Structure and differential target sensitivity of the stimulable cytotoxic complex from hemolymph of the Mediterranean mussel Mytilus galloprovincialis

Radiation therapy has been for years the treatment of choice of locally advanced non small cell lung cancer. Improvement due to the combination of radiation and chemotherapy has been shown recently through several randomized trials and a recent meta-analysis. These results may be explained by biological mechanisms, yet uncompletely explored, which are detailed in this review and applied to lung cancer. The optimal combination scheme is not yet defined, even though the concurrent approach is promising, at the expense of an increased toxicity which is the limiting factor of treatment escalation doses. Biological findings and future results of randomized trials will hopefully open new avenues in the therapeutic strategy of this poor prognosis disease.     

Male-dependent doubly uniparental inheritance of mitochondrial DNA and female-dependent sex-ratio in the mussel Mytilus galloprovincialis

We have investigated sex ratio and mitochondrial DNA inheritance in pair-matings involving five female and five male individuals of the Mediterranean mussel Mytilus galloprovincialis. The percentage of male progeny varied widely among families and was found to be a characteristic of the female parent and independent of the male to which it was mated. Thus sex-ratio in Mytilus appears to be independent of the nuclear genotype of the sperm. With a few exceptions, doubly uniparental inheritance (DUI) of mtDNA was observed in all families fathered by four of the five males: female and male progeny contained the mother's mtDNA (the F genome), but males contained also the father's paternal mtDNA (the M genome). Two hermaphrodite individuals found among the progeny of these crosses contained the F mitochondrial genome in the female gonad and both the F and M genomes in the male gonad. All four families fathered by the fifth male showed the standard maternal inheritance (SMI) of animal mtDNA: both female and male progeny contained only the maternal mtDNA. These observations illustrate the intimate linkage between sex and mtDNA inheritance in species with DUI and suggest different major roles for each gender. We propose a model according to which development of a male gonad requires the presence in the early germ cells of an agent associated with sperm-derived mitochondria, these mitochondria are endowed with a paternally encoded replicative advantage through which they overcome their original minority in the fertilized egg and this advantage (and, therefore, the chance of an early entrance into the germ line) is countered by a maternally encoded egg factor.     

In vivo phosphorylation of phosphofructokinase from the bivalve mollusk Mytilus galloprovincialis

The objective of this study was to determine whether progesterone prevents the stimulatory effects of oestradiol on GnRH receptor gene expression. In Expt 1, ewes were treated during the luteal phase (days 10-12 of the oestrous cycle) with either one or five subcutaneous implants containing oestradiol (n = 6 per group). Control ewes received no treatment (n = 6). Anterior pituitary glands were collected 16 h after treatment with oestradiol. Steady-state amounts of GnRH receptor mRNA were similar among all three treatment groups despite increased circulating concentrations of oestradiol in implanted ewes at the time of pituitary collection (4.3 +/- 0.6 and 24.7 +/- 2.6 pg ml-1 in ewes treated with one or five implants, respectively, compared with 0.5 pg ml-1 in controls). Experiment 2 was designed to determine whether progesterone was the ovarian factor preventing the stimulatory effects of oestradiol on expression of the GnRH receptor gene in Expt 1. Twenty-five ewes were ovariectomized on day 6 or day 7 of the oestrous cycle and assigned to one of five treatment groups (n = 5 per group). Control ewes received no further treatment. Endogenous luteal phase concentrations of progesterone were replaced in three groups of ewes at the time of ovariectomy via intravaginal implants. Three days after ovariectomy, one group of progesterone-treated ewes received one oestradiol implant, while another group of progesterone-treated ewes received five oestradiol implants. An additional group was treated with five oestradiol implants only, and anterior pituitary glands were collected from all ewes 16 h later. Compared with untreated ovariectomized ewes, treatment with progesterone alone did not affect amounts of GnRH receptor mRNA. In ewes treated with progesterone and either one or five oestradiol implants, steady-state amounts of GnRH receptor mRNA were increased twofold (P < 0.01). Treatment with oestradiol in the absence of progesterone increased amounts of GnRH receptor mRNA threefold (P < 0.001). These results provide evidence that the stimulatory effects of oestradiol on the expression of the GnRH receptor gene are prevented during the natural luteal phase in ewes. However, progesterone does not appear to act independently to mediate this effect.     

Phosphofructokinase from mantle tissue of Mytilus galloprovincialis. Purification and effects of phosphorylation on the enzymatic activity

Phosphofructokinase purified from mantle tissue of the sea mussel Mytilus galloprovincialis, was phosphorylated "in vitro" by the catalytic subunit of cyclic AMP-dependent protein kinase. The incorporation of phosphate gave rise to an activation of the enzyme by increasing its affinity for fructose-6-phosphate, by decreasing its sensitivity to the inhibition by ATP and by enhancing the effect of allosteric activators (5'-AMP and fructose-2,6-bisphosphate). In addition, the effects of phosphorylation on the catalytic activity are pH-dependent.     

Migration and right atrial perforation of an Accufix atrial lead retention wire following partial lead removal during myomectomy

A 36-year-old man with a history of hypertrophic obstructive cardiomyopathy presented to the emergency room with "stabbing" chest pain. He had undergone dual-chamber pacemaker implantation in 1993 using an atrial lead (Accufix; Telectronics; Englewood, Colo) and a myomectomy in 1996 during which the distal portion of the atrial lead was removed. Digital fluoroscopy revealed that the retention wire had migrated out of the remaining atrial lead and perforated the right atrium. The retention wire was successfully removed percutaneously. The need for complete removal of the retention wire in the Accufix lead at the time of open-heart surgery is emphasized.     

Recognition of a 31,000 molecular weight protein synthesized by the mussel Mytilus galloprovincialis Lmk. during Dinophysis spp. algal bloom in the Gulf of Trieste (upper Adriatic Sea)

OBJECTIVES: To demonstrate gastroesophageal reflux induced by proximal gastrectomy and to report preventive measures, such as total gastrectomy followed by Roux-en-Y esophagojejunostomy. METHODS: Thirteen patients underwent proximal gastrectomy (PG), and six patients underwent total gastrectomy (TG). Two of the 13 patients who received PG later underwent completion total gastrectomy. All patients were followed with endoscopy, radionuclide scintigraphy, and 24-h pH monitoring. RESULTS: Endoscopic examination revealed evidence of esophagitis in all PG group patients; however, none of the TG group had esophagitis. Prolonged esophageal transit was observed in 11 patients (10 in the PG group, one in the TG group). Increased residual fraction was found in 10 patients (nine in the PG group, one in the TG group). An increase in the retrograde index was found in 14 cases (11 in the PG group, three in the TG group). Positive enterogastroesophageal reflux was identified in 11 patients (eight in the PG group, three in the TG group). Twenty-four hour pH monitoring resulted in 10 positives (10 in the PG group, none in the TG group). CONCLUSIONS: Frequently, proximal gastrectomy will lead to significant gastroesophageal reflux and, subsequently, to varying degrees of esophagitis. The clinical symptoms are usually characteristic. However, the severity of esophagitis and the mechanism of reflux can be determined only by integrated interpretation of a reflux study. The study should include endoscopy, radionuclide scintigraphy, and 24-h pH monitoring. Although a total gastrectomy with Roux-en-Y diversion can reduce the incidence of acid reflux, neutral enteroesophageal reflux may be observed during a radioactive isotope study. Fortunately, neutral refluxes rarely cause esophagitis. A proximal gastrectomy should be avoided in adenocarcinoma of the gastric cardia, except in early cancer. Symptomatic palliation can be relieved by medication. However, completion total gastrectomy is the only effective method for eradicating unrelenting symptoms.     

Rapid and simple determination of oxolinic acid and oxytetracycline in the shell of the blue mussel (Mytilus edulis) by high-performance liquid chromatography

A simple procedure for the determination of oxolinic acid (OA) and oxytetracycline (OTC), two antibacterial agents, in the shell of the blue mussel (Mytilus edulis), using reversed-phase high-performance liquid chromatography is described. Liquid chromatography was performed on a 5-microm LiChroSpher 100 RP-18E column using acetonitrile and a 0.02 M orthophosphoric acid solution as the mobile phase, with ultraviolet detection. After roughly grinding the shell, drugs were extracted using a methanolic oxalic acid solution. Linearity and precision were checked over the concentration range 0.04-0.32 microg/g. Limits of detection of OA and OTC were 0.012 and 0.008 microg/g, respectively. Mean extraction recoveries of OA and OTC from mussel shell were 72.9 and 65.4%, respectively. To demonstrate the usefulness of the analytical procedure, an experimental study was performed in blue mussels exposed to the drugs for eight days.     

Protrusion without fracture of the Accufix atrial "J" lead retention wire

The Telectronics Accufix atrial "J" lead has been associated with injury and death. These complications have occurred as the result of retention wire fracture, extrusion, and perforation of cardiac or vascular structures. This report describes a patient who was found to have protrusion of the proximal end of a nonfractured retention wire during fluoroscopic surveillance. The wire extrusion appeared to result from angulation of the lead. The lead was extracted and replaced without adverse consequences. Further prospective analysis will be needed to determine the clinical implications and approach to this complication.     

3H-Estradiol uptake and retention by target tissues of light-sterilized female rats

Tissue distribution of radioactivity was studied at 2, 4 and 6 h after intravenous injection of 3H-estradiol-17beta (41.7 ng/100 g b.w.) in 12 light-sterilized and 11 control female rats ovariectomized 72 h prior to injection. Female rats were light-sterilized by exposure to continuous illumination for 82 days and, based on the duration of continuous vaginal cornification and the absence of corpora lutea at post-mortem histological examination of the ovaries, were anovulatory for at least 30 days prior to injection. Control rats were housed under conditions similar to the experimentals except that they were exposed to alternating lighting (14 h light:10 h dark). They remained ovulatory throughout the experiment. Uterine 3H-estradiol uptake and retention were significantly depressed in the light-sterilized group. There were no significant differences in 3H-estradiol uptake or retention as a result of light-sterilization in any of the other tissues studied, including anterior, middle, and posterior hypothalamus, hippocampus, amygdala, cerebrum, anterior pituitary and plasma. The failure to detecta reduction in neural 3H-estradiol uptake demonstrates that the anovulatory state can exist without a concomitant reduction in the hypothalamic estrogen binding capacity. The possibility is discussed that the decreased target tissue binding noted in various types of anovulatory animals is the result, not the cause, of altered ovarian function.     

Species-specific segregation of gender-associated mitochondrial DNA types in an area where two mussel species (Mytilus edulis and M. trossulus) hybridize

In each of the mussel species Mytilus edulis and M. trossulus there exist two types of mtDNA, the F type transmitted through females and the M type transmitted through males. Because the two species produce fertile hybrids in nature, F and M types of one may introgress into the other. We present the results from a survey of a population in which extensive hybridization occurs between these two species. Among specimens classified as "pure" M. edulis or "pure" M. trossulus on the basis of allozyme analysis, we observed no animal that carried the F or the M mitotype of the other species. In most animals of mixed nuclear background, an individual's mtDNA came from the species that contributed the majority of the individual's nuclear genes. Most importantly, the two mtDNA types in post-F1 male hybrids were of the same species origin. We interpret this to mean that there are intrinsic barriers to the exchange of mtDNA between these two species. Because such barriers were not noted in other hybridizing species pairs (many being even less interfertile than M. edulis and M. trossulus), their presence in Mytilus could be another feature of the unusual mtDNA system in this genus.     

Reduction of vesicular acetylcholine transporter mRNA in the rat septum following lead exposure

We have previously observed that maternal exposure to lead (Pb) results in a reduction of levels of mRNA coding for cholineacetyltransferase (ChAT) in the septum of developing rat without affecting the dams. Here we report that Pb similarly affects the expression of vesicular acetylcholine transporter (VAChT) mRNA in the rat septum. In close agreement with the time course of ChAT mRNA expression, septal VAChT mRNA levels increased from 30% at postnatal day 7 to 78% and 100% of adult levels at days 14 and 21, respectively. Maternal exposure to 0.2% lead acetate in drinking water from gestational day 16 resulted in an approximately 30% reduction of VAChT in 7 and 21-day-old rat pups without affecting VAChT mRNA levels in the dams. These results indicate a developmental stage-dependent interference by Pb with ChAT/VAChT gene expression in the rat septum.     

Factors influencing uptake and retention of amino-containing drugs in large unilamellar vesicles exhibiting transmembrane pH gradients

The level of uptake and retention of amino-containing drugs in large unilamellar vesicles (LUVs) following uptake in response to a transmembrane pH gradient (DeltapH) can vary dramatically depending on the drug. For example, the anticancer drugs doxorubicin and epirubicin can be readily retained, whereas the anticancer drug vincristine and the antibiotic ciprofloxacin tend to leak out rapidly. In this investigation, we examine the influence of the hydrophobicity of the entrapped amines (that induce the DeltapH) and the anionic lipid content of the LUV on drug retention. It is shown that entrapment of increasingly hydrophobic monoamines (methylamine to amylamine) all lead to an induced DeltapH of 3 units and essentially complete drug uptake under the conditions employed, but do not lead to improved retention of vincristine and ciprofloxacin. However, significantly improved retention could be achieved by substitution of the anionic lipid distearoylphosphatidylglycerol (DSPG) for distearoylphosphatidylcholine (DSPC) in the LUV bilayer. Further, it is shown that if the induced DeltapH is reduced to 1.4 units (driven by entrapped diamine) nearly 100% accumulation of doxorubicin and epirubicin could be achieved, whereas only 25% loading for vincristine and ciprofloxacin was observed. Taken together these results provide methodology for improving (weak base) drug retention in liposomes and indicate that drugs that can partition into the lipid bilayer exhibit improved uptake and retention characteristics.     

Training effects on maternal and fetal glucose uptake following acute exercise in the rat

The purpose of the present study was to determine the effects of chronic maternal exercise on glucose uptake in maternal tissues after one bout of treadmill running during late gestation in the rat and to determine the effects on glucose accumulation in the fetus and placenta. Trained pregnant animals (PR) ran at 30 m.min-1, on a 10 degrees incline for 1 h on day 20 of gestation with a similarly treated trained nonpregnant group (NPR). Immediately after the run the animals were infused with a bolus of 1 g.kg-1 body wt as a 50% dextrose solution mixed with 2-deoxy-D-[1-3H] glucose through a carotid catheter. Sedentary pregnant (P) and nonpregnant animals (C) were also infused with the solution after no food and water for the same time frame. After 60 min, tissues were analyzed for radioactivity. Radioactive tracer was augmented in the red gastrocnemius and soleus of the PR group and the soleus of P rats. However, tracer accumulation in the fetus and placenta of the trained animals was not different than P animals. These results indicate that acute exercise in trained animals increased glucose uptake in maternal skeletal muscles without compromising conceptus glucose accumulation.     

Treatment of infection with débridement and retention of the components following hip arthroplasty

Forty-two patients (forty-two hips) who had an infection following a hip arthroplasty were managed with open débridement, retention of the prosthetic components, and antibiotic therapy. After a mean duration of follow-up of 6.3 years (range, 0.14 to twenty-two years), only six patients (14 per cent) -- four of nineteen who had had an early postoperative infection and two of four who had had an acute hematogenous infection -- had been managed successfully. Of the remaining thirty-six patients, three (7 per cent of the entire group) were being managed with chronic suppression with oral administration of antibiotics and thirty-three (79 per cent of the entire group) had had a failure of treatment. All nineteen patients who had a late chronic infection were deemed to have had a failure of treatment. Débridement had been performed at a mean of six days (range, two to fourteen days) after the onset of symptoms in the patients who had been managed successfully and at a mean of twenty-three days (range, three to ninety-three days) in those for whom treatment had failed. Débridement with retention of the prosthesis is a potentially successful treatment for early postoperative infection or acute hematogenous infection, provided that it is performed in the first two weeks after the onset of symptoms and that the prosthesis previously had been functioning well. In our experience, this procedure has not been successful when it has been performed more than two weeks after the onset of symptoms. Retention of the prosthesis should not be attempted in patients who have a chronic infection at the site of a hip arthroplasty as this approach universally fails.     

Defects in lead quenched from the liquid state

High purity (99.999 pct) lead samples are quenched from temperatures above as well as below the melting point and quenched-in defect properties are determined from electrical resistivity measurements. For quenching temperatures below the melting point, the vacancy formation energy, formation entropy and melting point concentration are found to be 0.63 ± 0.1 ev, 2.7 ± 0.5 eu, and 0.13 x 10^-3 mole fraction, respectively. The corresponding liquid quenching values are 0.35 ± 0.1 ev, 0.45 ± 0.2 eu, and 0.67 x 10^-3 mole fraction, respectively. These results indicate a discontinuity of 0.54 x 10^-3 mole fraction of vacancies at the melting point. Formerly Graduate Student, Department of Materials Science, California Institute of Technology     

PCBs in cod (Gadus morhua), flounder (Platichthys flesus), blue mussel (Mytilus edulis) and brown shrimp (Crangon crangon) from the Belgian continental shelf: relation to biological parameters and trend analysis

PCB levels in cod, flounder, mussel and shrimp, covering a ten-year period, were assessed for temporal trends and their relation to biological parameters. A significant relation was found between the PCB levels on a wet weight basis and the total lipid content. Normalising on the total lipid content reduced the differences in PCB levels between the organisms and between different tissues within the organisms. A general downward trend was observed for the PCB levels on the Belgian continental shelf.     

Clearance and tissue uptake following 4-hour and 24-hour infusions of pamidronate in rats

Bisphosphonates are clinically useful for the treatment of bone disorders; however, there is some controversy concerning the extent to which the design of the dosage regimen influences the efficacy of these drugs. The effect of different rates of infusion of [14C] pamidronate (APD; 3-amino-1-hydroxy-propylidene-1,1-bisphosphonate) (1 mg/kg infused over 4 or 24 hr) on its pharmacokinetics was investigated in rats by the measurement of tissue disposition and plasma clearance. The pharmacokinetic parameters, including total clearance, renal clearance, and nonrenal clearance, were found to be not significantly affected by the rate of infusion. The concentration of pamidronate in tibia, liver, kidney, and spleen was also unaffected by the two infusion rates. The bone (tibia) contained the highest concentration of all the tissues sampled, and the kidney accumulated the highest concentration among the soft tissues measured; this was in contrast to previous bolus administration studies where the liver and spleen contained higher concentrations than the kidney. The disposition kinetics of pamidronate were found to be essentially multiphasic, with a rapid initial half-life that gradually tails into a very long terminal phase. A terminal half-life could not be reliably estimated as it increased with time. As a consequence a model-independent approach, based on the calculation of the total, renal, and nonrenal clearance, best served to describe the disposition kinetics of pamidronate. For this unmetabolized compound the nonrenal clearance can be ascribed to tissue binding, which appears to be essentially irreversible.(ABSTRACT TRUNCATED AT 250 WORDS)