Molecular Epidemiology in 591 Italian Probands With Nonsyndromic Retinitis Pigmentosa and Usher Syndrome

PurposeTo describe the molecular epidemiology of nonsyndromic retinitis pigmentosa (RP) and Usher syndrome (US) in Italian patients.MethodsA total of 591 probands (315 with family history and 276 sporadics) were analyzed. For 155 of them, we performed a family segregation study, considering a total of 382 relatives. Probands were analyzed by a customized multigene panel approach. Sanger sequencing was used to validate all genetic variants and to perform family segregation studies. Copy number variants of selected genes were analyzed by multiplex ligation-dependent probe amplification. Four patients who tested negative to targeted next-generation sequencing analysis underwent clinical exome sequencing.ResultsThe mean diagnostic yield of molecular testing among patients with a family history of retinal disorders was 55.2% while the diagnostic yield including sporadic cases was 37.4%. We found 468 potentially pathogenic variants, 147 of which were unpublished, in 308 probands and 66 relatives. Mean ages of onset of the different classes of RP were autosomal dominant RP, 19.3 ± 12.6 years; autosomal recessive RP, 23.2 ± 16.6 years; X-linked RP, 13.9 ± 9.9 years; and Usher syndrome, 18.9 ± 9.5 years. We reported potential new genotype-phenotype correlations in three probands, two revealed by TruSight One testing. All three probands showed isolated RP caused by biallelic variants in genes usually associated with syndromes such as PERCHING and Senior-Loken or with retinal dystrophy, iris coloboma, and comedogenic acne syndrome.ConclusionsThis is the largest molecular study of Italian patients with RP in the literature, thus reflecting the epidemiology of the disease in Italy with reasonable accuracy.     

Detection of antibodies to human immunodeficiency virus type 2 (HIV-2) in blood donor sera using United States assay methods for anti-HIV type 1

Twelve serum samples from French blood donors that were uniformly reactive in tests for antibody to human immunodeficiency virus type 2 (anti-HIV-2) also were reactive in 92 to 100 percent of tests with three anti-HIV type 1 (anti-HIV-1) enzyme-linked immunoassays currently in widespread use for donor screening in the United States. Supplemental tests for anti-HIV-1 on these anti-HIV-2-reactive samples differed in their responses. All samples reacted in a licensed anti-HIV-1 Western blot, but there was an atypical band near the p41 position, which could be a clue to the fact that this result was a cross-reaction with anti-HIV-2. A recombinant immunoblot gave an indeterminate result for anti-HIV-1 in all 12 samples. A local immunofluorescence assay for anti-HIV-1 reacted with 92 percent of the samples, but a commercial one detected only 58 percent.     

Anti-Endothelial Autoantibodies in Patients With Sudden Hearing Loss

Objectives/Hypothesis: Sudden hearing loss (HL) can be caused by autoimmune disorders localized to the inner ear or secondary to systemic immune diseases. Studies in autoimmune animal strains showing HL have reported changes in the cochlear stria vascularis. The authors investigated the presence of antiendothelial cell antibodies (AECA) to see if immunemediated vasculitis may play a role in human sudden HL. Study Design: A prospective study in patients with sudden HL. Methods: Fifteen consecutive patients (mean age, 32 y) affected by sudden HL and 14 normal subjects were included. Patients with familial deafness and metabolic diseases were excluded. Extensive audiovestibular, imaging, microbiological, immunological, and routine examinations were performed. AECA were detected on rat kidney tissue sections on the sera collected at ?20°C. Results: AECA were positive in 8 of 15 patients (53%) (2 of 5 men and 6 of 10 women), thus differing significantly from the normal control population, in which only 2 of 14 tested AECA positive (P = .023). Conclusions: In patients with sudden HL, immune-mediated vascular damage can have a pathogenetic role and AECA might represent a serological marker of vasculitis.     

Hypoglycemia enhances ionotropic but reduces metabotropic glutamate responses in substantia nigra dopaminergic neurons

It is widely accepted that energy deprivation causes a neuronal death that is mainly determined by an increase in the extracellular level of glutamate. Consequently an excessive membrane depolarization and a rise in the intracellular concentration of sodium and calcium are produced. In spite of this scenario, the function of excitatory and inhibitory amino acids during an episode of energy failure has not been studied yet at a cellular level. In a model of cerebral hypoglycemia in the rat substantia nigra pars compacta, we measured neuronal responses to excitatory amino acid agonists. Under single-electrode voltage-clamp mode at -60 mV, the application of the ionotropic glutamate receptor agonists N-methyl-D-aspartate, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid, kainate, and the metabotropic group I agonist (S)-3,5-dihydroxyphenilglycine (DHPG) produced reversible inward currents in the dopaminergic cells. In addition, an outward current was caused by the superfusion of the metabotropic GABA(B) agonist baclofen. Glucose deprivation enhanced the inward responses caused by each ionotropic glutamate agonist. In contrast, hypoglycemia depressed the DHPG-induced inward current and the baclofen-induced outward current. These effects of hypoglycemia were reversible. To test whether a failure of the Na(+)/K(+) ATPase pump could account for the modification of the agonist-induced currents during hypoglycemia, we treated the midbrain slices with strophanthidin (1-3 microM). Strophanthidin enhanced the inward currents caused by glutamate agonists. However, it did not modify the GABA(B)-induced outward current. Our data suggest that glucose deprivation enhances the inward current caused by the stimulation of ionotropic glutamate receptors while it dampens the responses caused by the activation of metabotropic receptors. Thus a substantial component of the augmented neuronal response to glutamate, during energy deprivation, is very likely due to the failure of Na(+) and Ca(2+) extrusion and might ultimately favor excitotoxic processes in the dopaminergic cells.     

Laterality effects in schizophrenia and bipolar disorder

There are numerous reports in the literature of lateralised structural cerebral abnormalities and alterations of the corpus callosum in the major psychoses. In the light of these findings the purpose of this study was to directly compare hemispheric differences and callosal interhemispheric transmission (IT) in schizophrenia and bipolar disorder. To do that we tested schizophrenic (SCZ), bipolar disorder (BD) patients and controls in a simple manual reaction time (RT) task with lateralised visual stimuli (Poffenberger paradigm) which enables one to test both laterality effects and IT time. We found an overall slowing of responses with the right hand in schizophrenics but not in bipolar patients, who, like controls, showed no hand differences. This selective slowing down of the right hand is likely to be related to abnormalities of intrahemispheric cortico-cortical connections in the left hemisphere. In contrast, IT time was similar in SCZ and BD patients and did not differ with respect to controls. Two are the novel findings of the present study: first both SZC and BD share a normal IT of visuomotor information despite the presence of callosal abnormalities. Second, an impairment of intrahemispheric left hemispheric processing is present only in SCZ patients. This represents a potentially important clue to a further understanding of the pathogenetic differences between the two major psychoses.     

Role of Intra‐Aortic Balloon Pump and Extracorporeal Membrane Oxygenation in Early Graft Failure After Cardiac Transplantation

Early graft failure (EGF) is a major risk factor for death after heart transplantation (Htx). We investigated the predictive risk factors for moderate‐to‐severe EGF requiring an intra‐aortic balloon pump (IABP) or extracorporeal membrane oxygenation (ECMO) circulatory support as treatment after Htx. Between January 2000 and December 2014, 412 consecutive adult patients underwent isolated Htx at our institution. Moderate and severe EGF were defined as the need for IABP and ECMO support, respectively, within 24 h after Htx. All available recipient and donor variables were analyzed to assess the risk of EGF occurrence. Overall, moderate‐to‐severe EGF occurred in 46 (11.1%) patients. Twenty‐nine (63.04%) patients required peripheral or central ECMO support in the treatment of severe EGF and 17 (36.9%) patients required IABP support for the treatment of moderate EGF. The predictive risk factors for moderate‐to‐severe EGF in recipients, as assessed by logistic regression analysis, were a preoperative transpulmonary gradient > 12 mm Hg (odds ratio [OR] 5.2; P = 0.023), a preoperative inotropic score > 10 (OR 8.5; P = 0.0001), and preoperative ECMO support (OR 4.2; P = 0.012). For donors, the predictive risk factor was a donor score ≥ 17 (OR 8.3; P = 0.006). The absence of EGF was correlated with improved long‐term survival: 94% at 1 year and 81% at 5 years without EGF versus 76% and 36% at 1 year (P < 0.001), and 70% and 28% at 5 years (P < 0.001) with EGF requiring IABP and ECMO support, respectively. In‐hospital weaned and survived patients after IABP or ECMO treatment for moderate‐to‐severe EGF had a similar 5‐year conditional survival rate as transplant patients who had not suffered EGF: 88% without EGF versus 84% with EGF treated with mechanical circulatory support devices (P = 0.08). The occurrence of EGF is a multifactorial deleterious event that depends on donor and recipient profiles. IABP and ECMO support are reliable treatment strategies, depending on the grade of EGF. Furthermore, surviving patients treated with IABP or ECMO have the same long‐term conditional survival rate as patients who have not suffered EGF.     

Suppression of the transcallosal motor output: a transcranial magnetic stimulation study in healthy subjects

We tested the hypothesis that transcranial magnetic stimulation (TMS), in addition to its inhibitory action on the corticospinal output, can also exert some inhibitory effect on the transcallosal system connecting the two motor cortices. In seven normal subjects, instructed to keep their right opponens pollicis (OP) muscle fully relaxed and their left OP muscle voluntarily contracted, we used a paired-pulse TMS protocol, to stimulate the left motor cortex. We evaluated the effect of low-intensity conditioning stimulation on the ipsilateral silent period (iSP) elicited by the subsequent test stimulus. Compelling evidence exists to support that this iSP is mediated by the activation of transcallosal motor fibres. Simultaneously, the inhibition of the motor evoked potential (MEP) in the right OP muscle was also investigated. At the interstimulus interval (ISI) of 3 ms, the iSP was significantly (P<0.0001, repeated-measures ANOVA) suppressed by conditioning intensities ranging from 1.2 to 0.6 of MEP threshold. The assessment of the time-course showed that iSP inhibition was present in all the tested subjects only at ISIs of 2 and 3 ms (for each subject P<0.05, repeated-measures ANOVA). Several findings suggest that the suppression of iSP is brought about by the activation of inhibitory mechanisms operating in the stimulated (left) motor cortex. We propose that the assessment of iSP suppression could be a method to study the excitability of intracortical inhibitory circuits in the affected hemisphere of patients with unilateral damage of the corticospinal tract.     

The significance of the prepubertal diabetes duration for the development of retinopathy and nephropathy in patients with type 1 diabetes

OBJECTIVE: A Danish nationwide prospective cohort of children and adolescents with type 1 diabetes was followed for 8 years to study the effect of the prepubertal duration of diabetes on early retinopathy and elevated albumin excretion rate (AER) (>20 microg/min). RESEARCH DESIGN AND METHODS: In 1989, blood glucose control (HbA(1c)) and AER was investigated in approximately 80% of all Danish children and adolescents with type 1 diabetes. A cohort of 339 young patients were restudied in 1995 including physical examination, demographic data, HbA(1c), AER, and fundus photography with central reading. Among the patients, a number of 304 had a prepubertal onset of diabetes defined as an onset age less than 11.7 years in girls and 12.9 years in boys. Microalbuminuria was defined as an AER of 20-150 microg min(-1) and macroalbuminuria as AER >150 microg min(-1) in two out of three timed overnight urine samples. RESULTS: At the follow-up in 1995-1996, no patients were younger than 12 years of age. The prevalence of any level of retinopathy was 17.7% in the age group 12-15 years, 45.4% from 16 to 20 years, and increased to 67.6% in patients more than 20 years of age. Diabetic retinopathy was significantly associated to poor long-term metabolic control (HbA(1c)) (P<.0001) and to diabetes duration both in patients with a prepubertal onset of disease as well as patients with a pubertal (P<.001) onset of disease. However, the pubertal diabetes duration contributed two times more than the prepubertal diabetes duration. Mean postpubertal diabetes duration to any retinopathy was significantly shorter (9.4 years) in patients with prepubertal onset of the disease compared to patients with postpubertal onset (11.8 years) (P=.0004). In total, the prevalence of elevated AER (>20 microg/min) increased from 4% in 1989 to 13% in 1995. None of the patients younger than 15 years of age had elevated AER, while the prevalence of elevated AER was about 14% from 15 years of age and onwards. Elevated AER in 1995 was significantly related to long-term metabolic control (P<.001) and elevated AER in the preceding years (P<.001) but was not correlated to diabetes duration neither before nor after the age of 12 years. CONCLUSION: The prepubertal diabetes duration is significantly associated with the development of diabetic retinopathy. The period, however, contributes less compared to the years after puberty. In concert with other studies, we found no association between raised AER and diabetes duration. This may be explained by the fact that other factors are more significant and dilute the significance of diabetes duration. Nonetheless, it seems prudent to optimise blood glucose control irrespective of age.     

The impact of route of delivery and presentation on twin neonatal and infant mortality: a population-based study in the USA, 1995–97

Objective: We examined whether the route of delivery for near-term (???34 weeks' gestation) twins, as candidates for vaginal delivery, affected neonatal and infant mortality rates. We further evaluated whether these mortality rates were modified by fetal presentation.

Methods: A population-based retrospective cohort study based on the matched multiple births data in the USA (1995–97) was performed. Analyses were restricted to non-malformed liveborn twins delivered at ??34 weeks' gestation. Twins with breech–breech and breech–vertex presentations were excluded, since they are not candidates for vaginal delivery. Neonatal mortality rates (death within the first 27 days) and post-neonatal mortality rates (death between 28 and 365 days) per 1000 twin live births, by route of delivery and fetal presentation, were derived. The associations between neonatal mortality, post-neonatal mortality and the route of delivery for vertex–breech versus vertex–vertex presentations were expressed based on relative risks (RR) and 95% confidence intervals (CI) derived from logistic regression models based on the method of generalized estimating equations.

Results: Of the 177?622 twins analyzed, 87% (n?=?154?531) presented as vertex-vertex. Fifty-five per cent (n?=?97?692) of twins were both delivered vaginally, 41% (n?=?72?825) were both delivered by Cesarean section and, of the remaining 4% (n?=?7105), the first twin was delivered vaginally and the second by Cesarean section. Twins with vertex–breech presentations delivered by Cesarean–cesarean sections, as well as those with vertex–vertex presentations delivered vaginally, had the lowest neonatal mortality rate (1.6 per 1000 live births). The highest neonatal mortality rate in the vertex–breech pairs occurred with vaginal–Cesarean deliveries (2.7 per 1000 live births). Among twins with vertex–vertex presentations, twins delivered via the vaginal–Cesarean route experienced the highest neonatal mortality (3.8 per 1000 live births). The RR for neonatal mortality in this group was 2.24 (95% CI 1.35, 3.72) compared with twins both delivered vaginally.

Conclusion: Route of delivery and fetal presentation both confer an impact on twin infant mortality rates. Strategies to reduce discordant routes in complicated vaginal deliveries may lead to improved neonatal survival.