Comparison of desaturation and resaturation response times between transmission and reflectance pulse oximeters

BACKGROUND

In general, there is a response time between actual arterial hypoxemia and its detection by pulse oximeters. We compared the desaturation and resaturation response times between two types of pulse oximeters, transmission and reflectance pulse oximeters, to find out which oximeter has a more rapid response time.

METHODS

Thirty-three ASA 1 or 2 patients were enrolled in this study. A transmission pulse oximeter was placed on the index finger and a reflectance pulse oximeter was placed on the forehead and monitored simultaneously. After the induction of general anesthesia without pre-oxygenation, we waited until the oxygen saturation value of any of two pulse oximeters declined to 90%, and then mask ventilation was started with 100% oxygen. Oxygen saturation was recorded at an interval of 2 s during this time.

RESULTS

The desaturation response time of SpO(2) to 95% after apnea was 82.0 s (interquartile range: 67.0-98.5 s) vs. 94.0 s (interquartile range: 84.0-106.5 s) (P<0.001) and SpO(2) to 90% was 94.0 s (interquartile range: 75.5-109.5 s) vs. 100.0 s (interquartile range: 84.5-114.5 s) (P<0.001) in the reflectance and transmission oximeters, respectively. The resaturation response time from mask ventilation to 100% SpO(2) was 23.2+/-5.6 vs. 28.9+/-7.6 s (P<0.001) in the reflectance and transmission oximeters, respectively.

CONCLUSION

In clinical situations in which rapid changes in oxygen saturation are expected, we recommend the forehead reflectance pulse oximeter because it responds more quickly in detecting oxygen desaturation and resaturation compared with the transmission pulse oximeter.

Managing invasive species in the presence of endogenous technological change with uncertainty

This research incorporates the development and adoption of an induced technology under uncertainty into a conceptual dynamic model to more broadly examine efficient policies for mitigating invasive species infestations. We find that under optimal policy, marginal costs of adopting conventional control measures are equal to the sum of the marginal benefits from development and adoption of new technology, as well as the use of conventional control measures. This result implies that a resource allocation designed for controlling invasive species is not adequate when an induced technology is not considered. Our results also reveal that the shadow values associated with the probabilities of developing and then adopting an induced technology increase as the shadow values associated with the stock of an invasive species population increase.

Optimization of trichloroethylene degradation using soluble methane monooxygenase of Methylosinus trichosporium OB3b expressed in recombinant bacteria

By complementing cell-free extracts of Pseudomonas putida F1/pSMMO20 with purified soluble methane monooxygenase (sMMO) components of Methylosinus trichosporium OB3b, the low cloned-gene sMMO activity in the recombinant strain was found to be due to incomplete activity of the hydroxylase component. To address this incomplete activity, additional sMMO-expressing strains were formed by transferring mmo-containing pSMMO20 and pSMMO50 into various bacterial species including pseudomonads and alpha-2 subdivision strains such as methanotrophs, methylotrophs, Agrobacterium tumefaciens A114, and Rhizobium meliloti 102F34 (11 new strains screened); sMMO activity was detected in the last two strains. To increase plasmid segregational stability, the hok/sok locus originally from Escherichia coli plasmid R1 was inserted downstream of the mmo locus of pSMMO20 (resulting in pSMMO40) and found to enhance plasmid stability in P. putida F1 and R. meliloti 102F34 (first report of hok/sok in Rhizobium). To further increase sMMO activity, a modified Whittenbury minimal medium was selected from various minimal and complex media based on trichloroethylene (TCE) degradation and growth rates and was improved by removing the sMMO-inhibiting metal ions [Cu(II), Ni(II), and Zn(II)] and chloramphenicol from the medium and by supplementing with an iron source (3.6 microM of ferrous ammonium sulfate). Using chemostat-grown P. putida F1/pSMMO40, it was found that sMMO activity was higher for cells grown at higher dilution rates. These optimization efforts resulted in a twofold increase in the extent of TCE degradation and more consistent sMMO activity.

Practical anatomic landmarks for determining the insertion depth of central venous catheter in paediatric patients

BACKGROUND

Various methods have been recommended to decide a proper insertion depth of central venous catheter (CVC). The carina is recommended as a useful target level for the CVC tip position. We evaluated the sternal head of a right clavicle and the nipples as anatomic landmarks for determining the optimal depth of CVC in paediatric patients.

METHODS

Ninety children, <5 yr, undergoing catheterization through the right internal jugular vein were enrolled. The insertion depth was determined as follows. The insertion point was designated as 'Point I'. The sternal head of the right clavicle was called 'Point A' and the midpoint of the perpendicular line drawn from Point A to the line connecting both nipples was called 'Point B'. The insertion depth of CVC was determined by adding the two distances (from I to A and from A to B) and subtracting 0.5 cm from this. A chest radiography was taken and the distance of the CVC tip from the carina level was measured by the Picture Archiving and Communicating System.

RESULTS

The mean distance of the CVC tip from the carina level was 0.1 (1.0) (P=0.293) cm above the carina (95% CI 0.1 cm below the carina-0.3 cm above the carina). There was no specific relationship between the distance of the CVC tip from the carina level and the patients' age, height, and weight.

CONCLUSIONS

The CVC tip could be placed near the carina by using the external landmarks without any formulae, images, and devices in children in our study.

Detection of small hepatocellular carcinoma: comparison of conventional gadolinium-enhanced MRI with gadolinium-enhanced MRI after the administration of ferucarbotran

We compared the diagnostic efficacy of gadolinium (Gd)-enhanced MRI with that of Gd-enhanced MRI after administration of ferucarbotran for revealing small hypervascular hepatocellular carcinomas (HCCs). 24 patients with 34 HCCs (ranging in size from 0.6-2.0 cm) underwent Gd-enhanced three-dimensional dynamic MRI followed, after an interval of 5-11 days (mean, 7 days), by Gd-enhanced three-dimensional dynamic MRI after administration of ferucarbotran. The two Gd-enhanced arterial-phase MRI scans were compared quantitatively by measuring the tumour-liver contrast-to-noise ratio (CNR) and qualitatively by evaluating the tumour-liver contrast using matched-pairs analysis. The tumour-liver CNR with Gd-enhanced arterial-phase imaging after ferucarbotran (250.3 +/- 103.7) was higher than that with Gd-enhanced arterial-phase imaging (221.1 +/- 96.1) (p < 0.001). Matched-pairs analysis indicated that, for three lesions, the relative tumour-liver contrast was slightly better with Gd-enhanced arterial-phase imaging after ferucarbotran than with conventional Gd-enhanced arterial-phase imaging; however, in the case of the remaining 31 lesions, the two images were equivalent. We concluded that, although Gd-enhanced arterial-phase imaging after ferucarbotran results in better tumour-liver CNR than Gd-enhanced arterial-phase imaging, the ability of the two techniques to reveal small hypervascular HCCs is the same.

GlideScope video laryngoscope: a randomized clinical trial in 203 paediatric patients

BACKGROUND

The GlideScope intubating device has been reported to provide a comparable or superior laryngoscopic view compared with direct laryngoscopy in adults. This study compared the use of the GlideScope with direct laryngoscopy for the laryngoscopic view and intubation time in children.

METHODS

The laryngoscopic view in 203 children was scored using both the Macintosh laryngoscope and the GlideScope using Cormack and Lehane (C&L) grades. After scoring each laryngoscopic view with and without BURP, the patients were randomly allocated to two groups. The trachea was intubated using direct laryngoscopy (Group DL, n=100) or the GlideScope (Group GS, n=103). We compared C&L grades for the two views in the same patient, and also the time to intubate for each group.

RESULTS

The GlideScope improved the view without BURP in the patients with C&L grade 2 (16/26, P<0.01) and with C&L grades 3 and 4 (7/11, P<0.05). The view with BURP was also improved by the GlideScope in C&L grade 2 (4/9, P<0.05) and with C&L grades 3 and 4 (4/5, P=0.059). The mean time for tracheal intubation was 36.0 (17.9) s in the GS group and 23.8 (13.9) s in the DL group (P<0.001).

CONCLUSIONS

In children, the GlideScope provided a laryngoscopic view equal to or better than that of direct laryngoscopy but required a longer time for intubation.

Visceral fat accumulation induced by a high-fat diet causes the atrophy of mesenteric lymph nodes in obese mice

OBJECTIVE

A high intake of fat in the diet plays a crucial role in promoting obesity and obesity-related pathologies, and especially visceral obesity is closely associated with obesity-related complications. Because adipose tissue is anatomically associated with lymph nodes, the secondary lymphoid organ, we hypothesized that fat tissue-derived factors may influence the cellularity of lymphoid tissue embedded in fat.

METHODS AND PROCEDURES

Mesenteric and inguinal lymph nodes were isolated from obese mice fed a high-fat diet and control mice fed a regular diet. T-cell population, activation state, and the extent of apoptosis were determined by flow cytometric analysis or terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) assay.

RESULTS

The weight of mesenteric lymph nodes and the total number of lymphoid cells in the obese mice significantly decreased compared with those in the control mice; however, no change was observed in the weight of inguinal lymph nodes. The numbers of CD4(+) and CD8(+) T cells in the mesenteric lymph nodes of obese mice significantly decreased compared with those of the control. Enhanced T-cell activation and apoptosis were observed in the mesenteric lymph node cells of the obese mice. The treatment of lymph node cells with free fatty acids, oxidative stress, and chylomicrons, which are obesity-related factors, resulted in lymph node T-cell activation and apoptosis.

DISCUSSION

These results suggest that visceral fat accumulation with a high-fat diet can cause the atrophy of mesenteric lymph nodes by enhancing activation-induced lymphoid cell apoptosis. Dietary fat-induced visceral obesity may be crucial for obesity-related immune dysfunction.

Delayed pharmacological pre-conditioning effect of mitochondrial ATP-sensitive potassium channel opener on neurologic injury in a rabbit model of spinal cord ischemia

BACKGROUND

Diazoxide, pharmacological openers of mitochondrial ATP-sensitive potassium channels have been shown to induce early pre-conditioning in the spinal cord. Here, the authors investigated whether diazoxide also induce delayed pre-conditioning and thereby reduce neurologic complications using a rabbit model of spinal cord ischemia.

METHODS

Infrarenal blood flow was interrupted for 20 min in 21 rabbits. Non-treated control animals received no pre-treatment. Diazoxide (5 mg/kg) were given 48 h before 20 min ischemia in the 48-h DZ group, whereas 15-min DZ group received diazoxide (5 mg/kg) 15 min before 20-min ischemia. Neurological functions were evaluated using Johnson scores for 3 days after reperfusion, after which, spinal cords were procured for hematoxylin and eosin staining for cell counting.

RESULTS

Johnson scores revealed a marked improvement in both the diazoxide-treated groups vs. the non-treated control group at 3, 24, 48, and 72 h after reperfusion (P<0.01). The histologic changes were proportional to the Johnson scores, with better preservation of motor neuron numbers in the animals of the 48-h DZ and 15-min DZ group relative to the non-treated controls (81+/-12, 90+/-10, 50+/-23 motor neurons, respectively, P<0.01). No difference was found between the 48-h DZ group and 15-min DZ group with respect to the Johnson scores or neuron numbers.

CONCLUSIONS

The study demonstrates that pre-treatment with diazoxide 48 h before ischemia, induce delayed pharmacological pre-conditioning, thereby significantly improving clinical neurologic scores and histologic findings in this animal model.

Finite width and local field corrections to spin coulomb drag in a quasi-two-dimensional electron gas

We study the spin Coulomb drag in a quasi-two-dimensional electron gas of finite transverse width, including local field corrections beyond the random phase approximation (RPA). We find that the finite transverse width of the electron gas causes a significant reduction of the spin Coulomb drag. This reduction, however, is largely compensated by the enhancement coming from the inclusion of many-body local field effects beyond the RPA, thereby restoring good agreement with the experimental observations by C. P. Weber et al. [Nature (London) 437, 1330 (2005)].

Alternative method for predicting optimal insertion depth of the laryngeal tube in children

BACKGROUND

Little information is available about the accuracy of the teeth mark on the laryngeal tube (LT) as a guide to correct placement in children. The aim of this crossover study was to evaluate three methods for optimal insertion depth of the size (#) 2 tube in children weighing 12-25 kg.

METHOD

In 24 children, the LT #2 was consecutively inserted by three different methods: (A) until the thick teeth mark on the tube was aligned with the upper incisors, (B) until resistance was felt, and (C) by inserting to a depth, previously measured, of the curved distance between the cricoid cartilage and the upper incisor. In each case, the depth of insertion, the degree of effective ventilation, the presence of leakage, and the fibreoptic view were assessed.

RESULTS

Insertion based on the teeth mark led to a shorter insertion depth and a greater incidence of inadequate ventilation compared with the other two methods. There was no difference in the adequacy of ventilation between methods B and C. The vocal cords were more easily identified with methods B (62.5%) and C (75%) than with method A (12.5%).

CONCLUSIONS

Insertion of the LT #2 aligned with the teeth mark can result in a shallow insertion depth and inadequate ventilation. The measured distance from the cricoid cartilage to the upper incisor offers alternative guidance for correct LT insertion.

Comparison of femoral arterial blood pressure with radial arterial blood pressure and noninvasive upper arm blood pressure in the reperfusion period during liver transplantation

PURPOSE

The reperfusion period during liver transplantation is hemodynamically unstable. Accurate blood pressure measurements are the mainstay for the efficient management of abrupt cardiovascular changes. We sought to compare femoral arterial blood pressure (FABP) with radial arterial blood pressure (RABP) and noninvasive upper arm blood pressure (NIBP) in the reperfusion period.

METHODS

Thirty-six adult living donor liver recipients were enrolled in this prospective study. Blood pressures in 3 locations were simultaneously recorded from 1 minute before reperfusion to 15 minutes after reperfusion. We evaluated agreements between FABP and RABP and between FABP and NIBP using intraclass correlation coefficients. Also, we investigated the rates of postreperfusion syndrome (PRS) based on the measurements from 3 locations.

RESULTS

After reperfusion, the mean and diastolic RABP agreed more with the corresponding FABP than NIBP. However, systolic NIBP showed high agreement with FABP from 3 to 10 minutes after reperfusion in contrast with the moderate agreement between systolic RABP with FABP, and systolic values of NIBP than RABP were closer to FABP. The rates of PRS based on FABP, RABP, and NIBP measurements were 50.0% (18/36), 80.6% (29/36), and 50.0% (18/36), respectively.

CONCLUSIONS

We believe that NIBP in addition to RABP may be considered to be a reliable alternative when FABP is not available to evaluate hemodynamic instability in the reperfusion period during liver transplantation.

Plutonium and 137Cs in surface water of the South Pacific Ocean

The present plutonium and 137Cs concentrations in South Pacific Ocean surface waters were determined. The water samples were collected in the South Pacific mid-latitude region (32.5 degrees S) during the BEAGLE expedition conducted in 2003-04 by JAMSTEC. 239,240Pu concentrations in surface seawater of the South Pacific were in the range of 0.5 to 4.1 mBq m(-3), whereas 137Cs concentrations ranged from 0.07 to 1.7 Bq m(-3). The observed 239,240Pu and 137Cs concentrations in the South Pacific were almost of the same level as those in the North Pacific subtropical gyre. The surface 239,240Pu in the South Pacific subtropical gyre showed larger spatial variations than 137Cs, as it may be affected by physical and biogeochemical processes. The 239,240Pu/137Cs activity ratios, which reflect biogeochemical processes in seawater, were generally smaller than that observed in global fallout, except for the most eastern station. The 239,240Pu/137Cs ratios in the South Pacific tend to be higher than that in the North Pacific. The relationships between anthropogenic radionuclides and oceanographic parameters such as salinity and nutrients were examined. The 137Cs concentrations in the western South Pacific (the Tasman Sea) and the eastern South Pacific were negatively correlated with the phosphate concentration, whereas there is no correlation between the 137Cs and nutrients concentrations in the South Pacific subtropical gyre. The mutual relationships between anthropogenic radionuclides and oceanographic parameters are important for better understanding of transport processes of anthropogenic radionuclides and their fate in the South Pacific.

Evaluation of corrected flow time in oesophageal Doppler as a predictor of fluid responsiveness

BACKGROUND

Corrected flow time (FTc) by oesophageal Doppler is considered to be a 'static' preload index. We evaluated the ability of FTc to predict fluid responsiveness and compared this with the abilities of other preload indices, such as pulse pressure variation (PPV), central venous pressure (CVP), and left ventricular end-diastolic area index (LVEDAI).

METHODS

Twenty neurosurgical patients were studied. After induction of anaesthesia, FTc, PPV, LVEDAI, CVP, and stroke volume index (SVI) were measured before and 12 min after fluid loading with 6% hydroxyethyl starch solution (7 ml kg(-1)). Responders and non-responders were defined as those patients with an SVI increase >or= 10% or < 10% after fluid loading, respectively. Pearson's correlation was used to assess correlations between changes in SVI and initial haemodynamic variables. Receiver operating characteristic (ROC) curves were constructed and compared to evaluate the overall performance of preload indices (FTc, PPV, LVEDAI, and CVP) in terms of predicting fluid responsiveness.

RESULTS

FTc and PPV before fluid loading differed between responders (n = 11) and non-responders (n = 9), and correlated with changes in SVI (r = -0.515 and r = 0.696, respectively), which was opposite to that observed for CVP or LVEDAI. Areas under ROC curves for FTc [0.944 (SD 0.058)] and PPV [0.909 (0.069)] were significantly greater than those for CVP [0.540 (0.133), P < 0.001] and LVEDAI [0.495 (0.133), P < 0.001]. The optimal threshold value given by ROC analysis was 357 ms for FTc.

CONCLUSIONS

In this study, FTc predicted fluid responsiveness. However, FTc should be used in conjunction with other clinical information.

Granulocytic sarcoma manifested as a parametrial mass mimicking a haemorrhagic abscess: a case report with CT and MR findings

Granulocytic sarcoma is a neoplasm arising from myeloid precursor cells and frequently accompanies leukaemia and myeloproliferative disorders. Granulocytic sarcoma can arise anywhere, and it frequently involves bones, perineural tissues and lymph nodes. However, granulocytic sarcoma in the female genital organs is uncommon, and it is extremely rare that it presents as an adnexal or parametrial mass. We report here the CT and MR findings in a case of granulocytic sarcoma that manifested as a uterine cervical and parametrial mass mimicking a haemorrhagic abscess in a 50-year-old woman with chronic myelogenous leukaemia.

Effects of sevoflurane on the cAMP-induced short-circuit current in mouse tracheal epithelium and recombinant Cl- (CFTR) and K+ (KCNQ1) channels

BACKGROUND

An optimal level of airway surface liquid is essential for mucociliary clearance in lungs. The cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) and KCNQ1 channels in tracheal epithelium play key roles in luminal and basolateral membranes, respectively. The aim of this study was to examine the effects of sevoflurane on cAMP-induced chloride secretion by the mouse tracheal epithelium and the modulation of recombinant CFTR and KCNQ1 channels.

METHODS

The equivalent short-circuit current (Isc) of the mouse tracheal epithelium was measured using a flow-type Ussing chamber technique. Inhibition of Na+ absorption was achieved through the luminal application of amiloride. cAMP-dependent Cl- secretion was evoked by forskolin and isobutylmethylxanthine (Fsk/IBMX) applied to the basolateral side. The effect of sevoflurane on CFTR and KCNQ1 channels was assessed using a whole-cell patch clamp in human embryonic kidney 293T cells expressing CFTR and KCNQ1 channels.

RESULTS

Fsk/IBMX induced a sustained Isc that was suppressed by the application of sevoflurane [decreased by 49 (4.5)% at 190 microM]. The Fsk/IBMX-induced Isc was also blocked by basolateral application of chromanol 293B, a blocker of the KCNQ1 K+ channel. In KCNQ1-expressing cells, sevoflurane 190 microM reduced the outward currents to 59 (4.9)% at 80 mV. The CFTR current was not affected by sevoflurane (approximately 360 microM).

CONCLUSIONS

These results suggest that the inhibition of KCNQ1 underlies sevoflurane-induced decrease in airway secretion.

The clinical and immunogenetic characteristics of adult-onset type 1 diabetes mellitus in Korea

Although the HLA class II alleles and immunological abnormalities are associated with type 1 diabetes mellitus (T1DM) in all racial groups, there are considerable variations in the genotypes and the prevalence of autoantibodies. In order to investigate the characteristics of the immunogenetic patterns and to use these as an early diagnostic tool and guideline for a therapeutic plan, we examined the clinical characteristics and the patterns of anti-GAD antibody (GADA), IA-2 antibody (IA-2A), HLA-DR and HLA-DQ in Korean adult-onset T1DM patients. Adult-onset patients had higher serum C-peptide levels than child-onset patients. In adult-onset patients, the prevalence of GADA and IA-2A were 59.5% and 15.3% respectively, and increased frequencies of HLADR4 and-DR9 were found. The frequencies of HLADQA1,-DQB1 and-DQ heterodimers were similar to those of the control, but child-onset patients had high frequencies of the HLA-DR3,-DR4,-DR9, DQA1*0301, DQA1*0501 and DQB1*0201 genotypes. In conclusion, Korean adult-onset T1DM patients had a lower prevalence of GADA, which was comparable to that found in Caucasian patients. The detection of GADA might help to predict the insulin dependency of adult-onset diabetes. Difference in the frequencies of diabetes associated with HLA type suggests that there might be a heterogeneity in the pathogenesis of diabetes according to the age of onset.

Paraesthesia during the needle-through-needle and the double segment technique for combined spinal epidural anaesthesia*

Paraesthesia during regional anaesthesia is an unpleasant sensation for patients and, more importantly, in some cases it is related to neurological injury. Relatively few studies have been conducted on the frequency of paraesthesia during combined spinal epidural anaesthesia. We compared two combined spinal epidural anaesthesia techniques: the needle-through-needle technique and the double segment technique in this respect. We randomly allocated 116 parturients undergoing elective Caesarean section to receive anaesthesia using one of these techniques. Both techniques were performed using a 27G pencil point needle, an 18G Tuohy needle, and a 20G multiport epidural catheter from the same manufacturer. The overall frequency of paraesthesia was higher in the needle-through-needle technique group (56.9% vs. 31.6%, p = 0.011). The frequency of paraesthesia at spinal needle insertion was 20.7% in the needle-through-needle technique group and 8.8% in the double segment technique group; whereas the frequency of paraesthesia at epidural catheter insertion was 46.6% in the needle-through-needle technique group and 24.6% in the double segment technique group.

Depth of a central venous catheter tip: length of insertion guideline for pediatric patients

BACKGROUND

In pediatric patients, several studies have been undertaken to establish central venous catheter (CVC) tip optimal depth. Assessments of catheter tip position using chest radiographs may be misleading, whereas transesophageal echocardiography (TEE) has been shown to accurately monitor catheter tip placement at the superior vena cava-right atrial (SVC-RA) junction. The aim of this study was to issue a guideline for ideal catheter insertion depth, from the right internal jugular vein (IJV) using TEE to confirm the position of the catheter tip at the SVC-RA junction.

METHODS

Over a 6-month period, we studied 60 right internal jugular vein catheterizations in infants and children undergoing surgery for congenital heart disease. Positions of CVC tips were confirmed to be at the SVC-RA junction by TEE. Distance from the skin puncture site to the SVC-RA junction, height, weight, and age were recorded.

RESULTS

Distances measured were found to be highly correlated with patient height. The following guideline allows the CVC tip to be positioned above the RA in 97.5% of patients with an accuracy of 95%: optimal depth of insertion (cm) = 1.7 + (0.07 x height) in patients whose height is between 40 and 140 cm.

CONCLUSION

The model proposed for the insertion of the CVC tip in pediatric patients could be used to prevent inadvertent catheter tip placement into the atrium.

In vivo organ mass of Korean adults obtained from whole-body magnetic resonance data

In vivo organ mass of the Korean adult, male and female were presented for the purpose of radiation protection. A total of 121 healthy volunteers (66 males and 55 females), whose body dimensions were close to that of average Korean adults, were recruited for this study. Whole-body magnetic resonance (MR) images were obtained, and contours of 15 organs (brain, eye, gall bladder, heart, kidney, liver, lung, pancreas, stomach, spleen, testes, thymus, thyroid, urinary bladder and uterus) and 9 bones (femur, tibia + fibula, humerus, radius + ulna, pelvis, cervical spine, thoracic and lumber spine, skull and clavicle) were segmented for organ volume rendering by anatomists using commercial software. Organ and bone masses were calculated by multiplying the Asian reference densities of the corresponding organs and bones by the measured volumes. The resulting organ and bone masses were compared with those of the International Commission of Radiological Protection (ICRP) and the Asian reference data. Significantly large standard deviation was shown in the moving organs of the respiratory and circulatory systems and in the alimentary and urogenital organs that are variable in volume in a single person. Gall bladder and pancreas showed unique Korean organ masses compared with those of ICRP and the Asian reference adults. Different from anatomical data based on autopsy, the in vivo volume and mass in this study can more exactly describe the organ volume of a living human subject for radiation protection. A larger sample size would be required for obtaining statistically more reliable results. It is also needed to establish the reference organ mass of younger age groups for which it is difficult to recruit volunteers and to immobilise the subjects for long-time MR scanning. At present, the data from this study will contribute to the establishment of a Korean reference database.

Paired-organ and other selected absorbed fraction for the Korean Reference Adult Male model

The authors have developed a mathematical model for calculating internal radionuclide dosimetry for the Korean Reference Adult Male, and have also derived paired-organ and other selected inter-organ photon-specific absorbed fractions for this model. Each lung, kidney and adrenal gland was set as a separate source region even though each of them shares an identical physiological function with their complementary half. The thyroid gland was also set as a source region. Specific absorbed fractions (SAFs) were then derived by selecting 10 photon energies from 0.02 to 4.0 MeV inclusive. For this purpose the Monte Carlo methodology was used, and the derived SAF was compared with the resulting value of MIRD Pamphlet No. 5 and ORNL TM-8381, both of which were derived on the basis of the ICRP-23 reference man. The comparison showed that MIRD No. 5 and ORNL TM-8381 resulted in a higher absorbed fraction, but the phantom created on the basis of the Korean reference man led to a higher SAF. The weight of the organs of the phantom, and the size and location of the trunk seem to account for the differences. The energy-dependent differences in the SAFs are considered to be related to the distance between the source and target regions, the composition of the intervening tissues, and the photon energies and mean free paths. Also, as a result of deriving SAFs after setting each separate lung, kidney and adrenal gland as a source region, it was found that, although they are of the same physiological function, each individual organ serves as a source region on its own. Differences were noted in SAFs exerted on the source and target organs in accordance with the location of the organs, that is, whether they were located to the left or right of the source organs. The SAF derived in this study can be used for a more accurate internal radionuclide dosimetry for Koreans and other Orientals whose physiology, lifestyle and dietary habits are similar to those of Koreans.

Physical phantom of typical Korean male for radiation protection purpose

Dose distribution within a human body can be measured using physical anthropomorphic phantoms. In an effort to establish reference Korean physical model, the first Korean physical phantom of average Korean adult male was constructed using computed tomography (CT) images of a healthy volunteer. The body dimension of the subject was close to that of average Korean male. The source images were obtained using fusion positron emission tomography machine at Radiation Health Research Institute in Korea, and ported into rapid prototyping process. The physical phantom was composed of three tissue-equivalent materials: epoxy resin, urethane foam and polyurethane representing bone, lungs and soft tissues, respectively. The densities of the tissue-equivalent materials were close to those recommended by the International Commission on Radiation Units and measurements. To facilitate dose mapping, the phantom was sliced into 2 cm sections. Hole grids for thermoluminescence (TL) dosemeter chips were drilled. To verify the appropriateness of the physical phantom, organ doses of selected organs were measured for reference photon beam, and compared with those computed by tomographic model constructed from the same CT images. Absorbed doses converted from TL relative response showed good agreement within 7% with those calculated.

Effects of oral androstenedione on phospholipid fatty acids, ATP, caspase-3, prostaglandin E(2) and C-reactive protein in serum and livers of pregnant and non-pregnant female rats

Androstenedione, a steroidal dietary supplement taken to enhance athletic performance, could affect serum and liver lipid metabolism, induce liver toxicity or alter inflammatory response depending on dose and duration of exposure. Pregnancy could further exaggerate these effects. To examine this, mature female rats were gavaged with 0, 5, 30 or 60 mg/kg/day androstenedione beginning two weeks prior to mating and continuing through gestation day 19. Non-pregnant female rats were gavaged over the same time frame with 0 or 60 mg/kg/day androstenedione. Serum was collected and livers were removed from dams on gestation day 20 and from non-pregnant rats after 5 weeks of treatment. Androstenedione had no effect on serum total cholesterol, triglycerides or HDL-cholesterol, but significantly decreased C-reactive protein in pregnant rats and prostaglandin E(2) in serum of both pregnant and non-pregnant rats. There were treatment related decreases in liver ATP and, to a lesser degree, caspase-3 and no change in alkaline phosphatase of pregnant female rats. Androstenedione decreased docosahexaenoic acid in both serum and liver phospholipids of pregnant female rats. In conclusion, oral androstenedione did not result in overt hepatotoxicity in pregnant female rats, but produced modest changes in lipid metabolism and may impair regeneration of injured hepatic cells or tissue.