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Biomedical subjects

E R Katz

Publications and source records attributed to E R Katz.

At least 37 records · Page 2Linked to original sources
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

Sterol phylogenesis and algal evolution.

The stereochemistry of several sterol precursors and end products synthesized by two fungal-like micro-organisms Prototheca wickerhamii (I) and Dictyostelium discoideum (II) have been determined by chromatographic (TLC, GLC, and HPLC) and spectral (UV, MS, and 1H NMR) methods. From I and II the following sterols were isolated from the cells: cycloartenol, cyclolaudenol, 24(28)-methylenecycloartanol, ergosterol, protothecasterol, 4alpha-methylergostanol, 4alpha-methylclionastanol, clionastanol, 24beta-ethylcholesta-8,22-enol, and dictyosterol. In addition, the mechanism of C-24 methylation was investigated in both organisms by feeding to I [2-3H]lanosterol, [2-3H]cycloartenol, [24-3H]lanosterol, and [methyl-2H3]methionine and by feeding to II [methyl-2H3]methionine. The results demonstrate that the 24beta configuration is formed by different alkylation routes in I and II. The Delta25(27) route operates in I while the Delta24(28) route operates in II. Based on what is known in the literature regarding sterol distribution and phylogenesis together with our findings that the stereochemical outcome of squalene oxide cyclization leads to the production of cycloartenol rather than lanosterol (characteristic of the fungal genealogy) and the chirality of the C-24 alkyl group is similar in the two nonphotosynthetic microbes (beta oriented), we conclude that Prototheca is an apoplastic Chlorella (i.e., an alga) and that Dictyostelium as well as the other soil amoebae that synthesize cycloartenol evolved from algal rather than fungal ancestors.

Journal Article↗
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↗
PubMed1988

Conditioned aversions in pediatric cancer patients receiving chemotherapy.

Pediatric cancer patients experiencing nausea/vomiting in anticipation of chemotherapy were studied in comparison to a matched group of patients with no history of anticipatory nausea/vomiting (ANV). Patients with ANV were characteristically more anxious and tended to screen sensory information less selectively than patients without ANV. Parents of patients with ANV relied more heavily on threat of punishment and less on modeling and reassurance when managing their children in fearful situations than did parents of patients with no ANV. ANV was related to an increased incidence of experimentally conditioned taste aversions. The contribution of patient variables to the prediction of ANV and implications for research are discussed.

Adolescent↗
PubMed1987

Biochemical and genetic approaches to microtubule function in Dictyostelium discoideum.

Methods have been developed for analyzing tubulin and microtubules from the cellular slime mold D. discoideum. alpha- and beta-tubulin have been identified on high-resolution 2D gels, and microtubules have been isolated in cytoskeleton preparations from amoebae (White et al., 1983). These studies have revealed properties unique to Dictyostelium tubulin. Amoebal microtubules can be visualized by indirect immunofluorescence, which has aided in the identification of inhibitors which specifically depolymerize microtubules and block amoebae in mitosis. The mitotic inhibitors CIPC, NOC, and TBZ have been used to select resistant mutants which are currently the subjects of biochemical, morphological, and genetic analysis (Katz et al., 1982; White, 1983). One mitotic inhibitor-resistant mutant, CIPC 6, was found to be temperature-sensitive for growth at 27 degrees C as well as CIPC-resistant. At the restrictive temperature amoebae from this mutant are deficient in the passage through mitosis. After incubation for 12 hours at the restrictive temperature, 20% of the CIPC 6 amoebae displayed condensed chromosomes, compared to 2% at the permissive temperature, as determined by Giemsa staining. Examination of the microtubules of this mutant by indirect immunofluorescence showed abnormal spindle microtubule formation at the restrictive temperature, which is the likely cause of the mitotic arrest (White, 1983). Cytoplasmic microtubules were also disrupted in nonmitotic amoebae of CIPC 6 at 27 degrees C. This temperature-sensitive loss of microtubule function suggested the possibility that tubulin from CIPC 6 might be altered. When tubulin from CIPC 6 was examined on 2D gels, no reproducible electrophoretic change was observed from that of the wild type. Through further characterization of mitotic inhibitor-resistant mutants like CIPC 6, more mitotic or microtubule mutants will be identified. Among these mutants, some should contain electrophoretically altered tubulin, microtubule-associated proteins, or components of the amoebal cytoskeleton. Possessing Dictyostelium mutants with known biochemical alterations in cytoskeletal proteins should reveal significant information regarding the function of these proteins in eukaryotic growth and development.

Cytoskeletal Proteins↗
PubMed1986

Caregivers' perceptions of medical compliance in adolescents with cancer.

Two studies were conducted to investigate the prevalence and determinants of gross medical regimen noncompliance among adolescent cancer patients. In the first study, 28 children and adolescents were rated by their primary physicians on various aspects of medical regimen compliance, features of their disease, and treatment regimens. Adolescent patients overall were judged to be significantly less compliant than the younger patients (p less than 0.001), with almost half rated as being "poor" or "very poor" compliers. Poor compliance was judged to be a potential threat to the prognoses of over half of the adolescents studied. Adolescents were reported to experience more severe side-effects and more visible physical residua as a result of their illness and treatment than the younger patients. The second study, conducted at a large pediatric referral center, found far fewer compliance problems among the 65 adolescent patients reviewed, with negative ramifications for treatment outcome reported in only nine patients (14%). The impact of medical variables, patient characteristics, and treatment setting on compliance with antineoplastic therapy is discussed. Issues in compliance assessment and considerations for future research are addressed. It is concluded that routine assessment of compliance is crucial for monitoring patient behavior as well as for the reliable evaluation of treatment protocols.

Acute Disease↗
PubMed1985

Self-induced nystatin resistance in Dictyostelium discoideum.

The cellular slime mold Dictyostelium discoideum is normally susceptible to the action of the polyene antibiotic nystatin. We describe conditions under which transient nystatin resistance can be induced in the absence of detectable changes in sterol composition. These results suggest that nystatin plays a positive role in promoting resistance to itself.

Chromatography, Gas↗
PubMed1985

Anticipatory nausea and vomiting in pediatric cancer patients.

The purpose of this study was to determine the prevalence and correlates of anticipatory nausea and vomiting in a sample of pediatric patients with cancer who were receiving outpatient chemotherapy. Forty male and female patients representing a broad range of diagnoses were interviewed with their parents concerning nausea and vomiting before and after chemotherapy. Anticipatory nausea was reported by 28.8% of the sample; anticipatory vomiting was present in 20% of the sample. An additional 9% had experienced anticipatory nausea and vomiting in the past but not currently. Anticipatory nausea and vomiting was positively correlated with the emetic potential of chemotherapeutic regimens and the severity of nausea and vomiting after chemotherapy; anticipatory nausea and vomiting most often developed within the first 4 months of treatment. Onset of anticipatory nausea and vomiting usually occurred two to four hours before treatment and was most severe at the actual time of drug administration. Considerable interpatient variability was observed, with treatment-related factors accounting for only 22% of the variance in the occurrence of anticipatory nausea and vomiting. These findings are considered within a behavioral framework for understanding conditioned aversions in pediatric patients with cancer. Implications for patient education, future research on the prediction of children at risk, and intervention are discussed.

Adolescent↗