Support of human cord blood progenitor cells on human stromal cell lines transformed by SV40 large T antigen under the influence of an inducible (metallothionein) promoter

We describe the development of a human bone marrow (BM) culture system which allows study of the interaction of stromal cell lines (SCL) and highly purified hematopoietic progenitor cells. Normal BM stromal cells were electroporated with a plasmid containing the simian virus 40 (SV40) large T antigen (SV40 T Ag) under the control of a synthetic metallothionein promoter (MT4); this construct is designated MT4 SV40 T Ag. SCL in which the rate of proliferation could be controlled by altering the zinc (Zn) concentration were characterized, demonstrating that the SCL were heterogeneous with respect to G-CSF and GM-CSF production. Suppression of SCL proliferation on removal of Zn made it possible to use these lines in coculture with purified CD34+ progenitor cells from umbilical cord blood. The ability to control proliferation of SCL has allowed us to maintain the survival and expansion of colony- forming cells in culture for up to 2 months. These lines have enabled us to test for stromal cell characteristics at a clonal level and provided us with a tool to analyze the events leading to lineage commitment and hematopoietic differentiation, as demonstrated by suppression of hematopoiesis by an antibody directed against the c-kit molecule.     

Validity evidence for the Simulated Colonoscopy Objective Performance Evaluation scoring system

Background

Low-cost, objective systems to assess and train endoscopy skills are needed. The aim of this study was to evaluate the ability of Simulated Colonoscopy Objective Performance Evaluation to assess the skills required to perform endoscopy.

Methods

Thirty-eight subjects were included in this study, all of whom performed 4 tasks. The scoring system measured performance by calculating precision and efficiency. Data analysis assessed the relationship between colonoscopy experience and performance on each task and the overall score.

Results

Endoscopic trainees' Simulated Colonoscopy Objective Performance Evaluation scores correlated significantly with total colonoscopy experience (r = .61, P = .003) and experience in the past 12 months (r = .63, P = .002). Significant differences were seen among practicing endoscopists, nonendoscopic surgeons, and trainees (P < .0001). When the 4 tasks were analyzed, each showed significant correlation with colonoscopy experience (scope manipulation, r = .44, P = .044; tool targeting, r = .45, P = .04; loop management, r = .47, P = .032; mucosal inspection, r = .65, P = .001) and significant differences in performance between the endoscopist groups, except for mucosal inspection (scope manipulation, P < .0001; tool targeting, P = .002; loop management, P = .0008; mucosal inspection, P = .27).

Conclusions

Simulated Colonoscopy Objective Performance Evaluation objectively assesses the technical skills required to perform endoscopy and shows promise as a platform for proficiency-based skills training.     

Factors contributing to nursing home admission because of disruptive behaviour

The key relative of 417 nursing home residents was interviewed to determine reasons for admission and patient behaviour before admission using the Psychogeriatric Dependency Rating Scale (PGDRS). Families stated that 25% of new nursing home admissions were due to disruptive behaviour but there were nearly always other reasons for admission as well. A receiver operating characteristic curve and cluster analysis showed that a greater amount of generalized behaviour problems predicted admission in the 74% of new residents. Admission because of disruptive behaviour was associated with greater cognitive impairment, possible Alzheimer’s disease, delusions or hallucinations, a psychiatric diagnosis, admission from home, requiring help from others before admission and a permanent move to a nursing home. Both psychiatric and social factors are important determinants of nursing home admission for disruptive behaviour.     

Hygiene practices in abattoir and slaughter slab,determinants and assessment of abattoir and slaughter slab facilities in Abakaliki,Ebonyi State South-East Nigeria

BackgroundWorkers in slaughterhouses engaging in unhygienic practices create conducive environments for zoonoses and meat contamination. Knowledge of hygiene practices and their determinants provides evidence for the design of targeted interventions.ObjectivesWe investigated knowledge and determinants of hygiene practices among workers in slaughterhouses and assessed slaughterhouse facilities in Abakaliki.MethodsWorkers in the Central Meat Market abattoir and Slaughter slab Abakaliki were interviewed in a cross-sectional quantitative study to ascertain their knowledge and hygiene practices while abattoir facilities were assessed using a checklist. Associations were analysed with Chi-square while predictors were determined using binary logistic model.ResultsWe interviewed 188 workers 75.5% and 85.6% of whom had good knowledge and good hygiene practices respectively. However, hand-washing before and after handling meat (44.1%), cleaning work surfaces with soap and water (45.2%) and sanitary disposal of waste (6.9%) were suboptimal. Knowledge of good hygiene practice was a predictor of good hygiene practice (AOR: 4.6, 95% CI: 2.0–11.3, p=0.001). Well water and borehole were present in both slaughterhouses and cold rooms were available in Central Meat market abattoir.ConclusionsThe level of good knowledge was high and this was a determinant of good hygienic practices. Training on hygiene practices is recommended to prevent meat contamination and zoonoses.     

Epileptic Activity Intrinsically Generated in the Human Cerebellum

Neoplastic or dysplastic neuronal tissue in the brain stem and cerebellum can become epileptogenic in pediatric patients. However, it is unknown whether such tissue may transform intrinsic properties of the human cerebellum, making it capable of generating epileptic population activity. We noninvasively detected epileptiform signals unaveraged in a pediatric patient with epilepsy due to a tumor in the middle cerebellar peduncle. Analysis of generators of the signals revealed that the cerebellum ipsilateral and contralateral to the tumor was the dominant interictal spike generator and could initiate ictal activity, suggesting that human cerebellum may become capable of intrinsically generating epileptic activity. ANN NEUROL 2020;88:418–422.     

Laparoscopic ultrasound vs triphasic computed tomography for detecting liver tumors

BACKGROUND: Accurate staging of malignant tumors in the liver has major implications in defining prognosis and guiding both surgical and nonsurgical therapy. Intraoperative ultrasound in open surgery compares favorably with computed tomography (CT) in the detection of liver tumors; however, there is little experience with laparoscopic ultrasound (LUS). HYPOTHESIS: Laparoscopic ultrasound is more sensitive than triphasic CT for detecting primary and metastatic liver tumors. DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Fifty-five patients with a total of 222 lesions, including primary and metastatic liver tumors, who underwent both CT examinations and LUS as a part of a tumor ablation procedure. INTERVENTIONS: Triphasic spiral CT scans of the liver were obtained within 1 week before surgery. Liver LUS was performed with a linear 7.5-MHz side-viewing laparoscopic transducer. RESULTS: The LUS detected all 201 tumors seen on preoperative CT and detected 21 additional tumors (9.5%) in 11 patients (20.0%). These tumors missed by CT ranged in size from 0.3 to 2.7 cm. Smaller tumors tended to be missed by CT scan (28.6% of the lesions <1 cm, 15.8% of those 1-2 cm, 4% of those 2-3 cm, and 0% of those >3 cm), as did those in segments III and IV. There was good correlation between the size of lesions imaged by the 2 modalities (Pearson r = 0.86; P<.001). CONCLUSION: Laparoscopic ultrasound offers increased sensitivity over CT for the detection of liver tumors, especially for smaller lesions. This study documents the ability of LUS in detecting liver tumors and argues for more widespread use in laparoscopic staging procedures.     

CORR Insights®: Does Postoperative Glenoid Retroversion Affect the 2-Year Clinical and Radiographic Outcomes for Total Shoulder Arthroplasty?

Clinical Orthopaedics and Related Research® -     

Restricted Arp3 expression in the testis prevents blood–testis barrier disruption during junction restructuring at spermatogenesis

In epithelia, a primary damage of tight junctions (TJ) always leads to a secondary disruption of adherens junction (AJ), and vice versa. This response, if occurring in the testis, would disrupt spermatogenesis because the blood–testis barrier (BTB) must remain intact during the transit of spermatids in the seminiferous epithelium, which is associated with extensive apical ectoplasmic specialization (apical ES, a testis-specific AJ type) restructuring. As such, apical ES restructuring accompanied with the transit of developing spermatids during spermiogenesis must be segregated from the BTB to avoid an immunological barrier breakdown in all stages of the seminiferous epithelial cycle, except at stage VIII when spermiation and BTB restructuring take place concurrently. We report herein a mechanism involving restricted spatial and temporal expression of Arp2/3 complex and N-WASP, whose actin branching activity associated with apical ES and BTB restructuring in the seminiferous epithelium. High expression of Arp3 at the apical ES was shown to correlate with spermatid movement and proper spermatid orientation. Likewise, high Arp3 level at the BTB associated with its restructuring to accommodate the transit of preleptotene spermatocytes at stage VIII of the epithelial cycle. These findings were validated by in vitro and in vivo studies using wiskostatin, an inhibitor that blocks N-WASP from activating Arp2/3 complex to elicit actin branching. Inhibition of actin branching caused a failure of spermatid transit plus a loss of proper orientation in the epithelium, and a “tightened” Sertoli cell TJ permeability barrier, supporting the role of Arp2/3 complex in segregating the events of AJ and BTB restructuring.