Biomedical subjects

R Wiese

Publications and source records attributed to R Wiese.

9 recordsLinked to original sources

PubMed2001

DNA microarrays based on noncovalent oligonucleotide attachment and hybridization in two dimensions.

Short oligonucleotide probes have been linked to a solid support by simple electrostatic adsorption onto a positively charged surface film. Attachment was obtained by microfluidic application of unmodified oligonucleotides in distilled water onto amino-silanized glass. It has been demonstrated that an extremely stable monolayer of oligonucleotide is obtained by this method, at a density of about 10(11) molecules/mm(2), which approaches the limit expected for a two-dimensional closest-packed array. Application of oligonucleotide by adsorption is followed by capping with acetic anhydride in the vapor phase, and then capping with succinic anhydride in solution to form a surface with weak negative charge. The capping method has been successfully employed for microarray fabrication and for the analysis of single nucleotide polymorphisms in the k-ras gene. The data reveal that, subsequent to capping, the adsorptive association of oligonucleotide to the surface yields a probe layer which is capable of single nucleotide base mismatch discrimination and high apparent binding affinity.

Acetic Anhydrides↗

PubMed2001

Nearly instantaneous, cation-independent, high selectivity nucleic acid hybridization to DNA microarrays.

Hybridization rate enhancement has been demonstrated for high molecular weight DNA target binding to a microarray. Microarrays were fabricated using biotin-modified oligonucleotides complexed with streptavidin (SA), which serves as an attachment to the underlying surface. It is shown that at low salt and pH 5, where SA develops a positive charge, duplex formation becomes at least 80-fold faster than seen under standard conditions, where SA is neutral or anionic. Duplex formation becomes independent of solution state cation concentration in the low pH state, under conditions where specificity remains high. The utility of such applied surface science is discussed.

Biotin↗

PubMed2001

Simultaneous multianalyte ELISA performed on a microarray platform.

BACKGROUND: A logical progression of the widely used microtiter plate ELISA is toward a protein array format that allows simultaneous detection of multiple analytes at multiple array addresses within a single well. Here we describe the construction and use of such a multiplex ELISA to measure prostate-specific antigen (PSA), alpha1-antichymotrypsin-bound PSA (PSA-ACT), and interleukin-6 (IL-6). METHODS: We silanized glass plates and printed the appropriate capture antibodies to allow for the construction of "sandwich" ELISA quantification assays. We examined specificity of the assay for appropriate antigen, assembled calibration curves, and obtained PSA concentrations for 14 human serum samples. We compared the serum PSA concentrations derived through the use of our array with values obtained independently using a standard ELISA method. RESULTS: R2 values generated by our microarray for the PSA and PSA-ACT calibration curves were 0.989 and 0.979, respectively. Analyte concentrations used for the construction of these curves were 0.31-20 microg of protein/L of diluent. IL-6 calibration curve concentrations were 4.9-300 ng of IL-6/L of diluent. The R2 value for the IL-6 calibration curve was 0.983. The 14 human serum samples screened by this micro-ELISA technique for PSA concentrations generated a regression equation (linear) with a slope of 0.83 +/- 0.10 and intercept of 0.74 +/- 0.70 (R2 = 0.88). CONCLUSIONS: Multiplexed ELISA arrays are a feasible option for analyte quantification in complex biologic samples.

Autoanalysis↗

PubMed2001

High-throughput genomic and proteomic analysis using microarray technology.

BACKGROUND: High-density microarrays are ideally suited for analyzing thousands of genes against a small number of samples. The next step in the discovery process is to take the resulting genes of interest and rapidly screen them against thousands of patient samples, tissues, or cell lines to further investigate their involvement in disease risk or the response to medication. METHODS: We used a microarray technology platform for both single-nucleotide polymorphisms (SNPs) and protein expression. Each microarray contains up to 250 elements that can be customized for each application. Slides contained either a 16- or 96-microarray format (4000-24,000 elements per slide), allowing the corresponding number of samples to be rapidly processed in parallel. RESULTS: Results for SNP genotyping and protein profiling agreed with results of restriction fragment length polymorphism (RFLP) analysis or ELISA, respectively. Genotyping analyses, using the microarray technology, on large sample sets over multiple polymorphisms in the NAT2 gene were in full agreement with traditional methodologies, such as sequencing and RFLP analysis. The multiplexed protein microarray had correlation coefficients of 0.82-0.99 (depending on analyte) compared with ELISAs. CONCLUSIONS: The integrated microarray technology platform is adaptable and versatile, while offering the high-throughput capabilities needed for drug development and discovery applications.

Arylamine N-Acetyltransferase↗

PubMed1995

German inflection: the exception that proves the rule.

Language is often explained as the product of generative rules and a memorized lexicon. For example, most English verbs take a regular past tense suffix (ask-asked), which is applied to new verbs (faxed, wugged), suggesting the mental rule "add -ed to a Verb." Irregular verbs (break-broke, go-went) would be listed in memory. Alternatively, a pattern associator memory (such as a connectionist network) might record all past tense forms and generalize to new ones by similarity; irregular and regular patterns would differ only because of their different numbers of verbs. We present evidence that mental rules are indispensible. A rule concatenates a suffix to a symbol for verbs, so it does not require access to memorized verbs or their sound patterns, but applies as the "default," whenever memory access fails. We find 21 such circumstances for regular past tense formation, including novel, unusual-sounding, and rootless and headless derived words; in every case, people inflect them regularly (explaining quirks like flied out, sabre-tooths, walkmans). Contrary to the connectionist account, these effects are not due to regular words constituting a large majority of vocabulary. The German participle -t applies to a much smaller percentage of verbs than its English counterpart, and the German plural -s applies to a small minority of nouns. But the affixes behave in the language like their English counterparts, as defaults. We corroborate this effect in two experiments eliciting ratings of participle and plural forms of novel German words. Thus default suffixation is not due to numerous regular words reinforcing a pattern in associative memory. Because default cases do not occupy a cohesive similarity space, but do correspond to the range of a symbol, they are evidence for a memory-independent, symbol-concatenating mental operation.

Adult↗

PubMed1994

[Shock and coagulation disorders in systemic mastocytosis].

A 41-year-old man was admitted in circulatory shock of unknown aetiology (systolic pressure 50 mm Hg) and marked reddening of the upper part of the body as well as maculopapular rash over the whole body. After 1500 ml of colloidal solution had been infused the blood pressure rose to a level at which the patient's condition was no longer at risk. He reported having had a similar attack of flushing and circulatory collapse during the last few years, each time after drinking 3-41 of beer. Laboratory tests showed thromboplastin time 56%, partial thromboplastin time 130 s and thrombin time > 180 s. Three hours after admission the coagulation times had further deteriorated, but had become normal within 20 hours. After rest and after a provocation (hot bath) the serum concentrations were: heparin 0.21 U/ml and 0.85 U/ml; histamine 1.9 micrograms/ml and 2.3 micrograms/ml; serotonin 23 micrograms/ml and 38 micrograms/ml. Histological examination of an iliac crest bone marrow biopsy revealed dense collections of mast cells, as seen in systemic mastocytosis. A skin biopsy was diagnostic of urticaria pigmentosa.

Adult↗

PubMed1991

The Sp1 transcription factor gene (SP1) and the 1,25-dihydroxyvitamin D3 receptor gene (VDR) are colocalized on human chromosome arm 12q and rat chromosome 7.

By means of somatic cell hybrids segregating either human or rat chromosomes, the genes encoding the transcription factor Sp1 (SP1) and the 1,25-dihydroxyvitamin D3 receptor (VDR) were both assigned to human chromosome arm 12q and to rat chromosome 7. This result implies that the locus for the clinical disorder vitamin D dependency rickets type II maps on 12q. The phenylalanine hydroxylase (PAH) and the retinoic acid receptor-gamma (RARG) genes also map on human chromosome arm 12q and rat chromosome 7, indicating that a synteny group is conserved on these chromosomes.

Animals↗

PubMed1985

Anemonia sulcata toxin (ATX II) enhances spontaneous electrical activity and tension in chronically denervated rat diaphragm.

In isolated strips of rat diaphragm denervated 9-21 days prior to experimentation, spontaneous action potentials were recorded extracellularly and twitch and resting tension were measured. The sea anemone toxin ATX II enhances the occurrence of spontaneous action potentials, increases resting tension and depresses twitch tension. These effects are essentially irreversible. In low sodium solution substituted with sucrose the effects of ATX II are attenuated, however, they fully develop upon return to normal sodium solution with a marked transient increase in the incidence of spontaneous action potentials and in resting tension. ATX II remains uneffective after pretreatment with tetrodotoxin. Reelevation of the extracellular sodium concentration after exposure to low sodium solution per se causes a marked increase in occurrence of fibrillation potentials, however the transient increase in resting tension was much smaller than in the presence of ATX II. Substitution of chloride with the impermeable anion methylsulphate enhances spontaneous activity and resting tension without an effect on twitch tension. Addition of ATX II elevates resting tension although the concomitant further increase in incidence of spontaneous action potentials is small. It is concluded that the increase in resting tension reflects a summation of the fibrillatory activity, but fibrillations become more effective when the preparations are exposed to ATX II. This finding points at the possible rôle of sodium ions in excitation contraction coupling of denervated skeletal muscle.

Action Potentials↗

PubMed1981

Teaching nutritional assessment to nursing students.

A data collection tool was developed to teach nursing students basic principles of nutritional assessment. The tool was used to help nurses coordinate and interpret data they routinely collected so they would be more aware of real and potential nutritional problems. Emphasis was on those aspects of nutritional care relevant to the nurse's advocates in communicating these concerns to the dietitian. Observation and early referral of potential diet-related problems enables the dietitian to more effectively provide for nutritional care.

Curriculum↗