Brain Structure and Degeneration Staging in Friedreich Ataxia: Magnetic Resonance Imaging Volumetrics from the ENIGMA-Ataxia Working Group

Objective

Friedreich ataxia (FRDA) is an inherited neurological disease defined by progressive movement incoordination. We undertook a comprehensive characterization of the spatial profile and progressive evolution of structural brain abnormalities in people with FRDA.

Methods

A coordinated international analysis of regional brain volume using magnetic resonance imaging data charted the whole‐brain profile, interindividual variability, and temporal staging of structural brain differences in 248 individuals with FRDA and 262 healthy controls.

Results

The brainstem, dentate nucleus region, and superior and inferior cerebellar peduncles showed the greatest reductions in volume relative to controls (Cohen d = 1.5–2.6). Cerebellar gray matter alterations were most pronounced in lobules I–VI (d = 0.8), whereas cerebral differences occurred most prominently in precentral gyri (d = 0.6) and corticospinal tracts (d = 1.4). Earlier onset age predicted less volume in the motor cerebellum (r_max = 0.35) and peduncles (r_max = 0.36). Disease duration and severity correlated with volume deficits in the dentate nucleus region, brainstem, and superior/inferior cerebellar peduncles (r_max = −0.49); subgrouping showed these to be robust and early features of FRDA, and strong candidates for further biomarker validation. Cerebral white matter abnormalities, particularly in corticospinal pathways, emerge as intermediate disease features. Cerebellar and cerebral gray matter loss, principally targeting motor and sensory systems, preferentially manifests later in the disease course.

Interpretation

FRDA is defined by an evolving spatial profile of neuroanatomical changes beyond primary pathology in the cerebellum and spinal cord, in line with its progressive clinical course. The design, interpretation, and generalization of research studies and clinical trials must consider neuroanatomical staging and associated interindividual variability in brain measures. ANN NEUROL 2021;90:570–583

Photo thermal effect graphene detector featuring 105 Gbit s-1 NRZ and 120 Gbit s-1 PAM4 direct detection

One of the main challenges of next generation optical communication is to increase the available bandwidth while reducing the size, cost and power consumption of photonic integrated circuits. Graphene has been recently proposed to be integrated with silicon photonics to meet these goals because of its high mobility, fast carrier dynamics and ultra-broadband optical properties. We focus on graphene photodetectors for high speed datacom and telecom applications based on the photo-thermo-electric effect, allowing for direct optical power to voltage conversion, zero dark current, and ultra-fast operation. We report on a chemical vapour deposition graphene photodetector based on the photo-thermoelectric effect, integrated on a silicon waveguide, providing frequency response >65 GHz and optimized to be interfaced to a 50 Ω voltage amplifier for direct voltage amplification. We demonstrate a system test leading to direct detection of 105 Gbit s^-1 non-return to zero and 120 Gbit s^-1 4-level pulse amplitude modulation optical signals.

Sensitivity of Neuroimaging Indicators in Monitoring the Effects of Interferon Gamma Treatment in Friedreich's Ataxia

The identification of efficient markers of disease progression and response to possibly effective treatments is a key priority for slowly progressive, rare and neurodegenerative diseases, such as Friedreich’s ataxia. Various imaging modalities have documented specific abnormalities in Friedreich’s ataxia that could be tracked to provide useful indicators of efficacy in clinical trials. Advanced MRI imaging (diffusion tensor imaging, DTI; functional MRI, fMRI; and resting-state fMRI, rs-fMRI) and retinal imaging (optical coherence tomography, OCT) were tested longitudinally in a small group of Friedreich’s ataxia patients participating in an open-label clinical trial testing the safety and the efficacy of 6-month treatment with interferon gamma. While the DTI indices documented the slow progression of fractional anisotropy loss, fMRI and rs-fMRI were significantly modified during and after treatment. The fMRI changes significantly correlated with the Scale for the Assessment and Rating of Ataxia, which is used to monitor clinical response. OCT documented the known thickness reduction of the retinal nerve fiber layer thickness, but there was no change over time. This pilot study provides indications for the potential utility of fMRI and rs-fMRI as ancillary measures in clinical trials for Friedreich’s ataxia.

Manipulation and generation of supercurrent in out-of-equilibrium Josephson tunnel nanojunctions

We demonstrate experimentally the manipulation of supercurrent in Al-AlOx-Ti Josephson tunnel junctions by injecting quasiparticles in a Ti island from two additional tunnel-coupled Al superconducting reservoirs. Both supercurrent enhancement and quenching with respect to equilibrium are achieved. We demonstrate cooling of the Ti line by quasiparticle injection from the normal state deep into the superconducting phase. A model based on heat transport and the nonmonotonic current-voltage characteristic of a Josephson junction satisfactorily accounts for our findings.

Mycophenolate Mofetil Pharmacokinetic Monitoring in Pediatric Kidney Transplant Recipients

This open-label, longitudinal, long-term study of de novo pediatric renal transplant recipients was designed to investigate the pharmacokinetics (PK) of mycophenolic acid (MPA) and its possible interaction with cyclosporine (CsA). Thirty-four children on an immunosuppressive regimen of CsA, prednisone, and mycophenolate mofetil (MMF, 300-400 mg/m2 twice daily) were investigated at 6, 30, 180, and 360 days after transplantation. Considerable interindividual variability in the areas under the concentration curve (AUC(0-12)) of MPA was observed during the follow-up, although the dose of MMF remained the same over the same time. Predose levels (C0) increased significantly during the first 6 months after transplantation: C0 at 6 and 180 days after transplantation was 0.8 +/- 0.6 and 1.9 +/- 1.1 microg/mL (P < .0001). A significant time-dependent increase in the AUC of MPA was also observed during the first 6 posttransplant months: AUC(0-12) at 6 and 180 days after transplantation was 23.3 +/- 10.8 and 40 +/- 11.6 mg*h/L (P = .003). MPA concentrations 3 and 4 hours after MMF intake were the individual time points that best correlated with the full MPA AUC (r = 0.8 and 0.79; P < .001). The abbreviated MPA AUC (0-4 hours) correlated reasonably with the full AUC (r = 0.87; P < .001). Finally, a significant reduction in CsA dose during the first 6 posttransplant months (P < .001) matched the significant increases in both MPA C0 and full MPA AUC, thus demonstrating the interaction of the 2 immunosuppressive drugs. These observations suggest the need for therapeutic drug monitoring when adjusting the dose of MMF in children.

Cyclosporine monitoring in stable, long-term, pediatric kidney transplant recipients: the value of C2 determination

Although a generalized consensus has been reached for therapeutic drug monitoring of cyclosporine microemulsion in adult transplant patients, clear guidelines are recently not available for the pediatric population. In this retrospective analysis of pharmacokinetic data obtained from stable, long-term, pediatric kidney transplant recipients, we sought to define a possible approach to manage cyclosporine therapy in a pediatric setting. The 2-hour postdose cyclosporine blood concentration, C(2), rather than trough levels, was the best single time point predictor of the area under the concentration curve. We concluded that therapeutic drug monitoring of cyclosporine-based immunosuppressive regimens should be tailored based on C(2) determinations for pediatric kidney transplant recipients.

The captopril test in children with renovascular and renal hypertension

We used the captopril test (CT) in 32 children, 8 with renovascular hypertension (RVH), 17 with renal hypertension (RH) and 7 with normal blood pressure, in order to study the renin-angiotensin system activation (RASA). All children affected by RVH presented a positive CT: a post-captopril plasma renin activity (PRA) of 12 ng ml-1 h-1 or more, an absolute PRA increase of 10 ng ml-1 h-1 or more and a 150% increase or more, or 400% or more if the baseline PRA was less than 3 ng ml-1 h-1. The CT may be useful for demonstrating the RASA in RVH.

B7-1 amplifies the response to interleukin-2-secreting tumor vaccines in vivo, but fails to induce a response by naive cells in vitro

Parental and interleukin-2 (IL-2)-secreting CMS5 tumor cells were transfected with the B7-1 costimulatory molecule to amplify anti-tumor responses. CMS5 cells transfected with B7-1 grew more slowly in vivo than did parental CMS5 cells. Moreover, tumor cells secreting levels of IL-2 too low to cause rejection alone were rejected following transfection with B7-1. To determine whether the expression of B7-1 enabled the tumor cells to activate T cells directly, their ability to stimulate in vitro functional responses by T cells was examined. We found that neither B7-1+ nor IL-2-secreting, B7-1+ CMS5 cells stimulated naive spleen cells to proliferate or to become cytotoxic. In contrast, restimulation of primed T cells by B7-1+ CMS5 cells resulted in stronger cytotoxicity responses than seen following restimulation by parental CMS5 cells. Lysis was even higher if the B7-1+ tumor cells also secreted IL-2. Our results suggest that the expression of costimulatory molecules can augment responses generated by vaccinating with IL-2-secreting tumor cells. Furthermore, they are consistent with the hypothesis that the initiation of an anti-tumor response by naive T cells may depend upon initial antigen presentation by another unidentified cell and that the major action of IL-2-secreting and/or B7-1+ tumor cell vaccines might be to potentiate the response of already primed cells.

Influence of spermatozoa characteristics on gamete intra-fallopian transfer procedures: analysis of results obtained utilizing normozoospermic, oligoasthenozoospermic and donor spermatozoa

The objective of this study was to analyze the efficacy of the gamete intra-Fallopian transfer (GIFT) procedure in relation to spermatozoa characteristics. A total of 268 infertile couples enlisted for GIFT were categorized into three groups on the basis of semen characteristics in the husband. These included oligoasthenozoospermic men in 88 retrieval cycles (group 1), normozoospermic men in 116 cycles (group 2) and azoospermic partners who needed donor semen in 86 cycles (group 3). All female patients had ovarian stimulation and laparoscopic GIFT. Pregnancy rates were significantly higher with donor spermatozoa than with oligoasthenozoospermic or normozoospermic spermatozoa, i.e. 51.1% versus 15.9% (P < 0.001), and 32.7% (P < 0.005). Implantation rates were significantly higher with donor spermatozoa than with normo- or oligoasthenozoospermic spermatozoa (P < 0.01). These data suggest that GIFT does not give good results with male factor infertility. Donor cryopreserved semen gives higher pregnancy and implantation rates than normozoospermic semen, and GIFT with donor spermatozoa gives a good chance of pregnancy to couples previously treated with artificial insemination using donor semen.

[Frequency of microalbuminuria in an adult population]

Urinary samples overnight collected from the thousand normotensive adults with normal urinalysis and normal serum levels of creatinine, urea and glucose were tested for the presence of microalbuminuria by latex test Sclavo. Fourty-five cases were positive: the values of microalbuminuria in 21 of these cases tested with RIA method exceeded 26 mg/l; one hundred twenty-six latex-negative cases evidenced lower RIA values. The high sensitivity of the test and its clinical significance suggest the need of an automatic procedure for detecting microalbuminuria in Albustix-negative urine samples.

A comparison of the delta copper T and the copper T 200 in Bologna, Italy

An analysis is presented of a comparative study of the Delta T and Copper T 200 IUDs. A total of 195 postabortion insertions was performed between March 1981 and August 1982. All insertions were performed with an inserter. Primary bleeding/pain complaints after insertion were largely related to intermenstrual problems, with spotting the most frequently reported. Nine women had their devices removed for PID. One pregnancy occurred at ten months in the Delta T group. Both groups had one expulsion/displacement. Eight devices in each group were removed for bleeding/pain. Two women in the TCu group had their devices removed for personal reasons. The 6-months continuation rates for the two groups were 85.5 for the Delta T group and 82.2 for the TCu group. The 6-months follow-up rate for the Delta T group was 39.4 and 38.8 for the TCu group.

Neurochemical effects of minaprine, a novel psychotropic drug, on the central cholinergic system of the rat

Minaprine, a novel psychotropic drug with antidepressant, anticataleptic and antiaggressive properties, produced an increase in rat brain regional acetylcholine content at a subconvulsant dose of 30 mg/kg IP. The greatest increase (60%) was produced in the striatum, whereas an increase of about 35% was obtained in the hippocampus and the rest of the cortex. A small but significant increase of 14% was also found in the midbrain-hindbrain region. Minaprine decreased choline content only in the striatum. No tolerance to acute challenge was observed after 10-day chronic treatment. In vitro, the drug had no effect on striatal choline acetyltransferase activity up to a concentration of 160 microM and only weakly displaced (3H) dexetimide from its specific muscarinic receptor binding sites in striatum (IC50, 2 X 10(-4) M). After in vivo administration the drug did not affect sodium-dependent high affinity choline uptake by a hippocampal homogenate. On the other hand, the drug inhibited both striatal and hippocampal acetylcholinesterase activity at high (40-160 microM) concentrations in vitro. In vivo the drug produced a brief (5 min), small (18%) decrease in the enzymic activity which corresponded in time to the peak drug level attained in the brain, but was not concomitant with a change in striatal acetylcholine content. By contrast, the increase in striatal acetylcholine appeared after 30 min when there was no longer inhibition of acetylcholinesterase activity and when the level of minaprine in brain was reduced by 78%. Blockade of dopamine receptors by pimozide pretreatment partially prevented the increase in striatal acetylcholine produced by minaprine, whereas interference with cholinergic or serontonergic neurotransmission was without effect.(ABSTRACT TRUNCATED AT 250 WORDS)