Tandem duplication of the NF1 gene detected by high-resolution FISH in the 17q11.2 region

The gene for neurofibromatosis type 1 (NF1), mapping to 17q11.2, has one of the highest observed mutation rates, partially because of its large size and gene conversion primed by NF1 pseudogenes. We have previously shown by means of high resolution fluorescence in situ hybridization (FISH) that a number of the loci flanking the NF1 gene are duplicated, in agreement with the reported presence of NF1 repetitive sequences (REPs). We report a direct tandem duplication of the NF1 gene identified in 17q11.2 by high-resolution FISH. FISH on stretched chromosomes with locus-specific probes revealed the duplication of the NF1 gene from the promoter to 3'UTR, but with at least the absence of exon 22. Fiber FISH with P1 artificial and bacterial artifical chromosomes, including the NF1 5'UTR and 3'UTR and flanking regions, visualized the direct tandem duplication with a similar, but not identical, genomic organization of the NF1 duplicon copies. Duplication was probably present in the human-chimpanzee-gorilla common ancestor, as demonstrated here by the finding of the duplicated NF1 gene at orthologous chromosome loci. The NF1 intrachromosomal duplication may contribute to the high whole-gene mutation rate by gene conversion, although the functional activity of the NF1 copy remains to be investigated. Detection of the NF1 duplicon by high-resolution FISH may pave the way to filling the gaps in the human genomic sequence of the pericentromeric 17q11.2 region.     

Allometric scaling of lung volume and its consequences for marine turtle diving performance

Marine turtle lungs have multiple functions including respiration, oxygen storage and buoyancy regulation, so lung size is an important indicator of dive performance. We determined maximum lung volumes (V(L)) for 30 individuals from three species (Caretta caretta n=13; Eretmochelys imbricata n=12; Natator depressus n=5) across a range of body masses (M(b)): 0.9 to 46 kg. V(L) was 114 ml kg(-1) and increased with M(b) with a scaling factor of 0.92. Based on these values for V(L) we demonstrated that diving capacities (assessed via aerobic dive limits) of marine turtles were potentially over-estimated when the V(L)-body mass effect was not considered (by 10 to 20% for 5 to 25 kg turtles and by >20% for turtles > or =25 kg). While aerobic dive limits scale with an exponent of 0.6, an analysis of average dive durations in free-ranging chelonian marine turtles revealed that dive duration increases with a mass exponent of 0.51, although there was considerable scatter around the regression line. While this highlights the need to determine more parameters that affect the duration-body mass relationship, our results provide a reference point for calculating oxygen storage capacities and air volumes available for buoyancy control.     

Excitation-contraction uncoupling during ischemia in the blood perfused dog heart

The bioluminescent of Ca(2+)-indicator, aequorin, was loaded into the left ventricular apex of blood-perfused hearts from 13 dogs for simultaneous recording of left ventricular pressure and intracellular calcium levels. During a 2 minute period of ischemia, systolic and diastolic pressures significantly decreased. In contrast, these pressure changes were associated with an increase in both systolic and diastolic calcium reaching a maximum diastolic value of 0.59 microM and a systolic value of 1.11 microM. This apparent dissociation between pressure and [Ca2+]i supports the hypothesis that changes in myofilament Ca2+ responsiveness are of major importance in modulating contractility during ischemia in large mammalian hearts.     

Conservation of peculiar structural properties by the hemoglobins of anguilloid eels (Teleostei)

The three species investigated, the European eel, Anguilla anguilla (L.), the Mediterranean moray, Muraena helena L., and the conger eel, Conger coner (L.), represent three different superfamilies of the suborder Anguilloidei (infradivision Elopomorpha). Their hemoglobin systems show peculiar structural properties, which distinuish them from all other teleost species studied. They present acidic and basic components differing greatly in their isoelectric points; the basic components have the highest isoelectric points detected in teleost hemoglobins. While there is one major basic component, multiplicity is present in the acidic components in Muraena and Conger. The polyeptides of the acidic comonents show the same electrophoretic mobility in 8 M urea. In the three species, the electroploretic mobility with urea-SDS of the hemoglobin polypeptides shows a shorter β polypeptide in the basic components. These features had never been investigated among Elopomorpha, and are likely to be phylogenetically relevant.     

Helminth communities of loggerhead turtles (Caretta caretta) from Central and Western Mediterranean Sea: The importance of host's ontogeny

We investigated the factors providing structure to the helminth communities of 182 loggerhead sea turtles, Caretta caretta, collected in 6 localities from Central and Western Mediterranean. Fifteen helminth taxa (10 digeneans, 4 nematodes and 1 acanthocephalan) were identified, of which 12 were specialist to marine turtles; very low numbers of immature individuals of 3 species typical from fish or cetaceans were also found. These observations confirm the hypothesis that phylogenetic factors restrict community composition to helminth species specific to marine turtles. There were significant community dissimilarities between turtles from different localities, the overall pattern being compatible with the hypothesis that parasite communities reflect the ontogenetic shift that juvenile loggerheads undergo from oceanic to neritic habitats. The smallest turtles at the putative oceanic, pelagic-feeding stage harboured only the 2 digenean species that were regionally the most frequent, i.e. Enodiotrema megachondrus and Calycodes anthos; the largest turtles at the putative neritic, bottom-feeding stage harboured 11 helminth taxa, including 3 nematode species that were rare or absent in turtles that fed partially on pelagic prey. Mean species richness per host was low (range: 1.60–1.89) and did not differ between localities. Variance ratio tests indicated independent colonization of each helminth species. Both features are expected in ectothermic and vagrant hosts living in the marine environment.     

Comparative Treatment of Helicobacter pylori–Positive Duodenal Ulcer Using Pantoprazole at Low and High Doses Versus Omeprazole in Triple Therapy

Background. Helicobacter pylori eradication has become the standard treatment for peptic ulcer disease. H. pylori –eradicating triple therapy with omeprazole plus two antibiotics has been used until recently; however, the efficacy of pantoprazole and antibiotics for H. pylori eradication has not been researched thoroughly until now. The aim of this randomized clinical trial was to verify the efficacy of triple oral therapy comparing the effects of pantoprazole using two different doses versus omeprazole twice daily in H. pylori eradication, in ulcer healing and relapses, and in gastritis improvement.
Materials and Methods. We enrolled 243 patients with H. pylori– positive duodenal ulcer and randomized them into three treatment groups: 84 patients (group Ome40) were assigned to receive omeprazole, 20 mg twice daily, plus amoxicillin, 1 gm twice daily, and clarithromycin, 500 mg twice daily for 10 days; 79 patients (group Pan40) were treated with pantoprazole, 40 mg daily, plus amoxicillin and clarithromycin at the same doses as those of group Ome40; and 80 patients (group Pan80) were treated with pantoprazole, 40 mg twice daily, plus amoxicillin and clarithromycin at the same doses as those of group Ome40.
Results. Ulcer healing was observed in 81 of 84 patients (96.4%) in group Ome40; in 66 of 79 patients (83.5%) in group Pan40; and in 77 of 80 patients (96.2%) in group Pan80. H. pylori was eradicated in 79 of 84 patients (94%) in group Ome40; in 63 of 79 patients (79.7%) in group Pan40; and in 75 of 80 patients (93.7%) in group Pan80.
Conclusions. We found that 10-day triple therapy with amoxicillin, clarithromycin, and either pantoprazole, 80 mg daily, or omeprazole, 40 mg daily, is highly effective in ulcer healing and is very well tolerated, achieving the 90% cure recommended for an ideal first-line anti– H. pylori positive duodenal ulcer treatment regimen.     

First records of dive durations for a hibernating sea turtle

The first published record, from the early 1970s, of hibernation in sea turtles is based on the reports of the indigenous Indians and fishermen from Mexico, who hunted dormant green turtles (Chelonia mydas) in the Gulf of California. However, there were no successful attempts to investigate the biology of this particular behaviour further. Hence, data such as the exact duration and energetic requirements of dormant winter submergences are lacking. We used new satellite relay data loggers to obtain the first records of up to 7h long dives of a loggerhead turtle (Caretta caretta) overwintering in Greek waters. These represent the longest dives ever reported for a diving marine vertebrate. There is strong evidence that the dives were aerobic, because the turtle surfaced only for short intervals and before the calculated oxygen stores were depleted. This evidence suggests that the common belief that sea turtles hibernate underwater, as some freshwater turtles do, is incorrect.     

Identification of a putative ribosomal protein mRNA in Chironomus riparius and its response to cadmium, heat shock, and actinomycin D

A putative ribosomal protein (rp) mRNA in Chironomus riparius has been found using differential display (DD). Its sequence has 84.8% identity with mosquito rp L8, Aedes albopictus, and is approximately 0.9 kb. Studies were undertaken in order to evaluate rp as a control for environmentally relevant genes. Responses of Drosophila heat shock 70 gene (hsp70) were used to establish heat shock temperatures and cadmium (Cd) concentrations for Chironomus experiments and to validate DD. Expression of hsp70 was induced over control by 28 degrees C at 30 minutes and 1 mM Cd at 24 hours (p< or =0.05). For Chironomus, DD, Northern blot, and nuclease sensitivity were used to measure responses to two stressors: heat shock for 30 minutes and Cd for 24 or 48 hours. Differential display and nuclease sensitivity assays found expression of rp mRNA at 37 degrees C and 16 mM Cd to be similar to controls. Northern blots indicated statistically significant effects for heat shock (p = 0.046) but not Cd (p = 0.406). However, mRNA levels at 37 degrees C were increased only 1.72-fold over controls. A concentration of 24 nM actinomycin D suppressed rp expression as measured by nuclease sensitivity assays. Stressors should not affect rp mRNA levels below their LC-50s.