Effects of dietary cholesterol on astaxanthin transport in plasma of Atlantic salmon (Salmo salar).

The effect of dietary cholesterol on astaxanthin (Ax) absorption and transport in the plasma of Atlantic salmon was investigated. Under controlled conditions, three experimental diets, non-pigmented diet (NPD), NPD with 40 mg Ax kg(-1), and NPD with 40 mg Ax kg(-1) and 2% cholesterol, were fed to juvenile salmon reared in sea water. After 12 weeks, blood was collected and plasma separated for analysis of plasma Ax and cholesterol content. In addition, plasma samples from each group of fish were fractionated into lipoproteins using a sucrose density gradient and ultracentrifugation. The apolipoprotein components of VLDL, LDL and HDL from each sample fraction were separated using SDS-PAGE. The addition of 2% cholesterol to the Ax-containing diet significantly increased the concentration of Ax and cholesterol in fish plasma. The protein-rich fraction was found to be the major carrier of Ax in salmon plasma. Cholesterol supplementation significantly increased Ax in plasma and VLDL as well as increasing plasma cholesterol. The VLDL fraction showed the most significant change in fish fed diet supplemented with cholesterol resulting in higher levels of Ax in this lipoprotein. The results clearly show that dietary cholesterol had a significant effect on the Ax transport process in the blood.

Effect of early introduction of microencapsulated diet to larval Atlantic halibut, Hippoglossus hippoglossus L. assessed by microarray analysis.

An experimental microdiet prepared using an internal gelation method was used to partially replace the traditional live feed (Artemia) for larval Atlantic halibut, Hippoglossus hippoglossus L. Three trials were conducted with microdiet introduced at 20, 32, and 43 days post first feeding and larvae were sampled at approximately 2, 13, 23, and 33 days after microdiet introduction in each trial. The success of feeding was assessed by morphometrics and histological analysis of gut contents. Microdiet particles were readily consumed after a period of adaptation and provided an adequate source of nutrients with no significant increase in mortality in the microdiet-fed group compared to the control group. However, growth was limited and there was an increased incidence of malpigmentation of the eye and skin. Subtle changes in underlying digestive and developmental physiology were revealed by microarray analysis of RNA from control and experimental fish given microdiet from day 20 post first feeding. Fifty-eight genes were differentially expressed over the four sampling times in the course of the trial and the 28 genes with annotated functions fell into five major categories: metabolism and biosynthesis, cell division and proliferation, protein trafficking, cell structure, and stress. Interestingly, several of these genes were involved in pigmentation and eye development, in agreement with the phenotypic abnormalities seen in the larvae.

Acute lead poisoning in an infant.

A case of acute lead poisoning in an infant without overt clinical manifestations of encephalopathy is reported for the first time in Oman. The case was diagnosed at Rustaq Hospital on the basis of (i) history by the mother of giving the child a traditional remedy for treating constipation (ii) X-ray of abdomen showing radio-opaque speckles and (iii) detection of high blood lead levels (83.3 µg/dL) at the toxicology laboratory of the poison control centre. The source of lead was confirmed by high content of inorganic lead (20.2%) found in the sample of the traditional remedy (bint al dahab). The blood lead levels significantly decreased, after the intravenous calcium edetate (EDTA) therapy was given to the baby. The case highlights that early detection and treatment of acute lead poisoning in children can prevent morbidity and sequelae associated with encephalopathy. It also indicated the need for awareness and prevention programme for parents on this issue.

Surgical treatment of atrial fibrillation with bipolar radiofrequency ablation: mid-term results in one hundred consecutive patients.

AIM: The Cox-Maze procedure was introduced nearly two decades ago for the surgical treatment of atrial fibrillation (AF). Recently, our group has replaced most of the incisions of the Cox-Maze procedure with bipolar radiofrequency (RF) ablations (Cox-Maze IV procedure). The purpose of this study was to examine our midterm results with the Cox-Maze procedure using bipolar RF ablation. METHODS: From January 2002 to October 2005, 100 consecutive patients underwent a modified Cox-Maze procedure with bipolar RF ablation for AF; 32 were lone operations, and 68 were concomitant procedures. Follow-up was performed at 1, 3, 6, and 12 months, and then annually thereafter. Heart rhythm was confirmed by electrocardiography. RESULTS: The mean age of patients was 62+/-13 years; 57% were male. Duration of AF was 6.3+/-7.6 years (0.1 to 40 years), 59% had paroxysmal AF, and 34% had permanent AF. Follow-up was complete for all patients with a mean follow-up of 13+/-10 months. At 12-month follow-up, 91% (49/54) of patients were free of AF. Cross-clamp time in the lone Cox-Maze IV procedure patients was 42+/-15 minutes, while it was 101+/-29 minutes for the Cox-Maze IV with a concomitant procedure (compared to 93+/-34 minutes and 122+/-37 minutes for the traditional procedure, P<0.05). There were four operative deaths. CONCLUSIONS: The Cox-Maze IV procedure had good mid-term efficacy. The use of bipolar RF energy significantly decreased operative time and simplified the procedure compared to the traditional Cox-Maze procedure, potentially increasing utilization of the procedure among cardiac surgeons.

Dietary fatty acid composition affects the repeat swimming performance of Atlantic salmon in seawater.

Repeated critical swimming performance trials (Ucrit) were performed on Atlantic salmon (Salmo salar) to test the null hypothesis that the source of dietary lipids (fish-based, poultry-based, and plant-based) does not influence exercise and recovery performance. Four diets were prepared by extensively replacing supplemental lipid from anchovy oil (AO; 100% AO at 150 g/kg) with cold pressed flaxseed oil (FO; 25% AO, 75% FO), sunflower oil (SO; 25% AO, 75% SO), or poultry fat (PF; 25% AO, 75% PF). These diets had equivalent protein and energy concentrations, but due to the different supplemental lipid sources, varied widely in their fatty acid composition. Fish fed AO had a significantly higher (P<0.05) first Ucrit (2.62+/-0.07 body lenght s(-1)) than those fed PF (2.22+/-0.12 body lenght s(-1)) that had low muscle ratios of n-3 highly unsaturated fatty acids (n-3 HUFA) to saturated fatty acids (SFA) and arachidonic acid (AA), and high levels of oleic acid. Fish in the FO and SO diet groups swam as well as AO-fed fish in both swimming trials. The performance of fish fed AO decreased significantly (P<0.05) during the second swimming trial (i.e. Ucrit2/Ucrit1=0.92+/-0.02). No significant differences occurred between diet groups for the second swim trial. There was a positive correlation between both n-3 HUFA/SFA and n-3 HUFA/AA ratios, and Ucrit1. A negative correlation was found between dietary AA and oleic acids, and Ucrit1. The present study suggests that low dietary n-3 HUFA/ SFA and n-3 HUFA/AA ratios may negatively affect swimming performance. The former possibly can be offset by increasing linoleic acid in the presence of nutritionally adequate n-3 HUFA (e.g. SO diet). Lipid supplements consisting largely of vegetable oils did not compromise fish cardiorespiratory physiology under the conditions of this study.

Profile of acute poisoning cases presenting to health centres and hospitals in Oman.

A simple pro forma was used for a retrospective study of poisoning cases at 45 health institutions in Oman during January-December 2000. No deaths were recorded among 2009 cases of acute poisoning. A quarter of all cases (55.8% of paediatric cases) were children aged 1-4 years. The largest category (59.5%) was animal bites and stings: 25.4% undiagnosed, 19.7% scorpion stings, 7.6% bee, spider or wasp stings and 6.8% snake bites. Next highest (38.5%) was ingestion of substances: 18.2% pharmaceuticals, 8.2% food and 4.7% household products. Most drug-related cases were due to paracetamol. Suicide attempts were recorded for 6.0%. Collection of poisoning data through a central registry system is needed for the implementation and future assessment of prevention programmes.

Profile of acute poisoning cases presenting to health centres and hospitals in Oman

A simple pro forma was used for a retrospective study of poisoning cases at 45 health institutions in Oman during January-December 2000. No deaths were recorded among 2009 cases of acute poisoning. A quarter of all cases [55.8% of paediatric cases] were children aged 1-4 years. The largest category [59.5%] was animal bites and stings: 25.4% undiagnosed, 19.7% scorpion stings, 7.6% bee, spider or wasp stings and 6.8% snake bites. Next highest [38.5%] was ingestion of substances: 18.2% pharmaceuticals, 8.2% food and 4.7% household products. Most drug-related cases were due to paracetamol. Suicide attempts were recorded for 6.0%. Collection of poisoning data through a central registry system is needed for the implementation and future assessment of prevention programmes

Cholinesterase inhibition by aluminium phosphide poisoning in rats and effects of atropine and pralidoxime chloride.

AIM: To investigate the cholinesterase inhibition and effect of atropine and pralidoxime (PAM) treatment on the survival time in the rat model of aluminium phosphide (AlP) poisoning. METHODS: The rats were treated with AlP (10 mg/kg; 5.55 x LD50; ig) and the survival time was noted. The effect of atropine (1 mg/kg, ip) and PAM (5 mg/kg, ip) was noted on the above. Atropine and PAM were administered 5 min after AlP. Plasma cholinesterase levels were measured spectrophotometrically in the control and AlP treated rats 30 min after administration. RESULTS: Treatment with atropine and PAM increased the survival time by 2.5 fold (1.4 h+/-0.3 h vs 3.4 h+/-2.5 h, P < 0.01) in 9 out of 15 animals and resulted in total survival of the 6 remaining animals. Plasma cholinesterase levels were inhibited by 47 %, (438+/-74) U/L in AlP treated rats as compared to control (840+/-90) U/L (P < 0.01). CONCLUSION: This preliminary study concludes that AlP poisoning causes cholinesterase inhibition and responds to treatment with atropine and PAM.

Effect of N-acetylcysteine and L-NAME on aluminium phosphide induced cardiovascular toxicity in rats.

AIM: To investigate the protective effects of N-acetylcysteine (NAC) and Nomega-Nitro-L-arginine methyl ester (L-NAME) on aluminium phosphide (AlP) poisoning induced hemodynamic changes, myocardial oxygen free radical injury and on survival time in rats. METHODS: AlP (12.5 mg/kg) was administered intragastrically under urethane anaesthesia. The effect of pre- and post-treatment with NAC and L-NAME alone and in combination was studied on haemodynamic parameters [blood pressure (BP), heart rate (HR), and electrocardiogram (ECG)] and biochemical parameters (malonyldialdehyde, catalase, and glutathione peroxidase). RESULTS: AlP caused significant hypotension, tachycardia, ECG abnormalities, and finally marked bradycardia. The mean survival time was (90 +/- 10) min. There was significant increase in myocardial malonyldialdehyde (MDA), and decrease in catalase and glutathione peroxidase (GSH Px) levels. NAC infusion (6.25 mg . kg-1 . min-1, iv for 30 min) caused insignificant hemodynamic and biochemical changes. Pre- and post-treatment of NAC with AlP significantly increased the survival time, stabilized BP, HR, and ECG, decreased MDA and increased GSH Px levels compared to AlP group. L-NAME infusion (1 mg . kg-1 . min-1, iv for 60 min) as such caused significant rise in BP but precipitated ECG abnormalities. Pre- and post-treatment of L-NAME with AlP neither improved the survival time nor the biochemical parameters despite significant rise in BP. Co-administration of both the drugs with AlP worsened the hemodynamic and biochemical parameters with reduction in the survival time as compared to AlP. CONCLUSION: NAC increased the survival time by reducing myocardial oxidative injury whereas L-NAME showed no such protective effects in rats exposed to AlP.

Conservation and divergence in molecular mechanisms of axis formation.

Genetic screens in Drosophila melanogaster have helped elucidate the process of axis formation during early embryogenesis. Axis formation in the D. melanogaster embryo involves the use of two fundamentally different mechanisms for generating morphogenetic activity: patterning the anteroposterior axis by diffusion of a transcription factor within the syncytial embryo and specification of the dorsoventral axis through a signal transduction cascade. Identification of Drosophila genes involved in axis formation provides a launch-pad for comparative studies that examine the evolution of axis specification in different insects. Additionally, there is similarity between axial patterning mechanisms elucidated genetically in Drosophila and those demonstrated for chordates such as Xenopus. In this review we examine the postfertilization mechanisms underlying axis specification in Drosophila. Comparative data are then used to ask whether aspects of axis formation might be derived or ancestral.

Grasshopper hunchback expression reveals conserved and novel aspects of axis formation and segmentation.

While the expression patterns of segment polarity genes such as engrailed have been shown to be similar in Drosophila melanogaster and Schistocerca americana (grasshopper), the expression patterns of pair-rule genes such as even-skipped are not conserved between these species. This might suggest that the factors upstream of pair-rule gene expression are not conserved across insect species. We find that, despite this, many aspects of the expression of the Drosophila gap gene hunchback are shared with its orthologs in the grasshoppers S. americana and L. migratoria. We have analyzed both mRNA and protein expression during development, and find that the grasshopper hunchback orthologs appear to have a conserved role in early axial patterning of the germ anlagen and in the specification of gnathal and thoracic primordia. In addition, distinct stepped expression levels of hunchback in the gnathal/thoracic domains suggest that grasshopper hunchback may act in a concentration-dependent fashion (as in Drosophila), although morphogenetic activity is not set up by diffusion to form a smooth gradient. Axial patterning functions appear to be performed entirely by zygotic hunchback, a fundamental difference from Drosophila in which maternal and zygotic hunchback play redundant roles. In grasshoppers, maternal hunchback activity is provided uniformly to the embryo as protein and, we suggest, serves a distinct role in distinguishing embryonic from extra-embryonic cells along the anteroposterior axis from the outset of development - a distinction made in Drosophila along the dorsoventral axis later in development. Later hunchback expression in the abdominal segments is conserved, as are patterns in the nervous system, and in both Drosophila and grasshopper, hunchback is expressed in a subset of extra-embryonic cells. Thus, while the expected domains of hunchback expression are conserved in Schistocerca, we have found surprising and fundamental differences in axial patterning, and have identified a previously unreported domain of expression in Drosophila that suggests conservation of a function in extra-embryonic patterning.

Effects of growth hormone and its secretagogues on bone.

The growth hormone (GH)/insulin-like growth factor-1 axis is not only of importance for linear body growth during childhood, but it is also one of the major determinants of adult bone mass. Studies show that GH treatment increases bone mass in rodents as well as in adult GH-deficient humans, but the effect of GH treatment on bone mass in healthy humans has so far not been impressive. Recently, a new class of GH secretagogues (GHSs) has been developed. In humans, GHS treatment affects biochemical markers of bone turnover and increases growth velocity in selected short children with or without GH deficiency. In rodents, GHS treatment increase bone mineral content, but it has not yet been shown that GHS treatment can affect bone mass in adult humans.

Growth hormone (GH)-independent stimulation of adiposity by GH secretagogues.

Growth hormone secretagogues (GHSs) stimulate growth hormone (GH) secretion, which is lipolytic. Here we compared the effects of twice daily s.c. treatment of GH and the GHS, ipamorelin, on body fat in GH-deficient (lit/lit) and in GH-intact (+/lit and +/+) mice. In +/lit and lit/lit mice ipamorelin induced a small (15%) increase in body weight by 2 weeks, that was not further augmented by 9 weeks. GH treatment markedly enhanced body weight in both groups. Ipamorelin also increased fat pad weights relative to body weight in both lit/lit and +/lit mice. Two weeks GHS treatment (ipamorelin or GHRP-6) also increased relative body fat, quantified by in vivo dual energy X-ray absorpiometry (DEXA) in GH-intact mice. GH decreased relative fat mass in lit/lit mice and had no effect in GH-intact mice. Treatment with GHS, but not GH, increased serum leptin and food intake in GH-intact mice. Thus, GHSs increase body fat by GH-independent mechanisms that may include increased feeding.

Serum insulin levels in non-obese, non-diabetic Asian Indians with acute coronary and non-coronary events.

Significant insulin resistance and hyperinsulinemia has been observed to be associated with coronary heart disease in epidemiological studies, particularly so in Asian Indians. This study attempted to investigate if hyperinsulinemia accompanies acute cardiovascular events in Asian Indians, and that it is not a metabolic response to acute stress alone. To test this hypothesis, a case-control study was carried out in a tertiary referral hospital in northern India. Group I (n = 19), consisting of non-diabetic, non-hypertensive, non-obese patients presenting with first episode of acute coronary event (first episode of angina or myocardial infarction) were compared with non-diabetic, non-hypertensive, non-obese patients of group II (n = 21) presenting with non-cardiovascular emergencies (severe abdominal pain e.g. uncomplicated ureteric colic or non-specific intestinal colic. Blood was analysed for glycosylated haemoglobin, fructosamine and insulin levels within 24 hours of the acute event. Elevated serum fructosamine was observed in 11 (57.8%) subjects in group I and 9 (42.9%) in group II (p = NS). Glycosylated haemoglobin was 6.8 +/- 0.1 percent in group I versus 5.9 +/- 0.04 percent in group II (p < 0.01). Three out of 11 subjects in group I and 1/9 subjects in group II having elevated serum fructosamine level also had increased glycosylated haemoglobin level. Five (26.3%) subjects in group I and 2 (9.5%) in group II with elevated glycosylated haemoglobin level were excluded from the analysis as these patients might have been diabetic. Mean serum insulin values were significantly higher in group I (161.3 +/- 8.15 micro IU/mL and 17.5 +/- 1.9 micro IU/mL in groups I and II, respectively; p < 0.001). Eleven (57.8%) subjects in group I had insulin values above 100 uIU/ml. The present study indicates that significant hyperinsulinemia accompanies acute cardiovascular events and it is not an acute response to pain or stress hyperglycemia. Markedly high insulin levels observed in these patients may have a potential role in the pathophysiology of acute coronary event, and may be further studied as a possible prognostic marker.

Effect of intra-tracheal instillation and inhalation of silicon dioxide on some biochemical variables in broncho-alveolar lavage fluid and lung histopathology in rats.

In the present study, the bronchial alveolar lavage fluid (BALF) biochemical and lung histopathological changes occurring in response to single large intra-tracheal exposure to silica have been compared to the changes seen after continued chronic exposure via inhalation. Male albino rats (200-250gms) were exposed to silicon dioxide via intratracheal instillation (8mg/0.05ml saline) and whole body inhalation (200mg/m3, 6 hours/day for 2 and 4 weeks) in separate groups . The respective control animals were instilled with normal saline (0.05ml) or exposed to fresh air in simulation chamber for the same duration. BALF was analyzed for total protein, elastase, malondialdehyde (MDA) levels and catalase activity and histopathology of right lung was carried out after 4 weeks post-exposure in intra-tracheal model and after 2 and 4 weeks of exposure in the inhalation model. The levels of total protein, elastase and malondialdehyde (MDA) were significantly elevated, while catalase activity was significantly decreased in the BALF of exposed animals as compared to controls. The histopathological studies of lungs, showed exudates of inflammatory cells, chiefly of macrophages in the alveolar spaces and interstitial septa with multifocal nodular granulomatous lesions. The biochemical findings in BALF of both the models indicate inflammatory changes, lipid peroxidation and fibrosis. However, comparatively lower catalase activity and higher elastase levels in the 4 week inhalationally exposed group than the 4 week post intratracheally exposed group, suggests that these parameters may be affected by acute and chronic exposure and require further confirmation.

The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats.

Growth hormone (GH) is of importance for normal bone remodelling. A recent clinical study demonstrated that MK-677, a member of a class of GH secretagogues (GHSs), increases serum concentrations of biochemical markers of bone formation and bone resorption. The aim of the present study was to investigate whether the GHSs, ipamorelin (IPA) and GH-releasing peptide-6 (GHRP-6), increase bone mineral content (BMC) in young adult female rats. Thirteen-week-old female Sprague-Dawley rats were given IPA (0.5 mg/kg per day; n=7), GHRP-6 (0.5 mg/kg per day; n=8), GH (3.5 mg/kg per day; n=7), or vehicle administered continuously s.c. via osmotic minipumps for 12 weeks. The animals were followed in vivo by dual X-ray absorptiometry (DXA) measurements every 4th week. After the animals were killed, femurs were analysed in vitro by mid-diaphyseal peripheral quantitative computed tomography (pQCT) scans. After this, excised femurs and vertebrae L6 were analysed by the use of Archimedes' principle and by determinations of ash weights. All treatments increased body weight and total tibial and vertebral BMC measured by DXA in vivo compared with vehicle-treated controls. However, total BMC corrected for the increase in body weight (total BMC:body weight ratio) was unaffected. Tibial area bone mineral density (BMD, BMC/area) was increased, but total and vertebral area BMDs were unchanged. The pQCT measurements in vitro revealed that the increase in the cortical BMC was due to an increased cross-sectional bone area, whereas the cortical volumetric BMD was unchanged. Femur and vertebra L6 volumes were increased but no effect was seen on the volumetric BMDs as measured by Archimedes' principle. Ash weight was increased by all treatments, but the mineral concentration was unchanged. We conclude that treatment of adult female rats with the GHSs ipamorelin and GHRP-6 increases BMC as measured by DXA in vivo. The results of in vitro measurements using pQCT and Archimedes' principle, in addition to ash weight determinations, show that the increases in cortical and total BMC were due to an increased growth of the bones with increased bone dimensions, whereas the volumetric BMD was unchanged.

Humoral and cell mediated immune response to cadmium in mice.

The effect of 30, 100 and 300 ppm of cadmium chloride (CdCl2) exposure for 35 days on humoral and cell mediated immune response was examined in Swiss Albino mice. Body burden of cadmium in kidney, spleen and liver was determined and histopathology of these organs was also done. Cadmium chloride in doses of 100 and 300 ppm when fed in drinking water caused significant decrease in IgM and IgG titre against sheep red blood cells (SRBC) and a significant decrease in IgG titre against bovine serum albumin (BSA). The delayed type hypersensitivity response to SRBC and splenic T cell proliferation to BSA was also significantly decreased following 100 amd 300 ppm cadmium exposure. Cadmium accumulation in the spleen, liver and kidney was associated with degeneration and inflammatory changes. It is concluded that cadmium causes significant suppression of humoral and cell mediated immune response in mice which could be due to its cytotoxic action on liver, kidney and immune cells.

Methemoglobinemia in aluminium phosphide poisoning in rats.

Aluminium phosphide (AlP) a grain fumigant is the leading cause of intentional poisoning in North India. The mechanisms involved in toxicity are not known and there is no antidote till date. The present study was carried out to investigate the oxygen free radical generation, methemoglobinemia and effect of methylene blue treatment on survival time in rat model of AlP poisoning. AlP (50 mg/kg, intragastric) was administered in one group and the other group received AlP + Methylene Blue (MB) (0.1%, 1 mg/kg/5 min, i.v.). Malonyldialdehyde (MDA) and methemoglobin (MeHb) levels were measured at 10 and 30 min intervals. Blood MDA levels increased at 10 and 30 min after AlP exposure with simultaneous rise in MeHb levels suggesting methemoglobinemia could be due to increased oxygen free radical generation. Methylene blue caused a significant fall in both the parameters with prolongation of survival time. It is concluded that AlP causes methemoglobinemia responding to methylene blue treatment.

Pulmonary histopathology and alteration in cellular pattern of bronchoalveolar lavage fluid in experimental silicosis.

Pathogenesis of silicosis is still being evaluated. Cellular and histopathological changes in lung following acute and chronic exposure of quartz in rats have been investigated. Inbred wistar rats were given single intratracheal injection of quartz (10 mg in 0.05 ml saline) in groups of acute model, and inhalation of quartz (40 mg/m3 with air flow 5 l/hr in a simulation chamber, 6 hr/day) in groups of chronic model. The control groups were exposed to vehicles only. Rats were sacrificed on day 3, 5 and 7 of intratracheal injection and after 2, 4 and 8 weeks of inhalation. Total and differential cell counts (TC and DC) were performed in bronchoalveolar lavage fluid (BALF). Histopathology was done in the lungs. There was significant (P < 0.001) increase in TC and significant (P < 0.001) changes in percentage of inflammatory cell counts on DC in the BALF of silicotic rats. Histopathology showed progressive inflammatory and fibrotic response in quartz exposed lungs in both acute and chronic models. The results indicate duration dependent inflammatory changes in lungs of both the models. Changes in cell counts precede the histopathological changes and may serve as early biological marker for detection of silicosis.