[Analysis of clinical characteristics and risk factors of death in critical burn patients complicated with invasive fungal infection].

Objective: To investigate the clinical characteristics and risk factors of critical burn patients complicated with invasive fungal infection. Methods: A retrospective case series study was conducted. From January 2017 to December 2022, 88 critical burn patients combined with invasive fungal infection who met the inclusion criteria were admitted to Zhengzhou First People's Hospital, including 61 males and 27 females, aged 26-74 years. Data on invasive fungal infection sites and the detection of pathogens in patients were recorded. According to the survival outcome within 28 days after admission, the patients were divided into survival group (63 cases) and death group (25 cases). The following data of patients were compared between the two groups, including the basic data and injuries of patients at admission such as age, sex, body weight, total burn area, combination of inhalation injury, combination of hypertension and diabetes, acute physiology and chronic health status evaluation Ⅱ (APACHE Ⅱ) score, and admission time after burns, the levels of blood biochemical indexes within 24 h after admission such as white blood cell count, platelet count, red blood cell count, monocyte count, neutrophil count, lymphocyte count, alanine transaminase, aspartate transaminase, glucose, creatinine, urea nitrogen, D-dimer, galactomannan (GM), 1,3-ß-D glucan, and creatine kinase, the application of invasive procedures and vasoactive drugs during the treatment such as continuous renal replacement therapy, ventilator-assisted breathing, tracheotomy, deep vein catheterization, skin grafting >2 times, the levels of infection indicators on post admission day (PAD) 1, 3, 7, and 14 including C-reactive protein (CRP), procalcitonin, lactic acid, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and the detection of pathogens in the process of treatment. Data were statistically analyzed with independent sample t test, analysis of variance for repeated measurement, chi-square test, Mann-Whitney U test, and Bonferroni correction. Multivariate logistic regression analysis was performed to screen the independent risk factors that affected death of critical burn patients complicated with invasive fungal infection. Results: The main sites of invasive fungal infection were the wounds (67 cases) and blood stream (46 cases), with Candida fungi (58 strains) as the main strain for fungi infection, and there were a total of 30 cases of infection with mixed pathogenic bacteria. Compared with those in survival group, the APACHE Ⅱ score, proportions of combination with inhalation injury and hypertension of patients in death group were significantly increased (t=2.11, with χ2 values of 6.26 and 9.48, respectively, P<0.05), while the other basic data and injury condition had no significant changes (P>0.05). Compared with those in survival group, the levels of D-dimer, GM, and 1,3-ß-D glucan of patients in death group were significantly increased within 24 h after admission (with t values of 2.42, 2.05, and 2.21, respectively, P<0.05), while the other blood biochemical indexes within 24 h after admission, as well as the proportions of applying invasive procedures and application of vasoactive drugs during the treatment process were not significantly changed (P>0.05). The levels of infection indicators of patients on PAD 1 and 3 were similar between the two groups (P>0.05). The procalcitonin level on PAD 7 and the levels of CRP, procalcitonin, lactic acid, IL-6, and TNF-α on PAD 14, as well as the proportion of infection with mixed pathogenic bacteria of patients in death group were significantly higher than those in survival group (with t values of 4.69, 3.89, 6.70, 6.14, 4.65, and 3.26, respectively, χ2=12.67, P<0.05). Multivariate logistic regression analysis showed that combination with inhalation injury, combination with hypertension, and infection with mixed pathogenic bacteria were independent risk factors for death of critical burn patients complicated with invasive fungal infection (with odds ratios of 5.98, 4.67, and 6.19, respectively, 95% confidence intervals of 1.42-15.39, 1.41-25.28, and 1.86-20.58, respectively, P<0.05). Conclusions: The main sites of infection in critical burn patients complicated with invasive fungal infection are the wounds and blood stream, with Candida fungi as the main strain for fungi infection, and a large proportion of infection with mixed pathogenic bacteria. The combined inhalation injury, combined hypertension, and infection with mixed pathogenic bacteria are the independent risk factors for the death of those patients.

[Value of cerebral hypoxic-ischemic injury markers in the early diagnosis of sepsis associated encephalopathy in burn patients with sepsis].

Objective: To explore the value of cerebral hypoxic-ischemic injury markers in the early diagnosis of sepsis associated encephalopathy (SAE) in burn patients with sepsis. Methods: A retrospective case series study was conducted. From October 2018 to May 2021, 41 burn patients with sepsis who were admitted to Zhengzhou First People's Hospital met the inclusion criteria, including 23 males and 18 females, aged 18-65 (35±3) years. According to whether SAE occurred during hospitalization, the patients were divided into SAE group (21 cases) and non-SAE group (20 cases). The gender, age, deep partial-thickness burn area, full-thickness burn area, and acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) scores of patients were compared between the two groups. The serum levels of central nervous system specific protein S100ß and neuron specific enolase (NSE) at 12, 24, and 48 h after sepsis diagnosis (hereinafter referred to as after diagnosis), the serum levels of interleukin-6 (IL-6), IL-10, tumor necrosis factor α (TNF-α), Tau protein, adrenocorticotropic hormone (ACTH), and cortisol at 12, 24, 48, 72, 120, and 168 h after diagnosis, and the mean blood flow velocity of middle cerebral artery (VmMCA), pulsatility index, and cerebral blood flow index (CBFi) on 1, 3, and 7 d after diagnosis of patients in the two groups were counted. Data were statistically analyzed with chi-square test, analysis of variance for repeated measurement, independent sample t test, and Bonferroni correction. The independent variables to predict the occurrence of SAE was screened by multi-factor logistic regression analysis. The receiver operating characteristic (ROC) curve was drawn for predicting the occurrence of SAE in burn patients with sepsis, and the area under the curve (AUC), the best threshold, and the sensitivity and specificity under the best threshold were calculated. Results: The gender, age, deep partial-thickness burn area, full-thickness burn area, and APACHE Ⅱ score of patients in the two groups were all similar (χ2=0.02, with t values of 0.71, 1.59, 0.91, and 1.07, respectively, P>0.05). At 12, 24, and 48 h after diagnosis, the serum levels of S100ß and NSE of patients in SAE group were all significantly higher than those in non-SAE group (with t values of 37.74, 77.84, 44.16, 22.51, 38.76, and 29.31, respectively, P<0.01). At 12, 24, 48, 72, 120, and 168 h after diagnosis, the serum levels of IL-10, Tau protein, and ACTH of patients in SAE group were all significantly higher than those in non-SAE group (with t values of 10.68, 13.50, 10.59, 8.09, 7.17, 4.71, 5.51, 3.20, 3.61, 3.58, 3.28, 4.21, 5.91, 5.66, 4.98, 4.69, 4.78, and 2.97, respectively, P<0.01). At 12, 24, 48, 72, and 120 h after diagnosis, the serum levels of IL-6 and TNF-α of patients in SAE group were all significantly higher than those in non-SAE group (with t values of 8.56, 7.32, 2.08, 2.53, 3.37, 4.44, 5.36, 5.35, 6.85, and 5.15, respectively, P<0.05 or P<0.01). At 12, 24, and 48 h after diagnosis, the serum level of cortisol of patients in SAE group was significantly higher than that in non-SAE group (with t values of 5.44, 5.46, and 3.55, respectively, P<0.01). On 1 d after diagnosis, the VmMCA and CBFi of patients in SAE group were significantly lower than those in non-SAE group (with t values of 2.94 and 2.67, respectively, P<0.05). On 1, 3, and 7 d after diagnosis, the pulsatile index of patients in SAE group was significantly higher than that in non-SAE group (with t values of 2.56, 3.20, and 3.12, respectively, P<0.05 or P<0.01). Serum IL-6 at 12 h after diagnosis, serum Tau protein at 24 h after diagnosis, serum ACTH at 24 h after diagnosis, and serum cortisol at 24 h after diagnosis were the independent risk factors for SAE complicated in burn patients with sepsis (with odds ratios of 2.42, 1.38, 4.29, and 4.19, 95% confidence interval of 1.76-3.82, 1.06-2.45, 1.37-6.68, and 3.32-8.79, respectively, P<0.01). For 41 burn patients with sepsis, the AUC of ROC of serum IL-6 at 12 h after diagnosis for predicting SAE was 0.92 (95% confidence interval was 0.84-1.00), the best threshold was 157 pg/mL, the sensitivity was 81%, and the specificity was 89%. The AUC of ROC of serum Tau protein at 24 h after diagnosis for predicting SAE was 0.92 (95% confidence interval was 0.82-1.00), the best threshold was 6.4 pg/mL, the sensitivity was 97%, and the specificity was 99%. The AUC of ROC of serum ACTH at 24 h after diagnosis for predicting SAE was 0.96 (95% confidence interval was 0.89-1.00), the best threshold was 14.7 pg/mL, the sensitivity was 90%, and the specificity was 94%. The AUC of ROC of serum cortisol at 24 h after diagnosis for predicting SAE was 0.93 (95% confidence interval was 0.86-1.00), the best threshold was 89 nmol/L, the sensitivity was 94%, and the specificity was 97%. Conclusions: Serum Tau protein, ACTH, and cortisol have high clinical diagnostic value for SAE complicated in burn patients with sepsis.

Influence of lymph node dissection in patients undergoing radical nephrectomy for non-metastatic renal cell carcinoma: a systematic review and meta-analysis.

OBJECTIVE: Whether lymph node dissection (LND) should be performed concomitantly with radical nephrectomy (RN) for non-metastatic renal carcinoma has still been controversial recently. We conducted a meta-analysis assessing oncologic outcomes of radical nephrectomy with lymph node dissection (LND) and without lymph node dissection (non-LND) in non-metastatic renal cell carcinoma (NMRCC). PATIENTS AND METHODS: A systematic review was performed until April 2018 using a comprehensive search in PubMed, EMBASE, and Cochrane Library databases to identify eligible comparative studies. A formal meta-analysis was performed for studies comparing radical nephrectomy with LND and radical nephrectomy with non-LND for cT1-T4NxM0 tumors. Furthermore, a subgroup analysis for locally advanced renal cell carcinoma (cT3-T4NxM0) was conducted. RESULTS: Thirteen studies on patients with LND and non- LND were identified and included in the analysis. LND group did not have a significantly better survival than non-LND group for cT1-T4NxM0 tumors (HR 0.93, 95% CI 0.78-1.11, p=0.45), However, in the subgroup of locally advanced renal cell carcinoma (cT3-T4NxM0), it showed a significantly better OS rate in patients who had undergone LND compared to those without LND (HR 0.73, 95% CI 0.60-0.90; p=0.003). CONCLUSIONS: LND offers better cancer control and better long-term survival in locally advanced renal cell carcinomas (cT3-T4NxM0). This conclusion should be confirmed by a prospective randomized clinical trial.

[Triptolide induces oxidative stress and apoptosis and activates PIK3/Akt signaling pathway in TM4 sertoli cells].

OBJECTIVE: To investigate the effect of triptolide (TP) on oxidative stress and apoptosis in TM4 sertoli cells and related molecular mechanism. METHODS: TM4 cells were incubated with different concentrations of triptolide for 24 h, then collected for further experiments. Cell proliferation analysis was used to measure the inhibitive effect of triptolide on proliferation of TM4 cells; DCFH-DA (6-carboxy-2',7'-dichlorofluorescein diacetate) probe was used to stain the TM4 cells, the level change of intracellular ROS was discovered through flow cytometry; the TM4 cells were stained by Annexin V-FITC/PI to detect whether triptolide induced apoptosis in the TM4 cells; Protein was extracted from the TM4 cells in control and triptolide group. Western blot was performed to determine the expression of apoptosis marker protein cleaved-PARP and PI3K/Akt signaling pathway-related proteins [p-Akt (Ser473), Akt, p-mTOR (Ser2448), mTOR, p-p70S6K (Thr389), p70S6K]. RESULTS: Cell proliferation analysis revealed that triptolide reduced the TM4 cells viability significantly compared with control group in a dosage-dependent manner [10 nmol/L: (73.77±20.95)%, 100 nmol/L: (51.60±10.43)%, 500 nmol/L: (44.34±5.78)%]; The level of intracellular ROS in the TM4 cells was significantly induced in a dosage-dependent manner (P<0.01); triptolide remarkably induced early-stage and late-stage apoptosis in the TM4 cells [control: (3.84±1.50)%, 100 nmol/L: (13.04±2.03)%, 200 nmol/L: (16.24±1.34)%, 400 nmol/L: (18.76±3.45)%]; The expression of cleaved-PARP was significantly upregulated in the TM4 cells after incubation with triptolide (P<0.01); The expression levels of p-Akt/Akt and p-p70S6K/p70s6k were significantly increased compared with control group (P<0.01). No significant change was observed among the expression levels of p-mTOR/mTOR (P>0.05). CONCLUSION: In vitro studies showed that triptolide could effectively suppress the proliferation and induce apoptosis of TM4 sertoli cells. The oxidative stress was upregulated after incubation with triptolide, which may be one of the mechanisms of cytotoxicity in TM4 cells. Treatment of triptolide led to activation of Akt and p70S6K, indicating that the PI3K/Akt signaling pathway may be involved in response to oxidative stress in TM4 cells. The activation of PI3K/Akt signaling pathway was one of the molecular mechanisms involved in triptolide-mediated oxidative stress in TM4 cells. Our study provides insight into alleviating reproductive toxicity of triptolide in clinical and developing male contraceptive.

[Clinic analysis of femtosecond laser-assisted cataract surgery].

OBJECTIVE: To evaluate the safety and effectiveness of femtosecond laser-assisted cataract surgery. METHODS: The interventional case series enrolled 314 eyes undergoing cataract surgery in Xiamen Ophthalmic Center between April and December 2013, patients were randomized to femtosecond laser-assisted cataract surgery(153 eyes) and conventional phacoemulsification cataract surgery(161 eyes). The clincic parameters of preoperation, during operation and postoperation were compared and statistically studied. Quantitative data were analyzed using the analysis of variance, independent t tests. Qualitative datawere analyzed using the crosstabs analysis chi-square test or the Fisher's exact test. RESULTS: The patient's demographics parameters(age, gender, IOP, axial length, mean keratometry, AC depth, Cataract grade) did not differ significantly between groups (P>0.05) . The CDE showing 4.78% (3.18%-8.88%) and EPT showing 14.05 s (10.07-20.85 s) in the laser group were significantly lower than the CDE showing 8.82% (6.01%-19.16%) and EPT showing 23.65 s (18.36-46.96 s) in the conventional group (z=2.30, 2.91; P<0.05) . The relative diameter and circularity in laser-assisted capusulotomies were significantly more accurate (t=2.58, 3.92; P<0.05). The corneal endothelial cell loss showing 73.50 (-69.51-111.03)/mm(2) was significantly lower in the laser group than the loss of 118.06 (53.55-299.03)/mm(2) in the conventional group 1 month postoperatively (z=2.44; P<0.05). Postoperative anterial chamber flare was significantly greater in the conventional group at 1 day of 18.81 (13.32-20.23) ph/ms in laser group, 24.51(16.38-32.18)ph/m in conventional group and at 1 month of 13.01(9.23-16.28) ph/ms in laser group, 18.05(12.37-24.97) ph/ms in conventional group than the laser group (z=2.40, 2.31; P<0.05). There were no severe surgical complications for both groups. CONCLUSIONS: The femtosecond laser-assisted cataract surgery was effective and safe. It reduced EPT and CDE during operation, therefore decreased endothelial damage and postoperative anterior chamber inflammation. It also provided more precise and reproducible capsulotomies.

Adenovirus mediated knockdown of bone morphogenetic protein 2 inhibits human lung cancer growth and invasion in vitro and in vivo.

Bone morphogenetic protein 2 (BMP-2) is a member of the TGF-beta superfamily of signaling molecules, and has been shown to function as a tumor suppressor involved in development and progression of many malignancies. BMP-2 has previously been reported to be closely correlated with lung cancer. But, the role and molecular mechanisms of BMP-2 in lung cancer have not yet been comprehensively explained. The present study aims to elucidate the role of BMP-2 in growth and invasion of human lung adenocarcinoma (LAC) in vitro and in vivo. Adenovirus vector-mediated BMP-2 small hairpin RNA (shBMP-2) was used to transfect into A549 LAC cells to determine the functional relevance of BMP-2 and tumor growth and invasion in vitro and in vivo, and further investigate the expression levels of BMP-2, vascular endothelial growth factor (VEGF), matrix metallopeptidase-9 (MMP-9), phosphatidylinositol 3-kinase p85alpha (PI3Kp85alpha) and phosphorylated AKT (p-AKT). As a result, LAC cell proliferation and invasion were significantly diminished by knockdown of BMP-2 indicated by MTT and Transwell assays, and cell apoptosis and cycle arrest were markedly induced indicated by flow cytometry. When BMP-2 expression was knocked down, the expression of PI3Kp85alpha, p-AKT, VEGF and MMP-9 was also down-regulated in LAC cells. In addition, the tumor volumes in LAC subcutaneous nude mouse model treated with shBMP-2 were significantly smaller than those in control and ad-GFP groups. Taken together, our findings indicate that knockdown of BMP-2 inhibits growth and invasion of LAC cells possibly via blockade of the PI3K/AKT signaling pathway, and BMP-2 may be a potential therapeutic target for lung cancer.

Proteins with antifungal properties and other medicinal applications from plants and mushrooms.

Living organisms produce a myriad of molecules to protect themselves from fungal pathogens. This review focuses on antifungal proteins from plants and mushrooms, many of which are components of the human diet or have medicinal value. Plant antifungal proteins can be classified into different groups comprising chitinases and chitinase-like proteins, chitin-binding proteins, cyclophilin-like proteins, defensins and defensin-like proteins, deoxyribonucleases, embryo-abundant protein-like proteins, glucanases, lectins, lipid transfer proteins, peroxidases, protease inhibitors, ribonucleases, ribosome-inactivating proteins, storage 2S albumins, and thaumatin-like proteins. Some of the aforementioned antifungal proteins also exhibit mitogenic activity towards spleen cells, nitric oxide inducing activity toward macrophages, antiproliferative activity toward tumor cells, antibacterial activity, and inhibitory activity toward HIV-1 reverse transcriptase. In contrast to the large diversity of plant antifungal proteins, only a small number of mushroom antifungal proteins have been reported. Mushroom antifungal proteins are distinct from their plant counterparts in N-terminal sequence. Nevertheless, some of the mushroom antifungal proteins have been shown to inhibit HIV-1 reverse transcriptase activity and tumor cell proliferation.

Serum amyloid A attenuates cellular insulin sensitivity by increasing JNK activity in 3T3-L1 adipocytes.

A permanent increase in acute-phase serum amyloid A (A-SAA) level is observed in obesity and insulin resistance. Recently, A-SAA has been shown to correlate with obesity and insulin resistance in human. However, what triggers A-SAA up-regulation is poorly understood, and the mechanism of elevated A-SAA to insulin resistance has not been elucidated. In this study, we used two cellular models of insulin resistance, one induced by treatment with tumor necrosis factor-alpha (TNF-alpha) and the other with the glucocorticoid dexamethasone. Gene expression analysis showed that SAA3 mRNA levels were increased in both models of insulin resistance, and ELISA showed that A-SAA levels were increased in both models too. To assess the potential impact of A-SAA on insulin resistance, we treated 3T3-L1 adipocytes with recombinant human SAA (Rh-SAA) and found that Rh-SAA attenuated cellular insulin sensitivity, up-regulated the level of phosphor-JNK, and down-regulated the level of phosphotyrosine-IRS-1 and the expression of glucose transporter 4 (GLUT4) in 3T3-L1 adipocytes. Pre-treatment of cells with C-Jun amino-terminal kinases (JNK) inhibitor brought about partial restoration of Rh-SAA-induced insulin resistance. In sum, our findings suggest that serum amyloid A might be a marker of insulin resistance, and it might play a major role in the development of obesity-related insulin resistance. Moreover, in our study it has been proved that JNK is indeed a crucial component of the pathway responsible for SAA-induced insulin resistance in 3T3-L1 adipocytes, which suggests that a selective interference with JNK activity might be a useful strategy in the treatment of Type 2 diabetes and other insulin-resistant states.

Isolation of vulgin, a new antifungal polypeptide with mitogenic activity from the pinto bean.

An antifungal polypeptide bearing an N-termnial sequence with some homology to chitinases was purified from an extract of pinto beans. The polypeptide, designated vulgin, exerted antifungal activity toward Mycosphaerella arachidicola, Coprinus cornatus, Fusarium oxysporum and Botrytis cinerea. Vulgin inhibited translation in a rabbit reticulocyte lysate system with an IC50 of 4.3 microM and HIV-1 reverse transcriptase activity with an IC50 of 58 microM. Vulgin stimulated in vitro incorporation of methyl [3H] thymidine into mouse splenocytes.

A novel peptide with ribonuclease and translation-inhibitory activities from fruiting bodies of the oyster mushroom Pleurotus ostreatus.

From the fresh fruiting bodies of the oyster mushroom a peptide with a molecular weight of 9 kDa and demonstrating a novel N-terminal sequence GPCYLVAFYESSGRR was isolated. The isolation procedure involved ion exchange chromatography on CM-Sepharose and Mono S. The peptide was adsorbed on both types of chromatographic media. The peptide demonstrated a ribonuclease activity of 650 U/mg toward yeast transfer RNA. It inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC50 of 15 nM.

A new antifungal peptide from rice beans.

A peptide, possessing a molecular mass of 5 kDa and demonstrating remarkable sequence homology to the cowpea 10 kDa protein precursor and garden pea disease resistance response protein, was isolated from rice bean seeds. The peptide was adsorbed on CM-Sepharose and Affi-gel blue gel. It inhibited mycelial growth in the fungi Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani and Mycosphaerella arachidicola. It stimulated incorporation of methyl [3H] thymidine into mouse splenocytes, inhibited the activity of human immunodeficiency virus type 1 reverse transcriptase and suppressed translation by rabbit reticulocyte lysate.

Cicerin and arietin, novel chickpea peptides with different antifungal potencies.

Two antifungal peptides with novel N-terminal sequences, designated cicerin and arietin were isolated from seeds of the chickpea (Cicer arietinum), respectively. Both peptides were adsorbed on Affi-gel blue gel and CM-Sepharose and exhibited a molecular weight of approximately 8.2 and 5.6 kDa, respectively. Arietin was more strongly adsorbed on CM-Sepharose than cicerin and manifested a higher translation-inhibiting activity in a rabbit reticulocyte lysate system and a higher antifungal potency toward Mycosphaerella arachidicola, Fusarium oxysporum and Botrytis cinerea. Both were devoid of mitogenic and anti-HIV-1 reverse transcriptase activities.

Purification of angularin, a novel antifungal peptide from adzuki beans.

An antifungal peptide was isolated from the adzuki bean with a procedure involving affinity chromatography on Affi-gel blue gel and ion exchange chromatography on CM-Sepharose. The protein designated angularin was adsorbed on both types of chromatographic media and possessed a molecular weight of 8 kDa. Angularin exhibited antifungal activity against a variety of fungal species including Mycospharella arachidiocola and Botrytis cinerea. It inhibited mycelial growth in B. cinerea with an IC50 of 14.3 microM. Fusarium oxysporum and Rhizoctonia solani were not inhibited. Angularin demonstrated inhibitory activity on translation in the rabbit reticulocyte lysate system (IC50 = 8.0 microM) but did not affect proliferation of splenocytes. The activity of HIV-1 reverse transcriptase was inhibited in the presence of angularin. Its N-terminal sequence was GEPGQKE.

Peptides from pinto bean and red bean with sequence homology to cowpea 10-kDa protein precursor exhibit antifungal, mitogenic, and HIV-1 reverse transcriptase-inhibitory activities.

Peptides with a molecular weight of 5 kDa have been isolated from seeds of the pinto bean and red bean, respectively. The peptides manifest an N-terminal sequence with remarkable resemblance to those of cowpea 10-kDa protein precursor and garden pea disease resistance response protein. The bean peptides possess potent antifungal activity toward a variety of fungal species including Botrytis cinerea, Mycosphaerella arachidicola, and Fusarium oxysporum. The proteins also demonstrate mitogenic activity toward mouse splenocytes and an inhibitory action on HIV-1 reverse transcriptase.

Intercellular transfer of a soluble viral superantigen.

Mouse mammary tumor virus (MMTV) superantigens (vSAgs) can undergo intercellular transfer in vivo and in vitro such that a vSAg can be presented to T cells by major histocompatibility complex (MHC) class II proteins on antigen-presenting cells (APCs) that do not express the superantigen. This process may allow T-cell activation to occur prior to viral infection. Consistent with these findings, vSAg produced by Chinese hamster ovary (CHO) cells was readily transferred to class II IE and IA (H-2(k) and H-2(d)) proteins on a B-cell lymphoma or mouse splenocytes. Fixed class II-expressing acceptor cells were used to demonstrate that the vSAg, but not the class II proteins, underwent intercellular transfer, indicating that vSAg binding to class II MHC could occur directly at the cell surface. Intercellular transfer also occurred efficiently to splenocytes from endogenous retrovirus-free mice, indicating that other proviral proteins were not involved. Presentation of vSAg7 produced by a class II-negative, furin protease-deficient CHO variant (FD11) was unsuccessful, indicating that proteolytic processing was a requisite event and that proteolytic activity could not be provided by an endoprotease on the acceptor APC. Furthermore, vSAg presentation was effected using cell-free supernatant from class II-negative, vSAg-positive cells, indicating that a soluble molecule, most likely produced by proteolytic processing, was sufficient to stimulate T cells. Because the membrane-proximal endoproteolytic cleavage site in the vSAg (residues 68 to 71) was not necessary for intercellular transfer, the data support the notion that the carboxy-terminal endoproteolytic cleavage product is an active vSAg moiety.

Ribonuclease, cell-free translation-inhibitory and superoxide radical scavenging activities of the iron-binding protein lactoferrin from bovine milk.

The purpose of this study was to characterize the ribonuclease (RNase) and cell-free translation-inhibitory activities of lactoferrin isolated from bovine milk. It was found that bovine lactoferrin exhibited ribonucleolytic activity toward yeast transfer RNA in a dose-dependent manner. The pH optimum for this RNase activity was in the vicinity of 7.5. Lactoferrin exerted RNase activity on poly C with an activity of 2.15 U/mg. No activity was detected toward poly A, poly G, and poly U. The milk protein inhibited cell-free translation in rabbit reticulocyte lysate with an IC50 of 9.6 microM. The protein was devoid of N-glycosidase activity characteristic of ribosome inactivating proteins which also possess RNase and cell-free translation-inhibitory activities. It inhibited superoxide radical formation.