Astronomy. ASASSN-15lh: A highly super-luminous supernova.

We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu ,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10(45) ergs s(-1), which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10(52) ergs, challenging the magnetar model for its engine.

Breathing pattern, CO2 elimination and the absence of exhaled NO in freely diving Weddell seals.

UNLABELLED: Weddell seals undergo lung collapse during dives below 50 m depth. In order to explore the physiological mechanisms contributing to restoring lung volume and gas exchange after surfacing, we studied ventilatory parameters in three Weddell seals between dives from an isolated ice hole on McMurdo Sound, Antarctica. METHODS: Lung volumes and CO(2) elimination were investigated using a pneumotachograph, infrared gas analysis, and nitrogen washout. Thoracic circumference was determined with a strain gauge. Exhaled nitric oxide was measured using chemiluminescence. RESULTS: Breathing of Weddell seals was characterized by an apneustic pattern with end-inspiratory pauses with functional residual capacity at the end of inspiration. Respiratory flow rate and tidal volume peaked within the first 3 min after surfacing. Lung volume reductions before and increases after diving were approximately 20% of the lung volume at rest. Thoracic circumference changed by less than 2% during diving. The excess CO(2) eliminated after dives correlated closely with the duration of the preceding dive. Nitric oxide was not present in the expired gas. CONCLUSION: Our data suggest that most of the changes in lung volume during diving result from compression and decompression of the gas remaining in the respiratory tract. Cranial shifts of the diaphragm and translocation of blood into the thorax rather than a reduction of thoracic circumference appear to compensate for lung collapse. The time to normalise gas exchange after surfacing was mainly determined by the accumulation of CO(2) during the dive. These findings underline the remarkable adaptations of the Weddell seal for restoring lung volume and gas exchange after diving.

Serum brain-derived neurotrophic factor is associated with reduced appetite in healthy older adults.

OBJECTIVE: Loss of appetite and body mass are common in older adults and are associated with negative consequences. Research indicates that these processes likely involve increases in serum brain-derived neurotrophic factor (BDNF). Animal and human models demonstrate that BDNF may serve a regulatory function in food intake, but no study has addressed the possibility that BDNF may be involved in appetite reduction and loss of body mass in older adults. DESIGN AND PARTICIPANTS: 34 older adults without significant neurological or psychiatric history underwent fasting blood draw and measurement of body composition. Appetite and eating behavior were assessed by questionnaire and related to serum BDNF levels. RESULTS: Partial correlations showed serum BDNF levels were inversely related to appetite (r = -.38, p = .02). No significant correlations emerged between serum BDNF and age, diet, or body composition. CONCLUSIONS: The current study extends past work and shows that BDNF is associated with appetite in healthy older adults. Further work is needed to clarify mechanisms for these findings, particularly prospective studies.

Release of lead from bone in pregnancy and lactation.

Concentrations and isotope ratios of lead in blood, urine, 24-h duplicate diets, and hand wipes were measured for 12 women from the second trimester of pregnancy until at least 8 months after delivery. Six bottle fed and six breast fed their infants. One bottle feeder fell pregnant for a second time, as did a breast feeder, and each was followed semicontinuously for totals of 44 and 54 months, respectively. Bone resorption rather than dietary absorption controls changes in blood lead, but in pregnancy the resorption of trabecular and cortical bone are decoupled. In early pregnancy, only trabecular bone (presumably of low lead content) is resorbed, causing blood leads to fall more than expected from hemodilution alone. In late pregnancy, the sites of resorption move to cortical bone of higher lead content and blood leads rise. In bottle feeders, the cortical bone contribution ceases immediately after delivery, but any tendency for blood leads to fall may be compensated by the effect of hemoconcentration produced by the postpartum loss of plasma volume. In lactation, the whole skeleton undergoes resorption and the blood leads of nursing mothers continue to rise, reaching a maximum 6-8 months after delivery. Blood leads fall from pregnancy to pregnancy, implying that the greatest risk of lead toxicity lies with first pregnancies.

[Progressive encephalopathies in children]. / Encefalopatie postepujace u dzieci.

The Authors describe progressive encephalopathies in children hospitalized at the Department of Child Neurology Silesian Medical School from 1980 to 2000. They present ethiology, clinical symptoms and diagnostic protocol based on literature data and their own experience.

Effect of restoration of AV synchrony on stroke volume, exercise capacity, and quality-of-life: can we predict the beneficial effect of a pacemaker upgrade?

The aim of this study was to assess to what extent patients with VVIR pacemakers and without overt symptoms of a pacemaker syndrome benefit from a pacemaker upgrade, and if a preoperative noninvasive measurement of the change in stroke volume (SV) could predict the effect of a pacemaker upgrade. The study group consisted of 20 (12 women, 8 men) VVIR patients with a mean age of 60 years. The indication for the first implantation was AV block in 13 patients and SSS in 7. The mean time of a ventricular pacing was 77 months. The objective (echocardiography, an exercise capacity) and the subjective (the quality-of-life) parameters investigated in patients during ventricular pacing were compared to results obtained 2 months and 1 year after a pacemaker upgrade. To assess preoperatively a change in a SV expected after upgrading, attempts were made to restore AV synchronization by the use of a transesophageal pacemaker. An increase in SV (from 5% to > 35%) during temporary AV resynchronization was observed in each patient. Values of SV increase correlated with those obtained 2 months (r = 0.65; P < 0.01) and 1 year (r = 0.66; P < 0.01) after an upgrade. Superior hemodynamics was associated with a significant improvement of an exercise capacity in both subgroups of patients. The most significant improvement in the quality-of-life was observed in patients with SSS. We did not find correlations between SV and the quality-of-life assessed 2 months (r = 0.043; NS) or 1 year (r = 0.02; NS) after an upgrade. In conclusion, a pacemaker upgrade performed after a long-term ventricular pacing resulted almost consistently in the improvement of hemodynamics and was associated with an increase of exercise capacity. In patients with SSS it was followed by the significant improvement of their quality-of-life. Such a relation was not observed in patients with AV block as some of them (especially those with VVIR pacemakers) felt quite well during ventricular pacing. The proposed preoperative echocardiographic evaluation may precisely predict the degree of hemodynamic improvement expected after a pacemaker upgrade.

[Cerebral tumors as a cause of refractory epilepsy in children]. / Procesy rozrostowe wewnatrzczaszkowe jako przyczyna padaczki lekoopornej u dzieci.

Cerebral tumours are a cause of seizures in less than 1-2% of children epilepsy. Seizure symptoms usually precede the diagnosis by several years and are often the only symptoms of an ongoing process. The symptomatology of the seizures often correlates with localization of a neoplastic lesion. The authors present six children aged 3 to 18 in whom epileptic seizures not susceptible to treatment were caused by cerebral tumours. The duration of epilepsy until the determining of the aetiology was various--from half a year to 13 years. In each of our six patients focal epilepsy occurred with simple or complex seizures with secondary generalization. It was only one patient in whom the tomography of the head turned out to be sufficient enough to establish the diagnosis of a brain tumour; in the other ones MR was necessary. The final diagnosis in four of the children was supported by histopathologic examination carried out during a neurosurgical procedure, whereas in one of them--by means of biopsy of the brain.

Acquisition and retention of lead by young children.

The concentrations and isotope ratios of lead in blood and urine, on the hands, and in duplicate diet samples were measured for children living in Omaha, Nebraska. One group consisted of 22 children followed from birth to between 1 and 2 years of age and another group was 20 2- to 4-year-old children followed for 1 year, although some in each group were followed for periods between 3 and 4 years. At no time in life was a component of dietary lead identified in blood by isotope ratios, and blood lead appears dominated by lead derived from the hands, which in turn appears derived from the floors. For some homes floor lead appeared to be a mixture of lead from window sills and from the exterior. Only 2 of the children appear to have ingested lead directly from window sills. Several who lived in homes being remodeled were exposed to lead before the age of 2 years. For those who had been briefly exposed during professional remodeling the blood lead fell with a half-life of 10 months but for those who had suffered prolonged exposure during remodeling by parents the apparent half-life was longer, between 20 and 38 months.

[Munchausen's syndrome by proxy--a malignant form of child abuse]. / Zespól Munchhausena per proxy--szczególna forma maltretowanego dziecka.

Munchhausen syndrome by proxy is a malignant form of child abuse in which illness in a child is fabricated and/or induced by a parent. It can result in serious illness and even death of the child and it is difficult to detect. The authors give a significant amount of literature examples. They try to find out the difference in ways of hurting by perpetrators. Various types of personalities and emotional disturbances in Munchhausen on proxy syndrome are shown. Child maltreatment and Munchhausen by proxy syndrome need to be part of the differential diagnosis when the clinical picture is atypical or does not appear medically plausible.

[Huntington chorea in a boy aged 14 years]. / Plasawica Huntingtona u 14-letniego chlopca.

The authors present a case of Huntington disease in a 14 year old boy. The basis of genetic, pathoetiology, clinical course of disease, significance of molecular analysis of DNA are discussed.

Validity of bioelectrical impedance analysis to measure body fat in Air Force members.

This study determined if the bioelectrical impedance analysis (BIA) method was a more valid assessment of body fat in Air Force members than the current Air Force circumference (AF) method. Both methods were compared with hydrostatic weighing, which is the presumed standard for identifying body fat. Subjects included 50 male and 50 female active duty Air Force members between the ages of 19 and 47 years. The AF method had higher correlation coefficients and lower standard error of estimates for both male and female subjects (r = 0.91 [3.00%] and r = 0.79 [3.28%], respectively) than the BIA method (r = 0.84 [3.25%] and r = 0.75 [4.30%], respectively). The false-positive rates for individuals having excess body fat were greater for the AF method (14.7 and 29.3% for males and females, respectively) than the BIA method (7.3 and 8.8% for males and females, respectively). The data suggest that caution should be used when the current AF method or the BIA method is used to make individual Air Force career decisions.

[Lyme disease in children]. / Borelioza u dzieci.

In the recent years the number of diagnosed cases of Lyme Disease has tended to increase. This is due to the possibility of serological examinations. Between 1992-95 at the Neurological Department of 2nd Chair of Pediatrics Silesian Medical Academy in Katowice 7 children with Lyme Disease were hospitalized. The authors analysed the clinical course, important laboratory and serological data and treatment effects.

Motion perimetry in anisometropic amblyopia: elevated size thresholds extend into the midperiphery.

PURPOSE: Our purpose was to determine whether motion detection abnormalities in patients with anisometropic amblyopia exist and to determine the extent of these abnormalities in the central and midperipheral visual field. METHODS: We used of motion perimetry to evaluated 10 anisometropic subjects with no manifest strabismus. Each of 44 locations in the visual field corresponding to the test sites of the Humphrey 24-2 program was tested with circular patches of motion (random dot cinematograms) displayed on a computer screen. Stimulus patch size was reduced in a 2/1 staircase manner to determine the smallest patch of motion detectable at each test location (threshold). Data from 15 age-matched normal subjects were used as controls. RESULTS: Vision in the amblyopic eye ranged from 20/25 to count fingers. The overall mean size threshold for amblyopic eyes was elevated (61% +/- 73%) compared with fellow eyes and age-matched normal eyes (p < 0.03) (i.e., the moving patch of dots in the field had to be larger for it to be detected when viewing with the amblyopic eye). The increase in size threshold was consistent across the visual field and was not greater for central locations. CONCLUSION: The amblyopia caused by anisometropia is associated with an abnormality in motion detection that extends into the midperiphery of the visual field.

Lead consumption of 18- to 36-month-old children as determined from duplicate diet collections: nutrient intakes, blood lead levels, and effects on growth.

OBJECTIVE: To determine the amount of lead ingested in food by means of duplicate diet collections, nutrient intakes, and anthropometric measurements of young children. DESIGN: Once a month for a year, data were collected from 24-hour duplicate diets, hand wipes, a dust index, and anthropometric measurements. Quarterly, venous blood samples were obtained. Thermal ionization spectrometry by means of a lead-205 tracer was used to determine lead present in food, blood, and the hand wipes. A dust index was determined on the basis of observation of dust on surfaces in the home. Anthropometric measurements obtained were height, weight, head circumference, and mid-upper arm circumference. SUBJECTS/SETTING: Subjects were 21 children, aged 18 to 36 months, who resided in homes located in an urban area with potentially high lead levels. MAIN OUTCOMES MEASURED: Lead contamination in food and on hands, and blood lead values, were determined. STATISTICAL ANALYSIS PERFORMED: Pearson correlation coefficients were used to determine relationships between lead content in food, blood, and hand wipes and growth. Multiple regression analyses examined the effect of food types and dust lead on lead levels in food, and the effect of these variables on head circumference. RESULTS: Mean blood levels were 0.3089 +/- 0.1496 micromol/L; 12 samples contained more than 0.4826 micromol/L. Total intake of lead from food was 4.95 microg/day and ranged from 1.10 to -22.10 microg/day. More than a fourth of the diets collected exceeded 6.00 microg/day. Foods considered home prepared were moderately related to blood lead level, and the dust index and hand wipe lead levels were related to total food lead. Home-handled foods, canned foods, and hand-wipe lead were significant predictors of the lead content in food. A negative relationship was found between head circumference and blood lead level. APPLICATIONS: Level of lead in food was directly related to hand-wipe lead. This finding underscores the need for dietitians and other health professionals to stress the importance of cleanliness in environments that are potentially lead contaminated. Appropriate hand washing and surface cleaning should be emphasized when preparing and consuming food. The inverse relationship between head circumference and blood lead levels points to the need for additional studies to validate this finding while controlling for other extraneous variables.

The psychometric function and reaction times of automated perimetry in normal and abnormal areas of the visual field in patients with glaucoma.

PURPOSE: To study the relationship of reaction time to the psychometric function in normal subjects, normal sensitivity test locations in patients with glaucoma, and test locations with 10 to 20 dB loss in patients with glaucoma. METHODS: The authors tested 10 patients with glaucoma and 10 age-matched normal volunteers with the Humphrey perimeter, first with program 24-2 and then with the method of constant stimuli to generate frequency of seeing curves. At two widely separated visual field locations on the program 24-2 grid, they presented stimuli in 2-dB intervals, 10 dB either side of the program 24-2 threshold, at 0 dB and 60 dB (15 repetitions per intensity). For the patients with glaucoma, they chose a visual field location with normal sensitivity and a location in an area of 10 to 20 dB loss. RESULTS: Analysis of variance with post hoc t-tests showed that reaction time (RT) at the 0-dB intensity was prolonged by approximately 90 msec in the abnormal sensitivity test location of patients with glaucoma compared to the control and the glaucoma normal sensitivity groups (P<0.0001). However, this difference was accounted for by only 4 of the 10 patients with glaucoma, reaching 100% of stimuli seen with the brightest stimulus at the moderately damaged test location. Reaction time at the frequency of seeing 50% estimated threshold showed no significant differences among the groups. Prolongation of RT from the 0-dB value was analyzed as a function of increasing attenuation of stimulus intensity. The results fit the equation RT = a + b(Intensity3) for all groups. CONCLUSIONS: There is no significant difference in RT between normal subjects and patients with glaucoma either at threshold or to suprathreshold stimuli. Reaction time increases after a power function with increasing attenuation of stimulus intensity up to the threshold.

Splenic contraction, catecholamine release, and blood volume redistribution during diving in the Weddell seal.

The spleen of the Weddell seal (Leptonychotes weddelli) may contract and inject red blood cells (RBCs) into the peripheral circulation during diving, but evidence for this hypothesis is indirect. Accordingly, we measured splenic dimensions by ultrasonography, plasma catecholamine concentrations, hemoglobin concentration, and hematocrit in five Weddell seals before and after intravenous epinephrine during halothane anesthesia and while awake at the surface after voluntary dives. Spleen size was reduced immediately after epinephrine injection or after the seal surfaced. Within the first 2 min after the seal surfaced, cephalocaudal splenic length was 71 +/- 2% (mean +/- SD; P < 0.05) and splenic thickness was 71 +/- 4% (P < 0.05) of the maximal resting values. Splenic size increased (half-time = 6-9 min) after the seal surfaced and was inversely correlated with plasma epinephrine and norepinephrine concentrations. Hemoglobin concentration increased from 17.5 +/- 5.3 g/dl (measured during general anesthesia) to 21.9 +/- 3.7 g/dl (measured in the first 2 min after surfacing). At these same times, the hematocrit increased from 44 +/- 12 to 55 +/- 8%. These values decreased (half-time = 12-16 min) after the seal surfaced. We estimate 20.1 liters of RBCs were sequestered at rest, presumably in the spleen, and released either on epinephrine injection or during diving. Catecholamine release and splenic contraction appear to be an integral part of the voluntary diving response of Weddell seals.

Hormonal regulatory adjustments during voluntary diving in Weddell seals.

Subadult male Weddell seals were instrumented with microcomputer-based backpacks and were then monitored during voluntary diving and recovery periods in McMurdo Sound, Antarctica. Depth and duration of diving, swim speed, and dive pattern were routinely monitored. An indwelling venous catheter was used to collect plasma samples at various time periods before and following diving episodes, so that changes in plasma concentrations of hormones and of metabolites could be measured. Adrenergic and nitroxidergic regulatory effects were assessed indirectly by measuring concentration changes in catecholamine and cyclic guanosine monophosphate (cGMP), respectively. The studies found that (i), except for dives of less than several minutes, epinephrine and norepinephrine both increased as a function of diving duration, then rapidly decreased during recovery (with a half time of about 10 min), (ii) that the changes in catecholamine concentrations correlated with splenic contraction and an increase in circulating red blood cell mass (hematocrit), (iii) that the changes in catecholamines, especially [epinephrine], were inversely related to insulin/glucagon ratios, which mediated a postdiving hyperglycemia, and (iv) that in long dives (but not short ones) the changes in catecholamines correlated with increasing reliance on anaerobic metabolism, indicated by increased plasma lactate concentrations. These diving-catecholamine relationships during voluntary diving at sea were similar to those observed during enforced submergence (simulated diving) under controlled laboratory conditions. At the end of diving, even while catecholamine concentrations were still high, many of the above effects were rapidly reversed and the reversal appeared to correlate with accelerated nitric oxide production, indirectly indicated by increased plasma cGMP concentrations. Taken together, the data led to the hypothesis of important adrenergic regulation of the diving response in seals, with rapid reversal at the end of diving and during recovery being regulated by nitroxidergic mechanisms.

Myoglobin saturation in free-diving Weddell seals.

Although the consumption of myoglobin-bound O2 (MbO2) stores in seal muscles has been demonstrated in seal muscles during laboratory simulations of diving, this may not be a feature of normal field diving in which measurements of heart rate and lactate production show marked differences from the profound diving response induced by forced immersion. To evaluate the consumption of muscle MbO2 stores during unrestrained diving, we developed a submersible dual-wavelength laser near-infrared spectrophotometer capable of measuring MbO2 saturation in swimming muscle. The probe was implanted on the surface of the latissimus dorsi of five subadult male Weddell seals (Leptonychotes weddelli) released into a captive breathing hole near Ross Island, Antarctica. Four seals had a monotonic decline of muscle O2 saturation during free diving to depths up to 300 m with median slopes of -5.12 +/- 4.37 and -2.54 +/- 1.95%/min for dives lasting < 17 and > 17 min, respectively. There was no correlation between the power consumed by swimming and the desaturation rate. Two seals had occasional partial muscle resaturations late in dives, indicating transfer of O2 from circulating blood to muscle myoglobin. Weddell seals partially consume their MbO2 stores during unrestrained free diving.

Stable isotope identification of lead sources in preschool children--the Omaha Study.

The objective was to determine, from analysis of the naturally occurring stable isotopes of lead, the relative contribution of food, handdust, housedust, soil and air lead to the absorbed (urinary) lead and the blood lead of children living in a former smelter city. A longitudinal 12 month study was conducted of 21 children, 2 - 3 years of age, living in central Omaha, balanced for race, gender and socioeconomic status. Field clean samples were collected monthly of 24 hour duplicate diet, handwipe and urine, with quarterly blood lead, annual environmental lead, weekly air for total lead and 206Pb, 207Pb and 208Pb by thermal ionization/mass spectrometry with a 205Pb spike in a Class II laboratory. Despite residence in a smelter city each child had a unique isotopic ratio of handwipe, blood and urine lead, the latter being identical. There was no correlation of handwipe isotopic ratio with proximity to a lead emission source or to the decade of the housing stock. The isotopic ratio of the annual mean handwipe lead predicted 43% of the variance of the annual mean blood and urine lead ratio (r2 = .43; p = .001). Handwipe lead ratios correlated (p < or = .05) with those of the windowsills and air ducts. The mean isotopic ratios of blood and urine lead were lower than those of handwipe and food, consistent with a contribution by endogenous bone lead. Clean catch urine provides a noninvasive index of blood lead isotopic ratio in children, as in adults.