A111 CLINICAL AND PATHOLOGICAL OUTCOMES BETWEEN WATER EXCHANGE AND AIR INSUFFLATION USING NON-SEDATED EXTENDED FLEXIBLE SIGMOIDOSCOPY FOR AVERAGE RISK COLORECTAL CANCER SCREENING: PRELIMINARY FINDINGS FROM A RANDOMIZED CONTROL TRIAL

Background

Colorectal cancer (CRC) is Canada's third most common cancer type and represents approximately 11% of all cancer deaths. While sedated colonoscopy or flexible sigmoidoscopy (FS) continues to be considered for CRC screening, these modalities have limitations and risks. Another unevaluated screening modality, known as an extended FS (EFS), attempts to capitalize on the benefits of a FS while minimizing the risks involved with a sedated colonoscopy. EFS provides a scope-based examination up to the splenic flexure and then attempts to examine beyond, often to the point of the caecum. Providing the option for EFS may produce improvements in the patient experience and performance, which may improve the feasibility of using scope-based screening more broadly in screening programs.

Purpose

To determine the extent non-sedated EFS using the water exchange method (WE) is associated with a complete colon examination compared to the traditional air insufflation (AI) method using CO2 in an average-risk screening population.

Method

This randomized control trial included 90 non-sedated participants, screened by trained general surgery and gastroenterology clinicians at Kelowna General Hospital, British Columbia, Canada, using two different scope insufflation techniques, WE and AI. The primary outcome of interest was the cecal intubation rates (CIR), while secondary outcomes included the adenoma detection rate (ADR) and reported pain scores. Other metrics, such as patient satisfaction rates, sessile serrated adenoma detection rates (SSADR), and serrated lesion detection rates (SLDR) were also recorded.

Result(s)

The demographic characteristics between the WE and AI groups were statistically similar, with the mean age of participants being 58 and 57, respectively. During the study period, four endoscopists performed the EFS. There were higher initial satisfaction rates in the WE group vs the AI (95% vs 77%, satisfaction of ≥ 9/10 p = 0.028). CIR and ADR were similar between the WE and AI group (CIR = 93% vs 91%, p = 0.710), (ADR = 40% vs 34%, p = 0.660). The SSADR and SLDR were also similar between the WE and AI group (SSADR = 21% vs 14%, p = 0.408), (SLDR = 42% vs 36%, p = 0.528).

Conclusion(s)

EFS without sedation using either technique exceeds quality benchmarks recommended for sedated screening colonoscopy while maintaining adequate patient safety and comfort. The WE method optimizes a patient's overall experience making a strategy of average risk colorectal cancer screening with non-sedated WE EFS feasible.

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Kelowna General Hospital, Interior Health

Disclosure of Interest

None Declared

Sex dimorphisms in coagulation characteristics in the pediatric trauma population appear after puberty

BACKGROUND

The role of age and sex in mediating coagulation characteristics in injured children is not well defined. We hypothesize that thromboelastography (TEG) profiles are equivalent across sex in younger children and diverge after puberty.

METHODS

Consecutive trauma patients younger than 18 years were identified from a university-affiliated, Level I, pediatric trauma center (2016-2020) database. Demographics, injury characteristics, and TEG parameters were recorded. Children were categorized by sex and age (younger, ≤10 years; older, ≥11 years). Baseline characteristics, outcomes, and TEG parameters were compared using nonparametric tests as appropriate. To account for the effects of confounding variables, analysis of covariance was performed controlling for Injury Severity Score (ISS), admission Glasgow Coma Scale score, and pediatric age-adjusted shock index.

RESULTS

Six hundred forty-seven subjects were identified (70.2% male, median ISS, 10; interquartile range, 5-24; blunt mechanism, 75.4%). Among 395 younger children (≤10 years), there were no differences in TEG characteristics between sexes. Among 252 adolescents (≥11 years), males had greater kinetic times (1.8 vs. 1.4 min; p < 0.001), decreased alpha angles (69.6° vs73.7°; p < 0.001), and lower maximum amplitudes (59.4 vs. 61.5 mm; p = 0.01). Fibrinolysis was significantly lower in older females compared with younger females (0.4% vs. 1.5%, p < 0.001) and age-matched males (0.4% vs. 1.0%, p = 0.02). Compared with younger male children, adolescent males had greater kinetic times (1.8 vs. 1.4 min; p < 0.001), decreased alpha angles (73.5° vs. 69.6°, p < 0.001), lower maximum amplitudes (59.4 vs. 62 mm, p < 0.001), and less fibrinolysis (1.0% vs. 1.3%, p = 0.03). This interaction persisted after controlling for ISS, Glasgow Coma Scale, and pediatric age-adjusted shock index.

CONCLUSION

Sex dimorphisms in TEG coagulation profiles appear after puberty. This divergence appears to be driven by a shift in male coagulation profiles to a relatively hypocoagulable state and female coagulation profiles to a relatively hypercoagulable state after puberty.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic, Level III.

A95 OUTCOMES OF ERCP UNDER CONSCIOUS SEDATION COMPARED TO GENERAL ANESTHESIA: A PRE-POST RETROSPECTIVE COHORT REVIEW

Background

Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic and therapeutic procedure used to address pathologies of the pancreatic and biliary systems. ERCP performed under conscious sedation (CS) is the current standard of care but is limited by patient movement and agitation, especially in the context of lengthy or technically complex cases. Recent literature suggests that general anesthesia (GA) may optimize patient comfort and safety while reducing complications such as pancreatitis, perforation, and mortality. In October 2017, Kelowna General Hospital (KGH) transitioned the standard anesthesia modality for ERCP from CS to GA.

Aims

To investigate differences in complications and patient outcomes for ERCP performed under CS (n=1334) before the practice change compared to GA (n=899) after the practice change.

Methods

Our study is a pre-post retrospective chart review of 2,233 patients who underwent ERCP between 2015 and 2020 at KGH. Demographic, clinical, procedural and outcome data were extracted from patient charts, and the data in CS and GA groups were compared using univariate statistical analysis.

Results

Preliminary results show rates of post-ERCP pancreatitis (6% vs. 4%; p=0.018) and rates of procedure failure (8% vs. 3%; p&lt;0.001) were statistically significant and higher under CS before the practice change compared to under GA afterwards, respectively. The 30-day mortality rates, ICU transfer rates, return rates post-discharge, and rates of cholangitis were similar.

Our study showed improvements in several patient safety outcomes, including lower procedure failure rates and lower post-ERCP pancreatitis rates with ERCP performed under GA compared to CS.

Conclusions

Performing ERCP under GA rather than under CS is a valuable practice change that should be considered by ERCP-related programs across all health authorities due to its potential to optimize both patient comfort and safety significantly. The reduction in complication rates may have implications for net cost savings in the long term.

Funding Agencies

Kelowna General Hospital Foundation, Interior Health

DNA attenuates enterocyte Toll-like receptor 4-mediated intestinal mucosal injury after remote trauma

Intestinal mucosal injury occurs after remote trauma although the mechanisms that sense remote injury and lead to intestinal epithelial disruption remain incompletely understood. We now hypothesize that Toll-like receptor 4 (TLR4) signaling on enterocytes after remote injury, potentially through the endogenous TLR4 ligand high-mobility group box-1 (HMGB1), could lead to intestinal dysfunction and bacterial translocation and that activation of TLR9 with DNA could reverse these effects. In support of this hypothesis, exposure of TLR4-expressing mice to bilateral femur fracture and systemic hypotension resulted in increased TLR4 expression and signaling and disruption of the ileal mucosa, leading to bacterial translocation, which was not observed in TLR4-mutant mice. TLR4 signaling in enterocytes, not immune cells, was required for this effect, as adenoviral-mediated inhibition of TLR4 in enterocytes prevented these findings. In seeking to identify the endogenous TLR4 ligands involved, the expression of HMGB1 was increased in the intestinal mucosa after injury in wild-type, but not TLR4-mutant, mice, and administration of anti-HMGB1 antibodies reduced both intestinal mucosal TLR4 signaling and bacterial translocation after remote trauma. Strikingly, mucosal injury was significantly increased in TLR9-mutant mice, whereas administration of exogenous DNA reduced the extent of TLR4-mediated enterocyte apoptosis, restored mucosal healing, and maintained the histological integrity of the intestinal barrier after remote injury. Taken together, these findings identify a novel link between remote injury and enterocyte TLR4 signaling leading to barrier injury, potentially through HMGB1 as a ligand, and demonstrate the reversal of these adverse effects through activation of TLR9.

New insights into the pathogenesis and treatment of necrotizing enterocolitis: Toll-like receptors and beyond

Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in the preterm infant. The dismal results of current treatment for NEC highlight the urgent need for greater understanding of the pathogenesis of this disease, and the importance of discovering novel, molecular-specific therapies for it. Current dogma indicates that NEC development reflects an abnormal response by the premature infant to the microbial flora that colonizes the gastrointestinal tract, although the mechanisms that mediate these abnormal bacterial-enterocyte interactions and the reasons for the particularly increased susceptibility of the premature infant to the development of NEC remain incompletely explained. Recent evidence has shed light on an emerging role for the Toll-like receptors (TLRs) of the innate immune system as central players in the pathways that signal in response to enteric bacteria resulting in the development of NEC. We now review recent advances in the field of NEC and identify several exciting potential avenues for novel treatments by focusing on abnormal TLR4 signaling in the premature intestine in the pathogenesis of NEC. In so doing, we seek to offer new hope to the patients and their families who are affected by this devastating disorder.

Application of the singular perturbation method to reaction kinetics

The purpose of this paper is to show how to apply the singular perturbation method to the rate equations in reaction kinetics that involve different time scales. The Lindemann scheme has been chosen for illustration, and the steady-state and equilibrium approximations used in the Lindemann scheme are discussed.

Stochastic Model of Unimolecular Reactions and the RRKM Theory

A stochastic model of unimolecular reactions has been adopted for investigation of the validity and limitation of the RRKM theory. The error caused by the steady-state approximation for distribution of energized molecules is small, while the assumption of the internal energy equilibration of energized molecules might cause serious errors for reactions of low activation energies.

Extracellular high mobility group box-1 (HMGB1) inhibits enterocyte migration via activation of Toll-like receptor-4 and increased cell-matrix adhesiveness

Toll-like receptor-4 (TLR4) is the receptor for bacterial lipopolysaccharide, yet it may also respond to a variety of endogenous molecules. Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in newborn infants and is characterized by intestinal mucosal destruction and impaired enterocyte migration due to increased TLR4 signaling on enterocytes. The endogenous ligands for TLR4 that lead to impaired enterocyte migration remain unknown. High mobility group box-1 (HMGB1) is a DNA-binding protein that is released from injured cells during inflammation. We thus hypothesize that extracellular HMGB1 inhibits enterocyte migration via activation of TLR4 and sought to define the pathways involved. We now demonstrate that murine and human NEC are associated with increased intestinal HMGB1 expression, that serum HMGB1 is increased in murine NEC, and that HMGB1 inhibits enterocyte migration in vitro and in vivo in a TLR4-dependent manner. This finding was unique to enterocytes as HMGB1 enhanced migration of inflammatory cells in vitro and in vivo. In seeking to understand the mechanisms involved, TLR4-dependent HMGB1 signaling increased RhoA activation in enterocytes, increased phosphorylation of focal adhesion kinase, and increased phosphorylation of cofilin, resulting in increased stress fibers and focal adhesions. Using single cell force traction microscopy, the net effect of HMGB1 signaling was a TLR4-dependent increase in cell force adhesion, accounting for the impaired enterocyte migration. These findings demonstrate a novel pathway by which TLR4 activation by HMGB1 delays mucosal repair and suggest a novel potential therapeutic target in the amelioration of intestinal inflammatory diseases like NEC.

A role for connexin43 in macrophage phagocytosis and host survival after bacterial peritoneal infection

The pathways that lead to the internalization of pathogens via phagocytosis remain incompletely understood. We now demonstrate a previously unrecognized role for the gap junction protein connexin43 (Cx43) in the regulation of phagocytosis by macrophages and in the host response to bacterial infection of the peritoneal cavity. Primary and cultured macrophages were found to express Cx43, which localized to the phagosome upon the internalization of IgG-opsonized particles. The inhibition of Cx43 using small interfering RNA or by obtaining macrophages from Cx43 heterozygous or knockout mice resulted in significantly impaired phagocytosis, while transfection of Cx43 into Fc-receptor expressing HeLa cells, which do not express endogenous Cx43, conferred the ability of these cells to undergo phagocytosis. Infection of macrophages with adenoviruses expressing wild-type Cx43 restored phagocytic ability in macrophages from Cx43 heterozygous or deficient mice, while infection with viruses that expressed mutant Cx43 had no effect. In understanding the mechanisms involved, Cx43 was required for RhoA-dependent actin cup formation under adherent particles, and transfection with constitutively active RhoA restored a phagocytic phenotype after Cx43 inactivation. Remarkably, mortality was significantly increased in a mouse model of bacterial peritonitis after Cx43 inhibition and in Cx43 heterozygous mice compared with untreated and wild-type counterparts. These findings reveal a novel role for Cx43 in the regulation of phagocytosis and rearrangement of the F-actin cytoskeleton, and they implicate Cx43 in the regulation of the host response to microbial infection.

The development of animal models for the study of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of death and long-term disability from gastrointestinal disease in preterm infants, and is characterized by acute and chronic intestinal inflammation that may lead to systemic sepsis and multi-system organ failure. NEC typically develops in the preterm infant after the administration of tube feeds, although it may occasionally be seen in full-term babies. Despite extensive clinical experience in the management of patients with NEC, the underlying cellular and molecular mechanisms leading to its development remain incompletely understood. Several animal models have therefore been developed in a variety of species in order to study the pathogenesis of NEC and to develop more effective treatment strategies. This review seeks to examine the pros and cons of animal models that have been developed in the study of NEC over the past 30 years. It will highlight the various strengths and weaknesses of experimental approaches that have been used, and discuss potential directions for the development of such models for the future.

Interferon-gamma inhibits enterocyte migration by reversibly displacing connexin43 from lipid rafts

Necrotizing enterocolitis (NEC) is associated with the release of interferon-gamma (IFN) by enterocytes and delayed intestinal restitution. Our laboratory has recently demonstrated that IFN inhibits enterocyte migration by impairing enterocyte gap junctions, intercellular channels that are composed of connexin43 (Cx43) monomers and that are required for enterocyte migration to occur. The mechanisms by which IFN inhibits gap junctions are incompletely understood. Lipid rafts are cholesterol-sphingolipid-rich microdomains of the plasma membrane that play a central role in the trafficking and signaling of various proteins. We now hypothesize that Cx43 is present on enterocyte lipid rafts and that IFN inhibits enterocyte migration by displacing Cx43 from lipid rafts in enterocytes. We now confirm our previous observations that intestinal restitution is impaired in NEC and demonstrate that Cx43 is present on lipid rafts in IEC-6 enterocytes. We show that lipid rafts are required for enterocyte migration, that IFN displaces Cx43 from lipid rafts, and that the phorbol ester phorbol 12-myristate 13-acetate (PMA) restores Cx43 to lipid rafts after treatment with IFN in a protein kinase C-dependent manner. IFN also reversibly decreased the phosphorylation of Cx43 on lipid rafts, which was restored by PMA. Strikingly, restoration of Cx43 to lipid rafts by PMA or by transfection of enterocytes with adenoviruses expressing wild-type Cx43 but not mutant Cx43 is associated with the restoration of enterocyte migration after IFN treatment. Taken together, these findings suggest an important role for lipid raft-Cx43 interactions in the regulation of enterocyte migration during exposure to IFN, such as NEC.

Mandibular elongation by automatic distraction osteogenesis: the first application in humans

We report the case of a 65-year-old man who was the first person to have the right ramus of his mandible lengthened by 20mm by automatic continuous distraction osteogenesis. The device consists of two units: a component that is implanted into the bone, and an external component that is distant from the surgical site and mounted on a battery-driven portable syringe driver or infusion pump. A non-compressible drive cable connects the two.

Primary vs delayed surgery for spontaneous pneumothorax in children: which is better?

BACKGROUND

Controversy exists regarding the timing of surgery for spontaneous pneumothorax (SP), which can be performed either after the first development of pneumothorax or after a recurrent spontaneous pneumothorax has occurred. Treatment after recurrence is often adopted because of the purported low recurrence of SP treated nonoperatively and the historical morbidity of open surgery. However, the effectiveness of VATS (to video-assisted bullectomy and pleurodesis) has raised the possibility of performing primary VATS (PV) in all patients. The authors therefore hypothesized that PV is safe and effective for SP and sought to perform a cost-benefit analysis of PV vs secondary VATS (SV).

METHODS

After institutional review board approval, consecutive patients with SP (1991-2003) and no comorbidities were retrospectively divided into PV vs SV. Demographics, recurrent pneumothorax after VATS, length of stay, and costs were compared by Student's t test/chi2. The predicted incremental cost of PV was (cost of PV) - [cost of nonoperative treatment x (1 - recurrence rate)] + cost of SV x recurrence rate. Data are means +/- SEM.

RESULTS

There were 54 spontaneous pneumothoraces in 43 patients (11 bilateral), of whom 3 were excluded because of open thoracotomy. Of 51 pneumothoraces, nonoperative treatment was attempted in 37, of whom 20 recurred and thus required SV. Primary VATS was performed in 14. Both groups had similar age, sex, weight, height, admission heart rate, and room air oxygen saturation. Total treatment length of stay was significantly shorter for PV vs SV (7.1 +/- 0.96 vs 10.5 +/- 1.2, P = .04). However, morbidity from recurrent pneumothorax after VATS occurred more frequently after PV than SV (4/14 vs 0/20 P < .05). Based on the observed recurrence rate of 54%, performing PV on all patients with SP would increase cost by $4010 per patient and require a recurrence rate of 72% or more to financially justify this approach.

CONCLUSIONS

Contrary to the hypothesis, the increased morbidity and cost do not justify a strategy of PV blebectomy/pleurodesis in children with SP. Instead, secondary treatment is recommended.

Outcome after implantation of a novel prosthetic anal sphincter in humans

Background

A novel prosthetic anal sphincter (PAS) has been developed that aims to occlude by flattening and angulating the bowel, reproducing the action of the puborectalis muscle. The safety of the PAS has been confirmed in biomechanical, in vitro and long-term animal survival studies. The Medical Devices Agency approved implantation in 12 patients.

Methods

The PAS was placed in the pelvis around the anorectal junction via a transabdominal approach in 12 patients with severe faecal incontinence. The device was activated 6 weeks after surgery. Fibreoptic examination of the mucosa below the device was undertaken at various intervals during review.

Results

At a median follow-up of 59 (range 30–72) months nine of the 12 patients had a functioning PAS. There were no device-related infective complications after the initial operation but one patient developed pseudomembranous colitis and had the device removed. The PAS was effective in restoring continence in ten of 11 patients. Median (range) Cleveland Clinic continence scores improved from 16 (7–20) before to 3 (0–7) after surgery. In two patients the PAS was eventually removed owing to infection after revisional surgery. There was no clinical or histological evidence of gastrointestinal mucosal ischaemia.

Conclusion

The PAS was effective in restoring continence. There was no device-related infection after the initial operation, no device erosion and no clinical or histological evidence of gastrointestinal ischaemia.

The use of stable isotopes to evaluate water mixing and water use by flood plain trees along the Garonne valley

Before the confluence of the Tarn, the Garonne valley was the driest area in the entire south-west of France, due to the relatively low rainfall and low summer discharge of the Garonne River and its tributaries. The natural abundance of the stable isotope of oxygen (18O) and ionic charge of surface and ground water were used to estimate the water source for the Garonne River and phreatic subsurface water. We also measured these constituents in the sap of trees at several flood plain sites to better understand the source of water used by these trees. 18O signatures and conductivity in the Garonne River indicated that the predominance of water was from high altitude surface runoff from the Pyrenees Mountains. Tributary inputs had little effect on isotopic identity, but had a small effect on the conductivity. The isotopic signature and ionic conductivity of river water (delta18O: -9.1 per thousand to -9.0 per thousand, conductivity: 217-410 microS/cm) was distinctly different from groundwater (delta18O: -7.1 per thousand to -6.6 per thousand, conductivity: 600-900 microS/cm). Isotopic signatures from the sap of trees on the flood plain showed that the water source was shallow subsurface water (<30 cm), whereas trees further from the river relied on deeper ground water (>1 m). Trees at both locations maintained sap with ionic charges much greater (2.3-3.7x) than that of source water. The combined use of 18O signatures and ionic conductivity appears to be a potent tool to determine water sources on geographic scales, and source and use patterns by trees at the local forest scale. These analyses also show promise for better understanding of the effects of anthropogenic land-use and water-use changes on flood plain forest dynamics.

A new device for microincremental automatic distraction osteogenesis

We have invented a distraction device that can be placed intraorally and provides autodistraction. The device consists of two units: an implantable component that is applied directly on the bone, and an external component that is distant from the surgical site. The external component is mounted on a standard, battery-driven portable syringe driver or infusion pump. A fine flexible non-compressible tube connects the two. The compression of the bellows in the external component causes fluid to be forced through the connecting tube into the distraction component. The combination of the sealed system and incompressible fluid guarantees expansion of the bellows of the distraction component and gradually separates the bone segments.

Segmental mandibular reconstruction by microincremental automatic distraction osteogenesis: an animal study

We investigated the reconstruction of a surgically created critical size mandibular defect in sheep using a newly developed automatic distraction device. The device has an implantable component, which is fixed to the mandible to allow the transfer of the transport disc across the created defect, and an external component which is mounted on the activation pump and secured away from the site of bone distraction. Compression of the bellows in the external component causes fluid to be forced through the connecting tube into the distraction component. Distraction at a rate of 1 mm over 24 h was achieved in six sheep. New bone generated at the site of the created defects both anterior (compression side) and posterior (tension side) to the transport disc and had similar radiodensity to the adjacent mandibular bone eight weeks after the completion of distraction.

Smoking cessation. Pulling out the stops

The launch of smoking-cessation drug Zyban in June last year greatly increased demand on a local smoking-cessation service. It is important to use local media to increase awareness of local services. Health authorities and pharmaceutical companies should work with the media when new drugs may put extra strain on local services.

Attribution of responsibility for injury and long-term outcome of patients with paralytic spinal cord trauma

STUDY DESIGN

Survey.

OBJECTIVE

To assess the association between patients' perceptions of responsibility for the injury and long term outcomes.

SETTING

Duke University Medical Center Spinal Injury Service.

METHODS

One hundred and forty patients, who suffered spinal cord injuries between 1985 and 1990, were selected to participate in the study, and 26 (19%), including eight with quadriplegia, completed a telephone interview. The mean age at interview was 39+/-12 years and 12% were women. The mean time from injury to completion of the study was 8.7+/-1.5 years. Attribution of cause of injury, the Craig Handicap Assessment Reporting Technique, and the SF36 mental health depression/vitality surveyed instruments attribution of responsibility for the injury, functional capacity, mental health depression, and vitality.

RESULTS

The majority (18/26) of patients either totally blamed themselves or others for their injuries. Overall, there was no statistically significant association between attribution of injury and long-term outcomes. Outcomes were similar in patients who either totally blamed themselves or others for their predicament.

CONCLUSION

In this study, long-term outcomes were not influenced by whether patients perceived themselves as being responsible for their injuries.

Use of retinal biopsy to diagnose Bartonella (formerly Rochalimaea) henselae retinitis in an HIV-infected patient

A patient with the acquired immunodeficiency syndrome developed bilateral retinitis due to a Bartonella (formerly Rochalimaea) henselae infection. A retinal biopsy was performed when severe and progressive retinal infection failed to respond to empirical treatment for cytomegalovirus and Toxoplasma gondii. The biopsy specimen was stained with routine histopathological stains and the Steiner silver stain. Ribosomal DNA was extracted from formalinfixed, paraffin-embedded retinal tissue and amplified with the polymerase chain reaction assay, using Bartonella-specific primers. The amplified DNA fragment was cloned and sequenced. Staining with hematoxylin-eosin revealed tufts of proliferating vascular endothelium with numerous fusiformappearing cells, consistent with a diagnosis of bacillary angiomatosis. A Steiner silver stain revealed numerous small bacilli in the biopsy specimen. Amplification of DNA extracted from the tissue produced a fragment of 16S ribosomal DNA of the expected size; sequencing of the DNA fragment revealed that the infection was caused by B henselae. The retinal infection was treated with minocycline, doxycycline, and ciprofloxacin with improvement in visual acuity in the ensuing 12 weeks. To our knowledge, this is the first human immunodeficiency virus-infected patient with retinitis due to B henselae who was diagnosed by the identification of silver-staining bacilli and amplification and sequencing of B henselae with a polymerase chain reaction assay using a biopsy specimen of retinal tissue. Retinal biopsy is indicated, despite its potential for serious complications, in patients with acquired immunodeficiency syndrome who have a progressive, sight-threatening retinitis that is undiagnosed and unresponsive to therapy.

Seasonal changes in the Plasmodium falciparum population in individuals and their relationship to clinical malaria: a longitudinal study in a Sudanese village

Residents of Daraweesh village in Sudan were monitored for Plasmodium falciparum infection and malaria morbidity in 3 malaria seasons from 1993 to 1996. Malaria parasites were detected microscopically and by polymerase chain reaction (PCR) in a series of cross-sectional surveys. PCR revealed submicroscopical infections during the dry season, particularly among individuals who had recovered from a malaria episode following successful drug treatment. Clinical and subclinical infections were contrasted by assaying for allelic polymorphism at 2 gene loci, MSP-1 and GLURP and 2 hypotheses examined with reference to these data: that clinical malaria is associated with infection with novel parasite genotypes not previously detected in that host, or alternatively, that clinical malaria episodes are associated with an increased number of clones in an infection. We detected more mixed infections among clinical isolates, but people carrying parasites during the dry season were not found to have an increased risk of disease in the following malaria season. There was a clear association of disease with the appearance of novel parasite genotypes.

Leukemia cutis with prominent giant cell reaction

We present a case of leukemia cutis associated with a prominent giant cell component. This lesion was initially diagnosed as chronic granulomatous inflammation 1 year before the definitive diagnosis of leukemia cutis was made. Skin biopsy specimens showed numerous Langhans-type giant cells occurring singly and as poorly formed granulomas. However, the majority of the infiltrate consisted of immature myeloid cells, positive for chloroacetate esterase, lysozyme, and CD 68. Subsequent peripheral blood and bone marrow examinations confirmed the progression of the disease to acute myeloid leukemia.

Protective immune responses to Theileria annulata of relevance to vaccine development

A series of projects on Theileria annulata funded by the European Union (STD1/STD2/STD3) have provided convincing evidence that macrophage and natural killer (NK) cell-dependent immune mechanisms may directly control the proliferation of different stages of T. annulata in cattle. The evidence for this conclusion and the implications for vaccine development are discussed in the following paper.

The effect of intravenous administration of a chimeric anti-IgE antibody on serum IgE levels in atopic subjects: efficacy, safety, and pharmacokinetics

CGP 51901 is a non-anaphylactogenic mouse/human chimeric anti-human IgE antibody that binds to free IgE and surface IgE of IgE-expressing B cells but not to IgE bound to high affinity IgE receptors (Fc epsilonR1) on mast cells and basophils or low affinity IgE receptors (Fc epsilonR2) on other cells. A phase 1 double-blind, placebo-controlled, single dose study with doses of 3, 10, 30, and 100 mg of CGP 51901 was conducted in 33 pollen-sensitive subjects who had raised levels of serum IgE and received either intravenous CGP 51901 or placebo. The administration of CGP 51901 was well tolerated and resulted in a decrease of serum free IgE levels in a dose-dependent manner, with suppression after 100 mg of CGP 51901 reaching > 96%. Time of recovery to 50% of baseline IgE correlated with the dose of administered antibody and ranged from a mean of 1.3 d for the 3 mg to 39 d for the 100 mg dose. Total IgE, comprised of free and complexed IgE, increased as stored and newly synthesized IgE bound to CGP 51901. Complexed IgE was eliminated at a rate comparable with the terminal half-life of free CGP 51901 (11-13 d at all doses). Only one subject showed a weak antibody response against CGP 51901. We conclude that the use of anti-human IgE antibody is safe and effective in reducing serum IgE levels in atopic individuals and provides a potential therapeutic approach to the treatment of atopic diseases.

Marked bone marrow eosinophilia at the time of relapse of acute myeloblastic leukaemia in association with the appearance of translocation t(12;20)(q24;q11)

We report a case of acute myeloblastic leukaemia (AML), FAB type M2, with karyotype t(8;21)(q22;q22), who at the time of relapse showed marked eosinophilia of the bone marrow. Karyotype analysis showed the appearance of an additional clone t(8;21)(q22;q22),t(12;20)(q24;q11). To the best of our knowledge, marked eosinophilia has not been reported in association with this particular chromosomal translocation.

Possible mechanisms for the protective action of alpha-tocopherol in vascular hypoxia

1. The mechanism of the protective action of alpha-tocopherol (vitamin E) in sustaining noradrenaline-induced responses in vascular hypoxia was investigated using pharmacological methods. 2. Four vascular spasmogenic agents, methoxamine, acetylcholine, histamine and potassium, each with a different mode of action were used to produce responses in guinea-pig isolated portal vein. In each case the responses were significantly reduced by hypoxia or hypoxia and a substrate-free environment. 3. Pre-incubation of the vein with alpha-tocopherol protected the noradrenaline-induced responses against hypoxia in the substrate-free environment, However, at the EC50 concentration for protection of noradrenaline, alpha-tocopherol failed to protect the responses of each agent from the inhibitory effects of hypoxia, suggesting a mechanism of protection involving noradrenaline. 4. Drugs known to interfere with the disposition of noradrenaline in sympathetically innervated tissues, cocaine, hydrocortisone and tyramine did not affect the response to alpha-tocopherol. 5. Responses to calcium were unaffected by alpha-tocopherol in normoxia and hypoxia. 6. The protective action of alpha-tocopherol was not mimicked by the chromanol ring of the vitamin structure, Trolox C, suggesting that the vascular protection in hypoxia was not dependent on an antioxidant mechanism. 7. However, the glycolytic enzyme inhibitor, iodoacetic acid, prevented the protective action of the vitamin in hypoxia, suggesting that alpha-tocopherol enhanced noradrenaline-mediated activity in hypoxia through an iodoacetic acid-sensitive pathway.

Characteristics of the protective action of alpha-Tocopherol in vascular hypoxia

The functioning of the guinea-pig isolated portal vein was monitored by measuring spontaneous mechanical activity, responses to electrical stimulation and administered noradrenaline in normoxic conditions. The effect of hypoxia, induced by bubbling the physiological bathing solution with a 95% N(2)/5% CO(2) gas mixture, on the mechanical performance of the vein was then assessed. Spontaneous activity declined in hypoxia, with mean contraction tension reduced by 55 + or - 8.8%. The responses to electrical field stimulation (2-32 Hz, 0.7 msec. 70 V) were lowered by 14 + or - 4.6% but contractions produced by a range of noradrenaline concentrations (0.01-160 mu M) were unaffected by hypoxia. Substitution of glucose in the bathing solution with sucrose, a substrate unavailable to the cells for energy generation, produced a marked enhancement of the effect of hypoxia. Spontaneous activity was reduced by 76 + or - 8.3%, electrically-induced activity by 80 + or - 14.4% and noradrenaline-induced responses by 85 + or - 6.8%. Although in normoxia the activity and responses of the portal vein were unaffected by the presence of alpha-tocopherol, it significantly protected the functioning of the vein in hypoxic conditions. This effect was concentration-dependent within the range 10-160 mu M and was most marked when glucose was replaced by sucrose in the bathing solution.

Detection of very low level Plasmodium falciparum infections using the nested polymerase chain reaction and a reassessment of the epidemiology of unstable malaria in Sudan

We have used the nested polymerase chain reaction (PCR) to assay for low level Plasmodium falciparum infections that were below the threshold of detection of blood film examination. This revealed a substantial group of asymptomatic, submicroscopically patent infections within the population of a Sudanese village present throughout the year although clinical malaria episodes were almost entirely confined to the transmission season. In our September, January, April, and June surveys, the PCR-detected prevalences were 13%, 19%, 24%, and 19%, respectively. These figures reveal a much higher prevalence of dry season infection than previous microscopic surveys have indicated. Furthermore, 20% of a cohort of 79 individuals were healthy throughout the September to November transmission season but were PCR-positive for P. falciparum in a least one of a series of samples taken in the ensuing months. Levels of exposure to P. falciparum infection were therefore higher than was previously believed in this region, highlighting the fact that many individuals were infected but healthy for most of the year. The reservoir parasite population was thus larger and more stable than previously thought, a finding that is consistent with the high levels of genetic variation at polymorphic loci reported from analysis of P. falciparum parasites in this area.

Sclerosing peritonitis

Sclerosing peritonitis (SP) is an uncommon and devastating problem which involves the visceral and parietal peritoneal surfaces of the abdominal cavity. SP has been reported in association with peritoneal dialysis, with medications, and following peritonitis. No clear etiology or preventative treatment exists for this unusual problem. Herein, we report 3 cases with the unusual aspect of apparent progression of this fibrotic and sclerosing process after the termination of the peritoneal dialysis and successful renal transplantation. Each of these cases resulted in a mechanical small bowel obstruction secondary to a densely fibrosing and encasing peel of reactive connective tissue visibly different from the usual postoperative adhesions. Sclerosing peritonitis should be included in the differential diagnosis of a current peritoneal dialysis patient who exhibits signs of partial small bowel obstruction with a continual decrease in peritoneal clearance and/or successfully transplanted patients who had utilized peritoneal dialysis therapy in the past and now exhibit signs and symptoms of a mechanical small bowel obstruction.

The first t-test

The data with which Student illustrated the application of his famous distribution are examined from a number of aspects. Central to the discussion is the within-patient clinical trial at Kalamazoo whose results were published by Cushny and Peebles and misquoted by Student and Fisher. This trial is discussed from historical, pharmacological and statistical perspectives. Student's and Fisher's analyses and a more modern analysis by Preece are considered as is Cushny's and Peebles's interpretation. Brief biographies of the five physicians involved in running the trial are presented.

Deducing molecular similarity using Voronoi binding sites

We have devised a new measure of molecular similarity with respect to given simple partitions of space into regions. The similarity is determined by numerical integration of the difference in the optimal interaction between the two molecules and the regions over a large range of interaction parameter values. Compounds differing in empirical formula are differentiated by a single infinite region; cis/trans or ortho/meta/para isomers are distinguishable by two adjacent regions that are half-spaces; and stereoisomers require five regions. This can be viewed as a natural classification of isomers. The concept can also be applied to drug binding studies to determine which molecules may bind alike in a given biological receptor and to elucidate a necessary starting geometry when a binding site is modeled for inhibitors whose experimental binding energies are different.

Synthesis of tumour necrosis factor-alpha and interferons by mononuclear cells from Theileria annulata-infected cattle

Bovine macrophage-derived tumour necrosis factor-alpha/cachectin (TNF-alpha) was synthesized when peripheral blood mononuclear cells (PBMC) and purified adherent PBMC from naive and Theileria annulata-infected cattle were incubated in vitro with concanavalin A (Con-A) or bovine recombinant interferon gamma (Bo rIFN-gamma). TNF-alpha production was also induced when adherent PBMC were cultured with T. annulata macroschizont-infected cells. In contrast, non-adherent PBMC from sublethally infected cattle produced interferon (IFN) when incubated with Hu rIL-2, Con-A, phytohaemagglutinin (PHA) or T. annulata macroschizont-infected cells growing as cell lines in vitro. Whilst PBMC from lethally infected cattle spontaneously produced IFN-gamma during advanced stages of infection, the sera of such animals contained type 1 IFN (alpha/beta). IFN was also produced by T. annulata macroschizont-infected cell lines maintained in vitro. This work suggests that cytokines serve as crucial links between proliferating Theileira-infected cells and the characteristic clinical symptoms of tropical theileriosis.

Continuation of a case report

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Tropical theileriosis in Bos taurus and Bos taurus cross Bos indicus calves: response to infection with graded doses of sporozoites of Theileria annulata

This work extends basic knowledge of tropical theileriosis in taurine and crossbred cattle. Infection of Bos taurus and Bos taurus cross Bos indicus (Sahiwal) calves with graded doses of sporozoites of Theileria annulata (Hissar), an Indian stock of the parasite, showed the following to be dose dependent in both cattle types: the time to appearance and population size of macroschizonts, microschizonts and piroplasms, time and severity of pyrexia, anaemia manifested by erythrocyte counts and haematocrit. All infections were accompanied by a prompt and severe panleucopenia. This effect was dose related in both the taurine and the Sahiwal crossbred calves. Lymphocyte counts returned to preinfection levels in the blood of animals which recovered, but death from theileriosis was characteristically accompanied by a persistent and severe lymphocytopenia. Flow cytometry using monoclonal antibodies to bovine mononuclear cells was used to identify the lymphocyte subsets involved in lymphocytopenia. The outcome of infection was dose dependent in the crossbred calves but not in taurine calves. Although the results obtained did not differ qualitatively between the two cattle types, they provided some preliminary evidence for resistance to tropical theileriosis in Sahiwal crossbred calves.

Cytokines inhibit the development of trophozoite-infected cells of Theileria annulata and Theileria parva but enhance the proliferation of macroschizont-infected cell lines

The following bovine (Bo) and human (Hu) cytokines--Bo rTNF-a, Bo rIFN-g, Hu IFN-a, Hu rIL-1, Hu rIL-2--significantly inhibited the in vitro development of trophozoite-infected cells of three stocks of Theileria annulata and of Theileria parva (Muguga). However, none of these cytokines inhibited the proliferation of established T. annulata or T. parva macroschizont-infected cell lines. Indeed, Bo rTNF-a and Hu rIL-2 consistently enhanced the proliferation of macroschizont-infected cell lines of both species and the blastogenesis of uninfected lymphocytes in trophozoite-infected cultures. These results suggest that cytokines could help in resistance to challenge infections by preventing the further development of trophozoite-infected cells but provide no evidence that any of the above cytokines directly help to resolve primary infections by inhibiting the growth of macroschizont-infected cells. These findings also suggest that both TNF-a and IL-2 could play a role in the pathogenesis of Theileria infections by promoting the proliferation of macroschizont-infected cells and the associated lymphoid hyperplasia.

Beam obstruction hazard on Q-switched Nd-YAG ophthalmic lasers: a safety device for the Nanolas laser

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Surgical management of metastatic renal carcinoma of the spine

A total of 33 patients with renal cell carcinoma metastatic to the spine underwent spinal decompression over a 5-year period; 20 were operated on for neurologic dysfunction, and the remainder for pain alone. Surgery was performed anteriorly in 21, posteriorly in 9, and combined in 3 cases. The surgical approach was determined by the preoperative anatomic localization of the tumor. Of these patients 88% had fusions with instrumentation and polymethylmethacrylate; 88% of patients had partial or complete relief of pain; and 64% of bedridden patients subsequently were able to walk. Neurologic function improved in 60% of patients with a neurologic deficit; however, only 36% of incontinent patients regained bladder control. Survival averaged 8.0 +/- 1.5 months. Survival correlated with the degree of neurologic dysfunction and the presence of other known metastases. Recurrent cord compression developed in 49% of patients, usually at the same level; 9 of these 16 patients had repeat decompression, with similar operative results as the primary procedure in terms of pain and neurologic function. Blood loss was variable but often significant. Preoperative embolization appeared to be beneficial. Precise tumor localization preoperatively directing the surgical approach and better patient selection would likely improve results and decrease morbidity. Good palliation appeared to be achieved in regards to both pain relief and improved neurologic function.

Evaluating Patients with Chronic Pain and their Families: How you can recognize maladaptive patterns

Inclusion of family members in the assessment of patients with chronic pain can improve outcomes. Family functioning can be assessed in four basic areas: boundaries, power, communication, and intimacy. Early recognition of maladaptive patterns in the family allows the family physician to consider a variety of interventions ranging from educating the spouse to referring the family for therapy or multidisciplinary pain management.

A novel cervical dilatation force measurement instrument

A simple and robust instrument for cervical dilatation force measurement is described which measures axial insertion force but is not affected by lateral loads. The instrument is battery-powered, self-contained and displays actual axial force and peak axial force on digital liquid crystal displays.