Lentigo maligna: a review

Lentigo maligna (LM) is a melanoma in situ with distinct clinical features and histology. It commonly affects men after the sixth decade of life. Incidence rates of LM have increased based on early 21st century data from different countries; however, data are suboptimal. Data from England show a plateauing crude incidence between 2013 and 2019. By comparison, invasive melanoma and other types of melanoma in situ commonly appears in younger age groups (median age 58 and 67 years old, respectively) and incidence is rising. The most important risk factors for LM include fair skin and cumulative ultraviolet solar radiation exposure. Although LM is limited to the epidermis and connected skin adnexa, it may progress to invasive LM melanoma. The reported rate of malignant progression varies, reflecting a challenge for LM epidemiology research as often lesions are removed on diagnosis. LM poses a challenge in diagnosis and management. Although it can be diagnosed clinically or dermoscopically, histopathological assessment of biopsied skin tissue remains the gold standard. Reflectance confocal microscopy allows for better appreciation of the complexity of LM at a cellular level, often progressing beyond clinical margins. Management of LM may involve Mohs micrographic surgery or excision, although recurrence may occur even with 5 mm clinical margins. Imiquimod cream may be effective, but incomplete treatment and recurrence has been reported. Conservative management with observation or radiotherapy may be used in selected patients' cases. Five-year net survival rates are excellent. This paper reviews the natural history, epidemiology, aetiology, pathogenesis, diagnosis and management of LM.

Trends in incidence, treatment and survival of Merkel cell carcinoma in England 2004-2018: a cohort study

BACKGROUND

Merkel cell carcinoma (MCC) is a rare tumour with neuroendocrine differentiation and high associated mortality. Studies that describe the epidemiology of MCC are often limited by small sample size, short duration of follow-up, absence of nationwide data and paucity of data on different risk factors.

OBJECTIVES

To determine the incidence, demographics and survival for MCC in England between 2004 and 2018.

METHODS

This national retrospective cohort study identified all cases of MCC in England from 2004 to 2018 using national population-based data from the National Disease Registration Service. Crude counts, European age-standardized incidence rates (EASRs) and joinpoint analysis were conducted. Patient demographics and treatments received were described. Multivariable Cox regression analysis was used to study risk factors for MCC-specific mortality, by including a priori defined demographic factors, tumour characteristics and immunosuppression. Treatment data were not included in the Cox regression analysis.

RESULTS

A total of 3775 MCC tumours were registered. The median age at diagnosis was 81 years (interquartile range 74-87). Overall, 96·6% of patients identified as White ethnicity, and 8·3% of patients were immunosuppressed. The most common site was the face (27·4%). Patients most often presented with stage one disease (22·8%); however, stage was unknown in 31·0%. In total, 80·7% of patients underwent surgical excision, 43·5% radiotherapy and 9·2% systemic therapy. The EASR increased from 0·43 per 100 000 person-years (PYs) to 0·65 per 100 000 person-years between 2004 and 2018, representing a significant annual percentage change of 3·9%. The EASR was greater in men than in women for all years, with an overall male-to-female ratio of 1·41 : 1. The highest EASR was in South West England. Five-year disease-specific survival was 65·6% [95% confidence interval (CI) 63·8-67·4], with a median follow-up of 767 days. MCC-specific mortality increased with age [hazard ratio (HR) 1·02, 95% CI 1·02-1·03], deprivation (HR 1·43, 95% CI 1·16-1·76), immunosuppression (HR 2·80, 95% CI 2·34-3·34) and stage at diagnosis (HR 8·24, 95% CI 5·84-11·6).

CONCLUSIONS

This study presents the largest national MCC dataset in Europe, and the most complete reporting of MCC incidence and survival ever published. With the EASR of MCC increasing and high associated mortality, this study encourages further research into the pathology, diagnosis and therapeutic options for MCC to support management guidelines.

White plaques on the vulva

We report a 59-year-old woman presenting with vulval white plaques on a background of psoriasis and chronic cutaneous lupus erythematosus, and discuss the histology, diagnosis and treatment options.

An Overview of Uncommon Cutaneous Malignancies, Including Skin Appendageal (Adnexal) Tumours and Sarcomas

A standardised classification of malignant skin appendageal (adnexal) tumours and sarcomas is required for improved patient management and prognosis. This has been hindered by considerable morphological variation both within and between tumour types, the use of many synonyms for the same tumour types and variation in classification between pathologists. This update uses the improved classification in the 2018 WHO classification of skin tumours as the basis to discuss malignant skin appendageal tumours, sarcomas and cutaneous metastases that regularly present to skin cancer clinicians, multidisciplinary skin cancer teams and tumour boards, with current evidence for management, where appropriate.

Desquamative interstitial pneumonia, respiratory bronchiolitis and their relationship to smoking

AIMS

Respiratory bronchiolitis (RB) and desquamative interstitial pneumonia (DIP) are closely associated histological patterns of interstitial pneumonia, although there are no studies on the extent of individual histological parameters. Furthermore, the term smoking related-interstitial lung disease (SR-ILD) has been proposed as a term to encompass patients with both these histological patterns who give a history of smoking, though it is not well defined how this term relates to historical cases of DIP. The aim of this study was to compare histological parameters in cases of DIP and RB and then to review in detail clinical, imaging and histological data for DIP in relation to a history of smoking.

METHODS AND RESULTS

Forty-nine cases were reviewed, 24 with RB and 25 with DIP; five cases of DIP were re-classified as RB on review due to bronchocentricity of the infiltrate. There was a significantly greater extent of interstitial fibrosis (P = 0.02), lymphoid follicles (P < 0.001) and eosinophilic infiltration (P < 0.0001) in patients with DIP compared with RB. In addition, the extents of these three parameters were significantly interrelated. Patients with DIP had a lower incidence of smoking (60%) when compared with patients with RB-ILD (93%) (P < 0.005). Further analysis of smokers versus never-smokers with DIP showed no difference in histological parameters, extent of haemosiderin deposition or the number of CD1a+ macrophages between the two groups, nor were there any differences in clinical data to suggest other aetiologies. Follow-up high-resolution computed tomography data from patients with DIP suggested that a pattern of fibrotic non-specific interstitial pneumonia (NSIP) may develop in the long term in both smokers and never-smokers.

CONCLUSION

There are significant differences in the extent of interstitial fibrosis, lymphoid follicles and eosinophilic infiltration between DIP and RB, as well as a much lower incidence of smoking in patients with DIP. Whether the lower reported incidence of smoking in DIP reflects referral bias or conservatism in giving a history of smoking remains uncertain, as neither histological parameters nor clinical data indicate a difference between smokers and never-smokers with DIP. Nevertheless, some cases of DIP are likely to remain idiopathic and unrelated to RB, though still have a good prognosis. Furthermore, they may evolve into a pattern resembling fibrotic NSIP. Therefore, whilst SR-ILD is appropriate in the correct clinical setting, the distinction between the histological patterns of RB and DIP remains appropriate.

TTF-1 expression is specific for lung primary in typical and atypical carcinoids: TTF-1-positive carcinoids are predominantly in peripheral location

Thyroid transcription factor (TTF)-1 expression in neuroendocrine tumors (NETs) has not been studied as widely as that in non-NETs, with the exception of small cell carcinomas, in which TTF-1 is highly sensitive but not specific for a primary lung tumor. The reported incidence of TTF-1 expression in pulmonary carcinoids has also been highly variable in the literature. To evaluate the expression of TTF-1 in NETs and potential value of TTF-1 in distinguishing pulmonary NETs from those of extrapulmonary origin, we performed an immunohistochemical study by using semiquantitative analysis on formalin-fixed, paraffin-embedded sections from 111 NETs, including 80 pulmonary (11 carcinoid tumorlets [TLs] or foci of neuroendocrine cell hyperplasia [NEH], 36 typical carcinoids [TCs], 17 atypical carcinoids [ACs], 16 large cell neuroendocrine carcinomas [LCNECs]), 13 thymic (3 TCs, 8 ACs, 2 LCNECs), 17 gastrointestinal or pancreatic (13 TCs, 4 ACs), and 1 ovarian (LCNEC). Pulmonary carcinoids were subdivided into those with central and those with peripheral location. TTF-1 positivity was seen exclusively in pulmonary NETs and was significantly higher in NEH or TLs (72.7%) than in TCs (27.8%), ACs (29.4%), and LCNECs (37.5%; P = 0.03). All extrapulmonary NETs were uniformly negative for TTF-1 staining. Interestingly, 12 of 14 TTF-1-positive pulmonary TCs and ACs had a peripheral location with spindle cell morphology, as did all cases of TL, a purported precursor of peripheral carcinoids. In conclusion, TTF-1 expression was 100% specific, though not so sensitive, for the lung primary in TCs and ACs and possibly also in LCNECs. Prevalent TTF-1 positivity in TLs and peripheral carcinoids suggest that they may be histogenetically distinct from the central carcinoids, which are typically composed of TTF-1-negative, more rounded cells.

Formation of involatile methylantimony species by Clostridium spp

Trimethylantimony was detected by gas chromatography-mass spectrometry (GC-MS) in the headspace of a soil enrichment culture designed to promote growth of clostridia. Clostridial isolates from the soil enrichment culture were shown to biomethylate inorganic antimony in monseptic culture, using hydride generation-gas chromatographyatomic absorption spectrometry (HG-GC-AAS). GC-MS profiles of headspace gases from soil enrichment cultures shown to generate trimethylantimony, were used to select characterised Clostridium spp for assessment of antimony biomethylation capability. Involatile methylantimony species (up to 21 microg Sb dm(-3)) were detected by HG-GC-AAS in the medium of monoseptic cultures of C. acetobutylicum, C. butyricum and C. cochlearium. The relative quantities of involatile mono-, di- and trimethylantimony species produced over the course of a 28-day cultivation period is consistent with trimethylantimony oxide being a final product of antimony biomethylation by these bacteria, with mono- and dimethylantimony species appearing transiently in the cultures as intermediates of an antimony biomethylation pathway. Clostridia may be the principal agents of antimony biomethylation in methanogenic environments and could give rise to methylated forms of antimony in both the aqueous and gaseous phases.

Evaluation of cot mattress inner foam as a potential site for microbial generation of toxic gases

Recent reports of biovolatilisation of phosphorus and antimony by anaerobic bacteria and of leaching of phosphorus and antimony fire-retardant additives from PVC cot mattress covers, indicate that the polyurethane inner-foam of cot mattresses could be a site for generation of toxic gases of group 15 elements. A toxic gas hypothesis for sudden infant death syndrome (SIDS) involving polyurethane foam of cot mattresses was proposed and tested experimentally. Levels of antimony, phosphorus, arsenic and bismuth were determined at four sites for 44 SIDS and 50 control (no death) cot mattress foams. There was no evidence to suggest that the levels of these elements in cot mattress foam have a causal relation to SIDS. Leaching of antimony trioxide from PVC mattress covers could account for detectable levels of this element in 52% of the cot mattress samples analysed. Volatile forms of antimony, phosphorus, arsenic and bismuth was not detected in the headspace of mixed or monoseptic cultures of anaerobic bacteria containing polyurethane foam. Past microbial activity had given rise to involatile methylated species of antimony in some of the cot mattress foams tested (61%, n = 24). Abiotic oxidation of biogenic trimethylantimony together with physical adsorption of methylantimony forms to the polyurethane foam matrix could account for the apparent absence of "escaped" volatile antimony species in culture headspaces of incubation vial. There was no evidence to suggest that levels of trimethylantimony or total methylantimony forms in cot mattress foams have a causal relation to SIDS.

Dendro-somatic distribution of calcium-mediated electrogenesis in purkinje cells from rat cerebellar slice cultures

The role of Ca2+ entry in determining the electrical properties of cerebellar Purkinje cell (PC) dendrites and somata was investigated in cerebellar slice cultures. Immunohistofluorescence demonstrated the presence of at least three distinct types of Ca2+ channel proteins in PCs: the alpha1A subunit (P/Q type Ca2+ channel), the alpha1G subunit (T type) and the alpha1E subunit (R type). In PC dendrites, the response started in 66 % of cases with a slow depolarization (50 +/- 15 ms) triggering one or two fast (approximately 1 ms) action potentials (APs). The slow depolarization was identified as a low-threshold non-P/Q Ca2+ AP initiated, most probably, in the dendrites. In 16 % of cases, this response propagated to the soma to elicit an initial burst of fast APs. Somatic recordings revealed three modes of discharge. In mode 1, PCs display a single or a short burst of fast APs. In contrast, PCs fire repetitively in mode 2 and 3, with a sustained discharge of APs in mode 2, and bursts of APs in mode 3. Removal of external Ca2+ or bath applications of a membrane-permeable Ca2+ chelator abolished repetitive firing. Tetraethylammonium (TEA) prolonged dendritic and somatic fast APs by a depolarizing plateau sensitive to Cd2+ and to omega-conotoxin MVII C or omega-agatoxin TK. Therefore, the role of Ca2+ channels in determining somatic PC firing has been investigated. Cd2+ or P/Q type Ca2+ channel-specific toxins reduced the duration of the discharge and occasionallyinduced the appearance of oscillations in the membrane potential associated with bursts of APs. In summary, we demonstrate that Ca2+ entry through low-voltage gated Ca2+ channels, not yet identified, underlies a dendritic AP rarelyeliciting a somatic burst of APs whereas Ca2+ entry through P/Q type Ca2+ channels allowed a repetitive firing mainly by inducing a Ca2+-dependent hyperpolarization.

Phosphine generation by mixed- and monoseptic-cultures of anaerobic bacteria

A microbial basis for bioreductive generation of phosphine is proposed, which could account at least in part for the presence of this toxic gas in natural anaerobic environments and in sewage and landfill gases. Phosphine generation under anaerobic growth conditions was dependent upon both the culture inoculum source (animal faeces) and enrichment culture conditions. Phosphine was detected in headspace gases from mixed cultures under conditions promoting fermentative growth of mixed acid and butyric acid bacteria, either in the presence or absence of methane generation. Monoseptic cultures of certain mixed acid fermentors (Escherichia coli, Salmonella gallinarum, and Salmonella arizonae) and solvent fermentors (Clostridium sporogenes, Clostridium acetobutyricum and Clostridium cochliarium) also generated phosphine. Such fermentative bacteria participate in the multi-stage process of methanogenesis in nature. Generation of phosphine by these bacteria, rather than by methanoarchaea themselves, could explain the apparent correlation between methanogenesis and the formation of phosphine in nature.

Distribution of the voltage-dependent calcium channel alpha1G subunit mRNA and protein throughout the mature rat brain

The molecular identity of a gene which encodes the pore-forming subunit (alpha1G) of a member of the family of low-voltage-activated, T-type, voltage-dependent calcium channels has been described recently. Although northern mRNA analyses have shown alpha1G to be expressed predominantly in the brain, the detailed cellular distribution of this protein in the central nervous system (CNS) has not yet been reported. The current study describes the preparation of a subunit specific alpha1G riboprobe and antiserum which have been used in parallel in situ mRNA hybridization and immunohistochemical studies to localize alpha1G in the mature rat brain. Both alpha1G mRNA and protein were widely distributed throughout the brain, but variations were observed in the relative level of expression in discrete nuclei. Immunoreactivity for alpha1G was typically localized in both the soma and dendrites of many neurons. Whilst alpha1G protein and mRNA expression were often observed in cells known to exhibit T-type current activity, some was also noted in regions, e.g. cerebellar granule cells, in which T-type activity has not been described. These observations may reflect differences between the subcellular distribution of channels that can be identified by immunohistochemical methods compared with electrophysiological techniques.

The expression of voltage-dependent calcium channel beta subunits in human hippocampus

The beta subunits of voltage-dependent calcium channels (VDCC) modulate the electrophysiology and cell surface expression of pore-forming alpha1 subunits. In the present study we have investigated the distribution of beta1,beta2,beta3 and beta4 in the human hippocampus using in situ hybridization (ISH) and immunohistochemistry. ISH studies showed a similar distribution of expression of beta1,beta2 and beta3 subunit mRNAs, including labelling of the dentate granule cell layer, all CA pyramidal regions, and the subiculum. Relatively low levels of expression of beta1 and beta2 subunit mRNAs correlated with low protein expression in the immunocytochemical (ICC) studies. There was a relative lack of beta4 expression by both ISH and ICC in the CA1 region, compared with high levels of expression in the subiculum. Immunostaining for beta1 and beta2 subunits was weak and relatively homogeneous throughout the hippocampus. The beta3 and beta4 subunits appeared to be more discretely localized. In general, beta3-immunoreactivity was moderate both in cell bodies, and as diffuse staining in the surrounding neuropil. Strongest staining was observed in mossy fibres and their terminal region in the CA3 stratum lucidum. In contrast, beta4-immunoreactivity in the neuropil showed intense dendritic localisation. Unlike the other subunits, beta4-immunoreactivity was absent from CA1 pyramidal neurones but was present in a small population of interneurone-like cells. The localisation of beta3 and beta4 may represent presynaptic and postsynaptic compartments in some populations of hippocampal neurones. Comparison of beta subunit distribution with previously published data on alpha1 subunits indicates certain neuronal groups and subcellular compartments in which the subunit composition of native pre- and postsynaptic VDCC can be predicted.

Distribution of the voltage-dependent calcium channel alpha(1A) subunit throughout the mature rat brain and its relationship to neurotransmitter pathways

The alpha(1) subunit provides both the voltage-sensing mechanism and the ion pore of voltage-dependent calcium channels. Of the six classes of alpha(1) subunit cloned to date, alpha)1A) is the subject of debate in terms of its functional correlate, although it is generally thought to encode voltage-dependent calcium channels of the omega-agatoxin IVA-sensitive, P/Q type. In the present study, an alpha(1A)-specific riboprobe and antibody were used with in situ hybridisation and immunohistochemical techniques to localise alpha(1A) messenger ribonucleic acid transcripts and subunit protein throughout the mature rat brain. Dual localisation of alpha(1A) protein and markers for acetylcholine, catecholamines, and 5-hydroxytryptamine have also been performed in a number of discrete areas. Abundant and widespread distribution of alpha(1A) protein was found, with immunoreactivity occurring both in cell bodies and as punctate staining in areas of neuronal processes. Several associations were noted across alpha(1A) localisation, defined neuroanatomical regions, and neurotransmitter systems. However, alpha(1A) expression was not confined to loci corresponding to any one neurotransmitter type, although a high level of expression was observed in cholinergic neurones. The distribution of the alpha(1A) subunit in the rat corresponded well with the limited human mapping data that are available.

Biovolatilization of antimony and sudden infant death syndrome (SIDS)

1. The aerobic filamentous fungus S. brevicaulis IMI 17297 methylated antimony from Sb2O3 substrate, with the formation of gaseous trimethylantimony (TMA). No evidence was found for the generation of other gaseous antimony compounds by this organism. 2. Biovolatilization of inorganic antimony was greatest during cultivation of the fungus on solid media at 25 degrees C, and occurred more readily from antimony (III) substrates than from antimony (V) substrates. 3. Under simulated cot environment conditions (CO2 enriched atmosphere, 33 degrees C) the fungus exhibited an altered morphology and a reduced capability to volatilize inorganic antimony from the pure compound. 4. No evidence of antimony biovolatilization from cot mattress PVC was found, unless antimony was released from PVC by heat treatment (at 80 or 100 degrees C). 5. These data suggest that normal cot environment conditions are non-optimal for volatilization of antimony by S. brevicaulis, and that Sb2O3 in cot mattress PVC is not bioavailable. 6. Cot mattress isolates of S. brevicaulis also volatilized antimony (not encapsulated by PVC), whereas those of other filamentous fungi (Penicillium spp., Aspergillus niger, Aspergillus fumigatus, Alternaria sp.) and of bacteria (Bacillus spp.) did not. 7. The oxidation products of TMA may be the true determinants of toxicity for biogenic antimony gases produced in an aerobic environment.

Antimony leaching from cot mattresses and sudden infant death syndrome (SIDS)

1. Polyvinyl chloride (PVC) cot mattress covers from SIDS cases were investigated as potential sources of soluble (potentially ingestable) antimony in the cot environment. 2. Body fluids (urine, saliva) and proprietary domestic detergents/sterilizing fluids markedly enhanced leaching of antimony from PVC. Release of antimony was also enhanced at both low and high pH and by elevated temperature. The extent of antimony leaching did not correlate well with PVC content of this element. 3. These data do not support the assumption that postmortem analysis of antimony content proves exposure to gaseous antimony trihydride from mattress PVC. 4. Ingestion of antimony released from PVC could account for the high variability associated with reported detectable levels of antimony in liver from both SIDS and other infants. It could also explain suspected additional postnatal exposure to this element, which gives rise to elevated levels of Sb in the hair of some healthy infants.

The expression of voltage-dependent calcium channel beta subunits in human cerebellum

The beta subunits of voltage-dependent calcium channels, exert marked regulatory effects on the biophysical and pharmacological properties of this diverse group of ion channels. However, little is known about the comparative neuronal expression of the four classes of beta genes in the CNS. In the current investigation we have closely mapped the distribution of beta1, beta2, beta3 and beta4 subunits in the human cerebellum by both in situ messenger RNA hybridization and protein immunohistochemistry. To our knowledge, these studies represent the first experiments in any species in which the detailed localization of each beta protein has been comparatively mapped in a neuroanatomically-based investigation. The data indicate that all four classes of beta subunits are found in the cerebellum and suggest that in certain neuronal populations they may each be expressed within the same cell. Novel immunohistochemical results further exemplify that the beta voltage-dependent calcium channel subunits are regionally distributed in a highly specific manner and studies of Purkinje cells indicate that this may occur at the subcellular level. Preliminary indication of the subunit composition of certain native voltage-dependent calcium channels is suggested by the observation that the distribution of the beta3 subunit in the cerebellar cortex is identical to that of alpha(1E). Our cumulative data are consistent with the emerging view that different native alpha1/beta subunit associations occur in the CNS.

Immunohistochemical and in situ mRNA hybridisation techniques to determine the distribution of ion channels in human brain: a study of neuronal voltage-dependent calcium channels

The molecular, structural and functional characterisation of ion channels in the CNS forms an area of intense investigation in current brain research. For strategic and logistical reasons, rodents have historically been the species of choice for these studies. The examination of human CNS tissues generally presents the investigator with specific challenges that are often less problematic in animal studies, e.g. post-mortem delay/agonal status, and thus both the experimental design and techniques must be manipulated accordingly. Since much pharmaceutical interest is currently focused on neuronal ion channels, the examination of their expression in human brain material is of particular importance. We describe here the details of methods that we have developed and used successfully in the study of the expression of voltage-dependent calcium channels (VDCCs) in human CNS tissues. Presynaptic neuronal VDCCs control neurotransmitter release and are important new drug targets. They are composed of three subunits, alpha 1, beta and alpha 2/delta and multiple gene classes of each protein have been identified. Little is known, however, about the distribution of neuronal VDCCs in the human central nervous system, although initial studies have been performed in rat and rabbit.

Distribution of alpha 1A, alpha 1B and alpha 1E voltage-dependent calcium channel subunits in the human hippocampus and parahippocampal gyrus

The distribution of voltage-dependent calcium channel subunits in the central nervous system may provide information about the function of these channels. The present study examined the distribution of three alpha-1 subunits, alpha 1A, alpha 1B and alpha 1E, in the normal human hippocampal formation and parahippocampal gyrus using the techniques of in situ hybridization and immunocytochemistry. All three subunit mRNAs appeared to be similarly localized, with high levels of expression in the dentate granule and CA pyramidal layer. At the protein level, alpha 1A, alpha 1B and alpha 1E subunits were differentially localized. In general, alpha 1A-immunoreactivity was most intense in cell bodies and dendritic processes, including dentate granule cells, CA3 pyramidal cells and entorhinal cortex pre-alpha and pri-alpha cells. The alpha 1B antibody exhibited relatively weak staining of cell bodies but stronger staining of neuropil, especially in certain regions of high synaptic density such as the polymorphic layer of the dentate gyrus and the stratum lucidum and radiatum of the CA regions. The alpha 1E staining pattern shared features in common with both alpha 1A and alpha 1B, with strong immunoreactivity in dentate granule, CA3 pyramidal and entorhinal cortex pri-alpha cells, as well as staining of the CA3 stratum lucidum. These findings suggest regions in which particular subunits may be involved in synaptic communication. For example, comparison of alpha 1B and alpha 1E staining in the CA3 stratum lucidum with calbindin-immuno-reactivity suggested that these two calcium channels subunits may be localized presynaptically in mossy fibre terminals and therefore may be involved in neurotransmitter release from these terminals.

The expression of neuronal voltage-dependent calcium channels in human cerebellum

Little is known about the comparative distribution of voltage-dependent calcium channel subtypes in normal human brain. Previous studies in experimental animals have predominantly focused on the regional expression of single alpha 1 genes. We describe the preparation of riboprobes and antisera specific for human alpha 1A, alpha 1B and alpha 1E subunits and their application in comprehensive mapping studies of the human cerebellum. Within the cerebellar cortex, these pore forming proteins were found to have differential localisations when examined in adjacent sections. The alpha 1A and alpha 1B subunits broadly colocalised and were both present, though at apparently different levels, in the molecular, Purkinje and granule cell layers whilst alpha 1E was predominantly expressed in Purkinje cells. In the dentate nucleus, an area which has received little attention in previous studies, alpha 1A was highly expressed in regions in which Purkinje cell nerve terminals form synapses with deep cerebellar neurones.

Cell migration studies in the adoptive transfer of adjuvant arthritis in the Lewis rat

Adjuvant arthritis (AA) can be induced in Lewis rats by a single injection of either heat-killed Mycobacterium tuberculosis or the lipoidal amine CP20961. Concanavalin A (Con A)-stimulated T cells isolated from AA rats are able to adoptively transfer the disease to naive syngeneic recipients. It is unclear, however, whether these transferred cells traffic directly to the joint and initiate arthritis, or whether secondary host cells are responsible for activation of the disease. In the current investigation, T cells labelled with the vital fluorescent dyes Hoechst H33342 and Zynaxis PKH26-G were used to adoptively transfer adjuvant disease to naive recipients. At various stages of disease development sections of ankle joints, together with a range of soft tissues, were examined by fluorescence microscopy to determine the distribution of labelled donor cells in the recipients. Intensely fluorescent lymphocytes were observed in the liver, spleen and lymph nodes within 24 hr of adoptive transfer. Foci of such cells were clearly visible in the primary lymphoid tissues as late as 14 days after transfer. However, close examination of both ankle joint sections and patellar fat pad cells throughout the time-course of the study failed to detect any labelled cells at the lesion site. To develop these observations further, we performed adoptive transfers to nude Lewis rats (rnu/rnu) and found that they were only moderately sensitive and developed, at best, a transient arthritis. This observed difference could not be explained by a generalized lack of an inflammatory response, since we were able to elicit a zymosan peritonitis in the nude rats. However, in nude Lewis rats a striking increase in adoptively transferred AA was obtained after reconstitution with 4 x 10(8) naive syngeneic spleen cells. These combined observations suggest that a host-derived immune cell population is crucial for arthritis induction in the adoptive transfer system.