O30 Variation in immunosuppressant impact on severe COVID-19 outcome: preliminary results from the COVID-19 Scottish Registry of Autoimmune Rheumatic Diseases (SCAR-19)

Background/Aims 

The novel infectious disease COVID-19 is associated with a wide spectrum of clinical severity amongst the general population. Patients with autoimmune rheumatic diseases (ARD) are more likely to experience serious COVID-19 related events, although risk factors for such outcomes have yet to be established. In particular, the risk profiles of specific ARD therapies are unknown.

Methods 

A Scottish wide registry was rapidly developed in March 2020. Clinical characteristics and outcomes of infected cases were collated across all Scottish health boards, leveraging the Scottish Systemic Vasculitis Network and Scottish Society for Rheumatology. Eligible patients included any adult ARD patients with a confirmed (clinically or PCR) diagnosis of COVID-19. Simple descriptive statistics were employed to evaluate associations between ARD therapies and a serious COVID-19 disease outcome, as defined by a requirement of invasive or non-invasive ventilation, and/or death.

Results 

A total of 69 patients (59% female; mean age 65.6, SD15.5) were recruited to the registry ,92% of which required hospitalisation. Cases were most commonly diagnosed with rheumatoid arthritis (n = 32, 46.4%) followed by spondyloarthritis (n = 19, 27.5%) and systemic vasculitis (n = 9, 13.0%). Anti-TNF therapy (n = 8, 11.6%) and methotrexate (n = 31, 44.9%) were the commonest biologic and conventional disease modifying drug (bDMARD and csDMARD) used respectively. N = 20 (29%) received background corticosteroid therapy (15.9% prednisolone >5mg, 13% prednisolone ≤5mg). A severe outcome was observed in n = 25(31.9%); n = 11 required assisted ventilation and n = 19 died. With the exception of Leflunomide, conventional and biologic DMARDs did not appear to confer a higher risk for severe outcome (table 1). Of note, anti-TNF therapy was associated with a non-serious outcome (p = 0.04) and prednisolone>5mg with a serious outcome (p = 0.08).

Conclusion 

Preliminary data from this Scotland-wide ARD COVID-19 registry evidences variation in the impact of standard ARD therapies on the severity of COVID-19 outcome. In general, background csDMARD and bDMARD use does not appear to be a risk factor for severe outcomes. However, anti-TNF therapy may confer a favourable outcome, while leflunomide and corticosteroids may have the opposite effect. Rheumatologists should be aware of these possible risk factors and continue to contribute to registries to help establish whether these putative signals are clinically relevant.

Disclosure 

M. Karabayas: None. J. Brock: None. M. Rutherford: None. G. Fordyce: None. N. Fluck: None. S. Kardash: None. L. Moran: None. R. Richmond: None. A. Tan: None. J. Sznajd: None. S. Lambie: None. M. Khalid: None. S. Else: None. C.A. Davies: None. M. Duncan: None. J. Mclaren: None. S. Duncan: None. S. Murphy5: None. F. Hasan: None. N. Basu: None.

Cardiorespiratory fitness testing and cardiovascular disease risk in male steelworkers

BACKGROUND

The workplace has been advocated as a setting to perform cardiovascular disease (CVD) risk assessments. These risk assessments usually focus on traditional risk factors rather than cardiorespiratory fitness (CRF) despite established associations between CRF and CVD. The lack of guidance on interpreting health-related CRF values has been suggested as a barrier to utilizing CRF in practice.

AIMS

To assess the merits of CRF testing in the workplace and explore whether a CRF value identified male individuals above the recommended threshold for further clinical investigation.

METHODS

Cross-sectional analysis of male steelworkers from Carmarthenshire, South Wales, UK who completed a workplace-based CVD risk assessment with an added CRF protocol based on heart rate responses (Chester Step Test). Receiver operating characteristic (ROC) analysis was undertaken to explore the possibility of a CRF value to identify individuals at an increased 10-year risk of CVD (QRISK2 ≥ 10%).

RESULTS

There were 81 participants. ROC analysis revealed that a CRF level of 34.5ml/kg/min identified those individuals above the ≥10% QRISK2 threshold with the best sensitivity (0.800) and specificity (0.687) to discriminate against true- and false-positive rates. Further analysis revealed that individuals with either 'Average' or 'Below Average' CRF would be five times more likely to have a 10-year CVD risk above the ≥10% QRISK2 threshold than individuals with an 'Excellent' or 'Good' level of fitness [OR 5.10 (95% CI 1.60-16.3)].

CONCLUSIONS

This study suggests CRF assessments are a useful addition to a workplace CVD assessment and could identify male individuals at increased predicted risk of the condition.

Adiposity has differing associations with incident coronary heart disease and mortality in the Scottish population: cross-sectional surveys with follow-up

OBJECTIVE

Investigation of the association of excess adiposity with three different outcomes: all-cause mortality, coronary heart disease (CHD) mortality and incident CHD.

DESIGN

Cross-sectional surveys linked to hospital admissions and death records.

SUBJECTS

19 329 adults (aged 18-86 years) from a representative sample of the Scottish population.

MEASUREMENTS

Gender-stratified Cox proportional hazards models were used to estimate hazard ratios (HRs) for all-cause mortality, CHD mortality and incident CHD. Separate models incorporating the anthropometric measurements body mass index (BMI), waist circumference (WC) or waist-hip ratio (WHR) were created adjusted for age, year of survey, smoking status and alcohol consumption.

RESULTS

For both genders, BMI-defined obesity (30 kg m(-2)) was not associated with either an increased risk of all-cause mortality or CHD mortality. However, there was an increased risk of incident CHD among the obese men (hazard ratio (HR)=1.78; 95% confidence interval=1.37-2.31) and obese women (HR=1.93; 95% confidence interval=1.44-2.59). There was a similar pattern for WC with regard to the three outcomes; for incident CHD, the HR=1.70 (1.35-2.14) for men and 1.71 (1.28-2.29) for women in the highest WC category (men 102 cm, women 88 cm), synonymous with abdominal obesity. For men, the highest category of WHR (1.0) was associated with an increased risk of all-cause mortality (1.29; 1.04-1.60) and incident CHD (1.55; 1.19-2.01). Among women with a high WHR (0.85) there was an increased risk of all outcomes: all-cause mortality (1.56; 1.26-1.94), CHD mortality (2.49; 1.36-4.56) and incident CHD (1.76; 1.31-2.38).

CONCLUSIONS

In this study excess adiposity was associated with an increased risk of incident CHD but not necessarily death. One possibility is that modern medical intervention has contributed to improved survival of first CHD events. The future health burden of increased obesity levels may manifest as an increase in the prevalence of individuals living with CHD and its consequences.

Expression of osteonectin and matrix Gla protein in scleroderma patients with and without calcinosis

OBJECTIVES

Our aim was to evaluate (i) whether the bone matrix proteins osteonectin and matrix gamma-carboxyglutamic acid protein (MGP) are up-regulated in skin biopsies from patients with systemic sclerosis (SSc) and (ii) whether there is differential expression between patients with and without dermal calcinosis, a distressing and debilitating complication of SSc.

METHODS

Skin punch biopsies were taken from the forearms of 38 SSc patients with the limited cutaneous subtype of SSc [17 without calcinosis (lcSSc) and 21 with calcinosis (lcSScCal)] and from 11 healthy control subjects. Immunohistochemistry was performed with antibodies to osteonectin and MGP. Staining was assessed semiquantitatively in the microvascular endothelium and in dermal fibroblasts. The Kruskal-Wallis one-way ANOVA was used to compare the data between patient groups.

RESULTS

Both lcSSc and lcSScCal groups showed a statistically significant increase in the percentage of microvessels with osteonectin-positive endothelial cells (EC) (especially the lcSScCal group), whereas lcSScCal alone showed an increase in the percentage of microvessels with MGP-positive EC when compared with controls. In both SSc groups, the percentage of osteonectin and MGP-stained fibroblasts was increased in the reticular dermis (for osteonectin this was more marked in the lcSScCal group). In the papillary dermis, the percentage of osteonectin-stained fibroblasts was increased in both SSc groups but the lcSScCal group alone had a higher percentage of MGP-stained fibroblasts.

CONCLUSIONS

When compared with controls, protein expression of osteonectin and MGP was greater in SSc patients generally, and osteonectin expression was significantly higher in EC and fibroblasts of the lcSScCal patients than the lcSSc patients without calcinosis.

The glial cell response to a viral vector in the aged brain

The normal aged brain undergoes pro-inflammatory changes. We investigated the effect of injecting a potential inflammatory stimulus, an adenoviral vector, on the response of microglia and astroglia in the aged brain. Groups of young (4 months) and old (31 months) male C57BL/Icrfat mice received a unilateral injection into the striatum of adenoviral vector encoding the LacZ gene. After 48 h, the mice were killed and the brains analysed for numbers of activated microglia and macrophages using the biotinylated lectin Griffonia simplicifolia as a marker; astroglia were identified by immunohistochemistry for glial fibrillary acidic protein (GFAP). The cell counts were analysed using two-way analysis of variance (anova). Transgene expression was assessed by beta-galactosidase histochemistry. The numbers of activated microglia in the striatum increased in response to the adenovirus in both young [contralateral 19.5 (3.7), ipsilateral 36 (3.0)] and old [contralateral 23.1 (9.6), ipsilateral 40.8 (6.9)] mice (two-way anova; P < 0.0001), but there was no significant difference between the two age groups. There was a significant age-related increase in the number of GFAP-positive astroglia in the uninjected, contralateral striatum [4 months, 2.5 (1.4); 31 months, 29.7 (9.3)] (two-way anova; P < 0.0001). However, there was no difference in response to the adenovirus in both young [contralateral 2.5 (1.4), ipsilateral 3.2 (1.2)] and old [contralateral 29.7 (9.3), ipsilateral 28.9 (8.2)] mice. We conclude that even though it has been argued that the aged brain is in a pro-inflammatory state, under the experimental conditions used in this study, there was no difference in the nature of the immune response between young and old mice of this strain to an adenoviral load.

Characterization of the radical product formed from the reaction of nitric oxide with the spin trap 3,5-dibromo-4-nitrosobenzene sulfonate

Previously, 3,5-dibromo-4-nitrosobenzene sulfonate (DBNBS) has been used in combination with electron paramagnetic resonance (EPR) spectrometry to trap nitric oxide (NO(*)). The reaction between DBNBS and NO(*) yields a radical product which gives rise to an EPR signal consisting of three lines with an A(N) = 0.96 mT, but the structure of this product is unknown. A two-stage high-performance liquid chromatography fractionation was performed to isolate the radical product from the other components in the DBNBS/NO(*) reaction mixture. The fractions containing the radical product were identified by the presence of the three-line EPR signal, and then these fractions were analyzed by negative ion fast atom bombardment-mass spectrometry (FAB-MS). Collectively, the FAB-MS data suggested that the radical product is the monosodium electrostatic complex with the dianion, bis(2,6-dibromo-4-sulfophenyl) nitroxyl. Analysis of the Gaussian and Lorentzian linewidths of the EPR signal suggested that bis(2,6-dibromo-4-sulfophenyl) nitroxyl molecules may group together to form micelles. Further studies also indicated that significant amounts of nitrogen and nitrate were produced during the reaction between DBNBS and NO(*). A reaction scheme consistent with these results is presented.

Oedema and glial cell involvement in the aged mouse brain after permanent focal ischaemia

This study examines the effect of age on oedema and brain swelling, and associated glial cell involvement on the size of the lesion in two models of permanent, focal cerebral ischaemia. Ischaemia was induced in male C57BL/Icrfat mice (4-6 and 26-31-month-old) by middle cerebral artery (MCA) occlusion using either electrocoagulation after craniotomy (MCA/craniotomy), or by an intraluminal filament through the carotid artery (MCA/icf). Twenty-four hours after inducing ischaemia, brain swelling and lesion size were measured in young and aged mice, and cerebral oedema by wet/dry brain weights. Histopathology and immunocytochemistry were performed on a separate set of perfusion fixed brains. The MCA/icf technique produced a significantly larger lesion than MCA/craniotomy in both age groups. The percentage of water taken into the brain was significantly greater after MCA/icf, with aged mice showing the greatest increase. When lesion size was corrected for brain swelling there was no age-related increase in the size of the lesion. The numbers of microglia and astroglia increased significantly in the parietal cortex of aged control animals, and there were qualitative differences in the glial response between the two stroke models. This study emphasizes the importance of age in models of permanent focal ischaemia, with oedema clearly being a significant factor. Differ-ences in the responsiveness of the glial cell population with age may be of fundamental importance in the progress of ischaemic brain damage.

Simultaneous analysis of nitrite, nitrate and the nicotinamide nucleotides by capillary electrophoresis: application to biochemical studies and human extracellular fluids

A simple but rapid capillary electrophoresis method was developed for the measurement of nitrite and nitrate in human extracellular fluids and other aqueous solutions. The capabilities of the method were demonstrated by the measurement of endogenous nitrite and nitrate in plasma and serum samples from healthy volunteers, and serum and synovial fluid samples from rheumatoid arthritis patients. Furthermore, this method was used to simultaneously measure nicotinamide adenine dinucleotide, reduced (NADH), nicotinamide adenine dinucleotide (NAD+), nitrite, and nitrate, when studying the nitrite reductase activity of xanthine oxidase. The stability of nitrite was also investigated and it was found that when whole blood was spiked with nitrite and then processed, the nitrite was more stable in the plasma than in the serum. Our findings may help to explain the variations in basal nitrite concentrations reported in the literature.

The progression and topographic distribution of interleukin-1beta expression after permanent middle cerebral artery occlusion in the rat

The cytokine interleukin-1 (IL-1) has been implicated in the exacerbation of ischemic damage in the brains of rodents. This study has ascertained the cellular localization and chronologic and topographic distribution of pro/mature interleukin-1beta (IL-1beta) protein 0.5, 1, 2, 6, 24, and 48 hours after ischemia by subjecting rats to permanent unilateral occlusion of the middle cerebral artery. Interleukin-1beta was localized immunocytochemically in vibratome sections of perfusion-fixed brains. The cells that expressed IL-1beta had the morphologic features of microglia and macrophages. Interleukin-1beta was first detected 1 hour after occlusion in ipsilateral meningeal macrophage-like cells. By 6 hours, pro/mature IL-1beta-immunoreactive (IL-1(beta)ir) putative microglia were present in the ischemic cerebral cortex, corpus callosum, caudoputamen, and surrounding tissue. By 24 and 48 hours after ischemia, the number and spread of IL-1(beta)ir cells increased greatly, including those resembling activated microglia and macrophages, as the core of the infarct became infiltrated. Interleukin-1(beta)ir cells also were present in apparently undamaged tissue, adjacent to the lesion ipsilaterally, and contralaterally in the cerebral cortex, dorsal corpus callosum, dorsal caudoputamen, and hippocampus. These results support the functional role of IL-1 in ischemic brain damage and reveal a distinct temporal and spatial expression of IL-1beta protein in cells believed to be microglia and macrophages.

An integrated analysis of the progression of cell responses induced by permanent focal middle cerebral artery occlusion in the rat

Defining the chronology and severity of cell damage in an evolving lesion after ischemia is important for understanding the underlying mechanisms in the development of therapeutic intervention. In the present study, we used a combination of histological and immunocytochemical methods to evaluate cell responses from 30 min to 48 h after permanent occlusion of the middle cerebral artery (MCAO) in the rat. Specific immunocytochemical markers clearly revealed acute early responses in neurons (neurofilament protein 200), astrocytes (glial fibrillary acidic protein), and microglia/macrophages (OX-42 and ED-1) such as enlarged, convoluted neuronal processes, and disintegration of glia. Progressive topographic changes in the developing lesion, pinpointed by immunolabeling, indicated the severity and extension of the cell damage. Proliferation and hypertrophy of astrocytes and microglia around the infarct, and contralaterally, occurred 24-48 h after MCAO and coincided with mass necrosis and infiltration of neutrophils and macrophages into the core. These observations corroborate the suggestion that the inflammatory process is involved in the progression of the infarct.

Nutrition in adults with cystic fibrosis

Improved survival has been associated with better nutritional status in patients with cystic fibrosis (CF). In this study we examined the relationship between nutritional state and other measures of clinical severity in adult patients with CF, attending a regional centre. Eighty-one patients (median age 21 years) were studied. Patients with CF were significantly under weight, compared to healthy individuals but were of similar height. Measurements of lung function, FEV1 and FVC were significantly related to body mass index. Lung function was poorer in patients with chronic pseudomonal infection but body weight and body mass index were not significantly different compared to those without such infection. In 53 patients who were alive 4 years later, FEV1 had declined by -10.5 (2.1)% (P < 0.001) but there was no significant change in body weight 1.5 (6.5) kgs. In 23 patients who died or had lung transplantation the change from 1994 to the date of death or transplantation the FEV1 was reduced by -7.9 (11.2)% (P = 0.004) and body weight -2.8 (4.4) kgs (P < 0.01). In 12 patients who had supplemental enteral feeding, the median increase in body weight was 7|kgs over a period of 12 months. This study confirms that young adult patients with CF are significantly under weight and declining health is associated with significant weight loss. In patients with severe malnutrition significant improvement can be achieved by enteral feeding.

Inspiratory muscle function and body composition in cystic fibrosis

Loss of body mass, which occurs in the later stages of cystic fibrosis (CF), probably affects all body compartments. We hypothesized that loss of skeletal muscle mass would include inspiratory muscles and impair their function. To test this, we determined the effect of body mass index (BMI) and lean body mass (LBM) depletion on handgrip (HG) force and inspiratory muscle function (IMF). The maximum inspiratory pressure (MIP) and the sustained maximum inspiratory pressure (SMIP) were measured with a computerized system. The relationship of IMF and reduced BMI to survival was studied in 49 patients, and a further 25 patients were studied to define the link between IMF and LBM. LBM was assessed by anthropometry. In the survival study a BMI < 20 kg/m2 was associated with a low SMIP (p < 0.001) and reduced survival, whereas MIP was relatively preserved. In the cross-sectional study SMIP (p < 0.001), MIP (p < 0.01), and HG (p < 0.01) were all reduced in the low LBM group, but not when related to total LBM. C-reactive protein and LBM were inversely related (r = -0.71, p < 0.01). Impaired IMF was chiefly a loss of sustained muscle contraction secondary to a reduced skeletal muscle mass, which may be related to pulmonary inflammation.

Information for management--the extent of information management in the acute care hospital sector

The article explores the contributions of information and information technology to health care management by means of a study into current information use in a small acute care hospital and the preparations for new general practitioner purchasing systems. The findings highlight the interdependency between manual and computer systems and key departments in the hospital. With increased emphasis on primary health care, there is a greater need for information sharing between the hospital and general practitioners. Provision of information itself becomes a factor in determining service quality. Information systems are therefore emerging as an element in gaining competitive advantage in hospitals in the United Kingdom.

A prodigious information systems failure

The article reports a case study in the conception and implementation of a regional information systems project in a Regional Health Authority in England in the 1980s. The project was technically ambitious and involved far-reaching organizational changes throughout the region. The project failed, after considerable expenditure, because support in the region dwindled. With reference to the context of changing management practice in the National Health Service in the 1980s, the project is assessed in the light of its technocratic focus and its effects on the organization, including implicit changes in power relationships.

Is the "preamyloid" of diffuse plaques in Alzheimer's disease really nonfibrillar?

Several papers have described an 'amorphous' component of the amyloid in diffuse plaques and it has been suggested that this is 'preamyloid,' which is not organized into fibrils. Because most of the studies have been performed on autopsy tissue it was the purpose of this study to compare the ultrastructure of diffuse amyloid deposits in well preserved Alzheimer's disease biopsy specimens with autopsy tissues from patients with Alzheimer's disease and Down's syndrome. A postembedding immunogold technique with anti-beta/A4 protein demonstrated gold particles exclusively on extracellular amyloid fibrils in both biopsy and autopsy brains. We have presented evidence that suggests the claim for the existence of an amorphous component within the beta/A4 protein-positive material is unconvincing.

A quantitative assessment of somatostatin-like and neuropeptide Y-like immunostained cells in the frontal and temporal cortex of patients with Alzheimer's disease

Immunocytochemical studies utilizing radioimmunoassay and morphological techniques have provided conflicting evidence for the involvement of somatostatin and neuropeptide Y in Alzheimer's disease (AD). However, previous investigators have not considered the effects of cortical atrophy in AD tissue on their findings. This study reports the numbers of somatostatin-like (SLI) and neuropeptide Y-like immunoreactive (NPYLI) neuronal perikarya and the length of SLI and NPYLI immunoreactive fibres, with appropriate corrections for atrophy in 6 control and 6 AD cases. There were significantly fewer SLI neurones in AD in layers II + III combined from the temporal cortex, and fewer NPYLI neurones in layers V + VI in both frontal and temporal cortices. Using a randomized method to quantify immunostained fibre length in the neuropil, an analysis of variance revealed no significant differences in the mean SLI or NPYLI fibre length per cortical strip between control and AD groups in frontal or temporal cortex. However, using a second measure of fibre length by tracing the fibres attached to consecutive immunostained perikarya, there were significant reductions in the AD brains in the mean fibre length per cell in layers V + VI for SLI in the temporal cortex, and for NPYLI in the frontal cortex. This reduction in fibre length per individual cell was presumably masked by the large variation in the fibre length found between cases using the randomized approach. It was concluded that in order to evaluate the involvement of these neuropeptides in AD from any measurements of concentration, it is essential to include some compensation for the extent of cortical atrophy that occurs with the disease.

Reversal of midazolam sedation with flumazenil following conservative dentistry

The purpose of this double-blind randomized study was to assess recovery of mental function following reversal of midazolam-induced sedation with the specific antagonist flumazenil (R015-1788) or placebo following conservative dental procedures. Recovery was assessed using choice reaction time and critical flicker fusion threshold, both objective tests of psychomotor function; linear analogue sedation scores and simple memory tests. Assessments were repeated up to 3 h after administration of flumazenil or placebo to discover whether recovery was sustained or whether resedation occurred due to the short duration of action of flumazenil. Flumazenil in doses from 0.5 to 1.0 mg rapidly reversed the sedative and amnesic effects of a mean dose of 8.2 mg of midazolam without apparent evidence of subsequent resedation. Since recovery of mental function in the control group had ordinarily occurred 45 min after administration of placebo, routine reversal of midazolam sedation with flumazenil cannot be justified. Nevertheless, in cases of undue sedation persisting after dental treatment, flumazenil may be used with minimal risk of resedation occurring.

A morphological analysis of senile plaques in the brains of non-demented persons of different ages using silver, immunocytochemical and lectin histochemical staining techniques

The prevalence and severity of senile plaque (SP) formation was investigated in the cerebral cortex, hippocampus and amygdala of 60 non-demented individuals of age range 6-84 years, using immunocytochemical (anti-A4 amyloid, anti-PHF protein), lectin histochemical (Con A binding) and silver (Methenamine (MS) and Palmgren), staining methods. By at least one of these methods, 18 patients showed the presence of SP within one or more of these brain regions; 15 of these patients were over 60 years of age. Comparisons between each staining method showed that, in the hippocampus and amygdala all five methods detected the presence and number of SP equally well, whereas, in the cerebral cortex, MS and anti-A4 staining demonstrated more SP in a greater number of patients than did either Con A or Palmgren silver and anti-PHF staining. The additional SP detected by these former two staining methods contained diffuse deposits of amyloid (A4) protein, and sometimes also large clumps of Con A positive material, but no neurites as detected by Palmgren or anti-PHF staining. Such SP closely resemble those seen in the cerebral cortex of young patients with Down's syndrome, and which are thought to be an early form of SP. The relationship between the pathological changes in these non-demented patients and a possible diagnosis of early Alzheimer's disease is discussed.

Immunocytochemical profile of neurofibrillary tangles in Down's syndrome patients of different ages

Brains were obtained at autopsy from 24 patients with Down's syndrome, ranging in age from 13 to 71 years. Neurofibrillary tangle containing neurones of the hippocampus were stained using a Palmgren silver method and immunocytochemically (PAP) using antisera to paired helical filament protein, human tau protein and ubiquitin, as primary antibody. Counts of cells stained by each method were compared. In patients under 50 years of age, in whom only a limited number of tangle bearing cells were present, the number of profiles visualized with silver, anti-paired helical filament and anti-tau methods were similar. However, in patients over 50 years of age (and in certain of those under 50), in whom numerous tangles were present, the number of cell profiles visualized with silver and anti-paired helical filament methods were still similar though anti-tau detected fewer positive cells. This was because of the increased presence, in such patients, of extracellular tangles which had "lost" anti-tau immunoreactivity. Such data suggest that although tau protein forms a major antigenic determinant of neurofibrillary tangles in Down's syndrome (as it does in Alzheimer's disease) this protein may only decorate the basic paired helical filament protein skeleton, and is removed by macrophagic activity upon neuronal death. In all patients, anti-ubiquitin revealed fewer tangles than any other method. It is possible that ubiquitin may be present only transiently, within tangles perhaps following initial formation and lasting only as long as the normal protein degradation processes remain viable within the diseased neurone.

An analysis of the morphology of senile plaques in Down's syndrome patients of different ages using immunocytochemical and lectin histochemical techniques

The morphology of the senile plaque (SP), within the hippocampus and the temporal cortex, has been examined in 21 patients with Down's syndrome (DS), dying between the ages of 13 and 65 years, using immunocytochemical and lectin histochemical methods, as well as with a conventional silver staining technique. The earliest changes detectable within these areas of brain in the younger patients involved a fine diffuse deposition of amyloid (A4) protein and a uniform granular accumulation of an oligosaccharide recognized by the lectin from Canavalia ensiformis (ConA). At this stage, these 'pre-plaque' areas are unrecognizable using silver staining. Later the conventional SP morphology becomes apparent; the A4 protein aggregates into the usual plaque core and neurites appear with silver staining. The fine ConA positive material concentrates into large clumps and becomes recognizable by other lectins such as PSA, WGA and ePHA, which bind to mannose containing structures in an increasingly complex form. It is suggested that the development of the pathological changes of Alzheimer's disease, in patients with DS (and also in AD itself) involves a primary deposition of amyloid protein in conjunction with the accumulation of an as yet unidentified oligosaccharide. These changes precede the neuronal response that is characterized by the formation of neurites and the accumulation of neurofibrillary tangles that ultimately leads to cell death.

Incidence of arrhythmias in dental anaesthesia: a cross-over comparison of halothane and isoflurane

Fifty patients received halothane anaesthesia during the surgical removal of 3rd molars from one side of the mouth and isoflurane during extractions on the other. Degree of surgical difficulty was matched, and end-tidal PCO2 did not differ significantly between sides. A significantly higher incidence of arrhythmias occurred during halothane, compared with isoflurane, anaesthesia. This difference occurred primarily when halothane was given for the first operated side. A clinically important feature of the stability of cardiac rhythm during isoflurane anaesthesia was demonstrated--when frequent ectopic beats occur during halothane anaesthesia, a significant decrease in the rate of premature contractions occurs within 3 min of discontinuing halothane and introducing isoflurane.

A quantitative morphometric analysis of the neuronal and synaptic content of the frontal and temporal cortex in patients with Alzheimer's disease

A quantitative morphometric analysis was used to estimate neurone and synapse densities in cerebral cortical biopsy tissues from patients with dementia under 65 years of age and pathologically verified as suffering from Alzheimer's disease. Estimates of the numerical density of neurones and synapses were made in layers II-III and V of both frontal and temporal cortex. A greater loss of synapses than that of neurones was found in Alzheimer's disease, amounting to a minimum (uncorrected for atrophy) of 25% in layers II-III and 36% in layer V of the temporal cortex, and 27% in layer V of the frontal cortex. Values of synapse to neurone ratio also demonstrated this greater loss of synapses, there being on average 38% fewer synapses associated with each surviving neurone in layers II-III of the temporal cortex, 30% fewer in layer V, and a deficit of 14% in layer V of the frontal cortex. It is concluded that a major loss of synapses occurred in this group of patients with Alzheimer's disease, probably at an early stage of the disease, and that the loss is likely to form a fundamental part of the pathological process that underlies the cortical damage of this condition.

Glycogen accumulations in the cerebral cortex in Alzheimer's disease

The fine structure of granular glycogen bodies (GGB) within the grey matter of the temporal cortex of 11 patients with Alzheimer's disease is described. GGB measure up to 50 microns in diameter and consist of densely packed alpha or beta glycogen granules (never both), neither of which are membrane bound. They were noted in axons, both myelinated and unmyelinated (sometimes close to the dystrophic neurites of senile plaques), and also in other processes of indeterminate origin. Their appearance may relate to disturbances of axonal transport resulting from damage to terminals within evolving senile plaques.

An ultrastructural analysis of the effects of accumulation of neurofibrillary tangle in pyramidal neurons of the cerebral cortex in Alzheimer's disease

Quantitative morphometric (stereological) methods have been used to assess the effects of accumulation of neurofibrillary material on the fine structure of pyramidal cells in biopsy specimens of temporal cortex from nine patients with Alzheimer's disease. When compared with non-tangled cells from the same patients, tangled cells show an increase in total area of cytoplasm due to the accumulation of tangle and a reduction in the area of the nucleus; the area proportion of the cell body occupied by total cytoplasm, therefore, increases whereas that of the nucleus decreases. Within the total cytoplasm, nucleolar and mitochondrial areas are maintained, but that of lipofuscin is increased, though all are increased when expressed as a proportion of the useful cytoplasm alone (i.e. total cytoplasmic area minus area occupied by tangle). Measures of the amount of rough endoplasmic reticulum and ribosomes are decreased overall in tangled cells, though when related to useful cytoplasm alone such measures approach non-tangled cell values. Measures of smooth endoplasmic reticulum are unaltered throughout. When related to the amount of tangle within cells it was found that the most heavily tangled cells retain 28% of useful cytoplasm, 72% of the nuclear area, 50% of the rough endoplasmic reticulum and 27% of ribosomes present within least tangled and non-tangled cells. By contrast, mitochondrial area is maintained and that of lipofuscin increased. The capacity for protein synthesis in tangled cells appears, therefore, to be progressively decreased with accumulation of tangle, whereas that for oxidative metabolism is maintained and lysosomal activity, perhaps, increased. Neurofibrillary tangle formation and accumulation may, therefore, lead to the eventual death of neurons and be the major cause of nerve cell loss in Alzheimer's disease.

A quantitative study of the ultrastructure of pyramidal neurons of the cerebral cortex in Alzheimer's disease in relationship to the degree of dementia

Quantitative morphometric (stereological) methods have been used to measure the number or amount of organelles in pyramidal nerve cells, unaffected by neurofibrillary degeneration, in biopsy specimens of temporal cortex from 11 patients with Alzheimer's disease, and to relate these to the degree of dementia, as measured by psychometric testing. Only areal proportion (AA) and surface area (SA) of rough endoplasmic reticulum were significantly reduced in line with the severity of the degree of dementia. It is suggested that these changes reflect a progressively diminishing requirement for packaging and transport of replacement proteins, particularly in relation to neurotransmitter metabolism in nerve terminals following the loss of synapses which we have shown to occur in these patients.

Effects of differential environments on the cerebral anatomy of rats as a function of previous and subsequent housing conditions

After 1 month in enriched or impoverished environments, groups of rats were housed for an additional month in either the same or the opposite environment. The cross-over design allowed us to see whether or not the cerebral effects of differential environments are modified by subsequent housing conditions, and also whether or not such effects might be influenced by previous experience. Differential housing for 1 month was associated with significant alterations in the weight and length of the cerebrum, the thickness of the occipital cortex, and the relative number of neurons and oligodendrocytes, and no change in the ratio of astrocytes to neurons. The effects of enrichment were not reduced in animals that were previously impoverished. When impoverishment followed enrichment, certain effects appeared to diminish, notably, the increase in cortical thickness. Other effects, however, such as the increase in the ratio of oligodendrocytes to neurons, were very stable. The gross cerebral alterations associated with differential housing did not differ significantly after 2 as opposed to 1 month's exposure, but the effects on neuronal density and the ratio of oligodendrocytes to neurons in layers V and VI of the cortex were, paradoxically, significantly smaller with the longer duration. We suggest that this decrease is due to the continuation of processes induced in the first month of differential experience rather than to their dissipation.

The comparative effects of early-life undernutrition and subsequent differential environments on the dendritic branching of pyramidal cells in rat visual cortex

Male rats were either undernourished or fed normally from birth to day 21, after which time food was made freely available. At 1 month of age littermate pairs from both nutritional groups were housed in either enriched or impoverished conditions for 30 days and then killed for brain measurements. Significant deficits due to undernutrition were observed in the weight and size of the cerebrum, but not in the thickness or area of the visual cortex. Although there were large differences of between 21 and 39% in the number of higher-order basal dendrites of layers II and III pyramidal cells, and of about 19% in the distal ring intersections, none except the fourth-order branches and intersections at 100 micron from the cell body approached statistical significance. Changes in cerebral weight and size also occurred as a result of differential housing, with the enriched rats showing increased values relative to their impoverished littermates. In contrast to the nutritional treatment, differential housing significantly affected cortical thickness and area, as well as basal dendritic branching of the pyramidal cells. Enriched rats had relative increases of 26% in the number of fifth-order branches and 45-80% in the number of distal ring intersections.

The separate and combined effects of early undernutrition and environmental complexity at different ages on cerebral measures in rats

Rats were either undernourished or fed normally during the suckling period, then at 1 and 5 months of age littermates were housed in enriched or impoverished environments for 30 days. The undernutrition caused lasting reductions in the weight and size of the cerebrum and in parameters of the hippocampus, but significant deficits were not observed in the thickness and area of the occipital cortex. Differential housing differed from early undernutrition in that its largest effects were on cortical parameters, but the effects of the two conditions did partly overlap. This meant that some nutritionally induced deficits could be modified later by manipulating environmental complexity. The cerebral response of the previously undernourished rats to differential environments was not distinguishable from that of well-fed controls on the basis of the gross anatomical changes that were measured. Furthermore, no significant differences were found between the environmental effects in young and mature rats, although the latter's response tended to be somewhat less for most parameters.

Effects of undernutrition at different ages early in life and later environmental complexity on parameters of the cerebrum and hippocampus in rats

Nutritional deprivation at different stages of development in rats was shown to cause reductions in some parameters of the cerebrum that could not be reversed by an extended period of adequate feeding. The deficits varied in magnitude, depending on whether undernutrition occurred during the suckling period alone or was combined with additional deprivation either before birth or after weaning. Whereas the weight, length, and width of the cerebrum were affected significantly by undernutrition at every age, effects on the thickness of the cortex and hippocampus were associated only with the combined pre- and postnatal deprivation. The deficits in weight, length, and cortical thickness could be modified later by housing in enriched and impoverished environments for 30 days. The previously undernourished rats responded similarly to environmental complexity regardless of the age at which they had been deprived, and their responses did not differ significantly from those of well fed controls. The degree to which enrichment can be said to have reduced deficits arising from undernutrition depends on the relative size of the nutritional and environmental effects on the particular parameters in question and on the choice of a "normal' baseline against which to assess recovery.

The effects of early-life undernutrition and subsequent environment on morphological parameters of the rat brain

The investigation examines the extent to which lasting effects of early-life undernutrition on the brain of rats can be modified by manipulating the amount of environmental stimulation later. Infant rats were undernourished during the vulnerable brain growth spurt in the lactation period; then after two months of unrestricted feeding, they were placed in enriched or impoverished environments. Measurements of the forebrain, posterior cerebral cortex and hippocampus showed that neither undernutrition nor environmental stimulation affected the brain uniformly and that some parameters were more susceptible to one condition than the other. Where nutritional and environmental conditions affected the same anatomical dimensions, their combined effects appeared to be additive rather than synergistic.

A stereological analysis of the cerebellar granule and Purkinje cells of 30-day-old and adult rats undernourished during early postnatal life

Male rats undernourished from birth to 30 days of age were nutritionally rehabilitated till 160 days of age. Quantitative stereological procedures at the light microscope level were used to estimate, among other things, the numerical densities of cerebellar granule and Purkinje cells on a "per unit volume of cortex" basis. These were subsequently used to calculate granule-to-Purkinje cell ratios. The 30-day-old undernourished rats had a mean +/- S.E. of 290 +/- 27 granule cells for every Purkinje cell present, compared to 395 +/- 34 for the controls. This was a deficit of about 27% (p < 0.05). At 160 days of age, the previously undernourished rats still showed a persisting deficit of about 25% (p < 0.05) in this ratio, despite the lengthy nutritional rehabilitation. There were no statistically significant age-related changes in this ratio. The numerical density of Purkinje cells, but not that of granule cells, was significantly greater in the previously undernourished rats than in controls, for both age groups, Increasing age caused a fall in the numerical density of both cell types. Granule and Purkinje cell nuclear diameters were unaffected by nutrition. However, Purkinje cell nuclei decreased in size by between 7%--13% with increasing age. These results indicate that undernutrition during early life can cause a permanent distortion of the relative number of the various cell types in the cerebellum.

Synapse-to-neuron ratios of the frontal and cerebellar cortex of 30-day-old and adult rats undernourished during early postnatal life

Male rats undernourished from birth to 30 days were nutritionally rehabilitated till 160 days of age. Quantitative stereological procedures at the light and electron microscopical levels were employed to estimate, among other things, the synapse-to-neuron ratios in the frontal cortex and granular layer of the cerebellum. In the frontal cortex, the 30-day-old undernourished rat had a mean +/- SE of about 14,020 +/- 1,540 synapses-per-neuron compared with 22,270 +/- 3,250 for the controls. This was a deficit of 37% (p < 0.05). By 160 days of age the previously undernourished rats showed no statistically significant deficit in this ratio compared with controls (11,800 +/- 690 and 13,360 +/- 1,110 respectively, p > 0.1). This was due mainly to a fall in the synapse-to-neuron ratio with age. A much larger fall in the ratio occurred in the control than in the previously undernourished group. In the granular layer of the cerebellum the 30-day-old undernourished rats had 341 +/- 17 synapses-per-neuron compared with 495 +/- 25 for the controls. This was a deficit of 31% (p < 0.01). By 160 days of age the previously undernourished rats again showed no statistically significant deficit in this ratio compared with controls (627 +/- 56 and 688 +/- 38, respectively (p > 0.1). These results show that the previously undernourished rats are capable of at least some (if not complete) "catch-up" with regard to the synapse-to-neuron ratio.

Deficits in synapse-to-neuron ratio due to early undernutrition show evidence of catch-up in later life

30-day-old rats undernourished from birth are known to have large deficits in the synapse-to-neuron ratio in certain brain regions. It has not been possible to demonstrate any statistically significant deficits in this ratio in animals undernourished from birth to 30 days but then provided with an ad libitum amount of food til 6 months of age.

Sensory projections from the wind-sensitive head hairs of the locust Schistocerca gregaria. Distribution in the central nervous system

The neurones from the wind-sensitive hairs on the locust head have been filled with cobalt chloride and intensified with silver. All the neurones project through the brain to the suboesophageal ganglion, some continue to the prothoracic ganglion and a few as far as the mesothoracic ganglion. Three different types of projection are described and a regrouping is proposed of Weis-Fogh's five hair fields into three areas. The distribution of the neurones from these areas is described in relation to other structures in the ganglion and is discussed in relation to the function of the hair fields in stability control and grooming.

A stereological analysis of the neuronal and synaptic content of the frontal and cerebellar cortex of weanling rats undernourished from birth

The frontal cortex and granular layer of the cerebellum have been examined in 30-day-old rats undernourished from birth. Quantitative stereological procedures at the light microscopical level have been used to estimate the volume proportion and numerical densities of neuronal nuclei. Similar methods at the electron microscopical level were employed to calculate the numerical densities of synapses. Hence, synapse-to-neuron ratios have been calculated in these brain regions. In the frontal cortex, the undernourished group of rats showed a 37% deficit (P less than 0.05) in the synapse-to-neuron ratio. This was due to a combination of an increase in the numberical density of neurons and a decrease in the numerical density of synapses, although, individually, neither of these reached statistical significance at the 5% level. In the granular layer of the cerebellum there was a 31% (P less than 0.01) deficit in the synapse-to-neuron ratio. This was a function of the reduced numerical density of synapses, with no difference in the numerical density of granule cells between groups. For the frontal cortex, the volume proportion of neuronal nuclei was significantly greater in the undernourished group of rats. There were no significant differences between control and undernourished rats in the volume of the 'forebrain' occupied by cortex. The mean diameters of neuronal nuclei and synaptic discs did not differ in any given region between treatment groups. These observations are discussed in context with the previously published results on synapses and neurons in undernourished animals.