Introducing a new proforma for the safe use of intraoperative tourniquets in orthopaedic surgery

INTRODUCTION

The routine use of pneumatic tourniquets in orthopaedic surgery is widely adopted in current practice; however, practice varies considerably based mainly on anecdotal and cultural traditions. This Quality Improvement Project evaluated current service as per the newly published British Orthopaedic Association Standards for Trauma & Orthopaedics guideline on 'The Safe Use of Intraoperative Tourniquets'.

METHODS

Patient records were reviewed retrospectively for all patients who underwent orthopaedic surgery in September 2021 at one NHS hospital trust. Simultaneously, a nine-question survey was distributed to the orthopaedic teams allowing assessment of non-quantifiable aspects of the guidelines. The results were delivered as a local presentation, and trust-wide dissemination of posters using the mnemonic 'PRESSURE' was used to educate staff. The quantitative audit was repeated twice, after this intervention (March 2022) and after the advent of a new electronic patient record system with an online proforma (January 2023).

RESULTS

There was significant improvement (p<0.05) in all aspects of tourniquet documentation between the audit cycles. Maximum advised tourniquet duration was exceeded in <2% of cases regardless of guideline publication. Recommended pressures were used in less than one-third of cases in all audit cycles, with no significant change throughout. More than 50% of respondents sized their tourniquet on 'whatever looked best fit'.

CONCLUSIONS

Despite tourniquet usage being part of the UK Trauma & Orthopaedic Surgery curriculum, this study is the first to highlight a lack of compliance with 'gold standard' guidelines and the need for increased training for staff to ensure patients are exposed to the safest possible environment. Although electronic proformas can aid recording of information, the limitation to change is cultural tradition and anecdotal experience.

660 Trapeziectomy Versus Joint Replacement for First Carpometacarpal (CMC-1) Joint Osteoarthritis: A Systematic Review and Meta-Analysis

Aim

The challenge of managing first carpometacarpal (CMC-1) joint osteoarthritis is the lack of guidance on which surgical intervention is superior. This systematic review and meta-analysis compares joint replacement (JR) and trapeziectomy techniques to provide an update.

Method

In August 2020, MEDLINE, Embase and Web of Science were searched for eligible studies that compared these two techniques for the treatment of CMC-1 joint osteoarthritis (PROSPERO registration ID: CRD42020189728). Primary outcomes included the Disabilities of the Arm, Shoulder and Hand (DASH), QuickDASH and pain visual analogue scale (VAS) scores. Secondary outcomes, such as total complication, dislocation, and revision surgery rates, were also measured.

Results

From 1909 studies identified, 14 studies (1005 patients) were eligible. Our meta-analysis found that post-operative QuickDASH score was lower for patients in the JR group, indicating decreased disability following this technique (5 studies, p = 0.0002). However, pain VAS scores were similar between the two groups (5 studies, p = 0.22). Interestingly, JR techniques had significantly greater odds of overall complications (12 studies; OR 2.27; 95% CI 1.17-4.40, p = 0.02) and significantly greater odds of revision surgery (9 studies; OR 5.14; 95% CI 2.06-12.81, p = 0.0004).

Conclusions

Overall, based on low to moderate quality evidence, we found that JR treatments may result in better function with less disability with comparable pain (VAS) scores; however, JR has greater odds of complications and greater odds of requiring revision surgery. More robust RCTs that compare JR and TRAP with standardised outcome measures and long-term follow-up would add to the overall quality of evidence.

Novel MT-ND Gene Variants Causing Adult-Onset Mitochondrial Disease and Isolated Complex I Deficiency

Mitochondrial complex I deficiency is associated with a diverse range of clinical phenotypes and can arise due to either mitochondrial DNA (mtDNA) or nuclear gene defects. We investigated two adult patients who exhibited non-syndromic neurological features and evidence of isolated mitochondrial complex I deficiency in skeletal muscle biopsies. The first presented with indolent myopathy, progressive since age 17, while the second developed deafness around age 20 and other relapsing-remitting neurological symptoms since. A novel, likely de novo, frameshift variant in MT-ND6 (m.14512_14513del) and a novel maternally-inherited transversion mutation in MT-ND1 were identified, respectively. Skewed tissue segregation of mutant heteroplasmy level was observed; the mutant heteroplasmy levels of both variants were greater than 70% in muscle homogenate, however, in blood the MT-ND6 variant was undetectable while the mutant heteroplasmy level of the MT-ND1 variant was low (12%). Assessment of complex I assembly by Blue-Native PAGE demonstrated a decrease in fully assembled complex I in the muscle of both cases. SDS-PAGE and immunoblotting showed decreased levels of mtDNA-encoded ND1 and several nuclear encoded complex I subunits in both cases, consistent with functional pathogenic consequences of the identified variants. Pathogenicity of the m.14512_14513del was further corroborated by single-fiber segregation studies.

HIV Replication in CD4-Negative Cell Lines: Effect of Cloning, CD4 Expression and Inhibition by Dextrin Sulphate

HIV-1 infects CD4 negative (CD4) cell lines with low efficiency. Infected CD4 cells have a low copy number of HIV proviruses per cell and require a high multiplicity of infection. Following CD4 transfection, most human cell lines permit high efficiency HIV entry and replication. We have compared entry and inhibition of HIV-1 into CD4 cells and their equivalent CD4 positive (CD4+) transfectants. Entry of HIV-1 into both CD4+ and CD4− was completely inhibited by a novel sulphated polysaccharide, dextrin sulphate (DS) at 100 μg ml−1, whereas anti-CD4 antibodies only inhibited HIV infection of CD4+ cells. One glial cell line, U251SP-CD4, expressed surface CD4, but this did not increase HIV-1 susceptibility compared to the CD4− U251SP cell line. Subclones of the CD4− cell lines TE671 and U251SP were no more permissive for infection than their corresponding parental line. HIV-1 infected CD4− cells have a significantly lower provirus copy number than CD4+ cells, confirming that the block to HIV-1 replication is predominantly at entry. The action of DS was examined in conjunction with soluble recombinant CD4 (srCD4); DS was found to potentiate the inhibiting effect of srCD4.

TREATMENT OF NEUROLOGICAL MANIFESTATIONS OF SJOGREN'S SYNDROME

Neurological manifestations of primary Sjogren's syndrome appear to be wide ranging. Treatment is recommended for those with progressive neurological impairment: usually immunosuppressive treatments including cyclophosphamide, steroids, azathioprine, and anti-TNF agents.

We present three cases that didn't respond to initial steroid treatment but subsequently improved with regular infusions of intravenous immunoglobulins. In all three cases, the initial anti–Ro test was negative, but became positive after 4–11 years, an important feature to recognise in clinical practice.

Case one presented with painful dystonic spasms of the arm and leg, hemi-facial spasm, vertigo, diplopia with skew deviation, and trigeminal neuropathy. Several years later she developed features of systemic mixed connective tissue disease. Case two presented as a facial palsy, sensory trigeminal neuropathy, and spastic quadraparesis. GAD antibody was positive but she did not clinically fit with stiff man syndrome. Case three has had relapsing inflammatory optic neuropathy since the age of 19, with no clear cause initially identified.

These cases highlight the diversity in the neurological manifestations of Sjogren's syndrome, the importance of not relying on initial antibody testing, and the potential for improvement with intravenous immunoglobulins, a treatment that has less adverse effects than potentially toxic immunosuppressants.

MITOCHONDRIAL CYTOPATHY PRESENTING WITH CEREBELLAR ATAXIA

A previously fit and well 59 year old man presented with a 3 year history of slowly progressive decline in mobility with increasing unsteadiness and falls. He also reported clumsiness of both hands and his wife noted poor memory. There was no family history of note, including deafness and diabetes. He drank alcohol occasionally. On examination he had signs consistent with a cerebellar and pyramidal syndrome with subcortical cognitive impairment.

An MRI scan of the brain and spine showed significant generalised cerebral atrophy. CSF protein was 0.80g/L, with normal cell count and no oligoclonal bands. Blood tests were normal or negative for antineuronal antibodies, vitamin E, coeliac disease, autoimmune screen. Genetic tests for spinocerebellar ataxias, Freidreich's, fragile X syndrome and DRPLA were also negative. Muscle biopsy revealed mitochondrial aggregation with COX negative fibres, in keeping with a mitochondrial disorder. Genetic testing found a novel mtDNA variant (p.GLY46Asp) at low levels within the MT-CO3 gene.

He has subsequently developed myoclonus and generalised tonic clonic seizures but there is no evidence of other system involvement.

Mitochondrial disorders should be considered in the differential diagnosis of cerebellar ataxia, even in the absence of multisystem involvement or a significant family history.

Clinical assessment of the sensory ataxias; diagnostic algorithm with illustrative cases

Ataxia is a common neurological syndrome resulting from cerebellar, vestibular or sensory disorders. The recognition and characterisation of sensory ataxia remains a challenge. Cerebellar ataxia is the more common and easier to identify; sensory ataxia is often mistaken for cerebellar ataxia, leading to diagnostic errors and delays. A coherent aetiological work-up is only possible if clinicians initially recognise sensory ataxia. We discuss ways to separate sensory from cerebellar ataxia, the causes of sensory ataxia and the clinico-neurophysiological syndromes causing the sensory ataxia syndromes. We summarise a logical tiered approach as a diagnostic algorithm.

Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis

Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.

The role of working memory and attentional disengagement on inhibitory control: effects of aging and Alzheimer's disease

Patients with Alzheimer's disease have an impairment of inhibitory control for reasons that are currently unclear. Using an eye-tracking task (the gap-overlap paradigm), we examined whether the uncorrected errors relate to the task of attentional disengagement in preparation for action. Alternatively, the difficulty in correcting for errors may be caused by the working memory representation of the task. A major aim of this study was to distinguish between the effects of healthy aging and neurodegenerative disease on the voluntary control of saccadic eye movements. Using the antisaccade task (AST) and pro-saccade task (PST) with the 'gap' and 'overlap' procedures, we obtained detailed eye-tracking measures in patients, with 18 patients with probable Alzheimer's disease, 25 patients with Parkinson's disease and 17 healthy young and 18 old participants. Uncorrected errors in the AST were selectively increased in Alzheimer's disease, but not in Parkinson's disease compared to the control groups. These uncorrected errors were strongly correlated with spatial working memory. There was an increase in the saccade reaction times to targets that were presented simultaneously with the fixation stimulus, compared to the removal of fixation. This 'gap' effect (i.e. overlap-gap) saccade reaction time was elevated in the older groups compared to young group, which yielded a strong effect of aging and no specific effect of neurodegenerative disease. Healthy aging, rather than neurodegenerative disease, accounted for the increase in the saccade reaction times to the target that are presented simultaneously with a fixation stimulus. These results suggest that the impairment of inhibitory control in the AST may provide a convenient and putative mark of working memory dysfunction in Alzheimer's disease.

Secondary aorto-enteric fistula presenting over a 2-month period with recurrent gastrointestinal bleeding

A female in her sixties presented with recurrent gastrointestinal bleeding over a two-month period requiring multiple hospital admissions. Inconclusive upper and lower gastrointestinal endoscopies in addition to an initial negative CT angiogram initially left the diagnosis uncertain. A subsequent catastrophic bleed prompted a further CT angiogram that demonstrated a fistula between the aorta and third part of the duodenum with active contrast extravasation. Emergency surgery was carried out but ultimately the patient did not survive.

Renal allograft recipients fail to increase interferon-γ during invasive fungal diseases

Invasive fungal diseases are a major cause of death in renal allograft recipients. We previously reported that adjunctive recombinant human interferon-γ therapy has clinical utility for invasive fungal diseases after renal transplantation. We have now developed a rapid peripheral blood-based quantitative real-time PCR assay that enables accurate profiling of cytokine imbalances. Our preliminary studies in renal transplant patients with invasive fungal diseases suggest that they fail to mount an adequate interferon-γ response to the fungal infection. In addition, they have reduced IL-10 and increased TNF-α when compared to stable renal transplant patients. These preliminary cytokine profiling-based observations provide a possible explanation for the therapeutic benefit of adjunctive human interferon-γ therapy in renal allograft recipients with invasive fungal diseases.

Exogenous interferon-gamma immunotherapy for invasive fungal infections in kidney transplant patients

The incidence of invasive fungal infections (IFIs) in nonneutropenic solid organ transplant patients is increasing. We report our clinical experience with the use of interferon-gamma (IFN-gamma) immunotherapy in seven renal transplant patients who developed life threatening, disseminated IFIs refractory to conventional antifungal drug therapy. The infections were all microbiologically and histologically proven. The rapid cure of these disseminated infections with exogenous IFN-gamma injections was not associated with impaired kidney allograft function despite the use of liposomal amphotericin B in all cases. No clinical toxicity from the IFN-gamma immunotherapy was seen and no IFI relapsed during long-term follow-up. Our experience is both uncontrolled and in patients with unpredictable fungal infection-related outcomes. However, compared to standard approaches, the accelerated cure of life threatening, disseminated IFIs with 6 weeks of combination antifungal drug therapy and IFN-gamma immunotherapy saved lives, retained allograft function and led to substantial cost savings in this small patient group.

Treatment of refractory neurosarcoidosis with Infliximab

BACKGROUND

Neurological involvement in sarcoidosis is serious and often aggressive. Many patients respond to steroids but some show a progressive course despite treatment with steroids and even more potent immunosuppressive drugs.

OBJECTIVE

The aim of this study was to describe our experience in the treatment of refractory neurosarcoidosis with Infliximab--its effect on the course of the disease and side effects.

METHODS

A series of four patients are reported with neurosarcoidosis refractory to treatment with steroids combined with various immunosuppressive drugs in whom Infliximab was used.

RESULTS

A good response, with improvement or stabilisation of the neurological condition, was seen in all cases, without significant side effects. Infliximab is a chimeric monoclonal antibody that neutralises the biological activity of tumour necrosis factor alpha, a cytokine thought to play an important role in the pathophysiology of sarcoidosis.

CONCLUSION

Our experience using Infliximab adds to the growing evidence that it may fulfil a useful role in cases of refractory neurosarcoidosis.

Leber's hereditary optic neuropathy associated with multiple sclerosis: Harding's syndrome

We describe a 32-year-old woman with sequential, severe, painless visual loss in one eye and then the other, and three temporally distinct episodes of neurological disturbance suggestive of demyelination in the spinal cord. She was positive for the T14484C mutation in the mitochondrial genome, one of three common mutations causing Leber's hereditary optic neuropathy. In addition, MRI identified areas of demyelination within the periventricular white matter of the brain and within the spinal cord. The coexistence of multiple sclerosis and Leber's hereditary optic neuropathy (Harding's syndrome) is known to occur more often than would be expected by chance; therefore, screening for the Leber's mutations in multiple sclerosis patients with severe visual loss should be considered because this has important prognostic and genetic implications.

Cure of disseminated cryptococcal infection in a renal allograft recipient after addition of gamma-interferon to anti-fungal therapy

The immunosuppressive regimens that are used in solid organ transplantation are potent inhibitors of Th0 as well as Th1 and Th2 cell-mediated immune responses. This predisposes patients to disseminated cryptococcal infections. Mortality in such patients remains very high despite advances in anti-fungal chemotherapy. We describe a case of disseminated cryptococcal disease in a renal allograft recipient that failed to respond to prolonged treatment with several anti-fungal drugs. However, addition of the immuno-modulator, interferon-gamma, resulted in the formation of granulomas and the resolution of his disease within 4-6 weeks. As we cannot find a similar example of combination therapy for disseminated cryptococcal disease in the solid organ transplant literature, we propose that interferon-gamma could be used in synergy with anti-fungal drugs to cure disseminated cryptococcal infections in solid organ transplant patients.

Cognition and the inhibitory control of saccades in schizophrenia and Parkinson's disease

Historically, various lines of evidence have converged on the view that the brain expends much of its neural resources on inhibiting its own activity in a critical step towards the cognitive control of behaviour. The loss of inhibitory control is widely reported in neurological and psychiatric disorders; however, the consequences of reduced inhibition in terms of wider cognitive effects on cognitive control operations such as planning, abstract thought, working memory and the ability to appreciate the perspective of others ('theory of mind') has been widely overlooked. The antisaccade paradigm examines the conflict between a prepotent stimulus that produces a powerful urge to fixate the target, and the overriding goal to 'look' in the opposite direction. In this chapter we illustrate how this paradigm is increasingly used to explore the relationship of inhibitory control and cognition in Parkinson's disease, schizophrenia and healthy participants. Evidence is presented that is consistent with the theory of cognitive inhibition as a distinct process that can be dissociated from working memory. We conclude that the inhibitory control of saccadic eye movement should be studied in the wider context of cognitive operations.

Reliable and reproducible LightCycler qPCR for HIV-1 DNA 2-LTR circles

Highly active anti-retroviral therapy (HAART) has reduced the plasma load of HIV-1 to undetectable levels. It has however failed to eliminate the virus from other body compartments. Current methods for monitoring persistent viral replication in HIV-1+ patients require a large amount of blood and/or repeated tissue biopsies. Furthermore, some of the viral reservoirs, such as brain and eye, are inaccessible for sampling. The detection of episomal HIV-1 DNA 2-LTR circles in CD4+ cells is indicative of recent, acute infection events. This paper describes a reliable and reproducible LightCycler-based assay for the quantitative measurement of HIV-1 DNA 2-LTR circles in human peripheral blood mononuclear (PBMN) cells. It details the modifications to the DNA extraction procedure and to the LightCycler PCR procedure that were required to achieve this. This new surrogate marker of persistent viral replication can now be reliably, reproducibly and robustly used to study the clinical progress of large numbers of patients whose plasma HIV-1 RNA has been reduced to undetectable levels by anti-retroviral drugs.

LightCycler qPCR optimisation for low copy number target DNA

The LightCycler is a rapid air-heated thermal cycler which incorporates a fluorimeter for the detection and quantification of Polymerase Chain Reaction (PCR) amplified products. It provides real-time cycle-by-cycle analysis of product generation. Amplification occurs in glass capillary tubes. The products are detected using a fluorescent double stranded DNA binding dye or fluorescent probes. However, conditions that work well in conventional PCR reactions do not readily translate to the LightCycler. Whilst using this new technology to study an infectious pathogen in human tissue samples, several parameters were identified which can have an adverse effect on the reliable and reproducible quantification of low copy number target DNA. They included abstraction of PCR reagents on glass, primer-dimer formation, non-specific product generation, and a failure to amplify low copy number target when it is present in a high background of human chromosomal DNA. For each problem identified, several solutions are described. Novel approaches are also described to ensure that amplification of target DNA and of the quantification standards occurs with the same efficiency. With appropriate changes to the protocols currently in use, LightCycler quantitative Polymerase Chain Reaction (LC-qPCR) can be used to achieve a level of accuracy that exceeds that of an enzyme immunoassay. The LC-qPCR optimisation strategies described are of particular relevance when applying this technology to the study of pathogens in tissue samples. The technique offers the enormous potential for reliable and reproducible quantitative PCR of low copy number target DNA.

Evidence for a post-entry barrier to R5 HIV-1 infection of CD4 memory T cells

BACKGROUND

HIV-1 strains R5 and X4 can infect CD4 memory T cells in vivo. Anti-CD3/28 stimulation induces beta-chemokines and CCR5 down-regulation and renders these cells resistant to R5 HIV-1 infection. Here we describe an additional cellular mechanism that blocks productive R5 HIV-1 infection of CD4 memory T cells.

METHODS

Blood-derived CD4 memory T cells and CD4 T-cell clones were infected with primary R5 and X4 HIV-1 strains. Virus replication was correlated with CCR5 expression and beta-chemokine production. Virus entry and infectivity were measured by PCR for early and late products of HIV reverse transcription respectively.

RESULTS

R5 strains were up to 1000-fold less infectious than X4 viruses for CD4 memory T cells. This resistance was independent of CCR5 levels and of the Delta-32 mutation and the CCR2-V64I/CCR5-59653T linked mutations. Blocking endogenous beta-chemokines relieved minimally this restriction. At the single cell level, CD4 memory cells were either permissive or non-permissive for R5 HIV-1 infection. R5 HIV titre was up to 10-fold lower than X4 virus titre even in a permissive clone. However, R5 viruses replicated as efficiently as X4 viruses in the permissive clone when neutralizing anti-beta chemokine antibodies were added. Non-permissive cells blocked a post-entry step of the virus life-cycle and expressed early but not late HIV transcripts. Neutralizing anti-beta chemokine antibodies promoted R5 virus replication marginally in the non-permissive clone.

CONCLUSION

Some blood memory CD4 T cells retard R5 HIV-1 replication via endogenous beta-chemokines whereas others block productive R5 HIV-1 infection by an additional mechanism that interferes with a post-entry step of the virus life cycle. These natural barriers might contribute to lower pathogenicity of R5 HIV-1 strains for CD4 memory T cells than X4 viruses that emerge late in disease.

Severe Pneumocystis carinii pneumonia increases the infectious titre of HIV-1 in blood and can promote the expansion of viral chemokine co-receptor tropism

AIM

Determine the in vivo effect of Pneumocystis carinii pneumonia (PCP) on: (a) the titre of infectious virus circulating in blood; and (b) the chemokine co-receptor usage of these viruses.

PATIENTS AND METHODS

A longitudinal study of 62 patients over 8 years. The results for PCP were compared with those for disseminated cytomegalovirus (CMV) and acute herpes simplex virus type 1 infections (HSV). Blood was collected every 3-4 months when patients were well, and again when they were acutely ill. A tissue culture based PHA/IL-2 induced HIV replication assay was used to determine the frequency of circulating cells in blood carrying infectious forms of HIV-1. Viral isolates were phenotyped using U87 cells transfected with CD4 and a chemokine co-receptor.

RESULTS

There were 29 cases of PCP, 18 cases of HSV and 11 cases of CMV. A significant increase in the viral replication assay was seen during severe PCP but not during HSV or CMV infections. The number of chemokine co-receptors being used by HIV-1 increased during severe PCP to include CXCR4 and CCR3 in three of six patients from whom viruses were available for detailed study.

CONCLUSIONS

Severe PCP can increase the number of PBMN cells containing integrated, replication competent, infectious forms of HIV-1 circulating in blood. The expanded chemokine co-receptor tropism of these viral isolates could promote the dissemination of HIV-1 from lymphoid to non-lymphoid organs and explain the poor prognosis of patients who develop severe PCP.

Clustered mutations in HIV-1 gag are consistently required for escape from HLA-B27-restricted cytotoxic T lymphocyte responses

The immune response to HIV-1 in patients who carry human histocompatibility leukocyte antigen (HLA)-B27 is characterized by an immunodominant response to an epitope in p24 gag (amino acids 263-272, KRWIILGLNK). Substitution of lysine (K) or glycine (G) for arginine (R) at HIV-1 gag residue 264 (R264K and R264G) results in epitopes that bind to HLA-B27 poorly. We have detected a R264K mutation in four patients carrying HLA-B27. In three of these patients the mutation occurred late, coinciding with disease progression. In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype. In each case, R264K was tightly associated with a leucine to methionine change at residue 268. After the loss of the cytotoxic T lymphocyte (CTL) response to this epitope and in the presence of high viral load, reversion to wild-type sequence was observed. In a fifth patient, a R264G mutation was detected when HIV-1 disease progressed. Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260. Phylogenetic analyses indicated that these substitutions emerged under natural selection rather than by genetic drift or linkage. Outgrowth of CTL escape viruses required high viral loads and additional, possibly compensatory, mutations in the gag protein.

Direct visualization of HIV-1-specific cytotoxic T lymphocytes during primary infection

OBJECTIVE

HIV-specific cytotoxic T lymphocytes (CTL) are believed to play an important role in containing viral replication throughout HIV-1 infection. Previous studies have attempted to quantify the HIV-1-specific CTL precursor frequency during primary HIV infection by using limiting dilution analysis, which almost certainly underestimates the true CTL frequency. Here we use a relatively new technique to quantify HIV-specific CD8 T cells in primary HIV infection.

METHODS

We have used soluble tetrameric complexes of HLA class I molecules complexed with HIV epitope peptides to study the dynamics and frequency of HIV-specific CD8 T cells in relation to plasma viral load in early HIV infection, in three patients with a highly focused HIV-specific CTL response.

RESULTS

We show that the frequencies of HIV-1-specific CD8 T cells in acute infection are significantly higher than previously documented and can be demonstrated well before full seroconversion. These studies also confirm the immunodominance of the B27-restricted response in HIV infection and demonstrate a close temporal relationship between the numbers of circulating HIV-specific CD8 T cells and viral load.

CONCLUSIONS

These findings strongly suggest that HIV-1-specific CD8 T cells are responding directly to the level of viral replication in early HIV infection and are a major factor in its control. In addition, the data indicate that immunodominance for CD8 T-cell responses is established in the acute phase of HIV infection.

Persistence of episomal HIV-1 infection intermediates in patients on highly active anti-retroviral therapy

Treatment of HIV-1-infected individuals with a combination of anti-retroviral agents results in sustained suppression of HIV-1 replication, as evidenced by a reduction in plasma viral RNA to levels below the limit of detection of available assays. However, even in patients whose plasma viral RNA levels have been suppressed to below detectable levels for up to 30 months, replication-competent virus can routinely be recovered from patient peripheral blood mononuclear cells and from semen. A reservoir of latently infected cells established early in infection may be involved in the maintenance of viral persistence despite highly active anti-retroviral therapy. However, whether virus replication persists in such patients is unknown. HIV-1 cDNA episomes are labile products of virus infection and indicative of recent infection events. Using episome-specific PCR, we demonstrate here ongoing virus replication in a large percentage of infected individuals on highly active anti-retroviral therapy, despite sustained undetectable levels of plasma viral RNA. The presence of a reservoir of 'covert' virus replication in patients on highly active anti-retroviral therapy has important implications for the clinical management of HIV-1-infected individuals and for the development of virus eradication strategies.

Reversible alterations in brain metabolites during therapy for disseminated nocardiosis using proton magnetic resonance spectroscopy

We report reversible abnormalities in magnetic resonance spectra acquired from a patient with AIDS undergoing antibiotic and corticosteroid therapy for disseminated nocardiosis, a rare opportunistic infection of immunosuppressed patients which can cause cerebral abscess formation. There was no clinical, CT or MRI evidence of HIV-1 encephalitis. MR spectra were acquired before and after treatment using a two-dimensional chemical shift imaging technique (TR 1500ms, TE 130ms). Prior to treatment, a rise in the choline to creatine ratio and a reduction in the N-acetylaspartate to creatine ratio were observed in MR spectra localized to areas of the left anteromedial centrum semiovale that appeared normal on MR imaging. After 16 weeks, the patient had recovered with complete resolution of the cerebral abscesses on MRI. The MR spectral abnormalities also returned to normal. Two months later, the patient had a relapse with focal neurological signs and further abscesses were demonstrated on MRI of the brain. The patient subsequently died and histopathological and microbiological findings at autopsy confirmed the clinical picture of a recurrence of cerebral nocardiosis with no evidence of HIV-1 encephalitis. This case illustrates reversible MR-measurable metabolite changes in the brain of an HIV-seropositive patient without HIV-1 encephalitis who underwent treatment for cerebral nocardiosis.

Anti-Kaposi's sarcoma and antiangiogenic activities of sulfated dextrins

Delivery of the sulfated polysaccharide dextrin 2-sulfate by the intraperitoneal route to the lymphatic circulation resulted in a clinically significant improvement in Kaposi's sarcoma in three patients. Our in vitro studies show that although sulfated dextrins do not interfere with the growth of isolated human umbilical vein endothelial cells, they do inhibit the morphological differentiation of endothelial cells into tubes as well as reduce new vessel formation in a placental angiogenesis assay. The antiangiogenic effect of dextrin 6-sulfate is greater than that of dextrin 2-sulfate and is independent of their anti-human immunodeficiency virus type 1 activities.

Saccades and smooth pursuit in myotonic dystrophy

Reflexive saccades, remembered saccades, antisaccades, fixation and smooth pursuit were recorded in seven subjects with myotonic dystrophy (MD) and seven age-matched controls using the magnetic scleral search coil technique. Neuropsychological performance was assessed using the Wisconsin Card Sort Test and measures of verbal fluency. Subjects with MD showed significantly elevated error rates in the antisaccade and remembered saccade paradigms, consistent with prefrontal dysfunction, and these two measures of distractibility were significantly correlated with each other. Saccadic latencies, square wave jerk frequency, and smooth pursuit peak velocity gain showed no significant difference between the two groups, although the peak velocity of all classes of saccades was significantly reduced in patients with MD. These results extend the findings of previous studies of oculomotor function in MD, and provide novel evidence for a central contribution to abnormalities of eye movements in this condition.

Pericardial, retroperitoneal, and pleural fibrosis induced by pergolide

Three patients with Parkinson's disease are described who developed pericardial, retroperitoneal, and pleural fibrosis associated with pergolide treatment. Surgical intervention was required in all three cases, either to reach a tissue diagnosis or for potentially life threatening complications. Symptoms emerged on average 2 years after the institution of treatment, and were sufficiently non-specific to cause significant delays in diagnosis in all cases. The erythrocyte sedimentation rate (ESR) was raised in the two patients in whom it was measured. Serosal fibrosis is a rarely reported adverse effect of pergolide treatment, although it is well described with other dopamine agonists. We suggest that patients with Parkinson's disease who receive pergolide treatment should be regularly monitored for the development of such complications.

Remembered saccades with variable delay in Parkinson's disease

The effect of increasing delay on the metrics of remembered saccades was studied in 10 subjects with mild Parkinson's disease, none of whom was receiving treatment with L-dopa, and nine age-matched control subjects. Delays of 1 msec, 250 msec, 1000 msec, 2500 msec, and 5000 msec were used, and reflexive saccades used as a control condition. Results were analyzed for the gain of the primary saccade and the accuracy of the final eye position (FEP gain). Reflexive saccades were normal in subjects with Parkinson's disease, but remembered saccades showed marked hypometria of primary saccade gain at all delays. FEP gain was unimpaired in Parkinson's disease, and primary saccade gain and FEP gain did not vary as a function of delay. Hypometria of primary saccades is compatible with dysfunction in striato-collicular inhibitory pathways in Parkinson's disease, arising as a functional consequence of dopamine deficiency in the basal ganglia. Maintenance of an accurate FEP gain suggests no deficit in oculomotor spatial working memory in Parkinson's disease, at least at delays of up to 5 sec.

1H MR spectroscopy of the brain in HIV-1-seropositive subjects: evidence for diffuse metabolic abnormalities

PURPOSE

To analyze brain metabolite changes in HIV-1-seropositive subjects in order to define whether the neuronal impairment is a localized or more diffuse process.

MATERIALS AND METHODS

15 patients and 18 volunteers underwent multivoxel proton magnetic resonance (MR) spectroscopy at 1.5T. Nine patients were classified as being neuropsychiatrically unimpaired and six as having HIV-1-associated dementia on the basis of a full neuropsychological examination. Spectra were analysed from multiple voxels located in the fronto-parietal cortex and white matter at the level of centrum semiovale.

RESULTS

A significant reduction in mean peak area ratios of NAA/Cr (p<0.005 in the grey matter, p<0.01 in the white matter) and an elevation in mean Cho/Cr (p<0.005 in both grey matter and white matter) were observed in patients with HIV-1-associated dementia when compared to healthy volunteers. No significant metabolite abnormalities were detected in the neuropsychiatrically unimpaired group, although there was a similar trend in the metabolite ratios. The changes in metabolite ratios were of the same order of magnitude in the cortical grey matter and subcortical white matter as in the deeper white matter in all patients. There were also no significant regional variations in mean metabolite ratios between right and left hemispheres or anterior and posterior voxels at the level of the brain studied. There were no abnormalities in Glx/Cr in any spectra analysed from either patient group.

CONCLUSION

The absence of significant regional variation in metabolite ratios at the level of the centrum semiovale provides some evidence that abnormalities of cerebral metabolites in HIV-infected patients may be part of a diffuse process.

Urgent neurology out-patient referrals from primary health care physicians

We retrospectively analysed patients seen in a rapid referral clinic to identify those with abnormalities genuinely requiring urgent assessment, and to evaluate the impact of the clinic on routine services. After advertising the availability of the service, 25% of telephone referrals from primary-care physicians led to identification of patients considered suitable for urgent evaluation. We assessed 350 patients over an 18-month period. After neurological review, relevant abnormalities were identified in 73%, and 33% were considered to have warranted urgent assessment. In addition, 74% required radiological evaluation and 14% had a neurophysiological procedure; 19.4% were admitted on the same day, 13% underwent CSF analysis and 34% required some form of therapeutic intervention. In retrospect, patients with a clinical history of > 11 days rarely warranted urgent referral. Visual failure and diplopia provided the highest correlation with patients deemed to require urgent assessment, and syncope and headache the lowest. Despite the number of patients reviewed, no effect was demonstrated on waiting times for standard out-patient review.

Reduction of the viral load of HIV-1 after the intraperitoneal administration of dextrin 2-sulphate in patients with AIDS

OBJECTIVE

To determine the safety and efficacy of the sulphated polysaccharide, dextrin 2-sulphate, when delivered to the lymphatic circulation by the peritoneal route.

DESIGN

An open Phase I/II dose-escalation clinical study in which six patients with AIDS were treated with seven courses of dextrin 2-sulphate each lasting 1 month.

METHODS

During each course of treatment, the drug was administered daily for 28 days using an intraperitoneal catheter. Viral load was measured at frequent intervals using a plasma tissue culture infectious dose (TCID) assay, a cellular TCID assay, p24 antigenaemia, HIV-1 RNA and HIV-1 DNA. Plasma beta-chemokine levels were also measured.

RESULTS

Dose escalation was completed without toxicity. A total of 7 patient-months of treatment were completed. With increasing doses of dextrin 2-sulphate, the infectious plasma viraemia, cellular viraemia and p24 antigenaemia all fell during the period of drug administration, but with no significant change in HIV-1 RNA. This was associated with increased plasma levels of macrophage inflammatory protein (MIP)-1alpha and MIP-1beta. Dextrin 2-sulphate accumulated in peritoneal macrophages and induced the release of MIP-1alpha and MIP-1beta from these cells in vitro. These beta-chemokines could have augmented the cell surface-mediated anti-HIV-1 effect of dextrin 2-sulphate in vivo by binding to and blocking the CC-chemokine receptor-5. A second fall in infectious plasma viraemia, cellular viraemia, p24 antigenaemia and HIV-1 RNA was seen at day 100 which was then sustained for several months. A clinical improvement in Kaposi's sarcoma was also seen.

CONCLUSIONS

Our results suggest that the intraperitoneal administration of dextrin 2-sulphate can reduce the replication of HIV-1 in patients with AIDS. With increasing doses of dextrin 2-sulphate, the fall in viral load was seen during the period of drug administration and again 2 months after completing treatment.

Cerebral nocardia abscesses in a patient with AIDS: correlation of magnetic resonance and white cell scanning images with neuropathological findings

We present a case of cerebral nocardiosis in a patient with AIDS. Space-occupying lesions were identified using magnetic resonance imaging (MRI) and white cell scanning. Nocardia asteroides was isolated from blood cultures. The patient's response to treatment with amikacin, imipenem and ceftriaxone was followed clinically and radiologically. When he died 6 months later, N. asteroides was isolated at post-mortem from a cerebral abscess. Although cerebral infections associated with the infiltration of neutrophils are rare in patients with AIDS, this case demonstrates that indium-labelled neutrophils can be used to identify a brain abscess and monitor its response to antimicrobial therapy.

Anti-HIV type 1 activity of sulfated derivatives of dextrin against primary viral isolates of HIV type 1 in lymphocytes and monocyte-derived macrophages

The anti-HIV-1 activity of sulfated derivatives of dextrin was tested in activated peripheral blood mononuclear cells and in monocyte-derived macrophages using low-passage syncytium-inducing and non-syncytium-inducing primary viral isolates of HIV-1. All four compounds blocked infection in a dose-dependent manner. Dextrin 2-sulfate blocked infection with a 90% inhibitory concentration (IC90) of 69 microg ml(-1). The IC90 for dextrin 3-sulfate was 50 microg ml(-1) and for dextrin 6-sulfate was 14 microg ml(-1). Increasing the number of sulfate groups to three per glucan molecule (dextrin 2-, 3-, and 6-sulfate) did not reduce the IC90 further (13 microg ml(-1)) compared to dextrin 6-sulfate. There was no significant difference in the concentration required to block infection of activated peripheral blood mononuclear cells when compared with monocyte-derived macrophages, irrespective of whether low-passage syncytium-inducing or non-syncytium-inducing primary viral isolates of HIV-1 were used. Dextrin 2-sulfate and dextrin 6-sulfate also reduced the transmission of HIV-1 in experiments performed using peripheral blood mononuclear cells from HIV-1-positive patients by 6- to 251-fold in a limiting dilution tissue culture infectious dose assay. Sulfated dextrins were not toxic to either primary lymphocytes or macrophages at the concentrations tested. Having previously shown that the cell surface binding of sulfated dextrins is dependent on the position of the negatively charged sulfate groups, we now show that their anti-HIV-1 activity in primary lymphocytes and macrophages is also dependent on the same arrangement. A phase I/II clinical trial of dextrin 2-sulfate is now in progress.

Circular forms of unintegrated human immunodeficiency virus type 1 DNA and high levels of viral protein expression: association with dementia and multinucleated giant cells in the brains of patients with AIDS

Thirty-one histologically abnormal brains from patients with AIDS were studied in order to establish the relationship between multinucleated giant cells, viral protein expression, the various forms of human immunodeficiency virus type 1 (HIV-1) DNA, and clinical evidence of dementia. Unintegrated HIV-1 DNA of 2 to 8 kb was found in 22 of the 31 brains. Multinucleated giant cells without any other pathology were found in 14 cases; unintegrated 1-long terminal repeat (1-LTR) circular forms of HIV-1 DNA and strongly positive immunohistochemistry for gp41 and p24 were found in most of these brains. Most of these patients had a clinical diagnosis of HIV-1-associated dementia and cerebral atrophy. In all the other brains studied, 1-LTR circles were absent and immunohistochemistry for gp41 and p24 was usually negative. Very few of these patients had a clinical diagnosis of dementia. Sequence comparison of the LTR region from integrated HIV-1 DNA with that from unintegrated 1-LTR circular forms of HIV-1 DNA in 12 cases showed no significant differences. A further comparison of these brain-derived LTR sequences with LTR sequences derived directly from lymphoid tissue also showed strong sequence conservation. The V3 loop of the virus from the brain was sequenced in 6 cases and had a non-syncytium inducing-macrophage-tropic genotype. Our results show that (i) although unintegrated HIV-1 DNA was present in most brains from patients with AIDS, molecular evidence of high levels of viral replication was associated with the presence of multinucleated giant cells and dementia, and that (ii) the HIV-1 LTR is not a determinant of neurotropism. These observations suggest that replication of HIV-1 and not just the presence of HIV-1 DNA within giant cells makes the important contribution to central nervous system damage.

Abnormalities of predictive saccades in Parkinson's disease

Saccades of patients with mild Parkinson's disease (PD) are said to be abnormal in the absence of a concurrently visible target or when they are part of a rapid sequence of eye movements. We tested this hypothesis using a predictive saccade paradigm in which target visibility is withdrawn for a period. Three rates of target alternation were used (0.25 Hz, 0.5 Hz and 1.0 Hz). Withdrawal of target visibility brought out the extremes of primary saccade gain for both the controls and the patients with PD, most undershoot being displayed at the lowest frequency, whereas the gain was greatest at the highest frequency, actually overshooting the target location. These results demonstrate that the spatial error of parkinsonian saccades does not invariably take the form of hypometria when part of a rapid sequence of eye movements.