Biomechanical characteristics of the human esophagus

Biochemechanical wall properties of the human esophagus were studied. A probe, with a balloon designed for simultaneous measurement of cross-sectional area and intraluminal pressure, was placed in the esophagus 30 cm from the incisors. Tone was not detected before inflation of the balloon. When the balloon was inflated stepwise with pressures up to 40 cm H₂O (30.7 mm Hg), measurement of cross-sectional area allowed calculation of distensibility and circumferential wall tension. Balloon cross-sectional area increased linearly with increased balloon pressure. Balloon distension induced contractions, both proximal to the balloon and at the site of distension, at a balloon pressure of about 15 cm H₂O (11.5 mm Hg). The cross-sectional area for the threshold for distension induced contractions was 153±12 mm² (diameter 14 mm). At the onset of these contractions, the contraction force was 15–20 cm H₂O (11.5–15.3 mm Hg) and it increased to 47–58 cm H₂O (36.1–44 mm Hg) at a balloon pressure of 20–40 cm H₂O (15.3–30.7 mm Hg). Circumferential wall tension increased with increasing intraluminal pressure in an almost exponential manner. The pressure elastic modulus increased steeply at lower balloon pressures (10–20 cm H₂O) (7.7–11.5 mm Hg), but at higher balloon pressures (20–40 cm H₂O) (15.3–30.7 mm Hg) this increase was less. The circumferential wall tension and wall stiffness of the human esophagus increased with increasing balloon pressure and cross-sectional area. When a threshold is reached, distension induced contractions both proximal and distal to the balloon and at the distension site.This work was supported by a National Institutes of Health grant DK 11242.     

Salmonid alphavirus glycoprotein E2 requires low temperature and E1 for virion formation and induction of protective immunity

Salmonid alphavirus (SAV; also known as Salmon pancreas disease virus; family Togaviridae) causes pancreas disease and sleeping disease in Atlantic salmon and rainbow trout, respectively, and poses a major burden to the aquaculture industry. SAV infection in vivo is temperature-restricted and progeny virus is only produced at low temperatures (10–15 °C). Using engineered SAV replicons we show that viral RNA replication is not temperature-restricted suggesting that the viral structural proteins determine low-temperature dependency. The processing/trafficking of SAV glycoproteins E1 and E2 as a function of temperature was investigated via baculovirus vectors in Sf9 insect cells and by transfection of CHSE-214 fish cells with DNA constructs expressing E1 and E2. We identified SAV E2 as the temperature determinant by demonstrating that membrane trafficking and surface expression of E2 occurs only at low temperature and only in the presence of E1. Finally, a vaccination-challenge model in Atlantic salmon demonstrates the biological significance of our findings and shows that SAV replicon DNA vaccines encoding E2 elicit protective immunity only when E1 is co-expressed. This is the first study that identifies E2 as the critical determinant of SAV low-temperature dependent virion formation and defines the prerequisites for induction of a potent immune response in Atlantic salmon by DNA vaccination.     

Use of the flexible bronchoscope and Infrared Red Intubation System in a known difficult airway in the intensive care unit

This case report describes a patient in the ICU in need of urgent intubation, for whom video laryngoscope‐guided intubation had previously failed. The Infrared Red Intubation System (IRRIS) may enhance the chance of successful flexible bronchoscope intubation, especially when performed by non‐expert anesthesiologists.     

A whole genome association study in Icelandic multiple sclerosis patients with 4804 markers

Multiple sclerosis (MS) is a demyelinating disorder of the central nervous system (CNS) with a complex genetic background. Here we use a genome-wide association strategy with 4804 microsatellite markers successfully typed in separately pooled DNA from 200 patients and 200 controls. A total of 91 markers showed evidence of association. When compared to our in-house physical map of the genome, six 2-Mb regions containing at least two of these markers were detected. Of those, three regions have one or more markers among the 20 most strongly associated: chromosomes 3q25, 6p21.3 (the MHC region) and 19q13.     

A whole genome association study in multiple sclerosis patients from north Portugal

Genetic factors are known to influence susceptibility to multiple sclerosis (MS) but the genes involved are largely undefined. Here, we report an association study based on 200 patients and 200 controls from the Porto region in Portugal. A total of 3974 markers were successfully typed from which we have identified 46 markers showing evidence of association. When compared to a physical map three regions were found with two of these markers less than 1.5 Mb apart: chromosomes 6p21.3 (the MHC region), 6q14.1 and 7q34.     

Clinical Characteristics and Outcomes in Patients with Advanced Rectal Cancer: A National Prospective Cohort Study

Purpose At the time of diagnosis, approximately one third of patients with rectal cancer present with advanced disease. In this study we focus on a group of patients with primary advanced rectal cancer considered as not operable. We address various clinical aspects relevant for decision-making in a group of patients in need of palliative care. Methods Between January 1997 and December 2001, 4831 consecutive patients with rectal cancer were prospectively registered in the Norwegian Rectal Cancer Registry. In this national population-based cohort, 386 patients (8 percent) without surgical interventions were identified. These patients comprise the study population. Clinical characteristics and survivals were addressed. Results Patients not surgically treated were significantly older compared with other treatment groups (median age, 80 years; interquartile range, 72–86 vs. median age, 71 years; interquartile range, 62–79 years) (P<0.001). Median survival time was 4.5 (range, 3.5–5.4) months, regardless of age, gender, or hospital category. Patients who received radiotherapy had a significantly increased survival (P<0.001) compared with patients not treated with radiation, with a median survival time of 10.2 (range, 7.3–12.1) months vs. 2.8 (range, 2.1–3.6) months, respectively. Use of chemotherapy was not associated with improved survival. In multivariate analysis, only stage of disease and radiotherapy were independent predictors of better survival. Conclusion Higher age and comorbidity seem to influence choice of treatment in this subgroup of patients with advanced rectal cancer disease. In nonsurgically treated patients, radiotherapy was associated with an improved survival. Our prospective, population-based cohort study emphasizes the dismal prognosis of these patients, which also should challenge our efforts and clinical approaches in palliative care. Dr. H. K. Sigurdsson, M.D., is a Reseach Fellow sponsored by the Western Norwegian Regional Health Authorities (Project No. 911158). Reprints are not available.     

Eccentric treatment for patellar tendinopathy: a prospective randomised short-term pilot study of two rehabilitation protocols

Objective

To compare the efficacy and safety of two eccentric rehabilitation protocols for patients with symptomatic patellar tendinopathy. A new eccentric overload training device was compared with the present standard eccentric rehabilitation programme on a decline board.

Design

Prospective, randomised clinical trial.

Setting

Sports rehabilitation clinic, university sports laboratory, supplemented with home exercises.

Patients

20 competitive and recreational athletes, all with clinical diagnosis of patellar tendinopathy, verified by MRI or ultrasound imaging.

Interventions

A 12‐week rehabilitation period, either with bilateral eccentric overload strength training using the Bromsman device twice a week or with unilateral eccentric body load training using a decline board twice a week, supplemented with daily home exercises.

Outcome measures

The primary outcome was pain and function, assessed by the Swedish Victorian Institute of Sport Assessment for Patella (VISA‐P) score. Secondary outcome measures were isokinetic muscle torque, dynamic function and muscle flexibility, as well as pain level estimations using visual analogue scale (VAS). Side effects were registered.

Results

Both treatment groups improved in the short term according to the VISA‐P scores during the 12‐week rehabilitation period. However, there were no significant differences between the groups in terms of pain and function. After a 3‐month rehabilitation period, most patients could be regarded as improved enough to be able to return to training and sports. No serious side effects were detected in either group.

Conclusion

In patients with patellar tendinopathy pain, two‐legged eccentric overload training twice per week, using the new device (Bromsman), was as efficient and safe as the present standard daily eccentric one‐legged rehabilitation‐training regimen using a decline board.Proximal patellar tendon pain (patellar tendinopathy) occurs typically in sports characterised by high demands on force and power of the leg extensor muscles, such as basketball, volleyball, tennis and soccer. Controlled eccentric strengthening of the muscle–tendon complexes involved seems to be important for successful rehabilitation.^1,2,3,4,5 Eccentric squat training on a decline board has been shown to have a superior therapeutic effect in reduction of pain compared with squatting on a flat surface.⁶ One‐legged squatting, using the decline board, resulted in encouraging results with, for example, earlier return to a functional level of sport.^7,8 By contrast, Visnes et al⁹ showed no significant improvements of eccentric training on patellar tendinopathy among volleyball players when instituted during the playing season.Previous research suggests that the efficacy of eccentric squatting rehabilitation may be correlated with the load applied to the quadriceps muscle. The aim of the present prospective randomised short‐term study was to evaluate and compare clinical outcomes in terms of knee pain and function after eccentric training, using either a novel eccentric overload training device (Bromsman, Lidingö, Sweden)¹⁰ or the current standard programme of one‐leg squatting exercises.¹¹