Neuronal complex I deficiency occurs throughout the Parkinson's disease brain, but is not associated with neurodegeneration or mitochondrial DNA damage.

Mitochondrial complex I deficiency occurs in the substantia nigra of individuals with Parkinson's disease. It is generally believed that this phenomenon is caused by accumulating mitochondrial DNA damage in neurons and that it contributes to the process of neurodegeneration. We hypothesized that if these theories are correct, complex I deficiency should extend beyond the substantia nigra to other affected brain regions in Parkinson's disease and correlate tightly with neuronal mitochondrial DNA damage. To test our hypothesis, we employed a combination of semiquantitative immunohistochemical analyses, Western blot and activity measurements, to assess complex I quantity and function in multiple brain regions from an extensively characterized population-based cohort of idiopathic Parkinson's disease (n = 18) and gender and age matched healthy controls (n = 11). Mitochondrial DNA was assessed in single neurons from the same areas by real-time PCR. Immunohistochemistry showed that neuronal complex I deficiency occurs throughout the Parkinson's disease brain, including areas spared by the neurodegenerative process such as the cerebellum. Activity measurements in brain homogenate confirmed a moderate decrease of complex I function, whereas Western blot was less sensitive, detecting only a mild reduction, which did not reach statistical significance at the group level. With the exception of the substantia nigra, neuronal complex I loss showed no correlation with the load of somatic mitochondrial DNA damage. Interestingly, α-synuclein aggregation was less common in complex I deficient neurons in the substantia nigra. We show that neuronal complex I deficiency is a widespread phenomenon in the Parkinson's disease brain which, contrary to mainstream theory, does not follow the anatomical distribution of neurodegeneration and is not associated with the neuronal load of mitochondrial DNA mutation. Our findings suggest that complex I deficiency in Parkinson's disease can occur independently of mitochondrial DNA damage and may not have a pathogenic role in the neurodegenerative process.

Molecular pathogenesis of polymerase γ-related neurodegeneration.

OBJECTIVE: Polymerase gamma (POLG) mutations are a common cause of mitochondrial disease and have also been linked to neurodegeneration and aging. We studied the molecular mechanisms underlying POLG-related neurodegeneration using postmortem tissue from a large number of patients. METHODS: Clinical information was available from all subjects. Formalin-fixed and frozen brain tissue from 15 patients and 23 controls was studied employing a combination of histopathology, immunohistochemistry, and molecular studies of microdissected neurons. RESULTS: The primary consequence of POLG mutation in neurons is mitochondrial DNA depletion. This was already present in infants with little evidence of neuronal loss or mitochondrial dysfunction. With longer disease duration, we found an additional, progressive accumulation of mitochondrial DNA deletions and point mutations accompanied by increasing numbers of complex I-deficient neurons. Progressive neurodegeneration primarily affected the cerebellar systems and dopaminergic cells of the substantia nigra. Superimposed on this chronic process were acute, focal cortical lesions that correlated with epileptogenic foci and that showed massive neuronal loss. INTERPRETATION: POLG mutations appear to compromise neuronal respiration via a combination of early and stable depletion and a progressive somatic mutagenesis of the mitochondrial genome. This leads to 2 distinct but overlapping biological processes: a chronic neurodegeneration reflected clinically by progressive ataxia and cognitive impairment, and an acute focal neuronal necrosis that appears to be related to the presence of epileptic seizures. Our findings offer an explanation of the acute-on-chronic clinical course of this common mitochondrial encephalopathy.

Severe nigrostriatal degeneration without clinical parkinsonism in patients with polymerase gamma mutations.

The role of mitochondria in the pathogenesis of neurodegeneration is an area of intense study. It is known that defects in proteins involved in mitochondrial quality control can cause Parkinson's disease, and there is increasing evidence linking mitochondrial dysfunction, and particularly mitochondrial DNA abnormalities, to neuronal loss in the substantia nigra. Mutations in the catalytic subunit of polymerase gamma are among the most common causes of mitochondrial disease and owing to its role in mitochondrial DNA homeostasis, polymerase gamma defects are often considered a paradigm for mitochondrial diseases generally. Yet, despite this, parkinsonism is uncommon with polymerase gamma defects. In this study, we investigated structural and functional changes in the substantia nigra of 11 patients with polymerase gamma encephalopathy. We characterized the mitochondrial DNA abnormalities and examined the respiratory chain in neurons of the substantia nigra. We also investigated nigrostriatal integrity and function using a combination of post-mortem and in vivo functional studies with dopamine transporter imaging and positron emission tomography. At the cellular level, dopaminergic nigral neurons of patients with polymerase gamma encephalopathy contained a significantly lower copy number of mitochondrial DNA (depletion) and higher levels of deletions than normal control subjects. A selective and progressive complex I deficiency was seen and this was associated with a severe and progressive loss of the dopaminergic neurons of the pars compacta. Dopamine transporter imaging and positron emission tomography showed that the degree of nigral neuronal loss and nigrostriatal depletion were severe and appeared greater even than that seen in idiopathic Parkinson's disease. Despite this, however, none of our patients showed any signs of parkinsonism. The additional presence of both thalamic and cerebellar dysfunction in our patients suggested that these may play a role in counteracting the effects of basal ganglia dysfunction and prevent the development of clinical parkinsonism.

Different osteosyntheses for Colles' fracture: a mechanical study in 42 cadaver bones.

BACKGROUND AND PURPOSE: In recent years several different plate designs for internal fixation of fractures of the distal radius have been developed. However, few biomechanical studies have been performed to compare these new implants. The purpose of this study was to compare the mechanical properties of 5 different commercially available plates (3 volar and 2 dorsal) with standard K-wire fixation using a distal radial cadaver model. MATERIAL AND METHODS: 42 human radial bones from 26 cadavers were included. The bone mineral density (BMD) was measured by DEXA in all bones, and the radial bones were assigned to 6 equiv alent groups based on bone density and total amount of mineral. A distal radial osteotomy was done and a dorsal 30-degree wedge of bone was removed. 1 K-wire fixation group and 5 plate groups were tested for rigidity, yield load, and maximum load. RESULTS: When data from dorsally and volarly applied plates were pooled, we did not find any statistically significant differences between them regarding stiffness, yield load, and maximum load. The K-wire group showed significantly lower yield load than 3 of the plate groups. There were no statistically significant differences in yield load between the 5 plate groups. The K-wire group showed lower rigidity than the plate groups. The K-wire group and 1 plate group failed at a statistically significant lower maximum load than the 4 other plate groups. INTERPRETATION: The volar plates had the same mechanical stability as the dorsally applied plates, and they are therefore a good alternative to dorsally applied plates. K-wire osteosynthesis was inferior to plate osteosyntheses regarding all mechanical properties.

Defective mitochondrial DNA homeostasis in the substantia nigra in Parkinson disease.

Increased somatic mitochondrial DNA (mtDNA) mutagenesis causes premature aging in mice, and mtDNA damage accumulates in the human brain with aging and neurodegenerative disorders such as Parkinson disease (PD). Here, we study the complete spectrum of mtDNA changes, including deletions, copy-number variation and point mutations, in single neurons from the dopaminergic substantia nigra and other brain areas of individuals with Parkinson disease and neurologically healthy controls. We show that in dopaminergic substantia nigra neurons of healthy individuals, mtDNA copy number increases with age, maintaining the pool of wild-type mtDNA population in spite of accumulating deletions. This upregulation fails to occur in individuals with Parkinson disease, however, resulting in depletion of the wild-type mtDNA population. By contrast, neuronal mtDNA point mutational load is not increased in Parkinson disease. Our findings suggest that dysregulation of mtDNA homeostasis is a key process in the pathogenesis of neuronal loss in Parkinson disease.

[Treatment of patients with gastrointestinal stromal tumour with imatinib mesylate]. / Behandling med imatinibmesylat av pasienter med gastrointestinal stromal tumor.

BACKGROUND: Gastrointestinal stromal tumour (GIST) is the most frequent mesenchymal tumour type of the digestive tract. Between 30 and 40% of patients have high-risk, malignant GIST with poor prognosis after surgery. Imatinib mesylate is a recently introduced KIT tyrosine kinase inhibitor with effect on metastatic GIST. We report our experience with imatinib mesylate in the treatment of GIST. MATERIAL AND METHODS: Nine patients diagnosed with GIST have received imatinib mesylate since August 2001. Eight patients had metastatic disease, one patient received adjuvant treatment. The patients were evaluated according to standard protocols for clinical performance, effect of treatment, and adverse effects. Tumour tissue was analysed for mutational status in KIT and PDGFRA. RESULTS: All patients with metastatic disease had palliative benefit; three had partial response and the remaining stable disease. The single patient receiving adjuvant treatment had no sign of recurrence. Side effects were mainly mild diarrhoea, nausea and vomiting. Seven patients had mutations in KIT exon 11, one in KIT exon 9, and one in PDGFRA exon 12. INTERPRETATION: The results demonstrate that imatinib mesylate is an effective drug that can stabilise and reduce disease in patients with advanced GIST.

Concomitant inactivation of the p53- and pRB- functional pathways predicts resistance to DNA damaging drugs in breast cancer in vivo.

Chemoresistance is the main obstacle to cancer cure. Contrasting studies focusing on single gene mutations, we hypothesize chemoresistance to be due to inactivation of key pathways affecting cellular mechanisms such as apoptosis, senescence, or DNA repair. In support of this hypothesis, we have previously shown inactivation of either TP53 or its key activators CHK2 and ATM to predict resistance to DNA damaging drugs in breast cancer better than TP53 mutations alone. Further, we hypothesized that redundant pathway(s) may compensate for loss of p53-pathway signaling and that these are inactivated as well in resistant tumour cells. Here, we assessed genetic alterations of the retinoblastoma gene (RB1) and its key regulators: Cyclin D and E as well as their inhibitors p16 and p27. In an exploratory cohort of 69 patients selected from two prospective studies treated with either doxorubicin monotherapy or 5-FU and mitomycin for locally advanced breast cancers, we found defects in the pRB-pathway to be associated with therapy resistance (p-values ranging from 0.001 to 0.094, depending on the cut-off value applied to p27 expression levels). Although statistically weaker, we observed confirmatory associations in a validation cohort from another prospective study (n = 107 patients treated with neoadjuvant epirubicin monotherapy; p-values ranging from 7.0 × 10(-4) to 0.001 in the combined data sets). Importantly, inactivation of the p53-and the pRB-pathways in concert predicted resistance to therapy more strongly than each of the two pathways assessed individually (exploratory cohort: p-values ranging from 3.9 × 10(-6) to 7.5 × 10(-3) depending on cut-off values applied to ATM and p27 mRNA expression levels). Again, similar findings were confirmed in the validation cohort, with p-values ranging from 6.0 × 10(-7) to 6.5 × 10(-5) in the combined data sets. Our findings strongly indicate that concomitant inactivation of the p53- and pRB- pathways predict resistance towards anthracyclines and mitomycin in breast cancer in vivo.

Deaths after intravenous misuse of transdermal fentanyl.

Fentanyl is a potent synthetic opioid used as a general anesthetic and analgetic. Fatal outcome from intravenous misuse of transdermal fentanyl is rare, and there are few such reports in literature. Here we report two cases of fatal intravenous injection of the content from fentanyl patches. Both were male drug addicts, found dead within a one week interval in the same apartment. Post-mortem femoral blood was screened for amphetamines, cannabinoids, cocaine, and opioids with immunological methods (EMIT II) and further with headspace gas chromatography for alcohol and with liquid chromatography mass spectrometry (LC-MS) for different drugs, including fentanyl. Confirmatory analysis of fentanyl and morphine was performed by gas chromatography-mass spectrometry (GC-MS). In the first case, the toxicological analysis revealed fentanyl (2.7 ng/mL), morphine (31.4 ng/mL), and ethanol (1.1 g/L) in postmortem blood and amphetamine, cannabinoids, morphine, and ethanol (1.4 g/L) in postmortem urine. In the second case, the analysis revealed fentanyl (13.8 ng/mL), 7-aminoclonazepam (57.1 ng/mL), and sertralin (91.9 ng/mL) in postmortem blood and a small amount of ethanol (0.1 g/L) in postmortem urine. Police investigation revealed that both the deceased had bought the patches from the same source. The present cases demonstrate the possibility of intravenous misuse of transdermal patches and the risk of fatal outcome.

Fatal injury as a function of rurality-a tale of two Norwegian counties.

BACKGROUND: Many studies indicate rural location as a separate risk for dying from injuries. For decades, Finnmark, the northernmost and most rural county in Norway, has topped the injury mortality statistics in Norway. The present study is an exploration of the impact of rurality, using a point-by-point comparison to another Norwegian county. METHODS: We identified all fatalities following injury occurring in Finnmark between 2000 and 2004, and in Hordaland, a mixed rural/urban county in western Norway between 2003 and 2004 using data from the Norwegian Cause of Death Registry. Intoxications and low-energy trauma in patients aged over 64 years were excluded. To assess the effect of a rural locale, Hordaland was divided into a rural and an urban group for comparison. In addition, data from Statistics Norway were analysed. RESULTS: Finnmark reported 207 deaths and Hordaland 217 deaths. Finnmark had an injury death rate of 33.1 per 100,000 inhabitants. Urban Hordaland had 18.8 deaths per 100,000 and rural Hordaland 23.7 deaths per 100,000. In Finnmark, more victims were male and were younger than in the other areas. Finnmark and rural Hordaland both had more fatal traffic accidents than urban Hordaland, but fewer non-fatal traffic accidents. CONCLUSIONS: This study illustrates the disadvantages of the most rural trauma victims and suggests an urban-rural continuum. Rural victims seem to be younger, die mainly at the site of injury, and from road traffic accident injuries. In addition to injury prevention, the extent and possible impact of lay people's first aid response should be explored.

Different mechanisms of decapitation: three classic and one unique case history.

Three classic cases and one exceptional case are reported. The unique case of decapitation took place in a traffic accident, while the others were seen after homicide, vehicle-assisted suicide, and after long-jump hanging. Thorough scene examinations were performed, and photographs from the scene were available in all cases. Through the autopsy of each case, the mechanism for the decapitation in each case was revealed. The severance lines were through the neck and the cervical vertebral column, except for in the motor vehicle accident case, where the base of skull was fractured. This case was also unusual as the mechanism was blunt force. In the homicide case, the mechanism was the use of a knife combined with a saw, while in the two last cases, a ligature made the cut through the neck. The different mechanisms in these decapitations are suggested.

Unnatural death in the elderly : A forensic study from western norway.

The objective of the study was to determine the unnatural manner and causes of death in older people, defined as individuals at least 60 years of age at the time of death. A series of medico-legally examined deaths in older people, who were examined between January 1, 1999 and December 31, 2003, and whose deaths were considered unnatural after forensic examination were studied. All deaths took place in western Norway, in two whole counties and the north part of a third county, including one large Norwegian city and one medium-sized city on the west coast of Norway. Of the 2425 forensic examinations performed in the time period, 1169 were 60 years or older at the time of death. Of these, 228 deaths were categorized as accidental, suicidal, or homicidal. Drowning was the most common lethal accident in elderly males, whereas fatal traffic accidents were more frequent in women. Alcohol intoxication was very common among male drowning victims, and none of the drowning victims had used a life-saving floating device. None of the elderly traffic victims were intoxicated. Death after a falling accident in the home is probably underreported. Suicide is more common among elderly men than women. Among men, hanging was the most common cause of death, whereas intoxication resultiong from drug overdose and drowning were the most frequent causes of death in women. Cancer was present in 19% of the suicide victims, all men. Serious disease may be a predisposing factor for suicidal behavior. Homicide is uncommon as a manner of unnatural death among the elderly.