Les lésions de l’urètre associées à une fracture des corps caverneux. A propos d’une série de 4 cas et revue de la littérature

Introduction

Urethral injury associated with corpora cavernosa fracture is a relatively uncommon form of urological trauma. Early diagnosis and immediate surgical repair are essential.

Patients and methods

Between January 1990 and December 2004, a total of 4 male patients with urethral injury associated with fracture of the corpora cavernosa were retrospectively studied from a series of 96 cases of penile fracture.

Results

The mean age of the patients was 36.5 years (range: 27–45 years). Urethral bleeding was noted in all patients. Immediate surgical repair via a penile circular subcoronal incision was performed in all cases. Two partial urethral injuries associated with a unilateral corpus cavernosum lesion were identified. In the other cases, total urethral injury was associated with bilateral rupture of the corpora cavernosa. The tunica albuginea defect was closed and the urethral laceration repaired over a urethral catheter. With a mean follow-up of 2.5 years, 2 short urethral strictures were observed and were managed non-operatively with good outcome.

Comments

Secondary urethral lesions associated with corpora cavernosa fracture most frequently affect young adults. In North African countries, forced self-manipulation of an erect penis is the most frequent cause, but the associated urethral lesion is usually related to vaginal intercourse. The diagnosis can generally be made on the basis of history and physical examination alone. Blood at the meatus or haematuria or voiding difficulties suggest associated trauma to the urethra [4]. Additional imaging examinations are rarely required. The standard treatment is prompt surgical exploration, evacuation of haematoma, and primary repair of the urethral and corpora cavernosa defects. Late complications after surgical repair are penile curvature and pain during coitus. They are usually attributable to a residual fibrotic area.

Conclusion

Urethral injury associated with corpora cavernosa fracture usually has typical signs. The mechanism of trauma is very suggestive. Early surgical treatment is the only guarantee of a satisfactory functional result.     

Effects of grazing on plant species diversity and carbon partitioning in semiarid rangelands of northeastern China

Grasslands are one of the most widespread landscapes worldwide, covering approximately one-fifth of the world’s land surface, where grazing is a common practice. How carbon storage responds to grazing in steppes remains poorly understood. We quantified the effects of grazing on community composition and species diversity, and carbon storage in two typical grasslands of northeastern China, one in Horqin and the other one in Hulunbeier. In both grasslands, grazing did not influence plant species diversity. However, it substantially decreased aboveground carbon by 31% and 54% in Horqin and Hulunbeier, respectively. Fenced and grazing treatments showed a similar belowground carbon at both locations. The predominant carbon pool in the study grassland ecosystem was found in the upper 100 cm soil depth, from 98.2 to 99.1% of the total carbon storage. There were no significant effects of grazing on soil carbon neither in the whole profile nor in the uppermost 20 cm soil depth in the two study grasslands. Studies on the effects of varying rangeland management, such as region disparity and grazing systems, may have important consequences on species diversity and carbon partitioning, and thus on rangeland stability and ecosystem functioning.     

Application of magnetic techniques in the field of drug discovery and biomedicine

Magnetic separation technology, using magnetic particles, is quick and easy method for sensitive and reliable capture of specific proteins, genetic material and other biomolecules. The technique offers an advantage in terms of subjecting the analyte to very little mechanical stress compared to other methods. Secondly, these methods are non-laborious, cheap and often highly scalable. Moreover, techniques employing magnetism are more amenable to automation and miniaturization. Now that the human genome is sequenced and about 30,000 genes are annotated, the next step is to identify the function of these individual genes, carrying out genotyping studies for allelic variation and SNP analysis, ultimately leading to identification of novel drug targets. In this post-genomic era, technologies based on magnetic separation are becoming an integral part of todays biology laboratory. This article briefly reviews the selected applications of magnetic separation techniques in the field of biotechnology, biomedicine and drug discovery.     

Inverse folding of RNA pseudoknot structures

Background  

RNA exhibits a variety of structural configurations. Here we consider a structure to be tantamount to the noncrossing Watson-Crick and G-U-base pairings (secondary structure) and additional cross-serial base pairs. These interactions are called pseudoknots and are observed across the whole spectrum of RNA functionalities. In the context of studying natural RNA structures, searching for new ribozymes and designing artificial RNA, it is of interest to find RNA sequences folding into a specific structure and to analyze their induced neutral networks. Since the established inverse folding algorithms, RNAinverse, RNA-SSD as well as INFO-RNA are limited to RNA secondary structures, we present in this paper the inverse folding algorithm Inv which can deal with 3-noncrossing, canonical pseudoknot structures.     

Patch-clamp recording of charge movement, Ca(2+) current, and Ca(2+) transients in adult skeletal muscle fibers

Intramembrane charge movement (Q), Ca(2+) conductance (G(m)) through the dihydropyridine-sensitive L-type Ca(2+) channel (DHPR) and intracellular Ca(2+) fluorescence (F) have been recorded simultaneously in flexor digitorum brevis muscle fibers of adult mice, using the whole-cell configuration of the patch-clamp technique. The voltage distribution of Q was fitted to a Boltzmann equation; the Q(max), V(1/2Q), and effective valence (z(Q)) values were 41 +/- 3.1 nC/&mgr;F, -17.6 +/- 0.7 mV, and 2.0 +/- 0.12, respectively. V(1/2G) and z(G) values were -0.3 +/- 0.06 mV and 5.6 +/- 0.34, respectively. Peak Ca(2+) transients did not change significantly after 30 min of recording. F was fit to a Boltzmann equation, and the values for V(F1/2) and z(F) were 6.2 +/- 0.04 mV and 2.4, respectively. F was adequately fit to the fourth power of Q. These results demonstrate that the patch-clamp technique is appropriate for recording Q, G(m), and intracellular [Ca(2+)] simultaneously in mature skeletal muscle fibers and that the voltage distribution of the changes in intracellular Ca(2+) can be predicted by a Hodgkin-Huxley model.     

Finding our way around the sensory-motor corner

Our understanding of how sensory information is transformed into motor commands has grown increasingly sophisticated. In this issue of Neuron, Wilmer and Nakayama use a novel analysis to show that the initial changes in smooth-pursuit eye speed are driven by low-level motion signals, whereas the later eye speed is determined by high-level signals.