Control of upright standing posture during low-frequency linear oscillation.

We examined the effects of anteroposterior movement of a sled on human upright standing. Each of six healthy men stood on the platform of a sled in the dark. The sinusoidal acceleration was provided, from 0.02 to 0.04 G, followed by 0.06 and 0.08 G, at a stroke length from 6 to 10 m and then to 14 m. Low acceleration (0.02 and 0.04 G) induced body sway, pivoting on the ankle joint. High acceleration (0.06 and 0.08 G) increased body sway, but the head-neck joint remained locked upright. The electromyographic recordings of the lower leg muscles revealed continuous tonic EMG activities of the gastrocnemius and tibialis anterior muscles at acceleration of 0.02 and 0.04 G, while reciprocal activation was observed at 0.06 and 0.08 G. During head movement, the neck muscles were slightly activated tonically at acceleration of 0.02 and 0.04 G, but they were markedly and tonically activated at 0.06 and 0.08 G. We speculate that the sled oscillation caused body sway in proportion to the acceleration, with the ankle joint playing a principal role. Analysis of neck movement also revealed that the head was held in a fixed upright position, indicating that the vestibulocollic reflex might tonically activate the neck muscles.

[New method for closure of median sternotomy: usefulness of barbed staple].

In this report, 15 cases using straight staple (group A) and 35 cases using barbed staple (group B) were compared for the purpose of investigating efficacy for median sternal closure. The staples were placed by a Stapilizer powered metaphyseal staple system following partial transsternal fixation with two wires. As a means of assessing the status of back out, which is a major cause of poor fixation, the back out rate (BOR) was measured on lateral sternal radiographies. The average BOR was found to be 33.8% in group A and 21.2% in group B (p < 0.001). Barbed staples seemed to be more useful for sternal fixation than straight staples. This method of applying barbed staples had the advantages of speed, ease of insertion and noninvasion of the retrosternal region. It should be recommended in cases with severe adhesion of the retrosternal region after coronary operation.

Effects of linear movements on upright standing position.

This study investigated the effects of antero-posterior movement on the upright standing posture in the humans. Subjects were asked to stand on a platform in a linear accelerator (sled) in the dark. At a fixed distance of sled movements in an antero-posterior direction, peak speed was changed by sinusoidal modes run at 0.02 G, 0.04 G, 0.06 G and 0.08 G. At lower speeds (0.02 G and 0.04 G) joints moved in parallel, but at higher speeds (0.06 G and 0.08 G) the hip flexed or extended in the direction of the sway. At lower speeds (0.02 G and 0.04 G) EMG in lower leg exhibited co-activated patterns in both forward and backward accelerations at lower speeds (0.02 G and 0.04 G), but at higher speeds (0.06 G and 0.08 G) TA was activated with reciprocal inhibition of GC to maintain the body in equilibrium in a reflexive manner. This reciprocal inhibition may be due to main reflex control elicited by motor functions as a result of the linear acceleration. The threshold of speed was assumed to be from 0.04 G to 0.06 G for all but one subject.

Acne fulminans coexisting with pyoderma gangrenosum-like eruptions and posterior scleritis.

A 30-year-old Japanese man presented with an erythematous, papulonodular eruption on his face and upper trunk, which rapidly progressed into severely exuberant, ulcerative lesions with a confluent tendency. His other symptoms included a high fever and general malaise. Complete blood cell counts showed neutrophilia with increased percentages of myelocytes and metayelocytes. The systemic administration of corticosteroids improved his skin lesions, leaving scars and milia. During tapering of corticosteroids, however, the patient developed posterior scleritis of his eyes and pyoderma gangrenosum-like eruptions on the lower legs. Our patient's history suggests that pyoderma gangrenosum-like eruptions and posterior scleritis are disorders associated with acne fulminans.

Telescience testbed for biomedical experiments in space morphological and physiological experiments of rat musculoskeletal system.

As the second telescience testbed experiment we were examined sophisticated processes of biomedical experiment, such as an implantation of a transmitter into the hamster's abdominal cavity, non-stressful blood sampling, large amount of blood collection, muscle extirpation and biopsy from the hamsters on February 6-8, 1990. To make clear the differences between successful results obtained by an experienced hand and by a non-experienced one, three operators were selected for three successive experimental days; an engineer who had never experienced any biological experiment, a non-biology student, who experienced on biological experiments, and a veterinary surgeon. Surgical procedures need much experiences on maneuvering and understanding of theory to shorten the elapse time. Especially for a non-experienced hand, graphic instructions were much helpful to understand and to maneuver the procedures. Continuous recordings of ECG from a operator and PIs were of an advantage to grasp an extent of the mental strain, which was compared with their reports requested after end of each experimental day. The mental strain was not related to degrees of scientific achievement, but showed faithfully difficulty of each experimental procedure. Training effects on PIs in successive experimental days were found in their instructions for the operator to let understand the procedures.

Telescience testbed in human space physiology.

The present telescience testbed study was conducted to evaluate the feasibility of physiological experimentation under restricted conditions such as during simulated weightlessness induced by using a water immersion facility, a reduced capacity of laboratory facilities, a delay and desynchronization of communication between investigator and operator, restrictions of different kinds of experiments practiced by only one operator following a limited time line and so on. The three day's experiments were carried out following the same protocols. The operators were changed every day, but was the same the first and the third day. The operators were both medical doctors but not all round experts in the physiological experimentation. The experimental objectives were: 1) ECG changes by changing water immersion levels, 2) blood pressure changes, 3) ultrasonic Echo-cardiographic changes, 4) laser Doppler skin blood flowmetry in a finger, 5) blood sampling to examine blood electrolytic and humoral changes. The effectiveness of the testbed experiment was assessed by evaluating the quality of the obtained data and estimating the friendliness of the operation of the telescience to investigators and operators.

Simultaneous presence of EBNA-positive and colony-forming cells in peripheral blood of patients with infectious mononucleosis.

EBNA-positive lymphoblast cells were detected in 0.1 to 0.9% of the T-cell-depleted lymphocytes obtained from peripheral blood samples of five patients with infectious mononucleosis (IM). The same blood specimens from four of the five patients contained cells that formed EBNA-positive colonies in soft agar containing EBV antibodies. The ratio of the colony formers to EBNA-positive cells was higher in blood samples taken early in the disease than in those obtained in later stages of the disease. The present results strongly suggest that EBV-transformed cells are present in the peripheral circulation of IM patients and that such cells can directly give rise to immortalized cell lines in vitro.