[Microfocal prostate cancer: a clinicopathological analysis of 206 cases]

Objective: To investigate the clinical and pathological features and prognosis of patients with microfocal prostate adenocarcinoma. Methods: Clinical and pathological data of the patients diagnosed with microfocal adenocarcinoma on prostate biopsy at the West China Hospital from 2013 to 2019 were collected. Microfocal adenocarcinoma was defined as follows: Gleason score of 3+3=6, total number of the cores ≥10, number of the positive cores ≤2, and proportion of the tumor in each positive core<50%. Clinicopathological parameters, treatment plans and follow-up data were collected. Pathological information of the biopsy and radical resection specimens was used to analyze the correlation between pathological parameters in the biopsy report and adverse pathological features of radical resection specimens, including increased Gleason score, capsule invasion, positive surgical margin and perineural invasion. Results: A total of 206 cases of microfocal adenocarcinoma were diagnosed on prostate biopsies from 2013 to 2019, accounting for 6.7% of all adenocarcinoma cases. There were 139 cases of 1 positive core and 67 cases of 2 positive cores. Patients with microfocal adenocarcinoma were younger than those with non-microfocal adenocarcinoma (69 years versus 71 years, P<0.001). Compared with patients with non-microfocal adenocarcinoma, the pre-biopsy total prostate specific antigen (tPSA) and free prostate specific antigen (fPSA) levels in patients with microfocal adenocarcinoma were both lower (11.2 μg/L² versus 23.7 μg/L²; 1.4 μg/L² versus 3.0 μg/L², P<0.001), the fPSA/tPSA level was higher (12.9% versus 10.7%, P<0.05), the prostate volume was larger (38.9 mL versus 34.3 mL, P<0.05), and the PSA density was lower (0.3 μg/L² versus 0.8 μg/L², P<0.001). 130 patients underwent radical prostatectomy, 30 patients chose active monitoring, 31 patients chose endocrine or radiation therapy, and 15 patients were lost to follow-up. Three patients in the active surveillance group underwent radical prostatectomy for disease progression after 21-39 months observation. Biochemical relapses occurred in two patients in the radical prostatectomy group. The remaining patients have no disease progression or recurrence at present. Compared with radical prostatectomy specimens, Gleason score in the biopsy material was increased in 64/115 patients (55.7%). Among resection excision specimens, 14 cases (12.2%) had extraprostatic extension (EPE), 35 cases (30.4%) had perineural invasion, and 16 cases (13.9%) had a positive margin. Univariate and multivariate analyses showed that low fPSA/tPSA ratio and 2 positive cores were independent risk factors for Gleason score increase in the radical prostatectomy specimens. A low fPSA/tPSA ratio was an independent risk factor for perineural invasion. Low fPSA/tPSA ratio and low prostate volume were associated with a positive margin in radical prostatectomy specimens. Conclusions: In this study, patients diagnosed with microfocal adenocarcinoma on prostate biopsy account for a high proportion of the patients with increased Gleason score in the radical prostatectomy specimens, and there is a certain proportion of adverse pathological features in the radical specimens. Therefore, for the patients with only a small amount of low-grade adenocarcinoma found in biopsy, PSA levels and PSA density should be taken into consideration in treatment selection.

Abstract LB213: Potent antitumor activity of a FGFR4 CAR-T in rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is an aggressive soft tissue sarcoma originating from skeletal muscle in children and adolescent young adults. Despite multi-modal aggressive therapies, relapsed, refractory or metastatic rhabdomyosarcoma remains a lethal disease with no significant improvement in outcome over decades of clinical trials. Therefore novel therapies are needed. FGFR4 is a developmentally regulated cell surface receptor tyrosine kinase that is overexpressed in RMS when compared with normal tissues, and mutationally activated in about 7.5% of RMS. Recently we showed that PAX3-FOXO1 establishes a super-enhancer in the FGFR4 genomic locus driving its high expression in fusion positive RMS. CAR T-cell therapy is effective in treating refractory and relapsed B-cell leukemia and lymphoma, with three CARs targeting CD19 approved by the FDA. Multiple CART trials are currently underway for solid tumors. Since FGFR4 is a cell surface protein, we hypothesized that FGFR4 will provide a rational target for immunotherapy in RMS. We confirmed by immunohistochemistry staining, western analysis, and Meso Scale Discovery that FGFR4 protein is highly differentially expressed in RMS samples. We developed a murine anti-FGFR4 antibody, 3A11, by immunizing mouse with FGFR4-IG fusion protein. 3A11 showed high affinity and specificity of binding to FGFR4. We then developed a second-generation CAR using the VL and VH domain of 3A11 antibody and found that the scFvFc retained its specificity and high affinity at nanomolar range. Human T cells transduced with 3A11 CAR construct were found to be highly potent at inducing IFN-γ, TNF-α, IL-2 and cytotoxicity when the FGFR4-CART was co-cultured with RMS cells, but not with RMS cells with FGFR4 knocked out or FGFR4 negative cells. 3A11 CART incubated with human primary cells obtained from liver, kidney, heart, and pancreas, did not elicit a cytokine response, indicating a low potential for “on-target off-tumor” toxicity. In vivo testing also found that 3A11 CART eliminated RMS cells in both murine xenograft metastatic and localized subcutaneous models. Therefore we have developed a CART targeting FGFR4 that shows high potency for treating RMS. A phase 1 FGFR4-CART clinical trial is planned for children and adolescent young adults with relapsed/refractory rhabdomyosarcoma.

Citation Format: Adam Tai Chi Cheuk, Meijie Tian, Nityashree Shivaprasad, Steven Highfill, David Milewski, G Tom Brown, Peter Azorsa, Dina Schneider, Berkley Gryder, Jun S Wei, Young Kwok Song, Hsien-Chao Chou, Jerry Wu, Joon-Yong Chung, Brian Belyea, Corinne Linardic, Stephen M Hewitt, Boro Dropulic, Rimas Orentas, Javed Khan. Potent antitumor activity of a FGFR4 CAR-T in rhabdomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB213.

Photoemission Spectroscopic Evidence for the Dirac Nodal Line in the Monoclinic Semimetal SrAs_{3}

Topological nodal-line semimetals with exotic quantum properties are characterized by symmetry-protected line-contact bulk band crossings in the momentum space. However, in most of identified topological nodal-line compounds, these topological nontrivial nodal lines are enclosed by complicated topological trivial states at the Fermi energy (E_{F}), which would perplex their identification and hinder further applications. Utilizing angle-resolved photoemission spectroscopy and first-principles calculations, we provide compelling evidence for the existence of Dirac nodal-line fermions in the monoclinic semimetal SrAs_{3}, which possesses a simple nodal loop in the vicinity of E_{F} without the distraction from complicated trivial Fermi surfaces. Our calculations revealed that two bands with opposite parities were inverted around Y near E_{F}, resulting in the single nodal loop at the Γ-Y-S plane with a negligible spin-orbit coupling effect. The band crossings were tracked experimentally and the complete nodal loop was identified quantitatively, which provide a critical experimental support for the existence of nodal-line fermions in the CaP_{3} family of materials. Hosting simple topological nontrivial bulk electronic states around E_{F} and without complication from the trivial states, SrAs_{3} is expected to be a potential platform for topological quantum state investigation and applications.

The robustness of T2 value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI

PURPOSE

To evaluate the robustness of MR transverse relaxation times of trabecular bone from spin-echo and gradient-echo acquisitions at multiple spatial resolutions of 7 T.

METHODS

The effects of MRI resolutions to T₂ and T2* of trabecular bone were numerically evaluated by Monte Carlo simulations. T₂ , T2*, and trabecular structural indices from multislice multi-echo and UTE acquisitions were measured in defatted human distal femoral condyles on a 7 T scanner. Reference structural indices were extracted from high-resolution microcomputed tomography images. For bovine knee trabecular samples with intact bone marrow, T₂ and T2* were measured by degrading spatial resolutions on a 7 T system.

RESULTS

In the defatted trabecular experiment, both T₂ and T2* values showed strong ( |r| > 0.80) correlations with trabecular spacing and number, at a high spatial resolution of 125 µm³ . The correlations for MR image-segmentation-derived structural indices were significantly degraded ( |r| < 0.50) at spatial resolutions of 250 and 500 µm³ . The correlations for T2* rapidly dropped ( |r| < 0.50) at a spatial resolution of 500 µm³ , whereas those for T₂ remained consistently high ( |r| > 0.85). In the bovine trabecular experiments with intact marrow, low-resolution (approximately 1 mm³ , 2 minutes) T₂ values did not shorten ( |r| > 0.95 with respect to approximately 0.4 mm³ , 11 minutes) and maintained consistent correlations ( |r| > 0.70) with respect to trabecular spacing (turbo spin echo, 22.5 minutes).

CONCLUSION

T₂ measurements of trabeculae at 7 T are robust with degrading spatial resolution and may be preferable in assessing trabecular spacing index with reduced scan time, when high-resolution 3D micro-MRI is difficult to obtain.

Ultrafast 3D spin-echo acquisition improves Gadolinium-enhanced MRI signal contrast enhancement

Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T₂* effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (×32) and compressed sensing (CS) sampling (×8) allowed highly-accelerated 3D Multiple-Modulation-Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (×7) over that of corresponding FLASH acquisitions (×2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution.

Magnetic field anisotropy based MR tractography

Non-invasive measurements of structural orientation provide unique information regarding the connectivity and functionality of fiber materials. In the present study, we use a capillary model to demonstrate that the direction of fiber structure can be obtained from susceptibility-induced magnetic field anisotropy. The interference pattern between internal and external magnetic field gradients carries the signature of the underlying anisotropic structure and can be measured by MRI-based water diffusion measurements. Through both numerical simulation and experiments, we found that this technique can determine the capillary orientation within 3°. Therefore, susceptibility-induced magnetic field anisotropy may be useful for an alternative tractography method when diffusion anisotropy is small at higher magnetic field strength without the need to rotate the subject inside the scanner.

OK-432 sclerotherapy of plunging ranula in 21 patients: it can be a substitute for surgery

BACKGROUND AND PURPOSE

Although first-choice therapy for the ranula is surgery, this choice presents technical difficulties and frequent recurrences because of insufficient surgery. We evaluated the efficacy of OK-432 sclerosis of the plunging ranula as a substitute for surgery.

METHODS

Twenty-one patients with plunging ranula were treated with intralesional injection of OK-432. The liquid content of the ranula was aspirated as much as possible, after which OK-432 solution was injected in the same volumes as that drawn out. Patients were followed on sonography or CT.

RESULTS

Seven (33.3%) patients with plunging ranulas showed total shrinkage and resolution, and 4 (19%) patients showed near-total shrinkage (more than 90% of the volume). Four (19%) patients revealed marked shrinkage (more than 70% of the volume), and 3 (14.3%) patients showed partial shrinkage (less than 70% of the volume). Three (14.3%) patients showed recurrence after total shrinkage 1 month after injection. The overall recurrence rate after each injection was 47% (16 of 34 injections in 21 patients), but the recurrence rate after the last sclerotherapy was only 14%. There were no serious side effects except for fever lasting 2-3 days (12 patients) and swelling (10 patients) for 3-5 days. Mild odynophagia for 1-2 days was also noted in 7 patients, and there was 1 severe case of odynophagia.

CONCLUSION

OK-432 sclerotherapy of plunging ranula is a safe and potentially curative procedure that may be used as a primary treatment for plunging ranula before considering surgery.

Hydroporation as the mechanism of hydrodynamic delivery

We have reported that a rapid tail vein injection of a large volume of plasmid DNA solution into a mouse results in high level of transgene expression in the liver. Gene transfer efficiency of this hydrodynamics-based procedure is determined by the combined effect of a large volume and high injection speed. Here, we show that the hydrodynamic injection induces a transient irregularity of heart function, a sharp increase in venous pressure, an enlargement of liver fenestrae, and enhancement of membrane permeability of the hepatocytes. At the cellular level, our results suggest that hepatic delivery by the hydrodynamic injection is accomplished by the generation of membrane pores in the hepatocytes.

Sodium nitroprusside enhances TRAIL-induced apoptosis via a mitochondria-dependent pathway in human colorectal carcinoma CX-1 cells

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL, Apo-2L) is a recently characterized member of the family of programmed cell death-inducing ligands that includes TNF-alpha and CD95L (FasL). It is well known that TRAIL binds to the death signaling receptors, DR4 and DR5, and initiates the TRAIL death pathway. Activation of this pathway, mediated through a caspase cascade, causes apoptosis. In this study, we hypothesized that oxidative stress facilitates TRAIL-induced apoptosis by promoting caspase activity through cytochrome c release from mitochondria. Human colorectal carcinoma CX-1 cells were treated with various concentrations of TRAIL (12.5-200 ng/ml) and/or sodium nitroprusside (SNP; 0.03-1 mM) for 12 h. SNP, a nitric oxide donor, which had little toxic effect by itself, enhanced TRAIL-induced cytotoxicity. For example, TRAIL-induced apoptosis (200 ng/ml) was increased by a factor of 2.5-fold in the presence of 1 mM SNP. The combined treatment also caused an increase in cytochrome c release, caspase-3 activity, and PARP cleavage. Overexpression of Bcl-2 completely blocked the SNP-promoting effects, but only moderately inhibited TRAIL-induced apoptosis. Similar results were observed in the presence of hydrogen peroxide or peroxynitrite. Taken together, the present studies suggest that SNP enhances TRAIL-induced cytotoxicity by facilitating the mitochondria-mediated caspase signal transduction pathway.

Lower gastrointestinal bleeding due to cytomegalovirus ileal ulcers in an immunocompetent man

Cytomegalovirus (CMV) infections are commonly reported in severely immunocompromised hosts and ulcers of the alimentary tract are frequently observed in systemic CMV infections. However, invasive and ulcerative disease of the gastrointestinal (GI) tract caused by CMV has also been reported in healthy adults. Many reports show that a CMV infection can produce localized ulcerations in the esophagus, stomach, small intestine, and colon in nonimmunocompromised individuals. The most common site of involvement by CMV infection in the GI tract is the colon followed by the upper GI tract and the least common site is the small intestine. Although GI bleeding is one of the major presenting symptoms of patients with CMV infections of the GI tract, lower GI bleeding due to CMV ileal ulcers in immunocompetent patients, to our knowledge, has not been reported in the English literature. Recently, we experienced a case of lower GI bleeding due to CMV ileal ulcers in a 57-year-old man who had no evidence of immunocompromise. This case suggests that small intestinal ulcers due to CMV infection should be included in the differential diagnosis of lower GI bleeding even in immunocompetent hosts.

Long-term expression of human alpha1-antitrypsin gene in mouse liver achieved by intravenous administration of plasmid DNA using a hydrodynamics-based procedure

The liver is an important target organ for gene transfer due to its large capacity for synthesizing serum proteins and its involvement in numerous genetic and acquired diseases. Previously, we and others have shown that an efficient gene transfer to liver cells in vivo can be achieved by an intravenous injection of plasmid DNA using a hydrodynamics-based procedure. In this study, we systematically characterized the expression of transgene encoding a secretory protein in mouse. Using human alpha1-antitrypsin (hAAT) gene as a reporter, we demonstrate that the serum level of hAAT can reach as high as 0.5 mg/ml by a simple tail vein injection of 10-50 microg plasmid DNA into a mouse. The serum hAAT reaches the peak level 1 day after DNA injection and then declines during the following 2 to 4 weeks to 2-5 microg/ml, a level which persists for at least 6 months. Southern analysis of extracted DNA and RT-PCR analysis of RNA from the liver reveal that hAAT gene is active and present as episomal form after 6 months. These results suggest that the hydrodynamics-based transfection procedure provides a valuable tool for screening genes for therapeutic purposes in whole animals.

Structural basis of DOTMA for its high intravenous transfection activity in mouse

Eleven structural analogues of two known cationic lipids, N-[1-(2, 3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA) and N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP) were synthesized and utilized to evaluate the structural characteristics of DOTMA for its high intravenous transfection activity. Using a CMV-driven expression system and luciferase gene as a reporter, the transfection activity of these analogues was evaluated in mice using tail vein injection. Results concerning the structure-activity relationship with regard to the influence of the backbone, relative position between head group and the hydrophobic chains on the backbone, linkage bonds, as well as the composition of the aliphatic chains revealed that cationic lipids which give a higher in vivo transfection activity share the following structural characteristics: (1) cationic head group and its neighboring aliphatic chain being in a 1,2-relationship on the backbone; (2) ether bond for bridging the aliphatic chains to the backbone; and (3) paired oleyl chains as the hydrophobic anchor. Cationic lipids without these structural features had lower in vivo transfection activity. These structural characteristics, however, did not significantly influence their in vitro transfection activity. The contribution that cationic lipids make to the overall in vivo transfection activity is likely to be determined by the structure of DNA/lipid complexes and by the outcome of the interaction between the DNA/lipid complexes and blood components upon intravenous administration.

Comparison of incidence of gastroesophageal reflux and regurgitation associated with timing of removal of the laryngeal mask airway: on appearance of signs of rejection versus after recovery of consciousness

STUDY OBJECTIVES

To compare the incidence of gastroesophageal reflux and regurgitation associated with laryngeal mask airway (LMA) removal when signs of rejecting the LMA, such as swallowing, struggling, and restlessness, were observed and when the patient could open his or her mouth on command.

DESIGN

Randomized clinical trial.

SETTING

Operating room and recovery room of a tertiary care referral hospital.

PATIENTS

63 ASA physical status I and II adult patients scheduled for elective orthopedic surgery.

INTERVENTIONS

Using a standardized general anesthetic technique, patients were allocated randomly to Group A (n = 34; LMA removed when signs of rejection, such as swallowing, struggling, and restlessness, were observed) or Group B (n = 29; LMA removed when the patient could open his or her mouth on command).

MEASUREMENTS AND MAIN RESULTS

To detect gastroesophageal reflux throughout anesthesia, a pH monitoring probe was positioned in the lower esophagus on the day before surgery. To assess regurgitation during emergence, a gelatin capsule of methylene blue (50 mg) was swallowed prior to induction. At the end of anesthesia, episodes of reflux and regurgitation of gastric contents were analyzed/determined by pH below 4 and bluish staining of the pharynx and/or LMA, respectively. Physical events such as bucking, straining, and coughing during the arousal phase were recorded in both groups by an independent observer. The incidence of reflux (pH < 4) from the time of the appearance of rejection signs to LMA removal and the total incidence of reflux in Group B were significantly higher than in Group A (p < 0.05). Staining of the LMA and the pharynx by methylene blue was not observed in patients from either experimental group. The number of physical events in Group B during the arousal phase was significantly increased compared to Group A (p < 0.05). Considering all patients in Group A and Group B, physical events were associated with the occurrence of reflux (p < 0.05). Desaturation (SpO2 < 95%) and clinical evidence of aspiration of gastric contents did not occur in either group.

CONCLUSION

Maintenance of the LMA until the patient can open his or her mouth on command increases the incidence of gastroesophageal reflux.

Synthesis and characterization of aromatic ring-based cationic lipids for gene delivery in vitro and in vivo

A new series of cationic lipids has been synthesized for gene delivery using 3,5-dihydroxybenzyl alcohol as the backbone and starting material. Using CMV driven expression system and luciferase gene as a reporter, we demonstrated that the transfection activity of these new lipids when formulated with Tween 80 as co-lipid is comparable to that of DOTAP, one of the most commonly used cationic lipids for transfection. Among the four different cell lines tested including murine melanoma BL-6 cells, human embryonic kidney 293 cells, HepG2 and HeLa cells, the highest transgene expression was seen in 293 cells. Results from in vivo experiments using mice as an animal model show that these cationic lipids preferentially transfect the cells in the lung upon tail vein administration. The cationic lipid, N,N,N-trimethyl-N-[3,5-bis(tetradecyloxy)benzyl] ammonium bromide 4c(di-C14:0) with two 14-hydrocarbon chains exhibits the best transfection activity. These results suggest that these new aromatic ring-based cationic lipids are useful transfection reagents for both in vitro and in vivo gene transfer studies.

Enhanced gene expression in mouse lung by prolonging the retention time of intravenously injected plasmid DNA

The effect of retention time of plasmid DNA in mouse lung on the level of transgene expression after intravenous administration was examined. Using CMV driven expression system with luciferase gene as a reporter and preinjection of free cationic liposomes into the animal as means of manipulating the retention time of plasmid DNA, we demonstrated that naked plasmid DNA is effective in transfecting cells in the lung by intravenous administration. An increase in DNA retention time in the lung results in a higher level of gene expression. Liposomes composed of cationic lipids with alkyl chains exhibited better activity than cholesterol-based cationic liposomes to retain the plasmid DNA in the lung. The level and patterns of gene expression obtained appeared similar to those seen in animals transfected by DNA-liposome complexes. These results suggest that prolonging the exposure time of DNA to the target cells in vivo may be an important strategy in achieving a high level of gene expression. Our data also introduce a possibility that the function of cationic liposomes in lipoplex-mediated transfection in vivo is to extend the interaction time of DNA with the cells.

Free liposomes enhance the transfection activity of DNA/lipid complexes in vivo by intravenous administration

Factors that regulate the transfection efficiency of cationic lipid-based carriers are still largely unknown. We have shown in a previous report [F. Liu, H.W. Qi, L. Huang, D. Liu, Factors controlling the efficiency of cationic lipid-mediated transfection in vivo via intravenous administration, Gene Ther., 4 (1997) 517-523. ] that the transfection efficiency, to the lung, of a lipid formulation composed of N-[1-(2,3-dioleoyloxy)propyl-N,N, N-trimethylammonium chloride (DOTMA) and Tween 80 is directly proportional to the ratio of DOTMA to DNA. In this study, we investigated the mechanism underlying the high cationic lipid to DNA ratio dependent transfection activity. Specifically, we have examined the role of free cationic liposomes in affecting the transfection efficiency of the DNA/lipid complexes in vivo by intravenous administration. The data show that greater transfection activity of DNA/lipid complexes in the lung at a higher cationic lipid to DNA ratio is due to the function of free liposomes present in the DNA/lipid mixture. Free liposomes enhance the transfection activity of DNA/lipid complexes by increasing the retention time of DNA and decreasing transgene degradation in different organs. In addition to DOTMA liposomes, liposomes composed of 1,2-dioleoyl-3-trimethylammonium propane chloride (DOTAP) and 3beta[N-(N', N'-dimethylaminoethane) carbamoyl] cholesterol (DC-Chol) also enhance the level of gene expression in animals transfected by DNA/DOTMA complexes. These results suggest that inclusion of free liposomes into the DNA/lipid complexes may be important in achieving an optimal transfection activity in vivo.

Characterization of cationic liposome-mediated gene transfer in vivo by intravenous administration

Physicochemical properties of the cationic liposomes, including structure of the cationic lipid-to-DNA ratio, liposome particle size, and inclusion of the helper lipids, were studied for their effect on the level, site, and duration time of gene expression in vivo by intravenous administration. Using a cytomegalovirus (CMV)-driven gene expression system containing either the luciferase or green fluorescence protein gene as a reporter and two cationic lipids [N-(2,3-dioleoyloxy)propyl-N,N,N-trimethylammonium chloride (DOTMA) and 1,2-dioleoyloxy-3-trimethylammonium propane (DOTAP)], we demonstrated in vivo by a single intravenous injection of DNA/liposome complexes into mice, that cationic liposomes are capable of transfecting cells in organs such as the lung, heart, liver, spleen, and kidney. Transfection efficiency is determined mainly by the structure of the cationic lipid and the ratio of cationic lipid to DNA. Although the presence of cholesterol in DOTAP liposomes did not affect transfection activity, inclusion of dioleoylphosphatidylethanolamine (DOPE) into either DOTAP or DOTMA liposomes significantly decreases liposome transfection activity in vivo. Results form time course show that gene expression in different organs is transient, with a peak level between 4 and 24 hr, dropping to less than 1% of the peak level by day 4. Experiments with repeated injections showed that the peak level of gene expression could be regained by subsequent injection.

Antibody mediated lung targeting of long-circulating emulsions

Monoclonal antibody 34A, which specifically binds to a surface glycoprotein (thrombomodulin) of the pulmonary endothelial cell surface in mice, has been conjugated to the surface of long-circulating emulsions composed of Castor oil, phosphatidylcholine and polyethylene glycol coupled to distearoylphosphatidyl-ethanolamine. These antibody-containing emulsions were found capable of binding to the lung when injected into mice through the tail vein. The level of lung accumulation of these emulsions depends on the amount of antibodies conjugated to the surface of the emulsions. With an input antibody to lipid ratio of 2:1 (w/w), 30% injected emulsions were found in the lung 30 minutes after administration. Such high level accumulation can be blocked by co-administration of free 34A antibody, indicating that the binding is specific and 34A antibody mediated. Kinetic studies showed that emulsion targeting to the lung was very rapid. Five minutes after tail vein injection, the total amount of emulsion found in the lung was the highest among the time points examined, indicating the completion of lung binding. However, about 50% of the initially bound emulsions remained bound for more than 4 hours. These results indicate that the targeted drug delivery using oil-in-water emulsions could be very useful to enhance the therapeutic efficacy of lipophilic drugs.

Liposome clearance from blood: different animal species have different mechanisms

The kinetics of blood clearance and the mechanisms of liposome uptake by the reticuloendothelial system (RES) were compared in two animal species (mice and rats). By employing an in situ liver perfusion technique with selected liposome compositions (PC/Chol, PC/Cho/PS, PC/Chol/GM1 and PC/Chol/PEG5000-PE), we demonstrated that liposomes with same lipid composition exhibited different blood circulation half-lives in different animal species. Although liver is the major organ responsible for the clearance of liposomes from blood in both animal species, the specific mechanisms differ. In mice, liposome uptake by the liver did not involve specific serum opsonins. In contrast, liposome uptake by the rat liver was strongly dependent on serum opsonins. Further, the activity of serum opsonins for a given liposome composition differed among animal species. Human serum exhibited higher opsonin activities for PC/Chol and PC/Chol/GM1 liposomes than bovine sera, while rat serum displayed a high opsonizing activity for GM1 liposomes and none for liposomes composed of PC and Chol. The opsonin activity of human serum could be removed or decreased by treatment with EGTA/Mg2+, EDTA or cobra venom factor, suggesting that the activity is likely due to complement components. It is likely that C3 of the human complement system plays an important role in mediating the uptake of liposomes by the liver.

Antibody dependent, complement mediated liver uptake of liposomes containing GM1

PURPOSE

We have previously reported that GM1 exhibits an opposite effect on regulating liposome circulation time in mice and rats (Liu et al. Pharm. Res. Vol. 12:508-512 (1995)). Inclusion of GM1 into liposomes significantly prolongs liposome circulation time in mice, while it dramatically decrease the blood half life and increases liver uptake of liposomes in rats. The purpose of this study was to elucidate the mechanism that underlies this phenomenon.

METHODS

Single-pass liver perfusion in vitro and complement mediated liposome lysis assay was used.

RESULTS

Serum appeared to play an important role in determining the liver uptake of GM1 liposomes. Specifically, rat serum enhanced the uptake of GM1-containing liposomes by the perfused liver. Such activity was also found in human and bovine serum, but not in mouse serum. Taking human serum as an example, we demonstrated that such serum activity can be blocked by EDTA and EGTA/Mg2+. Antibodies against human IgM and the third component of complement system (C3) also inhibited serum activity.

CONCLUSIONS

The presence of naturally occurring anti-GM1 antibodies in rats, through the activation of the classic pathway of complement system, is likely the cause of rapid blood clearance of GM1-liposomes. The third component of complement is likely to serve as the opsonin that is directly involved in mediating liposome clearance.

Recognition and clearance of liposomes containing phosphatidylserine are mediated by serum opsonin

Liver uptake of liposomes containing phosphatidylserine was studied in a single pass liver perfusion system and found to be serum dependent. The effectiveness of serum in mediating liposome uptake by the liver depends on liposomes size. Large liposomes appeared to be opsonized more efficiently and, therefore, taken up more by the liver than the smaller ones. The effects of liposomes size on liver uptake did not occur in the absence of serum. Treatment of serum at 56 degrees C for 30 min abolished the serum activity, suggesting the involvement of complement components. Inhibition of the hemolytic activity of complement through the alternative pathway by PS-containing liposomes suggests that components in this pathway are responsible for liposome opsonization. Liposomes containing phosphatidic acid, phosphatidylglycerol, and dicetyl phosphate compete in different degrees for serum components which mediate the liver uptake of PS-containing liposomes. These results suggest that the opsonization of liposomes by serum opsonins are the determining factors for the recognition and clearance of liposomes by the RES. Complement components are most likely involved in this process. The results presented here are relevant to the use of liposomes as drug delivery vehicle in vivo and to the PS-mediated clearance of red blood cells from the blood circulation.

Monosialoganglioside GM1 shortens the blood circulation time of liposomes in rats

Inclusion of monosialoganglioside GM1 into liposomes significantly enhances the circulation time of liposomes in mice. Conversely, intravenously injected GM1-containing liposomes were rapidly removed from the blood circulation and accumulated in the liver and spleen in rats. In rats, increasing the GM1 content in liposomes resulted in more rapid clearance from the blood. Increasing the membrane rigidity of liposomes further increased the liver uptake of GM1-containing liposomes. The activity of GM1 in enhancing the liposome uptake by rat liver appears to be mediated by complement components.

[Experimental study of pathogenic effects of dusts of vanad-titan-magnetite on rats lungs]

The present study is concerned with the pulmonary pathological changes in the rats following intra-tracheal administration of sintering dust and vanadium slag separately. The results indicated that both the volume of lungs and the quantity of pulmonary collagen protein in the treated groups were higher than those in the control groups. The histopathological observations revealed foci of dust cells and fibers in the pulmonary alveoli, bronchi and around the blood vessels, a small amount of reticular fibers and collagenous fibers were also seen. At the same time bronchitis, pulmonary emphysema and atelectasis can also be seen. The pathological changes in the vanadium slag groups were more distinct than those in the sintering dust groups. The paper briefly discussed these pathological changes from the standpoint of the chemical composition of the dusts, dose-response relation, etc.

Oxygen equilibria of ectotherm blood containing multiple hemoglobins

Complete isocapnic O2 equilibrium curves (O2EC's) and related blood-gas properties are reported for whole blood of the bullfrog (Rana catesbeiana) and the aquatic turtle (Pseudemys scripta) at temperatures ranging from 5 to 35 degrees C. P50's for bullfrog and turtle blood at physiological pH and 25 degrees C were 36.6 Torr (pH 7.83) and 19.3 Torr (pH 7.55), respectively. Elevation of blood temperature significantly reduced hemoglobin oxygen affinity in both species (delta H = -8.1 and -7.8 kcal/mol O2 for Rana and Pseudemys, respectively). Bullfrog and turtle oxygen equilibrium data revealed non-standard curve shapes when compared with the Severinghaus curve for human blood (1979); ectotherm O2EC's rose more steeply below P50 (less sigmoid) and were distinctly flattened (linear) above 50% saturation. The CO2-Bohr effect for bullfrog and turtle blood varied significantly as a function of saturation. In addition, both species exhibited non-linear Hill relationships (logS/1-s vs. log PO2). These results indicate that the oxygen binding properties of the multiple hemoglobin bloods of Rana and Pseudemys (demonstrated by isoelectric focusing) are more complex than those exhibited by normal human blood. As a consequence, these ectotherm blood oxygen data are not well characterized by the limited number of simple descriptive parameters (P50, Hill's n and delta log P50/delta pH) commonly used to delineate predominantly single hemoglobin systems.

Effects of SCN- and NO3- on organic anion transport in rabbit kidney cortical slices

1. The effects of replacement of Cl- by either SCN- or NO3- on the accumulation of p-aminohippurate, the efflux of pre-accumulated p-amino-hippurate and kinetics of p-aminohippurate uptake were investigated in the rabbit kidney cortical slice. 2. The total replacement of Cl- in the incubation medium with SCN- decreased the 60-min slice-to-medium concentration ratio (S/M) of p-amino-hippurate by 75% and that with NO3- by 40%. 3. The decrease in p-aminohippurate accumulation by the inorganic ions was found to be specific for organic anion transport since the uptake of the organic cation, tetraethylammonium, was not influenced by inorganic ions. 4. The influence of NO3- on p-aminohippurate uptake was fully reversible: however, the effect of SCN- could only be partially reversed. 5. Both SCN- and NO3- significantly increased the Km value but had no significant effect on the V value of the p-aminohippurate uptake process. 6. These findings suggest that both SCN- and NO3- are competitive inhibitors of p-aminohippurate transport and, also, that SCN- appears to bind to a membrane component involved in the transport of p-aminohippurate.

Effect of SITS on organic anion transport in the rabbit kidney cortical slice

The effect of SITS (4-acetamido-4'-isothiocyano-2,2'-disulfonic stilbene) on the transport of organic ions in the rabbit kidney cortical slice was studied. SITS at a concentration of 10(-4) to 10(-3) M significantly decreased the slice-to-medium (S/M) concentration ratio of the organic anions p-aminohippurate (PAH), and 2,4,5-trichlorophenoxyacetate, but had no significant effect on that of the organic cation tetraethylammonium. The S/M ratio of PAH decreased to 0.52 +/- 0.03 (SE) in the presence of 10(-3) M SITS. The inhibition of PAH uptake caused by SITS was reversed in the presence of 0.5% bovine serum albumin in the medium. SITS at a concentration of 10(-4) M had no significant effect on the efflux of PAH. However, there was a small increase in PAH efflux at a concentration of 10(-3) M SITS. A Lineweaver-Burk analysis of the data indicates that SITS competitively inhibits PAH uptake and that SITS has a Ki value of 2.3 X 10(-4) M. SITS had no effect on the tissue water content, [14C]inulin space, or intracellular Na and K concentrations. It is suggested that the primary effect of SITS is to inhibit the entry of organic anions from the medium into the cell across the basolateral membrane.

Behavior of Mycobacterium leprae in human macrophages in vitro

Attempts have been made to cultivate Mycobacterium leprae in human macrophages in vitro. In 27 out of 55 experiments a two- to ninefold increase (mean 2.31 +/- 1.46) in acid-fast organisms were observed over a period of 1.5 to 3 months of cultivation. No such increase was observed with heat-killed bacilli (mean fold increase 0.88 +/- 0.19). Macrophages were necessary for obtaining increases. No multiplication was observed on artificial media. A close correlation between increases of acid-fast organisms and changes in viability as determined by the morphology of the bacilli (morphologic index) was found. The increases in acid-fast organisms could be inhibited by anti-leprosy drugs. It is concluded that multiplication of M. leprae may take place inside human macrophages in vitro. Multiplication appears not to be dependent on whether the macrophages are derived from lepromatous or tuberculoid patients or healthy individuals. Moreover, multiplication took place both at 33 and 37 C. The applicability of this method is at present limited by the restricted survival of human macrophages in vitro.

Immune responsiveness to Mycobacterium leprae and other mycobacterial antigens throughout the clinical and histopathological spectrum of leprosy

Immunological responsiveness was studied throughout the clinical and histopathological spectrum of leprosy (Ridley–Jopling scale) by the methods of lymphocyte transformation, leucocyte migration inhibition and delayed skin hypersensitivity,

The response to Mycobacterium leprae showed by all methods a continuous decrease from strong responses in the polar tuberculoid (TT) group to virtually negative responses in the polar lepromatous (LL) group. There was a good agreement between the in vitro methods and the lepromin skin test, giving support to the latter as useful tool in the evaluation of immune responsiveness to M. leprae in leprosy patients.

The immune response to BCG and PPD on the other hand, decreased only slightly towards the lepromatous pole of the spectrum, confirming the high degree of specificity of the immune defect in lepromatous leprosy. Patients grouped histologically as subpolar tuberculoid (TT/BT) reacted particularly strongly to BCG and PPD.

As it is likely that the methods used mainly measured T-lymphocyte function, the clinicopathological manifestations of leprosy appear to reflect the strength of the cellular immune response against M. leprae. Thus the findings give strong support to the concept of a host-determined, immunological diseases pectrum as expressed in the Ridley–Jopling classification.