Radiographic monitoring of the distal insertion of the calcaneofibular ligament in anatomical reconstructions of ankle instabilities: A preliminary cadaveric study.

BACKGROUND: The purpose of the study therefore was to determine radiographic landmarks that support the identification of the insertion site of the distal calcaneofibular ligament (CFL) in anatomic ankle ligament reconstructions. METHODS: In 10 lower limb cadaver specimens the midpoint of the distal CFL insertion was dissected and marked with a nail inserted orthogonally. On a standardized lateral radiograph in neutral ankle position a horizontal tangent was aligned to the deepest visible concavity of the tarsal sinus and one vertical tangent to the farthest posterior convexity of the talus. Additionally, a line was drawn from the radiographically marked distal CFL to the fibular insertion of the CFL to determine the CFL-fibular angle. RESULTS: In relation to the radiographic tangents intersection the mean deviation of the depicted CFL nails was 2.2mm [SD ± 1.1 mm] leading to an angular, circular to slightly oval 6 mm insertion. The scatter-plot of the marked positions convened along a line from the supposed fibular CFL insertion to the intersection in all cases. The mean CFL-fibular angle was 131.7° [SD ± 3.16°]. CONCLUSIONS: Determining a virtual intersection between a horizontal tangent aligned to the deepest visible concavity of the tarsal sinus and one vertical tangent aligned to the farthest posterior convexity of the talus on a standardized lateral radiograph in neutral ankle position supports an anatomic insertion of the distal calcaneofibular ligament most probably.

Moment-knee angle relation in well trained athletes.

The purpose of this work was to investigate whether different modes of long-term competitive physical activity cause functional differences in the moment-knee angle relation of the M. quadriceps femoris (QF). Therefore, a sample (n = 40) of young male competitive endurance runners, cyclists, triathletes and tennis players performed isometric maximal voluntary knee extensions (MVC) with their stronger leg at six different knee joint angles while keeping the hip joint angle constant. Muscle activation of QF-muscles during MVC was estimated using surface electromyography (EMG). Moments and EMG data of each subject were normalized to the largest value produced at any knee joint position [% Max.]. No significant differences in the normalized [% Max.] moment-knee angle relation of the QF were found between endurance runners, cyclists and triathletes. Despite few unsystematic exceptions, no functional differences in the normalized moment-knee angle relation of the QF occurred among tennis players and the endurance-oriented athletic groups. Obtained by curve fitting, the optimal knee joint angle for moment production was not significantly different among all athletic groups. We conclude that long-term competitive endurance running, cycling, triathlon and tennis do not provoke functional differences in the moment-knee angle relation of the whole QF.

Changes in gait patterns in 10-year-old boys with increasing loads when walking on a treadmill.

This study examined the gait pattern, heart rate and blood pressure in children carrying school bags of 0 (as control), 10, 15 and 20% of their own body weight whilst walking on a treadmill. When compared to the 0% load condition, the 20% load condition induced a significant increase in trunk forward lean, double support and stance duration, and decreased trunk angular motion and swing duration and a prolonged blood pressure recovery time. The 15% load condition induced a significant increase in trunk forward lean and prolonged blood pressure recovery time. No significant difference was found in the measured parameters between the 10 and 0% load conditions. We concluded that back pack weight should not exceed 10% of body weight in 10-year-old boys.

Mass spectroscopy and chromatography of the trichloromethyl radical adduct of phenyl tert-butyl nitrone.

Positive structural identification of the PBN-trichloromethyl spin adduct in vitro was accomplished with the use of high pressure liquid chromatography and/or gas chromatography coupled with mass spectrometry. Both thin layer and liquid chromatography were used to separate a complex mixture of compounds from rat liver extracts treated with CCl4 in vitro and in vivo. Deuterated PBN's (PBN-d9; tert-butyl deuteration, or PBN-d14; both phenyl and tert-butyl deuteration) were also used to aid in the mass spectral analysis of spin adducts from liver extracts of CCl4 exposed rat livers, since the tert-butyl group fragment ion. C4D9+ (m/z = 66) is always present for PBN and PBN spin adducts. In addition, the masses of the ion peaks increase by the amount of deuteration, i.e. an increase of 9 for PBN-d9 or PBN-d14 in comparison to normally synthesized PBN.

Methods of extraction and high-performance liquid chromatographic analysis of butylated hydroxytoluene from the tissues and serum of rats.

Butylated hydroxytoluene (BHT) is a phenolic antioxidant which is widely used in foods and has been shown to inhibit chemical carcinogenesis in the mammary gland induced by 7,12-dimethylbenz(a)anthracene. However, its mechanism of action as a tumor inhibitor is unclear. The purpose of this work was first to develop a method for extracting and quantitating BHT and then to determine the amounts that accumulate in the tissues and serum of rats as a starting point for looking at mechanistic possibilities in the inhibition of mammary carcinogenesis. Methodology of extracting BHT from rat tissues and serum was developed using a modified lipid extraction procedure. The sensitive nature of reverse-phase high-performance liquid chromatography proved useful in detecting and quantifying BHT after its extraction from biological tissues. All tissues were taken from animals consuming semipurified diets with and without 0.3% BHT for various periods of time (weeks). BHT was found in much higher levels in mammary tissue than in the liver and serum of rats. The lipid content in mammary tissue appears to be predictive of the amount of BHT found in this tissue, presumably because of the lipophilic character of the antioxidant.

Effects of nonsteroidal antiestrogens, analog II and tamoxifen, on a metastatic transplantable rat mammary tumor.

This study was designed to determine whether treatment with the nonsteroidal antiestrogens analog II and tamoxifen given three times per week, 2 weeks before and 2 weeks after tumor cell transplantation, influenced the metastasis of a transplantable, metastatic rat mammary tumor, DMBA-4. Following transplantation of 2,000 viable tumor cells into the fifth and sixth mammary fat pads of 50-day-old inbred, female WF rats, all rats in all 3 groups displayed primary tumors by 5 weeks post tumor transplant. Analog II delayed the primary tumor development when compared to the time of the primary tumor development in either the control (untreated) or tamoxifen-treated groups. No metastatic tumors were found in the analog II-treated group 5 weeks after tumor transplantation, and only 1 animal in the tamoxifen-treated group had a secondary tumor, whereas 50% of the control animals had metastatic tumors. Six weeks after tumor implantation, palpable secondary tumors had developed in 40% of the analog II-treated group and 80% of the tamoxifen-treated group, whereas 60% of the control animals had developed secondary tumors. By the end of the study (7 wk) no differences existed between primary or secondary tumor incidences or between control and antiestrogen-treated groups. Both antiestrogens were effective in delaying the development of secondary tumors, especially during the time of treatment. Following cessation of treatment, analog II prevented metastatic tumor development for up to a month and tamoxifen, for 3 weeks. Further studies are indicated to determine if continuous treatment can effectively inhibit metastatic tumor development indefinitely.

The interaction of dietary fat and antiestrogen treatment on DMBA-induced mammary tumors in the rat.

This study was designed to determine whether an estrogenic mechanism is involved in dietary fat-modulated tumor development and growth. Female Sprague-Dawley rats were placed on a semipurified low-fat (2% fat), high-saturated fat (20% fat), or high-polyunsaturated fat (20% fat) diet at 21 days of age. A single dose of 7,12-dimethylbenz[a]anthracene (DMBA, 10 mg) was administered intragastrically at 50 days of age. Two studies were performed. One tested the effectiveness of antiestrogen treatment (either tamoxifen or analog II) on tumor development when it was given one week prior to and one week after DMBA treatment in animals consuming a high-polyunsaturated fat diet. The second six-week study tested the antiestrogen effectiveness in arresting tumor growth and in producing regressions of established DMBA-induced tumors in rats consuming various levels and types of fat. The results of these studies indicate that both antiestrogens employed reduced the rate of growth and increased the number of regressions of established DMBA-induced tumors. In general, this was true in animals fed diets with a high content of either saturated or polyunsaturated fats and to a lesser extent in animals fed a low-fat diet. Tamoxifen produced a somewhat greater reduction in the growth of established tumor than did analog II. However, analog II, which is a more biologically "pure" antiestrogen, reduced the incidence of animals with mammary tumors and total tumor burden when administered one week before and one week after DMBA dosing. Tamoxifen, which is a partial estrogen-agonist, did not alter tumor incidence, but it did reduce the total tumor burden under these same experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)