Search PubMed⌕ Search

Biomedical subjects

N Morris

Publications and source records attributed to N Morris.

At least 55 records · Page 3Linked to original sources
PubMed1991

Alternatively spliced type II procollagen mRNAs define distinct populations of cells during vertebral development: differential expression of the amino-propeptide.

Type II collagen is a major component of cartilage providing structural integrity to the tissue. Type II procollagen can be expressed in two forms by differential splicing of the primary gene transcript. The two mRNAs either include (type IIA) or exclude (type IIB) an exon (exon 2) encoding the major portion of the amino (NH2)-propeptide (Ryan, M. C., and L. J. Sandell. 1990. J. Biol. Chem. 265:10334-10339). The expression of the two procollagens was examined in order to establish a potential functional significance for the two type II procollagen mRNAs. First, to establish whether the two mRNAs are functional, we showed that both mRNAs can be translated and the proteins secreted into the extracellular environment. Both proteins were identified as type II procollagens. Secondly, to test the hypothesis that differential expression of type II procollagens may be a marker for a distinct population of cells, specific procollagen mRNAs were localized in tissue by in situ hybridization to oligonucleotides spanning the exon junctions. Embryonic vertebral column was chosen as a source of tissue undergoing rapid chondrogenesis, allowing the examination of a variety of cell types related to cartilage. In this issue, each procollagen mRNA had a distinct tissue distribution during chondrogenesis with type IIB expressed in chondrocytes and type IIA expressed in cells surrounding cartilage in prechondrocytes. The morphology of the cells expressing the two collagen types was distinct: the cells expressing type IIA are narrow, elongated, and "fibroblastic" in appearance while the cells expressing type IIB are large and round. The expression of type IIB appears to be correlated with abundant synthesis and accumulation of cartilagenous extracellular matrix. The expression of type IIB is spatially correlated with the high level expression of the cartilage proteoglycan, aggrecan, establishing type IIB procollagen and aggrecan as markers for the chondrocyte phenotype. Transcripts of type II collagen, primarily type IIA, are also expressed in embryonic spinal ganglion. While small amounts of type II collagen have been previously detected in noncartilagenous tissues, the detection of this new form of the collagen in relatively high abundance in embryonic nerve tissue is unique. Taken together, these findings imply a potential functional difference between type IIA and type IIB procollagens and indicate that the removal of exon 2 from the pre-mRNA, and consequently the NH2-propeptide from the collagen molecule, may be an important step in chondrogenesis. In addition, type II procollagen, specifically type IIA, may function in noncartilage tissues, particularly during development.

Animals↗
PubMed1991

Maternal serum alphafetoprotein screening. University Medical Center.

University Medical Center in Jacksonville initiated a screening program for maternal serum alphafetoprotein (MSAFP) in October 1987. Women with both high and low values were recalled for testing. During the first two years, neural tube and other birth defects including cystic hygroma and gastroschisis were detected. No chromosomal abnormalities were found. The program meets the recommendation of the American College of Obstetrics and Gynecology to offer MSAFP testing to all pregnant women. Pregnant women in other areas of Florida could receive services through similar programs.

Academic Medical Centers↗
PubMed1990

The management of predicted ovarian hyperstimulation involving gonadotropin-releasing hormone analog with elective cryopreservation of all pre-embryos.

Severe ovarian hyperstimulation syndrome complicates up to 6% of IVF treatment cycles. We have utilized our pre-embryo cryopreservation program to manage incipient ovarian hyperstimulation syndrome in an alternative way. Four women, who were at risk of developing ovarian hyperstimulation syndrome, underwent oocyte retrieval, but not embryo replacement. Instead, resulting pre-embryos were cryopreserved for future transfer. The four patients have since become pregnant. Three conceived after thawed embryo replacement cycles, and the fourth conceived spontaneously 1 month after the stimulation cycle. This approach offers maximum flexibility in the management of ovarian hyperstimulation syndrome.

Adult↗
PubMed1990

Habituation to irrelevant speech: effects on a visual short-term memory task.

The Baddeley and Hitch (1974) formulation of short-term or working memory embodied a phonological store within the articulatory loop component of the model. Later formulations specifically postulated an acoustic filter that endowed only speech-like stimuli with obligatory access to this phonological store. This paper presents evidence that this phonological store may have two filters, one of which is subject to habituation and can therefore attenuate the entry of irrelevant speech, thus undermining the obligatory access assumption of the model. An experiment is reported in which subjects were presented with a habituation period comprising 20 min of irrelevant speech--speech to be ignored by the subject--before a test phase in which a visually presented serial recall task with concurrent irrelevant speech was performed. The effect of irrelevant speech, which impairs performance on the primary task when there is no habituation phase, is reduced markedly in those conditions where the speech used in the habituation phase is the same as that used in the test phase, if the irrelevant speech is in a language different from that presented during the subsequent trials or if the habituator is a hummed version of the irrelevant speech passage. When a nonspeech sound (pink noise) is used in the habituation phase, a large irrelevant speech effect is found in the test phase. Morris, Quayle, and Jones (1989) found that humming did not produce an irrelevant speech effect, which suggests that the first filter is permeable to humming but that the second filter is not.(ABSTRACT TRUNCATED AT 250 WORDS)

Attention↗
PubMed1989

Spatial monitoring in visual working memory.

Three experiments examined the role of spatial monitoring in short-term visual memory. In the first experiment it was found that with consonants presented visually at one location articulatory suppression but not a concurrent tracking task disrupted performance. Experiment 2 demonstrated that tracking was disruptive when consonants were presented at three locations and more serial positions were affected when the locations of the consonants were random rather than highly predictable. Articulatory suppression was also disruptive in this study. The third experiment replicated the first two studies, without an articulatory suppression condition, using a within-subject design with a strictly forward serial recall constraint. The locus of the tracking effect was modified by this recall constraint suggesting that tracking disrupts a specific process that utilizes spatial monitoring. It was concluded that spatial monitoring depletes resources that can be used to encode visually presented consonants and these resources may be drawn from spatial working memory. The articulatory loop was also implicated given that articulatory suppression also disrupted performance. These results were explained in terms of working memory constellations. Morris (1986 b) suggested that such constellations consist of working memory components, in this instance the articulatory loop and spatial working memory, 'assembled' to meet task demands. This probably involves the activation, by the demand characteristics of the task, of modules in working memory that are similar to production system elements.

Adult↗
PubMed1988

Predictions of dangerousness: an argument for limited use.

Intense debate has focused on the use of statistical predictions of dangerousness in the criminal justice system. Two conflicting positions maintain wide support: that such predictions are never appropriate in criminal justice decision-making, and that they should be used far more often. Recognizing the fact that implicit and intuitive predictions are made every day in police, prosecutorial, sentencing, and other decisions, and explicit but unscientific predictions are common, this article suggests a theoretical framework justifying limited use of statistical predictions. Statistical predictions may present, in some instances, a morally preferable alternative to biased nonscientific and implicit judgements. Development of a sound jurisprudence of predictions faces major hurdles given the trend toward unscientific predictions in the law and the enormous judicial confusion in dealing with predictions. The concept has contributed to a string of notably poor Supreme Court decisions.

Criminal Law↗
PubMed1987

The psychology of briefing. A review and seven recommendations for improving performance.

In many operational settings, briefings take place at the beginning of a work period. Often, such briefings are made without much forethought and training. This article outlines some of the problems that are likely to be encountered in such situations and provides seven recommendations that should improve the memorability and comprehensibility of briefing sessions. It is recommended that briefings should begin with an outline of the critical points, be devoid of unnecessary detail and be confined to not more than six topics. Guidelines are provided for the use of pictures and graphs and combining these with verbal descriptions. The value of handouts and the use of summaries and prompts at the end of the briefing session are also considered.

Journal Article↗
PubMed1986

Birth centre confinement at the Queen Victoria Medical Centre: four years' experience.

A review of the first four years of the functioning of the birth centre at the Queen Victoria Medical Centre is presented. In that time, 1040 pregnant women were accepted for confinement there. Of these, 52 withdrew for non-obstetric reasons, while 470 were transferred to alternative obstetrical care--274 because of antepartum complications and 196 because of intrapartum problems. Therefore, 518 women were delivered in the birth centre. The care of the women is entrusted almost entirely to a team of midwives and this review demonstrates an enviable safety record.

Australia↗
PubMed1986

Partner support and the use of coping techniques in labour.

This study examined the relationship between partner support, use of pain control techniques and epidural anaesthesia in 80 primiparous women. It was found that the use of psychological 'pain control' techniques did not reduce the intensity of labour pain, nor did their use enable women to do without an epidural anaesthesic. However, the use of techniques did correlate with reduced frequency of anaesthesia when women were consistently supported and encouraged throughout labour, and when the labour was relatively short.

Adult↗