Early postnatal GABAA receptor modulation reverses deficits in neuronal maturation in a conditional neurodevelopmental mouse model of DISC1.

Exploring drug targets based on disease-associated molecular mechanisms during development is crucial for the generation of novel prevention and treatment strategies for neurodevelopmental psychiatric conditions. We report that prefrontal cortex (PFC)-specific postnatal knockdown of DISC1 via in utero electroporation combined with an inducible knockdown expression system drives deficits in synaptic GABAA function and dendritic development in pyramidal neurons, as well as abnormalities in sensorimotor gating, albeit without profound memory deficits. We show for the first time that DISC1 is specifically involved in regulating cell surface expression of α2 subunit-containing GABAA receptors in immature developing neurons, but not after full maturation. Notably, pharmacological intervention with α2/3 subtype-selective GABAA receptor positive allosteric modulators during the early postnatal period ameliorates dendritic deficits and behavioral abnormalities induced by knockdown of DISC1. These findings highlight a critical role of DISC1-mediated disruption of postnatal GABA signaling in aberrant PFC maturation and function.

DISC1 regulates trafficking and processing of APP and Aß generation.

We report the novel regulation of proteolytic processing of amyloid precursor protein (APP) by DISC1, a major risk factor for psychiatric illnesses, such as depression and schizophrenia. RNAi knockdown of DISC1 in mature primary cortical neurons led to a significant increase in the levels of intracellular α-C-terminal fragment of APP (APP-CTFα) and the corresponding N-terminal-secreted ectodomain product sAPPα. DISC1 knockdown also elicited a significant decrease in the levels of amyloid beta (Aß)42 and Aß40. These aberrant proteolytic events were successfully rescued by co-expression of wild-type DISC1, but not by mutant DISC1 lacking the amino acids required for the interaction with APP, suggesting that APP-DISC1 protein interactions are crucial for the regulation of the C-terminal proteolysis. In a genetically engineered model in which a major full-length DISC1 isoform is depleted, consistent changes in APP processing were seen: an increase in APP-CTFα and decrease in Aß42 and Aß40 levels. Finally, we found that knockdown of DISC1 increased the expression of APP at the cell surface and decreased its internalization. The presented DISC1 mechanism of APP proteolytic processing and Aß peptide generation, which is central to Alzheimer's disease pathology, suggests a novel interface between neurological and psychiatric conditions.

At-home determination of 24-h urine sodium excretion: Validation of chloride test strips and multiple spot samples.

Sodium intake and compliance with dietary sodium modification are typically assessed using a 24-h urine collection analyzed using flame photometry, but this is inconvenient. Spot urine samples have been investigated as alternatives to 24-h collections, but their accuracy is poor. Since sodium and chloride are present in equal concentrations in dietary salt, chloride test strips may provide a suitable proxy for at-home measurement of urine sodium concentrations. We aimed to determine whether (i) chloride test strips provide a reliable measure of urinary sodium compared to the gold standard flame photometry and (ii) multiple spot samples accurately reflect 24-h urine sodium. We recruited 43 participants (19 males) aged 23.6 ± 0.6 years to complete multiple consecutive spot samples (morning and evening) along with a 24-h urine sodium collection. Urine 24-h sodium estimates using chloride test strips (114.6 ± 7.5 mmol/day) were highly correlated (r = 0.900, p < 0.0001) with flame photometry (121.1 ± 7.7 mmol/day) with a bias of -6.53 ± 22.2 mmol/day. Use of a three-spot sample average (both morning and evening spot samples) with a correction factor applied (122.9 ± 4.1 mmol/day) provided a good approximation of 24-h sodium measured by flame photometry (125.6 ± 9.0 mmol/day), with a bias of -2.55 ± 43.9 mmol/day. Chloride test strips applied to a 24-h urine collection provide a highly accurate measure of urinary sodium excretion, permitting convenient at-home sample collection and analysis. Their application to multiple spot samples provides a reasonable approximation of sodium excretion that can be used to conveniently monitor attempts at dietary sodium manipulation, without the inconvenience of completing a 24-h urine sample.

Reduction of plasma glutathione in psychosis associated with schizophrenia and bipolar disorder in translational psychiatry.

The establishment of mechanism-driven peripheral markers is important for translational psychiatry. Many groups, including ours, have addressed molecular alterations in peripheral tissues in association with symptomatic changes in major illnesses. Oxidative stress is implicated in the pathophysiology of schizophrenia (SZ) and bipolar disorder (BP) through studies of patient peripheral tissues and animal models. Although the relationship between peripheral changes and brain pathology remain elusive, oxidative stress may bridge such translational efforts. Nonetheless, the molecular substrates of oxidative stress are not well defined in mental conditions. Glutathione (GSH) is a non-enzymatic antioxidant that eliminates free radicals, and has been suggested to have a role in SZ. We performed a cross-sectional study of 48 healthy controls (CON), 52 SZ patients and 62 BP patients to compare the levels of peripheral GSH by a biochemical enzyme assay. We show a significant reduction of plasma GSH in both SZ and BP patients compared with CON. We evaluated possible influences of clinical characteristics on the level of GSH in SZ and BP. A decrease in GSH level correlated with Positive and Negative Syndrome Scale (PANSS) total and positive scores for SZ and correlated with the PANSS general for BP. Taken together, we provide evidence that SZ and BP display a common molecular signature in the reduction of peripheral GSH in the psychosis dimension.

Clinical utility of neuronal cells directly converted from fibroblasts of patients for neuropsychiatric disorders: studies of lysosomal storage diseases and channelopathy.

Methodologies for generating functional neuronal cells directly from human fibroblasts [induced neuronal (iN) cells] have been recently developed, but the research so far has only focused on technical refinements or recapitulation of known pathological phenotypes. A critical question is whether this novel technology will contribute to elucidation of novel disease mechanisms or evaluation of therapeutic strategies. Here we have addressed this question by studying Tay-Sachs disease, a representative lysosomal storage disease, and Dravet syndrome, a form of severe myoclonic epilepsy in infancy, using human iN cells with feature of immature postmitotic glutamatergic neuronal cells. In Tay-Sachs disease, we have successfully characterized canonical neuronal pathology, massive accumulation of GM2 ganglioside, and demonstrated the suitability of this novel cell culture for future drug screening. In Dravet syndrome, we have identified a novel functional phenotype that was not suggested by studies of classical mouse models and human autopsied brains. Taken together, the present study demonstrates that human iN cells are useful for translational neuroscience research to explore novel disease mechanisms and evaluate therapeutic compounds. In the future, research using human iN cells with well-characterized genomic landscape can be integrated into multidisciplinary patient-oriented research on neuropsychiatric disorders to address novel disease mechanisms and evaluate therapeutic strategies.

Etiology and risk factors of 180 cases of native valve endocarditis. Report from a 5-year national prospective survey in Slovak Republic.

Risk factors, etiology, and outcome of 180 cases of infective endocarditis (IE) in the Slovak Republic for 5 years were prospectively studied in a national survey. According to the Duke Endocarditis Service Criteria (1994), 169 cases were considered definitive and 21 possible/probable. The aortic valve was infected in 46.7%, mitral in 47.2%, and tricuspidal/pulmonary in 6.1% of cases. The majority of endocarditis cases was caused by Staphylococcus aureus and coagulase-negative staphylococci (CNS) (33.3%); only 12.2% were due to viridans streptococci; 11.7% were due to Enterococcus faecalis; 6.1% due to Haemophilus spp.; 10.1% due to other organisms; and 26.7% were culture negative. Single positive cultures of CNS were not considered clinically significant. More than 25% of 180 patients were older than 60 years. Rheumatic fever was a risk factor in 35.5%, dental surgery in 20.5%, prior cardiosurgery in 7.8%, and neoplasia in 6.7%. All patients were treated with antimicrobials (average length of therapy was 29.5 days) and 33.3% of patients also had surgery (valvular prosthesis replacement). Forty (22.2%) died, and 140 (77.8%) survived at day 60 after the diagnosis of endocarditis was made. All 40 deaths were attributable to infection. Univariate analysis comparing deaths and survivors did not show significant differences in most of the recorded risk factors between both groups, except age > 60 (40.0% versus 21.4%, p < 0.05), staphylococcal etiology (55.0% versus 27.1%, p < 0.04), and antibiotic therapy < 21 days (without surgery) (65.0% versus 3.6%, p < 0.01). These risk factors were significantly more frequently associated with deaths. Viridans streptococcal IE and surgical therapy in addition to antibiotics were associated with lower mortality in comparison to staphylococcal endocarditis (p < 0.045) or to cases treated with antibiotics only (p < 0.05). In comparison to other nationally based surveys in Europe (Greece, Croatia, France), the percentage of culture-negative endocarditis and spectrum of pathogens differed significantly.

Native valve staphylococcal endocarditis: etiology, risk factors and outcome in 53 cases.

Fifty-three cases of staphylococcal endocarditis from a national endocarditis survey were analyzed for risk factors and outcome. Thirty of 53 patients had predisposing heart disease (39.6% rheumatic fever) but only 3 were on dialysis, only 2 had central venous catheter, only 2 intravenous drug abuse but 7 had prior cardiosurgery. Mortality was 39.6%. In analyzing risk factors for death, attributable mortality was significantly associated with skin infections (P < 0.05), embolization (P < 0.02), inappropriate therapy (P < 0.005) either because of too short therapy (P < 0.003) or wrong antibiotic combination (P < 0.01). Surgical therapy was associated with better outcome (4.8% deaths vs. 31.2% survivors, P < 0.04).

[Acute intermittent porphyria]. / Akútna intermitentná porfýria.

Acute intermittent porphyria is an autosomal dominant condition caused by a genetic defect of the deaminase gene located on the 11. chromosome. Due to this defect only 50% of the normal enzyme quantity is produced. The disease becomes manifested only in the case of increased demands on given metabolic pathway resulting in porphobilinogen accumulation and storage in the organism. Clinical pattern involves abdominal, neurologic and psychiatric symptomatology. Laboratory diagnosis is based on the detection of delta-aminolevulinic acid, porphobilinogen, uroporphyrin and coproporphyrin in the urine. Between the attacks may only the detection of porphobilinogen deaminase in erythrocytes, leukocytes and skin fibroblasts be positive. The therapy is based on infusions of 20% glucose solution and hydromineral imbalance correction. When neurologic symptoms occur it is necessary to administer hem-arginate intravenously. The case report presents almost textbook case of a young female patient suffering from the disease. (Ref. 7.)

[Catecholamines and changes in blood pressure during stress tests in type 1 diabetics]. / Katecholamíny a zmeny krvného tlaku pocas zát'azových testov u diabetikov 1. typu.

The influence of metabolic control on catecholamine secretion and blood pressure during upright posture, mental stress and physical exercise was studied in 34 normotensive normoalbuminuric type 1 (insulin-dependent) diabetic patients without autonomic neuropathy. A poor metabolic control did not induce different changes in blood pressure and plasma catecholamines as compared to a good metabolic control, except for an exaggerated rise in plasma adrenaline in patients with asymptomatic hypoglycemia. The lack of correlation between plasma catecholamines and blood pressure suggest that some other factors are also involved in the hemodynamic reaction to mental stress and physical exercise in diabetic patients. (Fig. 2, Tab. 3, Ref. 25.).

[Intracavitary thrombosis--unusual complications in ulcerative colitis]. / Intrakavitárny trombus--neobvyklá komplikácia pri ulceróznej kolitíde.

The statement of echocardiographic differential diagnosis of intracavitary masses is not simple even for an experienced echocardiographist. It is mainly caused by the resemblance in echo-densities of thrombi and myxoma. Atypical localization of masses makes the differential diagnosis even more difficult. Authors report a case of a 30 year-old man with the history of ulcerative colitis, in whom sepsis occurred as a complication of an inflammatory bowel disease. They report the diagnosis of thrombus in the right atrium, probably of infectious genesis, formed on the endocardium which had been damaged by a catheter tip and potentiated by activated coagulatory system. In the documented period, histological examinations of colonoscopic and peroperative biopsies were performed repetitively. Neither these examinations answered the question of differential diagnosis between ulcerative colitis and Crohn's disease. The authors report an echocardiographic diagnosis and they follow-up the genesis and subsequent disappearance of the pathological mass in the right atrium which was finally diagnosed as a thrombus. The final diagnosis was based on the clinical follow-up and disappearance of the mass. (Fig. 3, Ref. 7.).

[Comparison of the glomerular filtration rate using renal plasma clearance of 51Cr-EDTA and biochemical methods]. / Porovnanie glomerulárnej filtrácie stanovenej renálnym plazmatickým clearance 51Cr-EDTA a biochemickými metódami.

In 22 patients (age 19 to 73 years) the authors examined the glomerular filtration by assessing the renal clearance of 51Cr-EDTA in addition to the plasmatic method with several blood samples, methods with a smaller number of blood samples and external assessment of the radioactivity, or else by estimation of the creatinine clearance by biochemical methods. They used as the reference method assessment of the renal plasma clearance of 51Cr-EDTA by means of a one-compartment model from the radioactivity of blood samples collected during the 60th, 120th and 180th minute. It was revealed that for the normal value of glomerular filtration (GF = 1.8 ml/s) and for its reduced value (GF = 0.5 ml/s), as compared with the reference method RP, the highest external and internal accuracy, i.e. the best agreement with the reference method and the closest interval estimates, are obtained by the single sample method RE (blood sample during the 120th minute), supplemented by three external assessments of radioactivity during the 50th-70th, 110th-130th and 170th-190th minute. The regression relationship of these methods is expressed by the following equations: RE = -8.9 + 1.06 . RP; RP = 8.47 + 0.94 . RE. The biochemical methods were, as compared with the radionuclide ones, less accurate. Their accuracy declined in the order from the calculated creatinine clearance according to Cockcroft and Gault via the inverse value of the serum creatinine concentration towards the 24-hour creatinine clearance.

[The syndrome of inappropriate secretion of antidiuretic hormone in hypophyseal tumors]. / Syndróm neprimeranej sekrécie antidiuretického hormónu pri nádore hypofýzy.

70-year old man was admitted to the hospital due to the sudden change in his behaviour with the production of unusual echolalic word connections. Arginin-vasopressin (AVP) level (1.16 pg/ml) was found inappropriately higher in relation to the severe serum hypoosmolality (261 mmol/kg) and hyponatraemia (117 mmol/l) with relatively high urinary osmolality (590 mmol/kg) and natriuria (684 mmol/24 h). Diagnosis of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH-type C) was confirmed during the water load test. Magnetic resonance imaging and CT scans revealed in the region of hypophysis intrasellar tumour (diameter of 16 mm) and the stabilized finding of temporal cyst. Substitution of sodium losses with the restricted fluid intake resulted in the correction of water-electrolyte balance and the restoration of normal clinical state.

Bax-mediated cell death by the Gax homeoprotein requires mitogen activation but is independent of cell cycle activity.

Tissues with the highest rates of proliferation typically exhibit the highest frequencies of apoptosis, but the mechanisms that coordinate these processes are largely unknown. The homeodomain protein Gax is down-regulated when quiescent cells are stimulated to proliferate, and constitutive Gax expression inhibits cell proliferation in a p21(WAF/CIP)-dependent manner. To understand how mitogen-induced proliferation influences the apoptotic process, we investigated the effects of deregulated Gax expression on cell viability. Forced Gax expression induced apoptosis in mitogen-activated cultures, but quiescent cultures were resistant to cell death. Though mitogen activation was required for apoptosis, neither the cdk inhibitor p21(WAF/CIP) nor the tumor suppressor p53 was required for Gax-induced cell death. Arrest in G1 or S phases of the cell cycle with chemical inhibitors also did not affect apoptosis, further suggesting that Gax-mediated cell death is independent of cell cycle activity. Forced Gax expression led to Bcl-2 down-regulation and Bax up-regulation in mitogen-activated, but not quiescent cultures. Mouse embryonic fibroblasts homozygous null for the Bax gene were refractive to Gax-induced apoptosis, demonstrating the functional significance of this regulation. These data suggest that the homeostatic balance between cell growth and death can be controlled by mitogen-dependent pathways that circumvent the cell cycle to alter Bcl-2 family protein expression.

Multiple Bcl-2 family members demonstrate selective dimerizations with Bax.

A family of Bcl-2-related proteins regulates cell death and shares highly conserved BH1 and BH2 domains. BH1 and BH2 domains of Bcl-2 were required for it to heterodimerize with Bax and to repress apoptosis. A yeast two-hybrid assay accurately reproduced this interaction and defined a selectivity and hierarchy of further dimerizations. Bax also heterodimerizes with Bcl-xL, Mcl-1, and A1. A Gly-159-->Ala substitution in BH1 of Bcl-xL disrupted its heterodimerization with Bax and abrogated its inhibition of apoptosis in mammalian cells. This suggests that the susceptibility to apoptosis is determined by multiple competing dimerizations in which Bax may be a common partner.

Clinical experience with the single-plate Molteno implant in complicated glaucomas. Update of a pilot study.

Ninety-six patients who had undergone single-plate Molteno implantation for glaucomas with poor surgical prognoses were re-evaluated for long-term results. Control of intraocular pressure was achieved with one single-plate implant to a level less than 22 mmHg (but greater than 5 mmHg) without reoperation or devastating complications in 46% of the aphakic/pseudophakic eyes, 25% of eyes after failed filters, 25% of eyes with neovascular glaucomas, and 26% of eyes in patients younger than 13 years of age (life-table analysis at 5 years). Five-year success rates improved to 53%, 71%, 40%, and 56%, respectively, when data from second plates were included. Visual acuities improved or remained the same after one or two plates were implanted in 47% of aphakic/pseudophakic eyes, 17% of eyes after failed filters, 65% of eyes with neovascular glaucomas, and 63% of eyes in patients younger than 13 years of age on whom Snellen acuity was available. The most frequent overall complications after implantation of one or two plates included: corneal edema (19%), corneal graft decompensation (13%), and cornea-tube touch, retinal detachment, and cataract (8% each).

Hematopoietic malignancies demonstrate loss-of-function mutations of BAX.

The BCL-2 gene family regulates the susceptibility to apoptotic cell death in many cell types during embryonic development and normal tissue homeostasis. Deregulated expression of anti-apoptotic BCL-2 can be a primary aberration that promotes malignancy and also confers resistance to chemotherapeutic agents. Recently, studies of Bax-deficient mice have indicated that the pro-apoptotic BAX molecule can function as a tumor suppressor. Consequently, we examined human hematopoietic malignancies and found that approximately 21% of lines possessed mutations in BAX, perhaps most commonly in the acute lymphoblastic leukemia subset. Approximately half were nucleotide insertions or deletions within a deoxyguanosine (G8) tract, resulting in a proximal frame shift and loss of immunodetectable BAX protein. Other BAX mutants bore single amino acid substitutions within BH1 or BH3 domains, demonstrated altered patterns of protein dimerization, and had lost death-promoting activity. Thus, mutations in the pro-apoptotic molecule BAX that confer resistance to apoptosis are also found in malignancies.