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Biomedical subjects

R J Guiloff

Publications and source records attributed to R J Guiloff.

At least 37 records · Page 2Linked to original sources
PubMed1992

Voluntary activation and fiber density of fasciculations in motor neuron disease.

Two hundred voluntarily activated motor units and 211 fasciculations were recorded in the biceps of 10 patients with motor neuron disease with the Macro EMG technique. Twenty-two fasciculations, in nine of 10 muscles, had a potential of closely similar shape, amplitude, and area to that of a voluntary unit. Fasciculating units that could not be activated voluntarily had a higher mean number of spikes in their triggering single fiber potentials than units that could only be activated voluntarily, but statistically similar Macro EMG parameters. The mean number of single fiber spikes, and Macro EMG parameters, of fasciculations activated voluntarily, were similar to those of units that were only activated voluntarily. A positive correlation between fiber density and Macro EMG median amplitude and area in individual patients, and between number of single fiber spikes and Macro EMG amplitudes and areas in the pooled data, was found for fasciculations but not for voluntary units. At least 10% of fasciculations in patients with motor neuron disease may originate near or above the point of axonal branching and a proportion of those without evidence of voluntary activation may have a higher number of smaller muscle fibers, or more closely packed muscle fibers, of similar or greater size, than voluntarily activated motor units. Differences in the peripheral microanatomy of a number of fasciculation units not activated voluntarily may underlie ectopic impulse generation in the terminal axonal arborization, endplate zone, or muscle fibers of these units.

Electromyography↗
PubMed1992

Central nervous system opportunistic infections in HIV disease: clinical aspects.

Nervous system opportunistic infections are seen in about one fifth of AIDS cases and account for over 40% of the patients with neurological manifestations. Serious infections are seen in severely immunosuppressed patients, usually with CD4 counts of 200 ml-1 or less. The commonest is CMV, which can produce acute encephalitis, sometimes with focal hemisphere or brain-stem signs, dementia, retinitis, optic neuritis and an ascending radiculomyeloencephalitis. Cryptococcal meningitis is the most frequent fungal disease; a high degree of clinical suspicion is required in patients with fever, malaise, headache or seizures. Only CSF cultures are always positive; both serum and CSF cryptococcal antigen tests are highly sensitive and specific. Treatment with amphotericin B and flucytosine is successful in at least 70% of first episodes but side-effects are common. Without maintenance therapy 50% of patients relapse; fluconazole is recommended. Cerebral toxoplasmosis can present with focal cerebral or spinal cord signs but also as a diffuse encephalopathy; negative T. gondii serology is exceptional but positive serum titres are usually unhelpful. Treatment with sulfadiazine, pyrimethamine and folinic acid achieves good results in 90% of the first episodes, but side-effects are common. Appearances on CT scan or MRI may take several weeks to improve. The value of an empirical approach to treatment is well-established; an initial cerebral biopsy is difficult to justify. Without maintenance therapy a relapse rate of 50% can be expected; therapy with sulfadiazine and pyrimethamine may also prevent pneumocystosis. HIV disease appears to increase the likelihood of neurosyphilis, and the risk of relapse after conventional penicillin doses, in patients with syphilis; at least 3-4 weeks of appropriate therapy are recommended. A number of other diseases caused by viruses, fungi, bacteria and parasites are less common; these include progressive multifocal leukoencephalopathy, herpes simplex and zoster infections and tuberculosis.

AIDS-Related Opportunistic Infections↗
PubMed1992

Other neurological diseases in HIV-1 infection: clinical aspects.

HIV-1-related neurological diseases, excluding opportunistic infections and HIV encephalitis, are considered here. Most occur in severely immunosuppressed patients, with CD4 counts of under 200 x 10(6) l-1. Primary brain lymphoma and metastases from systemic non-Hodgkin's lymphoma, the second commonest cause of cerebral mass lesions in AIDS, are usually aggressive B cell tumours. Their poor median survival after treatment, compared with that of lymphomas in non-AIDS patients, seems related to systemic complications, particularly opportunistic infections. Kaposi's sarcoma produces neurological symptoms exceptionally. Cerebral infarction is often unrecognized clinically but large vessel arteritic occlusions may occur. Intracranial haemorrhages occur mostly in thrombocytopenic patients. Seizures are frequently referred to the neurologist; investigation may lead to a diagnosis of AIDS. Nearly 50% of patients with seizures have cerebral toxoplasmosis or cryptococcal meningitis; HIV-1 encephalitis is presumed to be the cause in 30%. A subacute or chronic vacuolar myelopathy with pyramidal and posterior column signs is the commonest form of spinal cord involvement in AIDS; its cause remains unknown. Peripheral nerve syndromes occur at all stages of HIV-1 infection. Distal symmetrical peripheral neuropathies are the most frequent, particularly a painful form with axonal atrophy, associated with CMV infection, and seen during ARC or AIDS. Mononeuritis multiplex due to vasculitis, CMV, or lymphoma and a serious lumbosacral polyradiculopathy due to CMV are infrequent. The commonest myopathy is due to zidovudine (AZT); it usually responds to drug withdrawal. The nature, prognosis and optimal management of most other myopathies is yet to be determined.

AIDS Dementia Complex↗
PubMed1991

Preferential generation of recurrent responses by groups of motor neurons in man. Conventional and single unit F wave studies.

Conventionally recorded surface F waves over the abductor digiti minimi muscle sampled a wide range of conduction velocities (CVs). Single motor unit (MU) F responses to threshold stimulation of the ulnar nerve were recorded with bipolar needle electrodes (BNE); the mean latencies of their fastest associated surface single unit M and F potentials were similar to those of the compound muscle action potential and fastest F wave, indicating that the fastest F wave indexes adequately the fastest motor fibre of the ulnar nerve. The mean surface unit F amplitude of MUs recorded by a BNE was similar to that of voluntary MUs recorded with a spike-triggered averaging technique; an estimated mean of 2-3 MUs per F wave was found by two methods. The frequency distribution of estimated F wave CVs was shifted towards faster values than expected from available studies of the distribution of CVs in single peripheral nerves; it was also higher than predicted from the expected relation between this distribution and the number of MUs per F wave, if an equal chance of activation and recording is assumed for each MU. There was a significant positive correlation between the frequency of F responses and their CV in 81 single MUs recorded by a BNE and tested with 200 threshold stimuli. These findings are consistent with preferential generation of recurrent responses by larger MUs; it may relate to a lesser chance of antidromic discharge in the smaller motor neurons and to a greater chance of collision of orthodromic (reflex) and antidromic impulses in their axons. The higher than expected percentage of all F waves that were repeater shapes or waves, and the presence of several distinct peaks in the distribution of intervals between repeaters of the same shape, suggest special, and heterogeneous, functional and anatomical arrangements in the groups of motor neurons generating them. Repeaters had greater amplitude and area, but similar latency and duration, than F wave shapes that did not repeat, suggesting that the former have a larger number of component MUs.

Adult↗
PubMed1991

Irish (Donegal) amyloidosis is associated with the transthyretinALA60 (Appalachian) variant.

A cluster of cases of late onset amyloidosis, presenting chiefly with peripheral neuropathy and cardiac failure, has been described in Donegal, north-west Ireland. Molecular genetic and protein analyses show that two new patients from the same region have a mutation in the transthyretin gene previously reported in a family with an Irish ancestor from the Appalachian region of the United States.

Aged↗
PubMed1991

Subclinical peripheral nerve involvement in AIDS: an electrophysiological and pathological study.

Thirty patients with AIDS without symptoms or signs of peripheral neuropathy were compared electrophysiologically with 23 age and sex matched healthy controls. The patients had a mean reduction in the amplitude of common peroneal compound muscle action potentials of 37% (95% CI 11-70%) and of sural sensory action potentials of 34% (CI 18-49%). Mean conduction velocity of both motor and sensory nerves was reduced by between 1 and 7 m/s, with a prolongation of F waves corrected for height of 5% in the arms and 13% in the legs. The distal motor latencies were unchanged. These changes did not correlate with the duration of AIDS, degree of immunosuppression (CD4 count), Body Mass Index, albumin or vitamin B12 level. Four patients had subclinical mononeuropathies. Sural nerve taken at necropsy from five asymptomatic AIDS patients had evidence of axonal degeneration without inflammation or demyelination. There was a mean reduction in myelinated fibre density of 30.5% (CI 10-51%) compared with eight age matched sudden death controls (p = 0.01). This loss principally affected the larger fibres. The pathological and electrophysiological changes indicate axonal degeneration and are similar to those seen in other chronic disorders and in normal ageing. It is concluded that this axonal degeneration is not specific to HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Axonal atrophy in the painful peripheral neuropathy in AIDS.

We compared the sural nerves from patients with AIDS; four with the painful peripheral neuropathy (PPN), three patients with non-painful distal symmetrical peripheral neuropathy (DSPN), one without clinical peripheral nerve involvement and two human immunodeficiency virus negative controls. Fibre diameter distributions showed a slight reduction in larger fibres in all patients with AIDS compared with controls. No significant difference was found in the relative frequency distribution of the lamellae counts between any of the groups. The relative frequency distribution of axonal area of myelinated fibres did not differ between controls, non-painful DSPN or the patient without peripheral nerve involvement; however, all patients with PPN showed marked reduction in the number of axons of myelinated fibres of larger area which was significant when compared to each patient from the other groups (P less than 0.0001). This indicates that the reduction in larger fibres in PPN is mostly due to axonal atrophy rather than selective fibre loss. Axonal atrophy is associated with painful peripheral neuropathy in AIDS but not with those without pain. The possible role of axonal atrophy as a pathological substrate for pain is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Propranolol in acute migraine: a controlled study.

Propranolol is an established agent in migraine prophylaxis. Uncontrolled studies have suggested an action in the acute attack. We present the first double-blind placebo controlled study of propranolol in 27 unselected patients with common (migraine without aura) and classical (migraine with aura) migraine. There were 23 pairs of headaches in the 14 patients who completed the study. No difference was found, when the data were analysed by headache pair or by patient, in severity duration and subjective assessment of efficacy between those treated in an attack with propranolol 40 mg and placebo.

Acute Disease↗
PubMed1990

Migrainous limb pain. A historical note.

Upper and lower limb pain associated to attacks of migraine or cluster headache has been mentioned by many authors since the early descriptions of Liveing, Gowers and Jeliffe. The symptom was also described by Sluder as part of the syndrome of "sphenopalatine ganglion neuralgia." Several authors in the 1920's and 1930's including Cushing and Harris reported cases currently classifiable as migraine or cluster headache with limb pain, but did not accept the mechanisms for pain proposed by Sluder. The scarcity of more recent reports suggests that many patients with migrainous limb pain may be assumed to have other causes for this pain.

Cluster Headache↗
PubMed1990

Comparative efficacy and safety of intravenous and oral administration of a TRH analogue (RX77368) in motor neuron disease.

Ten consecutive patients with motor neuron disease (MND) who had bulbar symptoms received one or two intravenous doses followed by increasing oral doses of a TRH analogue (RX77368). Similar improvements in speech, swallowing and in tongue and jaw movements were seen after iv and oral administration in nine, five and eight patients respectively. The initial time course of improvement correlated with increasing plasma levels of the drug, but most clinical effects persisted when the levels decreased and became undetectable after 24 hours. The oral solution was tasteless and had no, or minimal, side effects.

Administration, Oral↗
PubMed1989

Association of painful peripheral neuropathy in AIDS with cytomegalovirus infection.

12 AIDS patients with a clinically, electrophysiologically, and pathologically homogeneous painful peripheral neuropathy had a significantly higher rate of any or active clinical cytomegalovirus (CMV) infection than did a group of 30 AIDS controls. In 9 patients this syndrome began in close temporal association with clinical infection with CMV. Painful peripheral neuropathy in AIDS may be caused by a CMV dorsal root ganglionitis.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Use of TRH analogues in motorneurone disease.

TRH analogues have a longer half-life than does TRH and enhanced neuropharmacological actions. In motorneurone disease (MND), no benefit was reported with MK771 and DN1417. Focal, transient, and slight improvements in weakness and spasticity were described with CG3509. A controlled trial with a single intravenous dose of RX 77368 showed improvements in dysarthria, tongue movements, respiration, swallowing, and spasticity lasting up to 72 hours. Changes in muscle force were of no functional significance. There was an acute 25-30% increase in mean corrected fiber density and in mean macro-EMG parameters in biceps, but no change in amplitude or area of single macro-EMG motor units followed during the 2-hour infusions. An acute, direct or indirect, central effect of RX77368 on recruitment order or on activation threshold of pathological motor units is suggested. In a subacute open trial with repeated intravenous infusions of RX77368 (median 2 weeks), improvement in bulbar function in 8 of 12 responders, cramps (5 of 9), and spasticity (5 of 8) were maintained for medians of 18, 14, and 7 days, respectively. Side effects were prominent with doses above 0.2 mg/kg. Disease progression has not been halted with any analogue, but whether it may be usefully slowed down with RX77368 is worth investigating.

Amyotrophic Lateral Sclerosis↗
PubMed1989

Combined HIV-CMV encephalitis presenting with brainstem signs.

Two cases of combined HIV-CMV encephalitis are described. One presented with a sixth nerve palsy and a tetraparesis, the other with an internuclear ophthalmoplegia. Pathologically brain stem involvement was predominantly due to CMV.

Acquired Immunodeficiency Syndrome↗
PubMed1989

AIDS: neurological opportunist infections in central London.

Twenty six (41%) of 64 central London cases of AIDS with nervous system involvement during the course of the illness had neurological opportunist infection. Cytomegalovirus and Toxoplasma gondii were the commonest agents in 22 cases with central nervous system (CNS) infection. Eight cases had herpes zoster radiculopathy. Other infections included those caused by Cryptococcus neoformans, Mycobacterium tuberculosis and papova JC virus. Prognosis was generally poor, irrespective of whether the opportunist infection was treatable.

Acquired Immunodeficiency Syndrome↗