Transcription factor dynamics, oscillation, and functions in human enteroendocrine cell differentiation.

Enteroendocrine cells (EECs), which secrete serotonin (enterochromaffin cells, EC) or a dominant peptide hormone, serve vital physiologic functions. As with any adult human lineage, the basis for terminal cell diversity remains obscure. We replicated human EEC differentiation in vitro , mapped transcriptional and chromatin dynamics that culminate in discrete cell types, and studied abundant EEC precursors expressing selected transcription factors (TFs) and gene programs. Before expressing the pre-terminal factor NEUROD1, non-replicating precursors oscillated between epigenetically similar but transcriptionally distinct ASCL1 + and HES6 hi cell states. Loss of either factor substantially accelerated EEC differentiation and disrupted EEC individuality; ASCL1 or NEUROD1 deficiency had opposing consequences on EC and hormone-producing cell features. Expressed late in EEC differentiation, the latter TFs mainly bind cis -elements that are accessible in undifferentiated stem cells and tailor the subsequent expression of TF combinations that specify EEC types. Thus, TF oscillations retard EEC maturation to enable accurate EEC diversification.

Institutional arthroplasty registry: what is the minimum acceptable dataset to be included in your hospital? Recommendations from a single-country national consensus using the Delphi method.

PURPOSE: Institutional arthroplasty registries are very popular nowadays; however, very few efforts have been made in order to standardize the information to be collected, thus limiting the possibility of inter-institutional data interpretation. This manuscript reports the results of a single-country consensus designed to define the minimum standardized dataset to be recorded within an institutional arthroplasty registry. METHODS: A national consensus was carried out among all members of the Colombian Society of Hip and Knee Surgeons using the Delphi method. Eleven questions and answers comprising every potential domain of an institutional registry of hip and knee arthroplasty were defined. According to the methodology, anonymous voting and multiple discussion rounds were performed. Three levels of agreement were defined: Strong consensus: equal to or greater than 80%, weak consensus between 70 and 79.9%, and no consensus below 70%. RESULTS: All of the questions reached consensus level. The minimum dataset was defined to include demographic and clinical information, intraoperative and implant details, follow-up and early complications, implant survival, and functional outcome scores, as well as the validation model to assess information quality within the database. Currently, this dataset is being implemented voluntarily by the members of our national society. DISCUSSION: A national consensus is a feasible method to build homogeneous arthroplasty registries. We recommend such an exercise since it establishes the basis to compare and add data between institutions and the joint analysis of said information in a national registry.

Surgical site infection and transfusion rates are higher in underweight total knee arthroplasty patients.

BACKGROUND: Underweight (UW) patients undergoing total hip arthroplasty have exhibited higher complication rates, including infection and transfusion. No study to our knowledge has evaluated UW total knee arthroplasty (TKA) patients. We, therefore, conducted a study to investigate if these patients are at increased risk for complications, including infection and transfusion. METHODS: A case-control study was conducted using a prospectively collected institutional database. Twenty-seven TKA patients were identified as UW (body mass index [BMI] < 18.5 kg/m2) from 2000-2012 and were matched for age, gender, date of surgery, age-adjusted Charlson comorbidity index, rheumatoid arthritis, and diabetes. These patients were compared to 81 normal weight patients (BMI 18.5-24 kg/m2). Demographic variables were compared, along with wound complications, surgical site infection (SSI), blistering, deep vein thrombosis, pulmonary embolism, transfusion, revision, flexion contracture, hematoma formation, and patellar clunk. RESULTS: The average BMI was 17.1 kg/m2 (range 12.8-18.4) for UW and 23.0 kg/m2 (range 19.0-25.0) for normal weight patients (P < .001). UW TKA patients were more likely to develop SSIs (3/27, 11.1% vs 0/81, 0.0%, P = .01) and were more likely to require transfusions (odds ratio = 3.4, confidence interval 1.3-9.1; P = .02). CONCLUSIONS: Our study demonstrates that UW TKA patients have a higher likelihood of developing SSI and requiring blood transfusions. The specific reasons are unclear, but we conjecture that it may be related to decreased wound healing capabilities and low preoperative hemoglobin. Investigation of local tissue coverage and hematologic status may be beneficial in this patient population to prevent SSI. Based on the results of this study, a prospective evaluation of these factors should be undertaken.

Should Preoperative Antibiotics Be Tailored According to Patient's Comorbidities and Susceptibility to Organisms?

BACKGROUND: Preoperative antibiotic prophylaxis remains one of the most important strategies for preventing periprosthetic joint infection (PJI). Current guidelines recommend giving universal antibiotic prophylaxis to all total joint arthroplasty patients regardless of their medical conditions or immune status; however, no studies have evaluated the individualizing of antibiotics. The aims of this study were (1) to determine if comorbidities influence the organism profile of PJIs, and (2) to investigate if the efficacy of two different perioperative antibiotics (cefazolin or vancomycin) for preventing PJI is affected by patient's comorbidities. METHODS: Using an institutional database of 1022 PJIs, the influence of different patient's comorbidities on the organism profile was evaluated. To investigate the influence of perioperative antibiotics (cefazolin or vancomycin monotherapy) on PJI rate, 8575 primary total joint arthroplasties were identified, crossmatched for PJI, and analyzed based on the comorbidities of the cohort. The PJI rate of each antibiotic within each comorbidity was compared. RESULTS: Although no comorbidities were associated with an increased rate of Gram-positive infections or Gram-negative infections, metastatic disease (odds ratio [OR] 5.71, P = .018), congestive heart failure (OR 2.2, P = .010), chronic pulmonary disease (OR 1.76, P = .015), and diabetes mellitus (OR 1.66, P = .019) were associated with antibiotic resistant organisms. However, there was no difference in the PJI rate between cefazolin and vancomycin monotherapy when stratifying for diabetes mellitus, rheumatoid arthritis, liver disease, and hypothyroidism. CONCLUSION: The results of the present study support the current recommendations of a universal antibiotic prophylaxis protocol rather than an antibiotic regimen individualized to a patient's comorbidities.

Patients With Failed Prior Two-Stage Exchange Have Poor Outcomes After Further Surgical Intervention.

BACKGROUND: Failure of 2-stage exchange arthroplasty for the management of periprosthetic joint infection (PJI) poses a major clinical challenge. There is a paucity of information regarding the outcomes of further surgical intervention in these patients. Thus, we aim to report the clinical outcomes of subsequent surgery for a failed prior 2-stage exchange arthroplasty. METHODS: Our institutional database was used to identify 60 patients (42 knees and 18 hips), with a failed prior 2-stage exchange, who underwent further surgical intervention between 1998 and 2012, and had a minimum 2-year follow-up. A retrospective review was performed to extract relevant clinical information, including mortality, microbiology, and subsequent surgeries. Musculoskeletal Infection Society criteria were used to define PJI, and treatment success was defined using Delphi criteria. RESULTS: Irrigation and debridement (I&D) was performed after a failed 2-stage exchange in 61.7% of patients; 56.8% subsequently failed. Forty patients underwent an intended second 2-stage exchange; 6 cases required a spacer exchange. Reimplantation occurred only in 65% of cases, and 61.6% had infection controlled. The 14 cases that were not reimplanted resulted in 6 retained spacers, 5 amputations, 2 PJI-related mortalities, and 1 arthrodesis. CONCLUSION: Further surgical intervention after a failed prior 2-stage exchange arthroplasty has poor outcomes. Although I&D has a high failure rate, many patients who are deemed candidates for a second 2-stage exchange either do not undergo reimplantation or fail after reimplantation. The management of PJI clearly remains imperfect, and there is a dire need for further innovations that may improve the care of these patients.

Positive Culture During Reimplantation Increases the Risk of Subsequent Failure in Two-Stage Exchange Arthroplasty.

BACKGROUND: It is strongly recommended that tissue and synovial fluid culture samples be obtained during reimplantation performed as part of a 2-stage exchange arthroplasty. The rate of positive cultures during reimplantation and the influence of positive cultures on subsequent outcomes, to our knowledge, are unknown. This study was designed to determine the rate of positive cultures during reimplantation and to investigate the association between positive cultures at reimplantation and subsequent outcomes. METHODS: We retrospectively reviewed the data of 259 patients who met the Musculoskeletal Infection Society criteria for periprosthetic joint infection (PJI) and who underwent both stages of 2-stage exchange arthroplasty at our institution from 1999 to 2013. Among these patients were 267 PJIs (186 knees and 81 hips); 33 (12.4%) had ≥1 positive culture result at reimplantation. Treatment failure was assessed according to the Delphi-based consensus definition. Logistic regression analysis was performed to assess the predictors of positive culture and risk factors for failure of 2-stage exchange arthroplasty. RESULTS: Of the 33 cases with PJI, 15 (45.5%) had a subsequent failure of the 2-stage exchange arthroplasty compared with 49 (20.9%) of the cases that were culture-negative at reimplantation. When controlling for other variables using multivariate analyses, the risk of treatment failure was higher (odds ratio = 2.53; 95% confidence interval [CI] = 1.13 to 5.64) and reinfection occurred earlier (hazard ratio = 2.00; 95% CI = 1.05 to 3.82) for the cases with a positive culture during reimplantation. The treatment failure rate did not differ (p = 0.73) between cases with ≥2 positive cultures (36.4%) and 1 positive culture (50%). CONCLUSIONS: Positive intraoperative culture at the time of reimplantation, regardless of the number of positive samples, was independently associated with >2 times the risk of subsequent treatment failure and earlier reinfection. Surgeons should be aware that a positive culture at the time of reimplantation independently increases the risk of subsequent failure. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Fate of Spacers in the Treatment of Periprosthetic Joint Infection.

BACKGROUND: Two-stage exchange arthroplasty remains the preferred method to treat periprosthetic joint infection. The aim of this study was to investigate the clinical course of periprosthetic joint infection following resection arthroplasty and insertion of a spacer. METHODS: Our institutional database was used to identify 504 cases of periprosthetic joint infection (326 knees and 178 hips) treated with resection arthroplasty and spacer insertion as part of a two-stage exchange arthroplasty. A review of the patient charts was performed to extract information relevant to the objectives of this study that included the details of the clinical course following resection arthroplasty. RESULTS: The mean follow-up duration after initial spacer implantation was 56.2 months. Reimplantation occurred in the joints of 417 (82.7%) of 504 cases. Of these 417 cases, 329 (78.9%) had a minimum one-year follow-up, and 81.4% of these had successful treatment. The mean duration from resection arthroplasty to reimplantation was 4.2 months (range, 0.7 to 131.7 months). Sixty (11.9%) of the 504 joints required interim spacer exchange(s). Of the eighty-seven cases that did not undergo reimplantation, six (6.9%) required amputation, five (5.7%) underwent a Girdlestone procedure, four (4.6%) underwent arthrodesis, and seventy-two (82.8%) underwent spacer retention. Thirty-six patients died in the interstage period. CONCLUSIONS: The commonly held belief that two-stage exchange arthroplasty carries a high success rate for the eradication of periprosthetic joint infection may need to be reexamined. A considerable number of patients undergoing the first stage of a two-stage procedure do not undergo a subsequent reimplantation for a variety of reasons or require an additional spacer exchange in the interim. Reports on the success of two-stage exchange should account for the mortality of these patients and for patients who never undergo reimplantation.

Reliability, Readability and Quality of Online Information about Femoracetabular Impingement.

BACKGROUND: The Internet has become the most widely-used source for patients seeking information more about their health and many sites geared towards this audience have gained widespread use in recent years. Additionally, many healthcare institutions publish their own patient-education web sites with information regarding common conditions. Little is known about how these resources impact patient health, though, as they have the potential both to inform and to misinform patients regarding their prognosis and possible treatments. In this study we investigated the reliability, readability and quality of information about femoracetabular impingement, a condition which commonly affects young patients. METHODS: The terms "hip impingement" and "femoracetabular impingement" were searched in Google® in November 2013 and the first 30 results were analyzed. The LIDA scale was used to assess website accessibility, usability and reliability. The DISCERN scale was used to assess reliability and quality of information. The FRE score was used to assess readability. RESULTS: The patient-oriented sites performed significantly worse in LIDA reliability, and DISCERN reliability. However, the FRE score was significantly higher in patient-oriented sites. CONCLUSION: According to our results, the websites intended to attract patients searching for information regarding femoroacetabular impingement are providing a highly accessible, readable information source, but do not appear to apply a comparable amount of rigor to scientific literature or healthcare practitioner websites in regard to matters such as citing sources for information, supplying methodology and including a publication date. This indicates that while these resources are easily accessed by patients, there is potential for them to be a source of misinformation.

Preoperative anemia increases postoperative complications and mortality following total joint arthroplasty.

Single-institution, large case-controlled study examines the association between preoperative anemia and adverse outcomes following total joint arthroplasty (TJA). We collected data from our institutional database of patients who underwent primary and aseptic revision TJA. Only 2576 patients had anemia preoperatively, and 10,987 patients had hemoglobin within the normal range. Multivariate analysis was used to determine the effect of preoperative anemia on the incidence of medical complications, infection, LOS and mortality. Anemic patients had a higher rate of complications (odds ratio 2.11), namely cardiovascular 26.5% versus 11.8%, and genitourinary 3.9% versus 0.9%. Our study confirms that patients with preoperative anemia are likely to exhibit a higher incidence of postoperative complications following TJA. Preoperative optimization may be needed in an effort to reduce these complications.

Stiffness after total knee arthroplasty.

Stiffness after total knee arthroplasty (TKA) adversely affects outcome and impacts patient function. Various risk factors for stiffness after TKA have been identified, including reduced preoperative knee range of motion, history of prior knee surgery, etiology of arthritis, incorrect positioning or oversizing of components, and incorrect gap balancing. Mechanical and associated causes, such as infection, arthrofibrosis, complex regional pain syndrome, and heterotopic ossification, secondary gain issues have also been identified. Management of stiffness following TKA can be challenging. The condition needs to be assessed and treated in a staged manner. A nonsurgical approach is the first step. Manipulation under anesthesia may be considered within the first 3 months after the index TKA, if physical therapy fails to improve the range of motion. Beyond this point, consideration should be given to surgical intervention such as lysis of adhesions, either arthroscopically or by open arthrotomy. If the cause of stiffness is deemed to be surgical error, such as component malpositioning, revision arthroplasty is indicated. The purpose of this article is to evaluate the various aspects of management of stiffness after TKA.

Evaluation of two serological methods for potency testing of whole cell pertussis vaccines.

The European Pharmacopoeia (Ph. Eur.) and the World Health Organization (WHO) require the performance of extensive quality control testing including a potency test before a vaccine batch is released for human use. Whole cell pertussis (wP) vaccine potency is assessed by a mouse protection test (MPT) based on the Kendrick test. This test compares the vaccine dose necessary to protect 50% of mice against the effect of a lethal intracerebral dose of Bordetella pertussis and the dose of a suitable reference vaccine needed to give the same protection level. Due to the large variability in the results of this test and the severe distress which is inflicted on the many animals involved, its replacement by an alternative method is highly desirable. At the initiative of the European Directorate for the Quality of Medicines and HealthCare (EDQM) of the Council of Europe, in collaboration with the WHO and the In-vitro toxicology Unit/European Centre for the Validation of Alternative Methods (ECVAM) of the European Commission (EC) Joint Research Centre-Institute for Health and Consumer Protection (JRC-IHCP), wP vaccine specialists from all over the world were invited to present an overview of candidate alternatives at a symposium organised in Geneva (Switzerland) in March 2005. Although no alternative method was found suitable for immediate implementation of batch potency control, the Pertussis Serological Potency Test (PSPT), initially developed in mice and recently transferred to guinea pigs (gps), was identified as a model of interest. Using the PSPT in gps to test several components of combined vaccines such as Diphtheria-Tetanus-wP vaccines in the same animal series would allow further implementation of the European 3Rs policy to batch potency control, by additional method refinement and reduction of animal use. The present study evaluated 2 features of the serological response to wP vaccination: 1) the overall antibody response as measured by a "whole cell" ELISA (PSPT-wC-ELISA) which uses the B. pertussis 18323 challenge strain prescribed for the MPT to coat the assay plates and 2) the functional neutralising antibodies to pertussis toxin (PT, one of the main virulence factors of B. pertussis), as measured by the Chinese Hamster Ovary (CHO) cell assay. The results showed that 1) the gp model can be used for wP vaccine potency testing; 2) despite good repeatability and precision, the CHO cell assay did not generate results comparable to the MPT. Moreover, the CHO cell assay showed significant differences in the ability of wP vaccines to induce neutralising anti-PT antibodies, which did not correlate to the overall antibody response evaluated by PSPT-wC-ELISA; 3) comparable potencies were obtained in the MPT and the PSPT-wC-ELISA. This study, supported by the previous ones correlating the PSPT-wC-ELISA in mice with the MPT, confirms that PSPT-wC-ELISA in gps is a promising approach for batch release potency testing of wP vaccines for which consistency in production has already been demonstrated by the MPT. However, a large scale validation study is required prior to the adoption of PSPT-wC-ELISA as a compendial reference method for wP vaccines batch release control.

Interleukin-1 gene polymorphisms and gastric cancer risk in a high-risk Italian population.

OBJECTIVES: Host genetic factors, including the IL1 gene cluster, play a key role in determining the long-term outcome of Helicobacter pylori infection. The aim of the study was to investigate the relationship between selected IL1 loci polymorphisms and gastric cancer risk in an Italian population. METHODS: In a case-control study we compared the IL1B-31 and IL1B+3954 biallelic and IL1RN pentaallelic variable number of tandem repeats (VNTR) polymorphisms in 185 gastric cancer patients and 546 controls randomly sampled from the general population of an area at high gastric cancer risk (Tuscany, Central Italy). RESULTS: Genotype frequencies of the IL1B-31 T/C, IL1B+3954 C/T, and IL1RN polymorphisms among our population controls were in Hardy-Weinberg equilibrium. In multivariate analyses, no increase in gastric cancer risk was observed for the IL1B-31*C- and IL1B+3954*T- carriers; a significant 50% increase emerged for IL1RN*2 allele carriers (OR = 1.49; 95% CI: 1.01-2.21). Analyses based on combined genotypes showed also that the association with IL1RN*2 allele was limited to two-variant allele carriers who were also homozygous for the IL1B-31*T allele (OR = 2.23; 95% CI: 1.18-4.23) with a statistically significant interaction between these two genotypes (p= 0.043). Haplotype analysis showed an increased risk for the haplotype IL1RN*2/IL1B-31*T. CONCLUSIONS: Our results suggest that host genetic factors (such as the IL1RN and the IL1B-31 polymorphisms) interact in the complex process of gastric carcinogenesis in this high-risk Italian population. Overall, this effect appears more modest than previously reported in other populations, supporting the hypothesis that other still-to-be-defined factors are important in gastric carcinogenesis. These findings might be due to a haplotype effect.

Serological response to the outer membrane lipoprotein in animal brucellosis.

The presence of antibodies to Brucella outer membrane lipoprotein was investigated in cattle and rams. Low but significant amounts of antibody were detected in sera from B. abortus-infected cattle and from B. ovis-infected rams which had developed epididymitis. Strain-19-vaccinated cattle also showed a weak albeit transient antibody response.

Brucella outer membrane lipoprotein shares antigenic determinants with Escherichia coli Braun lipoprotein and is exposed on the cell surface.

In an enzyme-linked immunosorbent assay (ELISA), purified Brucella abortus and Escherichia coli peptidoglycan-linked lipoproteins gave a strong cross-reaction with sera from rabbits hyperimmunized with the heterologous lipoprotein. When smooth E. coli cells were used as ELISA antigens, the immunological cross-reaction was not observed unless the cells were treated to remove lipopolysaccharide and other outer membrane components. In contrast, intact cells from smooth strains of B. abortus and Brucella melitensis bound anti-lipoprotein immunoglobulin G, and the controls performed by ELISA showed that this reaction was not due to antibodies to the lipopolysaccharide, group 3 outer membrane proteins, or porins. Electron microscopy of cells labeled with antilipoprotein serum and protein A-colloidal gold showed specific labeling of smooth cells from both B. abortus and B. melitensis, even though unspecific labeling by nonimmune serum was observed with rough B. abortus. These results confirm the close similarity between E. coli and Brucella peptidoglycan-linked lipoproteins and show that, in contrast to E. coli, the lipoprotein of B. abortus and B. melitensis is partially exposed on the surface of smooth cells.

Demonstration of a peptidoglycan-linked lipoprotein and characterization of its trypsin fragment in the outer membrane of Brucella spp.

The sodium dodecyl sulfate (SDS) extraction-trypsin digestion protocol used by Braun and Sieglin (V. Braun and U. Sieglin, Eur. J. Biochem. 13:336-346, 1970) to show the peptidoglycan-linked lipoprotein of Escherichia coli was applied to both Brucella abortus and E. coli. Whereas a single polypeptide of 8,000 molecular weight was obtained from E. coli, several proteins of apparent molecular weight lower than 35,000 were demonstrated by SDS-polyacrylamide gel electrophoresis in B. abortus. These results did not change when the trypsin digestion conditions were modified. On the other hand, when the SDS extractions were performed under conditions more stringent than those used for other gram-negative bacteria, only a polypeptide fragment of apparent molecular weight of 8,000 was obtained from B. abortus. This polypeptide was similar to the trypsin fragment of the E. coli lipoprotein with respect to its behavior in SDS-polyacrylamide gels, isoelectric point in urea, molecular weight, and presence of both ester- and amide-linked fatty acids. Moreover, the amino acid analysis showed an overall similarity with respect to the amino acid composition of E. coli lipoprotein. A polypeptide of the same molecular weight, isoelectric point, and amino acid composition was also obtained from Brucella ovis by the same method. These results demonstrated that B. abortus and B. ovis cell envelopes contain a lipoprotein and strongly support the hypothesis that it is the only major protein covalently linked to the peptidoglycan.