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Biomedical subjects

C Anderson

Publications and source records attributed to C Anderson.

At least 325 records · Page 18Linked to original sources

Nuclear DNA density of parathyroid lesions.

Nuclear DNA density analysis was carried out on six normal control human parathyroid glands and forty-six pathological lesions of human parathyroid tissue. The pathological glands had originally been classified as twenty hyperplasias, twenty-one adenomas, and five carcinomas in accordance with clinical-pathological information. Specimens had been obtained through the Surgical Pathology Department of the University Hospital, London, in the form of either imprints from the cut surface of a lesion, or as cell separation samples from a paraffin block. Nuclear DNA ploidy analysis of the normal glands showed, as expected, a diploid cell population. Sixty-one percent of nuclei of the carcinomas were above 2C, extending to 7C. There was a significant difference in nuclear DNA content between normal and benign tissue versus tissue classified as carcinoma. No significant difference in nuclear DNA ploidy could be established between the benign adenoma and hyperplasia tissue; however, marked significant DNA ploidy differences were found between tissue from the latter two and carcinoma. DNA ploidy from cell image analysis using Feulgen's reaction can be useful in establishing a differential diagnosis between carcinoma and benign lesions.

Adenocarcinoma↗

Pericranial healing and the temporalis myo-osseous flap in the rabbit model.

The purpose of this animal study was to determine the rate of revascularization of a temporalis myo-osseous (TMO) flap after pericranial elevation. In 24 rabbits, the right pericranium was raised in entirety through a bicoronal flap at the first operation. The pericranium was then reapproximated in situ. The pericranium was allowed to heal for 1 to 28 days before the second operation. At the second operation, through the same bicoronal flap, right and left temporalis myo-osseous flaps were raised. The left temporalis myo-osseous flap served as a control. Revascularization and viability of the temporalis myo-osseous flaps were studied by using technetium bone scans, india ink injection studies, and histologic study. Results demonstrated that 4 days following pericranial elevation, the temporalis myo-osseous flap is viable and revascularized by the pericranium. Immediate bone scanning and india ink injection showed patent pericranial circulation to the osseous portion of the temporalis myo-osseous flap at 4 days. Histologic study confirmed the viability of the temporalis myo-osseous flap. In conclusion, after pericranial elevation, pericranial healing and revascularization were complete at 4 days. This allowed a viable temporalis myo-osseous flap to be raised successfully at this time.

Animals↗

Biodegradation of polyhydroxyalkanoates.

Degradation of poly(3-hydroxybutyrate) and copolymers with 3-hydroxyvaleric acid was investigated in natural environments, and the microorganisms involved were isolated and identified. The influence of abiotic and biotic factors on the degradation is discussed.

Bacteria↗

Cloning and expression of a transferrin-binding protein from Actinobacillus pleuropneumoniae.

An expression library was constructed from Actinobacillus pleuropneumoniae serotype 7. Escherichia coli transformants expressing recombinant proteins were identified by immunoscreening with porcine convalescent serum. One transformant expressing a 60-kDa protein (60K protein) in aggregated form was identified. Serum raised against the recombinant protein recognized a polypeptide with an indistinguishable electrophoretic mobility in the A. pleuropneumoniae wild type after iron-restricted growth only. The recombinant protein bound transferrin after blotting onto nitrocellulose. Using a competitive enzyme-linked immunosorbent assay (ELISA), the specificity of this binding for the amino-terminal half of iron-saturated porcine transferrin was established. Also, the 60K wild-type protein bound hemin as assessed by hemin-agarose chromatography. Hemin could inhibit transferrin binding of the recombinant protein in the competitive ELISA, whereas hemoglobin and synthetic iron chelators failed to do so. Southern blot analysis of several other A. pleuropneumoniae strains indicated that highly homologous sequence is present in eight of eight isolates of serotype 7 and in some isolates of serotypes 2, 3, and 4.

Actinobacillus pleuropneumoniae↗

Characterization of two genes encoding distinct transferrin-binding proteins in different Actinobacillus pleuropneumoniae isolates.

The gene encoding the Actinobacillus pleuropneumoniae serotype 1 transferrin-binding protein (tfbA) was cloned, and the carboxy-terminal 70% of the protein was expressed as an aggregate protein in Escherichia coli. The nucleotide sequences of the tfbA genes from A. pleuropneumoniae serotypes 7 (G.-F. Gerlach, C. Anderson, A. A. Potter, S. Klashinsky, and P. J. Willson, Infect. Immun. 60:892-898, 1992) and 1 were determined, and a comparison revealed that they had 65% sequence identity. The deduced amino acid sequences showed a sequence agreement of 55%, and both proteins possessed a lipoprotein-like signal sequence. The serotype 1 TfbA protein had a predicted molecular mass of 65 kDa, compared with 60 kDa for the serotype 7 TfbA protein, and both proteins were immunologically distinct as assessed in a competitive enzyme-linked immunosorbent assay. Southern hybridization and Western blot (immunoblot) analysis of the 13 A. pleuropneumoniae type strains revealed that serotypes 2, 3, 4, 8, 9, 10, and 11 encode and express a TfbA protein highly homologous to that of A. pleuropneumoniae serotype 7 whereas the TfbA proteins and the encoding genes of serotypes 6 and 12 were highly homologous to that found in A. pleuropneumoniae serotype 1. The tfbA genes of A. pleuropneumoniae serotypes 5A and 5B were recognized, under medium-stringency hybridization conditions, by the A. pleuropneumoniae serotype 1-derived tfbA probe, and the respective proteins were weakly reactive with the antibody raised against the A. pleuropneumoniae serotype 7 TfbA protein.

Actinobacillus pleuropneumoniae↗

In vivo microdialysis estimation of histamine in human skin.

Microdialysis, a new bioanalytical sampling technique, enables the measurement of substances in the extracellular space. This study investigates the use of the technique in the in vivo measurement of histamine levels in human skin. Microdialysis probes are equipped at the tip with a semipermeable polycarbonate membrane which permits the passive diffusion of substances. 16 probes were inserted, via a guide, into the skin of the ventral forearm of 8 patients or volunteers. The probe was perfused at a flow of 5 microliters/min, with samples being collected at intervals of 10 min and analysed by RIA technique. The mean histamine level in the first 10-min sample following probe insertion was 39.4 nM. The mean histamine value fell with successive 10-min samples (8.8, 4.6, 2.3 nM). An equilibration period of 40 min following probe insertion is suggested for histamine studies, where provocation of the skin is to be performed. Microdialysis appears to be a promising new tool for quantitative and chronological studies of cutaneous inflammatory mediators.

Dialysis↗

Prevention of diabetes in nonobese diabetic mice by dendritic cell transfer.

The purpose of this study was to determine the effect of dendritic cell (DC) transfers on the incidence of diabetes in female nonobese diabetic (NOD) mice. Groups of 4-wk-old NOD female mice were given a single foot pad of DCs (70-90% purity) isolated from the draining lymph nodes (LN) of the pancreas (PLN), the cervical LNs, or the axillary/inguinal LNs. In addition, other groups of NOD mice received purified spleen DCs, purified PLN T cells (the major contaminating population in DC preparations), or the injection vehicle PBS. All groups were monitored for diabetes for one year. Significant protection from diabetes was observed in NOD mice receiving greater than 1 x 10(4) PLN DCs in comparison to mice receiving other DCs populations, PLN T cells, or PBS (P less than 0.05). The pancreata of NOD mice that received PLN DCs demonstrated significantly lower levels of lymphocytic infiltration in the islets that age-sex matched nondiabetic female NOD control mice (P less than 0.05). LN cells from nondiabetic NOD mice that received PLN DC protected irradiated female recipients from the adoptive transfer of diabetes to a greater degree than LN cells from age and sex matched nondiabetic female NOD mice that did not receive PLN DC transfers at 36 d (P = 0.014) and at 1 yr (P = 0.0015) after transfer. These data suggest that the PLN DC transfers are able to modulate autoimmunity and limit diabetes expression in the NOD mouse. PLN DCs transfers may regulate autoimmunity by the induction of regulatory cells.

Animals↗

Drug discovery and development in the pharmaceutical industry.

The discovery and development of new anticancer drugs is a complex and largely empirical process. New compounds can be discovered by screening, modification of existing compounds, rational drug design, and serendipitous basic research observations. Selection of compounds for clinical trials depends on assays of uncertain predictive value. In the pharmaceutical industry, priorities for development of potentially active entities are set and available resources allocated based on the availability and cost of supplies, patent status, potential spectrum of activity, ability to meet regulatory requirements, and market assessments. Competition for resources also occurs from noncancer drugs, eg, cardiovascular agents. Clinical development (testing and approval for commercial distribution) requires close attention to the requirements of national regulatory agencies such as the United States Food and Drug Administration. The arbitrary nature by which compounds with antitumor potential are chosen for development means that some that would be useful never reach clinical trial and others are never made generally available. This article reviews the decision making process in the pharmaceutical industry by which compounds are identified and selected for clinical trial, the regulations in the United States that govern such trials, and what is required to have the drug approved for commercial distribution.

Animals↗

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Humans↗