Electrocardiogram studies in llamas

Electrocardiograms (ECG) of 3 captive llamas (Lama glama) were recorded by a telemeter at a farm in Japan. The pattern of the ECGs was similar to the ruminant pattern in the AB lead position. QRS and T-waves were discordant in polarity except in one llama, where the polarity of the T wave changed according to the HR. In the quiet state, the HR varied between 60-80/min depending on the nervousness of the llama. After running and after being held, the HR increased to more than 100/min. During the recordings there were some variations of the HR which could be due to respiratory arrhythmia. Second-degree AV block and supraventricular premature complexes were also found in two llamas.

Crystal structure analysis of omega-amino acid:pyruvate aminotransferase with a newly developed Weissenberg camera and an imaging plate using synchrotron radiation

The three-dimensional structure of omega-amino acid:pyruvate aminotransferase from Pseudomonas sp. F-126, an isologous alpha 4 tetramer containing pyridoxal 5'-phosphate (PLP) as a cofactor, has been determined at 2.0 A resolution. The diffraction data were collected with a newly developed Weissenberg camera with a Fuji Imaging Plate, using synchrotron radiation. The mean figure-of-merit was 0.57. The subunit is rich in secondary structure and comprises two domains. PLP is located in the large domain. The high homology in the secondary structure between this enzyme and aspartate aminotransferase strongly indicates that these two types of enzymes have evolved from a common ancestor.

X-ray diffraction photographs of chicken gizzard G-actin.DNase I complex crystals taken with synchrotron radiation

X-ray diffraction photographs of a chicken gizzard G-actin.DNase I complex crystal have been recorded using the synchrotron radiation beam emitted by the Synchrotron Radiation Source at Daresbury and the Photon Factory at Tsukuba. The resolution limit was extended to 2.4 A and the exposure time was reduced approximately by a factor of 10, when data recorded at the Photon Factory, were compared with those recorded with a conventional rotating-anode source. Using a newly designed Weissenberg camera equipped with a multi-layer line screen, the diffraction data in a 36 degrees oscillation range were recorded on a single film up to 3.5 A resolution.

Crystallographic studies of the chicken gizzard G-actin X DNase I complex at 5A resolution

The structure of the chicken gizzard G-actin X DNase I complex has been determined at 5 A resolution by an X-ray diffraction method. Protein phases were computed by the multiple isomorphous replacement method using four heavy atom derivatives. The mean figure of merit was 0.65. Dimensions of the three molecular species, the complex, G-actin and DNase I, were determined based on the "cypress wood" models derived from the electron density map. The natures of the heavy atom binding sites are discussed in relation to the distinction between the two component molecules. The pattern of successive contacts between actin molecules observed in the present crystal seems unrelated to that found in F-actin.

Power spectral analysis of auditory brain stem responses to pure tone stimuli

Power spectral analysis and digital filtration of the auditory brain stem responses to tone burst stimuli were carried out in three adult subjects with normal hearing. Three dominant peaks (peaks A. B, C), ranging in frequency 50-150, 500-600, and 1000-1100 Hz, were observed in the spectrograms of the responses to 4 kHz at 80 dB SL. Power of higher frequency components (peaks B and C) decreased markedly or disappeared completely with decreased intensity as well as decreased frequency of stimulus, while peak A around 100 Hz consistently appeared regardless of stimulus intensity or frequency. Main spectral components of the individual waves in the ABR were determined as follows: peak A for the slow positive deflection in the response, peak B for waves VI and VII, peak C for waves II and IV, and peaks B and C for waves I, III and V.

Power spectral analysis of auditory evoked response

Five normal hearing adults were examined for power spectral analysis of AER to 1000-Hz pure tone. Major frequency components of responses to stimuli at 50 dB hearing level exist at 1 to 14 c/s. The power spectra of responses to stimuli at 10 dB hearing level are greater than those of the SBA in the frequency components between 3 and 9 c/s; furthermore, the total power of 3 to 9 c/s indicates a clear difference between the 2. Incidentally, at 512-msec analysis time, the total power of 3 to 9 c/s of the AER are significantly greater than that at 1024-msec analysis time, whereas those of the SBA show little discrepancy at the 2; thus at 512-msec analysis time, the total power of 4 to 9 c/s yields a clear difference between the AER and the SBA responses averaged over 50 stimuli even at 10 dB hearing level.

Crystallization and preliminary crystallographic data of chicken gizzard G-actin . DNase I complex and Physarum G-actin . DNase I complex

Smooth muscle G-actin from chicken gizzard and Physarum plasmodium G-actin both interact with DNase I and form 1 : 1 complexes. These complexes were crystallized by using polyethylene glycol 6000 as a precipitant. Both crystals belong to the same orthorhombic space group P2(1)2(1)2(1). The cell dimensions of chicken gizzard G-actin.DNase I complex are a=42.00 +/- 0.07 A, b=225.3 +/- 0.4 A, and c=77.4 +/- 0.1 A, while those of Physarum G-actin.DNase I complex are a=42 A, b=221 A, and c=77 A.

Modification and application of the computerized automatic audiometer

Recently, medical information processing systems applying computers have achieved marked advances in parallel with the development of highly accurate automatic measuring instruments. The authors already in 1974 developed and reported a computerized automatic audiometer containing a micro-computer which stored a program for audiometric procedures. Subsequently the authors have developed a compact, multi-purpose audiometric instrument which executes the standard air-bone conduction audiometry, with the exclusion of masking, automatically with a built-in micro-computer. An outline of the instrument is as follows: 1. The instrument is composed of a memory, a control unit, programs for data processing and measurement, a character display for instructing subjects and an audiogram display. It can be operated manually in the same way as a conventional audiometer. 2. Test errors and any abnormally large differences between the responses of the two ears can be detected automatically, and the tests can then be re-executed manually after finishing the automatic procedure for correction of the data. 3. The instrument is provided with output terminals for connection to an external computer or other peripheral equipment. It is designed to be compact and light weight.

Development of an audiometry data processing system

The development was reported of an electronic data processing system of computerized automatic audiometry and of Bekesy audiometry. This system using a microcomputer has the following features: (1) The large amount of data obtained through (a) automatic audiometry, (b) Bekesy audiometry (measurement at fixed or continuous frequency plus test practice, and (c) the Temporal Tone-Decay test can be stored on-line in real time, and are processed and displayed off-line at any time. (2) When retrieved, the output format of these audiometric data is of the same pattern as the conventional audiogram. (3) The output pattern on the CRT graphic display can be hard-copied whenever desired. (4) The system can be operated manually in the same way as the conventional method. (5) The SISI and DL tests can be executed manually and the resultant data keyed into computer storage. And (6) The operation from the data input to the retrieval output is performed interpretively through the CRT display, so that anyone even without special computer or audiological training can operate it at any time.