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R O Weller

Publications and source records attributed to R O Weller.

At least 19 recordsLinked to original sources
PubMed1992

Expression of the p53 protein in a spectrum of astrocytic tumours.

Many human cancers are characterized by mutations of p53, a nuclear phosphoprotein which controls elements of the cell cycle. Turnover of p53 in normal cells is rapid, and the minute quantities of protein that are usually present are not detected by immunocytochemical methods. Mutations of the p53 gene in tumour cells are associated with a slower turnover and subsequent accumulation of the protein in both nucleus and cytoplasm. Genetic abnormalities of the short arm of chromosome 17, which is the site of the p53 gene locus, are a feature of astrocytic tumours. Using a panel of five antibodies to p53 and a standard immunocytochemical method, we found detectable quantities of p53 in the cells of 3/16 diffuse astrocytomas, 8/14 anaplastic astrocytomas, and 24/34 glioblastoma multiforme. Progression of one patient's tumour from a diffuse to an anaplastic astrocytoma was characterized by the accumulation of p53. The more malignant histological features of anaplastic astrocytoma and glioblastoma multiforme appear to be reflected by a greater incidence of p53 accumulation.

Astrocytoma↗
PubMed1992

Directional and compartmentalised drainage of interstitial fluid and cerebrospinal fluid from the rat brain.

Pathways for drainage of interstitial fluid and cerebrospinal fluid from the rat brain were investigated by the injection of 2-5 microliters Indian ink into cerebral white and grey matter and into the subarachnoid space over the vertex of the left frontal lobe. Animals were killed by formalin or glutaraldehyde perfusion 5 min-2 years after injection, and the distribution of ink over the surface of the brain, in 2-mm slices of brain cleared in cedar wood oil, in paraffin sections and by electron microscopy was documented. These investigations showed that carbon particles were distributed diffusely through the interstitial spaces of the white matter whereas they spread selectively along perivascular spaces in the grey matter outlining both arteries and veins and extending to surround capillaries within 1 h. Carbon particles were rapidly ingested by perivascular cells and, to some extent, by meningeal cells surrounding the larger vessels. Very little movement of carbon-labelled perivascular cells and perivascular macrophages was seen after 2 years. Carbon particles entering the subarachnoid space over the vertex of the cerebral hemispheres drained along selected paravascular and subfrontal pathways in the subarachnoid space to the cribriform plate and thence into nasal lymphatics and cervical lymph nodes. These studies demonstrate the diffuse spread of fluidborne tracers through cerebral white matter in the rat, the perivascular spread of tracer in grey matter and the compartmentalised directional flow or tracer through the subarachnoid space to the cribriform plate and nasal lymphatics. Furthermore, particulate matter selectively injected into perivascular spaces in rat grey matter is rapidly and efficiently ingested by perivascular cells.

Animals↗
PubMed1992

Grading of brain tumours. The British experience.

In order to ascertain how widely the Kernohan and WHO numerical grading systems for brain tumours are used in Britain and how uniformly they are applied, a questionnaire was circulated to named neuropathologists in 19 Regional Neuropathology Centres in Britain. Eighty four per cent replied within 10 days. Their replies showed considerable variation in the use of grading systems and revealed that numerical grading was required mainly by clinicians and was not necessarily favoured by pathologists. Although some advantages of a grading system were advanced, it does seem that numerical grading of brain tumours is ill-defined and controversial. Furthermore, the use of historical grading systems may inhibit the incorporation of advances in pathological investigation into the clinical management of patients with brain tumours.

Astrocytoma↗
PubMed1992

Effects of ethanol and various alcoholic beverages on the formation of O6-methyldeoxyguanosine from concurrently administered N-nitrosomethylbenzylamine in rats: a dose-response study.

Consumption of alcoholic beverages has been identified as a major cause of oesophageal cancer in industrialized countries, with an exceptionally high risk associated with apple-based liquors (calvados). In the present study, we have determined the dose--activity relationship of the effects of coincident ethanol on the formation of O6-methyldeoxyguanosine (O6-MEdG) by the oesophageal carcinogen N-nitrosomethylbenzylamine (NMBzA). Male Fischer 344 rats received a single intragastric dose of NMBzA (2.5 mg/kg body wt; 7.4 ml/kg body wt) in tap water containing 0-20% ethanol (v/v). Survival time was 3 h. In controls, concentrations of O6-MEdG were similar in oesophagus, lung and liver (11-14.9 mumol/mol dG). In oesophagus, coincident ethanol increased levels of O6-MEdG from 15.2 mumol/mol (0.1% ethanol) to 46.0 mumol/mol (20%). This increase was dose dependent for 1-20% ethanol; however, low doses produced a larger effect per gram of ethanol than higher doses. In lung, concentrations of O6-MEdG increased from 11 mumol/mol (0.1%) to a plateau value of 24 mumol/mol (greater than or equal to 5%). In nasal mucosa, an increase in O6-MEdG from 3.9 mumol/mol (controls) to 30.7 mumol/mol was observed with 4% ethanol. Effects of ethanol on hepatic DNA methylation were statistically non-significant. Modulation of NMBzA bioactivation by various alcoholic beverages (adjusted to 4% ethanol) was also investigated. Increases in oesophageal O6-MEdG were similar (+50% to +116%) with pear brandy, rice wine (sake), farm-made calvados, gin, Scotch whisky, white wine, Pilsner beer and aqueous ethanol. Significantly higher increases were elicited by commercially distilled calvados (+125%) and red burgundy (+162%). In contrast to its effects at an ethanol content of 4%, farm-made calvados diluted to 20% ethanol produced significantly higher (+200%) increases in oesophageal DNA methylation than aqueous ethanol (+148%). Our results show that ethanol is an effective modulator of nitrosamine bioactivation in vivo at intake levels equivalent to moderate social drinking, and that some alcoholic beverages contain congeners that amplify the effects of ethanol, suggesting that modulation of nitrosamine metabolism by acute ethanol may play a role in the etiology of human cancer.

Alcoholic Beverages↗
PubMed1992

Pathways of fluid drainage from the brain--morphological aspects and immunological significance in rat and man.

There is firm physiological evidence for the lymphatic drainage of interstitial fluid and cerebrospinal fluid from the brains of rats, rabbits and cats. The object of this review, is to describe firstly the morphological aspects of lymphatic drainage pathways from the rat brain and secondly, to explore through scanning and transmission electron microscope techniques, the possibility of similar lymphatic drainage pathways in man. Interstitial and oedema fluid spreads diffusely through the white matter in the rat and appears to drain into the ventricular cerebrospinal fluid. In grey matter, however, tracers pass along perivascular spaces to the surface of the brain and into the cerebrospinal fluid. Paravascular compartments in the subarachnoid space follow the course of major arterial branches to the circle of Willis and thence along the ethmoidal arteries to the cribriform plate of the ethmoid bone. Particulate tracers, such as Indian ink, enter channels in the arachnoid beneath the olfactory bulbs and connect directly with nasal lymphatics through channels which pass through holes in the cribriform plate. Proteins and other solutes may also drain along other cranial nerves. Thus, there is a bulk flow pathway for interstitial and cerebrospinal fluid from the rat brain into cervical lymphatics. In man, it is probable that diffuse interstitial drainage of fluid from the white matter occurs in a similar way to that in the rat. Furthermore, the anatomical pathways exist by which bulk drainage of fluid could occur along perivascular spaces from the grey matter into perivascular spaces of the leptomeningeal arteries and thence into the cerebrospinal fluid (CSF).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A further British case of growth hormone induced Creutzfeldt-Jakob disease.

Transmission of Creutzfeldt-Jakob disease (CJD) from cadaveric growth hormone injections had previously been reported in 7 cases, including one from Britain. As a result, the treatment was abandoned in 1985 and superceded by safer recombinant DNA growth hormone injections. Recent reports now record the number of cases worldwide as 23, but with the incubation period being measured in years, new cases of CJD can still present. We give a detailed report of one of the recent cluster of British cases and aim to highlight the problem to clinicians who may encounter further patients with cadaveric growth hormone induced CJD.

Adult↗
PubMed1991

Ubiquitin-immunoreactive intraneuronal inclusions in amyotrophic lateral sclerosis. Morphology, distribution, and specificity.

Antibodies to ubiquitin have been used to search for evidence of abnormal protein degradation in amyotrophic lateral sclerosis--motor neuron disease (ALS). Anterior horn cell ubiquitin-immunoreactive (IR) inclusions were present in all of 31 ALS cases but in none of 23 neurologically normal and in only 1 of 22 neurologically abnormal controls. These inclusions, which were present in familial and sporadic ALS cases, and in cases with dementia, took the form of dense rounded or irregular ubiquitin-IR cytoplasmic inclusions (dense bodies), or loosely arranged bundles ('skeins') of filamentous-appearing material. The presence of ubiquitin-IR inclusions corresponded to the pattern of selective neuronal vulnerability in ALS, although inclusions in pyramidal neurons of the motor cortex were infrequent and were noted in only a minority of cases. Ubiquitin-IR inclusions were more prevalent than Bunina bodies. The latter were present in 67% of ALS cases but were seldom labelled by antibodies to ubiquitin. Intraneuronal inclusions resembling Lewy bodies were present in 23% of ALS cases and were often identified by antibodies to ubiquitin. We conclude that the presence of ubiquitin-IR inclusions in lower motor neurons represents a characteristic pathological feature of ALS in its various clinical forms. Ubiquitin-IR inclusions in ALS differ from ubiquitinated inclusions in other neuronal degenerations in that they are not readily identified by antibodies to cytoskeletal proteins. They may represent accumulations of altered or abnormal neuronal proteins resistant to degradation via the ubiquitin proteolytic pathway.

Adult↗
PubMed1991

Spindle-cell glioblastoma or gliosarcoma?

'Gliosarcomas' have long been considered to be mixed gliomas and sarcomas. The present study failed to define criteria which clearly delineate 'gliosarcomas' from glioblastoma multiforme and suggests that 'gliosarcomas' should be considered as spindle cell glioblastomas. A total of six cases originally diagnosed as 'gliosarcomas' were compared with four cases of glioblastoma multiforme. No clinical or prognostic features were defined which would clearly separate 'gliosarcomas' from glioblastoma multiforme. Macroscopically, biopsies from 'gliosarcomas' ranged from firm, apparently well-circumscribed tumours to poorly circumscribed lesions with a soft consistency resembling glioblastoma multiforme. Histology revealed a continuous spectrum in which 'gliosarcomas' with large reticulin-rich areas of spindle cells merged with typical glioblastomas containing only small islands of spindle cells and reticulin staining. Immunocytochemistry for glial fibrillary acidic protein (GFAP); S100 protein and alpha-smooth muscle actin (ASMA) showed that the majority of cells in reticulin-poor areas of 'gliosarcoma' and glioblastomas expressed S100 protein and GFAP; many expressed ASMA and some expressed both GFAP and ASMA. Spindle cells in reticulin-rich areas of 'gliosarcomas' and glioblastomas most frequently expressed ASMA but many cells also expressed S100 protein and GFAP; some cells expressed both GFAP and ASMA. The results of this study and a review of the literature suggests that there is a clinical, radiological and pathological continuum with glioblastoma and 'gliosarcoma' at different ends of the spectrum. It is suggested, therefore, that most, if not all, 'gliosarcomas' be redesignated as spindle cell glioblastomas and not be considered as a mixture of glioma and sarcoma.

Actins↗
PubMed1991

Barrier functions of the leptomeninges: a study of normal meninges and meningiomas in tissue culture.

The anatomical arrangement of the pia mater suggests that it may act as a regulatory interface between cerebrospinal fluid and the surface of the brain and between arterioles within the brain and the surrounding neural tissue. However, the functional aspects of such a barrier are difficult to evaluate in vivo. In the present study, the enzymic content and endocytotic capacities of normal leptomeningeal cells in situ and meningioma cells in confluent tissue culture are examined in relation to barrier functions of meningeal cells. Growth of cells in culture was obtained from human fetal and newborn rat leptomeninges and from 9/13 meningiomas. But, in only two meningiomas were the cultured cells characterized as meningeal in origin by using the strict criteria of desmosomes identified by immunocytochemistry or by electron microscopy. These two tumours had high (8-8.7%) Ki-67 labelling indices. Glutamine synthetase activity is present in normal meninges and in meningioma cells in culture; this enzyme together with catechol-O-methyltransferase could play a role in limiting the diffusion of neurotransmitters into brain tissue. A steady rate of endocytosis of carbon particles and fluorescent latex beads, 0.2-1 microns in diameter, was observed in cultured meningioma cells. Such endocytosis was inhibited by cytochalasin B indicating the active participation of intracellular microfilaments. Similar endocytosis has been observed in normal leptomeninges in vivo. The results of this study suggest that meningioma cells in culture reflect the barrier functions of the pia mater and may be used as a model to further investigate the functions of the pia mater.

Animals↗
PubMed1990

The structure of the lamina cribrosa of the human eye: an immunocytochemical and electron microscopical study.

The structure of the lamina cribrosa was studied by histological and immunocytochemical techniques and by scanning and transmission electron microscopy in four eyes removed surgically and in 21 normal eyes obtained from an eye bank. Dissection of the eyes emphasised the relatively fragile links between lamina and sclera. Reticulin staining of the fibrous trabeculae in the posterior (scleral) part of the lamina revealed a structure composed of interweaving skeins of collagen fibres frequently arranged tangentially around the canals, 40-220 microns in diameter, through which optic nerve axons pass. Immunocytochemistry for glial fibrillary acidic protein demonstrated the intimate web that astrocyte processes form around axons within the canals of the lamina and the close association of astrocyte processes and fibrous trabeculae in the posterior part of the lamina. Scanning electron microscopy clearly demonstrated anatomical relationships of the lamina cribrosa and the wide variation in the size of the canals in the lamina. Transmission electron microscopy confirmed the close association of astrocyte processes with axons demonstrated in the immunocytochemical preparations. The results of this study emphasise the complex relationships between astrocytic, neural and fibrous elements in the lamina cribrosa and how more information is required regarding the mechanical and metabolic properties of the astrocyte web and the fibrous trabeculae before the role of the lamina cribrosa in the pathogenesis of nerve damage in glaucoma can be fully assessed.

Adolescent↗
PubMed1990

Protein gene product (PGP) 9.5 as a reliable marker in primitive neuroectodermal tumours--an immunohistochemical study of 21 childhood cases.

A number of antibodies to neural proteins have been used to demonstrate neuronal differentiation in primitive neuroectodermal tumours. One of them is protein gene product (PGP) 9.5, a neuronal protein isolated from brain, whose function is unknown at present. We have studied differentiation in 21 cases of primitive neuroectodermal tumours of the CNS in children. Immunocytochemical staining was performed for such neuronal markers as: PGP 9.5, neuron specific enolase and synaptophysin, a glycosylated protein associated with synaptic vesicles. Positive staining for PGP 9.5 was present in 16 cases (strong staining in 12), for neuron-specific enolase in 16 cases (strong staining in 10) and for synaptophysin in 10 cases (strong staining in six). Both PGP 9.5 and synaptophysin showed a clear staining pattern with less non-specific background than with neuron-specific enolase. Our findings demonstrate the value of using more than one antibody marker in assessing neuronal differentiation in tumours. The high incidence of positive staining with antibody to PGP 9.5 suggests that this is an essential marker in the panel of antibodies used for the identification of primitive neuroectodermal tumours.

Adolescent↗
PubMed1990

Cell proliferation patterns in the diagnosis of astrocytomas, anaplastic astrocytomas and glioblastoma multiforme: a Ki-67 study.

Although astrocytomas, anaplastic astrocytomas and glioblastoma multiforme differ in their clinical courses, histological distinction between these three tumours and between astrocytomas and anaplastic astrocytomas in particular may be unclear on histology alone especially in small biopsies. In the present study, a more objective way of distinguishing between the three types of tumour is sought. Frozen sections from 26 astrocytomas, 26 anaplastic astrocytomas and 38 glioblastomas were stained by an indirect immunoperoxidase technique using the monoclonal antibody Ki-67 which binds to nuclear proteins in the G1, S, G2 and M phases of the cell cycle. The Ki-67 staining was assessed quantitatively through direct observation of the stained sections by the use of a drawing tube attached to a microscope. A minimum of 1000 cells was counted in each case and labelled cells were expressed as a percentage of the total number of cells. These results, when correlated in each case with the histology of the tumour in paraffin sections, showed Ki-67 labelling indices ranging from 0 to 1.9% (mean 0.5% SD +/- 0.54) in astrocytomas, 0.6 to 10.9% (mean 4.1% SD +/- 2.8) in anaplastic astrocytomas and 0.9 to 16.2% (mean 6.4% SD +/- 3.34) in glioblastoma multiforme. The differences in the three types of tumour were statistically significant. The results suggest that Ki-67 staining is a useful addition to the panel of techniques for distinguishing between astrocytomas, anaplastic astrocytomas and glioblastoma multiforme.

Antibodies, Monoclonal↗
PubMed1990

Role of the basement membrane in the regeneration of skeletal muscle.

In many experimental models of skeletal muscle damage and in human muscle disease, empty basement membrane tubes remain following the destruction of muscle fibres. In the present study we test the hypothesis that the empty basement membrane tubes play an essential role in the orientation of regenerating muscle fibres. Two groups of 15 Wistar rats were used. In one group, aqueous barium chloride (BaCl2) solution was injected into the right quadriceps muscle; in the other group, freshly prepared 2% trypsin solution was similarly injected. The different stages of muscle cell necrosis and regeneration were observed by histology, by immunofluorescence using an anti-basement membrane antibody, and by transmission (TEM) and scanning electron microscopy (SEM) in animals killed 1-77 days following injection. Although there was muscle fibre necrosis at sites of BaCl2 injection, empty basement membrane tubes were well preserved. Myoblasts grew along the empty basement membrane tubes and by 77 days, the regenerated muscle fibres at the site of the injection were well oriented. Trypsin not only destroyed muscle fibres but also destroyed the basement membrane tubes; in the early stages of regeneration the myoblasts were disorientated but by 77 days, regeneration was comparable to that seen in the barium chloride injected muscle. The results of this study suggest that preservation of empty basement membrane tubes is not essential for the orientation of regenerating myoblasts in skeletal muscle.

Animals↗
PubMed1990

Stiffman syndrome: a rare paraneoplastic disorder?

An unusual case of the stiffman syndrome, associated with an oat cell carcinoma of the bronchus, is reported. Pathological examination showed that it was due to an encephalomyelitis similar to that seen in paraneoplastic disorders. This suggests that atypical cases of the stiffman syndrome may occasionally be paraneoplastic.

Aged↗
PubMed1990

Interrelationships of the pia mater and the perivascular (Virchow-Robin) spaces in the human cerebrum.

Biopsies of histologically normal adult human cerebral cortex, underlying white matter and overlying leptomeninges were taken from frontal and temporal lobectomy specimens excised during the removal of cerebral tumours. Multiple blocks from 6 patients (aged 18-53 years) were examined by light and transmission electron microscopy. A thin sheath of pia mater cells was found to surround completely arterioles and arteries in the brain, in the subpial space and in the subarachnoid space. Pia mater cells, forming the perivascular sheath, were identified by the presence of desmosomes or small nexus junctions and by continuity with the pia mater itself. The presence of the pial sheath suggests that the perivascular spaces around intracerebral arteries are in direct continuity with the perivascular spaces around subarachnoid arteries. No similar pial sheath was observed around intracerebral or subpial venules. The role of the periarterial spaces, enclosed by the pial sheath, is discussed in relation to the results of physiological experiments suggesting drainage of interstitial fluid from brain tissue into the perivascular pathways along major cerebral arteries in the subarachnoid space. As arterioles in the brain become smaller and lose their smooth muscle coats, the pial sheath becomes incomplete. The anatomical relationships between the pia mater and blood vessels in the human cerebrum is summarised diagrammatically, and a possible role for pial cells as an enzymic barrier protecting the brain from exogenous catecholamines is discussed.

Adolescent↗