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Biomedical subjects

A D Mendelow

Publications and source records attributed to A D Mendelow.

At least 19 recordsLinked to original sources
PubMed1995

The Apache II scoring system in neurosurgical patients: a comparison with simple Glasgow coma scoring.

In order to compare the predictive value of the Apache II, the Glasgow Coma Scale and Revised Trauma Scoring systems in relation to outcome in a neurosurgical department high dependency unit (HDU), all 109 patients entering the unit under the care of one consultant were studied. All patients in the HDU were self-ventilating, so that motor responses were not suppressed by muscle relaxants or sedation. Initial Minimum and Maximum Glasgow Coma Scale Scores, Revised Trauma Score, Apache II and the Apache minus neurological weighting (Apache-NW) scores, were compared as predictors of outcome (as assessed by the Glasgow Outcome Score at 6 months). Twenty-eight patients had a bad outcome, i.e. Glasgow Outcome Scores 1-3, and 72 individuals a good outcome, i.e. scores 4 or 5. Statistical analysis was by the Spearman Ranked Correlation Test, and comparison of Receiver Operational Characteristics Curves. Data were complete on 100 patients (91.7%) and show the Maximum Glasgow Coma Score, followed by the Apache II score, as the best predictors of outcome analysed. This was also true if all patients except those with head injury were analysed as a group. All scoring systems were significantly better predictors of outcome in the head injured patient. For this group, Apache II had an outcome predictive value of 97% compared with 93% for initial and 95% for minimum GCS. Removing the neurological weighting from Apache II weakened its predictive ability in all patients, emphasizing that it is the neurological status of the patient which best predicts overall functional outcome. Apache II data are also much more time-consuming to collect than GCS data.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Injuries↗
PubMed1995

Experimental stroke and neuroprotection in the aging rat brain.

BACKGROUND AND PURPOSE: Experimental stroke research has for the most part incorporated the use of young animals despite the importance of aging in cerebrovascular disease in humans. We hypothesized that age-related reductions in the density and function of cortical N-methyl-D-aspartate (NMDA) receptors might limit neuroprotective potential in the elderly. In this study, a model of occlusive stroke in the aging rat brain has been developed and used to establish the effects of age on cerebral infarction and to evaluate the scope for protecting the aging brain during ischemia. METHODS: Focal cerebral ischemia was produced by thermocoagulation of the left middle cerebral artery in adult (11 to 17 months) and aged (28 to 36 months) male Wistar rats. Infarcts were assessed histologically with volumetric analysis of infarct size, hemodynamically by serial cerebral blood flow measurement using the hydrogen clearance technique, and by analysis of specific gravity as an index of brain edema. Neuroprotective potential was assessed using the competitive NMDA receptor antagonist 3-(2-carboxy piperazin-4-yl)propyl-1-phosphonate (D-CPPene). RESULTS: Aging was associated with a significant increase in infarct size, with a mean infarct volume of 40.5 +/- 2.6% of the hemisphere volume in aged rats compared with 30.9 +/- 0.7% in adult rats (P < .01). D-CPPene reduced the mean infarct volume to 33 +/- 1.8% and 20.7 +/- 3.2% in aged and adult rats, respectively (P < .05). Cerebral blood flow fell markedly after infarction, but thereafter D-CPPene-pretreated rats maintained higher cerebral blood flow than untreated animals throughout the duration of the experiment (22.8 +/- 3.2 and 30.1 +/- 5.5 mL.100 g-1.min-1 in treated aged and adult rats, respectively, compared with 11.3 +/- 2.7 and 16.5 +/- 3.2 mL.100 g-1.min-1 in untreated aged and adult groups, 90 minutes after infarction [P < .05]). Pretreatment also reduced cortical edema; mean cortical specific gravity 4 hours after infarction was 1.0381 +/- 0.0013 in untreated aged rats and 1.0391 +/- 0.0014 in untreated adults compared with 1.0458 +/- 0.0031 in treated aged rats and 1.0442 +/- 0.0014 in treated adult rats (P < .05). CONCLUSIONS: Under similar experimental conditions, there was an age-related increase in cerebral infarct size. However, NMDA receptor antagonism was neuroprotective in the aging brain and resulted in a significant reduction in cerebral ischemic damage, less cortical edema, and preservation of cerebral blood flow.

Aging↗
PubMed1994

Cerebral oedema following intracerebral haemorrhage: the effect of the NMDA receptor antagonists MK-801 and D-CPPene.

The effects of pre-treatment with the NMDA receptor antagonists MK-801 and D-CPPene on the development of brain oedema were investigated in a rodent model of intracerebral haemorrhage. In acute experiments (4 hour survival) both drugs caused significant hypotension and had significant anaesthetic effects whilst conferring no protection against oedema formation. In chronic experiments (24 hour survival) MK-801 conferred no protection against brain oedema. With D-CPPene marginal protection against cortical oedema may have been conferred but this result should be interpreted with caution.

Animals↗
PubMed1994

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

Cortical thermal clearance provides a practical means of continuous assessment of cerebral blood flow. A probe which can be used to monitor cerebral cortical thermal clearance is described. It has proved a reliable method of predicting oligaemia, showing good correlation between measured thermal clearance and the onset of clinical signs of ischaemia. The limitations are its size, invasiveness, small sample volume and difficulty with quantification. It is a useful additional tool in the management of patients suffering from acute neurosurgical disorders.

Blood Flow Velocity↗
PubMed1994

The effect of age on cerebral oedema, cerebral infarction and neuroprotective potential in experimental occlusive stroke.

A model of occlusive stroke in the aging brain has been developed and used to evaluate the effects of age upon cerebral infarction, cerebral oedema and neuroprotective potential. Focal ischaemia following left middle cerebral artery occlusion has been compared in aged (30 month) and adult (< 17 month) rats, with histological assessment of infarct volume and analysis of specific gravity as an index of cerebral oedema. Aging was associated with a significant increase in cerebral infarct size. The mean infarct volume in aged rats was 40.5% +/- 2.6% of the hemisphere volume, compared to 30.9% +/- 0.7% in adults (p < 0.01). Pre-treatment with the competitive N-Methyl-D-Aspartate (NMDA) receptor antagonist 3-(2-Carboxy Piperazin-4-yl)Propyl-l-Phosphonate (D-CPP-ene) reduced infarct volumes in both age groups to 33.0% +/- 1.8% and 20.7% +/- 3.2% in aged and adult animals, respectively (p < 0.05). There was significantly less oedema of the cerebral cortex in D-CPP-ene pre-treated rats; mean cortical specific gravity 4 hours post-infarction was 1.0381 +/- 0.0013 in untreated aged rats and 1.0391 +/- 0.0014 in untreated adults, compared to 1.0458 +/- 0.0031 in treated aged rats and 1.0442 +/- 0.0014 in treated adults (p < 0.05). At 24 hours post-infarction, D-CPP-ene pre-treated aged rats had a mean cortical specific gravity of 1.0403 +/- 0.0006 compared to 1.0361 +/- 0.0014 in untreated aged animals (p < 0.05). This study has demonstrated an age-related increase in cerebral infarct size, but has shown that the aging brain is amenable to neuroprotection by NMDA receptor antagonism.

Age Factors↗
PubMed1994

Anterior cervical discectomy: an improvement in donor site operative technique.

Bone graft harvest from the iliac crest for anterior cervical discectomy is common surgical practice. Its rate of complication remains far higher than that of the cervical operation. We describe a method of harvest that we believe reduces post-operative complications and pain, facilitating early patient mobilization and discharge.

Bone Transplantation↗
PubMed1993

Post-traumatic bilateral facial palsy.

Bilateral facial palsy is an uncommon condition and few clinicians have experience of more than the occasional case. Unlike its unilateral counterpart, an aetiological factor is often demonstrable. A wide variety of recognized diseases may give rise to the condition and thus thorough investigation is required. This paper presents an unusual example of this rare condition.

Adult↗
PubMed1993

The management of carotid artery disease: application of new diagnostic techniques and their neuropathological significance.

The early management of patients with carotid artery disease was based on minimal investigative knowledge without much appreciation of its pathophysiological significance. During the last decade, however, the advent of non-invasive and functional imaging has increased our awareness and the significance of extracranial cervical vascular disease. This has led to more logical management strategies particularly for patients with carotid artery disease. Non-invasive imaging, in particular, has identified patients at risk and led to the establishment of large randomized trials of medical and surgical treatments, the recent results of which have altered management practice.

Carotid Artery Diseases↗
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↗