First Report of a Group 16SrII Phytoplasma Associated with Witches'-Broom of Eggplant in Oman.

Eggplant (Solanum melongena L.) belongs to the family Solanaceae and is an important vegetable cash crop grown in most parts of Oman. In February 2010, plants showing phyllody symptoms and proliferation of shoots resembling those caused by phytoplasma infection were observed at Khasab, 500 km north of Muscat. Total genomic DNA was extracted from healthy and two symptomatic plants with a modified (CTAB) buffer method (2) and analyzed by direct and nested PCR with universal phytoplasma 16S rDNA primers P1/P7 and R16F2n/ R16R2, respectively. PCR amplifications from all infected plants yielded an expected product of 1.8 kb with P1/P7 primers and a 1.2-kb fragment with nested PCR, while no products were evident with DNA from healthy plants. Restriction fragment length polymorphism (RFLP) profiles of the 1.2-kb nested PCR products of two eggplant phyllody phytoplasma and five phytoplasma control strains belonging to different groups used as positive control were generated with the restriction endonucleases RsaI, AluI, Tru9I, T-HB8I, and HpaII. The eggplant phytoplasma DNA yielded patterns similar to alfalfa witches'-broom phytoplasma (GenBank Accession No. AF438413) belonging to subgroup 16SrII-D, which has been recorded in Oman (1). The DNA sequence of the 1.8-kb direct PCR product was deposited in GenBank (Accession No. HQ423156). Sequence homology results using BLAST revealed that the eggplant phyllody phytoplasma shared >99% sequence identity with Scaevola witches'-broom phytoplasma (Accession No. AB257291.1), eggplant phyllody phytoplasma (Accession No. FN257482.1), and alfalfa witches'-broom phytoplasma (Accession No. AY169323). The RFLP and BLAST results of 16S rRNA gene sequences confirm that eggplant phyllody phytoplasma is similar to the alfalfa phytoplasma belonging to subgroup 16SrII-D. To our knowledge, this is the first report of a phytoplasma of the 16SrII-D group causing witches'-broom disease on eggplant in Oman. References: (1) A. J. Khan et al. Phytopathology 92:1038, 2002. (2) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA, 81:8014, 1984.

First Report of a Group 16SrII Phytoplasma Infecting Chickpea in Oman.

Chickpea (Cicer arietinum), locally known as "Dungo", is grown for legume and animal feed mainly in the interior region of Oman. During February 2006, survey samples of chickpea leaves from plants showing yellows disease symptoms that included phyllody and little leaf were collected from the Nizwa Region (175 km south of Muscat). Total nucleic acid was extracted from asymptomatic and symptomatic chickpea leaves using a cetyltrimethylammoniumbromide method with modifications (3). All leaf samples from eight symptomatic plants consistently tested positive using a polymerase chain reaction assay (PCR) with phytoplasma universal primers (P1/P7) that amplify a 1.8-kb phytoplasma rDNA product and followed by nested PCR with R16F2n/R16R2 primers yielding a product of 1.2 kb (2). No PCR products were evident when DNA extracted from healthy plants was used as template. Restriction fragment length polymorphism analysis of nested PCR products by separate digestion with Tru9I, HaeIII, HpaII, AluI, TaqI, HhaI, and RsaI restriction enzymes revealed that a phytoplasma belonging to group 16SrII peanut witches'-broom group (2) was associated with chickpea phyllody and little leaf disease in Oman. Restriction profiles of chickpea phytoplasma were identical with those of alfalfa witches'-broom phytoplasma, a known subgroup 16SrII-B strain (3). To our knowledge, this is the first report of phytoplasma infecting chickpea crops in Oman. References: (1) A. J. Khan et al. Phytopathology, 92:1038, 2002. (2). I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998 (3) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA. 81:8014, 1984.

First Report of 16S rDNA II Group Phytoplasma on Polygala mascatense, a Weed in Oman.

Polygala mascatense Boiss. (family Polygalaceae) is a common weed found in neglected farms, under date palm trees, and in stony locations throughout the Sultanate of Oman (1). It is a perennial herb approximately 30 to 40 cm tall, has slender branches, is woody at the base, and has linear leaves with purple flowers. Recently (November 2004), in the interior region of Oman (210 km south of Muscat), some polygala plants were found stunted with small leaves, bushy growth, and the floral parts were showing phyllody symptoms. Total genomic DNA extracted from asymptomatic and symptomatic plants with modified cetyltrimethylammoniumbromide (CTAB) buffer method (4) was used as a template for direct polymerase chain reaction (PCR) amplification of phytoplasma 16S rDNA with P1/P7 primers. Direct PCR product was used as template DNA for nested PCR with primers R16F2n/R16R2. DNA from plants infected with alfalfa and lime witches'-broom phytoplasma was used as positive controls, and DNA from healthy plants and water was used as negative controls. Products from nested PCR (1.2 kb) were analyzed by using single endonuclease enzyme digestion (restriction fragment length polymorphism [RFLP]) with Tru9I, HaeIII, HhaI, TaqI, AluI, and RsaI (3). The results showed the presence of a 1.8-kb product amplified with direct PCR and a 1.2-kb product of the nested PCR from infected polygala and the positive controls, whereas no PCR products were observed in the negative controls. The PCR assay confirmed the presence of phytoplasma causing witches'-broom disease in polygala. The RFLP results showed the polygala phyto-plasma to be most similar to the alfalfa phytoplasma, a member of 16SrII group (2). Infected polygala weeds may serve as a reservoir for alfalfa witches'-broom phytoplasma that causes annual losses over $25 million to alfalfa cultivation in Oman (2). A detailed investigation needs to be carried out to establish transmission of phytoplasma from polygala to alfalfa. To our knowledge, this is the first report of phytoplasma infecting polygala weeds in Oman. References: (1) S. A. Ghazanfar. Pages 95-96 in: An Annotated Catalogue of the Vascular Plants in Oman. Scripta Botanica Belgica Meise, National Botanic Garden of Belgium, 1992. (2) A. J. Khan et al. Phytopathology 92:1038, 2002. (3) I. M. Lee et al. Int. J. Syst. Bacteriol. 1153, 1998. (4) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA 81:8014, 1984.

The use of ezetimibe in achieving low density lipoprotein lowering goals in clinical practice: position statement of a United Kingdom consensus panel.

There is no doubt that lowering serum cholesterol levels reduces the risk of major coronary events. This evidence has led treatment guidelines to set progressively lower targets for low density lipoprotein cholesterol (LDL-C). However, despite widespread use of statins, substantial numbers of patients do not achieve the LDL-C goals. Using higher doses of statins in an attempt to achieve these targets may increase the risk of serious adverse effects. Furthermore, the use of combination therapy with agents such as bile acid sequestrants, niacin and fibrates has been limited by increased potential for side effects, drug interactions and poor compliance. Ezetimibe, a selective cholesterol transport inhibitor, reduces the intestinal uptake of cholesterol without affecting absorption of triglycerides or fat-soluble vitamins. In clinical studies, ezetimibe 10 mg, in combination with statins or as monotherapy, was well tolerated and reduced LDL-C by 34-53% and 17-18%, respectively. The available evidence for ezetimibe is reviewed. The role of ezetimibe in increasing the proportion of patients attaining LDL-C treatment goals is discussed.

First Report of Witches'-Broom Disease of Sesame (Sesamum indicum) in Oman.

Sesame is the major oil seed crop in Oman. During 2004, disease symptoms were observed at Nizwa, 175 km south of Muscat. Symptoms included phyllody and excessive development of short shoots and internodes resulting in little leaves. Total genomic DNA was extracted from healthy and symptomatic plants with a modified cetyltrimethylammoniumbromide (CTAB) buffer method (2). DNA samples were assayed by polymerase chain reaction (PCR), with the 16S rDNA amplified using primers P1 and P7. Direct PCR products were used as template DNA for nested PCR with primers R16F2n and R16R2. Direct PCR products were analyzed by restriction fragment length polymorphism (RFLP) with four restriction enzymes, Tru9I, HaeIII, HhaI, and RsaI. DNAs from alfalfa and lime plants infected by witches'-broom phytoplasmas were used as positive controls and DNA from healthy plants and water were negative controls. The results showed the presence of a 1.8-kb product amplified with the direct PCR and a 1.2-kb product of the nested PCR from infected sesame and the positive controls. No PCR product was observed in the negative control. The PCR assay confirmed the presence of phytoplasma causing witches'-broom disease in sesame. The RFLP results showed the sesame phytoplasma to be most similar to the alfalfa phytoplasma, a member of 16SrII group (1). To our knowledge, this is the first report of a phytoplasma of the 16Sr II group causing witches'-broom disease on sesame in the Sultanate of Oman. References: (1) A. J. Khan et al. Phytopathology 92:1038, 2002. (2) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA, 81:8014, 1984.

Left atrial appendage: structure, function, and role in thromboembolism.

The left atrial appendage (LAA) is derived from the left wall of the primary atrium, which forms during the fourth week of embryonic development. It has developmental, ultrastructural, and physiological characteristics distinct from the left atrium proper. The LAA lies within the confines of the pericardium in close relation to the free wall of the left ventricle and thus its emptying and filling may be significantly affected by left ventricular function. The physiological properties and anatomical relations of the LAA render it ideally suited to function as a decompression chamber during left ventricular systole and during other periods when left atrial pressure is high. These properties include the position of the LAA high in the body of the left atrium; the increased distensibility of the LAA compared with the left atrium proper; the high concentration of atrial natriuretic factor (ANF) granules contained within the LAA; and the neuronal configuration of the LAA. Thrombus has a predilection to form in the LAA in patients with atrial fibrillation, mitral valve disease, and other conditions. The pathogenesis has not been fully elucidated; however, relative stasis which occurs in the appendage owing to its shape and the trabeculations within it is thought to play a major role. Obliteration or amputation of the LAA may help to reduce the risk of thromboembolism, but this may result in undesirable physiological sequelae such as reduced atrial compliance and a reduced capacity for ANF secretion in response to pressure and volume overload.

Monocyte expression of tissue factor and adhesion molecules: the link with accelerated coronary artery disease in patients with chronic renal failure.

OBJECTIVE: To investigate the expression of monocyte tissue factor (MTF) and adhesion molecules in patients with chronic renal failure (CRF) and to look for any correlation with thrombin generation and Lp(a) lipoprotein. DESIGN: A study of MTF expression and adhesion molecules, prothrombin fragments 1+2 (PTf1+2), an index of thrombin generation, and lipoproteins in patients with CRF and in normal control subjects. BACKGROUND: Patients with end stage renal failure have an increased risk of coronary artery disease despite advances in therapy. Stimulated monocytes are potent activators of blood coagulation through the generation of MTF, which was recently implicated in the aetiology of acute coronary ischaemic syndromes. METHODS: MTF expression and adhesion molecules were measured in whole blood using immunofluorescence of monocytes labelled with anti-tissue factor antibody and CD11b and c by flow cytometry. PTf1+2 and Lp(a) lipoprotein in plasma were measured by enzyme linked immunosorbent assay (ELISA). PATIENTS: 70 patients with CRF without documented coronary artery disease (30 patients with CRF undialysed, 20 patients undergoing chronic ambulatory peritoneal dialysis (CAPD), and 20 undergoing haemodialysis (HD)), together with 20 normal controls, were studied. RESULTS: The (mean (SD)) increased MTF of CRF (48.0 (29) v 33.3 (7.2) mesf unit/100 monocytes in controls, p = 0.04) was more pronounced in patients undergoing dialysis (HD 73.1 (32.8) (p < 0.003) and CAPD 62.8 (28.9) mesf unit/100 monocytes, p < 0.04). MTF activity showed a positive correlation with both PTf1+2 and serum creatinine (p < 0.003) but not with Lp(a) lipoprotein. Lp(a) lipoprotein was significantly increased in both dialysis groups compared with controls (p < 0.005) and non-dialysis CRF groups (p < 0.02). Monocyte adhesion molecule (CD11b) was significantly higher in all three CRF groups than in the controls (p = 0.006). CONCLUSION: This study has demonstrated a hypercoagulable state in patients with CRF. This was especially pronounced in the dialysis patients. These findings provide a possible explanation for the increased cardiovascular and cerebrovascular morbidity and mortality in these patients.

External high frequency oscillation in normal subjects and in patients with acute respiratory failure.

External high frequency oscillation was performed on 20 healthy volunteers using a cuirass-based system, the Hayek Oscillator. Five-min periods of oscillation were carried out on each subject at frequencies of 1, 2, 3, 4 and 5 Hz. Effective ventilation was measured in terms of the fall in alveolar partial pressure of carbon dioxide immediately after oscillation. The optimum frequency for oscillation was 1-3 Hz but most of the subjects were adequately ventilated over a wide range of frequencies. Thus, the Hayek Oscillator is capable of adequately ventilating normal subjects by means of chest wall oscillation. We also compared external high frequency oscillation with intermittent positive pressure ventilation in five patients with respiratory failure. Using the same inspired oxygen fraction, the external high frequency oscillation replaced intermittent positive pressure ventilation for a 30-min period. External high frequency oscillation improved oxygenation by 16% and reduced the arterial carbon dioxide by 6%. These preliminary findings suggest that normal subjects and intensive care unit patients can be adequately ventilated by means of external high frequency oscillation.

Goal-directed therapy with dopexamine, dobutamine, and volume expansion: effects of systemic oxygen transport on hepatic ultrastructure in porcine sepsis.

OBJECTIVES: Can the hepatic structural deterioration that occurs during peritonitis be attenuated by increasing cardiac output and oxygen consumption (VO2)? Do the agents used to achieve these increases have any characteristic affects on these hepatic structural changes? DESIGN: Randomized, prospective, observational animal study. SETTING: Research laboratory of a university medical school. SUBJECTS: Twenty-five Middle White adolescent pigs, weighing 25 to 30 kg, divided into five groups. INTERVENTIONS: A thermodilution flotation catheter was advanced into the pulmonary artery. Additional catheters were inserted into the jugular, portal, and hepatic veins, and into the femoral artery. Ultrasound flow probes were placed around the portal vein and the hepatic artery. A metabolic cart was attached to the ventilator. Baseline measurements were made and cardiac output was increased by > 25% by administering either dobutamine (10 micrograms/min), dopexamine (10 micrograms/kg/min), or colloid. A control group had its cardiac output maintained at its baseline value. Peritonitis was induced in the four groups by contamination with cecal content and maintained for 6 hrs. Hepatic tissue was then removed for ultrastructural analysis and the animals were killed. MEASUREMENTS AND MAIN RESULTS: Before infection, cardiac output, VO2, and hepatic blood flow were increased in the three treatment groups. In the dobutamine and dopexamine groups, oxygen delivery increased, but decreased in the volume group. Mean arterial pressure increased in the dobutamine and dopexamine groups, but in the volume group, mean arterial pressure was maintained. Six hours after infection, cardiac output and VO2 had further increased in the dobutamine and volume groups, but both variables had decreased in the dopexamine group. After infection in the control group, cardiac output had decreased, although oxygen delivery and VO2 increased. There were no significant differences between hepatic hemodynamic or oxygen transport variables in any of the groups during the infection period. Hepatic ultrastructure was well maintained in the dopexamine group, while considerable deterioration was seen in the volume and control groups. In the dobutamine group, hepatic deterioration was greater than in the other three groups. CONCLUSIONS: Increasing cardiac output and VO2 before and during infection was only protective when dopexamine was administered. Dobutamine infusion was associated with greater hepatic deterioration than that effect seen in either the control or volume groups.

The Hayek oscillator. Nomograms for tidal volume and minute ventilation using external high frequency oscillation.

The Hayek Oscillator is a recent development in external high frequency ventilation and is a useful mode of ventilatory support during anaesthesia, in chronic respiratory failure and weaning in intensive care. The Hayek Oscillator is new and its application is growing, as are the number of patients who have benefited from its use. However, there are no clear guidelines on how best to adjust the oscillator to achieve optimum ventilation. A simple method of predicting changes in tidal volume and minute ventilation following adjustment would make the oscillator more useful. We present nomograms for tidal volume, minute ventilation and effective alveolar ventilation when the three variables, oscillator frequency, mean chamber pressure and peak-to-trough pressure span were adjusted. The frequency-tidal volume relationship was unaffected by a mean chamber pressure of 0, -5, -10 cmH2O, but altered with changes in peak-to-trough pressure span. We have also determined the effect of increasing negative extrathoracic pressure on functional residual capacity. The relationship between tidal volume and frequency was non-linear and related to the peak-to-trough pressure span. Mean functional residual capacity significantly increased from 2.25 l (SEM 0.10) without the cuirass at rest to 2.61 l (SEM 0.14) at -10 cmH2O (p < 0.05; n = 5) and 2.47 (SEM 0.12) at -20 cmH2O of mean chamber pressure. Vital capacity was unchanged by increasing extrathoracic pressure as was total lung capacity.

Dopexamine hydrochloride maintains portal blood flow and attenuates hepatic ultrastructural changes in a porcine peritonitis model of multiple system organ failure.

Fifteen anesthetised pigs (25-30 kg) were divided into three equal groups, sham, dopexamine (D) (10 micrograms/kg/min), and placebo (P). Sepsis was induced by fecal peritonitis in the D and P groups and colloid was infused to try to maintain mean arterial blood pressure (MABP) at a constant value and the hemodynamics measured at baseline and hourly for 8 hr. There was an initial increase in MABP and systemic vascular resistance (SVR) in the P group but not the dopexamine (D) group. Cardiac output (CO) in the P group showed a small decline but increased in the D group. The portal blood flow (PVF) in the P group fell with MABP but increased in the D group as MABP fell. The sham group showed normal ultrastructure and cellular integrity. Occlusion of the hepatic sinusoids was similar in the D and P groups. There was a greater area of Kupffer cells and endothelial cells in the P group, suggesting a greater inflammatory reaction than was found in the D group. Ultrastructure and mitochondrial integrity was better maintained in the D group. Dopexamine hydrochloride infusion maintained CO, increased PVF, and attenuated hepatic ultrastructural changes compared to placebo in a porcine fecal peritonitis model of multisystem organ failure.

Early results of intravascular oxygenation.

We have used the intravascular oxygenator (IVOX) in eight patients (14-76 years) with acute respiratory failure. At the time of referral for IVOX all patients were on inotropic support, five had pneumothoraces and two were on haemofiltration. Ventilatory data before IVOX were: ventilated for 2-14 days (median 6), PEEP 5-12 cm H2O (12), PIP 34-95 cm H2O (49), FiO2 0.7-1 (1), PaO2 5.4-26 KPa (8.5) and PaCO2 3.7-23 KPa (8). The intravascular oxygenator was used for 6 h-12 days (median 4), the oxygen transfer achieved was 68-140 ml/min (85) and the carbon dioxide removed was 40-106 ml/min (59). It was possible to decrease the ventilator settings with a significant increase in the PaO2 by 48 h (P < 0.05) but the fall in PaCO2 did not reach significance. As the IVOX was turned from "off" to "on" the mean PaO2 increase was 0.35 KPa +/- 0.14 SEM (P = 0.04) and the mean PaCO2 decrease 0.7 KPa +/- 0.2 SEM (P = 0.02) without any significant change in cardiac output. Two patients survived and six died from multisystem failure with three patients being hypoxic at the time of death. Postmortem examinations on five patients did not reveal any IVOX-related complications. We conclude that IVOX is safe but it is not as efficient in gas exchange as extracorporeal membrane oxygenation at present. Further improvement in the gas exchange efficiency of this prototype could render IVOX a very useful device.

Intravascular oxygenation with the IVOX.

Improvements in hollow fibre gas transfer membranes have enabled the development of an intravascular oxygenator which for the first time provides gas exchange without the need for an extracorporeal circuit. We describe all aspects of the clinical utilization of the intravascular oxygenator device.

A narrow range, medium molecular weight pentastarch reduces structural organ damage in a hyperdynamic porcine model of sepsis.

OBJECTIVE: to compare diafiltered 6% pentastarch (Pentafraction--PDP, MWn 120,000 and MWw 280,000) and native pentastarch (Pentaspan--PSP, MWn 63,000 and MWw 264,000 dalton) in a porcine model of faecal peritonitis. DESIGN: Randomised prospective study in 12 adolescent pigs. INTERVENTIONS: Prior to infection the study solution was infused to increase Qt by 25%. Thereafter adjustments in infusion rate were made (up to 1 l/h) in an attempt to maintain Qt at 25% above baseline values. MEASUREMENTS AND RESULTS: Animals were sacrificed at 8 h. Tissue was excised from the right lobe of liver and from the right lung and fixed for later electron microscopy and digital morphometric analysis. Patent sinusoidal lumen was significantly greater in group PDP compared to PSP (11.3% +/- 2.3% of liver tissue versus 4.8% +/- 1.1%, p < 0.05) and this was accounted for by a significantly lower proportion of sinusoidal lumen occluded with white cells (2.1% +/- 0.6% versus 6.6% +/- 1.9%, p < 0.05). Similarly, patent capillary represented a significantly higher proportion of lung tissue for group PDP versus PSP (26.2% +/- 1.9% versus 18.5% +/- 2.7%, p < 0.05). The arithmetic mean alveolar capillary barrier thickness was significantly greater in group PSP than in group PDP (4.3 +/- 0.3 microns versus 2.5 +/- 0.3 microns, p < 0.01). CONCLUSIONS: The molecular weight profile of Pentafraction was associated with less structural organ damage including less tissue oedema and less white cell occlusion.

Advantages of a narrow-range, medium molecular weight hydroxyethyl starch for volume maintenance in a porcine model of fecal peritonitis.

OBJECTIVE: To compare the effectiveness of two hydroxyethyl starch solutions of different molecular weight ranges for volume maintenance in a porcine model of fecal peritonitis. DESIGN: Randomized prospective trial. SETTING: Laboratory investigation. SUBJECTS: Adolescent female pigs weighing approximately 30 kg. INTERVENTIONS: We compared diafiltered 6% pentastarch with 6% high molecular weight hetastarch for volume maintenance in a porcine model of fecal peritonitis. The number average molecular weight of pentastarch is higher than hetastarch, although the weight average molecular weight is lower, i.e., a narrow range of medium weight molecules. The infusion rate of each agent was adjusted to maintain baseline arterial Hct for less than or equal to 7 hr after instrumentation and induction of fecal peritonitis. MAIN OUTCOME MEASUREMENTS: The volume of fluid required to maintain arterial Hct was compared along with comparisons of hemodynamic and histologic responses associated with the two agents. RESULTS: Significantly less pentastarch was required to prevent hemoconcentration than hetastarch (109 +/- 22.8 vs. 150 +/- 10.3 mL/kg; p less than .05) while hemodynamics, colloid osmotic pressure, and oxygen transport responses were similar. Capillary patency was greater (21.99 +/- 3.68 vs. 10.09 +/- 1.17%; p less than .05) and mean alveolar capillary barrier thickness was less (2.36 +/- 0.13 vs. 3.06 +/- 0.17 microns; p less than .05) with pentastarch than with hetastarch, as judged by electron microscopy. CONCLUSIONS: These data suggest that pentastarch is better retained in the circulation in capillary leak syndromes compared with hetastarch.