Levofloxacin-ceftazidime administration regimens combat Pseudomonas aeruginosa in the hollow-fiber infection model simulating abnormal renal function in critically ill patients

BACKGROUND

The purpose of this study was to investigate the bactericidal effects of levofloxacin and ceftazidime as both monotherapy and combination therapy, and to determine their effects on resistance suppression in patients with normal and abnormal (Ccr:16-20 mL/min) renal function. Common clinical administration regimens to provide reference values were further evaluated.

METHODS

The 7-d hollow-fiber infection model was used to inject the Pseudomonas aeruginosa standard strain (ATCC27853), which simulated common clinical administration regimens for patients with different renal function. Ten regimens were stratified into 2 categories based on renal function, and each category contained 3 monotherapy regimens and 2 combination therapy regimens. Total and resistant populations were quantified. Drug concentrations were determined by high-performance liquid chromatography (HPLC).

RESULTS

Monotherapy regimens resulted in about 0.5-log-CFU/mL bacterial kill in the total population at 6 or 8 h, whilst combination regimens resulted in 2- to 3-log-CFU/mL within 2 days. For levofloxacin monotherapy regimens in patients with normal renal function, resistance emergence was seen after 6 h, and was seen at 0 h in the ceftazidime monotherapy regimen, as well as in all regimens of patients with abnormal renal function. Although resistant subpopulation in combination regimens with abnormal renal function began to increase at 0 h, there was a definite downward trend after 8 h, while resistant population in the normal renal function group increased after 16 h.

CONCLUSIONS

Combination therapy had greater bactericidal efficacy and resistance inhibition compared with monotherapy. Studying combination regimens in randomized clinical trials is warranted.

Isolation of swine-derived Lactobacillus plantarum and its synergistic antimicrobial and health-promoting properties with ZnO nanoparticles

AIMS

The purpose of this study was to isolate Lactobacillus from gastrointestinal tract of healthy postweaning piglets and investigate its synergistic antimicrobial and probiotic effects with ZnO nanoparticles (nZnO).

METHODS AND RESULTS

Of the 128 isolates, Lactobacillus plantarum BLPL03 was selected based on its excellent acid and bile salt tolerance properties. Lactobacillus plantarum BLPL03 was sensitive to β-lactams, macrolides, amphenicols and cephalosporins, whereas it displayed the steady resistance to aminoglycosides, tetracyclines, quinolones and peptide antibiotics. In vitro analysis of antibacterial activities showed that L. plantarum BLPL03 inhibited the four common food-borne pathogenic bacteria including Escherichia coli O157:H7 CMCC 44828, Salmonella Typhimurium ATCC 13311, Staphylococcus aureus CMCC 26003 and Listeria monocytogenes CMCC 54007 in synergy with nZnO. Furthermore, the quantitative polymerase chain reaction test demonstrated that the combined administration of L. plantarum BLPL03 fermentation liquor (LFL) and nZnO synergistically elevated the faecal number of Bifidobacterium by 73·19-fold, and reduced the two potential enteropathogenic bacteria Enterobacteriaceae and Clostridium perfringens in mice challenged with Salm. Typhimurium. Finally, dietary supplementation with low dose of nZnO (20 mg kg^-1 ) when combined with LFL administration enhanced final body weight, fur appearance and average daily gain, and decreased feed conversion ratio and diarrhoea incidence in weaned piglets. The faecal Bifidobacterium and Lactobacillus of piglets were dramatically enhanced by 81·96- and 3·15-fold, respectively, after administration of a mixture of nZnO and LFL. Meanwhile, combination of nZnO with LFL resulted in low levels of Bacteroides, Enterococcus, and Enterobacteriaceae.

CONCLUSIONS

A combination of nZnO and LFL exhibits potential health-benefit properties for the control of gut microbial composition by their synergistic antimicrobial and probiotic effects.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study may provide a potential nutritional strategy to improve performance and gut health of animals with gut microbiota disorders caused by pathogen infections and weanling, and so on.

Geometry, induced magnetism and modified electronic behaviors for magnetic atom adsorption on antimonene nanotubes

The detailed first-principles calculations show that TM adsorption can imprint versatile magnetism into antimonene nanotubes. A significant carrier polarity and spin polarity of mobility as well as the magneto-electric material property are found.

Psychometric assessment and application of the Chinese version of the Compliance with Annual Diabetic Eye Exams Survey in people with diabetic retinopathy

AIM

To translate the Compliance with Annual Diabetic Eye Exams Survey (CADEES) into Chinese, allowing assessment of its reliability and validity, and to identify variables that predict attendance at annual eye examinations.

METHODS

People with vision-threatening diabetic retinopathy were recruited from the Shanghai Diabetic Eye Study. The study involved three phases: (1) translation and cross-cultural adaptation, (2) a pilot study (n = 496) to evaluate the psychometric properties of the Chinese-CADEES, and (3) a primary cross-sectional survey (n = 3818) to assess self-reported attendance at annual eye examinations. Factors related to non-attendance were identified using univariate analysis, and then a multiple logistic regression model. Finally, a component model and individual item models were built to predict attendance.

RESULTS

The Chinese-CADEES had satisfactory reliability and validity. The issue of low attendance at annual eye examinations was serious. In addition to 13 health belief items, living in semi-urban suburban areas, shorter duration of diabetes, poor glucose control, lower education level, better presenting visual acuity and milder diabetic retinopathy diagnosis were significantly related to non-attendance. The multivariate predictive model was able to predict, with 64.7% accuracy, whether or not participants were going to attend annual eye examinations and explained ~ 11.3% of the variance in attendance.

CONCLUSIONS

The Chinese-CADEES showed good reliability and validity for predicting attendance at annual eye examinations in people with diabetic retinopathy. Clinicians and researchers can improve attendance by addressing modifiable characteristics and increasing education on diabetic retinopathy and the importance of eye health in people with diabetes.

Autophagy triggered by MAVS inhibits Coxsackievirus A16 replication

Mitochondrial antiviral signaling protein (MAVS), a crucial adaptor protein localized on mitochondria, plays vital roles in various biological processes. Autophagy and apoptosis are two independent and closely linked cell death pathways. But whether MAVS could induce apoptosis and autophagy in rhabdomyosarcoma cells (RD cells) and what is the relationship between autophagy and apoptosis still remains elusive. Here, we reveal that overexpression of MAVS could trigger both apoptosis and autophagy in RD cells. Interestingly, MAVS-induced apoptosis was dependent on the activation of the c-Jun N-terminal kinase (JNK) signaling pathway and inhibition of the extracellular signal-regulated kinase (ERK) signaling pathway. Also, it was found that inhibition of autophagy by 3-methyladenine (3-MA) enhanced MAVS-induced apoptosis resulting in increased cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP). Meanwhile, autophagy induction by rapamycin resulted in decreased MAVS-induced apoptosis. In addition, we found that MAVS expression was inhibited upon Coxsackievirus A16 (CA16) infection and overexpression of MAVS could inhibit CA16 replication. Collectively, our study provides novel insights into the link between apoptosis and autophagy induced by MAVS overexpression in RD cells and gains a greater understanding of MAVS-induced antiviral functions, which provide new targets for CA16 treatment. Keywords: CA16; MAVS; apoptosis; autophagy.

Effect of hypoxia on the Twist1 in EMT of cervical cancer cells

OBJECTIVE

To explore the effect of hypoxia on the Twist1 expression in epithelial-mesenchymal transition of the cervical cancer cells.

MATERIALS AND METHODS

In this study, we simulated the normoxia and hypoxia environment, where HeLa cells were cultured, respectively. Cell invasion ability was measured by the transwell assay, while the GLI-1 protein and mRNA expressions were measured by Real-time polymerase chain reaction (RT-PCR) and Western blot assays. After that, HeLa cells were transfected with the GLI-1-specific siRNA, followed by the measurement of mRNA and protein expressions using RT-PCR and Western blot assays, as well as the cell invasion ability by the transwell assay.

RESULTS

We found that in hypoxic environment, GLI-1 was up-regulated in HeLa cells, with enhanced invasion ability. However, silencing the expression of GLI-1 could reverse the up-regulation of GLI-1 compromising the invasion ability of HeLa cells.

CONCLUSIONS

Hypoxia may account for the increased invasion of HeLa cells, which is realized by the up-regulated GLI-1.

[Short-term outcomes and prognosis of palliative surgery for malignant bowel obstruction caused by peritoneal metastasis of colorectal cancer]

Objective: To explore the short-term efficacy and prognosis of palliative surgical treatment for malignant bowel obstruction (MBO) caused by peritoneal metastasis of colorectal cancer (mCRC). Methods: A retrospective cohort study was conducted. The inclusion criteria for patients were as follows: (1) primary colorectal cancer; (2) massive peritoneal metastasis; (3)obstructive site located below Treitz ligament by imaging; (4) obstruction refractory to conservative treatment; (5) estimated rese survival time more than 2 months; (6) patients and their families had strong willingness for operation; (7) surgical treatment included stoma/bypass and debulking surgery. In accordance with the above criteria, clinicopathological data of 46 patients undergoing palliative surgery at Peking University Gastrointestinal Cancer Center, Unit III from January 2016 to October 2018 were retrospectively collected. Postoperative symptomatic relief rate, morbidity of complication within 30 days, complication classification (Clavien-Dindo classification), mortality and survival after operation were analyzed. Kaplan-Meier method was used to evaluate survival and Cox regression analysis was used to identify prognostic factors. Results: Among 46 patients, 30 were male and 16 were female with median age of 63 (19-87) years; 23 patients received stoma/bypass surgery (stoma/bypass group), and 23 cases received tumor debulking surgery (debulking group). The overall symptom relief rate was 76.1% (35/46), while symptom relief rate in the debulking group was 91.3% (21/23), which was significantly higher than 60.9% (14/23) in the stoma/bypass group (χ(2)=4.301, P=0.038). Postoperative complications occurred in 25 patients. The complication rate was 52.2% (12/23) in the debulking group and 56.5% (13/23) in the stoma/bypass group, without statistically significant difference (χ(2)=0.088, P=0.767). Morbidity of complication beyond grade III was 8.7% (2/23) and 13.0% (3/23) in the debulking group and stoma/bypass group respectively, without statistically significant difference (χ(2)=0.224, P=0.636). Four patients died within 30 days after operation, 2 (8.7%) in each group. Twenty-four patients underwent 1-8 cycles of chemotherapy ± targeting therapy (regimens: CapeOX ± Bevacizumab, FOLFOX/FOLFIRI ± Bevacizumab/Cetuximab), including 10 cases in the stoma/bypass group and 14 cases in the debulking group. Two patients of debulking group received postoperative radiotherapy and chemotherapy (50.6 Gy/22 f, with concurrent oral capecitabine). Till the last follow up of April 2019, 34 patients died (34/46, 73.9%) with a median overall survival time of 6.4 months, and the 6-month and 1-year survival rate was 54.5% and 29.2% respectively. The median survival time in the debulking group was significantly longer than that in the stoma/bypass group (11.5 months vs. 5.2 months, χ(2)=5.117, P=0.024). The median survival time of the 35 patients with symptomatic relief after operation was significant longer than that of 11 patients without relief (7.1 months vs 5.1 months, χ(2)=3.844, P=0.050). Multivariate analysis showed stoma/bypass surgery (HR=2.917, 95%CI:1.357-6.269, P=0.006) and greater omental metastasis (HR=4.060, 95%CI:1.419-11.617, P=0.009) were independent risk factors associated with prognosis of patients with MBO caused by peritoneal mCRC. Conclusions: For patients of MBO caused by peritoneal mCRC, tumor debulking surgery may achieve higher symptom relief rate and prolong survival. Greater omental metastasis indicates poor prognosis.

[Stent placement for filter-related chronic occlusion of the inferior vena cava]

Objective: To assess the technical success rate, stent patency, clinical efficacy and complications of stent placement for filter-related chronic occlusion of the inferior vena cava. Methods: A retrospective analysis was carried out for 12 patients with filter-related chronic occlusion of the inferior vena cava associated with severe post-thrombotic syndrome, who underwent stent placement after ineffective conservative therapy at Nanjing First Hospital from March 2016 to December 2018,9 males and 3 females, aged from 48 to 77 years, mean age 60 years, six had bilateral lower extremity symptoms and six had unilateral lower extremity symptoms.Technical success rate, stent patency, clinical efficacy and complications of stent placement were recorded. Clinical success was defined as relief of symptoms and a decrease in clinical, etiology, anatomy, and pathophysiology (CEAP) score for at least grade 1. Results: Stent placement in the unilateral or bilateral iliocaval occlusion was successful in 11 patients. The cause of technical failure in the single patient with failed stent placement was an inability to cross the occluded left iliacvein and the patient was treated with stent placement in the right iliocaval vein.There were 7 patients with inferior vena cava and unilateral iliocaval stent placement; 5 patients with inferior vena cava and bilateral iliocaval stent placement. Acute stent thrombosis occlusion occurred in 1 case after the operation, the blood flow recanalized after catheter-directed thrombolysis and re-stenting. All patients were followed up for 6 to 24 months, with an average of (13±6) months. During the follow-up period, CTV or venography of lower limbs showed that the blood flow in the stent was unobstructed. At the last follow-up, 12 patients were evaluated as clinically effective. Three patients had transient treatment of lateral lumbar pain during operation, which alleviated by themselves.No significant abdominal pain, severe hemorrhage, symptomatic pulmonary embolism and other complications related to treatment occurred in all patients during perioperative period and follow-up. Conclusion: Stent placement is safe and feasible in the treatment of filter-related chronic occlusion of the inferior vena cava, which can alleviate the clinical symptoms of severe post-thrombotic syndrome.

Intraspinal Paragonimiasis in Children: MRI Findings and Suggestions for Pathogenesis

BACKGROUND AND PURPOSE

Intraspinal paragonimiasis is a rare entity for which imaging findings have seldom been described. The present study investigated the MR imaging features of spinal paragonimiasis, thus providing diagnostic imaging evidence and exploring the possible pathogenesis of intraspinal paragonimiasis.

MATERIALS AND METHODS

The clinical and imaging findings of spinal paragonimiasis in 6 children were analyzed retrospectively. Spinal MR imaging was performed in all patients, 5 of whom also underwent enhanced MR imaging. The diagnosis was confirmed by enzyme-linked immunosorbent assay in all cases and postoperative pathology in 4 cases.

RESULTS

All cases manifested as fusiform-shaped or beanlike masses in the extradural space in the thoracic spine. The extradural masses were connected with pleural lesions through the intervertebral foramen. The plain MR imaging scan showed mixed signals with predominant isointensity on T1WI and hyperintensity on T2WI, among which 5 (5/6) masses presented as patchy hemorrhage with hyperintensity on T1WI. On enhanced scans, all masses (5/5) showed heterogeneous marked enhancement, with thickening and enhancement in the adjacent spinal meninges (5/5). Various degrees of spinal cord compression and edema were found in 5 cases (5/6).

CONCLUSIONS

MR imaging is sensitive for detecting and characterizing spinal paragonimiasis. The MR imaging features of intraspinal granulomas included localization to the extradural space and thoracic segment, connections between intraspinal lesions and pleural lesions through the intervertebral foramen, and hemorrhagic foci within the mass. These findings support an intraspinal mode of paragonimiasis pathogenesis: The Paragonimus larvae migrate from the chest into the extradural space through the intervertebral foramen.

Precision Reengineering of the Oral Microbiome for Caries Management

Technological advancements have revolutionized our understanding of the complexity and importance of the human microbiome. This progress has also emphasized the need for precision therapeutics, as it has underscored the dilemmas, such as dysbiosis and increasing antibiotic resistance, associated with current, broad-spectrum treatment modalities. Dental caries remains the most common chronic disease worldwide, accompanied by a tremendous financial and social burden, despite widespread and efficacious fluoride and hygienic regimens. Over the past several decades, various precision approaches to combat dental caries, including vaccines, probiotics, and antimicrobial compounds, have been pursued. Despite the distinct overall conceptual strengths of each approach, for various reasons, there are currently no approved precision antibiotic therapeutics to prevent dental caries. Specifically targeted antimicrobial peptides (STAMPs) are synthetic molecules that combine the antibiotic moiety of a traditional antimicrobial peptide with a targeting domain to provide specificity against a particular organism. Conjoining the killing domain from the antimicrobial, novispirin G10, and a targeting domain derived from the Streptococcus mutans pheromone, CSP, the STAMP C16G2 was designed to provide targeted killing of S. mutans, widely considered the keystone species in dental caries pathogenesis. C16G2 was able to selectively eliminate S. mutans from complex ecosystems while leaving closely related, yet health-associated, oral species unharmed. This remodeling of the dental plaque community is expected to have significant advantages compared to conventional broad-spectrum mouthwashes, as the intact, surviving community is apt to prevent reinfection by pathogens. Following successful phase I clinical trials that evaluated the safety and basic microbiology of C16G2 treatments, the phase II trials of several C16G2 formulations are currently in progress. C16G2 represents an exciting advance in precision therapeutics, and the STAMP platform provides vast opportunities for both the development of additional therapeutics and the overall study of microbial ecology.

Afatinib versus methotrexate as second-line treatment in Asian patients with recurrent or metastatic squamous cell carcinoma of the head and neck progressing on or after platinum-based therapy (LUX-Head & Neck 3): an open-label, randomised phase III trial

BACKGROUND

Treatment options are limited for patients with recurrent or metastatic squamous cell carcinoma of the head and neck (HNSCC) following progression after first-line platinum-based therapy, particularly in Asian countries.

PATIENTS AND METHODS

In this randomised, open-label, phase III trial, we enrolled Asian patients aged ≥18 years, with histologically or cytologically confirmed recurrent/metastatic HNSCC following first-line platinum-based therapy who were not amenable for salvage surgery or radiotherapy, and had an Eastern Cooperative Oncology Group (ECOG) performance status of 0/1. Patients were randomised (2 : 1) to receive oral afatinib (40 mg/day) or intravenous methotrexate (40 mg/m2/week), stratified by ECOG performance status and prior EGFR-targeted antibody therapy. The primary end point was progression-free survival (PFS) assessed by an independent central review committee blinded to treatment allocation.

RESULTS

A total of 340 patients were randomised (228 afatinib; 112 methotrexate). After a median follow-up of 6.4 months, afatinib significantly decreased the risk of progression/death by 37% versus methotrexate (hazard ratio 0.63; 95% confidence interval 0.48-0.82; P = 0.0005; median 2.9 versus 2.6 months; landmark analysis at 12 and 24 weeks, 58% versus 41%, 21% versus 9%). Improved PFS was complemented by quality of life benefits. Objective response rate was 28% with afatinib and 13% with methotrexate. There was no significant difference in overall survival. The most common grade ≥3 drug-related adverse events were rash/acne (4% with afatinib versus 0% with methotrexate), diarrhoea (4% versus 0%), fatigue (1% versus 5%), anaemia (<1% versus 5%) and leukopenia (0% versus 5%).

CONCLUSIONS

Consistent with the phase III LUX-Head & Neck 1 trial, afatinib significantly improved PFS versus methotrexate, with a manageable safety profile. These results demonstrate the efficacy and feasibility of afatinib as a second-line treatment option for certain patients with recurrent or metastatic HNSCC.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01856478.

Smart identification of psoriasis by images using convolutional neural networks: a case study in China

BACKGROUND

Psoriasis is a chronic inflammatory skin disease, which holds a high incidence in China. However, professional dermatologists who can diagnose psoriasis early and correctly are insufficient in China, especially in the rural areas. A smart approach to identify psoriasis by pictures would be highly adaptable countrywide and could play a useful role in early diagnosis and regular treatment of psoriasis.

OBJECTIVES

Design and evaluation of a smart psoriasis identification system based on clinical images (without relying on a dermatoscope) that works effectively similar to a dermatologist.

METHODS

A set of deep learning models using convolutional neural networks (CNNs) was explored and compared in the system for automatic identification of psoriasis. The work was carried out on a standardized dermatological dataset with 8021 clinical images of 9 common disorders including psoriasis along with full electronic medical records of patients built over the last 9 years in China. A two-stage deep neural network was designed and developed to identify psoriasis. In the first stage, a multilabel classifier was trained to learn the visual patterns for each individual skin disease. In the second stage, the output of the first stage was utilized to distinguish psoriasis from other skin diseases.

RESULTS

The area under the curve (AUC) of the two-stage model reached 0.981 ± 0.015, which outperforms a single-stage model. And, the classifier showed superior performance (missed diagnosis rate: 0.03, misdiagnosis rate: 0.04) than 25 Chinese dermatologists (missed diagnosis rate: 0.19, misdiagnosis rate: 0.10) in the diagnosis of psoriasis on 100 clinical images.

CONCLUSIONS

Using clinical images to identify psoriasis is feasible and effective based on CNNs, which also builds a solid technical base for smart care of skin diseases especially psoriasis using mobile/tablet applications for teledermatology in China.

Normal fertility with deletion of sY84 and sY86 in AZFa region

BACKGROUND

Entire deletion of the azoospermia factor a (AZFa) region commonly results in non-obstructive-azoospermia (NOA). Although sY84 and sY86 are recommended as the first choice of sequence-tagged sites (STSs) primers in AZFa region, and their deletions suggest a very high probability of complete deletion of AZFa, extension analysis is now compulsory to identify the deletion pattern.

OBJECTIVES

We aim to verify that extension analysis is relevant in assessing the deletion pattern of AZF by reporting a family in which two normal fertile men were confirmed to have a deletion of sY84 and sY86.

MATERIALS AND METHODS

According to the EAA/EMQN recommendation, AZF evaluation was detected by multiplex polymerase chain reaction (PCR) with six STSs, and extension analysis was performed to identify the deletion pattern due to the deletions of sY84 and sY86. And the further exploration was conducted to map the breakpoints of deleted DNA fragment.

RESULTS

Deletion of sY84 and sY86 was found in the case with coinstantaneous normal semen analysis. An identically partial deletion pattern of AZFa region with the absence of an hg38Y fragment (12470437~12690385, 219949 bp in total) was found in both the case and his father, which includes three pseudogenes and one non-coding-RNA gene.

DISCUSSION AND CONCLUSION

The extension analysis has permitted the diagnosis of a partial AZFa deletion and confirmed the importance of the extension analysis in order to provide a more accurate prediction for the testis phenotype.

Nuclear Dependence of the Transverse Single-Spin Asymmetry in the Production of Charged Hadrons at Forward Rapidity in Polarized p+p, p+Al, and p+Au Collisions at sqrt[s_{NN}]=200 GeV

We report on the nuclear dependence of transverse single-spin asymmetries (TSSAs) in the production of positively charged hadrons in polarized p^{↑}+p, p^{↑}+Al, and p^{↑}+Au collisions at sqrt[s_{NN}]=200  GeV. The measurements have been performed at forward rapidity (1.4<η<2.4) over the range of transverse momentum (1.8<p_{T}<7.0  GeV/c) and Feynman x (0.1<x_{F}<0.2). We observed positive asymmetries for positively charged hadrons in p^{↑}+p collisions, and significantly reduced asymmetries in p^{↑}+A collisions. These results reveal a nuclear dependence of TSSAs for charged-hadron production in a regime where perturbative techniques are applicable. These results provide new opportunities to use p^{↑}+A collisions as a tool to investigate the rich phenomena behind TSSAs in hadronic collisions and to use TSSAs as a new handle in studying small-system collisions.

A new method for detecting thermal characteristics of slow-wave structure of helix traveling-wave tube using external heat source

This paper presents a method for detecting the heat-dissipation capability of the slow-wave structure (SWS) in a helix traveling wave tube (TWT) using an external heat source. This method utilizes transient temperature rise detection technology and structure function method to nondestructively detect the heat-dissipation capability of SWS. An analytical model is built, and the method is verified by using the simulation tool ANSYS. Furthermore, a dedicated test probe is designed based on this method, and a 2.5-mm diameter helix TWT is measured. The results reveal that the method can effectively detect parts with large thermal resistance in SWS, thereby providing the basis for eliminating the failure products and improving the production process of SWS.

Revealing interfacial disorder at the growth-front of thick many-layer epitaxial graphene on SiC: a complementary neutron and X-ray scattering investigation

Epitaxial graphene on SiC provides both an excellent source of high-quality graphene as well as an architecture to support its application. Although single-layer graphene on Si-face SiC has garnered extensive interest, many-layer graphene produced on C-face SiC could be significantly more robust for enabling applications. Little is known, however, about the structural properties related to the growth evolution at the buried interface for thick many-layer graphene. Using complementary X-ray scattering and neutron reflectivity as well as electron microscopy, we demonstrate that thick many-layer epitaxial graphene exhibits two vastly different length-scales of the buried interface roughness as a consequence of the Si sublimation that produces the graphene. Over long lateral length-scales the roughness is extremely large (hundreds of Å) and it varies proportionally to the number of graphene layers. In contrast, over much shorter lateral length-scales we observe an atomically abrupt interface with SiC terraces. Graphene near the buried interface exhibits a slightly expanded interlayer spacing (∼1%) and fluctuations of this spacing, indicating a tendency for disorder near the growth front. Nevertheless, Dirac cones are observed from the graphene while its domain size routinely reaches micron length-scales, indicating the persistence of high-quality graphene beginning just a short distance away from the buried interface. Discovering and reconciling the different length-scales of roughness by reflectivity was complicated by strong diffuse scattering and we provide a detailed discussion of how these difficulties were resolved. The insight from this analysis will be useful for other highly rough interfaces among broad classes of thin-film materials.