Admission patterns and survival from status epilepticus in critical care in the UK: an analysis of the Intensive Care National Audit and Research Centre Case Mix Programme database.

BACKGROUND AND PURPOSE: Factors influencing the outcome after the critical care unit (CCU) for patients with status epilepticus (SE) are poorly understood. Survival for these patients was examined to establish (i) whether the risk of mortality has changed over time and (ii) whether admission to different unit types affects mortality risk over and above other risk factors. METHODS: The Intensive Care National Audit and Research Centre database and the Case Mix Programme database (January 2001 to December 2016) were analysed. Units were defined as neuro-CCU (NCCU), general CCU with 24-h neurological support (GCCU-N) or general CCU with limited neurological support (GCCU-L). RESULTS: There were 35 595 CCU cases of SE with a 3-fold increase over time (4739 in 2001-2004 to 14 166 in 2013-2016). More recent admissions were older and were more often unsedated on admission. Mortality declined for all units although this was more marked for NCCUs (8.1% in 2001-2004 to 4.4% in 2013-2016 compared to 5.1% and 4.1% for GCCU-L). Acute hospital mortality was two to three times higher than CCU mortality although this has also declined with time. GCCU-L appeared to have lower mortality than NCCUs (odds ratio 0.84, 95% confidence interval 0.72, 0.98) but after post hoc adjustment for case mix there were no differences. Older age and markers of seriousness of morbidity were all associated with increased mortality risk. CONCLUSIONS: The number of patients admitted to a CCU for SE is rising but critical care and acute hospital mortality is decreasing. Patients treated in an NCCU have higher mortality but this is explicable by more severe underlying disease.

Caspase-2: controversial killer or checkpoint controller?

The caspases are an evolutionarily conserved family of cysteine proteases, with essential roles in apoptosis or inflammation. Caspase-2 was the second caspase to be cloned and it resembles the prototypical nematode caspase CED-3 more closely than any other mammalian protein. An absence of caspase-2-specific reagents and the subtle phenotype of caspase-2-deficient mice have hampered definition of the physiological role of caspase-2 and identification of factors regulating its activity. Although some data implicate caspase-2 in apoptotic pathways, a link with apoptosis has been less firmly established for caspase-2 than for some other caspases. Emerging evidence suggests that caspase-2 regulates the cell cycle and may act as a tumour suppressor. This article critically reviews the current state of knowledge regarding the biochemistry and biology of this controversial caspase.

DNA repair in response to anthracycline-DNA adducts: a role for both homologous recombination and nucleotide excision repair.

Doxorubicin, a widely used anthracycline anticancer agent, acts as a topoisomerase II poison but can also form formaldehyde-mediated DNA adducts. This has led to the development of doxorubicin derivatives such as doxoform, which can readily form adducts with DNA. This work aimed to determine which DNA repair pathways are involved in the recognition and possible repair of anthracycline-DNA adducts. Cell lines lacking functional proteins involved in each of the five main repair pathways, mismatch repair (MMR), base excision repair (BER), nucleotide excision repair (NER), homologous recombination (HR) and non-homologous end-joining (NHEJ) were examined for sensitivity to various anthracycline adduct-forming treatments. The treatments used were doxorubicin, barminomycin (a model adduct-forming anthracycline) and doxoform (a doxorubicin-formaldehyde conjugate). Cells with deficiencies in MMR, BER and NHEJ were equally sensitive to adduct-forming treatments compared to wild type cells and therefore these pathways are unlikely to play a role in the repair of these adducts. Some cells with deficiencies in the NER pathway (specifically, those lacking functional XPB, XPD and XPG), displayed tolerance to adducts induced by both barminomycin and doxoform and also exhibited a decreased level of apoptosis in response to adduct-forming treatments. Conversely, two HR deficient cell lines were shown to be more sensitive to barminomycin and doxoform than HR proficient cells, indicating that this pathway is also involved in the repair response to anthracycline-DNA adducts. These results suggest an unusual damage response pathway to anthracycline adducts involving both NER and HR that could be used to optimise cancer therapy for tumours with either high levels of NER or defective HR. Tumours with either of these characteristics would be predicted to respond particularly well to anthracycline-DNA adduct-forming treatments.

Formaldehyde-releasing prodrugs in combination with adriamycin can overcome cellular drug resistance.

The anticancer drug Adriamycin is widely used in cancer chemotherapy and is classified as a topoisomerase II inhibitor. However, in the presence of formaldehyde, Adriamycin also forms high levels of DNA adducts. In this study, a new series of butyric acid and formaldehyde-releasing drugs related to AN9 (pivaloyloxymethyl butyrate) was assessed for their ability to facilitate Adriamycin-DNA adduct formation in Adriamycin-sensitive and -resistant cell lines (HL60 and HL60/MX2; MES-SA and MES-SA/Dx5). Drugs that released two molar equivalents of formaldehyde per mole of prodrug were superior in their ability to enhance adduct formation compared to those that released one molar equivalent. Adduct formation (as assessed by binding of radiolabeled Adriamycin to genomic DNA) was always lower in the resistant cell lines compared to the sensitive cell lines. However, in growth inhibition experiments, prodrug combinations were able to overcome Adriamycin resistance to varying degrees, and the combination of Adriamycin with selected prodrugs that release two moles of formaldehyde totally overcame resistance in HL60/MX2 cells. These HL60-derived cells express altered levels of topoisomerase II and also express a mutant form of the enzyme. Combinations of Adriamycin with selected prodrugs that release one or two moles of formaldehyde partially overcame P-glycoprotein-mediated resistance in MES-SA/Dx5 cells. Formaldehyde-releasing prodrugs (as single agents) overcame both forms of resistance in the two resistant cell lines, demonstrating that they were not substrates of these resistance mechanisms. Collectively, these results suggest that changing the mechanism via which Adriamycin exerts its anticancer effect by dramatically increasing adduct levels (requiring coadministration of formaldehyde-releasing prodrugs) may be a useful means of cancer treatment, as well as for overcoming Adriamycin-induced resistance.

Modafinil for excessive daytime sleepiness in myotonic dystrophy.

The authors conducted an open-label trial of modafinil for excessive daytime sleepiness in myotonic dystrophy. Eleven patients were evaluated: two were not treated because of obstructive sleep apnea, and nine received 200 to 400 mg modafinil/day for an average of 16.4 weeks. There were no major side effects. Average sleep latency as measured by the Multiple Sleep Latency Test increased from 7.3 to 22.7 minutes ( p = 0.00013), and average Epworth Sleepiness Scale score decreased from 13.25 to 7.75 (p = 0.01028). Modafinil shows evidence of effectiveness for excessive daytime somnolence in myotonic dystrophy and should be investigated further.

VACTERL with the mitochondrial np 3243 point mutation.

The VACTERL association of vertebral, anal, cardiovascular, tracheo-esophageal, renal, and limb defects is one of the more common congenital disorders with limb deficiency arising during blastogenesis. The cause is probably heterogeneous; a molecular basis has not yet been defined. We report on a family in which a female infant with VACTERL was born in 1977 and died at age 1 month due to renal failure. Because her mother and sister later developed classical mitochondrial cytopathy associated with the A-G point mutation at nucleotide position (np) 3243 of mitochondrial (mt) DNA, we performed a molecular analysis of mt DNA in preserved kidney tissue from the VACTERL case. We discovered 100% mutant mt DNA in multicystic and 32% mutant mt DNA in normal kidney tissue. Mild deficiency of complex I respiratory chain enzyme activity was found in the mother's muscle biopsy. Other maternal relatives were healthy but had low levels of mutant mt DNA in blood. This is the first report to provide a precise molecular basis for a case of VACTERL. The differing tissue pathology depending on the percentage of mutant mt DNA suggests a causal connection between the mutation and symptoms. VACTERL, and this type of multicystic renal dysplasia, are new phenotypes for the np 3243 point mutation. The possibility of a mitochondrial disorder should be born in mind and also that VACTERL may occur as a first manifestation of a mutation that has been present for generations. This would have major implications for patient management and for genetic counselling regarding both the risk of recurrence and risk of other mitochondrial syndromes in affected families.

Brain disease and molecular analysis in myotonic dystrophy.

Abnormal amplification of a CTG repeat on chromosome 19 is the molecular basis of myotonic dystrophy (DM). Expansion of the repeat has been correlated with severity of several clinical features of the disease. We performed extensive cognitive testing, cerebral magnetic resonance imaging (MRI) and a molecular analysis in 28 cases of DM to determine the relationship between the molecular defect and brain disease. Performance in two or more cognitive tests was pathological in 10 cases. Fourteen patients had subcortical white matter lesions on MRI, 14 had cerebral atrophy. Amplification of the CTG repeat showed a strong correlation with cognitive test deficits when exceeding a length of over 1000 trinucleotides. MRI lesions were associated with impaired psychometric performance, but MRI and molecular findings were only weakly related. Disease duration influenced the appearance and amount of white matter lesions on MRI. Quantification of CTG repeat size may allow an early estimate on the probability of brain involvement in DM; cognitive dysfunction is associated with white matter lesions and cerebral atrophy later on in the course.

Magnetic resonance imaging of muscle and brain in myotonic dystrophy.

Myotonic dystrophy (MD) is characterized by myotonia, weakness and extramuscular symptoms, including intellectual impairment. We performed magnetic resonance imaging (MRI) of brain and muscle in 25 MD patients: 81% had cerebral atrophy (severe in 36%); 68% had focal white matter lesions, which were large and multiple in 27%. Brain MRI findings correlated with mental impairment; the severity of both correlated with disease duration. Changes in brain and muscle MRI were progressive with time, but independent of each other. Muscle MRI findings were fatty degeneration and loss of bulk. In the calves, the medial gastrocnemius muscles were involved earliest and the posterior tibial muscles relatively spared. In the thighs the vastus muscles were damaged most often and the rectus femoris least. Focal muscle damage was efficiently visualized, sometimes preceding clinical detection. Muscle MRI was less sensitive than conventional methods for early diagnosis, but ideal for follow-up, owing to its non-invasiveness and examiner-independence.

Stroke-like episodes in familial mitochondrial encephalomyopathy: clinical and biochemical aspects.

Acute episodes of focal neurological dysfunction are a well-recognized complication of the mitochondrial encephalomyopathies. Because of rapid remission, biochemical tests and other diagnostic procedures are mostly performed after the acute phase. We report the case of a patient suffering from mitochondrial disease manifesting primarily with seizures, progressive deafness and dementia, who experienced multiple stroke-like episodes. Other members of the family with evidence of mitochondrial dysfunction are presented briefly. EEG and biochemical findings in the acute stage are correlated with clinical symptoms, showing characteristics distinct from the chronic illness. The possible involvement of dietary factors in the provocation of stroke-like episodes is discussed and regulation of glucose intake suggested as a strategy in the prevention of stroke-like episodes.

Spinocerebellar ataxia, type 3 (SCA3) is genetically identical to Machado-Joseph disease (MJD).

Spinocerebellar ataxia, type 3 (SCA3) and Machado-Joseph disease (MJD) are two clinically distinct representatives of the heterogeneous group of autosomal dominant cerebellar ataxias. Assignment of the disease genes to the same region of the long arm of chromosome 14 in both SCA3 and MJD suggested that these two disorders are genetically identical. The recent identification of a trinucleotide (CAG) repeat expansion in a gene underlying MJD facilitates assessment of this hypothesis. We analysed the MJD gene in members of a family with characteristic features of SCA3 and no symptoms typical of MJD. We found the same trinucleotide repeat expansion within the gene that was previously described in patients with MJD. The findings demonstrate that SCA3 and MJD are genetically identical in spite of their pronounced clinical differences. Furthermore, we demonstrate a striking variation in the copy number of the CAG repeat among affected members of the same family.

Detection of labile anthracycline-DNA adducts by real-time PCR.

Barminomycin was employed as a model anthracycline that yields thermally stable drug-DNA adducts. Real-time PCR was utilized for the detection of these barminomycin-DNA adducts at drug levels as low as 100 nM in a cell-free assay system, with the lowest level of detection at approximately 20 nM. By contrast, doxorubicin-DNA adducts are heat labile and their levels were underestimated by conventional real-time PCR unless the DNA denaturation temperature was lowered by the addition of glycerol. Doxorubicin-DNA adduct levels of 5.5 per 10 kb were detected by real-time PCR (in the presence of 24% glycerol) following treatment with 0.5 microM doxorubicin (and 2 mM formaldehyde), considerably more sensitive than that detected by a gene-specific Southern-based procedure. Both the absolute fluorescence intensity in the linear PCR amplification range and the crossing point method provided useful dose-dependent estimates of adduct levels. The time required for a complete real-time PCR analysis of drug-induced adduct levels was approximately 40 min, and this may ultimately provide oncologists with a rapid means with which to monitor drug-DNA adduct levels in patients under treatment with anthracyclines. Responses to these drugs could be quickly and efficiently monitored in patients, thereby facilitating optimization of drug dosages as well as early detection of resistance to these agents.

Multidrug resistance in glioblastoma. Chemosensitivity testing and immunohistochemical demonstration of P-glycoprotein.

Chemosensitivity of previously untreated glioblastomas to mitoxantrone, methotrexate, ACNU and BCNU was tested on cultured tissue. Sixteen of 62 tumors were partially chemosensitive in vitro. The monoclonal antibody C 219 was used to demonstrate the presence of p-glycoprotein in the 16 sensitive and five highly resistant glioblastomas. All 21 tumors identically expressed p-glycoprotein. These results show that untreated glioblastomas primarily express p-glycoprotein even if they are at least partially chemosensitive in vitro. Therefore, immunohistochemical demonstration of p-glycoprotein with the monoclonal antibody C 219 can not provide reliable information on short term resistance of the individual tumors to antineoplastic drugs. P-glycoprotein expression could, however, help to explain the disappointing overall long-term efficacy of chemotherapy by showing the existence of cell populations with early drug resistance in these tumors.

Mutations in MYH7 cause Multi-minicore Disease (MmD) with variable cardiac involvement.

Central Core Disease (CCD) and Multi-minicore Disease (MmD) (the "core myopathies") have been mainly associated with mutations in the skeletal muscle ryanodine receptor (RYR1) and the selenoprotein N (SEPN1) gene. A proportion of cases remain unresolved. Mutations in MYH7 encoding the beta myosin heavy chain protein have been implicated in cardiac and, less frequently, skeletal muscle disorders. Here we report four patients from two families with a histopathological diagnosis of MmD, presenting in childhood with slowly progressive muscle weakness, more proximal in Family 1 and more distal in Family 2, and variable degrees of cardiorespiratory impairment evolving later in life. There was also a strong family history of sudden death in the first family. Muscle biopsies obtained in early childhood showed multiple minicores as the most prominent feature. Sequencing of the MYH7 gene revealed heterozygous missense mutations, c.4399C>G; p.Leu1467Val (exon 32) in Family 1 and c.4763G>C; p.Arg1588Pro (exon 34) in Family 2. These findings suggest MYH7 mutations as another cause of a myopathy with multiple cores, in particular if associated with dominant inheritance and cardiac involvement. However, clinical features previously associated with this genetic background, namely a more distal distribution of weakness and an associated cardiomyopathy, may only evolve over time.

Bilateral near infrared spectroscopy in space-occupying middle cerebral artery stroke.

BACKGROUND: The crucial importance of monitoring both the infarcted and non-infarcted hemispheres in management of space occupying middle cerebral artery (MCA) infarction is increasingly recognized, but optimal technique is debated. We investigated the potential for bilateral Near Infrared Spectroscopy (NIRS) to non-invasively provide relevant information on intracranial oxygenation. METHODS: In patients with complete MCA stroke and brain swelling NIRS optodes were placed over both frontal lobes and regional cerebral oxygen saturation (rSO(2)) was measured at 30 s intervals for at least 12 h. The bilateral pattern of changes in rSO(2) was analysed with respect to clinical course and development of brain swelling, and patients compared according to outcome. RESULTS: A total of 24 patients were analysed, of whom 13 underwent decompressive hemicraniectomy; outcome was good (GOS > or = 3) in 11 cases, and poor (GOS < 3) in 13. Absolute rSO(2) values varied widely and did not correlate with clinical data. The average difference in rSO(2) (rSO(2)-diff) between infarcted and contralateral hemisphere was 10.7% and higher on the infarct side in 22/24 cases. The rSO(2)-diff typically decreased with brain swelling, disappeared in patients who developed herniation, but increased markedly after successful craniectomy and management of brain swelling. The rSO(2)-diff at the end of monitoring was significantly higher in good outcome survivors. The time pattern of rSO(2)-diff can be explained by alterations of perfusion and O(2)-consumption depending on hemispheric swelling. CONCLUSION: Bilateral NIRS may provide more useful information on cerebral oxygenation than unilateral measurements and its clinical validity to help predict worsening of brain swelling should be investigated further.

Subcutaneous microdialysis in mitochondrial cytopathy.

We present the results of subcutaneous microdialysis, a new minimally invasive biochemical monitoring technique, in mitochondrial cytopathy. We studied 6 ambulatory patients with mitochondrial cytopathy and 6 controls without mitochondrial disease using a subcutaneous probe for continuous microdialysis, and obtained measurements of lactate, pyruvate, and glucose from samples gathered at 30-60 min intervals during the day and at 3-h intervals at night. The lactate:pyruvate ratio (LPR) was calculated and related to disease severity and metabolic stress. Microdialysis was well tolerated. Controls had stable lactate and pyruvate values in the normal range and a low LPR (average values between 0.0114 and 0.0145). Patients had widely fluctuating lactate and pyruvate values, a higher average LPR between 0.0187 and 0.0724, and marked diurnal variation, especially in the severely affected patients. Increases in the LPR coincided with metabolic stress in individual cases. We conclude that subcutaneous microdialysis is well tolerated and enables continuous metabolic monitoring of patients with mitochondrial cytopathy. It has particular potential for use in the identification of metabolic risk factors and may help to assess the impact of therapeutic regimens.

Locus heterogeneity in Friedreich ataxia.

Friedreich ataxia (FRDA) is the most common form of autosomal recessive ataxia. The disease locus was assigned to chromosome 9 and the disease gene, STM7/X25, has been isolated. To date most data suggest locus homogeneity in FRDA. We now provide strong evidence of a second FRDA locus. Studying two siblings with FRDA from two families we did not detect a mutation in STM7/X25. Haplotype analysis of the STM7/X25 region of chromosome 9 demonstrated that the relevant portion of chromosome 9 differs in the patients. Although the patients studied had typical FRDA, one sibpair had the uncommon symptom of retained tendon reflexes. In order to investigate whether retained tendon reflexes are characteristic of FRDA caused by the second locus, FRDA2, we studied an unrelated FRDA patient with retained tendon reflexes. The observation of typical mutations in STM7/X25 (GAA expansions) in this patient demonstrates that the two genetically different forms of FRDA cannot be distinguished clinically.