Biomedical subjects

L Hall

Publications and source records attributed to L Hall.

At least 37 records · Page 2Linked to original sources

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↗

PubMed1999

Medication compliance.

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Acquired Immunodeficiency Syndrome↗

PubMed1998

Fatty acids stimulate cholecystokinin secretion via an acyl chain length-specific, Ca2+-dependent mechanism in the enteroendocrine cell line STC-1.

1. The present study has investigated whether fatty acids directly influence peptide release from enteroendocrine cells using STC-1, a mouse intestinal endocrine tumour cell line, previously shown to release cholecystokinin (CCK) in response to other physiological stimuli. 2. Fatty acids elicited a chain length- and dose-dependent stimulation of CCK secretion. Dodecanoic acid (C12) was most effective, producing up to a 5-fold increase in CCK secretion. Fatty acids with less than ten carbon atoms did not increase secretion. The chain length dependence of these effects mimics closely fatty acid-induced CCK secretion previously observed in humans in vivo. 3. Esterification of C12 abolished CCK secretion, indicating a critical role for a free carboxyl group in eliciting secretion. In contrast, modification of the methyl terminus had no effect on C12-induced secretion. The non-metabolizable C12 analogue 2-bromododecanoic acid was equally effective. 4. C12 elicited a marked increase in intracellular calcium levels (200-300 nM) in STC-1 cells which was abolished by the L-type Ca2+ channel antagonist nicardipine. In contrast, C8 produced a smaller and more transient Ca2+ response. C12-induced CCK secretion was also blocked by nicardipine. 5. These data suggest that fatty acids can interact directly with enteroendocrine cells to stimulate CCK secretion via increases in intracellular calcium mediated primarily by L-type Ca2+ channels.

Animals↗

PubMed1998

The gene for the human tMDC I sperm surface protein is non-functional: implications for its proposed role in mammalian sperm-egg recognition.

The sperm surface antigen tMDC I (also known as cyritestin) has been proposed to play a role in sperm-egg binding in the mouse via an interaction between its disintegrin-like domain and an integrin receptor on the oolemma plasma membrane. Here we report the cloning and sequence of human tMDC I transcripts and show that they are non-functional, owing to the presence of a variety of deletions, insertions and in-frame termination codons. The absence of a tMDC I protein is further supported by the lack of immunoreactivity on Western blots of human testis and sperm extracts probed with macaque (Macaca fascicularis) and human anti-tMDC I antisera.

ADAM Proteins↗

PubMed1998

The majority of human glutathione peroxidase type 5 (GPX5) transcripts are incorrectly spliced: implications for the role of GPX5 in the male reproductive tract.

An epididymis-specific, secretory glutathione peroxidase (GPX5) has been proposed previously to play a role in protecting mammalian sperm membranes from the deleterious effects of lipid peroxidation, which, if not contained, can lead to reduced fertilizing capacity. Here we report the cDNA cloning of human GPX5 and show that the majority of transcripts contain a 118 nt frame-shifting deletion, arising, most likely, from inappropriate excision of exon 3 during processing. Antisera raised against recombinant human GPX5 cross-reacted with rat and macaque (Macaca fascicularis) epididymal proteins of the size expected for full-length, active GPX5. However, no similar reactivity could be demonstrated in any of the human samples tested.

ATP-Binding Cassette Transporters↗

PubMed1998

Isolation and characterization of alpha-tubulin genes from Septoria tritici and Rhynchosporium secalis, and comparative analysis of fungal alpha-tubulin sequences.

The alpha-tubulin genes from Septoria tritici and Rhynchosporium secalis have been cloned and sequenced. The predicted amino acid sequence and intron structure showed strong homology with other known filamentous fungal alpha-tubulins. Comparison of sixteen fungal alpha-tubulin sequences based on amino acid sequence homology and intron structure identified five groups of proteins. Group 1 consists of filamentous fungi, including S. tritici and R. secalis, the dimorphic fungus Histoplasma capsulatum, and Pneumocystis carinii. Group 2 includes two divergent isoforms from Neurospora crassa and Aspergillus nidulans. Group 3 includes the yeast Saccharomyces cerevisiae and the dimorphic fungus Candida albicans. Group 4 contains the single yeast Schizosaccharomyces pombe. Group 5 includes the only Basidiomycete, Schizophyllum commune. This analysis supports the classification of P carinii as a primitive Ascomycete. The presence of an additional glycine residue between the second and third amino acid found only in Group 2 proteins may indicate a functionally distinct fungal isotype. Implications in terms of structure-function relationships for alpha-tubulin molecules are discussed.

Amino Acid Sequence↗

PubMed1998

Expression of phosphatidylethanolamine-binding protein in the male reproductive tract: immunolocalisation and expression in prepubertal and adult rat testes and epididymides.

Phosphatidylethanolamine-binding protein (PBP) has been described previously in the male reproductive tract, where it has been implicated in the biogenesis and maintenance of antigen segregation of membranes. In the present study we have used a specific antiserum to PBP to determine its expression and localisation in the adult and prepubertal rat testis and epididymis by Western blotting and immunohistochemistry. In the adult rat testis, PBP was localised to step 17-19 elongating spermatids, residual bodies, and interstitial Leydig cells. In the adult epididymis, PBP was localised to epithelial cells of the caput, corpus, and cauda regions and to the cytoplasmic droplets of spermatozoa in the lumen of the initial segment, caput, and corpus epididymidis. In prepubertal animals, PBP was expressed in both testes and epididymides from day 1 and day 3 postpartum, respectively (day 3 being the earliest epididymal tissue taken). In prepubertal testes, PBP was localised to Leydig cells from day 1 postpartum and was not detected in any other cell type until the differentiation of elongate spermatids, when it was detected in step 17-19 elongating spermatids. These data suggest that PBP may be involved in the organisation of sperm membranes during spermiogenesis. The presence of PBP in Leydig cells, however, suggests diverse roles for this protein as a lipid carrier or binding protein.

Aging↗

PubMed1998

Sequence analysis of a variety of primate fertilin alpha genes: evidence for non-functional genes in the gorilla and man.

The sperm surface fertilin complex was first described in the guinea pig where it was found as a heterodimer of alpha and beta subunits, both of which were proposed to play a role in sperm-oolemma recognition and plasma membrane fusion during fertilisation. Whilst the beta subunit is apparently testis-specific, the finding of low levels of fertilin alpha in nonreproductive tissues has cast some doubt on a unique role in fertilisation. Moreover, the absence of a functional fertilin alpha gene in the human would imply that this gene product is not absolutely essential for fertilisation, although it could play a facilitatory role. We now describe the organisation and sequence of the fertilin alpha genes in a range of primates, including the great apes, and find that the gorilla gene, like that of the human, is non-functional.

ADAM Proteins↗

PubMed1998

MRI measurement of brain tumor response: comparison of visual metric and automatic segmentation.

An automatic magnetic resonance imaging (MRI) multispectral segmentation method and a visual metric are compared for their effectiveness to measure tumor response to therapy. Automatic response measurements are important for multicenter clinical trials. A visual metric such as the product of the largest diameter and the largest perpendicular diameter of the tumor is a standard approach, and is currently used in the Radiation Treatment Oncology Group (RTOG) and the Eastern Cooperative Oncology Group (EGOG) clinical trials. In the standard approach, the tumor response is based on the percentage change in the visual metric and is categorized into cure, partial response, stable disease, or progression. Both visual and automatic methods are applied to six brain tumor cases (gliomas) of varying levels of segmentation difficulty. The analyzed data were serial multispectral MR images, collected using MR contrast enhancement. A fully automatic knowledge guided method (KG) was applied to the MRI multispectral data, while the visual metric was taken from the MRI films using the T1 gadolinium enhanced image, with repeat measurements done by two radiologists and two residents. Tumor measurements from both visual and automatic methods are compared to "ground truth," (GT) i.e., manually segmented tumor. The KG method was found to slightly overestimate tumor volume, but in a consistent manner, and the estimated tumor response compared very well to hand-drawn ground truth with a correlation coefficient of 0.96. In contrast, the visually estimated metric had a large variation between observers, particularly for difficult cases, where the tumor margins are not well delineated. The inter-observer variation for the measurement of the visual metric was only 16%, i.e., observers generally agreed on the lengths of the diameters. However, in 30% of the studied cases no consensus was found for the categorical tumor response measurement, indicating that the categories are very sensitive to variations in the diameter measurements. Moreover, the method failed to correctly identify the response in half of the cases. The data demonstrate that automatic 3D methods are clearly necessary for objective and clinically meaningful assessment of tumor volume in single or multicenter clinical trials.

Adult↗

PubMed1998

Mentoring relationships of New Zealand nurses: results of an empirical study (Part 2).

The first national study of mentoring relationships of New Zealand nurses used three issues from the descriptive literature as its conceptual framework. The results and discussion of the study are reported in part two. Results demonstrated that moderate levels of mentoring according to Kram's (1985) typology occurred amongst nurses and that they had many supportive relationships, mainly with women who were peers. The characteristics of nurses' mentoring relationships did not differ significantly from mainstream empirical data when factors such as gender, organisational status, age differences and duration of relationships were considered. Concerns about the future direction of mentoring research and in particular about recent international literature calling for the development of a separate mentoring theory for women conclude the article.

Adult↗

PubMed1998

High level multiplex genotyping by MALDI-TOF mass spectrometry.

A primer extension assay is used to perform highly multiplexed genotyping of single nucleotide polymorphisms (SNPs) present in genomic DNA amplified by a multiplex PCR. The assay uses matrix-assisted laser desorption ionization time-of-flight mass spectrometry to accurately measure the masses of short oligonucleotide primers extended by a single dideoxynucleotide. The multiplexed genotyping assays rely on the natural molecular weight differences of DNA bases. By careful analysis of primer composition complementary to the target, or by judicious addition of one or more noncomplementary 5' bases to the genotyping primers, mass spectra of interleaved genotyping products can be generated with no ambiguity in allele assignment. Using a model multiplex PCR system, we demonstrate the ability to perform 12-fold multiplex SNP analysis.

Base Sequence↗

PubMed1998

Concurrent and predictive validity of an early language screening program.

The efficacy of screening 2-year-old children for language delay using a parent-report questionnaire was investigated in three studies. The Language Development Survey (Rescorla, 1989) was mailed to 650 families at the time of their child's second birthday. Fifty-three percent of the surveys received by parents were completed and returned. Screening outcomes were then compared, in double-blind fashion, with the results of comprehensive clinical evaluations at ages 2 (N = 64) and 3 (N = 36). Parents' report of the size of their children's expressive vocabularies was highly correlated with clinical language measures at age 2. Children who screened positive performed significantly poorer than children who screened negative on standardized language tests and on measures taken from spontaneous conversation. The screening program demonstrated excellent sensitivity and specificity for identifying language delay at age 2 but somewhat lower levels for predicting developmental status one year later.

Age Factors↗

PubMed1998

Expression of extracellular superoxide dismutase in the human male reproductive tract, detected using antisera raised against a recombinant protein.

Mammalian spermatozoa are particularly susceptible to the deleterious effects of reactive oxygen species and lipid peroxidation, which ultimately lead to impaired fertility. A number of enzymes are present in the male reproductive tract which may play a role in preventing oxidative damage; in particular, the epididymis is the site of synthesis and secretion of large amounts of extracellular superoxide dismutase (eSOD). In order to study the distribution of eSOD in the male reproductive tract, and distinguish it from other related superoxide dismutase isoenzymes (e.g. cytosolic SOD), polyclonal antisera have been raised against a recombinant human eSOD fusion protein, expressed in bacterial cells. This protein was expressed from a synthetic gene fragment, using preferred Escherichia coli codons, designed to overcome the problems associated with the high guanine+cytosine content of the natural human eSOD transcript. Using this antiserum, eSOD can be readily detected in a range of human reproductive tissues as well as in human seminal plasma. However, the presence of similar levels of eSOD in the seminal plasma of vasectomized men (probably of prostatic origin) precludes its use as a simple diagnostic indicator of eSOD activity levels in the epididymis.

Amino Acid Sequence↗

PubMed1998

Macaque MDC family of proteins: sequence analysis, tissue distribution and processing in the male reproductive tract.

A large number of sequence-related, cysteine-rich membrane proteins containing metalloproteinase-like and disintegrin-like domains (the MDC protein family) have been identified in mammalian tissues from a variety of species. Previous studies in the macaque (Macaca fascicularis) have led to the cDNA cloning and sequence analysis of a number of MDC proteins which are abundantly expressed in the male reproductive tract. We now describe the distribution of seven of these macaque MDC transcripts in a range of different tissues. This description includes a novel macaque testis-derived MDC, tMDC III, whose full-length sequence is reported for the first time. In addition, polyclonal antisera have been used to localize a number of these MDC proteins to spermatogenic cells in testis sections, and to demonstrate their processing on the sperm surface during epididymal transit.

ADAM Proteins↗

PubMed1998

Expression of extracellular glutathione peroxidase type 5 (GPX5) in the rat male reproductive tract.

The mammalian epididymis is the site of expression and secretion of an abundant, tissue-specific, androgen-regulated, selenium-independent, glutathione peroxidase isoenzyme (GPX5), which has been proposed to play a role in protecting the membranes of spermatozoa from the damaging effects of lipid peroxidation and/or preventing premature acrosome reaction. Using a combination of reverse transcription-polymerase chain reaction, Northern blot analysis and Western blotting, we now describe in detail the developmental expression of GPX5 transcripts and protein in the rat epididymis and characterize the association of rat GPX5 with the sperm plasma membrane.

Animals↗

PubMed1998

Fungal beta-tubulin, expressed as a fusion protein, binds benzimidazole and phenylcarbamate fungicides.

Benzimidazoles are important antitubulin agents used in veterinary medicine and plant disease control. Resistance is a practical problem correlated with single amino acid changes in beta-tubulin and is often linked to greater sensitivity to phenylcarbamates. This negative cross-resistance creates opportunities for durable antiresistance strategies. Attempts to understand the molecular basis of benzimidazole resistance have been hampered by the inability to purify tubulin from filamentous fungi. We have overcome some of these problems by expressing beta-tubulin as a fusion with a maltose binding protein. This fusion protein is soluble, and we confirm for the first time using a gel filtration assay that benzimidazoles indeed bind to beta-tubulin. This binding is reduced by the mutation Glu198-->Gly198, which also confers resistance. Binding of phenylcarbamates is the complete opposite, reflecting their biological activity and the negative cross-resistance. This suggests that the fungicide binding sites fold correctly in the fusion protein.

Base Sequence↗