"Virtual patch clamp analysis" for predicting the functional significance of pathogenic variants in sodium channels.

OBJECTIVE: Opening of voltage-gated sodium channels is crucial for neuronal depolarization. Proper channel opening and influx of Na+ through the ion pore, is dependent upon binding of Na+ ion to a specific amino-acid motif (DEKA) within the pore. In this study we used molecular dynamic simulations, an advanced bioinformatic tool, to research the dysfunction caused by pathogenic variants in SCN1a, SCN2a and SCN8a genes. METHOD: Molecular dynamic simulations were performed in six patients: three patients with Dravet syndrome (p.Gly177Ala,p.Ser259Arg and p.Met1267Ile, SCN1a), two patients with early onset drug resistant epilepsy(p.Ala263Val, SCN2a and p.Ile251Arg, SCN8a), and a patient with autism (p.Thr155Ala, SCN2a). After predicting the 3D-structure of mutated proteins by homology modeling, time dependent molecular dynamic simulations were performed, using the Schrödinger algorithm. The opening of the sodium channel, including the detachment of the sodium ion to the DEKA motif and pore diameter were assessed. Results were compared to the existent patch clamp analysis in four patients, and consistency with clinical phenotype was noted. RESULTS: The Na+ ion remained attached to DEKA filter longer when compared to wild type in the p.Gly177Ala, p.Ser259Arg,SCN1a, and p.Thr155Ala, SCN2a variants, consistent with loss-of-function. In contrast, it detached quicker from DEKA than wild type in the p.Ala263Val,SCN2a variant, consistent with gain-of-function. In the p.Met1267Ile,SCN1a variant, detachment from DEKA was quicker, but pore diameter decreased, suggesting partial loss-of-function. In the p.Leu251Arg,SCN8a variant, the pore remained opened longer when compared to wild type, consistent with a gain-of-function. The molecular dynamic simulation results were consistent with the existing patch-clamp analysis studies, as well as the clinical phenotype. SIGNIFICANCE: Molecular dynamic simulation can be useful in predicting pathogenicity of variants and the disease phenotype, and selecting targeted treatment based on channel dysfunction. Further development of these bioinformatic tools may lead to "virtual patch-clamp analysis".

Asymptomatic idiopathic intracranial hypertension in children.

OBJECTIVE: To define characteristics of pediatric asymptomatic idiopathic intracranial hypertension (IIH). PATIENTS AND METHODS: We retrospectively reviewed our Neuro-Ophthalmology database (2000-2006) for all cases of symptomatic and asymptomatic pediatric IIH. RESULTS: Out of 45 IIH cases, 14 (31.1%) were asymptomatic (incidental examination). When compared with children with symptomatic IIH, asymptomatic cases were younger [5.6 (1.8-15) vs 11.0 (5-17) years, P = 0.007], had lower percentage of obesity (14.3% vs 48.4%, P = 0.046), and had male predominance (71.4% vs 38.7%, P = 0.06). Asymptomatic cases required shorter duration of acetazolamide treatment [3 (0-8), vs 6 (0-20) months, P = 0.021], and resulted in complete resolution of swollen discs. CONCLUSIONS: We speculate that asymptomatic IIH may be more common in young children and could represent a milder form or a presymptomatic phase before evolving into classic symptomatic IIH. Further studies to assess the clinical significance of asymptomatic IIH are warranted.

Electromagnetic navigation improves minimally invasive robot-assisted lung brachytherapy.

OBJECTIVE: Recent advances in minimally invasive thoracic surgery have renewed an interest in the role of interstitial brachytherapy for lung cancer. Our previous work has demonstrated that a minimally invasive robot-assisted (MIRA) lung brachytherapy system produced results that were equal to or better than those obtained with standard video-assisted thoracic surgery (VATS) and comparable to results with open surgery. The purpose of this project was to evaluate the performance of an integrated system for MIRA lung brachytherapy that incorporated modified electromagnetic navigation and ultrasound image guidance with robotic assistance. METHODS: The experimental test-bed consisted of a VATS box, ZEUS and AESOP surgical robotic arms, a seed injector, an ultrasound machine, video monitors, a computer, and an endoscope. Our previous custom-designed electromagnetic navigational software and the robotic controller were modified and incorporated into the MIRA III system to become the next-generation MIRA IV. Inactive brachytherapy seeds were injected as close as possible to a small metal ball target embedded in an opaque agar cube. The completion time, the number of attempts, and the accuracy of seed deployment were compared for manual placement, standard VATS, MIRA III, and the new MIRA IV system. RESULTS: The MIRA IV system significantly reduced the median procedure time by 61% (104 s to 41 s), tissue trauma by 75% (4 attempts to 1 attempt), and mean seed placement error by 64% (2.5 mm to 0.9 mm) when compared to a standard VATS. MIRA IV also reduced the mean procedure time by 48% (85 s to 44 s) and the seed placement error by 68% (2.8 mm to 0.9 mm) compared to the MIRA III system. CONCLUSIONS: A modified integrated system for performing minimally invasive robot-assisted lung brachytherapy was developed that incorporated electromagnetic navigation and an improved robotic controller. The MIRA IV system performed significantly better than standard VATS and better than MIRA III.

Effects of three H2 antagonists on the isolated perfused rat liver. Correlation of bile flow changes with potential for causing hepatic disease in patients.

The adverse effects of oxmetidine, an H2 blocking agent which has been shown to produce hepatic injury in 1-4% of patients, on an in vitro model were compared with those of cimetidine and ranitidine which have led to only rare instances of hepatic injury. Bile flow was measured in the isolated perfused rat liver (Wistar rats), comparing the effects of each of the three drugs with control perfusions. Oxmetidine in concentrations of 3 X 10(-3) M or greater led to a decrease in bile flow within 15 min and, at a concentration of 5 X 10(-3) M, to complete cessation of flow within 5 min. Lower concentrations (5 X 10(-4) M) led to a marked choleresis. Ranitidine and cimetidine in concentrations up to 5 X 10(-3) M produced no decrease in bile flow. Ranitidine, however, led to a choleresis at a concentration of 5 X 10(-3) M. The positive correlation between in vivo and in vitro toxicity supports the view that in vitro testing may prove to be of use in predicting the hepatotoxic potential of a drug.

Massive thrombosis as a result of triple infestation of the pulmonary arterial circulation by Ascaris, Candida, and Mucor.

A 35-year-old man with a brief history of dyspnea and fever experienced rapid progressive respiratory distress and died shortly after being hospitalized. Postmortem examination revealed thrombotic occlusion of the pulmonary tree; the thrombotic material showed Ascaris lumbricoides, Candida albicans, and Mucor. This rare coincidence is an unexpected complication of ascariasis that has not been described previously.

Localized Wegener's granulomatosis relapsing as diffuse massive intra-alveolar hemorrhage.

In a 75-year-old patient presenting with a solitary pulmonary mass, a localized form of Wegener's granulomatosis was diagnosed after lobectomy. In the absence of extrapulmonary manifestations and after a benign postoperative course, the patients was discharged without medical treatment. Three months later, diffuse alveolar hemorrhage developed abruptly, necessitating mechanical ventilation, and was followed by cardiac complications and a fatal outcome. This case and another previously reported strongly suggest the need for medical treatment in patients with a localized form of pulmonary Wegener's granulomatosis, even when complete remission after surgical resection of the lung lesion seems to have been achieved.

Digoxin quinidine interaction: a pharmacokinetic study in the isolated perfused rat liver.

Digoxin-quinidine interaction was studied in the experimental model of isolated perfused rat liver. Neither digoxin nor quinidine were toxic to the isolated rat liver. The clearance of digoxin and quinidine by the liver was directly related to the rate of bile flow and the size of the initial dose of digoxin. In the presence of quinidine, after initial doses of digoxin of 0.5 and 1 micrograms, the concentration of digoxin in the perfusate was increased 2.5 and 3-fold. Its excretion in the bile was reduced by 45% and 20.5%, respectively (all comparisons, p less than 0.01). Digoxin concentration in the liver tissue was calculated and found to be appreciably elevated in the presence of quinidine. A reduction of about 30% (p less than 0.05) in the excretion of quinidine in the bile was observed in the presence of digoxin. Thus, a competition of digoxin and quinidine for biliary excretion was demonstrated as an underlying cause for digoxin-quinidine interaction in the isolated perfused rat liver.

The formation of genotoxic metabolites of benzo[a]pyrene by the isolated perfused rat liver, as detected by the bioluminescence test.

The kinetics of the formation of mutagenic metabolites of benzo[a]pyrene (BP) in an isolated perfused rat-liver system have been studied. No genotoxic activity was detected in the perfusate using either the Ames test or the new bioluminescence test for genotoxic agents (BLT). The bile excretion showed strong genotoxic activity especially in the presence of the deconjugation enzymes beta-glucuronidase and arylsulfatase. The BLT was 1000-fold more sensitive than the Ames test in detecting the genotoxic activity in the bile excretion.

Methylenetetrahydrofolate reductase deficiency: importance of early diagnosis.

Methylenetetrahydrofolate reductase deficiency is the most common inborn error of folate metabolism and should be suspected when homocystinuria is combined with hypomethioninemia. The main clinical findings are neurologic signs such as severe developmental delay, marked hypotonia, seizures, microcephaly, apnea, and coma. Most patients present in early life. The infantile form is severe, with rapid deterioration leading to death usually within 1 year. Treatment with betaine has been shown to be efficient in lowering homocysteine concentrations and returning methionine to normal, but the clinical response is variable. We report two brothers with methylenetetrahydrofolate reductase deficiency: the first was undiagnosed and died at 8 months of age from neurologic deterioration and apnea, while his brother, who was treated with betaine from the age of 4 months, is now 3 years old and has developmental delay.

Six-year follow-up of children with intrauterine growth retardation: long-term, prospective study.

This prospective study was designed to characterize the neurodevelopmental and cognitive difficulties specific to children with intrauterine growth retardation and to detect early clinical predictors of these difficulties. Eighty-one children with intrauterine growth retardation were monitored up to 6 to 7 years of age using biometric parameters, perinatal risk questionnaires, and detailed neurodevelopmental and cognitive assessments. Forty-one children served as age-matched, appropriate for gestational age controls. A significant difference in growth parameters (P < .001), neurodevelopmental score (P < .05), and IQ (P < .05) was found between the children with intrauterine growth retardation and controls. A specific profile of difficulties in coordination, lateralization, spatial and graphomotor skills, and abundance of associated movements is typical of the children with intrauterine growth retardation and hints at possible later learning disabilities. The clinical parameters best predicting neurodevelopmental outcome were the neonatal risk score (P < .05) and the weight and height at 6 years of age (P < .05). The children with intrauterine growth retardation with neonatal complications had lower neurodevelopmental scores than the controls but no difference in IQ. Intrauterine growth retardation children diagnosed prenatally had the same neurodevelopmental and IQ scores as those diagnosed at birth, probably due to the careful perinatal and obstetric care provided. Children with intrauterine growth retardation demonstrate a specific profile of neurodevelopmental disabilities at preschool age. Early diagnosis and intervention could probably reduce these difficulties to a minimum.

High-dose intravenous immunoglobulin in transient neonatal myasthenia gravis.

A preterm newborn had transient neonatal myasthenia gravis and was mechanically ventilated for 9 days. In addition to the usual supportive care, she was treated with neostigmine and underwent two exchange transfusions. High-dose intravenous immunoglobulin therapy (2 gm/kg) was used for the first time in transient neonatal myasthenia gravis to the best of our knowledge. The clinical and laboratory responses are presented.

Viral hepatitis during pregnancy in Israel.

Epidemiological, clinical and laboratory data were obtained relating to 89 pregnant women who suffered from viral hepatitis during the period 1967-1977 in Israel. The obstetrical data, course of labor and details about the newborn, were all compared with the accepted obstetrical standards in Israel and abroad. A follow-up study was made of the 89 women and 69 of the offspring from these pregnancies, covering a period of from 2 to 10 years. The data of the present study demonstrate that during the last decade, a period of generally rising socio-economic status in Israel, viral hepatitis in pregnant women, ran a more favorable course than that previously reported. The incidence of hepatitis is equal in all trimesters of pregnancy, and a favorable outcome may usually be anticipated for the mother and the newborn.

Blood pressure values in children with intrauterine growth retardation.

BACKGROUND: Low birth weight has been shown to be strongly related to hypertension in adult life. OBJECTIVES: To determine whether blood pressure is higher in children with intrauterine growth retardation than in control subjects. METHODS: Blood pressure was measured in 58 children aged 4-6 years with IUGR and in 58 age-matched controls. The control children, whose birth weight was appropriate for gestational age, were also matched for gestational age. RESULTS: The children with IUGR had significantly higher mean values of systolic (P < 0.05) and diastolic blood pressures (P < 0.05) and mean arterial pressure (P < 0.05). Significant differences in blood pressure values were found between preterm IUGR (n = 21) and preterm controls (P < 0.05). CONCLUSIONS: These data indicate that children with IUGR may be at higher risk of hypertension already in childhood.

The effect of intrauterine growth restriction on the development and health of children.

The neurodevelopmental and cognitive outcome of long-term Intrauterine Growth Restriction (IUGR) has been followed up from pregnancy to school age at the Tel Aviv Child Development Centre.

[Recurrent unilateral pulmonary edema due to left heart failure].

Unilateral pulmonary edema is uncommon and is usually associated with prolonged surgical procedures or rapid evacuation of a hydro- or pneumothorax. Unilateral pulmonary edema due to left heart failure in the absence of known lung disease is rare. It is therefore not readily recognized and is often confused with other unilateral alveolar or interstitial infiltrates. We describe 2 patients, a 69-year-old man and a 78-year-old woman, who had repeated episodes of unilateral pulmonary edema due to left heart failure. In both cases several other diagnoses were considered, but the cardiac origin of the infiltrates was supported by the rapid clearing of the lung after diuretic therapy. Awareness of this unusual clinical condition is important for the early institution of proper therapy.

[Heart-lung transplantation for idiopathic pulmonary fibrosis].

Diffuse idiopathic pulmonary fibrosis (DIPF) carries a poor prognosis, with an average survival of 4 years. A 37-year-old man had been followed by our department for over 5 years for biopsy-proven DIPF. The disease progressed relentlessly, unresponsive to corticosteroid or colchicine treatment. Marked pulmonary hypertension and right heart failure developed. Arterial pO2 decreased to 30 mmHg and he became bedridden and totally dependent on oxygen inhalation. A heart-lung transplantation was successful in June 1987. The anti-rejection regimen included cyclosporine and azathioprine. Subsequently his functional capacity improved remarkably and pO2 reached 87 mmHg on ambient air. Regular weekly followup visits have included physical examination, chest X-ray, cyclosporine blood levels, blood counts and determination of renal function. During a year of followup there has been no rejection episode nor any other major complication. Although experience with lung transplantation for end-stage DIPF is still limited, it is gradually being accepted as the only successful therapeutic approach. The case presented is the first in Israel of successful heart-lung transplantation for DIPF.