Carvacrol inhibits bacterial polysaccharide intracellular adhesin synthesis and biofilm formation of mucoid Staphylococcus aureus: an in vitro and in vivo study.

Staphylococcus aureus (S. aureus) is one of the important human pathogens and causes both superficial and systemic infections. More importantly, the formation of S. aureus biofilms, a main cause of its pathogenicity and drug resistance, has been a critical challenge in clinical treatment. Carvacrol, a plant-based natural product, has gained great interest for therapeutic purposes due to its effective biological activity with low cytotoxicity. The present study aimed to investigate the effect of carvacrol on anti-biofilm activity. Growth curve analysis showed that applying a sub-inhibitory concentration of carvacrol (4 µg mL-1) was not lethal to S. aureus SYN; however, the inhibition rate of biofilm formation was as high as 63.6%, and the clearance rate of mature biofilms was as high as 30.7%. In addition, carvacrol effectively reduced the production of biofilm-associated extracellular polysaccharides and showed no effect on eDNA release. Furthermore, qPCR analysis revealed that carvacrol significantly down-regulated the expression of icaA, icaB, icaC, agrA, and sarA (P < 0.05). The in vivo efficacy of carvacrol against biofilm infection was further verified with a biological model of G. mellonella larvae. The results showed that carvacrol was non-toxic to the larvae and can effectively increase the survival rate of the larvae infected with S. aureus strain SYN.

Identification and Characterization of a Vancomycin Intermediate-Resistant Staphylococcus haemolyticus Isolated from Guangzhou, China.

Background: Staphylococcus haemolyticus is an opportunistic pathogen that belongs to coagulase-negative Staphylococci (CoNS). Increasing infection and multi-drug resistance cases caused by this strain have been reported and thus it poses a great health threat. Methods: The third-generation sequencing technology was performed on a S. haemolyticus SH-1 isolated from a clinical sample to analyze the drug resistance genes, which included vancomycin resistance related genes. In addition, antimicrobial susceptibility tests, transmission electron microscopy and Triton X-100 stimulated autolysis were conducted to understand its biological characteristics. Results: The study shows that this clinical isolate is a vancomycin intermediate-resistant strain. Genome comparison also revealed that WalK(N70K) and WalK(R280Q) mutations may contribute to the vancomycin resistant phenotype. Besides, S. haemolyticus SH-1 exhibit common features of thicker cell wall and decreased autolytic activity. Conclusion: S. haemolyticus SH-1 with WalKR mutations shows typical characteristics of vancomycin resistant strains. Combining the genome features and biological properties, our findings may provide important information for the understanding of the molecular mechanism of S. haemolyticus to vancomycin intermediate-resistance.

MRI research of diaphragma sellae in patients with pituitary adenoma.

This study is to investigate the clinical significance of diaphragma sellae in patients with pituitary adenoma by MR images. A total of 47 cases of pituitary adenoma patients were enrolled in this study. Preoperative and postoperative MR scanning together with preoperative 3D-GE sequential scanning were performed. A series of parameters of diaphragma sellae were measured and compared. Tumor height was greater in patients with convex diaphragma sellae than that in patients with concave diaphragma sellae. The width and height of diaphragmal opening were positively related to tumor height. Diaphragmal opening width in the invasive group was greater than that of the non invasive group. Diaphragmal opening width in the non total resection group was significantly greater than that in the total resection group. Tumor resection rate was negatively correlated to diaphragmal opening width in the non total resection group. Lift angle of bilateral epidural around diaphragmal opening was positively related to tumor height. Enhanced 3D-GE images can perfectly display diaphragma sellae and parameters of tumor height and tumor invasiveness are related to diaphragmal opening diameter.

Relationship between pituitary adenoma texture and collagen content revealed by comparative study of MRI and pathology analysis.

This study is to reveal the relationship between pituitary adenomas and tumor texture by comparing MRI and pathologic results. Preoperative imaging data of 38 cases of pituitary adenoma patients and collagen content of tumor specimens measured by histopathological were analyzed and compared. T2WI and diffusion coefficient assessment were used to reveal the relationship between tumor texture and collagen content. There were 13 cases of soft texture, 17 cases of medium texture and 8 cases of tough texture tumors. Signal intensity of different texture Pituitary adenomas had significant difference on T2WI and ADC map (P < 0.05). The signal intensity ratio of tumor and pons on T2WI had high consistency with tumor texture. Mean collagen contents of soft, medium and tough texture group were 1.51% ± 0.91%, 7.35% ± 2.99% and 18.10% ± 8.24%, respectively. There were significant differences in collagen content of different texture tumors (P < 0.01). The signal intensity of T2WI and ADC images have prediction value for pituitary adenomas texture and T2WI is more reliable.

Analysis of operative efficacy for giant pituitary adenoma.

BACKGROUND: Surgical treatment of giant pituitary adenomas is difficult due to complicated dissection of the sellar area. The extent of tumor resection affects the efficacy of surgical treatment. This study is to investigate the efficacy of microsurgical treatment for giant pituitary adenoma and to analyze the relationship between treatment efficacy and tumor resection extent. METHODS: A retrospective analysis was performed in 36 patients who received microsurgery to remove giant pituitary adenomas. The sizes of tumors before and after surgery were calculated with a novel method called the "platform-like volume calculation formula". The relationships between extent of resection and the visual impairment recovery, and improvement of serum hormone level before and after operation were analyzed. RESULTS: Two deaths were observed after surgery. And the gross and near-total resection was achieved in 8 cases, subtotal resection in 8 cases, mostly partial resection in 15 cases, and partial resection in 5 cases. The average resection rate was 72.8%. The resection rate of tumor with cavernous sinus invasion was significantly lower than those of patients without cavernous sinus invasion (P < 0.05). The improvement rate of hormone level in functional adenoma was 80.0%. Follow-up observations were carried out for 3 ~ 28 months in 25 cases. Visual improvement was observed in 64.0% of the cases. CONCLUSIONS: Microsurgical treatment can improve the visual impairment of the majority of cases and significantly decrease the serum hormone levels of functional adenoma. The extent of resection was significantly associated with cavernous sinus invasion.

Racemization of (S)-profen thioesters by strong neutral bases in nonpolar organic solvents: implication for ion-pair kinetic basicity.

The racemization of (S)-profen 2,2,2-trifluoroethyl thioesters in isooctane with trioctylamine as base was carried out, in which the Hammett equation log(k(int)) = 3.584sigma - 3.745 was successfully applied to describe the electron-withdrawing effect of the substituents to the alpha-phenyl moiety of the thioesters. A combination of neutral strong organic bases with different nonpolar solvents was employed to determine the second-order interconversion constants for the racemization of (S)-naproxen 2,2,2-trifluoroethyl thioester, in which solvent hydrophobicity was found to have less effect on the racemization. Implication for ion-pair kinetic basicity scale for the neutral strong bases in isooctane was further discussed.