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Biomedical subjects

D H Gray

Publications and source records attributed to D H Gray.

33 records · Page 2Linked to original sources
PubMed1981

A histochemical study of muscle in club foot.

A histochemical analysis was made of 103 muscle biopsies taken from 62 patients with idiopathic club feet. Any reduction in the diameter of the muscle fibres associated with wasting of the calf muscle was recorded. Histochemical abnormalities existing in these biopsies were revealed by comparison with normal biopsies obtained from the normal legs of 13 children with unilateral deformities. No significant difference was found between the diameter of the muscle fibres taken from normal and affected legs aged under six months. This indicates that wasting of the calf muscle is due to a reduction in the number of fibres rather than their size. The muscle structure was normal excluding denervation and reinnervation. The soleus muscle in patients aged under six months contained 61 per cent Type 1 fibres in the affected legs, compared to 44.3 per cent in normal legs. Similar values were found in the normal and abnormal tibialis posterior muscles, long flexors of the toe and peroneal muscles. The change in composition of the soleus muscle and the reduction in the number of fibres may be caused by a defective neural influence on the development of the limb in club foot.

Adolescent↗
PubMed1980

The incidence of femoral neck fractures in New Zealand.

This study reviews the incidence of femoral neck fractures in New Zealand Maoris and non-Maoris. A comparison made with corresponding overseas studies shows that the New Zealand non-7aori age-sex incidence is one of the highest yet observed. Maori women are shown to have an incidence of hip fracture significantly lower than non-Maori women. These results are discussed in the light of the current debate on the aetiology of femoral neck fractures.

Adolescent↗
PubMed1979

Lanthanide markers in a single sample for nutrient studies in humans.

Multiple Lanthanide markers were used to develop procedures for determinations of intake and apparent utilization of four nutrients using data from fecal analysis and known concentrations of markers in nutrients. Terbium oxide was given as the intake marker. All foods contained the other non-absorbed markers, each marker in direct proportion to the amount of a specific nutrient in each food. Nutrient markers were oxides of samarium, scandium, ytterbium, and europium. Fecal collection and subsequent analysis of nutrients and markers were completed. Fecal marker concentration stabilized 2 days following initiation of the marker regime. Thus, after 3 days, a single grab sample could be utilized to analyze for nutrient utilization. The ratio of nutrient marker proportional to nutrient and intake to nutrient excretion provides the data for the calculation of apparent utilization for as many nutrients as nutrient markers incorporated into the food. When direct and marker methods of determining nutrient intake and apparent utilization were compared, no significant differences were found for gross energy, fat, protein, and calcium.

Adult↗
PubMed1979

The control of bone induction in soft tissues.

The induction of bone at the boundary of parenchymal organs has been studied using acid demineralized rib implants in rabbits. The induction of bone is usually confined to that portion of an implant protruding from such an organ though both scant cartilage induction and the induction of bone within the territory of parenchymal organs were seen on a few occasions. Neonatal splenectomy does not influence the inductive properties of bone matrix in muscle or other soft tissues. The inclusion of composite autografts of liver and acid demineralized bone in muscle results in a reduction in the induction rate. It is postulated that the parenchymal organs exclude osteoprogenitor cells and possibly blood-bone bone-marrow-derived osteoinductor releasing cells by some mechanism that is diffusable, thus preventing the initial inductive event. Composite grafts of matrix and muscle produce bone in these tissue, demonstrating that once bone cell differentiation by induction is initiated bone tissue develops even in spleen, liver and kidney parenchyma.

Aging↗
PubMed1978

The effects of varying oxygen tensions upon bone resorption in vitro.

Calvaria from six-day-old infant mice were grown on a grid culture in a chemically defined medium under varying oxygen tensions. Quantitative isotope studies demonstrated a linear association between bone resorption and oxygen tension in the physiological range. This result was supported by histological, histochemical and vital staining experiments. The clinical finding of osteoporosis in areas of hyperaemia could therefore be attributed to a rise in oxygen tension causing increased bone resorption.

Animals↗
PubMed1976

Excision arthroplasty of the hip.

The results of excision arthroplasty on forty hips in thirty-two patients have been studied by personal review. The mean follow-up was ten years and the results were graded in the Lazansky system. The outcome was fairly predictable, most patients achieving a fair to good result. The patients were satisfied with the operation in unilateral cases as a secondary operation, but it was generally unsatisfactory as a primary procedure or when performed bilaterally. Pain relief was satisfactory, and previously infected hips achieved sound wound and bone healing. Half could walk with no aid or one stick. No correlation could be found between the radiological appearances and the quality of the result.

Adolescent↗
PubMed1976

The effects of hyperoxia upon bone in organ culture.

Hyperoxia has been reported to stimulate both resorption and synthesis of bone in vitro. The effects of increased oxygen tension were re-investigated using calvaria from infant mice maintained in a stationary grid culture system for 48 48 hours with an unsupplemented chemically defined medium. Resting resorption due to osteoclastic activity was demonstrated in the explants in air by Von Kossa staining, histology, and 45 Ca release. Resorption was inhibited by exposure to 95 per cent oxygen or hyperbaric oxygenation at 2 atmospheres pressure. Hyperoxia also depressed new bone formatin by osteoblasts although the production of a new collagen, as measured by the incorporation of 3H-proline, was greater in calvaria cultured in hyperbaric oxygen than in paired explants in 95 per cent oxygen. Thus hyperoxia was toxic for both synthetic and resorptive activity of bone cells; these effects may stem from the loss of vital factors present in natural MEDIA supplements.

Animals↗
PubMed1975

Studies of nutritional safety of some heavy metals in mice.

Heavy metals have been proposed as nutrient markers to allow the accurate determination of the time of passage, nutrient intake, or apparent utilization of multiple nutrients. In order to evaluate possible toxic effects of scandium, chromium, lanthanum, samarium, europium, dysprosium, terbium, thulium, and ytterbium oxides, and barium sulfate upon growth, general development, reproduction, and lactation, mice were fed different levels of these compounds for three generations. The amount of elements fed were 0,110, 100, and 1000 times the use amount. The use amounts were (in ppm2.) : Sc, 0.12; Cr, 0.02; La.0.40;; Sm. 0.80; Eu, 0.036:TB, 1.20; Dy, 1.20; Tm. 0.08; Tb, 0.12; and Ba, 0.008. The use amount was one-fifth of the concentration required for activation analysis. Mortality and morbidity were negligible. No consistent growth rate changes were observed; however, different groups showed different growth rates during different generations. The number of mice born showed no significant differences amoung treatment groups. Survival, growth rate, hematology, morphological development, maturation, reproduction, and lactational performance were comparable in mice fed the different levels of 10 heavy metal oxides to those mice fed the basal diet.

Animals↗
PubMed1975

Observations on the induction of bone in soft tissues.

Using bone decalcified with 0-6 N hydrochloric acid as an inducing agent, the inductive capacity of different soft tissue sites was investigated. Muscle and fascia regularly permitted the induction of bone, while spleen, liver and kidney suppressed bone induction. Bone formation could be induced in these organs if living autologous fascia was implanted together with the inducing agent; while bone formation was inhibited when living autologous spleen tissue was implanted with the inducing agent to normally favourable sites. The administration of systemic heparin and the diphosphonate ethane-1-hydroxyl, 1-diphosphonic acid (EHDP) suppressed bone induction. It is suggested that for bone induction to occur in soft tissues, three conditions must be present: 1) an inducing agent; 2) an osteogenic precursor cell; and 3) an environment which is permissive to osteogenesis. The presence of osteogenic inhibitors in spleen, liver and kidney is postulated.

Animals↗
PubMed1975

Safety of heavy metals as nutritional markers.

The nutritional safety of La, Sm, Eu, Tb, Dy, Tm, Yb, Sc and Cr oxides and barium sulfate were studied in two species. The mouse study was conducted for three generations, including reproduction. During the three generations the mice were apparently not effected by quantities of metals in the feed which were 1000 times the anticipated levels. This level of metals did not exhibit any effect on the reproduction or growth of the mice through three generations. It is concluded that the metals used in the diet of the mouse at any of the use levels could be used in diets for nutritional markers. The monkey study, in which 10 times the anticipated use level of heavy metal markers were fed, further illustrates the nutritional safety of the metals studied. The tissues analyzed generally illustrated that the metals were not detectable. The balance study indicated that all the metals could be accounted for and that there is no apparent absorption of these metals.

Animals↗
PubMedDate not supplied

The effect of varying oxygen tensions on hydroxyproline synthesis in mouse calvaria in vitro.

Six-day-old mouse calvaria were grown in vitro on a grid culture system in Medium 199 containing titriated proline. Gas atmospheres containing various oxygen concentrations up to 25% were introduced to influence the rate of collagen formation as determined by the synthesis of labelled hydroxyproline in the explants. There was an increase in synthesis in response to 15% oxygen with a possible further small increase in 25% oxygen. Measurement of the release of unlabelled hydroxyproline into the medium as an estimate of collagen breakdown indicates an increase in resorption with increasing oxygen concentrations up to 20%. In this model, therefore, there is increased collagen turnover with increasing oxygen tension in the physiologic range. Although the observations reflect collagen formation and do not necessarily measure bone formation, the results are consistent with data derived from other sources suggesting that bone formation is increased by improved oxygenation.

Animals↗