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Biomedical subjects

A Howe

Publications and source records attributed to A Howe.

At least 19 recordsLinked to original sources
PubMed1992

Effect of zinc ions on the biochemical behavior of simian virus 40 small-t antigen expressed in bacteria.

The simian virus 40 small-t antigen contains 10 cysteine residues, 6 of which are organized in two CysXCysXXCys clusters. Mutation of individual Cys residues in the two clusters or mutation of specific residues found between these clusters causes pronounced instability of the protein in animal cells. Protein instability correlates with failure of the bacterially expressed mutant proteins to bind zinc ions, an interaction which allows purification of large amounts of small-t antigen in monomeric form.

Amino Acid Sequence↗
PubMed1992

Gait analysis in ankylosing spondylitis.

A study was conducted to compare the gait pattern of 12 patients with ankylosing spondylitis with axial disease only with that of 11 healthy controls using a telemeterised electrogoniometer gait analysis system. The reproducibility of the gait variables was found to be acceptable. Angles for movement at the hip and knee were less in patients with ankylosing spondylitis, but hip/knee angle ratios did not differ between the two groups. The stride length was shorter in the patients with ankylosing spondylitis. These findings are due to the increased rigidity of the spine, which results in decreased shock absorption and consequently a more cautious gait pattern in the absence of clinically and radiologically detectable peripheral joint disease.

Adult↗
PubMed1990

Studies of the morphology and structure of the plasma lipid transfer particle from the tobacco hornworm, Manduca sexta.

Morphological features of Manduca sexta plasma lipid transfer particle (LTP) have been investigated by electron microscopy. LTP was found to be an asymmetric particle with two major structural features: a roughly spherical head and an elongated, hinged tail. The hinge occurs approximately at the midpoint of the tail section with the two halves forming angles ranging from 30 degrees to 180 degrees. A molecular mass estimate of 1.4 x 10(6) daltons based on the dimensions of LTP suggests that multiple copies (two or three) of each of the three LTP apoproteins exist in the native complex. Limited digestion studies of LTP suggest that apoLTP-III is less susceptible to trypsin cleavage than apoLTP-I or -II, and therefore may be less exposed to the aqueous environment. Digestion for 1 h at a 1:50 trypsin-LTP protein ratio did not alter the flotation properties of LTP or its morphological features; thus, although significant proteolysis occurred, the particle retained its overall structure. Transfer activity, on the other hand, was affected by trypsin digestion with 30 +/- 14% inhibition of LTP activity occurring upon proteolysis at a 1:50 trypsin-LTP protein ratio. Treatment of LTP with phospholipase A2 resulted in the conversion of LTP-associated phosphatidylcholine and phosphatidylethanolamine to their corresponding lyso forms. Phospholipase A2 treatment did not, however, alter the SDS-PAGE profile, transfer activity, flotation pattern, or the microscopic features of LTP. These results suggest that the products of the phospholipase reaction remain associated with the particle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Noradrenaline turnover in brown adipose tissue and the heart of fed and fasted golden hamsters.

The effect of fasting on sympathetic activity in tissues of the golden hamster has been investigated using measurements of noradrenaline turnover. Fasting for 60 h did not have a significant effect on noradrenaline turnover, both fractional and total, in brown adipose tissue or the heart. Fasting did, however, result in a functional atrophy of brown adipose tissue; tissue weight, protein content, and cytochrome oxidase activity were each reduced after a 60-h fast. These results suggest that the atrophy of brown adipose tissue induced by fasting in the golden hamster does not relate to a major decrease in sympathetic activity. The findings add further support for the view that the thermogenic capacity of brown adipose tissue is not primarily dependent on sympathetic activity in the golden hamster.

Adipose Tissue, Brown↗
PubMed1988

An evaluation of the dynamic qualities of isometric grip strength.

A strain gauged torsion dynamometer linked to a microprocessor was used to assess the dynamic qualities of isometric grip strength in patients with rheumatic diseases. Maximum grip strength, time to maximum grip, and percentage fatigue provide independent information on the grip. Time to maximum grip does not appear to be an objective correlate of subjective stiffness. The usefulness of these dynamic variables for the assessment of stiffness appears limited in arthritic disease, where pain may interfere with the maximum voluntary effort of the test.

Arthroplasty↗
PubMed1988

Lack of objective evidence of stiffness in rheumatoid arthritis.

Metacarpophalangeal joint stiffness was measured using a new microprocessor controlled arthrograph in 135 patients with rheumatoid arthritis. Subjects were prospectively subdivided according to the stage of the disease in the joint. Compared with a normal population stiffness variables in active rheumatoid arthritis were decreased, significantly so for non-elastic stiffness. This study casts doubts on the literal interpretation of symptomatic stiffness as an indicator of disease activity in rheumatoid arthritis and suggests a number of explanations for the discordant result.

Arthritis, Rheumatoid↗
PubMed1987

Functional assessment of the hand: reproducibility, acceptability, and utility of a new system for measuring strength.

A new system for measuring strength of the hand using a torsion dynamometer linked to a microprocessor is described. The system permits analysis of timed squeezes of both grip and pinch and is adjustable to all sizes of hand and degrees of hand deformity. Results obtained with the system were found to be reproducible, and the rigid device was acceptable to a group of patients with arthritic hands. In rheumatoid arthritis there is a marked reduction in maximum grip and pinch strength, together with a prolongation of the time taken to reach this maximum, and increased fatigue. The limitations of grip strength as a measure of function of the hand are discussed.

Adult↗
PubMed1986

The effect of hypoxia on the number of amine-containing cells in the lung of the adult rat.

Adult rats of Wistar and Sprague Dawley strains were exposed to a 21-day period of hypoxia (10% O2). At the end of this period, the hypoxic animals and paired controls were anaesthetised, dissected and tissues were taken for light microscopy. All the hypoxic animals had an increased haematocrit, right ventricle weight and carotid body size when compared with controls. The Grimelius method was used to demonstrate argyrophil structures in the lung. This method stained the amine-containing cells of the epithelium, mast cells and nerves. Mast cells associated with the pulmonary vasculature were increased in number in the hypoxic animals. Single epithelial argyrophil cells were more frequent than those in groups. In control animals the groups of cells only rarely contained more than 5 cells. In the Wistar strain there was no significant difference in the number of argyrophil cells between the control animals and those exposed to chronic hypoxia. However, in the Sprague Dawley rats, the numbers of cells, both single and in groups, were significantly increased following 3 weeks chronic hypoxia. The cell groups were also larger in the hypoxic animals, with up to 12 cells per section.

APUD Cells↗
PubMed1985

Antidiuretic hormone involvement in the release of alpha-melanocyte-stimulating hormone by hyperosmotic stimuli.

In the normal Wistar rat, the plasma alpha-MSH level was raised by hypertonic saline injection (as compared with control rats injected with isotonic saline). No such rise in alpha-MSH followed hypertonic saline administration in the Brattleboro (hereditary diabetes insipidus) animal (compared to isotonic saline injected controls). It is suggested that, in the rat, endogenous antidiuretic hormone is involved in the secretory response of the pars intermedia to osmotic stimuli.

Animals↗
PubMed1985

Microprocessor controlled arthrograph.

This new arthrograph, based on a microcomputer, provides displacements of variable amplitude, frequency and waveform. It is sufficiently small for use on a ward or in a clinic, is simple to use and is readily accepted by patients. One test and its associated analysis, together with printed and plotted results, occupies little more than two minutes.

Arthritis, Rheumatoid↗
PubMed1985

Reference values for metacarpophalangeal joint stiffness in normals.

A new form of microprocessor-controlled arthrograph is described which measures stiffness parameters of the metacarpophalangeal joints of the index, middle, and ring fingers of both hands. The apparatus is simple and quick to use and gives reproducible results. The arthrograph is used to determine the reference limits for stiffness at the middle finger of the right hand in 128 normal subjects. It is found that incorporating information on the subject's finger circumference allows a much improved precision to be achieved, but the precision is not further enhanced by including details of age and sex.

Adolescent↗