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Biomedical subjects

L McAllister

Publications and source records attributed to L McAllister.

18 recordsLinked to original sources
PubMed2001

Bacillus circulans endophthalmitis.

An 80-year-old woman presented with right endophthalmitis, characterized by chalky white deposits covering her posterior capsule. This occurred 17 months after uncomplicated right cataract surgery. A three-port pars plana vitrectomy and partial posterior capsulectomy isolated Bacillus circulans, and the patient made a rapid and full recovery on topical cephalothin and prednisolone acetate 1%. The case demonstrates that, unlike endophthalmitis due to other Bacillus spp., B. circulans endophthalmitis does not necessarily follow a fulminant course. It is the first report describing a subacute presentation, and response to posterior capsulectomy and simple antibiotic therapy It is also the first description of B. circulans causing white plaques in the posterior capsule, a finding characteristic of chronic endophthalmitis and previously considered pathognomonic of Proprionibacterium acnes endophthalmitis.

Aged↗
PubMed1998

Enrichment for loci identical-by-descent between pairs of mouse or human genomes by genomic mismatch scanning.

Mapping genes that underlie complex genetic traits, including genes that determine susceptibility to common diseases, requires an efficient method for high-resolution genotyping. Single-nucleotide differences between pairs of allelic sequences from unrelated individuals occur approximately once in every kilobase. Genomic mismatch scanning (GMS), by analyzing numerous single-nucleotide polymorphisms in a single genome-wide step, offers a potentially powerful and efficient approach to linkage analysis. GMS, originally developed in a yeast system, is shown here to be applicable to the more complex mouse and human genomes.

Adenosine Triphosphatases↗
PubMed1998

Rural attachments for students in the health professions: are they worthwhile?

In the period 1991-96, 156 undergraduates from 14 health disciplines at the University of Sydney completed rural attachments in rural and remote areas of Australia as part of the Rural Careers Project. On return from their attachment, students were encouraged to write a brief report of their experiences. Ninety-two available reports were analysed as one means of assessing the success of the attachments with respect to informing students about rural health issues and stimulating their interest in rural careers after graduation. A content analysis of the students' written comments about their perceptions and experiences was completed. Students were extremely positive about the value of the attachments and expressed more positive than negative comments regarding their perceptions of rural life and work. The results show that rural attachments are indeed worthwhile learning opportunities.

Allied Health Personnel↗
PubMed1993

Speech and language outcomes 3 years after neonatal intensive care.

Although major handicap rates have been documented in children who required neonatal intensive care, minor handicap rates, including speech and language problems, have received less attention. This paper reports the first stage of a longitudinal study of 118 children, which investigated the speech and language outcomes at 3 years of age. Differences from the normal population were found for the articulation measure, but not for the language comprehension and expression measures used. A major overall communication problem was determined to exist in 13% of the children. The impact of perinatal, medical and environmental variables was investigated. Variables such as low birthweight, short gestational age and mechanical ventilation, found to be important in other studies, had no significant impact on the speech and language outcomes of this cohort of 3 years old. However, for children who had experienced respiratory distress syndrome, there was an effect on articulation and language expression. Paediatric complications and maternal education level had the largest effects on language comprehension and expression, suggesting they were the persistent variables which most contributed to speech and language outcomes at 3 years of age.

Articulation Disorders↗
PubMed1993

Speech and language outcomes in preschool-aged survivors of neonatal intensive care.

This paper reports on the second stage of a longitudinal follow-up of the speech and language outcomes in a cohort of children who required neonatal intensive care. From 3 years of age, when the first stage was completed, to preschool age, the rate for major overall communication problems rose from 13% to 17%. However, when children with frank neurological or intellectual problems were excluded, this figure dropped to 8%. The impact of perinatal, medical and environmental variables on speech and language outcomes was again investigated. Differences were found between those that were important at 3 years of age and those that were important at preschool age. New variables emerged as contributing to language expression, including gender and the perinatal variables, gestational age and respiratory distress syndrome. Maternal education level was even more important to language comprehension at preschool age than at 3 years of age. Factors that might explain improvement, or lack of improvement, in speech and language skills are discussed.

Child, Preschool↗
PubMed1992

Dynamic expression of the cell adhesion molecule fasciclin I during embryonic development in Drosophila.

A number of different cell surface glycoproteins expressed in the central nervous system (CNS) have been identified in insects and shown to mediate cell adhesion in tissue culture systems. The fasciclin I protein is expressed on a subset of CNS axon pathways in both grasshopper and Drosophila. It consists of four homologous 150-amino acid domains which are unrelated to other sequences in the current databases, and is tethered to the cell surface by a glycosyl-phosphatidylinositol linkage. In this paper we examine in detail the expression of fasciclin I mRNA and protein during Drosophila embryonic development. We find that fasciclin I is expressed in several distinct patterns at different stages of development. In blastoderm embryos it is briefly localized in a graded pattern. During the germ band extended period its expression evolves through two distinct phases. Fasciclin I mRNA and protein are initially localized in a 14-stripe pattern which corresponds to segmentally repeated patches of neuroepithelial cells and neuroblasts. Expression then becomes confined to CNS and peripheral sensory (PNS) neurons. Fasciclin I is expressed on all PNS neurons, and this expression is stably maintained for several hours. In the CNS, fasciclin I is initially expressed on all commissural axons, but then becomes restricted to specific axon bundles. The early commissural expression pattern is not observed in grasshopper embryos, but the later bundle-specific pattern is very similar to that seen in grasshopper. The existence of an initial phase of expression on all commissural bundles helps to explain the loss-of-commissures phenotype of embryos lacking expression of both fasciclin I and of the D-abl tyrosine kinase. Fasciclin I is also expressed in several nonneural tissues in the embryo.

Animals↗
PubMed1992

Alternative splicing of micro-exons creates multiple forms of the insect cell adhesion molecule fasciclin I.

Fasciclin I is a homophilic cell adhesion molecule in insects that is dynamically expressed on a subset of axon pathways in the embryonic nervous system, and on a variety of other cells and tissues during development. The fasciclin I protein consists of four homologous 150 amino acid domains. In this article, we describe the complete sequence of the Drosophila fasciclin I (fasI) gene. The gene consists of 15 exons and is distributed over 14 kilobases of DNA. We examine the structure and temporal expression pattern of multiple fasciclin I mRNAs that differ in the lengths of their 3' untranslated regions. We also show that a highly conserved sequence at the end of the second domain can be altered by the addition of three or six amino acids that are encoded by two alternatively spliced 9 base pair (bp) micro-exons. In grasshopper fasciclin I mRNAs, there are 9 bp and 6 bp insertions at the same position. The first of these insertions is identical in sequence to the first fly micro-exon. The grasshopper insertions are not found together in the same mRNA, so grasshopper fasciclin I species differ by the addition of three or two extra amino acids to the second domain. The alternatively spliced mRNAs are differentially expressed during embryogenesis, and all three of them are present in nerve cord preparations. We suggest that the amino acids inserted by alternative micro-exon splicing may alter the binding specificity of fasciclin I.

Animals↗
PubMed1990

Genetic analysis of a Drosophila neural cell adhesion molecule: interaction of fasciclin I and Abelson tyrosine kinase mutations.

Drosophila fasciclin I is a homophilic cell adhesion molecule expressed in the developing embryo on the surface of a subset of fasciculating CNS axons, all PNS axons, and some nonneuronal cells. We have identified protein-null mutations in the fasciclin I (fas I) gene, and show that these mutants are viable and do not display gross defects in nervous system morphogenesis. The Drosophila Abelson (abl) proto-oncogene homolog encodes a cytoplasmic tyrosine kinase that is expressed during embryogenesis primarily in developing CNS axons; abl mutants show no gross defects in CNS morphogenesis. However, embryos doubly mutant for fas I and abl display major defects in CNS axon pathways, particularly in the commissural tracts where expression of these two proteins normally overlaps. The double mutant shows a clear defect in growth cone guidance; for example, the RP1 growth cone (normally fas I positive) does not follow its normal path across the commissure.

Alleles↗
PubMed1988

Sequence analysis and neuronal expression of fasciclin I in grasshopper and Drosophila.

The fasciclin I, II, and III glycoproteins are expressed on different subsets of axon bundles (fascicles) in insect embryos and are thus candidates for surface recognition molecules involved in growth cone guidance. Here we present the sequence of grasshopper fasciclin I and the identification and sequence of the Drosophila fasciclin I homolog. In both species, fasciclin I appears to be an extrinsic membrane protein with a signal sequence but no transmembrane region; the protein comprises four homologous domains of approximately 150 amino acids each. Antibodies against Drosophila fasciclin I reveal that it is expressed on the surface of a subset of commissural axon pathways in the embryonic central nervous system and on all sensory axon pathways in the peripheral nervous system. This pattern of expression is similar to that in grasshopper.

Amino Acid Sequence↗
PubMed1988

Characterization and cloning of fasciclin I and fasciclin II glycoproteins in the grasshopper.

Monoclonal antibodies were previously used to identify two glycoproteins, called fasciclin I and II (70 and 95 kDa, respectively), which are expressed on different subsets of axon fascicles in the grasshopper (Schistocerca americana) embryo. Here the monoclonal antibodies were used to purify these two membrane-associated glycoproteins for further characterization. Fasciclin II appears to be an integral membrane protein, whereas fasciclin I is an extrinsic membrane protein. The amino acid sequences of the amino terminus and fragments of both proteins were determined. Using synthetic oligonucleotide probes and antibody screening, we isolated genomic and cDNA clones. Partial DNA sequences of these clones indicate that they encode fasciclins I and II.

Amino Acid Sequence↗
PubMed1986

Physiology of the peaked finger pulse in normal and cold-sensitive subjects.

A unique peaked digital pulse contour (DPC) is frequently observed in patients with cold sensitivity, but the pathophysiology of this pulse remains obscure. To investigate the responses of the DPC to cold exposure, finger blood pressure (FBP), finger blood flow (FBF), and finger skin temperature (FST) were measured in fingers of both hands of 13 normal subjects and in 16 patients with cold sensitivity. The ratio, FBP/FBF, was used to estimate small vessel resistance (SVR). One hand was immersed sequentially in water at 40 degrees, 30 degrees, 20 degrees, and 10 degrees C, while the other hand remained in room air. DPCs were classified as normal (N), intermediate (I), intermediate-peaked (IP), peaked (P), obstructive (O), and spastic obstructive (SO). At room temperature, fingers with I, IP, O, and SO pulses had increased SVRs and decreased FSTs, and those with O and SO had decreased FBP. On cold exposure IP pulses appeared in both hands of both normal and cold-sensitive subjects, but P pulses developed only on the cooled side. IP and P pulses were associated with an increase in SVR. We concluded that IP pulses are related to reflex sympathetic arteriolar vasoconstriction, that P pulses imply vasoconstriction produced directly by cold exposure, and that O, SO, or absent pulses are indicative of digital arterial vasospasm.

Adolescent↗
PubMed1981

Liposome-cell interactions. A study of the interactions of liposomes containing entrapped anti-cancer drugs with the EMT6, S49 and AE1 (transport-deficient) cell lines.

A study has been made to determine if the cytotoxicity observed when cells in culture were exposed to liposome-entrapped cytotoxic drugs was liposome mediated or resulted from leakage of drug from the liposomes with subsequent uptake of free drugs by the cells. In preliminary experiments with the EMT6 cell line in monolayer culture, the cytotoxicity observed when the cells were exposed to a range of concentrations of liposome-entrapped methotrexate, actinomycin D and cytosine arabinoside for a variety of liposome compositions was somewhat less than that observed when the cells were exposed to similar concentrations of free drug. We suspected that the cytotoxicity was mediated via uptake of free drug leaked from liposomes. This was confirmed in experiments involving the EMT6 and S49 cell lines in monolayer or suspension culture, respectively, in the absence and presence of the nucleoside transport inhibitor, 6-(4-nitrobenzyl)thio)-9-beta-D-ribofuranosylpurine. Additional experiments were performed in a transport-deficient mutant of the S49 cell line, the AE1 cell line. No evidence for liposome-mediated cell death could be found in these cell lines when tubercidin 5'-monophosphate was entrapped in either large or small unilamellar liposomes composed of egg phosphatidylcholine/cholesterol (2 : 1), bovine brain phosphatidylserine/egg phosphatidylcholine/cholesterol (8 : 2 : 5) or egg phosphatidylcholine/stearylamine/cholesterol (10 : 1 : 5). Considerable toxicity due to empty liposomes of a variety of compositions was observed in the S49 cell line at high lipid concentrations.

Animals↗
PubMedDate not supplied

Effects of cutaneous aspirin on the human stomach and duodenum.

Oral aspirin blocks cyclooxygenase in platelets, lowering serum thromboxane concentrations. Oral aspirin also blocks cyclooxygenase in the gastrointestinal mucosa, lowering prostaglandin production and increasing the risk of gastrointestinal ulceration and bleeding. Aspirin placed on the skin also inhibits cyclooxygenase in platelets, but aspirin absorption through skin is slow, which may minimize the gastrointestinal effects. Our objectives in this study were 1) to compare the pharmacokinetic and pharmacodynamic effects of cutaneous and oral aspirin in healthy volunteers and 2) to compare the effects of cutaneous aspirin on gastroduodenal mucosal prostaglandin E2 and F2 alpha content and on mucosal damage, using endoscopy. The bioavailability of cutaneous aspirin was 4%-8% that of oral aspirin. Cutaneous aspirin (750 mg/day for 10 days) significantly lowered serum thromboxane (by 85%) and gastric and duodenal prostaglandins (by 49%-71%); placebo had no effect. Moreover, cutaneous aspirin, but not placebo, resulted in significant gastric mucosal injury. These findings demonstrate that even tiny amounts of aspirin in the blood (2 microM) have inhibitory effects on prostaglandin production in the human stomach and duodenum that result in gastric mucosal damage, even without direct exposure of the stomach to aspirin.

Administration, Cutaneous↗
PubMedDate not supplied

Public opinion on tobacco use, its taxes and public policy.

Public opinion is an important vehicle in shaping legislative efforts and public policy related to tobacco use and related taxes. This study examined public opinion about policy related to tobacco use and raising tobacco taxes in a Midwestern state. The American Lung Association of Indiana provided a grant to sponsor this project. A structured questionnaire was developed, field tested and revised for the final data collection procedure. A sample of 800 adult subjects was randomly selected and telephone interviewed by the Indiana University Center for Survey Research. The collected data were subjected to descriptive and inferential statistics. The data revealed a good representative sample of adult males and females for various age groups and socioeconomic backgrounds. Among other findings, 29% were currently smokers, 23% were former smokers, and 47.5% never smoked. More than 90% support a requirement that public places have nonsmoking areas. About 85% favor an increase in cigarette taxes to pay for health education and tobacco-related research. The relationship of the subjects' gender, education and income to their opinion about the various aspects of tobacco, taxes and related policies were examined.

Adult↗