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Biomedical subjects

R Milne

Publications and source records attributed to R Milne.

At least 91 records · Page 5Linked to original sources
PubMed1993

Waits and measures.

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Health Care Rationing↗
PubMed1993

Purification and characterization of a trypsin-like digestive enzyme from spruce budworm (Choristoneura fumiferana) responsible for the activation of delta-endotoxin from Bacillus thuringiensis.

A trypsin-like enzyme purified from spruce budworm (Choristoneura fumiferana) gut juice has a molecular mass of 25 kDa and its pH activity profile indicates a pKa of 8. Sequence homology with bovine trypsin of the N-terminus and active site, and the ionization dependence for catalysis, reflect the typical trypsin-like activities measured. The action of this enzyme (designated CFT-1) is compared to the neat gut juice with regard to the proteolytic activation of the delta-endotoxin from Bacillus thuringiensis.

Amino Acid Sequence↗
PubMed1992

Comparative toxicity of the HD-1 and NRD-12 strains of Bacillus thuringiensis subsp. kurstaki to defoliating forest Lepidoptera.

Insecticidal activities of sporulated cultures of the HD-1 and NRD-12 strains of Bacillus thuringiensis subsp. kurstaki were compared against four species of defoliating forest lepidopterans in diet-incorporation assays. There was no difference in LC50 between the two strains to larvae of spruce budworm (Choristoneura fumiferana), gypsy moth (Lymantria dispar), eastern hemlock looper (Lambdina fiscellaria fiscellaria), and whitemarked tussock moth (Orgyia leucostigma), whether expressed as total alkaline soluble protein, activated toxin protein, or International Units as determined by bioassay against Trichoplusia ni. Both strains were consistently more toxic than HD-1-S-1980 when compared on the basis of alkali-soluble protein, but not on the basis of activated toxin or International Units. Hybridization of genomic DNA after restriction with HindIII revealed the presence of all three cryIA toxin genes in each of the isolates used in this study, including HD-1-S-1980, which was previously reported to have lost the cryIA(b) gene.

Animals↗
PubMed1992

Pollution in the upland environment.

As part of a study on the effects of pollutants on forests, a long-term monitoring programme has been operating at two sites (602 and 275 m above sea level (a.s.l.)) in Glentress Forest, south-east Scotland, since June 1987. At these sites, equipment has been recording 20-min data for weather parameters, and cloud and rain event frequency, duration and intensity. The chemical composition of bulk cloud and rainwater has been measured. Cloudwater detection and collection has been made using passive 'Harp wire' gauges (with a cross-sectional area of 0.047 m2) strung with polypropylene filament and having a typical collection efficiency of 29% when compared with independent measurements of windspeed and liquid water content. During 1988, the annual rainfall at the upper site was 1213 mm, occurring over 1776 h. The equivalent cloudwater deposition to a forest with a drag coefficient of 0.06 was estimated to be 375 mm over 1936 h. A 'typical cloud event' lasted 4.5 h and would deposit to forests at a rate of 0.2 mm h(-1). There were significantly higher loadings of suspended particulate material (> 0.2 microm) in cloudwater (mean 18.42, max. 94.5 mg litre(-1)) compared with rainwater (mean 2.6, max. 25.6 mg litre(-1)). There were similar differences in ion concentrations, e.g. for H+ in cloudwater (mean 163, max. 1259 microm) and in rainwater (mean 33, max. 262 microM). It is concluded that cloudwater deposition represents a major pathway for pollutant transfer to the upland environment, especially where the surface vegetation is efficient at capturing cloudwater, i.e. forests. The consequences of this increased pollutant loading to forests and water catchments are yet to be assessed.

Journal Article↗
PubMed1992

Venous thromboembolism and travel: is there an association?

This paper reviews the literature on the association between venous thromboembolism and travel. There are plausible physiological reasons why sitting still for long periods (particularly in the cramped conditions of most aircraft) might predispose to venous thromboembolism. This may have been the explanation for the apparent excess of deaths from pulmonary embolism seen during the first months of the London blitz. No published controlled studies of thromboembolism and travel were identified, but eight case reports were analysed. They covered 25 people aged from 19 to 84 years with deep vein thrombosis or pulmonary embolism following travel. The reports suggest that long journeys are a particular risk and that there are often no symptoms until many hours after leaving the plane (so conventional methods of assessing the hazards of air travel may underestimate the problem). It is concluded that the literature tends to support the hypothesis that venous thromboembolism is associated with travel, but that carefully controlled studies are needed to test this properly.

Adult↗
PubMed1991

Functional domains of Bacillus thuringiensis insecticidal crystal proteins. Refinement of Heliothis virescens and Trichoplusia ni specificity domains on CryIA(c).

Insecticidal crystal proteins (delta-endotoxins), CryIA(a) and CryIA(c), from Bacillus thuringiensis are 82% homologous. Despite this homology, CryIA(c) was determined to have 10-fold more insecticidal activity toward Heliothis virescens and Trichoplusia ni than CryIA(a). Reciprocal recombinations between these two genes were performed by the homolog-scanning technique. The resultant mutants had different segments of their primary sequences exchanged. Bioassays with toxin proteins from these mutants revealed that amino acids 335-450 on CryIA(c) are associated with the activity against T. ni, whereas amino acids 335-615 on the same toxin are required to exchange full H. virescens specificity. One chimeric protein toxin, involving residues 450-612 from CryIA(c), demonstrated 30 times more activity against H. virescens than the native parental toxin, indicating that this region plays an important role in H. virescens specificity. The structural integrity of mutant toxin proteins was assessed by treatment with bovine trypsin. All actively toxic proteins formed a 65-kDA trypsin-resistant active toxic core, similar to the parental CryIA(c) toxin, indicating that toxin protein structure was not altered significantly. Contrarily, certain inactive mutant proteins were susceptible to complete protease hydrolysis, indicating that their lack of toxicity may have been due to structural alterations.

Bacillus thuringiensis↗
PubMed1991

The association of oral contraception with kidney cancer, colon cancer, gallbladder cancer (including extrahepatic bile duct cancer) and pituitary tumours.

This paper reviews the evidence for a relationship between oral contraceptive use and certain neoplasms: cancers of the kidney, colon and gallbladder (including the extrahepatic bile ducts) and tumours (benign or malignant) of the pituitary. Special reference is made to controlled epidemiological studies, both case-control and cohort. There is no convincing evidence that oral contraceptive use is causally related, either negatively or positively, to any of the tumours studied.

Bile Duct Neoplasms↗
PubMed1991

Dynamics of swaying of Picea sitchensis.

Six 26-year-old Sitka spruce (Picea sitchensis (Bong.) Carr.) trees growing in a Scottish plantation were swayed manually to determine their mechanical dynamics. The natural frequency of sway of the intact trees (mean height 14.2 m and mean stem diameter 14.5 cm at 1.3 m) was on average 0.35 Hz. The variation of this frequency with tree size was found to be well described by engineering mechanics theory. In particular, shape parameters could be defined for both intact and branchless trees, which, along with stem size, density and elasticity, could predict the natural sway frequency using a simple formula. The damping of sway was found to consist of three components, (1) interference of branches with those of neighbors, (2) aerodynamic drag on foliage, and (3) damping in the stem. For the sample of six trees, which spanned the diameter range at the experimental site, the importance of these three components to overall damping was in the ratio 5/4/1 for the median sized tree. Interference between neighbors depended on the distance to neighbors, as well as on the sizes of the chosen tree and its neighbors. Aerodynamic damping was larger for larger trees and the energy lost to this force was similar in magnitude to that calculated to be lost using drag coefficients from published wind tunnel and other studies. The amount of damping from the stem was linearly related to stem diameter.

Journal Article↗
PubMed1991

The state of general practice computing in Scotland and the characteristics of computerised practices: a survey of 948 practices.

A survey of 1,179 Scottish practices produced an 81% response rate and gathered data about practice size, environment, state of computerisation as well as future plans for the use of computers in the practice. Results show that the majority of practices are already computerised and that over 90% will be computerised soon. A computer in the practice correlates especially with the presence of a practice manager, a practice nurse and training or teaching status. Scotland is unique in having a national software program (GPASS) for general practice administration. We estimate that by mid 1991 over 750 practices will be using GPASS.

Computers↗
PubMed1989

The use of monoclonal antibodies to localize the low density lipoprotein receptor-binding domain of apolipoprotein B.

Human apolipoprotein (apo) B-100 is composed of 4536 amino acids. It is thought that the binding of apoB to the low density lipoprotein (LDL) receptor involves an interaction between basic amino acids of the ligand and acidic residues of the receptor. Three alternative models have been proposed to describe this interaction: 1) a single region of apoB is involved in receptor binding; 2) groups of basic amino acids from throughout the apoB primary structure act in concert in apoB receptor binding; and 3) apoB contains multiple independent binding regions. We have found that monoclonal antibodies (Mabs) specific for a region that spans a thrombin cleavage site at apoB residue 3249 (T2/T3 junction) totally blocked LDL binding to the LDL receptor. Mabs specific for epitopes outside this region had either no or partial ability to block LDL binding. In order to define the region of apoB directly involved in the interaction with the LDL receptor we have tested 22 different Mabs for their ability to bind to LDL already fixed to the receptor. A Mab specific for an epitope situated between residues 2835 and 2922 could bind to its epitope on LDL fixed to its receptor whereas a second epitope between residues 2980 and 3084 is inaccessible on receptor-bound LDL. A series of epitopes near residue 3500 of apoB is totally inaccessible, and another situated between residues 4027 and 4081 is poorly accessible on receptor-bound LDL. In contrast, an epitope that is situated between residues 4154 and 4189 is fully exposed. Mabs specific for epitopes upstream and downstream of the region 3000-4000 can bind to receptor-bound LDL with a stoichiometry close to unity. Our results strongly suggest that the unique region of apoB directly involved in the LDL-receptor interaction is that of the T2/T3 junction.

Antibodies, Monoclonal↗