Influence of inorganic nutrition on growth and PSP toxin production of Alexandrium minutum (Dinophyceae) from Cork Harbour, Ireland.

The physiological response of the PSP toxin producing dinoflagellate Alexandrium minutum isolated from the Irish coast was assessed after modulating the initial concentrations of nitrate and phosphate in batch cultures. The cell growth in cultures of strain CK.A02 was primarily controlled by nitrate availability. In all experiments, only gonyautoxins 2 and 3 (GTX2 and 3) were synthesized along the different growth phases, with GTX3 dominating ( approximately 80%) at all stages, making the GTX2-3 toxin profile a possible population marker of A. minutum in Cork Harbour. The cellular toxin quotas remained low and relatively stable at around 2pgcell(-1), except when high N:P ratios were initially used for culture inoculations; in these conditions PSP toxins accumulated up to 14pgcell(-1). Due to the composition of the toxin profile, the toxicity of strain CK.A02 was generally relatively low (from 1.1 to 1.7pg STX eqcell(-1)) in comparison with strains from other geographic areas except when phosphate limiting culture conditions were applied (maximum of 12.5pg STX eqcell(-1)). Results showed that sufficient soluble protein quotas were necessary to observe the intra-cellular accumulation of PSP toxins in phosphate limiting conditions, highlighting also the requirement of adequate nitrogen supplies. The possible existence of localized toxicity hot spots in the field, linked to the accumulation of PSP toxins within A. minutum cells as a metabolic response to adverse environmental conditions, could potentially increase risks for shellfish farming operations.     

Trophic transfer of paralytic shellfish toxins from the cladoceran (Moina mongolica) to larvae of the fish (Sciaenops ocellatus).

The dynamic transmission and transformation of paralytic shellfish toxins (PSTs) from the toxic dinoflagellate Alexandrium tamarense to the cladoceran Moina mongolica and subsequently to the larvae of the fish Sciaenops ocellatus were investigated under laboratory conditions. The results showed that PSTs could be transferred to S. ocellatus when they preyed on PST-containing M. mongolica. During the experimental period, A. tamarense, M. mongolica and the digestive glands of the fish larvae contained C(1/2) toxins, and the viscera of S. ocellatus contained neoSTX. The proportion of beta toxin (C2) in C(1+2) toxins increased when PSTs were transferred from A. tamarense to M. mongolica, but in the subsequent transfer from M. mongolica to S. ocellatus the proportion of alpha toxin (C1) increased. During depuration, the contents of C1 and C2 toxins in fish larvae decreased with the duration of depuration, but neoSTX remained relatively constant. The present results indicated that, using a cladoceran as the vector, PSTs can be transferred from toxic algae to a high trophic level fish and metabolized in the fish. Future work should address the metabolic characteristics of PSTs in cladocerans and the end result when they are transferred to fishes.     

直肌肌束部分转位移植矫正麻痹性斜视的临床观察

目的 探讨直肌肌束部分转位移植矫正麻痹性斜视手术方法和治疗效果.方法 总结27例麻痹性斜视行直肌肌束部分转位移植,并观察在术前、术后麻痹肌的运动情况、双眼视功能、眼球运动情况、眼位及复视消失情况等结果.结果 27例患者术后眼球运动功能有不同程度好转,除2例外全部过中线,转动1～2mm者12例、3mm者10例、4～5mm者2例、7mm者1例.术后被转位的肌肉运动正常.术后21例患者不同程度恢复了双眼视功能,其中具备Ⅰ度双眼单视功能13例,具备Ⅱ度双眼单视功能6例,2例有Ⅲ度双眼单视功能.6例同视机检测仍是单眼抑制.术后眼位正位22例,欠矫5～10度5例,23例复视消除,3例轻度改变注视方向也可消除复视.1例仍有复视不能耐受行二次手术.结论 直肌肌束部分转位移植可矫正麻痹性斜视眼位,消除复视,改善眼球运动,恢复部分双眼视功能,而且睫状肌血管分离保留可减少眼前段供血不足的危险,是目前安全、可行、有效地手术方法.     

Determination of paralytic shellfish poisoning toxins in Norwegian shellfish by liquid chromatography with fluorescence and tandem mass spectrometry detection.

A novel extraction and clean-up method has been developed for the determination of paralytic shellfish poisoning (PSP) toxins in shellfish samples. Raw shellfish material was extracted with an acidic acetonitrile/water (80:20, v/v) solution, whilst being homogenised. During the homogenisation the sample extraction solution was cooled with ice water. Subsequently, the extract was frozen at -20 degrees C for at least 4h. During freezing, two layers were formed, only the lower predominantly aqueous layer was used for the determination. The final extract solution was cleaned-up using a combination of Oasis HLB and Carbograph activated carbon SPE columns. The developed extraction and clean-up methods combined with gradient elution liquid chromatography (LC)-mass spectrometry/mass spectrometry (MS/MS) has resulted in a method which can determine the analogs GTX 1-5, C1-2, DcGTX 2-3, DcSTX, Neo, STX in a single analysis with an overall detection limit of 313mug STXdiHCL-eq./kg shellfish meat. The use of the developed extraction method with post-column high performance liquid chromatography (HPLC) with fluorescence detection (FLD) method provided an overall limit of detection of 89mug STXdiHCL-eq./kg shellfish meat for the same toxins. Both post-column HPLC-FLD and LC-MS/MS was used to investigate the Norwegian PSP toxin profile. It was found that the PSP toxins could be detected in shellfish samples from the Norwegian coastline for 10 months of the year, from March till December. The toxin profile consisted mainly of the carbamate toxins, GTX 1-4, Neo and STX, in terms of both concentrations and contribution to the overall toxicity. In addition, several of the n-sulfo-carbamoyl toxins were either detected in the samples at relatively low concentrations or their presence in the samples were indicated but could not be confirmed by the post-column HPLC-FLD and LC-MS/MS analyses.     

Paralytic shellfish toxin profiles and toxin variability of the genus Alexandrium (Dinophyceae) isolated from the Southeast China Sea.

Paralytic shellfish toxin (PST) profiles of 16 Alexandrium isolates from the Southeast China Sea were analyzed by high-pressure liquid chromatography. Toxin content and composition of three A. tamarense isolates, ATDH01, ATGX02 and ATMJ02, were also investigated at different growth phases and under various culture conditions. Our results showed that six strains of A. affine were non-toxic, while 10 strains of A. tamarense and A. catenella were toxic. These toxic isolates grown in the same culture conditions consistently produced an unusually high proportion of the N-sulfocarbamoyl toxin C1/2 (around 60-80% of total toxins) and medium amounts of gonyautoxin GTX5 (around 15-30% of total) with only trace quantities (<5% of total) of other saxitoxin derivatives (i.e. GTX1, GTX3, GTX4 and neoSTX). The toxin composition of three A. tamarense isolates did not vary with the growth phases, although higher toxin contents (Qt, fmolcell(-1)) were found in the exponential phase. Variations in temperature, salinity and nutrient levels affected toxin content of three A. tamarense isolates but they did not have pronounced effects on the toxin composition (mole %). These results indicate that toxin composition remained relatively constant under various culture conditions, suggesting that toxin composition could be used as a stable biomarker for the Alexandrium species in this region. However, comparison of toxin profiles between isolates from different localities require special caution since isolates even from the same region can have distinct toxin profiles.     

森林脑炎瘫痪肌肉的肌电图研究

目的：观察森林脑炎病人瘫痪肌肉的肌电图（EMG）及神经传导速度的改变。方法：对30例森林脑炎病人的162块瘫痪肌肉进行常规肌电图检查及神经传导速度（NCV）的测定。结果：49（30．2％）块肌肉的运动单元电位（MUP）正常，未出现自发电位，神经传导速度正常；94（58．0％）块肌肉的运动单元电位显示时限延长、80（49．3％）块肌肉波幅增高，12（7．41％）块肌肉未引出运动单元电位，65（40．1％）块肌肉可见自发电位；7（4．3％）块肌肉的运动单元电位显示为时限缩短，随着病情的好转，运动单元电位显示为时限延长，波幅增高。102条神经中12（11．7％）条神经的运动传导速度（MCV）减慢，68条神经中4（5．8％）条神经的感觉传导速度（SCV）减慢。结论：森林脑炎病人的瘫痪原因为上运动神经元瘫痪和下运动神经元瘫痪．     

Development of quantitative NMR method with internal standard for the standard solutions of paralytic shellfish toxins and characterisation of gonyautoxin-5 and gonyautoxin-6

The chemical analysis of paralytic shellfish toxins (PSTs) requires standard solutions with accurate concentration. The mouse toxicity in each toxin is also essential knowledge for the introduction of chemical analysis as an alternative method to mouse bioassay (MBA) in routine monitoring of shellfish. In this study, we developed the quantitative analysis of PSTs by nuclear magnetic resonance (NMR), using tert-butanol as an internal standard. Only proton signals with longitudinal relaxation time (T₁) of less than 2.5 s, including the internal standard, were used for quantitation of toxins. Our method showed good precision (<3%) and accuracy (slope: 1.0038, R²: 1.0000). The limit of quantitation (LOQ) at 5% relative standard deviation (RSD) was calculated to be 0.16 mM, which corresponded to 67 μg/mL as Saxitoxin (STX) diacetate form, while the limit of detection (LOD) was 0.04 mM. Gonyautoxin-5 (GTX5) and gonyautoxin-6 (GTX6) isolated from mussels were quantified by our method, and the toxicities of GTX5 and GTX6 were obtained by the MBA in which mice were standardized by STX provided from FDA. The specific toxicities of GTX5 and GTX6 newly calculated by the MBA were 120 MU/μmol (29 μg STX equiv./μmol) and 105 MU/μmol (25 μg STX equiv./μmol), respectively. These results are useful to convert the amount of GTX5 and GTX6 into the mouse toxicity, especially in the areas where the dinoflagellate Gymnodinium catenatum predominantly produces both toxins.     

Paralytic shellfish poisoning: Seafood safety and human health perspectives

Paralytic shellfish poisoning (PSP) is the foodborne illness associated with the consumption of seafood products contaminated with the neurotoxins known collectively as saxitoxins (STXs). This family of neurotoxins binds to voltage-gated sodium channels, thereby attenuating action potentials by preventing the passage of sodium ions across the membrane. Symptoms include tingling, numbness, headaches, weakness and difficulty breathing. Medical treatment is to provide respiratory support, without which the prognosis can be fatal. To protect human health, seafood harvesting bans are in effect when toxins exceed a safe action level (typically 80 μg STX eq 100 g⁻¹ tissue). Though worldwide fatalities have occurred, successful management and monitoring programs have minimized PSP cases and associated deaths. Much is known about the toxin sources, primarily certain dinoflagellate species, and there is extensive information on toxin transfer to traditional vectors - filter-feeding molluscan bivalves. Non-traditional vectors, such as puffer fish and lobster, may also pose a risk. Rapid and reliable detection methods are critical for toxin monitoring in a wide range of matrices, and these methods must be appropriately validated for regulatory purposes. This paper highlights PSP seafood safety concerns, documented human cases, applied detection methods as well as monitoring and management strategies for preventing PSP-contaminated seafood products from entering the food supply.     

A rare and unsuspected complication of Clostridium difficile infection

Objective To report the occurrence of abdominal compartment syndrome (ACS) due to infection with Clostridium difficile. Design Case report. Setting Trauma intensive care unit (TICU) of Hamad General Hospital, a teaching hospital in Doha, Qatar. Patient A 36-year-old man involved in a motor vehicle accident had severe traumatic brain injury and received ceftriaxone. On day 7, he developed severe abdominal distension and diarrhoea followed by paralytic ileus with oliguria, hyperkalaemia, and intra-abdominal hypertension. The patient's stool sample was positive for C. difficile toxin A and B Measurements and results An ACS was diagnosed. The patient was successfully treated in the TICU by stopping the offending antibiotic and starting metronidazole plus neostigmine as a prokinetic agent. The fluid status was guided by pulse-induced continuous cardiac output, and frusemide was added to the treatment. With this aggressive management the abdominal pressure decreased and the renal function improved, with full recovery of renal function by day 21. Unfortunately the patient's Glasgow coma score (GCS) deteriorated, so percutaneous tracheostomy was performed. He was transferred to the neurosurgical ward on day 35. A week later he was shifted to the rehabilitation unit for further management. Conclusions C. difficile colitis can cause intra-abdominal hypertension (IAH) and ACS. Rapid diagnosis, early aggressive supportive care, metronidazole and prokinetics are necessary to lower the morbidity and mortality of C. difficile colitis associated with IAH and ACS. Presented as mini-paper at the 3rd World Congress on Abdominal Compartment Syndrome – WCACS 2007 [Shaikh N, Kettern MA, Elshaffie SS, Louon A, Hanssens Y (2007) Acta Clin Belg (Suppl) 62(1):287 (M9)].     

麻痹性脊柱侧凸的手术治疗策略

目的:探讨手术治疗麻痹性脊柱侧凸的一些问题.方法:通过对手术治疗的52例患者回顾性分析,就麻痹性脊柱侧凸的发病机理、临床特点及手术方式选择进行讨论.结果:所有病例的脊柱侧凸及骨盆倾斜均得到不同程度的纠正,以钉-棒系统矫正组疗效更佳.结论:手术治疗麻痹性脊柱侧凸时节段性脊柱固定器械(SSI)应为首选,对腰骶的固定及融合要慎重,随着脊柱侧凸畸形的矫正,骨盆倾斜会得到明显的纠正.