Biomedical subjects
Publications and source records attributed to D G Jones.
The authors present the case of a young woman who sustained ipsilateral scaphoid and Colles' fractures that were treated by a combination of Herbert screw fixation of the scaphoid fracture and external fixation of the colles' fracture. This form of treatment provides optimal conditions for both the early return of wrist function and for the maintenance of the manipulated position.
As skull and cervical spinal radiographs are being obtained routinely on head and neck injuries, more incidental anomalies of the neck region are being detected. The differentiation of congenital anomaly from fracture can be difficult. The importance of this, however, cannot be underestimated because of the dire consequences of a missed cervical fracture. A case of such an anomaly and its presentation following injury is presented.
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A collaborative survey between the National Radiological Protection Board and the Hospital Physicists' Association has been conducted to ascertain current levels of exposure for patients undergoing 10 routine types of X-ray examination in England. The main part of this study consisted of measurements on nearly 3200 patients attending 20 randomly selected English hospitals. The energy imparted to each patient was determined from a measurement of the total exposure-area product for the examination. In addition, thermoluminescent dosemeters were attached to the patient's skin to enable the derivation of doses to the major radiosensitive organs, either directly or using appropriate conversion factors calculated for a mathematical phantom by a Monte Carlo technique. Histograms are presented showing the wide distributions often observed in the doses for each type of examination. Mean values of exposure-area product, energy imparted to the patient, entrance skin dose per film and organ dose are reported, together with coefficients of variation. Comparison of the results with those from similar surveys in the UK and abroad is complicated by inconsistencies in the reporting of such data, but substantial differences are sometimes apparent, particularly for the estimates of organ doses. The present measurements will provide a useful baseline for future measurements and will be used to evaluate the collective dose to the population from medical exposures and the radiation risks from the various radiological procedures.
Partridge bands have been developed and marketed on the assumption that their ribbed under-surface would ensure less interference with periosteal and cortical blood flow than other cerclage systems. Three cases are reported of serious clinical complications from loss of cortical bone under the band, and interference with the external bridging callus response.
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The postnatal development of the superficial (optic) layers of the rat superior colliculus has been studied using Klüver-Barrera staining and Golgi impregnation in rats aged 3-45 days. The Klüver-Barrera staining reveals that the SC of 3 day old rats is morphologically immature with no obvious lamination. It contains densely packed cells of uniform size. The packing density of the cells gradually decreases between 9 and 15 days as the thickness of the layers increases. The first myelinated fibres in the SC appear at 15 days but the stratum opticum is still not recognizable. By 30 days, the SC has a distinctly laminated appearance, but the thickness of the superficial layers continues to increase until day 45 postnatal. Golgi-Cox impregnation displays the range of neuronal types in the superficial layers of the SC previously described by Langer and Lund (1974). Using the morphological criteria of these authors for classification of the neurons, the developmental changes of the marginal cells, horizontal cells, ganglion cells types I, II, III and stellate cells have been followed. The SC of 3 day old rats contains immature neurons; only a few larger cells have branched dendrites. In 9 days old SC the neuronal types present in the adult are recognizable, although their appearances are still immature. By 15 days neurons have adult-looking dendritic trees but dendritic growth continues beyond 30 days. The visual part of the SC has a protracted period of postnatal development, the sequence of developmental changes being similar for the different types of collicular neurons. Features common to development are the increasing size of neuronal somata, the increasing length of dendrites and the acquisition of a complex pattern of dendritic arborization. Larger cells appear to commence development earlier than small cells, although the rate of developmental changes is different for each of the various types of collicular neurons.
Two patients are described with the Schwartz-Bartter syndrome (Bartter and Schwartz, 1967; Barter, 1973). The first followed concussion, the second followed a chest injury with accompanying minor head injury. The clinical features and treatment of this condition are briefly discussed. Awareness of this potentially serious complication of injury enables early and effective treatment.
Male rats were exposed daily to ethanol vapour from 3 days of age, and their brains were examined at 7, 14, 21, 56 and 76 days postnatally. Control animals were examined at each age, and ethanol-rehabilitated animals were examined at 56 and 76 days postnatally. Tissue from the parietal cortex of each animal stained with osmium tetroxide and with ethanolic-phosphotungstic acid (E-PTA) was analyzed by qualitative ultrastructural techniques. The ethanol flow rate in the incubation chamber was adjusted to maintain the blood ethanol level as close as possible to 0.1 g/100 ml. Ethanol-treated rats weighed less than ethanol-rehabilitated animals at days 56 and 76. At day 7 synapses were formed between axons and dendritic growth cones, dendritic shafts and filopodia in control and ethanol-treated tissue. At days 14 and 21 well-developed axodendritic and axospinous synapses were evident in both groups. The neuropil of 56- and 76-day-old material was similar in the control and treatment groups, except that there was an enlargement of dendritic profiles in the 56-day-old ethanol-treated material. Perforated synapses were most common in 56-day-old ethanol-treated material, with degenerating synapses most common in 56-day-old (and to a lesser extent 76-day-old) ethanol-rehabilitated material. No obvious differences were detected between any of the groups of the E-PTA-stained material. The presence of degenerating and perforated synapses suggests that synaptic remodelling is occurring, and this may be a means of adapting synaptic mechanisms to the functional demands imposed by ethanol.
Male rats were exposed to ethanol vapour daily from 3 days of age, and their brains were examined at 7, 14, 21, 56 and 76 days postnatally. Control animals were examined at each age, with ethanol-rehabilitated animals being examined at 56 and 76 postnatal days. Tissue, stained with osmium tetroxide and with ethanolic-phosphotungstic acid, from the parietal cortex of each animal was analyzed by quantitative ultrastructural techniques. Most of the statistically significant findings occurred at days 56 and 76. When compared with controls, ethanol-treated material at 56 days was characterized by a decrease in the number of synapses which were larger and more spherical, with a greater number of synaptic vesicles and a decrease in dense projections. At 76 days there was an increase in the percentage of axospinous-symmetrical terminals in the ethanol-treated population. In ethanol-rehabilitated tissue at 56 days the synaptic terminals were relatively immature, and were smaller, with a reduced number of synaptic vesicles coupled with an increase in large cisternae and with more positively curved junctions. By 76 days this material was practically indistinguishable from control tissue. It is proposed that at 56 days of age synaptic remodelling is under way in the ethanol-treated material, whereas following rehabilitation the terminals are relatively immature and appear to be actively functioning. Low to moderate levels of ethanol administered postnatally have a limited effect on synaptic maturation.
The stability and storage characteristics were studied of 11 bovine enzymes of potential clinical significance, namely, aldolase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, acetylcholinesterase, creatine kinase, gamma glutamyltransferase, glutathione peroxidase (GSH-Px), alpha-hydroxybutyrate dehydrogenase, lactate dehydrogenase and superoxide dismutase (SOD). Enzyme activities in fresh serum were compared with those in plasma containing various anticoagulants including lithium heparin, EDTA and oxalate/fluoride. The same preservatives were assessed for their effects on the whole blood activities of GSH-Px and SOD. Stabilities of enzymes in plasma and serum stored at room (+20 degrees C), refrigerator (4 degrees C) or deep freeze (-20 degrees C) temperatures were also compared. In addition, SOD and GSH-Px activities in samples stored, at the same temperatures, as whole blood or aqueous lysates were monitored.
The stability and storage characteristics were studied of 11 ovine enzymes of potential clinical significance, namely, aldolase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, acetylcholinesterase, creatine kinase, gamma glutamyltransferase, glutathione peroxidase (GSH-Px), alpha-hydroxybutyrate dehydrogenase, lactate dehydrogenase and superoxide dismutase (SOD). Enzyme activities in fresh serum were compared with those in plasma containing various anticoagulants including lithium heparin, EDTA and oxalate/fluoride. The same preservatives were assessed for their effects on the whole blood activities of GSH-Px and SOD. Stabilities of enzymes in plasma and serum stored at room (+20 degrees C), refrigerator (4 degrees C) or deep freeze (-20 degrees C) temperatures were also compared. In addition, SOD and GSH-Px activities in samples stored, at the same temperatures, as whole blood or aqueous lysates were monitored. The results are discussed with particular reference to the differences between sheep and cattle.
An enzymatic 'reaction rate' micro-method for the rapid routine estimation of D-B-hydroxybutyrate (D-B- HOB ) in ruminant plasma, using an I.L. Multistat III centrifugal analyzer, is described. Reaction conditions were optimized to give a linear response for plasma D-B- HOB concentrations between 100 and 2500 mumoles per litre, at 30 degrees C and pH 9.0. For the standardized method the within-run and between-run coefficients of variation for deproteinised ovine plasma were consistently less than 3.5%. There was good agreement between plasma concentrations obtained by the present method and both original U.V. end-point technique (r = 0. 927b = 0.950) and a colorimetric end-point procedure (r = 0.937. b = 0.879). Untreated ovine and bovine plasma consistently exhibited high 'blank' activity and this was directly correlated with plasma lactate dehydrogenase (LDH) activity in both species (r = 0.971; p less than 0.001 and r = 0.949; p less than 0.001 respectively). The distribution of LDH activity in man was similar to sheep but, contrastingly , non-specific interference was extremely low in human plasma and unrelated to LDH. Horse, chicken and rat had negligible 'blank' activity and comparatively low LDH levels. In both cattle and sheep non-specific interference was abolished by perchloric acid precipitation. In the sheep subtraction of 'blank' activity gave D-B- HOB concentrations for untreated plasma comparable to those in deproteinised samples. However, in the bovine, D-B- HOB levels remained significantly (t = 6.44; p less than 0.001) higher even after 'blank' correction. In contrast to man and other non-ruminants, perchloric acid precipitation is essential in ruminants to avoid false overestimation of plasma D-B- HOB levels. Plasma with EDTA as anticoagulant and serum gave concentrations of D-B- HOB approximately 60% lower, than samples containing heparin or oxalate/fluoride. However, heparin was associated with much higher (up to 50%) non-specific NAD reduction than oxalate/fluoride. High levels of acetoacetate (400-1000 mumoles per litre) reduced the recovery of D-B- HOB from ovine plasma by less than 10%. This effect was negated by the inclusion of hydrazine hydrate in the reaction mixture. Perchlorate ion concentrations above 25 mumoles per litre per test dramatically inhibited the assay in ovine plasma, and therefore precipitation conditions must be carefully controlled. Plasma with oxalate/fluoride as anticoagulant showed the greatest stability in storage; 24 hours at room temperature, one week at +4 degrees C and at least one month at -20 degrees C.
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Presumptive neurons, immature neurons and degenerating structures were found in the intermediate and deep layers of the superior colliculus of normal cats over the age range 7-45 days postnatal. Electron microscopical analysis revealed these structures to be unexpectedly frequent in the early postnatal period. There were 34 immature neurons per 1000 neurons at 7-8 days and 78 per 1000 neurons at 14 days postnatal. Few were found in older cats. Two types of degenerative changes in the neurons were observed: nuclear and cytoplasmic. The number of degenerating structures to be unexpectedly frequent in the early postnatal period. There were 34 immature neurons per 1000 neurons at 7-8 days and 78 per 1000 neurons at 14 days postnatal. Few were found in older cats. Two types of degenerative changes in the neurons were observed: nuclear and cytoplasmic. The number of degenerating neurons was higher at 14 days (28 per 1000 neurons) than at 7-8 days (21 per 1000 neurons), but only a few were found at 30 and 45 days. Degenerative changes were noted in synaptic terminals at all ages studied. The greatest number of degenerating synaptic profiles were observed at 14 and 30 days. They were infrequent in younger or older animals. The number of presumptive neurons does not change significantly over 7-14 days. It is speculated that they persist as a reverse pool of neurons. The increasing number of immature neurons in the period between 7 and 14 days indicates that formation of new cells in the intermediate and deep layers of the superior colliculus continues into the early postnatal period. The degeneration of some neurons and synapses over the same developmental period suggest that the final adjustment of the neuronal composition of the superior colliculus occurs postnatally.
Morphological variation of the synaptic active zone during later development and maturation (15-224 days) has been studied in the molecular layer of the rat occipital cortex. Both E-PTA stained and osmicated tissue have been used. In the E-PTA stained material the degree of specialization of the presynaptic thickening is directly related to junction length. Junctions with well-developed dense projections (Types A and B) are longest and continue to increase in length with maturation, suggesting that active remodelling of the synaptic apposition is an ongoing process. The presence of perforated junctions, possessing two or more regions with specializations of different maturity and different curvature, raises the possibility that these junctions may arise by the addition and differentiation of new paramembranous material at an existing junction. In osmicated tissue, presynaptic terminals possessing multiple active zones have been quantitated. The maturational increase in number of simple perforated junctions (Type 1), is paralleled by a smaller increase in the number of multiple perforated junctions (Type 2). A spine apparatus is frequently observed in these perforated terminals, suggesting that it is intimately involved in the reorganization. The direction of curvature of the closely apposed junctions is predominantly negative (indenting the postsynaptic process). Other types of arrangement, with separate postsynaptic processes, are described (Types 3-5), and micrographs suggestive of sequential stages in pre- and postsynaptic terminal splitting are presented. The total length of the postsynaptic thickening of perforated terminals is twice the mean synaptic length of non-perforated terminals, again suggestive that duplication of the active zone may have occurred. Division of existing synaptic terminals by duplication and subsequent splitting would readily account for the increased dendritic spinal numbers seen in Golgi preparations of animals raised under enriched conditions. This would be a straight-forward mechanism by which reinforcement of neuronal connections could occur in response to use.
The mean energy imparted to the patient has been proposed as a practical quantity which may be useful for assessing somatic risk in X-ray diagnostic radiology. A technique is described for estimating energy imparted during most common X-ray examinations of the trunk or complete head from a measurement of exposure-area product conveniently provided by the Diamentor transmission ionisation chamber. The necessary energy imparted calibration for the Diamentor has been deduced from consideration of incident spectral energy fluence and Monte Carlo calculations of the fraction of total beam energy imparted to mathematical phantoms representing the patient. The relationship between energy imparted and exposure-area product depends primarily on the applied potential and total filtration of the X-ray beam, and to a lesser extent on voltage waveform and X-ray target angle. Direct measurements of energy imparted to an Alderson Rando phantom for a range of irradiation conditions provided an excellent verification of the technique developed. Using the energy imparted per exposure-area product factors presented, overall uncertainties of less than +/- 15% and +/- 20% should be possible for measurements of energy imparted during examinations of the trunk and head respectively using the Diamentor.