Biomedical subjects

R S Nelson

Publications and source records attributed to R S Nelson.

At least 37 records · Page 2Linked to original sources

PubMed1995

Comparison of modified PhadezymRAST, ImmunoCAP, and serial dilution titration skin testing by receiver operating curve analysis.

Improved technology in in vitro tests for allergen-specific immunoglobulin E has led to increased efficiency and faster turnaround times. ImmunoCAP (Pharmacia Diagnostics, Clayton, N.C.) is an in vitro-specific immunoglobulin E test that uses a three-dimensional cellulose solid allergen phase, which allows quick results in 6 hours. In comparison, modified Phadezym-RAST (Pharmacia Diagnostics) uses a two-dimensional solid phase, and results take 3 days to obtain. This study compares the sensitivity and specificity of CAP with that of modified RAST in the detection of specific immunoglobulin E, and it assesses the correlation of the individual class scores of CAP and modified RAST with end points obtained from skin-dilutional end-point titration. The reproducibility of CAP was also assessed. Patients evaluated at the University of Chicago Allergy Clinic who had a history and physical examination consistent with immunoglobulin E-mediated allergy and in whom skin testing was clinically indicated as part of their allergy management, were asked to donate some blood for simultaneous in vitro testing by PhadezymRAST and ImmunoCAP. Testing was performed in batches. Random samples from the CAP batches were chosen for duplicate runs under conditions blinded to the technician. Receiver operating curve analysis was used for comparison of the sensitivity and specificity of RAST vs. that of CAP. We used Pearson product-moment correlation coefficients to compare the correlation of RAST and CAP classes with the end points from skin testing. Our results indicate that the sensitivity and specificity of RAST and CAP are similar, that the classes of these two tests correlate well with the end points from skin testing, and that duplicate samples of CAP also correlate well.

Adolescent↗

PubMed1995

A long thin electrode is equivalent to a short thick electrode for defibrillation in the right ventricle.

We hypothesized that a long thin right ventricular (RV) electrode would have equivalent defibrillation threshold (DFT) performance to a short thick electrode with approximately the same surface area. This could lead to thinner transvenous lead systems, which would be easier to implant. A thin (5.1 French) lead was compared to a standard control (10.7 French). The thin lead had an 8-cm RV electrode length with a surface area of 4.26 cm2. The standard lead had a RV electrode length of 3.7 cm and a surface area of 4.12 cm2. A 140-mu French capacitor 65%/65% tilt biphasic defibrillation shock was delivered between the RV electrode and a 14-cm2 subcutaneous patch. DFTs were determined following 10 seconds of fibrillation in 11 dogs by a triple determination averaging technique. The thin lead had a lower resistance (77.1 +/- 27.4 omega vs 88.9 +/- 30.3 omega, P < 0.001) than did the thick lead. There was no significant difference in stored energy DFTs (9.9 +/- 2.5 vs 10.3 +/- 2.7, P = 0.098 2-sided, P = 0.049 1- sided). This was in spite of the fact that the long thin lead had a portion of its RV coil extending above the tricuspid valve and, thus, not contributing efficiently to the ventricular gradients in the small dog heart. We conclude that a long thin right ventricular electrode and a standard short thick electrode had equivalent defibrillation performance. This preliminary result should be confirmed in clinical studies as it could lead to significantly thinner transvenous lead systems.

Animals↗

PubMed1995

Ceftiofur distribution in serum and milk from clinically normal cows and cows with experimental Escherichia coli-induced mastitis.

Eight Holstein cows, 4 inoculated intracisternally in 1 quarter of the mammary gland with Escherichia coli and 4 noninfected controls, were administered ceftiofur sodium (3 mg/kg of body weight, IV, q 12 hours) for 24 hours, beginning at 14 hours after inoculation of infected cows. All challenge-exposed cows became infected, with mean +/- SEM peak log10 bacterial concentration in milk of 5.03 +/- 0.69 colony-forming units/ml. The infection resulted in systemic signs (mean peak rectal temperature, 41.5 +/- 0.3 C; anorexia; signs of depression) and local inflammation (mean peak albumin concentration in milk, 7.89 +/- 1.71 mg/ml). Ceftiofur was detectable in milk from all challenge-exposed cows, compared with only 1 of 4 noninfected cows, and the mean period after inoculation that ceftiofur was detectable in milk was longer (P < 0.05) in infected (147.7 +/- 27.5 hours) than noninfected cows (1.3 +/- 1.3 hours). However, maximal ceftiofur concentration attained in milk for all cows was 0.28 microgram/ml, and was 0.20 microgram/ml or less for all but 2 milk samples collected for 10 days after challenge exposure. Mean serum concentration of ceftiofur peaked at 1.0 +/- 0.3 microgram/ml and 0.7 +/- 0.1 microgram/ml for infected and noninfected cows, respectively. After each ceftiofur dose, mean peak and trough concentrations of ceftiofur in serum did not differ between groups; however, concentration of ceftiofur in serum was higher at 7 hours after each dose in noninfected cows, suggesting more rapid clearance of the drug in infected cows.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Nucleotide sequence and genome organization of peanut stripe potyvirus.

A blotch isolate of peanut stripe virus (PStV) was cloned, sequenced and compared with other full-length potyvirus sequences. The viral genome was 10059 nucleotides (nt) in length excluding the poly(A) tail. Two potential AUG start codons were identified in the 5' non-translated region. Analysis of in vitro translation products from transcripts containing the first 600 nt of the PStV genome indicated that the first AUG (nt 134 to 136) was preferred over the second AUG (nt 146 to 148) for initiation of translation. Within the single large open reading frame, eight processed proteins were predicted. In general, motifs conserved in other potyviral sequences were also found in the PStV genome. The presence of a 6K protein between the P3 and CI proteins was predicted. An altered amino acid motif, from FI(V)VRG to FMIIRG, within the carboxyl terminus of the P1 protein, separates the PStV sequence from the majority of potyvirus sequences. Based on comparisons with available full-length potyvirus genome sequences, PStV was found to be most closely related to soybean mosaic virus.

Amino Acid Sequence↗

PubMed1994

Rapid clinical diagnosis of pulmonary abnormalities in HIV-seropositive patients by auscultatory percussion.

A prospective, blinded study of pulmonary findings in hospitalized patients with HIV infection compared auscultatory percussion (AusP) with conventional percussion (ConP) and conventional auscultation (ConA) using chest radiographs as the gold standard. Sixty-three patients had chest radiographs and were examined by one to three examiners. Seventy of the 126 lungs had radiographic abnormalities (55.6 percent). Auscultatory percussion proved to be the most sensitive of all techniques for each examiner (range, 51.0 to 69.6 percent) for detecting radiographic abnormalities and also had higher likelihood ratios for two of the three examiners; AusP also had the highest likelihood ratio pooled across examiners. Of the 166 abnormal results of lung examinations, the combination of AusP and ConA detected 31 more abnormalities than ConP and ConA combined, with 14 of these being diagnosed with Pneumocystis carinii pneumonia. No abnormalities were detected by ConP that were not detected by AusP. These findings suggest that AusP, a rapid clinical maneuver, is more sensitive and specific than ConA and ConP in determining pulmonary abnormalities in HIV-infected inpatients.

Adult↗

PubMed1994

Enhanced recovery of transformants of Agrobacterium tumefaciens after freeze-thaw transformation and drug selection.

Freeze-thaw transformation provides a simple and rapid method to transform Agrobacterium tumefaciens directly with plasmid DNA. Competent A. tumefaciens cells of strains LBA4404, GV3850 and EHA101 were transformed with four to nine plasmids differing in size, size of insert and in some cases sensitivity to antibiotics. A threefold to fourfold increase in transformed colonies per microgram of DNA was obtained by freezing cells with liquid nitrogen vs. dry ice/ethanol. Freezing cells in liquid nitrogen followed by incubation of transformed cells in a low concentration of appropriate antibiotics prior to plating resulted in a ninefold increase in colonies obtained compared with the procedure of freezing cells in dry ice/ethanol without the incubation period in the low concentration of antibiotics prior to plating. Restriction fragments of the expected sizes from the plasmids indicated that the procedural modifications did not cause apparent recombinations in the region of the inserts.

Agrobacterium tumefaciens↗

PubMed1993

Cloning of the capsid protein gene from a blotch isolate of peanut stripe virus.

The 3' terminal 1,367 nucleotides (nts) of a blotch isolate of the potyvirus, peanut stripe virus (PStV), were cloned and sequenced. This region included the 861 nts (287 amino acids) of the PStV capsid protein (CP). The amino acid sequence of the predicted proteinase cleavage site was identified. This region shared limited homology with other potyvirus proteinase cleavage sites. The viral CP gene sequence was followed by 254 nucleotides of 3' nontranslated sequence and a poly-A tail. Based on computer modeling, the 3' nontranslated region could form two lengthy stem-loop structures and two pseudoknot structures. Subclones containing the coding sequences of the CP (amino acids 1-287, 17-287, 17-113 and 106-287) were constructed and expressed in Escherichia coli. These polypeptides were detected using polyclonal antibodies in Western blots.

Amino Acid Sequence↗

PubMed1990

Local and systemic spread of tobacco mosaic virus in transgenic tobacco.

Expression of a chimeric gene encoding the coat protein (CP) of tobacco mosaic virus (TMV) in transgenic tobacco plants confers resistance to infection by TMV. We investigated the spread of TMV within the inoculated leaf and throughout the plant following inoculation. Plants that expressed the CP gene [CP(+)] and those that did not [CP(-)] accumulated equivalent amounts of virus in the inoculated leaves after inoculation with TMV-RNA, but the CP(+) plants showed a delay in the development of systemic symptoms and reduced virus accumulation in the upper leaves. Tissue printing experiments demonstrated that if TMV infection became systemic, spread of virus occurred in the CP(+) plants essentially as it occurred in the CP(-) plants although at a reduced rate. Through a series of grafting experiments, we showed that stem tissue with a leaf attached taken from CP(+) plants prevented the systemic spread of virus. Stem tissue without a leaf had no effect on TMV spread. All of these findings indicate that protection against systemic spread in CP(+) plants is caused by one or more mechanisms that, in correlation with the protection against initial infection upon inoculation, result in a phenotype of resistance to TMV.

Capsid↗

PubMed1987

Expression of alfalfa mosaic virus coat protein gene confers cross-protection in transgenic tobacco and tomato plants.

A chimeric gene encoding the alfalfa mosaic virus (AlMV) coat protein was constructed and introduced into tobacco and tomato plants using Ti plasmid-derived plant transformation vectors. The progeny of the self-fertilized transgenic plants were significantly delayed in symptom development and in some cases completely escaped infection after inoculated with AlMV. The inoculated leaves of the transgenic plants had significantly reduced numbers of lesions and accumulated substantially lower amounts of coat protein due to virus replication than the control plants. These results show that high level expression of the chimeric viral coat protein gene confers protection against AlMV, which differs from other plant viruses in morphology, genome structure, gene expression strategy and early steps in viral replication. Based on our results with AlMV and those reported earlier for tobacco mosaic virus, it appears that genetically engineered cross-protection may be a general method for preventing viral disease in plants.

Journal Article↗

PubMed1986

Delay of disease development in transgenic plants that express the tobacco mosaic virus coat protein gene.

A chimeric gene containing a cloned cDNA of the coat protein (CP) gene of tobacco mosaic virus (TMV) was introduced into tobacco cells on a Ti plasmid of Agrobacterium tumefaciens from which tumor inducing genes had been removed. Plants regenerated from transformed cells expressed TMV mRNA and CP as a nuclear trait. Seedlings from self-fertilized transgenic plants were inoculated with TMV and observed for development of disease symptoms. The seedlings that expressed the CP gene were delayed in symptom development and 10 to 60 percent of the transgenic plants failed to develop symptoms for the duration of the experiments. Increasing the concentration of TMV in the inoculum shortened the delay in appearance of symptoms. The results of these experiments indicate that plants can be genetically transformed for resistance to virus disease development.

DNA↗

PubMed1986

Effects of flurbiprofen and aspirin on the gastric and duodenal mucosa. An endoscopic comparison.

A single-blind, randomized endoscopic tolerance study was conducted to compare daily doses of flurbiprofen (Ansaid, Upjohn) at 100, 150, and 200 mg per day with 2,600 mg of aspirin per day. Ten normal volunteers were enrolled in each of the flurbiprofen groups, and five were enrolled in the aspirin group. Analysis of the mean gastric mucosal injury scores obtained on day eight revealed statistically significant lower mean scores (p = 0.05) in the 100-mg and 150-mg flurbiprofen treatment groups when compared with the 200-mg flurbiprofen group and the aspirin group. No significant differences were found between any of the treatment groups in duodenal mucosal injury scores. Mean scores for gastric mucosal injury in the three groups receiving flurbiprofen showed a definite dose relationship. The aspirin-treated subjects had significantly decreased uric acid levels (p = 0.006) and a significantly higher incidence of tinnitus (p = 0.04) compared with the flurbiprofen treatment groups. There was a poor correlation between subjective symptomatology and endoscopic pathologic findings.

Adult↗

PubMed1986

Nitrate Reductases from Wild-Type and nr(1)-Mutant Soybean (Glycine max [L.] Merr.) Leaves : II. Partial Activity, Inhibitor, and Complementation Analyses.

Soybean (Glycine max [L.] Merr.) leaves have been shown to contain three forms of nitrate reductase (NR). Two of the forms, which are present in leaves of wild-type (cv. Williams) plants grown in the absence of NO(3) (-), are termed constitutive and designated c(1)NR and c(2)NR. The third form, which is present in NO(3) (-)-grown mutant (nr(1)) plants lacking the constitutive forms, is termed inducible and designated iNR. Samples of c(1)NR, c(2)NR, and iNR obtained from appropriately treated plants were analyzed for the presence of partial activities, response to inhibitors, and ability to complement a barley NR which lacks the molybdenum cofactor (MoCo) but is otherwise active.The three forms were similar to most assimilatory NR enzymes in that they (a) exhibited NADH-cytochrome c reductase, reduced flavin mononucleotide-NR, and reduced methyl viologen-NR partial activities; (b) were inhibited by p-hydroxymercuribenzoate at the site of initial electron transport through each enzyme; (c) were more inhibited by CN(-) in their reduced enzyme state as compared with their oxidized state; and (d) complemented a MoCo-defective NR (e.g. contained cofactors with characteristics similar to the MoCo found in barley NR and commercial xanthine oxidase). However, among themselves, they showed dissimilarities in their response to treatment with HCO(3) (-) and CN(-), and in their absolute ability to complement the barley NR. The site of effect for these treatments was the terminal cofactor-containing portion of each enzyme. This indicated that, although a terminal cofactor (presumably a MoCo) was present in each form, structural or conformational differences existed in the terminal cofactor-protein complex of each form.

Journal Article↗

PubMed1986

Effect of acetaminophen on human gastric mucosal injury caused by ibuprofen.

Acetaminophen has been proposed as an agent which protects the gastric mucosa against damage induced by aspirin and other non-steroidal anti-inflammatory agents. In order to evaluate this proposal further, 45 normal human volunteers were divided into three groups (n = 15); group one received ibuprofen 2400 mg daily (600 mg qid); group two received acetaminophen 3900 mg daily (975 mg qid) and group three received both drugs at the same dosages. There was no significant difference in the mucosal injury scores noted at endoscopy between the ibuprofen and the ibuprofen-acetaminophen group. The acetaminophen group had virtually no observed mucosal injury and this was statistically significant in comparison with the other groups (p less than 0.01). We conclude that contrary to previously reported studies using single doses of aspirin, acetaminophen failed to decrease the mucosal injury seen with ibuprofen when given for a period of seven days in combination with acetaminophen.

Acetaminophen↗

PubMed1985

Nitrate Reductases from Wild-Type and nr(1)-Mutant Soybean (Glycine max [L.] Merr.) Leaves : I. Purification, Kinetics, and Physical Properties.

NADH:nitrate reductase (EC 1.6.6.1) and NAD(P)H:nitrate reductase (EC 1.6.6.2) were purified from wild-type soybean (Glycine max [L.] Merr., cv Williams) and nr(1)-mutant soybean plants. Purification included Blue Sepharose- and hydroxylapatite-column chromatography using acetone powders from fully expanded unifoliolate leaves as the enzyme source.Two forms of constitutive nitrate reductase were sequentially eluted with NADPH and NADH from Blue Sepharose loaded with extract from wild-type plants grown on urea as sole nitrogen source. The form eluted with NADPH was designated c(1)NR, and the form eluted with NADH was designated c(2)NR. Nitrate-grown nr(1) mutant soybean plants yielded a NADH:nitrate reductase (designated iNR) when Blue Sepharose columns were eluted with NADH; NADPH failed to elute any NR form from Blue Sepharose loaded with this extract. Both c(1)NR and c(2)NR had similar pH optima of 6.5, sedimentation behavior (s(20,w) of 5.5-6.0), and electrophoretic mobility. However, c(1)NR was more active with NADPH than with NADH, while c(2)NR preferred NADH as electron donor. Apparent Michaelis constants for nitrate were 5 millimolar (c(1)NR) and 0.19 millimolar (c(2)NR). The iNR from the mutant had a pH optimum of 7.5, s(20,w) of 7.6, and was less mobile on polyacrylamide gels than c(1)NR and c(2)NR. The iNR preferred NADH over NADPH and had an apparent Michaelis constant of 0.13 millimolar for nitrate.Thus, wild-type soybean contains two forms of constitutive nitrate reductase, both differing in their physical properties from nitrate reductases common in higher plants. The inducible nitrate reductase form present in soybeans, however, appears to be similar to most substrateinduced nitrate reductases found in higher plants.

Journal Article↗

PubMed1985

Mouse peritoneal macrophages plated on mannan- and horseradish peroxidase-coated substrates lose the ability to phagocytose by their Fc receptors.

Ligand-conjugated substrates were used to study mouse macrophage receptor-ligand interactions. Both resident and thioglycollate-elicited macrophages plated on substrates conjugated with mannans and horseradish peroxidase (HRP), ligands for the Man/GlcNAc receptor, lost their ability to phagocytose zymosan. In addition, these macrophages also lost their ability to phagocytose IgG-coated erythrocytes (E(IgG] via their Fc receptors (FcR). The abrogation of Fc receptor-mediated phagocytosis occurred as early as 4 hr after macrophage plating on HRP-coated substrates and was dependent on the amount of HRP conjugated to the substrate. Macrophages plated on those substrates showed a 70% reduction in E(IgG) binding and the same decrease (approximately 35%) in binding of 125I-labeled Fab fragment of monoclonal anti-IgG2b FcR antibody as macrophages plated on dinitrophenyl-anti-dinitrophenyl IgG immune complexes. We interpret these results as showing that modulation of macrophage mannose/GlcNAc receptors induces modulation of FcR.

Animals↗

PubMed1985

Ethanol, aspirin, ibuprofen, and the gastroduodenal mucosa: an endoscopic assessment.

The effect on the gastroduodenal mucosa of alcohol combined either with aspirin or ibuprofen was studied in 60 normal volunteers. The volunteers were divided into six groups comprised of 10 subjects receiving ibuprofen, placebo, or aspirin with or without alcohol. Medications consisted of 1) three 325-mg aspirin tablets, or three identical placebo tablets, 2) one 600-mg ibuprofen tablet, and 3), three ounces of 100 proof vodka diluted in 6 ounces of orange juice, or alcohol placebo made by diluting 3 ounces of water in orange juice. All subjects received 4 doses over a 24-hr period and underwent endoscopic examination the following morning. The gastroduodenal mucosa was graded according to a 0 to 4 + scale. Aspirin caused considerably greater duodenal and gastric damage than did either ibuprofen or placebo. The addition of alcohol to all drugs increased the damage seen in the stomach but not to a significant degree; this effect was slightly more pronounced with ibuprofen than with placebo or aspirin and approached significance (0.1 greater than p greater than 0.05). These results are compatible with alcohol being a mild damaging agent or a potentiating agent for damage from other drugs.

Adult↗

PubMed1984

Stages IE and IIE non-Hodgkin's lymphomas of the stomach. Comparison of treatment modalities.

Seventy-nine patients with Stages IE and IIE non-Hodgkin's lymphomas of the stomach were treated between 1953 and 1980. The histopathologic classification was as follows: diffuse large cell, 61 (of which 23 were immunoblastic sarcomas [plasmacytoid]); diffuse well-differentiated lymphocytic, 6; diffuse mixed, 1; undifferentiated non-Burkitt's, 1; nodular, 9; and unclassifiable, 1. Thirty-five patients had Stage IE disease and 44 had Stage IIE. Treatment modalities included surgery, radiotherapy, chemotherapy, and combinations thereof. Sixty-six patients had a laparotomy for diagnosis and/or management. Of these, only 42 had a gastrectomy. The stomach was considered to be unresectable in the other 24 patients. There were 5 postoperative deaths among 31 patients who had a laparotomy or gastrectomy at our institution. The overall 5-year actuarial survival was 56%; the disease-free survival was 54%. For patients with Stage IE disease the survival was 76%, and for those with Stage IIE, 42%. Promising results were obtained in 13 patients who were treated on a multimodality program consisting of four cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus bleomycin (Bleo), which was alternated with involved field radiotherapy. All 13 patients had no evidence of disease as of this report. Only one patient had a relapse (Waldeyer's ring), and he was salvaged with radiotherapy. Six of these 13 were diagnosed by endoscopic biopsy and did not have a laparotomy, 3 were found to have unresectable disease at laparotomy, and 4 had a resection. Biopsy with the flexible fiberscope and treatment with CHOP-Bleo and radiotherapy can avoid the morbidity and mortality of gastrectomy.

Adult↗

PubMed1984

Digital subtraction angiography with an Isocon camera system: clinical applications.

A new imaging system for digital subtraction angiography (DSA) was evaluated in 30 clinical studies. The image receptor is a 25 X 25 cm, 12 par gadolinium oxysulfate rare-earth screen whose light output is focused to a low-light-level Isocon camera. The video signal is digitized and processed by an image-array processor containing 31 512 X 512 memories 8 bits deep. In most patients, intraarterial DSA studies were done in conjunction with conventional arteriography. In these arterial studies, images adequate to make a specific diagnosis were obtained using half the radiation dose and half the amount of contrast material needed for conventional angiography. In eight intravenous studies performed either to identify renal artery stenosis or for evaluation of congenital heart anomalies, the images were diagnostic but objectionably noisy.

Angiography↗