Search

The recovery pattern of threshold shift (TS) and 'dynamic' changes in the stereocilia after exposure to high-level impulse noise in guinea pigs were investigated. 33 albino guinea pigs were exposed to 10 impulse noises at the rate of 1/min. The noise had peak level of 166 dB SPL and a duration of 0.1 ms. Thirteen of the exposed animals were used to systematically measure threshold shifts at regular intervals from 0.5 h to 30 days post-exposure by click auditory cortex evoked response (AC-ER). Twelve of the animals who had typical TS at the same intervals were killed for scanning electron microscopic examination. The recovery pattern of threshold shifts was non-monotonic, which was different from that seen with continuous noise. There was an increase in TS after the exposure and the maximum level of TS was found at 8 h post-exposure. Morphological analysis also showed delayed changes in the stereocilia after exposure. The severity of changes in the stereocilia reached a peak at 8 h, at which time complete fusion of hair bundles took place. The tectorial material found on the tips of the stereocilia may be responsible for the sequence of the changes.

We describe the construction and use of two classes of cDNA cloning vectors. The first class comprises the lambda EXLX(+) and lambda EXLX(-) vectors that can be used for the expression in Escherichia coli of proteins encoded by cDNA inserts. This is achieved by the fusion of cDNA open reading frames to the T7 gene 10 promoter and protein-coding sequences. The second class, the lambda SHLX vectors, allows the generation of large amounts of single-stranded DNA or synthetic cRNA that can be used in subtractive hybridization procedures. Both classes of vectors are designed to allow directional cDNA cloning with non-enzymatic protection of internal restriction sites. In addition, they are designed to facilitate conversion from phage lambda to plasmid clones using a genetic method based on the bacteriophage P1 site-specific recombination system; we refer to this as automatic Cre-loxP plasmid subcloning. The phage lambda arms, lambda LOX, used in the construction of these vectors have unique restriction sites positioned between the two loxP sites. Insertion of a specialized plasmid between these sites will convert it into a phage lambda cDNA cloning vector with automatic plasmid subcloning capability.

Percutaneous liver biopsies were performed in 40 adult patients with acute or chronic liver disease. Real-time sector scan ultrasound of the right upper quadrant was obtained just before biopsy, 1 day after biopsy, and in 10 randomly selected cases 7 days after biopsy. Twenty patients were randomized, by sealed envelope, to 6-h and 20 patients to 24-h postbiopsy bed rest. Nine patients (23%) had ultrasound-detected hematomas 1 day after liver biopsy (7 intrahepatic, 2 subcapsular). Five of these patients had been randomized to 6-h and 4 to 24-h bed rest. Follow-up ultrasound at 7 days in the 10 randomly selected patients failed to reveal any hematomas not seen on day 1 (n = 6) and showed complete or partial resolution of those that had been detected previously (n = 4). Significant drops in systolic and diastolic blood pressure and increases in pulse rate were common postbiopsy findings, and were unrelated to hematoma formation. The results of this study indicate that intrahepatic and subcapsular hematomas are common after percutaneous liver biopsy. The length of postbiopsy bed rest (6 vs. 24 h) does not appear to influence the frequency of this complication.