Can We Miniaturize CT Technology for a Successful Mobile Stroke Unit Roll-Out?

Mortality from stroke remains high in Australia, especially for patients located outside the metropolitan cities. This is because they have limited access to specialized stroke facilities for optimal stroke treatment. Mobile stroke units have the capability to take CT scanners out to the patient however current CT commercial scanner designs are large and heavy. As such, this paper aims to design and develop a lightweight CT scanner for use in a mobile stroke unit (either road-based or air-based ambulance) to bring healthcare solution to patients in the rural and remote areas. We used the engineering design optimization approach to redesign and reduce the weight of the existing CT scanner with without compromised it structural performance. We managed to reduce the weight the CT scanner by three-fold while reducing design costs by allowing numerous simulations to be performed using computer software to achieve our design goals. The results are not only useful to optimize CT scanner structure to retrofit on a mobile stroke unit, but also bring the medical device solution to the market and support scalable solution to the larger community. Such an advance will allow for improved equity in healthcare whereby patients can be treated irrespective of location.

High T cell responses to the glutamic acid decarboxylase (GAD) isoform 67 reflect a hyperimmune state that precedes the onset of insulin-dependent diabetes.

Pancreatic islet beta-cell destruction leading to insulin-dependent diabetes mellitus (IDDM) is an autoimmune T cell-mediated process. Peripheral blood T cells, which proliferate to islet antigens such as glutamic acid decarboxylase (GAD), (pro)insulin or tyrosine phosphatase IA-2, can be detected in at-risk, first degree relatives of people with IDDM. However, cross-sectional studies cannot define the relationship between T cell responses and progression to IDDM. Longitudinal studies were therefore undertaken on 50 at-risk, first degree relatives tested at least yearly for up to 4 years, during which time five developed IDDM. Peripheral blood T cell responses to a GAD67(aa208-404)-glutathione-S-transferase (GST) fusion protein, GST, insulin and tetanus toxoid were measured, together with antibodies to islet cells, GAD, insulin and IA-2. High levels of antibodies to GAD or insulin were generally associated with low T cell responses to these antigens. Relatives who developed IDDM were characterized by high levels of antibodies to insulin and/or islet cells, and high T cell responses to GAD67-GST and tetanus, but not insulin, in the 24 months before clinical diagnosis. Cross-sectionally, T cell responses to GAD67(aa208-404)-GST and to full-length GAD65-GST were highly correlated (r=0.75, P<0.002). In conclusion, increased cellular immunity to the mid region of GAD67 was a marker of late pre-clinical IDDM, but appears to reflect a more general, transient state of cellular immune hyperresponsiveness.

Natural history of humoral immunity to glutamic acid decarboxylase in non-obese diabetic (NOD) mice.

Autoantibodies to glutamic acid decarboxylase (GAD) are present in humans before and after the onset of clinical insulin-dependent diabetes (IDD). The non-obese diabetic (NOD) mouse, a model of human IDD, develops mononuclear cell infiltration of the pancreatic islets ('insulitis') associated particularly in females with T cell-mediated destruction of the islet beta cells. In NOD mice of both sexes we detected serum antibodies to GAD (GAD Ab) that precipitate mouse brain GAD enzymatic activity. Antibodies in NOD sera also precipitate a M(r) 65,000 protein from Triton X-100 extracts of 35S-methionine-labelled NOD islets, identical in size to that precipitated by a monoclonal antibody to GAD. GAD Ab were not detected in other mouse strains. There were significant differences in the frequency, level and age at initial detection of GAD Ab between females of the NOD/Lt and NOD/WEHI lines, previously shown to have a higher and lower incidence of diabetes, respectively. Comparing NOD/Lt (n = 26) and NOD/WEHI (n = 20) females, in which diabetes occurred in 38% and 20% by 150 days, the frequency of elevated GAD Ab was 50 vs. 80%, the mean maximum GAD Ab level 21.1 vs. 30.6% and the mean age at which GAD Ab were first detected 94 vs. 45 days. No significant differences in these parameters were observed between male mice of either line. There was a significant negative correlation between the level of GAD Ab and the degree of insulitis in female mice from both lines. GAD Ab were not a prerequisite for the development of diabetes. In 7 of 10 female mice the onset of diabetes was preceded by a decrease of GAD Ab levels into the normal range. These findings indicate that, while GAD is a target of autoimmunity in the NOD mouse, GAD Ab do not necessarily correlate with the development of diabetes. Indeed, the difference between the two NOD lines and the inverse relationship with insulitis suggests that a strong humoral response to GAD may be associated with a less destructive pathology, as proposed in humans 'at-risk' for IDD.

Enhanced expression of Ca2+ channels by nerve growth factor and the v-src oncogene in rat phaeochromocytoma cells.

1. Rat phaeochromocytoma (PC12) cells were used to investigate the expression of Ca2+ channel types during neuronal differentiation. Neuronal differentiation was induced by treatment with nerve growth factor (NGF) or by activation of a temperature-sensitive tyrosine kinase (pp60v-src) in genetically modified PC12 (PC12/v-src) cells. PC12 cells differentiated morphologically in the presence of NGF. When grown at the permissive temperature of 37 degrees C which activates the kinase activity of pp60v-src, PC12/v-src cells differentiated morphologically with the extension of neurites. In contrast, PC12/v-src cells grown at the non-permissive temperature of 40 degrees C continued to divide and were morphologically indistinguishable from control PC12 cells. 2. Whole-cell Ca2+ currents were measured in PC12 cells using Ba2+ as the charge carrier. Ba2+ currents measured at the peak of the current-voltage curve from a holding potential of -80 mV were -0.28 +/- 0.04 nA (mean +/- S.E.M.) in control PC12 cells compared to -1.25 +/- 0.16 nA in NGF-differentiated cells. The current density increased from 9.4 +/- 0.7 pA/pF in control PC12 cells to 22.8 +/- 2.4 pA/pF in NGF-differentiated PC12 cells. Ba2+ currents were -0.24 +/- 0.04 nA in undifferentiated PC12/v-src cells grown at the non-permissive temperature of 40 degrees C compared to -0.95 +/- 0.16 nA in differentiated PC12/v-src cells grown at the permissive temperature of 37 degrees C. The current density increased from 4.5 +/- 0.5 pA/pF in PC12/v-src cells grown at the non-permissive temperature of 40 degrees C to 13.3 +/- 2.4 pA/pF in PC12/v-src cells grown at the permissive temperature of 37 degrees C. 3. The sensitivity of Ba2+ currents to omega-conotoxin GVIA (omega-CgTX) was determined for currents measured at the peak of the current-voltage curve (0 mV in 10 mM Ba2+) from a holding potential of -80 mV. In NGF-differentiated PC12 cells, 10 microM omega-CgTx inhibited 68.1 +/- 3.2% of the total Ba2+ current compared to 35.9 +/- 4.1% in control cells. The density of the omega-CgTX-sensitive current increased from 3.3 +/- 0.4 pA/pF in control cells to 15.7 +/- 2.0 pA/pF in NGF-differentiated cells. In differentiated PC12/v-src cells grown at 37 degrees C, omega-CgTX inhibited 52.2 +/- 4.2% of total Ba2+ current compared to 41.1 +/- 3.8% in PC12/v-src cells grown at 40 degrees C. The density of the omega-CgTX-sensitive current increased from 1.9 +/- 0.3 to 7.4 +/- 2.0 pA/pF with v-src-mediated differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Glutamic acid decarboxylase autoantibodies in preclinical insulin-dependent diabetes.

Insulin-dependent diabetes mellitus (IDDM) is associated with serum antibodies that precipitate a 64-kDa pancreatic islet cell protein reported to be glutamic acid decarboxylase (GAD; glutamate decarboxylase, EC 4.1.1.15). Previously, antibodies to GAD were found in the rare neurological disorder stiff man syndrome. To demonstrate directly antibodies to GAD, enzymatically active GAD was first purified from fresh human cerebellum. Brain GAD activity was precipitated by noninhibitory antibodies in the sera of 16/26 (62%) subjects defined as having preclinical IDDM (islet cell antibody-positive first-degree relatives of a person with IDDM), 3/13 (23%) with recent-onset IDDM, and 3/3 with the stiff man syndrome. In addition, sera of 5/26 (19%) preclinical and 2/13 (15%) recent-onset IDDM subjects contained antibodies that precipitated GAD but inhibited its activity. Thus, overall, 21/26 (81%) preclinical and 5/13 (38%) recent-onset IDDM subjects had antibodies that precipitated GAD activity. Antibodies to GAD were not detected in sera from subjects with other autoimmune diseases (n = 29) or healthy controls (n = 14). GAD affinity-purified to homogeneity (specific activity, 58 units/mg) was specifically immunoprecipitated as a single 60-kDa species by the IDDM sera. In an ELISA incorporating whole mouse brain GAD captured by the GAD-6 monoclonal antibody the frequencies of GAD antibodies for all subject groups were indistinguishable from those found by precipitation of human brain enzymatic activity. We conclude that (i) GAD is an (auto)antigen in a majority of subjects operationally defined as having preclinical IDDM, (ii) pancreatic islet and brain GAD are likely to be cross-reactive, and (iii) the majority of GAD antibodies are directed away from the catalytic site of the brain enzyme. The lower frequency of GAD antibodies in recent-onset IDDM subjects indicates either that immunoreactivity is lost with near-total beta-cell destruction or that GAD antibodies denote a low risk of progression to clinical disease.

Reactivity to human islets and fetal pig proislets by peripheral blood mononuclear cells from subjects with preclinical and clinical insulin-dependent diabetes.

A simple, direct assay for T-lymphocyte reactivity to islet antigen(s) in human insulin-dependent diabetes mellitus (IDDM) should facilitate preclinical diagnosis and the evaluation of intervention therapy to avert autoimmune-mediated beta-cell destruction. In subjects with preclinical or clinical IDDM, we measured the reactivity of peripheral blood mononuclear cells (PBMCs) incubated over 6 days with either adult human islets or fetal pig proislets, or other fetal pig tissues, and with human insulin. With islets, the stimulation index (SI) of [3H]thymidine uptake by PBMCs exceeded the mean + 2SD of control subjects in 6 of 6 preclinical subjects (SI 8.7 +/- 3.7), 7 of 11 clinical subjects (SI 5.2 +/- 3.4), and 1 of 12 control subjects (SI 2.7 +/- 1.7); with insulin, the responses were less in frequency and magnitude, being 4 of 6 (2.7 +/- 1.6), 3 of 11 (2.2 +/- 1.1), and 0 of 12 (1.20 +/- 0.55), respectively. The mean responses to islets of PBMCs from preclinical and clinical subjects differed significantly from control subjects (P less than 0.02 by 2-tailed Kruskal-Wallis test). Secretion of granulocyte macrophage colony-stimulating factor by PBMCs over 6 days was assayed in the preclinical group and generally paralleled the uptake of [3H]thymidine. PBMC reactivity to islets appeared to be at least as sensitive a marker of preclinical IDDM as autoantibodies to a 64,000-Mr protein, presumably the enzyme glutamic acid decarboxylase, in fetal pig proislets. In conclusion, islet-reactive T lymphocytes in subjects with preclinical and clinical IDDM can be identified in bulk culture of PBMCs.(ABSTRACT TRUNCATED AT 250 WORDS)

Alpha-bungarotoxin binds to human acetylcholine receptor alpha-subunit peptide 185-199 in solution and solid phase but not to peptides 125-147 and 389-409.

The nicotinic acetylcholine receptor (AChR) of human skeletal muscle has a reducible disulfide bond near the neurotransmitter binding site in each of its alpha-subunits. By testing a panel of overlapping synthetic peptides encompassing the alpha-subunit segment 177-208 (containing cysteines 192 and 193) we found that specific binding of 125I-labelled alpha-bungarotoxin (alpha-BTx) was maximal in the region 185-199. Binding was inhibited by unlabelled alpha-BTx greater than d-tubocurarine greater than atropine greater than carbamylcholine. Peptide 193-208 did not bind alpha-BTx, whereas 177-192 retained 40% binding activity. Peptides corresponding to regions 125-147 (containing cysteines 128 and 142) and 389-409, or peptides unrelated to sequences of the AChR failed to bind alpha-BTx. No peptide bound 125I-alpha-labelled parathyroid hormone. The apparent affinity (KD) of alpha-BTx binding to immobilized peptides 181-199 and 185-199 was approximately 25 microM and 80 microM, respectively, in comparison with alpha-BTx binding to native Torpedo ACh receptor (apparent KD approximately 0.5 nM). In solution phase, both peptides effectively competed with solubilized native human AChR for binding of alpha-BTx, and peptide 185-199 showed little evidence of dissociation after 24 h. Peptides that bound alpha-BTx did so when sulfhydryls were reduced. Cysteine modification, by N-ethylmaleimide or acetamidomethylation, abolished alpha-BTx-binding activity. The data implicate the region of cysteines 192 and 193 in the binding of neurotransmitter to the human receptor.

Antagonism of voltage-gated calcium channels in small cell carcinomas of patients with and without Lambert-Eaton myasthenic syndrome by autoantibodies omega-conotoxin and adenosine.

The Lambert-Eaton myasthenic syndrome (LES) is an autoimmune presynaptic disorder of peripheral cholinergic neurotransmission in which there is often an associated small cell lung carcinoma (SCC). SCC lines established from patients with and without LES exhibit a Ca2+ influx response to depolarization by K+ that is consistent with the presence of voltage-gated Ca2+ channels. Autoantibodies antagonistic to SCC Ca2+ channel activity were found exclusively in patients with LES, independent of cancer status. Depolarization-induced uptake of 45Ca2+ by SCC lines was reduced maximally after 3-4 days of exposure to serum immunoglobulins from 14 of 19 LES patients, while 53 control immunoglobulins (including patients with SCC, other tumors, other paraneoplastic syndromes, and other neurological and autoimmune diseases) were without effect. The snail neurotoxin omega-conotoxin of subtype GVIA, which is a specific antagonist of presynaptic Ca2+ channels, inhibited K+-stimulated Ca2+ uptake in a dose-dependent manner that was essentially irreversible. Adenosine, reported to be a specific antagonist of neuronal Ca2+ channels, also impaired voltage-stimulated Ca2+ influx in SCC. Use of LES patients' IgG and omega-conotoxin in further studies of SCC may facilitate identification and purification of the LES antigen(s) and yield a quantitative serological test for diagnosing this autoimmune paraneoplastic syndrome.

Oral vaccination. Identification of classes of proteins that provoke an immune response upon oral feeding.

Oral immunization of an animal is generally hard to achieve unless large quantities of antigen are administered. In this study a number of antigens were tested for their ability to elicit a systemic immune response upon oral administration. It was found that bacterial pili, LTB, lectins, and a viral hemagglutinin were all able to elicit significant antibody titers upon oral feeding. The immune response thus generated to LTB and K99 pili could be completely abolished by cofeeding a number of sugars that have close structural homology to the terminal sugars of the GM1 and GM2 gangliosides to which these molecules are known to bind. All of the proteins that were active in oral immunization are known to possess "lectin or lectin-like" binding activities. It is therefore proposed that these molecules are able to bind to glycolipids and glycoproteins on the intestinal mucosa and to stimulate these cells to transport the proteins into the systemic circulation, thereby eliciting a systemic immune response. Molecules that did not possess this binding activity were unable to elicit significant responses at the doses tested.

65-70 kD protein identified by immunoblotting as the presumptive gastric microsomal autoantigen in pernicious anaemia.

Sera from 20 of 24 patients with pernicious anaemia reacted by immunoblotting with a 65-70 kD protein in canine and rodent gastric mucosal cells enriched for 80-90% parietal cells, and in microsomal preparations derived from these cells. All 20 reactive sera were positive for parietal cell microsomal antibody demonstrated by immunofluorescence. Eighteen parietal cell microsomal antibody-positive sera from patients with unconfirmed pernicious anaemia also reacted with the same 65-70 kD protein. Serum reactivity with the same 65-70 kD protein was not seen with canine and rodent liver cells or with microsomal preparations derived from these cells. Sera from 10 patients with chronic active hepatitis, 10 with scleroderma and 10 with rheumatoid arthritis and 22 healthy persons did not react with the 65-70 kD protein. These results suggest that the 65-70 kD protein is probably the parietal cell microsomal autoantigen. A second antigen of 85-90 kD mol. wt. present only in canine gastric mucosal preparations also correlates with the presence of parietal cell microsomal antibody. However, the contribution of this second antigen to parietal cell microsomal antibody reactivity remains uncertain.

Autoantibody to the gastrin receptor in pernicious anemia.

We examined serum IgG fractions from 20 patients with pernicious anemia and 25 control subjects for their capacity to inhibit binding of [125I]15-leu human gastrin-17 to parietal-cell-enriched gastric mucosal cells. IgG fractions from six patients reduced gastrin binding by 45.6 +/- 12.2 per cent, as compared with a reduction of 1.8 +/- 0.7 per cent by fractions from the 25 controls. The fractions from these six patients also reduced gastrin-stimulated [14C]aminopyrine uptake by gastric cells (an index of gastric acid secretory activity in vitro) by 50.2 +/- 8.4 per cent (mean +/- S.D.), as compared with 9.2 +/- 4.1 per cent for the controls. IgG fractions from six other patients that did not reduce gastrin binding also inhibited gastrin-stimulated [14C]aminopyrine uptake, by 48.1 +/- 9.1 per cent. These reductions in gastrin binding and aminopyrine uptake were abolished by absorption of the IgG fractions with suspensions of viable gastric mucosal cells but not by absorption with liver or kidney cells. The IgG fractions did not inhibit [3H]histamine binding or histamine-stimulated [14C]aminopyrine uptake. These results suggest that serum IgG from some patients with pernicious anemia contains autoantibodies to the gastrin receptor.

Serum from patients with pernicious anaemia blocks gastrin stimulation of acid secretion by parietal cells.

We examined 51 sera from patients with pernicious anaemia for their capacity to block maximal gastrin stimulation of acid secretion by isolated rodent gastric parietal cells. 14C-aminopyrine accumulation was used as the index of acid secretion in vitro. Sera from patients with pernicious anaemia gave significantly (P less than 0.005) more block of maximal gastrin stimulation of acid secretion (61.7 +/- 37.8%) than sera from 10 patients with systemic lupus erythematosus (19.6 +/- 17.7%), 10 with scleroderma (34.2 +/- 22.3%), five with rheumatoid arthritis (22.4 +/- 15.6%) or 30 from healthy persons (27.4 +/- 12.8%). Maximal histamine stimulation of acid secretion was not inhibited. The blocking factor was present in serum IgG fractions, and serum and IgG fractions gave parallel dose-response and dilution curves. The serum block was abolished by absorption with gastric mucosal cells and correlated with the presence of parietal cell surface autoantibody. We conclude that serum immunoglobulin in pernicious anaemia can block gastrin stimulation of acid secretion and suggest that this block may be mediated by competition with gastrin for surface receptors on parietal cells.

Monoclonal antibody to myosin derived from mice immunized with gastric mucosal cells.

A monoclonal IgMk antibody secreted by a hybrid (MUI-6) of mouse plasmacytoma NS-1 with spleen cells from a mouse immunized with canine parietal cell-enriched gastric mucosal cells was tested for immunofluorescence reactivity with gastric mucosal cells, tissue sections and monolayer cultures of rat fibroblasts. The antibody did not react with the cell membrane of parietal cells but reacted with smooth muscle fibres and skeletal muscle striations. In non-muscle cells, the antibody reacted with parietal cell cytoplasm, liver in a "polygonal" pattern, renal glomeruli, brush borders and peritubular fibrils of renal tubules, thymic medulla, brush borders of small intestinal mucosal cells, and cerebellar astrocytes, synaptic endings and synaptic glomeruli. In fibroblast monolayers, the antibody stained stress fibres in an interrupted pattern and in spreading fibroblasts, the antibody stained the microfibrillar network. Stress fibre staining was disrupted by treatment of cells with cytochalasin B. Immunoblots showed that the antibody reacted with a 200 K protein in 3T3 cells and with a preparation of myosin from rat liver.

Flow microfluorometry detects IgM autoantibody to oligodendrocytes in multiple sclerosis.

Freshly isolated canine oligodendrocytes were reacted by indirect membrane immunofluorescence with 44 sera from patients with multiple sclerosis (MS). Using analysis by flow microfluorometry (FMF), we found significant IgM antibody binding to the surfaces of oligodendrocytes in the MS sera. The fluorescence intensity of cell surface reactions for MS sera (F.I. greater than 40 = 37.2 +/- 21.34%) was significantly different (P less than 0.001) to that for 53 sera from normal subjects (10.0 +/- 8.97%), 15 sera from patients with Murray Valley encephalitis (6.18 +/- 5.3%), 22 with brain tumours (6.18 +/- 5.3%), 25 with SLE (13.42 +/- 11.65%), 7 with GBS (9.77 +/- 3.9%) and 7 miscellaneous neurological disorders (6.87 +/- 3.04%). Cell surface binding was restricted to oligodendrocytes and was absorbed out by oligodendrocytes but not by liver cells or kidney cells. Oligodendrocytes were identified by conventional histology, phase-contrast optics, electron microscopy (EM) and by cell surface reactions with anti-galactocerebroside, a specific immunocytological marker for oligodendrocytes. A cell sort of the single 0 degree FMF scatter peak followed by EM examination confirmed that the reactive cells consisted exclusively of oligodendrocytes. Viability of oligodendrocytes before and after the staining reactions, was greater than 80% as assessed by trypan blue and fluorescein diacetate exclusion. The possibility that immune reactions mediated by the surface-reactive antibody with readily accessible cell surface autoantigens in vivo may contribute to the loss of oligodendrocytes and demyelination in MS is raised.

Flow microfluorimetric analysis of autoantibody reactions with parietal cell surface membranes in pernicious anaemia.

Using flow microfluorimetry (FMF), 60 sera from patients with pernicious anaemia (PA) were examined for immunoreactivity with the surface membranes of viable canine parietal cells. FMF analyses showed that the percentage of parietal cells giving a surface staining reaction with a fluorescence intensity greater than 50 arbitrary units was 44.5 +/- 17.5% for sera from 60 patients with PA compared to 13.7 +/- 2.7% for sera from 14 patients with chronic active hepatitis, 10.7 +/- 6.7% for sera from 10 patients with systemic lupus erythematosus and 16.5 +/- 4.4% for sera from 50 healthy persons. Surface staining detected by FMF was restricted to parietal cells and abolished by absorption with parietal cell enriched preparations but not by absorption with dog or rat hepatocytes, dog or rat kidney cells, human fibroblasts, human AB red blood cells or dog gastric microsomes. The intensity of the parietal cell surface staining reactions correlated with the presence of antibody reactions with parietal cell surfaces previously demonstrated by immunofluorescence microscopy but did not correlate with the presence of microsomal or intrinsic factor autoantibodies. The results provide further support for the presence of a parietal cell surface reactive autoantibody distinct from the conventional parietal cell microsomal autoantibody.

Autoantibodies cytotoxic to gastric parietal cells in serum of patients with pernicious anemia.

We measured the complement-dependent cytotoxic activity of serum in 60 patients with pernicious anemia. Canine gastric mucosal cells served as the indicator of cytotoxicity, which was expressed as a percentage of the maximal effect produced by a cytolytic agent (Triton X-100). Serum from patients with pernicious anemia showed a higher average activity (11.8 +/- 10.3 per cent, P less than 0.001) than serum from 29 patients with systemic lupus erythematosus (1.0 +/- 1.8 per cent), 10 with scleroderma (0.1 +/- 0.1 per cent), 10 with rheumatoid arthritis (0.6 +/- 0.6 per cent), 22 with multiple sclerosis (0.4 +/- 1.2 per cent), and 23 with chronic persistent hepatitis (0.03 +/- 0.1 per cent), and serum from 64 healthy persons (0.4 +/- 1.0 per cent). Serum from patients with pernicious anemia was not toxic to canine liver or kidney cells. Absorption with gastric mucosal cells and heat inactivation of complement abolished the cytotoxic reaction. The cytotoxic factor resided in the IgG fraction of immunoglobulin, and the amount of cytotoxicity was proportional to the IgG concentration. Cytotoxic activity correlated with the presence of parietal-cell-surface--reactive autoantibody demonstrated by immunofluorescence. We conclude that cytotoxic autoantibodies to parietal cells may contribute to the loss of such cells from the gastric mucosa of patients with pernicious anemia.

Parietal cell surface reactive autoantibody in pernicious anaemia demonstrated by indirect membrane immunofluorescence.

We examined, in a 'double blind' study, 60 sera from patients with pernicious anaemia for immunofluorescence reactivity with the surface membranes of viable parietal cells isolated from dog stomachs. Fifty-three sera (88%) gave an IgG autoantibody reaction with the surface membranes of parietal cells. Surface staining was also seen with parietal cells from monkey, pig, rat and mouse. The parietal cell surface reactive autoantibody was not found in any of 14 sera from patients with chronic active hepatitis, 10 from patients with systemic lupus erythematosus and 50 from healthy persons. The surface reactivity autoantibody was present in 13 of 14 sera without parietal cell microsomal antibody, 28 of 31 sera without intrinsic factor antibody and in four of four sera without microsomal and intrinsic factor antibodies. Absorption with parietal cell enriched gastric mucosal cells neutralized the activity of the surface reactive but not the microsomal antibody and cross absorption with gastric microsomes neutralized the activity of the microsomal but not the surface reactive antibody. Surface staining of parietal cells was not abolished by absorption with dog or rat hepatocytes, dog or rat kidney cells, human fibroblasts or human AB red blood cells. The results suggest that the parietal cell surface reactive antibody is probably different from the microsomal antibody. Immune reactions of the cell surface reactive antibody with parietal cell surface antigens may play a role in the pathogenesis of the gastric lesion in pernicious anaemia.

Autoantibodies to fibroblasts in scleroderma.

Sera from 33 patients with scleroderma were examined for immunofluorescent reactivity with viable or acetone-fixed fibroblasts. All 33 sera reacted with the cell surface membranes of viable fibroblasts. 23 of 33 sera (70%) also reacted with nuclei of acetone-fixed fibroblasts. The commonest nuclear staining pattern was homogeneous (46%) followed by nucleolar (36%) and speckled (23%). 70% showed more than 1 staining pattern in the same serum. Antibody titres of homogeneous and nucleolar staining patterns (1:8 to 1:1024) were generally higher than those of the speckled pattern (1:8 to 1:256). No change in pattern or titre was noted in sera from 4 patients over a 10-12 month period. Antibody in sera with homogeneous or nucleolar staining patterns belonged to one or more of the 3 major antibody classes, IgG, IgM or IgA while antibody in sera with a speckled nuclear pattern belonged to the IgM class only. No correlation was found between the pattern of anti-nuclear reactivity and visceral involvement.