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Biomedical subjects

L K Miller

Publications and source records attributed to L K Miller.

At least 109 records · Page 6Linked to original sources
PubMed1992

Correlation of eye color on self-paced and reactive motor performance.

Researchers continue to examine the distinctiveness of motor performance by dark- versus light-eyed individuals. Dark-eyed individuals generally perform better at reactive type tasks (boxing, hitting a ball, defensive positions in football, rotary pursuit), while light-eyed individuals perform better at self-paced tasks (bowling, golf, pitching baseballs). Subjects performed two tasks, rotary pursuit and ball tossing (with light and dark background). Eye color (light or dark) and accuracy of performance were recorded for each subject. No significant difference was found between eye color and performance on the pursuit rotor (reactive activity). A significant difference was found between men's and women's performance in throwing a ball (self-paced activity) at a light-colored background.

Adult↗
PubMed1992

Expression and purification of the alpha and beta subunits of Drosophila casein kinase II using a baculovirus vector.

Two recombinant baculoviruses that express the alpha and beta subunits of Drosophila melanogaster casein kinase II, respectively, have been constructed. The expressed proteins are similar to the authentic Drosophila subunits in size and are recognized by antisera raised against the Drosophila holoenzyme. Extracts derived from cells infected with the alpha subunit-expressing virus display elevated casein kinase II activity in vitro. This activity is markedly enhanced in extracts of cells infected with both viruses, or when alpha and beta subunit-containing extracts are mixed in vitro following lysis. Recombinant holoenzyme and the alpha subunit were purified to near homogeneity using phosphocellulose column chromatography. The specific activity of the purified recombinant holoenzyme was very similar to that of the native enzyme, and was fivefold higher than that of the purified free alpha subunit. The Stokes radius of the recombinant holoenzyme was estimated to be 50 A, a value similar to that reported for the native enzyme, whereas the alpha subunit demonstrated a Stokes radius of 26.5 A. Studies using sucrose density gradient centrifugation showed that, under conditions of high ionic strength, the quaternary structure of the purified holoenzyme was tetrameric (like the native enzyme), whereas the structure of the alpha subunit was monomeric. At lower ionic strength the recombinant holoenzyme had a significantly higher sedimentation coefficient, characteristic of the formation of filaments found for the native enzyme. Interestingly, the purified catalytic subunit also displayed a higher S value under conditions of low ionic strength, revealing the formation of alpha subunit aggregates.

Animals↗
PubMed1992

Standards for selected anthropometric measurements in males with the fragile X syndrome.

Standards (95th, 50th, and 5th percentiles) in fragile X syndrome for weight, height, head circumference, ear length, and testicular volume are reported. For comparison with fragile X syndrome standardized curves, normal control data from the literature were similarly plotted and curves produced. These standards reflect the physical parameters that are frequently abnormal in males with the fragile X syndrome and should be useful in the medical management of patients with this syndrome. The standards may also be used to help identify those individuals, particularly the younger males, for chromosome studies to confirm the clinical impression of the fragile X syndrome.

Adolescent↗
PubMed1991

Prevention of apoptosis by a baculovirus gene during infection of insect cells.

Programmed cell death is an active process of self destruction that is important in both the development and maintenance of multicellular animals. The molecular mechanisms controlling activation or suppression of programmed cell death are largely unknown. Apoptosis, a morphologically and biochemically defined type of programmed cell death commonly seen in vertebrates, was found to be initiated during baculovirus replication in insect cells. A specific viral gene product, p35, was identified as being responsible for blocking the apoptotic response. Identification of the function of this gene will allow further definition of the molecular pathways involved in the regulation of programmed cell death and may identify the role of apoptosis in invertebrate viral defense systems.

Amino Acid Sequence↗
PubMed1991

Insect paralysis by baculovirus-mediated expression of a mite neurotoxin gene.

Female mites of the species Pyemotes tritici inject an extremely potent venom into their insect prey that causes muscle-contraction and paralysis. These mites are able to paralyse insects 150,000 times their size and their venom is effective in a broad range of insect species. A toxin (TxP-I) associated with the mite venom apparatus causes immediate muscle-contractive paralysis when injected into insects but not mice. In this report, we describe the cloning, sequencing and expression of a complementary DNA (Tox-34) encoding TxP-I. Insect cells infected with a recombinant baculovirus (vEV-Tox34) expressing Tox-34 secrete three polypeptides related to TxP-I which cause paralysis on injection. Larvae infected with vEV-Tox34 become paralysed during infection, thus reflecting the potential application of this toxin gene in insect biocontrol methods. The toxin gene expression system will also allow further exploration of the neurophysiological basis of its insect-specific effects.

Amino Acid Sequence↗
PubMed1991

A baculovirus homolog of a Cu/Zn superoxide dismutase gene.

A gene with greater than 50% amino acid sequence identity to eukaryotic Cu/Zn superoxide dismutase genes (sod) was found at 19 map units in the genome of the baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV). This gene was transcribed into 1.4- and 1.5-kb RNAs late in virus infection. The two late RNAs have coterminal 3' ends but initiate from two different start points, both of which map to the central adenine of the sequence motif ATTAAG. The late gene product was found to be a low abundance 20-kDa polypeptide which was observed only upon partial purification by chloroform/ethanol extraction. Viruses with mutations in sod were able to replicate normally both in cell culture and in insect larvae. Viruses lacking an intact sod showed no evidence of a replication disadvantage even in the presence of paraquat, an inducer of superoxide anions. A viral-encoded superoxide dismutase (SOD) activity was not detected although endogenous insect SODs appeared to be induced in insect hemolymph and in other tissues following virus infection. The function of sod in the baculovirus infection process remains unclear.

Amino Acid Sequence↗
PubMed1991

Baculovirus vectors for multiple gene expression and for occluded virus production.

The nature and properties of a variety of plasmids are described that facilitate the construction of baculovirus vectors for expression of one or more heterologous genes. The plasmids are designed for use with Autographa californica nuclear polyhedrosis virus, AcMNPV, as a vector for protein production in insect cells and/or insect larvae. Several plasmids described here facilitate the simultaneous insertion and expression of two different genes. Some vector systems allow high and equal levels of transcription of both genes while others employ two different promoters for differential transcription. Four of the plasmids described here are designed for expression of both the viral polyhedrin-encoding gene and a heterologous gene. Such recombinants form polyhedral occlusion bodies which serve as visible markers of recombination and facilitate oral infection of insect larvae for mass-scale protein production. A synthetic promoter with a unique sequence can be used at a variety of sites in the viral genome and avoids sequence duplication. A series of plasmids are also described that supply an N terminus with an efficient translational initiation signal and convenient multiple cloning sites in the three different translational reading frames. The modular nature of all the constructs allows the use of other promoters with different temporal regulation to be utilized in the construction of additional plasmids for customized expression work.

Animals↗
PubMed1991

The influence of antisense RNA on transcriptional mapping of the 5' terminus of a baculovirus RNA.

S1 nuclease protection and primer extension analyses were used to determine the 5' end of the Autographa californica nuclear polyhedrosis virus 603 open reading frame (ORF) transcript upstream of and on the opposite strand to the polyhedrin gene. These analyses suggested that the 5' end of the 603 ORF was located near the initiation site for polyhedrin gene transcription. Primer extension products of reverse transcription of 603 RNA were dependent on the presence of the TAAG sequence, an essential polyhedrin promoter element. The results could be interpreted as indicating bidirectional transcription from the TAAG element. However, the data could also be due to an artefact of antisense transcripts and RNA duplex formation in this region. Since the bidirectional transcriptional model is not consistent with other mapping data and Northern blot analysis, we conclude that the presence of antisense RNA can result in mapping artefacts and that caution must be taken in interpreting data where overlapping sense and antisense RNAs are present.

Animals↗
PubMed1991

Musical aptitudes, musical interests and mental retardation.

A modified version of the Bentley scales of musical aptitude was given to a sample of mild and moderately retarded adults chosen on the basis of alleged musical interest or experience. Several comparison groups were also given the assessment battery. The musical nominees generally performed more accurately than both matched retarded subjects with no particular musical interests and a group of normal children matched on (Wechsler) vocabulary scores. The musical nominees showed especially high performance on the subtest assessing voice analysis in chords.

Adult↗
PubMed1991

Participatory management: Maintaining staff performance in a university housing cooperative.

To apply behavior analysis to normal adults in non institutional settings, we may have to encourage their participation in the design and implementation of behavioral technology. This study evaluates a technology by which the members of a student housing cooperative manage their own staff with a minimum of supervision by one of the program designers. This staff management system consisted of prompts, self-reports, spot checks, and contingent rent reductions. Six resident staff members performed substantially more of their assigned tasks when this system was used. In addition, the management system was acceptable to the members, was affordable, and maintained high levels of staff performance during a 5-year follow-up. Participation by the members in the design and implementation of this system appears to have been useful in helping the behavior analysts to develop an unusually durable management system.

Journal Article↗
PubMed1991

A technology for program maintenance: programming key researcher behaviors in a student housing cooperative.

Behavioral researchers play critical, but often unanalyzed, roles in the programs they develop. Unless they replace their key activities with standardized procedures, their continued participation may be essential to program success--a situation that is often not only impractical but may be prohibitively expensive and disliked by local staff. This study was conducted in a student housing cooperative that is dependent on close researcher supervision for its continued health and survival. A key activity of the co-op researchers was to provide public recognition for good job performance by co-op members. The purposes of this study were (a) to replace that idiosyncratic recognition with systematic procedures so members, instead of the researchers, would provide public recognition to each other for good job performance; and (b) to evaluate those procedures by comparing job performance when member-delivered recognition was provided and when it was not. When the procedures were in place, job performance increased and fines for poor job performance and complaining at meetings decreased. This study suggests that procedures can be developed to reduce program reliance on the researcher that are effective, inexpensive, sustainable, and acceptable to the participants--a first step toward developing a technology of program maintenance.

Activities of Daily Living↗
PubMed1991

Assessment of musical aptitude in people with mental disabilities.

Although there has been a long history of attributing different types and degrees of musical sensitivity to individuals with handicaps, actual documentation of the distribution and nature of musical aptitude is sparse. There is almost no normative information about the relative importance of various personal characteristics associated with disability, such as diagnostic category. We also know little about the relative aptitude for different musical components, especially melody and harmony. Directions for future research were suggested.

Achievement↗
PubMed1990

Differential gene expression mediated by late, very late and hybrid baculovirus promoters.

A series of recombinant viruses was constructed to study the regulation of expression from the promoter (Pcap) for the major capsid-protein-encoding gene (vp39) of the baculovirus, Autographa californica nuclear polyhedrosis virus. Each virus of this series contains the cat reporter gene under the control of Pcap or portions thereof. Pcap regulation of cat was determined at the RNA and enzyme activity levels, and was compared to cat gene expression driven by Ppolh, the promoter of the polyhedrin gene (polh). Although optimum expression was achieved with a 464-bp region, which included all three Pcap transcription start points (tsp), a 99-bp segment of Pcap containing a single tsp was sufficient to direct late cat expression. Ppolh and Pcap-mediated regulation differed temporally; Pcap-cat constructs were expressed at 12 h post-infection (p.i.) and continued through 48 h p.i., whereas Ppolh-cat were not expressed at 12 h, but were initiated around 18 h p.i. and underwent a burst of expression between 24 and 48 h p.i. A recombinant virus carrying a hybrid and polh promoter (Pcappolh) was also constructed and studied; Pcappolh contained the two distal tsp of Pcap and a proximal tsp of Ppolh. Pcappolh exhibited both 'late' and 'very late' regulation; the distal tsp were regulated as late sites and the proximal tsp was regulated primarily as a very late site although it also showed a weak late response. Hybrid late/very late promoters should prove useful in optimizing foreign gene expression using baculovirus vectors.

Animals↗
PubMed1990

Rapid transformation of [3H]cholesteryl ester in rat high-density lipoprotein: in vivo and in vitro studies.

[24,25-3H]Cholesteryl ester-labeled rat high-density and low-density lipoproteins were administered to recipient rats. Following death of the rats, a major portion of the radioactivity in administered [3H]cholesteryl ester-high-density lipoprotein rapidly appeared in less dense [3H]cholesteryl ester-lipoproteins and was isolated with the low-density lipoprotein fraction. The specific activity of the esterified cholesterol in the product lipoproteins found with the low-density lipoproteins exceeded that of the precursor high-density lipoproteins. In vitro, the addition of [3H]cholesteryl ester-high-density lipoprotein to plasma resulted in a five- to six-fold increase in radioactivity recovered in the low-density lipoprotein. These results demonstrate that, under a variety of experimental conditions, isolated high-density lipoprotein particles (both in vitro and in vivo) tend to become larger and less dense. Rapid changes in the density of lipoproteins labeled with [3H]cholesteryl ester must be considered when interpreting physiologic studies using this label.

Animals↗
PubMed1990

Androgen binding to ammonium sulfate precipitates of human adipose tissue cytosols.

Although androgens are believed to influence the distribution of human adipose tissue and have been detected in human fat, receptors for these sex hormones have yet to be identified. These studies demonstrate that a high-affinity, limited-capacity binding component for the synthetic androgen methyltrienolone (R1881) exists in ammonium sulfate precipitates of human adipose tissue cytosols. The equilibrium dissociation constant (Kd = 0.1 to 0.4 nmol/L, n = 6) and the number of binding sites (2 to 26 fmol/mg protein, n = 22) are consistent with those reported for androgen receptors in rat prostate, human prostatic carcinoma, MCF-7 cells, and baboon myocardium. The relative steroid-binding specificities of the human adipose tissue androphile (R1881 approximately 5 alpha-dihydrotestosterone greater than testosterone greater than estradiol approximately progesterone much greater than dexamethasone) are similar, but not identical, to those reported for androgen receptors in rat prostate (R1881 greater than 5 alpha-dihydrotestosterone approximately testosterone greater than estradiol greater than progesterone much greater than cortisol) and baboon myocardium (R1881 greater than 5 alpha-dihydrotestosterone greater than testosterone greater than progesterone greater than estradiol much greater than cortisol). The function of the androgen-binding component in human adipose tissue is not known.

Adipose Tissue↗
PubMed1990

Characterization of the DA26 gene in a hypervariable region of the Autographa californica nuclear polyhedrosis virus genome.

A region of the baculovirus Autographa californica nuclear polyhedrosis virus genome that is frequently found to be altered after serial passage of the virus in cell culture was characterized. Sequence analysis of this region of the genome in wild-type and mutant viruses revealed that some of the mutations affected a 675 bp open reading frame, designated DA26. The DA26 gene was disrupted both by deletion and by insertion of sequences that resembled transposable elements. Northern blot analysis of DA26 showed that it was expressed very early after infection. DA26-specific transcripts could be detected after the 1 h viral adsorption period upon infection of cultured Trichoplusia ni cells. These transcripts were mapped by nuclease protection assays. A recombinant virus was constructed in which DA26 was disrupted by insertion of the Escherichia coli lacZ gene. This virus was viable in both T. ni and Spodoptera frugiperda cells and analysis of the kinetics of protein synthesis revealed no differences between wild-type and recombinant viruses. The disruption of DA26 also did not interfere with the ability of the virus to infect T. ni or S. frugiperda larvae.

Amino Acid Sequence↗