Search for new physics using QUAERO: a general interface to D0 event data

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ, and t t macro production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W'-->WZ. Through this interface, we make three data sets collected by the D0 experiment at square root of [s] = 1.8 TeV publicly available.

Mollusks of Manuel Antonio National Park, Pacific Costa Rica

The mollusks in Manuel Antonio National Park on the central section of the Pacific coast of Costa Rica were studied along thirty-six transects done perpendicular to the shore, and by random sampling of subtidal environments, beaches and mangrove forest. Seventy-four species of mollusks belonging to three classes and 40 families were found: 63 gastropods, 9 bivalves and 2 chitons, during this study in 1995. Of these, 16 species were found only as empty shells (11) or inhabited by hermit crabs (5). Forty-eight species were found at only one locality. Half the species were found at one site, Puerto Escondido. The most diverse habitat was the low rocky intertidal zone. Nodilittorina modesta was present in 34 transects and Nerita scabricosta in 30. Nodilittorina aspera had the highest density of mollusks in the transects. Only four transects did not clustered into the four main groups. The species composition of one cluster of transects is associated with a boulder substrate, while another cluster of transects associates with site. Two clusters were not associated to any of the factors recorded. Some species were present in previous studies but absent in 1995, while others were absent in the previous studies but found in 1995. For example, Siphonaria gigas was present in 1995 in many transects with a relatively high density, but absent in 1962, probably due to human predation before the establishment of the park. Including this study, a total of 97 species of mollusks in three classes and 45 families have been reported from Manuel Antonio National Park. Sixty-nine species are new reports for the area: 53 gastropods, 14 bivalves and 2 chitons. There are probably more species of mollusks at Manuel Antonio National Park, than the 97 reported here, because some areas have not been adequately sampled (e.g., deep environments) and many micro-mollusks could not be identified.

[Orthopedic/visceral surgery cooperation in pelvic tumors]

Co-operation between orthopaedic surgeons and visceral surgeons is required in the treatment of malignant tumours of the pelvis when the rectum or the iliac vessels are infiltrated. Such infiltration can be expected in malignancies which originate in the sacrum. Most frequently, chordomas are found in this area, that should be resected with wide surgical margins even in advanced tumours to reduce the risk of local recurrence. When resecting the sacrum, the stability of the vertebral column and the pelvis is compromised only at levels above S2. After unilateral resection of the sacral nerve roots S2-S5, there are only minor impairments of the anal and bladder sphincter control. In the case of tumour infiltration of the rectum and simultaneous resection of the sacral nerve roots, abdominoperineal extirpation of the rectum is required even when a safe margin is left between the tumour and the anal sphincter. In different studies, the 5-year survival in patients with a malignancy of the sacrum varies between 52% and 84%. In view of the rarity of these tumours, treatment should be performed only at specialized centers where co-operation is ensured.

Students' conceptual model of a good community attachment

BACKGROUND

In 1994, Manchester University Medical School introduced a new integrated curriculum using problem-based learning and which places an increased emphasis on community-based education.

AIMS

Students commonly use a particular label ("a good GP" (general practitioner)) to describe a positive experience in the community. The purpose of the study was to explore what students mean by "a good GP" and how this relates to their perceptions of the value of the community aspect of the course.

METHOD

Three single-year focus groups were run with year 3, 4 and 5 students. A model was then derived which was explored and checked against the views of a cross-year focus group.

RESULTS

A theoretical model based on student conceptualization of "a good GP" was developed. "A good GP" was found to consist of the GP as a teacher, as a role model and as an indicator of a positive learning environment. With regard to "good teacher", students felt that the GP's enthusiasm about teaching and involving the student in an active learning process was important. For "good role model", students emphasized communication skills and non-judgmental attitudes. With regard to "good learning environment", a friendly atmosphere, variety of activities, and flexibility shown by the staff of the health centre were important.

CONCLUSIONS

Students hold a complex conceptual model of "a good GP" which the label does not convey. We suggest that for evaluations of student experiences it is important to explore in depth what students mean by particular terms or labels.

Students' conceptual model of a good community attachment

BACKGROUND

In 1994, Manchester University Medical School introduced a new integrated curriculum using problem-based learning and which places an increased emphasis on community-based education.

AIMS

Students commonly use a particular label ("a good GP" (general practitioner)) to describe a positive experience in the community. The purpose of the study was to explore what students mean by "a good GP" and how this relates to their perceptions of the value of the community aspect of the course.

METHOD

Three single-year focus groups were run with year 3, 4 and 5 students. A model was then derived which was explored and checked against the views of a cross-year focus group.

RESULTS

A theoretical model based on student conceptualization of "a good GP" was developed. "A good GP" was found to consist of the GP as a teacher, as a role model and as an indicator of a positive learning environment. With regard to "good teacher", students felt that the GP's enthusiasm about teaching and involving the student in an active learning process was important. For "good role model", students emphasized communication skills and non-judgmental attitudes. With regard to "good learning environment", a friendly atmosphere, variety of activities, and flexibility shown by the staff of the health centre were important.

CONCLUSIONS

Students hold a complex conceptual model of "a good GP" which the label does not convey. We suggest that for evaluations of student experiences it is important to explore in depth what students mean by particular terms or labels.

Search for heavy particles decaying into electron-positron pairs in pp collisions

We present results of searches for technirho (rho(T)), techniomega (omega(T)), and Z' particles, using the decay channels rho(T),omega(T),Z'-->e(+)e(-). The search is based on 124.8 pb(-1) of data collected by the D0 detector at the Fermilab Tevatron during 1992-1996. In the absence of a signal, we set 95% C.L. upper limits on the cross sections for the processes pp-->rho(T),omega(T),Z'-->e(+)e(-) as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate rho(T) and omega(T) states with masses below about 200 GeV. We exclude a Z' with mass below 670 GeV, assuming that it has the same couplings to fermions as the Z boson.

Referrals and relationships: in-practice referrals meetings in a general practice

BACKGROUND

GP referrals to secondary care are an important factor in the cost of running the NHS. The known variation in referral rates between doctors has the potential to cause tension within primary care which will be exacerbated by the latest reorganization of primary care and the trend towards capitation-based budgets. The importance of postgraduate learning for GPs has been recognized; continuing professional development is moving towards self-directed practice-based learning programmes. Educational interventions have been shown to alter doctors' prescribing behaviour. This, together with the pressure on accounting for referral activity, makes the prospect of improving, and possibly reducing, referral activity through educational interventions very attractive.

OBJECTIVES

This study complemented a randomized controlled trial (RCT) which investigated whether an intervention of the type which had reduced prescribing costs would have a similar effect on referral activity.

METHODS

The context of the study, description of the characteristics of the practice and the issues seen as important by the doctors and practice manager were identified through preliminary semi-structured interviews. The practice then held a series of educational in-practice meetings to discuss referrals and issues arising from referrals. The audio- and videotaped transcripts were interpreted using content and group dynamic analysis. Participants commented upon our preliminary findings. In addition, we used dimensional analysis to induce a preliminary theory describing the effect of the intervention on this general practice which enabled us to review the findings of the parallel RCT. The educational value of the meetings and the learning needs of the participants were also assessed.

RESULTS

Our complementary study showed no alteration of practice referral rates following the educational intervention. The qualitative study, unencumbered by the assumptions inherent in the development of the hypothesis tested in the RCT, highlighted the complexity of decision making in general practice and the likely impact of historical background and a variety of internal and external pressures on this self-directive educational intervention. The practice members described the individual and group learning needs identified as a result of the meetings.

CONCLUSION

The findings of this study raise important questions for developing practice-based learning. The outcomes of self-directive interventions in practices will be influenced by internal and external events both past and present. Such outcomes may be qualitative and difficult to measure. They are likely to differ from outcomes seen when interventions are applied to groups of doctors who are not all members of the same practice.

Experimental studies on small intestinal pouch motility and evacuation

The aim of the study was to investigate pouch motility and evacuation under standardised conditions with a minimum of external influence.

METHODS

Ileal J-pouches had been constructed 30 cm proximal to the ileocecal valve in 10 dogs (6 pelvic/4 gastric configuration). After 8 weeks the following examinations were performed: (1) measurement of pouch compliance by balloon distension, (2) measurement of pouch contractions by strain gauge transducers, (3) radiological imaging of pouch contractions and evacuation, (4) evacuation scintigraphy and (5) radiological determination of small intestinal transit time.

RESULTS

Compliance (2.3 +/- 1.1 mmHg/ml) and small intestinal transit time (31.6 +/- 7.5 h) were significantly higher in the pouch group than in controls (0.5 +/- 0.2 mmHg/ml, 8.0 +/- 2.8 h; p < 0.05). Scintigraphy and radiography showed delayed pouch evacuation (t(1/2) = 109 +/- 52 min). Strain gauge measurements revealed irregular pouch contractions without detectable propagation. Contraction amplitudes (40.4 +/- 22.9 g) and frequencies (10.4 +/- 1.0/min) were equal all over the pouch. There were no functional differences between gastric and pelvic pouch configuration.

CONCLUSION

Small intestinal pouches act as reservoirs. Uncoordinated motility patterns contribute to this function. Other factors than pouch motility are responsible for evacuation.

Does loperamide affect motor activity after proctocolectomy and ileal pouch-anal anastomosis? An experimental study in dogs

This study investigated the effect of loperamide on the motor function of small intestine and J-pouch. Proctocolectomy and ileal pouch-anal anastomosis were performed in four dogs. Motility was recorded by serosal electrodes and strain gauge transducers. The intestinal transit time was determined radiologically. Multiple measurements were performed before and during chronic administration of loperamide. This treatment led to a significant decrease in median stool frequency from 11 (10-13) to 9 stools/day (8-12) and a tendential increase in intestinal transit time from 60 (50-105) to 70 min (60-90). This was not accompanied by significant changes in fasted or postprandial motility. There were no significant differences in the characteristics of the migrating myoelectric complex or in the fed pattern, either in the small intestine or in the pouch. Loperamide thus does not significantly affect intestinal motility after ileal pouch-anal anastomosis. The reduction in stool frequency seems to be due to antisecretory effects in the first line.

Quasi-model-independent search for new high p(T) physics at D0

We apply a quasi-model-independent strategy ("Sleuth") to search for new high p(T) physics in approximately 100 pb(-1) of pp collisions at square root of (s) = 1.8 TeV collected by the D0 experiment during 1992-1996 at the Fermilab Tevatron. We systematically analyze many exclusive final states and demonstrate sensitivity to a variety of models predicting new phenomena at the electroweak scale. No evidence of new high p(T) physics is observed.

Three top Canadian and personal health concerns of a random sample of Nova Scotian women

We sought to understand the subjective reports of women's health concerns. A randomly dialled telephone survey was conducted resulting in a sample of 458 women (Caucasian/European = 302, Native/Aboriginal = 81, Black = 75), aged 18-81. Women were asked in an open-ended format to list their three top health concerns for themselves and then for Canadian women. Responses were recorded verbatim and categorized into one of nine mutually exclusive health concern categories. The three main health concerns for Canadian women were: Psychosocial Issues, Other Specific Illnesses, and Cancer. The three most important personal health concerns were Psychosocial Issues, Other Specific Illnesses, and Heart and Related Diseases. Few ethnic differences were noted. Results suggest that it is important to recognize and attempt to alleviate health concerns about stress and depression, which are not usually considered as being major health problems by health care professionals.

Comparison of colonic J-pouch reconstruction and straight coloanal anastomosis after intersphincteric rectal resection

The tendency towards sphincter-preserving resection for distal rectal cancers has led to the technique of straight coloanal anastomosis (CAA) and colonic J-pouch anal anastomosis (CPA) after low anterior resection. The aim of the present study was to compare complication rate, anorectal physiology and functional results after both types of reconstruction after ultra-low intersphincteric resection. A total of 31 patients who had undergone CPA were followed up prospectively using anorectal manometry and a standardised questionnaire and were compared with 63 patients who had undergone CAA and were followed up in the same way. The complication rate after CPA did not differ significantly from that after CAA. One year postoperatively, the median stool frequency and urgency were reduced after CPA (1.7+/-2.2/day; 7% vs. 2.4+/-3.6/day; 14%; P<0.05). Three months after colostomy/ileostomy closure, the maximum tolerable volume, threshold volume and compliance were decreased after CAA when compared with CPA (55+/-12, 34+/-12, and 3.9+/-0.3 ml/mmHg vs. 85+/-21, 53+/-11 and 6.2 ml/mmHg, respectively; P<0.05). Anal manometry revealed no significant differences in the anal resting and squeeze pressure. One year postoperatively, continence also did not differ significantly between CPA and CAA. Colonic J-pouch reconstruction seems to be superior to the straight coloanal anastomosis, especially during the first postoperative year. In view of the often poor prognosis of the patients, it is the reconstruction of choice after ultra-low resections of the rectum.

Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV

The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Ratios of multijet Cross Sections in p p collisions at radical(s) = 1.8 TeV

We report on a study of the ratio of inclusive three-jet to inclusive two-jet production cross sections as a function of total transverse energy in p&pmacr; collisions at a center-of-mass energy sqrt[s] = 1.8 TeV, using data collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. The measurements are used to deduce preferred renormalization scales in perturbative O(alpha(3)(s)) QCD calculations in modeling soft-jet emission.

Inclusive jet production in pp(macro) collisions

We report a new measurement of the pseudorapidity (eta) and transverse-energy ( E(T)) dependence of the inclusive jet production cross section in pp(macro) collisions at square root of s = 1.8 TeV using 95 pb(-1) of data collected with the D0 detector at the Fermilab Tevatron. The differential cross section d(2)sigma/(dE(T)d eta) is presented up to eta = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.

Search for large extra dimensions in dielectron and diphoton production

We report a search for effects of large extra spatial dimensions in pp collisions at a center-of-mass energy of 1.8 TeV with the D0 detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% C.L. on the effective Planck scale between 1.0 and 1.4 TeV for several formalisms and numbers of extra dimensions.

Evidence-based Chirurgie des Rektumkarzinoms

The surgery of rectal cancer has seen significant development in recent years. When there is a multitude of therapeutic options available, it is essential to identify what can be considered a proven standard or, at least, what has to be included in planning a surgical treatment. Therefore, at this point of time a distal resection margin of 2 cm, total mesorectal excision, en-bloc resection of adherent structures, colonic pouch reconstruction after very deep resections and limitation of local excision to T1/G1 tumors have to be regarded as standards of the surgical strategy.

Three top Canadian and personal health concerns of a random sample of Nova Scotian women

We sought to understand the subjective reports of women's health concerns. A randomly dialled telephone survey was conducted resulting in a sample of 458 women (Caucasian/European = 302, Native/Aboriginal = 81, Black = 75), aged 18-81. Women were asked in an open-ended format to list their three top health concerns for themselves and then for Canadian women. Responses were recorded verbatim and categorized into one of nine mutually exclusive health concern categories. The three main health concerns for Canadian women were: Psychosocial Issues, Other Specific Illnesses, and Cancer. The three most important personal health concerns were Psychosocial Issues, Other Specific Illnesses, and Heart and Related Diseases. Few ethnic differences were noted. Results suggest that it is important to recognize and attempt to alleviate health concerns about stress and depression, which are not usually considered as being major health problems by health care professionals.

[Risk factors for anastomosis dehiscence after very deep colorectal and coloanal anastomosis]

INTRODUCTION

Very low colorectal anastomoses are considered to be more prone to complications than other anastomoses. We aimed to analyze possible risk factors for the surgically most relevant complication, anastomotic leakage.

METHODS

Uni- and multivariate analysis of the relation between leakage and 18 patient- and procedure-dependent variables were performed in 98 patients after very low colorectal or coloanal anastomosis.

RESULTS

In all, 18 patients developed a dehiscence. Two patients, both without a protective stoma, died because of the leakage (overall mortality 2%). From all analyzed variables, only smoking remained as an independent risk factor for anastomotic dehiscence. For all other parameters, such as protective stoma, experience of the surgeon, stage of tumor, radiation therapy, or the need for blood transfusions there was no significant correlation.

CONCLUSIONS

From our study, a typical risk pattern for anastomotic dehiscence, with the exception of being a smoker, cannot be defined. Presumably, anastomotic leakage is being caused by a multitude of factors, such as a preexisting or intra-/postoperatively developing reduction of microperfusion, which have a strong influence but cannot be as readily evaluated as other parameters. Until this situation improves, protective stomata, which do not prevent leakage but attenuate the consequences, should be used regularly.

Endoscopic ultrasonography in the preoperative staging of gastric cancer: accuracy and impact on surgical therapy

BACKGROUND

Endoscopic ultrasonography (EUS) is a standard procedure in the preoperative staging of patients with gastric carcinomas. Herein we present our experience with EUS and discuss the results and their implications for surgical therapy.

METHODS

A total of 116 patients with histologically confirmed gastric adenocarcinoma were referred to EUS and classified prospectively by the TNM system. The results of the preoperative endosonographic staging were compared with the definitive histopathological results after the operation.

RESULTS

The overall accuracy of EUS for determination of the T stage was 78%. The accuracy for the T1 and T2 stages was 80% and 63%, respectively. With 20% and 30%, there was a relatively high rate of overstaging in these cases. The accuracy for T3 and T4 tumors was 95% and 83%, respectively. The accuracy of EUS for determination of the N stage was 77%, with a sensitivity of 91% and a specificity of 84%. Resectability was predicted correctly with a sensitivity of 94% and a specificity of 83%.

CONCLUSIONS

Generally accepted standards for the therapy of advanced gastric carcinomas do not exist. In cases where the therapeutic strategy is surgical exploration, no preoperative staging is necessary. In cases with differentiated treatment strategies, the accuracy of EUS is not sufficient for the selection of patients for endoscopic resection. Its accuracy for submucosal cancer invasion and for the detection of lymph node metastases needs to be further enhanced. If only multimodal therapy is considered, EUS staging seems to be absolutely mandatory. Patients classified preoperatively as T1 to T3 can be operated on primarily with sufficient security. In patients where radical resection of the tumor seems doubtful, we recommend that a diagnostic laparoscopy be performed to confirm the diagnosis.

Effect of artificial valves on intestinal adaptation in the short-bowel syndrome: an integrated study of morphological and functional changes in rats

Two-third-resections of the proximal or distal small bowel with and without artificial valves were performed in rats. Intestinal adaptation led to a significant increase in bowel diameter, villus height and villus diameter and consequently in absorptive mucosal surface area per unit of serosal area. Additional artificial valve construction did not affect the calculated mucosal surface area after proximal resection, while it significantly decreased the absorptive area by the occurrence of large, plump villi after distal resection. There was no change in small-intestinal absorption of water, glucose and electrolytes per unit mucosa with valve construction. DNA cytometry showed that artificial valves led to mucosal hyperplasia without hypertrophy. These morphological changes coincided with a significant increase in basal and stimulated gastrin release. The body weight was unchanged or even worse in the valve groups than after resection alone, despite a significantly prolonged transit time. Therefore, in our study, artificial valves did not result in functional improvements after small intestinal resections.

[Surgical treatment of high anorectal and rectovaginal fistulas with the use of transanal endorectal advancement flaps]

INTRODUCTION

Sphincterotomy can be avoided in the repair of high anorectal or rectovaginal fistulas by use of rectal advancement flaps.

METHODS

Between 1986 and 1998, 22 patients with high anorectal and 15 patients with rectovaginal fistulas underwent fistulectomy without sphincterotomy and consecutive transanal rectal advancement flap repair.

RESULTS

Primary healing was achieved in 81% (30/37 patients). There was no disturbance of continence though anal resting pressures decreased postoperatively. Recurrences occurred in 4 of 12 patients with Crohn's disease (2 anorectal, 2 rectovaginal) and in 1 patient with traumatic anorectal fistula. There were no recurrences in patients with cryptoglandular disease, while the operation failed in 2 patients with ergotamine-induced fistulas.

CONCLUSIONS

This operative approach achieves a high primary healing rate with optimal functional outcome. Despite good results the indication should be set carefully in patients with Crohn's disease.

Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV

Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.

Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV

We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.

Myoelectric and motor activity after proctocolectomy and ileal pouch-anal anastomosis in dogs

BACKGROUND

The aim of this study was to investigate the motor function of the ileoanal pouch and to evaluate its coordination with proximal small-intestine motility.

METHODS

Proctocolectomy and ileal J pouch-anal anastomosis were performed in 12 dogs. Motility was recorded by serosal electrodes and strain gauge transducers.

RESULTS

Transmission of the migrating motor complex (MMC) on the pouch appeared in only 37 of 109 measurements. On the ascending limb there was a constant irregular activity with no MMC detectable. Motility pattern of the pouch did not change postprandially. Spontaneous defecation always appeared independently from MMC transmission without an increase of electrical or mechanical activity or endoluminal pouch pressure.

CONCLUSIONS

Ileal pouch motility is independent from motility patterns of the proximal intestine. Its random contractile activity might provide storage function and make the pouch act as a functional reservoir. Intrinsic pouch motility is not responsible for pouch evacuation under physiologic conditions.

Prediction accuracy and financial savings of four screening tests for a sequential test of clinical performance

BACKGROUND

Sequential testing of clinical performance is an effective strategy to reduce cost of testing.

PURPOSE

To evaluate prediction accuracy and financial savings of 4 screening tests of clinical performance.

METHODS

Screening tests were created from a 13-case examination taken by 434 medical students at 4 schools. Regression analysis determined prediction accuracy for 2 test outcomes. Financial savings were computed from published estimates.

RESULTS

Zero false passes were obtained with the "Total Number of Cases Passed" screening test, but it saved only 27%. Sixty-two percent savings with 5% false passes occurred with the "Classification" screening test. The "Scale" and "Mini Test" screening tests would have excused 79% and 67% examinees with 5% and 1% false passes, respectively.

CONCLUSIONS

Prediction accuracy varies with screening test and outcome measure. Sequential testing of clinical performance can save 40% to 60% with low false pass rates. However, programs need to consider loss of information for curriculum and individual feedback relative to financial savings.

Exploring biomolecular recognition using optical biosensors

Understanding the basic forces that determine molecular recognition helps to elucidate mechanisms of biological processes and facilitates discovery of innovative biotechnological methods and materials for therapeutics, diagnostics, and separation science. The ability to measure interaction properties of biological macromolecules quantitatively across a wide range of affinity, size, and purity is a growing need of studies aimed at characterizing biomolecular interactions and the structural elements that drive them. Optical biosensors have provided an increasingly impactful technology for such biomolecular interaction analyses. These biosensors record the binding and dissociation of macromolecules in real time by transducing the accumulation of mass of an analyte molecule at the sensor surface coated with ligand molecule into an optical signal. Interactions of analytes and ligands can be analyzed at a microscale and without the need to label either interactant. Sensors enable the detection of bimolecular interaction as well as multimolecular assembly. Most notably, the method is quantitative and kinetic, enabling determination of both steady-state and dynamic parameters of interaction. This article describes the basic methodology of optical biosensors and presents several examples of its use to investigate such biomolecular systems as cytokine growth factor-receptor recognition, coagulation factor assembly, and virus-cell docking.

[Colonic pouch]

The tendency towards sphincter-preserving resection for distal rectal cancers has led to a revival of the technique of coloanal anastomosis (CAA) in recent years. In order to improve functional results, creation of a colonic J-pouch in conjunction with a coloanal anastomosis (CPA) was proposed. Two different operation techniques exist: i) Double-stapling with the anastomosis close to the dentate line and ii) intersphincteric resection with the anastomosis located immediately at the dentate line. A long rectal remnant after double-stapling leads to urgency in 15% of the patients due to stool retention in the atonic remnant. No propulsive motility patterns were recorded from the pouch which is emptied passively by upper colonic peristalsis. Therefore colonic pouches should be fashioned of descending colon and should not exceed a length of 6 cm in order to prevent stool fragmentation. Under these conditions the average stool frequency is reduced from 2-6/d after CAA to 1-3/d after CPA. This effect is maximal during the first postoperative months, but is still significant after 3 years. Colonic pouch construction also leads, due to better blood supply and prevention of pelvic hematomas, to a significant decrease of the anastomotic insufficiency rate from 10.0% after CAA to 5.4% after CPA. Therefore creation of a colonic J-pouch should be combined with coloanal reconstruction if the oncologic situation allows a sphincter-preserving procedure.

Falls in elderly people: is the risk suitably assessed?

Results of the annual screening of people over the age of 75 years were used to determine whether the risk of falling in this age group is adequately assessed. The study group comprised primary healthcare professionals employed within six counties throughout England and Wales. Three per cent of respondents indicated that they use formal risk assessment tools when undertaking screening of people over 75 years. Analysis of the answers provided by these respondents, and of their assessment tools used, indicates that none of the tools are suitable for identifying those people at risk of falling within the home environment. Ninety-seven per cent of respondents indicated that they did not use a formal risk assessment tool for this age group. Analysis of the data provided by these respondents identified that the information gathered did suitably identify those people at risk of falling within the home.

[Ulcerative colitis--late functional results of ileoanal pouch anastomosis]

Stool frequency after ileal pouch-anal anastomosis (IPAA) is about 5/day after adaptation during the first year. It depends on stool volume and pouch capacity, not on the design of the pouch. In most cases evacuation is spontaneous and as complete as in healthy rectum. 67% of patients are perfectly continent, while 19% have to wear pads due to intermittent leakage. Complete incontinence is reported in 0-4% of the patients. Preservation of the anal transitional zone by the double-stapling technique does not improve functional results when compared to endoanal mucosectomy or intersphincteric resection. Impairment of continence is caused by damage of the internal sphincter with consecutive decrease of the pouch-anal pressure gradient. Despite altered reflex activity, stool discrimination is preserved in most patients. The loss of colonic water and electrolyte absorption is compensated by decreased renal excretion. Alterations in bile acid metabolism are lower after IPAA than after ileostomy. Bacterial overgrowth may lead to deterioration of the functional results.

Is the phonological loop responsible for intelligence-related differences in forward digit span?

Children with mild mental retardation were compared with CA-matched and verbal-age-matched children without mental retardation on a forward digit span task. Forward digit span is typically used as a measure of the phonological loop (Baddeley, 1986). We hypothesized that intelligence-related differences in forward digit span are largely due to central executive functioning rather than phonological loop functioning. Results showed that the highly significant group difference in forward digit span was reduced to nonsignificance when a measure of central executive functioning was covaried out.

[Direct ileum pouch-anal anastomosis in ulcerative colitis: function and complications after stapler technique]

Stapled ileal pouch-anal anastomosis after proctocolectomy enables a continence preserving reconstruction. We assessed complications and functional outcome after ileoanal pouch-anastomosis in 86 consecutive patients with ulcerative colitis. There was no postoperative mortality. 2 patients required permanent ileostomy and pouch excision for manifestation of unsuspected Crohn's disease. Major postoperative complications consisted of pelvic sepsis (n = 2), anastomotic leakage (n = 4), bleeding (n = 1), pancreatitis (n = 3) and peritonitis (n = 1). Both frequencies of bowel movements and degree of continence improved with time. Two years after take down of the deviation ileostomy frequency of bowel movements was 5,6 [2]/die. At this time no patient complained of major incontinence. Minor incontinence was reported with 9% and 14% during day-time and night-time respectively. It is concluded that direct stapled ileal pouch-anal anastomosis is a safe procedure with excellent functional results for patients with ulcerative colitis.

[Streptococcal toxic shock-like syndrome"--a rare complication of pyogenic skin infections]

In recent years there is an increasing incidence of streptococcal toxic shock-like syndrome in otherwise healthy adults. It is characterized by feaver, rash, hypotension and early shock with consecutive organ failure and a mortality rate of about 30%. Only early, aggressive and repeated surgical debridement can reduce the bacterial load and decrease circulating exotoxins and thereby in combination with antibiotic therapy decrease the high mortality of this entity.

[Preoperative staging of stomach carcinoma with endosonography--fact or fancy?]

From January 1993 till December 1995, a total of 116 consecutive patients with gastric carcinoma were evaluated with endosonography and the results were compared with the histology of the resected specimen. The accuracy rate of the endosonography was 80% for T1 tumors an 83% for T4 tumors, and the sensitivity and specificity in the detection of regional involved lymph nodes were 91% and 84% respectively. Therefore endosonographic staging alone ist not a valuable pretherapeutic procedure to decide about endoscopic therapy in limited and neoadjuvant chemotherapy in extended gastric carcinoma.

[Preoperative diagnosis of laparoscopic cholecystectomy. Is there an indication for routine intravenous cholangiography?]

In a retrospective study including 163 patients we investigated the necessity of i.v. cholangiography in preoperative routine diagnostic workup prior to laparoscopic cholecystectomy. We evaluated the evidence of i.v. cholangiography concerning the anatomy of the biliary system, the evidence of common bile duct or cystic duct stones and the influence on the further therapeutic procedure. While the common bile duct could be demonstrated in 96.3%, the cystic duct could be visualized in only 54.6%. One out of two patients with a short cystic duct was identified. Stones in the gallbladder were recognized in 72.4% of cases, while only two out of three patients with common bile duct stones were diagnosed. In nine cases a deep junction of the cystic duct was found, but there was no influence on further operative procedure. Thus we found no improvement after routine use of i.v. cholangiography concerning the evidence of common bile duct stones or avoidance of intraoperative lesions of the common bile duct. The routine use of i.v. cholangiography prior to laparoscopic cholecystectomy is therefore not justified.

[Value of intraluminal intestinal decompression by endoscopic placement of a Dennis tube in therapy of ileus. Retrospective clinical study of 174 patients]

For determination of the efficacy of intraluminal bowel decompression by an endoscopically placed Dennis tube, 174 patients with paralytic ileus or different kinds of partial small bowel obstruction were reviewed retrospectively. There were 66 cases (37.9%) of early postoperative ileus (A), 27 (15.5%) of late postoperative ileus (B), 38 (21.8%) of paralytic ileus (C), 31 (17.8%) with obstruction due to advanced intraabdominal tumors (D), and 12 (6.8%) of obstructive ileus caused by inflammatory stenosis of the small bowel in Crohn's disease (E). Successful endoscopic placement of the intestinal tube was achieved in 97.2% of patients. Placement of the tube was impossible in 5 cases. A total of 95 patients (54.6%) were successfully managed by long intestinal tube decompression. Success rates for the individual groups were 71.2% (A), 18.5% (B), 86.8% (C), 16.1% (D), and 41.7% (E). Some 75 patients (43.1%) had to be operated on because of insufficient conservative therapy. Four patients with advanced intraabdominal tumors died during the treatment with the intestinal tube; 13 patients died postoperatively. There was no tube-related mortality, but tube-related complications occurred in 6.9%. We conclude that intraluminal intestinal tube decompression after endoscopic placement provides a therapeutic tool with a concomitant low complication and high success rate in paralytic and early postoperative ileus.

Foundations for a healthy future

Health promotion activities with children and young people are important as they take messages about health seriously and can be influential in spreading messages about healthy living to their friends and families. Child health professionals have an important role to play in passing on messages of positive health to children and young people. Peer education is a useful way of passing on messages about health to young people. This article shares examples of three health promotion projects with children in a community trust, looking at asthma, sex education and testicular examination.

Endoscopic therapy of benign anastomotic strictures of the colorectum by electroincision and balloon dilatation

BACKGROUND AND STUDY AIMS

Endoscopic dilatation is the standard therapy for postoperative colorectal anastomotic strictures, although it carries the risk of perforation at the weakest part of the anastomosis. In order to minimize this risk we have developed a combined technique of endoscopic electroincision and hydraulic balloon dilatation.

PATIENTS AND METHODS

Thirty-six symptomatic patients with benign colorectal anastomotic strictures were referred for endoscopic electroincision with consecutive balloon dilatation, if the diameter of the anastomosis was less than 12 mm (n = 15) or if the diameter was less than 20 mm and the patient complained of repeated obstructive symptoms under conservative therapy (n = 21). Under direct endoscopic control the scar tissue at the anastomotic line was incised radially with the tip of the polypectomy snare or with a papillotome. Endoscopic hydraulic balloon dilatation was then performed, using a pressure of 35 PSI for three minutes. An endoscopic or radiological control was carried out on the second day, and balloon dilatation was repeated if necessary.

RESULTS

The combined technique of electroincision and consecutive balloon dilatation was performed successfully in 35 patients. In only one patient this therapy could not be performed, because of a long stenotic segment, and surgery was necessary. In 24 patients one single dilatation was sufficient after electroincision, whereas six patients required two, and five patients required three consecutive balloon dilatations. There were no severe complications such as bleeding or perforation. Complete follow-up evaluation was possible in 25 patients. In five cases recurrences appeared within the first year; all could be treated successfully by further balloon dilatation.

CONCLUSIONS

The combination of endoscopic electroincision and hydraulic balloon dilatation leads to a high long-term clinical success with a minimum of complications. Therefore, in our opinion it is a useful method in the treatment of benign colorectal anastomotic strictures.

[Endosonography control of percutaneous paracoccygeal drainage of deep pelvic abscesses after rectum resection]

Pelvic abscesses are severe complications after rectal surgery. In recent years, surgical drainage has been edged out by percutaneous drainage techniques. We report our experience with the drainage of postoperative pelvic abscesses via the paracoccygeal route controlled by endosonography. In eight patients the diagnosis of a retrorectal pelvic abscess was established by endosonography and confirmed by endosonographically controlled exploratory puncture. Drainage of the abscesses was performed via the paracoccygeal access route by trocar or Seldinger technique under permanent visual control by endoluminal sonography. Irrigation of the abscess cavity was than performed daily. In all cases drainage was successful without complications. Duration of drainage was 9-14 days with a mean of 10.8 days. In one patient there was a recurrence of the abscess because of early removal of the drainage catheter. Because of its overall availability and its good results, paracoccygeal percutaneous endosonographically controlled drainage seems to be a suitable uncomplicated method for drainage of postoperative pelvic abscesses.

Differences in intracellular CA2+ stores of submandibular cells of adult and newborn rats

The intracellular Ca2+ stores of submandibular acinar cells of adult and newborn rats were compared by measuring changes in cytosolic Ca2+ ([Ca2+]i) with the Ca2+-sensitive fluorescent probe, fura-2, in intact cells and 45Ca2+ release in permeabilized cells. In cells of adult rats, acetylcholine (ACh) and thapsigargin (TG) elicited, respectively, a 105% and 125% net increase in [Ca2+]i in Ca2+-free medium. In cells of newborn animals, the ACh-induced [Ca2+]i increase (218%) was larger; but the TG-induced increase was significantly smaller (77%), suggesting that the TG-sensitive Ca2+ pump of the store is less developed, abundant, or responsive in these cells. After ACh or TG, ionomycin elicited a further Ca2+ release. Ionomycin by itself completely discharged the ACh- and TG-sensitive store in cells of mature glands but not in cells of immature glands, suggesting a further difference in the distribution of the agonist and ionomycin sensitivities in the two types of cells. After exposure to ACh + ionomycin or TG + ionomycin, collapsing the intracellular pH gradient with monensin caused a third and large Ca2+ release (262% and 289%, respectively) in cells of adult rats, but a significantly smaller release (96%, P < 0.001, and 57%, P < 0.001, respectively) in cells of newborn rats, suggesting that a third, IP3-insensitive acidic store is significantly smaller in cells of immature glands. In permeabilized and 45Ca2+-loaded cells, inositol-1,4,5-trisphosphate (IP3, 5 microM) induced an identical 45Ca2+ release (34% and 33%, respectively) in both types of cells, but TG induced a significant smaller 45Ca2+ release in cells of immature glands (15%) than in cells of mature glands (33%). Monensin discharged <10% of loaded 45Ca2+ in both types of cells, indicating that the radiotracer was not loaded into the monensin-sensitive store. These results suggest that in cells of immature glands: (1) the TG-sensitive Ca2+ pump of the IP3-sensitive store is not well developed; (ii) the IP3-sensitive store is not completely discharged by ionomycin; and (iii) an acidic store likely to be associated with secretory granules is also underdeveloped and of a smaller size than in cells of mature glands.

Small intestinal myoelectrical activity and bacterial flora after Roux-en-Y reconstruction

Small bowel myoelectrical activity and intestinal microflora were examined after partial gastrectomy and Roux-en-Y reconstruction in six dogs. Bacteriological analysis revealed a predominance of faecal bacteria. The basal electrical rhythm of the Roux limb was significantly decreased, while the frequency of phase III was increased (P < 0.05). In the bypassed duodenum, activity fronts occurred in only 25 per cent of experiments. Food intake led to an increase in the mean(s.e.m.) motility index in the Roux limb (from 46.1(9.4) to 75.0(21.5), P < 0.05), but not in the bypassed intestine (from 27.0(3.6) to 27.8(4.1), P not significant). Stimulation of the hypomotile bypassed intestine with cisapride induced an increase in the motility index from 27.0(3.6) to 111.2(16.5) (P < 0.001).