Functional analysis of the effect of the posterior stabilising cam in two total knee replacements. A comparison of the Insall/Burstein and Bisurface prostheses

The Bisurface knee prosthesis (BP) has a posterior stabilising cam (ball-and-socket joint) in the mid-posterior region of the femorotibial joint in an attempt to improve the range of movement. Based on an in vitro weight-bearing study contact areas of the Insall/Burstein 2 (IB2) and the BP knee were compared using pressure-sensitive films. The stability afforded by the cam was evaluated by means of dislocation distances in the vertical and horizontal planes. Significant adverse anterior translation in mid-flexion was not observed with the BP knee since the cam was effective above 60 degrees of flexion. At flexion of 60 degrees or more, the total contact areas were larger, as the cam represented a weight-bearing surface. The dislocation distances for the BP knee compared favourably with those for the IB2 knee. We conclude that the cam of the BP knee allows good movement, stability and wear.

Determination of 4-nonylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate and other alkylphenols in fish and shellfish by high-performance liquid chromatography with fluorescence detection

A simple and highly sensitive method is described for the HPLC determination of 4-nonylphenol (NP), 4-nonylphenol mono- (NP1EO) and diethoxylates (NP2EO) in fish and shellfish together with bisphenol A (BPA), 4-tert.-butylphenol (BP) and 4-tert.-octylphenol (OP). The NP, NP1EO, NP2EO and other alkylphenols in the samples are extracted with acetonitrile and the lipid in the sample extract is eliminated by partitioning between hexane and acetonitrile. After Florisil PR clean-up the sample extract is analyzed by HPLC with a fluorescence detection. Recoveries in Japanese smelt, carp and corbicura are 81.8-84.3% for NP, 83.5-84.3% for NP1EO, 90.5-96.2% for NP2EO, 70.7-72.9% for BPA, 71.0-73.4% for BP and 77.1-83.2% for OP spiked at 0.5 microg each chemical per 5 g of the fish and shellfish samples. The detection limits are 2 ng/g for NP, NP1EO and NP2EO, and 1ng/g for BPA, BP and OP.

Coactivation of the flexor muscles as a synergist with the extensors during ballistic finger extension movement in trained kendo and karate athletes

To analyse the effects of ballistic property training on ballistic finger extension movement, surface electromyographic pattern (EMGs) of the finger extensor and flexor muscles and the acceleration signal of the middle finger were recorded in trained kendo and karate athletes, and sedentary non-athletic men. Ballistic finger extension did not show the characteristic triphasic EMG pattern reported in single joint, but a coactivation of flexor and extensor muscles. Reaction time (RT) in kendo (143 +/- 12 msec) and karate (146 +/- 11 msec) athletes were significantly shorter than that in the control (176 +/- 12 msec). The shortenings of the RT were attributed to both the shortenings of premotor time and motor time. The delay of the flexor muscles discharge after those of the extensors in kendo (0.8 +/- 7.0 msec) and karate (-0.2 +/- 5.0 msec) athletes was significantly shorter than in control (12.7 +/-5.6 msec). These results suggest that the RT is shortened through motor learning in the kendo and karate athletes who trained for momentary movements; and that the flexor muscles may play an important role as a synergist in heightening the efficiency of ballistic finger extension in coordination with the extensor muscles.

[Evaluation of photographic subtraction images obtained from sialograms]

Photographic subtraction used in the examination of salivary glands was compared with conventional sialography. Subtraction images obtained from the duct system of parotid glands demonstrated the same images as were obtained by conventional sialography. In duct system of the submaxillary glands, however, the conventional sialograms were clearer than those images obtained by subtraction procedures. Subtraction images could provide the outward form of salivary glands, especially in the parotid glands. In most cases, sialography with subtraction provides valuable informations in diagnosing salivary gland diseases. But, the results showed that the necessity of applying this modality must be examined carefully.

[Experimental study on tooth fractures in young rats]

The influence of tooth fractures on growth of rat incisors was examined with soft X-ray radiography, xeroradiography and microradiography. Thirty young rats were used in this study and experimental fractures were produced on the mandibular left incisors. Radiological observations were carried out immediately, 7, 14, 21, 28 and 35 days after fracturing. The soft X-ray radiograms obtained immediately after fracturing showed clear radiolucent images. The radiopacity of the fractured regions gradually increased from the 7th day. Enamel hypoplasia was observed from the 7th day, and it moved towards the edge of the incisors with the growth of the fractured teeth. The xeroradiograms obtained at each term demonstrated as same findings as those obtained with soft X-ray radiography. The microradiograms obtained immediately after fracturing showed no noteworthy findings except for the clear radiolucent area of the fractured regions. Fine radiopaque lines along the edges of fractured regions were observed from the 7th day. Dentin-like radiopaque calcified masses were observed from the 14th day.

Serological survey of hepatitis B virus (HBV) markers in out- and in-patients in a university hospital

Of a total of 13,596 patients and 1,876 blood donors in a university hospital examined, 550 (4.1%) patients and 31 (1.7%) donors possessed hepatitis B surface antigen (HBsAg) in their blood. The higher incidence of HBsAg in the patient population than in the blood donors verified the view that medical personnel and hospitalized patients are at increased risk of acquiring HBV infection. To assess the actual hazard of the HBsAg-positive patients, we examined hepatitis Be antigen (HBeAg) and its antibody (anti-HBe) status of 228 HBsAg-positive patients and found that 39 (18%) were positive for HBeAg and 168 (74.5%) were positive for anti-HBe. This indicated that only one fifth of the HBsAg-positive patients should be drawn attention in terms of HBV transmission within a hospital.