Influence of Cook Method and Degree of Doneness on Beef Flavor Attributes in Round Steaks

ObjectivesIt has been well established that cooking method, marbling level, and cooked internal temperature endpoint affect beef flavor, the most important driver of consumer acceptance. However, beef cuts respond differently to cooking method and cooked internal temperature endpoint based on their inherent chemical characteristics.Materials and MethodsTreatments were: beef cuts (inside round, bottom round, and eye of round); USDA beef quality grade (upper two-thirds Choice and Select); cooking methods (pan grill, stir fry, stew no marinade, stew marinade, and roast); and internal cook temperature endpoints (58, 70, and 80°C). The pan grill cook method included 0.25 and 0.75 in samples from each muscle type. The stir fry cook method treatment was limited to 0.25 in cuts, which were cut into 1.00 in strips prior to cooking. The marinated and non-marinated stew cook method treatments included 0.25 and 0.75 in samples from each muscle. These samples were then cut into 0.25 × 1.00 × 1.00 in and 0.75 × 1.00 × 1.00 in samples prior to cooking. Stew marinated samples were marinated with 118 mL water, 90 mL lemon juice, 30 mL canola oil, 5 mL salt, and 2.5 mL pepper. Two lb roasts were cut from bottom round and eye of round subprimals and inside round subprimals were cut into 2.00 in roasts prior to cooking. An expert descriptive beef flavor and texture attribute panel evaluated each sample using 16-point scales for flavor and texture attributes. Warner-Bratzler shear force (WBSF) were determined. The trained panel results and WBSF values were analyzed using Proc Means and Proc GLMMIX procedures of SAS (version 9.4, SAS Institute, Cary, NC) with a predetermined α of 5%.ResultsQuality grade impacted flavor for the inside round (P < 0.05). USDA quality grade had minimal effect on tenderness as expected, as beef round cuts are highly active muscles in the animal and contain considerable amounts of connective tissue. Cooking method and internal cook temperature endpoint, or cooking time for the stewing cooking treatment, impacted beef flavor to a greater extent (P < 0.05). When pan fried, thicker cuts resulted in more positive flavor attributes. For cuts that were roasted, cooking to higher internal temperatures resulted in higher levels of beef identity, roasted, and umami flavors and less serumy/bloody flavors, as well as decreased tenderness (P < 0.0001), especially in inside round roasts. Marinated round cuts were more tender than their non-marinated counterparts (P < 0.0001). Cuts that were thinner and had longer cooking times were more tender but had more off-flavor attributes (P < 0.05).ConclusionCut thickness, cooking method, length of cooking or internal cook temperature endpoint, and presence of marinade affected flavor and texture of bottom round, eye of round, and inside round cuts. This data will be useful in providing consumer and food service personnel recommendation on how to maximize the flavor and texture of beef round cuts.

Short-term antidepressant treatment has long-lasting effects, and reverses stress-induced decreases in bone features in rats

Antidepressants are among the most-prescribed class of drugs in the world and though weight gain is a common outcome of antidepressant treatment, that effect is not well understood. We employed an animal model comprised of 2 weeks of chronic restraint stress with antidepressant treatment, followed by diet-induced obesity. We showed that short-term antidepressant treatment had long-lasting effects, not only leading to weight gain, but also enhancing trabecular and cortical bone features in rats; therefore, weight gain in this model was different from that of the classic diet-induced obesity. Late in the post-restraint recovery period, antidepressant-treated animals were significantly heavier and had better bone features than saline-treated controls, when assessed in the distal femoral metaphysis. The propensity to gain weight might have influenced the rate of catch-up growth and bone allometry, as heavier animals treated with fluoxetine also had enhanced bone features when compared to non-stressed animals. Therefore, short-term antidepressant treatment ameliorated the long-term effects of stress on body growth and bone. Growth and bone structural features were associated with leptin levels, and the interaction between leptin levels and antidepressant was significant for bone mineral content, suggesting that short-term antidepressants in the context of long-term diet-induced obesity modified the role of leptin in bone formation. To our knowledge this is the first study reporting that short-term antidepressant treatment has long-lasting effects in restoring the effects of chronic stress in body weight and bone formation. Our findings may be relevant to the understanding and treatment of osteoporosis, a condition of increasing prevalence due to the aging population.

Hospital effect on infections after four major surgical procedures: outlier and volume-outcome analysis using all-inclusive state data

BACKGROUND

Hospital volume is known to have a direct impact on the outcomes of major surgical procedures. However, it is unclear if the evidence applies specifically to surgical site infections.

AIMS

To determine if there are procedure-specific hospital outliers [with higher surgical site infection rates (SSIRs)] for four major surgical procedures, and to examine if hospital volume is associated with SSIRs in the context of outlier performance in New South Wales (NSW), Australia.

METHODS

Adults who underwent one of four surgical procedures (colorectal, joint replacement, spinal and cardiac procedures) at a NSW healthcare facility between 2002 and 2013 were included. The hospital volume for each of the four surgical procedures was categorized into tertiles (low, medium and high). Multi-variable logistic regression models were built to estimate the expected SSIR for each procedure. The expected SSIRs were used to compute indirect standardized SSIRs which were then plotted in funnel plots to identify hospital outliers.

FINDINGS

One hospital was identified to be an overall outlier (higher SSIRs for three of the four procedures performed in its facilities), whereas two hospitals were outliers for one specific procedure throughout the entire study period. Low-volume facilities performed the best for colorectal surgery and worst for joint replacement and cardiac surgery. One high-volume facility was an outlier for spinal surgery.

CONCLUSIONS

Surgical site infections seem to be mainly a procedure-specific, as opposed to a hospital-specific, phenomenon in NSW. The association between hospital volume and SSIRs differs for different surgical procedures.

Factors predictive of patient outcome following total wrist arthrodesis

Aims

Total wrist arthrodesis (TWA) produces a spectrum of outcomes. We investigated this by reviewing 77 consecutive TWA performed for inflammatory and post-traumatic arthropathies, wrist instability and as a salvage procedure.

Patients and Methods

All operations were performed by a single surgeon using a specifically designed pre-contoured dorsally applied non-locking wrist arthrodesis plate at a single centre.

Results

Median post-operative Buck-Gramcko Lohman (BGL), Disabilities of the Arm, Shoulder and Hand and Patient Rated Wrist Evaluation scores at six years (interquartile range (IQR) 3 to 11) were 9 (IQR = 6 to 10), 19 (IQR = 7 to 45) and 13 (IQR = 1 to 31) respectively. Polyarticular inflammatory arthritis and female gender were associated with poorer patient-reported outcomes, although the effect of gender was partly explained by higher rates of inflammatory disease among women. Return to work was negatively influenced by workers’ compensation and non-inflammatory wrist pathology. There was no difference in complication rates for inflammatory and non-inflammatory indications. Take home message: Polyarticular inflammatory arthritis is a risk factor for adverse patient-reported outcomes in TWA. Furthermore, when compared with patients without inflammatory arthritis, dorsally applied pre-contoured plates can be used for wrist arthrodesis in patients with inflammatory arthritis without an increased risk of complications. Cite this article: Bone Joint J 2016;98-B:647–53.

Development and validation of a VISA tendinopathy questionnaire for greater trochanteric pain syndrome, the VISA-G

BACKGROUND

Greater trochanteric pain syndrome (GTPS) is common, resulting in significant pain and disability. There is no condition specific outcome score to evaluate the degree of severity of disability associated with GTPS in patients with this condition.

OBJECTIVE

To develop a reliable and valid outcome measurement capable of evaluating the severity of disability associated with GTPS.

METHODS

A phenomenological framework using in-depth semi structured interviews of patients and medical experts, and focus groups of physiotherapists was used in the item generation. Item and format clarification was undertaken via piloting. Multivariate analysis provided the basis for item reduction. The resultant VISA-G was tested for reliability with the inter class co-efficient (ICC), internal consistency (Cronbach's Alpha), and construct validity (correlation co-efficient) on 52 naïve participants with GTPS and 31 asymptomatic participants.

RESULTS

The resultant outcome measurement tool is consistent in style with existing tendinopathy outcome measurement tools, namely the suite of VISA scores. The VISA-G was found to be have a test-retest reliability of ICC2,1 (95% CI) of 0.827 (0.638-0.923). Internal consistency was high with a Cronbach's Alpha of 0.809. Construct validity was demonstrated: the VISA-G measures different constructs than tools previously used in assessing GTPS, the Harris Hip Score and the Oswestry Disability Index (Spearman Rho:0.020 and 0.0205 respectively). The VISA-G did not demonstrate any floor or ceiling effect in symptomatic participants.

CONCLUSION

The VISA-G is a reliable and valid score for measuring the severity of disability associated GTPS.

The health status of people claiming compensation for musculoskeletal injuries following road traffic crashes is not altered by an early intervention programme: a comparative study

OBJECTIVE

To compare health outcomes among claimants compared to those who were ineligible or choose not to lodge a compensation claim. We also evaluated the effect of an early intervention programme on the health outcomes of the participants.

DESIGN

Prospective comparative study using sequential cohorts.

SUBJECTS

People presenting to hospital emergency departments with mild to moderate musculoskeletal injuries following road traffic crashes.

INTERVENTION

referral to an early intervention programme for assessment by musculoskeletal physician, pain management education, promotion of self-management and encouragement of early activity.

MAIN OUTCOMES

The 36-Item Short-Form Survey (SF-36); Hospital Anxiety and Depression Scale (HADS) and Functional Rating Index (FRI) scores were assessed at post-crash and at 12 months.

RESULTS

At 12 months, mean scores in six and five of the SF-36 domains were significantly lower among participants who claimed compensation versus those who chose not to claim or were ineligible, respectively. Differences in mean SF-36 scores ranged from 3.0 ('general health perception') to 8.0 units ('role limitations due to physical problems'). Participants who claimed compensation had 6.3- and 4.6-units lower SF-36 physical component score compared to those who were ineligible (p=0.001) or chose not to claim (p=0.01), respectively. Participants who claimed compensation reported a worse HADS-depression score of 6.46 versus 4.97 and 4.69 observed in those who were ineligible (p=0.04) or did not claim (p=0.01). Claimants had worse FRI scores compared to non-claimants (p=0.01) and those who were ineligible (p=0.01). The early intervention did not improve health outcomes, 12 months after injury.

CONCLUSIONS

Claiming compensation was associated with a worse health status for people with soft tissue injuries caused by road traffic crashes. The health status in people claiming compensation was not altered by an early intervention programme.

Biological responses of beef steers to steroidal implants and zilpaterol hydrochloride

British × Continental steers (n = 168; 7 pens/treatment; initial BW = 362 kg) were used to evaluate the effect of dose/payout pattern of trenbolone acetate (TBA) and estradiol-17β (E2) and feeding of zilpaterol hydrochloride (ZH) on serum urea-N (SUN), NEFA, IGF-I, and E2 concentrations and LM mRNA expression of the estrogen (ER), androgen (ANR), IGF-I (IGF-IR), β1-adrenergic (β1-AR), and β2-adrenergic (β2-AR) receptors and IGF-I. A randomized complete block design was used with a 3 × 2 factorial arrangement of treatments. Main effects were implant (no implant [NI], Revalor-S [REV-S; 120 mg TBA + 24 mg E2], and Revalor-XS [REV-X; 200 mg TBA + 40 mg E2]) and ZH (0 or 8.3 mg/kg of DM for 20 d with a 3-d withdrawal). Steers were fed for 153 or 174 d. Blood was collected (2 steers/pen) at d -1, 2, 6, 13, 27, 55, 83, 111, and 131 relative to implanting; LM biopsies (1 steer/pen) were collected at d -1, 27, 55, and 111. Blood and LM samples were collected at d -1, 11, and 19 relative to ZH feeding. A greater dose of TBA + E2 in combination with ZH increased ADG and HCW in an additive manner, suggesting a different mechanism of action for ZH and steroidal implants. Implanting decreased (P < 0.05) SUN from d 2 through 131. Feeding ZH decreased (P < 0.05) SUN. Serum NEFA concentrations were not affected by implants (P = 0.44). There was a day × ZH interaction (P = 0.06) for NEFA; ZH steers had increased (P < 0.01) NEFA concentrations at d 11 of ZH feeding. Serum E2 was greater (P < 0.05) for implanted steers by d 27. Serum trenbolone-17β was greater (P < 0.05) for implanted steers by d 2 followed by a typical biphasic release rate, with a secondary peak at d 111 for REV-X (P < 0.05) implanted steers. Implanting did not affect mRNA expression of the ANR or ER, but the IGF-IR and the β1-AR and β2-AR were less (P < 0.05) for REV-S than NI at d 55 and β2-AR mRNA was less (P < 0.05) for REV-S than for REV-X. Expression of the IGF-IR and the β1-AR at d 111 was greater (P< 0.05) for REV-X than for REV-S and NI at d 111, and the β2-AR was less (P< 0.05) for REV-S than for REV-X. Feeding ZH did not affect mRNA expression of the β1-AR and β2-AR. Both implanting and feeding ZH decreased SUN, but a greater dose of TBA + E2 did not result in further decreases. In addition, feeding ZH increased serum NEFA concentrations. Metabolic changes resulting from implanting and feeding ZH may aid in explaining steer performance and carcass responses to these growth promotants.

An estimation of the incidence of squeaking and revision surgery for squeaking in ceramic-on-ceramic total hip replacement: a meta-analysis and report from the Australian Orthopaedic Association National Joint Registry

Squeaking arising from a ceramic-on-ceramic (CoC) total hip replacement (THR) may cause patient concern and in some cases causes patients to seek revision surgery. We performed a meta-analysis to determine the incidence of squeaking and the incidence of revision surgery for squeaking. A total of 43 studies including 16,828 CoC THR that reported squeaking, or revision for squeaking, were entered into the analysis. The incidence of squeaking was 4.2% and the incidence of revision for squeaking was 0.2%. The incidence of squeaking in patients receiving the Accolade femoral stem was 8.3%, and the incidence of revision for squeaking in these patients was 1.3%.

An early intervention programme had no detectable influence on the health status of people with musculoskeletal injuries following road traffic crashes: comparative study

OBJECTIVE

To compare the health status of people with minor injuries from road traffic crashes that are exposed to an early, active intervention programme (intervention group) with those receiving usual care (control group) over a 12 month period.

DESIGN

Prospective comparative study using sequential cohorts.

SUBJECTS

People presenting to hospital emergency departments with mild to moderate musculoskeletal injuries following road traffic crashes.

MAIN OUTCOME MEASURES

Physical Component Score (PCS) and Mental Component Score (MCS) of the Short Form 36 (SF-36) health status measure; Hospital Anxiety and Depression Scale (HADS) and the Functional Rating Index (FRI) recorded immediately post-crash, at 6 months and at 12 months after injury.

RESULTS

There were 95 participants allocated to the control group and 98 allocated to the intervention group. Participants were enrolled at a mean of 9.3 days following the crash. There were no significant differences in baseline health measures between the groups. Apart from a small improvement in anxiety for the intervention group, there were no significant differences in health status between the groups. Twenty percent of participants in the intervention group received treatment from external healthcare providers that was inconsistent with the recommendations of the intervention programme.

CONCLUSIONS

The intervention programme failed to result in a clinically significant improvement in health outcomes compared with usual care. There is some evidence to suggest that the intervention had some psychological benefits, as evidenced by the small improvement in anxiety levels. Limited adherence, frequent use of co-interventions, or other factors (such as intervention content or intensity) may have reduced its effect.

Uptake of 17β-trenbolone and subsequent metabolite trendione by the pinto bean plant (Phaseolus vulgaris)

Manure from livestock feeding operations is commonly applied to agricultural fields as an alternative to commercial fertilizers. Trenbolone acetate (TbA) is a synthetic growth promoter frequently utilized in beef cattle feeding operations. Metabolites of TbA can be present in manure and subsequently applied to fields. Fate ofTbA metabolites 17β-trenbolone (17βTb), 17α-trenbolone (17αTb), and trendione (TbO) have been assessed in manure and soils, but plant uptake in agricultural fields is not fully understood. The objective of this study was to investigate potential plant uptake and biotransformation of 17βTb using the pinto bean plant (Phaseolus vulgaris). Vegetated (n=20) and control sands (n=16) were amended with 17βTb at a level of 1μg/g once per week for a total of four weeks. Sand, above-ground plant portion and below-ground plant portion were collected each week and then analyzed for 17βTb, 17αTb, and TbO. By week four, low concentrations of 17βTb (10±4.9μg/g fresh weight) were taken up into the roots of plants and, to a much lesser extent, translocated throughout the plant (0.04±0.02μg/g fresh weight). Extensive transformation of 17βTb to the metabolite trendione (TbO) occurred in vegetated sand, while minimal TbO was detected in control sand. These results suggest the biotransformation of 17βTb to TbO is predominantly through microbial degradation. Trenbolone (Tb) metabolites can then be taken up into plants but remain concentrated in the roots with only slight translocation to above ground portions of the plant. After four weeks, maximum observed concentrations of total Tb (parent+metabolites) in fresh plant tissues were 33.0μg/g in roots and 0.25μg/g in leaves. No phytotoxicity was observed to pinto bean plants throughout the four week study.

The influence of fault on health in the immediate post-crash period following road traffic crashes

OBJECTIVE

To compare the early health status of people who sustained injuries during road traffic crashes (RTC) in which they were at fault (AF), with people who sustained injuries in RTC in which they were not at fault (NAF).

DESIGN

Prospective cohort study.

SUBJECTS

People presenting to the emergency department with mild to moderate musculoskeletal injuries following RTC.

MAIN OUTCOME MEASURES

Physical Component Score (PCS) and Mental Component Score (MCS) of the Short Form 36 (SF-36) health status measure; Hospital Anxiety and Depression Scale (HADS) and the Functional Rating Index (FRI) recorded immediately post-crash.

RESULTS

193 people participated in the study and were enrolled a mean of 9.3 days following the crash. The mean age was 37 years and 60% were female. 71% were NAF. There was a significantly higher number of females in the NAF group (65% compared with 35% males; p<0.001). Neck and back injuries were reported by 90.4% of the NAF group compared to 69.1% of the AF group (p<0.001). There were no significant differences in PCS, FRI or pain intensity between the two groups at a mean of 9.3 days after the crash. The mean MCS for the NAF group was significantly worse than for the AF group (31.4 compared to 37.3; p = 0.005). The SF-36 domain revealed a significantly worse adjusted mean role emotional score for the NAF group (23.4 compared to 32.5, p = 0.002). Females had significantly worse MCS score than males (30.6 and 38.1 respectively; p<0.001) and worse adjusted mean anxiety and depression scores (10 compared to 7.8; p = 0.002 and 7.6 compared to 5.5; p = 0.002 respectively).

CONCLUSIONS

Despite there being no difference in physical health status, the NAF group demonstrated more emotional and mental disturbance than the AF group; and this was significantly worse for females. Treatment strategies should focus on addressing early pain and disability as well as providing appropriate psychological interventions, particularly for people not at fault following RTC.

Accumulation and effects of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) exposure in the green anole (Anolis carolinensis)

Environmental contamination by energetic compounds is an increasing international concern, although little is known of their accumulation in and affect on wildlife. Reptiles are often good models for contaminants studies due to natural history traits that increase their potential for exposure. We report a study to assess accumulation and effects of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX, High Melting Explosive) in green anoles (Anolis carolinensis). Acute oral toxicity (LD(50)) was estimated to exceed 2000 mg/kg body weight in adult male and female anoles using a standard up-and-down method. Accumulation of HMX was assessed in adult females via dietary exposure and into eggs by two routes (directly from the soil and via maternal transfer). HMX readily accumulated into adult females in a dose-dependent manner and into eggs following both exposure pathways. However, total HMX in soil-exposed eggs was up to 40-times greater than those exposed via maternal transfer. Although there was a suggestion of an HMX-induced reduction in body weight in adult females, overall there were no effects observed over the 12 week exposure period. The only significant effect on eggs was a 50% reduction in hatching success for eggs exposed to 2000 mg/kg HMX in the soil during incubation. Growth and survival of hatchlings was not affected by HMX exposure. Our results demonstrate that HMX accumulates through the food chain and into eggs from the soil, but likely poses minimal threat to lizards except to hatching success in eggs incubated in soils with HMX levels near maximum environmental concentrations.

Precision analysis of a multi-slice ultrasound sensor for non-invasive 3D kinematic analysis of knee joints

Currently the standard clinical practice for measuring the motion of bones in a knee joint with sufficient precision involves implanting tantalum beads into the bones to act as fiducial markers prior to imaging using X-ray equipment. This procedure is invasive in nature and exposure to ionizing radiation imposes a cancer risk and the patient's movements are confined to a narrow field of view. In this paper, an ultrasound based system for non-invasive kinematic evaluation of knee joints is proposed. The results of an initial analysis show that this system can provide the precision required for non-invasive motion analysis while the patient performs normal physical activities.

The association of compensation on longer term health status for people with musculoskeletal injuries following road traffic crashes: emergency department inception cohort study

OBJECTIVE

To compare the health status of people claiming compensation for injuries sustained in road traffic crashes (RTC), with people who do not claim compensation.

DESIGN

Prospective cohort study.

SETTING

Australian Capital Territory, Australia and a fault based common law compensation scheme.

SUBJECTS

People presenting to the emergency department with mild to moderate musculoskeletal injury following RTC.

MAIN OUTCOME MEASURES

Physical Component Score (PCS) and Mental Component Score (MCS) of the Short Form 36 (SF-36) health status measure, Hospital Anxiety and Depression Scale (HADS) and the Functional Rating Index (FRI). These measures are recorded immediately post crash, at 6 and 12 months post crash.

RESULTS

95 people participated in the study and were enrolled a mean of 8.6 (median 8) days following the crash. 86% were followed up to 12 months after injury. Mean age was 37 years, 61% were female and 91% were employed at the time of their injury.33%ultimately claimed compensation, and 25% engaged a lawyer. There were no major differences in baseline personal characteristics or injury related factors between the groups. As expected, involvement as a passenger and in multiple vehicle crashes, were more frequent in the group claiming compensation. Over the duration of the study claiming compensation was associated with lower SF-36 PCS (5.5 (95%CI 8.6 to 2.4), p = 0.001), greater HADS-Anxiety (1.7 (95%CI 0.2–3.3), p = 0.048), and worse FRI (11.2 (95%CI 3.9–18.5), p = 0.003). There was a highly significant improvement in health status between baseline and 6 months after injury, but no further significant change between 6 and 12 months after injury. There was no difference in rate of improvement between the groups. Claiming compensation and psychological factors were independent predictors of worse health status at 12 months.

CONCLUSION

In this study the group claiming compensation had overall worse health status following mild to moderate musculoskeletal injuries over the course of the study. There was no difference in rate of improvement between the groups. However, it is not possible to determine whether this negative effect was due to claiming compensation itself or the presence of other unmeasured factors.

Bicruciate-stabilised total knee replacements produce more normal sagittal plane kinematics than posterior-stabilised designs

Bicruciate-stabilised total knee replacement (TKR) aims to restore normal kinematics by replicating the function of both cruciate ligaments. We performed a prospective, randomised controlled trial in which bicruciate- and posterior-stabilised TKRs were implanted in 13 and 15 osteo-arthritic knees, respectively. The mean age of the bicruciate-stabilised group was 63.9 years (sd 10.00) and that of the posterior-stabilised group 63.2 years (sd 6.7). A control group comprised 14 normal subjects with a mean age of 67.9 years (sd 7.9). The patellar tendon angle (PTA) was measured one week pre-operatively and at seven weeks post-operatively during knee extension, flexion and step-up exercises.

At near full extension during step-up, the bicruciate-stabilised TKR produced a higher mean PTA than the posterior-stabilised TKR, indicating that the bicruciate design at least partially restored the kinematic role of the anterior cruciate ligament. The bicruciate-stabilised TKR largely restored the pre-operative kinematics, whereas the posterior-stabilised TKR resulted in a consistently lower PTA at all activities. The PTA in the pre-operative knees was higher than in the control group during the step-up and at near full knee extension. Overall, both groups generated a more normal PTA than that seen in previous studies in high knee flexion. This suggested that both designs of TKR were more effective at replicating the kinematic role of the posterior cruciate ligament than those used in previous studies.

Does ultrasound correlate with surgical or histologic findings in greater trochanteric pain syndrome? A pilot study

BACKGROUND

Greater trochanteric pain syndrome can be severely debilitating. Ideal imaging modalities are not established, treatments are not reliably evaluated, and the underlying pathology is not well understood.

QUESTIONS/PURPOSES

Using surgical and histopathology findings as a gold standard, we therefore determined the positive predictive value of preoperative ultrasound assessment for greater trochanteric pain syndrome recalcitrant to nonoperative management. In addition, we report the outcomes of gluteal tendon reconstructive surgery using validated clinical and functional outcome tools and evaluate the contribution of the tendon and bursa to greater trochanteric pain syndrome.

PATIENTS AND METHODS

We reviewed 24 patients who had combined gluteal tendon reconstruction and bursectomy. Preoperative ultrasound imaging was compared with surgical findings. In the absence of a greater trochanteric pain syndrome specific outcome tool, surgical outcomes for pain and function were assessed via a 100-mm visual analog scale, the modified Harris hip score, and the Oswestry Disability Index. Strength also was measured. The tendon and bursa tissue collected at surgery was histopathologically reviewed.

RESULTS

In our small study, ultrasound had a high positive predictive value for gluteal tendon tears (positive predictive value = 1.0). Patients reported high levels of pain relief and function after surgery; tendon and bursa showed pathologic changes.

CONCLUSIONS

Ultrasound appears to be clinically useful in greater trochanteric pain syndrome; reconstructive surgery seems to relieve pain and the histopathologic findings show tendinopathy and bursa pathology coexist in greater trochanteric pain syndrome.

LEVEL OF EVIDENCE

Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Elevated serum cardiac troponin I in older patients with hip fracture: incidence and prognostic significance

INTRODUCTION

Cardiovascular complications are the main causes of morbidity and mortality in patients with osteoporotic hip fracture (HF). The aim of this prospective study was to evaluate the incidence and prognostic significance of elevated cardiac troponin I (cTnI) in the early peri-operative period in older patients with HF.

MATERIALS AND METHODS

A blind evaluation of myocardial injury as detected by cTnI elevation in 238 consecutive older patients with low-trauma HF (mean age 81.9 +/- 7.8 (SD) years; 72% females). Data on demographic and clinical characteristics, in-hospital mortality, hospital length of stay and discharge destination were collected prospectively. Serum cTnI level was analysed from blood collected routinely in the first 72 h of hospital admission.

RESULTS

Sixty-nine (29%) patients had elevated cTnI (>0.06 microg/l) but myocardial injury was clinically recognised in only 23 (33%) and only 24 (34.8%) had a history of coronary artery disease (CAD). Patients with elevated cTnI were significantly older, more often had American Society of Anaesthesiologist status score >or=3, a history of CAD or stroke and more often were current smokers than the patients without cTnI elevation. In multivariate regression analysis only age was an independent predictor of cTnI elevation. Patients with cTnI release were twice as likely to have a length of stay >or=20 days (P = 0.047) and 2.7 times more likely to be discharged to a long-term residential care facility (RCF) (P = 0.013). cTnI level >or=1 microg/l was a strong independent predictor of all-cause mortality with 98.3% specificity and 89.1% negative predictive value.

CONCLUSION

Peri-operative myocardial injury is common in older HF patients but is frequently unrecognised clinically. Elevated blood cTnI level is an independent predictor of prolonged length of hospital stay (>or=20 days), need for long-term RCF and mortality (if cTnI >or=1 microg/l).

Quality of life after infection in total joint replacement

PURPOSE

To compare the health-related quality of life and functional outcomes of patients with and without periprosthetic infection after total joint replacement (TJR).

METHODS

62 uncomplicated TJRs and 34 TJRs complicated with deep infection were compared using a visual analogue scale for satisfaction, the Western Ontario and McMaster Universities Osteoarthritis Index, Assessment of Quality of Life, and Short Form-36.

RESULTS

Patients with complicated TJR had significantly poorer satisfaction in outcome (p<0.0001) and disease-specific functional outcomes (p<0.0001). Six of the 8 health-related quality-of-life scores were also significantly poorer (p<0.05). These results persisted after controlling for age, sex, and follow-up period in a multiple regression analysis.

CONCLUSION

Infection following TJR reduces patient satisfaction and seriously impairs functional health status and health-related quality of life. When hospitals are balancing the costs of preventative measures with the costs of treating infection in TJR, the effect on patients' quality of life must be considered. Our findings argue strongly for allocation of health care resources to minimise the occurrence of infection after TJR.

Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam

This Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current nu(mu) interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27 x 10(20) 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336+/-14 events. The data are consistent with nu(mu) disappearance via oscillations with |Delta(m)2/32|=2.74 +0.44/-0.26 x10(-3)eV(2) and sin(2)(2theta(23))>0.87 (68% C.L.).

Outcomes for older patients with hip fractures: the impact of orthopedic and geriatric medicine cocare

OBJECTIVES

To assess the impact of a specifically designed model of orthopedic-geriatric cocare on hip fracture (HF) outcomes.

SETTING

Tertiary teaching hospital (level I trauma center).

DESIGN

Prospective observational study with a retrospective (historical) control. Data on 951 consecutive patients 60 years of age or older admitted to the authors' institution with a nonpathologic HF over a 7-year period (1995 to 2002) were analyzed. Between 1995 and 1997, medical problems were managed by a geriatric medicine (GM) consultation-only service (retrospective audit). In 1998, a GM registrar began overseeing daily medical care with weekly geriatrician consultant review (prospective study). Outcomes for 2 time periods were compared: a 3-year period before (no GM; 504 patients) and a 4-year period after (GM; 447 patients) the introduction of GM cocare.

MAIN OUTCOME MEASUREMENTS

Postoperative medical complications, mortality, length of stay, discharge destination, use of thromboprophylaxis, and antiosteoporotic treatment.

RESULTS

While comparing 2 periods (GM and no GM), significant reductions in postoperative medical complications and comorbid conditions (in total 49.5% vs. 71.0%, P<0.001) and mortality (4.7% vs. 7.7%, P<0.01) occurred and rehospitalization to medical wards within 6 months decreased (28% vs. 7.6%). However, no differences were observed in median length of hospital stay (10.8 vs. 11.0 days) or in discharge destination. Antiosteoporotic treatment (12% to 69%) and specific thromboprophylaxis (63% to 94%) increased in the GM period.

CONCLUSIONS

Orthopedic-geriatric cocare for the older patients with HF was associated with significant reductions in morbidity and mortality, and increases in optimal postoperative care. Options for further improvement of orthopedic-GM cocare need to be investigated.

Does anterior cruciate ligament reconstruction restore normal knee kinematics?

This prospective study used magnetic resonance imaging to record sagittal plane tibiofemoral kinematics before and after anterior cruciate ligament reconstruction using autologous hamstring graft. Twenty patients with anterior cruciate ligament injuries, performed a closed-chain leg-press while relaxed and against a 150 N load. The tibiofemoral contact patterns between 0° to 90° of knee flexion were recorded by magnetic resonance scans. All measurements were performed pre-operatively and repeated at 12 weeks and two years.

Following reconstruction there was a mean passive anterior laxity of 2.1 mm (sd 2.3), as measured using a KT 1000 arthrometer, and the mean Cincinnati score was 90 (sd 11) of 100. Pre-operatively, the medial and lateral contact patterns of the injured knees were located posteriorly on the tibial plateau compared with the healthy contralateral knees (p = 0.014), but were no longer different at 12 weeks (p = 0.117) or two years postoperatively (p = 0.909). However, both reconstructed and healthy contralateral knees showed altered kinematics over time. At two years, the contact pattern showed less posterior translation of the lateral femoral condyle during flexion (p < 0.01).

Preliminary assessment of perchlorate in ecological receptors at the Longhorn Army Ammunition Plant (LHAAP), Karnack, Texas

There have been increasing human health and ecological concerns about ionic perchlorate (ClO4-) since it was detected in drinking water sources in 1997. Perchlorate is known to affect thyroid function, causing subsequent hormone disruption and potential perturbations of metabolic activities. According to current estimates, perchlorate is found in the surface of groundwater of 14 states, including Texas. Longhorn Army Ammunition Plant, located in east central Texas, was a facility historically associated with perchlorate-containing propellants and rocket motors. Subsequently, perchlorate contamination in ground and surface waters at the facility has been reported. Soil, sediment, water, vegetation, and animal tissue samples were collected from several locations within the plant for a preliminary site assessment of perchlorate contamination. Perchlorate concentrations ranged from 555-5,557,000 ppb in vegetation, 811-2038 ppb in aquatic insects, below detection limits (ND) to 207 ppb in fish, ND-580 ppb in frogs, and ND-2328 ppb in mammals. Consistent with our hypothesis, aquatic organisms inhabiting perchlorate-contaminated surface water bodies contained detectable concentrations of perchlorate. Additionally, terrestrial organisms were exposed through pathways not necessarily related to contaminated surface waters. Therefore, these data demonstrate that aquatic and terrestrial species are exposed to perchlorate in the environment. To our knowledge, this represents the first incidence of perchlorate exposure among wild animals reported in the scientific literature.

Catheter ablation in the elderly in the United States: use in the Medicare population from 1991 to 1998

The safety and efficacy of catheter ablation for the treatment of drug refractory cardiac arrhythmias is well established in young patients. Little is known about its effectiveness or use in the elderly. We determined trends in the use of catheter ablation in the United States Medicare population. Data were obtained from the approximately 30 million patients covered each year by Medicare's fee-for-service program of the Health Care Financing Administration of the Department of Health and Human Services. From 1991 to 1998, Medicare's fee-for-service beneficiaries covered 80%-93% of all adults > 65 years old in the United States. All catheter-based ablative procedures performed in this population were identified through the use of the Current Procedural Terminology codes 93650, 93651, and 93652. Use rate per 1 million beneficiaries grew from 33 in 1991 to 603 in 1998. While during this 7-year period the Medicare fee-for-service population decreased by 8%, ablations increased 16-fold (1,608%). The use of catheter ablation in the older American grew exponentially during the 1990s. Further research is needed to determine the optimal use of this potentially curative technique in the elderly.

Incidence and predictors of atrial flutter in the general population

OBJECTIVES

The goal of our study was to determine the incidence and predictors of atrial flutter in the general population.

BACKGROUND

Although atrial flutter can now be cured, there are no reports on its epidemiology in unselected patients.

METHODS

The Marshfield Epidemiological Study Area (MESA), a database that captures nearly all medical care among its 58,820 residents was used to ascertain all new cases of atrial flutter diagnosed from July 1, 1991 to June 30, 1995. To identify predisposing risk factors, we employed an age- and gender-matched case-control study design using eight additional variables.

RESULTS

A total of 181 new cases of atrial flutter were diagnosed for an overall incidence of 88/100,000 person-years. Incidence rates ranged from 5/100,000 in those <50 years old to 587/100,000 in subjects older than 80. Atrial flutter was 2.5 times more common in men (p < 0.001). The risk of developing atrial flutter increased 3.5 times (p < 0.001) in subjects with heart failure and 1.9 times (p < 0.001) for subjects with chronic obstructive pulmonary disease. Among those with atrial flutter 16% were attributable to heart failure and 12% to chronic obstructive lung disease. Three subjects (1.7%) without identifiable predisposing risks were labeled as having "lone atrial flutter."

CONCLUSIONS

This study, the first population-based investigation of atrial flutter, suggests this curable condition is much more common than previously appreciated. If our findings were applicable to the entire U.S. population, we estimate 200,000 new cases of atrial flutter in this country annually. At highest risk of developing atrial flutter are men, the elderly and individuals with preexisting heart failure or chronic obstructive lung disease.

Gastric damage in the rat with nitrogen-containing bisphosphonates depends on pH

BACKGROUND

The use of nitrogen-containing bisphosphonates (N-BPs) has been reported to be associated with gastrointestinal intolerance. The fasted, indomethacin-treated rat provides a model for assessing the gastrointestinal effects of these compounds.

AIMS

The aims of this study were to elucidate the effect of pH on N-BP-induced gastric damage, and to evaluate the structure-activity relationship between N-BP anti-resorptive and gastric effects.

METHODS

Fasted rats were dosed concomitantly with indomethacin (40 mg/kg, subcutaneously) and an N-BP (pamidronate, alendronate, or risedronate at 150 or 300 mg/kg, orally), with the N-BP dosing solutions adjusted to pH 2, 4 or 7. The aminopentane and aminohexane N-BPs (150, 225 or 300 mg/kg, orally) were only tested at pH 4 only.

RESULTS

Nitrogen-containing bisphosphonate-induced gastric damage was pH-dependent, with increased damage at increasing pH.

CONCLUSIONS

Gastric damage potential did not correlate with bone anti-resorptive effects, and the more potent anti-resorptive N-BPs were not necessarily more damaging to the stomach.

Medium-term results of a mobile bearing total knee replacement

Mobile bearing total knee arthroplasty kinematically allows the advantages of large and congruent surface contact and low contact pressures, while preserving flexion, extension, and rotation in knee motion. In allowing for these degrees of freedom, the interface between bone and component also is protected from high stress. The Self Aligning I total knee arthroplasty initially was implanted in patients after its development at the authors' institution in 1990. Between 1990 and 1994, 141 patients with osteoarthritis of the knee underwent 172 total knee replacements using this system. At average followup of 5.6 years (range, 5-8 years), clinical results using this system showed a 94% satisfaction rate (good or very good). Two revision surgeries have been performed for polyethylene wear, with none of the remaining knees showing evidence of discernible wear. Complications included four cases of deep infection, four cases where a press fit femoral component failed (nonporous coated) and the patients required revision surgery, four traumatic fractures (three patellar and one supracondylar), one popliteal artery occlusion, and one revision for stiffness. Three patients required manipulation under anesthesia for arthrofibrosis. Kaplan-Meier survival curves show the probability of survival to be 91.7%, with revision surgery for any reason as an end point, and 98.8% for revision surgery because of polyethylene wear as an end point. Following the initial learning curve with this prosthesis, the medium term results using this system show maintenance of clinical success. No progressive evidence of polyethylene wear with time has been found, supporting the concept of mobile bearing arthroplasty in extending the service life of total knee arthroplasty.

Popliteal vessels in knee surgery. A magnetic resonance imaging study

Popliteal artery injury during surgery of the knee is rare but can have devastating consequences. The position of knee flexion has been thought to be protective for the popliteal artery, allowing it to fall back from the knee joint. No prior study has provided in vivo cross sectional evidence of the behavior of the popliteal vessels during knee flexion with the effect of gravity. Magnetic resonance imaging was used in nine volunteers to measure the distance of the popliteal artery and veins from the posterior proximal tibia at two levels corresponding to the levels of osteotomy in total knee arthroplasty and in high tibial osteotomy. Scans were taken with the knee in full extension and at 90 degrees flexion with the patient in the supine position, allowing for the effect of gravity. Considerable variation in behavior of the vein and the artery was observed at the high tibial osteotomy cross sectional level and the total knee arthroplasty cross sectional level. In two knees at the high tibial osteotomy cross sectional level and in two knees at the total knee arthroplasty cross sectional, level the artery moved closer to the posterior tibia with knee flexion. Even with the effect of gravity included, knee flexion does not guarantee removal of the popliteal vessels from potential harm during surgery of the knee.

The influence of weight-bearing on the measurement of polyethylene wear in THA

We have studied the influence of weight-bearing on the measurement of wear of the polyethylene acetabular component in total hip arthroplasty using two techniques. The measured vertical wear was significantly greater when radiographs were taken weight-bearing rather than with the patient supine (p = 0.001, method 1; p = 0.007, method 2). Calculations of rates of linear wear of the acetabular component were significantly underestimated (p < 0.05) when radiographs were taken supine. There are two reasons for this. First, a change in pelvic orientation when bearing weight ensures that the thinnest polyethylene is brought into relief, and secondly, the head of the femoral component assumes the position of maximal displacement along its wear path. Interpretation of previous studies on both linear and volumetric polyethylene wear in total hip arthroplasty should be reassessed in the light of these findings.

The influence of weight-bearing on the measurement of polyethylene wear in THA

We have studied the influence of weight-bearing on the measurement of wear of the polyethylene acetabular component in total hip arthroplasty using two techniques. The measured vertical wear was significantly greater when radiographs were taken weight-bearing rather than with the patient supine (p = 0.001, method 1; p = 0.007, method 2). Calculations of rates of linear wear of the acetabular component were significantly underestimated (p < 0.05) when radiographs were taken supine. There are two reasons for this. First, a change in pelvic orientation when bearing weight ensures that the thinnest polyethylene is brought into relief, and secondly, the head of the femoral component assumes the position of maximal displacement along its wear path. Interpretation of previous studies on both linear and volumetric polyethylene wear in total hip arthroplasty should be reassessed in the light of these findings.

Safe removal of massive intrapelvic cement using ultrasonic instruments

The extraction of massive intrapelvic deposits of cement in revision total hip arthroplasty presents the surgeon with a philosophical dilemma and a technical challenge. The cement is difficult to remove because of the disparity between the size of the cement mass and the defect in the acetabulum. In addition, the cement mass lies close to major intrapelvic organs, and the use of force applied with sharp cement-removing instruments poses a danger to these structures. We report on the ultrasonic technique of cement removal used to extract a massive intrapelvic cement deposit safely.

Avulsion fracture of the ischium following complex total hip arthroplasty: an unusual cause of hip pain

Total hip arthroplasty in the high riding dislocated hip is a technically difficult undertaking, with major reconstruction required on both the acetabular and femoral sides. With reconstruction at a near-anatomic hip center, reduction of the arthroplasty is difficult because of the long-standing limb shortening. The major block to reduction is tension of the soft tissues, particularly the hamstrings. We report a case of ischial tuberosity avulsion fracture following such a complex reconstruction despite femoral shortening subtrochanteric osteotomy. This illustrates the importance of the hamstring group in maintaining the dislocation and emphasizes the need to prevent overtension of the soft tissues in such complex reconstructive procedures.

Results of revision total knee arthroplasty in the face of significant bone deficiency

The successful approach to the failed knee with bone deficiency is dependent upon thorough planning prior to surgery in order to have the resources available in terms of adequate bone allograft and suitable revision implants. The approximate size of bone stock deficiency can be calculated from preoperative radiographs and similarly ligamentous incompetence can often be diagnosed clinically prior to surgery. Smaller defects of up to 1 to 1.5 cm in depth and localized in the main to a single side of the tibial plateau or to a single femoral condyle can be dealt with using smaller grafts that may be local autograft or allograft, or modular wedges. Larger tibial defects can be compensated for using conventional revision systems by thicker polyethylene and augmented baseplates, but once the flexion-extension gap reaches approximately 40 mm this is no longer possible and structural graft or customized componentry becomes necessary. Femoral defects larger than about 1 cm that cannot be made up by augments necessitate grafting. The need to use a large proximal tibial allograft also may dictate the operative approach used to expose the joint, especially in the situation of a multiply-operated tight knee. In such cases the use of a quadriceps turndown may be more advisable than the use of a tibial tubercle osteotomy as the osteotomy may well not have an adequate bed to heal to following the reconstruction. Several series have reported cases of patellar tendon avulsion and the clinical results following this complication usually are not satisfactory. Preoperatively it is important to identify, if possible, the case that is likely to require a more extended approach because of a tight soft tissue envelope. The reports of results of series of revision total knee arthroplasty in the setting of significant bone loss are at present confined to short-term followup. The clinical results of these series are satisfactory at this early point in time, but decision regarding the durability of reconstructions requiring major structural allografting awaits longer-term study. Of concern is the devastating complication of infection following such revision surgery, the risk of which is amplified in the setting of prior infection. In addition, the long-term viability of major structural grafts in the setting of loading is uncertain as the risk of graft collapse in the process of incorporation is not known. Notwithstanding these concerns, major grafting is sometimes the only recourse to achieve satisfactory revision of a failed arthroplasty. The use of such major grafts is therefore cautiously supported and because of the risks inherent in such surgery we believe that such surgery should be carried out in the setting of specialist interest units.

Paroxysmal supraventricular tachycardia in the general population

OBJECTIVES

We sought to determine the epidemiology and clinical significance of paroxysmal supraventricular tachycardia (PSVT) in the general population.

BACKGROUND

Current knowledge of PSVT has been derived primarily from otherwise healthy patients referred to specialized centers.

METHODS

We used the resources of the Marshfield Epidemiologic Study Area, a region covering practically all medical care received by its 50,000 residents. A review of 1,763 records identified prevalent cases as of July 1, 1991 and all new cases of PSVT diagnosed from that day until June 30, 1993. A mean follow-up period of 2 years was completed in all incident patients. Patients without other cardiovascular disease were labeled as having "lone PSVT."

RESULTS

The prevalence was 2.25/1,000 persons and the incidence was 35/100,000 person-years (95% confidence interval, 23 to 47/100,000). Other cardiovascular disease was present in 90% of males and 48% of females (p = 0.0495). Compared with patients with other cardiovascular disease, those with lone PSVT were younger (mean 37 vs. 69 years, p = 0.0002), had a faster PSVT heart rate (mean 186 vs. 155 beats/min, p = 0.0006) and were more likely to have their condition first documented in the emergency room (69% vs. 30%, p = 0.0377). The onset of symptoms occurred during the childbearing years in 58% of females with lone PSVT versus 9% of females with other cardiovascular disease (p = 0.0272).

CONCLUSIONS

There are approximately 89,000 new cases/year and 570,000 persons with PSVT in the United States. In the general population, there are two distinct subsets of patients with PSVT: those with other cardiovascular disease and those with lone PSVT. Our data suggest etiologic heterogeneity in the pathogenesis of PSVT and the need for more population-based research on this common condition.

Infections with nonthoracotomy implantable cardioverter defibrillators: can these be prevented? Endotak Lead Clinical Investigators

Nonthoracotomy ICDs are believed to be the best therapeutic modality for treatment of life-threatening ventricular arrhythmias. Little is known about the risk of infection with initial implantation of these devices. We studied the incidence, clinical characteristics, and risk factors associated with infections in 1,831 patients with nonthoracotomy ICD from the Endotak-C nonthoracotomy lead registry of Cardiac Pacemakers, Inc. A transvenous lead was implanted in 950 patients (51.9%) and a combination transvenous plus subcutaneous patch was used in 881 patients (48.1%). Nine preselected data variables were studied, and all investigators identified as having patients with infections were personally contacted. Infections occurred in 22 (1.2%) of 1,831 patients receiving this nonthoracotomy ICD system. The mean time to infection was 5.7 +/- 6.5 months (range 1-25 months). Staphylococci were isolated in 58% of patients with reported infection. The presence of a subcutaneous defibrillator patch system was associated with the development of infection. Six of 950 patients (0.63%) with a totally transvenous lead system developed infection versus 16 of 838 (1.9%) patients with a transvenous lead plus subcutaneous patch system configuration (P = 0.015, Chi-square test), with an unadjusted estimated odds ratio of 3.06 (CI 1.19-7.86). The risk of infection encountered with the nonthoracotomy ICD is low, estimated from our data to be 1.2%. Placement of a subcutaneous defibrillator patch appears to be an independent risk factor for development of infection.

Incipient compartment syndrome of the thigh following total knee arthroplasty

Compartment syndrome of the thigh is in itself a rarity because of the large size of the compartment and the relatively high compliance of the thigh which allows accommodation to volume changes due to hematoma or tissue edema. Most cases have been reported in association with impact trauma to the lower extremity or in association with crush syndrome. A previously unrecognized complication of total knee arthroplasty where an incipient compartment syndrome developed in the thigh extensor compartment is reported.

Nonclinical model for assessing gastric effects of bisphosphonates

Gastrointestinal intolerance has been associated with amino bisphosphonate therapy in the clinic. The objective of this study was to develop a model for assessing bisphosphonate-induced gastric damage that may aid in the development of future bisphosphonate therapies. Rats were dosed concomitantly with indomethacin (40 mg/kg, subcutaneously) and an amino or pyridinyl bisphosphonate (orally at. 150, 225 or 300 mg/kg). The bisphosphonates studied were pamidronate and alendronate (primary amino bisphosphonates) and risedronate and NE-97221 (pyridinyl bisphosphonates). Macroscopically, alendronate induced significantly (P < 0.05) more antral damage (both lesion length and number) than pamidronate and risedronate at 225 and 300 mg/kg, and more than NE-97221 at 300 mg/kg. NE-97221 induced significantly more antral damage (lesion length) than risedronate at 225 mg/kg and a greater number of lesions compared to pamidronate and risedronate at 225 and 300 mg/kg. The model was validated histologically, and macroscopic findings correlated with histologic evidence of antral mucosal necrosis and inflammatory infiltration of the lamina propria. The calcium chelators EGTA and EDTA did not induce gastric damage in this model when dosed according to the same protocol as the nitrogen-containing bisphosphonates. This suggests that calcium chelation does not account for the gastric effects in this model. The fasted, indomethacin-treated rat provides a novel nonclinical model to assess gastric effects of bisphosphonates, which may aid in the development of future bisphosphonate therapies. These data suggest that when expressed on an actual or anticipated clinical dose basis for osteoporosis (pamidronate, 150 mg; alendronate, 5-10 mg; risedronate and NE-97221, 5 mg), primary amino bisphosphonates may have a greater potential for inducing gastric damage than do pyridinyl bisphosphonates.

The ferret as a small animal model with BMU-based remodeling for skeletal research

The need exists for a small animal model with bone metabolic unit (BMU)-based remodeling to mimic the bone loss found in postmenopausal women. The purpose of this investigation was to evaluate the ferret as a potential model for skeletal research. Specifically, we determined whether the ferret: 1) exhibits evidence of BMU-remodeling, 2) has a skeletal response to parathyroid hormone (PTH) similar to other remodeling species, and 3) loses bone in response to reduced estrogen levels.

METHODS

Using three sets of experiments, we determined the response of female ferrets to ovariectomy/light cycle manipulation or to administration of PTH. Scanning electron microscopy, light microscopy, determination of estrogen levels and/or single-photon absorptiometry (SPA) were used for evaluation.

RESULTS

The ferret was found to exhibit BMU-based remodeling, and may therefore provide a small animal remodeling species for skeletal research. Ferrets reach skeletal maturity between four and seven months of age as evidenced by closure of the growth plate and maturation of trabecluae from thin rods to thick rods and plates. PTH treatment resulted in a marked increase in bone mass accompanied by the PTH-induced tunneling phenomenon known to occur in dogs and humans but not rats. The response to PTH supports the use of the ferret in studies of bone anabolic agents. Bone mass in the proximal tibia was significantly reduced when estrogen depletion was induced by either bilateral ovariectomy or short light/dark cycles (8 hour light, 16 hour dark). Maintenance of intact ferrets under short-light conditions mimiced ovariectomy in terms of serum estrogen levels, uterine weights, and tibial BMD.(ABSTRACT TRUNCATED AT 250 WORDS)

[Advances in the treatment of tachiarrhythmias: role of nonpharmacological methods]

Nonpharmacological methods are a novel therapeutic option for tachiarrhythmias. Transcatheter ablation or surgery can cure many arrhythmias, avoiding the collateral effects of antiarrhythmic drugs. Likewise, implantable defibrillators, have changed life expectancy of patients with high risk arrhythmias or sudden death survivors. However, the high cost and sophistication of these methods, preclude their widespread use, thus limiting the number of patients that can be benefited. This article reviews the main nonpharmacological techniques for treatment of arrhythmias, their results and complications.

Risedronate treatment does not increase microdamage in the canine femoral neck

Cortical and trabecular bone from the femoral neck of 24 adult female beagle dogs was examined for microdamage following 2 years of treatment with risedronate (NE-58095). Specimens of the femoral neck, sectioned between the femoral head and the intertrochanteric groove, were bulk stained in 1% basic fuchsin in graded alcohols and embedded in methylmethacrylate. Five transverse sections of 100 microns from each specimen were examined for microdamage and measurement of cortical and trabecular area, and three sections from each specimen were measured for calculation of trabecular and cortical bone activation frequency (Ac.f) and bone formation rate (BFR/BV) in the superior and anterior regions of the femoral neck. Although no statistical differences were observed among groups for numerical density or length of microcracks, Kruskal-Wallis analysis showed differences among groups for both cortical and trabecular bone area (p < 0.05). Ac.f was significantly lower in both cortical bone (p < 0.05) and trabecular bone (p < 0.005) of the femoral neck at all dosage levels. No significant difference was observed among groups for trabecular mean wall thickness. The hypothesis that microdamage accumulation increases following reduction in Ac.f was not supported for the canine femoral neck in this experiment. This result could be explained by the fact that microdamage does not accumulate following treatment; that transient increases in microdamage at the beginning of the study period had been repaired; or finally, that the canine femoral neck does not reflect weight-bearing conditions of clinical relevance to humans for assessment of microdamage.

Antibiotic prophylaxis in low-risk cesarean section

This prospective study was undertaken in an effort to evaluate the role of systemic antibiotic prophylaxis in elective abdominal delivery. Eighty-two patients undergoing elective cesarean section who were not in labor and who did not have ruptured membranes were assigned on a randomized, double-blind basis to receive a three-dose perioperative course of either placebo or ampicillin. Postoperatively, patients were evaluated for the development of infection-related complications. Patients in the antibiotic group experienced less febrile morbidity, had lower fever indices and developed fewer operative-site infections than did patients in the control group. No patient in either group, however, developed a potentially life-threatening infection, and all infected patients responded promptly to parenteral antibiotic therapy. Because of the limited morbidity associated with elective cesarean section in this patient population, it is concluded that the theoretical risks of antibiotic prophylaxis outweigh the expected benefits.