Vascular endothelial growth factor expression and vascularity in renal allograft biopsies

BACKGROUND: Vascular endothelial growth factor (VEGF) expression influences tubular repair and promotes angiogenesis. The aim of the present study was to determine the relation of VEGF expression and cortical vascularity with renal pathological changes and clinical parameters in allograft biopsies. MATERIALS AND METHODS: Sections from 50 renal allograft biopsies were evaluated by streptavidine-biotin immunohistochemistry by primary antibodies against VEGF and CD34. Cortical tubulointersititial (TI) VEGF expression was scored by light microscopic examination considering intensity and density. Glomerular expression was scored as 0: no staining; 1: faint staining in less than 50% of glomeruli; 2: moderate to strong staining in more than 50% of glomeruli. We determined the number of vessels per cortical high power field (Nves) highlighted by CD34 staining. The clinical and pathological features were retrieved from patient files. RESULTS: Nves was decreased with interstitial fibrosis (IF): 56.3 +/- 3.7; 53.3 +/- 9.8, 46.6 +/- 10.5, 36.75 +/- 1.89 for cases with no IF to mild, moderate, and severe forms, respectively (P < .000). There was increased TI VEGF expression: 1.86 +/- 2.12, 5.8 +/- 3.1, 5.85 +/- 4.4, 10.25 +/- 2.06, respectively (P = .004). The NVes values were not different for cases with high and low to negative VEGF expression scores. There was a negative correlation between Nves values and creatinine at the time of biopsy and time from transplantation to biopsy (r = -.325, P = .024 and r = -.294, P = .038, respectively). Nves and VEGF scores were not different when acute rejection scores or cyclosporine toxicity were considered (P > .05), while Nves were significantly different for chronic allograft nephropathy scores (P = .05). CONCLUSIONS: Chronic renal changes seemed to be associated with decreased cortical vascularity in renal allografts, while the TI VEGF expression was increased. In contrast Nves was not increased with VEGF expression in this series. It seems that along with VEGF, other factors are required for protection against vascular reduction. The aging of the allograft is also a negative influence on cortical vascularity.     

Pedicled rectus abdominis muscle flap wrapped around the penis for enhanced urethral pressure: an experimental study in dogs

PURPOSE: It was the aim of this study to investigate the possibility of pedicled rectus abdominis muscle fascial flap wrapped around the penis for enhanced urethral pressure in dogs. MATERIALS AND METHODS: Ten adult male Beagle dogs underwent a procedure in which surrounding tissue of the penis at the site of the bulbomembranous urethra was dissected and a pedicled rectus abdominis muscle fascial flap was wrapped around the penis. Profilometry of the urethral pressure was carried out before, during and after the operation in all dogs. RESULTS: Before the operation, the mean maximal urethral pressure (MUP) was 48.9 +/- 11 cm H(2)O, and the mean MUP was 78.3 +/- 20.5 cm H(2)O after the penis was surrounded by a rectus muscle flap. There was a significant difference (t = 4.99, p = 0.0007). Ten weeks after the operation, the mean MUP was 88.3 +/- 22.4 cm H(2)O, which was significantly higher than that before the operation (t = 6.0584, p = 0.0002). CONCLUSIONS: A pedicled rectus abdominis muscle fascial flap wrapped around the penis can raise the urethral pressure. This provided an experiment basis for treating male urinary incontinence with a pedicled rectus muscle flap.     

Carboxymethyl xanthan microparticles as a carrier for protein delivery

Xanthan gum (XG) was derivatized to sodium carboxymethyl xanthan gum (SCMXG) and then cross-linked with aluminium ions (Al(+3)) to prepare BSA-loaded microparticles (MPs) from a completely aqueous environment. The derivatized gum was characterized by various physical methods. Discrete and spherical BSA-loaded MPs were obtained from SCMXG solution, the pH of which was adjusted to 6 and 7 and the BSA entrapment efficiency was found to reach as high as 82%. The protein release in acidic dissolution medium was faster than that in alkaline dissolution medium and was accounted for the higher swelling ratio of the MPs in acidic environment. Moreover, the pH of the gum solution used to prepare the MPs also influenced the swelling and consequently protein release considerably.     

Drug-eluting implants for osteomyelitis

Osteomyelitis, an inflammatory process accompanied by bone destruction, is caused by infective microorganisms. The high success rates of antimicrobial therapy by conventional routes of administration in controlling most infectious diseases have not yet been achieved with osteomyelitis for several reasons. Local and sustained availability of drugs have proven to be more effective in achieving prophylactic and therapeutic outcomes. This review introduces osteomyelitis--its prevalence and pathogenesis, the present options for drug delivery and their limitations, and the wide range of carrier materials and effective drug choices, with major focus on the pharmaceutical concepts involved in drug delivery system design and development. With increasing numbers of orthopedic surgeries and the advent of combination devices that provide support and deliver drugs, local drug delivery for osteomyelitis is a topic of importance for both social and commercial interests.     

Lipoplex and peptide-based strategies for the delivery of steric-block oligonucleotides

Synthetic oligonucleotides offer interesting prospects for the control of gene expression but clinical applications have been severely limited by their poor bioavailability. Cationic lipids have been widely used for the delivery of charged oligonucleotide (ON) analogues but most of the commercial formulations are toxic and poorly stable in the presence of serum proteins. We have developed a DOGS/DOPE liposome formulation named DLS (for delivery liposomal system), that allows for the efficient nuclear delivery of negatively charged antisense ON analogues as monitored by fluorescence microscopy and by their ability to correct deficient pre-mRNA splicing, even in serum-supplemented cell culture. Uncharged DNA mimics such as peptide nucleic acids (PNA), or phosphorodiamidate morpholino (PMO) ON are particularly interesting for their high metabolic stability and affinity for complementary RNA targets but they cannot be delivered with cationic lipids. Cell penetrating peptides (CPP), such as Tat or penetratin, have been used widely as conjugates for the delivery of various biomolecules and might be appropriate for neutral ON analogues. However, entrapment within endocytic vesicles severely limits the efficiency of PNA delivery by CPPs in the absence of endosomolytic drugs, such as chloroquine. The conjugation of new arginine-rich CPPs to PNA allows efficient nuclear delivery in the absence of chloroquine as monitored in a splicing correction assay. Both strategies have their advantages but DLS-mediated delivery remains more efficient than CPP delivery for the nuclear targeting of splice correcting ON analogues in vitro.     

Spatial Variability of Trace Metals and Inorganic Nutrients in Surface Waters of Todos Santos Bay,México in the Summer of 2005 During a Red Tide Algal Bloom

Dissolved and particulate metals (Ag, Cd, Co, Cu, Ni, and Zn) and nutrients (PO₄, NO₃, and H₄SiO₄) were measured in Todos Santos Bay (TSB) in August 2005. Two sources producing local gradients were identified: one from a dredge discharge area (DDA) and another south of the port and a creek. The average concentrations of dissolved Cd and Zn (1.3 and 15.6 nM, respectively) were higher by one order of magnitude than the surrounding Pacific waters, even during upwelling, and it is attributed to the presence of a widespread and long-lasting red tide coupled with some degree of local pollution. A clear spatial gradient (10 to 6 pM), from coast to offshore, of dissolved Ag was evident, indicating the influence of anthropogenic inputs. The particulate fraction of all metals, except Cu, showed a factor of ~3 decrease in concentrations from the DDA to the interior of the bay. The metal distributions were related to the bay’s circulation by means of a numerical model that shows a basically surface-wind-driven offshore current with subsurface compensation currents toward the coast. Additionally, the model shows strong vertical currents over the DDA. Principal component analysis revealed three possible processes that could be influencing the metal concentrations within TSB: anthropogenic inputs (Cd, Ag, and Co), biological proceses (NO₃, Zn, and Cu), and upwelling and mixing (PO₄, H₄SiO₄, Cd, and Ni). The most striking finding of this study was the extremely high Cd concentrations, which have been only reported in highly contaminated areas. As there was a strong red tide, it is hypothesized that the dinoflagellates are assimilating the Cd, which is rapidly remineralized and being concentrated on the stratified surface layers.     

Dopamine D2 receptor stimulation inhibits angiotensin II-induced hypertrophy in cultured neonatal rat ventricular myocytes

1. Myocardial hypertrophy is a common pathological change that accompanies cardiovascular disease. Dopamine D2 receptors have been demonstrated in cardiovascular tissues. However, the pathophysiological involvement of D2 receptors in myocardial hypertrophy is unclear. Therefore, the effects of the D2 receptor agonist bromocriptine and the D2 receptor antagonist haloperidol on angiotensin (Ang) II- or endothelin (ET)-1-induced hypertrophy of cultured neonatal rat ventricular myocytes were investigated in the present study. 2. Protein content and protein synthesis, determined by examining [(3)H]-leucine uptake, were used as estimates of cardiomyocyte hypertrophy. The expression of D2 receptor protein in neonatal rat ventricular myocytes was determined using western blotting. Changes in [Ca(2+)](i) in cardiomyocytes were observed by laser scanning confocal microscopy. 3. Angiotensin II and ET-1, both at 10 nmol/L, induced myocyte hypertrophy, as demonstrated by increased protein content and synthesis, [Ca(2+)](i) levels, protein kinase C (PKC) activity and phosphorylation of extracellular signal-regulated kinase, c-Jun N-terminal kinase and mitogen-activated protein kinase (MAPK) p38 (p38). Concomitant treatment of cells with 10 nmol/L AngII plus 10 micromol/L bromocriptine significantly inhibited cardiomyocyte hypertrophy, MAPK phosphorylation and PKC activity in the membrane, as well as [Ca(2+)](i) signalling pathways, compared with the effects of AngII alone. In addition, 10 micromol/L bromocriptine significantly inhibited cardiomyocyte hypertrophy induced by 10 nmol/L ET-1. However, pretreatment with haloperidol (10 micromol/L) had no significant effects on cardiomyocyte hypertrophy induced by either AngII or ET-1. 4. In conclusion, D2 receptor stimulation inhibits AngII-induced hypertrophy of cultured neonatal rat ventricular myocytes via inhibition of MAPK, PKC and [Ca(2+)](i) signalling pathways.     

Oestrogen confers cardioprotection by suppressing Ca2+/calmodulin-dependent protein kinase II

Background and purpose:

Oestrogen confers cardioprotection by down-regulating the β₁-adrenoceptor and suppressing the expression and activity of protein kinase A. We hypothesized that oestrogen may also protect the heart by suppressing Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), another signalling messenger activated by the β₁-adrenoceptor, that enhances apoptosis.

Experimental approach:

We first determined the expression of CaMKII in the heart from sham and ovariectomized rats with and without oestrogen replacement. We then determined the effects of CaMKII inhibition (KN93, 2.5 µmol·L⁻¹) in the presence or absence of 10⁻⁷ mol·L⁻¹ isoprenaline, a non-selective β-adrenoceptor agonist. We also determined the percentage apoptosis in myocytes from rats in each group with or without β-adrenoceptor stimulation.

Key results:

Both CaMKIIδ and phosphorylated CaMKII were up-regulated in the hearts from ovariectomized rats, and they were restored to normal by oestrogen replacement. The infarct size and lactate dehydrogenase release were significantly greater after ovariectomy. Similarly, cardiac contractility, the amplitude of the electrically induced intracellular Ca²⁺ transient and the number of apoptotic cells were also greater in ovariectomized rats upon ischaemia/reperfusion in the presence or absence of isoprenaline. Most importantly, the responses to ischaemic insult in ovariectomized rats were reversed not only by oestrogen replacement, but by blockade of CaMKII with KN93.

Conclusions and implications:

Oestrogen confers cardioprotection at least partly by suppressing CaMKIIδ. This effect of oestrogen on CaMKII is independent of the β-adrenoceptor and occurs in addition to down-regulation of the receptor.