Molecular analyses of the LRRK2 gene in European and North African autosomal dominant Parkinson's disease

BACKGROUND

Mutations in the leucine-rich-repeat kinase 2 (LRRK2) gene have been identified in families with autosomal dominant Parkinson's disease (ADPD), the most common of which is the p.G2019S substitution that has been found at varying frequencies worldwide. Because of the size of the LRRK2 gene, few studies have analysed the entire gene in large series of ADPD families.

METHODS

We performed extensive mutation analyses of all 51 coding exons of the LRRK2 gene in index cases from 226 Parkinson's disease families compatible with autosomal dominant inheritance, mostly from France (n = 182) and North Africa (n = 14).

RESULTS

We found 79 sequence variants, 29 of which were novel. Eight potentially or proven pathogenic mutations were found in 22 probands (9.7%). There were four novel amino acid substitutions that are potentially pathogenic (p.S52F, p.N363S, p.I810V, p.R1325Q) and two novel variants, p.H1216R and p.T1410M, that are probably not causative. The common p.G2019S mutation was identified in 13 probands (5.8%) including six from North Africa (43%). The known heterozygous p.R1441H and p.I1371V mutations were found in two probands each, and the p.E334K variant was identified in one single patient. Most potentially or proven pathogenic mutations were located in the functional domains of the Lrrk2 protein.

CONCLUSION

This study leads us to conclude that LRRK2 mutations are a common cause of autosomal dominant Parkinson's disease in Europe and North Africa.

A multidisciplinary study of patients with early-onset PD with and without parkin mutations

OBJECTIVE

To establish phenotype-genotype correlations in early-onset Parkinson disease (EOPD), we performed neurologic, neuropsychological, and psychiatric evaluations in a series of patients with and without parkin mutations.

BACKGROUND

Parkin (PARK2) gene mutations are the major cause of autosomal recessive parkinsonism. The usual clinical features are early-onset typical PD with a slow clinical course, an excellent response to low doses of levodopa, frequent treatment-induced dyskinesias, and the absence of dementia.

METHODS

A total of 44 patients with EOPD (21 with and 23 without parkin mutations) and 9 unaffected single heterozygous carriers of parkin mutations underwent extensive clinical, neuropsychological, and psychiatric examinations.

RESULTS

The neurologic, neuropsychological, and psychiatric features were similar in all patients, except for significantly lower daily doses of dopaminergic treatment and greater delay in the development of levodopa-related fluctuations (p < 0.05) in parkin mutation carriers compared to noncarriers. There was no major difference between the two groups in terms of general cognitive efficiency. Psychiatric manifestations (depression) were more frequent in patients than in healthy single heterozygous parkin carriers but did not differ between the two groups of patients.

CONCLUSION

Carriers of parkin mutations are clinically indistinguishable from other patients with young-onset Parkinson disease (PD) on an individual basis. Severe generalized loss of dopaminergic neurons in the substantia nigra pars compacta in these patients is associated with an excellent response to low doses of dopa-equivalent and delayed fluctuations, but cognitive impairment and special behavioral or psychiatric symptoms were not more severe than in other patients with early-onset PD.

Rare heterozygous parkin variants in French early-onset Parkinson disease patients and controls

BACKGROUND

Mutations in the parkin gene cause autosomal recessive early-onset parkinsonism. The effect of single heterozygous mutations in parkin is still unclear. The aim of this study was to evaluate the frequency of exonic parkin variants in a case-control study.

METHODS

The parkin gene was screened for both point mutations and exon rearrangements in 172 French patients with Parkinson disease (PD) and 170 controls from the same population. Patients with single parkin variants were also screened for PINK1, DJ-1 and LRRK2 exon 41 mutations.

RESULTS

10 exonic sequence variations were identified, including 3 known polymorphisms and 7 rare heterozygous variants, 2 of which were novel. There were significantly more rare heterozygous variants in patients (n = 10) with early-onset PD than in controls (n = 2). Screening of PINK1, DJ-1 and LRRK2 exon 41 in the 10 patients heterozygous for parkin failed to identify a second causative mutation.

CONCLUSION

These results suggest that single parkin mutations increase the risk of early-onset PD, but the possibility of a second parkin mutation cannot be excluded.

Causal relation between alpha-synuclein gene duplication and familial Parkinson's disease

The alpha-synuclein gene (SNCA) has been implicated in autosomal dominant forms of Parkinson's disease. We screened 119 individuals from families with this rare form of the disease for SNCA duplications by semiquantitative multiplex PCR. Two patients had duplications, which were confirmed by analysis of intragenic and flanking microsatellite markers. The phenotype in both patients was indistinguishable from idiopathic Parkinson's disease and no atypical features were present, by contrast with reports of families with triplication of the same gene. These results indicate that SNCA is more frequently associated with familial Parkinson's disease than previously thought, and that there is a clear dosage effect according to the number of supernumerary copies of this gene.

Screening for DJ-1 mutations in early onset autosomal recessive parkinsonism

The DJ-1 gene was identified as responsible for early onset autosomal recessive parkinsonism in two families (PARK7). In this study, after excluding mutations in the parkin gene, the authors screened a large series of early onset autosomal recessive parkinsonism families and consanguineous isolated patients of diverse geographic origins for DJ-1 mutations. No mutations were found. This indicates that PARK7 is not a common locus for early onset autosomal recessive parkinsonism, and that one or more new loci remains to be identified.

New parkin mutations and atypical phenotypes in families with autosomal recessive parkinsonism

The frequency of parkin mutations was evaluated in 30 families of highly diverse geographic origin with early-onset autosomal recessive parkinsonism. Twelve different mutations, six of which were new, were found in 10 families from Europe and Brazil. Patients with parkin mutations had significantly longer disease duration than patients without the mutation but with similar severity of disease, suggesting a slower disease course. Two patients with parkin mutations had atypical clinical presentation at onset, with predominant tremor when standing.

Implications of the introduction of fixed reimbursement rates in Germany

The introduction of fixed reimbursement rates in Germany for cardiac surgery of adults, mainly coronary artery bypass grafting (CABG) and valve surgery, has shifted the financial risk from insurers to providers of medical care, namely hospitals. Costs in turn are closely related to the preoperative condition of a patient, implicating that surgery in high-risk patients may result in financial losses for the operating institution. Furthermore, reports from the Society of Thoracic Surgeons national database indicate a trend over time towards a higher proportion of patients with adverse risk factors for the United States. To determine whether these trends are holding true for Germany, we conducted an analysis of the data from two institutions with the following questions: 1. Is there a trend over time towards unfavourable risk factors, and 2. Is there a relation between preoperative risk factors and postoperative length of stay? From 1987 to 1995, 3872 patients underwent CABG at the Departments of Cardiovascular Surgery of Justus-Liebig University Giessen and German Heart Center Munich. Medical history, preoperative condition, intra-, and postoperative course were recorded for these patients according to the protocol of the German quality assurance program. Preoperative condition of the patient was summarized with an additive risk score. The correlation between postoperative length of stay in the intensive care unit (ICU) and preoperative risk was investigated. For a subgroup of 30 patients, detailed cost analysis was performed and the relationship to preoperative risk examined. For all risk factors examined, a significant increase in prevalence between 1987 and 1995 was observed. A close correlation between preoperative risk and postoperative length of stay in the ICU was found. A similar correlation existed between preoperative risk and actual costs of treatment. In addition, high-risk patients had a significantly higher likelihood of being discharged directly from our ICU to the ICU of other hospitals. Postoperatively, high-risk patients suffer more often from morbidity with subsequent prolonged intensive care and are, therefore, a financial burden for the operating institution in a reimbursement system with fixed rates. This is aggravated by the fact that a trend towards adverse risk profiles among patients undergoing cardiac surgery can be observed. Both factors combined may result in a scenario where those who would benefit most are denied surgical treatment.

Sequence of the new Drosophila melanogaster small heat-shock-related gene, lethal(2) essential for life [l(2)efl], at locus 59F4,5

In this study, we report the molecular cloning of a novel Drosophila melanogaster small heat-shock (HS)-homologous gene, l(2)efl, identified on the right arm of the second chromosome at locus 59F4,5. We describe the temporal expression of l(2)efl in the wild-type and present its structure. The deduced amino-acid sequence of the Efl protein shows significant homology to all known small HS proteins identified in Drosophila and vertebrates, and to mammalian alpha-crystallin.

Ecogenetic and pharmacogenetic studies in Hungary

12 population groups of Hungary, 1514 individuals altogether, have been studied for polymorphisms of alpha 1antitrypsin, serum cholinesterase, paraoxonase and delta-aminolevulinic acid dehydrase, N-acetyltransferase variation and aldehyde dehydrogenase deficiency. A possible relationship between their allele frequencies and environmental factors in the context of ecogenetic and pharmacogenetic phenomena in Hungary is discussed.

Factors determining ventricular fibrillation after induced cardiac arrest

Ventricular fibrillation following release of the aortic cross clamp is not uncommon. In 38 patients undergoing aortic valve replacement we investigated if this disturbance of rhythm is due to perioperative myocardial ischemia or due to deterioration of myocardial function prior to surgery. In all cases hypothermic cardioplegic arrest (Bretschneider) was used. The mean duration of ischemia was 49.39 +/- 10.46 minutes. After release of the aortic cross clamp in 17 of 38 patients ventricular fibrillation occurred. To find out which factors are responsible for the occurrence of ventricular fibrillation we performed a statistical analysis. Thereby we found out that the occurrence of ventricular fibrillation did not correlate with ischemia, the maximal level of myocardium-bound creatine kinase, the NYHA stage, or the left ventricular end diastolic pressure. The left-ventricular concentration of noradrenaline determined just before release of the aortic cross clamp showed a significant negative correlation with the occurrence of ventricular fibrillation. From our results we conclude that ischemic injury was not the determining factor for the occurrence of ventricular fibrillation in our study. We suggest that the significant correlation with reduced myocardial noradrenaline content demonstrates that myocardial deterioration prior to surgery is the determining factor for the occurrence of ventricular fibrillation.

[Pharmacokinetic parameters as criteria for clinical use of hydroxyethyl starch preparations]

Pharmacokinetic Parameters as Criteria for Clinical Use of Hydroxyethyl Starch Preparations In a study with volunteers (n = 2 x 6) pharmacokinetic data of two only marginally differing starch preparations were investigated. We were able to demonstrate that there exist significant differences in raw materials used which determined the pharmacokinetic data in humans. Newly implemented analyzing methods (LALLS) were used. In addition to the degree of substitution, further differences concerning the position of hydroxyethylization at the anhydroglucose molecule could be documented. The C2/C6 positions of hydroxyethylization at the molecule seem to be most essential. To classify and to differentiate starch preparations we propose to include these data in general informations for clinicians because these differences might determine clinical usage and efficacy.

Beneficial effects of prostacyclin in a rabbit endotoxin shock model

Thirty rabbits received an infusion of lipopolysaccharide B (75 micrograms/kg.h) over 4 hours (groups E, EI, EA; n = 10 each). Saline was given to a control group (C; n = 8). In group EI, prostacyclin (PGI2; 500 ng/kg.min) was given simultaneously to endotoxin. Into group EA animals, aspirin (20 mg/kg) was injected before the endotoxin infusion was started. PGI2 and aspirin both improved survival of animals (6/10 each vs. 2/10 in group E). The drop of platelet counts was significantly reduced by PGI2, while leukocyte depletion was similar in all endotoxin groups. PGI2 preserved the functional capacity of platelets as indicated by collagen stimulated aggregation and thromboxane formation. PGI2 but not aspirin significantly reduced renal fibrin deposition.

[Effect of particle size and emulsifier on pharmacokinetic values of a parenterally administered fat emulsion]

To evaluate pharmacokinetic data during parenteral application of a fat emulsion a controlled study in healthy volunteers was performed. Another aim of the study was to investigate whether these kinetics could be changed by modification of the emulsion. For this purpose, 10 male medical students--free of any metabolic disorders--received modified batches of one fat emulsion (Lipovenös), differing with respect to particle size or emulsifier. The emulsions were applied using a pump-controlled continuous infusion technique. The dosage was calculated according to body weight: 0.1 g/kg B.W./h. There was a 7-10 day interval between one application and the following study period, again using the same volunteers. Thus every volunteer served as his own control. Routine laboratory parameters as well as parameters relating to fat metabolism were measured. While routine laboratory parameters were not statistically different between the groups, pharmacokinetic data showed differences according to the batches used. Highest triglyceride and free fatty acid levels i.s. were present after application of the emulsion with low medium particle size, while lowest levels were found after increasing the particle size to 380 nm. In addition, it could be documented that an increase in medium particle size resulted in higher elimination rate, transfer and pool size. The modified emulsifier led to an additional increase of these effects, thus inducing beneficial metabolic profiles. The results of the present investigation might perhaps enable us to adjust the profile of future fat emulsions, with the aim of optimizing or restoring metabolic hemostasis.

Über den parenteralen Einsatz einer Fettemulsion in der frühen postoperativen Phase

In einer randomisierten prospektiven Studie wurde an 30 Patienten in der postoperativen Phase der alternative Einsatz eines Kohlenhydrat-regimes (= Kontrollgruppe) im Vergleich mit einem teilweisen Ersatz der Kohlenhydratkalorien durch eine Fettemulsion (= Fett-Kohlenhydrat-Regime) getestet. Neben den üblichen Routine-Laborparametern wurde mittels Stickstoffbilanz und Analyse der kurzlebigen Proteine sowie verschiedener Meβparameter des Fettstoffwechsels überprüft, mit welchen metabolischen Konsequenzen, sowohl im Bereich des Proteinstoffwechsels als auch im Bereich des Fettstoffwechsels, bei den genannten Regimen zu rechnen ist. Die drei verwendeten Ernährungsregime führten zu weitgehend vergleichbaren metabolischen Ergebnissen, wobei unter hoher Fettdosierung (3 g/kg KG/Tag) ein nicht signifikanter Anstieg der Triglyzeridspiegel über die Vergleichswerte der Kontrollgruppe registriert wurde. Von seiten der Stickstoffbilanz sowie von seiten der weiteren Parameter des Proteinstoffwechsels erwies sich das Regime mit 1,5 g Fett/kg KG/Tag als das günstigste. Gravierende Dysregulationen im Bereich des postoperativen Stoffwechsels konnten nicht registriert werden, die verwendete Fettemulsion erwies sich auch in bezug auf die pulmonale Funktion der untersuchten Patienten als günstig. In Kombination mit Kohlenhydraten und Aminosäuren bietet das Kohlenhydrat-Fett-Regime offensichtlich bessere postoperative metabolische Profile, von denen besonders Patienten mit reduziertem Ernährungszustand und verminderter respiratorischer Reserve profitieren können.

Über den Einfluß von Teilchengröße und Emulgator auf pharmakokinetische Kenndaten einer parenteral applizierten Fettemulsion

In einer kontrollierten Studie sollte untersucht werden, wie pharmakokinetische Kenndaten einer Fettemulsion durch Modifikation beeinflußt werden können. Zu diesem Zweck erhielten 10 männliche Probanden die jeweils modifizierten Chargen in 7–10tägigem Abstand infundiert. Nach einer 10–12stündigen Nahrungskarenz und Blutentnahme zur Leerwertbestimmung wurden die Emulsionschargen kontinuierlich in gewichtsbezogener Dosierung von 0,1 g/kg KG/h appliziert. Zu insgesamt 13 Meßzeitpunkten erfolgten weitere Blutentnahmen zur Bestimmung sog. physiologischer Referenzgrößen mit besonderer Berücksichtigung des Fettstoffwechsels und der Gerinnung. Die Ergebnisse zeigen, daß sowohl Modifikation der Teilchengröße als auch der Emulgatorzusammensetzung (Eilezithin) insbesondere die Eliminations- bzw. Transfer- und Poolwerte der Triglyzeride/freien Fettsäuren beeinflussen. Dabei erwies sich die Emulsion mit der größten mittleren Teilchengröße (x: 380 nm) und verändertem Emulgator als am günstigsten. Dies betraf sowohl die pharmakokinetischen Daten als auch die allgemeine Stoffwechselsituation. Inwieweit diese günstigen Stoffwechselprofile mit einer entsprechenden Oxidation einhergehen, muß in weiteren Untersuchungen geklärt werden. Dennoch lassen sich aus den Ergebnissen grundlegende Konsequenzen für die Entwicklung von Fettemulsionen bzw. das durch sie induzierte Stoffwechselgeschehen ableiten.

[Calcium antagonists in anesthesia. Additive analgesia using nimodipine in heart surgery]

Stress and pain induced by surgical trauma seem to be attenuated when calcium antagonists have been applied. In order to ascertain the effect of nimodipine, a new strong acting calcium channel blocker on plasma levels of various stress hormones twenty patients undergoing cardiovascular surgery where investigated in two groups. Ten patients received high-dose fentanyl anaesthesia (mean: 2,45 mg fentanyl/patient), whereas another ten patients were treated with 0,1 mg fentanyl/patient in addition to nimodipine 1,0 micrograms/kgbw X min (from onset of anaesthesia until start of extracorporeal circulation). Between the two groups were no significant differences with respect to perioperative course and postoperative demand for analgetics. Plasma levels of ACTH, somatotropin, glucose and free glycerol were markedly elevated in all patients (n = 20) intra- and postoperatively, whereas cortisol and prolactin remained unchanged. The present data suggest an additive analgesic effect of nimodipine during surgery. This phenomenon is possibly due to a blocking effect of calcium channel blockers on nociceptive nerves. The present model assumes that calcium is essential in pain perception and that decreased calcium would result in analgesia.

Estimation of T- and K-cell activity in the peripheral blood of sarcoidosis patients

Depressed ADCC activity was found in sarcoidosis patients in clinical Stage II when whole blood was used as the effector cell pool. Whole blood in Stage I patients as well as purified peripheral lymphocytes of sarcoidosis patients did not reveal a diminished cytotoxic activity. Stimulation experiments with PHA, Con A, and PPD in two different concentrations resulted in a normal PHA response, a significantly decreased Con A response (regardless of the clinical stage of the patients), and a significantly decreased PPD responsiveness of peripheral lymphocytes in Stage II patients, respectively. Regarding the distribution of peripheral B and T lymphocytes, only a significantly depressed T-cell number in Stage I sarcoidosis patients was observed. Peripheral cells forming EA and EAC rosettes and staining for membrane-bound immunoglobulins were within normal ranges. Serum antibody titers to different herpes viruses, including Epstein-Barr virus, were found not to be elevated. Twenty percent of sarcoidosis patients showed anti-immunoglobulins in their sera specific for the Fc and Fab fragment.

Antibody-dependent cellular cytotoxicity and B-and T-cell activity in the peripheral blood of myasthenia gravis patients

Antibody-dependent cellular cytotoxicity (ADCC) was found to be significantly decreased in whole blood as well as in purified lymphocyte preparations from myasthenia gravis patients. Decreased ADCC was found not to correlate with the clinical classification nor with the therapy regimen, including immunosuppressive agents. PHA, Con A, and PPD responsiveness of peripheral blood lymphocytes was normal. Likewise no significant decrease was observed in the T-and B-cell distribution in the peripheral blood.

[Results of the synchronization therapy with vincristine and cyclophosphamide in lymphogranulomatosis, reticulum cell sarcoma and lymphosarcoma. A phase II study (author's transl)]

The effectiveness of synchronization therapy was tested on 88 patients who had already undergone some form of treatment for lymphogranulomatosis (stage III B and IV), generalized reticulum cell sarcoma or lymphosarcoma. This therapeutical concept is based on a partial synchronic increase in tumor cells induced by noncytocidal doses of vincristine, followed by cytostatic or cytocidal treatment with cyclophosphamide during DNA synthesis of the partially synchronized tumor cells. The therapeutic plan is similar to a single-agent therapy. In lymphogranulomatosis, complete remission could be achieved in 14 out of 19 cases (stage III B) and in 9 out of 24 cases (stage IV). The mean remission period during an orally administered cytostatic maintenance therapy was 15 1/2 months. The highest rate of remission was found in the mixed cell type of granulomas (23 out of 24 patients). In the non-Hodgkin's lymphomas, complete remission was achieved in 13 out of 30 cases (lymphosarcoma) and in 19 out of 15 cases (reticulum cell sarcoma). The mean remission period for orally administered cytostatic maintenance therapy was 16 months for lymphosarcoma and 11 1/2 months for reticulum cell sarcoma. These therapeutic results are comparable to those achieved by very effective schemes of combination chemotherapy but the toxic side-effects of synchronization therapy are considerably lower.