Immune reconstitution following bone marrow transplantation: comparison of recipients of T-cell depleted marrow with recipients of conventional marrow grafts

The reconstitution of hematopoietic cells and in vitro assays of immunologic function have been followed in leukemic patients after conventional bone marrow transplantation (BMT) (N = 34) and T-cell depleted BMT (N = 52) from human leukocyte antigen (HLA)-identical sibling donors. No effects of the T-cell depletion could be seen on the recovery of myeloid or lymphoid cells as measured by the day to engraftment or by the absolute number of cells through day 100. Normal numbers of lytically active natural killer cells returned the earliest and were rapidly followed in both groups of patients by the appearance of circulating B cells and normalization of the responses to B-cell mitogens. However, the recovery of normal T-cell proliferative responses were more delayed in recipients of T-cell depleted grafts. Significant quantitative differences were seen only during the first 3 months after transplantation. Neither the number of CD3+ T cells nor the ratio of CD4:CD8 positive cells differed markedly between the two transplant groups. Mitogen-induced immunoglobulin production by peripheral blood lymphocytes (PBL) from patients following T-cell depleted BMT was quantitatively less than that of conventional marrow recipients through the first year, with low normal IgM production reached by 4 to 6 months in both groups. IgG production reached low normal 7 to 9 months after conventional BMT but did not remain at this level until 1 year following either type of transplant. Assessment of the incidence of infections from the day the absolute neutrophil count reached 500 until day 180 after transplant revealed no significant differences between the two groups; indeed, the overall nonleukemic mortality was higher in the recipients of conventional bone marrow. Thus, in our series, the removal of mature cells from the marrow graft did not affect the rate or degree of recovery of myeloid and lymphoid cells but did affect the regeneration of in vitro T-cell dependent functions. We noted early quantitative differences and a delay in the normalization of the T-cell functions measured rather than prolonged absolute deficiencies. The in vitro deficiencies did not result in significant clinically apparent differences between the two groups.     

The changing face of gastroschisis and omphalocele in southeast Georgia

Objective: To document trends in the clinical characteristics of gastroschisis and omphalocele in southeast Georgia, USA, from 1994 to 2002.

Methods: All babies with an abdominal wall defect in a 19-county region were referred to one Perinatal Center for genetic counseling, level II ultrasound scans, pregnancy follow-up and delivery. Karyotyping was offered for omphalocele, advanced maternal age, family history predisposing to aneuploidy, and gastroschisis with an additional anomaly.

Results: There were 64 patients, 34 with gastroschisis and 30 with omphalocele. From 1994 to 2002, the birth prevalence of gastroschisis was 1:3600 and omphalocele 1:3400, but from 2000 to 2002, gastroschisis increased to 1:1667, while omphalocele increased to only 1:2709. Gender distribution was different: for gastroschisis the M:F ratio was 1:2.1; for omphalocele the ratio was 1.7:1. In the patients with omphalocele, 90% had an amniocentesis and 9/27 were aneuploid: five had trisomy 18, three had trisomy 13 and one had trisomy 21. Seventy-six per cent of the patients with omphalocele had associated anomalies, but only 17.6% of those with gastroschisis. Mothers whose babies had gastroschisis showed a trend to progressively younger age, while no such trend was observed among mothers whose babies had omphalocele.

Conclusion: The birth prevalence of abdominal wall defects in general is increasing, but more notably for gastroschisis. Maternal age continues to decrease for gastroschisis. In the study population, gender distribution showed a statistically significant variation between the defects.     

Does Minimal-Access Aortic Valve Replacement Reduce the Incidence of Postoperative Atrial Fibrillation?

As the most common sequela of cardiac valvular surgery, atrial fibrillation (AF) has an important impact on postoperative morbidity. Minimal-access aortic valve replacement (AVR), with purported benefits on operative outcomes, has emerged as an alternative to conventional AVR. We used meta-analysis to determine whether minimal access influences the incidence of postoperative AF after AVR. Further, we sought first to evaluate via sensitivity analysis the impact of any differences and to identify the sources of possible heterogeneity between studies; second, we sought to evaluate any indirect effect of minimal-access AVR on other surrogate outcomes related to postoperative AF. We identified 10 studies from 26 comparative randomized and nonrandomized reports that documented the primary outcome of interest: new-onset AF. Overall meta-analysis showed no significant difference between minimal-access and conventional AVR in the incidence of postoperative AF (odds ratio, 0.85; 2,262 patients; P=0.24; 95% confidence interval, 0.66–1.11). Nor were there any apparent differences in surrogate outcome measures of intensive care unit stay, total length of stay, or stroke among studies that displayed a notable difference in AF incidence between groups. Sensitivity analysis that included only high-quality studies similarly showed no significant difference in the incidence of AF and further showed several intraoperative variables as potential sources of heterogeneity between studies. Therefore, minimal access may not have a significant effect on postoperative AF. Future randomized studies must take into account the potential sources of heterogeneity identified here to better demonstrate any differences between the 2 approaches in the onset of AF.Key words: Aortic valve/surgery, aortic valve stenosis/surgery, atrial fibrillation/etiology/prevention & control, postoperative complications, surgical procedures, minimally invasiveAtrial fibrillation (AF) is an important complication of valvular heart surgery: the reported incidence is as high as 60%.^1–3 Postoperative AF can result in hemodynamic compromise, thromboembolic phenomena, and anxiety. Other sequelae include prolonged length of stay (LoS) and increased cost. Controversy exists concerning the benefits of a minimal-access approach for aortic valve replacement (AVR); it is important, therefore, to evaluate whether the minimal-access approach carries a different incidence of AF than does the conventional approach.Preoperative, intraoperative, and postoperative variables all affect the incidence of postoperative AF.^1,3–7 Therefore, the array of contributory pathophysiologic factors implicated in postoperative AF is diverse. It includes age- and hypertension-related structural changes in the atria, the effects of surgical manipulation of the heart or pericardium, the duration of myocardial ischemia, and the effects of systemic influences such as electrolyte imbalance, drug administration, and cardiopulmonary bypass (CPB)-related inflammatory effects.^8,9Minimal-access AVR (mAVR) offers apparent benefits in terms of postoperative morbidity, such as fewer respiratory complications and fewer patients transfused.^10–16 On the other hand, mAVR has been associated with longer CPB and aortic cross-clamp (CC) times and with a greater propensity for pleural and pericardial effusions.^14,15,17 We hypothesized that the incidence of AF after mAVR would relate to factors other than the technique of surgical access itself. To investigate this, we analyzed all studies in the surgical literature published in English that compared mAVR and conventional AVR (cAVR) with regard to the incidence of postoperative AF. We used a meta-analytical synthesis of data to examine the effects of minimal access on the incidence of AF, and we focused on the variables associated with AF, including the established preoperative predictors of postoperative AF and predictors that are related to intraoperative manipulation of the heart.     

Toll-like receptor 2, 3, and 4 expression and function in human airway smooth muscle

BACKGROUND: Host defense against microbial pathogens is elicited through the innate immune system by means of Toll-like receptors (TLRs). Airway smooth muscle cells (ASMCs) display proinflammatory and immunomodulatory functions. ASMCs might participate in airway inflammatory responses associated with innate immune activation. OBJECTIVES: We determined the effects of cytokines, TLR ligands, and corticosteroids on TLR expression and function in human ASMCs. METHODS: Real-time PCR and flow cytometry were used to assess TLR mRNA and protein expression, respectively. ASMCs were stimulated with TLR ligands, and chemokine release was measured by means of ELISA. RESULTS: ASMCs expressed TLR1 to TLR10 mRNA, and TLR2 and TLR3 protein expression was demonstrated. TNF-alpha and double-stranded RNA (dsRNA; TLR3 ligand) were potent inducers of TLR2 and TLR3 mRNA expression, and both stimuli had additive or synergistic effects with IFN-gamma on TLR2 and TLR4, but not TLR3, mRNA expression. Peptidoglycan (TLR2 ligand) and LPS (TLR4 ligand) weakly enhanced TLR2 mRNA expression. Peptidoglycan, dsRNA, and LPS induced IL-8 and eotaxin release, with dsRNA being most potent. dsRNA also modulated cytokine-induced chemokine release in a differential manner. Dexamethasone inhibited cytokine- and ligand-induced TLR2, TLR3, and TLR4 expression and chemokine release. However, dexamethasone potentiated TLR2 expression induced by combined IFN-gamma and TNF-alpha stimulation. CONCLUSION: Expression of TLR2, TLR3, and TLR4 is regulated by cytokines and TLR ligands, and their activation mediates chemokine release in ASMCs. CLINICAL IMPLICATIONS: Proinflammatory responses mediated by activation of pathogen-recognition receptors in ASMCs might contribute to infectious exacerbations of airway inflammatory conditions, such as asthma and chronic obstructive pulmonary disease.     

FLS simulator performance predicts intraoperative laparoscopic skill

Introduction Simulators are being used more and more for teaching and testing laparoscopic skills. However, it has yet to be firmly established that simulator performance reflects operative laparoscopic skill. The study reported here was designed to test the hypothesis that laparoscopic simulator performance predicts intraoperative laparoscopic skill. Methods A review of our prospectively maintained database identified 40 subjects who underwent Fundamentals of Lapraoscopic Surgery (FLS) skills testing and objective intraoperative assessments within the same 6-month period. Subjects consisted of 22 novice (postgraduate year [PGY] 1–2), 10 intermediate (PGY 3–4), and 8 experienced (PGY 5, fellows, and attendings) laparoscopic surgeons. Laparoscopic performance was objectively assessed in the operating room using the previously validated Global Operative Assessment of Laparoscopic Skill (GOALS). Analysis of variance (ANOVA) was used to compare mean FLS scores and mean GOALS scores across experience levels. The relationship between individual FLS scores and GOALS scores was assessed with linear regression analysis. A multivariate analysis evaluated FLS score and surgeon experience as predictors of intraoperative GOALS score. A receiver-operator curve (ROC) was constructed in order to define an FLS cutoff score that predicts intraoperative performance at or above the level of experienced surgeons. Significance was defined as p < 0.05. Results Mean FLS scores and mean GOALS scores increased with increasing experience. Individual FLS scores correlated significantly with intraoperative GOALS scores (0.77, p < 0.001). Multivariate analysis confirmed that FLS score is an independent predictor of intraoperative GOALS scores. The ROC identified an FLS cutoff score of 70 with optimal sensitivity (91%) and specificity (86%) for predicting a GOALS score at or above the level of experienced surgeons. Conclusions In this study sample, FLS simulator scores were independently predictive of intraoperative laparoscopic performance as measured by GOALS. More precisely, an FLS cutoff score of 70 optimized sensitivity and specificity for expert intraoperative performance. A larger prospective study is justified to validate these findings. Oral presentation, 2007 Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) Conference; Las Vegas, Nevada This work was supported by an unrestricted educational grant from Tyco Healthcare, Canada     

Identification of a tumor suppressive critical region mapping to 3p14.2 in esophageal squamous cell carcinoma and studies of a candidate tumor suppressor gene, ADAMTS9

A gene critical to esophageal cancer has been identified. Functional studies using microcell-mediated chromosome transfer of intact and truncated donor chromosomes 3 into an esophageal cancer cell line and nude mouse tumorigenicity assays were used to identify a 1.61 Mb tumor suppressive critical region (CR) mapping to chromosome 3p14.2. This CR is bounded by D3S1600 and D3S1285 microsatellite markers. One candidate tumor suppressor gene, ADAMTS9, maps to this CR. Further studies showed normal expression levels of this gene in tumor-suppressed microcell hybrids, levels that were much higher than observed in the recipient cells. Complete loss or downregulation of ADAMTS9 gene expression was found in 15 out of 16 esophageal carcinoma cell lines. Promoter hypermethylation was detected in the cell lines that do not express this gene. Re-expression of ADAMTS9 was observed after demethylation drug treatment, confirming that hypermethylation is involved in gene downregulation. Downregulation of ADAMTS9 was also found in 43.5 and 47.6% of primary esophageal tumor tissues from Hong Kong and from the high-risk region of Henan, respectively. Thus, this study identifies and provides functional evidence for a CR associated with tumor suppression on 3p14.2 and provides the first evidence that ADAMTS9, mapping to this region, may contribute to esophageal cancer development.