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Biomedical subjects

E Armstrong

Publications and source records attributed to E Armstrong.

At least 91 records · Page 5Linked to original sources
PubMed1986

The evaluation of choanal atresia by computed tomography.

The radiographic evaluation of choanal atresia has traditionally consisted of a nasopharyngeal contrast study, however, this procedure has certain diagnostic limitations. The contrast nasopharyngogram does not define the type or thickness of the atresia. Computed tomography (CT) accurately characterizes the nature and thickness of the atresia, and visualizes the associated thickening of the vomer and narrowing of the posterior nasal cavity. CT evaluation with three dimensional reconstruction adds an additional diagnostic dimension. Seven patients have been evaluated by CT. The results show CT is a cost effective method to clearly define the abnormal anatomy. CT is the radiographic procedure of choice in the evaluation of choanal atresia.

Airway Obstruction↗
PubMed1986

Imaging the pediatric liver: MRI and CT.

The livers of 27 children, 2 weeks to 16 years old, were examined with MRI and CT. Fourteen children had normal livers, 9 had focal liver disease, and 4 had diffuse liver disease. Normal intrahepatic venous anatomy was visualized more frequently with MRI than with CT, regardless of presence of disease, type of disease, or age. Focal hepatic lesions were either iso- or hypointense on relatively T1-weighted images and were hyperintense on T2-weighted images regardless of the pathology. In three cases, lesions seen with MRI were not detected with CT. In two other cases, CT was interpreted as equivocal or abnormal, but the liver was normal on MRI. MRI was superior to CT for evaluation of patency of the intrahepatic portion of the inferior vena cava. Other than in cases of fatty infiltration, CT provided no information additional to MRI. MRI has the potential to replace CT as a technique for imaging the pediatric liver in many cases, especially for infants and young children.

Adolescent↗
PubMed1985

Relative brain size in monkeys and prosimians.

Prosimians have smaller brains relative to their body sizes than do monkeys. Brain and body weights, however, are associated not only on the basis of the brain integrating sensorimotor functions, but also on the basis of the body's requirement to support the energetic needs of the brain. Prosimians differ from monkeys in that they have lower rates of oxygen turnover. When body size is adjusted for its rate of oxygen turnover, monkeys and prosimians have equivalent relative brain sizes. A consideration of the brain's energy requirements helps to clarify brain-body relationships.

Animals↗
PubMed1985

Relative brain size and metabolism in birds.

Earlier studies have shown that the negatively allometric brain-body weight association in mature mammals changes to an isometric association when body weights are adjusted for their rates of oxygen consumption. Birds are endogenous homeotherms, and so their brain weights were analyzed according to their body weights and metabolism (estimated energy supply). As expected, the brain and body weights of the 83 species of neognathid birds have a negatively allometric association. The same species, however, have a brain weight-to-estimated energy supply which cannot be separated from isometry. While passerines have bigger brains for their body weights than altricial nonpasserines, the relative brain sizes of the two avian groups cannot be separated once the metabolic rate is used to adjust the body weights. Ratites or paleognathid birds may have a different brain-to-metabolism association. Consideration of bioenergetics helps clarify brain and body weight associations.

Animals↗
PubMed1983

Relative brain size and metabolism in mammals.

Comparisons of the relation between brain and body weights among extant mammals show that brain sizes have not increased as much as body sizes. Interspecific increases in brain and body size appear to occur at the same rate, however, when the amount of available energy is taken into account. After this adjustment, brains of primates are slightly larger than expected from the overall mammalian data, but primates also use a larger proportion of their total energy reserves for their brains. Analyses of relative brain size must take into account the requirements that the metabolically active brain has for the body.

Animals↗
PubMed1983

Effects of saltwater feeding and reduced food intake on femurs of domestic ducklings.

Seven-day-old domestic ducklings were assigned to groups and fed freshwater and food ad libitum (control), 1% NaCl and food ad libitum (stressed), or freshwater and only as much food as the stressed group ate (starved). Tissues were sampled after 3 and 7 days. Other groups of ducklings were fed freshwater and food ad libitum for 9 days (control), 1% NaCl and food ad libitum for 7 days followed by freshwater for 2 days (de-stressed), or freshwater and the same amount of food as the de-stressed group for 7 days followed by food ad libitum for 2 days (de-starved). Body weights were recorded and the femurs were analyzed. Univariate, multivariate, and allometric analyses clearly demonstrate that stressed and starved regimens influence femoral morphology differently. Stressing for 3 days reduced femoral ash and by 7 days had retarded femoral linear growth. Three days of starvation produced no apparent effect on the femur, but starvation for 7 days reduced the amount of femoral ash/femoral length. Furthermore, major differences between stressed and starved ducks disappeared after de-stressing for 2 days. Studies of bone growth and metabolism may benefit by using this avian model.

Animals↗
PubMed1983

Changing incidence of infantile hypertrophic pyloric stenosis.

The incidence of infantile hypertrophic pyloric stenosis was measured in the West Midlands Health Region between 1974 and 1980. It increased from 2.1/1000 Caucasian births in 1974 to 3.5/1000 in 1980 and reflects a reported increase in Central Scotland. Several artefacts were excluded--for example, repeat admissions to the same hospital, transfers to other hospitals, and changes in treatment and in diagnostic standards. Two main demographic changes were excluded as explanations, ethnic changes and changes in the birth rank distribution. The increase is therefore considered real and may be related to changes in breast feeding practice.

Birth Order↗
PubMed1982

A look at relative brain size in mammals.

While brain weight scales to body weight, the differences among brain weights are less than those among body weights. It has been assumed that this negative scaling is causally related to an isometric scaling of brain weight with surface area. For this assumption to be true, surface receptor/effector densities must be constant. Morphometric data indicate that this is not the case. Interspecific scaling of mammalian brain sizes, however, is isometric with the organisms' abilities to support the energy costs of the brain.

Animals↗
PubMed1982

Conventional metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis. A comparative study.

A retrospective examination was performed to assess the accuracy of metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis. Of 81 consecutive scoliotic children studied by myelography, 30 had only MM while the remaining 51 had CTMM immediately afterward. CTMM added essential diagnostic information in 13 cases of dysraphism and 4 cases of idiopathic scoliosis; in the remaining cases, both methods gave the same information. The authors conclude that in patients with severe scoliosis, dysraphism, and scoliosis with localized neurological disturbances, CTMM should always be added to MM or be the only examination; while in idiopathic scoliosis with vague neurological disturbances a survey of the entire spine is essential, preferably with MM.

Adolescent↗
PubMed1982

Adverse reactions to myelography with metrizamide in infants, children and adolescents. I. General and CNS effects.

A prospective investigation of the adverse effects of myelography with metrizamide was performed in a series of 250 examinations in infants, children and adolescents. Adverse reactions occurred in 58 per cent of all cases. The majority of these were mild, and seemed to be due to the lumbar puncture alone. The frequency of the moderate and marked reactions was directly related to the total amount of metrizamide given and to the cranial extension of the examination in the spinal canal. No other circumstances around the procedure had any impact on the occurrence of adverse reactions.

Adolescent↗
PubMed1981

A quantitative comparison of the hominoid thalamus. IV. Posterior association nuclei-the pulvinar and lateral posterior nucleus.

Nuclear volumes, nerve cell densities, numbers of neurons, and volumes of nerve cell perikarya in the thalamic association complex, the pulvinar and lateral posterior nuclei (Pu-LP) were compared among two gibbons, one gorilla, one chimpanzee, and three humans. The human Pu has approximately twice as many neurons as do the great apes, whereas the human and gorilla LP have a similar number. The numbers of neurons in the human Pu and combined Pu-LP complex were predictable from the ape data. Nevertheless, a shift in perikaryal sizes from a unimodal to a bimodal population distinguished the human specimen. It is hypothesized that during human evolution Pu expanded in proportion to the rest of the brain, but that not all parts of Pu expanded equally.

Animals↗
PubMed1981

The CT appearance of avulsion of the posterior vertebral apophysis. A case report.

Avulsion and posterior dislocation of the posterior dislocation of the posterior part of the vertebral apophysis is a rare condition, occurring mainly in adolescence. If the avulsed part is ossified it may be diagnosed with conventional X-rays including myelography. The present case shows that CT scan with sagittal reconstruction gives exact information of the nature of the lesion as well as its extension into the spinal canal, and that CT alone is sufficient for preoperative diagnosis.

Adolescent↗
PubMed1980

A quantitative comparison of the hominoid thalamus: II. Limbic nuclei anterior principalis and lateralis dorsalis.

Structures in the limbic system are commonly thought to be similar in form and function in all mammalian brains. In the study reported here, two thalamic limbic nuclei, N. anterior principalis and N. lateralis dorsalis, were compared among a group of extant hominoids. The nuclear volumes, neuronal densities, numbers of neurons per nucleus, and columes of neuronal perikarya were measured. Humans have much larger nuclei but the nuclei constitute a similar proportion of the whole thalamus as found in the other hominoids. Whereas the human limbic nuclei were observed to have a decrease in the densities of nerve cells compared with those of the other hominoids, this difference is less than that found in most other thalamic nuclei. Consequently the estimated number of neurons is much higher for humans. The total number of neurons best separates the human limbic nuclei from those of the other hominoids. This preliminary study suggests that during hominid evolution neurons were preferentially added to the limbic nuclei of the thalamus.

Adult↗
PubMed1979

Heart attacks and geomagnetic activity.

Malin and Srivastava reported a remarkable correlation between daily variations in the geomagnetic field strength and daily admissions to the cardio-thoracic wards of hospitals in Hyderabad and Secunderabad, for cardiac emergencies, during 1967--72. We have now carried out a similar enquiry in the West Midlands region of the UK for the years 1969--70, but were unable to confirm the Indian results.

England↗
PubMed1979

Quantitative comparison of the hominoid thalamus. I. Specific sensory relay nuclei.

Studies to date have indicated few differences in sensory perception among hominoids. Sensory relay nuclei in the dorsal thalamus--portions of the medial and lateral geniculate bodies (MGBp, LGBd) and the ventrobasal complex (VB)--in two gibbons, one gorilla, one chimpanzee and three humans were examined for anatomical similarity by measuring and estimating the nuclear volumes, neuronal densities, numbers of neurons per nucleus, and volumes of neuronal perikarya. The absolute volumes of these nuclei were larger in the larger brains; however, with the volume of the dorsal thalamus as a standard, these sensory relay nuclei showed negative allometry. The gibbons had about half as many neurons as did the other hominoids. Although the human VB had slightly more neurons, the numbers of neurons in LGBd and MGBp did not significantly differ between the great apes and humans. The volumetric distribution of the neuronal perikarya were similar among these hominoids. Other thalamic nuclei had much more diverse numbers of neurons and relative frequencies of their neuronal perikarya. The sensory relay nuclei appear to be a group of conservative nuclei in the forebrain. These results suggest that as a neurological base for complex behaviors evolved in hominids, not all parts of the brain changed equally.

Animals↗
PubMed1978

A study of the fertility of mothers of twins.

Data on all births to Birmingham residents during a ten-year period were used to compare the reproductive history of mothers immediately before and after a twin maternity with that of mothers of similar age and parity before and after a single birth. It was found that mothers of twins were less likely than mothers of singletons to have a subsequent birth if both twins survived, but if only one survived there was little difference between the two groups. If both twins died, however, the likelihood of a later birth was increased. The interval before the next birth was longer than expected when both twins survived and much shorter when both died. The sex of the twins appeared to have little influence on subsequent reproduction, in spite of the fact that for singleton-containing fraternities a further pregnancy was more likely if the first two children were of the same sex than if they were of opposite sexes. The mean interval preceding a twin maternity was almost the same as that preceding a single birth when both twins survived, but it was shorter when one twin died (being similar to that preceding the birth of a singleton who died) and it was much shorter when both twins died.

Birth Order↗
PubMed1977

Transmission of Nosema kingi to offspring of Drosophila willistoni during copulation.

Transmission of the microsporidian Nosema kingi to offspring of Drosophila willistoni during copulation was investigated. Offspring from matings of infected females and non-infected males, infected males and non-infected females, and both infected females and males were parasitized with N. kingi. 28% of the offspring were infected when the parents mated immediately after exposure to the parasite. However, 43--93% of the offspring were infected with the microsporidian when copulation was delayed 2 weeks post-infection.

Animals↗