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J Schultz

Publications and source records attributed to J Schultz.

At least 37 records · Page 2Linked to original sources
PubMed2000

Do consumers use information to choose a health-care provider system?

This study examines the use of information by employees in the Buyers Health Care Action Group, a purchasing coalition of large employers in Minneapolis. BHCAG employers contract directly with multiple health-care provider systems and attempt to inform employees about those choices. Shortly after the close of the 1998 open-enrollment period, a survey of 927 BHCAG employees with single-coverage health insurance was conducted. Seventy-six percent of the employees relied on information from their employer when selecting their current care system. Use of information from the employer was positively related to education and years of residence in the Twin Cities. Previous experience with doctors and hospitals in the care system also was a common information source. Older and low-income workers were more likely to use information from advertisements. The survey results suggest that employers can predict which information sources their employees will use.

Adult↗
PubMed2000

Ablation of noninducible idiopathic left ventricular tachycardia using a noncontact map acquired from a premature complex with tachycardia morphology.

We describe use of a novel noncontact system to permit mapping in a noninducible patient from a single premature ventricular complex with tachycardia morphology, thus guiding successful ablation after two previously failed conventional efforts. The instantaneous global electroanatomic map demonstrated fascicular macroreentry. Subsequent to ablation at an inferolateral site, there has been no clinical recurrence despite difficult arrhythmia control preprocedure. This case demonstrated that noncontact mapping can be used to create a potential map to guide successful ablation from a single premature ventricular complex in a patient with idiopathic left ventricular tachycardia that became noninducible at electrophysiological study.

Adult↗
PubMed2000

Update on antiviral DNA vaccine research (1998-2000).

DNA vaccines can induce protective cellular and humoral immune responses and have therefore been used during the last decade to develop vaccines against a variety of different pathogens. Because current antiviral vaccines predominantly generate humoral immunity, DNA immunization may be especially useful to provide long-term protection against viral diseases that also require cellular immunity (e.g. HIV). A significant number of articles published in the field of DNA vaccines are dealing with viral diseases, reflecting the need for better and alternative vaccination strategies against viruses. The success of DNA immunization depends on a variety of parameters (e.g. type of antigen, method of application and usage of adjuvants). Therefore, different strategies have been explored to modulate the induced immune response with respect to the requirements necessary to protect against a specific pathogen (e.g. induction of mucosal or cell-mediated immunity). The following article provides an update on different aspects of antiviral DNA vaccine research that have previously been reviewed by others.

Animals↗
PubMed2000

DNA vaccination against La Crosse virus.

For the development of effective conventional vaccines or DNA vaccines against viruses, the availability of suitable animal models is an essential prerequisite. For many recently emerging zoonotic viruses, suitable animal models are still missing. We have established a novel small animal model for DNA vaccines using mice lacking a functional interferon-alpha/beta receptor (IFNAR-1). IFNAR-1-deficient mice are highly susceptible to many different viruses despite their ability to mount a normal humoral and cellular immune response. Taking advantage of this animal model, we show that mice can be completely protected from lethal challenge with a single injection of plasmid DNA encoding the viral envelope proteins G1 and G2. By contrast, vaccination with a plasmid encoding the internal nucleocapsid protein N had little effect. In an effort to enhance the protective immune response to N we assessed the efficacy of vaccination with plasmid DNA encoding N in combination with a plasmid encoding the cytokine IL-12 as adjuvant. IL-12 enhanced the survival of mice following viral challenge, but the effect was independent of N indicating the involvement of components of the innate immune system such as NK cells.

Animals↗
PubMed2000

Effects of intermittent UVA exposure on cultured lens epithelial cells.

PURPOSE: This paper addresses the question of whether a single non-lethal dose of UVA radiation or the same dose divided three daily one-third doses have like or unlike effects on the growth and the catalase activity of cultured rabbit epithelial (RLE) and immortalized human epithelial (HLE) cells. METHODS: Non-confluent cultured RLE and HLE cells were used to study the effects of UVA radiation on their growth. The effects of three doses of 3 J/cm(2) given one day apart on cell growth (i.e. live cell number) over a three day period were compared with those of a single 9 J/cm(2 ) exposure. Estimation of live cell numbers was done 24 hrs after each exposure by counting trypan blue exclusive cells using a hemocytometer. Confluent cultures of RLE cells were used to study the effects of UVA radiation on their catalase activity. The effects of three doses of 1.25 J/cm(2) each given one day apart on catalase activity (breakdown of H( 2) O( 2) measured spectro-photometrically at 240 nm) were compared with that of a single 3.75 J/cm(2) exposure. RESULTS: A single 9 J/cm(2) dose of UVA reduced the cell growth to only 10% of controls after 24 hrs. By three days after a single 9 J/cm( 2) exposure, the number of live cells was only 70% of controls. Three intermittent exposures of 3 J/cm(2) each for three consecutive days reduced the cell number to 76% of controls. Similar results were obtained for HLE cells. Little if any recovery of cell numbers occurred after three intermittent exposures. A single dose of 3.7 J/cm(2) reduced RLE catalase activity to 20% of controls by one day. By three days after exposure, catalase activity returned to 90% of controls. After three intermittent exposures to 1.25 J/cm(2) each, over three days, RLE catalase activity was reduced to 75% of the controls. There appeared to be no recovery within two additional days. CONCLUSIONS: While single below lethal doses of UVA allow no recovery of RLE or HLE cell growth, partial recovery does occur after several daily intermittent exposures. Recovery of the catalase activity by RLE cells does occur after single sub lethal exposures, but intermittent exposures allow no recovery. The recovery of lens epithelial cell growth and catalase activity from UVA damage varies with the exposure regimen.

Animals↗
PubMed1999

DNA-based vaccine against La Crosse virus: protective immune response mediated by neutralizing antibodies and CD4+ T cells.

La Crosse virus (LACV)-mediated encephalitis is the most frequently reported arboviral disease in the United States, but to date no vaccine against this virus is available. We have established a new animal model, genetically targeted mice lacking a functional interferon type I receptor (IFNAR-1). These mice show an age-independent susceptibility to LACV and develop an acute encephalitis within 6 days of infection, thereby allowing the evaluation of vaccines against LACV. Taking advantage of this knockout mouse model, we have assessed the feasibility of DNA vaccination against this viral disease. Plasmid DNAs, encoding either the virus surface glycoproteins G1 and G2 or the internal nucleocapsid protein N, were used to immunize IFNAR-1-deficient mice. Mice vaccinated with DNA encoding the glycoproteins G1 and G2 produced neutralizing antibodies and exhibited a high degree of protection against challenge with high doses of LACV. Depletion of CD4+ T cells in mice vaccinated with DNA encoding G1/G2 reduced their capacity to control the infection. Virus titration and immunohistological analysis revealed that the protected mice showed no evidence of LACV particles in the brain. This indicates that the vaccine-induced immune response efficiently blocked viral spreading from the primary replication site to the brain. In contrast, immunization with DNA encoding protein N yielded only a partial protective effect that can be attributed to the cellular immune response. Taken together, this study shows that DNA vaccines can be designed to efficiently induce a protective immune response based on neutralizing antibodies and CD4+ T cells.

Animals↗
PubMed1999

Eukaryotic signalling domain homologues in archaea and bacteria. Ancient ancestry and horizontal gene transfer.

Phyletic distributions of eukaryotic signalling domains were studied using recently developed sensitive methods for protein sequence analysis, with an emphasis on the detection and accurate enumeration of homologues in bacteria and archaea. A major difference was found between the distributions of enzyme families that are typically found in all three divisions of cellular life and non-enzymatic domain families that are usually eukaryote-specific. Previously undetected bacterial homologues were identified for# plant pathogenesis-related proteins, Pad1, von Willebrand factor type A, src homology 3 and YWTD repeat-containing domains. Comparisons of the domain distributions in eukaryotes and prokaryotes enabled distinctions to be made between the domains originating prior to the last common ancestor of all known life forms and those apparently originating as consequences of horizontal gene transfer events. A number of transfers of signalling domains from eukaryotes to bacteria were confidently identified, in contrast to only a single case of apparent transfer from eukaryotes to archaea.

Amino Acid Sequence↗
PubMed1999

Long-lasting anti-metastatic efficiency of interleukin 12-encoding plasmid DNA.

Intramuscular injection of plasmid DNA encoding both subunits of the cytokine interleukin 12 (IL-12) exhibits strong antimetastatic activity against lung metastases induced by the malignant melanoma cell line B16-F10. The protective effect of IL-12 DNA is long-lasting, since administration of tumor cells 9 days after IL-12 DNA treatment prevented metastasis formation. No effects were observed with empty plasmid controls, DNA encoding the melanoma-associated antigen pmel17/gp100, the granulocyte-macrophage colony-stimulating factor GM-CSF, B7.1, or CpG-containing oligodeoxynucleotides. IL-12 DNA is required during early phases of metastasis formation and is ineffective when administered later. Its efficiency is dose dependent. The cytotoxic T cell response contributes to the antimetastatic effect as evidenced by genetically modified CD8- or perforin knockout mice. Depletion of natural killer (NK) cells by antibodies completely abrogated the effect. In contrast, the IL-12-induced antimetastatic effect was not mediated by interferon gamma (IFN-gamma) or tumor necrosis factor alpha (TNF-alpha) as shown with IFN-gamma receptor and TNF-alpha knockout mice, respectively. Toxic side effects by IL-12 were low. Our results suggest that plasmid DNA encoding IL-12 might have potential value as gene medicine against the initiation of metastasis formation.

Animals↗
PubMed1999

SMART: identification and annotation of domains from signalling and extracellular protein sequences.

SMART is a simple modular architecture research tool and database that provides domain identification and annotation on the WWW (http://coot.embl-heidelberg.de/SMART). The tool compares query sequences with its databases of domain sequences and multiple alignments whilst concurrently identifying compositionally biased regions such as signal peptide, transmembrane and coiled coil segments. Annotated and unannotated regions of the sequence can be used as queries in searches of sequence databases. The SMART alignment collection represents more than 250 signalling and extracellular domains. Each alignment is curated to assign appropriate domain boundaries and to ensure its quality. In addition, each domain is annotated extensively with respect to cellular localisation, species distribution, functional class, tertiary structure and functionally important residues.

Amino Acid Sequence↗
PubMed1999

Identification of factors responsible for postdialysis fatigue.

Ultrafiltration, diffusion, osmotic shifts, blood-membrane interactions, and psychological factors have all been implicated in the pathogenesis of postdialysis fatigue (PDF). To identify responsible factors, we performed a prospective, randomized, crossover analysis of fatigue scores (scale, 0 to 4) in 12 maintenance hemodialysis subjects with PDF. Fatigue scores were evaluated on nondialysis days (baseline) and after the following procedures on midweek treatment days: standard dialysis using either a 135- to 140-mEq/L sodium bath (routine hemodialysis) or a 150- to 155-mEq/L sodium bath (hypernatric hemodialysis); isolated ultrafiltration; isolated diffusion; and sham procedures with (isolated membrane) or without (recirculation) exposure to a dialysis membrane. Maximal fatigue scores are expressed as mean and 95% confidence intervals (CIs). The highest scores were recorded by patients who had just undergone routine hemodialysis (mean score, 2. 6; 95% CI, 1.7 to 3.4), isolated ultrafiltration (mean score, 2.1; 95% CI, 1.3 to 2.9), and isolated diffusion (mean score, 2.4; 95% CI, 1.5 to 3.2). There were no significant differences in fatigue scores between baseline periods and isolated membrane and recirculation procedures (mean score, 1.3; 95% CI, 0.4 to 2.2). Fatigue scores after hypernatric hemodialysis occupied an intermediate position (mean score, 1.7; 95% CI, 0.8 to 2.6). These results suggest that rapid hydraulic and molecular flux have a greater role in the pathogenesis of PDF than psychological stress and blood-membrane interactions. Use of a high-sodium bath may ameliorate PDF. We conclude that appropriate adjustments in both ultrafiltration and sodium profiling remain the most important means for controlling PDF in patients on short-duration hemodialysis.

Cross-Over Studies↗
PubMed1999

Fatigue in mothers of infants discharged to the home on apnea monitors.

A comparative study was done to determine differences in caregiver fatigue between two groups of mothers of preterm infants at baseline, in the hospital (Time 1), 1 week postdischarge (Time 2), and 1 month postdischarge (Time 3). Group 1 infants were discharged home on apnea monitors (AM) (n = 28), and Group 2 infants were not on apnea monitors (nonAM)(n = 46). Measured by the Multidimensional Assessment of Fatigue (MAF) scale, mean fatigue scores from Time 1 to Time 3 markedly increased for the monitor group and decreased for the nonmonitor group. The scores were significantly different between the two groups at Times 2 and 3 but not at baseline. Two-way analysis of variance (ANOVA) with repeated measures showed group by time interaction effects on fatigue. Monitoring and alleviation of fatigue in home caregivers of preterm infants on apnea monitors are necessary.

Adolescent↗
PubMed1999

Protein families in multicellular organisms.

The complete sequence of the nematode worm Caenorhabditis elegans contains the genetic machinery that is required to undertake the core biological processes of single cells. However, the genome also encodes proteins that are associated with multicellularity, as well as others that are lineage-specific expansions of phylogenetically widespread families and yet more that are absent in non-nematodes. Ongoing analysis is beginning to illuminate the similarities and differences among human proteins and proteins that are encoded by the genomes of the multicellular worm and the unicellular yeast, and will be essential in determining the reliability of transferring experimental data among phylogenetically distant species.

Animals↗
PubMed1999

Reduced melanoma tumor formation in mice immunized with DNA expressing the melanoma-specific antigen gp100/pmel17.

Plasmid DNA encoding gene products of viruses or other pathogens has recently been applied by intramuscular injection as a novel type of vaccine. It can induce cytotoxic T cell response in small animals and protect against challenge with influenza A viruses. Combinations with cytokines or DNA-encoding cytokines have been applied in order to increase the efficiency of protection. A DNA vaccine has been analyzed here against malignant melanoma encoding gp100/pmel17, a melanoma-associated antigen. A small animal model was used by injection of B16 melanoma cells to syngeneic C57Bl/6 mice. DNA vaccination before tumor cell challenge leads to about 50% reduction of tumor size. The cytokine gene coding for GM-CSF did not increase the efficiency but also led to tumor size reduction when applied alone.

Animals↗
PubMed1999

Development of a percutaneous fiberoptic hepatic venous localization catheter.

OBJECTIVE: To develop a liver-specific biosensor system/catheter assembly that can be used to localize and cannulate the hepatic venous system without the need for fluoroscopic imaging. This would permit the bedside placement of a hepatic venous catheter for monitoring purposes without radiographic guidance. DESIGN: Experimental, in vitro. STUDY SETTING: Experimental laboratory at a university center. SUBJECT: This was a simulation study to evaluate the ability of a cardiovascular monitoring catheter mounted with a liver-specific biosensor to anatomically identify a side arm tributary. The experimental system used for this study mimics the hepatic vein draining into the inferior vena cava and allows its localization without the need for assisted imaging. The biosensor design and catheter/sensor assembly function were studied in this in vitro model. INTERVENTIONS: A liver-specific biosensor was developed by housing a homogeneous affinity fluorescence assay system sensitive to galactose in a microdialysis hollow fiber receptacle. A polyvinyl chloride tube containing a side arm was constructed to mimic the confluence of a venous tributary (i.e., the hepatic vein) with a major vascular channel (i.e., the vena cava). In this simulation, the side arm was continuously perfused with a liver-sensitive analyte (galactose) and the main channel was perfused with galactose-free buffer. A cardiovascular catheter containing a fiberoptic waveguide mounted with a galactose-sensitive fluorescent probe was advanced along the main conduit to assess its ability to identify the location of the galactose side arm infusion site. MEASUREMENTS AND MAIN RESULTS: The response of the fiberoptic sensor to different galactose concentrations was assessed and found to be almost linear over the concentration range of 0 to 2 mM, which encompasses the expected utilization range of this system. The variability in identifying the galactose infusion point (simulated hepatic vein) in a 15-cm conduit was 1.7 to 2.8 mm, or 1.1% to 1.9%. CONCLUSIONS: The construction of a catheter/sensor system with the ability to provide accurate spatial/anatomical localization data for the hepatic venous system is feasible. This assembly will eliminate the need for ancillary imaging systems for catheter/sensor delivery to an individual organ system and potentially can be positioned at the bedside in a fashion similar to the pulmonary artery flotation catheter.

Bias↗
PubMed1999

Fluorescence studies of lens epithelial cells and their constituents.

Steady-state and time-resolved fluorescence measurements have been made of human and rabbit lens epithelial cells and their total soluble protein. Excitation at 350 nm results in broad fluorescence spectra peaking at 450 nm and stretching into the visible past 650 nm. The fluorescence excitation spectra peak around 350 nm. We assign the species responsible for this absorption and fluorescence as NADPH. Because the absorption of near-UV light (300-400 nm) is responsible for cell damage and death, we postulate that excited states of NADPH are implicated in the mechanisms of cell damage. Preirradiation with 355 nm light leads to a loss of NADPH fluorescence but with no change in decay kinetics. Possible mechanisms for cell damage are explored.

Animals↗
PubMed1998

SMART, a simple modular architecture research tool: identification of signaling domains.

Accurate multiple alignments of 86 domains that occur in signaling proteins have been constructed and used to provide a Web-based tool (SMART: simple modular architecture research tool) that allows rapid identification and annotation of signaling domain sequences. The majority of signaling proteins are multidomain in character with a considerable variety of domain combinations known. Comparison with established databases showed that 25% of our domain set could not be deduced from SwissProt and 41% could not be annotated by Pfam. SMART is able to determine the modular architectures of single sequences or genomes; application to the entire yeast genome revealed that at least 6.7% of its genes contain one or more signaling domains, approximately 350 greater than previously annotated. The process of constructing SMART predicted (i) novel domain homologues in unexpected locations such as band 4.1-homologous domains in focal adhesion kinases; (ii) previously unknown domain families, including a citron-homology domain; (iii) putative functions of domain families after identification of additional family members, for example, a ubiquitin-binding role for ubiquitin-associated domains (UBA); (iv) cellular roles for proteins, such predicted DEATH domains in netrin receptors further implicating these molecules in axonal guidance; (v) signaling domains in known disease genes such as SPRY domains in both marenostrin/pyrin and Midline 1; (vi) domains in unexpected phylogenetic contexts such as diacylglycerol kinase homologues in yeast and bacteria; and (vii) likely protein misclassifications exemplified by a predicted pleckstrin homology domain in a Candida albicans protein, previously described as an integrin.

Amino Acid Sequence↗
PubMed1998

The effect of anti-diuretic hormone on the endolymphatic sac of the inner ear.

The anti-diuretic hormone vasopressin (AVP) regulates water excretion from the kidney by increasing the water permeability of the collecting duct. AVP binds to V2-receptors and induces the translocation of aquaporin-2 water channels (AQP-2) into the apical plasma membrane of principal cells. By this mechanism AVP controls water reabsorption in the kidney. The effects of AVP on the endolymphatic sac (ES) of the inner ear, which is thought to mediate reabsorption of endolymph, were investigated. Both the V2-receptor and the AQP-2 water channel were found to be expressed in the ES epithelium. In the ES AVP binds to receptors most probably of the V2-subtype. Application of AVP to organotypically cultured ES inhibits membrane turnover in ribosomal-rich cells of the ES epithelia, which is thought to mediate translocation of AQP-2 into the surface membrane. This suggests that AVP has contrasting effects in the inner ear and kidney, which may be physiologically useful for maintaining endolymphatic pressure during severe hypovolemia. Animal experiments show that AVP causes endolymphatic hydrops after systemic application to guinea-pigs, which suggests a causal role for the increased AVP levels found in humans suffering from Ménière's disease.

Animals↗