Biomedical subjects
B J Smith
Publications and source records attributed to B J Smith.
SDS polyacrylamide gel electrophoresis of proteins.
Explore the source record for details and available documents.
Enzymatic methods for cleaving proteins.
Explore the source record for details and available documents.
Acetic acid-urea polyacrylamide gel electrophoresis of proteins.
Explore the source record for details and available documents.
Chemical modification of tissue inhibitor of metalloproteinases-1 and its inactivation by diethyl pyrocarbonate.
Tissue inhibitor of metalloproteinases-1 (TIMP-1) was treated with a range of chemical modification reagents in order to identify amino acid residues essential for inhibitory activity. Diethyl pyrocarbonate (DEPC) was found to be a potent inactivator at low reagent/TIMP molar concentrations. The extent of modification at 50% inactivation was determined as 1.5 sites/molecule. The DEPC-modified inhibitor did not form stable complexes with stromelysin, but was shown to retain native structure as judged by conformational stability to denaturation by guanidine hydrochloride. Peptide mapping experiments were used to find the sites of DEPC incorporation within the primary structure of TIMP and three residues were identified (His-95, His-144 and His-164). Mutant TIMPs in which histidine residues have been substituted or deleted retain inhibitory activity and were found to be equally as sensitive to DEPC inactivation as the wild-type. No new sites of DEPC modification in the mutant proteins were detected. The possible contribution made by His residues 95, 144 and 164 to the inhibitory activity of TIMP is discussed.
Structural analysis of tissue inhibitor of metalloproteinases-1 (TIMP-1) by tryptic peptide mapping.
Tryptic digests of recombinant TIMP-1 have been resolved on reverse-phase HPLC and the major peaks identified by N-terminal sequencing. This procedure accounted for the entire molecule, except two short peptides of 2 and 4 amino acids in length. The peptide map was used to (i), characterize an insoluble 'core' peptide seen on digestion of TIMP-1 in non-reducing conditions; (ii), confirm the structure of delta 127-184TIMP-1, a recently described truncated form of the TIMP-1 molecule; (iii), identify exposed regions of the intact and truncated TIMP-1 molecules by measuring the rate of tryptic peptide release and (iv), locate sites of aberrant proteolysis seen when recombinant human TIMP-1 was purified at large scale.
Awareness of the National Asthma Campaign.
Explore the source record for details and available documents.
Leptospiral abortion and leptospiruria in horses from the same farm.
Leptospirosis was documented as the cause of abortion in a 5-year-old mare. Leptospires were detected in tissue specimens from fetal kidneys and from placenta by histologic evaluation of silver-stained sections. Antibodies against Leptospira interrogans serovar pomona were detected in fetal serum at a titer of 1,600 by use of a microscopic agglutination test. The mare had serum titers of 6,400; 0; 400; 800; 3,200; and 6,400 to L interrogans serovars bratislava, canicola, grippotyphosa, hardjo, icterohaemorrhagiae, and pomona, respectively. A serologic survey identified titers of at least 6,400 against serovars bratislava and pomona in 5 other horses on the farm. Titers of at least 100 against serovar bratislava were detected in 53% of the horses on the farm. Leptospires were detected by direct fluorescent-antibody testing in urine samples from the mare that aborted and from 2 of the other 5 horses.
On the role of the C-terminus of alpha-calcitonin-gene-related peptide (alpha CGRP). The structure of des-phenylalaninamide37-alpha CGRP and its interaction with the CGRP receptor.
alpha-Calcitonin-gene-related peptide (alpha CGRP) lacking its C-terminal phenylalaninamide residue was found not to bind to its receptor as did full-length (amidated) alpha CGRP. Investigation of the structure of these peptides by c.d. and n.m.r. revealed no significant difference, so it seemed that the effect of deleting the C-terminal phenylalaninamide on the biological activity of alpha CGRP was not by disruption of the peptide's structure. Thus the C-terminal phenylalaninamide is an important factor in this ligand-receptor interaction, and the group itself may interact directly with the receptor.
A phosphodiesterase assay using alumina microcolumns.
Explore the source record for details and available documents.
Midazolam sedation for percutaneous liver biopsy.
Control of patient respiration is needed to safely perform percutaneous liver biopsy (PLB) and may be adversely affected by sedation. The purpose of this study was to evaluate the safety of PLB with intravenous midazolam and to evaluate patient acceptance of PLB with and without sedation. Two hundred seventeen consecutive patients underwent 301 percutaneous liver biopsies. One hundred fifty-one of the biopsies were done after the patients were sedated with intravenous midazolam immediately before the biopsy. The last 61 patients were questioned after the biopsy to evaluate the discomfort of the procedure, their memory of the procedure, and their willingness to undergo another PLB. The major complication rate was similar in the midazolam-treated (0.7%) and untreated (0.7%) groups. The midazolam-treated patients had a numerically lower mean pain score (1.5 +/- 0.4 vs 4.0 +/- 0.7) (mean +/- SEM) (P = 0.07) and significantly lower mean memory score (4.8 +/- 0.7 vs 9.9 +/- 0.1) (P < 0.01) than the untreated patients. The treated and untreated groups had similar mean willingness for repeat PLB scores (9.3 +/- 0.3 vs 9.1 +/- 0.6). We conclude that: (1) there is no increased risk of PLB with midazolam and (2) patients have less memory of the procedure with midazolam.
Drug discrimination by humans compared to nonhumans: current status and future directions.
In drug discrimination (DD) procedures, behavior is differentially reinforced depending on the presence or absence of specific drug stimuli. The DD paradigm has been widely adopted by behavioral pharmacologists because of its specificity of stimulus control, concordance with drug action at cellular levels and its use as a preclinical model of subject-rated effects in humans. With the successful extension of DD to humans, a comparison of human and nonhuman DD will help place each in the context of the other. Twenty-eight studies of DD in humans are reviewed, including studies of amphetamine, opioid, benzodiazepine, caffeine, nicotine, marijuana and ethanol discriminative stimuli. Comparison of procedures between studies in humans and nonhumans reveals a common tradition, except the use of instructions appears to facilitate greatly DD acquisition in humans. Findings were qualitatively similar between humans and nonhumans. Potency relationships were quantitatively similar between humans and most, but not all, other species. Areas of human DD needing additional empirical evaluation include the influence of instructions, the effects of training dose and the effects of antagonists. Additionally, antihistamines, barbiturates, nicotine and marijuana are under-represented in human DD.
Assays of cyclic nucleotides. A review of current techniques.
Cyclic nucleotides are recognized as important second messenger molecules, and many assay formats exist for their quantification. This article critically reviews these different approaches. For measurement of cAMP or cGMP in biological fluids or tissue extracts, immunoassay is effective. For other purposes, such as measurement of cyclic nucleotide phosphodiesterase activity, methods that separate nucleotides from their cyclic counterparts are best, and offer a variety of means of detection.
Histoplasmosis in horses.
Histoplasmosis was diagnosed in nine horses during 1986-1990. The infection with Histoplasma capsulatum caused granulomatous placentitis and abortion in one mare in the 7th month of gestation and three mares in the 10th month. Four newborn foals died from severe granulomatous pneumonia within a few days of birth; and a weanling thoroughbred developed granulomatous pneumonia and lymphadenitis at 5 months of age.
When is air medical service faster than ground transportation?
The purpose of this study was to mathematically define a distance or travel-time interval in which air medical evacuation would benefit the patient more than ground transport. The authors derived mathematical formulas from known variables (ground travel, extrication and rendezvous times) and fixed averages (on-scene time, lift-off time, and speeds) and used those formulas to test actual flights for appropriateness. The formulas were: [formula: see text] where Y = ground travel time; R = rendezvous time; Z = extrication time; D = distance to scene (km); and X = air travel time. The formulas provide a guide to prospectively determine the legitimacy of air medical transport. They can also be used retrospectively as a guide for quality assurance purposes. During this study of 123 consecutive scene flights, helicopter benefitted all the entrapped patients but only one-third of non-entrapped patients. Of 44 flights from areas with known ground times, helicopter transport benefitted 14 of 16 entrapped, five of 16 non-entrapped, but only three of 17 rendezvous.
An additional bone in the carpal region of raptorial birds.
In a series of 4 species of owls and 12 species of diurnal raptors, an additional bone was present bilaterally in the area of the carpus. Designating the bone as an "additional bone of the raptorial carpal region" is suggested pending appropriate embryological studies to determine the origin of the bone. Generally, the bone was present in owls and in diurnal raptors with relatively short, rounded wings, but was absent in species with longer, more tapered wings. The bone lies at the cranial edge of the carpal area near the radial carpal bone, and is fixed to the surrounding skeleton by ligaments. The tendon of the tensor patagium longus muscle has one slip that attaches to the additional bone and another that passes over its craniodorsal surface en route to insertion. Awareness of the occurrence of this bone in some raptors, but not others, is essential in clinical evaluation of wing injuries, as well as in forming a prognosis for the return to soundness, the potential for release, and, therefore, the life of an injured raptor.
Effect of orally administered beclomethasone dipropionate on calcium absorption from the gut in normal subjects.
BACKGROUND: There is evidence that patients with chronic obstructive airways disease and asthma who take inhaled steroids have a low bone density. As most of a drug given from a metered dose inhaler is actually swallowed, the possibility that swallowed beclomethasone dipropionate acts topically in the gut to impair calcium absorption was investigated. Such an effect, if sustained, may be a causative factor of long term bone loss. METHODS: A two week randomised, double blind, placebo controlled, crossover trial was performed in 12 normal volunteers. Subjects were randomly allocated to swallow beclomethasone dipropionate capsules (500 micrograms twice a day) or placebo for one week. The alternate capsule was given throughout the second week. At the end of each week, calcium absorption was assessed by a strontium absorption test. Serum parathyroid hormone, plasma calcium, and plasma phosphate concentrations were determined on the last two days of each week. Twenty four hour urinary calcium, hydroxyproline, and cortisol concentrations were measured for four successive days in each week. RESULTS: All subjects completed the study. There was a 12% reduction in strontium absorption during the beclomethasone dipropionate ingestion week. There was also a 23% reduction in 24 hour urinary cortisol excretion during the same week. CONCLUSIONS: Calcium absorption (measured by a strontium absorption test) was reduced by oral administration of beclomethasone dipropionate for one week. Decreased calcium absorption due to swallowed corticosteroid may contribute to side effects of inhaled steroids and further long term studies are needed.