Direct observation of depth-dependent atomic displacements associated with dislocations in gallium nitride.

We demonstrate that the aberration-corrected scanning transmission electron microscope has a sufficiently small depth of field to observe depth-dependent atomic displacements in a crystal. The depth-dependent displacements associated with the Eshelby twist of dislocations in GaN normal to the foil with a screw component of the Burgers vector are directly imaged. We show that these displacements are observed as a rotation of the lattice between images taken in a focal series. From the sense of the rotation, the sign of the screw component can be determined.

Evidence of PCDD/Fs and PCBs contamination in trees grown in forests far from their production and contamination-free areas.

Polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in trees grown in pathless forests were analyzed to investigate their dispersal patterns in the atmosphere. The pg/g levels of 23 PCCD, 22 PCDF, and 54 PCB congeners were identified. The total amount of PCDDs in the red pine tree sample (95.8 pg/g) was approximately 7 times that in the beech tree sample (13.2 pg/g). The total amount of PCDFs in the red pine tree sample (71.1 pg/g) was also approximately 7 times that in the beech tree sample (11.1 pg/g). The total amounts of PCBs in the red pine tree and beech tree samples were 1,380 and 1,150 pg/g, respectively. The (Cl1-Cl3)-PCBs comprised 63.1 % and 67.6 % of total PCBs in the red pine and in the beech, respectively. The results of the present study indicate that PCDD/Fs and PCBs are transferred over long distances in the atmosphere and accumulated in the contamination-free areas.

Risk assessment of recent Egyptian H5N1 influenza viruses.

Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype are enzootic in poultry populations in different parts of the world, and have caused numerous human infections in recent years, particularly in Egypt. However, no sustained human-to-human transmission of these viruses has yet been reported. We tested nine naturally occurring Egyptian H5N1 viruses (isolated in 2014-2015) in ferrets and found that three of them transmitted via respiratory droplets, causing a fatal infection in one of the exposed animals. All isolates were sensitive to neuraminidase inhibitors. However, these viruses were not transmitted via respiratory droplets in three additional transmission experiments in ferrets. Currently, we do not know if the efficiency of transmission is very low or if subtle differences in experimental parameters contributed to these inconsistent results. Nonetheless, our findings heighten concern regarding the pandemic potential of recent Egyptian H5N1 influenza viruses.

Blink reflex elicited by auditory stimulation in the rabbit.

The pathway of the blink reflex, elicited by auditory stimulation, was investigated electrophysiologically. The reflex was recorded as microvibrations of the eyelid and was named the auditory-evoked eyelid microvibration (AMV). Pharmacophysiological studies suggest that AMV is closely related to the midbrain reticular formation and studies of electrical lesions in the midbrain reticular formation support this. Lesions in several parts of the central nervous system provide evidence that the inferior colliculus has an important role in AMV, and the cerebral cortex may have an inhibitory influence. Studies of brainstem transections indicate that the reflex pathway of AMV exists between the lower midbrain and the upper medulla. Because of its ease and simplicity, AMV is believed to be a useful test for evaluation of the function of the brainstem.

Oscillatory potentials of visual evoked potentials using source derivation technique in rabbits.

The topographic distribution of epidurally recorded flashed visual evoked potentials (VEPs) in unanesthetized rabbits was studied using 2 montages. VEPs with linked ears reference and source derivation were compared. With the linked-ears reference, N34 of VEPs which consisted of slow potentials and superimposed oscillations were recorded diffusely over the head. When source derivation was used, the slow negative potentials of N34 present on the recordings in P3 and P4 were not obtained in F3, Fz and F4. In a digital filtering study of the oscillatory potentials, N34 in oscillatory potentials which were recorded diffusely over the head were localized to the visual cortex by source derivation. It was concluded that N34 in the oscillatory potentials generated from the visual cortex are enhanced and localized with source derivation.

Gas chromatographic-mass spectrometric determination of hydrophilic compounds in environmental water by solid-phase extraction with activated carbon fiber felt.

Simple gas chromatographic-mass spectrometric determination of hydrophilic organic compounds in environmental water was developed. A cartridge containing activated carbon fiber felt was made by way of trial and was evaluated for solid-phase extraction of the compounds in water. The hydrophilic compounds investigated were acrylamide, N,N-dimethylacetamide, N,N-dimethylformamide, 1,4-dioxane, furfural, furfuryl alcohol, N-nitrosodiethylamine and N-nitrosodimethylamine. Overall recoveries were good (80-100%) from groundwater and river water. The relative standard deviations ranged from 4.5 to 16% for the target compounds. The minimum detectable concentrations were 0.02 to 0.03 microg/l. This method was successfully applied to several river water samples.

Mutagenicity of 3-nitrodibenzofuran and 3-aminodibenzofuran.

Mutagenicities of 3-nitrodibenzofuran and 3-aminodibenzofuran were examined using Salmonella typhimurium TA98 and TA100. Strong mutagenicity was found in both compounds. The mutagenic potency of 3-nitrodibenzofuran was approximately 3.5-fold stronger in TA98 and twice stronger in TA100 than that of benzo[a]pyrene. Mutagenicity of 3-aminodibenzofuran was observed under metabolic activation and was 10 times stronger in TA98 and about 5 times stronger in TA100 than that of benzo[a]pyrene.

Photo-evoked eyelid microvibration in neonates with hyperosmolality.

We studied neonates with hyperosmolar syndrome using photo-evoked eyelid microvibration, a blink reflex elicited by photic stimuli. Patients with hyperosmolality showed disturbance of consciousness, convulsive seizures, hyperexcitability, and tachypnea. The latency of photo-evoked eyelid microvibration tended to be prolonged with an elevation of the plasma osmolality. Photo-evoked eyelid microvibration is believed to be a suitable method for monitoring brain disturbance due to hyperosmolality.

Music therapy for children with Rett syndrome.

The Rett syndrome is good reactivity for sound and music. We enforced active music therapy (MT) individual session to patients with Rett syndrome. The patients were 4, 5 and 6-year-old. The active music therapy and individual session of 30 min/week were performed. It was recorded in video and description, and using the original evaluation list, six items of fact. On largest problem that is hand operation with purpose in childhood of Rett syndrome, we recorded the longest duration and frequency of hand grasping time in one session. There was the improvement of 35.0% of listening music, 33.3% play music, 13.3% singing music, 11.7% minute motion, 11.7% language, and 20.0% personal relation and sociality. The longest duration of hand grasping time was improved from 2 to 12 s in case 2 and from 7 to 80 s in case 3. Grasp frequency which showed the volition rapidly increased from 3 to 41 times, though the elongation for the duration of grasping was little for case 2. Rett syndrome is the disease in which the psychomotor performance regresses with the age, but the aspect that surely developed in the session could be evaluated. Rett syndrome has the ability understanding the music, and music therapy is suitable for them.

Intracranial hemorrhage following administration of sodium bicarbonate in rabbits.

Studies on the correlation between hyperosmolality and brain damage, especially intracranial hemorrhage, were carried out on young and newborn rabbits following infusion with 7% sodium bicarbonate. 1) All the young rabbits injected with 7% sodium bicarbonate died of hyperosmolality at over 380 mOsm/L (the mean was 462 mOsm/L) after drip infusion at the rate of 20-60 ml/kg/hr. Young rabbits under a 10% hypoxic environment died even at the 350 mOsm/L level (the mean was 392 mOsm/L) during infusion of 7% sodium bicarbonate. Half of the case of newborn rabbits injected with 7% sodium bicarbonate at 10 ml/kg, intraperitoneally, had intracranial hemorrhage at 335 mOsm/L. When the hyperosmolality reached 392 mOsm/L (50 ml/kg), intracranial hemorrhage was observed in all cases. 2) The main cause of death in young and newborn rabbits was subdural hemorrhage in the subtentorial region. Intraventricular hemorrhage was observed in about 40% of the cases of young and newborn rabbits. 3) The blood pH was elevated by the drip infusion, but when the hyperosmolality reached about 400 mOsm/L, the blood pH began to fall. At the same osmolality, pCO2 showed a marked elevation. It is likely that the decrease of the blood pH was caused by the elevation of pCO2 and the outflow of H+ from intracellular compartments resulting from the hyperosmolality. These results apparently indicate that fatal intracranial hemorrhage was induced by hyperosmolality and was enhanced by the combination of hypoxia and immaturity.

Photo-evoked eyelid microvibration (blink reflex elicited by flash stimuli) in newborns and children.

The orbicularis oculi muscle contracts in response to photic stimulation. It was recorded as the microvibration of the eyelid contraction and it is called the photo-evoked eyelid microvibration (MV). MV was recorded using a special transducer on the central part of the upper eyelid from 167 subjects free of any neurological abnormalities. One G of the vibration was converted into 100 mV. The normal value was shown in newborns and children. The latency was 171.0 +/- 30.5 msec in newborns, 70.3 +/- 12.3 msec in 4 to 5 year-olds, 46.3 +/- 11.2 msec in 7 to 8 year-olds and 57.0 +/- 4.9 msec in adults. The latency of MV became shortened with growth. It is thought that the shortening of the latency during maturation is related to the myelination of the brainstem reticular formation and the maturation of the retina.

The effects of stimulus rates on the amplitude of median nerve somatosensory evoked potentials: the developmental change.

We examined the effects of stimulus rates on the somatosensory evoked potential (SEP) amplitudes following median nerve stimulation at the wrist in 42 children. We divided these subjects into five groups according to their age (0-6 months, 7-12 months, 1-3 years, 4-6 years and more than 7 years) and measured the peak-to-peak amplitude of every component (N9, P10, N11, P13/14, N18, N20, P23, N30) at stimulus rates of 1.0, 3.5 and 5.5 Hz. From N9 to N18, there was no significant change in amplitude nor latency with stimulus rate change in all groups. The amplitude attenuation was found at the N20 and N30 peaks in the young group (0 months to 3 years) and at P23 in all groups with an increasing stimulus rate. The attenuation rate of P23 amplitude was influenced by the age of subjects, being greater in younger groups and greatest in the youngest group (0-6 months). The differences of amplitude attenuation rate between this group and the rest were statistically significant. The results of this study indicate that the amplitudes of the cortical components of SEP in children are greatly influenced by the stimulus rate. Thus when we discuss the amplitude of cortical waves in childhood, we should also pay attention to the stimulus rates.

Auditory brainstem response in neonates--an attempt to reduce the number of stimuli.

We tried to shorten the ABR testing time by reducing the number of stimuli. There was no difference in both the wave form and latency of each wave between 256 times-averaged ABR and 1,024 times-averaged ABR. The total testing time, using 256 stimuli, was about 20 minutes shorter than the testing time using 1,024 stimuli.

Effects of hyperosmolality on the central nervous system and intracranial hemorrhage.

The relationship between hyperosmolality and intracranial hemorrhage as well as brain dysfunction was studied. Hyperosmolality was induced by continuous infusion of hyperosmotic solutions, such as 7% sodium bicarbonate (1,666 mOsm/1), 4.64% sodium chloride (1,666 mOsm/1), 20% glucose (about 1,200 mOsm/1), 20% mannitol (about 1,200 mOsm/1), and 10% glycerol with 0.9% sodium chloride and 5% fructose (about 2,000 mOsm/1). 1) Intracranial hemorrhage was observed without exception after the rabbits had died of hyperosmolality due to the infusion of these agents. The intracranial hemorrhage was mostly subdural hemorrhage in the subtentorial region. 2) The plasma osmolality just before death varied according to the agents administered and was lowest in the case of 7% sodium bicarbonate with a level of 441 mOsm/1. 3) The plasma osmolality in the case of 10% glycerol was higher than the case of 20% mannitol at the death. 4) The arousal reaction was suppressed by hyperosmotic solutions which contain sodium ions, and when the plasma osmolality surpassed 320 mOsm/1, dysfunction of the CNS began to appear. 5) The evoked muscular discharges caused by stimulation of the midbrain reticular formation were suppressed only by the administration of 7% sodium bicarbonate, so this result is related to alkalosis.

Prediction of the prognosis in neonatal asphyxia by photo-evoked eyelid microvibration.

Neonatal asphyxia causes hypoxic-ischemic encephalopathy and may damage the central nervous system. We studied neonatal asphyxia with photo-evoked eyelid microvibration (PEMV) which is a blink reflex elicited by photic stimuli. The latency of PEMV changed according to the severity of encephalopathy and the degree of unconsciousness. All of the neonate who had showed disappearance of PEMV died. When the prolonged latency persisted, the infant had a strong probability of sustaining neurological sequelae. PEMV provides useful information for predicting the outcome of neonatal asphyxia.

Serum and urinary carnitine and organic acids in Reye syndrome and Reye-like syndrome.

Free and acyl-carnitine in serum and urine, and urinary organic acids were measured in 6 patients with Reye syndrome and Reye-like syndrome. The free and total carnitine concentrations were significantly reduced in serum during the acute phases of the diseases. Thus, the ratio of acylcarnitine to free carnitine was significantly increased. Urinary excretion of acylcarnitine was greatly increased, and the acylcarnitine to total carnitine ratio was therefore greater than in controls. The urinary organic acids comprised large amounts of lactic acid, dicarboxylic acids and ketone bodies. It is suggested that carnitine deficiency is induced as more carnitine is consumed to buffer the increased amount of toxic acyl-CoA compounds metabolized from free fatty acids and the many organic acids. These results indicate that administration of L-carnitine should generally be considered in patients with Reye syndrome and Reye-like syndrome.

Successful control with bromide of two patients with malignant migrating partial seizures in infancy.

A 3-month-old male and a 4-month-old female infant with intractable seizures were diagnosed as having malignant migrating partial seizures in infancy (MMPSI) with developmental arrest on the basis of characteristics of symptoms, clinical courses and EEGs. We treated these two patients with potassium bromide (80 mg/kg) after conventional antiepileptic drugs failed to adequately control the seizures. The potassium bromide therapy resulted in complete control of seizures in one patient, and more than 95% reduction in seizure frequency in the other.

Reye-like syndrome associated with valproic acid.

A case of a Reye-like syndrome during the course of treatment with VPA was reported. Hyperammonemia and severe liver damage as well as diffuse small droplets in the liver biopsy material were demonstrated. On analysis by gas chromatography/mass spectrometry of the urine immediately after the onset, the metabolites of VPA were detected together with lactate and other substances, and electron microscopic observation of liver biopsy material revealed deformation of mitochondria, disappearance of cristae and electron dense deposits in the matrix.

Transcranial Doppler sonographic studies of cerebral blood flow velocity in neonates.

Using the transcranial Doppler technique to investigate the postnatal and developmental changes of cerebral blood flow in newborn infants, we found that the systolic and mean blood flow velocities increased after birth. A rapid increase in blood flow velocities was demonstrated during the first several days. Pulsatility index, which was initially high, gradually fell after birth and remained stable thereafter. The blood flow velocities of small-for-date infants were determined by their gestational ages. The systolic and mean blood flow velocities were influenced more by postnatal age than by gestational age, birth weight, or body weight. The increase in conceptional age was associated with a decrease in the pulsatility index and an increase in the systolic and mean flow velocities. The transcranial Doppler technique is a useful method and will provide more accurate information about the cerebral hemodynamics in neonates than the previously employed continuous wave Doppler technique.

Ipsilateral and contralateral recordings of auditory brainstem responses to monaural stimulation.

The developmental changes of the ipsilateral and contralateral auditory brainstem responses (ABRs) were studied in 105 normal infants and children. In both ipsilateral and contralateral recordings, the peak and interpeak latencies shortened with increasing age, while the amplitudes of wave V had a tendency to become higher. Contralateral ABR amplitudes were always smaller than those of ipsilateral ABRs. In the contralateral recording, wave I was absent and the contralateral wave II and wave III complex began to separate after birth (25%); separation percentage reached 80-100% at 7 months of age. Our results suggest that the contralateral recording of ABRs is a useful measure of developmental changes in infant auditory pathways.