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Biomedical subjects

A D Mendelow

Publications and source records attributed to A D Mendelow.

At least 91 records · Page 5Linked to original sources
PubMed1993

An audit of distribution and use of guidelines for management of head injury.

Ensuring effective distribution of guidelines is an important step towards their implementation. To examine the effectiveness of dissemination of a guidelines card on management of head injury and determine its usefulness to senior house officers (SHOs), a questionnaire survey was performed in May 1990, after distribution of the cards in induction packs for new doctors and at postgraduate lectures and displaying the guidelines in accident and emergency departments and wards. A further survey, in March 1992, assessed the impact of modifying the distribution. All (175) SHOs working in general surgery, accident and emergency medicine, orthopaedics, and neurosciences on 1 February 1990 in 19 hospitals including two neurosurgical units in Northern region were sent self completion questionnaires about awareness, receipt, use, and perceived usefulness of the guidelines. 131 of 163(80%) SHOs in post responded (median response from hospitals 83% (range 50%-100%)). Over three quarters (103, 79%) of SHOs were aware of the guidelines and 82(63%) had ever possessed a guidelines card. Only 36(44%) acquired the card in the induction pack. 92%(98/107) found them useful and 81% (89/110) referred to them to some extent. Owning and carrying the card and referring to guidelines were associated with departmental encouragement to use the guidelines. Increasing the displays of guidelines in wards and departments and the supply of cards to consultants in accident and emergency medicine as a result of this survey did not increase the number of SHOs who received cards (52/83, 63%), but more (71/83, 86%) were aware of the guidelines. The guidelines were welcomed by SHOs and used in treating patients with head injury, but their distribution requires improvement. Increased use of the guidelines may be achieved by introducing other distribution methods and as a result of encouragement by senior staff.

Craniocerebral Trauma↗
PubMed1993

An evaluation of the camino ventricular bolt system in clinical practice.

The camino ventricular bolt system has been used to monitor intracranial pressure in patients after severe head injury. The correlation between the ventricular pressure measured with the Camino device and an external transducer showed that the Camino accurately measured intracranial pressure over a wide range, but that it read an average of 1.15 mm Hg higher than that obtained by the external transducer. The technique has the advantage over a remote transducer because it is sited within the ventricle. This may be of value in wave-form analysis.

Brain Injuries↗
PubMed1993

Rapid resolution of visual abnormalities with medical therapy alone in patients with large prolactinomas.

Large prolactin-secreting pituitary adenomas with suprasellar extension are often complicated by visual field defects, for which surgical decompression is the accepted treatment. However, surgical management of large prolactinomas is often not curative. This report describes a group of six unselected male patients who presented with visual field defects and reduced visual acuity due to large pituitary tumours with suprasellar extension. All six patients also had loss of libido and/or impotence. A rapid serum prolactin estimation enabled the diagnosis of prolactinoma to be made, and CT revealed a large pituitary adenoma with suprasellar extension. The patients were treated with bromocriptine, in doses increasing from 2.5 to 20 mg daily, as the sole therapy. Symptoms were relieved and serum prolactin levels were restored to normal or near normal; visual field defects resolved and visual acuity recovered in all patients. A repeat CT showed evidence of tumour shrinkage especially of the suprasellar extension, in all the patients. A diagnosis of prolactinoma should always be considered in a patient with a large pituitary tumour. The clinical history and a rapid prolactin assay will confirm the diagnosis. Treatment with bromocriptine leads to rapid improvement in perimetry and visual acuity as well as tumour shrinkage, obviating the need for pituitary surgery.

Adult↗
PubMed1993

Cortical thermal clearance monitoring in surgery for a giant middle cerebral artery aneurysm.

Cortical thermal clearance was used during surgery for clipping of a giant middle cerebral artery (MCA) aneurysm. During prolonged continuous proximal MCA occlusion thermal clearance remained normal, indicating sufficient collateral blood supply. Postoperatively the patient had no neurological deficit. This monitoring technique is a useful guide to the safety of temporary clipping during aneurysm surgery.

Cerebral Arteries↗
PubMed1993

Mechanisms of ischemic brain damage with intracerebral hemorrhage.

The results of surgical evacuation of spontaneous intracerebral hematomas are disappointing. This is largely because experimental studies have now confirmed that the brain surrounding an intracerebral hematoma develops profound and extensive ischemia. The volume of this ischemic brain may exceed the volume of the hemorrhage several times. This has been demonstrated experimentally using 14C-iodoantipyrene autoradiography in various modifications of the intracerebral hemorrhage model. These models have demonstrated that the pathophysiology of the ischemia is partly due to direct mechanical compression. There is also a component of the ischemic process induced by vasoconstrictor substances in blood. The diffuse uncontained type of hemorrhage (subarachnoid or intraventricular) causes a global reduction in cerebral perfusion pressure. The focal ischemic event is initiated at the time of hemorrhage and is largely irreversible. The experimental evidence to date indicates that neuroprotective agents (calcium channel blockers and N-methyl-D-aspartate receptor antagonists) reduce ischemic brain damage. Similarly, in immunosuppressed animals the amount of brain edema that follows the initial ischemic insult was reduced. These studies indicate that pharmacological neuroprotective strategies can minimize the brain damage that follows intracerebral hemorrhage. Early removal of the mass lesion may play a role, but it is unlikely to reverse the ischemic process if it is the only treatment offered.

Animals↗
PubMed1992

Prognostic implications of p53 protein, epidermal growth factor receptor, and Ki-67 labelling in brain tumours.

The expression of p53 protein, epidermal growth factor receptor (EGFR), and Ki-67 nuclear antigen was examined by immunohistochemistry in biopsies of 16 types of human brain tumours, including 43 astrocytomas. P53 protein, almost certainly its mutant form, was expressed in seven of the 16, and EGFR in 11 of the 16 types of tumours. In astrocytomas both the proportion of tumours which expressed p53 or EGFR increased with grade of malignancy as did the mean Ki-67 labelling index (LI): p53-0% in grade 1, 17% in grade 2, 38% in grade 3, 65% in grade 4; EGFR-0% in grade 1, 33% in grade 2, 85% in grade 3, 95% in grade 4; mean Ki-67 L1-1.1% in grades 1 and 2, 8.3% in grade 3, and 13.4% in grade 4. Astrocytomas which expressed p53 or EGFR had a significantly higher Ki-67 LI at P less than 0.05 (11.8% and 10.7%, resp.) than those that did not (6.2% or 4.1%, resp.). Patients with astrocytomas expressing p53 or EGFR had a significantly reduced survival (P = 0.035 and P = 0.007, resp.): only 11% of the p53 + ve and 13% of the EGFR + ve patients were alive at 100 weeks following diagnosis compared to 36% of p53-ve or 60% of EGFR-ve patients. Patients with Ki-67 LI greater than 5% had a reduced survival (P less than 0.0001)--none survived beyond 86 weeks following diagnosis, whilst 63% of patients with less than 5% positive cells were still alive at 100 weeks. The univariate analysis showed that in astrocytomas expression of p53 mutants, EGFR protein, and Ki-67 greater than 5% are associated with malignant progression and poor prognosis. The multivariate analysis revealed that only tumour grade and Ki-67LI were independent prognostic factors for survival.

Adolescent↗
PubMed1992

A thermal clearance probe for continuous monitoring of cerebral blood flow.

Thermal clearance has been used as a measure of tissue blood flow for over 60 years. We have developed a probe which can be used to monitor cerebral cortical thermal clearance in patients suffering from acute neurosurgical disorders. Despite its limitations of size, invasiveness, small sample volume, and difficult quantification it has proved a reliable method, showing a good correlation between measured thermal clearance and the onset of clinical signs of ischaemia.

Adult↗
PubMed1992

The effect of immunosuppression on the development of cerebral oedema in an experimental model of intracerebral haemorrhage: whole body and regional irradiation.

The oedema which forms around an intracerebral haemorrhage has a complex aetiology. The immune response may have a role in its formation. There is clinical and experimental evidence that circulating leucocytes and platelets may mediate oedema formation. Global depletion of circulating leucocytes and platelets by whole body irradiation in a rodent model of intracerebral haemorrhage was found to confer protection against both ischaemia and oedema formation. This was not a direct effect of irradiation of the brain. The possible mechanisms for this protection are discussed.

Animals↗
PubMed1991

Closed loop blood pressure control for cerebral perfusion studies.

A method is presented which maintains mean arterial blood pressure at predetermined values during cerebrovascular occlusion studies in a rat model. The system consists of a pressure measurement apparatus, a pump capable of infusing and withdrawing fluids, and a personal computer to control the infusion and withdrawal rate. An evaluation of the system is presented, and potential advantages and difficulties are discussed.

Animals↗
PubMed1991

Triphenyltetrazolium chloride (TTC) as a marker for ischaemic changes in rat brain following permanent middle cerebral artery occlusion.

Triphenyltetrazolium chloride (TTC) was used to delineate ischaemic lesions in the rat brain at various times following middle cerebral artery occlusion. A comparison was made of TTC staining by immersion and perfusion techniques and conventional light microscopy. The lesions were quantified by measuring the ischaemic area at the sections corresponding to 7 mm in front of the AO line (atlas of Konig and Klippel). In animals examined 24 h after middle cerebral artery occlusion (MCAO), the area of infarction was 17.4 +/- 1.3 mm2 on the TTC perfused slices and 17.6 +/- 1.6 mm2 on the TTC immersed slices (mean +/- SEM). By contrast, there was a marked difference between the two TTC methods when tissues were examined at shorter intervals after artery occlusion. In the TTC-perfused animals, there was no significant difference between the mean areas of infarction measured at 5-20 min, 3-4 h, or 24 h post occlusion. Immersion in TTC, however, failed to reveal any consistent ischaemic damage when applied at the earlier post-occlusion times. Conventional histopathology demonstrated minimal lesions at 5-20 min but at 4 h or more the lesions were not significantly different from those demonstrated by TTC perfusion. TTC immersion staining can, thus, only be used as a reliable marker of cerebral ischaemia damage with post-occlusion survival periods of 24 h. TTC perfusion staining gives results not significantly different from histopathology at 4 h or more post-occlusion but at earlier intervals than 24 h it differs significantly from TTC immersion staining.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Subarachnoid haemorrhage in Wegener's granulomatosis, with negative four vessel angiography.

Two patients with Wegener's granulomatosis and spontaneous subarachnoid haemorrhage are presented in whom four vessel angiograms were normal. The diagnosis of Wegener's granulomatosis should be considered in patients with subarachnoid haemorrhage and negative four vessel angiography. The presence of antibodies to a neutrophil cytoplasmic antigen may be of diagnostic value.

Adult↗
PubMed1990

Risks of acute traumatic intracranial haematoma in children and adults: implications for managing head injuries.

OBJECTIVE: To determine the factors influencing the risk of an acute traumatic intracranial haematoma in children and adults with a recent head injury. DESIGN: Prospective study of incidence of risk factors in samples of patients attending accident and emergency departments and in all patients having an acute traumatic intracranial haematoma evacuated in one regional neurosurgical unit during 11 years. SETTING: Accident and emergency departments in Scotland or Teesside and regional neurosurgical centre in Glasgow. PATIENTS: 8406 Adults and children (less than or equal to 14 years) who attended accident and emergency departments and 1007 consecutive patients who had an operation for an acute traumatic intracranial haematoma. Data were complete in 8366 and 960 patients respectively. RESULTS: Overall, children were less at risk than adults (one in 2100 v one in 348 respectively). In both age groups the presence of a skull fracture and changes in conscious level permitted identification of subgroups of patients with widely differing degrees of risk. In children the absolute risk ranged from one in almost 13,000 without a fracture or altered conscious level to one in 12 for a child in a coma and with a fracture; the pattern was similar in adults, the risks in corresponding groups ranging from one in almost 7900 to one in four. CONCLUSIONS: Although children attending hospital after a head injury have a lower overall risk of a traumatic haematoma, the main indicators of risk, a skull fracture and conscious level, are the same as in adults, and the pattern of their combined effect is similar. Guidelines for managing adults with recent head injury may therefore be applied safely to children; with the increasing provision of facilities for computed tomography they should be revised to ensure early scanning of more patients with head injury.

Acute Disease↗