Occasional tillage in no-tillage systems: A global meta-analysis

No-tillage (NT) is a major component of conservation agricultural systems. Challenges that have arisen with the adoption of NT include soil compaction, weed management, and stratification of organic matter and nutrients. As an attempt to overcome these challenges, occasional tillage (OT) has been used as a soil management practice in NT systems. However, little is known about the impacts of OT on agronomic and environmental factors. For this reason, the objectives of this meta-analysis were: 1) to summarize the effects of OT on crop productivity, soil physical, chemical and biological properties, soil erosion and weed control; 2) to discuss the main aspects of NT management to optimize the use of OT; 3) to point out shortcomings in the diagnosis of soil compaction in NT systems, which may lead to erroneous decision-making processes regarding the use of OT. Overall, OT did not affect crops yields, although increased crop yields were observed in regions under water restriction and in soils with low retention capacity and water availability; OT improved soil physical properties (penetration resistance, soil bulk density, macroporosity, and total porosity), with persistence, generally, greater than 24 months, and decreased the soil aggregates stability; total organic carbon was reduced, particularly when plow/harrow was used and NT was already consolidated, and there was no effect on pH and available P; OT increased microbial biomass carbon, but had no effect on total microbial activity; soil erosion was reduced due to increased soil-water infiltration and reduced runoff, and finally, weed management was also improved by OT. It is suggested that suitable NT implementation and management, with the correct application of NT principles, will overcome problems associated with NT. As soil compaction is the main justification for the use of OT, methods of diagnosis and monitoring of soil compaction should be improved to assist in decision-making.

First report of Chalepus dorni (Coleoptera: Chrysomelidae: Cassidinae) in maize crops of Minas Gerais, Brazil

Se observaron larvas de dorni Chalepus en los cultivos de maíces comerciales en la región central de Minas Gerais durante los ciclos agrícolas 2006-2007, 2008-2009 y 2010-2011. El síntoma inicial se caracterizó por la presencia de minas en las hojas inferiores de plantas de maíz y la formación de áreas necróticas. Aunque existen informes de la presencia del género Chalepus en maíz, este sería el primer registro de C. dorni en maíz en Minas Gerais, Brasil.

Devastating complications after brachytherapy in the treatment of prostate adenocarcinoma

OBJECTIVE

To report a retrospective chart review of patients who developed recto-urethral fistula (RUF) or several bladder neck contracture (BNC) recurrences after brachytherapy for treating localized prostate cancer.

PATIENTS AND METHODS

In the past 3 years 18 patients with devastating complications after prostate brachytherapy were referred to our centre (RUF in 11, BNC in seven; mean age 63 years, range 60-81). All patients with RUF initially underwent diverting colostomy (six cystoprostatectomy with closure of the fistula, omental interposition and urinary diversion; one prostatectomy, bladder neck closure, fistula closure with omentum flap and continent vesicostomy). Three patients had the fistula closed with gracilis muscle flap using the York-Mason approach (one had a bladder neck closure and suprapubic tube; one elected to have no treatment). All patients with BNC had received three or more procedures to resect or incise their contracture. Four had diversion with a catheterizable segment, two used an indwelling Foley catheter and one uses intermittent catheterization.

RESULTS

All six patients who had cystoprostatectomy with urinary diversion have had no recurrence of their RUF. All three treated with the York-Mason procedure healed well. One developed recurrent prostate adenocarcinoma and two a secondary neoplasia in the prostate or rectum (leiomyosarcoma and neuroendocrine, respectively). The enterocystoplasty patient developed sepsis after colostomy reversal and subsequently died. In those patients with BNC, the four who underwent urinary diversion fared well; two tolerate the indwelling catheter poorly, and the seventh uses intermittent catheterization with occasional difficulty.

CONCLUSIONS

Brachytherapy with or without external irradiation can be associated with severe complications. RUF managed with aggressive anterior pelvic exenteration and urinary diversion can be associated with excellent results. The York-Mason procedure in patients with an adequate urinary continence mechanism and bladder dynamics may provide good functional results. The presence of a secondary malignancy in patients deserves further investigation. Many recurrences of a BNC tend be refractory to transurethral resection/incision; indwelling catheters are then poorly tolerated and patients may require a major reconstructive procedure.

Side-effect profile of sildenafil citrate (Viagra) in clinical practice

OBJECTIVES

Sildenafil citrate (Viagra) has been shown to be an effective treatment for erectile dysfunction. Initial studies reported a high tolerability and low incidence of certain characteristic adverse reactions. We sought to evaluate the incidence of side effects of sildenafil citrate, independent of industry support and constraints, utilizing a heterogeneous cohort of patients from a university-based practice.

METHODS

A prospective, open-label, flexible-dose study of 256 patients treated with sildenafil citrate for erectile dysfunction was performed at a single institution. The patients were questioned explicitly about the occurrence of headache, flushing, dyspepsia, nasal congestion, visual changes, and other side effects.

RESULTS

The adverse reactions most commonly observed were flushing (30.8%), headache (25. 4%), nasal congestion (18.7%), and heartburn (10.5%). All events were short lived and mild in nature. In the present study, 31.6% of patients experienced one or more adverse events. However, no one withdrew from the study because of the severity of these events. There was a significant association between higher doses and the occurrence of side effects.

CONCLUSIONS

The incidence of adverse events attributable to sildenafil citrate may be higher than initially reported, but an explanation may be the methodology of data collection and the industry-independent nature of this study. The side-effect profile is dose related and mild. Sildenafil citrate remains a safe and well-tolerated treatment for erectile dysfunction.