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Biomedical subjects

T W Pendergrass

Publications and source records attributed to T W Pendergrass.

At least 37 records · Page 2Linked to original sources
PubMed1985

Canine cryptorchism and subsequent testicular neoplasia: case-control study with epidemiologic update.

A retrospective study of 2,912 cryptorchid dogs identified 14 breeds with significantly high risk. Among six distinct closely interrelated breed groups (e.g., toy, miniature, and standard poodles), the risk in the smaller breed was always greater than that in the larger relative, suggesting that genetically influenced maldescent could be, in part, related to physical size or the rate of growth of the involved structures. Testicular tumors were diagnosed in 5.7% of the cryptorchid dogs; half had only Sertoli cell tumors, one-third had only seminomas. The relative risk for Sertoli cell tumor or seminoma was not directly related to a familial risk for cryptorchism. Using the health experience of a control population composed of male dogs with anal sac disease (N = 4,184), there is an estimated relative risk of 9.2 in cryptorchid dogs to develop a testis tumor (95% confidence interval, 5.9-14.3) and 4.2 in dogs with inguinal hernia (95% confidence interval, 1.8-9.5). Considering that the anatomical development of the genital tract, testis descent, and tunic relationships in dog are very similar to that in man, and that the associations of cryptorchism and inguinal hernia with testis neoplasms are also similar, the dog should be an excellent model system to further investigate the causes of human cryptorchism.

Animals↗
PubMed1985

Epidemiology of acute lymphoblastic leukemia.

Although the etiology of acute leukemia is largely unknown, some facets of the puzzle are becoming clarified. Recognition of important patterns in age-specific mortality rates has suggested that events early in life, perhaps even prenatally, may have an influence on developing leukemia in childhood. The racial differences evident in mortality, incidence, and immunologic subtype of ALL suggest either differences in exposures to certain "factors" or differences in responses to those "factors" by white children. Hereditary factors appear to play a role. Familial and hereditary conditions exist that have high incidences of acute leukemia. Chromosomal anomalies are common in these conditions. Viral infections may play a role by contributing to alteration in genetic material through incorporation of the viral genome. How that virus is dealt with after primary infection seems important. The presence of immunodeficiency may allow wider dissemination or enhanced replication of such viruses, thereby increasing the likelihood of cellular transformation to an abnormal cell. Proliferation of that malignant cell to a clone may depend on other cofactors. Perhaps prolonged exposure to substances like benzene or alkylating agents may enhance these interactions between virus and genetic material. Does this change DNA repair mechanisms? Are viral infections handled differently? Is viral genomic information more easily integrated into host cells? Ionizing radiation has multiple effects. Alteration in genetic material occurs both at the molecular and chromosomal levels. DNA may be altered, lost, or added in the cell's attempt to recover from the injury. These changes may lead to altered susceptibility to other environmental agents, and host response may be altered. The past 40 years have seen dramatic progress in the treatment of ALL. We have just begun to unravel the complex interactions of genetic makeup, immune response, and the environment on the development of ALL. Whether factors can be identified that may allow prevention of acute leukemia remains to be seen.

Acute Disease↗
PubMed1984

Stature and Ewing's sarcoma in childhood.

The heights and weights of 291 children with Ewing's sarcoma were compared to population norms in order to explore the association of stature with this cancer. Overall, males were not significantly different from what was expected in either height or weight. When weights for heights of males under 151 cm--the upper limit of the norms--were reviewed, the distribution favored the larger categories. Further analysis of this group revealed that males under 151 cm were, on the average, 2 cm shorter and 0.2 kg lighter than peers. By contrast, females were smaller than expected. The greatest difference was in females under 151 cm; they were, on the average, 4.1 cm shorter and 2.4 kg lighter than their peers. In this series of similarly treated patients, stature at diagnosis did not appear to affect survival. Contrary to previous report, attained height and weight at diagnosis do not appear to be important risk factors for children with Ewing's sarcoma.

Adolescent↗
PubMed1982

Improved three-year disease-free survival in osteogenic sarcoma.

Of 41 consecutive patients with newly diagnosed osteogenic sarcoma admitted to the Children's Orthopedic Hospital and Medical Center in Seattle, Washington, between 1952 and 1977, 19 treated before 1973 did not receive adjunctive chemotherapy (histological group) whereas after 1972 22 have been so treated (chemotherapy group). Chemotherapy consisted primarily of high doses of methotrexate and adriamycin for 16 months after surgical treatment. Patients in the historical group have been observed for a minimum of nine years (six patients) or until death (13 patients). The 13 surviving patients in the chemotherapy group have been followed for a minimum of three years (median five years) and all 12 disease-free patients have been off therapy for between one and a half and five and a half years (median three years). Overall, the chemotherapy group has had a significant increase in both survival (p = 0.03) and disease-free survival (P = 0.02) compared to the historical group. In 35 patients with localised disease at diagnosis, the three-year disease-free survival and the three-year survival rates were 18 per cent and 41 per cent respectively in the historical group, and 67 per cent and 78 per cent (life table estimates) respectively in the chemotherapy group. With adjunctive chemotherapy only one of the seven patients developing pulmonary metastases did so later than nine months after diagnosis. The superior results in the chemotherapy group could not be accounted for by differences in age, sex, presence of metastases at diagnosis, histopathology, location of primary tumour, type of initial or subsequent surgical treatment, or the use of standard or computerised lung tomography. Although the use of historical controls in this study does not exclude other changes as contributing to the observed improvement in outcome, our data support the contention that adjunctive chemotherapy improves both the disease-free survival and the overall survival of patients with osteosarcoma and rarely delays the onset of recurrent or metastatic disease.

Adolescent↗
PubMed1981

Development of an education program for parents of children with cancer.

A structured education program for parents of children with cancer has been developed and has undergone pilot testing. Content included both medical and psychosocial materials. The parent education program supplemented the existing educational and emotional support services of a large, childhood cancer treatment center. Written materials, self-instructional exercises, lectures, visual aids, and small group discussions were incorporated into the program. This variety of topics and teaching techniques was appealing to parents and appeared to enhance learning. Parents enthusiastically attended the program pilots, gained and retained the new information, and appeared to benefit emotionally from their participation.

Child↗
PubMed1981

Knowledge and use of "alternative" cancer therapies in children.

Because of the increased interest in laetrile and other "alternative" cancer therapies among cancer patients and the lack of data concerning knowledge and use of such treatments in childhood cancer, parents of children diagnosed with cancer in 1977 and 1978 at a major pediatric oncology center were surveyed. Eight different "alternative" therapies or groups were known by 50% of parents. Seventeen of 106 children had received an "alternative" cancer treatment. News media were the most frequent initial information source. Accuracy of knowledge of toxic effects of laetrile was poor, with only 26.4% realizing poisoning was possible. Parents who felt desperation in their search for a cure and were looking for an easier treatment method, and those who were dissatisfied with their role in making treatment decisions, appeared at greatest risk of seeking "alternative" therapies. Over 56% of parents wanted more information about cancer and its treatment, with written information favored by almost 40%.

Adolescent↗
PubMed1980

Incidence of retinoblastoma in the United States.

Data from the population-based Surveillance, Epidemiology, and End Results Program of the National Cancer Institute were used to calculate the incidence of retinoblastoma for the years 1974 through 1976. Each year 3.58 cases occurred for each million children under the age of 15 years. Incidence was markedly age related, with over 90% of the cases being diagnosed before the age of 5 years. Although no difference in incidence was found for whites and blacks, other nonwhites had rates greater than four times those of whites. Twenty percent of patients had bilateral disease. Treatment patterns revealed that surgery remains the most common treatment modality. Review of patterns of survival suggested that children in the other nonwhites category with unilateral disease had poorest survival rates.

Adolescent↗
PubMed1979

The role of genetic factors in the etiology of Wilms' tumor: two pairs of monozygous twins with congenital abnormalities (aniridia; hemihypertrophy) and discordance for Wilms' tumor.

Wilms' tumor was diagnosed in two children each of whom has an identical twin. In one of the pairs of twins the aniridia syndrome with psychomotor retardation was present in both children, but Wilms' tumor was found in only one. In the other twins hemihypertrophy as well as Wilms' tumor were identified in one child, whereas neither of these abnormalities was present in her twin sister. These findings lend support to a hypothesis that the development of Wilms' tumor requires the occurrence of two successive mutational events, one of which may be a germinal mutation. The presence of aniridia, hemihypertrophy, or other associated congenital abnormalities may aid in distinguishing between hereditary and sporadic forms of Wilms' tumor.

Abnormalities, Multiple↗
PubMed1976

Canine testicular tumors: epidemiologic features of 410 dogs.

Histologically confirmed testicular tumors were diagnosed in 410 dogs from 12 North American veterinary university hospitals and clinics. Three tumor-cell types, Sertoli cell tumor, interstitial cell tumor and seminoma, were about equally represented. Several breeds were identified with high risk for different testicular tumor-cell types. Cytogenetic and immunogenetic studies of these dog families could offer leads applicable to familial testicular cancer in man. The multiplicity of breeds within the series suggests that, as in man, other factors, in addition to hereditary, play a role in etiology. Cryptorchid dogs appear to have a 13.6 times higher risk of testicular tumor than normal dogs. Additionally, male dogs with an inguinal hernia have an increased risk (4.7) of testis tumors. There were no detectable excesses of other urogenital anomalies or urogenital tumors among the series. The Shetland Sheepdog is suggested as an appropriate model for research into the mechanisms responsible for testicular maldescent and tumorigenesis.

Age Factors↗
PubMed1976

Congenital anomalies in children with Wilms' tumor: a new survey.

From 68 hospitals in the National Wilms' Tumor Study, records of 547 patients showed six patients with aniridia, 16 with hemihypertrophy, and 24 with genitourinary abnormalities. Multiple cases of Wilms' tumor occurred in three families. The results confirm high frequencies of aniridia and genitourinary anomalies in patients with Wilms' tumor, and show that concurrence with hemihypertrophy may be more often recognized or recorded now than it was ten years ago. The results demonstrate the desirability of developing checklists for other childhood neoplasms some of which have their own constellation of anomalies.

Child↗
PubMed1975

Acute myelocytic leukaemia and leukaemia-associated antigens in sisters.

In a sibship of 5 brothers and 7 sisters, 3 sisters died from acute myelocytic leukaemia while a 4th probably had the same disease. Laboratory studies on the close relatives revealed that a 5th sister had persistently high erythrocyte sedimentation-rates and serum-IgM levels and serological evidence of acute leukaemia-associated antigens. These findings suggest a possible preleukaemic state in this patient.

Acute Disease↗
PubMed1975

Occurrence of nervous-tissue tumors in cattle, horses, cats and dogs.

From 11 North American veterinary university hospitals and clinics, 248 animals were a confirmed diagnosis of nervous-tissue tumor were identified; 7 tumors were found in cattle, 28 in horses, 14 in cats, 199 in dogs, and none in other species. Tumors were divided for analysis into three categories-glial, meningeal, and peripheral nerve. In cattle and horses, all tumors involved peripheral nerves, the risk of which, in horses, reached a plateau at 4-6 years of age and remained constant thereafter. In cats, the tumors were equally distributed among the three tumor categories whereas, in dogs, twice as many glial tumors as meningeal and peripheral nerve tumors were found. The risk for glial tumors in dogs reached a peak at 10-14 years of age, for meningeal at 7-9 years, and for peripheral nerve at 2-3 and 7-9 years. Three canine breeds-English bulldog, boxer, and Boston terrier-had an excessive rish of glial tumors. Except for an excess of skin tumors in dogs with peripheral nerve tumors, there was no unusual occurrence with second primary neoplasms for any species. There was no detectable predisposition by sex for any of the categories of nervous-tissue tumors among any of the four species. The role of genetic abnormalities associated with nervous-tissue tumors and other etiologic factors (e.g., chronic hypoxia) may be clarified by further studies involving canine breeds of "bulldog" ancestry.

Age Factors↗
PubMed1975

Prognosis of black children with acute lymphocytic leukemia.

To assess the racial differences in survival of children with acute lymphocytic leukemia, we analyzed data for 1,675 white and 126 black children, diagnosed from 1955 to 1969. Blacks had a significantly shorter median survival and lower one-year and three-year survival rates than whites. There was substantial variation in racial differences by age. In addition, much of the variation between races seemed to be due to socioeconimic factors rather than strictly racial ones. Identification of the specific factors responsible for the poorer survival of children from lower social classes is sorely needed.

Adolescent↗
PubMed1975

Cryptorchism and related defects in dogs: epidemiologic comparisons with man.

In a study of 1266 dogs with cryptorchism from a large clinic/hospital series 8 breeds were found to be at excess risk of the defect and 3 breeds at significantly low risk. Review of the medical histories revealed that hip dysplasia, patellar dislocation, defects of the penis and prepuce, and umbilical hernia were excessively associated with cryptorchism. Testicular tumors were diagnosed 10.9 times more commonly among cryptorchid dogs. The epidemiologic features of canine cryptorchism were compared with those in man. Cryptorchid dogs could be used as models for etiologic research.

Animals↗
PubMedDate not supplied

Retinoblastoma.

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Child, Preschool↗