Search PubMed⌕ Search

Biomedical subjects

P L Reilly

Publications and source records attributed to P L Reilly.

At least 37 records · Page 2Linked to original sources
PubMed1995

The native structure of intercellular adhesion molecule-1 (ICAM-1) is a dimer. Correlation with binding to LFA-1.

In solution, intercellular adhesion molecule-1 (ICAM-1) exhibits extremely low affinity for its receptor, LFA-1, as direct binding to LFA-1 has not been reported. Furthermore, there are conflicting reports on the ability of ICAM-1 in solution to inhibit cell adhesion events. These differences could be due to the valency or an oligomeric native biochemical form of membrane-bound and soluble ICAM-1, which may correlate with its ability to bind to integrins. To test this, stimulated adenocarcinoma (A549) cells or HUVEC were labeled with 35S-methionine/cysteine and treated with a chemical cross-linker. A high m.w. form (200 kDa) of ICAM-1 but not ICAM-2 was specifically immunoprecipitated from cross-linked cell lysates and supernatants. Affinity purification of crosslinked supernatants revealed that the majority of ICAM-1 was dimeric as opposed to recombinant soluble ICAM-1, which contains a minor fraction of dimer. Gel filtration chromatography was used to isolate monomeric and dimer-rich fractions of recombinant soluble ICAM-1, and tested for direct binding to affinity-purified LFA-1. Dimer-rich fractions demonstrated an enhanced ability and estimated affinity, compared with monomeric protein, to bind to purified LFA-1. These data suggest that ICAM-1 exists in its native membrane-bound and shed form as a non-covalent dimer, and that dimerization directly correlates with enhanced binding to LFA-1.

Cross-Linking Reagents↗
PubMed1995

Detection of cerebral venous desaturation by continuous jugular bulb oximetry following acute neurotrauma.

A prospective observational study was performed to assess the reliability of fibreoptic oximetric catheters and to identify the incidence and causes of jugular bulb oxygen desaturation in patients with acute closed head injury. There were twenty-five patients (30 +/- 16 years) with GCS < or = 8 in this study. Jugular bulb oximetry, mean arterial pressure, intracranial pressure, end-tidal CO2 and pulse oximetry were monitored continuously. Catheter calibration against a laboratory oximeter was performed post insertion and thereafter eight-hourly. Cerebral venous desaturation was defined as a jugular bulb oxygen saturation < 55% of > 10 minutes duration. There was a poor correlation for the first in vivo calibration (r2 = 0.602, P < 0.001, n = 25). Thereafter a close correlation between jugular bulb catheter and oximetry values was demonstrated (r2 = 0.868, P < 0.001, n = 205). Forty-two episodes of jugular bulb oxygen desaturation of 88 minutes mean duration (range 10 to 555) were observed. 83% occurred within 48 hours following injury. Hypocapnia was associated in 45% of episodes; hypoperfusion in 22%; raised ICP in 9% and a combination of the above in 24%. Validation with a laboratory oximeter is essential prior to continuous jugular bulb oximetry. Sustained episodes of cerebral venous desaturation are frequent within the first 48 hours following acute head injury. Factors such as hypocapnia and cerebral hypoperfusion that primarily reduce cerebral blood flow are predominant.

Acute Disease↗
PubMed1994

False aneurysm following intracranial surgery.

A false aneurysm of the pericallosal artery formed following resection of a colloid cyst. The aneurysm presumably resulted from arterial damage during surgery and its enlargement may have been facilitated by the surgical defect in the corpus callosum. A spherical hyperdense lesion on postoperative CT may indicate a false aneurysm.

Adult↗
PubMed1992

The relative effects of hypoxic hypoxia and carbon monoxide on brain function in rabbits.

New Zealand white rabbits were exposed to control conditions (n = 11), or to either a progressive hypoxic hypoxia produced by dilution of oxygen (O2) with nitrogen (n = 10) or a 1% carbon monoxide (CO) admixture for 15 min (n = 11). Both exposures caused a significant increase in cerebral blood flow (CBF) of up to 300% such that O2 delivery to the brain was unchanged. In the hypoxia group, a cortical somatosensory evoked response (CSER) was unaffected until the arterial O2 tension was below 20 mmHg. At this time, the rabbits became hypotensive, O2 delivery to the brain decreased dramatically and the CSER could not be elicited. In contrast, despite the maintenance of O2 delivery to the brain during and after the CO exposure, the CSER voltages were halved during the exposure and only recovered to about 80% of baseline subsequently. We conclude that the primary toxicity of CO to the brain in rabbits is not due to a reduction in O2 delivery.

Animals↗
PubMed1991

Head injuries in infants and young children: the value of the Paediatric Coma Scale. Review of literature and report on a study.

The normal verbal and motor responses embodied in the standard Glasgow Coma Scale (GCS) are not achievable during the first few years of life. The recent literature contains numerous reports of attempts to devise scales of responses quantitating the conscious level in infants and young children, both for research purposes and as clinical guides; some of these scales incorporate items, e.g. brainstem reflexes, that are not included in the GCS. We have reported on a simple paediatric version of the GCS, which uses the standard scale with minor modifications in the verbal component, and sets realistic age-related normal responses. This has been tested prospectively in a series of 60 head-injured infants and children (age range 0-72 months). Of 6 cases recorded as comatose 6 h after injury, 4 have confirmed or suspected residual disabilities. Of 35 cases considered to be fully conscious at 6 h, 31 have made good recoveries and only 1 has suspected residual disabilities. The study suggests that the scale accords with the realities of neurological immaturity, and confirms that it can be used in routine paediatric practice. For comparative therapeutic trials, the conscious level in infants has limited value as an index of brain injury, and should be complemented by other indices, such as brainstem reflexes.

Brain↗
PubMed1991

Frontofacial advancement with a free flap: deadspace versus drainage.

Presented is an adult case of Crouzon's syndrome undergoing a single stage frontofacial advancement where the employment of a microvascular free flap for extradural deadspace obliteration and to seal any communication with the nose may have contributed to the development of a major extradural infection.

Adult↗
PubMed1990

Neuropsychologic outcome after craniofacial fracture.

Forty eight patients with facial fractures resulting from trauma were admitted to a Plastic Surgical Unit. The fractures were treated on standard lines and ten of the patients required craniotomy for CSF rhinorrhea or repair of depressed frontal fractures. Neuropsychologic assessment was carried out on all patients approximately 17 months after the initial injury. An assessment of the extent to which the trauma had affected the personality and social adjustment of each individual was also carried out at that time. In four patients there was no evidence of any neuropsychologic impairment on any of the tests administered. The neuropsychologic deficits were most noticeable in those who had suffered a cranial fracture. In patients with facial fractures but no evidence of cranial fractures, there was no association between neuropsychologic impairment and site of injury. Loss of consciousness was associated with poor social adjustment and a marked change in personality. The best predictor of subsequent neuropsychologic deficits and social maladjustment was found to be the Glasgow Coma Score at the point of admission to the hospital after injury. It is concluded that with this type of injury careful neuropsychologic assessment is important in identifying the subtle deficits that might otherwise remain undetected.

Adolescent↗
PubMed1990

The effect of gas emboli on rabbit cerebral blood flow.

Many bubbles that enter the brain circulation pass through the arterioles and capillary beds and do not obstruct blood flow. Nevertheless, such bubbles could still disrupt brain function. An open-brain model in five anesthetized rabbits used the minimum dose of air (25 microliters) necessary to cause embolism of the exposed vessels, and these bubbles passed through the vessels without any trapping. Despite their rapid transit, the bubbles provoked a marked dilatation of the affected pial arterioles (mean increase after 15 minutes of 27%) that persisted for 90 minutes after the bubbles had disappeared. The changes in vessel diameter were associated with a delayed, but significant and progressive, reduction in both cerebral blood flow measured by hydrogen clearance and neural function measured by cortical somatosensory evoked response. The decrease in blood flow correlated well with the depression of neural function (r = 0.67). Because both cerebral blood flow and neural function temporarily returned to normal after air embolism, the subsequent changes seen in this model cannot be explained simply by the mechanical obstruction of blood flow by bubbles.

Air↗
PubMed1990

Increasing doses of intracarotid air and cerebral blood flow in rabbits.

We studied the natural history of brain air embolism by observing bubbles in the pial vessels of rabbits and the effect of different doses of intracarotid air on brain function and blood flow. We identified and then studied two doses of air; 25 microliters in five rabbits caused rapid bubble transit, recovery, and then deterioration in brain function and blood flow and 400 microliters in five rabbits caused temporary bubble trapping and sustained deterioration in brain function. These dose responses correlate well with the natural history of divers with air embolism of the brain. All doses of air caused both arteriolar dilatation and reduced blood flow, which were independent of dose, whereas the detrimental effect of air embolism of brain function was dose dependent. Our results suggest that this is a good model of brain air embolism.

Animals↗
PubMed1989

Isotope transport studies and shunt pressure measurements as a guide to shunt function.

Shunt function testing by radionuclide injection and shunt pressure measurement was performed in 312 cases. In our experience the test has a sensitivity of 92% and accuracy of 89%. The diagnostic value of the components of the test are discussed. The test is a safe and integral part of the assessment of shunt function. The significance of shunt malfunction must of course be determined by clinical evaluation, measures of ventricular size by CAT scanning or ultrasound, and by continuous ICP recording. However the shunt function test combined with shunt pressure measurement is a safe and essential investigation of symptomatic shunt malfunction.

Adolescent↗
PubMed1988

Assessing the conscious level in infants and young children: a paediatric version of the Glasgow Coma Scale.

The Glasgow Coma Scale is widely accepted as a measure of impaired consciousness both in clinical practice and in research. In its standard form, the scale is inapplicable to infants and children below the age of 5 years. We have devised a paediatric coma scale, which recognises that the expected normal verbal and motor responses must be related to the patient's age. This scale has been routinely used in a paediatric teaching hospital over a 10-year period and has appeared to be satisfactory, although it is less sensitive to changes in the conscious level than the adult scale. We have assessed the consistency of observer evaluation, using video tapes of infants and children exhibiting varying levels of consciousness: when conducted after formal instruction, assessments were reasonably consistent.

Child, Preschool↗
PubMed1986

Optic nerve apoplexy. Report of two cases.

Two patients who suffered loss of vision due to spontaneous optic nerve hematomas are described. The hemorrhage was contained within the pial confines of the involved optic nerve, although there was some extension more posteriorly. The diagnosis of an intraneural cryptic arteriovenous malformation was histologically confirmed in one case and was supported by evidence in the other. Surgical evacuation by the subfrontal approach was undertaken and visual function improved.

Adult↗
PubMed1980

CT of intracerebral haemorrhage due to mycotic aneurysms--case report.

The CT findings in a case of intracerebral haematoma due to rupture of a mycotic aneurysm are presented. In addition to the haematoma, CT demonstrated small focal areas of cortical enhancement, which corresponded to the peripheral aneurysms seen on angiography. Such findings are thought to be characteristic; a brief differential diagnosis is discussed.

Adult↗
PubMed1980

The clinical and radiological features of the empty sella syndrome.

The importance of the empty sella syndrome has increased with recent interest in pituitary micro-adenomas, trans-sphenoidal hypophysectomy and computerised tomography. Four cases of the empty sella syndrome which illustrate the clinical and radiological features are reported, and the literature is reviewed. Headache, visual symptoms and endocrine disturbances are commonly found in association with the empty sella syndrome, and the coexistence of pituitary micro-adenomas is well recognised. Symmetrical ballooning of the sella turcica without changes in configuration is the typical finding with plain radiography, but occasionally more extensive destructive changes in the region of the pituitary fossa may occur. Provided that the correct angulation, collimation and level of cut are chosen, computerised tomography now may be used to make a definitive diagnosis, making air encephalography unnecessary.

Adenoma↗