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D Larsen

Publications and source records attributed to D Larsen.

At least 19 recordsLinked to original sources
PubMed2003

Estimates of conserved microsynteny among the genomes of Glycine max, Medicago truncatula and Arabidopsis thaliana.

A growing body of research indicates that microsynteny is common among dicot genomes. However, most studies focus on just one or a few genomic regions, so the extent of microsynteny across entire genomes remains poorly characterized. To estimate the level of microsynteny between Medicago truncatula (Mt) and Glycine max (soybean), and also among homoeologous segments of soybean, we used a hybridization strategy involving bacterial artificial chromosome (BAC) contigs. A Mt BAC library consisting of 30,720 clones was screened with a total of 187 soybean BAC subclones and restriction fragment length polymorphism (RFLP) probes. These probes came from 50 soybean contig groups, defined as one or more related BAC contigs anchored by the same low-copy probe. In addition, 92 whole soybean BAC clones were hybridized to filters of HindIII-digested Mt BAC DNA to identify additional cases of cross-hybridization after removal of those soybean BACs found to be repetitive in Mt. Microsynteny was inferred when at least two low-copy probes from a single soybean contig hybridized to the same Mt BAC or when a soybean BAC clone hybridized to three or more low-copy fragments from a single Mt BAC. Of the 50 soybean contig groups examined, 54% showed microsynteny to Mt. The degree of conservation among 37 groups of soybean contigs was also investigated. The results indicated substantial conservation among soybean contigs in the same group, with 86.5% of the groups showing at least some level of microsynteny. One contig group was examined in detail by a combination of physical mapping and comparative sequencing of homoeologous segments. A TBLASTX similarity search was performed between 1,085 soybean sequences on the 50 BAC contig groups and the entire Arabidopsis genome. Based on a criterion of sequence homologues <100 kb apart, each with an expected value of < or =1e-07, seven of the 50 soybean contig groups (14%) exhibited microsynteny with Arabidopsis.

Arabidopsis↗
PubMed2002

Localization of astrovirus in experimentally infected turkeys as determined by in situ hybridization.

Twenty-one 3-day-old turkey poults from British United Turkeys of America were orally inoculated with a recently characterized astrovirus, TAstV-2, isolated from turkeys with poult enteritis and mortality syndrome. At 1, 2, 3, 4, 5, 7, and 9 days postinfection (dpi), three inoculated birds were euthanatized, and tissues (intestines, spleen, bursa, and thymus) were collected immediately into 10% neutral buffered formalin. Inoculated birds were diarrheic by 3 dpi, and frothy feces persisted throughout the experimental period. Histologically, there was only slight evidence of enteric damage, which was characterized by mild epithelial necrosis, lamina propria infiltrates, minimal villus atrophy, and mild crypt hyperplasia. In situ hybridization, using a negative sense digoxigenin-labeled riboprobe to the capsid gene of TAstV-2, revealed viral RNA in intestinal epithelial cells at the basal margins of the villi, in distal small intestine, and in cecum at 2 dpi, with subsequent extension to epithelium of the large intestine and proximal small intestine (3-5 dpi). Minimal virus remained by 9 dpi.

Animals↗
PubMed2001

Soybean genomic survey: BAC-end sequences near RFLP and SSR markers.

We are building a framework physical infrastructure across the soybean genome by using SSR (simple sequence repeat) and RFLP (restriction fragment length polymorphism) markers to identify BACs (bacterial artificial chromosomes) from two soybean BAC libraries. The libraries were prepared from two genotypes, each digested with a different restriction enzyme. The BACs identified by each marker were grouped into contigs. We have obtained BAC- end sequence from BACs within each contig. The sequences were analyzed by the University of Minnesota Center for Computational Genomics and Bioinformatics using BLAST algorithms to search nucleotide and protein databases. The SSR-identified BACs had a higher percentage of significant BLAST hits than did the RFLP-identified BACs. This difference was due to a higher percentage of hits to repetitive-type sequences for the SSR-identified BACs that was offset in part, however, by a somewhat larger proportion of RFLP-identified significant hits with similarity to experimentally defined genes and soybean ESTs (expressed sequence tags). These genes represented a wide range of metabolic functions. In these analyses, only repetitive sequences from SSR-identified contigs appeared to be clustered. The BAC-end sequences also allowed us to identify microsynteny between soybean and the model plants Arabidopsis thaliana and Medicago truncatula. This map-based approach to genome sampling provides a means of assaying soybean genome structure and organization.

Algorithms↗
PubMed2000

Echocardiographic predictors of survival in low gradient aortic stenosis.

Echocardiographic predictors of long-term survival for patients with low gradient aortic stenosis who undergo aortic valve replacement have not been previously reported. This study shows that patients with larger pre- and postoperative left ventricular volumes, a lower mean preoperative aortic pressure gradient, and failure of volumes to decrease and ejection fraction to increase postoperatively may have a poor prognosis.

Adult↗
PubMed1997

MR artifacts, heat production, and ferromagnetism of Guglielmi detachable coils.

The Guglielmi detachable coil, a platinum microcoil used in the endovascular treatment of intracranial aneurysms, was studied in vitro for its MR imaging artifacts, heat production, and ferromagnetism. In addition, imaging artifacts were studied in vivo in eight patients who had undergone therapeutic placement of these coils. These devices displayed a very low level of MR artifact and no ferromagnetism or heat production. We conclude that the Guglielmi detachable coil is compatible with MR imaging in terms of both safety and image quality.

Aneurysm, Ruptured↗
PubMed1996

Distinguishing detection from identification in subliminal auditory perception: a review and critique of Merikle's study.

Assertions made by Merikle (1988) regarding audio subliminal messages were tested. Seventeen participants were presented subliminal messages embedded in a white-noise cover, and three signal-to-noise (S/N) detection ratios were examined. Participants were asked to guess message presence and message content, to determine subjective/objective thresholds. Results showed that participants were unable to identify target words presented in this audio subliminal stimulus format beyond chance levels.

Adolescent↗
PubMed1993

Implementation of practice guidelines in a clinical setting using a computerized knowledge base (Iliad).

We present the implementation of the indications for surgery for three surgical operations--cholecystectomy, cataract extraction, and knee arthroscopy--in a medical expert system, called Iliad. This implementation operates in the preauthorization service of IHC Health Plans (an insurance company in Salt Lake City) as a basis for reimbursement of services. Patient data collection forms, derived from Iliad knowledge base, were used by 13 participating surgeons to document the objective patient observations that justify the surgery and, then were faxed to IHC where a trained nurse input the data in Iliad. Iliad's decisions and reports on any deviations from guidelines are communicated back to the care provider. The study evaluates the impact of the computerized implementation on process, as measured by a questionnaire, and on outcome as measured by rate of approvals, documentation level, rate of requests, and average cost. The prospective implementation of the computerized guidelines has performed reliably, has been perceived as a preferred alternative to the old preauthorization system, and, most importantly, has enhanced significantly the level of documentation permitting evaluation and determination of appropriateness before surgery.

Arthroscopy↗
PubMed1991

Identification and characterization of a new member of the prolactin family, placental lactogen-I variant.

This report describes the identification and characterization of a new member of the placental prolactin (PRL) family, termed placental lactogen-I variant (PL-Iv). PL-Iv was isolated from medium conditioned by late gestation placental explants. Rat PL-Iv was found to be closely related to rat PL-I. Amino-terminal sequence analysis indicated that PL-Iv shared approximately 88% sequence identity with the amino terminus of PL-I. PL-Iv proteins cross-reacted with antiserum to recombinant mouse PL-I and PL-Iv mRNA hybridized with a PL-I cDNA. Multiple PL-I and PL-Iv species were present in placental cytosol. Despite the structural similarities between PL-I and PL-Iv, distinct differences were also evident. Antibodies generated to the amino-terminal 19 amino acids of PL-Iv specifically recognized PL-Iv, while failing to recognize PL-I. Secreted PL-Iv had an affinity for concanavalin A, whereas secreted PL-I lacked affinity for the lectin. PL-I was predominantly secreted as a 36-40-kDa species and PL-Iv was predominantly secreted as a 33-kDa species. Furthermore, PL-I and PL-Iv were synthesized at different times during gestation and by different cell types. PL-I was synthesized by trophoblast giant cells during the first half of gestation, while PL-Iv was predominantly synthesized by spongiotrophoblast cells during the later stages of gestation. PL-Iv was shown to stimulate the proliferation of rat Nb2 lymphoma cells, an in vitro measure of lactogenic activity. In summary, PL-Iv shares structural similarities with PL-I; however, it shows other structural differences in addition to unique cell- and temporal-specific patterns of expression in the rat chorioallantoic placenta.

Amino Acid Sequence↗
PubMed1991

Generation and characterization of antipeptide antibodies to rat cytochrome P-450 side-chain cleavage enzyme.

In this report, we describe the generation of immunologic probes to rat P-450scc. Two regions of the P-450scc amino acid sequence were identified (internal domain: amino acids 421-441; carboxy terminal domain: amino acids 509-526), chemically synthesized and used as immunogens in rabbits. Antibody production was monitored by enzyme-linked immunoassay (EIA) and Western blot analyses. Antisera were successfully generated to each of the P-450scc regions that recognized the entire 49 kDa rat P-450scc protein. Antiserum directed to the internal domain of P-450scc showed broad species crossreactivity, whereas antiserum directed to the carboxy terminal domain of P-450scc crossreacted with only rat and mouse. Both antisera were useful for Western blot and immunocytochemical analyses of rat P-450scc expression. In addition to recognizing the major 49 kDa P-450scc protein, each antiserum also recognized lower molecular weight species. Antiserum directed to the internal domain of P-450scc specifically recognized a 42 kDa species, whereas antiserum directed to the carboxy terminal domain specifically recognized an 8 kDa species. We hypothesize that the two lower molecular weight immunoreactive species are generated by proteolytic cleavage of rat P-450scc between the internal and carboxy terminal epitopes.

Adrenal Glands↗
PubMed1991

Identification and immunochemical characterization of a major placental secretory protein related to the prolactin-growth hormone family, prolactin-like protein-C.

Trophoblast cells of the rat chorioallantoic placenta synthesize and secrete a number of proteins structurally related to pituitary PRL. During the purification of one member of the placental PRL family, PRL-like protein-A (PLP-A), we identified a major contaminating protein with a similar mol wt but possessing a more acidic pI (5.9-6.1) and different immunoreactivities. After isolation by two-dimensional gel electrophoresis, the more acidic contaminating protein was electroeluted, and its N-terminal amino acid sequence was determined by gas phase sequencing. The N-terminal sequence showed considerable homology with members of the PRL family, including characteristic positioning of cysteine residues at amino acids 4 and 11. The newly identified protein species have been termed PLP-C based on their structural similarity with pituitary PRL. The protein was further characterized by the generation of specific immunological probes. Antibodies were generated to electrophoretically purified protein and to a chemically synthesized peptide representing amino acids 11-32 of its N-terminal sequence. Each antiserum specifically recognized two major species migrating at approximately 25 and 29 kDa, respectively. The 29-kDa species specifically bound to Concanavalin-A, while the 25-kDa species failed to bind to the lectin. Furthermore, the 29-kDa species could be converted to the 25-kDa species by enzymatic deglycosylation. The antisera have also been used to examine the cell- and temporal-specific patterns of expression. The immunoreactive protein species (25 and 29 kDa) were localized primarily to spongiotrophoblast cells present in the junctional zone of the chorioallantoic placenta. Expression was initiated after midgestation and increased during the remaining part of gestation. In summary, PLP-C is a major secretory protein produced by spongiotrophoblast cells during the second half of gestation.

Animals↗
PubMed1991

Color Doppler sonography of the scrotum.

Color Doppler sonography is a noninvasive, rapidly performed, and relatively inexpensive imaging technique for use in the diagnosis of scrotal pathology. Its major and proven role is in the evaluation of patients with acute scrotal pain, for which it is likely to become the primary imaging modality. Further work is needed to determine whether color Doppler is a useful diagnostic adjunct in evaluating patients with varicoceles and scrotal masses.

Doppler Effect↗
PubMed1986

Persistence of antibody and response to booster dose of Haemophilus influenzae type b polysaccharide diphtheria toxoid conjugate vaccine in infants immunized at 9 to 15 months of age.

At approximately 2 years of age, 27 infants previously immunized at 9 to 15 months of age with two doses of polyribosylribitol phosphate-diphtheria toxoid conjugate vaccine (PRP-D) and 23 infants immunized with polyribosylribitol phosphate (PRP) vaccine were given a single injection of PRP-D. Pre- and post-immunization sera were obtained. No serious local or systemic reactions were observed. The PRP-D recipients had a geometric mean anti-PRP antibody level of 4.8 micrograms/ml 1 month after the second primary injection, retained 1.2 microgram/ml 1 year later, and had a level of 71 micrograms/ml after the booster immunization. In contrast, PRP recipients had a geometric mean level of 0.083 microgram/ml 1 month after the second primary injection, retained 0.042 microgram/ml 1 year later, and after a single dose of PRP-D at approximately 2 years of age had a geometric mean level of 8.6 micrograms/ml. The significantly higher antibody response in the prior PRP-D recipients suggests the recall of immunologic memory induced by the PRP-D vaccine.

Antibodies, Bacterial↗
PubMed1984

The walk-in anergic patient. How best to assess the risk of sepsis following elective surgery.

This prospective study evaluated host resistance in a surgical population who walked into the hospital for elective surgery. Patients were stratified into Hospital Reactive (HR, n = 19) if they reacted to two or more of five recall skin test antigens and Walk-in Anergic (WA, n = 26) if they did not react to the antigens. The WA patients were slightly older (74.4 +/- 1.8 years, +/- SEM versus 66.7 +/- 2.7 p less than 0.05). Diagnosis in the HR and WA group were: tumors 13/19 versus 21/26, diverticulitis 3/19 versus 0/19, and miscellaneous 3/19 versus 5/26. Twenty-five laboratory normal controls (LN) were also studied. There were no significant differences in the following parameters between the HR and WA groups: stage of disease; hemoglobin; circulating leukocyte count; polymorphonuclear cell counts; total lymphocyte counts (both groups lower than LN, p less than 0.05), monocyte counts (both higher than LN, p less than 0.05); per cent E-rosettes and lymphocyte blastogenesis to mitogens (phytohemagglutinin, concanavalin-A) and antigens (purified protein derivative and tetanus); phagocytosis of preopsonised Staphylococcus aureus 502A, at 5, 10, and 20 minutes; alpha, beta, and gamma globulins; C3, and total hemolytic complement (CH50) levels; C-reactive protein; and ANA and DNA levels. The HR group demonstrated an increase in the rate of killing of Staphylococcus 502A at 10, 20, 40, and 80 minutes compared to the LN group but the WA group did not show this augmentation (p less than 0.001). The serum albumins were: LN = 4.46, HR = 3.98, WA = 3.43 g/dl (p less than 0.05). Degree and duration of surgery was the same in the HR and WA groups. There were no major sepsis episodes (bacteremia or proven intracavitary abscess) in the HR patients versus 25% in the WA patients (p less than 0.05). There was one death (6%, pulmonary embolus) in the HR group and 8 (40%) in the WA group (p less than 0.05). Antibiotic prophylaxis was equal but the WA patients received therapeutic antibiotics more frequently (65% versus 11% p less than 0.05). Of all the host immunocompetence tests measured in this study, the delayed type hypersensitivity skin test response and the serum albumin were variables abnormal between the survivors and those who died.

Adult↗