Evolution of gastropod mitochondrial genome arrangements

BACKGROUND

Gastropod mitochondrial genomes exhibit an unusually great variety of gene orders compared to other metazoan mitochondrial genome such as e.g those of vertebrates. Hence, gastropod mitochondrial genomes constitute a good model system to study patterns, rates, and mechanisms of mitochondrial genome rearrangement. However, this kind of evolutionary comparative analysis requires a robust phylogenetic framework of the group under study, which has been elusive so far for gastropods in spite of the efforts carried out during the last two decades. Here, we report the complete nucleotide sequence of five mitochondrial genomes of gastropods (Pyramidella dolabrata, Ascobulla fragilis, Siphonaria pectinata, Onchidella celtica, and Myosotella myosotis), and we analyze them together with another ten complete mitochondrial genomes of gastropods currently available in molecular databases in order to reconstruct the phylogenetic relationships among the main lineages of gastropods.

RESULTS

Comparative analyses with other mollusk mitochondrial genomes allowed us to describe molecular features and general trends in the evolution of mitochondrial genome organization in gastropods. Phylogenetic reconstruction with commonly used methods of phylogenetic inference (ME, MP, ML, BI) arrived at a single topology, which was used to reconstruct the evolution of mitochondrial gene rearrangements in the group.

CONCLUSION

Four main lineages were identified within gastropods: Caenogastropoda, Vetigastropoda, Patellogastropoda, and Heterobranchia. Caenogastropoda and Vetigastropoda are sister taxa, as well as, Patellogastropoda and Heterobranchia. This result rejects the validity of the derived clade Apogastropoda (Caenogastropoda + Heterobranchia). The position of Patellogastropoda remains unclear likely due to long-branch attraction biases. Within Heterobranchia, the most heterogeneous group of gastropods, neither Euthyneura (because of the inclusion of P. dolabrata) nor Pulmonata (polyphyletic) nor Opisthobranchia (because of the inclusion S. pectinata) were recovered as monophyletic groups. The gene order of the Vetigastropoda might represent the ancestral mitochondrial gene order for Gastropoda and we propose that at least three major rearrangements have taken place in the evolution of gastropods: one in the ancestor of Caenogastropoda, another in the ancestor of Patellogastropoda, and one more in the ancestor of Heterobranchia.

Docetaxel-induced interstitial pneumonitis following non-small-cell lung cancer treatment

Interstitial pneumonitis has been described infrequently following administration of docetaxel, used alone or in combination with other chemotherapeutic agents or concurrent irradiation, for non-small-cell lung cancer (NSCLC). This toxicity is of special relevance in NSCLC, as clinical severity and differential diagnosis may be especially challenging. It seems to be due to type I and type IV hypersensitivity reactions to the drug. Clinical and radiographic features are nonspecific and diagnosis is made by exclusion. The rate of grade III-IV docetaxel-induced pneumonitis, ranging from 7 to 47%, depends on several factors, including total dose, chemotherapy schedule and especially concomitant docetaxel treatment with gemcitabine and radiotherapy. Although the usual outcome is cure, it sometimes eventually progresses to pulmonary fibrosis despite steroid treatment. This toxicity must be taken into account when planning treatment strategies for NSCLC in order to reduce its rate and to achieve prompt diagnosis and treatment.

Biweekly paclitaxel as second-line treatment in advanced non-small cell lung-cancer (NSCLC). A phase II study of the Lung Cancer Galician Group

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Background: Paclitaxel is an active drug for NSCLC. Our purpose was to evaluate the efficacy and toxicity of biweekly administration of this drug in previously treated patients with advanced NSCLC. Methods: Patients with stage IIIB and IV NSCLC, which progressed after or during first-line chemotherapy, measurable disease, ECOG PS=0–1 and adequate organ function were included. Paclitaxel was administered at 150 mg/m2 iv, days 1 and 14, every 28 days, for a maximum of six cycles. Both, toxicity and efficacy analyses, were performed on the intent-to-treat (ITT) population. Results: Between September 2004 and November 2006, 42 patients (M/F, 39/3) were included, with median age 64 years (39–79). Tumor histology mainly included epidermoid (40.5%) and adenocarcinoma (35.7%). Tumor stage was IIIB (23.8%) and IV (76.2%). Median number of metastatic lesions was 1 (55%), located mainly in lymph nodes (30%), lung (25%), adrenal glands (16%) and bone (11%). Previous chemotherapy included platinum (76.1%), docetaxel (66.6%) and gemcitabine (52.4%). A total of 167 cycles (median 4, range 1–6) were administered. Median relative dose intensity was 94%. Toxicity: Grade III/IV hematologic toxicities per patient were neutropenia (2.5%) and anemia (2.5%). Grade III/IV non-hematologic toxicities were asthenia (2.5%), arthralgias/myalgias (2.5%) and peripheral neuropathy (2.5%). Efficacy: Of 39 ITT patients (3 patients have just begun chemotherapy), 7 achieved PR, 11 SD and 16 progressed, resulting in an ORR of 17.95% (95% CI: 5.9–30%). Five patients could not be evaluated for response due to early withdrawal (4 tumor-related exitus and 1 PS deterioration). Median TTP and OS were 174 days (95% CI: 115.52–232.48) and 332 days (95% CI: 261.18–402.82), respectively. Conclusions: Biweekly paclitaxel is an active and very well tolerated regimen in previously treated patients with advanced NSCLC.

No significant financial relationships to disclose.

A new HLA-B allele, HLA-B*4068, identified in an Equatorian individual

HLA-B*4068 shares exon 2 with HLA-B*4008 and exon 3 with HLA-B*4004.

Immunohistochemical profile of some neurotransmitters and neurotrophins in the seminiferous tubules of rats treated by lonidamine

Lonidamine (LND) or [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid] is an anticancer and antispermatogenic drug that exerts a large number of effects on tumor cells and germ cells. Sexually mature male Sprague-Dawley rats were housed at 22 degrees C on a 12-h light/12-h dark cycle 1 week before the experiments, with free access to food and water. LND was suspended in 0.5% methylcellulose at a concentration of 10 mg/mL and administered orally at the dose of 10 mL/kg (b.w.) as a single dose. Control rats received an equal amount of vehicle. Testes were removed, fixed for 24 h in 2% glutaraldehyde and 2% paraformaldehyde in 0.1 M sodium phosphate (pH 7.2 at 22 degrees C), rinsed with the same buffer, and stored at room temperature. From each sample, a block of tissue was removed by sectioning through the organ. After dehydration in ethanol at increasing concentrations (70-100%), each block was embedded in paraffin and serial 5 mm thick sections were cut using a rotatory microtome. The immunoreactivity for NTs has been observed in spermatogonia of untreated rats, while the rats treated with LND showed an immunohistochemical localization in all the stages of germinal cells. The generally well-expressed immunoreactivity for the neurotrophins receptors in treated rats observed in our study is presumably attributable to alterations of the receptors' structure and/or expression leading to changes of the activity, affinity, localization or protein interactions that may depend on sensitization of ion channels (induced by LND). Neurotrophins (NTs) appear to be interesting proteins for the modulation of sperm maturation and motility with a prominent role for the nerve growth factor (NGF), that may exert an autocrine or paracrine role. We therefore investigated the location and distribution of immunoreactivity for some neurotransmitters (SP, VIP, CGRP, nNOS, Chat), neurotrophins (NGF, BDNF, NT-3) and their own receptors (TrKA, TrKB, TrKC, p75) in the seminiferous tubules of male rats treated by LND in the light of the literature on this topic.

Growth hormone and insulin-like growth factor binding protein-1 responses to oral glucose in patients with primary hyperparathyroidism

BACKGROUND

GH and IGFBP-1 both play a role in glucose homeostasis.

OBJECTIVE

To assess the GH and IGFBP-1 responses to an oral glucose load and their relationship with glucose homeostasis in patients with primary hyperparathyroidism.

DESIGN

A cross-sectional study with a control group followed by a longitudinal study after parathyroidectomy.

PATIENTS AND METHODS

We studied 15 patients with primary hyperparathyroidism (eight women, aged 59.6 +/- 2.2 years) and nine healthy normocalcaemic controls. All subjects were ambulatory and were studied as outpatients. Glucose, insulin, GH and IGFBP-1 were measured during an oral glucose (75 g) tolerance test (OGTT).

RESULTS

Patients with hyperparathyroidism showed similar glucose responses to OGTT to those found in controls. Insulin responses were higher in patients (peak insulin 96.33 +/- 9.71 mU/l) in relation to values found in controls (58.11 +/- 9.03 mU/l; P < 0.01). Suppression of GH levels after OGTT was more marked in patients [nadir 0.03 (0.02-0.05) microg/l] than in normocalcaemic subjects [nadir GH 0.12 (0.08-0.42) microg/l; P = 0.002]. However, baseline IGFBP-1 concentration and its decrease after glucose load were similar in patients and controls. Normalization of calcium levels after parathyroidectomy was not followed by any significant changes in glucose, insulin and GH responses to OGTT. The minimum concentration of IGFBP-1 and the area under the curve (AUC) of IGFBP-1 after OGTT were higher after parathyroidectomy (3.34 +/- 0.69 microg/l and 8.94 +/- 1.72 microg x h/l, respectively) than at diagnosis (2.19 +/- 0.42 microg/l and 6.74 +/- 1.28 microg x h/l, respectively; P < 0.05). No correlation was found between PTH, calcium and phosphorus concentrations and GH and IGFBP-1 values in patients before or after normalization of calcium metabolism.

CONCLUSION

GH and IGFBP-1 do not seem to be directly involved in the hyperparathyroidism-associated changes in carbohydrate metabolism. The postoperative changes in the depression of IGFBP-1 after OGTT remain to be elucidated.

Multicenter phase II study of cetuximab and irinotecan as third line chemotherapy in patients (pts) with metastatic colorectal cancer (MCRC) previously treated with both irinotecan and oxaliplatin regimens

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Background: Pts with chemotherapy-resistant MCRC have a really poor prognosis with few therapeutic options. Cetuximab (Erbitux®) is an IgG1 monoclonal antibody targeting the EGFR, shown to be effective in pts with EGFR-expressing MCRC refractory to prior irinotecan-based chemotherapy (Cunningham NEJM 2004). Methods: The goal of this multicenter phase II study is to investigate the safety and efficacy of cetuximab in combination with irinotecan as third line treatment in 40 pts with heavily pre-treated MCRC. From Jan to Dec 2005, 40 pts with EGFR-expressing MCRC, refractory to irinotecan, pre-treated with both irinotecan and oxaliplatin with fluorouracil or capecitabine combinations, and PS 0–2, were included to receive cetuximab (400 mg/m2 week 1 and 250 mg/m2 weekly thereafter) plus irinotecan (180 mg/m2 every 2 weeks) until tumour progression or unacceptable toxicity. Pts were analysed weekly for toxicity and every 12 weeks for response. Recruitment is completed. Currently, 38 pts are evaluable for toxicity (2 pts recently recruited) and 23 pts for response (16 pts on treatment for <12 weeks and 1 pt withdrew at week 6 due to lung thromboembolism not related to study treatment). Results: M/F 24/14, median age 63 years (range: 33–78), colon/rectum 23/15, ECOG PS=0/1/2 9/23/6, Metastatic sites 1/2/>2 16/19/3 (Liver 43%, lung 23%, nodes 17%, pelvic 5%, others 12%). A total of 418 weekly infusions were administered (mean: 11; range: 3–37). Preliminary efficacy data is as follows: 3 PR, 3 SD, 17 PD with an overall response rate of 13% (95% CI: 3–34%) and disease control rate of 26% (95% CI: 10–48%). Major toxicities (G 1–2/G 3–4) were: Acne-like skin rash 58/11%, Anemia 32/3%, Neutropenia 16/13%, Nausea-vomiting 32/0%, Diarrhoea 32/11%. Median time to progression was 3.5 months (Range: 1–10+) and median overall survival was 7.3 months (Range: 1.5–12+). Conclusions: These preliminary results suggest that cetuximab and irinotecan combination, is a reasonably effective treatment for pts with highly pre-treated MCRC with an acceptable toxicity profile

No significant financial relationships to disclose.

The pathophysiology of hyperuricemia in essential hypertension: a pilot study

We have examined whether hyperuricemia in essential hypertension may be related to an increased insulin secretion thereby enhancing the tubular reabsorption of sodium and thus uric acid. Insulin hypersecretion, as elicited by the oral glucose tolerance test (OGTT), increased a mean of 5-fold in 12 essential hypertensive patients. Urinary uric acid to creatinine ratio significantly diminished by a mean of 62% after the OGTT. Simultaneously, urinary sodium to creatinine ratio decreased by a mean of 54%. These results suggest that insulin may mediate uric acid underexcretion due to its tubular sodium retaining effect in essential hypertensive patients.

Differential population structuring of two closely related fish species, the mackerel (Scomber scombrus) and the chub mackerel (Scomber japonicus), in the Mediterranean Sea

Population genetic structures of the mackerel (Scomber scombrus) and chub mackerel (Scomber japonicus) were studied in the Mediterranean Sea. Fragments of 272 bp (S. scomber) and 387 bp (S. japonicus) of the 5'-end of the mitochondrial control region were sequenced from spawning individuals collected off the coasts of Greece, Italy, Spain, and Portugal. High levels of mitochondrial control region haplotypic diversity (> 0.98) were found for both Scomber species. Nucleotide diversity was higher in the mackerel (0.022) than in the chub mackerel (0.017). Global F(ST) values were also higher and significant in the mackerel (0.024, P < 0.0001) as opposed to the chub mackerel (0.003, P > 0.05). Molecular variance analyses showed differential genetic structuring for these two closely related species. There is extensive gene flow between Mediterranean Sea and Atlantic Ocean populations of chub mackerel, which are organized into a larger panmictic unit. In contrast, Mediterranean Sea populations of mackerel show some degree of genetic differentiation and are structured along an east-west axis. The analysed eastern Mediterranean Sea mackerel populations (Greece, Italy) are clearly separated from that of the western Mediterranean Sea (Barcelona), which forms a panmictic unit with eastern Atlantic Ocean populations. The genetic structures of both species showed asymmetric migration patterns and indicated population expansion.

Phylogenetic relationships among Opisthobranchia (Mollusca: Gastropoda) based on mitochondrial cox 1, trnV, and rrnL genes

We reconstructed the phylogenetic relationships among 37 species representing seven main lineages within Opisthobranchia (Mollusca: Gastropoda) based on a mitochondrial fragment that included partial cox 1, complete trnV, and partial rrnL genes (about 2500 bp). Phylogenetic analyses confirmed tentatively that all studied main opisthobranch lineages conformed monophyletic groups except Nudibranchia. The sacoglossan Ascobulla was placed as the most basal lineage of opisthobranchs. The basommatophoran pulmonate Siphonaria was recovered within Opisthobranchia between Ascobulla and the remaining opisthobranchs. The latter were divided into two different lineages that await formal description: on one side, Cephalaspidea, Tylodinoidea, and Anaspidea (sharing features in the reproductive, digestive, and circulatory systems) were grouped together and, on the other Architectibranchia and Nudipleura (sharing similarities in the circulatory system) were recovered as sister group taxa. Two well-supported clades were recovered within Nudipleura: Pleuroanthobranchia (new taxon) and Cladobranchia. Pleuroanthobranchia (Pleurobranchoidea plus Anthobranchia) was defined by the presence of blood gland, the presence of calcareous spicules in the integument and the presence of a caecum with an opening directly into the stomach. The new molecular phylogeny provided a robust framework for comparative studies, and prompted a revision of the morphological synapomorphies diagnosing the main clades within opisthobranchs.

What is the relative contribution of blood glucose levels at different time points of the day to HbA1c in Type 1 diabetes?

AIMS

To evaluate the relative contribution of blood glucose levels at different time points of the day to HbA(1c) in Type 1 diabetes.

METHODS

Consecutive home blood glucose records (n = 146) from 71 Type 1 diabetic patients who were on an intensive diabetes therapy programme were examined. Each home blood glucose record included six daily blood glucose profiles over 2 months. The relationship between glycaemic values at each time point and HbA(1c) measured at the end of each record period was analysed.

RESULTS

Significant linear correlations were found between HbA(1c) and glycaemia at each time point of the day (ranged from 0.413 to 0.593), the strongest being with predinner glycaemia (r = 0.593; P = 0.000). Total daily glycaemia, mean preprandial and mean postprandial glycaemia were also significant and linearly correlated with HbA(1c) (r = 0.701; r = 0.686; r = 0.620, respectively; P < 0.0001). Multiple linear regression analysis showed that predinner, prebreakfast and post-breakfast glycaemia correlated significantly and independently with HbA(1c). The model accounted for 47.8% of the variance in HbA(1c).

CONCLUSIONS

Our study shows that among individual time points, prebreakfast and predinner are those with more influence on HbA(1c) in Type 1 diabetes and, to a lesser extent, post breakfast. It also confirms that preprandial glycaemia better predicts overall glycaemic control in Type 1 diabetes than postprandial glycaemia.

Chronic treatment with atypical neuroleptics induces striosomal FosB/DeltaFosB expression in rats

BACKGROUND

Studies have shown that neuroleptics regulate expression of the transcription factor FosB/DeltaFosB in the striatum, including the accumbens and caudate-putamen; however, the striatum is also divided into another structural dimension, the striosome and matrix compartments. The precise distribution of FosB/DeltaFosB induced by chronic neuroleptics in these striatal compartments is poorly understood.

METHODS

Rats received either single acute injections or chronic injections of clozapine (0 or 20 mg/kg, intraperitoneally [IP]), olanzapine (0 or 5 mg/kg, IP), or haloperidol (0 or 1.5 mg/kg, IP) for 25 days. The levels and compartmental distribution of FosB/DeltaFosB were examined.

RESULTS

Chronic clozapine induced clustered FosB/DeltaFosB expression within striosomes of the caudate-putamen. This pattern was due to increased levels of FosB/DeltaFosB in striosomes within the ventrolateral caudate-putamen and reduced levels of basal FosB/DeltaFosB in the matrix in the entire caudate-putamen. In contrast, chronic haloperidol increased FosB/DeltaFosB equally within the matrix and striosomes throughout the entire caudate-putamen. Chronic olanzapine induced an intermediate pattern.

CONCLUSIONS

The relative absence of FosB/DeltaFosB expression in the matrix correlates with the lack of parkinsonism of atypical neuroleptics. Expression of FosB/DeltaFosB in the matrix may contribute to parkinsonism of typical neuroleptics.