How long does it take to coil an intracranial aneurysm?

Introduction The change in the treatment of choice for intracranial aneurysms from clipping to coiling has been associated with an important change in logistics. The time needed for coiling is variable and depends on many factors. In this study, we assessed the procedural time for the coiling of 642 aneurysms and tried to identify predictors of a long procedural time. Methods The procedural time for coiling was defined as the number of minutes between the first diagnostic angiographic run and the last angiographic run after embolization. Thus, induction of general anesthesia and catheterization of the first vessel were not included in the procedural time. A long procedural time was defined as the upper quartile of procedural times (70–158 min). Logistic regression analysis was performed for several variables. Results The mean procedural time was 57.3 min (median 52 min, range 15–158 min). More than half of the coiling procedures lasted between 30 and 60 min. Multiple logistic regression analysis identified the use of a supportive device (OR 5.4), procedural morbidity (OR 4.5) and large aneurysm size (OR 3.0) as independent predictors of a long procedural time. A poor clinical condition of the patient, the rupture status of the aneurysm, gender, the occurrence of procedural rupture, and aneurysm location were not related to a long procedural time. The mean time for the first 321 coiling procedures was not statistically significantly different from mean time for the last 321 procedures. Conclusion With optimal logistics, coiling of most intracranial aneurysms can be performed in one to two hours, including patient handling before and after the actual coiling procedure.     

Estimating time of death based on the biological clock

The biological clock may stop at the time of death in a dead body. Therefore, the biological clock seems useful for estimating the time of death. In this study, we tried to read the biological clock in tissues from dead bodies to estimate the time of death using molecular biological techniques. At first, we examined real-time RT-PCR analysis of gene expression for mPer2 and mBmal1, which constitutes a feedback loop in the oscillation system, in the kidney, liver, and heart of mice. We could detect circadian oscillation of these gene expressions in mouse tissues even at <48 h after death. Thus, the ratio of mPer2/mBmal1 was found to be useful for estimating the time of death. We next applied this method to the liver, kidney, and heart obtained from forensic autopsy cases with less than 72 h of postmortem interval. Significant circadian oscillation of hPer2/hBmal1 ratio could be detected in these autopsy samples. We further examined gene expression for hRev-Erbα, a component of another feedback loop. The ratios of hRev-Erbα/hBmal1 showed higher amplitude of oscillation than those of hPer2/hBmal1 and are considered more suitable for estimating the time of death. In particular, a hRev/hBmal1 ratio of >50 indicated the time of death as 0200–0900 hours, and a hRev/hBmal1 ratio that considerably exceeded 75 indicated the time of death as 0200–0800 hours. On the other hand, a hRev/hBmal1 ratio of less than 25 strongly indicated the time of death as 1000–2300 hours. Taken together, these findings indicate that gene expression analyses of the biological clock could be powerful methods for estimation of the time of death.     

Blood platelet count and severity of decompression sickness in rats after a provocative dive

INTRODUCTION: Previous animal studies reported that platelet count (PC) is decreased following decompression. Adherence and aggregation of platelets to the bubble surface has been demonstrated in severe decompression sickness (DCS). The present study was designed to clarify the relationship between post-dive platelet levels and the severity of DCS in a rat model. METHODS: A total of 57 male Sprague-Dawley rats were assigned to either one experimental group with a hyperbaric exposure (N = 22) or one control group (N = 27). Rats were compressed to 1000 kPa (90 msw) for 45 min while breathing air and decompressed to surface in 38 min with stops at 200, 160, and 130 kPa. Onset of neurological DCS and death time were recorded during a 120-min observation period after surfacing. In the control group, rats were maintained at atmospheric pressure in the same chamber for an equivalent period of time. Blood samples for PC were taken 30 min before and immediately after exposure in two groups. RESULTS: Blood PC after hyperbaric exposure had significantly decreased, whereas PC had increased in the control group. We found a correlation between % fall in PC and latency to death time. The platelet loss tended to decrease when fatal DCS was delayed. Rats suffering from severe DCS with a short latency to death presented a pronounced decline in platelets. DISCUSSION: The present study highlighted a relationship between the post-dive decrease in PC and DCS severity in rats. Platelet consumption could offer a new index for evaluating decompression stress.     

Peripheral nerve stimulation properties of head and body gradient coils of various sizes

Peripheral nerve stimulation (PNS) caused by time-varying magnetic fields has been studied both theoretically and experimentally. A human volunteer study performed on three different body-size gradient coils and one head-size gradient coil is presented in this work. The experimental results were used to generate average PNS threshold parameters for the tested gradient systems. It was found that the average stimulation threshold increases while gradient-region-of-uniformity size decreases. In addition, linear relationships between PNS parameters and diameter of homogeneous gradient spherical volume (DSV) were discovered: SR(min) and DeltaG(min) both vary inverse linearly with DSV. More importantly, the chronaxie value was found to vary inversely linearly with the DSV. This finding indicates that, contrary to the general understanding, the parameter "chronaxie" in the commonly accepted simple stimulation models cannot be considered to be a single-value, nerve-specific constant. A modified linear model for gradient-induced PNS based on these results was developed, which may permit, for the first time, the general prediction of nerve stimulation properties for gradient coils of arbitrary linear region dimension.     

Fatal overdose with a combination of SNRIs venlafaxine and duloxetine

Drugs for the treatment of depressive disorders, including SNRIs (serotonin noradrenaline reuptake inhibitors) venlafaxine and duloxetine, are widely prescribed as they have a high therapeutic to toxicity ratio. In rare cases, adverse effects may be severe, usually due to iatrogenic, accidental or intentional self-overdose that cause the excessive accumulation of serotonin and noradrenaline in synaptic clefts. Lethal intoxication with a combination of venlafaxine and duloxetine (postmortem blood concentrations 24 mg/L and 0.97 mg/L, respectively) without co-ingested substances, comorbidities or injuries that could have an unknown contribution to a fatal outcome is presented for the first time in the following case report, with a comprehensive clinical history, and complete results of the performed analyses. The cause of death was a serotonin syndrome that progressed to death in approximately six hours and 15 min after the suicidal ingestion of venlafaxine and duloxetine. Despite the high therapeutic to toxicity ratio SNRIs, which are reserved for patients with severe forms of depressive disorders and a higher suicidal tendency, they should be cautiously prescribed and handed over in smaller packages to make them easier to follow, and thus avoid accumulation within the patient’s reach.     

Gadolinium-ethoxybenzyl-DTPA as a hepatobiliary contrast agent for use in MR cholangiography: results of an in vivo phase-I clinical evaluation

The purpose of this study was to investigate the time course of contrast enhancement in bile ducts and the gallbladder (GB) after injection of gadolinium-ethoxybenzyl-DTPA (Gd-EOB-DTPA). In a clinical phase-I study, MR imaging at 1.5T was performed in 16 healthy volunteers with four different doses of Gd-EOB-DTPA (10, 25, 50, and 100 μmol/kg b. w., four volunteers per dosage). The study protocol comprised a heavily T1-weighted fast multiplanar gradient-echo (GE) sequence before and at increasing intervals for up to 360 min after injection of Gd-EOB-DTPA. The signal enhancement was evaluated in extra- and intrahepatic bile ducts as well as in the GB. In all 16 volunteers the common bile duct showed intense signal enhancement beginning 5–16 min after injection (mean 10 min) and persisting for at least 120 min in 4 subjects and for 360 min in 12 subjects. The duration of signal enhancement was significantly (p < 0.05) longer for higher doses (50, 100 μmol/kg) than for lower doses (10, 25 μmol/kg). Intrahepatic bile ducts were hyperintense as compared with liver parenchyma in all subjects receiving 10 μmol/kg from approximately 50–120 min after contrast agent application. Intrahepatic bile ducts were not displayed using the higher doses, probably because of the strong enhancement of the liver parenchyma. Gallbladder contrasting was achieved in all cases beginning 7–33 min after injection (mean 19 min) and remained visible for up to 360 min in 94 %. Hyperintense visualization of normal extrahepatic bile ducts as well as the GB is regularly achieved with the hepatobiliary contrast agent Gd-EOB-DTPA. The dosage for hyperintense visualization of intrahepatic bile ducts is 10 μmol/kg. Received 6 December 1995; Revision received 21 March 1996; Accepted 25 March 1996     

Vectorized photosensitizers to target,detect and treat peritoneal metastases by photodynamic therapy

60% of women with epithelial ovarian cancer relapse after conventional treatment, which combines complete macroscopic cytoreduction surgery (CRS) with platinum salt-based chemotherapy. This high recurrence rate is believed to be strongly related to the presence of microscopic residues at the end of surgery. It is essential to detect and treat these microscopic peritoneal metastases after macroscopic CRS, in order to limit their occurrence and thus increase the survival of the patients after treatment. Folate Receptor α (FR) shows promising prospects in targeting ovarian cancerous cells. Folic acid (FA) targeted photosensitizer could be used in intraperitoneal PDT that could be an innovative add-on therapy to macroscopic cytoreductive surgery to treat microscopic peritoneal metastasis.A disadvantage of FA is that it undergoes structure decomposition upon illumination. In order to avoid this decomposition, we designed and developed modified FA. We performed rational changes based on our own expertise and on systematic molecular docking in parallel. These modifications are also considered based on the known interactions between folic acid and FRα.A first FA analog was synthesized and coupled with pyropheophorbide a. The final product was obtained after 9 synthesis steps and with an overall yield of 10%. The study of its photophysical properties was performed and showed similarity with those of free pyropheophorbide a.The first biological analyses showed an absence of dark toxicity of this new analogue for various ovarian cancer cell lines. Moreover, its efficiency in PDT was demonstrated by the induction of cell death at a concentration of 1.8 μM, with 5 min illumination we could observe 60% cell death 24h after PDT and with a concentration of 9 μM, with 60 min illumination, 100 % cell death 24h after PDT.     

Aperistaltic effect of hyoscine N-butylbromide versus glucagon on the small bowel assessed by magnetic resonance imaging

The aim of this prospective study was to compare the intraindividual aperistaltic effect of 40 mg hyoscine N-butylbromide (HBB/Buscopan) with that of 1 mg glucagon on small bowel motility by using magnetic resonance imaging (MRI). Ten healthy volunteers underwent two separate 1.5-T MRI studies (HBB/glucagon) after a standardized oral preparation with an aqueous solution of Gd-DOTA and ispaghula (Metamucil). A 2D T1-w GRE sequence was acquired (TR 2.7 ms/TE 1.3 ms, temporal resolution 0.25 s) before and after intravenous (i.v.) drug administration and motility was followed over 1 h. On the resulting images the cross-sectional luminal diameters were assessed and plotted over time. Baseline motility frequency, onset of aperistalsis, duration of arrest, reappearance of motility and return to normal motility were analysed. Significant differences regarding reliability and duration of aperistalsis were observed. In the HBB group aperistalsis lasted a mean of 6.8 ± 5.3 min compared with 18.3 ± 7 min after glucagon (p < 0.0001). In 50% of cases HBB did not accomplish aperistalsis, whereas glucagon always succeeded (p = 0.05). There were no significant differences in terms of baseline and end frequencies for the onset of aperistalsis (22.2 ± 37.5 s HBB/13.4 ± 9.2 s glucagon, p = 0.1), nor for the return to normal motility. Arrest of small bowel motion is achieved more reliably and lasts significantly longer after i.v. administration of 1 mg glucagon compared with 40 mg HBB.     

Rectal temperature-based death time estimation in infants

In determining the time of death in infants based on rectal temperature, the same methods used in adults are generally used. However, whether the methods for adults are suitable for infants is unclear. In this study, we examined the following 3 methods in 20 infant death cases: computer simulation of rectal temperature based on the infinite cylinder model (Ohno’s method), computer-based double exponential approximation based on Marshall and Hoare’s double exponential model with Henssge’s parameter determination (Henssge’s method), and computer-based collinear approximation based on extrapolation of the rectal temperature curve (collinear approximation). The interval between the last time the infant was seen alive and the time that he/she was found dead was defined as the death time interval and compared with the estimated time of death. In Ohno’s method, 7 cases were within the death time interval, and the average deviation in the other 12 cases was approximately 80 min. The results of both Henssge’s method and collinear approximation were apparently inferior to the results of Ohno’s method. The corrective factor was set within the range of 0.7–1.3 in Henssge’s method, and a modified program was newly developed to make it possible to change the corrective factors. Modification A, in which the upper limit of the corrective factor range was set as the maximum value in each body weight, produced the best results: 8 cases were within the death time interval, and the average deviation in the other 12 cases was approximately 80 min. There was a possibility that the influence of thermal isolation on the actual infants was stronger than that previously shown by Henssge. We conclude that Ohno’s method and Modification A are useful for death time estimation in infants. However, it is important to accept the estimated time of death with certain latitude considering other circumstances.     

Development of an accelerated MSCT protocol (Triage MSCT) for mass casualty incidents: comparison to MSCT for single-trauma patients

During multiple casualty incidents (MCI) emergency radiology departments have to deal with a large number of patients with suspected severe trauma within a short period of time. The aim of this study was to develop a suitable accelerated multislice computed tomography (MSCT) protocol to increase patient throughput for this kind of emergency situation. We presumed a scenario of 15 patients being admitted to the trauma service with suspicion of severe injuries after a MCI over a period of 2 h. An accelerated Triage MSCT protocol was developed and evaluated for MSCT scanner productivity (patients per hour) and time (minutes) needed for a total MSCT body workup using an anthropomorphic phantom. In addition, time (minutes) for transfer and preparation was measured. These timeframes were compared to a control group consisting of 144 single patients with multiple trauma undergoing standard MSCT according to our trauma room protocol. All MSCT studies were conducted using a 4-detector row scanner. (1) For the study group (Triage MSCT), average time for patient transfer and preparation was 2.9 min (2.5–4.3 min), mean CT examination time was 2.1 min (1.7–2.4 min); image reconstruction took 4.0 min (3.3–4.3 min). Total time in scanner room was 8.9 min (7.7–11.3 min), resulting in a maximal productivity of 6.7 patients per hour. Image transfer to the digital picture archive and communication system archive was completed after an average 9.5 min (8.9–10.8 min). (2) For the control group (single casualty MSCT), the mean time for patient transfer and preparation was 20.4 min (9.0–39.2 min), mean examination time was 6.0 min (3.1–11.3 min). Times for image reconstructions were not recorded in the patient series. Mean total time in scanner room was 25.3 min (11.0–72.4 min), resulting in a patient throughput of 2.4 patients per hour. MSCT has potential to serve as a powerful tool in triage of multiple casualty patients. The introduction of a Triage MSCT scanning protocol resulted in an increase of patient throughput per hour by a factor of almost 3.     

高剂量容积旋转调强放射治疗脊柱转移瘤的疗效分析

目的分析容积旋转调强放射治疗脊柱转移瘤的临床疗效。方法采用容积旋转调强放射治疗20例脊柱转移瘤患者,45~60 Gy/15~20次,3 Gy/次,1次/d;采用数字评分法（NRS）、语言模拟疼痛评分法（VRS）、生活质量骨转移量表（EORTC QLQ-BM22）评估患者放疗前至随访结束各个时间段的疼痛缓解和生活质量改善情况。脊髓神经功能采用Frankel分级评价。主要研究终点为疼痛完全缓解,次要研究终点为患者死亡。结果至随访结束,20例脊柱转移瘤患者无疼痛患者数由放疗前0/20例上升至10/14例,差异有统计学意义（t=20.24,P<0.05）。患者NRS评分显示,放疗1和4周疼痛评分均低于放疗前,由（6.50±0.51）分下降至（4.30±0.47）分和（2.50±0.50）分,差异均有统计学意义（t=15.98、27.57,P<0.05）,止痛能维持至随访结束。疼痛缓解伴强阿片类止痛药使用的下降,放疗后6月内强阿片类止痛药使用人数由16/20例下降至6/18例,差异有统计学意义（t=8.46,P<0.05）。EORTC QLQ-BM22生活质量评分显示放疗后患者在疼痛部位、程度和功能方面均较放疗前明显改善,总分由放疗前（46.50±1.50）分下降至（38.35±0.98）分,差异有统计学意义（t=21.51,P<0.05）,社会心理方面变化不大（P>0.05）。放疗前脊髓神经功能缺陷的患者放疗后6个月脊髓神经功能均得到改善,未出现脊髓神经放射性损伤。所有患者中位生存时间为10个月。结论容积旋转调强放射治疗脊柱转移瘤能够明显减轻患者疼痛、显著改善机体功能,患者生活质量明显提高,无脊髓神经放射性损伤等晚期并发症的发生。     

Rhythmogener Stromtod mit zunächst erhaltener Handlungsfähigkeit

A case of delayed death after a low-voltage accident is presented. At first, an obvious source of electricity was not found. However, electric marks were found on the fingers. The identification of the conductor was performed by analysis of the metallisation of the electric marks. The location of the probable conductors in a boiler under the hand basin and the discovery in a standing position prior to collapse in a bathtub indicates that the capability to act was preserved for a short time period. In such rare cases death seems to be a result of cardiac arrhythmia resulting in ventricular fibrillation.     

Applied physiology of squash

Squash is a moderate- to high-intensity intermittent exercise. Players are active 50 to 70% of the playing time. 80% of the time, the ball is in play 10 seconds or less. The rest intervals fit a normal distribution with an average duration of 8 seconds. Heart rate increases rapidly in the first minutes of play and remains stable at approximately 160 beats/min for the whole match no matter what levels the players are. The energy expenditure for medium-skilled players is approximately 2850 kJ/h and over 3000 kJ/h for A grade players. The thermal and metabolic response to squash is similar to that of moderate intensity running. Hyperglycaemia, elevated free fatty acids and growth hormone levels, and low serum insulin values are the common metabolic changes. Blood lactate levels are understandably low due to the very short work to rest pattern of play. Injuries are not frequent in squash but they can occur. Serious eye injuries have been documented and as a result protective equipment is highly recommended. To reduce the possibility of sudden death on the court or after the game, older players that present some risk factors for cardiovascular disease should be warned against smoking after the game and informed of the serious implications of the development of chest pain, or undue tiredness before, during or after squash.     

Prognostic relevance of FDG PET in patients with neurofibromatosis type-1 and malignant peripheral nerve sheath tumours

Purpose In patients with neurofibromatosis type-1 (NF1) and malignant peripheral nerve sheath tumours (MPNSTs), survival rates are low and time to death is often less than 2 years. However, there are patients with a more favourable prognosis who develop metastases rather late or not at all. Since histopathology and tumour grading are not well correlated with prognosis, we aimed to evaluate the potential of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) for prediction of patient outcome in MPNST. Methods FDG PET was performed in 16 patients with NF1 and MPNSTs. Standardised uptake values (SUVs) were calculated for each tumour and correlated to tumour grade and patient outcome in terms of survival or death. Results Three patients with tumour grade II had an SUV <3. None of these patients developed metastases or died during a follow-up of 41–62 months. Thirteen patients with tumour grades II and III had an SUV >3. Only one of these patients is still alive after 20 months; the remaining 12 died within 4–33 months. SUV predicted long-term survival with an accuracy of 94%, compared with 69% for tumour grade. In Kaplan-Meier survival analysis, patients with an SUV >3 had a significantly shorter mean survival time, 13 months, than patients with an SUV <3, in whom the mean survival time was 52 months. Tumour grading did not reveal differences in survival time (15 vs 12 months). Conclusion Tumour SUV obtained by FDG PET was a significant parameter for prediction of survival in NF1 patients with MPNSTs while histopathological tumour grading did not predict outcome.     

Comparative Study of Ureteral Stents Following Endoureterotomy in the Porcine Model: 3 vs 6 Weeks and 7F vs 14F

The aim of the study was to determine the optimal stent size and stenting duration following retrograde endoureterotomy of experimental ureteral strictures. Twenty healthy Large White female pigs were randomly divided into four groups, depending on stent size (7F vs 14F) and stenting duration (3 weeks vs 6 weeks). Three additional pigs were used as the control group. The internal ureteral diameter was measured 2 cm below the lower pole of the right kidney. Histopathological changes of the urinary tract, ultrasonographic and fluoroscopic studies, urine culture, and serum urea and creatine levels were analyzed during the different phases of the study. The study was divided into three phases. Phase I included premodel documentation of the normal urinary tract and laparoscopic ureteral stricture creation. During the second phase 1 month later, the diagnosis and endourologic treatment of strictures were performed. Phase III began 4 weeks after stent removal; follow-up imaging studies and postmortem evaluation of all animals were performed. Ureteral strictures developed in all animals 4 weeks after model creation. Results from ureteral diameter measurements and pathological studies revealed no statistically significant intergroup differences. However, prevalence of urinary infection proved to be directly related to stent size (14F) and permanence (6 weeks). The chi square results suggest a statistically significant relationship between the urinary tract infection and recurrent strictures (α = 0.046). We recommend the use of 7F stents for a period of 3 weeks or less, as these are more easily positioned and result in the reduction of secondary side effects (lower infection rate, less intramural ureteral lesions). A significant relationship between urinary tract infection and stricture recurrence was found in this experimental study.     

经尿道双极等离子体汽化电切术治疗浅表性膀胱肿瘤的疗效观察

目的观察经尿道双极等离子体膀胱肿瘤汽化电切术治疗浅表性膀胱肿瘤的治疗效果。方法对66例浅表性膀胱肿瘤患者行经尿道双极等离子体汽化电切术治疗,术后常规行膀胱化疗药物灌注。结果 66例膀胱肿瘤患者均1次手术切除。手术时间3~55 min,平均(22±15)min,术中均未输血,有2例在肿瘤切除时发生穿孔。术后留置F22三腔单囊管3~5 d拔管,术后有2例行膀胱点滴冲洗24h,无经尿道电切(TUR)综合征发生,无死亡病例。2例术后并发尿道外口狭窄,经尿道扩张后治愈。随访3~48个月,12例复发(18.18%)。结论经尿道双极等离子体膀胱肿瘤汽化电切术具有操作简单、出血少、恢复快、术后并发症低等优点。     

Influence of high-intensity sustained exercise by the lower limbs on gait properties

An abnormal gait mainly comes from structural changes in the musculoskeletal system and degeneration of the nervous system with age. If a temporary decrease of leg muscle function induced by muscle fatigue produces a similar abnormal gait, useful findings regarding the influence of a decrease in leg muscle function on falling by the elderly during gait may be obtained. This study examined the influence of a temporary decrease in leg muscle function induced by high-intensity sustained exercise on gait properties. Fifteen young male adults performed an eccentric barbell squat exercise for 10 repetitions per 10 sets with 2 min rest per set to produce the decrease in leg muscle function. The barbell load was 80% of the subject’s concentric one-repetition maximum (1RM). The following parameters were measured during walking, before and after exercise: stance time, double support time, single support time, step length, base width, gait and toe angles, gait speed, and cadence. Single support time, step length, base width, gait and toe angles, and gait speed, in addition to leg strength and vertical jump performance significantly changed after exercise. When the leg muscle function decreased, the gait became unstable and slow, and subjects kept their body stable during walking by spreading both feet outward, enlarging the base width, and shortening step length and the duration of supporting the body with one leg. Although gait properties induced by a temporary leg muscle function decrease are similar to those of the elderly, it was judged that the gait change would not increase the risk of falling.     

Determination of endurance capacity and prediction of exercise intensities for training and competition in marathon runners

Male and female marathon runners (n = 34) were studied in incremental and continuous running tests under both laboratory and field conditions. Aerobic capacity was determined based on the relationship between the lactate concentration and running velocity. We also analyzed the acid-base balance after the laboratory test of continuous running for 45 min. The individual running velocities in the incremental field test at given lactate concentrations were correlated with the marathon running velocities. Training workouts for six female runners were analyzed, and running speed during endurance training was compared with the lactate-velocity relationship in an incremental laboratory test. The main findings are summarized below. There is a very close relationship between the velocities determined at 2.5, 3, and 4 mmol/l in the incremental field test and the marathon running velocity (r = 0.88-0.99, P less than 0.001). The highest correlation between test and marathon velocities was found at a lactate concentration of 2.5 and 3.0 mmol/l. In field and laboratory running tests lasting 44 and 45 min at a speed chosen in accordance with the runner's current marathon time, lactate levels reached a steady state at approximately 3 mmol/l. A slight increase in blood lactate levels was compensated via respiratory mechanisms. In the continuous treadmill test (n = 8), we recorded the following changes after the first blood sample collection (i.e., 10 min) and post-exercise: blood lactate concentrations rose from 2.2 +/- 0.93 to 3.5 +/- 1.45 mmol/l; the negative base excess increased from -1.2 +/- 3.2 to -3.4 +/- 1.7 mval/l.(ABSTRACT TRUNCATED AT 250 WORDS)     

Potential Air Contamination During CO2 Angiography Using a Hand-Held Syringe: Theoretical Considerations and Gas Chromatography

Purpose To assess air contamination in the hand-held syringes currently used for CO₂ delivery and to determine whether there is an association between their position and the rate of air contamination. Methods Assessment of air contamination in the syringe (20 ml) included theoretical modeling, mathematical calculation, and gas chromatography (GC). The model was used with Fick’s first law to calculate the diffusion of CO₂ and the amount of air contamination. For GC studies, the syringes were placed in the upright, horizontal, and inverted positions and gas samples were obtained after 5, 10, 20, 30, and 60 min. All trials with each position for each sampling time were performed five times. Results The amounts of air contamination with time calculated mathematically were 5–10% less than those of GC. With the diffusivity of air–CO₂ at 0.1599 cm²/sec (9.594 cm²/min), air contamination was calculated to be 60% at 60 min. With GC air contamination was 13% at 5 min, 31% at 20 min, 43% at 30 min, and 68% at 60 min. There was no difference in air contamination between the different syringe positions. Conclusion Air contamination occurs in hand-held syringes filled with CO₂ when they are open to the ambient air. The amounts of air contamination over time are similar among syringes placed in the upright, horizontal, and inverted positions.     

Determining time of death: temperature-dependent postmortem changes in calcineurin A,MARCKS, CaMKII,and protein phosphatase 2A in mouse

While the determination of postmortem interval (PMI) is a crucial and fundamental step in any death investigation, the development of appropriate biochemical methods for PMI estimation is still in its infancy. This study focused on the temperature-dependent postmortem degradation of calcineurin A (CnA), calmodulin-dependent kinase II (CaMKII), myristoylated alanine-rich C-kinase substrate (MARCKs), and protein phosphatase 2A (PP2A) in mice. The results show that MARCKS, CaMKII, and the use of lung tissue do not appear to warrant further study for the determination of PMI in humans. In skeletal muscle, CnA underwent a rapid temperature-dependent cleavage (60 → 57 kDa) over the first 48 h of postmortem interval. At 21°C, this transformation was completed within 24 h. In contrast, PP2A increased within the first 24 h after which it degraded at 21°C but remained stable for up to 96 h at 5°C and 10°C. The 60 → 57 kDa postmortem conversion of CnA was inhibited by addition of protease inhibitors and MDL-28170 indicating a calpain pathway mediates this breakdown. Proteasome inhibition (MG-132) and calmodulin antagonism (calmidazolium) also inhibited this conversion suggesting that other protein degradation pathways also are in play. In contrast, all of the protease inhibitors and calmidazolium but not ethylene glycol tetraacetic acid led to increased levels of PP2A. The data are discussed in terms of developing a useable field-based biochemical assay for postmortem interval determination in humans and understanding the protein degradation pathways that are initiated upon death.