of 17 animals with liver damage had melanoma growth in the liver after the intraportal vein injection of tumor cells, whereas tumor growth occurred in four of 27 control animals (P less than .01). These results suggest that, in this model, liver damage predisposes to metastatic involvement by melanoma.

Animals↗
PubMed1985

Comparison of survival rates for patients with uveal melanoma after treatment with proton beam irradiation or enucleation.

UNLABELLED: We compared survival experiences for three groups with uveal melanoma: (1) 120 patients treated by proton beam irradiation from 1975 to 1981; (2) 235 patients treated by enucleation from 1953 to 1973 (enucleation group 1); and (3) 161 patients treated by enucleation from 1975 to 1981 (enucleation group 2). The following variables were predictive of melanoma-related deaths. TREATMENT: rate ratio (ratio of the rate of death for one category of the variable relative to the rate of death for another category) of 6.32 (95% confidence interval 1.70 to 23.51) for enucleation group 1 vs proton beam, 3.06 (0.81 to 11.54) for enucleation group 2 vs proton beam, and 2.07 (1.05 to 4.07) for enucleation group 1 vs enucleation group 2. Size: rate ratio of 3.61 (1.51 to 8.64) for large (16+ mm) vs small (less than 11 mm) tumors. LOCATION: rate ratio of 3.19 (1.56 to 6.53) for tumors anterior vs posterior to the equator. When death from all causes was evaluated as the outcome, the estimated rate ratios were similar. When melanoma metastasis was evaluated as the outcome, the estimated rate ratios were reduced in magnitude.

Adult↗
PubMed1985

Prognostic factor study of survival after enucleation for juxtapapillary melanomas.

We reviewed 242 cases of choroidal and ciliary body melanoma that were treated by enucleation to determine the importance of juxtapapillary location as a prognostic factor for tumor-related deaths. Analysis involved Kaplan-Meier survival curves and Cox proportional hazards analysis. Patients with juxtapapillary tumors had a worse prognosis than those with tumors in other locations (64% vs 78% five-year survival), but the difference was not statistically significant. Juxtapapillary location was not an independent risk factor on Cox multivariate analysis. Risk factors included number of epithelioid cells per high-power field, largest tumor dimension, location of the tumor's anterior margin, and invasion to the line of transection. In 63 cases (26%), the tumor was in contact with the optic disc. For these juxtapapillary tumors, we also evaluated the prognostic importance of six variables relevant to juxtapapillary location. On univariate analysis, tumor height at the disc margin, subarachnoid space invasion, and postlaminar optic nerve invasion were significantly related to survival, while disc compression by tumor, prelaminar optic nerve invasion, and extent of disc perimeter surrounded by tumor were not. On Cox multivariate analysis, however, none of these six variables was an independent risk factor. Risk factors for juxtapapillary tumors included number of epithelioid cells per high-power field and location of the tumor's anterior margin.

Choroid Neoplasms↗
PubMed1985

Proton beam irradiation and hyperthermia. Effects on experimental choroidal melanoma.

Ultrasonically induced hyperthermia (4.75 MHz) and proton irradiation (160 meV) were evaluated alone and combined to treat experimental choroidal melanoma in 58 rabbit eyes. Threshold tumoricidal doses were established for each modality. Therapy was performed combining subthreshold doses of heat and radiation. Focused ultrasonic energy via an external beam was found to deliver well-localized heat to an intraocular tumor. Ectopic temperature elevations due to soft-tissue-bone interfaces were alleviated by modifying beam alignment. The results indicate that hyperthermia (43 degrees C for one hour) potentiated the tumoricidal effects of radiation, while sparing normal ocular structures. Therefore, we believe that experimental hyperthermia is suitable as an adjuvant treatment modality. This shows that ultrasound hyperthermia has the potential to increase the efficacy of proton irradiation by lowering radiation doses and thus decreasing posttreatment ocular morbidity in human intraocular malignancies.

Animals↗
PubMed1985

Adrenal "incidentalomas". Need for surgery.

A series of eleven adrenal tumors is presented. Only one of the adrenal tumors showed evidence of endocrine function while eight tumors were incidentally discovered during radiologic evaluations. Surgical exploration was performed in all cases as the final diagnostic measure. There were four malignancies, three nonfunctioning carcinomas, and one neuroblastoma. Two of the four malignancies were discovered incidentally on radiologic evaluation and were considered preoperatively to be benign cystic lesions by radiographic criteria. One benign adrenal hamartoma was diagnosed preoperatively as an adrenal carcinoma. In view of the questionable accuracy of radiologic diagnosis of adrenal masses and the well-documented difficulty in differentiating adrenal adenomas from carcinomas on histologic grounds, consideration should be given to the surgical exploration and excision of all adrenal masses discovered incidentally.

Adenoma↗
PubMed1985

Objective assessment of the malignant potential of intraocular melanomas with standard microslides stained with hematoxylin-eosin.

A method for extracting prognostic information from the cytologic details of intraocular melanomas was developed. With computer assistance, a technician measures the nucleolar area of 200 tumor cells randomly selected from a standard paraffin-embedded microsection stained with hematoxylin-eosin, a procedure that requires approximately 40 minutes with an apparatus that costs less than +30,000. Standard deviation of nucleolar area (SDNA), computed from these measurements, provides an objective assessment of nucleolar pleomorphism. Previous studies showed that second measurements of the same microsection or of the same tumor at different levels yield SDNA values that closely approximate the original measurements. The application of this method to 540 cases from three independent laboratories yielded a correlation of SDNA with death from tumor that was high (P much less than 0.001) and consistent among cases from all three sources. Thus, SDNA provides a clinically useful cytologic measure of the malignancy of intraocular melanomas and may ultimately prove valuable in the assessment of other types of tumors.

Cell Nucleolus↗
PubMed1985

Cryptorchidism: the role of medical education in diagnosis.

The hospital records in a community of 63,000 were reviewed for a five-year period (1978 to 1983) with regard to the diagnosis of cryptorchidism. There were 123 hospitalized patients with unilateral cryptorchidism and 17 patients with bilateral cryptorchidism. The diagnosis was made in 35 newborn infants from a total of 7,380 male births (neonatal incidence 0.48%). The mean age at time of orchiopexy was 7.56 years and only eight of 84 patients were less than 3 years of age at the time of surgery. Inappropriate surgery was done on occasion. A questionnaire mailed to 600 physicians in the region revealed that many were unaware of current recommendations regarding the timing of treatment for undescended testes. Missed diagnosis at birth and uninformed referring physicians appear to be major factors responsible for delayed diagnosis and treatment. Economic factors could not be implicated.

Adolescent↗
PubMed1984

X-ray diffraction study of the polymorphism of hydrated diacyl- and dialkylphosphatidylethanolamines.

The structure and polymorphism of a homologous series of diacyl- and of dialkylphosphatidylethanolamines have been investigated by X-ray diffraction, calorimetry, and density measurement. The compositional dependence of the repeat spacings of the gel (L beta or L beta'), fluid bilayer (L alpha), and inverted hexagonal (HII) phases has been determined both for the short chain length (di-C12) dialkyl didodecylphosphatidylethanolamine (DDPE) and for the long chain length (di-C20) diacyl diarachinoylphosphatidylethanolamine (DAPE). These data, in conjunction with the measured phase transition temperatures obtained both by X-ray diffraction and by differential scanning calorimetry, have been used to construct phase diagrams for the two lipids. DDPE exhibits metastable behavior in the L beta and L alpha phases below 44 degrees C at all water contents and forms cubic and other nonlamellar phases between the L alpha and HII phases. At low water contents, crystalline and fluid phases coexist at temperatures up to 83 degrees C. For DAPE, the behavior is simpler. In the gel phase, the hydrocarbon chains are tilted at 29 degrees to the bilayer normal, and metastability is only observed at water contents below 3 wt %. The L alpha phase is adopted within a narrow temperature range and then transforms directly to the HII phase. The structural parameters of the L beta (L beta'), L alpha, and HII phases of DDPE and DAPE have been calculated from the X-ray data, in conjunction with the measured values of lipid partial specific volume. In addition, the chain-length dependence of the repeat spacings of the phases has been measured for the homologous series of diacyl and dialkyl lipids. Taken together, the results allow a detailed description of the effects of temperature, hydration, and chain length on the polymorphism of the saturated phosphatidylethanolamines.

Calorimetry↗
PubMed1984

Resection of solitary metastasis. Approach to palliative treatment of hepatic involvement with choroidal melanoma.

Local resection was performed as palliative treatment of solitary hepatic metastases from choroidal melanoma in two patients. One patient survived three years after partial hepatectomy, and the second patient was in excellent clinical condition one year after hepatic resection despite radiologic evidence of possible recurrent metastases elsewhere. Our review suggests that local resection of solitary hepatic metastases may constitute an effective approach to palliation of hepatic involvement with uveal melanoma and may possibly lead to longer survival.

Adult↗
PubMed1984

A deficit survival analysis to assess the natural history of uveal melanoma.

A deficit survival analysis was conducted using a retrospective series of 230 patients with uveal melanoma. All underwent enucleation as primary treatment for their disease. Considering the three leading prognostic factors (epithelioid cells per high power field, tumor size, and tumor location), median age was plotted against median survival to determine pathways of disease spread, local and metastatic disease phases, consequences of delayed diagnosis, and the timing of enucleation. The subgroup with all three factors favorable could be subdivided into younger and older subsets on the basis of a bimodal age distribution. Only the older subset could be identified as a local disease state where survival following enucleation corresponded to normal population survival. All remaining subgroups were metastatic because of survival deficits compared to the normal population. Disease tended to progress according to three well defined pathways with 6-8 years required to progress from one subgroup to the next along these paths. These pathways were characterized by constant deficit survivals, suggesting that delays in diagnosis did not translate into loss in survival. Moreover, the value of enucleation as primary therapy can be questioned in the context that it does not appear to alter the natural history of the disease, except for tumors greater than 10 mm in largest dimension which are located anterior to the equator with fewer than 2 epithelioid cells per high power field. Findings suggest that uveal melanoma can be treated by means other than enucleation to allow a chance for prolonged survival with vision preservation.

Adult↗