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Biomedical subjects

E R Katz

Publications and source records attributed to E R Katz.

18 recordsLinked to original sources
PubMed1991

Evidence for the presence of a growth factor in Dictyostelium discoideum.

Polypeptide hormones, recognized for their ability to regulate cell growth and differentiation, have been classified as growth factors. These growth factors have been extensively described in higher eukaryotic organisms and cell lines [Hedin and Westermark, Cell 37:9-20, 1984]. Here we report the identification and partial characterization of a putative growth factor present in vegetative amoebae of the cellular slime mold Dictyostelium discoideum. A mutant was selected and found to be temperature sensitive due to the absence of an extracellular protein suggestive of a growth factor. The putative growth factor (DGF) is a protein resistant to both heat and strong detergent treatment but sensitive to reducing agents. The physiological significance of DGF is as yet unknown. DGF is of interest both in relation to understanding the events which control cell proliferation in Dictyostelium and in its relationship to other known growth factors.

Dictyostelium↗
PubMed1991

Memory for spatial location in retarded and nonretarded persons.

Item memory and memory for spatial location were examined in college students, mildly retarded persons and moderately retarded persons. They performed under semantic or nonsemantic encoding instructions to remember pictures presented in a large book. Recall and relocation (unexpected) tests followed immediately after studying the pictures and, again, 24 h later. Mildly retarded persons were deficient in memory for items (effortful processing), but not in memory for location (automatic processing). Moderately retarded persons were deficient in both types of memory. Additionally, there were IQ-related differences in the long-term memory of location information, as well as item information. Location memory, as opposed to item memory, was shown to be (1) sensitive to encoding instruction, (2) insensitive to differences in intelligence, and (3) more sensitive to long-term forgetfulness.

Adolescent↗
PubMed1990

Cognitive functioning in long-term survivors of childhood leukemia: a prospective analysis.

Treatment-related cognitive impairments have been reported for survivors of childhood leukemia following prophylactic central nervous system (CNS) treatment with 2400 cGy craniospinal irradiation and intrathecal chemotherapy. The present study was designed to prospectively evaluate cognitive functioning of 24 children prior to CNS prophylaxis of 1800 cGy of craniospinal irradiation and intrathecal drugs, and at intervals of 1 and 4-5 years. At diagnosis, prior to CNS treatment, all 24 subjects performed in the average range of intelligence, as measured by the Wechsler Intelligence Scales. Subjects continued to perform in the average range with no significant declines at the 1-year follow-up. Significant declines in cognitive functioning, however, were found at the 4- to 5-year follow-up period, with five subjects (21%) performing in the low average or borderline levels of intelligence. Of the 19 subjects performing in the average range, five showed significant discrepancies between Verbal and Performance IQ scores. Nine subjects exhibited poor performance on a subtest cluster assessing perceptual and attentional processes. With regard to school experiences, 50% of the subjects had received some type of special education services. The findings indicate the need for annual evaluations of cognitive functioning in long-term survivors of childhood leukemia who received 1800 cGy craniospinal irradiation, to identify potential cognitive late effects of treatment requiring appropriate special education services.

Adolescent↗
PubMed1989

Development of behavioral distress in reaction to acute pain in two cultures.

Studied developmental and gender differences in distress behavior during separate phases of a medical treatment in 2 cultures. Distress reactions of 175 children with cancer (age 8 months-18 years 7 months) were observed during bone marrow aspirations (BMA) in 2 different treatment centers (one in the United States, one in The Netherlands) using a behavioral checklist (Procedure Behavioral Rating Scale). The BMAs contained a preparatory phase, the actual needle introduction, and a recovery period. In both cultures almost all separate distress behaviors occurred less in older children, except for increasing muscle tension during the actual puncture. Distress was highest during the needle introduction and significantly lower during the preparatory and recovery phases; in addition, somewhat different patterns of distress behavior were found in separate phases. Culture and sex differences were found. The latter were less robust than developmental and phase differences.

Adolescent↗
PubMed1989

Identification and characterization of catA, a mutation causing catalase deficiency in Dictyostelium discoideum.

Various strains of Dictyostelium discoideum were assayed for catalase activity. We were able to demonstrate the presence of catalase in lysates of all strains tested except one, ts12m. Lysates of this strain did not show any detectable level of catalase. The increased sensitivity of intact ts12m amoebae to hydrogen peroxide was consistent with the catalase deficiency. We followed catalase activity through a developmental time course for the wild type (Ddb) and were able to show its presence throughout development. No catalase activity was detected from ts12m in any stage of development. The growth and development of this acatalasemic strain of D. discoideum was no different than those of the wild type. The mutation, catA, was assigned to linkage group II.

Catalase↗
PubMed1989

Assessment and management of chronic and recurrent pain in children with chronic diseases.

This paper provides an overview to the assessment and management of chronic and recurrent pain in children with chronic diseases. Relevant clinical research studies are cited, and practical guidelines are provided for the differential assessment and management issues inherent in the comprehensive care of chronic and recurrent pain in children and adolescents with hemophilia, juvenile rheumatoid arthritis, sickle cell disease, and cancer.

Child↗
PubMed1989

Behavioral distress in pediatric patients with cancer receiving chemotherapy.

The purpose of this study was to assess prospectively the behavioral effects of chemotherapy in children and adolescents with cancer. A total of 94 patients, with a range of malignancies and chemotherapy protocols, were evaluated 1, 4, and 7 months after treatment initiation. Assessments focused on behavioral distress symptoms and nausea/vomiting experienced in anticipation of chemotherapy and following its administration. Significant disturbances were described in a variety of domains, with adolescents exhibiting consistently higher levels of behavioral symptoms and nausea/vomiting than younger children. Behavioral distress tended to decrease and stabilize throughout time for children and to increase throughout time for adolescents. Age differences in behavioral distress were independent of the emetogenicity of therapy given to younger and older patients. The interaction of biologic and psychosocial factors in determining treatment-related distress is discussed, along with implications for future predictive and intervention studies.

Adolescent↗
PubMed1979

Benign giant adrenal cyst and parathyroid adenoma: a case report.

An unusual case of a benign adrenal cyst and a parathyroid adenoma occurring in a 59-year-old man with hypercalcemia is reported. Excretory urography, ultrasound, renal aortography, computerized axial tomography and selective thyroid venous sampling were used to establish a diagnosis. Left adrenalectomy was done because of a suspicion of malignancy, which was followed by excision of a retrolaryngeal parathyroid adenoma.

Adenoma↗
PubMed1978

Isolation and characterization of the RNA of membrane-bound ribosomes in Dictyostelium discoideum.

The RNA of membrane-bound ribosomes, isolated from Dictyostelium discoideum, represented 13 to 16% of the total ribosomal RNA (rRNA) present throughout growth and development. Membrane-bound ribosomes were released by treatment with sodium deoxycholate and Brij 58. There were no obvious differences in size and base composition between RNAs derived from membrane-bound or free ribosomes. The 17S membrane-bound rRNA and free rRNAs appeared to have similar methyl contents. However, the 25S membrane-bound rRNA contained about 16 to 20% fewer methyl groups than the 17S membrane-bound rRNA and free rRNAs. Free rRNAs turned over rapidly during early development but not during the disaggregation and reaggregation processes. Membrane-bound rRNAs showed very little turnover during the early stages of morphogenesis, but showed rapid turnover during the late stages of development; this class of rRNAs did not turn over during early stages of reaggregation but turned over rapidly during later stages of reaggregation.

Cell Fractionation↗
PubMed1977

Isolation and characterization of transfer RNAs from Dictyostelium discoideum during growth and development.

Transfer RNAs and aminoacyl-tRNA synthetases were isolated from vegetative and developing cells of the cellular slime mode Dictyostelium discoideum. Using the homologous synthetases, the tRANs were compared for their levels of acceptance of 17 amino acids. These levels were found to be the same. The tRANs were further compared by double label chromatography on reversed phase columns. Some major quantitative differences in individual peaks were observed. In addition, for a number of aminoacyl-tRNAs, small but reproducible displacements of individual peaks were apparent. In many cases the displacement was in the major peak, and in all but one case the developmental peak eluted ahead of the vegetative peak. Taken together, these results suggest that there is no change from growth to development in the transcription of tRNA genes, but that there are important changes in post-transcriptional modification.

Amino Acyl-tRNA Synthetases↗
PubMed1976

Ruptured mycotic aortic aneurysm.

A right flank mass, in a patient with fever of unknown origin, pain, and superiorly displaced right kidney on excretory urogram, was explored through a subcostal incision. Finding of a retroperitoneal abscess was anticipated; instead of a ruptured mycotic aortic aneurysm was encountered. An awareness that entities such as this may exist is imperative in the differential diagnosis of flank masses. Treatment through a flank incision presents an elusive if not impossible feat. Because of the gravity of the underlying disease, misdiagnosis almost always results in death.

Abscess↗
PubMed1976

Priapism: an unusual complication of parotitis without orchitis.

A 10-year-old white boy is described in whom priapism developed as a complication of parotitis without orchitis. Medical study failed to reveal any other etiology. The syndrome was assumed to be related to a mumps virus. Treatment by corpora cavernosa-spongiosum shunt relieved the acute symptoms as well as preserved the patient's ability to have an erection.

Child↗
PubMed1975

Genetic map of the beginning of the rIIB cistron of bacteriophage T4.

In this report the herefore uncharacterized mutants at the beginning of the rIIB cistron of bacteriophage T4 have been connected to the main part of the map and have been shown not to be in any way unusual. The temperature sensitive mutant HD263 appears to be the earliest mutant in the cistron.

2-Aminopurine↗