Characterization of vestibular potentials evoked by linear acceleration pulses in the chinchilla

The objective of this study was to improve vestibular evoked potentials as a qualitative parameter for vestibular function in small laboratory animals. Linear upward acceleration pulses (up to 8 g within 1 ms) were applied to the head of anesthetized chinchillas. Electrophysiologic responses recorded by a chronically implanted electrode within the facial nerve canal consisted of an initial negative potential, labeled N1, within the first millisecond following the onset of acceleration. This potential was followed by a series of positive and negative potentials found to be highly labile to acoustic masking. The initial negative potential was only minimally sensitive to acoustic masking and persisted following surgical cochlear ablation, but completely disappeared following administration of potassium chloride into the inner ear. Recorded from the contralateral ear, N1 was unaffected by these procedures. Amplitudes of N1 decreased with attenuating stimulus intensity (1.45 microV/dB), whereby N1 latencies slightly increased (-0.015 ms/dB). These data, when coupled with the ability to completely abolish N1 with potassium intoxication while the contralateral ear remained intact, indicate that this potential represents electrophysiologic activity resulting from activation of the ipsilateral vestibular labyrinth.     

Variation in cytoskeletal assembly during spreading of progressively subcultivated human embryo fibroblasts (IMR-90)

The cytoskeletons of early and late passage IMR-90 human diploid fibroblasts have been directly imaged in replicas of Triton X-100 extracted cells during spreading following reseeding. All cells from both young and sensescent cultures exhibit a cytoskeletal network of actin microfilaments, intermediate (10 nm) filaments, microtubules, and interconnecting thin filaments (6-8 nm in diameter) which do not interact with heavy meromyosin. Early passage cells assemble linear aggregates of actin filaments within 1 h of spreading. By 4 h of incubation, these bundles establish a structural bond with the cell membrane which results in resistance by the plasmalemma to detergent extraction at these sites. Furthermore, these membrane regions are associated with developing stress fibers of well-spread cells. In contrast, late passage cells exhibit slower spreading which correlates with a retarded assembly of actin bundles. In addition, by 8 h of spreading, cells of older cultures do not exhibit the regions of membrane-actin interaction which impart detergent resistance to the plasmalemma. We conclude that the ability to reassemble actin-actin and actin-membrane association during cell spreading is reduced with increased serial subcultivation of cells.     

Depth distribution of ion-implanted argon in gadolinium and samarium films

The development of a model and theoretically evaluated distributions for impurities injected by ion bombardment into growing films are given. The influence of ion range distribution function, diffusion, impurity-defect interaction and film and substrate material differences upon the impurity concentration profiles is investigated. The possibility of uniform impurity distribution in the main part of the film with a sharp concentration gradient into the substrate is shown. The influence of diffusion leads to a decrease of gaseous impurity concentration in the film and penetration of impurities into the substrate; the relation of impurity diffusion coefficients and the segregation coefficient value is essential when the film and the substrate are made of different materials. Taking into account the trapping of impurities by defects we found that the distribution of the ‘free’ (mobile) impurities is inhomogeneous with a maximum near the growth boundary, this inhomogeneity is decreased with increased diffusion, while defect concentration increases. The concentration profiles of the trapped impurities (impurity-defect complexes) are very different, the complexes become distributed more homogeneously and the concentration of complexes increases as diffusion and the defect concentration increase.By use of secondary ion mass-spectrometry (SIMS) a distribution of ion-implanted argon through the film and part of the substrate depth was investigated as well as the distribution of the film and substrate materials themselves, using gadolinium and samarium films obtained by vacuum condensation on (100) molybdenum monocrystal under simultaneous 100 and 600 eV argon irradiation. The argon distribution through the film is found to be almost uniform with an exponential decrease in the substrate for gadolinium films at an energy of 100 eV. A considerable argon accumulation at the film-substrate boundary is found at an energy of 600 eV. For samarium films at an energy of 100 eV an anomalous argon and samarium penetration into the substrate as well as argon penetration into the layer deposited without irradiation of the film is obtained.     

Diarrhea associated with Vibrio fluvialis in the United States

We report the isolation in the United States of Vibrio fluvialis from the stools of a patient who had severe watery diarrhea without fever and who subsequently died. V. fluvialis, a known enteric pathogen in other parts of the world, should be suspected in patients with watery diarrhea, especially in coastal areas.     

Introduction of integrated care pathways for patients with multiple sclerosis in an inpatient neurorehabilitation setting

Rehabilitation of progressive neurological disorders such as multiple sclerosis poses particular problems, and clear setting of goals and clinical audit are essential for effective management. Integrated care pathways (ICPs) offer a unique opportunity to document and audit the rehabilitation process. This preliminary study has shown that ICPs are useful in both assessing process and auditing goals. Their introduction has led to the identification of the key worker role within the neurorehabilitation unit (NRU), and has provided an opportunity to increase the participation of patients and carers in the rehabilitation process. Continuing refinement of the pathway is necessary, and its application to other neurological disorders such as cerebrovascular accident may be appropriate.     

Sex of the Speaker, Sex of the Listener, and Listening Comprehension

One hundred thirty-seven male and two hundred twenty-five female undergraduates at the University of Wisconsin—Milwaukee heard recordings of 14 short, informative messages. Each message had been recorded by one of seven male or seven female upper level communication students. Following each message subjects responded to six multiple choice items about the content of the message. Analysis of variance showed no significant difference in listening scores for male and female subjects. A significant interaction between sex of listener and sex of speaker was found, but this interaction accounted for so little of the total variance that it was deemed of little practical importance. It was concluded that neither the sex of the listener nor the interaction of sex of listeners and sex of speakers were of much consequence in determining the listening scores of the subjects of this experiment.