Search PubMed⌕ Search

Biomedical subjects

R K Wilson

Publications and source records attributed to R K Wilson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Automation of dideoxynucleotide DNA sequencing reactions using a robotic workstation.

We report here a system for automation of the dideoxynucleotide DNA sequencing method. The system consists of a Beckman Biomek 1000 robotic workstation which has been modified by the addition of a thin heater/cooler block directly on the instrument table. The heater/cooler block, which is regulated by a user-specified program integrated into the Biomek software, facilitates the use of both single- and double-stranded DNA sequencing procedures. Using this system, we are able to perform 24 sets of dideoxynucleotide DNA sequencing reactions in approximately 45 min. The reactions are performed in 96-well microtiter plates, using a prepared reagent pack which includes primer, enzyme, nucleotide mixes and radioactive label. Using standard gel electrophoresis technology, we are able to resolve over 500 nucleotides per sequencing reaction in about 5 h. Currently, we are able to perform three runs of 24 samples each, with subsequent gel analysis per 8-h period. Excluding autoradiography, this represents a daily data output of 36,000 base pairs.

DNA↗
PubMed1986

Work of breathing through different sized endotracheal tubes.

The ability to breathe spontaneously through an endotracheal tube is a usual prerequisite before an intubated patient can have it removed. Other researchers have measured air flow resistance through endotracheal tubes. In this study, we evaluated work of breathing in joules per min and tension-time index while three normal volunteers breathed through different sized endotracheal tubes. Four 27.5-cm endotracheal tubes were used. Subjects breathed with a constant tidal volume of 500 ml. By increasing respiratory frequency, minute ventilation was increased from 5 to 30 L/min. As tube diameter decreased, work and the tension-time index increased. Changes were magnified at higher minute ventilations through the 6- and 7-mm endotracheal tubes, and the tension-time index critical fatigue level of 0.15 was approached or exceeded.

Equipment Design↗
PubMed1986

Palliation of bronchogenic carcinoma with 198Au implantation using the fiberoptic bronchoscope.

The majority of cases of bronchogenic carcinoma remain incurable, and many of these patients require palliation of the effects of the tumor on the airway. We have developed a technique for implanting radioactive (198Au) seeds via the fiberoptic bronchoscope. We now retrospectively review the results obtained in 111 procedures in 54 patients. Response was assessed by improvement in symptoms, chest roentgenogram, or bronchoscopic appearance. Nineteen of 29 (66 percent) patients with occluding endobronchial lesions benefitted. Twenty of 22 (91 percent) with hemoptysis improved. All six patients with tracheal lesions benefitted. Two of six (33 percent) patients with nonoccluding endobronchial lesions responded. Complications directly related to the procedure were rarely of major consequence, although a single patient had an exsanguinating hemoptysis four days following the last of multiple implantations. The simplicity, relative safety, and potential wide availability coupled with low equipment costs would suggest an increasing role for this technique in the palliation of endobronchial neoplasms.

Adult↗
PubMed1985

The complete nucleotide sequence of the Xenopus laevis mitochondrial genome.

The complete sequence of the 17,553-nucleotide Xenopus laevis mitochondrial genome has been determined. A comparison of this amphibian mitochondrial genomic sequence with those of the mammalian mitochondrial genomes reveals a similar gene order and compact genomic organization. The encoded genes for 22 tRNAs, two ribosomal RNAs, and 13 proteins (COI, COII, COIII, ATPase 6, cytochrome b, and eight additional unidentified reading frames) in the amphibian mitochondria are highly homologous to their mammalian counterparts. Although the amphibian mitochondrial genome contains a significantly larger displacement loop region than the mammalian mitochondrial genomes, there are several regions of sequence homology near the putative sites for heavy and light strand transcription initiation and heavy strand replication. The unique mitochondrial genetic code observed in the mammalian mitochondrial systems is similar to that of the X. laevis mitochondrial genome because of the presence of only 22 encoded tRNAs and the high degree of homology between the predicted protein sequences. However, the amphibian system exclusively utilizes AUG as the start codon in all 13 open reading frames and shows a preference for codons ending in U rather than ending in C. In addition, the X. laevis mitochondrial genome employs the encoded AGA stop codon once and the UAA stop codon three times and requires polyadenylation to provide the nine other UAA stop codons. These observations suggest that the mechanisms of replication, transcription, processing, and translation in mitochondria are highly conserved throughout higher vertebrates.

Animals↗
PubMed1985

Structure and localization of genes encoding aberrant and normal epidermal growth factor receptor RNAs from A431 human carcinoma cells.

A431 cells have an amplification of the epidermal growth factor (EGF) receptor gene, the cellular homolog of the v-erb B oncogene, and overproduce an aberrant 2.9-kilobase RNA that encodes a portion of the EGF receptor. A cDNA (pE15) for the aberrant RNA was cloned, sequenced, and used to analyze genomic DNA blots from A431 and normal cells. These data indicate that the aberrant RNA is created by a gene rearrangement within chromosome 7, resulting in a fusion of the 5' portion of the EGF receptor gene to an unidentified region of genomic DNA. The unidentified sequences are amplified to about the same degree (20- to 30-fold) as the EGF receptor sequences. In situ hybridization to chromosomes from normal cells and A431 cells show that both the EGF receptor gene and the unidentified DNA are localized to the p14-p12 region of chromosome 7. By using cDNA fragments to probe DNA blots from mouse-A431 somatic cell hybrids, the rearranged receptor gene was shown to be associated with translocation chromosome M4.

Amino Acid Sequence↗
PubMed1984

Pulmonary melanoma. Primary vs metastatic.

We report one of the few cases of apparently primary pulmonary melanomas documented by both clinical and autopsy examination. The possibility of spontaneous regression of a melanoma primary in another site after metastasis has occurred may explain some of these cases.

Aged↗
PubMed1983

DNA sequence of the Xenopus laevis mitochondrial heavy and light strand replication origins and flanking tRNA genes.

We have determined the primary structure of the two regions of the Xenopus laevis mitochondrial genome which encompass the origins of heavy (H) and light (L) strand replication. The first segment, which consists of 2398 nucleotides, contains the displacement loop (D-loop), the tRNA genes for threonine, proline and phenylalanine, the origin of H-strand replication, and the promoters of H- and L-strand transcription. The second segment, which consists of 447 nucleotides, contains the L-strand replication origin flanked by the tRNA genes for tryptophan, alanine, asparagine, cysteine, and tyrosine. A comparison of the sequences of the Xenopus laevis mitochondrial L-strand replication origin region and the eight tRNA genes with their counterparts from the mammalian mitochondrial genomes reveals that these regions are quite homologous, while its D-loop region shows only slight homology with those of the mammalian mitochondrial genomes.

Amino Acids↗
PubMed1982

Alteration of in vitro immunoglobulin secretion by amosite asbestos.

We investigated the in vitro effects of amosite asbestos on immunoglobulin (Ig) secretion by human peripheral blood mononuclear leukocytes (MNL). Concentrations of 100 to 300 micrograms/ml of amosite asbestos reduced the number of Ig-secreting cells recovered from 6-day cultures of unstimulated MNL or MNL stimulated with Epstein Barr virus. By contrast, the Ig secretory response to pokeweed mitogen was enhanced by 10 to 100 micrograms/ml concentrations of amosite asbestos; however, amosite asbestos no longer enhanced the response to pokeweed mitogen when MNL were first partially depleted of monocytes (to less than 2%) esterase-positive cells remaining). These results indicate that amosite asbestos has multiple effects on the cells involved in Ig secretion: 1) amosite asbestos inhibits unstimulated B cell function; 2) amosite asbestos inhibits the function of B cells stimulated with the direct B cell activator Epstein Barr virus; and 3) amosite asbestos may alter regulator monocyte function allowing enhanced Ig secretion in the presence of monocyte-dependent B cell triggers such as pokeweed mitogen.

Antibody Formation↗
PubMed1980

Asbestos body phagocytosis by human free alveolar macrophages.

Phagocytosis of asbestos bodies by human free alveolar macrophages (FAMs) was documented employing light microscopy. This process was more carefully studied utilizing scanning electron microscopy (SEM) which demonstrated morphological and surface membrane changes in FAMs following phagocytosis of asbestos bodies. FAM viability was also evaluated following 24--72-h incubation of cells with asbestos bodies at a final concentration of 250 micrograms/ml. Slight, but significant, cytotoxicity was observed following the initial 24-h culture period (P = 0.032, paired, 2-tailed t-test). No further cytotoxicity was observed, however, when cells were further incubated for 48-h and 72-h intervals (P greater than 0.05 in all instances). These studies demonstrate asbestos bodies are readily phagocytized by cultured FAMs, and are only slightly cytotoxic to these human lung cells.

Adult↗
PubMed1979

Amantadine aerosol in humans.

Seven well volunteers and three patients with a naturally occurring influenza A/USSR/77 (H1N1)-like infection were given amantadine by small-particle aerosol with a Collison generator modified for this purpose. Inhalation periods for the volunteers were increased on consecutive weekends from 15 min to 1 h, 4 h, 9 h, and 2 consecutive days of 6 h each. The particle size was 1.2-micrometer mass median diameter, and the concentration of inhaled aerosol ranged from 47 to 75 microgram/liter. Estimates of retained doses in 9 h were 74 to 149 mg. About two-thirds of the dose was recovered in the urine. Pulmonary function studies did not vary significantly from base-line values and were within a normal range for five of seven volunteers. Two volunteers with a moderate reduction in mid-maximal flow before exposure had a total of three episodes of coughing and wheezing associated with moderate reductions in mid-maximal flow values. These episodes cleared spontaneously or improved promptly after isoproterenol therapy. The patients with influenza tolerated the treatment well and recovered promptly.

Adult↗
PubMed1979

Effects of chronic amorphous silica exposure on sequential pulmonary function.

To assess clincial effects of precipitated amorphous silica (PAS), the authors reviewed serial spirograms, respiratory questionnaires, and chest radiographs of 165 workers exposed for a mean of 8.6 years. Monthly exposure was graded on a 1 to 4 scale and a "cumulative exposure index" (CEI) calculated for each worker from the sum of measured exposure. A "mean exposure index" (MEI) was calculated by dividing the CEI by total months exposed. Sputum production and dyspnea were inversely correlated with CEI, while cough and dyspnea correlated with mean pack-years of smoking but not PAS exposure. Linear regression analysis of yearly change of all pulmonary function variables (FVC, FEV1, FEV1/FVC, FEF25-75) showed no correlation with either the dose of PAS (CEI) or total years of exposure. Among 44 workers with a mean exposure time of 18 years (range 10-35 years), yearly decline of FVC and FEV1 were similar to the overall group. Of 143 workers with serial radiographs and exposure to only PAS, none had radiographic pneumoconiosis. Respiratory symptoms in PAS workers correlate with smoking but not with PAS exposure, while serial pulmonary function values and chest radiographs are not adversely affected by long-term exposure.

Adult↗