Dimorphism throughout the European eel's life cycle: are ontogenetic changes in head shape related to dietary differences?

A well-known link exists between an organism's ecology and morphology. In the European eel, a dimorphic head has been linked to differences in feeding ecology, with broad-headed eels consuming harder prey items than narrow-headed ones. Consequently, we hypothesized that broad-heads should exhibit a cranial musculoskeletal system that increases bite force and facilitates the consumption of harder prey. Using 3D-reconstructions and a bite model, we tested this hypothesis in two life stages: the sub-adult yellow eel stage and its predecessor, the elver eel stage. This allowed us to test whether broad- and narrow-headed phenotypes show similar trait differences in both life stages and whether the dimorphism becomes more pronounced during ontogeny. We show that broad-headed eels in both stages have larger jaw muscles and a taller coronoid, which are associated with higher bite forces. This increased bite force together with the elongated upper and lower jaws in broad-headed eels can also improve grip during spinning behavior, which is used to manipulate hard prey. Head shape variation in European eel is therefore associated with musculoskeletal variation that can be linked to feeding ecology. However, although differences in muscle volume become more pronounced during ontogeny, this was not the case for skeletal features.

Broader head, stronger bite: In vivo bite forces in European eel Anguilla anguilla.

This work examined three different phenotypes of the yellow-eel stage of the European eel Anguilla anguilla, broad-heads, narrow-heads and eels with an intermediate head shape. The aim was to see whether broad-headed A. anguilla, which generally consume harder, larger prey, such as crustaceans and fish, exerted greater bite force than the narrow-headed variant, which mainly consume soft, small prey such as chironomid larvae. It was found that in 99 yellow A. anguilla, in vivo bite force of broad-heads are higher compared with narrow-heads and intermediates.

[Physiological hydronephrosis in pregnancy: Occurrence and possible causes. An MRI study]. / L'hydronéphrose physiologique durant la grossesse : prévalences et causes possibles. Une étude basée sur l'IRM.

INTRODUCTION: The etiology of the uretero-hydronephrosis in pregnancy is just hypothesis: hormonal or mechanical hypothesis, only investigated by echographic studies. MRI permits to visualize the entirety of the urinary tract, which can be helpful to find out a mechanical cause. METHODOLOGY: We have analysed the MRI of 100 asymptomatic pregnant women. We have determined the number and locations of the uretero-hydronephroses and researched whether there is any relationship between the uretero-hydronephrosis and certain abdominal structures. We focused on the psoas muscle and measured its depth, width and calculated its surface by a reproducible method. RESULTS: The analysis revealed that the uretero-hydronephrosis was predominantly at the right side (63%) and in the majority of the cases limited to the kidney (42%) and/or the proximal third of the ureter (42%). We were able to rule out some proposed etiologies: a compression of the ureter between the uterus and the iliac or ovarian vessels; a protective effect of the left intestinal structures. A link was observed between the psoas muscle and the physiological uretero-hydronephrosis: the ipsilateral psoas muscle seemed smaller in pregnant women presenting a uretero-hydronephrosis. CONCLUSION: We have highlighted a link between a physiological uretero-hydronephrosis during pregnancy and a lesser developped psoas muscle. The hypothesis proposed is that a smaller psoas muscle would have a less protective effect of the ureter due to a lesser development. This study offers a practical conclusion: a left sided uretero-hydronephrosis during pregnancy and/or including the entirety of the ureter is more probably a pathological hydronephrosis. LEVEL OF EVIDENCE: 4.

Differential gene expression in narrow- and broad-headed European glass eels (Anguilla anguilla) points to a transcriptomic link of head shape dimorphism with growth rate and chemotaxis.

One of the major challenges in evolutionary biology is to understand the mechanisms underlying morphological dimorphism and plasticity, including the genomic basis of traits and links to ecology. At the yellow eel stage of the European eel (Anguilla anguilla), two morphotypes are found: broad- and narrow-heads. This dimorphism has been linked to dietary differences, with broad-heads feeding on harder, larger prey than narrow-heads. However, recent research showed that both morphotypes could be distinguished at the glass eel stage, the nonfeeding predecessor of the yellow eel stage, implying that nondietary factors play a role in the development of this head shape dimorphism. Here, we used transcriptome profiling (RNAseq) to identify differentially expressed genes between broad- and narrow-headed glass eels. We found 260 significantly differentially expressed genes between the morphotypes, of which most were related to defence and immune responses. Interestingly, two genes involved in growth (soma and igf2) were significantly upregulated in narrow-heads, while nine genes involved in chemotaxis showed significant differential expression. Thus, we found support for the observation that head shape is associated with somatic growth, with fast-growing eels developing a narrower head. Additionally, observations in the wild have shown that slow-growers prefer freshwater, while fast-growers prefer brackish water. The differential expression of genes involved in chemotaxis seems to indicate that glass eel growth rate and habitat choice are linked. We hypothesize that two levels of segregation could take place in the European eel: first according to habitat choice and second according to feeding preference.

Head shape dimorphism in European glass eels (Anguilla anguilla).

The life cycle of the European eel (Anguilla anguilla) remained a mystery until the 20th century, when Schmidt discovered that the Sargasso Sea was its spawning area. However, many aspects of the eel's life cycle remain poorly understood. Among these is the bimodal distribution in head shape, with broad- and narrowheaded phenotypes reported in the yellow eel stage. Although this has been linked to dietary preferences of the yellow eels, very little is known about why, how and when this dimorphism arises during their ontogeny. To determine whether this dimorphism indeed appears in relation to trophic niche segregation, we examined head shape variation at an earlier ontogenetic stage, the glass eel stage, as at this stage eels are considered to be non-feeding. Head shape was studied in a large dataset, containing glass eels captured from the Yser river mouth, the Leopold Canal (Belgium) and from the rivers Severn, Trent and Parret (UK), by both taking measurements (head width/head length) and using an outline analysis. Our results show that there is already considerable variation in broadness and bluntness of the head at the glass eel stage. In most cases, equal support for a unimodal and bimodal head shape distribution is found, whereas some cases support head shape bimodality in glass eels, suggesting that glass eel head shape might be shifting from a unimodal to a bimodal distribution. This, in combination with the observation that variation in head width/head length ratios in non-feeding glass eels shows a similar range as in feeding yellow eels, indicates that head shape in European eel might be at least partially determined through other mechanisms than trophic segregation.

Extramammary Paget's Disease : Case Report of a Penoscrotal Presentation.

We report the case of a 72 year old male with penoscrotal extramammary Paget's disease (EMPD). The patient presented with an eczematous lesion on the scrotum extending on to the base of the penis. Given the persistent and progressive nature of the lesion a biopsy was taken which revealed a malignant lesion suggestive of extramammary Paget's disease. After performing a CAT-scan of the lower abdomen and inguinal region, which was negative, a primary surgical approach with curative intentions was taken. One year after surgery the patient is doing well and shows no sign of local recurrence.

A comparison of the peri-operative data after open radical retropubic prostatectomy or robotic-assisted laparoscopic prostatectomy.

PURPOSES: To compare the peri-operative biochemical data, the postoperative need for help with hygiene and mobility, and the duration of bladder catheterization, hospitalization and ICU stay of patients undergoing radical retropubic prostatectomy (RRP) versus robotic-assisted laparoscopic prostatectomy (RALP) performed by an experienced open, yet inexperienced laparoscopic, surgical team, in a peripheral low-volume urological centre. METHODS: Over a 4-year period (2004-2008), 22 men underwent radical prostatectomy without lymphadenectomy at the study institution. The mean age of the patients was 63.9 years and the mean PSA value at the time of diagnosis was 9.2 ng/mL. RESULTS: Patients in the robotic-assisted laparoscopic prostatectomy group presented a significantly lower decrease in haemoglobin, haematocrit and total plasmatic protein and a significantly smaller need for help with hygiene and mobility and a shorter duration of bladder catheterization, hospitalization and ICU stay. CONCLUSIONS: The results of this study have shown that robotic-assisted laparoscopic prostatectomy is associated with lower peri-operative morbidity and a shorter hospital stay than radical retropubic prostatectomy, even when only considering the first performed robotic-assisted laparoscopic prostatectomies by a yet inexperienced robotic team in a peripheral low-volume urological centre.

Resistance of Four Inbred Maize Lines to Inoculation with 20 Isolates of Maize streak virus from Zimbabwe.

Maize streak is the most widespread and important disease of maize in sub-Saharan Africa. Maize streak virus (MSV)-resistant maize germ plasm is available in several countries, but little is known about the stability of its resistance to MSV strains that may differ from one region to another. We used four maize inbred lines (CML312, CML206, CML216, and MSR) known to differ widely for their resistance to MSV in Harare, and evaluated their resistance to 20 MSV isolates collected from the wild during 2 years at locations across Zimbabwe. Maize streak development and symptom severity were evaluated in replicated greenhouse experiments using artificial inoculation via viruliferous leafhoppers. All 20 MSV isolates induced maize streak symptoms on moderately and highly susceptible genotypes by about 1 week after inoculation (WAI). Differences among isolates for severity of early maize streak symptoms were ephemeral, and resistance was accurately differentiated by all isolates by 3 to 4 WAI. Differences in final maize streak symptom scores induced by the isolates were statistically significant, but differed only by a maximum of 7% in 1999 and 19% in 2000. Although genotype, isolate, and genotype by isolate effects for maize streak symptom scores were significant (P < 0.01), relative MSV resistance of the genotypes was consistently ranked by all 20 MSV isolates.

The correlation among cavernous pressure, penile rigidity and resistance index.

PURPOSE: We define the precise meaning and diagnostic significance of the resistance index generated by duplex scanning. MATERIALS AND METHODS: In 80 patients penile rigidity was clinically evaluated and a penile duplex scan was performed after intracavernous injection of 10 microg. prostaglandin E1. The intracavernous equilibrium pressure was measured in 34 of these patients. RESULTS: We found a statistically highly significant linear relationship among cavernous pressure, resistance index and penile rigidity (p <0.001). CONCLUSIONS: The resistance index and clinical degree of penile rigidity are 2 expressions of intracavernous pressure. Clinical observation of erection is equivalent to the resistance index in screening for cavernous leakage.

Gravity cavernosometry and assessment of complete smooth muscle relaxation: helpful in the differential diagnosis of cavernous leakage?

OBJECTIVE: To establish whether the relationship between cavernosal pressures and gravitational pressures of infused liquid during gravity cavernosometry is linear when complete smooth muscle relaxation is achieved and whether the determination of this relationship could be helpful in the differential diagnosis between organic and functional cavernous leakage. METHODS: Gravity cavernosometry was performed in 50 impotent patients. The cavernosal pressure was measured at at least four different gravitational pressures of the infused liquid. RESULTS: A linear relationship was obtained in all patients with normal maximal cavernosal pressure at gravity cavernosometry. A flat or nonlinear relationship was found in those with abnormal maximal pressure, whatever the cause of cavernous leakage. CONCLUSIONS: A linear relationship between cavernosal and gravitational pressures characterizes complete smooth muscle relaxation during gravity cavernosometry. However, the usefulness of the determination of this relationship is not yet established.

The effect of re-dosing of vasodilators on the intracavernosal pressure and on the penile rigidity.

PURPOSE: To study the effect of re-dosing of vasodilators on cavernous smooth muscle relaxation. METHODS: The intracavernosal pressure (ICP) was measured in 48 patients undergoing an intracavernosal injection test followed by gravity cavernosometry before and after administration of 1 or 2 booster injections with 20 micrograms prostaglandin E1 after an initial injection of a trimix of vasodilators. When submitted to Duplex scanning on another occasion, the injection of the trimix was followed by squeeze of the corpora. The occurrence of clinical full erection during the examinations was registered. RESULTS: The mean values of the ICP changed little, albeit statistically significant, after the first booster injection (+3.47 mm Hg) but not after the second one. With cavernosometry, a false diagnosis of cavernous leakage was made in at least 14 patients. During Duplex scanning, after the corpora were squeezed, 12 patients developed a clinical full erection, but none did during the intracavernosal injection test, even after re-dosing. A minimal drop in blood pressure was observed in 15 subjects after a booster injection. CONCLUSIONS: Administration of booster injections of 20 micrograms prostaglandin E1 after an initial injection of trimix did not induce sufficient cavernous smooth muscle relaxation. Squeezing of the corpora after injection of trimix was more successful.

The evaluation of arterial inflow by gravity cavernosometry.

PURPOSE: We determined whether the comparison between equilibrium pressure after intracavernous injection of vasodilators and maximal corporeal pressure at gravity cavernosometry could provide information about the relative contribution of arterial inflow and cavernous wall resistance to the erection process. MATERIALS AND METHODS: The results of gravity cavernosometry performed in 68 impotent patients were compared to those of duplex scanning in 53 and penile angiography in 10. RESULTS: A highly statistically significant (p < 0.01) but nonlinear correlation was observed between the equilibrium pressure after injection and maximal corporeal pressure, which indicates a paramount role of the corporeal veno-occlusive mechanism in the development of penile rigidity. However, in most patients with a pressure increase of more than 30 mm. Hg from the equilibrium pressure after injection to the maximal corporeal pressure, arterial insufficiency was diagnosed by duplex scanning and/or arteriography, and seemed to be the main limiting factor in the development of penile rigidity. CONCLUSIONS: Gravity cavernosometry provides functional information about the corporeal veno-occlusive mechanism and arterial inflow and, therefore, about the relative roles of these mechanisms in the development of penile rigidity.

The resistance index represents the corporeal pressure and not the cavernous wall resistance.

PURPOSE: We compare the results of the resistance index generated by duplex scanning and the corporeal pressure generated by the intracavernous injection test followed by gravity cavernosometry. MATERIALS AND METHODS: We examined 40 impotent subjects with duplex scanning and gravity cavernosometry. RESULTS: For the entire group a significant correlation (r = 0.77, p < 0.001) was found between the resistance index and intracavernous injection test, and between the resistance index and the gravity cavernosometry (r = 0.62, p < 0.01). Excluding the results of patients who had a full erection during scanning, the correlation between the resistance index and intracavernous injection test remained but the correlation between the resistance index and gravity cavernosometry disappeared (r = -0.02, p > 0.05). CONCLUSIONS: There was no relationship between the value of the resistance index and the cavernous wall resistance, except in patients capable of developing a full erection after vasodilator injection.

Influence of the method of intracavernous injection on penile rigidity: a possible pharmacokinetic explanation.

OBJECTIVES: To study whether the method of intracavernous injection of vasodilators has an effect on the clinical outcome and to explain the mechanism of possible influence. METHODS: In an open clinical study, penile rigidity after bolus injection was compared with rigidity after slow injection in 52 self-injecting, impotent patients. In 35 volunteers, venous plasma levels of intracavernosally injected drugs were followed under different injection conditions: slow injection of undiluted drug, slow injection of diluted drug, bolus injection, use of a tourniquet, or slow injection followed by squeeze of the corpora. RESULTS: Of the 52 patients, 28 reported better penile rigidity after a bolus injection than after slow injection of vasodilators. The other 24 reported no difference in rigidity. Systemic side effects did not occur, but 4 patients reported local pain after bolus injection. In the 35 volunteers, the lowest plasma levels were observed when a tourniquet was used or when a bolus injection was performed; the quickest transfer was observed after a slow injection of a low volume of the drug. CONCLUSIONS: Better rigidity was observed after bolus injection in a majority of the patients using the same dose of vasodilators. This could be due to the pharmacokinetic phenomenon of a slower drug transfer to the systemic circulatory system after a bolus than after a slow injection.

Pharmacodynamics of intracavernously injected drugs and cavernous wall resistance.

OBJECTIVE: It was our aim to investigate whether drug transfer from the cavernous bodies to the systemic circulation after intracavernous (i.c.) injection is influenced by the resistance of the cavernous wall. METHODS: i.c. injection of 62.5 micrograms digoxin as a tracer. (1) In 32 volunteers; in 5 together with the vasocontractor norepinephrine, in 20 together with a 'trimix' of vasodilators, in 7 alone without vasoactive drug. Plasma digoxin levels were measured after 5, 10 and 15 min. (2) Together with a trimix of vasodilators, in 30 men presenting a normal cavernosometry and in 30 men presenting an abnormal one. Plasma digoxin levels were measured after 2, 3, 5, 6, 10 and 15 min. RESULTS: (1) One minute after i.c. injection, the plasma peak of digoxin was 40 times higher (p < 0.01) after injection with norepinephrine than after injection with vasodilators. (2) There was a statistically significantly (p < 0.01) higher plasma digoxin level 5, 6, 10 and 15 min after injection in the 30 patients presenting an abnormal cavernosometry than in the 30 patients presenting a normal one. CONCLUSIONS: Drug transfer from the cavernous bodies to the systemic circulation is highly influenced by the resistance of the cavernous wall. It seems possible to diagnose cavernous leakage by means of a peripheral dosage of a routinely dosable drug, injected i.c. together with vasodilators.

Intracavernous injection of vasoactive drugs, an alternative for treating impotence in spinal cord injury patients.

We report on our results with the intracavernous injection and self-injection of papaverine-phentolamine in a group of spinal cord injury patients with erectile impotence. This technique offers the possibility of achieving a full erection which continues for a few hours and disappears afterwards. In our limited experience no major complications have occurred. If our findings are confirmed, in future, the self-injection technique may become a valuable alternative to implanting a prosthesis in impotent paraplegics and tetraplegics.

Intracavernous injection of noradrenaline to interrupt erections during surgical interventions.

Injection of a small dose of noradrenaline in one corpus cavernosum caused quick detumescence in 10 children and 7 adults with disturbing peroperative erections. The mode of administration is simple, and complications have not appeared. As this therapy has always been effective and avoids the need for deeper anesthesia, we dare to recommend it as first choice treatment for peroperative erections.