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Biomedical subjects

L K Miller

Publications and source records attributed to L K Miller.

At least 19 recordsLinked to original sources

HIV-associated oral lesions; immunologic, virologic and salivary parameters.

There are numerous reports of oral lesions in HIV-infected individuals. However, few correlate the oral lesions with laboratory parameters. This study examined oral candidiasis and hairy leukoplakia, the two most common HIV-associated oral lesions, in relation to T-cell counts, p24 core antigen levels and salivary flow rates. Oral mucosal examinations, immunologic and virologic studies and stimulated whole and parotid saliva flow rates were conducted on 135 (HIV+ = 102, HIV- = 33) homosexual or bisexual men. Results indicate that, among HIV-infected subjects, the odds of having oral candidiasis is 6 times (95% CI = 0.6-56.6) greater for subjects with T4 counts between 200-399 per mm3, and 23 times (95% CI = 2.8-193.0) greater for subjects with T4 counts less than 200/mm3 compared to subjects with T4 counts of 400/mm3 or greater. Subjects had an equal likelihood of having hairy leukoplakia at different levels of immunocompetence. The prevalence of oral candidiasis and hairy leukoplakia was higher among subjects with infectious virus in their serum, but was only statistically significant for hairy leukoplakia (p = 0.01).

Adult

Insecticidal properties of genetically engineered baculoviruses expressing an insect juvenile hormone esterase gene.

Exploring the possibility of enhancing the properties of baculoviruses as biological control agents of insect pests, we tested the effect of expressing an insect gene (jhe) encoding juvenile hormone esterase. Juvenile hormone esterase inactivates juvenile hormone, which regulates the outcome of an insect molt. A cDNA encoding the juvenile hormone esterase of Heliothis virescens was inserted into the genome of Autographa californica nuclear polyhedrosis virus such that the gene was expressed under the control of a strong, modified viral promoter. This virus, however, naturally encodes an ecdysteroid UDP-glucosyltransferase which inactivates ecdysone, the hormone which initiates molting. Since ecdysteroid UDP-glucosyltransferase could mask the effects of jhe expression by blocking molting entirely, jhe-expressing viruses in which the ecdysteroid UDP-glucosyltransferase gene was deleted or disrupted were constructed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of proteins from infected cells revealed several intracellular proteins and two major secreted proteins which reacted with antibodies to authentic juvenile hormone esterase. Western blot analysis coupled with tunicamycin treatment indicated that differential glycosylation was responsible for the multiple products. Hemolymph of recombinant virus-infected fourth-instar Trichoplusia ni larvae contained levels of juvenile hormone esterase activity 40-fold higher than maximal levels found in uninfected larvae. However, little or no difference in developmental characteristics, weight gain, or time of mortality was observed between insects infected with the jhe-expressing viruses and control viruses.

Animals

Characterization of a baculovirus gene encoding a small conotoxinlike polypeptide.

We identified a gene of Autographa californica nuclear polyhedrosis virus (AcMNPV) that encodes a small cysteine-rich polypeptide which has size and sequence similarity to omega-conotoxins, a class of calcium ion (Ca2+) channel inhibitors, found in the venom of cone snails. Transcriptional analysis indicated that the 159-bp open reading frame, which we named ctl, and a downstream 984-bp open reading frame are transcribed as a single 1.3-kb bicistronic late RNA. The mature ctl gene product was identified as a small secreted protein by high-pressure liquid chromatography fractionation of extracellular fluid. Viruses with a site-specific deletion in ctl appeared normal with regard to the kinetics and virulence of infection, both in vitro and in vivo. Although we studied the behavior of wild-type and mutant virus-infected insects in some detail, a biological role for ctl in AcMNPV infection remains to be established.

Amino Acid Sequence

Promoter influence on baculovirus-mediated gene expression in permissive and nonpermissive insect cell lines.

The activities of viral and insect promoters were examined in a range of insect cell lines permissive and nonpermissive for the replication of the baculovirus Autographa californica nuclear polyhedrosis virus. Recombinant baculoviruses were constructed to place the bacterial chloramphenicol acetyltransferase gene under the control of promoters strongly active in the early, late, or very late stages of virus replication. In fully permissive cells, expression from a very late promoter was 2- to 3-fold higher than expression from a late promoter and 10- to 20-fold higher than expression from an early promoter or from a virus-borne insect promoter. In cell lines that do not support the efficient production of viral progeny, late-promoter-driven expression was similar to or surpassed very late promoter-driven expression. In nonpermissive insect cell lines, expression driven by an insect promoter derived from Drosophila melanogaster was higher than expression from the three viral promoters and was especially high in the Drosophila cell line tested. Surprisingly, late-promoter-driven expression, which is dependent on DNA replication, was higher than early-promoter-driven expression in three of four nonpermissive lines. In contrast, very late promoter-driven expression was quite limited in nonpermissive cell lines. The results indicate that the promoter used to drive foreign-gene expression strongly influences the range of insect cells which can efficiently support the production of the foreign protein during infection with recombinant baculoviruses.

Animals

Recovery of infectious HIV-1 from whole saliva.

Whole saliva and serum samples were collected from 75 HIV-infected homosexual or bisexual men. Thirty-eight percent of cultured sera were positive for cell-free, infectious virus while only 1 percent of the 218 cultured whole salivas contained cell-free, infectious virus. These data support previous studies suggesting unlikely potential transmissibility of HIV infection by saliva.

Adult

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

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

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

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

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

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

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

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

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

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

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