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Biomedical subjects

J Smiley

Publications and source records attributed to J Smiley.

10 recordsLinked to original sources
PubMed2001

Continuous phencyclidine treatment induces schizophrenia-like hyperreactivity of striatal dopamine release.

Functional dopaminergic hyperactivity is a key feature of schizophrenia. Recent in vivo imaging studies have demonstrated greater striatal dopamine release in response to amphetamine challenge in schizophrenia subjects than in normal controls. N-methyl-D-aspartate (NMDA) receptors are known to play a prominent role in regulation of striatal dopamine release. In humans, NMDA antagonists induce a psychotic state that closely resembles schizophrenia. The present study investigates the degree to which chronic continuous administration of the NMDA antagonist phencyclidine (PCP) induces schizophrenia-like hyperreactivity of striatal dopamine release to amphetamine in rodents. Rats were treated with 10 or 15 mg/kg/d PCP for two weeks by osmotic minipump, and striatal dopamine release to amphetamine challenge (1 mg/kg) was monitored by microdialysis. PCP-treated rats showed significant enhancement in amphetamine-induced dopamine release, along with significantly enhanced locomotor activity. These findings support the concept that NMDA receptor dysfunction may contribute to dopaminergic dysfunction in schizophrenia.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1998

Pediatric blood volumes: a one-page reference guide.

At our institution, a multidisciplinary team met to work out a blood volume policy for our pediatric patients' laboratory testing. Because we are a cancer center, many of our patients are on protocols and/or are in the hospital for an extended period of time. These factors result in multiple blood draws. It is important to manage the volumes used so that we do not compromise the hematological status of our pediatric patients. The concerns of nurses and laboratory technologists were discussed and a three-tiered system was designed consisting of adult volumes, volumes for < 20-kg patients, and volumes for < 10-kg patients. Each tier consists of less blood than the one above it but the cost for such a procedure is increased. Time to conduct the draw, the cost of equipment to do the draw, and inflexibility to verify or add to the original order without resticking the patient increase at each tier. It is imperative to the overall quality of care for all patients that discretion is used when following these guidelines. When it is medically prudent to restrict the blood volumes taken from any patient, it should be done. However, when it is not medically necessary, the increased costs and potential decrease in the quality of laboratory service outweighs the desire to use smaller blood volumes.

Blood Volume↗
PubMed1994

Catalytic antibodies: perusing combinatorial libraries.

Combinatorial libraries are a promising alternative for isolating catalytic antibodies produced by the immune system in response to the transition-state analog of a given reaction. Large, diverse panels of antibodies with high affinity for the transition-state analog can be isolated using screening or selection approaches. Furthermore, we have estimated that nucleotide sequences that bear close similarity to the sequence for a known catalytic antibody occur in combination at frequencies sufficient for their detection in such libraries.

Amino Acid Sequence↗
PubMed1992

Regulation of the yeast DNA replication genes through the Mlu I cell cycle box is dependent on SWI6.

In Saccharomyces cerevisiae, at least 17 DNA replication genes are coordinately expressed at the G1/S boundary during the cell cycle. All of these genes have the DNA sequence element ACGCGT in their 5' upstream regulatory regions. This sequence has been shown to be essential for periodic expression of the POL1, CDC9, and TMP1 genes. The cyclin (CLN1 and CLN2) and HO genes are another subset of genes that are expressed with the same timing as the DNA replication genes. Their periodic expression requires the participation of two well-characterized transcriptional activators: the SWI4 and SWI6 gene products. In this study, we present evidence that SWI6 contributes to the regulation of DNA replication genes as well. Surprisingly, a preferential requirement for SWI6 over SWI4 is observed in our studies of ACGCGT-dependent reporter gene expression in vivo. This selectivity has not been observed for the other G1/S genes. Correlating with the in vivo results, protein-DNA complexes formed in vitro on multimeric ACGCGT elements are either abolished or reduced in swi6 delta deletion mutants.

Base Sequence↗
PubMed1984

Control of expression of the herpes simplex virus thymidine kinase gene in biochemically transformed cells.

A series of cell lines was constructed by transformation of murine LTK- cells with a family of deletion mutants of the herpes simplex virus (HSV) thymidine kinase (tk) gene. These mutants, differing in the extent of 5' sequence flanking the coding region for tk, varied in the frequency with which they were able to convert tk- cells to the tk+ phenotype. Converted cell lines were analysed for tk DNA sequences, tk mRNA sequences, the 5' terminus of tk-specific transcripts and for their ability to respond to a signal provided in trans by infecting tk- virus (transactivation). The results of these analyses reveal that transformation efficiency correlates inversely with the extent of 5' flanking information. Thus mutants retaining less than 109 bp of 5' sequences transform less efficiently than those that retain at least 109 bp. Cell lines established by transformation with mutants retaining the proximal 109 bp contain relatively few copies of tk DNA whereas those which arose as a result of transformation with mutant DNA containing less than 109 bp generally contained multiple copies of tk DNA. Analyses of tk-specific transcripts revealed that cell lines derived from plasmids that transformed efficiently synthesized an mRNA which was indistinguishable by its size or 5' end from infected cell mRNA. Cell lines established by plasmids that were inefficient at transformation accumulated truncated mRNAs that initiated at aberrant start sites. The presence of the 5' 109 bp block was required for transformants to increase the level of tk mRNA and enzyme when infected with a tk- deletion mutant of HSV. We also show that transactivation does not alter the initiation site of the tk mRNA synthesized by transformants.

Animals↗
PubMed1984

Therapeutic effects of an imposed foraging task in disturbed monkeys.

A group of twelve bonnet macaques (Macaca radiata) raised in partial social isolation from birth to adulthood expressed moderate-to-severe behavioral disturbance as a function of their early rearing environments. The range of these behavioral function of their early rearing environments. The range of these behavioral abnormalities in this species are described for the first time. In order to assess the role of the current environment on their behavior, the animals as a group were required to obtain all of their food from a foraging device presenting two levels of difficulty. The therapeutic effect of the imposed foraging task was dependent upon the individual's status in the dominance hierarchy. Low- and high-ranking animals responded positively and became more social (338% above baseline levels) and showed lower levels of specific abnormal behaviors (nearly 75% lower). Mid-ranking animals responded negatively and became less social (89% lower), while their levels of abnormal behavior dramatically increased (200% higher).

Animals↗
PubMed1983

Generation of dimethylnitrosamine in water purification systems. Detection in human blood samples during hemodialysis.

Dimethylnitrosamine (DMNA), a carcinogen, was detected at levels up to 32 micrograms/L in dialysate from five of 16 dialysis units surveyed. Blood drawn from patients at one of these units in which DMNA was raised in the dialysate showed a significant increase in the amount of DMNA in the patient's blood when predialysis levels were compared with 15-minute intradialysis levels. The presence of a mixed-bed deionizer without an antecedent carbon filter appeared to be necessary for DMNA production. These data suggest that DMNA is generated in certain water purification systems and may then diffuse into the patient's blood. Guidelines for deionizer-treated water should be revised to include an activated carbon filter.

Adolescent↗
PubMed1980

Weight gain in bonnet and pigtail macaques.

Developmental weight gain was traced in two species of macaque, Macaca radiata and Macaca nemestrina. Some similarities in growth patterns between the two species were observed. Spontaneous obesity in bonnet macaques was observed, and growth curves of these specimens were compared with those of normal animals.

Aging↗
PubMed1977

Characteristics of a human cell line transformed by DNA from human adenovirus type 5.

Human embryonic kidney cells have been transformed by exposing cells to sheared fragments of adenovirus type 5 DNA. The transformed cells (designated 293 cells) exhibited many of the characteristics of transformation including the elaboration of a virus-specific tumour antigen. Analysis of the polypeptides synthesized in the 293 cells by labelling with 35S-methionine and SDS PAGE showed a variable pattern of synthesis, different in a number of respects from that seen in otheruman cells. On labelling the surface of cells by lactoperoxidase catalysed radio-iodination, the absence of a labelled polypeptide analogous to the 250 K (LETS) glycoprotein was noted. Hybridization of labelled cellular RNA with restriction fragments of adenovirus type 5 DNA indicated transcription of a portion of the adenovirus genome at the conventional left hand end.

Adenoviruses, Human↗