Dopamine, kidney, and hypertension: studies in dopamine receptor knockout mice

Dopamine is important in the pathogenesis of hypertension because of abnormalities in receptor-mediated regulation of renal sodium transport. Dopamine receptors are classified into D₁-like (D₁, D₅) and D₂-like (D₂, D₃, D₄) subtypes, all of which are expressed in the kidney. Mice deficient in specific dopamine receptors have been generated to provide holistic assessment on the varying physiological roles of each receptor subtype. This review examines recent studies on these mutant mouse models and evaluates the impact of individual dopamine receptor subtypes on blood pressure regulation.     

Click chemistry reactions in medicinal chemistry: applications of the 1,3-dipolar cycloaddition between azides and alkynes

In recent years, there has been an ever-increasing need for rapid reactions that meet the three main criteria of an ideal synthesis: efficiency, versatility, and selectivity. Such reactions would allow medicinal chemistry to keep pace with the multitude of information derived from modern biological screening techniques. The present review describes one of these reactions, the 1,3-dipolar cycloaddition ("click-reaction") between azides and alkynes catalyzed by copper (I) salts. The simplicity of this reaction and the ease of purification of the resulting products have opened new opportunities in generating vast arrays of compounds with biological potential. The present review will outline the accomplishments of this strategy achieved so far and outline some of medicinal chemistry applications in which click-chemistry might be relevant in the future.     

Integrated electromyogram and eye-gaze tracking cursor control system for computer users with motor disabilities

This research pursued the conceptualization, implementation, and testing of a system that allows for computer cursor control without requiring hand movement. The target user group for this system are individuals who are unable to use their hands because of spinal dysfunction or other afflictions. The system inputs consisted of electromyogram (EMG) signals from muscles in the face and point-of-gaze coordinates produced by an eye-gaze tracking (EGT) system. Each input was processed by an algorithm that produced its own cursor update information. These algorithm outputs were fused to produce an effective and efficient cursor control. Experiments were conducted to compare the performance of EMG/EGT, EGT-only, and mouse cursor controls. The experiments revealed that, although EMG/ EGT control was slower than EGT-only and mouse control, it effectively controlled the cursor without a spatial accuracy limitation and also facilitated a reliable click operation.     

Successful management of deep facial burns in a patient with extensive third-degree burns: the role of a nanocrystalline silver dressing in facilitating resurfacing

Full-thickness burns of the face are notoriously difficult to repair and their management poses a series of problems to the surgeon. We present the case of a 49-year-old man (only survivor of a catastrophic airport accident) with third-degree flame burns to >80% of total body surface area and extensive face damage who achieved a fully satisfactory outcome after a treatment plan based on gradual escharectomy followed by application of artificial dermis and, later, grafting with sheets of cultured keratinocytes. Re-epithelialisation was already visible at day 16 after admission and all facial wounds were closed by day 56, the treatment continuing on the scalp. Within 6 months of the accident, the patient had recovered functional and cosmetic features (including re-growth of skin appendages) that were beyond expectations. The use of nanocrystalline silver-coated dressings during the escharectomy and resurfacing phases was important, as part of a multifaceted strategy, in ensuring excellent antimicrobial control, thus avoiding the need for autologous grafting and contributing to a rapid healing and complete restoration of the face and head skin.     

Phase II trial of alternating intravenous and oral vinorelbine in combination with cisplatin in advanced non-small cell lung cancer

Summary Cisplatin-based chemotherapy is the standard treatment for advanced non-small cell lung cancer (NSCLC). Several platinum-based doublets have been tested in phase II/III trials with equivalent results in terms of tumour response and survival. Our study was designed to evaluate activity, tolerability and convenience of alternating intravenous (i.v.) and oral vinorelbine in combination with cisplatin in advanced NSCLC. Forty chemo-naive patients with stage IV or relapsed unresectable disease and good performance status were enrolled to receive i.v. cisplatin 40 mg/m² on days 1 and 2 plus i.v. vinorelbine 25 mg/m² on day 1, every 3 weeks. Oral vinorelbine 60 mg/m² was given at home on day 5, without checking of blood cell count. A total of 175 treatment cycles were delivered. The overall response rate was 30% (one complete, 11 partial responses). Median time to progression and overall survival were 5 and 10 months, respectively. The main toxicity was haematological, with grade 3–4 neutropenia observed in 75% of patients, without febrile neutropenia. Non-haematological toxicity was mild. This schedule of cisplatin and vinorelbine treatment showed a good toxicity profile and an efficacy similar to other standard regimens. Oral vinorelbine could be administered safely at home on day 5.     

Lead exposure effect on angiotensin II renal vasoconstriction

Low levels of chronic lead exposure can produce hypertension and endothelial dysfunction, which could be associated with oxidative stress, changes in vascular tone and an imbalance of endothelial-derived vasoconstriction and vasodilator factors. The aim was to investigate the effect of chronic lead-exposure on angiotensin II-induced vasoconstriction in isolated perfused kidney and microvessels. Male Wistar rats (230-250 g) were treated for 12 weeks with lead acetate (100 ppm, Pbgroup) or pure water (control group). We evaluated the vascular reactivity in the kidneys and renal microvessels in the presence and absence of N(omega)-nitro-L-arginine methyl ester (L-NAME) in both groups. The nitrite concentration in renal perfusate was measured as an index of NO released, renal abundance of 3-nitrotyrosine was measured as well as endothelial NO synthase (eNOS) expression. Oxidative stress was measured by using the oxidative fluorescence dye dihydroethidium (DHE) to evaluate in situ production of superoxide and identified by confocal microscopy. Lead-exposure significantly increased blood pressure, eNOS protein expression, oxidative stress and vascular reactivity to angiotensin II. L-NAME potentiated vascular response to angiotensin II in control group but had no effect on the Pb-group. Nitrites released from the kidney of lead-group was lower compared to the control group while 3-nitrotyrosine was higher. This data suggest that lead-induced hypertension could be caused partially by an altered NOsystem.     

Efficacy and tolerability of a standardized herbal product from Galphimia glauca on generalized anxiety disorder. A randomized, double-blind clinical trial controlled with lorazepam

Galphimia glauca Cav. is a plant used in Mexican traditional medicine as a "nerve tranquilizer". Previous studies have demonstrated that the methanolic extract from this plant species possess an anxiolytic effect. Galphimine B (GB, a nor-seco-triterpene), is the active principle, with an innovative action mechanism. Against this background, a standardized herbal medicinal product was developed from the aqueous extract of G. glauca (GgHP). The present work compared the therapeutic effectiveness, safety, and tolerability of the new GgHP with lorazepam on patients with generalized anxiety disorder (GAD). By means of a controlled, randomized, double-blind clinical trial, outpatients of either sex who matched the DSM-IV diagnostic criteria with a score of > or = 19 points on the Hamilton Anxiety Scale (HAM-A) were included. The experimental group was treated orally with GgHP in capsules twice a day for 4 weeks. The control group received lorazepam (1 mg) under the same conditions and presentation. A total of 152 patients were included in the trial (72 in the experimental group). From the first week of treatment, GgHP showed important anxiolytic effectiveness, very similar to that produced with lorazepam. Both treatments showed therapeutic safety (no alterations on biochemical analysis of hepatic and renal function). Nevertheless, concerning side effects, GgHP evidenced a considerably higher tolerability than lorazepam.     

Mycological and electron microscopic study of Solanum chrysotrichum saponin SC-2 antifungal activity on Candida species of medical significance

Solanum chrysotrichum is utilized in traditional Mexican medicine for the treatment of mycotic skin infections. Several microbiological studies have provided evidence of its antifungal activity against dermatophytes and yeasts. S. chrysotrichum saponins have been identified as a group of compounds with antifungal activity and saponin SC-2 has demonstrated to be the most active. Previous clinical studies have shown the therapeutic effectiveness of S. chrysotrichum-derived saponin-standardized herbal products in the treatment of Tinea pedis and Pityriasis capitis. There is no previous evidence of the activity of these saponins against Candida non-albicans species, or fluconazole- and ketoconazole-resistant Candida strains. The present study reports the biological activity of the SC-2 saponin (inhibitory concentration [IC (50)] and minimum fungicide concentration [MFC]), against 12 Candida strains of clinical significance ( C. albicans, five strains; C. glabrata and C. parapsilosis, two; C. krusei, C. lusitaniae and C. tropicalis, one), including some fluconazole (Fluco)- and ketoconazole (Keto)-resistant clinical isolates. In addition, SC-2-associated microstructural alterations were reported in four of the above-mentioned Candida species. Seven strains had IC (50) of 200 microg/mL for SC-2, 400 microg/mL was found in four strains, and 800 microg/mL for a sole C. glabrata strain. Susceptibility to SC-2 saponin was as follows: C. albicans = C. lusitaniae > C. krusei > C. glabrata. The MFC was 800 microg/mL for the majority of strains (nine), 400 microg/mL for C. albicans (two strains) and C. lusitaniae. The ultrastructural Candida changes originated by SC-2 included the following: 1) damage on cytoplasmic membrane and organelles; 2) changes in cell wall morphology and density, with separation of cytoplasmatic membrane from cell wall and disintegration of the latter; and 3) total degradation of cellular components and death. Changes were manifested from 6 h of incubation, reaching their maximum effect at 48 h. In conclusion, the saponin SC-2 possesses fungicide and fungistatic activity on different Candida albicans and non- albicans species (including some azole-resistant strains) with IC (50) values of 200 microg/mL (in Fluco-susceptible strains) and of 400 - 800 mug/mL (in Fluco-resistant strains). Additionally, we observed by transmission electron microscopy (TEM) that saponin SC-2 causes severe changes in all fungal cell membranes, and to a lesser degree on the cell wall.