Biomedical subjects

J Killian

Publications and source records attributed to J Killian.

17 recordsLinked to original sources

PubMed2003

Chemical RNA labeling without 3' end bias using fluorescent cis-platin compounds.

Recently, fluorescent, monofunctional cis-platin derivatives have been developed to chemically label nucleic acids for use in fluorescent hybridization assays. Here we show by hybridizations to microarrays containing oligonucleotide probes for the 3' ends, middle parts, and 5' ends of mRNAs, that this labeling methodology bypasses the problem of the 3' end bias that is characteristic of the conventional enzymatic oligo(dT)-primed, reverse transcription labeling of mRNAs.

DNA↗

PubMed2001

Universal Linkage System: versatile nucleic acid labeling technique.

Over the last two decades nonradioactive nucleic acid labeling and detection systems have overcome the safety, disposal, stability and cost problems that are associated with radioactive techniques. Besides traditional, enzyme-mediated, nonradioactive labeling methods (e.g., random priming, nick translation or labeling by PCR), several chemical labeling systems have been developed (e.g., ULS, psoralen, alkylating agents). These methods provide fluorescent (or hapten) labeled probes for fluorescence in situ hybridization (FISH), comparative genomic hybridization (CGH) and microarray-based techniques. In this review the DNA-based molecular diagnostic applications and perspectives of the Universal Linkage System (ULS) technology will be described.

Chlamydia trachomatis↗

PubMed2000

Reactivity and regulatory properties of human anti-idiotypic antibodies induced by T cell vaccination.

Immunization with irradiated autoreactive T cells (T cell vaccination) induces anti-idiotypic T cell responses that preferentially recognize complementarity-determining region 3 sequences, contributing to clonal depletion of autoreactive T cells. However, it remains unknown whether T cell vaccination elicits anti-idiotypic humoral responses and whether the anti-idiotypic Abs play a similar role in the regulatory mechanism induced by T cell vaccination. In this study we examined the occurrence, the reactivity pattern, and the regulatory role of anti-idiotypic Abs elicited by T cell vaccination in patients with multiple sclerosis. We demonstrated for the first time that B cells producing anti-idiotypic Abs could be isolated from vaccinated patients. These EBV-transformed B cell lines were selected for specific reactivity to a 20-mer TCR peptide incorporating a common complementarity-determining region 3 sequence of the immunizing T cell clones. The resulting anti-idiotypic Abs were found to react with the original immunizing T cell clones and exhibit an inhibitory effect on their proliferation. The findings suggest that anti-idiotypic Ab responses can be induced by T cell vaccination in humans and that their regulatory properties are likely to contribute to the suppression of myelin basic protein-reactive T cells in vaccinated patients. The study has important implications in our understanding of the regulatory role of the anti-idiotypic humoral responses induced by T cell vaccination.

Adoptive Transfer↗

PubMed2000

Preferential recognition of TCR hypervariable regions by human anti-idiotypic T cells induced by T cell vaccination.

T cell responses to myelin basic protein (MBP) are potentially involved in the pathogenesis of multiple sclerosis (MS). Immunization with irradiated MBP-reactive T cells (T cell vaccination) induces anti-idiotypic T cell responses that suppress circulating MBP-reactive T cells. This T cell-T cell interaction is thought to involve the recognition of TCR expressed on target T cells. The study was undertaken to define the idiotypic determinants responsible for triggering CD8+ cytotoxic anti-idiotypic T cell responses by T cell vaccination in patients with MS. A panel of 9-mer synthetic TCR peptides corresponding to complementarity-determining region 2 (CDR2) and CDR3 of the immunizing MBP-reactive T cell clones were used to isolate anti-idiotypic T cell lines from immunized MS patients. The resulting TCR-specific T cell lines expressed exclusively the CD8 phenotype and recognized preferentially the CDR3 peptides. CDR3-specific T cell lines were found to lyze specifically autologous immunizing MBP-reactive T cell clones. The findings suggest that CDR3-specific T cells represented anti-idiotypic T cell population induced by T cell vaccination. In contrast, the CDR2 peptides were less immunogenic and contained cryptic determinants as the CDR2-specific T cell lines did not recognize autologous immunizing T cell clones from which the peptide sequence was derived. The study has important implications in our understanding of in vivo idiotypic regulation of autoimmune T cells and the regulatory mechanism underlying T cell vaccination.

Amino Acid Sequence↗

PubMed1999

Incremental costs of enrolling cancer patients in clinical trials: a population-based study.

BACKGROUND: Payment for care provided as part of clinical research has become less predictable as a result of managed care. Because little is known at present about how entry into cancer trials affects the cost of care for cancer patients, we conducted a matched case-control comparison of the incremental medical costs attributable to participation in cancer treatment trials. METHODS: Case patients were residents of Olmsted County, MN, who entered phase II or phase III cancer treatment trials at the Mayo Clinic from 1988 through 1994. Control patients were patients who did not enter trials but who were eligible on the basis of tumor registry matching and medical record review. Sixty-one matched pairs were followed for up to 5 years after the date of trial entry for case patients or from an equivalent date for control patients. Hospital, physician, and ancillary service costs were estimated from a population-based cost database developed at the Mayo Clinic. RESULTS: Trial enrollees incurred modestly (no more than 10%) higher costs over various follow-up periods. The mean cumulative 5-year cost in 1995 inflation-adjusted U.S. dollars among trial enrollees after adjustment for censoring was $46424 compared with $44 133 for control patients. After 1 year, trial enrollee costs were $24645 compared with $23 964 for control patients. CONCLUSIONS: This study suggests that cancer chemotherapy trials may not imply budget-breaking costs. Cancer itself is a high-cost illness. Clinical protocols may add relatively little to that cost.

Cancer Care Facilities↗

PubMed1999

DNA rearrangements on both homologues of chromosome 17 in a mildly delayed individual with a family history of autosomal dominant carpal tunnel syndrome.

Disorders known to be caused by molecular and cytogenetic abnormalities of the proximal short arm of chromosome 17 include Charcot-Marie-Tooth disease type 1A (CMT1A), hereditary neuropathy with liability to pressure palsies (HNPP), Smith-Magenis syndrome (SMS), and mental retardation and congenital anomalies associated with partial duplication of 17p. We identified a patient with multifocal mononeuropathies and mild distal neuropathy, growth hormone deficiency, and mild mental retardation who was found to have a duplication of the SMS region of 17p11.2 and a deletion of the peripheral myelin protein 22 (PMP22) gene within 17p12 on the homologous chromosome. Further molecular analyses reveal that the dup(17)(p11.2p11.2) is a de novo event but that the PMP22 deletion is familial. The family members with deletions of PMP22 have abnormalities indicative of carpal tunnel syndrome, documented by electrophysiological studies prior to molecular analysis. The chromosomal duplication was shown by interphase FISH analysis to be a tandem duplication. These data indicate that familial entrapment neuropathies, such as carpal tunnel syndrome and focal ulnar neuropathy syndrome, can occur because of deletions of the PMP22 gene. The co-occurrence of the 17p11.2 duplication and the PMP22 deletion in this patient likely reflects the relatively high frequency at which these abnormalities arise and the underlying molecular characteristics of the genome in this region.

Adolescent↗

PubMed1998

Minimal RNA constructs that specifically bind aminoglycoside antibiotics with high affinities.

RNA molecules are the functional targets for aminoglycosides. In order to approach an understanding of the rules which underlie aminoglycoside-RNA recognition, high-affinity RNA aptamers have been prepared which discriminate among various aminoglycosides [Wang et al. (1996) Biochemistry 35, 12338-12346]. One of these aptamers, J6, which is 109 nts in length, binds the aminoglycoside tobramycin stoichiometrically with a dissociation constant of 0.77 +/- 0.03 nM. Aminoglycosides, similar in structure to tobramycin, bind with affinities diminished by 10(3)-10(4) compared to tobramycin. Experiments are reported here which are designed to reveal the nature of the tobramycin binding domain of J6. A small (40 nts) stem-loop derivative of J6, containing a 3 nt and a 1 nt bulge, stoichiometrically binds tobramycin with a dissociation constant of approximately 5 nM. This construct can strongly discriminate between similar aminoglycosides with respect to binding. Elimination of either the three or the single nucleotide bulge eliminates specific aminoglycoside binding. The structure of the loop region is also critical. These studies demonstrate that simplified RNA molecules can be generated which bind aminoglycosides specifically and with high affinities.

Aminoglycosides↗

PubMed1997

Deciphering the language of the genome.

The non-coding DNA in eukaryotic genomes encodes a language which programs organismal growth and development. We show that a linguistic and cryptographic approach can be used to deduce the syntax of this programming language for gene regulation and to compile a dictionary of enhancers which form its words.

Animals↗

PubMed1996

RNA molecules that specifically and stoichiometrically bind aminoglycoside antibiotics with high affinities.

RNA aptamers had previously been selected which were able to bind to the aminoglycoside antibiotic tobramycin with high affinity (Wang & Rando, 1995). Consensus sequences are found in a variety of constructs, and these sequences were mapped to stem-loop regions by Mfold secondary structure prediction. A tobramycin-based affinity cleavage reagent specifically cleaves the aptamers in their consensus regions. A fluorescence depolarization method is developed to accurately measure the affinity and stoichiometry of aminoglycoside binding to RNA constructs. An RNA aptamer (J6RNA) selected to bind to the aminoglycoside antibiotic tobramycin is shown to do so with an affinity of 0.77 nM and a stoichiometry of 1:1. (Fluorescently labeled) 5-carboxytetramethylrhodamine tobramycin (CRT) is used as a ligand in the fluorescence depolarization studies. J6RNA binding is quite specific for tobramycin, and weakly binds structurally related aminoglycosides with affinities 10(3)-10(4)-fold lower than that for tobramycin. Specific aminoglycoside binding aptamers of this type should be useful for revealing the rules of RNA-aminoglycoside recognition.

Anti-Bacterial Agents↗

PubMed1996

Multi-disciplinary clinical study of Smith-Magenis syndrome (deletion 17p11.2)

Smith-Magenis syndrome (SMS) is a multiple congenital anomaly, mental retardation (MCA/MR) syndrome associated with deletion of chromosome 17 band p11.2. As part of a multi-disciplinary clinical, cytogenetic, and molecular approach to SMS, detailed clinical studies including radiographic, neurologic, developmental, ophthalmologic, otolaryngologic, and audiologic evaluations were performed on 27 SMS patients. Significant findings include otolaryngologic abnormalities in 94%, eye abnormalities in 85%, sleep abnormalities (especially reduced REM sleep) in 75%, hearing impairment in 68% (approximately 65% conductive and 35% sensorineural), scoliosis in 65%, brain abnormalities (predominantly ventriculomegaly) in 52%, cardiac abnormalities in at least 37%, renal anomalies (especially duplication of the collecting system) in 35%, low thyroxine levels in 29%, low immunoglobulin levels in 23%, and forearm abnormalities in 16%. The measured IQ ranged between 20-78, most patients falling in the moderate range of mental retardation at 40-54, although several patients scored in the mild or borderline range. The frequency of these many abnormalities in SMS suggests that patients should be evaluated thoroughly for associated complications both at the time of diagnosis and at least annually thereafter.

Abnormalities, Multiple↗

PubMed1991

North Carolina's dominant progressive foveal dystrophy: how progressive is it?

We studied 34 family members at risk of having dominant progressive foveal dystrophy of Lefler, Wadsworth, and Sidbury (also called North Carolina macular dystrophy) and found 17 to be affected. Fifteen of these affected subjects were observed over at least a 10-year period for evidence of progressive macular degeneration. Only one subject showed objective evidence of progressive deterioration in only one eye. Our findings further substantiate that this dystrophy generally has a stable course, contrary to its original description.

Adolescent↗

PubMed1990

Development and characterization of a lyophilized dosage form of IL-1 beta.

The development and characterization of a lyophilized dosage form for recombinant Interleukin-1 beta is described. Included in the evaluation of the drug product are accelerated and long-term stability studies utilizing a number of biophysical techniques (reverse-phase HPLC, SDS-PAGE, isoelectric focusing and ELISA). Data collected with these methods were examined for correlations with biological activity assessments provided by an in-vitro cell culture system (mouse thymocyte proliferation). Results of these studies demonstrate that a lyophilized dosage form of Interleukin-1 beta can be prepared which retains its potency for at least 1 year when stored at ambient temperature. The analytical methodology used to assess the physicochemical integrity of the protein provided a sensitive and reproducible means of predicting changes in biological activity.

Animals↗

PubMed1986