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J Schultz

Publications and source records attributed to J Schultz.

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

Accumulation of dietary cholesterol in sitosterolemia caused by mutations in adjacent ABC transporters.

In healthy individuals, acute changes in cholesterol intake produce modest changes in plasma cholesterol levels. A striking exception occurs in sitosterolemia, an autosomal recessive disorder characterized by increased intestinal absorption and decreased biliary excretion of dietary sterols, hypercholesterolemia, and premature coronary atherosclerosis. We identified seven different mutations in two adjacent, oppositely oriented genes that encode new members of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family (six mutations in ABCG8 and one in ABCG5) in nine patients with sitosterolemia. The two genes are expressed at highest levels in liver and intestine and, in mice, cholesterol feeding up-regulates expressions of both genes. These data suggest that ABCG5 and ABCG8 normally cooperate to limit intestinal absorption and to promote biliary excretion of sterols, and that mutated forms of these transporters predispose to sterol accumulation and atherosclerosis.

ATP Binding Cassette Transporter, Subfamily G, Mem↗
PubMed2000

A tetravalent single-chain antibody-streptavidin fusion protein for pretargeted lymphoma therapy.

Single-chain Fv antibody fragments from the CD20-specific murine monoclonal antibody B9E9 were genetically engineered as streptavidin fusions [single-chain Fv-streptavidin (scFvSA) fusion protein] for use in pretargeted radioimmunotherapy. The scFvSA constructs were expressed as soluble, tetrameric species in the periplasm of Escherichia coli. Expression levels were affected by the order of the variable regions and the length and composition of the single-chain Fv linker. The best expressor was obtained with the variable regions in the heavy chain-light chain configuration separated by a 25-mer Gly4Ser linker. This construct produced 250-300 mg of soluble, tetrameric fusion protein per liter of fermentor culture. The fusion protein (Mr 173,600) was purified from crude lysates by iminobiotin affinity chromatography with an overall yield of about 50% and was analyzed for functionality both in vitro and in vivo. Immunoreactivity of the scFvSA fusion protein and its nanomolar affinity to CD20-positive Ramos cells were comparable with the B9E9 monoclonal antibody. The fusion protein had a biotin dissociation rate identical to recombinant streptavidin and bound an average of 3.6 biotins/molecule of a possible 4 biotins/molecule. Labeled fusion protein cleared from the blood of BALB/c mice with a P half-life of about 16 h. In nude mice bearing Ramos xenografts, the fusion protein demonstrated sufficient tumor localization of functional streptavidin to enable efficient, tumor-specific targeting of a subsequently administered radionuclide-chelate/biotin molecule. These results suggest that large quantities of functional scFvSA can be produced for clinical testing as a therapy for non-Hodgkin's lymphoma.

Amino Acid Sequence↗
PubMed2000

Anopheles gambiae pilot gene discovery project: identification of mosquito innate immunity genes from expressed sequence tags generated from immune-competent cell lines.

Together with AIDS and tuberculosis, malaria is at the top of the list of devastating infectious diseases. However, molecular genetic studies of its major vector, Anopheles gambiae, are still quite limited. We have conducted a pilot gene discovery project to accelerate progress in the molecular analysis of vector biology, with emphasis on the mosquito's antimalarial immune defense. A total of 5,925 expressed sequence tags were determined from normalized cDNA libraries derived from immune-responsive hemocyte-like cell lines. The 3,242 expressed sequence tag-containing cDNA clones were grouped into 2,380 clone clusters, potentially representing unique genes. Of these, 1,118 showed similarities to known genes from other organisms, but only 27 were identical to previously known mosquito genes. We identified 38 candidate genes, based on sequence similarity, that may be implicated in immune reactions including antimalarial defense; 19 of these were shown experimentally to be inducible by bacterial challenge, lending support to their proposed involvement in mosquito immunity.

Animals↗
PubMed2000

SMART: a web-based tool for the study of genetically mobile domains.

SMART (a Simple Modular Architecture Research Tool) allows the identification and annotation of genetically mobile domains and the analysis of domain architectures (http://SMART.embl-heidelberg.de ). More than 400 domain families found in signalling, extra-cellular and chromatin-associated proteins are detectable. These domains are extensively annotated with respect to phyletic distributions, functional class, tertiary structures and functionally important residues. Each domain found in a non-redundant protein database as well as search parameters and taxonomic information are stored in a relational database system. User interfaces to this database allow searches for proteins containing specific combinations of domains in defined taxa.

Database Management Systems↗
PubMed2000

Male prevalence for reading disability is found in a large sample of black and white children free from ascertainment bias.

Male vulnerability to neurodevelopmental disorders remains controversial. For one disorder, reading disability, this sex bias has been interpreted as an artifact of referral bias. We investigated sex differences for the incidence of reading disability within a large prospective sample of White (N = 16,910) and Black (N = 15,313) children derived from the National Collaborative Perinatal Project (NCPP). Children were classified as having either moderate or severe reading disability when they had reading scores lower than 1.5 or 2.0 standard errors of prediction, respectively, given their age and intelligence. Reading disability was about twice as common in boys than girls (p < .001), irrespective of race, severity of disability, or exclusion of children with attentional disturbances or high activity levels. We conclude that there is a clear sex bias toward males for the incidence of reading disabilities.

Black or African American↗
PubMed2000

Proliferation of mitochondria in chronically stimulated rabbit skeletal muscle--transcription of mitochondrial genes and copy number of mitochondrial DNA.

Mitochondrial proliferation was studied in chronically stimulated rabbit skeletal muscle over a period of 50 days. After this time, subunits of COX had increased about fourfold. Corresponding mRNAs, encoded on mitochondrial DNA as well as on nuclear genes, were unchanged when related to total tissue RNA, however, they were elevated two- to fivefold when the massive increase of ribosomes per unit mass of muscle was taken into account. The same was true for the mRNA encoding mitochondrial transcription factor A. Surprisingly, tissue levels of mtTFA protein were reduced about twofold, together with mitochondrial DNA. In conclusion, mitochondria are able to maintain high rates of mitochondrial transcription even in the presence of reduced mtTFA protein and mtDNA levels. Therefore, stimulated mtTFA gene expression accompanies stimulated mitochondrial transcription, as in other models, but it is not sufficient for an increase of mtDNA copy number and other, yet unknown, factors have to be postulated.

Animals↗
PubMed2000

Refinement of the protein backbone angle psi in NMR structure calculations.

Cross-correlated relaxation rates involving the Calpha-Halpha dipolar interaction and the carbonyl (C') chemical shift anisotropy (CSA) have been measured using two complementary 3D experiments. We show that the protein backbone angle psi can be directly refined against such cross-correlated relaxation rates (gammaHalphaCalpha,C') and the three-bond H/D isotope effect on the Calpha chemical shifts (3 deltaCalpha(ND)). By simultaneously using both experimental parameters as restraints during NMR structure calculations, a unique value for the backbone angle psi is defined. We have applied the new refinement method to the alpha-Spectrin SH3 domain (a beta-sheet protein) and to the Sgs1p HRDC domain (an alpha-helical protein) and show that the quality of the NMR structures is substantially improved, judging from the atomic coordinate precision and the Ramachandran map. In addition, the psi-refined NMR structures of the SH3 domain deviate less from the 1.8 A crystal structure, suggesting an improved accuracy. The proposed refinement method can be used to significantly improve the quality of NMR structures and will be applicable to larger proteins.

Carbon↗
PubMed2000

More than 1,000 putative new human signalling proteins revealed by EST data mining.

Cloning procedures aided by homology searches of EST databases have accelerated the pace of discovery of new genes, but EST database searching remains an involved and onerous task. More than 1.6 million human EST sequences have been deposited in public databases, making it difficult to identify ESTs that represent new genes. Compounding the problems of scale are difficulties in detection associated with a high sequencing error rate and low sequence similarity between distant homologues. We have developed a new method, coupling BLAST-based searches with a domain identification protocol, that filters candidate homologues. Application of this method in a large-scale analysis of 100 signalling domain families has led to the identification of ESTs representing more than 1,000 novel human signalling genes. The 4,206 publicly available ESTs representing these genes are a valuable resource for rapid cloning of novel human signalling proteins. For example, we were able to identify ESTs of at least 106 new small GTPases, of which 6 are likely to belong to new subfamilies. In some cases, further analyses of genomic DNA led to the discovery of previously unidentified full-length protein sequences. This is exemplified by the in silico cloning (prediction of a gene product sequence using only genomic and EST sequence data) of a new type of GTPase with two catalytic domains.

Amino Acid Sequence↗
PubMed2000

Induction of long-lasting cytokine effect by injection of IL-12 encoding plasmid DNA.

We have recently demonstrated that DNA coding for both subunits of the murine IL-12 heterodimer exhibits a strong antimetastatic effect against B16-melanoma in C57BL/6 mice and after intratumoral injection tumor regression. Here we show that the antimetastatic effect can be detected when the DNA is injected intramuscularly 30 days before tumor cell challenge. A long-term IL-12 expression was measured for up to 50 days in the serum with a peak at day 20 amounting to about 10 ng/mL in C57BL/6 mice. CpG oligodeoxynucleotides also induce IL-12 expression, however, only for a few hours. IL-12 DNA administration induces long-lasting systemic IFN -gamma production, whereas IL-4 and TNF-alpha levels remained undetectable. NK cell-depleted mice showed a strong but reduced expression of murine IL-12. Expression of DNA encoding human instead of murine IL-12 resulted in a significantly lower and transient expression, indicating that not plasmid-derived IL-12 production alone but the immune system of the host contributes to the long- lasting antimetastatic effect. It may be attributable to an autocrine feedback mechanism maintaining murine IL- 12 expression, whereby several cell populations including NK cells are involved.

Animals↗
PubMed2000

Defects in protein glycosylation cause SHO1-dependent activation of a STE12 signaling pathway in yeast.

In haploid Saccharomyces cerevisiae, mating occurs by activation of the pheromone response pathway. A genetic selection for mutants that activate this pathway uncovered a class of mutants defective in cell wall integrity. Partial loss-of-function alleles of PGI1, PMI40, PSA1, DPM1, ALG1, MNN10, SPT14, and OCH1, genes required for mannose utilization and protein glycosylation, activated a pheromone-response-pathway-dependent reporter (FUS1) in cells lacking a basal signal (ste4). Pathway activation was suppressed by the addition of mannose to hexose isomerase mutants pgi1-101 and pmi40-101, which bypassed the requirement for mannose biosynthesis in these mutants. Pathway activation was also suppressed in dpm1-101 mutants by plasmids that contained RER2 or PSA1, which produce the substrates for Dpm1. Activation of FUS1 transcription in the mannose utilization/protein glycosylation mutants required some but not all proteins from three different signaling pathways: the pheromone response, invasive growth, and HOG pathways. We specifically suggest that a Sho1 --> Ste20/Ste50 --> Ste11 --> Ste7 --> Kss1 --> Ste12 pathway is responsible for activation of FUS1 transcription in these mutants. Because loss of pheromone response pathway components leads to a synthetic growth defect in mannose utilization/protein glycosylation mutants, we suggest that the Sho1 --> Ste12 pathway contributes to maintenance of cell wall integrity in vegetative cells.

Cell Wall↗
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↗
PubMed2000

Immune modulation in cancer using DNA inoculation--antitumour effect of interleukin-12.

DNA vaccines hold great promise for the prevention and therapy of infectious diseases and cancer. Furthermore, DNA has a high potential value not only for vaccination but also for therapy. Gene products which exhibit high potential biological potency, even at low levels of expression, are the most promising candidates. We have recently demonstrated that intramuscular injection of plasmid DNA coding for IL-12 abolishes the establishment of pulmonary metastases of 816F10 melanoma cells in a syngeneic mouse model. Based on these findings, we have evaluated the antitumour effect of IL-12 DNA therapy in a tumour model. Intramuscular injection of a murine IL-12-encoding DNA plasmid resulted in a pronounced reduction of tumour growth using preestablished syngeneic tumours in C57/BL6 mice. This antitumour effect correlated with a long-lasting expression of cytokines, which manifested itself as high levels of IL-12 in the serum 12 days after DNA treatment. The absence of significant toxic side effects could represent a significant advantage of IL-12 DNA therapy.

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↗