Tibial slope in the posterolateral quadrant with and without ACL injury.

INTRODUCTION: An increased tibial slope is a risk factor for rupture of the anterior cruciate ligament. In addition, a tibial bone bruise or posterior lateral impression associated with slope changes also poses chronic ligamentous instability of the knee joint associated with an anterior cruciate ligament (ACL) injury. In the majority of cases, the slope is measured in one plane X-ray in the lateral view. However, this does not sufficient represent the complex anatomy of the tibial plateau and especially for the posterolateral quadrant. Normal values from a "healthy" population are necessary to understand if stability of the knee joint is negatively affected by an increasing slope in the posterolateral area. Until now there are no data about the physiological slope in the posterolateral quadrant of the tibial plateau. MATERIALS AND METHODS: In 116 MRI scans of patients without ligamentous lesions and 116 MRI scans with an ACL rupture, tibial slope was retrospectively determined using the method described by Hudek et al. Measurements were made in the postero-latero-lateral (PLL) and postero-latero-central (PLC) segments using the 10-segment classification. In both segments, the osseous as well as the cartilaginous slope was measured. Measurements were performed by two independent surgeons. RESULTS: In the group without ligamentous injury the mean bony PLL slope was 5.8° ± 4.8° and the cartilaginous PLL slope was 6.7° ± 4.8°. In the PLC segment the mean bony slope was 6.6° ± 5.0° and the cartilaginous slope was 9.4° ± 5.7°. In the cohort with ACL rupture, the bony and cartilaginous slope in both PLL and PCL were significantly higher (P < 0.001) than in the group without ACL injury (bony PLL 9.8° ± 4.8°, cartilage PLL 10.4° ± 4.7°, bony PLC 10.3° ± 4.8°, cartilage PLL 12.8° ± 4.3°). Measurements were performed independently by two experienced surgeons. There were good inter- (CI 87-98.7%) and good intraobserver (CI 85.8-99.6%) reliability. CONCLUSION: The bony and the cartilaginous slope in the posterolateral quadrant of the tibial plateau are different but not independent. Patients with an anterior cruciate ligament injury have a significantly steeper slope in the posterolateral quadrant compared to a healthy group. Our data indicate that this anatomic feature might be a risk factor for a primary ACL injury which has not been described yet. LEVEL OF EVIDENCE: III.

Correlation of T2* relaxation times of the retropatellar cartilage with tibial tuberosity-trochlea groove distance in professional soccer players.

The tibial tuberosity-trochlear groove (TT-TG) distance is a radiographic measurement that is used to quantify malalignment of the patellofemoral joint (PFJ) in cross-sectional imaging. There is an ongoing debate about the impact of the TT-TG-distance on lateral patellar instability and the initiating of cartilage degeneration. In this prospective study, the association of T2* relaxation times and TT-TG distances in professional soccer players was analyzed. 36 knees of 18 professional soccer players (age: 21 ± 2.8 years) were evaluated. Participants underwent knee MRI at 3 T. For qualitative image analysis, fat-saturated 2D PD-weighted Fast Spin Echo (FSE) and T1-weighted FSE sequences were used. For quantitative analysis, T2* measurements in 3D data acquisitions were performed. In a qualitative analysis there was no structural cartilage damage and no abnormalities of the patellar and trochlea shape. The highest T2* values (26.7 ± 5.9 ms) were observed in the central compartment of the patella. The mean TT-TG distance was 10 ± 4 mm (range 3-20 mm). There was no significant correlation between TT-TG distance and T2* relaxation times in all three compartments of the retropatellar cartilage. Our study shows that so long as patellar and trochlear morphology is normal, TT-TG distance alone does not affect the tissue structure of the retropatellar cartilage in professional soccer players.

Lentiviral gene transfer of CTLA4 generates B cells with reduced costimulatory properties.

Peripheral T-cell (TC) tolerance can be induced by tolerogenic antigen-presenting cell (APC). A prerequisite is the reduction or blockade of B7 of APC. Besides dendritic cell, B cells can be used as APC. Here, we show the generation B cells with reduced B7 expression by lentiviral transduction of endoplasmic reticulum (ER)-directed CTLA4. Vectors coding for the human CTL4-Ig were used for the human B-cell line Raji. Transduction efficiency was over 90% (MOI = 3). For the murine B-cell line A20 and for primary mouse B cells, murine CTLA4 was used. We show that B cells with reduced B7 expression reduce the antigen (Ag) specific TC proliferation in vitro. B cells expressing an ER-directed CTLA4 may reduce Ag-specific immune responses.

Resolution of interdental inflammation with 2 different modes of plaque control.

BACKGROUND, AIMS: The aim of the study was to assess the effect on existing plaque and gingivitis of an oral hygiene regimen which utilizes triclosan/copolymer and to compare it with a regimen which uses interdental cleaning devices to control the interdental inflammation. METHOD: For this investigation, 39 subjects were recruited. They were examined for plaque and gingivitis using the criteria of Turesky modification of the Quigley-Hein index and the papillary bleeding index. Plaque and gingivitis were only scored interdentally. Following the baseline examination, the subjects were randomly assigned into 2 groups. The control group used a dentifrice identical to the test dentifrice but without triclosan/copolymer; subjects in this group were taught to brush their teeth with the modified Bass technique and were instructed to additionally use appropriate interdental cleaning devices. The test group used a dentifrice containing triclosan/copolymer (Colgate Total). They were not instructed to use interdental cleaning devices. RESULTS: Both groups were re-examined after 4 weeks, and 4 and 7 months. In both groups, plaque and gingivitis levels were modestly reduced, more pronounced in the anterior and less in the posterior teeth. CONCLUSIONS: This investigation demonstrated that a dentifrice containing triclosan in combination with a copolymer can reduce plaque and gingival inflammation to levels comparable to regular interdental cleaning.

Psychological reactions during polar expeditions and isolation in hyperbaric chambers.

BACKGROUND: Psychological data from environments that are considered as analog to space was collected from 68 subjects; 18 in hyperbaric chambers, 16 in polar expeditions, and 34 on Arctic stations. The objective was to identify psychological reactions expected in different phases of spaceflights and examine personality variables associated with superior adaptation. METHOD: Helmreich Personality Characteristic Inventory was administered before the isolation. Adaptation to the environment was assessed through a questionnaire once a week. RESULTS: Crews in hyperbaric chambers indicated a steady increase in coping over the isolation. Polar expeditions members reported high aggressiveness and anxiety in the first quarter and an increase in homesickness over time. A personality characterized by strong expressiveness and instrumentality ("the right stuff") predicted superior adaptation in hyperbaric chambers. CONCLUSION: The data suggest that isolation in hyperbaric chambers and polar expeditions should be considered as models for different aspects of the space environment.

European isolation and confinement study. Mental performance.

Six EMSInauts were confined for 28 days in a hyperbaric chamber complex at a low overpressure. During this period they were repeatedly given four different standard mental performance tests: (1) Operational Test of sustained attention vigilance; (2) short-term memory; (3) visual reaction time; and (4) cognitive evoked brain potentials (N100 and P300). The aim of the study was to determine whether there were any general or specific effects on mental performance during the isolation period. For the simple mental performance tests (operational test and visual reaction time), a distinct learning effect over the 28 days of isolation could be detected. On the more cognitive demanding tasks such as in the short-term memory test, patterns of impairment were found. Of the cognitive evoked brain potentials recorded, the noncognitive N100 wave latency was unchanged throughout the isolation period. The P300 wave latency, related to cognitive functioning, showed lower values in the middle and higher values at the end of the isolation period, compared with the pre-isolation values. Although a few individual, transient impairments of function were noticed in the more demanding tests, it is concluded that the mental performance of the six EMSInauts appeared to remain basically unchanged throughout the isolation phase, both at the group level and the individual level.

European isolation and confinement study. Group functioning and communication.

Six EMSInauts were isolated in the hyperbaric chambers at NUTEC for a period of 28 days at 5-msw overpressure. Based on previous studies of analogous conditions, the hypothesis was advanced that group and communication problems could possibly occur during the isolation period, and that this could be partly related to personality aspects. The scientific methods for the present study consisted of the following: (1) the team members were systematically observed through wide-angle cameras, and the activities in the working chamber were taped during the entire isolation period; (2) daily questionnaires regarding group functioning and communication were administered; and (3) post-isolation assessment interviews were given. Results were obtained by analysis of: (1) video tapes from the daily meetings; (2) questionnaires on group behavior and communication; (3) post-isolation interviews; and (4) personality inventories (DMT, Helmreich Test, MMPI). The following observations were made: 1. All team members were able to complete the 4-week isolation period while remaining functioning. 2. The commander became ever more central during the isolation period. Communications went more directly through him and less between the EMSInauts. At the same time he became evaluated less positively by the other EMSInauts. 3. There was a steady increase in emotional responses among all EMSInauts during the isolation period. In particular, there was an increase in negative emotional content. 4. Week 3 was evaluated by the EMSInauts as being the most positive period. They scored themselves then as being very task oriented. 5. The EMSInauts gave a low score to problems with the mission control room personnel, indicating few problems. There were indications of temporary increases during week 2 and at the end of the isolation period. In summary, it can be stated that all team members completed the 4-week isolation in good condition. The commander developed increasing control during the isolation period, which resulted in increasingly negative responses towards him from the other team members. During the isolation period there was an increase in emotional content. In particular, during the last week there was an increase of frustrations. There were few communication problems with mission control, though the scores were elevated in week 2 and on the final two days.

European isolation and confinement study. Workload and stress: effects on psychosomatic and psychobiological reaction patterns.

Six healthy males, the EMSInauts, were isolated in hyperbaric chambers for a period of 28 days at 5-msw overpressure. During that period they had to carry out meaningful operational and research tasks in addition to monitoring their psychological and physiological reactions. The actual workload was evaluated and compared with the planned workload, and its effects on symptomatology and psychobiology. The perceived workload and its effects on psychosomatic symptomatology and on some biological indices were monitored. Thus it was possible to evaluate how the workload carried during 4 weeks of isolation affected the psychological and biological well-being of the six EMSInauts. The following three types of assessments were performed: 1. Workload assessment: The objective workload was calculated based on the schedule which was revised daily, and the actual load calculated by the commander. A workload questionnaire was administered daily after each working session. 2. Psychosomatic assessment: Morning and evening questionnaires were administered daily. The state of health and of anxiety were also evaluated. 3. Biological indices: Cortisol, testosterone, adrenalin, and noradrenaline were determined once a week. In addition, cardiac activity was monitored every day. The workload assessment showed that on the average the planned workload was accomplished in slightly less than the scheduled time. The workload was not perceived as severe in terms of cognitive, emotional, and physical load. The group rated the support received from each other and from the mission control personnel as average, with minor changes during the isolation period. They gave a high rating to the amount of control they had over their activities. Fatigue and tension were scored in the middle range. The psychosomatic assessment showed that there were few symptoms, and these were mostly of low severity. The most common symptom was general fatigue. Furthermore, minor dizziness, headache and light tremor was in some cases reported. The sleep quality was good, but complaints about poor sleep increased somewhat with the passing of time. Few and mostly minor health problems were experienced during isolation. Only one EMSInaut had to miss one day of work due to a bout of flu. The state of anxiety was below that of the general population throughout the isolation period. The biological indices used showed no evidence of stress from the workload handled during the isolation period. The level of the "stress hormone" cortisol actually decreased during isolation. The adrenalin excretion, which tends to go up during acute stress, remained unchanged during this period. Neither was there any evidence of changes in cardiac activity throughout the isolation period.(ABSTRACT TRUNCATED AT 400 WORDS)

HPNS effects among 18 divers during compression to 360 msw on heliox.

Heliox compression deeper than 16 ATA can lead to EEG changes associated with confusion and somnolence. In man the symptoms termed the high pressure neurologic syndrome (HPNS) can also include increased tremor, memory problems, dizziness, nausea, and vomiting. In a series of 3 dives at NUTEC, a compression profile developed for operational use down to 360 msw was evaluated. In each dive 6 different divers were compressed to 360 msw on heliox. Neuropsychologic and neurophysiologic testing were performed repeatedly. The HPNS testing revealed only mild effects of the compression. Only 3 divers had impairments of more than 2 SD in peripheral motor function compared to their predive average. Memory was impaired periodically in 2 divers. The same was found for perceptual speed and reasoning. Fifty percent of the divers had an increase of more than 2 SD in postural tremor, but that had minimal effect on their motor performance. Six of the 18 divers had an EEG power spectrum with both alpha band inhibition and theta increase. While the performance impairment was most marked around 240 msw, the EEG changes occurred mainly deeper than 300 msw. In only 1 of the 18 divers marked EEG changes, marked tremor increase, and marked cognitive performance impairment were observed at the same time. Although mild HPNS was observed, the divers were little impaired during the compression to 360 msw. The results confirm that using a compression profile with rates decreasing progressively with increasing depth, and with several intermediate stops, provides fit divers at depth. By using standard batteries of HPNS testing we were able to obtain evidence for the acceptability of this compression profile.

Incorporation of the antimicrobial protein seminalplasmin into lipid bilayer membranes.

The interaction between seminalplasmin, an antimicrobial protein from bull semen, and lipid bilayers has been investigated. The fluorescence of the single tryptophan residue of the protein was measured. In the presence of phosphatidylcholine or phosphatidic acid bilayer vesicles the fluorescence maximum was shifted to shorter wavelengths, indicating transfer of the tryptophan to a more apolar environment. Circular dichroism spectra show an increased alpha-helical content for the protein in the presence of lipid. Quenching experiments clearly show the incorporation of the protein with the tryptophan localized near the bilayer surface. The shift of the tryptophan fluorescence emission was used to monitor the lipid phase transition in phosphatidylcholine membranes.