Congenital esophageal stenosis associated with esophageal atresia: new concepts

Congenital esophageal stenosis (CES) is suspected by a fixed intrinsic narrowing of the esophagus that affects the normal swallowing mechanism. The diagnosis is only confirmed by histopathologic picture, which may show fibromuscular disease (FMD) or tracheobronchial remnants (TBR). The latter involves ciliated pseudo stratified columnar epithelium, seromucous glands or cartilage each alone or in combination. The aim of this study is to document the usefulness of histologic picture of surgical specimens obtained from the lower esophageal pouch (LEP) during primary repair in detecting cases of CES associated with esophageal atresia (EA) with or without tracheoesophageal fistula (TEF). Over an 8-year period, 57 consecutive cases operated upon for EA with or without TEF were subjected for histologic examination of surgical specimens obtained from the tip of the LEP. Cases that histologically showed FMD or TBR were included. The usefulness of this histologic picture as a diagnostic and therapeutic aid is assessed. Methods of treatment and outcome were also reviewed. Eight patients out of 57 (14%) had a histologic picture suggestive of CES, two with FMD, four with TBR without cartilage and two with cartilage. Out of 57 patients, 23 developed strictures, six of them had positive biopsies suggestive of CES. One patient with TBR without cartilage did not have stricture. Another case of pure atresia had LEP resection and gastric pull up showed cartilage involving the whole lower esophagus. Excluding the case of pure EA with gastric pull up, all patients suffered from feeding problems and recurrent aspiration. Fluoroscopic barium studies showed late onset minor dysmotility in five patients and late onset major dysmotility in two. All cases studied showed significant gastro-esophageal reflux (GER). Stricture was seen at the anastomotic site extending distally in the two fibromuscular cases and one case with cartilage, at the anastomotic site in three cases with TBR without cartilage. Anti reflux surgical procedures were performed in four patients without benefit in two patients with major dysmotility. Dilatation was successful in the three patients with TBR without cartilage. One patient with cartilage had resection of the anastomotic site and required frequent dilatations and is now doing well. A case of FMD did not improve after frequent dilatations and myotomy together with Nissen’s fundoplication and required resection while the other case of FMD responded partially to dilatations. Cartilage in cases of CES requires surgical resection. Those with TBR without cartilage may not develop stricture. If stricture develops, it responds well to dilatation and patients have good clinical outcomes. Unlike isolated CES, GER is a significant feature in CES with EA. Anti reflux procedures should be avoided before definitive surgery for the stricture and if necessary a partial wrap with gastrostomy is recommended. CES should be considered in the etiology of anastomotic stricture. Taking a surgical specimen routinely from the tip of the LEP during primary esophageal repair for histologic studies is highly recommended.     

Characterization of polymeric poly(epsilon-caprolactone) injectable implant delivery system for the controlled delivery of contraceptive steroids

Contraceptive steroids levonorgestrel (LNG) and ethinyl estradiol (EE) have been encapsulated with poly(epsilon-caprolactone) (PCL) microspheres using a w / o /w double emulsion method. The microspheres prepared were smooth and spherical, with a mean size from 8-25 microm. In vitro release profiles of microspheres showed a trend of increasing initially at the first week, and thereafter the release was sustained. At the end of the seventh week LNG/EE from 1:5 and 1:10 PCL microspheres were 60 and 48%, 52 and 46%, respectively. An in vitro degradation study shows that at the 20th week the microspheres maintained the surface integrity. The PCL microspheres showed a triphasic in vivo release profile with an initial burst effect due to the release of the steroid adsorbed on the microsphere surface, a second sustained release phase due to the steroid diffusion through the pores or channels formed in the polymer matrix, and third phase due to polymer bioerodible. Histological examination of PCL microspheres injected intramuscularly into thigh muscle of a rat showed a minimal inflammatory reaction demonstrating that contraceptive steroid-loaded microspheres were biocompatible. The level of inflammatory cytokines determined by immunostaining for IL-1alpha, the tissue response to formulations at the first week was considered mild, whereas at the end of the 20th week the inflammatory response ceased. Thus, this study helped us to evaluate the feasibility of using these microspheres as a long-acting biodegradable drug delivery system for contraceptive steroids.     

Modulation of cell cycle progression by CTLA4-CD80/CD86 interactions on CD4+ T cells depends on strength of the CD3 signal: critical role for IL-2

Cytotoxic T-lymphocyte antigen 4 (CTLA4) is a well-studied T cell costimulatory receptor that is known to inhibit T cell activation. In this study, the relationship between strength of the first signal and costimulatory interactions on primary mouse CD4(+) T cells was investigated. CTLA4-CD80/CD86 interactions differentially modulate T cell cycling based on the mode of CD3 signal: Activation with plate-bound (pb) anti-CD3 generates a strong signal compared with a weak signal with soluble (sol) anti-CD3, resulting in approximately sevenfold higher amounts of interleukin (IL)-2 and an increase in cell cycling. Activation of T cells with sol anti-CD3 (weak signal) together with CTLA4-CD80/CD86 blockade lowers IL-2 production and cell cycling, demonstrating an enhancing role for these interactions. Conversely, blockade of CTLA4-CD80/CD86 interactions on T cells activated with pb anti-CD3 (strong signal) increases proliferation, which is consistent with CTLA4 as a negative regulator. Also, coculture of T cells with Chinese hamster ovary cells expressing CD80 or CD86 demonstrates that the strength of the primary signal plays an important role. It is important that modulation of IL-2 amounts leads to distinct alterations in the functional effects of CTLA4-CD80/CD86 interactions. On increasing IL-2 amounts, activation of T cells stimulated with sol anti-CD3 (weak signal) and CTLA4-CD80/CD86 blockade is greater compared with control. Concurrently, neutralization of IL-2 greatly reduces activation of T cells stimulated with pb anti-CD3 (strong signal) and CTLA4-CD80/CD86 blockade compared with control. These results underscore the importance of strength of first signal, CTLA4-CD80/CD86 interactions, and IL-2 amounts in modulating primary CD4(+) T cell responses.     

Is it a safe practice to administer oxygen during uncomplicated delivery: A randomized controlled trial?

Background

Newborns exposed to oxygen suffer from an oxidative stress with significant alterations in the concentrations of superoxide dismutase (SOD) and glutathione (GSSG).

Objective

To investigate the biological and clinical effects of oxygen administration to delivering mothers.

Methods

We conducted a randomized, double-blinded, controlled trial on a cohort of delivering women (n = 56) with an uncomplicated term pregnancy. Women were randomly assigned to one of two groups: Oxygen group or Room Air group. The Oxygen group received 100% oxygen (2 l/min) via nasal cannula for at least 30 min before delivery. Subjects in the Room Air group were connected to a nasal cannula while on room air. Concentrations of SOD (μg/g of Hb) and GSSG (μM/ml) were measured in maternal and umbilical cord blood. Bivariate and multivariate analyses were used to compare the two groups using the SAS system.

Results

Maternal SOD and GSSG did not differ between the two groups at baseline or after delivery. Concentrations of SOD and GSSG in umbilical cord blood did not differ between groups. More infants in Oxygen Group required delivery room resuscitation (20% vs. 0%, P = 0.03). This difference could not be explained by mode of delivery, infant sex, or other confounders.

Conclusions

Maternal exposure to oxygen during delivery is not associated with changes in umbilical cord SOD or GSSG. Further studies are needed to explore mechanisms responsible for the need of resuscitation in the oxygen group.     

Extrinsic versus intrinsic cues in avian paraxial mesoderm patterning and differentiation.

Somitic and head mesoderm contribute to cartilage and bone and deliver the entire skeletal musculature. Studies on avian somite patterning and cell differentiation led to the view that these processes depend solely on cues from surrounding tissues. However, evidence is accumulating that some developmental decisions depend on information within the somitic tissue itself. Moreover, recent studies established that head and somitic mesoderm, though delivering the same tissue types, are set up to follow their own, distinct developmental programmes. With a particular focus on the chicken embryo, we review the current understanding of how extrinsic signalling, operating in a framework of intrinsically regulated constraints, controls paraxial mesoderm patterning and cell differentiation.     

Improved Identification of Epidemiologically Related Strains of Salmonella enterica by use of a Fusion Algorithm Based on Pulsed-Field Gel Electrophoresis and Multiple-Locus Variable-Number Tandem-Repeat Analysis

Pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem-repeat analysis (MLVA) are used to assess genetic similarity between bacterial strains. There are cases, however, when neither of these methods quantifies genetic variation at a level of resolution that is well suited for studying the molecular epidemiology of bacterial pathogens. To improve estimates based on these methods, we propose a fusion algorithm that combines the information obtained from both PFGE and MLVA assays to assess epidemiological relationships. This involves generating distance matrices for PFGE data (Dice coefficients) and MLVA data (single-step stepwise-mutation model) and modifying the relative distances using the two different data types. We applied the algorithm to a set of Salmonella enterica serovar Typhimurium isolates collected from a wide range of sampling dates, locations, and host species. All three classification methods (PFGE only, MLVA only, and fusion) produced a similar pattern of clustering relative to groupings of common phage types, with the fusion results being slightly better. We then examined a group of serovar Newport isolates collected over a limited geographic and temporal scale and showed that the fusion of PFGE and MLVA data produced the best discrimination of isolates relative to a collection site (farm). Our analysis shows that the fusion of PFGE and MLVA data provides an improved ability to discriminate epidemiologically related isolates but provides only minor improvement in the discrimination of less related isolates.Salmonellosis is one of the most common food-borne diseases in the United States (5). Consequently, it is important to understand how Salmonella strains disseminate within and between reservoirs and environments. Many molecular typing tools have been used for this purpose (11). Of these methods, pulsed-field gel electrophoresis (PFGE) is considered by many to be the gold standard for strain typing, and variable-number tandem-repeat (VNTR) assays are powerful alternative or complementary typing tools (3, 22). Both methods offer a high degree of genetic resolution for strain typing, depending on several factors.PFGE involves separating chromosomal DNA macro-restriction fragments by size, and strains are discriminated based on the resulting band pattern observed after electrophoresis has been completed. It is one of the most reproducible and highly discriminatory typing techniques and has been widely and successfully used for a variety of Salmonella enterica serovars (12, 15); for many situations, PFGE is capable of discriminating between closely related strains. In addition, the use of the assay to analyze different serovars does not require a great deal of modification, as might be required with procedures that are dependent on PCR. Difficulties arise when strains are very closely related (i.e., poor discrimination [18, 27]) or when bands comigrate in the gel or identically sized bands represent completely different fragments of chromosomal DNA and thereby produce spurious matches (6). These complications are more pronounced when a large number of bands are generated by the restriction digest (4). In addition, while band patterns convey a crude degree of genetic relatedness, a large number of independent restriction digests would be needed to infer an accurate phylogenetic relationship (6).Multiple-locus variable-number tandem-repeat analysis (MLVA) is a PCR-based technique that relies on the amplification of chromosomal or plasmid DNA that encompasses short tandem repeats of a DNA sequence. The tandem repeats are prone to higher-than-background mutation rates due to DNA strand slippage during replication (23), and thus, the amplified fragments will vary in length depending on the number of repeats harbored at a given locus. Different fragment lengths are tallied either as the total length (base pairs) or the estimated number of repeat units, and each discretely sized fragment is considered a unique “allele” for the locus under investigation. Because of the relatively high mutation rate, strains can accumulate distinctive allele patterns within a relatively short period of time (5). Furthermore, the technique can be multiplexed and automated and is conducive to rapid and relatively high-throughput strain typing. MLVA assays are relatively robust (5, 15-17) and, while not perfect, they can provide phylogenetic information even with a limited number of loci (13, 18). While access to a sequenced genome dramatically speeds the ability to establish new assays (3), it is not a requisite to assay development. The primary limitations of the technique include the potential need for a new set of loci for every species or serovar under investigation and the fact that some loci are very “unstable” and can “disappear” from some strains or lineages; this produces the equivalent of an uninformative “null” allele. Mutation rates can also vary between loci (5, 24, 25); if ignored, this factor can introduce bias into comparative analyses.Clearly, PFGE and MLVA offer different technical and interpretive advantages and disadvantages, but it is important to emphasize that the nature of the methodological and interpretive errors is independent between the techniques. For example, errors due to comigration of bands for PFGE are independent of band size estimation errors for MLVA because differences in MLVA band size are not detectable using PFGE and macro-restriction fragments are generally independent of tandem-repeat sequences. Provided that most of the experimental variation from these two methods is uncorrelated (i.e., independent), it is possible to combine results from the two methods to produce improved estimates (8), and this premise underlies the current study.Our objective was to determine whether combining the information obtained from both PFGE and MLVA assays produces more rigorous and discriminatory analyses of bacterial pathogens, such as Salmonella. Two sets of Salmonella enterica isolates were used in this study; one set included serovar Typhimurium isolates from a wide range of sampling dates, locations, and host species while the other set included a group of serovar Newport isolates collected over a limited geographic and temporal scale for a single host species. The results of the different typing methods were assessed by comparison with those of phage-typing assays (serovar Typhimurium) and with known epidemiological relationships (serovar Newport). To interpret the MLVA data, we employed a metric that incorporates a stepwise-mutation model, and to interpret the PFGE data, we employed Dice coefficients to construct distance matrices. Our analysis shows that the fusion of the two typing methods provides an improved ability to discriminate between isolates when PFGE and MLVA separately provide partial but incomplete discrimination between strains with a high degree of probable genetic similarity.     

Screening for coeliac disease among Egyptian children

Introduction

To screen for coeliac disease in Egyptian children with non-endocrinal short stature, refractory iron deficiency anaemia and type 1 diabetes. Also, to evaluate the sensitivity and specificity of different serological tests for diagnosis of coeliac disease (CD).

Material and methods

The study included 292 patients with clinical risk of CD. Testing for coeliac antibodies was performed, together with upper gastrointestinal endoscopy and small intestinal biopsy.

Results

Eleven patients (44%) among 25 patients with refractory iron deficiency anaemia, 23 patients (34.3%) among 67 patients with non-endocrinal short stature, and 6 patients (3%) among 200 patients with type I diabetes mellitus were diagnosed by jejunal biopsy as having coeliac disease. AGA (IgG) had the highest sensitivity for diagnosing CD (80.0%) followed by the TTG (72.7%) antibody, while ARA had the highest specificity (95.9%) followed by anti-EMA (94.7%).

Conclusions

Coeliac disease is more common in Egyptian children with refractory iron deficiency anaemia, non-endocrinal short stature and type 1 diabetes than was previously thought; therefore it is mandatory to screen such patients for CD. Serological tests showed fairly good sensitivity and specificity for the diagnosis; however, intestinal biopsy remains the cornerstone for definitive diagnosis of patients with immunological reaction to gluten.     

Potential Influence of Interleukin-1 Receptor Antagonist Gene Polymorphism on Knee Osteoarthritis Risk

Objectives: Genes encoding for cytokines have been associated with susceptibility for joint osteoarthritis (OA) and interleukin (IL)-1 gene is supposed to be involved in the cartilage destruction process. In this regard, interleukin-1 receptor antagonist (IL-1RA) competing with IL-1 for binding to its receptor may act as an inhibitor of cartilage breakdown. We assessed the association of primary knee OA with IL-1RA region as a putative factor of susceptibility to knee OA in Egyptian patients. Design and methods: Eighty patients with primary knee OA and 40 aged-matched healthy controls were included into the study. DNA samples were used to study genotypes of IL-1RN gene by polymerase chain reaction (PCR) in both groups. Results: An increased frequency of the IL-1RN*1 and IL-1RN*2 alleles was found in OA patients relative to controls (60.5% vs. 39.5%, P = 0.039, 85.4% vs. 14.6%, P = 0.002, respectively) however, only the carriage rate of IL-1RN*2 allele was found to be significant when OA patients were compared to the controls. Significant higher frequencies of IL-1RN*1/*2 and IL-1RN*2/*2 genotypes in OA patients were observed as compared with controls. Both visual analogue scale (VAS) and radiographic score revealed significant correlation with both the allelic frequency and the carriage rate of IL-1RN*2 allele. Moreover, absolute frequency of IL-1RN*1/*2 genotype OA patients revealed severe VAS and high radiographic score. Conclusion: These results suggest that IL-1RN*2 allele represent a significant factor influencing the severity and course of knee OA; thereby supporting the potential role of IL-1 in the pathogenesis of this disease.