Reduced racial disparities among newborns with intraventricular hemorrhage

INTRODUCTION

Intraventricular hemorrhage (IVH) can ensue permanent neurologic dysfunction, morbidity, and mortality. While previous reports have identified disparities based on patient gender or weight, no prior study has assessed how race may influence in neonatal or infantile IVH patients. The aim of this study was to investigate the impact of race on adverse event (AE) rates, length of stay (LOS), and total cost of admission among newborns with IVH.

METHODS

Using the 2016-2019 National Inpatient Sample database, newborns diagnosed with IVH were identified using ICD-10-CM codes. Patients were stratified based on race. Patient characteristics and inpatient outcomes were assessed. Multivariate logistic regression analyses were used to identify the impact of race on extended LOS and exorbitant cost.

RESULTS

Of 1435 patients, 650 were White (45.3%), 270 African American (AA) (18.8%), 300 Hispanic (20.9%), and 215 Other (15.0%). A higher percentage of AA and Other patients than Hispanic and White patients were < 28 days old (p = 0.008). Each of the cohorts had largely similar presenting comorbidities and symptoms, although AA patients did have significantly higher rates of NEC (p < 0.001). There were no observed differences in rates of AEs, rates of mortality, mean LOS, or mean total cost of admission. Similarly, on multivariate analysis, no race was identified as a significant independent predictor of extended LOS or exorbitant cost.

CONCLUSIONS

Our study found that in newborns with IVH, race is not associated with proxies of poor healthcare outcomes like prolonged LOS or excessive cost. Further studies are needed to validate these findings.

Racial/Ethnic Disparities Among Patients Undergoing Anterior Cervical Discectomy and Fusion or Posterior Cervical Decompression and Fusion for Cervical Spondylotic Myelopathy: A National Administrative Database Analysis

INTRODUCTION

The aim of this study was to investigate the impact of racial disparities on surgical outcomes for cervical spondylotic myelopathy (CSM).

METHODS

Adult patients undergoing anterior cervical discectomy and fusion (ACDF) or posterior cervical decompression and fusion (PCDF) for CSM were identified from the 2016 to 019 National Inpatient Sample Database using the International Classification of Diseases codes. Patients were categorized based on approach (ACDF or PCDF) and race/ethnicity (White, Black, Hispanic). Patient demographics, comorbidities, operative characteristics, adverse events, and health care resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of extended length of stay (LOS), nonroutine discharge (NRD), and exorbitant costs.

RESULTS

A total of 46,500 patients were identified, of which 36,015 (77.5%) were White, 7465 (16.0%) were Black, and 3020 (6.5%) were Hispanic. Black and Hispanic patients had a greater comorbidity burden compared to White patients (P = 0.001) and a greater incidence of any postoperative complication (P = 0.001). Healthcare resource utilization were greater in the PCDF cohort than the ACDF cohort and greater in Black and Hispanic patients compared to White patients (P < 0.001). Black and Hispanic patient race were significantly associated with extended hospital LOS ([Black] odds ratio [OR]: 2.24, P < 0.001; [Hispanic] OR: 1.64, P < 0.001) and NRD ([Black] OR: 2.33, P < 0.001; [Hispanic] OR: 1.49, P = 0.016). Among patients who underwent PCDF, Black race was independently associated with extended hospital LOS ([Black] OR: 1.77, P < 0.001; [Hispanic] OR: 1.47, P = 0.167) and NRD ([Black] OR: 1.82, P < 0.001; [Hispanic] OR: 1.38, P = 0.052).

CONCLUSIONS

Our study suggests that patient race may influence patient outcomes and healthcare resource utilization following ACDF or PCDF for CSM.

Implications of Frailty on Postoperative Health Care Resource Utilization in Ankylosing Spondylitis Patients Undergoing Spine Surgery for Spinal Fractures

OBJECTIVE

The rise of spinal surgery for ankylosing spondylitis (AS) necessitates balancing health care costs with quality patient care. Frailty has been independently associated with adverse outcomes and increased costs. This study investigates whether frailty is an independent predictor of poor outcomes after elective surgery for AS.

METHODS

Using the National Inpatient Sample (NIS) database, a retrospective study was conducted on adult patients with AS who underwent posterior spinal fusion for fracture between 2016 and 2019. Each patient was assigned a modified frailty index (mFI) score and categorized as prefrail (mFI = 0 or 1), moderately frail (mFI = 2), and highly frail (mFI≥3). Multivariate logistic regression analyses were used to identify independent predictors of extended length of stay, non-routine discharge (NRD), and exorbitant admission costs.

RESULTS

Of the 1910 patients, 35.3% were prefrail, 31.2% moderately frail, and 33.5% highly frail. Age was significantly different across groups (P < 0.001), and frailty was associated with increased comorbidities (P < 0.001). Mean length of stay (P = 0.007), NRD rate (P < 0.001), and mean cost of admission (P = 0.002) all significantly increased with increasing frailty. However, frailty was not an independent predictor of extended hospital stay, NRD, or higher costs on multivariate analysis. Instead, predictors included multiple adverse events, number of comorbidities, and race.

CONCLUSIONS

While frailty in patients with AS is associated with older age, greater comorbidities, and increased adverse events, it was not an independent predictor of extended hospital stay, NRD, or higher hospital costs. Further research is required to understand the full impact of frailty on surgical outcomes and develop effective interventions.

Influence of affective disorders on outcomes after suboccipital decompression for adult Chiari I malformation

INTRODUCTION

Affective disorders (AD) have been shown to influence patient outcomes and healthcare resource utilization across several pathologies, though this relationship has not been described in patients with Chiari I malformations (CM-I). The aim of this study was to determine the impact of comorbid AD on postoperative events and healthcare resource utilization in adults following suboccipital decompression for CM-I.

METHODS

A retrospective study was performed using the 2016-2019 National Inpatient Sample database. Adults who underwent suboccipital decompression for CM-I were identified using ICD-10-CM codes. Patients were stratified into two cohorts, those with AD and those without (No AD). Patient demographics, comorbidities, operative characteristics, perioperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of prolonged length of stay (LOS), exorbitant admission costs, and non-routine discharge (NRD).

RESULTS

A total of 3985 patients were identified, of which 2780 (69.8%) were in the No AD cohort and 1205 (30.2%) were in the AD cohort. Patient demographics were similar, except for a greater proportion of Female patients than the No AD cohort (p = 0.004). Prevalence of some comorbidities varied between cohorts, including obesity (p = 0.030), ADHD (p < 0.001), GERD (p < 0.001), smoking (p < 0.001), and chronic pulmonary disease (p < 0.001). The AD cohort had a greater proportion of patients with 1-2 (p < 0.001) or ≥ 3 comorbidities (p < 0.001) compared to the No AD cohort. A greater proportion of patients in the AD cohort presented with headache compared to the No AD cohort (p = 0.003). Incidence of syringomyelia was greater in the No AD cohort (p = 0.002). A greater proportion of patients in the No AD cohort underwent duraplasty only (without cervical laminectomy) compared to the AD cohort (p = 0.021). Healthcare resource utilization was similar between cohorts, with no significant differences in mean LOS (No AD: 3.78 ± 3.51 days vs. 3.68 ± 2.71 days, p = 0.659), NRD (No AD: 3.8% vs. AD: 5.4%, p = 0.260), or mean admission costs (No AD: $20,254 ± 14,023 vs. AD: $29,897 ± 22,586, p = 0.284). On multivariate analysis, AD was not independently associated with extended LOS [OR (95%CI): 1.09 (0.72-1.65), p = 0.669], increased hospital costs [OR (95%CI): 0.98 (0.63-1.52), p = 0.930], or NRD [OR (95%CI): 1.39 (0.65-2.96), p = 0.302].

CONCLUSION

Our study suggests that the presence of an AD may not have as much of an impact on postoperative events and healthcare resource utilization in adult patients undergoing Chiari decompression. Additional studies may be warranted to identify other potential implications that AD may have in other aspects of healthcare in this patient population.

Racial disparities in the management and outcomes of primary osseous neoplasms of the spine: a SEER analysis

PURPOSE

Primary osseous neoplasms of the spine, including Ewing's sarcoma, osteosarcoma, chondrosarcoma, and chordoma, are rare tumors with significant morbidity and mortality. The present study aims to identify the prevalence and impact of racial disparities on management and outcomes of patients with these malignancies.

METHODS

The 2000 to 2020 Surveillance, Epidemiology, and End Results (SEER) Registry, a cancer registry, was retrospectively reviewed to identify patients with Ewing's sarcoma, osteosarcoma, chondrosarcoma, or chordoma of the vertebral column or sacrum/pelvis. Study patients were divided into race-based cohorts: White, Black, Hispanic, and Other. Demographics, tumor characteristics, treatment variables, and mortality were assessed.

RESULTS

2,415 patients were identified, of which 69.8% were White, 5.8% Black, 16.1% Hispanic, and 8.4% classified as "Other". Tumor type varied significantly between cohorts, with osteosarcoma affecting a greater proportion of Black patients compared to the others (p < 0.001). A lower proportion of Black and Other race patients received surgery compared to White and Hispanic patients (p < 0.001). Utilization of chemotherapy was highest in the Hispanic cohort (p < 0.001), though use of radiotherapy was similar across cohorts (p = 0.123). Five-year survival (p < 0.001) and median survival were greatest in White patients (p < 0.001). Compared to non-Hispanic Whites, Hispanic (p < 0.001) and "Other" patients (p < 0.001) were associated with reduced survival.

CONCLUSION

Race may be associated with tumor characteristics at diagnosis (including subtype, size, and site), treatment utilization, and mortality, with non-White patients having lower survival compared to White patients. Further studies are necessary to identify underlying causes of these disparities and solutions for eliminating them.

Impact of Preoperative Frailty on Outcomes in Patients with Cervical Spondylotic Myelopathy Undergoing Anterior vs. Posterior Cervical Surgery

Introduction: Frailty has been shown to negatively influence patient outcomes across many disease processes, including in the cervical spondylotic myelopathy (CSM) population. The aim of this study was to assess the impact that frailty has on patients with CSM who undergo anterior cervical discectomy and fusion (ACDF) or posterior cervical decompression and fusion (PCDF). Materials and Methods: A retrospective cohort study was performed using the 2016-2019 national inpatient sample. Adult patients (≥18 years old) undergoing ACDF only or PCDF only for CSM were identified using ICD codes. The patients were categorized based on receipt of ACDF or PCDF and pre-operative frailty status using the 11-item modified frailty index (mFI-11): pre-Frail (mFI = 1), frail (mFI = 2), or severely frail (mFI ≥ 3). Patient demographics, comorbidities, operative characteristics, perioperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of extended length of stay (LOS) and non-routine discharge (NRD). Results: A total of 37,990 patients were identified, of which 16,665 (43.9%) were in the pre-frail cohort, 12,985 (34.2%) were in the frail cohort, and 8340 (22.0%) were in the severely frail cohort. The prevalence of many comorbidities varied significantly between frailty cohorts. Across all three frailty cohorts, the incidence of AEs was greater in patients who underwent PCDF, with dysphagia being significantly more common in patients who underwent ACDF. Additionally, the rate of adverse events significantly increased between ACDF and PCDF with respect to increasing frailty (p < 0.001). Regarding healthcare resource utilization, LOS and rate of NRD were significantly greater in patients who underwent PCDF in all three frailty cohorts, with these metrics increasing with frailty in both ACDF and PCDF cohorts (LOS: p < 0.001); NRD: p < 0.001). On a multivariate analysis of patients who underwent ACDF, frailty and severe frailty were found to be independent predictors of extended LOS [(frail) OR: 1.39, p < 0.001; (severely frail) OR: 2.25, p < 0.001] and NRD [(frail) OR: 1.49, p < 0.001; (severely frail) OR: 2.22, p < 0.001]. Similarly, in patients who underwent PCDF, frailty and severe frailty were found to be independent predictors of extended LOS [(frail) OR: 1.58, p < 0.001; (severely frail) OR: 2.45, p < 0.001] and NRD [(frail) OR: 1.55, p < 0.001; (severely frail) OR: 1.63, p < 0.001]. Conclusions: Our study suggests that preoperative frailty may impact outcomes after surgical treatment for CSM, with more frail patients having greater health care utilization and a higher rate of adverse events. The patients undergoing PCDF ensued increased health care utilization, compared to ACDF, whereas severely frail patients undergoing PCDF tended to have the longest length of stay and highest rate of non-routine discharge. Additional prospective studies are necessary to directly compare ACDF and PCDF in frail patients with CSM.

Associated Risk Factors for Extended Length of Stay Following Cranial Vault Remodeling for Craniosynostosis: Analysis of the 2012 to 2021 NSQIP-Pediatric Database

OBJECTIVES

The aim of this study was to identify the factors associated with extended length of stay (LOS) for pediatric patients with craniosynostosis undergoing cranial vault remodeling (CVR).

METHODS

A retrospective cohort study was performed using the 2012 to 2021 American College of Surgeons National Surgical Quality Improvement Program-Pediatric database. Pediatric patients below 2 years old with craniosynostosis who underwent CVR were identified using Current Procedural Terminology and International Classification of Diseases-9/10 codes. Patients were dichotomized according to whether they encountered an extended postoperative hospital LOS, which was defined as LOS greater than the 75th percentile for the entire cohort (4 days). Patient demographics, comorbidities, intraoperative variables, postoperative adverse events, and health care resource utilization were assessed. Multivariate logistic regression analysis was utilized to identify predictors of prolonged LOS.

RESULTS

In our cohort of 9784 patients, 1312 (13.4%) experienced an extended LOS. The extended LOS cohort was significantly older than the normal LOS cohort (normal LOS: 225.1±141.8 d vs. extended LOS: 314.4±151.7 d, P<0.001) and had a smaller proportion of non-Hispanic white patients (normal LOS: 70.0% vs. extended LOS: 61.2%, P<0.001). Overall, comorbidities and adverse events were significantly higher in the extended LOS cohort than the normal LOS cohort. On multivariate logistic regression, independent associations of extended LOS included age, race and ethnicity, weight, American Society of Anesthesiologists classification, impaired cognitive status, structural pulmonary abnormalities, asthma, and neuromuscular disorders.

CONCLUSIONS

This study demonstrates that age, race, comorbidities, and perioperative complications contribute to extended LOS after CVR for craniosynostosis. Further investigations to further elucidate the risk factors of extended LOS is warranted to optimize patient outcomes.

Association of frailty with healthcare resource utilization after open thoracic/thoracolumbar posterior spinal fusion for adult spinal deformity

PURPOSE

The Hospital Frailty Risk Score (HFRS) is a frailty-identifying metric developed using ICD-10-CM codes. While other studies have examined frailty in adult spinal deformity (ASD), the HFRS has not been assessed in this population. The aim of this study was to utilize the HFRS to investigate the impact of frailty on outcomes in ASD patients undergoing posterior spinal fusion (PSF).

METHODS

A retrospective study was performed using the 2016-2019 National Inpatient Sample database. Adults with ASD undergoing elective PSF were identified using ICD-10-CM codes. Patients were categorized into HFRS-based frailty cohorts: Low (HFRS < 5) and Intermediate-High (HFRS ≥ 5). Patient demographics, comorbidities, intraoperative variables, and outcomes were assessed. Multivariate regression analyses were used to determine whether HFRS independently predicted extended length of stay (LOS), non-routine discharge, and increased cost.

RESULTS

Of the 7500 patients identified, 4000 (53.3%) were in the Low HFRS cohort and 3500 (46.7%) were in the Intermediate-High HFRS cohort. On average, age increased progressively with increasing HFRS scores (p < 0.001). The frail cohort experienced more postoperative adverse events (p < 0.001), greater LOS (p < 0.001), accrued greater admission costs (p < 0.001), and had a higher rate of non-routine discharge (p < 0.001). On multivariate analysis, Intermediate-High HFRS was independently associated with extended LOS (OR: 2.58, p < 0.001) and non-routine discharge (OR: 1.63, p < 0.001), though not increased admission cost (OR: 1.01, p = 0.929).

CONCLUSION

Our study identified HFRS to be significantly associated with prolonged hospitalizations and non-routine discharge. Other factors that were found to be associated with increased healthcare resource utilization include age, Hispanic race, West hospital region, large hospital size, and increasing number of AEs.

Prevalence and Influence of Frailty on Hospital Outcomes After Surgical Resection of Spinal Meningiomas

OBJECTIVE

Frailty has been shown to affect patient outcomes after medical and surgical interventions. The Hospital Frailty Risk Score (HFRS) is a growing metric used to assess patient frailty using International Classification of Diseases, Tenth Revision codes. The goal of this study was to investigate the impact of frailty, assessed by HFRS, on health care resource utilization and outcomes in patients undergoing surgery for spinal meningiomas.

METHODS

A retrospective cohort study was performed using the 2016-2019 National Inpatient Sample database. Adult patients with benign or malignant spinal meningiomas, identified using International Classification of Diseases, Tenth Revision, Clinical Modification codes, were stratified by HFRS: low frailty (HFRS <5) and intermediate-high frailty (HFRS ≥5). Patient demographics, hospital characteristics, comorbidities, procedural variables, adverse events, length of stay (LOS), discharge disposition, and cost of admission were assessed. Multivariate regression analysis was used to identify predictors of increased LOS, discharge disposition, and cost.

RESULTS

Of the 3345 patients, 530 (15.8%) had intermediate-high frailty. The intermediate-high cohort was significantly older (P < 0.001). More patients in the intermediate-high cohort had ≥3 comorbidities (P < 0.001). In addition, a greater proportion of patients in the intermediate-high cohort experienced ≥1 perioperative adverse events (P < 0.001). Intermediate-high patients experienced greater mean LOS (P < 0.001) and accrued greater costs (P < 0.001). A greater proportion of intermediate-high patients had nonroutine discharges (P < 0.001). On multivariate analysis, increased HFRS (≥5) was independently associated with extended LOS (adjusted odds ratio [aOR], 3.04; P < 0.001), nonroutine discharge (aOR, 1.98; P = 0.006), and increased costs (aOR, 2.39; P = 0.004).

CONCLUSIONS

Frailty may be associated with increased health care resource utilization in patients undergoing surgery for spinal meningiomas.

A current review of spinal meningiomas: epidemiology, clinical presentation and management

PURPOSE

To provide an up-to-date review of the epidemiology, histopathology, molecular biology, and etiology of spinal meningiomas, as well as discuss the clinical presentation, clinical evaluation, and most recent treatment recommendations for these lesions.

METHODS

PubMed and Google Scholar search was performed for studies related to meningiomas of the spine. The terms "meningioma," "spinal meningioma," "spine meningioma," "meningioma of the spine," "benign spinal tumors," and "benign spine tumors," were used to identify relevant studies. All studies, including primary data papers, meta-analyses, systematic reviews, general reviews, case reports, and clinical trials were considered for review.

RESULTS

Eighty-four studies were identified in the review. There were 22 studies discussing adverse postoperative outcomes, 21 studies discussing tumor genetics, 19 studies discussing epidemiology and current literature, 9 studies discussing radiation modalities and impact on subsequent tumor development, 5 studies on characteristic imaging findings, 5 studies discussing hormone use/receptor status on tumor development, 2 discussing operative techniques and 1 discussing tumor identification.

CONCLUSION

Investigations into spinal meningiomas generally lag behind that of intracranial meningiomas. Recent advancements in the molecular profiling of spinal meningiomas has expanded our understanding of these tumors, increasing our appreciation for their heterogeneity. Continued investigation into the defining characteristics of different spinal meningiomas will aid in treatment planning and prognostication.

Enrichment of Placental Trophoblast Cells from Clinical Cervical Samples Using Differences in Surface Adhesion on an Inclined Plane

Placental trophoblast cells present in cervical samples have great potential towards non-invasive prenatal testing. However, cervical samples are highly heterogeneous, largely comprised of maternal cervical cells with only a small quantity of trophoblast cells. In order to use these rare cells for diagnostic applications, there is a need to enrich and isolate them from the heterogeneous maternal sample. Our goal was to investigate the use of gravitational flow on an inclined surface and optimize parameters including angle of incline, surface material, incubation time on the surface, solution volume, and device channel width in order to identify a design allowing label-free enrichment of trophoblast cells. In this work we detail the development of a new method and device for controlling cell adhesion to a surface vs. rolling into a collection area. The enrichment device design was developed for ease of use by non-specialized personal and on a slide surface for the ability to be directly integrated onto an automatic cell picker instrument, which can be used for downstream single cell isolation. JEG-3 trophoblast cells were used with clinical cervical samples to present the effect of the different optimization parameters on enrichment. We further provide an assessment of the impact shear stress and thickness of the liquid layer has on cell enrichment. We found that this method provides a maximum JEG-3 enrichment using polystyrene surfaces at a 50° incline with a 5 min incubation period prior to inclined flow. This resulted in a 396 ± 52% increase in purity of the trophoblast cells from the clinical cervical samples as confirmed using human leukocyte antigen G (HLA-G) antibody staining with fluorescence imaging to identify JEG-3 cells. Ultimately, this method is inexpensive, quick, and has the potential for direct integration into fetal cell isolation platforms.

Incidence of thyroid cancer in England by ethnic group, 2001-2007

BACKGROUND

Thyroid cancer incidence is increasing worldwide, but with large variations in incidence that may reflect either diagnostic bias or true ethnic differences. We sought to determine the effect of ethnicity on the incidence of thyroid cancer in England, a multiethnic population with a single health-care system.

METHODS

We analysed 11,263 thyroid cancer registrations with ethnicity obtained by linkage to the Hospital Episodes Statistics database. Incidence rate ratios (RRs) adjusted for age, sex and income were calculated for the six main non-White ethnic groups in England compared with Whites and to each other.

RESULTS

Thyroid cancer incidence was higher in all ethnic groups, except Indians, compared with Whites: in Pakistanis (RR 1.79, 99% floating confidence interval (FCI) 1.47-2.19); Bangladeshis (RR 1.99, 99% FCI 1.46-2.71); Black Africans (RR 1.69, 99% FCI 1.34-2.13); Black Caribbeans (RR 1.56, 99% FCI 1.25-1.93); and Chinese (RR 2.14, 99% FCI 1.63-2.80).

CONCLUSION

The risk of thyroid cancer in England varies significantly by ethnicity. The elevated incidence in most ethnic minorities is unlikely to be due to diagnostic bias and warrants further investigation.

The effect of Clostridium perfringens type C strain CN3685 and its isogenic beta toxin null mutant in goats

Clostridium perfringens type C is an important cause of enteritis and/or enterocolitis in several animal species, including pigs, sheep, goats, horses and humans. The disease is a classic enterotoxemia and the enteric lesions and associated systemic effects are thought to be caused primarily by beta toxin (CPB), one of two typing toxins produced by C. perfringens type C. This has been demonstrated recently by fulfilling molecular Koch's postulates in rabbits and mice. We present here an experimental study to fulfill these postulates in goats, a natural host of C. perfringens type C disease. Nine healthy male or female Anglo Nubian goat kids were inoculated with the virulent C. perfringens type C wild-type strain CN3685, an isogenic CPB null mutant or a strain where the cpb null mutation had been reversed. Three goats inoculated with the wild-type strain presented abdominal pain, hemorrhagic diarrhea, necrotizing enterocolitis, pulmonary edema, hydropericardium and death within 24h of inoculation. Two goats inoculated with the CPB null mutant and two goats inoculated with sterile culture media (negative controls) remained clinically healthy during 24h after inoculation and no gross or histological abnormalities were observed in the tissues of any of them. Reversal of the null mutation to partially restore CPB production also increased virulence; 2 goats inoculated with this reversed mutant presented clinical and pathological changes similar to those observed in goats inoculated with the wild-type strain, except that spontaneous death was not observed. These results indicate that CPB is required for C. perfringens type C to induce disease in goats, supporting a key role for this toxin in natural C. perfringens type C disease pathogenesis.

The Gore Excluder endograft device for the treatment of abdominal aortic aneurysms

Open surgical repair on abdominal aortic aneurysms has been performed for many years with good

RESULTS

Despite the many advances in medical care, the procedure is still associated with many complications. The Gore Excluder endograft is a third-generation endograft that became the third commercially available endograft approved in the United States. Data from multiple trials have compared the use of the Excluder endograft to open repair and have shown favorable

RESULTS

This review shall summarize the clinical use of the Excluder endograft from its initial clinical trial in 1998 to its current commercial use.

The enteric toxins of Clostridium perfringens

The Gram-positive pathogen Clostridium perfringens is a major cause of human and veterinary enteric disease largely because this bacterium can produce several toxins when present inside the gastrointestinal tract. The enteric toxins of C. perfringens share two common features: (1) they are all single polypeptides of modest (approximately 25-35 kDa) size, although lacking in sequence homology, and (2) they generally act by forming pores or channels in plasma membranes of host cells. These enteric toxins include C. perfringens enterotoxin (CPE), which is responsible for the symptoms of a common human food poisoning and acts by forming pores after interacting with intestinal tight junction proteins. Two other C. perfringens enteric toxins, epsilon-toxin (a bioterrorism select agent) and beta-toxin, cause veterinary enterotoxemias when absorbed from the intestines; beta- and epsilon-toxins then apparently act by forming oligomeric pores in intestinal or extra-intestinal target tissues. The action of a newly discovered C. perfringens enteric toxin, beta2 toxin, has not yet been defined but precedent suggests it might also be a pore-former. Experience with other clostridial toxins certainly warrants continued research on these C. perfringens enteric toxins to develop their potential as therapeutic agents and tools for cellular biology.

The stability region of the large virulence plasmid of Shigella flexneri encodes an efficient postsegregational killing system

The large virulence plasmid pMYSH6000 of Shigella flexneri contains a determinant that is highly effective in stabilizing otherwise unstable plasmids in Escherichia coli. Expression of two small contiguous genes, mvpA and mvpT (formerly termed STBORF1 and STBORF2), was shown to be sufficient for stability. Mutations in mvpT abolished plasmid stability, and plasmids expressing only mvpT killed the cells unless mvpA was supplied from a separate plasmid or from the host chromosome. When replication of a plasmid carrying the minimal mvp region was blocked, growth of the culture stopped after a short lag and virtually all of the surviving cells retained the plasmid. Thus, the mvp system stabilizes by a highly efficient postsegregational killing (PSK) mechanism, with mvpT encoding a cell toxin and mvpA encoding an antidote. The regions that surround the mvp genes in their original context have an inhibitory effect that attenuates plasmid stabilization and PSK. The region encompassing the mvp genes also appears to contain an additional element that can aid propagation of a pSC101-based plasmid under conditions where replication initiation is marginal. However, this appears to be a relatively nonspecific effect of DNA insertion into the plasmid vector.

The ERK-1/2 signaling pathway is involved in the stimulation of branching morphogenesis of fetal mouse submandibular glands by EGF

We have previously reported that epidermal growth factor (EGF) stimulates branching morphogenesis of the fetal mouse submandibular gland (SMG) (M. Kashimata and E. W. Gresik, 1997, Dev. Dyn. 208, 149-161) and that the EGF receptor (EGFR) is localized principally, if not exclusively, on the epithelial components of the fetal SMG (E. W. Gresik, M. Kashimata, Y. Kadoya, R. Mathews, N. Minami, and S. Yamashina, 1997, J. Histochem. Cytochem. 45, 1651-1657). The EGFR is a receptor tyrosine kinase, and after binding of its ligand, it triggers several intracellular signaling cascades, among them the one activating the mitogen-activated protein kinases (MAPK) ERK-1/2. Here we investigated whether EGF utilizes the ERK-1/2 signaling cascade to stimulate branching morphogenesis in the fetal mouse SMG. SMG rudiments were collected as matched pairs at E14, E16, and E18 (E0 = day of vaginal plug); placed into wells of defined medium (BGJb); and exposed to EGF for 5 or 30 min or to medium alone (controls). By Western blotting we found that EGF induced the appearance of multiple bands of phosphotyrosine-containing proteins, including bands at 170 kDa and 44 kDa/42 kDa, presumably corresponding to the phosphorylated forms of EGFR and ERK-1/2, respectively. Other blots showed the specific appearance of the phosphorylated EGFR and of phospho-ERK-1/2 in response to EGF. Immunohistochemical staining for phosphotyrosine increased at the plasma membrane after EGF stimulation for 5 or 30 min. Diffuse cytoplasmic staining for MEK-1/2 (the MAPK kinase that activates ERK-1/2) increased near the cell membrane after EGF stimulation. Phospho-ERK-1/2 was localized in the nuclei of a few epithelial cells after EGF for 5 min, but in the nuclei of many cells after EGF for 30 min. PD98059, an inhibitor of phosphorylation and activation of MEK-1/2, by itself inhibited branching morphogenesis and, furthermore, decreased the stimulatory effect of EGF on branching. Western blots confirmed that this inhibitor blocked phosphorylation of ERK-1/2 in fetal SMGs exposed to EGF. These results show that components of the ERK-1/2 signaling cascade are present in epithelial cells of the fetal SMG, that they are activated by EGF, and that inhibition of this cascade perturbs branching morphogenesis. However, EGF did not cause phosphorylation of two other MAPKs, SAPK/JNK or p38MAPK, in fetal SMGs. These results imply that the ERK-1/2 signaling is responsible, at least in part, for the stimulatory effect of EGF on branching morphogenesis of the fetal mouse SMG.

Cytotoxic sensitivity to tumor necrosis factor-alpha in PC3 and LNCaP prostatic cancer cells is regulated by extracellular levels of SGP-2 (clusterin)

BACKGROUND

SGP-2 is a ubiquitous secreted glycoprotein that prevents cellular apoptosis. This study was carried out to determine the extracellular action of SGP-2 in a model of tumor necrosis factor-alpha (TNF)-induced cytotoxicity using two human prostatic cancer lines, LNCaP and PC3. These two lines were selected because LNCaP cells are highly sensitive to the cytotoxic effect of TNF, while PC3 cells are resistant to TNF at 24 hr.

METHODS

Cells were cultured in the presence or absence of TNF (10 ng/ml). LNCaP cells were treated with varying concentrations of exogenous SGP-2, while PC3 cells were treated with antisera to SGP-2 with and without exogenous SGP-2. Following a 24-hr treatment, cultures were assessed by counting of cell number and by the trypan blue exclusion assay.

RESULTS

Western blot analysis of conditioned media revealed that PC3 secreted more SGP-2 than did LNCaP. The sensitivity to TNF in LNCaP cells was reduced by the addition of exogenous SGP-2. PC3 cells became sensitive to TNF when SGP-2 antibody was added to the culture. The effect of SGP-2 antibody on PC3 cells was reversed by the addition of exogenous SGP-2 to the culture.

CONCLUSIONS

These results suggest that SGP-2 can act as an extracellular mediator of anti-TNF-induced cytotoxicity.

CpG motifs in bacterial DNA cause inflammation in the lower respiratory tract

Since unmethylated CpG motifs are more frequent in DNA from bacteria than vertebrates, and the unmethylated CpG motif has recently been reported to have stimulatory effects on lymphocytes, we speculated that bacterial DNA may induce inflammation in the lower respiratory tract through its content of unmethylated CpG motifs. To determine the role of bacterial DNA in lower airway inflammation, we intratracheally instilled prokaryotic and eukaryotic DNA in C3H/HeBFEJ mice and performed whole lung lavage 4 h after the exposure. Heat denatured, single stranded Escherichia coli genomic DNA (0.06 ng endotoxin/microg DNA) was compared to heat denatured, single stranded calf thymus DNA (0.007 endotoxin/microg DNA). 10 microg of bacterial DNA, in comparison to 10 microg of calf thymus DNA, resulted in a fourfold increase in the concentration of cells (P = 0.0002), a fivefold increase in the concentration of neutrophils (P = 0.0002), a 50-fold increase in the concentration of TNF-alpha (P = 0.001), and a fourfold increase in the concentration of both IL-6 (P = 0.0003) and macrophage inflammatory protein-2 (P = 0.0001) in the lavage fluid. Importantly, instillation of 0.60 ng of E. coli LPS resulted in a negligible inflammatory response. To test whether the stimulatory effects of bacterial DNA are due to its unmethylated CpG dinucleotides, we methylated the bacterial DNA and also prepared 20 base pair oligonucleotides with and without CpG motifs. In comparison to instillation of untreated bacterial DNA, methylation of the bacterial DNA resulted in a significant reduction in the concentration of cells and cytokines in the lower respiratory tract. Moreover, oligonucleotides containing embedded unmethylated CpG motifs resulted in inflammation in the lower respiratory tract that was indistinguishable from that observed with untreated bacterial DNA. In contrast, oligonucleotides without the embedded CpG motifs or with embedded but methylated CpG motifs resulted in significantly less inflammation in the lower respiratory tract. The possible relevance of these data to human disease was shown by extracting and analyzing DNA in sputum from patients with cystic fibrosis (CF). Approximately 0.1 to 1% of this sputum DNA was bacterial. Intratracheal instillation of highly purified CF sputum DNA caused acute inflammation similar to that induced by bacterial DNA. These findings suggest that bacterial DNA, and unmethylated CpG motifs in particular, may play an important pathogenic role in inflammatory lung disease.

Meiotic crossing over between nonhomologous chromosomes affects chromosome segregation in yeast

Meiotic recombination between artificial repeats positioned on nonhomologous chromosomes occurs efficiently in the yeast Saccharomyces cerevisiae. Both gene conversion and crossover events have been observed, with crossovers yielding reciprocal translocations. In the current study, 5.5-kb ura3 repeats positioned on chromosomes V and XV were used to examine the effect of ectopic recombination on meiotic chromosome segregation. Ura3 random spores were selected and gene conversion vs. crossover events were distinguished by Southern blot analysis. Approximately 15% of the crossover events between chromosomes V and XV were associated with missegregation of one of these chromosomes. The missegregation was manifest as hyperploid spores containing either both translocations plus a normal chromosome, or both normal chromosomes plus one of the translocations. In those cases where it could be analyzed, missegregation occurred at the first meiotic division. These data are discussed in terms of a model in which ectopic crossovers compete efficiently with normal allelic crossovers in directing meiotic chromosome segregation.

Expression of Aeromonas caviae bla genes in Escherichia coli

An isolate of Aeromonas caviae 035 carried a 55.5 kb self-transferable plasmid. Transfer of the plasmid to Escherichia coli K12 resulted in the expression of a TEM-like beta-lactamase that was not expressed in parental A. caviae. The bla gene sequence was detectable by DNA hybridization and PCR amplification of the plasmid when extracted from parental A. caviae or from E. coli K12 transconjugants. Sequence analysis of the bla genes revealed in each case an 858 bp open reading frame, differing from the TEM-1 sequence by five nucleotide substitutions. Only one of these resulted in amino acid substitution (at position 162 serine-->arginine). The sequence most closely resembles that of TEM-12.

Protection from Shigella sonnei infection by immunisation of rabbits with Plesiomonas shigelloides (SVC 01)

Plesiomonas shigelloides, an organism commonly found in water, is only rarely associated with diarrhoea in man. P. shigelloides serotype O:17 (SVC O1), which is antigenically similar to Shigella sonnei, was found to be neither virulent nor toxic for rabbits. Rabbits immunised by feeding with P. shigelloides (SVC O1) were completely protected against an oral challenge with 10(10) cells of S. sonnei but non-immunised rabbits were not. P. shigelloides (SVC O1) may be a useful vaccine strain for shigellosis.

Occurrence of a large plasmid in a strain of Plesiomonas shigelloides with cross-reactivity against Shigella sonnei

The plasmid profile of P. shigelloides SVC 01, strain with cross-reactivity with Sh. sonnei, (obtained from Dr Alf Lindberg, Stockholm University, Sweden), was assayed and compared with other local isolates of Plesiomonas spp. and also with Sh. sonnei. Diversity in occurrence of plasmids among different strains of P. shigelloides were observed. Further, the SVC 01 strain and Sh. sonnei differ in their plasmid profile.