Parkin gene inactivation alters behaviour and dopamine neurotransmission in the mouse

Mutations of the parkin gene are the most frequent cause of early onset autosomal recessive parkinsonism (EO-AR). Here we show that inactivation of the parkin gene in mice results in motor and cognitive deficits, inhibition of amphetamine-induced dopamine release and inhibition of glutamate neurotransmission. The levels of dopamine are increased in the limbic brain areas of parkin mutant mice and there is a shift towards increased metabolism of dopamine by MAO. Although there was no evidence for a reduction of nigrostriatal dopamine neurons in the parkin mutant mice, the level of dopamine transporter protein was reduced in these animals, suggesting a decreased density of dopamine terminals, or adaptative changes in the nigrostriatal dopamine system. GSH levels were increased in the striatum and fetal mesencephalic neurons from parkin mutant mice, suggesting that a compensatory mechanism may protect dopamine neurons from neuronal death. These parkin mutant mice provide a valuable tool to better understand the preclinical deficits observed in patients with PD and to characterize the mechanisms leading to the degeneration of dopamine neurons that could provide new strategies for neuroprotection.     

Programmed death 1 is a marker of angioimmunoblastic T-cell lymphoma and B-cell small lymphocytic lymphoma/chronic lymphocytic leukemia

Programmed death 1 (PD-1) is a lymphoid receptor that negatively regulates immune responses. PD-1 expression was recently reported in some T-cell non-Hodgkin lymphoma (NHL) subtypes, but the expression profile of PD-1 and its ligands (PD-L1 and PD-L2) in B-NHLs remains largely to be characterized. To investigate this issue, monoclonal antibodies against PD-1, PD-L1, and PD-L2 were generated by immunization of balb-c mice. A series of 161 lymphoma tissue and 11 blood samples was analyzed using either immunohistochemistry or flow cytometry. In reactive lymph nodes, PD-1 was mainly expressed in follicular T cells. In B-NHLs, PD-1 was mainly expressed in reactive T cells; but expression was also noted in neoplastic B cells from small lymphocytic lymphoma (SLL, 12/13), grade III follicular lymphoma (3/3), and diffuse large cell lymphoma (2/25). In contrast, neoplastic B cells from mantle cell lymphoma (0/11), marginal zone lymphoma (0/12), Burkitt lymphoma (0/3), and grade 1 to 2 follicular lymphoma (0/40) were PD-1 negative. PD-L1 and PD-L2 were negative in small B-cell lymphomas, including B-SLL. Flow cytometry showed that blood cells from chronic lymphocytic leukemia (B-CLL) also displayed PD-1 expression, which could be increased by CD40 stimulation. PD-1 expression in T-NHLs was restricted to the angioimmunoblastic subtype (8/8). These results show that PD-1 expression among B-NHLs is mainly associated with SLL/CLL and is influenced by activation of the CD40/CD40L pathway. Because the anti-PD-1.6.4 antibody works on paraffin sections, it represents a useful tool to differentiate SLL/CLL from other small B-cell lymphomas.     

Effectiveness of Once-Weekly Rifapentine and Moxifloxacin Regimens against Mycobacterium tuberculosis in Mice

Mice infected with 1.6 x 10(7) CFU of Mycobacterium tuberculosis were treated 14 days later for 6 months with a regimen of once-weekly 10 mg of rifapentine and 75 mg of isoniazid per kg of body weight supplemented with either 150 mg of streptomycin per kg or 100 mg of moxifloxacin per kg during either both the 2-week daily initial and once-weekly continuation phases or only in the daily 2-week initial phase. On completion of treatment, all lung cultures were negative, except for three mice, each with a single colony: two whose rifapentine-isoniazid regimen was supplemented with streptomycin during the whole course of therapy and one whose rifapentine-isoniazid regimen had no initial daily phase, but was supplemented with streptomycin and moxifloxacin during the whole course of therapy. After 3 months of follow-up, positive lung cultures were obtained from 61 and 56% of mice supplemented with streptomycin during either the full course of therapy or only the daily 2-week initial phase, respectively, and 15 and 50% of mice supplemented with moxifloxacin during either the full course of therapy or only the daily 2-week initial phase, respectively. These results suggest that moxifloxacin has sterilizing activity against M. tuberculosis.     

Somatic mosaicism of the CAG repeat expansion in spinocerebellar ataxia type 3/Machado-Joseph disease

An expanded and unstable CAG repeat in the coding region of the MJD1 gene is the mutation responsible for spinocerebellar ataxia 3/Machado-Joseph disease. In order to determine whether there was a higher degree of instability in affected regions, the size of the expanded CAG repeat was analyzed in different regions of the central nervous system, in two unrelated SCA3/MJD patients. The degree of somatic mosaicism was quantified and compared to that in a SCA1 patient. Instability of the expanded CAG repeat was observed in peripheral tissues as well as in CNS of the three patients, but there was no correlation between the degree of mosaicism and the selective vulnerability of CNS structures. As in the other diseases caused by expanded CAG repeats, a lower degree of mosaicism was found in the cerebellar cortex of both SCA1 and SCA3/MJD patients, probably reflecting specific properties of this structure. In SCA3/MJD, the degree of mosaicism seemed to correlate with age at death rather than with the size of the expanded CAG repeat. Finally, somatic instability was more pronounced in SCA1 than in SCA3/MJD patients. Hum Mutat 11:23–27, 1998. © 1998 Wiley-Liss, Inc.     

The effect of relative humidity on CaCl2 nanoparticles studied by soft X-ray absorption spectroscopy

Ca- and Cl-containing nanoparticles are common in atmosphere, originating for example from desert dust and sea water. The properties and effects on atmospheric processes of these aerosol particles depend on the relative humidity (RH) as they are often both hygroscopic and deliquescent. We present here a study of surface structure of free-flying CaCl₂ nanoparticles (CaCl₂-NPs) in the 100 nm size regime prepared at different humidity levels (RH: 11–85%). We also created mixed nanoparticles by aerosolizing a solution of CaCl₂ and phenylalanine (Phe), which is a hydrophobic amino acid present in atmosphere. Information of hydration state of CaCl₂-NPs and production of mixed CaCl₂ + Phe nanoparticles was obtained using soft X-ray absorption spectroscopy (XAS) at Ca 2p, Cl 2p, C 1s, and O 1s edges. We also report Ca 2p and Cl 2p X-ray absorption spectra of an aqueous CaCl₂ solution. The O 1s X-ray absorption spectra measured from hydrated CaCl₂-NPs resemble liquid-like water spectrum, which is heavily influenced by the presence of ions. Core level spectra of Ca²⁺ and Cl⁻ ions do not show a clear dependence of % RH, indicating that the first coordination shell remains similar in all measured hydrated CaCl₂-NPs, but they differ from aqueous solution and solid CaCl₂.

Hydration state and surface composition of free-flying nanoparticles originating from aerosolized solutions of CaCl₂ and CaCl₂ and Phenylalanine are probed using X-ray absorption spectroscopy.     

Hypertransaminasemia in an adolescent]

CASE REPORT: An adolescent admitted to hospital because of an obvious convulsion seizure presented with a high level of serum macroaspartate aminotransferase. This macroaspartate aminotransferase was discovered by chance when blood tests were made. DISCUSSION: Macroaspartate aminotransferase is a persistent, benign phenomenon, probably not congenital, discovered either in healthy patients, or in adults suffering from malignancies or autoimmune diseases. Macroenzymes have been identified as a cause of benign increase in a number of serum enzymes, like macroamylase serum levels. The macroenzyme is often an immunoglobulin G-complexed enzyme. CONCLUSION: It is important for clinicians to be aware of their existence in order to avoid unnecessary procedures. It is important that the patient is informed of the macroaspartate aminotransferase and that the same is stated in his health record.     

Bactericidal Potencies of New Regimens Are Not Predictive of Their Sterilizing Potencies in a Murine Model of Tuberculosis

TMC207, rifapentine, and moxifloxacin are in clinical testing for the treatment of tuberculosis. Five experimental regimens with various combinations of TMC207, rifapentine, moxifloxacin, and pyrazinamide were tested for their bactericidal and sterilizing potencies in Swiss mice intravenously inoculated with Mycobacterium tuberculosis bacilli. TMC207 had the strongest bactericidal efficacy, while rifapentine was the strongest contributor to sterilizing efficacy. The rank order of sterilizing potencies was different from the rank order of bactericidal potencies, underlining the importance of prioritizing new regimens designed to shorten the treatment duration by their sterilizing potencies rather than by their bactericidal potencies. Both 3 months of treatment with a regimen combining TMC207, pyrazinamide, and rifapentine and 5 months of treatment with a regimen combining TMC207, pyrazinamide, and moxifloxacin resulted in relapse rates similar to the rate obtained by 6 months of treatment with rifampin-isoniazid-pyrazinamide.New drug regimens to improve the treatment and control of tuberculosis (TB) are critical components of any comprehensive strategy to address the current global TB epidemic. Current treatment regimens are inadequate, taking 6 to 9 months to treat drug-susceptible (DS) TB and as many as 30 months to treat multidrug-resistant (MDR) TB. In 1993, WHO declared tuberculosis a global emergency (21), and this reinitiated research into new drugs and tools in both commercial and noncommercial organizations. As a result of these efforts, the TB drug development pipeline is now in much better shape, with nine individual anti-TB drug candidates being clinically tested. A recent initiative (Critical Path to New TB Regimens [CPTR]) will stimulate development of combination regimens (combinations of new investigational drugs along with existing anti-TB drugs) to avoid stretching the development of a new regimen out over decades and to avoid developing each drug sequentially (18). Although there is no doubt that the CPTR approach will lead to improved efficiencies, limited financial resources, limited clinical trial capacities, and the urgency to help the patients in need all prevent testing all possible combinations in the clinic. It has therefore become crucially important to select the most promising combinations to be tested clinically from preclinical studies, which for practical reasons are so far limited to efficacy studies in mouse models of Mycobacterium tuberculosis infection.We tested five different regimens and compared them with the WHO regimen for DS TB: rifampin (RIF), isoniazid (INH), and pyrazinamide (PZA). Our goal was to rank order the bactericidal and sterilizing efficacies of both the individual drugs and the regimens. Bactericidal potency was evaluated after 2, 3, and 4 weeks of treatment. Sterilizing activity (also called stable cure) was evaluated by measuring relapse rates. Relapse is defined as the situation in which a mouse becomes culture negative while receiving anti-TB drugs but develops active TB 3 months after completion of treatment. A prerequisite to consider a new regimen of being able to shorten treatment duration with an acceptable success rate is that it leads to a relapse rate equivalent to that obtained with the standard 6-month DS TB regimen.TMC207 (TMC; formerly R207910), rifapentine (RFT), and moxifloxacin (MXF) are quite advanced in the anti-TB drug pipeline, and all three of them have been shown to be able to shorten the treatment duration in mouse models to some extent.TMC accelerates bactericidal activity in intravenously (i.v.) inoculated mice (1, 10), synergizes with PZA (7), and shortens the time needed to cure DS TB in mice from 6 to 4 months (9) and MDR TB to 6 months (8). Its potent bactericidal activity has recently been confirmed in patients with multidrug-resistant TB, in which it increased the proportion of sputum culture conversions from 9 to 48% after 2 months of treatment (4). RFT and MXF, when they were substituted for RIF and INH, accelerated bactericidal and sterilizing activities in the inhalation mouse model and shortened the time needed to prevent relapses from 6 to 3 months (15). The bactericidal and sterilizing efficacies of regimens including both TMC and RFT have so far not been studied in the mouse model.     

18FDG PET in vascular dementia: differentiation from Alzheimer's disease using voxel-based multivariate analysis.

The brain metabolic pattern of vascular dementia (VaD) remains poorly characterized. Univariate voxel-based analysis ignores the functional correlations among structures and may lack sensitivity and specificity. Here, we applied a novel voxel-based multivariate technique to a large ((18)F)2-fluoro-2-deoxy-D-glucose positron emission tomography data set. The sample consisted of 153 subjects, one-third each being probable subcortical VaD, probable Alzheimer disease (AD) (matched for Mini-Mental-State examination (MMSE) and age), and normal controls (NCs). We first applied principal component (PC) analysis and removed PCs significantly correlated to age. The remainders were used as feature vectors in a canonical variate analysis to generate canonical variates (CVs), that is, linear combinations of PC-scores. The first two CVs efficiently separated the groups. CV(1) separated VaD from AD with 100% accuracy, whereas CV(2) separated NC from demented subjects with 72% sensitivity and 96% specificity. Images depicting CV(1) and CV(2) showed that lower metabolism differentiating VaD from AD mainly concerned the deep gray nuclei, cerebellum, primary cortices, middle temporal gyrus, and anterior cingulate gyrus, whereas lower metabolism in AD versus VaD concerned mainly the hippocampal region and orbitofrontal, posterior cingulate, and posterior parietal cortices. The hypometabolic pattern common to VaD and AD mainly concerned the posterior parietal, precuneus, posterior cingulate, prefrontal, and anterior hippocampal regions, and linearly correlated with the MMSE. This study shows the potential of voxel-based multivariate methods to highlight independent functional networks in dementing diseases. By maximizing the separation between groups, this method extracted a metabolic pattern that efficiently differentiated VaD and AD.