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Biomedical subjects

N Evans

Publications and source records attributed to N Evans.

At least 19 recordsLinked to original sources
PubMed1992

Racial differences in the anatomical distribution of colon cancer.

The objective of this study was to determine whether racial differences exist with regard to the anatomical distribution of adenocarcinoma of the colon. We conducted a retrospective study of consecutive patients with primary colon cancer seen during a 12-year period (1976 to 1987) identified by the Rush Tumor Registry. The setting was a large, tertiary-care, private medical center, located in the inner city of Chicago, Ill. A chi 2 unpaired Student's t test of association was performed to detect any statistically significant difference in the anatomical sites of distribution between blacks and whites. A statistically significant percentage of black patients had proximally located primary colon lesions compared with white patients. This observation was independent of the actual anatomical definition of right-sided or proximal colon lesions. These findings suggest that a significant percentage of black and white patients are less likely to be diagnosed with colon cancer at a more curable stage, when abiding by the current screening guidelines of the American Cancer Society and the National Cancer Institute. The impact is greater on black patients with adenocarcinoma of the colon.

Adenocarcinoma↗
PubMed1992

Dipylidium caninum in an infant.

The tapeworm, Dipylidium caninum, occurs worldwide in dogs and cats. It may occur rarely in children, when the infection may be unrecognised or misdiagnosed. We report such a case.

Cestode Infections↗
PubMed1992

Effect of patency of the ductus arteriosus on blood pressure in very preterm infants.

Forty one preterm infants (birth weight < 1500 g) were studied by daily Doppler echocardiography for the first week of life to examine the effect of a haemodynamically significant ductus arteriosus (HSDA) on systemic blood pressure. Hourly records of blood pressure were averaged for each infant to produce a 24 hour mean value and the infants were then allocated to groups according to whether, by echocardiographic criteria, there was a HSDA on that day. In infants from 1000 to 1500 g the differences in all parameters of blood pressure between those with and without a HSDA were not significant. In infants < 1000 g the mean blood pressure was significantly less in the infants with a HSDA throughout the first week of life. Systolic blood pressure was reduced by as much as diastolic blood pressure and as a result the pulse pressure did not differ. Infants < 1000 g with a HSDA were given more plasma and a greater number received inotropic support. Gestational age, respiratory disease severity, and complication rates did not differ between those with and without a HSDA. The possibility of a clinically silent HSDA should be considered before large amounts of plasma volume expanders are given to treat hypotension in infants < 1000 g.

Blood Pressure↗
PubMed1990

Perianal appearances associated with constipation.

The perianal appearances were studied prospectively of 136 constipated children (mean age 3.9 years, 67 boys, 69 girls). Anal dilatation, fissures, tags, warts, perianal oedema, redness, blueness, and veins were recorded. It was noted whether dilatation occurred immediately or at 30 and 60 seconds with the buttocks minimally separated, and on subsequent firm lateral traction of the buttocks. The degree of faecal loading was assessed in all children. Anal dilatation was found in 24 (18%) and first appeared on lateral traction in eight (6%). In three quarters of the children with dilatation faecal loading or perianal signs were present. Fissures were found in 35 (26%) children and tags in seven (5%). Perianal redness was more likely to be associated with fissures, and blueness with dilatation. We conclude that there are no pathognomonic perianal signs in childhood constipation and that the technique of anal examination should be standardised.

Adolescent↗
PubMed1989

Out-patient lumbar radiculography with iohexol.

A prospective study of 200 patients undergoing lumbar radiculography using 10 ml iohexol (240 mgI/ml) was undertaken to determine whether the procedure could be safely performed on an out-patient basis. No statistically significant differences in the incidence and severity of side-effects were found between the 99 out-patients and 101 in-patient controls. Three out-patients had to be kept in hospital at the end of the observation period and a further three out-patients were re-admitted to hospital because of severe side-effects. Out-patient lumbar radiculography is a safe procedure provided there is careful patient selection, adequate advice and easy access to medical help should problems arise following the examination. Adopting this practice considerably reduces the cost of lumbar radiculography and indirectly increases the availability of orthopaedic beds.

Ambulatory Care↗
PubMed1989

Treacher Collins prize essay. The significance of nystagmus.

Nystagmus occurs in a very wide range of circumstances, each type showing characteristic clinical, pathological and electrophysiological features, and analogies between them can be identified by comparing and contrasting nystagmus of different kinds. The effect of altered visual and vestibular conditions on nystagmus, and the features of its waveform, indicate the relationship between eye movements and vision, and the influence of visual and vestibular input in stabilising steady fixation. Ultimately, the significance of nystagmus is that it indicates the state of the mechanisms underlying this stabilisation: in physiological nystagmus they are operating successfully, and in pathological nystagmus they are disturbed. More than this, investigation of nystagmus has shown that the visual system is not divided in a clear-cut way into sensory and motor poles, but that between them there exists a neural region where a 'copy' of the visual world is matched with a programme of potential eye movements, and where sensorimotor information exists indivisibly. Long feedback loops, involving occipital cortex and extraocular muscle proprioceptors, and short ones within the cerebellum and integrator, emphasise the great precision involved in eye movement control, enabling the visual cortex to make optimal use of the resolution capabilities of the fovea. Nystagmus always reflects an asymmetry in the output of the eye movement generators, and it has been shown that the inappropriate movement which is responsible for pathological nystagmus is the slow movement. This may arise because of an intrinsic defect in that part of the generator called the neural integrator, or because of 'tonic imbalance' in its input. Nystagmus occurring with identifiable acquired central nervous pathology can, to some extent, be understood mechanistically, but idiopathic congenital nystagmus poses greater difficulties. Analysis of its waveform suggests that an intrinsic fault in the integrator can explain the clinical and electrophysiological findings in CN, but the cause of the high gain instability in the integrator remains to be explained. The integrator is adaptable, or self-tuning, adjusting its output by visual feedback. Circumstantial evidence suggests that the original disorder in idiopathic CN may occur higher than the integrator, detuning it by conveying an inappropriately organised visual input. In particular if the organisation of the visual system into fields is defective, the gaze generators, whose output is orientated according to field, will have a less accurate 'copy' of the world from which to formulate their movements.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Outpatient lumbar radiculography: comparison of iopamidol and iohexol and a literature review.

A prospective study of 261 patients undergoing lumbar radiculography using 12 ml iopamidol (200 mgI/ml) was undertaken to determine whether the procedure could be performed safely on an outpatient basis. No statistically significant differences in the incidence and severity of side-effects were found between the 132 outpatients and 129 inpatient controls. Nine outpatients had to be kept in hospital at the end of a 4-h observation period and a further two outpatients were re-admitted to hospital because of severe side-effects. The current study was compared with a preceding study of identical design, already published, in which 200 patients underwent lumbar radiculography with 10 ml iohexol (240 mgI/ml). No statistically significant differences in the incidence and severity of side-effects between the two contrast media were evident up to 24 h after the examination. In the period between 24 h and 7 days, the incidence and severity of headache, nausea and dizziness were all significantly greater in the iopamidol group. Although outpatient radiculography can be performed safely with both contrast media, the higher incidence of delayed side-effects in the iopamidol patients prompts the authors to express a preference for iohexol for intrathecal use. The increased incidence of adverse reactions in female patients and the literature comparing iopamidol and iohexol for myelography are discussed.

Ambulatory Care↗
PubMed1988

Biometeorological triggers in childhood asthma.

The relationship between child asthma admissions and biometeorological factors was investigated over a 16-month period. No relationship was found with many commonly suspected precipitants such as temperature, humidity and wind. There was however a strong association with rainfall (P much less than 0.001). Associations occurred with low barometric pressure and counts of coloured basidiospores and green algae, but no significant relationship was found with grass pollen.

Adolescent↗
PubMed1988

Fatigue fractures of the proximal tibia simulating malignancy.

The clinical and radiological features of nine fatigue fractures developing along the soleal line of the posteromedial cortex of the proximal tibia are described. Seven patients were referred with the diagnosis of a probable malignant sarcoma of bone. All nine patients were male and all but one were 18 years of age or less. Only two gave a history of a recent increase in physical activity. The plain radiographic findings consisted of an uninterrupted, lamellar, periosteal reaction arising medially and posteriorly in the proximal tibia with the fracture seen through the thickened posterior cortex. Bone scan revealed a fusiform focus of increased uptake in the posteromedial cortex of the tibia with varying degrees of activity in the adjacent metaphysis. Computed tomography, on a soft-tissue window, showed perifracture oedema and the absence of a soft-tissue mass. The attenuation of the underlying medulla was increased as a result of fibrosis and hyperaemia. On an extended window setting, both periosteal and endosteal callus was identified, maximal in the posteromedial tibia, and the fractures, multiple in two cases, were best demonstrated on a cortical window. Clinical and radiological features that differentiate a fatigue fracture of the tibia from a sarcoma are discussed.

Adolescent↗
PubMed1986

Macrophage depletion of mouse lung following inhalation of 239PuO2.

Changes in the free-cell population of the lungs of two strains of mice (SAS/4 and CBA/H) were studied up to 4 months after inhalation exposure to a sized fraction of 239PuO2 particles (1.5 micron AMAD) to give initial alveolar depositions (IADs) ranging from 17 to 810 Bq. A sample of the free-cell population of the lung was recovered by bronchoalveolar lavage, and a radiometric method was used to estimate the total number of pulmonary alveolar macrophages (PAM) in the lung. The response of the lung to 239PuO2 was characterized by an initial, dose-dependent depression in the total number of PAM following an IAD as low as 50 Bq. At IADs greater than 150 Bq, the initial depression continued for longer, merging into a chronic phase in which the PAM were larger and were accompanied by a minor infiltration of leukocytes. These findings were confirmed by histology, which also revealed focal accumulations of Type II pneumocytes. The results indicate that inhaled alpha-emitting particles are effective at producing a depletion in the alveolar macrophage population at relatively low IADs and that chronic effects on the cells can be produced by higher concentrations.

Aerosols↗