Biomedical subjects

K J Miller

Publications and source records attributed to K J Miller.

At least 55 records · Page 3Linked to original sources

PubMed1995

Cooperative conversations. The effect of cooperative learning on conversational interaction.

An ongoing challenge for educators of deaf and hard-of-hearing students is to find opportunities for students to use their language skills in a functional way, that is, through conversation. This study was initiated to determine whether cooperative learning is a viable means of encouraging mainstreamed hard-of-hearing students to engage in conversational interaction with their hearing peers and teachers. A single-subject design utilizing three mainstreamed hard-of-hearing subjects attending middle school was used to examine this question. Results of the study indicated that cooperative learning positively influenced the conversational turns, initiations, moves, and mean length of turn in these hard-of-hearing subjects.

Adolescent↗

PubMed1994

Adenosine A3 receptors regulate serotonin transport via nitric oxide and cGMP.

Many antidepressants inhibit 5-hydroxytryptamine (5HT) transport resulting in increased 5HT levels in the synapse. However, physiological regulation of neurotransmitter uptake has not been demonstrated. We have examined the effect of receptor-activated second messengers on the 5HT transporter in rat basophilic leukemia cells (RBL 2H3). Here, we show that activation of an A3 adenosine receptor results in an increase of 5HT uptake in RBL cells, due to an increase in maximum velocity (Vmax). The A3 adenosine receptor-stimulated increase in transport is blocked by inhibitors of nitric oxide synthase and by a cGMP-dependent kinase inhibitor. In fact, compounds that generate nitric oxide (NO) and the cGMP analog 8-bromo-cGMP mimicked the effect of A3 receptor stimulation, suggesting that the elevation in transport occurs through the generation of the gaseous second messenger NO and a subsequent elevation in cGMP. Additionally, the 5HT transporter is differentially regulated by second messengers since direct activation of protein kinase C by phorbol esters decreases 5HT uptake by decreasing Vmax. Our results suggest that the changes in transport are due to a direct modification of the 5HT transporter, possibly by phosphorylation, which appears to alter the rate at which transport occurs. As the 5HT transporter in RBL cells is identical to that in neurons, our results suggest that analogous mechanisms may operate in the brain.

Adenosine↗

PubMed1994

Enzymatic profiling of immobilized cells using CZE.

Baker's yeast cells (Saccharomyces cerevisiae) were immobilized on a CZE capillary using a midcapillary frit of novel design. The frit was constructed using a single 50-microns particle with "through pores". Cells trapped on the capillary were profiled using different amino acid beta-naphthylamide-aminopeptidase substrates. These substrates were introduced sequentially and metabolized for 1 min. After incubation the hydrolysis products were withdrawn by electrophoresis and detected by laser-induced fluorescence. An aminopeptidase profile was produced using just 500 cells. The new CZE-based method was found to have several significant advantages over the older cuvette/fluorometer method.

Electrophoresis↗

PubMed1994

Attrition from conjoint alcoholism treatment: do dropouts differ from completers?

This study addresses patient attrition in order to identify variables associated with retention in conjoint treatment for alcohol abuse and dependence. Subjects were 105 male alcoholics and their partners who participated in a randomized clinical trial of three approaches to conjoint treatment of alcoholism: (a) alcohol and behavioral marital therapy (ABMT); (b) ABMT plus Alcoholics Anonymous and Alanon (AA/ABMT); and (c) ABMT plus relapse prevention (RP/ABMT). Completers (n = 45) attended two assessment and 15-17 treatment sessions. Partial completers (n = 23) left treatment between the 5th and 15th treatment session. Thirty-seven dropouts left treatment between the first assessment session and the 5th treatment session; of these, 22 dropouts completed at least one treatment session (called early treatment dropouts). Of subjects who entered treatment, dropouts from early treatment were least compliant with treatment requirements in the first few sessions, less educated, and less committed to their relationship. Data indicate that therapists with more clinical experience were more likely to retain clients in treatment, regardless of treatment condition. The data do not reflect a linear relationship between most variables studied and a continuum of attrition status from assessment to completion of the program.

Adult↗

PubMed1994

Synthesis of glycerophosphorylated cyclic beta-(1,2)-glucans by Rhizobium meliloti ndv mutants.

The periplasmic cyclic beta-(1,2)-glucans of Rhizobium spp. are believed to provide functions during hypoosmotic adaptation and legume nodulation. In Rhizobium meliloti, cyclic beta-(1,2)-glucans are synthesized at highest levels when cells are grown at low osmolarity, and a considerable fraction (> or = 35%) of these glucans may become substituted with phosphoglycerol moieties. Thus far, two chromosomally encoded proteins, NdvA and NdvB, have been shown to function during cyclic beta-(1,2)-glucan biosynthesis; however, the precise roles for these proteins remain unclear. In the present study, we show that R. meliloti mutants lacking up to one-third of the downstream region of ndvB synthesize cyclic beta-(1,2)-glucans similar to those produced by wild-type cells with respect to size and phosphoglycerol substituent profile. In contrast, no phosphoglycerol substituents were detected on the cyclic beta-(1,2)-glucans synthesized by an R. meliloti ndvA mutant.

ATP-Binding Cassette Transporters↗

PubMed1994

Cyclic beta-glucans of members of the family Rhizobiaceae.

Cyclic beta-glucans are low-molecular-weight cell surface carbohydrates that are found almost exclusively in bacteria of the Rhizobiaceae family. These glucans are major cellular constituents, and under certain culture conditions their levels may reach up to 20% of the total cellular dry weight. In Agrobacterium and Rhizobium species, these molecules contain between 17 and 40 glucose residues linked solely by beta-(1,2) glycosidic bonds. In Bradyrhizobium species, the cyclic beta-glucans are smaller (10 to 13 glucose residues) and contain glucose linked by both beta-(1,6) and beta-(1,3) glycosidic bonds. In some rhizobial strains, the cyclic beta-glucans are unsubstituted, whereas in other rhizobia these molecules may become highly substituted with moieties such as sn-1-phosphoglycerol. To date, two genetic loci specifically associated with cyclic beta-glucan biosynthesis have been identified in Rhizobium (ndvA and ndvB) and Agrobacterium (chvA and chvB) species. Mutants with mutations at these loci have been shown to be impaired in their ability to grow in hypoosmotic media, have numerous alterations in their cell surface properties, and are also impaired in their ability to infect plants. The present review will examine the structure and occurrence of the cyclic beta-glucans in a variety of species of the Rhizobiaceae. The possible functions of these unique molecules in the free-living bacteria as well as during plant infection will be discussed.

ATP-Binding Cassette Transporters↗

PubMed1994

Itinerant teachers. Responsibilities, perceptions, preparation, and students served.

Increased numbers of deaf and hard of hearing students live at home, attend their neighborhood schools, and receive major portions of their educations from general education teachers with support from itinerant teachers of deaf and hard of hearing students. Although the itinerant service-delivery model is used extensively, there is a paucity both of information about itinerant teaching and of research that has examined its effectiveness. The purpose of this study was to begin a database of information about the job responsibilities, perceptions, and preparation of itinerant teachers, as well as about the characteristics of the students they serve. Data from surveys returned by 319 itinerant teachers was analyzed. The responses indicate that itinerant teaching differs in numerous ways from more-traditional approaches to educating deaf and hard of hearing students. Results, implications, concerns, and suggestions for future research are discussed.

Adult↗

PubMed1993

Electrophoretically mediated microanalysis of leucine aminopeptidase in complex matrices using time-resolved laser-induced fluorescence detection.

Leucine aminopeptidase, a clinically significant enzyme, was assayed in complex biological samples using a new technique termed electrophoretically mediated microanalysis. The assay was performed in capillary electrophoresis columns using time-resolved laser-induced fluorescence detection. Human serum, human urine, and Escherichia coli supernatant samples were assayed using this method. Results for serum and urine were within the ranges of expected values found in the literature. A low concentration of 6 x 10(-13) M enzyme in buffer was detected using this method. A detection limit (3 sigma) of 400 enzyme molecules in buffer was determined.

Buffers↗

PubMed1993

Evaluation of local anesthesia provided by transdermal patches containing different formulations of tetracaine.

Topical formulations of tetracaine in vehicles of propylene glycol and saline are tested on human volunteers with standard occlusive, adhesive, transdermal patches. The effects of formulation composition, dose, and onset time are investigated. Dose-response studies indicate that the optimum formulation for the diffusion of tetracaine in vivo is 60% free base and 40% acid salt (w/w) in 40% propylene glycol and 60% saline (v/v). A concentration of 0.3 M [8.3% (w/v)] tetracaine is sufficient to reach the dose plateau. Time-response studies indicate that high concentrations of tetracaine in the optimum formulation [1.1 and 1.8 M, 30 and 50% (w/v), respectively] can produce statistically significant analgesia relative to a placebo after 45 min. Comparison of these in vivo data with earlier in vitro data indicate that the optimum formulation with regard to clinical studies is identical to that for in vitro diffusion through hairless mouse skin [60% free base and 40% acid salt (w/w) in 40% propylene glycol and 60% saline].

Administration, Cutaneous↗

PubMed1993

Identification of a high-affinity glycine betaine transport system in Staphylococcus aureus.

Staphylococcus aureus accumulates proline and glycine betaine when cells are grown at low water activity. In the present study, we have identified a high-affinity glycine betaine transport system in this bacterium. Optimal activity for this transport system was measured in the presence of high NaCl concentrations, but transport activity was not stimulated by high concentrations of other solutes.

Betaine↗

PubMed1992

Agonist activity of sumatriptan and metergoline at the human 5-HT1D beta receptor: further evidence for a role of the 5-HT1D receptor in the action of sumatriptan.

We have recently cloned a novel human 5-HT1D receptor subtype termed 5-HT1D beta. CHO K1 cells expressing the human serotonin 5-HT1D beta receptor were assayed to determine the second messenger system of this receptor. Cyclic AMP radioimmunoassays revealed that the 5-HT1D beta receptor is negatively coupled to adenylate cyclase in this cell system. A maximum of 50% inhibition of forskolin stimulated cAMP production was obtained with 5-HT1 receptor agonists which was blocked by the non-selective 5-HT receptor antagonist methiothepin (pKB = 100 nM). The novel anti-migraine drug sumatriptan, a putative 5-HT1D selective compound, acted as an agonist at the 5-HT1D beta receptor. Most notably metergoline, a putative 5-HT1 receptor antagonist, did not block the effects of 5-HT and was found to be acting as a full agonist at the 5-HT1D beta receptor. The ability of metergoline to act as an agonist at the 5-HT1D beta receptor may explain why it does not inhibit 5-HT and sumatriptan induced contraction of dog saphenous vein and other large conducting arteries. These results suggest that the 5-HT1D beta receptor may be the site of action of sumatriptan in preventing migraine, and that metergoline's actions on the dog saphenous vein are not contradictory to that hypothesis, as previously reported.

Cells, Cultured↗

PubMed1992

Asymmetric elevation of striatal dopamine D2 receptors in the chakragati mouse: neurobehavioral dysfunction in a transgenic insertional mutant.

We have previously reported the discovery of a transgenic insertional mutant, recently named the chakragati (ckr) mouse, which displays lateralized circling, locomotor hyperactivity, hyperreactivity, as well as body weight deficits. Since lateralized dopamine function is associated with circling behavior we sought to determine whether dopamine (DA) D1 and D2 receptors were asymmetrically distributed in the striata of adolescent and adult ckr mice using receptor autoradiography. Stereotypic and rotational responses to quinpirole served as behavioral indices of D2 receptor function. The ckr mice showed hemispherically asymmetric elevations in DA D2 receptors in the lateral subregions of the striatum whereas medial regions of the striatum were symmetrically and bilaterally elevated (overall elevation = 30%). As a group, ckr mice had higher D2 receptor levels on the side which was contralateral to the preferred direction of spontaneous nocturnal rotation. Striatal D1 receptors and mesolimbic D2 and D1 receptors of ckr mice were neither elevated nor differentially asymmetric. Young adult ckr mice showed dose-dependent increases in net rotations in response to quinpirole whereas normal mice showed no change from baseline levels. Both groups showed similar stereotypic responses. Older adult ckr mice, however, showed dose-dependent reductions in rotation after quinpirole whereas normal mice turned at baseline levels. Older ckr mice also displayed significantly greater stereotyped sniffing behavior. This unique mutant provides a novel genetic model of basal ganglia dysfunction, and may be useful in studying aspects of neuropsychiatric disorders associated with dopaminergic abnormalities.

Animals↗

PubMed1992

Quantitative autoradiography of 5-CT-sensitive (5-HT1D) and 5-CT-insensitive (5-HT1E) serotonin receptors in human brain.

Quantitative receptor autoradiography was used to determine the distribution patterns of 5-CT-sensitive and 5-CT-insensitive binding of [3H]5-HT to high-affinity sites in human cortex, putamen, and globus pallidus. The binding of 3H-5-HT was limited to 5-HT1D sites (5-CT-sensitive) by co-incubating pindolol and mesulergine with [3H]5-HT, and by using 10 microM 5-HT to determine non-specific binding. The difference in the levels of binding between tissues exposed to the 5-CT-containing incubation media and tissue exposed to [3H]5-HT in the presence of 100 nM 5-CT was defined as 5-CT-insensitive binding (5-HT1E). The 5-HT1D receptor density in the frontal cortex was 189 fmol/mg, 226 fmol/mg was present in the globus pallidus, while the density in the putamen was only 28 fmol/mg. The 5-HT1E receptor density was 146 fmol/mg in frontal cortex, 224 fmol/mg in putamen and 140 fmol/mg in globus pallidus. The differential distribution patterns of the high-affinity, 5-CT-sensitive and 5-CT-insensitive [3H]5-HT binding sites indicate that these sites are expressed independently in human brain tissues. These data are supportive of and consistent with previous pharmacological data that led to the division of 5-HT1D receptors into 5-HT1D and 5-HT1E receptors and do not support the division of 5-HT1D receptors into 5-CT-sensitive and 5-CT-insensitive states.

Antiparkinson Agents↗

PubMed1992

Identification of two proline transport systems in Staphylococcus aureus and their possible roles in osmoregulation.

The food-borne pathogen Staphylococcus aureus is distinguished from other food-borne pathogens by its ability to grow at water activity values below 0.90. Previous studies have indicated that proline accumulation mediated by transport represents a primary osmoregulatory strategy utilized by this bacterium (C. B. Anderson and L. D. Witter, Appl. Environ, Microbiol. 43:1501-1503, 1982; I. Koujima, H. Hayashi, K. Tomochika, A. Okabe, and Y. Kanemasa, Appl. Environ. Microbiol. 35:467-470, 1978; K. J. Miller, S. C. Zelt, and J.-H. Bae, Curr. Microbiol. 23:131-137, 1991). In this study, we demonstrate the presence of two proline transport systems within whole cells of S. aureus, a high-affinity transport system (Km, 7 microM) and a low-affinity transport system (Km, 420 microM). Our results indicate that the low-affinity proline transport system is osmotically activated and is the primary system responsible for the accumulation of proline by this pathogen during growth at low water activity.

Betaine↗

PubMed1992

Cloning, expression, and nucleotide sequence of a lipase gene from Pseudomonas fluorescens B52.

In this study, we report the cloning and expression of lipase gene from Pseudomonas fluorescens B52, a psychrotrophic spoilage bacterium isolated from refrigerated raw milk. Sequence analysis revealed one major open reading frame of 1,428 nucleotides that was predicted to encode a protein with a molecular weight of 50,241. The predicted enzyme was found to contain an amino acid sequence highly homologous to the putative substrate-binding domain present within all lipases examined to date.

Amino Acid Sequence↗

PubMed1992

Cell surface carbohydrates of microaerobic, nitrogenase-active, continuous cultures of Bradyrhizobium sp. strain 32H1.

A continuous culture system was developed to examine the cell surface carbohydrates of Bradyrhizobium sp. strain 32H1. When cultures were shifted from aerobic to microaerobic growth conditions, nitrogenase activity was induced and extracellular polysaccharide levels were greatly reduced; however, the levels of cell-associated cyclic beta-1,6 -1,3 glucans were found to be essentially unchanged.

Aerobiosis↗

PubMed1992

Let's talk about it. Using conversation to facilitate language development.

For centuries, educators have searched for the best way to teach language to deaf students. Throughout this time period, no one specific approach has emerged. In this article, we examine and justify the use of conversational approaches to teach language to deaf students. Classrooms for deaf students are often not conducive to conversation. We suggest that to promote conversation in classrooms, teachers must reexamine how they teach as well as how they structure their classrooms and curriculums. The article closes with descriptions of activities that teachers can use to encourage conversation in their classrooms.

Adolescent↗

PubMed1991

Ontogeny of hyperactivity and circling behavior in a transgenic insertional mutant mouse.

In a previous study (Ratty et al., 1990), the discovery of a transgenic mutant mouse that displayed abnormal circling behavior was reported. Mice homozygous for the transgene display this phenotype, whereas heterozygotes are phenotypically normal. In this study, circling mutants displayed excessive lateralized circling behavior and locomotor hyperactivity by Postnatal Days (PND) 14 and 16, respectively. These abnormalities persisted unattenuated through adolescence and adulthood. Disturbances in rearing and grooming were also observed in circling mutants. Surface-righting ability in the mutants was normal, and the age of eye opening was only marginally delayed. However, body weights of the mutants were reduced compared with normal mice from PND 15 to adulthood. Possible relationships between the behaviors that are exhibited by circling mutants and previous neurochemical findings are discussed.

Age Factors↗