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Biomedical subjects

L Llewellyn

Publications and source records attributed to L Llewellyn.

15 recordsLinked to original sources
PubMed2001

Characterization of a sea bream (Sparus aurata) thyroid hormone receptor-beta clone expressed during embryonic and larval development.

A clone encoding thyroid hormone receptor-beta (TR-beta) was isolated from a sea bream (Sparus aurata) ovary cDNA library. Sea bream (sb)TR-beta is closely related to its counterparts from other vertebrates and, like them, preferentially binds T3 rather than T4. However, the putative sbTR-beta protein contains a nine-amino-acid insert that is also present in the corresponding proteins from flounder and salmon but absent in TR-betas from zebrafish and terrestrial vertebrates. Semiquantitative RT-PCR analysis showed that sbTR-beta transcripts begin to accumulate during gastrulation and increase markedly in quantity up to the period around hatch (ca. 40 h postfertilization) before declining slightly. In adult tissues, TR-beta mRNA was present in approximately equal quantities in heart, intestine, brain, kidney, skeletal muscle, liver, and gill. The significance of the relatively strong expression of TR-beta during sea bream embryogenesis is discussed.

Amino Acid Sequence↗
PubMed2001

Thyroid hormones in growth and development of fish.

The thyroid hormones (THs), thyroxine (T(4)) and triiodothyronine (T(3)) are products of the thyroid gland in all vertebrates. Their role in early development and metamorphosis is well established in mammals and amphibians, respectively, and recently several studies in fish have highlighted the importance of THs during flatfish metamorphosis. THs are present in high quantities in fish eggs and are presumably of maternal origin. During embryogenesis the concentration of T(4) and T(3) in the eggs decrease until endogenous production starts. Thyroid hormone receptors (TR) have been isolated from several teleosts and in common with tetrapods two receptor isoforms have been identified, TR alpha and TR beta. Both the receptors are expressed in early embryos and larvae of the Japanese flounder (Paralichthys olivaceus), zebrafish (Danio rerio) and seabream (Sparus aurata) although a different temporal pattern is apparent. The role of THs and TRs in fish embryogenesis, larval development and during metamorphosis will be discussed.

Amino Acid Sequence↗
PubMed2000

Cloning and Expression of an Elongation Factor-1alpha in Sea Bream (Sparus aurata) Larvae and Adult Tissue.

A clone encoding the polypeptide elongation factor EF-1alpha was isolated from a complementary DNA library prepared from sea bream (Spartus aurata) larvae 1 to 10 days after hatching. The deduced amino acid sequence is between 82% and 95% similar to EF-1alpha in other animal species. EF-1alpha messenger RNA is present at low abundance in sea bream embryos prior to gastrulation, but at around 15 hours postfertilization, there is a 10-fold increase in transcript levels. This increase presumably reflects midblastula transition in this species. In adult sea bream, EF-1alpha appeared to have a relatively uniform distribution across all the tissues analyzed.

Journal Article↗
PubMed2000

Cloning of the Atlantic salmon (Salmo salar) estrogen receptor-alpha gene.

A cDNA clone encoding most of an Atlantic salmon (Salmo salar) estrogen receptor (ER) was obtained from a liver cDNA library and the remainder of the coding sequence from the gene was isolated from a genomic library. Sequence comparisons showed that the cloned gene represents ER-alpha. Expression of the ER-alpha gene in male and female salmon parr was analysed by RT-PCR. Highest expression was found in brain and liver, with lower levels of ER-alpha mRNA present in all other tissues tested. There was little difference in expression of ER-alpha between male and female.

Amino Acid Sequence↗
PubMed1999

Community care. Home service.

A nurse-led scheme to prevent hospital admissions by providing emergency services in the community for up to 72 hours cared for 155 people in its first six months. The scheme operated well below full capacity partly because of initial opposition from GPs. The mean age of service users was 79 and the main reasons for referral were chest infections, pneumonia and the need for support following an injury. More than three quarters of those cared for were fit to be discharged from the scheme within 72 hours.

Aged↗
PubMed1998

Cloning and unusual expression profile of the aldolase B gene from Atlantic salmon.

A full-length clone of the aldolase B gene has been isolated from a cDNA library constructed from liver of Atlantic salmon (Salmo salar). Sequencing showed that the clone encodes a typical aldolase B, possessing a number of amino acid residues which are seen in aldolase B, but not in other aldolase isoforms. RT-PCR analysis showed that the gene is expressed in liver, kidney and intestine as expected. However, in contrast to mammalian and avian aldolase B, expression was also found in a number of other tissues. Levels of aldolase B mRNA in liver and kidney were not significantly altered during smoltification, the transformation of freshwater-dwelling salmon (parr) into saltwater-adapted salmon (smolts).

Amino Acid Sequence↗
PubMed1998

Cloning, characterisation and expression of the apolipoprotein A-I gene in the sea bream (Sparus aurata).

A full length cDNA clone representing apolipoprotein A-I was isolated from a sea bream (Sparus aurata) liver library. The clone encodes a 261 amino acid protein which shows highest amino acid identity (38%) with salmon apolipoprotein A-I. Northern blot analysis showed strong expression of a 1.4 kb transcript in liver with lower expression in intestine. Expression of apolipoprotein A-I in intestine was markedly reduced by treatment with triiodothyronine (T3).

Amino Acid Sequence↗
PubMed1998

Comparative analyses by HPLC and the sodium channel and saxiphilin 3H-saxitoxin receptor assays for paralytic shellfish toxins in crustaceans and molluscs from tropical North West Australia.

The increased frequency and distribution of red tides requires the development of high-throughput detection methods for paralytic shellfish toxins (PST). Community ethics also requires that there be a reduced reliance upon the standard mouse bioassay. A biomolecular assay such as the sodium channel 3H-saxitoxin binding assay can satisfy both of these requirements but may be compromised by cross-reactivity with the structurally unrelated tetrodotoxins (TTX). This study utilised the sodium channel assay but also an alternative 3H-saxitoxin binding assay based upon a saxiphilin isoform from the centipede Ethmostigmus rubripes to screen for PSTs. Saxiphilin is a novel transferrin which binds saxitoxin (STX) but differs from the sodium channel in not having any measurable affinity for TTX. A detailed analysis of toxin composition was achieved by high performance liquid chromatography (HPLC). Various crustaceans and molluscs accumulate PSTs and TTX, thus proving useful biomarkers for these toxins in their immediate environment and an ideal challenge to the detection and analysis of PSTs in this presumptive screening program. Also, there has been little investigation of PSTs in invertebrates from the Indian Ocean so this region was selected to extend our knowledge of the distribution of these toxins. 190 crabs and shellfish encompassing 31 species were collected from reefs along the North-West Australian coast and tested for PSTs and TTX by sodium channel and saxiphilin bioassays as well as HPLC. PSTs were detected in 18 species of crabs and shellfish of the 31 species tested. Eight of these species have not been previously described as toxic, these being the crabs Euzanthus exsculptus, Lophozozymus octodentatus, Metopograpsus frontalis, Pilumnus pulcher, Platypodia pseudogranulosa and Portunus pelagicus, and the molluscs Tectus fenestratus and Trochus hanleyanus. By HPLC, only one or both of STX and decarbamoyl-STX was detected in any extract. Some extracts markedly inhibited 3H-saxitoxin binding by the sodium channel but not by saxiphilin. The close agreement between toxin quantification by the PST specific methods of HPLC and the saxiphilin bioassay is indicative that the additional toxicity detected by the sodium channel assay is TTX.

Amphibian Proteins↗
PubMed1997

Cloning and sequencing of a full-length sea bream (Sparus aurata) beta-actin cDNA.

A full-length cDNA clone encoding beta-actin (beta-actin) was isolated from a sea bream (Sparus aurata) liver cDNA library. Sequencing of this clone reveals an open reading frame encoding a 375 amino acid protein that shares a high degree of conservation to other known actins. The sea bream beta-actin sequence showed 98% identity to carp and human beta-actin and 95% and 94% identity to sea squirt and Dictyostelium cytoplasmic actins, respectively.

Actins↗
PubMed1995

Cloning and characterisation of a fish aldolase B gene.

A full length cDNA clone representing an aldolase mRNA was isolated from a sea bream (Sparus aurata) liver cDNA library. Sequencing of this clone revealed it to encode a 364 amino acid protein with 74% amino acid identity to human aldolase B and slightly lower similarity to human aldolase A and C. In view of the sequence data and of Northern blot analysis showing strong expression of a 1.6 kb transcript in liver it was concluded that the cloned gene represents aldolase B. This clone represents the first aldolase gene to be sequenced from any fish species thus providing new data on the evolution of the vertebrate aldolase gene family.

Amino Acid Sequence↗
PubMed1993

Is there a right age for case finding in elderly people?

If age is a useful basis for determining a screening policy the benefit of the resulting interventions should vary with age. The choice of the screening age will be such as to maximize the benefit. Data from a study of the screening of elderly people by a Health Visitor produced no evidence to support the choice of 75 as minimum age for screening in primary care. Indeed there was a suggestion that age might be more useful as a maximum rather than a minimum criterion.

Aged↗
PubMed1993

Enhancing appropriateness of acute bed use: role of the patient hotel.

OBJECTIVE: This study aimed to assess the appropriateness of bed use by determining patients' suitability for patient hotel accommodation and day treatment and by examining timeliness of discharge, and to assess patient and staff views about patient hotels. DESIGN: Patients were assessed by a doctor and nurse in terms of an agreed case definition for patient hotel use. Patient suitability was validated and patient acceptability measured by semi-structured interviews with a random sample of patients judged suitable for hotel accommodation. All senior medical and nursing staff completed a further questionnaire. SETTING: The study took place at University Hospital of Wales, Cardiff (856 beds), and all specialties, except intensive care wards, participated. SUBJECTS: Patients occupying a total of 3972 bed days, accumulated over seven randomly chosen census days, were studied. RESULTS: Data were available for 88% of eligible inpatients. Ten per cent (405 of 3972) of patients were judged suitable for a patient hotel. Specialties indicating major use were obstetrics and gynaecology, general surgery, and general and geriatric medicine. Sixty three per cent (254 of 405) of these subjects required low level investigation or treatment. Preoperative and postoperative and antenatal patients were often suitable also. Three per cent (119 of 3972, 95% confidence interval 2.5, 3.6%) of inpatients were judged suitable for day treatment/investigation. Seventy nine per cent (291 of 369) of patients suitable for discharge were discharged on the same or the next day. The patient hotel idea was acceptable to 58 of 68 (85%) randomly selected patients and to 84 of 93 (90%) staff. CONCLUSIONS: With allowance for non-response, our study indicates that a general hospital of this size generates the need (inpatients, relatives, and ward attenders) for a mean of 72 patient hotel beds. There is also residual scope for increasing day treatment/investigation and for releasing beds by speeding discharge. The patient hotel idea is highly acceptable to both patients and staff and should be widely considered as a means of making patient care more efficient.

Adolescent↗
PubMed1993

Biochemical and immunochemical comparison of saxiphilin and transferrin, two structurally related plasma proteins from Rana catesbeiana.

Saxiphilin is a approximately 90-kDa protein in bullfrog plasma that binds the neurotoxin saxitoxin (STX) with high affinity (Kd, approximately 0.2 nM). The relationship between saxiphilin and transferrin was examined because partial sequencing of saxiphilin previously revealed an unexpected homology to members of the transferrin family of Fe(3+)-binding proteins. Transferrin was purified from bullfrog plasma and shown to be distinct from saxiphilin on the basis of its size (approximately 78 kDa), chromatographic behavior, visible absorption spectrum, and ligand-binding properties. High affinity binding of [3H]STX was found to be a distinctive property of saxiphilin that was not exhibited by transferrins from various species of animals. Conversely, under conditions appropriate for transferrins, purified saxiphilin did not bind 55Fe3+, implying that it is not involved in iron metabolism. Polyclonal antibodies raised against native saxiphilin precipitated [3H]STX-binding activity from whole bullfrog plasma. On immunoblots such antibodies recognized the denatured saxiphilin protein but only weakly labeled bullfrog transferrin. In an enzyme-linked immunosorbent assay using native proteins, antisaxiphilin antibodies weakly cross-reacted with transferrin from bullfrog and a number of other species. Likewise, antibodies against human transferrin cross-reacted with saxiphilin in a similar immunosorbent assay. These results lead to the conclusion that saxiphilin is not bullfrog transferrin but is structurally related to the transferrin family. As a novel member of the transferrin superfamily, saxiphilin may help to uncover new functions mediated by this class of proteins.

Amphibian Proteins↗
PubMed1992

Supporting elderly dependent people at home.

OBJECTIVE: To clarify the relation between the dependency of elderly people and the assistance they receive from others by using a detailed but simple measure of dependency. DESIGN: Secondary analysis of data from a survey of people aged 70 and over. SETTING: Two general practices in south Wales. SUBJECTS: 1280 people aged 70 and over. MAIN OUTCOME MEASURES: Dependency on others to perform essential functions; detailed data on who assists with those functions. RESULTS: Increasing dependency was associated with increased use of more than one member of the family or friends and an increase in the provision of statutory services. CONCLUSION: The complexity of the relation between dependency and those who care for dependent people has previously been underestimated. The presence of providers of statutory services at the household of elderly dependent people suggests that these services can be developed further to help those caring for elderly people at home.

Activities of Daily Living↗