Priming with a very low dose of DNA complexed with cationic block copolymers followed by protein boost elicits broad and long-lasting antigen-specific humoral and cellular responses in mice

Cationic block copolymers spontaneously assemble via electrostatic interactions with DNA molecules in aqueous solution giving rise to micellar structures that protect the DNA from enzymatic degradation both in vitro and in vivo. In addition, we have previously shown that they are safe, not immunogenic and greatly increased antigen-specific CTL responses following six intramuscular inoculations of a very low dose (1 μg) of the vaccine DNA as compared to naked DNA. Nevertheless, they failed to elicit detectable humoral responses against the antigen. To gain further insight in the potential application of this technology, here we show that a shorter immunization protocol based on two DNA intramuscular inoculations of 1 μg of DNA delivered by these copolymers and a protein boost elicits in mice broad (both humoral and cellular) and long-lasting responses and increases the antigen-specific Th1-type T cell responses and CTLs as compared to priming with naked DNA. These results indicate that cationic block copolymers represent a promising adjuvant and delivery technology for DNA vaccination strategies aimed at combating intracellular pathogens.     

Surgical treatment for cholelithiasis.

In a retrospective study, the results of 1,631 consecutive operations for cholelithiasis were analyzed. With an overall mortality rate of 0.18 percent and a reoperation rate of 1.3 percent, conventional cholecystectomy proved to be a safe method. Mortality proved to be age dependent, with a zero mortality rate for patients less than 60 years of age. Choledochotomy had a 13-fold greater mortality rate than simple cholecystectomy (0.92 versus 0.07 percent). For acute cholecystitis, we observed an unusual zero mortality rate, whereas the mortality rate in chronic cholecystitis was 0.2 percent. All three patients who died had an accompanying cirrhosis of the liver. Morbidity, defined as reoperation during the same period of hospitalization, was mainly the result of retained stones after choledochotomy; endoscopic papillotomy was the treatment of choice. Cholecystectomy remains the "gold standard" in the treatment of cholelithiasis.     

Micellar-type complexes of tailor-made synthetic block copolymers containing the HIV-1 tat DNA for vaccine application

A novel class of cationic block copolymers constituted by a neutral hydrophilic poly(ethylene glycol) (PEG) block and a positively charged poly(dimethylamino)ethyl methacrylate block was prepared for delivery of DNA. These block copolymers spontaneously assemble with DNA to give in aqueous medium micellar-like structures. Five of these novel block copolymers (K1-5), differing in the length of both the PEG chain and the linear charge density of the poly(dimethylamino)ethyl methacrylate block, were prepared and analyzed for gene delivery, gene expression and safety. All five block copolymers protected DNA from DNAse I digestion and delivered the DNA into the cell. However, only three of them (K1, K2 and K5) released the DNA at level allowing efficient gene expression into cells. No toxic effects of both the copolymers alone or their DNA complexes were observed in vitro or in mice. In addition, copolymers were scarcely immunogenic. These results indicate that this novel class of cationic block copolymers is safe and possesses the biological characteristics required for DNA delivery, thus, representing promising vehicles for DNA vaccination.     

The learning curve of laparoscopic cholecystectomy and changes in indications: one institutions's experience with 2,650 cholecystectomies

PURPOSE: In a prospective series of 2,650 consecutive patients undergoing cholecystectomy, we analyzed the learning curve since the introduction of laparoscopic cholecystectomy (LC) in terms of operating time, conversion rate, morbidity, mortality, and consequent changes in indications for either laparoscopic or open cholecystectomy (OC). PATIENTS AND METHODS: Between July 1990 and June 1997, LC was performed in 1,929 patients (73%), 203 of whom (7.5%) had to be converted to OC, while 518 patients (19.5%) had primary OC. Patients having LC were predominantly female, younger, with less comorbidity and less complicated gallstone disease than patients having OC. RESULTS: Barring a learning curve during the first 6 months of LC, operating time remained constant at an average of 71 minutes while operating on ever more complex pathologies. The conversion rate decreased from 9.4% to 6.7% during the 7-year period. A relatively constant team of surgeons with growing experience as well as constantly improving technical equipment allowed the complication rate to remain low. The total morbidity of LC was 2.5% (0.1% bile duct injury), that of conversions 5%, and that of OC 12.5%. The mortality was 0 for LC, 0.5% for conversions, and 1% for OC. CONCLUSION: The indications for primary OC decreased from 50% to 8.5% and the indications for LC could be broadened over the years.     

Radiologic and Endoscopic Evaluation for Laparoscopic Adjustable Gastric Banding: Preoperative and Follow-Up

Background: Laparoscopic adjustable silicone gastric banding (LASGB) has replaced vertical banded gastroplasty (VBG) as the most widespread restrictive bariatric operation in Europe. Although these two procedures are similar in principle, the experience concerning the preoperative examinations and follow-up cannot be arbitrarily transferred from VBG to LASGB.The reasons for and consequences drawn from radiologic and endoscopic examinations are described. Methods: From December 1996 to January 2000, 148 patients (84% women, average age 39 years, body weight 127 kg, BMI 45 kg/m²) underwent LASGB. The mean follow-up was 17 months. Upper GI series, abdominal ultrasound, and gastroscopy were done before operation. The postoperative stoma adjustments were performed under radiological observation. All adjustments were analyzed. Results: Preoperative: Of 147 upper GI series, 74 showed hiatal hernia, 2 motility disorders, and 1 an incomplete malrotation. In 104 gastroscopies, 35 reflux and 53 gastritis with 24 Helicobacter pylori infections were found. Postoperative: On average, 2.7 radiological adjustments were done per patient. Until satisfactory satiety and weight reduction, 78% of the patients needed 0-3 adjustments. Besides routine adjustments, an additional 57 upper GI series were done in 35 patients, 44 times with opening of the stoma-diameter. A total of 14 slippages and 4 pouch enlargements were found. A gastroscopy was required in 12 patients. Conclusion: Radiologic and endoscopic examinations before LASGB revealed pathology needing therapy in 42% of the patients and provided important additional information influencing the operative procedure. At an average follow-up of 17 months, 24% of the 148 patients needed unplanned additional upper GI series.     

Endoluminal sonography--preoperative staging of rectal cancer

The endoluminal sonography is a new investigation in staging rectal cancer. In a prospective series the value of the endoluminal sonography is compared with clinical staging and computed tomography. The accuracy in clinical staging, computed tomography and endoluminal sonography was 77%, 76% and 87%, respectively. The reasons for under- and overstaging and the interpretation of perirectal lymph nodes are discussed. The endoluminal sonography is an important new method evaluating the operative procedure of cancers in the lower rectum.     

VEGFR1–mediated pericyte ablation links VEGF and PlGF to cancer-associated retinopathy

VEGF coordinates complex regulation of cellular regeneration and interactions between endothelial and perivascular cells; dysfunction of the VEGF signaling system leads to retinopathy. Here, we show that systemic delivery of VEGF and placental growth factor (PlGF) by protein implantation, tumors, and adenoviral vectors ablates pericytes from the mature retinal vasculature through the VEGF receptor 1 (VEGFR1)-mediated signaling pathway, leading to increased vascular leakage. In contrast, we demonstrate VEGF receptor 2 (VEGFR2) is primarily expressed in nonvascular photoreceptors and ganglion cells. Moreover, blockade of VEGFR1 but not VEGFR2 significantly restores pericyte saturation in mature retinal vessels. Our findings link VEGF and PlGF to cancer-associated retinopathy, reveal the molecular mechanisms of VEGFR1 ligand-mediated retinopathy, and define VEGFR1 as an important target of antiangiogenic therapy for treatment of retinopathy.