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L M Glode

Publications and source records attributed to L M Glode.

At least 37 records · Page 2Linked to original sources
PubMed1990

Sequence of cDNA for rat cystathionine gamma-lyase and comparison of deduced amino acid sequence with related Escherichia coli enzymes.

A cDNA clone for cystathionine gamma-lyase was isolated from a rat cDNA library in lambda gt11 by screening with a monospecific antiserum. The identity of this clone, containing 600 bp proximal to the 3'-end of the gene, was confirmed by positive hybridization selection. Northern-blot hybridization showed the expected higher abundance of the corresponding mRNA in liver than in brain. Two further cDNA clones from a plasmid pcD library were isolated by colony hybridization with the first clone and were found to contain inserts of 1600 and 1850 bp. One of these was confirmed as encoding cystathionine gamma-lyase by hybridization with two independent pools of oligodeoxynucleotides corresponding to partial amino acid sequence information for cystathionine gamma-lyase. The other clone (estimated to represent all but 8% of the 5'-end of the mRNA) was sequenced and its deduced amino acid sequence showed similarity to those of the Escherichia coli enzymes cystathionine beta-lyase and cystathionine gamma-synthase throughout its length, especially to that of the latter.

Amino Acid Sequence↗
PubMed1989

Production of diphtheria toxin CRM228 in B. subtilis.

The gene coding for a nontoxic diphtheria toxin (DT), tox228, was isolated from lysogenic Corynebacterium diphtheriae and cloned into pBR322. A mature form of the tox228 gene, lacking its signal sequence, was expressed in Bacillus subtilis using a B. amyloliquefaciens alpha-amylase secretion vector. To test the possibility of producing partially deleted DT molecules, which could be used for cell-directed toxin conjugates, a truncated form lacking 151 amino acids from the C-terminus of the DT was generated by oligonucleotide mutagenesis. Both the truncated and intact DT were efficiently secreted into the culture medium. During prolonged cultivation, the truncated form was less stable than the intact DT molecule.

Amino Acid Sequence↗
PubMed1988

Cystathionine metabolism in neuroblastoma.

Cystathioninuria is a frequent and highly specific marker of neuroblastoma, but the etiology of this abnormality has not been well studied. To investigate this phenomenon, we analyzed 27 human neuroblastoma tissue specimens for the presence of cystathionine synthase and cystathionase. Levels of cystathionine synthase varied from undetectable to 622 pmol/mg protein, but no specimen had cystathionase measurable by rocket radioimmunoassay or catalytic assay. In addition, we assayed neuroblastoma cell lines exposed to a variety of differentiating agents: butyric acid, dimethyl sulfoxide, serum-free medium, or sodium citrate to induce differentiation. In each case we were unable to demonstrate cystathionase induction. These data are consistent with the hypothesis that neuroblastomas have a biochemical block in the transsulfuration enzymes at the level of cystathionase and that expression of cystathionine synthase in the absence of cystathionase may account for the presence of cystathioninuria in patients with neuroblastoma.

Cell Differentiation↗
PubMed1987

Genetic ablation: targeted expression of a toxin gene causes microphthalmia in transgenic mice.

Lineage-specific regulatory elements can be used to direct expression of a variety of genes to specific tissues in transgenic mice. If the hybrid constructs contain a gene encoding a cytotoxic gene product, then genetic ablation of a specific cell lineage can be achieved. We have generated six transgenic mice by introducing into fertilized eggs the mouse gamma 2-crystallin promoter fused to the coding region of the diphtheria toxin A-chain gene. Three of these mice and all the transgenic offspring analyzed were microphthalmic. The lenses of these mice displayed considerable heterogeneity: some were almost normal morphologically but reduced in size, whereas others were grossly aberrant and deficient in nuclear fiber cells. These studies indicate that programmed ablation of specific cell types can be stably transmitted through the germ line.

Animals↗
PubMed1987

Long-term suppression of luteinizing hormone, follicle-stimulating hormone and testosterone by daily administration of leuprolide.

The chronic effect of long-term injections of leuprolide on the hypothalamic, pituitary and gonadal axes have been studied in men with advanced prostatic cancer. The possibility of transient acute changes in luteinizing hormone, follicle-stimulating hormone and testosterone after each daily injection was studied in 31 patients treated for more than 1 year. No evidence of escape from daily 1.0 mg. doses was noted. No pituitary responsiveness was observed at any time point examined. Thus, daily administration of 1.0 mg. leuprolide acetate subcutaneously produces durable, complete suppression of gonadotropins and testosterone for prolonged periods.

Follicle Stimulating Hormone↗
PubMed1987

Cloning, sequence determination, and expression in transfected cells of the coding sequence for the tox 176 attenuated diphtheria toxin A chain.

DNA including the coding sequence for the A chain of the mutant diphtheria toxin tox 176 was cloned. The cloned mature A-chain coding sequence showed a G-to-A transition at nucleotide 383 as the only difference from the wild-type sequence. This resulted in replacement of the glycine at position 128 by aspartic acid in the predicted amino acid sequence. A eucaryotic cell expression plasmid, pTH1-176, was constructed in which the tox 176 A-chain coding sequence was attached to a truncated metallothionein promoter. The toxicity of this construct, compared with that of the corresponding wild-type diphtheria toxin A-chain plasmid, pTH1, was assessed after transfection into the human 293 cell line by an indirect transient expression assay (I. H. Maxwell, F. Maxwell, and L. M. Glode, Cancer Res. 46:4660-4664, 1986). For the same effect, 15- to 30-fold more pTH1-176 than pTH1 was required, a result consistent with previous in vitro estimates of the diminished activity of the tox 176 A chain. Controlled expression of the cloned tox 176 A-chain coding sequence may provide a means of eliminating specific cell populations in an organism, for which purpose the wild-type diphtheria toxin A chain might prove too toxic.

Amino Acid Sequence↗
PubMed1986

Biological implications of androgen dependent changes in proton-NMR relaxation times in rat ventral prostate.

The present studies were conducted in rat ventral prostate to determine if proton nuclear magnetic resonance (1H-NMR) might be a useful tool to monitor physiologic changes in an androgen-dependent target tissue after ablation and reconstitution. Ventral prostate mass and blood flow (86RbCl distribution) decreased markedly after castration. Although prostate water content was not affected by androgen ablation, 1H-NMR spin-lattice (T1) and spin-spin (T2) relaxation times determined on excised prostate tissue were reduced by 10% and 50%, respectively. Testosterone propionate (Tp) reconstitution resulted in a prompt but transient increase in total water content, marked increases in prostate blood flow, and regrowth of the gland. 1H-NMR studies indicated that although T1 lengthening after Tp was temporally related to changes in prostate water content, T1's remained prolonged after total prostate water content returned to control levels. Increased Gd-DTPA-dimeg modification of prostate T1 by Gadolinium-DTPA-dimethyl glucamine in androgen reconstituted rats implied that prostate extracellular water volumes were markedly increased during intervals of increased T1. Recovery of prostate T2 relaxation times after Tp was delayed with respect to changes in T1, water content, and prostate blood flow, but was temporally correlated with increase in prostate dry mass. Studies to assess Gd-DTPA-dimeg T2 modification showed that prostate T2 changes after androgen depletion and replacement reflected spin-spin relaxation of water protons outside the in vivo Gd-DTPA-dimeg distribution volume. The results from these studies indicate that 1H-NMR and paramagnetic probes may be useful to noninvasively monitor biologically relevant changes in cellular and extracellular water in androgen-dependent target tissues during hormonal manipulations.

Androgens↗
PubMed1986

Phase I clinical trial of intracarotid bis-chloroethylnitrosourea (BCNU) and 2' dioxy-5-fluorouridine (FUDR) in malignant astrocytomas.

Systemic chemotherapy has been of limited benefit in the treatment of intracranial neoplasms, due, in part, to the inability to deliver effective drug doses to the neoplasm without systemic toxicity. We have completed a clinical trial of intracarotid BCNU and FUDR using an implantable pump in patients with unilateral malignant astrocytomas (Grade III and IV) in the hope of obtaining better tumor control with less systemic toxicity. Six patients had in-dwelling catheters placed in the internal carotid artery attached to a percutaneous refillable pump (Infusaid 400). The treatment program consisted of bolus BCNU 400 mg every 6 weeks and FUDR by continuous infusion at dosages ranging from 0.5 mg/24 h to 2.5 mg/24 h. The maximum tolerable dose of FUDR was 1 mg/24 h with ipsilateral mucositis and conjunctivitis being dose limiting factors. Flow studies demonstrated significant perfusion of the ipsilateral eye and surrounding face secondary to ophthalmic artery collaterals. No patient had systemic toxicity and the lowest WBC encountered was 2 400 with normal differential and platelets.

Aged↗
PubMed1986

The biology of gonadotropin-releasing hormone and its analogs.

Gonadotropin-releasing hormone (GnRH) is one of the hormones involved in the complex hypothalamic-pituitary-gonadal axis which regulates the release of testosterone from the testes or estrogen from the ovaries. The development of GnRH analogs has helped elucidate the mechanism of action of the natural hormone, and provided possible new ways to treat hormonally related conditions including hormone-dependent cancers, precocious puberty, and endometriosis. The effectiveness of GnRH agonists in clinical use lies in their ability, with long-term administration, to suppress sex-hormone production. GnRH antagonists may eventually replace agonists because they are able to reduce hormone levels without the initial, temporary rise caused by agonists.

Antineoplastic Agents↗
PubMed1986

Recovery of blood and bone marrow stem cells following intense chemotherapy and autologous bone marrow transplantation.

Sixteen patients with advanced (stage III) malignant melanoma were treated with escalating doses of intravenous BCNU and melphalan starting at 400 and 35 mg/m2, respectively, and escalating to 1,000 and 110 mg/m2, respectively, combined with autologous marrow transplantation. The duration of granulocytopenia and time to granulocyte recovery was similar in all groups regardless of chemotherapy dose. Platelet recovery was delayed in patients receiving the highest doses of chemotherapy. This study showed that bone marrow colony-forming units in culture took as long as 6 months to recover. This was adequate to bring peripheral blood counts to normal but not to pretreatment levels. These studies indicate that autologous bone marrow transplantation is beneficial in enhancing short-term recovery, but may not be beneficial in the long-term hematopoietic recovery.

Agranulocytosis↗
PubMed1986

Regulated expression of a diphtheria toxin A-chain gene transfected into human cells: possible strategy for inducing cancer cell suicide.

As an alternative to directing plant or bacterial toxins to surface receptors, we are investigating the possibility of killing tumor cells by the expression of an exogenously introduced toxin gene (i.e., cell suicide). Tissue-specific gene regulatory elements might thus be exploited to achieve selective killing. To assess the feasibility of such an approach, we have transfected human cells (HeLa, B-lymphoblastoid, and 293 cells) with plasmids containing the diphtheria toxin A-chain (DT-A) coding sequence. The presence of the DT-A sequence lowered the level of transient expression of chloramphenicol acetyltransferase from a cotransfected plasmid, pSV2cat. This expression level in B-cells was further diminished by the inclusion of an immunoglobulin enhancer in the DT-A plasmid. In cotransfection experiments with a DT-A plasmid lacking an enhancer, chloramphenicol acetyltransferase expression was much more strongly inhibited in 293 cells (which express adenovirus E1A and E1B products) than in the other cell types; furthermore, the presence of the DT-A sequence eliminated recovery of G418-resistant 293 cell transformants after transfection with a plasmid containing the neo selectable marker. These results suggest that cell-specific regulatory mechanisms can be exploited to achieve selective cell killing by expression of an introduced toxin gene.

Acetyltransferases↗
PubMed1985

LHRH.

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Gonadotropin-Releasing Hormone↗
PubMed1985

Clinical effects of gonadotropin-releasing hormone analogue in metastatic carcinoma of prostate.

Leuprolide is a new, potent analogue of gonadotropin-releasing hormone which, after an initial transient stimulation, causes a profound suppression of serum gonadotropins and testosterone. One hundred eighteen patients with advanced carcinoma of the prostate have undergone treatment with leuprolide in a multi-institutional trial. Minimal evidence of objective response was seen in patients who had failed prior endocrine therapy with orchiectomy or estrogens. In patients without previous hormonal treatment, leuprolide induced an objective disease response (72%) comparable to alternative primary endocrine therapy. Considering the lack of significant side effects seen with long-term GnRH agonists, compounds such as leuprolide may prove to be the preferred initial endocrine therapy for selected patients with metastatic carcinoma of the prostate.

Adenocarcinoma↗