Expert consensus on the management of infusion-related reactions (IRRs) in patients with sickle cell disease (SCD) receiving crizanlizumab: a RAND/UCLA modified Delphi panel

Crizanlizumab, a monoclonal antibody against P-selectin, has been shown to reduce vaso-occlusive crises (VOCs) compared to placebo in patients ≥ 16 years with sickle cell disease (SCD). However, there have been rare reports of patients experiencing severe pain and subsequent complications within 24 hours of crizanlizumab infusions. These events are defined as infusion-related reactions (IRRs). Informed by current literature and clinical experience, a group of content experts developed clinical guidelines for the management of IRRs in patients with SCD. We used the RAND/University of California, Los Angeles (UCLA) modified Delphi panel method, a valid, reproducible technique for achieving consensus. We present our recommendations for managing IRRs, which depend on patient characteristics including: prior history of IRRs to other monoclonal antibodies or medications, changes to crizanlizumab infusion rate and patient monitoring, pain severity relative to patient's typical SCD crises, and severe allergic symptoms. These recommendations outline how to evaluate and manage IRRs in patients receiving crizanlizumab. Future research should validate this guidance using clinical data and identify patients at risk for these IRRs.

DISPLACE Study Shows Poor Quality of Transcranial Doppler Ultrasound for Stroke Risk Screening in Sickle Cell Anemia

Children with sickle cell anemia (SCA) are at increased risk of stroke when compared to age-based counterparts. The Stroke Prevention Trial in Sickle Cell Anemia (STOP) previously demonstrated that with the use of transcranial Doppler ultrasound (TCD; Sickle Stroke Screen) and chronic red cell transfusion, the risk of stroke risk is reduced by over 90%. The STOP criteria detailed the type and method of measurement required; the time averaged mean maximum velocity (TAMMV). Unfortunately, it has been difficult to adhere to the appropriate TAMMV measurements. The objectives of this study were to assess the quality of TCD and transcranial Doppler imaging (TCDi) reports to determine report quality and accuracy. This is a sub-analysis of the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study. Over 12,000 TCD/TCDi reports were collected during this study from 28 institutions; 391 TCDs were reviewed for this sub-analysis. There was significant variation in which vessels were assessed, the velocities used to define abnormal results, and who was interpreting the scans. In 52% of reports, it was impossible to identify whether the TAMMV was what was measured. Similarly, it was only clear in 42% of reports that the TAMMV was used to interpret the exam as normal/abnormal. Given this inconsistency, we strongly recommend standardization of TCD/TCDi reporting, specialized training for those performing and interpreting the scans in the use of TCD/TCDi in patients with SCA, internal quality assurance, and institutional quality improvement work to ensure appropriate use of this potentially lifesaving technology.

Risk factors associated with in-hospital complications for pediatric sickle-cell disease-associated moyamoya syndrome: a nationwide cross-sectional study

PURPOSE

Sickle-cell disease-associated moyamoya syndrome (SCD-MMS) carries a high risk for recurrent strokes and cerebrovascular morbidity in children. However, few data are available about complications that occur in children hospitalized with SCD-MMS. The purpose of this analysis was to determine the risk factors for in-hospital complications in pediatric SCD-MMS admissions, and thus aid physicians in optimizing future treatment plans.

METHODS

A national database of pediatric hospital admissions was examined across the years 2003-2019. ICD-9 and ICD-10 diagnosis codes were analyzed to identify discharges with a primary diagnosis of SCD-MMS and identify in-hospital complications, defined as complication-associated diagnostic codes logged during the same admission. Patient demographics, comorbidities, and hospital characteristics were examined using univariate and multivariate logistic regression analyses to determine associations with in-hospital complications.

RESULTS

In total, 274 admissions with a primary diagnosis of SCD-MMS were identified. During 64 (23.4%) admissions, transfusion therapy was given, and in 86 admissions (31.4%), surgical revascularization was performed. In 10 admissions (3.6%), a total of 11 in-hospital complications were identified. After multivariate regression, both comorbid chronic lung disease (adjusted OR 5.3 [1.1, 26.9], P = 0.04) and surgical revascularization (adjusted OR 10.2 [2.0, 52.4], P = 0.006) were associated with development of complications.

CONCLUSIONS

In this nationwide database of pediatric SCD-MMS hospitalizations, comorbid chronic lung disease and surgical revascularization were associated with development of in-hospital complications. Patients with comorbid chronic lung disease or who are admitted for revascularization may warrant closer monitoring and greater medical optimization during the hospitalization.

Acute Chest Syndrome in Sickle Cell Disease

Acute chest syndrome (ACS) is the leading cause of mortality among individuals with sickle cell disease (SCD) accounting for 25% of all deaths. The etiologies and clinical manifestations of ACS are variable among children and adults, with a lack of clear risk stratification guidelines for the practicing clinician. In addition, the management of ACS is based on limited evidence and is currently guided primarily by expert opinion. This manuscript reviews the pathophysiology, risk factors, and current management strategies for ACS through a review of published data on this subject between 1988 and 2022. Blood transfusion is often used as a therapeutic intervention for ACS to increase blood's oxygen-carrying capacity and reduce complications by reducing hemoglobin S (HbS) percentage, based on the very low quality of the evidence about its efficacy. The benefit of RBC transfusion for ACS has been described in case series and observational studies, but randomized studies comparing simple transfusion vs. exchange transfusions for ACS are lacking. In this review, we conclude that the development of clinical and laboratory risk stratification is necessary to further study an optimal management strategy for individuals with ACS to avoid transfusion-related complications while minimizing mortality.

Barriers to hydroxyurea use from the perspectives of providers, individuals with sickle cell disease, and families: Report from a U.S. regional collaborative

Sickle cell disease (SCD) is an inherited blood disorder that affects about 100,000 people in the U.S., primarily Blacks/African-Americans. A multitude of complications negatively impacts quality of life. Hydroxyurea has been FDA approved since 1998 as a disease-modifying therapy for SCD, but is underutilized. Negative and uninformed perceptions of hydroxyurea and barriers to its use hinder adherence and promotion of the medication. As the largest real-world study to date that assessed hydroxyurea use for children and adults with SCD, we gathered and analyzed perspectives of providers, individuals with SCD, and families. Participants provided information about socio-demographics, hospital and emergency admissions for pain, number of severe pain episodes interfering with daily activities, medication adherence, and barriers to hydroxyurea. Providers reported on indications for hydroxyurea, reasons not prescribed, and current laboratory values. We found that hydroxyurea use was reported in over half of eligible patients from this large geographic region in the U.S., representing a range of sickle cell specialty clinical settings and practices. Provider and patient/caregiver reports about hydroxyurea use were consistent with one another; adults 26 years and older were least likely to be on hydroxyurea; and the likelihood of being on hydroxyurea decreased with one or more barriers. Using the intentional and unintentional medication nonadherence framework, we found that, even for patients on hydroxyurea, challenges to taking the medicine at the right time and forgetting were crucial unintentional barriers to adherence. Intentional barriers such as worry about side effects and “tried and it did not work” were important barriers for young adults and adults. For providers, diagnoses other than HgbSS or HgbS-β0 thalassemia were associated with lower odds of prescribing, consistent with evidence-based guidelines. Our results support strengthening provider understanding and confidence in implementing existing SCD guidelines, and the importance of shared decision making. Our findings can assist providers in understanding choices and decisions of families; guide individualized clinical discussions regarding hydroxyurea therapy; and help with developing tailored interventions to address barriers. Addressing barriers to hydroxyurea use can inform strategies to minimize similar barriers in the use of emerging and combination therapies for SCD.

Association of low serum albumin with venous thrombosis in pediatric patients

OBJECTIVES

The incidence of venous thromboembolism (VTE) in children is increasing, attributed in part to increased utilization of central venous catheters (CVCs). Children with protein losing disorders (PLDs) and low serum albumin may have an increased incidence of thrombosis. We sought to determine the prevalence of PLDs and hypoalbuminemia at the time of diagnosis of VTE in pediatric patients and its relationship to central venous catheters.

METHODS

We performed a single institution retrospective study of 65 consecutive hospitalized pediatric patients with an acute VTE. Data collected included clinical diagnoses, type of thrombosis, presence or absence of a CVC, and serum albumin level, if available.

RESULTS

Of 65 patients with acute VTE, 51 % (33/65) had catheter-related thrombosis (CRT), including 71 % (19/27) of patients <12 years of age and 37 % (14/38) of patients aged 12 to 23 (P = 0.008). Eleven VTEs occurred in patients with a diagnosis of a PLD; of these, ten (91 %) were CRT and one (9 %) was a non-CRT (P = 0.003). Serum albumin levels obtained within four days of diagnosis of VTE were available for 38 patients. An albumin level below the lower limit of the age-adjusted normal reference range was documented in 27/38 (71 %) patients with VTE compared to 1011/3028 (33 %) of all pediatric patients admitted to the hospital during a two-year period (P < 0.0001). Albumin levels were low in 19/22 (86 %) patients with CRT compared with 8/16 (50 %) patients with non-CRT (P = 0.019).

CONCLUSION

Low serum albumin levels are highly prevalent among pediatric patients with VTE, especially in those patients with CRT.

Study of Sleep Disorders among Young Children Using Hindi Translated and Validated Version of Pediatric Sleep Questionnaire

OBJECTIVE

The objective of this study is to assess the prevalence of sleep disorders among children aging between 4 and 9 years using Hindi version of Pediatric Sleep Questionnaire (PSQ).

METHODS

This study had two parts first, translation and validation of PSQ into Hindi language, and second, assessment of the prevalence of sleep disorders using PSQ Hindi version. Hindi PSQ was distributed in randomly chosen primary schools in a semi-urban area. The children were requested to get them filled by their parents. When the questionnaires were returned, responses were analyzed.

RESULTS

Most of the items of the Hindi version had perfect agreement with original questionnaire in a bilingual population (κ =1). Totally, 435 children were included in the field study having average age of 6.3 years. Obstructive sleep apnea was reported in 7.5% children; symptoms suggestive of restless legs syndrome were reported by 2%-3%; teeth grinding by 13.9% and sleep talking by 22.6% children.

CONCLUSION

PSQ Hindi version is a validated tool to screen for sleep disorders among children. Sleep disorders are fairly prevalent among young children in India.

Dok-1 negatively regulates platelet integrin αIIbβ3 outside-in signalling and inhibits thrombosis in mice

Adaptor proteins play a critical role in the assembly of signalling complexes after engagement of platelet receptors by agonists such as collagen, ADP and thrombin. Recently, using proteomics, the Dok (downstream of tyrosine kinase) adapter proteins were identified in human and mouse platelets. In vitro studies suggest that Dok-1 binds to platelet integrin β3, but the underlying effects of Dok-1 on αIIbβ3 signalling, platelet activation and thrombosis remain to be elucidated. In the present study, using Dok-1-deficient (Dok-1-/-) mice, we determined the phenotypic role of Dok-1 in αIIbβ3 signalling. We found that platelets from Dok-1-/- mice displayed normal aggregation, activation of αIIbβ3 (assessed by binding of JON/A), P-selectin surface expression (assessed by anti-CD62P), and soluble fibrinogen binding. These findings indicate that Dok-1 does not affect "inside-out" platelet signalling. Compared with platelets from wild-type (WT) mice, platelets from Dok-1-/- mice exhibited increased clot retraction (p < 0.05 vs WT), increased PLCγ2 phosphorylation, and enhanced spreading on fibrinogen after thrombin stimulation (p < 0.01 vs WT), demonstrating that Dok-1 negatively regulates αIIbβ3 "outside-in" signalling. Finally, we found that Dok-1-/- mice exhibited significantly shortened bleeding times and accelerated carotid artery thrombosis in response to photochemical injury (p < 0.05 vs WT mice). We conclude that Dok-1 modulates thrombosis and haemostasis by negatively regulating αIIbβ3 outside-in signalling.

The Association Between Psychological Factors and Orofacial Pain and Its Effect on Quality of Life: A Hospital Based Study

OBJECTIVE

To examine the hypothesis that psychological factors of psychological distress and perception of unhappiness in childhood are associated with self reported orofacial pain and to examine whether such patients have a poorer perception of their oral health related quality of life and if so then to what extent.

MATERIALS AND METHODS

A cross-sectional hospital based study was conducted in Hitkarini Dental College and Hospital, Jabalpur amongst 400 cases and 400 controls. Patients were included based on Locker and Slade's criteria. Patients were asked to complete 27 items Questionnaire which included the General Health Questionnaire to assess for psychological distress and Oral Health Impact Profile-14 for evaluating impact on quality of life. Bivariate and logistic regression analyses were performed to determine the degree of association between psychological factors, unhappy childhood and quality of life. P-value of less than 0.05 was considered statistically significant.

RESULTS

An increased propensity to report orofacial pain was seen for those individuals with higher levels of Psychological Distress and with perception of Unhappiness in Childhood. These individuals also reported with poorer perception of their oral health related Quality of Life.

CONCLUSION

The present study has shown relationship between Orofacial Pain, Quality of Life and Psychological Factors.

A Study on Duration of Effect of Transcutaneous Electrical Nerve Stimulation Therapy on Whole Saliva Flow

BACKGROUND

Saliva is a complex fluid, whose important role is to maintain the well being of oral cavity. Salivary gland hypofunction or hyposalivation is the condition of having reduced saliva production which leads to the subjective complaint of oral dryness termed xerostomia.(7) Management of xerostomia includes palliative therapy using topical agents or systemic therapy. Electrostimulation to produce saliva was studied in the past and showed moderate promise but never became part of mainstream therapy. Hence, this study was undertaken to evaluate the effect of transcutaneous electrical nerve stimulation (TENS) on whole salivary flow rate in healthy adults and to evaluate how long this effect of TENS lasts on salivary flow.

MATERIALS AND METHODS

One hundred healthy adult subjects were divided into five age groups with each group containing 20 subjects equally divided into males and females in each group. Unstimulated saliva was collected using a graduated test tube fitted with funnel and quantity was measured. Transcutaneous electrical nerve stimulation unit was activated and stimulated saliva was collected. Saliva was again collected 30 minutes and 24 hours post stimulation.

RESULTS

The mean unstimulated whole saliva flow rate for all subjects (n = 100) was 2.60 ml/5 min. During stimulation, it increased to 3.60 ± 0.39 ml/5 min. There was 38.46% increase in salivary flow. Ninety six out of 100 responded positively to TENS therapy. Salivary flow remained increased 30 minutes and 24 hours post stimulation with the values being 3.23 ± 0.41 ml/5 min and 2.69 ± 0.39 ml/5 min respectively. Repeated measures One way analysis of variance (ANOVA) test showed that the difference between these values were statistically significant.

CONCLUSION

Transcutaneous electrical nerve stimulation therapy was effective for stimulation of whole saliva in normal, healthy subjects and its effect retained till 30 minutes and a little up to 24 hours. Transcutaneous electrical nerve stimulation may work best synergistically with other sialagogues and can be used for the management of xerostomia.

Diagnostic outcome of preoperative coagulation testing in children

The value of routine coagulation testing instead of bleeding history alone in children, to predict bleeding risk prior to tonsillectomy and adenoidectomy has been questioned. Our objectives are to identify the causes of abnormal PT and/or aPTT in these patients, and to determine whether routine preoperative coagulation testing is effective in identifying children with a clinically significant coagulation abnormality prior to undergoing a procedure. In this study, data were extracted by chart review for 854 patients referred to the pediatric hematology service at Stony Brook University for the evaluation of an elevated PT and/or aPTT on preoperative testing. Seven hundred and ninety two of 854 reviewed charts (92.7%) contained sufficient data for analysis. On repeat testing, 393 (49.6%) had a laboratory abnormality identified. A potentially significant coagulation abnormality was identified in 32 of 792 patients (4%). For the remaining 760 patients, the most common diagnosis was a lupus anticoagulant (n = 98, 24.6%) or a "presumed" lupus anticoagulant (n = 166, 41.6%). A positive personal or family bleeding history was documented in 268 patients (268/792 = 33.8%). Of these patients, only 107 (39.9%) had an abnormality identified on further work-up. Seventeen of the 32 patients with clinically significant bleeding disorders identified were found to have a positive bleeding history (17/32 = 53.1%). Routine preoperative coagulation testing identifies only a small number of children at increased risk for surgical bleeding. However, a "positive" bleeding history identifies only 60% of children found to have a clinically significant coagulation abnormality. Routine preoperative coagulation testing may serve as a useful adjunct to clinical history.

Abstract 170: Differential Effects of Atorvastatin and Digeranyl Bisphosphonate on Hemostasis and Thrombosis in Hypercholesterolemic Mice

Background and Hypothesis

Statins inhibit HMG-CoA reductase, leading to decreased production of cholesterol and other isoprenoids. There is growing evidence that statins have protective effects on arterial thrombosis through pleiotropic mechanisms that may be independent of their cholesterol lowering effects. The antithrombotic effects of statins have been proposed to be related in part to diminished synthesis of geranyl-geranyl pyrophosphate (GGPP). To test this hypothesis, we determined the hemostatic and thrombotic effects of atorvastatin and digeranyl bisphosphonate (DGBP), a specific inhibitor of geranyl-geranyl pyrophosphate synthase, in apolipoprotein E-deficient (ApoE-/-) mice.

Methods

Tissue levels of GGPP and its precursor farnesyl pyrophosphate (FPP) were measured by HPLC. ApoE-/- mice were treated with either vehicle, atorvastatin (50 mg/kg/d), or DGBP (0.4 mg/kg/d) subcutaneously for 7 days. Susceptibility to thrombotic occlusion of the carotid artery was measured in response to injury with FeCl 3 . Tail-transection bleeding time and platelet clot retraction were also assessed.

Results

Compared with vehicle- or atorvastatin-treated mice, DGBP- treated mice had elevated levels of FPP in heart (P<0.001) and lung (P<0.001) and decreased levels of GGPP in heart (P<0.01) and liver (P<0.01). The time to stable occlusion of the carotid artery was prolonged in atorvastatin-treated mice compared with vehicle-treated mice (8.6±2.4 vs. 5.3±0.3 minutes; P<0.05). In contrast, DGBP-treated mice were not protected from carotid artery thrombosis (6.8±0.9 minutes). Bleeding times were markedly prolonged in DGBP-treated mice (388±88 seconds) compared with atorvastatin- (98±11 seconds) or vehicle-treated (150±91 seconds) mice (P<0.05). Platelet clot retraction also was delayed in DGBP-treated mice compared with atorvastatin or vehicle-treated mice (P<0.05).

Conclusions

Inhibition of GGPP production causes impairment of hemostasis but does not prevent arterial thrombosis in hypercholesterolemic mice. The differential effects of DGBP and atorvastatin suggest that the antithrombotic effects of statins are independent of geranyl-geranyl-mediated processes.

Outcome following saphenopopliteal surgery: a prospective observational study

Objectives

High recurrence rates following small saphenous varicose vein surgery have been reported. The aim of this study was to ascertain initial success rates following saphenopopliteal junction (SPJ) surgery using pre- and postoperative duplex scanning.

Methods

A prospective study was performed on patients with ultrasound-proven SPJ reflux. Patients underwent preoperative duplex skin marking and a postoperative quality assurance scan.

Results

Ninety procedures were performed in 88 patients. The SPJ was successfully ligated in 87 (96.7%) cases. Reflux was completely abolished in 51 (56.7%) cases, but persisted solely in the small saphenous vein (SSV) in 32.2%. Subsequently, 10 consecutive patients underwent 11 SPJ ligations with stripping of the SSV. Follow-up ultrasound scan demonstrated successful ligation of the SPJ and elimination of superficial venous reflux.

Conclusion

This study demonstrates that preoperative duplex SPJ marking results in a high percentage of successful ligation. Given that residual persistent reflux was avoided in patients who underwent stripping of the SSV, we propose that patients who require SPJ surgery undergo duplex marking along with specific consideration with regard to treatment of the residual SSV.

Life-threatening haemorrhage secondary to nicorandil-induced severe peri-anal ulceration

Nicorandil-induced ulceration is rare but has been reported at multiple sites throughout the gastrointestinal tract. We report a life-threatening complication of such ulceration - catastrophic per-rectal haemorrhage requiring emergency surgery with no prior symptoms. Whilst nicorandil should be considered in cases of chronic peri-anal and peristomal ulceration which fail to respond to conventional treatments, this case highlights its importance in the setting of acute surgical presentations.

Complete clinical response to neoadjuvant chemoradiotherapy in patients with rectal cancer: opinions of British and Irish specialists

INTRODUCTION

Advances in neoadjuvant treatment have highlighted the phenomenon of complete clinical response (CCR) in a proportion of patients with rectal cancer. Radical surgery may be associated with a poor functional outcome and quality of life and has a small but significant risk of mortality. This study aimed to assess opinion of colorectal surgeons on issues surrounding the question of nonoperative management in patients who demonstrate complete response after neoadjuvant therapy.

METHOD

A questionnaire was sent to members of the Association of Coloproctology of Great Britain and Ireland regarding investigations, clinical management, pathological assessment and oncological outcome in rectal cancer patients with a complete response to neoadjuvant chemoradiotherapy.

RESULTS

A total of 122 consultants responded (26% response rate). Most surgeons (58%) would not consider conservative management of patients with a complete response and even more (69%) expressed that they would never discuss nonoperative management in patients with rectal cancer who are fit for curative surgery. Over 70 different combinations of investigations and imaging modalities were suggested to define a CCR. Eighty-six per cent of consultants felt that a pathology report stating no evidence of residual adenocarcinoma did not rule out the presence of tumour cells and all respondents estimated the percentage of patients with pathological complete response as < 20%.

CONCLUSIONS

No consensus exists as to what defines a complete response and at present there is resistance to offering nonoperative management in selected patients. With improvements in neoadjuvant treatment modalities, it will be increasingly important to consider nonoperative management in the future.

Publication outcome for research presented at the Vascular Society of Great Britain and Ireland annual meetings

BACKGROUND The Vascular Society of Great Britain and Ireland (VSGBI) annual meeting is a major international vascular surgery conference. Studies suggest that the percentage of presentations that result in full-text publications are a measure of the quality of the meeting. We investigated the publication outcome of abstracts presented to the VSGBI in 2001 and 2002. MATERIALS AND METHODS We retrospectively identified abstracts from the conference programmes and conducted a detailed electronic Medline and PubMed search to determine publication. We collected data regarding the study design, subject matter,publishing journal, time to publication, institution of origin, impact factors and RAE levels. RESULTS There were 63 publications from 106 abstracts (59.4%), with a median impact factor of 3.507. Prospective observational studies accounted for 20.6% of publications, with abdominal aortic aneurysms being the commonest subject matter(34.9%). The median time to publication was 12 months, with the European Journal of Vascular and Endovascular Surgery publishing 33.3% of the articles. Leicester achieved the highest number of publications and the majority of work came from centres with Research Assessment Exercise (RAE) level scores of 4, university centres accounted for 74.6% of publications. CONCLUSIONS We conclude that when compared to equivalent meetings in other specialties and geographical regions, the annual meeting of the VSGBI is of the very highest quality.

How Should a Candidate Assess Varicose Veins in the MRCS Clinical Examination? A Vascular Viewpoint

INTRODUCTION

Varicose veins are a common problem and, therefore, regularly feature in the vascular bay of the MRCS clinical examination. Candidates are still being instructed to perform tests in the examination that are considered by many to be obsolete and inaccurate. Using the current cohort of vascular examiners, we aim to clarify which tests a candidate should be performing when assessing varicose veins. We also aim to assess basic surgical trainees' experience in the use of hand-held Doppler (HHD).

MATERIALS AND METHODS

Postal questionnaires were sent to all English College Court examiners with a declared vascular interest to gain their opinion on what tests should be used in the vascular bay to assess primary varicose veins. E-mail questionnaires were also sent to basic surgical trainees to assess their experience in the use of hand-held Doppler to assess varicose veins.

RESULTS

There was a 100% response rate from the examiners with 93%, 86% and 79% feeling that clinical examination, HHD examination of the SFJ and HHD examination of the SPJ, respectively, should form part of the examination of primary varicose veins in the vascular bay. Only 50% indicated the Trendelenburg test and cough impulse and 57% believed the tap test should form part of the examination of varicose veins. Of the BSTs, 53% believed they could examine varicose veins with HHD. Of the BSTs who could use HHD, 74% had held a vascular SHO post.

DISCUSSION

Published data and opinion show many consultant surgeons have totally abandoned the use of the Trendelenberg, cough, tap and Perthes tests and support the opinion that HHD increases the accuracy of the examination of varicose veins. This study shows the opinions of the examiners supports the evidence-based recommendations that, in the light of easily accessible HHD, the older tests are now outdated. The majority of BSTs who were able to use HHD had held a vascular SHO post (74%) but otherwise it was unlikely that the BST would be comfortable with this skill.

CONCLUSIONS

The Brodie-Trendelenburg (tourniquet) test, cough impulse and tap test are outdated but candidates should be aware of the principles and failings behind them. In the MRCS clinical examination, candidates should examine varicose veins by means of clinical examination and HHD as this is now accepted standard practice. To aid candidate education, the HHD technique should replace traditional clinical tests which continue to be taught in medical school and remain within the classical surgical text books.

Opposing regulation of cell proliferation by retinoic acid and the serotonin2B receptor in the mouse frontonasal mass

Development of the frontonasal mass (FNM), branchial arches, heart, and limbs depends on neural crest-mediated epithelial-mesenchymal (E-M) interactions. Teratogenesis by retinoic acid (RA) or blockade of serotonergic (5-HT) signaling by the pan-5-HT(2) receptor antagonist, ritanserin, perturbs development of these embryonic structures. In both cases, resulting phenotypes include forebrain and olfactory placode anomalies, malformations of the face, eye and lens, as well as posterior neural tube and cardiac defects. Similar sites of malformations, together with the presence of RA response elements in the 5-HT(2B) receptor promoter, have led to the suggestion that a negative regulatory relationship may exist between RA and 5-HT(2)-mediated 5-HT signaling at sites of E-M interaction (Choi et al. 1997); however, another possibility is that RA and 5-HT act independently as opposing signals to regulate development of common embryonic targets. Together with recent evidence for opposite effects on chondrogenic differentiation in hindlimb micromass cultures (Bhasin et al. 2003a), results of the present study raise the possibility that these pathways may act as opposing signals for common targets in the mouse embryo. The RA receptors, co-factors and metabolic enzymes, and 5-HT(2B) receptors were found to be are coordinately expressed at sites of E-M interaction, including the FNM, in the embryonic day (E)10.5 mouse. Cell proliferation experiments using [(3)H]thymidine incorporation demonstrated that RA or activation of 5-HT(2B) receptors caused opposite effects in FNM explants, namely stimulation or inhibition of cell proliferation, respectively, 5-HT(2B) receptor activation did not appreciably alter patterning in FNM explants. While RA has been shown to regulate lateral patterning in the FNM (LaMantia et al. 2000), 5-HT(2B) receptor activation did not alter patterning in FNM explants. Quantification of 5-HT(2B) receptor transcripts by real-time PCR provided no evidence of negative regulation of 5-HT(2B) receptor expression by RA in FNM explants, although preliminary studies using in situ hybridization had suggested that this was a possibility in both explants and RA teratogenized embryos. Future studies using quantitative PCR may still show this to be the case in teratogenized embryos. Together with the finding of coordinate expression of 5-HT(2B )receptors and RA signaling molecules, results of the present study suggest that RA, and 5-HT mediated by 5-HT(2B )receptors, may act as opposing signals to regulate cell proliferation during craniofacial development in the mouse embryo.

Differential regulation of chondrogenic differentiation by the serotonin2B receptor and retinoic acid in the embryonic mouse hindlimb

Retinoic acid (RA) synthesizing and metabolizing enzymes are coordinately expressed with serotonin 2B (5-HT2B) receptors at sites of epithelial-mesenchymal (E-M) interaction in the mouse embryo (Bhasin et al., 1999). The promoter of the 5-HT2B receptor contains potential RA response element (RAREs) as well as an AP-2 site. Because both retinoid and serotonergic signaling have been implicated in the regulation of chondrogenic differentiation, the present study investigated whether these signals may work together to regulate this morphogenetic process in hindlimb bud micromass cultures. Results indicate that 5-HT promotes [35S]sulfate incorporation (chondrogenic differentiation) by activation of 5-HT2B receptors, which use the mitogen activated protein kinase (p42 MAPK) signal transduction pathway, whereas RA dose-dependently inhibits sulfate incorporation and promotes expression of RARbeta, which could lead to inhibition of p38 MAPK. No evidence was found to support the possibility that RA negatively regulates expression of 5-HT2B receptors. Taken together, these results suggest that 5-HT and RA may act as opposing signals to regulate chondrogenic differentiation in the developing hindlimb, possibly mediated by different MAPK signal transduction pathways.

Mesenchymal/epithelial regulation of retinoic acid signaling in the olfactory placode

We asked whether mesenchymal/epithelial (M/E) interactions regulate retinoic acid (RA) signaling in the olfactory placode and whether this regulation is similar to that at other sites of induction, including the limbs, branchial arches, and heart. RA is produced by the mesenchyme at all sites, and subsets of mesenchymal cells express the RA synthetic enzyme RALDH2, independent of M/E interactions. In the placode, RA-producing mesenchyme is further distinguished by its coincidence with a molecularly distinct population of neural crest-associated cells. At all sites, expression of additional RA signaling molecules (RARalpha, RARbeta, RXR, CRABP1) depends on M/E interactions. Of these molecules, RA regulates only RARbeta, and this regulation depends on M/E interaction. Expression of Fgf8, shh, and Bmp4, all of which are thought to influence RA signaling, is also regulated by M/E interactions independent of RA at all sites. Despite these common features, RALDH3 expression is distinct in the placode, as is regulation of RARbeta and RALDH2 by Fgf8. Thus, M/E interactions regulate expression of RA receptors and cofactors in the olfactory placode and other inductive sites. Some aspects of regulation in the placode are distinct, perhaps reflecting unique roles for additional local signals in neuronal differentiation in the developing olfactory pathway.

Neisseria meningitidis lipopolysaccharide modulates the specific humoral immune response to neisserial porins but has no effect on porin-induced upregulation of costimulatory ligand B7-2

The role of lipopolysaccharide (LPS) in the specific humoral response to meningococcal porins was investigated by measuring anti-PorA or -PorB antibody levels in mice immunized with wild-type meningococcal strain H44/76 or with its recently described LPS-negative mutant. Two murine strains were used for these immunizations: C3H/HeJ, which is LPS hyporesponsive, or C3H/HeOuJ, which is LPS responsive. A high level of anti-PorB immunoglobulin G (IgG) response was induced in both strains of mice immunized with either organism. The response induced by the wild-type strain was greater in C3H/HeOuJ mice than in C3H/HeJ mice, while the response induced by the LPS-negative mutant was similar in the two murine strains. Additionally, the anti-PorB response was similar in C3H/HeJ mice immunized with either bacterial strain. In general, the anti-PorA IgG response was lower than the anti-PorB response. These findings indicate that the presence of LPS is not essential for the induction of an antineisserial porin humoral response but can augment such a response. To determine whether LPS has any effect on the B-cell-stimulatory effect of neisserial porins (essential for the adjuvant activity of neisserial porins), B cells from both murine strains were incubated with outer membrane complexes (OMCs) prepared from strain H44/76 and its LPS-negative mutant. OMCs from either meningococcal strain were able to increase the surface expression of the costimulatory ligand B7-2 on B cells from either murine strain. Consistent with previously reported findings, LPS does not significantly affect the ability of neisserial porins to induce the costimulatory ligand B7-2.

Staphylococcus aureus Cap5O has UDP-ManNAc dehydrogenase activity and is essential for capsule expression

The Staphylococcus aureus serotype 5 capsular polysaccharide (CP5) has a repeating unit composed of (-->4)-3-O-acetyl-beta-D-ManNAcA-(1-->4)-alpha-L-FucNAc (1-->3)-beta-D-FucNAc-(1-->)(n). Sixteen chromosomal genes (cap5A through cap5P) are involved in the synthesis of CP5. We recently demonstrated that Cap5P, a 2-epimerase, catalyzes the conversion of UDP-N-acetyl glucosamine (UDP-GlcNAc) to UDP-N-acetylmannosamine (UDP-ManNAc). In this study, we show that UDP-ManNAc is oxidized to UDP-N-acetylmannosaminuronic acid (UDP-ManNAcA) by a UDP-ManNAc dehydrogenase encoded by S. aureus cap5O. We expressed Cap5O in Escherichia coli and purified the recombinant protein. The UDP-ManNAc dehydrogenase activity of purified Cap5O was assessed by incubating Cap5P and UDP-GlcNAc (to produce UDP-ManNAc), together with Cap5O, NAD(+), and a reducing agent. Enzymatic activity was quantitated indirectly by measuring the increase in absorbance at 340 nm resulting from NADH formation. The product of the reaction was confirmed as UDP-ManNAcA by gas chromatography-mass spectroscopy. A cap5O mutation, created by deletion of 727 bp in the 5' end of the gene, was introduced by allelic replacement into S. aureus Reynolds, rendering it CP5 negative. Mice inoculated intravenously or subcutaneously with the wild-type strain Reynolds had greater numbers of S. aureus recovered from their kidneys (P = 0.019) or their subcutaneous abscesses (P = 0.0018), respectively, than did animals inoculated with the cap5O mutant. The results of this study indicate that S. aureus cap5O is essential for capsule production and that capsule promotes staphylococcal virulence in mouse models of abscess formation.

Mesenchymal/epithelial induction mediates olfactory pathway formation

In the olfactory pathway, as in the limbs, branchial arches, and heart, mesenchymal/epithelial induction, mediated by retinoic acid (RA), FGF8, sonic hedgehog (shh), and the BMPs, defines patterning, morphogenesis, and differentiation. Neuronal differentiation in the olfactory epithelium and directed growth of axons in the nascent olfactory nerve depend critically upon this inductive interaction. When RA, FGF8, shh, or BMP signaling is disrupted, distinct aspects of olfactory pathway patterning and differentiation are compromised. Thus, a cellular and molecular mechanism that facilitates musculoskeletal and vascular development elsewhere in the embryo has been adapted to guide the differentiation of the olfactory pathway in the developing forebrain.

Staphylococcus aureus cap5P encodes a UDP-N-acetylglucosamine 2-epimerase with functional redundancy

The serotype 5 capsule gene cluster of Staphylococcus aureus comprises 16 genes (cap5A through cap5P), but little is known about how the putative gene products function in capsule biosynthesis. We propose that the N-acetylmannosaminuronic acid (ManNAcA) component of the S. aureus serotype 5 capsular polysaccharide (CP5) is synthesized from a UDP-N-acetylglucosamine (UDP-GlcNAc) precursor that is epimerized to UDP-N-acetylmannosamine (UDP-ManNAc) and then oxidized to UDP-ManNAcA. We report the purification and biochemical characterization of a recombinant UDP-GlcNAc 2-epimerase encoded by S. aureus cap5P. Purified Cap5P converted approximately 10% of UDP-GlcNAc to UDP-ManNAc as detected by gas chromatography-mass spectrometry. The epimerization of UDP-GlcNAc to UDP-ManNAc occurred over a wide pH range and was unaffected by divalent cations. Surprisingly, CP5 expression in S. aureus was unaffected by insertional inactivation of cap5P. Sequence homology searches of the public S. aureus genomic databases revealed the presence of another putative UDP-GlcNAc 2-epimerase on the S. aureus chromosome that showed 61% identity to Cap5P. Redundancy of UDP-GlcNAc 2-epimerase function in S. aureus was demonstrated by cloning the cap5P homologue from strain Newman and complementing an Escherichia coli rffE mutant defective in UDP-GlcNAc 2-epimerase activity. Our results confirm the putative function of the S. aureus cap5P gene product and demonstrate the presence of a second gene on the staphylococcal chromosome with a similar function.

Identification of a gene essential for O-acetylation of the Staphylococcus aureus type 5 capsular polysaccharide

The Staphylococcus aureus serotype 5 capsular polysaccharide (CP5) has a trisaccharide repeating unit of (-->4)-3-O-Ac-beta-D-ManNAcAp-(1-->4)-alpha-L-FucNAcp-(1-->3 )-beta-D-FucNAcp-(1-->). Tn918 mutagenesis of strain Reynolds yielded a mutant that produced wild-type levels of O-deacetylated CP5. The site and orientation of the single transposon insertion in mutant JL232 were determined by analysis of Southern blots and amplification of DNA flanking the transposon. DNA sequencing revealed that Tn918 was inserted within an open reading frame of 627 bp. The predicted amino acid sequence encodes a protein of approximately 26 kDa with homology to members of the NodL-LacA-CysE family of bacterial acetyltransferases. Southern blot analysis showed that genes similar to cap5H were present only in strains of S. aureus belonging to capsular serotypes 2, 4 and 5. In an in vitro assay, the parental strain was more resistant to opsonophagocytic killing than the mutant strain. In a mouse model of staphylococcal infection, the parental strain was able to seed the bloodstream from the peritoneal cavity and colonize the kidneys more efficiently than the O-deacetylated mutant. When cap5H was provided to the mutant in trans, it fully restored CP5 O-acetylation. The virulence of the complemented mutant strain closely approximated that of the parental strain.

Apolipoprotein E gene expression in various tissues of mouse and regulation by estrogen

Apolipoprotein (apo) E is associated with several classes of lipoproteins and serves as a ligand for the receptor mediated uptake of cholesterol-rich particles by hepatocytes and peripheral tissues. Variant forms of apo E is also associated with dyslipidemia and late-onset of Alzheimer's Disease (AD). We report here expression of apoE in various mouse tissues, and regulation of apoE in liver, kidney, brain and testes by supraphysiological doses of estrogen. ApoE mRNA was quantified by RNase protection assay and translatable apoE mRNA by in vitro translation. As an internal control the levels of beta-actin mRNA were also quantified. Highest levels of apoE were expressed in liver (220-280 pg/mu g RNA) with negligible levels in small intestine. Brain expressed highest levels of total (35-40 pg/mu g RNA) and translatable apoE mRNA next only to liver. Other tissues that expressed relatively higher levels of apoE were adrenals, testes and ovary. ApoE was also found to be expressed in heart, lung, kidney and spleen. Regulation of apoE gene expression by estrogen (3 mu g 17beta-estradiol/ g body weight/ day for 5 consecutive days) was studied in liver, kidney, brain and testes of 4 mouse strains. Hepatic apoE mRNA did not change significantly in any of the mouse strains following estradiol administration. Of note was significant increases in the levels of brain apoE mRNA in the strain C3H. These studies demonstrate that estrogen regulates apoE gene expression in a tissue-specific manner in mice, and increases in apoE mRNA in the brain by estrogen may have implications in late-onset of Alzheimer's Disease.

Evidence for a weak adaptive response to alkylation damage in Vibrio cholerae

Wild-type Vibrio cholerae cells, when adapted by a stepwise treatment with sub-lethal concentrations of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), acquired resistance to killing and mutagenesis by subsequent challenges with higher concentrations of MNNG. This was also seen in the rec isogenic strain indicating that the observed phenomenon was not due to the induction of SOS functions. Further, the adapted cells of both the wild-type and rec strains could reactivate lethally alkylated phages with equal efficiency. Increased resistance of adapted cells correlated with the induction of a 17-kDa DNA methyltransferase, capable of repairing O6-methylguanine lesions in DNA. This induced methyltransferase was found to be antigenically unrelated to the Escherichia coli methyltransferase (Ada protein) as determined by Western blotting with polyclonal antiserum raised against the E. coli protein. Even though no counterpart of the constitutively expressed methyltransferase (Ogt) of E. coli could be detected in V. cholerae, several lines of evidence pointed towards the presence of an E. coli alk A-like gene in the organism.

Studies on the genesis of Vibrio cholerae O139: identification of probable progenitor strains

Four lines of evidence suggest that the recent outbreak strains of Vibrio cholerae O139 could have emerged from serogroup O1 strains typified by isolates M01 and M0477 described in this paper, which are neither truly classical nor truly E1 Tor in their biotype attributes. Firstly, like all O139 isolates, these O1 strains, isolated in Madras during and before the O139 outbreak, were resistant not only to polymyxin B but also to all biotype-specific choleraphages, i.e. classical phage phi 149 and E1 Tor phages e4 and e5. Secondly, the restriction fragment pattern (RFP) polymorphism displayed by these strains for the cholera toxin (ctx) gene, were identical with those produced by O139 isolates but were different from those of O1 type strains, namely V. cholerae 569B (classical) and V. cholerae MAK757 (E1 Tor). Thirdly, all the O139 isolates and the two O1 isolates carried an identical large number of copies of cholera toxin gene in their chromosomes. Finally, the outer-membrane protein profiles of strains M01 and M0477 were identical to those of O139 isolates but were different from those displayed by strains 569B and MAK757.