Hyperostosis associated with orbital vascular malformation

A previously healthy adult male presented with a slowly enlarging orbital mass associated with 5 mm of non-pulsatile proptosis. On imaging, a soft tissue lesion with avid contrast enhancement and associated bony hyperostosis was noted. The lesion and hyperostotic bone were surgically debulked, and significant arterial bleeding was noted intraoperatively consistent with an arteriovenous malformation. Histopathologic analysis revealed a vascular malformation with enhanced microvasculature infiltrating the periosteum. While vascular lesions elsewhere in the body can be associated with skeletal changes, bony hyperostosis is a rare feature of orbital vascular malformations.

Transorbital Endoscopic Approach to the Pterygopalatine Fossa: A Less Invasive Alternative to Traditional Access

PURPOSE

The purpose of this article and accompanying video is to demonstrate a transorbital endoscopic approach for accessing the pterygopalatine fossa (PPF). This technique does not require a skin incision, avoids dissection of critical neurovascular structures, and utilizes a comparatively small osteotomy. The 2 cases presented in this article highlight the utility of a transorbital endoscopic approach for accessing an anatomic region that has traditionally required more invasive techniques to reach.

METHODS

Description of surgical technique with 2 illustrative clinical cases and accompanying surgical video.

RESULTS

Surgical technique: A trans-conjunctival approach is taken to the inferior orbital rim, and a subperiosteal dissection is propagated posteriorly. The bone of the posterior orbital floor is then deroofed, and the superior portion of the posterior wall of the maxillary sinus is removed, allowing access to the PPF for an incisional biopsy.

CASE

A 76-year-old male with a history of left cheek squamous cell carcinoma presented with progressive V2 paresthesia and an abnormally enhancing lesion in the left PPF on MRI.

CASE

A 58-year-old male with no significant medical history presented with left facial numbness (V1-V3), ptosis, an abduction deficit, and decreased hearing. Contrast-enhanced MRI demonstrated an abnormally enhanced lesion in the left PPF extending to Meckel's cave.The transorbital approach described was used to successfully obtain a diagnostic biopsy in both cases.

CONCLUSIONS

These cases highlight the utility of a transorbital endoscopic approach to the PPF as a less morbid alternative to traditional access. Patient selection is key to identifying appropriate cases.

Randomized noninferiority study evaluating the efficacy of a postmilking teat disinfectant for the prevention of naturally occurring intramammary infections

The objective of this study was to complete a positive-control, natural exposure, noninferiority design field study to test the efficacy of a novel glycolic acid-based postmilking teat disinfectant as compared with a previously proven iodine-based postmilking teat disinfectant (positive control). The primary outcome of interest was the effect of treatment on incidence of new intramammary infections. Secondary outcomes included the effect of treatment on prevalence of infection, somatic cell count, and teat condition. After blocking by parity, approximately 300 early- to mid-lactation cows on a large Wisconsin dairy farm were randomly assigned to 1 of 2 groups. For a 12-wk period between May and August 2014, the 2 groups were dipped after each milking with either the experimental (EX) or positive control (PC) product. Individual quarters were sampled to establish bacteriological infection status at the beginning of the study, and every 2 wk thereafter, by use of a 2-stage process evaluating somatic cell count (SCC), and then culturing milk samples only when SCC exceeded a parity-specific threshold. Teat condition scoring was completed at the beginning of the study and on wk 4, 8, and 12. Mixed logistic regression was used to evaluate the effect of treatment on dichotomous outcome measures including the odds of acquiring a new infection during a given 2-wk sampling interval (incidence), the odds for presence of infection at sampling (prevalence), and odds for a normal teat skin condition score. Mixed linear regression was used to evaluate the effect of treatment on somatic cell count. For the noninferiority analysis, the upper bound of the 95% confidence interval for the difference in new infection rate between the 2 treatments (EX - PC), had to be to the left of the critical value d (0.035) to conclude that EX was noninferior relative to PC with respect to risk for new infections. Results showed that the incidence of new infections was not different for quarters dipped with EX (3.2%) as compared with PC (4.2%). Similarly, the prevalence of infection tended to be lower for quarters dipped with EX (3.92%) as compared with PC (5.03%). No overall difference was found between treatments when evaluating somatic cell count measures and teat condition scores. Because the upper bound of the 95% confidence interval of the new IMI rate difference was smaller than the predefined noninferiority limit, it was concluded that the experimental product was not inferior compared with the positive control. As such, the glycolic acid-based teat disinfectant evaluated in this study can be considered an effective postmilking teat disinfectant, as well as safe, in so far as the product was not irritating to teat skin and did not negatively affect skin condition measures, as compared with the positive control group.

Short communication: Efficacy of glycolic acid-based and iodine-based postmilking barrier teat disinfectants for prevention of new intramammary infections in dairy cattle

A positive-control, natural exposure noninferiority field study was conducted to test the efficacy of a novel glycolic acid-based postmilking barrier teat disinfectant compared with a commercial iodine-based postmilking barrier teat disinfectant (positive control). Cows from 2 pens from a California Central Valley dairy farm were dipped after milking either with the positive-control product (PC) or the experimental product (EX) over 12 wk. New intramammary infections (NIMI) were determined by biweekly sampling of all quarters of study cows and classified as a NIMI based on somatic cell count and milk bacteriological culture results. The mean quarter-level incidence risks during a 2 wk study period were 3.50% (EX) and 4.28% (PC). The majority of NIMI were caused by coagulase-negative staphylococci, followed by non-agalactiae streptococci. The study results indicated that EX was noninferior to PC, with a 17% relative efficacy (improvement) in reducing NIMI compared with the PC group. Also, quarter somatic cell count was not affected by the postmilking teat disinfectant used. Finally, the EX product was safe in terms of teat conditioning: teat condition scores were not different between study groups. The study concluded that the glycolic acid-based experimental post-dip barrier was noninferior to the control, and could be considered a safe and effective postmilking teat disinfectant.

Prenatal fat-rich diet exposure alters responses of embryonic neurons to the chemokine, CCL2, in the hypothalamus

Maternal consumption of a high-fat diet (HFD) during pregnancy is found to stimulate the genesis of hypothalamic orexigenic peptide neurons in the offspring, while HFD intake in adult animals produces a systemic low-grade inflammation which increases neuroimmune factors that may affect neurogenesis and neuronal migration. Building on this evidence and our recent study showing that the inflammatory chemokine, CCL2, stimulates the migration of hypothalamic neurons and expression of orexigenic neuropeptides, we tested here the possibility that prenatal exposure to a HFD in rats affects this chemokine system, both CCL2 and its receptors, CCR2 and CCR4, and alters its actions on hypothalamic neurons, specifically those expressing the neuropeptides, enkephalin (ENK) and galanin (GAL). Using primary dissociated hypothalamic neurons extracted from embryos on embryonic day 19, we found that prenatal HFD exposure compared to chow control actually reduces the expression of CCL2 in these hypothalamic neurons, while increasing CCR2 and CCR4 expression, and also reduces the sensitivity of hypothalamic neurons to CCL2. The HFD abolished the dose-dependent, stimulatory effect of CCL2 on the number of migrated neurons and even shifted its normal stimulatory effect on migrational velocity and distance traveled by control neurons to an inhibition of migration. Further, it abolished the dose-dependent, stimulatory effect of CCL2 on neuronal expression of ENK and GAL. These results demonstrate that prenatal HFD exposure greatly disturbs the functioning of the CCL2 chemokine system in embryonic hypothalamic neurons, reducing its endogenous levels and ability to promote the migration of neurons and their expression of orexigenic peptides.

Appropriate response to pneumococcal vaccine in celiac sprue

Hyposplenism as a complication of celiac sprue confers an increased risk of pneumococcal sepsis, but such patients do not routinely receive pneumococcal vaccine despite reports of overwhelming pneumococcal sepsis. Because antibody response in these patients has not been previously assessed, we measured pre- and postvaccination levels in 10 patients with documented sprue. All demonstrated appropriate acute antibody responses to a polyvalent pneumococcal vaccine. Vaccination of all patients with celiac sprue seems appropriate.

Sural nerve biopsies in Guillain-Barre syndrome: axonal degeneration and macrophage-associated demyelination and absence of cytomegalovirus genome

T-cell infiltration was detected by immunohistochemistry in only 2 of 10 sural nerve biopsies from patients with Guillain-Barré syndrome (GBS). The number of endoneurial macrophages, identified by the monoclonal antibody MAC 387, was increased, compared with the number in 10 cases of axonal neuropathy. Macrophage-associated demyelination was identified in 7 and axonal degeneration in 8 cases. Cytomegalovirus (CMV) genome was not detected with the polymerase chain reaction.

The clinical spectrum of peripheral neuropathies associated with benign monoclonal IgM, IgG and IgA paraproteinaemia. Comparative clinical, immunological and nerve biopsy findings

Observations have been made on a consecutive series of 62 patients with peripheral neuropathy associated with benign monoclonal paraproteinaemia. The paraprotein class was IgM in 46 cases, IgG in 11 and IgA in 5. Although showing variations between patients, the clinical picture was similar for those with either IgM or IgG paraproteins, usually consisting of a late-onset, slowly progressive, distal sensorimotor demyelinating polyneuropathy, often with tremor and ataxia as prominent features. Tremor was slightly more common in patients with IgM paraproteins, in whom there was a male preponderance. The patients with both paraprotein classes were indistinguishable clinically and electrophysiologically from chronic idiopathic demyelinating polyneuropathy. In the 5 patients with an IgA paraprotein, there was a distal sensorimotor neuropathy in 4 which was demyelinating in 1. In 1 there was proximal demyelinating motor neuropathy. Immunoglobulin deposition on myelin was observed only in the patients with IgM paraproteinaemia, more commonly with a kappa light chain. No deposition of immunoglobulin in the endoneurium was seen. IgM deposits on the perineurium are a feature of normal nerve and were present in all cases. Widely spaced myelin was confined to cases with IgM paraproteins in which immunoglobulin deposition was detected on myelin. The response to treatment could not be assessed systematically but, in general, the patients with IgG and IgA paraproteins responded more satisfactorily (to corticosteroids, cytotoxic drugs, or plasma exchange) than did those with an IgM paraprotein.

A clinicopathological study of the Guillain-Barré syndrome. Nine cases and literature review

The postmortem findings are reported from 9 cases of the Guillain-Barré syndrome with survival between 10 days and 1 yr. In 8 cases there was multifocal loss of myelin throughout the peripheral nervous system with relative preservation of axons. In 1 case there was predominant loss of axons. Inflammatory mononuclear cell infiltration was present in the peripheral nervous system of all cases except 1 case surviving a year. The extent and severity of cell infiltration was variable, usually being less prominent than in previous reports, and sometimes sparing nerves in which myelin destruction was severe. Vesicular dissolution of myelin noted by electron microscopy was considered to be a postmortem artefact. In cases examined within 30 days after the onset, immunohistochemical studies with monoclonal antibodies identified more leucocytes (PD7/2B11+) and T cells (UCHL1+) in the endoneurium than in cases examined later or control cases. These findings and recent single case reports indicate that the pathology of the Guillian-Barré syndrome is variable. This variability may reflect differences in pathogenesis, with greater cell-mediated immunity in some cases and greater antibody targeted macrophage-mediated demyelination in others.

Sarcoid neuropathy

In a case of subacute sensory and motor polyneuropathy associated with sarcoidosis, multiple epineurial and endoneurial granulomas were demonstrated in a sural nerve. Neighbouring nerve fibres were displaced by the granulomas and some were undergoing axonal degeneration. Ultrastructural and teased fibre studies showed axonal atrophy and degeneration with secondary demyelination. Histochemical studies indicated the presence of HLA-DR antigen on epithelioid cells in the granulomas. A non-specific inflammatory process in the nerve does not cause significant primary demyelination.

Creating a smoke-free environment in a medical center: an overview

Beth Israel Medical Center committed itself to a smoke-free environment on May 7, 1987 after seven months of careful study by a policy determination committee and, thereafter, seven months of meticulous planning for its announcement and implementation. The policy rests on two premises: passive smoking is harmful to nonsmokers; a medical center "employer," above all others, has a special, impelling obligation to shield persons in its environs from such exposure. The impetus came from the medical staff. The policy acceptance and commitment had the combined approval of the medical staff, administration, and trustees. The ban applies to all who serve, are served in, or otherwise visit the Center. Care was taken to prepare all staff and patients for the stringent policy effective May 7, 1987. Its medical basis was made clear. Support was arranged for smokers who were interested. Response in the first year and a half has been increasing acceptance, which reflects careful preparation as well as in depth support from the medical staff. Problems are met with discussion and reasoning, not punitively.

Perls' ferrocyanide test for iron in the diagnosis of vasculitic neuropathy

Preliminary observations suggested that arterial and arteriolar necrosis in vasculitis of the peripheral nerve leads to local haemorrhage and subsequent deposition of haemosiderin. This pigment is more readily recognized in the nerve by the sensitive Perls' test for iron than by relying on recognizing its yellow colour. To support the use of iron staining as an index of vasculitis, in addition to necrosis and fibrin deposition, we obtained the following results from nerve biopsy and autopsy nerve specimens: vasculitis confined to PNS = 5/6 iron positive; polyarteritis nodosa and Wegener's granulomatosis = 4/5 iron positive; systemic lupus erythematosus 2/3 iron positive; rheumatoid disease 1/1 iron positive; acute Guillain-Barré syndrome and subacute or chronic demyelinating polyradiculoneuropathy = 12/12 iron negative; and other perivascular inflammation in the PNS (without evidence of vasculitis) = 2/2 iron negative. One case of Churg-Strauss syndrome showed no changes on nerve biopsy. Iron staining was also demonstrated in the kidneys of five or six patients with polyarteritis nodosa.

Peripheral neuropathy associated with Castleman's disease

Four patients with polyneuropathy complicating the plasma cell variant of Castleman's disease (angiofollicular lymph node hyperplasia) are described. The neuropathy was predominantly motor and severely disabling. Vasculopathy, papilloedema, organomegaly, endocrinopathy, oedema and paraproteinaemia were variably present in these patients. Sural nerve biopsy showed changes of both demyelination and axonal loss. Capillary proliferation and endothelial hypertrophy in the epineurium and endoneurium, similar to that seen in affected lymph nodes, suggested that a diffuse vasculopathy may contribute to the neuropathy. Serum antibody activity against a variety of neural antigen preparations was not detected in any of the patients. Two untreated patients died. Substantial improvement in the neuropathy occurred in the two patients treated with cyclophosphamide and prednisolone.

A prospective study of acute idiopathic neuropathy. III. Immunological studies

The immune responses of 100 patients who presented with an acute idiopathic neuropathy were compared with those of age and sex matched controls. Blood lymphocytes and their subsets were counted with a fluorescent activated cell sorter. CD8+ (putative suppressor) lymphocytes were significantly reduced in the first week of the disease but total lymphocytes, total T and CD4+ (putative helper) cells were not altered. This reduction depended on the nature of the preceding infection. Serum complement C3 and C4 concentrations remained normal and immune complexes were rarely detected with a C1q binding assay. Complement-fixing antibodies to human peripheral nerve antigens were discovered in the serum of 7% of patients but only 1% of controls. Complement-fixing antibodies to galactocerebroside were not discovered in any sera. Enzyme-linked immunoassays detected increased antibody responses to galactocerebroside but none at all to human P2 myelin protein in the patient sera. Forty microliter of serum from five patients injected into the sciatic nerves of rats did not induce significantly more demyelination than the serum from control patients. It is concluded that auto-immune responses can only be detected by these techniques in a small minority of patients with acute idiopathic neuropathy.

Immune responses to myelin antigens in Guillain-Barré syndrome

Antibodies to nerve antigens were sought in the sera of 17 patients with acute Guillain-Barré syndrome (GBS), 11 with chronic relapsing demyelinating poly-radiculoneuropathy (CRP), 20 with other neuropathies (ON), 15 with other neurological diseases (OND) and 19 normal subjects. Complement-fixing antibodies to a suspension of human peripheral nerve tissue were identified in only 2 patients with GBS and 1 with chronic progressive neuropathy. Five GBS sera gave complement fixation reactions with rabbit sciatic nerve. The sera were also tested for galactocerebroside (Gal-C) binding activity using a solid phase assay. The range of values in all groups was the same, although the mean values for patients with GBS, ON and OND were higher than those of normal subjects. In a radioimmunoassay for antibodies to bovine P2 slightly more radiolabelled antigen was precipitated by the GBS group of sera than by sera from the other groups, but only one serum from the GBS and another from the CRP patients precipitated more than 10% of the label. Addition of bovine P2 to cultures of peripheral blood mononuclear cells from 11 patients with GBS did not cause significant stimulation. Immunoassay for antibody to myelin basic protein (MBP) showed an increased proportion of sera with low binding activity in the GBS and CRP groups. The results suggest that humoral immune responses to potentially neuritogenic antigens are found with marginally increased frequency in patients with GBS and CRP.

The binding of human IgM paraprotein from cases of polyneuropathy associated with benign monoclonal gammopathy to specific neurons of the rodent brain

Human sera from patients with IgM paraproteinaemia were screened for IgM binding to frozen sections of the rat cerebellum by the indirect immunoperoxidase procedure. Out of 18 patients with a benign IgM gammopathy and associated demyelinating polyneuropathy (PPN), 17 showed binding to the surface of specific neurons, i.e. those of the deep cerebellar nuclei and the intermediate cell of Lugaro. Examination of other regions of the mouse brain suggests that the reactivity is restricted to cells of certain nuclei of the sensory-motor system. The use of F(ab)2 and monoclonal anti-idiotype antibodies demonstrate that the binding involves the antigen binding sites of the paraprotein. This reactivity indicates that some neurons have on their surface an antigen having an hapten in common with human myelin-associated glycoprotein (MAG) and the pi granules of human Schwann cells and furthermore is an additional serological characteristic of this group of patients. In addition 3 sera from the PPN group stained a particulate component in the cytoplasm of all medium-sized and large neurons. A similar staining was found with 7 out of 52 other unselected IgM paraproteinaemias.

Immunological reaction of the demyelinating Semliki Forest virus with immune serum to glycolipids and its possible importance to central nervous system viral auto-immune disease

The avirulent demyelinating strain A7(74) of Semliki Forest virus after passage through mouse brain in vivo and mouse brain cell cultures has been shown to react immunologically with immune sera against galactocerebroside, glucocerebroside, total ganglioside and GT1b ganglioside but not against myelin or sulphatide . Semliki Forest virus is known to take host membrane glycolipid into its coat. The importance of the findings is discussed in relation to the production of a possible anti-brain cell auto-immune phenomenon and its implication in a disease such as multiple sclerosis.

IgM paraproteins with immunological specificity for a Schwann cell component and peripheral nerve myelin in patients with polyneuropathy

The sera of 9 patients with benign IgM paraproteinaemia and chronic sensorimotor neuropathy were tested for reactivity to human peripheral nerves by the indirect immunoperoxidase method. They reacted in very high titre (10(-3)-10(-6) with a cytoplasmic Schwann cell component, and to lesser degree, with peripheral nerve myelin (10(0)-10(-3). The Schwann cell staining was in the form of perinuclear cytoplasmic granules and was only seen with adult nerve. The distribution of the antigen was similar to that of the metachromatically staining Pi-granules of Reich, which accumulate in the peripheral nerves with age. Specific activity was present in the IgM and F(ab)2 fractions and could be absorbed out with peripheral nerve tissue, but not with liver. Reactivity is not a simple function of the IgM level, since many IgM paraproteins do not react. The antibody is species specific and binds to human, but not to any component of rabbit, rat or guinea pig sciatic nerves. Antigenicity is removed by pretreatment of the nerve with chloroform-methanol or periodate, but not protease or trypsin. Reactivity is restored, after periodate treatment, by exposure to sodium borohydride. It is suggested that some IgM paraproteins have a specificity for a myelin glycolipid or glycoprotein, which normally accumulates in the Pi-granules of the Schwann cell cytoplasm as a function of age.

The behaviour of immature and mature rats exposed prenatally to anti-ganglioside antibodies

Three behavioural experiments were carried out in rats born to mothers injected with anti-ganglioside antibodies between days 16 and 19 of their pregnancies. Immature animals were slower to habituate to an open-field arena and took longer to learn sequence maze when no cues were provided than did offspring of mothers who had received normal serum. The latter difference disappeared when the way through the maze was cued. In a third experiment mature rats, exposed prenatally to the antibody, showed superior adaptation on a visual discrimination task compared to their controls. It was concluded that antiganglioside modifies sensory rather than motor mechanisms in the rat.

Immunogenicity of human amniotic epithelial cells after transplantation into volunteers

Human amniotic epithelial cells do not express on their surfaces HLA-A, B, C, and DR antigens, or beta 2-microglobulin. In vitro these cells synthesise the enzymes lacking in patients with selected enzymatic deficiencies: the survival of a transplanted monolayer of human amniotic epithelial cells was therefore investigated in seven volunteers. None of the volunteers showed clinical signs of acute rejection, and amniotic epithelial cells were demonstrated by biopsy up to 7 weeks after implantation. HLA antibodies were not detected in samples of serum from four volunteers thoroughly investigated, and there was no in-vitro lymphocyte reaction to the amniotic cells in two of them. The results suggest that acute immune rejection does not occur after the transplantation of human amniotic epithelial cells.

Immune responses in experimental allergic neuritis

The antibody and cell mediated immune responses were investigated in inbred Lewis rats with experimental allergic neuritis (EAN) induced by either P2, a protein purified from the bovine cauda equina nerve roots, or whole bovine nerve root myelin. In the P2 immunised animals both antibodies to P2 detected by radioimmunoassay and cell-mediated immunity to P2 assayed by skin testing appeared before the onset of EAN and persisted during and after the disease. In the myelin immunised animals the antibody titres were lower and somewhat delayed and the skin tests became negative at the height of the disease. Complement-fixing antibodies to galactocerebroside, which have been implicated in the production of demyelination under some circumstances, could not be detected in the serum after immunisation with either P2 or myelin. EAN was transferred passively with lymph node cells from rats immunised with either P2 or myelin although anti-P2 antibodies could not be detected in the serum of recipients with EAN. The results favour a cell-mediated immune response to P2 as the most important pathogenetic mechanism in EAN induced wtih whole myelin in the rat.

Behavioural changes in adult rats following administration of antibodies again brain gangliosides

Mature rats, previously trained in a standard two-lever chamber, were injected with antibodies against ganglioside and the effect was evaluated in a series of different behavioural tests. Compared with the controls, the injected rats showed transient differences in their response to stimuli. The apparent counter-intuitive superiority of the treated animals over the controls is discussed with reference to other experimental studies performed in young rats, and to discrete pathological human conditions associated with the presence of brain antibodies.

EAE, EAN and galactocerebroside sera bind to oligodendrocytes and Schwann cells

Sera from rabbits with EAN induced by sensitization with galactocerebroside (GalC-EAN) bound to the surface of Schwann cells and oligodendrocytes in rat nervous system dispersion cultures. Sera from rabbits with bovine femoral nerve-induced EAN (FN-EAN) bound to Schwann cells, oligodendroglia and occasional fibroblasts. Sera from animals with bovine spinal cord-induced EAE (SC-EAE) bound to these cells and to some astrocytes as well. Absorption of the capacity to bind to oligodendroglia and Schwann cells suggests that GalC is the major, if not the only surface antigen on these two cell types to which these sera bind. The capacity of GalC-EAN, SC-EAE, and FN-EAN sera to bind to the surface of the cells responsible for myelin synthesis in both PNS and CNS correlates with the ability of these sera to cause both PNS and CNS demyelination in vitro and PNS demyelination in vivo.

Systemic lupus with nephritis: a long-term study

Seventy-one patients with systemic lupus erythematosus and clinical evidence of nephritis were seen during a 15-year period, and followed for a mean of seven years. Survival was calculated to be 76 per cent at five years and 57 per cent at ten years from onset of clinical nephritis; and 80, 65, 55 and 55 per cent five, ten, fifteen and twenty years from onset of clinical lupus. Renal biopsies showed mild or focal lesions in 30 per cent of patients, membranous lesions in 14 per cent and diffuse proliferative lesions in 55 per cent. However, there was no difference in the long-term outcome of the different histological groups. Nineteen patients (27 per cent) died during follow up, eleven from renal failure, six from sepsis and two from cerebral lupus. Death in renal failure is now usually a late event in lupus, even in patients with clinical evidence of severe nephritis. The prognosis of even severe lupus nephritis is now better than formerly reported. Reducing the dose of corticosteroid drugs, by the use of cytotoxic drugs such as azathioprine may have diminished the mortality from cardiovascular complications. Side effects of treatment, however, remain an important cause of death and morbidity.

An evaluation of the immunoperoxidase technique in renal biopsy diagnosis

An evaluation of the use of horseradish peroxidase labelled antisera against IgG, IgM, IgA and C3 compared with corresponding antisera labelled with fluorescein isothiocyanate has been carried out on renal biopsy material from 200 patients with renal disease. A disparity between the two methods was observed in 10-19% of the readings according to the antigen being demonstrated. The majority of differences recorded would not have influenced the executive diagnosis. Where the immunological results could have influenced the executive diagnosis, 5 probable false results were obtained using innumofluorescence and 4 with immunoperoxidase. Immunoperoxidase has the advantage over immunofluorescence in that it provides a permanent preparation which can be reviewed months or years later. In addition it provides more accurate localization of the immune deposits since the section can be counterstained with Mayer's hemalum and viewed by conventional light microscopy. In view of these advantages we recommend that serious consideration should be given to using immunoperoxidase in place of immunofluorescence for the examination of renal biopsy material.

Focal segmental sclerosis or scarred focal proliferative glomerulonephritis?

We have made a blind retrospective analysis of 334 renal biopsies, each containing more than 10 glomeruli, from adults and children with glomerulonephritis, in order to assess the clinicopathological significance of segmental lesions. These were defined as endocapillary proliferation and/or sclerosis involving capillary loops, and a less than half the glomerular tufts. On optical microscopy of paraffin-embedded material, 57 biopsies containing segmental lesions were independently classified by two observes as "focal proliferative glomerulonephritis" or "focal segmental glomerulosclerosis". These results were then reviewed with immunofluorescence, electron microscopic and clinical data and an "executive" diagnosis reached. Scarred focal proliferative glomerulonephritis could not be reliably distinguished from focal segmental glomerulosclerosis by optical microscopy alone. Some cases of focal proliferative glomerulonephritis are not associated with systemic disease and may have negative immunofluorescence findings, and we were unable to distinguish scarring in these patients from the lesion of focal segmental glomerulosclerosis with any of the tools at our disposal. Some patients with scarred focal proliferative glomerulonephritis showed profuse proteinuria, a nephrotic syndrome and progression to renal insufficiency. These cases cannot therefore be differentiated from focal segmental glomerulosclerosis by their clinical features. It would seem that the morphological lesion of focal segmental glomerulosclerosis should be regarded as focal segmental glomerular scarring from a variety of insults, rather than a distinct disease entity.

Absence of glomerular renal tubular epithelial antigen in membranous glomerulonephritis

Renal biopsies from 24 patients with membranous glomerulonephritis were examined by indirect immunofluorescence for the presence of autologous renal tubular epithelial antigen (RTE). Staining of the luminal layer of proximal tubular epithelium was found in all cases, as with normal human kidney, but granular staining along glomerular capillary walls was not observed. The role of RTE in the genesis of human membranous glomerulonephritis has not been confirmed.

IgA and glomerular disease

Serum IgA levels are raised in a proportion of children with Henoch-Schönlein disease (H. S. P.), patients with Berger's mesangial IgA disease, and in patients with glomerular lesions in association with hepatic cirrhosis. These conditions are all characterized by mesangial staining with anti-IgA antisera on immunofluorescence. It has been suggested that elevated serum IgA levels are of value in the diagnosis of these diseases. We have measured serum IgA levels by radial immunodiffusion in a variety of primary and secondary glomerular diseases. High serum IgA levels were confined to patients with glomerular IgA deposition, but were not restricted to H. S. P. and Berger's disease, nor to patients with deposition of IgA only in a mesangial pattern. Elevated salivary IgA levels were found in 3/4 patients with high serum IgA levels but we found no evidence for involvement of the secretory system in glomerular mesangial IgA deposition.

Role of antibodies to galactocerebroside in experimental allergic encephalomyelitis

The possible role of antibodies to galactocerebroside was investigated in AS rats with experimental allergic encephalomyelitis (EAE) induced by guinea-pig spinal cord. Passive immunization with rat or rabbit antiserum to galactocerebroside did not protect rats from EAE. Active immunization with galactocerebroside before the encephalitogenic challenge produced antibody to galactocerebroside but also failed to protect rats from EAE. These experiments did not support previous suggestions that antibodies to galactocerebroside are protective.

The effect of homologous and heterologous carriers on the immunogenicity of the galactocerebroside hapten

Glycolipid haptens are capable of eliciting an immune response when complexed with a protein carrier. These experiments demonstrate that an immunogenic (foreign) carrier is required.

Antibody to galactocerebroside can be produced in rats by injecting the hapten associated with heterologous (bovine serum albumin) but not homologous (rat serum albumin) protein. It appears after primary immunization in animals given pertussis vaccine or after repeated injections of the antigen emulsified in Freund's incomplete adjuvant. However, if Mycobacterium tuberculosis is added to the emulsion a protein carrier is unnecessary. In this case the bacilli may serve a carrier function in addition to their usual adjuvant action.

Galactocerebroside, therefore, behaves in much the same way as conventional, covalently bound, non-lipid haptens. Antibody is only produced when the hapten is bound to an immunogenic carrier or in the presence of an adjuvant, capable of providing a stimulus to replace the carrier specific `helper' function of the T cell.

Since galactocerebroside is a normal body constituent, the findings also define some of the conditions for the failure of tolerance to endogenous glycolipids in the central nervous system.

The specificity of anti-galactocerebroside antibody and its reaction with lysolecithin-solubilized myelin

Antibody to galactocerebroside can be produced in rabbits by the injection of the hapten together with a carrier protein (GC.BSA) or by immunization with the myelin fraction of brain homogenates (GC.M). The anti-galactocerebroside activity of both sera is mainly directed towards the galactose moiety of the galactolipid. In a complement fixation system they react with galactocerebroside (galactosylceramide) and monogalactosyldiglyceride, but not with glucocerebroside (glucosylceramide).

Passive cutaneous anaphylaxis can be elicited by the carrier, but not the hapten. There is no demonstrable reaction to the glycolipid itself—even when tested in association with auxiliary lipids or the carrier protein; or as a component of solubilized myelin.

The specificity of antibody to galactocerebroside appears to be unaffected by the nature of the carrier or associated proteins. This is shown by the fact that antisera to GC.BSA and GC.M react in an identical fashion with the lipid—protein complexes formed when myelin is solubilized with lysolecithin. Complement fixation is increased by solubilization, but increasing the lysolecithin/myelin ratio above the minimum necessary to render myelin completely soluble decreased the specific activity. Following isopycnic centrifugation maximum complement fixing activity was present in a fraction having a density of 1.04 at 10°, corresponding to one of three peaks of galactocerebroside concentration. However, precipitin reactions were obtained over a range of fractions of higher density.

These results suggest that galactocerebroside is present in myelin in at least two forms and provides further confirmation of the fact that this hapten is responsible for a large part of the organ-specific complement fixing and precipitating activity of anti-myelin serum.

The tuberculin reaction in the pleural cavity and its suppression by antilymphocyte serum

Tuberculin (PPD) injected into the pleural cavity of sensitized guinea-pigs results in the development of a large protein-rich effusion over a period of 24 hours. In the early stages the effusion contains large numbers of polymorphonuclear leucocytes, but later mononuclear cells (lymphocytes and monocytes) predominate. At 24 hours a small percentage of the lymphocytes have the character of lymphoid blast cells, while some of the monocytes contain phagocytosed polymorphonuclear cells or nuclear debris.

A similar phenomenon can be elicited in mice sensitized with complete Freund's adjuvant. However, in these animals the volume of the effusion is small and difficult to measure accurately.

The effusion in the guinea-pig is completely suppressed by antilymphocyte serum (ALS). This effect is relatively long lasting (compared with its transient action on a nonspecific inflammatory lesion due to turpentine) and recovery parallels the return of the tuberculin reaction in the skin—providing further confirmation that the effusion is due to delayed hypersensitivity.

The tuberculin PPD reaction in the pleural cavity provides a useful model of delayed hypersensitivity in which exudate and viable inflammatory cells can be collected for study during the development of the lesion.

Cerebral vascular permeability and cellular infiltration in experimental allergic encephalomyelitis

Cerebral vascular permeability was measured in guinea-pigs developing experimental allergic encephalomyelitis (EAE). A sensitive double radio-isotope method was used which allowed the permeability changes to be measured independently of alterations in cerebral blood volume. The onset of the disease was accompanied by a striking increase in vascular permeability, but there was no evidence that this change preceded the entry of inflammatory cells into the brain and cord. Injection of serum from rabbits with EAE into normal guinea-pigs had no measurable effect on the cerebral vessels.

These findings are consistent with the view that EAE is a cell-mediated lesion and provide no support for the suggestion that the initial damage is due to circulating antibody.

Immunological reactions with lysolecithin-solubilized myelin

Rat brain myelin purified by ultracentrifugation in a sucrose gradient was solubilized with lysolecithin. The water soluble protein—lipid complexes obtained were antigenic and encephalitogenic and in a complement fixation system reacted more efficiently with anti-myelin sera than intact myelin itself. Increasing the lysolecithin/myelin ratio above the minimum required to render myelin completely soluble reduced the amount of complement fixed. This suggests that solubilization increases the number of accessible antigenic sites, while further addition of lysolecithin to the molecular surface interferes with its antibody combining capacity. Following isopycnic centrifugation the maximum complement-fixing activity was present in a fraction having a density of 1.04 at 10°, corresponding to one of three peaks of galactocerebroside concentration.

Antibody to lysolecithinized myelin reacts with the myelin moiety of the complex and not with lysolecithin, since it can be removed by absorption with particulate myelin and it will not react with lysolecithinized red cell ghosts.

Anti-rat myelin antiserum cross-reacts with lysolecithinized myelin from other mammalian species; to a lesser degree with frog, and only minimally with dogfish myelin.

It is suggested that solubilization by lysolecithin may prove a convenient starting point for immunochemical studies on myelin by providing lipid—protein complexes which reflect the structure of the native material.

Leukemia virus activation in chronic allogeneic disease

Young adult (BALB/c x A/J)F(1) hybrid mice have no detectable leukemia viruses. When inoculated with parental BALB/c spleen lymphoid cells, also free of detectable virus, leukemia viruses rapidly become activated in the injected host. Because of similarities between such graft-induced allogeneic disease and spontaneous autoimmunity, it is proposed that autoimmune reactions may activate latent viruses.

The effect of anti-lymphocyte serum on experimental allergic encephalomyelitis in the guinea-pig

An anti-thymocyte serum completely suppressed the clinical and histological manifestations of experimental allergic encephalomyelitis (EAE) in the guinea-pig. Long-term suppression of EAE was obtained with a relatively short course of treatment (8 days) although tolerance did not develop and the disease recurred in an attenuated form. Early treatment (0–8 days) was as effective as that given later, at a time (10–18 days) when the inflammatory lesion normally develops in the brain and cord. This suggests that the major effect is immunosuppressive rather than anti-inflammatory. A definite protective effect was also demonstrated within 24 hr of giving the serum to paralysed animals, implying a `peripheral' action upon sensitized lymphocytes or some additional anti-inflammatory component. The brain lesions seen in some long term survivors showed more advanced demyelination than is commonly seen in EAE, probably due to the chronicity of the lesion.