PubMed Health⌕ Search

Biomedical subjects

E Baillie

Publications and source records attributed to E Baillie.

15 recordsLinked to original sources

Human T cell receptor V alpha gene polymorphism.

The T cell receptor (TcR) is a heterodimer composed of an alpha,beta- or a gamma,delta-chain. The receptor is expressed on the cell surface in association with the CD3 complex, which in turn is composed of at least four chains (gamma, delta, epsilon, and zeta). In this review, we will summarize the recent findings on the genomic organization of the four T cell receptor genes, and the polymorphisms detected in the variable regions of these genes.

DNA Probes↗

Polymorphism of the human T cell receptor alpha chain variable genes: identification of a highly polymorphic V gene probe.

In this study, we report the RFLP of the human T cell receptor (TCR) alpha chain variable gene segments. Using DNA samples from 20 individuals and three restriction endonucleases (BamHI, EcoRI and HindIII), the degree of RFLP of a number of different V gene segments was defined. Half of the V alpha subfamilies (6/12) were characterized by a predominant hybridization pattern, with only a few individuals displaying a second pattern. However, one particular V gene family, V alpha 6, has at least five allelic forms that segregated consistently in familial studies. The V alpha polymorphisms revealed in this study, together with those exhibited by V beta gene subfamilies, should prove useful in studying possible associations between TCR gene usage and disorders of the immune system.

Alleles↗

The human T cell receptor alpha-delta locus: a physical map of the variable, joining and constant region genes.

In this study a physical macro-restriction map of the entire human alpha locus that spans about 1000 kilobase pairs and includes the V alpha, J alpha and C alpha genes is presented. Evidence is provided that gene duplications were involved in the increase of genomic diversity of V alpha genes. In addition, we show a detailed map of a 40-kb region located approximately 100 kg upstream of the human C alpha gene. Direct evidence is provided to support that the human alpha chain locus, like the murine, also contains another T cell constant region gene in the alpha chain locus, the human delta chain gene. In addition, two J segments and one D segment have been identified. Using these genomic probes, we show that several T cell lines, including those known to express the surface gamma/delta heterodimer, have rearranged this region. The design of two separate centers of rearrangement within one locus that are involved in rearrangement events at different times, and the presence of high number of J segments in this region, may render the locus highly vulnerable to chromosomal translocation during T cell development.

Cell Line↗

Sustained release oral aminophylline in patients with airflow obstruction.

Twenty-four patients with reversible airflow obstruction under suboptimal control on conventional therapy entered a double-blind placebo-controlled trial of additional oral sustained release aminophylline. Assessment was by diary cards, twice daily PEFR, and weekly FEV1. Nineteen patients completed the trial satisfactorily. Eleven were improved subjectively by addition of aminophylline. The mean PEFR for all 19 patients rose from 232 1 min-1 SEM +/- 5, to 247 1 min-1 SEM +/- 4 (p less than 0.0001); nine individuals showed a statistically significant improvement in mean PEFR and 10 showed an improvement of greater than 200 ml in their FEV1. Improvement in PEFR on aminophylline was not at the expense of benefit from inhaled salbutamol. Unwanted effects of nausea, headache, and abdominal discomfort were recorded by 12 of the 24 patients entering the trial. Seventeen of the 19 patients completing the trial had plasma theophylline levels in the accepted therapeutic range of 10-20 mg 1(-1). The drug doses required to achieve these levels varied from 8.6-30.8 mg kg-1 24 hr-1 in the patients with no clinical or biochemical evidence of liver disease. Oral aminophylline can improve control of airflow obstruction in patients with moderately severe disease who are already receiving multiple medication, but side-effects often limit its use. The wide dose range required to achieve therapeutic plasma levels indicates that measurements of plasma theophylline are necessary for adequate interpretation of trials of theophylline compounds.

Adult↗

Dosage schedule for intravenous aminophylline in apnoea of prematurity, based on pharmacokinetic studies.

15 preterm infants were treated for recurrent apnoea with theophylline. 5 were given oral choline theophyllinate, but this was erratically absorbed. 14 were given IV aminophylline on 23 occasions. Apparent volume of distribution of theophylline in 12 infants was 0.71 +/- 0.18 1/kg (mean +/- SD). Plasma clearance rate measured in 11 infants at steady state was 18.6 +/- 4.8 ml/kg per hour. Calculations show that a loading dose of 6.2 mg/kg aminophylline intravenously and maintenance of 4.4 mg/kg per day would produce serum levels of between 6 and 12 mg/l in all but one of the infants studied, with no infant having toxic levels.

Aminophylline↗

A double-blind trial of oral aminophylline (Phyllocontin Continus tablets) in airflow obstruction: preliminary communication.

Twenty-two patients with reversible airflow obstruction were entered into a double-blind crossover trial of Phyllocontin Continus tablets and placebo to assess the additional benefit of the controlled-release aminophylline preparation when added to the patients' medication. Most patients were taking inhaled or oral steroids in addition to inhaled beta-sympathomimetics throughout the trial. The dosage of Phyllocontin tablets was adjusted in a pre-trial study to provide serum theophylline levels in the accepted therapeutic range of 10--20 mg/l. In the seventeen patients who completed the 8-week study a small, but significant, increase in both the patients' own recordings of PEFR and weekly clinic measurements of FEV1 was seen whilst on the active drug. Ten patients had improvement in FEV1 greater than 200 ml. Eleven patients recorded subjective improvement on the active drug and five out of ten patients who used inhaled beta-sympathomimetics p.r.n. showed a reduction in their usage of greater than 10%. Side-effects were reported by twelve patients.

Adult↗

A comparison of oral choline theophyllinate and beclomethasone in severe perennial asthma in children.

Fourteen children with perennial asthma previously treated with beclomethasone dipropionate were studied for four months in a crossover trial to compare the efficacy of choline theophyllinate and beclomethasone dipropionate aerosol in the control of their symptoms. Assessments were made using twice daily peak flow measurements, together with daily records of symptom scores and use of extra salbutamol. Beclomethasone and oral choline theophyllinate together improved control of asthma in comparison with beclomethasone alone. Reduction of the dose of beclomethasone from 400 microgram/day caused worsening of asthma. Oral choline theophyllinate did not prevent this deterioration and therefore cannot replace beclomethasone for the long-term treatment of such asthmatic patients.

Administration, Oral↗

Serum theophylline levels in asthmatic children after oral administration of a slow-release aminophylline preparation (Phyllocontin Continus tablets).

Twenty-seven asthmatic children aged 3--14 years who were considered to need continuous treatment were studied. Fifteen received a low dose of slow-release aminophylline and fifteen a high dose. There was a wide range of serum theophylline levels between individuals for similar doses. Fourteen of twenty children who had five or more levels measured throughout the day had differences between maximum and minimum levels of greater than 4 microgram/ml. The peak levels occurred between 2 and 6 hours after the dose. Only four children had levels exceeding 20 microgram/ml and none was symptomatic. We suggest a dose of 14 mg/kg/dose twice daily which should be reviewed after peak serum theophylline levels are measured.

Adolescent↗

Serum theophylline levels in asthmatic children after oral administration of two slow-release theophylline preparations.

Serum theophylline levels were measured throughout the day in 65 asthmatic children receiving one of two slow-release theophylline compounds. There was a wide interindividual variation in levels obtained with similar doses of pure theophylline, and also a wide intraindividaual variation in levels throughout the day, suggesting that the rates of release and/or absorption of theophylline from these compounds are not uniform. There were fewer side effects associated with taking these compounds than with choline theophyllinate.

Administration, Oral↗

Effect of practical timing of dosage on theophylline blood levels in asthmatic children treated with choline theophyllinate.

Two dosage schedules, 8 mg/kg per dose daily and 10 mg/kg per dose tds of choline theophyllinate were evaluated in asthmatic children. The times of the doses were considered the most practical for use outside hospital. Theophylline levels were measured 2 hours after each dose and were satisfactory in both schedules. The levels before the first dose of the day were, however, unsatisfactory. We emphasis the desirability of measuring blood levels in any patient receiving a theophylline compound.

Administration, Oral↗

Clinical applications of serum theophylline measurement by high pressure liquid chromatography.

Serum theophylline concentration was measured in children both during treatment of status asthmaticus with intravenous aminophylline, and as outpatients while they were taking oral theophylline compounds for long-term management of asthma. The clinical value of the measurements was assessed. Measurement using high-pressure liquid chromatography is simple and requires only a small volume of blood. Knowledge of serum theophylline concentration facilitates careful control of dosage of both intravenous aminophylline during treatment of status asthmaticus, and of oral theophylline in outpatients. It is useful in the evaluation of symptoms which may be due to toxic side effects of treatment. It also makes possible an assessment of patient compliance with prescribed treatment among those whose symptoms have not improved.

Adolescent↗

Heat-induced requirements for sucrose or magnesium for expression of heat resistance in Bacillus cereus forespores.

The addition of 0.6 M sucrose of 0.016 M Mg2+ to the enumeration medium was required for early expression of heat resistance (10 min at 70 degrees C) in stage V Bacillus cereus forspores. The addition of Mg2+ to the sporulation medium did not remove this requirment for sucrose of Mg2+. The heat damage did not affect forespore germination or outgrowth, but injured cells in the absence of sucrose or Mg2+ were not capable of cell division. The heat-induced sublethal damage apparently affected the forspore component(s) that could be repaired or was capable of normal function in the presence of added Mg2+ or sucrose.

Bacillus cereus↗

Photoreactivation, photoproduct formation, and deoxyribonucleic acid state in ultraviolet-irradiated sporulating cultures of Bacillus cereus.

Photoreactivation of ultraviolet-irradiated Bacillus cereus T declined markedly during the development of stage IV forespores. During ultraviolet irradiation of a culture containing early and late stage IV forespores, both vegetative- and spore-type photoproducts were formed. The formation of vegetative-type photoproducts (mainly thymine dimers) decreased to nearly half during late stage IV, remaining constant until lysis of the mother cells began, when it fell to zero. Spore-type photoproducts were first observed during late stage IV and increased with the increase in numbers of late stage IV forespores. The occurrence of spore-type photoproducts preceded the development of refractile forespores by about 1 h. At stage III the nuclear material occupied a central position, and the ribosomes were at the periphery of the forespore protoplast. During stage IV the deoxyribonucleic acid (DNA) occurred in a peripheral position, and bundles of fibers ("transition" DNA) could be seen. By stage V, all of the DNA appeared to be of the spore type and was peripheral, and the forespore protoplast center was packed with ribosomes. Forespore stages II, III, and IV were classified by light and electron microscopy. The curve for electron microscope classifications preceded that for light microscope classifications by approximately one stage. The formation of spore-type photoproducts preceded differentiation of DNA by about 1 h, the latter coinciding with the development of refractility. Spore-type photoproducts have been associated with DNA in the A state, and the progressive change of the forespore DNA into this state is discussed in relation to the spore differentiation process.

Bacillus cereus↗