Polymorphisms in dopamine-associated genes and cognitive decline in Parkinson's disease.

OBJECTIVES: Cognitive decline is common in Parkinson's disease (PD), but the underlying mechanisms for this complication are incompletely understood. Genotypes affecting dopamine transmission may be of importance. This study investigates whether genotypes associated with reduced prefrontal dopaminergic tone and/or reduced dopamine D2-receptor availability (Catechol-O-methyltransferase [COMT] Val158 Met genotype and DRD2 C957 T genotype) affect the development of cognitive deficits in PD. MATERIALS AND METHODS: One hundred and 34 patients with idiopathic PD, participating in a regional, population-based study of incident parkinsonism, underwent genotyping. After extensive baseline investigations (including imaging and biomarker analyses), the patients were followed prospectively during 6-10 years with neuropsychological evaluations, covering six cognitive domains. Cognitive decline (defined as the incidence of either Parkinson's disease mild cognitive impairment [PD-MCI] or dementia [PDD], diagnosed according to published criteria and blinded to genotype) was studied as the primary outcome. RESULTS: Both genotypes affected cognition, as shown by Cox proportional hazards models. While the COMT 158 Val/Val genotype conferred an increased risk of mild cognitive impairment in patients with normal cognition at baseline (hazard ratio: 2.13, P = .023), the DRD2 957 T/T genotype conferred an overall increased risk of PD dementia (hazard ratio: 3.22, P < .001). The poorer cognitive performance in DRD2 957 T/T carriers with PD occurred mainly in episodic memory and attention. CONCLUSIONS: The results favor the hypothesis that dopamine deficiency in PD not only relate to mild cognitive deficits in frontostriatal functions, but also to a decline in memory and attention. This could indicate that dopamine deficiency impairs a wide network of brain areas.

Deaths caused by injury among people of working age (18-64) are decreasing, while those among older people (64+) are increasing.

BACKGROUND: Injury is an important cause of death in all age groups worldwide, and contributes to many losses of human and economic resources. Currently, we know a few data about mortality from injury, particularly among the working population. The aim of the present study was to examine death from injury over a period of 14 years (1999-2012) using the Swedish Cause of Death Registry (CDR) and the National Patient Registry, which have complete national coverage. METHOD: CDR was used to identify injury-related deaths among adults (18 years or over) during the years 1999-2012. ICD-10 diagnoses from V01 to X39 were included. The significance of changes over time was analyzed by linear regression. RESULTS: The incidence of prehospital death decreased significantly (coefficient -0.22, r 2 = 0.30; p = 0.041) during the study period, while that of deaths in hospital increased significantly (coefficient 0.20, r 2 = 0.75; p < 0.001). Mortality/100,000 person-years in the working age group (18-64 years) decreased significantly (coefficient -0.40, r 2 = 0.37; p = 0.020), mainly as a result of decrease in traffic-related deaths (coefficient -0.34, r 2 = 0.85; p < 0.001). The incidence of deaths from injury among elderly (65 years and older) patients increased because of the increase in falls (coefficient 1.71, r 2 = 0.84; p < 0.001) and poisoning (coefficient 0.13, r 2 = 0.69; p < 0.001). CONCLUSION: The epidemiology of injury in Sweden has changed during recent years in that mortality from injury has declined in the working age group and increased among those people 64 years old and over.

Change in child mortality patterns after injuries in Sweden: a nationwide 14-year study.

INTRODUCTION: Sweden has one of the world's lowest child injury mortality rates, but injuries are still the leading cause of death among children. Child injury mortality in the country has been declining, but this decline seems to decrease recently. Our objective was therefore to further examine changes in the mortality of children's death from injury over time and to assess the contribution of various effects on mortality. The underlying hypothesis for this investigation is that the incidence of lethal injuries in children, still is decreasing and that this may be sex specific. PATIENTS AND METHODS: We studied all deaths from injury in Sweden under-18-year-olds during the 14 years 1999-2012. We identified those aged under 18 whose underlying cause of death was recorded as International Classification of Diseases, 10th Revision (ICD-10) diagnosis from V01 to X39 in the Swedish cause of death, where all dead citizens are registered. RESULTS: From the 1 January 1999 to 31 December 2012, 1213 children under the age of 18 died of injuries in Sweden. The incidence declined during this period (r = -0.606, p = 0.02) to 3.3 deaths/100,000 children-years (95 % CI 2.6-4.2). Death from unintentional injury was more common than that after intentional injury (p < 0.0001). There was a reduction in the incidence of unintentional injuries during the study period (r = -0.757, p = 0.03). The most common causes of death were injury to the brain (n = 337, 41 %), followed by drowning (n = 109, 13 %). The number of deaths after intentional injury increased (r = 0.585, p = 0.03) and at the end of the period was 1.5 deaths/100,000 children-years. The most common causes of death after intentional injuries were asphyxia (n = 177, 45 %), followed by injury to the brain (n = 76, 19 %). DISCUSSION: Mortality patterns in injured children in Sweden have changed from being dominated by unintentional injuries to a more equal distribution between unintentional and intentional injuries as well as between sexes and the overall rate has declined further. These findings are important as they might contribute to the preventive work that is being done to further reduce mortality in injured children.

Psychiatric complications and comorbidities in medical inpatients: the inadequacy of attestation at discharge.

The determination of an appropriate level of prospective payment for inpatient medical services requires consideration and documentation of psychiatric problems which impact on resource utilization. A major source of information for reimbursement planning is the list of secondary diagnoses referred to as "complications and comorbidities" (CCs) taken from the medical record. If psychiatry problems are omitted on the attestation sheet, they are unlikely to be included in any reimbursement formulae. This study was designed to look at actual hospital experience in terms of how often psychiatric diagnoses were attested to on the medical record. Of the 100 patients evaluated, 25 were found to have 33 psychiatric complications and CCs. Of the 33 psychiatric CCs, only 9 (24%) were recorded on the attestation sheet. Reasons for and implications of this low rate of attestation are discussed. The complete and accurate attestation of psychiatric problems may be the single most important priority for psychiatrists in general hospitals. Even when the DRG system is replaced by capitation payment, the importance of accurate diagnostic recording and recognition will remain paramount to making rate analyses and adjustments.

Nucleotide sequence of the structural gene for dihydroorotase of Escherichia coli K12.

The nucleotide sequence of the dihydroorotase structural gene, pyrC, of Escherichia coli K12 has been determined. The DNA sequence predicts a polypeptide chain of 347 amino acid residues corresponding in size and composition to the previously purified dihydroorotase subunit. Nuclease S1 mapping indicated that transcription of pyrC is initiated around 40 base pairs upstream from the translational start. The transcriptional leader region contains a region of dyad symmetry, which allows a stable hairpin to be formed. This sequence may have regulatory functions since similar structures are found in other pyr genes. The nucleotide sequence also contains a 186-codon open reading frame in front of pyrC. Nuclease Bal31-deletion derivatives of pyrC plasmids indicate that this gene does not affect the expression of pyrC. The predicted polypeptide chain shows a putative signal sequence. Downstream from the structural gene a sequence similar to a rho-independent transcriptional terminator is found. This unknown gene may thus encode a membrane protein of unknown function.

Oxidation-reduction potential of soluble and membrane-bound rabbit liver microsomal cytochrome P-450 LM2.

The redox midpoint potentials of rabbit liver microsomal cytochromes P-450 and of soluble and membrane-bound rabbit liver microsomal cytochrome P-450 LM2 were determined using EPR-spectroscopy and absorption difference spectrometry with NADPH or dithionite as reductants. Using EPR, a redox midpoint potential of -0.36 V was obtained both for the low spin and the high spin components of microsomal cytochrome P-450. Spectrophotometrical determinations yielded very similar values: -0.37 V and -0.34 V for the low and high spin signals, respectively. Soluble cytochrome P-450 LM2 had a midpoint potential of -0.32 V. This redox potential was not significantly affected by incorporation of the protein into an artificial membrane structure or, furthermore, by the presence of cytochrome b5 the same membrane.

Mitochondrial iron not bound in heme and iron-sulfur centers. Estimation, compartmentation and redox state.

A method is described for the assay of total mitochondrial non-heme iron and a fraction which does not belong to the iron-sulfur proteins (FeS centers) of the outer and inner membrane. The assay of the latter fraction, which is termed 'non-heme non-FeS iron', is based on the formation of a chelate of Fe(II) with bathophenanthroline sulfonate in osmotically swollen mitochondria under conditions where the FeS centers are quite stable as determined by EPR spectroscopy at 20.4 K, 93 K and 123 K. The 'non-heme non-FeS iron', which in normal rat liver mitochondria amounts to approx. one third of the total mitochondrial iron (i.e. 1.7 +/- 0.3 nmol . mg-1 protein), does not represent a homogeneous pool of iron. Based on studies of its reaction with bathophenanthroline sulfonate and the dependency of this reaction on reducing agents in mitochondria and mitoplasts, evidence is presented that this non-heme iron is present in two major pools in which the inner membrane constitutes the barrier. A minor fraction (i.e. 0.4 +/- 0.2 nmol . mg-1 protein) is localized to the 'outer' compartment and a major fraction (i.e. 1.1 +/- 0.1 nmol . mg-1 protein) is localized to the 'inner' compartment and is equally distributed between the inner membrane and the matrix. The experiments described in this study also indicate that approximately half of the 'non-heme non-FeS iron' of the 'inner' pool is in the ferrous form in mitochondria as isolated, and this was not increased when oxidizable substrates were added to the mitochondria. Although the biological significance of this iron pool is not yet clear, it is likely that it represents a transit iron pool being the proximate iron donor for heme synthesis catalyzed by the enzyme ferrochelatase.

Electron paramagnetic resonance of the copper in dopamine beta-monooxygenase. Rapid reduction by ascorbate, the steady-state redox level, chelation with EDTA, and reactivation of the apoenzyme by added copper.

The water-soluble form of dopamine beta-monooxygenase from bovine adrenal medulla was studied. Addition of excess CuSO4 to purified enzyme preparations followed by extensive ultrafiltration against copper-free buffer at pH 7.0, gave preparations with about four copper atoms per enzyme tetramer of Mr 290 000. The enzyme-bound copper was shown by the rapid-freeze technique and electron paramagnetic resonance (EPR) to be reduced by ascorbate at a rate which was faster than the overall catalytic rate; about 10% of the copper was oxidized to Cu(II) during steady-state catalysis in the presence of excess ascorbate. These results support an electron-transfer function of the enzyme-bound copper during catalysis and indicate that the reduction by ascorbate is not the rate-limiting step. The enzyme-bound copper was rapidly chelated by EDTA at pH 7.0., and the apoenzyme thus obtained after dialysis revealed no EPR-detectable copper. Addition of CuSO4 to the apoenzyme gave an EPR spectrum similar to that of the native enzyme, and the apoenzyme was fully reactivated by the optimal concentration of CuSO4 in less than 2 s.

Formation of microsomal cytochrome P-450 complexes studied by the NMR relaxation of water.

Cytochrome P-450 in microsomes from liver of phenobarbital treated and control rats has been studied by light absorption and by magnetic resonance methods (EPR and NMR). The nuclear relaxation rate of water protons was measured for microsomal suspensions in the presence of various reactants of Type I and II. The change of relaxation rates correlates well with the spin state conversion of the heme iron. No competition between eventual inner-sphere water molecules and the reactants seems to occur. The temperature dependence of the low spin to high spin equilibrium was studied by light absorption and was accounted for in the temperature variation of the molar relaxation rates of the two spin states.

Characterization of the iron-sulfur protein of the mitochondrial outer membrane partially purified from beef kidney cortex.

The iron-sulfur protein present in the mitochondrial outer membrane has been partially purified from beef kidney cortex mitochondria by means of selective solubilization followed by DEAE-cellulose chromatography. The EPR spectrum of the iron-sulfur protein with g-values at 2.01, 1.94 and 1.89 was well resolved up to 200 K which is unusual for an iron-sulfur protein. Analyses confirmed a center with two iron and two labile sulfur atoms in the protein. By measuring the effect of oxidation-reduction potential on the EPR signal amplitude, midpoint potentials at pH 7.2 were determined both for the purified iron-sulfur protein, +75 (+/- 5) mV, and in prepared mitochondrial outer membrane, +62 (+/- 6) mV. At pH 8.2 slightly lower values were indicated, +62 and 52 mV, respectively. The oxidation-reduction equilibrium involved a one electron transfer. A functional relationship to the rotenone-insensitive NADH-cytochrome c oxidoreductase in the mitochondrial outer membrane is suggested. Both this activity and the iron-sulfur center were sensitive to acidities slightly below pH 7 in contrast to the iron-sulfur centers of the inner membrane.

The mechanism of oxidation of reduced nicotinamide dinucleotide phosphate by submitochondrial particles from beef heart.

1. Oxidation of NADPH by various acceptors catalyzed by submitochondrial particles and a partially purified NADH dehydrogenase from beef heart was investigated. Submitochondrial particles devoid of nicotinamide nucleotide transhydrogenase activity catalyze an oxidation of NADPH by oxygen. The partially purified NADH dehydrogenase prepared from these particles catalyzes an oxidation of NADPH by acetylpyridine-NAD. In both cases the rates of oxidation are about two orders of magnitude lower than those obtained with NADH as electron donor. 2. The kinetic characteristics of the NADPH oxidase reaction and reduction of acetylpyridine-NAD by NADPH are similar with regard to pH dependences and affinities for NADPH, indicating that both reactions involve the same binding site for NADPH. The binding of NADPH to this site appears to be rate limiting for the overall reactions. 3. At redox equilibrium NADPH and NADH reduce FMN and iron-sulphur center 1 of NADH dehydrogenase to the same extents. The rate of reduction of FMN by NADPH is at least two orders of magnitude lower than with NADH. 4. It is concluded that NADPH is a substrate of NADH dehydrogenase and that the nicotinamide nucleotide is oxidized by submitochondrial particles via the NADH--binding site of the enzyme.

Evidence for two catalytically different binding sites of liver microsomal cytochrome P-450: importance for species and sex differences in oxidation pattern of lidocaine.

When the local anaesthetic drug lidocaine is added to liver microsomes biphasic type I spectral change titration curves can be observed. A high-affinity and a low-affinity phase is observed. In the present study we have found that microsomes from female rats have a dominant high-affinity phase, which can hardly be observed within microsomes from female guinea pigs. Male rats showed an intermediate phase. On incubation of lidocaine at concentrations of 1 micron or less with female rat liver microsomes a larger fraction of the drug was aromatically hydroxylated than deethylated. The opposite was true for guinea pig liver microsomes, and microsomes from male rats were intermediate. The ratio between the formation of deethylated and hydroxylated metabolites increased with the lidocaine concentration and at a lidocaine concentration of 10(-4)M deethylation was the dominant oxidation type in all microsomes. The data suggest that the two spectral phases represent two binding sites of cytochrome P-450 each having a certain "catalytic specificity" - the high affinity catalyzing aromatic hydroxylation and the "low-affinity site" deethylation. This hypothesis is further supported by the observed differential effects of pH and MgCl2 concentration on the two types of oxidation.