Management of malignant pleural effusion by suicide gene therapy in advanced stage lung cancer: a case series and literature review.

Gene therapy can be defined as the transfer of genetic material into a cell for therapeutic purposes. Cytosine deaminase (CD) transferred into tumor cells by an adenoviral vector (Ad.CD), can convert the antifungal drug fluorocytosine (5-FC) to the antimetabolite 5-fluorouracil (5-FU), which kills not only the transfected tumor cells but also their neighbors by the so-called 'bystander effect'. After testing a protocol for Ad.CD transfer and lung tumor burden control in a Lewis mouse model, we used this technique in the management of lung cancer patients with malignant pleural effusion (MPE): two cases are presented investigating the possible enhancement of anticancer effect in both non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC) by local activation of the pro-drug 5-FC. Results were discussed in parallel to a literature review on the topic. 5-FC and Ad.CD were administered intratumorally to Lewis mouse lung carcinoma and the effect was monitored by tumor size and electromicroscopy. Two patients with advanced stage lung cancer (1SCLC, 1NSCLC), which developed MPE during first-line treatment were administered 10(12) plaque-forming unit (pfu) Ad.CD by intrapleural instillation, in two doses (day 1 and day 7). Instillation was performed when the pleural fluid was ≤200 ml. In addition, they received 5-FC 500 mg four times daily for 14 days. Lung tumor regression and successful transfer of adenoviral particles were observed in treated animals. Patients presented complete regression of pleural effusion as monitored by computerized tomography scan. Neutrapenia and anemia were the most severe adverse effect presented (grade III/grade IV 100%). The increased toxicity followed by the intrapleural gene therapy indicates the augmentation of anticancer effect of transformed pro-drug 5-FC to active 5-FU. The obtained data indicate that intrapleural gene therapy may be a useful tool, adjunct to chemotherapy, in the management of MPE related to lung cancer.

EphrinA1 inhibits malignant mesothelioma tumor growth via let-7 microRNA-mediated repression of the RAS oncogene.

EphrinA1 binding with receptor EphA2 suppresses malignant mesothelioma (MM) growth. The mechanisms whereby EphrinA1 attenuates the MM cell (MMC) growth are not clear. In this study, we report that the activation of MMCs with EphrinA1 leads to an induction of let-7 microRNA (miRNA) expression, repression of RAS proto-oncogene and the attenuation of MM tumor growth. The expression of miRNAs was determined by reverse transcription-quantitative polymerase chain reaction and in situ hybridization. RAS expression was determined by q-PCR, western blotting and immunofluorescence. MMC proliferation and tumor growth were determined by WST-1 and Matrigel assay, respectively. EphrinA1 activation induced several fold increases in let-7a1, let-7a3, let-7f1 and let-7f2 miRNA expression in MMCs. In contrast, EphrinA1 activation significantly downregulated H-RAS, K-RAS and N-RAS expression and inhibited MMC proliferation and tumor growth. In MMCs transfected with 2'-O-methyl antisense oligonucleotides to let-7 miRNA, EphrinA1 activation failed to inhibit the proliferative response and tumor growth. In mismatch antisense oligonucleotide-treated MMCs, the proliferation and tumor growth were comparable to untreated proliferating cells. Furthermore, the transfection of MMCs with let-7a miRNA precursor inhibited RAS expression and attenuated MMC tumor growth. Our data revealed that EphrinA1 signaling induces let-7 miRNA expression and attenuates MM tumor growth by targeting RAS proto-oncogene in MMCs.

HPLC determination of dexamethasone in human plasma and its application to an in vitro release study from endovascular stents.

A simple, accurate and precise HPLC assay was developed and validated for determination of dexamethasone in human plasma. Triamcinolone acetonide was used as internal standard (I.S.) and plasma samples were extracted using liquid-liquid extraction with ethyl acetate. Chromatography was performed on a C-18 column with acetonitrile-triple distilled water (28:72% v/v, pH adjusted to 2.3 with phosphoric acid) at a flow rate of 1.2 mL/min and detection wavelength 254 nm. The assay was linear at a concentration range of 0.25-6 microg/mL with recoveries >77%. Precision and accuracy were within the acceptable limits. The method was used to determine dexamethasone release from different material coated endoluminal vascular stents in in vitro human plasma experiments. The results were useful in identifying a good coating material for the stents.

Silicone gel breast implant failure and frequency of additional surgeries: analysis of 35 studies reporting examination of more than 8,000 explants.

Although it is well known that silicone gel breast implants (SGBIs) produce many "local" complications (i.e., pain, hard fibrous capsules, disfigurement, chronic inflammation, implant shell failure) and necessitate frequent surgical revisions, no large cohort retrospective quantitative analysis of clinical data has been reported to date, especially for the prevalence of failures and additional surgeries. Data from 35 different studies that encompass more than 8000 explanted SGBIs have now been analyzed and are reported here. Because examination of a prosthesis when explanted is the definitive method for determining shell integrity, the only studies that were used were ones that reported implant duration, the total number of SGBIs explanted, and the number of SGBIs for which shell rupture or failure ("not intact") was confirmed upon surgical removal. An exponential regression plot of data indicated a direct correlation of implant duration with percent shell failure (r2 = 0. 63 and r = 0.79 ). SGBI failure was found to be 30% at 5 years, 50% at 10 years, and 70% at 17 years. The failure rate was 6% per year during the first 5 years following primary implant surgery. ANOVA comparison of three implant age groups (mean implant durations of 3. 9, 10.2, and 18.9 years) indicated a highly significant statistical correlation of percent failure with implant duration (p < 0.001). Complications necessitating at least one additional surgery occurred for 33% of implants within 6 years following primary implant surgery. Shell failure was found to be an order of magnitude greater than the 4 to 6% rupture prevalence suggested by the AMA Council on Scientific Affairs in 1993, the 0.2 to 1.1% cited by manufacturers at that time, and the 5% rupture that was stated to be "not a safety standard that the FDA can accept."

Prevention of postoperative pericardial adhesions using tissue-protective solutions.

Repeat cardiac surgical procedures are associated with increased technical difficulty and risk because of the previous formation of dense adhesions between the heart and the surrounding tissues. Dilute solutions of sodium hyaluronic acid (NaHA) and carboxymethyl cellulose (CMC) have been shown to prevent postoperative abdominal and pelvic adhesions and could therefore potentially inhibit adhesion formation following cardiac surgery. Adhesion prevention using 0.1% NaHA, 0.4% NaHA, or 0.1% CMC solutions was examined in a canine abrasion/desiccation pericardial adhesion model (5 animals/group) and compared to 10 animals treated with Ringer's lactate (RL) solution alone. The pericardium and heart were coated with 25 ml of test or control solution prior to and after pericardiotomy, after controlled gauze abrasion, after 30 min of desiccation, and prior to closure. At 6 weeks, animals were reexplored and adhesions were scored in a blinded manner by three to four surgeons using a 0-4 scale. Scores of 2 or greater were considered clinically significant. Mean adhesion scores from the left epicardium were 0.0 in animals treated with 0.1% NaHA, 0.6 in animals treated with 0.4% NaHA or 1% CMC, and 2.3 in animals treated with RL (P < 0.05 Duncan's ANOVA). In addition, none of the animals treated with 0.1% NaHA, 20% of the animals treated with 0.4% NaHA, and 20% of the animals treated with 1% CMC had clinically significant adhesions, whereas 80% of animals treated with RL had such adhesions. Sodium hyaluronic acid and CMC solutions, used as tissue coatings during cardiac surgery, inhibit the formation of undesired postoperative adhesions. Application of these biocompatible polymer solutions during surgery could reduce the technical difficulty and risk of repeat cardiac surgical procedures.

Hydrogel contact lens-corneal interactions: a new mechanism for deposit formation and corneal injury.

PURPOSE: In this study, we examined the interactions between hydrogel contact lenses and the cornea, and the role of these interactions in the pathogenesis of interfacial debris formation and the complications of contact lens use. METHODS: We used a corneal abrasion device to simulate the motion of contact lenses on the cornea and the ensuing abrasive interactions. We examined lens and corneal surfaces by Atomic Force Microscopy (AFM), Low Voltage Scanning Electron Microscopy (LVSEM), and optical microscopy (with vital staining of corneas) for unused hydrogel contact lenses, lenses tested in the corneal abrasion device, and worn contact lenses. Young's modulus of hydrogel contact lenses was also measured and compared with the modulus of the human cornea, as reported in the literature. RESULTS: We observed patterns of abrasive damage to the rabbit cornea in vitro caused by corneal interaction with hydrogel contact lenses. Comparison of AFM and SEM of unused lens surfaces with the surfaces of lenses tested in the abrasion device showed dramatic alterations of the contact lens surfaces. Damage to the lenses was also evident by AFM for lenses worn by volunteers. The modulus of hydrogel contact lenses was lower than the modulus of the human cornea. CONCLUSIONS: The surface morphology of hydrogel contact lenses is significantly altered during use. The Young's modulus of the cornea is higher than the modulus of hydrogel contact lenses. These observations suggest a new mechanism for contact lens complications; namely, damage to the contact lens by the cornea as an initial event that produces lens particles and deposits at the lens-cornea interface, followed by corneal abrasion and the onset of other complications.

Examination of contact lens surfaces by Atomic Force Microscope (AFM).

PURPOSE: We evaluated the use of Atomic Force Microscopy (AFM) in examining the surfaces of unused and worn hydrogel contact lenses under natural, fully hydrated conditions. METHODS: Using the AFM contact mode, we examined hydrogel lenses (Acuvue, Surevue, NewVues, CSI Clarity, SeeQuence) that were hydrated. RESULTS: Surface morphologies characteristics of each lens type and wear history were readily observed. The surfaces of worn lenses showed evidence of abrasion and altered morphology. These changes varied with type of contact lens and conditions of use and by site on the lens. CONCLUSIONS: AFM is a very powerful tool for high resolution examination of hydrated contact lens surface structure. The method avoids artifacts due to dehydration and coating which can occur even with low voltage Scanning Electron Microscopy. Significant differences in contact lens surface morphology were observed before and after wear. These observations may be of importance in helping develop improved new lens polymers and ocular solutions.

Prevention of tissue injury and postsurgical adhesions by precoating tissues with hyaluronic acid solutions.

The effectiveness of inhibiting serosal tissue damage and preventing surgical adhesions by precoating tissues with dilute solutions of hyaluronic acid (HA) was evaluated in a rat cecal abrasion model. This study was performed at three independent laboratories using the same protocol. Three hundred and seventy-five adult rats were divided into five treatment groups (125 animals at each study site): 0.1% HA, 0.25% HA, 0.4% HA, phosphate-buffered saline solution (PBS), and no solution. The abdominal cavity of each animal was precoated with 4 ml of test solution or no solution, prior to a controlled abrasion of the cecum. One week later, the animals were sacrificed and adhesions were scored on a 0-4 scale. The data were pooled because no statistical difference was found in the trends at the three study sites. The PBS precoating and no tissue precoating treatment groups had the same high incidence of cecal adhesions, which was significantly higher than the incidence of adhesions in the HA treatment groups. As the HA concentration in the precoating solution increased from 0% (PBS group) to 0.4% HA, the mean incidence of cecal adhesions decreased in a concentration-dependent manner from 1.6 +/- 0.11 to 0.7 +/- 0.09 (P < 0.001). The percentage of animals with no cecal adhesions increased from 11% in the PBS group to 50% in the 0.4% HA treatment group (P < 0.001). In a separate histological study employing 150 rats, HA solutions significantly inhibited serosal tissue damage and ameliorated the inflammatory response due to abrasion and desiccation compared to that with no coating or precoating with buffered saline. Together, these studies demonstrate that tissue precoating with dilute HA solutions reduces damage to serosal tissues during surgery and thereby limits formation of postsurgical adhesions.

Hydrophilic surface modification of metallic endoluminal stents.

PURPOSE: Stainless steel endovascular stents are inherently thrombogenic so that thrombus accumulates on these devices, leading to acute vessel occlusion. A potential solution to this problem is stent surface modification with hydrophilic polymers, which might limit platelet adhesion and reactivity. METHODS: N-vinylpyrrolidone (NVP) and potassium sulfopropyl acrylate (KSPA) hydrophilic monomers were gamma graft polymerized onto 1 cm2 stainless steel slabs and 4 mm Palmaz stainless steel stents. Surface characteristics of modified and plain stainless steel stents were then investigated with contact angle and x-ray photoelectron spectroscopy measurements, and in vitro and in vivo platelet reactivity was assessed as 111Indium platelet accumulation expressed as counts/min/cm2. RESULTS: Surface modification of stainless steel slabs and stents with both NVP and KSPA hydrophilic polymers significantly reduced in vitro platelet adhesion (plain = 2249 +/- 723 counts/min/cm2, NVP = 428 +/- 156 counts/min/cm2, KSPA = 958 +/- 223 counts/min/cm2) and in vivo platelet accumulation after 1 hour of blood flow exposure (plain = 1407 +/- 796 counts/min/cm2, NVP = 426 +/- 175 counts/min/cm2, KSPA = 399 +/- 124 counts/min/cm2. In addition, platelet accumulation on modified stents indexed to plain stents was lowest in KSPA-modified stents (NVP = 79.3% +/- 31.7% of plain, KSPA = 51.2% +/- 36.2% of plain). Surface analysis confirmed surface grafting with both monomers, and SEM documented smoothing of the irregular surfaces of the stainless steel stents after grafting. CONCLUSION: Hydrophilic polymer surface modification of stainless steel stents decreases initial stent surface platelet accumulation, which may decrease the risk of vessel thrombosis associated with the use of these devices.

Evaluation of CMC and HA solutions for adhesiolysis.

Aqueous hyaluronic acid (HA) and carboxymethylcellulose (CMC) solutions were tested as tissue-protective coatings during lysis of surgical adhesions by blunt dissection or electrocautery in a rat cecal abrasion model. Phosphate-buffered saline (PBS) was used as a tissue coating solution in 200 female Sprague-Dawley rats prior to controlled cecal abrasion with a surgical gauze-tipped rotary abrader (four 1.5-cm-diameter areas; 70 g weight/60 revolutions/130 rpm). One-week after this initial cecal abrasion, rats were operated on again and adhesions were scored and lysed. The rats were randomly assigned to receive experimental tissue coating solutions either before (prelysis; n = 160) or after (postlysis; n = 40) adhesiolysis. Animals with prelysis coatings were further divided into blunt dissection or electrocautery adhesiolysis groups and were tested with 2 mL cecal coating of PBS, 0.4% HA, 0.5% CMC, or 1.0% CMC tissue coating solutions (n = 20/group). Rats treated postlysis received 2 mL cecal coating plus 2 mL intraperitoneal instillation of PBS, 1.8, 1.9, or 2.0% CMC. One week after adhesiolysis, rats were operated on again for final adhesion scoring. Prelysis tissue coating with 0.5 or 1.0% CMC solution appeared to inhibit adhesion reformation after blunt dissection, whereas 0.4% HA was not effective in this model. Solutions applied before electrocautery dissection or after blunt dissection were ineffective.

Synthesis, properties, and intratumoral evaluation of mitoxantrone-loaded casein microspheres in Lewis lung carcinoma.

Smooth, round, uniform bovine casein microspheres of 1-5 and 10-20 microns size were readily prepared by a steric stabilization technique previously developed in this laboratory for synthesis of albumin microspheres. The avid phagocytic uptake of casein and albumin microspheres was demonstrated with fluorescein-labelled microspheres using a macrophage-like mouse myelomonocytic leukaemia cell line. Post-synthesis loading of 25% mitoxantrone was achieved for casein microspheres containing 20% polyglutamic acid. Preliminary intratumoural chemotherapy experiments with a mouse Lewis lung carcinoma indicated that mitoxantrone and mitoxantrone-loaded casein-polyglutamic acid microspheres exhibited lower toxicity when administered intratumorally.

Prevention of postoperative abdominal adhesions by tissue precoating with polymer solutions.

Polyvinylpyrrolidone (PVP) and carboxymethylcellulose (CMC) solutions were evaluated in a rat cecal abrasion model to test the effect of these high-molecular-weight hydrophilic polymer solutions on postoperative adhesion formation when used as tissue precoating solutions. Eleven groups of 5-20 animals each were studied including 25 control animals treated with Ringer's lactate (RL) solution. Animals were reoperated at 2 weeks and adhesions were scored according to a 0-4 grading scale. Tissue coating following cecal abrasion failed to inhibit adhesion formation. However, tissue coating with polymer solutions prior to cecal abrasion significantly reduced the formation of post-operative adhesions. Solutions of 1.5% CMC and 5% of a unique gamma-polymerized PVP in RL exhibited the greatest tissue-protective behavior compared to RL controls (P < 0.002). Both CMC and gamma-PVP solutions warrant further investigation as tissue precoatings to inhibit surgical adhesions.

Prevention of postoperative adhesions by precoating tissues with dilute sodium hyaluronate solutions.

Postoperative adhesions (POA), the collagenous connective tissues which form in response to surgical trauma, can be a severe and life threatening surgical complication. However, no generally applicable methods are currently available to mitigate this often serious problem. We have investigated the use of dilute aqueous solutions of sodium hyaluronate (HA) as protective tissue coatings applied prior to surgical manipulation. In a random/blind rat cecal adhesions study conducted at three separate research centers, 0.4 wt% HA in buffered saline gave a three center average of 24% significant adhesions (n = 74) versus 87% for phosphate buffered saline (PBS) controls (n = 69). Histological data suggest that hyaluronic acid tissue precoating minimizes surgical trauma thereby inhibiting POA formation. Clinical studies have been initiated to evaluate the efficacy of tissue precoating with HA solutions in human surgery.

Effect of Ringer's lactate irrigation on the formation of postoperative abdominal adhesions.

Intraabdominal adhesions continue to pose a potentially serious postoperative clinical problem. Reported here is an experiment designed to study any effect that balanced Ringer's lactate (RL) solution may have on intraabdominal adhesion formation. Surgical trauma was induced in mice by controlled gauze abrasion of one side of the abdominal wall; the opposite side was used as a control. RL irrigation was compared with no irrigation. Adhesions were scored on the basis of incidence (%) and severity (on a 0-10 scale). The abraded right peritoneum exhibited 100% adhesions for both the RL group and the nonirrigated group. However, on the side that was not abraded, the nonirrigated group showed only 30% incidence of adhesions and 1.7 +/- 3.3 severity as compared with 100% adhesions and 7.7 +/- 2.2 severity for the RL group. These results suggest the need for further studies to establish the extent to which irrigation with solutions such as Ringer's lactate or saline may enhance formation of postoperative adhesions.

Improved procedure for surface analysis of explanted intraocular lenses by combined light microscopy and scanning electron microscopy.

An improved surface characterization procedure for evaluating explanted intraocular lens (IOL) biocompatibility was developed. The technique combines aqueous hematoxylin-eosin staining for characterizing adherent cells and tissue with subsequent scanning electron microscopy of the same IOL.

Polycarbonate intraocular lenses.

Bisphenol-A polycarbonate has been investigated as an improved polymer for ocular implants, especially for intraocular lenses (IOLs). Polycarbonate properties afford special opportunities for development of tougher, stronger, one-piece IOLs. Autoclave or gamma sterilizability and a higher refractive index may provide additional IOL advantages over polymethylmethacrylate. Implant studies in rabbits have shown polycarbonate IOLs to be well tolerated in the anterior chamber for 2.5 years. Polycarbonate appears promising for new IOLs and other ocular implant applications.