Detection of ∆<Superscript>9</Superscript>-tetrahydrocannabinol in exhaled breath after cannabis smoking and comparison with oral fluid

Exhaled breath is commonly used in alcohol testing, but has been recently demonstrated by scientists from Sweden, Germany, Belgium, Switzerland, and the United States to contain a large number of both volatile and non-volatile substances that can be measured using dedicated devices. ExaBreath^® is a sampling device that collects the bio-aerosol particles from the donor. Approximately 2 min exhaled breath is enough for the test. The device collects the very small bio-aerosols on a filter, which is consecutively incubated into methanol to release drugs at a laboratory. Four occasional cannabis smokers were recruited for this study. Oral fluid, collected with the Quantisal^® device, and exhaled breath were simultaneously collected up to 6 h after smoking a standard joint of cannabis. ?⁹-Tetrahydrocannabinol (THC) was tested using liquid chromatography–tandem mass spectrometry (MS/MS) or gas chromatography–MS/MS for exhaled breath and oral fluid, respectively. Linearity, precision and limit of quantification (5 pg/filter and 0.5 ng/mL for exhaled breath and oral fluid, respectively) were established. In each analytical batch, low and high controls were included. THC was identified in exhaled breath up to 6 h after smoking from all the four subjects, with concentrations in the range 15–1598 pg/filter. THC breath concentrations significantly decreased with time after smoking in all four participants. All the oral fluid specimens tested positive for THC over the 6 h of the study, with concentrations in the range 1–89 ng/mL. 11-Nor-9-carboxy-Δ⁹-tetrahydrocannabinol, the main metabolite of THC was also analysed, but was undetectable in both exhaled breath and oral fluid. This study gives further support to the possibility of using exhaled breath as a new matrix to document exposure to drugs, particularly for cannabis.     

Occurrence of postmortem production of ethylene glycol and propylene glycol in human specimens

We previously established a sensitive gas chromatography–mass spectrometry method for analysis of ethylene glycol (EG), propylene glycol (PG), and diethylene glycol (DEG), and disclosed the presence of appreciable amounts of EG, PG, and DEG in fresh whole blood and urine specimens obtained from nonoccupational healthy humans. These results led us to analyze EG and PG in specimens taken from three human cadavers. EG and PG concentrations in the postmortem blood and solid tissues were much higher than those found in fresh whole blood; their concentrations in many postmortem specimens were more than tenfold those in fresh whole blood specimens, suggesting the postmortem production of EG and PG. Therefore, we examined the time courses of EG and PG concentrations in blood specimens in the absence and presence of saprogenic blood (10 % volume) and/or glucose (3 mg/ml) in vitro, which were left at room temperature for 7 days. EG concentration in fresh blood without any addition decreased slightly during the 7 days. EG concentration in the blood with addition of glucose, and PG concentrations in the blood with and without addition of glucose did not change appreciably during the 7 days. EG and PG concentrations in the blood after addition of 10 % saprogenic blood increased 3.1-fold and 3.5-fold after 7 days, respectively; those after addition of saprogenic blood plus glucose increased 9.1-fold and 11.9-fold after 7 days, respectively. These results show that microorganisms present in the saprogenic blood caused the postmortem production of EG and PG, and the addition of glucose further enhances the EG and PG concentrations, probably acting as the substrate for glycol production by the microorganisms. To our knowledge, this is the first report to describe postmortem production of EG and PG in human specimens.     

Appearance of gas collections after scuba diving death: a computed tomography study in a porcine model

Introduction

Postmortem computed tomography can easily demonstrate gas collections after diving accidents. Thus, it is often used to support the diagnosis of air embolism secondary to barotrauma. However, many other phenomenons (putrefaction, resuscitation maneuvers, and postmortem tissue offgassing) can also cause postmortem gas effusions and lead to a wrong diagnosis of barotrauma.

Objectives

The aim of this study is to determine topography and time of onset of postmortem gas collections respectively due to putrefaction, resuscitation maneuvers, and tissue offgassing.

Materials and methods

A controlled experimental study was conducted on nine pigs. Three groups of three pigs were studied postmortem by CT from H0 to H24: one control group of nonresuscitated nondivers, one group of divers exposed premortem to an absolute maximal pressure of 5 b for 16 min followed by decompression procedures, and one group of nondivers resuscitated by manual ventilation and thoracic compression for 20 min. The study of intravascular gas was conducted using CT scan and correlated with the results of the autopsy.

Results

The CT scan reveals that, starting 3 h after death, a substantial amount of gas is observed in the venous and arterial systems in the group of divers. Arterial gas appears 24 h after death for the resuscitated group and is absent for the first 24 h for the control group. Concerning the putrefaction gas, this provokes intravenous and portal gas collections starting 6 h after death. Subcutaneous emphysema was observed in two of the three animals from the resuscitated group, corresponding to the thoracic compression areas.

Conclusion

In fatal scuba diving accidents, offgassing appears early (starting from the first hour after death) in the venous system then spreads to the arterial system after about 3 h. The presence of intra-arterial gas is therefore not specific to barotrauma. To affirm a death by barotrauma followed by a gas embolism, a postmortem scanner should be conducted very early. Subcutaneous emphysema should not be mistaken as diagnostic criteria of barotrauma because it can be caused by the resuscitation maneuvers.     

Single-scan rest/stress imaging: validation in a porcine model with <Superscript>18</Superscript>F-Flurpiridaz

Purpose

¹⁸F-labeled myocardial flow agents are becoming available for clinical application but the ～2 hour half-life of ¹⁸F complicates their clinical application for rest-stress measurements. The goal of this work is to evaluate in a pig model a single-scan method which provides quantitative rest-stress blood flow in less than 15 minutes.

Methods

Single-scan rest-stress measurements were made using ¹⁸F-Flurpiridaz. Nine scans were performed in healthy pigs and seven scans were performed in injured pigs. A two-injection, single-scan protocol was used in which an adenosine infusion was started 4 minutes after the first injection of ¹⁸F-Flurpiridaz and followed either 3 or 6 minutes later by a second radiotracer injection. In two pigs, microsphere flow measurements were made at rest and during stress. Dynamic images were reoriented into the short axis view, and regions of interest (ROIs) for the 17 myocardial segments were defined in bull’s eye fashion. PET data were fitted with MGH2, a kinetic model with time varying kinetic parameters, in which blood flow changes abruptly with the introduction of adenosine. Rest and stress myocardial blood flow (MBF) were estimated simultaneously.

Results

The first 12–14 minutes of rest-stress PET data were fitted in detail by the MGH2 model, yielding MBF measurement with a mean precision of 0.035 ml/min/cc. Mean myocardial blood flow across pigs was 0.61?±?0.11 mL/min/cc at rest and 1.06?±?0.19 mL/min/cc at stress in healthy pigs and 0.36?±?0.20 mL/min/cc at rest and 0.62?±?0.24 mL/min/cc at stress in the ischemic area. Good agreement was obtained with microsphere flow measurement (slope?=?1.061?±?0.017, intercept?=?0.051?±?0.017, mean difference 0.096?±?0.18 ml/min/cc).

Conclusion

Accurate rest and stress blood flow estimation can be obtained in less than 15 min of PET acquisition. The method is practical and easy to implement suggesting the possibility of clinical translation.

     

Postmortem imaging of antemortem myocardial ischaemia

Objectives

To determine the minimum survival time for detection of antemortem myocardial ischaemia with postmortem imaging (PMI) techniques.

Methods

Nine pigs underwent ligation of the left anterior descending (LAD) (8) and/or right coronary artery (RCA) branch (4), and were killed 30 min–6 h after ligation. PMI (MRI and CT angiography) was performed 2–55 h after euthanasia. Signal intensity of myocardial segments was measured. The hearts were removed, the coronary arteries injected to mark perfused segments, and sections submitted for histology.

Results

MRI T2-weighted sequences showed the ischaemic area as hyperintense in 4/4 LAD ligations with ≥4 h of ischaemia but in 0/4 with <4 h. Histological evidence of ischaemia was present in 4/4 animals after 4 h. Right ventricular ischaemic myocardium was visible on MRI T2-weighted sequences after 6 h of ischaemia in one animal. CT angiography showed the occluded coronary artery in all cases.

Conclusions

Ischaemic lesions of the left ventricle, but not of the right, at least 4 h old can be detected as hyperintense areas on T2-weighted postmortem MRI. This technique is most sensitive in the first 24 h after death. Other sequences did not enhance detection.

Key Points

? Left ventricular myocardial ischaemia/infarction can be demonstrated by postmortem imaging (PMI). ? Ischaemia/infarction is better detected if survival time is at least 4 h. ? Right ventricular ischaemia/infarction is not reliably detected by PMI. ? Computed tomography angiography can demonstrate arterial occlusion.     

Postmortem distribution and redistribution of synthetic cathinones

Purpose

Synthetic cathinones are powerful psychostimulants that have been associated with fatal intoxications. Because of changes that take place following death, postmortem toxicology results require careful interpretation. The purpose of this study was to evaluate the distribution of synthetic cathinones in postmortem specimens in a series of 50 cathinone-positive fatalities.

Methods

Liquid chromatography–quadrupole time-of-flight-mass spectrometry was used to quantitatively identify cathinones in central blood (n = 51), peripheral blood (n = 31), urine (n = 33), liver (n = 22), vitreous humor (n = 1) and stomach contents (n = 1). The distribution of cathinones and the potential for postmortem redistribution was assessed.

Results

Among the 50 cases investigated, a total of nine synthetic cathinones (α-PVP, ethylone, methylone, butylone, MDPV, methedrone, pentylone, 4-MEC, and MDPBP) were identified in 139 specimens. The number of specimens per case ranged from one to six. In cases that included central blood or liver, together with a peripheral blood source, the central/peripheral (C/P) or liver/peripheral (L/P) ratio was calculated to estimate the potential for postmortem redistribution (n = 21 C/P; n = 11 L/P). Methylone and ethylone appeared to exhibit the greatest potential for postmortem redistribution, producing C/P ratios of 4.0 (1.5–6.1) and 2.9 (0.5–9.2), respectively. In contrast, the C/P ratio for α-PVP was 1.1 (0.5–1.9). Differences in C/P ratios between methylone and α-PVP were statistically significant (α = 0.05).

Conclusions

Although synthetic cathinones may exhibit low to moderate postmortem redistribution, significant variability exists due to site- and time-dependent factors. This, in combination with their overall instability, necessitates careful interpretation of postmortem toxicology results.

     

Pharmacokinetics of heroin and its metabolites in vitreous humor and blood in a living pig model

Vitreous humor (VH) is an alternative matrix for drug analysis in forensic toxicology. However, little is known about the distribution of xenobiotics, such as opioids, into VH in living organisms. The aim of this study was to simultaneously measure heroin and metabolite concentrations in blood and VH after injection of heroin in a living pig model. Six pigs were under non-opioid anesthesia during the surgical operation and experiment. Ocular microdialysis was used to acquire dialysate from VH, and a venous catheter was used for blood sampling. Twenty milligrams of heroin was injected intravenously with subsequent sampling of blood and dialysate for 6 h. The samples were analyzed by ultra-performance liquid chromatography–tandem mass spectrometry. Heroin was not detected in VH; 6-monoacetylmorphine (6-MAM) and morphine were first detected in VH after 60 min. The morphine concentration in VH thereafter increased throughout the experimental period. For 6-MAM, C _max was reached after 230 min in VH. In blood, 6-MAM reached C _max after 0.5 min, with a subsequent biphasic elimination phase. The blood and VH 6-MAM concentrations reached equilibrium after 2 h. In blood, morphine reached C _max after 4.3 min, with a subsequent slower elimination than 6-MAM. The blood and VH morphine concentrations were in equilibrium about 6 h after injection of heroin. In conclusion, both 6-MAM and morphine showed slow transport into VH; detection of 6-MAM in VH did not necessarily reflect a recent intake of heroin. Because postmortem changes are expected to be small in VH, these experimental results could assist the interpretation of heroin deaths.     

On-site oral fluid Δ<Superscript>9</Superscript>-tetrahydrocannabinol (THC) screening after controlled smoked,vaporized, and oral cannabis administration

Increasing driving under the influence of cannabis cases is an important short-term consequence of cannabis legalization. On-site oral fluid (OF) testing devices provide advantages for roadside drug screening, because OF Δ⁹-tetrahydrocannabinol (THC) indicates more recent cannabis intake than urine, and it can be collected non-invasively by law enforcement personnel. THC presence in OF primarily results from oromucosal contamination during cannabis inhalation. To date, on-site OF devices were not investigated following edible cannabis. We evaluated sensitivity, specificity, and efficiency of the Dräger DrugTest^® 5000 [DT5000] and Alere? DDS^®2 [DDS2] at various OF THC confirmatory cutoffs following controlled smoked, vaporized, and edible cannabis in frequent and occasional smokers. Times of last positive (t _last) were evaluated for each device, cutoff, and smoking group. At a 5 µg/L OF THC confirmation cutoff, overall performance criteria exceeded the recommended 80% for both devices. At lower THC confirmation cutoffs (1–2 µg/L), true positive results were maximized but sensitivity was <80%. When confirmation cutoffs were below manufacturers’ screening cutoffs (5 µg/L DT5000, 25 µg/L DDS2), false negative results increased. No differences in t _last were observed for DT5000 between the three administration routes, but later t _last times were observed after smoking compared to vaporization with DDS2. Frequent smokers had significantly later median t _last (5 h) compared to occasional smokers (1.5–3.5 h) for all conditions. There were no true positive results at 44 and 50 h with the DT5000 and DDS2, respectively. OF screening followed by confirmatory OF analysis is an important strategy for investigations of driving under the influence of drugs, with these data improving interpretation of cannabinoid OF results.     

Postmortem imaging exposed: an aid in MR imaging of musculoskeletal structures

Objective

To identify factors that influence the quality of postmortem magnetic resonance (MR) images of musculoskeletal (MSK) structures as described in the literature, and to evaluate the extent to which these MR images are affected.

Materials and methods

Four useful studies were retrieved from a PubMed and EMBASE search, covering the literature up to 1 March 2012. Three additional studies were included after a manual search from reference lists.

Results

Four human studies and three animal studies are considered in this review. Postmortem MRI quality can be affected by storage temperature, repeated freezing and thawing and fixation. Provided there was an adequate, but above-freezing storage temperature, postmortem changes in fresh cadavers did not appear to affect the MR image quality of MSK structures up to 14 days after death. Image contrast, signal intensities, and relaxation times are temperature-dependent, regardless of whether the specimen was fresh or postmortem for up to 7 days. Bad image quality can occur owing to accelerated autolysis. Freezing and thawing did not affect image quality, unless repeated too often, or whenever a heating pad was used to speed up the thawing process. Conventional formalin-based fixation leads to swelling of soft tissue and fluid accumulation in joints, and therefore to deteriorated images, with image quality just sufficient to visualize gross anatomy.

Conclusion

Various factors were identified that affect postmortem MR image quality of MSK structures. Postmortem MR image quality was good, except for images of the fixated specimen. Freezing is the preferred method of conservation for specimens that are to be subjected to postmortem MRI.     

Identification and quantitation of a new cathinone designer drug PV9 in an “aroma liquid” product,antemortem whole blood and urine specimens,and a postmortem whole blood specimen in a fatal poisoning case

A couple bought “aroma liquid” and “bath salt” type drugs at a dubious drug shop. Both of them orally took the liquid type drug; although the male subject showed no symptoms, the female subject suffered shivering, convulsions, and low levels of consciousness. The woman was taken to an emergency hospital to receive intensive medical treatment, but died about 20 h after admission. The aroma liquid solution, and the antemortem blood and urine collected during medical treatment at the hospital were brought to our laboratory by the police for analysis of the causative drug(s). In addition, a sample of postmortem femoral vein blood was collected from the cadaver. After some screening tests, we finally identified PV9 (α-POP) in all specimens by gas chromatography–mass spectrometry and liquid chromatography–tandem mass spectrometry (LC–MS–MS). The concentration of PV9 was 18.3 mg/ml in the aroma liquid solution, 45.7 ng/ml in the antemortem blood, 20.3 ng/ml in the antemortem urine, and 180 ng/ml in the postmortem femoral vein blood. The concentrations in antemortem blood and urine and in postmortem blood were greatly lowered by dilution during the intensive medical treatment, including intravenous drip infusion of a large volume of solution. The probable coexistence of a β-hydroxyl metabolite was also investigated by mass chromatography and analysis of fragment ions of the product ion spectrum obtained by LC–MS–MS. To our knowledge, this is the first reported identification and quantitation of PV9 in human specimens in a fatal PV9 poisoning case.     

The delayed effects of irreversible electroporation ablation on nerves

Objective

To evaluate the delayed effects of irreversible electroporation (IRE) ablation on nerves.

Methods

The study was approved by the institutional animal care and use committee. CT-guided IRE-ablation (electric field per distance, 1,500 V/cm; pulse length, 70 μs; number of pulses, 90) of 6 sciatic nerves was performed in 6 pigs that were euthanized 2 months after ablation. The sciatic nerves were harvested immediately after euthanasia for histopathological evaluation. Sections from selected specimens were stained with haematoxylin and eosin (H&E), Masson’s trichrome (MT) method for collagen, and immunohistochemistry was performed for S100 and neurofilaments (markers for Schwann cells and axons, respectively).

Results

All nerves showed a preserved endoneural architecture and presence of numerous small calibre axons associated with Schwann cell hyperplasia, consistent with axonal regeneration. A fibrous scar was observed in the adjacent muscle tissue, confirming ablation at the site examined.

Conclusion

After IRE-ablation of nerves, the preservation of the architecture of the endoneurium and the proliferation of Schwann cells may enable axonal regeneration as demonstrated after 2 months in this study.

Key Points

? Irreversible electroporation (IRE) offers promise for non-thermal tumour ablation. ? Preservation of endoneural architecture and proliferation of Schwann cells follow IRE-ablation. ? Preservation of architecture and proliferation of Schwann cells may enable axonal regeneration. ? Despite morphological regeneration, nerve function remains variable after 2 months.     

Quantitative determination of valproic acid in postmortem blood samples—evidence of strong matrix dependency and instability

Most of the daily work of forensic toxicologists deals with fatal cases resulting from overdoses of licit and illicit drugs. However, another reason for fatalities in patients suffering from epilepsy can be undetectable or subtherapeutic levels of antiepileptic drugs. Some studies have shown a correlation between “sudden unexpected death in epilepsy” (SUDEP) and the ineffective treatment of epilepsy. Low levels of antiepileptic drugs may be a risk factor for SUDEP. The death of a psychiatric patient also suffering from epilepsy inspired the investigation. Subsequent to the death of the patient, the doctor was accused of providing inadequate therapy for epilepsy. The patient was to be treated with valproic acid. We developed and validated a simple method of determining valproic acid levels by gas chromatography–mass spectrometry for serum, but a transfer of the method from serum to postmortem whole blood failed. The method had to be modified and revalidated for postmortem whole blood specimens. A stability study of valproic acid in postmortem blood was conducted, showing a decline of valproic acid levels by 85 % after storage at room temperature for 28 days. During the storage time, the blood samples showed changes in consistency. Depending on the stage of decomposition, it is necessary to perform a determination by standard addition with an equilibration time of 4 h before extraction to achieve reliable results. For a proper interpretation of quantitative results, it is necessary to keep the postmortem decline of valproic acid concentrations in mind.     

FVIIIra, CD15, and tryptase performance in the diagnosis of skin stab wound vitality in forensic pathology

The timing of skin wounds is one of the most challenging problems in forensic pathology. In the first minutes or hours after infliction, histological examination fails to determine whether a wound was sustained before or after death. The aim of this study was to evaluate the use of three immunohistochemical markers (FVIIIra, CD15, and tryptase) for the interpretation of the timing of cutaneous stab wounds. We evaluated these markers in intravital wounds from autopsy cases (n?=?12) and surgical specimens (n?=?58). As controls, we used normal skin samples from autopsies (n?=?8) and an original ex vivo surgical human model of recent postmortem wounds (n?=?24). We found overexpression of FVIIIra in 100 % of vital wounds, but also in 53 % of the controls. The number of CD15-positive cells was higher in wound margins than in internal controls (p?<?0.0001) and was significantly correlated with the time interval between incision and devascularization (p?=?0.0005; minimal time for positivity, 9 min). Using the anti-tryptase antibody, we found that the mast cell degranulation rate was higher in wound margins (p?<?0.0001) and correlated with the time interval (minimal time, 1 min). The sensitivity and specificity for the diagnosis of vitality were respectively 100 and 47 % for FVIIIra, 47 and 100 % for CD15, and 60 and 100 % for tryptase. The inter-observer agreement coefficients were 0.68 for FVIIIra, 0.90 for CD15, and 0.46 for tryptase. Finally, we demonstrated that these markers were not reliable in putrefied or desiccated specimens. In conclusion, CD15 and tryptase, but not FVIIIra, may be useful markers for differentiating recent antemortem from postmortem injuries.     

Forensic aspects of gene expression signatures for age determination in bruises as evaluated in an experimental porcine model

Determining the age of bruises and the force used to inflict the trauma is of crucial importance in both human and veterinary forensic pathology. In the present study, the expression of more than 50 different genes in subcutaneous fat and muscle tissue from experimental bruises in pigs was investigated. The aim was to evaluate if expression signatures of selected genes were capable of determining bruises according to age and the force of impact. Eighteen experimental pigs were anesthetized, and on each animal four blunt traumas were inflicted on the back with a low, moderate or high force. The pigs were euthanized from 1 to 10 h after infliction of the trauma and subcutaneous fat and muscle tissues were sampled. As control, subcutaneous fat and muscle tissues were sampled from two un-injured pigs. Quantitative real-time polymerase chain reaction was performed to evaluate mRNA expression of genes involved in inflammation, tissue damage and repair. Expression signatures of thirteen selected genes in subcutaneous fat but not in muscle tissue reflected the age of bruises with a precision of approximately ±2 h. Moreover, the gene expression signature in the subcutaneous fat was to some extend able to separate bruises inflicted with different forces. Expression signatures of selected genes in the subcutaneous fat will increase the precision of the age determination of bruises in pigs. Further, due to the similarity of porcine and human skin physiology and immunity, these results might also provide valuable information in human forensic science.     

Practical calculation method to estimate the absolute boron concentration in tissues using <Superscript>18</Superscript>F-FBPA PET

Purpose

The purpose of this study was to establish a practical method to estimate the absolute boron concentrations in the tissues based on the standardized uptake values (SUVs) after administration of 4-borono-phenylalanine (BPA) using 4-borono-2-¹⁸F-fluoro-phenylalanine (¹⁸F-FBPA) PET.

Methods

Rat xenograft models of C6 glioma (n = 7, body weight 241 ± 28.0 g) were used for the study. PET was performed 60 min after intravenous injection of ¹⁸F-FBPA (30.5 ± 0.7 MBq). After the PET scanning, BPA-fructose (167.3 ± 18.65 mg/kg) was administered by slow intravenous injection to the same subjects. The rats were killed 60 min after the BPA injection and tissue samples were collected from the major organs and tumors. The absolute boron concentrations (unit: ppm) in the samples were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The boron concentrations in the tissues/tumors were also estimated from the ¹⁸F-FBPA PET images using the following formula: estimated absolute boron concentration (ppm) = 0.0478 × [BPA dose (mg/kg)] × SUV. The measured absolute boron concentrations (mBC) by ICP-OES and the estimated boron concentrations (eBC) from the PET images were compared.

Results

The percent difference between the mBC and eBC calculated based on the SUV_max was ?5.2 ± 21.1% for the blood, ?9.4 ± 22.3% for the brain, 1.6 ± 21.3% for the liver, ?14.3 ± 16.8% for the spleen, ?9.5 ± 27.5% for the pancreas, and 3.4 ± 43.2% for the tumor. Relatively large underestimation was observed for the lung (?48.4 ± 16.2%), small intestine (?37.8 ± 19.3%) and large intestine (?33.9 ± 11.0%), due to the partial volume effect arising from the air or feces contained in these organs. In contrast, relatively large overestimation was observed for the kidney (34.3 ± 29.3%), due to the influence of the high uptake in urine.

Conclusions

The absolute boron concentrations in tissues/tumors can be estimated from the SUVs on ¹⁸F-FBPA PET using a practical formula. Caution must be exercised in interpreting the estimated boron concentrations in the lung, small intestine and large intestine, to prevent the adverse effects of overexposure, which could occur due to underestimation by partial volume effect using PET.

     

Regional distribution and kinetics of [18F]fluciclovine (anti-[18F]FACBC), a tracer of amino acid transport, in subjects with primary prostate cancer

Purpose

[¹⁸F]Fluciclovine (anti-[¹⁸F]FACBC) is a synthetic amino acid developed for PET assessment of the anabolic component of tumour metabolism in clinical routine. This phase 1 trial evaluated the safety, tracer stability and uptake kinetics of [¹⁸F]fluciclovine in patients.

Methods

Six patients with biopsy-proven prostate cancer were investigated with 3-T MRI and PET/CT. All underwent dynamic [¹⁸F]fluciclovine PET/CT of the pelvic area for up to 120 min after injection of 418?±?10 MBq of tracer with simultaneous blood sampling of radioactivity. The kinetics of uptake in tumours and normal tissues were evaluated using standardized uptake values (SUVs) and compartmental modelling.

Results

Tumour deposits as defined by MRI were clearly visualized by PET. Urine excretion was minimal and normal tissue background was low. Uptake of [¹⁸F]fluciclovine in tumour from the blood was rapid and the tumour-to-normal tissue contrast was highest between 1 and 15 min after injection with a 65 % reduction in mean tumour uptake at 90 min after injection. A one-compartment model fitted the tracer kinetics well. Early SUVs correlated well with both the influx rate constant (K ₁) and the volume of distribution of the tracer (V _T). There were no signs of tracer metabolite formation. The product was well tolerated in all patients without significant adverse events.

Conclusion

[¹⁸F]Fluciclovine shows high uptake in prostate cancer deposits and appears safe for use in humans. The production is robust and the formulation stable in vivo. An early imaging window seems to provide the best visual results. SUV measurements capture most of the kinetic information that can be obtained from more advanced models, potentially simplifying quantification in future studies.     

A Pilot Study of Uterine Artery Embolization with Tris-Acryl Gelatin Microspheres in Guinea Pigs

Objective

This study was designed to establish guinea pigs as an animal model for uterine artery embolization (UAE) with tris-acryl gelatin microspheres (TAGM).

Methods

Twenty-five female adult guinea pigs were randomly divided into two groups, including a uterine artery casting mould group (n = 10) and a UAE group (n = 15). Pelvic angiography and vascular casting mould were performed in the first group. The anatomical characters of the pelvic cavity in guinea pigs were described. In the second group, the technical feasibility of performing UAE with TAGM in guinea pigs was investigated. The histopathological slides of the uterus of guinea pigs after UAE were examined to inspect the outcomes of UAE.

Results

The uterine artery springs from the internal iliac artery, ascends tortuously along the cervix, and gives off vertically 8–10 branches to the cervix uteri and uterine horns. The diameters of the trunk of the uterine artery and its first branch were 0.32 ± 0.027 mm and 0.14 ± 0.01 mm, respectively. For UAE animals, the dosages of 40–120 and 100–300 μm TAGM were 0.033 ± 0.003 ml and 0.015 ± 0.002 ml, respectively. On histopathological slides, embosphere particles were found in the first branches of the uterine artery, the subserous arteries, and the intramural arteries. Inflammatory reactions in the uterus were common in guinea pigs after UAE. Local or dispersed areas of necrosis in uterus also were observed in a few guinea pigs.

Conclusions

Guinea pigs are an appropriate and feasible model for UAE with TAGM.     

Time-dependent RNA synthesis in different skin layers after wounding. Experimental investigations in vital and postmortem biopsies

Summary Incision wounds were made on the outer ear of rats and two biopsies were taken for examination after different survival times. In each case a biopsy was made of vital tissue and a second of postmortem tissue after refrigeration for 24 h. The biopsies were exposed to a solution containing the RNA precursor³H-cytidine for 1 h, washed and fixed in formalin. Sections 5 m thick were then autoradiographically prepared and automatically evaluated using Quantimet 920. The intravital specimens showed a significant increase in³H-cytidine incorporation in the basal cell layer after survival times of 10–24 h. No increase was seen in the stratum corneum, corium or cartilage tissue. The investigated distance from the wound margin did not have any significant bearing on the results. The³H-cytidine incorporation rate in postmortem tissue was practically identical with that of vital tissue, but no increase was observed in the rate of RNA synthesis in the basal cells as a function of the age of the wound. It may therefore be assumed that this method provides no additional information as to the age of wounds in postmortem examination.Dedicated to Professor O. Pribilla on the occasion of his 70th birthday