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Biomedical subjects

D H Boyd

Publications and source records attributed to D H Boyd.

At least 19 recordsLinked to original sources
PubMed2001

Comprehensive identification of conditionally essential genes in mycobacteria.

An increasing number of microbial genomes have been completely sequenced, and the identified genes are categorized based on their homology to genes of known function. However, the function of a large number of genes cannot be determined on this basis alone. Here, we describe a technique, transposon site hybridization (TraSH), which allows rapid functional characterization by identifying the complete set of genes required for growth under different conditions. TraSH combines high-density insertional mutagenesis with microarray mapping of pools of mutants. We have made large pools of independent transposon mutants in mycobacteria by using a mariner-based transposon and efficient phage transduction. By using TraSH, we have defined the set of genes required for growth of Mycobacterium bovis bacillus Calmette-Guérin on minimal but not rich medium. Genes of both known and unknown functions were identified. Of the genes with known functions, nearly all were involved in amino acid biosynthesis. TraSH is a powerful method for categorizing gene function that should be applicable to a variety of microorganisms.

Base Sequence↗
PubMed2000

A prospective study of factors affecting survival of replanted permanent incisors in children.

OBJECTIVE: To examine the factors associated with the onset of resorption in replanted avulsed permanent incisor teeth and to demonstrate their patterns of survival free of resorption. SETTING: Department of Paediatric Dentistry, Belfast. DESIGN: Prospective recording of the timing of the injury and of replantation, the storage media, the degree of root development and contamination, and the completion of root treatment. Clinical and radiographic reviews at 3-month intervals. Root resorption classified as replacement and inflammatory. Logistic regression and survival curves with freedom from resorption as outcomes. RESULTS: In 50 avulsed incisors in children aged 6-16 years the best predictor of overall resorption was total time of dryness, and that for replacement resorption was total extra-oral time. The timing of detection of resorption varied from 102 days to 997 days. CONCLUSION: Both total extra-oral time and time stored dry are important factors for the onset of resorption in replanted avulsed teeth in children.

Adolescent↗
PubMed1999

Inflammatory and replacement resorption in reimplanted permanent incisor teeth: a study of the characteristics of 84 teeth.

Avulsion is a serious injury which can cause damage to some or all of the dental and surrounding tissues. This study examined the profiles of teeth showing inflammatory resorption, in terms of time prior to reimplantation, contamination, pulp extirpation time and period of splinting and compared them to teeth without resorption. There were a total of 71 children in the present study (mean age 9.8 years, range 6-16 years) with a total of 84 reimplanted teeth. Inflammatory resorption was present in 22 teeth. There was a significant relationship between the presence of inflammatory resorption and the time the teeth were dry prior to reimplantation, with a lesser effect for total delay time. There were slightly later pulp extirpation times for teeth with inflammatory resorption, with median delays of 16 and 11 days respectively and increased inflammatory resorption in teeth extirpated at 20 days or later. Replacement resorption was present in 40 teeth. There was a significantly longer splinting time in teeth with replacement resorption and more resorption in teeth splinted for longer than 10 days. It was concluded that pulp extirpation time was not critical unless the delay exceeded 20 days and that splinting time should not exceed 10 days.

Adolescent↗
PubMed1998

The protein translocation apparatus contributes to determining the topology of an integral membrane protein in Escherichia coli.

The assembly of integral membrane proteins is determined by features of these proteins and the protein translocation apparatus. We used alkaline phosphatase fusions to the membrane protein MalF to investigate the role of the protein translocation machinery in the arrangement of proteins in the cytoplasmic membrane of Escherichia coli. In particular, we studied the effects of prlA mutations on membrane protein topology. These mutations lie in the secY gene, which encodes a core component of the protein translocation apparatus. We find that the topology of some of the fusion proteins is changed and, in one case, is completely inverted in prlA mutants. We discuss the mechanism of prlA-mediated export and the role of the protein translocation apparatus in contributing to membrane protein topology.

Bacterial Proteins↗
PubMed1996

A computer software package to facilitate clinical audit of outpatient paediatric dentistry.

This paper reports the development and function of a computer program for clinical audit of outpatients in hospital paediatric dentistry in the United Kingdom. The project was one of several national audit projects supported by the Faculty of Dental Surgery, Royal College of Surgeons of England, and funded by the Department of Health. The software is designed to record data utilizing a nationally-agreed minimum set of codes for dental diagnosis, treatment and medical complications, together with patient demographic details pertaining to source of referral, age and sex of patient, and area of residence. A significant component of the software is a flexible report generator which allows data to be analysed using any combination of the above criteria. Audit of activity in hospital dentistry is desirable to enable comparisons to be made between groups of patients and treatments related to diagnosis. This provides the information necessary to enable improvements in clinical practice whilst also assisting the development of both local and national clinical guidelines. Use of this software package will enable such comparisons to be made not only within one hospital but also between different hospital and regions in the United Kingdom.

Ambulatory Care↗
PubMed1995

Candida infection of a persistent palatal ulcer in a 20-month-old child.

A 20 month-old infant presented with a painless, persistent lesion on the hard palate which had been present for 6 months. The lesion was aggressive in appearance, approximately 2 cm in diameter with raised, rolled edges, and there was what appeared to be granulation tissue present together with some necrotic slough in its base. It was considered to represent a traumatized area with superimposed secondary Candida infection. A direct smear of the lesion was positive for Candida. Antifungal therapy, and an attempt to avoid further irritation by advising the mother not to give the child a feeding bottle whenever possible, resulted in complete healing of the lesion. There has been no recurrence in 2 years.

Antifungal Agents↗
PubMed1981

Plasma thiamin pyrophosphate and erythrocyte transketolase in chronic alcoholism.

Thiamin status in patients with an alcohol problem was studied before and after intramuscular thiamin hydrochloride. Results for erythrocyte transketolase activity and plasma thiamin pyrophosphate are compared. Plasma thiamin pyrophosphate values for healthy human subjects are reported for the first time. Advantages of plasma thiamin pyrophosphate in the assessment of thiamin status of patients are discussed.

Alcoholism↗
PubMed1981

The nutritional status of patients with an alcohol problem.

73 patients with an alcohol problem seen in a hospital medical unit over a two year period were examined specifically for signs suggestive of nutritional deficiency and of organ or system damage due to alcohol. A seven day dietary recall was carried out on most of them. Clinical signs of nutritional deficiency were relatively uncommon but nine patients had Wernicke-Korsakoff syndrome and ten had peripheral neuropathy. Thiamine was present in less than recommended amounts in 81.5% of the diets. Vitamin D and vitamin C were the next most common dietary deficiencies. 66.1% were deficient in energy intake and about a third of patients derived more than 40% of their energy from alcohol.

Adult↗
PubMed1977

The pneumonias.

Explore the source record for details and available documents.

Humans↗
PubMed1977

Release of Escherichia coli DNA from membrane complexes by single-strand endonucleases.

Treatment of gently prepared lysates of Escherichia coli with single-strand-specific endonuclease (SI or from mung beans) results in the release of about 90% of the DNA from membranes, as determined by the M band technique. The released DNA has an average molecular weight of about 1.2 X 10(8). Data obtained with endonuclease S1 fit a mathematical model in which substrate sites are at or near membrane attachment sites. Data obtained with pancreatic deoxyribonuclease or x-rays fit a model for double-strand breaks at random sites along the DNA. Fitting data to these models, we estimate that there are 18+/-5 membrane attachment sites. The DNA remaining after S1 nuclease treatment is enriched for the region near the origin of chromosome replication. Therefore, attachment at this region near the origin of chromosome replication. Therefore, attachment at this region appears to be chemically different from that at the other sites along the DNA.

Animals↗
PubMed1976

Sea-blue histiocytosis associated with hyperlipidaemia.

A patient with sea-blue histiocytosis in spleen and bone marrow with an accompanying hyperlipidaemia is described. The hyperlipidaemia was due to an increase in "free" cholesterol, lecithin, and triglycerides. Despite these findings lecithin-cholesterol acyl transferase activity was normal. Although the precise biochemical defect was not identified, there was a failure of transport of cholesterol from chylomicrons in vitro. We propose that the sea-blue histiocyte is a marker, in some cases, of abnormal lipid metabolism.

Adult↗