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D Chase

Publications and source records attributed to D Chase.

At least 37 records · Page 2Linked to original sources
PubMed1996

A comparative study of apoptosis and cell proliferation in infantile and adult fibrosarcomas.

The infantile fibrosarcoma, a rare tumor phenotypically similar to the adult fibrosarcoma, frequently has a benign course marked by spontaneous regression. Because biologic mechanisms responsible for this regression remain unexplained, an investigation of the role of apoptotic cell death is warranted. The rate of apoptotic cell death has been compared in five cases each of infantile and adult fibrosarcoma by quantitative estimation of in situ DNA double strand breaks. Although positively stained apoptotic cells are evident in all 10 cases, the apoptotic index is significantly higher in infantile cases (mean 6.6% +/- 0.80) compared to adult cases (mean 0.5% +/- 0.08). The proliferative (MIB-1) index of each specimen has been calculated by immunostaining for cell cycle phase-dependent Ki-67 antigen with MIB-1 antibody. Infantile cases have a significantly lower proliferative (MIB-1) index (mean 0.4 +/- 0.15) than adult counterparts (mean 15.9 +/- 3.76). The relatively benign course of the infantile fibrosarcoma may be due to two factors--a significantly lower proliferative (MIB-1) index coupled with enhanced apoptosis.

Adult↗
PubMed1994

Performance reporting of health care delivery systems: will it make the grade?

Recently, federal governments, state governments, and private sector groups have begun initiatives that would report the performance of health plans in key areas. United HealthCare Corporation's experience in developing and publicly releasing "report cards" for 15 of its health plans may prove useful as other efforts go forward. There are both advantages and challenges to producing a report card in terms of resource investment, directing health plans toward performance improvement, and the ability for both purchasers and policy makers to understand and make use of results. These and other issues will be important to consider as other segments of the health care industry, particularly providers, focus on reporting performance measures.

Consumer Behavior↗
PubMed1994

Dissection of the ADR1 protein reveals multiple, functionally redundant activation domains interspersed with inhibitory regions: evidence for a repressor binding to the ADR1c region.

The yeast transcriptional activator ADR1 is required for expression of the glucose-repressible alcohol dehydrogenase gene (ADH2), as well as genes involved in glycerol metabolism. The N-terminal half of the ADR1 protein was shown to contain three separate transactivation domains, including one (TADI) that encompasses the zinc finger DNA-binding domain. While TADII and TADIII were shown to be functionally redundant in activating ADH2 expression, deletion of only TADIII impaired ADR1 control of glycerol metabolism genes. None of these activation domains appeared to be carbon source regulated when separated from the ADH2 promoter context. Interspersed among these activation domains were two regions which, when removed, increased ADR1 activity; one was localized to the site of ADR1c mutations (residues 227 to 239) that allow glucose-insensitive ADH2 expression. The 227-to-239 region blocked ADR1 activity independently of the TAD present on ADR1, ADR1 DNA binding, and specific ADH2 promoter sequences. In addition, this region inhibited the function of a heterologous transcriptional activator. These results are consistent with the existence of an extragenic factor that binds the ADR1c region and represses ADR1 activity and suggest that other factors are responsible for aiding ADR1 in the carbon source regulation of ADH2.

Alcohol Dehydrogenase↗
PubMed1992

Molecular cloning of higher-plant 3-oxoacyl-(acyl carrier protein) reductase. Sequence identities with the nodG-gene product of the nitrogen-fixing soil bacterium Rhizobium meliloti.

cDNA clones encoding the fatty-acid- biosynthetic enzyme NADPH-linked 3-oxoacyl-(acyl carrier protein) (ACP) reductase were isolated from a Brassica napus (rape) developing seed library and from an Arabidopsis thaliana (thale cress) leaf library. The N-terminal end of the coding region shows features typical of a stromal-targeting plastid-transit peptide. The deduced amino acid sequences have 41% and 55% identity respectively with the nodG-gene product of Rhizobium meliloti, one of the host-specific genes that restrict infectivity of this bacterium to a small range of host plants. The probability that the nodG-gene product is a oxoreductase strengthens the hypothesis that some of the host-specific nod-gene products are enzymes which synthesize polyketides that uniquely modify the Rhizobium nodulation signal molecule.

3-Oxoacyl-(Acyl-Carrier-Protein) Reductase↗
PubMed1992

ADR1c mutations enhance the ability of ADR1 to activate transcription by a mechanism that is independent of effects on cyclic AMP-dependent protein kinase phosphorylation of Ser-230.

Four ADR1c mutations that occur close to Ser-230 of the Saccharomyces cerevisiae transcriptional activator ADR1 and which greatly enhance the ability of ADR1 to activate ADH2 expression under glucose-repressed conditions have been shown to reduce or eliminate cyclic AMP-dependent protein kinase (cAPK) phosphorylation of Ser-230 in vitro. In addition, unregulated cAPK expression in vivo blocks ADH2 depression in an ADR1-dependent fashion in which ADR1c mutations display decreased sensitivity to unregulated cAPK activity. Taken together, these data have suggested that ADR1c mutations enhance ADR1 activity by blocking cAPK phosphorylation and inactivation of Ser-230. We have isolated and characterized an additional 17 ADR1c mutations, defining 10 different amino acid changes, that were located in the region defined by amino acids 227 through 239 of ADR1. Three observations, however, indicate that the ADR1c phenotype is not simply equivalent to a lack of cAPK phosphorylation. First, only some of these newly isolated ADR1c mutations affected the ability of yeast cAPK to phosphorylate corresponding synthetic peptides modeled on the 222 to 234 region of ADR1 in vitro. Second, we observed that strains lacking cAPK activity did not display enhanced ADH2 expression under glucose growth conditions. Third, when Ser-230 was mutated to a nonphosphorylatable residue, lack of cAPK activity led to a substantial increase in ADH2 expression under glucose-repressed conditions. Thus, while cAPK controls ADH2 expression and ADR1 is required for this control, cAPK acts by a mechanism that is independent of effects on ADR1 Ser-230. It was also observed that deletion of the ADR1c region resulted in an ADR1c phenotype. The ADR1c region is, therefore, involved in maintaining ADR1 in an inactive form. ADR1c mutations may block the binding of a repressor to ADR1 or alter the structure of ADR1 so that transcriptional activation regions become unmasked.

Amino Acid Sequence↗
PubMed1990

In vitro and in vivo cytotoxicity of rhodamine 123 combined with hyperthermia.

Because both Rhodamine 123 (R123) and hyperthermia have been shown to be cytotoxic, we examined their effect, independently and in combination, on five different human malignant cell lines in vitro and on cultured melanoma cells grown intradermally in nude mice. The cell lines examined include two human melanomas, UCLA-SO-M14 and UCLA-SO-M21, the colon cancer cell line HT29, the human lung cancer cell line P3, and the human breast cancer cell line B231. R123 and hyperthermia, when used in combination, were found to be cytotoxic for these five different human malignant cell lines in vitro. The two agents together appear to enhance the cytotoxic effect of each alone, as documented by synergistic ratios ranging from 2.31 to 45 for the different cell lines. In the "nude" mouse model, animals were treated with a combination of R123 and hyperthermia (43 degrees C for 90 min). A statistically significant (P = 0.04) decrease in tumor growth rate was observed when compared with the rate of tumor growth in untreated animals. The results suggest a potential role for R123 in combination with hyperthermia in the treatment of malignant cells.

Animals↗
PubMed1990

Malignant mixed müllerian tumor of the oviduct.

Malignant mixed müllerian tumor is an uncommon gynecologic neoplasm, especially in the oviduct, where fewer than 30 have been described. We report two additional cases which clinically mimicked carcinoma of the oviduct. Both patients were postmenopausal and had the chief complaint of abdominal pain associated with increased abdominal girth. Presurgical vaginal cytologies were negative and both diagnoses were made only with histologic examination of tissues removed at surgery. As most of the cases from the literature involved low-parity women, the high parity of these women is unusual. Unfortunately both presented with stage III disease and died of recurrent disease 18 and 12 months following surgery.

Fallopian Tube Neoplasms↗
PubMed1988

Morphology as a basis for taxonomy of large spirochetes symbiotic in wood-eating cockroaches and termites: Pillotina gen. nov., nom. rev.; Pillotina calotermitidis sp. nov., nom. rev.; Diplocalyx gen. nov., nom. rev.; Diplocalyx calotermitidis sp. nov., nom. rev.; Hollandina gen. nov., nom.[TRUNCATED].

The purposes of this paper are (i) to present a framework for the morphometric analysis of large uncultivable spirochetes that are symbiotic in wood-eating cockroaches and termites; (ii) to revive, in accordance with the rules of the International Code of Nomenclature of Bacteria, the names of three genera (Pillotina, Diplocalyx, and Hollandina) and three species (Pillotina calotermitidis, Diplocalyx calotermitidis, and Hollandina pterotermitidis) for the same organisms to which the names were originally applied, because these names were not included on the 1980 Approved Lists of Bacterial Names; and (iii) to formally propose the name Clevelandina reticulitermitidis for a new genus and species of spirochetes from the termite Reticulitermes tibialis. None of these genera and species has been cultivated either axenically or in mixed culture; hence, all are based on type-descriptive material.

Animals↗
PubMed1987

Treatment of patients with stage IV cancer: do the ends justify the means?

Most experienced head and neck surgeons recommend aggressive treatment--including radical surgery--for patients with resectable Stage IV cancers. Yet, given the poor overall cure rate of 15% and the deformity and disability often associated with treatment, one of the most frequently asked questions at our conference on tumors was: Are we really helping these patients? We found little data in the relevant literature to answer this or other questions. Are there subgroups with a better outlook? What is the evidence for palliation in the 85% of patients who fail treatment and how is it best achieved? How do patients and their families view their treatment in retrospect? To find the answers, we studied the records of 76 consecutive patients (previously untreated) who presented with Stage IV carcinoma of the upper aerodigestive tract in 1981-82. We also interviewed surviving patients or family members and friends by phone. Overall mean survival was 15 months, with a 2-year disease-free survival rate of 16%. More to the point, resectable patients treated with curative intent had a mean survival of 19.4 months, and 12 of 42 patients (29%) were disease-free at 2 years. Patients with laryngeal cancer had the best survival results, and patients with sinus cancers had the worst (25.2 vs. 10.5 months). Those with N2A staging lived longer than other groups (24.1 vs. 12.1 months). T4 lesions portend a particularly poor prognosis; mean survival was just 7.5 months and only 1 of 28 patients (3.6%) was alive and disease-free at 2 years. Twenty-five percent of patients returned to normal function, but 75% had significant problems eating or speaking.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1986

Predatory prokaryotes: predation and primary consumption evolved in bacteria.

Two kinds of predatory bacteria have been observed and characterized by light and electron microscopy in samples from freshwater sulfurous lakes in northeastern Spain. The first bacterium, named Vampirococcus, is Gram-negative and ovoidal (0.6 micrometer wide). An anaerobic epibiont, it adheres to the surface of phototrophic bacteria (Chromatium spp.) by specific attachment structures and, as it grows and divides by fission, destroys its prey. An important in situ predatory role can be inferred for Vampirococcus from direct counts in natural samples. The second bacterium, named Daptobacter, is a Gram-negative, facultatively anaerobic straight rod (0.5 x 1.5 micrometers) with a single polar flagellum, which collides, penetrates, and grows inside the cytoplasm of its prey (several genera of Chromatiaceae). Considering also the well-known case of Bdellovibrio, a Gram-negative, aerobic curved rod that penetrates and divides in the periplasmic space of many chemotrophic Gram-negative bacteria, there are three types of predatory prokaryotes presently known (epibiotic, cytoplasmic, and periplasmic). Thus, we conclude that antagonistic relationships such as primary consumption, predation, and scavenging had already evolved in microbial ecosystems prior to the appearance of eukaryotes. Furthermore, because they represent methods by which prokaryotes can penetrate other prokaryotes in the absence of phagocytosis, these associations can be considered preadaptation for the origin of intracellular organelles.

Bdellovibrio↗
PubMed1986

Transplantation of fetal fibroblasts and correction of enzymatic deficiencies in patients with Hunter's or Hurler's disorders.

An attempt was made at correcting the specific lysosomal enzyme deficiencies in 7 children with Hunter's or Hurler's diseases by transplantation of fetal fibroblasts. In spite of pretreating the young patients with stored blood, following a procedure employed successfully to avoid rejection of kidneys from incompatible donors, the use of serum-free media for culturing the cells before being harvested and incubation of the cells with chorionic gonadotrophin, the transplantation of fetal fibroblasts was not associated with biochemical or clinical changes. None of the seven patients showed immune reactions against the transplanted cells, HLA antigens, or the missing enzymes.

Animals↗