In vivo serum titanium ion levels following modular neck total hip arthroplasty – 10 year results in 67 patients

The objective of the present cross-sectional study was to determine in vivo titanium ion levels following cementless total hip arthroplasty (THA) using a modular stem system with different shapes for femoral canal fit and multiple neck options. A consecutive series of 173 patients (190 hips) who underwent cementless modular neck THA and a ceramic on polyethylene bearing with a median follow-up of 9 (7–13) years was evaluated retrospectively. According to a standardized protocol, titanium ion measurements were performed on 67 patients using high-resolution inductively coupled plasma-mass spectrometry. Ion levels were compared to a control group comprising patients with non-modular titanium implants (n = 11) and to individuals without implants (n = 23). Modular neck THA did not result in elevated titanium ion levels compared to non-modular THA. Compared to individuals without implants, both modular THA and non-modular THA showed elevated titanium ion levels. Absolute titanium ion levels, however, were comparatively low for both implants. The data suggest that the present modular stem system does not result in elevated systemic titanium ion levels in the medium term when compared to non-modular stems. Further longitudinal studies are needed to evaluate the use of systemic titanium ion levels as an objective diagnostic tool to identify THA failure and to monitor patients following revision surgery.     

Physical Activity,Decision-Making Abilities,and Eating Disturbances in Pre- and Postbariatric Surgery Patients

Background

Physical activity (PA) is considered to have a beneficial influence on executive functioning, including decision-making. Enhanced decision-making after bariatric surgery may strengthen patients’ ability to delay gratification, helping to establish appropriate eating behavior. The objectives of this study were to (1) compare a preoperative group with a postoperative group with regard to daily PA, decision-making, and eating disturbances; and (2) investigate the relationship between these variables.

Methods

The study included 71 bariatric surgery candidates (55 % women, BMI [kg/m²] M?=?46.9, SD?=?6.0) and 73 postoperative patients (57 % women, BMI M?=?32.0, SD?=?4.1; 89 % Roux-en-Y gastric bypass, 11 % sleeve gastrectomy; months postoperative M?=?8.2, SD?=?3.5; total weight loss [%] M?=?33.2, SD?=?8.9) who completed SenseWear Pro₂ activity monitoring. Decision-making was assessed using a computerized version of the Iowa Gambling Task and eating disorder psychopathology using the Eating Disorder Examination-Questionnaire.

Results

The number of patients who were classified as physically inactive was similarly high in the pre- and postoperative groups. No group differences emerged with regard to decision-making, but the postoperative group exhibited less eating disturbances than the preoperative group. No significant associations were found between PA, decision-making, and eating behavior.

Conclusions

Patients after bariatric surgery were not more physically active than bariatric surgery candidates, which should be considered in care programs. Additionally, future research is needed to explore the possible link between PA, patients’ decision-making abilities, and eating disturbances concerning dose-response questions.

     

The role of platelet CD154 in the modulation in adaptive immunity

Platelets’ primary role is hemostasis. However, a growing body of research has demonstrated that platelets are integral to the initiation of an inflammatory response and are potent effector cells of the innate immune response. Activated platelets express CD154, a molecule critical to adaptive immune responses, which has been implicated in platelet-mediated modulation of innate immune responses and inflammation. Recent studies utilizing CD154 knockout mice extend the role of platelet-derived CD154 to the modulation of adaptive immune response by enhancing antigen presentation, improving CD8⁺ T cell responses, and playing a critical function in T-dependent humoral immunity under physiological conditions. Together these data provide a basis for the expansion of the current paradigm of B cell activation and germinal center formation to include a role for platelets.     

Restoration of acoustic orienting into a cortically deaf hemifield by reversible deactivation of the contralesional superior colliculus: the acoustic "Sprague Effect"

Removal of all contiguous visual cortical areas of one hemisphere results in a contralateral hemianopia. Subsequent deactivation of the contralesional superior colliculus (SC) nullifies the effects of the visual cortex ablation and restores visual orienting responses into the cortically blind hemifield. This deficit nullification has become known as the "Sprague Effect." Similarly, in the auditory system, unilateral ablation of auditory cortex results in severe sound localization deficits, as assessed by acoustic orienting, to stimuli in the contralateral hemifield. The purpose of this study was to examine whether auditory orienting responses can be restored into the impaired hemifield during deactivation of the contralesional SC. Three mature cats were trained to orient toward and approach an acoustic stimulus (broadband, white noise burst) that was presented centrally, or at one of 12 peripheral loci, spaced at 15 degrees intervals. After training, a cryoloop was chronically implanted over the dorsal surface of the right SC. During cooling of the cooling loop to temperatures sufficient to deactivate the superficial and intermediate layers (SZ, SGS, SO, SGI), auditory orienting responses were eliminated into the left (contracooled) hemifield while leaving acoustic orienting into the right (ipsicooled) hemifield unimpaired. This deficit was temperature-dependently graded from periphery to center. After the effectiveness of the SC cooling loop was verified, auditory cortex of the middle and posterior ectosylvian and anterior and posterior sylvian gyri was removed from the left hemisphere. As expected, the auditory cortex ablation resulted in a profound deficit in orienting to acoustic stimuli presented at any position in the right (contralesional) hemifield, while leaving acoustic orienting into the left (ipsilesional) hemifield unimpaired. The ablations of auditory cortex did not have any impact on a visual detection and orienting task. The additional deactivation of the contralesional SC to temperatures sufficient to cool the superficial and intermediate layers nullified the deficit caused by the auditory cortex ablation and acoustic orienting responses were restored into the right hemifield. This restoration was temperature-dependently graded from center to periphery. The deactivations were localized and confirmed with reduced uptake of radiolabeled 2-deoxyglucose. Therefore deactivation of the right superior colliculus after the ablation of the left auditory cortex yields a fundamentally different result from that identified during deactivation of the right superior colliculus before the removal of left auditory cortex in the same animal. Thus the "Sprague Effect" is not unique to a particular sensory system and deactivation of the contralesional SC can restore either visual or acoustic orienting responses into an impaired hemifield after cortical damage.     

Multidisciplinary Treatment in Patients With Persistent Pain Following Total Hip and Knee Arthroplasty

In a retrospective study, we evaluated the clinical outcome of multidisciplinary pain therapy (MPT) in a consecutive series of 40 patients with persistent unexplained pain following THA or TKA. Pain intensity, physical capability and psychological status were assessed before MPT (t1), after 3 weeks (t2) and at a mean follow-up of 32 months (t3). At t2, all scores demonstrated a significant improvement compared to the baseline value. At t3, pain intensity, physical capability, and depression levels deteriorated slightly but were still significantly better compared to baseline values. Anxiety scores deteriorated between t2 and t3 and showed no difference in the baseline value. The present study suggests that MPT has beneficial short-term and mid-term effects in this subgroup of patients and may avoid exploratory revision surgery.     

Vaccination levels associated with lack of measles transmission among preschool-aged populations in the United States, 1989-1991

Knowledge of the minimum level of vaccination capable of preventing measles transmission in an age group is helpful for establishing program targets for measles elimination. In 1990, during the measles resurgence in the United States, one-half of cases occurred in children aged <5 years. Although estimated population immunity among persons >or=6 years of age was 93%, immunity was lower and varied widely among preschool-aged children. To examine the association of vaccine coverage at 2 years of age and measles incidence among preschool-aged children, we analyzed ecological studies of measles incidence in Milwaukee (Wisconsin) census tracts, Dallas (Texas) ZIP code areas, and selected cities during the 1989-1991 measles resurgence. In each study area, measles incidence decreased rapidly with increasing measles vaccine coverage and became low or negligible when coverage was >or=80%. Regression analysis also suggested that measles would not be transmitted when vaccine coverage was at least 79%. A minimum vaccine coverage of approximately 80% at the second birthday in census tracts, ZIP code areas, and cities in the United States may be sufficient to prevent measles transmission among preschool-aged children if population immunity is >or=93% among persons >or=6 years of age.     

Patent foramen ovale closure in patients with transient ischemia attack/stroke

Paradoxical embolism through a patent foramen ovale (PFO) has been recognized as a potential cause of transient ischemia attack (TIA) and stroke especially in younger patients. The therapeutic options are medical treatment (antiaggregation or anticoagulation) with an annual recurrence rate of 3% to 4% for stroke or TIA, surgical PFO closure, or catheter closure. Randomized studies are ongoing; however, the results will not be available soon. Since August 1994, we have attempted catheter closure of a PFO in 281 patients (age 17 to 79 years, mean 46.8 +/- 13.2) with paradoxical embolism. Of these, 184 patients had at least one embolic stroke, 112 patients at least one TIA, and 15 patients at least one peripheral embolism. The diameter of the PFO, measured with a balloon catheter, ranged from 3 mm to 24 mm with a mean of 10 +/- 3.5 mm. Implantation of the occluder was technically successful in all patients (two attempts in four patients). Seven different devices were used: 26 Sideris buttoned, 11 ASDOS, 19 Angel Wings, 98 PFO-Star, 37 Cardioseal-Starflex, 57 Amplatzer and, 33 Helex devices. One patient suffered from septicemia and subsequently died. In 2 patients, device embolization occurred during or after the procedure (1 Sideris, 1 PFO-Star; catheter retrieval successful). Thirty-seven patients had other minor complications without long-term sequelae: atrial fibrillation within the first weeks after implantation in five patients, asymptomatic thrombus on the device at routine transesophageal echocardiogram (TEE) in 7 patients (1 Angel Wings, 1 ASDOS, 1 CardioSeal, 4 PFO-Star), and device frame fracture in 25 patients (2 Sideris, 4 ASDOS, 1 Angel Wings, 1 CardioSeal, 17 PFO-Star). No complications occurred with the newer devices (Amplatzer and Helex). A residual shunt after 6 months was found in 5.5% of the patients who had completed their 6-month TEE follow-up. In two patients, a second occluder was implanted because of a residual shunt. During a follow-up period of 1 month to 71 months (mean 12 +/- 16 months, 268 patient years), a recurrence of an embolic event (seven TIA, two stroke) occurred in eight patients. None of these occurred with the newer devices (Amplatzer, Helex). Freedom from recurrence of the combined end point of TIA, ischemic stroke, and peripheral embolism was 95.7% (95% CI: 89.0%-98.4%) at 1 year and 94.1% (95% CI: 80.1-98.4%) at 3 years. Catheter PFO closure is a technically simple procedure. With the newer devices and increasing experience, the success rate has improved and the complication rate has decreased. The advantage of the procedure is that closing the defect means a causal treatment. However, catheter closure of PFO despite a very low morbidity has inherent potential risks like any other interventional procedure. Furthermore, selection of patients who definitely have PFO as the cause of their cerebral event has not been defined. For these reasons, further studies are warranted.