Melittin exhibits high antibacterial potency against drug-resistant bacteria. However, the clinical utility of melittin is limited by its serious hemolytic activity. Thus, the need for developing novel melittin analogues with high antimicrobial activity and low hemolytic activity has grown. We designed, synthesized, and evaluated 20 novel melittin analogues with varying hydrophobic, polar or positively charged amino acids. The results showed that 8 compounds had antimicrobial activity (MIC: 1-4 μg·mL^-1) against gram-positive pathogens equal to or better than that of melittin, and 16 compounds had low hemolytic activity (HC₅₀ ≥ 11.9 μg·mL^-1). Compounds 13 (MIC: 2-4 μg·mL^-1) and 15 (MIC: 1-2 μg·mL^-1) showed equal or better antimicrobial activity against both susceptible and resistant strains of Staphylococcus aureus and Enterococcus faecium compared to melittin (MIC: 4 μg·mL^-1). Compound 13 (HC₅₀: 24.0 ± 4.3 μg·mL^-1) displayed noticeably decreased hemolytic activity compared to melittin (HC₅₀: 5.3 ± 0.4 μg·mL^-1). This work established a base for further study on the structure-activity relationships and structure-toxicity relationships of melittin.

Aim To investigate the effect of broneol on acute lung injury(ALI) induced by lipopolysaccharide (LPS). Methods Male C57 mice were randomly di-vided into saline group, model group, broneol group and dexamethasone group, then the ALI mouse model was induced by instilling intratracheally with LPS. The levels of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),interleukin-6(IL-6) and keratinocyte-de-rived cytokine (KC) were measured at 6h, 12h and 24h after instillation of LPS, and the pathological changes of lung were observed. Mice alveolar macro-phages (MHS) and epithelial cells (MLE-12) were stimulated by LPS. After the stimulation of 1h, 3h, 6h,9h, 12h, 24h, the levels of TNF-α and IL-6 in MHS cells and the contents of KC and macrophage in-flammatory protein-2 (MIP-2) in MLE-12 cells were measured. Results Broneol could inhibit the secre-tion of TNF-α,KC and IL-1β;the early effect of bro-neol on IL-6 was not obvious,but the later effect after the treatment of 24 hours was obvious. After LPS instil-lation 6h and 12h,Broneol could significantly improve lung tissue pathological changes. Broneol had no effect on TNF-α secretion of MHS cells, but it obviously af-fected IL-6 secretion in the later stage. In addition, broneol significantly inhibited KC and MIP2 secretion in MLE-12 cells at the later stage of LPS stimulation. Conclusions Broneol can protect LPS-induced acute lung injury. The mechanism may be related to the inhi-bition of the release of inflammatory factors,the activa-tion of inflammatory cells and the aggregation of neutro-phils.

OBJECTIVETo study the morphological features of the lungs obtained from autopsies of severe acute respiratory syndrome (SARS) patients.

METHODSBilateral lungs from 7 patients died from SARS were carefully studied grossly and microscopically. All tissues from these cases were routinely processed and carefully studied.

RESULTSAll lungs from these cases were extremely expanded and became solid. Microscopically, the edema and fibrin exudates in the alveoli was the most common findings, especially in the early phase of the disease. The hyaline membrane was almost always present in the lungs of these cases. The organization of intra-alveolar fibrin exudates along with the interstitial fibrosis led to obliteration of alveoli and consolidation of lungs. The desquamation and hyperplasia of alveolar lining cells was also apparent. Foci of haemorrhage and lobular pneumonia, even diffuse fungal infection were frequently seen in these specimens. Micro-thrombus were easily found in these lungs.

CONCLUSIONSThe lung of SARS from autopsy is characterized by edema, intra-alveolar fibrin exudates, hyaline membrane formation, organization of intra-alveolar exudates and fibrosis, which lead to the obliteration of alveoli and consolidation of lungs.

Adult ; Female ; Humans ; Lung ; pathology ; Male ; Middle Aged ; Pulmonary Fibrosis ; pathology ; Severe Acute Respiratory Syndrome ; pathology

OBJECTIVESeven cases of autopsy from SARS patients are studied to investigate the pathogenesis and the pathologic changes of the major organs.

METHODSDetailed gross and microscopic examination of the autopsy specimen is performed, including lung, heart, liver, kidney, spleen and lymph nodes.

RESULTSAll of the lungs are markedly enlarged and consolidated. Microscopically, pulmonary edema is a prominent finding, especially at the early stage of the disease (5 days after the onset). The alveolar spaces are filled with fibrinous exudates and lined with hyaline membrane. In 5 cases that undergo over 3 weeks of the course, the main pattern is organization of intra-alveolar deposit, along with fibroblastic proliferation in the alveolar septa, which leads to obliteration of alveolar space and pulmonary fibrosis. All of the lungs show bronchopneumonia, scattered hemorrhage, and proliferation of alveolar epithelial cells with desquamation. Microthrombi are seen in 6 cases. Fungal infection is noted in 2 cases. One of them is disseminative, involving bilateral lungs, heart, and kidney; the other one is diagnosed in hilar lymph nodes. In immune system, hilar and abdominal lymph nodes are usually congested and hemorrhagic, with depletion of lymphocytes, and accompanied with subcapsular sinus histiocytosis. One of the cases shows enlargement of abdominal lymph nodes, which have reduced number of germinal centers. Spleen exhibits atrophy of white pulps, and even lost of white pulps in some areas. The red pulp is markedly congested and hemorrhagic. In 5 cases, cardiomegale is prominent. Thrombosis (2 cases), focal myocarditis (1 case), and fungal myocarditis (1 case) are observed. In addition, liver shows massive necrosis (1 case) and nodular cirrhosis (1 case).

CONCLUSIONSLung is the major organ affected by SARS, demonstrated as diffuse alveolar damage. It is postulated that viral infection induces severe damage of alveolar epithelial and capillary endothelial cells, leads to pulmonary edema, intra-alveolar fibrin deposit, and hyaline membrane formation. Consequently, intra-alveolar organization and alveolar septal fibrosis causes loss of alveolar spaces, eventually, pulmonary fibrosis and atelectasis. The immune system is often affected, and presented as depletion of lymphoid tissue in lymph nodes and spleen. Secondary infection is a common complication, which should be paid close attention in the management of SARS patients.

Adrenal Glands ; pathology ; Adult ; Autopsy ; Bone Marrow ; pathology ; Female ; Humans ; Kidney ; pathology ; Liver ; pathology ; Lung ; pathology ; Male ; Middle Aged ; Myocardium ; pathology ; Severe Acute Respiratory Syndrome ; pathology ; Spleen ; pathology

Daphnetin is quickly eliminated in rats after dosing, but the mechanism remains unclear. This study was aimed to investigate the in vitro metabolism of daphnetin using rat liver S9 fractions (RLS9). The metabolites formed in RLS9 were identified and the kinetic parameters for different metabolic pathways were determined. HPLC-DAD-MS analysis showed that daphnetin was biotransformed to six metabolites, which were identified as 7 or 8 mono-glucuronide and mono-sulfate, 8-methylate, and 7-suflo-8-methylate. Methylation and glucuronidation of daphnetin exhibited the Michaelis-Menten kinetic characteristics, whereas the substrate inhibition kinetic and the two-site kinetic were observed for 8-sulfate and 7-sulfate formations. Of the 3 conjugation pathways, the intrinsic clearance rate for sulfation was highest, followed by methylation and glucuronidation. By in vitro-in vivo extrapolation of the kinetic data measured in RLS9, the hepatic clearance were estimated to be 54.9 mL·min^-1·kg^-1 which is comparable to the system clearance (58.5 mL·min^-1·kg^-1) observed in rats. In conclusions, the liver might be the main site for daphnetin metabolism in rats. Sulfation, methylation and glucuronidation are important pathways of the hepatic metabolism of daphnetin in rats.