A microscope slide probe for high resolution imaging at 11.7 Tesla

We present details of a novel RF coil for use in NMR microscopy. This coil is an inductively coupled surface coil which is built into a standard microscope slide. The coil is highly sensitive and is also designed so that the sample to be imaged can be viewed under an optical microscope. This facility allows comparison of optical and NMR micrographs, as well as accurate sample positioning. Using the slide coil, images of onion epidermal cells with an in-plane resolution of 4.5 microns have been produced.

Modulation of swimming in Tritonia: excitatory and inhibitory effects of serotonin

1. In the mollusc Tritonia escape swimming is produced by a network of central pattern generator (CPG) neurons. The purpose of this study was to determine which neurotransmitters might be involved in the swim system. 2. Injection of serotonin (5HT) into whole animals elicited swimming followed by a long-lasting inhibition of swimming. In isolated brain preparations, bath-applied 5HT elicited a swim pattern at short latency and also caused a long-lasting inhibition of the swim pattern. The activation of swimming by 5HT was associated with a tonic depolarization of cerebral cell 2 (C2) and the dorsal swim interneurons (DSI) which form part of the swim CPG network. 3. In isolated brain preparations, bath applied glycine, histamine, proctolin, and FMFRamide had no effect on the swim motor pattern elicited by electrical stimulation of a peripheral nerve. Aspartate, carbacol, dopamine, glutamate, octopamine, pilocarpine, and small cardioactive peptide-B (SCPB) inhibited the activation of swimming by nerve stimulation. 4. The 5HT antagonists cyproheptidine, tryptamine, and 7-methyltryptamine had no effect on swimming, but methysergide and fenfluramine inhibited swimming to both normal sensory stimuli and exogenously applied 5HT. 5. Staining with a polyclonal antibody indicated that one class of CPG neurons, the dorsal swim interneurons (DSI), was immunoreactive for 5HT.

Accounting for power: nurse teachers' and students' perceptions of power in their relationship

In this paper I examine how nurse teachers and students perceive power to operate within their relationship. Interviews and focus group discussions showed that teachers and their students agreed that power operates within three distinct planes: the educational process, interpersonal relationships and learning outcomes. Common perceptions of power distributions within these planes were also demonstrated. A major difference was found to be in the emphasis accorded to power planes. Teachers related more to educational power while students were more concerned with personal power. I suggest how the findings can be applied to resolve seemingly conflicting teacher/student perceptions of power distribution and discuss how students believe they can best be empowered by teachers.

Short-term memory impairments in Alzheimer-type dementia: evidence for separable impairments of articulatory rehearsal and long-term memory

Two experiments are described which investigate the short-term memory deficits found in Alzheimer-type dementia. In the first experiment memory span for words of differing spoken duration is related to speech rate. Memory span was lower in subjects suffering from Alzheimer-type dementia than for normal elderly controls but in both cases a linear function related recall to speech rate for items of differing spoken durations. The function for Alzheimer subjects had an equivalent slope (interpreted as reflecting a contribution from a sub-vocal rehearsal process) but a lower intercept (interpreted as reflecting a contribution from a long-term memory component). The second experiment investigated the effects of repeating supra-span lists of items in a serial recall task. As predicted the control subjects showed substantial increases in recall across trials associated with elevations of the speech rate/recall functions while the Alzheimer subjects showed very little benefit from repetition of the lists. We conclude that the verbal short-term memory deficit found in Alzheimer-type dementia has two components: a deficit in the rate of rehearsal and an impairment in the long-term memory component of short-term recall.

Quality evaluation of controlled clinical information service trials

Randomized controlled clinical trials are increasingly accepted as tools of computer technology assessment and, therefore, quality evaluation of trials has great theoretical and practical significance. The purpose of this study was to assist the design of evaluation studies and synthesis of published results by developing and validating an easy-to-use quality scoring method. The development of the new scoring system was based on the available quality evaluation methods and the analysis of 19 trial reports registered in the Columbia Registry of Controlled Clinical Information Service Trials. First critical aspects and afterwards the levels of quality were defined. In spite of the fact that all quality requirements were met by some trials, the average overall quality score was 52.6 (+/- 8.7) per cent. The minimum score was 37 and the maximum was 72 per cent. Data collection and site/sample definition were better in the good quality trials, but improvement in statistical analysis was erratic. The quality scoring method was validated by using another sample of 20 registered trials. While the number of published controlled clinical trials is increasing in medical informatics, the analysis was unable to demonstrate a significant positive correlation between the quality and year of publication.

A novel DNA binding activity is elevated in thymocytes expressing high levels of H-2Dd after radiation leukemia virus infection

Resistance to radiation leukemia virus-induced leukemia is mediated by gene(s) in the H-2D region of the MHC; a clear correlation exists between disease resistance and increased H-2Dd expression on the thymocyte surface. We have investigated the molecular basis for this stimulation of H-2Dd class I expression. Elevated H-2 mRNA and H-2 transcription are demonstrated in the infected thymocytes as compared to normal thymocytes indicating that the elevation of H-2 surface expression is the result of transcriptional activation. Gel mobility assays performed with nuclear extracts of normal and infected thymocytes and sequences 5' of the H-2Dd gene show that specific binding occurs with both extracts; the binding differs both quantitatively and qualitatively, however. DNase I protection analysis detects a protein binding site that is protected only by extracts from infected cells. The protected region contains a sequence similar to the AP-1 consensus sequence. Gel shift competition assays and UV photo-cross-linking to an oligonucleotide containing this sequence demonstrate that specific binding of an H-2 binding factor 1 occurs and that this factor is not the AP-1 binding complex. This novel binding factor, activated in vivo, might also be involved in the normal regulation of H-2 gene expression by recognizing the highly conserved binding sequence (TGACGCG) found in the 5' flanking region of many MHC class I genes. This is the first demonstration of the parallel stimulation of a DNA binding activity and increased transcription occurring in thymocytes after infection with a leukemogenic retrovirus.

A novel DNA binding activity is elevated in thymocytes expressing high levels of H-2Dd after radiation leukemia virus infection

Resistance to radiation leukemia virus-induced leukemia is mediated by gene(s) in the H-2D region of the MHC; a clear correlation exists between disease resistance and increased H-2Dd expression on the thymocyte surface. We have investigated the molecular basis for this stimulation of H-2Dd class I expression. Elevated H-2 mRNA and H-2 transcription are demonstrated in the infected thymocytes as compared to normal thymocytes indicating that the elevation of H-2 surface expression is the result of transcriptional activation. Gel mobility assays performed with nuclear extracts of normal and infected thymocytes and sequences 5' of the H-2Dd gene show that specific binding occurs with both extracts; the binding differs both quantitatively and qualitatively, however. DNase I protection analysis detects a protein binding site that is protected only by extracts from infected cells. The protected region contains a sequence similar to the AP-1 consensus sequence. Gel shift competition assays and UV photo-cross-linking to an oligonucleotide containing this sequence demonstrate that specific binding of an H-2 binding factor 1 occurs and that this factor is not the AP-1 binding complex. This novel binding factor, activated in vivo, might also be involved in the normal regulation of H-2 gene expression by recognizing the highly conserved binding sequence (TGACGCG) found in the 5' flanking region of many MHC class I genes. This is the first demonstration of the parallel stimulation of a DNA binding activity and increased transcription occurring in thymocytes after infection with a leukemogenic retrovirus.

The Columbia Registry of Controlled Clinical Computer Trials

Numerous reports on randomized controlled clinical trials of computer-based interventions have been published. These trials provide useful evaluations of the impact of information technology on patient care. Unfortunately, several obstacles make access to the trial reports difficult. Barriers include the large variety of publications in which reports may appear, non-standard descriptors, and incomplete indexing. Some analyzers indicate inadequate testing of computer methods. The purpose of establishing a registry of randomized controlled clinical computer trials was to assist the identification of computer services with demonstrated ability to improve the process or outcome of patient care. A report collection, selection, information extraction, and registration method was developed and implemented. One hundred and six reports on computer trials have been collected. A large variety of computer-assisted interventions have been tested in the registered trials (40% reminder, 15% feedback, 14% dose planning, 14% patient education, 12% medical record). 76% of the registered reports were published in the United States and most of the remainder in various European countries. In reporting computer trial results, 77% of the authors did not use both the "computer" and "trial" keywords in the title or abstract of their papers. We conclude that a major obstacle to adequate computer technology assessment is inadequate access to the published results.

Organizational assessment: concept, method and application

The concept of organizational assessment of health institutions is explored in terms of why it is becoming increasingly popular, alternative approaches, and its potential as a tool for quality assurance or program evaluation. There is an outline of an approach to developing standardized performance criteria and a design for carrying out an assessment through a self-assessment method. Illustrations of the application of the model are included.

In vivo stimulation of H-2Dd expression following RadLV infection of thymocytes: increased transcription and DNA-binding activity to sequences 5' of the Dd gene

Early studies showed that resistance to RadLV-induced leukaemia is mediated by gene(s) in the H-2D region of the MHC. Furthermore, these experiments correlated disease resistance with changes in H-2 expression occurring very early after virus inoculation. In the present study, we have begun to study at the molecular level this stimulation of H-2Dd class I expression in thymocytes of resistant mouse strains following infection by RadLV. The resistant strain of B10.T(6R) mice is used in these studies. When these infected thymocytes are assayed by fluorescence-activated cell sorting analysis, we can detect increased levels of H-2Dd expression on the surface of the thymocytes as early as 12 days following intrathymic injection of RadLV. RNA was prepared and examined by Northern blot analysis; H-2 mRNA levels are shown to be elevated on the order of four-fold. Nuclei were prepared from normal and infected thymocytes and the run-off transcripts were analysed by slot-blot hybridization. The rate of H-2 mRNA transcription is shown to be two- to three-fold higher in RadLV-infected thymocytes at 14 days post-infection when compared to that of normal thymocytes. These data demonstrate that elevation of H-2 surface expression following RadLV infection is the result of transcriptional activation. Extracts have been prepared from both normal and infected B10.T(6R) thymocytes and have been used in gel mobility assays in order to detect the interaction of potential trans-acting regulatory factors with sequences 5' of the H-2Dd gene. Specific binding occurs in both extracts, but the assay shows that the extracts differ both quantitatively and qualitatively; the extracts from infected thymocytes bind to additional sequences and to a higher degree than that from normal thymocytes. DNase I protection analysis locates a number of protein-binding sites, some of which are protected by extracts of either origin and some of which are only protected by extracts from infected cells. Two of these sequences are similar to the previously recognized consensus recognition sequences for the binding of AP-1 and NF-chi B. Oligonucleotides have been synthesized for both the genomic sequences being protected from DNase I digestion as well the published consensus sequences. While the DNA-binding activity in infected thymocytes for both AP-1 and NF-chi B-binding sites is increased, the binding to the genomic "AP-1 like" binding site is activated to a considerably greater level.(ABSTRACT TRUNCATED AT 400 WORDS)

Modeling the functional organization of the basal ganglia. A parallel distributed processing approach

Despite recent advances in the understanding of the pathophysiology of movement disorders, little is known about the precise function the basal ganglia play in the control of movement. We review an approach to studying the function of neural systems that is based on the use of a class of computer models known as parallel distributed processors (PDPs) and indicate its potential range of applications to the study of movement disorders. PDPs can be used to construct computational devices that take into account the anatomical and pharmacological properties of real neural systems. They can also provide computational-level insights that can lead to novel hypotheses concerning brain function. We discuss both these approaches and outline a scheme of the functional organization of the basal ganglia, which predicts some of the pathophysiological mechanisms that mediate movement disorders and which can be formally modeled on a computer.

Increased H-2Dd expression following infection by a molecularly cloned ecotropic MuLV

The biological consequences of radiation leukemia virus (RadLV) infection include the stimulation of H-2Dd antigen expression in resistant mouse strains and thymoma induction in susceptible strains. In an effort to understand the genetic basis of these phenomena, the integrated ecotropic RadLV genome has been examined in a number of primary RadLV-induced tumors, as well as thymomas adapted to in vitro passage; considerable heterogeneity was observed. Examination of these polymorphic viral sequences should help define the viral gene(s) involved in the biological effects of RadLV infection; toward this end, integrated RadLV genomes were molecularly cloned and examined. The genomes and their flanking sequence were characterized by restriction enzyme analysis. Three unique viral genomes were obtained which represent four integration sites. The three RadLV genomes are shown to carry polymorphisms of the original tumor. Following DNA transfection, one of the three genomes replicated in and reinfected both mouse thymocytes and fibroblasts, but not mink fibroblasts in vitro. Virus encoded by the other two DNA genomes could not be recovered following transfection into any of the three cell types. One of these two apparently defective retroviruses encodes a truncated p15E molecule, while the other has elongated long terminal repeats (LTRs). The non-defective ecotropic isolate was collected from in vitro tissue culture supernatants, concentrated, and used to infect mice. Thymocytes of infected, resistant mice were shown to express elevated levels of H-2Dd antigen as early as 12 days post infection, a hallmark of RadLV infection.

Radiation leukemia virus and its effect on H-2 gene expression

In this report we demonstrate that lowered expression of the H-2 antigens on RadLV-induced tumour cells is a result of depressed levels of stable mRNA in these cells. Whether this observation is a result of lowered transcription or of mRNA instability is under investigation. In an effort to determine which viral sequences are essential for mediating both the H-2 regulatory function and the transforming function of RadLV, we have begun to assemble newly integrated proviral genomes from tumours. The restriction enzyme cleavage sites of four isolates are presented; these isolates differ substantially from RadLV genomes previously presented. One of these molecular clones is shown to encode a non-defective B-tropic, ecotropic virus which when reinjected into resistant mouse strains can mediate the up-regulation of H-2Dd antigen expression. Finally, possible mechanisms of H-2 regulation are discussed.

The evaluation of the recovery capacity of media for heat-treated Bacillus stearothermophilus spore strips

Six media were assessed for their capacity to recover spores of Bacillus stearothermophilus from three commercially available types of spore strip heated for up to 5 min at 121 degrees C in steam. All media recovered similar numbers of spores from unheated strips; however, there was considerable difference in survivor counts when the media were used to recover heated spores. Media containing starch consistently recovered the highest number of spores. The greatest difference in recovery capacity between the media was observed when spore strips were heated for 5 min at 121 degrees C.

Extension of the H-2 TLb molecular map. Isolation and characterization of T13, T14, and T15 from the C57BL/6 mouse

A region of the TLb locus encompassing T11 to T13 contains retroviral sequences TLev1 and TLev2. As part of a study to determine whether the retroviral elements are involved in the expression of TL genes, the genomic organization of this region was reexamined in greater detail. A result of these investigations is the extension of the H-2 TLb molecular map. Two additional TL genes have been isolated from C57BL/6 mice, T14 and T15. The genomic organization of T9 through T15 is presented. The nucleotide sequence has been determined for exons 4, 5, and 6 of T13. As a result of a C to T conversion, a termination codon is introduced into exon 4, indicating that T13 either encodes a secreted protein or is a pseudogene. T13 was found to be more homologous to the H-2 genes outside the TL region. T14 has been physically disrupted by the integration of TLev1, and the H-2 sequences appear to have diverged greatly. The relationship of the TL regions of the b and c haplotypes has been investigated using numerous low copy probes. The genome of BALB/c (TLc) is shown to lack a counterpart of the T13-T15b region. Homologous regions exist in the two haplotypes; yet considerable polymorphism is observed. TLb mice do not express TLa on the cell surface of normal thymocytes while TLc mice do; TLa expression is activated in many TLb leukemias. The diversity seen in the T13-T15 region may provide insights into the phenotypic expression or regulatory mechanisms of TL expression in these two haplotypes.

Effects of exercise and anabolic steroids on total and lipoprotein cholesterol concentrations in male and female rats

Forty male and 40 female rats were randomly assigned to 1 of 4 experimental groups. Half of the animals of each gender were exercised by jumping (weighted by a vest with up to 70% body weight) to a height of 16 cm 20 times X d-1 (30 s between jumps) 5 d X wk-1 for 8 wk. Half of the exercised animals and half of the sedentary animals were injected with the anabolic steroid durabolin (0.2 mg in 0.1 ml sesame seed oil) 6 d X wk-1 for the last 3 wk of the 8-wk exercise program. The other animals were injected with 0.1 ml of sesame seed oil (as a placebo) on the same schedule. At the end of the 8-wk program, blood was drawn from the right atria of the anesthetized animals. Plasmas were analyzed for total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) concentrations. Low density lipoprotein cholesterol (LDL-C) concentration was estimated as the difference between these two parameters (TC - HDL-C). A three-factor analysis of variance (2 X 2 X 2) demonstrated that there was a significant (P less than 0.05) gender effect (males greater than females), but no steroid or exercise main effects for TC. There were significant (P less than 0.05) steroid and exercise main effects for both HDL-C and estimated LDL-C, as well as a significant gender main effect for estimated LDL-C (but not HDL-C).(ABSTRACT TRUNCATED AT 250 WORDS)