A CRISPR-Cas9-engineered mouse model for GPI-anchor deficiency mirrors human phenotypes and exhibits hippocampal synaptic dysfunctions.

Pathogenic germline mutations in PIGV lead to glycosylphosphatidylinositol biosynthesis deficiency (GPIBD). Individuals with pathogenic biallelic mutations in genes of the glycosylphosphatidylinositol (GPI)-anchor pathway exhibit cognitive impairments, motor delay, and often epilepsy. Thus far, the pathophysiology underlying the disease remains unclear, and suitable rodent models that mirror all symptoms observed in human patients have not been available. Therefore, we used CRISPR-Cas9 to introduce the most prevalent hypomorphic missense mutation in European patients, Pigv:c.1022C > A (p.A341E), at a site that is conserved in mice. Mirroring the human pathology, mutant Pigv341E mice exhibited deficits in motor coordination, cognitive impairments, and alterations in sociability and sleep patterns, as well as increased seizure susceptibility. Furthermore, immunohistochemistry revealed reduced synaptophysin immunoreactivity in Pigv341E mice, and electrophysiology recordings showed decreased hippocampal synaptic transmission that could underlie impaired memory formation. In single-cell RNA sequencing, Pigv341E-hippocampal cells exhibited changes in gene expression, most prominently in a subtype of microglia and subicular neurons. A significant reduction in Abl1 transcript levels in several cell clusters suggested a link to the signaling pathway of GPI-anchored ephrins. We also observed elevated levels of Hdc transcripts, which might affect histamine metabolism with consequences for circadian rhythm. This mouse model will not only open the doors to further investigation into the pathophysiology of GPIBD, but will also deepen our understanding of the role of GPI-anchor-related pathways in brain development.

Aversive olfactory associative memory loses odor specificity over time.

Avoiding associatively learned predictors of danger is crucial for survival. Aversive memories can, however, become counter-adaptive when they are overly generalized to harmless cues and contexts. In a fruit fly odor-electric shock associative memory paradigm, we found that learned avoidance lost its specificity for the trained odor and became general to novel odors within a day of training. We discuss the possible neural circuit mechanisms of this effect and highlight the parallelism to over-generalization of learned fear behavior after an incubation period in rodents and humans, with due relevance for post-traumatic stress disorder.

Branch point strength controls species-specific CAMK2B alternative splicing and regulates LTP.

Regulation and functionality of species-specific alternative splicing has remained enigmatic to the present date. Calcium/calmodulin-dependent protein kinase IIß (CaMKIIß) is expressed in several splice variants and plays a key role in learning and memory. Here, we identify and characterize several primate-specific CAMK2B splice isoforms, which show altered kinetic properties and changes in substrate specificity. Furthermore, we demonstrate that primate-specific CAMK2B alternative splicing is achieved through branch point weakening during evolution. We show that reducing branch point and splice site strengths during evolution globally renders constitutive exons alternative, thus providing novel mechanistic insight into cis-directed species-specific alternative splicing regulation. Using CRISPR/Cas9, we introduce a weaker, human branch point sequence into the mouse genome, resulting in strongly altered Camk2b splicing in the brains of mutant mice. We observe a strong impairment of long-term potentiation in CA3-CA1 synapses of mutant mice, thus connecting branch point-controlled CAMK2B alternative splicing with a fundamental function in learning and memory.

[Non-dialysis chronic kidney disease in primary care - a questionnaire study among general practitioners]. / Nicht dialysepflichtige, chronische Niereninsuffizienz in der Hausarztpraxis ­ eine Fragebogenstudie unter Hausärzten.

BACKGROUND: The majority of patients with non-dialysis chronic kidney disease are cared for by general practitioners. Especially for Germany, the evidence of this topic is still very low. The aim of the survey was to estimate the perceived frequency of non-dialysis chronic kidney disease in general practice, the use of diagnostics and therapy, used tools considering the professional background and experience of the responding general practitioners. METHODS: A questionnaire was self-designed in the cooperation of several disciplines. 1130 general practitioners from Saxony and Saxony-Anhalt were randomly selected and the questionnaire was sent by post. Data were collected from June 2019 to July 2019. RESULTS: Of the 1,130 questionnaires sent, 372 returned analysable (response rate: 32.9 %). The prevalence of non-dialysis chronic kidney disease was estimated to be 6-15 %. 97 % of the general practitioners rated the adjustment of high blood pressure and diabetes mellitus as a high to very high priority. Concerning the diagnosis of proteinuria, the use of a urine dipstick test was stated by 60.8 % of the respondents and the requirement for an albumin/creatinine-ratio was stated by 22.6 %. Only a few differences could be revealed in the response behavior of the participating groups of doctors. Working experience is an important factor in choosing tools, especially guidelines. CONCLUSIONS: The results showed that the doctors interviewed followed international recommendations for the care of patients with non-dialysis chronic kidney disease. However, improvements in progression diagnostics are necessary and important. General practitioners and internal medicines working as general practitioners have a comparable level of competence in the primary medical care of the non-dialysis chronic kidney disease. Significant differences were created by the professional experience of the doctors. KEY POINTS: · General practitioners estimate the prevalence of non-dialysis chronic kidney disease in their practice at 6-15 %.. · Using the albumin/creatinine-ratio for proteinuria diagnostics is requested too rarely compared to the urine dipstick test.. · General practitioners, specialists in general medicine and internists working in general medicine have a comparable level of competence to treat patients with non-dialysis chronic kidney disease.. · Working experience is an important factor in choosing tools, especially guidelines..

Functional architecture of reward learning in mushroom body extrinsic neurons of larval Drosophila.

The brain adaptively integrates present sensory input, past experience, and options for future action. The insect mushroom body exemplifies how a central brain structure brings about such integration. Here we use a combination of systematic single-cell labeling, connectomics, transgenic silencing, and activation experiments to study the mushroom body at single-cell resolution, focusing on the behavioral architecture of its input and output neurons (MBINs and MBONs), and of the mushroom body intrinsic APL neuron. Our results reveal the identity and morphology of almost all of these 44 neurons in stage 3 Drosophila larvae. Upon an initial screen, functional analyses focusing on the mushroom body medial lobe uncover sparse and specific functions of its dopaminergic MBINs, its MBONs, and of the GABAergic APL neuron across three behavioral tasks, namely odor preference, taste preference, and associative learning between odor and taste. Our results thus provide a cellular-resolution study case of how brains organize behavior.

The cataract situation in Suriname: an effective intervention programme to increase the cataract surgical rate in a developing country.

AIMS: To provide an overview of cataract data in Suriname and to describe and evaluate a programme to control cataract blindness in a developing country. DESIGN: Evaluation of hospital data and findings from a population-based cross-sectional survey. METHODS: The implementation of a new cataract surgical intervention programme was described and retrospectively evaluated by analysing the number of cataract operations and other related indicators at the Suriname Eye Centre (SEC) in the period 2006-2014. Findings of the recent Rapid Assessment of Avoidable Blindness (2013-2014) survey were used to evaluate the national cataract situation in Suriname in people aged ≥50 years (n=2998), including prevalence of cataract blindness, outcome and cataract surgical rate (CSR). RESULTS: Since the implementation of a new cataract intervention programme, the number of cataract operations at the SEC has increased from 1150 in 2006 to 4538 in 2014, leading to an estimated national CSR of 9103 per one million inhabitants. The prevalence of bilateral cataract blindness in Suriname was 0.8% (95% CI 0.2% to 1.3%) in individuals aged ≥50 years. The proportion of eyes with a postoperative visual acuity <6/60 (poor outcome) was lowest in eyes operated at the SEC (8.5%) and highest in surgeries performed by foreign humanitarian ophthalmic missions. CONCLUSIONS: The cataract situation in Suriname is well under control since the implementation of the new intervention programme. Important factors contributing to this success were the introduction of phacoemulsification, intensive training, and improvement in the affordability and accessibility of cataract surgery. The proportion of poor outcomes was still >5%.

Diabetes and diabetic retinopathy in people aged 50†years and older in the Republic of Suriname.

BACKGROUND/AIMS: Population-based surveys on diabetes and diabetic retinopathy (DR) are necessary to increase awareness and develop screening and therapeutic programmes. The aim was to estimate the prevalence of DR in older adults of different ethnic backgrounds in Suriname. METHODS: Fifty clusters of 60 people aged ≥50 years were randomly selected with a probability proportional to the size of the population unit. Eligible people were randomly selected through compact segment sampling and examined using the Rapid Assessment of Avoidable Blindness plus Diabetic Retinopathy (RAAB + DR) protocol. Participants were classified as having diabetes if they: were previously diagnosed with diabetes; were receiving treatment for glucose control; had a random blood glucose level >200 mg/dL. These participants were dilated for funduscopy, assessed for DR following the Scottish DR grading protocol and evaluated for ethnicity and DR ophthalmic screening frequencies. RESULTS: A total of 2806 individuals was examined (response 93.6%). The prevalence of diabetes was 24.6%. In these patients any type of DR and/or maculopathy occurred in 21.6% and sight-threatening DR in 8.0%. Of the known diabetics, 34.2% never had an eye examination for DR and in 13.0% the last examination was >24 months ago. The prevalence of diabetes was significantly higher in Hindustani people compared with other major ethnic groups. CONCLUSIONS: The prevalence of diabetes and diabetics without regular DR control in people aged ≥50 years in Suriname was higher than expected. The uptake for special services for DR has to be expanded to decrease patient delay and DR-induced blindness.

Epidemiology and aetiology of childhood ocular trauma in the Republic of Suriname.

PURPOSE: To describe the epidemiology and aetiology of ocular trauma in school-aged children who previously visited the Suriname Eye Centre (SEC) of the Academic Hospital Paramaribo. METHODS: In a hospital-based retrospective study, all cases of children who were school aged (8-15 years) at the time of the survey and previously underwent evaluation and/or treatment at the SEC because of ocular trauma were analysed. Demographic and ophthalmologic data were taken out of patient records; eye injuries were classified using the Birmingham Eye Trauma Terminology classification system. Main outcome measures were type of injury, mechanism/cause of injury, final visual acuity (VA), hospitalization, patient delay and patient compliance. RESULTS: Five hundred and thirty-eight records were analysed which included 35 open globe injuries (OGI) (7%), 458 closed globe injuries (85%), five orbital fractures (1%) and 40 eyelid injuries (7%). The most frequent causes of trauma represented body parts (18%) and sticks or branches (13%) and resulted from poking (20%) or punching (13%) the eye. Final VA < 6/60 was reported in 58% of registered OGI. Where living in rural areas (p = 0.007), OGI (p < 0.0001) and poor compliance to scheduled check-ups (p < 0.0001) were statistically significantly related to an unfavourable outcome, patient delay was not. Patients having OGI were more often hospitalized than children with other injuries (p < 0.0001). CONCLUSION: This is the first study providing data on childhood ocular trauma in Suriname. As the majority of childhood injuries were avoidable, new policies should aim at developing effective, targeted preventive strategies to promote awareness, parental supervision, immediate action and compliance.

Effects of isoflurane with and without dexmedetomidine or remifentanil on heart rate variability before and after nociceptive stimulation at different multiples of minimum alveolar concentration in dogs.

OBJECTIVE: To evaluate the influence of 3 anesthetic protocols and multiples of minimum alveolar concentration (MAC) on heart rate variability (HRV) with and without nociceptive stimulation in dogs. ANIMALS: 6 healthy adult Beagles. PROCEDURES: Each dog was anesthetized 3 times: with isoflurane alone, with isoflurane and a constant rate infusion of dexmedetomidine (IsoD; 3 µg/kg/h, IV), and with isoflurane and a constant rate infusion of remifentanil (IsoR; 18 µg/kg/h, IV). Individual MAC was determined via supramaximal electrical stimulation. Sinus rhythm-derived intervals between 2 adjacent R-R intervals were exported from ECG recordings. Selected HRV time and frequency domain variables were obtained (at 2-minute intervals) and analyzed offline with signed rank tests before and after stimulation at 0.75, 1.0, and 1. 5 MAC for each anesthetic session. RESULTS: The isoflurane session had the overall lowest prestimulation SDNN (SD of all R-R intervals) values. Prestimulation SDNN values decreased significantly with increasing MAC in all sessions. For the IsoD session, SDNN (milliseconds) or high-frequency power (milliseconds(2)) was inversely correlated with MAC (Spearman rank correlation coefficient for both variables, -0.77). In the isoflurane and IsoR sessions, heart rate increased significantly after stimulation. In the IsoD session, poststimulation SDNN was increased significantly, compared with prestimulation values, at 0.75 and 1.0 MAC. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of SDNN and high-frequency power values, anesthetic levels between 0.75 and 1.5 MAC within the same anesthetic protocol could be differentiated, but with a large overlap among protocols. Usefulness of standard HRV variables for assessment of anesthetic depth and nociception in dogs is questionable.

Causes of severe visual impairment and blindness in children in the Republic of Suriname.

AIMS: To determine the causes of severe visual impairment and blindness (SVI/BL) in children in Suriname (Dutch Guyana) and to identify preventable and treatable causes. METHODS: 4643 children under 16 years of age were recruited from two locations: 33 children attending the only school for the blind were examined and 4610 medical records were analysed at an eye clinic. Data have been collected using the WHO Prevention of Blindness Programme eye examination record for children. RESULTS: 65 children were identified with SVI/BL, 58.5% were blind and 41.5% were severely visually impaired (SVI). The major anatomical site of SVI/BL was the retina in 33.8%, lens in 15.4% and normal appearing globe in 15.4%. The major underlying aetiology of SVI/BL was undetermined in 56.9% (mainly cataract and abnormality since birth) and perinatal factors 21.5% (mainly retinopathy of prematurity (ROP)). Avoidable causes of SVI/BL accounted for 40% of cases; 7.7% were preventable and 32.3% were treatable with cataracts and ROP the most common causes (15.4% and 12.3%, respectively). CONCLUSIONS: More than a third of the SVI/BL causes are potentially avoidable, with childhood cataract and ROP the leading causes. Corneal scarring from vitamin A deficiency does not seem to be a continuing issue in Suriname.