Lumbar surgical drains do not increase the risk of infections in patients undergoing spine surgery.

PURPOSE: The aim of this study was to characterize if the use of surgical drains or length of drain placement following spine surgery increases the risk of post-operative infection. METHODS: Records of patients undergoing elective spinal surgery at a tertiary care center were collected between May 5, 2016 and August 16, 2018. Pre-operative baseline characteristics were recorded including patient's demographics and comorbidities. Intraoperative procedure information was documented related to procedure type, blood loss, and antibiotics used. Following surgery, patients were then further subdivided into two groups: patients who were discharged with a spinal surgical site drain and patients who did not receive a drain. Post-operative surgical variables included length of stay (LOS), drain length, number of antibiotics given, and type of post-operative infection. Univariate and multivariate statistical analysis was conducted. RESULTS: A total of 671 patients were included in the current study, 386 (57.5%) with and 285 (42.5%) without the drain. The overall infection rate was 5.7% with 6.22% among patients with the drain compared to 4.91% in patients without drain. The univariate analysis identified the following variables to be significantly associated with the infection: total number of surgical levels, spinal region, blood loss, redosing of antibiotics, length of stay, length of drain placement, and number of antibiotics (P < 0.05). However, the multivariate analysis none of the predictors was significant. CONCLUSIONS: The current study shows that the placement of drain does not increase rate of infection, irrespective of levels, length of surgery, or approach.

Impact of a Perioperative Protocol on Length of ICU and Hospital Stay in Complex Spine Surgery.

BACKGROUND: In an attempt to improve patient care, a perioperative complex spine surgery management protocol was developed through collaboration between spine surgeons and neuroanesthesiologists. The aim of this study was to investigate whether implementation of the protocol in 2015 decreased total hospital and intensive care unit (ICU) length of stay (LOS) and complication rates after elective complex spine surgery. MATERIALS AND METHODS: A retrospective cohort study was conducted by review of the medical charts of patients who underwent elective complex spine surgery at an academic medical center between 2012 and 2017. Patients were divided into 2 groups based on the date of their spine surgery in relation to implementation of the spine surgery protocol; before-protocol (January 2012 to March 2015) and protocol (April 2015 to March 2017) groups. Outcomes in the 2 groups were compared, focusing on hospital and ICU LOS, and complication rates. RESULTS: A total of 201 patients were included in the study; 107 and 94 in the before-protocol and protocol groups, respectively. Mean (SD) hospital LOS was 14.8±10.8 days in the before-protocol group compared with 10±10.7 days in the protocol group (P<0.001). The spine surgery protocol was the primary factor decreasing hospital LOS; incidence rate ratio 0.78 (P<0.001). Similarly, mean ICU LOS was lower in the protocol compared with before-protocol group (4.2±6.3 vs. 6.3±7.3 d, respectively; P=0.011). There were no significant differences in the rate of postoperative complications between the 2 groups (P=0.231). CONCLUSION: Implementation of a spine protocol reduced ICU and total hospital LOS stay in high-risk spine surgery patients.

Macrophage-derived HIV-1 carries bioactive TGF-beta.

Infected T cells and macrophages are the main producers of HIV-1 in infected individuals. Upon release from infected cells, HIV-1 incorporates various cellular membrane proteins, some of which are specific for these cells. However, the functions of cell-encoded proteins in virions remain largely unknown. We performed flow virometry to identify, in plasma of HIV-infected individuals, macrophage- and T-cell-derived HIV-1 virions, using cell-specific markers CD36 and CD27, respectively. Using four different methods, we demonstrated that CD36 on virions binds the immunosuppressive cytokine transforming growth factor beta (TGF-ß) through a ligand, thrombospondin one (TSP-1). Flow virometry of individual virions showed that TGF-ß was present on CD36+ virions (average, 28.2% ± 6.6% (n = 3)) but not on CD27+ virions (average, 1% ± 0.1% (n = 3)). TGF-ß molecules present on captured CD36+ virions were biologically active, as evaluated with a reporter cell line. Delivery of TGF-ß on HIV virions to HIV target cells may affect them, playing a significant role in viral pathogenesis.

Syncytin 1 dependent horizontal transfer of marker genes from retrovirally transduced cells.

Retroviral transduction is routinely used to generate cell lines expressing exogenous non-viral genes. Here, we show that human cells transduced to stably express GFP transfer GFP gene to non-transduced cells. This horizontal gene transfer was mediated by a fraction of extracellular membrane vesicles that were released by the transduced cells. These vesicles carried endogenous retroviral envelope protein syncytin 1 and essentially acted as replication-competent retroviruses. The ability to transfer the GFP gene correlated with the levels of syncytin 1 expression in the transduced cells and depended on the fusogenic activity of this protein, substantiating the hypothesis that endogenous syncytin 1 mediates fusion stage in the delivery of extracellular vesicle cargo into target cells. Our findings suggest that testing for replication-competent retroviruses, a routine safety test for transduced cell products in clinical studies, should be also carried out for cell lines generated by retroviral vectors in in vitro studies.

Recurrent Rathke's Cleft Cysts: Incidence and Surgical Management in a Tertiary Pituitary Center over 2 Decades.

BACKGROUND: Limited data exist pertaining to outcomes following surgery for recurrent Rathke's cleft cysts (RCC). OBJECTIVE: To determine treatment outcomes in patients undergoing reoperation for recurrent or residual RCCs. METHODS: A retrospective analysis of 112 consecutive RCC operations in 109 patients between 1995 and 2017 was conducted. RESULTS: Eighteen patients underwent 21 RCC reoperations with a mean follow-up of 58 mo. Patient symptoms prior to reoperation included headaches (14, 66.7%) and vision loss (12, 57.1%). Thirteen of 18 patients (72.2%) required hormone supplementation prior to reoperation including 5 with diabetes insipidus (DI). Mean RCC diameter was 16 mm and 76% had suprasellar extension. Compared to index RCC cases, intraoperative cerebrospinal fluid leak repair was more common in reoperation cases (15/21, 71% vs 43/91, 47%, P = .05). There was 1 carotid artery injury without neurological sequelae, and 2 postoperative cerebrospinal fluid (CSF) leaks (9.5%). Rates of transient hyponatremia (3/10, 30% vs 4/91, 4.4%, P = .04) and transient DI (5/10, 50% vs 17/91, 18.7%, P = .04) were higher in the reoperation vs index group. Improved headaches and vision were reported in 4/12 (33%) and 8/12 (61.5%) of RCC reoperation patients, respectively. Two patients developed new permanent DI. A higher proportion of reoperation patients had RCC squamous metaplasia (24% vs 5.4%, P = .02) or wall inflammation (42.9% vs 2.2%, P < .001) on pathological examination. CONCLUSION: Reoperation for RCCs is generally safe at tertiary pituitary centers and often results in improved vision. Hypopituitarism is less likely to improve following reoperation for recurrent RCCs. Several histopathological features may help characterize "atypical RCCs" with a higher likelihood of recurrence/progression.

Human cytomegalovirus-infected cells release extracellular vesicles that carry viral surface proteins.

Extracellular vesicles (EVs) released by virus-infected cells typically incorporate host and viral components inside the vesicles (cargo molecules). Here, we investigated if human cytomegalovirus (HCMV) proteins are incorporated in EV outer membrane released by HCMV-infected cells. We separated EVs from HCMV using an iodixanol step-gradient and found that the separated vesicles carried EV markers such as the tetraspanin CD63 and Rab27A. Flow analysis of individual EVs demonstrated that on average, 15 ±â€¯3.7% of EVs were positive for gB, 5.3 ±â€¯2.3% were positive for gH and 3.74 ±â€¯1.5% were positive for both gB and gH. In light of previous findings demonstrating HIV envelope proteins in EV membranes, the presence of viral protein at the surface of EVs released by HCMV-infected cells indicated that viral membrane proteins incorporated in EVs released by virus-infected cells may be a general phenomenon.

Select gp120 V2 domain specific antibodies derived from HIV and SIV infection and vaccination inhibit gp120 binding to α4ß7.

The GI tract is preferentially targeted during acute/early HIV-1 infection. Consequent damage to the gut plays a central role in HIV pathogenesis. The basis for preferential targeting of gut tissues is not well defined. Recombinant proteins and synthetic peptides derived from HIV and SIV gp120 bind directly to integrin α4ß7, a gut-homing receptor. Using both cell-surface expressed α4ß7 and a soluble α4ß7 heterodimer we demonstrate that its specific affinity for gp120 is similar to its affinity for MAdCAM (its natural ligand). The gp120 V2 domain preferentially engages extended forms of α4ß7 in a cation -sensitive manner and is inhibited by soluble MAdCAM. Thus, V2 mimics MAdCAM in the way that it binds to α4ß7, providing HIV a potential mechanism to discriminate between functionally distinct subsets of lymphocytes, including those with gut-homing potential. Furthermore, α4ß7 antagonists developed for the treatment of inflammatory bowel diseases, block V2 binding to α4ß7. A 15-amino acid V2 -derived peptide is sufficient to mediate binding to α4ß7. It includes the canonical LDV/I α4ß7 binding site, a cryptic epitope that lies 7-9 amino acids amino terminal to the LDV/I, and residues K169 and I181. These two residues were identified in a sieve analysis of the RV144 vaccine trial as sites of vaccine -mediated immune pressure. HIV and SIV V2 mAbs elicited by both vaccination and infection that recognize this peptide block V2-α4ß7 interactions. These mAbs recognize conformations absent from the ß- barrel presented in a stabilized HIV SOSIP gp120/41 trimer. The mimicry of MAdCAM-α4ß7 interactions by V2 may influence early events in HIV infection, particularly the rapid seeding of gut tissues, and supports the view that HIV replication in gut tissue is a central feature of HIV pathogenesis.

CD63, MHC class 1, and CD47 identify subsets of extracellular vesicles containing distinct populations of noncoding RNAs.

Extracellular vesicles (EVs) mediate the intercellular transfer of RNAs, which alter gene expression in target cells. EV heterogeneity has limited progress towards defining their physiological functions and utility as disease-specific biomarkers. CD63 and MHC1 are widely used as markers to purify EVs. CD47 is also present on EVs and alters their effects on target cells, suggesting that specific surface markers define functionally distinct EVs. This hypothesis was addressed by comparing Jurkat T cell EVs captured using CD47, CD63, and MHC1 antibodies. These EV subsets have similar sizes but divergent RNA contents. Apart from differences in numbers of nonannotated transcripts, CD63+, MHC1+, and CD47+ EVs have similar overall contents of most noncoding RNA classes, but the relative enrichment of specific RNAs differs. The enrichment of micro-RNAs is highly divergent, and some including miR320a are selectively concentrated in CD47+ EVs. Small nucleolar RNAs including SNORD116@ and SNHG10 are also selectively enriched in CD47+ EVs, whereas no small nuclear RNAs are enriched in CD47+ EVs. Conversely, MHC1+ EVs are selectively enriched in a subset of tRNAs including TRE-CTC and TRR-CCG. This heterogeneity in RNA composition suggests multiple sorting mechanisms that direct specific RNAs into subsets of EVs that express specific surface markers.

A function-blocking CD47 antibody modulates extracellular vesicle-mediated intercellular signaling between breast carcinoma cells and endothelial cells.

Tumor cells release extracellular vesicles (EVs) into the tumor microenvironment that may facilitate malignant progression and metastasis. Breast carcinoma EVs express high levels of the thrombospondin-1 and signal regulatory protein-α receptor CD47, which is the target of several experimental therapeutics currently in clinical trials. We analyzed changes in gene expression and function in human umbilical vein endothelial cells (HUVEC) induced by treatment with EVs derived from breast carcinoma cells and the effects of the function-blocking CD47 antibody B6H12 on the resulting intercellular communication. CD47+ EVs exhibited greater uptake by HUVEC compared to CD47- EVs, but the CD47 antibody did not inhibit their uptake. Global and targeted analyses of transcripts demonstrated that treatment of HUVEC with EVs derived from MDA-MB-231 breast carcinomas cells altered pathways associated with tumor necrosis factor-α signaling, angiogenesis, lymphangiogenesis, endothelial-mesenchymal transition, and extracellular matrix. EVs from triple-negative MDA-MB-231 cells were more active than EVs from less metastatic breast carcinoma cell lines. Treatment with MDA-MB-231 EVs down-regulated VEGFR2 mRNA expression and tyrosine phosphorylation while enhancing phosphorylation of the tyrosine phosphatase SHP2. VEGFR2 expression and phosphorylation in HUVEC was further inhibited by the CD47 antibody. Consistent with the observed changes in endothelial-mesenchymal transition genes and SHP2, treatment with MDA-MB-231-derived EVs decreased Zeb1 protein levels in HUVEC, whereas the CD47 antibody increased Zeb1 levels. The induction of E-selectin and other known targets of tumor necrosis factor-α signaling by EVs was also enhanced by the CD47 antibody, and E-selectin was the most up-regulated transcript following CD47 antibody treatment alone. These studies reveal several mechanisms by which therapeutics targeting CD47 could modulate tumor growth by altering the cross talk between cancer-derived EVs and nonmalignant cells in the tumor stroma.

Fusion Stage of HIV-1 Entry Depends on Virus-Induced Cell Surface Exposure of Phosphatidylserine.

HIV-1 entry into host cells starts with interactions between the viral envelope glycoprotein (Env) and cellular CD4 receptors and coreceptors. Previous work has suggested that efficient HIV entry also depends on intracellular signaling, but this remains controversial. Here we report that formation of the pre-fusion Env-CD4-coreceptor complexes triggers non-apoptotic cell surface exposure of the membrane lipid phosphatidylserine (PS). HIV-1-induced PS redistribution depends on Ca2+ signaling triggered by Env-coreceptor interactions and involves the lipid scramblase TMEM16F. Externalized PS strongly promotes Env-mediated membrane fusion and HIV-1 infection. Blocking externalized PS or suppressing TMEM16F inhibited Env-mediated fusion. Exogenously added PS promoted fusion, with fusion dependence on PS being especially strong for cells with low surface density of coreceptors. These findings suggest that cell-surface PS acts as an important cofactor that promotes the fusogenic restructuring of pre-fusion complexes and likely focuses the infection on cells conducive to PS signaling.

Monocytes but Not Lymphocytes Carrying HIV-1 on Their Surface Transmit Infection to Human Tissue Ex Vivo.

Unprotected sexual intercourse with HIV-infected men is the major cause of new infections. HIV virions are released into semen by various cells of the male genital tract, as well as by infected monocytes and lymphocytes present in semen. Some of these virions may attach to the surfaces of cells, infected or uninfected. We investigated whether cells carrying attached HIV on their surfaces can transmit infection. We addressed this question in a model system of human tissue exposed ex vivo to monocytes and lymphocytes carrying HIV on their surfaces. We gamma irradiated the cells to prevent their productive infection. In spite of comparable amounts of HIV attached to monocytes and lymphocytes, only monocytes were capable of transmitting infection and triggering productive infection in tissue. This HIV-1 transmission was mediated by cell-cell contacts. Our experiments suggest that in vivo, HIV attached to infected or uninfected monocytes, which far outnumber lymphocytes in HIV-infected semen, may contribute to sexual transmission of HIV from men to their partners. IMPORTANCE: The vast majority of new HIV infections occur through sexual transmission, in which HIV is transferred from the semen of an infected male to an uninfected partner. In semen, HIV-1 particles may exist as free-floating virions; inside infected cells; or attached to the surfaces of cells, whether they are infected or not. Here, we investigated whether HIV attached to the surfaces of monocytes or lymphocytes could transmit infection to human tissue. Incubation of human tissue with monocyte-attached HIV resulted in productive tissue infection. In contrast, there was no infection of tissues when they were incubated with lymphocyte-attached HIV-1. Our results highlight the important role that seminal monocytes may play in HIV transmission in vivo, especially since monocytes far outnumber lymphocytes in the semen of HIV-infected individuals.

Evaluation of the maturation of individual Dengue virions with flow virometry.

High-throughput techniques are needed to analyze individual virions to understand how viral heterogeneity translates into pathogenesis since in bulk analysis the individual characteristics of virions are lost. Individual Dengue virions (DENV) undergo a maturation that involves a proteolytic cleavage of prM precursor into virion-associated M protein. Here, using a new nanoparticle-based technology, "flow virometry", we compared the maturation of individual DENV produced by BHK-21 and LoVo cells. The latter lacks the furin-protease that mediates prM cleavage. We found that prM is present on about 50% of DENV particles produced in BHK-21 cells and about 85% of DENV virions produced in LoVo, indicating an increase in the fraction of not fully matured virions. Flow virometry allows us to quantify the number of fully mature particles in DENV preparations and proves to be a useful method for studying heterogeneity of the surface proteins of various viruses.

The association between dental health and procedures and developing shunt infections in pediatric patients.

OBJECT: Cerebrospinal fluid-diverting shunts are often complicated by bacterial infections. Dental procedures are known to cause transient bacteremia that could potentially spread hematogenously to these implanted devices. No literature currently exists to inform practitioners as to the need for prophylactic antibiotics for patients who possess these implants. The authors performed a retrospective study to assess whether dental procedures and poor oral health were associated with a higher likelihood of developing CSF-diverting shunt infections. METHODS: Neurosurgical and pediatric dental records from January 2007 to December 2012 were reviewed for shunt surgeries and dental encounters. Indications for shunt surgery and infection rates were recorded. Dental records were reviewed for several markers of overall dental health, such as a DMFT (decayed, missing, and filled teeth) score and a gingival health/oral hygiene score. The association between these scores and the incidence of shunt infections were studied. Moreover, the relationship between the incidence of shunt infections and the timing and invasiveness of preceding dental encounters were analyzed. RESULTS: A total of 100 pediatric patients were included in our study, for a total of 204 shunt surgeries. Twenty-one shunt infections were noted during the 6-year study period. Five of these shunts infections occurred within 3 months of a dental procedure. The odds ratio (OR) of developing a shunt infection within 3 months of a dental procedure was 0.98 (95% confidence interval [CI] 0.27-3.01), and was not statistically significant. The OR of developing a shunt infection after a high-risk dental procedure compared with a low-risk dental procedure was 1.32 (95% CI 0.02-16.29), and was not statistically significant. There was no significant association between measures of dental health, such as DMFT and gingival health score, and the likelihood of developing a shunt infection. The ORs for these 2 scores were 0.51 (95% CI 0.04-4.96) and 1.58 (95% CI 0.03-20.06), respectively. The study was limited by sample size. CONCLUSIONS: Dental health status and the number and type of dental procedures performed do not appear to confer a higher risk of developing a CSF-diverting shunt infection in this pediatric population.