In vivo evaluation of pharmacologically active microcarriers releasing nerve growth factor and conveying PC12 cells

Cell therapy will probably become a major therapeutic strategy in the coming years. Nevertheless, few cells survive transplantation when employed as a treatment for neuronal disorders. To address this problem, we have developed a new tool, the pharmacologically active microcarriers (PAM). PAM are biocompatible and biodegradable microparticles coated with cell adhesion molecules, conveying cells on their surface and presenting a controlled delivery of growth factor. Thus, the combined effect of growth factor and coating influences the transported cells by promoting their survival and differentiation and favoring their integration in the host tissue after their complete degradation. Furthermore, the released factor may also influence the microenvironment. In this study, we evaluated their efficacy using nerve growth factor (NGF)-releasing PAM and PC12 cells, in a Parkinson's disease paradigm. After implantation of NGF-releasing or unloaded PAM conveying PC12 cells, or PC12 cells alone, we studied cell survival, differentiation, and apoptosis, as well as behavior of the treated rats. We observed that the NGF-releasing PAM coated with two synthetic peptides (poly-D-lysine and fibronectin-like) induced PC12 cell differentiation and reduced cell death and proliferation. Moreover, the animals receiving this implant presented an improved amphetamine-induced rotational behavior. These findings indicate that PAM could be a promising strategy for cell therapy of neurological diseases and could be employed in other situations with fetal cell transplants or with stem cells.     

Priapism: an avoidable complication of pharmacologically induced erection

Priapism is an alarming complication during treatment of erectile dysfunction with vasoactive drugs, particularly papaverine alone or in combination with phentolamine mesylate. An investigational protocol was designed to identify patients who are more susceptible to priapism after intracavernous injection of papaverine alone or with phentolamine. The protocol was applied in 331 men with impotence of various etiology. The association of a positive response to visual sexual stimulation and penile brachial index of more than 0.8 represented a higher risk for post-injection priapism. We were able to reduce the incidence of this compliance to 1% in the last 101 patients.     

Detrusor hyperreflexia in female urinary incontinence treated pharmacologically.

Detrusor hyperreflexia was found in 54 patients or 14.6% of 369 consecutive patients referred for urinary incontinence and/or genital prolapse during a 2-year period. The dominant symptom was urge incontinence. The urological investigation consisted of a medium fill water cystometry in the supine position. 20 patients (37%) suffered from cerebral or pyramidal nervous disorders. The treatment of choice was pharmacological with parasympatholytica, methantheline bromide (Banthine). The follow-up examinations performed in 33 patients after 6 months treatment showed an improvement rate of 82%. The importance of performing a cystometry in all female patients referred for urinary incontinence is stressed.     

Volume-dependent intracavernous hemodilution during pharmacologically induced penile erections.

The change in the cavernous hematocrit following induction of pharmacological erection by an intracavernous injection of papaverine hydrochloride was documented in normal controls and patients with impotence. Blood samples taken from the penile cavernosa showed a significantly lower hematocrit compared to the systemic venous blood in all normal subjects. The decrease in the cavernous hematocrit was attributable to dilution of the cavernous blood pool by the injected volume of the drug, since this was not observed in erections produced by visual sexual stimulation. It appears that a restriction of the cavernous venous outflow in response to papaverine injection causes sequestration of the diluted blood in the cavernous compartment. The degree of cavernous hemodilution was found to aid in the differential diagnosis and was especially valuable in differentiating patients with arteriogenic impotence from those with venous leakage.     

Studies on intracavernosal VIP levels during pharmacologically induced penile erections

Intracavernosal and peripheral venous vasoactive intestinal polypeptide (VIP) levels were measured in men with predominantly organic or predominantly psychogenic impotence. The measurements were taken at intervals up to 30 min following intracavernosal injections of saline, papaverine hydrochloride and papaverine hydrochloride and phentolamine. Levels were also measured after tactile and visual sexual stimulation and following an intravenous injection of papaverine and phentolamine. A penile erection occurred in all men receiving intracavernosal vasoactive compounds. The mean VIP concentration did not alter significantly in either cavernosal or peripheral venous blood during the erection. Mean VIP concentrations were significantly greater in the neurogenic (all diabetic) group than in the other groups studied. Mean cavernosal and peripheral VIP concentrations did not alter following tactile or visual sexual stimulation and no significant alteration in mean peripheral venous VIP concentration occurred following injection of papaverine and phentolamine. The putative role of VIP in the induction of penile erection has not been elucidated in these studies.     

Oral terbutaline in the management of pharmacologically induced prolonged erection

Prolonged erection and priapism are common complications following intracavernosal injection of vasoactive agents in the management of erectile dysfunction. It is usually treated by intracorporeal drainage and irrigation with sympathomimetic agents. There is no established oral therapy . To study the effect of oral terbutaline on prolonged erection following intracavernosal injection of vasoactive agent, a controlled randomized study was done in 68 patients. Detumescence was achieved in 42 and 15% of the cases with oral terbutaline and placebo, respectively. Results of this study suggest that an initial trial with oral terbutaline for pharmacologically induced prolonged erection may be successful.     

Practice and difficulty evoke anatomically and pharmacologically dissociable brain activation dynamics

Brain activation is adaptive to task difficulty and practice. We used functional MRI to map brain systems activated by an object-location learning task in 24 healthy elderly volunteers each scanned following placebo and two of four active drugs studied. We distinguished a fronto-striatal system adaptive to difficulty from a posterior system adaptive to practice. Fronto-striatal response to increased cognitive load was significantly attenuated by scopolamine, sulpiride and methylphenidate; practice effects were not modulated by these drugs but were enhanced by diazepam. We also found enhancement by methylphenidate, and attenuation by sulpiride, of load response in premotor, cingulate and parietal regions comprising a spatial attention network. Difficulty and practice evoke anatomically and pharmacologically dissociable brain activation dynamics, which are probably mediated by different neurotransmitter systems in humans.     

Methylene blue as a successful treatment alternative for pharmacologically induced priapism

OBJECTIVE: Priapism is defined as prolonged and persistent erection of the penis without sexual stimulation. Etiologies of this condition are numerous. Treatment of priapism varies from a conservative medical to a drastic surgical approach. Recent findings indicate methylene blue (MB), a guanylate cyclase inhibitor, to be a potential inhibitor of endothelial-mediated cavernous relaxation. This prompted us to assess the feasibility, use and effectiveness of MB in the treatment of priapism. METHODS: 12 patients were treated for priapism. Etiologies were: 10 drug-mediated (PGE(1) or papaverine/phentolamine mixture) after corpus cavernosum injection therapy (CCIT); 1 leukemia-induced, and 1 idiopathic high-flow priapism. The age range for all patients was 13-67 years, the average duration of priapism was 5.5 h after CCIT. MB was administered after blood aspiration of the corpora cavernosa. 5 ml of MB was injected intracavernously (i.c.) and left for 5 min. MB was then aspirated and the penis compressed for an additional 5 min. RESULTS: All patients with CCIT-induced priapism were cured with MB alone. The 2 patients who did not respond to MB underwent i.c. phenylephrine administration and embolization of the pudendal artery, respectively. The etiology and duration of priapism were the strongest predictors for success with i.c. administered MB. The primary side effects were a transient burning sensation and blue discoloration of the penis on injection of MB. The initial baseline erectile status was restored in all patients cured by MB. CONCLUSION: These results confirm that MB is a safe and highly effective treatment agent for short-term pharmacologically induced priapism. The application of MB shows virtually no significant side effects compared to the systemic and local complications induced by alpha-adrenergic agonists.     

勃起功能障碍病人阴茎海绵体血浆中降钙素基因相关肽含量的研究

目的　了解阴茎勃起前后 ,阴茎海绵体内血浆中降钙素基因相关肽 (CGRP)含量。方法　对不同组受检者行海绵体内注射生理盐水、盐酸罂粟碱、盐酸罂粟碱和酚妥拉明混合液。每次注药间隔时间超过 3 0分钟 ,注药前后取海绵体内血液测定CGRP含量。结果　正常人及各类ED在海绵体内注射血管活性药物后阴茎均发生勃起。在阴茎勃起过程中海绵体内血浆CGRP含量升高 (P <0 .0 5 )。周围静脉注射罂粟碱和酚妥拉明混合液的受检者 ,注药后周围静脉血浆CGRP含量无变化 (P >0 .0 5 )。结论　CGRP是参与人类阴茎勃起的重要神经递质     

High-resolution depth electrode localization and imaging in patients with pharmacologically intractable epilepsy

Localization and targeting of depth electrodes in specific regions of the human brain is critical for accurate clinical diagnoses and treatment as well as for neuroscientific electrophysiological research. By using high-resolution magnetic resonance imaging combined with 2D computational unfolding, the authors present a method that improves electrode localization in the medial temporal lobe. This method permits visualization of electrode placements in subregions of the hippocampus and parahippocampal gyrus, allowing for greater specificity in relating electrophysiological and anatomical features in the human medial temporal lobe. Such methods may be extended to therapeutic procedures targeting specific neuronal circuitry in subfields of structures deep in the human brain.     

Regional coronary blood flow in awake resting and pharmacologically stressed dogs.

To determine the transmural distribution of blood flow in the major regions of the heart we used the radioactive microsphere method to measure flow in multiple layers of the septum and right and left ventricle in four dogs. Studies were done in awake dogs in the resting, and isoproterenol infusion states, and in the sedated state during methoxamine- and propranolol-induced left ventricular failure. The transmural distribution of right ventricular flow was uniform at rest redistributed to higher midwall flow during isoproterenol infusion, and redistributed to a near linear decrease in flow from the endocardium to epicardium during ventricular failure. Left ventricular transmural flow decreased slightly from the endocardium to epicardium at rest, was near uniform during isoproterenol, but in failure there was a redistribution such that subendocardial flow was approximately twice subepicardial with a near linear decrease across the myocardium. Septal flow distribution tended to follow the absolute right and left ventricular flows. These results demonstrate that the transmural distribution of myocardial blood flow in septum right and left ventricles varies within and between hearts at rest and during isoproterenol and pharmacologically induced left ventricular failure.     

Controlled intermittent asystole cardiac therapy induced by pharmacologically potentiated vagus nerve stimulation in normal and hibernating myocardium

BACKGROUND: Pharmacologically potentiated electrical stimulation of the right vagus nerve achieves controlled intermittent asystole cardiac therapy. The present study examined pathophysiologic consequences of repetitive intermittent asystoles on contractile function, myocardial blood flow, and vagus nerve function and morphology. METHODS: Open-chest anesthetized canines, with either normal left anterior descending (LAD) coronary arteries (n = 8) or severely stenotic LADs (n = 8), received pharmacologic pretreatment with pyridostigmine (0.5 mg/kg), propranolol (80 microg/kg), and verapamil (50 microg/kg) before vagus nerve stimulation. Time-matched control animals with normal (n = 4) or severely stenotic LADs (n = 6) received drugs but no vagus nerve stimulation. The vagus nerve was stimulated for 12 seconds ("on") and rested for 15 seconds ("off"). This algorithm was repeated for 15 on-off cycles, simulating using controlled intermittent asystole during the placement of 15 sutures in a distal coronary anastomosis. This 15-cycle sequence was repeated twice more, simulating a three-vessel bypass. RESULTS: Normal coronary arteries: Ninety minutes after three sets of controlled intermittent asystole, LAD blood flow was unchanged from base line (36.6 +/- 4.5 versus 33.0 +/- 4.2 mL/min, p = 0.4), and global left ventricular performance (impedance catheter, end-systolic pressure-volume relations) was similar to baseline (7.4 +/- 1.2 versus 7.2 +/- 1.0 mm Hg/mL, p = 0.1). Left anterior descending coronary artery stenosis model: Ninety minutes after CIA, there were no significant differences versus control animals in regional LAD blood flow (27 +/- 4 versus 29 +/- 5 mL/min, p = 0.4) or fractional shortening of LAD myocardium (sonomicrometry; 6.2% +/- 1.8% versus 5.4% +/- 1.2%, p = 0.1). Vagus nerve conduction and morphology were unchanged from baseline. CONCLUSIONS: Repetitive controlled intermittent asystole does not impair poststimulation coronary blood flow, cardiac contractile function, or vagus nerve function. Controlled intermittent asystole may be useful to facilitate off-pump or endoscopic coronary artery bypass grafting.     

Long-term survival of limb allografts induced by pharmacologically conditioned, donor alloantigen-pulsed dendritic cells without maintenance immunosuppression

BACKGROUND: We showed recently that limb allograft survival could be enhanced by administration of alloantigen (Ag)-pulsed immature dendritic cells (DC) after transplantation. Since indefinite graft survival was not achieved, we have further modified the DC by pharmacologic (rapamycin; Rapa) conditioning and ascertained their influence on graft survival, without continued immunosuppressive therapy. METHODS: We compared the ability of donor Ag-pulsed, Rapa-conditioned rat myeloid DC (Rapa DC) and control DC (CTR DC) to inhibit alloreactive T-cell responses after limb transplantation in antilymphocyte serum (ALS)-treated recipients given a short postoperative course of cyclosporine (CsA). RESULTS: Both DC populations expressed similar levels of major histocompatibility complex (MHC) II, CD40 and CD54, but Rapa DC expressed lower CD86. After toll-like receptor activation, both populations produced minimal interleukin (IL)-12p70, but Rapa DC secreted lower levels of IL-6 and IL-10. The capacity of DCs to stimulate T-cell proliferation in mixed leukocyte reactions was very low. Pulsing of the DC with donor Ag did not alter their phenotype or function. Interestingly, posttransplant administration of donor Ag-pulsed Rapa DC to rats given perioperative ALS and 21 days CsA significantly delayed graft rejection and promoted long-term (>125 days) graft survival. AlloAg-pulsed Rapa DC induced T-cell hyporesponsiveness and promoted the generation of IL-10-secreting CD4 T cells upon ex vivo challenge. CONCLUSIONS: Infusion of donor Ag-pulsed, Rapa-conditioned DC after composite tissue transplantation can prevent rejection of the grafts, including skin, across a full MHC mismatch and in the absence of continued immunosuppressive therapy.     

Controlled intermittent asystole cardiac therapy induced by pharmacologically potentiated vagus nerve stimulation in normal and hibernating myocardium

Background

Pharmacologically potentiated electrical stimulation of the right vagus nerve achieves controlled intermittent asystole cardiac therapy. The present study examined pathophysiologic consequences of repetitive intermittent asystoles on contractile function, myocardial blood flow, and vagus nerve function and morphology.

Methods

Open-chest anesthetized canines, with either normal left anterior descending (LAD) coronary arteries (n = 8) or severely stenotic LADs (n = 8), received pharmacologic pretreatment with pyridostigmine (0.5 mg/kg), propranolol (80 μg/kg), and verapamil (50 μg/kg) before vagus nerve stimulation. Time-matched control animals with normal (n = 4) or severely stenotic LADs (n = 6) received drugs but no vagus nerve stimulation. The vagus nerve was stimulated for 12 seconds (“on”) and rested for 15 seconds (“off”). This algorithm was repeated for 15 on-off cycles, simulating using controlled intermittent asystole during the placement of 15 sutures in a distal coronary anastomosis. This 15-cycle sequence was repeated twice more, simulating a three-vessel bypass.

Results

Normal coronary arteries: Ninety minutes after three sets of controlled intermittent asystole, LAD blood flow was unchanged from base line (36.6 ± 4.5 versus 33.0 ± 4.2 mL/min, p = 0.4), and global left ventricular performance (impedance catheter, end-systolic pressure-volume relations) was similar to baseline (7.4 ± 1.2 versus7.2 ± 1.0 mm Hg/mL, p = 0.1). Left anterior descending coronary artery stenosis model: Ninety minutes after CIA, there were no significant differences versus control animals in regional LAD blood flow (27 ± 4 versus 29 ± 5 mL/min, p = 0.4) or fractional shortening of LAD myocardium (sonomicrometry; 6.2% ± 1.8% versus 5.4% ± 1.2%, p = 0.1). Vagus nerve conduction and morphology were unchanged from baseline.

Conclusions

Repetitive controlled intermittent asystole does not impair poststimulation coronary blood flow, cardiac contractile function, or vagus nerve function. Controlled intermittent asystole may be useful to facilitate off-pump or endoscopic coronary artery bypass grafting.