Control of fracture reduction robot using force/torque measurement.

We have developed a surgical robotic system for femoral fracture reduction employing indirect traction. Indirect traction in fracture reduction is a generally used surgical method for preventing complications such as bone splits caused by high stress on bones. For traction, a patient's foot is gripped by a jig and pulled to the distal side. Indirect traction has the advantage of distributing bone stress by utilizing a strong traction force; however, this procedure does not accurately control the proper positioning of fractured fragments when a surgical robot is used. The human leg has knee and an ankle joints, and thus robotic motion presents problems in not being able to directly propagate reduction motion to a fractured femoral fragment, rendering control of bone position difficult. We propose a control method for fracture reduction robots using external force/torque measurements of the human leg to achieve precise fracture reduction. Results showed that the proposed method reduced repositioning error from 6.8 mm and 15.9 degrees to 0.7 mm and 5.3 degrees, respectively.

Characterization of soluble artificial proteins with random sequences.

The structural and catalytic properties of two soluble random proteins, RP3-42 and RP3-45, of 141 amino acid residues were investigated. Although no marked secondary structure was detected by CD spectrum, sedimentation equilibrium and small-angle X-ray scattering studies showed that they form an oligomeric structure and are as compact as the molten globule. The random proteins have low but distinct esterase activity; the values of the second-order rate constant for the hydrolysis of p-nitrophenol were 0.78 and 1.39 M(-1) s(-1) for RP3-42 and RP3-45, respectively. The differences in the properties of the random and the native proteins are discussed from the evolutionary point of view.

[A study on button-type alkali-manganese battery in Ringer's solution--limited injury factor on the electric discharge in body].

Many cases of tissue injury caused by a button battery appearing as a foreign body have been reported in the otolaryngology field. However, there have been very few studies on the mechanism of tissue injury by batteries. In this study, we inserted a button-type battery into 4cm3 of Ringer's solution, which is similar to serous fluid, at both room temperature (20 degrees C) and body temperature (37 degrees C), and observed the electro-chemical reactions between the negative and positive terminals over 6 hours. We identified the products of these reactions, measured the remaining electromotive force (EMF), and observed the changes in pH and metallic ion concentrations over time. In conclusion, the following three major groups of factors causing tissue injury were suggested: 1) At the positive terminal the HCl acid and HClO produced broke down, and chlorine gas was dissolved into the solution. 2) At the negative terminal, the OH- radical was produced by reduction of water. 3) Potassium hydroxide (KOH), nickel (Ni2+), manganese (Mnn+), chrome (Crn+), and lead (Pb2+) leaked from the battery at the poles, due to oxidation, and were partially dissolved in the serous fluid. These factors may result in serious tissue injury. In addition, each electro-chemical reaction occurred in a very short time at these relatively high temperatures, and as a result, may be the cause of these tissue injuries.

[Case report of a foreign body in the nasal cavity: experimental research on limited damage].

We report here a case of serious nasal cavity tissue damage caused by a foreign substance, specifically, a button-shaped battery. The patient was a three-year-old boy who inserted a button-shaped battery into his left nasal cavity. On examination, we found necrosis of the nasal mucosa, cartilage and bone. In addition, the nasal cavity structure was severely damaged. In a follow-up experiment, we inserted a similar button-shaped battery, pre-soaked in a salt solution, into a rabbit's nasal cavity and measured daily changes in PH and discharge over time. In addition, we assessed how much nasal cavity tissue was damaged in a pathological specimen. We found that the chief factor mediating tissue damage, among those we tried, was strong base production with low voltage discharge. Under these conditions the nasal cavity is damaged in a short time.

The endoscopic intratumor administration of OK-432 in gastric cancer unsuitable for surgery.

In eleven patients with gastric cancer who could not be operated on because of advanced age, refusal of surgery, or the presence of complications, the streptococcal preparation OK-432 was administered, both intradermally and by direct injection into the tumor under endoscopic guidance. Via gastric x-ray and endoscopic examinations, the tumor was observed to disappear in two cases-one advanced cancer and one early gastric cancer endoscopically. Particularly in the latter case repeated biopsies revealed no evidence of cancer cells. All patients developed fever after intratumor injection, but in no case was it necessary to discontinue administration, and no other serious side effects were noted. The endoscopic injection of OK-432 appears to be a safe and useful form of therapy for gastric cancer unsuitable for surgery.