How can drug discovery for psychiatric disorders be improved?

Psychiatric disorders such as depression, anxiety and schizophrenia are leading causes of disability worldwide, and have a huge societal impact. However, despite the clear need for better therapies, and major advances in the understanding of the molecular basis of these disorders in recent years, efforts to discover and develop new drugs for neuropsychiatric disorders, particularly those that might revolutionize disease treatment, have been relatively unsuccessful. A multidisciplinary approach will be crucial in addressing this problem, and in the first Advances in Neuroscience for Medical Innovation symposium, experts in multiple areas of neuroscience considered key questions in the field, in particular those related to the importance of neuronal plasticity. The discussions were used as a basis to propose steps that can be taken to improve the effectiveness of drug discovery for psychiatric disorders.

Variation in the gene encoding the serotonin 2A receptor is associated with outcome of antidepressant treatment

Depressive disorders account for a large and increasing global burden of disease. Although the condition of many patients improves with medication, only a minority experience full remission, and patients whose condition responds to one medication may not have a response to others. Individual variation in antidepressant treatment outcome is, at present, unpredictable but may have a partial genetic basis. We searched for genetic predictors of treatment outcome in 1,953 patients with major depressive disorder who were treated with the antidepressant citalopram in the Sequenced Treatment Alternatives for Depression (STAR*D) study and were prospectively assessed. In a split-sample design, a selection of 68 candidate genes was genotyped, with 768 single-nucleotide-polymorphism markers chosen to detect common genetic variation. We detected significant and reproducible association between treatment outcome and a marker in HTR2A (P range 1 x 10(-6) to 3.7 x 10(-5) in the total sample). Other markers in HTR2A also showed evidence of association with treatment outcome in the total sample. HTR2A encodes the serotonin 2A receptor, which is downregulated by citalopram. Participants who were homozygous for the A allele had an 18% reduction in absolute risk of having no response to treatment, compared with those homozygous for the other allele. The A allele was over six times more frequent in white than in black participants, and treatment was less effective among black participants. The A allele may contribute to racial differences in outcomes of antidepressant treatment. Taken together with prior neurobiological findings, these new genetic data make a compelling case for a key role of HTR2A in the mechanism of antidepressant action.

Effects of tryptophan depletion on serum levels of brain-derived neurotrophic factor in unmedicated patients with remitted depression and healthy subjects

OBJECTIVE

Data suggest the involvement of serotonergic and neurotrophic systems in major depressive disorder. To investigate their potential interaction, the authors studied changes in serum levels of brain-derived neurotrophic factor (BDNF) during tryptophan depletion and sham depletion in unmedicated patients with remitted major depressive disorder and in a group of healthy comparison subjects.

METHOD

Twenty-seven patients with remitted major depressive disorder and 20 healthy subjects underwent tryptophan depletion and sham depletion in a randomized, placebo-controlled, double-blind crossover study. Serum BDNF concentrations and plasma tryptophan concentrations as well as behavioral assessments were obtained.

RESULTS

During tryptophan depletion, BDNF levels increased in healthy volunteers. By contrast, patients with remitted major depressive disorder were unable to mount this presumed compensatory response, and BDNF levels remained low in these patients.

CONCLUSIONS

The results further substantiate the potential role of BDNF in major depressive disorder.

Sympathoneural and adrenomedullary functional effects of ??2C-adrenoreceptor gene polymorphism in healthy humans

OBJECTIVES

alpha2-Adrenoreceptors restrain sympathetic nervous outflows and inhibit release of noradrenaline from sympathetic nerves. In-frame deletion of the alpha2C-adrenoreceptor subtype (alpha2CDel322-325) increases the risk of congestive heart failure. Increased delivery of catecholamines to cardiovascular receptors might explain this increased risk.

METHODS

Twenty-nine healthy African-Americans genotyped for alpha2-adrenoreceptor subtype polymorphisms underwent 3H-noradrenaline and 3H-adrenaline intravenous infusion and arterial blood sampling for measurements of rates of entry of endogenous noradrenaline and adrenaline into arterial plasma (total body spillovers) by the tracer dilution technique. Eleven subjects were homozygotes for the alpha2CDel322-325 polymorphism, nine heterozygotes, and nine non-carriers. Subjects were studied during supine rest and during and after i.v. infusion of the alpha2-adrenoreceptor antagonist, yohimbine.

RESULTS

At rest, homozygotes for the alpha2CDel322-325 polymorphism had higher total body noradrenaline spillover than did heterozygotes (t=2.90, df=18, P=0.023) or non-carriers (t=3.22, df=18, P=0.010). Adrenaline spillover was higher in homozygotes than non-carriers (t=2.61, df=18, P=0.045). Administration of yohimbine produced larger, more sustained increments in noradrenaline spillover, heart rate, and anxiety in homozygotes than in the other groups.

CONCLUSION

In healthy people, alpha2CDel322-325 polymorphism is associated with increased sympathetic nervous and adrenomedullary hormonal activities, both during supine rest and during pharmacologically evoked catecholamine release. Polymorphisms of the alpha2C-adrenoreceptor may help explain individual differences in predisposition to a variety of disorders of catecholaminergic function, such as cardiovascular disorders, depression or anxiety disorders.

Unusual muscle disease in HIV infected patients

Two patients presented with proximal muscle weakness, a normal or minor elevation of creatine phosphokinase (CPK) and normal findings on electromyography. Muscle biopsy in one patient revealed CD8+ polymyositis, and in the other showed ddI induced myopathy. These cases illustrate the importance of muscle biopsy in identifying the underlying pathology in HIV infected patients with muscle weakness and little or no abnormality in laboratory investigations.

[Possible involvement of protein kinase C in the pathophysiology and treatment of bipolar disorder]

Over the past decade, the focus of research into the pathophysiology of bipolar disorder has shifted from an interest in the biogenic amines to an emphasis on second messenger systems within cells. Emerging evidence implicates protein kinase C (PKC) intracellular signaling cascade in the pathophysiology and treatment of bipolar disorder. This review explores the possible involvement of PKC in bipolar disorder summarizing results from laboratory and clinical studies. Bipolar patients were demonstrated to have altered PKC levels, activity or distribution in platelets and in the brain. Chronic administration of lithium and valproate produced a striking reduction in protein kinase C (PKC) human cells and in rats. PKC inhibition in animals resulted in altered affective-like behavior and in a small study, tamoxifen (a PKC inhibitor) had marked antimanic efficacy. The results of studies at the molecular, cellular, animal and clinical levels all suggest that regulation of PKC signaling pathways may play a major part in the pathophysiology and treatment of bipolar disorder. Therefore, this pathway may be a promising candidate for the development of new, more specific drugs for the disease.

Genomewide linkage analyses of bipolar disorder: a new sample of 250 pedigrees from the National Institute of Mental Health Genetics Initiative

We conducted genomewide linkage analyses on 1,152 individuals from 250 families segregating for bipolar disorder and related affective illnesses. These pedigrees were ascertained at 10 sites in the United States, through a proband with bipolar I affective disorder and a sibling with bipolar I or schizoaffective disorder, bipolar type. Uniform methods of ascertainment and assessment were used at all sites. A 9-cM screen was performed by use of 391 markers, with an average heterozygosity of 0.76. Multipoint, nonparametric linkage analyses were conducted in affected relative pairs. Additionally, simulation analyses were performed to determine genomewide significance levels for this study. Three hierarchical models of affection were analyzed. Significant evidence for linkage (genomewide P<.05) was found on chromosome 17q, with a peak maximum LOD score of 3.63, at the marker D17S928, and on chromosome 6q, with a peak maximum LOD score of 3.61, near the marker D6S1021. These loci met both standard and simulation-based criteria for genomewide significance. Suggestive evidence of linkage was observed in three other regions (genomewide P<.10), on chromosomes 2p, 3q, and 8q. This study, which is based on the largest linkage sample for bipolar disorder analyzed to date, indicates that several genes contribute to bipolar disorder.

Support of retinal ganglion cell survival and axon regeneration by lithium through a Bcl-2-dependent mechanism

PURPOSE

To explore whether lithium, a long-standing mood-stabilizing drug, can be used to induce expression of Bcl-2 and support the survival and regeneration of axons of retinal ganglion cells (RGCs).

METHODS

Levels of expression of Bcl-2 in the retina were assessed with quantitative reverse transcription-polymerase chain reaction. To determine whether lithium directly supports the survival of and axon-regenerative functions of RGCs, various amounts of lithium were added to cultures of isolated RGCs. Anti-Thy1.2 antibodies-conjugated to magnetic beads were used to isolate the RGCs. In addition, retina-brain slice cocultures were prepared from tissues of Bcl-2-deficient or Bcl-2-transgenic mice and treated with various amounts of lithium. The effects of the expression of Bcl-2 on lithium-mediated functions were then analyzed.

RESULTS

Normal mouse retina expressed very low levels of Bcl-2 after birth. Addition of lithium in the culture increased mRNA levels of Bcl-2 in retinas of postnatal mice in a dose-dependent manner. Moreover, lithium promoted not only the survival of RGCs but also the regeneration of their axons. Depleting or forcing the expression of Bcl-2 in RGCs eliminated the effects of lithium.

CONCLUSIONS

Lithium supports both the survival and regeneration of RGC axons through a Bcl-2-dependent mechanism. This suggests that lithium may be used to treat glaucoma, optic nerve neuritis, the degeneration of RGCs and their nerve fibers, and other brain and spinal cord disorders involving nerve damage and neuronal cell loss. To achieve full regeneration of the severed optic nerve, it may be essential to combine lithium therapy with other drugs that mediate induction of a permissive environment in the mature central nervous system.

Peripheral neuropathy in patients with HIV infection: consider dual pathology

Two HIV infected patients presented with peripheral neuropathy, in one patient this was originally ascribed to HIV associated mononeuritis multiplex and in the other to stavudine. Investigations confirmed these diagnoses and in both cases genetic analysis identified a second hereditary aetiology: in the first patient hereditary neuropathy with liability to pressure palsies and in the second hereditary motor and sensory neuropathy.

Preclinical models: status of basic research in depression

Approximately one half-century ago several classes of medications, discovered by serendipity, were introduced for the treatment of depression and bipolar disorder. These highly effective medications revolutionized our approach to mood disorders and helped launch the modern era of psychiatry. Yet our progress since those serendipitous discoveries has been disappointing. We still do not understand with certainty how those medications produce their desired clinical effects. We have not introduced newer medications with fundamentally different mechanisms of action than the older agents. We have not identified the genetic and neurobiological mechanisms underlying depression and mania, nor do we understand the mechanisms by which nongenetic factors influence these disorders. We have only a rudimentary understanding of the circuits in the brain responsible for the normal regulation of mood and affect, and of those circuits that function abnormally in mood disorders. In approaching these gaps in our knowledge, this workgroup highlighted four major areas for future investment. These include developing better animal models of mood disorders; identifying genetic determinants of normal and abnormal mood in humans and animals; discovering novel targets and biomarkers of mood disorders and treatments; and increasing the recruitment of investigators from diverse backgrounds to mood disorders research.

Varicella zoster virus-associated neurological disease in HIV-infected patients

Varicella zoster virus (VZV) is an uncommon but well recognized cause of neurological disease in HIV-infected patients. Analysis of cerebrospinal fluid (CSF) using the polymerase chain reaction (PCR) in HIV-infected patients presenting with neurological disease has increasingly allowed diagnosis of VZV-associated pathology. We report clinical, radiological and virological data from 15 consecutive patients with VZV-associated neurological disease. Clinical presentation was varied, including meningo-encephalitis in 9 and isolated cranial nerve palsies in 6. VZV deoxyribonucleic acid (DNA) was detected by PCR in CSF of 11/15; pleocytosis was present in only 6/15, raised protein in 11/15. Magnetic resonance imaging (MRI) appearances were focal signal abnormalities in 8, meningeal enhancement in 2 and normal in 2. With specific anti-VZV therapy 10 patients recovered fully. The predictive value of PCR on CSF for diagnosis of VZV-associated neurological disease should take into account the patient's clinical presentation, concurrent infections and response to anti-VZV therapy.

Neuropathy in HIV infection

Peripheral nerve complications in patients infected with HIV usually result from the virus itself, or are due to some of the antiretroviral drugs (zalcitabine, didanosine or stavudine). It may be difficult to distinguish between these two aetiologies on clinical or neurophysiological criteria. Since they are a significant cause of morbidity, a number of studies have looked at agents used for symptomatic control. More recently, there has been a focus on treatments that improve nerve function, including recombinant human nerve growth factor and the reduction of HIV viral load with antiretroviral drugs.

Epilepsy surgery, visual fields, and driving: a study of the visual field criteria for driving in patients after temporal lobe epilepsy surgery with a comparison of Goldmann and Esterman perimetry

Twenty four patients who had undergone temporal lobe surgery for epilepsy were assessed to determine (a) whether or not they had developed a visual field defect and (b) if a field defect was present, were the visual field criteria, as required by the DVLA, fulfilled using the monocular Goldmann perimeter test and the automated binocular Esterman method performed on a Humphrey perimeter. A field deficit was found in 13 of 24 (54%) using the Goldmann perimeter and 11 of 24 (46%) by the Esterman method. The second was a more lenient assessment with six of 24 (25%) failing the driving criteria compared with 10 of 24 (42%) by the monocular Goldmann method. Three patients were seizure free but failed the driving criteria. This complication of surgery for temporal lobe epilepsy needs to be discussed with patients before surgery.

Chronic inflammatory demyelinating polyradiculoneuropathy: a prevalence study in south east England

Although there are now widely accepted diagnostic criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) there are few epidemiological data. A prevalence study was performed in the four Thames health regions, population 14 049 850. The prevalence date was 1 January 1995. Data were from a national consultant neurologist surveillance programme and the personal case series of two investigators. A diagnosis of CIDP was made according to definite, probable, possible, or suggestive diagnostic criteria. A wide difference in prevalence rates between the four health regions was noted, probably due to reporting bias. In the South East Thames Region, from which the data were most comprehensive the prevalence for definite and probable cases was 1.00/100 000; the highest total prevalence (if possible and suggestive cases were included) would have been 1.24/100 000. On the prevalence date 13% of patients required aid to walk and 54% were still receiving treatment.

Status dystonicus: the syndrome and its management

Patients with dystonic syndromes sometimes develop increasingly frequent and relentless episodes of devastating generalized dystonia which we call status dystonicus. Twelve cases of status dystonicus, of various underlying aetiologies, are presented. Possible precipitating factors were identified in only five cases: intercurrent infection (one); discontinuation of lithium (one) and tetrabenazine (one); and the introduction of clonazepam (two). Nine patients required mechanical ventilation and three others were sedated with intravenous chlormethiazole. Drug therapy used included benzhexol, tetrabenazine, pimozide, baclofen, chlorpromazine, haloperidol, carbamazepine and acetozolamide. Two patients underwent thalamotomies, one of whom improved. Two patients died, five returned to their pre-status dystonicus condition, two eventually made a full recovery and three were worse. Patients with status dystonicus should be managed on an intensive care unit as they may develop bulbar and respiratory complications which may require ventilation. Metabolic problems encountered can include rhabdomyolysis with acute renal failure. Drug therapy with benzhexol, tetrabenazine and pimozide or haloperidol may be beneficial in some cases.

A naturally occurring amino acid substitution of the human serotonin 5-HT2A receptor influences amplitude and timing of intracellular calcium mobilization

Recently, two naturally occurring amino acid substitutions were identified in the C-terminal region of the serotonin 5-HT2A receptor. One of these, His452Tyr, has a rarer allele Tyr frequency of 9%. If 452Tyr alters 5-HT2A function, it would thus be a candidate allele for human neurobehavioral variation. The present study was designed to evaluate the potential influence of the 452His and 452Tyr alleles on cellular 5-HT2A functions. Platelet 5-HT2A binding and 5-HT-induced Ca2+ response were compared in eight 452His/452His homozygous and eight 452His/452Tyr heterozygous individuals matched for sex, age, and diagnosis (all were patients with seasonal affective disorder). There was no difference in 5-HT2A binding measured using 125I-lysergic acid diethylamide. Nor were levels of G-protein subunits or PKC alpha, delta, epsilon, or zeta significantly altered. However, when Ca2+ response was stimulated by 2, 5, 10, or 25 microM 5-HT, significant differences were found. In 452His/452Tyr heterozygotes, 452Tyr was associated with both smaller peak amplitude in Ca2+ mobilization and a different time course of response, with slower peak latency and longer half-time in 452His/452Tyr heterozygotes compared with 452His/452His homozygotes. The overall difference in the response of the 5-HT2A receptor in individuals with 452Tyr was a blunting of the shape of the Ca2+ mobilization peak. The data reported here suggest that the primary sequence of this intracellular domain is important in function of the receptor and that the 452His and 452Tyr 5-HT2A alleles should be carefully evaluated for effects on human neurobehavioral variation.

Guanine nucleotide binding proteins in opioid-dependent patients

Guanine nucleotide binding (G) protein levels and functioning in the platelets of 19 methadone-maintained patients were compared to age and sex matched, normal controls. We found that in the methadone patients, G alpha s-levels were significantly higher, while the levels of G alpha i 1/2 and pertussis toxin catalyzed [32P]ADP ribosylation were significantly lower compared to control subjects in platelet membranes. We have further found that when all three of these biochemical indicators were combined in a discriminant function analysis, 79% of the methadone patients were correctly classified and 83% of the controls were correctly classified.

Progressive myoclonic ataxia associated with coeliac disease. The myoclonus is of cortical origin, but the pathology is in the cerebellum

We report four patients with a progressive myoclonic ataxic syndrome and associated coeliac disease. The onset of the neurological syndrome followed the gastrointestinal and other manifestations of coeliac disease while on a gluten-free diet, in the absence of overt features of malabsorption or nutritional deficiency. The condition progressed despite strict adherence to diet. The neurological syndrome was dominated by action and stimulus sensitive myoclonus of cortical origin with mild ataxia and infrequent seizures. Plasmapharesis and immunosuppressive treatment were tried in two patients but were not beneficial. Post-mortem examination of the brain in one case showed selective symmetrical atrophy of the cerebellar hemispheres with Purkinje cell loss and Bergmann astrocytosis, and with preservation of the cerebral hemispheres and brainstem. Coeliac disease should be considered in the differential diagnosis of all patients presenting with a progressive myoclonic ataxic syndrome.

Neurophysiological assessment of peripheral nerve and spinal cord function in asymptomatic HIV-1 infection: results from the UCMSM/Medical Research Council neurology cohort

As part of the Medical Research Council prospective study of the neurological complications of HIV infection, neurophysiological tests of spinal cord and peripheral nerve function were recorded in a cohort of homosexual or bisexual men. The studies included motor and sensory nerve conduction studies, vibration perception thresholds, somatosensory evoked potentials and motor evoked potentials elicited by magnetic stimulation. The results were compared with markers of immune function. The findings from 114 volunteers were analysed in a cross-sectional study. Fifty-nine were HIV-seropositive but asymptomatic, 26 had progressed to the symptomatic stages of HIV disease and 29 were persistently HIV-seronegative. There was some evidence of a mild sensory axonopathy in the symptomatic HIV-seropositive group. No differences were detected between the asymptomatic HIV-seropositive group and the HIV-seronegative comparison group. There were no consistently significant correlations between the neurophysiological measurements and CD4 counts and beta 2-microglobulin levels. On repeated testing, there was no evidence of a trend towards deterioration over a mean period of approximately 3 years in 36 HIV-seropositive subjects who remained asymptomatic compared with 22 HIV-seronegatives. These findings have failed to demonstrate neurophysiological evidence of spinal cord or peripheral nerve dysfunction in the asymptomatic stages of HIV infection.

Cortical and subcortical JC virus infection: two unusual cases of AIDS associated progressive multifocal leukoencephalopathy

Two patients with AIDS and progressive neurological syndromes had necropsies that identified JC virus infection of the cerebral or cerebellar cortex. The unusual presentation of progressive multifocal leukoencephalopathy with grey matter involvement and normal cerebral imaging is discussed.

The effects of prolonged lithium exposure on the immune system of normal control subjects: serial serum soluble interleukin-2 receptor and antithyroid antibody measurements

The purpose of this study was to begin evaluating the effects of lithium carbonate on in vivo immune function in normal controls. We postulated that lithium carbonate would stimulate lymphocytes but would not affect the production of antithyroid antibodies. Twenty-seven normal controls had blood samples drawn for measurements of serum soluble interleukin-2 receptors (SIL-2Rs), antithyroglobulin antibodies, and antimicrosomal antibodies prior to and after approximately 1 and 4 weeks of treatment with lithium carbonate at therapeutic blood levels. Subjects had a small but statistically significant increase in serum SIL-2Rs after 4 weeks of lithium treatment (446.3 +/- 177.2 U/ml versus 497.6 +/- 232.3 U/ml, p = 0.033). There was no increase in the prevalence of antithyroglobulin or antimicrosomal antibodies with lithium treatment nor did lithium act as an adjuvant to increase the titers in subjects with preexisting antithyroid antibodies.

Serial MRI of the brain in asymptomatic patients infected with HIV: results from the UCMSM/Medical Research Council neurology cohort

Seventy-six homosexual or bisexual men underwent two cranial MRI studies at a mean interval of 13 months; 23 were HIV seronegative, 41 seropositive but asymptomatic (Center for Disease Control (CDC) groups II/III), and 12 had AIDS related complex (ARC)/AIDS (CDC group IV). Agreement between two neuroradiologists was rated as very good for assessment of enlargement of ventricles and good for widening of cerebral sulci and the presence of focal lesions. For assessment of serial studies, the agreement was moderate. The prevalence of cerebral atrophy and focal white matter lesions was no higher in the asymptomatic patients (CDC group II/III) than in appropriate seronegative controls. Some patients with ARC/AIDS showed evidence of developing cerebral atrophy during the study period when serial scans were compared. The imaging evidence supports the other data obtained from this cohort, which suggest that no significant CNS involvement occurs in HIV infection before the development of ARC/AIDS.

Long-latency event-related potentials in asymptomatic human immunodeficiency virus type 1 infection

As part of the Medical Research Council prospective study of the neurological and neuropsychological complications of human immunodeficiency virus (HIV) infection, long-latency event-related potentials were recorded in a cohort of homosexual and bisexual men. The latencies and amplitudes of the potentials, recorded from three scalp sites, were compared with the scores from neuropsychological tests of memory, attention, and concentration and with markers of immune function. The findings from 94 men were analyzed in the cross-sectional study of whom 47 were HIV seropositive without symptoms or signs of HIV type 1 (HIV-1) infection, 24 had progressed to the symptomatic stages of the disease, and 23 were persistently HIV seronegative. There were no consistently significant differences between the three subject groups in mean latencies and amplitudes of the P300 and N200 or in the numbers of abnormal P300 latencies. There were no significant correlations between either the neuropsychological tests scores or the immune measures (CD4 lymphocyte count and beta 2 microglobulin level) and the neurophysiological parameters. On repeated testing an average of 2 years later, there was no evidence of a significant trend towards deterioration in 30 HIV-seropositive subjects who remained asymptomatic compared with 22 HIV seronegatives. These findings indicate that there is no neurophysiological evidence of cognitive dysfunction in the asymptomatic stages of HIV-1 infection.

Effects of chronic lithium treatment on platelet PKC isozymes in Alzheimer's and elderly control subjects

Patients with Alzheimer's disease (AD) have been reported to have abnormalities in peripheral cells similar to some of those found in the brain, including decreased levels of protein kinase C (PKC) in fibroblasts. Since increasing evidence suggests that lithium affects PKC function, we investigated the effects of 3 weeks of lithium administration on the immunolabeling of 4 PKC isozymes (alpha, beta, epsilon, and zeta) in particulate and soluble fractions from platelets of 7 patients with probable AD and 6 age-matched controls. AD patients had significantly less particulate or membrane-associated PKC zeta than normals during the placebo phase (P < 0.003). After 3 weeks of lithium treatment, AD patients had significantly less membrane-associated PKC alpha (P < 0.002), epsilon (P < 0.003), and zeta (P < 0.001) than normals. This is the first report of a difference in PKC in blood cells between AD and control subjects. These findings appear to indicate that some PKC isozymes may be differentially regulated in AD versus elderly controls, at least as evidenced in this peripheral cellular system.

Muscle disease, HIV and zidovudine: the spectrum of muscle disease in HIV-infected individuals treated with zidovudine

Eleven patients with AIDS or AIDS-related complex who developed muscle-related symptoms whilst taking zidovudine were investigated. The clinical details of a further ten patients who did not undergo muscle biopsy are also outlined. The clinical features, quantitative muscle strength testing, electromyographic findings, serial creatine kinase levels, muscle biopsy appearance on light microscopy and the effects of zidovudine withdrawal and rechallenge are described. The spectrum of muscle disease encountered included four cases of frank myopathy diagnosed using clinical, electrophysiological and histological criteria, four patients with mild weakness and myalgia in whom muscle biopsies were normal, three patients with myalgia only and a mild increase in the interstitial cell infiltrate shown by biopsy. The patients presenting with myopathy showed no improvement on withdrawal of zidovudine but responded to immunosuppressive therapy with steroids and, in one case, thalidomide prescribed incidentally. At present, it is not yet possible to clinically define a specific zidovudine-induced myopathy that is distinct from the other effects of HIV infection on muscle structure and function. Our experience suggests that zidovudine may be implicated as a myotoxin in some patients, particularly those with myalgia and mild weakness. In those patients with severe weakness, and with biopsy findings of necrosis and inflammation, the drug effects may be difficult to separate from the primary effects of HIV.

Optic neuritis and HIV-1 infection

A patient is reported who developed acute optic neuritis in the context of severe immunodeficiency associated with HIV-1 infection. The clinical, laboratory, and radiological features are described and the possible associations with syphilis, multiple sclerosis, lymphoma, and HIV-1 infection are discussed.

Mood and psychiatric disturbance in HIV and AIDS: changes over time

A sample of 26 HIV seronegative, 59 HIV seropositive asymptomatic and 7 HIV seropositive symptomatic homosexual and bisexual men were assessed over two visits, a mean of 11 months apart, using the BDI, STAI, and CIS. Significant differences emerged between the symptomatic group and the other two groups. Past psychiatric history and the somatic items in the assessments accounted for some of these differences. The seropositive asymptomatic and the seronegative groups did not differ on any of the mood or psychiatric assessments, suggesting minimal effect on psychological well-being of seroconversion in the absence of symptoms.

The pathology of the posterior root ganglia in AIDS and its relationship to the pallor of the gracile tract

The spinal cord and the thoracic and lumbar posterior root ganglia (PRGs) of 14 HIV-positive men and 7 age- and sex-matched controls were studied by routine histology, morphometric analysis of the number of nodules of Nageotte (nN) and the diameters of sensory ganglion cells, immunohistochemistry and in situ hybridization. In 7 patients (2 of whom had evidence of cytomegalovirus ganglionitis) there were increased numbers of nN and diffuse, mild infiltration with CD45R+ T lymphocytes; no B lymphocytes were observed. Macrophages were increased in number in all cases. Whenever more than one ganglion was examined from the same patient, the appearances were similar in all. There was no alteration in the distribution of ganglion cell diameters. Changes in the spinal cord included vacuolar myelopathy (5 cases), HIV myelitis (1 case), microglial nodules (3 cases) and pallor of the gracile tracts (GTP) in 7 cases, in 6 of whom it co-existed with increased numbers of nN. Seven cases had no abnormalities, except the increase in number of macrophages in PRGs. In spite of a correlation between sensory nerve cell loss and GTP our findings suggest that other mechanisms, such as 'dying back' may contribute to the pathogenesis of GTP. Moreover, sensory disturbances were found most commonly in association with nerve cell loss; however, loss of sensory ganglion cells was not necessarily associated with evidence of sensory impairment.

Neurological and neuropsychological performance in HIV seropositive men without symptoms

Ninety five HIV seropositive and 32 seronegative homosexual men were recruited to a prospective study of the early features and natural history of the neurological manifestations of HIV infection. There was no evidence from the initial neurological examination, a neuropsychological test battery, nerve conduction studies, somatosensory evoked potentials from the legs, P300 event related auditory evoked potentials, magnetic stimulation of the motor cortex, or MRI scans that HIV infected men without symptoms in CDC groups II/III differed significantly from a well matched seronegative comparison group. Only the subgroup in CDC IV showed evidence of impairment, and this was restricted to their performance on some of the cognitive tests. The results imply that, despite early invasion of the CNS by HIV, major disturbances of function manifest themselves only when the patient becomes immunosuppressed. The importance of an appropriate comparison group and awareness of the potentially confounding influences such as age, education, exposure to alcohol and drugs, and mood and anxiety in such studies is stressed. The essentially negative findings are important in the understanding of the pathogenesis of neurological effect in HIV infection and in the design and interpretation of therapeutic trials.

Neurosarcoidosis--demonstration of meningeal disease by gadolinium enhanced magnetic resonance imaging

Arriving at a firm diagnosis of neurosarcoidosis continues to pose serious problems, particularly when evidence of granulomatous disease outside the nervous system is lacking. The commonest mode of presentation of neurosarcoidosis is with cranial nerve palsies. Two cases of presumed neurosarcoidosis with cranial nerve palsies showed clear evidence of focal meningeal disease on gadolinium-DTPA enhanced MRI brain scans. Although not specific for sarcoidosis, this technique may be very useful in aiding the diagnosis in suspected cases.

Lambert Eaton syndrome: autonomic neuropathy and inappropriate antidiuretic hormone secretion in a patient with small cell carcinoma of the lung

A patient with small cell carcinoma of the lung developed asymptomatic autonomic neuropathy, inappropriate antidiuretic hormone (ADH) secretion and Lambert Eaton myasthenic syndrome. The autonomic neuropathy and inappropriate ADH secretion were present at the time of diagnosis of the tumour. Following chemotherapy these resolved, but 5 months later the patient developed Lambert Eaton syndrome which responded to 3,4-diaminopyridine. This sequence of changes appears to be unique.

Haemophilus influenzae lobar pneumonia in the father of a child with epiglottitis

We present a case of Haemophilus influenzae lobar pneumonia in the father of a child admitted with acute epiglottitis caused by the same organism. The suggestion that adult, as well as child, contacts for Haemophilus influenzae epiglottitis should be prophylactically treated is discussed.

Haemophilus influenzae lobar pneumonia in the father of a child with epiglottitis

We present a case of Haemophilus influenzae lobar pneumonia in the father of a child admitted with acute epiglottitis caused by the same organism. The suggestion that adult, as well as child, contacts for Haemophilus influenzae epiglottitis should be prophylactically treated is discussed.

Calcific constrictive pericarditis due to rheumatoid arthritis

A patient with calcific constrictive pericarditis due to rheumatoid arthritis is presented: the literature reveals only one previous case which was attributed to the long duration of the rheumatoid arthritis.