Detection of changes in cartilage water content using MRI T2-mapping in vivo

Objectives Osteoarthritis (OA) is the most prevalent chronic disease in the elderly, and it is generally diagnosed at an advanced state when treatment is difficult if not impossible. The early form of OA is characterized by an elevated water content in the cartilage tissue. The purpose of this study was to verify in vivo if changes in the water content of patellar cartilage typically occurring in early OA can be detected using T₂ mapping MRI methods.Design Twenty healthy volunteers performed 60 knee bends in order to compress their patellar cartilage thereby reducing its water content. MR images of the patellar cartilage were acquired immediately following exercise and after 45 min of rest. Patellar cartilage thickness and T₂ maps were determined and their difference between the time points evaluated.Results Cartilage thickness increased by 5.4±1.5% from 2.94±0.15 mm to 3.10±0.15 mm (P< 0.001) following 45 min of rest, while T₂ increased by 2.6±1.0% from 23.1±0.5 ms to 23.7±0.6 ms (P< 0.05).Conclusion Small, physiologic changes in the water content of patellar cartilage and the concomitant change in proteoglycan and collagen density following exercise can be detected using MRI. The proposed T₂-mapping method, together with other non-invasive MR cartilage imaging techniques, could aid in the early diagnosis of OA. Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved.     

Xenon preconditioning differently regulates p44/42 MAPK (ERK 1/2) and p46/54 MAPK (JNK 1/2 and 3) in vivo

Background. Xenon (Xe) induces preconditioning (PC) of the ratheart in vivo via activation of p38 mitogen-activated proteinkinase (MAPK). The role of ERK 1/2 and JNK 1/2 and 3 in Xe-PChas yet not been determined. Methods. For infarct size measurements, anaesthetized rats weresubjected to 25 min of coronary artery occlusion followed by120 min of reperfusion. Animals received Xe 70% during three5 min periods with and without the ERK inhibitor PD 98059 (1mg kg^–1, PD) or the JNK inhibitor SP 600125 (6 mg kg^–1,SP) (n=10 per group). Additional hearts were excised for westernblot and kinase activity assay: without further treatment, afterthe first, the second and the third period of Xe-PC or at theend of the last washout phase (n=4 each). Results. Infarct size (% of area at risk) was reduced from 46.2(8.1)% to 28.4 (11.3)% after Xe-PC (P<0.01). PD completelyabolished this effect [49.7 (11.4)%, P<0.01 vs Xe-PC]. Theratio of particulate/cytosolic phospho ERK 1/2 was time dependentlyincreased during the PC protocol [ERK 1: 15 min: 2.4 (1.2),25 min: 1.5 (0.3), 35 min: 1.6 (0.7), 45 min: 1.5 (0.5) vs Con1.0 (0.5) and ERK 2: 15 min: 3.3 (1.8), 25 min: 2.0 (1.5), 35min: 1.8 (1.7), 45 min: 0.9 (0.6) vs Con 0.8 (0.4)]. This findingwas confirmed by a non-radioactive MAPK activity assay. In contrastSP had no effect on Xe-PC and the phosphorylation state of JNKwas not influenced by Xe-PC. Conclusion. Besides the p38 MAPK, ERK 1/2 also is a mediatorof Xe-PC. However, JNK is not involved, demonstrating a highlyspecific regulation of different kinases during Xe-PC.      

Clinical relevance of the B12/N2O interaction A report of a seminar

The interaction of nitrous oxide and vitamin B₁₂ and its implications are not the exclusive territory of any one discipline. The initial discovery was by a chemist but it is of obvious relevance to anaesthetists and intensivists; some complications are neurological others haematological. The interaction provides an extremely important research tool as the first easily available B₁₂-deficient animal model. Finally there are implications for exposure to contaminated atmospheres in hospitals and in industry.     

H2 antagonists and bupivacaine clearance

The effect of the H2 receptor antagonists cimetidine and ranitidine on bupivacaine clearance was assessed in women scheduled to undergo elective Caesarean section under epidural anaesthesia. Thirty-six women were randomly allocated to receive either no medication, cimetidine 400 mg or ranitidine 150 mg on the night prior to and on the morning of surgery. No significant difference was found between the peak bupivacaine levels: the mean (SD) values were 0.74 (0.17) microgram/ml, 0.81 (0.38) microgram/ml and 0.70 (0.24) microgram/ml in the control, cimetidine and ranitidine groups, respectively. Similarly, the H2 receptor antagonists did not alter the plasma bupivacaine against time curves, half-life or bupivacaine clearance in the three groups studied.     

Effects of esmolol on haemodynamic response to CO2 pneumoperitoneum for laparoscopic surgery

Background : Carbon dioxide (CO₂) pneumoperitoneum for laparoscopic surgery increases arterial pressures, systemic vascular resistance and heart rate and decreases urine output.
Methods : In this double-blind randomized study esmolol, an ultrashort-acting β1-adrenoceptor antagonist was compared with physiological saline (control) in 28 patients undergoing laparoscopic surgery in standardized 1 MAC isoflurane anaesthesia. Alfentanil infusion was used to prevent the increase of mean arterial pressure more than 25% from baseline.
Results : Esmolol effectively prevented the pressor response to induction and maintenance of CO₂ pneumoperitoneum. Significantly ( P <0.001) less alfentanil was needed in the esmolol group than in the control group. Urine output was higher ( P <0.05) and plasma renin activity ( P <0.01) and urine N-acetyl-β-D-glucosaminidase levels lower in the esmolol group when compared with the control group.
Conclusions : Esmolol blunts the pressor response to induction and maintenance of pneumoperitoneum and may protect against renal ischaemia during pneumoperitoneum.     

A Comparison of Intravenous Sedation With Two Doses of Dexmedetomidine: 0.2?μg/kg/hr Versus 0.4?μg/kg/hr

The present study investigated the physiologic and sedative effects between two different continuous infusion doses of dexmedetomidine (DEX). Thirteen subjects were separately sedated with DEX at a continuous infusion dose of 0.2 µg/kg/hr for 25 minutes after a loading dose of 6 µg/kg/hr for 5 minutes (0.2 group) and a continuous infusion dose of 0.4 µg/kg/hr for 25 minutes after a loading dose of 6 µg/kg/hr for 5 minutes (0.4 group). The recovery process was then observed for 60 minutes post infusion. The tidal volume, mean arterial pressure, and heart rate in both groups decreased significantly during infusion, but they were within a clinically acceptable level. A Trieger dot test plot error ratio in the 0.4 group was significantly higher than that in the 0.2 group until 15 minutes post infusion. Sedation appears to be safe at the infusion doses of DEX studied. However, increasing maintenance infusion doses of DEX from 0.2 µg/kg/hr to 0.4 µg/kg/hr delays some recovery parameters.     

The potential for increased risk of infection due to the reuse of convective air-warming/cooling coverlets

BACKGROUND: The use of convective air warming and/or cooling for the prevention of hypothermia or to induce hypothermia is growing rapidly. To date, there is no information available as to the potential risks for infection associated with either the post-surgical reuse or the repositioning of coverlets closer to the wound. We hypothesized that use of coverlets either intra- or postoperatively leads to increased contamination. METHODS: The bacterial contamination of commercially available coverlets before (control group, n = 10) and after patient application (n = 18) was investigated. From 3 predetermined sites, 1 cm x 2 cm pieces of coverlet were removed and analyzed for bacterial contamination. RESULTS: Even prior to use, coverlet samplings provided identifiable contamination (3 out of 30 sites, 10%), but this could be within our study's sampling error. Nevertheless, following clinical use the frequency of contamination was considerably increased; 17 out of 57 sampled sites (31.5%) elicited contamination (P < 0.05, Fisher's exact test). CONCLUSION: This study demonstrates that the use of the coverlets, intra- or postoperatively, can lead to significant bacterial contamination. It is concluded that it is not advisable to reuse coverlets for multiple clinical applications.     

HES 130/0.42 shows less alteration of pharmacokinetics than HES 200/0.5 when dosed repeatedly

Background: Hydroxyethyl starches (HES) accumulate in the circulation whenadministered repeatedly. Accumulation is thought to be partlyresponsible for undesirable effects (tissue storage, blood coagulationimpairment, and itching). HES 130/0.42 with low molecular weightand a low level of substitution has recently been developedin order to reduce those risks. Methods: In healthy volunteers, the pharmacokinetics of HES 130/0.42/6:1were investigated using a crossover design with HES 200/0.5serving as control. Fifty grams of either HES were administeredin 4 h day^–1 for a period of five consecutive days. HESserum concentrations were used for computation of pharmacokineticcoefficients. Change between the first and fifth infusion inthe area under the concentration curve (AUC) served as the primarymeasurement. Results: Although the circulation was freed from the load with HES 130/0.42within 20 h after end of the previous infusion, the amount ofHES 200/0.5 increased continuously from one administration tothe other. AUC and elimination half-life (t_1/2) were significantlylower with HES 130/0.42. AUC and t_1/2 of HES 200/0.5 showedan increase between the first and the fifth administration whereasonly a minimal shift was present with HES 130/0.42. Haemodilutionvia HES 200/0.5 did not change over time. Conclusions: Repeated administration of HES 130/0.42 shows no accumulationand fewer tendencies to time-dependent changes in pharmacokineticparameters than HES 200/0.5. The improved reproducibility mayimprove drug safety, particularly as the accumulation of residualstarch with HES 200/0.5 does not contribute to the colloid'svolume effect, but may rather increase the risk of undesiredreactions.     

A randomised trial comparing 5 mL/kg and 10 mL/kg of pentastarch as a volume preload before spinal anaesthesia for elective caesarean section

BACKGROUND: Colloid solutions are more effective at preventing hypotension than crystalloids when used as a volume preload before caesarean delivery under spinal anaesthesia. The ideal volume to infuse has not been established. METHOD: In a randomised double-blind trial 70 women presenting for elective caesarean section received either 5 mL/kg of pentastarch (group A) or 10 mL/kg of pentastarch (group B) as a volume preload before spinal anaesthesia. Hypotension was defined as a systolic pressure below 90 mmHg or a decrease of 30% from a baseline value. Treatment was with 6-mg increments of ephedrine until resolution. RESULTS: In group B, 7/35 patients (20%) developed hypotension, significantly fewer than the 15/35 (42.8%) in group A (P<0.05). The patients in group B also required less ephedrine (total in group, 114 mg) than those in group A (total in group, 198 mg) CONCLUSIONS: Pentastarch, 10 mL/kg is more effective than 5 mL/kg at preventing hypotension following spinal anaesthesia for caesarean delivery.     

Comparison of articaine and bupivacaine/lidocaine for sub-Tenon's anaesthesia in cataract extraction

Background. Articaine is the most widely used local anaestheticfor dental anaesthesia in Germany, Italy and The Netherlandsand has recently been introduced and licensed for dental usein the UK. We have previously shown articaine to be superiorto a standard mixture of bupivacaine 0.5%/lidocaine 2% for peribulbaranaesthesia. Sub-Tenon’s anaesthesia arguably providesa safer method of anaesthetic delivery for cataract surgery.A blunt cannula is used in this technique, thus greatly reducingthe risk of globe perforation, intrathecal injection and sight-threateningperiocular haemorrhage. Methods. We compared articaine and bupivacaine/lidocaine forsub-Tenon’s anaesthesia in cataract surgery. Results. Sub-Tenon’s anaesthesia using articaine 2% resultedin a more rapid onset of motor block compared with a bupivacaine/lidocaine(P=0.0076). Ocular movement scores were significantly lowerfrom 2 min after injection until the end of surgery (P=0.031ANOVA). Conclusion. Articaine 2% is safe and effective for sub-Tenon’sanaesthesia and is a suitable alternative to the traditionalbupivacaine 0.5%/lidocaine 2% mixture. Br J Anaesth 2004; 92: 228–30     

Successful bowel surgery at hemoglobin 2 g/dL without blood transfusion

We were unable to find reports in the published medical literature of any cases of bowel surgery being successfully performed at such a low hemoglobin level,without blood transfusion or blood products pre or post-surgery,with the patient’s uncomplicated recovery.This study is about such a case.A patient presenting with severegastrointestinal bleeding was diagnosed with enteric fever and multiple ileal ulcers.He had an extremely low hemoglobin level(2 g/dL) and mild renal and hepatic impairment.He was immediately admitted for right hemicolectomy under general anesthesia though he refused transfusion of blood or blood products prior to,during,or after surgery on religious grounds(Jehovah’ s Witnesses).After the surgery and having survived these potentially life-threatening circumstances,he left the hospital without major complications.In such circumstances,lives may be saved by prompt clinical decision-making,collaboration and swift surgical intervention coupled with the immediate consultation and input of the patient and family.     

Octreotide Ameliorates Renal Ischemia/Reperfusion Injury via Antioxidation and Anti-inflammation

Oxidative stress, calcium overload, inflammation, cellular necrosis, and apoptosis are implicated in renal ischemic/reperfusion injury (RIRI). Because octreotide (OCT) is protective in retinal IRI, the effect of OCT on mouse RIRI and the mechanisms involved were investigated. The RIRI model was induced in male C57BL/6 mice, and the mice were then treated with saline or OCT. Serum and kidneys were subjected to periodic acid–Schiff staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, enzyme-linked immunosorbent assay, western blotting, and immunohistochemistry. Treatment with OCT restored the renal functions and histologic changes induced by RIRI. The administration of OCT reduced tumor necrosis factor–α and interleukin-6 levels in kidney tissues, protected the kidney from apoptosis, and significantly downregulated the expression of nuclear factor–κB p65. In addition, OCT treatment upregulated the expression of nuclear factor erythroid 2–related factor 2, heme oxygenase–1, and NAD(P)H quinone oxidoreductase 1 and enhanced the renal antioxidant capacity. These results cumulatively indicate that OCT may protect the kidneys against IRI in a mouse model through the regulation of antioxidation and anti-inflammation.     

CT诊断结节/肿块型肺结核

目的探讨结节或肿块型肺结核的CT特征。方法收集接受CT检查并经病理证实的结节/肿块型肺结核患者56例,分析其病灶的CT特点。结果 56例患者中结节/肿块边缘呈分叶26例、毛刺11例、边缘光整19例;内部空洞9例、空泡6例、点状钙化9例;胸膜牵拉、凹陷征6例;支气管充气征2例,支气管狭窄、管壁增厚22例,支气管截断5例,支气管扩张2例;伴随树芽征11例,反晕征4例,淋巴结肿大10例,淋巴结钙化11例,少量胸腔积液1例。CT呈不均匀强化伴内部多发类圆形坏死区10例,均匀强化1例。结论结节/肿块型肺结核的CT征象分析有助于其诊断和鉴别诊断,对不典型肺结核的早期诊断有一定意义。     

HIT/HITT and alternative anticoagulation: current concepts

Br J Anaesth 2003; 90: 676–85     

慢性肿块型胰腺炎的18F-FDG PET/CT影像学表现

目的探讨慢性肿块型胰腺炎18F-FDG PET/CT影像学表现。方法回顾性分析6例经手术病理证实的慢性肿块型胰腺炎的18F-FDG PET/CT影像资料和临床资料。结果 6例共检出6个病灶,3个位于胰头,3个位于胰尾;平均大小3.0cm×2.7cm。CT平扫6个病灶呈均匀等密度,未见钙化灶,平均CT值约为36HU;增强扫描全部病灶呈延迟期强化。全部病灶18F-FDG摄取呈局灶性增高,最大标准摄取值（SUVmax）1.6～5.3,平均SUVmax3.92±1.49,高于正常胰腺组织的2.05±0.39（t=-3.648,P=0.015）。3例病灶累及胰头,胆总管及胰管不同程度扩张,呈双管征,胰体尾部轻度萎缩;3例病灶累及胰尾,胆总管及胰管未见扩张,胰体尾部未见萎缩。病灶邻近的主要血管均未受侵。全部病例胰周及腹膜后淋巴结未见18F-FDG局灶性摄取增高,未见远处脏器或（和）组织转移。结论 18 F-FDG PET/CT对诊断慢性肿块型胰腺炎具有一定价值。     

Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children

Background. The ilioinguinal/iliohypogastric nerve block isa popular regional anaesthetic technique for children undergoinginguinal surgery. The success rate is only 70–80% andcomplications may occur. A prospective randomized double-blindedstudy was designed to compare the use of ultrasonography withthe conventional ilioinguinal/iliohypogastric nerve block technique. Methods. One hundred children (age range, 1 month–8 years)scheduled for inguinal hernia repair, orchidopexy or hydrocelerepair were included in the study. Following induction of generalanaesthesia, the children received an ilioinguinal/iliohypogastricblock performed either under ultrasound guidance using levobupivacaine0.25% until both nerves were surrounded by the local anaestheticor by the conventional ‘fascial click’ method usinglevobupivacaine 0.25% (0.3 ml kg^–1). Additional intra-and postoperative analgesic requirements were recorded. Results. Ultrasonographic visualization of the ilioinguinal/iliohypogastricnerves was possible in all cases. The amount of local anaestheticused in the ultrasound group was significantly lower than inthe ‘fascial click’ group (0.19 (SD 0.05) ml kg^–1vs 0.3 ml kg^–1, P<0.0001). During the intraoperativeperiod 4% of the children in the ultrasound group received additionalanalgesics compared with 26% in the fascial click group (P=0.004).Only three children (6%) in the ultrasound-guided group neededpostoperative rectal acetaminophen compared with 20 children(40%) in the fascial click group (P<0.0001). Conclusions. Ultrasound-guided ilioinguinal/iliohypogastricnerve blocks can be achieved with significantly smaller volumesof local anaesthetics. The intra- and postoperative requirementsfor additional analgesia are significantly lower than with theconventional method.      

Analgesia after day case laparoscopic sterilisation#A comparison of tramadol with paracetamol/dextropropoxyphene and paracetamol/codeine combinations

In a prospective, double-blind trial we compared the analgesic efficacy of tramadol during the first 24 h after day case laparoscopic sterilisation with two commonly prescribed combination analgesics. Seventy-five women were allocated randomly to receive oral paracetamol 325 mg/dextropropoxyphene hydrochloride 32.5 mg, tramadol 50 mg or paracetamol 500 mg/codeine phosphate 30 mg as required after a standardised anaesthetic technique. There were no significant differences in average or worst pain, sleep disturbance, mobility, number of tablets taken, satisfaction or preference for stronger analgesia (26.2% of all patients). The incidences of nausea and vomiting were comparable between groups. There was a trend towards a lower incidence of central nervous system side-effects (drowsiness, dizziness, headache) in the paracetamol/codeine group. Tramadol may be considered an alternative analgesic for day case surgery although analgesic regimens of greater efficacy are required for many patients. The relative incidence of side-effects for tramadol and other analgesics requires further evaluation.     

Comparison of the novel hydroxyethylstarch 130/0.4 and hydroxyethylstarch 200/0.6 in brain-dead donor resuscitation on renal function after transplantation

BACKGROUND: The renal effect of hydroxyethylstarch (HES) solutions remains controversial. We hypothesized that the use of HES with a mean molecular weight of 130 kDa would reduce renal dysfunctions in the recipients. Our study was aimed at comparing the effects of two fluid regimens (HES 130/0.4 or HES 200/0.6) used for the resuscitation of brain-dead donors on the rate of delayed graft function (DGF) and the serum creatinine levels post-transplantation. METHODS: This retrospective matched-paired study was conducted in an intensive care unit of a university hospital. Case-controls were matched at the donor patient level as follows: gender, BMI, duration of ICU stay, serum creatinine levels, vasopressor, and volume of colloids. The organ donation from 64 brain-dead donors resulted in 115 transplants. RESULTS: The renal function was similar among all donors. The characteristics of the recipients, including the cold ischaemia time, were similar. The rate of DGF was 22% in the donors treated with HES 130/0.4, compared with 33% in those treated with HES 200/0.6 (P=0.27). The serum creatinine levels at 1 month were 133 (38) micromol litre(-1) when the donors had been treated with HES 130/0.4 and 172 (83) micromol litre(-1) when they were treated with HES 200/0.6 (P=0.005). A difference was found 1 yr after transplantation [128 (36) vs147 (43) micromol litre(-1), P=0.05]. CONCLUSIONS: Using a modern, third-generation, rapidly degradable HES preparation with a low degree of substitution seems to be associated with a better effect on the renal function of recipients.     

Expanding role of 18F-fluoro-d-deoxyglucose PET and PET/CT in spinal infections

¹⁸F-fluoro-d-deoxyglucose positron emission tomography ([¹⁸F]-FDG PET) is successfully employed as a molecular imaging technique in oncology, and has become a promising imaging modality in the field of infection. The non-invasive diagnosis of spinal infections (SI) has been a challenge for physicians for many years. Morphological imaging modalities such as conventional radiography, computed tomography (CT), and magnetic resonance imaging (MRI) are techniques frequently used in patients with SI. However, these methods are sometimes non-specific, and difficulties in differentiating infectious from degenerative end-plate abnormalities or postoperative changes can occur. Moreover, in contrast to CT and MRI, FDG uptake in PET is not hampered by metallic implant-associated artifacts. Conventional radionuclide imaging tests, such as bone scintigraphy, labeled leukocyte, and gallium scanning, suffer from relatively poor spatial resolution and lack sensitivity, specificity, or both. Initial data show that [¹⁸F]-FDG PET is an emerging imaging technique for diagnosing SI. [¹⁸F]-FDG PET appears to be especially helpful in those cases in which MRI cannot be performed or is non-diagnostic, and as an adjunct in patients in whom the diagnosis is inconclusive. The article reviews the currently available literature on [¹⁸F]-FDG PET and PET/CT in the diagnosis of SI.     

Tissue/blood and tissue/water partition coefficients for propofol in sheep

The primary objective of this study was to determine in vivotissue/blood partition coefficients of propofol for use in physiologicalmodelling of its pharmacokinetics. The sheep was used as ananimal model. In the main series of experiments, crossbred ewesreceived a bolus of propofol 1% (Diprivan) followed by an infusionduring which blood concentrations were measured at intervals.After 2 h, the sheep were killed with an injection of potassiumchloride, and tissue samples were taken for storage at –20°Cand subsequent analysis. Tissue/blood partition coefficientsdepend on the amount of triglyceride which accumulates in bloodfrom the propofol vehicle; for blood, free of added triglyceride,the following coefficients were calculated: brain, 3.23; heart,5.94; kidney, 2.46; spleen, 1.86; semimembranosus muscle,