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Biomedical subjects

L Hall

Publications and source records attributed to L Hall.

At least 19 recordsLinked to original sources
PubMed2000

Molecular cloning and phylogenetic analysis of a cDNA encoding the cat (Felis domesticus) Ig epsilon constant region.

A feline splenic cDNA library was screened with a (32)P-labelled cDNA probe encoding the canine IgE epsilon heavy chain subunit. A cDNA sequence of 1614 nucleotides encoding the complete feline IgE heavy chain, as well as a portion of a variable region, was identified. A search of the GenBank database revealed an identity of 82% at the nucleotide level and 76% at the amino acid level between the feline epsilon heavy chain sequence and the canine homologue. In a separate study, feline genomic DNA, isolated from whole feline embryo cells, was subjected to PCR amplification using primers based on known partial genomic DNA sequences for the feline C epsilon gene. Following removal of an intron from the 683 bp PCR product, the coding sequence yielded an ORF of 506 bp. The DNA sequence of this PCR clone differed by a single nucleotide from the cDNA clone. This difference is silent, and therefore the proteins encoded by the two sequences are identical over the regions cloned and sequenced. Phylogenetic analysis of the constant regions of nine immunoglobulin epsilon genes revealed that the feline cDNA is most similar to the canine homologue.

Amino Acid Sequence↗
PubMed2000

Neutrino mass anarchy

What is the form of the neutrino mass matrix which governs the oscillations of the atmospheric and solar neutrinos? Features of the data have led to a dominant viewpoint where the mass matrix has an ordered, regulated pattern, perhaps dictated by a flavor symmetry. We challenge this viewpoint and demonstrate that the data are well accounted for by a neutrino mass matrix which appears to have random entries.

Journal Article↗
PubMed2000

Periovulatory human oocytes, cumulus cells, and ovarian leukocytes express type 1 but not type 2 11beta-hydroxysteroid dehydrogenase RNA.

OBJECTIVE: To further elucidate cortisol metabolism in the follicular microenvironment at the time of oocyte retrieval, the presence of 11beta-hydroxysteroid dehydrogenase (HSD) messenger (m)RNA transcripts in oocytes; cumulus cells; granulosa cells; and CD45(+), CD15(+) leukocytes was assessed semiquantitatively. DESIGN: Controlled study using semiquantitative assessment of 11beta-HSD mRNA. SETTING: University IVF center. PATIENT(S): Twenty-six patients undergoing controlled ovarian hyperstimulation for assisted conception. INTERVENTION(S): Metaphase II oocytes; cumulus cells; granulosa cells, and CD45(+), CD15(+) leukocytes from individual follicular fluid aspirates. MAIN OUTCOME MEASURES: Semiquantitative analysis of PCR products after total RNA extraction and complementary DNA synthesis. RESULT(S): Periovulatory human oocytes; cumulus cells; CD45(+), CD15(+) leukocytes; and granulosa cells consistently express type 1 but not type 2 11beta-HSD mRNA. Expression of mRNA is greatest in cumulus cells. Type 1 11beta-HSD mRNA expression varies considerably in all cell types and among individual follicles and patients. CONCLUSION(S): These studies of mRNA expression suggest that the enzymes present both in and around the periovulatory oocyte will favor a high-cortisol environment.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2000

Rat sperm 2B1 glycoprotein (PH20) contains a C-terminal sequence motif for attachment of a glycosyl phosphatidylinositol anchor. Effects of endoproteolytic cleavage on hyaluronidase activity.

Rat sperm 2B1 antigen (the orthologue of guinea pig sperm PH20) is a plasma membrane-bound glycoprotein that is endoproteolytically cleaved during passage through the epididymis and subsequently migrates from the tail to the acrosomal domain during capacitation. Unlike guinea pig PH20, however, sperm surface 2B1 is insensitive to phosphatidylinositol phospholipase C, nor is it known how endoproteolytic cleavage affects its hyaluronidase activity. In this investigation we have expressed 2B1 cDNA in Chinese hamster ovary cells; we have shown that it contains an internal sequence motif for attachment of a glycosyl phosphatidylinositol (GPI) anchor and that cleavage from a single- into a two-chain molecule causes a significant shift in the optimum pH for hyaluronidase activity. Functionally, these results suggest that 1) 2B1 glycoprotein on rat spermatozoa is attached to the plasma membrane via a GPI anchor and that this is an important factor in its ability to migrate from the tail to the acrosomal domain during capacitation; and 2) endoproteolytic cleavage of 2B1 serves to optimize its hyaluronidase activity immediately before fertilization, thereby facilitating penetration of spermatozoa through the cumulus oophorus.

Animals↗
PubMed2000

Quantitative approach to single-nucleotide polymorphism analysis using MALDI-TOF mass spectrometry.

Pooling of DNA samples before genotyping is a valuable means of streamlining large-scale genotyping efforts in disease association studies, single-nucleotide polymorphism (SNP) validation or mutant allele screening programs. In this report, we explore the application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to quantitative analysis of SNPs. The measurements are based on MALDI-TOF MS analysis of primer extension assays performed on standard mixtures of pooled PCR products at several test loci. The inherent high molecular weight resolution of MALDI-TOF MS conveys high specificity and good signal-to-noise ratio for performing accurate quantitation. The methods described maximize the sensitivity and quantitative capacity of MALDI-TOF MS while preserving the throughput and economic advantages of the MALDI-TOF platform. Using the format described, we demonstrate that allele frequencies as low as 5% can be detected quantitatively and unambiguously.

Alleles↗
PubMed2000

Expression of the cardiac actin gene in axolotl embryos.

Axolotis are an important model system for studying heart development. Patterning of the somitic mesoderm occurs in axolotis in a manner that is much more similar to the pattern observed in higher vertebrates than in Xenopus. For these reasons we cloned the axolotl cardiac actin gene, since this gene is expressed during the development of both somitic and cardiac muscle in other vertebrates. In this paper we characterize its expression. Expression of cardiac actin RNA is switched on during gastrula stages and appears in the somitic mesoderm when it is formed; expression is later activated in the embryonic heart. In adults the gene is expressed only in the heart. The results demonstrate that the clone encoding cardiac actin provides a useful marker for studying development of both skeletal and cardiac muscle development in axolotls.

Actins↗
PubMed1999

Transcripts encoding the sperm surface protein tMDC II are non-functional in the human.

Five members of the MDC (metalloproteinase-like,disintegrin-like cysteine-rich domain) family of proteins (fertilin alpha, fertilin beta, tMDC I, tMDC II and tMDC III) are expressed on the surface of macaque (Macaca fascicularis) sperm, where they have been proposed to play a role in sperm-egg binding via an interaction between their disintegrin-like domain and one or more integrins on the egg plasma membrane. Of these, two (fertilin alpha and tMDC I) have recently been shown to be non-functional in the human. Here we report the existence of multiple isoforms of human tMDC II transcripts in the human, all of which are also non-functional owing to the presence of deletions and in-frame termination codons, when compared with the macaque orthologue, a finding which is further supported by the lack of immunoreactivity on Western blots of human testis and sperm extracts probed with a macaque anti-tMDC II polyclonal antiserum. These results are discussed in the context of our proposed model for multiple proteins implicated in sperm-egg interactions.

ADAM Proteins↗
PubMed1999

Does cartilage down-regulate growth factor expression in tracheal epithelium?

BACKGROUND: Maintaining tracheal integrity and restoring normal physiologic function after injury is complex. Some of the critical events in this process are deposition of a provisional extracellular matrix, tissue remodeling, and angiogenesis. These events are coordinated with epithelial migration and proliferation to restore the mucosal barrier. The ability of respiratory epithelial cells (REC) to migrate and proliferate and restore denuded areas of the large conducting airway after injury is poor. OBJECTIVE: To test the hypotheses that (1) the cartilaginous framework, underlying the extracellular matrix (submucosa) and epithelium, decreases the migratory ability of REC when compared with REC on the same provisional extracellular matrix (type I collagen) alone, and (2) this phenomenon is associated with a change in expression of transforming growth factor (TGF)-alpha and TGF-beta, both of which have been demonstrated in cutaneous models to be important in epithelial migration and proliferation. DESIGN: We developed a culture system that reconstitutes the tracheal lumen in vitro, consisting of dissociated chondrocytes cultured in a manner to form cartilage, submucosa (type I collagen), and REC (termed a "composite culture"). Control cultures consisted of epithelial cells grown on type I collagen alone. Control and composite cultures were evaluated morphologically using scanning electron and light microscopy. Expression of TGF-alpha and TGF-beta was determined in day 14 cultured epithelial cells from control and composite cultures by semiquantitative polymerase chain reaction. RESULTS: Epithelial cells from composite cultures did not spread and were less squamoid in morphological appearance than epithelial cells on type I collagen alone. Expression of both growth factors was reduced in epithelial cells from composite cultures compared with those on type I collagen. CONCLUSIONS: Cartilage modulates TGF-alpha and TGF-beta expression in REC, and may contribute to regulation of REC proliferation and differentiation.

Animals↗
PubMed1999

Mammalian sperm-egg recognition: does fertilin beta have a major role to play?

The advent of simple in vitro fertilisation techniques has provided the reproductive biologist with an invaluable system for assaying sperm fertilising ability. In particular, they provide a useful way of identifying and characterising gamete-specific proteins that play a role in sperm-egg interactions, and in recent years, a growing number of sperm surface proteins have been identified that appear to be involved in these processes. Fertilin beta was one of the first sperm membrane proteins to be implicated in egg interactions and it has been proposed that this is mediated by means of binding of its disintegrin-like domain to cognate integrin receptors on the egg plasma membrane. A recent paper in Science by Cho and colleagues [Cho et al. 1998. Fertilisation defects in sperm from mice lacking fertilin beta. Science 281: 1857-1859 (Ref. 1)] provides preliminary data on a fertilin beta knockout mouse. Whilst fertilin beta null males had greatly reduced fertility, somewhat surprisingly, this could be largely attributed to causes other than impaired binding to the egg plasma membrane.

ADAM Proteins↗
PubMed1999

Localisation of phosphatidylethanolamine-binding protein in the brain and other tissues of the rat.

Phosphatidylethanolamine-binding protein (PEBP) is a highly-conserved 21- to 23-kDa basic protein that shows preferential affinity in vitro for phosphatidylethanolamine. Previous studies have focussed on PEBP in the brain and male reproductive tract where it has been proposed to play a role in membrane biogenesis. In the present more comprehensive study, rat PEBP transcripts and protein have been found to be expressed in all tissues examined, although the levels vary considerably between tissues. However, at the cellular level, PEBP expression is enigmatic, being restricted to a diverse range of highly specialised neuronal and non-neuronal cell types. The nature of this diversity, ranging from oligodendrocytes to plasma cells, whilst not precluding a role for PEBP in membrane biogenesis in some cell types, would imply that this is not the major function in others.

Adrenal Glands↗
PubMed1999

The potential use of sperm antigens as targets for immunocontraception; past, present and future.

Immunocontraception, and in particular the targeting of antibodies to gamete-specific antigens implicated in sperm egg binding and fertilisation, offers an attractive approach to the growing global problem of overpopulation. Such an idea is not new; indeed several immunocontraception trials, using animal model systems, have been reported in recent years and a number are reviewed here. However, the results of these studies have been largely disappointing. We believe that two fundamental flaws attribute to the poor success of most of these preliminary immunocontraceptive trials. Firstly, loss of fertility has invariably been used as the assay. This presupposes that immuno-neutralisation of a single, gamete-specific antigen will be sufficient to cause a significant reduction in fertility; however, recent data suggests that such a premise may not be well-founded for a number of reasons. Secondly, and arguably the most important flaw, is the almost universal, but largely inappropriate, use of systemic immunisation as the sole route of antigen delivery. Whilst systemic immunisation regimes may lead to high serum IgG levels, these levels do not correlate with specific antibody levels in the reproductive tract or with contraceptive efficacy. Hence, an alternative antigen delivery approach is required which will induce an effective local immune response in the reproductive tract. Here we discuss the ways in which this might be achieved.

Animals↗
PubMed1999

The results of adjustable suture technique in paediatric strabismus surgery.

PURPOSE: Adjustable suture technique (AST) has been shown to be an effective treatment method in adult strabismus. The application of AST is not well studied in children due to potential poor cooperation during adjustment and the concern that the adjustment process can not be completed. The present series evaluates the efficacy and safety of this technique in a preselected group of children between 7 and 15 years of age. METHODS: A retrospective review of 89 consecutive children undergoing AST was completed to assess: (1) the ability to perform and complete adjustment in children; (2) the frequency of need to perform adjustment; and (3) accuracy of surgical alignment. Only patients with horizontal rectus muscle surgery were included. RESULTS: All children successfully completed the AST on the first post-operative day. Of the 89 patients, 24 (27%) required further adjustment by the AST. The mean follow-up period was 13.1 months. Fifty-three patients (60%) had previous strabismus surgery (range 1 to 5 operations). Sixty-six (74%) patients achieved successful alignment. Complications included slipped muscles in 1 case and difficulty in recession of the lateral rectus muscle in 1 patient. CONCLUSIONS: Twenty-seven per cent of the patients required post-operative adjustment. The AST achieved an overall 74% successful alignment. Application of the AST should be considered in children with horizontal deviations over age 7 years, especially in the reoperations of esotropia.

Adolescent↗
PubMed1999

Autoradiographical and behavioural effects of a chronic infusion of antisense to the alpha2D-adrenoceptor in the rat.

1. The aims of this study were, firstly to use receptor autoradiography to investigate the effect of antisense oligonucleotides to the alpha2D-adrenoceptor on receptor binding and, secondly to measure behavioural and physiological parameters to determine whether the chronic antisense infusion had any effect on alpha2-adrenoceptor function in vivo. 2. A 3 day infusion of antisense to the alpha2D-adrenoceptor significantly reduced specific [3H]-RX821002 binding in the septum (20 - 30%) and anterior hypothalamic area (20 - 30%). beta-Adrenoceptor expression was unaffected in those brain areas examined, indicating the antisense knockdown was specific to the alpha2-adrenoceptors. 3. On the second day of the infusion, the hypothermic response to UK 14,304 was significantly attenuated in the antisense-treated group compared with both vehicle and mismatch controls. The effect was fully reversible and a similar decrease in body temperature was observed in all the treatment groups 4 days after the end of infusion. 4. During the second day of the infusion, the effects of UK 14,304 on behaviour were reduced in the antisense-treated rats, but were not significantly lower than those of the vehicle and mismatch, UK 14, 304 controls. These trends were not observed 4 days after the end of the infusion. 5. In conclusion, antisense has been shown to selectively knockdown alpha2-adrenoceptor expression in specific brain areas. The consequence of this knockdown is a significant attenuation of UK 14,304-induced hypothermia and a reduction in its sedative actions. These changes were fully reversed 4 days after the end of the infusion.

Animals↗
PubMed1999

Holmium:YAG laser lithotripsy of intrahepatic biliary calculi.

The holmium:YAG laser has been used effectively for a wide variety of urinary calculi. No cases have been reported of its in vivo use in the biliary system. In this report, we describe its utility in intracorporeal lithotripsy of intrahepatic biliary stones and the urologist's role in providing expertise in small-caliber endoscopy and lithotripsy to other disciplines.

Adult↗
PubMed1999

Identification, sequence analysis and expression of transcripts encoding a putative metalloproteinase, eMDC II, in human and macaque epididymis.

The metalloproteinase-like, disintegrin-like, cysteine-rich (MDC) family is a large group of sequence-related proteins, first characterized in the male reproductive tract, but subsequently also identified in non-reproductive tissues. Their primary translation products are of approximately 90 kDa and each can be divided into distinct domains which show remarkable homology to reprolysins; snake venom haemorrhagic components possessing metalloproteinase and/or disintegrin domains. Several MDC proteins are abundantly-expressed in the male reproductive tract, suggesting functions in fertility. We now describe the cloning, sequence determination and characterization of transcripts encoding the human and macaque (Macaca fascicularis) orthologues of a novel member of the MDC family (eMDC II) which is abundantly-expressed in the epididymis. Unlike many MDC proteins expressed in the reproductive tract, eMDC II possesses the extended 'catalytic centre' consensus sequence characteristic of a reprolysin-like metalloproteinase. This suggests that eMDC II has proteolytic activity.

ADAM Proteins↗
PubMed1999

The novel epididymal secretory protein ESP13.2 in Macaca fascicularis.

Newly synthesized mammalian spermatozoa undergo critical modifications as they pass along the epididymis. The modifications endow spermatozoa with fertilizing ability and occur largely as a consequence of epididymal gene expression. With this in mind, we here employed a cDNA cloning strategy designed to identify key epididymal gene products. We describe a novel cynomolgus monkey (Macaca fascicularis) epididymal transcript designated cy-ESP13.2, of 690 nucleotides. The putative human ortholog was cloned and is highly conserved. Both cDNA sequences predict small, secretory proteins with a disulfide-stabilized core. Anti-peptide polyclonal antibodies were raised to a predicted cy-ESP13.2 surface loop. Western blotting with these antibodies revealed high-level, epididymis-specific expression of cy-ESP13.2, consistent with the pattern of cy-ESP13.2 mRNA expression assessed by Northern blotting. cy-ESP13.2 protein was of 30 kDa and was readily detectable in epithelial cells lining the efferent ductules, initial segment, and cauda regions of the epididymis, but not on spermatozoa. Similarities to members of the four-disulfide-core family suggest clues to ESP13.2 function.

Amino Acid Sequence↗
PubMed1999

The therapeutic use of music for dyspnea and anxiety in patients with COPD who live at home.

The purposes of this repeated measures study were to examine the feasibility of using music as an intervention for dyspnea and anxiety in patients with chronic obstructive pulmonary disease (COPD) who live in their homes and to examine the effect of music on anxiety and dyspnea. Twenty-four participants who experienced dyspnea at least once a week were studied over a 5-week period. Baseline data were collected on Week 1. Measures of anxiety and dyspnea were taken on Week 2, prior to and immediately following the use of music. These measures were repeated on Week 5. There was a significant decrease in dyspnea following the use of music as reported in the music diary (p < .001). There was a significant decline in anxiety (p < .05) and dyspnea (p < .01) following the use of music on Week 2. There was no significant change in anxiety or dyspnea over the 5-week period.

Aged↗