It's not all black and white: investigating colour polymorphism in manta rays across Indo-Pacific populations.

Intraspecific colour polymorphisms have been the focus of numerous studies, yet processes affecting melanism in the marine environment remain poorly understood. Arguably, the most prominent example of melanism in marine species occurs in manta rays (Mobula birostris and Mobula alfredi). Here, we use long-term photo identification catalogues to document the frequency variation of melanism across Indo-Pacific manta ray populations and test for evidence of selection by predation acting on colour morph variants. We use mark-recapture modelling to compare survivorship of typical and melanistic colour morphs in three M. alfredi populations and assess the relationship between frequency variation and geographical distance. While there were large differences in melanism frequencies among populations of both species (0-40.70%), apparent survival estimates revealed no difference in survivorship between colour morphs. We found a significant association between phenotypic and geographical distance in M. birostris, but not in M. alfredi. Our results suggest that melanism is not under selection by predation in the tested M. alfredi populations, and that frequency differences across populations of both species are a consequence of neutral genetic processes. As genetic colour polymorphisms are often subjected to complex selection mechanisms, our findings only begin to elucidate the underlying evolutionary processes responsible for the maintenance and frequency variation of melanism in manta ray populations.

Effect of ursodeoxycholic acid on liver iron stores and distribution in rats with normal or iron-supplemented diet.

Iron excess is a potential liver-damaging factor, and bile salts can increase iron digestive absorption and iron biliary excretion. The aim of this study was to investigate in rats the effect of ursodeoxycholic acid, a bile salt used in the treatment of chronic liver disease, on the hepatic iron stores in normal and iron-overload conditions. UDCA was administered by gavage to Sprague-Dawley rats. Iron hyperabsorption and overload were obtained by 5% carbonyl iron addition in diet. Hepatic iron stores and distribution were evaluated by liver iron concentration measurement and histologic assessment, respectively. Whatever the iron content of the diet, liver iron concentration was not modified by UDCA administration compared with the control groups. Iron distribution was not modified by UDCA in rats with normal diet. The total iron score was only transiently lowered by UDCA in iron supplemented rats compared with the control group at 1 month. In conclusion, chronic UDCA administration does not modify liver iron stores and distribution in rats with both normal or increased digestive iron absorption. These data suggest that UDCA is unlikely to increase hepatic iron stores in treated patients and that the benefit of UDCA treatment is probably not related to a decreasing effect of liver iron content.

[Black esophagus. Three new cases]. / L'oesophage noir. Trois nouveaux cas.

We report three cases of "black esophagus" defined as a diffuse or patchy black color of the esophagus on endoscopy, associated with mucosa necrosis at histologic examination. Ischemia was invocated in two cases and alcaline reflux seemed to be likely in the third case. These observations are compared with the seven others cases previously reported in the literature.

[Endoscopic treatment and extracorporeal lithotripsy in chronic calcifying pancreatitis. Preliminary results in 16 patients]. / Traitement endoscopiquie et lithotritie extra-corporelle au cours de la pancréatite chronique calcifiante. Résultats préliminaires chez 16 patients.

UNLABELLED: A new therapeutic approach has been recently proposed in the management of chronic pancreatitis, including pancreatic endoscopic papillotomy and extracorporeal shock wave lithotripsy. The aim of this study was to assess the feasibility and the short--and long-term results of these procedures in a series of 16 patients aged 48.9 +/- 14 years. The indication for endoscopic treatment was pain in 15 cases and steatorrhea in one case. Pancreatic duct abnormalities included main pancreatic duct stenosis with calculi (9 cases), communicating pseudocysts upstream to a ductal stenosis or obstruction by calculi (4 cases), and isolated calculi (4 cases). Clinical response and morphologic parameters were used for analysis. Mean follow-up was 18.6 months (3.5 months to 7 years). RESULTS: a) pancreatic endoscopic papillotomy, stents placement, and extracorporeal shock wave lithotripsy were successfully performed in 15 out of 16 cases, 1 out of 4 cases and 8 out of 8 cases, respectively; b) symptomatic improvement was observed in 11 of 15 patients with painful pancreatitis as relief was complete in 8, and partial in 3 cases. Pain relapse occurred in these latter 3 patients 4, 18 and 48 months after treatment; diabetes mellitus remained unchanged in all cases; c) diameter of the main pancreatic duct and pancreatic calcifications decreased in 8 of 15 cases and in 10 of 15 cases, respectively; pseudocyst disappeared in 2 of 4 cases; clinical improvement was significantly correlated with pancreatic morphology improvement. Clinical relapse was associated with calculi recurrence in every case. No complication was observed. Endoscopic papillotomy and extracorporeal shock wave lithotripsy are feasible in most cases of chronic pancreatitis. Relief of pain is obtained rapidly after treatment and seems to be correlated with the quality of pancreatic drainage.

Magnetic resonance imaging and assessment of liver iron content in genetic hemochromatosis.

Computed tomography (CT) scanning is not highly sensitive in the assessment of liver iron content and magnetic resonance imaging (MRI) appears to be more efficient. The aim of this study was to determine the effectiveness of MRI in the evaluation of liver iron content using a standard spin-echo technique. The study included 23 patients with genetic hemochromatosis and 24 non-iron-overloaded patients as controls. A comparison was made of: (a) MRI signal intensity of liver, spleen, paravertebral muscles and subcutaneous adipose tissue using two different spin-echo sequences (SE 500/28; SE 2000/28,56); (b) liver attenuation determined by a single energy CT scan; and (c) a biochemical determination of hepatic iron. There was a significant decrease in liver signal intensity in the genetic hemochromatosis group (256 +/- 201, mean +/- S.D.) compared with the control group (801 +/- 413, p less than 0.001), but there was no correlation with liver iron concentration. However, such a correlation was found and was even more highly significant than in CT when the ratio between the liver and another organ was taken into account. For a lower limit of liver/spleen ratio calculated at 0.46 (mean 2 S.D. in the control group), the specificity (0.96) of MRI was satisfactory, but the sensitivity (0.78) remained insufficient (MRI being unable to detect an iron overload of up to 125 mumol/g). Hopefully, these results might be improved in the near future by using more sensitive sequences such as gradient echo sequences.

Unusual presentation of a case of brain abscess after endoscopic injection sclerotherapy of esophageal varices.

Although an increasing number and variety of complications of endoscopic injection sclerotherapy (EIS) of bleeding esophageal varices have been reported, infectious complications are rare. A case of brain abscess following EIS is reported which was characterised by an unusual clinical presentation in that there was no fever or leucocytosis. This presentation could have led to the abscesses being mistaken for brain metastases. The outcome of antimicrobial therapy was favorable which provided further evidence in support of the diagnosis.