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S J Wallace

Publications and source records attributed to S J Wallace.

At least 19 recordsLinked to original sources
PubMed2001

Newer antiepileptic drugs: advantages and disadvantages.

The choice of an antiepileptic drug depends firstly on its efficacy in specific seizure types and epilepsies. However, it is imperative to consider whether possible adverse events will outweigh any benefits. The advantages and disadvantages of vigabatrin, lamotrigine, gabapentin, topiramate, tiagabine and felbamate are considered in some detail, and oxcarbazepine, stiripentol, remacemide, zonisamide and levetiracetam more briefly. Vigabatrin is effective for partial seizures and infantile spasms, but visual field defects are limiting its use. Lamotrigine has a wide spectrum, needs to be prescribed with care. Gabapentin is unlikely to cause adverse effects, but has relatively poor efficacy. Topiramate is widely effective, but can be poorly tolerated. Tiagabine is relatively untried in childhood epilepsies. The use of felbamate is restricted to severe refractory epilepsies. Stiripentol can be effective in severe myoclonic epilepsy in infancy. Zonisamide has a special place in the progressive myoclonus epilepsies. Levetiracetam, remacemide and oxcarbazepine have been used mainly for partial seizures: further studies of their roles in other circumstances are required.

Adolescent↗
PubMed2001

Vigabatrin.

Explore the source record for details and available documents.

Adverse Drug Reaction Reporting Systems↗
PubMed2001

Influence of supplementary fibrolytic enzymes on the fermentation of corn and grass silages by mixed ruminal microorganisms in vitro.

This study was done to determine the effectiveness of supplementary enzymes at increasing the fiber digestion by ruminal microorganisms and to assess whether enzyme activity limits the rate of fiber digestion in ruminal digesta. In vitro comparisons of enzyme activities in two feed enzyme preparations (A and B) with enzyme activities extracted from ruminal fluid indicated that the addition of fibrolytic enzymes at the application rates recommended by the manufacturers would not be expected to increase significantly glycanase and polysaccharidase activities in ruminal fluid. Preparations A and B both increased (P < 0.001) the rate of gas production from freeze-dried corn and grass silages in in vitro incubations with ruminal fluid, but only at concentrations much higher than recommended application rates. Autoclaved controls had little or no effect. Ultrafiltration of enzyme B indicated that most stimulation was due to components >100 kDa, which is consistent with the cause of the stimulation being enzyme activity. Fibrolytic enzymes from other sources were also able to stimulate gas production: increased rates of gas production were observed in seven out of eight combinations of "cellulase" and corn or grass silage (P < 0.05). The comparison of glycanase and polysaccharidase activities with gas-stimulatory activity in the different enzyme preparations indicated that the highest correlation was between increased gas production and enzyme activity against microgranular cellulose (P < 0.05). In a wider range of fibrolytic enzyme preparations, those with endo-(beta-1,4)- or exo-(beta-1,4)-xylanase activity equal to that of preparation A did not produce similar increased rates of fermentation of corn silage when glucanase activity was low (P > 0.05). In contrast, preparations with glucanase activity similar to enzyme A gave at least as great (P < 0.05) an improvement in gas production than enzyme A, irrespective of xylanase activity. It was concluded that enzyme activity, probably a type of endo-(beta-1,4)-glucanase activity, limits the rate of fermentation of corn and grass silage in the rumen. Enzyme supplements of the type used in these experiments are unlikely to possess sufficient activity to overcome this limitation by direct application to ruminal digesta, implying that treatment of the ration prefeeding will be key to harnessing the potential of exogenous fibrolytic enzymes in ruminant nutrition.

Animal Feed↗
PubMed2000

Proteolytic activity of ruminal digesta during the feeding cycle in sheep receiving grass hay/concentrate or maize silage/concentrate diets.

Proteolytic activity was measured by the digestion of 14C-labelled casein in digesta removed from the rumen of four sheep receiving a grass hay/concentrate diet and four sheep receiving a maize silage/concentrate diet. Samples were removed immediately before feeding and at 2-h intervals after feeding up to 12 h. Animals on both diets produced similar proteolytic activities (1.83 (S.D. 0.41) and 2.14 (S.D. 0.61) mg 14C-casein hydrolysed (ml ruminal fluid)-1 h-1 with the maize silage- and grass hay-based diets, respectively). Time after feeding had no effect on proteolytic activity, but between-animal variation was consistent and highly significant, with the highest-activity animals having activities 64 and 74% higher than the lowest-activity animals on the two diets, respectively.

Animal Feed↗
PubMed1998

Myoclonus and epilepsy in childhood: a review of treatment with valproate, ethosuximide, lamotrigine and zonisamide.

Based on small numbers of patients, it is possible to make the following suggestions rather than categorical statements. For myoclonic seizures and epilepsies which are not otherwise specified, valproate seems of proven efficacy. Ethosuximide may be a useful adjunct. The exact place of lamotrigine, which controls some myoclonia and makes them worse in other patients, requires further study. The findings are clearer when specific syndromes are considered. Valproate is the treatment of first choice for benign myoclonic epilepsy in infants, myoclonic astatic epilepsy, epilepsy with myoclonic absences, eyelid myoclonia with absences, juvenile myoclonic epilepsy and progressive myoclonus epilepsy. The addition of ethosuximide to valproate can be helpful to those with myoclonic absences, where this combination appears more beneficial than either valproate or ethosuximide alone and in eyelid myoclonia with absences. Lamotrigine can be effective therapy for juvenile myoclonic epilepsy and eyelid myoclonia with absences when used alone and, in conjunction with other antiepileptic drugs (AED) (usually valproate) for early myoclonic encephalopathy, myoclonic-astatic epilepsy and particularly, epilepsy with myoclonic absences. The myoclonia of infantile neuronal ceroid lipofuscinosis respond to lamotrigine. Severe myoclonic epilepsy of infants usually worsens with lamotrigine, but occasionally, children improve. Zonisamide added to clonazepam and valproate or a barbiturate, can reduce the cascade of myoclonia in progressive myoclonus epilepsies for at least 2 years, but relapse may occur thereafter.

Anticonvulsants↗
PubMed1998

Epilepsy--a guide to medical treatment. 1: Antiepileptic drugs.

The epilepsies are the commonest of serious disorders of brain function. Medical, psychological, social and financial implications can adversely affect quality of life in both patient and family. Accurate categorization of seizure type and epilepsy syndrome, with appropriate choice of drug and other management, can minimize the burden of a seizure disorder.

Adult↗
PubMed1998

Epilepsy--a guide to medical treatment. 2: Non-drug aspects.

Approximately 30-40% of people with epilepsy continue to have seizures despite drug treatment. Factors related to cognitive abilities, physical handicap, psychiatric illness and social circumstances are of great importance in the overall management.

Adolescent↗
PubMed1997

A survey of lamotrigine and vigabatrin treatment in children with severe epilepsy.

A retrospective survey was carried out of add-on treatment with lamotrigine (LTG) and vigabatrin (GVG) in 109 children with severe epilepsy, treated between 1987 and 1994, identified from a total population of 300 patients seen annually, in a tertiary referral outpatient clinic in Cardiff, Wales. Of 79 patient treatments with LTG and 86 with GVG, 42 patients were treated with add-on LTG, 52 with add-on GVG and 20 with both drugs simultaneously. A Kaplan-Meier curve, applied to each of the two index drugs, indicated that 71 and 62% of patients would be expected to continue taking LTG or GVG, respectively after 40 months. Improved seizure control (> or = 50%) at the time of audit was seen in 65% of LTG and 58% of GVG patient treatments for all epilepsy syndromes, but there was a higher proportion of patients with generalized epilepsy improved by LTG (28/41, 68%) than that improved by GVG (8/20, 40%), and only those with generalized epilepsy treated with LTG became seizure free (8/38, 21%). Similar proportions of patients discontinued LTG (16%) and GVG (15%) due to an adverse experience, but a higher proportion discontinued GVG (18%) compared with LTG (6%) because of lack of efficacy. This study supports the relative clinical effectiveness of LTG and GVG in the real world, where children with severe epilepsy are treated in clinical practice and serves to generate hypotheses to enable design of prospectively controlled trials, which should enable more rational use of these two drugs in the paediatric population with epilepsy.

Adolescent↗
PubMed1996

A comparative review of the adverse effects of anticonvulsants in children with epilepsy.

Phenobarbital (phenobarbitone) and phenytoin are the most useful anticonvulsants in neonates because adverse effects are most readily reversed when these drugs are used. Most anticonvulsants are very rarely associated with haematological adverse effects. Platelet function is particularly vulnerable to valproic acid (sodium valproate) therapy. Barbiturates and phenytoin can precipitate metabolic bone disease. Although very infrequent, lymphadenopathy is most common with phenytoin, and lupus-like illnesses with ethosuximide. Valproic acid may precipitate underlying metabolic disorders. Nephrolithiasis can occur with topiramate. Liver disease is most likely with felbamate or valproic acid, but can occur with other anticonvulsants. Valproic acid and ethosuximide are the main precipitants of gastrointestinal symptomatology; while valproic acid and vigabatrin are frequently associated with excessive bodyweight gain. Rash is most likely to occur with barbiturates, but there is a high risk of this adverse effect if large doses of lamotrigine are given with valproic acid. Adverse cosmetic effects are most likely with phenytoin, but valproic acid may cause alopecia. All anticonvulsants may cause unwanted neurological effects: when they occur, diplopia is usually precipitated by carbamazepine; tremor by valproic acid; and other motor disturbances are probably most common with phenytoin. Most anticonvulsants can cause drowsiness. Phenobarbital leads anticonvulsants as a cause of behavioural difficulties. Effects of anticonvulsants on cognitive function are difficult to assess, but subtle changes have been reported for all anticonvulsants in use up to the 1980s. Compared with other anticonvulsant drugs, phenytoin and felbamate are more often discontinued as a result of unwanted effects.

Adolescent↗
PubMed1995

Lamotrigine for the treatment of epilepsy in childhood.

OBJECTIVE: In this multicenter study, the efficacy and tolerability of lamotrigine were assessed in 285 children less than 13 years of age, recruited from 37 centers in 11 countries. METHODS: Pooled data from five open add-on studies have been analyzed. All the children had treatment-resistant epilepsy and most had two or more seizure types. Seizure frequency and global evaluation were assessed at the end of four successive 12-week periods of therapy. RESULTS: Seizure frequency was reduced by 50% or more in one third of the patients. Lamotrigine was effective in all seizure types examined, particularly for typical and atypical absence seizures. Atonic seizures also responded well. Improvement was well maintained during the treatment period. The maintenance dose had to be adjusted according to concomitant medication; dose ranges were 1 to 5 mg/kg per day for children taking valproate and 5 to 15 mg/kg per day for those not taking valproate. The commonest reported adverse experiences were somnolence, rash, vomiting, and seizure exacerbations. Adverse experiences led to withdrawal of treatment from 36 patients (12.6%). CONCLUSIONS: These results indicate that lamotrigine is well tolerated and is effective for a broad range of seizure types, especially absence seizures and atonic seizures.

Adolescent↗
PubMed1995

Management issues in severe childhood epilepsies.

The severe epilepsies of childhood are described briefly and information available on the efficacy of newly developed antiepileptic drugs (AEDs) in their control is reviewed. Therapeutic advances are awaited for early infantile epileptic encephalopathy, early myoclonic encephalopathy, progressive myoclonus epilepsies and Kojewnikow syndrome. West syndrome may respond to vigabatrin, and less predictably to lamotrigine. Lamotrigine can be helpful for severe myoclonic epilepsy and myoclonic absences. Astatic seizures may be dramatically controlled by lamotrigine, whereas vigabatrin may worsen myoclonic attacks. In the Lennox-Gastaut syndrome, the efficacy of felbamate has been demonstrated by a controlled trial; vigabatrin and lamotrigine can also be helpful. Non-idiopathic partial and secondary generalized epilepsies are responsive to vigabatrin in a useful percentage of cases, and some children improve with felbamate, lamotrigine or striripentol. A trial which compares the efficacies of the newer AEDs against each other could provide very useful information for the clinician.

Adolescent↗
PubMed1995

Convulsive status epilepticus in children treated for epilepsy: an assessment of management.

The acute care and further management plans accorded to eight children, all already on treatment for epilepsy, admitted to hospital with a total of 17 episodes of convulsive status epilepticus were examined. Emergency treatment was appropriate, but longer-term management tended to be less than adequate. The causes of status epilepticus were not considered before discharge on 10 occasions. Advice on simple preventative measures was rarely given to the parents. Junior staff require further training in these areas.

Administration, Rectal↗
PubMed1995

Intracranial tumours during the first two years of life: presenting features.

Between 1979 and 1994, 21 children (nine females, 12 males) with intracranial tumours diagnosed before the age of 2 years (range 2-23 months) were treated at the University Hospital of Wales. The commonest presenting symptoms were vomiting (n = 9) and unsteadiness (n = 8); the commonest presenting sign was enlarged occipitofrontal circumference (> 97th centile in 16 and > 90th centile in a further two). In five cases with signs of raised intracranial pressure, meningitis was the clinical diagnosis, and a lumbar puncture was performed. For cases with long delays in diagnosis, multiple other disorders had been considered and the significance of head enlargement had not been recognised. In very early childhood, intracranial tumours are uncommon and can mimic other disorders, especially meningitis. Early neuroimaging is advised when a child presents with recent onset of neurological symptoms and a disproportionately large head.

Astrocytoma↗
PubMed1994

Practical problems of epilepsy management in children.

The problems associated with the investigation, diagnosis and treatment of epilepsy in children are considered in this paper, together with aspects of intellectual development. In addition, the difficulties encountered in family and school environments are reviewed. The problems which arise when medication is discontinued, and the possible importance of the loss, as well as the acquisition, of a condition, are also discussed.

Anticonvulsants↗