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Biomedical subjects

J D Anderson

Publications and source records attributed to J D Anderson.

At least 19 recordsLinked to original sources
PubMed1992

Primary pulmonary neoplasm in a horse.

A 16-year-old Thoroughbred gelding was evaluated for respiratory disease and found to have a primary lung tumor on postmortem examination. A tentative antemortem diagnosis was made on the basis of results of radiography and cytologic examination of a needle aspirate guided by ultrasonography. A histologic diagnosis of bronchioalveolar adenocarcinoma was made. Thoracic neoplasia is rare in horses. The most frequently reported primary pulmonary tumor is the granular cell tumor.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1992

Tentoxin sensitivity of chloroplasts determined by codon 83 of beta subunit of proton-ATPase.

Tentoxin is a naturally occurring phytotoxic peptide that causes seedling chlorosis and arrests growth in sensitive plants and algae. In vitro, it inhibits activity of the beta subunit of the plastid proton-adenosine triphosphatase (ATPase) from sensitive species. Plastid atpB genes from six closely related, tentoxin-sensitive or -resistant Nicotiana species differ at codon 83, according to their response to the toxin: glutamate correlated with resistance and aspartate correlated with sensitivity. The genetic relevance of this site was confirmed in Chlamydomonas reinhardtii by chloroplast transformation. The alga, normally tentoxin-resistant, was rendered tentoxin-sensitive by mutagenesis of its plastid atpB gene at codon 83. Codon 83 may represent a critical site on the beta subunit that does not compete with nucleotide binding or other catalytic activities.

Adenosine Triphosphate↗
PubMed1992

Enteral feeding in the critically injured patient.

Metabolic support is an integral component in the care of the critically injured patient. When hypermetabolism occurs, there are increases in energy demands along with changes in substrate utilization. This article reviews the prospective randomized clinical trials that were undertaken at Denver General Hospital over the past decade that address both the timing of nutritional support and the route of administration in this critically injured population. Also discussed is a review of a meta-analysis that attests to the feasibility of early postoperative enteral feeding with the possibility of decreased septic morbidity in high-risk surgical patients. With the clinical knowledge gained from these trials, an algorithm for nutritional intervention was developed that represents our current standard of practice.

Clinical Protocols↗
PubMed1991

Synthesis and antiviral activity of certain guanosine analogues in the thiazolo[4,5-d]pyrimidine ring system.

Several sugar-modified nucleoside derivatives of the purine analogue 5-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7-dione (1) were synthesized. Phosphorylation of 1 using POCl3 resulted in 5'-monophosphate 2, which was subsequently converted to 3',5'-cyclic phosphate 3, by reported methods. 5'-Sulfamoyl derivative 4 was synthesized by treatment of the 2,3-O-isopropylidene derivative of 1 with chlorosulfonamide followed by acid deprotection. Compounds 5-7, the 5'-deoxy, the tri-O-acetyl, and the 2'-deoxy derivatives of 1, respectively, were synthesized by glycosylation of 5-aminothiazolo[4,5-d]pyrimidine-2,7-dione, the aglycon of 1, with the appropriate sugar moieties, utilizing the Vorbruggen procedure. Oxidative cleavage of the C2'-C3' bond in 1 followed by reduction with sodium borohydride led to "seco" analogue 8. Nucleosides 2-8 were evaluated for antiviral activity in vivo against the Semliki Forest virus. The activity of compounds 2, 5, and 7 were similar to that of 1. Cyclic phosphate 3 was toxic at the high dose and weakly active at the lower dose. Compounds 4, 6, and 8 were inactive in this system.

Animals↗
PubMed1991

Comparison of self-instruction methods for teaching diagnostic testing.

In a randomized controlled trial, self-teaching booklets and computer media were evaluated for teaching diagnostic testing to dental students as a foundation for further development of clinical decision making skills. Effectiveness was assessed by pre- and post-tests. Reliability of these test instruments was examined by analyzing the pre- and post-test scores of 49 first year dental students who received no instruction. Forty-one second year dental students were exposed to clinical epidemiological principles applied to endodontic diagnosis through either self-teaching booklets or computer media. No statistically significant difference was found between the mean test scores of the students through self-teaching booklets and computer media. Although first and second year students showed a statistically significant improvement between the pre-test and post-test, the improvement in the second year class was greater. An addendum was later made to the main trial to compare the self-teaching booklet to the traditional lecture format in teaching endodontic diagnosis. Seventy-one third year dental students were exposed to these same materials through either a lecture or the self-teaching booklet and then similarly tested. There was no significant difference between the self-teaching booklet and traditional lecture for the third year students.

Computer-Assisted Instruction↗
PubMed1990

Thiazolo[4,5-d]pyrimidine nucleosides. The synthesis of certain 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidines as potential immunotherapeutic agents.

Novel analogues of the naturally occurring purine nucleosides were synthesized in the thiazolo[4,5-d]pyrimidine ring system to determine the immunomodulatory effects of insertion of a sulfur atom in place of nitrogen at position 7 of the purine ring. In particular, 5-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7(3H,6H) -dione (7, guanosine analogue), 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,5,7(3H,4H,6H) trione (8, xanthosine analogue), 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione (10, inosine analogue), and 7-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidin-2(3H)-one (32, adenosine analogue) were prepared, as well as the 8-mercaptoguanosine (14) and 6-mercaptoguanosine (17) analogues. Single-crystal X-ray studies confirmed the structural assignment of 17 and 32 as having the beta-configuration with the site of glycosylation at N3. The nucleosides were evaluated for their ability to potentiate various murine immune functions in direct comparison to the known active agents 8-bromoguanosine (1), 8-mercaptoguanosine (2), and 7-methyl-8-oxoguanosine (3). Two of the guanosine analogues, 7 and 14, were found to exhibit significant immunoactivity relative to the positive control compounds (1-3), while the adenosine, inosine, xanthosine, and 6-mercaptoguanosine analogues were devoid of activity. Compound 7 exhibited greater immunoactivity than any of the other guanosine analogues and derivatives in all test systems. Specifically, 7 was shown to be about twice as potent as 3 in the murine spleen cell mitogenicity assay. In addition, treatment with 7 produced about a 4-fold increase in natural killer cell cytotoxicity, while treatment with 3 afforded a 3-fold increase over controls. Finally, 7 provided excellent protection (92% survivors compared to 0% for placebo controls) against Semliki Forest virus in mice. Induction of interferon may account for the major mode of action of these guanosine analogues.

Adenosine↗
PubMed1990

Guanosine analogues. Synthesis of nucleosides of certain 3-substituted 6-aminopyrazolo[3,4-d]pyrimidin-4(5H)-ones as potential immunotherapeutic agents.

Several guanosine analogues were synthesized in the pyrazolo[3,4-d]pyrimidine ring system with various substituents at the 3-position. The new analogues prepared here include the CH3 (2-amino-3-methyl-1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidin-4 (5H)-one, 13a), the phenyl (2-amino-3-phenyl-1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidin-4 (5H)-one, 13b), and the NH2 (3,6-diamino-1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidin-4(5H)- one, 17) substituted derivatives. These new agents, as well as several other 3-substituted derivatives including H, Br, OCH3, COOH, and oxo, were evaluated for their ability to potentiate certain murine immune functions relative to the known active agent 5-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7(3H,6H) -dione (4, 7-thia-8-oxoguanosine). The biological evaluation included the (1) ex vivo determination of increased natural killer cell function and (2) in vivo antiviral protection against a lethal challenge of Semliki Forest virus. The 3-unsubstituted (5a) and the 3-bromo (5c) derivatives were found to be the most active immunopotentiators in this series.

Adjuvants, Immunologic↗
PubMed1990

Monofilament nylon filters for preventing dracunculiasis: Durability and copepod retention after long term field use in Pakistan.

Filtration of drinking water to remove the cyclopoid copepod intermediate hosts of guinea worm. Dracunculus medinensis, is one of the primary intervention strategies for preventing dracunculiasis. In early 1987, monofilament nylon filters with 200 microns pore size were distributed to households in selected guinea worm-infected villages in Pakistan. The filters proved popular with the villagers, although reports of "loss of filters" could diminish the community-wide effectiveness of this control measure. After 12 to 15 months of usage a sample of these filters was collected and examined for damage or impairment which would decrease their use or their capacity to retain potentially infective copepods. Although all naupliar stages and early copepodids (Stages CI-II) passed through these used filters, the larger copepodids including adults (Stages CIII-VI) were retained despite small tears in the fabric. This field trial showed that after 12 to 15 months of regular use, monofilament nylon filters of 200 microns pore size remained effective in removing copepodid stages capable of supporting development of D. medinensis larvae. Considering the ease of use, popularity and effective filtration of potentially infective copepods following prolonged field use, we recommend that monofilament filters be considered in any program of guinea worm elimination.

Animals↗
PubMed1989

Spouse adjustment to stroke: aphasic versus nonaphasic partners.

A survey of spouses of stroke patients examined the impact of stroke with and without aphasia on spouse role change, emotional problems, social adjustment, and the partner's perceived communication abilities. The results of this study support earlier findings that stroke with aphasia has a greater negative impact on the patient's spouse than does stroke without aphasia. For the spouses of aphasic patients sampled in this study, role changes represented the major adjustment made to a partner's stroke. These adjustments were greater than those experienced by the spouses of nonaphasic patients. The inability of aphasic patients to communicate well with their spouses served to make necessary role adjustments more difficult. Both spouse groups were affected to some degree by the communication problems associated with stroke, with the spouses of aphasic partners being affected the most.

Aphasia↗
PubMed1989

Low dose combined chemotherapy/radiotherapy in the management of locally advanced urethral squamous cell carcinoma.

The successful treatment of a patient with bulky squamous cell carcinoma of the urethra using low dose preoperative radiation therapy and concurrent chemotherapy is described. Dramatic rapid tumor response facilitated surgical resection of the remaining microscopic disease. This clinical behavior is remarkably similar to that seen with squamous cell carcinoma of the anal canal and esophagus when a similar regimen is used. At the latter tumor sites the successful use of combination radiotherapy and chemotherapy has reduced the morbidity of subsequent surgery, and in selected cases has obviated the need for a radical operation. Further investigation of such combination treatment is warranted for urethral carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗