PPV Group Research Articles

Microincision Vitrectomy Surgery and Intravitreal Bevacizumab as a Surgical Adjunct to Treat Diabetic Traction Retinal Detachment

To investigate the feasibility and efficacy of microincision vitrectomy surgery (MIVS) combined with intravitreal bevacizumab (IVB) as a surgical adjunct for treating traction retinal detachment (TRD) secondary to severe proliferative diabetic retinopathy (PDR). Retrospective, comparative, consecutive, interventional case series. Seventy-one eyes of 59 consecutive patients who underwent primary vitrectomy for diabetic TRD and were followed up for more than 6 months after surgery. Eyes that received IVB (1 mg) as a preoperative adjunct followed by MIVS (IVB/MIVS group) from November 2005 through December 2007 were compared with eyes that underwent conventional 20-gauge pars plana vitrectomy (20-g PPV group) from September 2003 through October 2005. Primary and ultimate anatomic success, intraoperative and postoperative complications, and final visual success with at least 6 months of follow-up. This series included 38 eyes (33 patients) in the IVB/MIVS group and 33 eyes (26 patients) in the 20-g PPV group. The primary and ultimate anatomic success rates (95% vs. 91% and 100% in both groups, respectively) and the mean visual acuity changes did not differ significantly between groups; the surgical time and intraoperative bleeding in the IVB/MIVS group decreased significantly compared with the 20-g PPV group (P<0.001). The rate of visual improvement of 3 lines or more at the 6-month follow-up was 68% in the IVB/MIVS group and 49% in the 20-g PPV group, respectively. Progression of the preexisting TRD after IVB occurred in 7 eyes (18%). Absence of previous laser photocoagulation (P = 0.025) and the presence of a ring-shaped fibrovascular membrane (P = 0.013) were relevant findings in eyes with these IVB-induced complications. Intravitreal bevacizumab plus MIVS offers comparable anatomic success compared with conventional 20-gauge PPV in patients with TRD resulting from severe PDR. This technique shortens the surgical time with fewer intraoperative complications and favorable visual recovery. However, caution should be taken because of rapid progression of the preexisting TRD after IVB in some patients. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Immunological efficacy of a prime-boost pneumococcal vaccination in HIV-infected adults

To evaluate whether a strategy combining a prime with a 7-valent conjugate pneumococcal vaccine (PCV) followed by a boost with the 23-valent polysaccharide vaccine (PPV) would improve immunogenicity against Streptococcus pneumoniae polysaccharides in HIV-infected patients. Randomized controlled phase II trial. Two-hundred and twelve patients with CD4 cell counts of 200-500 cells/mul and HIV RNA< 4 log10 copies/ml, regardless of antiretroviral treatment, were randomized to receive either PCV at week 0 and PPV at week 4 (n = 106) or PPV alone at week 4 (n = 106). The proportion of responders to 0, 1-2, 3-4, 5-7 serotypes shared by the two vaccines was evaluated at week 8 and compared using a proportional odds model allowing for adjustment for CD4 cell count, HIV RNA and antiretroviral treatment. At week 8, the profile of response was better in the prime-boost group compared to the PPV group, as determined by the frequency of patients who reached both a twofold increase of serotype-specific IgG levels and IgG level >/= 1 mug/ml [proportional odds ratio (OR), 2.09; 95% confidence interval (CI), 1.25-3.51; P = 0.005]. No differences in responders were found 4 weeks after PCV or PPV alone, suggesting that PCV primed for response to PPV. Early differences between groups remained significant at week 24 (proportional OR, 2.14; 95% CI, 1.30-3.54; P = 0.003). In a setting of practical care, a PCV prime-PPV boost strategy enhances the frequency, breadth and magnitude of antibody responses against SPP in HIV-infected adults.

Open lung ventilation improves gas exchange and attenuates secondary lung injury in a piglet model of meconium aspiration.

Previous studies failed to show clear benefits of high-frequency ventilation compared with conventional positive pressure ventilation (PPV(CON)) in experimental meconium aspiration syndrome. However, none of these studies applied an open lung ventilation strategy (OLC), which aims to reduce intrapulmonary shunt due to alveolar collapse. We hypothesized that, if combined with an open lung strategy, both high-frequency oscillatory ventilation (HFOV(OLC)) and positive pressure ventilation (PPV(OLC)) would improve gas exchange and attenuate ventilator-induced lung injury in experimental meconium aspiration syndrome. Prospective, randomized animal study. Research laboratory of a large university. Forty-two newborn piglets. Thirty minutes after intratracheal meconium instillation, 36 newborn piglets were assigned to one of three ventilation groups-PPV(OLC), HFOV(OLC), or PPV(CON)-and ventilated for 5 hrs. In both OLC groups, collapsed alveoli were actively recruited and thereafter stabilized using the lowest possible airway pressures. During PPV(CON), ventilator settings were adjusted to prevent critical hypoxia (Pao2 <60 torr [8 kPa]). Six animals served as saline controls. Compared with the PPV(CON) group, arterial oxygenation and lung mechanics were superior in both OLC groups and the saline controls. Analysis of the bronchoalveolar lavage fluid obtained after 5 hrs of ventilation showed increased myeloperoxidase activity in the PPV(CON) group compared with both OLC groups and saline controls. Alveolar protein influx was not different between the groups. Histologic analysis revealed a higher lung injury score in the PPV(CON) group compared with the PPV(OLC) and the HFOV(OLC) groups. Application of the OLC during PPV and HFOV is feasible in experimental meconium aspiration syndrome and results in superior oxygenation and less ventilator-induced lung injury compared with PPV(CON).

Nicotiana benthamiana plants transgenic for PPV-SWC coat protein are resistant to PPV infection

Two constructs containing the coat protein gene (CP) of PPV-SwC – in (+) and (–) sense – were obtained and used to transform Nicotiana benthamiana plants via Agrobacterium tumefaciens. Transformed lines were analysed for the integration of the CP gene by PCR and Southern blot. Sixty transgenic lines were selected. Expression of CP gene was investigated by immuno-western blot using a monoclonal antibody specific for PPV-SwC. Various levels of CP expression were detected in transgenic plants. R1 lines were challenged with the homologous virus and with isolates belonging to D, M and EA PPV groups. A variable degree of resistance was obtained, going from complete susceptibility to immunity. Susceptible plants showed a slight delay in symptoms expression when compared to non transformed control. No correlation was established by CP expression level and observed resistance.

Immunogenicity and reactogenicity of the Biken acellular pertussis vaccine in young adults

To assess the reactogenicity and immunogenicity of the Biken acellular pertussis vaccine (Pa) following administration of a single vaccine dose to young adults with or without a history of prior pertussis immunization, 104 healthy, male and female adults without primary pertussis immunization were enrolled in Mainz (former West Germany; “not previously pertussis vaccinated”, N-PPV-group); in parallel, 103 adults with a history of having received ≥four doses of a combined diphtheria-, tetanus-toxoid, whole-cell pertussis vaccine (DTwP) were enrolled in Magdeburg (former East Germany; “previously pertussis-vaccinated”, PPV-group). Large areas of redness (>20 mm) were seen in 2.9%/1.0% of subjects in the N-PPV/PPV group, and a large swelling was seen in 6.8%/1.0%, respectively. As compared to baseline concentrations, antibody titers to PT and FHA were 77-(PT)/64-(FHA) (N-PPV group) and 94-(PT)/126-(FHA) fold (PPV group) higher. The study vaccine was safe and induced infrequent and mostly mild, local and general symptoms that all resolved spontaneously; it was highly immunogenic in adults, whether or not they had been previously vaccinated with DTwP.

Blue Lasing in Poly(Octanedioxy-Co-DMPPV) Copolymer Microcavity

Poly[octanedioxy-co-DMPPV] copolymer was synthesized to fabricate the microcavity device. The blue emitting polymers consist of strictly alternating conjugated PPV and non-conjugated alkyl group. The microcavity based on distributed Bragg reflector (DBR) and the spin-coated copolymer thin film shows promising lasing characteristics. A strong blue emission at 437.9 nm with 6.5 nm line width was due to cavity enhancement and large gain from the copolymer layer. Third harmonic of Nd:YAG laser(355 nm) was used as a pulsed pump source and its energy threshold for lasing was around few microjoules per pulse. The lasing characteristics strongly depended on the microcavity structure and copolymer film processing. Q factor was calculated to be 67 and the operational lifetime of over 7×105 pulses was observed.

Isoproterenol attenuates high vascular pressure-induced permeability increases in isolated rat lungs.

To separate the contributions of cellular and basement membrane components of the alveolar capillary barrier to the increased microvascular permeability induced by high pulmonary venous pressures (Ppv), we subjected isolated rat lungs to increases in Ppv, which increased capillary filtration coefficient (Kfc) without significant hemorrhage (31 cmH2O) and with obvious extravasation of red blood cells (43 cmH2O). Isoproterenol (20 microM) was infused in one group (Iso) to identify a reversible cellular component of injury, and residual blood volumes were measured to assess extravasation of red blood cells through ruptured basement membranes. In untreated lungs (High Ppv group), Kfc increased 6.2 +/- 1.3 and 38.3 +/- 15.2 times baseline during the 31 and 43 cmH2O Ppv states. In Iso lungs, Kfc was 36.2% (P < 0.05) and 64.3% of that in the High Ppv group at these Ppv states. Residual blood volumes calculated from tissue hemoglobin contents were significantly increased by 53-66% in the high Ppv groups, compared with low vascular pressure controls, but there was no significant difference between High Ppv and Iso groups. Thus isoproterenol significantly attenuated vascular pressure-induced Kfc increases at moderate Ppv, possibly because of an endothelial effect, but it did not affect red cell extravasation at higher vascular pressures.

Role of lung injury in the pathogenesis of hyaline membrane disease in premature baboons.

To test the hypothesis that hyaline membrane disease (HMD) has a multifactorial etiology in which barotrauma plays a major role, we compared the immediate institution of high-frequency oscillatory ventilation (HFOV; 15 Hz, n = 5) with positive-pressure ventilation with positive end-expiratory pressure (PPV; n = 7) in premature baboons (140-days gestation) with HMD. Measurements of ventilation settings and physiological parameters were obtained and arterial-to-alveolar O2 (PaO2-to-PAO2) ratio and oxygenation index [(PaO2/PAO2)-to-mean airway pressure ratio (IO2)] were calculated. At death (24 h), static pressure-volume (PV) curves were performed, and phospholipids (PL) and platelet-activating factor (PAF) were measured in lung lavage fluid. Morphological inflation patterns were analyzed using a panel of standards. By design, mean airway pressure was initially higher (19 vs. 13 cmH2O) in the HFOV animals. PaO2-to-PAO2 ratio and IO2 progressively deteriorated in the PPV animals and then stabilized at significantly lower levels than with HFOV. PV curves from HFOV animals had significant increases in lung volume at maximum distending pressure, deflation volume at 10 cmH2O, and hysteresis area compared with PPV, which showed no hysteresis. Seven of seven PPV and only one of five HFOV animals had morphological findings of HMD. PL amount and composition in both groups were consistent with immaturity, even though the quantity was significantly greater in the PPV group. PAF was present (greater than or equal to 0.10 pmol) in six of seven PPV and in the only HFOV animal with HMD. We conclude that HFOV protected PL-deficient premature baboons from changes in gas exchange, lung mechanics, and morphology typical of HMD in this model.(ABSTRACT TRUNCATED AT 250 WORDS)