Enhanced proton acceleration by an ultrashort laser interaction with structured dynamic plasma targets.

We experimentally demonstrate a notably enhanced acceleration of protons to high energy by relatively modest ultrashort laser pulses and structured dynamical plasma targets. Realized by special deposition of snow targets on sapphire substrates and using carefully planned prepulses, high proton yields emitted in a narrow solid angle with energy above 21 MeV were detected from a 5 TW laser. Our simulations predict that using the proposed scheme protons can be accelerated to energies above 150 MeV by 100 TW laser systems.

Consensus on criteria for potential areas for wolf reintroduction in Mexico.

Given the conflict with human interests that in many cases results in the extirpation of large carnivores, acceptance of their reintroduction is a considerable challenge. By the 1980s Mexican wolves (Canis lupus) were extinct in the wild. In 1998 a population was reintroduced in the Blue Range Mountains of New Mexico (U.S.A.). Efforts to reintroduce the species in Mexico have been ongoing since the late 1980s. Four teams working independently identified 6 areas in northern Mexico in the historic range of Mexican wolves, where reintroductions could potentially be successful. Each team used different methods and criteria to identify the areas, which makes it difficult to prioritize among these areas. Therefore, members of the different teams worked together to devise criteria for use in identifying priority areas. They identified areas with high, intermediate, and low potential levels of conflict between wolves and humans. Areas with low potential conflict had larger buffers (i.e., distance from human settlement to areas suitable for wolves) around human settlements than high- and intermediate-conflict areas and thus were thought most appropriate for the first reintroduction. High-conflict areas contained habitat associated with wolf presence, but were closer to human activity. The first reintroduction of Mexican wolves to Mexico occurred in October 2011 in one of the identified low-conflict areas. The identification of suitable areas for reintroduction represents a crucial step in the process toward the restoration of large carnivores. Choice of the first reintroduction area can determine whether the reintroduction is successful or fails. A failure may preclude future reintroduction efforts in a region or country.

Pulmonary embolism following successful thrombectomy of an arteriovenous dialysis fistula.

A hemodialysis patient was diagnosed with pulmonary embolism, shortly after successful thrombectomy of an autogenous arteriovenous fistula. Diagnostic testing revealed no alternative source for thromboembolism. Increased recognition of hypercoagulability as a common consequence of end-stage renal disease would suggest that dialysis patients would be at risk for thromboembolic events. A fully developed dialysis fistula may have sufficient luminal diameter to harbor subclinical or clinically significant venous thrombi. Clinicians should be alert to the possibility of venous emboli after fistula manipulation.

Correlation of transcutaneous hepatic near-infrared spectroscopy readings with liver surface readings and perfusion parameters in a piglet endotoxemic shock model.

PURPOSE: To determine whether transcutaneous liver near-infrared spectrophotometry (NIRS) measurements correlate with NIRS measurements taken directly from the liver surface, and invasive blood flow measurements. PROCEDURE: Laparotomy was performed in 12 Yorkshire piglets, and ultrasound blood flow probes were placed on the hepatic artery and portal vein. Intravascular catheters were inserted into the hepatic and portal veins for intermittent blood sampling, and a pulmonary artery catheter was inserted via the jugular vein for cardiac output measurements. NIRS optodes were placed on skin overlying the liver and directly across the right hepatic lobe. Endotoxemic shock was induced by continuous infusion of Escherichia coli lipopolysaccharide O55:B5. Pearson's correlations were calculated between the NIRS readings and the perfusion parameters. FINDINGS: After endotoxemic shock induction, liver blood flow, and oxygen delivery decreased significantly. There were statistically significant correlations between the transcutaneous and liver-surface NIRS readings for oxyhemoglobin, deoxyhemoglobin, and cytochrome c oxidase concentrations. There were similar significant correlations of the transcutaneous oxyhemoglobin with both the mixed venous and hepatic vein saturation, and mixed venous and hepatic vein lactate. CONCLUSIONS: Transcutaneous NIRS readings of the liver, in an endotoxemic shock model, correlate with NIRS readings taking directly from the liver surface, as well as with global and specific organ-perfusion parameters.

Blood transfusion practice indicated by paediatric intensive care specialists in response to four clinical scenarios.

OBJECTIVE: Several clinical guidelines exist for blood transfusion in adults but only one refers to children. There are no guidelines for blood transfusion in critically ill children and the paediatric intensive care specialist's approach is unknown. We wished to evaluate the approach toward blood transfusion among a group of paediatric intensive care specialists. METHODS: All certified paediatric intensive care specialists from the Israeli society of pediatric intensive care medicine were requested to complete a questionnaire, which described four hypothetical common scenarios in paediatric intensive care units. In each case, the physicians were asked to denote the haemoglobin threshold at which they would prescribe a blood transfusion and the transfusion volume they would use. The specialists were also asked for their reasons for increasing their haemoglobin threshold for blood transfusion. RESULTS: The questionnaire was posted to twenty six paediatric intensive care specialists, twenty one of whom responded (i.e. 80.8%). There was a wide variation for each scenario in both the suggested haemoglobin thresholds for transfusion (varying by 20-50 g/L) and the transfusion volume (varying by 10-20 mL/kg). The reasons given for increasing their blood transfusion threshold included, in order of importance, shock, haemodynamic instability and hypoxaemia. CONCLUSIONS: There is a marked variability among paediatric intensive care specialists regarding both the threshold haemoglobin level at which blood transfusion is prescribed as well as the volume used.

Benign occipital epilepsy mimicking a catastrophic intracranial event.

OBJECTIVE: To describe the rare, dramatic, presentation of benign occipital epilepsy. METHODS: We describe three children who presented to the pediatric emergency department from 1992 to 1996 with a clinical picture of catastrophic intracranial event. RESULTS: The main signs and symptoms were loss of consciousness in all patients, apnea in two, hemiclonus in two, general hypertonicity in two, eye deviation in two, fixed dilated pupils in one, and decorticate rigidity in two. All underwent emergency intubation, brain scan, and lumbar puncture, and all were treated with antibiotics, in addition to antiviral drugs in two. Two patients were also treated for suspected increased intracranial pressure. Two patients recovered within a few hours and one within 24 hours of admission without any residual neurologic deficit. Electroencephalograms, done within 48 hours after the event, revealed the classic pattern of occipital epilepsy in two patients and bilateral occipital slow wave in one. A 3- to 5-year clinical and electroencephalographic follow-up supported the diagnosis. CONCLUSION: Benign occipital epilepsy in children can mimic a catastrophic intracranial event. Electroencephalography, performed early in the Pediatric Intensive Care Unit, may avoid or shorten unnecessary and aggressive treatments such as hyperventilation, diuretic agents, and prolonged antiviral therapy.

Acute diaphragmatic paralysis caused by chest-tube trauma to phrenic nerve.

A 3 1/2-year-old child developed unilateral diaphragmatic paralysis after chest drain insertion. Plain chest X-ray demonstrated paravertebral positioning of the chest-tube tip, and magnetic resonance imaging revealed hematomas in the region of the chest-tube tip and the phrenic nerve fibers. The trauma to the phrenic nerve was apparently secondary to malposition of the chest tube. This is a rare complication and has been reported mainly in neonates. Radiologists should notify the treating physicians that the correct position of a chest drain tip is at least 2 cm distant from the vertebrae.

Yield of bronchoalveolar lavage in ventilated and non-ventilated children after bone marrow transplantation.

A study was undertaken to retrospectively evaluate the yield of bronchoalveolar lavage (BAL) in a single-institution series of children after bone marrow transplantation (BMT) and to compare the yield of BAL between the ventilated and nonventilated patients. We reviewed charts of 52 consecutive children after BMT who underwent BAL. Thirty patients (41 BALs) were nonventilated (group 1) and 33 patients (45 BALs) were ventilated for respiratory failure (group 2). Eleven patients were included in both groups. BAL was performed a median of 255 and 28.5 days after BMT in groups 1 and 2, respectively (P < 0.001). Group 1:17 pathogens were isolated from 13 BALs; a single pathogen from 10 BALs. Group 2:15 pathogens were isolated from 14 BALs (31.1% positive). Viruses were isolated from 13 BALs in group 2. A severe complication of BAL occurred in only one patient from group 1 (1.1%). Open lung biopsies were performed in one patient in group 1 and eight patients in group 2. The histological findings correlated with the BAL findings in 66.7%. In conclusion, there was no difference in the yield of BAL between the groups. Therapy was changed in one third of the patients dictated by the BAL findings. The risk of severe complications was relatively low. A good correlation between open lung biopsy (OLB) and BAL was found.

Hemophagocytic lymphohistiocytic syndrome: Unrecognized cause of multiple organ failure.

OBJECTIVE: To describe an often-unrecognized clinical picture of multiple organ failure in hemophagocytic lymphohistiocytic syndrome (HLS). DESIGN: Retrospective chart review. SETTING: A ten-bed pediatric intensive care unit (PICU) in a tertiary children's university hospital. PATIENTS: A total of 11 children (age, 5 months to 13 yrs) who fulfilled the criteria for the diagnosis of familial- or infectious-associated hemophagocytic lymphohistiocytosis and who required intensive care support for organ failure. INTERVENTION: None. MAIN RESULTS: During a 10-yr period, 5,439 children were hospitalized in our PICU. A total of 11 children were diagnosed as suffering with HLS. Of these 11 patients, three (27%) had the familial form and eight had the infectious-associated form. After admission to the PICU, seven patients (63%) were diagnosed as suffering with HLS and each had one or more organ failures (patients 3-7, 9, and 10). All presented with fever, hepatomegaly, and splenomegaly; in addition, all had at least two of the following: anemia, neutropenia, or thrombocytopenia. All 11 had lymphohistiocytic accumulation in bone marrow (n = 10), lymph node (n = 2), lung (n = 2), and/or liver (n = 1). Organ failure was noted most often in the respiratory system (n = 7) attributable to severe, acute respiratory distress syndrome and pleural effusion. Of the 11 patients, six had cardiovascular involvement that manifested as shock in three and as capillary leak syndrome in three. Renal failure occurred in four patients. Of these, two required hemodiafiltration and one required peritoneal dialysis. Liver failure occurred in three and central nervous system involvement and coma in three. Most of the patients required massive therapeutic intervention, including assisted ventilation (n = 6), inotropic support (n = 3), and hemofiltration (n = 3). A total of seven patients (63%) died. CONCLUSIONS: Hemophagocytic lymphohistiocytic syndrome in the pediatric population may have a dramatic clinical picture, with multiple organ failure as a presenting symptom or early in the disease course, mandating intensive support in the PICU.

A comparison between continuous central venous pressure measurement from right atrium and abdominal vena cava or common iliac vein.

OBJECTIVE: To determine the accuracy of mean continuous central venous pressure (CVP) measurements in the abdominal vena cava. DESIGN: We simultaneously measured the CVP at the superior vena cava or right atrium and at the abdominal vena cava or common iliac vein. The study was conducted at the pediatric intensive care unit of a major university-affiliated medical center. PATIENTS: Nine patients, aged 6 months to 14 years, were included in our study. MEASUREMENTS AND RESULTS: Eleven continuous recordings of 12 to 68 min were taken, eight of them while the children were mechanically ventilated. Mean overall CVP ranged from 3 to 30 mmHg. A total of 519 simultaneous recordings were made, of which 515 (99.2%) were within the accepted limits of agreement of +/- 2 mmHg: 301 (58%) with delta CVP of +/- 0 mmHg, 189 (36,4%) with delta CVP of +/- 1 mmHg, and 25 (4.8%) with delta CVP of +/- 2 mmHg. The mean pressure difference was -0.22 +/- 1.52 mmHg. Accuracy was maintained within all ranges of CVP (3-10, 11-20, and 21-30 mmHg) and was not influenced by mechanical ventilation or abdominal fluid collection. CONCLUSION: In children with no obstruction of blood flow from the abdominal vena cava to the right atrium, the pressure in the abdominal vena cava or common iliac vein accurately reflects the pressure in the right atrium.

The immune response to booster vaccination against diphtheria toxin at age 18-21 years.

The purpose of this study was to evaluate the immunity of Israeli adults against the diphtheria toxin and to assess the immune response to a 2 Lf booster vaccination of diphtheria. The antibody levels against the toxin were measured in 200 volunteers aged 18-21. Later, a booster vaccination at a dosage of 2 Lf (flocculation units) was given and the immune response measured. We found that prior to the booster vaccination 174 (87%) of the study group had an antibody level > or = 0.1 IU/ml, 16 (8%) had an antibody level of > or = 0.06 IU/ml and < or = 0.09 IU/ml, and 10 (5%) had an antibody level of < or = 0.05 IU/ml. At the 10th day after the booster vaccination 185 (99%) acquired antibody level > or = 0.1 IU/ml, and at the 28th day all the vaccinees had antibody level above 0.1 IU/ml. When comparing the anamnestic and the delayed reaction to the booster vaccination, no significant difference was found between the group that prior to the vaccination had antibody level < or = 0.05 IU/ml and the group with antibody level > or = 0.06 IU/ml and < or = 0.09 IU/ml. Side effects were mainly local: 76 (38%) of the vaccinees had moderate local pain at the site of the injection and 40 (20%) had severe local pain. Abduction limitation of the injected arm was reported by 17 (8%) of the subjects. Weakness was reported by 67 (33%), headache by 18 (9%) and fever by 2 (1%) subjects. We conclude that antibody levels > or = 0.1 IU/ml are protective and booster vaccination at a dosage of 2 Lf raises the antibody levels to protective levels in all the vaccines.

Ranitidine-induced bradycardia in a neonate--a first report.

Bradycardia, an extremely rare side-effect of ranitidine therapy is described in a 4-day-old full-term male neonate, who was admitted because of massive gastro-intestinal bleeding. Two hours after the intravenous injection of 1 mg/kg body weight per day, ECG showed sinus bradycardia of 60 beats/min with normal axis and QRS complex. The bradycardia gradually resolved in the next 24 h.