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D A Crooks

Publications and source records attributed to D A Crooks.

13 recordsLinked to original sources
PubMed2004

The immunohistochemical localisation of somatostatin receptors 1, 2, 3, and 5 in acoustic neuromas.

AIMS: Acoustic neuroma is a benign tumour, which develops through an overproliferation of Schwann cells along the vestibular nerve. Somatostatin is a naturally occurring peptide, which exerts antiproliferative and antiangiogenic effects via five membrane bound receptor subtypes. The aim of this study was to determine whether somatostatin receptor subtypes (SSTRs) 1, 2, 3, and 5 are present in acoustic neuromas. METHODS: The expression of SSTRs 1, 2, 3, and 5 was studied in both the Schwann cells and blood vessels of eight acoustic neuroma specimens, by means of immunohistochemistry using novel rabbit polyclonal antibodies raised against human SSTR 1, 2, and 5 subtype specific peptides, and a commercial anti-SSTR3 antibody. RESULTS: SSTR2 was the most prevalent subtype in Schwann cells (seven of eight), with intermediate expression of SSTR3 (six of eight), and lower expression of SSTRs 1 and 5 (four of eight and five of eight, respectively). There was ubiquitous vascular expression of SSTR2, with no evidence of SSTR 1, 3, or 5 expression in blood vessels. CONCLUSION: SSTRs 1, 2, 3, and 5 are differentially expressed in acoustic neuromas. Somatostatin analogues may have a therapeutic role in the management of this rare and challenging condition.

Adult↗
PubMed1992

Axonal injury in closed head injury by assault: a quantitative study.

Due to the controversy in the literature regarding the time course of axonal balloon formation in human material, we wished to determine if it was possible to diagnose axonal injury before the development of axonal balloonings. The hypothesis was that the presence of axonal swellings or axonal enlargements associated with a glial reaction could be used as a diagnostic aid in human axonal injury before 12 hours. The brains of eight individuals that survived for less than 48 hours following head injury, and also had evidence of axonal injury using the criteria of Vanezis et al. (1987), were systematically studied by looking at axonal swellings, axonal balloonings, reactive astrocytes, maximum diameter of axonal enlargements and density of axonal enlargements. Controls were eight selected cases without neurological disease. The variables studied were assessed in 25 fields from ten different areas of the brain, using silver stains and immunoperoxidase for glial fibrillary acidic protein (GFAP). Logarithms of one plus the count of each variable were taken from the raw data and these were analysed using percentile distribution and the median, the t-test, Mann-Whitney U test and the Wilcoxon signed rank test. We conclude that quantitation of axonal damage allows the detection of mild degrees of axonal injury that could be overlooked on routine examination, and that the criteria of axonal enlargements, rather than axonal balloonings, are indications of axonal damage, cannot be endorsed with the evidence provided.

Axons↗
PubMed1991

Pathogenesis and biomechanics of traumatic intracranial haemorrhages.

Intracranial haemorrhage is frequently seen by the general pathologist in the context of neural trauma. Thus, the differential diagnosis, pathogenesis and biomechanics are of practical interest in the routine work. Extradural haematomas are produced when branches of the middle meningeal vessels are lacerated. They are commonly located in the temporal fossa, and other intracranial haematomas may be present. Skull fractures occur in a high percentage of cases and play a key role in the pathogenesis of this type of bleeding. Acute subdural haematomas commonly arise from tearing of the bridging veins. They are often located in the temporal and frontal regions, and the morbidity and mortality are related to the extent of the underlying brain damage. The visco-elastic behaviour of the bridging veins and their lack of reinforcement by arachnoid trabecula in the subdural space explains why they tear under high rates of acceleration during trauma. Subacute and chronic subdural haematomas are weakly correlated with trauma. The less striking onset of symptoms may be related to the rate of blood accumulation and the capacity of the brain to accommodate the mass effect of the bleeding. Intracerebral haematomas are probably due to the direct rupture of the intrinsic cerebral vessels. The mortality rate shows no correlation with location, but those located in the basal ganglia are compatible with a good recovery when occurring in isolation. Traumatic subarachnoid haemorrhage, when in isolation, is usually associated with evidence of injury elsewhere, such as the neck muscles or the ligamentary system of the cervical spinal column. It may be secondary to intraventricular bleeding due to tearing of the tela choroidea, or associated with contusions.

Biomechanical Phenomena↗
PubMed1991

The glial reaction in closed head injuries.

The development of the glial reaction in human closed head injury has been investigated using morphometry and statistical analysis. The brains of eight individuals that survived less than 48 h following closed head injury were analysed using immunoperoxidase for glial fibrillary acidic protein (GFAP). Controls were eight patients without neurological disease. The density of reactive astrocytes was estimated in 25 fields in each of 10 different areas sampled bilaterally avoiding the subpial and subependymal zones, and the perivascular white matter. There was great variation between the zones within and between groups, and considerable variation between individuals. The raw data were expressed as logarithms averaged and analysed using the median and non-parametric statistics. The corpus callosum in the head injury group showed the highest densities of reactive astrocytes, particularly in the splenium which achieved statistical significance using the non-parametric tests. This pattern was not reproduced in the control group. Although there was overlap between the head injured and control individuals, the head injury group had relatively higher densities in all zones, and showed an overall increase in the density of reactive astrocytes. This achieved statistical significance in the corpus callosum, the occipital subcortical white matter, and the cerebellum. This study has shown that the glial reaction is often prominent in the corpus callosum irrespective of the presence of a primary lesion although the pattern varies from case to case.

Adult↗
PubMed1991

A method to quantitate axonal injury.

The quantitation of diffuse axonal injury provides a more objective approach to the assessment of tissue damage in head injuries. The method designed in this study takes into account the anisotropy and structural inhomogeneity of the brain, and the distribution of lesions in diffuse axonal injury. The number of counts required for the statistical analysis is inversely proportional to the square of the desired accuracy, specified as the percentage of the mean value of the axonal balloons since the true mean is unknown from the outset. The number of fields are examined using an indexed-squares graticule in 10 different areas of the brain. Silver-stained sections from the brains of head injured patients that survived longer than 12 h must be used with this method. Difficulties may arise when patients of different survival times are compared since it takes some time for the axonal balloons to develop. A correlation with the survival time can be established with the quantitative data collected. The morphometric principles and the statistical rationale on which this methodology is based are briefly presented.

Axons↗
PubMedDate not supplied

Epidemiology of central nervous system tumors in children and young adults (0-29 years), Yorkshire, United Kingdom.

The authors describe the incidence and survival of 480 patients diagnosed under 30 years with a CNS tumor in Yorkshire, UK, between 1990 and 2001. The effect on survival from deprivation and other prognostic factors was examined. Young adults (aged 15-29) were significantly less likely to develop CNS tumors than children (p = .001), largely because of an excess of medulloblastoma and ependymoma in the pediatric age range. No significant temporal trends in incidence were present apart from young adults with "other CNS" tumors showing an average annual increase of 10.7% (95% CI 1.3-21.0%; p = .03). Young adults had significantly lower survival rates than children (hazard ratio = 1.52, 95% CI 1.10-2.10). The highest risk of death was observed for patients from the most affluent areas. The overall burden of CNS tumors appears to be relatively constant, but the significantly poorer survival for young people needs further rapid investigation.

Adolescent↗