Proteomics-based anticancer drug discovery and development

Proteins are important targets for drug discovery and this applied to cancer as well because there is a defect in the protein machinery of the cell in malignancy. Proteomic technologies are now being integrated with genomic approaches for cancer drug discovery and target validation. Among the large number of proteomic technologies available for this purpose, the most important ones are 3-D protein structure determination, protein microarrays, laser capture microdissection and study of protein-protein and protein-drug interactions. Cancer biomarkers and several cell pathways are important drug targets. Several companies are involved in using proteomic technologies for drug discovery. Finally, proteomic approaches will play an important role in the discovery and development of personalized medicines.

Oncoproteomics: state-of-the-art

Proteomics is a promising approach in the identification of proteins and biochemical pathways involved in carcinogenesis. Proteomic technologies are now being incorporated in oncology in the post-genomic era. Cancer involves alterations in protein expression and provides a good model not only for detection of biomarkers but also their use in drug discovery. Proteomics has an impact on diagnostics as well as drug discovery. Genomics still remains an important approach but the value of proteomics lies in the fact that most of the diagnostics and drugs target proteins. The importance of application of proteomics in oncology is recognized by the publication of this special issue of TRCT.

Role of proteomics in diagnosis of cancer

Proteomic technologies have emerged as an important addition to the genomic and antibody-based technologies for the diagnosis of cancer. Important technologies include 2-D gel electrophoresis, mass spectrometry, laser capture microdissection, detection of molecular markers of cancer and protein patterns. For clinical applications, the most likely technologies to be used widely are protein biochips. Application of these technologies to various cancers are described. Proteomic technologies have a potential in developing molecular diagnostics and markers for the early detection of cancer. However, information from various diagnostic technologies should be integrated to obtain the optimal information required for clinical management of a patient.

Applied neurogenomics

Neurogenomics, the study of the genes of the nervous system, has applications in basic research, in the pharmaceutical industry and in the management of neurological disorders. Basic research applications include molecular neuropathology, the detection of genes for neurological disorders, the study of gene expression in the CNS and creation of transgenic models of neurological disorders. Pharmaceutical applications may be in the areas of molecular neuropharmacology, the discovery of new drugs for neurological disorders, gene therapy and the development of personalised medicines based on pharmacogenomics. Clinical applications in neurology include the redefinition and reclassification of diseases, molecular diagnostics and the integration of diagnostics with therapeutics. Various methods for the study of genes and gene expression are described. Genes have been identified for only a limited number of neurological disorders so far. The discovery of genes defective in neurological disorders would facilitate drug discovery, molecular diagnostics and gene therapy diseases. There is a trend towards the integration of diagnosis, genetic screening, prevention, treatment and monitoring of therapy of neurological disorders, which will be facilitated by neurogenomics. Pharmacogenomics-based personalised medicines are anticipated to be part of medical practice by the end of the first decade of the 21st century, and neurogenomics will contribute to the development of personalised medicines for diseases of the CNS.

Use of bacteria as anticancer agents

Historically, bacteria were used as oncolytic agents for malignant brain tumours. Advances in bacteriology and molecular biology have widened the scope of bacterial approaches to cancer therapy and various possibilities include the use of bacteria as sensitising agents for chemotherapy, as delivery agents for anticancer drugs, and as vectors for gene therapy. Bacterial toxins can be used for tumour destruction and cancer vaccines can be based on immunotoxins of bacterial origin. The most promising approaches are the use of genetically modified bacteria for selective destruction of tumours, and bacterial gene-directed enzyme prodrug therapy. Knowledge gained from study of bacterial genomes forms an important basis of use of bacteria as anticancer agents. TAPET (Tumour Amplified Protein Expression Therapy) uses a genetically altered strain of Salmonella as a bacterial vector, or vehicle, for preferentially delivering anticancer drugs to solid tumours. Verotoxin 1 (VT1) of Escherichia coli has been used for ex vivo purging of human bone marrow of cancer cells before autologous bone marrow transplant. E. coli genes and enzymes have become part of well-known prodrug approaches to cancer in which inert prodrugs can be converted in vivo to highly active species. IL-4 fused with Pseudomonas exotoxin has been administered directly into malignant brain tumours and binds with high affinity to IL-4 receptors, which do not exist on normal brain cells, thus destroying a major part of the tumour without harming the normal brain tissue. It is in Phase I/II clinical trials in patients with glioblastoma. No ideal anticancer agent of bacterial origin that is applicable to all types of cancers has been discovered yet. The most promising approach to malignant brain tumours appears to be the use of genetically engineered bacteria that destroy the tumour selectively while sparing the normal brain tissue.

Cambridge Healthtech Institute's Third Annual Conference on Lab-on-a-Chip and Microarrays. 22-24 January 2001, Zurich, Switzerland

Cambridge Healthtech Institute's Third Annual Conference on Lab-on-a-Chip and Microarray technology covered the latest advances in this technology and applications in life sciences. Highlights of the meetings are reported briefly with emphasis on applications in genomics, drug discovery and molecular diagnostics. There was an emphasis on microfluidics because of the wide applications in laboratory and drug discovery. The lab-on-a-chip provides the facilities of a complete laboratory in a hand-held miniature device. Several microarray systems have been used for hybridisation and detection techniques. Oligonucleotide scanning arrays provide a versatile tool for the analysis of nucleic acid interactions and provide a platform for improving the array-based methods for investigation of antisense therapeutics. A method for analysing combinatorial DNA arrays using oligonucleotide-modified gold nanoparticle probes and a conventional scanner has considerable potential in molecular diagnostics. Various applications of microarray technology for high-throughput screening in drug discovery and single nucleotide polymorphisms (SNP) analysis were discussed. Protein chips have important applications in proteomics. With the considerable amount of data generated by the different technologies using microarrays, it is obvious that the reading of the information and its interpretation and management through the use of bioinformatics is essential. Various techniques for data analysis were presented. Biochip and microarray technology has an essential role to play in the evolving trends in healthcare, which integrate diagnosis with prevention/treatment and emphasise personalised medicines.

An assessment of iloperidone for the treatment of schizophrenia

Iloperidone (Novartis' Zomariltrade mark) is an atypical antipsychotic agent for the treatment of schizophrenia. Current trends in the treatment of schizophrenia indicate that some atypical antipsychotics are being recommended as first-line therapy. Atypical antipsychotics, in addition to being dopamine (D) receptor antagonists, are all relatively potent serotonin (5-HT) receptor antagonists and are less likely than conventional dopamine antagonists to induce movement disorders. However, all of these agents differ in their receptor profiles and clinical profiles. Iloperidone, a benzisoxazole, is a mixed 5-HT(2A)/D(2)antagonist. Iloperidone was found to be more potent than its analogues when compared with haloperidol in antagonising climbing behaviour in mice. Iloperidone is extensively metabolised and the main circulating metabolite is reduced iloperidone. In patients treated with iloperidone, a low incidence of extrapyramidal symptoms and weight gain has been shown. Data from Phase II trials demonstrated efficacy in patients at doses of 8 mg/day and tolerability was good up to 32 mg/day. Phase III prospective, double-blind, randomised trials with iloperidone are in progress under the ZEUS (Zomariltrade mark Efficacy Utility and Safety) programme involving 3300 patients. Iloperidone, with a balance of activity at the dopaminergic and serotonergic receptors, has obvious advantages over clozapine and olanzapine, both of which have a similar receptor profile as they favour serotonergic over dopamine receptors. Iloperidone is likely to reach the market in 2001 and has favourable prospects in the atypical antipsychotic market for schizophrenia, which is expanding from US$ 1.5 billion in 2000 to US$ 3 billion in 2005.

Evaluation of intravenous parecoxib for the relief of acute post-surgical pain

Parecoxib is a prodrug of valdecoxib, which is a potent and selective inhibitor of COX-2. Intravenous preparation of parecoxib is in Phase III clinical trials for the management of acute and severe post-surgical pain. It is the only COX-2 inhibitor that is available in a parenteral formulation. Clinical results compare parecoxib with ketorolac, a NSAID, which is the only non-narcotic analgesic available in parenteral formulation that can be administered for the relief of moderate to severe acute pain. Pharmacokinetic studies have shown that parecoxib is converted to valdecoxib within a short time following administration by im. or iv. injection. In clinical trials, parecoxib compares favourably with ketorolac and produces less gastric or duodenal ulcers, the predominant adverse effect, than ketorolac. Parecoxib, thus, fulfils some of the desirable characteristics of an ideal non-narcotic analgesic for severe post-surgical pain and has application in other acutely painful conditions. Parecoxib is expected to be filed for approval before the end of 2000 and is expected to be introduced in the market in 2001. It has favourable prospects for a fair share of the post-surgical pain relief market which is valued at approximately US$ 1 billion for the year 2000.

Applications of proteomics in oncology

Genomics has expanded the field of molecular oncology, and proteomics is complementing genomics in the fields of elucidation of pathophysiology, gene function, molecular diagnosis and anticancer drug discovery. This trend is reflected in the establishment of the Human Tumour Gene Index by the National Cancer Institute (NCI), which is now followed by the Tissue Proteomics Initiative. Laser capture microdissection (LCM) provides an ideal method for extraction of cells from specimens in which the exact morphologies of both the captured cells and the surrounding tissue are preserved. Proteomic technologies can be applied for the further characterisation and analysis of proteins. LCM can also be combined with the protein chip technology. Proteomic technologies have been used for the study of cancer of various organs including the liver, prostate, breast, bladder and oesophagus. Some of the anticancer strategies are directed against proteases that facilitate several steps in cancer progression. Proteomic mapping of blood vessels in normal and malignant tissues can be used to identify tissue-specific markers on the endothelium that serve as potential targets for in vivo drug delivery. Studies of global protein expression in human tumours have led to the identification of various polypeptide markers, potentially useful as diagnostic tools. Genes that encode proteins that are overexpressed in tumours are being identified. Demonstration of tissue or cell type specific expression of some nuclear matrix proteins has led to the search for tumour specific nuclear matrix proteins. There is considerable activity in the commercial sector to develop diagnostic tests, as well as to facilitate anticancer drug discovery using proteomic technologies. Continued refinement of techniques and methodologies to determine the abundance and status of proteins in vivo holds great promise for future study of normal cells and associated neoplasms.

An evaluation of intrathecal ziconotide for the treatment of chronic pain

Ziconotide, the synthetic form of cone snail peptide pi-conotoxin MVIIA, is a neurone-specific N-type calcium channel blocker with an analgesic and neuroprotective effect. Intrathecal ziconotide has been recommended for approval by the FDA for the management of chronic pain. Spinally administered ziconotide produces analgesia by blocking neurotransmitter release from primary nociceptive afferents and prevents the propagation of pain signals to the brain. It has an advantage over intrathecal morphine in that there is no development of tolerance after prolonged use. Systemic toxicity is considerably reduced by administration of smaller doses intrathecally and selective delivery to the site of action in the nervous system. Nevertheless, there are neurological adverse effects due to delay in clearance of ziconotide from the neural tissues. Overall, ziconotide has a favourable risk/benefit ratio with advantages over several currently available intrathecal therapies for pain.

An assessment of zonisamide as an anti-epileptic drug

A brief review of epilepsy as a disease, anti-epileptic drugs and methods of evaluation of anti-epileptic drugs are presented as a background for assessment of zonisamide, which has been approved by the FDA as add-on therapy for the treatment of partial seizures with or without secondary generalisation in adults. Chemically, zonisamide is classified as a sulphonamide and is unrelated to other anti-epileptic drugs. The mode of action of zonisamide remains unclear, but likely mechanisms are blockade of sodium and T-type calcium channels. It is also shown to have some neuroprotective effect against hypoxia and ischaemia. It has a liner pharmacokinetics with excellent oral bioavailability. Zonisamide has been approved for use in Japan for ten years prior to approval in USA and Europe. Clinical experience with zonisamide in Japan has documented its efficacy in the treatment of partial seizures (partial-onset generalised tonic-clonic, simple partial and/or complex partial seizures) and to a more variable extent, generalised tonic-clonic, generalised tonic (mainly seen in symptomatic generalised epilepsies including Lennox-Gastaut Syndrome) and compound/combination seizures. The efficacy and safety was confirmed in trials conducted in USA and Europe in adults as well as children. Zonisamide compares favourably with other newly introduced drugs and has the potential for development as a monotherapy for epilepsy.

Applications of biochip and microarray systems in pharmacogenomics

A DNA microarray system is usually comprised of DNA probes formatted on a microscale on a glass surface (chip), plus the instruments needed to handle samples (automated robotics), to read the reporter molecules (scanners) and analyse the data (bioinformatic tools). Biochips are formed by in situ (on chip) synthesis of oligonucleotides or peptide nucleic acids (PNAs) or spotting of DNA fragments. Hybridisation of RNA- or DNA-derived samples on chips allows the monitoring of expression of mRNAs or the occurrence of polymorphisms in genomic DNA. Basic types of DNA chips are the sequencing chip, the expression chip and chips for comparative genomic hybridisation. Advanced technologies used in automated microarray production are photolithography, mechanical microspotting and ink jets. Bioelectronic microchips contain numerous electronically active microelectrodes with specific DNA capture probes linked to the electrodes through molecular wires. Several biosensors have been used in combination with biochips. PNA biosensors commonly rely on the immobilisation of a single-stranded DNA sequence (the 'probe') onto a transducer surface for hybridisation with the complementary ('target') strand to give a suitable electrical signal. Other sensors are cell-based immunobiosensors with engineered molecular recognition, integrated biosensors based on phototransistor integrated circuits and sensors based on surface plasmon resonance. Microarray technologies offer enormous savings in time and labour as compared to standard gel-based microsatellite methods. Reading of the information and its management by bioinformatics is necessary because of the enormous amount of data generated by the various technologies using microarrays. Standardised procedures are essential for compatible data production, quality control and analysis. Expression monitoring is the most biologically informative application of this technology at present. Microarray technology has important applications in pharmacogenomics: drug discovery and development, drug safety and molecular diagnostics. DNA chips will facilitate the integration of diagnosis and therapeutics, as well as the introduction of personalised medicines.

An assessment of levetiracetam as an anti-epileptic drug

A brief review of epilepsy as a disease, anti-epileptic drugs (AEDs) and methods of evaluation of AEDs are presented as a background for the assessment of levetiracetam which has been approved by the FDA as add-on therapy for the treatment of partial seizures with or without secondary generalisation in adults. The exact mechanism of action of levetiracetam is not known but its action differs from that of other anti-epileptic drugs. A specific binding site for levetiracetam has been identified and is possibly related to anticonvulsant activity. Levetiracetam offers an effective and broad spectrum treatment of epileptic seizures, partial as well as generalised epilepsy. Levetiracetam has been shown to be effective in genetic and kindled animal models of epilepsy and against chemoconvulsant-induced partial epileptic seizures. Levetiracetam has a near perfect pharmacokinetic profile, with rapid absorption following oral administration, excellent bioavailability, quick attainment of steady-state concentrations, linear kinetics and minimal plasma protein binding. Levetiracetam does not interact with commonly used drugs and other AEDs. In recent Phase III clinical trials, the responder rate was 39.4 - 42.1% on 3000 mg dose, compared with placebo rates of 10.9 - 16.7%. Levetiracetam has a favourable safety profile and the most frequently reported adverse events were somnolence, asthenia and dizziness. Overall, levetiracetam is considered to have several advantages over current AEDs.

Evaluation of memantine for neuroprotection in dementia

Memantine, a non-competitive NMDA antagonist, has been approved for use in the treatment of dementia in Germany for over ten years. The rationale for use is excitotoxicity as a pathomechanism of neurodegenerative disorders. Memantine acts as a neuroprotective agent against this pathomechanism, which is also implicated in vascular dementia. HIV-1 proteins Tat and gp120 have been implicated in the pathogenesis of dementia associated with HIV infection and the neurotoxicity caused by HIV-1 proteins can be blocked completely by memantine. Memantine has been investigated extensively in animal studies and following this, its efficacy and safety has been established and confirmed by clinical experience in humans. It exhibits none of the undesirable effects associated with competitive NMDA antagonists such as dizocilpine. The efficacy of memantine in a variety of dementias has been shown in clinical trials. Memantine is considered to be a promising neuroprotective drug for the treatment of dementias, particularly Alzheimer's disease for which there is no neuroprotective therapy available currently. It can be combined with acetylcholinesterase inhibitors which are the mainstay of current symptomatic treatment of Alzheimer's disease. Memantine has a therapeutic potential in numerous CNS disorders besides dementias which include stroke, CNS trauma, Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), epilepsy, drug dependence and chronic pain. If memantine is approved by the FDA for some of these indications by the year 2005, it can become a blockbuster drug by crossing the US$1 billion mark in annual sales.

Evaluation of mitoxantrone for the treatment of multiple sclerosis

Mitoxantrone (Novantrone((R))), an antineoplastic agent, has been approved for treating patients with secondary progressive multiple sclerosis (MS). Mitoxantrone, which is usually categorised as an immunosuppressant drug, is now also considered to be a specific immunomodulator. Autoimmune mechanism of pathogenesis of MS is the basis of immunosuppressive therapeutic approaches to MS whereas immunoregulatory abnormalities including defective IFN-alpha production provide the rationale for immunomodulating therapies. Clinical trials have shown that mitoxantrone had a statistically significant impact on reduction of relapse rate and delay in disability progression in these patients. Advantages of mitoxantrone as therapy for MS are: (1) considerable information is available about its pharmacokinetics, metabolism and toxicology from previous use in oncology; (2) it requires administration only once in three months which is not only convenient for the patient but also cost-effective; (3) mitoxantrone is one of the two drugs to be approved for secondary progressive MS (the other is IFN-beta1) which offers an advantage over IFN-beta1a preparations and glatiramer acetate which are indicated only for relapsing remitting MS. However, the duration of therapy is usually limited to two to three years because the maximum cumulative dose recommended is 120 mg/m(2) due to concern for possible cardiotoxicity. Potential market value of the mitoxantrone, based on the cost of treatment per patient and the number of patients likely to be treated in the first year of introduction, is US$210 million.

Nicaraven for the treatment of cerebral vasospasm in subarachnoid haemorrhage

Cerebral vasospasm is a complication of subarachnoid haemorrhage and can cause cerebral ischaemia. Antivasospastic agents are used to relieve vasospasm after subarachnoid haemorrhage. A large number of agents with varying modes of action currently being investigated are reviewed. Pharmacology and clinical trials of nicaraven are discussed. The drug has been found to have both antivasospastic as well as neuroprotective effects. Clinically, the most documented efficacy of nicaraven is in the management of vasospasm associated with subarachnoid haemorrhage based on its free radical scavenging effect. Other potential areas for application are cerebral oedema associated with intracerebral haemorrhage and for neuroprotection in cerebral infarction. Nicaraven is in pre-registration by Chugai Pharma Ltd. in Japan for the treatment of vasospasm following subarachnoid haemorrhage. The regulatory atmosphere in Japan regarding the approval of neuroprotectives is reviewed and nicaraven is likely to be approved by the year 2001 when the patent on it expires.

Neuroprotection in cerebrovascular disease

The role of neuroprotection in the management of acute cerebrovascular disease is reviewed. Neuroprotection is a valuable adjunct to thrombolytic therapy in acute cerebral ischaemia. Various pharmacological approaches for neuroprotection are based on the current knowledge of molecular events in the pathophysiology of cerebral ischaemia. Reperfusion injury following restitution of circulation is also considered to be mediated by free radicals. Various strategies include free radical scavengers, anti-excitotoxic agents, apoptosis (programmed cell death) inhibitors, anti-inflammatory agents, metal ion chelators, ion channel modulatory, antisense oligonucleotides and gene therapy. The various agents aim to prevent the progression of ischaemic cascade therefore reducing brain damage and some of these intervene at more than one point in the ischaemic cascade. Neuroprotection is considered as an adjunct to therapies designed to improve cerebral circulation such as thrombolytic agents for arterial thrombosis. Clinical effectiveness of some of the strategies has not be proven in clinical trials, some of which had to be abandoned due to adverse effects outweighing the beneficial effects. Efforts to develop new neuroprotective agents continue and prospects for the introduction of an effective neuroprotective agent(s) in the next few years are good. Apart from acute cerebrovascular disease, neuroprotective therapy has a role in preventing cerebral ischaemia in high risk cardiovascular procedures as well as in neurodegenerative disorders which has some common pathomechanisms with cerebrovascular disease. Currently, the most promising agents are free radical scavengers. In the near future, gene therapy approaches are likely to prove more effective in neuroprotection.

An assessment of rufinamide as an anti-epileptic in comparison with other drugs in clinical development

This article evaluates rufinamide, a new anti-epileptic drug (AED) in Phase III development. This review is done against the background of therapeutic challenges of epilepsy, old established AEDs, newly introduced AEDs and AEDs in clinical development. Pharmacological properties of 12 AEDs in clinical trials (Phases I - III) are compared: ADCI, AWD 131-138, DP-VPA, ganaxolone, levetiracetam, losigamone, pregabalin, remacemide hydrochloride, retigabine, rufinamide, soretolide and TV1901. One of these, levetiracetam has been approved in the USA and is waiting approval in other countries. The protective index of rufinamide, as shown in rodent models of epilepsy, is much higher than that of most common AEDs. Features which make it a desirable AED are: (i) a broad spectrum of anti-epileptic actions including both partial and symptomatic generalised epilepsy; (ii) a statistically significant reduction in seizure frequency in clinical trials; (iii) efficacy and safety shown in a broad range of age groups including children and the elderly; (iv) rapid oral absorption enabling quick titration to effective dose and (v) a benign adverse event profile. Most of the events did not lead to discontinuation in clinical trials. These features offer considerable advantages over the existing anti-epileptic drugs. It is one of the two drugs in development which have reached Phase III and is expected to be approved by the year 2001 - 2002.

Sweet's syndrome associated with granulocyte colony-stimulating factor

Sweet's syndrome has been reported to occur in patients with malignant and inflammatory diseases. It may occur as an adverse reaction to the use of drugs, particularly the recombinant human granulocyte colony-stimulating factor (Filgrastim).

Cutaneous vasculitis associated with granulocyte colony-stimulating factor

BACKGROUND

Several cases of cutaneous vasculitis have been reported in patients treated with granulocyte colony-stimulating factor (G-CSF).

OBJECTIVE

The purpose of this study was to determine the prevalence of cutaneous vasculitis in patients receiving G-CSF therapy, causal relation to the drug, and possible pathomechanisms.

METHODS

Review of the literature, retrieval of cases from the safety database of the manufacturer of G-CSF, and global assessment of the causal relation of the drug to adverse drug reactions were done.

RESULTS

Eighteen cases of cutaneous vasculitis were found, of which only three have been published. A skin biopsy was done in 12 and showed leukocytoclastic vasculitis. Although cutaneous vasculitis was rare in patients treated for neutropenia associated with malignant disease and chemotherapy, it occurred in 6% of the patients with chronic benign neutropenias. Cutaneous vasculitis usually followed the increase of absolute neutrophil count (ANC) and subsided after the decrease of ANC. There was no recurrence if ANC was kept below 800/mm3. The course of G-CSF was completed in most patients.

CONCLUSION

Cutaneous vasculitis should be recognized as an adverse reaction to G-CSF with low morbidity. It can be managed by reduction of dose or discontinuation of G-CSF therapy and use of topical steroids.

High-pressure neurological syndrome (HPNS)

High-pressure neurological syndrome (HPNS) is a condition encountered in diving beyond a depth of 100 m. Manifestations include headache, tremor, myoclonus, neuropsychiatric disturbances and EEG changes. Convulsions are seen only in experimental animals. Most of the changes are reversible on surfacing but some such as memory disturbances may linger on for long periods. Excessive atmospheric pressure is the most important factor in the pathogenesis of HPNS. Neurotransmitter changes occur of which serotonin appears to be a more likely mediator because of the resemblance of HPNS to serotonin syndrome. Anesthetics and anticonvulsants have been used in experimental animals but are unsuitable for use in human divers. Breathing gas mixtures such as heliox have enabled the extension of depth of diving without HPNS. Use of 5-HT1A receptor antagonists may provide an interesting approach to prevention of HPNS.

Investigation and Management of Loss of Efficacy of an Antiepileptic Medication Using Carbamazepine as an Example

Cases reported as loss of efficacy (secondary failure) of carbamazepine (CBZ) for epilepsy were analysed to determine the cause. In these cases, seizures previously controlled with CBZ, recurred or increased in frequency. The following causes were identified in 131 cases where adequate information was available: use for types of epilepsy where this drug is not recommended, lowering of the blood levels of the drug on switching over from branded to a generic CBZ, change in the galenic form, drug interactions, progression of the underlying brain pathology such as a brain tumor, and unexplained increase in the blood levels of the drug. In cases where the increase in seizures was transient no special measures or changes in therapy were required. Unexplained failure occurred only in seven cases (5.3%). Based on this information, a flow chart was designed to evaluate such a problem step by step and to take appropriate measures. Only when true therapeutic failure is identified, should another antiepileptic drug be substituted for CBZ. Similar approach can be used for other antiepileptic drugs.

Systemic lupus erythematosus (SLE)-like syndromes associated with carbamazepine therapy

Records of 80 cases of systemic lupus erythematosus (SLE)-like syndromes associated with use of carbamazepine entered in the single case files of Central Drug Monitoring, Ciba-Geigy, Basel, were reviewed. Included in these were 11 cases reported in the literature. These were assessed in light of the current concepts of both idiopathic and drug-induced forms of SLE. Even allowing for under-reporting of adverse drug reactions, the number of such cases is far below the prevalence rates for SLE. This adverse drug reaction remains allocated to the category 'isolated cases' i.e. frequency is less than 0.001% of the cases treated. Antinuclear antibody (ANA) and anti-double-stranded DNA (anti-dsDNA) tests were not helpful in differentiating between idiopathic and drug-induced SLE. IgG antihistone antibodies in the absence of high titres of dsDNA antibodies is the only reliable test. Symptoms of SLE-like syndromes which manifest after carbamazepine therapy usually subside after discontinuation of the drug. Persistence of symptoms support the diagnosis of idiopathic SLE.

Incision of the brain with the Varipulse carbon dioxide laser: a preliminary study for potential application in neurosurgery

Incisions were made into the rat brain using the Varipulse carbon dioxide laser; they were compared with those made by using an equal amount of energy in the continuous mode of the same laser. Histological examination of the cross sections of the incisions was done. The Varipulse CO2 laser, in comparison with the continuous wave CO2 laser, caused less damage to the tissues surrounding the incision. A 500 Z (peak power, 500 watts) NIIC carbon dioxide laser (Cooper Laser Sonics, Santa Clara, California) equipped with a microcomputer was used with a pulse repetition rate of 200 to 400 and a pulse width of 0.1 second. A focused spot of 0.2 mm and a constant speed of incision of 5 mm/second was used for both types of lesions. The potential usefulness of the Varipulse CO2 laser in neurosurgery, as well as the precautions to be observed during its use, are discussed.

A prospective randomized comparison of epirubicin and doxorubicin in patients with advanced breast cancer

Fifty-four patients with advanced breast cancer who had failed prior non-anthracycline combination chemotherapy were randomized to treatment with either epirubicin 85 mg/m2 or doxorubicin 60 mg/m2 intravenously every three weeks. Of 52 evaluable patients, 25% (six of 24) treated with epirubicin, and 25% (seven of 28) treated with doxorubicin experienced major therapeutic responses. The median duration of response to epirubicin was 11.9 months compared to 7.1 months with doxorubicin. Cardiotoxicity was monitored by serial multigated radionuclide cineangiocardiography performed at rest and after exercise. Laboratory evidence of cardiotoxicity was defined as a decrease in resting left ventricular ejection fraction of greater than 10% from the baseline value, or a decrease of 5% or greater with exercise compared with the resting study performed on the same day. Fifteen patients treated with epirubicin and 18 patients treated with doxorubicin had at least two determinations of left ventricular ejection fraction and were evaluable for laboratory cardiotoxicity. Using methods of survival analysis, the median doses to the development of laboratory cardiotoxicity were estimated to be 935 mg/m2 of epirubicin and 468 mg/m2 of doxorubicin. Four patients treated with epirubicin and five treated with doxorubicin developed symptomatic congestive heart failure. The median cumulative dose at which congestive heart failure occurred was 1,134 mg/m2 of epirubicin compared with 492 mg/m2 of doxorubicin. Fewer episodes of nausea and vomiting were observed in patients receiving epirubicin. Epirubicin is a new anthracycline with reduced cardiac toxicity, but preserved efficacy in the treatment of patients with advanced breast cancer.

Complications of use of the neodymium: yttrium-aluminum-garnet laser in neurosurgery

Review of the clinical records of 32 patients who underwent operation for brain tumors with the use of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser during a 4-month period revealed 5 cases of complications related to laser use. One death was presumed to be due to intratumor explosion (the popcorn effect) after excessive Nd:YAG laser application. The other death was due to heat necrosis of the brain stem after radiation of an ependymoma of the 4th ventricle. Two patients suffered neurological deficits. One had facial palsy after radiation of the site of attachment of a meningioma to the petrous bone. The other suffered aphasia and hemiparesis due to heat damage to the cerebral cortex after laser coagulation of the overlying dura mater. The fifth patient suffered postoperative hemorrhage in a residual necrotic chromophobe adenoma after a transsphenoidal approach using the Nd:YAG laser. These complications are preventable. Suggestions are made for the safe use of this laser.

The treatment of extragonadal seminoma

Primary extragonadal seminoma (EGS) is a rare tumor of young adults that often presents with bulky primary tumors and metastatic disease. Long-term survival is inadequate with conventional therapy consisting of radiotherapy with or without surgery. The charts of 21 patients with EGS treated initially either with conventional therapy (group I) or with multimodality therapy including initial chemotherapy with high doses of cisplatin followed by either radiotherapy or surgery or both (group II) were reviewed. Five of the ten patients in group I developed recurrent disease and four of them eventually died of disease. Only one of 11 patients in group II died of metastatic disease and the remaining patients are free of disease with 19+ to 46+ months of follow-up. Of the six patients from group II who underwent surgical resection of apparently residual disease after chemotherapy but prior to radiotherapy, five were found to have completely necrotic tumor and one had microscopic disease on histologic examination, proving the efficacy of chemotherapy. Combined modality therapy including initial chemotherapy containing high doses of cisplatin provided rapid reduction in tumor burden and the results appeared superior to treatment that did not include initial chemotherapy.

Cerebral protection during carotid endarterectomy--EEG monitoring as a guide to the use of intraluminal shunts

The authors have reviewed the literature concerning measures for cerebral protection during carotid endarterectomy, with particular reference to the controversy regarding the use of an intraluminar shunt. The authors use preoperative EEG analysis during the carotid compression test as well as intraoperative EEG monitoring, and insert a shunt only when signs of cerebral ischaemia appear. This approach was used in 100 patients during a 4 year period and an internal shunt was required in only 10% of these patients. The mortality was 1% and morbidity 1% in this series. The authors believe that EEG monitoring is a reliable technique in detecting signs of cerebral ischaemia before irreversible changes occur and that an intraoperative shunt should be used only when necessary, and not routinely, as it may contribute to operative and postoperative complications.

[Lasers in neurosurgery]

In recent years neurosurgeons have shown an increasing interest in lasers. An understanding of the basic laser mechanism and tissue effects is important. CO2 laser is an excellent no-touch tool for excising and evaporating brain tumors. It has several other uses in neurosurgery both with free hand technique and with microscope attachment and micromanipulator. Nd: YAG and Argon lasers are more effective for coagulation of blood vessels and dealing with vascular neoplasms. Advantages and disadvantages of this technique are discussed and compared with other methods like bipolar coagulation and CUSA. Indications for the use of the different laser types in neurosurgery are summarized and a prospect of laser in neurosurgery is given.

Pitfalls in diagnosing intracranial aneurysms

A medical record review of 90 consecutive patients with intracranial aneurysm disclosed a startling incidence of delayed or incorrect diagnosis. In 31 of the patients, the diagnosis was not made by the referring physician. Definite diagnosis by angiography will detect an aneurysm as small as 2 mm when there is no spasm of the parent vessel. A high index of suspicion and the use of computed tomography with contrast enhancement are the major tools facilitating diagnosis of an intact aneurysm.

Lasers in neurosurgery: a review

In recent years neurosurgeons have shown an increasing interest in lasers. An understanding of the basic laser mechanism and tissue effects is important. CO2 laser is an excellent no-touch tool for excising and evaporating brain tumors. It has several other uses in neurosurgery both with free-hand technique and with microscope attachment and a micromanipulator. It is easier and more precise to manipulate a laser beam than any of the conventional instruments. Nd:YAG and argon lasers are more effective for coagulation of blood vessels and for dealing with vascular neoplasms. Microvascular anastamosis has been achieved with the use of Nd:YAG laser in experimental animals and has potential for practical application in extra-intracranial bypass operations. There are many advantages and some disadvantages to the use of lasers in neurosurgery.

Surgical treatment of unruptured intracranial aneurysms

The author has reviewed a series of 19 patients with unruptured aneurysms treated surgically during a 5-year period from 1976 to 1981. Unruptured aneurysms found in patients with multiple aneurysms and subarachnoid haemorrhage due to ruptured aneurysms are not included in this series. Literature on this subject is reviewed. There was no mortality and results were excellent in 7 patients with asymptomatic aneurysms. In 12 patient with symptomatic aneurysms there was no mortality and results were good to excellent in 9 patients. In 2 the results were unsatisfactory. The series included aneurysms varying in size from 5 mm to over 2.5 cm (giant aneurysm). Controversial aspects of surgery of unruptured intracranial aneurysms are discussed. The authors recommend surgical treatment of unruptured intracranial aneurysms regardless of size until such time when more definitive information is available about the natural history of these lesions.