Association of left atrial ejection fraction and cardiovascular outcomes in Asian patients with hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): National University of Singapore Yong Loo Lin School of Medicine's Junior Academic Fellowship Scheme

Background

The optimal method of risk stratification of hyp­ertrophic cardiomyopathy (HCM) patients, especially in the Asian population, is unknown. Left atrial ejection fraction (LAEF) is an emerging risk marker for cardiovascular outcomes. This study aimed to investigate whether LAEF was associated with cardiovascular outcomes in Asian patients with HCM.

Methods

This was a retrospective cohort study performed in a tertiary academic centre involving 291 consecutive patients diagnosed with HCM between 2010 and 2017. We collected the relevant clinical characteristics of these patients and retrospectively analysed the index transthoracic echocardiograms for novel left atrial indices including LAEF. We obtained the maximum (LAVmax) and minimum left atrial volumes (LAVmin) using the biplane method of disks in apical 4- and 2-chamber views. LAEF was derived by dividing the difference between LAVmax and LAVmin by LAVmax. We assessed the patients for outcomes of (1) heart failure requiring admission, and (2) a composite of adverse outcomes including all-cause mortality, ventricular tachycardia / ventricular fibrillation (VT/VF) events, appropriate device therapy if an implantable cardioverter defibrillator (ICD) was implanted, stroke and heart failure hospitalization.

Results

The patients had a mean age of 59.0 ± 16.7 years-old at diagnosis and had a male preponderance (71.2%). The most common comorbidities were hypertension, diabetes mellitus and ischemic heart disease. On univariable logistic regression analysis, maximum and minimum left atrial volume index (LAVI) as well as LAEF showed a significant association with heart failure and the predefined composite outcome. On Cox regression analysis adjusting for variables of age, sex, left ventricular ejection fraction (LVEF), left ventricular maximal wall thickness >30mm, significant left ventricular outflow tract (LVOT) gradient of > 30mmHg and more than moderate mitral regurgitation, maximum and minimum LAVI as well as LAEF retained an association with heart failure admission but only minimum LAVI and LAEF were associated with the composite outcome [(OR 0.019, 95% CI 0.02-0.230, p=0.002), (OR 0.226, 95% CI 0.053-0.960, p=0.044), (OR 1.030, 95% CI 1.016-1.045, p<0.001), and (OR 1.016, 95% CI 1.005-1.026, p=0.004) respectively].

Conclusion

LAEF was an independently associated with congestive heart failure as well as a composite of adverse outcomes in Asian patients with HCM.

Evaluating the Initiation of Sodium/Glucose Cotransporter 2 Inhibitors within 2 Weeks of an Acute Hospital Admission: A Systematic Review and Meta-Analysis of Nine Clinical Trials

OBJECTIVE

Recent studies have increasingly shown the benefits of using sodium/glucose cotransporter 2 inhibitor (SGLT2i). However, there are concerns regarding the initiation of SGLT2i during acute hospital admissions due to the potential increased risk of complications. We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of SGLT2i initiation within 2 weeks of an acute hospital admission.

METHODS

Four electronic databases (PubMed, Embase, Cochrane, and Scopus) were searched for articles published from inception up to 27 March 2021 that evaluated the efficacy and/or safety of SGLT2i initiation within 2 weeks of an acute hospital admission. Random-effects pair-wise meta-analysis models were utilized to summarize the studies. The protocol was registered with PROSPERO (CRD42021245492).

RESULTS

Nine clinical trials were included with a combined cohort of 1,758 patients. Patients receiving SGLT2i had a mean increase in 24-h urine volume of +487.55 mL (95% CI 126.86-848.25; p = 0.008) compared to those not started on SGLT2i. Patients with heart failure treated with SGLT2i had a 27% relative risk reduction in rehospitalizations for heart failure, compared to controls (risk ratio 0.73; p = 0.005). There were no differences in other efficacy and safety outcomes examined.

CONCLUSION

There was no increased harm with initiation of SGLT2i within 2 weeks of an acute hospital admission, and its use reduced the relative risk of rehospitalizations for heart failure in patients with heart failure. It was also associated with increased urine output. However, current evidence pool is limited, especially in specific population subtypes.

Comparing Sacubitril/Valsartan Against Sodium-Glucose Cotransporter 2 Inhibitors in Heart Failure: A Systematic Review and Network Meta-analysis

BACKGROUND AND OBJECTIVE

In recent trials, sodium-glucose cotransporter 2 (SGLT2) inhibitors proved effective as treatment for heart failure. However, the relative efficacy of sacubitril/valsartan against SGLT2 inhibitor in patients with heart failure remains unknown. Hence, we performed a network meta-analysis to compare the effects of sacubitril/valsartan against SGLT2 inhibitors on cardiovascular outcomes in patients with heart failure.

METHODS

Four electronic databases (PubMed, Embase, Cochrane, SCOPUS) were searched for randomised-controlled trials (RCTs) published from 1st January 2000 to 25th September 2021. Two additional systematic reviews were conducted for RCTs of enalapril and valsartan to establish a common comparator arm. Frequentist network meta-analysis models were utilised to summarise the studies.

RESULTS

Twenty-five RCTs were included, comprising a combined cohort of 47,275 patients. Network meta-analysis demonstrated that compared to SGLT2 inhibitors, sacubitril/valsartan achieved a larger hazard rate reduction in the composite of heart failure hospitalisation and cardiovascular death (hazard ratio [HR]: 0.86; 95% CI 0.75-0.98), cardiovascular death (HR: 0.78; 95% CI 0.65-0.94), and a larger mean change in systolic blood pressure at 8 or more months (weighted mean difference [WMD]: - 7.08 mmHg; 95% CI - 8.28 to - 5.89). There were no significant differences in treatment effects across heart failure hospitalisation, all-cause mortality, diastolic blood pressure at 12 weeks, and systolic blood pressure at 2-4 months. In patients with heart failure with reduced ejection fraction, sacubitril/valsartan achieved a 20% hazard rate reduction for cardiovascular death compared to SGLT2 inhibitors.

CONCLUSIONS

In patients with heart failure, sacubitril/valsartan was demonstrated to be superior to SGLT2 inhibitors in the treatment effect for the composite of heart failure hospitalisation and cardiovascular death, cardiovascular death, and long-term blood pressure.

Comparing the clinical outcomes across different sodium/glucose cotransporter 2 (SGLT2) inhibitors in heart failure patients: a systematic review and network meta-analysis of randomized controlled trials

PURPOSE

Empagliflozin, dapagliflozin, canagliflozin, and ertugliflozin have been shown in randomized controlled trials to improve cardiovascular, metabolic, and renal outcomes in heart failure patients. To date, there has not been any meta-analysis examining the differences in clinical outcomes across different SGLT2 inhibitors in heart failure patients.

METHODS

Four electronic databases (PubMed, Embase, Cochrane, SCOPUS) were searched on 13 September 2020 for articles published from 1 January 2000 to 13 September 2020 examining the effect of SGLT2 inhibitors on cardiovascular, renal, and metabolic outcomes in heart failure patients. Frequentist network meta-analysis was performed on extracted data.

RESULTS

Ten randomized controlled trials were included with a combined cohort of 15,373 patients. In heart failure patients, frequentist network meta-analysis demonstrated no demonstrable difference in treatment effect across the SGLT2 inhibitors for heart failure hospitalization, cardiovascular deaths, composite of cardiovascular deaths and heart failure hospitalizations, all-cause mortality, and a composite of cardiovascular deaths and non-fatal myocardial infarction and non-fatal stroke. There was no demonstrable difference in treatment effect for worsening renal function or the weighted mean difference for weight, hemoglobin A1c, and systolic blood pressure.

CONCLUSIONS

There were no demonstrable treatment differences across SGLT2 inhibitors across cardiovascular, renal, and metabolic outcomes, although this needs to be interpreted considering the wide confidence intervals, limited number of included studies, and heterogeneity present. Future research of different SGLT2 inhibitors in head-to-head studies is warranted to determine if there is a drug class effect.

Notch1 inactivation promotes invasion and metastasis of nasopharyngeal carcinoma cells partly through Slug activation

Nasopharyngeal carcinoma (NPC) is a rare form of the head and neck cancer of the epithelial lining of the nasopharynx and exhibits the highest metastatic rate among head and neck cancers. Underlying mechanisms of metastasis remain largely unknown. Here, we explored whether Notch1 affects the invasion and metastasis of NPC cells. In vitro migration and invasion capacities were evaluated after the knockdown of Notch1 expression in NPC cells. To investigate the role of Notch1 in in vivo metastasis, we examined the metastatic ability to the lungs following administration of cancer cells via mouse tail vein. The expression of epithelial-mesenchymal transition (EMT) markers associated with Notch1-mediated metastasis was investigated, and their roles in metastasis and relationship with Notch1 expression were investigated. Suppression of Notch1 expression increased the ability of NPC cells to invade Matrigel in vitro. Knockdown of Notch1 expression in NPC cells resulted in extensive lung metastasis in a mouse model and increased the mRNA expression of Slug in NPC cells. Slug-specific RNA interference resulted in the loss of the metastatic and invasion capacities in Notch1-suppressed NPC cells. These findings show that Notch1 has a significant suppressive role in the regulation of metastasis in NPCs, suggestive of its prudent use in clinical trials.

The LIM-only transcription factor LMO2 determines tumorigenic and angiogenic traits in glioma stem cells

Glioblastomas (GBMs) maintain their cellular heterogeneity with glioma stem cells (GSCs) producing a variety of tumor cell types. Here we interrogated the oncogenic roles of Lim domain only 2 (LMO2) in GBM and GSCs in mice and human. High expression of LMO2 was found in human patient-derived GSCs compared with the differentiated progeny cells. LMO2 is required for GSC proliferation both in vitro and in vivo, as shRNA-mediated LMO2 silencing attenuated tumor growth derived from human GSCs. Further, LMO2 is sufficient to induce stem cell characteristics (stemness) in mouse premalignant astrocytes, as forced LMO2 expression facilitated in vitro and in vivo growth of astrocytes derived from Ink4a/Arf null mice and acquisition of GSC phenotypes. A subset of mouse and human GSCs converted into vascular endothelial-like tumor cells both in vitro and in vivo, which phenotype was attenuated by LMO2 silencing and promoted by LMO2 overexpression. Mechanistically, the action of LMO2 for induction of glioma stemness is mediated by transcriptional regulation of Jagged1 resulting in activation of the Notch pathway, whereas LMO2 directly occupies the promoter regions of the VE-cadherin gene for a gain of endothelial cellular phenotype. Subsequently, selective ablation of human GSC-derived VE-cadherin-expressing cells attenuated vascular formation in mouse intracranial tumors, thereby significantly prolonging mouse survival. Clinically, LMO2 expression was elevated in GBM tissues and inversely correlated with prognosis of GBM patients. Taken together, our findings describe novel dual roles of LMO2 to induce tumorigenesis and angiogenesis, and provide potential therapeutic targets in GBMs.

Forced arterial suction thrombectomy with the penumbra reperfusion catheter in acute basilar artery occlusion: a retrospective comparison study in 2 Korean university hospitals

BACKGROUND AND PURPOSE

A performance of forced arterial suction thrombectomy was not reported for the treatment of acute basilar artery occlusion. This study compared revascularization performance between intra-arterial fibrinolytic treatment and forced arterial suction thrombectomy with a Penumbra reperfusion catheter in patients with acute basilar artery occlusion.

MATERIALS AND METHODS

Fifty-seven patients with acute basilar artery occlusion were treated with intra-arterial fibrinolysis (n = 25) or forced arterial suction thrombectomy (n = 32). Baseline characteristics, successful revascularization rate, and clinical outcomes were compared between the groups.

RESULTS

Baseline characteristics, the frequency of patients receiving intravenous recombinant tissue plasminogen activator, and mean time interval between symptom onset and femoral puncture did not differ between groups. The forced arterial suction thrombectomy group had a shorter procedure duration (75.5 minutes versus 113.3 minutes, P = .016) and higher successful revascularization rate (88% versus 60%, P = .017) than the fibrinolysis group. Fair outcome, indicated by a modified Rankin Scale 0-3, at 3 months was achieved in 34% of patients undergoing forced arterial suction thrombectomy and 8% of patients undergoing fibrinolysis (P = .019), and the mortality rate was significantly higher in the fibrinolysis group (25% versus 68%, P = .001). Multiple logistic regression analysis identified the forced arterial suction thrombectomy method as an independent predictor of fair outcome with adjustment for age, sex, initial NIHSS score, and the use of intravenous recombinant tissue plasminogen activator (odds ratio, 7.768; 95% CI, 1.246-48.416; P = .028).

CONCLUSIONS

In acute basilar artery occlusion, forced arterial suction thrombectomy demonstrated a higher revascularization rate and improved clinical outcome compared with traditional intra-arterial fibrinolysis. Further clinical trials with the newer Penumbra catheter are warranted.

Oct4 is a critical regulator of stemness in head and neck squamous carcinoma cells

Cancer stem cells (CSCs) have been suggested as responsible for the initiation and progression of cancers. Octamer-binding transcription factor 4 (Oct4) is an important regulator of embryonic stem cell fate. Here, we investigated whether Oct4 regulates stemness of head and neck squamous carcinoma (HNSC) CSCs. Our study showed that ectopic expression of Oct4 promotes tumor growth through cyclin E activation, increases chemoresistance through ABCC6 expression and enhances tumor invasion through slug expression. Also, Oct4 dedifferentiates differentiated HNSC cells to CSC-like cells. Furthermore, Oct4(high) HNSC CSCs have more stem cell-like traits compared with Oct4(low) cells, such as self-renewal, stem cell markers' expression, chemoresistance, invasion capacity and xenograft tumorigeneity in vitro and in vivo. In addition, knockdown of Oct4 led to markedly lower HNSC CSC stemness. Finally, there was a significant correlation between Oct4 expression and survival of 119 HNSC patients. Collectively, these data suggest that Oct4 may be a critical regulator of HNSC CSCs and its targeting may be potentially valuable in the treatment of HNSC CSCs.

Comparison of the Incidence of parenchymal hematoma and poor outcome in patients with carotid terminus occlusion treated with intra-arterial urokinase alone or with combined IV rtPA and intra-arterial urokinase

BACKGROUND AND PURPOSE

Patients with acute CTO generally have a poor prognosis, despite IV or IA thrombolytic treatment. The goal of this study was to analyze the results of patients with CTO who had IA urokinase treatment with or without initial IV rtPA based on a bridging protocol.

MATERIALS AND METHODS

Sixteen consecutive patients with acute ischemic stroke due to CTO who had combined IV and IA or a single IA thrombolytic treatment were enrolled. The baseline characteristics and prognosis were described. The patients who did and did not develop a PH shortly after treatment were compared.

RESULTS

The mean age was 66.4 years, and the median initial NIHSS score was 17. The median dose of IA urokinase was 320,000 U, and recanalization (TICI grade II-III) was achieved in 12 patients (75%). However, 5 patients died and 10 patients had poor prognosis with mRS 5-6 at discharge. Six patients (37.5%) with a PH had a higher NIHSS score 1 day after treatment (26.7 versus 13.6, P = .002), and they had more frequent mortality (66.7% versus 10.0%, P = .018) and worse prognosis (mRS 5-6; 100% versus 40%, P = .016) at discharge than patients without PH.

CONCLUSIONS

Patients with CTO who received IA urokinase treatment based on a bridging protocol had a poor prognosis. The development of PH might affect this outcome.

Ministry of Health clinical practice guidelines: management of gambling disorders

The Ministry of Health (MOH) has published clinical practice guidelines on Management of Gambling Disorders to provide doctors and patients in Singapore with evidence-based guidance on the management of gambling disorders. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Management of Gambling Disorders for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=26136). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Aptasensors: a review

Aptamers are a promising class of agents for biomolecules detection due to their small size, chemical stability and cost effectiveness over conventional bioreceptors such as antibodies. Recent advances in micro/nano-fabrication and biotechnology have driven active participation of engineers and molecular biologists in the development of aptasensors. This review examines aptasensors from a developer standpoint discussing surface immobilization techniques and mechanisms used to detect biomolecular interactions in the context of biotechnology and nanomedicine. The factors that affect accuracy, sensitivity and stability of aptasensors are also addressed.

Case report. Tuberculous cervical lymphadenitis mimicking metastatic lymph nodes from papillary thyroid carcinoma

We report two unusual cases of tuberculous lymphadenitis mimicking metastatic lymph nodes from papillary thyroid carcinoma (PTC). Pre-operative ultrasonography of the cervical nodes suggested a metastasis with cystic necrosis and calcification in PTC patients, but permanent pathology revealed tuberculosis lymphadenitis after neck dissection. In cases suspicious for metastatic cervical nodes in patients with PTC, fine-needle aspiration cytology may be indicated for the differential diagnosis of tuberculosis lymphadenitis, especially in those who have experienced tuberculosis in the past.

Acute renal failure following detergent ingestion

A 42-year-old woman with a history of depression and epilepsy ingested two types of household detergent and developed gastrointestinal symptoms, and subsequently acute renal failure. Coingestants included nontoxic quantities of paracetamol and therapeutic doses of sodium valproate and fluoxetine. The patient developed acute renal failure, and also had fever and unilateral ear inflammation. The acute renal failure resolved four days later. Patients presenting with detergent poisoning are typically screened and treated for gastrointestinal and respiratory toxicity. We discuss the mechanism of development of acute renal failure in our patient, review the literature linking detergent poisoning and nephrotoxicity, and propose a direct relationship between detergent poisoning and acute renal failure.

Central lymph node metastases in unilateral papillary thyroid microcarcinoma

BACKGROUND

The indications for and appropriate extent of prophylactic central lymph node (CLN) dissection for clinically node-negative patients with unilateral papillary thyroid microcarcinoma (PTMC) are unknown.

METHODS

The frequency, patterns and predictive factors for CLN metastases in 86 patients with unilateral PTMC and a clinically node-negative neck were analysed with respect to age and sex; metastasis, age, completeness, invasiveness, size (MACIS) score; tumour size; number and location of tumours; presence of ipsilateral CLN metastases; and presence of lymphovascular or capsular invasion. All patients underwent total thyroidectomy and CLN dissection.

RESULTS

Twenty-seven (31 per cent) of 86 patients had metastatic CLNs: 18 ipsilateral and nine bilateral. Univariable analysis suggested male sex and tumour size greater than 0.5 cm to be significant factors in predicting ipsilateral CLN metastases. Only ipsilateral nodal positivity was a significant predictor of contralateral CLN metastases in multivariable analysis (P = 0.007).

CONCLUSION

CLN metastases are relatively common in PTMC.

Unilateral, clinically T2N0, squamous cell carcinoma of the tongue: surgical outcome analysis

To determine the survival rate and analyse the predicting factors of recurrence in patients with unilateral, clinically T2N0 squamous cell carcinoma (SCC) of the tongue which does not cross the midline, a retrospective analysis of 32 such consecutive, previously untreated, cases was performed. All patients were initially treated by surgery between January 1992 and May 2004. All patients had neck dissections: 12 continuous, 20 discontinuous, 24 bilateral and 8 unilateral. Fourteen patients (44%) received adjunctive postoperative radiotherapy. Occult metastatic rates were 34% and 4% in ipsilateral and contralateral neck, respectively. Patients with pN0 cancer had a better 5-year disease-specific survival rate than those with pN+ cancer (85% versus 41%, P=0.005). Twelve patients (38%) had recurrences after the initial treatment. The recurrence rate was significantly higher in patients with pathologic nodal metastasis, peroral resection of the primary tumour or discontinuous neck dissection. The results suggest that the most effective surgical methods for treating unilateral T2N0 SCC of the tongue which does not cross the midline are: pull-through approach for primary lesion instead of peroral approach; continuous rather than discontinuous neck dissection and ipsilateral elective rather than bilateral routine elective neck dissection.

Akinetic mutism after right internal watershed infarction

We describe a 72-year-old man who developed akinetic mutism following a cerebrovascular accident involving his right internal watershed area and responded well to dopaminergic agonists. We discuss this rare condition and the unusual unilateral location of the lesion.

Perivascular–submandibular lymph node metastasis in squamous cell carcinoma of the tongue and floor of mouth

AIMS

The goal of this study was to investigate the incidence of occult metastasis in perivascular lymph node and nodal recurrence in these nodal pads in squamous cell carcinoma (SCC) of the tongue and floor of mouth.

METHODS

We performed a prospective analysis of the incidence of an occult metastasis in the perivascular lymph nodes in 55 patients (41 with an oral tongue carcinoma and 14 with a mouth floor carcinoma) who underwent an elective supraomohyoid neck dissection (SOHND) for SCC of the tongue and floor of mouth, from 1997 to 2002. 99 SOHND procedures were performed as follows: 72 in tongue carcinomas and 27 in the mouth floor carcinomas.

RESULT

Clinically occult, but pathologically positive perivascular lymph nodes occurred in four of 72 of the tongue carcinomas and two of 27 of the mouth floor carcinomas. The incidence of the regional recurrence at level I was three of 45.

CONCLUSIONS

This preliminary report reveals a small incidence of perivascular lymph-node metastases and the infrequent nodal recurrence in this area after SOHND in early-staged tongue and floor of mouth SCC.

Reduced expression of junctional adhesion molecule and platelet/endothelial cell adhesion molecule-1 (CD31) at human vascular endothelial junctions by cytokines tumor necrosis factor-alpha plus interferon-gamma Does not reduce leukocyte transmigration under flow

The combination of tumor necrosis factor (TNF)-alpha plus interferon (IFN)-gamma has been shown previously to promote redistribution of platelet/endothelial cell adhesion molecule-1 (PECAM-1) (CD31), junctional adhesion molecule (JAM), and VE-cadherin away from lateral junctions of human umbilical vein endothelial cell monolayers. In parallel, neutrophil transmigration was significantly reduced. Because PECAM-1 and JAM have been implicated in leukocyte transmigration, the observed redistribution by cytokine activation was presumed to represent the mechanism causing decreased transmigration under static conditions. The current results confirm that culture of human umbilical vein endothelial cells with TNF-alpha plus IFN-gamma caused a decrease in surface-expressed and junctional-localized JAM and PECAM-1, but did not cause decreased leukocyte transmigration in an in vitro flow assay. Furthermore, blocking monoclonal antibody to PECAM-1 still significantly reduced monocyte transmigration, demonstrating that it retains a functional role even though its levels were reduced and redistributed away from junctions, whereas a panel of monoclonal antibodies to JAM failed to reduce leukocyte transmigration. Given the alterations in junction protein location, permeability function was assessed. IFN-gamma alone or TNF-alpha plus IFN-gamma significantly increased permeability, but TNF-alpha alone did not, suggesting lack of correlation between transmigration and loss of permeability. In conclusion, cytokine activation induced loss and redistribution of PECAM-1 and JAM away from lateral junctions, but per se does not negatively regulate either neutrophil or monocyte transmigration under flow.

IL-12, STAT4-dependent up-regulation of CD4(+) T cell core 2 beta-1,6-n-acetylglucosaminyltransferase, an enzyme essential for biosynthesis of P-selectin ligands

TCR activation of naive T cells in the presence of IL-12 drives polarization toward a Th1 phenotype and synthesis of P- and E-selectin ligands. Fucosyltransferase VII (Fuc-T VII) and core 2 beta-1,6-N-acetylglucosaminyltransferase (C2GnT) are critical for biosynthesis of selectin ligands. P-selectin glycoprotein ligand-1 is the best characterized ligand for P-selectin and also binds E-selectin. The contributions of TCR and cytokine signaling pathways to up-regulate Fuc-T VII and C2GnT during biosynthesis of E- and P-selectin ligands, such as P-selectin glycoprotein ligand 1, are unknown. IL-12 signals via the STAT4 pathway. Here, naive DO11.10 TCR transgenic and STAT4(-/-) TCR transgenic CD4(+) T cells were stimulated with Ag and IL-12 (Th1 condition), IL-4 (Th2), or neutralizing anti-IL-4 mAb only (Th0). The levels of Fuc-T VII and C2GnT mRNA in these cells were compared with their adhesive interactions with P- and E-selectin in vitro under flow. The data show IL-12/STAT4 signaling is necessary for induction of C2GnT, but not Fuc-TVII mRNA, and that STAT4(-/-) Th1 cells do not traffic normally to sites of inflammation in vivo, do not interact with P-selectin, and exhibit a partial reduction of E-selectin interactions under shear stress in vitro. Ag-specific TCR activation in CD4(+) T cells was sufficient to trigger induction of Fuc-TVII, but not C2GnT, mRNA and expression of E-selectin, but not P-selectin, ligands. Thus, Fuc-T VII and C2GnT are regulated by different signals during Th cell differentiation, and both cytokine and TCR signals are necessary for the expression of E- and P-selectin ligands.

Renal dysfunction in workers exposed to inorganic lead

INTRODUCTION

We studied the relationship between renal dysfunction and occupational lead exposure in a local factory.

MATERIALS AND METHODS

A cross-sectional study with a cohort component was conducted with 55 male workers of a factory producing PVC stabilisers as subjects. Workers from this factory have been followed up with 6-monthly blood lead measurements since 1982. Two indices of overall lead exposure, i.e. the number of times a worker's blood lead exceeded 40 micrograms/dL (PbB40) and cumulative blood lead index (PbBint), were obtained from this data. Recent blood lead concentration (PbB) was measured. 4-hour creatinine clearance and various other urinary and serum markers of renal dysfunction were used as effect indices.

RESULTS

There was no relationship between PbB and any of the renal markers. However, creatinine clearance decreased significantly (P < 0.001) with increasing PbB40 and PbBint after adjustment for age and smoking habits. Urinary albumin (Ualb), urinary alpha-1 microglobulin (U alpha 1m), urinary beta-2 microglobulin (U beta 2m) and urinary retinol-binding protein (URBP) increased significantly with both increasing PbB40 and PbBint. Total urinary activity of N-acetyl-beta-D-glucosaminidase (NAG-T) and its heat-stable isoenzyme (NAG-B) increased significantly with increasing PbB40. A significant difference in renal parameters occurred when PbB40 was 1 or more.

CONCLUSIONS

We have found a positive association between overall lead exposure and renal dysfunction. The renal parameters were significantly higher among those who had at least one episode of blood lead above 40 micrograms/dL. Our findings also strengthen the case for the use of Ualb, U alpha 1m, U beta 2m, URBP, NAG-T and NAG-B as early markers of lead nephropathy.

Frequency of cytochrome P450 2C9 mutant alleles in a Korean population

AIMS

To determine the frequencies of CYP2C9 variants in the Korean population and compare them with the frequencies in other ethnic populations.

METHODS

Genotyping of CYP2C9*2 and CYP2C9*3 allelic variants was carried out in 574 Korean subjects by PCR and restriction fragment length pattern analysis.

RESULTS

Thirteen of 574 subjects (2.3%) were heterozygous for CYP2C9*3 (Ile359Leu), but no subjects with a CYP2C9*2 allele or homozygous for CYP2C9*3 were identified. The allele frequency of CYP2C9*3 in Korean subjects (0.0113, 95% CI 0.0066-0.0193) was similar to that of other East Asian populations, but was considerably lower than that of Caucasian populations.

CONCLUSIONS

CYP2C9*3 seems to be an allelic variant related to the functional polymorphism of CYP2C9, but this variant is rarely seen among Koreans compared with Caucasians. Routine genotyping of the CYP2C9*2 allele is considered to be unnecessary in Korean and East Asians, because this allele appears to be extremely rare or absent in these populations.

Cross-sectional study of near-work and myopia in kindergarten children in Singapore

INTRODUCTION

In view of the high and increasing myopia rates amongst young Singaporean children, we aimed to assess the relationship between near-work and myopia in 414 pre-school children aged 4 to 6 years.

MATERIALS AND METHODS

We measured near-work indices such as tuition classes outside school and other possible risk factors via a questionnaire. We then measured myopia with a hand-held autorefractor.

RESULTS

Children who had 3 or more hours per week of near-work classes outside school had a higher rate [odds ratio 1.39 (95% confidence interval 1.02, 2.53)] of myopia.

CONCLUSIONS

This suggests that there may be an association between near-work and myopia, even at such a young age. Given the increasing emphasis on near-work in Singapore, it may be important to call for increased visual health awareness, although further studies will be needed to establish if near-work causes myopia.

Renal functional responses to centrally administered ouabain in anesthetized rabbits

The effects of intracerebroventricularly administered ouabain on renal function were studied in rabbits. Ouabain, when given intracerebroventricularly in doses ranging from 0.1 to 10 micrograms/kg, dose-dependently produced antidiuretic, antinatriuretic and antikaliuretic effects, along with decreases in renal perfusion and glomerular filtration rate. Systemic blood pressure also increased significantly in a dose-related fashion. No increase in free water reabsorption was noted. Intravenously administered ouabain (10 micrograms/kg) caused less pronounced antidiuresis and antinatriuresis, with the renal hemodynamics tending slightly to decrease. No significant increment of systemic blood pressure with intravenous ouabain was observed. In rabbits with one kidney denervated and the contralateral left intact, ouabain 10 micrograms/kg i.c.v. produced the typical renal effects on the intact kidney, while the denervated kidney responded with prominent natriuresis and diuresis, showing the maximal response in the second 10-min period after administration. Renal nerve activity increased significantly upon administration of ouabain 10 micrograms/kg i.c.v. and reached a peak at around 10 to 20 min after drug administration, a period in which the most remarkable antidiuresis and antinatriuresis is produced by i.c.v. ouabain. These observations suggest that the antidiuresis and antinatriuresis elicited by centrally administered ouabain results mainly from the decrease of renal hemodynamics, which is caused by the increased renal nerve activity.

Alpha4beta1-integrin activation is necessary for high-efficiency T-cell subset interactions with VCAM-1 under flow

OBJECTIVE

The purpose of this study was to examine the relationship between alpha4beta1-integrin state of activation on CD4+ T-cell subsets and their adhesive interaction to VCAM-1 under flow.

METHODS

Human CD4+ memory and naive T-cells were freshly isolated and effector-helper T-cell subsets. Th1 and Th2 cells, were differentiated in vitro from CD4+ naive T-cells. The expression of activation/ligand induced epitopes on beta1-integrins of each T-cell subset was assessed using mAb HUTS21 and mAb 15/7. T-cell subsets attachment and rolling on VCAM-1 was determined under defined flow conditions and the rates of attachment (ka), accumulation, and instantaneous rolling velocities were correlated to their beta1-integrin activation epitope expression.

RESULTS

A subset of memory T-cells constitutively express activation/ligand induced epitopes on beta1-integrins recognized by mAb HUTS21 and 15/7, whereas expression levels on naive T-cells is low or not detectable. Consistent with an activated phenotype, memory T-cells exhibit significantly higher rates of attachment and accumulation on VCAM-1 under flow as compared to naive T-cells. Interestingly, the expression of activation/ligand induced epitopes on beta1-integrins on Th2 cells and the ability of these cells to interact with VCAM-1 are comparable to memory T-cells. In contrast, Th1 cells did not interact as efficiently with VCAM-1, which correlated with lower expression of activation/ligand induced epitopes on these cells. VCAM-1 interactions are inhibited completely by pretreatment of the T-cells with blocking mAb to alpha4-integrins or beta1-integrins, indicating that alpha4beta1 is the predominant T-cell integrin involved.

CONCLUSIONS

Memory T-cells express constitutively active alpha4beta1-integrins, as compared to naive T-cells, which mediate high rates of initial attachment and sustained high-affinity adhesive interactions with VCAM-1 under flow conditions in vitro. Similarly, in vitro differentiated Th2 cells but not Th1 cells, which also express elevated levels of activated alpha4beta1-integrins, are capable of sustaining high-affinity adhesive interactions with VCAM-1. The differences observed in beta1-integrin activation on T-cell subsets may underlie selective recruitment patterns of T-cell subsets in vivo.

C-C and C-X-C chemokines trigger firm adhesion of monocytes to vascular endothelium under flow conditions

In summary, our findings indicate that specific chemokines that are elaborated by endothelial cells after cytokine or endotoxin activation can play an essential role in monocyte recruitment beyond their chemoattractant activities. We show that this action is to translate initial monocyte tethering into firm adhesion via rapid leukocyte integrin activation. The in vitro model presented here provides a sensitive system for investigating the modulating ability of chemokines and reveals an important biological effect that is not predicted by results in simpler in vitro assays, such as measurement of calcium transients or chemotaxis. The surprising finding that the C-X-C chemokine IL-8 can trigger monocyte firm adhesion to vascular endothelium suggests a potential role for this chemokine in monocyte recruitment and underscores the biological complexity of the chemokine family.

Acquisition of selectin binding and peripheral homing properties by CD4(+) and CD8(+) T cells

Different T cell subsets exhibit distinct capacities to migrate into peripheral sites of inflammation, and this may in part reflect differential expression of homing receptors and chemokine receptors. Using an adoptive transfer approach, we examined the ability of functionally distinct subsets of T cells to home to a peripheral inflammatory site. The data directly demonstrate the inability of naive T cells and the ability of effector cells to home to inflamed peritoneum. Furthermore, interleukin (IL)-12 directs the differentiation of either CD4(+) or CD8(+) T cells into effector populations that expresses functional E- and P-selectin ligand and that are preferentially recruited into the inflamed peritoneum compared with T cells differentiated in the presence of IL-4. Recruitment can be blocked by anti-E- and -P-selectin antibodies. The presence of antigen in the peritoneum promotes local proliferation of recruited T cells, and significantly amplifies the Th1 polarization of the lymphocytic infiltrate. Preferential recruitment of Th1 cells into the peritoneum is also seen when cytokine response gene 2 (CRG-2)/interferon gamma-inducible protein 10 (IP-10) is used as the sole inflammatory stimulus. We have also found that P-selectin binds only to antigen-specific T cells in draining lymph nodes after immunization, implying that both antigen- and cytokine-mediated signals are required for expression of functional selectin-ligand.

MCP-1 and IL-8 trigger firm adhesion of monocytes to vascular endothelium under flow conditions

Monocytes contribute to the development of atherosclerotic lesions in mouse models. The chemoattractant proteins (chemokines), monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8), are found in human atheroma, and mice lacking receptors for these chemokines are less susceptible to atherosclerosis and have fewer monocytes in vascular lesions. Although MCP-1 has a powerful effect on monocytes, IL-8 is thought to act predominantly on neutrophils and it is unclear how it could recruit monocytes. Here we investigate the ability of chemokines to control the interaction of monocytes under flow conditions with vascular endothelium that has been transduced to express specific leukocyte-adherence receptors. We find that MCP-1 and IL-8 can each rapidly cause rolling monocytes to adhere firmly onto monolayers expressing E-selectin, whereas related chemokines do not. These effects do not correlate with either the induction of a calcium transient or chemotaxis. We conclude that chemokines are important modulators of monocyte-endothelial interactions under flow conditions. Moreover, our finding that IL-8 is a powerful trigger for firm adhesion of monocytes to vascular endothelium reveals an unexpected role for this chemokine in monocyte recruitment.

Expression of functional selectin ligands on Th cells is differentially regulated by IL-12 and IL-4

Immune responses may be qualitatively distinct depending on whether Th1 or Th2 cells predominate at the site of Ag exposure. T cell subset-specific expression of ligands for vascular selectins may underlie the distinct patterns of recruitment of Th1 or Th2 cells to peripheral inflammatory sites. Here we examine the regulation of selectin ligand expression during murine T helper cell differentiation. Large numbers of Th1 cells interacted with E- and P-selectin under defined flow conditions, while few Th2 and no naive T cells interacted. Th1 cells also expressed more fucosyltransferase VII mRNA than naive or Th2 cells. IL-12 induced expression of P-selectin ligands on Ag-activated naive T cells, even in the presence of IL-4, and on established Th2 cells restimulated in the presence of IL-12 and IFN-gamma. In contrast, Ag stimulation alone induced only E-selectin ligand. Interestingly, restimulation of established Th2 cells in the presence of IL-12 and IFN-gamma induced expression of P-selectin ligands but not E-selectin ligands; IFN-gamma alone did not enhance expression of either selectin ligand. In summary, functional P- and E-selectin ligands are expressed on most Th1 cells, few Th2 cells, but not naive T cells. Furthermore, selectin ligand expression is regulated by the cytokine milieu during T cell differentiation. IL-12 induces P-selectin ligand, while IL-4 plays a dominant role in down-regulating E-selectin ligand.

Important contributions of P-selectin glycoprotein ligand-1-mediated secondary capture to human monocyte adhesion to P-selectin, E-selectin, and TNF-alpha-activated endothelium under flow in vitro

In this study, an in vitro flow model and a blocking mAb to P-selectin glycoprotein ligand-1 (PSGL-1) were used to define the role of PSGL-1 in monocyte attachment and rolling on E- and P-selectin and in attachment and accumulation on 6-h TNF-alpha-activated HUVEC. KPL1, an adhesion-blocking mAb directed against the tyrosine sulfate motif of PSGL-1, abolished monocyte-adhesive interactions with P-selectin, but only partially blocked monocyte interaction with E-selectin. Further analysis showed that on E-selectin, KPL1 blocked only secondary (i.e., monocyte/monocyte) interactions, but did not block primary (i.e., monocyte/E-selectin) interactions, with secondary adhesion accounting for 90% of the total adhesive interactions on either E- or P-selectin. On cytokine-activated HUVEC, monocytes initially attached and formed linear strings of adherent cells, which involved both primary and secondary adhesion. PSGL-1 or L-selectin mAb reduced string formation, and the combination of PSGL-1 and L-selectin mAb prevented monocyte strings and inhibited 86% of accumulation. Monocyte attachment and rolling on purified adherent monocytes were also critically dependent on PSGL-1 on the adherent monocytes. These studies document that secondary interactions between monocytes, mediated by PSGL-1, are crucial for monocyte initial attachment, rolling, and accumulation on activated endothelium under laminar shear flow.

Adhesion of monocytes to vascular cell adhesion molecule-1-transduced human endothelial cells: implications for atherogenesis

To study the role of vascular cell adhesion molecule-1 (VCAM-1) in monocyte recruitment and atherogenesis, we constructed a recombinant adenovirus, AdRSVrVCAM-1, carrying the rabbit VCAM-1 cDNA. We have previously shown that AdRSVrVCAM-1-transduced human umbilical vein endothelial cells (HUVECs) support the adhesion of CD4+ CD45RO+ memory T lymphocytes under laminar flow conditions. We now demonstrate that AdRSVrVCAM-1-transduced HUVECs support the adhesion of peripheral blood monocytes at a shear stress of < or = 1.5 dyne/cm2. Although VCAM-1 supported only firm adhesion of lymphocytes, it was able to mediate monocyte rolling, firm adhesion, and transmigration when expressed in the context of otherwise unactivated vascular endothelium. VCAM-1-transduced HUVECs supported the adhesion of as many as 4-fold more monocytes than T cells under laminar flow. The greater monocyte adhesion was explained at least in part by leukocyte-leukocyte interactions (secondary adhesions), which were not seen with T cells. These secondary monocyte interactions were specifically blocked by monoclonal antibodies to L-selectin and P-selectin glycoprotein ligand-1. These data demonstrate that VCAM-1 expressed in the context of unactivated vascular endothelium supports the adhesion of the leukocyte populations present in atherosclerotic plaque and may contribute to the predominance of monocytes over lymphocytes.

Pulmonary involvement by Hodgkin's disease mimicking pneumonia

A 24-year-old man who was initially thought to have nocardiosis of his mediastinal lymph node which progressed to involve his right lung, had to undergo a right pneumonectomy when he failed to respond to treatment with sulphadiazine. Histology of the right lung specimen and a subsequent axillary lymph node biopsy revealed that he actually had lymphocyte-depleted Hodgkin's disease.

A case of tracheal obstruction during oesophageal removal of a foreign body

A patient was admitted with an impacted foreign body in the oesophagus. Repeated attempts to remove it during oesophagoscopy proved difficult and caused obstruction of the trachea during manipulation of the foreign body. A smaller endotracheal tube was subsequently placed in the trachea relieving the obstruction.

Early experience of video-assisted thoracoscopic surgery

Consecutive 25 patients (M/F:18/7) underwent video-assisted thoracoscopic surgery (VATS) for various chest illnesses. These included nine cases of pneumothorax, three cases of pericardial effusion, three cases of pleural effusion, four cases of lung lesion requiring either incisional or excisional biopsy, two cases of empyema, one case of traumatic haemothorax, and three cases of mediastinal lesion. The mean age was 36.2 years (range 19-78 years). A total of forty-three procedures were performed. The mean durations of intrapleural chest-tube requirement and hospitalisation following VATS alone were 4.5 days (range: 0-13 days) and 8.3 days (range: 2-25 days) respectively. No intraoperative complication and VATS procedure-related mortality reported. Apart from simple analgesics such as paracetamol or tramadolol, no opiate analgesia was given to patients undergoing only VATS. The results support that VATS is a safe and effective procedure in the management of pulmonary, mediastinal, pericardial and pleural diseases and the treatment of persistent and recurrent spontaneous pneumothorax.

A comparison of alfentanil, esmolol, lidocaine, and thiopental sodium on the hemodynamic response to insertion of headrest skull pins

STUDY OBJECTIVES

To compare the effects of four techniques for preventing or blunting the hypertensive response to the insertion of Mayfield headrest skull pins: intravenous (IV) alfentanil (ALF), esmolol (ESM), thiopental sodium (TPL), and local anesthesia using plain lidocaine (Xylocaine; XYL).

DESIGN

Randomized open study.

PATIENTS

40 adult patients undergoing intracranial or spinal surgery requiring the use of Mayfield headrest skull pins for head positioning and immobilization.

INTERVENTIONS

20 minutes after anesthetic induction, and 2 to 3 minutes prior to the insertion of headrest skull pins, one of three drugs was administered IV: ALF 10 mcg/kg, ESM 1 mg/kg, or TPL 1.5 mg/kg. The fourth drug, XYL, was administered by injection into the scalp.

MEASUREMENTS AND MAIN RESULTS

Blood pressure and heart rate (HR) were recorded immediately prior to and after pin insertion with balanced general anesthesia, and at 30, 60, 120, and 180-second intervals after pin insertion. The measurements were compared with the immediate preinsertion values. In the ALF and XYL groups, there was no significant increase in mean arterial pressure (MAP) or HR for any of the measurement periods. MAP was elevated immediately on pin insertion and for up to 2 minutes in the TPL group, and for up to 3 minutes in the ESM group (p < 0.05). HR changes were seen in the TPL group for up to one minute (p < 0.05). Increases in systolic blood pressure were seen in the TPL and ESM groups for up to 3 minutes, and in diastolic blood pressure for up to 2 minutes (p < 0.05). No other significant changes were observed.

CONCLUSIONS

IV ALF and local injection of XYL in the scalp prevent the hemodynamic response to the insertion of skull pins in anesthetized patients. Neither ESM nor TPL prevented the hypertensive response. Local anesthetic injection into the scalp requires coordination between the anesthesiologist and surgeon, it carries the risk of needle stick injury, and it must be repeated if the surgeon repositions the headrest. The rapid onset and short half-life of ALF, coupled with the absence of hemodynamic effects at the dose used, makes this drug an alternative to the use of XYL injection.

Video-assisted thoracoscopic surgery for pneumothorax

Five cases of spontaneous pneumothorax were treated with video-assisted thoracoscopic surgery (VATS). These included four cases of recurrent pneumothorax and one case of persistent pneumothorax. The mean age was 33 years. The identified bullae were eliminated with either endoloop ligation (in one patient) or stapled excision (in four patients). There were no recurrences reported in a mean follow-up of 9.4 months. In conclusion, VATS offers an equally effective and less morbid alternative to open thoracotomy in the management of primary spontaneous pneumothorax.

The effect of acute hypocapnia on middle cerebral artery transcranial Doppler velocity during orthotopic liver transplantation: changes at reperfusion

This study examines the effects of acute hypocapnia, instituted prior to reperfusion of the graft liver, on the middle cerebral artery (MCA) Doppler blood flow velocity response to reperfusion during orthotopic liver transplantation in humans. Seventeen patients with chronic liver disease underwent continuous, noninvasive Doppler imaging of the MCA. Hyperventilation to an end-tidal Pco2 of 25 +/- 1 mm Hg was associated with a decrease in mean MCA flow velocity (FVm) from 51.6 +/- 5.7 to 37.0 +/- 3.3 cm/s (P < 0.05). After reperfusion, the Paco2 increased from 32 +/- 1 to 40 +/- 1 mm Hg (P < 0.05), mean arterial pressure (MAP) decreased from 76 +/- 3 to 60 +/- 2 mm Hg, and the FVm increased from 37.0 +/- 3.3 to 54.0 +/- 4.7 cm/s (P < 0.05). FVm increased postreperfusion despite prior hyperventilation, decreased MAP, and abrupt increases in central venous and pulmonary artery pressure, but FVm did not exceed the prereperfusion level. In 10 of the 17 patients, the baseline FVm versus Paco2 response slopes and Paco2 measured postreperfusion were used to predict the FVm response to Paco2 after reperfusion. The slopes were similar to those reported for anesthetized patients without liver disease. Predicted FVm exceeded measured FVm in 9 of the 10 patients. We conclude that mild hyperventilation prior to reperfusion of the graft liver prevents FVm increases above prereperfusion baseline level.

Intraoperative transesophageal echocardiography in orthotopic liver transplantation in a patient with hypertrophic cardiomyopathy

With improvements in the surgical technique for orthotopic liver transplantation, patients with significant underlying systemic disease are considered candidates for transplantation, thus increasing the complexity of the medical management of these patients and necessitating additional monitoring in order to minimize the anesthetic risk. We describe the anesthetic management of orthotopic liver transplantation for a patient with severe hypertrophic cardiomyopathy and mitral insufficiency. In this case, transesophageal echocardiography proved useful in the management of the postreperfusion period of the surgical procedure.