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Biomedical subjects

J Light

Publications and source records attributed to J Light.

At least 37 records · Page 2Linked to original sources

Sensory/motor therapy for the treatment of oral dyskinesia. A new approach to the treatment of oromyofunctional disorders with the use of tactile cuing handheld exercisers.

Persons with oral myofunctional disorders suffer from multiple risk factors for impairments. A craniofacial malformation may be responsible for both behavioral as well as structural modifications. This includes the effect of appearance on self concept and behavior (Case, 1988). Structural modifications as well as negative oral habits include: an open mouth resting posture; mouth breathing; low forward tongue carriage; forward articulatory tongue placement (linguadental/lingua alveolar); abnormal lip, tongue and facial muscle movements during swallowing; reduced upper lip length and mobility; overcontraction of the mentalis muscle; negative habits such as nailbiting, thumb or finger-sucking, lip biting, and lip licking (Hale and Kellum, 1988). Clinical observations also include hypotonicity of the posterior oral musculature during swallowing activity. The purpose of this article is to explore the etiology of oral myofunctional disorders and present a new approach to treatment using functional prosthetic therapy.

Adult↗

Loss of quality adjusted days as a trial endpoint: effect of early thrombolytic treatment in suspected myocardial infarction. Grampion Region Early Anistreplase Trial (GREAT).

STUDY OBJECTIVES: (1) To measure the quality of life and the loss of quality adjusted days (QADS) after suspected acute myocardial infarction in patients who received thrombolytic treatment either at home or in hospital. (2) To compare the loss of QADS as a trial endpoint with the conventional endpoints of mortality and Q-wave infarction. DESIGN: Randomised double blind parallel group trial of anistreplase (30 U given intravenously) and placebo given either at home or in hospital. SETTING: Rural practices in Grampian admitting patients to teaching hospitals in Aberdeen. PATIENTS: A total of 311 patients with suspected acute myocardial infarction and no contraindications to thrombolytic treatment seen at home within four hours of the onset of symptoms. MEASUREMENTS AND MAIN RESULTS: Loss of quality adjusted days (QADS) in the first 100 days after suspected myocardial infarction (365 QADS = 1 QALY) was the main outcome measure. Compared with later administration in hospital, anistreplase at home resulted in a relative reduction of mortality of 49% (95% confidence interval 3.95%, 2p = 0.04), and a relative reduction of 26% in the proportion of survivors with infarction who had Q-waves (95% CI 7.44%, 2p = 0.007). During the 100 day follow up, the median loss of QADS was 25 for all patients. This loss was significantly greater in those who died than in survivors (65 v 18, 2p < 0.001), and in survivors with infarction than in survivors without infarction (26 v 13, 2p < 0.01). However, there was no significant difference in loss of QADS in those with infarction with or without Q-waves (29 v 21, NS), and the median loss of QADS was not significantly different in those who had thrombolytic treatment at home or in hospital (median difference 0, 95% CI -5, +4 QADS). CONCLUSIONS: Loss of QADS had two serious limitations as an outcome measure: it was less sensitive than mortality and it failed to reflect physiological benefit. Palliative treatment with no physiological effect would have resulted in a greater gain in QADS (or QALYs) than did early thrombolytic treatment. Extreme caution is required in accepting a gain in QALYs as a valid outcome measure for health care.

Anistreplase↗

Message-encoding techniques for augmentative communication systems: the recall performances of adults with severe speech impairments.

This study investigated the cognitive and linguistic processing demands of message-encoding techniques used to retrieve prestored messages from computer-based augmentative communication systems. Twelve physically disabled adults with severe speech impairments participated in six counterbalanced experimental conditions, consisting of three encoding techniques (salient letter, letter category, and iconic codes), each in a personalized condition in which subjects selected their own codes and in a nonpersonalized condition in which codes were preselected by a clinician. In each of the experimental conditions, the subjects participated in five learning and testing sessions. During these sessions, the subjects learned the codes for lists of 80 messages, half of which involved concrete referents and half abstract concepts. Results indicated that the subjects were more accurate in recalling the codes to retrieve preprogrammed messages when using the two letter encoding techniques than when using the iconic technique. No reliable differences were found between recall performances with personalized codes and with nonpersonalized ones for any of the three encoding techniques. Code recall improved consistently across the series of learning sessions; there were no significant differences in the rates of learning across the encoding techniques. Subjects were found to be more accurate at recalling the codes to retrieve concrete messages than those to retrieve abstract messages.

Adult↗

Instructing facilitators to support the communication of people who use augmentative communication systems.

A single-subject multiple-baseline design, replicated across three dyads, was used to examine the efficacy of instructing facilitators (i.e, significant others) to promote communication with people who use augmentative and alternative communication (AAC) systems. Facilitators were instructed in four 1-hour sessions to decrease their conversational control and provide more opportunities for the participants using AAC systems to communicate. Following instruction, facilitators decreased their rates of turn-taking and initiations and increased the proportion of turns that were responsive. Participants using AAC systems increased the frequency of their initiations. Following intervention, turn-taking and initiation patterns in the dyads were more reciprocal. Generalization occurred to the natural environment. Results suggest that facilitator instruction is an effective and efficient means of promoting greater participation in daily interactions by people who use AAC systems.

Adolescent↗

Quality of life in the first 100 days after suspected acute myocardial infarction--a suitable trial endpoint?

STUDY OBJECTIVE: The aim was to determine the loss of quality of life following admission to hospital with suspected myocardial infarction. DESIGN: The study involved a cohort of admissions, with interview and follow up for 100 days. Main outcome measures were the quality of life prior to admission and at each stage of convalescence, estimated using the Rosser-Kind matrix: the calculated number of quality adjusted days during a 100 d follow up period. SETTING: The study took place in a teaching hospital in Scotland. PATIENTS: 206 patients were admitted with suspected acute myocardial infarction. Infarction was confirmed in 160 (Q wave infarcts 100, non-Q-wave infarcts 60), and unconfirmed in 46. MAIN RESULTS: The quality of life scores before the suspected heart attack were similar for patients whose final diagnosis was Q wave infarction, non-Q-wave infarction, or non-infarction. Of the 160 patients with confirmed infarction, only 54 (34%) had regained their previous quality of life scores at the end of 100 days, compared with 26 of 46 (57%) patients with unconfirmed infarction (p < 0.01). The mean numbers of quality adjusted days lost to patients with Q wave infarction, non-Q-wave infarction, and non-infarction were 17.0, 12.4, and 5.9 respectively (infarction v non-infarction, p < 0.0001). Measurements of both quantity and quality of life contributed to these results. CONCLUSIONS: The number of quality adjusted days lost after acute myocardial infarction is a practicable measurement that is relevant to patients' lives. It might be suitable as an outcome measure for clinical trials of thrombolytic therapy.

Adult↗

Plasmodium falciparum: ingested anti-sporozoite antibodies affect sporogony in Anopheles stephensi mosquitoes.

In endemic areas, malaria-infected mosquitoes may feed upon humans who possess antibodies against malaria sporozoites. Therefore, we examined the effect that ingested anti-sporozoite antibodies have upon Plasmodium falciparum sporogony within Anopheles stephensi mosquitoes. Anti-sporozoite antibodies (IgG) traversed the midgut into the hemocoel within 3 hr following ingestion and, depending upon the titer, persisted for 6-24 hr. When fed to infected A. stephensi at 12 days postinfection (p.i.), anti-sporozoite antibodies bound to sporozoites in the hemocoel, but not to sporozoites residing in the salivary glands of the same mosquitoes. Anti-sporozoite antibodies also bound to developing oocysts when fed to infected A. stephensi at 5 days p.i. Oocysts in mosquitoes that had been fed anti-sporozoite antibodies on Day 5 p.i. produced significantly more sporozoites than did oocysts in nonimmune-fed (Day 5 p.i.) mosquitoes. In addition, the sporozoites from Day 5 immune-fed mosquitoes were significantly more infective to cultured human hepatoma cells than were sporozoites from nonimmune-fed controls. Use of hetereologous immune feedings at Day 5 p.i. did not result in an enhanced production of sporozoites, suggesting that enhancement is related to the specificity of the antibody and is not merely a nutritional effect.

Animals↗

Identification and characterization of mutations responsible for a runaway replication phenotype of plasmid R1.

Initiation of replication of the resistance plasmid R1 is carefully regulated by the two negatively acting factors, CopA and CopB. It is shown here that the temperature-dependent runaway-replication phenotype of an R1 plasmid mutant is caused by two point mutations in each of the promoters for the genes of these control factors. Expression of the two genes is affected in the following way: (1) one C-to-T transition in the putative -35 box of the copB-repA operon creates a two- to three-fold stronger promoter from which expression is temperature-dependent; (2) another C-to-T transition in a G + C-rich area immediately downstream from the -10 box of the copA promoter reduces expression of the copA gene three-fold. The phenotypic consequences of the two mutations are discussed in the light of the current model for R1 replication control.

Base Sequence↗

"Unclassifiable" weak A blood group and deficient H phenotype (Hm) in one pedigree. Variants of A and H types in a family.

A new variant of blood group A [A(WAS)] was expressed in three generations of a Caucasian family: Phenotype included weak mixed field hemagglutination by anti-A reagents, secretion of H substance, and presence of anti-A1 in serum. The A(WAS) variant was inherited in a Mendelian fashion, dominant to O. A-transferase activity was absent from cells and saliva but was 0.2% of normal A1 transferase activity in serum, with a pH optimum of 6.0. Family members expressing A(WAS) also demonstrated partly deficient H type on cells (Hm). H-transferase activity in serum was normal for a weak A subgroup and showed typical Km and acceptor specificities. Linkage of H-modifier and ABO loci cannot be excluded.

ABO Blood-Group System↗

Transcription and its regulation in the basic replicon region of plasmid R1.

The transcriptional units in the basic replicon of plasmid R1 were defined by means of gene fusions. It was found that in the wild-type plasmid there is one large mRNA encoding both the control factor copB and the positive replication factor repA. A second, internal transcription initiation site, the repA promoter, is usually repressed by the copB protein, and is therefore only of significance in the absence of this control factor. By induction of the repA promoter through gradual dilution of the copB repressor it was shown that translation of repA-mRNA, controlled by the copA-RNA, is significantly increased only when the rate of repA transcription is above a certain level. No indication was found for a possible interference from convergent copA transcription on repA transcription.

Base Sequence↗

Expression in Bacillus subtilis of the gene for human urogastrone using synthetic ribosome binding sites.

A chemically synthesised gene coding for human urogastrone which was earlier cloned in E. coli (Smith et al. 1982) has now been cloned into expression vectors for Bacillus subtilis. Two types of constructs have been made, one giving production of methionyl-urogastrone and the other giving rise to a methionyl-urogastrone-beta galactosidase fusion polypeptide facilitating quantification of expression levels. The ribosome binding sites used in the expression plasmids are synthetically made oligonucleotides residing on short restriction fragments to allow easy replacement by other ribosome binding sites. Using "shuttle" vectors and constitutive promoters from Bacillus phages phi 105 and SPP1, we were able to detect levels of expression amounting to a few thousand molecules per cell during logarithmic growth in both E. coli and B. subtilis.

Amino Acid Sequence↗

Control of replication of bacterial plasmids: genetics, molecular biology, and physiology of the plasmid R1 system.

Plasmids are autonomously replicating DNA molecules that are present in defined copy numbers in bacteria. This number may for some plasmids be very low (2-5 per average cell). In order to be stably inherited, replication and partitioning of the plasmid have to be strictly controlled. Plasmids carry genetic information for both processes. In the present paper we summarize what is known about the replication control system of one low-copy-number plasmid, R1, belonging to the FII incompatibility group. We do so because the FII group seems to be one of the best understood examples with respect to genetics, molecular biology, and physiology of the replication control system. The paper is not a classical review, but rather an essay in which we discuss the aspects of replication control that we regard as being important.

Bacterial Proteins↗

Low-copy-number plasmid-cloning vectors amplifiable by derepression of an inserted foreign promoter.

By insertion of a DNA fragment, containing the phage lambda pR promoter and the pM-promoted cI857 allele of the lambda repressor gene, in plasmid R1 upstream of the replication control genes, cloning vectors have been constructed which are present in one copy per chromosome at temperatures below 37 degrees C, and which display uncontrolled replication at 42 degrees C. Derivatives have been made which carry the R1 par region, stabilizing the plasmid at low temperature when grown in the absence of selection pressure. Cells harbouring these plasmids stop growing after 1-2 h incubation at 42 degrees C, and at this time 50% of the total DNA in the cells is plasmid DNA corresponding to more than 1000 plasmid molecules per cell. Concomitant with plasmid amplification at the high temperature, synthesis of plasmid-coded gene products is amplified, and these vectors can therefore be utilized for obtaining greatly enhanced yields of gene products that may be detrimental to the host cell when present in large amounts.

DNA Replication↗

Post-transcriptional control of expression of the repA gene of plasmid R1 mediated by a small RNA molecule.

Fusions between the repA gene of plasmid R1 (required for autonomous plasmid replication) and the lac genes have been the basis for in vivo studies of regulation of repA expression. Two gene products--the CopA RNA and the CopB protein--act as inhibitors of repA expression. Comparison of the effects of addition in trans of the two Cop functions on transcription and translation of repA-lac gene fusions show that the CopB protein represses transcription of the repA gene, whereas the CopA RNA interferes with the RepA mRNA in such a way that effective translation is inhibited. The CopA RNA does not seem to have a direct effect on the transcription of the repA gene but, as a consequence of the posttranscriptional regulation, transcriptional polarity within the repA gene is observed. It is also shown that the CopA RNA interacts with its target (CopT) only when the region is transcribed to form RepA mRNA.

Artificial Gene Fusion↗