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Biomedical subjects

W W Johnson

Publications and source records attributed to W W Johnson.

At least 73 records · Page 4Linked to original sources

Quantifying the cognitive trajectories of extrapolated movements.

Subjects' extrapolations of a piecewise constant-velocity trajectory and a constant-acceleration trajectory were mapped out over a sequence of trials that required only a button-press response. Without any performance feedback, subjects' extrapolations of both trajectories approximated an acceleration segment followed by a constant-velocity segment. With performance feedback, subjects' extrapolations of the constant-acceleration trajectory approached optimal performance. Subsequent withdrawal of the feedback shifted the entire extrapolated trajectory. These feedback-related changes in the extrapolated trajectory can be interpreted as changes in two parameters of a cognitive representation of the movement pattern.

Cognition↗

Light and immunoelectronmicroscopic study of Hodgkin's disease: evidence of immunoglobulin synthesis by tumor cells.

The direct immunoperoxidase technique with peroxidase-conjugated F(ab')2 fragments was used at the light and electron microscopic levels to identify intracytoplasmic immunoglobulin (CIg) components in malignant cells of Hodgkin's disease. In each of the 27 cases studied, Hodgkin and Reed-Sternberg cells contained either IgG or IgM, with both light chains often present simultaneously. The number of IgG-positive malignant cells was inversely related to changes in the lymphoid compartment, as defined by the Rye grading system. The evolution from lymphocytic predominance to lymphocytic depletion was paralleled by a decrease of IgM-positive cells and by a substantial increase (to exclusiveness) of IgG-containing cells. These immunoelectronmicroscopic studies disclosed definite morphologic evidence of CIg synthesis by Hodgkin, Reed-Sternberg and lacunar cells. The immunoglobulin components were also synthesized by lymphoid B cells at different levels of modulation. Immunoglobulin synthesis by malignant cells was localized in perinuclear zone, on free cytoplasmic ribosomes and profiles of rough endoplasmic reticulum. The results of this joint light and electron microscopic study support the view that Hodgkin, Reed-Sternberg and lacunar cells belong to the B-cell compartment within Hodgkin's disease.

B-Lymphocytes↗

Treatment of childhood rhabdomyosarcoma at St. Jude Children's Research Hospital, 1962--78.

Between March 1962 and December 1978, 153 children with rhabdomyosarcoma (RMS) received treatment at St. Jude Children's Research Hospital. As of January 1979, 62 of these patients were still alive. Between 1962 and 1968, 20 patients were not treated by protocol, and, between 1968 and 1979, another 13 have been registered as "nonprotocol"; 6 of these 33 patients survive. Since 1968, 120 patients received treatment by 3 stage-related, multiple-modality programs. In the first protocol, chemotherapy consisted of vincristine, cyclophosphamide, and dactinomycin; 14 of 34 patients have survived after 6 to more than 10 years. In the second treatment program, which used adriamycin in addition to the 3 drugs cited above, 20 of 56 subjects remain free of disease after more than 2 to 5.5 years; toxicity of the multiple agents given in combination with radiotherapy proved intolerable and led to a modified 4-agent protocol for patients admitted since early 1977. Of 30 in this latter group, 22 are alive. Forty of 44 patients who remained free of RMS for more than 2 years continue to survive.

Adolescent↗

Stage-related combined modality treatment of retinoblastoma. Results of a prospective study.

Forty-two consecutive patients with retinoblastoma were evaluated by a new staging system and combined modality therapy instituted according to stage. Nineteen patients had bilateral tumors and 23 had unilateral tumors. The staging system was effective in identifying subpopulations of patients and successfully predicted those at greater risk of recurrence or death. Thirty-nine of 42 patients survive (Median survival time, 42 months). Two of 4 children with tumor extension beyond the eye died while 37 of 38 children with tumor presumed confined to the eye survive. Toxicity of the chemotherapy was mild. Radiation therapy of intraocular tumor was associated with cataract formation but most children had satisfactory vision after extraction and the use of corrective lenses. Ophthalmologic findings did not always correlate with histologic extent of tumor and both should be used in planning and evaluating treatment. Recommendations are made on the role of chemotherapy and the need to reduce the morbidity of treatment.

Child↗

Sarcomatous renal tumor of childhood. An electron microscopic study.

A review of 106 cases of Wilms' tumor revealed five examples of a distinctive, monomorphic, sarcomatous renal tumor. Electron microscopic studies suggested that such tumors have their origin from the blastemal cap cells of the developing metanephros. These variants of Wilms' tumor are more likely to metastasize to bone and have a poorer prognosis than the usual type of nephroblastoma.

Child↗

Malignant "histiocytic" lymphoma in childhood.

Forty-one cases of childhood "histiocytic" lymphoma were studied morphologically and immunologically to determine whether this tumor type is composed of true histiocytic cells. Lysozyme and alpha-1-antichymotrypsin were used as markers for histiocytes, and cytoplasmic immunoglobulins were used as markers for B cells. Both indirect immunofluorescence and immunoperoxidase methods were used for functional characterization of tumor cells. Eight different subgroups were identified in the series, and only one case was proved to be true histiocytic lymphoma. When survival was evaluated for different subgroups, excluding convoluted lymphocytic, unclassified, and true histiocytic lymphomas, mixed follicular cell lymphoma had the most favorable prognosis; six of seven patients survived for at least one year. Immunoblastic lymphoma, by contrast, had an unfavorable prognosis; none of four patients were alive one year after diagnosis. The difference is statistically significant (P < 0.05) by chi-square analysis. Other groups of lymphoma (large cleaved, large noncleaved, and small noncleaved) had an intermediae prognosis (three of five, six of nine, and five of nine patients surviving at one year). Our results indicate that "histiocytic" lymphoma is a morphologically heterogeneous group of neoplasms, mostly not related to true histiocytes, and that morphologic subclassification may be useful in predicting prognosis.

Child↗

Dystrophic degeneration of papillary muscle and ventricular myocardium. A basis for mitral valve prolapse in Duchenne's muscular dystrophy.

The hearts of three children who died with Duchenne's progressive muscular dystrophy and features of mitral valve prolapse were examined to find if the valve disorder arose from cardiomyopathy due to the primary disease or from dystrophic changes in th mitral valve itself. Gross, histologic and ultrastructural features of mitral valve annulus, anterior and posterior leaflets, chordae tendineae, right and left ventricles, and anterior and posterior papillary muscles were compared with those of similar tissues from normal children of matched age and sex. Fibrosis and myofibrillar lysis--most extensive in posterior papillary muscle and in the posterobasal segment of the left ventricle--were the main histopathologic findings. Myofibrillar lysis was characterized by a total loss of actin and myosin myofilaments. By contrast, the mitral valve annulus, its leaflets and the origin, distribution pattern, length and thickness of chordae tendineae were entirely normal. These observations establish that mitral valve prolapse syndrome in Duchenne's dystrophy is an expression of cardiomyopathy involving papillary muscle and ventricular myocardium rather than a result of dystrophic changes in the mitral valve leaflets, annulus or chordae tendineae.

Adolescent↗

Antimyosin and antirhabdomyoblast sera: their use for the diagnosis of childhood rhabdomyosarcoma.

Antisera against myosin of human normal skeletal muscle and against rhabdomyoblasts of autopsy-proved rhabdomyosarcoma were raised in white rabbits, purified, and assessed for their usefulness in the diagnosis of childhood rhabdomyosarcoma. The specificity of the antisera was tested by both immunofluorescence and immunoperoxidase methods in seven cases of autopsy-proved rhabdomyosarcoma, five of malignant lymphoma, three of neuroblastoma, and two of Ewing's sarcoma. Antimyosin serum tested positive for all cases of rhabdomyosarcoma and negative for other types of tumor. Antirhabdomyoblast serum was positive in all cases of rhabdomyosarcoma and cross-reacted with cases of neuroblastoma and Ewing's tumor, although the intensity of staining was much decreased. Our results indicate that antimyosin serum is specific for childhood rhabdomyosarcoma and can be used to differentiate this from other childhood "round cell" tumors.

Adolescent↗