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Biomedical subjects

D G Ferguson

Publications and source records attributed to D G Ferguson.

At least 55 records · Page 3Linked to original sources
PubMed1988

Discrimination between fast- and slow-twitch fibres of guinea pig skeletal muscle using the relative surface density of junctional transverse tubule membrane.

The black reaction of Golgi was used to infiltrate transverse (T) tubules in fast-twitch glycolytic (FW), fast-twitch oxidative-glycolytic (FR) and slow-twitch (S) type fibres in muscles of guinea pigs. Non-junctional (fT) and junctional (jT) segments of the T-tubule network are clearly demarcated by this technique. Digitized planimetry and direct measurements were used to determine the proportion of T-tubule network forming junctions with the sarcoplasmic reticulum (%LjT) and to estimate the surface density (surface area per fibre volume) of total and junctional T membrane. From these data, the volume density (number per fibre volume) of junctional feet was calculated. All three types of fibres have approximately equal surface density of T tubules, but the FW and FR fibres have a much higher proportion of jT. The calculated volume density of feet is twice as high in fast-twitch as in slow-twitch fibres.

Animals↗
PubMed1988

Mallet finger: a trial of two splints.

Over a period of twelve months, 116 cases of mallet finger were allocated randomly to treatment with either a Stack or Abouna splint. The two splints were equally effective, producing a cure or a significant improvement in approximately 50% of cases. However, the Stack splint was much preferred by the patients, who found it more comfortable, more robust and easier to keep clean.

Adult↗
PubMed1988

Mallet finger: comparison between operative and conservative management in those cases failing to be cured by splintage.

Sixty-nine patients with mallet finger who failed to be cured by a period of splintage were offered either tenodermodesis or Kirschner wire fixation of the DIP joint. Eleven (16%) accepted the offer and eight of these were significantly improved. Of those patients declining surgery, 30 were available for review after a minimum period of six months; of these 13 (43%) had undergone a significant spontaneous improvement.

Bone Wires↗
PubMed1988

Localization of phospholamban in smooth muscle using immunogold electron microscopy.

Phospholamban, the putative regulator of the Ca2+-ATPase in cardiac sarcoplasmic reticulum, was immunolocalized in canine visceral and vascular smooth muscle. Gently disrupted tissues were labeled with an affinity-purified phospholamban polyclonal antibody and indirect immunogold, using preembedding techniques. The sarcoplasmic reticulum of smooth muscle cells was specifically labeled with patches of immunogold distributed in a nonuniform fashion, while the sarcolemma did not appear to contain any phospholamban. The outer nuclear envelopes were also observed to be heavily labeled with the affinity-purified phospholamban polyclonal antibody. These findings suggest that phospholamban may play a role in the regulation of cytoplasmic and intranuclear calcium levels in smooth muscle cells.

Animals↗
PubMed1987

Acute management of the self-cutter.

'Self-cutting' is a specific type of emergency presenting to accident and emergency departments. All cases presenting in Sheffield in a 6-month period were studied. The self-cutter is most often a young, unemployed man: this is the group most likely to cut repeatedly. At least 45% of all cutters had a past psychiatric history, and a quarter of them were judged a high suicidal risk. The seriousness of the physical injury and the suicidal risk cannot be simply correlated. The crucial part of acute management is the decision about psychiatric referral. As with a complex physical injury, formal assessment must be performed and specialist referral made on that basis.

Adult↗
PubMed1986

A computerized prospective audit of cardiopulmonary resuscitation in the accident and emergency department.

A prospective survey of cardiopulmonary resuscitation is in progress in the Accident and Emergency Department of the Royal Hallamshire Hospital. During the 12 months from January 1985 to January 1986, 123 cardiac arrests were treated in the accident department. Ninety of these arrests occurred outside the hospital; nine of these patients survived to leave hospital. Of the 33 people arresting in the department, 10 survived to leave hospital. The causes of death are presented.

Emergency Service, Hospital↗
PubMed1985

Ordered arrays of Ca2+-ATPase on the cytoplasmic surface of isolated sarcoplasmic reticulum.

Isolated sarcoplasmic reticulum (SR) vesicles with polymerized calcium pump protein were freeze-dried and rotary shadowed following uranyl acetate stabilization. This technique allows direct observation of a single side of the vesicle without requiring optical filtering. The heads of individual ATPase molecules, projecting above the cytoplasmic surface, are clearly resolved in the replicas. Ca ATPase molecules form extensive arrays in vanadate-treated, rabbit SR vesicles and in gently isolated, native SR vesicles from scallop. Gentle isolation results in limited areas of orderly structure in native SR isolated from vertebrate muscles. Special attention is given to the effect of various shadow thicknesses on the appearance of the heads. This information is essential to the interpretation of images in the accompanying paper (Franzini-Armstrong, C., and D.J. Ferguson, 1985, Biophys. J., 48:607-615).

Acetates↗
PubMed1985

Density and disposition of Ca2+-ATPase in sarcoplasmic reticulum membrane as determined by shadowing techniques.

We have studied the disposition of calcium ATPase in the native sarcoplasmic reticulum (SR) membrane of vertebrate muscles by rotary shadowing of freeze-dried isolated vesicles and of freeze-fractured in situ membranes. The predominant disposition of the ATPase molecules is disorderly, but small oligomers (dimers, tetramers, and occasionally larger aggregates) are seen. In vesicles from white hind legs of rabbits, the density of ATPase over nonjunctional SR is 31-34,000/microns2. ATPase density is always quite high, but small protein-free lipid patches may be interspersed with it.

Animals↗
PubMed1984

Subunit structure of junctional feet in triads of skeletal muscle: a freeze-drying, rotary-shadowing study.

Isolated heavy sarcoplasmic reticulum vesicles retain junctional specializations (feet) on their outer surface. We have obtained en face three-dimensional views of the feet by shadowing and replicating the surfaces of freeze-dried isolated vesicles. Feet are clearly visible as large structures located on raised platforms. New details of foot structure include a four subunit structure and the fact that adjacent feet do not abut directly corner to corner but are offset by half a subunit. Feet aligned within rows were observed to be rotated at a slight angle off the long axis of the row creating a center-to-center spacing (32.5 nm) slightly less than the average diagonal of the feet (35.3 nm). Comparison with previous information from thin sections and freeze-fracture showed that this approach to the study of membranes faithfully preserves structure and allows better visualization of surface details than either thin-sectioning or negative-staining.

Animals↗
PubMed1984

Why do accident and emergency doctors request X-rays?

A prospective study was carried out to analyse all X-rays requested from the three accident and emergency departments in Sheffield during one week. There were 3253 patients examined, of which 1028 (31.6%) were X-rayed, 1251 sets of X-rays being performed. Few X-rays (4.5%) were requested for medico-legal reasons. Skull X-rays were studied in particular detail. Only 5 (4.5%) of 112 films were subsequently reported as abnormal by the radiologist. The accident and emergency doctor's ability to predict X-ray outcome was not very good, their false positive rate being high at 21% while their false negative rate was low at 5.5%. This indicates that the accident and emergency doctors tended to be over cautious to compensate for their lack of experience.

Emergency Medicine↗
PubMed1983

Effects of thioridazine on the intellectual performance of mentally retarded drug responders and nonresponders.

Forty mentally retarded adolescents were divided into two divisions on the basis of prestudy assessments that identified subjects as thioridazine hydrochloride responders or nonresponders. Within each division, the participants were assigned randomly to one of four groups. Members of each group received three administrations of the Leiter international performance scale. Four conditions were examined: testing under standard conditions and testing under reinforcement conditions while receiving and not receiving thioridazine. Condition sequences were random in all four groups. Assessments were double-blind and placebo controlled. The results showed that while both drug responders and nonresponders were receiving thioridazine there were no major differences in test scores obtained under standard and reinforcement conditions. While subjects were not receiving thioridazine there were considerable increases in scores obtained under the reinforcement conditions.

Adolescent↗
PubMed1983

Postnatal development of sarcolemmal invaginations in right atrial myocardium of the rat.

Postnatal development of the sarcolemmal invaginations of right atrial cells of the rat has been studied using standard fixation combined with tannic acid mordanting. T tubules were seen to form at Z lines as simple tubular invaginations starting at the 14th postnatal day. T tubules were present in most cells by the 18th postnatal day but, as in the adult, were restricted to peripheral regions. Also, between the 16th and 18th postnatal day a proliferation of caveolae was seen, both as single vesicles and as complexes with up to a dozen caveolae sharing the same neck. The caveolar complexes persisted in the adult and did not seem to contribute significantly to the formation of the T tubules. Dyadic couplings were seen to become more abundant as T tubules and caveolae proliferated. These findings are discussed in relation to transsarcolemmal Ca2+ movements and excitation-contraction coupling during postnatal development.

Animals↗
PubMed1982

Effects of thioridazine and withdrawal dyskinesias on workshop performance of mentally retarded young adults.

The authors conducted a two-part study of the effects of thioridazine and withdrawal dyskinesias on the workshop performance of mentally retarded young adults. In part 1, 80 mentally retarded subjects were divided into five groups of 16 according to administration, discontinuation, or nonadministration of thioridazine. The major finding was that thioridazine can impair the workshop performance of mentally retarded individuals. In part 2, 28 subjects were divided into four matched groups of 7 subjects each whose thioridazine dose was abruptly or gradually discontinued and who did or did not have withdrawal dyskinesias. Workshop performance declined with the onset of the dyskinesias and improved as the dyskinesias subsided.

Adolescent↗