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Biomedical subjects

A Dee

Publications and source records attributed to A Dee.

13 recordsLinked to original sources
PubMed2006

Short communication: disinfectant containing a complex of skin conditioners.

The efficacies of 2 new teat dip formulations were tested against experimental challenge by contagious mastitis pathogens Staphylococcus aureus and Streptococcus agalactiae over a 12-wk period. Formulations contained an iodine complex (0.5 or 1.0% iodine) and skin conditioning agents (propylene glycol, polyvinylpyrridone, glycerine, lanolin, allantoin, and aloe). Percentage reduction (dipped vs. control mammary quarters) in new contagious mastitis pathogen intramammary infections for the 0.5 and 1.0% iodine dips was 65.4 and 84.5, respectively. Both dips were significantly effective in reducing new contagious intramammary infections. Teat skin scores and teat end scores varied over time but were virtually identical for both treated and control teats, for both treatments. Thus, both dips were effective in reducing new contagious mastitis infections without untoward effects on teat skin condition.

Allantoin↗
PubMed1998

Paraneoplastic pruritus and alopecia in a horse with diffuse lymphoma.

An 8-year-old castrated male Paint Horse was referred because of generalized pruritus, alopecia, and intermittent fever. Results of gross evaluation of the skin and microscopic evaluation of skin scrapings were inconclusive. Histologic examination of skin biopsy specimens revealed vasculitis. The horse had persistent hypercalcemia; therefore, lymphosarcoma was considered a possibility. Ultrasonography revealed hypoechoic nodules within the parenchyma of the spleen and liver. Results of microscopic evaluation of an aspirate from a splenic nodule were suggestive of lymphosarcoma. The condition of the horse deteriorated, and it was subsequently euthanatized. Postmortem examination revealed diffuse lymphoma. In human beings, generalized pruritus may be an indication of serious internal disease, including malignancy. Paraneoplastic pruritus is most common in patients with Hodgkin's lymphoma but can also develop in patients with non-Hodgkin's lymphoma, leukemia, or a solid neoplasm. Lymphoma should be considered in the differential diagnoses when examining horses with generalized pruritus for which another cause cannot be identified.

Alopecia↗
PubMed1992

Design and implementation of a particle concentration fluorescence method for the detection of HIV-1 protease inhibitors.

A critical step in the replicative cycle of the human immunodeficiency virus HIV-1 involves the proteolytic processing of the polyprotein products Prgag and Prgag-pol that are encoded by the gag and pol genes in the viral genome. Inhibitors of this processing step have the potential to be important therapeutic agents in the management of acquired immunodeficiency syndrome. Current assays for inhibitors of HIV-1 protease are slow, cumbersome, or susceptible to interference by test compounds. An approach to the generation of a rapid, sensitive assay for HIV-1 protease inhibitors that is devoid of interference problems is to use a capture system which allows for isolation of the products from the reaction mixture prior to signal quantitation. In this paper, we describe a novel method for the detection of HIV-1 protease inhibitors utilizing the concept of particle concentration fluorescence. Our approach involves the use of the HIV-1 protease peptide substrate Ser-Gln-Asn-Tyr-Pro-Ile-Val which has been modified to contain a biotin moiety on one side and a fluorescein reporter molecule on the other side of the scissile Tyr-Pro bond. This substrate is efficiently cleaved by the HIV-1 protease and the reaction can be readily quantitated. Known inhibitors of the protease were readily detected using this new assay. In addition, this approach is compatible with existing instrumentation in use for broad screening and is highly sensitive, accurate, and reproducible.

Amino Acid Sequence↗
PubMed1991

Purification of recombinant HIV-1 protease.

A method is described to purify recombinant HIV-1 protease from soluble extracts of Escherichia coli. The isolation involves QAE-Sepharose anion exchange chromatography, hexyl agarose hydrophobic interaction chromatography, MonoS cation exchange chromatography, and Superose 6 size exclusion chromatography. Approximately 100 micrograms of protease was obtained from 18 g E. coli paste. The protein was judged to be homogeneous due to the presence of a single band on a silver-stained SDS polyacrylamide gel.

Chromatography, Agarose↗
PubMed1990

Expression and secretion of a functional scorpion insecticidal toxin in cultured mouse cells.

We have expressed a synthetic gene encoding the insecticidal neurotoxin of scorpion Androctonus australis (AaIT) in NIH/3T3 mouse fibroblast cells under the transcriptional control of a murine retroviral long terminal repeat. The secretion of the toxin into the culture medium was directed by the signal peptide of human interleukin-2. The recombinant AaIT produced was selectively toxic to yellow-fever mosquito larvae and harmless to mice.

Aedes↗
PubMed1990

Involvement of DNA topoisomerase II in the selective resistance of a mammalian cell mutant to DNA minor groove ligands: ligand-induced DNA-protein crosslinking and responses to topoisomerase poisons.

A mutant murine cell line has previously been reported to be resistant to the AT-specific DNA minor groove ligand 2',5'-bi-1H-benzimidazole, 2',(4-ethoxyphenyl)-5-(4-methyl-1-piperazinyl), trichloride (Ho33342), due to an enhanced capacity to remove ligand molecules from cellular DNA via a pathway which can be blocked by DNA topoisomerase poisons. We have studied the relationship between ligand resistance and DNA topoisomerase II activity. The cross-sensitivity patterns of the mutant were examined for covalently (anthramycin) and non-covalently (distamycin A) binding minor groove ligands, and DNA intercalating [adriamycin, mitoxantrone and 4'-(9-acridinylamino)methanesulphon-m-anisidide (mAMSA)] and non-intercalating (VP16-213) topoisomerase II poisons. The mutant was cross-resistant to distamycin A alone. The mutant showed no abnormality in: (i) the in vitro decatenation activity of topoisomerase II, (ii) VP16-213 or mAMSA induced protein-DNA cross-linking activities in nuclear extracts, (iii) 'cleavable complex' generation (or DNA strand scisson) in intact cells exposed to topoisomerase poisons. Ho33342 and the topoisomerase II inhibitor novobiocin were found to disrupt both the in vitro binding of nuclear extracted proteins, from mutant and parental cells, to plasmid DNA and the formation of drug-induced cleavable complexes in vitro. Unexpectedly, Ho33342 induced significant levels of DNA-protein crosslinking in both parental and mutant cells. We conclude that: (i) resistance of the mutant is limited to non-covalently binding minor groove ligands, (ii) Ho33342 can block the trapping of DNA topoisomerase II by enzyme poisons in vitro, (iii) Ho33342 can induce a novel form of DNA-protein cross-link in intact cells, and (iv) the resistance of the mutant is not dependent upon some abnormality in topoisomerase II function.

Amsacrine↗
PubMed1989

Structural characterization of the bovine CYP17 (17 alpha-hydroxylase) gene.

The complete exonic and partial intronic sequence of the bovine CYP17 (P45017 alpha) gene has been determined. The gene contains eight exons with exon/intron boundaries which are identical to those determined previously for the human CYP17 gene. The site of initiation of transcription of this gene is located within a 6-base sequence 52 bp from the initiation of translation. Considerable sequence homology (58.7%) is found when approximately 500 bp of the 5'-flanking sequences of the bovine and human CYP17 genes are compared. A computer-based search of this region of bovine CYP17 for consensus sequences associated with binding of transcription factors (i.e., GR, PR, CREB/ATF, AP1, AP2, AP3, AP4, AP5, OTF, CTF/NF1, SP1) shows only the consensus CREB/ATF sequence TGACGT which is also found to be at approximately the same position in the human CYP17 gene. In bovine adrenal cortex, transcription of the CYP17 gene is regulated by the peptide hormone adrenocorticotropin via cAMP. Whether the consensus CREB/ATF sequence is associated with the cAMP-mediated transcription of the CYP17 gene remains to be elucidated.

Adrenal Cortex↗
PubMed1986

Bovine steroid 21-hydroxylase: regulation of biosynthesis.

A recombinant cDNA clone, PBC21-1, specific for bovine steroid 21-hydroxylase cytochrome P-450 (P-450C21) was identified in a bovine adrenocortical cDNA library, and this identity was confirmed by nucleotide sequencing which revealed significant amino acid homology (77%) with human P-450C21 cDNA. The pBC21-1 insert is 1.7 kilobases in length and includes a 1128 base pair region that encodes the C-terminal 376 amino acids of bovine P-450C21 as well as 535 base pairs of 3'-untranslated sequence. A novel feature of this insert is a 20 base pair intervening sequence near the 5' end, apparently the result of an aberrant splicing event. Northern blot analysis reveals that bovine P-450C21 is encoded by two transcripts, 2.3 and 2.0 kilobases in length which are detected in adrenal cortical RNA. Bovine liver, heart, kidney, and corpus luteum do not contain detectable P-450C21 transcripts. Regulation of P-450C21 gene expression by adrenocorticotropin was investigated with pBC21-1 and bovine adrenocortical cells in primary, monolayer culture. Treatment with ACTH or analogues of cAMP increases the steady-state levels of P-450C21 RNA in such cell cultures. In vitro transcription run-on assays suggest that this increase is, at least in part, due to the enhanced transcriptional activity of the P-450C21 gene.

Adrenal Cortex↗
PubMed1986

The insulin-like growth factor, somatomedin C, induces the synthesis of cholesterol side-chain cleavage cytochrome P-450 and adrenodoxin in ovarian cells.

The actions of insulin and somatomedin C (insulin-like growth factor I) on cholesterol side-chain cleavage activity and the synthesis of cytochrome P-450scc and adrenodoxin were investigated in primary cultures of swine ovarian (granulosa) cells. Nanomolar concentrations of pure human somatomedin C stimulated biosynthesis of progesterone and 20 alpha-hydroxypregn-4-en-3-one. Moreover, in the presence of exogenous sterol substrate for cholesterol side-chain cleavage, somatomedin C significantly enhanced pregnenolone biosynthesis in a time- and dose-dependent manner. This augmentation of functional cholesterol side-chain cleavage activity was accompanied by a dose-dependent (2-16-fold) increase in [35S]methionine incorporation into specific immunoprecipitable cytochrome P-450scc and adrenodoxin. Micromolar concentrations of insulin (but not proinsulin or desoctapeptide) also induced synthesis of cholesterol side-chain cleavage constituents by 4-7-fold. These results demonstrate that an insulin-like growth factor, somatomedin C, exerts discrete differentiating effects on ovarian cells characterized by increased synthesis of immunospecific cytochrome P-450scc and adrenodoxin. Thus, we infer that somatomedin C may serve a critical role in the differentiation of steroidogenic cells in the mammalian ovary.

Adrenodoxin↗
PubMed1985

Regulation of synthesis and activity of bovine adrenocortical NADPH-cytochrome P-450 reductase by ACTH.

Primary, monolayer cultures of bovine adrenocortical cells have been utilized to demonstrate that ACTH regulates the synthesis and thus the activity of NADPH-cytochrome P-450 reductase. The temporal pattern of induction correlates well with that previously reported for cytochromes P-45017 alpha and P-450 C21, microsomal steroid hydroxylases serviced by P-450 reductase. Results of in vitro translation studies suggest that ACTH regulates P-450 reductase synthesis at the transcriptional level and show that the adrenocortical enzyme is synthesized as the mature form. The action of ACTH to induce P-450 reductase synthesis in the adrenal cortex can be mimicked by dibutyryl cAMP, but not by phenobarbital which induces P-450 reductase synthesis in liver.

Adrenal Cortex↗
PubMed1984

Induction of synthesis of mitochondrial steroidogenic enzymes of bovine adrenocortical cells by analogs of cyclic AMP.

The long term action of cyclic AMP analogs to stimulate the synthesis of cytochromes P-450scc, P-45011 beta, and adrenodoxin has been studied utilizing confluent monolayers of adult bovine adrenocortical cells maintained for periods of time up to 72 h in the absence or presence of dibutyryl cyclic AMP (1 mM), 8-bromo cyclic AMP (1 mM), or ACTH (adrenocorticotropin) (10(-6) M). The synthesis of these proteins was examined by radiolabeling cellular proteins with [35S]methionine or else by translating RNA extracted from such cells in a cell-free system in the presence of [35S]methionine. In each case, the protein under study was immunoprecipitated utilizing specific antisera, or IgG fractions prepared from such antisera. ACTH and both analogs of cyclic AMP caused an increase in the synthesis of cytochrome P-450scc which reached a maximum 36-48 h after addition, and then declined. On the other hand, butyric acid (1 mM) had no effect on the synthesis of cytochrome P-450scc. Cytochrome P-450scc activity measured as pregnenolone production by both intact cells or isolated mitochondria from such cells was increased following incubation of cells with either dibutyryl cyclic AMP or ACTH. The binding of rabbit anti-cytochrome P-450scc IgG was also increased in cells incubated with dibutyryl cyclic AMP or ACTH as estimated by immunofluorescence microscopy using fluorescein-tagged anti-rabbit IgG. Furthermore, dibutyryl cyclic AMP and ACTH both increased the synthesis of adrenodoxin and of cytochrome P-45011 beta, as well as the activity of 11 beta-hydroxylase. In addition, ACTH stimulated the secretion of cyclic AMP in a time- and concentration-dependent fashion. Thus, it is concluded that analogs of cyclic AMP can mimic the long term actions of ACTH to induce the synthesis of steroidogenic enzymes, and that this action of ACTH is likely mediated by cyclic AMP.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMedDate not supplied

Speech and language development in a parent-infant total communication program.

In the program described, the use of total communication (TC) did not impede speech development in preschool deaf children. Evidence indicates that sign language facilitated the young hearing-impaired child's acquisition of communicative oral speech. Exposure to sign language combined with speech enhanced the meaningfulness of residual hearing and lipreading. Milestones in sign language acquisition paralleled the milestones of spoken language. Young hearing-impaired TC children appeared to learn and express more language at an earlier age than is typical of orally trained hearing-impaired children. This implies that their cognition may not be as severely inhibited because their language acquisition is less severely delayed. This should have favorable consequences for later educational and social development. The families In the TC program were able to normalize their child-rearing activities and relationships.

Child Language↗