Subterahertz acoustical pumping of electronic charge in a resonant tunneling device.

We demonstrate that controlled subnanosecond bursts of electronic charge can be transferred through a resonant tunneling diode by successive picosecond acoustic pulses. The effect exploits the nonlinear current-voltage characteristics of the device and its asymmetric response to the compressive and tensile components of the strain pulse. This acoustoelectronic pump opens new possibilities for the control of quantum phenomena in nanostructures.

The efficient operation of the surgical pathology gross room.

The gross room is the area where pathology specimens from operating rooms are transferred for pathology review and analysis, serving as the bridge between the treating physician and diagnostic surgical pathologist. Reaching the correct diagnosis for a specimen depends on the proper handling and processing of tissue transferred to this very busy area. We review here the basic function and management of the gross room including a brief discussion of common specimen types, biohazard exposure and safety, and collection of tissue for research.

Acute challenge ERP as a prognostic of stimulant therapy outcome in attention-deficit hyperactivity disorder.

Thirty-five children were tested with an auditory oddball P300 paradigm both before and 2 hr after a single-dose trial of methylphenidate (MPH). A prediction of the long-term benefit of medication was then made based on the magnitude of the acute changes in P3b amplitude. Those with postdrug amplitude increases of at least 30% were predicted to respond favorably to stimulants. All children were followed-up at 6 months. The original MPH Challenge Test predictions (based on acute post drug P3b amplitude changes) were then compared with the clinicians' evaluations of outcome. The MPH challenge classification accurately predicted outcome in 81% of cases.

Methemoglobin levels during prolonged combined nitroglycerin and sodium nitroprusside infusions in infants after cardiac surgery.

Nitroglycerin (NTG) and sodium nitroprusside (SNP) are routinely used perioperatively in infants with congenital heart defects. In this study, NTG and SNP were infused in the operating room to increase venous capacitance, reduce systemic and pulmonary afterload, facilitate weaning off cardiopulmonary bypass, stabilize hemodynamics for transport to the intensive care unit (ICU), and reduce the fluid resuscitation needed upon arrival in the ICU. Because of the risk for accumulation of methemoglobin (MetHb) and cyanmethemoglobin (cyan-MetHb) during prolonged continuous infusion of NTG and SNP, it was decided to (1) quantify ICU use, (2) measure % MetHb at 12-hour intervals, and (3) look indirectly for the accumulation of cyan-MetHb by comparing simultaneous pulse oximetry (SpO2) (Nellcor N-100 [Nellcor, Haywood, CO]) and CO-oximetry (SaO2) (Corning 270 [Corning, Medfield, MA]). A total of 69 arterial samples were obtained from 16 infants (median age 4.4 months) following cardiac surgery with bypass. Median doses of NTG, 6.0 mg/kg (range 0.7 to 27.5), and SNP, 3.3 mg/kg (range 0.6 to 33.4), were infused over a median of 64.5 hours (range 12 to 183) (N = 16 patients). The median MetHb was 0.6% (range 0.0 to 1.5) after infusions of NTG, 1.8 micrograms/kg/min (range 0.5 to 4), and SNP, 1.3 micrograms/kg/min (range 0.3 to 8.4) (N = 69 measurements). Regression analysis of oximetry data yielded the equation: SpO2 = 1.04 SaO2 - 3.7%, r = 0.97. The mean difference between SpO2 and SaO2 data pairs was 0.0% (bias) with a SD (precision) of +/- 2.3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Power spectral EEG analysis and EEG variability in obsessive-compulsive disorder.

Spectral EEG characteristics of thirteen patients with severe Obsessive-Compulsive Disorder (OCD) were investigated topographically. The finding of predominantly left posterior frontal to mid-temporal theta-2 is discussed in light of previous EEG studies and recent neuroradiologic findings.

Shock induces a long-lasting elevation of blood glucose in Aplysia.

Glucose, and not trehalose, was found to be the main blood sugar in Aplysia californica. Changes in blood glucose in response to stress produced by electric shock were measured in blood obtained both from animals dissected within ten minutes of shocking and from catheterized animals at various intervals, up to two and a half hours after the shock. Electric shock increased blood glucose levels. The rise in blood sugar continued as long as two and a half hours after shock.

Stridor: intracranial pathology causing postextubation vocal cord paralysis.

During an 18-month period in a pediatric intensive care unit, nine patients with vocal cord paralysis were identified using flexible bronchoscopy. When tracheally extubated, each child was found to have stridor. The children ranged in age from 17 days to 5 1/2 years. Two patients had unilateral paralysis, but neither required tracheostomy. Seven patients displayed bilateral abductor vocal cord paralysis. Of these, six patients required tracheostomy. Surgical injury to the recurrent laryngeal nerve was the probable cause in two patients. The other seven patients had neurologic disorders with documented or suspected increases of intracranial pressure. Four of the seven patients with bilateral abductor vocal cord paralysis regained cord mobility within 4 months. Both children with unilateral cord paralysis have no stridor and vocalize well 1 year later. Cord paralysis in the setting of intracranial hypertension probably results from compression or ischemia of the vagus nerve before it exits the skull. Early visualization of the larynx should be done in patients who become stridulous when extubated, especially those with prior thoracic procedures or with neurologic disorders associated with intracranial hypertension.

High levels of polysaccharides in Aplysia hepatopancreas and penis: differential effects of nutrition and development.

1. Carbohydrate levels in tissues of Aplysia californica were measured. In animals maintained in the laboratory without feeding for 1-2 weeks, the penis contained the highest concentration of glycogen. 2. Blood glucose ranged between 2.5 and 4.8 mg/dl and averaged 3.2 +/- 0.2 mg/dl. 3. Fed animals had significantly greater tissue glycogen levels than starved animals. The penis exhibited the smallest per cent increase in glycogen concentration in response to feeding. 4. In contrast, the hepatopancreas exhibited a large increase, attaining glycogen concentrations near that of the penis. 5. Most of the increase in total tissue glycogen in fed animals occurred in the hepatopancreas. 6. Starved and fed animals did not differ significantly in blood glucose concentration, thus indicating that blood glucose is regulated and excess glucose is stored. 7. The hepatopancreas is the major mobile glucose store. 8. The high concentrations of glycogen found in the penis were not affected by mating activity. 9. However, penis glycogen concentration increased greatly with reproductive maturation of Aplysia; in contrast, hepatopancreas glycogen concentration was relatively unaffected by development. 10. A structural role by carbohydrates in the penis is suggested.

Trending of impedance-monitored cardiac variables: method and statistical power analysis of 100 control studies in a pediatric intensive care unit.

The NCCOM3-R6 monitor continuously monitors cardiac output and five other cardiovascular variables from the thoracic electrical bioimpedance signal. We averaged data over 5-min intervals for 130 min in 100 control studies in 40 pediatric ICU patients, age 0.04 to 20.39 yr (median 1.39) and weighing 2.0 to 59.5 kg (median 8.8). For individual studies, 99% of the 5-min averages of cardiac output fell within +/- 44% of the baseline cardiac output for that study. Normal ranges were somewhat narrower for the other five variables. When we averaged data for 100 studies, 5-min interval observations for each variable did not deviate from baseline over a 2-h period (p greater than .70). With a sample size of 100 studies, we could detect a change in cardiac output of +/- 5% at the p less than .005 level with a power of 0.95. We conclude that with a sufficiently large sample size, studies employing the NCCOM3 can detect clinically significant cardiovascular changes due to pharmacologic or procedural stressors.

Improved oxygenation and lower peak airway pressure in severe adult respiratory distress syndrome. Treatment with inverse ratio ventilation.

Two patients with the adult respiratory distress syndrome (ARDS) were placed on pressure-controlled inverse-ratio ventilation (IRV) when their condition deteriorated despite optimal treatment with intermittent mandatory ventilation and positive end-expiratory pressure. In the first case, high peak airway pressure was reduced by 50 percent with the institution of IRV. In the second, refractory hypoxemia was eliminated by using an inspiratory-to-expiratory ratio of 4:1. These cases show that IRV may offer certain advantages in the treatment of severe ARDS.