Stability of nodal quasiparticles in superconductors with coexisting orders

We establish a condition for the perturbative stability of zero energy nodal points in the quasiparticle spectrum of superconductors in the presence of coexisting commensurate orders. The nodes are found to be stable if the Hamiltonian is invariant under time reversal followed by a lattice translation. The principle is demonstrated with a few examples. Some experimental implications of various types of assumed order are discussed in the context of the cuprate superconductors.

Dynamical layer decoupling in a stripe-ordered high-T(c) superconductor

In the stripe-ordered state of a strongly correlated two-dimensional electronic system, under a set of special circumstances, the superconducting condensate, like the magnetic order, can occur at a nonzero wave vector corresponding to a spatial period double that of the charge order. In this case, the Josephson coupling between near neighbor planes, especially in a crystal with the special structure of La(2-x)Ba(x)CuO(4), vanishes identically. We propose that this is the underlying cause of the dynamical decoupling of the layers recently observed in transport measurements at x = 1/8.

Establishing standardised methods for comparing aqueous droplet inhalers

Aerosol inhalers are widely used to deliver drug directly to the respiratory system in patients with respiratory disease. Currently available nebulisers only deliver a proportion of the loaded or charged dose to the patient. The proportion of the charged dose received by the patient can be considered as the inhalable dose and is that part of the dose generated during inhalation and breathed in by the patient. As such, it is important to fully characterise the performance of new nebuliser brands to assess the proportion of the charged dose actually delivered to the patient. Despite the large variety of nebulisers, driver units and formulations currently on the market, often little is known about the performance of new nebulisers in terms of inhalable dose under a variety of breathing patterns and with different drug formulations. The results presented here highlight the variation in performance in terms of inhalable dose and droplet distribution of a breath-enhanced jet nebuliser when tested with a number of formulations and under different breathing patterns. Based on the results presented here we propose that a standard protocol for evaluating the performance of established and developmental nebulisers should include breathing patterns appropriate to the intended use and a variety of test formulations to capture those currently available for nebulisation.

In vitro comparison of nebulised budesonide (Pulmicort Respules®) and beclomethasone dipropionate (Clenil® per Aerosol)

This study compared the in vitro performance of two inhaled corticosteroid products for nebulisation, Pulmicort Respules(budesonide 0.5 mg/mL) and Clenil) per Aerosol (beclomethasone dipropionate (BDP) 0.4 mg/mL). Each product was used in combination with three different nebulisers (2 mL/test, 5 min run time) and the dose to the lungs was determined according to standard methods. The shape of the suspended particles in each product was studied using scanning electron microscopy (SEM). Overall, a higher fine particle dose was achieved with Pulmicort Respules versus Clenil per Aerosol, with estimated dose to the lungs of 8-14 and 3-6% of nominal dose, respectively. SEM showed that budesonide particles were small, typically approximately 2-3 microm in diameter, whereas those of BDP were needle-shaped and up to approximately 10 microm long. The more favourable particle shape and size of suspended budesonide may explain the higher fine particle dose with Pulmicort Respules versus Clenil per Aerosol.

[Total mesorectal excison and colonic-J-pouch-anal anastomosis in the therapy of low rectal carcinoma--results in 116 patients]

BACKGROUND

Total mesorectal excision with coloanal anastomosis has been accepted as standard therapy of low rectal carcinoma. Interposition of colonic J-pouch improved the functional results and was associated with better postoperative quality of life. In this study our own results are evaluated.

METHODS

Between 1. 7. 1999 and 30. 6. 2001 116 patients underwent total mesorectal excision with coloanal anastomosis and colonic J-pouch interposition. Thirty-eight patients (32.9 %) with uT3-carcinoma received preoperative adjuvant short-time irradiation with 5 x 5 Gy and seven patients (6.0 %) with local non resectable cancer conventional radiochemotherapy with 50.4 Gy. A protective stoma was constructed in 56 patients (48.3 %). Six patients (5.2 %) received secondary stoma due to anastomotic complications.

RESULTS

A clinically relevant insufficiency of the anastomosis occurred in eight patients (6.9 %). Three patients needed a secondary laparotomy for local peritonitis. Fecal diversion was constructed secondarily in four patients due to pouchvaginal fistula and in one patient for ischiorectal abscess one year after the first operation. Six patients revealed small fistulas in the radiological examination without clinical consequences. Five patients with primary fecal diversion showed pouchvaginal fistulas. The over-all anastomotic complication rate was 16.4 %. The follow-up demonstrated already in the first year after surgery good functional results with satisfying anorectal continence. Only nine patients complained of intermittent incontinence for solid stool. No patient needed a definitive stoma due to anastomotic complications. One patient developed a small anastomotic tumor recurrence one year after surgery. He could be cured by abdomino-perineal excision.

CONCLUSIONS

Our results confirm the importance of total mesorectal excision as standard therapy for low rectal carcinoma. Good functional results can be obtained already in the early postoperative period by colonic J-pouch interposition.

[Anal sphincter-CT and dorsal sphincteropexy - a new approach in therapy of obstructive defecation disorder]

The dysplasia of anal sphincter represents an obstructive defecation disorder. The disease is known as "anterior displaced anus" in pediatric surgery. An anorectal malformation with missing dorsal osseous fixation of the sphincter complex is the underlying cause. Beyond clinical symptoms and examination result (anterior displaced anus with palpable dorsal gap) the defect can be visualized by computered tomography. A surgical correction is possible by the simple intervention of dorsal sphincteropexy. In our trial with 48 patients (male n = 12, female n = 36, mean age 51 +/- 17 years, follow-up in 39 patients) a significant improvement of defecation could be achieved in 46 % of the patients. In correlation to a good clinical outcome a significant reduction in the defecation score was observed. 10 % of the patients had only small changes in symptoms. However, the proportion of dissatisfied patients was relatively high with 44 %. In this group patients with long-standing chronic constipation and laxative abusus were found more often and the rate of previous anal or abdominal surgery was quite higher. Dissatisfied patients showed a higher variation in symptoms of pelvic floor disorders (e. g. anal pain syndrome) besides the rectal evacuation disorder. In addition to the heterogenity of symptoms chronic alterations of pelvic floor structures might create worse results in patients with chronic constipation. In spite of a lot of publications dealing with the functional anatomy of the pelvic floor only a few investigations on the dorsal sphincter dysplasia in patients with rectal evacuation disorder are found in the literature. Further investigations on this disorder are necessary.

X-ray diagnosis of healing fractures in rabbits

Do X-rays adequately reflect the strength of callus post fracture? Eleven rabbit tibiae were manually fractured and allowed to heal in plaster. At varying times post fracture, the rabbits were sacrificed and the tibiae were removed. AP and lateral X-rays of each tibia were obtained and shown to 27 orthopedists and radiologists who were asked to rank the bones in order of strength. The valid ranking was done using data obtained by loading the bones axially to failure in an Instron machine. Each physician's ranking was compared with that obtained from the Instron with a median correlation level p=0.0668. This implies that a physician, whether an orthopedist or radiologist, is not very reliable at determining early osseous union.

Macrophages secrete matrix metalloproteinase 9 covalently linked to the core protein of chondroitin sulphate proteoglycans

Matrix metalloproteinases (MMPs) secreted from the leukemic macrophage cell-line THP-1 have been investigated. Under serum-free conditions, this cell-line synthesizes and secretes proMMP-9, which was detected in the culture medium as a monomer of 92 kDa, and in dimeric forms, including a homodimer of approximately 225 kDa. In addition, a new heterodimer complex is described, in which proMMP-9 is covalently linked to the core protein of chondroitin sulphate proteoglycan (CSPG) through one or more disulphide bridges. After SDS-PAGE electrophoresis, at least two forms of this complex were detected, a large form in the stacking gel and a smaller form with an estimated size of 300 kDa. When the CS chains were removed by chondroitin ABC lyase treatment, heterodimers of proMMP-9/CSPG core protein of approximately 145, 127 and 109 kDa were found, based on zymography and Western blots. Since as much as 10-15 % of the total proMMP-9 secreted from THP-1 cells was covalently linked to CSPG, this association may have important implications for transport, targetting and regulation of the enzyme activity.

Deep muscle contusion complicated by myositis ossificans (a.k.a. heterotopic bone)

One muscle trauma is a common injury in contact sports. The most extensively damaged muscle is that segment closest to the underlying bone. By an unknown mechanism, this injured muscle can become transformed into heterotopic bone, a complication also called myositis ossificans. It is best managed conservately and rarely requires surgery.

Reliability and validity of the Dental Indifference Scale in a population of 18-year-olds in Norway

OBJECTIVES

The aims of this study were to estimate the reliability and validity of the Dental Indifference Scale (DIS) (Nuttall, 1996) in a population of 18-yr-olds in Norway.

METHODS

The DIS-scale was mailed to a sample of 1119 18-yr-olds in two Norwegian counties. Nearly 87% completed the questionnaire and consented to the collection of data from their dental records. Ten percent of the sample, drawn at random, was asked to complete the questionnaire a second time, after a time delay of 15 weeks (response rate 83%). The reliability estimation of the sum-scores of DIS was based on Pearson's correlation between test-retest scores and internal consistency (Cronbach's alpha). The frequency of missed appointments from age 12, recorded in the dental treatment records, was used as the validating criterion. The validity was analyzed by Pearson's correlation, and step-wise multiple regression.

RESULTS

The correlation coefficient (Pearson) for the test-retest comparison was 0.43. The correlation coefficient between the DIS-scores and the frequencies of missed dental appointments was 0.24. The Cronbach's Alpha coefficient for the eight DIS-questions was 0.35 (n=868). Only two of the eight DIS-questions entered the stepwise regression model and explained 15% of the variance of the frequency of missed appointments.

CONCLUSIONS

The Dental Indifference Scale (DIS) was found to have a low reliability and validity in this study population, and it is recommended that it should not be used without further investigation. It may be necessary to design an alternative instrument if further work into the hypothesized trait of dental indifference is to be undertaken.

Conduction defects after coronary artery bypass grafting--a disappearing problem?

BACKGROUND AND AIMS

To evaluate the incidence of conduction defects (CDs) following coronary artery bypass grafting (CABG) in three different patient populations, to assess the etiologic factors associated with CDs, and to find out their effect on immediate postoperative outcome of the patient.

MATERIAL AND METHODS

Three patient populations were prospectively studied: cohort A consisted of 180 CABG-patients operated between 1990-91, cohort B of 100 patients operated during the year 1993 and cohort C of 118 patients operated from April 1997 to June 1997. Cold crystalloid cardioplegia was used throughout the study years. In the first cohort A, two separate cavae were cannulated and clamped, venting through the right upper pulmonary vein was used, iced cold saline was used in pericardium, and cardioplegia was given until a myocardial temperature of 10-15 degrees of Celcius was attained. In the two later cohorts, two-stage venous cannula and aortic root venting were used and cardioplegia was given only until the activity of the myocardium stopped. Proximal anastomoses were performed after aortic declamping in cohort A, and during aortic occlusion in the two later cohorts.

RESULTS

The incidence of permanent CDs in cohort A was 36%, in cohort B 5% and in cohort C 1%. Permanent atrioventricular (AV-) and left-sided blocks disappeared first. Left main coronary artery stenosis and low myocardial temperatures were associated with CDs. Patients with permanent CDs had more often low cardiac output after the operation, their values of cardiac enzymes were higher, and they had more often postoperative infarction than patients without CDs.

CONCLUSIONS

The disappearance of all long lasting AV- and left-sided blocks simultaneously with decreasing plasma levels of cardiac enzymes is evidence that protection of both conduction tissue and myocardium had considerably improved in the two later cohorts. Giving cardioplegia in smaller amounts and more often at the same time when raising the general temperature during perfusion were the main reasons for the disappearance of postoperative CDs.

Factors related to missed and cancelled dental appointments among adolescents in Norway

The aim of this study was to explore possible explanatory factors related to high frequency of missed/cancelled dental appointments during the age group 12-18 yr. A total of 754 20 yr olds completed a questionnaire including variables measuring demographics, occupation (school/job), attendance pattern, attitudes to dentists, opinion about importance of dental treatment, and the psychometric scales Dental Fear Scale (DFS), Dental Beliefs Survey (DBS) and Geer Fear Scale (GFS). Based on written consents, the following data were recorded from their dental records: the total number of scheduled appointments, the number of missed and cancelled appointments and the individual caries experience of those in the age group 12-18 yr. A total of 124 subjects who had missed/cancelled 20% or more of their dental appointments during this age were defined as a target group. A stepwise regression model indicated that the likelihood of being included in the target group increased by a factor of 6.0 if the subject had forgotten dental appointments during the last 5 yr, by a factor of 3.5 for working or without specified occupation (as opposed to attending school), by a factor of 2.7 for negative beliefs of dentists, and by a factor of 2.1 for high caries experience.

Safety and efficacy of dynamic graciloplasty for fecal incontinence: report of a prospective, multicenter trial. Dynamic Graciloplasty Therapy Study Group

PURPOSE

Dynamic graciloplasty has been used for intractable fecal incontinence, and good results have been reported. The aim of this study was to assess prospectively the safety and efficacy of dynamic graciloplasty for intractable fecal incontinence in a prospective, multicenter trial.

METHODS

A total of 123 adults were treated with dynamic graciloplasty at 20 institutions. Continence was assessed preoperatively and postoperatively by use of 14-day diaries.

RESULTS

There was one treatment-related death. One hundred eighty-nine adverse events occurred in 91 patients (74 percent). Forty-nine patients (40 percent) required one or more operations to treat complications. One hundred seventy (90 percent) events were resolved. Sixty-three percent of patients without pre-existing stomas recorded a 50 percent or greater decrease in incontinent events 12 months after dynamic graciloplasty, and an additional 11 percent experienced lesser degrees of improvement. Twenty-six percent were not improved, worsened, or exited. In patients with pre-existing stomas, 33 percent achieved successful outcomes at 12 months. This number increased to 60 percent at 18 months. Seventy-eight percent of patients had increased enema retention time, and mean anal canal pressures improved significantly at 12 months. Significant changes in quality of life were also observed.

CONCLUSIONS

Objective improvement can be demonstrated in the majority of patients with end-stage fecal incontinence treated with dynamic graciloplasty. Reduction in incontinence episodes can be correlated with improved quality of life. Adverse events are frequently encountered, but most resolve with treatment.

A mathematical model of aerosol holding chambers

A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London, Ontario, Canada), NebuChamber (Astra, Södirtälje, Sweden) and Nebuhaler (Astra) adapted for babies. The dose of fluticasone proportionate delivered by the Babyhaler (Glaxco Wellcome, Oxbridge, Middlesex, UK) was 80% of that predicted, probably because of incomplete priming of this spacer. Of the above-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were demonstrated by comparison of pressure flow curves during "inspiratory" flow with and without occluded expiratory openings. Insufficient inspiratory valves were demonstrated by comparison of "expiratory" pressure flow curves with and without occluded inspiratory openings. With children breathing through the spacers, mask pressure variations were generally on the same order as that seen with the mechanical respiratory, supporting the clinical relevance of the in vitro findings.

Dental anxiety and dental avoidance among 12 to 18 year olds in Norway

The aim of this study was to explore the prevalence and possible explanatory factors of dental avoidance due to dental anxiety among 12 to 18 year olds treated within the Norwegian Public Dental Service. A total of 754 20-yr-olds completed a questionnaire and three psychometric scales, the Dental Fear Scale (DFS), the Dental Beliefs Survey (DBS) and the Geer Fear Scale (GFS), and gave their consent to collect data from their dental records. A total of 169 subjects (22.4%) had high dental anxiety (DFS>59 or DBS>47 at age 20 yr), and 124 subjects (16.4%) had high frequency of missed/cancelled appointments (20% or more) during the period 12-18 yr. Forty-seven subjects (6.2%) fulfilling both of the above criteria constituted the dental avoidance group. An analysis using a stepwise regression model indicated that having had more than one painful or unpleasant treatment experience increased the risk of being included in the avoidance group by a factor of 10.9. Equally, adolescents who were not attending school (working or without specified occupation) increased the risk by a factor of 6.9, having a high caries experience by a factor of 5.0, and not having their dental treatment completed at the age of 18 yr by a factor of 4.4.

Synovial osteochondomatosis

Synovial osteochondomatosis is a benign, metaplastic disease of unknown etiology in which synovial tissue can differentiate into cartilage and/or bone. This cartilage and bony tissue may be attached to the synovium or may break free and become intraarticular loose bodies. The treatment of choice for this unusual condition is synovectomy, which is usually curative.

Epitope mapping of CCR5 reveals multiple conformational states and distinct but overlapping structures involved in chemokine and coreceptor function

The chemokine receptor CCR5 is the major coreceptor for R5 human immunodeficiency virus type-1 strains. We mapped the epitope specificities of 18 CCR5 monoclonal antibodies (mAbs) to identify domains of CCR5 required for chemokine binding, gp120 binding, and for inducing conformational changes in Env that lead to membrane fusion. We identified mAbs that bound to N-terminal epitopes, extracellular loop 2 (ECL2) epitopes, and multidomain (MD) epitopes composed of more than one single extracellular domain. N-terminal mAbs recognized specific residues that span the first 13 amino acids of CCR5, while nearly all ECL2 mAbs recognized residues Tyr-184 to Phe-189. In addition, all MD epitopes involved ECL2, including at least residues Lys-171 and Glu-172. We found that ECL2-specific mAbs were more efficient than NH2- or MD-antibodies in blocking RANTES or MIP-1beta binding. By contrast, N-terminal mAbs blocked gp120-CCR5 binding more effectively than ECL2 mAbs. Surprisingly, ECL2 mAbs were more potent inhibitors of viral infection than N-terminal mAbs. Thus, the ability to block virus infection did not correlate with the ability to block gp120 binding. Together, these results imply that chemokines and Env bind to distinct but overlapping sites in CCR5, and suggest that the N-terminal domain of CCR5 is more important for gp120 binding while the extracellular loops are more important for inducing conformational changes in Env that lead to membrane fusion and virus infection. Measurements of individual antibody affinities coupled with kinetic analysis of equilibrium binding states also suggested that there are multiple conformational states of CCR5. A previously described mAb, 2D7, was unique in its ability to effectively block both chemokine and Env binding as well as coreceptor activity. 2D7 bound to a unique antigenic determinant in the first half of ECL2 and recognized a far greater proportion of cell surface CCR5 molecules than the other mAbs examined. Thus, the epitope recognized by 2D7 may represent a particularly attractive target for CCR5 antagonists.

[Early postoperative complications after different methods of intestinal reconstruction in deep anterior rectum resection--a prospective study]

For the first period after low anterior resection and total mesorectal excision for rectal cancer, the colonic J-pouch is superior to the straight or lateroterminal anastomosis. Despite the simple technique and short stretch of sutures, the LTA is unsuitable due to the high postoperative morbidity and because the reconstruction functions poorly. If the expected anastomis is below 6 cm from the anal verge, i.e. 4 cm above the sphincter muscle, the colonic J-pouch is recommended.

Epidural analgesia with bupivacaine does not improve splanchnic tissue perfusion after aortic reconstruction surgery

Inadequate splanchnic tissue perfusion is relatively common during and after aortic surgery. We hypothesized that vasodilation caused by thoracic epidural analgesia improves splanchnic blood flow and tissue perfusion after aortic surgery. In this prospective, randomized, controlled study, we studied 20 patients undergoing elective aortic-femoral or aortic-iliac reconstruction surgery. Gastric and sigmoid colon mucosal PCO2 and pH were measured during surgery. An epidural bolus of bupivacaine 40 mg followed by infusion of 15 mg h-1 was started after operation in 10 patients. After operation, splanchnic blood flow and gastric and sigmoid colon mucosal PCO2 and pH were measured before and 2 h after the start of epidural analgesia. During surgery, the gastric mucosal-arterial PCO2 difference remained stable, whereas the sigmoid mucosal-arterial PCO2 difference increased during aortic clamping but returned to pre-clamping values after declamping. After operation, epidural analgesia had no effect on gastric or sigmoid mucosal-arterial PCO2 differences or on splanchnic blood flow.

Missed and cancelled appointments among 12-18-year-olds in the Norwegian Public Dental Service

The aims of this study were to evaluate the prevalence and distribution of missed and cancelled dental appointments in the Norwegian Public Dental Service during the age period from 12 to 18 yr, and to explore possible relationships with demographics and individual caries experience (DMFT). A total of 968 patients (86.5% of the sample) gave their consent to collect data from their dental records. Forty-seven % of the group had missed and 26% had cancelled one or more dental appointments. A total of 13.6% had missed more than 20% of their appointments. Missed and cancelled appointments were to a great extent related to different individuals. The frequency of individuals with missed and cancelled appointments showed an almost linear increase from age 12 to 18 yr, and the mean individual frequency increased from 1.1 to 11.8% for missed appointments and from 0.7 to 4.8% for cancelled appointments. Subjects with missed appointments had a significantly higher mean DMFT at the age of 18 compared with the rest of the group. Individuals with missed and cancelled appointments may represent a risk group for future dropout from dental care which should be further analyzed.